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Date: Thu, 26 Mar 2026 06:33:59 +0100
From: Christoph Hellwig <hch@lst.de>
To: Chuck Lever <cel@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>, Chuck Lever <chuck.lever@oracle.com>,
	Jeff Layton <jlayton@kernel.org>,
	Amir Goldstein <amir73il@gmail.com>, NeilBrown <neil@brown.name>,
	Olga Kornievskaia <okorniev@redhat.com>,
	Dai Ngo <Dai.Ngo@oracle.com>, Tom Talpey <tom@talpey.com>,
	Carlos Maiolino <cem@kernel.org>, linux-nfs@vger.kernel.org,
	linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH 1/7] exportfs: split out the ops for layout-based block
 device access
Message-ID: <20260326053359.GA23157@lst.de>
References: <20260323070746.2940140-1-hch@lst.de> <20260323070746.2940140-2-hch@lst.de> <1fbdc5d9-d95c-4d1a-816e-028ffd1231b0@app.fastmail.com>
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On Mon, Mar 23, 2026 at 09:39:48AM -0400, Chuck Lever wrote:
> > -	    sb->s_export_op->commit_blocks &&
> > +	if (bops->map_blocks && bops->commit_blocks &&
> >  	    sb->s_bdev &&
> >  	    sb->s_bdev->bd_disk->fops->pr_ops &&
> >  	    sb->s_bdev->bd_disk->fops->get_unique_id)
> 
> block_ops itself is NULL for any filesystem that does not provide
> block layout support (everything other than XFS today).
> 
> When an admin exports such a filesystem with pNFS enabled
> (NFSEXP_PNFS), svc_export_parse() calls nfsd4_setup_layout_type(),
> and bops->get_uuid dereferences a NULL pointer.
> 
> Something like the following would restore the original behavior:
> 
>     if (bops && bops->get_uuid && ...)

Yes, I'll fix it up.