On 2020/11/04 5:52, Greg Kroah-Hartman wrote:
From: Kanchan Joshi joshi.k@samsung.com
commit 35bc10b2eafbb701064b94f283b77c54d3304842 upstream.
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.
Cc: stable@vger.kernel.org Fixes: e0489ed5daeb ("null_blk: Support REQ_OP_ZONE_APPEND") Signed-off-by: Kanchan Joshi joshi.k@samsung.com Reviewed-by: Damien Le Moal damien.lemoal@wdc.com Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
Greg,
I sent a followup patch fixing a bug introduced by this patch, but I forgot to mark it for stable. The patch is
commit aa1c09cb65e2 "null_blk: Fix locking in zoned mode"
Could you pickup that one too please ?
Best regards.
drivers/block/null_blk.h | 1 + drivers/block/null_blk_zoned.c | 22 ++++++++++++++++++---- 2 files changed, 19 insertions(+), 4 deletions(-)
--- 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 */ --- 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_dev 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 *di * So use a local copy to avoid corruption of the device zone * array. */
spin_lock_irq(&dev->zone_lock);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(struc 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;
return null_zone_write(cmd, sector, nr_sectors, true);
sts = null_zone_write(cmd, sector, nr_sectors, true);break;
return null_zone_mgmt(cmd, op, sector);
sts = null_zone_mgmt(cmd, op, sector);break;
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;
}