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Date: Wed, 19 Nov 2025 10:00:10 +0100
From: Christoph Hellwig <hch@lst.de>
To: Uladzislau Rezki <urezki@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>, Mikulas Patocka <mpatocka@redhat.com>,
	Benjamin Marzinski <bmarzins@redhat.com>,
	Alasdair Kergon <agk@redhat.com>, DMML <dm-devel@lists.linux.dev>,
	Andrew Morton <akpm@linux-foundation.org>,
	Mike Snitzer <snitzer@redhat.com>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [RESEND PATCH] dm-ebs: Mark full buffer dirty even on partial
 write
Message-ID: <20251119090010.GA24598@lst.de>
References: <20251117105945.10179-1-urezki@gmail.com> <fff990bc-6ff9-7b34-8e80-57078de40928@redhat.com> <aRxa1wPMsJwBubjx@pc636> <73556fc8-5fbf-37cb-26b9-7cdb88f69720@redhat.com> <aRx_lCimJco5BPKA@redhat.com> <230baa83-cd79-f232-5fb8-1476115e1ae7@redhat.com> <20251119054635.GB19993@lst.de> <aR2DIXsymZWD9EvG@pc636> <20251119085328.GA24461@lst.de> <aR2GjRaNWrfHbDGQ@pc636>
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User-Agent: Mutt/1.5.17 (2007-11-01)

On Wed, Nov 19, 2025 at 09:57:49AM +0100, Uladzislau Rezki wrote:
> On Wed, Nov 19, 2025 at 09:53:28AM +0100, Christoph Hellwig wrote:
> > On Wed, Nov 19, 2025 at 09:43:13AM +0100, Uladzislau Rezki wrote:
> > > Well. LBA is fixed in my case. Just only one format which is 512B.
> > > 
> > > Whereas the I/O can not be performed by using LBAs sizes. It is fixed
> > > and bigger.
> > 
> > Then it is not an LBA.  The LBA is defined as the minimum block size
> > you can do I/O on.  Aka your device is really gravely broken.  What
> > device is this and who is selling it?
> > 
> I define UBS - underlying block size. The lower layer expects BIOs in
> that sizes but this is not true.
> 
> I am not allowed to disclose and answer your last question.

Well.  Let's frame it differently:  this device is just to broken
to be used with Linux.  In theory we could quirk based on the vendor
ID to correctly report the logical block size, but for that we'd
need the information.