From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 8A1A73822BC; Thu, 5 Mar 2026 14:21:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.133 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772720490; cv=none; b=E4t15HOVC1QuSvW0MzC6THaK3ur98vA+1JK3TuwEwLuiHDMiUCQrLPGoWL3k2CxParPM0bliu2FnRiJTEUCVu8JoA0Xzyhabrn11VchNojG4r/pjJJV1cFH92WS9nYrXspBn7uUU0u09R39plKVljyd5E7Huh40/MJWuMBW0sdI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772720490; c=relaxed/simple; bh=AwUGOjlCKVPG0f6btFVnEpBsW2KnOyBY55Vv2znOHfI=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=A75DWkHamaRzV2uzlBgV43kVSdcAiQVqvt+UHZHAdsdgo3GBeOMxIAOGZ/weS6IwPbSsUMlGoDCLfzCWy/ES0lKsqiNhweAaoFsZhLhHYq1MxF2zEQB8TqIXTrlzdpCMDaM3Nfm/GsQe/0pdkL8LZSaP/AHon/jqCaLBVzRePPc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=L9qEq08u; arc=none smtp.client-ip=198.137.202.133 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="L9qEq08u" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=AwUGOjlCKVPG0f6btFVnEpBsW2KnOyBY55Vv2znOHfI=; b=L9qEq08u5Rq/AUyQ1vSUnzAaO6 Isj4VW9IVAshGV1Fwb7ftl9fxwTFxgBcrtG+1p8WWfGyaXLM3o30ZrsQN/ocUHPmGoO0JK2slbAZT lCh1sC0nsQPratBPpbR3rrDq+DyDsPWLcL8Ug3osebXucwp2w1UTscEarmt81r3KGegn+xd2YUV4t 1b2rV3M/N6FLVTorKCphK25SZHUAglJu4Nj2M+LZWmGI4/tzmaoMEqpVPVJ+3axUB4DS92mxWqVfC rcJfJN5PBBi7IWQdJ3HlIg5T76qM3IDCE/VRoF1rUSCEcPWJHjw6k6eM0Ob/dQHyik6dUPCHaGPNy 14WFBObA==; Received: from hch by bombadil.infradead.org with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1vy9Zx-00000001whB-07r0; Thu, 05 Mar 2026 14:21:29 +0000 Date: Thu, 5 Mar 2026 06:21:29 -0800 From: Christoph Hellwig To: Anand Jain Cc: Christoph Hellwig , Anand Jain , linux-btrfs@vger.kernel.org, linux-ext4@vger.kernel.org Subject: Re: [PATCH 0/3] fix s_uuid and f_fsid consistency for cloned filesystems Message-ID: References: <9078e07d-5997-41f3-9991-c1f6975c768b@gmail.com> Precedence: bulk X-Mailing-List: linux-ext4@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <9078e07d-5997-41f3-9991-c1f6975c768b@gmail.com> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html On Thu, Mar 05, 2026 at 05:32:36PM +0800, Anand Jain wrote: > The problem is that we won't know which filesystem is the original > and which is the clone. Generally, the first one mounted is treated > as the original and the following one as the clone. However, f_fsid > should remain consistent regardless of mount order, at least for > the duration that the block device is connected (or until a > system reboot). Then maybe we need to make the new sane behavior dependent on a feature flag so that only newly created file systems use it?