From patchwork Thu Jun 24 03:19:57 2010 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ryan Harper X-Patchwork-Id: 56738 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [199.232.76.165]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 6BCD9B6F17 for ; Thu, 24 Jun 2010 13:22:54 +1000 (EST) Received: from localhost ([127.0.0.1]:44527 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1ORd1e-00044B-C4 for incoming@patchwork.ozlabs.org; Wed, 23 Jun 2010 23:22:50 -0400 Received: from [140.186.70.92] (port=57388 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1ORcz3-0002jl-VG for qemu-devel@nongnu.org; Wed, 23 Jun 2010 23:20:11 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.69) (envelope-from ) id 1ORcz1-0000Xg-AC for qemu-devel@nongnu.org; Wed, 23 Jun 2010 23:20:09 -0400 Received: from e3.ny.us.ibm.com ([32.97.182.143]:34651) by eggs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1ORcz1-0000XX-7v for qemu-devel@nongnu.org; Wed, 23 Jun 2010 23:20:07 -0400 Received: from d01relay06.pok.ibm.com (d01relay06.pok.ibm.com [9.56.227.116]) by e3.ny.us.ibm.com (8.14.4/8.13.1) with ESMTP id o5O36IvW029717 for ; Wed, 23 Jun 2010 23:06:18 -0400 Received: from d01av02.pok.ibm.com (d01av02.pok.ibm.com [9.56.224.216]) by d01relay06.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id o5O3K3HO1511522 for ; Wed, 23 Jun 2010 23:20:03 -0400 Received: from d01av02.pok.ibm.com (loopback [127.0.0.1]) by d01av02.pok.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id o5O3K2nA002074 for ; Thu, 24 Jun 2010 00:20:03 -0300 Received: from localhost.localdomain (sig-9-65-88-241.mts.ibm.com [9.65.88.241]) by d01av02.pok.ibm.com (8.14.4/8.13.1/NCO v10.0 AVin) with ESMTP id o5O3K0BI001875; Thu, 24 Jun 2010 00:20:02 -0300 From: Ryan Harper To: virtualization@lists.linux-foundation.org Date: Wed, 23 Jun 2010 22:19:57 -0500 Message-Id: <1277349598-24559-2-git-send-email-ryanh@us.ibm.com> X-Mailer: git-send-email 1.6.3.3 In-Reply-To: <1277349598-24559-1-git-send-email-ryanh@us.ibm.com> References: <1277349598-24559-1-git-send-email-ryanh@us.ibm.com> X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6, seldom 2.4 (older, 4) Cc: john cooper , Rusty Russell , qemu-devel@nongnu.org, kvm@vger.kernel.org, Ryan Harper Subject: [Qemu-devel] [PATCH 1/2] v2 Add 'serial' attribute to virtio-blk devices X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Create a new attribute for virtio-blk devices that will fetch the serial number of the block device. This attribute can be used by udev to create disk/by-id symlinks for devices that don't have a UUID (filesystem) associated with them. ATA_IDENTIFY strings are special in that they can be up to 20 chars long and aren't required to be nul-terminated. The buffer is also zero-padded meaning that if the serial is 19 chars or less that we get a nul-terminated string. When copying this value into a string buffer, we must be careful to copy up to the nul (if it present) and only 20 if it is longer and not to attempt to nul terminate; this isn't needed. Changes since v1: - Added BUILD_BUG_ON() for PAGE_SIZE check - Removed min() since BUILD_BUG_ON() handles the check - Replaced serial_sysfs() by copying id directly to buffer Signed-off-by: Ryan Harper Signed-off-by: john cooper --- drivers/block/virtio_blk.c | 28 ++++++++++++++++++++++++++++ 1 files changed, 28 insertions(+), 0 deletions(-) diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c index 258bc2a..34411ff 100644 --- a/drivers/block/virtio_blk.c +++ b/drivers/block/virtio_blk.c @@ -281,6 +281,27 @@ static int index_to_minor(int index) return index << PART_BITS; } +static ssize_t virtblk_serial_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct gendisk *disk = dev_to_disk(dev); + int err; + + /* sysfs gives us a PAGE_SIZE buffer */ + BUILD_BUG_ON(PAGE_SIZE < VIRTIO_BLK_ID_BYTES); + + buf[VIRTIO_BLK_ID_BYTES] = '\0'; + err = virtblk_get_id(disk, buf); + if (!err) + return strlen(buf); + + if (err == -EIO) /* Unsupported? Make it empty. */ + return 0; + + return err; +} +DEVICE_ATTR(serial, S_IRUGO, virtblk_serial_show, NULL); + static int __devinit virtblk_probe(struct virtio_device *vdev) { struct virtio_blk *vblk; @@ -445,8 +466,15 @@ static int __devinit virtblk_probe(struct virtio_device *vdev) add_disk(vblk->disk); + err = device_create_file(disk_to_dev(vblk->disk), &dev_attr_serial); + if (err) + goto out_del_disk; + return 0; +out_del_disk: + del_gendisk(vblk->disk); + blk_cleanup_queue(vblk->disk->queue); out_put_disk: put_disk(vblk->disk); out_mempool: