my $f = "$inline_dir/.public-inbox.lock";
open my $fh, '>', $f or die "failed to open $f: $!\n";
flock($fh, LOCK_EX) or die "LOCK_EX failed on $f: $!\n";
my $f = "$inline_dir/.public-inbox.lock";
open my $fh, '>', $f or die "failed to open $f: $!\n";
flock($fh, LOCK_EX) or die "LOCK_EX failed on $f: $!\n";