data loss from failed link

[Andreas Pflug]

Lately, I've been moving MailScanner's in and out exim queues to a xfs
file system, and configuring quota projects on both queues (no limits
applied).

After a while I noticed that the out queue would contain only xxx-H
files, no message body xxx-D files any more. The logfile would state
"Failed to link message body between queues". Apparently the creation of
a hard link failes if the target directory is in a different xfs quota
project.

Unfortunately, the check in EximDiskStore.pm LinkData() (line 256) just
logs a message and continues, deleting the non-linked message and thus
losing data. Instead of Log::WarnLog a Log::DieLog should be generated,
because losing data on misconfigured storage isn't acceptable.

Regards
Andreas