From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out30-111.freemail.mail.aliyun.com (out30-111.freemail.mail.aliyun.com [115.124.30.111]) (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 3301723DE for ; Sat, 17 May 2025 13:38:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.111 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747489110; cv=none; b=SgyraShACQDeF9yifZxZheZpRkqY3BtDh4WYxRJXtsY0jOOAJ2pk2EZ8mFueam/1dcKWDod+HJGZjyUd/hx3Xifd1l87YUJdFXErGBUvtrrZLqtiInlaICX5eE0fb5kKtzwmiVqeYC/zDSajKohrfrcWZ4k6upHBL5WjBndnSFg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747489110; c=relaxed/simple; bh=pUvOofXDkPposa94RMhDdI/Ptt/GjorZ8vH901xrDfE=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=iN/4C7SwXNl+PPNktmIReAbNKO28ZJ6RpA3TCrJ0+pRIlR/FCFeYwQPG8CHuNwqBQpkYkURjlag3AA13uK9qb8kZs7OaKAOJ6h2fde4yJA85bk7VlPh77QWMw4aEJfdtwfNBOUd+P2hthYypkiPT/dWxyv+BG2TOsW8Wru4H9mI= 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=BFOArMBr; arc=none smtp.client-ip=115.124.30.111 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="BFOArMBr" DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1747489097; h=Message-ID:Date:MIME-Version:Subject:To:From:Content-Type; bh=/2y3CHuCm+oK+QhgXbMXa3N87TqXV+DMGRTukA22Eto=; b=BFOArMBr0yU4DB/W8ja8Om+HfxhkKUXWC/BA0cE5/uUhknykzciY26bGsDOGxvTeFG0x2ou7YqbmybIK+MrwDJGX+FUv9aTjHSyYWPNAWvQAMDZAkCUaSD3OWPSuSdbzYKEe/ktXdcGhzoQL7Pt3LgSA3f/LhaUH9K3kD+hFf78= Received: from 30.134.100.0(mailfrom:hsiangkao@linux.alibaba.com fp:SMTPD_---0Wb-FQtU_1747489084 cluster:ay36) by smtp.aliyun-inc.com; Sat, 17 May 2025 21:38:16 +0800 Message-ID: <60a7cad0-a415-41aa-b270-5b218d45d720@linux.alibaba.com> Date: Sat, 17 May 2025 21:38:02 +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 v7] erofs: add 'fsoffset' mount option to specify filesystem offset To: Sheng Yong , xiang@kernel.org, chao@kernel.org, zbestahu@gmail.com, jefflexu@linux.alibaba.com, dhavale@google.com, lihongbo22@huawei.com Cc: linux-erofs@lists.ozlabs.org, linux-kernel@vger.kernel.org, Sheng Yong , Wang Shuai References: <20250517090544.2687651-1-shengyong1@xiaomi.com> From: Gao Xiang In-Reply-To: <20250517090544.2687651-1-shengyong1@xiaomi.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 2025/5/17 17:05, Sheng Yong wrote: > From: Sheng Yong > > When attempting to use an archive file, such as APEX on android, > as a file-backed mount source, it fails because EROFS image within > the archive file does not start at offset 0. As a result, a loop > or a dm device is still needed to attach the image file at an > appropriate offset first. Similarly, if an EROFS image within a > block device does not start at offset 0, it cannot be mounted > directly either. > > To address this issue, this patch adds a new mount option `fsoffset=x' > to accept a start offset for the primary device. The offset should be > aligned to the block size. EROFS will add this offset before performing > read requests. > > Signed-off-by: Sheng Yong > Signed-off-by: Wang Shuai Reviewed-by: Gao Xiang Thanks, Gao Xiang