Ongoing inaccessible mailbox woes

[Patrick Goetz]

When I upgraded from 2.4.17 to 2.5.3, I had one user who experienced 
inaccessible mail folders post upgrade.  Running reconstruct:

    # systemctl stop cyrus-master
    # su - cyrus
    # /usr/lib/cyrus/bin/reconstruct -r -f user/djones
    # <Ctrl>-d
    # systemctl start cyrus-master

temporarily resolved the problem, but then it came back, so I thought 
this might be a 2.5.3 bug.  I just upgraded to 2.5.7, and the problem 
persists.  Furthermore, running reconstruct no longer brings the mail 
messages back and I get the following error messages during the 
reconstruction on precisely the folders which are not accessible:

----------------------------------------------------
user/djones/World Mission Conference
user/djones/World Mission Conference/2008
user/djones/World Mission Conference/2011
createmailbox user.djones.Archives Staff.Keely Davis: Mailbox already exists
createmailbox user.djones.Archives Staff.Lauren Kelsey: Mailbox already 
exists
createmailbox user.djones.Archives Staff.Stacey Williams: Mailbox 
already exists
createmailbox user.djones.Archives Staff.Drew Smith: Mailbox already exists
createmailbox user.djones.Archives Staff.Whitney: Mailbox already exists
createmailbox user.djones.Archives Staff.Delia Alexander: Mailbox 
already exists
createmailbox user.djones.Archives Staff.Whitney Howell: Mailbox already 
exists
createmailbox user.djones.Archives Staff.Former Staff: Mailbox already 
exists
createmailbox user.djones.Archives Staff.Julia Miller: Mailbox already 
exists
createmailbox user.djones.Archives Staff.Weekly Reports: Mailbox already 
exists
createmailbox user.djones.Archives Staff.Eleanor Meuller: Mailbox 
already exists
createmailbox user.djones.Archives Staff.Corrine Smith.Inquiries: 
Mailbox already exists
createmailbox user.djones.Archives Staff.Corrine Smith.Destruction: 
Mailbox already exists
createmailbox user.djones.Archives Staff.Corrine Smith.SharePoint: 
Mailbox already exists
----------------------------------------------------

The folders and files in the filesystem look completely ordinary and 
have the correct permissions.  However, under user/djones, this user has 
the following mail folders:

drwx------  18 cyrus mail   98304 Dec  7 11:11 Archives Staff
drwx------   5 cyrus mail    4096 Oct  3 05:21 Archives Staff Retreat


Now I'm starting to wonder if there isn't some kind of folder name 
length bug at work here (maybe just in reconstruct?) so that the mail 
folders

   Archives Staff
   Archives Staff Retreat

are being seen by reconstruct as the same folder?

I'm kind of grasping at straws here, unfortunately.  Last time this 
happened, Bron suggested that I needed to set up logging with debugging 
turned on.  If this is the only way to get to the bottom of this, I 
guess I'll have to do that.  (Since the mail server is a systemd system, 
traditional syslog logging is not turned on by defaul and will require 
some effort to enable.)