Re: [PATCH v3 5/6] scsi: scsi_debug: Map the region written by WRITE ATOMIC (16)

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

On 2026/09/17 19:54, Niklas Cassel wrote:
> When logical block provisioning is enabled, a command that writes user
> data marks the region that it wrote in the provisioning map, so that
> GET LBA STATUS reports the region as mapped. resp_write_dt0(),
> resp_write_scat() and resp_write_same() all call map_region() for that.
> 
> resp_atomic_write() does not, so a WRITE ATOMIC (16) leaves the
> provisioning map untouched, and GET LBA STATUS keeps reporting the
> region as deallocated after it has been written. map_state(), which
> GET LBA STATUS uses, is the only reader of the map, so that is the whole
> of the effect.
> 
> Call map_region() the way resp_write_dt0() does, and take the zone
> metadata write lock across the access as it does when logical block
> provisioning is enabled. That lock is what serialises the provisioning
> map against resp_unmap(), which holds it while unmap_region() clears map
> bits and zeroes the data that they cover. resp_unmap() does nothing
> unless logical block provisioning is enabled, so the lock is only needed
> in that case.
> 
> Assisted-by: LLM
> Fixes: 84f3a3c01d70 ("scsi: scsi_debug: Atomic write support")
> Signed-off-by: Niklas Cassel <cassel@kernel.org>

Looks OK.

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

-- 
Damien Le Moal
Western Digital Research