xref: /freebsd/sys/kern/kern_lockf.c (revision a316b26e50bbed7cf655fbba726ab87d8ab7599d)
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  * $Id: kern_lockf.c,v 1.2 1994/09/25 19:33:37 phk Exp $
38  */
39 
40 #include <sys/param.h>
41 #include <sys/systm.h>
42 #include <sys/kernel.h>
43 #include <sys/file.h>
44 #include <sys/proc.h>
45 #include <sys/vnode.h>
46 #include <sys/malloc.h>
47 #include <sys/fcntl.h>
48 
49 #include <sys/lockf.h>
50 
51 /*
52  * This variable controls the maximum number of processes that will
53  * be checked in doing deadlock detection.
54  */
55 int maxlockdepth = MAXDEPTH;
56 
57 #ifdef LOCKF_DEBUG
58 int	lockf_debug = 0;
59 #endif
60 
61 #define NOLOCKF (struct lockf *)0
62 #define SELF	0x1
63 #define OTHERS	0x2
64 
65 /*
66  * Advisory record locking support
67  */
68 int
69 lf_advlock(ap, head, size)
70 	struct vop_advlock_args /* {
71 		struct vnode *a_vp;
72 		caddr_t  a_id;
73 		int  a_op;
74 		struct flock *a_fl;
75 		int  a_flags;
76 	} */ *ap;
77 	struct lockf **head;
78 	u_quad_t size;
79 {
80 	register struct flock *fl = ap->a_fl;
81 	register struct lockf *lock;
82 	off_t start, end;
83 	int error;
84 
85 	/*
86 	 * Avoid the common case of unlocking when inode has no locks.
87 	 */
88 	if (*head == (struct lockf *)0) {
89 		if (ap->a_op != F_SETLK) {
90 			fl->l_type = F_UNLCK;
91 			return (0);
92 		}
93 	}
94 	/*
95 	 * Convert the flock structure into a start and end.
96 	 */
97 	switch (fl->l_whence) {
98 
99 	case SEEK_SET:
100 	case SEEK_CUR:
101 		/*
102 		 * Caller is responsible for adding any necessary offset
103 		 * when SEEK_CUR is used.
104 		 */
105 		start = fl->l_start;
106 		break;
107 
108 	case SEEK_END:
109 		start = size + fl->l_start;
110 		break;
111 
112 	default:
113 		return (EINVAL);
114 	}
115 	if (start < 0)
116 		return (EINVAL);
117 	if (fl->l_len == 0)
118 		end = -1;
119 	else
120 		end = start + fl->l_len - 1;
121 	/*
122 	 * Create the lockf structure
123 	 */
124 	MALLOC(lock, struct lockf *, sizeof *lock, M_LOCKF, M_WAITOK);
125 	lock->lf_start = start;
126 	lock->lf_end = end;
127 	lock->lf_id = ap->a_id;
128 	lock->lf_head = head;
129 	lock->lf_type = fl->l_type;
130 	lock->lf_next = (struct lockf *)0;
131 	lock->lf_block = (struct lockf *)0;
132 	lock->lf_flags = ap->a_flags;
133 	/*
134 	 * Do the requested operation.
135 	 */
136 	switch(ap->a_op) {
137 	case F_SETLK:
138 		return (lf_setlock(lock));
139 
140 	case F_UNLCK:
141 		error = lf_clearlock(lock);
142 		FREE(lock, M_LOCKF);
143 		return (error);
144 
145 	case F_GETLK:
146 		error = lf_getlock(lock, fl);
147 		FREE(lock, M_LOCKF);
148 		return (error);
149 
150 	default:
151 		free(lock, M_LOCKF);
152 		return (EINVAL);
153 	}
154 	/* NOTREACHED */
155 }
156 
157 /*
158  * Set a byte-range lock.
159  */
160 int
161 lf_setlock(lock)
162 	register struct lockf *lock;
163 {
164 	register struct lockf *block;
165 	struct lockf **head = lock->lf_head;
166 	struct lockf **prev, *overlap, *ltmp;
167 	static char lockstr[] = "lockf";
168 	int ovcase, priority, needtolink, error;
169 
170 #ifdef LOCKF_DEBUG
171 	if (lockf_debug & 1)
172 		lf_print("lf_setlock", lock);
173 #endif /* LOCKF_DEBUG */
174 
175 	/*
176 	 * Set the priority
177 	 */
178 	priority = PLOCK;
179 	if (lock->lf_type == F_WRLCK)
180 		priority += 4;
181 	priority |= PCATCH;
182 	/*
183 	 * Scan lock list for this file looking for locks that would block us.
184 	 */
185 	while ((block = lf_getblock(lock))) {
186 		/*
187 		 * Free the structure and return if nonblocking.
188 		 */
189 		if ((lock->lf_flags & F_WAIT) == 0) {
190 			FREE(lock, M_LOCKF);
191 			return (EAGAIN);
192 		}
193 		/*
194 		 * We are blocked. Since flock style locks cover
195 		 * the whole file, there is no chance for deadlock.
196 		 * For byte-range locks we must check for deadlock.
197 		 *
198 		 * Deadlock detection is done by looking through the
199 		 * wait channels to see if there are any cycles that
200 		 * involve us. MAXDEPTH is set just to make sure we
201 		 * do not go off into neverland.
202 		 */
203 		if ((lock->lf_flags & F_POSIX) &&
204 		    (block->lf_flags & F_POSIX)) {
205 			register struct proc *wproc;
206 			register struct lockf *waitblock;
207 			int i = 0;
208 
209 			/* The block is waiting on something */
210 			wproc = (struct proc *)block->lf_id;
211 			while (wproc->p_wchan &&
212 			       (wproc->p_wmesg == lockstr) &&
213 			       (i++ < maxlockdepth)) {
214 				waitblock = (struct lockf *)wproc->p_wchan;
215 				/* Get the owner of the blocking lock */
216 				waitblock = waitblock->lf_next;
217 				if ((waitblock->lf_flags & F_POSIX) == 0)
218 					break;
219 				wproc = (struct proc *)waitblock->lf_id;
220 				if (wproc == (struct proc *)lock->lf_id) {
221 					free(lock, M_LOCKF);
222 					return (EDEADLK);
223 				}
224 			}
225 		}
226 		/*
227 		 * For flock type locks, we must first remove
228 		 * any shared locks that we hold before we sleep
229 		 * waiting for an exclusive lock.
230 		 */
231 		if ((lock->lf_flags & F_FLOCK) &&
232 		    lock->lf_type == F_WRLCK) {
233 			lock->lf_type = F_UNLCK;
234 			(void) lf_clearlock(lock);
235 			lock->lf_type = F_WRLCK;
236 		}
237 		/*
238 		 * Add our lock to the blocked list and sleep until we're free.
239 		 * Remember who blocked us (for deadlock detection).
240 		 */
241 		lock->lf_next = block;
242 		lf_addblock(block, lock);
243 #ifdef LOCKF_DEBUG
244 		if (lockf_debug & 1) {
245 			lf_print("lf_setlock: blocking on", block);
246 			lf_printlist("lf_setlock", block);
247 		}
248 #endif /* LOCKF_DEBUG */
249 		if ((error = tsleep((caddr_t)lock, priority, lockstr, 0))) {
250 			/*
251 			 * Delete ourselves from the waiting to lock list.
252 			 */
253 			for (block = lock->lf_next;
254 			     block != NOLOCKF;
255 			     block = block->lf_block) {
256 				if (block->lf_block != lock)
257 					continue;
258 				block->lf_block = block->lf_block->lf_block;
259 				break;
260 			}
261 			/*
262 			 * If we did not find ourselves on the list, but
263 			 * are still linked onto a lock list, then something
264 			 * is very wrong.
265 			 */
266 			if (block == NOLOCKF && lock->lf_next != NOLOCKF)
267 				panic("lf_setlock: lost lock");
268 			free(lock, M_LOCKF);
269 			return (error);
270 		}
271 	}
272 	/*
273 	 * No blocks!!  Add the lock.  Note that we will
274 	 * downgrade or upgrade any overlapping locks this
275 	 * process already owns.
276 	 *
277 	 * Skip over locks owned by other processes.
278 	 * Handle any locks that overlap and are owned by ourselves.
279 	 */
280 	prev = head;
281 	block = *head;
282 	needtolink = 1;
283 	for (;;) {
284 		ovcase = lf_findoverlap(block, lock, SELF, &prev, &overlap);
285 		if (ovcase)
286 			block = overlap->lf_next;
287 		/*
288 		 * Six cases:
289 		 *	0) no overlap
290 		 *	1) overlap == lock
291 		 *	2) overlap contains lock
292 		 *	3) lock contains overlap
293 		 *	4) overlap starts before lock
294 		 *	5) overlap ends after lock
295 		 */
296 		switch (ovcase) {
297 		case 0: /* no overlap */
298 			if (needtolink) {
299 				*prev = lock;
300 				lock->lf_next = overlap;
301 			}
302 			break;
303 
304 		case 1: /* overlap == lock */
305 			/*
306 			 * If downgrading lock, others may be
307 			 * able to acquire it.
308 			 */
309 			if (lock->lf_type == F_RDLCK &&
310 			    overlap->lf_type == F_WRLCK)
311 				lf_wakelock(overlap);
312 			overlap->lf_type = lock->lf_type;
313 			FREE(lock, M_LOCKF);
314 			lock = overlap; /* for debug output below */
315 			break;
316 
317 		case 2: /* overlap contains lock */
318 			/*
319 			 * Check for common starting point and different types.
320 			 */
321 			if (overlap->lf_type == lock->lf_type) {
322 				free(lock, M_LOCKF);
323 				lock = overlap; /* for debug output below */
324 				break;
325 			}
326 			if (overlap->lf_start == lock->lf_start) {
327 				*prev = lock;
328 				lock->lf_next = overlap;
329 				overlap->lf_start = lock->lf_end + 1;
330 			} else
331 				lf_split(overlap, lock);
332 			lf_wakelock(overlap);
333 			break;
334 
335 		case 3: /* lock contains overlap */
336 			/*
337 			 * If downgrading lock, others may be able to
338 			 * acquire it, otherwise take the list.
339 			 */
340 			if (lock->lf_type == F_RDLCK &&
341 			    overlap->lf_type == F_WRLCK) {
342 				lf_wakelock(overlap);
343 			} else {
344 				ltmp = lock->lf_block;
345 				lock->lf_block = overlap->lf_block;
346 				lf_addblock(lock, ltmp);
347 			}
348 			/*
349 			 * Add the new lock if necessary and delete the overlap.
350 			 */
351 			if (needtolink) {
352 				*prev = lock;
353 				lock->lf_next = overlap->lf_next;
354 				prev = &lock->lf_next;
355 				needtolink = 0;
356 			} else
357 				*prev = overlap->lf_next;
358 			free(overlap, M_LOCKF);
359 			continue;
360 
361 		case 4: /* overlap starts before lock */
362 			/*
363 			 * Add lock after overlap on the list.
364 			 */
365 			lock->lf_next = overlap->lf_next;
366 			overlap->lf_next = lock;
367 			overlap->lf_end = lock->lf_start - 1;
368 			prev = &lock->lf_next;
369 			lf_wakelock(overlap);
370 			needtolink = 0;
371 			continue;
372 
373 		case 5: /* overlap ends after lock */
374 			/*
375 			 * Add the new lock before overlap.
376 			 */
377 			if (needtolink) {
378 				*prev = lock;
379 				lock->lf_next = overlap;
380 			}
381 			overlap->lf_start = lock->lf_end + 1;
382 			lf_wakelock(overlap);
383 			break;
384 		}
385 		break;
386 	}
387 #ifdef LOCKF_DEBUG
388 	if (lockf_debug & 1) {
389 		lf_print("lf_setlock: got the lock", lock);
390 		lf_printlist("lf_setlock", lock);
391 	}
392 #endif /* LOCKF_DEBUG */
393 	return (0);
394 }
395 
396 /*
397  * Remove a byte-range lock on an inode.
398  *
399  * Generally, find the lock (or an overlap to that lock)
400  * and remove it (or shrink it), then wakeup anyone we can.
401  */
402 int
403 lf_clearlock(unlock)
404 	register struct lockf *unlock;
405 {
406 	struct lockf **head = unlock->lf_head;
407 	register struct lockf *lf = *head;
408 	struct lockf *overlap, **prev;
409 	int ovcase;
410 
411 	if (lf == NOLOCKF)
412 		return (0);
413 #ifdef LOCKF_DEBUG
414 	if (unlock->lf_type != F_UNLCK)
415 		panic("lf_clearlock: bad type");
416 	if (lockf_debug & 1)
417 		lf_print("lf_clearlock", unlock);
418 #endif /* LOCKF_DEBUG */
419 	prev = head;
420 	while ((ovcase = lf_findoverlap(lf, unlock, SELF, &prev, &overlap))) {
421 		/*
422 		 * Wakeup the list of locks to be retried.
423 		 */
424 		lf_wakelock(overlap);
425 
426 		switch (ovcase) {
427 
428 		case 1: /* overlap == lock */
429 			*prev = overlap->lf_next;
430 			FREE(overlap, M_LOCKF);
431 			break;
432 
433 		case 2: /* overlap contains lock: split it */
434 			if (overlap->lf_start == unlock->lf_start) {
435 				overlap->lf_start = unlock->lf_end + 1;
436 				break;
437 			}
438 			lf_split(overlap, unlock);
439 			overlap->lf_next = unlock->lf_next;
440 			break;
441 
442 		case 3: /* lock contains overlap */
443 			*prev = overlap->lf_next;
444 			lf = overlap->lf_next;
445 			free(overlap, M_LOCKF);
446 			continue;
447 
448 		case 4: /* overlap starts before lock */
449 			overlap->lf_end = unlock->lf_start - 1;
450 			prev = &overlap->lf_next;
451 			lf = overlap->lf_next;
452 			continue;
453 
454 		case 5: /* overlap ends after lock */
455 			overlap->lf_start = unlock->lf_end + 1;
456 			break;
457 		}
458 		break;
459 	}
460 #ifdef LOCKF_DEBUG
461 	if (lockf_debug & 1)
462 		lf_printlist("lf_clearlock", unlock);
463 #endif /* LOCKF_DEBUG */
464 	return (0);
465 }
466 
467 /*
468  * Check whether there is a blocking lock,
469  * and if so return its process identifier.
470  */
471 int
472 lf_getlock(lock, fl)
473 	register struct lockf *lock;
474 	register struct flock *fl;
475 {
476 	register struct lockf *block;
477 
478 #ifdef LOCKF_DEBUG
479 	if (lockf_debug & 1)
480 		lf_print("lf_getlock", lock);
481 #endif /* LOCKF_DEBUG */
482 
483 	if ((block = lf_getblock(lock))) {
484 		fl->l_type = block->lf_type;
485 		fl->l_whence = SEEK_SET;
486 		fl->l_start = block->lf_start;
487 		if (block->lf_end == -1)
488 			fl->l_len = 0;
489 		else
490 			fl->l_len = block->lf_end - block->lf_start + 1;
491 		if (block->lf_flags & F_POSIX)
492 			fl->l_pid = ((struct proc *)(block->lf_id))->p_pid;
493 		else
494 			fl->l_pid = -1;
495 	} else {
496 		fl->l_type = F_UNLCK;
497 	}
498 	return (0);
499 }
500 
501 /*
502  * Walk the list of locks for an inode and
503  * return the first blocking lock.
504  */
505 struct lockf *
506 lf_getblock(lock)
507 	register struct lockf *lock;
508 {
509 	struct lockf **prev, *overlap, *lf = *(lock->lf_head);
510 	int ovcase;
511 
512 	prev = lock->lf_head;
513 	while ((ovcase = lf_findoverlap(lf, lock, OTHERS, &prev, &overlap))) {
514 		/*
515 		 * We've found an overlap, see if it blocks us
516 		 */
517 		if ((lock->lf_type == F_WRLCK || overlap->lf_type == F_WRLCK))
518 			return (overlap);
519 		/*
520 		 * Nope, point to the next one on the list and
521 		 * see if it blocks us
522 		 */
523 		lf = overlap->lf_next;
524 	}
525 	return (NOLOCKF);
526 }
527 
528 /*
529  * Walk the list of locks for an inode to
530  * find an overlapping lock (if any).
531  *
532  * NOTE: this returns only the FIRST overlapping lock.  There
533  *	 may be more than one.
534  */
535 int
536 lf_findoverlap(lf, lock, type, prev, overlap)
537 	register struct lockf *lf;
538 	struct lockf *lock;
539 	int type;
540 	struct lockf ***prev;
541 	struct lockf **overlap;
542 {
543 	off_t start, end;
544 
545 	*overlap = lf;
546 	if (lf == NOLOCKF)
547 		return (0);
548 #ifdef LOCKF_DEBUG
549 	if (lockf_debug & 2)
550 		lf_print("lf_findoverlap: looking for overlap in", lock);
551 #endif /* LOCKF_DEBUG */
552 	start = lock->lf_start;
553 	end = lock->lf_end;
554 	while (lf != NOLOCKF) {
555 		if (((type & SELF) && lf->lf_id != lock->lf_id) ||
556 		    ((type & OTHERS) && lf->lf_id == lock->lf_id)) {
557 			*prev = &lf->lf_next;
558 			*overlap = lf = lf->lf_next;
559 			continue;
560 		}
561 #ifdef LOCKF_DEBUG
562 		if (lockf_debug & 2)
563 			lf_print("\tchecking", lf);
564 #endif /* LOCKF_DEBUG */
565 		/*
566 		 * OK, check for overlap
567 		 *
568 		 * Six cases:
569 		 *	0) no overlap
570 		 *	1) overlap == lock
571 		 *	2) overlap contains lock
572 		 *	3) lock contains overlap
573 		 *	4) overlap starts before lock
574 		 *	5) overlap ends after lock
575 		 */
576 		if ((lf->lf_end != -1 && start > lf->lf_end) ||
577 		    (end != -1 && lf->lf_start > end)) {
578 			/* Case 0 */
579 #ifdef LOCKF_DEBUG
580 			if (lockf_debug & 2)
581 				printf("no overlap\n");
582 #endif /* LOCKF_DEBUG */
583 			if ((type & SELF) && end != -1 && lf->lf_start > end)
584 				return (0);
585 			*prev = &lf->lf_next;
586 			*overlap = lf = lf->lf_next;
587 			continue;
588 		}
589 		if ((lf->lf_start == start) && (lf->lf_end == end)) {
590 			/* Case 1 */
591 #ifdef LOCKF_DEBUG
592 			if (lockf_debug & 2)
593 				printf("overlap == lock\n");
594 #endif /* LOCKF_DEBUG */
595 			return (1);
596 		}
597 		if ((lf->lf_start <= start) &&
598 		    (end != -1) &&
599 		    ((lf->lf_end >= end) || (lf->lf_end == -1))) {
600 			/* Case 2 */
601 #ifdef LOCKF_DEBUG
602 			if (lockf_debug & 2)
603 				printf("overlap contains lock\n");
604 #endif /* LOCKF_DEBUG */
605 			return (2);
606 		}
607 		if (start <= lf->lf_start &&
608 		           (end == -1 ||
609 			   (lf->lf_end != -1 && end >= lf->lf_end))) {
610 			/* Case 3 */
611 #ifdef LOCKF_DEBUG
612 			if (lockf_debug & 2)
613 				printf("lock contains overlap\n");
614 #endif /* LOCKF_DEBUG */
615 			return (3);
616 		}
617 		if ((lf->lf_start < start) &&
618 			((lf->lf_end >= start) || (lf->lf_end == -1))) {
619 			/* Case 4 */
620 #ifdef LOCKF_DEBUG
621 			if (lockf_debug & 2)
622 				printf("overlap starts before lock\n");
623 #endif /* LOCKF_DEBUG */
624 			return (4);
625 		}
626 		if ((lf->lf_start > start) &&
627 			(end != -1) &&
628 			((lf->lf_end > end) || (lf->lf_end == -1))) {
629 			/* Case 5 */
630 #ifdef LOCKF_DEBUG
631 			if (lockf_debug & 2)
632 				printf("overlap ends after lock\n");
633 #endif /* LOCKF_DEBUG */
634 			return (5);
635 		}
636 		panic("lf_findoverlap: default");
637 	}
638 	return (0);
639 }
640 
641 /*
642  * Add a lock to the end of the blocked list.
643  */
644 void
645 lf_addblock(blocklist, lock)
646 	struct lockf *blocklist;
647 	struct lockf *lock;
648 {
649 	register struct lockf *lf;
650 
651 	if (lock == NOLOCKF)
652 		return;
653 #ifdef LOCKF_DEBUG
654 	if (lockf_debug & 2) {
655 		lf_print("addblock: adding", lock);
656 		lf_print("to blocked list of", blocklist);
657 	}
658 #endif /* LOCKF_DEBUG */
659 	if ((lf = blocklist->lf_block) == NOLOCKF) {
660 		blocklist->lf_block = lock;
661 		return;
662 	}
663 	while (lf->lf_block != NOLOCKF)
664 		lf = lf->lf_block;
665 	lf->lf_block = lock;
666 	return;
667 }
668 
669 /*
670  * Split a lock and a contained region into
671  * two or three locks as necessary.
672  */
673 void
674 lf_split(lock1, lock2)
675 	register struct lockf *lock1;
676 	register struct lockf *lock2;
677 {
678 	register struct lockf *splitlock;
679 
680 #ifdef LOCKF_DEBUG
681 	if (lockf_debug & 2) {
682 		lf_print("lf_split", lock1);
683 		lf_print("splitting from", lock2);
684 	}
685 #endif /* LOCKF_DEBUG */
686 	/*
687 	 * Check to see if spliting into only two pieces.
688 	 */
689 	if (lock1->lf_start == lock2->lf_start) {
690 		lock1->lf_start = lock2->lf_end + 1;
691 		lock2->lf_next = lock1;
692 		return;
693 	}
694 	if (lock1->lf_end == lock2->lf_end) {
695 		lock1->lf_end = lock2->lf_start - 1;
696 		lock2->lf_next = lock1->lf_next;
697 		lock1->lf_next = lock2;
698 		return;
699 	}
700 	/*
701 	 * Make a new lock consisting of the last part of
702 	 * the encompassing lock
703 	 */
704 	MALLOC(splitlock, struct lockf *, sizeof *splitlock, M_LOCKF, M_WAITOK);
705 	bcopy((caddr_t)lock1, (caddr_t)splitlock, sizeof *splitlock);
706 	splitlock->lf_start = lock2->lf_end + 1;
707 	splitlock->lf_block = NOLOCKF;
708 	lock1->lf_end = lock2->lf_start - 1;
709 	/*
710 	 * OK, now link it in
711 	 */
712 	splitlock->lf_next = lock1->lf_next;
713 	lock2->lf_next = splitlock;
714 	lock1->lf_next = lock2;
715 }
716 
717 /*
718  * Wakeup a blocklist
719  */
720 void
721 lf_wakelock(listhead)
722 	struct lockf *listhead;
723 {
724         register struct lockf *blocklist, *wakelock;
725 
726 	blocklist = listhead->lf_block;
727 	listhead->lf_block = NOLOCKF;
728         while (blocklist != NOLOCKF) {
729                 wakelock = blocklist;
730                 blocklist = blocklist->lf_block;
731 		wakelock->lf_block = NOLOCKF;
732 		wakelock->lf_next = NOLOCKF;
733 #ifdef LOCKF_DEBUG
734 		if (lockf_debug & 2)
735 			lf_print("lf_wakelock: awakening", wakelock);
736 #endif /* LOCKF_DEBUG */
737                 wakeup((caddr_t)wakelock);
738         }
739 }
740 
741 #ifdef LOCKF_DEBUG
742 /*
743  * Print out a lock.
744  */
745 void
746 lf_print(tag, lock)
747 	char *tag;
748 	register struct lockf *lock;
749 {
750 
751 	printf("%s: lock 0x%lx for ", tag, lock);
752 	if (lock->lf_flags & F_POSIX)
753 		printf("proc %d", ((struct proc *)(lock->lf_id))->p_pid);
754 	else
755 		printf("id 0x%x", lock->lf_id);
756 	printf(" in ino %d on dev <%d, %d>, %s, start %d, end %d",
757 		lock->lf_inode->i_number,
758 		major(lock->lf_inode->i_dev),
759 		minor(lock->lf_inode->i_dev),
760 		lock->lf_type == F_RDLCK ? "shared" :
761 		lock->lf_type == F_WRLCK ? "exclusive" :
762 		lock->lf_type == F_UNLCK ? "unlock" :
763 		"unknown", lock->lf_start, lock->lf_end);
764 	if (lock->lf_block)
765 		printf(" block 0x%x\n", lock->lf_block);
766 	else
767 		printf("\n");
768 }
769 
770 void
771 lf_printlist(tag, lock)
772 	char *tag;
773 	struct lockf *lock;
774 {
775 	register struct lockf *lf;
776 
777 	printf("%s: Lock list for ino %d on dev <%d, %d>:\n",
778 		tag, lock->lf_inode->i_number,
779 		major(lock->lf_inode->i_dev),
780 		minor(lock->lf_inode->i_dev));
781 	for (lf = lock->lf_inode->i_lockf; lf; lf = lf->lf_next) {
782 		printf("\tlock 0x%lx for ", lf);
783 		if (lf->lf_flags & F_POSIX)
784 			printf("proc %d", ((struct proc *)(lf->lf_id))->p_pid);
785 		else
786 			printf("id 0x%x", lf->lf_id);
787 		printf(", %s, start %d, end %d",
788 			lf->lf_type == F_RDLCK ? "shared" :
789 			lf->lf_type == F_WRLCK ? "exclusive" :
790 			lf->lf_type == F_UNLCK ? "unlock" :
791 			"unknown", lf->lf_start, lf->lf_end);
792 		if (lf->lf_block)
793 			printf(" block 0x%x\n", lf->lf_block);
794 		else
795 			printf("\n");
796 	}
797 }
798 #endif /* LOCKF_DEBUG */
799