[Lustre-devel] Re: fixing redundant network opens on Linux file creation

[Peter Braam]

Bryan, 

On Wed, Jan 08, 2003 at 06:08:48PM -0800, Bryan Henderson wrote:
> 
> 
> 
> 
> >I have no objections to a name change.  We are not so religious about
> >"intent" as a name.
> 
> How religious are you about the idea of having to have BOTH a lookup2()
> that contains all the information necessary to create a directory if the
> name is available, AND a subsequent "create directory" call?  Because once
> you remove the word "intent" from the description, that looks even more
> silly.

Good question.  For mkdir your solution is much preferrable.   So no
religion here at all.  But mkdir is an easy case, possibly the easiest.

For open, rename, setattr and dealing with symbolic links we found
having the separation of the lookup phase with intents and actual
execution to be quite useful, since the symbolic links may bring you
back to another file system.

> It is the relationship between those two (sometimes 3) redundant calls that
> is the real substance in what otherwise appears to be just a naming issue.

Yes, and the answer is "sometimes" - in the mkdir case it (moderately)
easy to give the whole task to the file system (symlinks remain
hairy), in open, rename, setattr we found a lot of useful VFS
functionality between lookup and operation.

- Peter -