Re: [PATCH] cifs: Allow nfsd over cifs

["J. Bruce Fields" <bfields-uC3wQj2KruNg9hUCZPvPmw@public.gmane.org>]

On Mon, Feb 28, 2011 at 04:58:57PM -0600, Steve French wrote:
> On Mon, Feb 28, 2011 at 4:49 PM, J. Bruce Fields <bfields-uC3wQj2KruMpug/h7KTFAQ@public.gmane.orgg> wrote:
> > On Mon, Feb 28, 2011 at 03:52:41PM -0600, shirishpargaonkar@gmail.com wrote:
> >> +static struct dentry *
> >> +cifs_fh_to_dentry(struct super_block *sb, struct fid *fh,
> >> +                     int fh_len, int fh_type)
> >> +{
> >> +     struct cifs_fid *cfid = (struct cifs_fid *)fh;
> >> +     struct inode *inode = NULL;
> >> +     struct cifs_fattr fattr;
> >> +
> >>
> >> -#endif /* CIFS_NFSD_EXPORT */
> >> +     if (fh_type != FILEID_INO32_GEN && fh_type != FILEID_INO32_GEN_PARENT) {
> >> +             cERROR(1, "%s: Can't handle fh type: %d", __func__, fh_type);
> >> +             return ERR_PTR(-EINVAL);
> >> +     }
> >>
> >> +     if (!cfid->cino)
> >> +             return ERR_PTR(-ESTALE);
> >> +
> >> +     fattr.cf_uniqueid = cfid->cino;
> >> +     inode = iget5_locked(sb, cfid->cino, cifs_find_inode_id,
> >> +                                     cifs_init_inode, &fattr);
> >> +     if (IS_ERR(inode))
> >> +             return ERR_CAST(inode);
> >> +
> >> +     return d_obtain_alias(inode);
> >
> > Does the cifs protocol give the client a way to look up a file by inode
> > number (or filehandle or equivalent?).
> 
> There is a unique identifier similar to inode number returned by
> various info calls,
> but cifs calls use either a file handle (returned by an open) or path name to
> look up metadata on a file.
> 
> Not sure whether the unique identifier can be passed in as input to an
> ioctl useful here.

OK.  Then as things stand we're stuck returning ESTALE to the client
unless we happen to have the inode they're looking for in our cache?

--b.