UBIFS: introduce categorized lprops counter

This commit is a preparation for a subsequent bugfix. We introduce a
counter for categorized lprops.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Cc: stable@vger.kernel.org
diff --git a/fs/ubifs/lprops.c b/fs/ubifs/lprops.c
index e5a2a35..46190a7 100644
--- a/fs/ubifs/lprops.c
+++ b/fs/ubifs/lprops.c
@@ -300,8 +300,11 @@
 	default:
 		ubifs_assert(0);
 	}
+
 	lprops->flags &= ~LPROPS_CAT_MASK;
 	lprops->flags |= cat;
+	c->in_a_category_cnt += 1;
+	ubifs_assert(c->in_a_category_cnt <= c->main_lebs);
 }
 
 /**
@@ -334,6 +337,9 @@
 	default:
 		ubifs_assert(0);
 	}
+
+	c->in_a_category_cnt -= 1;
+	ubifs_assert(c->in_a_category_cnt >= 0);
 }
 
 /**