Re: [PATCH v4 01/10] scsi: scsi_debug: Refuse a zoned device with a non-zero lowest aligned LBA

[Damien Le Moal <dlemoal@kernel.org>]

On 2026/09/18 13:29, Niklas Cassel wrote:
> The LOWEST ALIGNED LOGICAL BLOCK ADDRESS field indicates the LBA of the
> first logical block that is located at the beginning of a physical
> block, see SBC-6 r02 (T10/BSR INCITS 587), 5.20.2. scsi_debug reports
> the lowest_aligned module parameter in that field of the READ CAPACITY
> (16) parameter data, but nothing else in the driver acts on it: the data
> it stores begins at LBA 0 and has no physical block structure behind it.
> 
> That does not matter for a device that is not zoned, where a write need
> not end on a physical block boundary at all. It does matter for a zoned
> device: ZBC requires a write to a sequential write required zone to end
> on a physical block boundary, and a zone begins at a multiple of the
> zone size, so a non-zero lowest aligned LBA puts the beginning of every
> zone in the middle of a physical block. A host that writes in units of
> the zone write granularity that it was given can then never satisfy the
> requirement, and such a zone cannot be written at all.
> 
> Refuse the combination rather than emulate a device that cannot be used.
> 
> Assisted-by: LLM
> Signed-off-by: Niklas Cassel <cassel@kernel.org>

Looks good.

Reviewed-by: Damien Le Moal <dlemoal@kernel.org>

-- 
Damien Le Moal
Western Digital Research