From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261381AbVAGSNA (ORCPT ); Fri, 7 Jan 2005 13:13:00 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261365AbVAGSLT (ORCPT ); Fri, 7 Jan 2005 13:11:19 -0500 Received: from omx3-ext.sgi.com ([192.48.171.20]:1229 "EHLO omx3.sgi.com") by vger.kernel.org with ESMTP id S261424AbVAGSG2 (ORCPT ); Fri, 7 Jan 2005 13:06:28 -0500 From: Limin Gu Message-Id: <200501071805.j07I5R428218@dbear.engr.sgi.com> Subject: Re: [RFC][PATCH] a revised job patch (with jobfs) To: kaigai@ak.jp.nec.com (Kaigai Kohei) Date: Fri, 7 Jan 2005 10:05:27 -0800 (PST) Cc: linux-kernel@vger.kernel.org, jengelh@linux01.gwdg.de (Jan Engelhardt), holt@sgi.com, jeffrey.hundstad@mnsu.edu, schwab@suse.de, rusty@rustcorp.com.au, chrisw@osdl.org, pagg@oss.sgi.com, limin@dbear.engr.sgi.com (Limin Gu) In-Reply-To: <41DE7C69.3030008@ak.jp.nec.com> from "Kaigai Kohei" at Jan 07, 2005 09:11:21 PM X-Mailer: ELM [version 2.5 PL3] MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org > > Hi, Limin Gu > > This JOB-fs approach is so ambitious, I think. > I tried to apply your JOB-fs patch toward 2.6.9, > then I noticed some promlems as follows. Hi KaiGai Kohei, Thank you for your interest in job. I am planning to post a slightly modified version of job patch against 2.6.10 pretty soon, and also the pointer to the job userland library and commands. > > (1) The JOB-fs patch needs include/linux/jobctl.h and include/linux/job_acct.h. > But these are contained in linux-2.6.9-job.patch, not JOB-fs patch. > Since those patches conflict, we need to extract the jobctl.h and job_acct.h > from linux-2.6.9-job.patch. The jobfs patch I posted last time should not need include/linux/jobctl.h and include/linux/job_acct.h, it only needed include/linux/job.h. I don't know why you had that problem. Your questions below 2-4 are all related to how to use job in the userland. We provide an extensive job library (libjob.so) for C codes, and serveral job commands for shell enviroment. User should use the library and commands instead of directly use /bin/mkdir and echo, the reason is that we want to maintain the job library and command the same as before and we want jobfs as simple as possible. > > (2) The return value of mkdir() under the /jids is strange. Yes, the return value is hacked to return the newly created jid. > The directory of 'jids' has a mkdir() method implemented by jobfs_mkdir(). > Since jobfs_mkdir() returns the result of job_create() transparently, > my mkdir operations alwaly failed. > ---------------- > /* > * job_create - create a new job and attache the calling process to it. > * @jid: new job id > * @user: job owner > * @options: not used > * > * return 0 on job is DISABLE, -errno on failure, 1 on success > */ > ---------------- > This is the description of job_create(). This returns 1 on success, > but VFS layer recognize it as a failure. > > I modified this as follows: > --- job.c 2005-01-06 20:03:47.000000000 +0900 > +++ kaigai_job.c 2005-01-07 20:16:55.518703400 +0900 > @@ -1505,5 +1505,5 @@ > return -EINVAL; > ret = job_create(jid, current->uid, 0); > - return ret; > + return (ret==1) ? 0 : ((ret==0) ? -EINVAL : ret); // Dirty? > } > > (3) We can not make a JOB by using a /bin/mkdir command. We provide job_create() library call for job creation. We also provide a library pam_job.so that allows job creation through PAM modules. For example, if add "account optional /lib/security/pam_job.so" line to /etc/pam.d/rlogin file, every rlogin will create a new job, and all the processes from that login are contained in the same job, unless somebody with proper permission decide to detach (processes or the job). > When I execute '/bin/mkdir' on shell program, new process was fork()'ed and execve()'ed. > This process calls mkdir() system-call and it create a JOB which contains only > the self process. > Then '/bin/mkdir' exits process, and the JOB created by '/bin/mkdir' contains no process. > So, the JOB was destroied soon. > For avoidance the problem, we need to 'create_job' command which calls mkdir() and > execve('/bin/bash') in the one process. > Or pagg+job framework need to allow the existance of the empty JOB. > > (4) "echo '123' > hid" fails by -EPERM. We have job_sethid() library call, and jsethid command avaible. > When we open the 'hid' with O_TRUNC flag, operation returns -EPERM. > setattr() method of 'hid' was called on extention of sys_open(). > * sys_open() -> filp_open() -> open_namei() -> may_open() > -> do_truncate() (When O_TRUNC was appended) > -> notify_change() > -> inode's setattr() (It always returns -EPERM.) > If we can't use 'echo', it's pretty inexpediency. > > And, would you have this discussion on PAGG-ML also ? > Because LKML has huge traffic, I have not noticed job-fs for two weeks. orz > Thanks. Good idea. Thanks! I am planning to post the new job patch(with jobfs implementation) and a new job userland rpm, i.e. the job library and commands that work with jobfs instead of the current ioctl calls, today on oss.sgi.com/projects/pagg. Let me know any problems. I appreciate your time. --Limin > -- > Linux Promotion Center, NEC > KaiGai Kohei >