[PATCH 3.14 55/98] NFSv4.1: Fix client id trunking on Linux

Greg Kroah-Hartman
2015-01-25T19:16:57Z

From: Trond Myklebust <trond.myklebust@primarydata.com>

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@oracle.com>
Tested-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
fs/nfs/nfs4client.c | 17 ++++++++---------
1 file changed, 8 insertions(+), 9 deletions(-)

--- a/fs/nfs/nfs4client.c
+++ b/fs/nfs/nfs4client.c
@@ -565,20 +565,14 @@ static bool nfs4_match_clientids(struct
}

/*
- * 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)
@@ -654,7 +648,12 @@ int nfs41_walk_client_list(struct nfs_cl
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);