Pileus Git - ~andy/linux/blob - fs/btrfs/transaction.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/fs.h>
  20 #include <linux/sched.h>
  21 #include <linux/writeback.h>
  22 #include <linux/pagemap.h>
  23 #include "ctree.h"
  24 #include "disk-io.h"
  25 #include "transaction.h"
  26 #include "locking.h"
  27
  28 static int total_trans = 0;
  29 extern struct kmem_cache *btrfs_trans_handle_cachep;
  30 extern struct kmem_cache *btrfs_transaction_cachep;
  31
  32 #define BTRFS_ROOT_TRANS_TAG 0
  33
  34 static noinline void put_transaction(struct btrfs_transaction *transaction)
  35 {
  36         WARN_ON(transaction->use_count == 0);
  37         transaction->use_count--;
  38         if (transaction->use_count == 0) {
  39                 WARN_ON(total_trans == 0);
  40                 total_trans--;
  41                 list_del_init(&transaction->list);
  42                 memset(transaction, 0, sizeof(*transaction));
  43                 kmem_cache_free(btrfs_transaction_cachep, transaction);
  44         }
  45 }
  46
  47 static noinline int join_transaction(struct btrfs_root *root)
  48 {
  49         struct btrfs_transaction *cur_trans;
  50         cur_trans = root->fs_info->running_transaction;
  51         if (!cur_trans) {
  52                 cur_trans = kmem_cache_alloc(btrfs_transaction_cachep,
  53                                              GFP_NOFS);
  54                 total_trans++;
  55                 BUG_ON(!cur_trans);
  56                 root->fs_info->generation++;
  57                 root->fs_info->last_alloc = 0;
  58                 root->fs_info->last_data_alloc = 0;
  59                 cur_trans->num_writers = 1;
  60                 cur_trans->num_joined = 0;
  61                 cur_trans->transid = root->fs_info->generation;
  62                 init_waitqueue_head(&cur_trans->writer_wait);
  63                 init_waitqueue_head(&cur_trans->commit_wait);
  64                 cur_trans->in_commit = 0;
  65                 cur_trans->blocked = 0;
  66                 cur_trans->use_count = 1;
  67                 cur_trans->commit_done = 0;
  68                 cur_trans->start_time = get_seconds();
  69                 INIT_LIST_HEAD(&cur_trans->pending_snapshots);
  70                 list_add_tail(&cur_trans->list, &root->fs_info->trans_list);
  71                 extent_io_tree_init(&cur_trans->dirty_pages,
  72                                      root->fs_info->btree_inode->i_mapping,
  73                                      GFP_NOFS);
  74                 spin_lock(&root->fs_info->new_trans_lock);
  75                 root->fs_info->running_transaction = cur_trans;
  76                 spin_unlock(&root->fs_info->new_trans_lock);
  77         } else {
  78                 cur_trans->num_writers++;
  79                 cur_trans->num_joined++;
  80         }
  81
  82         return 0;
  83 }
  84
  85 static noinline int record_root_in_trans(struct btrfs_root *root)
  86 {
  87         u64 running_trans_id = root->fs_info->running_transaction->transid;
  88         if (root->ref_cows && root->last_trans < running_trans_id) {
  89                 WARN_ON(root == root->fs_info->extent_root);
  90                 if (root->root_item.refs != 0) {
  91                         radix_tree_tag_set(&root->fs_info->fs_roots_radix,
  92                                    (unsigned long)root->root_key.objectid,
  93                                    BTRFS_ROOT_TRANS_TAG);
  94                         root->commit_root = btrfs_root_node(root);
  95                 } else {
  96                         WARN_ON(1);
  97                 }
  98                 root->last_trans = running_trans_id;
  99         }
 100         return 0;
 101 }
 102
 103 struct btrfs_trans_handle *start_transaction(struct btrfs_root *root,
 104                                              int num_blocks, int join)
 105 {
 106         struct btrfs_trans_handle *h =
 107                 kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS);
 108         struct btrfs_transaction *cur_trans;
 109         int ret;
 110
 111         mutex_lock(&root->fs_info->trans_mutex);
 112         cur_trans = root->fs_info->running_transaction;
 113         if (cur_trans && cur_trans->blocked && !join) {
 114                 DEFINE_WAIT(wait);
 115                 cur_trans->use_count++;
 116                 while(1) {
 117                         prepare_to_wait(&root->fs_info->transaction_wait, &wait,
 118                                         TASK_UNINTERRUPTIBLE);
 119                         if (cur_trans->blocked) {
 120                                 mutex_unlock(&root->fs_info->trans_mutex);
 121                                 schedule();
 122                                 mutex_lock(&root->fs_info->trans_mutex);
 123                                 finish_wait(&root->fs_info->transaction_wait,
 124                                             &wait);
 125                         } else {
 126                                 finish_wait(&root->fs_info->transaction_wait,
 127                                             &wait);
 128                                 break;
 129                         }
 130                 }
 131                 put_transaction(cur_trans);
 132         }
 133         ret = join_transaction(root);
 134         BUG_ON(ret);
 135
 136         record_root_in_trans(root);
 137         h->transid = root->fs_info->running_transaction->transid;
 138         h->transaction = root->fs_info->running_transaction;
 139         h->blocks_reserved = num_blocks;
 140         h->blocks_used = 0;
 141         h->block_group = NULL;
 142         h->alloc_exclude_nr = 0;
 143         h->alloc_exclude_start = 0;
 144         root->fs_info->running_transaction->use_count++;
 145         mutex_unlock(&root->fs_info->trans_mutex);
 146         return h;
 147 }
 148
 149 struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
 150                                                    int num_blocks)
 151 {
 152         return start_transaction(root, num_blocks, 0);
 153 }
 154 struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root,
 155                                                    int num_blocks)
 156 {
 157         return start_transaction(root, num_blocks, 1);
 158 }
 159
 160 static noinline int wait_for_commit(struct btrfs_root *root,
 161                                     struct btrfs_transaction *commit)
 162 {
 163         DEFINE_WAIT(wait);
 164         mutex_lock(&root->fs_info->trans_mutex);
 165         while(!commit->commit_done) {
 166                 prepare_to_wait(&commit->commit_wait, &wait,
 167                                 TASK_UNINTERRUPTIBLE);
 168                 if (commit->commit_done)
 169                         break;
 170                 mutex_unlock(&root->fs_info->trans_mutex);
 171                 schedule();
 172                 mutex_lock(&root->fs_info->trans_mutex);
 173         }
 174         mutex_unlock(&root->fs_info->trans_mutex);
 175         finish_wait(&commit->commit_wait, &wait);
 176         return 0;
 177 }
 178
 179 static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
 180                           struct btrfs_root *root, int throttle)
 181 {
 182         struct btrfs_transaction *cur_trans;
 183
 184         mutex_lock(&root->fs_info->trans_mutex);
 185         cur_trans = root->fs_info->running_transaction;
 186         WARN_ON(cur_trans != trans->transaction);
 187         WARN_ON(cur_trans->num_writers < 1);
 188         cur_trans->num_writers--;
 189
 190         if (waitqueue_active(&cur_trans->writer_wait))
 191                 wake_up(&cur_trans->writer_wait);
 192
 193         if (0 && cur_trans->in_commit && throttle) {
 194                 DEFINE_WAIT(wait);
 195                 mutex_unlock(&root->fs_info->trans_mutex);
 196                 prepare_to_wait(&root->fs_info->transaction_throttle, &wait,
 197                                 TASK_UNINTERRUPTIBLE);
 198                 schedule();
 199                 finish_wait(&root->fs_info->transaction_throttle, &wait);
 200                 mutex_lock(&root->fs_info->trans_mutex);
 201         }
 202
 203         put_transaction(cur_trans);
 204         mutex_unlock(&root->fs_info->trans_mutex);
 205         memset(trans, 0, sizeof(*trans));
 206         kmem_cache_free(btrfs_trans_handle_cachep, trans);
 207         return 0;
 208 }
 209
 210 int btrfs_end_transaction(struct btrfs_trans_handle *trans,
 211                           struct btrfs_root *root)
 212 {
 213         return __btrfs_end_transaction(trans, root, 0);
 214 }
 215
 216 int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans,
 217                                    struct btrfs_root *root)
 218 {
 219         return __btrfs_end_transaction(trans, root, 1);
 220 }
 221
 222
 223 int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans,
 224                                      struct btrfs_root *root)
 225 {
 226         int ret;
 227         int err;
 228         int werr = 0;
 229         struct extent_io_tree *dirty_pages;
 230         struct page *page;
 231         struct inode *btree_inode = root->fs_info->btree_inode;
 232         u64 start;
 233         u64 end;
 234         unsigned long index;
 235
 236         if (!trans || !trans->transaction) {
 237                 return filemap_write_and_wait(btree_inode->i_mapping);
 238         }
 239         dirty_pages = &trans->transaction->dirty_pages;
 240         while(1) {
 241                 ret = find_first_extent_bit(dirty_pages, 0, &start, &end,
 242                                             EXTENT_DIRTY);
 243                 if (ret)
 244                         break;
 245                 clear_extent_dirty(dirty_pages, start, end, GFP_NOFS);
 246                 while(start <= end) {
 247                         index = start >> PAGE_CACHE_SHIFT;
 248                         start = (u64)(index + 1) << PAGE_CACHE_SHIFT;
 249                         page = find_lock_page(btree_inode->i_mapping, index);
 250                         if (!page)
 251                                 continue;
 252                         if (PageWriteback(page)) {
 253                                 if (PageDirty(page))
 254                                         wait_on_page_writeback(page);
 255                                 else {
 256                                         unlock_page(page);
 257                                         page_cache_release(page);
 258                                         continue;
 259                                 }
 260                         }
 261                         err = write_one_page(page, 0);
 262                         if (err)
 263                                 werr = err;
 264                         page_cache_release(page);
 265                 }
 266         }
 267         err = filemap_fdatawait(btree_inode->i_mapping);
 268         if (err)
 269                 werr = err;
 270         return werr;
 271 }
 272
 273 static int update_cowonly_root(struct btrfs_trans_handle *trans,
 274                                struct btrfs_root *root)
 275 {
 276         int ret;
 277         u64 old_root_bytenr;
 278         struct btrfs_root *tree_root = root->fs_info->tree_root;
 279
 280         btrfs_write_dirty_block_groups(trans, root);
 281         while(1) {
 282                 old_root_bytenr = btrfs_root_bytenr(&root->root_item);
 283                 if (old_root_bytenr == root->node->start)
 284                         break;
 285                 btrfs_set_root_bytenr(&root->root_item,
 286                                        root->node->start);
 287                 btrfs_set_root_level(&root->root_item,
 288                                      btrfs_header_level(root->node));
 289                 ret = btrfs_update_root(trans, tree_root,
 290                                         &root->root_key,
 291                                         &root->root_item);
 292                 BUG_ON(ret);
 293                 btrfs_write_dirty_block_groups(trans, root);
 294         }
 295         return 0;
 296 }
 297
 298 int btrfs_commit_tree_roots(struct btrfs_trans_handle *trans,
 299                             struct btrfs_root *root)
 300 {
 301         struct btrfs_fs_info *fs_info = root->fs_info;
 302         struct list_head *next;
 303
 304         while(!list_empty(&fs_info->dirty_cowonly_roots)) {
 305                 next = fs_info->dirty_cowonly_roots.next;
 306                 list_del_init(next);
 307                 root = list_entry(next, struct btrfs_root, dirty_list);
 308                 update_cowonly_root(trans, root);
 309         }
 310         return 0;
 311 }
 312
 313 struct dirty_root {
 314         struct list_head list;
 315         struct btrfs_root *root;
 316         struct btrfs_root *latest_root;
 317 };
 318
 319 int btrfs_add_dead_root(struct btrfs_root *root,
 320                         struct btrfs_root *latest,
 321                         struct list_head *dead_list)
 322 {
 323         struct dirty_root *dirty;
 324
 325         dirty = kmalloc(sizeof(*dirty), GFP_NOFS);
 326         if (!dirty)
 327                 return -ENOMEM;
 328         dirty->root = root;
 329         dirty->latest_root = latest;
 330         list_add(&dirty->list, dead_list);
 331         return 0;
 332 }
 333
 334 static noinline int add_dirty_roots(struct btrfs_trans_handle *trans,
 335                                     struct radix_tree_root *radix,
 336                                     struct list_head *list)
 337 {
 338         struct dirty_root *dirty;
 339         struct btrfs_root *gang[8];
 340         struct btrfs_root *root;
 341         int i;
 342         int ret;
 343         int err = 0;
 344         u32 refs;
 345
 346         while(1) {
 347                 ret = radix_tree_gang_lookup_tag(radix, (void **)gang, 0,
 348                                                  ARRAY_SIZE(gang),
 349                                                  BTRFS_ROOT_TRANS_TAG);
 350                 if (ret == 0)
 351                         break;
 352                 for (i = 0; i < ret; i++) {
 353                         root = gang[i];
 354                         radix_tree_tag_clear(radix,
 355                                      (unsigned long)root->root_key.objectid,
 356                                      BTRFS_ROOT_TRANS_TAG);
 357                         if (root->commit_root == root->node) {
 358                                 WARN_ON(root->node->start !=
 359                                         btrfs_root_bytenr(&root->root_item));
 360                                 free_extent_buffer(root->commit_root);
 361                                 root->commit_root = NULL;
 362
 363                                 /* make sure to update the root on disk
 364                                  * so we get any updates to the block used
 365                                  * counts
 366                                  */
 367                                 err = btrfs_update_root(trans,
 368                                                 root->fs_info->tree_root,
 369                                                 &root->root_key,
 370                                                 &root->root_item);
 371                                 continue;
 372                         }
 373                         dirty = kmalloc(sizeof(*dirty), GFP_NOFS);
 374                         BUG_ON(!dirty);
 375                         dirty->root = kmalloc(sizeof(*dirty->root), GFP_NOFS);
 376                         BUG_ON(!dirty->root);
 377
 378                         memset(&root->root_item.drop_progress, 0,
 379                                sizeof(struct btrfs_disk_key));
 380                         root->root_item.drop_level = 0;
 381
 382                         memcpy(dirty->root, root, sizeof(*root));
 383                         dirty->root->node = root->commit_root;
 384                         dirty->latest_root = root;
 385                         root->commit_root = NULL;
 386
 387                         root->root_key.offset = root->fs_info->generation;
 388                         btrfs_set_root_bytenr(&root->root_item,
 389                                               root->node->start);
 390                         btrfs_set_root_level(&root->root_item,
 391                                              btrfs_header_level(root->node));
 392                         err = btrfs_insert_root(trans, root->fs_info->tree_root,
 393                                                 &root->root_key,
 394                                                 &root->root_item);
 395                         if (err)
 396                                 break;
 397
 398                         refs = btrfs_root_refs(&dirty->root->root_item);
 399                         btrfs_set_root_refs(&dirty->root->root_item, refs - 1);
 400                         err = btrfs_update_root(trans, root->fs_info->tree_root,
 401                                                 &dirty->root->root_key,
 402                                                 &dirty->root->root_item);
 403
 404                         BUG_ON(err);
 405                         if (refs == 1) {
 406                                 list_add(&dirty->list, list);
 407                         } else {
 408                                 WARN_ON(1);
 409                                 kfree(dirty->root);
 410                                 kfree(dirty);
 411                         }
 412                 }
 413         }
 414         return err;
 415 }
 416
 417 int btrfs_defrag_root(struct btrfs_root *root, int cacheonly)
 418 {
 419         struct btrfs_fs_info *info = root->fs_info;
 420         int ret;
 421         struct btrfs_trans_handle *trans;
 422         unsigned long nr;
 423
 424         smp_mb();
 425         if (root->defrag_running)
 426                 return 0;
 427         trans = btrfs_start_transaction(root, 1);
 428         while (1) {
 429                 root->defrag_running = 1;
 430                 ret = btrfs_defrag_leaves(trans, root, cacheonly);
 431                 nr = trans->blocks_used;
 432                 btrfs_end_transaction(trans, root);
 433                 btrfs_btree_balance_dirty(info->tree_root, nr);
 434                 cond_resched();
 435
 436                 trans = btrfs_start_transaction(root, 1);
 437                 if (root->fs_info->closing || ret != -EAGAIN)
 438                         break;
 439         }
 440         root->defrag_running = 0;
 441         smp_mb();
 442         btrfs_end_transaction(trans, root);
 443         return 0;
 444 }
 445
 446 static noinline int drop_dirty_roots(struct btrfs_root *tree_root,
 447                                      struct list_head *list)
 448 {
 449         struct dirty_root *dirty;
 450         struct btrfs_trans_handle *trans;
 451         unsigned long nr;
 452         u64 num_bytes;
 453         u64 bytes_used;
 454         int ret = 0;
 455         int err;
 456
 457         while(!list_empty(list)) {
 458                 struct btrfs_root *root;
 459
 460                 dirty = list_entry(list->next, struct dirty_root, list);
 461                 list_del_init(&dirty->list);
 462
 463                 num_bytes = btrfs_root_used(&dirty->root->root_item);
 464                 root = dirty->latest_root;
 465                 atomic_inc(&root->fs_info->throttles);
 466
 467                 mutex_lock(&root->fs_info->drop_mutex);
 468                 while(1) {
 469                         trans = btrfs_start_transaction(tree_root, 1);
 470                         ret = btrfs_drop_snapshot(trans, dirty->root);
 471                         if (ret != -EAGAIN) {
 472                                 break;
 473                         }
 474
 475                         err = btrfs_update_root(trans,
 476                                         tree_root,
 477                                         &dirty->root->root_key,
 478                                         &dirty->root->root_item);
 479                         if (err)
 480                                 ret = err;
 481                         nr = trans->blocks_used;
 482                         ret = btrfs_end_transaction_throttle(trans, tree_root);
 483                         BUG_ON(ret);
 484
 485                         mutex_unlock(&root->fs_info->drop_mutex);
 486                         btrfs_btree_balance_dirty(tree_root, nr);
 487                         cond_resched();
 488                         mutex_lock(&root->fs_info->drop_mutex);
 489                 }
 490                 BUG_ON(ret);
 491                 atomic_dec(&root->fs_info->throttles);
 492
 493                 mutex_lock(&root->fs_info->alloc_mutex);
 494                 num_bytes -= btrfs_root_used(&dirty->root->root_item);
 495                 bytes_used = btrfs_root_used(&root->root_item);
 496                 if (num_bytes) {
 497                         record_root_in_trans(root);
 498                         btrfs_set_root_used(&root->root_item,
 499                                             bytes_used - num_bytes);
 500                 }
 501                 mutex_unlock(&root->fs_info->alloc_mutex);
 502
 503                 ret = btrfs_del_root(trans, tree_root, &dirty->root->root_key);
 504                 if (ret) {
 505                         BUG();
 506                         break;
 507                 }
 508                 mutex_unlock(&root->fs_info->drop_mutex);
 509
 510                 nr = trans->blocks_used;
 511                 ret = btrfs_end_transaction(trans, tree_root);
 512                 BUG_ON(ret);
 513
 514                 free_extent_buffer(dirty->root->node);
 515                 kfree(dirty->root);
 516                 kfree(dirty);
 517
 518                 btrfs_btree_balance_dirty(tree_root, nr);
 519                 cond_resched();
 520         }
 521         return ret;
 522 }
 523
 524 static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
 525                                    struct btrfs_fs_info *fs_info,
 526                                    struct btrfs_pending_snapshot *pending)
 527 {
 528         struct btrfs_key key;
 529         struct btrfs_root_item *new_root_item;
 530         struct btrfs_root *tree_root = fs_info->tree_root;
 531         struct btrfs_root *root = pending->root;
 532         struct extent_buffer *tmp;
 533         struct extent_buffer *old;
 534         int ret;
 535         int namelen;
 536         u64 objectid;
 537
 538         new_root_item = kmalloc(sizeof(*new_root_item), GFP_NOFS);
 539         if (!new_root_item) {
 540                 ret = -ENOMEM;
 541                 goto fail;
 542         }
 543         ret = btrfs_find_free_objectid(trans, tree_root, 0, &objectid);
 544         if (ret)
 545                 goto fail;
 546
 547         memcpy(new_root_item, &root->root_item, sizeof(*new_root_item));
 548
 549         key.objectid = objectid;
 550         key.offset = 1;
 551         btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
 552
 553         old = btrfs_lock_root_node(root);
 554         btrfs_cow_block(trans, root, old, NULL, 0, &old);
 555
 556         btrfs_copy_root(trans, root, old, &tmp, objectid);
 557         btrfs_tree_unlock(old);
 558         free_extent_buffer(old);
 559
 560         btrfs_set_root_bytenr(new_root_item, tmp->start);
 561         btrfs_set_root_level(new_root_item, btrfs_header_level(tmp));
 562         ret = btrfs_insert_root(trans, root->fs_info->tree_root, &key,
 563                                 new_root_item);
 564         btrfs_tree_unlock(tmp);
 565         free_extent_buffer(tmp);
 566         if (ret)
 567                 goto fail;
 568
 569         /*
 570          * insert the directory item
 571          */
 572         key.offset = (u64)-1;
 573         namelen = strlen(pending->name);
 574         ret = btrfs_insert_dir_item(trans, root->fs_info->tree_root,
 575                                     pending->name, namelen,
 576                                     root->fs_info->sb->s_root->d_inode->i_ino,
 577                                     &key, BTRFS_FT_DIR);
 578
 579         if (ret)
 580                 goto fail;
 581
 582         ret = btrfs_insert_inode_ref(trans, root->fs_info->tree_root,
 583                              pending->name, strlen(pending->name), objectid,
 584                              root->fs_info->sb->s_root->d_inode->i_ino);
 585
 586         /* Invalidate existing dcache entry for new snapshot. */
 587         btrfs_invalidate_dcache_root(root, pending->name, namelen);
 588
 589 fail:
 590         kfree(new_root_item);
 591         return ret;
 592 }
 593
 594 static noinline int create_pending_snapshots(struct btrfs_trans_handle *trans,
 595                                              struct btrfs_fs_info *fs_info)
 596 {
 597         struct btrfs_pending_snapshot *pending;
 598         struct list_head *head = &trans->transaction->pending_snapshots;
 599         int ret;
 600
 601         while(!list_empty(head)) {
 602                 pending = list_entry(head->next,
 603                                      struct btrfs_pending_snapshot, list);
 604                 ret = create_pending_snapshot(trans, fs_info, pending);
 605                 BUG_ON(ret);
 606                 list_del(&pending->list);
 607                 kfree(pending->name);
 608                 kfree(pending);
 609         }
 610         return 0;
 611 }
 612
 613 int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
 614                              struct btrfs_root *root)
 615 {
 616         unsigned long joined = 0;
 617         unsigned long timeout = 1;
 618         struct btrfs_transaction *cur_trans;
 619         struct btrfs_transaction *prev_trans = NULL;
 620         struct btrfs_root *chunk_root = root->fs_info->chunk_root;
 621         struct list_head dirty_fs_roots;
 622         struct extent_io_tree *pinned_copy;
 623         DEFINE_WAIT(wait);
 624         int ret;
 625
 626         INIT_LIST_HEAD(&dirty_fs_roots);
 627
 628         mutex_lock(&root->fs_info->trans_mutex);
 629         if (trans->transaction->in_commit) {
 630                 cur_trans = trans->transaction;
 631                 trans->transaction->use_count++;
 632                 mutex_unlock(&root->fs_info->trans_mutex);
 633                 btrfs_end_transaction(trans, root);
 634
 635                 ret = wait_for_commit(root, cur_trans);
 636                 BUG_ON(ret);
 637
 638                 mutex_lock(&root->fs_info->trans_mutex);
 639                 put_transaction(cur_trans);
 640                 mutex_unlock(&root->fs_info->trans_mutex);
 641
 642                 return 0;
 643         }
 644
 645         pinned_copy = kmalloc(sizeof(*pinned_copy), GFP_NOFS);
 646         if (!pinned_copy)
 647                 return -ENOMEM;
 648
 649         extent_io_tree_init(pinned_copy,
 650                              root->fs_info->btree_inode->i_mapping, GFP_NOFS);
 651
 652 printk("commit trans %Lu\n", trans->transid);
 653         trans->transaction->in_commit = 1;
 654         trans->transaction->blocked = 1;
 655         cur_trans = trans->transaction;
 656         if (cur_trans->list.prev != &root->fs_info->trans_list) {
 657                 prev_trans = list_entry(cur_trans->list.prev,
 658                                         struct btrfs_transaction, list);
 659                 if (!prev_trans->commit_done) {
 660                         prev_trans->use_count++;
 661                         mutex_unlock(&root->fs_info->trans_mutex);
 662
 663                         wait_for_commit(root, prev_trans);
 664
 665                         mutex_lock(&root->fs_info->trans_mutex);
 666                         put_transaction(prev_trans);
 667                 }
 668         }
 669
 670         do {
 671                 joined = cur_trans->num_joined;
 672                 WARN_ON(cur_trans != trans->transaction);
 673                 prepare_to_wait(&cur_trans->writer_wait, &wait,
 674                                 TASK_UNINTERRUPTIBLE);
 675
 676                 if (cur_trans->num_writers > 1)
 677                         timeout = MAX_SCHEDULE_TIMEOUT;
 678                 else
 679                         timeout = 1;
 680
 681                 mutex_unlock(&root->fs_info->trans_mutex);
 682
 683                 schedule_timeout(timeout);
 684
 685                 mutex_lock(&root->fs_info->trans_mutex);
 686                 finish_wait(&cur_trans->writer_wait, &wait);
 687         } while (cur_trans->num_writers > 1 ||
 688                  (cur_trans->num_joined != joined));
 689
 690         ret = create_pending_snapshots(trans, root->fs_info);
 691         BUG_ON(ret);
 692
 693         WARN_ON(cur_trans != trans->transaction);
 694
 695         ret = add_dirty_roots(trans, &root->fs_info->fs_roots_radix,
 696                               &dirty_fs_roots);
 697         BUG_ON(ret);
 698
 699         ret = btrfs_commit_tree_roots(trans, root);
 700         BUG_ON(ret);
 701
 702         cur_trans = root->fs_info->running_transaction;
 703         spin_lock(&root->fs_info->new_trans_lock);
 704         root->fs_info->running_transaction = NULL;
 705         spin_unlock(&root->fs_info->new_trans_lock);
 706         btrfs_set_super_generation(&root->fs_info->super_copy,
 707                                    cur_trans->transid);
 708         btrfs_set_super_root(&root->fs_info->super_copy,
 709                              root->fs_info->tree_root->node->start);
 710         btrfs_set_super_root_level(&root->fs_info->super_copy,
 711                            btrfs_header_level(root->fs_info->tree_root->node));
 712
 713         btrfs_set_super_chunk_root(&root->fs_info->super_copy,
 714                                    chunk_root->node->start);
 715         btrfs_set_super_chunk_root_level(&root->fs_info->super_copy,
 716                                          btrfs_header_level(chunk_root->node));
 717         memcpy(&root->fs_info->super_for_commit, &root->fs_info->super_copy,
 718                sizeof(root->fs_info->super_copy));
 719
 720         btrfs_copy_pinned(root, pinned_copy);
 721
 722         trans->transaction->blocked = 0;
 723         wake_up(&root->fs_info->transaction_throttle);
 724         wake_up(&root->fs_info->transaction_wait);
 725
 726         mutex_unlock(&root->fs_info->trans_mutex);
 727         ret = btrfs_write_and_wait_transaction(trans, root);
 728         BUG_ON(ret);
 729         write_ctree_super(trans, root);
 730
 731         btrfs_finish_extent_commit(trans, root, pinned_copy);
 732         mutex_lock(&root->fs_info->trans_mutex);
 733
 734         kfree(pinned_copy);
 735
 736         cur_trans->commit_done = 1;
 737         root->fs_info->last_trans_committed = cur_trans->transid;
 738         wake_up(&cur_trans->commit_wait);
 739         put_transaction(cur_trans);
 740         put_transaction(cur_trans);
 741
 742         if (root->fs_info->closing)
 743                 list_splice_init(&root->fs_info->dead_roots, &dirty_fs_roots);
 744         else
 745                 list_splice_init(&dirty_fs_roots, &root->fs_info->dead_roots);
 746
 747         mutex_unlock(&root->fs_info->trans_mutex);
 748 printk("done commit trans %Lu\n", trans->transid);
 749         kmem_cache_free(btrfs_trans_handle_cachep, trans);
 750
 751         if (root->fs_info->closing) {
 752                 drop_dirty_roots(root->fs_info->tree_root, &dirty_fs_roots);
 753         }
 754         return ret;
 755 }
 756
 757 int btrfs_clean_old_snapshots(struct btrfs_root *root)
 758 {
 759         struct list_head dirty_roots;
 760         INIT_LIST_HEAD(&dirty_roots);
 761 again:
 762         mutex_lock(&root->fs_info->trans_mutex);
 763         list_splice_init(&root->fs_info->dead_roots, &dirty_roots);
 764         mutex_unlock(&root->fs_info->trans_mutex);
 765
 766         if (!list_empty(&dirty_roots)) {
 767                 drop_dirty_roots(root, &dirty_roots);
 768                 goto again;
 769         }
 770         return 0;
 771 }
 772