From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C41E4C28CF5 for ; Wed, 26 Jan 2022 08:51:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238568AbiAZIvx (ORCPT ); Wed, 26 Jan 2022 03:51:53 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:60051 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238557AbiAZIvu (ORCPT ); Wed, 26 Jan 2022 03:51:50 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1643187110; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=pfOp64U0iYvSw+YJXe3pmYBUfoothO/ocAN1AyLo5xI=; b=iNv6FgCr2RzZBFMt/oAuSjVBhgEodPib8UPS9zGaQ5SmlRv3z9QkdJ+ws9yzMXNH2qu5AP URGfYotPfCrbjzGnp8zqKLct8awiYAnrbkNziZurjvSrp/FqAg6CprZLCRighrApH/SByz 33NQmGjwGlkACGNDVmMc2xoh5kGB0qY= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-528-8QxKUfNEP4SBWpgli8BY4w-1; Wed, 26 Jan 2022 03:51:44 -0500 X-MC-Unique: 8QxKUfNEP4SBWpgli8BY4w-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 2D402100C609; Wed, 26 Jan 2022 08:51:43 +0000 (UTC) Received: from warthog.procyon.org.uk (unknown [10.33.36.26]) by smtp.corp.redhat.com (Postfix) with ESMTP id BAD2B56F6A; Wed, 26 Jan 2022 08:51:36 +0000 (UTC) Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: <8f88459a-97e0-8b8d-3ec9-260d482a0d38@linux.alibaba.com> References: <8f88459a-97e0-8b8d-3ec9-260d482a0d38@linux.alibaba.com> <20220118131216.85338-1-jefflexu@linux.alibaba.com> <2815558.1643127330@warthog.procyon.org.uk> To: JeffleXu Cc: dhowells@redhat.com, linux-cachefs@redhat.com, xiang@kernel.org, chao@kernel.org, linux-erofs@lists.ozlabs.org, linux-fsdevel@vger.kernel.org, joseph.qi@linux.alibaba.com, bo.liu@linux.alibaba.com, tao.peng@linux.alibaba.com, gerry@linux.alibaba.com, eguan@linux.alibaba.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 00/20] fscache,erofs: fscache-based demand-read semantics MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <100894.1643187095.1@warthog.procyon.org.uk> Date: Wed, 26 Jan 2022 08:51:35 +0000 Message-ID: <100895.1643187095@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org JeffleXu wrote: > "/path/to/file+offset" > ^ > > Besides, what does the 'offset' mean? Assuming you're storing multiple erofs files within the same backend file, you need to tell the the cache backend how to find the data. Assuming the erofs data is arranged such that each erofs file is a single contiguous region, then you need a pathname and a file offset to find one of them. David