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/smp_lock.h> 19 #include <linux/dlm.h> 20 #include <linux/dlm_device.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 28 static const char name_prefix[] = "dlm"; 29 static const struct file_operations device_fops; 30 31 #ifdef CONFIG_COMPAT 32 33 struct dlm_lock_params32 { 34 __u8 mode; 35 __u8 namelen; 36 __u16 unused; 37 __u32 flags; 38 __u32 lkid; 39 __u32 parent; 40 __u64 xid; 41 __u64 timeout; 42 __u32 castparam; 43 __u32 castaddr; 44 __u32 bastparam; 45 __u32 bastaddr; 46 __u32 lksb; 47 char lvb[DLM_USER_LVB_LEN]; 48 char name[0]; 49 }; 50 51 struct dlm_write_request32 { 52 __u32 version[3]; 53 __u8 cmd; 54 __u8 is64bit; 55 __u8 unused[2]; 56 57 union { 58 struct dlm_lock_params32 lock; 59 struct dlm_lspace_params lspace; 60 struct dlm_purge_params purge; 61 } i; 62 }; 63 64 struct dlm_lksb32 { 65 __u32 sb_status; 66 __u32 sb_lkid; 67 __u8 sb_flags; 68 __u32 sb_lvbptr; 69 }; 70 71 struct dlm_lock_result32 { 72 __u32 version[3]; 73 __u32 length; 74 __u32 user_astaddr; 75 __u32 user_astparam; 76 __u32 user_lksb; 77 struct dlm_lksb32 lksb; 78 __u8 bast_mode; 79 __u8 unused[3]; 80 /* Offsets may be zero if no data is present */ 81 __u32 lvb_offset; 82 }; 83 84 static void compat_input(struct dlm_write_request *kb, 85 struct dlm_write_request32 *kb32, 86 size_t count) 87 { 88 kb->version[0] = kb32->version[0]; 89 kb->version[1] = kb32->version[1]; 90 kb->version[2] = kb32->version[2]; 91 92 kb->cmd = kb32->cmd; 93 kb->is64bit = kb32->is64bit; 94 if (kb->cmd == DLM_USER_CREATE_LOCKSPACE || 95 kb->cmd == DLM_USER_REMOVE_LOCKSPACE) { 96 kb->i.lspace.flags = kb32->i.lspace.flags; 97 kb->i.lspace.minor = kb32->i.lspace.minor; 98 memcpy(kb->i.lspace.name, kb32->i.lspace.name, count - 99 offsetof(struct dlm_write_request32, i.lspace.name)); 100 } else if (kb->cmd == DLM_USER_PURGE) { 101 kb->i.purge.nodeid = kb32->i.purge.nodeid; 102 kb->i.purge.pid = kb32->i.purge.pid; 103 } else { 104 kb->i.lock.mode = kb32->i.lock.mode; 105 kb->i.lock.namelen = kb32->i.lock.namelen; 106 kb->i.lock.flags = kb32->i.lock.flags; 107 kb->i.lock.lkid = kb32->i.lock.lkid; 108 kb->i.lock.parent = kb32->i.lock.parent; 109 kb->i.lock.xid = kb32->i.lock.xid; 110 kb->i.lock.timeout = kb32->i.lock.timeout; 111 kb->i.lock.castparam = (void *)(long)kb32->i.lock.castparam; 112 kb->i.lock.castaddr = (void *)(long)kb32->i.lock.castaddr; 113 kb->i.lock.bastparam = (void *)(long)kb32->i.lock.bastparam; 114 kb->i.lock.bastaddr = (void *)(long)kb32->i.lock.bastaddr; 115 kb->i.lock.lksb = (void *)(long)kb32->i.lock.lksb; 116 memcpy(kb->i.lock.lvb, kb32->i.lock.lvb, DLM_USER_LVB_LEN); 117 memcpy(kb->i.lock.name, kb32->i.lock.name, count - 118 offsetof(struct dlm_write_request32, i.lock.name)); 119 } 120 } 121 122 static void compat_output(struct dlm_lock_result *res, 123 struct dlm_lock_result32 *res32) 124 { 125 res32->version[0] = res->version[0]; 126 res32->version[1] = res->version[1]; 127 res32->version[2] = res->version[2]; 128 129 res32->user_astaddr = (__u32)(long)res->user_astaddr; 130 res32->user_astparam = (__u32)(long)res->user_astparam; 131 res32->user_lksb = (__u32)(long)res->user_lksb; 132 res32->bast_mode = res->bast_mode; 133 134 res32->lvb_offset = res->lvb_offset; 135 res32->length = res->length; 136 137 res32->lksb.sb_status = res->lksb.sb_status; 138 res32->lksb.sb_flags = res->lksb.sb_flags; 139 res32->lksb.sb_lkid = res->lksb.sb_lkid; 140 res32->lksb.sb_lvbptr = (__u32)(long)res->lksb.sb_lvbptr; 141 } 142 #endif 143 144 /* Figure out if this lock is at the end of its life and no longer 145 available for the application to use. The lkb still exists until 146 the final ast is read. A lock becomes EOL in three situations: 147 1. a noqueue request fails with EAGAIN 148 2. an unlock completes with EUNLOCK 149 3. a cancel of a waiting request completes with ECANCEL/EDEADLK 150 An EOL lock needs to be removed from the process's list of locks. 151 And we can't allow any new operation on an EOL lock. This is 152 not related to the lifetime of the lkb struct which is managed 153 entirely by refcount. */ 154 155 static int lkb_is_endoflife(struct dlm_lkb *lkb, int sb_status, int type) 156 { 157 switch (sb_status) { 158 case -DLM_EUNLOCK: 159 return 1; 160 case -DLM_ECANCEL: 161 case -ETIMEDOUT: 162 case -EDEADLK: 163 if (lkb->lkb_grmode == DLM_LOCK_IV) 164 return 1; 165 break; 166 case -EAGAIN: 167 if (type == AST_COMP && lkb->lkb_grmode == DLM_LOCK_IV) 168 return 1; 169 break; 170 } 171 return 0; 172 } 173 174 /* we could possibly check if the cancel of an orphan has resulted in the lkb 175 being removed and then remove that lkb from the orphans list and free it */ 176 177 void dlm_user_add_ast(struct dlm_lkb *lkb, int type) 178 { 179 struct dlm_ls *ls; 180 struct dlm_user_args *ua; 181 struct dlm_user_proc *proc; 182 int eol = 0, ast_type; 183 184 if (lkb->lkb_flags & (DLM_IFL_ORPHAN | DLM_IFL_DEAD)) 185 return; 186 187 ls = lkb->lkb_resource->res_ls; 188 mutex_lock(&ls->ls_clear_proc_locks); 189 190 /* If ORPHAN/DEAD flag is set, it means the process is dead so an ast 191 can't be delivered. For ORPHAN's, dlm_clear_proc_locks() freed 192 lkb->ua so we can't try to use it. This second check is necessary 193 for cases where a completion ast is received for an operation that 194 began before clear_proc_locks did its cancel/unlock. */ 195 196 if (lkb->lkb_flags & (DLM_IFL_ORPHAN | DLM_IFL_DEAD)) 197 goto out; 198 199 DLM_ASSERT(lkb->lkb_ua, dlm_print_lkb(lkb);); 200 ua = lkb->lkb_ua; 201 proc = ua->proc; 202 203 if (type == AST_BAST && ua->bastaddr == NULL) 204 goto out; 205 206 spin_lock(&proc->asts_spin); 207 208 ast_type = lkb->lkb_ast_type; 209 lkb->lkb_ast_type |= type; 210 211 if (!ast_type) { 212 kref_get(&lkb->lkb_ref); 213 list_add_tail(&lkb->lkb_astqueue, &proc->asts); 214 wake_up_interruptible(&proc->wait); 215 } 216 if (type == AST_COMP && (ast_type & AST_COMP)) 217 log_debug(ls, "ast overlap %x status %x %x", 218 lkb->lkb_id, ua->lksb.sb_status, lkb->lkb_flags); 219 220 eol = lkb_is_endoflife(lkb, ua->lksb.sb_status, type); 221 if (eol) { 222 lkb->lkb_ast_type &= ~AST_BAST; 223 lkb->lkb_flags |= DLM_IFL_ENDOFLIFE; 224 } 225 226 /* We want to copy the lvb to userspace when the completion 227 ast is read if the status is 0, the lock has an lvb and 228 lvb_ops says we should. We could probably have set_lvb_lock() 229 set update_user_lvb instead and not need old_mode */ 230 231 if ((lkb->lkb_ast_type & AST_COMP) && 232 (lkb->lkb_lksb->sb_status == 0) && 233 lkb->lkb_lksb->sb_lvbptr && 234 dlm_lvb_operations[ua->old_mode + 1][lkb->lkb_grmode + 1]) 235 ua->update_user_lvb = 1; 236 else 237 ua->update_user_lvb = 0; 238 239 spin_unlock(&proc->asts_spin); 240 241 if (eol) { 242 spin_lock(&proc->locks_spin); 243 if (!list_empty(&lkb->lkb_ownqueue)) { 244 list_del_init(&lkb->lkb_ownqueue); 245 dlm_put_lkb(lkb); 246 } 247 spin_unlock(&proc->locks_spin); 248 } 249 out: 250 mutex_unlock(&ls->ls_clear_proc_locks); 251 } 252 253 static int device_user_lock(struct dlm_user_proc *proc, 254 struct dlm_lock_params *params) 255 { 256 struct dlm_ls *ls; 257 struct dlm_user_args *ua; 258 int error = -ENOMEM; 259 260 ls = dlm_find_lockspace_local(proc->lockspace); 261 if (!ls) 262 return -ENOENT; 263 264 if (!params->castaddr || !params->lksb) { 265 error = -EINVAL; 266 goto out; 267 } 268 269 ua = kzalloc(sizeof(struct dlm_user_args), GFP_KERNEL); 270 if (!ua) 271 goto out; 272 ua->proc = proc; 273 ua->user_lksb = params->lksb; 274 ua->castparam = params->castparam; 275 ua->castaddr = params->castaddr; 276 ua->bastparam = params->bastparam; 277 ua->bastaddr = params->bastaddr; 278 ua->xid = params->xid; 279 280 if (params->flags & DLM_LKF_CONVERT) 281 error = dlm_user_convert(ls, ua, 282 params->mode, params->flags, 283 params->lkid, params->lvb, 284 (unsigned long) params->timeout); 285 else { 286 error = dlm_user_request(ls, ua, 287 params->mode, params->flags, 288 params->name, params->namelen, 289 (unsigned long) params->timeout); 290 if (!error) 291 error = ua->lksb.sb_lkid; 292 } 293 out: 294 dlm_put_lockspace(ls); 295 return error; 296 } 297 298 static int device_user_unlock(struct dlm_user_proc *proc, 299 struct dlm_lock_params *params) 300 { 301 struct dlm_ls *ls; 302 struct dlm_user_args *ua; 303 int error = -ENOMEM; 304 305 ls = dlm_find_lockspace_local(proc->lockspace); 306 if (!ls) 307 return -ENOENT; 308 309 ua = kzalloc(sizeof(struct dlm_user_args), GFP_KERNEL); 310 if (!ua) 311 goto out; 312 ua->proc = proc; 313 ua->user_lksb = params->lksb; 314 ua->castparam = params->castparam; 315 ua->castaddr = params->castaddr; 316 317 if (params->flags & DLM_LKF_CANCEL) 318 error = dlm_user_cancel(ls, ua, params->flags, params->lkid); 319 else 320 error = dlm_user_unlock(ls, ua, params->flags, params->lkid, 321 params->lvb); 322 out: 323 dlm_put_lockspace(ls); 324 return error; 325 } 326 327 static int device_user_deadlock(struct dlm_user_proc *proc, 328 struct dlm_lock_params *params) 329 { 330 struct dlm_ls *ls; 331 int error; 332 333 ls = dlm_find_lockspace_local(proc->lockspace); 334 if (!ls) 335 return -ENOENT; 336 337 error = dlm_user_deadlock(ls, params->flags, params->lkid); 338 339 dlm_put_lockspace(ls); 340 return error; 341 } 342 343 static int create_misc_device(struct dlm_ls *ls, char *name) 344 { 345 int error, len; 346 347 error = -ENOMEM; 348 len = strlen(name) + strlen(name_prefix) + 2; 349 ls->ls_device.name = kzalloc(len, GFP_KERNEL); 350 if (!ls->ls_device.name) 351 goto fail; 352 353 snprintf((char *)ls->ls_device.name, len, "%s_%s", name_prefix, 354 name); 355 ls->ls_device.fops = &device_fops; 356 ls->ls_device.minor = MISC_DYNAMIC_MINOR; 357 358 error = misc_register(&ls->ls_device); 359 if (error) { 360 kfree(ls->ls_device.name); 361 } 362 fail: 363 return error; 364 } 365 366 static int device_user_purge(struct dlm_user_proc *proc, 367 struct dlm_purge_params *params) 368 { 369 struct dlm_ls *ls; 370 int error; 371 372 ls = dlm_find_lockspace_local(proc->lockspace); 373 if (!ls) 374 return -ENOENT; 375 376 error = dlm_user_purge(ls, proc, params->nodeid, params->pid); 377 378 dlm_put_lockspace(ls); 379 return error; 380 } 381 382 static int device_create_lockspace(struct dlm_lspace_params *params) 383 { 384 dlm_lockspace_t *lockspace; 385 struct dlm_ls *ls; 386 int error; 387 388 if (!capable(CAP_SYS_ADMIN)) 389 return -EPERM; 390 391 error = dlm_new_lockspace(params->name, strlen(params->name), 392 &lockspace, params->flags, DLM_USER_LVB_LEN); 393 if (error) 394 return error; 395 396 ls = dlm_find_lockspace_local(lockspace); 397 if (!ls) 398 return -ENOENT; 399 400 error = create_misc_device(ls, params->name); 401 dlm_put_lockspace(ls); 402 403 if (error) 404 dlm_release_lockspace(lockspace, 0); 405 else 406 error = ls->ls_device.minor; 407 408 return error; 409 } 410 411 static int device_remove_lockspace(struct dlm_lspace_params *params) 412 { 413 dlm_lockspace_t *lockspace; 414 struct dlm_ls *ls; 415 int error, force = 0; 416 417 if (!capable(CAP_SYS_ADMIN)) 418 return -EPERM; 419 420 ls = dlm_find_lockspace_device(params->minor); 421 if (!ls) 422 return -ENOENT; 423 424 /* Deregister the misc device first, so we don't have 425 * a device that's not attached to a lockspace. If 426 * dlm_release_lockspace fails then we can recreate it 427 */ 428 error = misc_deregister(&ls->ls_device); 429 if (error) { 430 dlm_put_lockspace(ls); 431 goto out; 432 } 433 kfree(ls->ls_device.name); 434 435 if (params->flags & DLM_USER_LSFLG_FORCEFREE) 436 force = 2; 437 438 lockspace = ls->ls_local_handle; 439 440 /* dlm_release_lockspace waits for references to go to zero, 441 so all processes will need to close their device for the ls 442 before the release will procede */ 443 444 dlm_put_lockspace(ls); 445 error = dlm_release_lockspace(lockspace, force); 446 if (error) 447 create_misc_device(ls, ls->ls_name); 448 out: 449 return error; 450 } 451 452 /* Check the user's version matches ours */ 453 static int check_version(struct dlm_write_request *req) 454 { 455 if (req->version[0] != DLM_DEVICE_VERSION_MAJOR || 456 (req->version[0] == DLM_DEVICE_VERSION_MAJOR && 457 req->version[1] > DLM_DEVICE_VERSION_MINOR)) { 458 459 printk(KERN_DEBUG "dlm: process %s (%d) version mismatch " 460 "user (%d.%d.%d) kernel (%d.%d.%d)\n", 461 current->comm, 462 task_pid_nr(current), 463 req->version[0], 464 req->version[1], 465 req->version[2], 466 DLM_DEVICE_VERSION_MAJOR, 467 DLM_DEVICE_VERSION_MINOR, 468 DLM_DEVICE_VERSION_PATCH); 469 return -EINVAL; 470 } 471 return 0; 472 } 473 474 /* 475 * device_write 476 * 477 * device_user_lock 478 * dlm_user_request -> request_lock 479 * dlm_user_convert -> convert_lock 480 * 481 * device_user_unlock 482 * dlm_user_unlock -> unlock_lock 483 * dlm_user_cancel -> cancel_lock 484 * 485 * device_create_lockspace 486 * dlm_new_lockspace 487 * 488 * device_remove_lockspace 489 * dlm_release_lockspace 490 */ 491 492 /* a write to a lockspace device is a lock or unlock request, a write 493 to the control device is to create/remove a lockspace */ 494 495 static ssize_t device_write(struct file *file, const char __user *buf, 496 size_t count, loff_t *ppos) 497 { 498 struct dlm_user_proc *proc = file->private_data; 499 struct dlm_write_request *kbuf; 500 sigset_t tmpsig, allsigs; 501 int error; 502 503 #ifdef CONFIG_COMPAT 504 if (count < sizeof(struct dlm_write_request32)) 505 #else 506 if (count < sizeof(struct dlm_write_request)) 507 #endif 508 return -EINVAL; 509 510 kbuf = kzalloc(count + 1, GFP_KERNEL); 511 if (!kbuf) 512 return -ENOMEM; 513 514 if (copy_from_user(kbuf, buf, count)) { 515 error = -EFAULT; 516 goto out_free; 517 } 518 519 if (check_version(kbuf)) { 520 error = -EBADE; 521 goto out_free; 522 } 523 524 #ifdef CONFIG_COMPAT 525 if (!kbuf->is64bit) { 526 struct dlm_write_request32 *k32buf; 527 k32buf = (struct dlm_write_request32 *)kbuf; 528 kbuf = kmalloc(count + 1 + (sizeof(struct dlm_write_request) - 529 sizeof(struct dlm_write_request32)), GFP_KERNEL); 530 if (!kbuf) { 531 kfree(k32buf); 532 return -ENOMEM; 533 } 534 535 if (proc) 536 set_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags); 537 compat_input(kbuf, k32buf, count + 1); 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 (proc && test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))) { 545 error = -EINVAL; 546 goto out_free; 547 } 548 549 sigfillset(&allsigs); 550 sigprocmask(SIG_BLOCK, &allsigs, &tmpsig); 551 552 error = -EINVAL; 553 554 switch (kbuf->cmd) 555 { 556 case DLM_USER_LOCK: 557 if (!proc) { 558 log_print("no locking on control device"); 559 goto out_sig; 560 } 561 error = device_user_lock(proc, &kbuf->i.lock); 562 break; 563 564 case DLM_USER_UNLOCK: 565 if (!proc) { 566 log_print("no locking on control device"); 567 goto out_sig; 568 } 569 error = device_user_unlock(proc, &kbuf->i.lock); 570 break; 571 572 case DLM_USER_DEADLOCK: 573 if (!proc) { 574 log_print("no locking on control device"); 575 goto out_sig; 576 } 577 error = device_user_deadlock(proc, &kbuf->i.lock); 578 break; 579 580 case DLM_USER_CREATE_LOCKSPACE: 581 if (proc) { 582 log_print("create/remove only on control device"); 583 goto out_sig; 584 } 585 error = device_create_lockspace(&kbuf->i.lspace); 586 break; 587 588 case DLM_USER_REMOVE_LOCKSPACE: 589 if (proc) { 590 log_print("create/remove only on control device"); 591 goto out_sig; 592 } 593 error = device_remove_lockspace(&kbuf->i.lspace); 594 break; 595 596 case DLM_USER_PURGE: 597 if (!proc) { 598 log_print("no locking on control device"); 599 goto out_sig; 600 } 601 error = device_user_purge(proc, &kbuf->i.purge); 602 break; 603 604 default: 605 log_print("Unknown command passed to DLM device : %d\n", 606 kbuf->cmd); 607 } 608 609 out_sig: 610 sigprocmask(SIG_SETMASK, &tmpsig, NULL); 611 recalc_sigpending(); 612 out_free: 613 kfree(kbuf); 614 return error; 615 } 616 617 /* Every process that opens the lockspace device has its own "proc" structure 618 hanging off the open file that's used to keep track of locks owned by the 619 process and asts that need to be delivered to the process. */ 620 621 static int device_open(struct inode *inode, struct file *file) 622 { 623 struct dlm_user_proc *proc; 624 struct dlm_ls *ls; 625 626 lock_kernel(); 627 ls = dlm_find_lockspace_device(iminor(inode)); 628 if (!ls) { 629 unlock_kernel(); 630 return -ENOENT; 631 } 632 633 proc = kzalloc(sizeof(struct dlm_user_proc), GFP_KERNEL); 634 if (!proc) { 635 dlm_put_lockspace(ls); 636 unlock_kernel(); 637 return -ENOMEM; 638 } 639 640 proc->lockspace = ls->ls_local_handle; 641 INIT_LIST_HEAD(&proc->asts); 642 INIT_LIST_HEAD(&proc->locks); 643 INIT_LIST_HEAD(&proc->unlocking); 644 spin_lock_init(&proc->asts_spin); 645 spin_lock_init(&proc->locks_spin); 646 init_waitqueue_head(&proc->wait); 647 file->private_data = proc; 648 unlock_kernel(); 649 650 return 0; 651 } 652 653 static int device_close(struct inode *inode, struct file *file) 654 { 655 struct dlm_user_proc *proc = file->private_data; 656 struct dlm_ls *ls; 657 sigset_t tmpsig, allsigs; 658 659 ls = dlm_find_lockspace_local(proc->lockspace); 660 if (!ls) 661 return -ENOENT; 662 663 sigfillset(&allsigs); 664 sigprocmask(SIG_BLOCK, &allsigs, &tmpsig); 665 666 set_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags); 667 668 dlm_clear_proc_locks(ls, proc); 669 670 /* at this point no more lkb's should exist for this lockspace, 671 so there's no chance of dlm_user_add_ast() being called and 672 looking for lkb->ua->proc */ 673 674 kfree(proc); 675 file->private_data = NULL; 676 677 dlm_put_lockspace(ls); 678 dlm_put_lockspace(ls); /* for the find in device_open() */ 679 680 /* FIXME: AUTOFREE: if this ls is no longer used do 681 device_remove_lockspace() */ 682 683 sigprocmask(SIG_SETMASK, &tmpsig, NULL); 684 recalc_sigpending(); 685 686 return 0; 687 } 688 689 static int copy_result_to_user(struct dlm_user_args *ua, int compat, int type, 690 int bmode, char __user *buf, size_t count) 691 { 692 #ifdef CONFIG_COMPAT 693 struct dlm_lock_result32 result32; 694 #endif 695 struct dlm_lock_result result; 696 void *resultptr; 697 int error=0; 698 int len; 699 int struct_len; 700 701 memset(&result, 0, sizeof(struct dlm_lock_result)); 702 result.version[0] = DLM_DEVICE_VERSION_MAJOR; 703 result.version[1] = DLM_DEVICE_VERSION_MINOR; 704 result.version[2] = DLM_DEVICE_VERSION_PATCH; 705 memcpy(&result.lksb, &ua->lksb, sizeof(struct dlm_lksb)); 706 result.user_lksb = ua->user_lksb; 707 708 /* FIXME: dlm1 provides for the user's bastparam/addr to not be updated 709 in a conversion unless the conversion is successful. See code 710 in dlm_user_convert() for updating ua from ua_tmp. OpenVMS, though, 711 notes that a new blocking AST address and parameter are set even if 712 the conversion fails, so maybe we should just do that. */ 713 714 if (type == AST_BAST) { 715 result.user_astaddr = ua->bastaddr; 716 result.user_astparam = ua->bastparam; 717 result.bast_mode = bmode; 718 } else { 719 result.user_astaddr = ua->castaddr; 720 result.user_astparam = ua->castparam; 721 } 722 723 #ifdef CONFIG_COMPAT 724 if (compat) 725 len = sizeof(struct dlm_lock_result32); 726 else 727 #endif 728 len = sizeof(struct dlm_lock_result); 729 struct_len = len; 730 731 /* copy lvb to userspace if there is one, it's been updated, and 732 the user buffer has space for it */ 733 734 if (ua->update_user_lvb && ua->lksb.sb_lvbptr && 735 count >= len + DLM_USER_LVB_LEN) { 736 if (copy_to_user(buf+len, ua->lksb.sb_lvbptr, 737 DLM_USER_LVB_LEN)) { 738 error = -EFAULT; 739 goto out; 740 } 741 742 result.lvb_offset = len; 743 len += DLM_USER_LVB_LEN; 744 } 745 746 result.length = len; 747 resultptr = &result; 748 #ifdef CONFIG_COMPAT 749 if (compat) { 750 compat_output(&result, &result32); 751 resultptr = &result32; 752 } 753 #endif 754 755 if (copy_to_user(buf, resultptr, struct_len)) 756 error = -EFAULT; 757 else 758 error = len; 759 out: 760 return error; 761 } 762 763 static int copy_version_to_user(char __user *buf, size_t count) 764 { 765 struct dlm_device_version ver; 766 767 memset(&ver, 0, sizeof(struct dlm_device_version)); 768 ver.version[0] = DLM_DEVICE_VERSION_MAJOR; 769 ver.version[1] = DLM_DEVICE_VERSION_MINOR; 770 ver.version[2] = DLM_DEVICE_VERSION_PATCH; 771 772 if (copy_to_user(buf, &ver, sizeof(struct dlm_device_version))) 773 return -EFAULT; 774 return sizeof(struct dlm_device_version); 775 } 776 777 /* a read returns a single ast described in a struct dlm_lock_result */ 778 779 static ssize_t device_read(struct file *file, char __user *buf, size_t count, 780 loff_t *ppos) 781 { 782 struct dlm_user_proc *proc = file->private_data; 783 struct dlm_lkb *lkb; 784 DECLARE_WAITQUEUE(wait, current); 785 int error, type=0, bmode=0, removed = 0; 786 787 if (count == sizeof(struct dlm_device_version)) { 788 error = copy_version_to_user(buf, count); 789 return error; 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 /* 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 /* there may be both completion and blocking asts to return for 835 the lkb, don't remove lkb from asts list unless no asts remain */ 836 837 lkb = list_entry(proc->asts.next, struct dlm_lkb, lkb_astqueue); 838 839 if (lkb->lkb_ast_type & AST_COMP) { 840 lkb->lkb_ast_type &= ~AST_COMP; 841 type = AST_COMP; 842 } else if (lkb->lkb_ast_type & AST_BAST) { 843 lkb->lkb_ast_type &= ~AST_BAST; 844 type = AST_BAST; 845 bmode = lkb->lkb_bastmode; 846 } 847 848 if (!lkb->lkb_ast_type) { 849 list_del(&lkb->lkb_astqueue); 850 removed = 1; 851 } 852 spin_unlock(&proc->asts_spin); 853 854 error = copy_result_to_user(lkb->lkb_ua, 855 test_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags), 856 type, bmode, buf, count); 857 858 /* removes reference for the proc->asts lists added by 859 dlm_user_add_ast() and may result in the lkb being freed */ 860 if (removed) 861 dlm_put_lkb(lkb); 862 863 return error; 864 } 865 866 static unsigned int device_poll(struct file *file, poll_table *wait) 867 { 868 struct dlm_user_proc *proc = file->private_data; 869 870 poll_wait(file, &proc->wait, wait); 871 872 spin_lock(&proc->asts_spin); 873 if (!list_empty(&proc->asts)) { 874 spin_unlock(&proc->asts_spin); 875 return POLLIN | POLLRDNORM; 876 } 877 spin_unlock(&proc->asts_spin); 878 return 0; 879 } 880 881 static int ctl_device_open(struct inode *inode, struct file *file) 882 { 883 cycle_kernel_lock(); 884 file->private_data = NULL; 885 return 0; 886 } 887 888 static int ctl_device_close(struct inode *inode, struct file *file) 889 { 890 return 0; 891 } 892 893 static const struct file_operations device_fops = { 894 .open = device_open, 895 .release = device_close, 896 .read = device_read, 897 .write = device_write, 898 .poll = device_poll, 899 .owner = THIS_MODULE, 900 }; 901 902 static const struct file_operations ctl_device_fops = { 903 .open = ctl_device_open, 904 .release = ctl_device_close, 905 .read = device_read, 906 .write = device_write, 907 .owner = THIS_MODULE, 908 }; 909 910 static struct miscdevice ctl_device = { 911 .name = "dlm-control", 912 .fops = &ctl_device_fops, 913 .minor = MISC_DYNAMIC_MINOR, 914 }; 915 916 int __init dlm_user_init(void) 917 { 918 int error; 919 920 error = misc_register(&ctl_device); 921 if (error) 922 log_print("misc_register failed for control device"); 923 924 return error; 925 } 926 927 void dlm_user_exit(void) 928 { 929 misc_deregister(&ctl_device); 930 } 931 932