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/* -*- mode: c; c-basic-offset: 8; -*-
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* vim: noexpandtab sw=8 ts=8 sts=0:
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* Code which implements an OCFS2 specific interface to underlying
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* Copyright (C) 2007, 2009 Oracle. All rights reserved.
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public
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* License as published by the Free Software Foundation, version 2.
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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#include <linux/list.h>
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#include <linux/spinlock.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/kmod.h>
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#include <linux/kobject.h>
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#include <linux/sysfs.h>
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#include <linux/sysctl.h>
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#include "stackglue.h"
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#define OCFS2_STACK_PLUGIN_O2CB "o2cb"
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#define OCFS2_STACK_PLUGIN_USER "user"
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#define OCFS2_MAX_HB_CTL_PATH 256
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static struct ocfs2_protocol_version locking_max_version;
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static DEFINE_SPINLOCK(ocfs2_stack_lock);
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static LIST_HEAD(ocfs2_stack_list);
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static char cluster_stack_name[OCFS2_STACK_LABEL_LEN + 1];
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static char ocfs2_hb_ctl_path[OCFS2_MAX_HB_CTL_PATH] = "/sbin/ocfs2_hb_ctl";
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* The stack currently in use. If not null, active_stack->sp_count > 0,
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* the module is pinned, and the locking protocol cannot be changed.
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static struct ocfs2_stack_plugin *active_stack;
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static struct ocfs2_stack_plugin *ocfs2_stack_lookup(const char *name)
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struct ocfs2_stack_plugin *p;
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assert_spin_locked(&ocfs2_stack_lock);
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list_for_each_entry(p, &ocfs2_stack_list, sp_list) {
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if (!strcmp(p->sp_name, name))
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static int ocfs2_stack_driver_request(const char *stack_name,
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const char *plugin_name)
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struct ocfs2_stack_plugin *p;
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spin_lock(&ocfs2_stack_lock);
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* If the stack passed by the filesystem isn't the selected one,
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if (strcmp(stack_name, cluster_stack_name)) {
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* If the active stack isn't the one we want, it cannot
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* be selected right now.
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if (!strcmp(active_stack->sp_name, plugin_name))
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p = ocfs2_stack_lookup(plugin_name);
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if (!p || !try_module_get(p->sp_owner)) {
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/* If we found it, pin it */
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active_stack->sp_count++;
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spin_unlock(&ocfs2_stack_lock);
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* This function looks up the appropriate stack and makes it active. If
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* there is no stack, it tries to load it. It will fail if the stack still
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* cannot be found. It will also fail if a different stack is in use.
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static int ocfs2_stack_driver_get(const char *stack_name)
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char *plugin_name = OCFS2_STACK_PLUGIN_O2CB;
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* Classic stack does not pass in a stack name. This is
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* compatible with older tools as well.
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if (!stack_name || !*stack_name)
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stack_name = OCFS2_STACK_PLUGIN_O2CB;
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if (strlen(stack_name) != OCFS2_STACK_LABEL_LEN) {
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"ocfs2 passed an invalid cluster stack label: \"%s\"\n",
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/* Anything that isn't the classic stack is a user stack */
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if (strcmp(stack_name, OCFS2_STACK_PLUGIN_O2CB))
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plugin_name = OCFS2_STACK_PLUGIN_USER;
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rc = ocfs2_stack_driver_request(stack_name, plugin_name);
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request_module("ocfs2_stack_%s", plugin_name);
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rc = ocfs2_stack_driver_request(stack_name, plugin_name);
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"ocfs2: Cluster stack driver \"%s\" cannot be found\n",
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} else if (rc == -EBUSY) {
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"ocfs2: A different cluster stack is in use\n");
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static void ocfs2_stack_driver_put(void)
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spin_lock(&ocfs2_stack_lock);
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BUG_ON(active_stack == NULL);
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BUG_ON(active_stack->sp_count == 0);
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active_stack->sp_count--;
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if (!active_stack->sp_count) {
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module_put(active_stack->sp_owner);
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spin_unlock(&ocfs2_stack_lock);
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int ocfs2_stack_glue_register(struct ocfs2_stack_plugin *plugin)
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spin_lock(&ocfs2_stack_lock);
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if (!ocfs2_stack_lookup(plugin->sp_name)) {
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plugin->sp_count = 0;
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plugin->sp_max_proto = locking_max_version;
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list_add(&plugin->sp_list, &ocfs2_stack_list);
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printk(KERN_INFO "ocfs2: Registered cluster interface %s\n",
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printk(KERN_ERR "ocfs2: Stack \"%s\" already registered\n",
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spin_unlock(&ocfs2_stack_lock);
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EXPORT_SYMBOL_GPL(ocfs2_stack_glue_register);
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void ocfs2_stack_glue_unregister(struct ocfs2_stack_plugin *plugin)
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struct ocfs2_stack_plugin *p;
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spin_lock(&ocfs2_stack_lock);
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p = ocfs2_stack_lookup(plugin->sp_name);
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BUG_ON(plugin == active_stack);
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BUG_ON(plugin->sp_count != 0);
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list_del_init(&plugin->sp_list);
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printk(KERN_INFO "ocfs2: Unregistered cluster interface %s\n",
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printk(KERN_ERR "Stack \"%s\" is not registered\n",
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spin_unlock(&ocfs2_stack_lock);
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EXPORT_SYMBOL_GPL(ocfs2_stack_glue_unregister);
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void ocfs2_stack_glue_set_max_proto_version(struct ocfs2_protocol_version *max_proto)
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struct ocfs2_stack_plugin *p;
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spin_lock(&ocfs2_stack_lock);
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if (memcmp(max_proto, &locking_max_version,
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sizeof(struct ocfs2_protocol_version))) {
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BUG_ON(locking_max_version.pv_major != 0);
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locking_max_version = *max_proto;
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list_for_each_entry(p, &ocfs2_stack_list, sp_list) {
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p->sp_max_proto = locking_max_version;
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spin_unlock(&ocfs2_stack_lock);
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EXPORT_SYMBOL_GPL(ocfs2_stack_glue_set_max_proto_version);
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* The ocfs2_dlm_lock() and ocfs2_dlm_unlock() functions take no argument
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* for the ast and bast functions. They will pass the lksb to the ast
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* and bast. The caller can wrap the lksb with their own structure to
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* get more information.
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int ocfs2_dlm_lock(struct ocfs2_cluster_connection *conn,
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struct ocfs2_dlm_lksb *lksb,
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unsigned int namelen)
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if (!lksb->lksb_conn)
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lksb->lksb_conn = conn;
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BUG_ON(lksb->lksb_conn != conn);
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return active_stack->sp_ops->dlm_lock(conn, mode, lksb, flags,
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EXPORT_SYMBOL_GPL(ocfs2_dlm_lock);
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int ocfs2_dlm_unlock(struct ocfs2_cluster_connection *conn,
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struct ocfs2_dlm_lksb *lksb,
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BUG_ON(lksb->lksb_conn == NULL);
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return active_stack->sp_ops->dlm_unlock(conn, lksb, flags);
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EXPORT_SYMBOL_GPL(ocfs2_dlm_unlock);
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int ocfs2_dlm_lock_status(struct ocfs2_dlm_lksb *lksb)
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return active_stack->sp_ops->lock_status(lksb);
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EXPORT_SYMBOL_GPL(ocfs2_dlm_lock_status);
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int ocfs2_dlm_lvb_valid(struct ocfs2_dlm_lksb *lksb)
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return active_stack->sp_ops->lvb_valid(lksb);
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EXPORT_SYMBOL_GPL(ocfs2_dlm_lvb_valid);
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void *ocfs2_dlm_lvb(struct ocfs2_dlm_lksb *lksb)
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return active_stack->sp_ops->lock_lvb(lksb);
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EXPORT_SYMBOL_GPL(ocfs2_dlm_lvb);
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void ocfs2_dlm_dump_lksb(struct ocfs2_dlm_lksb *lksb)
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active_stack->sp_ops->dump_lksb(lksb);
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EXPORT_SYMBOL_GPL(ocfs2_dlm_dump_lksb);
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int ocfs2_stack_supports_plocks(void)
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return active_stack && active_stack->sp_ops->plock;
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EXPORT_SYMBOL_GPL(ocfs2_stack_supports_plocks);
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* ocfs2_plock() can only be safely called if
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* ocfs2_stack_supports_plocks() returned true
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int ocfs2_plock(struct ocfs2_cluster_connection *conn, u64 ino,
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struct file *file, int cmd, struct file_lock *fl)
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WARN_ON_ONCE(active_stack->sp_ops->plock == NULL);
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if (active_stack->sp_ops->plock)
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return active_stack->sp_ops->plock(conn, ino, file, cmd, fl);
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EXPORT_SYMBOL_GPL(ocfs2_plock);
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int ocfs2_cluster_connect(const char *stack_name,
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struct ocfs2_locking_protocol *lproto,
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void (*recovery_handler)(int node_num,
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void *recovery_data),
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struct ocfs2_cluster_connection **conn)
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struct ocfs2_cluster_connection *new_conn;
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BUG_ON(group == NULL);
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BUG_ON(conn == NULL);
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BUG_ON(recovery_handler == NULL);
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if (grouplen > GROUP_NAME_MAX) {
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if (memcmp(&lproto->lp_max_version, &locking_max_version,
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sizeof(struct ocfs2_protocol_version))) {
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new_conn = kzalloc(sizeof(struct ocfs2_cluster_connection),
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memcpy(new_conn->cc_name, group, grouplen);
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new_conn->cc_namelen = grouplen;
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new_conn->cc_recovery_handler = recovery_handler;
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new_conn->cc_recovery_data = recovery_data;
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new_conn->cc_proto = lproto;
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/* Start the new connection at our maximum compatibility level */
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new_conn->cc_version = lproto->lp_max_version;
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/* This will pin the stack driver if successful */
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rc = ocfs2_stack_driver_get(stack_name);
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rc = active_stack->sp_ops->connect(new_conn);
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ocfs2_stack_driver_put();
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EXPORT_SYMBOL_GPL(ocfs2_cluster_connect);
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/* The caller will ensure all nodes have the same cluster stack */
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int ocfs2_cluster_connect_agnostic(const char *group,
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struct ocfs2_locking_protocol *lproto,
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void (*recovery_handler)(int node_num,
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void *recovery_data),
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struct ocfs2_cluster_connection **conn)
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char *stack_name = NULL;
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if (cluster_stack_name[0])
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stack_name = cluster_stack_name;
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return ocfs2_cluster_connect(stack_name, group, grouplen, lproto,
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recovery_handler, recovery_data, conn);
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EXPORT_SYMBOL_GPL(ocfs2_cluster_connect_agnostic);
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/* If hangup_pending is 0, the stack driver will be dropped */
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int ocfs2_cluster_disconnect(struct ocfs2_cluster_connection *conn,
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BUG_ON(conn == NULL);
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ret = active_stack->sp_ops->disconnect(conn);
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/* XXX Should we free it anyway? */
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ocfs2_stack_driver_put();
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EXPORT_SYMBOL_GPL(ocfs2_cluster_disconnect);
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* Leave the group for this filesystem. This is executed by a userspace
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* program (stored in ocfs2_hb_ctl_path).
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static void ocfs2_leave_group(const char *group)
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char *argv[5], *envp[3];
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argv[0] = ocfs2_hb_ctl_path;
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argv[3] = (char *)group;
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/* minimal command environment taken from cpu_run_sbin_hotplug */
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envp[1] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
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ret = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_PROC);
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"ocfs2: Error %d running user helper "
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ret, argv[0], argv[1], argv[2], argv[3]);
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* Hangup is a required post-umount. ocfs2-tools software expects the
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* filesystem to call "ocfs2_hb_ctl" during unmount. This happens
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* regardless of whether the DLM got started, so we can't do it
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* in ocfs2_cluster_disconnect(). The ocfs2_leave_group() function does
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void ocfs2_cluster_hangup(const char *group, int grouplen)
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BUG_ON(group == NULL);
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BUG_ON(group[grouplen] != '\0');
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ocfs2_leave_group(group);
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/* cluster_disconnect() was called with hangup_pending==1 */
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ocfs2_stack_driver_put();
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EXPORT_SYMBOL_GPL(ocfs2_cluster_hangup);
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int ocfs2_cluster_this_node(unsigned int *node)
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return active_stack->sp_ops->this_node(node);
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EXPORT_SYMBOL_GPL(ocfs2_cluster_this_node);
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static ssize_t ocfs2_max_locking_protocol_show(struct kobject *kobj,
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struct kobj_attribute *attr,
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spin_lock(&ocfs2_stack_lock);
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if (locking_max_version.pv_major)
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ret = snprintf(buf, PAGE_SIZE, "%u.%u\n",
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locking_max_version.pv_major,
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locking_max_version.pv_minor);
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spin_unlock(&ocfs2_stack_lock);
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static struct kobj_attribute ocfs2_attr_max_locking_protocol =
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__ATTR(max_locking_protocol, S_IFREG | S_IRUGO,
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ocfs2_max_locking_protocol_show, NULL);
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static ssize_t ocfs2_loaded_cluster_plugins_show(struct kobject *kobj,
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struct kobj_attribute *attr,
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ssize_t ret = 0, total = 0, remain = PAGE_SIZE;
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struct ocfs2_stack_plugin *p;
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spin_lock(&ocfs2_stack_lock);
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list_for_each_entry(p, &ocfs2_stack_list, sp_list) {
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ret = snprintf(buf, remain, "%s\n",
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/* snprintf() didn't fit */
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spin_unlock(&ocfs2_stack_lock);
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static struct kobj_attribute ocfs2_attr_loaded_cluster_plugins =
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__ATTR(loaded_cluster_plugins, S_IFREG | S_IRUGO,
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ocfs2_loaded_cluster_plugins_show, NULL);
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static ssize_t ocfs2_active_cluster_plugin_show(struct kobject *kobj,
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struct kobj_attribute *attr,
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spin_lock(&ocfs2_stack_lock);
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ret = snprintf(buf, PAGE_SIZE, "%s\n",
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active_stack->sp_name);
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if (ret == PAGE_SIZE)
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spin_unlock(&ocfs2_stack_lock);
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static struct kobj_attribute ocfs2_attr_active_cluster_plugin =
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__ATTR(active_cluster_plugin, S_IFREG | S_IRUGO,
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ocfs2_active_cluster_plugin_show, NULL);
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static ssize_t ocfs2_cluster_stack_show(struct kobject *kobj,
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struct kobj_attribute *attr,
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spin_lock(&ocfs2_stack_lock);
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ret = snprintf(buf, PAGE_SIZE, "%s\n", cluster_stack_name);
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spin_unlock(&ocfs2_stack_lock);
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static ssize_t ocfs2_cluster_stack_store(struct kobject *kobj,
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struct kobj_attribute *attr,
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const char *buf, size_t count)
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if (buf[len - 1] == '\n')
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if ((len != OCFS2_STACK_LABEL_LEN) ||
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(strnlen(buf, len) != len))
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spin_lock(&ocfs2_stack_lock);
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if (!strncmp(buf, cluster_stack_name, len))
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memcpy(cluster_stack_name, buf, len);
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spin_unlock(&ocfs2_stack_lock);
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static struct kobj_attribute ocfs2_attr_cluster_stack =
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__ATTR(cluster_stack, S_IFREG | S_IRUGO | S_IWUSR,
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ocfs2_cluster_stack_show,
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ocfs2_cluster_stack_store);
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static struct attribute *ocfs2_attrs[] = {
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&ocfs2_attr_max_locking_protocol.attr,
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&ocfs2_attr_loaded_cluster_plugins.attr,
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&ocfs2_attr_active_cluster_plugin.attr,
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&ocfs2_attr_cluster_stack.attr,
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static struct attribute_group ocfs2_attr_group = {
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.attrs = ocfs2_attrs,
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static struct kset *ocfs2_kset;
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static void ocfs2_sysfs_exit(void)
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kset_unregister(ocfs2_kset);
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static int ocfs2_sysfs_init(void)
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ocfs2_kset = kset_create_and_add("ocfs2", NULL, fs_kobj);
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ret = sysfs_create_group(&ocfs2_kset->kobj, &ocfs2_attr_group);
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kset_unregister(ocfs2_kset);
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* The sysctl lives at /proc/sys/fs/ocfs2/nm/hb_ctl_path. The 'nm' doesn't
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* make as much sense in a multiple cluster stack world, but it's safer
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* and easier to preserve the name.
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#define FS_OCFS2_NM 1
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static ctl_table ocfs2_nm_table[] = {
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.procname = "hb_ctl_path",
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.data = ocfs2_hb_ctl_path,
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.maxlen = OCFS2_MAX_HB_CTL_PATH,
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.proc_handler = proc_dostring,
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static ctl_table ocfs2_mod_table[] = {
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.child = ocfs2_nm_table
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static ctl_table ocfs2_kern_table[] = {
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.child = ocfs2_mod_table
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static ctl_table ocfs2_root_table[] = {
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.child = ocfs2_kern_table
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static struct ctl_table_header *ocfs2_table_header = NULL;
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static int __init ocfs2_stack_glue_init(void)
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strcpy(cluster_stack_name, OCFS2_STACK_PLUGIN_O2CB);
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ocfs2_table_header = register_sysctl_table(ocfs2_root_table);
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if (!ocfs2_table_header) {
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"ocfs2 stack glue: unable to register sysctl\n");
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return -ENOMEM; /* or something. */
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return ocfs2_sysfs_init();
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static void __exit ocfs2_stack_glue_exit(void)
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memset(&locking_max_version, 0,
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sizeof(struct ocfs2_protocol_version));
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locking_max_version.pv_major = 0;
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locking_max_version.pv_minor = 0;
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if (ocfs2_table_header)
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unregister_sysctl_table(ocfs2_table_header);
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MODULE_AUTHOR("Oracle");
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MODULE_DESCRIPTION("ocfs2 cluter stack glue layer");
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MODULE_LICENSE("GPL");
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module_init(ocfs2_stack_glue_init);
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module_exit(ocfs2_stack_glue_exit);