From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cn.fujitsu.com ([59.151.112.132]:41095 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1750966AbaJPJm2 (ORCPT ); Thu, 16 Oct 2014 05:42:28 -0400 Message-ID: <1413452485.7609.7.camel@localhost.localdomain> Subject: Re: [PATCH] btrfs: fix wrong pad for kernelspace arg of btrfs dev stat From: Gui Hecheng To: Stefan Behrens CC: Date: Thu, 16 Oct 2014 17:41:25 +0800 In-Reply-To: <543F8F4B.5080506@giantdisaster.de> References: <1413424419-15237-1-git-send-email-guihc.fnst@cn.fujitsu.com> <543F8F4B.5080506@giantdisaster.de> Content-Type: text/plain; charset="UTF-8" MIME-Version: 1.0 Sender: linux-btrfs-owner@vger.kernel.org List-ID: On Thu, 2014-10-16 at 11:26 +0200, Stefan Behrens wrote: > On Thu, 16 Oct 2014 09:53:37 +0800, Gui Hecheng wrote: > > The @btrfs_ioctl_get_dev_stats fails to pad to 1k as descripted, > > actually it valuates to 1032 bytes. > > The corresponding userspace change follows this change. > > > > Signed-off-by: Gui Hecheng > > --- > > include/uapi/linux/btrfs.h | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/include/uapi/linux/btrfs.h b/include/uapi/linux/btrfs.h > > index 2f47824..fc4e326 100644 > > --- a/include/uapi/linux/btrfs.h > > +++ b/include/uapi/linux/btrfs.h > > @@ -416,7 +416,7 @@ struct btrfs_ioctl_get_dev_stats { > > /* out values: */ > > __u64 values[BTRFS_DEV_STAT_VALUES_MAX]; > > > > - __u64 unused[128 - 2 - BTRFS_DEV_STAT_VALUES_MAX]; /* pad to 1k */ > > + __u64 unused[128 - 3 - BTRFS_DEV_STAT_VALUES_MAX]; /* pad to 1k */ > > You can't change an existing ioctl interface like this and make it > incompatible, the length of the structure is used in _IOWR(). Just > change the comment from "pad to 1k" to "pad to 1032 bytes" instead. Er... yeah, the problem exists, and such a fix seems cost much. Since the related tool itself doesn't influence much, just scratch these two may be a reasonable idea. ^_^ ("pad to 1032 bytes" seems a bit...) > > > }; > > > > #define BTRFS_QUOTA_CTL_ENABLE 1 > > > >