tsniff
asked on
flock error - no locks available.
Here is a simple test script that creates the error.
use Fcntl qw(:DEFAULT :flock);
my $file = "test.txt";
print "Content-type:text/html\n\ n";
local *FILE;
sysopen(FILE, $file, O_WRONLY | O_TRUNC | O_CREAT) or print "<p>Can't open $file: $!</p>";
flock(FILE, LOCK_EX) or print "<p>Can't flock LOCK_EX $file: $!</p>";
print FILE "Test\n";
flock(FILE, LOCK_UN) or print "<p>Can't flock LOCK_UN $file: $!</p>";
close(FILE);
print "<p>Done</p>";
It always produces the error:
Can't flock LOCK_EX test.txt: No locks available
I've never seen this before. Anyone know why and how to fix it?
use Fcntl qw(:DEFAULT :flock);
my $file = "test.txt";
print "Content-type:text/html\n\
local *FILE;
sysopen(FILE, $file, O_WRONLY | O_TRUNC | O_CREAT) or print "<p>Can't open $file: $!</p>";
flock(FILE, LOCK_EX) or print "<p>Can't flock LOCK_EX $file: $!</p>";
print FILE "Test\n";
flock(FILE, LOCK_UN) or print "<p>Can't flock LOCK_UN $file: $!</p>";
close(FILE);
print "<p>Done</p>";
It always produces the error:
Can't flock LOCK_EX test.txt: No locks available
I've never seen this before. Anyone know why and how to fix it?
ASKER CERTIFIED SOLUTION
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ASKER
I know the file is fine. It works on every server I have tested it on except one. I am trying to find a reason and solution for that one.
My best guess is that the file lives on a NFS directory.
ASKER
I believe it does.... if so, is there a way to flock over nfs?
As previously mentioned, I have seen reports of Linux kernel bugs preventing flock over NFS, so in order to fix this, your server would probably need a kernel upgrade.
As a workaround, you could use another file locking method.
As a workaround, you could use another file locking method.
Why not use a local file for a lock file?
use Fcntl qw(:DEFAULT :flock);
my $file = "test.txt";
print "Content-type:text/html\n\
local *FILE;
sysopen(FILE, $file, O_WRONLY | O_TRUNC | O_CREAT) or print "<p>Can't open $file
: $!</p>";
flock(FILE, LOCK_EX) or print "<p>Can't flock LOCK_EX $file: $!</p>";
print FILE "Test\n";
flock(FILE, LOCK_UN) or print "<p>Can't flock LOCK_UN $file: $!</p>";
close(FILE);
print "<p>Done</p>";
~
[prakasha@linuxcvs prakasha]$ perl flock.pl
Content-type:text/html
<p>Done</p>[prakasha@linux
i am not getting that message, file is proper for me.
Prakash