[dm-devel] Re: [PATCH 3/3] Add timeout feature

[Dave Chinner <david fromorbit com>]

On Mon, Jul 07, 2008 at 01:07:31PM +0200, Pavel Machek wrote:
> Hi!
> 
> > I still disagree with this whole patch.  There is not reason to let
> > the freeze request timeout - an auto-unfreezing will only confuse the
> > hell out of the caller.  The only reason where the current XFS freeze
> > call can hang and this would be theoretically useful is when the
> 
> What happens when someone dirties so much data that vm swaps out
> whatever process that frozen the filesystem?

a) you can't dirty a frozen filesystem - by definition a frozen
   filesystem is a *clean filesystem* and *cannot be dirtied*.
b) Swap doesn't write through the filesystem
c) you can still read from a frozen filesystem to page your
   executableѕ in.
d) if dirtying another unfrozen filesystem swaps out your
   application so it can't run, then there's a major VM bug.
   Regardless, until the app completes it is relying on the
   filesystem being frozen, so it better remain frozen....

> I though that was why the timeout was there...

Not that I know of. 

Cheers,

Dave.
-- 
Dave Chinner
david fromorbit com