Re: [uml-devel] long comments on uml_moo for V2 COW

[Adam H. <ad...@do...>]

On Tue, 8 Jan 2002, Jeff Dike wrote:

> As for moving backing files around, I'm planning on making 'ubd0=cow,back'
> when the cow already knows what its backing file is to mean that back has
> been moved and the header should be updated.  The mtime and size checks
> will still apply.  If the move is across filesystems, then the mtime check
> will fail, leaving us with the size, which is a bit thin.  My thinking
> right now is that we make the admin manually set the mtime back as a promise
> that this really is the same backing file.

Why not use some simple, quick, crc check?  If not on the whole file, then
take one byte every 512 bytes, and crc that?

This isn't too bad, as it should only be done when loading.