1 /* 2 * Copyright (C) 2006-2010 Red Hat, Inc. All rights reserved. 3 * 4 * This copyrighted material is made available to anyone wishing to use, 5 * modify, copy, or redistribute it subject to the terms and conditions 6 * of the GNU General Public License v.2. 7 */ 8 9 #include <linux/miscdevice.h> 10 #include <linux/init.h> 11 #include <linux/wait.h> 12 #include <linux/file.h> 13 #include <linux/fs.h> 14 #include <linux/poll.h> 15 #include <linux/signal.h> 16 #include <linux/spinlock.h> 17 #include <linux/dlm.h> 18 #include <linux/dlm_device.h> 19 #include <linux/slab.h> 20 #include <linux/sched/signal.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 memset(res32, 0, sizeof(*res32)); 127 128 res32->version[0] = res->version[0]; 129 res32->version[1] = res->version[1]; 130 res32->version[2] = res->version[2]; 131 132 res32->user_astaddr = (__u32)(long)res->user_astaddr; 133 res32->user_astparam = (__u32)(long)res->user_astparam; 134 res32->user_lksb = (__u32)(long)res->user_lksb; 135 res32->bast_mode = res->bast_mode; 136 137 res32->lvb_offset = res->lvb_offset; 138 res32->length = res->length; 139 140 res32->lksb.sb_status = res->lksb.sb_status; 141 res32->lksb.sb_flags = res->lksb.sb_flags; 142 res32->lksb.sb_lkid = res->lksb.sb_lkid; 143 res32->lksb.sb_lvbptr = (__u32)(long)res->lksb.sb_lvbptr; 144 } 145 #endif 146 147 /* Figure out if this lock is at the end of its life and no longer 148 available for the application to use. The lkb still exists until 149 the final ast is read. A lock becomes EOL in three situations: 150 1. a noqueue request fails with EAGAIN 151 2. an unlock completes with EUNLOCK 152 3. a cancel of a waiting request completes with ECANCEL/EDEADLK 153 An EOL lock needs to be removed from the process's list of locks. 154 And we can't allow any new operation on an EOL lock. This is 155 not related to the lifetime of the lkb struct which is managed 156 entirely by refcount. */ 157 158 static int lkb_is_endoflife(int mode, int status) 159 { 160 switch (status) { 161 case -DLM_EUNLOCK: 162 return 1; 163 case -DLM_ECANCEL: 164 case -ETIMEDOUT: 165 case -EDEADLK: 166 case -EAGAIN: 167 if (mode == DLM_LOCK_IV) 168 return 1; 169 break; 170 } 171 return 0; 172 } 173 174 /* we could possibly check if the cancel of an orphan has resulted in the lkb 175 being removed and then remove that lkb from the orphans list and free it */ 176 177 void dlm_user_add_ast(struct dlm_lkb *lkb, uint32_t flags, int mode, 178 int status, uint32_t sbflags, uint64_t seq) 179 { 180 struct dlm_ls *ls; 181 struct dlm_user_args *ua; 182 struct dlm_user_proc *proc; 183 int rv; 184 185 if (lkb->lkb_flags & (DLM_IFL_ORPHAN | DLM_IFL_DEAD)) 186 return; 187 188 ls = lkb->lkb_resource->res_ls; 189 mutex_lock(&ls->ls_clear_proc_locks); 190 191 /* If ORPHAN/DEAD flag is set, it means the process is dead so an ast 192 can't be delivered. For ORPHAN's, dlm_clear_proc_locks() freed 193 lkb->ua so we can't try to use it. This second check is necessary 194 for cases where a completion ast is received for an operation that 195 began before clear_proc_locks did its cancel/unlock. */ 196 197 if (lkb->lkb_flags & (DLM_IFL_ORPHAN | DLM_IFL_DEAD)) 198 goto out; 199 200 DLM_ASSERT(lkb->lkb_ua, dlm_print_lkb(lkb);); 201 ua = lkb->lkb_ua; 202 proc = ua->proc; 203 204 if ((flags & DLM_CB_BAST) && ua->bastaddr == NULL) 205 goto out; 206 207 if ((flags & DLM_CB_CAST) && lkb_is_endoflife(mode, status)) 208 lkb->lkb_flags |= DLM_IFL_ENDOFLIFE; 209 210 spin_lock(&proc->asts_spin); 211 212 rv = dlm_add_lkb_callback(lkb, flags, mode, status, sbflags, seq); 213 if (rv < 0) { 214 spin_unlock(&proc->asts_spin); 215 goto out; 216 } 217 218 if (list_empty(&lkb->lkb_cb_list)) { 219 kref_get(&lkb->lkb_ref); 220 list_add_tail(&lkb->lkb_cb_list, &proc->asts); 221 wake_up_interruptible(&proc->wait); 222 } 223 spin_unlock(&proc->asts_spin); 224 225 if (lkb->lkb_flags & DLM_IFL_ENDOFLIFE) { 226 /* N.B. spin_lock locks_spin, not asts_spin */ 227 spin_lock(&proc->locks_spin); 228 if (!list_empty(&lkb->lkb_ownqueue)) { 229 list_del_init(&lkb->lkb_ownqueue); 230 dlm_put_lkb(lkb); 231 } 232 spin_unlock(&proc->locks_spin); 233 } 234 out: 235 mutex_unlock(&ls->ls_clear_proc_locks); 236 } 237 238 static int device_user_lock(struct dlm_user_proc *proc, 239 struct dlm_lock_params *params) 240 { 241 struct dlm_ls *ls; 242 struct dlm_user_args *ua; 243 uint32_t lkid; 244 int error = -ENOMEM; 245 246 ls = dlm_find_lockspace_local(proc->lockspace); 247 if (!ls) 248 return -ENOENT; 249 250 if (!params->castaddr || !params->lksb) { 251 error = -EINVAL; 252 goto out; 253 } 254 255 ua = kzalloc(sizeof(struct dlm_user_args), GFP_NOFS); 256 if (!ua) 257 goto out; 258 ua->proc = proc; 259 ua->user_lksb = params->lksb; 260 ua->castparam = params->castparam; 261 ua->castaddr = params->castaddr; 262 ua->bastparam = params->bastparam; 263 ua->bastaddr = params->bastaddr; 264 ua->xid = params->xid; 265 266 if (params->flags & DLM_LKF_CONVERT) { 267 error = dlm_user_convert(ls, ua, 268 params->mode, params->flags, 269 params->lkid, params->lvb, 270 (unsigned long) params->timeout); 271 } else if (params->flags & DLM_LKF_ORPHAN) { 272 error = dlm_user_adopt_orphan(ls, ua, 273 params->mode, params->flags, 274 params->name, params->namelen, 275 (unsigned long) params->timeout, 276 &lkid); 277 if (!error) 278 error = lkid; 279 } else { 280 error = dlm_user_request(ls, ua, 281 params->mode, params->flags, 282 params->name, params->namelen, 283 (unsigned long) params->timeout); 284 if (!error) 285 error = ua->lksb.sb_lkid; 286 } 287 out: 288 dlm_put_lockspace(ls); 289 return error; 290 } 291 292 static int device_user_unlock(struct dlm_user_proc *proc, 293 struct dlm_lock_params *params) 294 { 295 struct dlm_ls *ls; 296 struct dlm_user_args *ua; 297 int error = -ENOMEM; 298 299 ls = dlm_find_lockspace_local(proc->lockspace); 300 if (!ls) 301 return -ENOENT; 302 303 ua = kzalloc(sizeof(struct dlm_user_args), GFP_NOFS); 304 if (!ua) 305 goto out; 306 ua->proc = proc; 307 ua->user_lksb = params->lksb; 308 ua->castparam = params->castparam; 309 ua->castaddr = params->castaddr; 310 311 if (params->flags & DLM_LKF_CANCEL) 312 error = dlm_user_cancel(ls, ua, params->flags, params->lkid); 313 else 314 error = dlm_user_unlock(ls, ua, params->flags, params->lkid, 315 params->lvb); 316 out: 317 dlm_put_lockspace(ls); 318 return error; 319 } 320 321 static int device_user_deadlock(struct dlm_user_proc *proc, 322 struct dlm_lock_params *params) 323 { 324 struct dlm_ls *ls; 325 int error; 326 327 ls = dlm_find_lockspace_local(proc->lockspace); 328 if (!ls) 329 return -ENOENT; 330 331 error = dlm_user_deadlock(ls, params->flags, params->lkid); 332 333 dlm_put_lockspace(ls); 334 return error; 335 } 336 337 static int dlm_device_register(struct dlm_ls *ls, char *name) 338 { 339 int error, len; 340 341 /* The device is already registered. This happens when the 342 lockspace is created multiple times from userspace. */ 343 if (ls->ls_device.name) 344 return 0; 345 346 error = -ENOMEM; 347 len = strlen(name) + strlen(name_prefix) + 2; 348 ls->ls_device.name = kzalloc(len, GFP_NOFS); 349 if (!ls->ls_device.name) 350 goto fail; 351 352 snprintf((char *)ls->ls_device.name, len, "%s_%s", name_prefix, 353 name); 354 ls->ls_device.fops = &device_fops; 355 ls->ls_device.minor = MISC_DYNAMIC_MINOR; 356 357 error = misc_register(&ls->ls_device); 358 if (error) { 359 kfree(ls->ls_device.name); 360 /* this has to be set to NULL 361 * to avoid a double-free in dlm_device_deregister 362 */ 363 ls->ls_device.name = NULL; 364 } 365 fail: 366 return error; 367 } 368 369 int dlm_device_deregister(struct dlm_ls *ls) 370 { 371 /* The device is not registered. This happens when the lockspace 372 was never used from userspace, or when device_create_lockspace() 373 calls dlm_release_lockspace() after the register fails. */ 374 if (!ls->ls_device.name) 375 return 0; 376 377 misc_deregister(&ls->ls_device); 378 kfree(ls->ls_device.name); 379 return 0; 380 } 381 382 static int device_user_purge(struct dlm_user_proc *proc, 383 struct dlm_purge_params *params) 384 { 385 struct dlm_ls *ls; 386 int error; 387 388 ls = dlm_find_lockspace_local(proc->lockspace); 389 if (!ls) 390 return -ENOENT; 391 392 error = dlm_user_purge(ls, proc, params->nodeid, params->pid); 393 394 dlm_put_lockspace(ls); 395 return error; 396 } 397 398 static int device_create_lockspace(struct dlm_lspace_params *params) 399 { 400 dlm_lockspace_t *lockspace; 401 struct dlm_ls *ls; 402 int error; 403 404 if (!capable(CAP_SYS_ADMIN)) 405 return -EPERM; 406 407 error = dlm_new_lockspace(params->name, NULL, params->flags, 408 DLM_USER_LVB_LEN, NULL, NULL, NULL, 409 &lockspace); 410 if (error) 411 return error; 412 413 ls = dlm_find_lockspace_local(lockspace); 414 if (!ls) 415 return -ENOENT; 416 417 error = dlm_device_register(ls, params->name); 418 dlm_put_lockspace(ls); 419 420 if (error) 421 dlm_release_lockspace(lockspace, 0); 422 else 423 error = ls->ls_device.minor; 424 425 return error; 426 } 427 428 static int device_remove_lockspace(struct dlm_lspace_params *params) 429 { 430 dlm_lockspace_t *lockspace; 431 struct dlm_ls *ls; 432 int error, force = 0; 433 434 if (!capable(CAP_SYS_ADMIN)) 435 return -EPERM; 436 437 ls = dlm_find_lockspace_device(params->minor); 438 if (!ls) 439 return -ENOENT; 440 441 if (params->flags & DLM_USER_LSFLG_FORCEFREE) 442 force = 2; 443 444 lockspace = ls->ls_local_handle; 445 dlm_put_lockspace(ls); 446 447 /* The final dlm_release_lockspace waits for references to go to 448 zero, so all processes will need to close their device for the 449 ls before the release will proceed. release also calls the 450 device_deregister above. Converting a positive return value 451 from release to zero means that userspace won't know when its 452 release was the final one, but it shouldn't need to know. */ 453 454 error = dlm_release_lockspace(lockspace, force); 455 if (error > 0) 456 error = 0; 457 return error; 458 } 459 460 /* Check the user's version matches ours */ 461 static int check_version(struct dlm_write_request *req) 462 { 463 if (req->version[0] != DLM_DEVICE_VERSION_MAJOR || 464 (req->version[0] == DLM_DEVICE_VERSION_MAJOR && 465 req->version[1] > DLM_DEVICE_VERSION_MINOR)) { 466 467 printk(KERN_DEBUG "dlm: process %s (%d) version mismatch " 468 "user (%d.%d.%d) kernel (%d.%d.%d)\n", 469 current->comm, 470 task_pid_nr(current), 471 req->version[0], 472 req->version[1], 473 req->version[2], 474 DLM_DEVICE_VERSION_MAJOR, 475 DLM_DEVICE_VERSION_MINOR, 476 DLM_DEVICE_VERSION_PATCH); 477 return -EINVAL; 478 } 479 return 0; 480 } 481 482 /* 483 * device_write 484 * 485 * device_user_lock 486 * dlm_user_request -> request_lock 487 * dlm_user_convert -> convert_lock 488 * 489 * device_user_unlock 490 * dlm_user_unlock -> unlock_lock 491 * dlm_user_cancel -> cancel_lock 492 * 493 * device_create_lockspace 494 * dlm_new_lockspace 495 * 496 * device_remove_lockspace 497 * dlm_release_lockspace 498 */ 499 500 /* a write to a lockspace device is a lock or unlock request, a write 501 to the control device is to create/remove a lockspace */ 502 503 static ssize_t device_write(struct file *file, const char __user *buf, 504 size_t count, loff_t *ppos) 505 { 506 struct dlm_user_proc *proc = file->private_data; 507 struct dlm_write_request *kbuf; 508 int error; 509 510 #ifdef CONFIG_COMPAT 511 if (count < sizeof(struct dlm_write_request32)) 512 #else 513 if (count < sizeof(struct dlm_write_request)) 514 #endif 515 return -EINVAL; 516 517 /* 518 * can't compare against COMPAT/dlm_write_request32 because 519 * we don't yet know if is64bit is zero 520 */ 521 if (count > sizeof(struct dlm_write_request) + DLM_RESNAME_MAXLEN) 522 return -EINVAL; 523 524 kbuf = memdup_user_nul(buf, count); 525 if (IS_ERR(kbuf)) 526 return PTR_ERR(kbuf); 527 528 if (check_version(kbuf)) { 529 error = -EBADE; 530 goto out_free; 531 } 532 533 #ifdef CONFIG_COMPAT 534 if (!kbuf->is64bit) { 535 struct dlm_write_request32 *k32buf; 536 int namelen = 0; 537 538 if (count > sizeof(struct dlm_write_request32)) 539 namelen = count - sizeof(struct dlm_write_request32); 540 541 k32buf = (struct dlm_write_request32 *)kbuf; 542 543 /* add 1 after namelen so that the name string is terminated */ 544 kbuf = kzalloc(sizeof(struct dlm_write_request) + namelen + 1, 545 GFP_NOFS); 546 if (!kbuf) { 547 kfree(k32buf); 548 return -ENOMEM; 549 } 550 551 if (proc) 552 set_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags); 553 554 compat_input(kbuf, k32buf, namelen); 555 kfree(k32buf); 556 } 557 #endif 558 559 /* do we really need this? can a write happen after a close? */ 560 if ((kbuf->cmd == DLM_USER_LOCK || kbuf->cmd == DLM_USER_UNLOCK) && 561 (proc && test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))) { 562 error = -EINVAL; 563 goto out_free; 564 } 565 566 error = -EINVAL; 567 568 switch (kbuf->cmd) 569 { 570 case DLM_USER_LOCK: 571 if (!proc) { 572 log_print("no locking on control device"); 573 goto out_free; 574 } 575 error = device_user_lock(proc, &kbuf->i.lock); 576 break; 577 578 case DLM_USER_UNLOCK: 579 if (!proc) { 580 log_print("no locking on control device"); 581 goto out_free; 582 } 583 error = device_user_unlock(proc, &kbuf->i.lock); 584 break; 585 586 case DLM_USER_DEADLOCK: 587 if (!proc) { 588 log_print("no locking on control device"); 589 goto out_free; 590 } 591 error = device_user_deadlock(proc, &kbuf->i.lock); 592 break; 593 594 case DLM_USER_CREATE_LOCKSPACE: 595 if (proc) { 596 log_print("create/remove only on control device"); 597 goto out_free; 598 } 599 error = device_create_lockspace(&kbuf->i.lspace); 600 break; 601 602 case DLM_USER_REMOVE_LOCKSPACE: 603 if (proc) { 604 log_print("create/remove only on control device"); 605 goto out_free; 606 } 607 error = device_remove_lockspace(&kbuf->i.lspace); 608 break; 609 610 case DLM_USER_PURGE: 611 if (!proc) { 612 log_print("no locking on control device"); 613 goto out_free; 614 } 615 error = device_user_purge(proc, &kbuf->i.purge); 616 break; 617 618 default: 619 log_print("Unknown command passed to DLM device : %d\n", 620 kbuf->cmd); 621 } 622 623 out_free: 624 kfree(kbuf); 625 return error; 626 } 627 628 /* Every process that opens the lockspace device has its own "proc" structure 629 hanging off the open file that's used to keep track of locks owned by the 630 process and asts that need to be delivered to the process. */ 631 632 static int device_open(struct inode *inode, struct file *file) 633 { 634 struct dlm_user_proc *proc; 635 struct dlm_ls *ls; 636 637 ls = dlm_find_lockspace_device(iminor(inode)); 638 if (!ls) 639 return -ENOENT; 640 641 proc = kzalloc(sizeof(struct dlm_user_proc), GFP_NOFS); 642 if (!proc) { 643 dlm_put_lockspace(ls); 644 return -ENOMEM; 645 } 646 647 proc->lockspace = ls->ls_local_handle; 648 INIT_LIST_HEAD(&proc->asts); 649 INIT_LIST_HEAD(&proc->locks); 650 INIT_LIST_HEAD(&proc->unlocking); 651 spin_lock_init(&proc->asts_spin); 652 spin_lock_init(&proc->locks_spin); 653 init_waitqueue_head(&proc->wait); 654 file->private_data = proc; 655 656 return 0; 657 } 658 659 static int device_close(struct inode *inode, struct file *file) 660 { 661 struct dlm_user_proc *proc = file->private_data; 662 struct dlm_ls *ls; 663 664 ls = dlm_find_lockspace_local(proc->lockspace); 665 if (!ls) 666 return -ENOENT; 667 668 set_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags); 669 670 dlm_clear_proc_locks(ls, proc); 671 672 /* at this point no more lkb's should exist for this lockspace, 673 so there's no chance of dlm_user_add_ast() being called and 674 looking for lkb->ua->proc */ 675 676 kfree(proc); 677 file->private_data = NULL; 678 679 dlm_put_lockspace(ls); 680 dlm_put_lockspace(ls); /* for the find in device_open() */ 681 682 /* FIXME: AUTOFREE: if this ls is no longer used do 683 device_remove_lockspace() */ 684 685 return 0; 686 } 687 688 static int copy_result_to_user(struct dlm_user_args *ua, int compat, 689 uint32_t flags, int mode, int copy_lvb, 690 char __user *buf, size_t count) 691 { 692 #ifdef CONFIG_COMPAT 693 struct dlm_lock_result32 result32; 694 #endif 695 struct dlm_lock_result result; 696 void *resultptr; 697 int error=0; 698 int len; 699 int struct_len; 700 701 memset(&result, 0, sizeof(struct dlm_lock_result)); 702 result.version[0] = DLM_DEVICE_VERSION_MAJOR; 703 result.version[1] = DLM_DEVICE_VERSION_MINOR; 704 result.version[2] = DLM_DEVICE_VERSION_PATCH; 705 memcpy(&result.lksb, &ua->lksb, sizeof(struct dlm_lksb)); 706 result.user_lksb = ua->user_lksb; 707 708 /* FIXME: dlm1 provides for the user's bastparam/addr to not be updated 709 in a conversion unless the conversion is successful. See code 710 in dlm_user_convert() for updating ua from ua_tmp. OpenVMS, though, 711 notes that a new blocking AST address and parameter are set even if 712 the conversion fails, so maybe we should just do that. */ 713 714 if (flags & DLM_CB_BAST) { 715 result.user_astaddr = ua->bastaddr; 716 result.user_astparam = ua->bastparam; 717 result.bast_mode = mode; 718 } else { 719 result.user_astaddr = ua->castaddr; 720 result.user_astparam = ua->castparam; 721 } 722 723 #ifdef CONFIG_COMPAT 724 if (compat) 725 len = sizeof(struct dlm_lock_result32); 726 else 727 #endif 728 len = sizeof(struct dlm_lock_result); 729 struct_len = len; 730 731 /* copy lvb to userspace if there is one, it's been updated, and 732 the user buffer has space for it */ 733 734 if (copy_lvb && ua->lksb.sb_lvbptr && count >= len + DLM_USER_LVB_LEN) { 735 if (copy_to_user(buf+len, ua->lksb.sb_lvbptr, 736 DLM_USER_LVB_LEN)) { 737 error = -EFAULT; 738 goto out; 739 } 740 741 result.lvb_offset = len; 742 len += DLM_USER_LVB_LEN; 743 } 744 745 result.length = len; 746 resultptr = &result; 747 #ifdef CONFIG_COMPAT 748 if (compat) { 749 compat_output(&result, &result32); 750 resultptr = &result32; 751 } 752 #endif 753 754 if (copy_to_user(buf, resultptr, struct_len)) 755 error = -EFAULT; 756 else 757 error = len; 758 out: 759 return error; 760 } 761 762 static int copy_version_to_user(char __user *buf, size_t count) 763 { 764 struct dlm_device_version ver; 765 766 memset(&ver, 0, sizeof(struct dlm_device_version)); 767 ver.version[0] = DLM_DEVICE_VERSION_MAJOR; 768 ver.version[1] = DLM_DEVICE_VERSION_MINOR; 769 ver.version[2] = DLM_DEVICE_VERSION_PATCH; 770 771 if (copy_to_user(buf, &ver, sizeof(struct dlm_device_version))) 772 return -EFAULT; 773 return sizeof(struct dlm_device_version); 774 } 775 776 /* a read returns a single ast described in a struct dlm_lock_result */ 777 778 static ssize_t device_read(struct file *file, char __user *buf, size_t count, 779 loff_t *ppos) 780 { 781 struct dlm_user_proc *proc = file->private_data; 782 struct dlm_lkb *lkb; 783 DECLARE_WAITQUEUE(wait, current); 784 struct dlm_callback cb; 785 int rv, resid, copy_lvb = 0; 786 int old_mode, new_mode; 787 788 if (count == sizeof(struct dlm_device_version)) { 789 rv = copy_version_to_user(buf, count); 790 return rv; 791 } 792 793 if (!proc) { 794 log_print("non-version read from control device %zu", count); 795 return -EINVAL; 796 } 797 798 #ifdef CONFIG_COMPAT 799 if (count < sizeof(struct dlm_lock_result32)) 800 #else 801 if (count < sizeof(struct dlm_lock_result)) 802 #endif 803 return -EINVAL; 804 805 try_another: 806 807 /* do we really need this? can a read happen after a close? */ 808 if (test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags)) 809 return -EINVAL; 810 811 spin_lock(&proc->asts_spin); 812 if (list_empty(&proc->asts)) { 813 if (file->f_flags & O_NONBLOCK) { 814 spin_unlock(&proc->asts_spin); 815 return -EAGAIN; 816 } 817 818 add_wait_queue(&proc->wait, &wait); 819 820 repeat: 821 set_current_state(TASK_INTERRUPTIBLE); 822 if (list_empty(&proc->asts) && !signal_pending(current)) { 823 spin_unlock(&proc->asts_spin); 824 schedule(); 825 spin_lock(&proc->asts_spin); 826 goto repeat; 827 } 828 set_current_state(TASK_RUNNING); 829 remove_wait_queue(&proc->wait, &wait); 830 831 if (signal_pending(current)) { 832 spin_unlock(&proc->asts_spin); 833 return -ERESTARTSYS; 834 } 835 } 836 837 /* if we empty lkb_callbacks, we don't want to unlock the spinlock 838 without removing lkb_cb_list; so empty lkb_cb_list is always 839 consistent with empty lkb_callbacks */ 840 841 lkb = list_entry(proc->asts.next, struct dlm_lkb, lkb_cb_list); 842 843 /* rem_lkb_callback sets a new lkb_last_cast */ 844 old_mode = lkb->lkb_last_cast.mode; 845 846 rv = dlm_rem_lkb_callback(lkb->lkb_resource->res_ls, lkb, &cb, &resid); 847 if (rv < 0) { 848 /* this shouldn't happen; lkb should have been removed from 849 list when resid was zero */ 850 log_print("dlm_rem_lkb_callback empty %x", lkb->lkb_id); 851 list_del_init(&lkb->lkb_cb_list); 852 spin_unlock(&proc->asts_spin); 853 /* removes ref for proc->asts, may cause lkb to be freed */ 854 dlm_put_lkb(lkb); 855 goto try_another; 856 } 857 if (!resid) 858 list_del_init(&lkb->lkb_cb_list); 859 spin_unlock(&proc->asts_spin); 860 861 if (cb.flags & DLM_CB_SKIP) { 862 /* removes ref for proc->asts, may cause lkb to be freed */ 863 if (!resid) 864 dlm_put_lkb(lkb); 865 goto try_another; 866 } 867 868 if (cb.flags & DLM_CB_CAST) { 869 new_mode = cb.mode; 870 871 if (!cb.sb_status && lkb->lkb_lksb->sb_lvbptr && 872 dlm_lvb_operations[old_mode + 1][new_mode + 1]) 873 copy_lvb = 1; 874 875 lkb->lkb_lksb->sb_status = cb.sb_status; 876 lkb->lkb_lksb->sb_flags = cb.sb_flags; 877 } 878 879 rv = copy_result_to_user(lkb->lkb_ua, 880 test_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags), 881 cb.flags, cb.mode, copy_lvb, buf, count); 882 883 /* removes ref for proc->asts, may cause lkb to be freed */ 884 if (!resid) 885 dlm_put_lkb(lkb); 886 887 return rv; 888 } 889 890 static __poll_t device_poll(struct file *file, poll_table *wait) 891 { 892 struct dlm_user_proc *proc = file->private_data; 893 894 poll_wait(file, &proc->wait, wait); 895 896 spin_lock(&proc->asts_spin); 897 if (!list_empty(&proc->asts)) { 898 spin_unlock(&proc->asts_spin); 899 return EPOLLIN | EPOLLRDNORM; 900 } 901 spin_unlock(&proc->asts_spin); 902 return 0; 903 } 904 905 int dlm_user_daemon_available(void) 906 { 907 /* dlm_controld hasn't started (or, has started, but not 908 properly populated configfs) */ 909 910 if (!dlm_our_nodeid()) 911 return 0; 912 913 /* This is to deal with versions of dlm_controld that don't 914 know about the monitor device. We assume that if the 915 dlm_controld was started (above), but the monitor device 916 was never opened, that it's an old version. dlm_controld 917 should open the monitor device before populating configfs. */ 918 919 if (dlm_monitor_unused) 920 return 1; 921 922 return atomic_read(&dlm_monitor_opened) ? 1 : 0; 923 } 924 925 static int ctl_device_open(struct inode *inode, struct file *file) 926 { 927 file->private_data = NULL; 928 return 0; 929 } 930 931 static int ctl_device_close(struct inode *inode, struct file *file) 932 { 933 return 0; 934 } 935 936 static int monitor_device_open(struct inode *inode, struct file *file) 937 { 938 atomic_inc(&dlm_monitor_opened); 939 dlm_monitor_unused = 0; 940 return 0; 941 } 942 943 static int monitor_device_close(struct inode *inode, struct file *file) 944 { 945 if (atomic_dec_and_test(&dlm_monitor_opened)) 946 dlm_stop_lockspaces(); 947 return 0; 948 } 949 950 static const struct file_operations device_fops = { 951 .open = device_open, 952 .release = device_close, 953 .read = device_read, 954 .write = device_write, 955 .poll = device_poll, 956 .owner = THIS_MODULE, 957 .llseek = noop_llseek, 958 }; 959 960 static const struct file_operations ctl_device_fops = { 961 .open = ctl_device_open, 962 .release = ctl_device_close, 963 .read = device_read, 964 .write = device_write, 965 .owner = THIS_MODULE, 966 .llseek = noop_llseek, 967 }; 968 969 static struct miscdevice ctl_device = { 970 .name = "dlm-control", 971 .fops = &ctl_device_fops, 972 .minor = MISC_DYNAMIC_MINOR, 973 }; 974 975 static const struct file_operations monitor_device_fops = { 976 .open = monitor_device_open, 977 .release = monitor_device_close, 978 .owner = THIS_MODULE, 979 .llseek = noop_llseek, 980 }; 981 982 static struct miscdevice monitor_device = { 983 .name = "dlm-monitor", 984 .fops = &monitor_device_fops, 985 .minor = MISC_DYNAMIC_MINOR, 986 }; 987 988 int __init dlm_user_init(void) 989 { 990 int error; 991 992 atomic_set(&dlm_monitor_opened, 0); 993 994 error = misc_register(&ctl_device); 995 if (error) { 996 log_print("misc_register failed for control device"); 997 goto out; 998 } 999 1000 error = misc_register(&monitor_device); 1001 if (error) { 1002 log_print("misc_register failed for monitor device"); 1003 misc_deregister(&ctl_device); 1004 } 1005 out: 1006 return error; 1007 } 1008 1009 void dlm_user_exit(void) 1010 { 1011 misc_deregister(&ctl_device); 1012 misc_deregister(&monitor_device); 1013 } 1014 1015