diff options
Diffstat (limited to 'fs/ocfs2/stackglue.c')
| -rw-r--r-- | fs/ocfs2/stackglue.c | 568 |
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); |