linux-ext4 - [PATCH] ext4: fix fencepost in s_first_meta

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Message-Id: <20170215062641.17620-1-tytso@mit.edu>
Date:   Wed, 15 Feb 2017 01:26:41 -0500
From:   Theodore Ts'o <tytso@....edu>
To:     Ext4 Developers List <linux-ext4@...r.kernel.org>
Cc:     Theodore Ts'o <tytso@....edu>, stable@...r.kernel.org
Subject: [PATCH] ext4: fix fencepost in s_first_meta_bg validation

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@....edu>
Cc: stable@...r.kernel.org
---
 fs/ext4/super.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index dde14a7ac6d7..a673558fe5f8 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3860,7 +3860,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 	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)",
-- 
2.11.0.rc0.7.gbe5a750