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 int error = -ENOMEM; 242 243 ls = dlm_find_lockspace_local(proc->lockspace); 244 if (!ls) 245 return -ENOENT; 246 247 if (!params->castaddr || !params->lksb) { 248 error = -EINVAL; 249 goto out; 250 } 251 252 ua = kzalloc(sizeof(struct dlm_user_args), GFP_NOFS); 253 if (!ua) 254 goto out; 255 ua->proc = proc; 256 ua->user_lksb = params->lksb; 257 ua->castparam = params->castparam; 258 ua->castaddr = params->castaddr; 259 ua->bastparam = params->bastparam; 260 ua->bastaddr = params->bastaddr; 261 ua->xid = params->xid; 262 263 if (params->flags & DLM_LKF_CONVERT) 264 error = dlm_user_convert(ls, ua, 265 params->mode, params->flags, 266 params->lkid, params->lvb, 267 (unsigned long) params->timeout); 268 else { 269 error = dlm_user_request(ls, ua, 270 params->mode, params->flags, 271 params->name, params->namelen, 272 (unsigned long) params->timeout); 273 if (!error) 274 error = ua->lksb.sb_lkid; 275 } 276 out: 277 dlm_put_lockspace(ls); 278 return error; 279 } 280 281 static int device_user_unlock(struct dlm_user_proc *proc, 282 struct dlm_lock_params *params) 283 { 284 struct dlm_ls *ls; 285 struct dlm_user_args *ua; 286 int error = -ENOMEM; 287 288 ls = dlm_find_lockspace_local(proc->lockspace); 289 if (!ls) 290 return -ENOENT; 291 292 ua = kzalloc(sizeof(struct dlm_user_args), GFP_NOFS); 293 if (!ua) 294 goto out; 295 ua->proc = proc; 296 ua->user_lksb = params->lksb; 297 ua->castparam = params->castparam; 298 ua->castaddr = params->castaddr; 299 300 if (params->flags & DLM_LKF_CANCEL) 301 error = dlm_user_cancel(ls, ua, params->flags, params->lkid); 302 else 303 error = dlm_user_unlock(ls, ua, params->flags, params->lkid, 304 params->lvb); 305 out: 306 dlm_put_lockspace(ls); 307 return error; 308 } 309 310 static int device_user_deadlock(struct dlm_user_proc *proc, 311 struct dlm_lock_params *params) 312 { 313 struct dlm_ls *ls; 314 int error; 315 316 ls = dlm_find_lockspace_local(proc->lockspace); 317 if (!ls) 318 return -ENOENT; 319 320 error = dlm_user_deadlock(ls, params->flags, params->lkid); 321 322 dlm_put_lockspace(ls); 323 return error; 324 } 325 326 static int dlm_device_register(struct dlm_ls *ls, char *name) 327 { 328 int error, len; 329 330 /* The device is already registered. This happens when the 331 lockspace is created multiple times from userspace. */ 332 if (ls->ls_device.name) 333 return 0; 334 335 error = -ENOMEM; 336 len = strlen(name) + strlen(name_prefix) + 2; 337 ls->ls_device.name = kzalloc(len, GFP_NOFS); 338 if (!ls->ls_device.name) 339 goto fail; 340 341 snprintf((char *)ls->ls_device.name, len, "%s_%s", name_prefix, 342 name); 343 ls->ls_device.fops = &device_fops; 344 ls->ls_device.minor = MISC_DYNAMIC_MINOR; 345 346 error = misc_register(&ls->ls_device); 347 if (error) { 348 kfree(ls->ls_device.name); 349 } 350 fail: 351 return error; 352 } 353 354 int dlm_device_deregister(struct dlm_ls *ls) 355 { 356 int error; 357 358 /* The device is not registered. This happens when the lockspace 359 was never used from userspace, or when device_create_lockspace() 360 calls dlm_release_lockspace() after the register fails. */ 361 if (!ls->ls_device.name) 362 return 0; 363 364 error = misc_deregister(&ls->ls_device); 365 if (!error) 366 kfree(ls->ls_device.name); 367 return error; 368 } 369 370 static int device_user_purge(struct dlm_user_proc *proc, 371 struct dlm_purge_params *params) 372 { 373 struct dlm_ls *ls; 374 int error; 375 376 ls = dlm_find_lockspace_local(proc->lockspace); 377 if (!ls) 378 return -ENOENT; 379 380 error = dlm_user_purge(ls, proc, params->nodeid, params->pid); 381 382 dlm_put_lockspace(ls); 383 return error; 384 } 385 386 static int device_create_lockspace(struct dlm_lspace_params *params) 387 { 388 dlm_lockspace_t *lockspace; 389 struct dlm_ls *ls; 390 int error; 391 392 if (!capable(CAP_SYS_ADMIN)) 393 return -EPERM; 394 395 error = dlm_new_lockspace(params->name, NULL, params->flags, 396 DLM_USER_LVB_LEN, NULL, NULL, NULL, 397 &lockspace); 398 if (error) 399 return error; 400 401 ls = dlm_find_lockspace_local(lockspace); 402 if (!ls) 403 return -ENOENT; 404 405 error = dlm_device_register(ls, params->name); 406 dlm_put_lockspace(ls); 407 408 if (error) 409 dlm_release_lockspace(lockspace, 0); 410 else 411 error = ls->ls_device.minor; 412 413 return error; 414 } 415 416 static int device_remove_lockspace(struct dlm_lspace_params *params) 417 { 418 dlm_lockspace_t *lockspace; 419 struct dlm_ls *ls; 420 int error, force = 0; 421 422 if (!capable(CAP_SYS_ADMIN)) 423 return -EPERM; 424 425 ls = dlm_find_lockspace_device(params->minor); 426 if (!ls) 427 return -ENOENT; 428 429 if (params->flags & DLM_USER_LSFLG_FORCEFREE) 430 force = 2; 431 432 lockspace = ls->ls_local_handle; 433 dlm_put_lockspace(ls); 434 435 /* The final dlm_release_lockspace waits for references to go to 436 zero, so all processes will need to close their device for the 437 ls before the release will proceed. release also calls the 438 device_deregister above. Converting a positive return value 439 from release to zero means that userspace won't know when its 440 release was the final one, but it shouldn't need to know. */ 441 442 error = dlm_release_lockspace(lockspace, force); 443 if (error > 0) 444 error = 0; 445 return error; 446 } 447 448 /* Check the user's version matches ours */ 449 static int check_version(struct dlm_write_request *req) 450 { 451 if (req->version[0] != DLM_DEVICE_VERSION_MAJOR || 452 (req->version[0] == DLM_DEVICE_VERSION_MAJOR && 453 req->version[1] > DLM_DEVICE_VERSION_MINOR)) { 454 455 printk(KERN_DEBUG "dlm: process %s (%d) version mismatch " 456 "user (%d.%d.%d) kernel (%d.%d.%d)\n", 457 current->comm, 458 task_pid_nr(current), 459 req->version[0], 460 req->version[1], 461 req->version[2], 462 DLM_DEVICE_VERSION_MAJOR, 463 DLM_DEVICE_VERSION_MINOR, 464 DLM_DEVICE_VERSION_PATCH); 465 return -EINVAL; 466 } 467 return 0; 468 } 469 470 /* 471 * device_write 472 * 473 * device_user_lock 474 * dlm_user_request -> request_lock 475 * dlm_user_convert -> convert_lock 476 * 477 * device_user_unlock 478 * dlm_user_unlock -> unlock_lock 479 * dlm_user_cancel -> cancel_lock 480 * 481 * device_create_lockspace 482 * dlm_new_lockspace 483 * 484 * device_remove_lockspace 485 * dlm_release_lockspace 486 */ 487 488 /* a write to a lockspace device is a lock or unlock request, a write 489 to the control device is to create/remove a lockspace */ 490 491 static ssize_t device_write(struct file *file, const char __user *buf, 492 size_t count, loff_t *ppos) 493 { 494 struct dlm_user_proc *proc = file->private_data; 495 struct dlm_write_request *kbuf; 496 sigset_t tmpsig, allsigs; 497 int error; 498 499 #ifdef CONFIG_COMPAT 500 if (count < sizeof(struct dlm_write_request32)) 501 #else 502 if (count < sizeof(struct dlm_write_request)) 503 #endif 504 return -EINVAL; 505 506 /* 507 * can't compare against COMPAT/dlm_write_request32 because 508 * we don't yet know if is64bit is zero 509 */ 510 if (count > sizeof(struct dlm_write_request) + DLM_RESNAME_MAXLEN) 511 return -EINVAL; 512 513 kbuf = kzalloc(count + 1, GFP_NOFS); 514 if (!kbuf) 515 return -ENOMEM; 516 517 if (copy_from_user(kbuf, buf, count)) { 518 error = -EFAULT; 519 goto out_free; 520 } 521 522 if (check_version(kbuf)) { 523 error = -EBADE; 524 goto out_free; 525 } 526 527 #ifdef CONFIG_COMPAT 528 if (!kbuf->is64bit) { 529 struct dlm_write_request32 *k32buf; 530 int namelen = 0; 531 532 if (count > sizeof(struct dlm_write_request32)) 533 namelen = count - sizeof(struct dlm_write_request32); 534 535 k32buf = (struct dlm_write_request32 *)kbuf; 536 537 /* add 1 after namelen so that the name string is terminated */ 538 kbuf = kzalloc(sizeof(struct dlm_write_request) + namelen + 1, 539 GFP_NOFS); 540 if (!kbuf) { 541 kfree(k32buf); 542 return -ENOMEM; 543 } 544 545 if (proc) 546 set_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags); 547 548 compat_input(kbuf, k32buf, namelen); 549 kfree(k32buf); 550 } 551 #endif 552 553 /* do we really need this? can a write happen after a close? */ 554 if ((kbuf->cmd == DLM_USER_LOCK || kbuf->cmd == DLM_USER_UNLOCK) && 555 (proc && test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))) { 556 error = -EINVAL; 557 goto out_free; 558 } 559 560 sigfillset(&allsigs); 561 sigprocmask(SIG_BLOCK, &allsigs, &tmpsig); 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_sig; 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_sig; 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_sig; 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_sig; 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_sig; 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_sig; 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_sig: 621 sigprocmask(SIG_SETMASK, &tmpsig, NULL); 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 sigset_t tmpsig, allsigs; 663 664 ls = dlm_find_lockspace_local(proc->lockspace); 665 if (!ls) 666 return -ENOENT; 667 668 sigfillset(&allsigs); 669 sigprocmask(SIG_BLOCK, &allsigs, &tmpsig); 670 671 set_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags); 672 673 dlm_clear_proc_locks(ls, proc); 674 675 /* at this point no more lkb's should exist for this lockspace, 676 so there's no chance of dlm_user_add_ast() being called and 677 looking for lkb->ua->proc */ 678 679 kfree(proc); 680 file->private_data = NULL; 681 682 dlm_put_lockspace(ls); 683 dlm_put_lockspace(ls); /* for the find in device_open() */ 684 685 /* FIXME: AUTOFREE: if this ls is no longer used do 686 device_remove_lockspace() */ 687 688 sigprocmask(SIG_SETMASK, &tmpsig, NULL); 689 recalc_sigpending(); 690 691 return 0; 692 } 693 694 static int copy_result_to_user(struct dlm_user_args *ua, int compat, 695 uint32_t flags, int mode, int copy_lvb, 696 char __user *buf, size_t count) 697 { 698 #ifdef CONFIG_COMPAT 699 struct dlm_lock_result32 result32; 700 #endif 701 struct dlm_lock_result result; 702 void *resultptr; 703 int error=0; 704 int len; 705 int struct_len; 706 707 memset(&result, 0, sizeof(struct dlm_lock_result)); 708 result.version[0] = DLM_DEVICE_VERSION_MAJOR; 709 result.version[1] = DLM_DEVICE_VERSION_MINOR; 710 result.version[2] = DLM_DEVICE_VERSION_PATCH; 711 memcpy(&result.lksb, &ua->lksb, sizeof(struct dlm_lksb)); 712 result.user_lksb = ua->user_lksb; 713 714 /* FIXME: dlm1 provides for the user's bastparam/addr to not be updated 715 in a conversion unless the conversion is successful. See code 716 in dlm_user_convert() for updating ua from ua_tmp. OpenVMS, though, 717 notes that a new blocking AST address and parameter are set even if 718 the conversion fails, so maybe we should just do that. */ 719 720 if (flags & DLM_CB_BAST) { 721 result.user_astaddr = ua->bastaddr; 722 result.user_astparam = ua->bastparam; 723 result.bast_mode = mode; 724 } else { 725 result.user_astaddr = ua->castaddr; 726 result.user_astparam = ua->castparam; 727 } 728 729 #ifdef CONFIG_COMPAT 730 if (compat) 731 len = sizeof(struct dlm_lock_result32); 732 else 733 #endif 734 len = sizeof(struct dlm_lock_result); 735 struct_len = len; 736 737 /* copy lvb to userspace if there is one, it's been updated, and 738 the user buffer has space for it */ 739 740 if (copy_lvb && ua->lksb.sb_lvbptr && count >= len + DLM_USER_LVB_LEN) { 741 if (copy_to_user(buf+len, ua->lksb.sb_lvbptr, 742 DLM_USER_LVB_LEN)) { 743 error = -EFAULT; 744 goto out; 745 } 746 747 result.lvb_offset = len; 748 len += DLM_USER_LVB_LEN; 749 } 750 751 result.length = len; 752 resultptr = &result; 753 #ifdef CONFIG_COMPAT 754 if (compat) { 755 compat_output(&result, &result32); 756 resultptr = &result32; 757 } 758 #endif 759 760 if (copy_to_user(buf, resultptr, struct_len)) 761 error = -EFAULT; 762 else 763 error = len; 764 out: 765 return error; 766 } 767 768 static int copy_version_to_user(char __user *buf, size_t count) 769 { 770 struct dlm_device_version ver; 771 772 memset(&ver, 0, sizeof(struct dlm_device_version)); 773 ver.version[0] = DLM_DEVICE_VERSION_MAJOR; 774 ver.version[1] = DLM_DEVICE_VERSION_MINOR; 775 ver.version[2] = DLM_DEVICE_VERSION_PATCH; 776 777 if (copy_to_user(buf, &ver, sizeof(struct dlm_device_version))) 778 return -EFAULT; 779 return sizeof(struct dlm_device_version); 780 } 781 782 /* a read returns a single ast described in a struct dlm_lock_result */ 783 784 static ssize_t device_read(struct file *file, char __user *buf, size_t count, 785 loff_t *ppos) 786 { 787 struct dlm_user_proc *proc = file->private_data; 788 struct dlm_lkb *lkb; 789 DECLARE_WAITQUEUE(wait, current); 790 struct dlm_callback cb; 791 int rv, resid, copy_lvb = 0; 792 793 if (count == sizeof(struct dlm_device_version)) { 794 rv = copy_version_to_user(buf, count); 795 return rv; 796 } 797 798 if (!proc) { 799 log_print("non-version read from control device %zu", count); 800 return -EINVAL; 801 } 802 803 #ifdef CONFIG_COMPAT 804 if (count < sizeof(struct dlm_lock_result32)) 805 #else 806 if (count < sizeof(struct dlm_lock_result)) 807 #endif 808 return -EINVAL; 809 810 try_another: 811 812 /* do we really need this? can a read happen after a close? */ 813 if (test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags)) 814 return -EINVAL; 815 816 spin_lock(&proc->asts_spin); 817 if (list_empty(&proc->asts)) { 818 if (file->f_flags & O_NONBLOCK) { 819 spin_unlock(&proc->asts_spin); 820 return -EAGAIN; 821 } 822 823 add_wait_queue(&proc->wait, &wait); 824 825 repeat: 826 set_current_state(TASK_INTERRUPTIBLE); 827 if (list_empty(&proc->asts) && !signal_pending(current)) { 828 spin_unlock(&proc->asts_spin); 829 schedule(); 830 spin_lock(&proc->asts_spin); 831 goto repeat; 832 } 833 set_current_state(TASK_RUNNING); 834 remove_wait_queue(&proc->wait, &wait); 835 836 if (signal_pending(current)) { 837 spin_unlock(&proc->asts_spin); 838 return -ERESTARTSYS; 839 } 840 } 841 842 /* if we empty lkb_callbacks, we don't want to unlock the spinlock 843 without removing lkb_cb_list; so empty lkb_cb_list is always 844 consistent with empty lkb_callbacks */ 845 846 lkb = list_entry(proc->asts.next, struct dlm_lkb, lkb_cb_list); 847 848 rv = dlm_rem_lkb_callback(lkb->lkb_resource->res_ls, lkb, &cb, &resid); 849 if (rv < 0) { 850 /* this shouldn't happen; lkb should have been removed from 851 list when resid was zero */ 852 log_print("dlm_rem_lkb_callback empty %x", lkb->lkb_id); 853 list_del_init(&lkb->lkb_cb_list); 854 spin_unlock(&proc->asts_spin); 855 /* removes ref for proc->asts, may cause lkb to be freed */ 856 dlm_put_lkb(lkb); 857 goto try_another; 858 } 859 if (!resid) 860 list_del_init(&lkb->lkb_cb_list); 861 spin_unlock(&proc->asts_spin); 862 863 if (cb.flags & DLM_CB_SKIP) { 864 /* removes ref for proc->asts, may cause lkb to be freed */ 865 if (!resid) 866 dlm_put_lkb(lkb); 867 goto try_another; 868 } 869 870 if (cb.flags & DLM_CB_CAST) { 871 int old_mode, new_mode; 872 873 old_mode = lkb->lkb_last_cast.mode; 874 new_mode = cb.mode; 875 876 if (!cb.sb_status && lkb->lkb_lksb->sb_lvbptr && 877 dlm_lvb_operations[old_mode + 1][new_mode + 1]) 878 copy_lvb = 1; 879 880 lkb->lkb_lksb->sb_status = cb.sb_status; 881 lkb->lkb_lksb->sb_flags = cb.sb_flags; 882 } 883 884 rv = copy_result_to_user(lkb->lkb_ua, 885 test_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags), 886 cb.flags, cb.mode, copy_lvb, buf, count); 887 888 /* removes ref for proc->asts, may cause lkb to be freed */ 889 if (!resid) 890 dlm_put_lkb(lkb); 891 892 return rv; 893 } 894 895 static unsigned int device_poll(struct file *file, poll_table *wait) 896 { 897 struct dlm_user_proc *proc = file->private_data; 898 899 poll_wait(file, &proc->wait, wait); 900 901 spin_lock(&proc->asts_spin); 902 if (!list_empty(&proc->asts)) { 903 spin_unlock(&proc->asts_spin); 904 return POLLIN | POLLRDNORM; 905 } 906 spin_unlock(&proc->asts_spin); 907 return 0; 908 } 909 910 int dlm_user_daemon_available(void) 911 { 912 /* dlm_controld hasn't started (or, has started, but not 913 properly populated configfs) */ 914 915 if (!dlm_our_nodeid()) 916 return 0; 917 918 /* This is to deal with versions of dlm_controld that don't 919 know about the monitor device. We assume that if the 920 dlm_controld was started (above), but the monitor device 921 was never opened, that it's an old version. dlm_controld 922 should open the monitor device before populating configfs. */ 923 924 if (dlm_monitor_unused) 925 return 1; 926 927 return atomic_read(&dlm_monitor_opened) ? 1 : 0; 928 } 929 930 static int ctl_device_open(struct inode *inode, struct file *file) 931 { 932 file->private_data = NULL; 933 return 0; 934 } 935 936 static int ctl_device_close(struct inode *inode, struct file *file) 937 { 938 return 0; 939 } 940 941 static int monitor_device_open(struct inode *inode, struct file *file) 942 { 943 atomic_inc(&dlm_monitor_opened); 944 dlm_monitor_unused = 0; 945 return 0; 946 } 947 948 static int monitor_device_close(struct inode *inode, struct file *file) 949 { 950 if (atomic_dec_and_test(&dlm_monitor_opened)) 951 dlm_stop_lockspaces(); 952 return 0; 953 } 954 955 static const struct file_operations device_fops = { 956 .open = device_open, 957 .release = device_close, 958 .read = device_read, 959 .write = device_write, 960 .poll = device_poll, 961 .owner = THIS_MODULE, 962 .llseek = noop_llseek, 963 }; 964 965 static const struct file_operations ctl_device_fops = { 966 .open = ctl_device_open, 967 .release = ctl_device_close, 968 .read = device_read, 969 .write = device_write, 970 .owner = THIS_MODULE, 971 .llseek = noop_llseek, 972 }; 973 974 static struct miscdevice ctl_device = { 975 .name = "dlm-control", 976 .fops = &ctl_device_fops, 977 .minor = MISC_DYNAMIC_MINOR, 978 }; 979 980 static const struct file_operations monitor_device_fops = { 981 .open = monitor_device_open, 982 .release = monitor_device_close, 983 .owner = THIS_MODULE, 984 .llseek = noop_llseek, 985 }; 986 987 static struct miscdevice monitor_device = { 988 .name = "dlm-monitor", 989 .fops = &monitor_device_fops, 990 .minor = MISC_DYNAMIC_MINOR, 991 }; 992 993 int __init dlm_user_init(void) 994 { 995 int error; 996 997 atomic_set(&dlm_monitor_opened, 0); 998 999 error = misc_register(&ctl_device); 1000 if (error) { 1001 log_print("misc_register failed for control device"); 1002 goto out; 1003 } 1004 1005 error = misc_register(&monitor_device); 1006 if (error) { 1007 log_print("misc_register failed for monitor device"); 1008 misc_deregister(&ctl_device); 1009 } 1010 out: 1011 return error; 1012 } 1013 1014 void dlm_user_exit(void) 1015 { 1016 misc_deregister(&ctl_device); 1017 misc_deregister(&monitor_device); 1018 } 1019 1020