[Dovecot] too many open files error when using quota plugin

[Justin McAleer]

With the quota plugin loaded (even with a quota value of 0), I get 
errors like the following:

open(/var/mailstore/01/1a/301620/Maildir/cur/1169654988.P22440Q0M696852.<hostname 
stripped>,S=4437552:2,Sbc) failed: Too many open files

To do this, I have a folder with about 700 messages and I tell 
Thunderbird to run junkmail controls on it (fetches all messages). 
Watching an strace on the imap process I'm connected to, the problem 
seems to be when the plugin goes to close the maildirsize file, it's not 
closing the correct file descriptor:

open("/var/mailstore/01/1a/301620/Maildir/./maildirsize", 
O_RDWR|O_APPEND) = 1016
 read(1016, "1024S\n395 1\n397 1\n", 5120) = 18
 read(1016, "", 5102)                    = 0
 close(4294967295)                       = -1 EBADF (Bad file descriptor)

It closes that same descriptor every time.

On a side note, I'm just curious why it needs to read the maildirsize 
file for a fetch request anyway?