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[mv] Flock Locking over NFS
****** message to minivend-users from "Kevin Walsh" <kevin@cursor-software.co.uk> ******
MiniVend currently uses flock to lock its files but flock is not
supported on Linux when locking files over NFS.
The following patch adds a fcntl locking mechanism that is
supported on Linux/NFS. Perhaps someone other than us will find
it useful when setting up a MiniVend farm with a shared session
database.
The patch is for lib/Vend/Util.pm (MV 4.04).
-------------------CUT HERE-----------------------------
908a909,944
> ### fcntl locking
>
> sub fcntl_lock {
> my ($fh, $excl, $wait) = @_;
> my $flag = $excl ? F_WRLCK : F_RDLCK;
> my $buf = pack("ssLL",$flag,0,0,0);
>
> LOCKLOOP:{
> if ($wait) {
> if (! fcntl($fh, F_SETLKW, $buf)) {
> redo LOCKLOOP if $! =~ m/^Interrupted/;
> die "Could not lock file: $!\n";
> }
> }
> else {
> if (! fcntl($fh, F_SETLK, $buf)) {
> redo LOCKLOOP if $! =~ m/^Interrupted/;
> if ($! =~ m/^Try again/
> or $! =~ m/^Resource temporarily unavailable/
> or $! =~ m/^Operation would block/) {
> return 0;
> }
> die "Could not lock file: $!\n";
> }
> }
> return 1;
> }
> }
>
> sub fcntl_unlock {
> my ($fh) = @_;
> my $buf = pack("ssLL",F_WRLCK,0,0,0);
> fcntl($fh, F_UNLCK, $buf) or die "Could not unlock file: $!\n";
> }
>
>
917c953
< $use = 'flock';
---
> $use = 'fcntl';
926a963,966
> }
> elsif ($use eq 'fcntl') {
> $lock_function = \&fcntl_lock;
> $unlock_function = \&fcntl_unlock;
-------------------CUT HERE-----------------------------
Have the appropriate amount of fun :-)
--
_/ _/ _/_/_/_/ _/ _/ _/_/_/ _/ _/
_/_/_/ _/_/ _/ _/ _/ _/_/ _/ K e v i n W a l s h
_/ _/ _/ _/ _/ _/ _/ _/_/ kevin@cursor-software.co.uk
_/ _/ _/_/_/_/ _/ _/_/_/ _/ _/
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