From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pierre Beck Subject: Re: Loosing transactions Date: Tue, 29 Jan 2013 21:16:02 +0100 Message-ID: <51082E02.7000908@pierre-beck.de> References: <51004490.704@pierre-beck.de> <20130124233559.GO26407@google.com> <51068F01.9060000@pierre-beck.de> <20130129190133.GL26407@google.com> <20130129190942.GM26407@google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20130129190942.GM26407-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org> Sender: linux-bcache-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Kent Overstreet Cc: linux-bcache-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-bcache@vger.kernel.org Am 29.01.2013 20:09, schrieb Kent Overstreet: > I lied, that idea turned out to be wrong. > > Though - data=journal isn't that commonly used, an ext4 bug is an > outside possibility (if it was assuming the pre 2.6.38 semantics of > barriers that could cause this). Could you test with data=ordered and > tell me what happens? > Sorry I didn't state that clearly. The ext4 data=journal test was for comparison only. All bcache tests were done with defaults, which is data=ordered. # mkfs.ext4 -K -b 4096 # mount -o noatime Disabling all hardware caches with hdparm AND putting bcache in writethrough mode made it pass the test, btw., with severe performance loss of course. What's really alarming is that bcache in writeback with hw caches deactivated still loses transactions. This points to the journal logic. Maybe the last element of the journal is simply not iterated? Greetings, Pierre Beck