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 736D2C6FD1C for ; Thu, 23 Mar 2023 03:26:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230018AbjCWD0x (ORCPT ); Wed, 22 Mar 2023 23:26:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40124 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229819AbjCWD0v (ORCPT ); Wed, 22 Mar 2023 23:26:51 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 15F9B2595D; Wed, 22 Mar 2023 20:26:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=PUObvHze7ahZs4YqVo863XKMZRFBTex2ma8xL3E1SBg=; b=UQdaznGs+lhoyIxI57a5NKI1FA 8vGXVzusnjeKgdlRswl0gug/YXUxtHVB8dQQ2FgGic9Mh36NEHdYGouSeQy4XX2O98BwuPJHevXeJ hESZKTO6v+wPdAaKHwAJO/XqS1jDbH+OQZTZ2Bsw/SGT7oSdmEf6J6tkYMCEbjeyOenvnj+aPwSz0 CuI2aM7rd4Y1f/88A5apulVmjX/CKvjErMkcvXbqKV9PtRB2hw58FSKdnD3oIbAxsbNijtcgqXglO WXrldsfouoiIBNLdbGa4aRmP5vwIikNQzvADP/ZLTJMF7d4JoxBxlLL81T5cB3YKWsTmlMqe2ieCN y/e1GpEg==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1pfBb9-003dTO-Ke; Thu, 23 Mar 2023 03:26:43 +0000 Date: Thu, 23 Mar 2023 03:26:43 +0000 From: Matthew Wilcox To: Ritesh Harjani Cc: Theodore Tso , Andreas Dilger , linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH 04/31] ext4: Convert ext4_finish_bio() to use folios Message-ID: References: <20230126202415.1682629-5-willy@infradead.org> <87ttyy1bz4.fsf@doe.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87ttyy1bz4.fsf@doe.com> Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org On Mon, Mar 06, 2023 at 02:40:55PM +0530, Ritesh Harjani wrote: > "Matthew Wilcox (Oracle)" writes: > > > Prepare ext4 to support large folios in the page writeback path. > > Sure. I am guessing for ext4 to completely support large folio > requires more work like fscrypt bounce page handling doesn't > yet support folios right? > > Could you please give a little background on what all would be required > to add large folio support in ext4 buffered I/O path? > (I mean ofcourse other than saying move ext4 to iomap ;)) > > What I was interested in was, what other components in particular for > e.g. fscrypt, fsverity, ext4's xyz component needs large folio support? > > And how should one go about in adding this support? So can we move > ext4's read path to have large folio support to get started? > Have you already identified what all is missing from this path to > convert it? Honestly, I don't know what else needs to be done beyond this patch series. I can point at some stuff and say "This doesn't work", but in general, you have to just enable it and see what breaks. A lot of the buffer_head code is not large-folio safe right now, so that's somewhere to go and look. Or maybe we "just" convert to iomap, and never bother fixing the bufferhead code for large folios. > > Also set the actual error in the mapping, not just -EIO. > > Right. I looked at the history and I think it always just had EIO. > I think setting the actual err in mapping_set_error() is the right thing > to do here. > > > > > Signed-off-by: Matthew Wilcox (Oracle) > > w.r.t this patch series. I reviewed the mechanical changes & error paths > which converts ext4 ext4_finish_bio() to use folio. > > The changes looks good to me from that perspective. Feel free to add - > Reviewed-by: Ritesh Harjani (IBM) Thanks!