On 2020/09/28 19:12, Damien Le Moal wrote:
> On 2020/09/28 18:59, Kanchan Joshi wrote:
>> Parallel write,read,zone-mgmt operations accessing/altering zone state
>> and write-pointer may get into race. Avoid the situation by using a new
>> spinlock for zoned device.
>> Concurrent zone-appends (on a zone) returning same write-pointer issue
>> is also avoided using this lock.
>>
>> Fixes: e0489ed5daeb ("null_blk: Support REQ_OP_ZONE_APPEND")
>> Signed-off-by: Kanchan Joshi <joshi.k@xxxxxxxxxxx>
>> ---
>> drivers/block/null_blk.h | 1 +
>> drivers/block/null_blk_zoned.c | 22 ++++++++++++++++++----
>> 2 files changed, 19 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/block/null_blk.h b/drivers/block/null_blk.h
>> index daed4a9c3436..28099be50395 100644
>> --- a/drivers/block/null_blk.h
>> +++ b/drivers/block/null_blk.h
>> @@ -44,6 +44,7 @@ struct nullb_device {
>> unsigned int nr_zones;
>> struct blk_zone *zones;
>> sector_t zone_size_sects;
>> + spinlock_t zone_lock;
>>
>> unsigned long size; /* device size in MB */
>> unsigned long completion_nsec; /* time in ns to complete a request */
>> diff --git a/drivers/block/null_blk_zoned.c b/drivers/block/null_blk_zoned.c
>> index 3d25c9ad2383..e8d8b13aaa5a 100644
>> --- a/drivers/block/null_blk_zoned.c
>> +++ b/drivers/block/null_blk_zoned.c
>> @@ -45,6 +45,7 @@ int null_init_zoned_dev(struct nullb_device *dev, struct request_queue *q)
>> if (!dev->zones)
>> return -ENOMEM;
>>
>> + spin_lock_init(&dev->zone_lock);
>> if (dev->zone_nr_conv >= dev->nr_zones) {
>> dev->zone_nr_conv = dev->nr_zones - 1;
>> pr_info("changed the number of conventional zones to %u",
>> @@ -131,8 +132,11 @@ int null_report_zones(struct gendisk *disk, sector_t sector,
>> * So use a local copy to avoid corruption of the device zone
>> * array.
>> */
>> + spin_lock_irq(&dev->zone_lock);
>> memcpy(&zone, &dev->zones[first_zone + i],
>> sizeof(struct blk_zone));
>> + spin_unlock_irq(&dev->zone_lock);
>> +
>> error = cb(&zone, i, data);
>> if (error)
>> return error;
>> @@ -277,18 +281,28 @@ static blk_status_t null_zone_mgmt(struct nullb_cmd *cmd, enum req_opf op,
>> blk_status_t null_process_zoned_cmd(struct nullb_cmd *cmd, enum req_opf op,
>> sector_t sector, sector_t nr_sectors)
>> {
>> + blk_status_t sts;
>> + struct nullb_device *dev = cmd->nq->dev;
>> +
>> + spin_lock_irq(&dev->zone_lock);
>> switch (op) {
>> case REQ_OP_WRITE:
>> - return null_zone_write(cmd, sector, nr_sectors, false);
>> + sts = null_zone_write(cmd, sector, nr_sectors, false);
>> + break;
>> case REQ_OP_ZONE_APPEND:
>> - return null_zone_write(cmd, sector, nr_sectors, true);
>> + sts = null_zone_write(cmd, sector, nr_sectors, true);
>> + break;
>> case REQ_OP_ZONE_RESET:
>> case REQ_OP_ZONE_RESET_ALL:
>> case REQ_OP_ZONE_OPEN:
>> case REQ_OP_ZONE_CLOSE:
>> case REQ_OP_ZONE_FINISH:
>> - return null_zone_mgmt(cmd, op, sector);
>> + sts = null_zone_mgmt(cmd, op, sector);
>> + break;
>> default:
>> - return null_process_cmd(cmd, op, sector, nr_sectors);
>> + sts = null_process_cmd(cmd, op, sector, nr_sectors);
>> }
>> + spin_unlock_irq(&dev->zone_lock);
>> +
>> + return sts;
>> }
>>
>
> Looks good.
>
> Reviewed-by: Damien Le Moal <damien.lemoal@xxxxxxx>
Jens,
Could you queue this patch for rc2 please ?
We are seeing some issues with zone append in btrfs testing without it.
--
Damien Le Moal
Western Digital Research
