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Date: Thu, 23 Apr 2026 07:15:17 +0200
From: Christoph Hellwig <hch@lst.de>
To: Werner Kasselman <werner@verivus.ai>
Cc: Trond Myklebust <trondmy@kernel.org>, Anna Schumaker <anna@kernel.org>,
	Christoph Hellwig <hch@lst.de>,
	"linux-nfs@vger.kernel.org" <linux-nfs@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"stable@vger.kernel.org" <stable@vger.kernel.org>
Subject: Re: [PATCH 1/2] pnfs/blocklayout: validate volume indices and
 limit recursion depth
Message-ID: <20260423051517.GC27929@lst.de>
References: <20260421100338.1227152-1-werner@verivus.com> <20260421100338.1227152-2-werner@verivus.com>
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In-Reply-To: <20260421100338.1227152-2-werner@verivus.com>
User-Agent: Mutt/1.5.17 (2007-11-01)

On Tue, Apr 21, 2026 at 10:03:42AM +0000, Werner Kasselman wrote:
>  #define PNFS_BLOCK_MAX_UUIDS	4
>  #define PNFS_BLOCK_MAX_DEVICES	64
> +#define PNFS_BLOCK_MAX_DEPTH	16

I think we can and should reduce the nesting depth.  The only really
useful nesting is mirroring + striping or concatenation.  Giving a little
extra slack is fine, but I think 4 (or 8 if you insist) should be
enough,

> +		int depth, gfp_t gfp_mask);

unsigned?

>  	default:
> @@ -559,6 +581,9 @@ bl_alloc_deviceid_node(struct nfs_server *server, struct pnfs_device *pdev,
>  		goto out_free_scratch;
>  	nr_volumes = be32_to_cpup(p++);
>  
> +	if (nr_volumes <= 0)
> +		goto out_free_scratch;

nr_volumes should be siwtched to an unsigned value, as it is over
the wire.

Otherwise looks good, thanks a lot!