nfsd4: name->id mapping should fail with BADOWNER not BADNAME

According to rfc 3530 BADNAME is for strings that represent paths;
BADOWNER is for user/group names that don't map.

And the too-long name should probably be BADOWNER as well; it's
effectively the same as if we couldn't map it.

Cc: stable@kernel.org
Reported-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Reported-by: Simon Kirby <sim@hostway.ca>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
diff --git a/fs/nfsd/nfs4idmap.c b/fs/nfsd/nfs4idmap.c
index f0695e8..844960f 100644
--- a/fs/nfsd/nfs4idmap.c
+++ b/fs/nfsd/nfs4idmap.c
@@ -524,13 +524,13 @@
 	int ret;
 
 	if (namelen + 1 > sizeof(key.name))
-		return -EINVAL;
+		return -ESRCH; /* nfserr_badowner */
 	memcpy(key.name, name, namelen);
 	key.name[namelen] = '\0';
 	strlcpy(key.authname, rqst_authname(rqstp), sizeof(key.authname));
 	ret = idmap_lookup(rqstp, nametoid_lookup, &key, &nametoid_cache, &item);
 	if (ret == -ENOENT)
-		ret = -ESRCH; /* nfserr_badname */
+		ret = -ESRCH; /* nfserr_badowner */
 	if (ret)
 		return ret;
 	*id = item->id;