xref: /linux/drivers/md/dm-log.c (revision b233b28eac0cc37d07c2d007ea08c86c778c5af4) 
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 
330 	return dm_io(&lc->io_req, 1, &lc->header_location, NULL);
331 }
332 
333 static int read_header(struct log_c *log)
334 {
335 	int r;
336 
337 	r = rw_header(log, READ);
338 	if (r)
339 		return r;
340 
341 	header_from_disk(&log->header, log->disk_header);
342 
343 	/* New log required? */
344 	if (log->sync != DEFAULTSYNC || log->header.magic != MIRROR_MAGIC) {
345 		log->header.magic = MIRROR_MAGIC;
346 		log->header.version = MIRROR_DISK_VERSION;
347 		log->header.nr_regions = 0;
348 	}
349 
350 #ifdef __LITTLE_ENDIAN
351 	if (log->header.version == 1)
352 		log->header.version = 2;
353 #endif
354 
355 	if (log->header.version != MIRROR_DISK_VERSION) {
356 		DMWARN("incompatible disk log version");
357 		return -EINVAL;
358 	}
359 
360 	return 0;
361 }
362 
363 static int _check_region_size(struct dm_target *ti, uint32_t region_size)
364 {
365 	if (region_size < 2 || region_size > ti->len)
366 		return 0;
367 
368 	if (!is_power_of_2(region_size))
369 		return 0;
370 
371 	return 1;
372 }
373 
374 /*----------------------------------------------------------------
375  * core log constructor/destructor
376  *
377  * argv contains region_size followed optionally by [no]sync
378  *--------------------------------------------------------------*/
379 #define BYTE_SHIFT 3
380 static int create_log_context(struct dm_dirty_log *log, struct dm_target *ti,
381 			      unsigned int argc, char **argv,
382 			      struct dm_dev *dev)
383 {
384 	enum sync sync = DEFAULTSYNC;
385 
386 	struct log_c *lc;
387 	uint32_t region_size;
388 	unsigned int region_count;
389 	size_t bitset_size, buf_size;
390 	int r;
391 
392 	if (argc < 1 || argc > 2) {
393 		DMWARN("wrong number of arguments to dirty region log");
394 		return -EINVAL;
395 	}
396 
397 	if (argc > 1) {
398 		if (!strcmp(argv[1], "sync"))
399 			sync = FORCESYNC;
400 		else if (!strcmp(argv[1], "nosync"))
401 			sync = NOSYNC;
402 		else {
403 			DMWARN("unrecognised sync argument to "
404 			       "dirty region log: %s", argv[1]);
405 			return -EINVAL;
406 		}
407 	}
408 
409 	if (sscanf(argv[0], "%u", &region_size) != 1 ||
410 	    !_check_region_size(ti, region_size)) {
411 		DMWARN("invalid region size %s", argv[0]);
412 		return -EINVAL;
413 	}
414 
415 	region_count = dm_sector_div_up(ti->len, region_size);
416 
417 	lc = kmalloc(sizeof(*lc), GFP_KERNEL);
418 	if (!lc) {
419 		DMWARN("couldn't allocate core log");
420 		return -ENOMEM;
421 	}
422 
423 	lc->ti = ti;
424 	lc->touched = 0;
425 	lc->region_size = region_size;
426 	lc->region_count = region_count;
427 	lc->sync = sync;
428 
429 	/*
430 	 * Work out how many "unsigned long"s we need to hold the bitset.
431 	 */
432 	bitset_size = dm_round_up(region_count,
433 				  sizeof(*lc->clean_bits) << BYTE_SHIFT);
434 	bitset_size >>= BYTE_SHIFT;
435 
436 	lc->bitset_uint32_count = bitset_size / sizeof(*lc->clean_bits);
437 
438 	/*
439 	 * Disk log?
440 	 */
441 	if (!dev) {
442 		lc->clean_bits = vmalloc(bitset_size);
443 		if (!lc->clean_bits) {
444 			DMWARN("couldn't allocate clean bitset");
445 			kfree(lc);
446 			return -ENOMEM;
447 		}
448 		lc->disk_header = NULL;
449 	} else {
450 		lc->log_dev = dev;
451 		lc->log_dev_failed = 0;
452 		lc->header_location.bdev = lc->log_dev->bdev;
453 		lc->header_location.sector = 0;
454 
455 		/*
456 		 * Buffer holds both header and bitset.
457 		 */
458 		buf_size = dm_round_up((LOG_OFFSET << SECTOR_SHIFT) +
459 				       bitset_size, ti->limits.hardsect_size);
460 
461 		if (buf_size > dev->bdev->bd_inode->i_size) {
462 			DMWARN("log device %s too small: need %llu bytes",
463 				dev->name, (unsigned long long)buf_size);
464 			kfree(lc);
465 			return -EINVAL;
466 		}
467 
468 		lc->header_location.count = buf_size >> SECTOR_SHIFT;
469 
470 		lc->io_req.mem.type = DM_IO_VMA;
471 		lc->io_req.notify.fn = NULL;
472 		lc->io_req.client = dm_io_client_create(dm_div_up(buf_size,
473 								   PAGE_SIZE));
474 		if (IS_ERR(lc->io_req.client)) {
475 			r = PTR_ERR(lc->io_req.client);
476 			DMWARN("couldn't allocate disk io client");
477 			kfree(lc);
478 			return -ENOMEM;
479 		}
480 
481 		lc->disk_header = vmalloc(buf_size);
482 		if (!lc->disk_header) {
483 			DMWARN("couldn't allocate disk log buffer");
484 			dm_io_client_destroy(lc->io_req.client);
485 			kfree(lc);
486 			return -ENOMEM;
487 		}
488 
489 		lc->io_req.mem.ptr.vma = lc->disk_header;
490 		lc->clean_bits = (void *)lc->disk_header +
491 				 (LOG_OFFSET << SECTOR_SHIFT);
492 	}
493 
494 	memset(lc->clean_bits, -1, bitset_size);
495 
496 	lc->sync_bits = vmalloc(bitset_size);
497 	if (!lc->sync_bits) {
498 		DMWARN("couldn't allocate sync bitset");
499 		if (!dev)
500 			vfree(lc->clean_bits);
501 		else
502 			dm_io_client_destroy(lc->io_req.client);
503 		vfree(lc->disk_header);
504 		kfree(lc);
505 		return -ENOMEM;
506 	}
507 	memset(lc->sync_bits, (sync == NOSYNC) ? -1 : 0, bitset_size);
508 	lc->sync_count = (sync == NOSYNC) ? region_count : 0;
509 
510 	lc->recovering_bits = vmalloc(bitset_size);
511 	if (!lc->recovering_bits) {
512 		DMWARN("couldn't allocate sync bitset");
513 		vfree(lc->sync_bits);
514 		if (!dev)
515 			vfree(lc->clean_bits);
516 		else
517 			dm_io_client_destroy(lc->io_req.client);
518 		vfree(lc->disk_header);
519 		kfree(lc);
520 		return -ENOMEM;
521 	}
522 	memset(lc->recovering_bits, 0, bitset_size);
523 	lc->sync_search = 0;
524 	log->context = lc;
525 
526 	return 0;
527 }
528 
529 static int core_ctr(struct dm_dirty_log *log, struct dm_target *ti,
530 		    unsigned int argc, char **argv)
531 {
532 	return create_log_context(log, ti, argc, argv, NULL);
533 }
534 
535 static void destroy_log_context(struct log_c *lc)
536 {
537 	vfree(lc->sync_bits);
538 	vfree(lc->recovering_bits);
539 	kfree(lc);
540 }
541 
542 static void core_dtr(struct dm_dirty_log *log)
543 {
544 	struct log_c *lc = (struct log_c *) log->context;
545 
546 	vfree(lc->clean_bits);
547 	destroy_log_context(lc);
548 }
549 
550 /*----------------------------------------------------------------
551  * disk log constructor/destructor
552  *
553  * argv contains log_device region_size followed optionally by [no]sync
554  *--------------------------------------------------------------*/
555 static int disk_ctr(struct dm_dirty_log *log, struct dm_target *ti,
556 		    unsigned int argc, char **argv)
557 {
558 	int r;
559 	struct dm_dev *dev;
560 
561 	if (argc < 2 || argc > 3) {
562 		DMWARN("wrong number of arguments to disk dirty region log");
563 		return -EINVAL;
564 	}
565 
566 	r = dm_get_device(ti, argv[0], 0, 0 /* FIXME */,
567 			  FMODE_READ | FMODE_WRITE, &dev);
568 	if (r)
569 		return r;
570 
571 	r = create_log_context(log, ti, argc - 1, argv + 1, dev);
572 	if (r) {
573 		dm_put_device(ti, dev);
574 		return r;
575 	}
576 
577 	return 0;
578 }
579 
580 static void disk_dtr(struct dm_dirty_log *log)
581 {
582 	struct log_c *lc = (struct log_c *) log->context;
583 
584 	dm_put_device(lc->ti, lc->log_dev);
585 	vfree(lc->disk_header);
586 	dm_io_client_destroy(lc->io_req.client);
587 	destroy_log_context(lc);
588 }
589 
590 static int count_bits32(uint32_t *addr, unsigned size)
591 {
592 	int count = 0, i;
593 
594 	for (i = 0; i < size; i++) {
595 		count += hweight32(*(addr+i));
596 	}
597 	return count;
598 }
599 
600 static void fail_log_device(struct log_c *lc)
601 {
602 	if (lc->log_dev_failed)
603 		return;
604 
605 	lc->log_dev_failed = 1;
606 	dm_table_event(lc->ti->table);
607 }
608 
609 static int disk_resume(struct dm_dirty_log *log)
610 {
611 	int r;
612 	unsigned i;
613 	struct log_c *lc = (struct log_c *) log->context;
614 	size_t size = lc->bitset_uint32_count * sizeof(uint32_t);
615 
616 	/* read the disk header */
617 	r = read_header(lc);
618 	if (r) {
619 		DMWARN("%s: Failed to read header on dirty region log device",
620 		       lc->log_dev->name);
621 		fail_log_device(lc);
622 		/*
623 		 * If the log device cannot be read, we must assume
624 		 * all regions are out-of-sync.  If we simply return
625 		 * here, the state will be uninitialized and could
626 		 * lead us to return 'in-sync' status for regions
627 		 * that are actually 'out-of-sync'.
628 		 */
629 		lc->header.nr_regions = 0;
630 	}
631 
632 	/* set or clear any new bits -- device has grown */
633 	if (lc->sync == NOSYNC)
634 		for (i = lc->header.nr_regions; i < lc->region_count; i++)
635 			/* FIXME: amazingly inefficient */
636 			log_set_bit(lc, lc->clean_bits, i);
637 	else
638 		for (i = lc->header.nr_regions; i < lc->region_count; i++)
639 			/* FIXME: amazingly inefficient */
640 			log_clear_bit(lc, lc->clean_bits, i);
641 
642 	/* clear any old bits -- device has shrunk */
643 	for (i = lc->region_count; i % (sizeof(*lc->clean_bits) << BYTE_SHIFT); i++)
644 		log_clear_bit(lc, lc->clean_bits, i);
645 
646 	/* copy clean across to sync */
647 	memcpy(lc->sync_bits, lc->clean_bits, size);
648 	lc->sync_count = count_bits32(lc->clean_bits, lc->bitset_uint32_count);
649 	lc->sync_search = 0;
650 
651 	/* set the correct number of regions in the header */
652 	lc->header.nr_regions = lc->region_count;
653 
654 	header_to_disk(&lc->header, lc->disk_header);
655 
656 	/* write the new header */
657 	r = rw_header(lc, WRITE);
658 	if (r) {
659 		DMWARN("%s: Failed to write header on dirty region log device",
660 		       lc->log_dev->name);
661 		fail_log_device(lc);
662 	}
663 
664 	return r;
665 }
666 
667 static uint32_t core_get_region_size(struct dm_dirty_log *log)
668 {
669 	struct log_c *lc = (struct log_c *) log->context;
670 	return lc->region_size;
671 }
672 
673 static int core_resume(struct dm_dirty_log *log)
674 {
675 	struct log_c *lc = (struct log_c *) log->context;
676 	lc->sync_search = 0;
677 	return 0;
678 }
679 
680 static int core_is_clean(struct dm_dirty_log *log, region_t region)
681 {
682 	struct log_c *lc = (struct log_c *) log->context;
683 	return log_test_bit(lc->clean_bits, region);
684 }
685 
686 static int core_in_sync(struct dm_dirty_log *log, region_t region, int block)
687 {
688 	struct log_c *lc = (struct log_c *) log->context;
689 	return log_test_bit(lc->sync_bits, region);
690 }
691 
692 static int core_flush(struct dm_dirty_log *log)
693 {
694 	/* no op */
695 	return 0;
696 }
697 
698 static int disk_flush(struct dm_dirty_log *log)
699 {
700 	int r;
701 	struct log_c *lc = (struct log_c *) log->context;
702 
703 	/* only write if the log has changed */
704 	if (!lc->touched)
705 		return 0;
706 
707 	r = rw_header(lc, WRITE);
708 	if (r)
709 		fail_log_device(lc);
710 	else
711 		lc->touched = 0;
712 
713 	return r;
714 }
715 
716 static void core_mark_region(struct dm_dirty_log *log, region_t region)
717 {
718 	struct log_c *lc = (struct log_c *) log->context;
719 	log_clear_bit(lc, lc->clean_bits, region);
720 }
721 
722 static void core_clear_region(struct dm_dirty_log *log, region_t region)
723 {
724 	struct log_c *lc = (struct log_c *) log->context;
725 	log_set_bit(lc, lc->clean_bits, region);
726 }
727 
728 static int core_get_resync_work(struct dm_dirty_log *log, region_t *region)
729 {
730 	struct log_c *lc = (struct log_c *) log->context;
731 
732 	if (lc->sync_search >= lc->region_count)
733 		return 0;
734 
735 	do {
736 		*region = ext2_find_next_zero_bit(
737 					     (unsigned long *) lc->sync_bits,
738 					     lc->region_count,
739 					     lc->sync_search);
740 		lc->sync_search = *region + 1;
741 
742 		if (*region >= lc->region_count)
743 			return 0;
744 
745 	} while (log_test_bit(lc->recovering_bits, *region));
746 
747 	log_set_bit(lc, lc->recovering_bits, *region);
748 	return 1;
749 }
750 
751 static void core_set_region_sync(struct dm_dirty_log *log, region_t region,
752 				 int in_sync)
753 {
754 	struct log_c *lc = (struct log_c *) log->context;
755 
756 	log_clear_bit(lc, lc->recovering_bits, region);
757 	if (in_sync) {
758 		log_set_bit(lc, lc->sync_bits, region);
759                 lc->sync_count++;
760         } else if (log_test_bit(lc->sync_bits, region)) {
761 		lc->sync_count--;
762 		log_clear_bit(lc, lc->sync_bits, region);
763 	}
764 }
765 
766 static region_t core_get_sync_count(struct dm_dirty_log *log)
767 {
768         struct log_c *lc = (struct log_c *) log->context;
769 
770         return lc->sync_count;
771 }
772 
773 #define	DMEMIT_SYNC \
774 	if (lc->sync != DEFAULTSYNC) \
775 		DMEMIT("%ssync ", lc->sync == NOSYNC ? "no" : "")
776 
777 static int core_status(struct dm_dirty_log *log, status_type_t status,
778 		       char *result, unsigned int maxlen)
779 {
780 	int sz = 0;
781 	struct log_c *lc = log->context;
782 
783 	switch(status) {
784 	case STATUSTYPE_INFO:
785 		DMEMIT("1 %s", log->type->name);
786 		break;
787 
788 	case STATUSTYPE_TABLE:
789 		DMEMIT("%s %u %u ", log->type->name,
790 		       lc->sync == DEFAULTSYNC ? 1 : 2, lc->region_size);
791 		DMEMIT_SYNC;
792 	}
793 
794 	return sz;
795 }
796 
797 static int disk_status(struct dm_dirty_log *log, status_type_t status,
798 		       char *result, unsigned int maxlen)
799 {
800 	int sz = 0;
801 	struct log_c *lc = log->context;
802 
803 	switch(status) {
804 	case STATUSTYPE_INFO:
805 		DMEMIT("3 %s %s %c", log->type->name, lc->log_dev->name,
806 		       lc->log_dev_failed ? 'D' : 'A');
807 		break;
808 
809 	case STATUSTYPE_TABLE:
810 		DMEMIT("%s %u %s %u ", log->type->name,
811 		       lc->sync == DEFAULTSYNC ? 2 : 3, lc->log_dev->name,
812 		       lc->region_size);
813 		DMEMIT_SYNC;
814 	}
815 
816 	return sz;
817 }
818 
819 static struct dm_dirty_log_type _core_type = {
820 	.name = "core",
821 	.module = THIS_MODULE,
822 	.ctr = core_ctr,
823 	.dtr = core_dtr,
824 	.resume = core_resume,
825 	.get_region_size = core_get_region_size,
826 	.is_clean = core_is_clean,
827 	.in_sync = core_in_sync,
828 	.flush = core_flush,
829 	.mark_region = core_mark_region,
830 	.clear_region = core_clear_region,
831 	.get_resync_work = core_get_resync_work,
832 	.set_region_sync = core_set_region_sync,
833 	.get_sync_count = core_get_sync_count,
834 	.status = core_status,
835 };
836 
837 static struct dm_dirty_log_type _disk_type = {
838 	.name = "disk",
839 	.module = THIS_MODULE,
840 	.ctr = disk_ctr,
841 	.dtr = disk_dtr,
842 	.postsuspend = disk_flush,
843 	.resume = disk_resume,
844 	.get_region_size = core_get_region_size,
845 	.is_clean = core_is_clean,
846 	.in_sync = core_in_sync,
847 	.flush = disk_flush,
848 	.mark_region = core_mark_region,
849 	.clear_region = core_clear_region,
850 	.get_resync_work = core_get_resync_work,
851 	.set_region_sync = core_set_region_sync,
852 	.get_sync_count = core_get_sync_count,
853 	.status = disk_status,
854 };
855 
856 static int __init dm_dirty_log_init(void)
857 {
858 	int r;
859 
860 	r = dm_dirty_log_type_register(&_core_type);
861 	if (r)
862 		DMWARN("couldn't register core log");
863 
864 	r = dm_dirty_log_type_register(&_disk_type);
865 	if (r) {
866 		DMWARN("couldn't register disk type");
867 		dm_dirty_log_type_unregister(&_core_type);
868 	}
869 
870 	return r;
871 }
872 
873 static void __exit dm_dirty_log_exit(void)
874 {
875 	dm_dirty_log_type_unregister(&_disk_type);
876 	dm_dirty_log_type_unregister(&_core_type);
877 }
878 
879 module_init(dm_dirty_log_init);
880 module_exit(dm_dirty_log_exit);
881 
882 MODULE_DESCRIPTION(DM_NAME " dirty region log");
883 MODULE_AUTHOR("Joe Thornber, Heinz Mauelshagen <dm-devel@redhat.com>");
884 MODULE_LICENSE("GPL");
885