When sd driver revalidates host-managed SMR disks, it calls
disk_set_zoned() which changes the zone_write_granularity attribute
value to the logical block size regardless of the device type. After
that, the sd driver overwrites the value in sd_zbc_read_zone() with
the physical block size, since ZBC/ZAC requires it for the host-managed
disks. Between the calls to disk_set_zoned() and sd_zbc_read_zone(),
there exists a window that the attribute shows the logical block size as
the zone_write_granularity value, which is wrong for the host-managed
disks. The duration of the window is from 20ms to 200ms, depending on
report zone command execution time.
To avoid the wrong zone_write_granularity value between disk_set_zoned()
and sd_zbc_read_zone(), modify the value not in sd_zbc_read_zone() but
just after disk_set_zoned() call.
Fixes: a805a4fa4fa3 ("block: introduce zone_write_granularity limit")
Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@xxxxxxx>
---
This patch is a repost of the second patch of another series [1]. Reviews
and comments will be welcomed.
[1] https://lore.kernel.org/linux-scsi/20230303014422.2466103-1-shinichiro.kawasaki@xxxxxxx/
drivers/scsi/sd.c | 7 ++++++-
drivers/scsi/sd_zbc.c | 8 --------
2 files changed, 6 insertions(+), 9 deletions(-)
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 4f28dd617eca..4bb87043e6db 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -2988,8 +2988,13 @@ static void sd_read_block_characteristics(struct scsi_disk *sdkp)
}
if (sdkp->device->type == TYPE_ZBC) {
- /* Host-managed */
+ /*
+ * Host-managed: Per ZBC and ZAC specifications, writes in
+ * sequential write required zones of host-managed devices must
+ * be aligned to the device physical block size.
+ */
disk_set_zoned(sdkp->disk, BLK_ZONED_HM);
+ blk_queue_zone_write_granularity(q, sdkp->physical_block_size);
} else {
sdkp->zoned = zoned;
if (sdkp->zoned == 1) {
diff --git a/drivers/scsi/sd_zbc.c b/drivers/scsi/sd_zbc.c
index 6b3a02d4406c..22801c24ea19 100644
--- a/drivers/scsi/sd_zbc.c
+++ b/drivers/scsi/sd_zbc.c
@@ -965,14 +965,6 @@ int sd_zbc_read_zones(struct scsi_disk *sdkp, u8 buf[SD_BUF_SIZE])
disk_set_max_active_zones(disk, 0);
nr_zones = round_up(sdkp->capacity, zone_blocks) >> ilog2(zone_blocks);
- /*
- * Per ZBC and ZAC specifications, writes in sequential write required
- * zones of host-managed devices must be aligned to the device physical
- * block size.
- */
- if (blk_queue_zoned_model(q) == BLK_ZONED_HM)
- blk_queue_zone_write_granularity(q, sdkp->physical_block_size);
-
sdkp->early_zone_info.nr_zones = nr_zones;
sdkp->early_zone_info.zone_blocks = zone_blocks;
--
2.38.1
