Messages in this thread | | | Date | Tue, 3 Jul 2012 23:13:55 -0700 | From | Joel Becker <> | Subject | Re: [PATCH v4 1/2] aio: make kiocb->private NUll in init_sync_kiocb() |
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On Fri, Jun 29, 2012 at 06:49:43PM +0800, Junxiao Bi wrote: > 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.
Yes, I'll be pulling it.
Joel
> > > > Joel > > >
--
"In the room the women come and go Talking of Michaelangelo."
http://www.jlbec.org/ jlbec@evilplan.org
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