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From:   Vasily Averin <vvs@virtuozzo.com>
Subject: [PATCH 4/7] ext4 resize: brelse() cleanup in add_new_gdb_meta_bg()
To:     linux-ext4@vger.kernel.org, Theodore Ts'o <tytso@mit.edu>
Cc:     Andreas Dilger <adilger.kernel@dilger.ca>,
        linux-kernel@vger.kernel.org,
        Yongqiang Yang <xiaoqiangnk@gmail.com>,
        Yongqiang Yang <yangyongqiang01@baidu.com>
Message-ID: <8807a471-2331-276d-1b72-dce55ea7a1cf@virtuozzo.com>
Date:   Mon, 29 Oct 2018 18:25:22 +0300
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gdb_bh must be released in case of errors before update of s_group_desc
but it must not be released after update of group descriptors
because in this case bh can be used later.

Fixes 01f795f9e0d6 ("ext4: add online resizing support for meta_bg ...")
#? cc: stable@vger.kernel.org # 3.7+

Signed-off-by: Vasily Averin <vvs@openvz.org>
---
 fs/ext4/resize.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
index ff17480e8613..ff8389ac4769 100644
--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c
@@ -923,6 +923,7 @@ static int add_new_gdb_meta_bg(struct super_block *sb,
 				     sizeof(struct buffer_head *),
 				     GFP_NOFS);
 	if (!n_group_desc) {
+		brelse(gdb_bh);
 		err = -ENOMEM;
 		ext4_warning(sb, "not enough memory for %lu groups",
 			     gdb_num + 1);
@@ -938,8 +939,6 @@ static int add_new_gdb_meta_bg(struct super_block *sb,
 	kvfree(o_group_desc);
 	BUFFER_TRACE(gdb_bh, "get_write_access");
 	err = ext4_journal_get_write_access(handle, gdb_bh);
-	if (unlikely(err))
-		brelse(gdb_bh);
 	return err;
 }
 
-- 
2.17.1