![[Go to CFHT Home Page]](/images/cfht-icon.gif){kind=icon}
Man Pages 
Back to Software Index 
Manpage Top Level
The exportfs command maintains the current table of exports for the NFS server. The master export table is kept in a file named /var/lib/nfs/etab. This file is read by rpc.mountd when a client sends an NFS MOUNT request.
Normally the master export table is initialized with the contents of /etc/exports and files under /etc/exports.d by invoking exportfs -a. However, a system administrator can choose to add or delete exports without modifying /etc/exports or files under /etc/exports.d by using the exportfs command.
exportfs and its partner program rpc.mountd work in one of two modes: a legacy mode which applies to 2.4 and earlier versions of the Linux kernel, and a new mode which applies to 2.6 and later versions, providing the nfsd virtual filesystem has been mounted at /proc/fs/nfsd or /proc/fs/nfs. On 2.6 kernels, if this filesystem is not mounted, the legacy mode is used.
In the new mode, exportfs does not give any information to the kernel, but provides it only to rpc.mountd through the /var/lib/nfs/etab file. rpc.mountd then manages kernel requests for information about exports, as needed.
In the legacy mode, exports which identify a specific host, rather than a subnet or netgroup, are entered directly into the kernel’s export table, as well as being written to /var/lib/nfs/etab. Further, exports listed in /var/lib/nfs/rmtab which match a non host-specific export request will cause an appropriate export entry for the host given in rmtab to be added to the kernel’s export table.
The host:/path argument specifies a local directory to export, along with the client or clients who are permitted to access it. See exports(5) for a description of supported options and access list formats. To export a directory to the world, simply specify :/path.
The export options for a particular host/directory pair derive from several sources. The default export options are sync,ro,root_squash,wdelay. These can be overridden by entries in /etc/exports or files under /etc/exports.d.
A system administrator may override options from these sources using the -o command-line option on exportfs. This option takes a comma-separated list of options in the same fashion as one would specify them in /etc/exports. In this way exportfs can be used to modify the export options of an already exported directory.
To remove an export, specify a host:/path pair. This deletes the specified entry from /var/lib/nfs/etab and removes the corresponding kernel entry (if any).
# exportfs -a
To export the /usr/tmp directory to host django, allowing insecure file locking requests from clients:
# exportfs -o insecure_locks django:/usr/tmp
To unexport the /usr/tmp directory:
# exportfs -u django:/usr/tmp
To unexport all exports listed in /etc/exports and files under /etc/exports.d:
# exportfs -au
When unexporting a network or domain entry, any current exports to members of this group will be checked against the remaining valid exports and if they themselves are no longer valid they will be removed.