From patchwork Sat Feb 9 04:52:56 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Coly Li X-Patchwork-Id: 10804097 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 6AB7C1390 for ; Sat, 9 Feb 2019 04:53:33 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 5B1862DCB3 for ; Sat, 9 Feb 2019 04:53:33 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 4FB162DCDB; Sat, 9 Feb 2019 04:53:33 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id EAA5E2DCB3 for ; Sat, 9 Feb 2019 04:53:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726832AbfBIExc (ORCPT ); Fri, 8 Feb 2019 23:53:32 -0500 Received: from mx2.suse.de ([195.135.220.15]:57618 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726222AbfBIExc (ORCPT ); Fri, 8 Feb 2019 23:53:32 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 162BAAF6F; Sat, 9 Feb 2019 04:53:31 +0000 (UTC) From: Coly Li To: axboe@kernel.dk Cc: linux-bcache@vger.kernel.org, linux-block@vger.kernel.org, Coly Li Subject: [PATCH 04/19] bcache: export backing_dev_uuid via sysfs Date: Sat, 9 Feb 2019 12:52:56 +0800 Message-Id: <20190209045311.15677-5-colyli@suse.de> X-Mailer: git-send-email 2.16.4 In-Reply-To: <20190209045311.15677-1-colyli@suse.de> References: <20190209045311.15677-1-colyli@suse.de> Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP When there are multiple bcache devices, after a reboot the name of bcache devices may change (e.g. current /dev/bcache1 was /dev/bcache0 before reboot). Therefore we need the backing device UUID (sb.uuid) to identify each bcache device. Backing device uuid can be found by program bcache-super-show, but directly exporting backing_dev_uuid by sysfs file /sys/block/bcache/bcache/backing_dev_uuid is a much simpler method. With backing_dev_uuid, and partition uuids from /dev/disk/by-partuuid/, now we can identify each bcache device and its partitions conveniently. Signed-off-by: Coly Li --- drivers/md/bcache/sysfs.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/drivers/md/bcache/sysfs.c b/drivers/md/bcache/sysfs.c index b9166ee027fa..9be27b26d300 100644 --- a/drivers/md/bcache/sysfs.c +++ b/drivers/md/bcache/sysfs.c @@ -68,6 +68,7 @@ read_attribute(btree_written); read_attribute(metadata_written); read_attribute(active_journal_entries); read_attribute(backing_dev_name); +read_attribute(backing_dev_uuid); sysfs_time_stats_attribute(btree_gc, sec, ms); sysfs_time_stats_attribute(btree_split, sec, us); @@ -250,6 +251,13 @@ SHOW(__bch_cached_dev) return strlen(buf); } + if (attr == &sysfs_backing_dev_uuid) { + /* convert binary uuid into 36-byte string plus '\0' */ + snprintf(buf, 36+1, "%pU", dc->sb.uuid); + strcat(buf, "\n"); + return strlen(buf); + } + #undef var return 0; } @@ -460,6 +468,7 @@ static struct attribute *bch_cached_dev_files[] = { &sysfs_bypass_torture_test, #endif &sysfs_backing_dev_name, + &sysfs_backing_dev_uuid, NULL }; KTYPE(bch_cached_dev);