aboutsummaryrefslogtreecommitdiff
path: root/db2/log/log.c
blob: a9bf7a95ab93bb075117c5a461465aaafac0111a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
/*-
 * See the file LICENSE for redistribution information.
 *
 * Copyright (c) 1996, 1997
 *	Sleepycat Software.  All rights reserved.
 */
#include "config.h"

#ifndef lint
static const char sccsid[] = "@(#)log.c	10.34 (Sleepycat) 11/28/97";
#endif /* not lint */

#ifndef NO_SYSTEM_INCLUDES
#include <sys/types.h>
#include <sys/stat.h>

#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#endif

#include "db_int.h"
#include "shqueue.h"
#include "db_shash.h"
#include "log.h"
#include "db_dispatch.h"
#include "txn_auto.h"
#include "common_ext.h"

static int __log_recover __P((DB_LOG *));

/*
 * log_open --
 *	Initialize and/or join a log.
 */
int
log_open(path, flags, mode, dbenv, lpp)
	const char *path;
	int flags;
	int mode;
	DB_ENV *dbenv;
	DB_LOG **lpp;
{
	DB_LOG *dblp;
	LOG *lp;
	size_t len;
	int fd, newregion, ret, retry_cnt;

	/* Validate arguments. */
#ifdef HAVE_SPINLOCKS
#define	OKFLAGS	(DB_CREATE | DB_THREAD)
#else
#define	OKFLAGS	(DB_CREATE)
#endif
	if ((ret = __db_fchk(dbenv, "log_open", flags, OKFLAGS)) != 0)
		return (ret);

	/*
	 * We store 4-byte offsets into the file, so the maximum file
	 * size can't be larger than that.
	 */
	if (dbenv != NULL && dbenv->lg_max > UINT32_T_MAX) {
		__db_err(dbenv, "log_open: maximum file size too large");
		return (EINVAL);
	}

	/* Create and initialize the DB_LOG structure. */
	if ((dblp = (DB_LOG *)__db_calloc(1, sizeof(DB_LOG))) == NULL)
		return (ENOMEM);

	if (path != NULL && (dblp->dir = __db_strdup(path)) == NULL) {
		__db_free(dblp);
		return (ENOMEM);
	}

	dblp->dbenv = dbenv;
	dblp->lfd = -1;
	ZERO_LSN(dblp->c_lsn);
	dblp->c_fd = -1;

	/*
	 * The log region isn't fixed size because we store the registered
	 * file names there.  Make it fairly large so that we don't have to
	 * grow it.
	 */
	len = 30 * 1024;

	/* Map in the region. */
	retry_cnt = newregion = 0;
retry:	if (LF_ISSET(DB_CREATE)) {
		ret = __db_rcreate(dbenv, DB_APP_LOG, path,
		    DB_DEFAULT_LOG_FILE, mode, len, 0, &fd, &dblp->maddr);
		if (ret == 0) {
			/* Put the LOG structure first in the region. */
			lp = dblp->maddr;

			/* Initialize the rest of the region as free space. */
			dblp->addr = (u_int8_t *)dblp->maddr + sizeof(LOG);
			__db_shalloc_init(dblp->addr, len - sizeof(LOG));

			/* Initialize the LOG structure. */
			lp->persist.lg_max = dbenv == NULL ? 0 : dbenv->lg_max;
			if (lp->persist.lg_max == 0)
				lp->persist.lg_max = DEFAULT_MAX;
			lp->persist.magic = DB_LOGMAGIC;
			lp->persist.version = DB_LOGVERSION;
			lp->persist.mode = mode;
			SH_TAILQ_INIT(&lp->fq);

			/* Initialize LOG LSNs. */
			lp->lsn.file = 1;
			lp->lsn.offset = 0;

			newregion = 1;
		} else if (ret != EEXIST)
			goto err;
	}

	/* If we didn't or couldn't create the region, try and join it. */
	if (!newregion &&
	    (ret = __db_ropen(dbenv, DB_APP_LOG,
	    path, DB_DEFAULT_LOG_FILE, 0, &fd, &dblp->maddr)) != 0) {
		/*
		 * If we fail because the file isn't available, wait a
		 * second and try again.
		 */
		if (ret == EAGAIN && ++retry_cnt < 3) {
			(void)__db_sleep(1, 0);
			goto retry;
		}
		goto err;
	}

	/* Set up the common information. */
	dblp->lp = dblp->maddr;
	dblp->addr = (u_int8_t *)dblp->maddr + sizeof(LOG);
	dblp->fd = fd;

	/* Initialize thread information. */
	if (LF_ISSET(DB_THREAD)) {
		F_SET(dblp, DB_AM_THREAD);

		if (!newregion)
			LOCK_LOGREGION(dblp);
		if ((ret = __db_shalloc(dblp->addr,
		    sizeof(db_mutex_t), MUTEX_ALIGNMENT, &dblp->mutexp)) == 0)
			(void)__db_mutex_init(dblp->mutexp, -1);
		if (!newregion)
			UNLOCK_LOGREGION(dblp);
		if (ret != 0) {
			(void)log_close(dblp);
			if (newregion)
				(void)log_unlink(path, 1, dbenv);
			return (ret);
		}
	}

	/*
	 * If doing recovery, try and recover any previous log files
	 * before releasing the lock.
	 */
	if (newregion) {
		ret = __log_recover(dblp);
		UNLOCK_LOGREGION(dblp);

		if (ret != 0) {
			(void)log_close(dblp);
			(void)log_unlink(path, 1, dbenv);
			return (ret);
		}
	}
	*lpp = dblp;
	return (0);

err:	/*
	 * We never get here with an allocated thread-mutex, so we do
	 * not have to worry about freeing it.
	 */
	FREE(dblp, sizeof(DB_LOG));
	return (ret);

}

/*
 * __log_recover --
 *	Recover a log.
 */
static int
__log_recover(dblp)
	DB_LOG *dblp;
{
	DBT dbt;
	DB_LSN lsn;
	LOG *lp;
	u_int32_t chk;
	int cnt, found_checkpoint, ret;

	lp = dblp->lp;

	/*
	 * Find a log file.  If none exist, we simply return, leaving
	 * everything initialized to a new log.
	 */
	if ((ret = __log_find(dblp, &cnt)) != 0)
		return (ret);
	if (cnt == 0)
		return (0);

	/* We have a log file name, find the last one. */
	while (cnt < MAXLFNAME)
		if (__log_valid(dblp, lp, ++cnt) != 0) {
			--cnt;
			break;
		}

	/*
	 * We have the last useful log file and we've loaded any persistent
	 * information.  Pretend that the log is larger than it can possibly
	 * be, and read this file, looking for a checkpoint and its end.
	 */
	dblp->c_lsn.file = cnt;
	dblp->c_lsn.offset = 0;
	lsn = dblp->c_lsn;
	lp->lsn.file = cnt + 1;
	lp->lsn.offset = 0;

	/* Set the cursor.  Shouldn't fail, leave error messages on. */
	memset(&dbt, 0, sizeof(dbt));
	if ((ret = __log_get(dblp, &lsn, &dbt, DB_SET, 0)) != 0)
		return (ret);

	/*
	 * Read to the end of the file, saving checkpoints.  This will fail
	 * at some point, so turn off error messages.
	 */
	found_checkpoint = 0;
	while (__log_get(dblp, &lsn, &dbt, DB_NEXT, 1) == 0) {
		if (dbt.size < sizeof(u_int32_t))
			continue;
		memcpy(&chk, dbt.data, sizeof(u_int32_t));
		if (chk == DB_txn_ckp) {
			lp->c_lsn = lsn;
			found_checkpoint = 1;
		}
	}

	/*
	 * We know where the end of the log is.  Since that record is on disk,
	 * it's also the last-synced LSN.
	 */
	lp->lsn = lsn;
	lp->lsn.offset += dblp->c_len;
	lp->s_lsn = lp->lsn;

	/* Set up the current buffer information, too. */
	lp->len = dblp->c_len;
	lp->b_off = 0;
	lp->w_off = lp->lsn.offset;

	/*
	 * It's possible that we didn't find a checkpoint because there wasn't
	 * one in the last log file.  Start searching.
	 */
	while (!found_checkpoint && cnt > 1) {
		dblp->c_lsn.file = --cnt;
		dblp->c_lsn.offset = 0;
		lsn = dblp->c_lsn;

		/* Set the cursor.  Shouldn't fail, leave error messages on. */
		if ((ret = __log_get(dblp, &lsn, &dbt, DB_SET, 0)) != 0)
			return (ret);

		/*
		 * Read to the end of the file, saving checkpoints.  Shouldn't
		 * fail, leave error messages on.
		 */
		while (__log_get(dblp, &lsn, &dbt, DB_NEXT, 0) == 0) {
			if (dbt.size < sizeof(u_int32_t))
				continue;
			memcpy(&chk, dbt.data, sizeof(u_int32_t));
			if (chk == DB_txn_ckp) {
				lp->c_lsn = lsn;
				found_checkpoint = 1;
			}
		}
	}

	/* If we never find a checkpoint, that's okay, just 0 it out. */
	if (!found_checkpoint) {
		lp->c_lsn.file = 1;
		lp->c_lsn.offset = 0;
	}

	__db_err(dblp->dbenv,
	    "Recovering the log: last valid LSN: file: %lu offset %lu",
	    (u_long)lp->lsn.file, (u_long)lp->lsn.offset);

	/* Reset the cursor.  */
	ZERO_LSN(dblp->c_lsn);

	return (0);
}

/*
 * __log_find --
 *	Try to find a log file.
 *
 * PUBLIC: int __log_find __P((DB_LOG *, int *));
 */
int
__log_find(dblp, valp)
	DB_LOG *dblp;
	int *valp;
{
	int cnt, fcnt, logval, ret;
	const char *dir;
	char **names, *p, *q;

	/* Find the directory name. */
	if ((ret = __log_name(dblp, 1, &p)) != 0)
		return (ret);
	if ((q = __db_rpath(p)) == NULL)
		dir = PATH_DOT;
	else {
		*q = '\0';
		dir = p;
	}

	/* Get the list of file names. */
	ret = __db_dirlist(dir, &names, &fcnt);
	FREES(p);
	if (ret != 0) {
		__db_err(dblp->dbenv, "%s: %s", dir, strerror(ret));
		return (ret);
	}

	/*
	 * Search for a valid log file name, return a value of 0 on
	 * failure.
	 */
	*valp = 0;
	for (cnt = fcnt, logval = 0; --cnt >= 0;)
		if (strncmp(names[cnt], "log.", sizeof("log.") - 1) == 0) {
			logval = atoi(names[cnt] + 4);
			if (logval != 0 &&
			    __log_valid(dblp, dblp->lp, logval) == 0) {
				*valp = logval;
				break;
			}
		}

	/* Discard the list. */
	__db_dirfree(names, fcnt);

	return (ret);
}

/*
 * log_valid --
 *	Validate a log file.
 *
 * PUBLIC: int __log_valid __P((DB_LOG *, LOG *, int));
 */
int
__log_valid(dblp, lp, cnt)
	DB_LOG *dblp;
	LOG *lp;
	int cnt;
{
	LOGP persist;
	ssize_t nw;
	int fd, ret;
	char *p;

	if ((ret = __log_name(dblp, cnt, &p)) != 0)
		return (ret);

	fd = -1;
	if ((ret = __db_open(p,
	    DB_RDONLY | DB_SEQUENTIAL,
	    DB_RDONLY | DB_SEQUENTIAL, 0, &fd)) != 0 ||
	    (ret = __db_seek(fd, 0, 0, sizeof(HDR), SEEK_SET)) != 0 ||
	    (ret = __db_read(fd, &persist, sizeof(LOGP), &nw)) != 0 ||
	    nw != sizeof(LOGP)) {
		if (ret == 0)
			ret = EIO;
		if (fd != -1) {
			(void)__db_close(fd);
			__db_err(dblp->dbenv,
			    "Ignoring log file: %s: %s", p, strerror(ret));
		}
		goto err;
	}
	(void)__db_close(fd);

	if (persist.magic != DB_LOGMAGIC) {
		__db_err(dblp->dbenv,
		    "Ignoring log file: %s: magic number %lx, not %lx",
		    p, (u_long)persist.magic, (u_long)DB_LOGMAGIC);
		ret = EINVAL;
		goto err;
	}
	if (persist.version < DB_LOGOLDVER || persist.version > DB_LOGVERSION) {
		__db_err(dblp->dbenv,
		    "Ignoring log file: %s: unsupported log version %lu",
		    p, (u_long)persist.version);
		ret = EINVAL;
		goto err;
	}

	if (lp != NULL) {
		lp->persist.lg_max = persist.lg_max;
		lp->persist.mode = persist.mode;
	}
	ret = 0;

err:	FREES(p);
	return (ret);
}

/*
 * log_close --
 *	Close a log.
 */
int
log_close(dblp)
	DB_LOG *dblp;
{
	int ret, t_ret;

	ret = 0;

	/* Discard the per-thread pointer. */
	if (dblp->mutexp != NULL) {
		LOCK_LOGREGION(dblp);
		__db_shalloc_free(dblp->addr, dblp->mutexp);
		UNLOCK_LOGREGION(dblp);
	}

	/* Close the region. */
	if ((t_ret =
	    __db_rclose(dblp->dbenv, dblp->fd, dblp->maddr)) != 0 && ret == 0)
		ret = t_ret;

	/* Close open files, release allocated memory. */
	if (dblp->lfd != -1 && (t_ret = __db_close(dblp->lfd)) != 0 && ret == 0)
		ret = t_ret;
	if (dblp->c_dbt.data != NULL)
		FREE(dblp->c_dbt.data, dblp->c_dbt.ulen);
	if (dblp->c_fd != -1 &&
	    (t_ret = __db_close(dblp->c_fd)) != 0 && ret == 0)
		ret = t_ret;
	if (dblp->dbentry != NULL)
		FREE(dblp->dbentry, (dblp->dbentry_cnt * sizeof(DB_ENTRY)));
	if (dblp->dir != NULL)
		FREES(dblp->dir);

	/* Free the structure. */
	FREE(dblp, sizeof(DB_LOG));

	return (ret);
}

/*
 * log_unlink --
 *	Exit a log.
 */
int
log_unlink(path, force, dbenv)
	const char *path;
	int force;
	DB_ENV *dbenv;
{
	return (__db_runlink(dbenv,
	    DB_APP_LOG, path, DB_DEFAULT_LOG_FILE, force));
}

/*
 * log_stat --
 *	Return LOG statistics.
 */
int
log_stat(dblp, gspp, db_malloc)
	DB_LOG *dblp;
	DB_LOG_STAT **gspp;
	void *(*db_malloc) __P((size_t));
{
	LOG *lp;

	*gspp = NULL;
	lp = dblp->lp;

	if ((*gspp = db_malloc == NULL ?
	    (DB_LOG_STAT *)__db_malloc(sizeof(**gspp)) :
	    (DB_LOG_STAT *)db_malloc(sizeof(**gspp))) == NULL)
		return (ENOMEM);

	/* Copy out the global statistics. */
	LOCK_LOGREGION(dblp);
	**gspp = lp->stat;

	(*gspp)->st_magic = lp->persist.magic;
	(*gspp)->st_version = lp->persist.version;
	(*gspp)->st_mode = lp->persist.mode;
	(*gspp)->st_lg_max = lp->persist.lg_max;

	(*gspp)->st_region_nowait = lp->rlayout.lock.mutex_set_nowait;
	(*gspp)->st_region_wait = lp->rlayout.lock.mutex_set_wait;
	UNLOCK_LOGREGION(dblp);

	return (0);
}