Return-Path: Received: from bombadil.infradead.org ([65.50.211.133]:49889 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751052AbdFRHej (ORCPT ); Sun, 18 Jun 2017 03:34:39 -0400 Date: Sun, 18 Jun 2017 00:34:38 -0700 From: Christoph Hellwig To: Chuck Lever Cc: Christoph Hellwig , linux-rdma@vger.kernel.org, Linux NFS Mailing List Subject: Re: [PATCH v2 19/19] sunrpc: Disable splice for krb5i Message-ID: <20170618073438.GA15358@infradead.org> References: <20170616151535.14210.34926.stgit@klimt.1015granger.net> <20170616152254.14210.48071.stgit@klimt.1015granger.net> <20170617150705.GA27917@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: Sender: linux-nfs-owner@vger.kernel.org List-ID: On Sat, Jun 17, 2017 at 01:23:24PM -0400, Chuck Lever wrote: > > > On Jun 17, 2017, at 11:07 AM, Christoph Hellwig wrote: > > > > On Fri, Jun 16, 2017 at 11:22:54AM -0400, Chuck Lever wrote: > >> Running a multi-threaded 8KB fio test (70/30 mix), three or four out > >> of twelve of the jobs fail when using krb5i. The failure is an EIO > >> on a read. > > > > Just curious: what is the backing fs that you tested with? I'd be > > curious if you see this on XFS for example. > > I was able to reproduce this with a tmpfs share and > with an XFS share on NVMe LUNs. Interesting. XFS actually locks out all writes while doing a buffered read, so we end up with two different read instance for the hash vs the data, which does indeed sound dangerous.