Just hoping to get some dev eyes on this. I'm incredibly reluctant to throw the word 'bug' around

(since 99 times out of 100, it's not -- it's almost always the config), but I can't think of any way 

that this could be a config issue, esp when the pre-2.2.34 version works as expected.

I noticed during troubleshooting that dovecot errors out if I try to create a subfolder called

'INBOX' but it'll happily create a subfolder called INBOX.SomethingElse (i.e. a folder called 

INBOX.INBOX.SomethingElse - resulting in a directory called .INBOX.SomethingElse on the 

filesystem, and leading to the problem described below). Is that sub-subfolder creation (where

the top level subfolder matches the namespace name) supposed to be allowed? It seems

odd that 'INBOX' (as a subfolder of INBOX) would be blocked but INBOX.SomethingElse (as

a subfolder of INBOX) would be allowed. I'd expect INBOX.SomethingElse (i.e. 

INBOX.INBOX.SomethingElse) would be blocked as well.

On Wed, Mar 13, 2019 at 4:46 AM Bernd Wurst via dovecot <dovecot@dovecot.org> wrote:

Hello,

we're operating dovecot on a small server. Some years ago, we migrated
from courier IMAP to dovecot. Therefore, we defined our default
Namespace "inbox" with prefix "INBOX." to have this compatible. I found
this in some migration docs those days. Generally, everything worked as
expected.

Our only namespace is configured like this:

namespace inbox {
 separator = .
  prefix = INBOX.
  inbox = yes
}

Regularly, there is no folder named INBOX or .INBOX in the file system,
I suppose this is correct.  But I found a special corner case today when
it comes to quota calculation.

When - for whatever reason - a folder .INBOX.foo (for arbitrary values
of foo) exists, the whole mailbox is counted twice in quota
recalculation. Just creating .INBOX does nothing but a subfolder
triggers the problem.

This is my shell view (replaced username and file path and deleted
unnecessary debug output)

$ cat maildirsize
268435456S
14697 17
$ maildirmake .INBOX.foo
$ sudo doveadm -D quota recalc -u <user>
[...]
doveadm(<user>): Debug: Namespace inbox: type=private, prefix=INBOX.,
sep=., inbox=yes, hidden=no, list=yes, subscriptions=yes
location=maildir:/home/.../test
doveadm(<user>): Debug: maildir++: root=/home/.../test, index=,
indexpvt=, control=, inbox=/home/.../test, alt=
doveadm(<user>): Debug: Namespace : type=private, prefix=, sep=,
inbox=no, hidden=yes, list=no, subscriptions=no location=fail::LAYOUT=none
doveadm(<user>): Debug: none: root=, index=, indexpvt=, control=,
inbox=, alt=
doveadm(<user>): Debug: quota: quota_over_flag check: quota_over_script
unset - skipping
doveadm(<user>): Debug: Quota root User quota: Recalculated relative
rules with bytes=268435456 count=0. Now grace=26843545
doveadm(<user>): Debug: Namespace INBOX.: Using permissions from
/home/.../test: mode=0700 gid=default

$ cat maildirsize
268435456S
29394 34


So the used quota has exactly been doubled by just creating an empty
subfolder.

Do you have any pointers for fixing my configuration or is this a bug in
dovecot?

I coincidentally resurrected a months-old thread with this same issue a few days ago. I'm seeing the exact same after upgrading from 2.2.32 to 2.2.36.

The original poster (who also narrowed it down to something in 2.2.34) mentioned a workaround that does indeed work, namely setting mailbox_list_index=no:

> doveadm -o 'mailbox_list_index=no' quota recalc -u myuser

I've been staring at diffs of 2.2.33 and 2.2.34 without anything jumping out at me (not a C guy, sadly). Maybe src/lib-storage/index/index-storage.c or src/lib-storage/list/mailbox-list-fs-iter.c or src/lib-storage/list/mailbox-list-index-iter.c or src/lib-storage/list/mailbox-list-index.c?

The latter few have some added strcmp's against "INBOX". Then again, there's a lot of new code in the diffs under src/lib-storage that references INBOX specifically.