On Jan 15, 2014, at 1:12 AM, Zheng Liu [off-list ref] wrote:

On Mon, Dec 23, 2013 at 12:42:22PM +1100, Dave Chinner wrote:

quoted

I'd also strongly suggest that you use the XFS userspace quota API
for managing project quotas, so that we can use the same management
tools and tests to verify that they behave the same. Please don't
invent a new version of the quota API to implement this - everything
you need ifor managing project/directory quotas is already there in
xfs_quota.....

Frankly, I don't like this, really.  Now we have quota-tool to manage
the quota in ext4.  So IMHO we'd better go on using this tool because it
is natural for ext4 users.  I still couldn't accept this fact that I
need to install xfsprogs for using a feature of ext4.  Further, it could
make users puzzled because they use quota to control user/group quota in
ext4, but it uses xfs_quota to control project quota.  It could bring
some troubles for the ext4 users who have written some scripts to manage
their machines.

Please see Li Xi's recent email "Directory/Project quota supports" on
the linux-ext4 list.  He has already added some prototype support for
project quotas to quota-tools.

I think it might make sense to keep the same API as XFS for the ext4
quotas (to keep compatibility for existing XFS deployments), but add
support into quota-tools so that it is usable by all filesystems.

Cheers, Andreas