1 files changed, 568 insertions, 0 deletions

diff --git a/fs/ocfs2/stackglue.c b/fs/ocfs2/stackglue.c
new file mode 100644
index 000000000000..119f60cea9cc
--- /dev/null
+++ b/fs/ocfs2/stackglue.c
@@ -0,0 +1,568 @@
+/* -*- mode: c; c-basic-offset: 8; -*-
+ * vim: noexpandtab sw=8 ts=8 sts=0:
+ *
+ * stackglue.c
+ *
+ * Code which implements an OCFS2 specific interface to underlying
+ * cluster stacks.
+ *
+ * Copyright (C) 2007 Oracle.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License as published by the Free Software Foundation, version 2.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ */
+
+#include <linux/list.h>
+#include <linux/spinlock.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/kmod.h>
+#include <linux/fs.h>
+#include <linux/kobject.h>
+#include <linux/sysfs.h>
+
+#include "ocfs2_fs.h"
+
+#include "stackglue.h"
+
+#define OCFS2_STACK_PLUGIN_O2CB         "o2cb"
+#define OCFS2_STACK_PLUGIN_USER         "user"
+
+static struct ocfs2_locking_protocol *lproto;
+static DEFINE_SPINLOCK(ocfs2_stack_lock);
+static LIST_HEAD(ocfs2_stack_list);
+static char cluster_stack_name[OCFS2_STACK_LABEL_LEN + 1];
+
+/*
+ * The stack currently in use.  If not null, active_stack->sp_count > 0,
+ * the module is pinned, and the locking protocol cannot be changed.
+ */
+static struct ocfs2_stack_plugin *active_stack;
+
+static struct ocfs2_stack_plugin *ocfs2_stack_lookup(const char *name)
+{
+        struct ocfs2_stack_plugin *p;
+
+        assert_spin_locked(&ocfs2_stack_lock);
+
+        list_for_each_entry(p, &ocfs2_stack_list, sp_list) {
+                if (!strcmp(p->sp_name, name))
+                        return p;
+        }
+
+        return NULL;
+}
+
+static int ocfs2_stack_driver_request(const char *stack_name,
+                                      const char *plugin_name)
+{
+        int rc;
+        struct ocfs2_stack_plugin *p;
+
+        spin_lock(&ocfs2_stack_lock);
+
+        /*
+         * If the stack passed by the filesystem isn't the selected one,
+         * we can't continue.
+         */
+        if (strcmp(stack_name, cluster_stack_name)) {
+                rc = -EBUSY;
+                goto out;
+        }
+
+        if (active_stack) {
+                /*
+                 * If the active stack isn't the one we want, it cannot
+                 * be selected right now.
+                 */
+                if (!strcmp(active_stack->sp_name, plugin_name))
+                        rc = 0;
+                else
+                        rc = -EBUSY;
+                goto out;
+        }
+
+        p = ocfs2_stack_lookup(plugin_name);
+        if (!p || !try_module_get(p->sp_owner)) {
+                rc = -ENOENT;
+                goto out;
+        }
+
+        /* Ok, the stack is pinned */
+        p->sp_count++;
+        active_stack = p;
+
+        rc = 0;
+
+out:
+        spin_unlock(&ocfs2_stack_lock);
+        return rc;
+}
+
+/*
+ * This function looks up the appropriate stack and makes it active.  If
+ * there is no stack, it tries to load it.  It will fail if the stack still
+ * cannot be found.  It will also fail if a different stack is in use.
+ */
+static int ocfs2_stack_driver_get(const char *stack_name)
+{
+        int rc;
+        char *plugin_name = OCFS2_STACK_PLUGIN_O2CB;
+
+        /*
+         * Classic stack does not pass in a stack name.  This is
+         * compatible with older tools as well.
+         */
+        if (!stack_name || !*stack_name)
+                stack_name = OCFS2_STACK_PLUGIN_O2CB;
+
+        if (strlen(stack_name) != OCFS2_STACK_LABEL_LEN) {
+                printk(KERN_ERR
+                       "ocfs2 passed an invalid cluster stack label: \"%s\"\n",
+                       stack_name);
+                return -EINVAL;
+        }
+
+        /* Anything that isn't the classic stack is a user stack */
+        if (strcmp(stack_name, OCFS2_STACK_PLUGIN_O2CB))
+                plugin_name = OCFS2_STACK_PLUGIN_USER;
+
+        rc = ocfs2_stack_driver_request(stack_name, plugin_name);
+        if (rc == -ENOENT) {
+                request_module("ocfs2_stack_%s", plugin_name);
+                rc = ocfs2_stack_driver_request(stack_name, plugin_name);
+        }
+
+        if (rc == -ENOENT) {
+                printk(KERN_ERR
+                       "ocfs2: Cluster stack driver \"%s\" cannot be found\n",
+                       plugin_name);
+        } else if (rc == -EBUSY) {
+                printk(KERN_ERR
+                       "ocfs2: A different cluster stack is in use\n");
+        }
+
+        return rc;
+}
+
+static void ocfs2_stack_driver_put(void)
+{
+        spin_lock(&ocfs2_stack_lock);
+        BUG_ON(active_stack == NULL);
+        BUG_ON(active_stack->sp_count == 0);
+
+        active_stack->sp_count--;
+        if (!active_stack->sp_count) {
+                module_put(active_stack->sp_owner);
+                active_stack = NULL;
+        }
+        spin_unlock(&ocfs2_stack_lock);
+}
+
+int ocfs2_stack_glue_register(struct ocfs2_stack_plugin *plugin)
+{
+        int rc;
+
+        spin_lock(&ocfs2_stack_lock);
+        if (!ocfs2_stack_lookup(plugin->sp_name)) {
+                plugin->sp_count = 0;
+                plugin->sp_proto = lproto;
+                list_add(&plugin->sp_list, &ocfs2_stack_list);
+                printk(KERN_INFO "ocfs2: Registered cluster interface %s\n",
+                       plugin->sp_name);
+                rc = 0;
+        } else {
+                printk(KERN_ERR "ocfs2: Stack \"%s\" already registered\n",
+                       plugin->sp_name);
+                rc = -EEXIST;
+        }
+        spin_unlock(&ocfs2_stack_lock);
+
+        return rc;
+}
+EXPORT_SYMBOL_GPL(ocfs2_stack_glue_register);
+
+void ocfs2_stack_glue_unregister(struct ocfs2_stack_plugin *plugin)
+{
+        struct ocfs2_stack_plugin *p;
+
+        spin_lock(&ocfs2_stack_lock);
+        p = ocfs2_stack_lookup(plugin->sp_name);
+        if (p) {
+                BUG_ON(p != plugin);
+                BUG_ON(plugin == active_stack);
+                BUG_ON(plugin->sp_count != 0);
+                list_del_init(&plugin->sp_list);
+                printk(KERN_INFO "ocfs2: Unregistered cluster interface %s\n",
+                       plugin->sp_name);
+        } else {
+                printk(KERN_ERR "Stack \"%s\" is not registered\n",
+                       plugin->sp_name);
+        }
+        spin_unlock(&ocfs2_stack_lock);
+}
+EXPORT_SYMBOL_GPL(ocfs2_stack_glue_unregister);
+
+void ocfs2_stack_glue_set_locking_protocol(struct ocfs2_locking_protocol *proto)
+{
+        struct ocfs2_stack_plugin *p;
+
+        BUG_ON(proto == NULL);
+
+        spin_lock(&ocfs2_stack_lock);
+        BUG_ON(active_stack != NULL);
+
+        lproto = proto;
+        list_for_each_entry(p, &ocfs2_stack_list, sp_list) {
+                p->sp_proto = lproto;
+        }
+
+        spin_unlock(&ocfs2_stack_lock);
+}
+EXPORT_SYMBOL_GPL(ocfs2_stack_glue_set_locking_protocol);
+
+
+/*
+ * The ocfs2_dlm_lock() and ocfs2_dlm_unlock() functions take
+ * "struct ocfs2_lock_res *astarg" instead of "void *astarg" because the
+ * underlying stack plugins need to pilfer the lksb off of the lock_res.
+ * If some other structure needs to be passed as an astarg, the plugins
+ * will need to be given a different avenue to the lksb.
+ */
+int ocfs2_dlm_lock(struct ocfs2_cluster_connection *conn,
+                   int mode,
+                   union ocfs2_dlm_lksb *lksb,
+                   u32 flags,
+                   void *name,
+                   unsigned int namelen,
+                   struct ocfs2_lock_res *astarg)
+{
+        BUG_ON(lproto == NULL);
+
+        return active_stack->sp_ops->dlm_lock(conn, mode, lksb, flags,
+                                              name, namelen, astarg);
+}
+EXPORT_SYMBOL_GPL(ocfs2_dlm_lock);
+
+int ocfs2_dlm_unlock(struct ocfs2_cluster_connection *conn,
+                     union ocfs2_dlm_lksb *lksb,
+                     u32 flags,
+                     struct ocfs2_lock_res *astarg)
+{
+        BUG_ON(lproto == NULL);
+
+        return active_stack->sp_ops->dlm_unlock(conn, lksb, flags, astarg);
+}
+EXPORT_SYMBOL_GPL(ocfs2_dlm_unlock);
+
+int ocfs2_dlm_lock_status(union ocfs2_dlm_lksb *lksb)
+{
+        return active_stack->sp_ops->lock_status(lksb);
+}
+EXPORT_SYMBOL_GPL(ocfs2_dlm_lock_status);
+
+/*
+ * Why don't we cast to ocfs2_meta_lvb?  The "clean" answer is that we
+ * don't cast at the glue level.  The real answer is that the header
+ * ordering is nigh impossible.
+ */
+void *ocfs2_dlm_lvb(union ocfs2_dlm_lksb *lksb)
+{
+        return active_stack->sp_ops->lock_lvb(lksb);
+}
+EXPORT_SYMBOL_GPL(ocfs2_dlm_lvb);
+
+void ocfs2_dlm_dump_lksb(union ocfs2_dlm_lksb *lksb)
+{
+        active_stack->sp_ops->dump_lksb(lksb);
+}
+EXPORT_SYMBOL_GPL(ocfs2_dlm_dump_lksb);
+
+int ocfs2_cluster_connect(const char *stack_name,
+                          const char *group,
+                          int grouplen,
+                          void (*recovery_handler)(int node_num,
+                                                   void *recovery_data),
+                          void *recovery_data,
+                          struct ocfs2_cluster_connection **conn)
+{
+        int rc = 0;
+        struct ocfs2_cluster_connection *new_conn;
+
+        BUG_ON(group == NULL);
+        BUG_ON(conn == NULL);
+        BUG_ON(recovery_handler == NULL);
+
+        if (grouplen > GROUP_NAME_MAX) {
+                rc = -EINVAL;
+                goto out;
+        }
+
+        new_conn = kzalloc(sizeof(struct ocfs2_cluster_connection),
+                           GFP_KERNEL);
+        if (!new_conn) {
+                rc = -ENOMEM;
+                goto out;
+        }
+
+        memcpy(new_conn->cc_name, group, grouplen);
+        new_conn->cc_namelen = grouplen;
+        new_conn->cc_recovery_handler = recovery_handler;
+        new_conn->cc_recovery_data = recovery_data;
+
+        /* Start the new connection at our maximum compatibility level */
+        new_conn->cc_version = lproto->lp_max_version;
+
+        /* This will pin the stack driver if successful */
+        rc = ocfs2_stack_driver_get(stack_name);
+        if (rc)
+                goto out_free;
+
+        rc = active_stack->sp_ops->connect(new_conn);
+        if (rc) {
+                ocfs2_stack_driver_put();
+                goto out_free;
+        }
+
+        *conn = new_conn;
+
+out_free:
+        if (rc)
+                kfree(new_conn);
+
+out:
+        return rc;
+}
+EXPORT_SYMBOL_GPL(ocfs2_cluster_connect);
+
+/* If hangup_pending is 0, the stack driver will be dropped */
+int ocfs2_cluster_disconnect(struct ocfs2_cluster_connection *conn,
+                             int hangup_pending)
+{
+        int ret;
+
+        BUG_ON(conn == NULL);
+
+        ret = active_stack->sp_ops->disconnect(conn, hangup_pending);
+
+        /* XXX Should we free it anyway? */
+        if (!ret) {
+                kfree(conn);
+                if (!hangup_pending)
+                        ocfs2_stack_driver_put();
+        }
+
+        return ret;
+}
+EXPORT_SYMBOL_GPL(ocfs2_cluster_disconnect);
+
+void ocfs2_cluster_hangup(const char *group, int grouplen)
+{
+        BUG_ON(group == NULL);
+        BUG_ON(group[grouplen] != '\0');
+
+        if (active_stack->sp_ops->hangup)
+                active_stack->sp_ops->hangup(group, grouplen);
+
+        /* cluster_disconnect() was called with hangup_pending==1 */
+        ocfs2_stack_driver_put();
+}
+EXPORT_SYMBOL_GPL(ocfs2_cluster_hangup);
+
+int ocfs2_cluster_this_node(unsigned int *node)
+{
+        return active_stack->sp_ops->this_node(node);
+}
+EXPORT_SYMBOL_GPL(ocfs2_cluster_this_node);
+
+
+/*
+ * Sysfs bits
+ */
+
+static ssize_t ocfs2_max_locking_protocol_show(struct kobject *kobj,
+                                               struct kobj_attribute *attr,
+                                               char *buf)
+{
+        ssize_t ret = 0;
+
+        spin_lock(&ocfs2_stack_lock);
+        if (lproto)
+                ret = snprintf(buf, PAGE_SIZE, "%u.%u\n",
+                               lproto->lp_max_version.pv_major,
+                               lproto->lp_max_version.pv_minor);
+        spin_unlock(&ocfs2_stack_lock);
+
+        return ret;
+}
+
+static struct kobj_attribute ocfs2_attr_max_locking_protocol =
+        __ATTR(max_locking_protocol, S_IFREG | S_IRUGO,
+               ocfs2_max_locking_protocol_show, NULL);
+
+static ssize_t ocfs2_loaded_cluster_plugins_show(struct kobject *kobj,
+                                                 struct kobj_attribute *attr,
+                                                 char *buf)
+{
+        ssize_t ret = 0, total = 0, remain = PAGE_SIZE;
+        struct ocfs2_stack_plugin *p;
+
+        spin_lock(&ocfs2_stack_lock);
+        list_for_each_entry(p, &ocfs2_stack_list, sp_list) {
+                ret = snprintf(buf, remain, "%s\n",
+                               p->sp_name);
+                if (ret < 0) {
+                        total = ret;
+                        break;
+                }
+                if (ret == remain) {
+                        /* snprintf() didn't fit */
+                        total = -E2BIG;
+                        break;
+                }
+                total += ret;
+                remain -= ret;
+        }
+        spin_unlock(&ocfs2_stack_lock);
+
+        return total;
+}
+
+static struct kobj_attribute ocfs2_attr_loaded_cluster_plugins =
+        __ATTR(loaded_cluster_plugins, S_IFREG | S_IRUGO,
+               ocfs2_loaded_cluster_plugins_show, NULL);
+
+static ssize_t ocfs2_active_cluster_plugin_show(struct kobject *kobj,
+                                                struct kobj_attribute *attr,
+                                                char *buf)
+{
+        ssize_t ret = 0;
+
+        spin_lock(&ocfs2_stack_lock);
+        if (active_stack) {
+                ret = snprintf(buf, PAGE_SIZE, "%s\n",
+                               active_stack->sp_name);
+                if (ret == PAGE_SIZE)
+                        ret = -E2BIG;
+        }
+        spin_unlock(&ocfs2_stack_lock);
+
+        return ret;
+}
+
+static struct kobj_attribute ocfs2_attr_active_cluster_plugin =
+        __ATTR(active_cluster_plugin, S_IFREG | S_IRUGO,
+               ocfs2_active_cluster_plugin_show, NULL);
+
+static ssize_t ocfs2_cluster_stack_show(struct kobject *kobj,
+                                        struct kobj_attribute *attr,
+                                        char *buf)
+{
+        ssize_t ret;
+        spin_lock(&ocfs2_stack_lock);
+        ret = snprintf(buf, PAGE_SIZE, "%s\n", cluster_stack_name);
+        spin_unlock(&ocfs2_stack_lock);
+
+        return ret;
+}
+
+static ssize_t ocfs2_cluster_stack_store(struct kobject *kobj,
+                                         struct kobj_attribute *attr,
+                                         const char *buf, size_t count)
+{
+        size_t len = count;
+        ssize_t ret;
+
+        if (len == 0)
+                return len;
+
+        if (buf[len - 1] == '\n')
+                len--;
+
+        if ((len != OCFS2_STACK_LABEL_LEN) ||
+            (strnlen(buf, len) != len))
+                return -EINVAL;
+
+        spin_lock(&ocfs2_stack_lock);
+        if (active_stack) {
+                if (!strncmp(buf, cluster_stack_name, len))
+                        ret = count;
+                else
+                        ret = -EBUSY;
+        } else {
+                memcpy(cluster_stack_name, buf, len);
+                ret = count;
+        }
+        spin_unlock(&ocfs2_stack_lock);
+
+        return ret;
+}
+
+
+static struct kobj_attribute ocfs2_attr_cluster_stack =
+        __ATTR(cluster_stack, S_IFREG | S_IRUGO | S_IWUSR,
+               ocfs2_cluster_stack_show,
+               ocfs2_cluster_stack_store);
+
+static struct attribute *ocfs2_attrs[] = {
+        &ocfs2_attr_max_locking_protocol.attr,
+        &ocfs2_attr_loaded_cluster_plugins.attr,
+        &ocfs2_attr_active_cluster_plugin.attr,
+        &ocfs2_attr_cluster_stack.attr,
+        NULL,
+};
+
+static struct attribute_group ocfs2_attr_group = {
+        .attrs = ocfs2_attrs,
+};
+
+static struct kset *ocfs2_kset;
+
+static void ocfs2_sysfs_exit(void)
+{
+        kset_unregister(ocfs2_kset);
+}
+
+static int ocfs2_sysfs_init(void)
+{
+        int ret;
+
+        ocfs2_kset = kset_create_and_add("ocfs2", NULL, fs_kobj);
+        if (!ocfs2_kset)
+                return -ENOMEM;
+
+        ret = sysfs_create_group(&ocfs2_kset->kobj, &ocfs2_attr_group);
+        if (ret)
+                goto error;
+
+        return 0;
+
+error:
+        kset_unregister(ocfs2_kset);
+        return ret;
+}
+
+static int __init ocfs2_stack_glue_init(void)
+{
+        strcpy(cluster_stack_name, OCFS2_STACK_PLUGIN_O2CB);
+
+        return ocfs2_sysfs_init();
+}
+
+static void __exit ocfs2_stack_glue_exit(void)
+{
+        lproto = NULL;
+        ocfs2_sysfs_exit();
+}
+
+MODULE_AUTHOR("Oracle");
+MODULE_DESCRIPTION("ocfs2 cluter stack glue layer");
+MODULE_LICENSE("GPL");
+module_init(ocfs2_stack_glue_init);
+module_exit(ocfs2_stack_glue_exit);