ext4: convert number of blocks to clusters properly

We're using macro EXT4_B2C() to convert number of blocks to number of
clusters for bigalloc file systems.  However, we should be using
EXT4_NUM_B2C().

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@vger.kernel.org
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 6ac9c8a..990ceab 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3162,7 +3162,7 @@
 	}
 	/* Add the journal blocks as well */
 	if (sbi->s_journal)
-		overhead += EXT4_B2C(sbi, sbi->s_journal->j_maxlen);
+		overhead += EXT4_NUM_B2C(sbi, sbi->s_journal->j_maxlen);
 
 	sbi->s_overhead = overhead;
 	smp_wmb();