project quota: df/reservations

[Jerzy Borkowski]

Hello,

1) Fancy a project with quota set to 10GB, and filled
with 5GB of data. When I type

  df /path/to/project/tree

it shows 5GB free space. Now, the root user
fills up the disk (outside project tree), so the
XFS filesystem is really 100% full. The df command
still shows 5GB free space. I guess, this is
intentional. I propose to add some switch/flag
(either during mount or project creation),
which would tell XFS to report in statfs() calls
the free space as: min(project_free_space, filesystem_free_space).

2) is there any way to have space reservations for projects (like in ZFS) ?
For instance, a project with 10GB quota and 7GB of preallocated
space, so even root, writing outside the project tree, cannot
completely fill up the disk.

Thanks,

Jurek