From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steven Scholz Subject: Re: when are buffers/caches flushed? Date: Thu, 18 Aug 2005 14:12:13 +0200 Message-ID: <43047B1D.9010601@imc-berlin.de> References: <43046817.803@imc-berlin.de> <43046FD2.4080401@gmail.com> <43047229.7010007@imc-berlin.de> <43047830.4060705@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail.imc-berlin.de ([217.110.46.186]:7179 "EHLO mail.imc-berlin.de") by vger.kernel.org with ESMTP id S932214AbVHRMMR (ORCPT ); Thu, 18 Aug 2005 08:12:17 -0400 In-Reply-To: <43047830.4060705@gmail.com> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Tejun Heo Cc: Bartlomiej Zolnierkiewicz , linux-ide@vger.kernel.org Tejun, >>>> How about recent kernels? Does sync() block until buffers are flushed? >>>> How can I find out if the disk caches are actually flushed? >>>> >>>> I want to make sure that all data is flushed to my disk drive before >>>> powering down the system. >>> >>> All disk caches are flushed before shutdown via the following path. >>> >>> kernel/sys.c::sys_reboot() >>> kernel/drivers/base/power/shutdown.c::device_shutdown() >>> driver specific ->shutdown callback, for ide disks, the path is >>> drivers/ide/ide-disk.c::ide_device_shutdown() >>> drivers/ide/ide-disk.c::ide_cacheflush_p() >>> drivers/ide/ide-disk.c::do_idedisk_flushcache() >>> >>> And, AFAIK, sync() doesn't flush disk caches. >> >> How about umount? >> > > [CC'ing Bartlomiej (Hi!)] > > Hmmm, umount doesn't. I think maybe adding cache flushing to sync and > umount can be helpful. Ehm. So you're saying umount does _not_ flush the disk caches? BUT it will flush the the fs buffers, right? > And one more thing, ide-disk doesn't flush cache when shutting down. It > flushes only when rebooting. How about ide-cs then? When I unregister a drive? -- Steven