[Samba] secrets.tdb locking fun!

[Mac]

Hi all,

	After much grief today, we'd like to support the 'TODO' note in
source/lib/util_tdb.c  :-

/* TODO: If we time out waiting for a lock, it might
 * be nice to use F_GETLK to get the pid of the
 * process currently holding the lock and print that
 * as part of the debugging message. -- mbp */


It could have saved us a whole-sale restart of Samba if we could have
more easily identified the process that was causing us to get loads and
loads of:-

[2007/06/15 13:02:20, 0, pid=5430] tdb/tdbutil.c:tdb_log(783)
  tdb(/usr/local/samba/private/secrets.tdb): tdb_lock failed on list 2 ltype=2 (Interrupted system call)
[2007/06/15 13:02:20, 0, pid=5430] tdb/tdbutil.c:tdb_chainlock_with_timeout_internal(82)
  tdb_chainlock_with_timeout_internal: alarm (10) timed out for key replay cache mutex in tdb /usr/local/samba/private/secrets.tdb


We believe we did find it, but only by sending a SIGTERM to all 'smbd'
processes and being left with 'smbd' proceses that didn't die.  (SIGKILL
did remove them).


                               Mac
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