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/module.h> 13 #include <linux/file.h> 14 #include <linux/fs.h> 15 #include <linux/poll.h> 16 #include <linux/signal.h> 17 #include <linux/spinlock.h> 18 #include <linux/dlm.h> 19 #include <linux/dlm_device.h> 20 #include <linux/slab.h> 21 22 #include "dlm_internal.h" 23 #include "lockspace.h" 24 #include "lock.h" 25 #include "lvb_table.h" 26 #include "user.h" 27 #include "ast.h" 28 29 static const char name_prefix[] = "dlm"; 30 static const struct file_operations device_fops; 31 static atomic_t dlm_monitor_opened; 32 static int dlm_monitor_unused = 1; 33 34 #ifdef CONFIG_COMPAT 35 36 struct dlm_lock_params32 { 37 __u8 mode; 38 __u8 namelen; 39 __u16 unused; 40 __u32 flags; 41 __u32 lkid; 42 __u32 parent; 43 __u64 xid; 44 __u64 timeout; 45 __u32 castparam; 46 __u32 castaddr; 47 __u32 bastparam; 48 __u32 bastaddr; 49 __u32 lksb; 50 char lvb[DLM_USER_LVB_LEN]; 51 char name[0]; 52 }; 53 54 struct dlm_write_request32 { 55 __u32 version[3]; 56 __u8 cmd; 57 __u8 is64bit; 58 __u8 unused[2]; 59 60 union { 61 struct dlm_lock_params32 lock; 62 struct dlm_lspace_params lspace; 63 struct dlm_purge_params purge; 64 } i; 65 }; 66 67 struct dlm_lksb32 { 68 __u32 sb_status; 69 __u32 sb_lkid; 70 __u8 sb_flags; 71 __u32 sb_lvbptr; 72 }; 73 74 struct dlm_lock_result32 { 75 __u32 version[3]; 76 __u32 length; 77 __u32 user_astaddr; 78 __u32 user_astparam; 79 __u32 user_lksb; 80 struct dlm_lksb32 lksb; 81 __u8 bast_mode; 82 __u8 unused[3]; 83 /* Offsets may be zero if no data is present */ 84 __u32 lvb_offset; 85 }; 86 87 static void compat_input(struct dlm_write_request *kb, 88 struct dlm_write_request32 *kb32, 89 int namelen) 90 { 91 kb->version[0] = kb32->version[0]; 92 kb->version[1] = kb32->version[1]; 93 kb->version[2] = kb32->version[2]; 94 95 kb->cmd = kb32->cmd; 96 kb->is64bit = kb32->is64bit; 97 if (kb->cmd == DLM_USER_CREATE_LOCKSPACE || 98 kb->cmd == DLM_USER_REMOVE_LOCKSPACE) { 99 kb->i.lspace.flags = kb32->i.lspace.flags; 100 kb->i.lspace.minor = kb32->i.lspace.minor; 101 memcpy(kb->i.lspace.name, kb32->i.lspace.name, namelen); 102 } else if (kb->cmd == DLM_USER_PURGE) { 103 kb->i.purge.nodeid = kb32->i.purge.nodeid; 104 kb->i.purge.pid = kb32->i.purge.pid; 105 } else { 106 kb->i.lock.mode = kb32->i.lock.mode; 107 kb->i.lock.namelen = kb32->i.lock.namelen; 108 kb->i.lock.flags = kb32->i.lock.flags; 109 kb->i.lock.lkid = kb32->i.lock.lkid; 110 kb->i.lock.parent = kb32->i.lock.parent; 111 kb->i.lock.xid = kb32->i.lock.xid; 112 kb->i.lock.timeout = kb32->i.lock.timeout; 113 kb->i.lock.castparam = (void *)(long)kb32->i.lock.castparam; 114 kb->i.lock.castaddr = (void *)(long)kb32->i.lock.castaddr; 115 kb->i.lock.bastparam = (void *)(long)kb32->i.lock.bastparam; 116 kb->i.lock.bastaddr = (void *)(long)kb32->i.lock.bastaddr; 117 kb->i.lock.lksb = (void *)(long)kb32->i.lock.lksb; 118 memcpy(kb->i.lock.lvb, kb32->i.lock.lvb, DLM_USER_LVB_LEN); 119 memcpy(kb->i.lock.name, kb32->i.lock.name, namelen); 120 } 121 } 122 123 static void compat_output(struct dlm_lock_result *res, 124 struct dlm_lock_result32 *res32) 125 { 126 res32->version[0] = res->version[0]; 127 res32->version[1] = res->version[1]; 128 res32->version[2] = res->version[2]; 129 130 res32->user_astaddr = (__u32)(long)res->user_astaddr; 131 res32->user_astparam = (__u32)(long)res->user_astparam; 132 res32->user_lksb = (__u32)(long)res->user_lksb; 133 res32->bast_mode = res->bast_mode; 134 135 res32->lvb_offset = res->lvb_offset; 136 res32->length = res->length; 137 138 res32->lksb.sb_status = res->lksb.sb_status; 139 res32->lksb.sb_flags = res->lksb.sb_flags; 140 res32->lksb.sb_lkid = res->lksb.sb_lkid; 141 res32->lksb.sb_lvbptr = (__u32)(long)res->lksb.sb_lvbptr; 142 } 143 #endif 144 145 /* Figure out if this lock is at the end of its life and no longer 146 available for the application to use. The lkb still exists until 147 the final ast is read. A lock becomes EOL in three situations: 148 1. a noqueue request fails with EAGAIN 149 2. an unlock completes with EUNLOCK 150 3. a cancel of a waiting request completes with ECANCEL/EDEADLK 151 An EOL lock needs to be removed from the process's list of locks. 152 And we can't allow any new operation on an EOL lock. This is 153 not related to the lifetime of the lkb struct which is managed 154 entirely by refcount. */ 155 156 static int lkb_is_endoflife(int mode, int status) 157 { 158 switch (status) { 159 case -DLM_EUNLOCK: 160 return 1; 161 case -DLM_ECANCEL: 162 case -ETIMEDOUT: 163 case -EDEADLK: 164 case -EAGAIN: 165 if (mode == DLM_LOCK_IV) 166 return 1; 167 break; 168 } 169 return 0; 170 } 171 172 /* we could possibly check if the cancel of an orphan has resulted in the lkb 173 being removed and then remove that lkb from the orphans list and free it */ 174 175 void dlm_user_add_ast(struct dlm_lkb *lkb, uint32_t flags, int mode, 176 int status, uint32_t sbflags, uint64_t seq) 177 { 178 struct dlm_ls *ls; 179 struct dlm_user_args *ua; 180 struct dlm_user_proc *proc; 181 int rv; 182 183 if (lkb->lkb_flags & (DLM_IFL_ORPHAN | DLM_IFL_DEAD)) 184 return; 185 186 ls = lkb->lkb_resource->res_ls; 187 mutex_lock(&ls->ls_clear_proc_locks); 188 189 /* If ORPHAN/DEAD flag is set, it means the process is dead so an ast 190 can't be delivered. For ORPHAN's, dlm_clear_proc_locks() freed 191 lkb->ua so we can't try to use it. This second check is necessary 192 for cases where a completion ast is received for an operation that 193 began before clear_proc_locks did its cancel/unlock. */ 194 195 if (lkb->lkb_flags & (DLM_IFL_ORPHAN | DLM_IFL_DEAD)) 196 goto out; 197 198 DLM_ASSERT(lkb->lkb_ua, dlm_print_lkb(lkb);); 199 ua = lkb->lkb_ua; 200 proc = ua->proc; 201 202 if ((flags & DLM_CB_BAST) && ua->bastaddr == NULL) 203 goto out; 204 205 if ((flags & DLM_CB_CAST) && lkb_is_endoflife(mode, status)) 206 lkb->lkb_flags |= DLM_IFL_ENDOFLIFE; 207 208 spin_lock(&proc->asts_spin); 209 210 rv = dlm_add_lkb_callback(lkb, flags, mode, status, sbflags, seq); 211 if (rv < 0) { 212 spin_unlock(&proc->asts_spin); 213 goto out; 214 } 215 216 if (list_empty(&lkb->lkb_cb_list)) { 217 kref_get(&lkb->lkb_ref); 218 list_add_tail(&lkb->lkb_cb_list, &proc->asts); 219 wake_up_interruptible(&proc->wait); 220 } 221 spin_unlock(&proc->asts_spin); 222 223 if (lkb->lkb_flags & DLM_IFL_ENDOFLIFE) { 224 /* N.B. spin_lock locks_spin, not asts_spin */ 225 spin_lock(&proc->locks_spin); 226 if (!list_empty(&lkb->lkb_ownqueue)) { 227 list_del_init(&lkb->lkb_ownqueue); 228 dlm_put_lkb(lkb); 229 } 230 spin_unlock(&proc->locks_spin); 231 } 232 out: 233 mutex_unlock(&ls->ls_clear_proc_locks); 234 } 235 236 static int device_user_lock(struct dlm_user_proc *proc, 237 struct dlm_lock_params *params) 238 { 239 struct dlm_ls *ls; 240 struct dlm_user_args *ua; 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 { 269 error = dlm_user_request(ls, ua, 270 params->mode, params->flags, 271 params->name, params->namelen, 272 (unsigned long) params->timeout); 273 if (!error) 274 error = ua->lksb.sb_lkid; 275 } 276 out: 277 dlm_put_lockspace(ls); 278 return error; 279 } 280 281 static int device_user_unlock(struct dlm_user_proc *proc, 282 struct dlm_lock_params *params) 283 { 284 struct dlm_ls *ls; 285 struct dlm_user_args *ua; 286 int error = -ENOMEM; 287 288 ls = dlm_find_lockspace_local(proc->lockspace); 289 if (!ls) 290 return -ENOENT; 291 292 ua = kzalloc(sizeof(struct dlm_user_args), GFP_NOFS); 293 if (!ua) 294 goto out; 295 ua->proc = proc; 296 ua->user_lksb = params->lksb; 297 ua->castparam = params->castparam; 298 ua->castaddr = params->castaddr; 299 300 if (params->flags & DLM_LKF_CANCEL) 301 error = dlm_user_cancel(ls, ua, params->flags, params->lkid); 302 else 303 error = dlm_user_unlock(ls, ua, params->flags, params->lkid, 304 params->lvb); 305 out: 306 dlm_put_lockspace(ls); 307 return error; 308 } 309 310 static int device_user_deadlock(struct dlm_user_proc *proc, 311 struct dlm_lock_params *params) 312 { 313 struct dlm_ls *ls; 314 int error; 315 316 ls = dlm_find_lockspace_local(proc->lockspace); 317 if (!ls) 318 return -ENOENT; 319 320 error = dlm_user_deadlock(ls, params->flags, params->lkid); 321 322 dlm_put_lockspace(ls); 323 return error; 324 } 325 326 static int dlm_device_register(struct dlm_ls *ls, char *name) 327 { 328 int error, len; 329 330 /* The device is already registered. This happens when the 331 lockspace is created multiple times from userspace. */ 332 if (ls->ls_device.name) 333 return 0; 334 335 error = -ENOMEM; 336 len = strlen(name) + strlen(name_prefix) + 2; 337 ls->ls_device.name = kzalloc(len, GFP_NOFS); 338 if (!ls->ls_device.name) 339 goto fail; 340 341 snprintf((char *)ls->ls_device.name, len, "%s_%s", name_prefix, 342 name); 343 ls->ls_device.fops = &device_fops; 344 ls->ls_device.minor = MISC_DYNAMIC_MINOR; 345 346 error = misc_register(&ls->ls_device); 347 if (error) { 348 kfree(ls->ls_device.name); 349 } 350 fail: 351 return error; 352 } 353 354 int dlm_device_deregister(struct dlm_ls *ls) 355 { 356 int error; 357 358 /* The device is not registered. This happens when the lockspace 359 was never used from userspace, or when device_create_lockspace() 360 calls dlm_release_lockspace() after the register fails. */ 361 if (!ls->ls_device.name) 362 return 0; 363 364 error = misc_deregister(&ls->ls_device); 365 if (!error) 366 kfree(ls->ls_device.name); 367 return error; 368 } 369 370 static int device_user_purge(struct dlm_user_proc *proc, 371 struct dlm_purge_params *params) 372 { 373 struct dlm_ls *ls; 374 int error; 375 376 ls = dlm_find_lockspace_local(proc->lockspace); 377 if (!ls) 378 return -ENOENT; 379 380 error = dlm_user_purge(ls, proc, params->nodeid, params->pid); 381 382 dlm_put_lockspace(ls); 383 return error; 384 } 385 386 static int device_create_lockspace(struct dlm_lspace_params *params) 387 { 388 dlm_lockspace_t *lockspace; 389 struct dlm_ls *ls; 390 int error; 391 392 if (!capable(CAP_SYS_ADMIN)) 393 return -EPERM; 394 395 error = dlm_new_lockspace(params->name, NULL, params->flags, 396 DLM_USER_LVB_LEN, NULL, NULL, NULL, 397 &lockspace); 398 if (error) 399 return error; 400 401 ls = dlm_find_lockspace_local(lockspace); 402 if (!ls) 403 return -ENOENT; 404 405 error = dlm_device_register(ls, params->name); 406 dlm_put_lockspace(ls); 407 408 if (error) 409 dlm_release_lockspace(lockspace, 0); 410 else 411 error = ls->ls_device.minor; 412 413 return error; 414 } 415 416 static int device_remove_lockspace(struct dlm_lspace_params *params) 417 { 418 dlm_lockspace_t *lockspace; 419 struct dlm_ls *ls; 420 int error, force = 0; 421 422 if (!capable(CAP_SYS_ADMIN)) 423 return -EPERM; 424 425 ls = dlm_find_lockspace_device(params->minor); 426 if (!ls) 427 return -ENOENT; 428 429 if (params->flags & DLM_USER_LSFLG_FORCEFREE) 430 force = 2; 431 432 lockspace = ls->ls_local_handle; 433 dlm_put_lockspace(ls); 434 435 /* The final dlm_release_lockspace waits for references to go to 436 zero, so all processes will need to close their device for the 437 ls before the release will proceed. release also calls the 438 device_deregister above. Converting a positive return value 439 from release to zero means that userspace won't know when its 440 release was the final one, but it shouldn't need to know. */ 441 442 error = dlm_release_lockspace(lockspace, force); 443 if (error > 0) 444 error = 0; 445 return error; 446 } 447 448 /* Check the user's version matches ours */ 449 static int check_version(struct dlm_write_request *req) 450 { 451 if (req->version[0] != DLM_DEVICE_VERSION_MAJOR || 452 (req->version[0] == DLM_DEVICE_VERSION_MAJOR && 453 req->version[1] > DLM_DEVICE_VERSION_MINOR)) { 454 455 printk(KERN_DEBUG "dlm: process %s (%d) version mismatch " 456 "user (%d.%d.%d) kernel (%d.%d.%d)\n", 457 current->comm, 458 task_pid_nr(current), 459 req->version[0], 460 req->version[1], 461 req->version[2], 462 DLM_DEVICE_VERSION_MAJOR, 463 DLM_DEVICE_VERSION_MINOR, 464 DLM_DEVICE_VERSION_PATCH); 465 return -EINVAL; 466 } 467 return 0; 468 } 469 470 /* 471 * device_write 472 * 473 * device_user_lock 474 * dlm_user_request -> request_lock 475 * dlm_user_convert -> convert_lock 476 * 477 * device_user_unlock 478 * dlm_user_unlock -> unlock_lock 479 * dlm_user_cancel -> cancel_lock 480 * 481 * device_create_lockspace 482 * dlm_new_lockspace 483 * 484 * device_remove_lockspace 485 * dlm_release_lockspace 486 */ 487 488 /* a write to a lockspace device is a lock or unlock request, a write 489 to the control device is to create/remove a lockspace */ 490 491 static ssize_t device_write(struct file *file, const char __user *buf, 492 size_t count, loff_t *ppos) 493 { 494 struct dlm_user_proc *proc = file->private_data; 495 struct dlm_write_request *kbuf; 496 int error; 497 498 #ifdef CONFIG_COMPAT 499 if (count < sizeof(struct dlm_write_request32)) 500 #else 501 if (count < sizeof(struct dlm_write_request)) 502 #endif 503 return -EINVAL; 504 505 /* 506 * can't compare against COMPAT/dlm_write_request32 because 507 * we don't yet know if is64bit is zero 508 */ 509 if (count > sizeof(struct dlm_write_request) + DLM_RESNAME_MAXLEN) 510 return -EINVAL; 511 512 kbuf = kzalloc(count + 1, GFP_NOFS); 513 if (!kbuf) 514 return -ENOMEM; 515 516 if (copy_from_user(kbuf, buf, count)) { 517 error = -EFAULT; 518 goto out_free; 519 } 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; 779 780 if (count == sizeof(struct dlm_device_version)) { 781 rv = copy_version_to_user(buf, count); 782 return rv; 783 } 784 785 if (!proc) { 786 log_print("non-version read from control device %zu", count); 787 return -EINVAL; 788 } 789 790 #ifdef CONFIG_COMPAT 791 if (count < sizeof(struct dlm_lock_result32)) 792 #else 793 if (count < sizeof(struct dlm_lock_result)) 794 #endif 795 return -EINVAL; 796 797 try_another: 798 799 /* do we really need this? can a read happen after a close? */ 800 if (test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags)) 801 return -EINVAL; 802 803 spin_lock(&proc->asts_spin); 804 if (list_empty(&proc->asts)) { 805 if (file->f_flags & O_NONBLOCK) { 806 spin_unlock(&proc->asts_spin); 807 return -EAGAIN; 808 } 809 810 add_wait_queue(&proc->wait, &wait); 811 812 repeat: 813 set_current_state(TASK_INTERRUPTIBLE); 814 if (list_empty(&proc->asts) && !signal_pending(current)) { 815 spin_unlock(&proc->asts_spin); 816 schedule(); 817 spin_lock(&proc->asts_spin); 818 goto repeat; 819 } 820 set_current_state(TASK_RUNNING); 821 remove_wait_queue(&proc->wait, &wait); 822 823 if (signal_pending(current)) { 824 spin_unlock(&proc->asts_spin); 825 return -ERESTARTSYS; 826 } 827 } 828 829 /* if we empty lkb_callbacks, we don't want to unlock the spinlock 830 without removing lkb_cb_list; so empty lkb_cb_list is always 831 consistent with empty lkb_callbacks */ 832 833 lkb = list_entry(proc->asts.next, struct dlm_lkb, lkb_cb_list); 834 835 rv = dlm_rem_lkb_callback(lkb->lkb_resource->res_ls, lkb, &cb, &resid); 836 if (rv < 0) { 837 /* this shouldn't happen; lkb should have been removed from 838 list when resid was zero */ 839 log_print("dlm_rem_lkb_callback empty %x", lkb->lkb_id); 840 list_del_init(&lkb->lkb_cb_list); 841 spin_unlock(&proc->asts_spin); 842 /* removes ref for proc->asts, may cause lkb to be freed */ 843 dlm_put_lkb(lkb); 844 goto try_another; 845 } 846 if (!resid) 847 list_del_init(&lkb->lkb_cb_list); 848 spin_unlock(&proc->asts_spin); 849 850 if (cb.flags & DLM_CB_SKIP) { 851 /* removes ref for proc->asts, may cause lkb to be freed */ 852 if (!resid) 853 dlm_put_lkb(lkb); 854 goto try_another; 855 } 856 857 if (cb.flags & DLM_CB_CAST) { 858 int old_mode, new_mode; 859 860 old_mode = lkb->lkb_last_cast.mode; 861 new_mode = cb.mode; 862 863 if (!cb.sb_status && lkb->lkb_lksb->sb_lvbptr && 864 dlm_lvb_operations[old_mode + 1][new_mode + 1]) 865 copy_lvb = 1; 866 867 lkb->lkb_lksb->sb_status = cb.sb_status; 868 lkb->lkb_lksb->sb_flags = cb.sb_flags; 869 } 870 871 rv = copy_result_to_user(lkb->lkb_ua, 872 test_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags), 873 cb.flags, cb.mode, copy_lvb, buf, count); 874 875 /* removes ref for proc->asts, may cause lkb to be freed */ 876 if (!resid) 877 dlm_put_lkb(lkb); 878 879 return rv; 880 } 881 882 static unsigned int device_poll(struct file *file, poll_table *wait) 883 { 884 struct dlm_user_proc *proc = file->private_data; 885 886 poll_wait(file, &proc->wait, wait); 887 888 spin_lock(&proc->asts_spin); 889 if (!list_empty(&proc->asts)) { 890 spin_unlock(&proc->asts_spin); 891 return POLLIN | POLLRDNORM; 892 } 893 spin_unlock(&proc->asts_spin); 894 return 0; 895 } 896 897 int dlm_user_daemon_available(void) 898 { 899 /* dlm_controld hasn't started (or, has started, but not 900 properly populated configfs) */ 901 902 if (!dlm_our_nodeid()) 903 return 0; 904 905 /* This is to deal with versions of dlm_controld that don't 906 know about the monitor device. We assume that if the 907 dlm_controld was started (above), but the monitor device 908 was never opened, that it's an old version. dlm_controld 909 should open the monitor device before populating configfs. */ 910 911 if (dlm_monitor_unused) 912 return 1; 913 914 return atomic_read(&dlm_monitor_opened) ? 1 : 0; 915 } 916 917 static int ctl_device_open(struct inode *inode, struct file *file) 918 { 919 file->private_data = NULL; 920 return 0; 921 } 922 923 static int ctl_device_close(struct inode *inode, struct file *file) 924 { 925 return 0; 926 } 927 928 static int monitor_device_open(struct inode *inode, struct file *file) 929 { 930 atomic_inc(&dlm_monitor_opened); 931 dlm_monitor_unused = 0; 932 return 0; 933 } 934 935 static int monitor_device_close(struct inode *inode, struct file *file) 936 { 937 if (atomic_dec_and_test(&dlm_monitor_opened)) 938 dlm_stop_lockspaces(); 939 return 0; 940 } 941 942 static const struct file_operations device_fops = { 943 .open = device_open, 944 .release = device_close, 945 .read = device_read, 946 .write = device_write, 947 .poll = device_poll, 948 .owner = THIS_MODULE, 949 .llseek = noop_llseek, 950 }; 951 952 static const struct file_operations ctl_device_fops = { 953 .open = ctl_device_open, 954 .release = ctl_device_close, 955 .read = device_read, 956 .write = device_write, 957 .owner = THIS_MODULE, 958 .llseek = noop_llseek, 959 }; 960 961 static struct miscdevice ctl_device = { 962 .name = "dlm-control", 963 .fops = &ctl_device_fops, 964 .minor = MISC_DYNAMIC_MINOR, 965 }; 966 967 static const struct file_operations monitor_device_fops = { 968 .open = monitor_device_open, 969 .release = monitor_device_close, 970 .owner = THIS_MODULE, 971 .llseek = noop_llseek, 972 }; 973 974 static struct miscdevice monitor_device = { 975 .name = "dlm-monitor", 976 .fops = &monitor_device_fops, 977 .minor = MISC_DYNAMIC_MINOR, 978 }; 979 980 int __init dlm_user_init(void) 981 { 982 int error; 983 984 atomic_set(&dlm_monitor_opened, 0); 985 986 error = misc_register(&ctl_device); 987 if (error) { 988 log_print("misc_register failed for control device"); 989 goto out; 990 } 991 992 error = misc_register(&monitor_device); 993 if (error) { 994 log_print("misc_register failed for monitor device"); 995 misc_deregister(&ctl_device); 996 } 997 out: 998 return error; 999 } 1000 1001 void dlm_user_exit(void) 1002 { 1003 misc_deregister(&ctl_device); 1004 misc_deregister(&monitor_device); 1005 } 1006 1007