[PATCH] locks: fix list insertion when lock is split in two

[Jeff Layton <jeff.layton@primarydata.com>]

Al reported that he had seen some LTP fcntl11 and fcntl21 test
failures since the merge window had opened.

In the case where we're splitting a lock in two, the current code
the new "left" lock in the incorrect spot. It's inserted just
before "right" when it should instead be inserted just before the
new lock.

When we add a new lock, set "fl" to that value so that we can
add "left" before it.

Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
---
 fs/locks.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/locks.c b/fs/locks.c
index 90b652ad306f..365c82e1b3a9 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -1107,6 +1107,7 @@ static int __posix_lock_file(struct inode *inode, struct file_lock *request, str
 		}
 		locks_copy_lock(new_fl, request);
 		locks_insert_lock_ctx(new_fl, &fl->fl_list);
+		fl = new_fl;
 		new_fl = NULL;
 	}
 	if (right) {
-- 
2.1.0