releases/5.6.14/gfs2-another-gfs2_walk_metadata-fix.patch

From c0bb334fa20ad338a0560d6d4daa3d96fd43685c Mon Sep 17 00:00:00 2001
From: Sasha Levin <sashal@kernel.org>
Date: Mon, 20 Apr 2020 19:42:04 +0200
Subject: gfs2: Another gfs2_walk_metadata fix

From: Andreas Gruenbacher <agruenba@redhat.com>

[ Upstream commit 566a2ab3c9005f62e784bd39022d58d34ef4365c ]

Make sure we don't walk past the end of the metadata in gfs2_walk_metadata: the
inode holds fewer pointers than indirect blocks.

Slightly clean up gfs2_iomap_get.

Fixes: a27a0c9b6a20 ("gfs2: gfs2_walk_metadata fix")
Cc: stable@vger.kernel.org # v5.3+
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/gfs2/bmap.c | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/fs/gfs2/bmap.c b/fs/gfs2/bmap.c
index 08f6fbb3655e2..31ed264356253 100644
--- a/fs/gfs2/bmap.c
+++ b/fs/gfs2/bmap.c
@@ -528,10 +528,12 @@ static int gfs2_walk_metadata(struct inode *inode, struct metapath *mp,
 
 		/* Advance in metadata tree. */
 		(mp->mp_list[hgt])++;
-		if (mp->mp_list[hgt] >= sdp->sd_inptrs) {
-			if (!hgt)
+		if (hgt) {
+			if (mp->mp_list[hgt] >= sdp->sd_inptrs)
+				goto lower_metapath;
+		} else {
+			if (mp->mp_list[hgt] >= sdp->sd_diptrs)
 				break;
-			goto lower_metapath;
 		}
 
 fill_up_metapath:
@@ -876,10 +878,9 @@ static int gfs2_iomap_get(struct inode *inode, loff_t pos, loff_t length,
 					ret = -ENOENT;
 					goto unlock;
 				} else {
-					/* report a hole */
 					iomap->offset = pos;
 					iomap->length = length;
-					goto do_alloc;
+					goto hole_found;
 				}
 			}
 			iomap->length = size;
@@ -933,8 +934,6 @@ static int gfs2_iomap_get(struct inode *inode, loff_t pos, loff_t length,
 	return ret;
 
 do_alloc:
-	iomap->addr = IOMAP_NULL_ADDR;
-	iomap->type = IOMAP_HOLE;
 	if (flags & IOMAP_REPORT) {
 		if (pos >= size)
 			ret = -ENOENT;
@@ -956,6 +955,9 @@ static int gfs2_iomap_get(struct inode *inode, loff_t pos, loff_t length,
 		if (pos < size && height == ip->i_height)
 			ret = gfs2_hole_size(inode, lblock, len, mp, iomap);
 	}
+hole_found:
+	iomap->addr = IOMAP_NULL_ADDR;
+	iomap->type = IOMAP_HOLE;
 	goto out;
 }
 
-- 
2.20.1