[Dovecot] dovecot 2.2.0 corrupts mailboxes?

[Emmanuel Dreyfus]

Hi

On april 17th, I upgraded from dovecot 2.1.13 to 2.2.0. Since that time,
I had two different users that reported received three incident of
messages that disapeared from their mailboxes. 

The mailbox format is mbox on local FFS filesystem (no NFS), and I use
filesystem quotas (but both users are far from filling their quotas).
When the message disapeared, it was always a whole rand of dates. On the
last incident reported, the user also saw some message being duplicated
many times. 

There is something interesting in the logs:

May  4 20:16:30 volanges dovecot: imap(jdoe): Error: Cached message size
smaller than expected (2000 < 8063)
May  4 20:16:30 volanges dovecot: imap(jdoe): Error: Corrupted index
cache file /mail/indexes/jdoe/.imap/INBOX/dovecot.index.cache: Broken
physical size for mail UID 141869
May  4 20:19:48 volanges dovecot: imap(jdoe): Error: Cached message size
smaller than expected (9711 < 16248)
May  4 20:19:48 volanges dovecot: imap(jdoe): Error: Corrupted index
cache file /mail/indexes/jdoe/mail/.imap/Arxiv/dovecot.index.cache:
Broken physical size for mail UID 4383
May  4 21:14:35 volanges dovecot: imap(jdoe): Error: Cached message size
smaller than expected (1878 < 8066)
May  4 21:14:35 volanges dovecot: imap(jdoe): Error: Corrupted index
cache file /mail/indexes/jdoe/mail/.imap/CNRS/dovecot.index.cache:
Broken physical size for mail UID 290
May  4 21:15:17 volanges dovecot: imap(jdoe): Error: Cached message size
smaller than expected (17285 < 24440)
May  4 21:15:17 volanges dovecot: imap(jdoe): Error: Corrupted index
cache file /mail/indexes/jdoe/mail/.imap/Commandes/dovecot.index.cache:
Broken physical size for mail UID 680

Does that ring a bell? I am tempted to downgrade to 2.1.13. Does it
makes sense? Is it safe to do so?

-- 
Emmanuel Dreyfus
http://hcpnet.free.fr/pubz
manu at netbsd.org