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 39A2AC433EF for ; Wed, 30 Mar 2022 15:55:54 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id BA5A58D0001; Wed, 30 Mar 2022 11:55:53 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id B55C36B0073; Wed, 30 Mar 2022 11:55:53 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A1D918D0001; Wed, 30 Mar 2022 11:55:53 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0070.hostedemail.com [216.40.44.70]) by kanga.kvack.org (Postfix) with ESMTP id 947AB6B0072 for ; Wed, 30 Mar 2022 11:55:53 -0400 (EDT) Received: from smtpin26.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 56410182751BA for ; Wed, 30 Mar 2022 15:55:53 +0000 (UTC) X-FDA: 79301503386.26.61FF4E6 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) by imf22.hostedemail.com (Postfix) with ESMTP id DCB02C0003 for ; Wed, 30 Mar 2022 15:55:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; 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=HMOfcZjpKd4HXdTf9ncMsCYUAoRwb/T1kB389y4bGdM=; b=vGlnpbNoOXVcnZwa9UF4XeaYjg WhSwj4N324o9z4cmAPpBHKLuGFaSQDMnT2YLY1wfdVblptnzehIXDuv9lkPIlElrn2MrE7VX7Glft UACY82x8M8Jv6swJSFUDw7eh4N+BahXF+TuslARHWS8UJQqPM+YPM8gcr6yZa32K49JMRWPeJL+z5 PX0lW2IbmXB+otVjy8FmuXPTYqXNiQHPtYVvcNvP02ykgn7Kk2sHeYMjQbJ1QTfY99WjV9cRWRtnJ GqqqB2jqMAzL0gJ2pAsmJnSEVnlL60AGLGdKckmYakWKDAttkG47zhFguWE7IYditonyLJoTItjnH Dp600qZg==; Received: from hch by bombadil.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1nZafi-00Gh5T-DI; Wed, 30 Mar 2022 15:55:46 +0000 Date: Wed, 30 Mar 2022 08:55:46 -0700 From: Christoph Hellwig To: Theodore Ts'o Cc: Linus Torvalds , Jan Kara , Matthew Wilcox , Brian Foster , Linux-MM , linux-fsdevel , linux-xfs , Hugh Dickins , Namjae Jeon , Ashish Sangwan , Ext4 Developers List Subject: Re: writeback completion soft lockup BUG in folio_wake_bit() Message-ID: References: <20220318131600.iv7ct2m4o52plkhl@quack3.lan> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html X-Stat-Signature: 4upxck5skh8uqo7pmh85sqsgbmsrubh9 X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: DCB02C0003 Authentication-Results: imf22.hostedemail.com; dkim=pass header.d=infradead.org header.s=bombadil.20210309 header.b=vGlnpbNo; dmarc=none; spf=none (imf22.hostedemail.com: domain of BATV+ea9b0106c62401bc49c3+6793+infradead.org+hch@bombadil.srs.infradead.org has no SPF policy when checking 198.137.202.133) smtp.mailfrom=BATV+ea9b0106c62401bc49c3+6793+infradead.org+hch@bombadil.srs.infradead.org X-Rspam-User: X-HE-Tag: 1648655752-817144 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: On Sat, Mar 19, 2022 at 12:23:04PM -0400, Theodore Ts'o wrote: > So the thing that I've been waiting to do for a while is to replace > the whole data=ordered vs data=writeback and dioread_nolock and > dioread_lock is a complete reworking of the ext4 buffered writeback > path, where we write the data blocks *first*, and only then update the > ext4 metadata. > *) Determining where the new allocated data blockblocks should be, and > preventing those blocks from being used for any other purposes, but > *not* updating the file system metadata to reflect that change. > > *) Submit the data block write > > *) On write completion, update the metadata blocks in a kernel thread. I think that would be easily done by switching to the iomap buffered I/O code, which is very much built around that model.