[PATCH] knfsd: Fix two problems that can cause rmmod nfsd to die

Both cause the 'entries' count in the export cache to be non-zero at module
removal time, so unregistering that cache fails and results in an oops.

1/ exp_pseudoroot (used for NFSv4 only) leaks a reference to an export
   entry.
2/ sunrpc_cache_update doesn't increment the entries count when it adds
   an entry.

Thanks to "david m.  richter" <[email protected]> for triggering the
problem and finding one of the bugs.

Cc: "david m. richter" <[email protected]>
Signed-off-by: Neil Brown <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

fs/nfsd/export.c

@@ -1066,9 +1066,11 @@ exp_pseudoroot(struct auth_domain *clp, struct svc_fh *fhp,
 		rv = nfserr_perm;
 	else if (IS_ERR(exp))
 		rv = nfserrno(PTR_ERR(exp));
-	else
+	else {
 		rv = fh_compose(fhp, exp,
 				fsid_key->ek_dentry, NULL);
+		exp_put(exp);
+	}
 	cache_put(&fsid_key->h, &svc_expkey_cache);
 	return rv;
 }

net/sunrpc/cache.c

@@ -159,6 +159,7 @@ struct cache_head *sunrpc_cache_update(struct cache_detail *detail,
 		detail->update(tmp, new);
 	tmp->next = *head;
 	*head = tmp;
+	detail->entries++;
 	cache_get(tmp);
 	is_new = cache_fresh_locked(tmp, new->expiry_time);
 	cache_fresh_locked(old, 0);