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-rw-r--r--fs/ocfs2/stackglue.c568
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);
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.