Re: Bug#43529: debian-policy: mail locking in Debian is _not_ NFS safe

[Philip Hands <phil@hands.com>]

"Marco d'Itri" <md@linux.it> writes:

> On Aug 26, Jason Gunthorpe <jgg@ualberta.ca> wrote:
>  
>  >> But only fcntl() locking is not enough, because Linux 2.0.* doesn't
>  >> support this over NFS and then we have no locking over NFS.
>  >
>  >And linux 2.2.x with a userland server also does not support fcntl
>  >locking, it generates an annoying kernel message and fails with ENOLCK.
> Fine, then users should not read mail from 2.2 servers with user space
> nfsd, because it is not reliable.

mbox format mail is not safe over NFS even if there is locking.

Let me put that another way, mbox format is not safe:

  http://www.qmail.org/man/misc/INSTALL.maildir.txt

So perhaps we should mandate that all mail programs should be capable
of using Maildir format, which is NFS safe without needing locks, and
adopt that as our default.

OK, so that's slightly tongue in cheek, but it would be a noble goal
to aim for, and might even be feasible, and if we did it we'd have the
first Linux distribution that ships with crashproof e-mail.

Cheers, Phil.