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 uint32_t lkid; 242 int error = -ENOMEM; 243 244 ls = dlm_find_lockspace_local(proc->lockspace); 245 if (!ls) 246 return -ENOENT; 247 248 if (!params->castaddr || !params->lksb) { 249 error = -EINVAL; 250 goto out; 251 } 252 253 ua = kzalloc(sizeof(struct dlm_user_args), GFP_NOFS); 254 if (!ua) 255 goto out; 256 ua->proc = proc; 257 ua->user_lksb = params->lksb; 258 ua->castparam = params->castparam; 259 ua->castaddr = params->castaddr; 260 ua->bastparam = params->bastparam; 261 ua->bastaddr = params->bastaddr; 262 ua->xid = params->xid; 263 264 if (params->flags & DLM_LKF_CONVERT) { 265 error = dlm_user_convert(ls, ua, 266 params->mode, params->flags, 267 params->lkid, params->lvb, 268 (unsigned long) params->timeout); 269 } else if (params->flags & DLM_LKF_ORPHAN) { 270 error = dlm_user_adopt_orphan(ls, ua, 271 params->mode, params->flags, 272 params->name, params->namelen, 273 (unsigned long) params->timeout, 274 &lkid); 275 if (!error) 276 error = lkid; 277 } else { 278 error = dlm_user_request(ls, ua, 279 params->mode, params->flags, 280 params->name, params->namelen, 281 (unsigned long) params->timeout); 282 if (!error) 283 error = ua->lksb.sb_lkid; 284 } 285 out: 286 dlm_put_lockspace(ls); 287 return error; 288 } 289 290 static int device_user_unlock(struct dlm_user_proc *proc, 291 struct dlm_lock_params *params) 292 { 293 struct dlm_ls *ls; 294 struct dlm_user_args *ua; 295 int error = -ENOMEM; 296 297 ls = dlm_find_lockspace_local(proc->lockspace); 298 if (!ls) 299 return -ENOENT; 300 301 ua = kzalloc(sizeof(struct dlm_user_args), GFP_NOFS); 302 if (!ua) 303 goto out; 304 ua->proc = proc; 305 ua->user_lksb = params->lksb; 306 ua->castparam = params->castparam; 307 ua->castaddr = params->castaddr; 308 309 if (params->flags & DLM_LKF_CANCEL) 310 error = dlm_user_cancel(ls, ua, params->flags, params->lkid); 311 else 312 error = dlm_user_unlock(ls, ua, params->flags, params->lkid, 313 params->lvb); 314 out: 315 dlm_put_lockspace(ls); 316 return error; 317 } 318 319 static int device_user_deadlock(struct dlm_user_proc *proc, 320 struct dlm_lock_params *params) 321 { 322 struct dlm_ls *ls; 323 int error; 324 325 ls = dlm_find_lockspace_local(proc->lockspace); 326 if (!ls) 327 return -ENOENT; 328 329 error = dlm_user_deadlock(ls, params->flags, params->lkid); 330 331 dlm_put_lockspace(ls); 332 return error; 333 } 334 335 static int dlm_device_register(struct dlm_ls *ls, char *name) 336 { 337 int error, len; 338 339 /* The device is already registered. This happens when the 340 lockspace is created multiple times from userspace. */ 341 if (ls->ls_device.name) 342 return 0; 343 344 error = -ENOMEM; 345 len = strlen(name) + strlen(name_prefix) + 2; 346 ls->ls_device.name = kzalloc(len, GFP_NOFS); 347 if (!ls->ls_device.name) 348 goto fail; 349 350 snprintf((char *)ls->ls_device.name, len, "%s_%s", name_prefix, 351 name); 352 ls->ls_device.fops = &device_fops; 353 ls->ls_device.minor = MISC_DYNAMIC_MINOR; 354 355 error = misc_register(&ls->ls_device); 356 if (error) { 357 kfree(ls->ls_device.name); 358 } 359 fail: 360 return error; 361 } 362 363 int dlm_device_deregister(struct dlm_ls *ls) 364 { 365 int error; 366 367 /* The device is not registered. This happens when the lockspace 368 was never used from userspace, or when device_create_lockspace() 369 calls dlm_release_lockspace() after the register fails. */ 370 if (!ls->ls_device.name) 371 return 0; 372 373 error = misc_deregister(&ls->ls_device); 374 if (!error) 375 kfree(ls->ls_device.name); 376 return error; 377 } 378 379 static int device_user_purge(struct dlm_user_proc *proc, 380 struct dlm_purge_params *params) 381 { 382 struct dlm_ls *ls; 383 int error; 384 385 ls = dlm_find_lockspace_local(proc->lockspace); 386 if (!ls) 387 return -ENOENT; 388 389 error = dlm_user_purge(ls, proc, params->nodeid, params->pid); 390 391 dlm_put_lockspace(ls); 392 return error; 393 } 394 395 static int device_create_lockspace(struct dlm_lspace_params *params) 396 { 397 dlm_lockspace_t *lockspace; 398 struct dlm_ls *ls; 399 int error; 400 401 if (!capable(CAP_SYS_ADMIN)) 402 return -EPERM; 403 404 error = dlm_new_lockspace(params->name, NULL, params->flags, 405 DLM_USER_LVB_LEN, NULL, NULL, NULL, 406 &lockspace); 407 if (error) 408 return error; 409 410 ls = dlm_find_lockspace_local(lockspace); 411 if (!ls) 412 return -ENOENT; 413 414 error = dlm_device_register(ls, params->name); 415 dlm_put_lockspace(ls); 416 417 if (error) 418 dlm_release_lockspace(lockspace, 0); 419 else 420 error = ls->ls_device.minor; 421 422 return error; 423 } 424 425 static int device_remove_lockspace(struct dlm_lspace_params *params) 426 { 427 dlm_lockspace_t *lockspace; 428 struct dlm_ls *ls; 429 int error, force = 0; 430 431 if (!capable(CAP_SYS_ADMIN)) 432 return -EPERM; 433 434 ls = dlm_find_lockspace_device(params->minor); 435 if (!ls) 436 return -ENOENT; 437 438 if (params->flags & DLM_USER_LSFLG_FORCEFREE) 439 force = 2; 440 441 lockspace = ls->ls_local_handle; 442 dlm_put_lockspace(ls); 443 444 /* The final dlm_release_lockspace waits for references to go to 445 zero, so all processes will need to close their device for the 446 ls before the release will proceed. release also calls the 447 device_deregister above. Converting a positive return value 448 from release to zero means that userspace won't know when its 449 release was the final one, but it shouldn't need to know. */ 450 451 error = dlm_release_lockspace(lockspace, force); 452 if (error > 0) 453 error = 0; 454 return error; 455 } 456 457 /* Check the user's version matches ours */ 458 static int check_version(struct dlm_write_request *req) 459 { 460 if (req->version[0] != DLM_DEVICE_VERSION_MAJOR || 461 (req->version[0] == DLM_DEVICE_VERSION_MAJOR && 462 req->version[1] > DLM_DEVICE_VERSION_MINOR)) { 463 464 printk(KERN_DEBUG "dlm: process %s (%d) version mismatch " 465 "user (%d.%d.%d) kernel (%d.%d.%d)\n", 466 current->comm, 467 task_pid_nr(current), 468 req->version[0], 469 req->version[1], 470 req->version[2], 471 DLM_DEVICE_VERSION_MAJOR, 472 DLM_DEVICE_VERSION_MINOR, 473 DLM_DEVICE_VERSION_PATCH); 474 return -EINVAL; 475 } 476 return 0; 477 } 478 479 /* 480 * device_write 481 * 482 * device_user_lock 483 * dlm_user_request -> request_lock 484 * dlm_user_convert -> convert_lock 485 * 486 * device_user_unlock 487 * dlm_user_unlock -> unlock_lock 488 * dlm_user_cancel -> cancel_lock 489 * 490 * device_create_lockspace 491 * dlm_new_lockspace 492 * 493 * device_remove_lockspace 494 * dlm_release_lockspace 495 */ 496 497 /* a write to a lockspace device is a lock or unlock request, a write 498 to the control device is to create/remove a lockspace */ 499 500 static ssize_t device_write(struct file *file, const char __user *buf, 501 size_t count, loff_t *ppos) 502 { 503 struct dlm_user_proc *proc = file->private_data; 504 struct dlm_write_request *kbuf; 505 int error; 506 507 #ifdef CONFIG_COMPAT 508 if (count < sizeof(struct dlm_write_request32)) 509 #else 510 if (count < sizeof(struct dlm_write_request)) 511 #endif 512 return -EINVAL; 513 514 /* 515 * can't compare against COMPAT/dlm_write_request32 because 516 * we don't yet know if is64bit is zero 517 */ 518 if (count > sizeof(struct dlm_write_request) + DLM_RESNAME_MAXLEN) 519 return -EINVAL; 520 521 kbuf = kzalloc(count + 1, GFP_NOFS); 522 if (!kbuf) 523 return -ENOMEM; 524 525 if (copy_from_user(kbuf, buf, count)) { 526 error = -EFAULT; 527 goto out_free; 528 } 529 530 if (check_version(kbuf)) { 531 error = -EBADE; 532 goto out_free; 533 } 534 535 #ifdef CONFIG_COMPAT 536 if (!kbuf->is64bit) { 537 struct dlm_write_request32 *k32buf; 538 int namelen = 0; 539 540 if (count > sizeof(struct dlm_write_request32)) 541 namelen = count - sizeof(struct dlm_write_request32); 542 543 k32buf = (struct dlm_write_request32 *)kbuf; 544 545 /* add 1 after namelen so that the name string is terminated */ 546 kbuf = kzalloc(sizeof(struct dlm_write_request) + namelen + 1, 547 GFP_NOFS); 548 if (!kbuf) { 549 kfree(k32buf); 550 return -ENOMEM; 551 } 552 553 if (proc) 554 set_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags); 555 556 compat_input(kbuf, k32buf, namelen); 557 kfree(k32buf); 558 } 559 #endif 560 561 /* do we really need this? can a write happen after a close? */ 562 if ((kbuf->cmd == DLM_USER_LOCK || kbuf->cmd == DLM_USER_UNLOCK) && 563 (proc && test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))) { 564 error = -EINVAL; 565 goto out_free; 566 } 567 568 error = -EINVAL; 569 570 switch (kbuf->cmd) 571 { 572 case DLM_USER_LOCK: 573 if (!proc) { 574 log_print("no locking on control device"); 575 goto out_free; 576 } 577 error = device_user_lock(proc, &kbuf->i.lock); 578 break; 579 580 case DLM_USER_UNLOCK: 581 if (!proc) { 582 log_print("no locking on control device"); 583 goto out_free; 584 } 585 error = device_user_unlock(proc, &kbuf->i.lock); 586 break; 587 588 case DLM_USER_DEADLOCK: 589 if (!proc) { 590 log_print("no locking on control device"); 591 goto out_free; 592 } 593 error = device_user_deadlock(proc, &kbuf->i.lock); 594 break; 595 596 case DLM_USER_CREATE_LOCKSPACE: 597 if (proc) { 598 log_print("create/remove only on control device"); 599 goto out_free; 600 } 601 error = device_create_lockspace(&kbuf->i.lspace); 602 break; 603 604 case DLM_USER_REMOVE_LOCKSPACE: 605 if (proc) { 606 log_print("create/remove only on control device"); 607 goto out_free; 608 } 609 error = device_remove_lockspace(&kbuf->i.lspace); 610 break; 611 612 case DLM_USER_PURGE: 613 if (!proc) { 614 log_print("no locking on control device"); 615 goto out_free; 616 } 617 error = device_user_purge(proc, &kbuf->i.purge); 618 break; 619 620 default: 621 log_print("Unknown command passed to DLM device : %d\n", 622 kbuf->cmd); 623 } 624 625 out_free: 626 kfree(kbuf); 627 return error; 628 } 629 630 /* Every process that opens the lockspace device has its own "proc" structure 631 hanging off the open file that's used to keep track of locks owned by the 632 process and asts that need to be delivered to the process. */ 633 634 static int device_open(struct inode *inode, struct file *file) 635 { 636 struct dlm_user_proc *proc; 637 struct dlm_ls *ls; 638 639 ls = dlm_find_lockspace_device(iminor(inode)); 640 if (!ls) 641 return -ENOENT; 642 643 proc = kzalloc(sizeof(struct dlm_user_proc), GFP_NOFS); 644 if (!proc) { 645 dlm_put_lockspace(ls); 646 return -ENOMEM; 647 } 648 649 proc->lockspace = ls->ls_local_handle; 650 INIT_LIST_HEAD(&proc->asts); 651 INIT_LIST_HEAD(&proc->locks); 652 INIT_LIST_HEAD(&proc->unlocking); 653 spin_lock_init(&proc->asts_spin); 654 spin_lock_init(&proc->locks_spin); 655 init_waitqueue_head(&proc->wait); 656 file->private_data = proc; 657 658 return 0; 659 } 660 661 static int device_close(struct inode *inode, struct file *file) 662 { 663 struct dlm_user_proc *proc = file->private_data; 664 struct dlm_ls *ls; 665 666 ls = dlm_find_lockspace_local(proc->lockspace); 667 if (!ls) 668 return -ENOENT; 669 670 set_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags); 671 672 dlm_clear_proc_locks(ls, proc); 673 674 /* at this point no more lkb's should exist for this lockspace, 675 so there's no chance of dlm_user_add_ast() being called and 676 looking for lkb->ua->proc */ 677 678 kfree(proc); 679 file->private_data = NULL; 680 681 dlm_put_lockspace(ls); 682 dlm_put_lockspace(ls); /* for the find in device_open() */ 683 684 /* FIXME: AUTOFREE: if this ls is no longer used do 685 device_remove_lockspace() */ 686 687 return 0; 688 } 689 690 static int copy_result_to_user(struct dlm_user_args *ua, int compat, 691 uint32_t flags, int mode, int copy_lvb, 692 char __user *buf, size_t count) 693 { 694 #ifdef CONFIG_COMPAT 695 struct dlm_lock_result32 result32; 696 #endif 697 struct dlm_lock_result result; 698 void *resultptr; 699 int error=0; 700 int len; 701 int struct_len; 702 703 memset(&result, 0, sizeof(struct dlm_lock_result)); 704 result.version[0] = DLM_DEVICE_VERSION_MAJOR; 705 result.version[1] = DLM_DEVICE_VERSION_MINOR; 706 result.version[2] = DLM_DEVICE_VERSION_PATCH; 707 memcpy(&result.lksb, &ua->lksb, sizeof(struct dlm_lksb)); 708 result.user_lksb = ua->user_lksb; 709 710 /* FIXME: dlm1 provides for the user's bastparam/addr to not be updated 711 in a conversion unless the conversion is successful. See code 712 in dlm_user_convert() for updating ua from ua_tmp. OpenVMS, though, 713 notes that a new blocking AST address and parameter are set even if 714 the conversion fails, so maybe we should just do that. */ 715 716 if (flags & DLM_CB_BAST) { 717 result.user_astaddr = ua->bastaddr; 718 result.user_astparam = ua->bastparam; 719 result.bast_mode = mode; 720 } else { 721 result.user_astaddr = ua->castaddr; 722 result.user_astparam = ua->castparam; 723 } 724 725 #ifdef CONFIG_COMPAT 726 if (compat) 727 len = sizeof(struct dlm_lock_result32); 728 else 729 #endif 730 len = sizeof(struct dlm_lock_result); 731 struct_len = len; 732 733 /* copy lvb to userspace if there is one, it's been updated, and 734 the user buffer has space for it */ 735 736 if (copy_lvb && ua->lksb.sb_lvbptr && count >= len + DLM_USER_LVB_LEN) { 737 if (copy_to_user(buf+len, ua->lksb.sb_lvbptr, 738 DLM_USER_LVB_LEN)) { 739 error = -EFAULT; 740 goto out; 741 } 742 743 result.lvb_offset = len; 744 len += DLM_USER_LVB_LEN; 745 } 746 747 result.length = len; 748 resultptr = &result; 749 #ifdef CONFIG_COMPAT 750 if (compat) { 751 compat_output(&result, &result32); 752 resultptr = &result32; 753 } 754 #endif 755 756 if (copy_to_user(buf, resultptr, struct_len)) 757 error = -EFAULT; 758 else 759 error = len; 760 out: 761 return error; 762 } 763 764 static int copy_version_to_user(char __user *buf, size_t count) 765 { 766 struct dlm_device_version ver; 767 768 memset(&ver, 0, sizeof(struct dlm_device_version)); 769 ver.version[0] = DLM_DEVICE_VERSION_MAJOR; 770 ver.version[1] = DLM_DEVICE_VERSION_MINOR; 771 ver.version[2] = DLM_DEVICE_VERSION_PATCH; 772 773 if (copy_to_user(buf, &ver, sizeof(struct dlm_device_version))) 774 return -EFAULT; 775 return sizeof(struct dlm_device_version); 776 } 777 778 /* a read returns a single ast described in a struct dlm_lock_result */ 779 780 static ssize_t device_read(struct file *file, char __user *buf, size_t count, 781 loff_t *ppos) 782 { 783 struct dlm_user_proc *proc = file->private_data; 784 struct dlm_lkb *lkb; 785 DECLARE_WAITQUEUE(wait, current); 786 struct dlm_callback cb; 787 int rv, resid, copy_lvb = 0; 788 789 if (count == sizeof(struct dlm_device_version)) { 790 rv = copy_version_to_user(buf, count); 791 return rv; 792 } 793 794 if (!proc) { 795 log_print("non-version read from control device %zu", count); 796 return -EINVAL; 797 } 798 799 #ifdef CONFIG_COMPAT 800 if (count < sizeof(struct dlm_lock_result32)) 801 #else 802 if (count < sizeof(struct dlm_lock_result)) 803 #endif 804 return -EINVAL; 805 806 try_another: 807 808 /* do we really need this? can a read happen after a close? */ 809 if (test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags)) 810 return -EINVAL; 811 812 spin_lock(&proc->asts_spin); 813 if (list_empty(&proc->asts)) { 814 if (file->f_flags & O_NONBLOCK) { 815 spin_unlock(&proc->asts_spin); 816 return -EAGAIN; 817 } 818 819 add_wait_queue(&proc->wait, &wait); 820 821 repeat: 822 set_current_state(TASK_INTERRUPTIBLE); 823 if (list_empty(&proc->asts) && !signal_pending(current)) { 824 spin_unlock(&proc->asts_spin); 825 schedule(); 826 spin_lock(&proc->asts_spin); 827 goto repeat; 828 } 829 set_current_state(TASK_RUNNING); 830 remove_wait_queue(&proc->wait, &wait); 831 832 if (signal_pending(current)) { 833 spin_unlock(&proc->asts_spin); 834 return -ERESTARTSYS; 835 } 836 } 837 838 /* if we empty lkb_callbacks, we don't want to unlock the spinlock 839 without removing lkb_cb_list; so empty lkb_cb_list is always 840 consistent with empty lkb_callbacks */ 841 842 lkb = list_entry(proc->asts.next, struct dlm_lkb, lkb_cb_list); 843 844 rv = dlm_rem_lkb_callback(lkb->lkb_resource->res_ls, lkb, &cb, &resid); 845 if (rv < 0) { 846 /* this shouldn't happen; lkb should have been removed from 847 list when resid was zero */ 848 log_print("dlm_rem_lkb_callback empty %x", lkb->lkb_id); 849 list_del_init(&lkb->lkb_cb_list); 850 spin_unlock(&proc->asts_spin); 851 /* removes ref for proc->asts, may cause lkb to be freed */ 852 dlm_put_lkb(lkb); 853 goto try_another; 854 } 855 if (!resid) 856 list_del_init(&lkb->lkb_cb_list); 857 spin_unlock(&proc->asts_spin); 858 859 if (cb.flags & DLM_CB_SKIP) { 860 /* removes ref for proc->asts, may cause lkb to be freed */ 861 if (!resid) 862 dlm_put_lkb(lkb); 863 goto try_another; 864 } 865 866 if (cb.flags & DLM_CB_CAST) { 867 int old_mode, new_mode; 868 869 old_mode = lkb->lkb_last_cast.mode; 870 new_mode = cb.mode; 871 872 if (!cb.sb_status && lkb->lkb_lksb->sb_lvbptr && 873 dlm_lvb_operations[old_mode + 1][new_mode + 1]) 874 copy_lvb = 1; 875 876 lkb->lkb_lksb->sb_status = cb.sb_status; 877 lkb->lkb_lksb->sb_flags = cb.sb_flags; 878 } 879 880 rv = copy_result_to_user(lkb->lkb_ua, 881 test_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags), 882 cb.flags, cb.mode, copy_lvb, buf, count); 883 884 /* removes ref for proc->asts, may cause lkb to be freed */ 885 if (!resid) 886 dlm_put_lkb(lkb); 887 888 return rv; 889 } 890 891 static unsigned int device_poll(struct file *file, poll_table *wait) 892 { 893 struct dlm_user_proc *proc = file->private_data; 894 895 poll_wait(file, &proc->wait, wait); 896 897 spin_lock(&proc->asts_spin); 898 if (!list_empty(&proc->asts)) { 899 spin_unlock(&proc->asts_spin); 900 return POLLIN | POLLRDNORM; 901 } 902 spin_unlock(&proc->asts_spin); 903 return 0; 904 } 905 906 int dlm_user_daemon_available(void) 907 { 908 /* dlm_controld hasn't started (or, has started, but not 909 properly populated configfs) */ 910 911 if (!dlm_our_nodeid()) 912 return 0; 913 914 /* This is to deal with versions of dlm_controld that don't 915 know about the monitor device. We assume that if the 916 dlm_controld was started (above), but the monitor device 917 was never opened, that it's an old version. dlm_controld 918 should open the monitor device before populating configfs. */ 919 920 if (dlm_monitor_unused) 921 return 1; 922 923 return atomic_read(&dlm_monitor_opened) ? 1 : 0; 924 } 925 926 static int ctl_device_open(struct inode *inode, struct file *file) 927 { 928 file->private_data = NULL; 929 return 0; 930 } 931 932 static int ctl_device_close(struct inode *inode, struct file *file) 933 { 934 return 0; 935 } 936 937 static int monitor_device_open(struct inode *inode, struct file *file) 938 { 939 atomic_inc(&dlm_monitor_opened); 940 dlm_monitor_unused = 0; 941 return 0; 942 } 943 944 static int monitor_device_close(struct inode *inode, struct file *file) 945 { 946 if (atomic_dec_and_test(&dlm_monitor_opened)) 947 dlm_stop_lockspaces(); 948 return 0; 949 } 950 951 static const struct file_operations device_fops = { 952 .open = device_open, 953 .release = device_close, 954 .read = device_read, 955 .write = device_write, 956 .poll = device_poll, 957 .owner = THIS_MODULE, 958 .llseek = noop_llseek, 959 }; 960 961 static const struct file_operations ctl_device_fops = { 962 .open = ctl_device_open, 963 .release = ctl_device_close, 964 .read = device_read, 965 .write = device_write, 966 .owner = THIS_MODULE, 967 .llseek = noop_llseek, 968 }; 969 970 static struct miscdevice ctl_device = { 971 .name = "dlm-control", 972 .fops = &ctl_device_fops, 973 .minor = MISC_DYNAMIC_MINOR, 974 }; 975 976 static const struct file_operations monitor_device_fops = { 977 .open = monitor_device_open, 978 .release = monitor_device_close, 979 .owner = THIS_MODULE, 980 .llseek = noop_llseek, 981 }; 982 983 static struct miscdevice monitor_device = { 984 .name = "dlm-monitor", 985 .fops = &monitor_device_fops, 986 .minor = MISC_DYNAMIC_MINOR, 987 }; 988 989 int __init dlm_user_init(void) 990 { 991 int error; 992 993 atomic_set(&dlm_monitor_opened, 0); 994 995 error = misc_register(&ctl_device); 996 if (error) { 997 log_print("misc_register failed for control device"); 998 goto out; 999 } 1000 1001 error = misc_register(&monitor_device); 1002 if (error) { 1003 log_print("misc_register failed for monitor device"); 1004 misc_deregister(&ctl_device); 1005 } 1006 out: 1007 return error; 1008 } 1009 1010 void dlm_user_exit(void) 1011 { 1012 misc_deregister(&ctl_device); 1013 misc_deregister(&monitor_device); 1014 } 1015 1016