Defer email via LMTP when there is 'no space left on device' instead of rejecting it

[Timo Sirainen]

On 05 Aug 2014, at 14:45, Christian Rohmann <crohmann at netcologne.de> wrote:

> may I PING this subject once again to maybe get Timo's opinion.
> 
> On 23.07.2014 11:26, Christian Rohmann wrote:
>> Bounced / rejected messages for something that will be usually be
>> resolved very quickly and the messages can then be delivered after all
>> is just not very nice for users. The admin made a mistake and the users
>> have to deal with the problems is just not my approach.
>> 
>> But in the end I don't even want to argue that rejecting the messages
>> might not be a valid behavior for some. That's why I suggested to make
>> this configurable, just like the quota behavior.
> 
> I'd really like to hear Timo's view on having lmtp do a (configurable)
> DEFER when the disk is full which is, most likely, a "temporary" error.

My opinion: It shouldn't be configurable - it should always cause temporary error. The only thing I'm slightly worried about is if write failures because of "user's filesystem quota full" will always return EDQUOT error for write() instead of ENOSPC, but I suppose they will in any modern OS. And it would require changing MAIL_ERROR_NOSPACE definition a bit inside Dovecot, but that's less of an issue.

I'll change this once I have some time&energy. Patches welcome also.