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   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                         spin_lock_init(&dirty->root->node_lock);
 386                         mutex_init(&dirty->root->objectid_mutex);
 387
 388                         root->commit_root = NULL;
 389
 390                         root->root_key.offset = root->fs_info->generation;
 391                         btrfs_set_root_bytenr(&root->root_item,
 392                                               root->node->start);
 393                         btrfs_set_root_level(&root->root_item,
 394                                              btrfs_header_level(root->node));
 395                         err = btrfs_insert_root(trans, root->fs_info->tree_root,
 396                                                 &root->root_key,
 397                                                 &root->root_item);
 398                         if (err)
 399                                 break;
 400
 401                         refs = btrfs_root_refs(&dirty->root->root_item);
 402                         btrfs_set_root_refs(&dirty->root->root_item, refs - 1);
 403                         err = btrfs_update_root(trans, root->fs_info->tree_root,
 404                                                 &dirty->root->root_key,
 405                                                 &dirty->root->root_item);
 406
 407                         BUG_ON(err);
 408                         if (refs == 1) {
 409                                 list_add(&dirty->list, list);
 410                         } else {
 411                                 WARN_ON(1);
 412                                 kfree(dirty->root);
 413                                 kfree(dirty);
 414                         }
 415                 }
 416         }
 417         return err;
 418 }
 419
 420 int btrfs_defrag_root(struct btrfs_root *root, int cacheonly)
 421 {
 422         struct btrfs_fs_info *info = root->fs_info;
 423         int ret;
 424         struct btrfs_trans_handle *trans;
 425         unsigned long nr;
 426
 427         smp_mb();
 428         if (root->defrag_running)
 429                 return 0;
 430         trans = btrfs_start_transaction(root, 1);
 431         while (1) {
 432                 root->defrag_running = 1;
 433                 ret = btrfs_defrag_leaves(trans, root, cacheonly);
 434                 nr = trans->blocks_used;
 435                 btrfs_end_transaction(trans, root);
 436                 btrfs_btree_balance_dirty(info->tree_root, nr);
 437                 cond_resched();
 438
 439                 trans = btrfs_start_transaction(root, 1);
 440                 if (root->fs_info->closing || ret != -EAGAIN)
 441                         break;
 442         }
 443         root->defrag_running = 0;
 444         smp_mb();
 445         btrfs_end_transaction(trans, root);
 446         return 0;
 447 }
 448
 449 static noinline int drop_dirty_roots(struct btrfs_root *tree_root,
 450                                      struct list_head *list)
 451 {
 452         struct dirty_root *dirty;
 453         struct btrfs_trans_handle *trans;
 454         unsigned long nr;
 455         u64 num_bytes;
 456         u64 bytes_used;
 457         int ret = 0;
 458         int err;
 459
 460         while(!list_empty(list)) {
 461                 struct btrfs_root *root;
 462
 463                 dirty = list_entry(list->next, struct dirty_root, list);
 464                 list_del_init(&dirty->list);
 465
 466                 num_bytes = btrfs_root_used(&dirty->root->root_item);
 467                 root = dirty->latest_root;
 468                 atomic_inc(&root->fs_info->throttles);
 469
 470                 mutex_lock(&root->fs_info->drop_mutex);
 471                 while(1) {
 472                         trans = btrfs_start_transaction(tree_root, 1);
 473                         ret = btrfs_drop_snapshot(trans, dirty->root);
 474                         if (ret != -EAGAIN) {
 475                                 break;
 476                         }
 477
 478                         err = btrfs_update_root(trans,
 479                                         tree_root,
 480                                         &dirty->root->root_key,
 481                                         &dirty->root->root_item);
 482                         if (err)
 483                                 ret = err;
 484                         nr = trans->blocks_used;
 485                         ret = btrfs_end_transaction_throttle(trans, tree_root);
 486                         BUG_ON(ret);
 487
 488                         mutex_unlock(&root->fs_info->drop_mutex);
 489                         btrfs_btree_balance_dirty(tree_root, nr);
 490                         cond_resched();
 491                         mutex_lock(&root->fs_info->drop_mutex);
 492                 }
 493                 BUG_ON(ret);
 494                 atomic_dec(&root->fs_info->throttles);
 495
 496                 mutex_lock(&root->fs_info->alloc_mutex);
 497                 num_bytes -= btrfs_root_used(&dirty->root->root_item);
 498                 bytes_used = btrfs_root_used(&root->root_item);
 499                 if (num_bytes) {
 500                         record_root_in_trans(root);
 501                         btrfs_set_root_used(&root->root_item,
 502                                             bytes_used - num_bytes);
 503                 }
 504                 mutex_unlock(&root->fs_info->alloc_mutex);
 505
 506                 ret = btrfs_del_root(trans, tree_root, &dirty->root->root_key);
 507                 if (ret) {
 508                         BUG();
 509                         break;
 510                 }
 511                 mutex_unlock(&root->fs_info->drop_mutex);
 512
 513                 nr = trans->blocks_used;
 514                 ret = btrfs_end_transaction(trans, tree_root);
 515                 BUG_ON(ret);
 516
 517                 free_extent_buffer(dirty->root->node);
 518                 kfree(dirty->root);
 519                 kfree(dirty);
 520
 521                 btrfs_btree_balance_dirty(tree_root, nr);
 522                 cond_resched();
 523         }
 524         return ret;
 525 }
 526
 527 static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
 528                                    struct btrfs_fs_info *fs_info,
 529                                    struct btrfs_pending_snapshot *pending)
 530 {
 531         struct btrfs_key key;
 532         struct btrfs_root_item *new_root_item;
 533         struct btrfs_root *tree_root = fs_info->tree_root;
 534         struct btrfs_root *root = pending->root;
 535         struct extent_buffer *tmp;
 536         struct extent_buffer *old;
 537         int ret;
 538         int namelen;
 539         u64 objectid;
 540
 541         new_root_item = kmalloc(sizeof(*new_root_item), GFP_NOFS);
 542         if (!new_root_item) {
 543                 ret = -ENOMEM;
 544                 goto fail;
 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         old = btrfs_lock_root_node(root);
 557         btrfs_cow_block(trans, root, old, NULL, 0, &old);
 558
 559         btrfs_copy_root(trans, root, old, &tmp, objectid);
 560         btrfs_tree_unlock(old);
 561         free_extent_buffer(old);
 562
 563         btrfs_set_root_bytenr(new_root_item, tmp->start);
 564         btrfs_set_root_level(new_root_item, btrfs_header_level(tmp));
 565         ret = btrfs_insert_root(trans, root->fs_info->tree_root, &key,
 566                                 new_root_item);
 567         btrfs_tree_unlock(tmp);
 568         free_extent_buffer(tmp);
 569         if (ret)
 570                 goto fail;
 571
 572         /*
 573          * insert the directory item
 574          */
 575         key.offset = (u64)-1;
 576         namelen = strlen(pending->name);
 577         ret = btrfs_insert_dir_item(trans, root->fs_info->tree_root,
 578                                     pending->name, namelen,
 579                                     root->fs_info->sb->s_root->d_inode->i_ino,
 580                                     &key, BTRFS_FT_DIR);
 581
 582         if (ret)
 583                 goto fail;
 584
 585         ret = btrfs_insert_inode_ref(trans, root->fs_info->tree_root,
 586                              pending->name, strlen(pending->name), objectid,
 587                              root->fs_info->sb->s_root->d_inode->i_ino);
 588
 589         /* Invalidate existing dcache entry for new snapshot. */
 590         btrfs_invalidate_dcache_root(root, pending->name, namelen);
 591
 592 fail:
 593         kfree(new_root_item);
 594         return ret;
 595 }
 596
 597 static noinline int create_pending_snapshots(struct btrfs_trans_handle *trans,
 598                                              struct btrfs_fs_info *fs_info)
 599 {
 600         struct btrfs_pending_snapshot *pending;
 601         struct list_head *head = &trans->transaction->pending_snapshots;
 602         int ret;
 603
 604         while(!list_empty(head)) {
 605                 pending = list_entry(head->next,
 606                                      struct btrfs_pending_snapshot, list);
 607                 ret = create_pending_snapshot(trans, fs_info, pending);
 608                 BUG_ON(ret);
 609                 list_del(&pending->list);
 610                 kfree(pending->name);
 611                 kfree(pending);
 612         }
 613         return 0;
 614 }
 615
 616 int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
 617                              struct btrfs_root *root)
 618 {
 619         unsigned long joined = 0;
 620         unsigned long timeout = 1;
 621         struct btrfs_transaction *cur_trans;
 622         struct btrfs_transaction *prev_trans = NULL;
 623         struct btrfs_root *chunk_root = root->fs_info->chunk_root;
 624         struct list_head dirty_fs_roots;
 625         struct extent_io_tree *pinned_copy;
 626         DEFINE_WAIT(wait);
 627         int ret;
 628
 629         INIT_LIST_HEAD(&dirty_fs_roots);
 630
 631         mutex_lock(&root->fs_info->trans_mutex);
 632         if (trans->transaction->in_commit) {
 633                 cur_trans = trans->transaction;
 634                 trans->transaction->use_count++;
 635                 mutex_unlock(&root->fs_info->trans_mutex);
 636                 btrfs_end_transaction(trans, root);
 637
 638                 ret = wait_for_commit(root, cur_trans);
 639                 BUG_ON(ret);
 640
 641                 mutex_lock(&root->fs_info->trans_mutex);
 642                 put_transaction(cur_trans);
 643                 mutex_unlock(&root->fs_info->trans_mutex);
 644
 645                 return 0;
 646         }
 647
 648         pinned_copy = kmalloc(sizeof(*pinned_copy), GFP_NOFS);
 649         if (!pinned_copy)
 650                 return -ENOMEM;
 651
 652         extent_io_tree_init(pinned_copy,
 653                              root->fs_info->btree_inode->i_mapping, GFP_NOFS);
 654
 655         trans->transaction->in_commit = 1;
 656         trans->transaction->blocked = 1;
 657         cur_trans = trans->transaction;
 658         if (cur_trans->list.prev != &root->fs_info->trans_list) {
 659                 prev_trans = list_entry(cur_trans->list.prev,
 660                                         struct btrfs_transaction, list);
 661                 if (!prev_trans->commit_done) {
 662                         prev_trans->use_count++;
 663                         mutex_unlock(&root->fs_info->trans_mutex);
 664
 665                         wait_for_commit(root, prev_trans);
 666
 667                         mutex_lock(&root->fs_info->trans_mutex);
 668                         put_transaction(prev_trans);
 669                 }
 670         }
 671
 672         do {
 673                 joined = cur_trans->num_joined;
 674                 WARN_ON(cur_trans != trans->transaction);
 675                 prepare_to_wait(&cur_trans->writer_wait, &wait,
 676                                 TASK_UNINTERRUPTIBLE);
 677
 678                 if (cur_trans->num_writers > 1)
 679                         timeout = MAX_SCHEDULE_TIMEOUT;
 680                 else
 681                         timeout = 1;
 682
 683                 mutex_unlock(&root->fs_info->trans_mutex);
 684
 685                 schedule_timeout(timeout);
 686
 687                 mutex_lock(&root->fs_info->trans_mutex);
 688                 finish_wait(&cur_trans->writer_wait, &wait);
 689         } while (cur_trans->num_writers > 1 ||
 690                  (cur_trans->num_joined != joined));
 691
 692         ret = create_pending_snapshots(trans, root->fs_info);
 693         BUG_ON(ret);
 694
 695         WARN_ON(cur_trans != trans->transaction);
 696
 697         ret = add_dirty_roots(trans, &root->fs_info->fs_roots_radix,
 698                               &dirty_fs_roots);
 699         BUG_ON(ret);
 700
 701         ret = btrfs_commit_tree_roots(trans, root);
 702         BUG_ON(ret);
 703
 704         cur_trans = root->fs_info->running_transaction;
 705         spin_lock(&root->fs_info->new_trans_lock);
 706         root->fs_info->running_transaction = NULL;
 707         spin_unlock(&root->fs_info->new_trans_lock);
 708         btrfs_set_super_generation(&root->fs_info->super_copy,
 709                                    cur_trans->transid);
 710         btrfs_set_super_root(&root->fs_info->super_copy,
 711                              root->fs_info->tree_root->node->start);
 712         btrfs_set_super_root_level(&root->fs_info->super_copy,
 713                            btrfs_header_level(root->fs_info->tree_root->node));
 714
 715         btrfs_set_super_chunk_root(&root->fs_info->super_copy,
 716                                    chunk_root->node->start);
 717         btrfs_set_super_chunk_root_level(&root->fs_info->super_copy,
 718                                          btrfs_header_level(chunk_root->node));
 719         memcpy(&root->fs_info->super_for_commit, &root->fs_info->super_copy,
 720                sizeof(root->fs_info->super_copy));
 721
 722         btrfs_copy_pinned(root, pinned_copy);
 723
 724         trans->transaction->blocked = 0;
 725         wake_up(&root->fs_info->transaction_throttle);
 726         wake_up(&root->fs_info->transaction_wait);
 727
 728         mutex_unlock(&root->fs_info->trans_mutex);
 729         ret = btrfs_write_and_wait_transaction(trans, root);
 730         BUG_ON(ret);
 731         write_ctree_super(trans, root);
 732
 733         btrfs_finish_extent_commit(trans, root, pinned_copy);
 734         mutex_lock(&root->fs_info->trans_mutex);
 735
 736         kfree(pinned_copy);
 737
 738         cur_trans->commit_done = 1;
 739         root->fs_info->last_trans_committed = cur_trans->transid;
 740         wake_up(&cur_trans->commit_wait);
 741         put_transaction(cur_trans);
 742         put_transaction(cur_trans);
 743
 744         if (root->fs_info->closing)
 745                 list_splice_init(&root->fs_info->dead_roots, &dirty_fs_roots);
 746         else
 747                 list_splice_init(&dirty_fs_roots, &root->fs_info->dead_roots);
 748
 749         mutex_unlock(&root->fs_info->trans_mutex);
 750         kmem_cache_free(btrfs_trans_handle_cachep, trans);
 751
 752         if (root->fs_info->closing) {
 753                 drop_dirty_roots(root->fs_info->tree_root, &dirty_fs_roots);
 754         }
 755         return ret;
 756 }
 757
 758 int btrfs_clean_old_snapshots(struct btrfs_root *root)
 759 {
 760         struct list_head dirty_roots;
 761         INIT_LIST_HEAD(&dirty_roots);
 762 again:
 763         mutex_lock(&root->fs_info->trans_mutex);
 764         list_splice_init(&root->fs_info->dead_roots, &dirty_roots);
 765         mutex_unlock(&root->fs_info->trans_mutex);
 766
 767         if (!list_empty(&dirty_roots)) {
 768                 drop_dirty_roots(root, &dirty_roots);
 769                 goto again;
 770         }
 771         return 0;
 772 }
 773