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 * 4. Neither the name of the University nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 *
32 * @(#)ufs_lockf.c 8.3 (Berkeley) 1/6/94
33 */
34
35#include <sys/cdefs.h>
| 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 * 4. Neither the name of the University nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 *
32 * @(#)ufs_lockf.c 8.3 (Berkeley) 1/6/94
33 */
34
35#include <sys/cdefs.h>
|
37
38#include "opt_debug_lockf.h"
39
40#include <sys/param.h>
41#include <sys/systm.h>
42#include <sys/kernel.h>
43#include <sys/limits.h>
44#include <sys/lock.h>
45#include <sys/mount.h>
46#include <sys/mutex.h>
47#include <sys/proc.h>
48#include <sys/unistd.h>
49#include <sys/vnode.h>
50#include <sys/malloc.h>
51#include <sys/fcntl.h>
52#include <sys/lockf.h>
53
54/*
55 * This variable controls the maximum number of processes that will
56 * be checked in doing deadlock detection.
57 */
58static int maxlockdepth = MAXDEPTH;
59
60#ifdef LOCKF_DEBUG
61#include <sys/sysctl.h>
62
63#include <ufs/ufs/quota.h>
64#include <ufs/ufs/inode.h>
65
66
67static int lockf_debug = 0;
68SYSCTL_INT(_debug, OID_AUTO, lockf_debug, CTLFLAG_RW, &lockf_debug, 0, "");
69#endif
70
71MALLOC_DEFINE(M_LOCKF, "lockf", "Byte-range locking structures");
72
73#define NOLOCKF (struct lockf *)0
74#define SELF 0x1
75#define OTHERS 0x2
76static int lf_clearlock(struct lockf *, struct lockf **);
77static int lf_findoverlap(struct lockf *,
78 struct lockf *, int, struct lockf ***, struct lockf **);
79static struct lockf *
80 lf_getblock(struct lockf *);
81static int lf_getlock(struct lockf *, struct flock *);
82static int lf_setlock(struct lockf *, struct vnode *, struct lockf **);
83static void lf_split(struct lockf *, struct lockf *, struct lockf **);
84static void lf_wakelock(struct lockf *);
85#ifdef LOCKF_DEBUG
86static void lf_print(char *, struct lockf *);
87static void lf_printlist(char *, struct lockf *);
88#endif
89
90/*
91 * Advisory record locking support
92 */
93int
94lf_advlock(ap, head, size)
95 struct vop_advlock_args /* {
96 struct vnode *a_vp;
97 caddr_t a_id;
98 int a_op;
99 struct flock *a_fl;
100 int a_flags;
101 } */ *ap;
102 struct lockf **head;
103 u_quad_t size;
104{
105 struct flock *fl = ap->a_fl;
106 struct lockf *lock;
107 struct vnode *vp = ap->a_vp;
108 off_t start, end, oadd;
109 struct lockf *clean, *n;
110 int error;
111
112 /*
113 * Convert the flock structure into a start and end.
114 */
115 switch (fl->l_whence) {
116
117 case SEEK_SET:
118 case SEEK_CUR:
119 /*
120 * Caller is responsible for adding any necessary offset
121 * when SEEK_CUR is used.
122 */
123 start = fl->l_start;
124 break;
125
126 case SEEK_END:
127 if (size > OFF_MAX ||
128 (fl->l_start > 0 && size > OFF_MAX - fl->l_start))
129 return (EOVERFLOW);
130 start = size + fl->l_start;
131 break;
132
133 default:
134 return (EINVAL);
135 }
136 if (start < 0)
137 return (EINVAL);
138 if (fl->l_len < 0) {
139 if (start == 0)
140 return (EINVAL);
141 end = start - 1;
142 start += fl->l_len;
143 if (start < 0)
144 return (EINVAL);
145 } else if (fl->l_len == 0)
146 end = -1;
147 else {
148 oadd = fl->l_len - 1;
149 if (oadd > OFF_MAX - start)
150 return (EOVERFLOW);
151 end = start + oadd;
152 }
153 /*
154 * Avoid the common case of unlocking when inode has no locks.
155 */
156 if (*head == (struct lockf *)0) {
157 if (ap->a_op != F_SETLK) {
158 fl->l_type = F_UNLCK;
159 return (0);
160 }
161 }
162 /*
163 * Allocate a spare structure in case we have to split.
164 */
165 clean = NULL;
166 if (ap->a_op == F_SETLK || ap->a_op == F_UNLCK) {
167 MALLOC(clean, struct lockf *, sizeof *lock, M_LOCKF, M_WAITOK);
168 clean->lf_next = NULL;
169 }
170 /*
171 * Create the lockf structure
172 */
173 MALLOC(lock, struct lockf *, sizeof *lock, M_LOCKF, M_WAITOK);
174 lock->lf_start = start;
175 lock->lf_end = end;
176 lock->lf_id = ap->a_id;
177 /*
178 * XXX The problem is that VTOI is ufs specific, so it will
179 * break LOCKF_DEBUG for all other FS's other than UFS because
180 * it casts the vnode->data ptr to struct inode *.
181 */
182/* lock->lf_inode = VTOI(ap->a_vp); */
183 lock->lf_inode = (struct inode *)0;
184 lock->lf_type = fl->l_type;
185 lock->lf_head = head;
186 lock->lf_next = (struct lockf *)0;
187 TAILQ_INIT(&lock->lf_blkhd);
188 lock->lf_flags = ap->a_flags;
189 /*
190 * Do the requested operation.
191 */
192 VI_LOCK(vp);
193 switch(ap->a_op) {
194 case F_SETLK:
195 error = lf_setlock(lock, vp, &clean);
196 break;
197
198 case F_UNLCK:
199 error = lf_clearlock(lock, &clean);
200 lock->lf_next = clean;
201 clean = lock;
202 break;
203
204 case F_GETLK:
205 error = lf_getlock(lock, fl);
206 lock->lf_next = clean;
207 clean = lock;
208 break;
209
210 default:
211 lock->lf_next = clean;
212 clean = lock;
213 error = EINVAL;
214 break;
215 }
216 VI_UNLOCK(vp);
217 for (lock = clean; lock != NULL; ) {
218 n = lock->lf_next;
219 free(lock, M_LOCKF);
220 lock = n;
221 }
222 return (error);
223}
224
225/*
226 * Set a byte-range lock.
227 */
228static int
229lf_setlock(lock, vp, clean)
230 struct lockf *lock;
231 struct vnode *vp;
232 struct lockf **clean;
233{
234 struct lockf *block;
235 struct lockf **head = lock->lf_head;
236 struct lockf **prev, *overlap, *ltmp;
237 static char lockstr[] = "lockf";
238 int ovcase, priority, needtolink, error;
239
240#ifdef LOCKF_DEBUG
241 if (lockf_debug & 1)
242 lf_print("lf_setlock", lock);
243#endif /* LOCKF_DEBUG */
244
245 /*
246 * Set the priority
247 */
248 priority = PLOCK;
249 if (lock->lf_type == F_WRLCK)
250 priority += 4;
251 priority |= PCATCH;
252 /*
253 * Scan lock list for this file looking for locks that would block us.
254 */
255 while ((block = lf_getblock(lock))) {
256 /*
257 * Free the structure and return if nonblocking.
258 */
259 if ((lock->lf_flags & F_WAIT) == 0) {
260 lock->lf_next = *clean;
261 *clean = lock;
262 return (EAGAIN);
263 }
264 /*
265 * We are blocked. Since flock style locks cover
266 * the whole file, there is no chance for deadlock.
267 * For byte-range locks we must check for deadlock.
268 *
269 * Deadlock detection is done by looking through the
270 * wait channels to see if there are any cycles that
271 * involve us. MAXDEPTH is set just to make sure we
272 * do not go off into neverland.
273 */
274 if ((lock->lf_flags & F_POSIX) &&
275 (block->lf_flags & F_POSIX)) {
276 struct proc *wproc;
277 struct proc *nproc;
278 struct thread *td;
279 struct lockf *waitblock;
280 int i = 0;
281
282 /* The block is waiting on something */
283 wproc = (struct proc *)block->lf_id;
284restart:
285 nproc = NULL;
| 37
38#include "opt_debug_lockf.h"
39
40#include <sys/param.h>
41#include <sys/systm.h>
42#include <sys/kernel.h>
43#include <sys/limits.h>
44#include <sys/lock.h>
45#include <sys/mount.h>
46#include <sys/mutex.h>
47#include <sys/proc.h>
48#include <sys/unistd.h>
49#include <sys/vnode.h>
50#include <sys/malloc.h>
51#include <sys/fcntl.h>
52#include <sys/lockf.h>
53
54/*
55 * This variable controls the maximum number of processes that will
56 * be checked in doing deadlock detection.
57 */
58static int maxlockdepth = MAXDEPTH;
59
60#ifdef LOCKF_DEBUG
61#include <sys/sysctl.h>
62
63#include <ufs/ufs/quota.h>
64#include <ufs/ufs/inode.h>
65
66
67static int lockf_debug = 0;
68SYSCTL_INT(_debug, OID_AUTO, lockf_debug, CTLFLAG_RW, &lockf_debug, 0, "");
69#endif
70
71MALLOC_DEFINE(M_LOCKF, "lockf", "Byte-range locking structures");
72
73#define NOLOCKF (struct lockf *)0
74#define SELF 0x1
75#define OTHERS 0x2
76static int lf_clearlock(struct lockf *, struct lockf **);
77static int lf_findoverlap(struct lockf *,
78 struct lockf *, int, struct lockf ***, struct lockf **);
79static struct lockf *
80 lf_getblock(struct lockf *);
81static int lf_getlock(struct lockf *, struct flock *);
82static int lf_setlock(struct lockf *, struct vnode *, struct lockf **);
83static void lf_split(struct lockf *, struct lockf *, struct lockf **);
84static void lf_wakelock(struct lockf *);
85#ifdef LOCKF_DEBUG
86static void lf_print(char *, struct lockf *);
87static void lf_printlist(char *, struct lockf *);
88#endif
89
90/*
91 * Advisory record locking support
92 */
93int
94lf_advlock(ap, head, size)
95 struct vop_advlock_args /* {
96 struct vnode *a_vp;
97 caddr_t a_id;
98 int a_op;
99 struct flock *a_fl;
100 int a_flags;
101 } */ *ap;
102 struct lockf **head;
103 u_quad_t size;
104{
105 struct flock *fl = ap->a_fl;
106 struct lockf *lock;
107 struct vnode *vp = ap->a_vp;
108 off_t start, end, oadd;
109 struct lockf *clean, *n;
110 int error;
111
112 /*
113 * Convert the flock structure into a start and end.
114 */
115 switch (fl->l_whence) {
116
117 case SEEK_SET:
118 case SEEK_CUR:
119 /*
120 * Caller is responsible for adding any necessary offset
121 * when SEEK_CUR is used.
122 */
123 start = fl->l_start;
124 break;
125
126 case SEEK_END:
127 if (size > OFF_MAX ||
128 (fl->l_start > 0 && size > OFF_MAX - fl->l_start))
129 return (EOVERFLOW);
130 start = size + fl->l_start;
131 break;
132
133 default:
134 return (EINVAL);
135 }
136 if (start < 0)
137 return (EINVAL);
138 if (fl->l_len < 0) {
139 if (start == 0)
140 return (EINVAL);
141 end = start - 1;
142 start += fl->l_len;
143 if (start < 0)
144 return (EINVAL);
145 } else if (fl->l_len == 0)
146 end = -1;
147 else {
148 oadd = fl->l_len - 1;
149 if (oadd > OFF_MAX - start)
150 return (EOVERFLOW);
151 end = start + oadd;
152 }
153 /*
154 * Avoid the common case of unlocking when inode has no locks.
155 */
156 if (*head == (struct lockf *)0) {
157 if (ap->a_op != F_SETLK) {
158 fl->l_type = F_UNLCK;
159 return (0);
160 }
161 }
162 /*
163 * Allocate a spare structure in case we have to split.
164 */
165 clean = NULL;
166 if (ap->a_op == F_SETLK || ap->a_op == F_UNLCK) {
167 MALLOC(clean, struct lockf *, sizeof *lock, M_LOCKF, M_WAITOK);
168 clean->lf_next = NULL;
169 }
170 /*
171 * Create the lockf structure
172 */
173 MALLOC(lock, struct lockf *, sizeof *lock, M_LOCKF, M_WAITOK);
174 lock->lf_start = start;
175 lock->lf_end = end;
176 lock->lf_id = ap->a_id;
177 /*
178 * XXX The problem is that VTOI is ufs specific, so it will
179 * break LOCKF_DEBUG for all other FS's other than UFS because
180 * it casts the vnode->data ptr to struct inode *.
181 */
182/* lock->lf_inode = VTOI(ap->a_vp); */
183 lock->lf_inode = (struct inode *)0;
184 lock->lf_type = fl->l_type;
185 lock->lf_head = head;
186 lock->lf_next = (struct lockf *)0;
187 TAILQ_INIT(&lock->lf_blkhd);
188 lock->lf_flags = ap->a_flags;
189 /*
190 * Do the requested operation.
191 */
192 VI_LOCK(vp);
193 switch(ap->a_op) {
194 case F_SETLK:
195 error = lf_setlock(lock, vp, &clean);
196 break;
197
198 case F_UNLCK:
199 error = lf_clearlock(lock, &clean);
200 lock->lf_next = clean;
201 clean = lock;
202 break;
203
204 case F_GETLK:
205 error = lf_getlock(lock, fl);
206 lock->lf_next = clean;
207 clean = lock;
208 break;
209
210 default:
211 lock->lf_next = clean;
212 clean = lock;
213 error = EINVAL;
214 break;
215 }
216 VI_UNLOCK(vp);
217 for (lock = clean; lock != NULL; ) {
218 n = lock->lf_next;
219 free(lock, M_LOCKF);
220 lock = n;
221 }
222 return (error);
223}
224
225/*
226 * Set a byte-range lock.
227 */
228static int
229lf_setlock(lock, vp, clean)
230 struct lockf *lock;
231 struct vnode *vp;
232 struct lockf **clean;
233{
234 struct lockf *block;
235 struct lockf **head = lock->lf_head;
236 struct lockf **prev, *overlap, *ltmp;
237 static char lockstr[] = "lockf";
238 int ovcase, priority, needtolink, error;
239
240#ifdef LOCKF_DEBUG
241 if (lockf_debug & 1)
242 lf_print("lf_setlock", lock);
243#endif /* LOCKF_DEBUG */
244
245 /*
246 * Set the priority
247 */
248 priority = PLOCK;
249 if (lock->lf_type == F_WRLCK)
250 priority += 4;
251 priority |= PCATCH;
252 /*
253 * Scan lock list for this file looking for locks that would block us.
254 */
255 while ((block = lf_getblock(lock))) {
256 /*
257 * Free the structure and return if nonblocking.
258 */
259 if ((lock->lf_flags & F_WAIT) == 0) {
260 lock->lf_next = *clean;
261 *clean = lock;
262 return (EAGAIN);
263 }
264 /*
265 * We are blocked. Since flock style locks cover
266 * the whole file, there is no chance for deadlock.
267 * For byte-range locks we must check for deadlock.
268 *
269 * Deadlock detection is done by looking through the
270 * wait channels to see if there are any cycles that
271 * involve us. MAXDEPTH is set just to make sure we
272 * do not go off into neverland.
273 */
274 if ((lock->lf_flags & F_POSIX) &&
275 (block->lf_flags & F_POSIX)) {
276 struct proc *wproc;
277 struct proc *nproc;
278 struct thread *td;
279 struct lockf *waitblock;
280 int i = 0;
281
282 /* The block is waiting on something */
283 wproc = (struct proc *)block->lf_id;
284restart:
285 nproc = NULL;
|
309 wproc = nproc;
310 if (wproc)
311 goto restart;
312 }
313 /*
314 * For flock type locks, we must first remove
315 * any shared locks that we hold before we sleep
316 * waiting for an exclusive lock.
317 */
318 if ((lock->lf_flags & F_FLOCK) &&
319 lock->lf_type == F_WRLCK) {
320 lock->lf_type = F_UNLCK;
321 (void) lf_clearlock(lock, clean);
322 lock->lf_type = F_WRLCK;
323 }
324 /*
325 * Add our lock to the blocked list and sleep until we're free.
326 * Remember who blocked us (for deadlock detection).
327 */
328 lock->lf_next = block;
329 TAILQ_INSERT_TAIL(&block->lf_blkhd, lock, lf_block);
330#ifdef LOCKF_DEBUG
331 if (lockf_debug & 1) {
332 lf_print("lf_setlock: blocking on", block);
333 lf_printlist("lf_setlock", block);
334 }
335#endif /* LOCKF_DEBUG */
336 error = msleep(lock, VI_MTX(vp), priority, lockstr, 0);
337 /*
338 * We may have been awakened by a signal and/or by a
339 * debugger continuing us (in which cases we must remove
340 * ourselves from the blocked list) and/or by another
341 * process releasing a lock (in which case we have
342 * already been removed from the blocked list and our
343 * lf_next field set to NOLOCKF).
344 */
345 if (lock->lf_next) {
346 TAILQ_REMOVE(&lock->lf_next->lf_blkhd, lock, lf_block);
347 lock->lf_next = NOLOCKF;
348 }
349 if (error) {
350 lock->lf_next = *clean;
351 *clean = lock;
352 return (error);
353 }
354 }
355 /*
356 * No blocks!! Add the lock. Note that we will
357 * downgrade or upgrade any overlapping locks this
358 * process already owns.
359 *
360 * Skip over locks owned by other processes.
361 * Handle any locks that overlap and are owned by ourselves.
362 */
363 prev = head;
364 block = *head;
365 needtolink = 1;
366 for (;;) {
367 ovcase = lf_findoverlap(block, lock, SELF, &prev, &overlap);
368 if (ovcase)
369 block = overlap->lf_next;
370 /*
371 * Six cases:
372 * 0) no overlap
373 * 1) overlap == lock
374 * 2) overlap contains lock
375 * 3) lock contains overlap
376 * 4) overlap starts before lock
377 * 5) overlap ends after lock
378 */
379 switch (ovcase) {
380 case 0: /* no overlap */
381 if (needtolink) {
382 *prev = lock;
383 lock->lf_next = overlap;
384 }
385 break;
386
387 case 1: /* overlap == lock */
388 /*
389 * If downgrading lock, others may be
390 * able to acquire it.
391 */
392 if (lock->lf_type == F_RDLCK &&
393 overlap->lf_type == F_WRLCK)
394 lf_wakelock(overlap);
395 overlap->lf_type = lock->lf_type;
396 lock->lf_next = *clean;
397 *clean = lock;
398 lock = overlap; /* for debug output below */
399 break;
400
401 case 2: /* overlap contains lock */
402 /*
403 * Check for common starting point and different types.
404 */
405 if (overlap->lf_type == lock->lf_type) {
406 lock->lf_next = *clean;
407 *clean = lock;
408 lock = overlap; /* for debug output below */
409 break;
410 }
411 if (overlap->lf_start == lock->lf_start) {
412 *prev = lock;
413 lock->lf_next = overlap;
414 overlap->lf_start = lock->lf_end + 1;
415 } else
416 lf_split(overlap, lock, clean);
417 lf_wakelock(overlap);
418 break;
419
420 case 3: /* lock contains overlap */
421 /*
422 * If downgrading lock, others may be able to
423 * acquire it, otherwise take the list.
424 */
425 if (lock->lf_type == F_RDLCK &&
426 overlap->lf_type == F_WRLCK) {
427 lf_wakelock(overlap);
428 } else {
429 while (!TAILQ_EMPTY(&overlap->lf_blkhd)) {
430 ltmp = TAILQ_FIRST(&overlap->lf_blkhd);
431 TAILQ_REMOVE(&overlap->lf_blkhd, ltmp,
432 lf_block);
433 TAILQ_INSERT_TAIL(&lock->lf_blkhd,
434 ltmp, lf_block);
435 ltmp->lf_next = lock;
436 }
437 }
438 /*
439 * Add the new lock if necessary and delete the overlap.
440 */
441 if (needtolink) {
442 *prev = lock;
443 lock->lf_next = overlap->lf_next;
444 prev = &lock->lf_next;
445 needtolink = 0;
446 } else
447 *prev = overlap->lf_next;
448 overlap->lf_next = *clean;
449 *clean = overlap;
450 continue;
451
452 case 4: /* overlap starts before lock */
453 /*
454 * Add lock after overlap on the list.
455 */
456 lock->lf_next = overlap->lf_next;
457 overlap->lf_next = lock;
458 overlap->lf_end = lock->lf_start - 1;
459 prev = &lock->lf_next;
460 lf_wakelock(overlap);
461 needtolink = 0;
462 continue;
463
464 case 5: /* overlap ends after lock */
465 /*
466 * Add the new lock before overlap.
467 */
468 if (needtolink) {
469 *prev = lock;
470 lock->lf_next = overlap;
471 }
472 overlap->lf_start = lock->lf_end + 1;
473 lf_wakelock(overlap);
474 break;
475 }
476 break;
477 }
478#ifdef LOCKF_DEBUG
479 if (lockf_debug & 1) {
480 lf_print("lf_setlock: got the lock", lock);
481 lf_printlist("lf_setlock", lock);
482 }
483#endif /* LOCKF_DEBUG */
484 return (0);
485}
486
487/*
488 * Remove a byte-range lock on an inode.
489 *
490 * Generally, find the lock (or an overlap to that lock)
491 * and remove it (or shrink it), then wakeup anyone we can.
492 */
493static int
494lf_clearlock(unlock, clean)
495 struct lockf *unlock;
496 struct lockf **clean;
497{
498 struct lockf **head = unlock->lf_head;
499 register struct lockf *lf = *head;
500 struct lockf *overlap, **prev;
501 int ovcase;
502
503 if (lf == NOLOCKF)
504 return (0);
505#ifdef LOCKF_DEBUG
506 if (unlock->lf_type != F_UNLCK)
507 panic("lf_clearlock: bad type");
508 if (lockf_debug & 1)
509 lf_print("lf_clearlock", unlock);
510#endif /* LOCKF_DEBUG */
511 prev = head;
512 while ((ovcase = lf_findoverlap(lf, unlock, SELF, &prev, &overlap))) {
513 /*
514 * Wakeup the list of locks to be retried.
515 */
516 lf_wakelock(overlap);
517
518 switch (ovcase) {
519
520 case 1: /* overlap == lock */
521 *prev = overlap->lf_next;
522 overlap->lf_next = *clean;
523 *clean = overlap;
524 break;
525
526 case 2: /* overlap contains lock: split it */
527 if (overlap->lf_start == unlock->lf_start) {
528 overlap->lf_start = unlock->lf_end + 1;
529 break;
530 }
531 lf_split(overlap, unlock, clean);
532 overlap->lf_next = unlock->lf_next;
533 break;
534
535 case 3: /* lock contains overlap */
536 *prev = overlap->lf_next;
537 lf = overlap->lf_next;
538 overlap->lf_next = *clean;
539 *clean = overlap;
540 continue;
541
542 case 4: /* overlap starts before lock */
543 overlap->lf_end = unlock->lf_start - 1;
544 prev = &overlap->lf_next;
545 lf = overlap->lf_next;
546 continue;
547
548 case 5: /* overlap ends after lock */
549 overlap->lf_start = unlock->lf_end + 1;
550 break;
551 }
552 break;
553 }
554#ifdef LOCKF_DEBUG
555 if (lockf_debug & 1)
556 lf_printlist("lf_clearlock", unlock);
557#endif /* LOCKF_DEBUG */
558 return (0);
559}
560
561/*
562 * Check whether there is a blocking lock,
563 * and if so return its process identifier.
564 */
565static int
566lf_getlock(lock, fl)
567 register struct lockf *lock;
568 register struct flock *fl;
569{
570 register struct lockf *block;
571
572#ifdef LOCKF_DEBUG
573 if (lockf_debug & 1)
574 lf_print("lf_getlock", lock);
575#endif /* LOCKF_DEBUG */
576
577 if ((block = lf_getblock(lock))) {
578 fl->l_type = block->lf_type;
579 fl->l_whence = SEEK_SET;
580 fl->l_start = block->lf_start;
581 if (block->lf_end == -1)
582 fl->l_len = 0;
583 else
584 fl->l_len = block->lf_end - block->lf_start + 1;
585 if (block->lf_flags & F_POSIX)
586 fl->l_pid = ((struct proc *)(block->lf_id))->p_pid;
587 else
588 fl->l_pid = -1;
589 } else {
590 fl->l_type = F_UNLCK;
591 }
592 return (0);
593}
594
595/*
596 * Walk the list of locks for an inode and
597 * return the first blocking lock.
598 */
599static struct lockf *
600lf_getblock(lock)
601 register struct lockf *lock;
602{
603 struct lockf **prev, *overlap, *lf = *(lock->lf_head);
604 int ovcase;
605
606 prev = lock->lf_head;
607 while ((ovcase = lf_findoverlap(lf, lock, OTHERS, &prev, &overlap))) {
608 /*
609 * We've found an overlap, see if it blocks us
610 */
611 if ((lock->lf_type == F_WRLCK || overlap->lf_type == F_WRLCK))
612 return (overlap);
613 /*
614 * Nope, point to the next one on the list and
615 * see if it blocks us
616 */
617 lf = overlap->lf_next;
618 }
619 return (NOLOCKF);
620}
621
622/*
623 * Walk the list of locks for an inode to
624 * find an overlapping lock (if any).
625 *
626 * NOTE: this returns only the FIRST overlapping lock. There
627 * may be more than one.
628 */
629static int
630lf_findoverlap(lf, lock, type, prev, overlap)
631 register struct lockf *lf;
632 struct lockf *lock;
633 int type;
634 struct lockf ***prev;
635 struct lockf **overlap;
636{
637 off_t start, end;
638
639 *overlap = lf;
640 if (lf == NOLOCKF)
641 return (0);
642#ifdef LOCKF_DEBUG
643 if (lockf_debug & 2)
644 lf_print("lf_findoverlap: looking for overlap in", lock);
645#endif /* LOCKF_DEBUG */
646 start = lock->lf_start;
647 end = lock->lf_end;
648 while (lf != NOLOCKF) {
649 if (((type & SELF) && lf->lf_id != lock->lf_id) ||
650 ((type & OTHERS) && lf->lf_id == lock->lf_id)) {
651 *prev = &lf->lf_next;
652 *overlap = lf = lf->lf_next;
653 continue;
654 }
655#ifdef LOCKF_DEBUG
656 if (lockf_debug & 2)
657 lf_print("\tchecking", lf);
658#endif /* LOCKF_DEBUG */
659 /*
660 * OK, check for overlap
661 *
662 * Six cases:
663 * 0) no overlap
664 * 1) overlap == lock
665 * 2) overlap contains lock
666 * 3) lock contains overlap
667 * 4) overlap starts before lock
668 * 5) overlap ends after lock
669 */
670 if ((lf->lf_end != -1 && start > lf->lf_end) ||
671 (end != -1 && lf->lf_start > end)) {
672 /* Case 0 */
673#ifdef LOCKF_DEBUG
674 if (lockf_debug & 2)
675 printf("no overlap\n");
676#endif /* LOCKF_DEBUG */
677 if ((type & SELF) && end != -1 && lf->lf_start > end)
678 return (0);
679 *prev = &lf->lf_next;
680 *overlap = lf = lf->lf_next;
681 continue;
682 }
683 if ((lf->lf_start == start) && (lf->lf_end == end)) {
684 /* Case 1 */
685#ifdef LOCKF_DEBUG
686 if (lockf_debug & 2)
687 printf("overlap == lock\n");
688#endif /* LOCKF_DEBUG */
689 return (1);
690 }
691 if ((lf->lf_start <= start) &&
692 (end != -1) &&
693 ((lf->lf_end >= end) || (lf->lf_end == -1))) {
694 /* Case 2 */
695#ifdef LOCKF_DEBUG
696 if (lockf_debug & 2)
697 printf("overlap contains lock\n");
698#endif /* LOCKF_DEBUG */
699 return (2);
700 }
701 if (start <= lf->lf_start &&
702 (end == -1 ||
703 (lf->lf_end != -1 && end >= lf->lf_end))) {
704 /* Case 3 */
705#ifdef LOCKF_DEBUG
706 if (lockf_debug & 2)
707 printf("lock contains overlap\n");
708#endif /* LOCKF_DEBUG */
709 return (3);
710 }
711 if ((lf->lf_start < start) &&
712 ((lf->lf_end >= start) || (lf->lf_end == -1))) {
713 /* Case 4 */
714#ifdef LOCKF_DEBUG
715 if (lockf_debug & 2)
716 printf("overlap starts before lock\n");
717#endif /* LOCKF_DEBUG */
718 return (4);
719 }
720 if ((lf->lf_start > start) &&
721 (end != -1) &&
722 ((lf->lf_end > end) || (lf->lf_end == -1))) {
723 /* Case 5 */
724#ifdef LOCKF_DEBUG
725 if (lockf_debug & 2)
726 printf("overlap ends after lock\n");
727#endif /* LOCKF_DEBUG */
728 return (5);
729 }
730 panic("lf_findoverlap: default");
731 }
732 return (0);
733}
734
735/*
736 * Split a lock and a contained region into
737 * two or three locks as necessary.
738 */
739static void
740lf_split(lock1, lock2, split)
741 struct lockf *lock1;
742 struct lockf *lock2;
743 struct lockf **split;
744{
745 struct lockf *splitlock;
746
747#ifdef LOCKF_DEBUG
748 if (lockf_debug & 2) {
749 lf_print("lf_split", lock1);
750 lf_print("splitting from", lock2);
751 }
752#endif /* LOCKF_DEBUG */
753 /*
754 * Check to see if spliting into only two pieces.
755 */
756 if (lock1->lf_start == lock2->lf_start) {
757 lock1->lf_start = lock2->lf_end + 1;
758 lock2->lf_next = lock1;
759 return;
760 }
761 if (lock1->lf_end == lock2->lf_end) {
762 lock1->lf_end = lock2->lf_start - 1;
763 lock2->lf_next = lock1->lf_next;
764 lock1->lf_next = lock2;
765 return;
766 }
767 /*
768 * Make a new lock consisting of the last part of
769 * the encompassing lock. We use the preallocated
770 * splitlock so we don't have to block.
771 */
772 splitlock = *split;
773 KASSERT(splitlock != NULL, ("no split"));
774 *split = splitlock->lf_next;
775 bcopy(lock1, splitlock, sizeof *splitlock);
776 splitlock->lf_start = lock2->lf_end + 1;
777 TAILQ_INIT(&splitlock->lf_blkhd);
778 lock1->lf_end = lock2->lf_start - 1;
779 /*
780 * OK, now link it in
781 */
782 splitlock->lf_next = lock1->lf_next;
783 lock2->lf_next = splitlock;
784 lock1->lf_next = lock2;
785}
786
787/*
788 * Wakeup a blocklist
789 */
790static void
791lf_wakelock(listhead)
792 struct lockf *listhead;
793{
794 register struct lockf *wakelock;
795
796 while (!TAILQ_EMPTY(&listhead->lf_blkhd)) {
797 wakelock = TAILQ_FIRST(&listhead->lf_blkhd);
798 TAILQ_REMOVE(&listhead->lf_blkhd, wakelock, lf_block);
799 wakelock->lf_next = NOLOCKF;
800#ifdef LOCKF_DEBUG
801 if (lockf_debug & 2)
802 lf_print("lf_wakelock: awakening", wakelock);
803#endif /* LOCKF_DEBUG */
804 wakeup(wakelock);
805 }
806}
807
808#ifdef LOCKF_DEBUG
809/*
810 * Print out a lock.
811 */
812static void
813lf_print(tag, lock)
814 char *tag;
815 register struct lockf *lock;
816{
817
818 printf("%s: lock %p for ", tag, (void *)lock);
819 if (lock->lf_flags & F_POSIX)
820 printf("proc %ld", (long)((struct proc *)lock->lf_id)->p_pid);
821 else
822 printf("id %p", (void *)lock->lf_id);
823 if (lock->lf_inode != (struct inode *)0)
824 printf(" in ino %ju on dev <%s>, %s, start %jd, end %jd",
825 (uintmax_t)lock->lf_inode->i_number,
826 devtoname(lock->lf_inode->i_dev),
827 lock->lf_type == F_RDLCK ? "shared" :
828 lock->lf_type == F_WRLCK ? "exclusive" :
829 lock->lf_type == F_UNLCK ? "unlock" : "unknown",
830 (intmax_t)lock->lf_start, (intmax_t)lock->lf_end);
831 else
832 printf(" %s, start %jd, end %jd",
833 lock->lf_type == F_RDLCK ? "shared" :
834 lock->lf_type == F_WRLCK ? "exclusive" :
835 lock->lf_type == F_UNLCK ? "unlock" : "unknown",
836 (intmax_t)lock->lf_start, (intmax_t)lock->lf_end);
837 if (!TAILQ_EMPTY(&lock->lf_blkhd))
838 printf(" block %p\n", (void *)TAILQ_FIRST(&lock->lf_blkhd));
839 else
840 printf("\n");
841}
842
843static void
844lf_printlist(tag, lock)
845 char *tag;
846 struct lockf *lock;
847{
848 register struct lockf *lf, *blk;
849
850 if (lock->lf_inode == (struct inode *)0)
851 return;
852
853 printf("%s: Lock list for ino %ju on dev <%s>:\n",
854 tag, (uintmax_t)lock->lf_inode->i_number,
855 devtoname(lock->lf_inode->i_dev));
856 for (lf = lock->lf_inode->i_lockf; lf; lf = lf->lf_next) {
857 printf("\tlock %p for ",(void *)lf);
858 if (lf->lf_flags & F_POSIX)
859 printf("proc %ld",
860 (long)((struct proc *)lf->lf_id)->p_pid);
861 else
862 printf("id %p", (void *)lf->lf_id);
863 printf(", %s, start %jd, end %jd",
864 lf->lf_type == F_RDLCK ? "shared" :
865 lf->lf_type == F_WRLCK ? "exclusive" :
866 lf->lf_type == F_UNLCK ? "unlock" :
867 "unknown", (intmax_t)lf->lf_start, (intmax_t)lf->lf_end);
868 TAILQ_FOREACH(blk, &lf->lf_blkhd, lf_block) {
869 printf("\n\t\tlock request %p for ", (void *)blk);
870 if (blk->lf_flags & F_POSIX)
871 printf("proc %ld",
872 (long)((struct proc *)blk->lf_id)->p_pid);
873 else
874 printf("id %p", (void *)blk->lf_id);
875 printf(", %s, start %jd, end %jd",
876 blk->lf_type == F_RDLCK ? "shared" :
877 blk->lf_type == F_WRLCK ? "exclusive" :
878 blk->lf_type == F_UNLCK ? "unlock" :
879 "unknown", (intmax_t)blk->lf_start,
880 (intmax_t)blk->lf_end);
881 if (!TAILQ_EMPTY(&blk->lf_blkhd))
882 panic("lf_printlist: bad list");
883 }
884 printf("\n");
885 }
886}
887#endif /* LOCKF_DEBUG */
| 309 wproc = nproc;
310 if (wproc)
311 goto restart;
312 }
313 /*
314 * For flock type locks, we must first remove
315 * any shared locks that we hold before we sleep
316 * waiting for an exclusive lock.
317 */
318 if ((lock->lf_flags & F_FLOCK) &&
319 lock->lf_type == F_WRLCK) {
320 lock->lf_type = F_UNLCK;
321 (void) lf_clearlock(lock, clean);
322 lock->lf_type = F_WRLCK;
323 }
324 /*
325 * Add our lock to the blocked list and sleep until we're free.
326 * Remember who blocked us (for deadlock detection).
327 */
328 lock->lf_next = block;
329 TAILQ_INSERT_TAIL(&block->lf_blkhd, lock, lf_block);
330#ifdef LOCKF_DEBUG
331 if (lockf_debug & 1) {
332 lf_print("lf_setlock: blocking on", block);
333 lf_printlist("lf_setlock", block);
334 }
335#endif /* LOCKF_DEBUG */
336 error = msleep(lock, VI_MTX(vp), priority, lockstr, 0);
337 /*
338 * We may have been awakened by a signal and/or by a
339 * debugger continuing us (in which cases we must remove
340 * ourselves from the blocked list) and/or by another
341 * process releasing a lock (in which case we have
342 * already been removed from the blocked list and our
343 * lf_next field set to NOLOCKF).
344 */
345 if (lock->lf_next) {
346 TAILQ_REMOVE(&lock->lf_next->lf_blkhd, lock, lf_block);
347 lock->lf_next = NOLOCKF;
348 }
349 if (error) {
350 lock->lf_next = *clean;
351 *clean = lock;
352 return (error);
353 }
354 }
355 /*
356 * No blocks!! Add the lock. Note that we will
357 * downgrade or upgrade any overlapping locks this
358 * process already owns.
359 *
360 * Skip over locks owned by other processes.
361 * Handle any locks that overlap and are owned by ourselves.
362 */
363 prev = head;
364 block = *head;
365 needtolink = 1;
366 for (;;) {
367 ovcase = lf_findoverlap(block, lock, SELF, &prev, &overlap);
368 if (ovcase)
369 block = overlap->lf_next;
370 /*
371 * Six cases:
372 * 0) no overlap
373 * 1) overlap == lock
374 * 2) overlap contains lock
375 * 3) lock contains overlap
376 * 4) overlap starts before lock
377 * 5) overlap ends after lock
378 */
379 switch (ovcase) {
380 case 0: /* no overlap */
381 if (needtolink) {
382 *prev = lock;
383 lock->lf_next = overlap;
384 }
385 break;
386
387 case 1: /* overlap == lock */
388 /*
389 * If downgrading lock, others may be
390 * able to acquire it.
391 */
392 if (lock->lf_type == F_RDLCK &&
393 overlap->lf_type == F_WRLCK)
394 lf_wakelock(overlap);
395 overlap->lf_type = lock->lf_type;
396 lock->lf_next = *clean;
397 *clean = lock;
398 lock = overlap; /* for debug output below */
399 break;
400
401 case 2: /* overlap contains lock */
402 /*
403 * Check for common starting point and different types.
404 */
405 if (overlap->lf_type == lock->lf_type) {
406 lock->lf_next = *clean;
407 *clean = lock;
408 lock = overlap; /* for debug output below */
409 break;
410 }
411 if (overlap->lf_start == lock->lf_start) {
412 *prev = lock;
413 lock->lf_next = overlap;
414 overlap->lf_start = lock->lf_end + 1;
415 } else
416 lf_split(overlap, lock, clean);
417 lf_wakelock(overlap);
418 break;
419
420 case 3: /* lock contains overlap */
421 /*
422 * If downgrading lock, others may be able to
423 * acquire it, otherwise take the list.
424 */
425 if (lock->lf_type == F_RDLCK &&
426 overlap->lf_type == F_WRLCK) {
427 lf_wakelock(overlap);
428 } else {
429 while (!TAILQ_EMPTY(&overlap->lf_blkhd)) {
430 ltmp = TAILQ_FIRST(&overlap->lf_blkhd);
431 TAILQ_REMOVE(&overlap->lf_blkhd, ltmp,
432 lf_block);
433 TAILQ_INSERT_TAIL(&lock->lf_blkhd,
434 ltmp, lf_block);
435 ltmp->lf_next = lock;
436 }
437 }
438 /*
439 * Add the new lock if necessary and delete the overlap.
440 */
441 if (needtolink) {
442 *prev = lock;
443 lock->lf_next = overlap->lf_next;
444 prev = &lock->lf_next;
445 needtolink = 0;
446 } else
447 *prev = overlap->lf_next;
448 overlap->lf_next = *clean;
449 *clean = overlap;
450 continue;
451
452 case 4: /* overlap starts before lock */
453 /*
454 * Add lock after overlap on the list.
455 */
456 lock->lf_next = overlap->lf_next;
457 overlap->lf_next = lock;
458 overlap->lf_end = lock->lf_start - 1;
459 prev = &lock->lf_next;
460 lf_wakelock(overlap);
461 needtolink = 0;
462 continue;
463
464 case 5: /* overlap ends after lock */
465 /*
466 * Add the new lock before overlap.
467 */
468 if (needtolink) {
469 *prev = lock;
470 lock->lf_next = overlap;
471 }
472 overlap->lf_start = lock->lf_end + 1;
473 lf_wakelock(overlap);
474 break;
475 }
476 break;
477 }
478#ifdef LOCKF_DEBUG
479 if (lockf_debug & 1) {
480 lf_print("lf_setlock: got the lock", lock);
481 lf_printlist("lf_setlock", lock);
482 }
483#endif /* LOCKF_DEBUG */
484 return (0);
485}
486
487/*
488 * Remove a byte-range lock on an inode.
489 *
490 * Generally, find the lock (or an overlap to that lock)
491 * and remove it (or shrink it), then wakeup anyone we can.
492 */
493static int
494lf_clearlock(unlock, clean)
495 struct lockf *unlock;
496 struct lockf **clean;
497{
498 struct lockf **head = unlock->lf_head;
499 register struct lockf *lf = *head;
500 struct lockf *overlap, **prev;
501 int ovcase;
502
503 if (lf == NOLOCKF)
504 return (0);
505#ifdef LOCKF_DEBUG
506 if (unlock->lf_type != F_UNLCK)
507 panic("lf_clearlock: bad type");
508 if (lockf_debug & 1)
509 lf_print("lf_clearlock", unlock);
510#endif /* LOCKF_DEBUG */
511 prev = head;
512 while ((ovcase = lf_findoverlap(lf, unlock, SELF, &prev, &overlap))) {
513 /*
514 * Wakeup the list of locks to be retried.
515 */
516 lf_wakelock(overlap);
517
518 switch (ovcase) {
519
520 case 1: /* overlap == lock */
521 *prev = overlap->lf_next;
522 overlap->lf_next = *clean;
523 *clean = overlap;
524 break;
525
526 case 2: /* overlap contains lock: split it */
527 if (overlap->lf_start == unlock->lf_start) {
528 overlap->lf_start = unlock->lf_end + 1;
529 break;
530 }
531 lf_split(overlap, unlock, clean);
532 overlap->lf_next = unlock->lf_next;
533 break;
534
535 case 3: /* lock contains overlap */
536 *prev = overlap->lf_next;
537 lf = overlap->lf_next;
538 overlap->lf_next = *clean;
539 *clean = overlap;
540 continue;
541
542 case 4: /* overlap starts before lock */
543 overlap->lf_end = unlock->lf_start - 1;
544 prev = &overlap->lf_next;
545 lf = overlap->lf_next;
546 continue;
547
548 case 5: /* overlap ends after lock */
549 overlap->lf_start = unlock->lf_end + 1;
550 break;
551 }
552 break;
553 }
554#ifdef LOCKF_DEBUG
555 if (lockf_debug & 1)
556 lf_printlist("lf_clearlock", unlock);
557#endif /* LOCKF_DEBUG */
558 return (0);
559}
560
561/*
562 * Check whether there is a blocking lock,
563 * and if so return its process identifier.
564 */
565static int
566lf_getlock(lock, fl)
567 register struct lockf *lock;
568 register struct flock *fl;
569{
570 register struct lockf *block;
571
572#ifdef LOCKF_DEBUG
573 if (lockf_debug & 1)
574 lf_print("lf_getlock", lock);
575#endif /* LOCKF_DEBUG */
576
577 if ((block = lf_getblock(lock))) {
578 fl->l_type = block->lf_type;
579 fl->l_whence = SEEK_SET;
580 fl->l_start = block->lf_start;
581 if (block->lf_end == -1)
582 fl->l_len = 0;
583 else
584 fl->l_len = block->lf_end - block->lf_start + 1;
585 if (block->lf_flags & F_POSIX)
586 fl->l_pid = ((struct proc *)(block->lf_id))->p_pid;
587 else
588 fl->l_pid = -1;
589 } else {
590 fl->l_type = F_UNLCK;
591 }
592 return (0);
593}
594
595/*
596 * Walk the list of locks for an inode and
597 * return the first blocking lock.
598 */
599static struct lockf *
600lf_getblock(lock)
601 register struct lockf *lock;
602{
603 struct lockf **prev, *overlap, *lf = *(lock->lf_head);
604 int ovcase;
605
606 prev = lock->lf_head;
607 while ((ovcase = lf_findoverlap(lf, lock, OTHERS, &prev, &overlap))) {
608 /*
609 * We've found an overlap, see if it blocks us
610 */
611 if ((lock->lf_type == F_WRLCK || overlap->lf_type == F_WRLCK))
612 return (overlap);
613 /*
614 * Nope, point to the next one on the list and
615 * see if it blocks us
616 */
617 lf = overlap->lf_next;
618 }
619 return (NOLOCKF);
620}
621
622/*
623 * Walk the list of locks for an inode to
624 * find an overlapping lock (if any).
625 *
626 * NOTE: this returns only the FIRST overlapping lock. There
627 * may be more than one.
628 */
629static int
630lf_findoverlap(lf, lock, type, prev, overlap)
631 register struct lockf *lf;
632 struct lockf *lock;
633 int type;
634 struct lockf ***prev;
635 struct lockf **overlap;
636{
637 off_t start, end;
638
639 *overlap = lf;
640 if (lf == NOLOCKF)
641 return (0);
642#ifdef LOCKF_DEBUG
643 if (lockf_debug & 2)
644 lf_print("lf_findoverlap: looking for overlap in", lock);
645#endif /* LOCKF_DEBUG */
646 start = lock->lf_start;
647 end = lock->lf_end;
648 while (lf != NOLOCKF) {
649 if (((type & SELF) && lf->lf_id != lock->lf_id) ||
650 ((type & OTHERS) && lf->lf_id == lock->lf_id)) {
651 *prev = &lf->lf_next;
652 *overlap = lf = lf->lf_next;
653 continue;
654 }
655#ifdef LOCKF_DEBUG
656 if (lockf_debug & 2)
657 lf_print("\tchecking", lf);
658#endif /* LOCKF_DEBUG */
659 /*
660 * OK, check for overlap
661 *
662 * Six cases:
663 * 0) no overlap
664 * 1) overlap == lock
665 * 2) overlap contains lock
666 * 3) lock contains overlap
667 * 4) overlap starts before lock
668 * 5) overlap ends after lock
669 */
670 if ((lf->lf_end != -1 && start > lf->lf_end) ||
671 (end != -1 && lf->lf_start > end)) {
672 /* Case 0 */
673#ifdef LOCKF_DEBUG
674 if (lockf_debug & 2)
675 printf("no overlap\n");
676#endif /* LOCKF_DEBUG */
677 if ((type & SELF) && end != -1 && lf->lf_start > end)
678 return (0);
679 *prev = &lf->lf_next;
680 *overlap = lf = lf->lf_next;
681 continue;
682 }
683 if ((lf->lf_start == start) && (lf->lf_end == end)) {
684 /* Case 1 */
685#ifdef LOCKF_DEBUG
686 if (lockf_debug & 2)
687 printf("overlap == lock\n");
688#endif /* LOCKF_DEBUG */
689 return (1);
690 }
691 if ((lf->lf_start <= start) &&
692 (end != -1) &&
693 ((lf->lf_end >= end) || (lf->lf_end == -1))) {
694 /* Case 2 */
695#ifdef LOCKF_DEBUG
696 if (lockf_debug & 2)
697 printf("overlap contains lock\n");
698#endif /* LOCKF_DEBUG */
699 return (2);
700 }
701 if (start <= lf->lf_start &&
702 (end == -1 ||
703 (lf->lf_end != -1 && end >= lf->lf_end))) {
704 /* Case 3 */
705#ifdef LOCKF_DEBUG
706 if (lockf_debug & 2)
707 printf("lock contains overlap\n");
708#endif /* LOCKF_DEBUG */
709 return (3);
710 }
711 if ((lf->lf_start < start) &&
712 ((lf->lf_end >= start) || (lf->lf_end == -1))) {
713 /* Case 4 */
714#ifdef LOCKF_DEBUG
715 if (lockf_debug & 2)
716 printf("overlap starts before lock\n");
717#endif /* LOCKF_DEBUG */
718 return (4);
719 }
720 if ((lf->lf_start > start) &&
721 (end != -1) &&
722 ((lf->lf_end > end) || (lf->lf_end == -1))) {
723 /* Case 5 */
724#ifdef LOCKF_DEBUG
725 if (lockf_debug & 2)
726 printf("overlap ends after lock\n");
727#endif /* LOCKF_DEBUG */
728 return (5);
729 }
730 panic("lf_findoverlap: default");
731 }
732 return (0);
733}
734
735/*
736 * Split a lock and a contained region into
737 * two or three locks as necessary.
738 */
739static void
740lf_split(lock1, lock2, split)
741 struct lockf *lock1;
742 struct lockf *lock2;
743 struct lockf **split;
744{
745 struct lockf *splitlock;
746
747#ifdef LOCKF_DEBUG
748 if (lockf_debug & 2) {
749 lf_print("lf_split", lock1);
750 lf_print("splitting from", lock2);
751 }
752#endif /* LOCKF_DEBUG */
753 /*
754 * Check to see if spliting into only two pieces.
755 */
756 if (lock1->lf_start == lock2->lf_start) {
757 lock1->lf_start = lock2->lf_end + 1;
758 lock2->lf_next = lock1;
759 return;
760 }
761 if (lock1->lf_end == lock2->lf_end) {
762 lock1->lf_end = lock2->lf_start - 1;
763 lock2->lf_next = lock1->lf_next;
764 lock1->lf_next = lock2;
765 return;
766 }
767 /*
768 * Make a new lock consisting of the last part of
769 * the encompassing lock. We use the preallocated
770 * splitlock so we don't have to block.
771 */
772 splitlock = *split;
773 KASSERT(splitlock != NULL, ("no split"));
774 *split = splitlock->lf_next;
775 bcopy(lock1, splitlock, sizeof *splitlock);
776 splitlock->lf_start = lock2->lf_end + 1;
777 TAILQ_INIT(&splitlock->lf_blkhd);
778 lock1->lf_end = lock2->lf_start - 1;
779 /*
780 * OK, now link it in
781 */
782 splitlock->lf_next = lock1->lf_next;
783 lock2->lf_next = splitlock;
784 lock1->lf_next = lock2;
785}
786
787/*
788 * Wakeup a blocklist
789 */
790static void
791lf_wakelock(listhead)
792 struct lockf *listhead;
793{
794 register struct lockf *wakelock;
795
796 while (!TAILQ_EMPTY(&listhead->lf_blkhd)) {
797 wakelock = TAILQ_FIRST(&listhead->lf_blkhd);
798 TAILQ_REMOVE(&listhead->lf_blkhd, wakelock, lf_block);
799 wakelock->lf_next = NOLOCKF;
800#ifdef LOCKF_DEBUG
801 if (lockf_debug & 2)
802 lf_print("lf_wakelock: awakening", wakelock);
803#endif /* LOCKF_DEBUG */
804 wakeup(wakelock);
805 }
806}
807
808#ifdef LOCKF_DEBUG
809/*
810 * Print out a lock.
811 */
812static void
813lf_print(tag, lock)
814 char *tag;
815 register struct lockf *lock;
816{
817
818 printf("%s: lock %p for ", tag, (void *)lock);
819 if (lock->lf_flags & F_POSIX)
820 printf("proc %ld", (long)((struct proc *)lock->lf_id)->p_pid);
821 else
822 printf("id %p", (void *)lock->lf_id);
823 if (lock->lf_inode != (struct inode *)0)
824 printf(" in ino %ju on dev <%s>, %s, start %jd, end %jd",
825 (uintmax_t)lock->lf_inode->i_number,
826 devtoname(lock->lf_inode->i_dev),
827 lock->lf_type == F_RDLCK ? "shared" :
828 lock->lf_type == F_WRLCK ? "exclusive" :
829 lock->lf_type == F_UNLCK ? "unlock" : "unknown",
830 (intmax_t)lock->lf_start, (intmax_t)lock->lf_end);
831 else
832 printf(" %s, start %jd, end %jd",
833 lock->lf_type == F_RDLCK ? "shared" :
834 lock->lf_type == F_WRLCK ? "exclusive" :
835 lock->lf_type == F_UNLCK ? "unlock" : "unknown",
836 (intmax_t)lock->lf_start, (intmax_t)lock->lf_end);
837 if (!TAILQ_EMPTY(&lock->lf_blkhd))
838 printf(" block %p\n", (void *)TAILQ_FIRST(&lock->lf_blkhd));
839 else
840 printf("\n");
841}
842
843static void
844lf_printlist(tag, lock)
845 char *tag;
846 struct lockf *lock;
847{
848 register struct lockf *lf, *blk;
849
850 if (lock->lf_inode == (struct inode *)0)
851 return;
852
853 printf("%s: Lock list for ino %ju on dev <%s>:\n",
854 tag, (uintmax_t)lock->lf_inode->i_number,
855 devtoname(lock->lf_inode->i_dev));
856 for (lf = lock->lf_inode->i_lockf; lf; lf = lf->lf_next) {
857 printf("\tlock %p for ",(void *)lf);
858 if (lf->lf_flags & F_POSIX)
859 printf("proc %ld",
860 (long)((struct proc *)lf->lf_id)->p_pid);
861 else
862 printf("id %p", (void *)lf->lf_id);
863 printf(", %s, start %jd, end %jd",
864 lf->lf_type == F_RDLCK ? "shared" :
865 lf->lf_type == F_WRLCK ? "exclusive" :
866 lf->lf_type == F_UNLCK ? "unlock" :
867 "unknown", (intmax_t)lf->lf_start, (intmax_t)lf->lf_end);
868 TAILQ_FOREACH(blk, &lf->lf_blkhd, lf_block) {
869 printf("\n\t\tlock request %p for ", (void *)blk);
870 if (blk->lf_flags & F_POSIX)
871 printf("proc %ld",
872 (long)((struct proc *)blk->lf_id)->p_pid);
873 else
874 printf("id %p", (void *)blk->lf_id);
875 printf(", %s, start %jd, end %jd",
876 blk->lf_type == F_RDLCK ? "shared" :
877 blk->lf_type == F_WRLCK ? "exclusive" :
878 blk->lf_type == F_UNLCK ? "unlock" :
879 "unknown", (intmax_t)blk->lf_start,
880 (intmax_t)blk->lf_end);
881 if (!TAILQ_EMPTY(&blk->lf_blkhd))
882 panic("lf_printlist: bad list");
883 }
884 printf("\n");
885 }
886}
887#endif /* LOCKF_DEBUG */
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