Merge pull request #99 from stuehmer/patch-2

Merge changes fom master and add workaround for DASH shell problems

Makefile

@@ -11,5 +11,7 @@ install:
 	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 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

README

@@ -1,4 +1,12 @@
-An alternative implementation of the zfs-auto-snapshot service for Linux.
+zfs-auto-snapshot:
+
+An alternative implementation of the zfs-auto-snapshot service for Linux
+that is compatible with zfs-linux and zfs-fuse.
+
+Automatically create, rotate, and destroy periodic ZFS snapshots. This is
+the utility that creates the @zfs-auto-snap_frequent, @zfs-auto-snap_hourly,
+@zfs-auto-snap_daily, @zfs-auto-snap_weekly, and @zfs-auto-snap_monthly
+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.

src/zfs-auto-snapshot.8

@@ -0,0 +1,70 @@
+.TH ZFS-AUTO-SNAPSHOT "8" "June 16, 2013" "zfs-auto-snapshot.sh" "System Administration Commands"
+.SH NAME
+zfs-auto-snapshot \- take regular ZFS snapshots
+.SH SYNOPSIS
+.B zfs-auto-snapshot
+[\fIoptions\fR] [\fI-l label\fR] \fI<'//' | name \fR[\fIname\fR...]\fI>\fR
+.SH DESCRIPTION
+.B zfs-auto-snapshot
+automatically creates, rotates, and destroys snapshots for all your
+ZFS datasets, and is compatible with both zfsonlinux and zfs-fuse.
+.SH OPTIONS
+.TP
+\fB\-\-default\-exclude\fR
+By default \fBzfs-auto-snapshot\fR will snapshot all datasets except
+for those in which the user-property \fBcom.sun:auto-snapshot\fR is
+set to \fBfalse\fR.  This option reverses the behavior and requires
+\fBcom.sun:auto-snapshot\fR to be set to \fBtrue\fR.
+.TP
+\fB\-d\fR, \fB\-\-debug\fR
+Print debugging messages.
+.TP
+\fB\-e\fR, \fB\-\-event\fR=\fIEVENT\fR
+Set the com.sun:auto\-snapshot\-desc property to EVENT.
+.TP
+\fB\-\-fast\fR
+Use a faster zfs list invocation.
+.TP
+\fB\-n\fR, \fB\-\-dry\-run\fR
+Print actions without actually doing anything.
+.TP
+\fB\-s\fR, \fB\-\-skip\-scrub\fR
+Do not snapshot filesystems in scrubbing pools.
+.TP
+\fB\-h\fR, \fB\-\-help\fR
+Print the usage message.
+.TP
+\fB\-k\fR, \fB\-\-keep\fR=\fINUM\fR
+Keep NUM recent snapshots and destroy older snapshots.
+.TP
+\fB\-l\fR, \fB\-\-label\fR=\fILAB\fR
+LAB is usually 'hourly', 'daily', or 'monthly'.
+.TP
+\fB\-p\fR, \fB\-\-prefix\fR=\fIPRE\fR
+PRE is 'zfs\-auto\-snap' by default.
+.TP
+\fB\-q\fR, \fB\-\-quiet\fR
+Suppress warnings and notices at the console.
+.TP
+\fB\-\-send\-full\fR=\fIF\fR
+Send zfs full backup. Unimplemented.
+.TP
+\fB\-\-send\-incr\fR=\fIF\fR
+Send zfs incremental backup. Unimplemented.
+.TP
+\fB\-\-sep\fR=\fICHAR\fR
+Use CHAR to separate date stamps in snapshot names.
+.TP
+\fB\-g\fR, \fB\-\-syslog\fR
+Write messages into the system log.
+.TP
+\fB\-r\fR, \fB\-\-recursive\fR
+Snapshot named filesystem and all descendants.
+.TP
+\fB\-v\fR, \fB\-\-verbose\fR
+Print info messages.
+.TP
+name
+Filesystem and volume names, or '//' for all ZFS datasets.
+.SH SEE ALSO
+.BR zfs (8)

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.
@@ -29,6 +29,7 @@ opt_backup_incremental=''
 opt_default_exclude=''
 opt_dry_run=''
 opt_event='-'
+opt_fast_zfs_list=''
 opt_keep=''
 opt_label=''
 opt_prefix='zfs-auto-snap'
@@ -38,6 +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'
@@ -54,6 +58,7 @@ print_usage ()
   --default-exclude  Exclude datasets if com.sun:auto-snapshot is unset.
   -d, --debug        Print debugging messages.
   -e, --event=EVENT  Set the com.sun:auto-snapshot-desc property to EVENT.
+      --fast         Use a faster zfs list invocation.
   -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.
@@ -67,6 +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.
 " 
 }
@@ -104,7 +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 $*
@@ -146,6 +152,8 @@ do_snapshots () # properties, flags, snapname, oldglob, [targets...]
 	local GLOB="$4"
 	local TARGETS="$5"
 	local KEEP=''
+	local LABEL="$6"
+	local RUNSNAP=1
 
 	# global DESTRUCTION_COUNT
 	# global SNAPSHOT_COUNT
@@ -154,29 +162,41 @@ do_snapshots () # properties, flags, snapname, oldglob, [targets...]
 
 	for ii in $TARGETS
 	do
-		if do_run "zfs snapshot $PROPS $FLAGS '$ii@$NAME'" 
+		if [ -n "$opt_do_snapshots" ]
 		then
-			SNAPSHOT_COUNT=$(( $SNAPSHOT_COUNT + 1 ))
-		else
-			WARNING_COUNT=$(( $WARNING_COUNT + 1 ))
-			continue
-		fi 
+			if [ "$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 
+		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
+		# Match on both $GLOB *and* label.
+		while IFS='	' read -ra arrjj
 		do
 			# Check whether this is an old snapshot of the filesystem.
-			if [ -z "${jj#$ii@$GLOB}" ]
+			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 $FLAGS '$jj'" 
+					if do_run "zfs destroy -d $FLAGS '${arrjj[1]}'" 
 					then
 						DESTRUCTION_COUNT=$(( $DESTRUCTION_COUNT + 1 ))
 					else
@@ -184,7 +204,7 @@ do_snapshots () # properties, flags, snapname, oldglob, [targets...]
 					fi
 				fi
 			fi
-		done
+		done <<< "$SNAPSHOTS_OLD"
 	done
 }
 
@@ -193,9 +213,10 @@ do_snapshots () # properties, flags, snapname, oldglob, [targets...]
 # {
 
 GETOPT=$(getopt \
-  --longoptions=default-exclude,dry-run,skip-scrub,recursive \
+  --longoptions=default-exclude,dry-run,fast,skip-scrub,recursive \
   --longoptions=event:,keep:,label:,prefix:,sep: \
   --longoptions=debug,help,quiet,syslog,verbose \
+  --longoptions=pre-snapshot:,post-snapshot:,destroy-only \
   --options=dnshe:l:k:p:rs:qgv \
   -- "$@" ) \
   || exit 128
@@ -226,6 +247,10 @@ do
 			fi
 			shift 2
 			;;
+		(--fast)
+			opt_fast_zfs_list='1'
+			shift 1
+			;;
 		(-n|--dry-run)
 			opt_dry_run='1'
 			shift 1
@@ -302,6 +327,18 @@ do
 			opt_verbose='1'
 			shift 1
 			;;
+		(--pre-snapshot)
+			opt_pre_snapshot="$2"
+			shift 2
+			;;
+		(--post-snapshot)
+			opt_post_snapshot="$2"
+			shift 2
+			;;
+		(--destroy-only)
+			opt_do_snapshots=''
+			shift 1
+			;;
 		(--)
 			shift 1
 			break
@@ -335,13 +372,23 @@ fi
 ZPOOL_STATUS=$(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; }
 
-SNAPSHOTS_OLD=$(env LC_ALL=C zfs list -H -t snapshot -S creation -o name) \
-  || { print_log error "zfs list $?: $SNAPSHOTS_OLD"; exit 137; }
-
+if [ -n "$opt_fast_zfs_list" ]
+then
+ 	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 com.sun:auto-snapshot-label,name) \
+	  || { print_log error "zfs list $?: $SNAPSHOTS_OLD"; exit 137; }
+fi
 
 # Verify that each argument is a filesystem or volume.
 for ii in "$@"
@@ -358,13 +405,13 @@ do
 done
 
 # Get a list of pools that are being scrubbed.
-ZPOOLS_SCRUBBING=$(echo "$ZFS_STATUS" | awk -F ': ' \
+ZPOOLS_SCRUBBING=$(echo "$ZPOOL_STATUS" | awk -F ': ' \
   '$1 ~ /^ *pool$/ { pool = $2 } ; \
    $1 ~ /^ *scan$/ && $2 ~ /scrub in progress/ { print pool }' \
   | sort ) 
 
 # Get a list of pools that cannot do a snapshot.
-ZPOOLS_NOTREADY=$(echo "$ZFS_STATUS" | awk -F ': ' \
+ZPOOLS_NOTREADY=$(echo "$ZPOOL_STATUS" | awk -F ': ' \
   '$1 ~ /^ *pool$/ { pool = $2 } ; \
    $1 ~ /^ *state$/ && $2 !~ /ONLINE|DEGRADED/ { print pool } ' \
   | sort)
@@ -399,7 +446,8 @@ do
 	# Just testing "$ii" != ${ii#$jj} would incorrectly match.
 	iii="$ii/"
 
-	# Exclude datasets that are not named on the command line.
+
+    # Exclude datasets that are not named on the command line.
 	IN_ARGS='0'
 	for jj in "$@"
 	do
@@ -446,7 +494,7 @@ do
 		# Ibid regarding iii.
 		jjj="$jj/"
 
-		# The --recusive switch only matters for non-wild arguments.
+		# The --recursive switch only matters for non-wild arguments.
 		if [ -z "$opt_recursive" -a "$1" != '//' ]
 		then
 			# Snapshot this dataset non-recursively.
@@ -489,29 +537,46 @@ 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='$opt_event'"
+SNAPPROP="-o com.sun:auto-snapshot-desc='$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=$(date +%F-%H%M)
+DATE=$(date --utc +%F-%H%M)
 
 # 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" \
-  && print_log info "Doing regular snapshots of $TARGETS_REGULAR"
+if [ -n "$opt_do_snapshots" ]
+then
+	test -n "$TARGETS_REGULAR" \
+	  && print_log info "Doing regular snapshots of $TARGETS_REGULAR"
 
-test -n "$TARGETS_RECURSIVE" \
-  && print_log info "Doing recursive snapshots of $TARGETS_RECURSIVE"
+	test -n "$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 "$SNAPPROP" "-r" "$SNAPNAME" "$SNAPGLOB" "$TARGETS_RECURSIVE"
+do_snapshots "$SNAPPROP" ""   "$SNAPNAME" "$SNAPGLOB" "$TARGETS_REGULAR" "$opt_label"
+do_snapshots "$SNAPPROP" "-r" "$SNAPNAME" "$SNAPGLOB" "$TARGETS_RECURSIVE" "$opt_label"
 
 print_log notice "@$SNAPNAME," \
   "$SNAPSHOT_COUNT created," \