do rotation only, if maximum previous level exists [patch]

[Marwe]

I created a feature request a whila ago on
http://sourceforge.net/p/rsnapshot/feature-requests/30/

Since sourceforge seems to be dead or at least taken over by criminals [1], I repeat it here and add the patch file.
Hi,
here I have a simple patch that prevents rotation in a level, if there is nothing to roll into it from the lower level (e.g. no daily.{max} -> do not rotate weekly to prevent disappearing weekly.0).
Until now rotation is always done, and leads to holes in the backup scheme (e.g. weekly.[013] exist,weekly.[2] missing due to forced rotation).
This can then later lead to holes in the next levels (e.g. monthly.0 missing, if weekly.3 missing during monthly rotation), too.

I regard this as bug and the attached patch is quite simple.
Somebody should check and decide,
a) if there should be an option for the old behaviour (the 'dumb'/forced rotate).
b) if there are any problems with just bailing out then (I dont think so, but there are some options checked in the following parts).

Thanks for looking into it,
Martin

[1] http://www.gluster.org/2013/08/how-far-the-once-mighty-sourceforge-has-fallen/

[Marwe]

Hm, I don't know where to add a patch file, git just works via forks I guess.
Whatever, patch is on sourceforge (see link above), a patch against a more recent git version pasted here:

diff --git a/rsnapshot-program.pl b/rsnapshot-program.pl
index 5fea412..b8e5d81 100755
--- a/rsnapshot-program.pl
+++ b/rsnapshot-program.pl
@@ -4226,7 +4226,15 @@ sub rotate_higher_interval {
    my $interval_max        = $$id_ref{'interval_max'};
    my $prev_interval       = $$id_ref{'prev_interval'};
    my $prev_interval_max   = $$id_ref{'prev_interval_max'};
-   
+
+   # here we check, if $prev_interval.$prev_interval_max exists and only do the rotation, if from that level can be pulled...
+   # otherwise bail. Maybe there should be an option for such new behaviour, too?
+   if (! -d "$config_vars{'snapshot_root'}/$prev_interval.$prev_interval_max" ) {
+       print_err ("Did not find previous interval max ($config_vars{'snapshot_root'}/$prev_interval.$prev_interval_max), refusing to rotate this level ($interval)", 1);
+       syslog_err("Did not find previous interval max ($config_vars{'snapshot_root'}/$prev_interval.$prev_interval_max), refusing to rotate this level ($interval)");
+       bail();
+   }
+
    # ROTATE DIRECTORIES
    #
    # delete the oldest one (if we're keeping more than one)

[myrdd]

Thanks for your patch! I've created a pull request (#34). There I've added some code to the rotate_lowest_snapshots() subroutine, which prevents rotation of the highest interval if sync_first is enabled but the .sync directory doesn't exist.

[nkadel-skyhook]

Looks like the code got merged. Close this one?

[Marwe]

Thanks for the great work, further discussions, additions and merges. closing.