[slx-dmsetup] preparations for persistent metadata device for thin-pool

1 files changed, 14 insertions, 6 deletions

diff --git a/modules.d/slx-dmsetup/scripts/dmsetup-slx-device b/modules.d/slx-dmsetup/scripts/dmsetup-slx-device
index 7a371123..8ec34fdc 100755
--- a/modules.d/slx-dmsetup/scripts/dmsetup-slx-device
+++ b/modules.d/slx-dmsetup/scripts/dmsetup-slx-device
@@ -327,17 +327,25 @@ create_pool() {
 	# TODO handle the exotic case of a too large metadata device to fit within RAM.
 	[ "$metadata_dev_size" -gt 33554432 ] && metadata_dev_size="33554432"
 	# TODO handle persistent metadata device on disk
-	# create RAMdisk in /run for metadata device
-	metadata_dev="$(mktemp -p /run/openslx .pool-metadata.XXX)"
-	dd of="$metadata_dev" bs=512 seek="$metadata_dev_size" &> /dev/null
-	metadata_dev="$(losetup --show --find $metadata_dev)"
+	local metadata_volatile="yes"
+	if [ -n "$metadata_volatile" ]; 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)"
+	else
+		# create persistent slice of the writable device for the pool metadata
+		if ! dmsetup_create_noudevsync "metadata" \
+			"0 $metadata_dev_size linear $writable_device 0"; then
+		fi
+		metadata_dev="/dev/mapper/metadata"
+		writable_device_size=$(( $writable_device_size - $metadata_dev_size ))
+	fi
 	if ! dmsetup_create_noudevsync "${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
 	fi
-	# For persistent metadata device we will need to cut that space off first:
-	# writable_device_size=$(( $writable_device_size - $metadata_dev_size ))
 
 	if ! dmsetup_create_noudevsync "${pool_data_dev##*/}" \
 		"0 $writable_device_size linear $writable_device 0"; then