Merge pull request #175 from phreaker0/dst-fixes

DST fixes

sanoid

@@ -334,6 +334,19 @@ sub take_snapshots {
 
 	my @newsnaps;
 
+	# get utc timestamp of the current day for DST check
+	my $daystartUtc = timelocal(0, 0, 0, $datestamp{'mday'}, ($datestamp{'mon'}-1), $datestamp{'year'});
+	my ($isdst) = (localtime($daystartUtc))[8];
+	my $dstOffset = 0;
+
+	if ($isdst ne $datestamp{'isdst'}) {
+		# current dst is different then at the beginning og the day
+		if ($isdst) {
+			# DST ended in the current day
+			$dstOffset = 60*60;
+		}
+	}
+
 	if ($args{'verbose'}) { print "INFO: taking snapshots...\n"; }
 	foreach my $section (keys %config) {
 		if ($section =~ /^template/) { next; }
@@ -357,6 +370,9 @@ sub take_snapshots {
 				my @preferredtime;
 				my $lastpreferred;
 
+				# to avoid duplicates with DST
+				my $dateSuffix = "";
+
 				if ($type eq 'hourly')     {
 					push @preferredtime,0; # try to hit 0 seconds
 					push @preferredtime,$config{$section}{'hourly_min'};
@@ -365,6 +381,13 @@ sub take_snapshots {
 					push @preferredtime,($datestamp{'mon'}-1); # january is month 0
 					push @preferredtime,$datestamp{'year'};
 					$lastpreferred = timelocal(@preferredtime);
+
+					if ($dstOffset ne 0) {
+						# timelocal doesn't take DST into account
+						$lastpreferred += $dstOffset;
+						# DST ended, avoid duplicates
+						$dateSuffix = "_y";
+					}
 					if ($lastpreferred > time()) { $lastpreferred -= 60*60; } # preferred time is later this hour - so look at last hour's
 				} elsif ($type eq 'daily')   {
 					push @preferredtime,0; # try to hit 0 seconds
@@ -374,7 +397,29 @@ sub take_snapshots {
 					push @preferredtime,($datestamp{'mon'}-1); # january is month 0
 					push @preferredtime,$datestamp{'year'};
 					$lastpreferred = timelocal(@preferredtime);
-					if ($lastpreferred > time()) { $lastpreferred -= 60*60*24; } # preferred time is later today - so look at yesterday's
+
+					# timelocal doesn't take DST into account
+					$lastpreferred += $dstOffset;
+
+					# check if the planned time has different DST flag than the current
+					my ($isdst) = (localtime($lastpreferred))[8];
+					if ($isdst ne $datestamp{'isdst'}) {
+						if (!$isdst) {
+							# correct DST difference
+							$lastpreferred -= 60*60;
+						}
+					}
+
+					if ($lastpreferred > time()) {
+						$lastpreferred -= 60*60*24;
+
+						if ($dstOffset ne 0) {
+							# because we are going back one day
+							# the DST difference has to be accounted
+							# for in reverse now
+							$lastpreferred -= 2*$dstOffset;
+						}
+					} # preferred time is later today - so look at yesterday's
 				} elsif ($type eq 'monthly') {
 					push @preferredtime,0; # try to hit 0 seconds
 					push @preferredtime,$config{$section}{'monthly_min'};
@@ -402,7 +447,7 @@ sub take_snapshots {
 					# update to most current possible datestamp
 					%datestamp = get_date();
 					# print "we should have had a $type snapshot of $path $maxage seconds ago; most recent is $newestage seconds old.\n";
-					push(@newsnaps, "$path\@autosnap_$datestamp{'sortable'}_$type");
+					push(@newsnaps, "$path\@autosnap_$datestamp{'sortable'}${dateSuffix}_$type");
 				}
 			}
 		}

tests/2_dst_handling/run.sh

@@ -0,0 +1,54 @@
+#!/bin/bash
+set -x
+
+# this test will check the behaviour arround a date where DST ends
+# with hourly, daily and monthly snapshots checked in a 15 minute interval
+
+# Daylight saving time 2017 in Europe/Vienna began at 02:00 on Sunday, 26 March
+# and ended at 03:00 on Sunday, 29 October. All times are in
+# Central European Time.
+
+. ../common/lib.sh
+
+POOL_NAME="sanoid-test-2"
+POOL_TARGET=""  # root
+RESULT="/tmp/sanoid_test_result"
+RESULT_CHECKSUM="a916d9cd46f4b80f285d069f3497d02671bbb1bfd12b43ef93531cbdaf89d55c"
+
+# UTC timestamp of start and end
+START="1509141600"
+END="1509400800"
+
+# prepare
+setup
+checkEnvironment
+disableTimeSync
+
+# set timezone
+ln -sf /usr/share/zoneinfo/Europe/Vienna /etc/localtime
+
+timestamp=$START
+
+mkdir -p "${POOL_TARGET}"
+truncate -s 512M "${POOL_TARGET}"/zpool2.img
+
+zpool create -f "${POOL_NAME}" "${POOL_TARGET}"/zpool2.img
+
+function cleanUp {
+  zpool export "${POOL_NAME}"
+}
+
+# export pool in any case
+trap cleanUp EXIT
+
+while [ $timestamp -le $END ]; do
+    date --utc --set @$timestamp; date; "${SANOID}" --cron --verbose
+    timestamp=$((timestamp+900))
+done
+
+saveSnapshotList "${POOL_NAME}" "${RESULT}"
+
+# hourly daily monthly
+verifySnapshotList "${RESULT}" 73 3 1 "${RESULT_CHECKSUM}"
+
+# one more hour because of DST

tests/2_dst_handling/sanoid.conf

@@ -0,0 +1,10 @@
+[sanoid-test-2]
+	use_template = production
+
+[template_production]
+	hourly = 36
+	daily = 30
+	monthly = 3
+	yearly = 0
+	autosnap = yes
+	autoprune = no