fixing redundant network opens on Linux file creation

[Bryan Henderson]

>In our code, the lookup-with-intent actually performs both of the
operations
>on the server,

What I don't get is why is the concept of "intent" even involved here?  If
lookup-with-intent does the lookup and open (and, I guess, create where
appropriate), why don't you call it "lookup-and-open" and then skip the
subsequent VFS open call?

You also mention the distributed version of the Lustre lookup-with-intent:

>OR it returns a lock to the client that grants the client exclusive
>   control over the item(s) in question (normally the parent dir(s)) and
>   lets the client do the operations locally and send the operations to
>   the server separately.

and the same question applies in that case.  While the client may do the
open separately, there's no reason it shouldn't do it before returning from
the VFS lookup-with-intent call, which means it would be simpler as a
lookup-and-open.