+++ /dev/null
-/*
- * Copyright (c) 1999,2001-2002 Apple Computer, Inc. All rights reserved.
- *
- * @APPLE_LICENSE_HEADER_START@
- *
- * The contents of this file constitute Original Code as defined in and
- * are subject to the Apple Public Source License Version 1.1 (the
- * "License"). You may not use this file except in compliance with the
- * License. Please obtain a copy of the License at
- * http://www.apple.com/publicsource and read it before using this file.
- *
- * This Original Code and all software distributed under the License are
- * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
- * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
- * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the
- * License for the specific language governing rights and limitations
- * under the License.
- *
- * @APPLE_LICENSE_HEADER_END@
- */
-
-/* (c) 1997-1998,2001 Apple Computer, Inc. All Rights Reserved */
-/*
- * Copyright (c) 1982, 1986, 1989, 1993
- * The 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.
- *
- * @(#)hfs_lockf.c 1.0
- * derived from @(#)ufs_lockf.c 8.4 (Berkeley) 10/26/94
- */
-
-#include <sys/param.h>
-#include <sys/systm.h>
-#include <sys/kernel.h>
-#include <sys/file.h>
-#include <sys/proc.h>
-#include <sys/vnode.h>
-#include <sys/malloc.h>
-#include <sys/fcntl.h>
-
-#include "hfs_cnode.h"
-#include "hfs_lockf.h"
-
-/*
- * This variable controls the maximum number of processes that will
- * be checked in doing deadlock detection.
- */
-int hfsmaxlockdepth = MAXDEPTH;
-
-#ifdef LOCKF_DEBUG
-#include <vm/vm.h>
-#include <sys/sysctl.h>
-int lockf_debug = 0;
-struct ctldebug debug4 = { "lockf_debug", &lockf_debug };
-#endif
-
-#define NOLOCKF (struct hfslockf *)0
-#define SELF 0x1
-#define OTHERS 0x2
-
-/*
- * Set a byte-range lock.
- */
-int
-hfs_setlock(lock)
- register struct hfslockf *lock;
-{
- register struct hfslockf *block;
- struct filefork *fork = lock->lf_fork;
- struct hfslockf **prev, *overlap, *ltmp;
- static char lockstr[] = "hfslockf";
- int ovcase, priority, needtolink, error;
-
-#ifdef LOCKF_DEBUG
- if (lockf_debug & 1)
- hfs_lprint("hfs_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 = hfs_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 hfslockf *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++ < hfsmaxlockdepth)) {
- waitblock = (struct hfslockf *)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) hfs_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;
- TAILQ_INSERT_TAIL(&block->lf_blkhd, lock, lf_block);
-#ifdef LOCKF_DEBUG
- if (lockf_debug & 1) {
- hfs_lprint("hfs_setlock: blocking on", block);
- hfs_lprintlist("hfs_setlock", block);
- }
-#endif /* LOCKF_DEBUG */
- if ((error = tsleep((caddr_t)lock, priority, lockstr, 0))) {
- /*
- * We may have been awakened by a signal (in
- * which case we must remove ourselves from the
- * blocked list) and/or by another process
- * releasing a lock (in which case we have already
- * been removed from the blocked list and our
- * lf_next field set to NOLOCKF).
- */
- if (lock->lf_next)
- TAILQ_REMOVE(&lock->lf_next->lf_blkhd, lock,
- lf_block);
- _FREE(lock, M_LOCKF);
- 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 = &fork->ff_lockf;
- block = fork->ff_lockf;
- needtolink = 1;
- for (;;) {
- if ((ovcase = hfs_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)
- hfs_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
- hfs_split(overlap, lock);
- hfs_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) {
- hfs_wakelock(overlap);
- } else {
- while ((ltmp = overlap->lf_blkhd.tqh_first)) {
- TAILQ_REMOVE(&overlap->lf_blkhd, ltmp,
- lf_block);
- TAILQ_INSERT_TAIL(&lock->lf_blkhd,
- ltmp, lf_block);
- }
- }
- /*
- * 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;
- hfs_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;
- hfs_wakelock(overlap);
- break;
- }
- break;
- }
-#ifdef LOCKF_DEBUG
- if (lockf_debug & 1) {
- hfs_lprint("hfs_setlock: got the lock", lock);
- hfs_lprintlist("hfs_setlock", lock);
- }
-#endif /* LOCKF_DEBUG */
- return (0);
-}
-
-/*
- * Remove a file fork's byte-range lock.
- *
- * Generally, find the lock (or an overlap to that lock)
- * and remove it (or shrink it), then wakeup anyone we can.
- */
-int
-hfs_clearlock(unlock)
- register struct hfslockf *unlock;
-{
- struct filefork *fork = unlock->lf_fork;
- register struct hfslockf *lf = fork->ff_lockf;
- struct hfslockf *overlap, **prev;
- int ovcase;
-
- if (lf == NOLOCKF)
- return (0);
-#ifdef LOCKF_DEBUG
- if (unlock->lf_type != F_UNLCK)
- panic("hfs_clearlock: bad type");
- if (lockf_debug & 1)
- hfs_lprint("hfs_clearlock", unlock);
-#endif /* LOCKF_DEBUG */
- prev = &fork->ff_lockf;
- while ((ovcase = hfs_findoverlap(lf, unlock, SELF, &prev, &overlap))) {
- /*
- * Wakeup the list of locks to be retried.
- */
- hfs_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;
- }
- hfs_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)
- hfs_lprintlist("hfs_clearlock", unlock);
-#endif /* LOCKF_DEBUG */
- return (0);
-}
-
-/*
- * Check whether there is a blocking lock,
- * and if so return its process identifier.
- */
-int
-hfs_getlock(lock, fl)
- register struct hfslockf *lock;
- register struct flock *fl;
-{
- register struct hfslockf *block;
-
-#ifdef LOCKF_DEBUG
- if (lockf_debug & 1)
- hfs_lprint("hfs_getlock", lock);
-#endif /* LOCKF_DEBUG */
-
- if ((block = hfs_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 a file fork's list of locks and
- * return the first blocking lock.
- */
-struct hfslockf *
-hfs_getblock(lock)
- register struct hfslockf *lock;
-{
- struct hfslockf **prev, *overlap, *lf = lock->lf_fork->ff_lockf;
- int ovcase;
-
- prev = &lock->lf_fork->ff_lockf;
- while ((ovcase = hfs_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 a file fork's list of locks to
- * find an overlapping lock (if any).
- *
- * NOTE: this returns only the FIRST overlapping lock. There
- * may be more than one.
- */
-int
-hfs_findoverlap(lf, lock, type, prev, overlap)
- register struct hfslockf *lf;
- struct hfslockf *lock;
- int type;
- struct hfslockf ***prev;
- struct hfslockf **overlap;
-{
- off_t start, end;
-
- *overlap = lf;
- if (lf == NOLOCKF)
- return (0);
-#ifdef LOCKF_DEBUG
- if (lockf_debug & 2)
- hfs_lprint("hfs_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)
- hfs_lprint("\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("hfs_findoverlap: default");
- }
- return (0);
-}
-
-/*
- * Split a lock and a contained region into
- * two or three locks as necessary.
- */
-void
-hfs_split(lock1, lock2)
- register struct hfslockf *lock1;
- register struct hfslockf *lock2;
-{
- register struct hfslockf *splitlock;
-
-#ifdef LOCKF_DEBUG
- if (lockf_debug & 2) {
- hfs_lprint("hfs_split", lock1);
- hfs_lprint("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 hfslockf *, sizeof *splitlock, M_LOCKF, M_WAITOK);
- bcopy((caddr_t)lock1, (caddr_t)splitlock, sizeof *splitlock);
- splitlock->lf_start = lock2->lf_end + 1;
- TAILQ_INIT(&splitlock->lf_blkhd);
- 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
- */
-void
-hfs_wakelock(listhead)
- struct hfslockf *listhead;
-{
- register struct hfslockf *wakelock;
-
- while ((wakelock = listhead->lf_blkhd.tqh_first)) {
- TAILQ_REMOVE(&listhead->lf_blkhd, wakelock, lf_block);
- wakelock->lf_next = NOLOCKF;
-#ifdef LOCKF_DEBUG
- if (lockf_debug & 2)
- hfs_lprint("hfs_wakelock: awakening", wakelock);
-#endif /* LOCKF_DEBUG */
- wakeup((caddr_t)wakelock);
- }
-}
-
-#ifdef LOCKF_DEBUG
-/*
- * Print out a lock.
- */
-hfs_lprint(tag, lock)
- char *tag;
- register struct hfslockf *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",
- FTOC(lock->lf_fork)->c_fileid,
- major(FTOC(lock->lf_fork)->c_dev),
- minor(FTOC(lock->lf_fork)->c_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_blkhd.tqh_first)
- printf(" block 0x%x\n", lock->lf_blkhd.tqh_first);
- else
- printf("\n");
-}
-
-hfs_lprintlist(tag, lock)
- char *tag;
- struct hfslockf *lock;
-{
- register struct hfslockf *lf, *blk;
-
- printf("%s: Lock list for ino %d on dev <%d, %d>:\n",
- tag, FTOC(lock->lf_fork)->i_number,
- major(FTOC(lock->lf_fork)->c_dev),
- minor(FTOC(lock->lf_fork)->c_dev));
- for (lf = lock->lf_fork->ff_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);
- for (blk = lf->lf_blkhd.tqh_first; blk;
- blk = blk->lf_block.tqe_next) {
- printf("\n\t\tlock request 0x%lx for ", blk);
- if (blk->lf_flags & F_POSIX)
- printf("proc %d",
- ((struct proc *)(blk->lf_id))->p_pid);
- else
- printf("id 0x%x", blk->lf_id);
- printf(", %s, start %d, end %d",
- blk->lf_type == F_RDLCK ? "shared" :
- blk->lf_type == F_WRLCK ? "exclusive" :
- blk->lf_type == F_UNLCK ? "unlock" :
- "unknown", blk->lf_start, blk->lf_end);
- if (blk->lf_blkhd.tqh_first)
- panic("hfs_lprintlist: bad list");
- }
- printf("\n");
- }
-}
-#endif /* LOCKF_DEBUG */
projects / apple / xnu.git / blobdiff