File: [local] / sys / kern / vfs_lockf.c (download)
Revision 1.1.1.1 (vendor branch), Tue Mar 4 16:15:04 2008 UTC (16 years, 2 months ago) by nbrk
Branch: OPENBSD_4_2_BASE, MAIN
CVS Tags: jornada-partial-support-wip, HEAD Changes since 1.1: +0 -0 lines
Import of OpenBSD 4.2 release kernel tree with initial code to support
Jornada 720/728, StrongARM 1110-based handheld PC.
At this point kernel roots on NFS and boots into vfs_mountroot() and traps.
What is supported:
- glass console, Jornada framebuffer (jfb) works in 16bpp direct color mode
(needs some palette tweaks for non black/white/blue colors, i think)
- saic, SA11x0 interrupt controller (needs cleanup)
- sacom, SA11x0 UART (supported only as boot console for now)
- SA11x0 GPIO controller fully supported (but can't handle multiple interrupt
handlers on one gpio pin)
- sassp, SSP port on SA11x0 that attaches spibus
- Jornada microcontroller (jmcu) to control kbd, battery, etc throught
the SPI bus (wskbd attaches on jmcu, but not tested)
- tod functions seem work
- initial code for SA-1111 (chip companion) : this is TODO
Next important steps, i think:
- gpio and intc on sa1111
- pcmcia support for sa11x0 (and sa1111 help logic)
- REAL root on nfs when we have PCMCIA support (we may use any of supported pccard NICs)
- root on wd0! (using already supported PCMCIA-ATA)
|
/* $OpenBSD: vfs_lockf.c,v 1.12 2005/11/20 21:55:15 pedro Exp $ */
/* $NetBSD: vfs_lockf.c,v 1.7 1996/02/04 02:18:21 christos Exp $ */
/*
* 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. 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.
*
* @(#)ufs_lockf.c 8.3 (Berkeley) 1/6/94
*/
#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/pool.h>
#include <sys/fcntl.h>
#include <sys/lockf.h>
struct pool lockfpool;
/*
* This variable controls the maximum number of processes that will
* be checked in doing deadlock detection.
*/
int maxlockdepth = MAXDEPTH;
#define SELF 0x1
#define OTHERS 0x2
#ifdef LOCKF_DEBUG
#define DEBUG_SETLOCK 0x01
#define DEBUG_CLEARLOCK 0x02
#define DEBUG_GETLOCK 0x04
#define DEBUG_FINDOVR 0x08
#define DEBUG_SPLIT 0x10
#define DEBUG_WAKELOCK 0x20
int lockf_debug = DEBUG_SETLOCK|DEBUG_CLEARLOCK|DEBUG_WAKELOCK;
#define DPRINTF(args, level) if (lockf_debug & (level)) printf args
#else
#define DPRINTF(args, level)
#endif
void
lf_init(void)
{
pool_init(&lockfpool, sizeof(struct lockf), 0, 0, 0,
"lockfpl", &pool_allocator_nointr);
}
struct lockf *lf_alloc(uid_t, int);
void lf_free(struct lockf *);
/*
* We enforce a limit on locks by uid, so that a single user cannot
* run the kernel out of memory. For now, the limit is pretty coarse.
* There is no limit on root.
*
* Splitting a lock will always succeed, regardless of current allocations.
* If you're slightly above the limit, we still have to permit an allocation
* so that the unlock can succeed. If the unlocking causes too many splits,
* however, you're totally cutoff.
*/
int maxlocksperuid = 1024;
/*
* 3 options for allowfail.
* 0 - always allocate. 1 - cutoff at limit. 2 - cutoff at double limit.
*/
struct lockf *
lf_alloc(uid_t uid, int allowfail)
{
struct uidinfo *uip;
struct lockf *lock;
uip = uid_find(uid);
if (uid && allowfail && uip->ui_lockcnt >
(allowfail == 1 ? maxlocksperuid : (maxlocksperuid * 2)))
return (NULL);
uip->ui_lockcnt++;
lock = pool_get(&lockfpool, PR_WAITOK);
lock->lf_uid = uid;
return (lock);
}
void
lf_free(struct lockf *lock)
{
struct uidinfo *uip;
uip = uid_find(lock->lf_uid);
uip->ui_lockcnt--;
pool_put(&lockfpool, lock);
}
/*
* Do an advisory lock operation.
*/
int
lf_advlock(struct lockf **head, off_t size, caddr_t id, int op,
struct flock *fl, int flags)
{
struct proc *p = curproc;
struct lockf *lock;
off_t start, end;
int error;
/*
* 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;
if (end < start)
return (EINVAL);
}
/*
* Avoid the common case of unlocking when inode has no locks.
*/
if (*head == NULL) {
if (op != F_SETLK) {
fl->l_type = F_UNLCK;
return (0);
}
}
/*
* Create the lockf structure.
*/
lock = lf_alloc(p->p_ucred->cr_uid, op != F_UNLCK ? 1 : 2);
if (!lock)
return (ENOMEM);
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 = NULL;
TAILQ_INIT(&lock->lf_blkhd);
lock->lf_flags = flags;
/*
* Do the requested operation.
*/
switch (op) {
case F_SETLK:
return (lf_setlock(lock));
case F_UNLCK:
error = lf_clearlock(lock);
lf_free(lock);
return (error);
case F_GETLK:
error = lf_getlock(lock, fl);
lf_free(lock);
return (error);
default:
lf_free(lock);
return (EINVAL);
}
/* NOTREACHED */
}
/*
* Set a byte-range lock.
*/
int
lf_setlock(struct lockf *lock)
{
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 & DEBUG_SETLOCK)
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)) != NULL) {
/*
* Free the structure and return if nonblocking.
*/
if ((lock->lf_flags & F_WAIT) == 0) {
lf_free(lock);
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)) {
struct proc *wproc;
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) {
lf_free(lock);
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;
#ifdef LOCKF_DEBUG
if (lockf_debug & DEBUG_SETLOCK) {
lf_print("lf_setlock", lock);
lf_print("lf_setlock: blocking on", block);
}
#endif /* LOCKF_DEBUG */
TAILQ_INSERT_TAIL(&block->lf_blkhd, lock, lf_block);
error = tsleep(lock, priority, lockstr, 0);
#if 0
if (error) {
/*
* Delete ourselves from the waiting to lock list.
*/
TAILQ_REMOVE(&lock->lf_next->lf_blkhd, lock, lf_block);
lf_free(lock);
return (error);
}
#else
if (lock->lf_next != NULL) {
TAILQ_REMOVE(&lock->lf_next->lf_blkhd, lock, lf_block);
lock->lf_next = NULL;
}
if (error) {
lf_free(lock);
return (error);
}
#endif
}
/*
* 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 (;;) {
ovcase = lf_findoverlap(block, lock, SELF, &prev, &overlap);
if (ovcase)
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;
lf_free(lock);
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) {
lf_free(lock);
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 {
while ((ltmp =
TAILQ_FIRST(&overlap->lf_blkhd))) {
TAILQ_REMOVE(&overlap->lf_blkhd, ltmp,
lf_block);
ltmp->lf_next = lock;
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;
lf_free(overlap);
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 & DEBUG_SETLOCK) {
lf_print("lf_setlock: got the lock", 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.
*/
int
lf_clearlock(struct lockf *lock)
{
struct lockf **head = lock->lf_head;
struct lockf *lf = *head;
struct lockf *overlap, **prev;
int ovcase;
if (lf == NULL)
return (0);
#ifdef LOCKF_DEBUG
if (lockf_debug & DEBUG_CLEARLOCK)
lf_print("lf_clearlock", lock);
#endif /* LOCKF_DEBUG */
prev = head;
while ((ovcase = lf_findoverlap(lf, lock, SELF,
&prev, &overlap)) != 0) {
/*
* Wakeup the list of locks to be retried.
*/
lf_wakelock(overlap);
switch (ovcase) {
case 1: /* overlap == lock */
*prev = overlap->lf_next;
lf_free(overlap);
break;
case 2: /* overlap contains lock: split it */
if (overlap->lf_start == lock->lf_start) {
overlap->lf_start = lock->lf_end + 1;
break;
}
lf_split(overlap, lock);
overlap->lf_next = lock->lf_next;
break;
case 3: /* lock contains overlap */
*prev = overlap->lf_next;
lf = overlap->lf_next;
lf_free(overlap);
continue;
case 4: /* overlap starts before lock */
overlap->lf_end = lock->lf_start - 1;
prev = &overlap->lf_next;
lf = overlap->lf_next;
continue;
case 5: /* overlap ends after lock */
overlap->lf_start = lock->lf_end + 1;
break;
}
break;
}
return (0);
}
/*
* Check whether there is a blocking lock,
* and if so return its process identifier.
*/
int
lf_getlock(struct lockf *lock, struct flock *fl)
{
struct lockf *block;
#ifdef LOCKF_DEBUG
if (lockf_debug & DEBUG_CLEARLOCK)
lf_print("lf_getlock", lock);
#endif /* LOCKF_DEBUG */
if ((block = lf_getblock(lock)) != NULL) {
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(struct lockf *lock)
{
struct lockf **prev, *overlap, *lf;
prev = lock->lf_head;
lf = *prev;
while (lf_findoverlap(lf, lock, OTHERS, &prev, &overlap) != 0) {
/*
* 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 (NULL);
}
/*
* 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.
*/
int
lf_findoverlap(struct lockf *lf, struct lockf *lock, int type,
struct lockf ***prev, struct lockf **overlap)
{
off_t start, end;
#ifdef LOCKF_DEBUG
if (lf && lockf_debug & DEBUG_FINDOVR)
lf_print("lf_findoverlap: looking for overlap in", lock);
#endif /* LOCKF_DEBUG */
*overlap = lf;
start = lock->lf_start;
end = lock->lf_end;
while (lf != NULL) {
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 & DEBUG_FINDOVR)
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
*/
/* Case 0 */
if ((lf->lf_end != -1 && start > lf->lf_end) ||
(end != -1 && lf->lf_start > end)) {
DPRINTF(("no overlap\n"), DEBUG_FINDOVR);
if ((type & SELF) && end != -1 && lf->lf_start > end)
return (0);
*prev = &lf->lf_next;
*overlap = lf = lf->lf_next;
continue;
}
/* Case 1 */
if ((lf->lf_start == start) && (lf->lf_end == end)) {
DPRINTF(("overlap == lock\n"), DEBUG_FINDOVR);
return (1);
}
/* Case 2 */
if ((lf->lf_start <= start) &&
(lf->lf_end == -1 ||
(end != -1 && lf->lf_end >= end))) {
DPRINTF(("overlap contains lock\n"), DEBUG_FINDOVR);
return (2);
}
/* Case 3 */
if (start <= lf->lf_start &&
(end == -1 ||
(lf->lf_end != -1 && end >= lf->lf_end))) {
DPRINTF(("lock contains overlap\n"), DEBUG_FINDOVR);
return (3);
}
/* Case 4 */
if ((lf->lf_start < start) &&
((lf->lf_end >= start) || (lf->lf_end == -1))) {
DPRINTF(("overlap starts before lock\n"),
DEBUG_FINDOVR);
return (4);
}
/* Case 5 */
if ((lf->lf_start > start) &&
(end != -1) &&
((lf->lf_end > end) || (lf->lf_end == -1))) {
DPRINTF(("overlap ends after lock\n"), DEBUG_FINDOVR);
return (5);
}
panic("lf_findoverlap: default");
}
return (0);
}
/*
* Split a lock and a contained region into
* two or three locks as necessary.
*/
void
lf_split(struct lockf *lock1, struct lockf *lock2)
{
struct lockf *splitlock;
#ifdef LOCKF_DEBUG
if (lockf_debug & DEBUG_SPLIT) {
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
*/
splitlock = lf_alloc(lock1->lf_uid, 0);
memcpy(splitlock, lock1, sizeof(*splitlock));
splitlock->lf_start = lock2->lf_end + 1;
splitlock->lf_block.tqe_next = NULL;
TAILQ_INIT(&splitlock->lf_blkhd);
lock1->lf_end = lock2->lf_start - 1;
/*
* OK, now link it in
*/
lock2->lf_next = splitlock;
lock1->lf_next = lock2;
}
/*
* Wakeup a blocklist
*/
void
lf_wakelock(struct lockf *lock)
{
struct lockf *wakelock;
while ((wakelock = TAILQ_FIRST(&lock->lf_blkhd))) {
TAILQ_REMOVE(&lock->lf_blkhd, wakelock, lf_block);
wakelock->lf_next = NULL;
wakeup_one(wakelock);
}
}
#ifdef LOCKF_DEBUG
/*
* Print out a lock.
*/
void
lf_print(char *tag, struct lockf *lock)
{
struct lockf *block;
printf("%s: lock %p for ", tag, lock);
if (lock->lf_flags & F_POSIX)
printf("proc %d", ((struct proc *)(lock->lf_id))->p_pid);
else
printf("id %p", lock->lf_id);
printf(" %s, start %llx, end %llx",
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);
block = TAILQ_FIRST(&lock->lf_blkhd);
if (block)
printf(" block");
TAILQ_FOREACH(block, &lock->lf_blkhd, lf_block)
printf(" %p,", block);
printf("\n");
}
void
lf_printlist(char *tag, struct lockf *lock)
{
struct lockf *lf;
printf("%s: Lock list:\n", tag);
for (lf = *lock->lf_head; lf; lf = lf->lf_next) {
printf("\tlock %p for ", lf);
if (lf->lf_flags & F_POSIX)
printf("proc %d", ((struct proc*)(lf->lf_id))->p_pid);
else
printf("id %p", lf->lf_id);
printf(" %s, start %llx, end %llx",
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);
printf("\n");
}
}
#endif /* LOCKF_DEBUG */