From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 85A911F755F for ; Tue, 17 Dec 2024 17:10:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734455456; cv=none; b=HaNbfjhELIKLkTmLXsdwYDz3Hf/8iKd6Aa7zzYCQJclgNn0WaH3VvJyUp40HrWGROqg4+i7P7cZY7vX7kD+4PFWKNUE1CHlWSzb35fotrjmQBMa3tq4hrd4kVOUgAFSKTJniQD2lAMkxHd+waMOzGunmQsfwg2mjwN+MuQ4Ro+s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734455456; c=relaxed/simple; bh=vfkcBcgodcstZ1cUv+p1zzYVfci6su3nHvhHd5QSlqo=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=kgssKl7zTQ47aYIWduyh0sEku5+w4gDzXIn1DkEjOM9eLezEwgO1du3Fko6P3oPa/VXrGm9vSAgbFzbsOBcGNsblcJpdUcGa2b38uUL08OuxTDlDZIc7+0dtIPuhpM7whk1rcUSNSh3YV7aEiOKpjZJLiOrDIs2/hQGOjWXb03w= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=diq1e8TQ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="diq1e8TQ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 48311C4CEDF; Tue, 17 Dec 2024 17:10:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1734455456; bh=vfkcBcgodcstZ1cUv+p1zzYVfci6su3nHvhHd5QSlqo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=diq1e8TQ+UKN5Kl5gveIMb/vj643Qmv2v+cOUNXjR54OUINoq74DkVowqSIcGL7yU GQoVSN98tp5fiXjCrglT6DFMlPoeEYXUGwTF86y4oG97z9tgXhYkk3qSte9xVF+1fe VScMlqvsBJjugnG82IVb8mRnt8zV/EBBtxjKpM9EtH0KLMymrhS3rrnbyRHUZ5jSKX pnNE29HqwAh0qOjqJhqHjtufx2G7brZR43NImydP+sEiRZxNt3YfJujl5KDhXalgj3 0BdWa6Q1WHrMYb+hA1PJ0RTgI6lGGi5WYvbxzGSB2MIjNvrSW5H6VhXDiMue4l5ruw LEImAWqrabqcg== Date: Tue, 17 Dec 2024 09:10:55 -0800 From: "Darrick J. Wong" To: Christoph Hellwig Cc: Carlos Maiolino , Hans Holmberg , linux-xfs@vger.kernel.org Subject: Re: [PATCH 36/43] xfs: disable reflink for zoned file systems Message-ID: <20241217171055.GJ6174@frogsfrogsfrogs> References: <20241211085636.1380516-1-hch@lst.de> <20241211085636.1380516-37-hch@lst.de> <20241213231247.GG6678@frogsfrogsfrogs> <20241215062654.GH10855@lst.de> Precedence: bulk X-Mailing-List: linux-xfs@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: <20241215062654.GH10855@lst.de> On Sun, Dec 15, 2024 at 07:26:54AM +0100, Christoph Hellwig wrote: > On Fri, Dec 13, 2024 at 03:12:47PM -0800, Darrick J. Wong wrote: > > On Wed, Dec 11, 2024 at 09:55:01AM +0100, Christoph Hellwig wrote: > > > While the zoned on-disk format supports reflinks, the GC code currently > > > always unshares reflinks when moving blocks to new zones, thus making the > > > feature unusuable. Disable reflinks until the GC code is refcount aware. > > > > This goes back to the question I had in the gc patch -- can we let > > userspace do its own reflink-aware freespace copygc, and only use the > > in-kernel gc if userspace doesn't respond fast enough? I imagine > > someone will want to share used blocks on zoned storage at some point. > > I'm pretty sure we could, if we're willing to deal with worse decision > making, worse performance and potential for deadlocks while dealing with > a bigger and more complicated code base. But why? Mostly intellectual curiosity on my part about self-reorganizing filesystems. The zonegc you've already written is good enough for now, though the no-reflink requirement feels a bit onerous. But hey, it's not like I have numbers showing that a userspace copy-dedupe gc strategy is any better, so I'll not hold up this whole series on account of that. --D