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From:   "Benjamin Coddington" <bcodding@redhat.com>
To:     "Trond Myklebust" <trondmy@hammerspace.com>
Cc:     linux-nfs@vger.kernel.org
Subject: Re: [PATCH v6 05/13] NFS: Improve algorithm for falling back to
 uncached readdir
Date:   Mon, 21 Feb 2022 16:10:29 -0500
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On 21 Feb 2022, at 15:55, Trond Myklebust wrote:
>
> We will always need the ability to cut over to uncached readdir.

Yes.

> If the cookie is no longer returned by the server because one or more
> files were deleted then we need to resolve the situation somehow (IOW:
> the 'rm *' case). The new algorithm _does_ improve performance on those
> situations, because it no longer requires us to read the entire
> directory before switching over: we try 5 times, then fail over.

Yes, using per-page validation doesn't remove the need for uncached readdir.
It does allow a reader to simply resume filling the cache where it left
off.  There's no need to try 5 times and fail over.  And there's no need to
make a trade-off and make the situation worse in certain scenarios.

I thought I'd point that out and make an offer to re-submit it.  Any
interest?

Ben