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marsadm: fix recursion depth of _get_common_ancestor()

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Thomas Schoebel-Theuer 2014-03-06 21:12:26 +01:00
parent 0d5349b2ca
commit 1715b4fd40
1 changed files with 40 additions and 37 deletions
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userspace/marsadm
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@ -581,46 +581,49 @@ sub _get_prev_pos {
}
sub _get_common_ancestor {
# TODO: recursive formulation, improve efficiency
my ($basedir, $pos1, $host1, $dep1, $pos2, $host2, $dep2) = @_;
my ($p1, $nr1, $from1, $len1) = _parse_pos($pos1, 0);
my ($p2, $nr2, $from2, $len2) = _parse_pos($pos2, 0);
if ($p1 eq $p2) {
# usually no split brain here (only if both path depths are non-zero)
my $split = ($dep1 && $dep2);
if (!$split) { # additionally check the corresponding version links
my $path1 = sprintf("$basedir/version-%09d-$from1", $nr1);
my $path2 = sprintf("$basedir/version-%09d-$from2", $nr2);
if (my $vers1 = get_link($path1) and my $vers2 = get_link($path2)) {
$split = 1 if $vers1 ne $vers2;
for (;;) {
my ($basedir, $pos1, $host1, $dep1, $pos2, $host2, $dep2) = @_;
my ($p1, $nr1, $from1, $len1) = _parse_pos($pos1, 0);
my ($p2, $nr2, $from2, $len2) = _parse_pos($pos2, 0);
if ($p1 eq $p2) {
# usually no split brain here (only if both path depths are non-zero)
my $split = ($dep1 && $dep2);
if (!$split) { # additionally check the corresponding version links
my $path1 = sprintf("$basedir/version-%09d-$from1", $nr1);
my $path2 = sprintf("$basedir/version-%09d-$from2", $nr2);
if (my $vers1 = get_link($path1) and my $vers2 = get_link($path2)) {
$split = 1 if $vers1 ne $vers2;
}
}
return ($p1, $split);
} elsif ($nr1 > $nr2) {
# just flip arguments
@_ = ($basedir, $pos2, $host2, $dep2, $pos1, $host1, $dep1);
next;
} elsif ($nr1 < $nr2) {
# recursively advance path depth
my $vers2 = _get_prev_pos($basedir, $nr2, $host2);
return ("", -1) if !$vers2;
@_ = ($basedir, $pos1, $host1, $dep1, $vers2, $host2, $dep2 + 1);
next;
} elsif ($from1 ne $from2) {
# split brain is sure now, but continue computing the common split point
my $vers1 = _get_prev_pos($basedir, $nr1, $host1);
return ("", 1) if !$vers1;
my $vers2 = _get_prev_pos($basedir, $nr2, $host2);
return ("", 1) if !$vers2;
my ($res, $split) = _get_common_ancestor($basedir, $vers1, $host1, $dep1 + 1, $vers2, $host2, $dep2 + 1);
return ($res, 1);
} elsif ($len1 < $len2) {
# there may be no split brain (just incomplete replay) depending on path depth
return ($p1, $dep1);
} elsif ($len2 < $len1) {
# dto symmetric
return ($p2, $dep2);
}
return ($p1, $split);
} elsif ($nr1 > $nr2) {
# just flip arguments
return _get_common_ancestor($basedir, $pos2, $host2, $dep2, $pos1, $host1, $dep1);
} elsif ($nr1 < $nr2) {
# recursively advance path depth
my $vers2 = _get_prev_pos($basedir, $nr2, $host2);
return ("", -1) if !$vers2;
return _get_common_ancestor($basedir, $pos1, $host1, $dep1, $vers2, $host2, $dep2 + 1);
} elsif ($from1 ne $from2) {
# split brain is sure now, but continue computing the common split point
my $vers1 = _get_prev_pos($basedir, $nr1, $host1);
return ("", 1) if !$vers1;
my $vers2 = _get_prev_pos($basedir, $nr2, $host2);
return ("", 1) if !$vers2;
my ($res, $split) = _get_common_ancestor($basedir, $vers1, $host1, $dep1 + 1, $vers2, $host2, $dep2 + 1);
return ($res, 1);
} elsif ($len1 < $len2) {
# there may be no split brain (just incomplete replay) depending on path depth
return ($p1, $dep1);
} elsif ($len2 < $len1) {
# dto symmetric
return ($p2, $dep2);
lwarn "error in algorithm: $p1, $nr1, $from1, $len1 : $p2, $nr2, $from2, $len2\n";
return ("", -1);
}
lwarn "error in algorithm: $p1, $nr1, $from1, $len1 : $p2, $nr2, $from2, $len2\n";
return ("", -1);
}
sub get_common_ancestor {