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From:   Scott Mayhew <smayhew@redhat.com>
To:     steved@redhat.com
Cc:     linux-nfs@vger.kernel.org
Subject: [nfs-utils PATCH 3/3] nfs(5): Document the trunkdiscovery/notrunkdiscovery mount option.
Date:   Thu,  1 Jun 2023 15:46:17 -0400
Message-Id: <20230601194617.2174639-4-smayhew@redhat.com>
In-Reply-To: <20230601194617.2174639-1-smayhew@redhat.com>
References: <20230601194617.2174639-1-smayhew@redhat.com>
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Also, move the documentation for max_connect to the section for
NFSv4-specific options.

Signed-off-by: Scott Mayhew <smayhew@redhat.com>
---
 utils/mount/nfs.man | 39 ++++++++++++++++++++++++++-------------
 1 file changed, 26 insertions(+), 13 deletions(-)

diff --git a/utils/mount/nfs.man b/utils/mount/nfs.man
index 2ed898f8..0b976731 100644
--- a/utils/mount/nfs.man
+++ b/utils/mount/nfs.man
@@ -423,19 +423,6 @@ Note that the
 option may also be used by some pNFS drivers to decide how many
 connections to set up to the data servers.
 .TP 1.5i
-.BR max_connect= n
-While
-.BR nconnect
-option sets a limit on the number of connections that can be established
-to a given server IP,
-.BR max_connect
-option allows the user to specify maximum number of connections to different
-server IPs that belong to the same NFSv4.1+ server (session trunkable
-connections) up to a limit of 16. When client discovers that it established
-a client ID to an already existing server, instead of dropping the newly
-created network transport, the client will add this new connection to the
-list of available transports for that RPC client.
-.TP 1.5i
 .BR rdirplus " / " nordirplus
 Selects whether to use NFS v3 or v4 READDIRPLUS requests.
 If this option is not specified, the NFS client uses READDIRPLUS requests
@@ -1000,6 +987,32 @@ when it identifies itself via a traditional identification string.
 .IP
 This mount option has no effect with NFSv4 minor versions newer than zero,
 which always use TSM-compatible client identification strings.
+.TP 1.5i
+.BR max_connect= n
+While
+.BR nconnect
+option sets a limit on the number of connections that can be established
+to a given server IP,
+.BR max_connect
+option allows the user to specify maximum number of connections to different
+server IPs that belong to the same NFSv4.1+ server (session trunkable
+connections) up to a limit of 16. When client discovers that it established
+a client ID to an already existing server, instead of dropping the newly
+created network transport, the client will add this new connection to the
+list of available transports for that RPC client.
+.TP 1.5i
+.BR trunkdiscovery " / " notrunkdiscovery
+When the client discovers a new filesystem on a NFSv4.1+ server, the
+.BR trunkdiscovery
+mount option will cause it to send a GETATTR for the fs_locations attribute.
+If is receives a non-zero length reply, it will iterate through the response,
+and for each server location it will establish a connection, send an
+EXCHANGE_ID, and test for session trunking.  If the trunking test succeeds,
+the connection will be added to the existing set of transports for the server,
+subject to the limit specified by the
+.BR max_connect
+option.  The default is
+.BR notrunkdiscovery .
 .SH nfs4 FILE SYSTEM TYPE
 The
 .BR nfs4
-- 
2.39.2