[Ocfs2-devel] [PATCH] ocfs2: free up write context when direct IO failed

[Wengang Wang]

On 2018/11/1 19:51, Junxiao Bi wrote:
> On 11/02/2018 05:15 AM, Wengang Wang wrote:
>
>> The write context should also be freed even when direct IO failed.
>> Otherwise a memory leak is introduced and entries remain in
>> oi->ip_unwritten_list causing the following BUG later in unlink path:
>>
>> ERROR: bug expression: !list_empty(&oi->ip_unwritten_list)
>> ERROR: Clear inode of 215043, inode has unwritten extents
>> ...
>> Call Trace:
>> ? __set_current_blocked+0x42/0x68
>> ocfs2_evict_inode+0x91/0x6a0 [ocfs2]
>> ? bit_waitqueue+0x40/0x33
>> evict+0xdb/0x1af
>> iput+0x1a2/0x1f7
>> do_unlinkat+0x194/0x28f
>> SyS_unlinkat+0x1b/0x2f
>> do_syscall_64+0x79/0x1ae
>> entry_SYSCALL_64_after_hwframe+0x151/0x0
>>
>> Signed-off-by: Wengang Wang <wen.gang.wang at oracle.com>
>> ---
>>   fs/ocfs2/aops.c | 11 +++++++++--
>>   1 file changed, 9 insertions(+), 2 deletions(-)
>>
>> diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
>> index 302cd7c..a87ca42d 100644
>> --- a/fs/ocfs2/aops.c
>> +++ b/fs/ocfs2/aops.c
>> @@ -2412,8 +2412,15 @@ static int ocfs2_dio_end_io(struct kiocb *iocb,
>>       /* this io's submitter should not have unlocked this before we 
>> could */
>>       BUG_ON(!ocfs2_iocb_is_rw_locked(iocb));
>>   -    if (bytes > 0 && private)
>> -        ret = ocfs2_dio_end_io_write(inode, private, offset, bytes);
>> +    if (private) {
>> +        if (bytes > 0) {
>> +            ret = ocfs2_dio_end_io_write(inode, private, offset,
>> +                             bytes);
>> +        } else {
>> +            mlog(ML_ERROR, "Direct IO failed, free write ctx");
> Is it useful to leave the "bytes" value here? It could be some error 
> code.
>
That would be error come from below file system, but we can log it.
Will send v2 to add "bytes".

thanks,
wengang
> Thanks,
> Junxiao.
>> + ocfs2_dio_free_write_ctx(inode, private);
>> +        }
>> +    }
>>         ocfs2_iocb_clear_rw_locked(iocb);
>