From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: linux-nfs-owner@vger.kernel.org Received: from smtp-out.cae.wisc.edu ([144.92.12.194]:45762 "EHLO smtp-out.cae.wisc.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756810AbaISRUK (ORCPT ); Fri, 19 Sep 2014 13:20:10 -0400 Message-ID: <541C6499.3080606@engr.wisc.edu> Date: Fri, 19 Sep 2014 12:15:05 -0500 From: Ken Hahn MIME-Version: 1.0 To: Trond Myklebust CC: Linux NFS Mailing List Subject: Re: NFS Kernel Bug References: <541AD7E5.8020409@engr.wisc.edu> <1411056020.10845.1.camel@leira.trondhjem.org> In-Reply-To: <1411056020.10845.1.camel@leira.trondhjem.org> Content-Type: text/plain; charset=UTF-8 Sender: linux-nfs-owner@vger.kernel.org List-ID: Hello, I work with drews@engr.wisc.edu. On 09/18/2014 11:00 AM, Trond Myklebust wrote: >> >> Argh. This is a situation where the client shouldn't have called >> OPEN_DOWNGRADE, but should have done a CLOSE. The issue is that the >> client opens the file with OPEN4_SHARE_ACCESS_BOTH, so it is not >> allowed to downgrade to OPEN4_SHARE_ACCESS_READ. Instead it should >> have closed the file, and then used the delegation... >> > > Does the following patch help (and does it still fix your original > bugreport)? I tried it out, patching the Debian 3.14.15 kernel.. had to alter the patch a tiny bit, but I don't think I messed up any real functionality. Indeed it passes the old test, and avoids the new bug too. Thanks! -Ken Hahn Here's the altered patch for what it is worth (for anyone else using the current debian backports kernel): --- a/fs/nfs/nfs4proc.c +++ b/fs/nfs/nfs4proc.c @@ -2560,20 +2560,22 @@ static void nfs4_close_prepare(struct rpc_task *task, void *data) is_rdwr = test_bit(NFS_O_RDWR_STATE, &state->flags); is_rdonly = test_bit(NFS_O_RDONLY_STATE, &state->flags); is_wronly = test_bit(NFS_O_WRONLY_STATE, &state->flags); - if (is_rdonly || is_rdwr) - calldata->arg.fmode |= FMODE_READ; - if (is_wronly || is_rdwr) - calldata->arg.fmode |= FMODE_WRITE; + calldata->arg.fmode = 0; if (state->n_rdwr == 0) { - if (state->n_rdonly == 0) { - call_close |= is_rdonly || is_rdwr; - calldata->arg.fmode &= ~FMODE_READ; - } - if (state->n_wronly == 0) { - call_close |= is_wronly || is_rdwr; - calldata->arg.fmode &= ~FMODE_WRITE; - } - } + if (state->n_rdonly == 0) + call_close |= is_rdonly; + else if (is_rdonly) + calldata->arg.fmode |= FMODE_READ; + if (state->n_wronly == 0) + call_close |= is_wronly; + else if (is_wronly) + calldata->arg.fmode |= FMODE_WRITE; + } else if (is_rdwr) + calldata->arg.fmode |= FMODE_READ|FMODE_WRITE; + + if (calldata->arg.fmode == 0) + call_close |= is_rdwr; + if (!nfs4_valid_open_stateid(state)) call_close = 0; spin_unlock(&state->owner->so_lock); -- 1.9.3