Re: [PATCH v2 5/8] zbd: add the recover_zbd_write_error option

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

On 4/25/25 2:21 PM, Shin'ichiro Kawasaki wrote:
> When the continue_on_error options is specified, it is expected that the
> workload continues to run when non-critical errors happen. However,
> write workloads with zonemode=zbd option can not continue after errors,
> if the failed writes cause partial data write on the target device. This
> partial write creates write pointer gap between the device and fio, then
> the next write requests by fio will fail due to unaligned write command
> errors. This restriction results in undesirable test stops during long
> runs for SMR drives which can recover defect sectors.
> 
> To allow the write workloads with zonemode=zbd to continue after write
> failures with partial data writes, introduce the new option
> recover_zbd_write_error. When this option is specified together with the
> continue_on_error option, fio checks the write pointer positions of the
> write target zones in the error handling step. Then fix the write
> pointer by moving it to the position that the failed writes would have
> moved. Bump up FIO_SERVER_VER to note that the new option is added.
> 
> For that purpose, add a new function zbd_recover_write_error(). Call it
> from zbd_queue_io() for sync IO engines, and from io_completed() for
> async IO engines. Modify zbd_queue_io() to pass the pointer to the
> status so that zbd_recover_write_error() can modify the status to ignore
> the errors. Add three fields to struct fio_zone_info. The two new fields
> writes_in_flight and max_write_error_offset track status of in-flight
> writes at the write error, so that the write pointer positions can be
> fixed after the in-flight writes completed. The field fixing_zone_wp
> stores that the write pointer fix is ongoing, then prohibit the new
> writes get issued to the zone.
> 
> When the failed write is synchronous, the write pointer fix is done by
> writing the left data for the failed write. This keeps the verify
> patterns written to the device, then verify works together with the
> continue_on_zbd_write_error option. When the failed write is
> asynchronous, other in-flight writes fail together. In this case, fio
> waits for all in-flight writes complete then fix the write pointer. Then
> verify data of the failed writes are lost and verify does not work.
> Check the continue_on_zbd_write_error option is not specified together
> with the verify workload and asynchronous IO engine.
> 
> Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>

Looks OK to me.

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


-- 
Damien Le Moal
Western Digital Research