f2fs: wake up gc thread immediately when gc_urgent is set

Fixes: 5b0e9539 ("f2fs: introduce sbi->gc_mode to determine the policy")
Signed-off-by: Sheng Yong <shengyong1@huawei.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/sysfs.c

@@ -253,6 +253,7 @@ static ssize_t __sbi_store(struct f2fs_attr *a,
 		if (t >= 1) {
 			sbi->gc_mode = GC_URGENT;
 			if (sbi->gc_thread) {
+				sbi->gc_thread->gc_wake = 1;
 				wake_up_interruptible_all(
 					&sbi->gc_thread->gc_wait_queue_head);
 				wake_up_discard_thread(sbi, true);