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@xxxxxxx>
>>
>> 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@xxxxxxx>
>> Cc: stable@xxxxxxxxxxxxxxx
>> Signed-off-by: Changwei Ge <ge.changwei@xxxxxxx>
>> ---
>> 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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