From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030545AbdAKP5P (ORCPT ); Wed, 11 Jan 2017 10:57:15 -0500 Received: from mout.kundenserver.de ([212.227.126.131]:52900 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755779AbdAKP5J (ORCPT ); Wed, 11 Jan 2017 10:57:09 -0500 From: Arnd Bergmann To: David Howells Cc: Tina Ruchandani , linux-afs@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] afs: correctly use 64-bit time for UUID Date: Wed, 11 Jan 2017 16:55:58 +0100 Message-ID: <4758856.xip1ncPqxp@wuerfel> User-Agent: KMail/5.1.3 (Linux/4.4.0-34-generic; KDE/5.18.0; x86_64; ; ) In-Reply-To: <6557.1484146040@warthog.procyon.org.uk> References: <2360985.j9pqdKkA3M@wuerfel> <5338.1484142692@warthog.procyon.org.uk> <6557.1484146040@warthog.procyon.org.uk> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-Provags-ID: V03:K0:USnhMPX3zlshWWUqylVpGLGhtACGD49z/S/z+vt+6U/RfTSFWAS AOc4aOBpsH19KL1qUPO4eTN2T0SHgWmOvOcbWlMQCE9zhcRA4jdIOf0uqKcQb60FOh2DKGn mXxARE4TNq6e88+C25YZUZbdwDorzkYsP6cZ2lA+tnUIjl0qOrmO52N685ICSeSh2bXOWGu 9IUxmR955SYc1nCQPLrQg== X-UI-Out-Filterresults: notjunk:1;V01:K0:3qwNSTEx70c=:J77QTd9HxZ4RQR1vYvH42w yquKHYbyL5RCjFfvd/lwtYrJeiBqHlw8dOHZzAByxP6OKLNFD1d0whwu+xfO3rvwtJhtIhMpc XdW1DXAruvL/df+NCtSuBQBHPCLRTri1xduRno8eJq6pPVJCySKPnAX3SbWeW4Ro37fm+rnkL Fv+ABIjZ7qIQfGDPbV0ttAmCyKCwvjWZUD0Pxqxgg76ZK5Ir9DVPisytQDoaCepau2vrQiRk3 vNz9hnNHyrXCU01nMfzlFYSLqap+AnZ9Lob95EzhcbwGbwOsJT7c8c4pfVf/Yh7lB58jRQxBh fVWprUM805lgPphpf1Um+z4KI5Q2AqyFxEEKiIjNcdgzQMv70YI/EdUQzkHdI8ClKDxBIdtFM emCu03tSozYIiIe5fJhHXwENyDOCB/fU45wvnSTjp6pSFyB1RvraYw2kDZeWVgVEWjfKF1inr JzjEt5Kjr8igrytWY+w9QTa68bLxl/FLvKjV+bbX+QzQGXriRTdyR36UfwOShF0ZWEPK+ccqQ NGRWwCKykKSkohAZNPmah3NPCy9wDuJbW4uJgqiI5V5fH7Q522rRB04ieN9xQ0dTZCFmwxQEk xadrmNgDXnipUQG4u/lIch5jGYvUgJZMCxW2+byn/LvXg9Bp60LXGrYP9NcvjVY8ZYCTQQbhX FD/B81cOq8Hztyhobu26WHp5v1iVcEt3qeB7kdhkRBVZrj2oXN911yEXifhZoSQ4CmPxI2wf1 q05seErMrT8RJUEI Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wednesday, January 11, 2017 2:47:20 PM CET David Howells wrote: > Arnd Bergmann wrote: > > > > Is it worth abstracting out in-kernel UUID generation? > > > > Do you mean moving it out of AFS into lib/*.c? I think the 'afs_uuid' > > structure is quite different from other UUID definitions, so that wouldn't > > work. > > afs_uuid is as it is to make it easier to package into the on-wire format, but > I suspect there's no problem with using a completely random UUID instead and > divvying it up the same way. Maybe like this: 8<----7 >>From 9e164f852366750fdd732ae317af9f4a9a04a16e Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Wed, 11 Jan 2017 16:53:13 +0100 Subject: [PATCH] afs: use random UUID AFS uses a time based UUID to identify the host itself. This requires getting a timestamp which is currently done through the getnstimeofday() interface that we want to eventually get rid of. Instead of replacing it with a ktime based interface, this simply removes the entire function and uses generate_random_uuid() instead, which has a v4 ("completely random") uuid instead of the time based one. Signed-off-by: Arnd Bergmann diff --git a/fs/afs/main.c b/fs/afs/main.c index f8188feb03ad..9944770849da 100644 --- a/fs/afs/main.c +++ b/fs/afs/main.c @@ -35,49 +35,6 @@ struct afs_uuid afs_uuid; struct workqueue_struct *afs_wq; /* - * get a client UUID - */ -static int __init afs_get_client_UUID(void) -{ - struct timespec ts; - u64 uuidtime; - u16 clockseq; - int ret; - - /* read the MAC address of one of the external interfaces and construct - * a UUID from it */ - ret = afs_get_MAC_address(afs_uuid.node, sizeof(afs_uuid.node)); - if (ret < 0) - return ret; - - getnstimeofday(&ts); - uuidtime = (u64) ts.tv_sec * 1000 * 1000 * 10; - uuidtime += ts.tv_nsec / 100; - uuidtime += AFS_UUID_TO_UNIX_TIME; - afs_uuid.time_low = uuidtime; - afs_uuid.time_mid = uuidtime >> 32; - afs_uuid.time_hi_and_version = (uuidtime >> 48) & AFS_UUID_TIMEHI_MASK; - afs_uuid.time_hi_and_version |= AFS_UUID_VERSION_TIME; - - get_random_bytes(&clockseq, 2); - afs_uuid.clock_seq_low = clockseq; - afs_uuid.clock_seq_hi_and_reserved = - (clockseq >> 8) & AFS_UUID_CLOCKHI_MASK; - afs_uuid.clock_seq_hi_and_reserved |= AFS_UUID_VARIANT_STD; - - _debug("AFS UUID: %08x-%04x-%04x-%02x%02x-%02x%02x%02x%02x%02x%02x", - afs_uuid.time_low, - afs_uuid.time_mid, - afs_uuid.time_hi_and_version, - afs_uuid.clock_seq_hi_and_reserved, - afs_uuid.clock_seq_low, - afs_uuid.node[0], afs_uuid.node[1], afs_uuid.node[2], - afs_uuid.node[3], afs_uuid.node[4], afs_uuid.node[5]); - - return 0; -} - -/* * initialise the AFS client FS module */ static int __init afs_init(void) @@ -86,9 +43,7 @@ static int __init afs_init(void) printk(KERN_INFO "kAFS: Red Hat AFS client v0.1 registering.\n"); - ret = afs_get_client_UUID(); - if (ret < 0) - return ret; + generate_random_uuid((unsigned char *)&afs_uuid); /* create workqueue */ ret = -ENOMEM;