Messages in this thread | | | Date | Fri, 29 Jun 2012 18:49:43 +0800 | From | Junxiao Bi <> | Subject | Re: [PATCH v4 1/2] aio: make kiocb->private NUll in init_sync_kiocb() |
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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 >
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