1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (C) 2006-2010 Red Hat, Inc. All rights reserved. 4 */ 5 6 #include <linux/miscdevice.h> 7 #include <linux/init.h> 8 #include <linux/wait.h> 9 #include <linux/file.h> 10 #include <linux/fs.h> 11 #include <linux/poll.h> 12 #include <linux/signal.h> 13 #include <linux/spinlock.h> 14 #include <linux/dlm.h> 15 #include <linux/dlm_device.h> 16 #include <linux/slab.h> 17 #include <linux/sched/signal.h> 18 19 #include "dlm_internal.h" 20 #include "lockspace.h" 21 #include "lock.h" 22 #include "lvb_table.h" 23 #include "user.h" 24 #include "ast.h" 25 #include "config.h" 26 27 static const char name_prefix[] = "dlm"; 28 static const struct file_operations device_fops; 29 static atomic_t dlm_monitor_opened; 30 static int dlm_monitor_unused = 1; 31 32 #ifdef CONFIG_COMPAT 33 34 struct dlm_lock_params32 { 35 __u8 mode; 36 __u8 namelen; 37 __u16 unused; 38 __u32 flags; 39 __u32 lkid; 40 __u32 parent; 41 __u64 xid; 42 __u64 timeout; 43 __u32 castparam; 44 __u32 castaddr; 45 __u32 bastparam; 46 __u32 bastaddr; 47 __u32 lksb; 48 char lvb[DLM_USER_LVB_LEN]; 49 char name[]; 50 }; 51 52 struct dlm_write_request32 { 53 __u32 version[3]; 54 __u8 cmd; 55 __u8 is64bit; 56 __u8 unused[2]; 57 58 union { 59 struct dlm_lock_params32 lock; 60 struct dlm_lspace_params lspace; 61 struct dlm_purge_params purge; 62 } i; 63 }; 64 65 struct dlm_lksb32 { 66 __u32 sb_status; 67 __u32 sb_lkid; 68 __u8 sb_flags; 69 __u32 sb_lvbptr; 70 }; 71 72 struct dlm_lock_result32 { 73 __u32 version[3]; 74 __u32 length; 75 __u32 user_astaddr; 76 __u32 user_astparam; 77 __u32 user_lksb; 78 struct dlm_lksb32 lksb; 79 __u8 bast_mode; 80 __u8 unused[3]; 81 /* Offsets may be zero if no data is present */ 82 __u32 lvb_offset; 83 }; 84 85 static void compat_input(struct dlm_write_request *kb, 86 struct dlm_write_request32 *kb32, 87 int namelen) 88 { 89 kb->version[0] = kb32->version[0]; 90 kb->version[1] = kb32->version[1]; 91 kb->version[2] = kb32->version[2]; 92 93 kb->cmd = kb32->cmd; 94 kb->is64bit = kb32->is64bit; 95 if (kb->cmd == DLM_USER_CREATE_LOCKSPACE || 96 kb->cmd == DLM_USER_REMOVE_LOCKSPACE) { 97 kb->i.lspace.flags = kb32->i.lspace.flags; 98 kb->i.lspace.minor = kb32->i.lspace.minor; 99 memcpy(kb->i.lspace.name, kb32->i.lspace.name, namelen); 100 } else if (kb->cmd == DLM_USER_PURGE) { 101 kb->i.purge.nodeid = kb32->i.purge.nodeid; 102 kb->i.purge.pid = kb32->i.purge.pid; 103 } else { 104 kb->i.lock.mode = kb32->i.lock.mode; 105 kb->i.lock.namelen = kb32->i.lock.namelen; 106 kb->i.lock.flags = kb32->i.lock.flags; 107 kb->i.lock.lkid = kb32->i.lock.lkid; 108 kb->i.lock.parent = kb32->i.lock.parent; 109 kb->i.lock.xid = kb32->i.lock.xid; 110 kb->i.lock.timeout = kb32->i.lock.timeout; 111 kb->i.lock.castparam = (void *)(long)kb32->i.lock.castparam; 112 kb->i.lock.castaddr = (void *)(long)kb32->i.lock.castaddr; 113 kb->i.lock.bastparam = (void *)(long)kb32->i.lock.bastparam; 114 kb->i.lock.bastaddr = (void *)(long)kb32->i.lock.bastaddr; 115 kb->i.lock.lksb = (void *)(long)kb32->i.lock.lksb; 116 memcpy(kb->i.lock.lvb, kb32->i.lock.lvb, DLM_USER_LVB_LEN); 117 memcpy(kb->i.lock.name, kb32->i.lock.name, namelen); 118 } 119 } 120 121 static void compat_output(struct dlm_lock_result *res, 122 struct dlm_lock_result32 *res32) 123 { 124 memset(res32, 0, sizeof(*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 /* this has to be set to NULL 359 * to avoid a double-free in dlm_device_deregister 360 */ 361 ls->ls_device.name = NULL; 362 } 363 fail: 364 return error; 365 } 366 367 int dlm_device_deregister(struct dlm_ls *ls) 368 { 369 /* The device is not registered. This happens when the lockspace 370 was never used from userspace, or when device_create_lockspace() 371 calls dlm_release_lockspace() after the register fails. */ 372 if (!ls->ls_device.name) 373 return 0; 374 375 misc_deregister(&ls->ls_device); 376 kfree(ls->ls_device.name); 377 return 0; 378 } 379 380 static int device_user_purge(struct dlm_user_proc *proc, 381 struct dlm_purge_params *params) 382 { 383 struct dlm_ls *ls; 384 int error; 385 386 ls = dlm_find_lockspace_local(proc->lockspace); 387 if (!ls) 388 return -ENOENT; 389 390 error = dlm_user_purge(ls, proc, params->nodeid, params->pid); 391 392 dlm_put_lockspace(ls); 393 return error; 394 } 395 396 static int device_create_lockspace(struct dlm_lspace_params *params) 397 { 398 dlm_lockspace_t *lockspace; 399 struct dlm_ls *ls; 400 int error; 401 402 if (!capable(CAP_SYS_ADMIN)) 403 return -EPERM; 404 405 error = dlm_new_lockspace(params->name, dlm_config.ci_cluster_name, params->flags, 406 DLM_USER_LVB_LEN, NULL, NULL, NULL, 407 &lockspace); 408 if (error) 409 return error; 410 411 ls = dlm_find_lockspace_local(lockspace); 412 if (!ls) 413 return -ENOENT; 414 415 error = dlm_device_register(ls, params->name); 416 dlm_put_lockspace(ls); 417 418 if (error) 419 dlm_release_lockspace(lockspace, 0); 420 else 421 error = ls->ls_device.minor; 422 423 return error; 424 } 425 426 static int device_remove_lockspace(struct dlm_lspace_params *params) 427 { 428 dlm_lockspace_t *lockspace; 429 struct dlm_ls *ls; 430 int error, force = 0; 431 432 if (!capable(CAP_SYS_ADMIN)) 433 return -EPERM; 434 435 ls = dlm_find_lockspace_device(params->minor); 436 if (!ls) 437 return -ENOENT; 438 439 if (params->flags & DLM_USER_LSFLG_FORCEFREE) 440 force = 2; 441 442 lockspace = ls->ls_local_handle; 443 dlm_put_lockspace(ls); 444 445 /* The final dlm_release_lockspace waits for references to go to 446 zero, so all processes will need to close their device for the 447 ls before the release will proceed. release also calls the 448 device_deregister above. Converting a positive return value 449 from release to zero means that userspace won't know when its 450 release was the final one, but it shouldn't need to know. */ 451 452 error = dlm_release_lockspace(lockspace, force); 453 if (error > 0) 454 error = 0; 455 return error; 456 } 457 458 /* Check the user's version matches ours */ 459 static int check_version(struct dlm_write_request *req) 460 { 461 if (req->version[0] != DLM_DEVICE_VERSION_MAJOR || 462 (req->version[0] == DLM_DEVICE_VERSION_MAJOR && 463 req->version[1] > DLM_DEVICE_VERSION_MINOR)) { 464 465 printk(KERN_DEBUG "dlm: process %s (%d) version mismatch " 466 "user (%d.%d.%d) kernel (%d.%d.%d)\n", 467 current->comm, 468 task_pid_nr(current), 469 req->version[0], 470 req->version[1], 471 req->version[2], 472 DLM_DEVICE_VERSION_MAJOR, 473 DLM_DEVICE_VERSION_MINOR, 474 DLM_DEVICE_VERSION_PATCH); 475 return -EINVAL; 476 } 477 return 0; 478 } 479 480 /* 481 * device_write 482 * 483 * device_user_lock 484 * dlm_user_request -> request_lock 485 * dlm_user_convert -> convert_lock 486 * 487 * device_user_unlock 488 * dlm_user_unlock -> unlock_lock 489 * dlm_user_cancel -> cancel_lock 490 * 491 * device_create_lockspace 492 * dlm_new_lockspace 493 * 494 * device_remove_lockspace 495 * dlm_release_lockspace 496 */ 497 498 /* a write to a lockspace device is a lock or unlock request, a write 499 to the control device is to create/remove a lockspace */ 500 501 static ssize_t device_write(struct file *file, const char __user *buf, 502 size_t count, loff_t *ppos) 503 { 504 struct dlm_user_proc *proc = file->private_data; 505 struct dlm_write_request *kbuf; 506 int error; 507 508 #ifdef CONFIG_COMPAT 509 if (count < sizeof(struct dlm_write_request32)) 510 #else 511 if (count < sizeof(struct dlm_write_request)) 512 #endif 513 return -EINVAL; 514 515 /* 516 * can't compare against COMPAT/dlm_write_request32 because 517 * we don't yet know if is64bit is zero 518 */ 519 if (count > sizeof(struct dlm_write_request) + DLM_RESNAME_MAXLEN) 520 return -EINVAL; 521 522 kbuf = memdup_user_nul(buf, count); 523 if (IS_ERR(kbuf)) 524 return PTR_ERR(kbuf); 525 526 if (check_version(kbuf)) { 527 error = -EBADE; 528 goto out_free; 529 } 530 531 #ifdef CONFIG_COMPAT 532 if (!kbuf->is64bit) { 533 struct dlm_write_request32 *k32buf; 534 int namelen = 0; 535 536 if (count > sizeof(struct dlm_write_request32)) 537 namelen = count - sizeof(struct dlm_write_request32); 538 539 k32buf = (struct dlm_write_request32 *)kbuf; 540 541 /* add 1 after namelen so that the name string is terminated */ 542 kbuf = kzalloc(sizeof(struct dlm_write_request) + namelen + 1, 543 GFP_NOFS); 544 if (!kbuf) { 545 kfree(k32buf); 546 return -ENOMEM; 547 } 548 549 if (proc) 550 set_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags); 551 552 compat_input(kbuf, k32buf, namelen); 553 kfree(k32buf); 554 } 555 #endif 556 557 /* do we really need this? can a write happen after a close? */ 558 if ((kbuf->cmd == DLM_USER_LOCK || kbuf->cmd == DLM_USER_UNLOCK) && 559 (proc && test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))) { 560 error = -EINVAL; 561 goto out_free; 562 } 563 564 error = -EINVAL; 565 566 switch (kbuf->cmd) 567 { 568 case DLM_USER_LOCK: 569 if (!proc) { 570 log_print("no locking on control device"); 571 goto out_free; 572 } 573 error = device_user_lock(proc, &kbuf->i.lock); 574 break; 575 576 case DLM_USER_UNLOCK: 577 if (!proc) { 578 log_print("no locking on control device"); 579 goto out_free; 580 } 581 error = device_user_unlock(proc, &kbuf->i.lock); 582 break; 583 584 case DLM_USER_DEADLOCK: 585 if (!proc) { 586 log_print("no locking on control device"); 587 goto out_free; 588 } 589 error = device_user_deadlock(proc, &kbuf->i.lock); 590 break; 591 592 case DLM_USER_CREATE_LOCKSPACE: 593 if (proc) { 594 log_print("create/remove only on control device"); 595 goto out_free; 596 } 597 error = device_create_lockspace(&kbuf->i.lspace); 598 break; 599 600 case DLM_USER_REMOVE_LOCKSPACE: 601 if (proc) { 602 log_print("create/remove only on control device"); 603 goto out_free; 604 } 605 error = device_remove_lockspace(&kbuf->i.lspace); 606 break; 607 608 case DLM_USER_PURGE: 609 if (!proc) { 610 log_print("no locking on control device"); 611 goto out_free; 612 } 613 error = device_user_purge(proc, &kbuf->i.purge); 614 break; 615 616 default: 617 log_print("Unknown command passed to DLM device : %d\n", 618 kbuf->cmd); 619 } 620 621 out_free: 622 kfree(kbuf); 623 return error; 624 } 625 626 /* Every process that opens the lockspace device has its own "proc" structure 627 hanging off the open file that's used to keep track of locks owned by the 628 process and asts that need to be delivered to the process. */ 629 630 static int device_open(struct inode *inode, struct file *file) 631 { 632 struct dlm_user_proc *proc; 633 struct dlm_ls *ls; 634 635 ls = dlm_find_lockspace_device(iminor(inode)); 636 if (!ls) 637 return -ENOENT; 638 639 proc = kzalloc(sizeof(struct dlm_user_proc), GFP_NOFS); 640 if (!proc) { 641 dlm_put_lockspace(ls); 642 return -ENOMEM; 643 } 644 645 proc->lockspace = ls->ls_local_handle; 646 INIT_LIST_HEAD(&proc->asts); 647 INIT_LIST_HEAD(&proc->locks); 648 INIT_LIST_HEAD(&proc->unlocking); 649 spin_lock_init(&proc->asts_spin); 650 spin_lock_init(&proc->locks_spin); 651 init_waitqueue_head(&proc->wait); 652 file->private_data = proc; 653 654 return 0; 655 } 656 657 static int device_close(struct inode *inode, struct file *file) 658 { 659 struct dlm_user_proc *proc = file->private_data; 660 struct dlm_ls *ls; 661 662 ls = dlm_find_lockspace_local(proc->lockspace); 663 if (!ls) 664 return -ENOENT; 665 666 set_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags); 667 668 dlm_clear_proc_locks(ls, proc); 669 670 /* at this point no more lkb's should exist for this lockspace, 671 so there's no chance of dlm_user_add_ast() being called and 672 looking for lkb->ua->proc */ 673 674 kfree(proc); 675 file->private_data = NULL; 676 677 dlm_put_lockspace(ls); 678 dlm_put_lockspace(ls); /* for the find in device_open() */ 679 680 /* FIXME: AUTOFREE: if this ls is no longer used do 681 device_remove_lockspace() */ 682 683 return 0; 684 } 685 686 static int copy_result_to_user(struct dlm_user_args *ua, int compat, 687 uint32_t flags, int mode, int copy_lvb, 688 char __user *buf, size_t count) 689 { 690 #ifdef CONFIG_COMPAT 691 struct dlm_lock_result32 result32; 692 #endif 693 struct dlm_lock_result result; 694 void *resultptr; 695 int error=0; 696 int len; 697 int struct_len; 698 699 memset(&result, 0, sizeof(struct dlm_lock_result)); 700 result.version[0] = DLM_DEVICE_VERSION_MAJOR; 701 result.version[1] = DLM_DEVICE_VERSION_MINOR; 702 result.version[2] = DLM_DEVICE_VERSION_PATCH; 703 memcpy(&result.lksb, &ua->lksb, offsetof(struct dlm_lksb, sb_lvbptr)); 704 result.user_lksb = ua->user_lksb; 705 706 /* FIXME: dlm1 provides for the user's bastparam/addr to not be updated 707 in a conversion unless the conversion is successful. See code 708 in dlm_user_convert() for updating ua from ua_tmp. OpenVMS, though, 709 notes that a new blocking AST address and parameter are set even if 710 the conversion fails, so maybe we should just do that. */ 711 712 if (flags & DLM_CB_BAST) { 713 result.user_astaddr = ua->bastaddr; 714 result.user_astparam = ua->bastparam; 715 result.bast_mode = mode; 716 } else { 717 result.user_astaddr = ua->castaddr; 718 result.user_astparam = ua->castparam; 719 } 720 721 #ifdef CONFIG_COMPAT 722 if (compat) 723 len = sizeof(struct dlm_lock_result32); 724 else 725 #endif 726 len = sizeof(struct dlm_lock_result); 727 struct_len = len; 728 729 /* copy lvb to userspace if there is one, it's been updated, and 730 the user buffer has space for it */ 731 732 if (copy_lvb && ua->lksb.sb_lvbptr && count >= len + DLM_USER_LVB_LEN) { 733 if (copy_to_user(buf+len, ua->lksb.sb_lvbptr, 734 DLM_USER_LVB_LEN)) { 735 error = -EFAULT; 736 goto out; 737 } 738 739 result.lvb_offset = len; 740 len += DLM_USER_LVB_LEN; 741 } 742 743 result.length = len; 744 resultptr = &result; 745 #ifdef CONFIG_COMPAT 746 if (compat) { 747 compat_output(&result, &result32); 748 resultptr = &result32; 749 } 750 #endif 751 752 if (copy_to_user(buf, resultptr, struct_len)) 753 error = -EFAULT; 754 else 755 error = len; 756 out: 757 return error; 758 } 759 760 static int copy_version_to_user(char __user *buf, size_t count) 761 { 762 struct dlm_device_version ver; 763 764 memset(&ver, 0, sizeof(struct dlm_device_version)); 765 ver.version[0] = DLM_DEVICE_VERSION_MAJOR; 766 ver.version[1] = DLM_DEVICE_VERSION_MINOR; 767 ver.version[2] = DLM_DEVICE_VERSION_PATCH; 768 769 if (copy_to_user(buf, &ver, sizeof(struct dlm_device_version))) 770 return -EFAULT; 771 return sizeof(struct dlm_device_version); 772 } 773 774 /* a read returns a single ast described in a struct dlm_lock_result */ 775 776 static ssize_t device_read(struct file *file, char __user *buf, size_t count, 777 loff_t *ppos) 778 { 779 struct dlm_user_proc *proc = file->private_data; 780 struct dlm_lkb *lkb; 781 DECLARE_WAITQUEUE(wait, current); 782 struct dlm_callback cb; 783 int rv, resid, copy_lvb = 0; 784 int old_mode, new_mode; 785 786 if (count == sizeof(struct dlm_device_version)) { 787 rv = copy_version_to_user(buf, count); 788 return rv; 789 } 790 791 if (!proc) { 792 log_print("non-version read from control device %zu", count); 793 return -EINVAL; 794 } 795 796 #ifdef CONFIG_COMPAT 797 if (count < sizeof(struct dlm_lock_result32)) 798 #else 799 if (count < sizeof(struct dlm_lock_result)) 800 #endif 801 return -EINVAL; 802 803 try_another: 804 805 /* do we really need this? can a read happen after a close? */ 806 if (test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags)) 807 return -EINVAL; 808 809 spin_lock(&proc->asts_spin); 810 if (list_empty(&proc->asts)) { 811 if (file->f_flags & O_NONBLOCK) { 812 spin_unlock(&proc->asts_spin); 813 return -EAGAIN; 814 } 815 816 add_wait_queue(&proc->wait, &wait); 817 818 repeat: 819 set_current_state(TASK_INTERRUPTIBLE); 820 if (list_empty(&proc->asts) && !signal_pending(current)) { 821 spin_unlock(&proc->asts_spin); 822 schedule(); 823 spin_lock(&proc->asts_spin); 824 goto repeat; 825 } 826 set_current_state(TASK_RUNNING); 827 remove_wait_queue(&proc->wait, &wait); 828 829 if (signal_pending(current)) { 830 spin_unlock(&proc->asts_spin); 831 return -ERESTARTSYS; 832 } 833 } 834 835 /* if we empty lkb_callbacks, we don't want to unlock the spinlock 836 without removing lkb_cb_list; so empty lkb_cb_list is always 837 consistent with empty lkb_callbacks */ 838 839 lkb = list_entry(proc->asts.next, struct dlm_lkb, lkb_cb_list); 840 841 /* rem_lkb_callback sets a new lkb_last_cast */ 842 old_mode = lkb->lkb_last_cast.mode; 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 new_mode = cb.mode; 868 869 if (!cb.sb_status && lkb->lkb_lksb->sb_lvbptr && 870 dlm_lvb_operations[old_mode + 1][new_mode + 1]) 871 copy_lvb = 1; 872 873 lkb->lkb_lksb->sb_status = cb.sb_status; 874 lkb->lkb_lksb->sb_flags = cb.sb_flags; 875 } 876 877 rv = copy_result_to_user(lkb->lkb_ua, 878 test_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags), 879 cb.flags, cb.mode, copy_lvb, buf, count); 880 881 /* removes ref for proc->asts, may cause lkb to be freed */ 882 if (!resid) 883 dlm_put_lkb(lkb); 884 885 return rv; 886 } 887 888 static __poll_t device_poll(struct file *file, poll_table *wait) 889 { 890 struct dlm_user_proc *proc = file->private_data; 891 892 poll_wait(file, &proc->wait, wait); 893 894 spin_lock(&proc->asts_spin); 895 if (!list_empty(&proc->asts)) { 896 spin_unlock(&proc->asts_spin); 897 return EPOLLIN | EPOLLRDNORM; 898 } 899 spin_unlock(&proc->asts_spin); 900 return 0; 901 } 902 903 int dlm_user_daemon_available(void) 904 { 905 /* dlm_controld hasn't started (or, has started, but not 906 properly populated configfs) */ 907 908 if (!dlm_our_nodeid()) 909 return 0; 910 911 /* This is to deal with versions of dlm_controld that don't 912 know about the monitor device. We assume that if the 913 dlm_controld was started (above), but the monitor device 914 was never opened, that it's an old version. dlm_controld 915 should open the monitor device before populating configfs. */ 916 917 if (dlm_monitor_unused) 918 return 1; 919 920 return atomic_read(&dlm_monitor_opened) ? 1 : 0; 921 } 922 923 static int ctl_device_open(struct inode *inode, struct file *file) 924 { 925 file->private_data = NULL; 926 return 0; 927 } 928 929 static int ctl_device_close(struct inode *inode, struct file *file) 930 { 931 return 0; 932 } 933 934 static int monitor_device_open(struct inode *inode, struct file *file) 935 { 936 atomic_inc(&dlm_monitor_opened); 937 dlm_monitor_unused = 0; 938 return 0; 939 } 940 941 static int monitor_device_close(struct inode *inode, struct file *file) 942 { 943 if (atomic_dec_and_test(&dlm_monitor_opened)) 944 dlm_stop_lockspaces(); 945 return 0; 946 } 947 948 static const struct file_operations device_fops = { 949 .open = device_open, 950 .release = device_close, 951 .read = device_read, 952 .write = device_write, 953 .poll = device_poll, 954 .owner = THIS_MODULE, 955 .llseek = noop_llseek, 956 }; 957 958 static const struct file_operations ctl_device_fops = { 959 .open = ctl_device_open, 960 .release = ctl_device_close, 961 .read = device_read, 962 .write = device_write, 963 .owner = THIS_MODULE, 964 .llseek = noop_llseek, 965 }; 966 967 static struct miscdevice ctl_device = { 968 .name = "dlm-control", 969 .fops = &ctl_device_fops, 970 .minor = MISC_DYNAMIC_MINOR, 971 }; 972 973 static const struct file_operations monitor_device_fops = { 974 .open = monitor_device_open, 975 .release = monitor_device_close, 976 .owner = THIS_MODULE, 977 .llseek = noop_llseek, 978 }; 979 980 static struct miscdevice monitor_device = { 981 .name = "dlm-monitor", 982 .fops = &monitor_device_fops, 983 .minor = MISC_DYNAMIC_MINOR, 984 }; 985 986 int __init dlm_user_init(void) 987 { 988 int error; 989 990 atomic_set(&dlm_monitor_opened, 0); 991 992 error = misc_register(&ctl_device); 993 if (error) { 994 log_print("misc_register failed for control device"); 995 goto out; 996 } 997 998 error = misc_register(&monitor_device); 999 if (error) { 1000 log_print("misc_register failed for monitor device"); 1001 misc_deregister(&ctl_device); 1002 } 1003 out: 1004 return error; 1005 } 1006 1007 void dlm_user_exit(void) 1008 { 1009 misc_deregister(&ctl_device); 1010 misc_deregister(&monitor_device); 1011 } 1012 1013