1 /* 2 * Copyright (C) 2006-2007 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 21 #include "dlm_internal.h" 22 #include "lockspace.h" 23 #include "lock.h" 24 #include "lvb_table.h" 25 #include "user.h" 26 27 static const char name_prefix[] = "dlm"; 28 static const struct file_operations device_fops; 29 30 #ifdef CONFIG_COMPAT 31 32 struct dlm_lock_params32 { 33 __u8 mode; 34 __u8 namelen; 35 __u16 unused; 36 __u32 flags; 37 __u32 lkid; 38 __u32 parent; 39 __u64 xid; 40 __u64 timeout; 41 __u32 castparam; 42 __u32 castaddr; 43 __u32 bastparam; 44 __u32 bastaddr; 45 __u32 lksb; 46 char lvb[DLM_USER_LVB_LEN]; 47 char name[0]; 48 }; 49 50 struct dlm_write_request32 { 51 __u32 version[3]; 52 __u8 cmd; 53 __u8 is64bit; 54 __u8 unused[2]; 55 56 union { 57 struct dlm_lock_params32 lock; 58 struct dlm_lspace_params lspace; 59 struct dlm_purge_params purge; 60 } i; 61 }; 62 63 struct dlm_lksb32 { 64 __u32 sb_status; 65 __u32 sb_lkid; 66 __u8 sb_flags; 67 __u32 sb_lvbptr; 68 }; 69 70 struct dlm_lock_result32 { 71 __u32 version[3]; 72 __u32 length; 73 __u32 user_astaddr; 74 __u32 user_astparam; 75 __u32 user_lksb; 76 struct dlm_lksb32 lksb; 77 __u8 bast_mode; 78 __u8 unused[3]; 79 /* Offsets may be zero if no data is present */ 80 __u32 lvb_offset; 81 }; 82 83 static void compat_input(struct dlm_write_request *kb, 84 struct dlm_write_request32 *kb32, 85 int max_namelen) 86 { 87 kb->version[0] = kb32->version[0]; 88 kb->version[1] = kb32->version[1]; 89 kb->version[2] = kb32->version[2]; 90 91 kb->cmd = kb32->cmd; 92 kb->is64bit = kb32->is64bit; 93 if (kb->cmd == DLM_USER_CREATE_LOCKSPACE || 94 kb->cmd == DLM_USER_REMOVE_LOCKSPACE) { 95 kb->i.lspace.flags = kb32->i.lspace.flags; 96 kb->i.lspace.minor = kb32->i.lspace.minor; 97 strcpy(kb->i.lspace.name, kb32->i.lspace.name); 98 } else if (kb->cmd == DLM_USER_PURGE) { 99 kb->i.purge.nodeid = kb32->i.purge.nodeid; 100 kb->i.purge.pid = kb32->i.purge.pid; 101 } else { 102 kb->i.lock.mode = kb32->i.lock.mode; 103 kb->i.lock.namelen = kb32->i.lock.namelen; 104 kb->i.lock.flags = kb32->i.lock.flags; 105 kb->i.lock.lkid = kb32->i.lock.lkid; 106 kb->i.lock.parent = kb32->i.lock.parent; 107 kb->i.lock.xid = kb32->i.lock.xid; 108 kb->i.lock.timeout = kb32->i.lock.timeout; 109 kb->i.lock.castparam = (void *)(long)kb32->i.lock.castparam; 110 kb->i.lock.castaddr = (void *)(long)kb32->i.lock.castaddr; 111 kb->i.lock.bastparam = (void *)(long)kb32->i.lock.bastparam; 112 kb->i.lock.bastaddr = (void *)(long)kb32->i.lock.bastaddr; 113 kb->i.lock.lksb = (void *)(long)kb32->i.lock.lksb; 114 memcpy(kb->i.lock.lvb, kb32->i.lock.lvb, DLM_USER_LVB_LEN); 115 if (kb->i.lock.namelen <= max_namelen) 116 memcpy(kb->i.lock.name, kb32->i.lock.name, 117 kb->i.lock.namelen); 118 else 119 kb->i.lock.namelen = max_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(struct dlm_lkb *lkb, int sb_status, int type) 157 { 158 switch (sb_status) { 159 case -DLM_EUNLOCK: 160 return 1; 161 case -DLM_ECANCEL: 162 case -ETIMEDOUT: 163 case -EDEADLK: 164 if (lkb->lkb_grmode == DLM_LOCK_IV) 165 return 1; 166 break; 167 case -EAGAIN: 168 if (type == AST_COMP && lkb->lkb_grmode == DLM_LOCK_IV) 169 return 1; 170 break; 171 } 172 return 0; 173 } 174 175 /* we could possibly check if the cancel of an orphan has resulted in the lkb 176 being removed and then remove that lkb from the orphans list and free it */ 177 178 void dlm_user_add_ast(struct dlm_lkb *lkb, int type) 179 { 180 struct dlm_ls *ls; 181 struct dlm_user_args *ua; 182 struct dlm_user_proc *proc; 183 int eol = 0, ast_type; 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_astparam, dlm_print_lkb(lkb);); 201 ua = (struct dlm_user_args *)lkb->lkb_astparam; 202 proc = ua->proc; 203 204 if (type == AST_BAST && ua->bastaddr == NULL) 205 goto out; 206 207 spin_lock(&proc->asts_spin); 208 209 ast_type = lkb->lkb_ast_type; 210 lkb->lkb_ast_type |= type; 211 212 if (!ast_type) { 213 kref_get(&lkb->lkb_ref); 214 list_add_tail(&lkb->lkb_astqueue, &proc->asts); 215 wake_up_interruptible(&proc->wait); 216 } 217 if (type == AST_COMP && (ast_type & AST_COMP)) 218 log_debug(ls, "ast overlap %x status %x %x", 219 lkb->lkb_id, ua->lksb.sb_status, lkb->lkb_flags); 220 221 eol = lkb_is_endoflife(lkb, ua->lksb.sb_status, type); 222 if (eol) { 223 lkb->lkb_ast_type &= ~AST_BAST; 224 lkb->lkb_flags |= DLM_IFL_ENDOFLIFE; 225 } 226 227 /* We want to copy the lvb to userspace when the completion 228 ast is read if the status is 0, the lock has an lvb and 229 lvb_ops says we should. We could probably have set_lvb_lock() 230 set update_user_lvb instead and not need old_mode */ 231 232 if ((lkb->lkb_ast_type & AST_COMP) && 233 (lkb->lkb_lksb->sb_status == 0) && 234 lkb->lkb_lksb->sb_lvbptr && 235 dlm_lvb_operations[ua->old_mode + 1][lkb->lkb_grmode + 1]) 236 ua->update_user_lvb = 1; 237 else 238 ua->update_user_lvb = 0; 239 240 spin_unlock(&proc->asts_spin); 241 242 if (eol) { 243 spin_lock(&proc->locks_spin); 244 if (!list_empty(&lkb->lkb_ownqueue)) { 245 list_del_init(&lkb->lkb_ownqueue); 246 dlm_put_lkb(lkb); 247 } 248 spin_unlock(&proc->locks_spin); 249 } 250 out: 251 mutex_unlock(&ls->ls_clear_proc_locks); 252 } 253 254 static int device_user_lock(struct dlm_user_proc *proc, 255 struct dlm_lock_params *params) 256 { 257 struct dlm_ls *ls; 258 struct dlm_user_args *ua; 259 int error = -ENOMEM; 260 261 ls = dlm_find_lockspace_local(proc->lockspace); 262 if (!ls) 263 return -ENOENT; 264 265 if (!params->castaddr || !params->lksb) { 266 error = -EINVAL; 267 goto out; 268 } 269 270 ua = kzalloc(sizeof(struct dlm_user_args), GFP_KERNEL); 271 if (!ua) 272 goto out; 273 ua->proc = proc; 274 ua->user_lksb = params->lksb; 275 ua->castparam = params->castparam; 276 ua->castaddr = params->castaddr; 277 ua->bastparam = params->bastparam; 278 ua->bastaddr = params->bastaddr; 279 ua->xid = params->xid; 280 281 if (params->flags & DLM_LKF_CONVERT) 282 error = dlm_user_convert(ls, ua, 283 params->mode, params->flags, 284 params->lkid, params->lvb, 285 (unsigned long) params->timeout); 286 else { 287 error = dlm_user_request(ls, ua, 288 params->mode, params->flags, 289 params->name, params->namelen, 290 (unsigned long) params->timeout); 291 if (!error) 292 error = ua->lksb.sb_lkid; 293 } 294 out: 295 dlm_put_lockspace(ls); 296 return error; 297 } 298 299 static int device_user_unlock(struct dlm_user_proc *proc, 300 struct dlm_lock_params *params) 301 { 302 struct dlm_ls *ls; 303 struct dlm_user_args *ua; 304 int error = -ENOMEM; 305 306 ls = dlm_find_lockspace_local(proc->lockspace); 307 if (!ls) 308 return -ENOENT; 309 310 ua = kzalloc(sizeof(struct dlm_user_args), GFP_KERNEL); 311 if (!ua) 312 goto out; 313 ua->proc = proc; 314 ua->user_lksb = params->lksb; 315 ua->castparam = params->castparam; 316 ua->castaddr = params->castaddr; 317 318 if (params->flags & DLM_LKF_CANCEL) 319 error = dlm_user_cancel(ls, ua, params->flags, params->lkid); 320 else 321 error = dlm_user_unlock(ls, ua, params->flags, params->lkid, 322 params->lvb); 323 out: 324 dlm_put_lockspace(ls); 325 return error; 326 } 327 328 static int device_user_deadlock(struct dlm_user_proc *proc, 329 struct dlm_lock_params *params) 330 { 331 struct dlm_ls *ls; 332 int error; 333 334 ls = dlm_find_lockspace_local(proc->lockspace); 335 if (!ls) 336 return -ENOENT; 337 338 error = dlm_user_deadlock(ls, params->flags, params->lkid); 339 340 dlm_put_lockspace(ls); 341 return error; 342 } 343 344 static int create_misc_device(struct dlm_ls *ls, char *name) 345 { 346 int error, len; 347 348 error = -ENOMEM; 349 len = strlen(name) + strlen(name_prefix) + 2; 350 ls->ls_device.name = kzalloc(len, GFP_KERNEL); 351 if (!ls->ls_device.name) 352 goto fail; 353 354 snprintf((char *)ls->ls_device.name, len, "%s_%s", name_prefix, 355 name); 356 ls->ls_device.fops = &device_fops; 357 ls->ls_device.minor = MISC_DYNAMIC_MINOR; 358 359 error = misc_register(&ls->ls_device); 360 if (error) { 361 kfree(ls->ls_device.name); 362 } 363 fail: 364 return error; 365 } 366 367 static int device_user_purge(struct dlm_user_proc *proc, 368 struct dlm_purge_params *params) 369 { 370 struct dlm_ls *ls; 371 int error; 372 373 ls = dlm_find_lockspace_local(proc->lockspace); 374 if (!ls) 375 return -ENOENT; 376 377 error = dlm_user_purge(ls, proc, params->nodeid, params->pid); 378 379 dlm_put_lockspace(ls); 380 return error; 381 } 382 383 static int device_create_lockspace(struct dlm_lspace_params *params) 384 { 385 dlm_lockspace_t *lockspace; 386 struct dlm_ls *ls; 387 int error; 388 389 if (!capable(CAP_SYS_ADMIN)) 390 return -EPERM; 391 392 error = dlm_new_lockspace(params->name, strlen(params->name), 393 &lockspace, params->flags, DLM_USER_LVB_LEN); 394 if (error) 395 return error; 396 397 ls = dlm_find_lockspace_local(lockspace); 398 if (!ls) 399 return -ENOENT; 400 401 error = create_misc_device(ls, params->name); 402 dlm_put_lockspace(ls); 403 404 if (error) 405 dlm_release_lockspace(lockspace, 0); 406 else 407 error = ls->ls_device.minor; 408 409 return error; 410 } 411 412 static int device_remove_lockspace(struct dlm_lspace_params *params) 413 { 414 dlm_lockspace_t *lockspace; 415 struct dlm_ls *ls; 416 int error, force = 0; 417 418 if (!capable(CAP_SYS_ADMIN)) 419 return -EPERM; 420 421 ls = dlm_find_lockspace_device(params->minor); 422 if (!ls) 423 return -ENOENT; 424 425 /* Deregister the misc device first, so we don't have 426 * a device that's not attached to a lockspace. If 427 * dlm_release_lockspace fails then we can recreate it 428 */ 429 error = misc_deregister(&ls->ls_device); 430 if (error) { 431 dlm_put_lockspace(ls); 432 goto out; 433 } 434 kfree(ls->ls_device.name); 435 436 if (params->flags & DLM_USER_LSFLG_FORCEFREE) 437 force = 2; 438 439 lockspace = ls->ls_local_handle; 440 441 /* dlm_release_lockspace waits for references to go to zero, 442 so all processes will need to close their device for the ls 443 before the release will procede */ 444 445 dlm_put_lockspace(ls); 446 error = dlm_release_lockspace(lockspace, force); 447 if (error) 448 create_misc_device(ls, ls->ls_name); 449 out: 450 return error; 451 } 452 453 /* Check the user's version matches ours */ 454 static int check_version(struct dlm_write_request *req) 455 { 456 if (req->version[0] != DLM_DEVICE_VERSION_MAJOR || 457 (req->version[0] == DLM_DEVICE_VERSION_MAJOR && 458 req->version[1] > DLM_DEVICE_VERSION_MINOR)) { 459 460 printk(KERN_DEBUG "dlm: process %s (%d) version mismatch " 461 "user (%d.%d.%d) kernel (%d.%d.%d)\n", 462 current->comm, 463 task_pid_nr(current), 464 req->version[0], 465 req->version[1], 466 req->version[2], 467 DLM_DEVICE_VERSION_MAJOR, 468 DLM_DEVICE_VERSION_MINOR, 469 DLM_DEVICE_VERSION_PATCH); 470 return -EINVAL; 471 } 472 return 0; 473 } 474 475 /* 476 * device_write 477 * 478 * device_user_lock 479 * dlm_user_request -> request_lock 480 * dlm_user_convert -> convert_lock 481 * 482 * device_user_unlock 483 * dlm_user_unlock -> unlock_lock 484 * dlm_user_cancel -> cancel_lock 485 * 486 * device_create_lockspace 487 * dlm_new_lockspace 488 * 489 * device_remove_lockspace 490 * dlm_release_lockspace 491 */ 492 493 /* a write to a lockspace device is a lock or unlock request, a write 494 to the control device is to create/remove a lockspace */ 495 496 static ssize_t device_write(struct file *file, const char __user *buf, 497 size_t count, loff_t *ppos) 498 { 499 struct dlm_user_proc *proc = file->private_data; 500 struct dlm_write_request *kbuf; 501 sigset_t tmpsig, allsigs; 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 kbuf = kmalloc(count, GFP_KERNEL); 512 if (!kbuf) 513 return -ENOMEM; 514 515 if (copy_from_user(kbuf, buf, count)) { 516 error = -EFAULT; 517 goto out_free; 518 } 519 520 if (check_version(kbuf)) { 521 error = -EBADE; 522 goto out_free; 523 } 524 525 #ifdef CONFIG_COMPAT 526 if (!kbuf->is64bit) { 527 struct dlm_write_request32 *k32buf; 528 k32buf = (struct dlm_write_request32 *)kbuf; 529 kbuf = kmalloc(count + (sizeof(struct dlm_write_request) - 530 sizeof(struct dlm_write_request32)), GFP_KERNEL); 531 if (!kbuf) 532 return -ENOMEM; 533 534 if (proc) 535 set_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags); 536 compat_input(kbuf, k32buf, 537 count - sizeof(struct dlm_write_request32)); 538 kfree(k32buf); 539 } 540 #endif 541 542 /* do we really need this? can a write happen after a close? */ 543 if ((kbuf->cmd == DLM_USER_LOCK || kbuf->cmd == DLM_USER_UNLOCK) && 544 test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags)) 545 return -EINVAL; 546 547 sigfillset(&allsigs); 548 sigprocmask(SIG_BLOCK, &allsigs, &tmpsig); 549 550 error = -EINVAL; 551 552 switch (kbuf->cmd) 553 { 554 case DLM_USER_LOCK: 555 if (!proc) { 556 log_print("no locking on control device"); 557 goto out_sig; 558 } 559 error = device_user_lock(proc, &kbuf->i.lock); 560 break; 561 562 case DLM_USER_UNLOCK: 563 if (!proc) { 564 log_print("no locking on control device"); 565 goto out_sig; 566 } 567 error = device_user_unlock(proc, &kbuf->i.lock); 568 break; 569 570 case DLM_USER_DEADLOCK: 571 if (!proc) { 572 log_print("no locking on control device"); 573 goto out_sig; 574 } 575 error = device_user_deadlock(proc, &kbuf->i.lock); 576 break; 577 578 case DLM_USER_CREATE_LOCKSPACE: 579 if (proc) { 580 log_print("create/remove only on control device"); 581 goto out_sig; 582 } 583 error = device_create_lockspace(&kbuf->i.lspace); 584 break; 585 586 case DLM_USER_REMOVE_LOCKSPACE: 587 if (proc) { 588 log_print("create/remove only on control device"); 589 goto out_sig; 590 } 591 error = device_remove_lockspace(&kbuf->i.lspace); 592 break; 593 594 case DLM_USER_PURGE: 595 if (!proc) { 596 log_print("no locking on control device"); 597 goto out_sig; 598 } 599 error = device_user_purge(proc, &kbuf->i.purge); 600 break; 601 602 default: 603 log_print("Unknown command passed to DLM device : %d\n", 604 kbuf->cmd); 605 } 606 607 out_sig: 608 sigprocmask(SIG_SETMASK, &tmpsig, NULL); 609 recalc_sigpending(); 610 out_free: 611 kfree(kbuf); 612 return error; 613 } 614 615 /* Every process that opens the lockspace device has its own "proc" structure 616 hanging off the open file that's used to keep track of locks owned by the 617 process and asts that need to be delivered to the process. */ 618 619 static int device_open(struct inode *inode, struct file *file) 620 { 621 struct dlm_user_proc *proc; 622 struct dlm_ls *ls; 623 624 ls = dlm_find_lockspace_device(iminor(inode)); 625 if (!ls) 626 return -ENOENT; 627 628 proc = kzalloc(sizeof(struct dlm_user_proc), GFP_KERNEL); 629 if (!proc) { 630 dlm_put_lockspace(ls); 631 return -ENOMEM; 632 } 633 634 proc->lockspace = ls->ls_local_handle; 635 INIT_LIST_HEAD(&proc->asts); 636 INIT_LIST_HEAD(&proc->locks); 637 INIT_LIST_HEAD(&proc->unlocking); 638 spin_lock_init(&proc->asts_spin); 639 spin_lock_init(&proc->locks_spin); 640 init_waitqueue_head(&proc->wait); 641 file->private_data = proc; 642 643 return 0; 644 } 645 646 static int device_close(struct inode *inode, struct file *file) 647 { 648 struct dlm_user_proc *proc = file->private_data; 649 struct dlm_ls *ls; 650 sigset_t tmpsig, allsigs; 651 652 ls = dlm_find_lockspace_local(proc->lockspace); 653 if (!ls) 654 return -ENOENT; 655 656 sigfillset(&allsigs); 657 sigprocmask(SIG_BLOCK, &allsigs, &tmpsig); 658 659 set_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags); 660 661 dlm_clear_proc_locks(ls, proc); 662 663 /* at this point no more lkb's should exist for this lockspace, 664 so there's no chance of dlm_user_add_ast() being called and 665 looking for lkb->ua->proc */ 666 667 kfree(proc); 668 file->private_data = NULL; 669 670 dlm_put_lockspace(ls); 671 dlm_put_lockspace(ls); /* for the find in device_open() */ 672 673 /* FIXME: AUTOFREE: if this ls is no longer used do 674 device_remove_lockspace() */ 675 676 sigprocmask(SIG_SETMASK, &tmpsig, NULL); 677 recalc_sigpending(); 678 679 return 0; 680 } 681 682 static int copy_result_to_user(struct dlm_user_args *ua, int compat, int type, 683 int bmode, char __user *buf, size_t count) 684 { 685 #ifdef CONFIG_COMPAT 686 struct dlm_lock_result32 result32; 687 #endif 688 struct dlm_lock_result result; 689 void *resultptr; 690 int error=0; 691 int len; 692 int struct_len; 693 694 memset(&result, 0, sizeof(struct dlm_lock_result)); 695 result.version[0] = DLM_DEVICE_VERSION_MAJOR; 696 result.version[1] = DLM_DEVICE_VERSION_MINOR; 697 result.version[2] = DLM_DEVICE_VERSION_PATCH; 698 memcpy(&result.lksb, &ua->lksb, sizeof(struct dlm_lksb)); 699 result.user_lksb = ua->user_lksb; 700 701 /* FIXME: dlm1 provides for the user's bastparam/addr to not be updated 702 in a conversion unless the conversion is successful. See code 703 in dlm_user_convert() for updating ua from ua_tmp. OpenVMS, though, 704 notes that a new blocking AST address and parameter are set even if 705 the conversion fails, so maybe we should just do that. */ 706 707 if (type == AST_BAST) { 708 result.user_astaddr = ua->bastaddr; 709 result.user_astparam = ua->bastparam; 710 result.bast_mode = bmode; 711 } else { 712 result.user_astaddr = ua->castaddr; 713 result.user_astparam = ua->castparam; 714 } 715 716 #ifdef CONFIG_COMPAT 717 if (compat) 718 len = sizeof(struct dlm_lock_result32); 719 else 720 #endif 721 len = sizeof(struct dlm_lock_result); 722 struct_len = len; 723 724 /* copy lvb to userspace if there is one, it's been updated, and 725 the user buffer has space for it */ 726 727 if (ua->update_user_lvb && ua->lksb.sb_lvbptr && 728 count >= len + DLM_USER_LVB_LEN) { 729 if (copy_to_user(buf+len, ua->lksb.sb_lvbptr, 730 DLM_USER_LVB_LEN)) { 731 error = -EFAULT; 732 goto out; 733 } 734 735 result.lvb_offset = len; 736 len += DLM_USER_LVB_LEN; 737 } 738 739 result.length = len; 740 resultptr = &result; 741 #ifdef CONFIG_COMPAT 742 if (compat) { 743 compat_output(&result, &result32); 744 resultptr = &result32; 745 } 746 #endif 747 748 if (copy_to_user(buf, resultptr, struct_len)) 749 error = -EFAULT; 750 else 751 error = len; 752 out: 753 return error; 754 } 755 756 static int copy_version_to_user(char __user *buf, size_t count) 757 { 758 struct dlm_device_version ver; 759 760 memset(&ver, 0, sizeof(struct dlm_device_version)); 761 ver.version[0] = DLM_DEVICE_VERSION_MAJOR; 762 ver.version[1] = DLM_DEVICE_VERSION_MINOR; 763 ver.version[2] = DLM_DEVICE_VERSION_PATCH; 764 765 if (copy_to_user(buf, &ver, sizeof(struct dlm_device_version))) 766 return -EFAULT; 767 return sizeof(struct dlm_device_version); 768 } 769 770 /* a read returns a single ast described in a struct dlm_lock_result */ 771 772 static ssize_t device_read(struct file *file, char __user *buf, size_t count, 773 loff_t *ppos) 774 { 775 struct dlm_user_proc *proc = file->private_data; 776 struct dlm_lkb *lkb; 777 struct dlm_user_args *ua; 778 DECLARE_WAITQUEUE(wait, current); 779 int error, type=0, bmode=0, removed = 0; 780 781 if (count == sizeof(struct dlm_device_version)) { 782 error = copy_version_to_user(buf, count); 783 return error; 784 } 785 786 if (!proc) { 787 log_print("non-version read from control device %zu", count); 788 return -EINVAL; 789 } 790 791 #ifdef CONFIG_COMPAT 792 if (count < sizeof(struct dlm_lock_result32)) 793 #else 794 if (count < sizeof(struct dlm_lock_result)) 795 #endif 796 return -EINVAL; 797 798 /* do we really need this? can a read happen after a close? */ 799 if (test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags)) 800 return -EINVAL; 801 802 spin_lock(&proc->asts_spin); 803 if (list_empty(&proc->asts)) { 804 if (file->f_flags & O_NONBLOCK) { 805 spin_unlock(&proc->asts_spin); 806 return -EAGAIN; 807 } 808 809 add_wait_queue(&proc->wait, &wait); 810 811 repeat: 812 set_current_state(TASK_INTERRUPTIBLE); 813 if (list_empty(&proc->asts) && !signal_pending(current)) { 814 spin_unlock(&proc->asts_spin); 815 schedule(); 816 spin_lock(&proc->asts_spin); 817 goto repeat; 818 } 819 set_current_state(TASK_RUNNING); 820 remove_wait_queue(&proc->wait, &wait); 821 822 if (signal_pending(current)) { 823 spin_unlock(&proc->asts_spin); 824 return -ERESTARTSYS; 825 } 826 } 827 828 /* there may be both completion and blocking asts to return for 829 the lkb, don't remove lkb from asts list unless no asts remain */ 830 831 lkb = list_entry(proc->asts.next, struct dlm_lkb, lkb_astqueue); 832 833 if (lkb->lkb_ast_type & AST_COMP) { 834 lkb->lkb_ast_type &= ~AST_COMP; 835 type = AST_COMP; 836 } else if (lkb->lkb_ast_type & AST_BAST) { 837 lkb->lkb_ast_type &= ~AST_BAST; 838 type = AST_BAST; 839 bmode = lkb->lkb_bastmode; 840 } 841 842 if (!lkb->lkb_ast_type) { 843 list_del(&lkb->lkb_astqueue); 844 removed = 1; 845 } 846 spin_unlock(&proc->asts_spin); 847 848 ua = (struct dlm_user_args *)lkb->lkb_astparam; 849 error = copy_result_to_user(ua, 850 test_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags), 851 type, bmode, buf, count); 852 853 /* removes reference for the proc->asts lists added by 854 dlm_user_add_ast() and may result in the lkb being freed */ 855 if (removed) 856 dlm_put_lkb(lkb); 857 858 return error; 859 } 860 861 static unsigned int device_poll(struct file *file, poll_table *wait) 862 { 863 struct dlm_user_proc *proc = file->private_data; 864 865 poll_wait(file, &proc->wait, wait); 866 867 spin_lock(&proc->asts_spin); 868 if (!list_empty(&proc->asts)) { 869 spin_unlock(&proc->asts_spin); 870 return POLLIN | POLLRDNORM; 871 } 872 spin_unlock(&proc->asts_spin); 873 return 0; 874 } 875 876 static int ctl_device_open(struct inode *inode, struct file *file) 877 { 878 file->private_data = NULL; 879 return 0; 880 } 881 882 static int ctl_device_close(struct inode *inode, struct file *file) 883 { 884 return 0; 885 } 886 887 static const struct file_operations device_fops = { 888 .open = device_open, 889 .release = device_close, 890 .read = device_read, 891 .write = device_write, 892 .poll = device_poll, 893 .owner = THIS_MODULE, 894 }; 895 896 static const struct file_operations ctl_device_fops = { 897 .open = ctl_device_open, 898 .release = ctl_device_close, 899 .read = device_read, 900 .write = device_write, 901 .owner = THIS_MODULE, 902 }; 903 904 static struct miscdevice ctl_device = { 905 .name = "dlm-control", 906 .fops = &ctl_device_fops, 907 .minor = MISC_DYNAMIC_MINOR, 908 }; 909 910 int dlm_user_init(void) 911 { 912 int error; 913 914 error = misc_register(&ctl_device); 915 if (error) 916 log_print("misc_register failed for control device"); 917 918 return error; 919 } 920 921 void dlm_user_exit(void) 922 { 923 misc_deregister(&ctl_device); 924 } 925 926