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marsadm: use lamport clock for checking modification timestamps of symlinks 

- Added mars_time() function returning lamport clock
- Renamed check_mtime to check_file_aged and fixed to use mars_time()
- Renamed check_all_mtimes to check_files_modified_any_of

Commits eb849e2 1be8700 fbb415a rebased on dfeb8e6

Signed-off-by: Thomas Schoebel-Theuer <tst@1und1.de>
This commit is contained in:
Daniel Hermann 2013-04-10 18:53:07 +02:00 committed by Thomas Schoebel-Theuer
parent 7a42f95d6c
commit 3bf3745ec8
1 changed files with 45 additions and 9 deletions
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userspace/marsadm
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@ -53,6 +53,20 @@ my $ip = _get_ip() or ldie "cannot determine my IP address\n";
# timeout handling
#
# return the lamport clock time in nanosecond resolution
# fallback to system time()
#
sub mars_time {
open(my $lamport_clock, "<", "/proc/sys/mars/lamport_clock");
my $lamport_time;
while (<$lamport_clock>) {
$lamport_time = $1 if /^lamport_now=(.*)/;
}
close($lamport_clock);
return $lamport_time || time() . '0' x 9;
}
sub sleep_timeout {
if ($timeout < 0) {
sleep(5);
@ -188,23 +202,45 @@ sub check_status {
}
}
sub _check_mtime {
#
# Check if modification time of file or symlink is older than age
#
# Returns 1 if modification time is not $age seconds older than a
# reference time, either lamport clock for symlinks or system
# time for regular files. Return value 0 means "file is new enough".
#
# Returns 2 if modification time or reference time cannot be determined
#
# Note: symlinks are created/updated with lamport clock timestamps
# while normal files get timestamps from system time
#
sub _check_file_aged {
my ($path, $age) = @_;
my $mt = (lstat($path))[9];
if (!$mt) {
return 0;
my $mtime;
my $reftime; # reference time ("now")
if (-l $path) {
$mtime = (lstat($path))[9];
$reftime = int(mars_time()); # discards sub-second resolution
}
my $res = ($mt < time() - $age);
#lprint "XXX '$path' $res\n";
elsif (-f $path) {
$mtime = (stat($path))[9];
$reftime = time();
}
return 2 if (!$mtime or !$reftime); # error -> file is aged
my $res = ($mtime < $reftime - $age) ? 1 : 0;
lprint sprintf("%s: %s <=> %s ==> %s\n", $path, scalar(gmtime($mtime)), scalar(gmtime($reftime)), $res);
return $res;
}
sub _check_all_mtimes {
#
# Check if any file below $path was modified in the last $age seconds
#
sub _check_files_modified_any_of {
my ($path, $age) = @_;
my @list = glob($path);
my $res = 1;
foreach my $p (@list) {
if (!_check_mtime($p, $age)) {
if (!_check_file_aged($p, $age)) {
$res = 0;
}
}
@ -258,7 +294,7 @@ sub check_splitbrain {
_primary_res($res, "(none)", $pri, $old) unless $old eq "(none)";
_trigger();
sleep(5);
while (!_check_all_mtimes("$mars/resource-$res/{log,version,replay}-*", 60)) {
while (!_check_files_modified_any_of("$mars/resource-$res/{log,version,replay}-*", 60)) {
lprint "resource directory $res not stable, waiting....\n";
sleep_timeout();
}