1 /* 2 * Copyright (C) 2006-2010 Red Hat, Inc. All rights reserved. 3 * 4 * This copyrighted material is made available to anyone wishing to use, 5 * modify, copy, or redistribute it subject to the terms and conditions 6 * of the GNU General Public License v.2. 7 */ 8 9 #include <linux/miscdevice.h> 10 #include <linux/init.h> 11 #include <linux/wait.h> 12 #include <linux/file.h> 13 #include <linux/fs.h> 14 #include <linux/poll.h> 15 #include <linux/signal.h> 16 #include <linux/spinlock.h> 17 #include <linux/dlm.h> 18 #include <linux/dlm_device.h> 19 #include <linux/slab.h> 20 21 #include "dlm_internal.h" 22 #include "lockspace.h" 23 #include "lock.h" 24 #include "lvb_table.h" 25 #include "user.h" 26 #include "ast.h" 27 28 static const char name_prefix[] = "dlm"; 29 static const struct file_operations device_fops; 30 static atomic_t dlm_monitor_opened; 31 static int dlm_monitor_unused = 1; 32 33 #ifdef CONFIG_COMPAT 34 35 struct dlm_lock_params32 { 36 __u8 mode; 37 __u8 namelen; 38 __u16 unused; 39 __u32 flags; 40 __u32 lkid; 41 __u32 parent; 42 __u64 xid; 43 __u64 timeout; 44 __u32 castparam; 45 __u32 castaddr; 46 __u32 bastparam; 47 __u32 bastaddr; 48 __u32 lksb; 49 char lvb[DLM_USER_LVB_LEN]; 50 char name[0]; 51 }; 52 53 struct dlm_write_request32 { 54 __u32 version[3]; 55 __u8 cmd; 56 __u8 is64bit; 57 __u8 unused[2]; 58 59 union { 60 struct dlm_lock_params32 lock; 61 struct dlm_lspace_params lspace; 62 struct dlm_purge_params purge; 63 } i; 64 }; 65 66 struct dlm_lksb32 { 67 __u32 sb_status; 68 __u32 sb_lkid; 69 __u8 sb_flags; 70 __u32 sb_lvbptr; 71 }; 72 73 struct dlm_lock_result32 { 74 __u32 version[3]; 75 __u32 length; 76 __u32 user_astaddr; 77 __u32 user_astparam; 78 __u32 user_lksb; 79 struct dlm_lksb32 lksb; 80 __u8 bast_mode; 81 __u8 unused[3]; 82 /* Offsets may be zero if no data is present */ 83 __u32 lvb_offset; 84 }; 85 86 static void compat_input(struct dlm_write_request *kb, 87 struct dlm_write_request32 *kb32, 88 int namelen) 89 { 90 kb->version[0] = kb32->version[0]; 91 kb->version[1] = kb32->version[1]; 92 kb->version[2] = kb32->version[2]; 93 94 kb->cmd = kb32->cmd; 95 kb->is64bit = kb32->is64bit; 96 if (kb->cmd == DLM_USER_CREATE_LOCKSPACE || 97 kb->cmd == DLM_USER_REMOVE_LOCKSPACE) { 98 kb->i.lspace.flags = kb32->i.lspace.flags; 99 kb->i.lspace.minor = kb32->i.lspace.minor; 100 memcpy(kb->i.lspace.name, kb32->i.lspace.name, namelen); 101 } else if (kb->cmd == DLM_USER_PURGE) { 102 kb->i.purge.nodeid = kb32->i.purge.nodeid; 103 kb->i.purge.pid = kb32->i.purge.pid; 104 } else { 105 kb->i.lock.mode = kb32->i.lock.mode; 106 kb->i.lock.namelen = kb32->i.lock.namelen; 107 kb->i.lock.flags = kb32->i.lock.flags; 108 kb->i.lock.lkid = kb32->i.lock.lkid; 109 kb->i.lock.parent = kb32->i.lock.parent; 110 kb->i.lock.xid = kb32->i.lock.xid; 111 kb->i.lock.timeout = kb32->i.lock.timeout; 112 kb->i.lock.castparam = (void *)(long)kb32->i.lock.castparam; 113 kb->i.lock.castaddr = (void *)(long)kb32->i.lock.castaddr; 114 kb->i.lock.bastparam = (void *)(long)kb32->i.lock.bastparam; 115 kb->i.lock.bastaddr = (void *)(long)kb32->i.lock.bastaddr; 116 kb->i.lock.lksb = (void *)(long)kb32->i.lock.lksb; 117 memcpy(kb->i.lock.lvb, kb32->i.lock.lvb, DLM_USER_LVB_LEN); 118 memcpy(kb->i.lock.name, kb32->i.lock.name, namelen); 119 } 120 } 121 122 static void compat_output(struct dlm_lock_result *res, 123 struct dlm_lock_result32 *res32) 124 { 125 res32->version[0] = res->version[0]; 126 res32->version[1] = res->version[1]; 127 res32->version[2] = res->version[2]; 128 129 res32->user_astaddr = (__u32)(long)res->user_astaddr; 130 res32->user_astparam = (__u32)(long)res->user_astparam; 131 res32->user_lksb = (__u32)(long)res->user_lksb; 132 res32->bast_mode = res->bast_mode; 133 134 res32->lvb_offset = res->lvb_offset; 135 res32->length = res->length; 136 137 res32->lksb.sb_status = res->lksb.sb_status; 138 res32->lksb.sb_flags = res->lksb.sb_flags; 139 res32->lksb.sb_lkid = res->lksb.sb_lkid; 140 res32->lksb.sb_lvbptr = (__u32)(long)res->lksb.sb_lvbptr; 141 } 142 #endif 143 144 /* Figure out if this lock is at the end of its life and no longer 145 available for the application to use. The lkb still exists until 146 the final ast is read. A lock becomes EOL in three situations: 147 1. a noqueue request fails with EAGAIN 148 2. an unlock completes with EUNLOCK 149 3. a cancel of a waiting request completes with ECANCEL/EDEADLK 150 An EOL lock needs to be removed from the process's list of locks. 151 And we can't allow any new operation on an EOL lock. This is 152 not related to the lifetime of the lkb struct which is managed 153 entirely by refcount. */ 154 155 static int lkb_is_endoflife(int mode, int status) 156 { 157 switch (status) { 158 case -DLM_EUNLOCK: 159 return 1; 160 case -DLM_ECANCEL: 161 case -ETIMEDOUT: 162 case -EDEADLK: 163 case -EAGAIN: 164 if (mode == DLM_LOCK_IV) 165 return 1; 166 break; 167 } 168 return 0; 169 } 170 171 /* we could possibly check if the cancel of an orphan has resulted in the lkb 172 being removed and then remove that lkb from the orphans list and free it */ 173 174 void dlm_user_add_ast(struct dlm_lkb *lkb, uint32_t flags, int mode, 175 int status, uint32_t sbflags, uint64_t seq) 176 { 177 struct dlm_ls *ls; 178 struct dlm_user_args *ua; 179 struct dlm_user_proc *proc; 180 int rv; 181 182 if (lkb->lkb_flags & (DLM_IFL_ORPHAN | DLM_IFL_DEAD)) 183 return; 184 185 ls = lkb->lkb_resource->res_ls; 186 mutex_lock(&ls->ls_clear_proc_locks); 187 188 /* If ORPHAN/DEAD flag is set, it means the process is dead so an ast 189 can't be delivered. For ORPHAN's, dlm_clear_proc_locks() freed 190 lkb->ua so we can't try to use it. This second check is necessary 191 for cases where a completion ast is received for an operation that 192 began before clear_proc_locks did its cancel/unlock. */ 193 194 if (lkb->lkb_flags & (DLM_IFL_ORPHAN | DLM_IFL_DEAD)) 195 goto out; 196 197 DLM_ASSERT(lkb->lkb_ua, dlm_print_lkb(lkb);); 198 ua = lkb->lkb_ua; 199 proc = ua->proc; 200 201 if ((flags & DLM_CB_BAST) && ua->bastaddr == NULL) 202 goto out; 203 204 if ((flags & DLM_CB_CAST) && lkb_is_endoflife(mode, status)) 205 lkb->lkb_flags |= DLM_IFL_ENDOFLIFE; 206 207 spin_lock(&proc->asts_spin); 208 209 rv = dlm_add_lkb_callback(lkb, flags, mode, status, sbflags, seq); 210 if (rv < 0) { 211 spin_unlock(&proc->asts_spin); 212 goto out; 213 } 214 215 if (list_empty(&lkb->lkb_cb_list)) { 216 kref_get(&lkb->lkb_ref); 217 list_add_tail(&lkb->lkb_cb_list, &proc->asts); 218 wake_up_interruptible(&proc->wait); 219 } 220 spin_unlock(&proc->asts_spin); 221 222 if (lkb->lkb_flags & DLM_IFL_ENDOFLIFE) { 223 /* N.B. spin_lock locks_spin, not asts_spin */ 224 spin_lock(&proc->locks_spin); 225 if (!list_empty(&lkb->lkb_ownqueue)) { 226 list_del_init(&lkb->lkb_ownqueue); 227 dlm_put_lkb(lkb); 228 } 229 spin_unlock(&proc->locks_spin); 230 } 231 out: 232 mutex_unlock(&ls->ls_clear_proc_locks); 233 } 234 235 static int device_user_lock(struct dlm_user_proc *proc, 236 struct dlm_lock_params *params) 237 { 238 struct dlm_ls *ls; 239 struct dlm_user_args *ua; 240 uint32_t lkid; 241 int error = -ENOMEM; 242 243 ls = dlm_find_lockspace_local(proc->lockspace); 244 if (!ls) 245 return -ENOENT; 246 247 if (!params->castaddr || !params->lksb) { 248 error = -EINVAL; 249 goto out; 250 } 251 252 ua = kzalloc(sizeof(struct dlm_user_args), GFP_NOFS); 253 if (!ua) 254 goto out; 255 ua->proc = proc; 256 ua->user_lksb = params->lksb; 257 ua->castparam = params->castparam; 258 ua->castaddr = params->castaddr; 259 ua->bastparam = params->bastparam; 260 ua->bastaddr = params->bastaddr; 261 ua->xid = params->xid; 262 263 if (params->flags & DLM_LKF_CONVERT) { 264 error = dlm_user_convert(ls, ua, 265 params->mode, params->flags, 266 params->lkid, params->lvb, 267 (unsigned long) params->timeout); 268 } else if (params->flags & DLM_LKF_ORPHAN) { 269 error = dlm_user_adopt_orphan(ls, ua, 270 params->mode, params->flags, 271 params->name, params->namelen, 272 (unsigned long) params->timeout, 273 &lkid); 274 if (!error) 275 error = lkid; 276 } else { 277 error = dlm_user_request(ls, ua, 278 params->mode, params->flags, 279 params->name, params->namelen, 280 (unsigned long) params->timeout); 281 if (!error) 282 error = ua->lksb.sb_lkid; 283 } 284 out: 285 dlm_put_lockspace(ls); 286 return error; 287 } 288 289 static int device_user_unlock(struct dlm_user_proc *proc, 290 struct dlm_lock_params *params) 291 { 292 struct dlm_ls *ls; 293 struct dlm_user_args *ua; 294 int error = -ENOMEM; 295 296 ls = dlm_find_lockspace_local(proc->lockspace); 297 if (!ls) 298 return -ENOENT; 299 300 ua = kzalloc(sizeof(struct dlm_user_args), GFP_NOFS); 301 if (!ua) 302 goto out; 303 ua->proc = proc; 304 ua->user_lksb = params->lksb; 305 ua->castparam = params->castparam; 306 ua->castaddr = params->castaddr; 307 308 if (params->flags & DLM_LKF_CANCEL) 309 error = dlm_user_cancel(ls, ua, params->flags, params->lkid); 310 else 311 error = dlm_user_unlock(ls, ua, params->flags, params->lkid, 312 params->lvb); 313 out: 314 dlm_put_lockspace(ls); 315 return error; 316 } 317 318 static int device_user_deadlock(struct dlm_user_proc *proc, 319 struct dlm_lock_params *params) 320 { 321 struct dlm_ls *ls; 322 int error; 323 324 ls = dlm_find_lockspace_local(proc->lockspace); 325 if (!ls) 326 return -ENOENT; 327 328 error = dlm_user_deadlock(ls, params->flags, params->lkid); 329 330 dlm_put_lockspace(ls); 331 return error; 332 } 333 334 static int dlm_device_register(struct dlm_ls *ls, char *name) 335 { 336 int error, len; 337 338 /* The device is already registered. This happens when the 339 lockspace is created multiple times from userspace. */ 340 if (ls->ls_device.name) 341 return 0; 342 343 error = -ENOMEM; 344 len = strlen(name) + strlen(name_prefix) + 2; 345 ls->ls_device.name = kzalloc(len, GFP_NOFS); 346 if (!ls->ls_device.name) 347 goto fail; 348 349 snprintf((char *)ls->ls_device.name, len, "%s_%s", name_prefix, 350 name); 351 ls->ls_device.fops = &device_fops; 352 ls->ls_device.minor = MISC_DYNAMIC_MINOR; 353 354 error = misc_register(&ls->ls_device); 355 if (error) { 356 kfree(ls->ls_device.name); 357 } 358 fail: 359 return error; 360 } 361 362 int dlm_device_deregister(struct dlm_ls *ls) 363 { 364 /* The device is not registered. This happens when the lockspace 365 was never used from userspace, or when device_create_lockspace() 366 calls dlm_release_lockspace() after the register fails. */ 367 if (!ls->ls_device.name) 368 return 0; 369 370 misc_deregister(&ls->ls_device); 371 kfree(ls->ls_device.name); 372 return 0; 373 } 374 375 static int device_user_purge(struct dlm_user_proc *proc, 376 struct dlm_purge_params *params) 377 { 378 struct dlm_ls *ls; 379 int error; 380 381 ls = dlm_find_lockspace_local(proc->lockspace); 382 if (!ls) 383 return -ENOENT; 384 385 error = dlm_user_purge(ls, proc, params->nodeid, params->pid); 386 387 dlm_put_lockspace(ls); 388 return error; 389 } 390 391 static int device_create_lockspace(struct dlm_lspace_params *params) 392 { 393 dlm_lockspace_t *lockspace; 394 struct dlm_ls *ls; 395 int error; 396 397 if (!capable(CAP_SYS_ADMIN)) 398 return -EPERM; 399 400 error = dlm_new_lockspace(params->name, NULL, params->flags, 401 DLM_USER_LVB_LEN, NULL, NULL, NULL, 402 &lockspace); 403 if (error) 404 return error; 405 406 ls = dlm_find_lockspace_local(lockspace); 407 if (!ls) 408 return -ENOENT; 409 410 error = dlm_device_register(ls, params->name); 411 dlm_put_lockspace(ls); 412 413 if (error) 414 dlm_release_lockspace(lockspace, 0); 415 else 416 error = ls->ls_device.minor; 417 418 return error; 419 } 420 421 static int device_remove_lockspace(struct dlm_lspace_params *params) 422 { 423 dlm_lockspace_t *lockspace; 424 struct dlm_ls *ls; 425 int error, force = 0; 426 427 if (!capable(CAP_SYS_ADMIN)) 428 return -EPERM; 429 430 ls = dlm_find_lockspace_device(params->minor); 431 if (!ls) 432 return -ENOENT; 433 434 if (params->flags & DLM_USER_LSFLG_FORCEFREE) 435 force = 2; 436 437 lockspace = ls->ls_local_handle; 438 dlm_put_lockspace(ls); 439 440 /* The final dlm_release_lockspace waits for references to go to 441 zero, so all processes will need to close their device for the 442 ls before the release will proceed. release also calls the 443 device_deregister above. Converting a positive return value 444 from release to zero means that userspace won't know when its 445 release was the final one, but it shouldn't need to know. */ 446 447 error = dlm_release_lockspace(lockspace, force); 448 if (error > 0) 449 error = 0; 450 return error; 451 } 452 453 /* Check the user's version matches ours */ 454 static int check_version(struct dlm_write_request *req) 455 { 456 if (req->version[0] != DLM_DEVICE_VERSION_MAJOR || 457 (req->version[0] == DLM_DEVICE_VERSION_MAJOR && 458 req->version[1] > DLM_DEVICE_VERSION_MINOR)) { 459 460 printk(KERN_DEBUG "dlm: process %s (%d) version mismatch " 461 "user (%d.%d.%d) kernel (%d.%d.%d)\n", 462 current->comm, 463 task_pid_nr(current), 464 req->version[0], 465 req->version[1], 466 req->version[2], 467 DLM_DEVICE_VERSION_MAJOR, 468 DLM_DEVICE_VERSION_MINOR, 469 DLM_DEVICE_VERSION_PATCH); 470 return -EINVAL; 471 } 472 return 0; 473 } 474 475 /* 476 * device_write 477 * 478 * device_user_lock 479 * dlm_user_request -> request_lock 480 * dlm_user_convert -> convert_lock 481 * 482 * device_user_unlock 483 * dlm_user_unlock -> unlock_lock 484 * dlm_user_cancel -> cancel_lock 485 * 486 * device_create_lockspace 487 * dlm_new_lockspace 488 * 489 * device_remove_lockspace 490 * dlm_release_lockspace 491 */ 492 493 /* a write to a lockspace device is a lock or unlock request, a write 494 to the control device is to create/remove a lockspace */ 495 496 static ssize_t device_write(struct file *file, const char __user *buf, 497 size_t count, loff_t *ppos) 498 { 499 struct dlm_user_proc *proc = file->private_data; 500 struct dlm_write_request *kbuf; 501 int error; 502 503 #ifdef CONFIG_COMPAT 504 if (count < sizeof(struct dlm_write_request32)) 505 #else 506 if (count < sizeof(struct dlm_write_request)) 507 #endif 508 return -EINVAL; 509 510 /* 511 * can't compare against COMPAT/dlm_write_request32 because 512 * we don't yet know if is64bit is zero 513 */ 514 if (count > sizeof(struct dlm_write_request) + DLM_RESNAME_MAXLEN) 515 return -EINVAL; 516 517 kbuf = memdup_user_nul(buf, count); 518 if (IS_ERR(kbuf)) 519 return PTR_ERR(kbuf); 520 521 if (check_version(kbuf)) { 522 error = -EBADE; 523 goto out_free; 524 } 525 526 #ifdef CONFIG_COMPAT 527 if (!kbuf->is64bit) { 528 struct dlm_write_request32 *k32buf; 529 int namelen = 0; 530 531 if (count > sizeof(struct dlm_write_request32)) 532 namelen = count - sizeof(struct dlm_write_request32); 533 534 k32buf = (struct dlm_write_request32 *)kbuf; 535 536 /* add 1 after namelen so that the name string is terminated */ 537 kbuf = kzalloc(sizeof(struct dlm_write_request) + namelen + 1, 538 GFP_NOFS); 539 if (!kbuf) { 540 kfree(k32buf); 541 return -ENOMEM; 542 } 543 544 if (proc) 545 set_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags); 546 547 compat_input(kbuf, k32buf, namelen); 548 kfree(k32buf); 549 } 550 #endif 551 552 /* do we really need this? can a write happen after a close? */ 553 if ((kbuf->cmd == DLM_USER_LOCK || kbuf->cmd == DLM_USER_UNLOCK) && 554 (proc && test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))) { 555 error = -EINVAL; 556 goto out_free; 557 } 558 559 error = -EINVAL; 560 561 switch (kbuf->cmd) 562 { 563 case DLM_USER_LOCK: 564 if (!proc) { 565 log_print("no locking on control device"); 566 goto out_free; 567 } 568 error = device_user_lock(proc, &kbuf->i.lock); 569 break; 570 571 case DLM_USER_UNLOCK: 572 if (!proc) { 573 log_print("no locking on control device"); 574 goto out_free; 575 } 576 error = device_user_unlock(proc, &kbuf->i.lock); 577 break; 578 579 case DLM_USER_DEADLOCK: 580 if (!proc) { 581 log_print("no locking on control device"); 582 goto out_free; 583 } 584 error = device_user_deadlock(proc, &kbuf->i.lock); 585 break; 586 587 case DLM_USER_CREATE_LOCKSPACE: 588 if (proc) { 589 log_print("create/remove only on control device"); 590 goto out_free; 591 } 592 error = device_create_lockspace(&kbuf->i.lspace); 593 break; 594 595 case DLM_USER_REMOVE_LOCKSPACE: 596 if (proc) { 597 log_print("create/remove only on control device"); 598 goto out_free; 599 } 600 error = device_remove_lockspace(&kbuf->i.lspace); 601 break; 602 603 case DLM_USER_PURGE: 604 if (!proc) { 605 log_print("no locking on control device"); 606 goto out_free; 607 } 608 error = device_user_purge(proc, &kbuf->i.purge); 609 break; 610 611 default: 612 log_print("Unknown command passed to DLM device : %d\n", 613 kbuf->cmd); 614 } 615 616 out_free: 617 kfree(kbuf); 618 return error; 619 } 620 621 /* Every process that opens the lockspace device has its own "proc" structure 622 hanging off the open file that's used to keep track of locks owned by the 623 process and asts that need to be delivered to the process. */ 624 625 static int device_open(struct inode *inode, struct file *file) 626 { 627 struct dlm_user_proc *proc; 628 struct dlm_ls *ls; 629 630 ls = dlm_find_lockspace_device(iminor(inode)); 631 if (!ls) 632 return -ENOENT; 633 634 proc = kzalloc(sizeof(struct dlm_user_proc), GFP_NOFS); 635 if (!proc) { 636 dlm_put_lockspace(ls); 637 return -ENOMEM; 638 } 639 640 proc->lockspace = ls->ls_local_handle; 641 INIT_LIST_HEAD(&proc->asts); 642 INIT_LIST_HEAD(&proc->locks); 643 INIT_LIST_HEAD(&proc->unlocking); 644 spin_lock_init(&proc->asts_spin); 645 spin_lock_init(&proc->locks_spin); 646 init_waitqueue_head(&proc->wait); 647 file->private_data = proc; 648 649 return 0; 650 } 651 652 static int device_close(struct inode *inode, struct file *file) 653 { 654 struct dlm_user_proc *proc = file->private_data; 655 struct dlm_ls *ls; 656 657 ls = dlm_find_lockspace_local(proc->lockspace); 658 if (!ls) 659 return -ENOENT; 660 661 set_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags); 662 663 dlm_clear_proc_locks(ls, proc); 664 665 /* at this point no more lkb's should exist for this lockspace, 666 so there's no chance of dlm_user_add_ast() being called and 667 looking for lkb->ua->proc */ 668 669 kfree(proc); 670 file->private_data = NULL; 671 672 dlm_put_lockspace(ls); 673 dlm_put_lockspace(ls); /* for the find in device_open() */ 674 675 /* FIXME: AUTOFREE: if this ls is no longer used do 676 device_remove_lockspace() */ 677 678 return 0; 679 } 680 681 static int copy_result_to_user(struct dlm_user_args *ua, int compat, 682 uint32_t flags, int mode, int copy_lvb, 683 char __user *buf, size_t count) 684 { 685 #ifdef CONFIG_COMPAT 686 struct dlm_lock_result32 result32; 687 #endif 688 struct dlm_lock_result result; 689 void *resultptr; 690 int error=0; 691 int len; 692 int struct_len; 693 694 memset(&result, 0, sizeof(struct dlm_lock_result)); 695 result.version[0] = DLM_DEVICE_VERSION_MAJOR; 696 result.version[1] = DLM_DEVICE_VERSION_MINOR; 697 result.version[2] = DLM_DEVICE_VERSION_PATCH; 698 memcpy(&result.lksb, &ua->lksb, sizeof(struct dlm_lksb)); 699 result.user_lksb = ua->user_lksb; 700 701 /* FIXME: dlm1 provides for the user's bastparam/addr to not be updated 702 in a conversion unless the conversion is successful. See code 703 in dlm_user_convert() for updating ua from ua_tmp. OpenVMS, though, 704 notes that a new blocking AST address and parameter are set even if 705 the conversion fails, so maybe we should just do that. */ 706 707 if (flags & DLM_CB_BAST) { 708 result.user_astaddr = ua->bastaddr; 709 result.user_astparam = ua->bastparam; 710 result.bast_mode = mode; 711 } else { 712 result.user_astaddr = ua->castaddr; 713 result.user_astparam = ua->castparam; 714 } 715 716 #ifdef CONFIG_COMPAT 717 if (compat) 718 len = sizeof(struct dlm_lock_result32); 719 else 720 #endif 721 len = sizeof(struct dlm_lock_result); 722 struct_len = len; 723 724 /* copy lvb to userspace if there is one, it's been updated, and 725 the user buffer has space for it */ 726 727 if (copy_lvb && ua->lksb.sb_lvbptr && count >= len + DLM_USER_LVB_LEN) { 728 if (copy_to_user(buf+len, ua->lksb.sb_lvbptr, 729 DLM_USER_LVB_LEN)) { 730 error = -EFAULT; 731 goto out; 732 } 733 734 result.lvb_offset = len; 735 len += DLM_USER_LVB_LEN; 736 } 737 738 result.length = len; 739 resultptr = &result; 740 #ifdef CONFIG_COMPAT 741 if (compat) { 742 compat_output(&result, &result32); 743 resultptr = &result32; 744 } 745 #endif 746 747 if (copy_to_user(buf, resultptr, struct_len)) 748 error = -EFAULT; 749 else 750 error = len; 751 out: 752 return error; 753 } 754 755 static int copy_version_to_user(char __user *buf, size_t count) 756 { 757 struct dlm_device_version ver; 758 759 memset(&ver, 0, sizeof(struct dlm_device_version)); 760 ver.version[0] = DLM_DEVICE_VERSION_MAJOR; 761 ver.version[1] = DLM_DEVICE_VERSION_MINOR; 762 ver.version[2] = DLM_DEVICE_VERSION_PATCH; 763 764 if (copy_to_user(buf, &ver, sizeof(struct dlm_device_version))) 765 return -EFAULT; 766 return sizeof(struct dlm_device_version); 767 } 768 769 /* a read returns a single ast described in a struct dlm_lock_result */ 770 771 static ssize_t device_read(struct file *file, char __user *buf, size_t count, 772 loff_t *ppos) 773 { 774 struct dlm_user_proc *proc = file->private_data; 775 struct dlm_lkb *lkb; 776 DECLARE_WAITQUEUE(wait, current); 777 struct dlm_callback cb; 778 int rv, resid, copy_lvb = 0; 779 int old_mode, new_mode; 780 781 if (count == sizeof(struct dlm_device_version)) { 782 rv = copy_version_to_user(buf, count); 783 return rv; 784 } 785 786 if (!proc) { 787 log_print("non-version read from control device %zu", count); 788 return -EINVAL; 789 } 790 791 #ifdef CONFIG_COMPAT 792 if (count < sizeof(struct dlm_lock_result32)) 793 #else 794 if (count < sizeof(struct dlm_lock_result)) 795 #endif 796 return -EINVAL; 797 798 try_another: 799 800 /* do we really need this? can a read happen after a close? */ 801 if (test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags)) 802 return -EINVAL; 803 804 spin_lock(&proc->asts_spin); 805 if (list_empty(&proc->asts)) { 806 if (file->f_flags & O_NONBLOCK) { 807 spin_unlock(&proc->asts_spin); 808 return -EAGAIN; 809 } 810 811 add_wait_queue(&proc->wait, &wait); 812 813 repeat: 814 set_current_state(TASK_INTERRUPTIBLE); 815 if (list_empty(&proc->asts) && !signal_pending(current)) { 816 spin_unlock(&proc->asts_spin); 817 schedule(); 818 spin_lock(&proc->asts_spin); 819 goto repeat; 820 } 821 set_current_state(TASK_RUNNING); 822 remove_wait_queue(&proc->wait, &wait); 823 824 if (signal_pending(current)) { 825 spin_unlock(&proc->asts_spin); 826 return -ERESTARTSYS; 827 } 828 } 829 830 /* if we empty lkb_callbacks, we don't want to unlock the spinlock 831 without removing lkb_cb_list; so empty lkb_cb_list is always 832 consistent with empty lkb_callbacks */ 833 834 lkb = list_entry(proc->asts.next, struct dlm_lkb, lkb_cb_list); 835 836 /* rem_lkb_callback sets a new lkb_last_cast */ 837 old_mode = lkb->lkb_last_cast.mode; 838 839 rv = dlm_rem_lkb_callback(lkb->lkb_resource->res_ls, lkb, &cb, &resid); 840 if (rv < 0) { 841 /* this shouldn't happen; lkb should have been removed from 842 list when resid was zero */ 843 log_print("dlm_rem_lkb_callback empty %x", lkb->lkb_id); 844 list_del_init(&lkb->lkb_cb_list); 845 spin_unlock(&proc->asts_spin); 846 /* removes ref for proc->asts, may cause lkb to be freed */ 847 dlm_put_lkb(lkb); 848 goto try_another; 849 } 850 if (!resid) 851 list_del_init(&lkb->lkb_cb_list); 852 spin_unlock(&proc->asts_spin); 853 854 if (cb.flags & DLM_CB_SKIP) { 855 /* removes ref for proc->asts, may cause lkb to be freed */ 856 if (!resid) 857 dlm_put_lkb(lkb); 858 goto try_another; 859 } 860 861 if (cb.flags & DLM_CB_CAST) { 862 new_mode = cb.mode; 863 864 if (!cb.sb_status && lkb->lkb_lksb->sb_lvbptr && 865 dlm_lvb_operations[old_mode + 1][new_mode + 1]) 866 copy_lvb = 1; 867 868 lkb->lkb_lksb->sb_status = cb.sb_status; 869 lkb->lkb_lksb->sb_flags = cb.sb_flags; 870 } 871 872 rv = copy_result_to_user(lkb->lkb_ua, 873 test_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags), 874 cb.flags, cb.mode, copy_lvb, buf, count); 875 876 /* removes ref for proc->asts, may cause lkb to be freed */ 877 if (!resid) 878 dlm_put_lkb(lkb); 879 880 return rv; 881 } 882 883 static unsigned int device_poll(struct file *file, poll_table *wait) 884 { 885 struct dlm_user_proc *proc = file->private_data; 886 887 poll_wait(file, &proc->wait, wait); 888 889 spin_lock(&proc->asts_spin); 890 if (!list_empty(&proc->asts)) { 891 spin_unlock(&proc->asts_spin); 892 return POLLIN | POLLRDNORM; 893 } 894 spin_unlock(&proc->asts_spin); 895 return 0; 896 } 897 898 int dlm_user_daemon_available(void) 899 { 900 /* dlm_controld hasn't started (or, has started, but not 901 properly populated configfs) */ 902 903 if (!dlm_our_nodeid()) 904 return 0; 905 906 /* This is to deal with versions of dlm_controld that don't 907 know about the monitor device. We assume that if the 908 dlm_controld was started (above), but the monitor device 909 was never opened, that it's an old version. dlm_controld 910 should open the monitor device before populating configfs. */ 911 912 if (dlm_monitor_unused) 913 return 1; 914 915 return atomic_read(&dlm_monitor_opened) ? 1 : 0; 916 } 917 918 static int ctl_device_open(struct inode *inode, struct file *file) 919 { 920 file->private_data = NULL; 921 return 0; 922 } 923 924 static int ctl_device_close(struct inode *inode, struct file *file) 925 { 926 return 0; 927 } 928 929 static int monitor_device_open(struct inode *inode, struct file *file) 930 { 931 atomic_inc(&dlm_monitor_opened); 932 dlm_monitor_unused = 0; 933 return 0; 934 } 935 936 static int monitor_device_close(struct inode *inode, struct file *file) 937 { 938 if (atomic_dec_and_test(&dlm_monitor_opened)) 939 dlm_stop_lockspaces(); 940 return 0; 941 } 942 943 static const struct file_operations device_fops = { 944 .open = device_open, 945 .release = device_close, 946 .read = device_read, 947 .write = device_write, 948 .poll = device_poll, 949 .owner = THIS_MODULE, 950 .llseek = noop_llseek, 951 }; 952 953 static const struct file_operations ctl_device_fops = { 954 .open = ctl_device_open, 955 .release = ctl_device_close, 956 .read = device_read, 957 .write = device_write, 958 .owner = THIS_MODULE, 959 .llseek = noop_llseek, 960 }; 961 962 static struct miscdevice ctl_device = { 963 .name = "dlm-control", 964 .fops = &ctl_device_fops, 965 .minor = MISC_DYNAMIC_MINOR, 966 }; 967 968 static const struct file_operations monitor_device_fops = { 969 .open = monitor_device_open, 970 .release = monitor_device_close, 971 .owner = THIS_MODULE, 972 .llseek = noop_llseek, 973 }; 974 975 static struct miscdevice monitor_device = { 976 .name = "dlm-monitor", 977 .fops = &monitor_device_fops, 978 .minor = MISC_DYNAMIC_MINOR, 979 }; 980 981 int __init dlm_user_init(void) 982 { 983 int error; 984 985 atomic_set(&dlm_monitor_opened, 0); 986 987 error = misc_register(&ctl_device); 988 if (error) { 989 log_print("misc_register failed for control device"); 990 goto out; 991 } 992 993 error = misc_register(&monitor_device); 994 if (error) { 995 log_print("misc_register failed for monitor device"); 996 misc_deregister(&ctl_device); 997 } 998 out: 999 return error; 1000 } 1001 1002 void dlm_user_exit(void) 1003 { 1004 misc_deregister(&ctl_device); 1005 misc_deregister(&monitor_device); 1006 } 1007 1008