SAFE public projects git trees. - safe/jmp/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 #include <linux/dlm_plock.h>
  32
  33 /*
  34  * The control protocol starts with a handshake.  Until the handshake
  35  * is complete, the control device will fail all write(2)s.
  36  *
  37  * The handshake is simple.  First, the client reads until EOF.  Each line
  38  * of output is a supported protocol tag.  All protocol tags are a single
  39  * character followed by a two hex digit version number.  Currently the
  40  * only things supported is T01, for "Text-base version 0x01".  Next, the
  41  * client writes the version they would like to use, including the newline.
  42  * Thus, the protocol tag is 'T01\n'.  If the version tag written is
  43  * unknown, -EINVAL is returned.  Once the negotiation is complete, the
  44  * client can start sending messages.
  45  *
  46  * The T01 protocol has three messages.  First is the "SETN" message.
  47  * It has the following syntax:
  48  *
  49  *  SETN<space><8-char-hex-nodenum><newline>
  50  *
  51  * This is 14 characters.
  52  *
  53  * The "SETN" message must be the first message following the protocol.
  54  * It tells ocfs2_control the local node number.
  55  *
  56  * Next comes the "SETV" message.  It has the following syntax:
  57  *
  58  *  SETV<space><2-char-hex-major><space><2-char-hex-minor><newline>
  59  *
  60  * This is 11 characters.
  61  *
  62  * The "SETV" message sets the filesystem locking protocol version as
  63  * negotiated by the client.  The client negotiates based on the maximum
  64  * version advertised in /sys/fs/ocfs2/max_locking_protocol.  The major
  65  * number from the "SETV" message must match
  66  * ocfs2_user_plugin.sp_proto->lp_max_version.pv_major, and the minor number
  67  * must be less than or equal to ...->lp_max_version.pv_minor.
  68  *
  69  * Once this information has been set, mounts will be allowed.  From this
  70  * point on, the "DOWN" message can be sent for node down notification.
  71  * It has the following syntax:
  72  *
  73  *  DOWN<space><32-char-cap-hex-uuid><space><8-char-hex-nodenum><newline>
  74  *
  75  * eg:
  76  *
  77  *  DOWN 632A924FDD844190BDA93C0DF6B94899 00000001\n
  78  *
  79  * This is 47 characters.
  80  */
  81
  82 /*
  83  * Whether or not the client has done the handshake.
  84  * For now, we have just one protocol version.
  85  */
  86 #define OCFS2_CONTROL_PROTO                     "T01\n"
  87 #define OCFS2_CONTROL_PROTO_LEN                 4
  88
  89 /* Handshake states */
  90 #define OCFS2_CONTROL_HANDSHAKE_INVALID         (0)
  91 #define OCFS2_CONTROL_HANDSHAKE_READ            (1)
  92 #define OCFS2_CONTROL_HANDSHAKE_PROTOCOL        (2)
  93 #define OCFS2_CONTROL_HANDSHAKE_VALID           (3)
  94
  95 /* Messages */
  96 #define OCFS2_CONTROL_MESSAGE_OP_LEN            4
  97 #define OCFS2_CONTROL_MESSAGE_SETNODE_OP        "SETN"
  98 #define OCFS2_CONTROL_MESSAGE_SETNODE_TOTAL_LEN 14
  99 #define OCFS2_CONTROL_MESSAGE_SETVERSION_OP     "SETV"
 100 #define OCFS2_CONTROL_MESSAGE_SETVERSION_TOTAL_LEN      11
 101 #define OCFS2_CONTROL_MESSAGE_DOWN_OP           "DOWN"
 102 #define OCFS2_CONTROL_MESSAGE_DOWN_TOTAL_LEN    47
 103 #define OCFS2_TEXT_UUID_LEN                     32
 104 #define OCFS2_CONTROL_MESSAGE_VERNUM_LEN        2
 105 #define OCFS2_CONTROL_MESSAGE_NODENUM_LEN       8
 106
 107 /*
 108  * ocfs2_live_connection is refcounted because the filesystem and
 109  * miscdevice sides can detach in different order.  Let's just be safe.
 110  */
 111 struct ocfs2_live_connection {
 112         struct list_head                oc_list;
 113         struct ocfs2_cluster_connection *oc_conn;
 114 };
 115
 116 struct ocfs2_control_private {
 117         struct list_head op_list;
 118         int op_state;
 119         int op_this_node;
 120         struct ocfs2_protocol_version op_proto;
 121 };
 122
 123 /* SETN<space><8-char-hex-nodenum><newline> */
 124 struct ocfs2_control_message_setn {
 125         char    tag[OCFS2_CONTROL_MESSAGE_OP_LEN];
 126         char    space;
 127         char    nodestr[OCFS2_CONTROL_MESSAGE_NODENUM_LEN];
 128         char    newline;
 129 };
 130
 131 /* SETV<space><2-char-hex-major><space><2-char-hex-minor><newline> */
 132 struct ocfs2_control_message_setv {
 133         char    tag[OCFS2_CONTROL_MESSAGE_OP_LEN];
 134         char    space1;
 135         char    major[OCFS2_CONTROL_MESSAGE_VERNUM_LEN];
 136         char    space2;
 137         char    minor[OCFS2_CONTROL_MESSAGE_VERNUM_LEN];
 138         char    newline;
 139 };
 140
 141 /* DOWN<space><32-char-cap-hex-uuid><space><8-char-hex-nodenum><newline> */
 142 struct ocfs2_control_message_down {
 143         char    tag[OCFS2_CONTROL_MESSAGE_OP_LEN];
 144         char    space1;
 145         char    uuid[OCFS2_TEXT_UUID_LEN];
 146         char    space2;
 147         char    nodestr[OCFS2_CONTROL_MESSAGE_NODENUM_LEN];
 148         char    newline;
 149 };
 150
 151 union ocfs2_control_message {
 152         char                                    tag[OCFS2_CONTROL_MESSAGE_OP_LEN];
 153         struct ocfs2_control_message_setn       u_setn;
 154         struct ocfs2_control_message_setv       u_setv;
 155         struct ocfs2_control_message_down       u_down;
 156 };
 157
 158 static struct ocfs2_stack_plugin ocfs2_user_plugin;
 159
 160 static atomic_t ocfs2_control_opened;
 161 static int ocfs2_control_this_node = -1;
 162 static struct ocfs2_protocol_version running_proto;
 163
 164 static LIST_HEAD(ocfs2_live_connection_list);
 165 static LIST_HEAD(ocfs2_control_private_list);
 166 static DEFINE_MUTEX(ocfs2_control_lock);
 167
 168 static inline void ocfs2_control_set_handshake_state(struct file *file,
 169                                                      int state)
 170 {
 171         struct ocfs2_control_private *p = file->private_data;
 172         p->op_state = state;
 173 }
 174
 175 static inline int ocfs2_control_get_handshake_state(struct file *file)
 176 {
 177         struct ocfs2_control_private *p = file->private_data;
 178         return p->op_state;
 179 }
 180
 181 static struct ocfs2_live_connection *ocfs2_connection_find(const char *name)
 182 {
 183         size_t len = strlen(name);
 184         struct ocfs2_live_connection *c;
 185
 186         BUG_ON(!mutex_is_locked(&ocfs2_control_lock));
 187
 188         list_for_each_entry(c, &ocfs2_live_connection_list, oc_list) {
 189                 if ((c->oc_conn->cc_namelen == len) &&
 190                     !strncmp(c->oc_conn->cc_name, name, len))
 191                         return c;
 192         }
 193
 194         return c;
 195 }
 196
 197 /*
 198  * ocfs2_live_connection structures are created underneath the ocfs2
 199  * mount path.  Since the VFS prevents multiple calls to
 200  * fill_super(), we can't get dupes here.
 201  */
 202 static int ocfs2_live_connection_new(struct ocfs2_cluster_connection *conn,
 203                                      struct ocfs2_live_connection **c_ret)
 204 {
 205         int rc = 0;
 206         struct ocfs2_live_connection *c;
 207
 208         c = kzalloc(sizeof(struct ocfs2_live_connection), GFP_KERNEL);
 209         if (!c)
 210                 return -ENOMEM;
 211
 212         mutex_lock(&ocfs2_control_lock);
 213         c->oc_conn = conn;
 214
 215         if (atomic_read(&ocfs2_control_opened))
 216                 list_add(&c->oc_list, &ocfs2_live_connection_list);
 217         else {
 218                 printk(KERN_ERR
 219                        "ocfs2: Userspace control daemon is not present\n");
 220                 rc = -ESRCH;
 221         }
 222
 223         mutex_unlock(&ocfs2_control_lock);
 224
 225         if (!rc)
 226                 *c_ret = c;
 227         else
 228                 kfree(c);
 229
 230         return rc;
 231 }
 232
 233 /*
 234  * This function disconnects the cluster connection from ocfs2_control.
 235  * Afterwards, userspace can't affect the cluster connection.
 236  */
 237 static void ocfs2_live_connection_drop(struct ocfs2_live_connection *c)
 238 {
 239         mutex_lock(&ocfs2_control_lock);
 240         list_del_init(&c->oc_list);
 241         c->oc_conn = NULL;
 242         mutex_unlock(&ocfs2_control_lock);
 243
 244         kfree(c);
 245 }
 246
 247 static int ocfs2_control_cfu(void *target, size_t target_len,
 248                              const char __user *buf, size_t count)
 249 {
 250         /* The T01 expects write(2) calls to have exactly one command */
 251         if ((count != target_len) ||
 252             (count > sizeof(union ocfs2_control_message)))
 253                 return -EINVAL;
 254
 255         if (copy_from_user(target, buf, target_len))
 256                 return -EFAULT;
 257
 258         return 0;
 259 }
 260
 261 static ssize_t ocfs2_control_validate_protocol(struct file *file,
 262                                                const char __user *buf,
 263                                                size_t count)
 264 {
 265         ssize_t ret;
 266         char kbuf[OCFS2_CONTROL_PROTO_LEN];
 267
 268         ret = ocfs2_control_cfu(kbuf, OCFS2_CONTROL_PROTO_LEN,
 269                                 buf, count);
 270         if (ret)
 271                 return ret;
 272
 273         if (strncmp(kbuf, OCFS2_CONTROL_PROTO, OCFS2_CONTROL_PROTO_LEN))
 274                 return -EINVAL;
 275
 276         ocfs2_control_set_handshake_state(file,
 277                                           OCFS2_CONTROL_HANDSHAKE_PROTOCOL);
 278
 279         return count;
 280 }
 281
 282 static void ocfs2_control_send_down(const char *uuid,
 283                                     int nodenum)
 284 {
 285         struct ocfs2_live_connection *c;
 286
 287         mutex_lock(&ocfs2_control_lock);
 288
 289         c = ocfs2_connection_find(uuid);
 290         if (c) {
 291                 BUG_ON(c->oc_conn == NULL);
 292                 c->oc_conn->cc_recovery_handler(nodenum,
 293                                                 c->oc_conn->cc_recovery_data);
 294         }
 295
 296         mutex_unlock(&ocfs2_control_lock);
 297 }
 298
 299 /*
 300  * Called whenever configuration elements are sent to /dev/ocfs2_control.
 301  * If all configuration elements are present, try to set the global
 302  * values.  If there is a problem, return an error.  Skip any missing
 303  * elements, and only bump ocfs2_control_opened when we have all elements
 304  * and are successful.
 305  */
 306 static int ocfs2_control_install_private(struct file *file)
 307 {
 308         int rc = 0;
 309         int set_p = 1;
 310         struct ocfs2_control_private *p = file->private_data;
 311
 312         BUG_ON(p->op_state != OCFS2_CONTROL_HANDSHAKE_PROTOCOL);
 313
 314         mutex_lock(&ocfs2_control_lock);
 315
 316         if (p->op_this_node < 0) {
 317                 set_p = 0;
 318         } else if ((ocfs2_control_this_node >= 0) &&
 319                    (ocfs2_control_this_node != p->op_this_node)) {
 320                 rc = -EINVAL;
 321                 goto out_unlock;
 322         }
 323
 324         if (!p->op_proto.pv_major) {
 325                 set_p = 0;
 326         } else if (!list_empty(&ocfs2_live_connection_list) &&
 327                    ((running_proto.pv_major != p->op_proto.pv_major) ||
 328                     (running_proto.pv_minor != p->op_proto.pv_minor))) {
 329                 rc = -EINVAL;
 330                 goto out_unlock;
 331         }
 332
 333         if (set_p) {
 334                 ocfs2_control_this_node = p->op_this_node;
 335                 running_proto.pv_major = p->op_proto.pv_major;
 336                 running_proto.pv_minor = p->op_proto.pv_minor;
 337         }
 338
 339 out_unlock:
 340         mutex_unlock(&ocfs2_control_lock);
 341
 342         if (!rc && set_p) {
 343                 /* We set the global values successfully */
 344                 atomic_inc(&ocfs2_control_opened);
 345                 ocfs2_control_set_handshake_state(file,
 346                                         OCFS2_CONTROL_HANDSHAKE_VALID);
 347         }
 348
 349         return rc;
 350 }
 351
 352 static int ocfs2_control_get_this_node(void)
 353 {
 354         int rc;
 355
 356         mutex_lock(&ocfs2_control_lock);
 357         if (ocfs2_control_this_node < 0)
 358                 rc = -EINVAL;
 359         else
 360                 rc = ocfs2_control_this_node;
 361         mutex_unlock(&ocfs2_control_lock);
 362
 363         return rc;
 364 }
 365
 366 static int ocfs2_control_do_setnode_msg(struct file *file,
 367                                         struct ocfs2_control_message_setn *msg)
 368 {
 369         long nodenum;
 370         char *ptr = NULL;
 371         struct ocfs2_control_private *p = file->private_data;
 372
 373         if (ocfs2_control_get_handshake_state(file) !=
 374             OCFS2_CONTROL_HANDSHAKE_PROTOCOL)
 375                 return -EINVAL;
 376
 377         if (strncmp(msg->tag, OCFS2_CONTROL_MESSAGE_SETNODE_OP,
 378                     OCFS2_CONTROL_MESSAGE_OP_LEN))
 379                 return -EINVAL;
 380
 381         if ((msg->space != ' ') || (msg->newline != '\n'))
 382                 return -EINVAL;
 383         msg->space = msg->newline = '\0';
 384
 385         nodenum = simple_strtol(msg->nodestr, &ptr, 16);
 386         if (!ptr || *ptr)
 387                 return -EINVAL;
 388
 389         if ((nodenum == LONG_MIN) || (nodenum == LONG_MAX) ||
 390             (nodenum > INT_MAX) || (nodenum < 0))
 391                 return -ERANGE;
 392         p->op_this_node = nodenum;
 393
 394         return ocfs2_control_install_private(file);
 395 }
 396
 397 static int ocfs2_control_do_setversion_msg(struct file *file,
 398                                            struct ocfs2_control_message_setv *msg)
 399  {
 400         long major, minor;
 401         char *ptr = NULL;
 402         struct ocfs2_control_private *p = file->private_data;
 403         struct ocfs2_protocol_version *max =
 404                 &ocfs2_user_plugin.sp_proto->lp_max_version;
 405
 406         if (ocfs2_control_get_handshake_state(file) !=
 407             OCFS2_CONTROL_HANDSHAKE_PROTOCOL)
 408                 return -EINVAL;
 409
 410         if (strncmp(msg->tag, OCFS2_CONTROL_MESSAGE_SETVERSION_OP,
 411                     OCFS2_CONTROL_MESSAGE_OP_LEN))
 412                 return -EINVAL;
 413
 414         if ((msg->space1 != ' ') || (msg->space2 != ' ') ||
 415             (msg->newline != '\n'))
 416                 return -EINVAL;
 417         msg->space1 = msg->space2 = msg->newline = '\0';
 418
 419         major = simple_strtol(msg->major, &ptr, 16);
 420         if (!ptr || *ptr)
 421                 return -EINVAL;
 422         minor = simple_strtol(msg->minor, &ptr, 16);
 423         if (!ptr || *ptr)
 424                 return -EINVAL;
 425
 426         /*
 427          * The major must be between 1 and 255, inclusive.  The minor
 428          * must be between 0 and 255, inclusive.  The version passed in
 429          * must be within the maximum version supported by the filesystem.
 430          */
 431         if ((major == LONG_MIN) || (major == LONG_MAX) ||
 432             (major > (u8)-1) || (major < 1))
 433                 return -ERANGE;
 434         if ((minor == LONG_MIN) || (minor == LONG_MAX) ||
 435             (minor > (u8)-1) || (minor < 0))
 436                 return -ERANGE;
 437         if ((major != max->pv_major) ||
 438             (minor > max->pv_minor))
 439                 return -EINVAL;
 440
 441         p->op_proto.pv_major = major;
 442         p->op_proto.pv_minor = minor;
 443
 444         return ocfs2_control_install_private(file);
 445 }
 446
 447 static int ocfs2_control_do_down_msg(struct file *file,
 448                                      struct ocfs2_control_message_down *msg)
 449 {
 450         long nodenum;
 451         char *p = NULL;
 452
 453         if (ocfs2_control_get_handshake_state(file) !=
 454             OCFS2_CONTROL_HANDSHAKE_VALID)
 455                 return -EINVAL;
 456
 457         if (strncmp(msg->tag, OCFS2_CONTROL_MESSAGE_DOWN_OP,
 458                     OCFS2_CONTROL_MESSAGE_OP_LEN))
 459                 return -EINVAL;
 460
 461         if ((msg->space1 != ' ') || (msg->space2 != ' ') ||
 462             (msg->newline != '\n'))
 463                 return -EINVAL;
 464         msg->space1 = msg->space2 = msg->newline = '\0';
 465
 466         nodenum = simple_strtol(msg->nodestr, &p, 16);
 467         if (!p || *p)
 468                 return -EINVAL;
 469
 470         if ((nodenum == LONG_MIN) || (nodenum == LONG_MAX) ||
 471             (nodenum > INT_MAX) || (nodenum < 0))
 472                 return -ERANGE;
 473
 474         ocfs2_control_send_down(msg->uuid, nodenum);
 475
 476         return 0;
 477 }
 478
 479 static ssize_t ocfs2_control_message(struct file *file,
 480                                      const char __user *buf,
 481                                      size_t count)
 482 {
 483         ssize_t ret;
 484         union ocfs2_control_message msg;
 485
 486         /* Try to catch padding issues */
 487         WARN_ON(offsetof(struct ocfs2_control_message_down, uuid) !=
 488                 (sizeof(msg.u_down.tag) + sizeof(msg.u_down.space1)));
 489
 490         memset(&msg, 0, sizeof(union ocfs2_control_message));
 491         ret = ocfs2_control_cfu(&msg, count, buf, count);
 492         if (ret)
 493                 goto out;
 494
 495         if ((count == OCFS2_CONTROL_MESSAGE_SETNODE_TOTAL_LEN) &&
 496             !strncmp(msg.tag, OCFS2_CONTROL_MESSAGE_SETNODE_OP,
 497                      OCFS2_CONTROL_MESSAGE_OP_LEN))
 498                 ret = ocfs2_control_do_setnode_msg(file, &msg.u_setn);
 499         else if ((count == OCFS2_CONTROL_MESSAGE_SETVERSION_TOTAL_LEN) &&
 500                  !strncmp(msg.tag, OCFS2_CONTROL_MESSAGE_SETVERSION_OP,
 501                           OCFS2_CONTROL_MESSAGE_OP_LEN))
 502                 ret = ocfs2_control_do_setversion_msg(file, &msg.u_setv);
 503         else if ((count == OCFS2_CONTROL_MESSAGE_DOWN_TOTAL_LEN) &&
 504                  !strncmp(msg.tag, OCFS2_CONTROL_MESSAGE_DOWN_OP,
 505                           OCFS2_CONTROL_MESSAGE_OP_LEN))
 506                 ret = ocfs2_control_do_down_msg(file, &msg.u_down);
 507         else
 508                 ret = -EINVAL;
 509
 510 out:
 511         return ret ? ret : count;
 512 }
 513
 514 static ssize_t ocfs2_control_write(struct file *file,
 515                                    const char __user *buf,
 516                                    size_t count,
 517                                    loff_t *ppos)
 518 {
 519         ssize_t ret;
 520
 521         switch (ocfs2_control_get_handshake_state(file)) {
 522                 case OCFS2_CONTROL_HANDSHAKE_INVALID:
 523                         ret = -EINVAL;
 524                         break;
 525
 526                 case OCFS2_CONTROL_HANDSHAKE_READ:
 527                         ret = ocfs2_control_validate_protocol(file, buf,
 528                                                               count);
 529                         break;
 530
 531                 case OCFS2_CONTROL_HANDSHAKE_PROTOCOL:
 532                 case OCFS2_CONTROL_HANDSHAKE_VALID:
 533                         ret = ocfs2_control_message(file, buf, count);
 534                         break;
 535
 536                 default:
 537                         BUG();
 538                         ret = -EIO;
 539                         break;
 540         }
 541
 542         return ret;
 543 }
 544
 545 /*
 546  * This is a naive version.  If we ever have a new protocol, we'll expand
 547  * it.  Probably using seq_file.
 548  */
 549 static ssize_t ocfs2_control_read(struct file *file,
 550                                   char __user *buf,
 551                                   size_t count,
 552                                   loff_t *ppos)
 553 {
 554         ssize_t ret;
 555
 556         ret = simple_read_from_buffer(buf, count, ppos,
 557                         OCFS2_CONTROL_PROTO, OCFS2_CONTROL_PROTO_LEN);
 558
 559         /* Have we read the whole protocol list? */
 560         if (ret > 0 && *ppos >= OCFS2_CONTROL_PROTO_LEN)
 561                 ocfs2_control_set_handshake_state(file,
 562                                                   OCFS2_CONTROL_HANDSHAKE_READ);
 563
 564         return ret;
 565 }
 566
 567 static int ocfs2_control_release(struct inode *inode, struct file *file)
 568 {
 569         struct ocfs2_control_private *p = file->private_data;
 570
 571         mutex_lock(&ocfs2_control_lock);
 572
 573         if (ocfs2_control_get_handshake_state(file) !=
 574             OCFS2_CONTROL_HANDSHAKE_VALID)
 575                 goto out;
 576
 577         if (atomic_dec_and_test(&ocfs2_control_opened)) {
 578                 if (!list_empty(&ocfs2_live_connection_list)) {
 579                         /* XXX: Do bad things! */
 580                         printk(KERN_ERR
 581                                "ocfs2: Unexpected release of ocfs2_control!\n"
 582                                "       Loss of cluster connection requires "
 583                                "an emergency restart!\n");
 584                         emergency_restart();
 585                 }
 586                 /*
 587                  * Last valid close clears the node number and resets
 588                  * the locking protocol version
 589                  */
 590                 ocfs2_control_this_node = -1;
 591                 running_proto.pv_major = 0;
 592                 running_proto.pv_major = 0;
 593         }
 594
 595 out:
 596         list_del_init(&p->op_list);
 597         file->private_data = NULL;
 598
 599         mutex_unlock(&ocfs2_control_lock);
 600
 601         kfree(p);
 602
 603         return 0;
 604 }
 605
 606 static int ocfs2_control_open(struct inode *inode, struct file *file)
 607 {
 608         struct ocfs2_control_private *p;
 609
 610         p = kzalloc(sizeof(struct ocfs2_control_private), GFP_KERNEL);
 611         if (!p)
 612                 return -ENOMEM;
 613         p->op_this_node = -1;
 614
 615         lock_kernel();
 616         mutex_lock(&ocfs2_control_lock);
 617         file->private_data = p;
 618         list_add(&p->op_list, &ocfs2_control_private_list);
 619         mutex_unlock(&ocfs2_control_lock);
 620         unlock_kernel();
 621
 622         return 0;
 623 }
 624
 625 static const struct file_operations ocfs2_control_fops = {
 626         .open    = ocfs2_control_open,
 627         .release = ocfs2_control_release,
 628         .read    = ocfs2_control_read,
 629         .write   = ocfs2_control_write,
 630         .owner   = THIS_MODULE,
 631 };
 632
 633 static struct miscdevice ocfs2_control_device = {
 634         .minor          = MISC_DYNAMIC_MINOR,
 635         .name           = "ocfs2_control",
 636         .fops           = &ocfs2_control_fops,
 637 };
 638
 639 static int ocfs2_control_init(void)
 640 {
 641         int rc;
 642
 643         atomic_set(&ocfs2_control_opened, 0);
 644
 645         rc = misc_register(&ocfs2_control_device);
 646         if (rc)
 647                 printk(KERN_ERR
 648                        "ocfs2: Unable to register ocfs2_control device "
 649                        "(errno %d)\n",
 650                        -rc);
 651
 652         return rc;
 653 }
 654
 655 static void ocfs2_control_exit(void)
 656 {
 657         int rc;
 658
 659         rc = misc_deregister(&ocfs2_control_device);
 660         if (rc)
 661                 printk(KERN_ERR
 662                        "ocfs2: Unable to deregister ocfs2_control device "
 663                        "(errno %d)\n",
 664                        -rc);
 665 }
 666
 667 static struct dlm_lksb *fsdlm_astarg_to_lksb(void *astarg)
 668 {
 669         struct ocfs2_lock_res *res = astarg;
 670         return &res->l_lksb.lksb_fsdlm;
 671 }
 672
 673 static void fsdlm_lock_ast_wrapper(void *astarg)
 674 {
 675         struct dlm_lksb *lksb = fsdlm_astarg_to_lksb(astarg);
 676         int status = lksb->sb_status;
 677
 678         BUG_ON(ocfs2_user_plugin.sp_proto == NULL);
 679
 680         /*
 681          * For now we're punting on the issue of other non-standard errors
 682          * where we can't tell if the unlock_ast or lock_ast should be called.
 683          * The main "other error" that's possible is EINVAL which means the
 684          * function was called with invalid args, which shouldn't be possible
 685          * since the caller here is under our control.  Other non-standard
 686          * errors probably fall into the same category, or otherwise are fatal
 687          * which means we can't carry on anyway.
 688          */
 689
 690         if (status == -DLM_EUNLOCK || status == -DLM_ECANCEL)
 691                 ocfs2_user_plugin.sp_proto->lp_unlock_ast(astarg, 0);
 692         else
 693                 ocfs2_user_plugin.sp_proto->lp_lock_ast(astarg);
 694 }
 695
 696 static void fsdlm_blocking_ast_wrapper(void *astarg, int level)
 697 {
 698         BUG_ON(ocfs2_user_plugin.sp_proto == NULL);
 699
 700         ocfs2_user_plugin.sp_proto->lp_blocking_ast(astarg, level);
 701 }
 702
 703 static int user_dlm_lock(struct ocfs2_cluster_connection *conn,
 704                          int mode,
 705                          union ocfs2_dlm_lksb *lksb,
 706                          u32 flags,
 707                          void *name,
 708                          unsigned int namelen,
 709                          void *astarg)
 710 {
 711         int ret;
 712
 713         if (!lksb->lksb_fsdlm.sb_lvbptr)
 714                 lksb->lksb_fsdlm.sb_lvbptr = (char *)lksb +
 715                                              sizeof(struct dlm_lksb);
 716
 717         ret = dlm_lock(conn->cc_lockspace, mode, &lksb->lksb_fsdlm,
 718                        flags|DLM_LKF_NODLCKWT, name, namelen, 0,
 719                        fsdlm_lock_ast_wrapper, astarg,
 720                        fsdlm_blocking_ast_wrapper);
 721         return ret;
 722 }
 723
 724 static int user_dlm_unlock(struct ocfs2_cluster_connection *conn,
 725                            union ocfs2_dlm_lksb *lksb,
 726                            u32 flags,
 727                            void *astarg)
 728 {
 729         int ret;
 730
 731         ret = dlm_unlock(conn->cc_lockspace, lksb->lksb_fsdlm.sb_lkid,
 732                          flags, &lksb->lksb_fsdlm, astarg);
 733         return ret;
 734 }
 735
 736 static int user_dlm_lock_status(union ocfs2_dlm_lksb *lksb)
 737 {
 738         return lksb->lksb_fsdlm.sb_status;
 739 }
 740
 741 static int user_dlm_lvb_valid(union ocfs2_dlm_lksb *lksb)
 742 {
 743         int invalid = lksb->lksb_fsdlm.sb_flags & DLM_SBF_VALNOTVALID;
 744
 745         return !invalid;
 746 }
 747
 748 static void *user_dlm_lvb(union ocfs2_dlm_lksb *lksb)
 749 {
 750         if (!lksb->lksb_fsdlm.sb_lvbptr)
 751                 lksb->lksb_fsdlm.sb_lvbptr = (char *)lksb +
 752                                              sizeof(struct dlm_lksb);
 753         return (void *)(lksb->lksb_fsdlm.sb_lvbptr);
 754 }
 755
 756 static void user_dlm_dump_lksb(union ocfs2_dlm_lksb *lksb)
 757 {
 758 }
 759
 760 static int user_plock(struct ocfs2_cluster_connection *conn,
 761                       u64 ino,
 762                       struct file *file,
 763                       int cmd,
 764                       struct file_lock *fl)
 765 {
 766         /*
 767          * This more or less just demuxes the plock request into any
 768          * one of three dlm calls.
 769          *
 770          * Internally, fs/dlm will pass these to a misc device, which
 771          * a userspace daemon will read and write to.
 772          *
 773          * For now, cancel requests (which happen internally only),
 774          * are turned into unlocks. Most of this function taken from
 775          * gfs2_lock.
 776          */
 777
 778         if (cmd == F_CANCELLK) {
 779                 cmd = F_SETLK;
 780                 fl->fl_type = F_UNLCK;
 781         }
 782
 783         if (IS_GETLK(cmd))
 784                 return dlm_posix_get(conn->cc_lockspace, ino, file, fl);
 785         else if (fl->fl_type == F_UNLCK)
 786                 return dlm_posix_unlock(conn->cc_lockspace, ino, file, fl);
 787         else
 788                 return dlm_posix_lock(conn->cc_lockspace, ino, file, cmd, fl);
 789 }
 790
 791 /*
 792  * Compare a requested locking protocol version against the current one.
 793  *
 794  * If the major numbers are different, they are incompatible.
 795  * If the current minor is greater than the request, they are incompatible.
 796  * If the current minor is less than or equal to the request, they are
 797  * compatible, and the requester should run at the current minor version.
 798  */
 799 static int fs_protocol_compare(struct ocfs2_protocol_version *existing,
 800                                struct ocfs2_protocol_version *request)
 801 {
 802         if (existing->pv_major != request->pv_major)
 803                 return 1;
 804
 805         if (existing->pv_minor > request->pv_minor)
 806                 return 1;
 807
 808         if (existing->pv_minor < request->pv_minor)
 809                 request->pv_minor = existing->pv_minor;
 810
 811         return 0;
 812 }
 813
 814 static int user_cluster_connect(struct ocfs2_cluster_connection *conn)
 815 {
 816         dlm_lockspace_t *fsdlm;
 817         struct ocfs2_live_connection *uninitialized_var(control);
 818         int rc = 0;
 819
 820         BUG_ON(conn == NULL);
 821
 822         rc = ocfs2_live_connection_new(conn, &control);
 823         if (rc)
 824                 goto out;
 825
 826         /*
 827          * running_proto must have been set before we allowed any mounts
 828          * to proceed.
 829          */
 830         if (fs_protocol_compare(&running_proto, &conn->cc_version)) {
 831                 printk(KERN_ERR
 832                        "Unable to mount with fs locking protocol version "
 833                        "%u.%u because the userspace control daemon has "
 834                        "negotiated %u.%u\n",
 835                        conn->cc_version.pv_major, conn->cc_version.pv_minor,
 836                        running_proto.pv_major, running_proto.pv_minor);
 837                 rc = -EPROTO;
 838                 ocfs2_live_connection_drop(control);
 839                 goto out;
 840         }
 841
 842         rc = dlm_new_lockspace(conn->cc_name, strlen(conn->cc_name),
 843                                &fsdlm, DLM_LSFL_FS, DLM_LVB_LEN);
 844         if (rc) {
 845                 ocfs2_live_connection_drop(control);
 846                 goto out;
 847         }
 848
 849         conn->cc_private = control;
 850         conn->cc_lockspace = fsdlm;
 851 out:
 852         return rc;
 853 }
 854
 855 static int user_cluster_disconnect(struct ocfs2_cluster_connection *conn)
 856 {
 857         dlm_release_lockspace(conn->cc_lockspace, 2);
 858         conn->cc_lockspace = NULL;
 859         ocfs2_live_connection_drop(conn->cc_private);
 860         conn->cc_private = NULL;
 861         return 0;
 862 }
 863
 864 static int user_cluster_this_node(unsigned int *this_node)
 865 {
 866         int rc;
 867
 868         rc = ocfs2_control_get_this_node();
 869         if (rc < 0)
 870                 return rc;
 871
 872         *this_node = rc;
 873         return 0;
 874 }
 875
 876 static struct ocfs2_stack_operations ocfs2_user_plugin_ops = {
 877         .connect        = user_cluster_connect,
 878         .disconnect     = user_cluster_disconnect,
 879         .this_node      = user_cluster_this_node,
 880         .dlm_lock       = user_dlm_lock,
 881         .dlm_unlock     = user_dlm_unlock,
 882         .lock_status    = user_dlm_lock_status,
 883         .lvb_valid      = user_dlm_lvb_valid,
 884         .lock_lvb       = user_dlm_lvb,
 885         .plock          = user_plock,
 886         .dump_lksb      = user_dlm_dump_lksb,
 887 };
 888
 889 static struct ocfs2_stack_plugin ocfs2_user_plugin = {
 890         .sp_name        = "user",
 891         .sp_ops         = &ocfs2_user_plugin_ops,
 892         .sp_owner       = THIS_MODULE,
 893 };
 894
 895
 896 static int __init ocfs2_user_plugin_init(void)
 897 {
 898         int rc;
 899
 900         rc = ocfs2_control_init();
 901         if (!rc) {
 902                 rc = ocfs2_stack_glue_register(&ocfs2_user_plugin);
 903                 if (rc)
 904                         ocfs2_control_exit();
 905         }
 906
 907         return rc;
 908 }
 909
 910 static void __exit ocfs2_user_plugin_exit(void)
 911 {
 912         ocfs2_stack_glue_unregister(&ocfs2_user_plugin);
 913         ocfs2_control_exit();
 914 }
 915
 916 MODULE_AUTHOR("Oracle");
 917 MODULE_DESCRIPTION("ocfs2 driver for userspace cluster stacks");
 918 MODULE_LICENSE("GPL");
 919 module_init(ocfs2_user_plugin_init);
 920 module_exit(ocfs2_user_plugin_exit);