[unix-history] / sys / ufs / ufs_lockf.c

/*
 * Copyright (c) 1982, 1986, 1989 Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Scooter Morris at Genentech Inc.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *	from: @(#)ufs_lockf.c	7.7 (Berkeley) 7/2/91
 *	$Id: ufs_lockf.c,v 1.4 1993/10/20 07:31:39 davidg Exp $
 */

#include "param.h"
#include "systm.h"
#include "kernel.h"
#include "file.h"
#include "proc.h"
#include "vnode.h"
#include "malloc.h"
#include "fcntl.h"

#include "lockf.h"
#include "quota.h"
#include "inode.h"


/*
 * Advisory record locking support
 */
lf_advlock(head, size, id, op, fl, flags)
	struct lockf **head;
	u_long size;
	caddr_t id;
	int op;
	register struct flock *fl;
	int flags;
{
	register struct lockf *lock;
	off_t start, end;
	int error;

	/*
	 * Avoid the common case of unlocking when inode has no locks.
	 */
	if (*head == (struct lockf *)0) {
		if (op != F_SETLK) {
			fl->l_type = F_UNLCK;
			return (0);
		}
	}

	/*
	 * Convert the flock structure into a start and end.
	 */
	switch (fl->l_whence) {

	case SEEK_SET:
	case SEEK_CUR:
		/*
		 * Caller is responsible for adding any necessary offset
		 * when SEEK_CUR is used.
		 */
		start = fl->l_start;
		break;

	case SEEK_END:
		start = size + fl->l_start;
		break;

	default:
		return (EINVAL);
	}
	if (start < 0)
		return (EINVAL);
	if (fl->l_len == 0)
		end = -1;
	else
		end = start + fl->l_len - 1;
	/*
	 * Create the lockf structure
	 */
	MALLOC(lock, struct lockf *, sizeof *lock, M_LOCKF, M_WAITOK);
	lock->lf_start = start;
	lock->lf_end = end;
	lock->lf_id = id;
	lock->lf_head = head;
	lock->lf_type = fl->l_type;
	lock->lf_next = (struct lockf *)0;
	lock->lf_block = (struct lockf *)0;
	lock->lf_flags = flags;
	/*
	 * Do the requested operation.
	 */
	switch(op) {
	case F_SETLK:
		return (lf_setlock(lock));

	case F_UNLCK:
		error = lf_clearlock(lock);
		FREE(lock, M_LOCKF);
		return (error);

	case F_GETLK:
		error = lf_getlock(lock, fl);
		FREE(lock, M_LOCKF);
		return (error);
	
	default:
		free(lock, M_LOCKF);
		return (EINVAL);
	}
	/* NOTREACHED */
}

/*
 * This variable controls the maximum number of processes that will
 * be checked in doing deadlock detection.
 */
int maxlockdepth = MAXDEPTH;

#ifdef LOCKF_DEBUG
int	lockf_debug = 0;
#endif /* LOCKF_DEBUG */

#define NOLOCKF (struct lockf *)0
#define SELF	0x1
#define OTHERS	0x2

/*
 * Set a byte-range lock.
 */
lf_setlock(lock)
	register struct lockf *lock;
{
	register struct lockf *block;
	struct lockf **head = lock->lf_head;
	struct lockf **prev, *overlap, *ltmp;
	static char lockstr[] = "lockf";
	int ovcase, priority, needtolink, error;

#ifdef LOCKF_DEBUG
	if (lockf_debug & 1)
		lf_print("lf_setlock", lock);
#endif /* LOCKF_DEBUG */

	/*
	 * Set the priority
	 */
	priority = PLOCK;
	if (lock->lf_type == F_WRLCK)
		priority += 4;
	priority |= PCATCH;
	/*
	 * Scan lock list for this file looking for locks that would block us.
	 */
	while (block = lf_getblock(lock)) {
		/*
		 * Free the structure and return if nonblocking.
		 */
		if ((lock->lf_flags & F_WAIT) == 0) {
			FREE(lock, M_LOCKF);
			return (EAGAIN);
		}
		/*
		 * We are blocked. Since flock style locks cover
		 * the whole file, there is no chance for deadlock.
		 * For byte-range locks we must check for deadlock.
		 *
		 * Deadlock detection is done by looking through the
		 * wait channels to see if there are any cycles that
		 * involve us. MAXDEPTH is set just to make sure we
		 * do not go off into neverland.
		 */
		if ((lock->lf_flags & F_POSIX) &&
		    (block->lf_flags & F_POSIX)) {
			register struct proc *wproc;
			register struct lockf *waitblock;
			int i = 0;

			/* The block is waiting on something */
			wproc = (struct proc *)block->lf_id;
			while (wproc->p_wchan &&
			       (wproc->p_wmesg == lockstr) &&
			       (i++ < maxlockdepth)) {
				waitblock = (struct lockf *)wproc->p_wchan;
				/* Get the owner of the blocking lock */
				waitblock = waitblock->lf_next;
				if ((waitblock->lf_flags & F_POSIX) == 0)
					break;
				wproc = (struct proc *)waitblock->lf_id;
				if (wproc == (struct proc *)lock->lf_id) {
					free(lock, M_LOCKF);
					return (EDEADLK);
				}
			}
		}
		/*
		 * For flock type locks, we must first remove
		 * any shared locks that we hold before we sleep
		 * waiting for an exclusive lock.
		 */
		if ((lock->lf_flags & F_FLOCK) &&
		    lock->lf_type == F_WRLCK) {
			lock->lf_type = F_UNLCK;
			(void) lf_clearlock(lock);
			lock->lf_type = F_WRLCK;
		}
		/*
		 * Add our lock to the blocked list and sleep until we're free.
		 * Remember who blocked us (for deadlock detection).
		 */
		lock->lf_next = block;
		lf_addblock(block, lock);
#ifdef LOCKF_DEBUG
		if (lockf_debug & 1) {
			lf_print("lf_setlock: blocking on", block);
			lf_printlist("lf_setlock", block);
		}
#endif /* LOCKF_DEBUG */
		if (error = tsleep((caddr_t)lock, priority, lockstr, 0)) {

#ifdef PK_LOCKF_FIX /* Paul Kranenburg's lockf fix (buggy!) */
			/* Don't leave a dangling pointer in block list */
			if (lf_getblock(lock) == block) {
				struct lockf	**prev;

				/* Still there, find us on list */
				prev = &block->lf_block;
				while ((block = block->lf_block) != NOLOCKF) {
					if (block == lock) {	
						*prev = block->lf_block;
						break;
					}
					prev = &block->lf_block;
				}
			}
			free(lock, M_LOCKF);
#else /* Mark Tinguely's fix instead */
			(void) lf_clearlock(lock);
			return (error);
#endif
#if 0 /* ...and this is the original code -DLG */
			free(lock, M_LOCKF);
#endif
			return (error);
		}
	}
	/*
	 * No blocks!!  Add the lock.  Note that we will
	 * downgrade or upgrade any overlapping locks this
	 * process already owns.
	 *
	 * Skip over locks owned by other processes.
	 * Handle any locks that overlap and are owned by ourselves.
	 */
	prev = head;
	block = *head;
	needtolink = 1;
	for (;;) {
		if (ovcase = lf_findoverlap(block, lock, SELF, &prev, &overlap))
			block = overlap->lf_next;
		/*
		 * Six cases:
		 *	0) no overlap
		 *	1) overlap == lock
		 *	2) overlap contains lock
		 *	3) lock contains overlap
		 *	4) overlap starts before lock
		 *	5) overlap ends after lock
		 */
		switch (ovcase) {
		case 0: /* no overlap */
			if (needtolink) {
				*prev = lock;
				lock->lf_next = overlap;
			}
			break;

		case 1: /* overlap == lock */
			/*
			 * If downgrading lock, others may be
			 * able to acquire it.
			 */
			if (lock->lf_type == F_RDLCK &&
			    overlap->lf_type == F_WRLCK)
				lf_wakelock(overlap);
			overlap->lf_type = lock->lf_type;
			FREE(lock, M_LOCKF);
			lock = overlap; /* for debug output below */
			break;

		case 2: /* overlap contains lock */
			/*
			 * Check for common starting point and different types.
			 */
			if (overlap->lf_type == lock->lf_type) {
				free(lock, M_LOCKF);
				lock = overlap; /* for debug output below */
				break;
			}
			if (overlap->lf_start == lock->lf_start) {
				*prev = lock;
				lock->lf_next = overlap;
				overlap->lf_start = lock->lf_end + 1;
			} else
				lf_split(overlap, lock);
			lf_wakelock(overlap);
			break;

		case 3: /* lock contains overlap */
			/*
			 * If downgrading lock, others may be able to
			 * acquire it, otherwise take the list.
			 */
			if (lock->lf_type == F_RDLCK &&
			    overlap->lf_type == F_WRLCK) {
				lf_wakelock(overlap);
			} else {
				ltmp = lock->lf_block;
				lock->lf_block = overlap->lf_block;
				lf_addblock(lock, ltmp);
			}
			/*
			 * Add the new lock if necessary and delete the overlap.
			 */
			if (needtolink) {
				*prev = lock;
				lock->lf_next = overlap->lf_next;
				prev = &lock->lf_next;
				needtolink = 0;
			} else
				*prev = overlap->lf_next;
			free(overlap, M_LOCKF);
			continue;

		case 4: /* overlap starts before lock */
			/*
			 * Add lock after overlap on the list.
			 */
			lock->lf_next = overlap->lf_next;
			overlap->lf_next = lock;
			overlap->lf_end = lock->lf_start - 1;
			prev = &lock->lf_next;
			lf_wakelock(overlap);
			needtolink = 0;
			continue;

		case 5: /* overlap ends after lock */
			/*
			 * Add the new lock before overlap.
			 */
			if (needtolink) {
				*prev = lock;
				lock->lf_next = overlap;
			}
			overlap->lf_start = lock->lf_end + 1;
			lf_wakelock(overlap);
			break;
		}
		break;
	}
#ifdef LOCKF_DEBUG
	if (lockf_debug & 1) {
		lf_print("lf_setlock: got the lock", lock);
		lf_printlist("lf_setlock", lock);
	}
#endif /* LOCKF_DEBUG */
	return (0);
}

/*
 * Remove a byte-range lock on an inode.
 *
 * Generally, find the lock (or an overlap to that lock)
 * and remove it (or shrink it), then wakeup anyone we can.
 */
lf_clearlock(unlock)
	register struct lockf *unlock;
{
	struct lockf **head = unlock->lf_head;
	register struct lockf *lf = *head;
	struct lockf *overlap, **prev;
	int ovcase;

	if (lf == NOLOCKF)
		return (0);
#ifdef LOCKF_DEBUG
	if (unlock->lf_type != F_UNLCK)
		panic("lf_clearlock: bad type");
	if (lockf_debug & 1)
		lf_print("lf_clearlock", unlock);
#endif /* LOCKF_DEBUG */
	prev = head;
	while (ovcase = lf_findoverlap(lf, unlock, SELF, &prev, &overlap)) {
		/*
		 * Wakeup the list of locks to be retried.
		 */
		lf_wakelock(overlap);

		switch (ovcase) {

		case 1: /* overlap == lock */
			*prev = overlap->lf_next;
			FREE(overlap, M_LOCKF);
			break;

		case 2: /* overlap contains lock: split it */
			if (overlap->lf_start == unlock->lf_start) {
				overlap->lf_start = unlock->lf_end + 1;
				break;
			}
			lf_split(overlap, unlock);
			overlap->lf_next = unlock->lf_next;
			break;

		case 3: /* lock contains overlap */
			*prev = overlap->lf_next;
			lf = overlap->lf_next;
			free(overlap, M_LOCKF);
			continue;

		case 4: /* overlap starts before lock */
			overlap->lf_end = unlock->lf_start - 1;
			prev = &overlap->lf_next;
			lf = overlap->lf_next;
			continue;

		case 5: /* overlap ends after lock */
			overlap->lf_start = unlock->lf_end + 1;
			break;
		}
		break;
	}
#ifdef LOCKF_DEBUG
	if (lockf_debug & 1)
		lf_printlist("lf_clearlock", unlock);
#endif /* LOCKF_DEBUG */
	return (0);
}

/*
 * Check whether there is a blocking lock,
 * and if so return its process identifier.
 */
lf_getlock(lock, fl)
	register struct lockf *lock;
	register struct flock *fl;
{
	register struct lockf *block;
	off_t start, end;

#ifdef LOCKF_DEBUG
	if (lockf_debug & 1)
		lf_print("lf_getlock", lock);
#endif /* LOCKF_DEBUG */

	if (block = lf_getblock(lock)) {
		fl->l_type = block->lf_type;
		fl->l_whence = SEEK_SET;
		fl->l_start = block->lf_start;
		if (block->lf_end == -1)
			fl->l_len = 0;
		else
			fl->l_len = block->lf_end - block->lf_start + 1;
		if (block->lf_flags & F_POSIX)
			fl->l_pid = ((struct proc *)(block->lf_id))->p_pid;
		else
			fl->l_pid = -1;
	} else {
		fl->l_type = F_UNLCK;
	}
	return (0);
}

/*
 * Walk the list of locks for an inode and
 * return the first blocking lock.
 */
struct lockf *
lf_getblock(lock)
	register struct lockf *lock;
{
	struct lockf **prev, *overlap, *lf = *(lock->lf_head);
	int ovcase;

	prev = lock->lf_head;
	while (ovcase = lf_findoverlap(lf, lock, OTHERS, &prev, &overlap)) {
		/*
		 * We've found an overlap, see if it blocks us
		 */
		if ((lock->lf_type == F_WRLCK || overlap->lf_type == F_WRLCK))
			return (overlap);
		/*
		 * Nope, point to the next one on the list and
		 * see if it blocks us
		 */
		lf = overlap->lf_next;
	}
	return (NOLOCKF);
}

/*
 * Walk the list of locks for an inode to
 * find an overlapping lock (if any).
 *
 * NOTE: this returns only the FIRST overlapping lock.  There
 *	 may be more than one.
 */
lf_findoverlap(lf, lock, type, prev, overlap)
	register struct lockf *lf;
	struct lockf *lock;
	int type;
	struct lockf ***prev;
	struct lockf **overlap;
{
	off_t start, end;

	*overlap = lf;
	if (lf == NOLOCKF)
		return (0);
#ifdef LOCKF_DEBUG
	if (lockf_debug & 2)
		lf_print("lf_findoverlap: looking for overlap in", lock);
#endif /* LOCKF_DEBUG */
	start = lock->lf_start;
	end = lock->lf_end;
	while (lf != NOLOCKF) {
		if (((type & SELF) && lf->lf_id != lock->lf_id) ||
		    ((type & OTHERS) && lf->lf_id == lock->lf_id)) {
			*prev = &lf->lf_next;
			*overlap = lf = lf->lf_next;
			continue;
		}
#ifdef LOCKF_DEBUG
		if (lockf_debug & 2)
			lf_print("\tchecking", lf);
#endif /* LOCKF_DEBUG */
		/*
		 * OK, check for overlap
		 *
		 * Six cases:
		 *	0) no overlap
		 *	1) overlap == lock
		 *	2) overlap contains lock
		 *	3) lock contains overlap
		 *	4) overlap starts before lock
		 *	5) overlap ends after lock
		 */
		if ((lf->lf_end != -1 && start > lf->lf_end) ||
		    (end != -1 && lf->lf_start > end)) {
			/* Case 0 */
#ifdef LOCKF_DEBUG
			if (lockf_debug & 2)
				printf("no overlap\n");
#endif /* LOCKF_DEBUG */
			if ((type & SELF) && end != -1 && lf->lf_start > end)
				return (0);
			*prev = &lf->lf_next;
			*overlap = lf = lf->lf_next;
			continue;
		}
		if ((lf->lf_start == start) && (lf->lf_end == end)) {
			/* Case 1 */
#ifdef LOCKF_DEBUG
			if (lockf_debug & 2)
				printf("overlap == lock\n");
#endif /* LOCKF_DEBUG */
			return (1);
		}
		if ((lf->lf_start <= start) &&
		    (end != -1) &&
		    ((lf->lf_end >= end) || (lf->lf_end == -1))) {
			/* Case 2 */
#ifdef LOCKF_DEBUG
			if (lockf_debug & 2)
				printf("overlap contains lock\n");
#endif /* LOCKF_DEBUG */
			return (2);
		}
		if (start <= lf->lf_start &&
			   (end == -1 ||
			   (lf->lf_end != -1 && end >= lf->lf_end))) {
			/* Case 3 */
#ifdef LOCKF_DEBUG
			if (lockf_debug & 2)
				printf("lock contains overlap\n");
#endif /* LOCKF_DEBUG */
			return (3);
		}
		if ((lf->lf_start < start) &&
			((lf->lf_end >= start) || (lf->lf_end == -1))) {
			/* Case 4 */
#ifdef LOCKF_DEBUG
			if (lockf_debug & 2)
				printf("overlap starts before lock\n");
#endif /* LOCKF_DEBUG */
			return (4);
		}
		if ((lf->lf_start > start) &&
			(end != -1) &&
			((lf->lf_end > end) || (lf->lf_end == -1))) {
			/* Case 5 */
#ifdef LOCKF_DEBUG
			if (lockf_debug & 2)
				printf("overlap ends after lock\n");
#endif /* LOCKF_DEBUG */
			return (5);
		}
		panic("lf_findoverlap: default");
	}
	return (0);
}

/*
 * Add a lock to the end of the blocked list.
 */
lf_addblock(lock, blocked)
	struct lockf *lock;
	struct lockf *blocked;
{
	register struct lockf *lf;

	if (blocked == NOLOCKF)
		return;
#ifdef LOCKF_DEBUG
	if (lockf_debug & 2) {
		lf_print("addblock: adding", blocked);
		lf_print("to blocked list of", lock);
	}
#endif /* LOCKF_DEBUG */
	if ((lf = lock->lf_block) == NOLOCKF) {
		lock->lf_block = blocked;
		return;
	}
	while (lf->lf_block != NOLOCKF)
		lf = lf->lf_block;
	lf->lf_block = blocked;
	return;
}

/*
 * Split a lock and a contained region into
 * two or three locks as necessary.
 */
lf_split(lock1, lock2)
	register struct lockf *lock1;
	register struct lockf *lock2;
{
	register struct lockf *splitlock;

#ifdef LOCKF_DEBUG
	if (lockf_debug & 2) {
		lf_print("lf_split", lock1);
		lf_print("splitting from", lock2);
	}
#endif /* LOCKF_DEBUG */
	/*
	 * Check to see if spliting into only two pieces.
	 */
	if (lock1->lf_start == lock2->lf_start) {
		lock1->lf_start = lock2->lf_end + 1;
		lock2->lf_next = lock1;
		return;
	}
	if (lock1->lf_end == lock2->lf_end) {
		lock1->lf_end = lock2->lf_start - 1;
		lock2->lf_next = lock1->lf_next;
		lock1->lf_next = lock2;
		return;
	}
	/*
	 * Make a new lock consisting of the last part of
	 * the encompassing lock
	 */
	MALLOC(splitlock, struct lockf *, sizeof *splitlock, M_LOCKF, M_WAITOK);
	bcopy((caddr_t)lock1, (caddr_t)splitlock, sizeof *splitlock);
	splitlock->lf_start = lock2->lf_end + 1;
	splitlock->lf_block = NOLOCKF;
	lock1->lf_end = lock2->lf_start - 1;
	/*
	 * OK, now link it in
	 */
	splitlock->lf_next = lock1->lf_next;
	lock2->lf_next = splitlock;
	lock1->lf_next = lock2;
}

/*
 * Wakeup a blocklist
 */
lf_wakelock(listhead)
	struct lockf *listhead;
{
	register struct lockf *blocklist, *wakelock;

	blocklist = listhead->lf_block;
	listhead->lf_block = NOLOCKF;
	while (blocklist != NOLOCKF) {
		wakelock = blocklist;
		blocklist = blocklist->lf_block;
		wakelock->lf_block = NOLOCKF;
		wakelock->lf_next = NOLOCKF;
#ifdef LOCKF_DEBUG
		if (lockf_debug & 2)
			lf_print("lf_wakelock: awakening", wakelock);
#endif /* LOCKF_DEBUG */
		wakeup((caddr_t)wakelock);
	}
}

#ifdef LOCKF_DEBUG
/*
 * Print out a lock.
 */
lf_print(tag, lock)
	char *tag;
	register struct lockf *lock;
{
	
	printf("%s: lock 0x%lx for ", tag, lock);
	if (lock->lf_flags & F_POSIX)
		printf("proc %d", ((struct proc *)(lock->lf_id))->p_pid);
	else
		printf("id 0x%x", lock->lf_id);
	printf(" in ino %d on dev <%d, %d>, %s, start %d, end %d",
		lock->lf_inode->i_number,
		major(lock->lf_inode->i_dev),
		minor(lock->lf_inode->i_dev),
		lock->lf_type == F_RDLCK ? "shared" :
		lock->lf_type == F_WRLCK ? "exclusive" :
		lock->lf_type == F_UNLCK ? "unlock" :
		"unknown", lock->lf_start, lock->lf_end);
	if (lock->lf_block)
		printf(" block 0x%x\n", lock->lf_block);
	else
		printf("\n");
}

lf_printlist(tag, lock)
	char *tag;
	struct lockf *lock;
{
	register struct lockf *lf;

	printf("%s: Lock list for ino %d on dev <%d, %d>:\n",
		tag, lock->lf_inode->i_number,
		major(lock->lf_inode->i_dev),
		minor(lock->lf_inode->i_dev));
	for (lf = lock->lf_inode->i_lockf; lf; lf = lf->lf_next) {
		printf("\tlock 0x%lx for ", lf);
		if (lf->lf_flags & F_POSIX)
			printf("proc %d", ((struct proc *)(lf->lf_id))->p_pid);
		else
			printf("id 0x%x", lf->lf_id);
		printf(", %s, start %d, end %d",
			lf->lf_type == F_RDLCK ? "shared" :
			lf->lf_type == F_WRLCK ? "exclusive" :
			lf->lf_type == F_UNLCK ? "unlock" :
			"unknown", lf->lf_start, lf->lf_end);
		if (lf->lf_block)
			printf(" block 0x%x\n", lf->lf_block);
		else
			printf("\n");
	}
}
#endif /* LOCKF_DEBUG */
Commit	Line	Data
15637ed4 RG	1	/*
	2	* Copyright (c) 1982, 1986, 1989 Regents of the University of California.
	3	* 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	*
78ed81a3	36	* from: @(#)ufs_lockf.c 7.7 (Berkeley) 7/2/91
78ed81a3	37	* $Id: ufs_lockf.c,v 1.4 1993/10/20 07:31:39 davidg Exp $
15637ed4 RG	38	*/
	39
	40	#include "param.h"
	41	#include "systm.h"
	42	#include "kernel.h"
	43	#include "file.h"
	44	#include "proc.h"
	45	#include "vnode.h"
	46	#include "malloc.h"
	47	#include "fcntl.h"
	48
	49	#include "lockf.h"
	50	#include "quota.h"
	51	#include "inode.h"
	52
78ed81a3	53
	54
	55	/*
	56	* Advisory record locking support
	57	*/
	58	lf_advlock(head, size, id, op, fl, flags)
	59	struct lockf **head;
	60	u_long size;
	61	caddr_t id;
	62	int op;
	63	register struct flock *fl;
	64	int flags;
	65	{
	66	register struct lockf *lock;
	67	off_t start, end;
	68	int error;
	69
	70	/*
	71	* Avoid the common case of unlocking when inode has no locks.
	72	*/
	73	if (head == (struct lockf )0) {
	74	if (op != F_SETLK) {
	75	fl->l_type = F_UNLCK;
	76	return (0);
	77	}
	78	}
	79
	80	/*
	81	* Convert the flock structure into a start and end.
	82	*/
	83	switch (fl->l_whence) {
	84
	85	case SEEK_SET:
	86	case SEEK_CUR:
	87	/*
	88	* Caller is responsible for adding any necessary offset
	89	* when SEEK_CUR is used.
	90	*/
	91	start = fl->l_start;
	92	break;
	93
	94	case SEEK_END:
	95	start = size + fl->l_start;
	96	break;
	97
	98	default:
	99	return (EINVAL);
	100	}
	101	if (start < 0)
	102	return (EINVAL);
	103	if (fl->l_len == 0)
	104	end = -1;
	105	else
	106	end = start + fl->l_len - 1;
	107	/*
	108	* Create the lockf structure
	109	*/
	110	MALLOC(lock, struct lockf , sizeof lock, M_LOCKF, M_WAITOK);
	111	lock->lf_start = start;
	112	lock->lf_end = end;
	113	lock->lf_id = id;
	114	lock->lf_head = head;
	115	lock->lf_type = fl->l_type;
	116	lock->lf_next = (struct lockf *)0;
117	lock->lf_block = (struct lockf *)0;
118	lock->lf_flags = flags;
119	/*
120	* Do the requested operation.
121	*/
122	switch(op) {
123	case F_SETLK:
124	return (lf_setlock(lock));
125
126	case F_UNLCK:
127	error = lf_clearlock(lock);
128	FREE(lock, M_LOCKF);
129	return (error);
130
131	case F_GETLK:
132	error = lf_getlock(lock, fl);
133	FREE(lock, M_LOCKF);
134	return (error);
135
136	default:
137	free(lock, M_LOCKF);
138	return (EINVAL);
139	}
140	/* NOTREACHED */
141	}
142
15637ed4 RG	143	/*
	144	* This variable controls the maximum number of processes that will
	145	* be checked in doing deadlock detection.
	146	*/
	147	int maxlockdepth = MAXDEPTH;
	148
	149	#ifdef LOCKF_DEBUG
	150	int lockf_debug = 0;
	151	#endif /* LOCKF_DEBUG */
	152
	153	#define NOLOCKF (struct lockf *)0
	154	#define SELF 0x1
	155	#define OTHERS 0x2
	156
	157	/*
	158	* Set a byte-range lock.
	159	*/
	160	lf_setlock(lock)
	161	register struct lockf *lock;
	162	{
	163	register struct lockf *block;
78ed81a3	164	struct lockf **head = lock->lf_head;
15637ed4 RG	165	struct lockf *prev, overlap, *ltmp;
	166	static char lockstr[] = "lockf";
	167	int ovcase, priority, needtolink, error;
	168
	169	#ifdef LOCKF_DEBUG
	170	if (lockf_debug & 1)
	171	lf_print("lf_setlock", lock);
	172	#endif /* LOCKF_DEBUG */
	173
	174	/*
	175	* Set the priority
	176	*/
	177	priority = PLOCK;
	178	if (lock->lf_type == F_WRLCK)
	179	priority += 4;
	180	priority \|= PCATCH;
	181	/*
	182	* Scan lock list for this file looking for locks that would block us.
	183	*/
	184	while (block = lf_getblock(lock)) {
	185	/*
	186	* Free the structure and return if nonblocking.
	187	*/
	188	if ((lock->lf_flags & F_WAIT) == 0) {
	189	FREE(lock, M_LOCKF);
	190	return (EAGAIN);
	191	}
	192	/*
	193	* We are blocked. Since flock style locks cover
	194	* the whole file, there is no chance for deadlock.
	195	* For byte-range locks we must check for deadlock.
	196	*
	197	* Deadlock detection is done by looking through the
	198	* wait channels to see if there are any cycles that
	199	* involve us. MAXDEPTH is set just to make sure we
	200	* do not go off into neverland.
	201	*/
	202	if ((lock->lf_flags & F_POSIX) &&
	203	(block->lf_flags & F_POSIX)) {
	204	register struct proc *wproc;
	205	register struct lockf *waitblock;
	206	int i = 0;
	207
	208	/* The block is waiting on something */
	209	wproc = (struct proc *)block->lf_id;
	210	while (wproc->p_wchan &&
	211	(wproc->p_wmesg == lockstr) &&
	212	(i++ < maxlockdepth)) {
	213	waitblock = (struct lockf *)wproc->p_wchan;
	214	/* Get the owner of the blocking lock */
	215	waitblock = waitblock->lf_next;
	216	if ((waitblock->lf_flags & F_POSIX) == 0)
	217	break;
	218	wproc = (struct proc *)waitblock->lf_id;
	219	if (wproc == (struct proc *)lock->lf_id) {
	220	free(lock, M_LOCKF);
	221	return (EDEADLK);
	222	}
	223	}
	224	}
	225	/*
	226	* For flock type locks, we must first remove
	227	* any shared locks that we hold before we sleep
	228	* waiting for an exclusive lock.
229	*/
230	if ((lock->lf_flags & F_FLOCK) &&
231	lock->lf_type == F_WRLCK) {
232	lock->lf_type = F_UNLCK;
233	(void) lf_clearlock(lock);
234	lock->lf_type = F_WRLCK;
235	}
236	/*
237	* Add our lock to the blocked list and sleep until we're free.
238	* Remember who blocked us (for deadlock detection).
239	*/
240	lock->lf_next = block;
241	lf_addblock(block, lock);
242	#ifdef LOCKF_DEBUG
243	if (lockf_debug & 1) {
244	lf_print("lf_setlock: blocking on", block);
245	lf_printlist("lf_setlock", block);
246	}
247	#endif /* LOCKF_DEBUG */
248	if (error = tsleep((caddr_t)lock, priority, lockstr, 0)) {
249
78ed81a3	250	#ifdef PK_LOCKF_FIX /* Paul Kranenburg's lockf fix (buggy!) */
15637ed4 RG	251	/* Don't leave a dangling pointer in block list */
	252	if (lf_getblock(lock) == block) {
	253	struct lockf **prev;
	254
	255	/* Still there, find us on list */
	256	prev = &block->lf_block;
	257	while ((block = block->lf_block) != NOLOCKF) {
	258	if (block == lock) {
	259	*prev = block->lf_block;
	260	break;
	261	}
	262	prev = &block->lf_block;
	263	}
	264	}
	265	free(lock, M_LOCKF);
78ed81a3	266	#else /* Mark Tinguely's fix instead */
	267	(void) lf_clearlock(lock);
	268	return (error);
	269	#endif
	270	#if 0 /* ...and this is the original code -DLG */
	271	free(lock, M_LOCKF);
	272	#endif
15637ed4 RG	273	return (error);
	274	}
	275	}
	276	/*
	277	* No blocks!! Add the lock. Note that we will
	278	* downgrade or upgrade any overlapping locks this
	279	* process already owns.
	280	*
	281	* Skip over locks owned by other processes.
	282	* Handle any locks that overlap and are owned by ourselves.
	283	*/
78ed81a3	284	prev = head;
78ed81a3	285	block = *head;
15637ed4 RG	286	needtolink = 1;
	287	for (;;) {
	288	if (ovcase = lf_findoverlap(block, lock, SELF, &prev, &overlap))
	289	block = overlap->lf_next;
	290	/*
	291	* Six cases:
	292	* 0) no overlap
	293	* 1) overlap == lock
	294	* 2) overlap contains lock
	295	* 3) lock contains overlap
	296	* 4) overlap starts before lock
	297	* 5) overlap ends after lock
	298	*/
	299	switch (ovcase) {
	300	case 0: /* no overlap */
	301	if (needtolink) {
	302	*prev = lock;
	303	lock->lf_next = overlap;
	304	}
	305	break;
	306
	307	case 1: /* overlap == lock */
	308	/*
	309	* If downgrading lock, others may be
	310	* able to acquire it.
	311	*/
	312	if (lock->lf_type == F_RDLCK &&
	313	overlap->lf_type == F_WRLCK)
	314	lf_wakelock(overlap);
	315	overlap->lf_type = lock->lf_type;
	316	FREE(lock, M_LOCKF);
	317	lock = overlap; /* for debug output below */
	318	break;
	319
	320	case 2: /* overlap contains lock */
	321	/*
	322	* Check for common starting point and different types.
	323	*/
	324	if (overlap->lf_type == lock->lf_type) {
	325	free(lock, M_LOCKF);
	326	lock = overlap; /* for debug output below */
	327	break;
	328	}
	329	if (overlap->lf_start == lock->lf_start) {
	330	*prev = lock;
	331	lock->lf_next = overlap;
	332	overlap->lf_start = lock->lf_end + 1;
	333	} else
	334	lf_split(overlap, lock);
	335	lf_wakelock(overlap);
	336	break;
	337
	338	case 3: /* lock contains overlap */
	339	/*
	340	* If downgrading lock, others may be able to
	341	* acquire it, otherwise take the list.
	342	*/
	343	if (lock->lf_type == F_RDLCK &&
	344	overlap->lf_type == F_WRLCK) {
	345	lf_wakelock(overlap);
	346	} else {
	347	ltmp = lock->lf_block;
	348	lock->lf_block = overlap->lf_block;
	349	lf_addblock(lock, ltmp);
350	}
351	/*
352	* Add the new lock if necessary and delete the overlap.
353	*/
354	if (needtolink) {
355	*prev = lock;
356	lock->lf_next = overlap->lf_next;
357	prev = &lock->lf_next;
358	needtolink = 0;
359	} else
360	*prev = overlap->lf_next;
361	free(overlap, M_LOCKF);
362	continue;
363
364	case 4: /* overlap starts before lock */
365	/*
366	* Add lock after overlap on the list.
367	*/
368	lock->lf_next = overlap->lf_next;
369	overlap->lf_next = lock;
370	overlap->lf_end = lock->lf_start - 1;
371	prev = &lock->lf_next;
372	lf_wakelock(overlap);
373	needtolink = 0;
374	continue;
375
376	case 5: /* overlap ends after lock */
377	/*
378	* Add the new lock before overlap.
379	*/
380	if (needtolink) {
381	*prev = lock;
382	lock->lf_next = overlap;
383	}
384	overlap->lf_start = lock->lf_end + 1;
385	lf_wakelock(overlap);
386	break;
387	}
388	break;
389	}
390	#ifdef LOCKF_DEBUG
391	if (lockf_debug & 1) {
392	lf_print("lf_setlock: got the lock", lock);
393	lf_printlist("lf_setlock", lock);
394	}
395	#endif /* LOCKF_DEBUG */
396	return (0);
397	}
398
399	/*
400	* Remove a byte-range lock on an inode.
401	*
402	* Generally, find the lock (or an overlap to that lock)
403	* and remove it (or shrink it), then wakeup anyone we can.
404	*/
405	lf_clearlock(unlock)
406	register struct lockf *unlock;
407	{
78ed81a3	408	struct lockf **head = unlock->lf_head;
78ed81a3	409	register struct lockf lf = head;
15637ed4 RG	410	struct lockf overlap, *prev;
	411	int ovcase;
	412
	413	if (lf == NOLOCKF)
	414	return (0);
	415	#ifdef LOCKF_DEBUG
	416	if (unlock->lf_type != F_UNLCK)
	417	panic("lf_clearlock: bad type");
	418	if (lockf_debug & 1)
	419	lf_print("lf_clearlock", unlock);
	420	#endif /* LOCKF_DEBUG */
78ed81a3	421	prev = head;
15637ed4 RG	422	while (ovcase = lf_findoverlap(lf, unlock, SELF, &prev, &overlap)) {
	423	/*
	424	* Wakeup the list of locks to be retried.
	425	*/
	426	lf_wakelock(overlap);
	427
	428	switch (ovcase) {
	429
	430	case 1: /* overlap == lock */
	431	*prev = overlap->lf_next;
	432	FREE(overlap, M_LOCKF);
	433	break;
	434
	435	case 2: /* overlap contains lock: split it */
	436	if (overlap->lf_start == unlock->lf_start) {
	437	overlap->lf_start = unlock->lf_end + 1;
	438	break;
	439	}
	440	lf_split(overlap, unlock);
	441	overlap->lf_next = unlock->lf_next;
	442	break;
	443
	444	case 3: /* lock contains overlap */
	445	*prev = overlap->lf_next;
	446	lf = overlap->lf_next;
	447	free(overlap, M_LOCKF);
	448	continue;
	449
	450	case 4: /* overlap starts before lock */
	451	overlap->lf_end = unlock->lf_start - 1;
	452	prev = &overlap->lf_next;
	453	lf = overlap->lf_next;
	454	continue;
	455
	456	case 5: /* overlap ends after lock */
	457	overlap->lf_start = unlock->lf_end + 1;
	458	break;
	459	}
	460	break;
	461	}
	462	#ifdef LOCKF_DEBUG
	463	if (lockf_debug & 1)
	464	lf_printlist("lf_clearlock", unlock);
	465	#endif /* LOCKF_DEBUG */
	466	return (0);
	467	}
	468
	469	/*
	470	* Check whether there is a blocking lock,
	471	* and if so return its process identifier.
	472	*/
	473	lf_getlock(lock, fl)
	474	register struct lockf *lock;
	475	register struct flock *fl;
	476	{
	477	register struct lockf *block;
	478	off_t start, end;
	479
	480	#ifdef LOCKF_DEBUG
	481	if (lockf_debug & 1)
	482	lf_print("lf_getlock", lock);
	483	#endif /* LOCKF_DEBUG */
	484
	485	if (block = lf_getblock(lock)) {
486	fl->l_type = block->lf_type;
487	fl->l_whence = SEEK_SET;
488	fl->l_start = block->lf_start;
489	if (block->lf_end == -1)
490	fl->l_len = 0;
491	else
492	fl->l_len = block->lf_end - block->lf_start + 1;
493	if (block->lf_flags & F_POSIX)
494	fl->l_pid = ((struct proc *)(block->lf_id))->p_pid;
495	else
496	fl->l_pid = -1;
497	} else {
498	fl->l_type = F_UNLCK;
499	}
500	return (0);
501	}
502
503	/*
504	* Walk the list of locks for an inode and
505	* return the first blocking lock.
506	*/
507	struct lockf *
508	lf_getblock(lock)
509	register struct lockf *lock;
510	{
78ed81a3	511	struct lockf *prev, overlap, lf = (lock->lf_head);
15637ed4 RG	512	int ovcase;
15637ed4 RG	513
78ed81a3	514	prev = lock->lf_head;
15637ed4 RG	515	while (ovcase = lf_findoverlap(lf, lock, OTHERS, &prev, &overlap)) {
	516	/*
	517	* We've found an overlap, see if it blocks us
	518	*/
	519	if ((lock->lf_type == F_WRLCK \|\| overlap->lf_type == F_WRLCK))
	520	return (overlap);
	521	/*
	522	* Nope, point to the next one on the list and
	523	* see if it blocks us
	524	*/
	525	lf = overlap->lf_next;
	526	}
	527	return (NOLOCKF);
	528	}
	529
	530	/*
	531	* Walk the list of locks for an inode to
	532	* find an overlapping lock (if any).
	533	*
	534	* NOTE: this returns only the FIRST overlapping lock. There
	535	* may be more than one.
	536	*/
	537	lf_findoverlap(lf, lock, type, prev, overlap)
	538	register struct lockf *lf;
	539	struct lockf *lock;
	540	int type;
	541	struct lockf ***prev;
	542	struct lockf **overlap;
	543	{
	544	off_t start, end;
	545
	546	*overlap = lf;
	547	if (lf == NOLOCKF)
	548	return (0);
	549	#ifdef LOCKF_DEBUG
	550	if (lockf_debug & 2)
	551	lf_print("lf_findoverlap: looking for overlap in", lock);
	552	#endif /* LOCKF_DEBUG */
	553	start = lock->lf_start;
	554	end = lock->lf_end;
	555	while (lf != NOLOCKF) {
	556	if (((type & SELF) && lf->lf_id != lock->lf_id) \|\|
	557	((type & OTHERS) && lf->lf_id == lock->lf_id)) {
	558	*prev = &lf->lf_next;
	559	*overlap = lf = lf->lf_next;
	560	continue;
	561	}
	562	#ifdef LOCKF_DEBUG
	563	if (lockf_debug & 2)
	564	lf_print("\tchecking", lf);
	565	#endif /* LOCKF_DEBUG */
	566	/*
	567	* OK, check for overlap
	568	*
	569	* Six cases:
	570	* 0) no overlap
	571	* 1) overlap == lock
	572	* 2) overlap contains lock
	573	* 3) lock contains overlap
	574	* 4) overlap starts before lock
	575	* 5) overlap ends after lock
	576	*/
	577	if ((lf->lf_end != -1 && start > lf->lf_end) \|\|
	578	(end != -1 && lf->lf_start > end)) {
579	/* Case 0 */
580	#ifdef LOCKF_DEBUG
581	if (lockf_debug & 2)
582	printf("no overlap\n");
583	#endif /* LOCKF_DEBUG */
584	if ((type & SELF) && end != -1 && lf->lf_start > end)
585	return (0);
586	*prev = &lf->lf_next;
587	*overlap = lf = lf->lf_next;
588	continue;
589	}
590	if ((lf->lf_start == start) && (lf->lf_end == end)) {
591	/* Case 1 */
592	#ifdef LOCKF_DEBUG
593	if (lockf_debug & 2)
594	printf("overlap == lock\n");
595	#endif /* LOCKF_DEBUG */
596	return (1);
597	}
598	if ((lf->lf_start <= start) &&
599	(end != -1) &&
600	((lf->lf_end >= end) \|\| (lf->lf_end == -1))) {
601	/* Case 2 */
602	#ifdef LOCKF_DEBUG
603	if (lockf_debug & 2)
604	printf("overlap contains lock\n");
605	#endif /* LOCKF_DEBUG */
606	return (2);
607	}
608	if (start <= lf->lf_start &&
78ed81a3	609	(end == -1 \|\|
15637ed4 RG	610	(lf->lf_end != -1 && end >= lf->lf_end))) {
	611	/* Case 3 */
	612	#ifdef LOCKF_DEBUG
	613	if (lockf_debug & 2)
	614	printf("lock contains overlap\n");
	615	#endif /* LOCKF_DEBUG */
	616	return (3);
	617	}
	618	if ((lf->lf_start < start) &&
	619	((lf->lf_end >= start) \|\| (lf->lf_end == -1))) {
	620	/* Case 4 */
	621	#ifdef LOCKF_DEBUG
	622	if (lockf_debug & 2)
	623	printf("overlap starts before lock\n");
	624	#endif /* LOCKF_DEBUG */
	625	return (4);
	626	}
	627	if ((lf->lf_start > start) &&
	628	(end != -1) &&
	629	((lf->lf_end > end) \|\| (lf->lf_end == -1))) {
	630	/* Case 5 */
	631	#ifdef LOCKF_DEBUG
	632	if (lockf_debug & 2)
	633	printf("overlap ends after lock\n");
	634	#endif /* LOCKF_DEBUG */
	635	return (5);
	636	}
	637	panic("lf_findoverlap: default");
	638	}
	639	return (0);
	640	}
	641
	642	/*
	643	* Add a lock to the end of the blocked list.
	644	*/
	645	lf_addblock(lock, blocked)
	646	struct lockf *lock;
	647	struct lockf *blocked;
	648	{
	649	register struct lockf *lf;
	650
	651	if (blocked == NOLOCKF)
	652	return;
	653	#ifdef LOCKF_DEBUG
	654	if (lockf_debug & 2) {
	655	lf_print("addblock: adding", blocked);
	656	lf_print("to blocked list of", lock);
	657	}
	658	#endif /* LOCKF_DEBUG */
	659	if ((lf = lock->lf_block) == NOLOCKF) {
	660	lock->lf_block = blocked;
	661	return;
	662	}
	663	while (lf->lf_block != NOLOCKF)
	664	lf = lf->lf_block;
	665	lf->lf_block = blocked;
	666	return;
	667	}
	668
	669	/*
	670	* Split a lock and a contained region into
	671	* two or three locks as necessary.
	672	*/
	673	lf_split(lock1, lock2)
674	register struct lockf *lock1;
675	register struct lockf *lock2;
676	{
677	register struct lockf *splitlock;
678
679	#ifdef LOCKF_DEBUG
680	if (lockf_debug & 2) {
681	lf_print("lf_split", lock1);
682	lf_print("splitting from", lock2);
683	}
684	#endif /* LOCKF_DEBUG */
685	/*
686	* Check to see if spliting into only two pieces.
687	*/
688	if (lock1->lf_start == lock2->lf_start) {
689	lock1->lf_start = lock2->lf_end + 1;
690	lock2->lf_next = lock1;
691	return;
692	}
693	if (lock1->lf_end == lock2->lf_end) {
694	lock1->lf_end = lock2->lf_start - 1;
695	lock2->lf_next = lock1->lf_next;
696	lock1->lf_next = lock2;
697	return;
698	}
699	/*
700	* Make a new lock consisting of the last part of
701	* the encompassing lock
702	*/
703	MALLOC(splitlock, struct lockf , sizeof splitlock, M_LOCKF, M_WAITOK);
704	bcopy((caddr_t)lock1, (caddr_t)splitlock, sizeof *splitlock);
705	splitlock->lf_start = lock2->lf_end + 1;
706	splitlock->lf_block = NOLOCKF;
707	lock1->lf_end = lock2->lf_start - 1;
708	/*
709	* OK, now link it in
710	*/
711	splitlock->lf_next = lock1->lf_next;
712	lock2->lf_next = splitlock;
713	lock1->lf_next = lock2;
714	}
715
716	/*
717	* Wakeup a blocklist
718	*/
719	lf_wakelock(listhead)
720	struct lockf *listhead;
721	{
78ed81a3	722	register struct lockf blocklist, wakelock;
15637ed4 RG	723
	724	blocklist = listhead->lf_block;
	725	listhead->lf_block = NOLOCKF;
78ed81a3	726	while (blocklist != NOLOCKF) {
	727	wakelock = blocklist;
	728	blocklist = blocklist->lf_block;
15637ed4 RG	729	wakelock->lf_block = NOLOCKF;
	730	wakelock->lf_next = NOLOCKF;
	731	#ifdef LOCKF_DEBUG
	732	if (lockf_debug & 2)
	733	lf_print("lf_wakelock: awakening", wakelock);
	734	#endif /* LOCKF_DEBUG */
78ed81a3	735	wakeup((caddr_t)wakelock);
78ed81a3	736	}
15637ed4 RG	737	}
	738
	739	#ifdef LOCKF_DEBUG
	740	/*
	741	* Print out a lock.
	742	*/
	743	lf_print(tag, lock)
	744	char *tag;
	745	register struct lockf *lock;
	746	{
	747
	748	printf("%s: lock 0x%lx for ", tag, lock);
	749	if (lock->lf_flags & F_POSIX)
	750	printf("proc %d", ((struct proc *)(lock->lf_id))->p_pid);
	751	else
	752	printf("id 0x%x", lock->lf_id);
	753	printf(" in ino %d on dev <%d, %d>, %s, start %d, end %d",
	754	lock->lf_inode->i_number,
	755	major(lock->lf_inode->i_dev),
	756	minor(lock->lf_inode->i_dev),
	757	lock->lf_type == F_RDLCK ? "shared" :
	758	lock->lf_type == F_WRLCK ? "exclusive" :
	759	lock->lf_type == F_UNLCK ? "unlock" :
	760	"unknown", lock->lf_start, lock->lf_end);
	761	if (lock->lf_block)
	762	printf(" block 0x%x\n", lock->lf_block);
	763	else
	764	printf("\n");
	765	}
	766
	767	lf_printlist(tag, lock)
	768	char *tag;
	769	struct lockf *lock;
	770	{
	771	register struct lockf *lf;
	772
	773	printf("%s: Lock list for ino %d on dev <%d, %d>:\n",
	774	tag, lock->lf_inode->i_number,
	775	major(lock->lf_inode->i_dev),
	776	minor(lock->lf_inode->i_dev));
	777	for (lf = lock->lf_inode->i_lockf; lf; lf = lf->lf_next) {
	778	printf("\tlock 0x%lx for ", lf);
	779	if (lf->lf_flags & F_POSIX)
	780	printf("proc %d", ((struct proc *)(lf->lf_id))->p_pid);
	781	else
	782	printf("id 0x%x", lf->lf_id);
	783	printf(", %s, start %d, end %d",
	784	lf->lf_type == F_RDLCK ? "shared" :
	785	lf->lf_type == F_WRLCK ? "exclusive" :
	786	lf->lf_type == F_UNLCK ? "unlock" :
	787	"unknown", lf->lf_start, lf->lf_end);
	788	if (lf->lf_block)
	789	printf(" block 0x%x\n", lf->lf_block);
	790	else
	791	printf("\n");
	792	}
	793	}
	794	#endif /* LOCKF_DEBUG */