UBIFS: remount ro fixes

- preserve the idx_gc list - it will be needed in the same
state, should UBIFS be remounted rw again
- prevent remounting ro if we have switched to read only
mode (due to a fatal error)

Signed-off-by: Adrian Hunter <ext-adrian.hunter@nokia.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
diff --git a/fs/ubifs/gc.c b/fs/ubifs/gc.c
index bad3339..a711d33 100644
--- a/fs/ubifs/gc.c
+++ b/fs/ubifs/gc.c
@@ -830,29 +830,21 @@
  * ubifs_destroy_idx_gc - destroy idx_gc list.
  * @c: UBIFS file-system description object
  *
- * This function destroys the @c->idx_gc list. It is called when unmounting or
- * remounting read-only so locks are not needed. Returns zero in case of
- * success and a negative error code in case of failure.
+ * This function destroys the @c->idx_gc list. It is called when unmounting
+ * so locks are not needed. Returns zero in case of success and a negative
+ * error code in case of failure.
  */
-int ubifs_destroy_idx_gc(struct ubifs_info *c)
+void ubifs_destroy_idx_gc(struct ubifs_info *c)
 {
-	int ret = 0;
-
 	while (!list_empty(&c->idx_gc)) {
-		int err;
 		struct ubifs_gced_idx_leb *idx_gc;
 
 		idx_gc = list_entry(c->idx_gc.next, struct ubifs_gced_idx_leb,
 				    list);
-		err = ubifs_change_one_lp(c, idx_gc->lnum, LPROPS_NC,
-					  LPROPS_NC, 0, LPROPS_TAKEN, -1);
-		if (err && !ret)
-			ret = err;
+		c->idx_gc_cnt -= 1;
 		list_del(&idx_gc->list);
 		kfree(idx_gc);
 	}
-
-	return ret;
 }
 
 /**