[pnfs] [RFC 19/85] nfs41: share client sessions across mounts

[Benny Halevy]

From: Andy Adamson <andros at netapp.com>

Do not create a new session for each new mount (FSID).

Call nfs4_get_session to bump the reference count for each cloned nfs4 server
which now share the struct nfs_client session.

nfs41: check minorversion on nfs41_get_session

Signed-off-by: Andy Adamson<andros at netapp.com>
Signed-off-by: Benny Halevy <bhalevy at panasas.com>
---
 fs/nfs/client.c   |    4 ++++
 fs/nfs/nfs4_fs.h  |    1 +
 fs/nfs/nfs4proc.c |    5 +++++
 3 files changed, 10 insertions(+), 0 deletions(-)

diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index 80091dc..62bdf31 100644
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -1336,6 +1336,10 @@ struct nfs_server *nfs_clone_server(struct nfs_server *source,
 	if (!IS_ERR(source->client_acl))
 		nfs_init_server_aclclient(server);
 
+#ifdef CONFIG_NFS_V4_1
+	nfs4_get_session(server->nfs_client);
+#endif /* CONFIG_NFS_V4_1 */
+
 	/* probe the filesystem info for this server filesystem */
 	error = nfs_probe_fsinfo(server, fh, &fattr_fsinfo);
 	if (error < 0)
diff --git a/fs/nfs/nfs4_fs.h b/fs/nfs/nfs4_fs.h
index 4b13945..a28427f 100644
--- a/fs/nfs/nfs4_fs.h
+++ b/fs/nfs/nfs4_fs.h
@@ -190,6 +190,7 @@ extern struct nfs4_state_recovery_ops nfs4_reboot_recovery_ops;
 extern struct nfs4_state_recovery_ops nfs4_network_partition_recovery_ops;
 #if defined(CONFIG_NFS_V4_1)
 extern void nfs4_put_session(struct nfs4_session **session);
+extern void nfs4_get_session(struct nfs_client *clp);
 extern struct nfs4_session *nfs4_alloc_session(void);
 #endif /* CONFIG_NFS_V4_1 */
 
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 8e373e9..d0b6ca1 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -3712,6 +3712,11 @@ void nfs4_put_session(struct nfs4_session **session)
 	dprintk("<-- nfs4_put_session()\n");
 }
 
+void nfs4_get_session(struct nfs_client *clp)
+{
+	if (clp->cl_minorversion == 1)
+		atomic_inc(&clp->cl_session->ref_count);
+}
 #endif /* CONFIG_NFS_V4_1 */
 
 struct nfs4_state_recovery_ops nfs4_reboot_recovery_ops = {
-- 
1.6.0.2