Re: Safe File Update (atomic)

[Ted Ts'o <tytso@mit.edu>]

On Wed, Jan 05, 2011 at 10:47:03PM +0100, Olaf van der Spek wrote:
> 
> That was about soft updates. I'm not sure this is just as complex.

Then I invite you to implement it, and start discovering all of the
corner cases for yourself.  :-)  As I predicted, you're not going to
believe me when I tell you it's too hard.

> I was thinking, doesn't ext have this kind of dependency tracking already?
> It has to write the inode after writing the data, otherwise the inode
> might point to garbage.

No, it doesn't.  We use journaling, and forced data writeouts, to
ensure consistency.

       		     	      	     		- Ted