On Mon, Dec 23, 2019 at 09:08:28PM +0800, Ming Lei wrote: > > From the above trace: > > b'blk_mq_sched_request_inserted' > b'blk_mq_sched_request_inserted' > b'dd_insert_requests' > b'blk_mq_sched_insert_requests' > b'blk_mq_flush_plug_list' > b'blk_flush_plug_list' > b'io_schedule_prepare' > b'io_schedule' > b'rq_qos_wait' > b'wbt_wait' > b'__rq_qos_throttle' > b'blk_mq_make_request' > b'generic_make_request' > b'submit_bio' > b'ext4_io_submit' > b'ext4_writepages' > b'do_writepages' > b'__filemap_fdatawrite_range' > b'ext4_release_file' > b'__fput' > b'task_work_run' > b'exit_to_usermode_loop' > b'do_syscall_64' > b'entry_SYSCALL_64_after_hwframe' > b'cp' [19863] > 4400 > > So this write is clearly from 'cp' process, and it should be one > ext4 fs issue. We need a system call trace of the cp process, to understand what system call is resulting in fput, (eg., I assume it's close(2) but let's be sure), and often it's calling that system call. What cp process is it? Is it from shellutils? Is it from busybox? - Ted