Return-Path: Received: from us-smtp-delivery-194.mimecast.com ([216.205.24.194]:31278 "EHLO us-smtp-delivery-194.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751084AbcGNXQJ convert rfc822-to-8bit (ORCPT ); Thu, 14 Jul 2016 19:16:09 -0400 From: Trond Myklebust To: List Linux Subject: Re: [PATCH 1/4] pNFS: Fix post-layoutget error handling in pnfs_update_layout() Date: Thu, 14 Jul 2016 23:15:50 +0000 Message-ID: <69402880-98F0-4B0D-A0FC-877B803D974B@primarydata.com> References: <1468537115-65826-1-git-send-email-trond.myklebust@primarydata.com> In-Reply-To: <1468537115-65826-1-git-send-email-trond.myklebust@primarydata.com> MIME-Version: 1.0 Content-Type: text/plain; charset=WINDOWS-1252 Sender: linux-nfs-owner@vger.kernel.org List-ID: > On Jul 14, 2016, at 18:58, Trond Myklebust wrote: > > The non-retry error path is currently broken and ends up releasing the > reference to the layout twice. It also can end up clearing the > NFS_LAYOUT_FIRST_LAYOUTGET flag twice, causing a race. > > In addition, the retry path will fail to decrement the plh_outstanding > counter. > > Fixes: 183d9e7b112aa ("pnfs: rework LAYOUTGET retry handling") > Cc: stable@vger.kernel.org # 4.7 > Signed-off-by: Trond Myklebust > --- > fs/nfs/pnfs.c | 20 ++++++++++---------- > 1 file changed, 10 insertions(+), 10 deletions(-) > > diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c > index 0fbe734cc38c..73b0dc90265a 100644 > --- a/fs/nfs/pnfs.c > +++ b/fs/nfs/pnfs.c > @@ -1645,6 +1645,7 @@ lookup_again: > lseg = send_layoutget(lo, ctx, &stateid, &arg, &timeout, gfp_flags); > trace_pnfs_update_layout(ino, pos, count, iomode, lo, lseg, > PNFS_UPDATE_LAYOUT_SEND_LAYOUTGET); > + atomic_dec(&lo->plh_outstanding); > if (IS_ERR(lseg)) { > switch(PTR_ERR(lseg)) { > case -ERECALLCONFLICT: > @@ -1652,26 +1653,25 @@ lookup_again: > lseg = NULL; > /* Fallthrough */ > case -EAGAIN: > - pnfs_put_layout_hdr(lo); > - if (first) > - pnfs_clear_first_layoutget(lo); > - if (lseg) { > - trace_pnfs_update_layout(ino, pos, count, > - iomode, lo, lseg, PNFS_UPDATE_LAYOUT_RETRY); > - goto lookup_again; > - } > - /* Fallthrough */ > + break; > default: > if (!nfs_error_is_fatal(PTR_ERR(lseg))) { > pnfs_layout_clear_fail_bit(lo, pnfs_iomode_to_fail_bit(iomode)); > lseg = NULL; > } > } > + if (lseg) { > + pnfs_put_layout_hdr(lo); Yes, I?m aware I need to move this to after the trace_pnfs_update_layout() below (and before ?goto lookup_again?). I managed to send out an earlier version of the patch that is being committed to linux-next. > + if (first) > + pnfs_clear_first_layoutget(lo); > + trace_pnfs_update_layout(ino, pos, count, > + iomode, lo, lseg, PNFS_UPDATE_LAYOUT_RETRY); > + goto lookup_again; > + } > } else { > pnfs_layout_clear_fail_bit(lo, pnfs_iomode_to_fail_bit(iomode)); > } > > - atomic_dec(&lo->plh_outstanding); > out_put_layout_hdr: > if (first) > pnfs_clear_first_layoutget(lo); > -- > 2.7.4 >