Re: [PATCH 6/7] scsi: sd_zbc: always revalidate zones for disks supporting head depopulation

[Hannes Reinecke <hare@suse.de>]

On 10/5/26 11:46 AM, Damien Le Moal wrote:
> sd_zbc_revalidate_zones() skips revalidating the zones of a ZBC device if
> the zone size and total number of zones of the disk has not changed. This
> is to avoid a call to the rather slow blk_revalidate_disk_zones().
> 
> However, for ZBC devices that support data preserving head depopulation
> (REMOVE ELEMENT AND MODIFY ZONES command), a disk capacity and number of
> zones does not change after a head is depopulated but the condition of
> zones changes as the zones served by the head that was depopulated become
> either read-only or offline. In this case, not calling
> blk_revalidate_disk_zones() prevents the block layer from taking
> appropriate actions on the zone write plugs of the disk for the zones that
> became read-only or offline.
> 
> Avoid any issue with the block layer view of the zone conditions by not
> skipping the call to blk_revalidate_disk_zones() for disks that support
> the REMOVE ELEMENT AND MODIFY ZONES command. This check is done from
> sd_zbc_read_zones() using the helper function sd_zbc_check_modify_zones().
> The new scsi disk flag modify_zones_supported is defined to remember the
> result of this check.
> 
> Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
> ---
>   drivers/scsi/sd.h     |  1 +
>   drivers/scsi/sd_zbc.c | 26 +++++++++++++++++++++++++-
>   2 files changed, 26 insertions(+), 1 deletion(-)
> 
Reviewed-by: Hannes Reinecke <hare@kernel.org>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                  Kernel Storage Architect
hare@suse.de                                +49 911 74053 688
SUSE Software Solutions GmbH, Frankenstr. 146, 90461 Nürnberg
HRB 36809 (AG Nürnberg), GF: I. Totev, A. McDonald, W. Knoblich