ubi: Correct the number of PEBs after a volume resize failure

In the error handling path `out_acc` of `ubi_resize_volume()`,
when `pebs < 0`, it indicates that the volume table record failed to
update when the volume was shrunk. In this case, the number of `ubi->avail_pebs`
and `ubi->rsvd_pebs` should be restored to their previous values to prevent
the UBI layer from reporting an incorrect number of available PEBs.
Signed-off-by: ZhaoLong Wang <wangzhaolong1@huawei.com>
Reviewed-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

drivers/mtd/ubi/vmt.c

@@ -515,13 +515,12 @@ int ubi_resize_volume(struct ubi_volume_desc *desc, int reserved_pebs)
 out_acc:
 	spin_lock(&ubi->volumes_lock);
 	vol->reserved_pebs = reserved_pebs - pebs;
-	if (pebs > 0) {
-		ubi->rsvd_pebs -= pebs;
-		ubi->avail_pebs += pebs;
+	ubi->rsvd_pebs -= pebs;
+	ubi->avail_pebs += pebs;
+	if (pebs > 0)
 		ubi_eba_copy_table(vol, old_eba_tbl, vol->reserved_pebs);
-	} else {
+	else
 		ubi_eba_copy_table(vol, old_eba_tbl, reserved_pebs);
-	}
 	vol->eba_tbl = old_eba_tbl;
 	spin_unlock(&ubi->volumes_lock);
 out_free: