Merge branch 'topic/hanoi' of git://github.com/rdparker/zfs-auto-snapshot into hanoi

CHANGELOG

@@ -1,9 +0,0 @@
-[ 1.2.5 (Unreleased) ]
-
- * Start a changelog
- * Accept PR#94 from aimileus/macos
-   - Replace --utc longform option with -u for macos compatibility
- * Accept PR#107 from ArakniD/master
-   - Add optional label for snap removals
-
- -- Jonathan Carter 2019-09-25, 15:24 SAST

Makefile

@@ -1,28 +1,17 @@
-PREFIX := /usr/local
-
 all:
 
 install:
-	install -d $(DESTDIR)/etc/cron.d
-	install -d $(DESTDIR)/etc/cron.daily
-	install -d $(DESTDIR)/etc/cron.hourly
-	install -d $(DESTDIR)/etc/cron.weekly
-	install -d $(DESTDIR)/etc/cron.monthly
-	install -m 0644 etc/zfs-auto-snapshot.cron.frequent $(DESTDIR)/etc/cron.d/zfs-auto-snapshot
-	install etc/zfs-auto-snapshot.cron.hourly   $(DESTDIR)/etc/cron.hourly/zfs-auto-snapshot
-	install etc/zfs-auto-snapshot.cron.daily    $(DESTDIR)/etc/cron.daily/zfs-auto-snapshot
-	install etc/zfs-auto-snapshot.cron.weekly   $(DESTDIR)/etc/cron.weekly/zfs-auto-snapshot
-	install etc/zfs-auto-snapshot.cron.monthly  $(DESTDIR)/etc/cron.monthly/zfs-auto-snapshot
+	install -d $(DESTDIR)$(PREFIX)/etc/cron.d
+	install -d $(DESTDIR)$(PREFIX)/etc/cron.daily
+	install -d $(DESTDIR)$(PREFIX)/etc/cron.hourly
+	install -d $(DESTDIR)$(PREFIX)/etc/cron.weekly
+	install -d $(DESTDIR)$(PREFIX)/etc/cron.monthly
+	install etc/zfs-auto-snapshot.cron.frequent $(DESTDIR)$(PREFIX)/etc/cron.d/zfs-auto-snapshot
+	install etc/zfs-auto-snapshot.cron.hourly   $(DESTDIR)$(PREFIX)/etc/cron.hourly/zfs-auto-snapshot
+	install etc/zfs-auto-snapshot.cron.daily    $(DESTDIR)$(PREFIX)/etc/cron.daily/zfs-auto-snapshot
+	install etc/zfs-auto-snapshot.cron.weekly   $(DESTDIR)$(PREFIX)/etc/cron.weekly/zfs-auto-snapshot
+	install etc/zfs-auto-snapshot.cron.monthly  $(DESTDIR)$(PREFIX)/etc/cron.monthly/zfs-auto-snapshot
 	install -d $(DESTDIR)$(PREFIX)/share/man/man8
-	install -m 0644 src/zfs-auto-snapshot.8 $(DESTDIR)$(PREFIX)/share/man/man8/zfs-auto-snapshot.8
+	install src/zfs-auto-snapshot.8 $(DESTDIR)$(PREFIX)/share/man/man8/zfs-auto-snapshot.8
 	install -d $(DESTDIR)$(PREFIX)/sbin
 	install src/zfs-auto-snapshot.sh $(DESTDIR)$(PREFIX)/sbin/zfs-auto-snapshot
-
-uninstall:
-	rm $(DESTDIR)/etc/cron.d/zfs-auto-snapshot
-	rm $(DESTDIR)/etc/cron.hourly/zfs-auto-snapshot
-	rm $(DESTDIR)/etc/cron.daily/zfs-auto-snapshot
-	rm $(DESTDIR)/etc/cron.weekly/zfs-auto-snapshot
-	rm $(DESTDIR)/etc/cron.monthly/zfs-auto-snapshot
-	rm $(DESTDIR)$(PREFIX)/share/man/man8/zfs-auto-snapshot.8
-	rm $(DESTDIR)$(PREFIX)/sbin/zfs-auto-snapshot

README

@@ -10,12 +10,3 @@ snapshots if it is installed.
 
 This program is a posixly correct bourne shell script.  It depends only on
 the zfs utilities and cron, and can run in the dash shell.
-
-
-Installation:
--------------
-
-wget https://github.com/zfsonlinux/zfs-auto-snapshot/archive/upstream/1.2.4.tar.gz
-tar -xzf 1.2.4.tar.gz
-cd zfs-auto-snapshot-upstream-1.2.4
-make install

etc/zfs-auto-snapshot.cron.daily

@@ -1,6 +1,2 @@
 #!/bin/sh
-
-# Only call zfs-auto-snapshot if it's available
-which zfs-auto-snapshot > /dev/null || exit 0
-
 exec zfs-auto-snapshot --quiet --syslog --label=daily --keep=31 //

etc/zfs-auto-snapshot.cron.frequent

@@ -1,3 +1,3 @@
-PATH="/usr/bin:/bin:/usr/local/sbin:/usr/sbin:/sbin"
+PATH="/usr/bin:/bin:/usr/sbin:/sbin"
 
-*/15 * * * * root which zfs-auto-snapshot > /dev/null || exit 0 ; zfs-auto-snapshot --quiet --syslog --label=frequent --keep=4 //
+*/15 * * * * root zfs-auto-snapshot -q -g --label=frequent --keep=4  //

etc/zfs-auto-snapshot.cron.hourly

@@ -1,6 +1,2 @@
 #!/bin/sh
-
-# Only call zfs-auto-snapshot if it's available
-which zfs-auto-snapshot > /dev/null || exit 0
-
 exec zfs-auto-snapshot --quiet --syslog --label=hourly --keep=24 //

etc/zfs-auto-snapshot.cron.monthly

@@ -1,6 +1,2 @@
 #!/bin/sh
-
-# Only call zfs-auto-snapshot if it's available
-which zfs-auto-snapshot > /dev/null || exit 0
-
 exec zfs-auto-snapshot --quiet --syslog --label=monthly --keep=12 //

etc/zfs-auto-snapshot.cron.weekly

@@ -1,6 +1,2 @@
 #!/bin/sh
-
-# Only call zfs-auto-snapshot if it's available
-which zfs-auto-snapshot > /dev/null || exit 0
-
 exec zfs-auto-snapshot --quiet --syslog --label=weekly --keep=8 //

src/zfs-auto-snapshot.8

@@ -64,27 +64,6 @@ Snapshot named filesystem and all descendants.
 \fB\-v\fR, \fB\-\-verbose\fR
 Print info messages.
 .TP
-\fB\-\-pre-snapshot\fR=\fICOMMAND\fR
-Command to run before each dataset is snapshotted. 
-It is passed the dataset and snapshot name. If it
-returns non-zero, snapshotting this dataset is 
-aborted.
-.TP
-\fB\-\-post-snapshot\fR=\fICOMMAND\fR
-Command to run after each dataset is snapshotted. 
-It is passed the dataset and snapshot name.
-.TP
-\fB\-\-destroy-only\fR
-Do not create new snapshots, but do destroy older 
-snapshots. Has no effect unless used with \fB\-k\fR.
-.IP
-A non-obvious use may be construction of cron jobs or
-scripts that run pre-snapshot command(s), then run 
-zfs-auto-snapshot (without \fB\-k\fR) to quickly
-snapshot all datasets, then run post-snapshot
-command(s) and clean up with zfs-auto-snapshot
-\fB\-\-destroy-only\fR.
-.TP
 name
 Filesystem and volume names, or '//' for all ZFS datasets.
 .SH SEE ALSO

src/zfs-auto-snapshot.sh

@@ -39,10 +39,6 @@ opt_setauto=''
 opt_syslog=''
 opt_skip_scrub=''
 opt_verbose=''
-opt_pre_snapshot=''
-opt_post_snapshot=''
-opt_do_snapshots=1
-opt_min_size=0
 
 # Global summary statistics.
 DESTRUCTION_COUNT='0'
@@ -63,6 +59,10 @@ print_usage ()
   -n, --dry-run      Print actions without actually doing anything.
   -s, --skip-scrub   Do not snapshot filesystems in scrubbing pools.
   -h, --help         Print this usage message.
+  -H, --hanoi=INT    Use the hanoi rotation scheme.
+		     INT how frequently the hanoi rotation is being run.
+		     It is a number followed by one of w, d, h, m, s for
+		     weeks, days, hours, minutes or seconds.
   -k, --keep=NUM     Keep NUM recent snapshots and destroy older snapshots.
   -l, --label=LAB    LAB is usually 'hourly', 'daily', or 'monthly'.
   -p, --prefix=PRE   PRE is 'zfs-auto-snap' by default.
@@ -73,7 +73,6 @@ print_usage ()
   -g, --syslog       Write messages into the system log.
   -r, --recursive    Snapshot named filesystem and all descendants.
   -v, --verbose      Print info messages.
-      --destroy-only Only destroy older snapshots, do not create new ones.
       name           Filesystem and volume names, or '//' for all ZFS datasets.
 " 
 }
@@ -111,7 +110,7 @@ print_log () # level, message, ...
 			;;
 		(inf*)
 			# test -n "$opt_syslog" && logger -t "$opt_prefix" -p daemon.info $*
-			test -z "$opt_quiet" && test -n "$opt_verbose" && echo $*
+			test -n "$opt_verbose" && echo $*
 			;;
 		(deb*)
 			# test -n "$opt_syslog" && logger -t "$opt_prefix" -p daemon.debug $*
@@ -145,6 +144,123 @@ do_run () # [argv]
 }
 
 
+do_rotate () # flags, oldglob, target
+{
+	local FLAGS="$1"
+	local GLOB="$2"
+	local TARGET="$3"
+	local KEEP=''
+
+	# global DESTRUCTION_COUNT
+	# global WARNING_COUNT
+	# global SNAPSHOTS_OLD
+
+	# Retain at most $opt_keep number of old snapshots of this filesystem,
+	# including the one that was just recently created.
+	KEEP="$opt_keep"
+
+	# ASSERT: The old snapshot list is sorted by increasing age.
+	for jj in $SNAPSHOTS_OLD
+	do
+		# Check whether this is an old snapshot of the filesystem.
+		if [ -z "${jj#$TARGET@$GLOB}" ]
+		then
+			KEEP=$(( $KEEP - 1 ))
+			if [ "$KEEP" -le '0' ]
+			then
+				if do_run "zfs destroy $FLAGS '$jj'" 
+				then
+					DESTRUCTION_COUNT=$(( $DESTRUCTION_COUNT + 1 ))
+				else
+					WARNING_COUNT=$(( $WARNING_COUNT + 1 ))
+				fi
+			fi
+		fi
+	done
+}
+
+
+compute_hanoi_level() # date
+{
+	local DATE="$1"
+	local EPOCH_TIME=''
+	local HANOI_NUM=''
+	local HANOI_LEVEL='1'
+
+	# The h* is because on Solaris %H%M will have generated 12h34
+	EPOCH_TIME=$(date +%s --date="$(echo $DATE | sed 's/-\(..\)h*\(..\)$/ \1:\2/')")
+	HANOI_NUM=$(($EPOCH_TIME / $opt_hanoi));
+	while test "$HANOI_NUM" -ne "0"
+	do
+		case "${HANOI_NUM}" in
+			(*[13579])
+				break
+				;;
+		esac
+		HANOI_LEVEL=$(($HANOI_LEVEL + 1))
+		HANOI_NUM=$(($HANOI_NUM / 2))
+	done
+	echo $HANOI_LEVEL
+}
+
+
+do_hanoi () # flags, oldglob, target
+{
+	local FLAGS="$1"
+	local GLOB="$2"
+	local TARGET="$3"
+	local KEEP=''
+	local HANOI_LEVEL='0'
+	local SNAP_DATE=''
+	local SNAP_LEVEL=''
+	local POSSIBLY_DESTROY=''
+
+	# global DESTRUCTION_COUNT
+	# global WARNING_COUNT
+	# global SNAPSHOTS_OLD
+
+	HANOI_LEVEL=$(compute_hanoi_level "$DATE")
+
+	# Retain at most $opt_keep number of old snapshots of this filesystem,
+	# including the one that was just recently created.
+	KEEP="$opt_keep"
+
+	# ASSERT: The old snapshot list is sorted by increasing age.
+	for jj in $SNAPSHOTS_OLD
+	do
+		# Check whether this is an old snapshot of the filesystem.
+		if [ -z "${jj#$TARGET@$GLOB}" ]
+		then
+			# If younger snapshot was stored for possible
+			# deletion, delete it.
+			if [ -n "$POSSIBLY_DESTROY" ]
+			then
+				if do_run "zfs destroy $FLAGS '$POSSIBLY_DESTROY'"
+				then
+					DESTRUCTION_COUNT=$(( $DESTRUCTION_COUNT + 1 ))
+				else
+					WARNING_COUNT=$(( $WARNING_COUNT + 1 ))
+				fi
+				POSSIBLY_DESTROY=''
+			fi
+
+			SNAP_DATE=$(echo $jj | sed 's/.*-\(....-..-..-..h*..\)$/\1/')
+			SNAP_LEVEL=$(compute_hanoi_level "$SNAP_DATE")
+			if test "$HANOI_LEVEL" -eq "$SNAP_LEVEL"
+			then
+				# By default the hanoi rotation scheme acts as
+				# though there are an infinite number of
+				# disks.  So instead of immediately destroying
+				# this snapshot, remember it as possibly
+				# needing to be destroyed and only do so if an
+				# older snapshot is found for this set.
+				POSSIBLY_DESTROY="$jj"
+			fi
+		fi
+	done
+}
+
+
 do_snapshots () # properties, flags, snapname, oldglob, [targets...]
 {
 	local PROPS="$1"
@@ -152,71 +268,27 @@ do_snapshots () # properties, flags, snapname, oldglob, [targets...]
 	local NAME="$3"
 	local GLOB="$4"
 	local TARGETS="$5"
-	local KEEP=''
-	local RUNSNAP=1
 
-	# global DESTRUCTION_COUNT
 	# global SNAPSHOT_COUNT
 	# global WARNING_COUNT
-	# global SNAPSHOTS_OLD
 
 	for ii in $TARGETS
 	do
-                # Check if size check is > 0
-                size_check_skip=0
-                if [ "$opt_min_size" -gt 0 ]
-                then
-                        bytes_written=`zfs get -Hp -o value written $ii`
-                        kb_written=$(( $bytes_written / 1024 ))
-                        if [ "$kb_written" -lt "$opt_min_size" ]
-                        then
-                                size_check_skip=1
-                                if [ $opt_verbose -gt 0 ]
-                                then
-                                        echo "Skipping target $ii, only $kb_written kB written since last snap. opt_min_size is $opt_min_size"
-                                fi
-                        fi
-                fi
-
-                if [ -n "$opt_do_snapshots" -a "$size_check_skip" -eq 0 ]
+		if do_run "zfs snapshot $PROPS $FLAGS '$ii@$NAME'" 
 		then
-			if [ "$opt_pre_snapshot" != "" ]
-			then
-				do_run "$opt_pre_snapshot $ii $NAME" || RUNSNAP=0
-			fi
-			if [ $RUNSNAP -eq 1 ] && do_run "zfs snapshot $PROPS $FLAGS '$ii@$NAME'"
-			then
-				[ "$opt_post_snapshot" != "" ] && do_run "$opt_post_snapshot $ii $NAME"
-				SNAPSHOT_COUNT=$(( $SNAPSHOT_COUNT + 1 ))
-			else
-				WARNING_COUNT=$(( $WARNING_COUNT + 1 ))
-				continue
-			fi
+			SNAPSHOT_COUNT=$(( $SNAPSHOT_COUNT + 1 ))
+		else
+			WARNING_COUNT=$(( $WARNING_COUNT + 1 ))
+			continue
+		fi 
+
+		if test -z "$opt_hanoi"
+		then
+			test -z "$opt_keep" && continue
+			do_rotate "$FLAGS" "$GLOB" "$ii"
+		else
+			do_hanoi  "$FLAGS" "$GLOB" "$ii"
 		fi
-
-		# Retain at most $opt_keep number of old snapshots of this filesystem,
-		# including the one that was just recently created.
-		test -z "$opt_keep" && continue
-		KEEP="$opt_keep"
-
-		# ASSERT: The old snapshot list is sorted by increasing age.
-		for jj in $SNAPSHOTS_OLD
-		do
-			# Check whether this is an old snapshot of the filesystem.
-			if [ -z "${jj#$ii@$GLOB}" ]
-			then
-				KEEP=$(( $KEEP - 1 ))
-				if [ "$KEEP" -le '0' ]
-				then
-					if do_run "zfs destroy -d $FLAGS '$jj'"
-					then
-						DESTRUCTION_COUNT=$(( $DESTRUCTION_COUNT + 1 ))
-					else
-						WARNING_COUNT=$(( $WARNING_COUNT + 1 ))
-					fi
-				fi
-			fi
-		done
 	done
 }
 
@@ -224,19 +296,11 @@ do_snapshots () # properties, flags, snapname, oldglob, [targets...]
 # main ()
 # {
 
-if [ "$(uname)" = "Darwin" ]; then
-  GETOPT_BIN="$(brew --prefix gnu-getopt 2> /dev/null || echo /usr/local)/bin/getopt"
-else
-  GETOPT_BIN="getopt"
-fi
-
-GETOPT=$($GETOPT_BIN \
+GETOPT=$(getopt \
   --longoptions=default-exclude,dry-run,fast,skip-scrub,recursive \
-  --longoptions=event:,keep:,label:,prefix:,sep: \
+  --longoptions=event:,hanoi:,keep:,label:,prefix:,sep: \
   --longoptions=debug,help,quiet,syslog,verbose \
-  --longoptions=pre-snapshot:,post-snapshot:,destroy-only \
-  --longoptions=min-size: \
-  --options=dnshe:l:k:p:rs:qgvm: \
+  --options=dnshH:e:l:k:p:rs:qgv \
   -- "$@" ) \
   || exit 128
 
@@ -282,6 +346,29 @@ do
 			print_usage
 			exit 0
 			;;
+		(-H|--hanoi)
+			HANOI_OPT="$2"
+			MULT="";
+			INT="";
+			case "$2" in
+				(*[0-9]s) MULT=1 ;;
+				(*[0-9]m) MULT=60 ;;
+				(*[0-9]h) MULT=3600 ;;
+				(*[0-9]d) MULT=86400 ;;
+				(*[0-9]w) MULT=604800 ;;
+				(*)
+					print_log error "Unrecognized interval $2 for the $1 parameter."
+					exit 139
+					;;
+			esac
+			INT=$(echo $2 | sed 's/.$//')
+			if ! test "$INT" -gt '0' 2>/dev/null
+			then
+				print_log error "The $2 parameter must be a positive integer."
+			fi
+			opt_hanoi=$(($INT * $MULT))
+			shift 2
+			;;
 		(-k|--keep)
 			if ! test "$2" -gt '0' 2>/dev/null
 			then
@@ -295,10 +382,6 @@ do
 			opt_label="$2"
 			shift 2
 			;;
-		(-m|--min-size)
-			opt_min_size="$2"
-			shift 2
-			;;
 		(-p|--prefix)
 			opt_prefix="$2"
 			while test "${#opt_prefix}" -gt '0'
@@ -325,7 +408,7 @@ do
 			shift 1
 			;;
 		(--sep)
-			case "$2" in
+			case "$2" in 
 				([[:alnum:]_.:\ -])
 					:
 					;;
@@ -350,18 +433,6 @@ do
 			opt_verbose='1'
 			shift 1
 			;;
-		(--pre-snapshot)
-			opt_pre_snapshot="$2"
-			shift 2
-			;;
-		(--post-snapshot)
-			opt_post_snapshot="$2"
-			shift 2
-			;;
-		(--destroy-only)
-			opt_do_snapshots=''
-			shift 1
-			;;
 		(--)
 			shift 1
 			break
@@ -373,7 +444,7 @@ if [ "$#" -eq '0' ]
 then
 	print_log error "The filesystem argument list is empty."
 	exit 133
-fi
+fi 
 
 # Count the number of times '//' appears on the command line.
 SLASHIES='0'
@@ -388,6 +459,11 @@ then
 	exit 134
 fi
 
+if test -n "$opt_hanoi" -a -z "$opt_label"
+then
+	opt_label=hanoi
+fi
+
 # These are the only times that `zpool status` or `zfs list` are invoked, so
 # this program for Linux has a much better runtime complexity than the similar
 # Solaris implementation.
@@ -395,33 +471,16 @@ fi
 ZPOOL_STATUS=$(env LC_ALL=C zpool status 2>&1 ) \
   || { print_log error "zpool status $?: $ZPOOL_STATUS"; exit 135; }
 
-
 ZFS_LIST=$(env LC_ALL=C zfs list -H -t filesystem,volume -s name \
   -o name,com.sun:auto-snapshot,com.sun:auto-snapshot:"$opt_label") \
   || { print_log error "zfs list $?: $ZFS_LIST"; exit 136; }
 
 if [ -n "$opt_fast_zfs_list" ]
 then
-	# Check if a snapshot label is being used, in which case restrict the old
-	# snapshot removal to only snapshots with the same label format
-	if [ -n "$opt_label" ]
-	then
-		SNAPSHOTS_OLD=$(env LC_ALL=C zfs list -H -t snapshot -o name -s name | \
-			grep "$opt_prefix"_"$opt_label" | \
-			awk '{ print substr( $0, length($0) - 14, length($0) ) " " $0}' | \
-			sort -r -k1,1 -k2,2 | \
-			awk '{ print substr( $0, 17, length($0) )}') \
-	  	|| { print_log error "zfs list $?: $SNAPSHOTS_OLD"; exit 137; }
-	else
- 		SNAPSHOTS_OLD=$(env LC_ALL=C zfs list -H -t snapshot -o name -s name | \
-			grep $opt_prefix | \
-			awk '{ print substr( $0, length($0) - 14, length($0) ) " " $0}' | \
-			sort -r -k1,1 -k2,2 | \
-			awk '{ print substr( $0, 17, length($0) )}') \
-	  	|| { print_log error "zfs list $?: $SNAPSHOTS_OLD"; exit 137; }
-	fi
+	SNAPSHOTS_OLD=$(env LC_ALL=C zfs list -H -t snapshot -o name -s name|grep $opt_prefix |awk '{ print substr( $0, length($0) - 14, length($0) ) " " $0}' |sort -r -k1,1 -k2,2|awk '{ print substr( $0, 17, length($0) )}') \
+	  || { print_log error "zfs list $?: $SNAPSHOTS_OLD"; exit 137; }
 else
-        SNAPSHOTS_OLD=$(env LC_ALL=C zfs list -H -t snapshot -S creation -o name) \
+	SNAPSHOTS_OLD=$(env LC_ALL=C zfs list -H -t snapshot -S creation -o name) \
 	  || { print_log error "zfs list $?: $SNAPSHOTS_OLD"; exit 137; }
 fi
 
@@ -481,20 +540,11 @@ do
 	# Just testing "$ii" != ${ii#$jj} would incorrectly match.
 	iii="$ii/"
 
-
-	# Exclude datasets
-	# * that are not named on the command line or
-	# * those whose prefix is not on the command line (if --recursive flag is set)
+	# Exclude datasets that are not named on the command line.
 	IN_ARGS='0'
 	for jj in "$@"
 	do
-		# Ibid regarding iii.
-		jjj="$jj/"
-
 		if [ "$jj" = '//' -o "$jj" = "$ii" ]
-		then
-			IN_ARGS=$(( $IN_ARGS + 1 ))
-		elif [ -n "$opt_recursive" -a "$iii" != "${iii#$jjj}" ]
 		then
 			IN_ARGS=$(( $IN_ARGS + 1 ))
 		fi
@@ -578,43 +628,30 @@ do
 	TARGETS_RECURSIVE="${TARGETS_RECURSIVE:+$TARGETS_RECURSIVE	}$ii" # nb: \t
 done
 
+# ISO style date; fifteen characters: YYYY-MM-DD-HHMM
+# On Solaris %H%M expands to 12h34.
+DATE=$(date --utc +%F-%H%M)
+
+if test -n "$opt_hanoi" -a "$opt_event" = "-"
+then
+	opt_event=hanoi-$HANOI_OPT-level-$(compute_hanoi_level $DATE)
+fi
+
 # Linux lacks SMF and the notion of an FMRI event, but always set this property
 # because the SUNW program does. The dash character is the default.
 SNAPPROP="-o com.sun:auto-snapshot-desc='$opt_event'"
 
-# ISO style date; fifteen characters: YYYY-MM-DD-HHMM
-# On Solaris %H%M expands to 12h34.
-# We use the shortfirm -u here because --utc is not supported on macos.
-DATE=$(date -u +%F-%H%M)
-
 # The snapshot name after the @ symbol.
-SNAPNAME="${opt_prefix:+$opt_prefix$opt_sep}${opt_label:+$opt_label}-$DATE"
+SNAPNAME="$opt_prefix${opt_label:+$opt_sep$opt_label}-$DATE"
 
 # The expression for matching old snapshots.  -YYYY-MM-DD-HHMM
-SNAPGLOB="${opt_prefix:+$opt_prefix$opt_sep}${opt_label:+$opt_label}-???????????????"
+SNAPGLOB="$opt_prefix${opt_label:+?$opt_label}????????????????"
 
-if [ -n "$opt_do_snapshots" ]
-then
-	test -n "$TARGETS_REGULAR" \
-	  && print_log info "Doing regular snapshots of $TARGETS_REGULAR"
+test -n "$TARGETS_REGULAR" \
+  && print_log info "Doing regular snapshots of $TARGETS_REGULAR"
 
-	test -n "$TARGETS_RECURSIVE" \
-	  && print_log info "Doing recursive snapshots of $TARGETS_RECURSIVE"
-
-	if test -n "$opt_keep" && [ "$opt_keep" -ge "1" ]
-	then
-		print_log info "Destroying all but the newest $opt_keep snapshots of each dataset."
-	fi
-elif test -n "$opt_keep" && [ "$opt_keep" -ge "1" ]
-then
-	test -n "$TARGETS_REGULAR" \
-	  && print_log info "Destroying all but the newest $opt_keep snapshots of $TARGETS_REGULAR"
-
-	test -n "$TARGETS_RECURSIVE" \
-	  && print_log info "Recursively destroying all but the newest $opt_keep snapshots of $TARGETS_RECURSIVE"
-else
-	print_log notice "Only destroying snapshots, but count of snapshots to preserve not given. Nothing to do."
-fi
+test -n "$TARGETS_RECURSIVE" \
+  && print_log info "Doing recursive snapshots of $TARGETS_RECURSIVE"
 
 test -n "$opt_dry_run" \
   && print_log info "Doing a dry run. Not running these commands..."