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 9503DC433FE for ; Tue, 10 May 2022 06:48:06 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 049F16B0072; Tue, 10 May 2022 02:48:06 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id F39606B0073; Tue, 10 May 2022 02:48:05 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id DFFF26B0074; Tue, 10 May 2022 02:48:05 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id CEC366B0072 for ; Tue, 10 May 2022 02:48:05 -0400 (EDT) Received: from smtpin26.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id A6172314D2 for ; Tue, 10 May 2022 06:48:05 +0000 (UTC) X-FDA: 79448903730.26.EED4A1B Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) by imf04.hostedemail.com (Postfix) with ESMTP id 12971400A7 for ; Tue, 10 May 2022 06:47:54 +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=hSOy7qsmVu3PqugjLk/Ti9DKDnpY0bkOOlrS22BpeSQ=; b=Ei0kSog1Hutzu9lHEsIUI6Xylk RdQyvqMN9IoS+J81JaK063GFA4StvRa6GL3KWcnid3qcm0X+egQhkjmAS/d7JW5VsqVRvf3FNOJlb wvUpwkfWtpS0kBJ1rntxvhyWQWEu2OiI9vhoMzEwZUHm2d6CmlBSTw4G16xe7nFceoARw4mNtBucH +rTGH1kg25iL6OU2PE6F34QTeDS1jB2SD9Mg65NSQKbRj0JVTLMMP1NvBPepfOimQxLVVN21y2Vs3 e9Sqund1zEwOiJ+JU8tycN01aXeq1stmRi40hWtNsjtcF0ZAvu8T84pOX2bX4eX/82doI5Xa9qvrc 4oDDS+KA==; Received: from hch by bombadil.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1noJf5-000DcC-OM; Tue, 10 May 2022 06:47:59 +0000 Date: Mon, 9 May 2022 23:47:59 -0700 From: Christoph Hellwig To: Dave Chinner Cc: "Darrick J. Wong" , Stefan Roesch , io-uring@vger.kernel.org, kernel-team@fb.com, linux-mm@kvack.org, linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: [RFC PATCH v1 11/18] xfs: add async buffered write support Message-ID: References: <20220426174335.4004987-12-shr@fb.com> <20220426225652.GS1544202@dread.disaster.area> <30f2920c-5262-7cb0-05b5-6e84a76162a7@fb.com> <20220428215442.GW1098723@dread.disaster.area> <19d411e5-fe1f-a3f8-36e0-87284a1c02f3@fb.com> <20220506092915.GI1098723@dread.disaster.area> <31f09969-2277-6692-b204-f884dc65348f@fb.com> <20220509232425.GQ1098723@dread.disaster.area> <20220509234424.GX27195@magnolia> <20220510011205.GR1098723@dread.disaster.area> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220510011205.GR1098723@dread.disaster.area> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html X-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 12971400A7 X-Stat-Signature: cwswbti4zmf7xcakskt3opgz9cftygus Authentication-Results: imf04.hostedemail.com; dkim=pass header.d=infradead.org header.s=bombadil.20210309 header.b=Ei0kSog1; spf=none (imf04.hostedemail.com: domain of BATV+237a309e1dc5667e2ea1+6834+infradead.org+hch@bombadil.srs.infradead.org has no SPF policy when checking 198.137.202.133) smtp.mailfrom=BATV+237a309e1dc5667e2ea1+6834+infradead.org+hch@bombadil.srs.infradead.org; dmarc=none X-HE-Tag: 1652165274-153731 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 Tue, May 10, 2022 at 11:12:05AM +1000, Dave Chinner wrote: > > I still don't understand why /any/ of this is necessary. When does > > iocb->ki_filp->f_inode != iocb->ki_filp->f_mapping->host? > > I already asked that question because I don't know the answer, > either. I suspect the answer is "block dev inodes" but that then > just raises the question of "how do we get them here?" and I don't > know the answer to that, either. I don't have the time to dig into > this and I don't expect anyone to just pop up with an answer, > either. So in the mean time, we can just ignore it for the purpose > of this patch set... Weird device nodes (including block device) is the answer. It never happens for a normal file system file struct that we'd see in XFS.