xref: /linux/drivers/md/dm-log.c (revision 8fa5723aa7e053d498336b48448b292fc2e0458b) 
1 /*
2  * Copyright (C) 2003 Sistina Software
3  * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
4  *
5  * This file is released under the LGPL.
6  */
7 
8 #include <linux/init.h>
9 #include <linux/slab.h>
10 #include <linux/module.h>
11 #include <linux/vmalloc.h>
12 #include <linux/dm-io.h>
13 #include <linux/dm-dirty-log.h>
14 
15 #include <linux/device-mapper.h>
16 
17 #define DM_MSG_PREFIX "dirty region log"
18 
19 struct dm_dirty_log_internal {
20 	struct dm_dirty_log_type *type;
21 
22 	struct list_head list;
23 	long use;
24 };
25 
26 static LIST_HEAD(_log_types);
27 static DEFINE_SPINLOCK(_lock);
28 
29 static struct dm_dirty_log_internal *__find_dirty_log_type(const char *name)
30 {
31 	struct dm_dirty_log_internal *log_type;
32 
33 	list_for_each_entry(log_type, &_log_types, list)
34 		if (!strcmp(name, log_type->type->name))
35 			return log_type;
36 
37 	return NULL;
38 }
39 
40 static struct dm_dirty_log_internal *_get_dirty_log_type(const char *name)
41 {
42 	struct dm_dirty_log_internal *log_type;
43 
44 	spin_lock(&_lock);
45 
46 	log_type = __find_dirty_log_type(name);
47 	if (log_type) {
48 		if (!log_type->use && !try_module_get(log_type->type->module))
49 			log_type = NULL;
50 		else
51 			log_type->use++;
52 	}
53 
54 	spin_unlock(&_lock);
55 
56 	return log_type;
57 }
58 
59 /*
60  * get_type
61  * @type_name
62  *
63  * Attempt to retrieve the dm_dirty_log_type by name.  If not already
64  * available, attempt to load the appropriate module.
65  *
66  * Log modules are named "dm-log-" followed by the 'type_name'.
67  * Modules may contain multiple types.
68  * This function will first try the module "dm-log-<type_name>",
69  * then truncate 'type_name' on the last '-' and try again.
70  *
71  * For example, if type_name was "clustered-disk", it would search
72  * 'dm-log-clustered-disk' then 'dm-log-clustered'.
73  *
74  * Returns: dirty_log_type* on success, NULL on failure
75  */
76 static struct dm_dirty_log_type *get_type(const char *type_name)
77 {
78 	char *p, *type_name_dup;
79 	struct dm_dirty_log_internal *log_type;
80 
81 	if (!type_name)
82 		return NULL;
83 
84 	log_type = _get_dirty_log_type(type_name);
85 	if (log_type)
86 		return log_type->type;
87 
88 	type_name_dup = kstrdup(type_name, GFP_KERNEL);
89 	if (!type_name_dup) {
90 		DMWARN("No memory left to attempt log module load for \"%s\"",
91 		       type_name);
92 		return NULL;
93 	}
94 
95 	while (request_module("dm-log-%s", type_name_dup) ||
96 	       !(log_type = _get_dirty_log_type(type_name))) {
97 		p = strrchr(type_name_dup, '-');
98 		if (!p)
99 			break;
100 		p[0] = '\0';
101 	}
102 
103 	if (!log_type)
104 		DMWARN("Module for logging type \"%s\" not found.", type_name);
105 
106 	kfree(type_name_dup);
107 
108 	return log_type ? log_type->type : NULL;
109 }
110 
111 static void put_type(struct dm_dirty_log_type *type)
112 {
113 	struct dm_dirty_log_internal *log_type;
114 
115 	if (!type)
116 		return;
117 
118 	spin_lock(&_lock);
119 	log_type = __find_dirty_log_type(type->name);
120 	if (!log_type)
121 		goto out;
122 
123 	if (!--log_type->use)
124 		module_put(type->module);
125 
126 	BUG_ON(log_type->use < 0);
127 
128 out:
129 	spin_unlock(&_lock);
130 }
131 
132 static struct dm_dirty_log_internal *_alloc_dirty_log_type(struct dm_dirty_log_type *type)
133 {
134 	struct dm_dirty_log_internal *log_type = kzalloc(sizeof(*log_type),
135 							 GFP_KERNEL);
136 
137 	if (log_type)
138 		log_type->type = type;
139 
140 	return log_type;
141 }
142 
143 int dm_dirty_log_type_register(struct dm_dirty_log_type *type)
144 {
145 	struct dm_dirty_log_internal *log_type = _alloc_dirty_log_type(type);
146 	int r = 0;
147 
148 	if (!log_type)
149 		return -ENOMEM;
150 
151 	spin_lock(&_lock);
152 	if (!__find_dirty_log_type(type->name))
153 		list_add(&log_type->list, &_log_types);
154 	else {
155 		kfree(log_type);
156 		r = -EEXIST;
157 	}
158 	spin_unlock(&_lock);
159 
160 	return r;
161 }
162 EXPORT_SYMBOL(dm_dirty_log_type_register);
163 
164 int dm_dirty_log_type_unregister(struct dm_dirty_log_type *type)
165 {
166 	struct dm_dirty_log_internal *log_type;
167 
168 	spin_lock(&_lock);
169 
170 	log_type = __find_dirty_log_type(type->name);
171 	if (!log_type) {
172 		spin_unlock(&_lock);
173 		return -EINVAL;
174 	}
175 
176 	if (log_type->use) {
177 		spin_unlock(&_lock);
178 		return -ETXTBSY;
179 	}
180 
181 	list_del(&log_type->list);
182 
183 	spin_unlock(&_lock);
184 	kfree(log_type);
185 
186 	return 0;
187 }
188 EXPORT_SYMBOL(dm_dirty_log_type_unregister);
189 
190 struct dm_dirty_log *dm_dirty_log_create(const char *type_name,
191 					 struct dm_target *ti,
192 					 unsigned int argc, char **argv)
193 {
194 	struct dm_dirty_log_type *type;
195 	struct dm_dirty_log *log;
196 
197 	log = kmalloc(sizeof(*log), GFP_KERNEL);
198 	if (!log)
199 		return NULL;
200 
201 	type = get_type(type_name);
202 	if (!type) {
203 		kfree(log);
204 		return NULL;
205 	}
206 
207 	log->type = type;
208 	if (type->ctr(log, ti, argc, argv)) {
209 		kfree(log);
210 		put_type(type);
211 		return NULL;
212 	}
213 
214 	return log;
215 }
216 EXPORT_SYMBOL(dm_dirty_log_create);
217 
218 void dm_dirty_log_destroy(struct dm_dirty_log *log)
219 {
220 	log->type->dtr(log);
221 	put_type(log->type);
222 	kfree(log);
223 }
224 EXPORT_SYMBOL(dm_dirty_log_destroy);
225 
226 /*-----------------------------------------------------------------
227  * Persistent and core logs share a lot of their implementation.
228  * FIXME: need a reload method to be called from a resume
229  *---------------------------------------------------------------*/
230 /*
231  * Magic for persistent mirrors: "MiRr"
232  */
233 #define MIRROR_MAGIC 0x4D695272
234 
235 /*
236  * The on-disk version of the metadata.
237  */
238 #define MIRROR_DISK_VERSION 2
239 #define LOG_OFFSET 2
240 
241 struct log_header {
242 	uint32_t magic;
243 
244 	/*
245 	 * Simple, incrementing version. no backward
246 	 * compatibility.
247 	 */
248 	uint32_t version;
249 	sector_t nr_regions;
250 };
251 
252 struct log_c {
253 	struct dm_target *ti;
254 	int touched;
255 	uint32_t region_size;
256 	unsigned int region_count;
257 	region_t sync_count;
258 
259 	unsigned bitset_uint32_count;
260 	uint32_t *clean_bits;
261 	uint32_t *sync_bits;
262 	uint32_t *recovering_bits;	/* FIXME: this seems excessive */
263 
264 	int sync_search;
265 
266 	/* Resync flag */
267 	enum sync {
268 		DEFAULTSYNC,	/* Synchronize if necessary */
269 		NOSYNC,		/* Devices known to be already in sync */
270 		FORCESYNC,	/* Force a sync to happen */
271 	} sync;
272 
273 	struct dm_io_request io_req;
274 
275 	/*
276 	 * Disk log fields
277 	 */
278 	int log_dev_failed;
279 	struct dm_dev *log_dev;
280 	struct log_header header;
281 
282 	struct dm_io_region header_location;
283 	struct log_header *disk_header;
284 };
285 
286 /*
287  * The touched member needs to be updated every time we access
288  * one of the bitsets.
289  */
290 static inline int log_test_bit(uint32_t *bs, unsigned bit)
291 {
292 	return ext2_test_bit(bit, (unsigned long *) bs) ? 1 : 0;
293 }
294 
295 static inline void log_set_bit(struct log_c *l,
296 			       uint32_t *bs, unsigned bit)
297 {
298 	ext2_set_bit(bit, (unsigned long *) bs);
299 	l->touched = 1;
300 }
301 
302 static inline void log_clear_bit(struct log_c *l,
303 				 uint32_t *bs, unsigned bit)
304 {
305 	ext2_clear_bit(bit, (unsigned long *) bs);
306 	l->touched = 1;
307 }
308 
309 /*----------------------------------------------------------------
310  * Header IO
311  *--------------------------------------------------------------*/
312 static void header_to_disk(struct log_header *core, struct log_header *disk)
313 {
314 	disk->magic = cpu_to_le32(core->magic);
315 	disk->version = cpu_to_le32(core->version);
316 	disk->nr_regions = cpu_to_le64(core->nr_regions);
317 }
318 
319 static void header_from_disk(struct log_header *core, struct log_header *disk)
320 {
321 	core->magic = le32_to_cpu(disk->magic);
322 	core->version = le32_to_cpu(disk->version);
323 	core->nr_regions = le64_to_cpu(disk->nr_regions);
324 }
325 
326 static int rw_header(struct log_c *lc, int rw)
327 {
328 	lc->io_req.bi_rw = rw;
329 	lc->io_req.mem.ptr.vma = lc->disk_header;
330 	lc->io_req.notify.fn = NULL;
331 
332 	return dm_io(&lc->io_req, 1, &lc->header_location, NULL);
333 }
334 
335 static int read_header(struct log_c *log)
336 {
337 	int r;
338 
339 	r = rw_header(log, READ);
340 	if (r)
341 		return r;
342 
343 	header_from_disk(&log->header, log->disk_header);
344 
345 	/* New log required? */
346 	if (log->sync != DEFAULTSYNC || log->header.magic != MIRROR_MAGIC) {
347 		log->header.magic = MIRROR_MAGIC;
348 		log->header.version = MIRROR_DISK_VERSION;
349 		log->header.nr_regions = 0;
350 	}
351 
352 #ifdef __LITTLE_ENDIAN
353 	if (log->header.version == 1)
354 		log->header.version = 2;
355 #endif
356 
357 	if (log->header.version != MIRROR_DISK_VERSION) {
358 		DMWARN("incompatible disk log version");
359 		return -EINVAL;
360 	}
361 
362 	return 0;
363 }
364 
365 static inline int write_header(struct log_c *log)
366 {
367 	header_to_disk(&log->header, log->disk_header);
368 	return rw_header(log, WRITE);
369 }
370 
371 /*----------------------------------------------------------------
372  * core log constructor/destructor
373  *
374  * argv contains region_size followed optionally by [no]sync
375  *--------------------------------------------------------------*/
376 #define BYTE_SHIFT 3
377 static int create_log_context(struct dm_dirty_log *log, struct dm_target *ti,
378 			      unsigned int argc, char **argv,
379 			      struct dm_dev *dev)
380 {
381 	enum sync sync = DEFAULTSYNC;
382 
383 	struct log_c *lc;
384 	uint32_t region_size;
385 	unsigned int region_count;
386 	size_t bitset_size, buf_size;
387 	int r;
388 
389 	if (argc < 1 || argc > 2) {
390 		DMWARN("wrong number of arguments to dirty region log");
391 		return -EINVAL;
392 	}
393 
394 	if (argc > 1) {
395 		if (!strcmp(argv[1], "sync"))
396 			sync = FORCESYNC;
397 		else if (!strcmp(argv[1], "nosync"))
398 			sync = NOSYNC;
399 		else {
400 			DMWARN("unrecognised sync argument to "
401 			       "dirty region log: %s", argv[1]);
402 			return -EINVAL;
403 		}
404 	}
405 
406 	if (sscanf(argv[0], "%u", &region_size) != 1) {
407 		DMWARN("invalid region size string");
408 		return -EINVAL;
409 	}
410 
411 	region_count = dm_sector_div_up(ti->len, region_size);
412 
413 	lc = kmalloc(sizeof(*lc), GFP_KERNEL);
414 	if (!lc) {
415 		DMWARN("couldn't allocate core log");
416 		return -ENOMEM;
417 	}
418 
419 	lc->ti = ti;
420 	lc->touched = 0;
421 	lc->region_size = region_size;
422 	lc->region_count = region_count;
423 	lc->sync = sync;
424 
425 	/*
426 	 * Work out how many "unsigned long"s we need to hold the bitset.
427 	 */
428 	bitset_size = dm_round_up(region_count,
429 				  sizeof(*lc->clean_bits) << BYTE_SHIFT);
430 	bitset_size >>= BYTE_SHIFT;
431 
432 	lc->bitset_uint32_count = bitset_size / sizeof(*lc->clean_bits);
433 
434 	/*
435 	 * Disk log?
436 	 */
437 	if (!dev) {
438 		lc->clean_bits = vmalloc(bitset_size);
439 		if (!lc->clean_bits) {
440 			DMWARN("couldn't allocate clean bitset");
441 			kfree(lc);
442 			return -ENOMEM;
443 		}
444 		lc->disk_header = NULL;
445 	} else {
446 		lc->log_dev = dev;
447 		lc->log_dev_failed = 0;
448 		lc->header_location.bdev = lc->log_dev->bdev;
449 		lc->header_location.sector = 0;
450 
451 		/*
452 		 * Buffer holds both header and bitset.
453 		 */
454 		buf_size = dm_round_up((LOG_OFFSET << SECTOR_SHIFT) +
455 				       bitset_size, ti->limits.hardsect_size);
456 		lc->header_location.count = buf_size >> SECTOR_SHIFT;
457 		lc->io_req.mem.type = DM_IO_VMA;
458 		lc->io_req.client = dm_io_client_create(dm_div_up(buf_size,
459 								   PAGE_SIZE));
460 		if (IS_ERR(lc->io_req.client)) {
461 			r = PTR_ERR(lc->io_req.client);
462 			DMWARN("couldn't allocate disk io client");
463 			kfree(lc);
464 			return -ENOMEM;
465 		}
466 
467 		lc->disk_header = vmalloc(buf_size);
468 		if (!lc->disk_header) {
469 			DMWARN("couldn't allocate disk log buffer");
470 			kfree(lc);
471 			return -ENOMEM;
472 		}
473 
474 		lc->clean_bits = (void *)lc->disk_header +
475 				 (LOG_OFFSET << SECTOR_SHIFT);
476 	}
477 
478 	memset(lc->clean_bits, -1, bitset_size);
479 
480 	lc->sync_bits = vmalloc(bitset_size);
481 	if (!lc->sync_bits) {
482 		DMWARN("couldn't allocate sync bitset");
483 		if (!dev)
484 			vfree(lc->clean_bits);
485 		vfree(lc->disk_header);
486 		kfree(lc);
487 		return -ENOMEM;
488 	}
489 	memset(lc->sync_bits, (sync == NOSYNC) ? -1 : 0, bitset_size);
490 	lc->sync_count = (sync == NOSYNC) ? region_count : 0;
491 
492 	lc->recovering_bits = vmalloc(bitset_size);
493 	if (!lc->recovering_bits) {
494 		DMWARN("couldn't allocate sync bitset");
495 		vfree(lc->sync_bits);
496 		if (!dev)
497 			vfree(lc->clean_bits);
498 		vfree(lc->disk_header);
499 		kfree(lc);
500 		return -ENOMEM;
501 	}
502 	memset(lc->recovering_bits, 0, bitset_size);
503 	lc->sync_search = 0;
504 	log->context = lc;
505 
506 	return 0;
507 }
508 
509 static int core_ctr(struct dm_dirty_log *log, struct dm_target *ti,
510 		    unsigned int argc, char **argv)
511 {
512 	return create_log_context(log, ti, argc, argv, NULL);
513 }
514 
515 static void destroy_log_context(struct log_c *lc)
516 {
517 	vfree(lc->sync_bits);
518 	vfree(lc->recovering_bits);
519 	kfree(lc);
520 }
521 
522 static void core_dtr(struct dm_dirty_log *log)
523 {
524 	struct log_c *lc = (struct log_c *) log->context;
525 
526 	vfree(lc->clean_bits);
527 	destroy_log_context(lc);
528 }
529 
530 /*----------------------------------------------------------------
531  * disk log constructor/destructor
532  *
533  * argv contains log_device region_size followed optionally by [no]sync
534  *--------------------------------------------------------------*/
535 static int disk_ctr(struct dm_dirty_log *log, struct dm_target *ti,
536 		    unsigned int argc, char **argv)
537 {
538 	int r;
539 	struct dm_dev *dev;
540 
541 	if (argc < 2 || argc > 3) {
542 		DMWARN("wrong number of arguments to disk dirty region log");
543 		return -EINVAL;
544 	}
545 
546 	r = dm_get_device(ti, argv[0], 0, 0 /* FIXME */,
547 			  FMODE_READ | FMODE_WRITE, &dev);
548 	if (r)
549 		return r;
550 
551 	r = create_log_context(log, ti, argc - 1, argv + 1, dev);
552 	if (r) {
553 		dm_put_device(ti, dev);
554 		return r;
555 	}
556 
557 	return 0;
558 }
559 
560 static void disk_dtr(struct dm_dirty_log *log)
561 {
562 	struct log_c *lc = (struct log_c *) log->context;
563 
564 	dm_put_device(lc->ti, lc->log_dev);
565 	vfree(lc->disk_header);
566 	dm_io_client_destroy(lc->io_req.client);
567 	destroy_log_context(lc);
568 }
569 
570 static int count_bits32(uint32_t *addr, unsigned size)
571 {
572 	int count = 0, i;
573 
574 	for (i = 0; i < size; i++) {
575 		count += hweight32(*(addr+i));
576 	}
577 	return count;
578 }
579 
580 static void fail_log_device(struct log_c *lc)
581 {
582 	if (lc->log_dev_failed)
583 		return;
584 
585 	lc->log_dev_failed = 1;
586 	dm_table_event(lc->ti->table);
587 }
588 
589 static int disk_resume(struct dm_dirty_log *log)
590 {
591 	int r;
592 	unsigned i;
593 	struct log_c *lc = (struct log_c *) log->context;
594 	size_t size = lc->bitset_uint32_count * sizeof(uint32_t);
595 
596 	/* read the disk header */
597 	r = read_header(lc);
598 	if (r) {
599 		DMWARN("%s: Failed to read header on dirty region log device",
600 		       lc->log_dev->name);
601 		fail_log_device(lc);
602 		/*
603 		 * If the log device cannot be read, we must assume
604 		 * all regions are out-of-sync.  If we simply return
605 		 * here, the state will be uninitialized and could
606 		 * lead us to return 'in-sync' status for regions
607 		 * that are actually 'out-of-sync'.
608 		 */
609 		lc->header.nr_regions = 0;
610 	}
611 
612 	/* set or clear any new bits -- device has grown */
613 	if (lc->sync == NOSYNC)
614 		for (i = lc->header.nr_regions; i < lc->region_count; i++)
615 			/* FIXME: amazingly inefficient */
616 			log_set_bit(lc, lc->clean_bits, i);
617 	else
618 		for (i = lc->header.nr_regions; i < lc->region_count; i++)
619 			/* FIXME: amazingly inefficient */
620 			log_clear_bit(lc, lc->clean_bits, i);
621 
622 	/* clear any old bits -- device has shrunk */
623 	for (i = lc->region_count; i % (sizeof(*lc->clean_bits) << BYTE_SHIFT); i++)
624 		log_clear_bit(lc, lc->clean_bits, i);
625 
626 	/* copy clean across to sync */
627 	memcpy(lc->sync_bits, lc->clean_bits, size);
628 	lc->sync_count = count_bits32(lc->clean_bits, lc->bitset_uint32_count);
629 	lc->sync_search = 0;
630 
631 	/* set the correct number of regions in the header */
632 	lc->header.nr_regions = lc->region_count;
633 
634 	/* write the new header */
635 	r = write_header(lc);
636 	if (r) {
637 		DMWARN("%s: Failed to write header on dirty region log device",
638 		       lc->log_dev->name);
639 		fail_log_device(lc);
640 	}
641 
642 	return r;
643 }
644 
645 static uint32_t core_get_region_size(struct dm_dirty_log *log)
646 {
647 	struct log_c *lc = (struct log_c *) log->context;
648 	return lc->region_size;
649 }
650 
651 static int core_resume(struct dm_dirty_log *log)
652 {
653 	struct log_c *lc = (struct log_c *) log->context;
654 	lc->sync_search = 0;
655 	return 0;
656 }
657 
658 static int core_is_clean(struct dm_dirty_log *log, region_t region)
659 {
660 	struct log_c *lc = (struct log_c *) log->context;
661 	return log_test_bit(lc->clean_bits, region);
662 }
663 
664 static int core_in_sync(struct dm_dirty_log *log, region_t region, int block)
665 {
666 	struct log_c *lc = (struct log_c *) log->context;
667 	return log_test_bit(lc->sync_bits, region);
668 }
669 
670 static int core_flush(struct dm_dirty_log *log)
671 {
672 	/* no op */
673 	return 0;
674 }
675 
676 static int disk_flush(struct dm_dirty_log *log)
677 {
678 	int r;
679 	struct log_c *lc = (struct log_c *) log->context;
680 
681 	/* only write if the log has changed */
682 	if (!lc->touched)
683 		return 0;
684 
685 	r = write_header(lc);
686 	if (r)
687 		fail_log_device(lc);
688 	else
689 		lc->touched = 0;
690 
691 	return r;
692 }
693 
694 static void core_mark_region(struct dm_dirty_log *log, region_t region)
695 {
696 	struct log_c *lc = (struct log_c *) log->context;
697 	log_clear_bit(lc, lc->clean_bits, region);
698 }
699 
700 static void core_clear_region(struct dm_dirty_log *log, region_t region)
701 {
702 	struct log_c *lc = (struct log_c *) log->context;
703 	log_set_bit(lc, lc->clean_bits, region);
704 }
705 
706 static int core_get_resync_work(struct dm_dirty_log *log, region_t *region)
707 {
708 	struct log_c *lc = (struct log_c *) log->context;
709 
710 	if (lc->sync_search >= lc->region_count)
711 		return 0;
712 
713 	do {
714 		*region = ext2_find_next_zero_bit(
715 					     (unsigned long *) lc->sync_bits,
716 					     lc->region_count,
717 					     lc->sync_search);
718 		lc->sync_search = *region + 1;
719 
720 		if (*region >= lc->region_count)
721 			return 0;
722 
723 	} while (log_test_bit(lc->recovering_bits, *region));
724 
725 	log_set_bit(lc, lc->recovering_bits, *region);
726 	return 1;
727 }
728 
729 static void core_set_region_sync(struct dm_dirty_log *log, region_t region,
730 				 int in_sync)
731 {
732 	struct log_c *lc = (struct log_c *) log->context;
733 
734 	log_clear_bit(lc, lc->recovering_bits, region);
735 	if (in_sync) {
736 		log_set_bit(lc, lc->sync_bits, region);
737                 lc->sync_count++;
738         } else if (log_test_bit(lc->sync_bits, region)) {
739 		lc->sync_count--;
740 		log_clear_bit(lc, lc->sync_bits, region);
741 	}
742 }
743 
744 static region_t core_get_sync_count(struct dm_dirty_log *log)
745 {
746         struct log_c *lc = (struct log_c *) log->context;
747 
748         return lc->sync_count;
749 }
750 
751 #define	DMEMIT_SYNC \
752 	if (lc->sync != DEFAULTSYNC) \
753 		DMEMIT("%ssync ", lc->sync == NOSYNC ? "no" : "")
754 
755 static int core_status(struct dm_dirty_log *log, status_type_t status,
756 		       char *result, unsigned int maxlen)
757 {
758 	int sz = 0;
759 	struct log_c *lc = log->context;
760 
761 	switch(status) {
762 	case STATUSTYPE_INFO:
763 		DMEMIT("1 %s", log->type->name);
764 		break;
765 
766 	case STATUSTYPE_TABLE:
767 		DMEMIT("%s %u %u ", log->type->name,
768 		       lc->sync == DEFAULTSYNC ? 1 : 2, lc->region_size);
769 		DMEMIT_SYNC;
770 	}
771 
772 	return sz;
773 }
774 
775 static int disk_status(struct dm_dirty_log *log, status_type_t status,
776 		       char *result, unsigned int maxlen)
777 {
778 	int sz = 0;
779 	struct log_c *lc = log->context;
780 
781 	switch(status) {
782 	case STATUSTYPE_INFO:
783 		DMEMIT("3 %s %s %c", log->type->name, lc->log_dev->name,
784 		       lc->log_dev_failed ? 'D' : 'A');
785 		break;
786 
787 	case STATUSTYPE_TABLE:
788 		DMEMIT("%s %u %s %u ", log->type->name,
789 		       lc->sync == DEFAULTSYNC ? 2 : 3, lc->log_dev->name,
790 		       lc->region_size);
791 		DMEMIT_SYNC;
792 	}
793 
794 	return sz;
795 }
796 
797 static struct dm_dirty_log_type _core_type = {
798 	.name = "core",
799 	.module = THIS_MODULE,
800 	.ctr = core_ctr,
801 	.dtr = core_dtr,
802 	.resume = core_resume,
803 	.get_region_size = core_get_region_size,
804 	.is_clean = core_is_clean,
805 	.in_sync = core_in_sync,
806 	.flush = core_flush,
807 	.mark_region = core_mark_region,
808 	.clear_region = core_clear_region,
809 	.get_resync_work = core_get_resync_work,
810 	.set_region_sync = core_set_region_sync,
811 	.get_sync_count = core_get_sync_count,
812 	.status = core_status,
813 };
814 
815 static struct dm_dirty_log_type _disk_type = {
816 	.name = "disk",
817 	.module = THIS_MODULE,
818 	.ctr = disk_ctr,
819 	.dtr = disk_dtr,
820 	.postsuspend = disk_flush,
821 	.resume = disk_resume,
822 	.get_region_size = core_get_region_size,
823 	.is_clean = core_is_clean,
824 	.in_sync = core_in_sync,
825 	.flush = disk_flush,
826 	.mark_region = core_mark_region,
827 	.clear_region = core_clear_region,
828 	.get_resync_work = core_get_resync_work,
829 	.set_region_sync = core_set_region_sync,
830 	.get_sync_count = core_get_sync_count,
831 	.status = disk_status,
832 };
833 
834 static int __init dm_dirty_log_init(void)
835 {
836 	int r;
837 
838 	r = dm_dirty_log_type_register(&_core_type);
839 	if (r)
840 		DMWARN("couldn't register core log");
841 
842 	r = dm_dirty_log_type_register(&_disk_type);
843 	if (r) {
844 		DMWARN("couldn't register disk type");
845 		dm_dirty_log_type_unregister(&_core_type);
846 	}
847 
848 	return r;
849 }
850 
851 static void __exit dm_dirty_log_exit(void)
852 {
853 	dm_dirty_log_type_unregister(&_disk_type);
854 	dm_dirty_log_type_unregister(&_core_type);
855 }
856 
857 module_init(dm_dirty_log_init);
858 module_exit(dm_dirty_log_exit);
859 
860 MODULE_DESCRIPTION(DM_NAME " dirty region log");
861 MODULE_AUTHOR("Joe Thornber, Heinz Mauelshagen <dm-devel@redhat.com>");
862 MODULE_LICENSE("GPL");
863