From 881f9ace728c7108c0e91dad1d85558f6ec12fc5 Mon Sep 17 00:00:00 2001
From: Tamas Gerczei <tamas@gerczei.eu>
Date: Thu, 8 Aug 2019 10:21:39 +0200
Subject: [PATCH] will now receive with the '-s' flag to enable resuming
 provided the system supports it

---
 zfs-backup.sh | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/zfs-backup.sh b/zfs-backup.sh
index c770931..2d1a7bc 100755
--- a/zfs-backup.sh
+++ b/zfs-backup.sh
@@ -107,7 +107,7 @@ function backup() {
 																		R_SNAPMODIFIER="I $(dirname ${DATASET})/$(basename ${R_SNAPSHOTS[*]:(-1)})"
 																fi
 																# send any previous snapshots
-																/usr/sbin/zfs send -R${RAW_MOD}${R_SNAPMODIFIER} ${LASTSNAP} | ${RMOD} /usr/sbin/zfs recv -Feuv ${SAVETO} 2>&1 >> ${LOGFILE}
+																/usr/sbin/zfs send -R${RAW_MOD}${R_SNAPMODIFIER} ${LASTSNAP} | ${RMOD} /usr/sbin/zfs recv -Feu${RESUME_MOD}v ${SAVETO} 2>&1 >> ${LOGFILE}
 																}
 		else
 			# ensure this does not remain in effect
@@ -115,7 +115,7 @@ function backup() {
 	fi
 	
 	# send backup
-	/usr/sbin/zfs send -R${RAW_MOD}${SNAPMODIFIER} ${NEWSNAP} | ${RMOD} /usr/sbin/zfs recv -Feuv ${SAVETO} 2>&1 >> ${LOGFILE}
+	/usr/sbin/zfs send -R${RAW_MOD}${SNAPMODIFIER} ${NEWSNAP} | ${RMOD} /usr/sbin/zfs recv -Feu${RESUME_MOD}v ${SAVETO} 2>&1 >> ${LOGFILE}
 	
 	# if replication is unsuccessful, omit the aging check so as to prevent data loss
 	if [ $? -eq 0 ]
@@ -233,6 +233,21 @@ if [[ "$PLATFORM_VERSION" =~ ^joyent ]]
 				logger -t $(basename ${0%.sh}) -p user.notice "ZFS encryption is not supported on $PLATFORM_VERSION"
 				ENCRYPTION_FEATURE="disabled"
 		fi
+
+		EXTENSION_FEATURE=$(/usr/sbin/zpool get -Ho value feature@extensible_dataset ${POOL_NAME})
+		if [ $? -ne 0 ]
+			then
+				# feature unknown, outdated PI
+				logger -t $(basename ${0%.sh}) -p user.notice "extensible datasets are not supported on $PLATFORM_VERSION"
+				EXTENSION_FEATURE="disabled"
+			else
+				# check if resuming is supported
+				if [ $EXTENSION_FEATURE == "active" ]
+					then
+						# extensible_dataset feature available
+						RESUME_MOD="s"
+				fi
+		fi
 fi
 
 # determine current timestamp