From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cust-95-128-94-82.breedbanddelft.nl ([95.128.94.82]:50784 "EHLO cust-95-128-94-82.breedbanddelft.nl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727311AbeIEQhn (ORCPT ); Wed, 5 Sep 2018 12:37:43 -0400 Date: Wed, 5 Sep 2018 14:07:46 +0200 From: Rogier Wolff To: Jeff Layton Cc: =?utf-8?B?54Sm5pmT5Yas?= , bfields@fieldses.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: POSIX violation by writeback error Message-ID: <20180905120745.GP17123@BitWizard.nl> References: <82ffc434137c2ca47a8edefbe7007f5cbecd1cca.camel@redhat.com> <20180904161203.GD17478@fieldses.org> <20180904162348.GN17123@BitWizard.nl> <20180904185411.GA22166@fieldses.org> <09ba078797a1327713e5c2d3111641246451c06e.camel@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <09ba078797a1327713e5c2d3111641246451c06e.camel@redhat.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Wed, Sep 05, 2018 at 06:55:15AM -0400, Jeff Layton wrote: > There is no requirement for a filesystem to flush data on close(). And you can't start doing things like that. In some weird cases, you might have an application open-write-close files at a much higher rate than what a harddisk can handle. And this has worked for years because the kernel caches stuff from inodes and data-blocks. If you suddenly write stuff to harddisk at 10ms for each seek between inode area and data-area... You end up limited to about 50 of these open-write-close cycles per second. My home system is now able make/write/close about 100000 files per second. assurancetourix:~/testfiles> time ../a.out 100000 000 0.103u 0.999s 0:01.10 99.0% 0+0k 0+800000io 0pf+0w (The test program was accessing arguments beyond the end-of-arguments, An extra argument for this one time program was easier than open/fix/recompile). Roger. -- ** R.E.Wolff@BitWizard.nl ** http://www.BitWizard.nl/ ** +31-15-2600998 ** ** Delftechpark 26 2628 XH Delft, The Netherlands. KVK: 27239233 ** *-- BitWizard writes Linux device drivers for any device you may have! --* The plan was simple, like my brother-in-law Phil. But unlike Phil, this plan just might work.