[3.13.y-ckt stable] Patch "NFSv4.1: Fix client id trunking on Linux" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    NFSv4.1: Fix client id trunking on Linux

to the linux-3.13.y-queue branch of the 3.13.y-ckt extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.13.y-queue

This patch is scheduled to be released in version 3.13.11-ckt16.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.13.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 2211a8045b6c50b7c1af88e3b9f8d6469d4afed8 Mon Sep 17 00:00:00 2001
From: Trond Myklebust <trond.myklebust at primarydata.com>
Date: Fri, 2 Jan 2015 16:25:08 -0500
Subject: NFSv4.1: Fix client id trunking on Linux

commit 1fc0703af3143914a389bfa081c7acb09502ed5d upstream.

Currently, our trunking code will check for session trunking, but will
fail to detect client id trunking. This is a problem, because it means
that the client will fail to recognise that the two connections represent
shared state, even if they do not permit a shared session.
By removing the check for the server minor id, and only checking the
major id, we will end up doing the right thing in both cases: we close
down the new nfs_client and fall back to using the existing one.

Fixes: 05f4c350ee02e ("NFS: Discover NFSv4 server trunking when mounting")
Cc: Chuck Lever <chuck.lever at oracle.com>
Tested-by: Chuck Lever <chuck.lever at oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust at primarydata.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 fs/nfs/nfs4client.c | 17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)

diff --git a/fs/nfs/nfs4client.c b/fs/nfs/nfs4client.c
index af6013c..14c8af6 100644
--- a/fs/nfs/nfs4client.c
+++ b/fs/nfs/nfs4client.c
@@ -568,20 +568,14 @@ static bool nfs4_match_clientids(struct nfs_client *a, struct nfs_client *b)
 }

 /*
- * Returns true if the server owners match
+ * Returns true if the server major ids match
  */
 static bool
-nfs4_match_serverowners(struct nfs_client *a, struct nfs_client *b)
+nfs4_check_clientid_trunking(struct nfs_client *a, struct nfs_client *b)
 {
 	struct nfs41_server_owner *o1 = a->cl_serverowner;
 	struct nfs41_server_owner *o2 = b->cl_serverowner;

-	if (o1->minor_id != o2->minor_id) {
-		dprintk("NFS: --> %s server owner minor IDs do not match\n",
-			__func__);
-		return false;
-	}
-
 	if (o1->major_id_sz != o2->major_id_sz)
 		goto out_major_mismatch;
 	if (memcmp(o1->major_id, o2->major_id, o1->major_id_sz) != 0)
@@ -657,7 +651,12 @@ int nfs41_walk_client_list(struct nfs_client *new,
 		if (!nfs4_match_clientids(pos, new))
 			continue;

-		if (!nfs4_match_serverowners(pos, new))
+		/*
+		 * Note that session trunking is just a special subcase of
+		 * client id trunking. In either case, we want to fall back
+		 * to using the existing nfs_client.
+		 */
+		if (!nfs4_check_clientid_trunking(pos, new))
 			continue;

 		atomic_inc(&pos->cl_count);
--
1.9.1