[slx-dmsetup] more work towards persistent thin pool

1 files changed, 11 insertions, 15 deletions

diff --git a/modules.d/slx-dmsetup/scripts/dmsetup-slx-device b/modules.d/slx-dmsetup/scripts/dmsetup-slx-device
index 6ee810c4..56ea3172 100755
--- a/modules.d/slx-dmsetup/scripts/dmsetup-slx-device
+++ b/modules.d/slx-dmsetup/scripts/dmsetup-slx-device
@@ -356,7 +356,6 @@ writable_device_size="$scratch_device_size"
 ### 
 ##	THIN-PROVISIONING
 ###
-declare -rg pool_metadata_dev="/dev/mapper/pool-metadata"
 declare -rg pool_data_dev="/dev/mapper/pool-data"
 declare -rg pool_dev="/dev/mapper/pool"
 create_pool() {
@@ -371,39 +370,36 @@ create_pool() {
 	[ "$metadata_dev_size" -lt 4096 ] && metadata_dev_size="4096"
 	# TODO handle the exotic case of a too large metadata device to fit within RAM.
 	[ "$metadata_dev_size" -gt 33554432 ] && metadata_dev_size="33554432"
-	# TODO handle persistent metadata device on disk
+	local writable_device_offset=0
 	local metadata_dev=
-	local metadata_volatile="yes"
-	if [ -z "$metadata_volatile" ]; then
+	local metadata_persistent=
+	if [ -n "$metadata_persistent" ]; then
 		# create persistent slice of the writable device for the pool metadata
-		if ! dmsetup_create_noudevsync "metadata" \
-			"0 $metadata_dev_size linear $writable_device 0"; then
+		if ! dmsetup_create_noudevsync "pool-metadata" \
+			"0 $metadata_dev_size linear $writable_device $writable_device_offset"; then
 			echo "$0: Failed to create linear device for pool metadata device."
 		else
-			metadata_dev="/dev/mapper/metadata"
+			writable_device_offset="$metadata_dev_size"
 			writable_device_size=$(( $writable_device_size - $metadata_dev_size ))
+			declare -r metadata_dev="/dev/mapper/pool-metadata"
+			# TODO configurable wipe: dd if=/dev/zero of="$metadata_dev" count=1 bs=4096
 		fi
 	fi
 	if [ -z "$metadata_dev" ]; then
 		# create RAMdisk in /run for metadata device
 		metadata_dev="$(mktemp -p /run/openslx .pool-metadata.XXX)"
 		dd of="$metadata_dev" bs=512 seek="$metadata_dev_size" &> /dev/null
-		metadata_dev="$(losetup --show --find $metadata_dev)"
-	fi
-	if ! dmsetup_create_noudevsync "${pool_metadata_dev##*/}" \
-		"0 $metadata_dev_size linear $metadata_dev 0"; then
-		echo "$0: Failed to create pool metadata device on '$writable_device'."
-		return 1
+		declare -r metadata_dev="$(losetup --show --find $metadata_dev)"
 	fi
 
 	if ! dmsetup_create_noudevsync "${pool_data_dev##*/}" \
-		"0 $writable_device_size linear $writable_device 0"; then
+		"0 $writable_device_size linear $writable_device $writable_device_offset"; then
 		echo "$0: Failed to create pool data device on '$writable_device'."
 		return 1
 	fi
 	low_water_mark=32
 	if ! dmsetup_create_noudevsync "${pool_dev##*/}" \
-		"0 $writable_device_size thin-pool $pool_metadata_dev $pool_data_dev $data_block_size $low_water_mark"; then
+		"0 $writable_device_size thin-pool $metadata_dev $pool_data_dev $data_block_size $low_water_mark"; then
 		echo "$0: Failed to create thin-pool device on '$writable_device'."
 		return 1
 	fi