exportfs(8)                                           exportfs(8)

       exportfs - maintain list of NFS exported file systems

       /usr/sbin/exportfs [-av] [-o options,..] [client:/path ..]
       /usr/sbin/exportfs [-rv] [-o options,..] [client:/path ..]
       /usr/sbin/exportfs [-av] -u [client:/path ..]
       /usr/sbin/exportfs [-v]

       The exportfs command is used to maintain the current table
       of exported file systems for NFS. This list is kept  in  a
       separate  file  named  /var/lib/nfs/xtab.   Normally, this
       file is initialized with the  list  of  all  file  systems
       named  in  /etc/exports by invoking exportfs -a, and modi-
       fied by mountd(8) whenever receiving a mount request  from
       a host that is matched by a network or domain export.

       However, administrators can choose to add and delete indi-
       vidual file systems without modifying  /etc/exports  using

       -a     Export or unexport all directories.

       -o options,...
              Specify a list of export options in the same manner
              as in exports(5).

       -r     Reexport   all   directories.    It    synchronizes
              /var/lib/nfs/xtab  with  /etc/exports.  It  removes
              entries in /var/lib/nfs/xtab which are deleted from

       -u     Unexport one or more directories.

       -v     Be  verbose.  When  exporting  or unexporting, show
              what's going on. When displaying the current export
              list, also display the list of export options.

   Exporting Directories
       The  first  synopsis  shows how to invoke the command when
       adding new  entries  to  the  export  table.   When  using
       exportfs  -a,  all  directories in exports(5) are added to
       xtab and the resulting list is pushed into the kernel.

       The host:/path argument specifies the directory to  export
       along  with the host or hosts to export it to. All formats
       described in exports(5) are supported; to export a  direc-
       tory to the world, simply specify /path.

       The  export  options  for a particular host/directory pair
       derive from several sources.  The set of  default  options
       can  be  overridden  by  entries  in  /usr/etc/exports and
       /var/lib/nfs/xtab,  if  they  exists.   In  addition,  the
       administrator  may  overide any options from these sources
       using the -o argument which takes a  comma-separated  list
       of  options  in the same fashion as one would specify them
       in exports(5).  Thus, exportfs can also be used to  modify
       the export options of an already exported directory.

       Modifications  of  the kernel export table used by nfsd(8)
       take place immediately after parsing the command line  and
       updating the xtab file.

   Unexporting Directories
       The  second  synopsis  shows how to unexported a currently
       exported directory.  When using exportfs -ua, all  entries
       listed  in xtab are removed from the kernel export tables,
       and the file is cleared. This effectively shuts  down  all
       NFS activity.

       To  remove  individial  export  entries, one can specify a
       host:/path pair. This deletes  the  specified  entry  from
       xtab and removes the corresponding kernel entry.

   Dumping the Export Table
       Invoking  exportfs  without further options shows the cur-
       rent list of exported file systems.  When  giving  the  -v
       option,  the  list  of flags pertaining to each export are
       shown in addition.

       The following adds all directories listed in  /etc/exports
       to  /var/lib/nfs/xtab  and  pushes  the  resulting  export
       entries into the kernel:

       # exportfs -a

       To export the /usr/tmp directory to host djando,  allowing
       asynchronous writes, one would do this:

       # exportfs django:/usr/tmp -o async

       If the directory was already exported,

       Exporting  to  IP  networks,  DNS and NIS domains does not
       enable clients from these groups  to  access  NFS  immedi-
       ately;  rather,  these  sorts  of  exports  are  hints  to
       mountd(8) to grant any mount requests from these  clients.
       This  is  usually  not a big problem, because any existing
       mounts are preserved in xtab across reboots.

       When unexporting a network or domain  entry,  any  current
       exports  to members of this group are unaffected. The rea-
       son for this is that exportfs cannot  tell  whether  these
       specific  exports  were  created  as a result of the group
       export, or whether they have been exported  independently.

       exports(5), mountd(8)

       Olaf Kirch, <okir@monad.swb.de>

                           15 Feb 1996                          1