From: Trond Myklebust <trondmy@hammerspace.com>
To: "bfields@fieldses.org" <bfields@fieldses.org>
Cc: "linux-cachefs@redhat.com" <linux-cachefs@redhat.com>,
"linux-nfs@vger.kernel.org" <linux-nfs@vger.kernel.org>,
"daire@dneg.com" <daire@dneg.com>
Subject: Re: Adventures in NFS re-exporting
Date: Thu, 3 Dec 2020 21:34:26 +0000 [thread overview]
Message-ID: <9df8556bf825bd0d565f057b115e35c1b507cf46.camel@hammerspace.com> (raw)
In-Reply-To: <20201203211328.GC27931@fieldses.org>
On Thu, 2020-12-03 at 16:13 -0500, bfields@fieldses.org wrote:
> On Thu, Dec 03, 2020 at 08:27:39PM +0000, Trond Myklebust wrote:
> > On Thu, 2020-12-03 at 13:51 -0500, bfields wrote:
> > > I've been scratching my head over how to handle reboot of a re-
> > > exporting
> > > server. I think one way to fix it might be just to allow the re-
> > > export
> > > server to pass along reclaims to the original server as it
> > > receives
> > > them
> > > from its own clients. It might require some protocol tweaks, I'm
> > > not
> > > sure. I'll try to get my thoughts in order and propose
> > > something.
> > >
> >
> > It's more complicated than that. If the re-exporting server
> > reboots,
> > but the original server does not, then unless that re-exporting
> > server
> > persisted its lease and a full set of stateids somewhere, it will
> > not
> > be able to atomically reclaim delegation and lock state on the
> > server
> > on behalf of its clients.
>
> By sending reclaims to the original server, I mean literally sending
> new
> open and lock requests with the RECLAIM bit set, which would get
> brand
> new stateids.
>
> So, the original server would invalidate the existing client's
> previous
> clientid and stateids--just as it normally would on reboot--but it
> would
> optionally remember the underlying locks held by the client and allow
> compatible lock reclaims.
>
> Rough attempt:
>
> https://wiki.linux-nfs.org/wiki/index.php/Reboot_recovery_for_re-export_servers
>
> Think it would fly?
So this would be a variant of courtesy locks that can be reclaimed by
the client using the reboot reclaim variant of OPEN/LOCK outside the
grace period? The purpose being to allow reclaim without forcing the
client to persist the original stateid?
Hmm... That's doable, but how about the following alternative: Add a
function that allows the client to request the full list of stateids
that the server holds on its behalf?
I've been wanting such a function for quite a while anyway in order to
allow the client to detect state leaks (either due to soft timeouts, or
due to reordered close/open operations).
--
Trond Myklebust
Linux NFS client maintainer, Hammerspace
trond.myklebust@hammerspace.com
next prev parent reply other threads:[~2020-12-03 21:35 UTC|newest]
Thread overview: 129+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-07 17:31 Adventures in NFS re-exporting Daire Byrne
2020-09-08 9:40 ` Mkrtchyan, Tigran
2020-09-08 11:06 ` Daire Byrne
2020-09-15 17:21 ` J. Bruce Fields
2020-09-15 19:59 ` Trond Myklebust
2020-09-16 16:01 ` Daire Byrne
2020-10-19 16:19 ` Daire Byrne
2020-10-19 17:53 ` [PATCH 0/2] Add NFSv3 emulation of the lookupp operation trondmy
2020-10-19 17:53 ` [PATCH 1/2] NFSv3: Refactor nfs3_proc_lookup() to split out the dentry trondmy
2020-10-19 17:53 ` [PATCH 2/2] NFSv3: Add emulation of the lookupp() operation trondmy
2020-10-19 20:05 ` [PATCH v2 0/2] Add NFSv3 emulation of the lookupp operation trondmy
2020-10-19 20:05 ` [PATCH v2 1/2] NFSv3: Refactor nfs3_proc_lookup() to split out the dentry trondmy
2020-10-19 20:05 ` [PATCH v2 2/2] NFSv3: Add emulation of the lookupp() operation trondmy
2020-10-20 18:37 ` [PATCH v3 0/3] Add NFSv3 emulation of the lookupp operation trondmy
2020-10-20 18:37 ` [PATCH v3 1/3] NFSv3: Refactor nfs3_proc_lookup() to split out the dentry trondmy
2020-10-20 18:37 ` [PATCH v3 2/3] NFSv3: Add emulation of the lookupp() operation trondmy
2020-10-20 18:37 ` [PATCH v3 3/3] NFSv4: Observe the NFS_MOUNT_SOFTREVAL flag in _nfs4_proc_lookupp trondmy
2020-10-21 9:33 ` Adventures in NFS re-exporting Daire Byrne
2020-11-09 16:02 ` bfields
2020-11-12 13:01 ` Daire Byrne
2020-11-12 13:57 ` bfields
2020-11-12 18:33 ` Daire Byrne
2020-11-12 20:55 ` bfields
2020-11-12 23:05 ` Daire Byrne
2020-11-13 14:50 ` bfields
2020-11-13 22:26 ` bfields
2020-11-14 12:57 ` Daire Byrne
2020-11-16 15:18 ` bfields
2020-11-16 15:53 ` bfields
2020-11-16 19:21 ` Daire Byrne
2020-11-16 15:29 ` Jeff Layton
2020-11-16 15:56 ` bfields
2020-11-16 16:03 ` Jeff Layton
2020-11-16 16:14 ` bfields
2020-11-16 16:38 ` Jeff Layton
2020-11-16 19:03 ` bfields
2020-11-16 20:03 ` Jeff Layton
2020-11-17 3:16 ` bfields
2020-11-17 3:18 ` [PATCH 1/4] nfsd: move fill_{pre,post}_wcc to nfsfh.c J. Bruce Fields
2020-11-17 3:18 ` [PATCH 2/4] nfsd: pre/post attr is using wrong change attribute J. Bruce Fields
2020-11-17 12:34 ` Jeff Layton
2020-11-17 15:26 ` J. Bruce Fields
2020-11-17 15:34 ` Jeff Layton
2020-11-20 22:38 ` J. Bruce Fields
2020-11-20 22:39 ` [PATCH 1/8] nfsd: only call inode_query_iversion in the I_VERSION case J. Bruce Fields
2020-11-20 22:39 ` [PATCH 2/8] nfsd: simplify nfsd4_change_info J. Bruce Fields
2020-11-20 22:39 ` [PATCH 3/8] nfsd: minor nfsd4_change_attribute cleanup J. Bruce Fields
2020-11-21 0:34 ` Jeff Layton
2020-11-20 22:39 ` [PATCH 4/8] nfsd4: don't query change attribute in v2/v3 case J. Bruce Fields
2020-11-20 22:39 ` [PATCH 5/8] nfs: use change attribute for NFS re-exports J. Bruce Fields
2020-11-20 22:39 ` [PATCH 6/8] nfsd: move change attribute generation to filesystem J. Bruce Fields
2020-11-21 0:58 ` Jeff Layton
2020-11-21 1:01 ` J. Bruce Fields
2020-11-21 13:00 ` Jeff Layton
2020-11-20 22:39 ` [PATCH 7/8] nfsd: skip some unnecessary stats in the v4 case J. Bruce Fields
2020-11-20 22:39 ` [PATCH 8/8] Revert "nfsd4: support change_attr_type attribute" J. Bruce Fields
2020-11-20 22:44 ` [PATCH 2/4] nfsd: pre/post attr is using wrong change attribute J. Bruce Fields
2020-11-21 1:03 ` Jeff Layton
2020-11-21 21:44 ` Daire Byrne
2020-11-22 0:02 ` bfields
2020-11-22 1:55 ` Daire Byrne
2020-11-22 3:03 ` bfields
2020-11-23 20:07 ` Daire Byrne
2020-11-17 15:25 ` J. Bruce Fields
2020-11-17 3:18 ` [PATCH 3/4] nfs: don't mangle i_version on NFS J. Bruce Fields
2020-11-17 12:27 ` Jeff Layton
2020-11-17 14:14 ` J. Bruce Fields
2020-11-17 3:18 ` [PATCH 4/4] nfs: support i_version in the NFSv4 case J. Bruce Fields
2020-11-17 12:34 ` Jeff Layton
2020-11-24 20:35 ` Adventures in NFS re-exporting Daire Byrne
2020-11-24 21:15 ` bfields
2020-11-24 22:15 ` Frank Filz
2020-11-25 14:47 ` 'bfields'
2020-11-25 16:25 ` Frank Filz
2020-11-25 19:03 ` 'bfields'
2020-11-26 0:04 ` Frank Filz
2020-11-25 17:14 ` Daire Byrne
2020-11-25 19:31 ` bfields
2020-12-03 12:20 ` Daire Byrne
2020-12-03 18:51 ` bfields
2020-12-03 20:27 ` Trond Myklebust
2020-12-03 21:13 ` bfields
2020-12-03 21:32 ` Frank Filz
2020-12-03 21:34 ` Trond Myklebust [this message]
2020-12-03 21:45 ` Frank Filz
2020-12-03 21:57 ` Trond Myklebust
2020-12-03 22:04 ` bfields
2020-12-03 22:14 ` Trond Myklebust
2020-12-03 22:39 ` Frank Filz
2020-12-03 22:50 ` Trond Myklebust
2020-12-03 23:34 ` Frank Filz
2020-12-03 22:44 ` bfields
2020-12-03 21:54 ` bfields
2020-12-03 22:45 ` bfields
2020-12-03 22:53 ` Trond Myklebust
2020-12-03 23:16 ` bfields
2020-12-03 23:28 ` Frank Filz
2020-12-04 1:02 ` Trond Myklebust
2020-12-04 1:41 ` bfields
2020-12-04 2:27 ` Trond Myklebust
2020-09-17 16:01 ` Daire Byrne
2020-09-17 19:09 ` bfields
2020-09-17 20:23 ` Frank van der Linden
2020-09-17 21:57 ` bfields
2020-09-19 11:08 ` Daire Byrne
2020-09-22 16:43 ` Chuck Lever
2020-09-23 20:25 ` Daire Byrne
2020-09-23 21:01 ` Frank van der Linden
2020-09-26 9:00 ` Daire Byrne
2020-09-28 15:49 ` Frank van der Linden
2020-09-28 16:08 ` Chuck Lever
2020-09-28 17:42 ` Frank van der Linden
2020-09-22 12:31 ` Daire Byrne
2020-09-22 13:52 ` Trond Myklebust
2020-09-23 12:40 ` J. Bruce Fields
2020-09-23 13:09 ` Trond Myklebust
2020-09-23 17:07 ` bfields
2020-09-30 19:30 ` [Linux-cachefs] " Jeff Layton
2020-10-01 0:09 ` Daire Byrne
2020-10-01 10:36 ` Jeff Layton
2020-10-01 12:38 ` Trond Myklebust
2020-10-01 16:39 ` Jeff Layton
2020-10-05 12:54 ` Daire Byrne
2020-10-13 9:59 ` Daire Byrne
2020-10-01 18:41 ` J. Bruce Fields
2020-10-01 19:24 ` Trond Myklebust
2020-10-01 19:26 ` bfields
2020-10-01 19:29 ` Trond Myklebust
2020-10-01 19:51 ` bfields
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