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Date:   Wed, 28 Aug 2019 17:06:15 -0400
From:   "bfields@fieldses.org" <bfields@fieldses.org>
To:     Trond Myklebust <trondmy@hammerspace.com>
Cc:     "aglo@umich.edu" <aglo@umich.edu>,
        "linux-nfs@vger.kernel.org" <linux-nfs@vger.kernel.org>,
        "louis.devandiere@atos.net" <louis.devandiere@atos.net>
Subject: Re: Maximum Number of ACL on NFSv4
Message-ID: <20190828210615.GA32010@fieldses.org>
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On Wed, Aug 28, 2019 at 08:25:16PM +0000, Trond Myklebust wrote:
> Umm... Don't forget that NFSv4 ACL aces are typically much larger than
> POSIX ACL aces because the user/group names are encoded as strings, not
> binary uids and gids.
> 
> IOW: The size of the RPC message is likely to be a lot larger than the
> resulting POSIX ACL...

Actually this limit is post-idmapping, but, yes, before NFSv4->Posix
mapping (complicated in itself), which is why I talked about having to
estimate.

More interested to hear what you think about whether we need a limit at
all.  Do we have any ideas how big is too big a number to pass to
kmalloc?  Or is it OK to just let anything through and let kmalloc fail?

--b.