From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wg0-x22f.google.com (mail-wg0-x22f.google.com [IPv6:2a00:1450:400c:c00::22f]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by mail.server123.net (Postfix) with ESMTPS for ; Fri, 8 Aug 2014 15:38:52 +0200 (CEST) Received: by mail-wg0-f47.google.com with SMTP id b13so5594224wgh.18 for ; Fri, 08 Aug 2014 06:38:51 -0700 (PDT) Message-ID: <53E4D2E9.9050005@gmail.com> Date: Fri, 08 Aug 2014 15:38:49 +0200 From: Milan Broz MIME-Version: 1.0 References: <20140808092257.04ccaca7@ncopa-desktop.alpinelinux.org> In-Reply-To: <20140808092257.04ccaca7@ncopa-desktop.alpinelinux.org> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [dm-crypt] luks header on initramfs img fails due to no O_DIRECT support in tmpfs List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Natanael Copa Cc: dm-crypt@saout.de On 08/08/2014 09:22 AM, Natanael Copa wrote: > Hi, > > I found this posting while looking at an issue with cryptsetup-1.6.5 in initramfs: > http://www.saout.de/pipermail/dm-crypt/2014-August/004227.html > > I believe this is same thing as reported here: > http://bugs.alpinelinux.org/issues/3281 > > Seems like the problem is that open(2) does not support O_DIRECT when on tmpfs. > > I don't subscribe to your mailing list but wanted to share anyways. BTW I see patch removing O_DIRECT completely in your distro. As you already mentioned in comment in link above, please do not do this. You are risking data corruption in some situations. Using direct-io should ensure that block device is really updated (And also we really do not want to cache keyslot content in memory.) I know it is not 100% solution but the best way is to report the problem here and then backport upstream fix. (Just use existing device_open() which tries to open device twice, also no need to patch old code which do not fail. See upstream commit, I also added test for tmpfs to not repeat the problem again in future.) Thanks, Milan