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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 11E23C76195 for ; Tue, 28 Mar 2023 02:32:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232502AbjC1CcR (ORCPT ); Mon, 27 Mar 2023 22:32:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35960 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232314AbjC1CcO (ORCPT ); Mon, 27 Mar 2023 22:32:14 -0400 Received: from nautica.notk.org (ipv6.notk.org [IPv6:2001:41d0:1:7a93::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 007BB19A9 for ; Mon, 27 Mar 2023 19:32:12 -0700 (PDT) Received: by nautica.notk.org (Postfix, from userid 108) id A3EEAC009; Tue, 28 Mar 2023 04:32:11 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=codewreck.org; s=2; t=1679970731; bh=81JrcBOQ6HGB6EQY6ONrHs1iEnNy5OL0G/POddTYXyU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=itRRNX2eB0DQ1gxwFaq2n5GXVmDLpjFHrgcqsjGJ+dOHE7zfcLBcnQYR0yUnIJ3Su OdG9BUu+up2wcGMEPp6BQW7uTQKXb68HOtRlDAgzno1FE5gNHt5zBj8tdvSZsoGaUM pjM7cIcv26x9FTIeMNggTP+l/g8m/fNsk15CJUPyXjFbeqnBcvMkb3eNvZiStqNb0J uiX1Zdl6sK/r37jlFdQFhfbROo9R9GTNRJ8jBLB90B1nLTH7lE0X2sWNshDFwoLpco 9KoNYifWhvKvQWXuidpVQtQ+zlXypwY6QTIC56L1Jq1wEwO6xVNaQP2s/KT+7FiGH6 NsjryNW1cZv4g== Received: from odin.codewreck.org (localhost [127.0.0.1]) by nautica.notk.org (Postfix) with ESMTPS id C7076C009; Tue, 28 Mar 2023 04:32:07 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=codewreck.org; s=2; t=1679970730; bh=81JrcBOQ6HGB6EQY6ONrHs1iEnNy5OL0G/POddTYXyU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=MM+pUzpA2WJXaL+n7pKT9cu9WJq2oGsHnA4aIxto+gfAe4pQCj8DClbYFGstZK/tS 5K+HgHPTKM5ydeKNVYtR3eQA9Vw+bs3fmna7oNRgX683+0i7e5x/6osVDJVbEMeG4R X4xX9S7K7DQAwG3HSEVbWzXmwPHjnKHxv+wA4H0rL2+CSInT8NV4jrXS5YYmzg0mZF VDoiePvb4CdCJMrNIT/nv5iFbWrU8aRXMvsD571g8hz5MZ5X3QjcCcvdDlR4BMXeeK 0ADH0U6zYvX97P+EVs257svnbcsN6Q7WTrkHRBczve0eFvsAwqH0mTU5G914g1Tnmj 5vNSOoQaza7zA== Received: from localhost (odin.codewreck.org [local]) by odin.codewreck.org (OpenSMTPD) with ESMTPA id 4a1f5aef; Tue, 28 Mar 2023 02:32:05 +0000 (UTC) Date: Tue, 28 Mar 2023 11:31:50 +0900 From: Dominique Martinet To: Luis Chamberlain Cc: Christian Schoenebeck , Eric Van Hensbergen , Josef Bacik , Jeff Layton , lucho@ionkov.net, v9fs-developer@lists.sourceforge.net, linux-kernel@vger.kernel.org, Amir Goldstein , Pankaj Raghav Subject: Re: 9p caching with cache=loose and cache=fscache Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Luis Chamberlain wrote on Mon, Mar 27, 2023 at 10:39:54AM -0700: > > I have fixed what > > I hope to be my last bug with the new patch series so it should be > > going into linux-next today. > > Nice, thanks, since kdevops relies on a host kernel though and we strive > to have stability for that, I personally like to recommend distro > kernels and so they're a few kernel releases out of date. So debian-testing > is on 6.1 as of today for example. > [...] > - opts: "ro,trans=virtio,version=9p2000.L,posixacl,cache=loose" > + opts: "ro,trans=virtio,version=9p2000.L,posixacl,cache=none" Yes, if you want something mostly coherent with the host, cache=none (or cache=mmap if you need mmap, iirc linux build does for linking? if you want to do that on guest...) is what you'll want to use on current kernels. > BTW the qemu wiki seems to suggest cache=loose and its why I used it on > kdevops as a default. What about the following so to avoid folks running > into similar issues? I can go and update the wiki too. I've added Christian in Cc for this point, he's more active on the qemu side (thread started here: https://lkml.kernel.org/r/ZA0FEyOtRBvpIXbi@bombadil.infradead.org ) I have no opinion on the current wording, the default is there for a reason and it's a safe default (none), and cache=loose is clearly described with "no attempts are made at consistency, intended for exclusive, read-only mounts" which I think ought to be clear enough (exclusive means not shared with the host), but if you think it's not clear enough it probably isn't. A word on the qemu wiki "if you want to share with host..." would probably be good though. -- Dominique