[PATCH 4.4 30/30] ext4: fix fencepost in s_first_meta_bg validation

Greg Kroah-Hartman
2017-03-24T18:05:51Z

From: Theodore Ts'o <tytso@mit.edu>

commit 2ba3e6e8afc9b6188b471f27cf2b5e3cf34e7af2 upstream.

It is OK for s_first_meta_bg to be equal to the number of block group
descriptor blocks. (It rarely happens, but it shouldn't cause any
problems.)

https://bugzilla.kernel.org/show_bug.cgi?id=194567

Fixes: 3a4b77cd47bb837b8557595ec7425f281f2ca1fe
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
fs/ext4/super.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3666,7 +3666,7 @@ static int ext4_fill_super(struct super_
db_count = (sbi->s_groups_count + EXT4_DESC_PER_BLOCK(sb) - 1) /
EXT4_DESC_PER_BLOCK(sb);
if (ext4_has_feature_meta_bg(sb)) {
- if (le32_to_cpu(es->s_first_meta_bg) >= db_count) {
+ if (le32_to_cpu(es->s_first_meta_bg) > db_count) {
ext4_msg(sb, KERN_WARNING,
"first meta block group too large: %u "
"(group descriptor block count %u)",