Timo Sirainen tss@iki.fi writes:
Looks like maildir can't be used very realiably without quite a lot of locking. Writing and scanning the directory would have to be locked, but reading wouldn't (as long as the file hasn't been renamed which would require scanning to find it). So much for "no locks needed"..
The problem is that opendir()/readdir() may temporarily not return some files if there has been changes in the directory since the opendir(). That means Dovecot thinks a message is expunged, while in fact it really isn't, and the next scan would usually show it again.
I'm not sure if the claims are about locking-free scanning (but I believe DJB of Bold Yet Hollow Announcements fame just touted "no locks"); one point is locking-free delivery because if opendir/readdir misses a _new_ file, no harm is done.
qmail is so full of bugs I effectively stopped maintaining my qmail-bugs page because I grew tired of researching bugs of a system I stopped using years ago and wackos refuting the bugs http://home.pages.de/~mandree/qmail-bugs.html, I only recently found out that qmail-pop3d doesn't get article sizes (in LIST) right. Shame on DJB for claiming efficiency and standards compliance when his nutshell is rather shipwreck, and has been unmaintained for six years...
-- Matthias Andree