ext4: make mb_check_counter per group

Make bb_check_counter per group, so each group has the same chance
to be checked, which can expose errors more easily.

Signed-off-by: Chunguang Xu <brookxu@tencent.com>
Link: https://lore.kernel.org/r/1601292995-32205-2-git-send-email-brookxu@tencent.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

fs/ext4/ext4.h

@@ -3154,6 +3154,9 @@ int ext4_update_disksize_before_punch(struct inode *inode, loff_t offset,
 
 struct ext4_group_info {
 	unsigned long   bb_state;
+#ifdef AGGRESSIVE_CHECK
+	unsigned long	bb_check_counter;
+#endif
 	struct rb_root  bb_free_root;
 	ext4_grpblk_t	bb_first_free;	/* first free block */
 	ext4_grpblk_t	bb_free;	/* total free blocks */

fs/ext4/mballoc.c

@@ -619,11 +619,8 @@ static int __mb_check_buddy(struct ext4_buddy *e4b, char *file,
 	void *buddy;
 	void *buddy2;
 
-	{
-		static int mb_check_counter;
-		if (mb_check_counter++ % 100 != 0)
-			return 0;
-	}
+	if (e4b->bd_info->bb_check_counter++ % 10)
+		return 0;
 
 	while (order > 1) {
 		buddy = mb_find_buddy(e4b, order, &max);