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

[Christoph Hellwig <hch infradead org>]

On Mon, Sep 29, 2008 at 09:36:04AM -0500, Eric Sandeen wrote:
> Christoph Hellwig wrote:
> > On Fri, Sep 26, 2008 at 05:52:35PM +0900, Takashi Sato wrote:
> >> I think that your concern is that the freezer cannot recognize the occurrence
> >> of a timeout and it continues the backup process and the backup data is
> >> corrupted finally.
> > 
> > What timeout should happen?  the freeze ioctl must not return until the
> > filesystem is a clean state and all writes are blocked.
> 
> The suggestion was that *UN*freeze would return ETIMEDOUT if the
> filesystem had already unfrozen itself, I think.  That way you know that
> the snapshot you just took is worthless, at least.

But why would the filesystem every unfreeze itself?  That defeats the
whole point of freezing it.