dracut, initramfs: Skip loading already loaded key

The user might have loaded the key manually or by other means
before the scripts get called.

Issue openzfs#9495

contrib/dracut/90zfs/mount-zfs.sh.in

@@ -62,11 +62,15 @@ if import_pool "${ZFS_POOL}" ; then
 		# if the root dataset has encryption enabled
 		ENCRYPTIONROOT="$(zfs get -H -o value encryptionroot "${ZFS_DATASET}")"
 		if ! [ "${ENCRYPTIONROOT}" = "-" ]; then
-			# decrypt them
-			ask_for_password \
-				--tries 5 \
-				--prompt "Encrypted ZFS password for ${ENCRYPTIONROOT}: " \
-				--cmd "zfs load-key '${ENCRYPTIONROOT}'"
+			KEYSTATUS="$(zfs get -H -o value keystatus "${ENCRYPTIONROOT}")"
+			# if the key needs to be loaded
+			if [ "$KEYSTATUS" = "unavailable" ]; then
+				# decrypt them
+				ask_for_password \
+					--tries 5 \
+					--prompt "Encrypted ZFS password for ${ENCRYPTIONROOT}: " \
+					--cmd "zfs load-key '${ENCRYPTIONROOT}'"
+			fi
 		fi
 	fi
 	# Let us tell the initrd to run on shutdown.

contrib/dracut/90zfs/zfs-load-key.sh.in

@@ -38,6 +38,9 @@ if [ "$(zpool list -H -o feature@encryption $(echo "${BOOTFS}" | awk -F\/ '{prin
     # if the root dataset has encryption enabled
     ENCRYPTIONROOT=$(zfs get -H -o value encryptionroot "${BOOTFS}")
     if ! [ "${ENCRYPTIONROOT}" = "-" ]; then
+	KEYSTATUS="$(zfs get -H -o value keystatus "${ENCRYPTIONROOT}")"
+	# continue only if the key needs to be loaded
+	[ "$KEYSTATUS" = "unavailable" ] || exit 0
         # decrypt them
         TRY_COUNT=5
         while [ $TRY_COUNT -gt 0 ]; do

contrib/initramfs/scripts/zfs.in

@@ -414,6 +414,9 @@ decrypt_fs()
 
 		# If root dataset is encrypted...
 		if ! [ "${ENCRYPTIONROOT}" = "-" ]; then
+			KEYSTATUS="$(${ZFS} get -H -o value keystatus "${ENCRYPTIONROOT}")"
+			# Continue only if the key needs to be loaded
+			[ "$KEYSTATUS" = "unavailable" ] || return 0
 			TRY_COUNT=3
 			# Prompt with plymouth, if active
 			if [ -e /bin/plymouth ] && /bin/plymouth --ping 2>/dev/null; then