From: Christoph Hellwig <hch@lst.de>
To: Chuck Lever <chuck.lever@oracle.com>
Cc: Dai Ngo <dai.ngo@oracle.com>,
Benjamin Coddington <bcodding@hammerspace.com>,
jlayton@kernel.org, neilb@ownmail.net, okorniev@redhat.com,
tom@talpey.com, hch@lst.de, alex.aring@gmail.com,
viro@zeniv.linux.org.uk, brauner@kernel.org, jack@suse.cz,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-nfs@vger.kernel.org
Subject: Re: [Patch 0/2] NFSD: Fix server hang when there are multiple layout conflicts
Date: Tue, 11 Nov 2025 16:36:39 +0100 [thread overview]
Message-ID: <20251111153639.GA9887@lst.de> (raw)
In-Reply-To: <5f014677-42c4-4638-a2ef-a1f285977ff4@oracle.com>
On Tue, Nov 11, 2025 at 10:34:04AM -0500, Chuck Lever wrote:
> > This would help, and I prefer this route rather than rework __break_lease
> > to return EAGAIN/jukebox while the server recalling the layout.
>
> Jeff is looking at continuing Neil's work in this area.
>
> Adding more threads, IMHO, is not a good long term solution for this
> particular issue. There's no guarantee that the server won't get stuck
> no matter how many threads are created, and practically speaking, there
> are only so many threads that can be created before the server goes
> belly up. Or put another way, there's no way to formally prove that the
> server will always be able to make forward progress with this solution.
Agreed.
> We want NFSD to have a generic mechanism for deferring work so that an
> nfsd thread never waits more than a few dozen milliseconds for anything.
> This is the tactic NFSD uses for delegation recalls, for example.
Agreed. This would also be for I/O itself, as with O_DIRECT we can
fully support direct I/O, and even with buffered I/O there is some
limited non-blocking read and write support.
next prev parent reply other threads:[~2025-11-11 15:36 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-06 17:05 [Patch 0/2] NFSD: Fix server hang when there are multiple layout conflicts Dai Ngo
2025-11-06 17:05 ` [PATCH 1/2] locks: Introduce lm_breaker_timedout op to lease_manager_operations Dai Ngo
2025-11-07 13:26 ` Christoph Hellwig
2025-11-07 16:58 ` Dai Ngo
2025-11-06 17:05 ` [PATCH 2/2] NFSD: Fix server hang when there are multiple layout conflicts Dai Ngo
2025-11-07 13:29 ` Christoph Hellwig
2025-11-07 17:01 ` Dai Ngo
2025-11-07 13:30 ` [Patch 0/2] " Christoph Hellwig
2025-11-09 18:34 ` Benjamin Coddington
2025-11-11 15:24 ` Dai Ngo
2025-11-11 15:34 ` Chuck Lever
2025-11-11 15:36 ` Christoph Hellwig [this message]
2025-11-11 15:43 ` Dai Ngo
2025-11-11 15:53 ` Chuck Lever
2025-11-11 15:45 ` Jeff Layton
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