f2fs: show # of on-going flush and discard bios

This patch adds stat information for flush and discard commands.

Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 3a57d97..5d97310 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -206,6 +206,7 @@ struct discard_cmd_control {
 	wait_queue_head_t discard_wait_queue;	/* waiting queue for wake-up */
 	struct mutex cmd_lock;
 	int max_discards;			/* max. discards to be issued */
+	atomic_t submit_discard;		/* # of issued discard */
 };
 
 /* for the list of fsync inodes, used only during recovery */
@@ -2262,7 +2263,7 @@ struct f2fs_stat_info {
 	unsigned int ndirty_dirs, ndirty_files, ndirty_all;
 	int nats, dirty_nats, sits, dirty_sits, free_nids, alloc_nids;
 	int total_count, utilization;
-	int bg_gc, nr_wb_cp_data, nr_wb_data;
+	int bg_gc, nr_wb_cp_data, nr_wb_data, nr_flush, nr_discard;
 	int inline_xattr, inline_inode, inline_dir, orphans;
 	int aw_cnt, max_aw_cnt;
 	unsigned int valid_count, valid_node_count, valid_inode_count, discard_blks;