mount.nfs: Update description of clientaddr= in nfs(5)

[nfs-utils.git] / utils / mount / nfs.man

diff --git a/utils/mount/nfs.man b/utils/mount/nfs.man
index 614de46764fa19f1a23ee9374f79f9c24eff266d..d92da1905a74a64cdc882e93ac90176abcacce52 100644 (file)
--- a/utils/mount/nfs.man
+++ b/utils/mount/nfs.man
@@ -195,11 +195,18 @@ many other operating systems.
 .TP 1.5i
 .I nolock
 Disable NFS locking. Do not start lockd.
 .TP 1.5i
 .I nolock
 Disable NFS locking. Do not start lockd.

-This has to be used with some old NFS servers
-that don't support locking.  Note that applications can
-still get locks on files, but the locks only provide exclusion
-locally.  Other clients mounting the same filesystem
-will not be able to detect the locks.
+This is appropriate for mounting the root filesystem or
+.B /usr
+or
+.BR /var .
+These filesystems are typically either read-only or not shared, and in
+those cases, remote locking is not needed.
+This also needs to be used with some old NFS servers
+that don't support locking.
+.br
+Note that applications can still get locks on files, but the locks
+only provide exclusion locally.  Other clients mounting the same
+filesystem will not be able to detect the locks.

 .TP 1.5i
 .I bg
 If the first NFS mount attempt times out, retry the mount
 .TP 1.5i
 .I bg
 If the first NFS mount attempt times out, retry the mount


@@ -276,6 +283,28 @@ support UDP.
 .TP 1.5i
 .I udp
 Mount the NFS filesystem using the UDP protocol.
 .TP 1.5i
 .I udp
 Mount the NFS filesystem using the UDP protocol.

+.TP 1.5i
+.I nordirplus
+Disables NFSv3 READDIRPLUS RPCs. Use this option when
+mounting servers that don't support or have broken
+READDIRPLUS implementations.
+.TP 1.5i
+.I nosharecache
+As of kernel 2.6.18, it is no longer possible to mount the same
+same filesystem with different mount options to a new mountpoint.
+It was deemed unsafe to do so, since cached data cannot be shared
+between the two mountpoints. In consequence, files or directories
+that were common to both mountpoint subtrees could often be seen to
+be out of sync following an update.
+.br
+This option allows administrators to select the pre-2.6.18 behaviour,
+permitting the same filesystem to be mounted with different mount
+options.
+.br
+.B Beware:
+Use of this option is not recommended unless you are certain that there
+are no hard links or subtrees of this mountpoint that are mounted
+elsewhere.

 .P
 All of the non-value options have corresponding nooption forms.
 For example, nointr means don't allow file operations to be
 .P
 All of the non-value options have corresponding nooption forms.
 For example, nointr means don't allow file operations to be


@@ -382,11 +411,23 @@ Valid protocol types are
 and
 .IR tcp .
 .TP 1.5i
 and
 .IR tcp .
 .TP 1.5i

-.I clientaddr=n
-On a multi-homed client, this
-causes the client to use a specific callback address when
-communicating with an NFS version 4 server.
-This option is currently ignored.
+.I clientaddr=n.n.n.n
+Specifies a single IPv4 address in dotted-quad form that
+the NFS client advertises to allow servers to perform
+NFSv4 callback requests against files on this mount point.
+If the server is not able to establish callback connections
+to clients, performance may degrade, or accesses to
+files may temporarily hang.
+.IP
+If this option is not specified, the
+.BR mount (8)
+command attempts to discover an appropriate callback
+address automatically.
+The automatic discovery process is not perfect, however.
+In the presence of multiple client network interfaces, special
+routing policies, or atypical network topologies, the exact
+address to use for callbacks may be nontrivial to determine,
+and should be explicitly set using this mount option.

 .TP 1.5i
 .I sec=mode
 Same as \f3sec=mode\f1 for the nfs filesystem type (see above).
 .TP 1.5i
 .I sec=mode
 Same as \f3sec=mode\f1 for the nfs filesystem type (see above).


@@ -432,6 +473,23 @@ This extracts a
 server performance penalty but it allows two different NFS clients
 to get reasonable good results when both clients are actively
 writing to common filesystem on the server.
 server performance penalty but it allows two different NFS clients
 to get reasonable good results when both clients are actively
 writing to common filesystem on the server.

+.TP 1.5i
+.I nosharecache
+As of kernel 2.6.18, it is no longer possible to mount the same
+same filesystem with different mount options to a new mountpoint.
+It was deemed unsafe to do so, since cached data cannot be shared
+between the two mountpoints. In consequence, files or directories
+that were common to both mountpoint subtrees could often be seen to
+be out of sync following an update.
+.br
+This option allows administrators to select the pre-2.6.18 behaviour,
+permitting the same filesystem to be mounted with different mount
+options.
+.br
+.B Beware:
+Use of this option is not recommended unless you are certain that there
+are no hard links or subtrees of this mountpoint that are mounted
+elsewhere.

 .P
 All of the non-value options have corresponding nooption forms.
 For example, nointr means don't allow file operations to be
 .P
 All of the non-value options have corresponding nooption forms.
 For example, nointr means don't allow file operations to be