btrfs: fix missing semaphore unlock in btrfs_sync_file

commit fa5fc463db54f86656fef2867a83013e0232f27b upstream.

Ordered ops are started twice in sync file, once outside of inode mutex
and once inside, taking the dio semaphore. There was one error path
missing the semaphore unlock.

Fixes: 0e9d2c534def8 ("Btrfs: fix rare chances for data loss when doing a fast fsync")
CC: stable@vger.kernel.org # 4.19+
Signed-off-by: Robbie Ko <robbieko@synology.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
[ add changelog ]
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index e1c2aa46cb0c9e652425440efef599aff1699304..3cfbccacef7fd035c1fe1b55a24a130bb2071d1e 100644 (file)
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -2137,6 +2137,7 @@ int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
         */
        ret = start_ordered_ops(inode, start, end);
        if (ret) {
+               up_write(&BTRFS_I(inode)->dio_sem);
                inode_unlock(inode);
                goto out;
        }