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                 root->fs_info->last_alloc = 0;
  61                 cur_trans->num_writers = 1;
  62                 cur_trans->num_joined = 0;
  63                 cur_trans->transid = root->fs_info->generation;
  64                 init_waitqueue_head(&cur_trans->writer_wait);
  65                 init_waitqueue_head(&cur_trans->commit_wait);
  66                 cur_trans->in_commit = 0;
  67                 cur_trans->use_count = 1;
  68                 cur_trans->commit_done = 0;
  69                 cur_trans->start_time = get_seconds();
  70                 INIT_LIST_HEAD(&cur_trans->pending_snapshots);
  71                 list_add_tail(&cur_trans->list, &root->fs_info->trans_list);
  72                 btrfs_ordered_inode_tree_init(&cur_trans->ordered_inode_tree);
  73                 extent_io_tree_init(&cur_trans->dirty_pages,
  74                                      root->fs_info->btree_inode->i_mapping,
  75                                      GFP_NOFS);
  76         } else {
  77                 cur_trans->num_writers++;
  78                 cur_trans->num_joined++;
  79         }
  80
  81         return 0;
  82 }
  83
  84 static int record_root_in_trans(struct btrfs_root *root)
  85 {
  86         u64 running_trans_id = root->fs_info->running_transaction->transid;
  87         if (root->ref_cows && root->last_trans < running_trans_id) {
  88                 WARN_ON(root == root->fs_info->extent_root);
  89                 if (root->root_item.refs != 0) {
  90                         radix_tree_tag_set(&root->fs_info->fs_roots_radix,
  91                                    (unsigned long)root->root_key.objectid,
  92                                    BTRFS_ROOT_TRANS_TAG);
  93                         radix_tree_tag_set(&root->fs_info->fs_roots_radix,
  94                                    (unsigned long)root->root_key.objectid,
  95                                    BTRFS_ROOT_DEFRAG_TAG);
  96                         root->commit_root = root->node;
  97                         extent_buffer_get(root->node);
  98                 } else {
  99                         WARN_ON(1);
 100                 }
 101                 root->last_trans = running_trans_id;
 102         }
 103         return 0;
 104 }
 105
 106 struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
 107                                                    int num_blocks)
 108 {
 109         struct btrfs_trans_handle *h =
 110                 kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS);
 111         int ret;
 112
 113         mutex_lock(&root->fs_info->trans_mutex);
 114         ret = join_transaction(root);
 115         BUG_ON(ret);
 116
 117         record_root_in_trans(root);
 118         h->transid = root->fs_info->running_transaction->transid;
 119         h->transaction = root->fs_info->running_transaction;
 120         h->blocks_reserved = num_blocks;
 121         h->blocks_used = 0;
 122         h->block_group = NULL;
 123         h->alloc_exclude_nr = 0;
 124         h->alloc_exclude_start = 0;
 125         root->fs_info->running_transaction->use_count++;
 126         mutex_unlock(&root->fs_info->trans_mutex);
 127         return h;
 128 }
 129
 130 int btrfs_end_transaction(struct btrfs_trans_handle *trans,
 131                           struct btrfs_root *root)
 132 {
 133         struct btrfs_transaction *cur_trans;
 134
 135         mutex_lock(&root->fs_info->trans_mutex);
 136         cur_trans = root->fs_info->running_transaction;
 137         WARN_ON(cur_trans != trans->transaction);
 138         WARN_ON(cur_trans->num_writers < 1);
 139         cur_trans->num_writers--;
 140         if (waitqueue_active(&cur_trans->writer_wait))
 141                 wake_up(&cur_trans->writer_wait);
 142         put_transaction(cur_trans);
 143         mutex_unlock(&root->fs_info->trans_mutex);
 144         memset(trans, 0, sizeof(*trans));
 145         kmem_cache_free(btrfs_trans_handle_cachep, trans);
 146         return 0;
 147 }
 148
 149
 150 int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans,
 151                                      struct btrfs_root *root)
 152 {
 153         int ret;
 154         int err;
 155         int werr = 0;
 156         struct extent_io_tree *dirty_pages;
 157         struct page *page;
 158         struct inode *btree_inode = root->fs_info->btree_inode;
 159         u64 start;
 160         u64 end;
 161         unsigned long index;
 162
 163         if (!trans || !trans->transaction) {
 164                 return filemap_write_and_wait(btree_inode->i_mapping);
 165         }
 166         dirty_pages = &trans->transaction->dirty_pages;
 167         while(1) {
 168                 ret = find_first_extent_bit(dirty_pages, 0, &start, &end,
 169                                             EXTENT_DIRTY);
 170                 if (ret)
 171                         break;
 172                 clear_extent_dirty(dirty_pages, start, end, GFP_NOFS);
 173                 while(start <= end) {
 174                         index = start >> PAGE_CACHE_SHIFT;
 175                         start = (u64)(index + 1) << PAGE_CACHE_SHIFT;
 176                         page = find_lock_page(btree_inode->i_mapping, index);
 177                         if (!page)
 178                                 continue;
 179                         if (PageWriteback(page)) {
 180                                 if (PageDirty(page))
 181                                         wait_on_page_writeback(page);
 182                                 else {
 183                                         unlock_page(page);
 184                                         page_cache_release(page);
 185                                         continue;
 186                                 }
 187                         }
 188                         err = write_one_page(page, 0);
 189                         if (err)
 190                                 werr = err;
 191                         page_cache_release(page);
 192                 }
 193         }
 194         err = filemap_fdatawait(btree_inode->i_mapping);
 195         if (err)
 196                 werr = err;
 197         return werr;
 198 }
 199
 200 int btrfs_commit_tree_roots(struct btrfs_trans_handle *trans,
 201                             struct btrfs_root *root)
 202 {
 203         int ret;
 204         u64 old_extent_block;
 205         struct btrfs_fs_info *fs_info = root->fs_info;
 206         struct btrfs_root *tree_root = fs_info->tree_root;
 207         struct btrfs_root *extent_root = fs_info->extent_root;
 208
 209         btrfs_write_dirty_block_groups(trans, extent_root);
 210         while(1) {
 211                 old_extent_block = btrfs_root_bytenr(&extent_root->root_item);
 212                 if (old_extent_block == extent_root->node->start)
 213                         break;
 214                 btrfs_set_root_bytenr(&extent_root->root_item,
 215                                       extent_root->node->start);
 216                 btrfs_set_root_level(&extent_root->root_item,
 217                                      btrfs_header_level(extent_root->node));
 218                 ret = btrfs_update_root(trans, tree_root,
 219                                         &extent_root->root_key,
 220                                         &extent_root->root_item);
 221                 BUG_ON(ret);
 222                 btrfs_write_dirty_block_groups(trans, extent_root);
 223         }
 224         return 0;
 225 }
 226
 227 static int wait_for_commit(struct btrfs_root *root,
 228                            struct btrfs_transaction *commit)
 229 {
 230         DEFINE_WAIT(wait);
 231         mutex_lock(&root->fs_info->trans_mutex);
 232         while(!commit->commit_done) {
 233                 prepare_to_wait(&commit->commit_wait, &wait,
 234                                 TASK_UNINTERRUPTIBLE);
 235                 if (commit->commit_done)
 236                         break;
 237                 mutex_unlock(&root->fs_info->trans_mutex);
 238                 schedule();
 239                 mutex_lock(&root->fs_info->trans_mutex);
 240         }
 241         mutex_unlock(&root->fs_info->trans_mutex);
 242         finish_wait(&commit->commit_wait, &wait);
 243         return 0;
 244 }
 245
 246 struct dirty_root {
 247         struct list_head list;
 248         struct btrfs_root *root;
 249         struct btrfs_root *latest_root;
 250 };
 251
 252 int btrfs_add_dead_root(struct btrfs_root *root,
 253                         struct btrfs_root *latest,
 254                         struct list_head *dead_list)
 255 {
 256         struct dirty_root *dirty;
 257
 258         dirty = kmalloc(sizeof(*dirty), GFP_NOFS);
 259         if (!dirty)
 260                 return -ENOMEM;
 261         dirty->root = root;
 262         dirty->latest_root = latest;
 263         list_add(&dirty->list, dead_list);
 264         return 0;
 265 }
 266
 267 static int add_dirty_roots(struct btrfs_trans_handle *trans,
 268                            struct radix_tree_root *radix,
 269                            struct list_head *list)
 270 {
 271         struct dirty_root *dirty;
 272         struct btrfs_root *gang[8];
 273         struct btrfs_root *root;
 274         int i;
 275         int ret;
 276         int err = 0;
 277         u32 refs;
 278
 279         while(1) {
 280                 ret = radix_tree_gang_lookup_tag(radix, (void **)gang, 0,
 281                                                  ARRAY_SIZE(gang),
 282                                                  BTRFS_ROOT_TRANS_TAG);
 283                 if (ret == 0)
 284                         break;
 285                 for (i = 0; i < ret; i++) {
 286                         root = gang[i];
 287                         radix_tree_tag_clear(radix,
 288                                      (unsigned long)root->root_key.objectid,
 289                                      BTRFS_ROOT_TRANS_TAG);
 290                         if (root->commit_root == root->node) {
 291                                 WARN_ON(root->node->start !=
 292                                         btrfs_root_bytenr(&root->root_item));
 293                                 free_extent_buffer(root->commit_root);
 294                                 root->commit_root = NULL;
 295
 296                                 /* make sure to update the root on disk
 297                                  * so we get any updates to the block used
 298                                  * counts
 299                                  */
 300                                 err = btrfs_update_root(trans,
 301                                                 root->fs_info->tree_root,
 302                                                 &root->root_key,
 303                                                 &root->root_item);
 304                                 continue;
 305                         }
 306                         dirty = kmalloc(sizeof(*dirty), GFP_NOFS);
 307                         BUG_ON(!dirty);
 308                         dirty->root = kmalloc(sizeof(*dirty->root), GFP_NOFS);
 309                         BUG_ON(!dirty->root);
 310
 311                         memset(&root->root_item.drop_progress, 0,
 312                                sizeof(struct btrfs_disk_key));
 313                         root->root_item.drop_level = 0;
 314
 315                         memcpy(dirty->root, root, sizeof(*root));
 316                         dirty->root->node = root->commit_root;
 317                         dirty->latest_root = root;
 318                         root->commit_root = NULL;
 319
 320                         root->root_key.offset = root->fs_info->generation;
 321                         btrfs_set_root_bytenr(&root->root_item,
 322                                               root->node->start);
 323                         btrfs_set_root_level(&root->root_item,
 324                                              btrfs_header_level(root->node));
 325                         err = btrfs_insert_root(trans, root->fs_info->tree_root,
 326                                                 &root->root_key,
 327                                                 &root->root_item);
 328                         if (err)
 329                                 break;
 330
 331                         refs = btrfs_root_refs(&dirty->root->root_item);
 332                         btrfs_set_root_refs(&dirty->root->root_item, refs - 1);
 333                         err = btrfs_update_root(trans, root->fs_info->tree_root,
 334                                                 &dirty->root->root_key,
 335                                                 &dirty->root->root_item);
 336
 337                         BUG_ON(err);
 338                         if (refs == 1) {
 339                                 list_add(&dirty->list, list);
 340                         } else {
 341                                 WARN_ON(1);
 342                                 kfree(dirty->root);
 343                                 kfree(dirty);
 344                         }
 345                 }
 346         }
 347         return err;
 348 }
 349
 350 int btrfs_defrag_root(struct btrfs_root *root, int cacheonly)
 351 {
 352         struct btrfs_fs_info *info = root->fs_info;
 353         int ret;
 354         struct btrfs_trans_handle *trans;
 355         unsigned long nr;
 356
 357         if (root->defrag_running)
 358                 return 0;
 359         trans = btrfs_start_transaction(root, 1);
 360         while (1) {
 361                 root->defrag_running = 1;
 362                 ret = btrfs_defrag_leaves(trans, root, cacheonly);
 363                 nr = trans->blocks_used;
 364                 btrfs_end_transaction(trans, root);
 365                 mutex_unlock(&info->fs_mutex);
 366                 btrfs_btree_balance_dirty(info->tree_root, nr);
 367                 cond_resched();
 368
 369                 mutex_lock(&info->fs_mutex);
 370                 trans = btrfs_start_transaction(root, 1);
 371                 if (ret != -EAGAIN)
 372                         break;
 373         }
 374         root->defrag_running = 0;
 375         radix_tree_tag_clear(&info->fs_roots_radix,
 376                      (unsigned long)root->root_key.objectid,
 377                      BTRFS_ROOT_DEFRAG_TAG);
 378         btrfs_end_transaction(trans, root);
 379         return 0;
 380 }
 381
 382 int btrfs_defrag_dirty_roots(struct btrfs_fs_info *info)
 383 {
 384         struct btrfs_root *gang[1];
 385         struct btrfs_root *root;
 386         int i;
 387         int ret;
 388         int err = 0;
 389         u64 last = 0;
 390
 391         while(1) {
 392                 ret = radix_tree_gang_lookup_tag(&info->fs_roots_radix,
 393                                                  (void **)gang, last,
 394                                                  ARRAY_SIZE(gang),
 395                                                  BTRFS_ROOT_DEFRAG_TAG);
 396                 if (ret == 0)
 397                         break;
 398                 for (i = 0; i < ret; i++) {
 399                         root = gang[i];
 400                         last = root->root_key.objectid + 1;
 401                         btrfs_defrag_root(root, 1);
 402                 }
 403         }
 404         btrfs_defrag_root(info->extent_root, 1);
 405         return err;
 406 }
 407
 408 static int drop_dirty_roots(struct btrfs_root *tree_root,
 409                             struct list_head *list)
 410 {
 411         struct dirty_root *dirty;
 412         struct btrfs_trans_handle *trans;
 413         unsigned long nr;
 414         u64 num_bytes;
 415         u64 bytes_used;
 416         int ret = 0;
 417         int err;
 418
 419         while(!list_empty(list)) {
 420                 struct btrfs_root *root;
 421
 422                 mutex_lock(&tree_root->fs_info->fs_mutex);
 423                 dirty = list_entry(list->next, struct dirty_root, list);
 424                 list_del_init(&dirty->list);
 425
 426                 num_bytes = btrfs_root_used(&dirty->root->root_item);
 427                 root = dirty->latest_root;
 428                 root->fs_info->throttles++;
 429
 430                 while(1) {
 431                         trans = btrfs_start_transaction(tree_root, 1);
 432                         ret = btrfs_drop_snapshot(trans, dirty->root);
 433                         if (ret != -EAGAIN) {
 434                                 break;
 435                         }
 436
 437                         err = btrfs_update_root(trans,
 438                                         tree_root,
 439                                         &dirty->root->root_key,
 440                                         &dirty->root->root_item);
 441                         if (err)
 442                                 ret = err;
 443                         nr = trans->blocks_used;
 444                         ret = btrfs_end_transaction(trans, tree_root);
 445                         BUG_ON(ret);
 446                         mutex_unlock(&tree_root->fs_info->fs_mutex);
 447                         btrfs_btree_balance_dirty(tree_root, nr);
 448                         cond_resched();
 449                         mutex_lock(&tree_root->fs_info->fs_mutex);
 450                 }
 451                 BUG_ON(ret);
 452                 root->fs_info->throttles--;
 453
 454                 num_bytes -= btrfs_root_used(&dirty->root->root_item);
 455                 bytes_used = btrfs_root_used(&root->root_item);
 456                 if (num_bytes) {
 457                         record_root_in_trans(root);
 458                         btrfs_set_root_used(&root->root_item,
 459                                             bytes_used - num_bytes);
 460                 }
 461                 ret = btrfs_del_root(trans, tree_root, &dirty->root->root_key);
 462                 if (ret) {
 463                         BUG();
 464                         break;
 465                 }
 466                 nr = trans->blocks_used;
 467                 ret = btrfs_end_transaction(trans, tree_root);
 468                 BUG_ON(ret);
 469
 470                 free_extent_buffer(dirty->root->node);
 471                 kfree(dirty->root);
 472                 kfree(dirty);
 473                 mutex_unlock(&tree_root->fs_info->fs_mutex);
 474
 475                 btrfs_btree_balance_dirty(tree_root, nr);
 476                 cond_resched();
 477         }
 478         return ret;
 479 }
 480
 481 int btrfs_write_ordered_inodes(struct btrfs_trans_handle *trans,
 482                                 struct btrfs_root *root)
 483 {
 484         struct btrfs_transaction *cur_trans = trans->transaction;
 485         struct inode *inode;
 486         u64 root_objectid = 0;
 487         u64 objectid = 0;
 488         int ret;
 489
 490         root->fs_info->throttles++;
 491         while(1) {
 492                 ret = btrfs_find_first_ordered_inode(
 493                                 &cur_trans->ordered_inode_tree,
 494                                 &root_objectid, &objectid, &inode);
 495                 if (!ret)
 496                         break;
 497
 498                 mutex_unlock(&root->fs_info->trans_mutex);
 499                 mutex_unlock(&root->fs_info->fs_mutex);
 500
 501                 if (S_ISREG(inode->i_mode))
 502                         filemap_fdatawrite(inode->i_mapping);
 503                 iput(inode);
 504
 505                 mutex_lock(&root->fs_info->fs_mutex);
 506                 mutex_lock(&root->fs_info->trans_mutex);
 507         }
 508         while(1) {
 509                 root_objectid = 0;
 510                 objectid = 0;
 511                 ret = btrfs_find_del_first_ordered_inode(
 512                                 &cur_trans->ordered_inode_tree,
 513                                 &root_objectid, &objectid, &inode);
 514                 if (!ret)
 515                         break;
 516                 mutex_unlock(&root->fs_info->trans_mutex);
 517                 mutex_unlock(&root->fs_info->fs_mutex);
 518
 519                 if (S_ISREG(inode->i_mode))
 520                         filemap_write_and_wait(inode->i_mapping);
 521                 atomic_dec(&inode->i_count);
 522                 iput(inode);
 523
 524                 mutex_lock(&root->fs_info->fs_mutex);
 525                 mutex_lock(&root->fs_info->trans_mutex);
 526         }
 527         root->fs_info->throttles--;
 528         return 0;
 529 }
 530
 531 static int create_pending_snapshot(struct btrfs_trans_handle *trans,
 532                                    struct btrfs_fs_info *fs_info,
 533                                    struct btrfs_pending_snapshot *pending)
 534 {
 535         struct btrfs_key key;
 536         struct btrfs_root_item new_root_item;
 537         struct btrfs_root *tree_root = fs_info->tree_root;
 538         struct btrfs_root *root = pending->root;
 539         struct extent_buffer *tmp;
 540         int ret;
 541         u64 objectid;
 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         extent_buffer_get(root->node);
 554         btrfs_cow_block(trans, root, root->node, NULL, 0, &tmp);
 555         free_extent_buffer(tmp);
 556
 557         btrfs_copy_root(trans, root, root->node, &tmp, objectid);
 558
 559         btrfs_set_root_bytenr(&new_root_item, tmp->start);
 560         btrfs_set_root_level(&new_root_item, btrfs_header_level(tmp));
 561         ret = btrfs_insert_root(trans, root->fs_info->tree_root, &key,
 562                                 &new_root_item);
 563         free_extent_buffer(tmp);
 564         if (ret)
 565                 goto fail;
 566
 567         /*
 568          * insert the directory item
 569          */
 570         key.offset = (u64)-1;
 571         ret = btrfs_insert_dir_item(trans, root->fs_info->tree_root,
 572                                     pending->name, strlen(pending->name),
 573                                     root->fs_info->sb->s_root->d_inode->i_ino,
 574                                     &key, BTRFS_FT_DIR);
 575
 576         if (ret)
 577                 goto fail;
 578
 579         ret = btrfs_insert_inode_ref(trans, root->fs_info->tree_root,
 580                              pending->name, strlen(pending->name), objectid,
 581                              root->fs_info->sb->s_root->d_inode->i_ino);
 582 fail:
 583         return ret;
 584 }
 585
 586 static int create_pending_snapshots(struct btrfs_trans_handle *trans,
 587                                    struct btrfs_fs_info *fs_info)
 588 {
 589         struct btrfs_pending_snapshot *pending;
 590         struct list_head *head = &trans->transaction->pending_snapshots;
 591         int ret;
 592
 593         while(!list_empty(head)) {
 594                 pending = list_entry(head->next,
 595                                      struct btrfs_pending_snapshot, list);
 596                 ret = create_pending_snapshot(trans, fs_info, pending);
 597                 BUG_ON(ret);
 598                 list_del(&pending->list);
 599                 kfree(pending->name);
 600                 kfree(pending);
 601         }
 602         return 0;
 603 }
 604
 605 int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
 606                              struct btrfs_root *root)
 607 {
 608         unsigned long joined = 0;
 609         unsigned long timeout = 1;
 610         struct btrfs_transaction *cur_trans;
 611         struct btrfs_transaction *prev_trans = NULL;
 612         struct list_head dirty_fs_roots;
 613         struct extent_io_tree *pinned_copy;
 614         DEFINE_WAIT(wait);
 615         int ret;
 616
 617         INIT_LIST_HEAD(&dirty_fs_roots);
 618
 619         mutex_lock(&root->fs_info->trans_mutex);
 620         if (trans->transaction->in_commit) {
 621                 cur_trans = trans->transaction;
 622                 trans->transaction->use_count++;
 623                 mutex_unlock(&root->fs_info->trans_mutex);
 624                 btrfs_end_transaction(trans, root);
 625
 626                 mutex_unlock(&root->fs_info->fs_mutex);
 627                 ret = wait_for_commit(root, cur_trans);
 628                 BUG_ON(ret);
 629
 630                 mutex_lock(&root->fs_info->trans_mutex);
 631                 put_transaction(cur_trans);
 632                 mutex_unlock(&root->fs_info->trans_mutex);
 633
 634                 mutex_lock(&root->fs_info->fs_mutex);
 635                 return 0;
 636         }
 637
 638         pinned_copy = kmalloc(sizeof(*pinned_copy), GFP_NOFS);
 639         if (!pinned_copy)
 640                 return -ENOMEM;
 641
 642         extent_io_tree_init(pinned_copy,
 643                              root->fs_info->btree_inode->i_mapping, GFP_NOFS);
 644
 645         trans->transaction->in_commit = 1;
 646         cur_trans = trans->transaction;
 647         if (cur_trans->list.prev != &root->fs_info->trans_list) {
 648                 prev_trans = list_entry(cur_trans->list.prev,
 649                                         struct btrfs_transaction, list);
 650                 if (!prev_trans->commit_done) {
 651                         prev_trans->use_count++;
 652                         mutex_unlock(&root->fs_info->fs_mutex);
 653                         mutex_unlock(&root->fs_info->trans_mutex);
 654
 655                         wait_for_commit(root, prev_trans);
 656
 657                         mutex_lock(&root->fs_info->fs_mutex);
 658                         mutex_lock(&root->fs_info->trans_mutex);
 659                         put_transaction(prev_trans);
 660                 }
 661         }
 662
 663         do {
 664                 joined = cur_trans->num_joined;
 665                 WARN_ON(cur_trans != trans->transaction);
 666                 prepare_to_wait(&cur_trans->writer_wait, &wait,
 667                                 TASK_UNINTERRUPTIBLE);
 668
 669                 if (cur_trans->num_writers > 1)
 670                         timeout = MAX_SCHEDULE_TIMEOUT;
 671                 else
 672                         timeout = 1;
 673
 674                 mutex_unlock(&root->fs_info->fs_mutex);
 675                 mutex_unlock(&root->fs_info->trans_mutex);
 676
 677                 schedule_timeout(timeout);
 678
 679                 mutex_lock(&root->fs_info->fs_mutex);
 680                 mutex_lock(&root->fs_info->trans_mutex);
 681                 finish_wait(&cur_trans->writer_wait, &wait);
 682                 ret = btrfs_write_ordered_inodes(trans, root);
 683
 684         } while (cur_trans->num_writers > 1 ||
 685                  (cur_trans->num_joined != joined));
 686
 687         ret = create_pending_snapshots(trans, root->fs_info);
 688         BUG_ON(ret);
 689
 690         WARN_ON(cur_trans != trans->transaction);
 691
 692         ret = add_dirty_roots(trans, &root->fs_info->fs_roots_radix,
 693                               &dirty_fs_roots);
 694         BUG_ON(ret);
 695
 696         ret = btrfs_commit_tree_roots(trans, root);
 697         BUG_ON(ret);
 698
 699         cur_trans = root->fs_info->running_transaction;
 700         spin_lock(&root->fs_info->new_trans_lock);
 701         root->fs_info->running_transaction = NULL;
 702         spin_unlock(&root->fs_info->new_trans_lock);
 703         btrfs_set_super_generation(&root->fs_info->super_copy,
 704                                    cur_trans->transid);
 705         btrfs_set_super_root(&root->fs_info->super_copy,
 706                              root->fs_info->tree_root->node->start);
 707         btrfs_set_super_root_level(&root->fs_info->super_copy,
 708                            btrfs_header_level(root->fs_info->tree_root->node));
 709
 710         write_extent_buffer(root->fs_info->sb_buffer,
 711                             &root->fs_info->super_copy, 0,
 712                             sizeof(root->fs_info->super_copy));
 713
 714         btrfs_copy_pinned(root, pinned_copy);
 715
 716         mutex_unlock(&root->fs_info->trans_mutex);
 717         mutex_unlock(&root->fs_info->fs_mutex);
 718         ret = btrfs_write_and_wait_transaction(trans, root);
 719         BUG_ON(ret);
 720         write_ctree_super(trans, root);
 721
 722         mutex_lock(&root->fs_info->fs_mutex);
 723         btrfs_finish_extent_commit(trans, root, pinned_copy);
 724         mutex_lock(&root->fs_info->trans_mutex);
 725
 726         kfree(pinned_copy);
 727
 728         cur_trans->commit_done = 1;
 729         root->fs_info->last_trans_committed = cur_trans->transid;
 730         wake_up(&cur_trans->commit_wait);
 731         put_transaction(cur_trans);
 732         put_transaction(cur_trans);
 733
 734         if (root->fs_info->closing)
 735                 list_splice_init(&root->fs_info->dead_roots, &dirty_fs_roots);
 736         else
 737                 list_splice_init(&dirty_fs_roots, &root->fs_info->dead_roots);
 738
 739         mutex_unlock(&root->fs_info->trans_mutex);
 740         kmem_cache_free(btrfs_trans_handle_cachep, trans);
 741
 742         if (root->fs_info->closing) {
 743                 mutex_unlock(&root->fs_info->fs_mutex);
 744                 drop_dirty_roots(root->fs_info->tree_root, &dirty_fs_roots);
 745                 mutex_lock(&root->fs_info->fs_mutex);
 746         }
 747         return ret;
 748 }
 749
 750 int btrfs_clean_old_snapshots(struct btrfs_root *root)
 751 {
 752         struct list_head dirty_roots;
 753         INIT_LIST_HEAD(&dirty_roots);
 754
 755         mutex_lock(&root->fs_info->trans_mutex);
 756         list_splice_init(&root->fs_info->dead_roots, &dirty_roots);
 757         mutex_unlock(&root->fs_info->trans_mutex);
 758
 759         if (!list_empty(&dirty_roots)) {
 760                 drop_dirty_roots(root, &dirty_roots);
 761         }
 762         return 0;
 763 }
 764 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,18)
 765 void btrfs_transaction_cleaner(void *p)
 766 #else
 767 void btrfs_transaction_cleaner(struct work_struct *work)
 768 #endif
 769 {
 770 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,18)
 771         struct btrfs_fs_info *fs_info = p;
 772 #else
 773         struct btrfs_fs_info *fs_info = container_of(work,
 774                                                      struct btrfs_fs_info,
 775                                                      trans_work.work);
 776
 777 #endif
 778         struct btrfs_root *root = fs_info->tree_root;
 779         struct btrfs_transaction *cur;
 780         struct btrfs_trans_handle *trans;
 781         unsigned long now;
 782         unsigned long delay = HZ * 30;
 783         int ret;
 784
 785         mutex_lock(&root->fs_info->fs_mutex);
 786         mutex_lock(&root->fs_info->trans_mutex);
 787         cur = root->fs_info->running_transaction;
 788         if (!cur) {
 789                 mutex_unlock(&root->fs_info->trans_mutex);
 790                 goto out;
 791         }
 792         now = get_seconds();
 793         if (now < cur->start_time || now - cur->start_time < 30) {
 794                 mutex_unlock(&root->fs_info->trans_mutex);
 795                 delay = HZ * 5;
 796                 goto out;
 797         }
 798         mutex_unlock(&root->fs_info->trans_mutex);
 799         btrfs_defrag_dirty_roots(root->fs_info);
 800         trans = btrfs_start_transaction(root, 1);
 801         ret = btrfs_commit_transaction(trans, root);
 802 out:
 803         mutex_unlock(&root->fs_info->fs_mutex);
 804         btrfs_clean_old_snapshots(root);
 805         btrfs_transaction_queue_work(root, delay);
 806 }
 807
 808 void btrfs_transaction_queue_work(struct btrfs_root *root, int delay)
 809 {
 810         queue_delayed_work(trans_wq, &root->fs_info->trans_work, delay);
 811 }
 812
 813 void btrfs_transaction_flush_work(struct btrfs_root *root)
 814 {
 815         cancel_rearming_delayed_workqueue(trans_wq, &root->fs_info->trans_work);
 816         flush_workqueue(trans_wq);
 817 }
 818
 819 void __init btrfs_init_transaction_sys(void)
 820 {
 821         trans_wq = create_workqueue("btrfs");
 822 }
 823
 824 void btrfs_exit_transaction_sys(void)
 825 {
 826         destroy_workqueue(trans_wq);
 827 }
 828