[PATCH v3 3/6] t/zbd: Mandate blkzone capacity report for devices with zone capacity

["Shin'ichiro Kawasaki" <shinichiro.kawasaki@xxxxxxx>]

For NVMe ZNS and null_blk zoned drives, a zone capacity can be smaller
than its size. To test zone capacity handling by fio for these devices,
t/zbd/test-zbd-support must be able to discover zone capacities to avoid
test failures.

To avoid the failures, make zone capacity report by blkzone mandatory if
the test target device is a ZNS device or a null_blk device.

Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@xxxxxxx>
---
 t/zbd/functions        | 45 ++++++++++++++++++++++++++++++++++++++++++
 t/zbd/test-zbd-support |  3 +++
 2 files changed, 48 insertions(+)

diff --git a/t/zbd/functions b/t/zbd/functions
index 1bd22ec4..14366e15 100644
--- a/t/zbd/functions
+++ b/t/zbd/functions
@@ -19,6 +19,51 @@ if [ -n "${use_libzbc}" ] &&
     exit 1
 fi
 
+blkzone_reports_capacity() {
+	local dev="${1}"
+
+	[[ -n "${blkzone}" ]] &&
+		"${blkzone}" report -c 1 -o 0 "${dev}" | grep -q 'cap '
+}
+
+# Whether or not $1 (/dev/...) is a NVME ZNS device.
+is_nvme_zns() {
+	local s
+
+	s=/sys/block/$(basename "${1}")/device/subsystem
+
+	if [[ ! -h "${s}" || $(realpath "${s}") != /sys/class/nvme ]]; then
+		return 1
+	fi
+
+	[[ $(</sys/block/$(basename "${1}")/queue/zoned) == host-managed ]]
+}
+
+# Whether or not $1 (/dev/...) is a null_blk device with zone capacity smaller
+# than zone size.
+is_nullb_with_zone_cap() {
+	local f
+
+	f=/sys/kernel/config/nullb/$(basename "${1}")
+	[[ -r "${f}/zone_capacity" &&
+		   $(<"${f}/zone_capacity") -lt $(<"${f}/zone_size") ]]
+}
+
+# Check if blkzone is available and suitable for the test target device. If not
+# available, print error message and return 1. Otherwise return 0.
+check_blkzone() {
+	local dev="${1}"
+
+	# If the device supports zone capacity, mandate zone capacity report by
+	# blkzone.
+	if (is_nvme_zns "${dev}" || is_nullb_with_zone_cap "${dev}") &&
+				! blkzone_reports_capacity "${dev}"; then
+		echo "Error: blkzone does not report zone capacity"
+		echo "Error: install latest util-linux with blkzone"
+		return 1
+	fi
+}
+
 # Reports the starting sector and length of the first sequential zone of device
 # $1.
 first_sequential_zone() {
diff --git a/t/zbd/test-zbd-support b/t/zbd/test-zbd-support
index 80dc3f30..f086bd10 100755
--- a/t/zbd/test-zbd-support
+++ b/t/zbd/test-zbd-support
@@ -863,6 +863,9 @@ if [[ -b "$realdev" ]]; then
 	case "$(<"/sys/class/block/$basename/queue/zoned")" in
 	host-managed|host-aware)
 		is_zbd=true
+		if ! check_blkzone "${dev}"; then
+			exit 1
+		fi
 		if ! result=($(first_sequential_zone "$dev")); then
 			echo "Failed to determine first sequential zone"
 			exit 1
-- 
2.26.2