From patchwork Tue Sep 28 12:37:30 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nikolay Borisov X-Patchwork-Id: 12522437 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C64CDC433EF for ; Tue, 28 Sep 2021 12:37:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A446F61159 for ; Tue, 28 Sep 2021 12:37:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240555AbhI1MjP (ORCPT ); Tue, 28 Sep 2021 08:39:15 -0400 Received: from smtp-out2.suse.de ([195.135.220.29]:54910 "EHLO smtp-out2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240488AbhI1MjP (ORCPT ); Tue, 28 Sep 2021 08:39:15 -0400 Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id 67CF220213; Tue, 28 Sep 2021 12:37:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1632832652; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=/2Y1khj2rbBB6FR0MyshfdnpoQEpNPcfGag2w1vcBEU=; b=DUpl9mgNG7P0N9YGP1aGOTTIQveRV6kfoZj0mWCvou+dTqSHSE9asgp8qu5OAtNTLrS7aZ qPpC7Pdy8c4OWevdoWQxZu1bJ/DVUIm2Lj/D540puvpFIHCXteertRPFJY+NZykgYUFzGg 2+PvIGiGJaXCmD40UobVPXJfSlvp7x0= Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 399EA13A82; Tue, 28 Sep 2021 12:37:32 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id yHStC4wMU2GLCwAAMHmgww (envelope-from ); Tue, 28 Sep 2021 12:37:32 +0000 From: Nikolay Borisov To: linux-btrfs@vger.kernel.org Cc: Nikolay Borisov Subject: [PATCH 2/2] btrfs-progs: Ignore path devices during scan - static build support Date: Tue, 28 Sep 2021 15:37:30 +0300 Message-Id: <20210928123730.393551-2-nborisov@suse.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210928123730.393551-1-nborisov@suse.com> References: <20210928123730.393551-1-nborisov@suse.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org Since libudev doesn't provide a static version of the library for static build btrfs-progs will have to provide manual fallback. THis change does exactly this by parsing the udev database files hosted /run/udev/data/. Under that directory every block device should have a file with the following name: bMAJ:MIN. So implement the bare minimum code necessary to parse this file and search for the presence of DM_MULTIPATH_DEVICE_PATH udev attribute. This could likely be racy since access to the udev database is done outside of libudev but that's the best that can be done when implementing this manually. To reduce duplication of code also factor out the specifics of is_path_device to __is_path_device which will contain the appropriate implementation according to the build mode (i.e relying on libudev in case of normal build or manual fall back code in case of static build) or simply utilize the old logic (in case of a normal build and libudev missing). Signed-off-by: Nikolay Borisov --- common/device-scan.c | 66 ++++++++++++++++++++++++++++++++++++++------ 1 file changed, 57 insertions(+), 9 deletions(-) diff --git a/common/device-scan.c b/common/device-scan.c index 2ed0e34d3664..9779dd1aedf3 100644 --- a/common/device-scan.c +++ b/common/device-scan.c @@ -29,6 +29,7 @@ #include #include #include +#include #ifdef HAVE_LIBUDEV #include #include @@ -372,23 +373,56 @@ void free_seen_fsid(struct seen_fsid *seen_fsid_hash[]) } } -#ifdef HAVE_LIBUDEV -static bool is_path_device(char *device_path) +#ifdef STATIC_BUILD +static bool __is_path_device(dev_t dev) +{ + FILE *file; + char *line = NULL; + size_t len = 0; + ssize_t nread; + bool ret = false; + int ret2; + struct stat dev_stat; + char path[100]; + + ret2 = snprintf(path, 100, "/run/udev/data/b%u:%u", major(dev_stat.st_rdev), + minor(dev_stat.st_rdev)); + + if (ret2 >= 100 || ret2 < 0) + return false; + + file = fopen(path, "r"); + if (file == NULL) + return false; + + while ((nread = getline(&line, &len, file)) != -1) { + if (strstr(line, "DM_MULTIPATH_DEVICE_PATH=1")) { + ret = true; + printf("found dm multipath line: %s\n", line); + break; + } + } + + if (line) + free(line); + + fclose(file); + + return ret; +} +#elif defined(HAVE_LIBUDEV) +static bool __is_path_device(dev_t device) { struct udev *udev = NULL; struct udev_device *dev = NULL; - struct stat dev_stat; const char *val; bool ret = false; - if (stat(device_path, &dev_stat) < 0) - return false; - udev = udev_new(); if (!udev) goto out; - dev = udev_device_new_from_devnum(udev, 'b', dev_stat.st_rdev); + dev = udev_device_new_from_devnum(udev, 'b', device); if (!dev) goto out; @@ -401,8 +435,24 @@ static bool is_path_device(char *device_path) return ret; } +#else +static bool __is_path_device(dev_t device) +{ + return false; +} #endif +static bool is_path_device(char *device_path) +{ + struct stat dev_stat; + + if (stat(device_path, &dev_stat) < 0) + return false; + + return __is_path_device(dev_stat.st_rdev); + +} + int btrfs_scan_devices(int verbose) { int fd = -1; @@ -433,10 +483,8 @@ int btrfs_scan_devices(int verbose) /* if we are here its definitely a btrfs disk*/ strncpy_null(path, blkid_dev_devname(dev)); -#ifdef HAVE_LIBUDEV if (is_path_device(path)) continue; -#endif fd = open(path, O_RDONLY); if (fd < 0) {