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marsadm: workaround concept bug in _get_actual_primary(), deprecate it 

The conceptual bug was leading to systematic false-positive failures in the
old test_suite. These failures were depeding on the _names_ of the
involved hosts: just run it on a pair of differently named hosts
following different naming conventions, and 50 out of 90 testcases
were failing false-positively.
This commit is contained in:
Thomas Schoebel-Theuer 2014-10-02 10:23:43 +02:00 committed by Thomas Schoebel-Theuer
parent 743e81a541
commit 1b4805464a
1 changed files with 16 additions and 0 deletions
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@ -920,11 +920,26 @@ sub get_size {
return $arg; return $arg;
} }
# DEPRECATED
#
# TST NOTE: avoid calling this function. As such it is conceptually wrong,
# because during split-brain situations, there exists a _set_ of non-unique
# primaries. I want to remove this function, but I currently can't because
# other internal software at 1&1 is depending on it.
# #
# Get actual primary node from links below actual-*/ subdirs # Get actual primary node from links below actual-*/ subdirs
# #
sub _get_actual_primary { sub _get_actual_primary {
my ($res) = @_; my ($res) = @_;
# TST: Presence of local device takes precedence over anything else.
# This tries to workaround the most important special case of
# split-brain situations, but cannot fix the problem exhaustively.
llog "DEPRECATED: you are trying to uniquely identify an actual primary hostname (as seen from host $host resource $res), but this is conceptually wrong because in split-brain situations there may exist multiple ones. Use view-is-primary instead. That would be safe.\n";
my $name = get_link("$mars/resource-$res/device-$real_host", 1);
my $dev = "/dev/mars/$name";
return $real_host if -b $dev;
# The following old code is CONCEPTUALLY WRONG for split-brain situations (see NOTE above)
my @primary_links = glob("$mars/resource-$res/actual-*/is-primary"); my @primary_links = glob("$mars/resource-$res/actual-*/is-primary");
my $primary; my $primary;
foreach my $link (@primary_links) { foreach my $link (@primary_links) {
@ -2484,6 +2499,7 @@ sub eval_fn {
my $op = $1; my $op = $1;
my $primary; my $primary;
if ($op eq "actual") { if ($op eq "actual") {
lwarn "DEPRECATED: you are trying to uniquely identify an actual primary hostname, but this is conceptually wrong because in split-brain situations there may exist multiple ones. Use view-is-primary instead. That would be safe.\n";
$primary = _get_actual_primary($$env{"res"}); $primary = _get_actual_primary($$env{"res"});
} else { } else {
$primary = _get_designated_primary($$env{"res"}); $primary = _get_designated_primary($$env{"res"});