From 29aa30167a0a2e6045a0d6d2e89d8168132333d5 Mon Sep 17 00:00:00 2001
From: Changwei Ge <ge.changwei@h3c.com>
Date: Fri, 2 Nov 2018 15:48:15 -0700
Subject: [PATCH] ocfs2: fix a misuse a of brelse after failing
 ocfs2_check_dir_entry
Git-commit: 29aa30167a0a2e6045a0d6d2e89d8168132333d5
Patch-mainline: v4.20-rc1
References: bsc#1117817

Somehow, file system metadata was corrupted, which causes
ocfs2_check_dir_entry() to fail in function ocfs2_dir_foreach_blk_el().

According to the original design intention, if above happens we should
skip the problematic block and continue to retrieve dir entry.  But
there is obviouse misuse of brelse around related code.

After failure of ocfs2_check_dir_entry(), current code just moves to
next position and uses the problematic buffer head again and again
during which the problematic buffer head is released for multiple times.
I suppose, this a serious issue which is long-lived in ocfs2.  This may
cause other file systems which is also used in a the same host insane.

So we should also consider about bakcporting this patch into linux
-stable.

Link: http://lkml.kernel.org/r/HK2PR06MB045211675B43EED794E597B6D56E0@HK2PR06MB0452.apcprd06.prod.outlook.com
Signed-off-by: Changwei Ge <ge.changwei@h3c.com>
Suggested-by: Changkuo Shi <shi.changkuo@h3c.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Joseph Qi <jiangqi903@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Jan Kara <jack@suse.cz>

---
 fs/ocfs2/dir.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/fs/ocfs2/dir.c b/fs/ocfs2/dir.c
index b048d4fa3959..c121abbdfc7d 100644
--- a/fs/ocfs2/dir.c
+++ b/fs/ocfs2/dir.c
@@ -1897,8 +1897,7 @@ static int ocfs2_dir_foreach_blk_el(struct inode *inode,
 				/* On error, skip the f_pos to the
 				   next block. */
 				ctx->pos = (ctx->pos | (sb->s_blocksize - 1)) + 1;
-				brelse(bh);
-				continue;
+				break;
 			}
 			if (le64_to_cpu(de->inode)) {
 				unsigned char d_type = DT_UNKNOWN;
-- 
2.16.4