[Mailman-Users] flock problems

[Brad Crittenden]

i started digging around to try to figure this out and discovered the
flock.py class that is distributed with mailman.  i see that several
classes use this flock class for their locking but MailList uses the
lock method on a posixfile object, which in turn calls fcntl.

the flock.py description claims that it works across platforms and with
NFS.  i modified MailList.py to use flock instead of posixfile locking
and it *appears* to work.

can anyone comment on this approach?  is there some reason why MailList
does not use flock?

thanks,

brad


> occasionally i get flock problems that manifest themselves as follows:
>
>    ----- Transcript of session follows -----
> Traceback (innermost last):
>   File "/home/mailman/scripts/post", line 45, in ?
>     mlist = MailList.MailList(sys.argv[1])
>   File "/home/mailman/Mailman/MailList.py", line 60, in __init__
>     self.Load()
>   File "/home/mailman/Mailman/MailList.py", line 767, in Load
>     self.Lock()
>   File "/home/mailman/Mailman/MailList.py", line 1340, in Lock
>     self._lock_file.lock('w|', 1)
>   File "/usr/lib/python1.5/posixfile.py", line 192, in lock
>     flock = fcntl.fcntl(self._file_.fileno(), cmd, flock)
> IOError: [Errno 37] No locks available
> 554 "|/home/mailman/mail/wrapper post test"... unknown mailer error 1
>
> -----------
>
> the mail server is running on a RedHat 6.0 box NFS mounting home
> directories, including /home/mailman where the locks live.
> the web server
> is running on a solaris box which exports the home directories.
>
> this problem showed up about six weeks ago and then just as
> mysteriously
> went away.  it worked flawlessly from the mail server side
> and the web side
> until this morning.
>
> has anyone seen this before?  suggestions?
>
> thanks,
>
> brad