[PATCH v2] scsi: scsi_debug: Zero clear zones at reset write pointer

[Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>]

When reset write pointer is requested to scsi_debug devices with zoned
model, positions of write pointers are reset, but the data in the target
zones are not cleared. Read to the zones returns data written before the
reset write pointer. This unexpected left data is confusing and does not
allow using scsi_debug for stale page cache test of the BLKRESETZONE
ioctl. Hence, zero clear the written data in the zones at reset write
pointer.

Fixes: f0d1cf9378bd ("scsi: scsi_debug: Add ZBC zone commands")
Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
---
Changes from v1:
* Zero clear only the written data area in non-empty zones

 drivers/scsi/scsi_debug.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index 1d0278da9041..1ef9907c479a 100644
--- a/drivers/scsi/scsi_debug.c
+++ b/drivers/scsi/scsi_debug.c
@@ -4653,6 +4653,7 @@ static void zbc_rwp_zone(struct sdebug_dev_info *devip,
 			 struct sdeb_zone_state *zsp)
 {
 	enum sdebug_z_cond zc;
+	struct sdeb_store_info *sip = devip2sip(devip, false);
 
 	if (zbc_zone_is_conv(zsp))
 		return;
@@ -4664,6 +4665,10 @@ static void zbc_rwp_zone(struct sdebug_dev_info *devip,
 	if (zsp->z_cond == ZC4_CLOSED)
 		devip->nr_closed--;
 
+	if (zsp->z_wp > zsp->z_start)
+		memset(sip->storep + zsp->z_start * sdebug_sector_size, 0,
+		       (zsp->z_wp - zsp->z_start) * sdebug_sector_size);
+
 	zsp->z_non_seq_resource = false;
 	zsp->z_wp = zsp->z_start;
 	zsp->z_cond = ZC1_EMPTY;
-- 
2.33.1