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DEFINITIONS
This source file includes following definitions.
- ocfs2_control_set_handshake_state
- ocfs2_control_get_handshake_state
- ocfs2_connection_find
- ocfs2_live_connection_new
- ocfs2_live_connection_drop
- ocfs2_control_cfu
- ocfs2_control_validate_protocol
- ocfs2_control_send_down
- ocfs2_control_install_private
- ocfs2_control_get_this_node
- ocfs2_control_do_setnode_msg
- ocfs2_control_do_setversion_msg
- ocfs2_control_do_down_msg
- ocfs2_control_message
- ocfs2_control_write
- ocfs2_control_read
- ocfs2_control_release
- ocfs2_control_open
- ocfs2_control_init
- ocfs2_control_exit
- fsdlm_astarg_to_lksb
- fsdlm_lock_ast_wrapper
- fsdlm_blocking_ast_wrapper
- user_dlm_lock
- user_dlm_unlock
- user_dlm_lock_status
- user_dlm_lvb
- user_dlm_dump_lksb
- user_plock
- fs_protocol_compare
- user_cluster_connect
- user_cluster_disconnect
- user_cluster_this_node
- ocfs2_user_plugin_init
- ocfs2_user_plugin_exit
/* -*- 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/smp_lock.h>
#include <linux/reboot.h>
#include <asm/uaccess.h>
#include "ocfs2.h" /* For struct ocfs2_lock_res */
#include "stackglue.h"
#include <linux/dlm_plock.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 has three 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.
*
* Next comes the "SETV" message. It has the following syntax:
*
* SETV<space><2-char-hex-major><space><2-char-hex-minor><newline>
*
* This is 11 characters.
*
* The "SETV" message sets the filesystem locking protocol version as
* negotiated by the client. The client negotiates based on the maximum
* version advertised in /sys/fs/ocfs2/max_locking_protocol. The major
* number from the "SETV" message must match
* ocfs2_user_plugin.sp_proto->lp_max_version.pv_major, and the minor number
* must be less than or equal to ...->lp_max_version.pv_minor.
*
* Once this information has been set, mounts will be allowed. From this
* point on, 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_SETVERSION_OP "SETV"
#define OCFS2_CONTROL_MESSAGE_SETVERSION_TOTAL_LEN 11
#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_VERNUM_LEN 2
#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;
struct ocfs2_protocol_version op_proto;
};
/* 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;
};
/* SETV<space><2-char-hex-major><space><2-char-hex-minor><newline> */
struct ocfs2_control_message_setv {
char tag[OCFS2_CONTROL_MESSAGE_OP_LEN];
char space1;
char major[OCFS2_CONTROL_MESSAGE_VERNUM_LEN];
char space2;
char minor[OCFS2_CONTROL_MESSAGE_VERNUM_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_setv u_setv;
struct ocfs2_control_message_down u_down;
};
static struct ocfs2_stack_plugin ocfs2_user_plugin;
static atomic_t ocfs2_control_opened;
static int ocfs2_control_this_node = -1;
static struct ocfs2_protocol_version running_proto;
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 there is a problem, return an error. Skip any missing
* elements, and only bump ocfs2_control_opened when we have all elements
* and are successful.
*/
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);
mutex_lock(&ocfs2_control_lock);
if (p->op_this_node < 0) {
set_p = 0;
} else if ((ocfs2_control_this_node >= 0) &&
(ocfs2_control_this_node != p->op_this_node)) {
rc = -EINVAL;
goto out_unlock;
}
if (!p->op_proto.pv_major) {
set_p = 0;
} else if (!list_empty(&ocfs2_live_connection_list) &&
((running_proto.pv_major != p->op_proto.pv_major) ||
(running_proto.pv_minor != p->op_proto.pv_minor))) {
rc = -EINVAL;
goto out_unlock;
}
if (set_p) {
ocfs2_control_this_node = p->op_this_node;
running_proto.pv_major = p->op_proto.pv_major;
running_proto.pv_minor = p->op_proto.pv_minor;
}
out_unlock:
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_get_this_node(void)
{
int rc;
mutex_lock(&ocfs2_control_lock);
if (ocfs2_control_this_node < 0)
rc = -EINVAL;
else
rc = ocfs2_control_this_node;
mutex_unlock(&ocfs2_control_lock);
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_setversion_msg(struct file *file,
struct ocfs2_control_message_setv *msg)
{
long major, minor;
char *ptr = NULL;
struct ocfs2_control_private *p = file->private_data;
struct ocfs2_protocol_version *max =
&ocfs2_user_plugin.sp_proto->lp_max_version;
if (ocfs2_control_get_handshake_state(file) !=
OCFS2_CONTROL_HANDSHAKE_PROTOCOL)
return -EINVAL;
if (strncmp(msg->tag, OCFS2_CONTROL_MESSAGE_SETVERSION_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';
major = simple_strtol(msg->major, &ptr, 16);
if (!ptr || *ptr)
return -EINVAL;
minor = simple_strtol(msg->minor, &ptr, 16);
if (!ptr || *ptr)
return -EINVAL;
/*
* The major must be between 1 and 255, inclusive. The minor
* must be between 0 and 255, inclusive. The version passed in
* must be within the maximum version supported by the filesystem.
*/
if ((major == LONG_MIN) || (major == LONG_MAX) ||
(major > (u8)-1) || (major < 1))
return -ERANGE;
if ((minor == LONG_MIN) || (minor == LONG_MAX) ||
(minor > (u8)-1) || (minor < 0))
return -ERANGE;
if ((major != max->pv_major) ||
(minor > max->pv_minor))
return -EINVAL;
p->op_proto.pv_major = major;
p->op_proto.pv_minor = minor;
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_SETVERSION_TOTAL_LEN) &&
!strncmp(msg.tag, OCFS2_CONTROL_MESSAGE_SETVERSION_OP,
OCFS2_CONTROL_MESSAGE_OP_LEN))
ret = ocfs2_control_do_setversion_msg(file, &msg.u_setv);
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)
{
ssize_t ret;
ret = simple_read_from_buffer(buf, count, ppos,
OCFS2_CONTROL_PROTO, OCFS2_CONTROL_PROTO_LEN);
/* Have we read the whole protocol list? */
if (ret > 0 && *ppos >= OCFS2_CONTROL_PROTO_LEN)
ocfs2_control_set_handshake_state(file,
OCFS2_CONTROL_HANDSHAKE_READ);
return ret;
}
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 and resets
* the locking protocol version
*/
ocfs2_control_this_node = -1;
running_proto.pv_major = 0;
running_proto.pv_major = 0;
}
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;
lock_kernel();
mutex_lock(&ocfs2_control_lock);
file->private_data = p;
list_add(&p->op_list, &ocfs2_control_private_list);
mutex_unlock(&ocfs2_control_lock);
unlock_kernel();
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,
};
static 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 struct dlm_lksb *fsdlm_astarg_to_lksb(void *astarg)
{
struct ocfs2_lock_res *res = astarg;
return &res->l_lksb.lksb_fsdlm;
}
static void fsdlm_lock_ast_wrapper(void *astarg)
{
struct dlm_lksb *lksb = fsdlm_astarg_to_lksb(astarg);
int status = lksb->sb_status;
BUG_ON(ocfs2_user_plugin.sp_proto == NULL);
/*
* For now we're punting on the issue of other non-standard errors
* where we can't tell if the unlock_ast or lock_ast should be called.
* The main "other error" that's possible is EINVAL which means the
* function was called with invalid args, which shouldn't be possible
* since the caller here is under our control. Other non-standard
* errors probably fall into the same category, or otherwise are fatal
* which means we can't carry on anyway.
*/
if (status == -DLM_EUNLOCK || status == -DLM_ECANCEL)
ocfs2_user_plugin.sp_proto->lp_unlock_ast(astarg, 0);
else
ocfs2_user_plugin.sp_proto->lp_lock_ast(astarg);
}
static void fsdlm_blocking_ast_wrapper(void *astarg, int level)
{
BUG_ON(ocfs2_user_plugin.sp_proto == NULL);
ocfs2_user_plugin.sp_proto->lp_blocking_ast(astarg, level);
}
static int user_dlm_lock(struct ocfs2_cluster_connection *conn,
int mode,
union ocfs2_dlm_lksb *lksb,
u32 flags,
void *name,
unsigned int namelen,
void *astarg)
{
int ret;
if (!lksb->lksb_fsdlm.sb_lvbptr)
lksb->lksb_fsdlm.sb_lvbptr = (char *)lksb +
sizeof(struct dlm_lksb);
ret = dlm_lock(conn->cc_lockspace, mode, &lksb->lksb_fsdlm,
flags|DLM_LKF_NODLCKWT, name, namelen, 0,
fsdlm_lock_ast_wrapper, astarg,
fsdlm_blocking_ast_wrapper);
return ret;
}
static int user_dlm_unlock(struct ocfs2_cluster_connection *conn,
union ocfs2_dlm_lksb *lksb,
u32 flags,
void *astarg)
{
int ret;
ret = dlm_unlock(conn->cc_lockspace, lksb->lksb_fsdlm.sb_lkid,
flags, &lksb->lksb_fsdlm, astarg);
return ret;
}
static int user_dlm_lock_status(union ocfs2_dlm_lksb *lksb)
{
return lksb->lksb_fsdlm.sb_status;
}
static void *user_dlm_lvb(union ocfs2_dlm_lksb *lksb)
{
return (void *)(lksb->lksb_fsdlm.sb_lvbptr);
}
static void user_dlm_dump_lksb(union ocfs2_dlm_lksb *lksb)
{
}
static int user_plock(struct ocfs2_cluster_connection *conn,
u64 ino,
struct file *file,
int cmd,
struct file_lock *fl)
{
/*
* This more or less just demuxes the plock request into any
* one of three dlm calls.
*
* Internally, fs/dlm will pass these to a misc device, which
* a userspace daemon will read and write to.
*
* For now, cancel requests (which happen internally only),
* are turned into unlocks. Most of this function taken from
* gfs2_lock.
*/
if (cmd == F_CANCELLK) {
cmd = F_SETLK;
fl->fl_type = F_UNLCK;
}
if (IS_GETLK(cmd))
return dlm_posix_get(conn->cc_lockspace, ino, file, fl);
else if (fl->fl_type == F_UNLCK)
return dlm_posix_unlock(conn->cc_lockspace, ino, file, fl);
else
return dlm_posix_lock(conn->cc_lockspace, ino, file, cmd, fl);
}
/*
* Compare a requested locking protocol version against the current one.
*
* If the major numbers are different, they are incompatible.
* If the current minor is greater than the request, they are incompatible.
* If the current minor is less than or equal to the request, they are
* compatible, and the requester should run at the current minor version.
*/
static int fs_protocol_compare(struct ocfs2_protocol_version *existing,
struct ocfs2_protocol_version *request)
{
if (existing->pv_major != request->pv_major)
return 1;
if (existing->pv_minor > request->pv_minor)
return 1;
if (existing->pv_minor < request->pv_minor)
request->pv_minor = existing->pv_minor;
return 0;
}
static int user_cluster_connect(struct ocfs2_cluster_connection *conn)
{
dlm_lockspace_t *fsdlm;
struct ocfs2_live_connection *control;
int rc = 0;
BUG_ON(conn == NULL);
rc = ocfs2_live_connection_new(conn, &control);
if (rc)
goto out;
/*
* running_proto must have been set before we allowed any mounts
* to proceed.
*/
if (fs_protocol_compare(&running_proto, &conn->cc_version)) {
printk(KERN_ERR
"Unable to mount with fs locking protocol version "
"%u.%u because the userspace control daemon has "
"negotiated %u.%u\n",
conn->cc_version.pv_major, conn->cc_version.pv_minor,
running_proto.pv_major, running_proto.pv_minor);
rc = -EPROTO;
ocfs2_live_connection_drop(control);
goto out;
}
rc = dlm_new_lockspace(conn->cc_name, strlen(conn->cc_name),
&fsdlm, DLM_LSFL_FS, DLM_LVB_LEN);
if (rc) {
ocfs2_live_connection_drop(control);
goto out;
}
conn->cc_private = control;
conn->cc_lockspace = fsdlm;
out:
return rc;
}
static int user_cluster_disconnect(struct ocfs2_cluster_connection *conn)
{
dlm_release_lockspace(conn->cc_lockspace, 2);
conn->cc_lockspace = NULL;
ocfs2_live_connection_drop(conn->cc_private);
conn->cc_private = NULL;
return 0;
}
static int user_cluster_this_node(unsigned int *this_node)
{
int rc;
rc = ocfs2_control_get_this_node();
if (rc < 0)
return rc;
*this_node = rc;
return 0;
}
static struct ocfs2_stack_operations ocfs2_user_plugin_ops = {
.connect = user_cluster_connect,
.disconnect = user_cluster_disconnect,
.this_node = user_cluster_this_node,
.dlm_lock = user_dlm_lock,
.dlm_unlock = user_dlm_unlock,
.lock_status = user_dlm_lock_status,
.lock_lvb = user_dlm_lvb,
.plock = user_plock,
.dump_lksb = user_dlm_dump_lksb,
};
static struct ocfs2_stack_plugin ocfs2_user_plugin = {
.sp_name = "user",
.sp_ops = &ocfs2_user_plugin_ops,
.sp_owner = THIS_MODULE,
};
static int __init ocfs2_user_plugin_init(void)
{
int rc;
rc = ocfs2_control_init();
if (!rc) {
rc = ocfs2_stack_glue_register(&ocfs2_user_plugin);
if (rc)
ocfs2_control_exit();
}
return rc;
}
static void __exit ocfs2_user_plugin_exit(void)
{
ocfs2_stack_glue_unregister(&ocfs2_user_plugin);
ocfs2_control_exit();
}
MODULE_AUTHOR("Oracle");
MODULE_DESCRIPTION("ocfs2 driver for userspace cluster stacks");
MODULE_LICENSE("GPL");
module_init(ocfs2_user_plugin_init);
module_exit(ocfs2_user_plugin_exit);