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