Subject: RE: file_id (correction)

From: "Noveck, Dave" <[email-masked]>
Date: Wed, 4 Dec 2002 07:41:22 -0800

Jim Ress asked (in connection with a snapshot image of a file
having the same file-id as the fiel itself:

> > But your snapshot image must have a different fsid, right?
>

And I responded, incorrectly as it turns out:

> No, it isn't.  We make the all of the snapshots for a given 
> directory visible under a .snapshot sub-directory of that 
> original directory.  
>
> In the past, that was part of the same fs, because v2/v3 didn't
> really give you any choice.  With V4 you have a choice, but so far
> we've kept to the v2/v3 handling of this, partly due to inertia,
> and partly because some clients aren't able to do the automatic 
> nested mounts.

In fact, we do give the snapshot image its own distinct fsid.  We
have always returned this as the fsid attribute even for v2/v3.
V2/V3 clients, however, didn't look at this so the user would
see two files with the same file-id and the same fsid which was
derived from the one the client assigned to the overall mount, 
including the filer's active file system and all the associated
snapshot images