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 = (__user void *)(long)kb32->i.lock.castparam; 112 kb->i.lock.castaddr = (__user void *)(long)kb32->i.lock.castaddr; 113 kb->i.lock.bastparam = (__user void *)(long)kb32->i.lock.bastparam; 114 kb->i.lock.bastaddr = (__user void *)(long)kb32->i.lock.bastaddr; 115 kb->i.lock.lksb = (__user 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)(__force long)res->user_astaddr; 131 res32->user_astparam = (__u32)(__force long)res->user_astparam; 132 res32->user_lksb = (__u32)(__force 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 &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 /* this has to be set to NULL 358 * to avoid a double-free in dlm_device_deregister 359 */ 360 ls->ls_device.name = NULL; 361 } 362 fail: 363 return error; 364 } 365 366 int dlm_device_deregister(struct dlm_ls *ls) 367 { 368 /* The device is not registered. This happens when the lockspace 369 was never used from userspace, or when device_create_lockspace() 370 calls dlm_release_lockspace() after the register fails. */ 371 if (!ls->ls_device.name) 372 return 0; 373 374 misc_deregister(&ls->ls_device); 375 kfree(ls->ls_device.name); 376 return 0; 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, dlm_config.ci_cluster_name, 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 = memdup_user_nul(buf, count); 522 if (IS_ERR(kbuf)) 523 return PTR_ERR(kbuf); 524 525 if (check_version(kbuf)) { 526 error = -EBADE; 527 goto out_free; 528 } 529 530 #ifdef CONFIG_COMPAT 531 if (!kbuf->is64bit) { 532 struct dlm_write_request32 *k32buf; 533 int namelen = 0; 534 535 if (count > sizeof(struct dlm_write_request32)) 536 namelen = count - sizeof(struct dlm_write_request32); 537 538 k32buf = (struct dlm_write_request32 *)kbuf; 539 540 /* add 1 after namelen so that the name string is terminated */ 541 kbuf = kzalloc(sizeof(struct dlm_write_request) + namelen + 1, 542 GFP_NOFS); 543 if (!kbuf) { 544 kfree(k32buf); 545 return -ENOMEM; 546 } 547 548 if (proc) 549 set_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags); 550 551 compat_input(kbuf, k32buf, namelen); 552 kfree(k32buf); 553 } 554 #endif 555 556 /* do we really need this? can a write happen after a close? */ 557 if ((kbuf->cmd == DLM_USER_LOCK || kbuf->cmd == DLM_USER_UNLOCK) && 558 (proc && test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))) { 559 error = -EINVAL; 560 goto out_free; 561 } 562 563 error = -EINVAL; 564 565 switch (kbuf->cmd) 566 { 567 case DLM_USER_LOCK: 568 if (!proc) { 569 log_print("no locking on control device"); 570 goto out_free; 571 } 572 error = device_user_lock(proc, &kbuf->i.lock); 573 break; 574 575 case DLM_USER_UNLOCK: 576 if (!proc) { 577 log_print("no locking on control device"); 578 goto out_free; 579 } 580 error = device_user_unlock(proc, &kbuf->i.lock); 581 break; 582 583 case DLM_USER_DEADLOCK: 584 if (!proc) { 585 log_print("no locking on control device"); 586 goto out_free; 587 } 588 error = device_user_deadlock(proc, &kbuf->i.lock); 589 break; 590 591 case DLM_USER_CREATE_LOCKSPACE: 592 if (proc) { 593 log_print("create/remove only on control device"); 594 goto out_free; 595 } 596 error = device_create_lockspace(&kbuf->i.lspace); 597 break; 598 599 case DLM_USER_REMOVE_LOCKSPACE: 600 if (proc) { 601 log_print("create/remove only on control device"); 602 goto out_free; 603 } 604 error = device_remove_lockspace(&kbuf->i.lspace); 605 break; 606 607 case DLM_USER_PURGE: 608 if (!proc) { 609 log_print("no locking on control device"); 610 goto out_free; 611 } 612 error = device_user_purge(proc, &kbuf->i.purge); 613 break; 614 615 default: 616 log_print("Unknown command passed to DLM device : %d\n", 617 kbuf->cmd); 618 } 619 620 out_free: 621 kfree(kbuf); 622 return error; 623 } 624 625 /* Every process that opens the lockspace device has its own "proc" structure 626 hanging off the open file that's used to keep track of locks owned by the 627 process and asts that need to be delivered to the process. */ 628 629 static int device_open(struct inode *inode, struct file *file) 630 { 631 struct dlm_user_proc *proc; 632 struct dlm_ls *ls; 633 634 ls = dlm_find_lockspace_device(iminor(inode)); 635 if (!ls) 636 return -ENOENT; 637 638 proc = kzalloc(sizeof(struct dlm_user_proc), GFP_NOFS); 639 if (!proc) { 640 dlm_put_lockspace(ls); 641 return -ENOMEM; 642 } 643 644 proc->lockspace = ls->ls_local_handle; 645 INIT_LIST_HEAD(&proc->asts); 646 INIT_LIST_HEAD(&proc->locks); 647 INIT_LIST_HEAD(&proc->unlocking); 648 spin_lock_init(&proc->asts_spin); 649 spin_lock_init(&proc->locks_spin); 650 init_waitqueue_head(&proc->wait); 651 file->private_data = proc; 652 653 return 0; 654 } 655 656 static int device_close(struct inode *inode, struct file *file) 657 { 658 struct dlm_user_proc *proc = file->private_data; 659 struct dlm_ls *ls; 660 661 ls = dlm_find_lockspace_local(proc->lockspace); 662 if (!ls) 663 return -ENOENT; 664 665 set_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags); 666 667 dlm_clear_proc_locks(ls, proc); 668 669 /* at this point no more lkb's should exist for this lockspace, 670 so there's no chance of dlm_user_add_ast() being called and 671 looking for lkb->ua->proc */ 672 673 kfree(proc); 674 file->private_data = NULL; 675 676 dlm_put_lockspace(ls); 677 dlm_put_lockspace(ls); /* for the find in device_open() */ 678 679 /* FIXME: AUTOFREE: if this ls is no longer used do 680 device_remove_lockspace() */ 681 682 return 0; 683 } 684 685 static int copy_result_to_user(struct dlm_user_args *ua, int compat, 686 uint32_t flags, int mode, int copy_lvb, 687 char __user *buf, size_t count) 688 { 689 #ifdef CONFIG_COMPAT 690 struct dlm_lock_result32 result32; 691 #endif 692 struct dlm_lock_result result; 693 void *resultptr; 694 int error=0; 695 int len; 696 int struct_len; 697 698 memset(&result, 0, sizeof(struct dlm_lock_result)); 699 result.version[0] = DLM_DEVICE_VERSION_MAJOR; 700 result.version[1] = DLM_DEVICE_VERSION_MINOR; 701 result.version[2] = DLM_DEVICE_VERSION_PATCH; 702 memcpy(&result.lksb, &ua->lksb, offsetof(struct dlm_lksb, sb_lvbptr)); 703 result.user_lksb = ua->user_lksb; 704 705 /* FIXME: dlm1 provides for the user's bastparam/addr to not be updated 706 in a conversion unless the conversion is successful. See code 707 in dlm_user_convert() for updating ua from ua_tmp. OpenVMS, though, 708 notes that a new blocking AST address and parameter are set even if 709 the conversion fails, so maybe we should just do that. */ 710 711 if (flags & DLM_CB_BAST) { 712 result.user_astaddr = ua->bastaddr; 713 result.user_astparam = ua->bastparam; 714 result.bast_mode = mode; 715 } else { 716 result.user_astaddr = ua->castaddr; 717 result.user_astparam = ua->castparam; 718 } 719 720 #ifdef CONFIG_COMPAT 721 if (compat) 722 len = sizeof(struct dlm_lock_result32); 723 else 724 #endif 725 len = sizeof(struct dlm_lock_result); 726 struct_len = len; 727 728 /* copy lvb to userspace if there is one, it's been updated, and 729 the user buffer has space for it */ 730 731 if (copy_lvb && ua->lksb.sb_lvbptr && count >= len + DLM_USER_LVB_LEN) { 732 if (copy_to_user(buf+len, ua->lksb.sb_lvbptr, 733 DLM_USER_LVB_LEN)) { 734 error = -EFAULT; 735 goto out; 736 } 737 738 result.lvb_offset = len; 739 len += DLM_USER_LVB_LEN; 740 } 741 742 result.length = len; 743 resultptr = &result; 744 #ifdef CONFIG_COMPAT 745 if (compat) { 746 compat_output(&result, &result32); 747 resultptr = &result32; 748 } 749 #endif 750 751 if (copy_to_user(buf, resultptr, struct_len)) 752 error = -EFAULT; 753 else 754 error = len; 755 out: 756 return error; 757 } 758 759 static int copy_version_to_user(char __user *buf, size_t count) 760 { 761 struct dlm_device_version ver; 762 763 memset(&ver, 0, sizeof(struct dlm_device_version)); 764 ver.version[0] = DLM_DEVICE_VERSION_MAJOR; 765 ver.version[1] = DLM_DEVICE_VERSION_MINOR; 766 ver.version[2] = DLM_DEVICE_VERSION_PATCH; 767 768 if (copy_to_user(buf, &ver, sizeof(struct dlm_device_version))) 769 return -EFAULT; 770 return sizeof(struct dlm_device_version); 771 } 772 773 /* a read returns a single ast described in a struct dlm_lock_result */ 774 775 static ssize_t device_read(struct file *file, char __user *buf, size_t count, 776 loff_t *ppos) 777 { 778 struct dlm_user_proc *proc = file->private_data; 779 struct dlm_lkb *lkb; 780 DECLARE_WAITQUEUE(wait, current); 781 struct dlm_callback cb; 782 int rv, resid, copy_lvb = 0; 783 int old_mode, new_mode; 784 785 if (count == sizeof(struct dlm_device_version)) { 786 rv = copy_version_to_user(buf, count); 787 return rv; 788 } 789 790 if (!proc) { 791 log_print("non-version read from control device %zu", count); 792 return -EINVAL; 793 } 794 795 #ifdef CONFIG_COMPAT 796 if (count < sizeof(struct dlm_lock_result32)) 797 #else 798 if (count < sizeof(struct dlm_lock_result)) 799 #endif 800 return -EINVAL; 801 802 try_another: 803 804 /* do we really need this? can a read happen after a close? */ 805 if (test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags)) 806 return -EINVAL; 807 808 spin_lock(&proc->asts_spin); 809 if (list_empty(&proc->asts)) { 810 if (file->f_flags & O_NONBLOCK) { 811 spin_unlock(&proc->asts_spin); 812 return -EAGAIN; 813 } 814 815 add_wait_queue(&proc->wait, &wait); 816 817 repeat: 818 set_current_state(TASK_INTERRUPTIBLE); 819 if (list_empty(&proc->asts) && !signal_pending(current)) { 820 spin_unlock(&proc->asts_spin); 821 schedule(); 822 spin_lock(&proc->asts_spin); 823 goto repeat; 824 } 825 set_current_state(TASK_RUNNING); 826 remove_wait_queue(&proc->wait, &wait); 827 828 if (signal_pending(current)) { 829 spin_unlock(&proc->asts_spin); 830 return -ERESTARTSYS; 831 } 832 } 833 834 /* if we empty lkb_callbacks, we don't want to unlock the spinlock 835 without removing lkb_cb_list; so empty lkb_cb_list is always 836 consistent with empty lkb_callbacks */ 837 838 lkb = list_entry(proc->asts.next, struct dlm_lkb, lkb_cb_list); 839 840 /* rem_lkb_callback sets a new lkb_last_cast */ 841 old_mode = lkb->lkb_last_cast.mode; 842 843 rv = dlm_rem_lkb_callback(lkb->lkb_resource->res_ls, lkb, &cb, &resid); 844 if (rv < 0) { 845 /* this shouldn't happen; lkb should have been removed from 846 list when resid was zero */ 847 log_print("dlm_rem_lkb_callback empty %x", lkb->lkb_id); 848 list_del_init(&lkb->lkb_cb_list); 849 spin_unlock(&proc->asts_spin); 850 /* removes ref for proc->asts, may cause lkb to be freed */ 851 dlm_put_lkb(lkb); 852 goto try_another; 853 } 854 if (!resid) 855 list_del_init(&lkb->lkb_cb_list); 856 spin_unlock(&proc->asts_spin); 857 858 if (cb.flags & DLM_CB_SKIP) { 859 /* removes ref for proc->asts, may cause lkb to be freed */ 860 if (!resid) 861 dlm_put_lkb(lkb); 862 goto try_another; 863 } 864 865 if (cb.flags & DLM_CB_CAST) { 866 new_mode = cb.mode; 867 868 if (!cb.sb_status && lkb->lkb_lksb->sb_lvbptr && 869 dlm_lvb_operations[old_mode + 1][new_mode + 1]) 870 copy_lvb = 1; 871 872 lkb->lkb_lksb->sb_status = cb.sb_status; 873 lkb->lkb_lksb->sb_flags = cb.sb_flags; 874 } 875 876 rv = copy_result_to_user(lkb->lkb_ua, 877 test_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags), 878 cb.flags, cb.mode, copy_lvb, buf, count); 879 880 /* removes ref for proc->asts, may cause lkb to be freed */ 881 if (!resid) 882 dlm_put_lkb(lkb); 883 884 return rv; 885 } 886 887 static __poll_t device_poll(struct file *file, poll_table *wait) 888 { 889 struct dlm_user_proc *proc = file->private_data; 890 891 poll_wait(file, &proc->wait, wait); 892 893 spin_lock(&proc->asts_spin); 894 if (!list_empty(&proc->asts)) { 895 spin_unlock(&proc->asts_spin); 896 return EPOLLIN | EPOLLRDNORM; 897 } 898 spin_unlock(&proc->asts_spin); 899 return 0; 900 } 901 902 int dlm_user_daemon_available(void) 903 { 904 /* dlm_controld hasn't started (or, has started, but not 905 properly populated configfs) */ 906 907 if (!dlm_our_nodeid()) 908 return 0; 909 910 /* This is to deal with versions of dlm_controld that don't 911 know about the monitor device. We assume that if the 912 dlm_controld was started (above), but the monitor device 913 was never opened, that it's an old version. dlm_controld 914 should open the monitor device before populating configfs. */ 915 916 if (dlm_monitor_unused) 917 return 1; 918 919 return atomic_read(&dlm_monitor_opened) ? 1 : 0; 920 } 921 922 static int ctl_device_open(struct inode *inode, struct file *file) 923 { 924 file->private_data = NULL; 925 return 0; 926 } 927 928 static int ctl_device_close(struct inode *inode, struct file *file) 929 { 930 return 0; 931 } 932 933 static int monitor_device_open(struct inode *inode, struct file *file) 934 { 935 atomic_inc(&dlm_monitor_opened); 936 dlm_monitor_unused = 0; 937 return 0; 938 } 939 940 static int monitor_device_close(struct inode *inode, struct file *file) 941 { 942 if (atomic_dec_and_test(&dlm_monitor_opened)) 943 dlm_stop_lockspaces(); 944 return 0; 945 } 946 947 static const struct file_operations device_fops = { 948 .open = device_open, 949 .release = device_close, 950 .read = device_read, 951 .write = device_write, 952 .poll = device_poll, 953 .owner = THIS_MODULE, 954 .llseek = noop_llseek, 955 }; 956 957 static const struct file_operations ctl_device_fops = { 958 .open = ctl_device_open, 959 .release = ctl_device_close, 960 .read = device_read, 961 .write = device_write, 962 .owner = THIS_MODULE, 963 .llseek = noop_llseek, 964 }; 965 966 static struct miscdevice ctl_device = { 967 .name = "dlm-control", 968 .fops = &ctl_device_fops, 969 .minor = MISC_DYNAMIC_MINOR, 970 }; 971 972 static const struct file_operations monitor_device_fops = { 973 .open = monitor_device_open, 974 .release = monitor_device_close, 975 .owner = THIS_MODULE, 976 .llseek = noop_llseek, 977 }; 978 979 static struct miscdevice monitor_device = { 980 .name = "dlm-monitor", 981 .fops = &monitor_device_fops, 982 .minor = MISC_DYNAMIC_MINOR, 983 }; 984 985 int __init dlm_user_init(void) 986 { 987 int error; 988 989 atomic_set(&dlm_monitor_opened, 0); 990 991 error = misc_register(&ctl_device); 992 if (error) { 993 log_print("misc_register failed for control device"); 994 goto out; 995 } 996 997 error = misc_register(&monitor_device); 998 if (error) { 999 log_print("misc_register failed for monitor device"); 1000 misc_deregister(&ctl_device); 1001 } 1002 out: 1003 return error; 1004 } 1005 1006 void dlm_user_exit(void) 1007 { 1008 misc_deregister(&ctl_device); 1009 misc_deregister(&monitor_device); 1010 } 1011 1012