ceph: Convert struct ceph_mds_request to use kuid_t and kgid_t

Hold the uid and gid for a pending ceph mds request using the types
kuid_t and kgid_t.  When a request message is finally created convert
the kuid_t and kgid_t values into uids and gids in the initial user
namespace.

Cc: Sage Weil <sage@inktank.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

fs/ceph/mds_client.c

@@ -1658,8 +1658,8 @@ static struct ceph_msg *create_request_message(struct ceph_mds_client *mdsc,
 
 	head->mdsmap_epoch = cpu_to_le32(mdsc->mdsmap->m_epoch);
 	head->op = cpu_to_le32(req->r_op);
-	head->caller_uid = cpu_to_le32(req->r_uid);
-	head->caller_gid = cpu_to_le32(req->r_gid);
+	head->caller_uid = cpu_to_le32(from_kuid(&init_user_ns, req->r_uid));
+	head->caller_gid = cpu_to_le32(from_kgid(&init_user_ns, req->r_gid));
 	head->args = req->r_args;
 
 	ceph_encode_filepath(&p, end, ino1, path1);

fs/ceph/mds_client.h

@@ -184,8 +184,8 @@ struct ceph_mds_request {
 
 	union ceph_mds_request_args r_args;
 	int r_fmode;        /* file mode, if expecting cap */
-	uid_t r_uid;
-	gid_t r_gid;
+	kuid_t r_uid;
+	kgid_t r_gid;
 
 	/* for choosing which mds to send this request to */
 	int r_direct_mode;