[pve-devel] [PATCH v3 storage 2/3] zfspool: add blockers parameter to volume_snapshot_is_possible

Fabian Ebner f.ebner at proxmox.com
Thu Aug 12 13:01:01 CEST 2021


useful for rollback, so that only the required replication snapshots
can be removed, and it's possible to abort early without deleting any
replication snapshots if there are other non-replication snasphots
blocking rollback.

Signed-off-by: Fabian Ebner <f.ebner at proxmox.com>
---
 PVE/Storage.pm               |  4 ++--
 PVE/Storage/BTRFSPlugin.pm   |  2 +-
 PVE/Storage/Plugin.pm        |  5 ++++-
 PVE/Storage/ZFSPoolPlugin.pm | 23 +++++++++++++++++------
 4 files changed, 24 insertions(+), 10 deletions(-)

diff --git a/PVE/Storage.pm b/PVE/Storage.pm
index c04b5a2..3b3ce93 100755
--- a/PVE/Storage.pm
+++ b/PVE/Storage.pm
@@ -269,13 +269,13 @@ sub volume_resize {
 }
 
 sub volume_rollback_is_possible {
-    my ($cfg, $volid, $snap) = @_;
+    my ($cfg, $volid, $snap, $blockers) = @_;
 
     my ($storeid, $volname) = parse_volume_id($volid, 1);
     if ($storeid) {
         my $scfg = storage_config($cfg, $storeid);
         my $plugin = PVE::Storage::Plugin->lookup($scfg->{type});
-        return $plugin->volume_rollback_is_possible($scfg, $storeid, $volname, $snap);
+        return $plugin->volume_rollback_is_possible($scfg, $storeid, $volname, $snap, $blockers);
     } elsif ($volid =~ m|^(/.+)$| && -e $volid) {
         die "snapshot rollback file/device '$volid' is not possible\n";
     } else {
diff --git a/PVE/Storage/BTRFSPlugin.pm b/PVE/Storage/BTRFSPlugin.pm
index 411cab9..60fb027 100644
--- a/PVE/Storage/BTRFSPlugin.pm
+++ b/PVE/Storage/BTRFSPlugin.pm
@@ -513,7 +513,7 @@ sub volume_snapshot {
 }
 
 sub volume_rollback_is_possible {
-    my ($class, $scfg, $storeid, $volname, $snap) = @_; 
+    my ($class, $scfg, $storeid, $volname, $snap, $blockers) = @_;
 
     return 1; 
 }
diff --git a/PVE/Storage/Plugin.pm b/PVE/Storage/Plugin.pm
index b1865cb..c265e53 100644
--- a/PVE/Storage/Plugin.pm
+++ b/PVE/Storage/Plugin.pm
@@ -900,8 +900,11 @@ sub volume_snapshot {
     return undef;
 }
 
+# Asserts that a rollback to $snap on $volname is possible.
+# If certain snapshots are preventing the rollback and $blockers is an array
+# reference, the snapshot names can be pushed onto $blockers prior to dying.
 sub volume_rollback_is_possible {
-    my ($class, $scfg, $storeid, $volname, $snap) = @_;
+    my ($class, $scfg, $storeid, $volname, $snap, $blockers) = @_;
 
     return 1;
 }
diff --git a/PVE/Storage/ZFSPoolPlugin.pm b/PVE/Storage/ZFSPoolPlugin.pm
index c2a0385..8d79f38 100644
--- a/PVE/Storage/ZFSPoolPlugin.pm
+++ b/PVE/Storage/ZFSPoolPlugin.pm
@@ -480,18 +480,29 @@ sub volume_snapshot_rollback {
 }
 
 sub volume_rollback_is_possible {
-    my ($class, $scfg, $storeid, $volname, $snap) = @_;
+    my ($class, $scfg, $storeid, $volname, $snap, $blockers) = @_;
 
     # can't use '-S creation', because zfs list won't reverse the order when the
     # creation time is the same second, breaking at least our tests.
     my $snapshots = $class->zfs_get_sorted_snapshot_list($scfg, $volname, ['-s', 'creation']);
-    my $recentsnap = $snapshots->[-1];
 
-    die "can't rollback, no snapshots exist at all\n"
-	if !defined($recentsnap);
+    my $found;
+    $blockers //= []; # not guaranteed to be set by caller
+    for my $snapshot ($snapshots->@*) {
+	if ($snapshot eq $snap) {
+	    $found = 1;
+	} elsif ($found) {
+	    push $blockers->@*, $snapshot;
+	}
+    }
+
+    my $volid = "${storeid}:${volname}";
+
+    die "can't rollback, snapshot '$snap' does not exist on '$volid'\n"
+	if !$found;
 
-    die "can't rollback, '$snap' is not most recent snapshot\n"
-	if $snap ne $recentsnap;
+    die "can't rollback, '$snap' is not most recent snapshot on '$volid'\n"
+	if scalar($blockers->@*) > 0;
 
     return 1;
 }
-- 
2.30.2





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