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 7F1CE352F95; Wed, 4 Mar 2026 13:28:17 +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=1772630898; cv=none; b=MaFjLMHqUHRVwMKPm32KE+U0YQfQ6LRPV46VjvVwiVnL0wYsQXWKMHi8RYVZEVwQz5h/1kIy5Wx5fY/KMfItSfIvuB6bw/ZoHRkUKEQRAadLNePx3UJARJntOYWEm2NqcH8lYz6VY58cOwcgXqbhjyDJn1qY6gq4ukcS81ck71U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772630898; c=relaxed/simple; bh=SVOIZ+ZQm6umt0dgDvXK33VRlElbT4kLC7JaxnoN+0A=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=s/6Urr3Ti3NM40Nf1jae4BhUtxzqT4D1gjH+y82TlVd4D/X17JM9HbBJ1IXHGWGobpasFq4O3igH4xvzqntsMdZL8hOWocA3PyOizOGY6yWipzgw1pw6+TrGLWJK5kUWqHuSR6RW5YkBXE8QwFZAdkSc9rzk3fLn1ecTPaXQsHQ= 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=B9wXMS43; 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="B9wXMS43" 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=u4tDNrsfmkN1jCpPN9zt23p6IPrJrTgXec+c+UsxUz0=; b=B9wXMS43baSn2tXBwUe7m8IBeu 5IXVC89bWglrmU2qDRUbibxmLfgTXUoaasP32IEISDvcx05r3AOf7sDiKMsdl5kUXYOph2nLd5tTG buu4i4HnIELFf30YTYO6QHIUYLpKA9M8qBWH3s752P9SbJQ83MsgEQS3BJoyXZtz8YxRtQN5YCGF/ J0JOLbLCppR4AenYRt+btPFy189yONESl5VvZrUzk6eTxvjfEXWqHziyWHs8XateJ07X5qW0sylRH nhweam1Y8mQHwfbYpk8OjEId4m0R/rufevmN6Sh6k1UCVa/V0W/yAu5Rm45XDrQ/NFY9y0TD8wWS+ pXmadYAQ==; Received: from hch by bombadil.infradead.org with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1vxmGv-0000000HFKG-0F3o; Wed, 04 Mar 2026 13:28:17 +0000 Date: Wed, 4 Mar 2026 05:28:17 -0800 From: Christoph Hellwig To: Anand Jain Cc: 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: Precedence: bulk X-Mailing-List: linux-btrfs@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: X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html On Thu, Feb 26, 2026 at 10:23:32PM +0800, Anand Jain wrote: > This series resolves the tradeoff by aligning btrfs and ext4 behaviour > with XFS: f_fsid incorporates device identity (devt) to remain unique > across clones, while s_uuid is preserved consistently matching the on-disk > uuid. While I like fixing this up, switching the f_fsid construction to a different method might break things. Is there a way to only change it for cloned file systems to reduce the surface of this change? > Patches > ------- > Patch 1/3: btrfs: fix f_fsid to include rootid and devt > Patch 2/3: btrfs: fix s_uuid to be stable across mounts for cloned filesystems > Patch 3/3: ext4: fix f_fsid to use devt instead of s_uuid I don't really see that patch 3 in my inbox on linux-btrfs.