diff options
Diffstat (limited to 'fs/btrfs/disk-io.c')
| -rw-r--r-- | fs/btrfs/disk-io.c | 41 |
1 files changed, 40 insertions, 1 deletions
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index 3f43bfea3684..a9aadb2ad525 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -1751,6 +1751,7 @@ static int cleaner_kthread(void *arg) { struct btrfs_root *root = arg; int again; + struct btrfs_trans_handle *trans; do { again = 0; @@ -1772,7 +1773,6 @@ static int cleaner_kthread(void *arg) } btrfs_run_delayed_iputs(root); - btrfs_delete_unused_bgs(root->fs_info); again = btrfs_clean_one_deleted_snapshot(root); mutex_unlock(&root->fs_info->cleaner_mutex); @@ -1781,6 +1781,16 @@ static int cleaner_kthread(void *arg) * needn't do anything special here. */ btrfs_run_defrag_inodes(root->fs_info); + + /* + * Acquires fs_info->delete_unused_bgs_mutex to avoid racing + * with relocation (btrfs_relocate_chunk) and relocation + * acquires fs_info->cleaner_mutex (btrfs_relocate_block_group) + * after acquiring fs_info->delete_unused_bgs_mutex. So we + * can't hold, nor need to, fs_info->cleaner_mutex when deleting + * unused block groups. + */ + btrfs_delete_unused_bgs(root->fs_info); sleep: if (!try_to_freeze() && !again) { set_current_state(TASK_INTERRUPTIBLE); @@ -1789,6 +1799,34 @@ sleep: __set_current_state(TASK_RUNNING); } } while (!kthread_should_stop()); + + /* + * Transaction kthread is stopped before us and wakes us up. + * However we might have started a new transaction and COWed some + * tree blocks when deleting unused block groups for example. So + * make sure we commit the transaction we started to have a clean + * shutdown when evicting the btree inode - if it has dirty pages + * when we do the final iput() on it, eviction will trigger a + * writeback for it which will fail with null pointer dereferences + * since work queues and other resources were already released and + * destroyed by the time the iput/eviction/writeback is made. + */ + trans = btrfs_attach_transaction(root); + if (IS_ERR(trans)) { + if (PTR_ERR(trans) != -ENOENT) + btrfs_err(root->fs_info, + "cleaner transaction attach returned %ld", + PTR_ERR(trans)); + } else { + int ret; + + ret = btrfs_commit_transaction(trans, root); + if (ret) + btrfs_err(root->fs_info, + "cleaner open transaction commit returned %d", + ret); + } + return 0; } @@ -2492,6 +2530,7 @@ int open_ctree(struct super_block *sb, spin_lock_init(&fs_info->unused_bgs_lock); rwlock_init(&fs_info->tree_mod_log_lock); mutex_init(&fs_info->unused_bg_unpin_mutex); + mutex_init(&fs_info->delete_unused_bgs_mutex); mutex_init(&fs_info->reloc_mutex); mutex_init(&fs_info->delalloc_root_mutex); seqlock_init(&fs_info->profiles_lock); |