The function check_utf8() is in RHEL 4, but it has been removed since ~ 2.6.11 from kernel.org kernels. Furthermore, RHEL 5 does not contain this function. Fujitsu would like RHEL 4 NFS servers to be consistent with the RHEL 5 NFS servers by removing the UTF-8 check.

* Reference to the original patch by Bruce Fields:
http://www.linux-nfs.org/pipermail/nfsv4/2005-February/001175.html


Details from Fujitsu:
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RHN System ID:

Customer Contact Name:

 Ishikawa Yoshitaka

Description of Problem:

 Almost all the file systems do not check the filename be operated is valid
 UTF-8 or not, for example ext2/ext3/NFSv2/NFSv3, etc.
 If an ext3 file (directory) whose name is invalid UTF-8 and be exported
 through NFSv4, Client can not operate this file(directory).
 So we'd better not to do this check.

 About this problem, the maintainer of NFSv4 'J. Bruce Fields' said:
 -------------------------
 RFC3530 says NFSv4 filenames are in UTF-8, and that servers "should" reject
 filenames that aren't valid UTF-8.  Currently we do some incomplete UTF-8
 checking, but this turns out to be more of a hindrance than a help--if we
 export a file system with non-UTF8 names, things break.  We might be able to
 help things if we had some idea of the exported file system's charset and could
 do some translation.  For now, though, the simplest solution by far seems to be
 just to remove the UTF-8 checks, making NFSv4's behavior just like NFSv2/v3's.

Version-Release number of selected component:

 Red Hat Enterprise Linux Version Number: RHEL4
 Release Number:                          4.8 snapshot5
 Architecture:                            x86_64
 Kernel Version:                          kernel-2.6.9-88.EL
 Related Package Version:                 None
 Related Middleware / Application:        None

Drivers or hardware or architecture dependency:

 None

How reproducible:

 Every time

Step to Reproduce:

 Server Settings:
   # cat /etc/exports
   /tmp *(rw,insecure,fsid=0,no_root_squash)

 Client:
   Execute following commands to reproduce:

   Step1:mount the nfsv4 fs and enter the mount dir
       # mount -t nfs4 [server]:/ /mnt
       # cd /mnt
   Step2:compile the reproduction program:
       # cp $somedir/check_utf8.c .
       # gcc -o check_utf8 check_utf8.c
   Step3:execute the reproduction program
       # ./check_utf8

Actual Results:

 Operations are rejected by NFS Server.

 # ./check_utf8
 Error: mkdir '??' failed. (Invalid argument)
 Error: opendir '??' failed. (Invalid argument)
 Error: rmdir '??' failes. (Invalid argument)
 Error: open '??' failed. (Invalid argument)
 Error: rename '??' to '??' failed. (Invalid argument)
 Error: unlink '??' failed. (Invalid argument)

Expected Results:

 Operations can be dealt by NFS Server.

 # ./check_utf8
 mkdir '??' ok.
 opendir '??' ok.
 rmdir '??' ok.
 open '??' ok.
 rename '??' to '??' ok.
 unlink file '??' ok.


Summary of actions taken to resolve issue:

 None

Location of diagnostic data:

 None

Hardware configuration:

 Model:       PRIMERGY TX150 S5
 CPU Info:    Intel(R) Xeon(R) CPU   3040  @ 1.86GHz
 Memory Info: 6GB

Business Impact:

 None.
 Target Release: 4.9
 Errata Request: No
 Hotfix Request: No
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