From: Christoph Hellwig <hch@infradead.org>
To: Anna Schumaker <anna@kernel.org>
Cc: linux-nfs@vger.kernel.org, trond.myklebust@hammerspace.com
Subject: Re: [PATCH] NFS: Fix directory delegation verifier checks
Date: Mon, 22 Dec 2025 14:35:10 -0800 [thread overview]
Message-ID: <aUnHnlnDtwMJGP3u@infradead.org> (raw)
In-Reply-To: <20251219201344.380279-1-anna@kernel.org>
On Fri, Dec 19, 2025 at 03:13:44PM -0500, Anna Schumaker wrote:
> From: Anna Schumaker <anna.schumaker@oracle.com>
>
> Doing this check in nfs_check_verifier() resulted in many, many more
> lookups on the wire when running Christoph's delegation benchmarking
> script. After some experimentation, I found that we can treat directory
> delegations exactly the same as having a delegated verifier when we
> reach nfs4_lookup_revalidate() for the best performance.
>
> Reported-by: Christoph Hellwig <hch@lst.de>
> Fixes: 156b09482933 ("NFS: Request a directory delegation on ACCESS, CREATE, and UNLINK")
> Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>
I wish I could actually review this, but I don't actually understand
the lookup revalidation logic enough for that. But it does fix the
problem I saw, so at least:
Tested-by: Christoph Hellwig <hch@lst.de>
next prev parent reply other threads:[~2025-12-22 22:35 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-12-19 20:13 [PATCH] NFS: Fix directory delegation verifier checks Anna Schumaker
2025-12-22 22:35 ` Christoph Hellwig [this message]
2025-12-23 1:06 ` Christoph Hellwig
2025-12-31 21:52 ` Trond Myklebust
2026-01-06 6:21 ` hch@infradead.ori
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