git.oblomov.eu Git - linux-2.6/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
  27 static int total_trans = 0;
  28 extern struct kmem_cache *btrfs_trans_handle_cachep;
  29 extern struct kmem_cache *btrfs_transaction_cachep;
  30
  31 static struct workqueue_struct *trans_wq;
  32
  33 #define BTRFS_ROOT_TRANS_TAG 0
  34 #define BTRFS_ROOT_DEFRAG_TAG 1
  35
  36 static void put_transaction(struct btrfs_transaction *transaction)
  37 {
  38         WARN_ON(transaction->use_count == 0);
  39         transaction->use_count--;
  40         if (transaction->use_count == 0) {
  41                 WARN_ON(total_trans == 0);
  42                 total_trans--;
  43                 list_del_init(&transaction->list);
  44                 memset(transaction, 0, sizeof(*transaction));
  45                 kmem_cache_free(btrfs_transaction_cachep, transaction);
  46         }
  47 }
  48
  49 static int join_transaction(struct btrfs_root *root)
  50 {
  51         struct btrfs_transaction *cur_trans;
  52         cur_trans = root->fs_info->running_transaction;
  53         if (!cur_trans) {
  54                 cur_trans = kmem_cache_alloc(btrfs_transaction_cachep,
  55                                              GFP_NOFS);
  56                 total_trans++;
  57                 BUG_ON(!cur_trans);
  58                 root->fs_info->generation++;
  59                 root->fs_info->running_transaction = cur_trans;
  60                 cur_trans->num_writers = 1;
  61                 cur_trans->num_joined = 0;
  62                 cur_trans->transid = root->fs_info->generation;
  63                 init_waitqueue_head(&cur_trans->writer_wait);
  64                 init_waitqueue_head(&cur_trans->commit_wait);
  65                 cur_trans->in_commit = 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                 btrfs_ordered_inode_tree_init(&cur_trans->ordered_inode_tree);
  72                 extent_map_tree_init(&cur_trans->dirty_pages,
  73                                      root->fs_info->btree_inode->i_mapping,
  74                                      GFP_NOFS);
  75         } else {
  76                 cur_trans->num_writers++;
  77                 cur_trans->num_joined++;
  78         }
  79
  80         return 0;
  81 }
  82
  83 static int record_root_in_trans(struct btrfs_root *root)
  84 {
  85         u64 running_trans_id = root->fs_info->running_transaction->transid;
  86         if (root->ref_cows && root->last_trans < running_trans_id) {
  87                 WARN_ON(root == root->fs_info->extent_root);
  88                 if (root->root_item.refs != 0) {
  89                         radix_tree_tag_set(&root->fs_info->fs_roots_radix,
  90                                    (unsigned long)root->root_key.objectid,
  91                                    BTRFS_ROOT_TRANS_TAG);
  92                         radix_tree_tag_set(&root->fs_info->fs_roots_radix,
  93                                    (unsigned long)root->root_key.objectid,
  94                                    BTRFS_ROOT_DEFRAG_TAG);
  95                         root->commit_root = root->node;
  96                         extent_buffer_get(root->node);
  97                 } else {
  98                         WARN_ON(1);
  99                 }
 100                 root->last_trans = running_trans_id;
 101         }
 102         return 0;
 103 }
 104
 105 struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
 106                                                    int num_blocks)
 107 {
 108         struct btrfs_trans_handle *h =
 109                 kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS);
 110         int ret;
 111
 112         mutex_lock(&root->fs_info->trans_mutex);
 113         ret = join_transaction(root);
 114         BUG_ON(ret);
 115
 116         record_root_in_trans(root);
 117         h->transid = root->fs_info->running_transaction->transid;
 118         h->transaction = root->fs_info->running_transaction;
 119         h->blocks_reserved = num_blocks;
 120         h->blocks_used = 0;
 121         h->block_group = NULL;
 122         h->alloc_exclude_nr = 0;
 123         h->alloc_exclude_start = 0;
 124         root->fs_info->running_transaction->use_count++;
 125         mutex_unlock(&root->fs_info->trans_mutex);
 126         return h;
 127 }
 128
 129 int btrfs_end_transaction(struct btrfs_trans_handle *trans,
 130                           struct btrfs_root *root)
 131 {
 132         struct btrfs_transaction *cur_trans;
 133
 134         mutex_lock(&root->fs_info->trans_mutex);
 135         cur_trans = root->fs_info->running_transaction;
 136         WARN_ON(cur_trans != trans->transaction);
 137         WARN_ON(cur_trans->num_writers < 1);
 138         cur_trans->num_writers--;
 139         if (waitqueue_active(&cur_trans->writer_wait))
 140                 wake_up(&cur_trans->writer_wait);
 141         put_transaction(cur_trans);
 142         mutex_unlock(&root->fs_info->trans_mutex);
 143         memset(trans, 0, sizeof(*trans));
 144         kmem_cache_free(btrfs_trans_handle_cachep, trans);
 145         return 0;
 146 }
 147
 148
 149 int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans,
 150                                      struct btrfs_root *root)
 151 {
 152         int ret;
 153         int err;
 154         int werr = 0;
 155         struct extent_map_tree *dirty_pages;
 156         struct page *page;
 157         struct inode *btree_inode = root->fs_info->btree_inode;
 158         u64 start;
 159         u64 end;
 160         unsigned long index;
 161
 162         if (!trans || !trans->transaction) {
 163                 return filemap_write_and_wait(btree_inode->i_mapping);
 164         }
 165         dirty_pages = &trans->transaction->dirty_pages;
 166         while(1) {
 167                 ret = find_first_extent_bit(dirty_pages, 0, &start, &end,
 168                                             EXTENT_DIRTY);
 169                 if (ret)
 170                         break;
 171                 clear_extent_dirty(dirty_pages, start, end, GFP_NOFS);
 172                 while(start <= end) {
 173                         index = start >> PAGE_CACHE_SHIFT;
 174                         start = (u64)(index + 1) << PAGE_CACHE_SHIFT;
 175                         page = find_lock_page(btree_inode->i_mapping, index);
 176                         if (!page)
 177                                 continue;
 178                         if (PageWriteback(page)) {
 179                                 if (PageDirty(page))
 180                                         wait_on_page_writeback(page);
 181                                 else {
 182                                         unlock_page(page);
 183                                         page_cache_release(page);
 184                                         continue;
 185                                 }
 186                         }
 187                         err = write_one_page(page, 0);
 188                         if (err)
 189                                 werr = err;
 190                         page_cache_release(page);
 191                 }
 192         }
 193         err = filemap_fdatawait(btree_inode->i_mapping);
 194         if (err)
 195                 werr = err;
 196         return werr;
 197 }
 198
 199 int btrfs_commit_tree_roots(struct btrfs_trans_handle *trans,
 200                             struct btrfs_root *root)
 201 {
 202         int ret;
 203         u64 old_extent_block;
 204         struct btrfs_fs_info *fs_info = root->fs_info;
 205         struct btrfs_root *tree_root = fs_info->tree_root;
 206         struct btrfs_root *extent_root = fs_info->extent_root;
 207
 208         btrfs_write_dirty_block_groups(trans, extent_root);
 209         while(1) {
 210                 old_extent_block = btrfs_root_bytenr(&extent_root->root_item);
 211                 if (old_extent_block == extent_root->node->start)
 212                         break;
 213                 btrfs_set_root_bytenr(&extent_root->root_item,
 214                                       extent_root->node->start);
 215                 btrfs_set_root_level(&extent_root->root_item,
 216                                      btrfs_header_level(extent_root->node));
 217                 ret = btrfs_update_root(trans, tree_root,
 218                                         &extent_root->root_key,
 219                                         &extent_root->root_item);
 220                 BUG_ON(ret);
 221                 btrfs_write_dirty_block_groups(trans, extent_root);
 222         }
 223         return 0;
 224 }
 225
 226 static int wait_for_commit(struct btrfs_root *root,
 227                            struct btrfs_transaction *commit)
 228 {
 229         DEFINE_WAIT(wait);
 230         mutex_lock(&root->fs_info->trans_mutex);
 231         while(!commit->commit_done) {
 232                 prepare_to_wait(&commit->commit_wait, &wait,
 233                                 TASK_UNINTERRUPTIBLE);
 234                 if (commit->commit_done)
 235                         break;
 236                 mutex_unlock(&root->fs_info->trans_mutex);
 237                 schedule();
 238                 mutex_lock(&root->fs_info->trans_mutex);
 239         }
 240         mutex_unlock(&root->fs_info->trans_mutex);
 241         finish_wait(&commit->commit_wait, &wait);
 242         return 0;
 243 }
 244
 245 struct dirty_root {
 246         struct list_head list;
 247         struct btrfs_root *root;
 248         struct btrfs_root *latest_root;
 249 };
 250
 251 int btrfs_add_dead_root(struct btrfs_root *root,
 252                         struct btrfs_root *latest,
 253                         struct list_head *dead_list)
 254 {
 255         struct dirty_root *dirty;
 256
 257         dirty = kmalloc(sizeof(*dirty), GFP_NOFS);
 258         if (!dirty)
 259                 return -ENOMEM;
 260         dirty->root = root;
 261         dirty->latest_root = latest;
 262         list_add(&dirty->list, dead_list);
 263         return 0;
 264 }
 265
 266 static int add_dirty_roots(struct btrfs_trans_handle *trans,
 267                            struct radix_tree_root *radix,
 268                            struct list_head *list)
 269 {
 270         struct dirty_root *dirty;
 271         struct btrfs_root *gang[8];
 272         struct btrfs_root *root;
 273         int i;
 274         int ret;
 275         int err = 0;
 276         u32 refs;
 277
 278         while(1) {
 279                 ret = radix_tree_gang_lookup_tag(radix, (void **)gang, 0,
 280                                                  ARRAY_SIZE(gang),
 281                                                  BTRFS_ROOT_TRANS_TAG);
 282                 if (ret == 0)
 283                         break;
 284                 for (i = 0; i < ret; i++) {
 285                         root = gang[i];
 286                         radix_tree_tag_clear(radix,
 287                                      (unsigned long)root->root_key.objectid,
 288                                      BTRFS_ROOT_TRANS_TAG);
 289                         if (root->commit_root == root->node) {
 290                                 WARN_ON(root->node->start !=
 291                                         btrfs_root_bytenr(&root->root_item));
 292                                 free_extent_buffer(root->commit_root);
 293                                 root->commit_root = NULL;
 294
 295                                 /* make sure to update the root on disk
 296                                  * so we get any updates to the block used
 297                                  * counts
 298                                  */
 299                                 err = btrfs_update_root(trans,
 300                                                 root->fs_info->tree_root,
 301                                                 &root->root_key,
 302                                                 &root->root_item);
 303                                 continue;
 304                         }
 305                         dirty = kmalloc(sizeof(*dirty), GFP_NOFS);
 306                         BUG_ON(!dirty);
 307                         dirty->root = kmalloc(sizeof(*dirty->root), GFP_NOFS);
 308                         BUG_ON(!dirty->root);
 309
 310                         memset(&root->root_item.drop_progress, 0,
 311                                sizeof(struct btrfs_disk_key));
 312                         root->root_item.drop_level = 0;
 313
 314                         memcpy(dirty->root, root, sizeof(*root));
 315                         dirty->root->node = root->commit_root;
 316                         dirty->latest_root = root;
 317                         root->commit_root = NULL;
 318
 319                         root->root_key.offset = root->fs_info->generation;
 320                         btrfs_set_root_bytenr(&root->root_item,
 321                                               root->node->start);
 322                         btrfs_set_root_level(&root->root_item,
 323                                              btrfs_header_level(root->node));
 324                         err = btrfs_insert_root(trans, root->fs_info->tree_root,
 325                                                 &root->root_key,
 326                                                 &root->root_item);
 327                         if (err)
 328                                 break;
 329
 330                         refs = btrfs_root_refs(&dirty->root->root_item);
 331                         btrfs_set_root_refs(&dirty->root->root_item, refs - 1);
 332                         err = btrfs_update_root(trans, root->fs_info->tree_root,
 333                                                 &dirty->root->root_key,
 334                                                 &dirty->root->root_item);
 335
 336                         BUG_ON(err);
 337                         if (refs == 1) {
 338                                 list_add(&dirty->list, list);
 339                         } else {
 340                                 WARN_ON(1);
 341                                 kfree(dirty->root);
 342                                 kfree(dirty);
 343                         }
 344                 }
 345         }
 346         return err;
 347 }
 348
 349 int btrfs_defrag_root(struct btrfs_root *root, int cacheonly)
 350 {
 351         struct btrfs_fs_info *info = root->fs_info;
 352         int ret;
 353         struct btrfs_trans_handle *trans;
 354         unsigned long nr;
 355
 356         if (root->defrag_running)
 357                 return 0;
 358         trans = btrfs_start_transaction(root, 1);
 359         while (1) {
 360                 root->defrag_running = 1;
 361                 ret = btrfs_defrag_leaves(trans, root, cacheonly);
 362                 nr = trans->blocks_used;
 363                 btrfs_end_transaction(trans, root);
 364                 mutex_unlock(&info->fs_mutex);
 365                 btrfs_btree_balance_dirty(info->tree_root, nr);
 366                 cond_resched();
 367
 368                 mutex_lock(&info->fs_mutex);
 369                 trans = btrfs_start_transaction(root, 1);
 370                 if (ret != -EAGAIN)
 371                         break;
 372         }
 373         root->defrag_running = 0;
 374         radix_tree_tag_clear(&info->fs_roots_radix,
 375                      (unsigned long)root->root_key.objectid,
 376                      BTRFS_ROOT_DEFRAG_TAG);
 377         btrfs_end_transaction(trans, root);
 378         return 0;
 379 }
 380
 381 int btrfs_defrag_dirty_roots(struct btrfs_fs_info *info)
 382 {
 383         struct btrfs_root *gang[1];
 384         struct btrfs_root *root;
 385         int i;
 386         int ret;
 387         int err = 0;
 388         u64 last = 0;
 389
 390         while(1) {
 391                 ret = radix_tree_gang_lookup_tag(&info->fs_roots_radix,
 392                                                  (void **)gang, last,
 393                                                  ARRAY_SIZE(gang),
 394                                                  BTRFS_ROOT_DEFRAG_TAG);
 395                 if (ret == 0)
 396                         break;
 397                 for (i = 0; i < ret; i++) {
 398                         root = gang[i];
 399                         last = root->root_key.objectid + 1;
 400                         btrfs_defrag_root(root, 1);
 401                 }
 402         }
 403         btrfs_defrag_root(info->extent_root, 1);
 404         return err;
 405 }
 406
 407 static int drop_dirty_roots(struct btrfs_root *tree_root,
 408                             struct list_head *list)
 409 {
 410         struct dirty_root *dirty;
 411         struct btrfs_trans_handle *trans;
 412         unsigned long nr;
 413         u64 num_bytes;
 414         u64 bytes_used;
 415         int ret = 0;
 416         int err;
 417
 418         while(!list_empty(list)) {
 419                 struct btrfs_root *root;
 420
 421                 mutex_lock(&tree_root->fs_info->fs_mutex);
 422                 dirty = list_entry(list->next, struct dirty_root, list);
 423                 list_del_init(&dirty->list);
 424
 425                 num_bytes = btrfs_root_used(&dirty->root->root_item);
 426                 root = dirty->latest_root;
 427                 root->fs_info->throttles++;
 428
 429                 while(1) {
 430                         trans = btrfs_start_transaction(tree_root, 1);
 431                         ret = btrfs_drop_snapshot(trans, dirty->root);
 432                         if (ret != -EAGAIN) {
 433                                 break;
 434                         }
 435
 436                         err = btrfs_update_root(trans,
 437                                         tree_root,
 438                                         &dirty->root->root_key,
 439                                         &dirty->root->root_item);
 440                         if (err)
 441                                 ret = err;
 442                         nr = trans->blocks_used;
 443                         ret = btrfs_end_transaction(trans, tree_root);
 444                         BUG_ON(ret);
 445                         mutex_unlock(&tree_root->fs_info->fs_mutex);
 446                         btrfs_btree_balance_dirty(tree_root, nr);
 447                         cond_resched();
 448                         mutex_lock(&tree_root->fs_info->fs_mutex);
 449                 }
 450                 BUG_ON(ret);
 451                 root->fs_info->throttles--;
 452
 453                 num_bytes -= btrfs_root_used(&dirty->root->root_item);
 454                 bytes_used = btrfs_root_used(&root->root_item);
 455                 if (num_bytes) {
 456                         record_root_in_trans(root);
 457                         btrfs_set_root_used(&root->root_item,
 458                                             bytes_used - num_bytes);
 459                 }
 460                 ret = btrfs_del_root(trans, tree_root, &dirty->root->root_key);
 461                 if (ret) {
 462                         BUG();
 463                         break;
 464                 }
 465                 nr = trans->blocks_used;
 466                 ret = btrfs_end_transaction(trans, tree_root);
 467                 BUG_ON(ret);
 468
 469                 free_extent_buffer(dirty->root->node);
 470                 kfree(dirty->root);
 471                 kfree(dirty);
 472                 mutex_unlock(&tree_root->fs_info->fs_mutex);
 473
 474                 btrfs_btree_balance_dirty(tree_root, nr);
 475                 cond_resched();
 476         }
 477         return ret;
 478 }
 479
 480 int btrfs_write_ordered_inodes(struct btrfs_trans_handle *trans,
 481                                 struct btrfs_root *root)
 482 {
 483         struct btrfs_transaction *cur_trans = trans->transaction;
 484         struct inode *inode;
 485         u64 root_objectid = 0;
 486         u64 objectid = 0;
 487         int ret;
 488
 489         root->fs_info->throttles++;
 490         while(1) {
 491                 ret = btrfs_find_first_ordered_inode(
 492                                 &cur_trans->ordered_inode_tree,
 493                                 &root_objectid, &objectid);
 494                 if (!ret)
 495                         break;
 496
 497                 mutex_unlock(&root->fs_info->trans_mutex);
 498                 mutex_unlock(&root->fs_info->fs_mutex);
 499                 inode = btrfs_ilookup(root->fs_info->sb, objectid,
 500                                       root_objectid);
 501                 if (inode) {
 502                         if (S_ISREG(inode->i_mode))
 503                                 filemap_fdatawrite(inode->i_mapping);
 504                         iput(inode);
 505                 }
 506                 mutex_lock(&root->fs_info->fs_mutex);
 507                 mutex_lock(&root->fs_info->trans_mutex);
 508         }
 509         while(1) {
 510                 root_objectid = 0;
 511                 objectid = 0;
 512                 ret = btrfs_find_del_first_ordered_inode(
 513                                 &cur_trans->ordered_inode_tree,
 514                                 &root_objectid, &objectid);
 515                 if (!ret)
 516                         break;
 517                 mutex_unlock(&root->fs_info->trans_mutex);
 518                 mutex_unlock(&root->fs_info->fs_mutex);
 519                 inode = btrfs_ilookup(root->fs_info->sb, objectid,
 520                                       root_objectid);
 521                 if (inode) {
 522                         if (S_ISREG(inode->i_mode))
 523                                 filemap_write_and_wait(inode->i_mapping);
 524                         atomic_dec(&inode->i_count);
 525                         iput(inode);
 526                 }
 527                 mutex_lock(&root->fs_info->fs_mutex);
 528                 mutex_lock(&root->fs_info->trans_mutex);
 529         }
 530         root->fs_info->throttles--;
 531         return 0;
 532 }
 533
 534 static int create_pending_snapshot(struct btrfs_trans_handle *trans,
 535                                    struct btrfs_fs_info *fs_info,
 536                                    struct btrfs_pending_snapshot *pending)
 537 {
 538         struct btrfs_key key;
 539         struct btrfs_root_item new_root_item;
 540         struct btrfs_root *tree_root = fs_info->tree_root;
 541         struct btrfs_root *root = pending->root;
 542         struct extent_buffer *tmp;
 543         int ret;
 544         u64 objectid;
 545
 546         ret = btrfs_find_free_objectid(trans, tree_root, 0, &objectid);
 547         if (ret)
 548                 goto fail;
 549
 550         memcpy(&new_root_item, &root->root_item, sizeof(new_root_item));
 551
 552         key.objectid = objectid;
 553         key.offset = 1;
 554         btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
 555
 556         extent_buffer_get(root->node);
 557         btrfs_cow_block(trans, root, root->node, NULL, 0, &tmp);
 558         free_extent_buffer(tmp);
 559
 560         btrfs_copy_root(trans, root, root->node, &tmp, objectid);
 561
 562         btrfs_set_root_bytenr(&new_root_item, tmp->start);
 563         btrfs_set_root_level(&new_root_item, btrfs_header_level(tmp));
 564         ret = btrfs_insert_root(trans, root->fs_info->tree_root, &key,
 565                                 &new_root_item);
 566         free_extent_buffer(tmp);
 567         if (ret)
 568                 goto fail;
 569
 570         /*
 571          * insert the directory item
 572          */
 573         key.offset = (u64)-1;
 574         ret = btrfs_insert_dir_item(trans, root->fs_info->tree_root,
 575                                     pending->name, strlen(pending->name),
 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 fail:
 586         return ret;
 587 }
 588
 589 static int create_pending_snapshots(struct btrfs_trans_handle *trans,
 590                                    struct btrfs_fs_info *fs_info)
 591 {
 592         struct btrfs_pending_snapshot *pending;
 593         struct list_head *head = &trans->transaction->pending_snapshots;
 594         int ret;
 595
 596         while(!list_empty(head)) {
 597                 pending = list_entry(head->next,
 598                                      struct btrfs_pending_snapshot, list);
 599                 ret = create_pending_snapshot(trans, fs_info, pending);
 600                 BUG_ON(ret);
 601                 list_del(&pending->list);
 602                 kfree(pending->name);
 603                 kfree(pending);
 604         }
 605         return 0;
 606 }
 607
 608 int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
 609                              struct btrfs_root *root)
 610 {
 611         unsigned long joined = 0;
 612         unsigned long timeout = 1;
 613         struct btrfs_transaction *cur_trans;
 614         struct btrfs_transaction *prev_trans = NULL;
 615         struct list_head dirty_fs_roots;
 616         struct extent_map_tree *pinned_copy;
 617         DEFINE_WAIT(wait);
 618         int ret;
 619
 620         INIT_LIST_HEAD(&dirty_fs_roots);
 621
 622         mutex_lock(&root->fs_info->trans_mutex);
 623         if (trans->transaction->in_commit) {
 624                 cur_trans = trans->transaction;
 625                 trans->transaction->use_count++;
 626                 mutex_unlock(&root->fs_info->trans_mutex);
 627                 btrfs_end_transaction(trans, root);
 628
 629                 mutex_unlock(&root->fs_info->fs_mutex);
 630                 ret = wait_for_commit(root, cur_trans);
 631                 BUG_ON(ret);
 632
 633                 mutex_lock(&root->fs_info->trans_mutex);
 634                 put_transaction(cur_trans);
 635                 mutex_unlock(&root->fs_info->trans_mutex);
 636
 637                 mutex_lock(&root->fs_info->fs_mutex);
 638                 return 0;
 639         }
 640
 641         pinned_copy = kmalloc(sizeof(*pinned_copy), GFP_NOFS);
 642         if (!pinned_copy)
 643                 return -ENOMEM;
 644
 645         extent_map_tree_init(pinned_copy,
 646                              root->fs_info->btree_inode->i_mapping, GFP_NOFS);
 647
 648         trans->transaction->in_commit = 1;
 649         cur_trans = trans->transaction;
 650         if (cur_trans->list.prev != &root->fs_info->trans_list) {
 651                 prev_trans = list_entry(cur_trans->list.prev,
 652                                         struct btrfs_transaction, list);
 653                 if (!prev_trans->commit_done) {
 654                         prev_trans->use_count++;
 655                         mutex_unlock(&root->fs_info->fs_mutex);
 656                         mutex_unlock(&root->fs_info->trans_mutex);
 657
 658                         wait_for_commit(root, prev_trans);
 659
 660                         mutex_lock(&root->fs_info->fs_mutex);
 661                         mutex_lock(&root->fs_info->trans_mutex);
 662                         put_transaction(prev_trans);
 663                 }
 664         }
 665
 666         do {
 667                 joined = cur_trans->num_joined;
 668                 WARN_ON(cur_trans != trans->transaction);
 669                 prepare_to_wait(&cur_trans->writer_wait, &wait,
 670                                 TASK_UNINTERRUPTIBLE);
 671
 672                 if (cur_trans->num_writers > 1)
 673                         timeout = MAX_SCHEDULE_TIMEOUT;
 674                 else
 675                         timeout = 1;
 676
 677                 mutex_unlock(&root->fs_info->fs_mutex);
 678                 mutex_unlock(&root->fs_info->trans_mutex);
 679
 680                 schedule_timeout(timeout);
 681
 682                 mutex_lock(&root->fs_info->fs_mutex);
 683                 mutex_lock(&root->fs_info->trans_mutex);
 684                 finish_wait(&cur_trans->writer_wait, &wait);
 685                 ret = btrfs_write_ordered_inodes(trans, root);
 686
 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         write_extent_buffer(root->fs_info->sb_buffer,
 714                             &root->fs_info->super_copy, 0,
 715                             sizeof(root->fs_info->super_copy));
 716
 717         btrfs_copy_pinned(root, pinned_copy);
 718
 719         mutex_unlock(&root->fs_info->trans_mutex);
 720         mutex_unlock(&root->fs_info->fs_mutex);
 721         ret = btrfs_write_and_wait_transaction(trans, root);
 722         BUG_ON(ret);
 723         write_ctree_super(trans, root);
 724
 725         mutex_lock(&root->fs_info->fs_mutex);
 726         btrfs_finish_extent_commit(trans, root, pinned_copy);
 727         mutex_lock(&root->fs_info->trans_mutex);
 728
 729         kfree(pinned_copy);
 730
 731         cur_trans->commit_done = 1;
 732         root->fs_info->last_trans_committed = cur_trans->transid;
 733         wake_up(&cur_trans->commit_wait);
 734         put_transaction(cur_trans);
 735         put_transaction(cur_trans);
 736
 737         if (root->fs_info->closing)
 738                 list_splice_init(&root->fs_info->dead_roots, &dirty_fs_roots);
 739         else
 740                 list_splice_init(&dirty_fs_roots, &root->fs_info->dead_roots);
 741
 742         mutex_unlock(&root->fs_info->trans_mutex);
 743         kmem_cache_free(btrfs_trans_handle_cachep, trans);
 744
 745         if (root->fs_info->closing) {
 746                 mutex_unlock(&root->fs_info->fs_mutex);
 747                 drop_dirty_roots(root->fs_info->tree_root, &dirty_fs_roots);
 748                 mutex_lock(&root->fs_info->fs_mutex);
 749         }
 750         return ret;
 751 }
 752
 753 int btrfs_clean_old_snapshots(struct btrfs_root *root)
 754 {
 755         struct list_head dirty_roots;
 756         INIT_LIST_HEAD(&dirty_roots);
 757
 758         mutex_lock(&root->fs_info->trans_mutex);
 759         list_splice_init(&root->fs_info->dead_roots, &dirty_roots);
 760         mutex_unlock(&root->fs_info->trans_mutex);
 761
 762         if (!list_empty(&dirty_roots)) {
 763                 drop_dirty_roots(root, &dirty_roots);
 764         }
 765         return 0;
 766 }
 767 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,18)
 768 void btrfs_transaction_cleaner(void *p)
 769 #else
 770 void btrfs_transaction_cleaner(struct work_struct *work)
 771 #endif
 772 {
 773 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,18)
 774         struct btrfs_fs_info *fs_info = p;
 775 #else
 776         struct btrfs_fs_info *fs_info = container_of(work,
 777                                                      struct btrfs_fs_info,
 778                                                      trans_work.work);
 779
 780 #endif
 781         struct btrfs_root *root = fs_info->tree_root;
 782         struct btrfs_transaction *cur;
 783         struct btrfs_trans_handle *trans;
 784         unsigned long now;
 785         unsigned long delay = HZ * 30;
 786         int ret;
 787
 788         mutex_lock(&root->fs_info->fs_mutex);
 789         mutex_lock(&root->fs_info->trans_mutex);
 790         cur = root->fs_info->running_transaction;
 791         if (!cur) {
 792                 mutex_unlock(&root->fs_info->trans_mutex);
 793                 goto out;
 794         }
 795         now = get_seconds();
 796         if (now < cur->start_time || now - cur->start_time < 30) {
 797                 mutex_unlock(&root->fs_info->trans_mutex);
 798                 delay = HZ * 5;
 799                 goto out;
 800         }
 801         mutex_unlock(&root->fs_info->trans_mutex);
 802         btrfs_defrag_dirty_roots(root->fs_info);
 803         trans = btrfs_start_transaction(root, 1);
 804         ret = btrfs_commit_transaction(trans, root);
 805 out:
 806         mutex_unlock(&root->fs_info->fs_mutex);
 807         btrfs_clean_old_snapshots(root);
 808         btrfs_transaction_queue_work(root, delay);
 809 }
 810
 811 void btrfs_transaction_queue_work(struct btrfs_root *root, int delay)
 812 {
 813         queue_delayed_work(trans_wq, &root->fs_info->trans_work, delay);
 814 }
 815
 816 void btrfs_transaction_flush_work(struct btrfs_root *root)
 817 {
 818         cancel_rearming_delayed_workqueue(trans_wq, &root->fs_info->trans_work);
 819         flush_workqueue(trans_wq);
 820 }
 821
 822 void __init btrfs_init_transaction_sys(void)
 823 {
 824         trans_wq = create_workqueue("btrfs");
 825 }
 826
 827 void btrfs_exit_transaction_sys(void)
 828 {
 829         destroy_workqueue(trans_wq);
 830 }
 831