Pileus Git - ~andy/linux/blob - fs/btrfs/inode.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18
  19 #include <linux/kernel.h>
  20 #include <linux/bio.h>
  21 #include <linux/buffer_head.h>
  22 #include <linux/file.h>
  23 #include <linux/fs.h>
  24 #include <linux/pagemap.h>
  25 #include <linux/highmem.h>
  26 #include <linux/time.h>
  27 #include <linux/init.h>
  28 #include <linux/string.h>
  29 #include <linux/backing-dev.h>
  30 #include <linux/mpage.h>
  31 #include <linux/swap.h>
  32 #include <linux/writeback.h>
  33 #include <linux/statfs.h>
  34 #include <linux/compat.h>
  35 #include <linux/aio.h>
  36 #include <linux/bit_spinlock.h>
  37 #include <linux/xattr.h>
  38 #include <linux/posix_acl.h>
  39 #include <linux/falloc.h>
  40 #include <linux/slab.h>
  41 #include <linux/ratelimit.h>
  42 #include <linux/mount.h>
  43 #include <linux/btrfs.h>
  44 #include <linux/blkdev.h>
  45 #include <linux/posix_acl_xattr.h>
  46 #include "ctree.h"
  47 #include "disk-io.h"
  48 #include "transaction.h"
  49 #include "btrfs_inode.h"
  50 #include "print-tree.h"
  51 #include "ordered-data.h"
  52 #include "xattr.h"
  53 #include "tree-log.h"
  54 #include "volumes.h"
  55 #include "compression.h"
  56 #include "locking.h"
  57 #include "free-space-cache.h"
  58 #include "inode-map.h"
  59 #include "backref.h"
  60 #include "hash.h"
  61 #include "props.h"
  62
  63 struct btrfs_iget_args {
  64         struct btrfs_key *location;
  65         struct btrfs_root *root;
  66 };
  67
  68 static const struct inode_operations btrfs_dir_inode_operations;
  69 static const struct inode_operations btrfs_symlink_inode_operations;
  70 static const struct inode_operations btrfs_dir_ro_inode_operations;
  71 static const struct inode_operations btrfs_special_inode_operations;
  72 static const struct inode_operations btrfs_file_inode_operations;
  73 static const struct address_space_operations btrfs_aops;
  74 static const struct address_space_operations btrfs_symlink_aops;
  75 static const struct file_operations btrfs_dir_file_operations;
  76 static struct extent_io_ops btrfs_extent_io_ops;
  77
  78 static struct kmem_cache *btrfs_inode_cachep;
  79 static struct kmem_cache *btrfs_delalloc_work_cachep;
  80 struct kmem_cache *btrfs_trans_handle_cachep;
  81 struct kmem_cache *btrfs_transaction_cachep;
  82 struct kmem_cache *btrfs_path_cachep;
  83 struct kmem_cache *btrfs_free_space_cachep;
  84
  85 #define S_SHIFT 12
  86 static unsigned char btrfs_type_by_mode[S_IFMT >> S_SHIFT] = {
  87         [S_IFREG >> S_SHIFT]    = BTRFS_FT_REG_FILE,
  88         [S_IFDIR >> S_SHIFT]    = BTRFS_FT_DIR,
  89         [S_IFCHR >> S_SHIFT]    = BTRFS_FT_CHRDEV,
  90         [S_IFBLK >> S_SHIFT]    = BTRFS_FT_BLKDEV,
  91         [S_IFIFO >> S_SHIFT]    = BTRFS_FT_FIFO,
  92         [S_IFSOCK >> S_SHIFT]   = BTRFS_FT_SOCK,
  93         [S_IFLNK >> S_SHIFT]    = BTRFS_FT_SYMLINK,
  94 };
  95
  96 static int btrfs_setsize(struct inode *inode, struct iattr *attr);
  97 static int btrfs_truncate(struct inode *inode);
  98 static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent);
  99 static noinline int cow_file_range(struct inode *inode,
 100                                    struct page *locked_page,
 101                                    u64 start, u64 end, int *page_started,
 102                                    unsigned long *nr_written, int unlock);
 103 static struct extent_map *create_pinned_em(struct inode *inode, u64 start,
 104                                            u64 len, u64 orig_start,
 105                                            u64 block_start, u64 block_len,
 106                                            u64 orig_block_len, u64 ram_bytes,
 107                                            int type);
 108
 109 static int btrfs_dirty_inode(struct inode *inode);
 110
 111 static int btrfs_init_inode_security(struct btrfs_trans_handle *trans,
 112                                      struct inode *inode,  struct inode *dir,
 113                                      const struct qstr *qstr)
 114 {
 115         int err;
 116
 117         err = btrfs_init_acl(trans, inode, dir);
 118         if (!err)
 119                 err = btrfs_xattr_security_init(trans, inode, dir, qstr);
 120         return err;
 121 }
 122
 123 /*
 124  * this does all the hard work for inserting an inline extent into
 125  * the btree.  The caller should have done a btrfs_drop_extents so that
 126  * no overlapping inline items exist in the btree
 127  */
 128 static noinline int insert_inline_extent(struct btrfs_trans_handle *trans,
 129                                 struct btrfs_path *path, int extent_inserted,
 130                                 struct btrfs_root *root, struct inode *inode,
 131                                 u64 start, size_t size, size_t compressed_size,
 132                                 int compress_type,
 133                                 struct page **compressed_pages)
 134 {
 135         struct extent_buffer *leaf;
 136         struct page *page = NULL;
 137         char *kaddr;
 138         unsigned long ptr;
 139         struct btrfs_file_extent_item *ei;
 140         int err = 0;
 141         int ret;
 142         size_t cur_size = size;
 143         unsigned long offset;
 144
 145         if (compressed_size && compressed_pages)
 146                 cur_size = compressed_size;
 147
 148         inode_add_bytes(inode, size);
 149
 150         if (!extent_inserted) {
 151                 struct btrfs_key key;
 152                 size_t datasize;
 153
 154                 key.objectid = btrfs_ino(inode);
 155                 key.offset = start;
 156                 btrfs_set_key_type(&key, BTRFS_EXTENT_DATA_KEY);
 157
 158                 datasize = btrfs_file_extent_calc_inline_size(cur_size);
 159                 path->leave_spinning = 1;
 160                 ret = btrfs_insert_empty_item(trans, root, path, &key,
 161                                               datasize);
 162                 if (ret) {
 163                         err = ret;
 164                         goto fail;
 165                 }
 166         }
 167         leaf = path->nodes[0];
 168         ei = btrfs_item_ptr(leaf, path->slots[0],
 169                             struct btrfs_file_extent_item);
 170         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
 171         btrfs_set_file_extent_type(leaf, ei, BTRFS_FILE_EXTENT_INLINE);
 172         btrfs_set_file_extent_encryption(leaf, ei, 0);
 173         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
 174         btrfs_set_file_extent_ram_bytes(leaf, ei, size);
 175         ptr = btrfs_file_extent_inline_start(ei);
 176
 177         if (compress_type != BTRFS_COMPRESS_NONE) {
 178                 struct page *cpage;
 179                 int i = 0;
 180                 while (compressed_size > 0) {
 181                         cpage = compressed_pages[i];
 182                         cur_size = min_t(unsigned long, compressed_size,
 183                                        PAGE_CACHE_SIZE);
 184
 185                         kaddr = kmap_atomic(cpage);
 186                         write_extent_buffer(leaf, kaddr, ptr, cur_size);
 187                         kunmap_atomic(kaddr);
 188
 189                         i++;
 190                         ptr += cur_size;
 191                         compressed_size -= cur_size;
 192                 }
 193                 btrfs_set_file_extent_compression(leaf, ei,
 194                                                   compress_type);
 195         } else {
 196                 page = find_get_page(inode->i_mapping,
 197                                      start >> PAGE_CACHE_SHIFT);
 198                 btrfs_set_file_extent_compression(leaf, ei, 0);
 199                 kaddr = kmap_atomic(page);
 200                 offset = start & (PAGE_CACHE_SIZE - 1);
 201                 write_extent_buffer(leaf, kaddr + offset, ptr, size);
 202                 kunmap_atomic(kaddr);
 203                 page_cache_release(page);
 204         }
 205         btrfs_mark_buffer_dirty(leaf);
 206         btrfs_release_path(path);
 207
 208         /*
 209          * we're an inline extent, so nobody can
 210          * extend the file past i_size without locking
 211          * a page we already have locked.
 212          *
 213          * We must do any isize and inode updates
 214          * before we unlock the pages.  Otherwise we
 215          * could end up racing with unlink.
 216          */
 217         BTRFS_I(inode)->disk_i_size = inode->i_size;
 218         ret = btrfs_update_inode(trans, root, inode);
 219
 220         return ret;
 221 fail:
 222         return err;
 223 }
 224
 225
 226 /*
 227  * conditionally insert an inline extent into the file.  This
 228  * does the checks required to make sure the data is small enough
 229  * to fit as an inline extent.
 230  */
 231 static noinline int cow_file_range_inline(struct btrfs_root *root,
 232                                           struct inode *inode, u64 start,
 233                                           u64 end, size_t compressed_size,
 234                                           int compress_type,
 235                                           struct page **compressed_pages)
 236 {
 237         struct btrfs_trans_handle *trans;
 238         u64 isize = i_size_read(inode);
 239         u64 actual_end = min(end + 1, isize);
 240         u64 inline_len = actual_end - start;
 241         u64 aligned_end = ALIGN(end, root->sectorsize);
 242         u64 data_len = inline_len;
 243         int ret;
 244         struct btrfs_path *path;
 245         int extent_inserted = 0;
 246         u32 extent_item_size;
 247
 248         if (compressed_size)
 249                 data_len = compressed_size;
 250
 251         if (start > 0 ||
 252             actual_end >= PAGE_CACHE_SIZE ||
 253             data_len >= BTRFS_MAX_INLINE_DATA_SIZE(root) ||
 254             (!compressed_size &&
 255             (actual_end & (root->sectorsize - 1)) == 0) ||
 256             end + 1 < isize ||
 257             data_len > root->fs_info->max_inline) {
 258                 return 1;
 259         }
 260
 261         path = btrfs_alloc_path();
 262         if (!path)
 263                 return -ENOMEM;
 264
 265         trans = btrfs_join_transaction(root);
 266         if (IS_ERR(trans)) {
 267                 btrfs_free_path(path);
 268                 return PTR_ERR(trans);
 269         }
 270         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
 271
 272         if (compressed_size && compressed_pages)
 273                 extent_item_size = btrfs_file_extent_calc_inline_size(
 274                    compressed_size);
 275         else
 276                 extent_item_size = btrfs_file_extent_calc_inline_size(
 277                     inline_len);
 278
 279         ret = __btrfs_drop_extents(trans, root, inode, path,
 280                                    start, aligned_end, NULL,
 281                                    1, 1, extent_item_size, &extent_inserted);
 282         if (ret) {
 283                 btrfs_abort_transaction(trans, root, ret);
 284                 goto out;
 285         }
 286
 287         if (isize > actual_end)
 288                 inline_len = min_t(u64, isize, actual_end);
 289         ret = insert_inline_extent(trans, path, extent_inserted,
 290                                    root, inode, start,
 291                                    inline_len, compressed_size,
 292                                    compress_type, compressed_pages);
 293         if (ret && ret != -ENOSPC) {
 294                 btrfs_abort_transaction(trans, root, ret);
 295                 goto out;
 296         } else if (ret == -ENOSPC) {
 297                 ret = 1;
 298                 goto out;
 299         }
 300
 301         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
 302         btrfs_delalloc_release_metadata(inode, end + 1 - start);
 303         btrfs_drop_extent_cache(inode, start, aligned_end - 1, 0);
 304 out:
 305         btrfs_free_path(path);
 306         btrfs_end_transaction(trans, root);
 307         return ret;
 308 }
 309
 310 struct async_extent {
 311         u64 start;
 312         u64 ram_size;
 313         u64 compressed_size;
 314         struct page **pages;
 315         unsigned long nr_pages;
 316         int compress_type;
 317         struct list_head list;
 318 };
 319
 320 struct async_cow {
 321         struct inode *inode;
 322         struct btrfs_root *root;
 323         struct page *locked_page;
 324         u64 start;
 325         u64 end;
 326         struct list_head extents;
 327         struct btrfs_work work;
 328 };
 329
 330 static noinline int add_async_extent(struct async_cow *cow,
 331                                      u64 start, u64 ram_size,
 332                                      u64 compressed_size,
 333                                      struct page **pages,
 334                                      unsigned long nr_pages,
 335                                      int compress_type)
 336 {
 337         struct async_extent *async_extent;
 338
 339         async_extent = kmalloc(sizeof(*async_extent), GFP_NOFS);
 340         BUG_ON(!async_extent); /* -ENOMEM */
 341         async_extent->start = start;
 342         async_extent->ram_size = ram_size;
 343         async_extent->compressed_size = compressed_size;
 344         async_extent->pages = pages;
 345         async_extent->nr_pages = nr_pages;
 346         async_extent->compress_type = compress_type;
 347         list_add_tail(&async_extent->list, &cow->extents);
 348         return 0;
 349 }
 350
 351 /*
 352  * we create compressed extents in two phases.  The first
 353  * phase compresses a range of pages that have already been
 354  * locked (both pages and state bits are locked).
 355  *
 356  * This is done inside an ordered work queue, and the compression
 357  * is spread across many cpus.  The actual IO submission is step
 358  * two, and the ordered work queue takes care of making sure that
 359  * happens in the same order things were put onto the queue by
 360  * writepages and friends.
 361  *
 362  * If this code finds it can't get good compression, it puts an
 363  * entry onto the work queue to write the uncompressed bytes.  This
 364  * makes sure that both compressed inodes and uncompressed inodes
 365  * are written in the same order that the flusher thread sent them
 366  * down.
 367  */
 368 static noinline int compress_file_range(struct inode *inode,
 369                                         struct page *locked_page,
 370                                         u64 start, u64 end,
 371                                         struct async_cow *async_cow,
 372                                         int *num_added)
 373 {
 374         struct btrfs_root *root = BTRFS_I(inode)->root;
 375         u64 num_bytes;
 376         u64 blocksize = root->sectorsize;
 377         u64 actual_end;
 378         u64 isize = i_size_read(inode);
 379         int ret = 0;
 380         struct page **pages = NULL;
 381         unsigned long nr_pages;
 382         unsigned long nr_pages_ret = 0;
 383         unsigned long total_compressed = 0;
 384         unsigned long total_in = 0;
 385         unsigned long max_compressed = 128 * 1024;
 386         unsigned long max_uncompressed = 128 * 1024;
 387         int i;
 388         int will_compress;
 389         int compress_type = root->fs_info->compress_type;
 390         int redirty = 0;
 391
 392         /* if this is a small write inside eof, kick off a defrag */
 393         if ((end - start + 1) < 16 * 1024 &&
 394             (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
 395                 btrfs_add_inode_defrag(NULL, inode);
 396
 397         actual_end = min_t(u64, isize, end + 1);
 398 again:
 399         will_compress = 0;
 400         nr_pages = (end >> PAGE_CACHE_SHIFT) - (start >> PAGE_CACHE_SHIFT) + 1;
 401         nr_pages = min(nr_pages, (128 * 1024UL) / PAGE_CACHE_SIZE);
 402
 403         /*
 404          * we don't want to send crud past the end of i_size through
 405          * compression, that's just a waste of CPU time.  So, if the
 406          * end of the file is before the start of our current
 407          * requested range of bytes, we bail out to the uncompressed
 408          * cleanup code that can deal with all of this.
 409          *
 410          * It isn't really the fastest way to fix things, but this is a
 411          * very uncommon corner.
 412          */
 413         if (actual_end <= start)
 414                 goto cleanup_and_bail_uncompressed;
 415
 416         total_compressed = actual_end - start;
 417
 418         /* we want to make sure that amount of ram required to uncompress
 419          * an extent is reasonable, so we limit the total size in ram
 420          * of a compressed extent to 128k.  This is a crucial number
 421          * because it also controls how easily we can spread reads across
 422          * cpus for decompression.
 423          *
 424          * We also want to make sure the amount of IO required to do
 425          * a random read is reasonably small, so we limit the size of
 426          * a compressed extent to 128k.
 427          */
 428         total_compressed = min(total_compressed, max_uncompressed);
 429         num_bytes = ALIGN(end - start + 1, blocksize);
 430         num_bytes = max(blocksize,  num_bytes);
 431         total_in = 0;
 432         ret = 0;
 433
 434         /*
 435          * we do compression for mount -o compress and when the
 436          * inode has not been flagged as nocompress.  This flag can
 437          * change at any time if we discover bad compression ratios.
 438          */
 439         if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS) &&
 440             (btrfs_test_opt(root, COMPRESS) ||
 441              (BTRFS_I(inode)->force_compress) ||
 442              (BTRFS_I(inode)->flags & BTRFS_INODE_COMPRESS))) {
 443                 WARN_ON(pages);
 444                 pages = kzalloc(sizeof(struct page *) * nr_pages, GFP_NOFS);
 445                 if (!pages) {
 446                         /* just bail out to the uncompressed code */
 447                         goto cont;
 448                 }
 449
 450                 if (BTRFS_I(inode)->force_compress)
 451                         compress_type = BTRFS_I(inode)->force_compress;
 452
 453                 /*
 454                  * we need to call clear_page_dirty_for_io on each
 455                  * page in the range.  Otherwise applications with the file
 456                  * mmap'd can wander in and change the page contents while
 457                  * we are compressing them.
 458                  *
 459                  * If the compression fails for any reason, we set the pages
 460                  * dirty again later on.
 461                  */
 462                 extent_range_clear_dirty_for_io(inode, start, end);
 463                 redirty = 1;
 464                 ret = btrfs_compress_pages(compress_type,
 465                                            inode->i_mapping, start,
 466                                            total_compressed, pages,
 467                                            nr_pages, &nr_pages_ret,
 468                                            &total_in,
 469                                            &total_compressed,
 470                                            max_compressed);
 471
 472                 if (!ret) {
 473                         unsigned long offset = total_compressed &
 474                                 (PAGE_CACHE_SIZE - 1);
 475                         struct page *page = pages[nr_pages_ret - 1];
 476                         char *kaddr;
 477
 478                         /* zero the tail end of the last page, we might be
 479                          * sending it down to disk
 480                          */
 481                         if (offset) {
 482                                 kaddr = kmap_atomic(page);
 483                                 memset(kaddr + offset, 0,
 484                                        PAGE_CACHE_SIZE - offset);
 485                                 kunmap_atomic(kaddr);
 486                         }
 487                         will_compress = 1;
 488                 }
 489         }
 490 cont:
 491         if (start == 0) {
 492                 /* lets try to make an inline extent */
 493                 if (ret || total_in < (actual_end - start)) {
 494                         /* we didn't compress the entire range, try
 495                          * to make an uncompressed inline extent.
 496                          */
 497                         ret = cow_file_range_inline(root, inode, start, end,
 498                                                     0, 0, NULL);
 499                 } else {
 500                         /* try making a compressed inline extent */
 501                         ret = cow_file_range_inline(root, inode, start, end,
 502                                                     total_compressed,
 503                                                     compress_type, pages);
 504                 }
 505                 if (ret <= 0) {
 506                         unsigned long clear_flags = EXTENT_DELALLOC |
 507                                 EXTENT_DEFRAG;
 508                         clear_flags |= (ret < 0) ? EXTENT_DO_ACCOUNTING : 0;
 509
 510                         /*
 511                          * inline extent creation worked or returned error,
 512                          * we don't need to create any more async work items.
 513                          * Unlock and free up our temp pages.
 514                          */
 515                         extent_clear_unlock_delalloc(inode, start, end, NULL,
 516                                                      clear_flags, PAGE_UNLOCK |
 517                                                      PAGE_CLEAR_DIRTY |
 518                                                      PAGE_SET_WRITEBACK |
 519                                                      PAGE_END_WRITEBACK);
 520                         goto free_pages_out;
 521                 }
 522         }
 523
 524         if (will_compress) {
 525                 /*
 526                  * we aren't doing an inline extent round the compressed size
 527                  * up to a block size boundary so the allocator does sane
 528                  * things
 529                  */
 530                 total_compressed = ALIGN(total_compressed, blocksize);
 531
 532                 /*
 533                  * one last check to make sure the compression is really a
 534                  * win, compare the page count read with the blocks on disk
 535                  */
 536                 total_in = ALIGN(total_in, PAGE_CACHE_SIZE);
 537                 if (total_compressed >= total_in) {
 538                         will_compress = 0;
 539                 } else {
 540                         num_bytes = total_in;
 541                 }
 542         }
 543         if (!will_compress && pages) {
 544                 /*
 545                  * the compression code ran but failed to make things smaller,
 546                  * free any pages it allocated and our page pointer array
 547                  */
 548                 for (i = 0; i < nr_pages_ret; i++) {
 549                         WARN_ON(pages[i]->mapping);
 550                         page_cache_release(pages[i]);
 551                 }
 552                 kfree(pages);
 553                 pages = NULL;
 554                 total_compressed = 0;
 555                 nr_pages_ret = 0;
 556
 557                 /* flag the file so we don't compress in the future */
 558                 if (!btrfs_test_opt(root, FORCE_COMPRESS) &&
 559                     !(BTRFS_I(inode)->force_compress)) {
 560                         BTRFS_I(inode)->flags |= BTRFS_INODE_NOCOMPRESS;
 561                 }
 562         }
 563         if (will_compress) {
 564                 *num_added += 1;
 565
 566                 /* the async work queues will take care of doing actual
 567                  * allocation on disk for these compressed pages,
 568                  * and will submit them to the elevator.
 569                  */
 570                 add_async_extent(async_cow, start, num_bytes,
 571                                  total_compressed, pages, nr_pages_ret,
 572                                  compress_type);
 573
 574                 if (start + num_bytes < end) {
 575                         start += num_bytes;
 576                         pages = NULL;
 577                         cond_resched();
 578                         goto again;
 579                 }
 580         } else {
 581 cleanup_and_bail_uncompressed:
 582                 /*
 583                  * No compression, but we still need to write the pages in
 584                  * the file we've been given so far.  redirty the locked
 585                  * page if it corresponds to our extent and set things up
 586                  * for the async work queue to run cow_file_range to do
 587                  * the normal delalloc dance
 588                  */
 589                 if (page_offset(locked_page) >= start &&
 590                     page_offset(locked_page) <= end) {
 591                         __set_page_dirty_nobuffers(locked_page);
 592                         /* unlocked later on in the async handlers */
 593                 }
 594                 if (redirty)
 595                         extent_range_redirty_for_io(inode, start, end);
 596                 add_async_extent(async_cow, start, end - start + 1,
 597                                  0, NULL, 0, BTRFS_COMPRESS_NONE);
 598                 *num_added += 1;
 599         }
 600
 601 out:
 602         return ret;
 603
 604 free_pages_out:
 605         for (i = 0; i < nr_pages_ret; i++) {
 606                 WARN_ON(pages[i]->mapping);
 607                 page_cache_release(pages[i]);
 608         }
 609         kfree(pages);
 610
 611         goto out;
 612 }
 613
 614 /*
 615  * phase two of compressed writeback.  This is the ordered portion
 616  * of the code, which only gets called in the order the work was
 617  * queued.  We walk all the async extents created by compress_file_range
 618  * and send them down to the disk.
 619  */
 620 static noinline int submit_compressed_extents(struct inode *inode,
 621                                               struct async_cow *async_cow)
 622 {
 623         struct async_extent *async_extent;
 624         u64 alloc_hint = 0;
 625         struct btrfs_key ins;
 626         struct extent_map *em;
 627         struct btrfs_root *root = BTRFS_I(inode)->root;
 628         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 629         struct extent_io_tree *io_tree;
 630         int ret = 0;
 631
 632         if (list_empty(&async_cow->extents))
 633                 return 0;
 634
 635 again:
 636         while (!list_empty(&async_cow->extents)) {
 637                 async_extent = list_entry(async_cow->extents.next,
 638                                           struct async_extent, list);
 639                 list_del(&async_extent->list);
 640
 641                 io_tree = &BTRFS_I(inode)->io_tree;
 642
 643 retry:
 644                 /* did the compression code fall back to uncompressed IO? */
 645                 if (!async_extent->pages) {
 646                         int page_started = 0;
 647                         unsigned long nr_written = 0;
 648
 649                         lock_extent(io_tree, async_extent->start,
 650                                          async_extent->start +
 651                                          async_extent->ram_size - 1);
 652
 653                         /* allocate blocks */
 654                         ret = cow_file_range(inode, async_cow->locked_page,
 655                                              async_extent->start,
 656                                              async_extent->start +
 657                                              async_extent->ram_size - 1,
 658                                              &page_started, &nr_written, 0);
 659
 660                         /* JDM XXX */
 661
 662                         /*
 663                          * if page_started, cow_file_range inserted an
 664                          * inline extent and took care of all the unlocking
 665                          * and IO for us.  Otherwise, we need to submit
 666                          * all those pages down to the drive.
 667                          */
 668                         if (!page_started && !ret)
 669                                 extent_write_locked_range(io_tree,
 670                                                   inode, async_extent->start,
 671                                                   async_extent->start +
 672                                                   async_extent->ram_size - 1,
 673                                                   btrfs_get_extent,
 674                                                   WB_SYNC_ALL);
 675                         else if (ret)
 676                                 unlock_page(async_cow->locked_page);
 677                         kfree(async_extent);
 678                         cond_resched();
 679                         continue;
 680                 }
 681
 682                 lock_extent(io_tree, async_extent->start,
 683                             async_extent->start + async_extent->ram_size - 1);
 684
 685                 ret = btrfs_reserve_extent(root,
 686                                            async_extent->compressed_size,
 687                                            async_extent->compressed_size,
 688                                            0, alloc_hint, &ins, 1);
 689                 if (ret) {
 690                         int i;
 691
 692                         for (i = 0; i < async_extent->nr_pages; i++) {
 693                                 WARN_ON(async_extent->pages[i]->mapping);
 694                                 page_cache_release(async_extent->pages[i]);
 695                         }
 696                         kfree(async_extent->pages);
 697                         async_extent->nr_pages = 0;
 698                         async_extent->pages = NULL;
 699
 700                         if (ret == -ENOSPC) {
 701                                 unlock_extent(io_tree, async_extent->start,
 702                                               async_extent->start +
 703                                               async_extent->ram_size - 1);
 704                                 goto retry;
 705                         }
 706                         goto out_free;
 707                 }
 708
 709                 /*
 710                  * here we're doing allocation and writeback of the
 711                  * compressed pages
 712                  */
 713                 btrfs_drop_extent_cache(inode, async_extent->start,
 714                                         async_extent->start +
 715                                         async_extent->ram_size - 1, 0);
 716
 717                 em = alloc_extent_map();
 718                 if (!em) {
 719                         ret = -ENOMEM;
 720                         goto out_free_reserve;
 721                 }
 722                 em->start = async_extent->start;
 723                 em->len = async_extent->ram_size;
 724                 em->orig_start = em->start;
 725                 em->mod_start = em->start;
 726                 em->mod_len = em->len;
 727
 728                 em->block_start = ins.objectid;
 729                 em->block_len = ins.offset;
 730                 em->orig_block_len = ins.offset;
 731                 em->ram_bytes = async_extent->ram_size;
 732                 em->bdev = root->fs_info->fs_devices->latest_bdev;
 733                 em->compress_type = async_extent->compress_type;
 734                 set_bit(EXTENT_FLAG_PINNED, &em->flags);
 735                 set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
 736                 em->generation = -1;
 737
 738                 while (1) {
 739                         write_lock(&em_tree->lock);
 740                         ret = add_extent_mapping(em_tree, em, 1);
 741                         write_unlock(&em_tree->lock);
 742                         if (ret != -EEXIST) {
 743                                 free_extent_map(em);
 744                                 break;
 745                         }
 746                         btrfs_drop_extent_cache(inode, async_extent->start,
 747                                                 async_extent->start +
 748                                                 async_extent->ram_size - 1, 0);
 749                 }
 750
 751                 if (ret)
 752                         goto out_free_reserve;
 753
 754                 ret = btrfs_add_ordered_extent_compress(inode,
 755                                                 async_extent->start,
 756                                                 ins.objectid,
 757                                                 async_extent->ram_size,
 758                                                 ins.offset,
 759                                                 BTRFS_ORDERED_COMPRESSED,
 760                                                 async_extent->compress_type);
 761                 if (ret)
 762                         goto out_free_reserve;
 763
 764                 /*
 765                  * clear dirty, set writeback and unlock the pages.
 766                  */
 767                 extent_clear_unlock_delalloc(inode, async_extent->start,
 768                                 async_extent->start +
 769                                 async_extent->ram_size - 1,
 770                                 NULL, EXTENT_LOCKED | EXTENT_DELALLOC,
 771                                 PAGE_UNLOCK | PAGE_CLEAR_DIRTY |
 772                                 PAGE_SET_WRITEBACK);
 773                 ret = btrfs_submit_compressed_write(inode,
 774                                     async_extent->start,
 775                                     async_extent->ram_size,
 776                                     ins.objectid,
 777                                     ins.offset, async_extent->pages,
 778                                     async_extent->nr_pages);
 779                 alloc_hint = ins.objectid + ins.offset;
 780                 kfree(async_extent);
 781                 if (ret)
 782                         goto out;
 783                 cond_resched();
 784         }
 785         ret = 0;
 786 out:
 787         return ret;
 788 out_free_reserve:
 789         btrfs_free_reserved_extent(root, ins.objectid, ins.offset);
 790 out_free:
 791         extent_clear_unlock_delalloc(inode, async_extent->start,
 792                                      async_extent->start +
 793                                      async_extent->ram_size - 1,
 794                                      NULL, EXTENT_LOCKED | EXTENT_DELALLOC |
 795                                      EXTENT_DEFRAG | EXTENT_DO_ACCOUNTING,
 796                                      PAGE_UNLOCK | PAGE_CLEAR_DIRTY |
 797                                      PAGE_SET_WRITEBACK | PAGE_END_WRITEBACK);
 798         kfree(async_extent);
 799         goto again;
 800 }
 801
 802 static u64 get_extent_allocation_hint(struct inode *inode, u64 start,
 803                                       u64 num_bytes)
 804 {
 805         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 806         struct extent_map *em;
 807         u64 alloc_hint = 0;
 808
 809         read_lock(&em_tree->lock);
 810         em = search_extent_mapping(em_tree, start, num_bytes);
 811         if (em) {
 812                 /*
 813                  * if block start isn't an actual block number then find the
 814                  * first block in this inode and use that as a hint.  If that
 815                  * block is also bogus then just don't worry about it.
 816                  */
 817                 if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
 818                         free_extent_map(em);
 819                         em = search_extent_mapping(em_tree, 0, 0);
 820                         if (em && em->block_start < EXTENT_MAP_LAST_BYTE)
 821                                 alloc_hint = em->block_start;
 822                         if (em)
 823                                 free_extent_map(em);
 824                 } else {
 825                         alloc_hint = em->block_start;
 826                         free_extent_map(em);
 827                 }
 828         }
 829         read_unlock(&em_tree->lock);
 830
 831         return alloc_hint;
 832 }
 833
 834 /*
 835  * when extent_io.c finds a delayed allocation range in the file,
 836  * the call backs end up in this code.  The basic idea is to
 837  * allocate extents on disk for the range, and create ordered data structs
 838  * in ram to track those extents.
 839  *
 840  * locked_page is the page that writepage had locked already.  We use
 841  * it to make sure we don't do extra locks or unlocks.
 842  *
 843  * *page_started is set to one if we unlock locked_page and do everything
 844  * required to start IO on it.  It may be clean and already done with
 845  * IO when we return.
 846  */
 847 static noinline int cow_file_range(struct inode *inode,
 848                                    struct page *locked_page,
 849                                    u64 start, u64 end, int *page_started,
 850                                    unsigned long *nr_written,
 851                                    int unlock)
 852 {
 853         struct btrfs_root *root = BTRFS_I(inode)->root;
 854         u64 alloc_hint = 0;
 855         u64 num_bytes;
 856         unsigned long ram_size;
 857         u64 disk_num_bytes;
 858         u64 cur_alloc_size;
 859         u64 blocksize = root->sectorsize;
 860         struct btrfs_key ins;
 861         struct extent_map *em;
 862         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 863         int ret = 0;
 864
 865         if (btrfs_is_free_space_inode(inode)) {
 866                 WARN_ON_ONCE(1);
 867                 return -EINVAL;
 868         }
 869
 870         num_bytes = ALIGN(end - start + 1, blocksize);
 871         num_bytes = max(blocksize,  num_bytes);
 872         disk_num_bytes = num_bytes;
 873
 874         /* if this is a small write inside eof, kick off defrag */
 875         if (num_bytes < 64 * 1024 &&
 876             (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
 877                 btrfs_add_inode_defrag(NULL, inode);
 878
 879         if (start == 0) {
 880                 /* lets try to make an inline extent */
 881                 ret = cow_file_range_inline(root, inode, start, end, 0, 0,
 882                                             NULL);
 883                 if (ret == 0) {
 884                         extent_clear_unlock_delalloc(inode, start, end, NULL,
 885                                      EXTENT_LOCKED | EXTENT_DELALLOC |
 886                                      EXTENT_DEFRAG, PAGE_UNLOCK |
 887                                      PAGE_CLEAR_DIRTY | PAGE_SET_WRITEBACK |
 888                                      PAGE_END_WRITEBACK);
 889
 890                         *nr_written = *nr_written +
 891                              (end - start + PAGE_CACHE_SIZE) / PAGE_CACHE_SIZE;
 892                         *page_started = 1;
 893                         goto out;
 894                 } else if (ret < 0) {
 895                         goto out_unlock;
 896                 }
 897         }
 898
 899         BUG_ON(disk_num_bytes >
 900                btrfs_super_total_bytes(root->fs_info->super_copy));
 901
 902         alloc_hint = get_extent_allocation_hint(inode, start, num_bytes);
 903         btrfs_drop_extent_cache(inode, start, start + num_bytes - 1, 0);
 904
 905         while (disk_num_bytes > 0) {
 906                 unsigned long op;
 907
 908                 cur_alloc_size = disk_num_bytes;
 909                 ret = btrfs_reserve_extent(root, cur_alloc_size,
 910                                            root->sectorsize, 0, alloc_hint,
 911                                            &ins, 1);
 912                 if (ret < 0)
 913                         goto out_unlock;
 914
 915                 em = alloc_extent_map();
 916                 if (!em) {
 917                         ret = -ENOMEM;
 918                         goto out_reserve;
 919                 }
 920                 em->start = start;
 921                 em->orig_start = em->start;
 922                 ram_size = ins.offset;
 923                 em->len = ins.offset;
 924                 em->mod_start = em->start;
 925                 em->mod_len = em->len;
 926
 927                 em->block_start = ins.objectid;
 928                 em->block_len = ins.offset;
 929                 em->orig_block_len = ins.offset;
 930                 em->ram_bytes = ram_size;
 931                 em->bdev = root->fs_info->fs_devices->latest_bdev;
 932                 set_bit(EXTENT_FLAG_PINNED, &em->flags);
 933                 em->generation = -1;
 934
 935                 while (1) {
 936                         write_lock(&em_tree->lock);
 937                         ret = add_extent_mapping(em_tree, em, 1);
 938                         write_unlock(&em_tree->lock);
 939                         if (ret != -EEXIST) {
 940                                 free_extent_map(em);
 941                                 break;
 942                         }
 943                         btrfs_drop_extent_cache(inode, start,
 944                                                 start + ram_size - 1, 0);
 945                 }
 946                 if (ret)
 947                         goto out_reserve;
 948
 949                 cur_alloc_size = ins.offset;
 950                 ret = btrfs_add_ordered_extent(inode, start, ins.objectid,
 951                                                ram_size, cur_alloc_size, 0);
 952                 if (ret)
 953                         goto out_reserve;
 954
 955                 if (root->root_key.objectid ==
 956                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
 957                         ret = btrfs_reloc_clone_csums(inode, start,
 958                                                       cur_alloc_size);
 959                         if (ret)
 960                                 goto out_reserve;
 961                 }
 962
 963                 if (disk_num_bytes < cur_alloc_size)
 964                         break;
 965
 966                 /* we're not doing compressed IO, don't unlock the first
 967                  * page (which the caller expects to stay locked), don't
 968                  * clear any dirty bits and don't set any writeback bits
 969                  *
 970                  * Do set the Private2 bit so we know this page was properly
 971                  * setup for writepage
 972                  */
 973                 op = unlock ? PAGE_UNLOCK : 0;
 974                 op |= PAGE_SET_PRIVATE2;
 975
 976                 extent_clear_unlock_delalloc(inode, start,
 977                                              start + ram_size - 1, locked_page,
 978                                              EXTENT_LOCKED | EXTENT_DELALLOC,
 979                                              op);
 980                 disk_num_bytes -= cur_alloc_size;
 981                 num_bytes -= cur_alloc_size;
 982                 alloc_hint = ins.objectid + ins.offset;
 983                 start += cur_alloc_size;
 984         }
 985 out:
 986         return ret;
 987
 988 out_reserve:
 989         btrfs_free_reserved_extent(root, ins.objectid, ins.offset);
 990 out_unlock:
 991         extent_clear_unlock_delalloc(inode, start, end, locked_page,
 992                                      EXTENT_LOCKED | EXTENT_DO_ACCOUNTING |
 993                                      EXTENT_DELALLOC | EXTENT_DEFRAG,
 994                                      PAGE_UNLOCK | PAGE_CLEAR_DIRTY |
 995                                      PAGE_SET_WRITEBACK | PAGE_END_WRITEBACK);
 996         goto out;
 997 }
 998
 999 /*
1000  * work queue call back to started compression on a file and pages
1001  */
1002 static noinline void async_cow_start(struct btrfs_work *work)
1003 {
1004         struct async_cow *async_cow;
1005         int num_added = 0;
1006         async_cow = container_of(work, struct async_cow, work);
1007
1008         compress_file_range(async_cow->inode, async_cow->locked_page,
1009                             async_cow->start, async_cow->end, async_cow,
1010                             &num_added);
1011         if (num_added == 0) {
1012                 btrfs_add_delayed_iput(async_cow->inode);
1013                 async_cow->inode = NULL;
1014         }
1015 }
1016
1017 /*
1018  * work queue call back to submit previously compressed pages
1019  */
1020 static noinline void async_cow_submit(struct btrfs_work *work)
1021 {
1022         struct async_cow *async_cow;
1023         struct btrfs_root *root;
1024         unsigned long nr_pages;
1025
1026         async_cow = container_of(work, struct async_cow, work);
1027
1028         root = async_cow->root;
1029         nr_pages = (async_cow->end - async_cow->start + PAGE_CACHE_SIZE) >>
1030                 PAGE_CACHE_SHIFT;
1031
1032         if (atomic_sub_return(nr_pages, &root->fs_info->async_delalloc_pages) <
1033             5 * 1024 * 1024 &&
1034             waitqueue_active(&root->fs_info->async_submit_wait))
1035                 wake_up(&root->fs_info->async_submit_wait);
1036
1037         if (async_cow->inode)
1038                 submit_compressed_extents(async_cow->inode, async_cow);
1039 }
1040
1041 static noinline void async_cow_free(struct btrfs_work *work)
1042 {
1043         struct async_cow *async_cow;
1044         async_cow = container_of(work, struct async_cow, work);
1045         if (async_cow->inode)
1046                 btrfs_add_delayed_iput(async_cow->inode);
1047         kfree(async_cow);
1048 }
1049
1050 static int cow_file_range_async(struct inode *inode, struct page *locked_page,
1051                                 u64 start, u64 end, int *page_started,
1052                                 unsigned long *nr_written)
1053 {
1054         struct async_cow *async_cow;
1055         struct btrfs_root *root = BTRFS_I(inode)->root;
1056         unsigned long nr_pages;
1057         u64 cur_end;
1058         int limit = 10 * 1024 * 1024;
1059
1060         clear_extent_bit(&BTRFS_I(inode)->io_tree, start, end, EXTENT_LOCKED,
1061                          1, 0, NULL, GFP_NOFS);
1062         while (start < end) {
1063                 async_cow = kmalloc(sizeof(*async_cow), GFP_NOFS);
1064                 BUG_ON(!async_cow); /* -ENOMEM */
1065                 async_cow->inode = igrab(inode);
1066                 async_cow->root = root;
1067                 async_cow->locked_page = locked_page;
1068                 async_cow->start = start;
1069
1070                 if (BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS)
1071                         cur_end = end;
1072                 else
1073                         cur_end = min(end, start + 512 * 1024 - 1);
1074
1075                 async_cow->end = cur_end;
1076                 INIT_LIST_HEAD(&async_cow->extents);
1077
1078                 async_cow->work.func = async_cow_start;
1079                 async_cow->work.ordered_func = async_cow_submit;
1080                 async_cow->work.ordered_free = async_cow_free;
1081                 async_cow->work.flags = 0;
1082
1083                 nr_pages = (cur_end - start + PAGE_CACHE_SIZE) >>
1084                         PAGE_CACHE_SHIFT;
1085                 atomic_add(nr_pages, &root->fs_info->async_delalloc_pages);
1086
1087                 btrfs_queue_worker(&root->fs_info->delalloc_workers,
1088                                    &async_cow->work);
1089
1090                 if (atomic_read(&root->fs_info->async_delalloc_pages) > limit) {
1091                         wait_event(root->fs_info->async_submit_wait,
1092                            (atomic_read(&root->fs_info->async_delalloc_pages) <
1093                             limit));
1094                 }
1095
1096                 while (atomic_read(&root->fs_info->async_submit_draining) &&
1097                       atomic_read(&root->fs_info->async_delalloc_pages)) {
1098                         wait_event(root->fs_info->async_submit_wait,
1099                           (atomic_read(&root->fs_info->async_delalloc_pages) ==
1100                            0));
1101                 }
1102
1103                 *nr_written += nr_pages;
1104                 start = cur_end + 1;
1105         }
1106         *page_started = 1;
1107         return 0;
1108 }
1109
1110 static noinline int csum_exist_in_range(struct btrfs_root *root,
1111                                         u64 bytenr, u64 num_bytes)
1112 {
1113         int ret;
1114         struct btrfs_ordered_sum *sums;
1115         LIST_HEAD(list);
1116
1117         ret = btrfs_lookup_csums_range(root->fs_info->csum_root, bytenr,
1118                                        bytenr + num_bytes - 1, &list, 0);
1119         if (ret == 0 && list_empty(&list))
1120                 return 0;
1121
1122         while (!list_empty(&list)) {
1123                 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
1124                 list_del(&sums->list);
1125                 kfree(sums);
1126         }
1127         return 1;
1128 }
1129
1130 /*
1131  * when nowcow writeback call back.  This checks for snapshots or COW copies
1132  * of the extents that exist in the file, and COWs the file as required.
1133  *
1134  * If no cow copies or snapshots exist, we write directly to the existing
1135  * blocks on disk
1136  */
1137 static noinline int run_delalloc_nocow(struct inode *inode,
1138                                        struct page *locked_page,
1139                               u64 start, u64 end, int *page_started, int force,
1140                               unsigned long *nr_written)
1141 {
1142         struct btrfs_root *root = BTRFS_I(inode)->root;
1143         struct btrfs_trans_handle *trans;
1144         struct extent_buffer *leaf;
1145         struct btrfs_path *path;
1146         struct btrfs_file_extent_item *fi;
1147         struct btrfs_key found_key;
1148         u64 cow_start;
1149         u64 cur_offset;
1150         u64 extent_end;
1151         u64 extent_offset;
1152         u64 disk_bytenr;
1153         u64 num_bytes;
1154         u64 disk_num_bytes;
1155         u64 ram_bytes;
1156         int extent_type;
1157         int ret, err;
1158         int type;
1159         int nocow;
1160         int check_prev = 1;
1161         bool nolock;
1162         u64 ino = btrfs_ino(inode);
1163
1164         path = btrfs_alloc_path();
1165         if (!path) {
1166                 extent_clear_unlock_delalloc(inode, start, end, locked_page,
1167                                              EXTENT_LOCKED | EXTENT_DELALLOC |
1168                                              EXTENT_DO_ACCOUNTING |
1169                                              EXTENT_DEFRAG, PAGE_UNLOCK |
1170                                              PAGE_CLEAR_DIRTY |
1171                                              PAGE_SET_WRITEBACK |
1172                                              PAGE_END_WRITEBACK);
1173                 return -ENOMEM;
1174         }
1175
1176         nolock = btrfs_is_free_space_inode(inode);
1177
1178         if (nolock)
1179                 trans = btrfs_join_transaction_nolock(root);
1180         else
1181                 trans = btrfs_join_transaction(root);
1182
1183         if (IS_ERR(trans)) {
1184                 extent_clear_unlock_delalloc(inode, start, end, locked_page,
1185                                              EXTENT_LOCKED | EXTENT_DELALLOC |
1186                                              EXTENT_DO_ACCOUNTING |
1187                                              EXTENT_DEFRAG, PAGE_UNLOCK |
1188                                              PAGE_CLEAR_DIRTY |
1189                                              PAGE_SET_WRITEBACK |
1190                                              PAGE_END_WRITEBACK);
1191                 btrfs_free_path(path);
1192                 return PTR_ERR(trans);
1193         }
1194
1195         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
1196
1197         cow_start = (u64)-1;
1198         cur_offset = start;
1199         while (1) {
1200                 ret = btrfs_lookup_file_extent(trans, root, path, ino,
1201                                                cur_offset, 0);
1202                 if (ret < 0)
1203                         goto error;
1204                 if (ret > 0 && path->slots[0] > 0 && check_prev) {
1205                         leaf = path->nodes[0];
1206                         btrfs_item_key_to_cpu(leaf, &found_key,
1207                                               path->slots[0] - 1);
1208                         if (found_key.objectid == ino &&
1209                             found_key.type == BTRFS_EXTENT_DATA_KEY)
1210                                 path->slots[0]--;
1211                 }
1212                 check_prev = 0;
1213 next_slot:
1214                 leaf = path->nodes[0];
1215                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1216                         ret = btrfs_next_leaf(root, path);
1217                         if (ret < 0)
1218                                 goto error;
1219                         if (ret > 0)
1220                                 break;
1221                         leaf = path->nodes[0];
1222                 }
1223
1224                 nocow = 0;
1225                 disk_bytenr = 0;
1226                 num_bytes = 0;
1227                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1228
1229                 if (found_key.objectid > ino ||
1230                     found_key.type > BTRFS_EXTENT_DATA_KEY ||
1231                     found_key.offset > end)
1232                         break;
1233
1234                 if (found_key.offset > cur_offset) {
1235                         extent_end = found_key.offset;
1236                         extent_type = 0;
1237                         goto out_check;
1238                 }
1239
1240                 fi = btrfs_item_ptr(leaf, path->slots[0],
1241                                     struct btrfs_file_extent_item);
1242                 extent_type = btrfs_file_extent_type(leaf, fi);
1243
1244                 ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
1245                 if (extent_type == BTRFS_FILE_EXTENT_REG ||
1246                     extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1247                         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1248                         extent_offset = btrfs_file_extent_offset(leaf, fi);
1249                         extent_end = found_key.offset +
1250                                 btrfs_file_extent_num_bytes(leaf, fi);
1251                         disk_num_bytes =
1252                                 btrfs_file_extent_disk_num_bytes(leaf, fi);
1253                         if (extent_end <= start) {
1254                                 path->slots[0]++;
1255                                 goto next_slot;
1256                         }
1257                         if (disk_bytenr == 0)
1258                                 goto out_check;
1259                         if (btrfs_file_extent_compression(leaf, fi) ||
1260                             btrfs_file_extent_encryption(leaf, fi) ||
1261                             btrfs_file_extent_other_encoding(leaf, fi))
1262                                 goto out_check;
1263                         if (extent_type == BTRFS_FILE_EXTENT_REG && !force)
1264                                 goto out_check;
1265                         if (btrfs_extent_readonly(root, disk_bytenr))
1266                                 goto out_check;
1267                         if (btrfs_cross_ref_exist(trans, root, ino,
1268                                                   found_key.offset -
1269                                                   extent_offset, disk_bytenr))
1270                                 goto out_check;
1271                         disk_bytenr += extent_offset;
1272                         disk_bytenr += cur_offset - found_key.offset;
1273                         num_bytes = min(end + 1, extent_end) - cur_offset;
1274                         /*
1275                          * force cow if csum exists in the range.
1276                          * this ensure that csum for a given extent are
1277                          * either valid or do not exist.
1278                          */
1279                         if (csum_exist_in_range(root, disk_bytenr, num_bytes))
1280                                 goto out_check;
1281                         nocow = 1;
1282                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
1283                         extent_end = found_key.offset +
1284                                 btrfs_file_extent_inline_len(leaf,
1285                                                      path->slots[0], fi);
1286                         extent_end = ALIGN(extent_end, root->sectorsize);
1287                 } else {
1288                         BUG_ON(1);
1289                 }
1290 out_check:
1291                 if (extent_end <= start) {
1292                         path->slots[0]++;
1293                         goto next_slot;
1294                 }
1295                 if (!nocow) {
1296                         if (cow_start == (u64)-1)
1297                                 cow_start = cur_offset;
1298                         cur_offset = extent_end;
1299                         if (cur_offset > end)
1300                                 break;
1301                         path->slots[0]++;
1302                         goto next_slot;
1303                 }
1304
1305                 btrfs_release_path(path);
1306                 if (cow_start != (u64)-1) {
1307                         ret = cow_file_range(inode, locked_page,
1308                                              cow_start, found_key.offset - 1,
1309                                              page_started, nr_written, 1);
1310                         if (ret)
1311                                 goto error;
1312                         cow_start = (u64)-1;
1313                 }
1314
1315                 if (extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1316                         struct extent_map *em;
1317                         struct extent_map_tree *em_tree;
1318                         em_tree = &BTRFS_I(inode)->extent_tree;
1319                         em = alloc_extent_map();
1320                         BUG_ON(!em); /* -ENOMEM */
1321                         em->start = cur_offset;
1322                         em->orig_start = found_key.offset - extent_offset;
1323                         em->len = num_bytes;
1324                         em->block_len = num_bytes;
1325                         em->block_start = disk_bytenr;
1326                         em->orig_block_len = disk_num_bytes;
1327                         em->ram_bytes = ram_bytes;
1328                         em->bdev = root->fs_info->fs_devices->latest_bdev;
1329                         em->mod_start = em->start;
1330                         em->mod_len = em->len;
1331                         set_bit(EXTENT_FLAG_PINNED, &em->flags);
1332                         set_bit(EXTENT_FLAG_FILLING, &em->flags);
1333                         em->generation = -1;
1334                         while (1) {
1335                                 write_lock(&em_tree->lock);
1336                                 ret = add_extent_mapping(em_tree, em, 1);
1337                                 write_unlock(&em_tree->lock);
1338                                 if (ret != -EEXIST) {
1339                                         free_extent_map(em);
1340                                         break;
1341                                 }
1342                                 btrfs_drop_extent_cache(inode, em->start,
1343                                                 em->start + em->len - 1, 0);
1344                         }
1345                         type = BTRFS_ORDERED_PREALLOC;
1346                 } else {
1347                         type = BTRFS_ORDERED_NOCOW;
1348                 }
1349
1350                 ret = btrfs_add_ordered_extent(inode, cur_offset, disk_bytenr,
1351                                                num_bytes, num_bytes, type);
1352                 BUG_ON(ret); /* -ENOMEM */
1353
1354                 if (root->root_key.objectid ==
1355                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
1356                         ret = btrfs_reloc_clone_csums(inode, cur_offset,
1357                                                       num_bytes);
1358                         if (ret)
1359                                 goto error;
1360                 }
1361
1362                 extent_clear_unlock_delalloc(inode, cur_offset,
1363                                              cur_offset + num_bytes - 1,
1364                                              locked_page, EXTENT_LOCKED |
1365                                              EXTENT_DELALLOC, PAGE_UNLOCK |
1366                                              PAGE_SET_PRIVATE2);
1367                 cur_offset = extent_end;
1368                 if (cur_offset > end)
1369                         break;
1370         }
1371         btrfs_release_path(path);
1372
1373         if (cur_offset <= end && cow_start == (u64)-1) {
1374                 cow_start = cur_offset;
1375                 cur_offset = end;
1376         }
1377
1378         if (cow_start != (u64)-1) {
1379                 ret = cow_file_range(inode, locked_page, cow_start, end,
1380                                      page_started, nr_written, 1);
1381                 if (ret)
1382                         goto error;
1383         }
1384
1385 error:
1386         err = btrfs_end_transaction(trans, root);
1387         if (!ret)
1388                 ret = err;
1389
1390         if (ret && cur_offset < end)
1391                 extent_clear_unlock_delalloc(inode, cur_offset, end,
1392                                              locked_page, EXTENT_LOCKED |
1393                                              EXTENT_DELALLOC | EXTENT_DEFRAG |
1394                                              EXTENT_DO_ACCOUNTING, PAGE_UNLOCK |
1395                                              PAGE_CLEAR_DIRTY |
1396                                              PAGE_SET_WRITEBACK |
1397                                              PAGE_END_WRITEBACK);
1398         btrfs_free_path(path);
1399         return ret;
1400 }
1401
1402 /*
1403  * extent_io.c call back to do delayed allocation processing
1404  */
1405 static int run_delalloc_range(struct inode *inode, struct page *locked_page,
1406                               u64 start, u64 end, int *page_started,
1407                               unsigned long *nr_written)
1408 {
1409         int ret;
1410         struct btrfs_root *root = BTRFS_I(inode)->root;
1411
1412         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW) {
1413                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1414                                          page_started, 1, nr_written);
1415         } else if (BTRFS_I(inode)->flags & BTRFS_INODE_PREALLOC) {
1416                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1417                                          page_started, 0, nr_written);
1418         } else if (!btrfs_test_opt(root, COMPRESS) &&
1419                    !(BTRFS_I(inode)->force_compress) &&
1420                    !(BTRFS_I(inode)->flags & BTRFS_INODE_COMPRESS)) {
1421                 ret = cow_file_range(inode, locked_page, start, end,
1422                                       page_started, nr_written, 1);
1423         } else {
1424                 set_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
1425                         &BTRFS_I(inode)->runtime_flags);
1426                 ret = cow_file_range_async(inode, locked_page, start, end,
1427                                            page_started, nr_written);
1428         }
1429         return ret;
1430 }
1431
1432 static void btrfs_split_extent_hook(struct inode *inode,
1433                                     struct extent_state *orig, u64 split)
1434 {
1435         /* not delalloc, ignore it */
1436         if (!(orig->state & EXTENT_DELALLOC))
1437                 return;
1438
1439         spin_lock(&BTRFS_I(inode)->lock);
1440         BTRFS_I(inode)->outstanding_extents++;
1441         spin_unlock(&BTRFS_I(inode)->lock);
1442 }
1443
1444 /*
1445  * extent_io.c merge_extent_hook, used to track merged delayed allocation
1446  * extents so we can keep track of new extents that are just merged onto old
1447  * extents, such as when we are doing sequential writes, so we can properly
1448  * account for the metadata space we'll need.
1449  */
1450 static void btrfs_merge_extent_hook(struct inode *inode,
1451                                     struct extent_state *new,
1452                                     struct extent_state *other)
1453 {
1454         /* not delalloc, ignore it */
1455         if (!(other->state & EXTENT_DELALLOC))
1456                 return;
1457
1458         spin_lock(&BTRFS_I(inode)->lock);
1459         BTRFS_I(inode)->outstanding_extents--;
1460         spin_unlock(&BTRFS_I(inode)->lock);
1461 }
1462
1463 static void btrfs_add_delalloc_inodes(struct btrfs_root *root,
1464                                       struct inode *inode)
1465 {
1466         spin_lock(&root->delalloc_lock);
1467         if (list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1468                 list_add_tail(&BTRFS_I(inode)->delalloc_inodes,
1469                               &root->delalloc_inodes);
1470                 set_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1471                         &BTRFS_I(inode)->runtime_flags);
1472                 root->nr_delalloc_inodes++;
1473                 if (root->nr_delalloc_inodes == 1) {
1474                         spin_lock(&root->fs_info->delalloc_root_lock);
1475                         BUG_ON(!list_empty(&root->delalloc_root));
1476                         list_add_tail(&root->delalloc_root,
1477                                       &root->fs_info->delalloc_roots);
1478                         spin_unlock(&root->fs_info->delalloc_root_lock);
1479                 }
1480         }
1481         spin_unlock(&root->delalloc_lock);
1482 }
1483
1484 static void btrfs_del_delalloc_inode(struct btrfs_root *root,
1485                                      struct inode *inode)
1486 {
1487         spin_lock(&root->delalloc_lock);
1488         if (!list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1489                 list_del_init(&BTRFS_I(inode)->delalloc_inodes);
1490                 clear_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1491                           &BTRFS_I(inode)->runtime_flags);
1492                 root->nr_delalloc_inodes--;
1493                 if (!root->nr_delalloc_inodes) {
1494                         spin_lock(&root->fs_info->delalloc_root_lock);
1495                         BUG_ON(list_empty(&root->delalloc_root));
1496                         list_del_init(&root->delalloc_root);
1497                         spin_unlock(&root->fs_info->delalloc_root_lock);
1498                 }
1499         }
1500         spin_unlock(&root->delalloc_lock);
1501 }
1502
1503 /*
1504  * extent_io.c set_bit_hook, used to track delayed allocation
1505  * bytes in this file, and to maintain the list of inodes that
1506  * have pending delalloc work to be done.
1507  */
1508 static void btrfs_set_bit_hook(struct inode *inode,
1509                                struct extent_state *state, unsigned long *bits)
1510 {
1511
1512         /*
1513          * set_bit and clear bit hooks normally require _irqsave/restore
1514          * but in this case, we are only testing for the DELALLOC
1515          * bit, which is only set or cleared with irqs on
1516          */
1517         if (!(state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1518                 struct btrfs_root *root = BTRFS_I(inode)->root;
1519                 u64 len = state->end + 1 - state->start;
1520                 bool do_list = !btrfs_is_free_space_inode(inode);
1521
1522                 if (*bits & EXTENT_FIRST_DELALLOC) {
1523                         *bits &= ~EXTENT_FIRST_DELALLOC;
1524                 } else {
1525                         spin_lock(&BTRFS_I(inode)->lock);
1526                         BTRFS_I(inode)->outstanding_extents++;
1527                         spin_unlock(&BTRFS_I(inode)->lock);
1528                 }
1529
1530                 __percpu_counter_add(&root->fs_info->delalloc_bytes, len,
1531                                      root->fs_info->delalloc_batch);
1532                 spin_lock(&BTRFS_I(inode)->lock);
1533                 BTRFS_I(inode)->delalloc_bytes += len;
1534                 if (do_list && !test_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1535                                          &BTRFS_I(inode)->runtime_flags))
1536                         btrfs_add_delalloc_inodes(root, inode);
1537                 spin_unlock(&BTRFS_I(inode)->lock);
1538         }
1539 }
1540
1541 /*
1542  * extent_io.c clear_bit_hook, see set_bit_hook for why
1543  */
1544 static void btrfs_clear_bit_hook(struct inode *inode,
1545                                  struct extent_state *state,
1546                                  unsigned long *bits)
1547 {
1548         /*
1549          * set_bit and clear bit hooks normally require _irqsave/restore
1550          * but in this case, we are only testing for the DELALLOC
1551          * bit, which is only set or cleared with irqs on
1552          */
1553         if ((state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1554                 struct btrfs_root *root = BTRFS_I(inode)->root;
1555                 u64 len = state->end + 1 - state->start;
1556                 bool do_list = !btrfs_is_free_space_inode(inode);
1557
1558                 if (*bits & EXTENT_FIRST_DELALLOC) {
1559                         *bits &= ~EXTENT_FIRST_DELALLOC;
1560                 } else if (!(*bits & EXTENT_DO_ACCOUNTING)) {
1561                         spin_lock(&BTRFS_I(inode)->lock);
1562                         BTRFS_I(inode)->outstanding_extents--;
1563                         spin_unlock(&BTRFS_I(inode)->lock);
1564                 }
1565
1566                 /*
1567                  * We don't reserve metadata space for space cache inodes so we
1568                  * don't need to call dellalloc_release_metadata if there is an
1569                  * error.
1570                  */
1571                 if (*bits & EXTENT_DO_ACCOUNTING &&
1572                     root != root->fs_info->tree_root)
1573                         btrfs_delalloc_release_metadata(inode, len);
1574
1575                 if (root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID
1576                     && do_list && !(state->state & EXTENT_NORESERVE))
1577                         btrfs_free_reserved_data_space(inode, len);
1578
1579                 __percpu_counter_add(&root->fs_info->delalloc_bytes, -len,
1580                                      root->fs_info->delalloc_batch);
1581                 spin_lock(&BTRFS_I(inode)->lock);
1582                 BTRFS_I(inode)->delalloc_bytes -= len;
1583                 if (do_list && BTRFS_I(inode)->delalloc_bytes == 0 &&
1584                     test_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1585                              &BTRFS_I(inode)->runtime_flags))
1586                         btrfs_del_delalloc_inode(root, inode);
1587                 spin_unlock(&BTRFS_I(inode)->lock);
1588         }
1589 }
1590
1591 /*
1592  * extent_io.c merge_bio_hook, this must check the chunk tree to make sure
1593  * we don't create bios that span stripes or chunks
1594  */
1595 int btrfs_merge_bio_hook(int rw, struct page *page, unsigned long offset,
1596                          size_t size, struct bio *bio,
1597                          unsigned long bio_flags)
1598 {
1599         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
1600         u64 logical = (u64)bio->bi_iter.bi_sector << 9;
1601         u64 length = 0;
1602         u64 map_length;
1603         int ret;
1604
1605         if (bio_flags & EXTENT_BIO_COMPRESSED)
1606                 return 0;
1607
1608         length = bio->bi_iter.bi_size;
1609         map_length = length;
1610         ret = btrfs_map_block(root->fs_info, rw, logical,
1611                               &map_length, NULL, 0);
1612         /* Will always return 0 with map_multi == NULL */
1613         BUG_ON(ret < 0);
1614         if (map_length < length + size)
1615                 return 1;
1616         return 0;
1617 }
1618
1619 /*
1620  * in order to insert checksums into the metadata in large chunks,
1621  * we wait until bio submission time.   All the pages in the bio are
1622  * checksummed and sums are attached onto the ordered extent record.
1623  *
1624  * At IO completion time the cums attached on the ordered extent record
1625  * are inserted into the btree
1626  */
1627 static int __btrfs_submit_bio_start(struct inode *inode, int rw,
1628                                     struct bio *bio, int mirror_num,
1629                                     unsigned long bio_flags,
1630                                     u64 bio_offset)
1631 {
1632         struct btrfs_root *root = BTRFS_I(inode)->root;
1633         int ret = 0;
1634
1635         ret = btrfs_csum_one_bio(root, inode, bio, 0, 0);
1636         BUG_ON(ret); /* -ENOMEM */
1637         return 0;
1638 }
1639
1640 /*
1641  * in order to insert checksums into the metadata in large chunks,
1642  * we wait until bio submission time.   All the pages in the bio are
1643  * checksummed and sums are attached onto the ordered extent record.
1644  *
1645  * At IO completion time the cums attached on the ordered extent record
1646  * are inserted into the btree
1647  */
1648 static int __btrfs_submit_bio_done(struct inode *inode, int rw, struct bio *bio,
1649                           int mirror_num, unsigned long bio_flags,
1650                           u64 bio_offset)
1651 {
1652         struct btrfs_root *root = BTRFS_I(inode)->root;
1653         int ret;
1654
1655         ret = btrfs_map_bio(root, rw, bio, mirror_num, 1);
1656         if (ret)
1657                 bio_endio(bio, ret);
1658         return ret;
1659 }
1660
1661 /*
1662  * extent_io.c submission hook. This does the right thing for csum calculation
1663  * on write, or reading the csums from the tree before a read
1664  */
1665 static int btrfs_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
1666                           int mirror_num, unsigned long bio_flags,
1667                           u64 bio_offset)
1668 {
1669         struct btrfs_root *root = BTRFS_I(inode)->root;
1670         int ret = 0;
1671         int skip_sum;
1672         int metadata = 0;
1673         int async = !atomic_read(&BTRFS_I(inode)->sync_writers);
1674
1675         skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
1676
1677         if (btrfs_is_free_space_inode(inode))
1678                 metadata = 2;
1679
1680         if (!(rw & REQ_WRITE)) {
1681                 ret = btrfs_bio_wq_end_io(root->fs_info, bio, metadata);
1682                 if (ret)
1683                         goto out;
1684
1685                 if (bio_flags & EXTENT_BIO_COMPRESSED) {
1686                         ret = btrfs_submit_compressed_read(inode, bio,
1687                                                            mirror_num,
1688                                                            bio_flags);
1689                         goto out;
1690                 } else if (!skip_sum) {
1691                         ret = btrfs_lookup_bio_sums(root, inode, bio, NULL);
1692                         if (ret)
1693                                 goto out;
1694                 }
1695                 goto mapit;
1696         } else if (async && !skip_sum) {
1697                 /* csum items have already been cloned */
1698                 if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
1699                         goto mapit;
1700                 /* we're doing a write, do the async checksumming */
1701                 ret = btrfs_wq_submit_bio(BTRFS_I(inode)->root->fs_info,
1702                                    inode, rw, bio, mirror_num,
1703                                    bio_flags, bio_offset,
1704                                    __btrfs_submit_bio_start,
1705                                    __btrfs_submit_bio_done);
1706                 goto out;
1707         } else if (!skip_sum) {
1708                 ret = btrfs_csum_one_bio(root, inode, bio, 0, 0);
1709                 if (ret)
1710                         goto out;
1711         }
1712
1713 mapit:
1714         ret = btrfs_map_bio(root, rw, bio, mirror_num, 0);
1715
1716 out:
1717         if (ret < 0)
1718                 bio_endio(bio, ret);
1719         return ret;
1720 }
1721
1722 /*
1723  * given a list of ordered sums record them in the inode.  This happens
1724  * at IO completion time based on sums calculated at bio submission time.
1725  */
1726 static noinline int add_pending_csums(struct btrfs_trans_handle *trans,
1727                              struct inode *inode, u64 file_offset,
1728                              struct list_head *list)
1729 {
1730         struct btrfs_ordered_sum *sum;
1731
1732         list_for_each_entry(sum, list, list) {
1733                 trans->adding_csums = 1;
1734                 btrfs_csum_file_blocks(trans,
1735                        BTRFS_I(inode)->root->fs_info->csum_root, sum);
1736                 trans->adding_csums = 0;
1737         }
1738         return 0;
1739 }
1740
1741 int btrfs_set_extent_delalloc(struct inode *inode, u64 start, u64 end,
1742                               struct extent_state **cached_state)
1743 {
1744         WARN_ON((end & (PAGE_CACHE_SIZE - 1)) == 0);
1745         return set_extent_delalloc(&BTRFS_I(inode)->io_tree, start, end,
1746                                    cached_state, GFP_NOFS);
1747 }
1748
1749 /* see btrfs_writepage_start_hook for details on why this is required */
1750 struct btrfs_writepage_fixup {
1751         struct page *page;
1752         struct btrfs_work work;
1753 };
1754
1755 static void btrfs_writepage_fixup_worker(struct btrfs_work *work)
1756 {
1757         struct btrfs_writepage_fixup *fixup;
1758         struct btrfs_ordered_extent *ordered;
1759         struct extent_state *cached_state = NULL;
1760         struct page *page;
1761         struct inode *inode;
1762         u64 page_start;
1763         u64 page_end;
1764         int ret;
1765
1766         fixup = container_of(work, struct btrfs_writepage_fixup, work);
1767         page = fixup->page;
1768 again:
1769         lock_page(page);
1770         if (!page->mapping || !PageDirty(page) || !PageChecked(page)) {
1771                 ClearPageChecked(page);
1772                 goto out_page;
1773         }
1774
1775         inode = page->mapping->host;
1776         page_start = page_offset(page);
1777         page_end = page_offset(page) + PAGE_CACHE_SIZE - 1;
1778
1779         lock_extent_bits(&BTRFS_I(inode)->io_tree, page_start, page_end, 0,
1780                          &cached_state);
1781
1782         /* already ordered? We're done */
1783         if (PagePrivate2(page))
1784                 goto out;
1785
1786         ordered = btrfs_lookup_ordered_extent(inode, page_start);
1787         if (ordered) {
1788                 unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start,
1789                                      page_end, &cached_state, GFP_NOFS);
1790                 unlock_page(page);
1791                 btrfs_start_ordered_extent(inode, ordered, 1);
1792                 btrfs_put_ordered_extent(ordered);
1793                 goto again;
1794         }
1795
1796         ret = btrfs_delalloc_reserve_space(inode, PAGE_CACHE_SIZE);
1797         if (ret) {
1798                 mapping_set_error(page->mapping, ret);
1799                 end_extent_writepage(page, ret, page_start, page_end);
1800                 ClearPageChecked(page);
1801                 goto out;
1802          }
1803
1804         btrfs_set_extent_delalloc(inode, page_start, page_end, &cached_state);
1805         ClearPageChecked(page);
1806         set_page_dirty(page);
1807 out:
1808         unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start, page_end,
1809                              &cached_state, GFP_NOFS);
1810 out_page:
1811         unlock_page(page);
1812         page_cache_release(page);
1813         kfree(fixup);
1814 }
1815
1816 /*
1817  * There are a few paths in the higher layers of the kernel that directly
1818  * set the page dirty bit without asking the filesystem if it is a
1819  * good idea.  This causes problems because we want to make sure COW
1820  * properly happens and the data=ordered rules are followed.
1821  *
1822  * In our case any range that doesn't have the ORDERED bit set
1823  * hasn't been properly setup for IO.  We kick off an async process
1824  * to fix it up.  The async helper will wait for ordered extents, set
1825  * the delalloc bit and make it safe to write the page.
1826  */
1827 static int btrfs_writepage_start_hook(struct page *page, u64 start, u64 end)
1828 {
1829         struct inode *inode = page->mapping->host;
1830         struct btrfs_writepage_fixup *fixup;
1831         struct btrfs_root *root = BTRFS_I(inode)->root;
1832
1833         /* this page is properly in the ordered list */
1834         if (TestClearPagePrivate2(page))
1835                 return 0;
1836
1837         if (PageChecked(page))
1838                 return -EAGAIN;
1839
1840         fixup = kzalloc(sizeof(*fixup), GFP_NOFS);
1841         if (!fixup)
1842                 return -EAGAIN;
1843
1844         SetPageChecked(page);
1845         page_cache_get(page);
1846         fixup->work.func = btrfs_writepage_fixup_worker;
1847         fixup->page = page;
1848         btrfs_queue_worker(&root->fs_info->fixup_workers, &fixup->work);
1849         return -EBUSY;
1850 }
1851
1852 static int insert_reserved_file_extent(struct btrfs_trans_handle *trans,
1853                                        struct inode *inode, u64 file_pos,
1854                                        u64 disk_bytenr, u64 disk_num_bytes,
1855                                        u64 num_bytes, u64 ram_bytes,
1856                                        u8 compression, u8 encryption,
1857                                        u16 other_encoding, int extent_type)
1858 {
1859         struct btrfs_root *root = BTRFS_I(inode)->root;
1860         struct btrfs_file_extent_item *fi;
1861         struct btrfs_path *path;
1862         struct extent_buffer *leaf;
1863         struct btrfs_key ins;
1864         int extent_inserted = 0;
1865         int ret;
1866
1867         path = btrfs_alloc_path();
1868         if (!path)
1869                 return -ENOMEM;
1870
1871         /*
1872          * we may be replacing one extent in the tree with another.
1873          * The new extent is pinned in the extent map, and we don't want
1874          * to drop it from the cache until it is completely in the btree.
1875          *
1876          * So, tell btrfs_drop_extents to leave this extent in the cache.
1877          * the caller is expected to unpin it and allow it to be merged
1878          * with the others.
1879          */
1880         ret = __btrfs_drop_extents(trans, root, inode, path, file_pos,
1881                                    file_pos + num_bytes, NULL, 0,
1882                                    1, sizeof(*fi), &extent_inserted);
1883         if (ret)
1884                 goto out;
1885
1886         if (!extent_inserted) {
1887                 ins.objectid = btrfs_ino(inode);
1888                 ins.offset = file_pos;
1889                 ins.type = BTRFS_EXTENT_DATA_KEY;
1890
1891                 path->leave_spinning = 1;
1892                 ret = btrfs_insert_empty_item(trans, root, path, &ins,
1893                                               sizeof(*fi));
1894                 if (ret)
1895                         goto out;
1896         }
1897         leaf = path->nodes[0];
1898         fi = btrfs_item_ptr(leaf, path->slots[0],
1899                             struct btrfs_file_extent_item);
1900         btrfs_set_file_extent_generation(leaf, fi, trans->transid);
1901         btrfs_set_file_extent_type(leaf, fi, extent_type);
1902         btrfs_set_file_extent_disk_bytenr(leaf, fi, disk_bytenr);
1903         btrfs_set_file_extent_disk_num_bytes(leaf, fi, disk_num_bytes);
1904         btrfs_set_file_extent_offset(leaf, fi, 0);
1905         btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
1906         btrfs_set_file_extent_ram_bytes(leaf, fi, ram_bytes);
1907         btrfs_set_file_extent_compression(leaf, fi, compression);
1908         btrfs_set_file_extent_encryption(leaf, fi, encryption);
1909         btrfs_set_file_extent_other_encoding(leaf, fi, other_encoding);
1910
1911         btrfs_mark_buffer_dirty(leaf);
1912         btrfs_release_path(path);
1913
1914         inode_add_bytes(inode, num_bytes);
1915
1916         ins.objectid = disk_bytenr;
1917         ins.offset = disk_num_bytes;
1918         ins.type = BTRFS_EXTENT_ITEM_KEY;
1919         ret = btrfs_alloc_reserved_file_extent(trans, root,
1920                                         root->root_key.objectid,
1921                                         btrfs_ino(inode), file_pos, &ins);
1922 out:
1923         btrfs_free_path(path);
1924
1925         return ret;
1926 }
1927
1928 /* snapshot-aware defrag */
1929 struct sa_defrag_extent_backref {
1930         struct rb_node node;
1931         struct old_sa_defrag_extent *old;
1932         u64 root_id;
1933         u64 inum;
1934         u64 file_pos;
1935         u64 extent_offset;
1936         u64 num_bytes;
1937         u64 generation;
1938 };
1939
1940 struct old_sa_defrag_extent {
1941         struct list_head list;
1942         struct new_sa_defrag_extent *new;
1943
1944         u64 extent_offset;
1945         u64 bytenr;
1946         u64 offset;
1947         u64 len;
1948         int count;
1949 };
1950
1951 struct new_sa_defrag_extent {
1952         struct rb_root root;
1953         struct list_head head;
1954         struct btrfs_path *path;
1955         struct inode *inode;
1956         u64 file_pos;
1957         u64 len;
1958         u64 bytenr;
1959         u64 disk_len;
1960         u8 compress_type;
1961 };
1962
1963 static int backref_comp(struct sa_defrag_extent_backref *b1,
1964                         struct sa_defrag_extent_backref *b2)
1965 {
1966         if (b1->root_id < b2->root_id)
1967                 return -1;
1968         else if (b1->root_id > b2->root_id)
1969                 return 1;
1970
1971         if (b1->inum < b2->inum)
1972                 return -1;
1973         else if (b1->inum > b2->inum)
1974                 return 1;
1975
1976         if (b1->file_pos < b2->file_pos)
1977                 return -1;
1978         else if (b1->file_pos > b2->file_pos)
1979                 return 1;
1980
1981         /*
1982          * [------------------------------] ===> (a range of space)
1983          *     |<--->|   |<---->| =============> (fs/file tree A)
1984          * |<---------------------------->| ===> (fs/file tree B)
1985          *
1986          * A range of space can refer to two file extents in one tree while
1987          * refer to only one file extent in another tree.
1988          *
1989          * So we may process a disk offset more than one time(two extents in A)
1990          * and locate at the same extent(one extent in B), then insert two same
1991          * backrefs(both refer to the extent in B).
1992          */
1993         return 0;
1994 }
1995
1996 static void backref_insert(struct rb_root *root,
1997                            struct sa_defrag_extent_backref *backref)
1998 {
1999         struct rb_node **p = &root->rb_node;
2000         struct rb_node *parent = NULL;
2001         struct sa_defrag_extent_backref *entry;
2002         int ret;
2003
2004         while (*p) {
2005                 parent = *p;
2006                 entry = rb_entry(parent, struct sa_defrag_extent_backref, node);
2007
2008                 ret = backref_comp(backref, entry);
2009                 if (ret < 0)
2010                         p = &(*p)->rb_left;
2011                 else
2012                         p = &(*p)->rb_right;
2013         }
2014
2015         rb_link_node(&backref->node, parent, p);
2016         rb_insert_color(&backref->node, root);
2017 }
2018
2019 /*
2020  * Note the backref might has changed, and in this case we just return 0.
2021  */
2022 static noinline int record_one_backref(u64 inum, u64 offset, u64 root_id,
2023                                        void *ctx)
2024 {
2025         struct btrfs_file_extent_item *extent;
2026         struct btrfs_fs_info *fs_info;
2027         struct old_sa_defrag_extent *old = ctx;
2028         struct new_sa_defrag_extent *new = old->new;
2029         struct btrfs_path *path = new->path;
2030         struct btrfs_key key;
2031         struct btrfs_root *root;
2032         struct sa_defrag_extent_backref *backref;
2033         struct extent_buffer *leaf;
2034         struct inode *inode = new->inode;
2035         int slot;
2036         int ret;
2037         u64 extent_offset;
2038         u64 num_bytes;
2039
2040         if (BTRFS_I(inode)->root->root_key.objectid == root_id &&
2041             inum == btrfs_ino(inode))
2042                 return 0;
2043
2044         key.objectid = root_id;
2045         key.type = BTRFS_ROOT_ITEM_KEY;
2046         key.offset = (u64)-1;
2047
2048         fs_info = BTRFS_I(inode)->root->fs_info;
2049         root = btrfs_read_fs_root_no_name(fs_info, &key);
2050         if (IS_ERR(root)) {
2051                 if (PTR_ERR(root) == -ENOENT)
2052                         return 0;
2053                 WARN_ON(1);
2054                 pr_debug("inum=%llu, offset=%llu, root_id=%llu\n",
2055                          inum, offset, root_id);
2056                 return PTR_ERR(root);
2057         }
2058
2059         key.objectid = inum;
2060         key.type = BTRFS_EXTENT_DATA_KEY;
2061         if (offset > (u64)-1 << 32)
2062                 key.offset = 0;
2063         else
2064                 key.offset = offset;
2065
2066         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2067         if (WARN_ON(ret < 0))
2068                 return ret;
2069         ret = 0;
2070
2071         while (1) {
2072                 cond_resched();
2073
2074                 leaf = path->nodes[0];
2075                 slot = path->slots[0];
2076
2077                 if (slot >= btrfs_header_nritems(leaf)) {
2078                         ret = btrfs_next_leaf(root, path);
2079                         if (ret < 0) {
2080                                 goto out;
2081                         } else if (ret > 0) {
2082                                 ret = 0;
2083                                 goto out;
2084                         }
2085                         continue;
2086                 }
2087
2088                 path->slots[0]++;
2089
2090                 btrfs_item_key_to_cpu(leaf, &key, slot);
2091
2092                 if (key.objectid > inum)
2093                         goto out;
2094
2095                 if (key.objectid < inum || key.type != BTRFS_EXTENT_DATA_KEY)
2096                         continue;
2097
2098                 extent = btrfs_item_ptr(leaf, slot,
2099                                         struct btrfs_file_extent_item);
2100
2101                 if (btrfs_file_extent_disk_bytenr(leaf, extent) != old->bytenr)
2102                         continue;
2103
2104                 /*
2105                  * 'offset' refers to the exact key.offset,
2106                  * NOT the 'offset' field in btrfs_extent_data_ref, ie.
2107                  * (key.offset - extent_offset).
2108                  */
2109                 if (key.offset != offset)
2110                         continue;
2111
2112                 extent_offset = btrfs_file_extent_offset(leaf, extent);
2113                 num_bytes = btrfs_file_extent_num_bytes(leaf, extent);
2114
2115                 if (extent_offset >= old->extent_offset + old->offset +
2116                     old->len || extent_offset + num_bytes <=
2117                     old->extent_offset + old->offset)
2118                         continue;
2119                 break;
2120         }
2121
2122         backref = kmalloc(sizeof(*backref), GFP_NOFS);
2123         if (!backref) {
2124                 ret = -ENOENT;
2125                 goto out;
2126         }
2127
2128         backref->root_id = root_id;
2129         backref->inum = inum;
2130         backref->file_pos = offset;
2131         backref->num_bytes = num_bytes;
2132         backref->extent_offset = extent_offset;
2133         backref->generation = btrfs_file_extent_generation(leaf, extent);
2134         backref->old = old;
2135         backref_insert(&new->root, backref);
2136         old->count++;
2137 out:
2138         btrfs_release_path(path);
2139         WARN_ON(ret);
2140         return ret;
2141 }
2142
2143 static noinline bool record_extent_backrefs(struct btrfs_path *path,
2144                                    struct new_sa_defrag_extent *new)
2145 {
2146         struct btrfs_fs_info *fs_info = BTRFS_I(new->inode)->root->fs_info;
2147         struct old_sa_defrag_extent *old, *tmp;
2148         int ret;
2149
2150         new->path = path;
2151
2152         list_for_each_entry_safe(old, tmp, &new->head, list) {
2153                 ret = iterate_inodes_from_logical(old->bytenr +
2154                                                   old->extent_offset, fs_info,
2155                                                   path, record_one_backref,
2156                                                   old);
2157                 if (ret < 0 && ret != -ENOENT)
2158                         return false;
2159
2160                 /* no backref to be processed for this extent */
2161                 if (!old->count) {
2162                         list_del(&old->list);
2163                         kfree(old);
2164                 }
2165         }
2166
2167         if (list_empty(&new->head))
2168                 return false;
2169
2170         return true;
2171 }
2172
2173 static int relink_is_mergable(struct extent_buffer *leaf,
2174                               struct btrfs_file_extent_item *fi,
2175                               struct new_sa_defrag_extent *new)
2176 {
2177         if (btrfs_file_extent_disk_bytenr(leaf, fi) != new->bytenr)
2178                 return 0;
2179
2180         if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG)
2181                 return 0;
2182
2183         if (btrfs_file_extent_compression(leaf, fi) != new->compress_type)
2184                 return 0;
2185
2186         if (btrfs_file_extent_encryption(leaf, fi) ||
2187             btrfs_file_extent_other_encoding(leaf, fi))
2188                 return 0;
2189
2190         return 1;
2191 }
2192
2193 /*
2194  * Note the backref might has changed, and in this case we just return 0.
2195  */
2196 static noinline int relink_extent_backref(struct btrfs_path *path,
2197                                  struct sa_defrag_extent_backref *prev,
2198                                  struct sa_defrag_extent_backref *backref)
2199 {
2200         struct btrfs_file_extent_item *extent;
2201         struct btrfs_file_extent_item *item;
2202         struct btrfs_ordered_extent *ordered;
2203         struct btrfs_trans_handle *trans;
2204         struct btrfs_fs_info *fs_info;
2205         struct btrfs_root *root;
2206         struct btrfs_key key;
2207         struct extent_buffer *leaf;
2208         struct old_sa_defrag_extent *old = backref->old;
2209         struct new_sa_defrag_extent *new = old->new;
2210         struct inode *src_inode = new->inode;
2211         struct inode *inode;
2212         struct extent_state *cached = NULL;
2213         int ret = 0;
2214         u64 start;
2215         u64 len;
2216         u64 lock_start;
2217         u64 lock_end;
2218         bool merge = false;
2219         int index;
2220
2221         if (prev && prev->root_id == backref->root_id &&
2222             prev->inum == backref->inum &&
2223             prev->file_pos + prev->num_bytes == backref->file_pos)
2224                 merge = true;
2225
2226         /* step 1: get root */
2227         key.objectid = backref->root_id;
2228         key.type = BTRFS_ROOT_ITEM_KEY;
2229         key.offset = (u64)-1;
2230
2231         fs_info = BTRFS_I(src_inode)->root->fs_info;
2232         index = srcu_read_lock(&fs_info->subvol_srcu);
2233
2234         root = btrfs_read_fs_root_no_name(fs_info, &key);
2235         if (IS_ERR(root)) {
2236                 srcu_read_unlock(&fs_info->subvol_srcu, index);
2237                 if (PTR_ERR(root) == -ENOENT)
2238                         return 0;
2239                 return PTR_ERR(root);
2240         }
2241
2242         /* step 2: get inode */
2243         key.objectid = backref->inum;
2244         key.type = BTRFS_INODE_ITEM_KEY;
2245         key.offset = 0;
2246
2247         inode = btrfs_iget(fs_info->sb, &key, root, NULL);
2248         if (IS_ERR(inode)) {
2249                 srcu_read_unlock(&fs_info->subvol_srcu, index);
2250                 return 0;
2251         }
2252
2253         srcu_read_unlock(&fs_info->subvol_srcu, index);
2254
2255         /* step 3: relink backref */
2256         lock_start = backref->file_pos;
2257         lock_end = backref->file_pos + backref->num_bytes - 1;
2258         lock_extent_bits(&BTRFS_I(inode)->io_tree, lock_start, lock_end,
2259                          0, &cached);
2260
2261         ordered = btrfs_lookup_first_ordered_extent(inode, lock_end);
2262         if (ordered) {
2263                 btrfs_put_ordered_extent(ordered);
2264                 goto out_unlock;
2265         }
2266
2267         trans = btrfs_join_transaction(root);
2268         if (IS_ERR(trans)) {
2269                 ret = PTR_ERR(trans);
2270                 goto out_unlock;
2271         }
2272
2273         key.objectid = backref->inum;
2274         key.type = BTRFS_EXTENT_DATA_KEY;
2275         key.offset = backref->file_pos;
2276
2277         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2278         if (ret < 0) {
2279                 goto out_free_path;
2280         } else if (ret > 0) {
2281                 ret = 0;
2282                 goto out_free_path;
2283         }
2284
2285         extent = btrfs_item_ptr(path->nodes[0], path->slots[0],
2286                                 struct btrfs_file_extent_item);
2287
2288         if (btrfs_file_extent_generation(path->nodes[0], extent) !=
2289             backref->generation)
2290                 goto out_free_path;
2291
2292         btrfs_release_path(path);
2293
2294         start = backref->file_pos;
2295         if (backref->extent_offset < old->extent_offset + old->offset)
2296                 start += old->extent_offset + old->offset -
2297                          backref->extent_offset;
2298
2299         len = min(backref->extent_offset + backref->num_bytes,
2300                   old->extent_offset + old->offset + old->len);
2301         len -= max(backref->extent_offset, old->extent_offset + old->offset);
2302
2303         ret = btrfs_drop_extents(trans, root, inode, start,
2304                                  start + len, 1);
2305         if (ret)
2306                 goto out_free_path;
2307 again:
2308         key.objectid = btrfs_ino(inode);
2309         key.type = BTRFS_EXTENT_DATA_KEY;
2310         key.offset = start;
2311
2312         path->leave_spinning = 1;
2313         if (merge) {
2314                 struct btrfs_file_extent_item *fi;
2315                 u64 extent_len;
2316                 struct btrfs_key found_key;
2317
2318                 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
2319                 if (ret < 0)
2320                         goto out_free_path;
2321
2322                 path->slots[0]--;
2323                 leaf = path->nodes[0];
2324                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2325
2326                 fi = btrfs_item_ptr(leaf, path->slots[0],
2327                                     struct btrfs_file_extent_item);
2328                 extent_len = btrfs_file_extent_num_bytes(leaf, fi);
2329
2330                 if (extent_len + found_key.offset == start &&
2331                     relink_is_mergable(leaf, fi, new)) {
2332                         btrfs_set_file_extent_num_bytes(leaf, fi,
2333                                                         extent_len + len);
2334                         btrfs_mark_buffer_dirty(leaf);
2335                         inode_add_bytes(inode, len);
2336
2337                         ret = 1;
2338                         goto out_free_path;
2339                 } else {
2340                         merge = false;
2341                         btrfs_release_path(path);
2342                         goto again;
2343                 }
2344         }
2345
2346         ret = btrfs_insert_empty_item(trans, root, path, &key,
2347                                         sizeof(*extent));
2348         if (ret) {
2349                 btrfs_abort_transaction(trans, root, ret);
2350                 goto out_free_path;
2351         }
2352
2353         leaf = path->nodes[0];
2354         item = btrfs_item_ptr(leaf, path->slots[0],
2355                                 struct btrfs_file_extent_item);
2356         btrfs_set_file_extent_disk_bytenr(leaf, item, new->bytenr);
2357         btrfs_set_file_extent_disk_num_bytes(leaf, item, new->disk_len);
2358         btrfs_set_file_extent_offset(leaf, item, start - new->file_pos);
2359         btrfs_set_file_extent_num_bytes(leaf, item, len);
2360         btrfs_set_file_extent_ram_bytes(leaf, item, new->len);
2361         btrfs_set_file_extent_generation(leaf, item, trans->transid);
2362         btrfs_set_file_extent_type(leaf, item, BTRFS_FILE_EXTENT_REG);
2363         btrfs_set_file_extent_compression(leaf, item, new->compress_type);
2364         btrfs_set_file_extent_encryption(leaf, item, 0);
2365         btrfs_set_file_extent_other_encoding(leaf, item, 0);
2366
2367         btrfs_mark_buffer_dirty(leaf);
2368         inode_add_bytes(inode, len);
2369         btrfs_release_path(path);
2370
2371         ret = btrfs_inc_extent_ref(trans, root, new->bytenr,
2372                         new->disk_len, 0,
2373                         backref->root_id, backref->inum,
2374                         new->file_pos, 0);      /* start - extent_offset */
2375         if (ret) {
2376                 btrfs_abort_transaction(trans, root, ret);
2377                 goto out_free_path;
2378         }
2379
2380         ret = 1;
2381 out_free_path:
2382         btrfs_release_path(path);
2383         path->leave_spinning = 0;
2384         btrfs_end_transaction(trans, root);
2385 out_unlock:
2386         unlock_extent_cached(&BTRFS_I(inode)->io_tree, lock_start, lock_end,
2387                              &cached, GFP_NOFS);
2388         iput(inode);
2389         return ret;
2390 }
2391
2392 static void free_sa_defrag_extent(struct new_sa_defrag_extent *new)
2393 {
2394         struct old_sa_defrag_extent *old, *tmp;
2395
2396         if (!new)
2397                 return;
2398
2399         list_for_each_entry_safe(old, tmp, &new->head, list) {
2400                 list_del(&old->list);
2401                 kfree(old);
2402         }
2403         kfree(new);
2404 }
2405
2406 static void relink_file_extents(struct new_sa_defrag_extent *new)
2407 {
2408         struct btrfs_path *path;
2409         struct sa_defrag_extent_backref *backref;
2410         struct sa_defrag_extent_backref *prev = NULL;
2411         struct inode *inode;
2412         struct btrfs_root *root;
2413         struct rb_node *node;
2414         int ret;
2415
2416         inode = new->inode;
2417         root = BTRFS_I(inode)->root;
2418
2419         path = btrfs_alloc_path();
2420         if (!path)
2421                 return;
2422
2423         if (!record_extent_backrefs(path, new)) {
2424                 btrfs_free_path(path);
2425                 goto out;
2426         }
2427         btrfs_release_path(path);
2428
2429         while (1) {
2430                 node = rb_first(&new->root);
2431                 if (!node)
2432                         break;
2433                 rb_erase(node, &new->root);
2434
2435                 backref = rb_entry(node, struct sa_defrag_extent_backref, node);
2436
2437                 ret = relink_extent_backref(path, prev, backref);
2438                 WARN_ON(ret < 0);
2439
2440                 kfree(prev);
2441
2442                 if (ret == 1)
2443                         prev = backref;
2444                 else
2445                         prev = NULL;
2446                 cond_resched();
2447         }
2448         kfree(prev);
2449
2450         btrfs_free_path(path);
2451 out:
2452         free_sa_defrag_extent(new);
2453
2454         atomic_dec(&root->fs_info->defrag_running);
2455         wake_up(&root->fs_info->transaction_wait);
2456 }
2457
2458 static struct new_sa_defrag_extent *
2459 record_old_file_extents(struct inode *inode,
2460                         struct btrfs_ordered_extent *ordered)
2461 {
2462         struct btrfs_root *root = BTRFS_I(inode)->root;
2463         struct btrfs_path *path;
2464         struct btrfs_key key;
2465         struct old_sa_defrag_extent *old;
2466         struct new_sa_defrag_extent *new;
2467         int ret;
2468
2469         new = kmalloc(sizeof(*new), GFP_NOFS);
2470         if (!new)
2471                 return NULL;
2472
2473         new->inode = inode;
2474         new->file_pos = ordered->file_offset;
2475         new->len = ordered->len;
2476         new->bytenr = ordered->start;
2477         new->disk_len = ordered->disk_len;
2478         new->compress_type = ordered->compress_type;
2479         new->root = RB_ROOT;
2480         INIT_LIST_HEAD(&new->head);
2481
2482         path = btrfs_alloc_path();
2483         if (!path)
2484                 goto out_kfree;
2485
2486         key.objectid = btrfs_ino(inode);
2487         key.type = BTRFS_EXTENT_DATA_KEY;
2488         key.offset = new->file_pos;
2489
2490         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2491         if (ret < 0)
2492                 goto out_free_path;
2493         if (ret > 0 && path->slots[0] > 0)
2494                 path->slots[0]--;
2495
2496         /* find out all the old extents for the file range */
2497         while (1) {
2498                 struct btrfs_file_extent_item *extent;
2499                 struct extent_buffer *l;
2500                 int slot;
2501                 u64 num_bytes;
2502                 u64 offset;
2503                 u64 end;
2504                 u64 disk_bytenr;
2505                 u64 extent_offset;
2506
2507                 l = path->nodes[0];
2508                 slot = path->slots[0];
2509
2510                 if (slot >= btrfs_header_nritems(l)) {
2511                         ret = btrfs_next_leaf(root, path);
2512                         if (ret < 0)
2513                                 goto out_free_path;
2514                         else if (ret > 0)
2515                                 break;
2516                         continue;
2517                 }
2518
2519                 btrfs_item_key_to_cpu(l, &key, slot);
2520
2521                 if (key.objectid != btrfs_ino(inode))
2522                         break;
2523                 if (key.type != BTRFS_EXTENT_DATA_KEY)
2524                         break;
2525                 if (key.offset >= new->file_pos + new->len)
2526                         break;
2527
2528                 extent = btrfs_item_ptr(l, slot, struct btrfs_file_extent_item);
2529
2530                 num_bytes = btrfs_file_extent_num_bytes(l, extent);
2531                 if (key.offset + num_bytes < new->file_pos)
2532                         goto next;
2533
2534                 disk_bytenr = btrfs_file_extent_disk_bytenr(l, extent);
2535                 if (!disk_bytenr)
2536                         goto next;
2537
2538                 extent_offset = btrfs_file_extent_offset(l, extent);
2539
2540                 old = kmalloc(sizeof(*old), GFP_NOFS);
2541                 if (!old)
2542                         goto out_free_path;
2543
2544                 offset = max(new->file_pos, key.offset);
2545                 end = min(new->file_pos + new->len, key.offset + num_bytes);
2546
2547                 old->bytenr = disk_bytenr;
2548                 old->extent_offset = extent_offset;
2549                 old->offset = offset - key.offset;
2550                 old->len = end - offset;
2551                 old->new = new;
2552                 old->count = 0;
2553                 list_add_tail(&old->list, &new->head);
2554 next:
2555                 path->slots[0]++;
2556                 cond_resched();
2557         }
2558
2559         btrfs_free_path(path);
2560         atomic_inc(&root->fs_info->defrag_running);
2561
2562         return new;
2563
2564 out_free_path:
2565         btrfs_free_path(path);
2566 out_kfree:
2567         free_sa_defrag_extent(new);
2568         return NULL;
2569 }
2570
2571 /* as ordered data IO finishes, this gets called so we can finish
2572  * an ordered extent if the range of bytes in the file it covers are
2573  * fully written.
2574  */
2575 static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent)
2576 {
2577         struct inode *inode = ordered_extent->inode;
2578         struct btrfs_root *root = BTRFS_I(inode)->root;
2579         struct btrfs_trans_handle *trans = NULL;
2580         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
2581         struct extent_state *cached_state = NULL;
2582         struct new_sa_defrag_extent *new = NULL;
2583         int compress_type = 0;
2584         int ret = 0;
2585         u64 logical_len = ordered_extent->len;
2586         bool nolock;
2587         bool truncated = false;
2588
2589         nolock = btrfs_is_free_space_inode(inode);
2590
2591         if (test_bit(BTRFS_ORDERED_IOERR, &ordered_extent->flags)) {
2592                 ret = -EIO;
2593                 goto out;
2594         }
2595
2596         if (test_bit(BTRFS_ORDERED_TRUNCATED, &ordered_extent->flags)) {
2597                 truncated = true;
2598                 logical_len = ordered_extent->truncated_len;
2599                 /* Truncated the entire extent, don't bother adding */
2600                 if (!logical_len)
2601                         goto out;
2602         }
2603
2604         if (test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags)) {
2605                 BUG_ON(!list_empty(&ordered_extent->list)); /* Logic error */
2606                 btrfs_ordered_update_i_size(inode, 0, ordered_extent);
2607                 if (nolock)
2608                         trans = btrfs_join_transaction_nolock(root);
2609                 else
2610                         trans = btrfs_join_transaction(root);
2611                 if (IS_ERR(trans)) {
2612                         ret = PTR_ERR(trans);
2613                         trans = NULL;
2614                         goto out;
2615                 }
2616                 trans->block_rsv = &root->fs_info->delalloc_block_rsv;
2617                 ret = btrfs_update_inode_fallback(trans, root, inode);
2618                 if (ret) /* -ENOMEM or corruption */
2619                         btrfs_abort_transaction(trans, root, ret);
2620                 goto out;
2621         }
2622
2623         lock_extent_bits(io_tree, ordered_extent->file_offset,
2624                          ordered_extent->file_offset + ordered_extent->len - 1,
2625                          0, &cached_state);
2626
2627         ret = test_range_bit(io_tree, ordered_extent->file_offset,
2628                         ordered_extent->file_offset + ordered_extent->len - 1,
2629                         EXTENT_DEFRAG, 1, cached_state);
2630         if (ret) {
2631                 u64 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
2632                 if (last_snapshot >= BTRFS_I(inode)->generation)
2633                         /* the inode is shared */
2634                         new = record_old_file_extents(inode, ordered_extent);
2635
2636                 clear_extent_bit(io_tree, ordered_extent->file_offset,
2637                         ordered_extent->file_offset + ordered_extent->len - 1,
2638                         EXTENT_DEFRAG, 0, 0, &cached_state, GFP_NOFS);
2639         }
2640
2641         if (nolock)
2642                 trans = btrfs_join_transaction_nolock(root);
2643         else
2644                 trans = btrfs_join_transaction(root);
2645         if (IS_ERR(trans)) {
2646                 ret = PTR_ERR(trans);
2647                 trans = NULL;
2648                 goto out_unlock;
2649         }
2650         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
2651
2652         if (test_bit(BTRFS_ORDERED_COMPRESSED, &ordered_extent->flags))
2653                 compress_type = ordered_extent->compress_type;
2654         if (test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags)) {
2655                 BUG_ON(compress_type);
2656                 ret = btrfs_mark_extent_written(trans, inode,
2657                                                 ordered_extent->file_offset,
2658                                                 ordered_extent->file_offset +
2659                                                 logical_len);
2660         } else {
2661                 BUG_ON(root == root->fs_info->tree_root);
2662                 ret = insert_reserved_file_extent(trans, inode,
2663                                                 ordered_extent->file_offset,
2664                                                 ordered_extent->start,
2665                                                 ordered_extent->disk_len,
2666                                                 logical_len, logical_len,
2667                                                 compress_type, 0, 0,
2668                                                 BTRFS_FILE_EXTENT_REG);
2669         }
2670         unpin_extent_cache(&BTRFS_I(inode)->extent_tree,
2671                            ordered_extent->file_offset, ordered_extent->len,
2672                            trans->transid);
2673         if (ret < 0) {
2674                 btrfs_abort_transaction(trans, root, ret);
2675                 goto out_unlock;
2676         }
2677
2678         add_pending_csums(trans, inode, ordered_extent->file_offset,
2679                           &ordered_extent->list);
2680
2681         btrfs_ordered_update_i_size(inode, 0, ordered_extent);
2682         ret = btrfs_update_inode_fallback(trans, root, inode);
2683         if (ret) { /* -ENOMEM or corruption */
2684                 btrfs_abort_transaction(trans, root, ret);
2685                 goto out_unlock;
2686         }
2687         ret = 0;
2688 out_unlock:
2689         unlock_extent_cached(io_tree, ordered_extent->file_offset,
2690                              ordered_extent->file_offset +
2691                              ordered_extent->len - 1, &cached_state, GFP_NOFS);
2692 out:
2693         if (root != root->fs_info->tree_root)
2694                 btrfs_delalloc_release_metadata(inode, ordered_extent->len);
2695         if (trans)
2696                 btrfs_end_transaction(trans, root);
2697
2698         if (ret || truncated) {
2699                 u64 start, end;
2700
2701                 if (truncated)
2702                         start = ordered_extent->file_offset + logical_len;
2703                 else
2704                         start = ordered_extent->file_offset;
2705                 end = ordered_extent->file_offset + ordered_extent->len - 1;
2706                 clear_extent_uptodate(io_tree, start, end, NULL, GFP_NOFS);
2707
2708                 /* Drop the cache for the part of the extent we didn't write. */
2709                 btrfs_drop_extent_cache(inode, start, end, 0);
2710
2711                 /*
2712                  * If the ordered extent had an IOERR or something else went
2713                  * wrong we need to return the space for this ordered extent
2714                  * back to the allocator.  We only free the extent in the
2715                  * truncated case if we didn't write out the extent at all.
2716                  */
2717                 if ((ret || !logical_len) &&
2718                     !test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags) &&
2719                     !test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags))
2720                         btrfs_free_reserved_extent(root, ordered_extent->start,
2721                                                    ordered_extent->disk_len);
2722         }
2723
2724
2725         /*
2726          * This needs to be done to make sure anybody waiting knows we are done
2727          * updating everything for this ordered extent.
2728          */
2729         btrfs_remove_ordered_extent(inode, ordered_extent);
2730
2731         /* for snapshot-aware defrag */
2732         if (new) {
2733                 if (ret) {
2734                         free_sa_defrag_extent(new);
2735                         atomic_dec(&root->fs_info->defrag_running);
2736                 } else {
2737                         relink_file_extents(new);
2738                 }
2739         }
2740
2741         /* once for us */
2742         btrfs_put_ordered_extent(ordered_extent);
2743         /* once for the tree */
2744         btrfs_put_ordered_extent(ordered_extent);
2745
2746         return ret;
2747 }
2748
2749 static void finish_ordered_fn(struct btrfs_work *work)
2750 {
2751         struct btrfs_ordered_extent *ordered_extent;
2752         ordered_extent = container_of(work, struct btrfs_ordered_extent, work);
2753         btrfs_finish_ordered_io(ordered_extent);
2754 }
2755
2756 static int btrfs_writepage_end_io_hook(struct page *page, u64 start, u64 end,
2757                                 struct extent_state *state, int uptodate)
2758 {
2759         struct inode *inode = page->mapping->host;
2760         struct btrfs_root *root = BTRFS_I(inode)->root;
2761         struct btrfs_ordered_extent *ordered_extent = NULL;
2762         struct btrfs_workers *workers;
2763
2764         trace_btrfs_writepage_end_io_hook(page, start, end, uptodate);
2765
2766         ClearPagePrivate2(page);
2767         if (!btrfs_dec_test_ordered_pending(inode, &ordered_extent, start,
2768                                             end - start + 1, uptodate))
2769                 return 0;
2770
2771         ordered_extent->work.func = finish_ordered_fn;
2772         ordered_extent->work.flags = 0;
2773
2774         if (btrfs_is_free_space_inode(inode))
2775                 workers = &root->fs_info->endio_freespace_worker;
2776         else
2777                 workers = &root->fs_info->endio_write_workers;
2778         btrfs_queue_worker(workers, &ordered_extent->work);
2779
2780         return 0;
2781 }
2782
2783 /*
2784  * when reads are done, we need to check csums to verify the data is correct
2785  * if there's a match, we allow the bio to finish.  If not, the code in
2786  * extent_io.c will try to find good copies for us.
2787  */
2788 static int btrfs_readpage_end_io_hook(struct btrfs_io_bio *io_bio,
2789                                       u64 phy_offset, struct page *page,
2790                                       u64 start, u64 end, int mirror)
2791 {
2792         size_t offset = start - page_offset(page);
2793         struct inode *inode = page->mapping->host;
2794         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
2795         char *kaddr;
2796         struct btrfs_root *root = BTRFS_I(inode)->root;
2797         u32 csum_expected;
2798         u32 csum = ~(u32)0;
2799         static DEFINE_RATELIMIT_STATE(_rs, DEFAULT_RATELIMIT_INTERVAL,
2800                                       DEFAULT_RATELIMIT_BURST);
2801
2802         if (PageChecked(page)) {
2803                 ClearPageChecked(page);
2804                 goto good;
2805         }
2806
2807         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)
2808                 goto good;
2809
2810         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID &&
2811             test_range_bit(io_tree, start, end, EXTENT_NODATASUM, 1, NULL)) {
2812                 clear_extent_bits(io_tree, start, end, EXTENT_NODATASUM,
2813                                   GFP_NOFS);
2814                 return 0;
2815         }
2816
2817         phy_offset >>= inode->i_sb->s_blocksize_bits;
2818         csum_expected = *(((u32 *)io_bio->csum) + phy_offset);
2819
2820         kaddr = kmap_atomic(page);
2821         csum = btrfs_csum_data(kaddr + offset, csum,  end - start + 1);
2822         btrfs_csum_final(csum, (char *)&csum);
2823         if (csum != csum_expected)
2824                 goto zeroit;
2825
2826         kunmap_atomic(kaddr);
2827 good:
2828         return 0;
2829
2830 zeroit:
2831         if (__ratelimit(&_rs))
2832                 btrfs_info(root->fs_info, "csum failed ino %llu off %llu csum %u expected csum %u",
2833                         btrfs_ino(page->mapping->host), start, csum, csum_expected);
2834         memset(kaddr + offset, 1, end - start + 1);
2835         flush_dcache_page(page);
2836         kunmap_atomic(kaddr);
2837         if (csum_expected == 0)
2838                 return 0;
2839         return -EIO;
2840 }
2841
2842 struct delayed_iput {
2843         struct list_head list;
2844         struct inode *inode;
2845 };
2846
2847 /* JDM: If this is fs-wide, why can't we add a pointer to
2848  * btrfs_inode instead and avoid the allocation? */
2849 void btrfs_add_delayed_iput(struct inode *inode)
2850 {
2851         struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
2852         struct delayed_iput *delayed;
2853
2854         if (atomic_add_unless(&inode->i_count, -1, 1))
2855                 return;
2856
2857         delayed = kmalloc(sizeof(*delayed), GFP_NOFS | __GFP_NOFAIL);
2858         delayed->inode = inode;
2859
2860         spin_lock(&fs_info->delayed_iput_lock);
2861         list_add_tail(&delayed->list, &fs_info->delayed_iputs);
2862         spin_unlock(&fs_info->delayed_iput_lock);
2863 }
2864
2865 void btrfs_run_delayed_iputs(struct btrfs_root *root)
2866 {
2867         LIST_HEAD(list);
2868         struct btrfs_fs_info *fs_info = root->fs_info;
2869         struct delayed_iput *delayed;
2870         int empty;
2871
2872         spin_lock(&fs_info->delayed_iput_lock);
2873         empty = list_empty(&fs_info->delayed_iputs);
2874         spin_unlock(&fs_info->delayed_iput_lock);
2875         if (empty)
2876                 return;
2877
2878         spin_lock(&fs_info->delayed_iput_lock);
2879         list_splice_init(&fs_info->delayed_iputs, &list);
2880         spin_unlock(&fs_info->delayed_iput_lock);
2881
2882         while (!list_empty(&list)) {
2883                 delayed = list_entry(list.next, struct delayed_iput, list);
2884                 list_del(&delayed->list);
2885                 iput(delayed->inode);
2886                 kfree(delayed);
2887         }
2888 }
2889
2890 /*
2891  * This is called in transaction commit time. If there are no orphan
2892  * files in the subvolume, it removes orphan item and frees block_rsv
2893  * structure.
2894  */
2895 void btrfs_orphan_commit_root(struct btrfs_trans_handle *trans,
2896                               struct btrfs_root *root)
2897 {
2898         struct btrfs_block_rsv *block_rsv;
2899         int ret;
2900
2901         if (atomic_read(&root->orphan_inodes) ||
2902             root->orphan_cleanup_state != ORPHAN_CLEANUP_DONE)
2903                 return;
2904
2905         spin_lock(&root->orphan_lock);
2906         if (atomic_read(&root->orphan_inodes)) {
2907                 spin_unlock(&root->orphan_lock);
2908                 return;
2909         }
2910
2911         if (root->orphan_cleanup_state != ORPHAN_CLEANUP_DONE) {
2912                 spin_unlock(&root->orphan_lock);
2913                 return;
2914         }
2915
2916         block_rsv = root->orphan_block_rsv;
2917         root->orphan_block_rsv = NULL;
2918         spin_unlock(&root->orphan_lock);
2919
2920         if (root->orphan_item_inserted &&
2921             btrfs_root_refs(&root->root_item) > 0) {
2922                 ret = btrfs_del_orphan_item(trans, root->fs_info->tree_root,
2923                                             root->root_key.objectid);
2924                 if (ret)
2925                         btrfs_abort_transaction(trans, root, ret);
2926                 else
2927                         root->orphan_item_inserted = 0;
2928         }
2929
2930         if (block_rsv) {
2931                 WARN_ON(block_rsv->size > 0);
2932                 btrfs_free_block_rsv(root, block_rsv);
2933         }
2934 }
2935
2936 /*
2937  * This creates an orphan entry for the given inode in case something goes
2938  * wrong in the middle of an unlink/truncate.
2939  *
2940  * NOTE: caller of this function should reserve 5 units of metadata for
2941  *       this function.
2942  */
2943 int btrfs_orphan_add(struct btrfs_trans_handle *trans, struct inode *inode)
2944 {
2945         struct btrfs_root *root = BTRFS_I(inode)->root;
2946         struct btrfs_block_rsv *block_rsv = NULL;
2947         int reserve = 0;
2948         int insert = 0;
2949         int ret;
2950
2951         if (!root->orphan_block_rsv) {
2952                 block_rsv = btrfs_alloc_block_rsv(root, BTRFS_BLOCK_RSV_TEMP);
2953                 if (!block_rsv)
2954                         return -ENOMEM;
2955         }
2956
2957         spin_lock(&root->orphan_lock);
2958         if (!root->orphan_block_rsv) {
2959                 root->orphan_block_rsv = block_rsv;
2960         } else if (block_rsv) {
2961                 btrfs_free_block_rsv(root, block_rsv);
2962                 block_rsv = NULL;
2963         }
2964
2965         if (!test_and_set_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
2966                               &BTRFS_I(inode)->runtime_flags)) {
2967 #if 0
2968                 /*
2969                  * For proper ENOSPC handling, we should do orphan
2970                  * cleanup when mounting. But this introduces backward
2971                  * compatibility issue.
2972                  */
2973                 if (!xchg(&root->orphan_item_inserted, 1))
2974                         insert = 2;
2975                 else
2976                         insert = 1;
2977 #endif
2978                 insert = 1;
2979                 atomic_inc(&root->orphan_inodes);
2980         }
2981
2982         if (!test_and_set_bit(BTRFS_INODE_ORPHAN_META_RESERVED,
2983                               &BTRFS_I(inode)->runtime_flags))
2984                 reserve = 1;
2985         spin_unlock(&root->orphan_lock);
2986
2987         /* grab metadata reservation from transaction handle */
2988         if (reserve) {
2989                 ret = btrfs_orphan_reserve_metadata(trans, inode);
2990                 BUG_ON(ret); /* -ENOSPC in reservation; Logic error? JDM */
2991         }
2992
2993         /* insert an orphan item to track this unlinked/truncated file */
2994         if (insert >= 1) {
2995                 ret = btrfs_insert_orphan_item(trans, root, btrfs_ino(inode));
2996                 if (ret) {
2997                         atomic_dec(&root->orphan_inodes);
2998                         if (reserve) {
2999                                 clear_bit(BTRFS_INODE_ORPHAN_META_RESERVED,
3000                                           &BTRFS_I(inode)->runtime_flags);
3001                                 btrfs_orphan_release_metadata(inode);
3002                         }
3003                         if (ret != -EEXIST) {
3004                                 clear_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3005                                           &BTRFS_I(inode)->runtime_flags);
3006                                 btrfs_abort_transaction(trans, root, ret);
3007                                 return ret;
3008                         }
3009                 }
3010                 ret = 0;
3011         }
3012
3013         /* insert an orphan item to track subvolume contains orphan files */
3014         if (insert >= 2) {
3015                 ret = btrfs_insert_orphan_item(trans, root->fs_info->tree_root,
3016                                                root->root_key.objectid);
3017                 if (ret && ret != -EEXIST) {
3018                         btrfs_abort_transaction(trans, root, ret);
3019                         return ret;
3020                 }
3021         }
3022         return 0;
3023 }
3024
3025 /*
3026  * We have done the truncate/delete so we can go ahead and remove the orphan
3027  * item for this particular inode.
3028  */
3029 static int btrfs_orphan_del(struct btrfs_trans_handle *trans,
3030                             struct inode *inode)
3031 {
3032         struct btrfs_root *root = BTRFS_I(inode)->root;
3033         int delete_item = 0;
3034         int release_rsv = 0;
3035         int ret = 0;
3036
3037         spin_lock(&root->orphan_lock);
3038         if (test_and_clear_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3039                                &BTRFS_I(inode)->runtime_flags))
3040                 delete_item = 1;
3041
3042         if (test_and_clear_bit(BTRFS_INODE_ORPHAN_META_RESERVED,
3043                                &BTRFS_I(inode)->runtime_flags))
3044                 release_rsv = 1;
3045         spin_unlock(&root->orphan_lock);
3046
3047         if (delete_item) {
3048                 atomic_dec(&root->orphan_inodes);
3049                 if (trans)
3050                         ret = btrfs_del_orphan_item(trans, root,
3051                                                     btrfs_ino(inode));
3052         }
3053
3054         if (release_rsv)
3055                 btrfs_orphan_release_metadata(inode);
3056
3057         return ret;
3058 }
3059
3060 /*
3061  * this cleans up any orphans that may be left on the list from the last use
3062  * of this root.
3063  */
3064 int btrfs_orphan_cleanup(struct btrfs_root *root)
3065 {
3066         struct btrfs_path *path;
3067         struct extent_buffer *leaf;
3068         struct btrfs_key key, found_key;
3069         struct btrfs_trans_handle *trans;
3070         struct inode *inode;
3071         u64 last_objectid = 0;
3072         int ret = 0, nr_unlink = 0, nr_truncate = 0;
3073
3074         if (cmpxchg(&root->orphan_cleanup_state, 0, ORPHAN_CLEANUP_STARTED))
3075                 return 0;
3076
3077         path = btrfs_alloc_path();
3078         if (!path) {
3079                 ret = -ENOMEM;
3080                 goto out;
3081         }
3082         path->reada = -1;
3083
3084         key.objectid = BTRFS_ORPHAN_OBJECTID;
3085         btrfs_set_key_type(&key, BTRFS_ORPHAN_ITEM_KEY);
3086         key.offset = (u64)-1;
3087
3088         while (1) {
3089                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3090                 if (ret < 0)
3091                         goto out;
3092
3093                 /*
3094                  * if ret == 0 means we found what we were searching for, which
3095                  * is weird, but possible, so only screw with path if we didn't
3096                  * find the key and see if we have stuff that matches
3097                  */
3098                 if (ret > 0) {
3099                         ret = 0;
3100                         if (path->slots[0] == 0)
3101                                 break;
3102                         path->slots[0]--;
3103                 }
3104
3105                 /* pull out the item */
3106                 leaf = path->nodes[0];
3107                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3108
3109                 /* make sure the item matches what we want */
3110                 if (found_key.objectid != BTRFS_ORPHAN_OBJECTID)
3111                         break;
3112                 if (btrfs_key_type(&found_key) != BTRFS_ORPHAN_ITEM_KEY)
3113                         break;
3114
3115                 /* release the path since we're done with it */
3116                 btrfs_release_path(path);
3117
3118                 /*
3119                  * this is where we are basically btrfs_lookup, without the
3120                  * crossing root thing.  we store the inode number in the
3121                  * offset of the orphan item.
3122                  */
3123
3124                 if (found_key.offset == last_objectid) {
3125                         btrfs_err(root->fs_info,
3126                                 "Error removing orphan entry, stopping orphan cleanup");
3127                         ret = -EINVAL;
3128                         goto out;
3129                 }
3130
3131                 last_objectid = found_key.offset;
3132
3133                 found_key.objectid = found_key.offset;
3134                 found_key.type = BTRFS_INODE_ITEM_KEY;
3135                 found_key.offset = 0;
3136                 inode = btrfs_iget(root->fs_info->sb, &found_key, root, NULL);
3137                 ret = PTR_ERR_OR_ZERO(inode);
3138                 if (ret && ret != -ESTALE)
3139                         goto out;
3140
3141                 if (ret == -ESTALE && root == root->fs_info->tree_root) {
3142                         struct btrfs_root *dead_root;
3143                         struct btrfs_fs_info *fs_info = root->fs_info;
3144                         int is_dead_root = 0;
3145
3146                         /*
3147                          * this is an orphan in the tree root. Currently these
3148                          * could come from 2 sources:
3149                          *  a) a snapshot deletion in progress
3150                          *  b) a free space cache inode
3151                          * We need to distinguish those two, as the snapshot
3152                          * orphan must not get deleted.
3153                          * find_dead_roots already ran before us, so if this
3154                          * is a snapshot deletion, we should find the root
3155                          * in the dead_roots list
3156                          */
3157                         spin_lock(&fs_info->trans_lock);
3158                         list_for_each_entry(dead_root, &fs_info->dead_roots,
3159                                             root_list) {
3160                                 if (dead_root->root_key.objectid ==
3161                                     found_key.objectid) {
3162                                         is_dead_root = 1;
3163                                         break;
3164                                 }
3165                         }
3166                         spin_unlock(&fs_info->trans_lock);
3167                         if (is_dead_root) {
3168                                 /* prevent this orphan from being found again */
3169                                 key.offset = found_key.objectid - 1;
3170                                 continue;
3171                         }
3172                 }
3173                 /*
3174                  * Inode is already gone but the orphan item is still there,
3175                  * kill the orphan item.
3176                  */
3177                 if (ret == -ESTALE) {
3178                         trans = btrfs_start_transaction(root, 1);
3179                         if (IS_ERR(trans)) {
3180                                 ret = PTR_ERR(trans);
3181                                 goto out;
3182                         }
3183                         btrfs_debug(root->fs_info, "auto deleting %Lu",
3184                                 found_key.objectid);
3185                         ret = btrfs_del_orphan_item(trans, root,
3186                                                     found_key.objectid);
3187                         btrfs_end_transaction(trans, root);
3188                         if (ret)
3189                                 goto out;
3190                         continue;
3191                 }
3192
3193                 /*
3194                  * add this inode to the orphan list so btrfs_orphan_del does
3195                  * the proper thing when we hit it
3196                  */
3197                 set_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
3198                         &BTRFS_I(inode)->runtime_flags);
3199                 atomic_inc(&root->orphan_inodes);
3200
3201                 /* if we have links, this was a truncate, lets do that */
3202                 if (inode->i_nlink) {
3203                         if (WARN_ON(!S_ISREG(inode->i_mode))) {
3204                                 iput(inode);
3205                                 continue;
3206                         }
3207                         nr_truncate++;
3208
3209                         /* 1 for the orphan item deletion. */
3210                         trans = btrfs_start_transaction(root, 1);
3211                         if (IS_ERR(trans)) {
3212                                 iput(inode);
3213                                 ret = PTR_ERR(trans);
3214                                 goto out;
3215                         }
3216                         ret = btrfs_orphan_add(trans, inode);
3217                         btrfs_end_transaction(trans, root);
3218                         if (ret) {
3219                                 iput(inode);
3220                                 goto out;
3221                         }
3222
3223                         ret = btrfs_truncate(inode);
3224                         if (ret)
3225                                 btrfs_orphan_del(NULL, inode);
3226                 } else {
3227                         nr_unlink++;
3228                 }
3229
3230                 /* this will do delete_inode and everything for us */
3231                 iput(inode);
3232                 if (ret)
3233                         goto out;
3234         }
3235         /* release the path since we're done with it */
3236         btrfs_release_path(path);
3237
3238         root->orphan_cleanup_state = ORPHAN_CLEANUP_DONE;
3239
3240         if (root->orphan_block_rsv)
3241                 btrfs_block_rsv_release(root, root->orphan_block_rsv,
3242                                         (u64)-1);
3243
3244         if (root->orphan_block_rsv || root->orphan_item_inserted) {
3245                 trans = btrfs_join_transaction(root);
3246                 if (!IS_ERR(trans))
3247                         btrfs_end_transaction(trans, root);
3248         }
3249
3250         if (nr_unlink)
3251                 btrfs_debug(root->fs_info, "unlinked %d orphans", nr_unlink);
3252         if (nr_truncate)
3253                 btrfs_debug(root->fs_info, "truncated %d orphans", nr_truncate);
3254
3255 out:
3256         if (ret)
3257                 btrfs_crit(root->fs_info,
3258                         "could not do orphan cleanup %d", ret);
3259         btrfs_free_path(path);
3260         return ret;
3261 }
3262
3263 /*
3264  * very simple check to peek ahead in the leaf looking for xattrs.  If we
3265  * don't find any xattrs, we know there can't be any acls.
3266  *
3267  * slot is the slot the inode is in, objectid is the objectid of the inode
3268  */
3269 static noinline int acls_after_inode_item(struct extent_buffer *leaf,
3270                                           int slot, u64 objectid,
3271                                           int *first_xattr_slot)
3272 {
3273         u32 nritems = btrfs_header_nritems(leaf);
3274         struct btrfs_key found_key;
3275         static u64 xattr_access = 0;
3276         static u64 xattr_default = 0;
3277         int scanned = 0;
3278
3279         if (!xattr_access) {
3280                 xattr_access = btrfs_name_hash(POSIX_ACL_XATTR_ACCESS,
3281                                         strlen(POSIX_ACL_XATTR_ACCESS));
3282                 xattr_default = btrfs_name_hash(POSIX_ACL_XATTR_DEFAULT,
3283                                         strlen(POSIX_ACL_XATTR_DEFAULT));
3284         }
3285
3286         slot++;
3287         *first_xattr_slot = -1;
3288         while (slot < nritems) {
3289                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
3290
3291                 /* we found a different objectid, there must not be acls */
3292                 if (found_key.objectid != objectid)
3293                         return 0;
3294
3295                 /* we found an xattr, assume we've got an acl */
3296                 if (found_key.type == BTRFS_XATTR_ITEM_KEY) {
3297                         if (*first_xattr_slot == -1)
3298                                 *first_xattr_slot = slot;
3299                         if (found_key.offset == xattr_access ||
3300                             found_key.offset == xattr_default)
3301                                 return 1;
3302                 }
3303
3304                 /*
3305                  * we found a key greater than an xattr key, there can't
3306                  * be any acls later on
3307                  */
3308                 if (found_key.type > BTRFS_XATTR_ITEM_KEY)
3309                         return 0;
3310
3311                 slot++;
3312                 scanned++;
3313
3314                 /*
3315                  * it goes inode, inode backrefs, xattrs, extents,
3316                  * so if there are a ton of hard links to an inode there can
3317                  * be a lot of backrefs.  Don't waste time searching too hard,
3318                  * this is just an optimization
3319                  */
3320                 if (scanned >= 8)
3321                         break;
3322         }
3323         /* we hit the end of the leaf before we found an xattr or
3324          * something larger than an xattr.  We have to assume the inode
3325          * has acls
3326          */
3327         if (*first_xattr_slot == -1)
3328                 *first_xattr_slot = slot;
3329         return 1;
3330 }
3331
3332 /*
3333  * read an inode from the btree into the in-memory inode
3334  */
3335 static void btrfs_read_locked_inode(struct inode *inode)
3336 {
3337         struct btrfs_path *path;
3338         struct extent_buffer *leaf;
3339         struct btrfs_inode_item *inode_item;
3340         struct btrfs_timespec *tspec;
3341         struct btrfs_root *root = BTRFS_I(inode)->root;
3342         struct btrfs_key location;
3343         unsigned long ptr;
3344         int maybe_acls;
3345         u32 rdev;
3346         int ret;
3347         bool filled = false;
3348         int first_xattr_slot;
3349
3350         ret = btrfs_fill_inode(inode, &rdev);
3351         if (!ret)
3352                 filled = true;
3353
3354         path = btrfs_alloc_path();
3355         if (!path)
3356                 goto make_bad;
3357
3358         memcpy(&location, &BTRFS_I(inode)->location, sizeof(location));
3359
3360         ret = btrfs_lookup_inode(NULL, root, path, &location, 0);
3361         if (ret)
3362                 goto make_bad;
3363
3364         leaf = path->nodes[0];
3365
3366         if (filled)
3367                 goto cache_index;
3368
3369         inode_item = btrfs_item_ptr(leaf, path->slots[0],
3370                                     struct btrfs_inode_item);
3371         inode->i_mode = btrfs_inode_mode(leaf, inode_item);
3372         set_nlink(inode, btrfs_inode_nlink(leaf, inode_item));
3373         i_uid_write(inode, btrfs_inode_uid(leaf, inode_item));
3374         i_gid_write(inode, btrfs_inode_gid(leaf, inode_item));
3375         btrfs_i_size_write(inode, btrfs_inode_size(leaf, inode_item));
3376
3377         tspec = btrfs_inode_atime(inode_item);
3378         inode->i_atime.tv_sec = btrfs_timespec_sec(leaf, tspec);
3379         inode->i_atime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
3380
3381         tspec = btrfs_inode_mtime(inode_item);
3382         inode->i_mtime.tv_sec = btrfs_timespec_sec(leaf, tspec);
3383         inode->i_mtime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
3384
3385         tspec = btrfs_inode_ctime(inode_item);
3386         inode->i_ctime.tv_sec = btrfs_timespec_sec(leaf, tspec);
3387         inode->i_ctime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
3388
3389         inode_set_bytes(inode, btrfs_inode_nbytes(leaf, inode_item));
3390         BTRFS_I(inode)->generation = btrfs_inode_generation(leaf, inode_item);
3391         BTRFS_I(inode)->last_trans = btrfs_inode_transid(leaf, inode_item);
3392
3393         /*
3394          * If we were modified in the current generation and evicted from memory
3395          * and then re-read we need to do a full sync since we don't have any
3396          * idea about which extents were modified before we were evicted from
3397          * cache.
3398          */
3399         if (BTRFS_I(inode)->last_trans == root->fs_info->generation)
3400                 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
3401                         &BTRFS_I(inode)->runtime_flags);
3402
3403         inode->i_version = btrfs_inode_sequence(leaf, inode_item);
3404         inode->i_generation = BTRFS_I(inode)->generation;
3405         inode->i_rdev = 0;
3406         rdev = btrfs_inode_rdev(leaf, inode_item);
3407
3408         BTRFS_I(inode)->index_cnt = (u64)-1;
3409         BTRFS_I(inode)->flags = btrfs_inode_flags(leaf, inode_item);
3410
3411 cache_index:
3412         path->slots[0]++;
3413         if (inode->i_nlink != 1 ||
3414             path->slots[0] >= btrfs_header_nritems(leaf))
3415                 goto cache_acl;
3416
3417         btrfs_item_key_to_cpu(leaf, &location, path->slots[0]);
3418         if (location.objectid != btrfs_ino(inode))
3419                 goto cache_acl;
3420
3421         ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
3422         if (location.type == BTRFS_INODE_REF_KEY) {
3423                 struct btrfs_inode_ref *ref;
3424
3425                 ref = (struct btrfs_inode_ref *)ptr;
3426                 BTRFS_I(inode)->dir_index = btrfs_inode_ref_index(leaf, ref);
3427         } else if (location.type == BTRFS_INODE_EXTREF_KEY) {
3428                 struct btrfs_inode_extref *extref;
3429
3430                 extref = (struct btrfs_inode_extref *)ptr;
3431                 BTRFS_I(inode)->dir_index = btrfs_inode_extref_index(leaf,
3432                                                                      extref);
3433         }
3434 cache_acl:
3435         /*
3436          * try to precache a NULL acl entry for files that don't have
3437          * any xattrs or acls
3438          */
3439         maybe_acls = acls_after_inode_item(leaf, path->slots[0],
3440                                            btrfs_ino(inode), &first_xattr_slot);
3441         if (first_xattr_slot != -1) {
3442                 path->slots[0] = first_xattr_slot;
3443                 ret = btrfs_load_inode_props(inode, path);
3444                 if (ret)
3445                         btrfs_err(root->fs_info,
3446                                   "error loading props for ino %llu (root %llu): %d\n",
3447                                   btrfs_ino(inode),
3448                                   root->root_key.objectid, ret);
3449         }
3450         btrfs_free_path(path);
3451
3452         if (!maybe_acls)
3453                 cache_no_acl(inode);
3454
3455         switch (inode->i_mode & S_IFMT) {
3456         case S_IFREG:
3457                 inode->i_mapping->a_ops = &btrfs_aops;
3458                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
3459                 BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
3460                 inode->i_fop = &btrfs_file_operations;
3461                 inode->i_op = &btrfs_file_inode_operations;
3462                 break;
3463         case S_IFDIR:
3464                 inode->i_fop = &btrfs_dir_file_operations;
3465                 if (root == root->fs_info->tree_root)
3466                         inode->i_op = &btrfs_dir_ro_inode_operations;
3467                 else
3468                         inode->i_op = &btrfs_dir_inode_operations;
3469                 break;
3470         case S_IFLNK:
3471                 inode->i_op = &btrfs_symlink_inode_operations;
3472                 inode->i_mapping->a_ops = &btrfs_symlink_aops;
3473                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
3474                 break;
3475         default:
3476                 inode->i_op = &btrfs_special_inode_operations;
3477                 init_special_inode(inode, inode->i_mode, rdev);
3478                 break;
3479         }
3480
3481         btrfs_update_iflags(inode);
3482         return;
3483
3484 make_bad:
3485         btrfs_free_path(path);
3486         make_bad_inode(inode);
3487 }
3488
3489 /*
3490  * given a leaf and an inode, copy the inode fields into the leaf
3491  */
3492 static void fill_inode_item(struct btrfs_trans_handle *trans,
3493                             struct extent_buffer *leaf,
3494                             struct btrfs_inode_item *item,
3495                             struct inode *inode)
3496 {
3497         struct btrfs_map_token token;
3498
3499         btrfs_init_map_token(&token);
3500
3501         btrfs_set_token_inode_uid(leaf, item, i_uid_read(inode), &token);
3502         btrfs_set_token_inode_gid(leaf, item, i_gid_read(inode), &token);
3503         btrfs_set_token_inode_size(leaf, item, BTRFS_I(inode)->disk_i_size,
3504                                    &token);
3505         btrfs_set_token_inode_mode(leaf, item, inode->i_mode, &token);
3506         btrfs_set_token_inode_nlink(leaf, item, inode->i_nlink, &token);
3507
3508         btrfs_set_token_timespec_sec(leaf, btrfs_inode_atime(item),
3509                                      inode->i_atime.tv_sec, &token);
3510         btrfs_set_token_timespec_nsec(leaf, btrfs_inode_atime(item),
3511                                       inode->i_atime.tv_nsec, &token);
3512
3513         btrfs_set_token_timespec_sec(leaf, btrfs_inode_mtime(item),
3514                                      inode->i_mtime.tv_sec, &token);
3515         btrfs_set_token_timespec_nsec(leaf, btrfs_inode_mtime(item),
3516                                       inode->i_mtime.tv_nsec, &token);
3517
3518         btrfs_set_token_timespec_sec(leaf, btrfs_inode_ctime(item),
3519                                      inode->i_ctime.tv_sec, &token);
3520         btrfs_set_token_timespec_nsec(leaf, btrfs_inode_ctime(item),
3521                                       inode->i_ctime.tv_nsec, &token);
3522
3523         btrfs_set_token_inode_nbytes(leaf, item, inode_get_bytes(inode),
3524                                      &token);
3525         btrfs_set_token_inode_generation(leaf, item, BTRFS_I(inode)->generation,
3526                                          &token);
3527         btrfs_set_token_inode_sequence(leaf, item, inode->i_version, &token);
3528         btrfs_set_token_inode_transid(leaf, item, trans->transid, &token);
3529         btrfs_set_token_inode_rdev(leaf, item, inode->i_rdev, &token);
3530         btrfs_set_token_inode_flags(leaf, item, BTRFS_I(inode)->flags, &token);
3531         btrfs_set_token_inode_block_group(leaf, item, 0, &token);
3532 }
3533
3534 /*
3535  * copy everything in the in-memory inode into the btree.
3536  */
3537 static noinline int btrfs_update_inode_item(struct btrfs_trans_handle *trans,
3538                                 struct btrfs_root *root, struct inode *inode)
3539 {
3540         struct btrfs_inode_item *inode_item;
3541         struct btrfs_path *path;
3542         struct extent_buffer *leaf;
3543         int ret;
3544
3545         path = btrfs_alloc_path();
3546         if (!path)
3547                 return -ENOMEM;
3548
3549         path->leave_spinning = 1;
3550         ret = btrfs_lookup_inode(trans, root, path, &BTRFS_I(inode)->location,
3551                                  1);
3552         if (ret) {
3553                 if (ret > 0)
3554                         ret = -ENOENT;
3555                 goto failed;
3556         }
3557
3558         leaf = path->nodes[0];
3559         inode_item = btrfs_item_ptr(leaf, path->slots[0],
3560                                     struct btrfs_inode_item);
3561
3562         fill_inode_item(trans, leaf, inode_item, inode);
3563         btrfs_mark_buffer_dirty(leaf);
3564         btrfs_set_inode_last_trans(trans, inode);
3565         ret = 0;
3566 failed:
3567         btrfs_free_path(path);
3568         return ret;
3569 }
3570
3571 /*
3572  * copy everything in the in-memory inode into the btree.
3573  */
3574 noinline int btrfs_update_inode(struct btrfs_trans_handle *trans,
3575                                 struct btrfs_root *root, struct inode *inode)
3576 {
3577         int ret;
3578
3579         /*
3580          * If the inode is a free space inode, we can deadlock during commit
3581          * if we put it into the delayed code.
3582          *
3583          * The data relocation inode should also be directly updated
3584          * without delay
3585          */
3586         if (!btrfs_is_free_space_inode(inode)
3587             && root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID) {
3588                 btrfs_update_root_times(trans, root);
3589
3590                 ret = btrfs_delayed_update_inode(trans, root, inode);
3591                 if (!ret)
3592                         btrfs_set_inode_last_trans(trans, inode);
3593                 return ret;
3594         }
3595
3596         return btrfs_update_inode_item(trans, root, inode);
3597 }
3598
3599 noinline int btrfs_update_inode_fallback(struct btrfs_trans_handle *trans,
3600                                          struct btrfs_root *root,
3601                                          struct inode *inode)
3602 {
3603         int ret;
3604
3605         ret = btrfs_update_inode(trans, root, inode);
3606         if (ret == -ENOSPC)
3607                 return btrfs_update_inode_item(trans, root, inode);
3608         return ret;
3609 }
3610
3611 /*
3612  * unlink helper that gets used here in inode.c and in the tree logging
3613  * recovery code.  It remove a link in a directory with a given name, and
3614  * also drops the back refs in the inode to the directory
3615  */
3616 static int __btrfs_unlink_inode(struct btrfs_trans_handle *trans,
3617                                 struct btrfs_root *root,
3618                                 struct inode *dir, struct inode *inode,
3619                                 const char *name, int name_len)
3620 {
3621         struct btrfs_path *path;
3622         int ret = 0;
3623         struct extent_buffer *leaf;
3624         struct btrfs_dir_item *di;
3625         struct btrfs_key key;
3626         u64 index;
3627         u64 ino = btrfs_ino(inode);
3628         u64 dir_ino = btrfs_ino(dir);
3629
3630         path = btrfs_alloc_path();
3631         if (!path) {
3632                 ret = -ENOMEM;
3633                 goto out;
3634         }
3635
3636         path->leave_spinning = 1;
3637         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
3638                                     name, name_len, -1);
3639         if (IS_ERR(di)) {
3640                 ret = PTR_ERR(di);
3641                 goto err;
3642         }
3643         if (!di) {
3644                 ret = -ENOENT;
3645                 goto err;
3646         }
3647         leaf = path->nodes[0];
3648         btrfs_dir_item_key_to_cpu(leaf, di, &key);
3649         ret = btrfs_delete_one_dir_name(trans, root, path, di);
3650         if (ret)
3651                 goto err;
3652         btrfs_release_path(path);
3653
3654         /*
3655          * If we don't have dir index, we have to get it by looking up
3656          * the inode ref, since we get the inode ref, remove it directly,
3657          * it is unnecessary to do delayed deletion.
3658          *
3659          * But if we have dir index, needn't search inode ref to get it.
3660          * Since the inode ref is close to the inode item, it is better
3661          * that we delay to delete it, and just do this deletion when
3662          * we update the inode item.
3663          */
3664         if (BTRFS_I(inode)->dir_index) {
3665                 ret = btrfs_delayed_delete_inode_ref(inode);
3666                 if (!ret) {
3667                         index = BTRFS_I(inode)->dir_index;
3668                         goto skip_backref;
3669                 }
3670         }
3671
3672         ret = btrfs_del_inode_ref(trans, root, name, name_len, ino,
3673                                   dir_ino, &index);
3674         if (ret) {
3675                 btrfs_info(root->fs_info,
3676                         "failed to delete reference to %.*s, inode %llu parent %llu",
3677                         name_len, name, ino, dir_ino);
3678                 btrfs_abort_transaction(trans, root, ret);
3679                 goto err;
3680         }
3681 skip_backref:
3682         ret = btrfs_delete_delayed_dir_index(trans, root, dir, index);
3683         if (ret) {
3684                 btrfs_abort_transaction(trans, root, ret);
3685                 goto err;
3686         }
3687
3688         ret = btrfs_del_inode_ref_in_log(trans, root, name, name_len,
3689                                          inode, dir_ino);
3690         if (ret != 0 && ret != -ENOENT) {
3691                 btrfs_abort_transaction(trans, root, ret);
3692                 goto err;
3693         }
3694
3695         ret = btrfs_del_dir_entries_in_log(trans, root, name, name_len,
3696                                            dir, index);
3697         if (ret == -ENOENT)
3698                 ret = 0;
3699         else if (ret)
3700                 btrfs_abort_transaction(trans, root, ret);
3701 err:
3702         btrfs_free_path(path);
3703         if (ret)
3704                 goto out;
3705
3706         btrfs_i_size_write(dir, dir->i_size - name_len * 2);
3707         inode_inc_iversion(inode);
3708         inode_inc_iversion(dir);
3709         inode->i_ctime = dir->i_mtime = dir->i_ctime = CURRENT_TIME;
3710         ret = btrfs_update_inode(trans, root, dir);
3711 out:
3712         return ret;
3713 }
3714
3715 int btrfs_unlink_inode(struct btrfs_trans_handle *trans,
3716                        struct btrfs_root *root,
3717                        struct inode *dir, struct inode *inode,
3718                        const char *name, int name_len)
3719 {
3720         int ret;
3721         ret = __btrfs_unlink_inode(trans, root, dir, inode, name, name_len);
3722         if (!ret) {
3723                 drop_nlink(inode);
3724                 ret = btrfs_update_inode(trans, root, inode);
3725         }
3726         return ret;
3727 }
3728
3729 /*
3730  * helper to start transaction for unlink and rmdir.
3731  *
3732  * unlink and rmdir are special in btrfs, they do not always free space, so
3733  * if we cannot make our reservations the normal way try and see if there is
3734  * plenty of slack room in the global reserve to migrate, otherwise we cannot
3735  * allow the unlink to occur.
3736  */
3737 static struct btrfs_trans_handle *__unlink_start_trans(struct inode *dir)
3738 {
3739         struct btrfs_trans_handle *trans;
3740         struct btrfs_root *root = BTRFS_I(dir)->root;
3741         int ret;
3742
3743         /*
3744          * 1 for the possible orphan item
3745          * 1 for the dir item
3746          * 1 for the dir index
3747          * 1 for the inode ref
3748          * 1 for the inode
3749          */
3750         trans = btrfs_start_transaction(root, 5);
3751         if (!IS_ERR(trans) || PTR_ERR(trans) != -ENOSPC)
3752                 return trans;
3753
3754         if (PTR_ERR(trans) == -ENOSPC) {
3755                 u64 num_bytes = btrfs_calc_trans_metadata_size(root, 5);
3756
3757                 trans = btrfs_start_transaction(root, 0);
3758                 if (IS_ERR(trans))
3759                         return trans;
3760                 ret = btrfs_cond_migrate_bytes(root->fs_info,
3761                                                &root->fs_info->trans_block_rsv,
3762                                                num_bytes, 5);
3763                 if (ret) {
3764                         btrfs_end_transaction(trans, root);
3765                         return ERR_PTR(ret);
3766                 }
3767                 trans->block_rsv = &root->fs_info->trans_block_rsv;
3768                 trans->bytes_reserved = num_bytes;
3769         }
3770         return trans;
3771 }
3772
3773 static int btrfs_unlink(struct inode *dir, struct dentry *dentry)
3774 {
3775         struct btrfs_root *root = BTRFS_I(dir)->root;
3776         struct btrfs_trans_handle *trans;
3777         struct inode *inode = dentry->d_inode;
3778         int ret;
3779
3780         trans = __unlink_start_trans(dir);
3781         if (IS_ERR(trans))
3782                 return PTR_ERR(trans);
3783
3784         btrfs_record_unlink_dir(trans, dir, dentry->d_inode, 0);
3785
3786         ret = btrfs_unlink_inode(trans, root, dir, dentry->d_inode,
3787                                  dentry->d_name.name, dentry->d_name.len);
3788         if (ret)
3789                 goto out;
3790
3791         if (inode->i_nlink == 0) {
3792                 ret = btrfs_orphan_add(trans, inode);
3793                 if (ret)
3794                         goto out;
3795         }
3796
3797 out:
3798         btrfs_end_transaction(trans, root);
3799         btrfs_btree_balance_dirty(root);
3800         return ret;
3801 }
3802
3803 int btrfs_unlink_subvol(struct btrfs_trans_handle *trans,
3804                         struct btrfs_root *root,
3805                         struct inode *dir, u64 objectid,
3806                         const char *name, int name_len)
3807 {
3808         struct btrfs_path *path;
3809         struct extent_buffer *leaf;
3810         struct btrfs_dir_item *di;
3811         struct btrfs_key key;
3812         u64 index;
3813         int ret;
3814         u64 dir_ino = btrfs_ino(dir);
3815
3816         path = btrfs_alloc_path();
3817         if (!path)
3818                 return -ENOMEM;
3819
3820         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
3821                                    name, name_len, -1);
3822         if (IS_ERR_OR_NULL(di)) {
3823                 if (!di)
3824                         ret = -ENOENT;
3825                 else
3826                         ret = PTR_ERR(di);
3827                 goto out;
3828         }
3829
3830         leaf = path->nodes[0];
3831         btrfs_dir_item_key_to_cpu(leaf, di, &key);
3832         WARN_ON(key.type != BTRFS_ROOT_ITEM_KEY || key.objectid != objectid);
3833         ret = btrfs_delete_one_dir_name(trans, root, path, di);
3834         if (ret) {
3835                 btrfs_abort_transaction(trans, root, ret);
3836                 goto out;
3837         }
3838         btrfs_release_path(path);
3839
3840         ret = btrfs_del_root_ref(trans, root->fs_info->tree_root,
3841                                  objectid, root->root_key.objectid,
3842                                  dir_ino, &index, name, name_len);
3843         if (ret < 0) {
3844                 if (ret != -ENOENT) {
3845                         btrfs_abort_transaction(trans, root, ret);
3846                         goto out;
3847                 }
3848                 di = btrfs_search_dir_index_item(root, path, dir_ino,
3849                                                  name, name_len);
3850                 if (IS_ERR_OR_NULL(di)) {
3851                         if (!di)
3852                                 ret = -ENOENT;
3853                         else
3854                                 ret = PTR_ERR(di);
3855                         btrfs_abort_transaction(trans, root, ret);
3856                         goto out;
3857                 }
3858
3859                 leaf = path->nodes[0];
3860                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3861                 btrfs_release_path(path);
3862                 index = key.offset;
3863         }
3864         btrfs_release_path(path);
3865
3866         ret = btrfs_delete_delayed_dir_index(trans, root, dir, index);
3867         if (ret) {
3868                 btrfs_abort_transaction(trans, root, ret);
3869                 goto out;
3870         }
3871
3872         btrfs_i_size_write(dir, dir->i_size - name_len * 2);
3873         inode_inc_iversion(dir);
3874         dir->i_mtime = dir->i_ctime = CURRENT_TIME;
3875         ret = btrfs_update_inode_fallback(trans, root, dir);
3876         if (ret)
3877                 btrfs_abort_transaction(trans, root, ret);
3878 out:
3879         btrfs_free_path(path);
3880         return ret;
3881 }
3882
3883 static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
3884 {
3885         struct inode *inode = dentry->d_inode;
3886         int err = 0;
3887         struct btrfs_root *root = BTRFS_I(dir)->root;
3888         struct btrfs_trans_handle *trans;
3889
3890         if (inode->i_size > BTRFS_EMPTY_DIR_SIZE)
3891                 return -ENOTEMPTY;
3892         if (btrfs_ino(inode) == BTRFS_FIRST_FREE_OBJECTID)
3893                 return -EPERM;
3894
3895         trans = __unlink_start_trans(dir);
3896         if (IS_ERR(trans))
3897                 return PTR_ERR(trans);
3898
3899         if (unlikely(btrfs_ino(inode) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
3900                 err = btrfs_unlink_subvol(trans, root, dir,
3901                                           BTRFS_I(inode)->location.objectid,
3902                                           dentry->d_name.name,
3903                                           dentry->d_name.len);
3904                 goto out;
3905         }
3906
3907         err = btrfs_orphan_add(trans, inode);
3908         if (err)
3909                 goto out;
3910
3911         /* now the directory is empty */
3912         err = btrfs_unlink_inode(trans, root, dir, dentry->d_inode,
3913                                  dentry->d_name.name, dentry->d_name.len);
3914         if (!err)
3915                 btrfs_i_size_write(inode, 0);
3916 out:
3917         btrfs_end_transaction(trans, root);
3918         btrfs_btree_balance_dirty(root);
3919
3920         return err;
3921 }
3922
3923 /*
3924  * this can truncate away extent items, csum items and directory items.
3925  * It starts at a high offset and removes keys until it can't find
3926  * any higher than new_size
3927  *
3928  * csum items that cross the new i_size are truncated to the new size
3929  * as well.
3930  *
3931  * min_type is the minimum key type to truncate down to.  If set to 0, this
3932  * will kill all the items on this inode, including the INODE_ITEM_KEY.
3933  */
3934 int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
3935                                struct btrfs_root *root,
3936                                struct inode *inode,
3937                                u64 new_size, u32 min_type)
3938 {
3939         struct btrfs_path *path;
3940         struct extent_buffer *leaf;
3941         struct btrfs_file_extent_item *fi;
3942         struct btrfs_key key;
3943         struct btrfs_key found_key;
3944         u64 extent_start = 0;
3945         u64 extent_num_bytes = 0;
3946         u64 extent_offset = 0;
3947         u64 item_end = 0;
3948         u64 last_size = (u64)-1;
3949         u32 found_type = (u8)-1;
3950         int found_extent;
3951         int del_item;
3952         int pending_del_nr = 0;
3953         int pending_del_slot = 0;
3954         int extent_type = -1;
3955         int ret;
3956         int err = 0;
3957         u64 ino = btrfs_ino(inode);
3958
3959         BUG_ON(new_size > 0 && min_type != BTRFS_EXTENT_DATA_KEY);
3960
3961         path = btrfs_alloc_path();
3962         if (!path)
3963                 return -ENOMEM;
3964         path->reada = -1;
3965
3966         /*
3967          * We want to drop from the next block forward in case this new size is
3968          * not block aligned since we will be keeping the last block of the
3969          * extent just the way it is.
3970          */
3971         if (root->ref_cows || root == root->fs_info->tree_root)
3972                 btrfs_drop_extent_cache(inode, ALIGN(new_size,
3973                                         root->sectorsize), (u64)-1, 0);
3974
3975         /*
3976          * This function is also used to drop the items in the log tree before
3977          * we relog the inode, so if root != BTRFS_I(inode)->root, it means
3978          * it is used to drop the loged items. So we shouldn't kill the delayed
3979          * items.
3980          */
3981         if (min_type == 0 && root == BTRFS_I(inode)->root)
3982                 btrfs_kill_delayed_inode_items(inode);
3983
3984         key.objectid = ino;
3985         key.offset = (u64)-1;
3986         key.type = (u8)-1;
3987
3988 search_again:
3989         path->leave_spinning = 1;
3990         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
3991         if (ret < 0) {
3992                 err = ret;
3993                 goto out;
3994         }
3995
3996         if (ret > 0) {
3997                 /* there are no items in the tree for us to truncate, we're
3998                  * done
3999                  */
4000                 if (path->slots[0] == 0)
4001                         goto out;
4002                 path->slots[0]--;
4003         }
4004
4005         while (1) {
4006                 fi = NULL;
4007                 leaf = path->nodes[0];
4008                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
4009                 found_type = btrfs_key_type(&found_key);
4010
4011                 if (found_key.objectid != ino)
4012                         break;
4013
4014                 if (found_type < min_type)
4015                         break;
4016
4017                 item_end = found_key.offset;
4018                 if (found_type == BTRFS_EXTENT_DATA_KEY) {
4019                         fi = btrfs_item_ptr(leaf, path->slots[0],
4020                                             struct btrfs_file_extent_item);
4021                         extent_type = btrfs_file_extent_type(leaf, fi);
4022                         if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
4023                                 item_end +=
4024                                     btrfs_file_extent_num_bytes(leaf, fi);
4025                         } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
4026                                 item_end += btrfs_file_extent_inline_len(leaf,
4027                                                          path->slots[0], fi);
4028                         }
4029                         item_end--;
4030                 }
4031                 if (found_type > min_type) {
4032                         del_item = 1;
4033                 } else {
4034                         if (item_end < new_size)
4035                                 break;
4036                         if (found_key.offset >= new_size)
4037                                 del_item = 1;
4038                         else
4039                                 del_item = 0;
4040                 }
4041                 found_extent = 0;
4042                 /* FIXME, shrink the extent if the ref count is only 1 */
4043                 if (found_type != BTRFS_EXTENT_DATA_KEY)
4044                         goto delete;
4045
4046                 if (del_item)
4047                         last_size = found_key.offset;
4048                 else
4049                         last_size = new_size;
4050
4051                 if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
4052                         u64 num_dec;
4053                         extent_start = btrfs_file_extent_disk_bytenr(leaf, fi);
4054                         if (!del_item) {
4055                                 u64 orig_num_bytes =
4056                                         btrfs_file_extent_num_bytes(leaf, fi);
4057                                 extent_num_bytes = ALIGN(new_size -
4058                                                 found_key.offset,
4059                                                 root->sectorsize);
4060                                 btrfs_set_file_extent_num_bytes(leaf, fi,
4061                                                          extent_num_bytes);
4062                                 num_dec = (orig_num_bytes -
4063                                            extent_num_bytes);
4064                                 if (root->ref_cows && extent_start != 0)
4065                                         inode_sub_bytes(inode, num_dec);
4066                                 btrfs_mark_buffer_dirty(leaf);
4067                         } else {
4068                                 extent_num_bytes =
4069                                         btrfs_file_extent_disk_num_bytes(leaf,
4070                                                                          fi);
4071                                 extent_offset = found_key.offset -
4072                                         btrfs_file_extent_offset(leaf, fi);
4073
4074                                 /* FIXME blocksize != 4096 */
4075                                 num_dec = btrfs_file_extent_num_bytes(leaf, fi);
4076                                 if (extent_start != 0) {
4077                                         found_extent = 1;
4078                                         if (root->ref_cows)
4079                                                 inode_sub_bytes(inode, num_dec);
4080                                 }
4081                         }
4082                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
4083                         /*
4084                          * we can't truncate inline items that have had
4085                          * special encodings
4086                          */
4087                         if (!del_item &&
4088                             btrfs_file_extent_compression(leaf, fi) == 0 &&
4089                             btrfs_file_extent_encryption(leaf, fi) == 0 &&
4090                             btrfs_file_extent_other_encoding(leaf, fi) == 0) {
4091                                 u32 size = new_size - found_key.offset;
4092
4093                                 if (root->ref_cows) {
4094                                         inode_sub_bytes(inode, item_end + 1 -
4095                                                         new_size);
4096                                 }
4097
4098                                 /*
4099                                  * update the ram bytes to properly reflect
4100                                  * the new size of our item
4101                                  */
4102                                 btrfs_set_file_extent_ram_bytes(leaf, fi, size);
4103                                 size =
4104                                     btrfs_file_extent_calc_inline_size(size);
4105                                 btrfs_truncate_item(root, path, size, 1);
4106                         } else if (root->ref_cows) {
4107                                 inode_sub_bytes(inode, item_end + 1 -
4108                                                 found_key.offset);
4109                         }
4110                 }
4111 delete:
4112                 if (del_item) {
4113                         if (!pending_del_nr) {
4114                                 /* no pending yet, add ourselves */
4115                                 pending_del_slot = path->slots[0];
4116                                 pending_del_nr = 1;
4117                         } else if (pending_del_nr &&
4118                                    path->slots[0] + 1 == pending_del_slot) {
4119                                 /* hop on the pending chunk */
4120                                 pending_del_nr++;
4121                                 pending_del_slot = path->slots[0];
4122                         } else {
4123                                 BUG();
4124                         }
4125                 } else {
4126                         break;
4127                 }
4128                 if (found_extent && (root->ref_cows ||
4129                                      root == root->fs_info->tree_root)) {
4130                         btrfs_set_path_blocking(path);
4131                         ret = btrfs_free_extent(trans, root, extent_start,
4132                                                 extent_num_bytes, 0,
4133                                                 btrfs_header_owner(leaf),
4134                                                 ino, extent_offset, 0);
4135                         BUG_ON(ret);
4136                 }
4137
4138                 if (found_type == BTRFS_INODE_ITEM_KEY)
4139                         break;
4140
4141                 if (path->slots[0] == 0 ||
4142                     path->slots[0] != pending_del_slot) {
4143                         if (pending_del_nr) {
4144                                 ret = btrfs_del_items(trans, root, path,
4145                                                 pending_del_slot,
4146                                                 pending_del_nr);
4147                                 if (ret) {
4148                                         btrfs_abort_transaction(trans,
4149                                                                 root, ret);
4150                                         goto error;
4151                                 }
4152                                 pending_del_nr = 0;
4153                         }
4154                         btrfs_release_path(path);
4155                         goto search_again;
4156                 } else {
4157                         path->slots[0]--;
4158                 }
4159         }
4160 out:
4161         if (pending_del_nr) {
4162                 ret = btrfs_del_items(trans, root, path, pending_del_slot,
4163                                       pending_del_nr);
4164                 if (ret)
4165                         btrfs_abort_transaction(trans, root, ret);
4166         }
4167 error:
4168         if (last_size != (u64)-1)
4169                 btrfs_ordered_update_i_size(inode, last_size, NULL);
4170         btrfs_free_path(path);
4171         return err;
4172 }
4173
4174 /*
4175  * btrfs_truncate_page - read, zero a chunk and write a page
4176  * @inode - inode that we're zeroing
4177  * @from - the offset to start zeroing
4178  * @len - the length to zero, 0 to zero the entire range respective to the
4179  *      offset
4180  * @front - zero up to the offset instead of from the offset on
4181  *
4182  * This will find the page for the "from" offset and cow the page and zero the
4183  * part we want to zero.  This is used with truncate and hole punching.
4184  */
4185 int btrfs_truncate_page(struct inode *inode, loff_t from, loff_t len,
4186                         int front)
4187 {
4188         struct address_space *mapping = inode->i_mapping;
4189         struct btrfs_root *root = BTRFS_I(inode)->root;
4190         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4191         struct btrfs_ordered_extent *ordered;
4192         struct extent_state *cached_state = NULL;
4193         char *kaddr;
4194         u32 blocksize = root->sectorsize;
4195         pgoff_t index = from >> PAGE_CACHE_SHIFT;
4196         unsigned offset = from & (PAGE_CACHE_SIZE-1);
4197         struct page *page;
4198         gfp_t mask = btrfs_alloc_write_mask(mapping);
4199         int ret = 0;
4200         u64 page_start;
4201         u64 page_end;
4202
4203         if ((offset & (blocksize - 1)) == 0 &&
4204             (!len || ((len & (blocksize - 1)) == 0)))
4205                 goto out;
4206         ret = btrfs_delalloc_reserve_space(inode, PAGE_CACHE_SIZE);
4207         if (ret)
4208                 goto out;
4209
4210 again:
4211         page = find_or_create_page(mapping, index, mask);
4212         if (!page) {
4213                 btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
4214                 ret = -ENOMEM;
4215                 goto out;
4216         }
4217
4218         page_start = page_offset(page);
4219         page_end = page_start + PAGE_CACHE_SIZE - 1;
4220
4221         if (!PageUptodate(page)) {
4222                 ret = btrfs_readpage(NULL, page);
4223                 lock_page(page);
4224                 if (page->mapping != mapping) {
4225                         unlock_page(page);
4226                         page_cache_release(page);
4227                         goto again;
4228                 }
4229                 if (!PageUptodate(page)) {
4230                         ret = -EIO;
4231                         goto out_unlock;
4232                 }
4233         }
4234         wait_on_page_writeback(page);
4235
4236         lock_extent_bits(io_tree, page_start, page_end, 0, &cached_state);
4237         set_page_extent_mapped(page);
4238
4239         ordered = btrfs_lookup_ordered_extent(inode, page_start);
4240         if (ordered) {
4241                 unlock_extent_cached(io_tree, page_start, page_end,
4242                                      &cached_state, GFP_NOFS);
4243                 unlock_page(page);
4244                 page_cache_release(page);
4245                 btrfs_start_ordered_extent(inode, ordered, 1);
4246                 btrfs_put_ordered_extent(ordered);
4247                 goto again;
4248         }
4249
4250         clear_extent_bit(&BTRFS_I(inode)->io_tree, page_start, page_end,
4251                           EXTENT_DIRTY | EXTENT_DELALLOC |
4252                           EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
4253                           0, 0, &cached_state, GFP_NOFS);
4254
4255         ret = btrfs_set_extent_delalloc(inode, page_start, page_end,
4256                                         &cached_state);
4257         if (ret) {
4258                 unlock_extent_cached(io_tree, page_start, page_end,
4259                                      &cached_state, GFP_NOFS);
4260                 goto out_unlock;
4261         }
4262
4263         if (offset != PAGE_CACHE_SIZE) {
4264                 if (!len)
4265                         len = PAGE_CACHE_SIZE - offset;
4266                 kaddr = kmap(page);
4267                 if (front)
4268                         memset(kaddr, 0, offset);
4269                 else
4270                         memset(kaddr + offset, 0, len);
4271                 flush_dcache_page(page);
4272                 kunmap(page);
4273         }
4274         ClearPageChecked(page);
4275         set_page_dirty(page);
4276         unlock_extent_cached(io_tree, page_start, page_end, &cached_state,
4277                              GFP_NOFS);
4278
4279 out_unlock:
4280         if (ret)
4281                 btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
4282         unlock_page(page);
4283         page_cache_release(page);
4284 out:
4285         return ret;
4286 }
4287
4288 static int maybe_insert_hole(struct btrfs_root *root, struct inode *inode,
4289                              u64 offset, u64 len)
4290 {
4291         struct btrfs_trans_handle *trans;
4292         int ret;
4293
4294         /*
4295          * Still need to make sure the inode looks like it's been updated so
4296          * that any holes get logged if we fsync.
4297          */
4298         if (btrfs_fs_incompat(root->fs_info, NO_HOLES)) {
4299                 BTRFS_I(inode)->last_trans = root->fs_info->generation;
4300                 BTRFS_I(inode)->last_sub_trans = root->log_transid;
4301                 BTRFS_I(inode)->last_log_commit = root->last_log_commit;
4302                 return 0;
4303         }
4304
4305         /*
4306          * 1 - for the one we're dropping
4307          * 1 - for the one we're adding
4308          * 1 - for updating the inode.
4309          */
4310         trans = btrfs_start_transaction(root, 3);
4311         if (IS_ERR(trans))
4312                 return PTR_ERR(trans);
4313
4314         ret = btrfs_drop_extents(trans, root, inode, offset, offset + len, 1);
4315         if (ret) {
4316                 btrfs_abort_transaction(trans, root, ret);
4317                 btrfs_end_transaction(trans, root);
4318                 return ret;
4319         }
4320
4321         ret = btrfs_insert_file_extent(trans, root, btrfs_ino(inode), offset,
4322                                        0, 0, len, 0, len, 0, 0, 0);
4323         if (ret)
4324                 btrfs_abort_transaction(trans, root, ret);
4325         else
4326                 btrfs_update_inode(trans, root, inode);
4327         btrfs_end_transaction(trans, root);
4328         return ret;
4329 }
4330
4331 /*
4332  * This function puts in dummy file extents for the area we're creating a hole
4333  * for.  So if we are truncating this file to a larger size we need to insert
4334  * these file extents so that btrfs_get_extent will return a EXTENT_MAP_HOLE for
4335  * the range between oldsize and size
4336  */
4337 int btrfs_cont_expand(struct inode *inode, loff_t oldsize, loff_t size)
4338 {
4339         struct btrfs_root *root = BTRFS_I(inode)->root;
4340         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4341         struct extent_map *em = NULL;
4342         struct extent_state *cached_state = NULL;
4343         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
4344         u64 hole_start = ALIGN(oldsize, root->sectorsize);
4345         u64 block_end = ALIGN(size, root->sectorsize);
4346         u64 last_byte;
4347         u64 cur_offset;
4348         u64 hole_size;
4349         int err = 0;
4350
4351         /*
4352          * If our size started in the middle of a page we need to zero out the
4353          * rest of the page before we expand the i_size, otherwise we could
4354          * expose stale data.
4355          */
4356         err = btrfs_truncate_page(inode, oldsize, 0, 0);
4357         if (err)
4358                 return err;
4359
4360         if (size <= hole_start)
4361                 return 0;
4362
4363         while (1) {
4364                 struct btrfs_ordered_extent *ordered;
4365
4366                 lock_extent_bits(io_tree, hole_start, block_end - 1, 0,
4367                                  &cached_state);
4368                 ordered = btrfs_lookup_ordered_range(inode, hole_start,
4369                                                      block_end - hole_start);
4370                 if (!ordered)
4371                         break;
4372                 unlock_extent_cached(io_tree, hole_start, block_end - 1,
4373                                      &cached_state, GFP_NOFS);
4374                 btrfs_start_ordered_extent(inode, ordered, 1);
4375                 btrfs_put_ordered_extent(ordered);
4376         }
4377
4378         cur_offset = hole_start;
4379         while (1) {
4380                 em = btrfs_get_extent(inode, NULL, 0, cur_offset,
4381                                 block_end - cur_offset, 0);
4382                 if (IS_ERR(em)) {
4383                         err = PTR_ERR(em);
4384                         em = NULL;
4385                         break;
4386                 }
4387                 last_byte = min(extent_map_end(em), block_end);
4388                 last_byte = ALIGN(last_byte , root->sectorsize);
4389                 if (!test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) {
4390                         struct extent_map *hole_em;
4391                         hole_size = last_byte - cur_offset;
4392
4393                         err = maybe_insert_hole(root, inode, cur_offset,
4394                                                 hole_size);
4395                         if (err)
4396                                 break;
4397                         btrfs_drop_extent_cache(inode, cur_offset,
4398                                                 cur_offset + hole_size - 1, 0);
4399                         hole_em = alloc_extent_map();
4400                         if (!hole_em) {
4401                                 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
4402                                         &BTRFS_I(inode)->runtime_flags);
4403                                 goto next;
4404                         }
4405                         hole_em->start = cur_offset;
4406                         hole_em->len = hole_size;
4407                         hole_em->orig_start = cur_offset;
4408
4409                         hole_em->block_start = EXTENT_MAP_HOLE;
4410                         hole_em->block_len = 0;
4411                         hole_em->orig_block_len = 0;
4412                         hole_em->ram_bytes = hole_size;
4413                         hole_em->bdev = root->fs_info->fs_devices->latest_bdev;
4414                         hole_em->compress_type = BTRFS_COMPRESS_NONE;
4415                         hole_em->generation = root->fs_info->generation;
4416
4417                         while (1) {
4418                                 write_lock(&em_tree->lock);
4419                                 err = add_extent_mapping(em_tree, hole_em, 1);
4420                                 write_unlock(&em_tree->lock);
4421                                 if (err != -EEXIST)
4422                                         break;
4423                                 btrfs_drop_extent_cache(inode, cur_offset,
4424                                                         cur_offset +
4425                                                         hole_size - 1, 0);
4426                         }
4427                         free_extent_map(hole_em);
4428                 }
4429 next:
4430                 free_extent_map(em);
4431                 em = NULL;
4432                 cur_offset = last_byte;
4433                 if (cur_offset >= block_end)
4434                         break;
4435         }
4436         free_extent_map(em);
4437         unlock_extent_cached(io_tree, hole_start, block_end - 1, &cached_state,
4438                              GFP_NOFS);
4439         return err;
4440 }
4441
4442 static int btrfs_setsize(struct inode *inode, struct iattr *attr)
4443 {
4444         struct btrfs_root *root = BTRFS_I(inode)->root;
4445         struct btrfs_trans_handle *trans;
4446         loff_t oldsize = i_size_read(inode);
4447         loff_t newsize = attr->ia_size;
4448         int mask = attr->ia_valid;
4449         int ret;
4450
4451         /*
4452          * The regular truncate() case without ATTR_CTIME and ATTR_MTIME is a
4453          * special case where we need to update the times despite not having
4454          * these flags set.  For all other operations the VFS set these flags
4455          * explicitly if it wants a timestamp update.
4456          */
4457         if (newsize != oldsize) {
4458                 inode_inc_iversion(inode);
4459                 if (!(mask & (ATTR_CTIME | ATTR_MTIME)))
4460                         inode->i_ctime = inode->i_mtime =
4461                                 current_fs_time(inode->i_sb);
4462         }
4463
4464         if (newsize > oldsize) {
4465                 truncate_pagecache(inode, newsize);
4466                 ret = btrfs_cont_expand(inode, oldsize, newsize);
4467                 if (ret)
4468                         return ret;
4469
4470                 trans = btrfs_start_transaction(root, 1);
4471                 if (IS_ERR(trans))
4472                         return PTR_ERR(trans);
4473
4474                 i_size_write(inode, newsize);
4475                 btrfs_ordered_update_i_size(inode, i_size_read(inode), NULL);
4476                 ret = btrfs_update_inode(trans, root, inode);
4477                 btrfs_end_transaction(trans, root);
4478         } else {
4479
4480                 /*
4481                  * We're truncating a file that used to have good data down to
4482                  * zero. Make sure it gets into the ordered flush list so that
4483                  * any new writes get down to disk quickly.
4484                  */
4485                 if (newsize == 0)
4486                         set_bit(BTRFS_INODE_ORDERED_DATA_CLOSE,
4487                                 &BTRFS_I(inode)->runtime_flags);
4488
4489                 /*
4490                  * 1 for the orphan item we're going to add
4491                  * 1 for the orphan item deletion.
4492                  */
4493                 trans = btrfs_start_transaction(root, 2);
4494                 if (IS_ERR(trans))
4495                         return PTR_ERR(trans);
4496
4497                 /*
4498                  * We need to do this in case we fail at _any_ point during the
4499                  * actual truncate.  Once we do the truncate_setsize we could
4500                  * invalidate pages which forces any outstanding ordered io to
4501                  * be instantly completed which will give us extents that need
4502                  * to be truncated.  If we fail to get an orphan inode down we
4503                  * could have left over extents that were never meant to live,
4504                  * so we need to garuntee from this point on that everything
4505                  * will be consistent.
4506                  */
4507                 ret = btrfs_orphan_add(trans, inode);
4508                 btrfs_end_transaction(trans, root);
4509                 if (ret)
4510                         return ret;
4511
4512                 /* we don't support swapfiles, so vmtruncate shouldn't fail */
4513                 truncate_setsize(inode, newsize);
4514
4515                 /* Disable nonlocked read DIO to avoid the end less truncate */
4516                 btrfs_inode_block_unlocked_dio(inode);
4517                 inode_dio_wait(inode);
4518                 btrfs_inode_resume_unlocked_dio(inode);
4519
4520                 ret = btrfs_truncate(inode);
4521                 if (ret && inode->i_nlink) {
4522                         int err;
4523
4524                         /*
4525                          * failed to truncate, disk_i_size is only adjusted down
4526                          * as we remove extents, so it should represent the true
4527                          * size of the inode, so reset the in memory size and
4528                          * delete our orphan entry.
4529                          */
4530                         trans = btrfs_join_transaction(root);
4531                         if (IS_ERR(trans)) {
4532                                 btrfs_orphan_del(NULL, inode);
4533                                 return ret;
4534                         }
4535                         i_size_write(inode, BTRFS_I(inode)->disk_i_size);
4536                         err = btrfs_orphan_del(trans, inode);
4537                         if (err)
4538                                 btrfs_abort_transaction(trans, root, err);
4539                         btrfs_end_transaction(trans, root);
4540                 }
4541         }
4542
4543         return ret;
4544 }
4545
4546 static int btrfs_setattr(struct dentry *dentry, struct iattr *attr)
4547 {
4548         struct inode *inode = dentry->d_inode;
4549         struct btrfs_root *root = BTRFS_I(inode)->root;
4550         int err;
4551
4552         if (btrfs_root_readonly(root))
4553                 return -EROFS;
4554
4555         err = inode_change_ok(inode, attr);
4556         if (err)
4557                 return err;
4558
4559         if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) {
4560                 err = btrfs_setsize(inode, attr);
4561                 if (err)
4562                         return err;
4563         }
4564
4565         if (attr->ia_valid) {
4566                 setattr_copy(inode, attr);
4567                 inode_inc_iversion(inode);
4568                 err = btrfs_dirty_inode(inode);
4569
4570                 if (!err && attr->ia_valid & ATTR_MODE)
4571                         err = posix_acl_chmod(inode, inode->i_mode);
4572         }
4573
4574         return err;
4575 }
4576
4577 /*
4578  * While truncating the inode pages during eviction, we get the VFS calling
4579  * btrfs_invalidatepage() against each page of the inode. This is slow because
4580  * the calls to btrfs_invalidatepage() result in a huge amount of calls to
4581  * lock_extent_bits() and clear_extent_bit(), which keep merging and splitting
4582  * extent_state structures over and over, wasting lots of time.
4583  *
4584  * Therefore if the inode is being evicted, let btrfs_invalidatepage() skip all
4585  * those expensive operations on a per page basis and do only the ordered io
4586  * finishing, while we release here the extent_map and extent_state structures,
4587  * without the excessive merging and splitting.
4588  */
4589 static void evict_inode_truncate_pages(struct inode *inode)
4590 {
4591         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4592         struct extent_map_tree *map_tree = &BTRFS_I(inode)->extent_tree;
4593         struct rb_node *node;
4594
4595         ASSERT(inode->i_state & I_FREEING);
4596         truncate_inode_pages(&inode->i_data, 0);
4597
4598         write_lock(&map_tree->lock);
4599         while (!RB_EMPTY_ROOT(&map_tree->map)) {
4600                 struct extent_map *em;
4601
4602                 node = rb_first(&map_tree->map);
4603                 em = rb_entry(node, struct extent_map, rb_node);
4604                 clear_bit(EXTENT_FLAG_PINNED, &em->flags);
4605                 clear_bit(EXTENT_FLAG_LOGGING, &em->flags);
4606                 remove_extent_mapping(map_tree, em);
4607                 free_extent_map(em);
4608         }
4609         write_unlock(&map_tree->lock);
4610
4611         spin_lock(&io_tree->lock);
4612         while (!RB_EMPTY_ROOT(&io_tree->state)) {
4613                 struct extent_state *state;
4614                 struct extent_state *cached_state = NULL;
4615
4616                 node = rb_first(&io_tree->state);
4617                 state = rb_entry(node, struct extent_state, rb_node);
4618                 atomic_inc(&state->refs);
4619                 spin_unlock(&io_tree->lock);
4620
4621                 lock_extent_bits(io_tree, state->start, state->end,
4622                                  0, &cached_state);
4623                 clear_extent_bit(io_tree, state->start, state->end,
4624                                  EXTENT_LOCKED | EXTENT_DIRTY |
4625                                  EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING |
4626                                  EXTENT_DEFRAG, 1, 1,
4627                                  &cached_state, GFP_NOFS);
4628                 free_extent_state(state);
4629
4630                 spin_lock(&io_tree->lock);
4631         }
4632         spin_unlock(&io_tree->lock);
4633 }
4634
4635 void btrfs_evict_inode(struct inode *inode)
4636 {
4637         struct btrfs_trans_handle *trans;
4638         struct btrfs_root *root = BTRFS_I(inode)->root;
4639         struct btrfs_block_rsv *rsv, *global_rsv;
4640         u64 min_size = btrfs_calc_trunc_metadata_size(root, 1);
4641         int ret;
4642
4643         trace_btrfs_inode_evict(inode);
4644
4645         evict_inode_truncate_pages(inode);
4646
4647         if (inode->i_nlink &&
4648             ((btrfs_root_refs(&root->root_item) != 0 &&
4649               root->root_key.objectid != BTRFS_ROOT_TREE_OBJECTID) ||
4650              btrfs_is_free_space_inode(inode)))
4651                 goto no_delete;
4652
4653         if (is_bad_inode(inode)) {
4654                 btrfs_orphan_del(NULL, inode);
4655                 goto no_delete;
4656         }
4657         /* do we really want it for ->i_nlink > 0 and zero btrfs_root_refs? */
4658         btrfs_wait_ordered_range(inode, 0, (u64)-1);
4659
4660         if (root->fs_info->log_root_recovering) {
4661                 BUG_ON(test_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
4662                                  &BTRFS_I(inode)->runtime_flags));
4663                 goto no_delete;
4664         }
4665
4666         if (inode->i_nlink > 0) {
4667                 BUG_ON(btrfs_root_refs(&root->root_item) != 0 &&
4668                        root->root_key.objectid != BTRFS_ROOT_TREE_OBJECTID);
4669                 goto no_delete;
4670         }
4671
4672         ret = btrfs_commit_inode_delayed_inode(inode);
4673         if (ret) {
4674                 btrfs_orphan_del(NULL, inode);
4675                 goto no_delete;
4676         }
4677
4678         rsv = btrfs_alloc_block_rsv(root, BTRFS_BLOCK_RSV_TEMP);
4679         if (!rsv) {
4680                 btrfs_orphan_del(NULL, inode);
4681                 goto no_delete;
4682         }
4683         rsv->size = min_size;
4684         rsv->failfast = 1;
4685         global_rsv = &root->fs_info->global_block_rsv;
4686
4687         btrfs_i_size_write(inode, 0);
4688
4689         /*
4690          * This is a bit simpler than btrfs_truncate since we've already
4691          * reserved our space for our orphan item in the unlink, so we just
4692          * need to reserve some slack space in case we add bytes and update
4693          * inode item when doing the truncate.
4694          */
4695         while (1) {
4696                 ret = btrfs_block_rsv_refill(root, rsv, min_size,
4697                                              BTRFS_RESERVE_FLUSH_LIMIT);
4698
4699                 /*
4700                  * Try and steal from the global reserve since we will
4701                  * likely not use this space anyway, we want to try as
4702                  * hard as possible to get this to work.
4703                  */
4704                 if (ret)
4705                         ret = btrfs_block_rsv_migrate(global_rsv, rsv, min_size);
4706
4707                 if (ret) {
4708                         btrfs_warn(root->fs_info,
4709                                 "Could not get space for a delete, will truncate on mount %d",
4710                                 ret);
4711                         btrfs_orphan_del(NULL, inode);
4712                         btrfs_free_block_rsv(root, rsv);
4713                         goto no_delete;
4714                 }
4715
4716                 trans = btrfs_join_transaction(root);
4717                 if (IS_ERR(trans)) {
4718                         btrfs_orphan_del(NULL, inode);
4719                         btrfs_free_block_rsv(root, rsv);
4720                         goto no_delete;
4721                 }
4722
4723                 trans->block_rsv = rsv;
4724
4725                 ret = btrfs_truncate_inode_items(trans, root, inode, 0, 0);
4726                 if (ret != -ENOSPC)
4727                         break;
4728
4729                 trans->block_rsv = &root->fs_info->trans_block_rsv;
4730                 btrfs_end_transaction(trans, root);
4731                 trans = NULL;
4732                 btrfs_btree_balance_dirty(root);
4733         }
4734
4735         btrfs_free_block_rsv(root, rsv);
4736
4737         /*
4738          * Errors here aren't a big deal, it just means we leave orphan items
4739          * in the tree.  They will be cleaned up on the next mount.
4740          */
4741         if (ret == 0) {
4742                 trans->block_rsv = root->orphan_block_rsv;
4743                 btrfs_orphan_del(trans, inode);
4744         } else {
4745                 btrfs_orphan_del(NULL, inode);
4746         }
4747
4748         trans->block_rsv = &root->fs_info->trans_block_rsv;
4749         if (!(root == root->fs_info->tree_root ||
4750               root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID))
4751                 btrfs_return_ino(root, btrfs_ino(inode));
4752
4753         btrfs_end_transaction(trans, root);
4754         btrfs_btree_balance_dirty(root);
4755 no_delete:
4756         btrfs_remove_delayed_node(inode);
4757         clear_inode(inode);
4758         return;
4759 }
4760
4761 /*
4762  * this returns the key found in the dir entry in the location pointer.
4763  * If no dir entries were found, location->objectid is 0.
4764  */
4765 static int btrfs_inode_by_name(struct inode *dir, struct dentry *dentry,
4766                                struct btrfs_key *location)
4767 {
4768         const char *name = dentry->d_name.name;
4769         int namelen = dentry->d_name.len;
4770         struct btrfs_dir_item *di;
4771         struct btrfs_path *path;
4772         struct btrfs_root *root = BTRFS_I(dir)->root;
4773         int ret = 0;
4774
4775         path = btrfs_alloc_path();
4776         if (!path)
4777                 return -ENOMEM;
4778
4779         di = btrfs_lookup_dir_item(NULL, root, path, btrfs_ino(dir), name,
4780                                     namelen, 0);
4781         if (IS_ERR(di))
4782                 ret = PTR_ERR(di);
4783
4784         if (IS_ERR_OR_NULL(di))
4785                 goto out_err;
4786
4787         btrfs_dir_item_key_to_cpu(path->nodes[0], di, location);
4788 out:
4789         btrfs_free_path(path);
4790         return ret;
4791 out_err:
4792         location->objectid = 0;
4793         goto out;
4794 }
4795
4796 /*
4797  * when we hit a tree root in a directory, the btrfs part of the inode
4798  * needs to be changed to reflect the root directory of the tree root.  This
4799  * is kind of like crossing a mount point.
4800  */
4801 static int fixup_tree_root_location(struct btrfs_root *root,
4802                                     struct inode *dir,
4803                                     struct dentry *dentry,
4804                                     struct btrfs_key *location,
4805                                     struct btrfs_root **sub_root)
4806 {
4807         struct btrfs_path *path;
4808         struct btrfs_root *new_root;
4809         struct btrfs_root_ref *ref;
4810         struct extent_buffer *leaf;
4811         int ret;
4812         int err = 0;
4813
4814         path = btrfs_alloc_path();
4815         if (!path) {
4816                 err = -ENOMEM;
4817                 goto out;
4818         }
4819
4820         err = -ENOENT;
4821         ret = btrfs_find_item(root->fs_info->tree_root, path,
4822                                 BTRFS_I(dir)->root->root_key.objectid,
4823                                 location->objectid, BTRFS_ROOT_REF_KEY, NULL);
4824         if (ret) {
4825                 if (ret < 0)
4826                         err = ret;
4827                 goto out;
4828         }
4829
4830         leaf = path->nodes[0];
4831         ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
4832         if (btrfs_root_ref_dirid(leaf, ref) != btrfs_ino(dir) ||
4833             btrfs_root_ref_name_len(leaf, ref) != dentry->d_name.len)
4834                 goto out;
4835
4836         ret = memcmp_extent_buffer(leaf, dentry->d_name.name,
4837                                    (unsigned long)(ref + 1),
4838                                    dentry->d_name.len);
4839         if (ret)
4840                 goto out;
4841
4842         btrfs_release_path(path);
4843
4844         new_root = btrfs_read_fs_root_no_name(root->fs_info, location);
4845         if (IS_ERR(new_root)) {
4846                 err = PTR_ERR(new_root);
4847                 goto out;
4848         }
4849
4850         *sub_root = new_root;
4851         location->objectid = btrfs_root_dirid(&new_root->root_item);
4852         location->type = BTRFS_INODE_ITEM_KEY;
4853         location->offset = 0;
4854         err = 0;
4855 out:
4856         btrfs_free_path(path);
4857         return err;
4858 }
4859
4860 static void inode_tree_add(struct inode *inode)
4861 {
4862         struct btrfs_root *root = BTRFS_I(inode)->root;
4863         struct btrfs_inode *entry;
4864         struct rb_node **p;
4865         struct rb_node *parent;
4866         struct rb_node *new = &BTRFS_I(inode)->rb_node;
4867         u64 ino = btrfs_ino(inode);
4868
4869         if (inode_unhashed(inode))
4870                 return;
4871         parent = NULL;
4872         spin_lock(&root->inode_lock);
4873         p = &root->inode_tree.rb_node;
4874         while (*p) {
4875                 parent = *p;
4876                 entry = rb_entry(parent, struct btrfs_inode, rb_node);
4877
4878                 if (ino < btrfs_ino(&entry->vfs_inode))
4879                         p = &parent->rb_left;
4880                 else if (ino > btrfs_ino(&entry->vfs_inode))
4881                         p = &parent->rb_right;
4882                 else {
4883                         WARN_ON(!(entry->vfs_inode.i_state &
4884                                   (I_WILL_FREE | I_FREEING)));
4885                         rb_replace_node(parent, new, &root->inode_tree);
4886                         RB_CLEAR_NODE(parent);
4887                         spin_unlock(&root->inode_lock);
4888                         return;
4889                 }
4890         }
4891         rb_link_node(new, parent, p);
4892         rb_insert_color(new, &root->inode_tree);
4893         spin_unlock(&root->inode_lock);
4894 }
4895
4896 static void inode_tree_del(struct inode *inode)
4897 {
4898         struct btrfs_root *root = BTRFS_I(inode)->root;
4899         int empty = 0;
4900
4901         spin_lock(&root->inode_lock);
4902         if (!RB_EMPTY_NODE(&BTRFS_I(inode)->rb_node)) {
4903                 rb_erase(&BTRFS_I(inode)->rb_node, &root->inode_tree);
4904                 RB_CLEAR_NODE(&BTRFS_I(inode)->rb_node);
4905                 empty = RB_EMPTY_ROOT(&root->inode_tree);
4906         }
4907         spin_unlock(&root->inode_lock);
4908
4909         if (empty && btrfs_root_refs(&root->root_item) == 0) {
4910                 synchronize_srcu(&root->fs_info->subvol_srcu);
4911                 spin_lock(&root->inode_lock);
4912                 empty = RB_EMPTY_ROOT(&root->inode_tree);
4913                 spin_unlock(&root->inode_lock);
4914                 if (empty)
4915                         btrfs_add_dead_root(root);
4916         }
4917 }
4918
4919 void btrfs_invalidate_inodes(struct btrfs_root *root)
4920 {
4921         struct rb_node *node;
4922         struct rb_node *prev;
4923         struct btrfs_inode *entry;
4924         struct inode *inode;
4925         u64 objectid = 0;
4926
4927         WARN_ON(btrfs_root_refs(&root->root_item) != 0);
4928
4929         spin_lock(&root->inode_lock);
4930 again:
4931         node = root->inode_tree.rb_node;
4932         prev = NULL;
4933         while (node) {
4934                 prev = node;
4935                 entry = rb_entry(node, struct btrfs_inode, rb_node);
4936
4937                 if (objectid < btrfs_ino(&entry->vfs_inode))
4938                         node = node->rb_left;
4939                 else if (objectid > btrfs_ino(&entry->vfs_inode))
4940                         node = node->rb_right;
4941                 else
4942                         break;
4943         }
4944         if (!node) {
4945                 while (prev) {
4946                         entry = rb_entry(prev, struct btrfs_inode, rb_node);
4947                         if (objectid <= btrfs_ino(&entry->vfs_inode)) {
4948                                 node = prev;
4949                                 break;
4950                         }
4951                         prev = rb_next(prev);
4952                 }
4953         }
4954         while (node) {
4955                 entry = rb_entry(node, struct btrfs_inode, rb_node);
4956                 objectid = btrfs_ino(&entry->vfs_inode) + 1;
4957                 inode = igrab(&entry->vfs_inode);
4958                 if (inode) {
4959                         spin_unlock(&root->inode_lock);
4960                         if (atomic_read(&inode->i_count) > 1)
4961                                 d_prune_aliases(inode);
4962                         /*
4963                          * btrfs_drop_inode will have it removed from
4964                          * the inode cache when its usage count
4965                          * hits zero.
4966                          */
4967                         iput(inode);
4968                         cond_resched();
4969                         spin_lock(&root->inode_lock);
4970                         goto again;
4971                 }
4972
4973                 if (cond_resched_lock(&root->inode_lock))
4974                         goto again;
4975
4976                 node = rb_next(node);
4977         }
4978         spin_unlock(&root->inode_lock);
4979 }
4980
4981 static int btrfs_init_locked_inode(struct inode *inode, void *p)
4982 {
4983         struct btrfs_iget_args *args = p;
4984         inode->i_ino = args->location->objectid;
4985         memcpy(&BTRFS_I(inode)->location, args->location,
4986                sizeof(*args->location));
4987         BTRFS_I(inode)->root = args->root;
4988         return 0;
4989 }
4990
4991 static int btrfs_find_actor(struct inode *inode, void *opaque)
4992 {
4993         struct btrfs_iget_args *args = opaque;
4994         return args->location->objectid == BTRFS_I(inode)->location.objectid &&
4995                 args->root == BTRFS_I(inode)->root;
4996 }
4997
4998 static struct inode *btrfs_iget_locked(struct super_block *s,
4999                                        struct btrfs_key *location,
5000                                        struct btrfs_root *root)
5001 {
5002         struct inode *inode;
5003         struct btrfs_iget_args args;
5004         unsigned long hashval = btrfs_inode_hash(location->objectid, root);
5005
5006         args.location = location;
5007         args.root = root;
5008
5009         inode = iget5_locked(s, hashval, btrfs_find_actor,
5010                              btrfs_init_locked_inode,
5011                              (void *)&args);
5012         return inode;
5013 }
5014
5015 /* Get an inode object given its location and corresponding root.
5016  * Returns in *is_new if the inode was read from disk
5017  */
5018 struct inode *btrfs_iget(struct super_block *s, struct btrfs_key *location,
5019                          struct btrfs_root *root, int *new)
5020 {
5021         struct inode *inode;
5022
5023         inode = btrfs_iget_locked(s, location, root);
5024         if (!inode)
5025                 return ERR_PTR(-ENOMEM);
5026
5027         if (inode->i_state & I_NEW) {
5028                 btrfs_read_locked_inode(inode);
5029                 if (!is_bad_inode(inode)) {
5030                         inode_tree_add(inode);
5031                         unlock_new_inode(inode);
5032                         if (new)
5033                                 *new = 1;
5034                 } else {
5035                         unlock_new_inode(inode);
5036                         iput(inode);
5037                         inode = ERR_PTR(-ESTALE);
5038                 }
5039         }
5040
5041         return inode;
5042 }
5043
5044 static struct inode *new_simple_dir(struct super_block *s,
5045                                     struct btrfs_key *key,
5046                                     struct btrfs_root *root)
5047 {
5048         struct inode *inode = new_inode(s);
5049
5050         if (!inode)
5051                 return ERR_PTR(-ENOMEM);
5052
5053         BTRFS_I(inode)->root = root;
5054         memcpy(&BTRFS_I(inode)->location, key, sizeof(*key));
5055         set_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags);
5056
5057         inode->i_ino = BTRFS_EMPTY_SUBVOL_DIR_OBJECTID;
5058         inode->i_op = &btrfs_dir_ro_inode_operations;
5059         inode->i_fop = &simple_dir_operations;
5060         inode->i_mode = S_IFDIR | S_IRUGO | S_IWUSR | S_IXUGO;
5061         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
5062
5063         return inode;
5064 }
5065
5066 struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry)
5067 {
5068         struct inode *inode;
5069         struct btrfs_root *root = BTRFS_I(dir)->root;
5070         struct btrfs_root *sub_root = root;
5071         struct btrfs_key location;
5072         int index;
5073         int ret = 0;
5074
5075         if (dentry->d_name.len > BTRFS_NAME_LEN)
5076                 return ERR_PTR(-ENAMETOOLONG);
5077
5078         ret = btrfs_inode_by_name(dir, dentry, &location);
5079         if (ret < 0)
5080                 return ERR_PTR(ret);
5081
5082         if (location.objectid == 0)
5083                 return ERR_PTR(-ENOENT);
5084
5085         if (location.type == BTRFS_INODE_ITEM_KEY) {
5086                 inode = btrfs_iget(dir->i_sb, &location, root, NULL);
5087                 return inode;
5088         }
5089
5090         BUG_ON(location.type != BTRFS_ROOT_ITEM_KEY);
5091
5092         index = srcu_read_lock(&root->fs_info->subvol_srcu);
5093         ret = fixup_tree_root_location(root, dir, dentry,
5094                                        &location, &sub_root);
5095         if (ret < 0) {
5096                 if (ret != -ENOENT)
5097                         inode = ERR_PTR(ret);
5098                 else
5099                         inode = new_simple_dir(dir->i_sb, &location, sub_root);
5100         } else {
5101                 inode = btrfs_iget(dir->i_sb, &location, sub_root, NULL);
5102         }
5103         srcu_read_unlock(&root->fs_info->subvol_srcu, index);
5104
5105         if (!IS_ERR(inode) && root != sub_root) {
5106                 down_read(&root->fs_info->cleanup_work_sem);
5107                 if (!(inode->i_sb->s_flags & MS_RDONLY))
5108                         ret = btrfs_orphan_cleanup(sub_root);
5109                 up_read(&root->fs_info->cleanup_work_sem);
5110                 if (ret) {
5111                         iput(inode);
5112                         inode = ERR_PTR(ret);
5113                 }
5114         }
5115
5116         return inode;
5117 }
5118
5119 static int btrfs_dentry_delete(const struct dentry *dentry)
5120 {
5121         struct btrfs_root *root;
5122         struct inode *inode = dentry->d_inode;
5123
5124         if (!inode && !IS_ROOT(dentry))
5125                 inode = dentry->d_parent->d_inode;
5126
5127         if (inode) {
5128                 root = BTRFS_I(inode)->root;
5129                 if (btrfs_root_refs(&root->root_item) == 0)
5130                         return 1;
5131
5132                 if (btrfs_ino(inode) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
5133                         return 1;
5134         }
5135         return 0;
5136 }
5137
5138 static void btrfs_dentry_release(struct dentry *dentry)
5139 {
5140         if (dentry->d_fsdata)
5141                 kfree(dentry->d_fsdata);
5142 }
5143
5144 static struct dentry *btrfs_lookup(struct inode *dir, struct dentry *dentry,
5145                                    unsigned int flags)
5146 {
5147         struct inode *inode;
5148
5149         inode = btrfs_lookup_dentry(dir, dentry);
5150         if (IS_ERR(inode)) {
5151                 if (PTR_ERR(inode) == -ENOENT)
5152                         inode = NULL;
5153                 else
5154                         return ERR_CAST(inode);
5155         }
5156
5157         return d_splice_alias(inode, dentry);
5158 }
5159
5160 unsigned char btrfs_filetype_table[] = {
5161         DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
5162 };
5163
5164 static int btrfs_real_readdir(struct file *file, struct dir_context *ctx)
5165 {
5166         struct inode *inode = file_inode(file);
5167         struct btrfs_root *root = BTRFS_I(inode)->root;
5168         struct btrfs_item *item;
5169         struct btrfs_dir_item *di;
5170         struct btrfs_key key;
5171         struct btrfs_key found_key;
5172         struct btrfs_path *path;
5173         struct list_head ins_list;
5174         struct list_head del_list;
5175         int ret;
5176         struct extent_buffer *leaf;
5177         int slot;
5178         unsigned char d_type;
5179         int over = 0;
5180         u32 di_cur;
5181         u32 di_total;
5182         u32 di_len;
5183         int key_type = BTRFS_DIR_INDEX_KEY;
5184         char tmp_name[32];
5185         char *name_ptr;
5186         int name_len;
5187         int is_curr = 0;        /* ctx->pos points to the current index? */
5188
5189         /* FIXME, use a real flag for deciding about the key type */
5190         if (root->fs_info->tree_root == root)
5191                 key_type = BTRFS_DIR_ITEM_KEY;
5192
5193         if (!dir_emit_dots(file, ctx))
5194                 return 0;
5195
5196         path = btrfs_alloc_path();
5197         if (!path)
5198                 return -ENOMEM;
5199
5200         path->reada = 1;
5201
5202         if (key_type == BTRFS_DIR_INDEX_KEY) {
5203                 INIT_LIST_HEAD(&ins_list);
5204                 INIT_LIST_HEAD(&del_list);
5205                 btrfs_get_delayed_items(inode, &ins_list, &del_list);
5206         }
5207
5208         btrfs_set_key_type(&key, key_type);
5209         key.offset = ctx->pos;
5210         key.objectid = btrfs_ino(inode);
5211
5212         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
5213         if (ret < 0)
5214                 goto err;
5215
5216         while (1) {
5217                 leaf = path->nodes[0];
5218                 slot = path->slots[0];
5219                 if (slot >= btrfs_header_nritems(leaf)) {
5220                         ret = btrfs_next_leaf(root, path);
5221                         if (ret < 0)
5222                                 goto err;
5223                         else if (ret > 0)
5224                                 break;
5225                         continue;
5226                 }
5227
5228                 item = btrfs_item_nr(slot);
5229                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
5230
5231                 if (found_key.objectid != key.objectid)
5232                         break;
5233                 if (btrfs_key_type(&found_key) != key_type)
5234                         break;
5235                 if (found_key.offset < ctx->pos)
5236                         goto next;
5237                 if (key_type == BTRFS_DIR_INDEX_KEY &&
5238                     btrfs_should_delete_dir_index(&del_list,
5239                                                   found_key.offset))
5240                         goto next;
5241
5242                 ctx->pos = found_key.offset;
5243                 is_curr = 1;
5244
5245                 di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
5246                 di_cur = 0;
5247                 di_total = btrfs_item_size(leaf, item);
5248
5249                 while (di_cur < di_total) {
5250                         struct btrfs_key location;
5251
5252                         if (verify_dir_item(root, leaf, di))
5253                                 break;
5254
5255                         name_len = btrfs_dir_name_len(leaf, di);
5256                         if (name_len <= sizeof(tmp_name)) {
5257                                 name_ptr = tmp_name;
5258                         } else {
5259                                 name_ptr = kmalloc(name_len, GFP_NOFS);
5260                                 if (!name_ptr) {
5261                                         ret = -ENOMEM;
5262                                         goto err;
5263                                 }
5264                         }
5265                         read_extent_buffer(leaf, name_ptr,
5266                                            (unsigned long)(di + 1), name_len);
5267
5268                         d_type = btrfs_filetype_table[btrfs_dir_type(leaf, di)];
5269                         btrfs_dir_item_key_to_cpu(leaf, di, &location);
5270
5271
5272                         /* is this a reference to our own snapshot? If so
5273                          * skip it.
5274                          *
5275                          * In contrast to old kernels, we insert the snapshot's
5276                          * dir item and dir index after it has been created, so
5277                          * we won't find a reference to our own snapshot. We
5278                          * still keep the following code for backward
5279                          * compatibility.
5280                          */
5281                         if (location.type == BTRFS_ROOT_ITEM_KEY &&
5282                             location.objectid == root->root_key.objectid) {
5283                                 over = 0;
5284                                 goto skip;
5285                         }
5286                         over = !dir_emit(ctx, name_ptr, name_len,
5287                                        location.objectid, d_type);
5288
5289 skip:
5290                         if (name_ptr != tmp_name)
5291                                 kfree(name_ptr);
5292
5293                         if (over)
5294                                 goto nopos;
5295                         di_len = btrfs_dir_name_len(leaf, di) +
5296                                  btrfs_dir_data_len(leaf, di) + sizeof(*di);
5297                         di_cur += di_len;
5298                         di = (struct btrfs_dir_item *)((char *)di + di_len);
5299                 }
5300 next:
5301                 path->slots[0]++;
5302         }
5303
5304         if (key_type == BTRFS_DIR_INDEX_KEY) {
5305                 if (is_curr)
5306                         ctx->pos++;
5307                 ret = btrfs_readdir_delayed_dir_index(ctx, &ins_list);
5308                 if (ret)
5309                         goto nopos;
5310         }
5311
5312         /* Reached end of directory/root. Bump pos past the last item. */
5313         ctx->pos++;
5314
5315         /*
5316          * Stop new entries from being returned after we return the last
5317          * entry.
5318          *
5319          * New directory entries are assigned a strictly increasing
5320          * offset.  This means that new entries created during readdir
5321          * are *guaranteed* to be seen in the future by that readdir.
5322          * This has broken buggy programs which operate on names as
5323          * they're returned by readdir.  Until we re-use freed offsets
5324          * we have this hack to stop new entries from being returned
5325          * under the assumption that they'll never reach this huge
5326          * offset.
5327          *
5328          * This is being careful not to overflow 32bit loff_t unless the
5329          * last entry requires it because doing so has broken 32bit apps
5330          * in the past.
5331          */
5332         if (key_type == BTRFS_DIR_INDEX_KEY) {
5333                 if (ctx->pos >= INT_MAX)
5334                         ctx->pos = LLONG_MAX;
5335                 else
5336                         ctx->pos = INT_MAX;
5337         }
5338 nopos:
5339         ret = 0;
5340 err:
5341         if (key_type == BTRFS_DIR_INDEX_KEY)
5342                 btrfs_put_delayed_items(&ins_list, &del_list);
5343         btrfs_free_path(path);
5344         return ret;
5345 }
5346
5347 int btrfs_write_inode(struct inode *inode, struct writeback_control *wbc)
5348 {
5349         struct btrfs_root *root = BTRFS_I(inode)->root;
5350         struct btrfs_trans_handle *trans;
5351         int ret = 0;
5352         bool nolock = false;
5353
5354         if (test_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags))
5355                 return 0;
5356
5357         if (btrfs_fs_closing(root->fs_info) && btrfs_is_free_space_inode(inode))
5358                 nolock = true;
5359
5360         if (wbc->sync_mode == WB_SYNC_ALL) {
5361                 if (nolock)
5362                         trans = btrfs_join_transaction_nolock(root);
5363                 else
5364                         trans = btrfs_join_transaction(root);
5365                 if (IS_ERR(trans))
5366                         return PTR_ERR(trans);
5367                 ret = btrfs_commit_transaction(trans, root);
5368         }
5369         return ret;
5370 }
5371
5372 /*
5373  * This is somewhat expensive, updating the tree every time the
5374  * inode changes.  But, it is most likely to find the inode in cache.
5375  * FIXME, needs more benchmarking...there are no reasons other than performance
5376  * to keep or drop this code.
5377  */
5378 static int btrfs_dirty_inode(struct inode *inode)
5379 {
5380         struct btrfs_root *root = BTRFS_I(inode)->root;
5381         struct btrfs_trans_handle *trans;
5382         int ret;
5383
5384         if (test_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags))
5385                 return 0;
5386
5387         trans = btrfs_join_transaction(root);
5388         if (IS_ERR(trans))
5389                 return PTR_ERR(trans);
5390
5391         ret = btrfs_update_inode(trans, root, inode);
5392         if (ret && ret == -ENOSPC) {
5393                 /* whoops, lets try again with the full transaction */
5394                 btrfs_end_transaction(trans, root);
5395                 trans = btrfs_start_transaction(root, 1);
5396                 if (IS_ERR(trans))
5397                         return PTR_ERR(trans);
5398
5399                 ret = btrfs_update_inode(trans, root, inode);
5400         }
5401         btrfs_end_transaction(trans, root);
5402         if (BTRFS_I(inode)->delayed_node)
5403                 btrfs_balance_delayed_items(root);
5404
5405         return ret;
5406 }
5407
5408 /*
5409  * This is a copy of file_update_time.  We need this so we can return error on
5410  * ENOSPC for updating the inode in the case of file write and mmap writes.
5411  */
5412 static int btrfs_update_time(struct inode *inode, struct timespec *now,
5413                              int flags)
5414 {
5415         struct btrfs_root *root = BTRFS_I(inode)->root;
5416
5417         if (btrfs_root_readonly(root))
5418                 return -EROFS;
5419
5420         if (flags & S_VERSION)
5421                 inode_inc_iversion(inode);
5422         if (flags & S_CTIME)
5423                 inode->i_ctime = *now;
5424         if (flags & S_MTIME)
5425                 inode->i_mtime = *now;
5426         if (flags & S_ATIME)
5427                 inode->i_atime = *now;
5428         return btrfs_dirty_inode(inode);
5429 }
5430
5431 /*
5432  * find the highest existing sequence number in a directory
5433  * and then set the in-memory index_cnt variable to reflect
5434  * free sequence numbers
5435  */
5436 static int btrfs_set_inode_index_count(struct inode *inode)
5437 {
5438         struct btrfs_root *root = BTRFS_I(inode)->root;
5439         struct btrfs_key key, found_key;
5440         struct btrfs_path *path;
5441         struct extent_buffer *leaf;
5442         int ret;
5443
5444         key.objectid = btrfs_ino(inode);
5445         btrfs_set_key_type(&key, BTRFS_DIR_INDEX_KEY);
5446         key.offset = (u64)-1;
5447
5448         path = btrfs_alloc_path();
5449         if (!path)
5450                 return -ENOMEM;
5451
5452         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
5453         if (ret < 0)
5454                 goto out;
5455         /* FIXME: we should be able to handle this */
5456         if (ret == 0)
5457                 goto out;
5458         ret = 0;
5459
5460         /*
5461          * MAGIC NUMBER EXPLANATION:
5462          * since we search a directory based on f_pos we have to start at 2
5463          * since '.' and '..' have f_pos of 0 and 1 respectively, so everybody
5464          * else has to start at 2
5465          */
5466         if (path->slots[0] == 0) {
5467                 BTRFS_I(inode)->index_cnt = 2;
5468                 goto out;
5469         }
5470
5471         path->slots[0]--;
5472
5473         leaf = path->nodes[0];
5474         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
5475
5476         if (found_key.objectid != btrfs_ino(inode) ||
5477             btrfs_key_type(&found_key) != BTRFS_DIR_INDEX_KEY) {
5478                 BTRFS_I(inode)->index_cnt = 2;
5479                 goto out;
5480         }
5481
5482         BTRFS_I(inode)->index_cnt = found_key.offset + 1;
5483 out:
5484         btrfs_free_path(path);
5485         return ret;
5486 }
5487
5488 /*
5489  * helper to find a free sequence number in a given directory.  This current
5490  * code is very simple, later versions will do smarter things in the btree
5491  */
5492 int btrfs_set_inode_index(struct inode *dir, u64 *index)
5493 {
5494         int ret = 0;
5495
5496         if (BTRFS_I(dir)->index_cnt == (u64)-1) {
5497                 ret = btrfs_inode_delayed_dir_index_count(dir);
5498                 if (ret) {
5499                         ret = btrfs_set_inode_index_count(dir);
5500                         if (ret)
5501                                 return ret;
5502                 }
5503         }
5504
5505         *index = BTRFS_I(dir)->index_cnt;
5506         BTRFS_I(dir)->index_cnt++;
5507
5508         return ret;
5509 }
5510
5511 static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
5512                                      struct btrfs_root *root,
5513                                      struct inode *dir,
5514                                      const char *name, int name_len,
5515                                      u64 ref_objectid, u64 objectid,
5516                                      umode_t mode, u64 *index)
5517 {
5518         struct inode *inode;
5519         struct btrfs_inode_item *inode_item;
5520         struct btrfs_key *location;
5521         struct btrfs_path *path;
5522         struct btrfs_inode_ref *ref;
5523         struct btrfs_key key[2];
5524         u32 sizes[2];
5525         unsigned long ptr;
5526         int ret;
5527
5528         path = btrfs_alloc_path();
5529         if (!path)
5530                 return ERR_PTR(-ENOMEM);
5531
5532         inode = new_inode(root->fs_info->sb);
5533         if (!inode) {
5534                 btrfs_free_path(path);
5535                 return ERR_PTR(-ENOMEM);
5536         }
5537
5538         /*
5539          * we have to initialize this early, so we can reclaim the inode
5540          * number if we fail afterwards in this function.
5541          */
5542         inode->i_ino = objectid;
5543
5544         if (dir) {
5545                 trace_btrfs_inode_request(dir);
5546
5547                 ret = btrfs_set_inode_index(dir, index);
5548                 if (ret) {
5549                         btrfs_free_path(path);
5550                         iput(inode);
5551                         return ERR_PTR(ret);
5552                 }
5553         }
5554         /*
5555          * index_cnt is ignored for everything but a dir,
5556          * btrfs_get_inode_index_count has an explanation for the magic
5557          * number
5558          */
5559         BTRFS_I(inode)->index_cnt = 2;
5560         BTRFS_I(inode)->dir_index = *index;
5561         BTRFS_I(inode)->root = root;
5562         BTRFS_I(inode)->generation = trans->transid;
5563         inode->i_generation = BTRFS_I(inode)->generation;
5564
5565         /*
5566          * We could have gotten an inode number from somebody who was fsynced
5567          * and then removed in this same transaction, so let's just set full
5568          * sync since it will be a full sync anyway and this will blow away the
5569          * old info in the log.
5570          */
5571         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
5572
5573         key[0].objectid = objectid;
5574         btrfs_set_key_type(&key[0], BTRFS_INODE_ITEM_KEY);
5575         key[0].offset = 0;
5576
5577         /*
5578          * Start new inodes with an inode_ref. This is slightly more
5579          * efficient for small numbers of hard links since they will
5580          * be packed into one item. Extended refs will kick in if we
5581          * add more hard links than can fit in the ref item.
5582          */
5583         key[1].objectid = objectid;
5584         btrfs_set_key_type(&key[1], BTRFS_INODE_REF_KEY);
5585         key[1].offset = ref_objectid;
5586
5587         sizes[0] = sizeof(struct btrfs_inode_item);
5588         sizes[1] = name_len + sizeof(*ref);
5589
5590         path->leave_spinning = 1;
5591         ret = btrfs_insert_empty_items(trans, root, path, key, sizes, 2);
5592         if (ret != 0)
5593                 goto fail;
5594
5595         inode_init_owner(inode, dir, mode);
5596         inode_set_bytes(inode, 0);
5597         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
5598         inode_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
5599                                   struct btrfs_inode_item);
5600         memset_extent_buffer(path->nodes[0], 0, (unsigned long)inode_item,
5601                              sizeof(*inode_item));
5602         fill_inode_item(trans, path->nodes[0], inode_item, inode);
5603
5604         ref = btrfs_item_ptr(path->nodes[0], path->slots[0] + 1,
5605                              struct btrfs_inode_ref);
5606         btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
5607         btrfs_set_inode_ref_index(path->nodes[0], ref, *index);
5608         ptr = (unsigned long)(ref + 1);
5609         write_extent_buffer(path->nodes[0], name, ptr, name_len);
5610
5611         btrfs_mark_buffer_dirty(path->nodes[0]);
5612         btrfs_free_path(path);
5613
5614         location = &BTRFS_I(inode)->location;
5615         location->objectid = objectid;
5616         location->offset = 0;
5617         btrfs_set_key_type(location, BTRFS_INODE_ITEM_KEY);
5618
5619         btrfs_inherit_iflags(inode, dir);
5620
5621         if (S_ISREG(mode)) {
5622                 if (btrfs_test_opt(root, NODATASUM))
5623                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM;
5624                 if (btrfs_test_opt(root, NODATACOW))
5625                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATACOW |
5626                                 BTRFS_INODE_NODATASUM;
5627         }
5628
5629         btrfs_insert_inode_hash(inode);
5630         inode_tree_add(inode);
5631
5632         trace_btrfs_inode_new(inode);
5633         btrfs_set_inode_last_trans(trans, inode);
5634
5635         btrfs_update_root_times(trans, root);
5636
5637         ret = btrfs_inode_inherit_props(trans, inode, dir);
5638         if (ret)
5639                 btrfs_err(root->fs_info,
5640                           "error inheriting props for ino %llu (root %llu): %d",
5641                           btrfs_ino(inode), root->root_key.objectid, ret);
5642
5643         return inode;
5644 fail:
5645         if (dir)
5646                 BTRFS_I(dir)->index_cnt--;
5647         btrfs_free_path(path);
5648         iput(inode);
5649         return ERR_PTR(ret);
5650 }
5651
5652 static inline u8 btrfs_inode_type(struct inode *inode)
5653 {
5654         return btrfs_type_by_mode[(inode->i_mode & S_IFMT) >> S_SHIFT];
5655 }
5656
5657 /*
5658  * utility function to add 'inode' into 'parent_inode' with
5659  * a give name and a given sequence number.
5660  * if 'add_backref' is true, also insert a backref from the
5661  * inode to the parent directory.
5662  */
5663 int btrfs_add_link(struct btrfs_trans_handle *trans,
5664                    struct inode *parent_inode, struct inode *inode,
5665                    const char *name, int name_len, int add_backref, u64 index)
5666 {
5667         int ret = 0;
5668         struct btrfs_key key;
5669         struct btrfs_root *root = BTRFS_I(parent_inode)->root;
5670         u64 ino = btrfs_ino(inode);
5671         u64 parent_ino = btrfs_ino(parent_inode);
5672
5673         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
5674                 memcpy(&key, &BTRFS_I(inode)->root->root_key, sizeof(key));
5675         } else {
5676                 key.objectid = ino;
5677                 btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
5678                 key.offset = 0;
5679         }
5680
5681         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
5682                 ret = btrfs_add_root_ref(trans, root->fs_info->tree_root,
5683                                          key.objectid, root->root_key.objectid,
5684                                          parent_ino, index, name, name_len);
5685         } else if (add_backref) {
5686                 ret = btrfs_insert_inode_ref(trans, root, name, name_len, ino,
5687                                              parent_ino, index);
5688         }
5689
5690         /* Nothing to clean up yet */
5691         if (ret)
5692                 return ret;
5693
5694         ret = btrfs_insert_dir_item(trans, root, name, name_len,
5695                                     parent_inode, &key,
5696                                     btrfs_inode_type(inode), index);
5697         if (ret == -EEXIST || ret == -EOVERFLOW)
5698                 goto fail_dir_item;
5699         else if (ret) {
5700                 btrfs_abort_transaction(trans, root, ret);
5701                 return ret;
5702         }
5703
5704         btrfs_i_size_write(parent_inode, parent_inode->i_size +
5705                            name_len * 2);
5706         inode_inc_iversion(parent_inode);
5707         parent_inode->i_mtime = parent_inode->i_ctime = CURRENT_TIME;
5708         ret = btrfs_update_inode(trans, root, parent_inode);
5709         if (ret)
5710                 btrfs_abort_transaction(trans, root, ret);
5711         return ret;
5712
5713 fail_dir_item:
5714         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
5715                 u64 local_index;
5716                 int err;
5717                 err = btrfs_del_root_ref(trans, root->fs_info->tree_root,
5718                                  key.objectid, root->root_key.objectid,
5719                                  parent_ino, &local_index, name, name_len);
5720
5721         } else if (add_backref) {
5722                 u64 local_index;
5723                 int err;
5724
5725                 err = btrfs_del_inode_ref(trans, root, name, name_len,
5726                                           ino, parent_ino, &local_index);
5727         }
5728         return ret;
5729 }
5730
5731 static int btrfs_add_nondir(struct btrfs_trans_handle *trans,
5732                             struct inode *dir, struct dentry *dentry,
5733                             struct inode *inode, int backref, u64 index)
5734 {
5735         int err = btrfs_add_link(trans, dir, inode,
5736                                  dentry->d_name.name, dentry->d_name.len,
5737                                  backref, index);
5738         if (err > 0)
5739                 err = -EEXIST;
5740         return err;
5741 }
5742
5743 static int btrfs_mknod(struct inode *dir, struct dentry *dentry,
5744                         umode_t mode, dev_t rdev)
5745 {
5746         struct btrfs_trans_handle *trans;
5747         struct btrfs_root *root = BTRFS_I(dir)->root;
5748         struct inode *inode = NULL;
5749         int err;
5750         int drop_inode = 0;
5751         u64 objectid;
5752         u64 index = 0;
5753
5754         if (!new_valid_dev(rdev))
5755                 return -EINVAL;
5756
5757         /*
5758          * 2 for inode item and ref
5759          * 2 for dir items
5760          * 1 for xattr if selinux is on
5761          */
5762         trans = btrfs_start_transaction(root, 5);
5763         if (IS_ERR(trans))
5764                 return PTR_ERR(trans);
5765
5766         err = btrfs_find_free_ino(root, &objectid);
5767         if (err)
5768                 goto out_unlock;
5769
5770         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
5771                                 dentry->d_name.len, btrfs_ino(dir), objectid,
5772                                 mode, &index);
5773         if (IS_ERR(inode)) {
5774                 err = PTR_ERR(inode);
5775                 goto out_unlock;
5776         }
5777
5778         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
5779         if (err) {
5780                 drop_inode = 1;
5781                 goto out_unlock;
5782         }
5783
5784         /*
5785         * If the active LSM wants to access the inode during
5786         * d_instantiate it needs these. Smack checks to see
5787         * if the filesystem supports xattrs by looking at the
5788         * ops vector.
5789         */
5790
5791         inode->i_op = &btrfs_special_inode_operations;
5792         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
5793         if (err)
5794                 drop_inode = 1;
5795         else {
5796                 init_special_inode(inode, inode->i_mode, rdev);
5797                 btrfs_update_inode(trans, root, inode);
5798                 d_instantiate(dentry, inode);
5799         }
5800 out_unlock:
5801         btrfs_end_transaction(trans, root);
5802         btrfs_btree_balance_dirty(root);
5803         if (drop_inode) {
5804                 inode_dec_link_count(inode);
5805                 iput(inode);
5806         }
5807         return err;
5808 }
5809
5810 static int btrfs_create(struct inode *dir, struct dentry *dentry,
5811                         umode_t mode, bool excl)
5812 {
5813         struct btrfs_trans_handle *trans;
5814         struct btrfs_root *root = BTRFS_I(dir)->root;
5815         struct inode *inode = NULL;
5816         int drop_inode_on_err = 0;
5817         int err;
5818         u64 objectid;
5819         u64 index = 0;
5820
5821         /*
5822          * 2 for inode item and ref
5823          * 2 for dir items
5824          * 1 for xattr if selinux is on
5825          */
5826         trans = btrfs_start_transaction(root, 5);
5827         if (IS_ERR(trans))
5828                 return PTR_ERR(trans);
5829
5830         err = btrfs_find_free_ino(root, &objectid);
5831         if (err)
5832                 goto out_unlock;
5833
5834         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
5835                                 dentry->d_name.len, btrfs_ino(dir), objectid,
5836                                 mode, &index);
5837         if (IS_ERR(inode)) {
5838                 err = PTR_ERR(inode);
5839                 goto out_unlock;
5840         }
5841         drop_inode_on_err = 1;
5842
5843         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
5844         if (err)
5845                 goto out_unlock;
5846
5847         err = btrfs_update_inode(trans, root, inode);
5848         if (err)
5849                 goto out_unlock;
5850
5851         /*
5852         * If the active LSM wants to access the inode during
5853         * d_instantiate it needs these. Smack checks to see
5854         * if the filesystem supports xattrs by looking at the
5855         * ops vector.
5856         */
5857         inode->i_fop = &btrfs_file_operations;
5858         inode->i_op = &btrfs_file_inode_operations;
5859
5860         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
5861         if (err)
5862                 goto out_unlock;
5863
5864         inode->i_mapping->a_ops = &btrfs_aops;
5865         inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
5866         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
5867         d_instantiate(dentry, inode);
5868
5869 out_unlock:
5870         btrfs_end_transaction(trans, root);
5871         if (err && drop_inode_on_err) {
5872                 inode_dec_link_count(inode);
5873                 iput(inode);
5874         }
5875         btrfs_btree_balance_dirty(root);
5876         return err;
5877 }
5878
5879 static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
5880                       struct dentry *dentry)
5881 {
5882         struct btrfs_trans_handle *trans;
5883         struct btrfs_root *root = BTRFS_I(dir)->root;
5884         struct inode *inode = old_dentry->d_inode;
5885         u64 index;
5886         int err;
5887         int drop_inode = 0;
5888
5889         /* do not allow sys_link's with other subvols of the same device */
5890         if (root->objectid != BTRFS_I(inode)->root->objectid)
5891                 return -EXDEV;
5892
5893         if (inode->i_nlink >= BTRFS_LINK_MAX)
5894                 return -EMLINK;
5895
5896         err = btrfs_set_inode_index(dir, &index);
5897         if (err)
5898                 goto fail;
5899
5900         /*
5901          * 2 items for inode and inode ref
5902          * 2 items for dir items
5903          * 1 item for parent inode
5904          */
5905         trans = btrfs_start_transaction(root, 5);
5906         if (IS_ERR(trans)) {
5907                 err = PTR_ERR(trans);
5908                 goto fail;
5909         }
5910
5911         /* There are several dir indexes for this inode, clear the cache. */
5912         BTRFS_I(inode)->dir_index = 0ULL;
5913         inc_nlink(inode);
5914         inode_inc_iversion(inode);
5915         inode->i_ctime = CURRENT_TIME;
5916         ihold(inode);
5917         set_bit(BTRFS_INODE_COPY_EVERYTHING, &BTRFS_I(inode)->runtime_flags);
5918
5919         err = btrfs_add_nondir(trans, dir, dentry, inode, 1, index);
5920
5921         if (err) {
5922                 drop_inode = 1;
5923         } else {
5924                 struct dentry *parent = dentry->d_parent;
5925                 err = btrfs_update_inode(trans, root, inode);
5926                 if (err)
5927                         goto fail;
5928                 d_instantiate(dentry, inode);
5929                 btrfs_log_new_name(trans, inode, NULL, parent);
5930         }
5931
5932         btrfs_end_transaction(trans, root);
5933 fail:
5934         if (drop_inode) {
5935                 inode_dec_link_count(inode);
5936                 iput(inode);
5937         }
5938         btrfs_btree_balance_dirty(root);
5939         return err;
5940 }
5941
5942 static int btrfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
5943 {
5944         struct inode *inode = NULL;
5945         struct btrfs_trans_handle *trans;
5946         struct btrfs_root *root = BTRFS_I(dir)->root;
5947         int err = 0;
5948         int drop_on_err = 0;
5949         u64 objectid = 0;
5950         u64 index = 0;
5951
5952         /*
5953          * 2 items for inode and ref
5954          * 2 items for dir items
5955          * 1 for xattr if selinux is on
5956          */
5957         trans = btrfs_start_transaction(root, 5);
5958         if (IS_ERR(trans))
5959                 return PTR_ERR(trans);
5960
5961         err = btrfs_find_free_ino(root, &objectid);
5962         if (err)
5963                 goto out_fail;
5964
5965         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
5966                                 dentry->d_name.len, btrfs_ino(dir), objectid,
5967                                 S_IFDIR | mode, &index);
5968         if (IS_ERR(inode)) {
5969                 err = PTR_ERR(inode);
5970                 goto out_fail;
5971         }
5972
5973         drop_on_err = 1;
5974
5975         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
5976         if (err)
5977                 goto out_fail;
5978
5979         inode->i_op = &btrfs_dir_inode_operations;
5980         inode->i_fop = &btrfs_dir_file_operations;
5981
5982         btrfs_i_size_write(inode, 0);
5983         err = btrfs_update_inode(trans, root, inode);
5984         if (err)
5985                 goto out_fail;
5986
5987         err = btrfs_add_link(trans, dir, inode, dentry->d_name.name,
5988                              dentry->d_name.len, 0, index);
5989         if (err)
5990                 goto out_fail;
5991
5992         d_instantiate(dentry, inode);
5993         drop_on_err = 0;
5994
5995 out_fail:
5996         btrfs_end_transaction(trans, root);
5997         if (drop_on_err)
5998                 iput(inode);
5999         btrfs_btree_balance_dirty(root);
6000         return err;
6001 }
6002
6003 /* helper for btfs_get_extent.  Given an existing extent in the tree,
6004  * and an extent that you want to insert, deal with overlap and insert
6005  * the new extent into the tree.
6006  */
6007 static int merge_extent_mapping(struct extent_map_tree *em_tree,
6008                                 struct extent_map *existing,
6009                                 struct extent_map *em,
6010                                 u64 map_start, u64 map_len)
6011 {
6012         u64 start_diff;
6013
6014         BUG_ON(map_start < em->start || map_start >= extent_map_end(em));
6015         start_diff = map_start - em->start;
6016         em->start = map_start;
6017         em->len = map_len;
6018         if (em->block_start < EXTENT_MAP_LAST_BYTE &&
6019             !test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
6020                 em->block_start += start_diff;
6021                 em->block_len -= start_diff;
6022         }
6023         return add_extent_mapping(em_tree, em, 0);
6024 }
6025
6026 static noinline int uncompress_inline(struct btrfs_path *path,
6027                                       struct inode *inode, struct page *page,
6028                                       size_t pg_offset, u64 extent_offset,
6029                                       struct btrfs_file_extent_item *item)
6030 {
6031         int ret;
6032         struct extent_buffer *leaf = path->nodes[0];
6033         char *tmp;
6034         size_t max_size;
6035         unsigned long inline_size;
6036         unsigned long ptr;
6037         int compress_type;
6038
6039         WARN_ON(pg_offset != 0);
6040         compress_type = btrfs_file_extent_compression(leaf, item);
6041         max_size = btrfs_file_extent_ram_bytes(leaf, item);
6042         inline_size = btrfs_file_extent_inline_item_len(leaf,
6043                                         btrfs_item_nr(path->slots[0]));
6044         tmp = kmalloc(inline_size, GFP_NOFS);
6045         if (!tmp)
6046                 return -ENOMEM;
6047         ptr = btrfs_file_extent_inline_start(item);
6048
6049         read_extent_buffer(leaf, tmp, ptr, inline_size);
6050
6051         max_size = min_t(unsigned long, PAGE_CACHE_SIZE, max_size);
6052         ret = btrfs_decompress(compress_type, tmp, page,
6053                                extent_offset, inline_size, max_size);
6054         if (ret) {
6055                 char *kaddr = kmap_atomic(page);
6056                 unsigned long copy_size = min_t(u64,
6057                                   PAGE_CACHE_SIZE - pg_offset,
6058                                   max_size - extent_offset);
6059                 memset(kaddr + pg_offset, 0, copy_size);
6060                 kunmap_atomic(kaddr);
6061         }
6062         kfree(tmp);
6063         return 0;
6064 }
6065
6066 /*
6067  * a bit scary, this does extent mapping from logical file offset to the disk.
6068  * the ugly parts come from merging extents from the disk with the in-ram
6069  * representation.  This gets more complex because of the data=ordered code,
6070  * where the in-ram extents might be locked pending data=ordered completion.
6071  *
6072  * This also copies inline extents directly into the page.
6073  */
6074
6075 struct extent_map *btrfs_get_extent(struct inode *inode, struct page *page,
6076                                     size_t pg_offset, u64 start, u64 len,
6077                                     int create)
6078 {
6079         int ret;
6080         int err = 0;
6081         u64 bytenr;
6082         u64 extent_start = 0;
6083         u64 extent_end = 0;
6084         u64 objectid = btrfs_ino(inode);
6085         u32 found_type;
6086         struct btrfs_path *path = NULL;
6087         struct btrfs_root *root = BTRFS_I(inode)->root;
6088         struct btrfs_file_extent_item *item;
6089         struct extent_buffer *leaf;
6090         struct btrfs_key found_key;
6091         struct extent_map *em = NULL;
6092         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
6093         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
6094         struct btrfs_trans_handle *trans = NULL;
6095         int compress_type;
6096
6097 again:
6098         read_lock(&em_tree->lock);
6099         em = lookup_extent_mapping(em_tree, start, len);
6100         if (em)
6101                 em->bdev = root->fs_info->fs_devices->latest_bdev;
6102         read_unlock(&em_tree->lock);
6103
6104         if (em) {
6105                 if (em->start > start || em->start + em->len <= start)
6106                         free_extent_map(em);
6107                 else if (em->block_start == EXTENT_MAP_INLINE && page)
6108                         free_extent_map(em);
6109                 else
6110                         goto out;
6111         }
6112         em = alloc_extent_map();
6113         if (!em) {
6114                 err = -ENOMEM;
6115                 goto out;
6116         }
6117         em->bdev = root->fs_info->fs_devices->latest_bdev;
6118         em->start = EXTENT_MAP_HOLE;
6119         em->orig_start = EXTENT_MAP_HOLE;
6120         em->len = (u64)-1;
6121         em->block_len = (u64)-1;
6122
6123         if (!path) {
6124                 path = btrfs_alloc_path();
6125                 if (!path) {
6126                         err = -ENOMEM;
6127                         goto out;
6128                 }
6129                 /*
6130                  * Chances are we'll be called again, so go ahead and do
6131                  * readahead
6132                  */
6133                 path->reada = 1;
6134         }
6135
6136         ret = btrfs_lookup_file_extent(trans, root, path,
6137                                        objectid, start, trans != NULL);
6138         if (ret < 0) {
6139                 err = ret;
6140                 goto out;
6141         }
6142
6143         if (ret != 0) {
6144                 if (path->slots[0] == 0)
6145                         goto not_found;
6146                 path->slots[0]--;
6147         }
6148
6149         leaf = path->nodes[0];
6150         item = btrfs_item_ptr(leaf, path->slots[0],
6151                               struct btrfs_file_extent_item);
6152         /* are we inside the extent that was found? */
6153         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6154         found_type = btrfs_key_type(&found_key);
6155         if (found_key.objectid != objectid ||
6156             found_type != BTRFS_EXTENT_DATA_KEY) {
6157                 /*
6158                  * If we backup past the first extent we want to move forward
6159                  * and see if there is an extent in front of us, otherwise we'll
6160                  * say there is a hole for our whole search range which can
6161                  * cause problems.
6162                  */
6163                 extent_end = start;
6164                 goto next;
6165         }
6166
6167         found_type = btrfs_file_extent_type(leaf, item);
6168         extent_start = found_key.offset;
6169         compress_type = btrfs_file_extent_compression(leaf, item);
6170         if (found_type == BTRFS_FILE_EXTENT_REG ||
6171             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
6172                 extent_end = extent_start +
6173                        btrfs_file_extent_num_bytes(leaf, item);
6174         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
6175                 size_t size;
6176                 size = btrfs_file_extent_inline_len(leaf, path->slots[0], item);
6177                 extent_end = ALIGN(extent_start + size, root->sectorsize);
6178         }
6179 next:
6180         if (start >= extent_end) {
6181                 path->slots[0]++;
6182                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
6183                         ret = btrfs_next_leaf(root, path);
6184                         if (ret < 0) {
6185                                 err = ret;
6186                                 goto out;
6187                         }
6188                         if (ret > 0)
6189                                 goto not_found;
6190                         leaf = path->nodes[0];
6191                 }
6192                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6193                 if (found_key.objectid != objectid ||
6194                     found_key.type != BTRFS_EXTENT_DATA_KEY)
6195                         goto not_found;
6196                 if (start + len <= found_key.offset)
6197                         goto not_found;
6198                 em->start = start;
6199                 em->orig_start = start;
6200                 em->len = found_key.offset - start;
6201                 goto not_found_em;
6202         }
6203
6204         em->ram_bytes = btrfs_file_extent_ram_bytes(leaf, item);
6205         if (found_type == BTRFS_FILE_EXTENT_REG ||
6206             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
6207                 em->start = extent_start;
6208                 em->len = extent_end - extent_start;
6209                 em->orig_start = extent_start -
6210                                  btrfs_file_extent_offset(leaf, item);
6211                 em->orig_block_len = btrfs_file_extent_disk_num_bytes(leaf,
6212                                                                       item);
6213                 bytenr = btrfs_file_extent_disk_bytenr(leaf, item);
6214                 if (bytenr == 0) {
6215                         em->block_start = EXTENT_MAP_HOLE;
6216                         goto insert;
6217                 }
6218                 if (compress_type != BTRFS_COMPRESS_NONE) {
6219                         set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
6220                         em->compress_type = compress_type;
6221                         em->block_start = bytenr;
6222                         em->block_len = em->orig_block_len;
6223                 } else {
6224                         bytenr += btrfs_file_extent_offset(leaf, item);
6225                         em->block_start = bytenr;
6226                         em->block_len = em->len;
6227                         if (found_type == BTRFS_FILE_EXTENT_PREALLOC)
6228                                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
6229                 }
6230                 goto insert;
6231         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
6232                 unsigned long ptr;
6233                 char *map;
6234                 size_t size;
6235                 size_t extent_offset;
6236                 size_t copy_size;
6237
6238                 em->block_start = EXTENT_MAP_INLINE;
6239                 if (!page || create) {
6240                         em->start = extent_start;
6241                         em->len = extent_end - extent_start;
6242                         goto out;
6243                 }
6244
6245                 size = btrfs_file_extent_inline_len(leaf, path->slots[0], item);
6246                 extent_offset = page_offset(page) + pg_offset - extent_start;
6247                 copy_size = min_t(u64, PAGE_CACHE_SIZE - pg_offset,
6248                                 size - extent_offset);
6249                 em->start = extent_start + extent_offset;
6250                 em->len = ALIGN(copy_size, root->sectorsize);
6251                 em->orig_block_len = em->len;
6252                 em->orig_start = em->start;
6253                 if (compress_type) {
6254                         set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
6255                         em->compress_type = compress_type;
6256                 }
6257                 ptr = btrfs_file_extent_inline_start(item) + extent_offset;
6258                 if (create == 0 && !PageUptodate(page)) {
6259                         if (btrfs_file_extent_compression(leaf, item) !=
6260                             BTRFS_COMPRESS_NONE) {
6261                                 ret = uncompress_inline(path, inode, page,
6262                                                         pg_offset,
6263                                                         extent_offset, item);
6264                                 BUG_ON(ret); /* -ENOMEM */
6265                         } else {
6266                                 map = kmap(page);
6267                                 read_extent_buffer(leaf, map + pg_offset, ptr,
6268                                                    copy_size);
6269                                 if (pg_offset + copy_size < PAGE_CACHE_SIZE) {
6270                                         memset(map + pg_offset + copy_size, 0,
6271                                                PAGE_CACHE_SIZE - pg_offset -
6272                                                copy_size);
6273                                 }
6274                                 kunmap(page);
6275                         }
6276                         flush_dcache_page(page);
6277                 } else if (create && PageUptodate(page)) {
6278                         BUG();
6279                         if (!trans) {
6280                                 kunmap(page);
6281                                 free_extent_map(em);
6282                                 em = NULL;
6283
6284                                 btrfs_release_path(path);
6285                                 trans = btrfs_join_transaction(root);
6286
6287                                 if (IS_ERR(trans))
6288                                         return ERR_CAST(trans);
6289                                 goto again;
6290                         }
6291                         map = kmap(page);
6292                         write_extent_buffer(leaf, map + pg_offset, ptr,
6293                                             copy_size);
6294                         kunmap(page);
6295                         btrfs_mark_buffer_dirty(leaf);
6296                 }
6297                 set_extent_uptodate(io_tree, em->start,
6298                                     extent_map_end(em) - 1, NULL, GFP_NOFS);
6299                 goto insert;
6300         } else {
6301                 WARN(1, KERN_ERR "btrfs unknown found_type %d\n", found_type);
6302         }
6303 not_found:
6304         em->start = start;
6305         em->orig_start = start;
6306         em->len = len;
6307 not_found_em:
6308         em->block_start = EXTENT_MAP_HOLE;
6309         set_bit(EXTENT_FLAG_VACANCY, &em->flags);
6310 insert:
6311         btrfs_release_path(path);
6312         if (em->start > start || extent_map_end(em) <= start) {
6313                 btrfs_err(root->fs_info, "bad extent! em: [%llu %llu] passed [%llu %llu]",
6314                         em->start, em->len, start, len);
6315                 err = -EIO;
6316                 goto out;
6317         }
6318
6319         err = 0;
6320         write_lock(&em_tree->lock);
6321         ret = add_extent_mapping(em_tree, em, 0);
6322         /* it is possible that someone inserted the extent into the tree
6323          * while we had the lock dropped.  It is also possible that
6324          * an overlapping map exists in the tree
6325          */
6326         if (ret == -EEXIST) {
6327                 struct extent_map *existing;
6328
6329                 ret = 0;
6330
6331                 existing = lookup_extent_mapping(em_tree, start, len);
6332                 if (existing && (existing->start > start ||
6333                     existing->start + existing->len <= start)) {
6334                         free_extent_map(existing);
6335                         existing = NULL;
6336                 }
6337                 if (!existing) {
6338                         existing = lookup_extent_mapping(em_tree, em->start,
6339                                                          em->len);
6340                         if (existing) {
6341                                 err = merge_extent_mapping(em_tree, existing,
6342                                                            em, start,
6343                                                            root->sectorsize);
6344                                 free_extent_map(existing);
6345                                 if (err) {
6346                                         free_extent_map(em);
6347                                         em = NULL;
6348                                 }
6349                         } else {
6350                                 err = -EIO;
6351                                 free_extent_map(em);
6352                                 em = NULL;
6353                         }
6354                 } else {
6355                         free_extent_map(em);
6356                         em = existing;
6357                         err = 0;
6358                 }
6359         }
6360         write_unlock(&em_tree->lock);
6361 out:
6362
6363         trace_btrfs_get_extent(root, em);
6364
6365         if (path)
6366                 btrfs_free_path(path);
6367         if (trans) {
6368                 ret = btrfs_end_transaction(trans, root);
6369                 if (!err)
6370                         err = ret;
6371         }
6372         if (err) {
6373                 free_extent_map(em);
6374                 return ERR_PTR(err);
6375         }
6376         BUG_ON(!em); /* Error is always set */
6377         return em;
6378 }
6379
6380 struct extent_map *btrfs_get_extent_fiemap(struct inode *inode, struct page *page,
6381                                            size_t pg_offset, u64 start, u64 len,
6382                                            int create)
6383 {
6384         struct extent_map *em;
6385         struct extent_map *hole_em = NULL;
6386         u64 range_start = start;
6387         u64 end;
6388         u64 found;
6389         u64 found_end;
6390         int err = 0;
6391
6392         em = btrfs_get_extent(inode, page, pg_offset, start, len, create);
6393         if (IS_ERR(em))
6394                 return em;
6395         if (em) {
6396                 /*
6397                  * if our em maps to
6398                  * -  a hole or
6399                  * -  a pre-alloc extent,
6400                  * there might actually be delalloc bytes behind it.
6401                  */
6402                 if (em->block_start != EXTENT_MAP_HOLE &&
6403                     !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
6404                         return em;
6405                 else
6406                         hole_em = em;
6407         }
6408
6409         /* check to see if we've wrapped (len == -1 or similar) */
6410         end = start + len;
6411         if (end < start)
6412                 end = (u64)-1;
6413         else
6414                 end -= 1;
6415
6416         em = NULL;
6417
6418         /* ok, we didn't find anything, lets look for delalloc */
6419         found = count_range_bits(&BTRFS_I(inode)->io_tree, &range_start,
6420                                  end, len, EXTENT_DELALLOC, 1);
6421         found_end = range_start + found;
6422         if (found_end < range_start)
6423                 found_end = (u64)-1;
6424
6425         /*
6426          * we didn't find anything useful, return
6427          * the original results from get_extent()
6428          */
6429         if (range_start > end || found_end <= start) {
6430                 em = hole_em;
6431                 hole_em = NULL;
6432                 goto out;
6433         }
6434
6435         /* adjust the range_start to make sure it doesn't
6436          * go backwards from the start they passed in
6437          */
6438         range_start = max(start, range_start);
6439         found = found_end - range_start;
6440
6441         if (found > 0) {
6442                 u64 hole_start = start;
6443                 u64 hole_len = len;
6444
6445                 em = alloc_extent_map();
6446                 if (!em) {
6447                         err = -ENOMEM;
6448                         goto out;
6449                 }
6450                 /*
6451                  * when btrfs_get_extent can't find anything it
6452                  * returns one huge hole
6453                  *
6454                  * make sure what it found really fits our range, and
6455                  * adjust to make sure it is based on the start from
6456                  * the caller
6457                  */
6458                 if (hole_em) {
6459                         u64 calc_end = extent_map_end(hole_em);
6460
6461                         if (calc_end <= start || (hole_em->start > end)) {
6462                                 free_extent_map(hole_em);
6463                                 hole_em = NULL;
6464                         } else {
6465                                 hole_start = max(hole_em->start, start);
6466                                 hole_len = calc_end - hole_start;
6467                         }
6468                 }
6469                 em->bdev = NULL;
6470                 if (hole_em && range_start > hole_start) {
6471                         /* our hole starts before our delalloc, so we
6472                          * have to return just the parts of the hole
6473                          * that go until  the delalloc starts
6474                          */
6475                         em->len = min(hole_len,
6476                                       range_start - hole_start);
6477                         em->start = hole_start;
6478                         em->orig_start = hole_start;
6479                         /*
6480                          * don't adjust block start at all,
6481                          * it is fixed at EXTENT_MAP_HOLE
6482                          */
6483                         em->block_start = hole_em->block_start;
6484                         em->block_len = hole_len;
6485                         if (test_bit(EXTENT_FLAG_PREALLOC, &hole_em->flags))
6486                                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
6487                 } else {
6488                         em->start = range_start;
6489                         em->len = found;
6490                         em->orig_start = range_start;
6491                         em->block_start = EXTENT_MAP_DELALLOC;
6492                         em->block_len = found;
6493                 }
6494         } else if (hole_em) {
6495                 return hole_em;
6496         }
6497 out:
6498
6499         free_extent_map(hole_em);
6500         if (err) {
6501                 free_extent_map(em);
6502                 return ERR_PTR(err);
6503         }
6504         return em;
6505 }
6506
6507 static struct extent_map *btrfs_new_extent_direct(struct inode *inode,
6508                                                   u64 start, u64 len)
6509 {
6510         struct btrfs_root *root = BTRFS_I(inode)->root;
6511         struct extent_map *em;
6512         struct btrfs_key ins;
6513         u64 alloc_hint;
6514         int ret;
6515
6516         alloc_hint = get_extent_allocation_hint(inode, start, len);
6517         ret = btrfs_reserve_extent(root, len, root->sectorsize, 0,
6518                                    alloc_hint, &ins, 1);
6519         if (ret)
6520                 return ERR_PTR(ret);
6521
6522         em = create_pinned_em(inode, start, ins.offset, start, ins.objectid,
6523                               ins.offset, ins.offset, ins.offset, 0);
6524         if (IS_ERR(em)) {
6525                 btrfs_free_reserved_extent(root, ins.objectid, ins.offset);
6526                 return em;
6527         }
6528
6529         ret = btrfs_add_ordered_extent_dio(inode, start, ins.objectid,
6530                                            ins.offset, ins.offset, 0);
6531         if (ret) {
6532                 btrfs_free_reserved_extent(root, ins.objectid, ins.offset);
6533                 free_extent_map(em);
6534                 return ERR_PTR(ret);
6535         }
6536
6537         return em;
6538 }
6539
6540 /*
6541  * returns 1 when the nocow is safe, < 1 on error, 0 if the
6542  * block must be cow'd
6543  */
6544 noinline int can_nocow_extent(struct inode *inode, u64 offset, u64 *len,
6545                               u64 *orig_start, u64 *orig_block_len,
6546                               u64 *ram_bytes)
6547 {
6548         struct btrfs_trans_handle *trans;
6549         struct btrfs_path *path;
6550         int ret;
6551         struct extent_buffer *leaf;
6552         struct btrfs_root *root = BTRFS_I(inode)->root;
6553         struct btrfs_file_extent_item *fi;
6554         struct btrfs_key key;
6555         u64 disk_bytenr;
6556         u64 backref_offset;
6557         u64 extent_end;
6558         u64 num_bytes;
6559         int slot;
6560         int found_type;
6561         bool nocow = (BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW);
6562
6563         path = btrfs_alloc_path();
6564         if (!path)
6565                 return -ENOMEM;
6566
6567         ret = btrfs_lookup_file_extent(NULL, root, path, btrfs_ino(inode),
6568                                        offset, 0);
6569         if (ret < 0)
6570                 goto out;
6571
6572         slot = path->slots[0];
6573         if (ret == 1) {
6574                 if (slot == 0) {
6575                         /* can't find the item, must cow */
6576                         ret = 0;
6577                         goto out;
6578                 }
6579                 slot--;
6580         }
6581         ret = 0;
6582         leaf = path->nodes[0];
6583         btrfs_item_key_to_cpu(leaf, &key, slot);
6584         if (key.objectid != btrfs_ino(inode) ||
6585             key.type != BTRFS_EXTENT_DATA_KEY) {
6586                 /* not our file or wrong item type, must cow */
6587                 goto out;
6588         }
6589
6590         if (key.offset > offset) {
6591                 /* Wrong offset, must cow */
6592                 goto out;
6593         }
6594
6595         fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
6596         found_type = btrfs_file_extent_type(leaf, fi);
6597         if (found_type != BTRFS_FILE_EXTENT_REG &&
6598             found_type != BTRFS_FILE_EXTENT_PREALLOC) {
6599                 /* not a regular extent, must cow */
6600                 goto out;
6601         }
6602
6603         if (!nocow && found_type == BTRFS_FILE_EXTENT_REG)
6604                 goto out;
6605
6606         extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
6607         if (extent_end <= offset)
6608                 goto out;
6609
6610         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
6611         if (disk_bytenr == 0)
6612                 goto out;
6613
6614         if (btrfs_file_extent_compression(leaf, fi) ||
6615             btrfs_file_extent_encryption(leaf, fi) ||
6616             btrfs_file_extent_other_encoding(leaf, fi))
6617                 goto out;
6618
6619         backref_offset = btrfs_file_extent_offset(leaf, fi);
6620
6621         if (orig_start) {
6622                 *orig_start = key.offset - backref_offset;
6623                 *orig_block_len = btrfs_file_extent_disk_num_bytes(leaf, fi);
6624                 *ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
6625         }
6626
6627         if (btrfs_extent_readonly(root, disk_bytenr))
6628                 goto out;
6629         btrfs_release_path(path);
6630
6631         /*
6632          * look for other files referencing this extent, if we
6633          * find any we must cow
6634          */
6635         trans = btrfs_join_transaction(root);
6636         if (IS_ERR(trans)) {
6637                 ret = 0;
6638                 goto out;
6639         }
6640
6641         ret = btrfs_cross_ref_exist(trans, root, btrfs_ino(inode),
6642                                     key.offset - backref_offset, disk_bytenr);
6643         btrfs_end_transaction(trans, root);
6644         if (ret) {
6645                 ret = 0;
6646                 goto out;
6647         }
6648
6649         /*
6650          * adjust disk_bytenr and num_bytes to cover just the bytes
6651          * in this extent we are about to write.  If there
6652          * are any csums in that range we have to cow in order
6653          * to keep the csums correct
6654          */
6655         disk_bytenr += backref_offset;
6656         disk_bytenr += offset - key.offset;
6657         num_bytes = min(offset + *len, extent_end) - offset;
6658         if (csum_exist_in_range(root, disk_bytenr, num_bytes))
6659                                 goto out;
6660         /*
6661          * all of the above have passed, it is safe to overwrite this extent
6662          * without cow
6663          */
6664         *len = num_bytes;
6665         ret = 1;
6666 out:
6667         btrfs_free_path(path);
6668         return ret;
6669 }
6670
6671 static int lock_extent_direct(struct inode *inode, u64 lockstart, u64 lockend,
6672                               struct extent_state **cached_state, int writing)
6673 {
6674         struct btrfs_ordered_extent *ordered;
6675         int ret = 0;
6676
6677         while (1) {
6678                 lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend,
6679                                  0, cached_state);
6680                 /*
6681                  * We're concerned with the entire range that we're going to be
6682                  * doing DIO to, so we need to make sure theres no ordered
6683                  * extents in this range.
6684                  */
6685                 ordered = btrfs_lookup_ordered_range(inode, lockstart,
6686                                                      lockend - lockstart + 1);
6687
6688                 /*
6689                  * We need to make sure there are no buffered pages in this
6690                  * range either, we could have raced between the invalidate in
6691                  * generic_file_direct_write and locking the extent.  The
6692                  * invalidate needs to happen so that reads after a write do not
6693                  * get stale data.
6694                  */
6695                 if (!ordered && (!writing ||
6696                     !test_range_bit(&BTRFS_I(inode)->io_tree,
6697                                     lockstart, lockend, EXTENT_UPTODATE, 0,
6698                                     *cached_state)))
6699                         break;
6700
6701                 unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
6702                                      cached_state, GFP_NOFS);
6703
6704                 if (ordered) {
6705                         btrfs_start_ordered_extent(inode, ordered, 1);
6706                         btrfs_put_ordered_extent(ordered);
6707                 } else {
6708                         /* Screw you mmap */
6709                         ret = filemap_write_and_wait_range(inode->i_mapping,
6710                                                            lockstart,
6711                                                            lockend);
6712                         if (ret)
6713                                 break;
6714
6715                         /*
6716                          * If we found a page that couldn't be invalidated just
6717                          * fall back to buffered.
6718                          */
6719                         ret = invalidate_inode_pages2_range(inode->i_mapping,
6720                                         lockstart >> PAGE_CACHE_SHIFT,
6721                                         lockend >> PAGE_CACHE_SHIFT);
6722                         if (ret)
6723                                 break;
6724                 }
6725
6726                 cond_resched();
6727         }
6728
6729         return ret;
6730 }
6731
6732 static struct extent_map *create_pinned_em(struct inode *inode, u64 start,
6733                                            u64 len, u64 orig_start,
6734                                            u64 block_start, u64 block_len,
6735                                            u64 orig_block_len, u64 ram_bytes,
6736                                            int type)
6737 {
6738         struct extent_map_tree *em_tree;
6739         struct extent_map *em;
6740         struct btrfs_root *root = BTRFS_I(inode)->root;
6741         int ret;
6742
6743         em_tree = &BTRFS_I(inode)->extent_tree;
6744         em = alloc_extent_map();
6745         if (!em)
6746                 return ERR_PTR(-ENOMEM);
6747
6748         em->start = start;
6749         em->orig_start = orig_start;
6750         em->mod_start = start;
6751         em->mod_len = len;
6752         em->len = len;
6753         em->block_len = block_len;
6754         em->block_start = block_start;
6755         em->bdev = root->fs_info->fs_devices->latest_bdev;
6756         em->orig_block_len = orig_block_len;
6757         em->ram_bytes = ram_bytes;
6758         em->generation = -1;
6759         set_bit(EXTENT_FLAG_PINNED, &em->flags);
6760         if (type == BTRFS_ORDERED_PREALLOC)
6761                 set_bit(EXTENT_FLAG_FILLING, &em->flags);
6762
6763         do {
6764                 btrfs_drop_extent_cache(inode, em->start,
6765                                 em->start + em->len - 1, 0);
6766                 write_lock(&em_tree->lock);
6767                 ret = add_extent_mapping(em_tree, em, 1);
6768                 write_unlock(&em_tree->lock);
6769         } while (ret == -EEXIST);
6770
6771         if (ret) {
6772                 free_extent_map(em);
6773                 return ERR_PTR(ret);
6774         }
6775
6776         return em;
6777 }
6778
6779
6780 static int btrfs_get_blocks_direct(struct inode *inode, sector_t iblock,
6781                                    struct buffer_head *bh_result, int create)
6782 {
6783         struct extent_map *em;
6784         struct btrfs_root *root = BTRFS_I(inode)->root;
6785         struct extent_state *cached_state = NULL;
6786         u64 start = iblock << inode->i_blkbits;
6787         u64 lockstart, lockend;
6788         u64 len = bh_result->b_size;
6789         int unlock_bits = EXTENT_LOCKED;
6790         int ret = 0;
6791
6792         if (create)
6793                 unlock_bits |= EXTENT_DELALLOC | EXTENT_DIRTY;
6794         else
6795                 len = min_t(u64, len, root->sectorsize);
6796
6797         lockstart = start;
6798         lockend = start + len - 1;
6799
6800         /*
6801          * If this errors out it's because we couldn't invalidate pagecache for
6802          * this range and we need to fallback to buffered.
6803          */
6804         if (lock_extent_direct(inode, lockstart, lockend, &cached_state, create))
6805                 return -ENOTBLK;
6806
6807         em = btrfs_get_extent(inode, NULL, 0, start, len, 0);
6808         if (IS_ERR(em)) {
6809                 ret = PTR_ERR(em);
6810                 goto unlock_err;
6811         }
6812
6813         /*
6814          * Ok for INLINE and COMPRESSED extents we need to fallback on buffered
6815          * io.  INLINE is special, and we could probably kludge it in here, but
6816          * it's still buffered so for safety lets just fall back to the generic
6817          * buffered path.
6818          *
6819          * For COMPRESSED we _have_ to read the entire extent in so we can
6820          * decompress it, so there will be buffering required no matter what we
6821          * do, so go ahead and fallback to buffered.
6822          *
6823          * We return -ENOTBLK because thats what makes DIO go ahead and go back
6824          * to buffered IO.  Don't blame me, this is the price we pay for using
6825          * the generic code.
6826          */
6827         if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags) ||
6828             em->block_start == EXTENT_MAP_INLINE) {
6829                 free_extent_map(em);
6830                 ret = -ENOTBLK;
6831                 goto unlock_err;
6832         }
6833
6834         /* Just a good old fashioned hole, return */
6835         if (!create && (em->block_start == EXTENT_MAP_HOLE ||
6836                         test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) {
6837                 free_extent_map(em);
6838                 goto unlock_err;
6839         }
6840
6841         /*
6842          * We don't allocate a new extent in the following cases
6843          *
6844          * 1) The inode is marked as NODATACOW.  In this case we'll just use the
6845          * existing extent.
6846          * 2) The extent is marked as PREALLOC.  We're good to go here and can
6847          * just use the extent.
6848          *
6849          */
6850         if (!create) {
6851                 len = min(len, em->len - (start - em->start));
6852                 lockstart = start + len;
6853                 goto unlock;
6854         }
6855
6856         if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags) ||
6857             ((BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW) &&
6858              em->block_start != EXTENT_MAP_HOLE)) {
6859                 int type;
6860                 int ret;
6861                 u64 block_start, orig_start, orig_block_len, ram_bytes;
6862
6863                 if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
6864                         type = BTRFS_ORDERED_PREALLOC;
6865                 else
6866                         type = BTRFS_ORDERED_NOCOW;
6867                 len = min(len, em->len - (start - em->start));
6868                 block_start = em->block_start + (start - em->start);
6869
6870                 if (can_nocow_extent(inode, start, &len, &orig_start,
6871                                      &orig_block_len, &ram_bytes) == 1) {
6872                         if (type == BTRFS_ORDERED_PREALLOC) {
6873                                 free_extent_map(em);
6874                                 em = create_pinned_em(inode, start, len,
6875                                                        orig_start,
6876                                                        block_start, len,
6877                                                        orig_block_len,
6878                                                        ram_bytes, type);
6879                                 if (IS_ERR(em))
6880                                         goto unlock_err;
6881                         }
6882
6883                         ret = btrfs_add_ordered_extent_dio(inode, start,
6884                                            block_start, len, len, type);
6885                         if (ret) {
6886                                 free_extent_map(em);
6887                                 goto unlock_err;
6888                         }
6889                         goto unlock;
6890                 }
6891         }
6892
6893         /*
6894          * this will cow the extent, reset the len in case we changed
6895          * it above
6896          */
6897         len = bh_result->b_size;
6898         free_extent_map(em);
6899         em = btrfs_new_extent_direct(inode, start, len);
6900         if (IS_ERR(em)) {
6901                 ret = PTR_ERR(em);
6902                 goto unlock_err;
6903         }
6904         len = min(len, em->len - (start - em->start));
6905 unlock:
6906         bh_result->b_blocknr = (em->block_start + (start - em->start)) >>
6907                 inode->i_blkbits;
6908         bh_result->b_size = len;
6909         bh_result->b_bdev = em->bdev;
6910         set_buffer_mapped(bh_result);
6911         if (create) {
6912                 if (!test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
6913                         set_buffer_new(bh_result);
6914
6915                 /*
6916                  * Need to update the i_size under the extent lock so buffered
6917                  * readers will get the updated i_size when we unlock.
6918                  */
6919                 if (start + len > i_size_read(inode))
6920                         i_size_write(inode, start + len);
6921
6922                 spin_lock(&BTRFS_I(inode)->lock);
6923                 BTRFS_I(inode)->outstanding_extents++;
6924                 spin_unlock(&BTRFS_I(inode)->lock);
6925
6926                 ret = set_extent_bit(&BTRFS_I(inode)->io_tree, lockstart,
6927                                      lockstart + len - 1, EXTENT_DELALLOC, NULL,
6928                                      &cached_state, GFP_NOFS);
6929                 BUG_ON(ret);
6930         }
6931
6932         /*
6933          * In the case of write we need to clear and unlock the entire range,
6934          * in the case of read we need to unlock only the end area that we
6935          * aren't using if there is any left over space.
6936          */
6937         if (lockstart < lockend) {
6938                 clear_extent_bit(&BTRFS_I(inode)->io_tree, lockstart,
6939                                  lockend, unlock_bits, 1, 0,
6940                                  &cached_state, GFP_NOFS);
6941         } else {
6942                 free_extent_state(cached_state);
6943         }
6944
6945         free_extent_map(em);
6946
6947         return 0;
6948
6949 unlock_err:
6950         clear_extent_bit(&BTRFS_I(inode)->io_tree, lockstart, lockend,
6951                          unlock_bits, 1, 0, &cached_state, GFP_NOFS);
6952         return ret;
6953 }
6954
6955 static void btrfs_endio_direct_read(struct bio *bio, int err)
6956 {
6957         struct btrfs_dio_private *dip = bio->bi_private;
6958         struct bio_vec *bvec;
6959         struct inode *inode = dip->inode;
6960         struct btrfs_root *root = BTRFS_I(inode)->root;
6961         struct bio *dio_bio;
6962         u32 *csums = (u32 *)dip->csum;
6963         u64 start;
6964         int i;
6965
6966         start = dip->logical_offset;
6967         bio_for_each_segment_all(bvec, bio, i) {
6968                 if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)) {
6969                         struct page *page = bvec->bv_page;
6970                         char *kaddr;
6971                         u32 csum = ~(u32)0;
6972                         unsigned long flags;
6973
6974                         local_irq_save(flags);
6975                         kaddr = kmap_atomic(page);
6976                         csum = btrfs_csum_data(kaddr + bvec->bv_offset,
6977                                                csum, bvec->bv_len);
6978                         btrfs_csum_final(csum, (char *)&csum);
6979                         kunmap_atomic(kaddr);
6980                         local_irq_restore(flags);
6981
6982                         flush_dcache_page(bvec->bv_page);
6983                         if (csum != csums[i]) {
6984                                 btrfs_err(root->fs_info, "csum failed ino %llu off %llu csum %u expected csum %u",
6985                                           btrfs_ino(inode), start, csum,
6986                                           csums[i]);
6987                                 err = -EIO;
6988                         }
6989                 }
6990
6991                 start += bvec->bv_len;
6992         }
6993
6994         unlock_extent(&BTRFS_I(inode)->io_tree, dip->logical_offset,
6995                       dip->logical_offset + dip->bytes - 1);
6996         dio_bio = dip->dio_bio;
6997
6998         kfree(dip);
6999
7000         /* If we had a csum failure make sure to clear the uptodate flag */
7001         if (err)
7002                 clear_bit(BIO_UPTODATE, &dio_bio->bi_flags);
7003         dio_end_io(dio_bio, err);
7004         bio_put(bio);
7005 }
7006
7007 static void btrfs_endio_direct_write(struct bio *bio, int err)
7008 {
7009         struct btrfs_dio_private *dip = bio->bi_private;
7010         struct inode *inode = dip->inode;
7011         struct btrfs_root *root = BTRFS_I(inode)->root;
7012         struct btrfs_ordered_extent *ordered = NULL;
7013         u64 ordered_offset = dip->logical_offset;
7014         u64 ordered_bytes = dip->bytes;
7015         struct bio *dio_bio;
7016         int ret;
7017
7018         if (err)
7019                 goto out_done;
7020 again:
7021         ret = btrfs_dec_test_first_ordered_pending(inode, &ordered,
7022                                                    &ordered_offset,
7023                                                    ordered_bytes, !err);
7024         if (!ret)
7025                 goto out_test;
7026
7027         ordered->work.func = finish_ordered_fn;
7028         ordered->work.flags = 0;
7029         btrfs_queue_worker(&root->fs_info->endio_write_workers,
7030                            &ordered->work);
7031 out_test:
7032         /*
7033          * our bio might span multiple ordered extents.  If we haven't
7034          * completed the accounting for the whole dio, go back and try again
7035          */
7036         if (ordered_offset < dip->logical_offset + dip->bytes) {
7037                 ordered_bytes = dip->logical_offset + dip->bytes -
7038                         ordered_offset;
7039                 ordered = NULL;
7040                 goto again;
7041         }
7042 out_done:
7043         dio_bio = dip->dio_bio;
7044
7045         kfree(dip);
7046
7047         /* If we had an error make sure to clear the uptodate flag */
7048         if (err)
7049                 clear_bit(BIO_UPTODATE, &dio_bio->bi_flags);
7050         dio_end_io(dio_bio, err);
7051         bio_put(bio);
7052 }
7053
7054 static int __btrfs_submit_bio_start_direct_io(struct inode *inode, int rw,
7055                                     struct bio *bio, int mirror_num,
7056                                     unsigned long bio_flags, u64 offset)
7057 {
7058         int ret;
7059         struct btrfs_root *root = BTRFS_I(inode)->root;
7060         ret = btrfs_csum_one_bio(root, inode, bio, offset, 1);
7061         BUG_ON(ret); /* -ENOMEM */
7062         return 0;
7063 }
7064
7065 static void btrfs_end_dio_bio(struct bio *bio, int err)
7066 {
7067         struct btrfs_dio_private *dip = bio->bi_private;
7068
7069         if (err) {
7070                 btrfs_err(BTRFS_I(dip->inode)->root->fs_info,
7071                           "direct IO failed ino %llu rw %lu sector %#Lx len %u err no %d",
7072                       btrfs_ino(dip->inode), bio->bi_rw,
7073                       (unsigned long long)bio->bi_iter.bi_sector,
7074                       bio->bi_iter.bi_size, err);
7075                 dip->errors = 1;
7076
7077                 /*
7078                  * before atomic variable goto zero, we must make sure
7079                  * dip->errors is perceived to be set.
7080                  */
7081                 smp_mb__before_atomic_dec();
7082         }
7083
7084         /* if there are more bios still pending for this dio, just exit */
7085         if (!atomic_dec_and_test(&dip->pending_bios))
7086                 goto out;
7087
7088         if (dip->errors) {
7089                 bio_io_error(dip->orig_bio);
7090         } else {
7091                 set_bit(BIO_UPTODATE, &dip->dio_bio->bi_flags);
7092                 bio_endio(dip->orig_bio, 0);
7093         }
7094 out:
7095         bio_put(bio);
7096 }
7097
7098 static struct bio *btrfs_dio_bio_alloc(struct block_device *bdev,
7099                                        u64 first_sector, gfp_t gfp_flags)
7100 {
7101         int nr_vecs = bio_get_nr_vecs(bdev);
7102         return btrfs_bio_alloc(bdev, first_sector, nr_vecs, gfp_flags);
7103 }
7104
7105 static inline int __btrfs_submit_dio_bio(struct bio *bio, struct inode *inode,
7106                                          int rw, u64 file_offset, int skip_sum,
7107                                          int async_submit)
7108 {
7109         struct btrfs_dio_private *dip = bio->bi_private;
7110         int write = rw & REQ_WRITE;
7111         struct btrfs_root *root = BTRFS_I(inode)->root;
7112         int ret;
7113
7114         if (async_submit)
7115                 async_submit = !atomic_read(&BTRFS_I(inode)->sync_writers);
7116
7117         bio_get(bio);
7118
7119         if (!write) {
7120                 ret = btrfs_bio_wq_end_io(root->fs_info, bio, 0);
7121                 if (ret)
7122                         goto err;
7123         }
7124
7125         if (skip_sum)
7126                 goto map;
7127
7128         if (write && async_submit) {
7129                 ret = btrfs_wq_submit_bio(root->fs_info,
7130                                    inode, rw, bio, 0, 0,
7131                                    file_offset,
7132                                    __btrfs_submit_bio_start_direct_io,
7133                                    __btrfs_submit_bio_done);
7134                 goto err;
7135         } else if (write) {
7136                 /*
7137                  * If we aren't doing async submit, calculate the csum of the
7138                  * bio now.
7139                  */
7140                 ret = btrfs_csum_one_bio(root, inode, bio, file_offset, 1);
7141                 if (ret)
7142                         goto err;
7143         } else if (!skip_sum) {
7144                 ret = btrfs_lookup_bio_sums_dio(root, inode, dip, bio,
7145                                                 file_offset);
7146                 if (ret)
7147                         goto err;
7148         }
7149
7150 map:
7151         ret = btrfs_map_bio(root, rw, bio, 0, async_submit);
7152 err:
7153         bio_put(bio);
7154         return ret;
7155 }
7156
7157 static int btrfs_submit_direct_hook(int rw, struct btrfs_dio_private *dip,
7158                                     int skip_sum)
7159 {
7160         struct inode *inode = dip->inode;
7161         struct btrfs_root *root = BTRFS_I(inode)->root;
7162         struct bio *bio;
7163         struct bio *orig_bio = dip->orig_bio;
7164         struct bio_vec *bvec = orig_bio->bi_io_vec;
7165         u64 start_sector = orig_bio->bi_iter.bi_sector;
7166         u64 file_offset = dip->logical_offset;
7167         u64 submit_len = 0;
7168         u64 map_length;
7169         int nr_pages = 0;
7170         int ret = 0;
7171         int async_submit = 0;
7172
7173         map_length = orig_bio->bi_iter.bi_size;
7174         ret = btrfs_map_block(root->fs_info, rw, start_sector << 9,
7175                               &map_length, NULL, 0);
7176         if (ret) {
7177                 bio_put(orig_bio);
7178                 return -EIO;
7179         }
7180
7181         if (map_length >= orig_bio->bi_iter.bi_size) {
7182                 bio = orig_bio;
7183                 goto submit;
7184         }
7185
7186         /* async crcs make it difficult to collect full stripe writes. */
7187         if (btrfs_get_alloc_profile(root, 1) &
7188             (BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6))
7189                 async_submit = 0;
7190         else
7191                 async_submit = 1;
7192
7193         bio = btrfs_dio_bio_alloc(orig_bio->bi_bdev, start_sector, GFP_NOFS);
7194         if (!bio)
7195                 return -ENOMEM;
7196         bio->bi_private = dip;
7197         bio->bi_end_io = btrfs_end_dio_bio;
7198         atomic_inc(&dip->pending_bios);
7199
7200         while (bvec <= (orig_bio->bi_io_vec + orig_bio->bi_vcnt - 1)) {
7201                 if (unlikely(map_length < submit_len + bvec->bv_len ||
7202                     bio_add_page(bio, bvec->bv_page, bvec->bv_len,
7203                                  bvec->bv_offset) < bvec->bv_len)) {
7204                         /*
7205                          * inc the count before we submit the bio so
7206                          * we know the end IO handler won't happen before
7207                          * we inc the count. Otherwise, the dip might get freed
7208                          * before we're done setting it up
7209                          */
7210                         atomic_inc(&dip->pending_bios);
7211                         ret = __btrfs_submit_dio_bio(bio, inode, rw,
7212                                                      file_offset, skip_sum,
7213                                                      async_submit);
7214                         if (ret) {
7215                                 bio_put(bio);
7216                                 atomic_dec(&dip->pending_bios);
7217                                 goto out_err;
7218                         }
7219
7220                         start_sector += submit_len >> 9;
7221                         file_offset += submit_len;
7222
7223                         submit_len = 0;
7224                         nr_pages = 0;
7225
7226                         bio = btrfs_dio_bio_alloc(orig_bio->bi_bdev,
7227                                                   start_sector, GFP_NOFS);
7228                         if (!bio)
7229                                 goto out_err;
7230                         bio->bi_private = dip;
7231                         bio->bi_end_io = btrfs_end_dio_bio;
7232
7233                         map_length = orig_bio->bi_iter.bi_size;
7234                         ret = btrfs_map_block(root->fs_info, rw,
7235                                               start_sector << 9,
7236                                               &map_length, NULL, 0);
7237                         if (ret) {
7238                                 bio_put(bio);
7239                                 goto out_err;
7240                         }
7241                 } else {
7242                         submit_len += bvec->bv_len;
7243                         nr_pages++;
7244                         bvec++;
7245                 }
7246         }
7247
7248 submit:
7249         ret = __btrfs_submit_dio_bio(bio, inode, rw, file_offset, skip_sum,
7250                                      async_submit);
7251         if (!ret)
7252                 return 0;
7253
7254         bio_put(bio);
7255 out_err:
7256         dip->errors = 1;
7257         /*
7258          * before atomic variable goto zero, we must
7259          * make sure dip->errors is perceived to be set.
7260          */
7261         smp_mb__before_atomic_dec();
7262         if (atomic_dec_and_test(&dip->pending_bios))
7263                 bio_io_error(dip->orig_bio);
7264
7265         /* bio_end_io() will handle error, so we needn't return it */
7266         return 0;
7267 }
7268
7269 static void btrfs_submit_direct(int rw, struct bio *dio_bio,
7270                                 struct inode *inode, loff_t file_offset)
7271 {
7272         struct btrfs_root *root = BTRFS_I(inode)->root;
7273         struct btrfs_dio_private *dip;
7274         struct bio *io_bio;
7275         int skip_sum;
7276         int sum_len;
7277         int write = rw & REQ_WRITE;
7278         int ret = 0;
7279         u16 csum_size;
7280
7281         skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
7282
7283         io_bio = btrfs_bio_clone(dio_bio, GFP_NOFS);
7284         if (!io_bio) {
7285                 ret = -ENOMEM;
7286                 goto free_ordered;
7287         }
7288
7289         if (!skip_sum && !write) {
7290                 csum_size = btrfs_super_csum_size(root->fs_info->super_copy);
7291                 sum_len = dio_bio->bi_iter.bi_size >>
7292                         inode->i_sb->s_blocksize_bits;
7293                 sum_len *= csum_size;
7294         } else {
7295                 sum_len = 0;
7296         }
7297
7298         dip = kmalloc(sizeof(*dip) + sum_len, GFP_NOFS);
7299         if (!dip) {
7300                 ret = -ENOMEM;
7301                 goto free_io_bio;
7302         }
7303
7304         dip->private = dio_bio->bi_private;
7305         dip->inode = inode;
7306         dip->logical_offset = file_offset;
7307         dip->bytes = dio_bio->bi_iter.bi_size;
7308         dip->disk_bytenr = (u64)dio_bio->bi_iter.bi_sector << 9;
7309         io_bio->bi_private = dip;
7310         dip->errors = 0;
7311         dip->orig_bio = io_bio;
7312         dip->dio_bio = dio_bio;
7313         atomic_set(&dip->pending_bios, 0);
7314
7315         if (write)
7316                 io_bio->bi_end_io = btrfs_endio_direct_write;
7317         else
7318                 io_bio->bi_end_io = btrfs_endio_direct_read;
7319
7320         ret = btrfs_submit_direct_hook(rw, dip, skip_sum);
7321         if (!ret)
7322                 return;
7323
7324 free_io_bio:
7325         bio_put(io_bio);
7326
7327 free_ordered:
7328         /*
7329          * If this is a write, we need to clean up the reserved space and kill
7330          * the ordered extent.
7331          */
7332         if (write) {
7333                 struct btrfs_ordered_extent *ordered;
7334                 ordered = btrfs_lookup_ordered_extent(inode, file_offset);
7335                 if (!test_bit(BTRFS_ORDERED_PREALLOC, &ordered->flags) &&
7336                     !test_bit(BTRFS_ORDERED_NOCOW, &ordered->flags))
7337                         btrfs_free_reserved_extent(root, ordered->start,
7338                                                    ordered->disk_len);
7339                 btrfs_put_ordered_extent(ordered);
7340                 btrfs_put_ordered_extent(ordered);
7341         }
7342         bio_endio(dio_bio, ret);
7343 }
7344
7345 static ssize_t check_direct_IO(struct btrfs_root *root, int rw, struct kiocb *iocb,
7346                         const struct iovec *iov, loff_t offset,
7347                         unsigned long nr_segs)
7348 {
7349         int seg;
7350         int i;
7351         size_t size;
7352         unsigned long addr;
7353         unsigned blocksize_mask = root->sectorsize - 1;
7354         ssize_t retval = -EINVAL;
7355         loff_t end = offset;
7356
7357         if (offset & blocksize_mask)
7358                 goto out;
7359
7360         /* Check the memory alignment.  Blocks cannot straddle pages */
7361         for (seg = 0; seg < nr_segs; seg++) {
7362                 addr = (unsigned long)iov[seg].iov_base;
7363                 size = iov[seg].iov_len;
7364                 end += size;
7365                 if ((addr & blocksize_mask) || (size & blocksize_mask))
7366                         goto out;
7367
7368                 /* If this is a write we don't need to check anymore */
7369                 if (rw & WRITE)
7370                         continue;
7371
7372                 /*
7373                  * Check to make sure we don't have duplicate iov_base's in this
7374                  * iovec, if so return EINVAL, otherwise we'll get csum errors
7375                  * when reading back.
7376                  */
7377                 for (i = seg + 1; i < nr_segs; i++) {
7378                         if (iov[seg].iov_base == iov[i].iov_base)
7379                                 goto out;
7380                 }
7381         }
7382         retval = 0;
7383 out:
7384         return retval;
7385 }
7386
7387 static ssize_t btrfs_direct_IO(int rw, struct kiocb *iocb,
7388                         const struct iovec *iov, loff_t offset,
7389                         unsigned long nr_segs)
7390 {
7391         struct file *file = iocb->ki_filp;
7392         struct inode *inode = file->f_mapping->host;
7393         size_t count = 0;
7394         int flags = 0;
7395         bool wakeup = true;
7396         bool relock = false;
7397         ssize_t ret;
7398
7399         if (check_direct_IO(BTRFS_I(inode)->root, rw, iocb, iov,
7400                             offset, nr_segs))
7401                 return 0;
7402
7403         atomic_inc(&inode->i_dio_count);
7404         smp_mb__after_atomic_inc();
7405
7406         /*
7407          * The generic stuff only does filemap_write_and_wait_range, which isn't
7408          * enough if we've written compressed pages to this area, so we need to
7409          * call btrfs_wait_ordered_range to make absolutely sure that any
7410          * outstanding dirty pages are on disk.
7411          */
7412         count = iov_length(iov, nr_segs);
7413         ret = btrfs_wait_ordered_range(inode, offset, count);
7414         if (ret)
7415                 return ret;
7416
7417         if (rw & WRITE) {
7418                 /*
7419                  * If the write DIO is beyond the EOF, we need update
7420                  * the isize, but it is protected by i_mutex. So we can
7421                  * not unlock the i_mutex at this case.
7422                  */
7423                 if (offset + count <= inode->i_size) {
7424                         mutex_unlock(&inode->i_mutex);
7425                         relock = true;
7426                 }
7427                 ret = btrfs_delalloc_reserve_space(inode, count);
7428                 if (ret)
7429                         goto out;
7430         } else if (unlikely(test_bit(BTRFS_INODE_READDIO_NEED_LOCK,
7431                                      &BTRFS_I(inode)->runtime_flags))) {
7432                 inode_dio_done(inode);
7433                 flags = DIO_LOCKING | DIO_SKIP_HOLES;
7434                 wakeup = false;
7435         }
7436
7437         ret = __blockdev_direct_IO(rw, iocb, inode,
7438                         BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev,
7439                         iov, offset, nr_segs, btrfs_get_blocks_direct, NULL,
7440                         btrfs_submit_direct, flags);
7441         if (rw & WRITE) {
7442                 if (ret < 0 && ret != -EIOCBQUEUED)
7443                         btrfs_delalloc_release_space(inode, count);
7444                 else if (ret >= 0 && (size_t)ret < count)
7445                         btrfs_delalloc_release_space(inode,
7446                                                      count - (size_t)ret);
7447                 else
7448                         btrfs_delalloc_release_metadata(inode, 0);
7449         }
7450 out:
7451         if (wakeup)
7452                 inode_dio_done(inode);
7453         if (relock)
7454                 mutex_lock(&inode->i_mutex);
7455
7456         return ret;
7457 }
7458
7459 #define BTRFS_FIEMAP_FLAGS      (FIEMAP_FLAG_SYNC)
7460
7461 static int btrfs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
7462                 __u64 start, __u64 len)
7463 {
7464         int     ret;
7465
7466         ret = fiemap_check_flags(fieinfo, BTRFS_FIEMAP_FLAGS);
7467         if (ret)
7468                 return ret;
7469
7470         return extent_fiemap(inode, fieinfo, start, len, btrfs_get_extent_fiemap);
7471 }
7472
7473 int btrfs_readpage(struct file *file, struct page *page)
7474 {
7475         struct extent_io_tree *tree;
7476         tree = &BTRFS_I(page->mapping->host)->io_tree;
7477         return extent_read_full_page(tree, page, btrfs_get_extent, 0);
7478 }
7479
7480 static int btrfs_writepage(struct page *page, struct writeback_control *wbc)
7481 {
7482         struct extent_io_tree *tree;
7483
7484
7485         if (current->flags & PF_MEMALLOC) {
7486                 redirty_page_for_writepage(wbc, page);
7487                 unlock_page(page);
7488                 return 0;
7489         }
7490         tree = &BTRFS_I(page->mapping->host)->io_tree;
7491         return extent_write_full_page(tree, page, btrfs_get_extent, wbc);
7492 }
7493
7494 static int btrfs_writepages(struct address_space *mapping,
7495                             struct writeback_control *wbc)
7496 {
7497         struct extent_io_tree *tree;
7498
7499         tree = &BTRFS_I(mapping->host)->io_tree;
7500         return extent_writepages(tree, mapping, btrfs_get_extent, wbc);
7501 }
7502
7503 static int
7504 btrfs_readpages(struct file *file, struct address_space *mapping,
7505                 struct list_head *pages, unsigned nr_pages)
7506 {
7507         struct extent_io_tree *tree;
7508         tree = &BTRFS_I(mapping->host)->io_tree;
7509         return extent_readpages(tree, mapping, pages, nr_pages,
7510                                 btrfs_get_extent);
7511 }
7512 static int __btrfs_releasepage(struct page *page, gfp_t gfp_flags)
7513 {
7514         struct extent_io_tree *tree;
7515         struct extent_map_tree *map;
7516         int ret;
7517
7518         tree = &BTRFS_I(page->mapping->host)->io_tree;
7519         map = &BTRFS_I(page->mapping->host)->extent_tree;
7520         ret = try_release_extent_mapping(map, tree, page, gfp_flags);
7521         if (ret == 1) {
7522                 ClearPagePrivate(page);
7523                 set_page_private(page, 0);
7524                 page_cache_release(page);
7525         }
7526         return ret;
7527 }
7528
7529 static int btrfs_releasepage(struct page *page, gfp_t gfp_flags)
7530 {
7531         if (PageWriteback(page) || PageDirty(page))
7532                 return 0;
7533         return __btrfs_releasepage(page, gfp_flags & GFP_NOFS);
7534 }
7535
7536 static void btrfs_invalidatepage(struct page *page, unsigned int offset,
7537                                  unsigned int length)
7538 {
7539         struct inode *inode = page->mapping->host;
7540         struct extent_io_tree *tree;
7541         struct btrfs_ordered_extent *ordered;
7542         struct extent_state *cached_state = NULL;
7543         u64 page_start = page_offset(page);
7544         u64 page_end = page_start + PAGE_CACHE_SIZE - 1;
7545         int inode_evicting = inode->i_state & I_FREEING;
7546
7547         /*
7548          * we have the page locked, so new writeback can't start,
7549          * and the dirty bit won't be cleared while we are here.
7550          *
7551          * Wait for IO on this page so that we can safely clear
7552          * the PagePrivate2 bit and do ordered accounting
7553          */
7554         wait_on_page_writeback(page);
7555
7556         tree = &BTRFS_I(inode)->io_tree;
7557         if (offset) {
7558                 btrfs_releasepage(page, GFP_NOFS);
7559                 return;
7560         }
7561
7562         if (!inode_evicting)
7563                 lock_extent_bits(tree, page_start, page_end, 0, &cached_state);
7564         ordered = btrfs_lookup_ordered_extent(inode, page_start);
7565         if (ordered) {
7566                 /*
7567                  * IO on this page will never be started, so we need
7568                  * to account for any ordered extents now
7569                  */
7570                 if (!inode_evicting)
7571                         clear_extent_bit(tree, page_start, page_end,
7572                                          EXTENT_DIRTY | EXTENT_DELALLOC |
7573                                          EXTENT_LOCKED | EXTENT_DO_ACCOUNTING |
7574                                          EXTENT_DEFRAG, 1, 0, &cached_state,
7575                                          GFP_NOFS);
7576                 /*
7577                  * whoever cleared the private bit is responsible
7578                  * for the finish_ordered_io
7579                  */
7580                 if (TestClearPagePrivate2(page)) {
7581                         struct btrfs_ordered_inode_tree *tree;
7582                         u64 new_len;
7583
7584                         tree = &BTRFS_I(inode)->ordered_tree;
7585
7586                         spin_lock_irq(&tree->lock);
7587                         set_bit(BTRFS_ORDERED_TRUNCATED, &ordered->flags);
7588                         new_len = page_start - ordered->file_offset;
7589                         if (new_len < ordered->truncated_len)
7590                                 ordered->truncated_len = new_len;
7591                         spin_unlock_irq(&tree->lock);
7592
7593                         if (btrfs_dec_test_ordered_pending(inode, &ordered,
7594                                                            page_start,
7595                                                            PAGE_CACHE_SIZE, 1))
7596                                 btrfs_finish_ordered_io(ordered);
7597                 }
7598                 btrfs_put_ordered_extent(ordered);
7599                 if (!inode_evicting) {
7600                         cached_state = NULL;
7601                         lock_extent_bits(tree, page_start, page_end, 0,
7602                                          &cached_state);
7603                 }
7604         }
7605
7606         if (!inode_evicting) {
7607                 clear_extent_bit(tree, page_start, page_end,
7608                                  EXTENT_LOCKED | EXTENT_DIRTY |
7609                                  EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING |
7610                                  EXTENT_DEFRAG, 1, 1,
7611                                  &cached_state, GFP_NOFS);
7612
7613                 __btrfs_releasepage(page, GFP_NOFS);
7614         }
7615
7616         ClearPageChecked(page);
7617         if (PagePrivate(page)) {
7618                 ClearPagePrivate(page);
7619                 set_page_private(page, 0);
7620                 page_cache_release(page);
7621         }
7622 }
7623
7624 /*
7625  * btrfs_page_mkwrite() is not allowed to change the file size as it gets
7626  * called from a page fault handler when a page is first dirtied. Hence we must
7627  * be careful to check for EOF conditions here. We set the page up correctly
7628  * for a written page which means we get ENOSPC checking when writing into
7629  * holes and correct delalloc and unwritten extent mapping on filesystems that
7630  * support these features.
7631  *
7632  * We are not allowed to take the i_mutex here so we have to play games to
7633  * protect against truncate races as the page could now be beyond EOF.  Because
7634  * vmtruncate() writes the inode size before removing pages, once we have the
7635  * page lock we can determine safely if the page is beyond EOF. If it is not
7636  * beyond EOF, then the page is guaranteed safe against truncation until we
7637  * unlock the page.
7638  */
7639 int btrfs_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
7640 {
7641         struct page *page = vmf->page;
7642         struct inode *inode = file_inode(vma->vm_file);
7643         struct btrfs_root *root = BTRFS_I(inode)->root;
7644         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
7645         struct btrfs_ordered_extent *ordered;
7646         struct extent_state *cached_state = NULL;
7647         char *kaddr;
7648         unsigned long zero_start;
7649         loff_t size;
7650         int ret;
7651         int reserved = 0;
7652         u64 page_start;
7653         u64 page_end;
7654
7655         sb_start_pagefault(inode->i_sb);
7656         ret  = btrfs_delalloc_reserve_space(inode, PAGE_CACHE_SIZE);
7657         if (!ret) {
7658                 ret = file_update_time(vma->vm_file);
7659                 reserved = 1;
7660         }
7661         if (ret) {
7662                 if (ret == -ENOMEM)
7663                         ret = VM_FAULT_OOM;
7664                 else /* -ENOSPC, -EIO, etc */
7665                         ret = VM_FAULT_SIGBUS;
7666                 if (reserved)
7667                         goto out;
7668                 goto out_noreserve;
7669         }
7670
7671         ret = VM_FAULT_NOPAGE; /* make the VM retry the fault */
7672 again:
7673         lock_page(page);
7674         size = i_size_read(inode);
7675         page_start = page_offset(page);
7676         page_end = page_start + PAGE_CACHE_SIZE - 1;
7677
7678         if ((page->mapping != inode->i_mapping) ||
7679             (page_start >= size)) {
7680                 /* page got truncated out from underneath us */
7681                 goto out_unlock;
7682         }
7683         wait_on_page_writeback(page);
7684
7685         lock_extent_bits(io_tree, page_start, page_end, 0, &cached_state);
7686         set_page_extent_mapped(page);
7687
7688         /*
7689          * we can't set the delalloc bits if there are pending ordered
7690          * extents.  Drop our locks and wait for them to finish
7691          */
7692         ordered = btrfs_lookup_ordered_extent(inode, page_start);
7693         if (ordered) {
7694                 unlock_extent_cached(io_tree, page_start, page_end,
7695                                      &cached_state, GFP_NOFS);
7696                 unlock_page(page);
7697                 btrfs_start_ordered_extent(inode, ordered, 1);
7698                 btrfs_put_ordered_extent(ordered);
7699                 goto again;
7700         }
7701
7702         /*
7703          * XXX - page_mkwrite gets called every time the page is dirtied, even
7704          * if it was already dirty, so for space accounting reasons we need to
7705          * clear any delalloc bits for the range we are fixing to save.  There
7706          * is probably a better way to do this, but for now keep consistent with
7707          * prepare_pages in the normal write path.
7708          */
7709         clear_extent_bit(&BTRFS_I(inode)->io_tree, page_start, page_end,
7710                           EXTENT_DIRTY | EXTENT_DELALLOC |
7711                           EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
7712                           0, 0, &cached_state, GFP_NOFS);
7713
7714         ret = btrfs_set_extent_delalloc(inode, page_start, page_end,
7715                                         &cached_state);
7716         if (ret) {
7717                 unlock_extent_cached(io_tree, page_start, page_end,
7718                                      &cached_state, GFP_NOFS);
7719                 ret = VM_FAULT_SIGBUS;
7720                 goto out_unlock;
7721         }
7722         ret = 0;
7723
7724         /* page is wholly or partially inside EOF */
7725         if (page_start + PAGE_CACHE_SIZE > size)
7726                 zero_start = size & ~PAGE_CACHE_MASK;
7727         else
7728                 zero_start = PAGE_CACHE_SIZE;
7729
7730         if (zero_start != PAGE_CACHE_SIZE) {
7731                 kaddr = kmap(page);
7732                 memset(kaddr + zero_start, 0, PAGE_CACHE_SIZE - zero_start);
7733                 flush_dcache_page(page);
7734                 kunmap(page);
7735         }
7736         ClearPageChecked(page);
7737         set_page_dirty(page);
7738         SetPageUptodate(page);
7739
7740         BTRFS_I(inode)->last_trans = root->fs_info->generation;
7741         BTRFS_I(inode)->last_sub_trans = BTRFS_I(inode)->root->log_transid;
7742         BTRFS_I(inode)->last_log_commit = BTRFS_I(inode)->root->last_log_commit;
7743
7744         unlock_extent_cached(io_tree, page_start, page_end, &cached_state, GFP_NOFS);
7745
7746 out_unlock:
7747         if (!ret) {
7748                 sb_end_pagefault(inode->i_sb);
7749                 return VM_FAULT_LOCKED;
7750         }
7751         unlock_page(page);
7752 out:
7753         btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
7754 out_noreserve:
7755         sb_end_pagefault(inode->i_sb);
7756         return ret;
7757 }
7758
7759 static int btrfs_truncate(struct inode *inode)
7760 {
7761         struct btrfs_root *root = BTRFS_I(inode)->root;
7762         struct btrfs_block_rsv *rsv;
7763         int ret = 0;
7764         int err = 0;
7765         struct btrfs_trans_handle *trans;
7766         u64 mask = root->sectorsize - 1;
7767         u64 min_size = btrfs_calc_trunc_metadata_size(root, 1);
7768
7769         ret = btrfs_wait_ordered_range(inode, inode->i_size & (~mask),
7770                                        (u64)-1);
7771         if (ret)
7772                 return ret;
7773
7774         /*
7775          * Yes ladies and gentelment, this is indeed ugly.  The fact is we have
7776          * 3 things going on here
7777          *
7778          * 1) We need to reserve space for our orphan item and the space to
7779          * delete our orphan item.  Lord knows we don't want to have a dangling
7780          * orphan item because we didn't reserve space to remove it.
7781          *
7782          * 2) We need to reserve space to update our inode.
7783          *
7784          * 3) We need to have something to cache all the space that is going to
7785          * be free'd up by the truncate operation, but also have some slack
7786          * space reserved in case it uses space during the truncate (thank you
7787          * very much snapshotting).
7788          *
7789          * And we need these to all be seperate.  The fact is we can use alot of
7790          * space doing the truncate, and we have no earthly idea how much space
7791          * we will use, so we need the truncate reservation to be seperate so it
7792          * doesn't end up using space reserved for updating the inode or
7793          * removing the orphan item.  We also need to be able to stop the
7794          * transaction and start a new one, which means we need to be able to
7795          * update the inode several times, and we have no idea of knowing how
7796          * many times that will be, so we can't just reserve 1 item for the
7797          * entirety of the opration, so that has to be done seperately as well.
7798          * Then there is the orphan item, which does indeed need to be held on
7799          * to for the whole operation, and we need nobody to touch this reserved
7800          * space except the orphan code.
7801          *
7802          * So that leaves us with
7803          *
7804          * 1) root->orphan_block_rsv - for the orphan deletion.
7805          * 2) rsv - for the truncate reservation, which we will steal from the
7806          * transaction reservation.
7807          * 3) fs_info->trans_block_rsv - this will have 1 items worth left for
7808          * updating the inode.
7809          */
7810         rsv = btrfs_alloc_block_rsv(root, BTRFS_BLOCK_RSV_TEMP);
7811         if (!rsv)
7812                 return -ENOMEM;
7813         rsv->size = min_size;
7814         rsv->failfast = 1;
7815
7816         /*
7817          * 1 for the truncate slack space
7818          * 1 for updating the inode.
7819          */
7820         trans = btrfs_start_transaction(root, 2);
7821         if (IS_ERR(trans)) {
7822                 err = PTR_ERR(trans);
7823                 goto out;
7824         }
7825
7826         /* Migrate the slack space for the truncate to our reserve */
7827         ret = btrfs_block_rsv_migrate(&root->fs_info->trans_block_rsv, rsv,
7828                                       min_size);
7829         BUG_ON(ret);
7830
7831         /*
7832          * setattr is responsible for setting the ordered_data_close flag,
7833          * but that is only tested during the last file release.  That
7834          * could happen well after the next commit, leaving a great big
7835          * window where new writes may get lost if someone chooses to write
7836          * to this file after truncating to zero
7837          *
7838          * The inode doesn't have any dirty data here, and so if we commit
7839          * this is a noop.  If someone immediately starts writing to the inode
7840          * it is very likely we'll catch some of their writes in this
7841          * transaction, and the commit will find this file on the ordered
7842          * data list with good things to send down.
7843          *
7844          * This is a best effort solution, there is still a window where
7845          * using truncate to replace the contents of the file will
7846          * end up with a zero length file after a crash.
7847          */
7848         if (inode->i_size == 0 && test_bit(BTRFS_INODE_ORDERED_DATA_CLOSE,
7849                                            &BTRFS_I(inode)->runtime_flags))
7850                 btrfs_add_ordered_operation(trans, root, inode);
7851
7852         /*
7853          * So if we truncate and then write and fsync we normally would just
7854          * write the extents that changed, which is a problem if we need to
7855          * first truncate that entire inode.  So set this flag so we write out
7856          * all of the extents in the inode to the sync log so we're completely
7857          * safe.
7858          */
7859         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
7860         trans->block_rsv = rsv;
7861
7862         while (1) {
7863                 ret = btrfs_truncate_inode_items(trans, root, inode,
7864                                                  inode->i_size,
7865                                                  BTRFS_EXTENT_DATA_KEY);
7866                 if (ret != -ENOSPC) {
7867                         err = ret;
7868                         break;
7869                 }
7870
7871                 trans->block_rsv = &root->fs_info->trans_block_rsv;
7872                 ret = btrfs_update_inode(trans, root, inode);
7873                 if (ret) {
7874                         err = ret;
7875                         break;
7876                 }
7877
7878                 btrfs_end_transaction(trans, root);
7879                 btrfs_btree_balance_dirty(root);
7880
7881                 trans = btrfs_start_transaction(root, 2);
7882                 if (IS_ERR(trans)) {
7883                         ret = err = PTR_ERR(trans);
7884                         trans = NULL;
7885                         break;
7886                 }
7887
7888                 ret = btrfs_block_rsv_migrate(&root->fs_info->trans_block_rsv,
7889                                               rsv, min_size);
7890                 BUG_ON(ret);    /* shouldn't happen */
7891                 trans->block_rsv = rsv;
7892         }
7893
7894         if (ret == 0 && inode->i_nlink > 0) {
7895                 trans->block_rsv = root->orphan_block_rsv;
7896                 ret = btrfs_orphan_del(trans, inode);
7897                 if (ret)
7898                         err = ret;
7899         }
7900
7901         if (trans) {
7902                 trans->block_rsv = &root->fs_info->trans_block_rsv;
7903                 ret = btrfs_update_inode(trans, root, inode);
7904                 if (ret && !err)
7905                         err = ret;
7906
7907                 ret = btrfs_end_transaction(trans, root);
7908                 btrfs_btree_balance_dirty(root);
7909         }
7910
7911 out:
7912         btrfs_free_block_rsv(root, rsv);
7913
7914         if (ret && !err)
7915                 err = ret;
7916
7917         return err;
7918 }
7919
7920 /*
7921  * create a new subvolume directory/inode (helper for the ioctl).
7922  */
7923 int btrfs_create_subvol_root(struct btrfs_trans_handle *trans,
7924                              struct btrfs_root *new_root,
7925                              struct btrfs_root *parent_root,
7926                              u64 new_dirid)
7927 {
7928         struct inode *inode;
7929         int err;
7930         u64 index = 0;
7931
7932         inode = btrfs_new_inode(trans, new_root, NULL, "..", 2,
7933                                 new_dirid, new_dirid,
7934                                 S_IFDIR | (~current_umask() & S_IRWXUGO),
7935                                 &index);
7936         if (IS_ERR(inode))
7937                 return PTR_ERR(inode);
7938         inode->i_op = &btrfs_dir_inode_operations;
7939         inode->i_fop = &btrfs_dir_file_operations;
7940
7941         set_nlink(inode, 1);
7942         btrfs_i_size_write(inode, 0);
7943
7944         err = btrfs_subvol_inherit_props(trans, new_root, parent_root);
7945         if (err)
7946                 btrfs_err(new_root->fs_info,
7947                           "error inheriting subvolume %llu properties: %d\n",
7948                           new_root->root_key.objectid, err);
7949
7950         err = btrfs_update_inode(trans, new_root, inode);
7951
7952         iput(inode);
7953         return err;
7954 }
7955
7956 struct inode *btrfs_alloc_inode(struct super_block *sb)
7957 {
7958         struct btrfs_inode *ei;
7959         struct inode *inode;
7960
7961         ei = kmem_cache_alloc(btrfs_inode_cachep, GFP_NOFS);
7962         if (!ei)
7963                 return NULL;
7964
7965         ei->root = NULL;
7966         ei->generation = 0;
7967         ei->last_trans = 0;
7968         ei->last_sub_trans = 0;
7969         ei->logged_trans = 0;
7970         ei->delalloc_bytes = 0;
7971         ei->disk_i_size = 0;
7972         ei->flags = 0;
7973         ei->csum_bytes = 0;
7974         ei->index_cnt = (u64)-1;
7975         ei->dir_index = 0;
7976         ei->last_unlink_trans = 0;
7977         ei->last_log_commit = 0;
7978
7979         spin_lock_init(&ei->lock);
7980         ei->outstanding_extents = 0;
7981         ei->reserved_extents = 0;
7982
7983         ei->runtime_flags = 0;
7984         ei->force_compress = BTRFS_COMPRESS_NONE;
7985
7986         ei->delayed_node = NULL;
7987
7988         inode = &ei->vfs_inode;
7989         extent_map_tree_init(&ei->extent_tree);
7990         extent_io_tree_init(&ei->io_tree, &inode->i_data);
7991         extent_io_tree_init(&ei->io_failure_tree, &inode->i_data);
7992         ei->io_tree.track_uptodate = 1;
7993         ei->io_failure_tree.track_uptodate = 1;
7994         atomic_set(&ei->sync_writers, 0);
7995         mutex_init(&ei->log_mutex);
7996         mutex_init(&ei->delalloc_mutex);
7997         btrfs_ordered_inode_tree_init(&ei->ordered_tree);
7998         INIT_LIST_HEAD(&ei->delalloc_inodes);
7999         INIT_LIST_HEAD(&ei->ordered_operations);
8000         RB_CLEAR_NODE(&ei->rb_node);
8001
8002         return inode;
8003 }
8004
8005 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
8006 void btrfs_test_destroy_inode(struct inode *inode)
8007 {
8008         btrfs_drop_extent_cache(inode, 0, (u64)-1, 0);
8009         kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
8010 }
8011 #endif
8012
8013 static void btrfs_i_callback(struct rcu_head *head)
8014 {
8015         struct inode *inode = container_of(head, struct inode, i_rcu);
8016         kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
8017 }
8018
8019 void btrfs_destroy_inode(struct inode *inode)
8020 {
8021         struct btrfs_ordered_extent *ordered;
8022         struct btrfs_root *root = BTRFS_I(inode)->root;
8023
8024         WARN_ON(!hlist_empty(&inode->i_dentry));
8025         WARN_ON(inode->i_data.nrpages);
8026         WARN_ON(BTRFS_I(inode)->outstanding_extents);
8027         WARN_ON(BTRFS_I(inode)->reserved_extents);
8028         WARN_ON(BTRFS_I(inode)->delalloc_bytes);
8029         WARN_ON(BTRFS_I(inode)->csum_bytes);
8030
8031         /*
8032          * This can happen where we create an inode, but somebody else also
8033          * created the same inode and we need to destroy the one we already
8034          * created.
8035          */
8036         if (!root)
8037                 goto free;
8038
8039         /*
8040          * Make sure we're properly removed from the ordered operation
8041          * lists.
8042          */
8043         smp_mb();
8044         if (!list_empty(&BTRFS_I(inode)->ordered_operations)) {
8045                 spin_lock(&root->fs_info->ordered_root_lock);
8046                 list_del_init(&BTRFS_I(inode)->ordered_operations);
8047                 spin_unlock(&root->fs_info->ordered_root_lock);
8048         }
8049
8050         if (test_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
8051                      &BTRFS_I(inode)->runtime_flags)) {
8052                 btrfs_info(root->fs_info, "inode %llu still on the orphan list",
8053                         btrfs_ino(inode));
8054                 atomic_dec(&root->orphan_inodes);
8055         }
8056
8057         while (1) {
8058                 ordered = btrfs_lookup_first_ordered_extent(inode, (u64)-1);
8059                 if (!ordered)
8060                         break;
8061                 else {
8062                         btrfs_err(root->fs_info, "found ordered extent %llu %llu on inode cleanup",
8063                                 ordered->file_offset, ordered->len);
8064                         btrfs_remove_ordered_extent(inode, ordered);
8065                         btrfs_put_ordered_extent(ordered);
8066                         btrfs_put_ordered_extent(ordered);
8067                 }
8068         }
8069         inode_tree_del(inode);
8070         btrfs_drop_extent_cache(inode, 0, (u64)-1, 0);
8071 free:
8072         call_rcu(&inode->i_rcu, btrfs_i_callback);
8073 }
8074
8075 int btrfs_drop_inode(struct inode *inode)
8076 {
8077         struct btrfs_root *root = BTRFS_I(inode)->root;
8078
8079         if (root == NULL)
8080                 return 1;
8081
8082         /* the snap/subvol tree is on deleting */
8083         if (btrfs_root_refs(&root->root_item) == 0)
8084                 return 1;
8085         else
8086                 return generic_drop_inode(inode);
8087 }
8088
8089 static void init_once(void *foo)
8090 {
8091         struct btrfs_inode *ei = (struct btrfs_inode *) foo;
8092
8093         inode_init_once(&ei->vfs_inode);
8094 }
8095
8096 void btrfs_destroy_cachep(void)
8097 {
8098         /*
8099          * Make sure all delayed rcu free inodes are flushed before we
8100          * destroy cache.
8101          */
8102         rcu_barrier();
8103         if (btrfs_inode_cachep)
8104                 kmem_cache_destroy(btrfs_inode_cachep);
8105         if (btrfs_trans_handle_cachep)
8106                 kmem_cache_destroy(btrfs_trans_handle_cachep);
8107         if (btrfs_transaction_cachep)
8108                 kmem_cache_destroy(btrfs_transaction_cachep);
8109         if (btrfs_path_cachep)
8110                 kmem_cache_destroy(btrfs_path_cachep);
8111         if (btrfs_free_space_cachep)
8112                 kmem_cache_destroy(btrfs_free_space_cachep);
8113         if (btrfs_delalloc_work_cachep)
8114                 kmem_cache_destroy(btrfs_delalloc_work_cachep);
8115 }
8116
8117 int btrfs_init_cachep(void)
8118 {
8119         btrfs_inode_cachep = kmem_cache_create("btrfs_inode",
8120                         sizeof(struct btrfs_inode), 0,
8121                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, init_once);
8122         if (!btrfs_inode_cachep)
8123                 goto fail;
8124
8125         btrfs_trans_handle_cachep = kmem_cache_create("btrfs_trans_handle",
8126                         sizeof(struct btrfs_trans_handle), 0,
8127                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
8128         if (!btrfs_trans_handle_cachep)
8129                 goto fail;
8130
8131         btrfs_transaction_cachep = kmem_cache_create("btrfs_transaction",
8132                         sizeof(struct btrfs_transaction), 0,
8133                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
8134         if (!btrfs_transaction_cachep)
8135                 goto fail;
8136
8137         btrfs_path_cachep = kmem_cache_create("btrfs_path",
8138                         sizeof(struct btrfs_path), 0,
8139                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
8140         if (!btrfs_path_cachep)
8141                 goto fail;
8142
8143         btrfs_free_space_cachep = kmem_cache_create("btrfs_free_space",
8144                         sizeof(struct btrfs_free_space), 0,
8145                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
8146         if (!btrfs_free_space_cachep)
8147                 goto fail;
8148
8149         btrfs_delalloc_work_cachep = kmem_cache_create("btrfs_delalloc_work",
8150                         sizeof(struct btrfs_delalloc_work), 0,
8151                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD,
8152                         NULL);
8153         if (!btrfs_delalloc_work_cachep)
8154                 goto fail;
8155
8156         return 0;
8157 fail:
8158         btrfs_destroy_cachep();
8159         return -ENOMEM;
8160 }
8161
8162 static int btrfs_getattr(struct vfsmount *mnt,
8163                          struct dentry *dentry, struct kstat *stat)
8164 {
8165         u64 delalloc_bytes;
8166         struct inode *inode = dentry->d_inode;
8167         u32 blocksize = inode->i_sb->s_blocksize;
8168
8169         generic_fillattr(inode, stat);
8170         stat->dev = BTRFS_I(inode)->root->anon_dev;
8171         stat->blksize = PAGE_CACHE_SIZE;
8172
8173         spin_lock(&BTRFS_I(inode)->lock);
8174         delalloc_bytes = BTRFS_I(inode)->delalloc_bytes;
8175         spin_unlock(&BTRFS_I(inode)->lock);
8176         stat->blocks = (ALIGN(inode_get_bytes(inode), blocksize) +
8177                         ALIGN(delalloc_bytes, blocksize)) >> 9;
8178         return 0;
8179 }
8180
8181 static int btrfs_rename(struct inode *old_dir, struct dentry *old_dentry,
8182                            struct inode *new_dir, struct dentry *new_dentry)
8183 {
8184         struct btrfs_trans_handle *trans;
8185         struct btrfs_root *root = BTRFS_I(old_dir)->root;
8186         struct btrfs_root *dest = BTRFS_I(new_dir)->root;
8187         struct inode *new_inode = new_dentry->d_inode;
8188         struct inode *old_inode = old_dentry->d_inode;
8189         struct timespec ctime = CURRENT_TIME;
8190         u64 index = 0;
8191         u64 root_objectid;
8192         int ret;
8193         u64 old_ino = btrfs_ino(old_inode);
8194
8195         if (btrfs_ino(new_dir) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
8196                 return -EPERM;
8197
8198         /* we only allow rename subvolume link between subvolumes */
8199         if (old_ino != BTRFS_FIRST_FREE_OBJECTID && root != dest)
8200                 return -EXDEV;
8201
8202         if (old_ino == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID ||
8203             (new_inode && btrfs_ino(new_inode) == BTRFS_FIRST_FREE_OBJECTID))
8204                 return -ENOTEMPTY;
8205
8206         if (S_ISDIR(old_inode->i_mode) && new_inode &&
8207             new_inode->i_size > BTRFS_EMPTY_DIR_SIZE)
8208                 return -ENOTEMPTY;
8209
8210
8211         /* check for collisions, even if the  name isn't there */
8212         ret = btrfs_check_dir_item_collision(dest, new_dir->i_ino,
8213                              new_dentry->d_name.name,
8214                              new_dentry->d_name.len);
8215
8216         if (ret) {
8217                 if (ret == -EEXIST) {
8218                         /* we shouldn't get
8219                          * eexist without a new_inode */
8220                         if (WARN_ON(!new_inode)) {
8221                                 return ret;
8222                         }
8223                 } else {
8224                         /* maybe -EOVERFLOW */
8225                         return ret;
8226                 }
8227         }
8228         ret = 0;
8229
8230         /*
8231          * we're using rename to replace one file with another.
8232          * and the replacement file is large.  Start IO on it now so
8233          * we don't add too much work to the end of the transaction
8234          */
8235         if (new_inode && S_ISREG(old_inode->i_mode) && new_inode->i_size &&
8236             old_inode->i_size > BTRFS_ORDERED_OPERATIONS_FLUSH_LIMIT)
8237                 filemap_flush(old_inode->i_mapping);
8238
8239         /* close the racy window with snapshot create/destroy ioctl */
8240         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
8241                 down_read(&root->fs_info->subvol_sem);
8242         /*
8243          * We want to reserve the absolute worst case amount of items.  So if
8244          * both inodes are subvols and we need to unlink them then that would
8245          * require 4 item modifications, but if they are both normal inodes it
8246          * would require 5 item modifications, so we'll assume their normal
8247          * inodes.  So 5 * 2 is 10, plus 1 for the new link, so 11 total items
8248          * should cover the worst case number of items we'll modify.
8249          */
8250         trans = btrfs_start_transaction(root, 11);
8251         if (IS_ERR(trans)) {
8252                 ret = PTR_ERR(trans);
8253                 goto out_notrans;
8254         }
8255
8256         if (dest != root)
8257                 btrfs_record_root_in_trans(trans, dest);
8258
8259         ret = btrfs_set_inode_index(new_dir, &index);
8260         if (ret)
8261                 goto out_fail;
8262
8263         BTRFS_I(old_inode)->dir_index = 0ULL;
8264         if (unlikely(old_ino == BTRFS_FIRST_FREE_OBJECTID)) {
8265                 /* force full log commit if subvolume involved. */
8266                 root->fs_info->last_trans_log_full_commit = trans->transid;
8267         } else {
8268                 ret = btrfs_insert_inode_ref(trans, dest,
8269                                              new_dentry->d_name.name,
8270                                              new_dentry->d_name.len,
8271                                              old_ino,
8272                                              btrfs_ino(new_dir), index);
8273                 if (ret)
8274                         goto out_fail;
8275                 /*
8276                  * this is an ugly little race, but the rename is required
8277                  * to make sure that if we crash, the inode is either at the
8278                  * old name or the new one.  pinning the log transaction lets
8279                  * us make sure we don't allow a log commit to come in after
8280                  * we unlink the name but before we add the new name back in.
8281                  */
8282                 btrfs_pin_log_trans(root);
8283         }
8284         /*
8285          * make sure the inode gets flushed if it is replacing
8286          * something.
8287          */
8288         if (new_inode && new_inode->i_size && S_ISREG(old_inode->i_mode))
8289                 btrfs_add_ordered_operation(trans, root, old_inode);
8290
8291         inode_inc_iversion(old_dir);
8292         inode_inc_iversion(new_dir);
8293         inode_inc_iversion(old_inode);
8294         old_dir->i_ctime = old_dir->i_mtime = ctime;
8295         new_dir->i_ctime = new_dir->i_mtime = ctime;
8296         old_inode->i_ctime = ctime;
8297
8298         if (old_dentry->d_parent != new_dentry->d_parent)
8299                 btrfs_record_unlink_dir(trans, old_dir, old_inode, 1);
8300
8301         if (unlikely(old_ino == BTRFS_FIRST_FREE_OBJECTID)) {
8302                 root_objectid = BTRFS_I(old_inode)->root->root_key.objectid;
8303                 ret = btrfs_unlink_subvol(trans, root, old_dir, root_objectid,
8304                                         old_dentry->d_name.name,
8305                                         old_dentry->d_name.len);
8306         } else {
8307                 ret = __btrfs_unlink_inode(trans, root, old_dir,
8308                                         old_dentry->d_inode,
8309                                         old_dentry->d_name.name,
8310                                         old_dentry->d_name.len);
8311                 if (!ret)
8312                         ret = btrfs_update_inode(trans, root, old_inode);
8313         }
8314         if (ret) {
8315                 btrfs_abort_transaction(trans, root, ret);
8316                 goto out_fail;
8317         }
8318
8319         if (new_inode) {
8320                 inode_inc_iversion(new_inode);
8321                 new_inode->i_ctime = CURRENT_TIME;
8322                 if (unlikely(btrfs_ino(new_inode) ==
8323                              BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
8324                         root_objectid = BTRFS_I(new_inode)->location.objectid;
8325                         ret = btrfs_unlink_subvol(trans, dest, new_dir,
8326                                                 root_objectid,
8327                                                 new_dentry->d_name.name,
8328                                                 new_dentry->d_name.len);
8329                         BUG_ON(new_inode->i_nlink == 0);
8330                 } else {
8331                         ret = btrfs_unlink_inode(trans, dest, new_dir,
8332                                                  new_dentry->d_inode,
8333                                                  new_dentry->d_name.name,
8334                                                  new_dentry->d_name.len);
8335                 }
8336                 if (!ret && new_inode->i_nlink == 0)
8337                         ret = btrfs_orphan_add(trans, new_dentry->d_inode);
8338                 if (ret) {
8339                         btrfs_abort_transaction(trans, root, ret);
8340                         goto out_fail;
8341                 }
8342         }
8343
8344         ret = btrfs_add_link(trans, new_dir, old_inode,
8345                              new_dentry->d_name.name,
8346                              new_dentry->d_name.len, 0, index);
8347         if (ret) {
8348                 btrfs_abort_transaction(trans, root, ret);
8349                 goto out_fail;
8350         }
8351
8352         if (old_inode->i_nlink == 1)
8353                 BTRFS_I(old_inode)->dir_index = index;
8354
8355         if (old_ino != BTRFS_FIRST_FREE_OBJECTID) {
8356                 struct dentry *parent = new_dentry->d_parent;
8357                 btrfs_log_new_name(trans, old_inode, old_dir, parent);
8358                 btrfs_end_log_trans(root);
8359         }
8360 out_fail:
8361         btrfs_end_transaction(trans, root);
8362 out_notrans:
8363         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
8364                 up_read(&root->fs_info->subvol_sem);
8365
8366         return ret;
8367 }
8368
8369 static void btrfs_run_delalloc_work(struct btrfs_work *work)
8370 {
8371         struct btrfs_delalloc_work *delalloc_work;
8372         struct inode *inode;
8373
8374         delalloc_work = container_of(work, struct btrfs_delalloc_work,
8375                                      work);
8376         inode = delalloc_work->inode;
8377         if (delalloc_work->wait) {
8378                 btrfs_wait_ordered_range(inode, 0, (u64)-1);
8379         } else {
8380                 filemap_flush(inode->i_mapping);
8381                 if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
8382                              &BTRFS_I(inode)->runtime_flags))
8383                         filemap_flush(inode->i_mapping);
8384         }
8385
8386         if (delalloc_work->delay_iput)
8387                 btrfs_add_delayed_iput(inode);
8388         else
8389                 iput(inode);
8390         complete(&delalloc_work->completion);
8391 }
8392
8393 struct btrfs_delalloc_work *btrfs_alloc_delalloc_work(struct inode *inode,
8394                                                     int wait, int delay_iput)
8395 {
8396         struct btrfs_delalloc_work *work;
8397
8398         work = kmem_cache_zalloc(btrfs_delalloc_work_cachep, GFP_NOFS);
8399         if (!work)
8400                 return NULL;
8401
8402         init_completion(&work->completion);
8403         INIT_LIST_HEAD(&work->list);
8404         work->inode = inode;
8405         work->wait = wait;
8406         work->delay_iput = delay_iput;
8407         work->work.func = btrfs_run_delalloc_work;
8408
8409         return work;
8410 }
8411
8412 void btrfs_wait_and_free_delalloc_work(struct btrfs_delalloc_work *work)
8413 {
8414         wait_for_completion(&work->completion);
8415         kmem_cache_free(btrfs_delalloc_work_cachep, work);
8416 }
8417
8418 /*
8419  * some fairly slow code that needs optimization. This walks the list
8420  * of all the inodes with pending delalloc and forces them to disk.
8421  */
8422 static int __start_delalloc_inodes(struct btrfs_root *root, int delay_iput)
8423 {
8424         struct btrfs_inode *binode;
8425         struct inode *inode;
8426         struct btrfs_delalloc_work *work, *next;
8427         struct list_head works;
8428         struct list_head splice;
8429         int ret = 0;
8430
8431         INIT_LIST_HEAD(&works);
8432         INIT_LIST_HEAD(&splice);
8433
8434         spin_lock(&root->delalloc_lock);
8435         list_splice_init(&root->delalloc_inodes, &splice);
8436         while (!list_empty(&splice)) {
8437                 binode = list_entry(splice.next, struct btrfs_inode,
8438                                     delalloc_inodes);
8439
8440                 list_move_tail(&binode->delalloc_inodes,
8441                                &root->delalloc_inodes);
8442                 inode = igrab(&binode->vfs_inode);
8443                 if (!inode) {
8444                         cond_resched_lock(&root->delalloc_lock);
8445                         continue;
8446                 }
8447                 spin_unlock(&root->delalloc_lock);
8448
8449                 work = btrfs_alloc_delalloc_work(inode, 0, delay_iput);
8450                 if (unlikely(!work)) {
8451                         if (delay_iput)
8452                                 btrfs_add_delayed_iput(inode);
8453                         else
8454                                 iput(inode);
8455                         ret = -ENOMEM;
8456                         goto out;
8457                 }
8458                 list_add_tail(&work->list, &works);
8459                 btrfs_queue_worker(&root->fs_info->flush_workers,
8460                                    &work->work);
8461
8462                 cond_resched();
8463                 spin_lock(&root->delalloc_lock);
8464         }
8465         spin_unlock(&root->delalloc_lock);
8466
8467         list_for_each_entry_safe(work, next, &works, list) {
8468                 list_del_init(&work->list);
8469                 btrfs_wait_and_free_delalloc_work(work);
8470         }
8471         return 0;
8472 out:
8473         list_for_each_entry_safe(work, next, &works, list) {
8474                 list_del_init(&work->list);
8475                 btrfs_wait_and_free_delalloc_work(work);
8476         }
8477
8478         if (!list_empty_careful(&splice)) {
8479                 spin_lock(&root->delalloc_lock);
8480                 list_splice_tail(&splice, &root->delalloc_inodes);
8481                 spin_unlock(&root->delalloc_lock);
8482         }
8483         return ret;
8484 }
8485
8486 int btrfs_start_delalloc_inodes(struct btrfs_root *root, int delay_iput)
8487 {
8488         int ret;
8489
8490         if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state))
8491                 return -EROFS;
8492
8493         ret = __start_delalloc_inodes(root, delay_iput);
8494         /*
8495          * the filemap_flush will queue IO into the worker threads, but
8496          * we have to make sure the IO is actually started and that
8497          * ordered extents get created before we return
8498          */
8499         atomic_inc(&root->fs_info->async_submit_draining);
8500         while (atomic_read(&root->fs_info->nr_async_submits) ||
8501               atomic_read(&root->fs_info->async_delalloc_pages)) {
8502                 wait_event(root->fs_info->async_submit_wait,
8503                    (atomic_read(&root->fs_info->nr_async_submits) == 0 &&
8504                     atomic_read(&root->fs_info->async_delalloc_pages) == 0));
8505         }
8506         atomic_dec(&root->fs_info->async_submit_draining);
8507         return ret;
8508 }
8509
8510 int btrfs_start_delalloc_roots(struct btrfs_fs_info *fs_info, int delay_iput)
8511 {
8512         struct btrfs_root *root;
8513         struct list_head splice;
8514         int ret;
8515
8516         if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state))
8517                 return -EROFS;
8518
8519         INIT_LIST_HEAD(&splice);
8520
8521         spin_lock(&fs_info->delalloc_root_lock);
8522         list_splice_init(&fs_info->delalloc_roots, &splice);
8523         while (!list_empty(&splice)) {
8524                 root = list_first_entry(&splice, struct btrfs_root,
8525                                         delalloc_root);
8526                 root = btrfs_grab_fs_root(root);
8527                 BUG_ON(!root);
8528                 list_move_tail(&root->delalloc_root,
8529                                &fs_info->delalloc_roots);
8530                 spin_unlock(&fs_info->delalloc_root_lock);
8531
8532                 ret = __start_delalloc_inodes(root, delay_iput);
8533                 btrfs_put_fs_root(root);
8534                 if (ret)
8535                         goto out;
8536
8537                 spin_lock(&fs_info->delalloc_root_lock);
8538         }
8539         spin_unlock(&fs_info->delalloc_root_lock);
8540
8541         atomic_inc(&fs_info->async_submit_draining);
8542         while (atomic_read(&fs_info->nr_async_submits) ||
8543               atomic_read(&fs_info->async_delalloc_pages)) {
8544                 wait_event(fs_info->async_submit_wait,
8545                    (atomic_read(&fs_info->nr_async_submits) == 0 &&
8546                     atomic_read(&fs_info->async_delalloc_pages) == 0));
8547         }
8548         atomic_dec(&fs_info->async_submit_draining);
8549         return 0;
8550 out:
8551         if (!list_empty_careful(&splice)) {
8552                 spin_lock(&fs_info->delalloc_root_lock);
8553                 list_splice_tail(&splice, &fs_info->delalloc_roots);
8554                 spin_unlock(&fs_info->delalloc_root_lock);
8555         }
8556         return ret;
8557 }
8558
8559 static int btrfs_symlink(struct inode *dir, struct dentry *dentry,
8560                          const char *symname)
8561 {
8562         struct btrfs_trans_handle *trans;
8563         struct btrfs_root *root = BTRFS_I(dir)->root;
8564         struct btrfs_path *path;
8565         struct btrfs_key key;
8566         struct inode *inode = NULL;
8567         int err;
8568         int drop_inode = 0;
8569         u64 objectid;
8570         u64 index = 0;
8571         int name_len;
8572         int datasize;
8573         unsigned long ptr;
8574         struct btrfs_file_extent_item *ei;
8575         struct extent_buffer *leaf;
8576
8577         name_len = strlen(symname);
8578         if (name_len > BTRFS_MAX_INLINE_DATA_SIZE(root))
8579                 return -ENAMETOOLONG;
8580
8581         /*
8582          * 2 items for inode item and ref
8583          * 2 items for dir items
8584          * 1 item for xattr if selinux is on
8585          */
8586         trans = btrfs_start_transaction(root, 5);
8587         if (IS_ERR(trans))
8588                 return PTR_ERR(trans);
8589
8590         err = btrfs_find_free_ino(root, &objectid);
8591         if (err)
8592                 goto out_unlock;
8593
8594         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
8595                                 dentry->d_name.len, btrfs_ino(dir), objectid,
8596                                 S_IFLNK|S_IRWXUGO, &index);
8597         if (IS_ERR(inode)) {
8598                 err = PTR_ERR(inode);
8599                 goto out_unlock;
8600         }
8601
8602         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
8603         if (err) {
8604                 drop_inode = 1;
8605                 goto out_unlock;
8606         }
8607
8608         /*
8609         * If the active LSM wants to access the inode during
8610         * d_instantiate it needs these. Smack checks to see
8611         * if the filesystem supports xattrs by looking at the
8612         * ops vector.
8613         */
8614         inode->i_fop = &btrfs_file_operations;
8615         inode->i_op = &btrfs_file_inode_operations;
8616
8617         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
8618         if (err)
8619                 drop_inode = 1;
8620         else {
8621                 inode->i_mapping->a_ops = &btrfs_aops;
8622                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
8623                 BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
8624         }
8625         if (drop_inode)
8626                 goto out_unlock;
8627
8628         path = btrfs_alloc_path();
8629         if (!path) {
8630                 err = -ENOMEM;
8631                 drop_inode = 1;
8632                 goto out_unlock;
8633         }
8634         key.objectid = btrfs_ino(inode);
8635         key.offset = 0;
8636         btrfs_set_key_type(&key, BTRFS_EXTENT_DATA_KEY);
8637         datasize = btrfs_file_extent_calc_inline_size(name_len);
8638         err = btrfs_insert_empty_item(trans, root, path, &key,
8639                                       datasize);
8640         if (err) {
8641                 drop_inode = 1;
8642                 btrfs_free_path(path);
8643                 goto out_unlock;
8644         }
8645         leaf = path->nodes[0];
8646         ei = btrfs_item_ptr(leaf, path->slots[0],
8647                             struct btrfs_file_extent_item);
8648         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
8649         btrfs_set_file_extent_type(leaf, ei,
8650                                    BTRFS_FILE_EXTENT_INLINE);
8651         btrfs_set_file_extent_encryption(leaf, ei, 0);
8652         btrfs_set_file_extent_compression(leaf, ei, 0);
8653         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
8654         btrfs_set_file_extent_ram_bytes(leaf, ei, name_len);
8655
8656         ptr = btrfs_file_extent_inline_start(ei);
8657         write_extent_buffer(leaf, symname, ptr, name_len);
8658         btrfs_mark_buffer_dirty(leaf);
8659         btrfs_free_path(path);
8660
8661         inode->i_op = &btrfs_symlink_inode_operations;
8662         inode->i_mapping->a_ops = &btrfs_symlink_aops;
8663         inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
8664         inode_set_bytes(inode, name_len);
8665         btrfs_i_size_write(inode, name_len);
8666         err = btrfs_update_inode(trans, root, inode);
8667         if (err)
8668                 drop_inode = 1;
8669
8670 out_unlock:
8671         if (!err)
8672                 d_instantiate(dentry, inode);
8673         btrfs_end_transaction(trans, root);
8674         if (drop_inode) {
8675                 inode_dec_link_count(inode);
8676                 iput(inode);
8677         }
8678         btrfs_btree_balance_dirty(root);
8679         return err;
8680 }
8681
8682 static int __btrfs_prealloc_file_range(struct inode *inode, int mode,
8683                                        u64 start, u64 num_bytes, u64 min_size,
8684                                        loff_t actual_len, u64 *alloc_hint,
8685                                        struct btrfs_trans_handle *trans)
8686 {
8687         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
8688         struct extent_map *em;
8689         struct btrfs_root *root = BTRFS_I(inode)->root;
8690         struct btrfs_key ins;
8691         u64 cur_offset = start;
8692         u64 i_size;
8693         u64 cur_bytes;
8694         int ret = 0;
8695         bool own_trans = true;
8696
8697         if (trans)
8698                 own_trans = false;
8699         while (num_bytes > 0) {
8700                 if (own_trans) {
8701                         trans = btrfs_start_transaction(root, 3);
8702                         if (IS_ERR(trans)) {
8703                                 ret = PTR_ERR(trans);
8704                                 break;
8705                         }
8706                 }
8707
8708                 cur_bytes = min(num_bytes, 256ULL * 1024 * 1024);
8709                 cur_bytes = max(cur_bytes, min_size);
8710                 ret = btrfs_reserve_extent(root, cur_bytes, min_size, 0,
8711                                            *alloc_hint, &ins, 1);
8712                 if (ret) {
8713                         if (own_trans)
8714                                 btrfs_end_transaction(trans, root);
8715                         break;
8716                 }
8717
8718                 ret = insert_reserved_file_extent(trans, inode,
8719                                                   cur_offset, ins.objectid,
8720                                                   ins.offset, ins.offset,
8721                                                   ins.offset, 0, 0, 0,
8722                                                   BTRFS_FILE_EXTENT_PREALLOC);
8723                 if (ret) {
8724                         btrfs_free_reserved_extent(root, ins.objectid,
8725                                                    ins.offset);
8726                         btrfs_abort_transaction(trans, root, ret);
8727                         if (own_trans)
8728                                 btrfs_end_transaction(trans, root);
8729                         break;
8730                 }
8731                 btrfs_drop_extent_cache(inode, cur_offset,
8732                                         cur_offset + ins.offset -1, 0);
8733
8734                 em = alloc_extent_map();
8735                 if (!em) {
8736                         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
8737                                 &BTRFS_I(inode)->runtime_flags);
8738                         goto next;
8739                 }
8740
8741                 em->start = cur_offset;
8742                 em->orig_start = cur_offset;
8743                 em->len = ins.offset;
8744                 em->block_start = ins.objectid;
8745                 em->block_len = ins.offset;
8746                 em->orig_block_len = ins.offset;
8747                 em->ram_bytes = ins.offset;
8748                 em->bdev = root->fs_info->fs_devices->latest_bdev;
8749                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
8750                 em->generation = trans->transid;
8751
8752                 while (1) {
8753                         write_lock(&em_tree->lock);
8754                         ret = add_extent_mapping(em_tree, em, 1);
8755                         write_unlock(&em_tree->lock);
8756                         if (ret != -EEXIST)
8757                                 break;
8758                         btrfs_drop_extent_cache(inode, cur_offset,
8759                                                 cur_offset + ins.offset - 1,
8760                                                 0);
8761                 }
8762                 free_extent_map(em);
8763 next:
8764                 num_bytes -= ins.offset;
8765                 cur_offset += ins.offset;
8766                 *alloc_hint = ins.objectid + ins.offset;
8767
8768                 inode_inc_iversion(inode);
8769                 inode->i_ctime = CURRENT_TIME;
8770                 BTRFS_I(inode)->flags |= BTRFS_INODE_PREALLOC;
8771                 if (!(mode & FALLOC_FL_KEEP_SIZE) &&
8772                     (actual_len > inode->i_size) &&
8773                     (cur_offset > inode->i_size)) {
8774                         if (cur_offset > actual_len)
8775                                 i_size = actual_len;
8776                         else
8777                                 i_size = cur_offset;
8778                         i_size_write(inode, i_size);
8779                         btrfs_ordered_update_i_size(inode, i_size, NULL);
8780                 }
8781
8782                 ret = btrfs_update_inode(trans, root, inode);
8783
8784                 if (ret) {
8785                         btrfs_abort_transaction(trans, root, ret);
8786                         if (own_trans)
8787                                 btrfs_end_transaction(trans, root);
8788                         break;
8789                 }
8790
8791                 if (own_trans)
8792                         btrfs_end_transaction(trans, root);
8793         }
8794         return ret;
8795 }
8796
8797 int btrfs_prealloc_file_range(struct inode *inode, int mode,
8798                               u64 start, u64 num_bytes, u64 min_size,
8799                               loff_t actual_len, u64 *alloc_hint)
8800 {
8801         return __btrfs_prealloc_file_range(inode, mode, start, num_bytes,
8802                                            min_size, actual_len, alloc_hint,
8803                                            NULL);
8804 }
8805
8806 int btrfs_prealloc_file_range_trans(struct inode *inode,
8807                                     struct btrfs_trans_handle *trans, int mode,
8808                                     u64 start, u64 num_bytes, u64 min_size,
8809                                     loff_t actual_len, u64 *alloc_hint)
8810 {
8811         return __btrfs_prealloc_file_range(inode, mode, start, num_bytes,
8812                                            min_size, actual_len, alloc_hint, trans);
8813 }
8814
8815 static int btrfs_set_page_dirty(struct page *page)
8816 {
8817         return __set_page_dirty_nobuffers(page);
8818 }
8819
8820 static int btrfs_permission(struct inode *inode, int mask)
8821 {
8822         struct btrfs_root *root = BTRFS_I(inode)->root;
8823         umode_t mode = inode->i_mode;
8824
8825         if (mask & MAY_WRITE &&
8826             (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode))) {
8827                 if (btrfs_root_readonly(root))
8828                         return -EROFS;
8829                 if (BTRFS_I(inode)->flags & BTRFS_INODE_READONLY)
8830                         return -EACCES;
8831         }
8832         return generic_permission(inode, mask);
8833 }
8834
8835 static const struct inode_operations btrfs_dir_inode_operations = {
8836         .getattr        = btrfs_getattr,
8837         .lookup         = btrfs_lookup,
8838         .create         = btrfs_create,
8839         .unlink         = btrfs_unlink,
8840         .link           = btrfs_link,
8841         .mkdir          = btrfs_mkdir,
8842         .rmdir          = btrfs_rmdir,
8843         .rename         = btrfs_rename,
8844         .symlink        = btrfs_symlink,
8845         .setattr        = btrfs_setattr,
8846         .mknod          = btrfs_mknod,
8847         .setxattr       = btrfs_setxattr,
8848         .getxattr       = btrfs_getxattr,
8849         .listxattr      = btrfs_listxattr,
8850         .removexattr    = btrfs_removexattr,
8851         .permission     = btrfs_permission,
8852         .get_acl        = btrfs_get_acl,
8853         .set_acl        = btrfs_set_acl,
8854         .update_time    = btrfs_update_time,
8855 };
8856 static const struct inode_operations btrfs_dir_ro_inode_operations = {
8857         .lookup         = btrfs_lookup,
8858         .permission     = btrfs_permission,
8859         .get_acl        = btrfs_get_acl,
8860         .set_acl        = btrfs_set_acl,
8861         .update_time    = btrfs_update_time,
8862 };
8863
8864 static const struct file_operations btrfs_dir_file_operations = {
8865         .llseek         = generic_file_llseek,
8866         .read           = generic_read_dir,
8867         .iterate        = btrfs_real_readdir,
8868         .unlocked_ioctl = btrfs_ioctl,
8869 #ifdef CONFIG_COMPAT
8870         .compat_ioctl   = btrfs_ioctl,
8871 #endif
8872         .release        = btrfs_release_file,
8873         .fsync          = btrfs_sync_file,
8874 };
8875
8876 static struct extent_io_ops btrfs_extent_io_ops = {
8877         .fill_delalloc = run_delalloc_range,
8878         .submit_bio_hook = btrfs_submit_bio_hook,
8879         .merge_bio_hook = btrfs_merge_bio_hook,
8880         .readpage_end_io_hook = btrfs_readpage_end_io_hook,
8881         .writepage_end_io_hook = btrfs_writepage_end_io_hook,
8882         .writepage_start_hook = btrfs_writepage_start_hook,
8883         .set_bit_hook = btrfs_set_bit_hook,
8884         .clear_bit_hook = btrfs_clear_bit_hook,
8885         .merge_extent_hook = btrfs_merge_extent_hook,
8886         .split_extent_hook = btrfs_split_extent_hook,
8887 };
8888
8889 /*
8890  * btrfs doesn't support the bmap operation because swapfiles
8891  * use bmap to make a mapping of extents in the file.  They assume
8892  * these extents won't change over the life of the file and they
8893  * use the bmap result to do IO directly to the drive.
8894  *
8895  * the btrfs bmap call would return logical addresses that aren't
8896  * suitable for IO and they also will change frequently as COW
8897  * operations happen.  So, swapfile + btrfs == corruption.
8898  *
8899  * For now we're avoiding this by dropping bmap.
8900  */
8901 static const struct address_space_operations btrfs_aops = {
8902         .readpage       = btrfs_readpage,
8903         .writepage      = btrfs_writepage,
8904         .writepages     = btrfs_writepages,
8905         .readpages      = btrfs_readpages,
8906         .direct_IO      = btrfs_direct_IO,
8907         .invalidatepage = btrfs_invalidatepage,
8908         .releasepage    = btrfs_releasepage,
8909         .set_page_dirty = btrfs_set_page_dirty,
8910         .error_remove_page = generic_error_remove_page,
8911 };
8912
8913 static const struct address_space_operations btrfs_symlink_aops = {
8914         .readpage       = btrfs_readpage,
8915         .writepage      = btrfs_writepage,
8916         .invalidatepage = btrfs_invalidatepage,
8917         .releasepage    = btrfs_releasepage,
8918 };
8919
8920 static const struct inode_operations btrfs_file_inode_operations = {
8921         .getattr        = btrfs_getattr,
8922         .setattr        = btrfs_setattr,
8923         .setxattr       = btrfs_setxattr,
8924         .getxattr       = btrfs_getxattr,
8925         .listxattr      = btrfs_listxattr,
8926         .removexattr    = btrfs_removexattr,
8927         .permission     = btrfs_permission,
8928         .fiemap         = btrfs_fiemap,
8929         .get_acl        = btrfs_get_acl,
8930         .set_acl        = btrfs_set_acl,
8931         .update_time    = btrfs_update_time,
8932 };
8933 static const struct inode_operations btrfs_special_inode_operations = {
8934         .getattr        = btrfs_getattr,
8935         .setattr        = btrfs_setattr,
8936         .permission     = btrfs_permission,
8937         .setxattr       = btrfs_setxattr,
8938         .getxattr       = btrfs_getxattr,
8939         .listxattr      = btrfs_listxattr,
8940         .removexattr    = btrfs_removexattr,
8941         .get_acl        = btrfs_get_acl,
8942         .set_acl        = btrfs_set_acl,
8943         .update_time    = btrfs_update_time,
8944 };
8945 static const struct inode_operations btrfs_symlink_inode_operations = {
8946         .readlink       = generic_readlink,
8947         .follow_link    = page_follow_link_light,
8948         .put_link       = page_put_link,
8949         .getattr        = btrfs_getattr,
8950         .setattr        = btrfs_setattr,
8951         .permission     = btrfs_permission,
8952         .setxattr       = btrfs_setxattr,
8953         .getxattr       = btrfs_getxattr,
8954         .listxattr      = btrfs_listxattr,
8955         .removexattr    = btrfs_removexattr,
8956         .update_time    = btrfs_update_time,
8957 };
8958
8959 const struct dentry_operations btrfs_dentry_operations = {
8960         .d_delete       = btrfs_dentry_delete,
8961         .d_release      = btrfs_dentry_release,
8962 };