dovecot - Jan 2010 - Dovecot Quota Problem

I'm using Dovecot LDA with Exim.  I'm also using Dictionary Quotas in a
MySQL database.  I want to avoid backscatter completely, so I set
"quota_full_tempfail = yes" and handle quota checking in the Exim RCPT
ACL
during the SMTP session.  The problem lies in the case where a user's
account is nearly full.  Smaller messages will continue to come through,
but a larger message would get queued for retry since it will push the
account over quota.  I need Dovecot's quota to exhibit the same behavior as
Exim's "quota_is_inclusive=false".
>From Exim docs:
quota_is_inclusive=false
When this is done, the check for exceeding the quota does not include the
current message. Thus, deliveries continue until the quota has been
exceeded; thereafter, no futher messages are delivered.


Any ideas on how I can implement this inside of Dovecot?

Thanks,
-Ken Price

On Tue, 05 Jan 2010 11:59:45 -0500, Ken Price <lists at nettwrek.com>
wrote:
> I'm using Dovecot LDA with Exim.  I'm also using Dictionary Quotas
in a
> MySQL database.  I want to avoid backscatter completely, so I set
> "quota_full_tempfail = yes" and handle quota checking in the Exim
RCPT
ACL
> during the SMTP session.  The problem lies in the case where a user's
> account is nearly full.  Smaller messages will continue to come through,
> but a larger message would get queued for retry since it will push the
> account over quota.  I need Dovecot's quota to exhibit the same
behavior
as
> Exim's "quota_is_inclusive=false".
> 
>>From Exim docs:
> quota_is_inclusive=false
> When this is done, the check for exceeding the quota does not include
the
> current message. Thus, deliveries continue until the quota has been
> exceeded; thereafter, no futher messages are delivered.
> 
> 
> Any ideas on how I can implement this inside of Dovecot?
Ok, since I've received no responses on my original post, I went about
digging through the source.  I *think* I found the line which I need to
change in order to check the available quota, but not include the current
message size in the calculation.  My C++ is rusty to say the least, and I'm
having a bit of trouble understanding some of the functions, so any help
will be appreciated.  This is part of the "quota_default_test_alloc()"
function.  Ideally the patch would add the ability to enable/disable this
capability in the dovecot config file, but I'm just looking for a quick
'n'
dirty hack at the moment.

--------------
dovecot-1.2.9/src/plugins/quota/quota.c
@@ -969,4 +969,4 @@
	*too_large_r = FALSE;

-       if (ctx->count_left != 0 && ctx->bytes_left >=
ctx->bytes_used +
size)
+       if (ctx->count_left != 0 && ctx->bytes_left > 0)
		return 1;
--------------

Any help would be appreciated!

Thanks,
Ken

On 5.1.2010, at 18.59, Ken Price wrote:
> I'm using Dovecot LDA with Exim.  I'm also using Dictionary Quotas
in a
> MySQL database.  I want to avoid backscatter completely, so I set
> "quota_full_tempfail = yes" and handle quota checking in the Exim
RCPT ACL
> during the SMTP session.  The problem lies in the case where a user's
> account is nearly full.  Smaller messages will continue to come through,
> but a larger message would get queued for retry since it will push the
> account over quota.  I need Dovecot's quota to exhibit the same
behavior as
> Exim's "quota_is_inclusive=false".
If backscatter is the only reason, would it work simply to keep
quota_full_tempfail=no and use -e option for deliver? Then configure Exim to
delay replying to to DATA command until deliver is finished. I guess the main
problem with this is increased load when tons of mails are being delivered at
the same time..