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 D77D1C83F11 for ; Mon, 28 Aug 2023 14:02:27 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 511C78E001A; Mon, 28 Aug 2023 10:02:27 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 4C1CE8E000E; Mon, 28 Aug 2023 10:02:27 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3899E8E001A; Mon, 28 Aug 2023 10:02:27 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id 297458E000E for ; Mon, 28 Aug 2023 10:02:27 -0400 (EDT) Received: from smtpin18.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id E4F5E80459 for ; Mon, 28 Aug 2023 14:02:26 +0000 (UTC) X-FDA: 81173678292.18.3AA8825 Received: from zeniv.linux.org.uk (zeniv.linux.org.uk [62.89.141.173]) by imf02.hostedemail.com (Postfix) with ESMTP id 06C1580030 for ; Mon, 28 Aug 2023 14:02:24 +0000 (UTC) Authentication-Results: imf02.hostedemail.com; dkim=pass header.d=linux.org.uk header.s=zeniv-20220401 header.b="Cys3/JAy"; dmarc=pass (policy=none) header.from=zeniv.linux.org.uk; spf=none (imf02.hostedemail.com: domain of viro@ftp.linux.org.uk has no SPF policy when checking 62.89.141.173) smtp.mailfrom=viro@ftp.linux.org.uk ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1693231345; h=from:from:sender: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=EoGjlAqIr84+dzTRIVSh6MnXuXBwrPpcJyhAY3N5ock=; b=HFkVXQkqaMSjAiad1Ely08HoHMOlYeWNWsW3x/WzQIimkv7zc8A4ooTX+AJI5DR8abU0Cz GZHBE5b1NOXU1Wjutepnu74fKR8ybs3H8AJQFE2x/IJx/g3Yz376aZ197BKvD8j5YsX8mO XNRe4gyAAB8WVXGfBxOU9XsrhwMD0cM= ARC-Authentication-Results: i=1; imf02.hostedemail.com; dkim=pass header.d=linux.org.uk header.s=zeniv-20220401 header.b="Cys3/JAy"; dmarc=pass (policy=none) header.from=zeniv.linux.org.uk; spf=none (imf02.hostedemail.com: domain of viro@ftp.linux.org.uk has no SPF policy when checking 62.89.141.173) smtp.mailfrom=viro@ftp.linux.org.uk ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1693231345; a=rsa-sha256; cv=none; b=Ue+eBFgRYtwr1pqAJn9JOGqKtKll4HUQMGwyHUd4mzb2WSFJl7frJEDqbEEh8w38YyI20g ROK2ZtZrggxGZZpzXv7okQVx35qGaw1UmkZuQ2Te39Z1epCTKDX1r9iNqlQpGQ8tqC6EW8 Njez78hBnC4s6bwI3yvl8OHwd7BBXb4= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=linux.org.uk; s=zeniv-20220401; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=EoGjlAqIr84+dzTRIVSh6MnXuXBwrPpcJyhAY3N5ock=; b=Cys3/JAywwflbjKeLLbxLR4Pml 1ZIuH88594x0nLpO6iJLXX9l6sI1h8ZkRVdCon46JySP7xwVSIy6uJlVUPCBG0I1jMUBp/0W9K9uT GCXP/OFE+JrmC3Pa+vZcLym98yS0JgfF9SpK8F8b18qNPjfvCtYSzNZ2k1S35WDywJTHF23uRdIPl X360jIARja8/zh1+SEIlBXc4nXvwCf4DxcPHjnlmChlDL/j2yB9CBDj1MRvDfFoTePW35BIjZXSeZ oEnIi346oyjWFuEc9Uk6usuZ2p/gFgmA/OPtZ8mAicao0VPMQqLBW8+t2E5sM608aGZst3O1yE7EK cxVGuQGg==; Received: from viro by zeniv.linux.org.uk with local (Exim 4.96 #2 (Red Hat Linux)) id 1qacoc-001ZYo-2Z; Mon, 28 Aug 2023 14:02:03 +0000 Date: Mon, 28 Aug 2023 15:02:02 +0100 From: Al Viro To: Christoph Hellwig Cc: Matthew Wilcox , Jens Axboe , Xiubo Li , Ilya Dryomov , Christian Brauner , Theodore Ts'o , Jaegeuk Kim , Chao Yu , Miklos Szeredi , Andreas Gruenbacher , "Darrick J. Wong" , Trond Myklebust , Anna Schumaker , Damien Le Moal , Andrew Morton , linux-block@vger.kernel.org, ceph-devel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, cluster-devel@redhat.com, linux-xfs@vger.kernel.org, linux-nfs@vger.kernel.org, linux-mm@kvack.org, Hannes Reinecke Subject: Re: [PATCH 03/12] filemap: update ki_pos in generic_perform_write Message-ID: <20230828140202.GX3390869@ZenIV> References: <20230601145904.1385409-1-hch@lst.de> <20230601145904.1385409-4-hch@lst.de> <20230827194122.GA325446@ZenIV> <20230828123023.GA11084@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230828123023.GA11084@lst.de> X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 06C1580030 X-Stat-Signature: uhwbzt866xegh8h6hgzdj1j6693u7wjz X-Rspam-User: X-HE-Tag: 1693231344-167732 X-HE-Meta: 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 5I2OTLgh 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 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 Mon, Aug 28, 2023 at 02:30:23PM +0200, Christoph Hellwig wrote: > On Sun, Aug 27, 2023 at 08:41:22PM +0100, Al Viro wrote: > > That part is somewhat fishy - there's a case where you return a positive value > > and advance ->ki_pos by more than that amount. I really wonder if all callers > > of ->write_iter() are OK with that. Consider e.g. this: > > This should not exist in the latest version merged by Jens. Can you > check if you still see issues in the version in the block tree or > linux-next. Still does - the problem has migrated into direct_write_fallback(), but that hadn't changed the situation. We are still left with ->ki_pos bumped by generic_perform_write() (evaluated as an argument of direct_write_fallback() now) and *not* retraced in case when direct_write_fallback() decides to discard the buffered write result. Both in -next and in mainline (since 6.5-rc1).