betterworld has asked for the wisdom of the Perl Monks concerning the following question:
Hi,
according to the Linux man page of fsync(2):
Calling fsync() does not necessarily ensure that the entry in the directory containing the file has also reached disk. For that an explicit fsync() on a file descriptor for the directory is also needed.
So, how do we fsync directories in Perl? perldoc POSIX says that fsync() should be done with the sync method in IO::Handle. So I tried this with a directory:
use IO::Handle; open my $f, '/tmp' or die $!; $f->sync or die "fsync: $!\n";
This bails out with "fsync: Invalid argument". According to strace, no fsync syscall is even tried.
I tried opendir too:
use IO::Handle; my $f = IO::Handle->new; opendir $f, '/tmp' or die $!; $f->sync or die "fsync: $!\n";
with the same result.
On the other hand, an equivalent C program succeeds and properly calls fsync according to strace:
#include <unistd.h> #include <stdlib.h> #include <stdio.h> #include <fcntl.h> #include <sys/types.h> #include <sys/stat.h> int main (void) { int fd = open("/tmp", 0); if (fd < 0) { perror("open: /tmp"); exit(1); } if (fsync(fd) < 0) { perror("fsync: /tmp"); exit(1); } return 0; }
My question: What is the proper way to do fsync with directories in Perl? Or is this just a bug in IO::Handle?
(All tests have been done on a current Debian Squeeze (testing) with perl 5.10.1-12.)
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Replies are listed 'Best First'. | |
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Re: fsyncing directories
by salva (Canon) on Apr 27, 2010 at 12:18 UTC | |
by betterworld (Curate) on Apr 27, 2010 at 13:26 UTC | |
Re: fsyncing directories
by ikegami (Patriarch) on Apr 27, 2010 at 12:51 UTC | |
Re: fsyncing directories
by Anonymous Monk on Apr 27, 2010 at 11:33 UTC | |
by betterworld (Curate) on Apr 27, 2010 at 12:09 UTC | |
Re: fsyncing directories
by JavaFan (Canon) on Apr 27, 2010 at 12:38 UTC | |
Re: fsyncing directories
by ig (Vicar) on Apr 27, 2010 at 17:07 UTC | |
by betterworld (Curate) on Apr 27, 2010 at 18:42 UTC | |
by ig (Vicar) on Apr 27, 2010 at 20:20 UTC |
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