+ ocfs2-fix-a-misuse-a-of-brelse-after-failing-ocfs2_check_dir_entry.patch added to -mm tree

+ ocfs2-fix-a-misuse-a-of-brelse-after-failing-ocfs2_check_dir_entry.patch added to -mm tree

[akpm]

The patch titled
     Subject: ocfs2: fix a misuse a of brelse after failing ocfs2_check_dir_entry
has been added to the -mm tree.  Its filename is
     ocfs2-fix-a-misuse-a-of-brelse-after-failing-ocfs2_check_dir_entry.patch

This patch should soon appear at
    http://ozlabs.org/~akpm/mmots/broken-out/ocfs2-fix-a-misuse-a-of-brelse-after-failing-ocfs2_check_dir_entry.patch
and later at
    http://ozlabs.org/~akpm/mmotm/broken-out/ocfs2-fix-a-misuse-a-of-brelse-after-failing-ocfs2_check_dir_entry.patch

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------------------------------------------------------
From: Changwei Ge <ge.changwei@h3c.com>
Subject: ocfs2: fix a misuse a of brelse after failing ocfs2_check_dir_entry

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(), currunt 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>
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>
---

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

diff -puN fs/ocfs2/dir.c~ocfs2-fix-a-misuse-a-of-brelse-after-failing-ocfs2_check_dir_entry fs/ocfs2/dir.c
--- a/fs/ocfs2/dir.c~ocfs2-fix-a-misuse-a-of-brelse-after-failing-ocfs2_check_dir_entry
+++ a/fs/ocfs2/dir.c
@@ -1897,8 +1897,7 @@ static int ocfs2_dir_foreach_blk_el(stru
 				/* 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;
_

Patches currently in -mm which might be from ge.changwei@h3c.com are

ocfs2-fix-a-misuse-a-of-brelse-after-failing-ocfs2_check_dir_entry.patch
ocfs2-dont-put-and-assign-null-to-bh-allocated-outside.patch
ocfs2-dont-use-iocb-when-eiocbqueued-returns.patch