Re: RFC - tree quotas for Linux (2.4.12, ext2)

[Jesse Pollard <pollard@tomcat.admin.navo.hpc.mil>]

James Sutherland <jas88@cam.ac.uk>:
> On Wed, 24 Oct 2001, Rik van Riel wrote:
> > On Wed, 24 Oct 2001, James Sutherland wrote:
> >
> > > Yep, you're right: you'd need to ascend the target directory tree,
> > > increasing the cumulative size all the way up, then do the move and
> > > decrement the old location's totals in the same way. All wrapped up in a
> > > transaction (on journalled FSs) or have fsck rebuild the totals on a dirty
> > > mount. Fairly clean and painless on a JFS,
> >
> > It's only clean and painless when you have infinite journal
> > space. When your filesystem's journal isn't big enough to
> > keep track of all the quota updates from an arbitrarily deep
> > directory tree, you're in big trouble.
> 
> Good point. You should be able to do it in constant space, though:
> identify the directory being modified, and the "height" to which you have
> ascended so far. That'll allow you to back out or redo the transaction
> later, which is enough I think?

There still remains the problem of hard links... They could be counted
in two or more trees as long as two or more trees exist on one filesystem.

-------------------------------------------------------------------------
Jesse I Pollard, II
Email: pollard@navo.hpc.mil

Any opinions expressed are solely my own.