From mboxrd@z Thu Jan 1 00:00:00 1970 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 picard.linux.it (picard.linux.it [213.254.12.146]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id AA889C433F5 for ; Mon, 10 Oct 2022 13:13:07 +0000 (UTC) Received: from picard.linux.it (localhost [IPv6:::1]) by picard.linux.it (Postfix) with ESMTP id D5E103CAE8C for ; Mon, 10 Oct 2022 15:13:05 +0200 (CEST) Received: from in-6.smtp.seeweb.it (in-6.smtp.seeweb.it [217.194.8.6]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-384)) (No client certificate requested) by picard.linux.it (Postfix) with ESMTPS id 516F73C00D5 for ; Mon, 10 Oct 2022 15:12:56 +0200 (CEST) Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by in-6.smtp.seeweb.it (Postfix) with ESMTPS id 7B31B14002B6 for ; Mon, 10 Oct 2022 15:12:55 +0200 (CEST) Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out1.suse.de (Postfix) with ESMTP id E61B2219A6; Mon, 10 Oct 2022 13:12:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1665407574; h=from:from:reply-to:reply-to:date:date:message-id:message-id:to:to: cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=OSHBFwMAv/9NubotoMediHmVjoHhqK1Nn1NWc1gYHXw=; b=AHWQv91CDxR/TVTRubeEPPSRROkjnBBeRaHKPrgP3qzydH21QSYcxp8oubOpkomU9UMCYb yoyZq6lNBaiLL4rLc74dVmHTuFvNa3zo3N3DAHeiqpKDjF3DPLlHwTmFQkUYKrzTGzG1Yz mpd4v+fiuL/abJnCO3oPUjQjXxEIIu8= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1665407574; h=from:from:reply-to:reply-to:date:date:message-id:message-id:to:to: cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=OSHBFwMAv/9NubotoMediHmVjoHhqK1Nn1NWc1gYHXw=; b=X8O3h650npmjF+H1Hu2NozQ9cv3WX4znIFJW7y4h6jRYmh6uLoUqij7mYzmKpr9YidQYBc 8bg87Ps4ntFk2+Bw== Received: from g78 (unknown [10.100.228.202]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by relay2.suse.de (Postfix) with ESMTPS id 3B3F92C141; Mon, 10 Oct 2022 13:12:54 +0000 (UTC) References: <87fsj7onim.fsf@suse.de> <87bktvokfl.fsf@suse.de> User-agent: mu4e 1.6.10; emacs 28.1 From: Richard Palethorpe To: Jan Stancek Date: Mon, 10 Oct 2022 13:51:52 +0100 In-reply-to: Message-ID: <875ygrakkr.fsf@suse.de> MIME-Version: 1.0 X-Virus-Scanned: clamav-milter 0.102.4 at in-6.smtp.seeweb.it X-Virus-Status: Clean Subject: Re: [LTP] [PATCH] tst_find_backing_dev: fix logic in matching mount point X-BeenThere: ltp@lists.linux.it X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux Test Project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: rpalethorpe@suse.de Cc: LTP List Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: ltp-bounces+ltp=archiver.kernel.org@lists.linux.it Sender: "ltp" Hello, Jan Stancek writes: > On Mon, Jul 11, 2022 at 3:21 PM Richard Palethorpe wrote: >> >> Hello, >> >> Jan Stancek writes: >> >> > On Mon, Jul 11, 2022 at 2:13 PM Richard Palethorpe wrote: >> >> >> >> Hello, >> >> >> >> Jan Stancek writes: >> >> >> >> > If backing dev is btrfs root device, then starting best_match_len >> >> > from 1 creates an issue, because root (/) is never matched. >> >> > Also we should check that entire mount point string is present in >> >> > path we are matching against. >> >> > >> >> > In case there's error also dump /proc/self/mountinfo before tst_brk. >> >> > >> >> > This fixes test with following partition layout (TMPDIR is on /): >> >> > # cat /proc/self/mountinfo | grep btrfs >> >> > 59 1 0:29 /root / rw,relatime shared:1 - btrfs /dev/dasda2 rw,seclabel,compress=zstd:1,ssd,space_cache=v2,subvolid=257,subvol=/root >> >> > 93 59 0:29 /home /home rw,relatime shared:47 - btrfs /dev/dasda2 rw,seclabel,compress=zstd:1,ssd,space_cache=v2,subvolid=256,subvol=/home >> >> > >> >> > Signed-off-by: Jan Stancek >> >> > --- >> >> > lib/tst_device.c | 17 ++++++++++++----- >> >> > 1 file changed, 12 insertions(+), 5 deletions(-) >> >> > >> >> > diff --git a/lib/tst_device.c b/lib/tst_device.c >> >> > index c34cbe6d1f56..414bf0eea816 100644 >> >> > --- a/lib/tst_device.c >> >> > +++ b/lib/tst_device.c >> >> > @@ -506,12 +506,17 @@ unsigned long tst_dev_bytes_written(const char *dev) >> >> > return dev_bytes_written; >> >> > } >> >> > >> >> > -static int count_match_len(const char *first, const char *second) >> >> > +static int str_starts_with(const char *str, const char *prefix) >> >> > { >> >> > int len = 0; >> >> > >> >> > - while (*first && *first++ == *second++) >> >> > + while (*prefix) { >> >> > + if (!*str) >> >> > + return 0; >> >> > + if (*str++ != *prefix++) >> >> > + return 0; >> >> > len++; >> >> > + } >> >> >> >> I'm not sure this is better than the original. It's a seperate cleanup >> >> in any case. >> > >> > The difference is that partial matches now returns 0. Previously it did not, >> > it only counted number of matching characters. So for example ("/foobar" "/foo") >> > appeared as better match than ("/foobar", "/") >> >> Ah, sorry. >> >> > >> >> >> >> > >> >> > return len; >> >> > } >> >> > @@ -524,7 +529,7 @@ void tst_find_backing_dev(const char *path, char *dev) >> >> > char *pre = NULL; >> >> > char *next = NULL; >> >> > unsigned int dev_major, dev_minor, line_mjr, line_mnr; >> >> > - unsigned int len, best_match_len = 1; >> >> > + unsigned int len, best_match_len = 0; >> >> > char mnt_point[PATH_MAX]; >> >> > >> >> > if (stat(path, &buf) < 0) >> >> > @@ -550,7 +555,7 @@ void tst_find_backing_dev(const char *path, char *dev) >> >> > break; >> >> > } >> >> > >> >> > - len = count_match_len(path, mnt_point); >> >> > + len = str_starts_with(path, mnt_point); >> >> > if (len > best_match_len) { >> >> > strcpy(dev, pre); >> >> > best_match_len = len; >> >> > @@ -559,8 +564,10 @@ void tst_find_backing_dev(const char *path, char *dev) >> >> > >> >> > SAFE_FCLOSE(NULL, file); >> >> > >> >> > - if (!*dev) >> >> > + if (!*dev) { >> >> > + tst_system("cat /proc/self/mountinfo"); >> >> > tst_brkm(TBROK, NULL, "Cannot find block device for %s", path); >> >> > + } >> >> > >> >> > if (stat(dev, &buf) < 0) >> >> > tst_brkm(TWARN | TERRNO, NULL, "stat(%s) failed", dev); >> >> > -- >> >> > 2.27.0 >> >> >> >> Makes sense. However I suspect this function can be replaced with the >> >> standard library method used in tst_stat_mount_dev. I didn't try this >> >> before because I'm not sure why it scans mountinfo instead of mounts. >> > >> > /proc/self/mounts doesn't contain major/minor numbers, which is primarily what >> > tst_find_backing_dev is using. >> >> Does anyone know a situation where checking the mount path doesn't work? > > You could mount multiple times to same mount path, which would make it harder > to find the right one. > >> It seems like we are just checking the device numbers first for >> historical reasons and not because it is necessary. > > Device numbers seem slightly less ambiguous. I'm still not entirely sure about this, but if you want to merge then please go ahead. Acked-by: Richard Palethorpe > >> >> I haven't seen any failure reports for io_control01 which only checks >> the path with tst_stat_mount_dev. However this test only runs if you >> have CG v2 enabled by default. >> >> > >> >> >> >> >> >> -- >> >> Thank you, >> >> Richard. >> >> >> >> >> -- >> Thank you, >> Richard. >> -- Thank you, Richard. -- Mailing list info: https://lists.linux.it/listinfo/ltp