From: Andreas Gruenbacher <agruenba@redhat.com>
Date: Mon, 5 Mar 2018 13:18:25 +0000 (-0700)
Subject: gfs2: Fixes to "Implement iomap for block_map" (2)
X-Git-Tag: v4.15.11~99
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ae53e57f59115cc5f08031e7e5b14e6b057e4323;p=thirdparty%2Fkernel%2Fstable.git

gfs2: Fixes to "Implement iomap for block_map" (2)

commit 3b5da96e4585a2788da6a07619bda3518d76eb30 upstream.

It turns out that commit 3229c18c0d6b2 'Fixes to "Implement iomap for
block_map"' introduced another bug in gfs2_iomap_begin that can cause
gfs2_block_map to set bh->b_size of an actual buffer to 0.  This can
lead to arbitrary incorrect behavior including crashes or disk
corruption.  Revert the incorrect part of that commit.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/fs/gfs2/bmap.c b/fs/gfs2/bmap.c
index 76de441b4d9fd..f13e986696f7b 100644
--- a/fs/gfs2/bmap.c
+++ b/fs/gfs2/bmap.c
@@ -811,9 +811,6 @@ do_alloc:
 			iomap->length = hole_size(inode, lblock, &mp);
 		else
 			iomap->length = size - pos;
-	} else {
-		if (height <= ip->i_height)
-			iomap->length = hole_size(inode, lblock, &mp);
 	}
 	goto out_release;
 }