From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B2B614A0F0E for ; Wed, 2 Sep 2026 14:14:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788358444; cv=none; b=NoyAWqLqUUU2cT5F4CWv1QvFKJQlvVLjQrbsB9RcLI6Ae2hlf1Z/u4YUMnU74zZgjGCzNDYe4IWtAUkA9mPWhT6mWMok73e0imFqP/hz7XdcjtnWVqkenVqgX7lW6v179+tR11xZ1V33LKvRyWwjeAj7muHQL21pJwlRDLLrQSU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788358444; c=relaxed/simple; bh=1FfSBZPQZtbW7koHD2xRJrlHPhzTiEGIlEqllv169f4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=V1Lsif/kFZAAGpqNdUiIT5K2XLk4EFzQrHHNgLytIqdTbYuhJbh4e/XQS6UWISHlzGiSZ5XJHaoboEeVZMAOGF1LA1d9FnxJf49bHYD7Hpt0XpExAbr0d4n6lMXcBirJyECQBiRtNmVQ85sLN1ASbZmbxgWpL1wRMxbztJivNAA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=X5gwgr7X; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="X5gwgr7X" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 89E051F00A3F; Wed, 2 Sep 2026 14:13:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788358442; bh=jGWXYKbYvfrmNeoEiMb4eJUo9HkrH6ZYdGtAKazV/zg=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=X5gwgr7XKNgxgUTcn0kSF7OfbKm6Y5fTqzEaGsIwXEnYa5IEcoEM+yXlqenTfXxyb G7E4bFMqA9ZLpwVCNu8fKZQP68E2WVlvsx53GA9kP65ANWp9TYoNVk9wgVFPFNewX5 yo/CA3QKM4jlKEBdkNlhsJySBNnea3bt8kHz4jdhJZZiJCuaR60R8ksQ5cFazun7kG SZxCYhAnGHQp4r7vGQch+v1UuoY4rxbUrLDJ4pVE83aJvKrxsbW5B+m4nj48y3HAOj u92IAmwO0T+GQWZbScetdF+qm4FKyk3KA4P682V7Ws/uagya/ofDSo1HtiH0XYDIl+ jrmL65+AbfDcg== Date: Wed, 2 Sep 2026 22:13:56 +0800 From: Zorro Lang To: Amir Goldstein Cc: Prabhakar Pujeri , fstests@vger.kernel.org Subject: Re: [PATCH v2] overlay/081: add missing _require_scratch check Message-ID: Mail-Followup-To: Amir Goldstein , Prabhakar Pujeri , fstests@vger.kernel.org References: <20260901132438.759-1-prabhakar.pujeri@dell.com> <20260902073507.5074-1-prabhakar.pujeri@dell.com> Precedence: bulk X-Mailing-List: fstests@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Wed, Sep 02, 2026 at 10:25:57AM +0200, Amir Goldstein wrote: > On Wed, Sep 2, 2026 at 9:35 AM Prabhakar Pujeri > wrote: > > > > On Wed, Sep 02, 2026 at 01:51:08PM +0800, Zorro Lang wrote: > > > As you're fixing this patch, I'm wondering if we need a _require_* helper to > > > make sure the mount options *uuid=null/auto/on* is supported by current system? > > > Due to the comment says "mount options uuid=null/auto/on introduced in kernel > > > v6.6" :) > > > > Thanks for looking. That case is already covered a few lines below the > > change, at the first use of the uuid= option (line 40): > > > > _overlay_scratch_mount_dirs $lowerdir $upperdir $workdir -o uuid=null \ > > 2>/dev/null || \ > > _notrun "Overlayfs does not support unique fsid feature" > > > > overlayfs rejects unknown mount options with EINVAL, so on kernels older > > than v6.6 that probe mount fails and the test skips with the _notrun > > reason instead of failing. The uuid= options are also exercised only by > > this test (it is the sole user of uuid=null/on/auto in the tree), so a > > dedicated _require_* helper would have exactly one call site. Happy to > > factor it out anyway if you would rather have an explicit requirement. > > > > *IF* we would want this, I would not recommend a dedicated require_ > for uuid feature. > > I would recommend teaching _require_scratch_overlay_features/ > _check_overlay_feature to deal with mount options (e.g. uuid=on) > which do not have a module parameter to tune the default. > > So if /sys/module/overlay/parameters/uuid does not exist, instead of > assuming it is not supported, assume that it defaults to off. > > I am not saying this is worth the trouble, which is probably why I took the > easy lane and added the local _notrun condition adhoc in the test. > > Overlayfs enum mount options that can be tested with the generic > features helper: redirect_dir, index, nfs_export, metacopy > > Overlayfs enum mount options that cannot be tested with the > generic features helper because they do not have a corresponding > module param of same name: > uuid, xino, verity, fsync > > verity - has a dedicated helper because it has special conditions. > fsync - test 087 has _require_scratch_shutdown_and_syncfs > which is technically enough to test support for -o volatile > uuid - can benefit from generalization of features helper > xino - all these tests 041, 043, 044, 067, 070, 071 practically open > code the suggested improvement of the generic helper > > So for the uuid test alone it might not be worth it, but unless I am mistaken > for all the xino tests, this would be a nice cleanup/improvement. > > But of course, this should not block this trivial and correct fix patch. Thanks Amir! Sure, I've already applied this patch locally. I just wanted to use this opportunity to bring it up for discussion, as overlayfs is quite a unique filesystem and its features have indeed been growing steadily. I completely agree that having a unified feature check/require helper makes sense. It would definitely make writing future test cases much cleaner and simpler. Any patches in this direction are definitely more than welcome :) Thanks, Zorro > > Thanks, > Amir.