2013/2/6 Steve French <smfrench@xxxxxxxxx>:
> Forwarding to the current cifs development mailing list
>
>
> ---------- Forwarded message ----------
> From: <jiang.biao2@xxxxxxxxxx>
> Date: Wed, Feb 6, 2013 at 12:26 AM
> Subject: [PATCH] cifs: bugfix for unreclaimed writeback pages in
> cifs_writev_requeue()
> To: Steve French <sfrench@xxxxxxxxx>, linux-cifs-client@xxxxxxxxxxxxxxx
>
>
>
> This patch applies to the kernel version of linux-3.8-rc6.
>
> Pages get the PG_writeback flag set before cifs sends its request
> to SMB server
> in cifs_writepages(), if the SMB service goes down, cifs may try
> to recommit the
> writing requests in cifs_writev_requeue(). However, it does not
> clean its PG_writeback
> flag and relaimed the pages even if it fails again in
> cifs_writev_requeue(), which
> may lead to the hanging of the processes accessing the cifs
> directory. This patch
> just cleans the PG_writeback flags and reclaims the pages under
> that circumstances.
>
> Steps to reproduce the bug(trying serveral times may trigger the issue):
> 1.Write from cifs client continuously.(e.g dd if=/dev/zero of=<cifs file>)
> 2.Stop SMB service from server.(e.g service smb stop)
> 3.Wait for two minutes， and then start SMB service from
> server.(e.g service smb start)
> 4.The processes which are accessing cifs directory may hang up.
>
> Signed-off-by: Ouyang Maochun <ouyang.maochun@xxxxxxxxxx>
> Signed-off-by: Jiang Yong <jian.yong5@xxxxxxxxxx>
> Tested-by: Zhang Xianwei <zhang.xianwei8@xxxxxxxxxx>
> Reviewed-by: Wang Liang <wang.liang82@xxxxxxxxxx>
> Reviewed-by: Cai Qu <cai.qu@xxxxxxxxxx>
> Reviewed-by: Jiang Biao <jiang.biao2@xxxxxxxxxx>
>
> diff -uprN linux-3.8-rc6/fs/cifs/cifssmb.c linux-3.8-rc6_new/fs/cifs/cifssmb.c
> --- linux-3.8-rc6/fs/cifs/cifssmb.c 2013-02-01 09:08:14.000000000 +0800
> +++ linux-3.8-rc6_new/fs/cifs/cifssmb.c 2013-02-04
> 15:44:09.869254397 +0800
> @@ -1909,8 +1909,11 @@ cifs_writev_requeue(struct cifs_writedat
> } while (rc == -EAGAIN);
>
> for (i = 0; i < wdata->nr_pages; i++) {
> - if (rc != 0)
> + if (rc != 0){
> SetPageError(wdata->pages[i]);
> + end_page_writeback(wdata->pages[i]);
> + page_cache_release(wdata->pages[i]);
> + }
I think we should do end_page_writeback(wdata->pages[i]) and
page_cache_release(wdata->pages[i]) regardless whether rc is 0 or not
(we are doing the same things in cifs_writev_complete now). Thoughts?
> unlock_page(wdata->pages[i]);
> }
>
>
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>
>
> --
> Thanks,
>
> Steve
> --
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--
Best regards,
Pavel Shilovsky.
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