hulk inclusion
category: feature
bugzilla: 173267
CVE: NA
---------------------------

If ra->prev_pos page index is equal to current pos, that means
it is sequential read, then clear FMODE_RANDOM flag to enable
async readahead.

Usage:
	make -C bpf
	./test_xfs_file clear

Signed-off-by: Yufen Yu <yuyufen@huawei.com>
Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Reviewed-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>