From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-yw0-f46.google.com ([209.85.213.46]:47970 "EHLO mail-yw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751434Ab1FMP4l convert rfc822-to-8bit (ORCPT ); Mon, 13 Jun 2011 11:56:41 -0400 Received: by ywe9 with SMTP id 9so2069994ywe.19 for ; Mon, 13 Jun 2011 08:56:40 -0700 (PDT) In-Reply-To: <9203fc2b8c4edc9fcc695e2b0ccd7993727935bf.1307921138.git.rees@umich.edu> References: <9203fc2b8c4edc9fcc695e2b0ccd7993727935bf.1307921138.git.rees@umich.edu> Date: Mon, 13 Jun 2011 11:56:40 -0400 Message-ID: Subject: Re: [PATCH 18/34] pnfsblock: allow use of PG_owner_priv_1 flag From: Fred Isaman To: Jim Rees Cc: linux-nfs@vger.kernel.org, peter honeyman Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-nfs-owner@vger.kernel.org List-ID: MIME-Version: 1.0 On Sun, Jun 12, 2011 at 7:44 PM, Jim Rees wrote: > From: Fred Isaman > > There is currently no good way for pnfs to communicate problems.  For > example - the linux read code first tries to do readahead through > nfs_readpages. Failure there is ignored, and it will later call > nfs_readpage.  Failure there is also ignored, except that the lack of > PG_uptodate is communicated back via -EIO. > > With pnfs, it would be useful to be able to communicate to > nfs_readpage that direct disk IO failed on readahead, and that it > should failover to using the MDS. > > Making the page flag PG_owner_priv_1 available as PG_pnfserr is one > way to do so. (An alternative would be to embed this in the layout, > but then pg_test can't easily access the info.) > > This may be better as generic pnfs code, in which case it should be > put in pnfs.h, or even page-flags.h > > Signed-off-by: Fred Isaman > Signed-off-by: Benny Halevy > --- The error handling has changed a bit since this was written. It is currently very course grained for simplicity reasons. Is there any reason you can't do similarly, and just use NFS_LAYOUT_{RW|RO}_FAILED in lo->plh_flags? Fred >  fs/nfs/blocklayout/blocklayout.h |    5 +++++ >  1 files changed, 5 insertions(+), 0 deletions(-) > > diff --git a/fs/nfs/blocklayout/blocklayout.h b/fs/nfs/blocklayout/blocklayout.h > index 21fa21c..293f009 100644 > --- a/fs/nfs/blocklayout/blocklayout.h > +++ b/fs/nfs/blocklayout/blocklayout.h > @@ -35,6 +35,11 @@ >  #include >  #include "../pnfs.h" > > +#define PG_pnfserr PG_owner_priv_1 > +#define PagePnfsErr(page)      test_bit(PG_pnfserr, &(page)->flags) > +#define SetPagePnfsErr(page)   set_bit(PG_pnfserr, &(page)->flags) > +#define ClearPagePnfsErr(page) clear_bit(PG_pnfserr, &(page)->flags) > + >  struct block_mount_id { >        spinlock_t                      bm_lock;    /* protects list */ >        struct list_head                bm_devlist; /* holds pnfs_block_dev */ > -- > 1.7.4.1 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-nfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at  http://vger.kernel.org/majordomo-info.html >