Disk quotas: edquota -t has no effect (9.2, 10.0)

[Fred Condo]

Having searched the archives, PRs, and famous search engines to no avail, I
turn now to the list. I have one system for which I would like to use group
disk quotas, but edquota -t has no effect - not for users, not for groups,
not for times > 7 days, nor for times < 7 days. The grace period stubbornly
sticks at 7 days.

I've had a look at relevant source code, but as I'm not a kernel/filesystem
hacker, it was not obvious to me where the problem may lie.

In this particular case, I would actually like to set a longer grace period
than the default. I would prefer not to maintain a custom kernel, but will
if necessary. Anyone have any advice on manipulating the grace period?
Thanks.