[PATCH] btrfs: Add missing skip-lock for locks

[Edward Adam Davis]

The commit 939b656bc8ab missing a skip-lock in btrfs_sync_file,
it cause syzbot report WARNING: bad unlock balance in btrfs_direct_write.

Fixes: 939b656bc8ab ("btrfs: fix corruption after buffer fault in during direct IO append write")
Reported-and-tested-by: syzbot+7dbbb74af6291b5a5a8b@xxxxxxxxxxxxxxxxxxxxxxxxx
Closes: https://syzkaller.appspot.com/bug?extid=7dbbb74af6291b5a5a8b
Signed-off-by: Edward Adam Davis <eadavis@xxxxxx>
---
 fs/btrfs/file.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 9f10a9f23fcc..9914419f3b7d 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -1868,7 +1868,10 @@ int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
 
 out_release_extents:
 	btrfs_release_log_ctx_extents(&ctx);
-	btrfs_inode_unlock(inode, BTRFS_ILOCK_MMAP);
+	if (skip_ilock)
+		up_write(&inode->i_mmap_lock);
+	else
+		btrfs_inode_unlock(inode, BTRFS_ILOCK_MMAP);
 	goto out;
 }
 
-- 
2.43.0