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authorFilipe Manana <fdmanana@suse.com>2018-06-11 19:24:28 +0100
committerDavid Sterba <dsterba@suse.com>2018-08-23 17:37:26 +0200
commitd4682ba03ef618b6ef4be7cedc7aacaf505d3a58 (patch)
tree5700c2336b2b53118c4869c447f084023ab8555e /fs/btrfs/tree-log.h
parent8ecebf4d767e2307a946c8905278d6358eda35c3 (diff)
Btrfs: sync log after logging new name
When we add a new name for an inode which was logged in the current transaction, we update the inode in the log so that its new name and ancestors are added to the log. However when we do this we do not persist the log, so the changes remain in memory only, and as a consequence, any ancestors that were created in the current transaction are updated such that future calls to btrfs_inode_in_log() return true. This leads to a subsequent fsync against such new ancestor directories returning immediately, without persisting the log, therefore after a power failure the new ancestor directories do not exist, despite fsync being called against them explicitly. Example: $ mkfs.btrfs -f /dev/sdb $ mount /dev/sdb /mnt $ mkdir /mnt/A $ mkdir /mnt/B $ mkdir /mnt/A/C $ touch /mnt/B/foo $ xfs_io -c "fsync" /mnt/B/foo $ ln /mnt/B/foo /mnt/A/C/foo $ xfs_io -c "fsync" /mnt/A <power failure> After the power failure, directory "A" does not exist, despite the explicit fsync on it. Instead of fixing this by changing the behaviour of the explicit fsync on directory "A" to persist the log instead of doing nothing, make the logging of the new file name (which happens when creating a hard link or renaming) persist the log. This approach not only is simpler, not requiring addition of new fields to the inode in memory structure, but also gives us the same behaviour as ext4, xfs and f2fs (possibly other filesystems too). A test case for fstests follows soon. Fixes: 12fcfd22fe5b ("Btrfs: tree logging unlink/rename fixes") Reported-by: Vijay Chidambaram <vvijay03@gmail.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs/tree-log.h')
-rw-r--r--fs/btrfs/tree-log.h10
1 files changed, 9 insertions, 1 deletions
diff --git a/fs/btrfs/tree-log.h b/fs/btrfs/tree-log.h
index 122e68b89a5a..7ab9bb88a639 100644
--- a/fs/btrfs/tree-log.h
+++ b/fs/btrfs/tree-log.h
@@ -71,8 +71,16 @@ void btrfs_record_unlink_dir(struct btrfs_trans_handle *trans,
int for_rename);
void btrfs_record_snapshot_destroy(struct btrfs_trans_handle *trans,
struct btrfs_inode *dir);
+/* Return values for btrfs_log_new_name() */
+enum {
+ BTRFS_DONT_NEED_TRANS_COMMIT,
+ BTRFS_NEED_TRANS_COMMIT,
+ BTRFS_DONT_NEED_LOG_SYNC,
+ BTRFS_NEED_LOG_SYNC,
+};
int btrfs_log_new_name(struct btrfs_trans_handle *trans,
struct btrfs_inode *inode, struct btrfs_inode *old_dir,
- struct dentry *parent);
+ struct dentry *parent,
+ bool sync_log, struct btrfs_log_ctx *ctx);
#endif