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, strlen(params->name), 396 &lockspace, params->flags, DLM_USER_LVB_LEN); 397 if (error) 398 return error; 399 400 ls = dlm_find_lockspace_local(lockspace); 401 if (!ls) 402 return -ENOENT; 403 404 error = dlm_device_register(ls, params->name); 405 dlm_put_lockspace(ls); 406 407 if (error) 408 dlm_release_lockspace(lockspace, 0); 409 else 410 error = ls->ls_device.minor; 411 412 return error; 413 } 414 415 static int device_remove_lockspace(struct dlm_lspace_params *params) 416 { 417 dlm_lockspace_t *lockspace; 418 struct dlm_ls *ls; 419 int error, force = 0; 420 421 if (!capable(CAP_SYS_ADMIN)) 422 return -EPERM; 423 424 ls = dlm_find_lockspace_device(params->minor); 425 if (!ls) 426 return -ENOENT; 427 428 if (params->flags & DLM_USER_LSFLG_FORCEFREE) 429 force = 2; 430 431 lockspace = ls->ls_local_handle; 432 dlm_put_lockspace(ls); 433 434 /* The final dlm_release_lockspace waits for references to go to 435 zero, so all processes will need to close their device for the 436 ls before the release will proceed. release also calls the 437 device_deregister above. Converting a positive return value 438 from release to zero means that userspace won't know when its 439 release was the final one, but it shouldn't need to know. */ 440 441 error = dlm_release_lockspace(lockspace, force); 442 if (error > 0) 443 error = 0; 444 return error; 445 } 446 447 /* Check the user's version matches ours */ 448 static int check_version(struct dlm_write_request *req) 449 { 450 if (req->version[0] != DLM_DEVICE_VERSION_MAJOR || 451 (req->version[0] == DLM_DEVICE_VERSION_MAJOR && 452 req->version[1] > DLM_DEVICE_VERSION_MINOR)) { 453 454 printk(KERN_DEBUG "dlm: process %s (%d) version mismatch " 455 "user (%d.%d.%d) kernel (%d.%d.%d)\n", 456 current->comm, 457 task_pid_nr(current), 458 req->version[0], 459 req->version[1], 460 req->version[2], 461 DLM_DEVICE_VERSION_MAJOR, 462 DLM_DEVICE_VERSION_MINOR, 463 DLM_DEVICE_VERSION_PATCH); 464 return -EINVAL; 465 } 466 return 0; 467 } 468 469 /* 470 * device_write 471 * 472 * device_user_lock 473 * dlm_user_request -> request_lock 474 * dlm_user_convert -> convert_lock 475 * 476 * device_user_unlock 477 * dlm_user_unlock -> unlock_lock 478 * dlm_user_cancel -> cancel_lock 479 * 480 * device_create_lockspace 481 * dlm_new_lockspace 482 * 483 * device_remove_lockspace 484 * dlm_release_lockspace 485 */ 486 487 /* a write to a lockspace device is a lock or unlock request, a write 488 to the control device is to create/remove a lockspace */ 489 490 static ssize_t device_write(struct file *file, const char __user *buf, 491 size_t count, loff_t *ppos) 492 { 493 struct dlm_user_proc *proc = file->private_data; 494 struct dlm_write_request *kbuf; 495 sigset_t tmpsig, allsigs; 496 int error; 497 498 #ifdef CONFIG_COMPAT 499 if (count < sizeof(struct dlm_write_request32)) 500 #else 501 if (count < sizeof(struct dlm_write_request)) 502 #endif 503 return -EINVAL; 504 505 kbuf = kzalloc(count + 1, GFP_NOFS); 506 if (!kbuf) 507 return -ENOMEM; 508 509 if (copy_from_user(kbuf, buf, count)) { 510 error = -EFAULT; 511 goto out_free; 512 } 513 514 if (check_version(kbuf)) { 515 error = -EBADE; 516 goto out_free; 517 } 518 519 #ifdef CONFIG_COMPAT 520 if (!kbuf->is64bit) { 521 struct dlm_write_request32 *k32buf; 522 int namelen = 0; 523 524 if (count > sizeof(struct dlm_write_request32)) 525 namelen = count - sizeof(struct dlm_write_request32); 526 527 k32buf = (struct dlm_write_request32 *)kbuf; 528 529 /* add 1 after namelen so that the name string is terminated */ 530 kbuf = kzalloc(sizeof(struct dlm_write_request) + namelen + 1, 531 GFP_NOFS); 532 if (!kbuf) { 533 kfree(k32buf); 534 return -ENOMEM; 535 } 536 537 if (proc) 538 set_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags); 539 540 compat_input(kbuf, k32buf, namelen); 541 kfree(k32buf); 542 } 543 #endif 544 545 /* do we really need this? can a write happen after a close? */ 546 if ((kbuf->cmd == DLM_USER_LOCK || kbuf->cmd == DLM_USER_UNLOCK) && 547 (proc && test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))) { 548 error = -EINVAL; 549 goto out_free; 550 } 551 552 sigfillset(&allsigs); 553 sigprocmask(SIG_BLOCK, &allsigs, &tmpsig); 554 555 error = -EINVAL; 556 557 switch (kbuf->cmd) 558 { 559 case DLM_USER_LOCK: 560 if (!proc) { 561 log_print("no locking on control device"); 562 goto out_sig; 563 } 564 error = device_user_lock(proc, &kbuf->i.lock); 565 break; 566 567 case DLM_USER_UNLOCK: 568 if (!proc) { 569 log_print("no locking on control device"); 570 goto out_sig; 571 } 572 error = device_user_unlock(proc, &kbuf->i.lock); 573 break; 574 575 case DLM_USER_DEADLOCK: 576 if (!proc) { 577 log_print("no locking on control device"); 578 goto out_sig; 579 } 580 error = device_user_deadlock(proc, &kbuf->i.lock); 581 break; 582 583 case DLM_USER_CREATE_LOCKSPACE: 584 if (proc) { 585 log_print("create/remove only on control device"); 586 goto out_sig; 587 } 588 error = device_create_lockspace(&kbuf->i.lspace); 589 break; 590 591 case DLM_USER_REMOVE_LOCKSPACE: 592 if (proc) { 593 log_print("create/remove only on control device"); 594 goto out_sig; 595 } 596 error = device_remove_lockspace(&kbuf->i.lspace); 597 break; 598 599 case DLM_USER_PURGE: 600 if (!proc) { 601 log_print("no locking on control device"); 602 goto out_sig; 603 } 604 error = device_user_purge(proc, &kbuf->i.purge); 605 break; 606 607 default: 608 log_print("Unknown command passed to DLM device : %d\n", 609 kbuf->cmd); 610 } 611 612 out_sig: 613 sigprocmask(SIG_SETMASK, &tmpsig, NULL); 614 out_free: 615 kfree(kbuf); 616 return error; 617 } 618 619 /* Every process that opens the lockspace device has its own "proc" structure 620 hanging off the open file that's used to keep track of locks owned by the 621 process and asts that need to be delivered to the process. */ 622 623 static int device_open(struct inode *inode, struct file *file) 624 { 625 struct dlm_user_proc *proc; 626 struct dlm_ls *ls; 627 628 ls = dlm_find_lockspace_device(iminor(inode)); 629 if (!ls) 630 return -ENOENT; 631 632 proc = kzalloc(sizeof(struct dlm_user_proc), GFP_NOFS); 633 if (!proc) { 634 dlm_put_lockspace(ls); 635 return -ENOMEM; 636 } 637 638 proc->lockspace = ls->ls_local_handle; 639 INIT_LIST_HEAD(&proc->asts); 640 INIT_LIST_HEAD(&proc->locks); 641 INIT_LIST_HEAD(&proc->unlocking); 642 spin_lock_init(&proc->asts_spin); 643 spin_lock_init(&proc->locks_spin); 644 init_waitqueue_head(&proc->wait); 645 file->private_data = proc; 646 647 return 0; 648 } 649 650 static int device_close(struct inode *inode, struct file *file) 651 { 652 struct dlm_user_proc *proc = file->private_data; 653 struct dlm_ls *ls; 654 sigset_t tmpsig, allsigs; 655 656 ls = dlm_find_lockspace_local(proc->lockspace); 657 if (!ls) 658 return -ENOENT; 659 660 sigfillset(&allsigs); 661 sigprocmask(SIG_BLOCK, &allsigs, &tmpsig); 662 663 set_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags); 664 665 dlm_clear_proc_locks(ls, proc); 666 667 /* at this point no more lkb's should exist for this lockspace, 668 so there's no chance of dlm_user_add_ast() being called and 669 looking for lkb->ua->proc */ 670 671 kfree(proc); 672 file->private_data = NULL; 673 674 dlm_put_lockspace(ls); 675 dlm_put_lockspace(ls); /* for the find in device_open() */ 676 677 /* FIXME: AUTOFREE: if this ls is no longer used do 678 device_remove_lockspace() */ 679 680 sigprocmask(SIG_SETMASK, &tmpsig, NULL); 681 recalc_sigpending(); 682 683 return 0; 684 } 685 686 static int copy_result_to_user(struct dlm_user_args *ua, int compat, 687 uint32_t flags, int mode, int copy_lvb, 688 char __user *buf, size_t count) 689 { 690 #ifdef CONFIG_COMPAT 691 struct dlm_lock_result32 result32; 692 #endif 693 struct dlm_lock_result result; 694 void *resultptr; 695 int error=0; 696 int len; 697 int struct_len; 698 699 memset(&result, 0, sizeof(struct dlm_lock_result)); 700 result.version[0] = DLM_DEVICE_VERSION_MAJOR; 701 result.version[1] = DLM_DEVICE_VERSION_MINOR; 702 result.version[2] = DLM_DEVICE_VERSION_PATCH; 703 memcpy(&result.lksb, &ua->lksb, sizeof(struct dlm_lksb)); 704 result.user_lksb = ua->user_lksb; 705 706 /* FIXME: dlm1 provides for the user's bastparam/addr to not be updated 707 in a conversion unless the conversion is successful. See code 708 in dlm_user_convert() for updating ua from ua_tmp. OpenVMS, though, 709 notes that a new blocking AST address and parameter are set even if 710 the conversion fails, so maybe we should just do that. */ 711 712 if (flags & DLM_CB_BAST) { 713 result.user_astaddr = ua->bastaddr; 714 result.user_astparam = ua->bastparam; 715 result.bast_mode = mode; 716 } else { 717 result.user_astaddr = ua->castaddr; 718 result.user_astparam = ua->castparam; 719 } 720 721 #ifdef CONFIG_COMPAT 722 if (compat) 723 len = sizeof(struct dlm_lock_result32); 724 else 725 #endif 726 len = sizeof(struct dlm_lock_result); 727 struct_len = len; 728 729 /* copy lvb to userspace if there is one, it's been updated, and 730 the user buffer has space for it */ 731 732 if (copy_lvb && ua->lksb.sb_lvbptr && count >= len + DLM_USER_LVB_LEN) { 733 if (copy_to_user(buf+len, ua->lksb.sb_lvbptr, 734 DLM_USER_LVB_LEN)) { 735 error = -EFAULT; 736 goto out; 737 } 738 739 result.lvb_offset = len; 740 len += DLM_USER_LVB_LEN; 741 } 742 743 result.length = len; 744 resultptr = &result; 745 #ifdef CONFIG_COMPAT 746 if (compat) { 747 compat_output(&result, &result32); 748 resultptr = &result32; 749 } 750 #endif 751 752 if (copy_to_user(buf, resultptr, struct_len)) 753 error = -EFAULT; 754 else 755 error = len; 756 out: 757 return error; 758 } 759 760 static int copy_version_to_user(char __user *buf, size_t count) 761 { 762 struct dlm_device_version ver; 763 764 memset(&ver, 0, sizeof(struct dlm_device_version)); 765 ver.version[0] = DLM_DEVICE_VERSION_MAJOR; 766 ver.version[1] = DLM_DEVICE_VERSION_MINOR; 767 ver.version[2] = DLM_DEVICE_VERSION_PATCH; 768 769 if (copy_to_user(buf, &ver, sizeof(struct dlm_device_version))) 770 return -EFAULT; 771 return sizeof(struct dlm_device_version); 772 } 773 774 /* a read returns a single ast described in a struct dlm_lock_result */ 775 776 static ssize_t device_read(struct file *file, char __user *buf, size_t count, 777 loff_t *ppos) 778 { 779 struct dlm_user_proc *proc = file->private_data; 780 struct dlm_lkb *lkb; 781 DECLARE_WAITQUEUE(wait, current); 782 struct dlm_callback cb; 783 int rv, resid, copy_lvb = 0; 784 785 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 rv = dlm_rem_lkb_callback(lkb->lkb_resource->res_ls, lkb, &cb, &resid); 841 if (rv < 0) { 842 /* this shouldn't happen; lkb should have been removed from 843 list when resid was zero */ 844 log_print("dlm_rem_lkb_callback empty %x", lkb->lkb_id); 845 list_del_init(&lkb->lkb_cb_list); 846 spin_unlock(&proc->asts_spin); 847 /* removes ref for proc->asts, may cause lkb to be freed */ 848 dlm_put_lkb(lkb); 849 goto try_another; 850 } 851 if (!resid) 852 list_del_init(&lkb->lkb_cb_list); 853 spin_unlock(&proc->asts_spin); 854 855 if (cb.flags & DLM_CB_SKIP) { 856 /* removes ref for proc->asts, may cause lkb to be freed */ 857 if (!resid) 858 dlm_put_lkb(lkb); 859 goto try_another; 860 } 861 862 if (cb.flags & DLM_CB_CAST) { 863 int old_mode, new_mode; 864 865 old_mode = lkb->lkb_last_cast.mode; 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 unsigned int 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 POLLIN | POLLRDNORM; 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