Add --no-bookmark flag

This prevents the use bookmarks when trying to find the latest common
snapshot. This forces a rollback when the latest snapshot on the source
was deleted but a common and older snapshot was found.

Signed-off-by: Felix Matouschek <felix@matouschek.org>

syncoid

@@ -24,7 +24,7 @@ my %args = ('sshconfig' => '', 'sshkey' => '', 'sshport' => '', 'sshcipher' => '
 GetOptions(\%args, "no-command-checks", "monitor-version", "compress=s", "dumpsnaps", "recursive|r", "sendoptions=s", "recvoptions=s",
                    "source-bwlimit=s", "target-bwlimit=s", "sshconfig=s", "sshkey=s", "sshport=i", "sshcipher|c=s", "sshoption|o=s@",
                    "debug", "quiet", "no-stream", "no-sync-snap", "no-resume", "exclude=s@", "skip-parent", "identifier=s",
-                   "no-clone-handling", "no-privilege-elevation", "force-delete", "no-rollback", "create-bookmark", "use-hold",
+                   "no-clone-handling", "no-privilege-elevation", "force-delete", "no-rollback", "create-bookmark", "no-bookmark", "use-hold",
                    "pv-options=s" => \$pvoptions, "keep-sync-snap", "preserve-recordsize", "mbuffer-size=s" => \$mbuffer_size,
                    "delete-target-snapshots", "insecure-direct-connection=s", "preserve-properties",
                    "include-snaps=s@", "exclude-snaps=s@", "exclude-datasets=s@")
@@ -609,6 +609,7 @@ sub syncdataset {
 		my %bookmark = ();
 		my $bookmarksnap = 0;
 
+		if (! defined $args{'no-bookmark'}) {
 			# find most recent matching bookmark
 			my %bookmarks = getbookmarks($sourcehost,$sourcefs,$sourceisroot);
 
@@ -623,6 +624,7 @@ sub syncdataset {
 					last;
 				}
 			}
+		}
 
 		$matchingsnap = getmatchingsnapshot($sourcefs, $targetfs, \%snaps);
 		if (! $matchingsnap) {
@@ -2439,6 +2441,7 @@ Options:
   --no-sync-snap        Does not create new snapshot, only transfers existing
   --keep-sync-snap      Don't destroy created sync snapshots
   --create-bookmark     Creates a zfs bookmark for the newest snapshot on the source after replication succeeds (only works with --no-sync-snap)
+  --no-bookmark         Do not use bookmarks when trying to find the latest common snapshot. This forces a rollback when the latest snapshot on the source was deleted but a common and older snapshot was found.
   --use-hold            Adds a hold to the newest snapshot on the source and target after replication succeeds and removes the hold after the next successful replication. The hold name includes the identifier if set. This allows for separate holds in case of multiple targets
   --preserve-recordsize Preserves the recordsize on initial sends to the target
   --preserve-properties Preserves locally set dataset properties similar to the zfs send -p flag but this one will also work for encrypted datasets in non raw sends

tests/syncoid/016_require_rollback_when_not_using_bookmarks/run.sh

@@ -0,0 +1,62 @@
+#!/bin/bash
+
+# test that a rollback is required when not using bookmarks
+
+set -x
+set -e
+
+. ../../common/lib.sh
+
+POOL_IMAGE="/tmp/syncoid-test-016.zpool"
+MOUNT_TARGET="/tmp/syncoid-test-016.mount"
+POOL_SIZE="1000M"
+POOL_NAME="syncoid-test-016"
+TARGET_CHECKSUM="0ed2eed1488bbba5c35c2b24beee9e6e8a76f8de10aa1e3710dc737cf626635a  -"
+
+truncate -s "${POOL_SIZE}" "${POOL_IMAGE}"
+
+zpool create -m "${MOUNT_TARGET}" -f "${POOL_NAME}" "${POOL_IMAGE}"
+
+function cleanUp {
+  zpool export "${POOL_NAME}"
+}
+
+# export pool in any case
+trap cleanUp EXIT
+
+zfs create "${POOL_NAME}"/a
+zfs snapshot "${POOL_NAME}"/a@s0
+
+# This fully replicates a to b
+../../../syncoid --debug --no-sync-snap --no-rollback --create-bookmark "${POOL_NAME}"/a "${POOL_NAME}"/b
+
+echo "Test 1" > "${MOUNT_TARGET}"/a/file1
+zfs snapshot "${POOL_NAME}"/a@s1
+
+# This incrementally replicates from a@s0 to a@s1
+../../../syncoid --debug --no-sync-snap --no-rollback --create-bookmark "${POOL_NAME}"/a "${POOL_NAME}"/b
+
+echo "Test 2" > "${MOUNT_TARGET}"/a/file2
+zfs snapshot "${POOL_NAME}"/a@s2
+
+# Destroy latest common snap between a and b
+zfs destroy "${POOL_NAME}"/a@s1
+
+# This uses a@s0 and rolls b back to it although common and newer bookmark a#s1 exists
+../../../syncoid --debug --no-sync-snap --no-bookmark --create-bookmark "${POOL_NAME}"/a "${POOL_NAME}"/b
+
+echo "Test 3" > "${MOUNT_TARGET}"/a/file3
+zfs snapshot "${POOL_NAME}"/a@s3
+
+# This uses a@s2 as base snap again
+../../../syncoid --debug --no-sync-snap --no-rollback --create-bookmark "${POOL_NAME}"/a "${POOL_NAME}"/b
+
+# verify
+output=$(zfs list -t snapshot -r -H -o name "${POOL_NAME}")
+checksum=$(echo "${output}" | shasum -a 256)
+
+if [ "${checksum}" != "${TARGET_CHECKSUM}" ]; then
+  exit 1
+fi
+
+exit 0