This pull request contains updates for both UBI and UBIFS:

- Minor bug fixes and improvements
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Merge tag 'tags/upstream-4.17-rc1' of git://git.infradead.org/linux-ubifs

Pull UBI and UBIFS updates from Richard Weinberger:
 "Minor bug fixes and improvements"

* tag 'tags/upstream-4.17-rc1' of git://git.infradead.org/linux-ubifs:
  ubi: Reject MLC NAND
  ubifs: Remove useless parameter of lpt_heap_replace
  ubifs: Constify struct ubifs_lprops in scan_for_leb_for_idx
  ubifs: remove unnecessary assignment
  ubi: Fix error for write access
  ubi: fastmap: Don't flush fastmap work on detach
  ubifs: Check ubifs_wbuf_sync() return code

drivers/mtd/ubi/block.c

@@ -244,7 +244,7 @@ static int ubiblock_open(struct block_device *bdev, fmode_t mode)
 	 * in any case.
 	 */
 	if (mode & FMODE_WRITE) {
-		ret = -EPERM;
+		ret = -EROFS;
 		goto out_unlock;
 	}
 

drivers/mtd/ubi/build.c

@@ -854,6 +854,17 @@ int ubi_attach_mtd_dev(struct mtd_info *mtd, int ubi_num,
 		return -EINVAL;
 	}
 
+	/*
+	 * Both UBI and UBIFS have been designed for SLC NAND and NOR flashes.
+	 * MLC NAND is different and needs special care, otherwise UBI or UBIFS
+	 * will die soon and you will lose all your data.
+	 */
+	if (mtd->type == MTD_MLCNANDFLASH) {
+		pr_err("ubi: refuse attaching mtd%d - MLC NAND is not supported\n",
+			mtd->index);
+		return -EINVAL;
+	}
+
 	if (ubi_num == UBI_DEV_NUM_AUTO) {
 		/* Search for an empty slot in the @ubi_devices array */
 		for (ubi_num = 0; ubi_num < UBI_MAX_DEVICES; ubi_num++)

drivers/mtd/ubi/fastmap-wl.c

@@ -362,7 +362,6 @@ static void ubi_fastmap_close(struct ubi_device *ubi)
 {
 	int i;
 
-	flush_work(&ubi->fm_work);
 	return_unused_pool_pebs(ubi, &ubi->fm_pool);
 	return_unused_pool_pebs(ubi, &ubi->fm_wl_pool);
 

fs/ubifs/find.c

@@ -632,7 +632,7 @@ static int scan_for_idx_cb(struct ubifs_info *c,
  */
 static const struct ubifs_lprops *scan_for_leb_for_idx(struct ubifs_info *c)
 {
-	struct ubifs_lprops *lprops;
+	const struct ubifs_lprops *lprops;
 	struct scan_data data;
 	int err;
 

fs/ubifs/lprops.c

@@ -244,7 +244,6 @@ static void remove_from_lpt_heap(struct ubifs_info *c,
 /**
  * lpt_heap_replace - replace lprops in a category heap.
  * @c: UBIFS file-system description object
- * @old_lprops: LEB properties to replace
  * @new_lprops: LEB properties with which to replace
  * @cat: LEB category
  *
@@ -254,7 +253,6 @@ static void remove_from_lpt_heap(struct ubifs_info *c,
  * lprops.  This function does that.
  */
 static void lpt_heap_replace(struct ubifs_info *c,
-			     struct ubifs_lprops *old_lprops,
 			     struct ubifs_lprops *new_lprops, int cat)
 {
 	struct ubifs_lpt_heap *heap;
@@ -362,7 +360,7 @@ void ubifs_replace_cat(struct ubifs_info *c, struct ubifs_lprops *old_lprops,
 	case LPROPS_DIRTY:
 	case LPROPS_DIRTY_IDX:
 	case LPROPS_FREE:
-		lpt_heap_replace(c, old_lprops, new_lprops, cat);
+		lpt_heap_replace(c, new_lprops, cat);
 		break;
 	case LPROPS_UNCAT:
 	case LPROPS_EMPTY:

fs/ubifs/scan.c

@@ -175,7 +175,6 @@ struct ubifs_scan_leb *ubifs_start_scan(const struct ubifs_info *c, int lnum,
 void ubifs_end_scan(const struct ubifs_info *c, struct ubifs_scan_leb *sleb,
 		    int lnum, int offs)
 {
-	lnum = lnum;
 	dbg_scan("stop scanning LEB %d at offset %d", lnum, offs);
 	ubifs_assert(offs % c->min_io_size == 0);
 

fs/ubifs/super.c

@@ -1737,8 +1737,11 @@ static void ubifs_remount_ro(struct ubifs_info *c)
 
 	dbg_save_space_info(c);
 
-	for (i = 0; i < c->jhead_cnt; i++)
-		ubifs_wbuf_sync(&c->jheads[i].wbuf);
+	for (i = 0; i < c->jhead_cnt; i++) {
+		err = ubifs_wbuf_sync(&c->jheads[i].wbuf);
+		if (err)
+			ubifs_ro_mode(c, err);
+	}
 
 	c->mst_node->flags &= ~cpu_to_le32(UBIFS_MST_DIRTY);
 	c->mst_node->flags |= cpu_to_le32(UBIFS_MST_NO_ORPHS);
@@ -1804,8 +1807,11 @@ static void ubifs_put_super(struct super_block *sb)
 			int err;
 
 			/* Synchronize write-buffers */
-			for (i = 0; i < c->jhead_cnt; i++)
-				ubifs_wbuf_sync(&c->jheads[i].wbuf);
+			for (i = 0; i < c->jhead_cnt; i++) {
+				err = ubifs_wbuf_sync(&c->jheads[i].wbuf);
+				if (err)
+					ubifs_ro_mode(c, err);
+			}
 
 			/*
 			 * We are being cleanly unmounted which means the