FM / loop0

/sys/fs/ext4/loop0

Name	Size	Mode	Actions
delayed_allocation_blocks	4096	0444	edit dl rm
errors_count	4096	0444	edit dl rm
err_ratelimit_burst	4096	0644	edit dl rm
err_ratelimit_interval_ms	4096	0644	edit dl rm
extent_max_zeroout_kb	4096	0644	edit dl rm
first_error_time	4096	0444	edit dl rm
inode_goal	4096	0644	edit dl rm
inode_readahead_blks	4096	0644	edit dl rm
journal_task	4096	0444	edit dl rm
last_error_time	4096	0444	edit dl rm
lifetime_write_kbytes	4096	0444	edit dl rm
max_writeback_mb_bump	4096	0444	edit dl rm
mb_group_prealloc	4096	0644	edit dl rm
mb_max_to_scan	4096	0644	edit dl rm
mb_min_to_scan	4096	0644	edit dl rm
mb_order2_req	4096	0644	edit dl rm
mb_stats	4096	0644	edit dl rm
mb_stream_req	4096	0644	edit dl rm
msg_ratelimit_burst	4096	0644	edit dl rm
msg_ratelimit_interval_ms	4096	0644	edit dl rm
reserved_clusters	4096	0644	edit dl rm
session_write_kbytes	4096	0444	edit dl rm
trigger_fs_error	4096	0200	edit dl rm
warning_ratelimit_burst	4096	0644	edit dl rm
warning_ratelimit_interval_ms	4096	0644	edit dl rm

Edit: /sys/fs/ext4/loop0/mb_stats (4096B)