Let's do GC as much as possible, while gc_urgent is set.
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
                 * invalidated soon after by user update or deletion.
                 * So, I'd like to wait some time to collect dirty segments.
                 */
-               if (!mutex_trylock(&sbi->gc_mutex))
-                       goto next;
-
                if (gc_th->gc_urgent) {
                        wait_ms = gc_th->urgent_sleep_time;
+                       mutex_lock(&sbi->gc_mutex);
                        goto do_gc;
                }
 
+               if (!mutex_trylock(&sbi->gc_mutex))
+                       goto next;
+
                if (!is_idle(sbi)) {
                        increase_sleep_time(gc_th, &wait_ms);
                        mutex_unlock(&sbi->gc_mutex);