Pigeonhole/sieve possibly corrupting mails

[Aki Tuomi]

> On October 20, 2016 at 8:03 PM Ladislav Laska <laska at kam.mff.cuni.cz> wrote:
> 
> 
> Hi!
> 
> > Somehow Dovecot thinks that the mbox file changed under it..
> 
> Yes. And it's probably right, but I wonder what could have changed it. I
> looked around inotify and it seems there is no way to let a file being
> watched and get program names/pids of processes accessing it.
> 
> > These mbox corruptions are usually pretty difficult to reproduce (= impossible to fix without ability to reproduce). You could try if you can (reliably) reproduce it in some way, e.g.:
> 
> I can reproduce them multiple times a day :-). But not on command, and
> probably not on another machine, I know...
> 
> > 1. Create a test folder: doveadm mailbox create -u krakonos testbox
> > 2. Use some combination of:
> >  * Save mail(s) to test folder: cat some-mails | doveadm save -u krakonos testbox
> >  * Try to read mails from test folder: doveadm fetch -u krakonos text mailbox testbox > /dev/null
> 
> Well, that's something. doveadm-save doesn't have a manpage, and there
> is nothing about it on wiki. Is it something new? Also, it doesn't seem
> to work. 
> 
> > 
> > The fetch should print similar errors to stderr in some way. I attempted to reproduce this way with your msg-error.mbox, but it worked ok.
> > 
> 
> Thinking about it, it might be that I'm fetching the message just as
> dovecot delivers another one. 
> 
> Is it possible that fcntl locking is just not working? I'm running a bit
> older kernel, if that could play a role in it. I'll try to enable
> dotlock even on read and see if the problem persists.
> 
> -- 
> S pozdravem Ladislav "Krakonoš" Láska                http://www.krakonos.org/

You could try running lsof in hopes of catching it. Might be rather difficult though. 

Aki