locking problems with 2.1.9

[pete at wookie.oit.umass.edu]

We are experiencing locking problems with cyrus 2.1.9 on a Solaris 8
system using fcntl and skiplist (except flat for subscriptions).
We've seen the following issues:

  * Lmtpd's acquire a lock on a cyrus.seen file and never get it;
    they stack up as mail comes in.
  * In syslog we see 'IOERROR: reading message: unexpected end of file'
  * In various partition's 'stage.' directory we see hundreds of 
    messages stacked up waiting for - surprise - users who seem to
    be having the locking issues.
  * Some users have cyrus.seen.NEW lying around in their folders.

The above problems exist for only a handful of users; the other 12k
users seem to be user'ing along without difficulty.  But when the
other 18k users move to this box it might get worse...

All users were transferred from a different Solaris system (cyrus
1.5.27)  to this new one using rsync (mail/folder dirs, quota,
subscriptions).

Any pointers or suggestions would be helpful!