diff options
| -rw-r--r-- | fs/btrfs/btrfs_inode.h | 6 | ||||
| -rw-r--r-- | fs/btrfs/inode.c | 17 | ||||
| -rw-r--r-- | fs/btrfs/tree-log.c | 16 |
3 files changed, 39 insertions, 0 deletions
diff --git a/fs/btrfs/btrfs_inode.h b/fs/btrfs/btrfs_inode.h index fc25607304f2..6f5d07415dab 100644 --- a/fs/btrfs/btrfs_inode.h +++ b/fs/btrfs/btrfs_inode.h @@ -148,6 +148,12 @@ struct btrfs_inode { u64 last_unlink_trans; /* + * Track the transaction id of the last transaction used to create a + * hard link for the inode. This is used by the log tree (fsync). + */ + u64 last_link_trans; + + /* * Number of bytes outstanding that are going to need csums. This is * used in ENOSPC accounting. */ diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index d54bdef16d8d..b4129d9072ec 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -3658,6 +3658,21 @@ cache_index: * inode is not a directory, logging its parent unnecessarily. */ BTRFS_I(inode)->last_unlink_trans = BTRFS_I(inode)->last_trans; + /* + * Similar reasoning for last_link_trans, needs to be set otherwise + * for a case like the following: + * + * mkdir A + * touch foo + * ln foo A/bar + * echo 2 > /proc/sys/vm/drop_caches + * fsync foo + * <power failure> + * + * Would result in link bar and directory A not existing after the power + * failure. + */ + BTRFS_I(inode)->last_link_trans = BTRFS_I(inode)->last_trans; path->slots[0]++; if (inode->i_nlink != 1 || @@ -6597,6 +6612,7 @@ static int btrfs_link(struct dentry *old_dentry, struct inode *dir, if (err) goto fail; } + BTRFS_I(inode)->last_link_trans = trans->transid; d_instantiate(dentry, inode); ret = btrfs_log_new_name(trans, BTRFS_I(inode), NULL, parent, true, NULL); @@ -9123,6 +9139,7 @@ struct inode *btrfs_alloc_inode(struct super_block *sb) ei->index_cnt = (u64)-1; ei->dir_index = 0; ei->last_unlink_trans = 0; + ei->last_link_trans = 0; ei->last_log_commit = 0; spin_lock_init(&ei->lock); diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c index 013d0abcd46b..5baad9bebc62 100644 --- a/fs/btrfs/tree-log.c +++ b/fs/btrfs/tree-log.c @@ -5758,6 +5758,22 @@ static int btrfs_log_inode_parent(struct btrfs_trans_handle *trans, goto end_trans; } + /* + * If a new hard link was added to the inode in the current transaction + * and its link count is now greater than 1, we need to fallback to a + * transaction commit, otherwise we can end up not logging all its new + * parents for all the hard links. Here just from the dentry used to + * fsync, we can not visit the ancestor inodes for all the other hard + * links to figure out if any is new, so we fallback to a transaction + * commit (instead of adding a lot of complexity of scanning a btree, + * since this scenario is not a common use case). + */ + if (inode->vfs_inode.i_nlink > 1 && + inode->last_link_trans > last_committed) { + ret = -EMLINK; + goto end_trans; + } + while (1) { if (!parent || d_really_is_negative(parent) || sb != parent->d_sb) break; |