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1.1 ! nbrk 1: /* $OpenBSD: vfs_lockf.c,v 1.12 2005/11/20 21:55:15 pedro Exp $ */
! 2: /* $NetBSD: vfs_lockf.c,v 1.7 1996/02/04 02:18:21 christos Exp $ */
! 3:
! 4: /*
! 5: * Copyright (c) 1982, 1986, 1989, 1993
! 6: * The Regents of the University of California. All rights reserved.
! 7: *
! 8: * This code is derived from software contributed to Berkeley by
! 9: * Scooter Morris at Genentech Inc.
! 10: *
! 11: * Redistribution and use in source and binary forms, with or without
! 12: * modification, are permitted provided that the following conditions
! 13: * are met:
! 14: * 1. Redistributions of source code must retain the above copyright
! 15: * notice, this list of conditions and the following disclaimer.
! 16: * 2. Redistributions in binary form must reproduce the above copyright
! 17: * notice, this list of conditions and the following disclaimer in the
! 18: * documentation and/or other materials provided with the distribution.
! 19: * 3. Neither the name of the University nor the names of its contributors
! 20: * may be used to endorse or promote products derived from this software
! 21: * without specific prior written permission.
! 22: *
! 23: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
! 24: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
! 25: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
! 26: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
! 27: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
! 28: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
! 29: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
! 30: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
! 31: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
! 32: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
! 33: * SUCH DAMAGE.
! 34: *
! 35: * @(#)ufs_lockf.c 8.3 (Berkeley) 1/6/94
! 36: */
! 37:
! 38: #include <sys/param.h>
! 39: #include <sys/systm.h>
! 40: #include <sys/kernel.h>
! 41: #include <sys/file.h>
! 42: #include <sys/proc.h>
! 43: #include <sys/vnode.h>
! 44: #include <sys/pool.h>
! 45: #include <sys/fcntl.h>
! 46: #include <sys/lockf.h>
! 47:
! 48: struct pool lockfpool;
! 49:
! 50: /*
! 51: * This variable controls the maximum number of processes that will
! 52: * be checked in doing deadlock detection.
! 53: */
! 54: int maxlockdepth = MAXDEPTH;
! 55:
! 56: #define SELF 0x1
! 57: #define OTHERS 0x2
! 58:
! 59: #ifdef LOCKF_DEBUG
! 60:
! 61: #define DEBUG_SETLOCK 0x01
! 62: #define DEBUG_CLEARLOCK 0x02
! 63: #define DEBUG_GETLOCK 0x04
! 64: #define DEBUG_FINDOVR 0x08
! 65: #define DEBUG_SPLIT 0x10
! 66: #define DEBUG_WAKELOCK 0x20
! 67:
! 68: int lockf_debug = DEBUG_SETLOCK|DEBUG_CLEARLOCK|DEBUG_WAKELOCK;
! 69:
! 70: #define DPRINTF(args, level) if (lockf_debug & (level)) printf args
! 71: #else
! 72: #define DPRINTF(args, level)
! 73: #endif
! 74:
! 75: void
! 76: lf_init(void)
! 77: {
! 78: pool_init(&lockfpool, sizeof(struct lockf), 0, 0, 0,
! 79: "lockfpl", &pool_allocator_nointr);
! 80: }
! 81:
! 82: struct lockf *lf_alloc(uid_t, int);
! 83: void lf_free(struct lockf *);
! 84:
! 85: /*
! 86: * We enforce a limit on locks by uid, so that a single user cannot
! 87: * run the kernel out of memory. For now, the limit is pretty coarse.
! 88: * There is no limit on root.
! 89: *
! 90: * Splitting a lock will always succeed, regardless of current allocations.
! 91: * If you're slightly above the limit, we still have to permit an allocation
! 92: * so that the unlock can succeed. If the unlocking causes too many splits,
! 93: * however, you're totally cutoff.
! 94: */
! 95: int maxlocksperuid = 1024;
! 96:
! 97: /*
! 98: * 3 options for allowfail.
! 99: * 0 - always allocate. 1 - cutoff at limit. 2 - cutoff at double limit.
! 100: */
! 101: struct lockf *
! 102: lf_alloc(uid_t uid, int allowfail)
! 103: {
! 104: struct uidinfo *uip;
! 105: struct lockf *lock;
! 106:
! 107: uip = uid_find(uid);
! 108: if (uid && allowfail && uip->ui_lockcnt >
! 109: (allowfail == 1 ? maxlocksperuid : (maxlocksperuid * 2)))
! 110: return (NULL);
! 111: uip->ui_lockcnt++;
! 112: lock = pool_get(&lockfpool, PR_WAITOK);
! 113: lock->lf_uid = uid;
! 114: return (lock);
! 115: }
! 116:
! 117: void
! 118: lf_free(struct lockf *lock)
! 119: {
! 120: struct uidinfo *uip;
! 121:
! 122: uip = uid_find(lock->lf_uid);
! 123: uip->ui_lockcnt--;
! 124: pool_put(&lockfpool, lock);
! 125: }
! 126:
! 127:
! 128: /*
! 129: * Do an advisory lock operation.
! 130: */
! 131: int
! 132: lf_advlock(struct lockf **head, off_t size, caddr_t id, int op,
! 133: struct flock *fl, int flags)
! 134: {
! 135: struct proc *p = curproc;
! 136: struct lockf *lock;
! 137: off_t start, end;
! 138: int error;
! 139:
! 140: /*
! 141: * Convert the flock structure into a start and end.
! 142: */
! 143: switch (fl->l_whence) {
! 144:
! 145: case SEEK_SET:
! 146: case SEEK_CUR:
! 147: /*
! 148: * Caller is responsible for adding any necessary offset
! 149: * when SEEK_CUR is used.
! 150: */
! 151: start = fl->l_start;
! 152: break;
! 153:
! 154: case SEEK_END:
! 155: start = size + fl->l_start;
! 156: break;
! 157:
! 158: default:
! 159: return (EINVAL);
! 160: }
! 161: if (start < 0)
! 162: return (EINVAL);
! 163: if (fl->l_len == 0)
! 164: end = -1;
! 165: else {
! 166: end = start + fl->l_len - 1;
! 167: if (end < start)
! 168: return (EINVAL);
! 169: }
! 170:
! 171: /*
! 172: * Avoid the common case of unlocking when inode has no locks.
! 173: */
! 174: if (*head == NULL) {
! 175: if (op != F_SETLK) {
! 176: fl->l_type = F_UNLCK;
! 177: return (0);
! 178: }
! 179: }
! 180:
! 181: /*
! 182: * Create the lockf structure.
! 183: */
! 184: lock = lf_alloc(p->p_ucred->cr_uid, op != F_UNLCK ? 1 : 2);
! 185: if (!lock)
! 186: return (ENOMEM);
! 187: lock->lf_start = start;
! 188: lock->lf_end = end;
! 189: lock->lf_id = id;
! 190: lock->lf_head = head;
! 191: lock->lf_type = fl->l_type;
! 192: lock->lf_next = NULL;
! 193: TAILQ_INIT(&lock->lf_blkhd);
! 194: lock->lf_flags = flags;
! 195: /*
! 196: * Do the requested operation.
! 197: */
! 198: switch (op) {
! 199:
! 200: case F_SETLK:
! 201: return (lf_setlock(lock));
! 202:
! 203: case F_UNLCK:
! 204: error = lf_clearlock(lock);
! 205: lf_free(lock);
! 206: return (error);
! 207:
! 208: case F_GETLK:
! 209: error = lf_getlock(lock, fl);
! 210: lf_free(lock);
! 211: return (error);
! 212:
! 213: default:
! 214: lf_free(lock);
! 215: return (EINVAL);
! 216: }
! 217: /* NOTREACHED */
! 218: }
! 219:
! 220: /*
! 221: * Set a byte-range lock.
! 222: */
! 223: int
! 224: lf_setlock(struct lockf *lock)
! 225: {
! 226: struct lockf *block;
! 227: struct lockf **head = lock->lf_head;
! 228: struct lockf **prev, *overlap, *ltmp;
! 229: static char lockstr[] = "lockf";
! 230: int ovcase, priority, needtolink, error;
! 231:
! 232: #ifdef LOCKF_DEBUG
! 233: if (lockf_debug & DEBUG_SETLOCK)
! 234: lf_print("lf_setlock", lock);
! 235: #endif /* LOCKF_DEBUG */
! 236:
! 237: /*
! 238: * Set the priority
! 239: */
! 240: priority = PLOCK;
! 241: if (lock->lf_type == F_WRLCK)
! 242: priority += 4;
! 243: priority |= PCATCH;
! 244: /*
! 245: * Scan lock list for this file looking for locks that would block us.
! 246: */
! 247: while ((block = lf_getblock(lock)) != NULL) {
! 248: /*
! 249: * Free the structure and return if nonblocking.
! 250: */
! 251: if ((lock->lf_flags & F_WAIT) == 0) {
! 252: lf_free(lock);
! 253: return (EAGAIN);
! 254: }
! 255: /*
! 256: * We are blocked. Since flock style locks cover
! 257: * the whole file, there is no chance for deadlock.
! 258: * For byte-range locks we must check for deadlock.
! 259: *
! 260: * Deadlock detection is done by looking through the
! 261: * wait channels to see if there are any cycles that
! 262: * involve us. MAXDEPTH is set just to make sure we
! 263: * do not go off into neverland.
! 264: */
! 265: if ((lock->lf_flags & F_POSIX) &&
! 266: (block->lf_flags & F_POSIX)) {
! 267: struct proc *wproc;
! 268: struct lockf *waitblock;
! 269: int i = 0;
! 270:
! 271: /* The block is waiting on something */
! 272: wproc = (struct proc *)block->lf_id;
! 273: while (wproc->p_wchan &&
! 274: (wproc->p_wmesg == lockstr) &&
! 275: (i++ < maxlockdepth)) {
! 276: waitblock = (struct lockf *)wproc->p_wchan;
! 277: /* Get the owner of the blocking lock */
! 278: waitblock = waitblock->lf_next;
! 279: if ((waitblock->lf_flags & F_POSIX) == 0)
! 280: break;
! 281: wproc = (struct proc *)waitblock->lf_id;
! 282: if (wproc == (struct proc *)lock->lf_id) {
! 283: lf_free(lock);
! 284: return (EDEADLK);
! 285: }
! 286: }
! 287: }
! 288: /*
! 289: * For flock type locks, we must first remove
! 290: * any shared locks that we hold before we sleep
! 291: * waiting for an exclusive lock.
! 292: */
! 293: if ((lock->lf_flags & F_FLOCK) &&
! 294: lock->lf_type == F_WRLCK) {
! 295: lock->lf_type = F_UNLCK;
! 296: (void) lf_clearlock(lock);
! 297: lock->lf_type = F_WRLCK;
! 298: }
! 299: /*
! 300: * Add our lock to the blocked list and sleep until we're free.
! 301: * Remember who blocked us (for deadlock detection).
! 302: */
! 303: lock->lf_next = block;
! 304: #ifdef LOCKF_DEBUG
! 305: if (lockf_debug & DEBUG_SETLOCK) {
! 306: lf_print("lf_setlock", lock);
! 307: lf_print("lf_setlock: blocking on", block);
! 308: }
! 309: #endif /* LOCKF_DEBUG */
! 310: TAILQ_INSERT_TAIL(&block->lf_blkhd, lock, lf_block);
! 311: error = tsleep(lock, priority, lockstr, 0);
! 312: #if 0
! 313: if (error) {
! 314: /*
! 315: * Delete ourselves from the waiting to lock list.
! 316: */
! 317: TAILQ_REMOVE(&lock->lf_next->lf_blkhd, lock, lf_block);
! 318: lf_free(lock);
! 319: return (error);
! 320: }
! 321: #else
! 322: if (lock->lf_next != NULL) {
! 323: TAILQ_REMOVE(&lock->lf_next->lf_blkhd, lock, lf_block);
! 324: lock->lf_next = NULL;
! 325: }
! 326: if (error) {
! 327: lf_free(lock);
! 328: return (error);
! 329: }
! 330: #endif
! 331: }
! 332: /*
! 333: * No blocks!! Add the lock. Note that we will
! 334: * downgrade or upgrade any overlapping locks this
! 335: * process already owns.
! 336: *
! 337: * Skip over locks owned by other processes.
! 338: * Handle any locks that overlap and are owned by ourselves.
! 339: */
! 340: prev = head;
! 341: block = *head;
! 342: needtolink = 1;
! 343: for (;;) {
! 344: ovcase = lf_findoverlap(block, lock, SELF, &prev, &overlap);
! 345: if (ovcase)
! 346: block = overlap->lf_next;
! 347: /*
! 348: * Six cases:
! 349: * 0) no overlap
! 350: * 1) overlap == lock
! 351: * 2) overlap contains lock
! 352: * 3) lock contains overlap
! 353: * 4) overlap starts before lock
! 354: * 5) overlap ends after lock
! 355: */
! 356: switch (ovcase) {
! 357: case 0: /* no overlap */
! 358: if (needtolink) {
! 359: *prev = lock;
! 360: lock->lf_next = overlap;
! 361: }
! 362: break;
! 363:
! 364: case 1: /* overlap == lock */
! 365: /*
! 366: * If downgrading lock, others may be
! 367: * able to acquire it.
! 368: */
! 369: if (lock->lf_type == F_RDLCK &&
! 370: overlap->lf_type == F_WRLCK)
! 371: lf_wakelock(overlap);
! 372: overlap->lf_type = lock->lf_type;
! 373: lf_free(lock);
! 374: lock = overlap; /* for debug output below */
! 375: break;
! 376:
! 377: case 2: /* overlap contains lock */
! 378: /*
! 379: * Check for common starting point and different types.
! 380: */
! 381: if (overlap->lf_type == lock->lf_type) {
! 382: lf_free(lock);
! 383: lock = overlap; /* for debug output below */
! 384: break;
! 385: }
! 386: if (overlap->lf_start == lock->lf_start) {
! 387: *prev = lock;
! 388: lock->lf_next = overlap;
! 389: overlap->lf_start = lock->lf_end + 1;
! 390: } else
! 391: lf_split(overlap, lock);
! 392: lf_wakelock(overlap);
! 393: break;
! 394:
! 395: case 3: /* lock contains overlap */
! 396: /*
! 397: * If downgrading lock, others may be able to
! 398: * acquire it, otherwise take the list.
! 399: */
! 400: if (lock->lf_type == F_RDLCK &&
! 401: overlap->lf_type == F_WRLCK) {
! 402: lf_wakelock(overlap);
! 403: } else {
! 404: while ((ltmp =
! 405: TAILQ_FIRST(&overlap->lf_blkhd))) {
! 406: TAILQ_REMOVE(&overlap->lf_blkhd, ltmp,
! 407: lf_block);
! 408: ltmp->lf_next = lock;
! 409: TAILQ_INSERT_TAIL(&lock->lf_blkhd,
! 410: ltmp, lf_block);
! 411: }
! 412: }
! 413: /*
! 414: * Add the new lock if necessary and delete the overlap.
! 415: */
! 416: if (needtolink) {
! 417: *prev = lock;
! 418: lock->lf_next = overlap->lf_next;
! 419: prev = &lock->lf_next;
! 420: needtolink = 0;
! 421: } else
! 422: *prev = overlap->lf_next;
! 423: lf_free(overlap);
! 424: continue;
! 425:
! 426: case 4: /* overlap starts before lock */
! 427: /*
! 428: * Add lock after overlap on the list.
! 429: */
! 430: lock->lf_next = overlap->lf_next;
! 431: overlap->lf_next = lock;
! 432: overlap->lf_end = lock->lf_start - 1;
! 433: prev = &lock->lf_next;
! 434: lf_wakelock(overlap);
! 435: needtolink = 0;
! 436: continue;
! 437:
! 438: case 5: /* overlap ends after lock */
! 439: /*
! 440: * Add the new lock before overlap.
! 441: */
! 442: if (needtolink) {
! 443: *prev = lock;
! 444: lock->lf_next = overlap;
! 445: }
! 446: overlap->lf_start = lock->lf_end + 1;
! 447: lf_wakelock(overlap);
! 448: break;
! 449: }
! 450: break;
! 451: }
! 452: #ifdef LOCKF_DEBUG
! 453: if (lockf_debug & DEBUG_SETLOCK) {
! 454: lf_print("lf_setlock: got the lock", lock);
! 455: }
! 456: #endif /* LOCKF_DEBUG */
! 457: return (0);
! 458: }
! 459:
! 460: /*
! 461: * Remove a byte-range lock on an inode.
! 462: *
! 463: * Generally, find the lock (or an overlap to that lock)
! 464: * and remove it (or shrink it), then wakeup anyone we can.
! 465: */
! 466: int
! 467: lf_clearlock(struct lockf *lock)
! 468: {
! 469: struct lockf **head = lock->lf_head;
! 470: struct lockf *lf = *head;
! 471: struct lockf *overlap, **prev;
! 472: int ovcase;
! 473:
! 474: if (lf == NULL)
! 475: return (0);
! 476: #ifdef LOCKF_DEBUG
! 477: if (lockf_debug & DEBUG_CLEARLOCK)
! 478: lf_print("lf_clearlock", lock);
! 479: #endif /* LOCKF_DEBUG */
! 480: prev = head;
! 481: while ((ovcase = lf_findoverlap(lf, lock, SELF,
! 482: &prev, &overlap)) != 0) {
! 483: /*
! 484: * Wakeup the list of locks to be retried.
! 485: */
! 486: lf_wakelock(overlap);
! 487:
! 488: switch (ovcase) {
! 489:
! 490: case 1: /* overlap == lock */
! 491: *prev = overlap->lf_next;
! 492: lf_free(overlap);
! 493: break;
! 494:
! 495: case 2: /* overlap contains lock: split it */
! 496: if (overlap->lf_start == lock->lf_start) {
! 497: overlap->lf_start = lock->lf_end + 1;
! 498: break;
! 499: }
! 500: lf_split(overlap, lock);
! 501: overlap->lf_next = lock->lf_next;
! 502: break;
! 503:
! 504: case 3: /* lock contains overlap */
! 505: *prev = overlap->lf_next;
! 506: lf = overlap->lf_next;
! 507: lf_free(overlap);
! 508: continue;
! 509:
! 510: case 4: /* overlap starts before lock */
! 511: overlap->lf_end = lock->lf_start - 1;
! 512: prev = &overlap->lf_next;
! 513: lf = overlap->lf_next;
! 514: continue;
! 515:
! 516: case 5: /* overlap ends after lock */
! 517: overlap->lf_start = lock->lf_end + 1;
! 518: break;
! 519: }
! 520: break;
! 521: }
! 522: return (0);
! 523: }
! 524:
! 525: /*
! 526: * Check whether there is a blocking lock,
! 527: * and if so return its process identifier.
! 528: */
! 529: int
! 530: lf_getlock(struct lockf *lock, struct flock *fl)
! 531: {
! 532: struct lockf *block;
! 533:
! 534: #ifdef LOCKF_DEBUG
! 535: if (lockf_debug & DEBUG_CLEARLOCK)
! 536: lf_print("lf_getlock", lock);
! 537: #endif /* LOCKF_DEBUG */
! 538:
! 539: if ((block = lf_getblock(lock)) != NULL) {
! 540: fl->l_type = block->lf_type;
! 541: fl->l_whence = SEEK_SET;
! 542: fl->l_start = block->lf_start;
! 543: if (block->lf_end == -1)
! 544: fl->l_len = 0;
! 545: else
! 546: fl->l_len = block->lf_end - block->lf_start + 1;
! 547: if (block->lf_flags & F_POSIX)
! 548: fl->l_pid = ((struct proc *)(block->lf_id))->p_pid;
! 549: else
! 550: fl->l_pid = -1;
! 551: } else {
! 552: fl->l_type = F_UNLCK;
! 553: }
! 554: return (0);
! 555: }
! 556:
! 557: /*
! 558: * Walk the list of locks for an inode and
! 559: * return the first blocking lock.
! 560: */
! 561: struct lockf *
! 562: lf_getblock(struct lockf *lock)
! 563: {
! 564: struct lockf **prev, *overlap, *lf;
! 565:
! 566: prev = lock->lf_head;
! 567: lf = *prev;
! 568: while (lf_findoverlap(lf, lock, OTHERS, &prev, &overlap) != 0) {
! 569: /*
! 570: * We've found an overlap, see if it blocks us
! 571: */
! 572: if ((lock->lf_type == F_WRLCK || overlap->lf_type == F_WRLCK))
! 573: return (overlap);
! 574: /*
! 575: * Nope, point to the next one on the list and
! 576: * see if it blocks us
! 577: */
! 578: lf = overlap->lf_next;
! 579: }
! 580: return (NULL);
! 581: }
! 582:
! 583: /*
! 584: * Walk the list of locks for an inode to
! 585: * find an overlapping lock (if any).
! 586: *
! 587: * NOTE: this returns only the FIRST overlapping lock. There
! 588: * may be more than one.
! 589: */
! 590: int
! 591: lf_findoverlap(struct lockf *lf, struct lockf *lock, int type,
! 592: struct lockf ***prev, struct lockf **overlap)
! 593: {
! 594: off_t start, end;
! 595:
! 596: #ifdef LOCKF_DEBUG
! 597: if (lf && lockf_debug & DEBUG_FINDOVR)
! 598: lf_print("lf_findoverlap: looking for overlap in", lock);
! 599: #endif /* LOCKF_DEBUG */
! 600:
! 601: *overlap = lf;
! 602: start = lock->lf_start;
! 603: end = lock->lf_end;
! 604: while (lf != NULL) {
! 605: if (((type & SELF) && lf->lf_id != lock->lf_id) ||
! 606: ((type & OTHERS) && lf->lf_id == lock->lf_id)) {
! 607: *prev = &lf->lf_next;
! 608: *overlap = lf = lf->lf_next;
! 609: continue;
! 610: }
! 611: #ifdef LOCKF_DEBUG
! 612: if (lockf_debug & DEBUG_FINDOVR)
! 613: lf_print("\tchecking", lf);
! 614: #endif /* LOCKF_DEBUG */
! 615: /*
! 616: * OK, check for overlap
! 617: *
! 618: * Six cases:
! 619: * 0) no overlap
! 620: * 1) overlap == lock
! 621: * 2) overlap contains lock
! 622: * 3) lock contains overlap
! 623: * 4) overlap starts before lock
! 624: * 5) overlap ends after lock
! 625: */
! 626:
! 627: /* Case 0 */
! 628: if ((lf->lf_end != -1 && start > lf->lf_end) ||
! 629: (end != -1 && lf->lf_start > end)) {
! 630: DPRINTF(("no overlap\n"), DEBUG_FINDOVR);
! 631: if ((type & SELF) && end != -1 && lf->lf_start > end)
! 632: return (0);
! 633: *prev = &lf->lf_next;
! 634: *overlap = lf = lf->lf_next;
! 635: continue;
! 636: }
! 637: /* Case 1 */
! 638: if ((lf->lf_start == start) && (lf->lf_end == end)) {
! 639: DPRINTF(("overlap == lock\n"), DEBUG_FINDOVR);
! 640: return (1);
! 641: }
! 642: /* Case 2 */
! 643: if ((lf->lf_start <= start) &&
! 644: (lf->lf_end == -1 ||
! 645: (end != -1 && lf->lf_end >= end))) {
! 646: DPRINTF(("overlap contains lock\n"), DEBUG_FINDOVR);
! 647: return (2);
! 648: }
! 649: /* Case 3 */
! 650: if (start <= lf->lf_start &&
! 651: (end == -1 ||
! 652: (lf->lf_end != -1 && end >= lf->lf_end))) {
! 653: DPRINTF(("lock contains overlap\n"), DEBUG_FINDOVR);
! 654: return (3);
! 655: }
! 656: /* Case 4 */
! 657: if ((lf->lf_start < start) &&
! 658: ((lf->lf_end >= start) || (lf->lf_end == -1))) {
! 659: DPRINTF(("overlap starts before lock\n"),
! 660: DEBUG_FINDOVR);
! 661: return (4);
! 662: }
! 663: /* Case 5 */
! 664: if ((lf->lf_start > start) &&
! 665: (end != -1) &&
! 666: ((lf->lf_end > end) || (lf->lf_end == -1))) {
! 667: DPRINTF(("overlap ends after lock\n"), DEBUG_FINDOVR);
! 668: return (5);
! 669: }
! 670: panic("lf_findoverlap: default");
! 671: }
! 672: return (0);
! 673: }
! 674:
! 675: /*
! 676: * Split a lock and a contained region into
! 677: * two or three locks as necessary.
! 678: */
! 679: void
! 680: lf_split(struct lockf *lock1, struct lockf *lock2)
! 681: {
! 682: struct lockf *splitlock;
! 683:
! 684: #ifdef LOCKF_DEBUG
! 685: if (lockf_debug & DEBUG_SPLIT) {
! 686: lf_print("lf_split", lock1);
! 687: lf_print("splitting from", lock2);
! 688: }
! 689: #endif /* LOCKF_DEBUG */
! 690: /*
! 691: * Check to see if spliting into only two pieces.
! 692: */
! 693: if (lock1->lf_start == lock2->lf_start) {
! 694: lock1->lf_start = lock2->lf_end + 1;
! 695: lock2->lf_next = lock1;
! 696: return;
! 697: }
! 698: if (lock1->lf_end == lock2->lf_end) {
! 699: lock1->lf_end = lock2->lf_start - 1;
! 700: lock2->lf_next = lock1->lf_next;
! 701: lock1->lf_next = lock2;
! 702: return;
! 703: }
! 704: /*
! 705: * Make a new lock consisting of the last part of
! 706: * the encompassing lock
! 707: */
! 708: splitlock = lf_alloc(lock1->lf_uid, 0);
! 709: memcpy(splitlock, lock1, sizeof(*splitlock));
! 710: splitlock->lf_start = lock2->lf_end + 1;
! 711: splitlock->lf_block.tqe_next = NULL;
! 712: TAILQ_INIT(&splitlock->lf_blkhd);
! 713: lock1->lf_end = lock2->lf_start - 1;
! 714: /*
! 715: * OK, now link it in
! 716: */
! 717: lock2->lf_next = splitlock;
! 718: lock1->lf_next = lock2;
! 719: }
! 720:
! 721: /*
! 722: * Wakeup a blocklist
! 723: */
! 724: void
! 725: lf_wakelock(struct lockf *lock)
! 726: {
! 727: struct lockf *wakelock;
! 728:
! 729: while ((wakelock = TAILQ_FIRST(&lock->lf_blkhd))) {
! 730: TAILQ_REMOVE(&lock->lf_blkhd, wakelock, lf_block);
! 731: wakelock->lf_next = NULL;
! 732: wakeup_one(wakelock);
! 733: }
! 734: }
! 735:
! 736: #ifdef LOCKF_DEBUG
! 737: /*
! 738: * Print out a lock.
! 739: */
! 740: void
! 741: lf_print(char *tag, struct lockf *lock)
! 742: {
! 743: struct lockf *block;
! 744:
! 745: printf("%s: lock %p for ", tag, lock);
! 746: if (lock->lf_flags & F_POSIX)
! 747: printf("proc %d", ((struct proc *)(lock->lf_id))->p_pid);
! 748: else
! 749: printf("id %p", lock->lf_id);
! 750: printf(" %s, start %llx, end %llx",
! 751: lock->lf_type == F_RDLCK ? "shared" :
! 752: lock->lf_type == F_WRLCK ? "exclusive" :
! 753: lock->lf_type == F_UNLCK ? "unlock" :
! 754: "unknown", lock->lf_start, lock->lf_end);
! 755: block = TAILQ_FIRST(&lock->lf_blkhd);
! 756: if (block)
! 757: printf(" block");
! 758: TAILQ_FOREACH(block, &lock->lf_blkhd, lf_block)
! 759: printf(" %p,", block);
! 760: printf("\n");
! 761:
! 762: }
! 763:
! 764: void
! 765: lf_printlist(char *tag, struct lockf *lock)
! 766: {
! 767: struct lockf *lf;
! 768:
! 769: printf("%s: Lock list:\n", tag);
! 770: for (lf = *lock->lf_head; lf; lf = lf->lf_next) {
! 771: printf("\tlock %p for ", lf);
! 772: if (lf->lf_flags & F_POSIX)
! 773: printf("proc %d", ((struct proc*)(lf->lf_id))->p_pid);
! 774: else
! 775: printf("id %p", lf->lf_id);
! 776: printf(" %s, start %llx, end %llx",
! 777: lf->lf_type == F_RDLCK ? "shared" :
! 778: lf->lf_type == F_WRLCK ? "exclusive" :
! 779: lf->lf_type == F_UNLCK ? "unlock" :
! 780: "unknown", lf->lf_start, lf->lf_end);
! 781: printf("\n");
! 782: }
! 783: }
! 784: #endif /* LOCKF_DEBUG */