Re: VFS + path walktrough

From: Trond Myklebust
Date: Mon May 05 2008 - 16:17:26 EST


On Mon, 2008-05-05 at 20:31 +0200, Miklos Szeredi wrote:
> > > > > Take a look at 9P walk - it does *not* give
> > > > > you anything resembling stat, you just get qids of intermediates.
> > > >
> > > > Which is exactly what's needed to populate the dentry tree, no?
> > >
> > > No - you need inodes as well (i.e. as the absolute least you want
> > > mode and ownership). Which is to say, you need to issue stat on
> > > each component in such situation anyway. Not a win...
>
> And actually even that *could* be a win, if the network latency is
> large. Because by doing the lookup first, the stats can be performed
> in parallel. So a path with an arbitrary number of components could
> be resolved in just 2 RTTs.

...and NFSv4 could do it in a single RPC call (assuming no symlinks or
submounts).

Cheers
Trond

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