Merge pull request #99 from stuehmer/patch-2

Merge changes fom master and add workaround for DASH shell problems

src/zfs-auto-snapshot.sh

@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/bin/bash
 
 # zfs-auto-snapshot for Linux
 # Automatically create, rotate, and destroy periodic ZFS snapshots.
@@ -39,6 +39,9 @@ opt_setauto=''
 opt_syslog=''
 opt_skip_scrub=''
 opt_verbose=''
+opt_pre_snapshot=''
+opt_post_snapshot=''
+opt_do_snapshots=1
 
 # Global summary statistics.
 DESTRUCTION_COUNT='0'
@@ -59,10 +62,6 @@ 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.
@@ -73,6 +72,7 @@ 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.
 " 
 }
@@ -110,7 +110,7 @@ print_log () # level, message, ...
 			;;
 		(inf*)
 			# test -n "$opt_syslog" && logger -t "$opt_prefix" -p daemon.info $*
-			test -n "$opt_verbose" && echo $*
+			test -z ${opt_quiet+x} && test -n "$opt_verbose" && echo $*
 			;;
 		(deb*)
 			# test -n "$opt_syslog" && logger -t "$opt_prefix" -p daemon.debug $*
@@ -144,123 +144,6 @@ 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"
@@ -268,27 +151,60 @@ do_snapshots () # properties, flags, snapname, oldglob, [targets...]
 	local NAME="$3"
 	local GLOB="$4"
 	local TARGETS="$5"
+	local KEEP=''
+	local LABEL="$6"
+	local RUNSNAP=1
 
+	# global DESTRUCTION_COUNT
 	# global SNAPSHOT_COUNT
 	# global WARNING_COUNT
+	# global SNAPSHOTS_OLD
 
 	for ii in $TARGETS
 	do
-		if do_run "zfs snapshot $PROPS $FLAGS '$ii@$NAME'" 
+		if [ -n "$opt_do_snapshots" ]
 		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 $NAME"
 				SNAPSHOT_COUNT=$(( $SNAPSHOT_COUNT + 1 ))
 			else
 				WARNING_COUNT=$(( $WARNING_COUNT + 1 ))
 				continue
 			fi 
-
-		if test -z "$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.
+		# Match on both $GLOB *and* label.
+		while IFS='	' read -ra arrjj
+		do
+			# Check whether this is an old snapshot of the filesystem.
+			if [ -z "${arrjj[1]#$ii@$GLOB}" ]
+			then
+				# Check whether the snapshot has the same label property
+				test "${arrjj[0]}" = "$LABEL" || continue
+			
+				KEEP=$(( $KEEP - 1 ))
+				if [ "$KEEP" -le '0' ]
+				then
+					if do_run "zfs destroy -d $FLAGS '${arrjj[1]}'" 
+					then
+						DESTRUCTION_COUNT=$(( $DESTRUCTION_COUNT + 1 ))
+					else
+						WARNING_COUNT=$(( $WARNING_COUNT + 1 ))
+					fi
+				fi
+			fi
+		done <<< "$SNAPSHOTS_OLD"
 	done
 }
 
@@ -298,9 +214,10 @@ do_snapshots () # properties, flags, snapname, oldglob, [targets...]
 
 GETOPT=$(getopt \
   --longoptions=default-exclude,dry-run,fast,skip-scrub,recursive \
-  --longoptions=event:,hanoi:,keep:,label:,prefix:,sep: \
+  --longoptions=event:,keep:,label:,prefix:,sep: \
   --longoptions=debug,help,quiet,syslog,verbose \
-  --options=dnshH:e:l:k:p:rs:qgv \
+  --longoptions=pre-snapshot:,post-snapshot:,destroy-only \
+  --options=dnshe:l:k:p:rs:qgv \
   -- "$@" ) \
   || exit 128
 
@@ -346,29 +263,6 @@ 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
@@ -433,6 +327,18 @@ 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
@@ -459,11 +365,6 @@ 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.
@@ -471,16 +372,21 @@ 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 "$opt_fast_zfs_list" ]
 then
-	SNAPSHOTS_OLD=$(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($0) )}') \
+ 	SNAPSHOTS_OLD=$(env LC_ALL=C zfs list -H -t snapshot -o com.sun:auto-snapshot-label,name -s name | \
+		grep $opt_prefix | \
+		awk '{ print substr( $0, length($0) - 14, length($0) ) " " $0}' | \
+		sort -r -k1,1 -k3,2 | \
+		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 com.sun:auto-snapshot-label,name) \
 	  || { print_log error "zfs list $?: $SNAPSHOTS_OLD"; exit 137; }
 fi
 
@@ -540,6 +446,7 @@ do
 	# Just testing "$ii" != ${ii#$jj} would incorrectly match.
 	iii="$ii/"
 
+
     # Exclude datasets that are not named on the command line.
 	IN_ARGS='0'
 	for jj in "$@"
@@ -628,36 +535,48 @@ do
 	TARGETS_RECURSIVE="${TARGETS_RECURSIVE:+$TARGETS_RECURSIVE	}$ii" # nb: \t
 done
 
+# 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='$opt_event' -o com.sun:auto-snapshot-label=$opt_label"
+
 # 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'"
-
 # The snapshot name after the @ symbol.
-SNAPNAME="$opt_prefix${opt_label:+$opt_sep$opt_label}-$DATE"
+SNAPNAME="$opt_prefix$opt_sep$DATE"
 
 # The expression for matching old snapshots.  -YYYY-MM-DD-HHMM
-SNAPGLOB="$opt_prefix${opt_label:+?$opt_label}????????????????"
+SNAPGLOB="${opt_prefix}????????????????"
 
-test -n "$TARGETS_REGULAR" \
+if [ -n "$opt_do_snapshots" ]
+then
+	test -n "$TARGETS_REGULAR" \
 	  && print_log info "Doing regular snapshots of $TARGETS_REGULAR"
 
-test -n "$TARGETS_RECURSIVE" \
+	test -n "$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 $TARGETS_RECURSIVE"
+else
+	print_log notice "Only destroying snapshots, but count of snapshots to preserve not given. Nothing to do."
+fi
+
 test -n "$opt_dry_run" \
   && print_log info "Doing a dry run. Not running these commands..."
 
-do_snapshots "$SNAPPROP" ""   "$SNAPNAME" "$SNAPGLOB" "$TARGETS_REGULAR"
+do_snapshots "$SNAPPROP" ""   "$SNAPNAME" "$SNAPGLOB" "$TARGETS_REGULAR" "$opt_label"
-do_snapshots "$SNAPPROP" "-r" "$SNAPNAME" "$SNAPGLOB" "$TARGETS_RECURSIVE"
+do_snapshots "$SNAPPROP" "-r" "$SNAPNAME" "$SNAPGLOB" "$TARGETS_RECURSIVE" "$opt_label"
 
 print_log notice "@$SNAPNAME," \
   "$SNAPSHOT_COUNT created," \