From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f51.google.com ([209.85.220.51]:35686 "EHLO mail-pa0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752144AbbETDEi (ORCPT ); Tue, 19 May 2015 23:04:38 -0400 Received: by pacwv17 with SMTP id wv17so49748798pac.2 for ; Tue, 19 May 2015 20:04:37 -0700 (PDT) Message-ID: <555BF9BF.90909@linaro.org> Date: Wed, 20 May 2015 11:04:31 +0800 From: Alex Shi MIME-Version: 1.0 To: Jan Kara CC: Dmitry Monakhov , Theodore Ts'o , Linaro Kernel , stable@vger.kernel.org Subject: Re: a old issue of ext4 on lts 3.10 References: <5554B3E3.6090407@linaro.org> <87bnhmrj5c.fsf@openvz.org> <5558B198.4040609@linaro.org> <20150518064146.GC26351@quack.suse.cz> In-Reply-To: <20150518064146.GC26351@quack.suse.cz> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: stable-owner@vger.kernel.org List-ID: > Because the disk driver may be computing checksum of the data before > submitting it to the disk and if you change the data after the checksum is > computed but before the DMA transfer is done, the checksum will not match. Thanks again! > >> BTW, >> how to know if my disk support data integrity. My harddisk spec said it >> has this feature, but my linux kernel with integrity supported don't >> have /sys/block/sdx/integrity. > The feature you are looking for is called DIF/DIX IIRC and not many disks > support it. Oh, that's bad. Looks in block layer will merge or find out the shared checksum type. So if 2 kind of different disk in system without share checksum type. that could cause each of disk lose data integrity checking?