From b26384dc52edba2f5fcc2b38eccc98e1f44bb379 Mon Sep 17 00:00:00 2001
From: Eric Sandeen <sandeen@sandeen.net>
Date: Wed, 25 Mar 2015 14:54:25 +1100
Subject: xfs: fix NULL pointer dereference in xfs_filestream_lookup_ag()

If xfs_filestream_get_parent() fails, we have a null pip,
goto out, and attempt to IRELE(NULL).  This causes a null
pointer dereference and BUG().

Fix this by directly returning NULLAGNUMBER in this case.

Reported-by: Adrien Nader <adrien@notk.org>
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

diff --git a/fs/xfs/xfs_filestream.c b/fs/xfs/xfs_filestream.c
index a2e86e8..8f9f854 100644
--- a/fs/xfs/xfs_filestream.c
+++ b/fs/xfs/xfs_filestream.c
@@ -322,7 +322,7 @@ xfs_filestream_lookup_ag(
 
 	pip = xfs_filestream_get_parent(ip);
 	if (!pip)
-		goto out;
+		return NULLAGNUMBER;
 
 	mru = xfs_mru_cache_lookup(mp->m_filestream, pip->i_ino);
 	if (mru) {
-- 
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