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b=gRJsNVcgQ9b9/aamX83T1THpiGBoNbun7e2YBuUibZpxVBifs/D/JFC8KwlYEHn17DvvKt D40r91JM2hXgVut6vW+l1LwrB5RyfWk8988PASY9mj80Os7I0ZPoLdfQffBgisSWiMTJWK oifVvqMPeVoOxHDbxnshbKF94wGZlTdYrMog5B5G9U2EfEDMiFpfphTPa0QO8ymtPg0zKD C5l0LH9K0T/xwb4Wtmv1K79gSu4Q/N3zpIHVcOEppgyazxG6yy5TP4bvMUsZKEojerjx2P s48UJ+XD4RKV+iPOAklHilqq6GjZV4zIEMSolexVTwnPBJTvLJbUBgAMqIGogw== Received: from localhost (gaia.codewreck.org [local]) by gaia.codewreck.org (OpenSMTPD) with ESMTPA id d3703de6; Mon, 17 Jun 2024 21:50:16 +0000 (UTC) Date: Tue, 18 Jun 2024 06:50:01 +0900 From: Dominique Martinet To: Christian Kastner Cc: David Howells , Andrea Righi , Eric Van Hensbergen , linux-afs@lists.infradead.org, linux-cifs@vger.kernel.org, v9fs@lists.linux.dev, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Luca Boccassi , TJ , Emanuele Rocca Subject: Re: [PATCH v5 40/40] 9p: Use netfslib read/write_iter Message-ID: References: <20231221132400.1601991-1-dhowells@redhat.com> <20231221132400.1601991-41-dhowells@redhat.com> <531994.1716450257@warthog.procyon.org.uk> <57e56ca5-bbbc-495a-926e-54d7e2f5e76c@debian.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <57e56ca5-bbbc-495a-926e-54d7e2f5e76c@debian.org> X-Rspamd-Server: rspam03 X-Rspam-User: X-Rspamd-Queue-Id: 102A81A0017 X-Stat-Signature: 1yaf3ahu964r35rzhyhqndpb5spa9145 X-HE-Tag: 1718661026-982177 X-HE-Meta: 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 XudbGOjQ v0QKcdaMkRsnatVRcPEu+ji606wZYg+qffjcJsa8/clzZ8MZHVp8tGdzIw6wBwNkj7Qszw06ou9Q7Mz0znWq3+30ngJneZm1/QyGGa0mb0xXSbsR8oUVWwYZOvtx78kGJ/VFTO6HC7/l3MS3O+bSLGl3Lgh5lfU3VWGgkpQoTmzYS/msX51dymKMveiN+6ogW9R4sfqHoTyCLLmMLQJawp8WlbzOOS8vP4IVFmH1FhcbJFNxhMEfdPstY0T9Zk6E19Ai9PKY2iKpWKlSkKyOSNW8pjhlcQzm2VElWfTabD2Zvzb3xHEqyUE7qcw== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000742, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Christian Kastner wrote on Mon, Jun 17, 2024 at 07:10:56PM +0200: > On 2024-05-31 17:06, Emanuele Rocca wrote: > > Meanwhile TJ (in CC) has been doing a lot of further investigation and > > opened https://bugzilla.kernel.org/show_bug.cgi?id=218916. > > just to loop back to the MLs: in the referenced bug, TJ posted an > analysis and and added a patch that fixed the issue for multiple testers. Thanks for the mail, one of these days I'll try to understand how to make bugzilla automatically put me in cc of all the 9p bugs.. Analysis and tentative fix are of great help! Looks like we now understand what's wrong -- if I understand the description correctly we know the correct size (files aren't modified in the background, just other threads within the VM, right?); and the problem is that the netfs IO reverts the size back to an incorrect value when it completes? If so then the fix looks odd to me, the problem ought to be fixed at the netfs/9p interface level, I don't see why an unbuffered read should update the size metadata when it's done... David, what do you think? -- Dominique Martinet | Asmadeus