From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-17.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 39217C2B9F4 for ; Mon, 14 Jun 2021 19:34:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 12A0261246 for ; Mon, 14 Jun 2021 19:34:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234729AbhFNTgO (ORCPT ); Mon, 14 Jun 2021 15:36:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38768 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234476AbhFNTgN (ORCPT ); Mon, 14 Jun 2021 15:36:13 -0400 Received: from fieldses.org (fieldses.org [IPv6:2600:3c00:e000:2f7::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BA2BBC061574 for ; Mon, 14 Jun 2021 12:34:10 -0700 (PDT) Received: by fieldses.org (Postfix, from userid 2815) id CB1FB6210; Mon, 14 Jun 2021 15:34:09 -0400 (EDT) DKIM-Filter: OpenDKIM Filter v2.11.0 fieldses.org CB1FB6210 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fieldses.org; s=default; t=1623699249; bh=No9VxRYI9052kbIk228uZZ117l660NzZsKZ7GmuRCFc=; h=Date:To:Cc:Subject:References:In-Reply-To:From:From; b=i2YoLaTmQlzbuil1+xEre2LgiG5S5fEdY7sGDUmEtDqCE2Pl6zrplHwHRgv2F51u7 sITpQnaK4Hybv/5Z2Fn8Y7W5z6jckG4AW0rX4BihvrLSBMfTKol6KcyITfT6OXhgIf ZcslyoEzCOtORNrL12TK9aYNcOJoidiKlGn9SGRw= Date: Mon, 14 Jun 2021 15:34:09 -0400 To: Trond Myklebust Cc: "schumakeranna@gmail.com" , "bfields@redhat.com" , "linux-nfs@vger.kernel.org" , "daire@dneg.com" Subject: Re: [PATCH 3/3] nfs: don't allow reexport reclaims Message-ID: <20210614193409.GA16500@fieldses.org> References: <1623682098-13236-1-git-send-email-bfields@redhat.com> <1623682098-13236-4-git-send-email-bfields@redhat.com> <3189d061c1e862fe305e501226fcc9ebc1fe544d.camel@hammerspace.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <3189d061c1e862fe305e501226fcc9ebc1fe544d.camel@hammerspace.com> User-Agent: Mutt/1.5.21 (2010-09-15) From: bfields@fieldses.org (J. Bruce Fields) Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org On Mon, Jun 14, 2021 at 02:56:55PM +0000, Trond Myklebust wrote: > On Mon, 2021-06-14 at 10:48 -0400, J. Bruce Fields wrote: > > From: "J. Bruce Fields" > > > > In the reexport case, nfsd is currently passing along locks with the > > reclaim bit set.  The client sends a new lock request, which is > > granted > > if there's currently no conflict--even if it's possible a conflicting > > lock could have been briefly held in the interim. > > > > We don't currently have any way to safely grant reclaim, so for now > > let's just deny them all. > > > > I'm doing this by passing the reclaim bit to nfs and letting it fail > > the > > call, with the idea that eventually the client might be able to do > > something more forgiving here. > > > > Signed-off-by: J. Bruce Fields > > --- > >  fs/nfs/file.c       | 3 +++ > >  fs/nfsd/nfs4state.c | 3 +++ > >  fs/nfsd/nfsproc.c   | 1 + > >  include/linux/fs.h  | 1 + > >  4 files changed, 8 insertions(+) > > > > diff --git a/fs/nfs/file.c b/fs/nfs/file.c > > index 1fef107961bc..35a29b440e3e 100644 > > --- a/fs/nfs/file.c > > +++ b/fs/nfs/file.c > > @@ -806,6 +806,9 @@ int nfs_lock(struct file *filp, int cmd, struct > > file_lock *fl) > >   > >         nfs_inc_stats(inode, NFSIOS_VFSLOCK); > >   > > +       if (fl->fl_flags & FL_RECLAIM) > > +               return -NFSERR_NO_GRACE; > > NACK. nfs_lock() is required to return a POSIX error. I know that right > now, nfsd is the only thing setting FL_RECLAIM, but we can't guarantee > that will always be the case. Setting FL_RECLAIM tells the filesystem that you're prepared to handle NFSERR_NO_GRACE. I'm not seeing the risk. --b. > >         /* No mandatory locks over NFS */ > >         if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK) > >                 goto out_err; > > diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c > > index 00d98bbab2a6..3ef42c0d5d38 100644 > > --- a/fs/nfsd/nfs4state.c > > +++ b/fs/nfsd/nfs4state.c > > @@ -6903,6 +6903,9 @@ nfsd4_lock(struct svc_rqst *rqstp, struct > > nfsd4_compound_state *cstate, > >         if (!locks_in_grace(net) && lock->lk_reclaim) > >                 goto out; > >   > > +       if (lock->lk_reclaim) > > +               fl_flags |= FL_RECLAIM; > > + > >         fp = lock_stp->st_stid.sc_file; > >         switch (lock->lk_type) { > >                 case NFS4_READW_LT: > > diff --git a/fs/nfsd/nfsproc.c b/fs/nfsd/nfsproc.c > > index 60d7c59e7935..80c430c37ab7 100644 > > --- a/fs/nfsd/nfsproc.c > > +++ b/fs/nfsd/nfsproc.c > > @@ -881,6 +881,7 @@ nfserrno (int errno) > >                 { nfserr_serverfault, -ENFILE }, > >                 { nfserr_io, -EUCLEAN }, > >                 { nfserr_perm, -ENOKEY }, > > +               { nfserr_no_grace, -NFSERR_NO_GRACE}, > >         }; > >         int     i; > >   > > diff --git a/include/linux/fs.h b/include/linux/fs.h > > index c3c88fdb9b2a..9be479999109 100644 > > --- a/include/linux/fs.h > > +++ b/include/linux/fs.h > > @@ -997,6 +997,7 @@ static inline struct file *get_file(struct file > > *f) > >  #define FL_UNLOCK_PENDING      512 /* Lease is being broken */ > >  #define FL_OFDLCK      1024    /* lock is "owned" by struct file */ > >  #define FL_LAYOUT      2048    /* outstanding pNFS layout */ > > +#define FL_RECLAIM     4096    /* reclaiming from a reboot server */ > >   > >  #define FL_CLOSE_POSIX (FL_POSIX | FL_CLOSE) > >   > > -- > Trond Myklebust > Linux NFS client maintainer, Hammerspace > trond.myklebust@hammerspace.com > >