[PATCH v2 1/8] Documentation: convert nfs.txt to ReST

Daniel W. S. Almeida
2019-12-30T04:56:20Z

This patch converts nfs.txt to RST. It also moves it to admin-guide.
The reason for moving it is because this document contains information
useful for system administrators, as noted on the following paragraph:

'The purpose of this document is to provide information on some of the
special features of the NFS client that can be configured by system
administrators'.

Signed-off-by: Daniel W. S. Almeida <dwlsalmeida@gmail.com>
---
Documentation/admin-guide/index.rst | 1 +
Documentation/admin-guide/nfs/index.rst | 9 ++
.../nfs/nfs-client.rst} | 91 ++++++++++---------
3 files changed, 58 insertions(+), 43 deletions(-)
create mode 100644 Documentation/admin-guide/nfs/index.rst
rename Documentation/{filesystems/nfs/nfs.txt => admin-guide/nfs/nfs-client.rst} (72%)

diff --git a/Documentation/admin-guide/index.rst b/Documentation/admin-guide/index.rst
index 4405b7485312..4433f3929481 100644
--- a/Documentation/admin-guide/index.rst
+++ b/Documentation/admin-guide/index.rst
@@ -76,6 +76,7 @@ configure specific aspects of kernel behavior to your liking.
device-mapper/index
efi-stub
ext4
+ nfs/index
gpio/index
highuid
hw_random
diff --git a/Documentation/admin-guide/nfs/index.rst b/Documentation/admin-guide/nfs/index.rst
new file mode 100644
index 000000000000..f5c0180f4e5e
--- /dev/null
+++ b/Documentation/admin-guide/nfs/index.rst
@@ -0,0 +1,9 @@
+=============
+NFS
+=============
+
+.. toctree::
+ :maxdepth: 1
+
+ nfs-client
+
diff --git a/Documentation/filesystems/nfs/nfs.txt b/Documentation/admin-guide/nfs/nfs-client.rst
similarity index 72%
rename from Documentation/filesystems/nfs/nfs.txt
rename to Documentation/admin-guide/nfs/nfs-client.rst
index f2571c8bef74..f01bf6a6c207 100644
--- a/Documentation/filesystems/nfs/nfs.txt
+++ b/Documentation/admin-guide/nfs/nfs-client.rst
@@ -1,3 +1,6 @@
+==========
+NFS Client
+==========

The NFS client
==============
@@ -59,10 +62,11 @@ The DNS resolver

NFSv4 allows for one server to refer the NFS client to data that has been
migrated onto another server by means of the special "fs_locations"
-attribute. See
- http://tools.ietf.org/html/rfc3530#section-6
-and
- http://tools.ietf.org/html/draft-ietf-nfsv4-referrals-00
+attribute. See `RFC3530 Section 6: Filesystem Migration and Replication`_ and
+`Implementation Guide for Referrals in NFSv4`_.
+
+.. _RFC3530 Section 6\: Filesystem Migration and Replication: http://tools.ietf.org/html/rfc3530#section-6
+.. _Implementation Guide for Referrals in NFSv4: http://tools.ietf.org/html/draft-ietf-nfsv4-referrals-00

The fs_locations information can take the form of either an ip address and
a path, or a DNS hostname and a path. The latter requires the NFS client to
@@ -72,16 +76,16 @@ upcall to allow userland to provide this service.
Assuming that the user has the 'rpc_pipefs' filesystem mounted in the usual
/var/lib/nfs/rpc_pipefs, the upcall consists of the following steps:

- (1) The process checks the dns_resolve cache to see if it contains a
+ #. The process checks the dns_resolve cache to see if it contains a
valid entry. If so, it returns that entry and exits.

- (2) If no valid entry exists, the helper script '/sbin/nfs_cache_getent'
+ #. If no valid entry exists, the helper script '/sbin/nfs_cache_getent'
(may be changed using the 'nfs.cache_getent' kernel boot parameter)
is run, with two arguments:
- - the cache name, "dns_resolve"
- - the hostname to resolve
+ - the cache name, "dns_resolve"
+ - the hostname to resolve

- (3) After looking up the corresponding ip address, the helper script
+ #. After looking up the corresponding ip address, the helper script
writes the result into the rpc_pipefs pseudo-file
'/var/lib/nfs/rpc_pipefs/cache/dns_resolve/channel'
in the following (text) format:
@@ -94,43 +98,44 @@ Assuming that the user has the 'rpc_pipefs' filesystem mounted in the usual
script, and <ttl> is the 'time to live' of this cache entry (in
units of seconds).

- Note: If <ip address> is invalid, say the string "0", then a negative
- entry is created, which will cause the kernel to treat the hostname
- as having no valid DNS translation.
+ .. note::
+ If <ip address> is invalid, say the string "0", then a negative
+ entry is created, which will cause the kernel to treat the hostname
+ as having no valid DNS translation.

A basic sample /sbin/nfs_cache_getent
=====================================
-
-#!/bin/bash
-#
-ttl=600
-#
-cut=/usr/bin/cut
-getent=/usr/bin/getent
-rpc_pipefs=/var/lib/nfs/rpc_pipefs
-#
-die()
-{
- echo "Usage: $0 cache_name entry_name"
- exit 1
-}
-
-[ $# -lt 2 ] && die
-cachename="$1"
-cache_path=${rpc_pipefs}/cache/${cachename}/channel
-
-case "${cachename}" in
- dns_resolve)
- name="$2"
- result="$(${getent} hosts ${name} | ${cut} -f1 -d\ )"
- [ -z "${result}" ] && result="0"
- ;;
- *)
- die
- ;;
-esac
-echo "${result} ${name} ${ttl}" >${cache_path}
-
+.. code-block:: sh
+
+ #!/bin/bash
+ #
+ ttl=600
+ #
+ cut=/usr/bin/cut
+ getent=/usr/bin/getent
+ rpc_pipefs=/var/lib/nfs/rpc_pipefs
+ #
+ die()
+ {
+ echo "Usage: $0 cache_name entry_name"
+ exit 1
+ }
+
+ [ $# -lt 2 ] && die
+ cachename="$1"
+ cache_path=${rpc_pipefs}/cache/${cachename}/channel
+
+ case "${cachename}" in
+ dns_resolve)
+ name="$2"
+ result="$(${getent} hosts ${name} | ${cut} -f1 -d\ )"
+ [ -z "${result}" ] && result="0"
+ ;;
+ *)
+ die
+ ;;
+ esac
+ echo "${result} ${name} ${ttl}" >${cache_path}
--
2.24.1