Documentation: nfs: idmapper: convert to ReST

Convert idmapper.txt to ReST and move it to admin-guide.
Content remains mostly unchanged otherwise.

Signed-off-by: Daniel W. S. Almeida <dwlsalmeida@gmail.com>
Link: https://lore.kernel.org/r/069e40cd551ea778538f8fe9ad15ee26e45fc748.1578697871.git.dwlsalmeida@gmail.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

1 files changed, 0 insertions, 75 deletions

diff --git a/Documentation/filesystems/nfs/idmapper.txt b/Documentation/filesystems/nfs/idmapper.txt
deleted file mode 100644
index b86831acd583..000000000000
--- a/Documentation/filesystems/nfs/idmapper.txt
+++ /dev/null
@@ -1,75 +0,0 @@
-
-=========
-ID Mapper
-=========
-Id mapper is used by NFS to translate user and group ids into names, and to
-translate user and group names into ids.  Part of this translation involves
-performing an upcall to userspace to request the information.  There are two
-ways NFS could obtain this information: placing a call to /sbin/request-key
-or by placing a call to the rpc.idmap daemon.
-
-NFS will attempt to call /sbin/request-key first.  If this succeeds, the
-result will be cached using the generic request-key cache.  This call should
-only fail if /etc/request-key.conf is not configured for the id_resolver key
-type, see the "Configuring" section below if you wish to use the request-key
-method.
-
-If the call to /sbin/request-key fails (if /etc/request-key.conf is not
-configured with the id_resolver key type), then the idmapper will ask the
-legacy rpc.idmap daemon for the id mapping.  This result will be stored
-in a custom NFS idmap cache.
-
-
-===========
-Configuring
-===========
-The file /etc/request-key.conf will need to be modified so /sbin/request-key can
-direct the upcall.  The following line should be added:
-
-#OP	TYPE	DESCRIPTION	CALLOUT INFO	PROGRAM ARG1 ARG2 ARG3 ...
-#======	=======	===============	===============	===============================
-create	id_resolver	*	*		/usr/sbin/nfs.idmap %k %d 600
-
-This will direct all id_resolver requests to the program /usr/sbin/nfs.idmap.
-The last parameter, 600, defines how many seconds into the future the key will
-expire.  This parameter is optional for /usr/sbin/nfs.idmap.  When the timeout
-is not specified, nfs.idmap will default to 600 seconds.
-
-id mapper uses for key descriptions:
-	  uid:  Find the UID for the given user
-	  gid:  Find the GID for the given group
-	 user:  Find the user  name for the given UID
-	group:  Find the group name for the given GID
-
-You can handle any of these individually, rather than using the generic upcall
-program.  If you would like to use your own program for a uid lookup then you
-would edit your request-key.conf so it look similar to this:
-
-#OP	TYPE	DESCRIPTION	CALLOUT INFO	PROGRAM ARG1 ARG2 ARG3 ...
-#======	=======	===============	===============	===============================
-create	id_resolver	uid:*	*		/some/other/program %k %d 600
-create	id_resolver	*	*		/usr/sbin/nfs.idmap %k %d 600
-
-Notice that the new line was added above the line for the generic program.
-request-key will find the first matching line and corresponding program.  In
-this case, /some/other/program will handle all uid lookups and
-/usr/sbin/nfs.idmap will handle gid, user, and group lookups.
-
-See <file:Documentation/security/keys/request-key.rst> for more information
-about the request-key function.
-
-
-=========
-nfs.idmap
-=========
-nfs.idmap is designed to be called by request-key, and should not be run "by
-hand".  This program takes two arguments, a serialized key and a key
-description.  The serialized key is first converted into a key_serial_t, and
-then passed as an argument to keyctl_instantiate (both are part of keyutils.h).
-
-The actual lookups are performed by functions found in nfsidmap.h.  nfs.idmap
-determines the correct function to call by looking at the first part of the
-description string.  For example, a uid lookup description will appear as
-"uid:user@domain".
-
-nfs.idmap will return 0 if the key was instantiated, and non-zero otherwise.