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.
(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.
(2) The return value of mkdir() under the /jids is strange.
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.
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.
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.
--
Linux Promotion Center, NEC
KaiGai Kohei <kaigai@xxxxxxxxxxxxx>
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