Hi Jun,
Thanks for looking into this, my code from Linux mainline is not looked like yours...
On 2018/11/10 14:36, piaojun wrote:
Hi Changwei,
On 2018/5/28 22:40, Changwei Ge wrote:
From: Changwei Ge ge.changwei@h3c.com
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.
Suggested-by: Changkuo Shi shi.changkuo@h3c.com Cc: stable@vger.kernel.org Signed-off-by: Changwei Ge ge.changwei@h3c.com
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 b048d4f..c121abb 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;I guess return is more appropriate than break here as it will cause double free buffer:
" ctx->pos = (ctx->pos | (sb->s_blocksize - 1)) + 1; brelse(bh); break; "
Linux mainline should not have 'brelse(bh)', could your please rebase your tree?
''' ccd979bdb (Mark Fasheh 2005-12-15 14:31:24 -0800 1897) /* On error, skip the f_pos to the ccd979bdb (Mark Fasheh 2005-12-15 14:31:24 -0800 1898) next block. */ 3704412bd (Al Viro 2013-05-22 21:06:00 -0400 1899) ctx->pos = (ctx->pos | (sb->s_blocksize - 1)) + 1; 29aa30167 (Changwei Ge 2018-11-02 15:48:15 -0700 1900) break; '''
" brelse(bh); bh = NULL; if (!persist && stored) break; "
Thanks, Jun
} if (le64_to_cpu(de->inode)) { unsigned char d_type = DT_UNKNOWN;
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