NFS, access problem

Vladimir Chukharev chu at kemia.me.tut.fi
Thu Jun 30 08:41:13 GMT 2005


Hi,

I have a weird problem of access to files on an NFS-mounted
file system. I cannot read (and write to) files, which I think
I should be able to read and write.

I checked everything what I can think of, but I cannot find
why access is denied.

I tried to google the problem, no result. It is not FreeBSD
specific, nevertheless I will ask here.


What has been checked:
permissions,
owner and group,
that I belong to the group on both computers,
correspondence of the groups on the two computers,
correspondence of /etc/group to /etc/gshadow on the server (FC3/AMD64),
number of groups I belong to (6 on client, 7 (or 6 as a test) on server),
that SELinux on the server is disabled,
that the same is with a client under FreeBSD, Mandrake and Gentoo,
that /etc/exports on the server does not put any special restrictions,
that mount on the client is done without any special tricks,
that local system (i.e. FreeBSD) does not have flags on the files,
that there is no second name for the group, on both computers.


I am lost... What do I look at and do not see?
What else can be the reason?


A test case is prepared. One file belongs to group 'research',
another to group 'devel'. I cannot understand why I have no
access to the second file.


First, on the local machine (client).
++++++++++++++++++++++
chu at chu:/mnt/kemia/home/Research/Devel 09:38:10 $ cat test1
This I can read and write locally and over NFS.
chu at chu:/mnt/kemia/home/Research/Devel 09:48:52 $ cat test2
cat: test2: Permission denied
chu at chu:/mnt/kemia/home/Research/Devel 09:48:52 $ ls -Fail
total 24
12763141 drwxrws---   4 chu   devel     4096 Jun 29 22:00 ./
12763137 drwxr-sr-x  10 root  research  4096 Jun  8 16:53 ../
12913617 drwxrws---  21 chu   devel     4096 Mar  1 11:31 Instr/
12914575 drwxrws---  17 501   devel     4096 Mar 14 14:33 prog/
12770983 -rw-rw----   1 root  research    48 Jun 29 21:59 test1
12770877 -rw-rw----   1 root  devel       58 Jun 29 22:00 test2
chu at chu:/mnt/kemia/home/Research/Devel 09:48:53 $ ls -Failn
total 24
12763141 drwxrws---   4 540  1007  4096 Jun 29 22:00 ./
12763137 drwxr-sr-x  10 0    1001  4096 Jun  8 16:53 ../
12913617 drwxrws---  21 540  1007  4096 Mar  1 11:31 Instr/
12914575 drwxrws---  17 501  1007  4096 Mar 14 14:33 prog/
12770983 -rw-rw----   1 0    1001    48 Jun 29 21:59 test1
12770877 -rw-rw----   1 0    1007    58 Jun 29 22:00 test2
chu at chu:/mnt/kemia/home/Research/Devel 09:48:53 $ grep -i chu /etc/group | wc -l
        6
chu at chu:/mnt/kemia/home/Research/Devel 09:48:53 $ grep -iE '(devel)|(research)' /etc/group
research:*:1001:chu
devel:*:1007:nick,chu
chu at chu:/mnt/kemia/home/Research/Devel 09:48:53 $ uname -a
FreeBSD chu.xxx.xxx.xx 5.4-STABLE FreeBSD 5.4-STABLE #30: Mon Jun 20 19:39:44 EEST 2005     root at chu.xxx.xxx.xx:/usr/obj/usr/src/sys/CHU  i386
chu at chu:/mnt/kemia/home/Research/Devel 10:07:35 $ grep kemia /etc/fstab
kemia.xxx.xxx.xx:/home           /mnt/kemia/home         nfs     rw,bg,tcp,intr,soft,noauto      0       0
chu at chu:/mnt/kemia/home/Research/Devel 10:16:13 $ grep chu /etc/passwd
chu:*:540:540:Vladimir Chukharev:/home/chu:/usr/local/bin/bash
--------------------

Now, on the remote server, which exports the FS.
++++++++++++++++++++
chu at kemia:/home/Research/Devel 09:53:46 $ cat test1
This I can read and write locally and over NFS.
chu at kemia:/home/Research/Devel 09:53:49 $ cat test2
This I can read and write only locally, but not over NFS.
chu at kemia:/home/Research/Devel 09:53:49 $ ls -Fail
total 24
12763141 drwxrws---   4 chu  devel    4096 Jun 29 22:00 ./
12763137 drwxr-sr-x  10 root research 4096 Jun  8 16:53 ../
12913617 drwxrws---  21 chu  devel    4096 Mar  1 11:31 Instr/
12914575 drwxrws---  17 nick devel    4096 Mar 14 14:33 prog/
12770983 -rw-rw----   1 root research   48 Jun 29 21:59 test1
12770877 -rw-rw----   1 root devel      58 Jun 29 22:00 test2
chu at kemia:/home/Research/Devel 09:53:49 $ ls -Failn
total 24
12763141 drwxrws---   4 540 1007 4096 Jun 29 22:00 ./
12763137 drwxr-sr-x  10   0 1001 4096 Jun  8 16:53 ../
12913617 drwxrws---  21 540 1007 4096 Mar  1 11:31 Instr/
12914575 drwxrws---  17 501 1007 4096 Mar 14 14:33 prog/
12770983 -rw-rw----   1   0 1001   48 Jun 29 21:59 test1
12770877 -rw-rw----   1   0 1007   58 Jun 29 22:00 test2
chu at kemia:/home/Research/Devel 09:53:49 $ grep -i chu /etc/group | wc -l
7
chu at kemia:/home/Research/Devel 09:53:49 $ grep -iE '(devel)|(research)' /etc/group
research:x:1001:nick,chu, [deleted]
devel:x:1007:nick,chu, [deleted]
chu at kemia:/home/Research/Devel 09:53:49 $ uname -a
Linux kemia.xx.xx.xx 2.6.10-1.770_FC3 #1 Thu Feb 24 18:09:38 EST 2005 x86_64 x86_64 x86_64 GNU/Linux
chu at kemia:/home/Research/Devel 09:53:49 $
chu at kemia:/home/Research/Devel 09:53:49 $ sudo grep -i chu /etc/gshadow | wc -l
7
chu at kemia:/home/Research/Devel 09:53:49 $ sudo egrep '(devel)|(research)' /etc/gshadow
research:::nick,chu, [deleted]
devel:::nick,chu, [deleted]
chu at kemia:/home/Research/Devel 09:53:49 $ cat /etc/exports
/home/Research  xxx.xxx.xx.0/255.255.255.0(sync,rw)
/home/Public    xxx.xxx.xx.0/255.255.255.0(sync,rw)
/home/users     xxx.xxx.xx.0/255.255.255.0(sync,rw)
/home           xxx.xxx.xx.0/255.255.255.0(sync,rw)
chu at kemia:/home/Research/Devel 10:07:20 $ grep chu /etc/passwd
chu:x:540:540:Vladimir Chukharev:/home/users/chu:/bin/bash
----------------------

Note, that the deleted part of the group devel is shorter, than that of research.
It is not the cause of the problem, I tried to make it short.

ANY ideas? Please?

Best regards,
-- 
V.Chukharev


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