From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out30-124.freemail.mail.aliyun.com (out30-124.freemail.mail.aliyun.com [115.124.30.124]) (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 481E51C8617 for ; Tue, 8 Apr 2025 09:11:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744103487; cv=none; b=JHWbKrzrx/LvIIl151rZu/+wm2ijFxNKDvpwJTlJ/vcdFjeXHx8l7xdFHADVW4KrMzWTM5Jgqx9QEfcWwmBI+op4V2dpt3JbtsPNWk74TUjPEBhgWbcLdcBU5yX27Gq28FmINJMXS3jTTFsWVRytvoxZHdsJ7DKBx3dmVt4hs9s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744103487; c=relaxed/simple; bh=jVy/MK7bBVX1gRdZQ076RoaH0+XfycZXX7LUcm+1hks=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=tyU+fcb0HEXTpXuQUvi8vwLh1qQisXv+s5SxrL1z5AoH5lmbOAGRIC0wSnmTLL+iv85uEG0+iiJ3zUuxFaHwxpjJlmQm50pzEOiVJm1LHNKAf/O2Hm6084XZutSh1FaUEEY6HAEWw824fIy9XbAfDkN8H0I8j7HxEWq9v72d58Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com; spf=pass smtp.mailfrom=linux.alibaba.com; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b=k+Egiz57; arc=none smtp.client-ip=115.124.30.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b="k+Egiz57" DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1744103476; h=Message-ID:Date:MIME-Version:Subject:To:From:Content-Type; bh=luGcT9UL4O/HTTEZuavQB4JaVAyjvuyVqOeWlRcydM8=; b=k+Egiz57IDtOfhAc1xrMIa3xnKNR5yXobnbao9sO8ZJNmilJJD+oOtZ0D0KFFqT/xv0tSlHkNauU/T07WtDh4fhZRorlyL5qD1fFh10/Vyr5H4e3WNFjRR4EWlg9MXWaNWAy9Z30P8uh6t5yY74LccwtRafR7t6/xMIdswgh8s8= Received: from 30.74.129.179(mailfrom:hsiangkao@linux.alibaba.com fp:SMTPD_---0WWEd0mn_1744103474 cluster:ay36) by smtp.aliyun-inc.com; Tue, 08 Apr 2025 17:11:15 +0800 Message-ID: <98585dd8-d0b6-4000-b46d-a08c64eae44d@linux.alibaba.com> Date: Tue, 8 Apr 2025 17:11:14 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 2/2] erofs: add 'offset' mount option for file-backed & bdev-based mounts To: Karel Zak Cc: Sheng Yong , xiang@kernel.org, chao@kernel.org, zbestahu@gmail.com, jefflexu@linux.alibaba.com, dhavale@google.com, linux-erofs@lists.ozlabs.org, linux-kernel@vger.kernel.org, Sheng Yong , Wang Shuai References: <20250407110551.1538457-1-shengyong1@xiaomi.com> <20250407110551.1538457-2-shengyong1@xiaomi.com> <7nupludayogog6jylmwnxwel4zlvfxeozzcg5qkf5g5a5fpt7g@3bgvpbqfuxxa> From: Gao Xiang In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 2025/4/8 16:46, Karel Zak wrote: > On Mon, Apr 07, 2025 at 11:49:31PM +0800, Gao Xiang wrote: >> On 2025/4/7 19:40, Karel Zak wrote: >>> We can improve it in libmount and add any if-erofs hack there, but my >>> suggestion is to select a better name for the mount option. For >>> example, erofsoff=, erostart=, fsoffset=, start=, or similar. >> >> Thanks for your suggestion! >> >> it's somewhat weird to use erofsprefix here, I think fsoffset >> may be fine. > > Yes, fsoffset sounds good. I anticipate more filesystems will support > file-backed mounts in the future, making this option reusable. From my own kernel perspective, it's not possible for the majority of read-write fses especially have nested transaction (like `current->journal_info`) in addition to many deadlock factors without extra workqueue contexts. But for erofs it's safe. Thanks, Gao Xiang