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Date: Wed, 21 Jan 2026 09:38:07 +0100
From: Christoph Hellwig <hch@lst.de>
To: Dai Ngo <dai.ngo@oracle.com>
Cc: Christoph Hellwig <hch@lst.de>, chuck.lever@oracle.com,
	jlayton@kernel.org, neil@brown.name, okorniev@redhat.com,
	tom@talpey.com, alex.aring@gmail.com, linux-fsdevel@vger.kernel.org,
	linux-nfs@vger.kernel.org
Subject: Re: [PATCH 1/1] NFSD: Enforce recall timeout for layout conflict
Message-ID: <20260121083807.GA15669@lst.de>
References: <20260119174737.3619599-1-dai.ngo@oracle.com> <20260120072638.GA6380@lst.de> <0b0112f8-793c-42af-a2a7-ee662496a9e4@oracle.com>
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On Tue, Jan 20, 2026 at 10:54:39AM -0800, Dai Ngo wrote:
> Thank you Christoph! I have a couple of questions regarding to
> xfs_break_layouts and xfs_break_leased_layouts.
>
> . Should we break out of the while loop in xfs_break_leased_layouts
> if the 2nd call to break_layout, inside the while loop, returns error
> other than -EWOULDBLOCK?

Good question.

> . In xfs_break_leased_layouts, the return value of the 2nd call to
> break_layout was rightly ignored since the call was made without
> holding the xfs_inode lock so there could be a race condition where
> a new layout was handled out to another client.

I have to admin that I'm not sure what other errors we could
have.  Looking through the code I see:

 o -EINVAL for incorrect flags.
 o the error from lease_alloc, which could be -ENOMEM, -EINVAL
   again for a wrong type
 o -EINTR or similar from wait_event_interruptible_timeout

The -EINVAL cases can't happen, for code hygiene they probably should be
handled.  -EINTR means the caller gave up, so it should be handled.
-ENOMEM for the tiny structure is basically impossible to hit, but there
is no point in not giving up, so it should be handled as well.

So yeah, I think we should break out of the loop on error.