linux-kernel - Re: [RFC v3 36/45] NFSv4: Fix GETATTR bitmap verification

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Date:	Thu, 28 May 2015 18:24:28 -0400
From:	Trond Myklebust <trond.myklebust@...marydata.com>
To:	Andreas Grünbacher <andreas.gruenbacher@...il.com>
Cc:	"J. Bruce Fields" <bfields@...ldses.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Linux FS-devel Mailing List <linux-fsdevel@...r.kernel.org>,
	Linux NFS Mailing List <linux-nfs@...r.kernel.org>
Subject: Re: [RFC v3 36/45] NFSv4: Fix GETATTR bitmap verification

On Thu, May 28, 2015 at 6:09 PM, Andreas Grünbacher
<andreas.gruenbacher@...il.com> wrote:
> 2015-05-28 23:55 GMT+02:00 Trond Myklebust <trond.myklebust@...marydata.com>:
>>> We already do this kind of check with the existing code. What's wrong with it?
>>
>> Actually, you're right, we don't check for the previous word, however
>> fixing that is a question of adding 2 extra checks in
>> decode_getfattr_attrs(), one in decode_getfattr_statfs(), and one in
>> decode_fsinfo().
>>
>> It shouldn't require a rewrite of the entire nfs4xdr.c.
>
> I would actually prefer either verifying the reply bitmap against the
> request bitmap,
> or checking the bitmap first as this patch does --- the current
> approach of knocking
> individual bits over and checking if any "before" bits have been missed isn't
> exactly what I would take as a textbook example.


...and I'd prefer that we don't keep rewriting code that works. Screw
the textbooks...

Trond
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