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 27static const char *name_prefix="dlm"; 28static struct miscdevice ctl_device; 29static const struct file_operations device_fops; 30 31#ifdef CONFIG_COMPAT 32 33struct dlm_lock_params32 { 34 __u8 mode; 35 __u8 namelen; 36 __u16 flags; 37 __u32 lkid; 38 __u32 parent; 39 40 __u32 castparam; 41 __u32 castaddr; 42 __u32 bastparam; 43 __u32 bastaddr; 44 __u32 lksb; 45 46 char lvb[DLM_USER_LVB_LEN]; 47 char name[0]; 48}; 49 50struct 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 63struct dlm_lksb32 { 64 __u32 sb_status; 65 __u32 sb_lkid; 66 __u8 sb_flags; 67 __u32 sb_lvbptr; 68}; 69 70struct dlm_lock_result32 { 71 __u32 length; 72 __u32 user_astaddr; 73 __u32 user_astparam; 74 __u32 user_lksb; 75 struct dlm_lksb32 lksb; 76 __u8 bast_mode; 77 __u8 unused[3]; 78 /* Offsets may be zero if no data is present */ 79 __u32 lvb_offset; 80}; 81 82static void compat_input(struct dlm_write_request *kb, 83 struct dlm_write_request32 *kb32) 84{ 85 kb->version[0] = kb32->version[0]; 86 kb->version[1] = kb32->version[1]; 87 kb->version[2] = kb32->version[2]; 88 89 kb->cmd = kb32->cmd; 90 kb->is64bit = kb32->is64bit; 91 if (kb->cmd == DLM_USER_CREATE_LOCKSPACE || 92 kb->cmd == DLM_USER_REMOVE_LOCKSPACE) { 93 kb->i.lspace.flags = kb32->i.lspace.flags; 94 kb->i.lspace.minor = kb32->i.lspace.minor; 95 strcpy(kb->i.lspace.name, kb32->i.lspace.name); 96 } else if (kb->cmd == DLM_USER_PURGE) { 97 kb->i.purge.nodeid = kb32->i.purge.nodeid; 98 kb->i.purge.pid = kb32->i.purge.pid; 99 } else { 100 kb->i.lock.mode = kb32->i.lock.mode; 101 kb->i.lock.namelen = kb32->i.lock.namelen; 102 kb->i.lock.flags = kb32->i.lock.flags; 103 kb->i.lock.lkid = kb32->i.lock.lkid; 104 kb->i.lock.parent = kb32->i.lock.parent; 105 kb->i.lock.castparam = (void *)(long)kb32->i.lock.castparam; 106 kb->i.lock.castaddr = (void *)(long)kb32->i.lock.castaddr; 107 kb->i.lock.bastparam = (void *)(long)kb32->i.lock.bastparam; 108 kb->i.lock.bastaddr = (void *)(long)kb32->i.lock.bastaddr; 109 kb->i.lock.lksb = (void *)(long)kb32->i.lock.lksb; 110 memcpy(kb->i.lock.lvb, kb32->i.lock.lvb, DLM_USER_LVB_LEN); 111 memcpy(kb->i.lock.name, kb32->i.lock.name, kb->i.lock.namelen); 112 } 113} 114 115static void compat_output(struct dlm_lock_result *res, 116 struct dlm_lock_result32 *res32) 117{ 118 res32->user_astaddr = (__u32)(long)res->user_astaddr; 119 res32->user_astparam = (__u32)(long)res->user_astparam; 120 res32->user_lksb = (__u32)(long)res->user_lksb; 121 res32->bast_mode = res->bast_mode; 122 123 res32->lvb_offset = res->lvb_offset; 124 res32->length = res->length; 125 126 res32->lksb.sb_status = res->lksb.sb_status; 127 res32->lksb.sb_flags = res->lksb.sb_flags; 128 res32->lksb.sb_lkid = res->lksb.sb_lkid; 129 res32->lksb.sb_lvbptr = (__u32)(long)res->lksb.sb_lvbptr; 130} 131#endif 132 133/* we could possibly check if the cancel of an orphan has resulted in the lkb 134 being removed and then remove that lkb from the orphans list and free it */ 135 136void dlm_user_add_ast(struct dlm_lkb *lkb, int type) 137{ 138 struct dlm_ls *ls; 139 struct dlm_user_args *ua; 140 struct dlm_user_proc *proc; 141 int eol = 0, ast_type; 142 143 if (lkb->lkb_flags & (DLM_IFL_ORPHAN | DLM_IFL_DEAD)) 144 return; 145 146 ls = lkb->lkb_resource->res_ls; 147 mutex_lock(&ls->ls_clear_proc_locks); 148 149 /* If ORPHAN/DEAD flag is set, it means the process is dead so an ast 150 can't be delivered. For ORPHAN's, dlm_clear_proc_locks() freed 151 lkb->ua so we can't try to use it. This second check is necessary 152 for cases where a completion ast is received for an operation that 153 began before clear_proc_locks did its cancel/unlock. */ 154 155 if (lkb->lkb_flags & (DLM_IFL_ORPHAN | DLM_IFL_DEAD)) 156 goto out; 157 158 DLM_ASSERT(lkb->lkb_astparam, dlm_print_lkb(lkb);); 159 ua = (struct dlm_user_args *)lkb->lkb_astparam; 160 proc = ua->proc; 161 162 if (type == AST_BAST && ua->bastaddr == NULL) 163 goto out; 164 165 spin_lock(&proc->asts_spin); 166 167 ast_type = lkb->lkb_ast_type; 168 lkb->lkb_ast_type |= type; 169 170 if (!ast_type) { 171 kref_get(&lkb->lkb_ref); 172 list_add_tail(&lkb->lkb_astqueue, &proc->asts); 173 wake_up_interruptible(&proc->wait); 174 } 175 if (type == AST_COMP && (ast_type & AST_COMP)) 176 log_debug(ls, "ast overlap %x status %x %x", 177 lkb->lkb_id, ua->lksb.sb_status, lkb->lkb_flags); 178 179 /* Figure out if this lock is at the end of its life and no longer 180 available for the application to use. The lkb still exists until 181 the final ast is read. A lock becomes EOL in three situations: 182 1. a noqueue request fails with EAGAIN 183 2. an unlock completes with EUNLOCK 184 3. a cancel of a waiting request completes with ECANCEL 185 An EOL lock needs to be removed from the process's list of locks. 186 And we can't allow any new operation on an EOL lock. This is 187 not related to the lifetime of the lkb struct which is managed 188 entirely by refcount. */ 189 190 if (type == AST_COMP && 191 lkb->lkb_grmode == DLM_LOCK_IV && 192 ua->lksb.sb_status == -EAGAIN) 193 eol = 1; 194 else if (ua->lksb.sb_status == -DLM_EUNLOCK || 195 (ua->lksb.sb_status == -DLM_ECANCEL && 196 lkb->lkb_grmode == DLM_LOCK_IV)) 197 eol = 1; 198 if (eol) { 199 lkb->lkb_ast_type &= ~AST_BAST; 200 lkb->lkb_flags |= DLM_IFL_ENDOFLIFE; 201 } 202 203 /* We want to copy the lvb to userspace when the completion 204 ast is read if the status is 0, the lock has an lvb and 205 lvb_ops says we should. We could probably have set_lvb_lock() 206 set update_user_lvb instead and not need old_mode */ 207 208 if ((lkb->lkb_ast_type & AST_COMP) && 209 (lkb->lkb_lksb->sb_status == 0) && 210 lkb->lkb_lksb->sb_lvbptr && 211 dlm_lvb_operations[ua->old_mode + 1][lkb->lkb_grmode + 1]) 212 ua->update_user_lvb = 1; 213 else 214 ua->update_user_lvb = 0; 215 216 spin_unlock(&proc->asts_spin); 217 218 if (eol) { 219 spin_lock(&ua->proc->locks_spin); 220 if (!list_empty(&lkb->lkb_ownqueue)) { 221 list_del_init(&lkb->lkb_ownqueue); 222 dlm_put_lkb(lkb); 223 } 224 spin_unlock(&ua->proc->locks_spin); 225 } 226 out: 227 mutex_unlock(&ls->ls_clear_proc_locks); 228} 229 230static int device_user_lock(struct dlm_user_proc *proc, 231 struct dlm_lock_params *params) 232{ 233 struct dlm_ls *ls; 234 struct dlm_user_args *ua; 235 int error = -ENOMEM; 236 237 ls = dlm_find_lockspace_local(proc->lockspace); 238 if (!ls) 239 return -ENOENT; 240 241 if (!params->castaddr || !params->lksb) { 242 error = -EINVAL; 243 goto out; 244 } 245 246 ua = kzalloc(sizeof(struct dlm_user_args), GFP_KERNEL); 247 if (!ua) 248 goto out; 249 ua->proc = proc; 250 ua->user_lksb = params->lksb; 251 ua->castparam = params->castparam; 252 ua->castaddr = params->castaddr; 253 ua->bastparam = params->bastparam; 254 ua->bastaddr = params->bastaddr; 255 256 if (params->flags & DLM_LKF_CONVERT) 257 error = dlm_user_convert(ls, ua, 258 params->mode, params->flags, 259 params->lkid, params->lvb); 260 else { 261 error = dlm_user_request(ls, ua, 262 params->mode, params->flags, 263 params->name, params->namelen, 264 params->parent); 265 if (!error) 266 error = ua->lksb.sb_lkid; 267 } 268 out: 269 dlm_put_lockspace(ls); 270 return error; 271} 272 273static int device_user_unlock(struct dlm_user_proc *proc, 274 struct dlm_lock_params *params) 275{ 276 struct dlm_ls *ls; 277 struct dlm_user_args *ua; 278 int error = -ENOMEM; 279 280 ls = dlm_find_lockspace_local(proc->lockspace); 281 if (!ls) 282 return -ENOENT; 283 284 ua = kzalloc(sizeof(struct dlm_user_args), GFP_KERNEL); 285 if (!ua) 286 goto out; 287 ua->proc = proc; 288 ua->user_lksb = params->lksb; 289 ua->castparam = params->castparam; 290 ua->castaddr = params->castaddr; 291 292 if (params->flags & DLM_LKF_CANCEL) 293 error = dlm_user_cancel(ls, ua, params->flags, params->lkid); 294 else 295 error = dlm_user_unlock(ls, ua, params->flags, params->lkid, 296 params->lvb); 297 out: 298 dlm_put_lockspace(ls); 299 return error; 300} 301 302static int create_misc_device(struct dlm_ls *ls, char *name) 303{ 304 int error, len; 305 306 error = -ENOMEM; 307 len = strlen(name) + strlen(name_prefix) + 2; 308 ls->ls_device.name = kzalloc(len, GFP_KERNEL); 309 if (!ls->ls_device.name) 310 goto fail; 311 312 snprintf((char *)ls->ls_device.name, len, "%s_%s", name_prefix, 313 name); 314 ls->ls_device.fops = &device_fops; 315 ls->ls_device.minor = MISC_DYNAMIC_MINOR; 316 317 error = misc_register(&ls->ls_device); 318 if (error) { 319 kfree(ls->ls_device.name); 320 } 321fail: 322 return error; 323} 324 325static int device_user_purge(struct dlm_user_proc *proc, 326 struct dlm_purge_params *params) 327{ 328 struct dlm_ls *ls; 329 int error; 330 331 ls = dlm_find_lockspace_local(proc->lockspace); 332 if (!ls) 333 return -ENOENT; 334 335 error = dlm_user_purge(ls, proc, params->nodeid, params->pid); 336 337 dlm_put_lockspace(ls); 338 return error; 339} 340 341static int device_create_lockspace(struct dlm_lspace_params *params) 342{ 343 dlm_lockspace_t *lockspace; 344 struct dlm_ls *ls; 345 int error; 346 347 if (!capable(CAP_SYS_ADMIN)) 348 return -EPERM; 349 350 error = dlm_new_lockspace(params->name, strlen(params->name), 351 &lockspace, 0, DLM_USER_LVB_LEN); 352 if (error) 353 return error; 354 355 ls = dlm_find_lockspace_local(lockspace); 356 if (!ls) 357 return -ENOENT; 358 359 error = create_misc_device(ls, params->name); 360 dlm_put_lockspace(ls); 361 362 if (error) 363 dlm_release_lockspace(lockspace, 0); 364 else 365 error = ls->ls_device.minor; 366 367 return error; 368} 369 370static int device_remove_lockspace(struct dlm_lspace_params *params) 371{ 372 dlm_lockspace_t *lockspace; 373 struct dlm_ls *ls; 374 int error, force = 0; 375 376 if (!capable(CAP_SYS_ADMIN)) 377 return -EPERM; 378 379 ls = dlm_find_lockspace_device(params->minor); 380 if (!ls) 381 return -ENOENT; 382 383 /* Deregister the misc device first, so we don't have 384 * a device that's not attached to a lockspace. If 385 * dlm_release_lockspace fails then we can recreate it 386 */ 387 error = misc_deregister(&ls->ls_device); 388 if (error) { 389 dlm_put_lockspace(ls); 390 goto out; 391 } 392 kfree(ls->ls_device.name); 393 394 if (params->flags & DLM_USER_LSFLG_FORCEFREE) 395 force = 2; 396 397 lockspace = ls->ls_local_handle; 398 399 /* dlm_release_lockspace waits for references to go to zero, 400 so all processes will need to close their device for the ls 401 before the release will procede */ 402 403 dlm_put_lockspace(ls); 404 error = dlm_release_lockspace(lockspace, force); 405 if (error) 406 create_misc_device(ls, ls->ls_name); 407 out: 408 return error; 409} 410 411/* Check the user's version matches ours */ 412static int check_version(struct dlm_write_request *req) 413{ 414 if (req->version[0] != DLM_DEVICE_VERSION_MAJOR || 415 (req->version[0] == DLM_DEVICE_VERSION_MAJOR && 416 req->version[1] > DLM_DEVICE_VERSION_MINOR)) { 417 418 printk(KERN_DEBUG "dlm: process %s (%d) version mismatch " 419 "user (%d.%d.%d) kernel (%d.%d.%d)\n", 420 current->comm, 421 current->pid, 422 req->version[0], 423 req->version[1], 424 req->version[2], 425 DLM_DEVICE_VERSION_MAJOR, 426 DLM_DEVICE_VERSION_MINOR, 427 DLM_DEVICE_VERSION_PATCH); 428 return -EINVAL; 429 } 430 return 0; 431} 432 433/* 434 * device_write 435 * 436 * device_user_lock 437 * dlm_user_request -> request_lock 438 * dlm_user_convert -> convert_lock 439 * 440 * device_user_unlock 441 * dlm_user_unlock -> unlock_lock 442 * dlm_user_cancel -> cancel_lock 443 * 444 * device_create_lockspace 445 * dlm_new_lockspace 446 * 447 * device_remove_lockspace 448 * dlm_release_lockspace 449 */ 450 451/* a write to a lockspace device is a lock or unlock request, a write 452 to the control device is to create/remove a lockspace */ 453 454static ssize_t device_write(struct file *file, const char __user *buf, 455 size_t count, loff_t *ppos) 456{ 457 struct dlm_user_proc *proc = file->private_data; 458 struct dlm_write_request *kbuf; 459 sigset_t tmpsig, allsigs; 460 int error; 461 462#ifdef CONFIG_COMPAT 463 if (count < sizeof(struct dlm_write_request32)) 464#else 465 if (count < sizeof(struct dlm_write_request)) 466#endif 467 return -EINVAL; 468 469 kbuf = kmalloc(count, GFP_KERNEL); 470 if (!kbuf) 471 return -ENOMEM; 472 473 if (copy_from_user(kbuf, buf, count)) { 474 error = -EFAULT; 475 goto out_free; 476 } 477 478 if (check_version(kbuf)) { 479 error = -EBADE; 480 goto out_free; 481 } 482 483#ifdef CONFIG_COMPAT 484 if (!kbuf->is64bit) { 485 struct dlm_write_request32 *k32buf; 486 k32buf = (struct dlm_write_request32 *)kbuf; 487 kbuf = kmalloc(count + (sizeof(struct dlm_write_request) - 488 sizeof(struct dlm_write_request32)), GFP_KERNEL); 489 if (!kbuf) 490 return -ENOMEM; 491 492 if (proc) 493 set_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags); 494 compat_input(kbuf, k32buf); 495 kfree(k32buf); 496 } 497#endif 498 499 /* do we really need this? can a write happen after a close? */ 500 if ((kbuf->cmd == DLM_USER_LOCK || kbuf->cmd == DLM_USER_UNLOCK) && 501 test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags)) 502 return -EINVAL; 503 504 sigfillset(&allsigs); 505 sigprocmask(SIG_BLOCK, &allsigs, &tmpsig); 506 507 error = -EINVAL; 508 509 switch (kbuf->cmd) 510 { 511 case DLM_USER_LOCK: 512 if (!proc) { 513 log_print("no locking on control device"); 514 goto out_sig; 515 } 516 error = device_user_lock(proc, &kbuf->i.lock); 517 break; 518 519 case DLM_USER_UNLOCK: 520 if (!proc) { 521 log_print("no locking on control device"); 522 goto out_sig; 523 } 524 error = device_user_unlock(proc, &kbuf->i.lock); 525 break; 526 527 case DLM_USER_CREATE_LOCKSPACE: 528 if (proc) { 529 log_print("create/remove only on control device"); 530 goto out_sig; 531 } 532 error = device_create_lockspace(&kbuf->i.lspace); 533 break; 534 535 case DLM_USER_REMOVE_LOCKSPACE: 536 if (proc) { 537 log_print("create/remove only on control device"); 538 goto out_sig; 539 } 540 error = device_remove_lockspace(&kbuf->i.lspace); 541 break; 542 543 case DLM_USER_PURGE: 544 if (!proc) { 545 log_print("no locking on control device"); 546 goto out_sig; 547 } 548 error = device_user_purge(proc, &kbuf->i.purge); 549 break; 550 551 default: 552 log_print("Unknown command passed to DLM device : %d\n", 553 kbuf->cmd); 554 } 555 556 out_sig: 557 sigprocmask(SIG_SETMASK, &tmpsig, NULL); 558 recalc_sigpending(); 559 out_free: 560 kfree(kbuf); 561 return error; 562} 563 564/* Every process that opens the lockspace device has its own "proc" structure 565 hanging off the open file that's used to keep track of locks owned by the 566 process and asts that need to be delivered to the process. */ 567 568static int device_open(struct inode *inode, struct file *file) 569{ 570 struct dlm_user_proc *proc; 571 struct dlm_ls *ls; 572 573 ls = dlm_find_lockspace_device(iminor(inode)); 574 if (!ls) 575 return -ENOENT; 576 577 proc = kzalloc(sizeof(struct dlm_user_proc), GFP_KERNEL); 578 if (!proc) { 579 dlm_put_lockspace(ls); 580 return -ENOMEM; 581 } 582 583 proc->lockspace = ls->ls_local_handle; 584 INIT_LIST_HEAD(&proc->asts); 585 INIT_LIST_HEAD(&proc->locks); 586 INIT_LIST_HEAD(&proc->unlocking); 587 spin_lock_init(&proc->asts_spin); 588 spin_lock_init(&proc->locks_spin); 589 init_waitqueue_head(&proc->wait); 590 file->private_data = proc; 591 592 return 0; 593} 594 595static int device_close(struct inode *inode, struct file *file) 596{ 597 struct dlm_user_proc *proc = file->private_data; 598 struct dlm_ls *ls; 599 sigset_t tmpsig, allsigs; 600 601 ls = dlm_find_lockspace_local(proc->lockspace); 602 if (!ls) 603 return -ENOENT; 604 605 sigfillset(&allsigs); 606 sigprocmask(SIG_BLOCK, &allsigs, &tmpsig); 607 608 set_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags); 609 610 dlm_clear_proc_locks(ls, proc); 611 612 /* at this point no more lkb's should exist for this lockspace, 613 so there's no chance of dlm_user_add_ast() being called and 614 looking for lkb->ua->proc */ 615 616 kfree(proc); 617 file->private_data = NULL; 618 619 dlm_put_lockspace(ls); 620 dlm_put_lockspace(ls); /* for the find in device_open() */ 621 622 623 sigprocmask(SIG_SETMASK, &tmpsig, NULL); 624 recalc_sigpending(); 625 626 return 0; 627} 628 629static int copy_result_to_user(struct dlm_user_args *ua, int compat, int type, 630 int bmode, char __user *buf, size_t count) 631{ 632#ifdef CONFIG_COMPAT 633 struct dlm_lock_result32 result32; 634#endif 635 struct dlm_lock_result result; 636 void *resultptr; 637 int error=0; 638 int len; 639 int struct_len; 640 641 memset(&result, 0, sizeof(struct dlm_lock_result)); 642 memcpy(&result.lksb, &ua->lksb, sizeof(struct dlm_lksb)); 643 result.user_lksb = ua->user_lksb; 644 645 646 if (type == AST_BAST) { 647 result.user_astaddr = ua->bastaddr; 648 result.user_astparam = ua->bastparam; 649 result.bast_mode = bmode; 650 } else { 651 result.user_astaddr = ua->castaddr; 652 result.user_astparam = ua->castparam; 653 } 654 655#ifdef CONFIG_COMPAT 656 if (compat) 657 len = sizeof(struct dlm_lock_result32); 658 else 659#endif 660 len = sizeof(struct dlm_lock_result); 661 struct_len = len; 662 663 /* copy lvb to userspace if there is one, it's been updated, and 664 the user buffer has space for it */ 665 666 if (ua->update_user_lvb && ua->lksb.sb_lvbptr && 667 count >= len + DLM_USER_LVB_LEN) { 668 if (copy_to_user(buf+len, ua->lksb.sb_lvbptr, 669 DLM_USER_LVB_LEN)) { 670 error = -EFAULT; 671 goto out; 672 } 673 674 result.lvb_offset = len; 675 len += DLM_USER_LVB_LEN; 676 } 677 678 result.length = len; 679 resultptr = &result; 680#ifdef CONFIG_COMPAT 681 if (compat) { 682 compat_output(&result, &result32); 683 resultptr = &result32; 684 } 685#endif 686 687 if (copy_to_user(buf, resultptr, struct_len)) 688 error = -EFAULT; 689 else 690 error = len; 691 out: 692 return error; 693} 694 695/* a read returns a single ast described in a struct dlm_lock_result */ 696 697static ssize_t device_read(struct file *file, char __user *buf, size_t count, 698 loff_t *ppos) 699{ 700 struct dlm_user_proc *proc = file->private_data; 701 struct dlm_lkb *lkb; 702 struct dlm_user_args *ua; 703 DECLARE_WAITQUEUE(wait, current); 704 int error, type=0, bmode=0, removed = 0; 705 706#ifdef CONFIG_COMPAT 707 if (count < sizeof(struct dlm_lock_result32)) 708#else 709 if (count < sizeof(struct dlm_lock_result)) 710#endif 711 return -EINVAL; 712 713 /* do we really need this? can a read happen after a close? */ 714 if (test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags)) 715 return -EINVAL; 716 717 spin_lock(&proc->asts_spin); 718 if (list_empty(&proc->asts)) { 719 if (file->f_flags & O_NONBLOCK) { 720 spin_unlock(&proc->asts_spin); 721 return -EAGAIN; 722 } 723 724 add_wait_queue(&proc->wait, &wait); 725 726 repeat: 727 set_current_state(TASK_INTERRUPTIBLE); 728 if (list_empty(&proc->asts) && !signal_pending(current)) { 729 spin_unlock(&proc->asts_spin); 730 schedule(); 731 spin_lock(&proc->asts_spin); 732 goto repeat; 733 } 734 set_current_state(TASK_RUNNING); 735 remove_wait_queue(&proc->wait, &wait); 736 737 if (signal_pending(current)) { 738 spin_unlock(&proc->asts_spin); 739 return -ERESTARTSYS; 740 } 741 } 742 743 if (list_empty(&proc->asts)) { 744 spin_unlock(&proc->asts_spin); 745 return -EAGAIN; 746 } 747 748 /* there may be both completion and blocking asts to return for 749 the lkb, don't remove lkb from asts list unless no asts remain */ 750 751 lkb = list_entry(proc->asts.next, struct dlm_lkb, lkb_astqueue); 752 753 if (lkb->lkb_ast_type & AST_COMP) { 754 lkb->lkb_ast_type &= ~AST_COMP; 755 type = AST_COMP; 756 } else if (lkb->lkb_ast_type & AST_BAST) { 757 lkb->lkb_ast_type &= ~AST_BAST; 758 type = AST_BAST; 759 bmode = lkb->lkb_bastmode; 760 } 761 762 if (!lkb->lkb_ast_type) { 763 list_del(&lkb->lkb_astqueue); 764 removed = 1; 765 } 766 spin_unlock(&proc->asts_spin); 767 768 ua = (struct dlm_user_args *)lkb->lkb_astparam; 769 error = copy_result_to_user(ua, 770 test_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags), 771 type, bmode, buf, count); 772 773 /* removes reference for the proc->asts lists added by 774 dlm_user_add_ast() and may result in the lkb being freed */ 775 if (removed) 776 dlm_put_lkb(lkb); 777 778 return error; 779} 780 781static unsigned int device_poll(struct file *file, poll_table *wait) 782{ 783 struct dlm_user_proc *proc = file->private_data; 784 785 poll_wait(file, &proc->wait, wait); 786 787 spin_lock(&proc->asts_spin); 788 if (!list_empty(&proc->asts)) { 789 spin_unlock(&proc->asts_spin); 790 return POLLIN | POLLRDNORM; 791 } 792 spin_unlock(&proc->asts_spin); 793 return 0; 794} 795 796static int ctl_device_open(struct inode *inode, struct file *file) 797{ 798 file->private_data = NULL; 799 return 0; 800} 801 802static int ctl_device_close(struct inode *inode, struct file *file) 803{ 804 return 0; 805} 806 807static const struct file_operations device_fops = { 808 .open = device_open, 809 .release = device_close, 810 .read = device_read, 811 .write = device_write, 812 .poll = device_poll, 813 .owner = THIS_MODULE, 814}; 815 816static const struct file_operations ctl_device_fops = { 817 .open = ctl_device_open, 818 .release = ctl_device_close, 819 .write = device_write, 820 .owner = THIS_MODULE, 821}; 822 823int dlm_user_init(void) 824{ 825 int error; 826 827 ctl_device.name = "dlm-control"; 828 ctl_device.fops = &ctl_device_fops; 829 ctl_device.minor = MISC_DYNAMIC_MINOR; 830 831 error = misc_register(&ctl_device); 832 if (error) 833 log_print("misc_register failed for control device"); 834 835 return error; 836} 837 838void dlm_user_exit(void) 839{ 840 misc_deregister(&ctl_device); 841} 842