From: "J. Bruce Fields" <bfields@redhat.com>
To: Olga Kornievskaia <olga.kornievskaia@gmail.com>
Cc: "J. Bruce Fields" <bfields@fieldses.org>,
linux-nfs <linux-nfs@vger.kernel.org>
Subject: Re: [PATCH v4 5/8] NFSD check stateids against copy stateids
Date: Wed, 31 Jul 2019 17:51:18 -0400 [thread overview]
Message-ID: <20190731215118.GA13311@parsley.fieldses.org> (raw)
In-Reply-To: <CAN-5tyEbwjPNbXKWXv+3=geisjH-i=xKWRqgyXa3v9Xk=OvdEw@mail.gmail.com>
On Wed, Jul 31, 2019 at 05:10:01PM -0400, Olga Kornievskaia wrote:
> I'm having difficulty with this patch because there is no good way to
> know when the copy_notify stateid can be freed. What I can propose is
> to have the linux client send a FREE_STATEID with the copy_notify
> stateid and use that as the trigger to free the state. In that case,
> I'll keep a reference on the parent until the FREE_STATEID is
> received.
>
> This is not in the spec (though seems like a good idea to tell the
> source server it's ok to clean up) so other implementations might not
> choose this approach so we'll have problems with stateids sticking
> around.
https://tools.ietf.org/html/rfc7862#page-71
"If the cnr_lease_time expires while the destination server is
still reading the source file, the destination server is allowed
to finish reading the file. If the cnr_lease_time expires
before the destination server uses READ or READ_PLUS to begin
the transfer, the source server can use NFS4ERR_PARTNER_NO_AUTH
to inform the destination server that the cnr_lease_time has
expired."
The spec doesn't really define what "is allowed to finish reading the
file" means, but I think the source server should decide somehow whether
the target's done. And "hasn't sent a read in cnr_lease_time" seems
like a pretty good conservative definition that would be easy to
enforce. Worst case, if the network goes down for a couple minutes and
the target tries to pick up a copy where it left off, it'll get
PARTNER_NO_AUTH. I assume that results in the same error being returned
the client, at which point the client knows that the copy_notify stateid
may have installed and can do what it chooses to recover (like send a
new copy_notify).
The FREE_STATEID might also be a good idea, but I guess we can't count
on it.
Maybe the spec could use some errata to clarify that FREE_STATEID is
allowed on copy_notify stateids, that clients should send it when
they're done, and that servers are allowed to expire copy_notify
stateid's even after their first use.
--b.
next prev parent reply other threads:[~2019-07-31 21:51 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-08 19:23 [PATCH v4 0/8] server-side support for "inter" SSC copy Olga Kornievskaia
2019-07-08 19:23 ` [PATCH v4 1/8] NFSD fill-in netloc4 structure Olga Kornievskaia
2019-07-17 21:13 ` J. Bruce Fields
2019-07-22 19:59 ` Olga Kornievskaia
2019-07-30 15:48 ` Olga Kornievskaia
2019-07-30 15:51 ` J. Bruce Fields
2019-07-08 19:23 ` [PATCH v4 2/8] NFSD add ca_source_server<> to COPY Olga Kornievskaia
2019-07-17 21:40 ` J. Bruce Fields
2019-07-22 20:00 ` Olga Kornievskaia
2019-07-08 19:23 ` [PATCH v4 3/8] NFSD return nfs4_stid in nfs4_preprocess_stateid_op Olga Kornievskaia
2019-07-08 19:23 ` [PATCH v4 4/8] NFSD add COPY_NOTIFY operation Olga Kornievskaia
2019-07-09 12:34 ` Anna Schumaker
2019-07-09 15:51 ` Olga Kornievskaia
2019-07-17 22:12 ` J. Bruce Fields
2019-07-17 22:15 ` J. Bruce Fields
2019-07-22 20:03 ` Olga Kornievskaia
2019-07-17 23:07 ` J. Bruce Fields
2019-07-22 20:17 ` Olga Kornievskaia
2019-07-23 20:45 ` J. Bruce Fields
2019-07-30 15:48 ` Olga Kornievskaia
2019-07-30 15:55 ` J. Bruce Fields
2019-07-30 16:13 ` Olga Kornievskaia
2019-07-30 17:10 ` Olga Kornievskaia
2019-07-08 19:23 ` [PATCH v4 5/8] NFSD check stateids against copy stateids Olga Kornievskaia
2019-07-19 22:01 ` J. Bruce Fields
2019-07-22 20:24 ` Olga Kornievskaia
2019-07-23 20:58 ` J. Bruce Fields
2019-07-30 16:03 ` Olga Kornievskaia
2019-07-31 21:10 ` Olga Kornievskaia
2019-07-31 21:51 ` J. Bruce Fields [this message]
2019-08-01 14:12 ` Olga Kornievskaia
2019-08-01 15:12 ` J. Bruce Fields
2019-08-01 15:41 ` Olga Kornievskaia
2019-08-01 18:06 ` Olga Kornievskaia
2019-08-01 18:11 ` J. Bruce Fields
2019-08-01 18:24 ` Olga Kornievskaia
2019-08-01 19:36 ` J. Bruce Fields
2019-08-07 16:02 ` Olga Kornievskaia
2019-08-07 16:08 ` J. Bruce Fields
2019-08-07 16:42 ` Olga Kornievskaia
2019-08-08 11:25 ` J. Bruce Fields
2019-07-08 19:23 ` [PATCH v4 6/8] NFSD generalize nfsd4_compound_state flag names Olga Kornievskaia
2019-07-08 19:23 ` [PATCH v4 7/8] NFSD: allow inter server COPY to have a STALE source server fh Olga Kornievskaia
2019-07-23 21:35 ` J. Bruce Fields
2019-07-30 15:48 ` Olga Kornievskaia
2019-07-08 19:23 ` [PATCH v4 8/8] NFSD add nfs4 inter ssc to nfsd4_copy Olga Kornievskaia
2019-07-09 12:43 ` Anna Schumaker
2019-07-09 15:53 ` Olga Kornievskaia
2019-07-09 3:53 ` [PATCH v4 0/8] server-side support for "inter" SSC copy J. Bruce Fields
2019-07-09 15:47 ` Olga Kornievskaia
2019-07-17 18:05 ` Olga Kornievskaia
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