NFSD: Avoid using rqstp->rq_vers in nfsd_set_fh_dentry()

NFSD: Avoid using rqstp->rq_vers in nfsd_set_fh_dentry()

Currently, fh_verify() makes some daring assumptions about which
version of file handle the caller wants, based on the things it can
find in the passed-in rqstp. The about-to-be-introduced LOCALIO use
case sometimes has no svc_rqst context, so this logic won't work in
that case.

Instead, examine the passed-in file handle. It's .max_size field
should carry information to allow nfsd_set_fh_dentry() to initialize
the file handle appropriately.

The file handle used by lockd and the one created by write_filehandle
never need any of the version-specific fields (which affect things
like write and getattr requests and pre/post attributes).

Signed-off-by: Chuck Lever <[email protected]>
Signed-off-by: Mike Snitzer <[email protected]>
Reviewed-by: Jeff Layton <[email protected]>
Reviewed-by: NeilBrown <[email protected]>
Signed-off-by: Anna Schumaker <[email protected]>