Re: Reading/changing projid of a symlink

[Dave Chinner <david@fromorbit.com>]

On Tue, Jun 12, 2018 at 03:17:27PM -0700, Ilya Pronin wrote:
> So the only way to remove a symlink from a project is to remove it?
> 
> Here's my use case. In Apache Mesos we use XFS project quotas for disk
> space isolation. Every container sandbox is allocated its own project
> ID. When the container terminates its project ID is unset from the
> sandbox and files inside it, and can be used for other containers.
> Sandboxes of terminated containers stay on the host for some time for
> debugging, etc. With such approach the inability to remove projid from
> symlinks presents a small problem: when a project ID is reused for a
> new container, any lingering symlinks that still have that project ID
> will contribute to disk usage of the new container. Typically not
> much, but still that's inaccurate. I guess we'll need to change when
> we "deallocate" projids.

XFS has a 32bit project ID space, so you really don't need to reuse
project IDs at all. Just keep incrementing the new container ID, and
maybe after a couple of billion project IDs have been consumed you
can look at reclaiming/recycling/resetting the new ID counter?

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com