123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365366367368369370371372373374375376377378379380381382383384385386387388389390391392393394395396397398399400401402403404405406407408409410411412413414415416417418419420421422423424425426427428429430431432433434435436437438439440441442443444445446447448449450451452453454455456457458459460461462463464465466467468469470471472473474475476477478479480481482483484485486487488489490491492493494495496497498499500501502503504505506507508509510511512513514515516517518519520521522523524525526527528529530531532533534535536537538539540541542543544545546547548549550551552553554555556557558559560561562 |
- /* -*- mode: c; c-basic-offset: 8; -*-
- * vim: noexpandtab sw=8 ts=8 sts=0:
- *
- * stack_user.c
- *
- * Code which interfaces ocfs2 with fs/dlm and a userspace stack.
- *
- * 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/module.h>
- #include <linux/fs.h>
- #include <linux/miscdevice.h>
- #include <linux/mutex.h>
- #include <linux/reboot.h>
- #include <asm/uaccess.h>
- #include "stackglue.h"
- /*
- * The control protocol starts with a handshake. Until the handshake
- * is complete, the control device will fail all write(2)s.
- *
- * The handshake is simple. First, the client reads until EOF. Each line
- * of output is a supported protocol tag. All protocol tags are a single
- * character followed by a two hex digit version number. Currently the
- * only things supported is T01, for "Text-base version 0x01". Next, the
- * client writes the version they would like to use, including the newline.
- * Thus, the protocol tag is 'T01\n'. If the version tag written is
- * unknown, -EINVAL is returned. Once the negotiation is complete, the
- * client can start sending messages.
- *
- * The T01 protocol only has two messages. First is the "SETN" message.
- * It has the following syntax:
- *
- * SETN<space><8-char-hex-nodenum><newline>
- *
- * This is 14 characters.
- *
- * The "SETN" message must be the first message following the protocol.
- * It tells ocfs2_control the local node number.
- *
- * Once the local node number has been set, the "DOWN" message can be
- * sent for node down notification. It has the following syntax:
- *
- * DOWN<space><32-char-cap-hex-uuid><space><8-char-hex-nodenum><newline>
- *
- * eg:
- *
- * DOWN 632A924FDD844190BDA93C0DF6B94899 00000001\n
- *
- * This is 47 characters.
- */
- /*
- * Whether or not the client has done the handshake.
- * For now, we have just one protocol version.
- */
- #define OCFS2_CONTROL_PROTO "T01\n"
- #define OCFS2_CONTROL_PROTO_LEN 4
- /* Handshake states */
- #define OCFS2_CONTROL_HANDSHAKE_INVALID (0)
- #define OCFS2_CONTROL_HANDSHAKE_READ (1)
- #define OCFS2_CONTROL_HANDSHAKE_PROTOCOL (2)
- #define OCFS2_CONTROL_HANDSHAKE_VALID (3)
- /* Messages */
- #define OCFS2_CONTROL_MESSAGE_OP_LEN 4
- #define OCFS2_CONTROL_MESSAGE_SETNODE_OP "SETN"
- #define OCFS2_CONTROL_MESSAGE_SETNODE_TOTAL_LEN 14
- #define OCFS2_CONTROL_MESSAGE_DOWN_OP "DOWN"
- #define OCFS2_CONTROL_MESSAGE_DOWN_TOTAL_LEN 47
- #define OCFS2_TEXT_UUID_LEN 32
- #define OCFS2_CONTROL_MESSAGE_NODENUM_LEN 8
- /*
- * ocfs2_live_connection is refcounted because the filesystem and
- * miscdevice sides can detach in different order. Let's just be safe.
- */
- struct ocfs2_live_connection {
- struct list_head oc_list;
- struct ocfs2_cluster_connection *oc_conn;
- };
- struct ocfs2_control_private {
- struct list_head op_list;
- int op_state;
- int op_this_node;
- };
- /* SETN<space><8-char-hex-nodenum><newline> */
- struct ocfs2_control_message_setn {
- char tag[OCFS2_CONTROL_MESSAGE_OP_LEN];
- char space;
- char nodestr[OCFS2_CONTROL_MESSAGE_NODENUM_LEN];
- char newline;
- };
- /* DOWN<space><32-char-cap-hex-uuid><space><8-char-hex-nodenum><newline> */
- struct ocfs2_control_message_down {
- char tag[OCFS2_CONTROL_MESSAGE_OP_LEN];
- char space1;
- char uuid[OCFS2_TEXT_UUID_LEN];
- char space2;
- char nodestr[OCFS2_CONTROL_MESSAGE_NODENUM_LEN];
- char newline;
- };
- union ocfs2_control_message {
- char tag[OCFS2_CONTROL_MESSAGE_OP_LEN];
- struct ocfs2_control_message_setn u_setn;
- struct ocfs2_control_message_down u_down;
- };
- static atomic_t ocfs2_control_opened;
- static int ocfs2_control_this_node = -1;
- static LIST_HEAD(ocfs2_live_connection_list);
- static LIST_HEAD(ocfs2_control_private_list);
- static DEFINE_MUTEX(ocfs2_control_lock);
- static inline void ocfs2_control_set_handshake_state(struct file *file,
- int state)
- {
- struct ocfs2_control_private *p = file->private_data;
- p->op_state = state;
- }
- static inline int ocfs2_control_get_handshake_state(struct file *file)
- {
- struct ocfs2_control_private *p = file->private_data;
- return p->op_state;
- }
- static struct ocfs2_live_connection *ocfs2_connection_find(const char *name)
- {
- size_t len = strlen(name);
- struct ocfs2_live_connection *c;
- BUG_ON(!mutex_is_locked(&ocfs2_control_lock));
- list_for_each_entry(c, &ocfs2_live_connection_list, oc_list) {
- if ((c->oc_conn->cc_namelen == len) &&
- !strncmp(c->oc_conn->cc_name, name, len))
- return c;
- }
- return c;
- }
- /*
- * ocfs2_live_connection structures are created underneath the ocfs2
- * mount path. Since the VFS prevents multiple calls to
- * fill_super(), we can't get dupes here.
- */
- static int ocfs2_live_connection_new(struct ocfs2_cluster_connection *conn,
- struct ocfs2_live_connection **c_ret)
- {
- int rc = 0;
- struct ocfs2_live_connection *c;
- c = kzalloc(sizeof(struct ocfs2_live_connection), GFP_KERNEL);
- if (!c)
- return -ENOMEM;
- mutex_lock(&ocfs2_control_lock);
- c->oc_conn = conn;
- if (atomic_read(&ocfs2_control_opened))
- list_add(&c->oc_list, &ocfs2_live_connection_list);
- else {
- printk(KERN_ERR
- "ocfs2: Userspace control daemon is not present\n");
- rc = -ESRCH;
- }
- mutex_unlock(&ocfs2_control_lock);
- if (!rc)
- *c_ret = c;
- else
- kfree(c);
- return rc;
- }
- /*
- * This function disconnects the cluster connection from ocfs2_control.
- * Afterwards, userspace can't affect the cluster connection.
- */
- static void ocfs2_live_connection_drop(struct ocfs2_live_connection *c)
- {
- mutex_lock(&ocfs2_control_lock);
- list_del_init(&c->oc_list);
- c->oc_conn = NULL;
- mutex_unlock(&ocfs2_control_lock);
- kfree(c);
- }
- static int ocfs2_control_cfu(void *target, size_t target_len,
- const char __user *buf, size_t count)
- {
- /* The T01 expects write(2) calls to have exactly one command */
- if ((count != target_len) ||
- (count > sizeof(union ocfs2_control_message)))
- return -EINVAL;
- if (copy_from_user(target, buf, target_len))
- return -EFAULT;
- return 0;
- }
- static ssize_t ocfs2_control_validate_protocol(struct file *file,
- const char __user *buf,
- size_t count)
- {
- ssize_t ret;
- char kbuf[OCFS2_CONTROL_PROTO_LEN];
- ret = ocfs2_control_cfu(kbuf, OCFS2_CONTROL_PROTO_LEN,
- buf, count);
- if (ret)
- return ret;
- if (strncmp(kbuf, OCFS2_CONTROL_PROTO, OCFS2_CONTROL_PROTO_LEN))
- return -EINVAL;
- ocfs2_control_set_handshake_state(file,
- OCFS2_CONTROL_HANDSHAKE_PROTOCOL);
- return count;
- }
- static void ocfs2_control_send_down(const char *uuid,
- int nodenum)
- {
- struct ocfs2_live_connection *c;
- mutex_lock(&ocfs2_control_lock);
- c = ocfs2_connection_find(uuid);
- if (c) {
- BUG_ON(c->oc_conn == NULL);
- c->oc_conn->cc_recovery_handler(nodenum,
- c->oc_conn->cc_recovery_data);
- }
- mutex_unlock(&ocfs2_control_lock);
- }
- /*
- * Called whenever configuration elements are sent to /dev/ocfs2_control.
- * If all configuration elements are present, try to set the global
- * values. If not, return -EAGAIN. If there is a problem, return a
- * different error.
- */
- static int ocfs2_control_install_private(struct file *file)
- {
- int rc = 0;
- int set_p = 1;
- struct ocfs2_control_private *p = file->private_data;
- BUG_ON(p->op_state != OCFS2_CONTROL_HANDSHAKE_PROTOCOL);
- if (p->op_this_node < 0)
- set_p = 0;
- mutex_lock(&ocfs2_control_lock);
- if (ocfs2_control_this_node < 0) {
- if (set_p)
- ocfs2_control_this_node = p->op_this_node;
- } else if (ocfs2_control_this_node != p->op_this_node)
- rc = -EINVAL;
- mutex_unlock(&ocfs2_control_lock);
- if (!rc && set_p) {
- /* We set the global values successfully */
- atomic_inc(&ocfs2_control_opened);
- ocfs2_control_set_handshake_state(file,
- OCFS2_CONTROL_HANDSHAKE_VALID);
- }
- return rc;
- }
- static int ocfs2_control_do_setnode_msg(struct file *file,
- struct ocfs2_control_message_setn *msg)
- {
- long nodenum;
- char *ptr = NULL;
- struct ocfs2_control_private *p = file->private_data;
- if (ocfs2_control_get_handshake_state(file) !=
- OCFS2_CONTROL_HANDSHAKE_PROTOCOL)
- return -EINVAL;
- if (strncmp(msg->tag, OCFS2_CONTROL_MESSAGE_SETNODE_OP,
- OCFS2_CONTROL_MESSAGE_OP_LEN))
- return -EINVAL;
- if ((msg->space != ' ') || (msg->newline != '\n'))
- return -EINVAL;
- msg->space = msg->newline = '\0';
- nodenum = simple_strtol(msg->nodestr, &ptr, 16);
- if (!ptr || *ptr)
- return -EINVAL;
- if ((nodenum == LONG_MIN) || (nodenum == LONG_MAX) ||
- (nodenum > INT_MAX) || (nodenum < 0))
- return -ERANGE;
- p->op_this_node = nodenum;
- return ocfs2_control_install_private(file);
- }
- static int ocfs2_control_do_down_msg(struct file *file,
- struct ocfs2_control_message_down *msg)
- {
- long nodenum;
- char *p = NULL;
- if (ocfs2_control_get_handshake_state(file) !=
- OCFS2_CONTROL_HANDSHAKE_VALID)
- return -EINVAL;
- if (strncmp(msg->tag, OCFS2_CONTROL_MESSAGE_DOWN_OP,
- OCFS2_CONTROL_MESSAGE_OP_LEN))
- return -EINVAL;
- if ((msg->space1 != ' ') || (msg->space2 != ' ') ||
- (msg->newline != '\n'))
- return -EINVAL;
- msg->space1 = msg->space2 = msg->newline = '\0';
- nodenum = simple_strtol(msg->nodestr, &p, 16);
- if (!p || *p)
- return -EINVAL;
- if ((nodenum == LONG_MIN) || (nodenum == LONG_MAX) ||
- (nodenum > INT_MAX) || (nodenum < 0))
- return -ERANGE;
- ocfs2_control_send_down(msg->uuid, nodenum);
- return 0;
- }
- static ssize_t ocfs2_control_message(struct file *file,
- const char __user *buf,
- size_t count)
- {
- ssize_t ret;
- union ocfs2_control_message msg;
- /* Try to catch padding issues */
- WARN_ON(offsetof(struct ocfs2_control_message_down, uuid) !=
- (sizeof(msg.u_down.tag) + sizeof(msg.u_down.space1)));
- memset(&msg, 0, sizeof(union ocfs2_control_message));
- ret = ocfs2_control_cfu(&msg, count, buf, count);
- if (ret)
- goto out;
- if ((count == OCFS2_CONTROL_MESSAGE_SETNODE_TOTAL_LEN) &&
- !strncmp(msg.tag, OCFS2_CONTROL_MESSAGE_SETNODE_OP,
- OCFS2_CONTROL_MESSAGE_OP_LEN))
- ret = ocfs2_control_do_setnode_msg(file, &msg.u_setn);
- else if ((count == OCFS2_CONTROL_MESSAGE_DOWN_TOTAL_LEN) &&
- !strncmp(msg.tag, OCFS2_CONTROL_MESSAGE_DOWN_OP,
- OCFS2_CONTROL_MESSAGE_OP_LEN))
- ret = ocfs2_control_do_down_msg(file, &msg.u_down);
- else
- ret = -EINVAL;
- out:
- return ret ? ret : count;
- }
- static ssize_t ocfs2_control_write(struct file *file,
- const char __user *buf,
- size_t count,
- loff_t *ppos)
- {
- ssize_t ret;
- switch (ocfs2_control_get_handshake_state(file)) {
- case OCFS2_CONTROL_HANDSHAKE_INVALID:
- ret = -EINVAL;
- break;
- case OCFS2_CONTROL_HANDSHAKE_READ:
- ret = ocfs2_control_validate_protocol(file, buf,
- count);
- break;
- case OCFS2_CONTROL_HANDSHAKE_PROTOCOL:
- case OCFS2_CONTROL_HANDSHAKE_VALID:
- ret = ocfs2_control_message(file, buf, count);
- break;
- default:
- BUG();
- ret = -EIO;
- break;
- }
- return ret;
- }
- /*
- * This is a naive version. If we ever have a new protocol, we'll expand
- * it. Probably using seq_file.
- */
- static ssize_t ocfs2_control_read(struct file *file,
- char __user *buf,
- size_t count,
- loff_t *ppos)
- {
- char *proto_string = OCFS2_CONTROL_PROTO;
- size_t to_write = 0;
- if (*ppos >= OCFS2_CONTROL_PROTO_LEN)
- return 0;
- to_write = OCFS2_CONTROL_PROTO_LEN - *ppos;
- if (to_write > count)
- to_write = count;
- if (copy_to_user(buf, proto_string + *ppos, to_write))
- return -EFAULT;
- *ppos += to_write;
- /* Have we read the whole protocol list? */
- if (*ppos >= OCFS2_CONTROL_PROTO_LEN)
- ocfs2_control_set_handshake_state(file,
- OCFS2_CONTROL_HANDSHAKE_READ);
- return to_write;
- }
- static int ocfs2_control_release(struct inode *inode, struct file *file)
- {
- struct ocfs2_control_private *p = file->private_data;
- mutex_lock(&ocfs2_control_lock);
- if (ocfs2_control_get_handshake_state(file) !=
- OCFS2_CONTROL_HANDSHAKE_VALID)
- goto out;
- if (atomic_dec_and_test(&ocfs2_control_opened)) {
- if (!list_empty(&ocfs2_live_connection_list)) {
- /* XXX: Do bad things! */
- printk(KERN_ERR
- "ocfs2: Unexpected release of ocfs2_control!\n"
- " Loss of cluster connection requires "
- "an emergency restart!\n");
- emergency_restart();
- }
- /* Last valid close clears the node number */
- ocfs2_control_this_node = -1;
- }
- out:
- list_del_init(&p->op_list);
- file->private_data = NULL;
- mutex_unlock(&ocfs2_control_lock);
- kfree(p);
- return 0;
- }
- static int ocfs2_control_open(struct inode *inode, struct file *file)
- {
- struct ocfs2_control_private *p;
- p = kzalloc(sizeof(struct ocfs2_control_private), GFP_KERNEL);
- if (!p)
- return -ENOMEM;
- p->op_this_node = -1;
- mutex_lock(&ocfs2_control_lock);
- file->private_data = p;
- list_add(&p->op_list, &ocfs2_control_private_list);
- mutex_unlock(&ocfs2_control_lock);
- return 0;
- }
- static const struct file_operations ocfs2_control_fops = {
- .open = ocfs2_control_open,
- .release = ocfs2_control_release,
- .read = ocfs2_control_read,
- .write = ocfs2_control_write,
- .owner = THIS_MODULE,
- };
- struct miscdevice ocfs2_control_device = {
- .minor = MISC_DYNAMIC_MINOR,
- .name = "ocfs2_control",
- .fops = &ocfs2_control_fops,
- };
- static int ocfs2_control_init(void)
- {
- int rc;
- atomic_set(&ocfs2_control_opened, 0);
- rc = misc_register(&ocfs2_control_device);
- if (rc)
- printk(KERN_ERR
- "ocfs2: Unable to register ocfs2_control device "
- "(errno %d)\n",
- -rc);
- return rc;
- }
- static void ocfs2_control_exit(void)
- {
- int rc;
- rc = misc_deregister(&ocfs2_control_device);
- if (rc)
- printk(KERN_ERR
- "ocfs2: Unable to deregister ocfs2_control device "
- "(errno %d)\n",
- -rc);
- }
- static int __init user_stack_init(void)
- {
- return ocfs2_control_init();
- }
- static void __exit user_stack_exit(void)
- {
- ocfs2_control_exit();
- }
- MODULE_AUTHOR("Oracle");
- MODULE_DESCRIPTION("ocfs2 driver for userspace cluster stacks");
- MODULE_LICENSE("GPL");
- module_init(user_stack_init);
- module_exit(user_stack_exit);
|