btrfs: do commit in sync_fs if there are pending changes
If a pending change is requested, it's not processed unless there is a
transaction commit about to happen, not even after sync or SYNC_FS
ioctl. For example a remount that toggles the inode_cache option will
not take effect after sync on a quiescent filesystem.
Signed-off-by: David Sterba <dsterba@suse.cz>
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 54bd91e..1da16d59 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -993,9 +993,17 @@
trans = btrfs_attach_transaction_barrier(root);
if (IS_ERR(trans)) {
/* no transaction, don't bother */
- if (PTR_ERR(trans) == -ENOENT)
- return 0;
- return PTR_ERR(trans);
+ if (PTR_ERR(trans) == -ENOENT) {
+ /*
+ * Exit unless we have some pending changes
+ * that need to go through commit
+ */
+ if (fs_info->pending_changes == 0)
+ return 0;
+ trans = btrfs_start_transaction(root, 0);
+ } else {
+ return PTR_ERR(trans);
+ }
}
return btrfs_commit_transaction(trans, root);
}