| 1 | /* |
| 2 | * Copyright (c) 1982, 1986, 1989, 1993 |
| 3 | * The Regents of the University of California. All rights reserved. |
| 4 | * |
| 5 | * This code is derived from software contributed to Berkeley by |
| 6 | * Scooter Morris at Genentech Inc. |
| 7 | * |
| 8 | * Redistribution and use in source and binary forms, with or without |
| 9 | * modification, are permitted provided that the following conditions |
| 10 | * are met: |
| 11 | * 1. Redistributions of source code must retain the above copyright |
| 12 | * notice, this list of conditions and the following disclaimer. |
| 13 | * 2. Redistributions in binary form must reproduce the above copyright |
| 14 | * notice, this list of conditions and the following disclaimer in the |
| 15 | * documentation and/or other materials provided with the distribution. |
| 16 | * 3. All advertising materials mentioning features or use of this software |
| 17 | * must display the following acknowledgement: |
| 18 | * This product includes software developed by the University of |
| 19 | * California, Berkeley and its contributors. |
| 20 | * 4. Neither the name of the University nor the names of its contributors |
| 21 | * may be used to endorse or promote products derived from this software |
| 22 | * without specific prior written permission. |
| 23 | * |
| 24 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
| 25 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| 26 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| 27 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
| 28 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| 29 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| 30 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 31 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| 32 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| 33 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| 34 | * SUCH DAMAGE. |
| 35 | * |
| 36 | * @(#)ufs_lockf.c 8.3 (Berkeley) 1/6/94 |
| 37 | * $FreeBSD: src/sys/kern/kern_lockf.c,v 1.25 1999/11/16 16:28:56 phk Exp $ |
| 38 | * $DragonFly: src/sys/kern/kern_lockf.c,v 1.6 2003/08/26 21:09:02 rob Exp $ |
| 39 | */ |
| 40 | |
| 41 | #include "opt_debug_lockf.h" |
| 42 | |
| 43 | #include <sys/param.h> |
| 44 | #include <sys/systm.h> |
| 45 | #include <sys/kernel.h> |
| 46 | #include <sys/lock.h> |
| 47 | #include <sys/proc.h> |
| 48 | #include <sys/unistd.h> |
| 49 | #include <sys/vnode.h> |
| 50 | #include <sys/malloc.h> |
| 51 | #include <sys/fcntl.h> |
| 52 | |
| 53 | #include <sys/lockf.h> |
| 54 | |
| 55 | /* |
| 56 | * This variable controls the maximum number of processes that will |
| 57 | * be checked in doing deadlock detection. |
| 58 | */ |
| 59 | static int maxlockdepth = MAXDEPTH; |
| 60 | |
| 61 | #ifdef LOCKF_DEBUG |
| 62 | #include <sys/kernel.h> |
| 63 | #include <sys/sysctl.h> |
| 64 | |
| 65 | #include <vfs/ufs/quota.h> |
| 66 | #include <vfs/ufs/inode.h> |
| 67 | |
| 68 | |
| 69 | static int lockf_debug = 0; |
| 70 | SYSCTL_INT(_debug, OID_AUTO, lockf_debug, CTLFLAG_RW, &lockf_debug, 0, ""); |
| 71 | #endif |
| 72 | |
| 73 | static MALLOC_DEFINE(M_LOCKF, "lockf", "Byte-range locking structures"); |
| 74 | |
| 75 | #define NOLOCKF (struct lockf *)0 |
| 76 | #define SELF 0x1 |
| 77 | #define OTHERS 0x2 |
| 78 | static int lf_clearlock (struct lockf *); |
| 79 | static int lf_findoverlap (struct lockf *, |
| 80 | struct lockf *, int, struct lockf ***, struct lockf **); |
| 81 | static struct lockf * |
| 82 | lf_getblock (struct lockf *); |
| 83 | static int lf_getlock (struct lockf *, struct flock *); |
| 84 | static int lf_setlock (struct lockf *); |
| 85 | static void lf_split (struct lockf *, struct lockf *); |
| 86 | static void lf_wakelock (struct lockf *); |
| 87 | |
| 88 | /* |
| 89 | * Advisory record locking support |
| 90 | */ |
| 91 | int |
| 92 | lf_advlock(ap, head, size) |
| 93 | struct vop_advlock_args /* { |
| 94 | struct vnode *a_vp; |
| 95 | caddr_t a_id; |
| 96 | int a_op; |
| 97 | struct flock *a_fl; |
| 98 | int a_flags; |
| 99 | } */ *ap; |
| 100 | struct lockf **head; |
| 101 | u_quad_t size; |
| 102 | { |
| 103 | struct flock *fl = ap->a_fl; |
| 104 | struct lockf *lock; |
| 105 | off_t start, end; |
| 106 | int error; |
| 107 | |
| 108 | /* |
| 109 | * Convert the flock structure into a start and end. |
| 110 | */ |
| 111 | switch (fl->l_whence) { |
| 112 | |
| 113 | case SEEK_SET: |
| 114 | case SEEK_CUR: |
| 115 | /* |
| 116 | * Caller is responsible for adding any necessary offset |
| 117 | * when SEEK_CUR is used. |
| 118 | */ |
| 119 | start = fl->l_start; |
| 120 | break; |
| 121 | |
| 122 | case SEEK_END: |
| 123 | start = size + fl->l_start; |
| 124 | break; |
| 125 | |
| 126 | default: |
| 127 | return (EINVAL); |
| 128 | } |
| 129 | if (start < 0) |
| 130 | return (EINVAL); |
| 131 | if (fl->l_len == 0) |
| 132 | end = -1; |
| 133 | else { |
| 134 | end = start + fl->l_len - 1; |
| 135 | if (end < start) |
| 136 | return (EINVAL); |
| 137 | } |
| 138 | /* |
| 139 | * Avoid the common case of unlocking when inode has no locks. |
| 140 | */ |
| 141 | if (*head == (struct lockf *)0) { |
| 142 | if (ap->a_op != F_SETLK) { |
| 143 | fl->l_type = F_UNLCK; |
| 144 | return (0); |
| 145 | } |
| 146 | } |
| 147 | /* |
| 148 | * Create the lockf structure |
| 149 | */ |
| 150 | MALLOC(lock, struct lockf *, sizeof *lock, M_LOCKF, M_WAITOK); |
| 151 | lock->lf_start = start; |
| 152 | lock->lf_end = end; |
| 153 | lock->lf_id = ap->a_id; |
| 154 | /* lock->lf_inode = ip; */ /* XXX JH */ |
| 155 | lock->lf_type = fl->l_type; |
| 156 | lock->lf_head = head; |
| 157 | lock->lf_next = (struct lockf *)0; |
| 158 | TAILQ_INIT(&lock->lf_blkhd); |
| 159 | lock->lf_flags = ap->a_flags; |
| 160 | /* |
| 161 | * Do the requested operation. |
| 162 | */ |
| 163 | switch(ap->a_op) { |
| 164 | case F_SETLK: |
| 165 | return (lf_setlock(lock)); |
| 166 | |
| 167 | case F_UNLCK: |
| 168 | error = lf_clearlock(lock); |
| 169 | FREE(lock, M_LOCKF); |
| 170 | return (error); |
| 171 | |
| 172 | case F_GETLK: |
| 173 | error = lf_getlock(lock, fl); |
| 174 | FREE(lock, M_LOCKF); |
| 175 | return (error); |
| 176 | |
| 177 | default: |
| 178 | free(lock, M_LOCKF); |
| 179 | return (EINVAL); |
| 180 | } |
| 181 | /* NOTREACHED */ |
| 182 | } |
| 183 | |
| 184 | /* |
| 185 | * Set a byte-range lock. |
| 186 | */ |
| 187 | static int |
| 188 | lf_setlock(lock) |
| 189 | struct lockf *lock; |
| 190 | { |
| 191 | struct lockf *block; |
| 192 | struct lockf **head = lock->lf_head; |
| 193 | struct lockf **prev, *overlap, *ltmp; |
| 194 | static char lockstr[] = "lockf"; |
| 195 | int ovcase, needtolink, error; |
| 196 | |
| 197 | #ifdef LOCKF_DEBUG |
| 198 | if (lockf_debug & 1) |
| 199 | lf_print("lf_setlock", lock); |
| 200 | #endif /* LOCKF_DEBUG */ |
| 201 | |
| 202 | /* |
| 203 | * Scan lock list for this file looking for locks that would block us. |
| 204 | */ |
| 205 | while ((block = lf_getblock(lock))) { |
| 206 | /* |
| 207 | * Free the structure and return if nonblocking. |
| 208 | */ |
| 209 | if ((lock->lf_flags & F_WAIT) == 0) { |
| 210 | FREE(lock, M_LOCKF); |
| 211 | return (EAGAIN); |
| 212 | } |
| 213 | /* |
| 214 | * We are blocked. Since flock style locks cover |
| 215 | * the whole file, there is no chance for deadlock. |
| 216 | * For byte-range locks we must check for deadlock. |
| 217 | * |
| 218 | * Deadlock detection is done by looking through the |
| 219 | * wait channels to see if there are any cycles that |
| 220 | * involve us. MAXDEPTH is set just to make sure we |
| 221 | * do not go off into neverland. |
| 222 | */ |
| 223 | if ((lock->lf_flags & F_POSIX) && |
| 224 | (block->lf_flags & F_POSIX)) { |
| 225 | struct proc *wproc; |
| 226 | struct lockf *waitblock; |
| 227 | int i = 0; |
| 228 | |
| 229 | /* The block is waiting on something */ |
| 230 | wproc = (struct proc *)block->lf_id; |
| 231 | while (wproc->p_wchan && |
| 232 | (wproc->p_wmesg == lockstr) && |
| 233 | (i++ < maxlockdepth)) { |
| 234 | waitblock = (struct lockf *)wproc->p_wchan; |
| 235 | /* Get the owner of the blocking lock */ |
| 236 | waitblock = waitblock->lf_next; |
| 237 | if ((waitblock->lf_flags & F_POSIX) == 0) |
| 238 | break; |
| 239 | wproc = (struct proc *)waitblock->lf_id; |
| 240 | if (wproc == (struct proc *)lock->lf_id) { |
| 241 | free(lock, M_LOCKF); |
| 242 | return (EDEADLK); |
| 243 | } |
| 244 | } |
| 245 | } |
| 246 | /* |
| 247 | * For flock type locks, we must first remove |
| 248 | * any shared locks that we hold before we sleep |
| 249 | * waiting for an exclusive lock. |
| 250 | */ |
| 251 | if ((lock->lf_flags & F_FLOCK) && |
| 252 | lock->lf_type == F_WRLCK) { |
| 253 | lock->lf_type = F_UNLCK; |
| 254 | (void) lf_clearlock(lock); |
| 255 | lock->lf_type = F_WRLCK; |
| 256 | } |
| 257 | /* |
| 258 | * Add our lock to the blocked list and sleep until we're free. |
| 259 | * Remember who blocked us (for deadlock detection). |
| 260 | */ |
| 261 | lock->lf_next = block; |
| 262 | TAILQ_INSERT_TAIL(&block->lf_blkhd, lock, lf_block); |
| 263 | #ifdef LOCKF_DEBUG |
| 264 | if (lockf_debug & 1) { |
| 265 | lf_print("lf_setlock: blocking on", block); |
| 266 | lf_printlist("lf_setlock", block); |
| 267 | } |
| 268 | #endif /* LOCKF_DEBUG */ |
| 269 | error = tsleep((caddr_t)lock, PCATCH, lockstr, 0); |
| 270 | /* |
| 271 | * We may have been awakened by a signal and/or by a |
| 272 | * debugger continuing us (in which cases we must remove |
| 273 | * ourselves from the blocked list) and/or by another |
| 274 | * process releasing a lock (in which case we have |
| 275 | * already been removed from the blocked list and our |
| 276 | * lf_next field set to NOLOCKF). |
| 277 | */ |
| 278 | if (lock->lf_next) { |
| 279 | TAILQ_REMOVE(&lock->lf_next->lf_blkhd, lock, lf_block); |
| 280 | lock->lf_next = NOLOCKF; |
| 281 | } |
| 282 | if (error) { |
| 283 | free(lock, M_LOCKF); |
| 284 | return (error); |
| 285 | } |
| 286 | } |
| 287 | /* |
| 288 | * No blocks!! Add the lock. Note that we will |
| 289 | * downgrade or upgrade any overlapping locks this |
| 290 | * process already owns. |
| 291 | * |
| 292 | * Skip over locks owned by other processes. |
| 293 | * Handle any locks that overlap and are owned by ourselves. |
| 294 | */ |
| 295 | prev = head; |
| 296 | block = *head; |
| 297 | needtolink = 1; |
| 298 | for (;;) { |
| 299 | ovcase = lf_findoverlap(block, lock, SELF, &prev, &overlap); |
| 300 | if (ovcase) |
| 301 | block = overlap->lf_next; |
| 302 | /* |
| 303 | * Six cases: |
| 304 | * 0) no overlap |
| 305 | * 1) overlap == lock |
| 306 | * 2) overlap contains lock |
| 307 | * 3) lock contains overlap |
| 308 | * 4) overlap starts before lock |
| 309 | * 5) overlap ends after lock |
| 310 | */ |
| 311 | switch (ovcase) { |
| 312 | case 0: /* no overlap */ |
| 313 | if (needtolink) { |
| 314 | *prev = lock; |
| 315 | lock->lf_next = overlap; |
| 316 | } |
| 317 | break; |
| 318 | |
| 319 | case 1: /* overlap == lock */ |
| 320 | /* |
| 321 | * If downgrading lock, others may be |
| 322 | * able to acquire it. |
| 323 | */ |
| 324 | if (lock->lf_type == F_RDLCK && |
| 325 | overlap->lf_type == F_WRLCK) |
| 326 | lf_wakelock(overlap); |
| 327 | overlap->lf_type = lock->lf_type; |
| 328 | FREE(lock, M_LOCKF); |
| 329 | lock = overlap; /* for debug output below */ |
| 330 | break; |
| 331 | |
| 332 | case 2: /* overlap contains lock */ |
| 333 | /* |
| 334 | * Check for common starting point and different types. |
| 335 | */ |
| 336 | if (overlap->lf_type == lock->lf_type) { |
| 337 | free(lock, M_LOCKF); |
| 338 | lock = overlap; /* for debug output below */ |
| 339 | break; |
| 340 | } |
| 341 | if (overlap->lf_start == lock->lf_start) { |
| 342 | *prev = lock; |
| 343 | lock->lf_next = overlap; |
| 344 | overlap->lf_start = lock->lf_end + 1; |
| 345 | } else |
| 346 | lf_split(overlap, lock); |
| 347 | lf_wakelock(overlap); |
| 348 | break; |
| 349 | |
| 350 | case 3: /* lock contains overlap */ |
| 351 | /* |
| 352 | * If downgrading lock, others may be able to |
| 353 | * acquire it, otherwise take the list. |
| 354 | */ |
| 355 | if (lock->lf_type == F_RDLCK && |
| 356 | overlap->lf_type == F_WRLCK) { |
| 357 | lf_wakelock(overlap); |
| 358 | } else { |
| 359 | while (!TAILQ_EMPTY(&overlap->lf_blkhd)) { |
| 360 | ltmp = TAILQ_FIRST(&overlap->lf_blkhd); |
| 361 | TAILQ_REMOVE(&overlap->lf_blkhd, ltmp, |
| 362 | lf_block); |
| 363 | TAILQ_INSERT_TAIL(&lock->lf_blkhd, |
| 364 | ltmp, lf_block); |
| 365 | ltmp->lf_next = lock; |
| 366 | } |
| 367 | } |
| 368 | /* |
| 369 | * Add the new lock if necessary and delete the overlap. |
| 370 | */ |
| 371 | if (needtolink) { |
| 372 | *prev = lock; |
| 373 | lock->lf_next = overlap->lf_next; |
| 374 | prev = &lock->lf_next; |
| 375 | needtolink = 0; |
| 376 | } else |
| 377 | *prev = overlap->lf_next; |
| 378 | free(overlap, M_LOCKF); |
| 379 | continue; |
| 380 | |
| 381 | case 4: /* overlap starts before lock */ |
| 382 | /* |
| 383 | * Add lock after overlap on the list. |
| 384 | */ |
| 385 | lock->lf_next = overlap->lf_next; |
| 386 | overlap->lf_next = lock; |
| 387 | overlap->lf_end = lock->lf_start - 1; |
| 388 | prev = &lock->lf_next; |
| 389 | lf_wakelock(overlap); |
| 390 | needtolink = 0; |
| 391 | continue; |
| 392 | |
| 393 | case 5: /* overlap ends after lock */ |
| 394 | /* |
| 395 | * Add the new lock before overlap. |
| 396 | */ |
| 397 | if (needtolink) { |
| 398 | *prev = lock; |
| 399 | lock->lf_next = overlap; |
| 400 | } |
| 401 | overlap->lf_start = lock->lf_end + 1; |
| 402 | lf_wakelock(overlap); |
| 403 | break; |
| 404 | } |
| 405 | break; |
| 406 | } |
| 407 | #ifdef LOCKF_DEBUG |
| 408 | if (lockf_debug & 1) { |
| 409 | lf_print("lf_setlock: got the lock", lock); |
| 410 | lf_printlist("lf_setlock", lock); |
| 411 | } |
| 412 | #endif /* LOCKF_DEBUG */ |
| 413 | return (0); |
| 414 | } |
| 415 | |
| 416 | /* |
| 417 | * Remove a byte-range lock on an inode. |
| 418 | * |
| 419 | * Generally, find the lock (or an overlap to that lock) |
| 420 | * and remove it (or shrink it), then wakeup anyone we can. |
| 421 | */ |
| 422 | static int |
| 423 | lf_clearlock(unlock) |
| 424 | struct lockf *unlock; |
| 425 | { |
| 426 | struct lockf **head = unlock->lf_head; |
| 427 | struct lockf *lf = *head; |
| 428 | struct lockf *overlap, **prev; |
| 429 | int ovcase; |
| 430 | |
| 431 | if (lf == NOLOCKF) |
| 432 | return (0); |
| 433 | #ifdef LOCKF_DEBUG |
| 434 | if (unlock->lf_type != F_UNLCK) |
| 435 | panic("lf_clearlock: bad type"); |
| 436 | if (lockf_debug & 1) |
| 437 | lf_print("lf_clearlock", unlock); |
| 438 | #endif /* LOCKF_DEBUG */ |
| 439 | prev = head; |
| 440 | while ((ovcase = lf_findoverlap(lf, unlock, SELF, &prev, &overlap))) { |
| 441 | /* |
| 442 | * Wakeup the list of locks to be retried. |
| 443 | */ |
| 444 | lf_wakelock(overlap); |
| 445 | |
| 446 | switch (ovcase) { |
| 447 | |
| 448 | case 1: /* overlap == lock */ |
| 449 | *prev = overlap->lf_next; |
| 450 | FREE(overlap, M_LOCKF); |
| 451 | break; |
| 452 | |
| 453 | case 2: /* overlap contains lock: split it */ |
| 454 | if (overlap->lf_start == unlock->lf_start) { |
| 455 | overlap->lf_start = unlock->lf_end + 1; |
| 456 | break; |
| 457 | } |
| 458 | lf_split(overlap, unlock); |
| 459 | overlap->lf_next = unlock->lf_next; |
| 460 | break; |
| 461 | |
| 462 | case 3: /* lock contains overlap */ |
| 463 | *prev = overlap->lf_next; |
| 464 | lf = overlap->lf_next; |
| 465 | free(overlap, M_LOCKF); |
| 466 | continue; |
| 467 | |
| 468 | case 4: /* overlap starts before lock */ |
| 469 | overlap->lf_end = unlock->lf_start - 1; |
| 470 | prev = &overlap->lf_next; |
| 471 | lf = overlap->lf_next; |
| 472 | continue; |
| 473 | |
| 474 | case 5: /* overlap ends after lock */ |
| 475 | overlap->lf_start = unlock->lf_end + 1; |
| 476 | break; |
| 477 | } |
| 478 | break; |
| 479 | } |
| 480 | #ifdef LOCKF_DEBUG |
| 481 | if (lockf_debug & 1) |
| 482 | lf_printlist("lf_clearlock", unlock); |
| 483 | #endif /* LOCKF_DEBUG */ |
| 484 | return (0); |
| 485 | } |
| 486 | |
| 487 | /* |
| 488 | * Check whether there is a blocking lock, |
| 489 | * and if so return its process identifier. |
| 490 | */ |
| 491 | static int |
| 492 | lf_getlock(lock, fl) |
| 493 | struct lockf *lock; |
| 494 | struct flock *fl; |
| 495 | { |
| 496 | struct lockf *block; |
| 497 | |
| 498 | #ifdef LOCKF_DEBUG |
| 499 | if (lockf_debug & 1) |
| 500 | lf_print("lf_getlock", lock); |
| 501 | #endif /* LOCKF_DEBUG */ |
| 502 | |
| 503 | if ((block = lf_getblock(lock))) { |
| 504 | fl->l_type = block->lf_type; |
| 505 | fl->l_whence = SEEK_SET; |
| 506 | fl->l_start = block->lf_start; |
| 507 | if (block->lf_end == -1) |
| 508 | fl->l_len = 0; |
| 509 | else |
| 510 | fl->l_len = block->lf_end - block->lf_start + 1; |
| 511 | if (block->lf_flags & F_POSIX) |
| 512 | fl->l_pid = ((struct proc *)(block->lf_id))->p_pid; |
| 513 | else |
| 514 | fl->l_pid = -1; |
| 515 | } else { |
| 516 | fl->l_type = F_UNLCK; |
| 517 | } |
| 518 | return (0); |
| 519 | } |
| 520 | |
| 521 | /* |
| 522 | * Walk the list of locks for an inode and |
| 523 | * return the first blocking lock. |
| 524 | */ |
| 525 | static struct lockf * |
| 526 | lf_getblock(lock) |
| 527 | struct lockf *lock; |
| 528 | { |
| 529 | struct lockf **prev, *overlap, *lf = *(lock->lf_head); |
| 530 | int ovcase; |
| 531 | |
| 532 | prev = lock->lf_head; |
| 533 | while ((ovcase = lf_findoverlap(lf, lock, OTHERS, &prev, &overlap))) { |
| 534 | /* |
| 535 | * We've found an overlap, see if it blocks us |
| 536 | */ |
| 537 | if ((lock->lf_type == F_WRLCK || overlap->lf_type == F_WRLCK)) |
| 538 | return (overlap); |
| 539 | /* |
| 540 | * Nope, point to the next one on the list and |
| 541 | * see if it blocks us |
| 542 | */ |
| 543 | lf = overlap->lf_next; |
| 544 | } |
| 545 | return (NOLOCKF); |
| 546 | } |
| 547 | |
| 548 | /* |
| 549 | * Walk the list of locks for an inode to |
| 550 | * find an overlapping lock (if any). |
| 551 | * |
| 552 | * NOTE: this returns only the FIRST overlapping lock. There |
| 553 | * may be more than one. |
| 554 | */ |
| 555 | static int |
| 556 | lf_findoverlap(lf, lock, type, prev, overlap) |
| 557 | struct lockf *lf; |
| 558 | struct lockf *lock; |
| 559 | int type; |
| 560 | struct lockf ***prev; |
| 561 | struct lockf **overlap; |
| 562 | { |
| 563 | off_t start, end; |
| 564 | |
| 565 | *overlap = lf; |
| 566 | if (lf == NOLOCKF) |
| 567 | return (0); |
| 568 | #ifdef LOCKF_DEBUG |
| 569 | if (lockf_debug & 2) |
| 570 | lf_print("lf_findoverlap: looking for overlap in", lock); |
| 571 | #endif /* LOCKF_DEBUG */ |
| 572 | start = lock->lf_start; |
| 573 | end = lock->lf_end; |
| 574 | while (lf != NOLOCKF) { |
| 575 | if (((type & SELF) && lf->lf_id != lock->lf_id) || |
| 576 | ((type & OTHERS) && lf->lf_id == lock->lf_id)) { |
| 577 | *prev = &lf->lf_next; |
| 578 | *overlap = lf = lf->lf_next; |
| 579 | continue; |
| 580 | } |
| 581 | #ifdef LOCKF_DEBUG |
| 582 | if (lockf_debug & 2) |
| 583 | lf_print("\tchecking", lf); |
| 584 | #endif /* LOCKF_DEBUG */ |
| 585 | /* |
| 586 | * OK, check for overlap |
| 587 | * |
| 588 | * Six cases: |
| 589 | * 0) no overlap |
| 590 | * 1) overlap == lock |
| 591 | * 2) overlap contains lock |
| 592 | * 3) lock contains overlap |
| 593 | * 4) overlap starts before lock |
| 594 | * 5) overlap ends after lock |
| 595 | */ |
| 596 | if ((lf->lf_end != -1 && start > lf->lf_end) || |
| 597 | (end != -1 && lf->lf_start > end)) { |
| 598 | /* Case 0 */ |
| 599 | #ifdef LOCKF_DEBUG |
| 600 | if (lockf_debug & 2) |
| 601 | printf("no overlap\n"); |
| 602 | #endif /* LOCKF_DEBUG */ |
| 603 | if ((type & SELF) && end != -1 && lf->lf_start > end) |
| 604 | return (0); |
| 605 | *prev = &lf->lf_next; |
| 606 | *overlap = lf = lf->lf_next; |
| 607 | continue; |
| 608 | } |
| 609 | if ((lf->lf_start == start) && (lf->lf_end == end)) { |
| 610 | /* Case 1 */ |
| 611 | #ifdef LOCKF_DEBUG |
| 612 | if (lockf_debug & 2) |
| 613 | printf("overlap == lock\n"); |
| 614 | #endif /* LOCKF_DEBUG */ |
| 615 | return (1); |
| 616 | } |
| 617 | if ((lf->lf_start <= start) && |
| 618 | (end != -1) && |
| 619 | ((lf->lf_end >= end) || (lf->lf_end == -1))) { |
| 620 | /* Case 2 */ |
| 621 | #ifdef LOCKF_DEBUG |
| 622 | if (lockf_debug & 2) |
| 623 | printf("overlap contains lock\n"); |
| 624 | #endif /* LOCKF_DEBUG */ |
| 625 | return (2); |
| 626 | } |
| 627 | if (start <= lf->lf_start && |
| 628 | (end == -1 || |
| 629 | (lf->lf_end != -1 && end >= lf->lf_end))) { |
| 630 | /* Case 3 */ |
| 631 | #ifdef LOCKF_DEBUG |
| 632 | if (lockf_debug & 2) |
| 633 | printf("lock contains overlap\n"); |
| 634 | #endif /* LOCKF_DEBUG */ |
| 635 | return (3); |
| 636 | } |
| 637 | if ((lf->lf_start < start) && |
| 638 | ((lf->lf_end >= start) || (lf->lf_end == -1))) { |
| 639 | /* Case 4 */ |
| 640 | #ifdef LOCKF_DEBUG |
| 641 | if (lockf_debug & 2) |
| 642 | printf("overlap starts before lock\n"); |
| 643 | #endif /* LOCKF_DEBUG */ |
| 644 | return (4); |
| 645 | } |
| 646 | if ((lf->lf_start > start) && |
| 647 | (end != -1) && |
| 648 | ((lf->lf_end > end) || (lf->lf_end == -1))) { |
| 649 | /* Case 5 */ |
| 650 | #ifdef LOCKF_DEBUG |
| 651 | if (lockf_debug & 2) |
| 652 | printf("overlap ends after lock\n"); |
| 653 | #endif /* LOCKF_DEBUG */ |
| 654 | return (5); |
| 655 | } |
| 656 | panic("lf_findoverlap: default"); |
| 657 | } |
| 658 | return (0); |
| 659 | } |
| 660 | |
| 661 | /* |
| 662 | * Split a lock and a contained region into |
| 663 | * two or three locks as necessary. |
| 664 | */ |
| 665 | static void |
| 666 | lf_split(lock1, lock2) |
| 667 | struct lockf *lock1; |
| 668 | struct lockf *lock2; |
| 669 | { |
| 670 | struct lockf *splitlock; |
| 671 | |
| 672 | #ifdef LOCKF_DEBUG |
| 673 | if (lockf_debug & 2) { |
| 674 | lf_print("lf_split", lock1); |
| 675 | lf_print("splitting from", lock2); |
| 676 | } |
| 677 | #endif /* LOCKF_DEBUG */ |
| 678 | /* |
| 679 | * Check to see if spliting into only two pieces. |
| 680 | */ |
| 681 | if (lock1->lf_start == lock2->lf_start) { |
| 682 | lock1->lf_start = lock2->lf_end + 1; |
| 683 | lock2->lf_next = lock1; |
| 684 | return; |
| 685 | } |
| 686 | if (lock1->lf_end == lock2->lf_end) { |
| 687 | lock1->lf_end = lock2->lf_start - 1; |
| 688 | lock2->lf_next = lock1->lf_next; |
| 689 | lock1->lf_next = lock2; |
| 690 | return; |
| 691 | } |
| 692 | /* |
| 693 | * Make a new lock consisting of the last part of |
| 694 | * the encompassing lock |
| 695 | */ |
| 696 | MALLOC(splitlock, struct lockf *, sizeof *splitlock, M_LOCKF, M_WAITOK); |
| 697 | bcopy((caddr_t)lock1, (caddr_t)splitlock, sizeof *splitlock); |
| 698 | splitlock->lf_start = lock2->lf_end + 1; |
| 699 | TAILQ_INIT(&splitlock->lf_blkhd); |
| 700 | lock1->lf_end = lock2->lf_start - 1; |
| 701 | /* |
| 702 | * OK, now link it in |
| 703 | */ |
| 704 | splitlock->lf_next = lock1->lf_next; |
| 705 | lock2->lf_next = splitlock; |
| 706 | lock1->lf_next = lock2; |
| 707 | } |
| 708 | |
| 709 | /* |
| 710 | * Wakeup a blocklist |
| 711 | */ |
| 712 | static void |
| 713 | lf_wakelock(listhead) |
| 714 | struct lockf *listhead; |
| 715 | { |
| 716 | struct lockf *wakelock; |
| 717 | |
| 718 | while (!TAILQ_EMPTY(&listhead->lf_blkhd)) { |
| 719 | wakelock = TAILQ_FIRST(&listhead->lf_blkhd); |
| 720 | TAILQ_REMOVE(&listhead->lf_blkhd, wakelock, lf_block); |
| 721 | wakelock->lf_next = NOLOCKF; |
| 722 | #ifdef LOCKF_DEBUG |
| 723 | if (lockf_debug & 2) |
| 724 | lf_print("lf_wakelock: awakening", wakelock); |
| 725 | #endif /* LOCKF_DEBUG */ |
| 726 | wakeup((caddr_t)wakelock); |
| 727 | } |
| 728 | } |
| 729 | |
| 730 | #ifdef LOCKF_DEBUG |
| 731 | /* |
| 732 | * Print out a lock. |
| 733 | */ |
| 734 | void |
| 735 | lf_print(tag, lock) |
| 736 | char *tag; |
| 737 | struct lockf *lock; |
| 738 | { |
| 739 | |
| 740 | printf("%s: lock %p for ", tag, (void *)lock); |
| 741 | if (lock->lf_flags & F_POSIX) |
| 742 | printf("proc %ld", (long)((struct proc *)lock->lf_id)->p_pid); |
| 743 | else |
| 744 | printf("id %p", (void *)lock->lf_id); |
| 745 | /* XXX no %qd in kernel. Truncate. */ |
| 746 | printf(" in ino %lu on dev <%d, %d>, %s, start %ld, end %ld", |
| 747 | (u_long)lock->lf_inode->i_number, |
| 748 | major(lock->lf_inode->i_dev), |
| 749 | minor(lock->lf_inode->i_dev), |
| 750 | lock->lf_type == F_RDLCK ? "shared" : |
| 751 | lock->lf_type == F_WRLCK ? "exclusive" : |
| 752 | lock->lf_type == F_UNLCK ? "unlock" : |
| 753 | "unknown", (long)lock->lf_start, (long)lock->lf_end); |
| 754 | if (!TAILQ_EMPTY(&lock->lf_blkhd)) |
| 755 | printf(" block %p\n", (void *)TAILQ_FIRST(&lock->lf_blkhd)); |
| 756 | else |
| 757 | printf("\n"); |
| 758 | } |
| 759 | |
| 760 | void |
| 761 | lf_printlist(tag, lock) |
| 762 | char *tag; |
| 763 | struct lockf *lock; |
| 764 | { |
| 765 | struct lockf *lf, *blk; |
| 766 | |
| 767 | printf("%s: Lock list for ino %lu on dev <%d, %d>:\n", |
| 768 | tag, (u_long)lock->lf_inode->i_number, |
| 769 | major(lock->lf_inode->i_dev), |
| 770 | minor(lock->lf_inode->i_dev)); |
| 771 | for (lf = lock->lf_inode->i_lockf; lf; lf = lf->lf_next) { |
| 772 | printf("\tlock %p for ",(void *)lf); |
| 773 | if (lf->lf_flags & F_POSIX) |
| 774 | printf("proc %ld", |
| 775 | (long)((struct proc *)lf->lf_id)->p_pid); |
| 776 | else |
| 777 | printf("id %p", (void *)lf->lf_id); |
| 778 | /* XXX no %qd in kernel. Truncate. */ |
| 779 | printf(", %s, start %ld, end %ld", |
| 780 | lf->lf_type == F_RDLCK ? "shared" : |
| 781 | lf->lf_type == F_WRLCK ? "exclusive" : |
| 782 | lf->lf_type == F_UNLCK ? "unlock" : |
| 783 | "unknown", (long)lf->lf_start, (long)lf->lf_end); |
| 784 | TAILQ_FOREACH(blk, &lf->lf_blkhd, lf_block) { |
| 785 | printf("\n\t\tlock request %p for ", (void *)blk); |
| 786 | if (blk->lf_flags & F_POSIX) |
| 787 | printf("proc %ld", |
| 788 | (long)((struct proc *)blk->lf_id)->p_pid); |
| 789 | else |
| 790 | printf("id %p", (void *)blk->lf_id); |
| 791 | /* XXX no %qd in kernel. Truncate. */ |
| 792 | printf(", %s, start %ld, end %ld", |
| 793 | blk->lf_type == F_RDLCK ? "shared" : |
| 794 | blk->lf_type == F_WRLCK ? "exclusive" : |
| 795 | blk->lf_type == F_UNLCK ? "unlock" : |
| 796 | "unknown", (long)blk->lf_start, |
| 797 | (long)blk->lf_end); |
| 798 | if (!TAILQ_EMPTY(&blk->lf_blkhd)) |
| 799 | panic("lf_printlist: bad list"); |
| 800 | } |
| 801 | printf("\n"); |
| 802 | } |
| 803 | } |
| 804 | #endif /* LOCKF_DEBUG */ |