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From: Christoph Hellwig <hch@lst.de>
To: Dai Ngo <dai.ngo@oracle.com>
Cc: chuck.lever@oracle.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: Fri, 7 Nov 2025 14:30:45 +0100	[thread overview]
Message-ID: <20251107133045.GA5158@lst.de> (raw)
In-Reply-To: <20251106170729.310683-1-dai.ngo@oracle.com>

On Thu, Nov 06, 2025 at 09:05:24AM -0800, Dai Ngo wrote:
> When a layout conflict triggers a call to __break_lease, the function
> nfsd4_layout_lm_break clears the fl_break_time timeout before sending
> the CB_LAYOUTRECALL. As a result, __break_lease repeatedly restarts
> its loop, waiting indefinitely for the conflicting file lease to be
> released.
> 
> If the number of lease conflicts matches the number of NFSD threads (which
> defaults to 8), all available NFSD threads become occupied. Consequently,
> there are no threads left to handle incoming requests or callback replies,
> leading to a total hang of the NFS server.
> 
> This issue is reliably reproducible by running the Git test suite on a
> configuration using SCSI layout.

I guess we need to implement asynchronous breaking of leases.  Which
conceptually shouldn't be too hard.


  parent reply	other threads:[~2025-11-07 13:30 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 ` Christoph Hellwig [this message]
2025-11-09 18:34 ` [Patch 0/2] " Benjamin Coddington
2025-11-11 15:24   ` Dai Ngo
2025-11-11 15:34     ` Chuck Lever
2025-11-11 15:36       ` Christoph Hellwig
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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