Check whether we have zfs-auto-snapshot before running it

zfs destroy will use -d for deferred destruction

debian/changelog

@@ -1,100 +0,0 @@
-zfs-auto-snapshot (1.2.0-1) unstable; urgency=low
-
-  [ Roland Stühmer ]
-  * Fix SNAPNAME to contain the DATE if label is empty
-
-  [ Borut Mrak ]
-  * Remove PREFIX from cron scripts - they should always end up in /etc.
-  * Leave PREFIX for man page and program, and set it to /usr/local by default.
-
-  [ Maciej Małecki ]
-  * Add `--{pre,post}-snapshot` for pre and post creation hook
-  * Abort if pre snapshot hook returns non-zero
-  * Document `--{pre,post}-snapshot
-
-  [ Mike Baynton ]
-  * Make --{pre,post}-snapshot optional, add --destroy-only, revise docs
-
-  [ virtualguy ]
-  * Update README
-
-  [ Darik Horn ]
-  * Install the cron.d part without the execute bit.
-  * Update debian/rules for Makefile changes.
-
- -- Darik Horn <dajhorn@vanadac.com>  Mon, 13 Oct 2014 23:17:30 -0500
-
-zfs-auto-snapshot (1.1.0-0ubuntu1) unstable; urgency=low
-
-  [ Markus Heberling ]
-  * Use only name property for zfs list
-
-  [ Darik Horn ]
-  * Add a switch for the fast zfs list invocation.
-
-  [ Mike Swanson ]
-  * Add a manpage
-  * Update Makefile for the manual page
-
-  [ HawkOwl ]
-  * Set the snapshots to use UTC time, which makes the date/time display correctly in Windows 7 Previous Versions.
-
- -- Darik Horn <dajhorn@vanadac.com>  Mon, 31 Mar 2014 01:48:58 -0500
-
-zfs-auto-snapshot (1.0.8-0ubuntu2) unstable; urgency=low
-
-  * Update the debian/control file.
-
- -- Darik Horn <dajhorn@vanadac.com>  Sun, 31 Mar 2013 23:10:55 -0500
-
-zfs-auto-snapshot (1.0.8-0ubuntu1) unstable; urgency=low
-
-  * Update the README file to be more descriptive.
-  * Fix pool exclusions.
-
- -- Darik Horn <dajhorn@vanadac.com>  Sat, 21 Jan 2012 16:37:28 -0600
-
-zfs-auto-snapshot (1.0.7-0ubuntu1) unstable; urgency=low
-
-  [ Darik Horn ]
-  * Change objects to datasets in help and comments.
-  * Set keep=8 in the weekly cron job.
-
-  [ Ulrich Petri ]
-  * Fixed --prefix and --sep regexes
-
- -- Darik Horn <dajhorn@vanadac.com>  Wed, 28 Dec 2011 13:30:02 -0600
-
-zfs-auto-snapshot (1.0.6-0ubuntu1) unstable; urgency=low
-
-  * Remove redundant lines in the cron.d file.
-  * Fix the hourly-daily transposition in the Makefile.
-
- -- Darik Horn <dajhorn@vanadac.com>  Mon, 28 Nov 2011 00:10:05 -0600
-
-zfs-auto-snapshot (1.0.5-0ubuntu1) unstable; urgency=low
-
-  * Split the cron file for anacron compatibilty.
-
- -- Darik Horn <dajhorn@vanadac.com>  Fri, 25 Nov 2011 14:28:07 -0600
-
-zfs-auto-snapshot (1.0.4-0ubuntu1) unstable; urgency=low
-
-  * Invert the --skip-scrub test.
-  * Fold the main loops into a do_snapshots function.
-  * Consistently quote literal strings.
-  * Implement --prefix parameter checking.
-  * Rebase exit codes to above 127.
-  * Implement the --event option for :auto-snap-desc.
-
- -- Darik Horn <dajhorn@vanadac.com>  Wed, 23 Nov 2011 10:49:14 -0600
-
-zfs-auto-snapshot (1.0.3-0ubuntu1) unstable; urgency=low
-
-  * Add -q to the getopt list of short options.
-  * Add an explicit `exit 0` to the end of the script.
-  * Add gbp.conf file for git-buildpackage.
-  * Expand the options variable in the cron part file.
-  * Initial debian packaging.
-
- -- Darik Horn <dajhorn@vanadac.com>  Mon, 21 Nov 2011 21:52:11 -0600

debian/compat

@@ -1 +0,0 @@
-7

debian/control

@@ -1,16 +0,0 @@
-Source: zfs-auto-snapshot
-Section: admin
-Priority: extra
-Maintainer: Darik Horn <dajhorn@vanadac.com>
-Build-Depends: debhelper (>= 8)
-Standards-Version: 3.9.4
-Homepage: http://www.zfsonlinux.org/
-Vcs-Git: git://github.com/zfsonlinux/zfs-auto-snapshot.git
-Vcs-Browser: https://github.com/zfsonlinux/zfs-auto-snapshot/
-
-Package: zfs-auto-snapshot
-Architecture: all
-Depends: ${misc:Depends}, cron, zfsutils
-Description: ZFS Automatic Snapshot Service
- Automatically create and destroy ZFS snapshots on an hourly, daily, weekly
- and monthly schedule.

debian/copyright

@@ -1 +0,0 @@
-Copyright 2011 Darik Horn <dajhorn@vanadac.com>

debian/gbp.conf

@@ -1,3 +0,0 @@
-[DEFAULT]
-upstream-branch = master
-debian-branch = debian

debian/rules

@@ -1,7 +0,0 @@
-#!/usr/bin/make -f
-
-%:
-	dh $@
-
-override_dh_auto_install:
-	dh_auto_install -- PREFIX=/usr

debian/watch

@@ -1,2 +0,0 @@
-version=3
-http://githubredir.debian.net/github/dajhorn/zfs-auto-snapshot/([\d\.].*).tar.gz

etc/zfs-auto-snapshot.cron.daily

@@ -1,2 +1,5 @@
 #!/bin/sh
-exec zfs-auto-snapshot --quiet --syslog --label=daily --keep=31 //
+
+# Only call zfs-auto-snapshot if it's available
+exec which zfs-auto-snapshot > /dev/null && \
+     zfs-auto-snapshot --quiet --syslog --label=daily --keep=31 //

etc/zfs-auto-snapshot.cron.frequent

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

etc/zfs-auto-snapshot.cron.hourly

@@ -1,2 +1,5 @@
 #!/bin/sh
-exec zfs-auto-snapshot --quiet --syslog --label=hourly --keep=24 //
+
+# Only call zfs-auto-snapshot if it's available
+exec which zfs-auto-snapshot > /dev/null && \
+     zfs-auto-snapshot --quiet --syslog --label=hourly --keep=24 //

etc/zfs-auto-snapshot.cron.monthly

@@ -1,2 +1,5 @@
 #!/bin/sh
-exec zfs-auto-snapshot --quiet --syslog --label=monthly --keep=12 //
+
+# Only call zfs-auto-snapshot if it's available
+exec which zfs-auto-snapshot > /dev/null && \
+     zfs-auto-snapshot --quiet --syslog --label=monthly --keep=12 //

etc/zfs-auto-snapshot.cron.weekly

@@ -1,2 +1,5 @@
 #!/bin/sh
-exec zfs-auto-snapshot --quiet --syslog --label=weekly --keep=8 //
+
+# Only call zfs-auto-snapshot if it's available
+exec which zfs-auto-snapshot > /dev/null && \
+     zfs-auto-snapshot --quiet --syslog --label=weekly --keep=8 //

src/zfs-auto-snapshot.sh

@@ -191,7 +191,7 @@ do_snapshots () # properties, flags, snapname, oldglob, [targets...]
 				KEEP=$(( $KEEP - 1 ))
 				if [ "$KEEP" -le '0' ]
 				then
-					if do_run "zfs destroy $FLAGS '$jj'" 
+					if do_run "zfs destroy -d $FLAGS '$jj'" 
 					then
 						DESTRUCTION_COUNT=$(( $DESTRUCTION_COUNT + 1 ))
 					else
@@ -373,7 +373,11 @@ ZFS_LIST=$(env LC_ALL=C zfs list -H -t filesystem,volume -s name \
 
 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 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) \