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 5E263C54E4A for ; Fri, 8 Mar 2024 07:53:01 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id D012A6B0340; Fri, 8 Mar 2024 02:53:00 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id CB15C6B0341; Fri, 8 Mar 2024 02:53:00 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B78F06B0342; Fri, 8 Mar 2024 02:53:00 -0500 (EST) 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 A82606B0340 for ; Fri, 8 Mar 2024 02:53:00 -0500 (EST) Received: from smtpin03.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 7ED2FC1392 for ; Fri, 8 Mar 2024 07:53:00 +0000 (UTC) X-FDA: 81873105720.03.88ADF72 Received: from mail-ej1-f51.google.com (mail-ej1-f51.google.com [209.85.218.51]) by imf11.hostedemail.com (Postfix) with ESMTP id 4B2AB40015 for ; Fri, 8 Mar 2024 07:52:58 +0000 (UTC) Authentication-Results: imf11.hostedemail.com; dkim=pass header.d=szeredi.hu header.s=google header.b=XEbLTyVt; spf=pass (imf11.hostedemail.com: domain of miklos@szeredi.hu designates 209.85.218.51 as permitted sender) smtp.mailfrom=miklos@szeredi.hu; dmarc=pass (policy=quarantine) header.from=szeredi.hu ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1709884378; 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=hrvCXGaVO3HhvR4A5xt8TDit+qLJ9i7NLCGUzaXWqIQ=; b=hXMp9mGZCY8Tu3K/swZje31fnL0FneOrM7hn3LDpT7agKeKeuVx2G6jlq1cByABVsv4jdD Ss3mpSP+o3uwNVWNOksIcA/dyQ1mn9/ekI0vrmHRUhpjijwgUocAH1F4ONJNVrvYm79PQd yWwJJx6eW8ZaDwB31kq8mBOWJLfwQeA= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1709884378; a=rsa-sha256; cv=none; b=Z/erNNNJ4ytecisYJkDNvUZywZs5YybwY95cUqWd1+YWInZdV75GyjPQAKSD1IKTKDRb54 MNtcas92TbzvtoklJEVeJqHna1R8pzitv0bQaOHztftp4ofwOZFNjdJVSoai4glkVVsOfQ /s0QJpmBN5+B8G4lYNZHRJiFe2KHJbw= ARC-Authentication-Results: i=1; imf11.hostedemail.com; dkim=pass header.d=szeredi.hu header.s=google header.b=XEbLTyVt; spf=pass (imf11.hostedemail.com: domain of miklos@szeredi.hu designates 209.85.218.51 as permitted sender) smtp.mailfrom=miklos@szeredi.hu; dmarc=pass (policy=quarantine) header.from=szeredi.hu Received: by mail-ej1-f51.google.com with SMTP id a640c23a62f3a-a44665605f3so256264966b.2 for ; Thu, 07 Mar 2024 23:52:57 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=szeredi.hu; s=google; t=1709884376; x=1710489176; darn=kvack.org; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=hrvCXGaVO3HhvR4A5xt8TDit+qLJ9i7NLCGUzaXWqIQ=; b=XEbLTyVtATkYSskZP+dwgQeEuqV2vjsJBr86xdjbKoNJ9kIffgK2ls0TM4FpDP34FQ 6E3GtG/hxMeOy3FCuEJxkCbqdWHWvy3bUXKf8YpOksMn23glNzsXBjorXoAvrgh0AHdS cvI7tU3/74AmJxXYqLvpP5U2A5aBAqIp/xp2k= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1709884376; x=1710489176; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=hrvCXGaVO3HhvR4A5xt8TDit+qLJ9i7NLCGUzaXWqIQ=; b=qe3nI3HAgZSsEjqt/qxeND4+pwmg35ghtjWMbbPGOX1RZ6MOoWZCBgeLhQpq57ANPh ZquISq6QAXrIh6Mw4JKpEzCxJJnLMzrvyFdAZ9kCuu3MN135LEBbZzLhSSKIQpQ0XLfG 2aBD4yPfYUU+qKYrF/1tDb1btsbwgUYrGe1QSHKrLar3GGAgajqNpn/a07rVg+U4+sr2 FHB0Oh25iGwptX+Bp8BCBRntmTVt/CoTLnCKS5aJbVf3aEn31NbmR6/lzZEs9U6o26/B wWwzLXX/O7QtkOfy/goZMDBhwgGzIDS6v5R44JWePNTC0mSea2Vpj6gNA1G1UYbJVtOj 9Atg== X-Forwarded-Encrypted: i=1; AJvYcCUIFSDEVrATEp9y9xODZ7/9CwFLwYb6OZ682wKu9QwkCK55oFLbTkljRQ2NM7n47728iTyF3BF+IG9aEoWqJFRWVzs= X-Gm-Message-State: AOJu0YyAn/ljsGkK9hZyyeu9GpeBwMWCB8vRKkhlt9V8qr0e8+7Ibko9 NtKrx2TCQpz82aZkfq+JNEfvnZ89tuxOMBlo4mGxsna68xE9F/pTFyIY0rF82JvvNHtN2MNJRPq c6JlbW3Gth/wX0AEGjF+23sQ4OMxq1WhtSgpjfQ== X-Google-Smtp-Source: AGHT+IGfxe+G6Hzhhm3qO2+tkAluEdwQIf++vT61Cv18s0V9jevPsUAy++K+ZRtxdczK/SgeeJRbLSjfJGJhUS+augI= X-Received: by 2002:a17:906:a2cf:b0:a44:488d:8e42 with SMTP id by15-20020a170906a2cf00b00a44488d8e42mr13783793ejb.66.1709884376420; Thu, 07 Mar 2024 23:52:56 -0800 (PST) MIME-Version: 1.0 References: <1668172.1709764777@warthog.procyon.org.uk> <1831809.1709807788@warthog.procyon.org.uk> In-Reply-To: <1831809.1709807788@warthog.procyon.org.uk> From: Miklos Szeredi Date: Fri, 8 Mar 2024 08:52:44 +0100 Message-ID: Subject: Re: [RFC PATCH] mm: Replace ->launder_folio() with flush and wait To: David Howells Cc: Matthew Wilcox , Trond Myklebust , Christoph Hellwig , Andrew Morton , Alexander Viro , Christian Brauner , Jeff Layton , linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, netfs@lists.linux.dev, v9fs@lists.linux.dev, linux-afs@lists.infradead.org, ceph-devel@vger.kernel.org, linux-cifs@vger.kernel.org, linux-nfs@vger.kernel.org, devel@lists.orangefs.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" X-Rspamd-Queue-Id: 4B2AB40015 X-Rspam-User: X-Rspamd-Server: rspam11 X-Stat-Signature: frbc9ouckx7o97h8x1xnekrefd1h8o8f X-HE-Tag: 1709884378-967979 X-HE-Meta: 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 fwqVEka/ BJR5c5Sb20AFDAKNDP98vm8OIIpAWbWiC033X0CiRDtHX3ZxhDWbP9uv+3PfonIXr2WgsrRl50Pf6aDxRyyf28FHfBwJX/Pgp25VWHeV+Jl2MBBwvw/i1RK8QTV9mx8VNWbfG+u3/vSUe4ld5yg8GpxM0HDSILKDY1EgTAtD524Si6eIXK5as1n+DSkRI5Mw0HV0MG8LbEY+5YE4yqgGuP2pn3j4Ww8BovihkDfGohLkn9UYbwpwR1AusEmLHy62+/Sy50imho62beTbDDDdWwG1ides1UJVQIQDIlhD06Xm+Dbk= 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 Thu, 7 Mar 2024 at 11:36, David Howells wrote: > (2) invalidate_inode_pages2() is used in some places to effect invalidation > of the pagecache in the case where the server tells us that a third party > modified the server copy of a file. What the right behaviour should be > here, I'm not sure, but at the moment, any dirty data will get laundered > back to the server. Possibly it should be simply invalidated locally or > the user asked how they want to handle the divergence. Skipping ->launder_page will mean there's a window where the data *will* be lost, AFAICS. Of course concurrent cached writes on different hosts against the same region (the size of which depends on how the caching is done) will conflict. But if concurrent writes are to different regions, then they shouldn't be lost, no? Without the current ->launder_page thing I don't see how that could be guaranteed. Thanks, Miklos