Administration Reference

fs exportafs

Purpose

Reports or sets whether the machine can export AFS to clients of other file systems

Synopsis

fs exportafs -type <exporter name>  
        [-start <start/stop translator (on | off)>] 
        [-convert <convert from afs to unix mode (on | off)>] 
        [-uidcheck <run on strict 'uid check' mode (on | off)>] 
        [-submounts <allow nfs mounts to subdirs of /afs/.. (on | off)>]
        [-help]
   
fs exp -t <exporter name>  
       [-st <start/stop translator (on | off)>]
       [-c <convert from afs to unix mode (on | off)>]
       [-u <run on strict 'uid check' mode (on | off)>]
       [-su <allow nfs mounts to subdirs of /afs/.. (on | off)>]  
       [-help]

Description

The fs exportafs command sets (if the -start argument is provided) or reports (if it is omitted) whether the machine can reexport the AFS filespace to clients of a non-AFS file system. To control certain features of the translation protocol, use the following arguments:

To control whether the UNIX group and other mode bits on an AFS file or directory are set to match the owner mode bits when it is exported to the non-AFS file system, use the -convert argument.
To control whether tokens can be placed in a credential structure identified by a UID that differs from the local UID of the entity that is placing the tokens in the structure, use the -uidcheck argument. The most common use is to control whether issuers of the knfs command can specify a value for its -id argument that does not match their local UID on the NFS/AFS translator machine.
To control whether users can create mounts in the non-AFS filespace to an AFS directory other than /afs, use the -submounts argument.

Options

-type

Names the alternate file system to which to reexport the AFS filespace. The only acceptable value is nfs, in lowercase letters only.

-start

Enables the local machine to reexport the AFS filespace if the value is on, or disables it if the value is off. Omit this argument to report the current setting for all of the configurable parameters.

-convert

Controls the setting of the UNIX group and other mode bits on AFS files and directories exported to the non-AFS file system. If the value is on, they are set to match the owner mode bits. If the value is off, the bits are not changed. If this argument is omitted, the default value is on.

-uidcheck

Controls whether tokens can be placed in a credential structure identified by a UID that differs from the local UID of the entity that is placing the tokens in the structure.

If the value is on, the UID that identifies the credential structure must match the local UID.
With respect to the knfs command, this value means that the value of -id argument must match the issuer's local UID on the translator machine. In practice, this setting makes it pointless to include the -id argument to the knfs command, because the only acceptable value (the issuer's local UID) is already used when the -id argument is omitted.
Enabling UID checking also makes it impossible to issue the klog and pagsh commands on a client machine of the non-AFS file system even though it is a system type supported by AFS. For an explanation, see the reference page for the klog command.
If the value is off (the default), tokens can be assigned to a local UID in the non-AFS file system that does not match the local UID of the entity assigning the tokens.
With respect to the knfs command, it means that the issuer can use the -id argument to assign tokens to a local UID on the NFS client machine that does not match his or her local UID on the translator machine. (An example is assigning tokens to the MFS client machine's local superuser root.) This setting allows more than one issuer of the knfs command to make tokens available to the same user on the NFS client machine. Each time a different user issues the knfs command with the same value for the -id argument, that user's tokens overwrite the existing ones. This can result in unpredictable access for the user on the NFS client machine.

-submounts

Controls whether a user of the non-AFS filesystem can mount any directory in the AFS filespace other than the top-level /afs directory. If the value is on, such submounts are allowed. If the value is off, only mounts of the /afs directory are allowed. If this argument is omitted, the default value is off.

-help

Prints the online help for this command. All other valid options are ignored.

Output

If the machine is not even configured as a server of the non-AFS file system, the following message appears:

   Sorry, the file_system-exporter type is currently not supported on
   this AFS client

If the machine is configured as a server of the non-AFS file system but is not currently enabled to reexport AFS to it (because the -start argument to this command is not set to on), the message is as follows:

   'file_system' translator is disabled

If the machine is enabled to reexport AFS, the following message precedes messages that report the settings of the other parameters.

   'file_system' translator is enabled with the following options:

The following messages indicate that the -convert argument is set to on or off respectively:

   Running in convert owner mode bits to world/other mode
   Running in strict unix mode

The following messages indicate that the -uidcheck argument is set to on or off respectively:

   Running in strict 'passwd sync' mode
   Running in no 'passwd sync' mode

The following messages indicate that the -submounts argument is set to on or off respectively:

   Allow mounts of /afs/.. subdirs
   Only mounts to /afs allowed

Examples

The following example shows that the local machine can export AFS to NFS client machines.

   % fs exportafs nfs
   'nfs' translator is enabled with the following options:
        Running in convert owner mode bits to world/other mode
        Running in no 'passwd sync' mode
        Only mounts to /afs allowed

The following example enables the machine as an NFS server and converts the UNIX group and other mode bits on exported AFS directories and files to match the UNIX owner mode bits.

   % fs exportafs -type nfs -start on -convert on

The following example disables the machine from reexporting AFS to NFS client machines:

   % fs exportafs -type nfs -start off

Privilege Required

The issuer must be logged in as the local superuser root.

Related Information

klog

knfs