From: bfields <bfields@fieldses.org>
To: Richard Weinberger <richard@nod.at>
Cc: linux-nfs <linux-nfs@vger.kernel.org>,
luis turcitu <luis.turcitu@appsbroker.com>,
chris chilvers <chris.chilvers@appsbroker.com>,
david young <david.young@appsbroker.com>,
Daire Byrne <daire@dneg.com>,
david oberhollenzer <david.oberhollenzer@sigma-star.at>,
david <david@sigma-star.at>,
goliath@sigma-star.at,
trond myklebust <trond.myklebust@hammerspace.com>,
anna schumaker <anna.schumaker@netapp.com>
Subject: Re: [RFC PATCH] mountd: export: Deal with NFS filesystems
Date: Mon, 31 Jan 2022 15:37:42 -0500 [thread overview]
Message-ID: <20220131203742.GE30119@fieldses.org> (raw)
In-Reply-To: <8290532.5517.1643649341941.JavaMail.zimbra@nod.at>
On Mon, Jan 31, 2022 at 06:15:41PM +0100, Richard Weinberger wrote:
> ----- Ursprüngliche Mail -----
> > Von: "bfields" <bfields@fieldses.org>
> >> Using /proc/fs/nfsfs/volumes it is possible to find the NFS fsid
> >> from the backend and use it as seed for mountd's UUID mechanism.
> >
> > Sorry, I haven't checked--what is that number, really? It's probably
> > not the fsid returned from the server, as that wouldn't be guaranteed
> > unique across multiple servers. But that means it's probably generated
> > in a way that doesn't guarantee it's stable across reboots. And we need
> > filehandles to work across reboots.
>
> Unless I badly misunderstood the code it comes from fs/nfs/client.c's
> nfs_create_server() where the NFS client fetches NFS_ATTR_FATTR via getattr().
> So it should be unique:
> https://datatracker.ietf.org/doc/html/rfc7530#section-5.8.1.9
Unique within one server, but not across different servers.
Depending on how your servers assign fsids, collisions might be quite
likely. Results of a collision would be pretty bad.
--b.
next prev parent reply other threads:[~2022-01-31 20:37 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-31 10:43 [RFC PATCH] mountd: export: Deal with NFS filesystems Richard Weinberger
2022-01-31 17:01 ` J. Bruce Fields
2022-01-31 17:15 ` Richard Weinberger
2022-01-31 20:37 ` bfields [this message]
2022-01-31 21:57 ` Richard Weinberger
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