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 94FE2C04A6A for ; Wed, 16 Aug 2023 02:35:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241315AbjHPCe3 (ORCPT ); Tue, 15 Aug 2023 22:34:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46804 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241358AbjHPCeV (ORCPT ); Tue, 15 Aug 2023 22:34:21 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 861001FDF for ; Tue, 15 Aug 2023 19:34:20 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 21AF76218F for ; Wed, 16 Aug 2023 02:34:20 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 55073C433C8; Wed, 16 Aug 2023 02:34:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1692153259; bh=ILKLaDUtT4i0mLelpGeGRXNq7uFDFZtIQuCu+6LzedM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=PuEwZD18a+rqpN6UCHqN06Yf4QFXzCf+Tf9BmBrmkdCIJIBCkmqCsmctg8RBclgVV eeJ+SYK6N9DCir13+XKXkYpNE2bQADoV0p/40qnnWkJHP36HH+HrbQ+bFVF9Fqgplx yHaAEud6GmX6qIiZUfKLdWRTaigIhI8lZHajJkH0voVHAqrsnVB8sVPdXSAvr74x6/ Dgjv5w1tw8+EDOVn/ADghbjLDzGul6s0ijY+EliEvC9HwKzz4V/bPL+WTS5uWtBH3u qgVAdGdMYD0LNKeUrjsx5RUv+HnPyy/8Oz3mAc7KcT+dPzKz9dxem/5i4jwiECgZe/ GhkZZCkJUUk5w== Date: Tue, 15 Aug 2023 19:34:17 -0700 From: Eric Biggers To: Daniel Rosenberg Cc: linux-f2fs-devel@lists.sourceforge.net, Jaegeuk Kim , kernel-team@android.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH 0/1] Add 16K Support for f2fs Message-ID: <20230816023417.GA899@sol.localdomain> References: <20230816011432.1966838-1-drosen@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230816011432.1966838-1-drosen@google.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Aug 15, 2023 at 06:14:31PM -0700, Daniel Rosenberg via Linux-f2fs-devel wrote: > F2fs filesystems currently have two large restrictions around block size. > The block size must equal the page size, and the block size must be 4096. > > The following patch, along with the associated f2fs-tools patch set, relax the > latter restriction, allowing you to use 16K block size f2fs on a 16K page size > system. It does not allow mounting 4K block size f2fs on a 16k page system. > > Doing that would require a lot more work, requiring a refactor of all block > sized struct similar to the userspace patches, as well as handling the block > reading/writing at sub page boundaries. As far as I know, buffer_heads are > still the main way this is handled in other filesystems. Is there a different > option there? I know there's a general desire to move away from buffer_heads, > but I don't know of any replacements covering that use case. And it would feel > a bit silly to not be able to read older filesystems from a 16k system... iomap is the replacement for buffer heads. See https://lwn.net/Articles/935934 - Eric