ubifs: Add auth nodes to garbage collector journal head

To be able to authenticate the garbage collector journal head add
authentication nodes to the buds the garbage collector creates.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Richard Weinberger <richard@nod.at>

fs/ubifs/gc.c

@@ -365,12 +365,13 @@ static int move_nodes(struct ubifs_info *c, struct ubifs_scan_leb *sleb)
 
 	/* Write nodes to their new location. Use the first-fit strategy */
 	while (1) {
-		int avail;
+		int avail, moved = 0;
 		struct ubifs_scan_node *snod, *tmp;
 
 		/* Move data nodes */
 		list_for_each_entry_safe(snod, tmp, &sleb->nodes, list) {
-			avail = c->leb_size - wbuf->offs - wbuf->used;
+			avail = c->leb_size - wbuf->offs - wbuf->used -
+					ubifs_auth_node_sz(c);
 			if  (snod->len > avail)
 				/*
 				 * Do not skip data nodes in order to optimize
@@ -378,14 +379,21 @@ static int move_nodes(struct ubifs_info *c, struct ubifs_scan_leb *sleb)
 				 */
 				break;
 
+			err = ubifs_shash_update(c, c->jheads[GCHD].log_hash,
+						 snod->node, snod->len);
+			if (err)
+				goto out;
+
 			err = move_node(c, sleb, snod, wbuf);
 			if (err)
 				goto out;
+			moved = 1;
 		}
 
 		/* Move non-data nodes */
 		list_for_each_entry_safe(snod, tmp, &nondata, list) {
-			avail = c->leb_size - wbuf->offs - wbuf->used;
+			avail = c->leb_size - wbuf->offs - wbuf->used -
+					ubifs_auth_node_sz(c);
 			if (avail < min)
 				break;
 
@@ -403,9 +411,41 @@ static int move_nodes(struct ubifs_info *c, struct ubifs_scan_leb *sleb)
 				continue;
 			}
 
+			err = ubifs_shash_update(c, c->jheads[GCHD].log_hash,
+						 snod->node, snod->len);
+			if (err)
+				goto out;
+
 			err = move_node(c, sleb, snod, wbuf);
 			if (err)
 				goto out;
+			moved = 1;
+		}
+
+		if (ubifs_authenticated(c) && moved) {
+			struct ubifs_auth_node *auth;
+
+			auth = kmalloc(ubifs_auth_node_sz(c), GFP_NOFS);
+			if (!auth) {
+				err = -ENOMEM;
+				goto out;
+			}
+
+			err = ubifs_prepare_auth_node(c, auth,
+						c->jheads[GCHD].log_hash);
+			if (err) {
+				kfree(auth);
+				goto out;
+			}
+
+			err = ubifs_wbuf_write_nolock(wbuf, auth,
+						      ubifs_auth_node_sz(c));
+			if (err) {
+				kfree(auth);
+				goto out;
+			}
+
+			ubifs_add_dirt(c, wbuf->lnum, ubifs_auth_node_sz(c));
 		}
 
 		if (list_empty(&sleb->nodes) && list_empty(&nondata))