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linux-sg2042/fs/ocfs2/stackglue.c

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/* -*- 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, 2009 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 <linux/sysctl.h>
#include "ocfs2_fs.h"
#include "stackglue.h"
#define OCFS2_STACK_PLUGIN_O2CB "o2cb"
#define OCFS2_STACK_PLUGIN_USER "user"
#define OCFS2_MAX_HB_CTL_PATH 256
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];
static char ocfs2_hb_ctl_path[OCFS2_MAX_HB_CTL_PATH] = "/sbin/ocfs2_hb_ctl";
/*
* 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;
}
active_stack = p;
rc = 0;
out:
/* If we found it, pin it */
if (!rc)
active_stack->sp_count++;
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_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);
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_max_proto_version(struct ocfs2_protocol_version *max_proto)
{
struct ocfs2_stack_plugin *p;
spin_lock(&ocfs2_stack_lock);
if (memcmp(max_proto, &locking_max_version,
sizeof(struct ocfs2_protocol_version))) {
BUG_ON(locking_max_version.pv_major != 0);
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_max_proto_version);
/*
* The ocfs2_dlm_lock() and ocfs2_dlm_unlock() functions take no argument
* for the ast and bast functions. They will pass the lksb to the ast
* and bast. The caller can wrap the lksb with their own structure to
* get more information.
*/
int ocfs2_dlm_lock(struct ocfs2_cluster_connection *conn,
int mode,
struct ocfs2_dlm_lksb *lksb,
u32 flags,
void *name,
unsigned int namelen)
{
if (!lksb->lksb_conn)
lksb->lksb_conn = conn;
else
BUG_ON(lksb->lksb_conn != conn);
return active_stack->sp_ops->dlm_lock(conn, mode, lksb, flags,
name, namelen);
}
EXPORT_SYMBOL_GPL(ocfs2_dlm_lock);
int ocfs2_dlm_unlock(struct ocfs2_cluster_connection *conn,
struct ocfs2_dlm_lksb *lksb,
u32 flags)
{
BUG_ON(lksb->lksb_conn == NULL);
return active_stack->sp_ops->dlm_unlock(conn, lksb, flags);
}
EXPORT_SYMBOL_GPL(ocfs2_dlm_unlock);
int ocfs2_dlm_lock_status(struct ocfs2_dlm_lksb *lksb)
{
return active_stack->sp_ops->lock_status(lksb);
}
EXPORT_SYMBOL_GPL(ocfs2_dlm_lock_status);
int ocfs2_dlm_lvb_valid(struct ocfs2_dlm_lksb *lksb)
{
return active_stack->sp_ops->lvb_valid(lksb);
}
EXPORT_SYMBOL_GPL(ocfs2_dlm_lvb_valid);
void *ocfs2_dlm_lvb(struct ocfs2_dlm_lksb *lksb)
{
return active_stack->sp_ops->lock_lvb(lksb);
}
EXPORT_SYMBOL_GPL(ocfs2_dlm_lvb);
void ocfs2_dlm_dump_lksb(struct ocfs2_dlm_lksb *lksb)
{
active_stack->sp_ops->dump_lksb(lksb);
}
EXPORT_SYMBOL_GPL(ocfs2_dlm_dump_lksb);
int ocfs2_stack_supports_plocks(void)
{
return active_stack && active_stack->sp_ops->plock;
}
EXPORT_SYMBOL_GPL(ocfs2_stack_supports_plocks);
/*
* ocfs2_plock() can only be safely called if
* ocfs2_stack_supports_plocks() returned true
*/
int ocfs2_plock(struct ocfs2_cluster_connection *conn, u64 ino,
struct file *file, int cmd, struct file_lock *fl)
{
WARN_ON_ONCE(active_stack->sp_ops->plock == NULL);
if (active_stack->sp_ops->plock)
return active_stack->sp_ops->plock(conn, ino, file, cmd, fl);
return -EOPNOTSUPP;
}
EXPORT_SYMBOL_GPL(ocfs2_plock);
int ocfs2_cluster_connect(const char *stack_name,
const char *cluster_name,
int cluster_name_len,
const char *group,
int grouplen,
struct ocfs2_locking_protocol *lproto,
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;
}
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) {
rc = -ENOMEM;
goto out;
}
strlcpy(new_conn->cc_name, group, GROUP_NAME_MAX + 1);
new_conn->cc_namelen = grouplen;
if (cluster_name_len)
strlcpy(new_conn->cc_cluster_name, cluster_name,
CLUSTER_NAME_MAX + 1);
new_conn->cc_cluster_name_len = cluster_name_len;
new_conn->cc_recovery_handler = recovery_handler;
new_conn->cc_recovery_data = recovery_data;
new_conn->cc_proto = lproto;
/* 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);
/* The caller will ensure all nodes have the same cluster stack */
int ocfs2_cluster_connect_agnostic(const char *group,
int grouplen,
struct ocfs2_locking_protocol *lproto,
void (*recovery_handler)(int node_num,
void *recovery_data),
void *recovery_data,
struct ocfs2_cluster_connection **conn)
{
char *stack_name = NULL;
if (cluster_stack_name[0])
stack_name = cluster_stack_name;
return ocfs2_cluster_connect(stack_name, NULL, 0, group, grouplen,
lproto, recovery_handler, recovery_data,
conn);
}
EXPORT_SYMBOL_GPL(ocfs2_cluster_connect_agnostic);
/* 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);
/* 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);
/*
* Leave the group for this filesystem. This is executed by a userspace
* program (stored in ocfs2_hb_ctl_path).
*/
static void ocfs2_leave_group(const char *group)
{
int ret;
char *argv[5], *envp[3];
argv[0] = ocfs2_hb_ctl_path;
argv[1] = "-K";
argv[2] = "-u";
argv[3] = (char *)group;
argv[4] = NULL;
/* minimal command environment taken from cpu_run_sbin_hotplug */
envp[0] = "HOME=/";
envp[1] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
envp[2] = NULL;
ret = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_PROC);
if (ret < 0) {
printk(KERN_ERR
"ocfs2: Error %d running user helper "
"\"%s %s %s %s\"\n",
ret, argv[0], argv[1], argv[2], argv[3]);
}
}
/*
* Hangup is a required post-umount. ocfs2-tools software expects the
* filesystem to call "ocfs2_hb_ctl" during unmount. This happens
* regardless of whether the DLM got started, so we can't do it
* in ocfs2_cluster_disconnect(). The ocfs2_leave_group() function does
* the actual work.
*/
void ocfs2_cluster_hangup(const char *group, int grouplen)
{
BUG_ON(group == NULL);
BUG_ON(group[grouplen] != '\0');
ocfs2_leave_group(group);
/* cluster_disconnect() was called with hangup_pending==1 */
ocfs2_stack_driver_put();
}
EXPORT_SYMBOL_GPL(ocfs2_cluster_hangup);
int ocfs2_cluster_this_node(struct ocfs2_cluster_connection *conn,
unsigned int *node)
{
return active_stack->sp_ops->this_node(conn, 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 (locking_max_version.pv_major)
ret = snprintf(buf, PAGE_SIZE, "%u.%u\n",
locking_max_version.pv_major,
locking_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_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_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_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_IRUGO | S_IWUSR,
ocfs2_cluster_stack_show,
ocfs2_cluster_stack_store);
static ssize_t ocfs2_dlm_recover_show(struct kobject *kobj,
struct kobj_attribute *attr,
char *buf)
{
return snprintf(buf, PAGE_SIZE, "1\n");
}
static struct kobj_attribute ocfs2_attr_dlm_recover_support =
__ATTR(dlm_recover_callback_support, S_IRUGO,
ocfs2_dlm_recover_show, NULL);
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,
&ocfs2_attr_dlm_recover_support.attr,
NULL,
};
static struct attribute_group ocfs2_attr_group = {
.attrs = ocfs2_attrs,
};
struct kset *ocfs2_kset;
EXPORT_SYMBOL_GPL(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;
}
/*
* Sysctl bits
*
* The sysctl lives at /proc/sys/fs/ocfs2/nm/hb_ctl_path. The 'nm' doesn't
* make as much sense in a multiple cluster stack world, but it's safer
* and easier to preserve the name.
*/
#define FS_OCFS2_NM 1
static struct ctl_table ocfs2_nm_table[] = {
{
.procname = "hb_ctl_path",
.data = ocfs2_hb_ctl_path,
.maxlen = OCFS2_MAX_HB_CTL_PATH,
.mode = 0644,
.proc_handler = proc_dostring,
},
{ }
};
static struct ctl_table ocfs2_mod_table[] = {
{
.procname = "nm",
.data = NULL,
.maxlen = 0,
.mode = 0555,
.child = ocfs2_nm_table
},
{ }
};
static struct ctl_table ocfs2_kern_table[] = {
{
.procname = "ocfs2",
.data = NULL,
.maxlen = 0,
.mode = 0555,
.child = ocfs2_mod_table
},
{ }
};
static struct ctl_table ocfs2_root_table[] = {
{
.procname = "fs",
.data = NULL,
.maxlen = 0,
.mode = 0555,
.child = ocfs2_kern_table
},
{ }
};
static struct ctl_table_header *ocfs2_table_header;
/*
* Initialization
*/
static int __init ocfs2_stack_glue_init(void)
{
strcpy(cluster_stack_name, OCFS2_STACK_PLUGIN_O2CB);
ocfs2_table_header = register_sysctl_table(ocfs2_root_table);
if (!ocfs2_table_header) {
printk(KERN_ERR
"ocfs2 stack glue: unable to register sysctl\n");
return -ENOMEM; /* or something. */
}
return ocfs2_sysfs_init();
}
static void __exit ocfs2_stack_glue_exit(void)
{
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);
}
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);
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