git.oblomov.eu Git - linux-2.6/blob - fs/ocfs2/stack_user.c

   1 /* -*- mode: c; c-basic-offset: 8; -*-
   2  * vim: noexpandtab sw=8 ts=8 sts=0:
   3  *
   4  * stack_user.c
   5  *
   6  * Code which interfaces ocfs2 with fs/dlm and a userspace stack.
   7  *
   8  * Copyright (C) 2007 Oracle.  All rights reserved.
   9  *
  10  * This program is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU General Public
  12  * License as published by the Free Software Foundation, version 2.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * General Public License for more details.
  18  */
  19
  20 #include <linux/module.h>
  21 #include <linux/fs.h>
  22 #include <linux/miscdevice.h>
  23 #include <linux/mutex.h>
  24 #include <linux/smp_lock.h>
  25 #include <linux/reboot.h>
  26 #include <asm/uaccess.h>
  27
  28 #include "ocfs2.h"  /* For struct ocfs2_lock_res */
  29 #include "stackglue.h"
  30
  31
  32 /*
  33  * The control protocol starts with a handshake.  Until the handshake
  34  * is complete, the control device will fail all write(2)s.
  35  *
  36  * The handshake is simple.  First, the client reads until EOF.  Each line
  37  * of output is a supported protocol tag.  All protocol tags are a single
  38  * character followed by a two hex digit version number.  Currently the
  39  * only things supported is T01, for "Text-base version 0x01".  Next, the
  40  * client writes the version they would like to use, including the newline.
  41  * Thus, the protocol tag is 'T01\n'.  If the version tag written is
  42  * unknown, -EINVAL is returned.  Once the negotiation is complete, the
  43  * client can start sending messages.
  44  *
  45  * The T01 protocol has three messages.  First is the "SETN" message.
  46  * It has the following syntax:
  47  *
  48  *  SETN<space><8-char-hex-nodenum><newline>
  49  *
  50  * This is 14 characters.
  51  *
  52  * The "SETN" message must be the first message following the protocol.
  53  * It tells ocfs2_control the local node number.
  54  *
  55  * Next comes the "SETV" message.  It has the following syntax:
  56  *
  57  *  SETV<space><2-char-hex-major><space><2-char-hex-minor><newline>
  58  *
  59  * This is 11 characters.
  60  *
  61  * The "SETV" message sets the filesystem locking protocol version as
  62  * negotiated by the client.  The client negotiates based on the maximum
  63  * version advertised in /sys/fs/ocfs2/max_locking_protocol.  The major
  64  * number from the "SETV" message must match
  65  * ocfs2_user_plugin.sp_proto->lp_max_version.pv_major, and the minor number
  66  * must be less than or equal to ...->lp_max_version.pv_minor.
  67  *
  68  * Once this information has been set, mounts will be allowed.  From this
  69  * point on, the "DOWN" message can be sent for node down notification.
  70  * It has the following syntax:
  71  *
  72  *  DOWN<space><32-char-cap-hex-uuid><space><8-char-hex-nodenum><newline>
  73  *
  74  * eg:
  75  *
  76  *  DOWN 632A924FDD844190BDA93C0DF6B94899 00000001\n
  77  *
  78  * This is 47 characters.
  79  */
  80
  81 /*
  82  * Whether or not the client has done the handshake.
  83  * For now, we have just one protocol version.
  84  */
  85 #define OCFS2_CONTROL_PROTO                     "T01\n"
  86 #define OCFS2_CONTROL_PROTO_LEN                 4
  87
  88 /* Handshake states */
  89 #define OCFS2_CONTROL_HANDSHAKE_INVALID         (0)
  90 #define OCFS2_CONTROL_HANDSHAKE_READ            (1)
  91 #define OCFS2_CONTROL_HANDSHAKE_PROTOCOL        (2)
  92 #define OCFS2_CONTROL_HANDSHAKE_VALID           (3)
  93
  94 /* Messages */
  95 #define OCFS2_CONTROL_MESSAGE_OP_LEN            4
  96 #define OCFS2_CONTROL_MESSAGE_SETNODE_OP        "SETN"
  97 #define OCFS2_CONTROL_MESSAGE_SETNODE_TOTAL_LEN 14
  98 #define OCFS2_CONTROL_MESSAGE_SETVERSION_OP     "SETV"
  99 #define OCFS2_CONTROL_MESSAGE_SETVERSION_TOTAL_LEN      11
 100 #define OCFS2_CONTROL_MESSAGE_DOWN_OP           "DOWN"
 101 #define OCFS2_CONTROL_MESSAGE_DOWN_TOTAL_LEN    47
 102 #define OCFS2_TEXT_UUID_LEN                     32
 103 #define OCFS2_CONTROL_MESSAGE_VERNUM_LEN        2
 104 #define OCFS2_CONTROL_MESSAGE_NODENUM_LEN       8
 105
 106 /*
 107  * ocfs2_live_connection is refcounted because the filesystem and
 108  * miscdevice sides can detach in different order.  Let's just be safe.
 109  */
 110 struct ocfs2_live_connection {
 111         struct list_head                oc_list;
 112         struct ocfs2_cluster_connection *oc_conn;
 113 };
 114
 115 struct ocfs2_control_private {
 116         struct list_head op_list;
 117         int op_state;
 118         int op_this_node;
 119         struct ocfs2_protocol_version op_proto;
 120 };
 121
 122 /* SETN<space><8-char-hex-nodenum><newline> */
 123 struct ocfs2_control_message_setn {
 124         char    tag[OCFS2_CONTROL_MESSAGE_OP_LEN];
 125         char    space;
 126         char    nodestr[OCFS2_CONTROL_MESSAGE_NODENUM_LEN];
 127         char    newline;
 128 };
 129
 130 /* SETV<space><2-char-hex-major><space><2-char-hex-minor><newline> */
 131 struct ocfs2_control_message_setv {
 132         char    tag[OCFS2_CONTROL_MESSAGE_OP_LEN];
 133         char    space1;
 134         char    major[OCFS2_CONTROL_MESSAGE_VERNUM_LEN];
 135         char    space2;
 136         char    minor[OCFS2_CONTROL_MESSAGE_VERNUM_LEN];
 137         char    newline;
 138 };
 139
 140 /* DOWN<space><32-char-cap-hex-uuid><space><8-char-hex-nodenum><newline> */
 141 struct ocfs2_control_message_down {
 142         char    tag[OCFS2_CONTROL_MESSAGE_OP_LEN];
 143         char    space1;
 144         char    uuid[OCFS2_TEXT_UUID_LEN];
 145         char    space2;
 146         char    nodestr[OCFS2_CONTROL_MESSAGE_NODENUM_LEN];
 147         char    newline;
 148 };
 149
 150 union ocfs2_control_message {
 151         char                                    tag[OCFS2_CONTROL_MESSAGE_OP_LEN];
 152         struct ocfs2_control_message_setn       u_setn;
 153         struct ocfs2_control_message_setv       u_setv;
 154         struct ocfs2_control_message_down       u_down;
 155 };
 156
 157 static struct ocfs2_stack_plugin ocfs2_user_plugin;
 158
 159 static atomic_t ocfs2_control_opened;
 160 static int ocfs2_control_this_node = -1;
 161 static struct ocfs2_protocol_version running_proto;
 162
 163 static LIST_HEAD(ocfs2_live_connection_list);
 164 static LIST_HEAD(ocfs2_control_private_list);
 165 static DEFINE_MUTEX(ocfs2_control_lock);
 166
 167 static inline void ocfs2_control_set_handshake_state(struct file *file,
 168                                                      int state)
 169 {
 170         struct ocfs2_control_private *p = file->private_data;
 171         p->op_state = state;
 172 }
 173
 174 static inline int ocfs2_control_get_handshake_state(struct file *file)
 175 {
 176         struct ocfs2_control_private *p = file->private_data;
 177         return p->op_state;
 178 }
 179
 180 static struct ocfs2_live_connection *ocfs2_connection_find(const char *name)
 181 {
 182         size_t len = strlen(name);
 183         struct ocfs2_live_connection *c;
 184
 185         BUG_ON(!mutex_is_locked(&ocfs2_control_lock));
 186
 187         list_for_each_entry(c, &ocfs2_live_connection_list, oc_list) {
 188                 if ((c->oc_conn->cc_namelen == len) &&
 189                     !strncmp(c->oc_conn->cc_name, name, len))
 190                         return c;
 191         }
 192
 193         return c;
 194 }
 195
 196 /*
 197  * ocfs2_live_connection structures are created underneath the ocfs2
 198  * mount path.  Since the VFS prevents multiple calls to
 199  * fill_super(), we can't get dupes here.
 200  */
 201 static int ocfs2_live_connection_new(struct ocfs2_cluster_connection *conn,
 202                                      struct ocfs2_live_connection **c_ret)
 203 {
 204         int rc = 0;
 205         struct ocfs2_live_connection *c;
 206
 207         c = kzalloc(sizeof(struct ocfs2_live_connection), GFP_KERNEL);
 208         if (!c)
 209                 return -ENOMEM;
 210
 211         mutex_lock(&ocfs2_control_lock);
 212         c->oc_conn = conn;
 213
 214         if (atomic_read(&ocfs2_control_opened))
 215                 list_add(&c->oc_list, &ocfs2_live_connection_list);
 216         else {
 217                 printk(KERN_ERR
 218                        "ocfs2: Userspace control daemon is not present\n");
 219                 rc = -ESRCH;
 220         }
 221
 222         mutex_unlock(&ocfs2_control_lock);
 223
 224         if (!rc)
 225                 *c_ret = c;
 226         else
 227                 kfree(c);
 228
 229         return rc;
 230 }
 231
 232 /*
 233  * This function disconnects the cluster connection from ocfs2_control.
 234  * Afterwards, userspace can't affect the cluster connection.
 235  */
 236 static void ocfs2_live_connection_drop(struct ocfs2_live_connection *c)
 237 {
 238         mutex_lock(&ocfs2_control_lock);
 239         list_del_init(&c->oc_list);
 240         c->oc_conn = NULL;
 241         mutex_unlock(&ocfs2_control_lock);
 242
 243         kfree(c);
 244 }
 245
 246 static int ocfs2_control_cfu(void *target, size_t target_len,
 247                              const char __user *buf, size_t count)
 248 {
 249         /* The T01 expects write(2) calls to have exactly one command */
 250         if ((count != target_len) ||
 251             (count > sizeof(union ocfs2_control_message)))
 252                 return -EINVAL;
 253
 254         if (copy_from_user(target, buf, target_len))
 255                 return -EFAULT;
 256
 257         return 0;
 258 }
 259
 260 static ssize_t ocfs2_control_validate_protocol(struct file *file,
 261                                                const char __user *buf,
 262                                                size_t count)
 263 {
 264         ssize_t ret;
 265         char kbuf[OCFS2_CONTROL_PROTO_LEN];
 266
 267         ret = ocfs2_control_cfu(kbuf, OCFS2_CONTROL_PROTO_LEN,
 268                                 buf, count);
 269         if (ret)
 270                 return ret;
 271
 272         if (strncmp(kbuf, OCFS2_CONTROL_PROTO, OCFS2_CONTROL_PROTO_LEN))
 273                 return -EINVAL;
 274
 275         ocfs2_control_set_handshake_state(file,
 276                                           OCFS2_CONTROL_HANDSHAKE_PROTOCOL);
 277
 278         return count;
 279 }
 280
 281 static void ocfs2_control_send_down(const char *uuid,
 282                                     int nodenum)
 283 {
 284         struct ocfs2_live_connection *c;
 285
 286         mutex_lock(&ocfs2_control_lock);
 287
 288         c = ocfs2_connection_find(uuid);
 289         if (c) {
 290                 BUG_ON(c->oc_conn == NULL);
 291                 c->oc_conn->cc_recovery_handler(nodenum,
 292                                                 c->oc_conn->cc_recovery_data);
 293         }
 294
 295         mutex_unlock(&ocfs2_control_lock);
 296 }
 297
 298 /*
 299  * Called whenever configuration elements are sent to /dev/ocfs2_control.
 300  * If all configuration elements are present, try to set the global
 301  * values.  If there is a problem, return an error.  Skip any missing
 302  * elements, and only bump ocfs2_control_opened when we have all elements
 303  * and are successful.
 304  */
 305 static int ocfs2_control_install_private(struct file *file)
 306 {
 307         int rc = 0;
 308         int set_p = 1;
 309         struct ocfs2_control_private *p = file->private_data;
 310
 311         BUG_ON(p->op_state != OCFS2_CONTROL_HANDSHAKE_PROTOCOL);
 312
 313         mutex_lock(&ocfs2_control_lock);
 314
 315         if (p->op_this_node < 0) {
 316                 set_p = 0;
 317         } else if ((ocfs2_control_this_node >= 0) &&
 318                    (ocfs2_control_this_node != p->op_this_node)) {
 319                 rc = -EINVAL;
 320                 goto out_unlock;
 321         }
 322
 323         if (!p->op_proto.pv_major) {
 324                 set_p = 0;
 325         } else if (!list_empty(&ocfs2_live_connection_list) &&
 326                    ((running_proto.pv_major != p->op_proto.pv_major) ||
 327                     (running_proto.pv_minor != p->op_proto.pv_minor))) {
 328                 rc = -EINVAL;
 329                 goto out_unlock;
 330         }
 331
 332         if (set_p) {
 333                 ocfs2_control_this_node = p->op_this_node;
 334                 running_proto.pv_major = p->op_proto.pv_major;
 335                 running_proto.pv_minor = p->op_proto.pv_minor;
 336         }
 337
 338 out_unlock:
 339         mutex_unlock(&ocfs2_control_lock);
 340
 341         if (!rc && set_p) {
 342                 /* We set the global values successfully */
 343                 atomic_inc(&ocfs2_control_opened);
 344                 ocfs2_control_set_handshake_state(file,
 345                                         OCFS2_CONTROL_HANDSHAKE_VALID);
 346         }
 347
 348         return rc;
 349 }
 350
 351 static int ocfs2_control_get_this_node(void)
 352 {
 353         int rc;
 354
 355         mutex_lock(&ocfs2_control_lock);
 356         if (ocfs2_control_this_node < 0)
 357                 rc = -EINVAL;
 358         else
 359                 rc = ocfs2_control_this_node;
 360         mutex_unlock(&ocfs2_control_lock);
 361
 362         return rc;
 363 }
 364
 365 static int ocfs2_control_do_setnode_msg(struct file *file,
 366                                         struct ocfs2_control_message_setn *msg)
 367 {
 368         long nodenum;
 369         char *ptr = NULL;
 370         struct ocfs2_control_private *p = file->private_data;
 371
 372         if (ocfs2_control_get_handshake_state(file) !=
 373             OCFS2_CONTROL_HANDSHAKE_PROTOCOL)
 374                 return -EINVAL;
 375
 376         if (strncmp(msg->tag, OCFS2_CONTROL_MESSAGE_SETNODE_OP,
 377                     OCFS2_CONTROL_MESSAGE_OP_LEN))
 378                 return -EINVAL;
 379
 380         if ((msg->space != ' ') || (msg->newline != '\n'))
 381                 return -EINVAL;
 382         msg->space = msg->newline = '\0';
 383
 384         nodenum = simple_strtol(msg->nodestr, &ptr, 16);
 385         if (!ptr || *ptr)
 386                 return -EINVAL;
 387
 388         if ((nodenum == LONG_MIN) || (nodenum == LONG_MAX) ||
 389             (nodenum > INT_MAX) || (nodenum < 0))
 390                 return -ERANGE;
 391         p->op_this_node = nodenum;
 392
 393         return ocfs2_control_install_private(file);
 394 }
 395
 396 static int ocfs2_control_do_setversion_msg(struct file *file,
 397                                            struct ocfs2_control_message_setv *msg)
 398  {
 399         long major, minor;
 400         char *ptr = NULL;
 401         struct ocfs2_control_private *p = file->private_data;
 402         struct ocfs2_protocol_version *max =
 403                 &ocfs2_user_plugin.sp_proto->lp_max_version;
 404
 405         if (ocfs2_control_get_handshake_state(file) !=
 406             OCFS2_CONTROL_HANDSHAKE_PROTOCOL)
 407                 return -EINVAL;
 408
 409         if (strncmp(msg->tag, OCFS2_CONTROL_MESSAGE_SETVERSION_OP,
 410                     OCFS2_CONTROL_MESSAGE_OP_LEN))
 411                 return -EINVAL;
 412
 413         if ((msg->space1 != ' ') || (msg->space2 != ' ') ||
 414             (msg->newline != '\n'))
 415                 return -EINVAL;
 416         msg->space1 = msg->space2 = msg->newline = '\0';
 417
 418         major = simple_strtol(msg->major, &ptr, 16);
 419         if (!ptr || *ptr)
 420                 return -EINVAL;
 421         minor = simple_strtol(msg->minor, &ptr, 16);
 422         if (!ptr || *ptr)
 423                 return -EINVAL;
 424
 425         /*
 426          * The major must be between 1 and 255, inclusive.  The minor
 427          * must be between 0 and 255, inclusive.  The version passed in
 428          * must be within the maximum version supported by the filesystem.
 429          */
 430         if ((major == LONG_MIN) || (major == LONG_MAX) ||
 431             (major > (u8)-1) || (major < 1))
 432                 return -ERANGE;
 433         if ((minor == LONG_MIN) || (minor == LONG_MAX) ||
 434             (minor > (u8)-1) || (minor < 0))
 435                 return -ERANGE;
 436         if ((major != max->pv_major) ||
 437             (minor > max->pv_minor))
 438                 return -EINVAL;
 439
 440         p->op_proto.pv_major = major;
 441         p->op_proto.pv_minor = minor;
 442
 443         return ocfs2_control_install_private(file);
 444 }
 445
 446 static int ocfs2_control_do_down_msg(struct file *file,
 447                                      struct ocfs2_control_message_down *msg)
 448 {
 449         long nodenum;
 450         char *p = NULL;
 451
 452         if (ocfs2_control_get_handshake_state(file) !=
 453             OCFS2_CONTROL_HANDSHAKE_VALID)
 454                 return -EINVAL;
 455
 456         if (strncmp(msg->tag, OCFS2_CONTROL_MESSAGE_DOWN_OP,
 457                     OCFS2_CONTROL_MESSAGE_OP_LEN))
 458                 return -EINVAL;
 459
 460         if ((msg->space1 != ' ') || (msg->space2 != ' ') ||
 461             (msg->newline != '\n'))
 462                 return -EINVAL;
 463         msg->space1 = msg->space2 = msg->newline = '\0';
 464
 465         nodenum = simple_strtol(msg->nodestr, &p, 16);
 466         if (!p || *p)
 467                 return -EINVAL;
 468
 469         if ((nodenum == LONG_MIN) || (nodenum == LONG_MAX) ||
 470             (nodenum > INT_MAX) || (nodenum < 0))
 471                 return -ERANGE;
 472
 473         ocfs2_control_send_down(msg->uuid, nodenum);
 474
 475         return 0;
 476 }
 477
 478 static ssize_t ocfs2_control_message(struct file *file,
 479                                      const char __user *buf,
 480                                      size_t count)
 481 {
 482         ssize_t ret;
 483         union ocfs2_control_message msg;
 484
 485         /* Try to catch padding issues */
 486         WARN_ON(offsetof(struct ocfs2_control_message_down, uuid) !=
 487                 (sizeof(msg.u_down.tag) + sizeof(msg.u_down.space1)));
 488
 489         memset(&msg, 0, sizeof(union ocfs2_control_message));
 490         ret = ocfs2_control_cfu(&msg, count, buf, count);
 491         if (ret)
 492                 goto out;
 493
 494         if ((count == OCFS2_CONTROL_MESSAGE_SETNODE_TOTAL_LEN) &&
 495             !strncmp(msg.tag, OCFS2_CONTROL_MESSAGE_SETNODE_OP,
 496                      OCFS2_CONTROL_MESSAGE_OP_LEN))
 497                 ret = ocfs2_control_do_setnode_msg(file, &msg.u_setn);
 498         else if ((count == OCFS2_CONTROL_MESSAGE_SETVERSION_TOTAL_LEN) &&
 499                  !strncmp(msg.tag, OCFS2_CONTROL_MESSAGE_SETVERSION_OP,
 500                           OCFS2_CONTROL_MESSAGE_OP_LEN))
 501                 ret = ocfs2_control_do_setversion_msg(file, &msg.u_setv);
 502         else if ((count == OCFS2_CONTROL_MESSAGE_DOWN_TOTAL_LEN) &&
 503                  !strncmp(msg.tag, OCFS2_CONTROL_MESSAGE_DOWN_OP,
 504                           OCFS2_CONTROL_MESSAGE_OP_LEN))
 505                 ret = ocfs2_control_do_down_msg(file, &msg.u_down);
 506         else
 507                 ret = -EINVAL;
 508
 509 out:
 510         return ret ? ret : count;
 511 }
 512
 513 static ssize_t ocfs2_control_write(struct file *file,
 514                                    const char __user *buf,
 515                                    size_t count,
 516                                    loff_t *ppos)
 517 {
 518         ssize_t ret;
 519
 520         switch (ocfs2_control_get_handshake_state(file)) {
 521                 case OCFS2_CONTROL_HANDSHAKE_INVALID:
 522                         ret = -EINVAL;
 523                         break;
 524
 525                 case OCFS2_CONTROL_HANDSHAKE_READ:
 526                         ret = ocfs2_control_validate_protocol(file, buf,
 527                                                               count);
 528                         break;
 529
 530                 case OCFS2_CONTROL_HANDSHAKE_PROTOCOL:
 531                 case OCFS2_CONTROL_HANDSHAKE_VALID:
 532                         ret = ocfs2_control_message(file, buf, count);
 533                         break;
 534
 535                 default:
 536                         BUG();
 537                         ret = -EIO;
 538                         break;
 539         }
 540
 541         return ret;
 542 }
 543
 544 /*
 545  * This is a naive version.  If we ever have a new protocol, we'll expand
 546  * it.  Probably using seq_file.
 547  */
 548 static ssize_t ocfs2_control_read(struct file *file,
 549                                   char __user *buf,
 550                                   size_t count,
 551                                   loff_t *ppos)
 552 {
 553         ssize_t ret;
 554
 555         ret = simple_read_from_buffer(buf, count, ppos,
 556                         OCFS2_CONTROL_PROTO, OCFS2_CONTROL_PROTO_LEN);
 557
 558         /* Have we read the whole protocol list? */
 559         if (ret > 0 && *ppos >= OCFS2_CONTROL_PROTO_LEN)
 560                 ocfs2_control_set_handshake_state(file,
 561                                                   OCFS2_CONTROL_HANDSHAKE_READ);
 562
 563         return ret;
 564 }
 565
 566 static int ocfs2_control_release(struct inode *inode, struct file *file)
 567 {
 568         struct ocfs2_control_private *p = file->private_data;
 569
 570         mutex_lock(&ocfs2_control_lock);
 571
 572         if (ocfs2_control_get_handshake_state(file) !=
 573             OCFS2_CONTROL_HANDSHAKE_VALID)
 574                 goto out;
 575
 576         if (atomic_dec_and_test(&ocfs2_control_opened)) {
 577                 if (!list_empty(&ocfs2_live_connection_list)) {
 578                         /* XXX: Do bad things! */
 579                         printk(KERN_ERR
 580                                "ocfs2: Unexpected release of ocfs2_control!\n"
 581                                "       Loss of cluster connection requires "
 582                                "an emergency restart!\n");
 583                         emergency_restart();
 584                 }
 585                 /*
 586                  * Last valid close clears the node number and resets
 587                  * the locking protocol version
 588                  */
 589                 ocfs2_control_this_node = -1;
 590                 running_proto.pv_major = 0;
 591                 running_proto.pv_major = 0;
 592         }
 593
 594 out:
 595         list_del_init(&p->op_list);
 596         file->private_data = NULL;
 597
 598         mutex_unlock(&ocfs2_control_lock);
 599
 600         kfree(p);
 601
 602         return 0;
 603 }
 604
 605 static int ocfs2_control_open(struct inode *inode, struct file *file)
 606 {
 607         struct ocfs2_control_private *p;
 608
 609         p = kzalloc(sizeof(struct ocfs2_control_private), GFP_KERNEL);
 610         if (!p)
 611                 return -ENOMEM;
 612         p->op_this_node = -1;
 613
 614         lock_kernel();
 615         mutex_lock(&ocfs2_control_lock);
 616         file->private_data = p;
 617         list_add(&p->op_list, &ocfs2_control_private_list);
 618         mutex_unlock(&ocfs2_control_lock);
 619         unlock_kernel();
 620
 621         return 0;
 622 }
 623
 624 static const struct file_operations ocfs2_control_fops = {
 625         .open    = ocfs2_control_open,
 626         .release = ocfs2_control_release,
 627         .read    = ocfs2_control_read,
 628         .write   = ocfs2_control_write,
 629         .owner   = THIS_MODULE,
 630 };
 631
 632 static struct miscdevice ocfs2_control_device = {
 633         .minor          = MISC_DYNAMIC_MINOR,
 634         .name           = "ocfs2_control",
 635         .fops           = &ocfs2_control_fops,
 636 };
 637
 638 static int ocfs2_control_init(void)
 639 {
 640         int rc;
 641
 642         atomic_set(&ocfs2_control_opened, 0);
 643
 644         rc = misc_register(&ocfs2_control_device);
 645         if (rc)
 646                 printk(KERN_ERR
 647                        "ocfs2: Unable to register ocfs2_control device "
 648                        "(errno %d)\n",
 649                        -rc);
 650
 651         return rc;
 652 }
 653
 654 static void ocfs2_control_exit(void)
 655 {
 656         int rc;
 657
 658         rc = misc_deregister(&ocfs2_control_device);
 659         if (rc)
 660                 printk(KERN_ERR
 661                        "ocfs2: Unable to deregister ocfs2_control device "
 662                        "(errno %d)\n",
 663                        -rc);
 664 }
 665
 666 static struct dlm_lksb *fsdlm_astarg_to_lksb(void *astarg)
 667 {
 668         struct ocfs2_lock_res *res = astarg;
 669         return &res->l_lksb.lksb_fsdlm;
 670 }
 671
 672 static void fsdlm_lock_ast_wrapper(void *astarg)
 673 {
 674         struct dlm_lksb *lksb = fsdlm_astarg_to_lksb(astarg);
 675         int status = lksb->sb_status;
 676
 677         BUG_ON(ocfs2_user_plugin.sp_proto == NULL);
 678
 679         /*
 680          * For now we're punting on the issue of other non-standard errors
 681          * where we can't tell if the unlock_ast or lock_ast should be called.
 682          * The main "other error" that's possible is EINVAL which means the
 683          * function was called with invalid args, which shouldn't be possible
 684          * since the caller here is under our control.  Other non-standard
 685          * errors probably fall into the same category, or otherwise are fatal
 686          * which means we can't carry on anyway.
 687          */
 688
 689         if (status == -DLM_EUNLOCK || status == -DLM_ECANCEL)
 690                 ocfs2_user_plugin.sp_proto->lp_unlock_ast(astarg, 0);
 691         else
 692                 ocfs2_user_plugin.sp_proto->lp_lock_ast(astarg);
 693 }
 694
 695 static void fsdlm_blocking_ast_wrapper(void *astarg, int level)
 696 {
 697         BUG_ON(ocfs2_user_plugin.sp_proto == NULL);
 698
 699         ocfs2_user_plugin.sp_proto->lp_blocking_ast(astarg, level);
 700 }
 701
 702 static int user_dlm_lock(struct ocfs2_cluster_connection *conn,
 703                          int mode,
 704                          union ocfs2_dlm_lksb *lksb,
 705                          u32 flags,
 706                          void *name,
 707                          unsigned int namelen,
 708                          void *astarg)
 709 {
 710         int ret;
 711
 712         if (!lksb->lksb_fsdlm.sb_lvbptr)
 713                 lksb->lksb_fsdlm.sb_lvbptr = (char *)lksb +
 714                                              sizeof(struct dlm_lksb);
 715
 716         ret = dlm_lock(conn->cc_lockspace, mode, &lksb->lksb_fsdlm,
 717                        flags|DLM_LKF_NODLCKWT, name, namelen, 0,
 718                        fsdlm_lock_ast_wrapper, astarg,
 719                        fsdlm_blocking_ast_wrapper);
 720         return ret;
 721 }
 722
 723 static int user_dlm_unlock(struct ocfs2_cluster_connection *conn,
 724                            union ocfs2_dlm_lksb *lksb,
 725                            u32 flags,
 726                            void *astarg)
 727 {
 728         int ret;
 729
 730         ret = dlm_unlock(conn->cc_lockspace, lksb->lksb_fsdlm.sb_lkid,
 731                          flags, &lksb->lksb_fsdlm, astarg);
 732         return ret;
 733 }
 734
 735 static int user_dlm_lock_status(union ocfs2_dlm_lksb *lksb)
 736 {
 737         return lksb->lksb_fsdlm.sb_status;
 738 }
 739
 740 static void *user_dlm_lvb(union ocfs2_dlm_lksb *lksb)
 741 {
 742         return (void *)(lksb->lksb_fsdlm.sb_lvbptr);
 743 }
 744
 745 static void user_dlm_dump_lksb(union ocfs2_dlm_lksb *lksb)
 746 {
 747 }
 748
 749 /*
 750  * Compare a requested locking protocol version against the current one.
 751  *
 752  * If the major numbers are different, they are incompatible.
 753  * If the current minor is greater than the request, they are incompatible.
 754  * If the current minor is less than or equal to the request, they are
 755  * compatible, and the requester should run at the current minor version.
 756  */
 757 static int fs_protocol_compare(struct ocfs2_protocol_version *existing,
 758                                struct ocfs2_protocol_version *request)
 759 {
 760         if (existing->pv_major != request->pv_major)
 761                 return 1;
 762
 763         if (existing->pv_minor > request->pv_minor)
 764                 return 1;
 765
 766         if (existing->pv_minor < request->pv_minor)
 767                 request->pv_minor = existing->pv_minor;
 768
 769         return 0;
 770 }
 771
 772 static int user_cluster_connect(struct ocfs2_cluster_connection *conn)
 773 {
 774         dlm_lockspace_t *fsdlm;
 775         struct ocfs2_live_connection *control;
 776         int rc = 0;
 777
 778         BUG_ON(conn == NULL);
 779
 780         rc = ocfs2_live_connection_new(conn, &control);
 781         if (rc)
 782                 goto out;
 783
 784         /*
 785          * running_proto must have been set before we allowed any mounts
 786          * to proceed.
 787          */
 788         if (fs_protocol_compare(&running_proto, &conn->cc_version)) {
 789                 printk(KERN_ERR
 790                        "Unable to mount with fs locking protocol version "
 791                        "%u.%u because the userspace control daemon has "
 792                        "negotiated %u.%u\n",
 793                        conn->cc_version.pv_major, conn->cc_version.pv_minor,
 794                        running_proto.pv_major, running_proto.pv_minor);
 795                 rc = -EPROTO;
 796                 ocfs2_live_connection_drop(control);
 797                 goto out;
 798         }
 799
 800         rc = dlm_new_lockspace(conn->cc_name, strlen(conn->cc_name),
 801                                &fsdlm, DLM_LSFL_FS, DLM_LVB_LEN);
 802         if (rc) {
 803                 ocfs2_live_connection_drop(control);
 804                 goto out;
 805         }
 806
 807         conn->cc_private = control;
 808         conn->cc_lockspace = fsdlm;
 809 out:
 810         return rc;
 811 }
 812
 813 static int user_cluster_disconnect(struct ocfs2_cluster_connection *conn)
 814 {
 815         dlm_release_lockspace(conn->cc_lockspace, 2);
 816         conn->cc_lockspace = NULL;
 817         ocfs2_live_connection_drop(conn->cc_private);
 818         conn->cc_private = NULL;
 819         return 0;
 820 }
 821
 822 static int user_cluster_this_node(unsigned int *this_node)
 823 {
 824         int rc;
 825
 826         rc = ocfs2_control_get_this_node();
 827         if (rc < 0)
 828                 return rc;
 829
 830         *this_node = rc;
 831         return 0;
 832 }
 833
 834 static struct ocfs2_stack_operations ocfs2_user_plugin_ops = {
 835         .connect        = user_cluster_connect,
 836         .disconnect     = user_cluster_disconnect,
 837         .this_node      = user_cluster_this_node,
 838         .dlm_lock       = user_dlm_lock,
 839         .dlm_unlock     = user_dlm_unlock,
 840         .lock_status    = user_dlm_lock_status,
 841         .lock_lvb       = user_dlm_lvb,
 842         .dump_lksb      = user_dlm_dump_lksb,
 843 };
 844
 845 static struct ocfs2_stack_plugin ocfs2_user_plugin = {
 846         .sp_name        = "user",
 847         .sp_ops         = &ocfs2_user_plugin_ops,
 848         .sp_owner       = THIS_MODULE,
 849 };
 850
 851
 852 static int __init ocfs2_user_plugin_init(void)
 853 {
 854         int rc;
 855
 856         rc = ocfs2_control_init();
 857         if (!rc) {
 858                 rc = ocfs2_stack_glue_register(&ocfs2_user_plugin);
 859                 if (rc)
 860                         ocfs2_control_exit();
 861         }
 862
 863         return rc;
 864 }
 865
 866 static void __exit ocfs2_user_plugin_exit(void)
 867 {
 868         ocfs2_stack_glue_unregister(&ocfs2_user_plugin);
 869         ocfs2_control_exit();
 870 }
 871
 872 MODULE_AUTHOR("Oracle");
 873 MODULE_DESCRIPTION("ocfs2 driver for userspace cluster stacks");
 874 MODULE_LICENSE("GPL");
 875 module_init(ocfs2_user_plugin_init);
 876 module_exit(ocfs2_user_plugin_exit);