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(), 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@HK2PR06MB045... 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 ---

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

--- 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; _