ocfs2: Pass the locking protocol into ocfs2_cluster_connect().

Inside the stackglue, the locking protocol structure is hanging off of
the ocfs2_cluster_connection.  This takes it one further; the locking
protocol is passed into ocfs2_cluster_connect().  Now different cluster
connections can have different locking protocols with distinct asts.
Note that all locking protocols have to keep their maximum protocol
version in lock-step.

With the protocol structure set in ocfs2_cluster_connect(), there is no
need for the stackglue to have a static pointer to a specific protocol
structure.  We can change initialization to only pass in the maximum
protocol version.

Signed-off-by: Joel Becker <joel.becker@oracle.com>

1 files changed, 25 insertions, 18 deletions

diff --git a/fs/ocfs2/stackglue.c b/fs/ocfs2/stackglue.c
index fc184c762700..31db2e87cfd4 100644
--- a/fs/ocfs2/stackglue.c
+++ b/fs/ocfs2/stackglue.c
@@ -36,7 +36,7 @@
 #define OCFS2_STACK_PLUGIN_USER         "user"
 #define OCFS2_MAX_HB_CTL_PATH           256
 
-static struct ocfs2_locking_protocol *lproto;
+static struct ocfs2_protocol_version locking_max_version;
 static DEFINE_SPINLOCK(ocfs2_stack_lock);
 static LIST_HEAD(ocfs2_stack_list);
 static char cluster_stack_name[OCFS2_STACK_LABEL_LEN + 1];
@@ -176,7 +176,7 @@ int ocfs2_stack_glue_register(struct ocfs2_stack_plugin *plugin)
         spin_lock(&ocfs2_stack_lock);
         if (!ocfs2_stack_lookup(plugin->sp_name)) {
                 plugin->sp_count = 0;
-                plugin->sp_max_proto = lproto->lp_max_version;
+                plugin->sp_max_proto = locking_max_version;
                 list_add(&plugin->sp_list, &ocfs2_stack_list);
                 printk(KERN_INFO "ocfs2: Registered cluster interface %s\n",
                        plugin->sp_name);
@@ -213,23 +213,23 @@ void ocfs2_stack_glue_unregister(struct ocfs2_stack_plugin *plugin)
 }
 EXPORT_SYMBOL_GPL(ocfs2_stack_glue_unregister);
 
-void ocfs2_stack_glue_set_locking_protocol(struct ocfs2_locking_protocol *proto)
+void ocfs2_stack_glue_set_max_proto_version(struct ocfs2_protocol_version *max_proto)
 {
         struct ocfs2_stack_plugin *p;
 
-        BUG_ON(proto == NULL);
-
         spin_lock(&ocfs2_stack_lock);
-        BUG_ON(active_stack != NULL);
+        if (memcmp(max_proto, &locking_max_version,
+                   sizeof(struct ocfs2_protocol_version))) {
+                BUG_ON(locking_max_version.pv_major != 0);
 
-        lproto = proto;
-        list_for_each_entry(p, &ocfs2_stack_list, sp_list) {
-                p->sp_max_proto = lproto->lp_max_version;
+                locking_max_version = *max_proto;
+                list_for_each_entry(p, &ocfs2_stack_list, sp_list) {
+                        p->sp_max_proto = locking_max_version;
+                }
         }
-
         spin_unlock(&ocfs2_stack_lock);
 }
-EXPORT_SYMBOL_GPL(ocfs2_stack_glue_set_locking_protocol);
+EXPORT_SYMBOL_GPL(ocfs2_stack_glue_set_max_proto_version);
 
 
 /*
@@ -245,8 +245,6 @@ int ocfs2_dlm_lock(struct ocfs2_cluster_connection *conn,
                    void *name,
                    unsigned int namelen)
 {
-        BUG_ON(lproto == NULL);
-
         if (!lksb->lksb_conn)
                 lksb->lksb_conn = conn;
         else
@@ -260,7 +258,6 @@ int ocfs2_dlm_unlock(struct ocfs2_cluster_connection *conn,
                      struct ocfs2_dlm_lksb *lksb,
                      u32 flags)
 {
-        BUG_ON(lproto == NULL);
         BUG_ON(lksb->lksb_conn == NULL);
 
         return active_stack->sp_ops->dlm_unlock(conn, lksb, flags);
@@ -314,6 +311,7 @@ EXPORT_SYMBOL_GPL(ocfs2_plock);
 int ocfs2_cluster_connect(const char *stack_name,
                           const char *group,
                           int grouplen,
+                          struct ocfs2_locking_protocol *lproto,
                           void (*recovery_handler)(int node_num,
                                                    void *recovery_data),
                           void *recovery_data,
@@ -331,6 +329,12 @@ int ocfs2_cluster_connect(const char *stack_name,
                 goto out;
         }
 
+        if (memcmp(&lproto->lp_max_version, &locking_max_version,
+                   sizeof(struct ocfs2_protocol_version))) {
+                rc = -EINVAL;
+                goto out;
+        }
+
         new_conn = kzalloc(sizeof(struct ocfs2_cluster_connection),
                            GFP_KERNEL);
         if (!new_conn) {
@@ -456,10 +460,10 @@ static ssize_t ocfs2_max_locking_protocol_show(struct kobject *kobj,
         ssize_t ret = 0;
 
         spin_lock(&ocfs2_stack_lock);
-        if (lproto)
+        if (locking_max_version.pv_major)
                 ret = snprintf(buf, PAGE_SIZE, "%u.%u\n",
-                               lproto->lp_max_version.pv_major,
-                               lproto->lp_max_version.pv_minor);
+                               locking_max_version.pv_major,
+                               locking_max_version.pv_minor);
         spin_unlock(&ocfs2_stack_lock);
 
         return ret;
@@ -688,7 +692,10 @@ static int __init ocfs2_stack_glue_init(void)
 
 static void __exit ocfs2_stack_glue_exit(void)
 {
-        lproto = NULL;
+        memset(&locking_max_version, 0,
+               sizeof(struct ocfs2_protocol_version));
+        locking_max_version.pv_major = 0;
+        locking_max_version.pv_minor = 0;
         ocfs2_sysfs_exit();
         if (ocfs2_table_header)
                 unregister_sysctl_table(ocfs2_table_header);