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Date: Wed, 11 Nov 2026 17:47:05 +0100
From: Christoph Hellwig <hch@lst.de>
To: Chris Down <chris@chrisdown.name>
Cc: "Martin K. Petersen" <mkp@kernel.org>,
	"James E.J. Bottomley" <James.Bottomley@hansenpartnership.com>,
	Christoph Hellwig <hch@lst.de>, linux-scsi@vger.kernel.org,
	linux-kernel@vger.kernel.org, kernel-team@meta.com
Subject: Re: [PATCH 2/2] scsi: sd: Fix data corruption in WRITE SAME(10)
 discards
Message-ID: <20261111164705.GC18355@lst.de>
References: <cover.1794069087.git.chris@chrisdown.name> <c58578f870580f92d1acd6cb73b59b7a7867d80b.1794069087.git.chris@chrisdown.name>
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On Sat, Nov 07, 2026 at 08:35:29AM -0800, Chris Down wrote:
> We already cap the discard length in writesame_10 and writesame_zero
> mode, but we still truncate the starting LBA to 32 bits. A discard at
> or above block 2^32 can corrupt live data near the start of the disk
> and still report success.
> 
> Discard is advisory, so return BLK_STS_NOTSUPP if the request won't
> fit in WRITE SAME(10). Discards that fit can still go through.

Nah, that's not really how things work.  See my reply to patch 1
for the suggested proper fix.