lkml.org 
[lkml]   [2012]   [Jun]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v4 1/2] aio: make kiocb->private NUll in init_sync_kiocb()
On 06/29/2012 05:22 PM, Joel Becker wrote:
> On Thu, Jun 28, 2012 at 03:39:56PM -0700, Andrew Morton wrote:
>> On Wed, 27 Jun 2012 17:09:54 +0800
>> Junxiao Bi <junxiao.bi@oracle.com> wrote:
>>
>>> Ocfs2 uses kiocb.*private as a flag of unsigned long size. In
>>> commit a11f7e6 ocfs2: serialize unaligned aio, the unaligned
>>> io flag is involved in it to serialize the unaligned aio. As
>>> *private is not initialized in init_sync_kiocb() of do_sync_write(),
>>> this unaligned io flag may be unexpectly set in an aligned dio.
>>> And this will cause OCFS2_I(inode)->ip_unaligned_aio decreased
>>> to -1 in ocfs2_dio_end_io(), thus the following unaligned dio
>>> will hang forever at ocfs2_aiodio_wait() in ocfs2_file_aio_write().
>>>
>>> Signed-off-by: Junxiao Bi <junxiao.bi@oracle.com>
>>> Cc: stable@vger.kernel.org
>>> Acked-by: Jeff Moyer <jmoyer@redhat.com>
>>> Acked-by: Joel Becker <jlbec@evilplan.org>
>>> ---
>>> include/linux/aio.h | 1 +
>>> 1 file changed, 1 insertion(+)
>>>
>>> diff --git a/include/linux/aio.h b/include/linux/aio.h
>>> index 2314ad8..b1a520e 100644
>>> --- a/include/linux/aio.h
>>> +++ b/include/linux/aio.h
>>> @@ -140,6 +140,7 @@ struct kiocb {
>>> (x)->ki_dtor = NULL; \
>>> (x)->ki_obj.tsk = tsk; \
>>> (x)->ki_user_data = 0; \
>>> + (x)->private = NULL; \
>>> } while (0)
>>>
>>> #define AIO_RING_MAGIC 0xa10a10a1
>> hm, that code is rather cruddy. Pointless macromania.
> Agreed.
>
>> If we do this:
>>
>> static inline void init_sync_kiocb(struct kiocb *kiocb, struct file *filp)
>> {
>> *kiocb = (struct kiocb) {
>> .ki_users = 1,
>> .ki_key = KIOCB_SYNC_KEY,
>> .ki_filp = filp,
>> .ki_obj.tsk = current,
>> };
>> }
>>
>> then fs/read_write.o's .text is shrunk from 9857 bytes to 9714, which
>> is rather a lot.
>>
>> But that's all rather irrelevant to your bugfix.
> I like your solution. Junxiao, if you send me that version, I'd
> be happy to take it.
Joel, since Andrew will feed his cleanup patch later on. Please help
merge my patches. Though it is covered by the cleanup patch, but I think
it's useful to merge it, at least we can see from the git log this is
for an ocfs2 hang bug.
>
> Joel
>



\
 
 \ /
  Last update: 2012-06-29 13:21    [W:0.061 / U:0.272 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site