ext4, fsync(2), and perl

[Christopher Chan]

On Friday, March 05, 2010 04:13 PM, Josef Wolf wrote:
> On Fri, Mar 05, 2010 at 10:37:04AM +0800, Christopher Chan wrote:
>> On Friday, March 05, 2010 03:19 AM, Josef Wolf wrote:
>
> Thanks for your response, Christopher!
>
> [ ... ]
>>>      # but for the directory, I have to comment the sync operations to
>>>      # avoid an "illegal filehandle" error
>>>      #
>>>      my $hd = new IO::Handle;
>>>      opendir ($hd, $histdir) or die "open $histdir: $!";
>>>      link ($history, "$history-$ymd_hms") unless -e "$history-$ymd_hms";
>>> #   $hd->sync or die "sync $histdir: $!";
>>>      rename "$history.$$", $history or die "Cant rename: $!";
>>> #   $hd->sync&&   $hd->closedir or die "closedir $histdir: $!";
>>>
>>> Any ideas how to properly fsync the directory in perl?
>>
>>     my $hd;
>>     open($hd, $histdir);
>>     link ($history, "$history-$ymd_hms") unless -e "$history-$ymd_hms";
>>     rename "$history.$$", $history or die "Cant rename: $!";
>>     unless (fsync($hd)) {
>>       print STDERR "error: problem fsync-ing directory '$histdir': $!\n";
>>       close($dh);
>>       return 0;
>>     }
>>
>> Try this?
>
> This tells me I have to use IO::Handle::sync() instead. The POSIX manpage
> states that fsync is deprecated. This is why I used IO::Handle in my original
> example.

IO::Handle is for files only? I doubt that it will work with directories.

POSIX manpage says fsync is deprecated? That is highly impossible...not 
if they want just about every program rewritten.


>
> And when I try to use IO::Handle::sync on a directory opened with open()
> like this
>
>    my $hd = new IO::Handle;
>    open ($hd, $dir) or die "open $dir: $!";
>    $hd->sync or die "sync $dir: $!";
>    $hd->close or die "close $dir: $!";
>
> I get this error:
>
>    sync /home/jw: Invalid argument at ./t.pl line 12.
>
> I guess the problem is that the directory is opened in read-only mode. But
> OTOH, the kernel will (hopefully) not let me open it in any other mode.
>

IO::Handle is for files only I believe...