Pileus Git - ~andy/linux/blob - fs/btrfs/disk-io.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/version.h>
  20 #include <linux/fs.h>
  21 #include <linux/blkdev.h>
  22 #include <linux/scatterlist.h>
  23 #include <linux/swap.h>
  24 #include <linux/radix-tree.h>
  25 #include <linux/writeback.h>
  26 #include <linux/buffer_head.h> // for block_sync_page
  27 #include <linux/workqueue.h>
  28 #include <linux/kthread.h>
  29 # include <linux/freezer.h>
  30 #include "crc32c.h"
  31 #include "ctree.h"
  32 #include "disk-io.h"
  33 #include "transaction.h"
  34 #include "btrfs_inode.h"
  35 #include "volumes.h"
  36 #include "print-tree.h"
  37 #include "async-thread.h"
  38 #include "locking.h"
  39 #include "ref-cache.h"
  40 #include "tree-log.h"
  41
  42 #if 0
  43 static int check_tree_block(struct btrfs_root *root, struct extent_buffer *buf)
  44 {
  45         if (extent_buffer_blocknr(buf) != btrfs_header_blocknr(buf)) {
  46                 printk(KERN_CRIT "buf blocknr(buf) is %llu, header is %llu\n",
  47                        (unsigned long long)extent_buffer_blocknr(buf),
  48                        (unsigned long long)btrfs_header_blocknr(buf));
  49                 return 1;
  50         }
  51         return 0;
  52 }
  53 #endif
  54
  55 static struct extent_io_ops btree_extent_io_ops;
  56 static void end_workqueue_fn(struct btrfs_work *work);
  57
  58 /*
  59  * end_io_wq structs are used to do processing in task context when an IO is
  60  * complete.  This is used during reads to verify checksums, and it is used
  61  * by writes to insert metadata for new file extents after IO is complete.
  62  */
  63 struct end_io_wq {
  64         struct bio *bio;
  65         bio_end_io_t *end_io;
  66         void *private;
  67         struct btrfs_fs_info *info;
  68         int error;
  69         int metadata;
  70         struct list_head list;
  71         struct btrfs_work work;
  72 };
  73
  74 /*
  75  * async submit bios are used to offload expensive checksumming
  76  * onto the worker threads.  They checksum file and metadata bios
  77  * just before they are sent down the IO stack.
  78  */
  79 struct async_submit_bio {
  80         struct inode *inode;
  81         struct bio *bio;
  82         struct list_head list;
  83         extent_submit_bio_hook_t *submit_bio_hook;
  84         int rw;
  85         int mirror_num;
  86         unsigned long bio_flags;
  87         struct btrfs_work work;
  88 };
  89
  90 /*
  91  * extents on the btree inode are pretty simple, there's one extent
  92  * that covers the entire device
  93  */
  94 struct extent_map *btree_get_extent(struct inode *inode, struct page *page,
  95                                     size_t page_offset, u64 start, u64 len,
  96                                     int create)
  97 {
  98         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
  99         struct extent_map *em;
 100         int ret;
 101
 102         spin_lock(&em_tree->lock);
 103         em = lookup_extent_mapping(em_tree, start, len);
 104         if (em) {
 105                 em->bdev =
 106                         BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
 107                 spin_unlock(&em_tree->lock);
 108                 goto out;
 109         }
 110         spin_unlock(&em_tree->lock);
 111
 112         em = alloc_extent_map(GFP_NOFS);
 113         if (!em) {
 114                 em = ERR_PTR(-ENOMEM);
 115                 goto out;
 116         }
 117         em->start = 0;
 118         em->len = (u64)-1;
 119         em->block_len = (u64)-1;
 120         em->block_start = 0;
 121         em->bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
 122
 123         spin_lock(&em_tree->lock);
 124         ret = add_extent_mapping(em_tree, em);
 125         if (ret == -EEXIST) {
 126                 u64 failed_start = em->start;
 127                 u64 failed_len = em->len;
 128
 129                 printk("failed to insert %Lu %Lu -> %Lu into tree\n",
 130                        em->start, em->len, em->block_start);
 131                 free_extent_map(em);
 132                 em = lookup_extent_mapping(em_tree, start, len);
 133                 if (em) {
 134                         printk("after failing, found %Lu %Lu %Lu\n",
 135                                em->start, em->len, em->block_start);
 136                         ret = 0;
 137                 } else {
 138                         em = lookup_extent_mapping(em_tree, failed_start,
 139                                                    failed_len);
 140                         if (em) {
 141                                 printk("double failure lookup gives us "
 142                                        "%Lu %Lu -> %Lu\n", em->start,
 143                                        em->len, em->block_start);
 144                                 free_extent_map(em);
 145                         }
 146                         ret = -EIO;
 147                 }
 148         } else if (ret) {
 149                 free_extent_map(em);
 150                 em = NULL;
 151         }
 152         spin_unlock(&em_tree->lock);
 153
 154         if (ret)
 155                 em = ERR_PTR(ret);
 156 out:
 157         return em;
 158 }
 159
 160 u32 btrfs_csum_data(struct btrfs_root *root, char *data, u32 seed, size_t len)
 161 {
 162         return btrfs_crc32c(seed, data, len);
 163 }
 164
 165 void btrfs_csum_final(u32 crc, char *result)
 166 {
 167         *(__le32 *)result = ~cpu_to_le32(crc);
 168 }
 169
 170 /*
 171  * compute the csum for a btree block, and either verify it or write it
 172  * into the csum field of the block.
 173  */
 174 static int csum_tree_block(struct btrfs_root *root, struct extent_buffer *buf,
 175                            int verify)
 176 {
 177         char result[BTRFS_CRC32_SIZE];
 178         unsigned long len;
 179         unsigned long cur_len;
 180         unsigned long offset = BTRFS_CSUM_SIZE;
 181         char *map_token = NULL;
 182         char *kaddr;
 183         unsigned long map_start;
 184         unsigned long map_len;
 185         int err;
 186         u32 crc = ~(u32)0;
 187
 188         len = buf->len - offset;
 189         while(len > 0) {
 190                 err = map_private_extent_buffer(buf, offset, 32,
 191                                         &map_token, &kaddr,
 192                                         &map_start, &map_len, KM_USER0);
 193                 if (err) {
 194                         printk("failed to map extent buffer! %lu\n",
 195                                offset);
 196                         return 1;
 197                 }
 198                 cur_len = min(len, map_len - (offset - map_start));
 199                 crc = btrfs_csum_data(root, kaddr + offset - map_start,
 200                                       crc, cur_len);
 201                 len -= cur_len;
 202                 offset += cur_len;
 203                 unmap_extent_buffer(buf, map_token, KM_USER0);
 204         }
 205         btrfs_csum_final(crc, result);
 206
 207         if (verify) {
 208                 /* FIXME, this is not good */
 209                 if (memcmp_extent_buffer(buf, result, 0, BTRFS_CRC32_SIZE)) {
 210                         u32 val;
 211                         u32 found = 0;
 212                         memcpy(&found, result, BTRFS_CRC32_SIZE);
 213
 214                         read_extent_buffer(buf, &val, 0, BTRFS_CRC32_SIZE);
 215                         printk("btrfs: %s checksum verify failed on %llu "
 216                                "wanted %X found %X level %d\n",
 217                                root->fs_info->sb->s_id,
 218                                buf->start, val, found, btrfs_header_level(buf));
 219                         return 1;
 220                 }
 221         } else {
 222                 write_extent_buffer(buf, result, 0, BTRFS_CRC32_SIZE);
 223         }
 224         return 0;
 225 }
 226
 227 /*
 228  * we can't consider a given block up to date unless the transid of the
 229  * block matches the transid in the parent node's pointer.  This is how we
 230  * detect blocks that either didn't get written at all or got written
 231  * in the wrong place.
 232  */
 233 static int verify_parent_transid(struct extent_io_tree *io_tree,
 234                                  struct extent_buffer *eb, u64 parent_transid)
 235 {
 236         int ret;
 237
 238         if (!parent_transid || btrfs_header_generation(eb) == parent_transid)
 239                 return 0;
 240
 241         lock_extent(io_tree, eb->start, eb->start + eb->len - 1, GFP_NOFS);
 242         if (extent_buffer_uptodate(io_tree, eb) &&
 243             btrfs_header_generation(eb) == parent_transid) {
 244                 ret = 0;
 245                 goto out;
 246         }
 247         printk("parent transid verify failed on %llu wanted %llu found %llu\n",
 248                (unsigned long long)eb->start,
 249                (unsigned long long)parent_transid,
 250                (unsigned long long)btrfs_header_generation(eb));
 251         ret = 1;
 252         clear_extent_buffer_uptodate(io_tree, eb);
 253 out:
 254         unlock_extent(io_tree, eb->start, eb->start + eb->len - 1,
 255                       GFP_NOFS);
 256         return ret;
 257 }
 258
 259 /*
 260  * helper to read a given tree block, doing retries as required when
 261  * the checksums don't match and we have alternate mirrors to try.
 262  */
 263 static int btree_read_extent_buffer_pages(struct btrfs_root *root,
 264                                           struct extent_buffer *eb,
 265                                           u64 start, u64 parent_transid)
 266 {
 267         struct extent_io_tree *io_tree;
 268         int ret;
 269         int num_copies = 0;
 270         int mirror_num = 0;
 271
 272         io_tree = &BTRFS_I(root->fs_info->btree_inode)->io_tree;
 273         while (1) {
 274                 ret = read_extent_buffer_pages(io_tree, eb, start, 1,
 275                                                btree_get_extent, mirror_num);
 276                 if (!ret &&
 277                     !verify_parent_transid(io_tree, eb, parent_transid))
 278                         return ret;
 279 printk("read extent buffer pages failed with ret %d mirror no %d\n", ret, mirror_num);
 280                 num_copies = btrfs_num_copies(&root->fs_info->mapping_tree,
 281                                               eb->start, eb->len);
 282                 if (num_copies == 1)
 283                         return ret;
 284
 285                 mirror_num++;
 286                 if (mirror_num > num_copies)
 287                         return ret;
 288         }
 289         return -EIO;
 290 }
 291
 292 /*
 293  * checksum a dirty tree block before IO.  This has extra checks to make
 294  * sure we only fill in the checksum field in the first page of a multi-page block
 295  */
 296 int csum_dirty_buffer(struct btrfs_root *root, struct page *page)
 297 {
 298         struct extent_io_tree *tree;
 299         u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
 300         u64 found_start;
 301         int found_level;
 302         unsigned long len;
 303         struct extent_buffer *eb;
 304         int ret;
 305
 306         tree = &BTRFS_I(page->mapping->host)->io_tree;
 307
 308         if (page->private == EXTENT_PAGE_PRIVATE)
 309                 goto out;
 310         if (!page->private)
 311                 goto out;
 312         len = page->private >> 2;
 313         if (len == 0) {
 314                 WARN_ON(1);
 315         }
 316         eb = alloc_extent_buffer(tree, start, len, page, GFP_NOFS);
 317         ret = btree_read_extent_buffer_pages(root, eb, start + PAGE_CACHE_SIZE,
 318                                              btrfs_header_generation(eb));
 319         BUG_ON(ret);
 320         found_start = btrfs_header_bytenr(eb);
 321         if (found_start != start) {
 322                 printk("warning: eb start incorrect %Lu buffer %Lu len %lu\n",
 323                        start, found_start, len);
 324                 WARN_ON(1);
 325                 goto err;
 326         }
 327         if (eb->first_page != page) {
 328                 printk("bad first page %lu %lu\n", eb->first_page->index,
 329                        page->index);
 330                 WARN_ON(1);
 331                 goto err;
 332         }
 333         if (!PageUptodate(page)) {
 334                 printk("csum not up to date page %lu\n", page->index);
 335                 WARN_ON(1);
 336                 goto err;
 337         }
 338         found_level = btrfs_header_level(eb);
 339
 340         csum_tree_block(root, eb, 0);
 341 err:
 342         free_extent_buffer(eb);
 343 out:
 344         return 0;
 345 }
 346
 347 int btree_readpage_end_io_hook(struct page *page, u64 start, u64 end,
 348                                struct extent_state *state)
 349 {
 350         struct extent_io_tree *tree;
 351         u64 found_start;
 352         int found_level;
 353         unsigned long len;
 354         struct extent_buffer *eb;
 355         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
 356         int ret = 0;
 357
 358         tree = &BTRFS_I(page->mapping->host)->io_tree;
 359         if (page->private == EXTENT_PAGE_PRIVATE)
 360                 goto out;
 361         if (!page->private)
 362                 goto out;
 363         len = page->private >> 2;
 364         if (len == 0) {
 365                 WARN_ON(1);
 366         }
 367         eb = alloc_extent_buffer(tree, start, len, page, GFP_NOFS);
 368
 369         found_start = btrfs_header_bytenr(eb);
 370         if (found_start != start) {
 371                 printk("bad tree block start %llu %llu\n",
 372                        (unsigned long long)found_start,
 373                        (unsigned long long)eb->start);
 374                 ret = -EIO;
 375                 goto err;
 376         }
 377         if (eb->first_page != page) {
 378                 printk("bad first page %lu %lu\n", eb->first_page->index,
 379                        page->index);
 380                 WARN_ON(1);
 381                 ret = -EIO;
 382                 goto err;
 383         }
 384         if (memcmp_extent_buffer(eb, root->fs_info->fsid,
 385                                  (unsigned long)btrfs_header_fsid(eb),
 386                                  BTRFS_FSID_SIZE)) {
 387                 printk("bad fsid on block %Lu\n", eb->start);
 388                 ret = -EIO;
 389                 goto err;
 390         }
 391         found_level = btrfs_header_level(eb);
 392
 393         ret = csum_tree_block(root, eb, 1);
 394         if (ret)
 395                 ret = -EIO;
 396
 397         end = min_t(u64, eb->len, PAGE_CACHE_SIZE);
 398         end = eb->start + end - 1;
 399 err:
 400         free_extent_buffer(eb);
 401 out:
 402         return ret;
 403 }
 404
 405 static void end_workqueue_bio(struct bio *bio, int err)
 406 {
 407         struct end_io_wq *end_io_wq = bio->bi_private;
 408         struct btrfs_fs_info *fs_info;
 409
 410         fs_info = end_io_wq->info;
 411         end_io_wq->error = err;
 412         end_io_wq->work.func = end_workqueue_fn;
 413         end_io_wq->work.flags = 0;
 414         if (bio->bi_rw & (1 << BIO_RW))
 415                 btrfs_queue_worker(&fs_info->endio_write_workers,
 416                                    &end_io_wq->work);
 417         else
 418                 btrfs_queue_worker(&fs_info->endio_workers, &end_io_wq->work);
 419 }
 420
 421 int btrfs_bio_wq_end_io(struct btrfs_fs_info *info, struct bio *bio,
 422                         int metadata)
 423 {
 424         struct end_io_wq *end_io_wq;
 425         end_io_wq = kmalloc(sizeof(*end_io_wq), GFP_NOFS);
 426         if (!end_io_wq)
 427                 return -ENOMEM;
 428
 429         end_io_wq->private = bio->bi_private;
 430         end_io_wq->end_io = bio->bi_end_io;
 431         end_io_wq->info = info;
 432         end_io_wq->error = 0;
 433         end_io_wq->bio = bio;
 434         end_io_wq->metadata = metadata;
 435
 436         bio->bi_private = end_io_wq;
 437         bio->bi_end_io = end_workqueue_bio;
 438         return 0;
 439 }
 440
 441 unsigned long btrfs_async_submit_limit(struct btrfs_fs_info *info)
 442 {
 443         unsigned long limit = min_t(unsigned long,
 444                                     info->workers.max_workers,
 445                                     info->fs_devices->open_devices);
 446         return 256 * limit;
 447 }
 448
 449 int btrfs_congested_async(struct btrfs_fs_info *info, int iodone)
 450 {
 451         return atomic_read(&info->nr_async_bios) >
 452                 btrfs_async_submit_limit(info);
 453 }
 454
 455 static void run_one_async_submit(struct btrfs_work *work)
 456 {
 457         struct btrfs_fs_info *fs_info;
 458         struct async_submit_bio *async;
 459         int limit;
 460
 461         async = container_of(work, struct  async_submit_bio, work);
 462         fs_info = BTRFS_I(async->inode)->root->fs_info;
 463
 464         limit = btrfs_async_submit_limit(fs_info);
 465         limit = limit * 2 / 3;
 466
 467         atomic_dec(&fs_info->nr_async_submits);
 468
 469         if (atomic_read(&fs_info->nr_async_submits) < limit &&
 470             waitqueue_active(&fs_info->async_submit_wait))
 471                 wake_up(&fs_info->async_submit_wait);
 472
 473         async->submit_bio_hook(async->inode, async->rw, async->bio,
 474                                async->mirror_num, async->bio_flags);
 475         kfree(async);
 476 }
 477
 478 int btrfs_wq_submit_bio(struct btrfs_fs_info *fs_info, struct inode *inode,
 479                         int rw, struct bio *bio, int mirror_num,
 480                         unsigned long bio_flags,
 481                         extent_submit_bio_hook_t *submit_bio_hook)
 482 {
 483         struct async_submit_bio *async;
 484         int limit = btrfs_async_submit_limit(fs_info);
 485
 486         async = kmalloc(sizeof(*async), GFP_NOFS);
 487         if (!async)
 488                 return -ENOMEM;
 489
 490         async->inode = inode;
 491         async->rw = rw;
 492         async->bio = bio;
 493         async->mirror_num = mirror_num;
 494         async->submit_bio_hook = submit_bio_hook;
 495         async->work.func = run_one_async_submit;
 496         async->work.flags = 0;
 497         async->bio_flags = bio_flags;
 498
 499         while(atomic_read(&fs_info->async_submit_draining) &&
 500               atomic_read(&fs_info->nr_async_submits)) {
 501                 wait_event(fs_info->async_submit_wait,
 502                            (atomic_read(&fs_info->nr_async_submits) == 0));
 503         }
 504
 505         atomic_inc(&fs_info->nr_async_submits);
 506         btrfs_queue_worker(&fs_info->workers, &async->work);
 507
 508         if (atomic_read(&fs_info->nr_async_submits) > limit) {
 509                 wait_event_timeout(fs_info->async_submit_wait,
 510                            (atomic_read(&fs_info->nr_async_submits) < limit),
 511                            HZ/10);
 512
 513                 wait_event_timeout(fs_info->async_submit_wait,
 514                            (atomic_read(&fs_info->nr_async_bios) < limit),
 515                            HZ/10);
 516         }
 517         return 0;
 518 }
 519
 520 static int btree_csum_one_bio(struct bio *bio)
 521 {
 522         struct bio_vec *bvec = bio->bi_io_vec;
 523         int bio_index = 0;
 524         struct btrfs_root *root;
 525
 526         WARN_ON(bio->bi_vcnt <= 0);
 527         while(bio_index < bio->bi_vcnt) {
 528                 root = BTRFS_I(bvec->bv_page->mapping->host)->root;
 529                 csum_dirty_buffer(root, bvec->bv_page);
 530                 bio_index++;
 531                 bvec++;
 532         }
 533         return 0;
 534 }
 535
 536 static int __btree_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
 537                                  int mirror_num, unsigned long bio_flags)
 538 {
 539         struct btrfs_root *root = BTRFS_I(inode)->root;
 540         int ret;
 541
 542         /*
 543          * when we're called for a write, we're already in the async
 544          * submission context.  Just jump into btrfs_map_bio
 545          */
 546         if (rw & (1 << BIO_RW)) {
 547                 btree_csum_one_bio(bio);
 548                 return btrfs_map_bio(BTRFS_I(inode)->root, rw, bio,
 549                                      mirror_num, 1);
 550         }
 551
 552         /*
 553          * called for a read, do the setup so that checksum validation
 554          * can happen in the async kernel threads
 555          */
 556         ret = btrfs_bio_wq_end_io(root->fs_info, bio, 1);
 557         BUG_ON(ret);
 558
 559         return btrfs_map_bio(BTRFS_I(inode)->root, rw, bio, mirror_num, 1);
 560 }
 561
 562 static int btree_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
 563                                  int mirror_num, unsigned long bio_flags)
 564 {
 565         /*
 566          * kthread helpers are used to submit writes so that checksumming
 567          * can happen in parallel across all CPUs
 568          */
 569         if (!(rw & (1 << BIO_RW))) {
 570                 return __btree_submit_bio_hook(inode, rw, bio, mirror_num, 0);
 571         }
 572         return btrfs_wq_submit_bio(BTRFS_I(inode)->root->fs_info,
 573                                    inode, rw, bio, mirror_num, 0,
 574                                    __btree_submit_bio_hook);
 575 }
 576
 577 static int btree_writepage(struct page *page, struct writeback_control *wbc)
 578 {
 579         struct extent_io_tree *tree;
 580         tree = &BTRFS_I(page->mapping->host)->io_tree;
 581
 582         if (current->flags & PF_MEMALLOC) {
 583                 redirty_page_for_writepage(wbc, page);
 584                 unlock_page(page);
 585                 return 0;
 586         }
 587         return extent_write_full_page(tree, page, btree_get_extent, wbc);
 588 }
 589
 590 static int btree_writepages(struct address_space *mapping,
 591                             struct writeback_control *wbc)
 592 {
 593         struct extent_io_tree *tree;
 594         tree = &BTRFS_I(mapping->host)->io_tree;
 595         if (wbc->sync_mode == WB_SYNC_NONE) {
 596                 u64 num_dirty;
 597                 u64 start = 0;
 598                 unsigned long thresh = 32 * 1024 * 1024;
 599
 600                 if (wbc->for_kupdate)
 601                         return 0;
 602
 603                 num_dirty = count_range_bits(tree, &start, (u64)-1,
 604                                              thresh, EXTENT_DIRTY);
 605                 if (num_dirty < thresh) {
 606                         return 0;
 607                 }
 608         }
 609         return extent_writepages(tree, mapping, btree_get_extent, wbc);
 610 }
 611
 612 int btree_readpage(struct file *file, struct page *page)
 613 {
 614         struct extent_io_tree *tree;
 615         tree = &BTRFS_I(page->mapping->host)->io_tree;
 616         return extent_read_full_page(tree, page, btree_get_extent);
 617 }
 618
 619 static int btree_releasepage(struct page *page, gfp_t gfp_flags)
 620 {
 621         struct extent_io_tree *tree;
 622         struct extent_map_tree *map;
 623         int ret;
 624
 625         if (PageWriteback(page) || PageDirty(page))
 626             return 0;
 627
 628         tree = &BTRFS_I(page->mapping->host)->io_tree;
 629         map = &BTRFS_I(page->mapping->host)->extent_tree;
 630
 631         ret = try_release_extent_state(map, tree, page, gfp_flags);
 632         if (!ret) {
 633                 return 0;
 634         }
 635
 636         ret = try_release_extent_buffer(tree, page);
 637         if (ret == 1) {
 638                 ClearPagePrivate(page);
 639                 set_page_private(page, 0);
 640                 page_cache_release(page);
 641         }
 642
 643         return ret;
 644 }
 645
 646 static void btree_invalidatepage(struct page *page, unsigned long offset)
 647 {
 648         struct extent_io_tree *tree;
 649         tree = &BTRFS_I(page->mapping->host)->io_tree;
 650         extent_invalidatepage(tree, page, offset);
 651         btree_releasepage(page, GFP_NOFS);
 652         if (PagePrivate(page)) {
 653                 printk("warning page private not zero on page %Lu\n",
 654                        page_offset(page));
 655                 ClearPagePrivate(page);
 656                 set_page_private(page, 0);
 657                 page_cache_release(page);
 658         }
 659 }
 660
 661 #if 0
 662 static int btree_writepage(struct page *page, struct writeback_control *wbc)
 663 {
 664         struct buffer_head *bh;
 665         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
 666         struct buffer_head *head;
 667         if (!page_has_buffers(page)) {
 668                 create_empty_buffers(page, root->fs_info->sb->s_blocksize,
 669                                         (1 << BH_Dirty)|(1 << BH_Uptodate));
 670         }
 671         head = page_buffers(page);
 672         bh = head;
 673         do {
 674                 if (buffer_dirty(bh))
 675                         csum_tree_block(root, bh, 0);
 676                 bh = bh->b_this_page;
 677         } while (bh != head);
 678         return block_write_full_page(page, btree_get_block, wbc);
 679 }
 680 #endif
 681
 682 static struct address_space_operations btree_aops = {
 683         .readpage       = btree_readpage,
 684         .writepage      = btree_writepage,
 685         .writepages     = btree_writepages,
 686         .releasepage    = btree_releasepage,
 687         .invalidatepage = btree_invalidatepage,
 688         .sync_page      = block_sync_page,
 689 };
 690
 691 int readahead_tree_block(struct btrfs_root *root, u64 bytenr, u32 blocksize,
 692                          u64 parent_transid)
 693 {
 694         struct extent_buffer *buf = NULL;
 695         struct inode *btree_inode = root->fs_info->btree_inode;
 696         int ret = 0;
 697
 698         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
 699         if (!buf)
 700                 return 0;
 701         read_extent_buffer_pages(&BTRFS_I(btree_inode)->io_tree,
 702                                  buf, 0, 0, btree_get_extent, 0);
 703         free_extent_buffer(buf);
 704         return ret;
 705 }
 706
 707 struct extent_buffer *btrfs_find_tree_block(struct btrfs_root *root,
 708                                             u64 bytenr, u32 blocksize)
 709 {
 710         struct inode *btree_inode = root->fs_info->btree_inode;
 711         struct extent_buffer *eb;
 712         eb = find_extent_buffer(&BTRFS_I(btree_inode)->io_tree,
 713                                 bytenr, blocksize, GFP_NOFS);
 714         return eb;
 715 }
 716
 717 struct extent_buffer *btrfs_find_create_tree_block(struct btrfs_root *root,
 718                                                  u64 bytenr, u32 blocksize)
 719 {
 720         struct inode *btree_inode = root->fs_info->btree_inode;
 721         struct extent_buffer *eb;
 722
 723         eb = alloc_extent_buffer(&BTRFS_I(btree_inode)->io_tree,
 724                                  bytenr, blocksize, NULL, GFP_NOFS);
 725         return eb;
 726 }
 727
 728
 729 int btrfs_write_tree_block(struct extent_buffer *buf)
 730 {
 731         return btrfs_fdatawrite_range(buf->first_page->mapping, buf->start,
 732                                       buf->start + buf->len - 1, WB_SYNC_ALL);
 733 }
 734
 735 int btrfs_wait_tree_block_writeback(struct extent_buffer *buf)
 736 {
 737         return btrfs_wait_on_page_writeback_range(buf->first_page->mapping,
 738                                   buf->start, buf->start + buf->len -1);
 739 }
 740
 741 struct extent_buffer *read_tree_block(struct btrfs_root *root, u64 bytenr,
 742                                       u32 blocksize, u64 parent_transid)
 743 {
 744         struct extent_buffer *buf = NULL;
 745         struct inode *btree_inode = root->fs_info->btree_inode;
 746         struct extent_io_tree *io_tree;
 747         int ret;
 748
 749         io_tree = &BTRFS_I(btree_inode)->io_tree;
 750
 751         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
 752         if (!buf)
 753                 return NULL;
 754
 755         ret = btree_read_extent_buffer_pages(root, buf, 0, parent_transid);
 756
 757         if (ret == 0) {
 758                 buf->flags |= EXTENT_UPTODATE;
 759         } else {
 760                 WARN_ON(1);
 761         }
 762         return buf;
 763
 764 }
 765
 766 int clean_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 767                      struct extent_buffer *buf)
 768 {
 769         struct inode *btree_inode = root->fs_info->btree_inode;
 770         if (btrfs_header_generation(buf) ==
 771             root->fs_info->running_transaction->transid) {
 772                 WARN_ON(!btrfs_tree_locked(buf));
 773                 clear_extent_buffer_dirty(&BTRFS_I(btree_inode)->io_tree,
 774                                           buf);
 775         }
 776         return 0;
 777 }
 778
 779 static int __setup_root(u32 nodesize, u32 leafsize, u32 sectorsize,
 780                         u32 stripesize, struct btrfs_root *root,
 781                         struct btrfs_fs_info *fs_info,
 782                         u64 objectid)
 783 {
 784         root->node = NULL;
 785         root->inode = NULL;
 786         root->commit_root = NULL;
 787         root->ref_tree = NULL;
 788         root->sectorsize = sectorsize;
 789         root->nodesize = nodesize;
 790         root->leafsize = leafsize;
 791         root->stripesize = stripesize;
 792         root->ref_cows = 0;
 793         root->track_dirty = 0;
 794
 795         root->fs_info = fs_info;
 796         root->objectid = objectid;
 797         root->last_trans = 0;
 798         root->highest_inode = 0;
 799         root->last_inode_alloc = 0;
 800         root->name = NULL;
 801         root->in_sysfs = 0;
 802
 803         INIT_LIST_HEAD(&root->dirty_list);
 804         INIT_LIST_HEAD(&root->orphan_list);
 805         INIT_LIST_HEAD(&root->dead_list);
 806         spin_lock_init(&root->node_lock);
 807         spin_lock_init(&root->list_lock);
 808         mutex_init(&root->objectid_mutex);
 809         mutex_init(&root->log_mutex);
 810         extent_io_tree_init(&root->dirty_log_pages,
 811                              fs_info->btree_inode->i_mapping, GFP_NOFS);
 812
 813         btrfs_leaf_ref_tree_init(&root->ref_tree_struct);
 814         root->ref_tree = &root->ref_tree_struct;
 815
 816         memset(&root->root_key, 0, sizeof(root->root_key));
 817         memset(&root->root_item, 0, sizeof(root->root_item));
 818         memset(&root->defrag_progress, 0, sizeof(root->defrag_progress));
 819         memset(&root->root_kobj, 0, sizeof(root->root_kobj));
 820         root->defrag_trans_start = fs_info->generation;
 821         init_completion(&root->kobj_unregister);
 822         root->defrag_running = 0;
 823         root->defrag_level = 0;
 824         root->root_key.objectid = objectid;
 825         return 0;
 826 }
 827
 828 static int find_and_setup_root(struct btrfs_root *tree_root,
 829                                struct btrfs_fs_info *fs_info,
 830                                u64 objectid,
 831                                struct btrfs_root *root)
 832 {
 833         int ret;
 834         u32 blocksize;
 835         u64 generation;
 836
 837         __setup_root(tree_root->nodesize, tree_root->leafsize,
 838                      tree_root->sectorsize, tree_root->stripesize,
 839                      root, fs_info, objectid);
 840         ret = btrfs_find_last_root(tree_root, objectid,
 841                                    &root->root_item, &root->root_key);
 842         BUG_ON(ret);
 843
 844         generation = btrfs_root_generation(&root->root_item);
 845         blocksize = btrfs_level_size(root, btrfs_root_level(&root->root_item));
 846         root->node = read_tree_block(root, btrfs_root_bytenr(&root->root_item),
 847                                      blocksize, generation);
 848         BUG_ON(!root->node);
 849         return 0;
 850 }
 851
 852 int btrfs_free_log_root_tree(struct btrfs_trans_handle *trans,
 853                              struct btrfs_fs_info *fs_info)
 854 {
 855         struct extent_buffer *eb;
 856         struct btrfs_root *log_root_tree = fs_info->log_root_tree;
 857         u64 start = 0;
 858         u64 end = 0;
 859         int ret;
 860
 861         if (!log_root_tree)
 862                 return 0;
 863
 864         while(1) {
 865                 ret = find_first_extent_bit(&log_root_tree->dirty_log_pages,
 866                                     0, &start, &end, EXTENT_DIRTY);
 867                 if (ret)
 868                         break;
 869
 870                 clear_extent_dirty(&log_root_tree->dirty_log_pages,
 871                                    start, end, GFP_NOFS);
 872         }
 873         eb = fs_info->log_root_tree->node;
 874
 875         WARN_ON(btrfs_header_level(eb) != 0);
 876         WARN_ON(btrfs_header_nritems(eb) != 0);
 877
 878         ret = btrfs_free_reserved_extent(fs_info->tree_root,
 879                                 eb->start, eb->len);
 880         BUG_ON(ret);
 881
 882         free_extent_buffer(eb);
 883         kfree(fs_info->log_root_tree);
 884         fs_info->log_root_tree = NULL;
 885         return 0;
 886 }
 887
 888 int btrfs_init_log_root_tree(struct btrfs_trans_handle *trans,
 889                              struct btrfs_fs_info *fs_info)
 890 {
 891         struct btrfs_root *root;
 892         struct btrfs_root *tree_root = fs_info->tree_root;
 893
 894         root = kzalloc(sizeof(*root), GFP_NOFS);
 895         if (!root)
 896                 return -ENOMEM;
 897
 898         __setup_root(tree_root->nodesize, tree_root->leafsize,
 899                      tree_root->sectorsize, tree_root->stripesize,
 900                      root, fs_info, BTRFS_TREE_LOG_OBJECTID);
 901
 902         root->root_key.objectid = BTRFS_TREE_LOG_OBJECTID;
 903         root->root_key.type = BTRFS_ROOT_ITEM_KEY;
 904         root->root_key.offset = BTRFS_TREE_LOG_OBJECTID;
 905         root->ref_cows = 0;
 906
 907         root->node = btrfs_alloc_free_block(trans, root, root->leafsize,
 908                                             0, BTRFS_TREE_LOG_OBJECTID,
 909                                             trans->transid, 0, 0, 0);
 910
 911         btrfs_set_header_nritems(root->node, 0);
 912         btrfs_set_header_level(root->node, 0);
 913         btrfs_set_header_bytenr(root->node, root->node->start);
 914         btrfs_set_header_generation(root->node, trans->transid);
 915         btrfs_set_header_owner(root->node, BTRFS_TREE_LOG_OBJECTID);
 916
 917         write_extent_buffer(root->node, root->fs_info->fsid,
 918                             (unsigned long)btrfs_header_fsid(root->node),
 919                             BTRFS_FSID_SIZE);
 920         btrfs_mark_buffer_dirty(root->node);
 921         btrfs_tree_unlock(root->node);
 922         fs_info->log_root_tree = root;
 923         return 0;
 924 }
 925
 926 struct btrfs_root *btrfs_read_fs_root_no_radix(struct btrfs_root *tree_root,
 927                                                struct btrfs_key *location)
 928 {
 929         struct btrfs_root *root;
 930         struct btrfs_fs_info *fs_info = tree_root->fs_info;
 931         struct btrfs_path *path;
 932         struct extent_buffer *l;
 933         u64 highest_inode;
 934         u64 generation;
 935         u32 blocksize;
 936         int ret = 0;
 937
 938         root = kzalloc(sizeof(*root), GFP_NOFS);
 939         if (!root)
 940                 return ERR_PTR(-ENOMEM);
 941         if (location->offset == (u64)-1) {
 942                 ret = find_and_setup_root(tree_root, fs_info,
 943                                           location->objectid, root);
 944                 if (ret) {
 945                         kfree(root);
 946                         return ERR_PTR(ret);
 947                 }
 948                 goto insert;
 949         }
 950
 951         __setup_root(tree_root->nodesize, tree_root->leafsize,
 952                      tree_root->sectorsize, tree_root->stripesize,
 953                      root, fs_info, location->objectid);
 954
 955         path = btrfs_alloc_path();
 956         BUG_ON(!path);
 957         ret = btrfs_search_slot(NULL, tree_root, location, path, 0, 0);
 958         if (ret != 0) {
 959                 if (ret > 0)
 960                         ret = -ENOENT;
 961                 goto out;
 962         }
 963         l = path->nodes[0];
 964         read_extent_buffer(l, &root->root_item,
 965                btrfs_item_ptr_offset(l, path->slots[0]),
 966                sizeof(root->root_item));
 967         memcpy(&root->root_key, location, sizeof(*location));
 968         ret = 0;
 969 out:
 970         btrfs_release_path(root, path);
 971         btrfs_free_path(path);
 972         if (ret) {
 973                 kfree(root);
 974                 return ERR_PTR(ret);
 975         }
 976         generation = btrfs_root_generation(&root->root_item);
 977         blocksize = btrfs_level_size(root, btrfs_root_level(&root->root_item));
 978         root->node = read_tree_block(root, btrfs_root_bytenr(&root->root_item),
 979                                      blocksize, generation);
 980         BUG_ON(!root->node);
 981 insert:
 982         if (location->objectid != BTRFS_TREE_LOG_OBJECTID) {
 983                 root->ref_cows = 1;
 984                 ret = btrfs_find_highest_inode(root, &highest_inode);
 985                 if (ret == 0) {
 986                         root->highest_inode = highest_inode;
 987                         root->last_inode_alloc = highest_inode;
 988                 }
 989         }
 990         return root;
 991 }
 992
 993 struct btrfs_root *btrfs_lookup_fs_root(struct btrfs_fs_info *fs_info,
 994                                         u64 root_objectid)
 995 {
 996         struct btrfs_root *root;
 997
 998         if (root_objectid == BTRFS_ROOT_TREE_OBJECTID)
 999                 return fs_info->tree_root;
1000         if (root_objectid == BTRFS_EXTENT_TREE_OBJECTID)
1001                 return fs_info->extent_root;
1002
1003         root = radix_tree_lookup(&fs_info->fs_roots_radix,
1004                                  (unsigned long)root_objectid);
1005         return root;
1006 }
1007
1008 struct btrfs_root *btrfs_read_fs_root_no_name(struct btrfs_fs_info *fs_info,
1009                                               struct btrfs_key *location)
1010 {
1011         struct btrfs_root *root;
1012         int ret;
1013
1014         if (location->objectid == BTRFS_ROOT_TREE_OBJECTID)
1015                 return fs_info->tree_root;
1016         if (location->objectid == BTRFS_EXTENT_TREE_OBJECTID)
1017                 return fs_info->extent_root;
1018         if (location->objectid == BTRFS_CHUNK_TREE_OBJECTID)
1019                 return fs_info->chunk_root;
1020         if (location->objectid == BTRFS_DEV_TREE_OBJECTID)
1021                 return fs_info->dev_root;
1022
1023         root = radix_tree_lookup(&fs_info->fs_roots_radix,
1024                                  (unsigned long)location->objectid);
1025         if (root)
1026                 return root;
1027
1028         root = btrfs_read_fs_root_no_radix(fs_info->tree_root, location);
1029         if (IS_ERR(root))
1030                 return root;
1031         ret = radix_tree_insert(&fs_info->fs_roots_radix,
1032                                 (unsigned long)root->root_key.objectid,
1033                                 root);
1034         if (ret) {
1035                 free_extent_buffer(root->node);
1036                 kfree(root);
1037                 return ERR_PTR(ret);
1038         }
1039         ret = btrfs_find_dead_roots(fs_info->tree_root,
1040                                     root->root_key.objectid, root);
1041         BUG_ON(ret);
1042
1043         return root;
1044 }
1045
1046 struct btrfs_root *btrfs_read_fs_root(struct btrfs_fs_info *fs_info,
1047                                       struct btrfs_key *location,
1048                                       const char *name, int namelen)
1049 {
1050         struct btrfs_root *root;
1051         int ret;
1052
1053         root = btrfs_read_fs_root_no_name(fs_info, location);
1054         if (!root)
1055                 return NULL;
1056
1057         if (root->in_sysfs)
1058                 return root;
1059
1060         ret = btrfs_set_root_name(root, name, namelen);
1061         if (ret) {
1062                 free_extent_buffer(root->node);
1063                 kfree(root);
1064                 return ERR_PTR(ret);
1065         }
1066
1067         ret = btrfs_sysfs_add_root(root);
1068         if (ret) {
1069                 free_extent_buffer(root->node);
1070                 kfree(root->name);
1071                 kfree(root);
1072                 return ERR_PTR(ret);
1073         }
1074         root->in_sysfs = 1;
1075         return root;
1076 }
1077 #if 0
1078 static int add_hasher(struct btrfs_fs_info *info, char *type) {
1079         struct btrfs_hasher *hasher;
1080
1081         hasher = kmalloc(sizeof(*hasher), GFP_NOFS);
1082         if (!hasher)
1083                 return -ENOMEM;
1084         hasher->hash_tfm = crypto_alloc_hash(type, 0, CRYPTO_ALG_ASYNC);
1085         if (!hasher->hash_tfm) {
1086                 kfree(hasher);
1087                 return -EINVAL;
1088         }
1089         spin_lock(&info->hash_lock);
1090         list_add(&hasher->list, &info->hashers);
1091         spin_unlock(&info->hash_lock);
1092         return 0;
1093 }
1094 #endif
1095
1096 static int btrfs_congested_fn(void *congested_data, int bdi_bits)
1097 {
1098         struct btrfs_fs_info *info = (struct btrfs_fs_info *)congested_data;
1099         int ret = 0;
1100         struct list_head *cur;
1101         struct btrfs_device *device;
1102         struct backing_dev_info *bdi;
1103
1104         if ((bdi_bits & (1 << BDI_write_congested)) &&
1105             btrfs_congested_async(info, 0))
1106                 return 1;
1107
1108         list_for_each(cur, &info->fs_devices->devices) {
1109                 device = list_entry(cur, struct btrfs_device, dev_list);
1110                 if (!device->bdev)
1111                         continue;
1112                 bdi = blk_get_backing_dev_info(device->bdev);
1113                 if (bdi && bdi_congested(bdi, bdi_bits)) {
1114                         ret = 1;
1115                         break;
1116                 }
1117         }
1118         return ret;
1119 }
1120
1121 /*
1122  * this unplugs every device on the box, and it is only used when page
1123  * is null
1124  */
1125 static void __unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
1126 {
1127         struct list_head *cur;
1128         struct btrfs_device *device;
1129         struct btrfs_fs_info *info;
1130
1131         info = (struct btrfs_fs_info *)bdi->unplug_io_data;
1132         list_for_each(cur, &info->fs_devices->devices) {
1133                 device = list_entry(cur, struct btrfs_device, dev_list);
1134                 bdi = blk_get_backing_dev_info(device->bdev);
1135                 if (bdi->unplug_io_fn) {
1136                         bdi->unplug_io_fn(bdi, page);
1137                 }
1138         }
1139 }
1140
1141 void btrfs_unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
1142 {
1143         struct inode *inode;
1144         struct extent_map_tree *em_tree;
1145         struct extent_map *em;
1146         struct address_space *mapping;
1147         u64 offset;
1148
1149         /* the generic O_DIRECT read code does this */
1150         if (!page) {
1151                 __unplug_io_fn(bdi, page);
1152                 return;
1153         }
1154
1155         /*
1156          * page->mapping may change at any time.  Get a consistent copy
1157          * and use that for everything below
1158          */
1159         smp_mb();
1160         mapping = page->mapping;
1161         if (!mapping)
1162                 return;
1163
1164         inode = mapping->host;
1165         offset = page_offset(page);
1166
1167         em_tree = &BTRFS_I(inode)->extent_tree;
1168         spin_lock(&em_tree->lock);
1169         em = lookup_extent_mapping(em_tree, offset, PAGE_CACHE_SIZE);
1170         spin_unlock(&em_tree->lock);
1171         if (!em) {
1172                 __unplug_io_fn(bdi, page);
1173                 return;
1174         }
1175
1176         if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
1177                 free_extent_map(em);
1178                 __unplug_io_fn(bdi, page);
1179                 return;
1180         }
1181         offset = offset - em->start;
1182         btrfs_unplug_page(&BTRFS_I(inode)->root->fs_info->mapping_tree,
1183                           em->block_start + offset, page);
1184         free_extent_map(em);
1185 }
1186
1187 static int setup_bdi(struct btrfs_fs_info *info, struct backing_dev_info *bdi)
1188 {
1189         bdi_init(bdi);
1190         bdi->ra_pages   = default_backing_dev_info.ra_pages;
1191         bdi->state              = 0;
1192         bdi->capabilities       = default_backing_dev_info.capabilities;
1193         bdi->unplug_io_fn       = btrfs_unplug_io_fn;
1194         bdi->unplug_io_data     = info;
1195         bdi->congested_fn       = btrfs_congested_fn;
1196         bdi->congested_data     = info;
1197         return 0;
1198 }
1199
1200 static int bio_ready_for_csum(struct bio *bio)
1201 {
1202         u64 length = 0;
1203         u64 buf_len = 0;
1204         u64 start = 0;
1205         struct page *page;
1206         struct extent_io_tree *io_tree = NULL;
1207         struct btrfs_fs_info *info = NULL;
1208         struct bio_vec *bvec;
1209         int i;
1210         int ret;
1211
1212         bio_for_each_segment(bvec, bio, i) {
1213                 page = bvec->bv_page;
1214                 if (page->private == EXTENT_PAGE_PRIVATE) {
1215                         length += bvec->bv_len;
1216                         continue;
1217                 }
1218                 if (!page->private) {
1219                         length += bvec->bv_len;
1220                         continue;
1221                 }
1222                 length = bvec->bv_len;
1223                 buf_len = page->private >> 2;
1224                 start = page_offset(page) + bvec->bv_offset;
1225                 io_tree = &BTRFS_I(page->mapping->host)->io_tree;
1226                 info = BTRFS_I(page->mapping->host)->root->fs_info;
1227         }
1228         /* are we fully contained in this bio? */
1229         if (buf_len <= length)
1230                 return 1;
1231
1232         ret = extent_range_uptodate(io_tree, start + length,
1233                                     start + buf_len - 1);
1234         if (ret == 1)
1235                 return ret;
1236         return ret;
1237 }
1238
1239 /*
1240  * called by the kthread helper functions to finally call the bio end_io
1241  * functions.  This is where read checksum verification actually happens
1242  */
1243 static void end_workqueue_fn(struct btrfs_work *work)
1244 {
1245         struct bio *bio;
1246         struct end_io_wq *end_io_wq;
1247         struct btrfs_fs_info *fs_info;
1248         int error;
1249
1250         end_io_wq = container_of(work, struct end_io_wq, work);
1251         bio = end_io_wq->bio;
1252         fs_info = end_io_wq->info;
1253
1254         /* metadata bios are special because the whole tree block must
1255          * be checksummed at once.  This makes sure the entire block is in
1256          * ram and up to date before trying to verify things.  For
1257          * blocksize <= pagesize, it is basically a noop
1258          */
1259         if (end_io_wq->metadata && !bio_ready_for_csum(bio)) {
1260                 btrfs_queue_worker(&fs_info->endio_workers,
1261                                    &end_io_wq->work);
1262                 return;
1263         }
1264         error = end_io_wq->error;
1265         bio->bi_private = end_io_wq->private;
1266         bio->bi_end_io = end_io_wq->end_io;
1267         kfree(end_io_wq);
1268         bio_endio(bio, error);
1269 }
1270
1271 static int cleaner_kthread(void *arg)
1272 {
1273         struct btrfs_root *root = arg;
1274
1275         do {
1276                 smp_mb();
1277                 if (root->fs_info->closing)
1278                         break;
1279
1280                 vfs_check_frozen(root->fs_info->sb, SB_FREEZE_WRITE);
1281                 mutex_lock(&root->fs_info->cleaner_mutex);
1282                 btrfs_clean_old_snapshots(root);
1283                 mutex_unlock(&root->fs_info->cleaner_mutex);
1284
1285                 if (freezing(current)) {
1286                         refrigerator();
1287                 } else {
1288                         smp_mb();
1289                         if (root->fs_info->closing)
1290                                 break;
1291                         set_current_state(TASK_INTERRUPTIBLE);
1292                         schedule();
1293                         __set_current_state(TASK_RUNNING);
1294                 }
1295         } while (!kthread_should_stop());
1296         return 0;
1297 }
1298
1299 static int transaction_kthread(void *arg)
1300 {
1301         struct btrfs_root *root = arg;
1302         struct btrfs_trans_handle *trans;
1303         struct btrfs_transaction *cur;
1304         unsigned long now;
1305         unsigned long delay;
1306         int ret;
1307
1308         do {
1309                 smp_mb();
1310                 if (root->fs_info->closing)
1311                         break;
1312
1313                 delay = HZ * 30;
1314                 vfs_check_frozen(root->fs_info->sb, SB_FREEZE_WRITE);
1315                 mutex_lock(&root->fs_info->transaction_kthread_mutex);
1316
1317                 if (root->fs_info->total_ref_cache_size > 20 * 1024 * 1024) {
1318                         printk("btrfs: total reference cache size %Lu\n",
1319                                 root->fs_info->total_ref_cache_size);
1320                 }
1321
1322                 mutex_lock(&root->fs_info->trans_mutex);
1323                 cur = root->fs_info->running_transaction;
1324                 if (!cur) {
1325                         mutex_unlock(&root->fs_info->trans_mutex);
1326                         goto sleep;
1327                 }
1328
1329                 now = get_seconds();
1330                 if (now < cur->start_time || now - cur->start_time < 30) {
1331                         mutex_unlock(&root->fs_info->trans_mutex);
1332                         delay = HZ * 5;
1333                         goto sleep;
1334                 }
1335                 mutex_unlock(&root->fs_info->trans_mutex);
1336                 trans = btrfs_start_transaction(root, 1);
1337                 ret = btrfs_commit_transaction(trans, root);
1338 sleep:
1339                 wake_up_process(root->fs_info->cleaner_kthread);
1340                 mutex_unlock(&root->fs_info->transaction_kthread_mutex);
1341
1342                 if (freezing(current)) {
1343                         refrigerator();
1344                 } else {
1345                         if (root->fs_info->closing)
1346                                 break;
1347                         set_current_state(TASK_INTERRUPTIBLE);
1348                         schedule_timeout(delay);
1349                         __set_current_state(TASK_RUNNING);
1350                 }
1351         } while (!kthread_should_stop());
1352         return 0;
1353 }
1354
1355 struct btrfs_root *open_ctree(struct super_block *sb,
1356                               struct btrfs_fs_devices *fs_devices,
1357                               char *options)
1358 {
1359         u32 sectorsize;
1360         u32 nodesize;
1361         u32 leafsize;
1362         u32 blocksize;
1363         u32 stripesize;
1364         u64 generation;
1365         struct buffer_head *bh;
1366         struct btrfs_root *extent_root = kzalloc(sizeof(struct btrfs_root),
1367                                                  GFP_NOFS);
1368         struct btrfs_root *tree_root = kzalloc(sizeof(struct btrfs_root),
1369                                                GFP_NOFS);
1370         struct btrfs_fs_info *fs_info = kzalloc(sizeof(*fs_info),
1371                                                 GFP_NOFS);
1372         struct btrfs_root *chunk_root = kzalloc(sizeof(struct btrfs_root),
1373                                                 GFP_NOFS);
1374         struct btrfs_root *dev_root = kzalloc(sizeof(struct btrfs_root),
1375                                               GFP_NOFS);
1376         struct btrfs_root *log_tree_root;
1377
1378         int ret;
1379         int err = -EINVAL;
1380
1381         struct btrfs_super_block *disk_super;
1382
1383         if (!extent_root || !tree_root || !fs_info ||
1384             !chunk_root || !dev_root) {
1385                 err = -ENOMEM;
1386                 goto fail;
1387         }
1388         INIT_RADIX_TREE(&fs_info->fs_roots_radix, GFP_NOFS);
1389         INIT_LIST_HEAD(&fs_info->trans_list);
1390         INIT_LIST_HEAD(&fs_info->dead_roots);
1391         INIT_LIST_HEAD(&fs_info->hashers);
1392         INIT_LIST_HEAD(&fs_info->delalloc_inodes);
1393         spin_lock_init(&fs_info->hash_lock);
1394         spin_lock_init(&fs_info->delalloc_lock);
1395         spin_lock_init(&fs_info->new_trans_lock);
1396         spin_lock_init(&fs_info->ref_cache_lock);
1397
1398         init_completion(&fs_info->kobj_unregister);
1399         fs_info->tree_root = tree_root;
1400         fs_info->extent_root = extent_root;
1401         fs_info->chunk_root = chunk_root;
1402         fs_info->dev_root = dev_root;
1403         fs_info->fs_devices = fs_devices;
1404         INIT_LIST_HEAD(&fs_info->dirty_cowonly_roots);
1405         INIT_LIST_HEAD(&fs_info->space_info);
1406         btrfs_mapping_init(&fs_info->mapping_tree);
1407         atomic_set(&fs_info->nr_async_submits, 0);
1408         atomic_set(&fs_info->async_submit_draining, 0);
1409         atomic_set(&fs_info->nr_async_bios, 0);
1410         atomic_set(&fs_info->throttles, 0);
1411         atomic_set(&fs_info->throttle_gen, 0);
1412         fs_info->sb = sb;
1413         fs_info->max_extent = (u64)-1;
1414         fs_info->max_inline = 8192 * 1024;
1415         setup_bdi(fs_info, &fs_info->bdi);
1416         fs_info->btree_inode = new_inode(sb);
1417         fs_info->btree_inode->i_ino = 1;
1418         fs_info->btree_inode->i_nlink = 1;
1419
1420         fs_info->thread_pool_size = min(num_online_cpus() + 2, 8);
1421
1422         INIT_LIST_HEAD(&fs_info->ordered_extents);
1423         spin_lock_init(&fs_info->ordered_extent_lock);
1424
1425         sb->s_blocksize = 4096;
1426         sb->s_blocksize_bits = blksize_bits(4096);
1427
1428         /*
1429          * we set the i_size on the btree inode to the max possible int.
1430          * the real end of the address space is determined by all of
1431          * the devices in the system
1432          */
1433         fs_info->btree_inode->i_size = OFFSET_MAX;
1434         fs_info->btree_inode->i_mapping->a_ops = &btree_aops;
1435         fs_info->btree_inode->i_mapping->backing_dev_info = &fs_info->bdi;
1436
1437         extent_io_tree_init(&BTRFS_I(fs_info->btree_inode)->io_tree,
1438                              fs_info->btree_inode->i_mapping,
1439                              GFP_NOFS);
1440         extent_map_tree_init(&BTRFS_I(fs_info->btree_inode)->extent_tree,
1441                              GFP_NOFS);
1442
1443         BTRFS_I(fs_info->btree_inode)->io_tree.ops = &btree_extent_io_ops;
1444
1445         spin_lock_init(&fs_info->block_group_cache_lock);
1446         fs_info->block_group_cache_tree.rb_node = NULL;
1447
1448         extent_io_tree_init(&fs_info->pinned_extents,
1449                              fs_info->btree_inode->i_mapping, GFP_NOFS);
1450         extent_io_tree_init(&fs_info->pending_del,
1451                              fs_info->btree_inode->i_mapping, GFP_NOFS);
1452         extent_io_tree_init(&fs_info->extent_ins,
1453                              fs_info->btree_inode->i_mapping, GFP_NOFS);
1454         fs_info->do_barriers = 1;
1455
1456         INIT_LIST_HEAD(&fs_info->dead_reloc_roots);
1457         btrfs_leaf_ref_tree_init(&fs_info->reloc_ref_tree);
1458         btrfs_leaf_ref_tree_init(&fs_info->shared_ref_tree);
1459
1460         BTRFS_I(fs_info->btree_inode)->root = tree_root;
1461         memset(&BTRFS_I(fs_info->btree_inode)->location, 0,
1462                sizeof(struct btrfs_key));
1463         insert_inode_hash(fs_info->btree_inode);
1464
1465         mutex_init(&fs_info->trans_mutex);
1466         mutex_init(&fs_info->tree_log_mutex);
1467         mutex_init(&fs_info->drop_mutex);
1468         mutex_init(&fs_info->extent_ins_mutex);
1469         mutex_init(&fs_info->pinned_mutex);
1470         mutex_init(&fs_info->chunk_mutex);
1471         mutex_init(&fs_info->transaction_kthread_mutex);
1472         mutex_init(&fs_info->cleaner_mutex);
1473         mutex_init(&fs_info->volume_mutex);
1474         mutex_init(&fs_info->tree_reloc_mutex);
1475         init_waitqueue_head(&fs_info->transaction_throttle);
1476         init_waitqueue_head(&fs_info->transaction_wait);
1477         init_waitqueue_head(&fs_info->async_submit_wait);
1478         init_waitqueue_head(&fs_info->tree_log_wait);
1479         atomic_set(&fs_info->tree_log_commit, 0);
1480         atomic_set(&fs_info->tree_log_writers, 0);
1481         fs_info->tree_log_transid = 0;
1482
1483 #if 0
1484         ret = add_hasher(fs_info, "crc32c");
1485         if (ret) {
1486                 printk("btrfs: failed hash setup, modprobe cryptomgr?\n");
1487                 err = -ENOMEM;
1488                 goto fail_iput;
1489         }
1490 #endif
1491         __setup_root(4096, 4096, 4096, 4096, tree_root,
1492                      fs_info, BTRFS_ROOT_TREE_OBJECTID);
1493
1494
1495         bh = __bread(fs_devices->latest_bdev,
1496                      BTRFS_SUPER_INFO_OFFSET / 4096, 4096);
1497         if (!bh)
1498                 goto fail_iput;
1499
1500         memcpy(&fs_info->super_copy, bh->b_data, sizeof(fs_info->super_copy));
1501         brelse(bh);
1502
1503         memcpy(fs_info->fsid, fs_info->super_copy.fsid, BTRFS_FSID_SIZE);
1504
1505         disk_super = &fs_info->super_copy;
1506         if (!btrfs_super_root(disk_super))
1507                 goto fail_sb_buffer;
1508
1509         err = btrfs_parse_options(tree_root, options);
1510         if (err)
1511                 goto fail_sb_buffer;
1512
1513         /*
1514          * we need to start all the end_io workers up front because the
1515          * queue work function gets called at interrupt time, and so it
1516          * cannot dynamically grow.
1517          */
1518         btrfs_init_workers(&fs_info->workers, "worker",
1519                            fs_info->thread_pool_size);
1520
1521         btrfs_init_workers(&fs_info->submit_workers, "submit",
1522                            min_t(u64, fs_devices->num_devices,
1523                            fs_info->thread_pool_size));
1524
1525         /* a higher idle thresh on the submit workers makes it much more
1526          * likely that bios will be send down in a sane order to the
1527          * devices
1528          */
1529         fs_info->submit_workers.idle_thresh = 64;
1530
1531         /* fs_info->workers is responsible for checksumming file data
1532          * blocks and metadata.  Using a larger idle thresh allows each
1533          * worker thread to operate on things in roughly the order they
1534          * were sent by the writeback daemons, improving overall locality
1535          * of the IO going down the pipe.
1536          */
1537         fs_info->workers.idle_thresh = 128;
1538
1539         btrfs_init_workers(&fs_info->fixup_workers, "fixup", 1);
1540         btrfs_init_workers(&fs_info->endio_workers, "endio",
1541                            fs_info->thread_pool_size);
1542         btrfs_init_workers(&fs_info->endio_write_workers, "endio-write",
1543                            fs_info->thread_pool_size);
1544
1545         /*
1546          * endios are largely parallel and should have a very
1547          * low idle thresh
1548          */
1549         fs_info->endio_workers.idle_thresh = 4;
1550         fs_info->endio_write_workers.idle_thresh = 64;
1551
1552         btrfs_start_workers(&fs_info->workers, 1);
1553         btrfs_start_workers(&fs_info->submit_workers, 1);
1554         btrfs_start_workers(&fs_info->fixup_workers, 1);
1555         btrfs_start_workers(&fs_info->endio_workers, fs_info->thread_pool_size);
1556         btrfs_start_workers(&fs_info->endio_write_workers,
1557                             fs_info->thread_pool_size);
1558
1559         err = -EINVAL;
1560         if (btrfs_super_num_devices(disk_super) > fs_devices->open_devices) {
1561                 printk("Btrfs: wanted %llu devices, but found %llu\n",
1562                        (unsigned long long)btrfs_super_num_devices(disk_super),
1563                        (unsigned long long)fs_devices->open_devices);
1564                 if (btrfs_test_opt(tree_root, DEGRADED))
1565                         printk("continuing in degraded mode\n");
1566                 else {
1567                         goto fail_sb_buffer;
1568                 }
1569         }
1570
1571         fs_info->bdi.ra_pages *= btrfs_super_num_devices(disk_super);
1572         fs_info->bdi.ra_pages = max(fs_info->bdi.ra_pages,
1573                                     4 * 1024 * 1024 / PAGE_CACHE_SIZE);
1574
1575         nodesize = btrfs_super_nodesize(disk_super);
1576         leafsize = btrfs_super_leafsize(disk_super);
1577         sectorsize = btrfs_super_sectorsize(disk_super);
1578         stripesize = btrfs_super_stripesize(disk_super);
1579         tree_root->nodesize = nodesize;
1580         tree_root->leafsize = leafsize;
1581         tree_root->sectorsize = sectorsize;
1582         tree_root->stripesize = stripesize;
1583
1584         sb->s_blocksize = sectorsize;
1585         sb->s_blocksize_bits = blksize_bits(sectorsize);
1586
1587         if (strncmp((char *)(&disk_super->magic), BTRFS_MAGIC,
1588                     sizeof(disk_super->magic))) {
1589                 printk("btrfs: valid FS not found on %s\n", sb->s_id);
1590                 goto fail_sb_buffer;
1591         }
1592
1593         mutex_lock(&fs_info->chunk_mutex);
1594         ret = btrfs_read_sys_array(tree_root);
1595         mutex_unlock(&fs_info->chunk_mutex);
1596         if (ret) {
1597                 printk("btrfs: failed to read the system array on %s\n",
1598                        sb->s_id);
1599                 goto fail_sys_array;
1600         }
1601
1602         blocksize = btrfs_level_size(tree_root,
1603                                      btrfs_super_chunk_root_level(disk_super));
1604         generation = btrfs_super_chunk_root_generation(disk_super);
1605
1606         __setup_root(nodesize, leafsize, sectorsize, stripesize,
1607                      chunk_root, fs_info, BTRFS_CHUNK_TREE_OBJECTID);
1608
1609         chunk_root->node = read_tree_block(chunk_root,
1610                                            btrfs_super_chunk_root(disk_super),
1611                                            blocksize, generation);
1612         BUG_ON(!chunk_root->node);
1613
1614         read_extent_buffer(chunk_root->node, fs_info->chunk_tree_uuid,
1615                  (unsigned long)btrfs_header_chunk_tree_uuid(chunk_root->node),
1616                  BTRFS_UUID_SIZE);
1617
1618         mutex_lock(&fs_info->chunk_mutex);
1619         ret = btrfs_read_chunk_tree(chunk_root);
1620         mutex_unlock(&fs_info->chunk_mutex);
1621         BUG_ON(ret);
1622
1623         btrfs_close_extra_devices(fs_devices);
1624
1625         blocksize = btrfs_level_size(tree_root,
1626                                      btrfs_super_root_level(disk_super));
1627         generation = btrfs_super_generation(disk_super);
1628
1629         tree_root->node = read_tree_block(tree_root,
1630                                           btrfs_super_root(disk_super),
1631                                           blocksize, generation);
1632         if (!tree_root->node)
1633                 goto fail_sb_buffer;
1634
1635
1636         ret = find_and_setup_root(tree_root, fs_info,
1637                                   BTRFS_EXTENT_TREE_OBJECTID, extent_root);
1638         if (ret)
1639                 goto fail_tree_root;
1640         extent_root->track_dirty = 1;
1641
1642         ret = find_and_setup_root(tree_root, fs_info,
1643                                   BTRFS_DEV_TREE_OBJECTID, dev_root);
1644         dev_root->track_dirty = 1;
1645
1646         if (ret)
1647                 goto fail_extent_root;
1648
1649         btrfs_read_block_groups(extent_root);
1650
1651         fs_info->generation = btrfs_super_generation(disk_super) + 1;
1652         fs_info->data_alloc_profile = (u64)-1;
1653         fs_info->metadata_alloc_profile = (u64)-1;
1654         fs_info->system_alloc_profile = fs_info->metadata_alloc_profile;
1655         fs_info->cleaner_kthread = kthread_run(cleaner_kthread, tree_root,
1656                                                "btrfs-cleaner");
1657         if (!fs_info->cleaner_kthread)
1658                 goto fail_extent_root;
1659
1660         fs_info->transaction_kthread = kthread_run(transaction_kthread,
1661                                                    tree_root,
1662                                                    "btrfs-transaction");
1663         if (!fs_info->transaction_kthread)
1664                 goto fail_cleaner;
1665
1666         if (btrfs_super_log_root(disk_super) != 0) {
1667                 u32 blocksize;
1668                 u64 bytenr = btrfs_super_log_root(disk_super);
1669
1670                 blocksize =
1671                      btrfs_level_size(tree_root,
1672                                       btrfs_super_log_root_level(disk_super));
1673
1674                 log_tree_root = kzalloc(sizeof(struct btrfs_root),
1675                                                       GFP_NOFS);
1676
1677                 __setup_root(nodesize, leafsize, sectorsize, stripesize,
1678                              log_tree_root, fs_info, BTRFS_TREE_LOG_OBJECTID);
1679
1680                 log_tree_root->node = read_tree_block(tree_root, bytenr,
1681                                                       blocksize,
1682                                                       generation + 1);
1683                 ret = btrfs_recover_log_trees(log_tree_root);
1684                 BUG_ON(ret);
1685         }
1686         fs_info->last_trans_committed = btrfs_super_generation(disk_super);
1687
1688         ret = btrfs_cleanup_reloc_trees(tree_root);
1689         BUG_ON(ret);
1690
1691         return tree_root;
1692
1693 fail_cleaner:
1694         kthread_stop(fs_info->cleaner_kthread);
1695 fail_extent_root:
1696         free_extent_buffer(extent_root->node);
1697 fail_tree_root:
1698         free_extent_buffer(tree_root->node);
1699 fail_sys_array:
1700 fail_sb_buffer:
1701         btrfs_stop_workers(&fs_info->fixup_workers);
1702         btrfs_stop_workers(&fs_info->workers);
1703         btrfs_stop_workers(&fs_info->endio_workers);
1704         btrfs_stop_workers(&fs_info->endio_write_workers);
1705         btrfs_stop_workers(&fs_info->submit_workers);
1706 fail_iput:
1707         iput(fs_info->btree_inode);
1708 fail:
1709         btrfs_close_devices(fs_info->fs_devices);
1710         btrfs_mapping_tree_free(&fs_info->mapping_tree);
1711
1712         kfree(extent_root);
1713         kfree(tree_root);
1714         bdi_destroy(&fs_info->bdi);
1715         kfree(fs_info);
1716         kfree(chunk_root);
1717         kfree(dev_root);
1718         return ERR_PTR(err);
1719 }
1720
1721 static void btrfs_end_buffer_write_sync(struct buffer_head *bh, int uptodate)
1722 {
1723         char b[BDEVNAME_SIZE];
1724
1725         if (uptodate) {
1726                 set_buffer_uptodate(bh);
1727         } else {
1728                 if (!buffer_eopnotsupp(bh) && printk_ratelimit()) {
1729                         printk(KERN_WARNING "lost page write due to "
1730                                         "I/O error on %s\n",
1731                                        bdevname(bh->b_bdev, b));
1732                 }
1733                 /* note, we dont' set_buffer_write_io_error because we have
1734                  * our own ways of dealing with the IO errors
1735                  */
1736                 clear_buffer_uptodate(bh);
1737         }
1738         unlock_buffer(bh);
1739         put_bh(bh);
1740 }
1741
1742 int write_all_supers(struct btrfs_root *root)
1743 {
1744         struct list_head *cur;
1745         struct list_head *head = &root->fs_info->fs_devices->devices;
1746         struct btrfs_device *dev;
1747         struct btrfs_super_block *sb;
1748         struct btrfs_dev_item *dev_item;
1749         struct buffer_head *bh;
1750         int ret;
1751         int do_barriers;
1752         int max_errors;
1753         int total_errors = 0;
1754         u32 crc;
1755         u64 flags;
1756
1757         max_errors = btrfs_super_num_devices(&root->fs_info->super_copy) - 1;
1758         do_barriers = !btrfs_test_opt(root, NOBARRIER);
1759
1760         sb = &root->fs_info->super_for_commit;
1761         dev_item = &sb->dev_item;
1762         list_for_each(cur, head) {
1763                 dev = list_entry(cur, struct btrfs_device, dev_list);
1764                 if (!dev->bdev) {
1765                         total_errors++;
1766                         continue;
1767                 }
1768                 if (!dev->in_fs_metadata)
1769                         continue;
1770
1771                 btrfs_set_stack_device_type(dev_item, dev->type);
1772                 btrfs_set_stack_device_id(dev_item, dev->devid);
1773                 btrfs_set_stack_device_total_bytes(dev_item, dev->total_bytes);
1774                 btrfs_set_stack_device_bytes_used(dev_item, dev->bytes_used);
1775                 btrfs_set_stack_device_io_align(dev_item, dev->io_align);
1776                 btrfs_set_stack_device_io_width(dev_item, dev->io_width);
1777                 btrfs_set_stack_device_sector_size(dev_item, dev->sector_size);
1778                 memcpy(dev_item->uuid, dev->uuid, BTRFS_UUID_SIZE);
1779                 flags = btrfs_super_flags(sb);
1780                 btrfs_set_super_flags(sb, flags | BTRFS_HEADER_FLAG_WRITTEN);
1781
1782
1783                 crc = ~(u32)0;
1784                 crc = btrfs_csum_data(root, (char *)sb + BTRFS_CSUM_SIZE, crc,
1785                                       BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE);
1786                 btrfs_csum_final(crc, sb->csum);
1787
1788                 bh = __getblk(dev->bdev, BTRFS_SUPER_INFO_OFFSET / 4096,
1789                               BTRFS_SUPER_INFO_SIZE);
1790
1791                 memcpy(bh->b_data, sb, BTRFS_SUPER_INFO_SIZE);
1792                 dev->pending_io = bh;
1793
1794                 get_bh(bh);
1795                 set_buffer_uptodate(bh);
1796                 lock_buffer(bh);
1797                 bh->b_end_io = btrfs_end_buffer_write_sync;
1798
1799                 if (do_barriers && dev->barriers) {
1800                         ret = submit_bh(WRITE_BARRIER, bh);
1801                         if (ret == -EOPNOTSUPP) {
1802                                 printk("btrfs: disabling barriers on dev %s\n",
1803                                        dev->name);
1804                                 set_buffer_uptodate(bh);
1805                                 dev->barriers = 0;
1806                                 get_bh(bh);
1807                                 lock_buffer(bh);
1808                                 ret = submit_bh(WRITE, bh);
1809                         }
1810                 } else {
1811                         ret = submit_bh(WRITE, bh);
1812                 }
1813                 if (ret)
1814                         total_errors++;
1815         }
1816         if (total_errors > max_errors) {
1817                 printk("btrfs: %d errors while writing supers\n", total_errors);
1818                 BUG();
1819         }
1820         total_errors = 0;
1821
1822         list_for_each(cur, head) {
1823                 dev = list_entry(cur, struct btrfs_device, dev_list);
1824                 if (!dev->bdev)
1825                         continue;
1826                 if (!dev->in_fs_metadata)
1827                         continue;
1828
1829                 BUG_ON(!dev->pending_io);
1830                 bh = dev->pending_io;
1831                 wait_on_buffer(bh);
1832                 if (!buffer_uptodate(dev->pending_io)) {
1833                         if (do_barriers && dev->barriers) {
1834                                 printk("btrfs: disabling barriers on dev %s\n",
1835                                        dev->name);
1836                                 set_buffer_uptodate(bh);
1837                                 get_bh(bh);
1838                                 lock_buffer(bh);
1839                                 dev->barriers = 0;
1840                                 ret = submit_bh(WRITE, bh);
1841                                 BUG_ON(ret);
1842                                 wait_on_buffer(bh);
1843                                 if (!buffer_uptodate(bh))
1844                                         total_errors++;
1845                         } else {
1846                                 total_errors++;
1847                         }
1848
1849                 }
1850                 dev->pending_io = NULL;
1851                 brelse(bh);
1852         }
1853         if (total_errors > max_errors) {
1854                 printk("btrfs: %d errors while writing supers\n", total_errors);
1855                 BUG();
1856         }
1857         return 0;
1858 }
1859
1860 int write_ctree_super(struct btrfs_trans_handle *trans, struct btrfs_root
1861                       *root)
1862 {
1863         int ret;
1864
1865         ret = write_all_supers(root);
1866         return ret;
1867 }
1868
1869 int btrfs_free_fs_root(struct btrfs_fs_info *fs_info, struct btrfs_root *root)
1870 {
1871         radix_tree_delete(&fs_info->fs_roots_radix,
1872                           (unsigned long)root->root_key.objectid);
1873         if (root->in_sysfs)
1874                 btrfs_sysfs_del_root(root);
1875         if (root->inode)
1876                 iput(root->inode);
1877         if (root->node)
1878                 free_extent_buffer(root->node);
1879         if (root->commit_root)
1880                 free_extent_buffer(root->commit_root);
1881         if (root->name)
1882                 kfree(root->name);
1883         kfree(root);
1884         return 0;
1885 }
1886
1887 static int del_fs_roots(struct btrfs_fs_info *fs_info)
1888 {
1889         int ret;
1890         struct btrfs_root *gang[8];
1891         int i;
1892
1893         while(1) {
1894                 ret = radix_tree_gang_lookup(&fs_info->fs_roots_radix,
1895                                              (void **)gang, 0,
1896                                              ARRAY_SIZE(gang));
1897                 if (!ret)
1898                         break;
1899                 for (i = 0; i < ret; i++)
1900                         btrfs_free_fs_root(fs_info, gang[i]);
1901         }
1902         return 0;
1903 }
1904
1905 int close_ctree(struct btrfs_root *root)
1906 {
1907         int ret;
1908         struct btrfs_trans_handle *trans;
1909         struct btrfs_fs_info *fs_info = root->fs_info;
1910
1911         fs_info->closing = 1;
1912         smp_mb();
1913
1914         kthread_stop(root->fs_info->transaction_kthread);
1915         kthread_stop(root->fs_info->cleaner_kthread);
1916
1917         btrfs_clean_old_snapshots(root);
1918         trans = btrfs_start_transaction(root, 1);
1919         ret = btrfs_commit_transaction(trans, root);
1920         /* run commit again to  drop the original snapshot */
1921         trans = btrfs_start_transaction(root, 1);
1922         btrfs_commit_transaction(trans, root);
1923         ret = btrfs_write_and_wait_transaction(NULL, root);
1924         BUG_ON(ret);
1925
1926         write_ctree_super(NULL, root);
1927
1928         if (fs_info->delalloc_bytes) {
1929                 printk("btrfs: at unmount delalloc count %Lu\n",
1930                        fs_info->delalloc_bytes);
1931         }
1932         if (fs_info->total_ref_cache_size) {
1933                 printk("btrfs: at umount reference cache size %Lu\n",
1934                         fs_info->total_ref_cache_size);
1935         }
1936
1937         if (fs_info->extent_root->node)
1938                 free_extent_buffer(fs_info->extent_root->node);
1939
1940         if (fs_info->tree_root->node)
1941                 free_extent_buffer(fs_info->tree_root->node);
1942
1943         if (root->fs_info->chunk_root->node);
1944                 free_extent_buffer(root->fs_info->chunk_root->node);
1945
1946         if (root->fs_info->dev_root->node);
1947                 free_extent_buffer(root->fs_info->dev_root->node);
1948
1949         btrfs_free_block_groups(root->fs_info);
1950         fs_info->closing = 2;
1951         del_fs_roots(fs_info);
1952
1953         filemap_write_and_wait(fs_info->btree_inode->i_mapping);
1954
1955         truncate_inode_pages(fs_info->btree_inode->i_mapping, 0);
1956
1957         btrfs_stop_workers(&fs_info->fixup_workers);
1958         btrfs_stop_workers(&fs_info->workers);
1959         btrfs_stop_workers(&fs_info->endio_workers);
1960         btrfs_stop_workers(&fs_info->endio_write_workers);
1961         btrfs_stop_workers(&fs_info->submit_workers);
1962
1963         iput(fs_info->btree_inode);
1964 #if 0
1965         while(!list_empty(&fs_info->hashers)) {
1966                 struct btrfs_hasher *hasher;
1967                 hasher = list_entry(fs_info->hashers.next, struct btrfs_hasher,
1968                                     hashers);
1969                 list_del(&hasher->hashers);
1970                 crypto_free_hash(&fs_info->hash_tfm);
1971                 kfree(hasher);
1972         }
1973 #endif
1974         btrfs_close_devices(fs_info->fs_devices);
1975         btrfs_mapping_tree_free(&fs_info->mapping_tree);
1976
1977         bdi_destroy(&fs_info->bdi);
1978
1979         kfree(fs_info->extent_root);
1980         kfree(fs_info->tree_root);
1981         kfree(fs_info->chunk_root);
1982         kfree(fs_info->dev_root);
1983         return 0;
1984 }
1985
1986 int btrfs_buffer_uptodate(struct extent_buffer *buf, u64 parent_transid)
1987 {
1988         int ret;
1989         struct inode *btree_inode = buf->first_page->mapping->host;
1990
1991         ret = extent_buffer_uptodate(&BTRFS_I(btree_inode)->io_tree, buf);
1992         if (!ret)
1993                 return ret;
1994
1995         ret = verify_parent_transid(&BTRFS_I(btree_inode)->io_tree, buf,
1996                                     parent_transid);
1997         return !ret;
1998 }
1999
2000 int btrfs_set_buffer_uptodate(struct extent_buffer *buf)
2001 {
2002         struct inode *btree_inode = buf->first_page->mapping->host;
2003         return set_extent_buffer_uptodate(&BTRFS_I(btree_inode)->io_tree,
2004                                           buf);
2005 }
2006
2007 void btrfs_mark_buffer_dirty(struct extent_buffer *buf)
2008 {
2009         struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;
2010         u64 transid = btrfs_header_generation(buf);
2011         struct inode *btree_inode = root->fs_info->btree_inode;
2012
2013         WARN_ON(!btrfs_tree_locked(buf));
2014         if (transid != root->fs_info->generation) {
2015                 printk(KERN_CRIT "transid mismatch buffer %llu, found %Lu running %Lu\n",
2016                         (unsigned long long)buf->start,
2017                         transid, root->fs_info->generation);
2018                 WARN_ON(1);
2019         }
2020         set_extent_buffer_dirty(&BTRFS_I(btree_inode)->io_tree, buf);
2021 }
2022
2023 void btrfs_btree_balance_dirty(struct btrfs_root *root, unsigned long nr)
2024 {
2025         /*
2026          * looks as though older kernels can get into trouble with
2027          * this code, they end up stuck in balance_dirty_pages forever
2028          */
2029         struct extent_io_tree *tree;
2030         u64 num_dirty;
2031         u64 start = 0;
2032         unsigned long thresh = 96 * 1024 * 1024;
2033         tree = &BTRFS_I(root->fs_info->btree_inode)->io_tree;
2034
2035         if (current_is_pdflush() || current->flags & PF_MEMALLOC)
2036                 return;
2037
2038         num_dirty = count_range_bits(tree, &start, (u64)-1,
2039                                      thresh, EXTENT_DIRTY);
2040         if (num_dirty > thresh) {
2041                 balance_dirty_pages_ratelimited_nr(
2042                                    root->fs_info->btree_inode->i_mapping, 1);
2043         }
2044         return;
2045 }
2046
2047 int btrfs_read_buffer(struct extent_buffer *buf, u64 parent_transid)
2048 {
2049         struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;
2050         int ret;
2051         ret = btree_read_extent_buffer_pages(root, buf, 0, parent_transid);
2052         if (ret == 0) {
2053                 buf->flags |= EXTENT_UPTODATE;
2054         }
2055         return ret;
2056 }
2057
2058 int btree_lock_page_hook(struct page *page)
2059 {
2060         struct inode *inode = page->mapping->host;
2061         struct btrfs_root *root = BTRFS_I(inode)->root;
2062         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
2063         struct extent_buffer *eb;
2064         unsigned long len;
2065         u64 bytenr = page_offset(page);
2066
2067         if (page->private == EXTENT_PAGE_PRIVATE)
2068                 goto out;
2069
2070         len = page->private >> 2;
2071         eb = find_extent_buffer(io_tree, bytenr, len, GFP_NOFS);
2072         if (!eb)
2073                 goto out;
2074
2075         btrfs_tree_lock(eb);
2076         spin_lock(&root->fs_info->hash_lock);
2077         btrfs_set_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN);
2078         spin_unlock(&root->fs_info->hash_lock);
2079         btrfs_tree_unlock(eb);
2080         free_extent_buffer(eb);
2081 out:
2082         lock_page(page);
2083         return 0;
2084 }
2085
2086 static struct extent_io_ops btree_extent_io_ops = {
2087         .write_cache_pages_lock_hook = btree_lock_page_hook,
2088         .readpage_end_io_hook = btree_readpage_end_io_hook,
2089         .submit_bio_hook = btree_submit_bio_hook,
2090         /* note we're sharing with inode.c for the merge bio hook */
2091         .merge_bio_hook = btrfs_merge_bio_hook,
2092 };