Linux-libre 4.6.2-gnu

1 files changed, 19 insertions, 2 deletions

diff --git a/drivers/mtd/ubi/eba.c b/drivers/mtd/ubi/eba.c
index 5b9834cf2..96fddb016 100644
--- a/drivers/mtd/ubi/eba.c
+++ b/drivers/mtd/ubi/eba.c
@@ -426,8 +426,25 @@ retry:
 						 pnum, vol_id, lnum);
 					err = -EBADMSG;
 				} else {
-					err = -EINVAL;
-					ubi_ro_mode(ubi);
+					/*
+					 * Ending up here in the non-Fastmap case
+					 * is a clear bug as the VID header had to
+					 * be present at scan time to have it referenced.
+					 * With fastmap the story is more complicated.
+					 * Fastmap has the mapping info without the need
+					 * of a full scan. So the LEB could have been
+					 * unmapped, Fastmap cannot know this and keeps
+					 * the LEB referenced.
+					 * This is valid and works as the layer above UBI
+					 * has to do bookkeeping about used/referenced
+					 * LEBs in any case.
+					 */
+					if (ubi->fast_attach) {
+						err = -EBADMSG;
+					} else {
+						err = -EINVAL;
+						ubi_ro_mode(ubi);
+					}
 				}
 			}
 			goto out_free;