releases/4.9.31/xfs-bad-assertion-for-delalloc-an-extent-that-start-at-i_size.patch

From 892d2a5f705723b2cb488bfb38bcbdcf83273184 Mon Sep 17 00:00:00 2001
From: Zorro Lang <zlang@redhat.com>
Date: Mon, 15 May 2017 08:40:02 -0700
Subject: xfs: bad assertion for delalloc an extent that start at i_size

From: Zorro Lang <zlang@redhat.com>

commit 892d2a5f705723b2cb488bfb38bcbdcf83273184 upstream.

By run fsstress long enough time enough in RHEL-7, I find an
assertion failure (harder to reproduce on linux-4.11, but problem
is still there):

  XFS: Assertion failed: (iflags & BMV_IF_DELALLOC) != 0, file: fs/xfs/xfs_bmap_util.c

The assertion is in xfs_getbmap() funciton:

  if (map[i].br_startblock == DELAYSTARTBLOCK &&
-->   map[i].br_startoff <= XFS_B_TO_FSB(mp, XFS_ISIZE(ip)))
          ASSERT((iflags & BMV_IF_DELALLOC) != 0);

When map[i].br_startoff == XFS_B_TO_FSB(mp, XFS_ISIZE(ip)), the
startoff is just at EOF. But we only need to make sure delalloc
extents that are within EOF, not include EOF.

Signed-off-by: Zorro Lang <zlang@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 fs/xfs/xfs_bmap_util.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/fs/xfs/xfs_bmap_util.c
+++ b/fs/xfs/xfs_bmap_util.c
@@ -722,7 +722,7 @@ xfs_getbmap(
 			 * extents.
 			 */
 			if (map[i].br_startblock == DELAYSTARTBLOCK &&
-			    map[i].br_startoff <= XFS_B_TO_FSB(mp, XFS_ISIZE(ip)))
+			    map[i].br_startoff < XFS_B_TO_FSB(mp, XFS_ISIZE(ip)))
 				ASSERT((iflags & BMV_IF_DELALLOC) != 0);
 
                         if (map[i].br_startblock == HOLESTARTBLOCK &&