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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id B1527C61CE7 for ; Wed, 11 Jun 2025 04:35:00 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 064C36B0088; Wed, 11 Jun 2025 00:35:00 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id F30CC6B0089; Wed, 11 Jun 2025 00:34:59 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id DD3BB6B008A; Wed, 11 Jun 2025 00:34:59 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id BB7926B0088 for ; Wed, 11 Jun 2025 00:34:59 -0400 (EDT) Received: from smtpin16.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 0020BC1B3C for ; Wed, 11 Jun 2025 04:34:58 +0000 (UTC) X-FDA: 83541854676.16.799A650 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf23.hostedemail.com (Postfix) with ESMTP id 2FD9A140007 for ; Wed, 11 Jun 2025 04:34:56 +0000 (UTC) Authentication-Results: imf23.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=q9pBvlIh; spf=none (imf23.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org; dmarc=none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1749616497; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=ARbjRh7/rnRbjvUmhBkINZLHyFvPiwwBlxyxyZKqeFE=; b=lcb6PLJv2P8vEB0HXUAq249au2oesSKPrSe9SDG/hE/XzB3sAOuHEayBAYvPO3YMPJGS71 lBSAKjSIU6Tgp/dUcp/Ru1pTNTHmmL2WlaVrCfuj/1wO2LFIYzLmnIa8j6ioqCI/F0081y f8LDnCUzS+S9UuwUm9j+DIaw6in0r6Y= ARC-Authentication-Results: i=1; imf23.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=q9pBvlIh; spf=none (imf23.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org; dmarc=none ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1749616497; a=rsa-sha256; cv=none; b=ovaeP05DeGQTYpv59JPa+wyDuNh0AZrj5WN5qh1O1Ni2biW4zst/DNGtU71R8IgYe3mrrf K3yZOOU0+Eo50yh7YIBbiR3B/UXmTFunIMijp7ZfFm0f9ZWeGjNCvGZu6AmGT4Qdy8cDeT Yk83rCwKXVovnpy2zYU8nNqtcE365vM= 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=ARbjRh7/rnRbjvUmhBkINZLHyFvPiwwBlxyxyZKqeFE=; b=q9pBvlIhw7CmlRzuGDAnChYrve l7tTw7U8A9waVV9TjNjbhlc/YRyCLndgjnkRd7FmfIzS5BubAMCF/FdGJabjwQ+aWf1AK0dgoYpk7 FEJN5Jc5zMRQiFtQh6Z8daA1FdCqLbPmzJq4DXufXapM/oRl6ih5reJcfJoz3crPmCmdqfwshsZ8x J0xGgZq3xr+aSlQD1DXfbBRmE+/upSARf2nNl9rUAe3sMQ5ww9zoG/I7FTqmDuhnaMgNZ2n/h+Uiu WkvF7UzDsq1q+zEHH3/kDyivsHYmapuok71Al/hYkiKU2IZmx2uqFbNTwEKyOrAZDOksk1mn6GOlx tZkJmq0Q==; Received: from willy by casper.infradead.org with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1uPDAo-0000000ADVi-2M9F; Wed, 11 Jun 2025 04:34:50 +0000 Date: Wed, 11 Jun 2025 05:34:50 +0100 From: Matthew Wilcox To: Christoph Hellwig Cc: "Darrick J. Wong" , Joanne Koong , miklos@szeredi.hu, brauner@kernel.org, linux-fsdevel@vger.kernel.org, linux-xfs@vger.kernel.org, bernd.schubert@fastmail.fm, kernel-team@meta.com, linux-mm@kvack.org, linux-nfs@vger.kernel.org Subject: Re: [PATCH v1 5/8] iomap: add iomap_writeback_dirty_folio() Message-ID: References: <20250606233803.1421259-1-joannelkoong@gmail.com> <20250606233803.1421259-6-joannelkoong@gmail.com> <20250609171444.GL6156@frogsfrogsfrogs> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 2FD9A140007 X-Stat-Signature: 6k4wdhyqjgtecosmeftgj4uws8fueeqc X-Rspam-User: X-HE-Tag: 1749616496-965439 X-HE-Meta: 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 YzegaelJ wwJWsHFAGBCTtEFS3akCiqyx46tuL8XQxsi6fQZg9OuGXUA9RA9IdrtUb81EWm0EIk/xMzkpi2kXE1gdPJH8yKj7a6eMu6NV//lbk28ZZnf1IvgKZbkGz8stg/Ip9GoyZFJXRFhbHJj4bmyALJNZoiT3h0sSsmZDzefWQ+oiPg8BEiYOKfxg+hsVlamWTECBt5Y3iMyUJ4P7pkDKRcOo1HmO26EQBKf6FAJlImmA2CzO4FMfIUmgDLN890Q2ElS8UHUKJ9YZtvRyIJWWxbAJ5bvstsQ== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Jun 09, 2025 at 08:59:53PM -0700, Christoph Hellwig wrote: > On Mon, Jun 09, 2025 at 10:14:44AM -0700, Darrick J. Wong wrote: > > > Where "folio laundering" means calling ->launder_folio, right? > > > > What does fuse use folio laundering for, anyway? It looks to me like > > the primary users are invalidate_inode_pages*. Either the caller cares > > about flushing dirty data and has called filemap_write_and_wait_range; > > or it doesn't and wants to tear down the pagecache ahead of some other > > operation that's going to change the file contents and doesn't care. > > > > I suppose it could be useful as a last-chance operation on a dirty folio > > that was dirtied after a filemap_write_and_wait_range but before > > invalidate_inode_pages*? Though for xfs we just return EBUSY and let > > the caller try again (or not). Is there a subtlety to fuse here that I > > don't know about? > > My memory might be betraying me, but I think willy once launched an > attempt to see if we can kill launder_folio. Adding him, and the > mm and nfs lists to check if I have a point :) I ... got distracted with everything else. Looking at the original addition of ->launder_page (e3db7691e9f3), I don't understand why we need it. invalidate_inode_pages2() isn't supposed to invalidate dirty pages, so I don't understand why nfs found it necessary to do writeback from ->releasepage() instead of just returning false like iomap does. There's now a new question of what the hell btrfs is up to with ->launder_folio, which they just added recently.