linux-ext4 - Re: [PATCH 3/4] RFC: Remove check for a 32-bit cookie in nfsd4

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Date:	Tue, 9 Aug 2011 14:05:09 -0400
From:	"J. Bruce Fields" <bfields@...ldses.org>
To:	Boaz Harrosh <bharrosh@...asas.com>
Cc:	Bernd Schubert <bernd.schubert@...m.fraunhofer.de>,
	linux-nfs@...r.kernel.org, linux-ext4@...r.kernel.org,
	hch@...radead.org, yong.fan@...mcloud.com,
	linux-fsdevel@...r.kernel.org, tytso@....edu, adilger@...mcloud.com
Subject: Re: [PATCH 3/4] RFC: Remove check for a 32-bit cookie in
 nfsd4_readdir()

On Tue, Aug 09, 2011 at 10:39:04AM -0700, Boaz Harrosh wrote:
> On 08/09/2011 10:31 AM, J. Bruce Fields wrote:
> > On Mon, Aug 08, 2011 at 05:38:08PM +0200, Bernd Schubert wrote:
> >> Fan Yong <yong.fan@...mcloud.com> noticed setting
> >> FMODE_32bithash wouldn't work with nfsd v4, as
> >> nfsd4_readdir() checks for 32 bit cookies. However, according to RFC 3530
> >> cookies have a 64 bit type and cookies are also defined as u64 in
> >> 'struct nfsd4_readdir'. So remove the test for >32-bit values.
> > 
> > Wow, thanks, I wonder where that check came from.  Looks like it was
> > there since the very first nfsv4 commit.
> > 
> 
> Even for the "very first nfsv4 commit" it sounds like a stupid bug.
> Probably a copy/paste from V2 code. What about V3, does V3 code have
> this bug?

I didn't read it carefully, but on a quick skim I don't see any similar
checks.

Not only that, but I don't see them in any historical versions either.

So somebody went out of their way to do that check.  Hm.

--b.

> 
> Boaz
> 
> > Applying.
> > 
> > --b.
> > 
> >>
> >> Signed-off-by: Bernd Schubert <bernd.schubert@...m.fraunhofer.de>
> >> ---
> >>  fs/nfsd/nfs4proc.c |    2 +-
> >>  1 files changed, 1 insertions(+), 1 deletions(-)
> >>
> >> diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
> >> index e807776..9bf0a66 100644
> >> --- a/fs/nfsd/nfs4proc.c
> >> +++ b/fs/nfsd/nfs4proc.c
> >> @@ -691,7 +691,7 @@ nfsd4_readdir(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
> >>  	readdir->rd_bmval[1] &= nfsd_suppattrs1(cstate->minorversion);
> >>  	readdir->rd_bmval[2] &= nfsd_suppattrs2(cstate->minorversion);
> >>  
> >> -	if ((cookie > ~(u32)0) || (cookie == 1) || (cookie == 2) ||
> >> +	if ((cookie == 1) || (cookie == 2) ||
> >>  	    (cookie == 0 && memcmp(readdir->rd_verf.data, zeroverf.data, NFS4_VERIFIER_SIZE)))
> >>  		return nfserr_bad_cookie;
> >>  
> >>
> >> --
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> 
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