diff options
Diffstat (limited to 'fs/btrfs/volumes.c')
| -rw-r--r-- | fs/btrfs/volumes.c | 48 |
1 files changed, 43 insertions, 5 deletions
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index d4cd4059bded..9b95503ddd00 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -2766,6 +2766,20 @@ static int btrfs_relocate_chunk(struct btrfs_root *root, root = root->fs_info->chunk_root; extent_root = root->fs_info->extent_root; + /* + * Prevent races with automatic removal of unused block groups. + * After we relocate and before we remove the chunk with offset + * chunk_offset, automatic removal of the block group can kick in, + * resulting in a failure when calling btrfs_remove_chunk() below. + * + * Make sure to acquire this mutex before doing a tree search (dev + * or chunk trees) to find chunks. Otherwise the cleaner kthread might + * call btrfs_remove_chunk() (through btrfs_delete_unused_bgs()) after + * we release the path used to search the chunk/dev tree and before + * the current task acquires this mutex and calls us. + */ + ASSERT(mutex_is_locked(&root->fs_info->delete_unused_bgs_mutex)); + ret = btrfs_can_relocate(extent_root, chunk_offset); if (ret) return -ENOSPC; @@ -2814,13 +2828,18 @@ again: key.type = BTRFS_CHUNK_ITEM_KEY; while (1) { + mutex_lock(&root->fs_info->delete_unused_bgs_mutex); ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0); - if (ret < 0) + if (ret < 0) { + mutex_unlock(&root->fs_info->delete_unused_bgs_mutex); goto error; + } BUG_ON(ret == 0); /* Corruption */ ret = btrfs_previous_item(chunk_root, path, key.objectid, key.type); + if (ret) + mutex_unlock(&root->fs_info->delete_unused_bgs_mutex); if (ret < 0) goto error; if (ret > 0) @@ -2843,6 +2862,7 @@ again: else BUG_ON(ret); } + mutex_unlock(&root->fs_info->delete_unused_bgs_mutex); if (found_key.offset == 0) break; @@ -3299,9 +3319,12 @@ again: goto error; } + mutex_lock(&fs_info->delete_unused_bgs_mutex); ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0); - if (ret < 0) + if (ret < 0) { + mutex_unlock(&fs_info->delete_unused_bgs_mutex); goto error; + } /* * this shouldn't happen, it means the last relocate @@ -3313,6 +3336,7 @@ again: ret = btrfs_previous_item(chunk_root, path, 0, BTRFS_CHUNK_ITEM_KEY); if (ret) { + mutex_unlock(&fs_info->delete_unused_bgs_mutex); ret = 0; break; } @@ -3321,8 +3345,10 @@ again: slot = path->slots[0]; btrfs_item_key_to_cpu(leaf, &found_key, slot); - if (found_key.objectid != key.objectid) + if (found_key.objectid != key.objectid) { + mutex_unlock(&fs_info->delete_unused_bgs_mutex); break; + } chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk); @@ -3335,10 +3361,13 @@ again: ret = should_balance_chunk(chunk_root, leaf, chunk, found_key.offset); btrfs_release_path(path); - if (!ret) + if (!ret) { + mutex_unlock(&fs_info->delete_unused_bgs_mutex); goto loop; + } if (counting) { + mutex_unlock(&fs_info->delete_unused_bgs_mutex); spin_lock(&fs_info->balance_lock); bctl->stat.expected++; spin_unlock(&fs_info->balance_lock); @@ -3348,6 +3377,7 @@ again: ret = btrfs_relocate_chunk(chunk_root, found_key.objectid, found_key.offset); + mutex_unlock(&fs_info->delete_unused_bgs_mutex); if (ret && ret != -ENOSPC) goto error; if (ret == -ENOSPC) { @@ -4087,11 +4117,16 @@ again: key.type = BTRFS_DEV_EXTENT_KEY; do { + mutex_lock(&root->fs_info->delete_unused_bgs_mutex); ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); - if (ret < 0) + if (ret < 0) { + mutex_unlock(&root->fs_info->delete_unused_bgs_mutex); goto done; + } ret = btrfs_previous_item(root, path, 0, key.type); + if (ret) + mutex_unlock(&root->fs_info->delete_unused_bgs_mutex); if (ret < 0) goto done; if (ret) { @@ -4105,6 +4140,7 @@ again: btrfs_item_key_to_cpu(l, &key, path->slots[0]); if (key.objectid != device->devid) { + mutex_unlock(&root->fs_info->delete_unused_bgs_mutex); btrfs_release_path(path); break; } @@ -4113,6 +4149,7 @@ again: length = btrfs_dev_extent_length(l, dev_extent); if (key.offset + length <= new_size) { + mutex_unlock(&root->fs_info->delete_unused_bgs_mutex); btrfs_release_path(path); break; } @@ -4122,6 +4159,7 @@ again: btrfs_release_path(path); ret = btrfs_relocate_chunk(root, chunk_objectid, chunk_offset); + mutex_unlock(&root->fs_info->delete_unused_bgs_mutex); if (ret && ret != -ENOSPC) goto done; if (ret == -ENOSPC) |