xref: /openbmc/linux/drivers/md/dm-log.c (revision 1f012283)
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 static LIST_HEAD(_log_types);
20 static DEFINE_SPINLOCK(_lock);
21 
22 static struct dm_dirty_log_type *__find_dirty_log_type(const char *name)
23 {
24 	struct dm_dirty_log_type *log_type;
25 
26 	list_for_each_entry(log_type, &_log_types, list)
27 		if (!strcmp(name, log_type->name))
28 			return log_type;
29 
30 	return NULL;
31 }
32 
33 static struct dm_dirty_log_type *_get_dirty_log_type(const char *name)
34 {
35 	struct dm_dirty_log_type *log_type;
36 
37 	spin_lock(&_lock);
38 
39 	log_type = __find_dirty_log_type(name);
40 	if (log_type && !try_module_get(log_type->module))
41 		log_type = NULL;
42 
43 	spin_unlock(&_lock);
44 
45 	return log_type;
46 }
47 
48 /*
49  * get_type
50  * @type_name
51  *
52  * Attempt to retrieve the dm_dirty_log_type by name.  If not already
53  * available, attempt to load the appropriate module.
54  *
55  * Log modules are named "dm-log-" followed by the 'type_name'.
56  * Modules may contain multiple types.
57  * This function will first try the module "dm-log-<type_name>",
58  * then truncate 'type_name' on the last '-' and try again.
59  *
60  * For example, if type_name was "clustered-disk", it would search
61  * 'dm-log-clustered-disk' then 'dm-log-clustered'.
62  *
63  * Returns: dirty_log_type* on success, NULL on failure
64  */
65 static struct dm_dirty_log_type *get_type(const char *type_name)
66 {
67 	char *p, *type_name_dup;
68 	struct dm_dirty_log_type *log_type;
69 
70 	if (!type_name)
71 		return NULL;
72 
73 	log_type = _get_dirty_log_type(type_name);
74 	if (log_type)
75 		return log_type;
76 
77 	type_name_dup = kstrdup(type_name, GFP_KERNEL);
78 	if (!type_name_dup) {
79 		DMWARN("No memory left to attempt log module load for \"%s\"",
80 		       type_name);
81 		return NULL;
82 	}
83 
84 	while (request_module("dm-log-%s", type_name_dup) ||
85 	       !(log_type = _get_dirty_log_type(type_name))) {
86 		p = strrchr(type_name_dup, '-');
87 		if (!p)
88 			break;
89 		p[0] = '\0';
90 	}
91 
92 	if (!log_type)
93 		DMWARN("Module for logging type \"%s\" not found.", type_name);
94 
95 	kfree(type_name_dup);
96 
97 	return log_type;
98 }
99 
100 static void put_type(struct dm_dirty_log_type *type)
101 {
102 	if (!type)
103 		return;
104 
105 	spin_lock(&_lock);
106 	if (!__find_dirty_log_type(type->name))
107 		goto out;
108 
109 	module_put(type->module);
110 
111 out:
112 	spin_unlock(&_lock);
113 }
114 
115 int dm_dirty_log_type_register(struct dm_dirty_log_type *type)
116 {
117 	int r = 0;
118 
119 	spin_lock(&_lock);
120 	if (!__find_dirty_log_type(type->name))
121 		list_add(&type->list, &_log_types);
122 	else
123 		r = -EEXIST;
124 	spin_unlock(&_lock);
125 
126 	return r;
127 }
128 EXPORT_SYMBOL(dm_dirty_log_type_register);
129 
130 int dm_dirty_log_type_unregister(struct dm_dirty_log_type *type)
131 {
132 	spin_lock(&_lock);
133 
134 	if (!__find_dirty_log_type(type->name)) {
135 		spin_unlock(&_lock);
136 		return -EINVAL;
137 	}
138 
139 	list_del(&type->list);
140 
141 	spin_unlock(&_lock);
142 
143 	return 0;
144 }
145 EXPORT_SYMBOL(dm_dirty_log_type_unregister);
146 
147 struct dm_dirty_log *dm_dirty_log_create(const char *type_name,
148 			struct dm_target *ti,
149 			int (*flush_callback_fn)(struct dm_target *ti),
150 			unsigned int argc, char **argv)
151 {
152 	struct dm_dirty_log_type *type;
153 	struct dm_dirty_log *log;
154 
155 	log = kmalloc(sizeof(*log), GFP_KERNEL);
156 	if (!log)
157 		return NULL;
158 
159 	type = get_type(type_name);
160 	if (!type) {
161 		kfree(log);
162 		return NULL;
163 	}
164 
165 	log->flush_callback_fn = flush_callback_fn;
166 	log->type = type;
167 	if (type->ctr(log, ti, argc, argv)) {
168 		kfree(log);
169 		put_type(type);
170 		return NULL;
171 	}
172 
173 	return log;
174 }
175 EXPORT_SYMBOL(dm_dirty_log_create);
176 
177 void dm_dirty_log_destroy(struct dm_dirty_log *log)
178 {
179 	log->type->dtr(log);
180 	put_type(log->type);
181 	kfree(log);
182 }
183 EXPORT_SYMBOL(dm_dirty_log_destroy);
184 
185 /*-----------------------------------------------------------------
186  * Persistent and core logs share a lot of their implementation.
187  * FIXME: need a reload method to be called from a resume
188  *---------------------------------------------------------------*/
189 /*
190  * Magic for persistent mirrors: "MiRr"
191  */
192 #define MIRROR_MAGIC 0x4D695272
193 
194 /*
195  * The on-disk version of the metadata.
196  */
197 #define MIRROR_DISK_VERSION 2
198 #define LOG_OFFSET 2
199 
200 struct log_header_disk {
201 	__le32 magic;
202 
203 	/*
204 	 * Simple, incrementing version. no backward
205 	 * compatibility.
206 	 */
207 	__le32 version;
208 	__le64 nr_regions;
209 } __packed;
210 
211 struct log_header_core {
212 	uint32_t magic;
213 	uint32_t version;
214 	uint64_t nr_regions;
215 };
216 
217 struct log_c {
218 	struct dm_target *ti;
219 	int touched_dirtied;
220 	int touched_cleaned;
221 	int flush_failed;
222 	uint32_t region_size;
223 	unsigned int region_count;
224 	region_t sync_count;
225 
226 	unsigned bitset_uint32_count;
227 	uint32_t *clean_bits;
228 	uint32_t *sync_bits;
229 	uint32_t *recovering_bits;	/* FIXME: this seems excessive */
230 
231 	int sync_search;
232 
233 	/* Resync flag */
234 	enum sync {
235 		DEFAULTSYNC,	/* Synchronize if necessary */
236 		NOSYNC,		/* Devices known to be already in sync */
237 		FORCESYNC,	/* Force a sync to happen */
238 	} sync;
239 
240 	struct dm_io_request io_req;
241 
242 	/*
243 	 * Disk log fields
244 	 */
245 	int log_dev_failed;
246 	int log_dev_flush_failed;
247 	struct dm_dev *log_dev;
248 	struct log_header_core header;
249 
250 	struct dm_io_region header_location;
251 	struct log_header_disk *disk_header;
252 };
253 
254 /*
255  * The touched member needs to be updated every time we access
256  * one of the bitsets.
257  */
258 static inline int log_test_bit(uint32_t *bs, unsigned bit)
259 {
260 	return test_bit_le(bit, bs) ? 1 : 0;
261 }
262 
263 static inline void log_set_bit(struct log_c *l,
264 			       uint32_t *bs, unsigned bit)
265 {
266 	__set_bit_le(bit, bs);
267 	l->touched_cleaned = 1;
268 }
269 
270 static inline void log_clear_bit(struct log_c *l,
271 				 uint32_t *bs, unsigned bit)
272 {
273 	__clear_bit_le(bit, bs);
274 	l->touched_dirtied = 1;
275 }
276 
277 /*----------------------------------------------------------------
278  * Header IO
279  *--------------------------------------------------------------*/
280 static void header_to_disk(struct log_header_core *core, struct log_header_disk *disk)
281 {
282 	disk->magic = cpu_to_le32(core->magic);
283 	disk->version = cpu_to_le32(core->version);
284 	disk->nr_regions = cpu_to_le64(core->nr_regions);
285 }
286 
287 static void header_from_disk(struct log_header_core *core, struct log_header_disk *disk)
288 {
289 	core->magic = le32_to_cpu(disk->magic);
290 	core->version = le32_to_cpu(disk->version);
291 	core->nr_regions = le64_to_cpu(disk->nr_regions);
292 }
293 
294 static int rw_header(struct log_c *lc, int op)
295 {
296 	lc->io_req.bi_op = op;
297 	lc->io_req.bi_op_flags = 0;
298 
299 	return dm_io(&lc->io_req, 1, &lc->header_location, NULL);
300 }
301 
302 static int flush_header(struct log_c *lc)
303 {
304 	struct dm_io_region null_location = {
305 		.bdev = lc->header_location.bdev,
306 		.sector = 0,
307 		.count = 0,
308 	};
309 
310 	lc->io_req.bi_op = REQ_OP_WRITE;
311 	lc->io_req.bi_op_flags = REQ_PREFLUSH;
312 
313 	return dm_io(&lc->io_req, 1, &null_location, NULL);
314 }
315 
316 static int read_header(struct log_c *log)
317 {
318 	int r;
319 
320 	r = rw_header(log, REQ_OP_READ);
321 	if (r)
322 		return r;
323 
324 	header_from_disk(&log->header, log->disk_header);
325 
326 	/* New log required? */
327 	if (log->sync != DEFAULTSYNC || log->header.magic != MIRROR_MAGIC) {
328 		log->header.magic = MIRROR_MAGIC;
329 		log->header.version = MIRROR_DISK_VERSION;
330 		log->header.nr_regions = 0;
331 	}
332 
333 #ifdef __LITTLE_ENDIAN
334 	if (log->header.version == 1)
335 		log->header.version = 2;
336 #endif
337 
338 	if (log->header.version != MIRROR_DISK_VERSION) {
339 		DMWARN("incompatible disk log version");
340 		return -EINVAL;
341 	}
342 
343 	return 0;
344 }
345 
346 static int _check_region_size(struct dm_target *ti, uint32_t region_size)
347 {
348 	if (region_size < 2 || region_size > ti->len)
349 		return 0;
350 
351 	if (!is_power_of_2(region_size))
352 		return 0;
353 
354 	return 1;
355 }
356 
357 /*----------------------------------------------------------------
358  * core log constructor/destructor
359  *
360  * argv contains region_size followed optionally by [no]sync
361  *--------------------------------------------------------------*/
362 #define BYTE_SHIFT 3
363 static int create_log_context(struct dm_dirty_log *log, struct dm_target *ti,
364 			      unsigned int argc, char **argv,
365 			      struct dm_dev *dev)
366 {
367 	enum sync sync = DEFAULTSYNC;
368 
369 	struct log_c *lc;
370 	uint32_t region_size;
371 	unsigned int region_count;
372 	size_t bitset_size, buf_size;
373 	int r;
374 	char dummy;
375 
376 	if (argc < 1 || argc > 2) {
377 		DMWARN("wrong number of arguments to dirty region log");
378 		return -EINVAL;
379 	}
380 
381 	if (argc > 1) {
382 		if (!strcmp(argv[1], "sync"))
383 			sync = FORCESYNC;
384 		else if (!strcmp(argv[1], "nosync"))
385 			sync = NOSYNC;
386 		else {
387 			DMWARN("unrecognised sync argument to "
388 			       "dirty region log: %s", argv[1]);
389 			return -EINVAL;
390 		}
391 	}
392 
393 	if (sscanf(argv[0], "%u%c", &region_size, &dummy) != 1 ||
394 	    !_check_region_size(ti, region_size)) {
395 		DMWARN("invalid region size %s", argv[0]);
396 		return -EINVAL;
397 	}
398 
399 	region_count = dm_sector_div_up(ti->len, region_size);
400 
401 	lc = kmalloc(sizeof(*lc), GFP_KERNEL);
402 	if (!lc) {
403 		DMWARN("couldn't allocate core log");
404 		return -ENOMEM;
405 	}
406 
407 	lc->ti = ti;
408 	lc->touched_dirtied = 0;
409 	lc->touched_cleaned = 0;
410 	lc->flush_failed = 0;
411 	lc->region_size = region_size;
412 	lc->region_count = region_count;
413 	lc->sync = sync;
414 
415 	/*
416 	 * Work out how many "unsigned long"s we need to hold the bitset.
417 	 */
418 	bitset_size = dm_round_up(region_count,
419 				  sizeof(*lc->clean_bits) << BYTE_SHIFT);
420 	bitset_size >>= BYTE_SHIFT;
421 
422 	lc->bitset_uint32_count = bitset_size / sizeof(*lc->clean_bits);
423 
424 	/*
425 	 * Disk log?
426 	 */
427 	if (!dev) {
428 		lc->clean_bits = vmalloc(bitset_size);
429 		if (!lc->clean_bits) {
430 			DMWARN("couldn't allocate clean bitset");
431 			kfree(lc);
432 			return -ENOMEM;
433 		}
434 		lc->disk_header = NULL;
435 	} else {
436 		lc->log_dev = dev;
437 		lc->log_dev_failed = 0;
438 		lc->log_dev_flush_failed = 0;
439 		lc->header_location.bdev = lc->log_dev->bdev;
440 		lc->header_location.sector = 0;
441 
442 		/*
443 		 * Buffer holds both header and bitset.
444 		 */
445 		buf_size =
446 		    dm_round_up((LOG_OFFSET << SECTOR_SHIFT) + bitset_size,
447 				bdev_logical_block_size(lc->header_location.
448 							    bdev));
449 
450 		if (buf_size > bdev_nr_bytes(dev->bdev)) {
451 			DMWARN("log device %s too small: need %llu bytes",
452 				dev->name, (unsigned long long)buf_size);
453 			kfree(lc);
454 			return -EINVAL;
455 		}
456 
457 		lc->header_location.count = buf_size >> SECTOR_SHIFT;
458 
459 		lc->io_req.mem.type = DM_IO_VMA;
460 		lc->io_req.notify.fn = NULL;
461 		lc->io_req.client = dm_io_client_create();
462 		if (IS_ERR(lc->io_req.client)) {
463 			r = PTR_ERR(lc->io_req.client);
464 			DMWARN("couldn't allocate disk io client");
465 			kfree(lc);
466 			return r;
467 		}
468 
469 		lc->disk_header = vmalloc(buf_size);
470 		if (!lc->disk_header) {
471 			DMWARN("couldn't allocate disk log buffer");
472 			dm_io_client_destroy(lc->io_req.client);
473 			kfree(lc);
474 			return -ENOMEM;
475 		}
476 
477 		lc->io_req.mem.ptr.vma = lc->disk_header;
478 		lc->clean_bits = (void *)lc->disk_header +
479 				 (LOG_OFFSET << SECTOR_SHIFT);
480 	}
481 
482 	memset(lc->clean_bits, -1, bitset_size);
483 
484 	lc->sync_bits = vmalloc(bitset_size);
485 	if (!lc->sync_bits) {
486 		DMWARN("couldn't allocate sync bitset");
487 		if (!dev)
488 			vfree(lc->clean_bits);
489 		else
490 			dm_io_client_destroy(lc->io_req.client);
491 		vfree(lc->disk_header);
492 		kfree(lc);
493 		return -ENOMEM;
494 	}
495 	memset(lc->sync_bits, (sync == NOSYNC) ? -1 : 0, bitset_size);
496 	lc->sync_count = (sync == NOSYNC) ? region_count : 0;
497 
498 	lc->recovering_bits = vzalloc(bitset_size);
499 	if (!lc->recovering_bits) {
500 		DMWARN("couldn't allocate sync bitset");
501 		vfree(lc->sync_bits);
502 		if (!dev)
503 			vfree(lc->clean_bits);
504 		else
505 			dm_io_client_destroy(lc->io_req.client);
506 		vfree(lc->disk_header);
507 		kfree(lc);
508 		return -ENOMEM;
509 	}
510 	lc->sync_search = 0;
511 	log->context = lc;
512 
513 	return 0;
514 }
515 
516 static int core_ctr(struct dm_dirty_log *log, struct dm_target *ti,
517 		    unsigned int argc, char **argv)
518 {
519 	return create_log_context(log, ti, argc, argv, NULL);
520 }
521 
522 static void destroy_log_context(struct log_c *lc)
523 {
524 	vfree(lc->sync_bits);
525 	vfree(lc->recovering_bits);
526 	kfree(lc);
527 }
528 
529 static void core_dtr(struct dm_dirty_log *log)
530 {
531 	struct log_c *lc = (struct log_c *) log->context;
532 
533 	vfree(lc->clean_bits);
534 	destroy_log_context(lc);
535 }
536 
537 /*----------------------------------------------------------------
538  * disk log constructor/destructor
539  *
540  * argv contains log_device region_size followed optionally by [no]sync
541  *--------------------------------------------------------------*/
542 static int disk_ctr(struct dm_dirty_log *log, struct dm_target *ti,
543 		    unsigned int argc, char **argv)
544 {
545 	int r;
546 	struct dm_dev *dev;
547 
548 	if (argc < 2 || argc > 3) {
549 		DMWARN("wrong number of arguments to disk dirty region log");
550 		return -EINVAL;
551 	}
552 
553 	r = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &dev);
554 	if (r)
555 		return r;
556 
557 	r = create_log_context(log, ti, argc - 1, argv + 1, dev);
558 	if (r) {
559 		dm_put_device(ti, dev);
560 		return r;
561 	}
562 
563 	return 0;
564 }
565 
566 static void disk_dtr(struct dm_dirty_log *log)
567 {
568 	struct log_c *lc = (struct log_c *) log->context;
569 
570 	dm_put_device(lc->ti, lc->log_dev);
571 	vfree(lc->disk_header);
572 	dm_io_client_destroy(lc->io_req.client);
573 	destroy_log_context(lc);
574 }
575 
576 static void fail_log_device(struct log_c *lc)
577 {
578 	if (lc->log_dev_failed)
579 		return;
580 
581 	lc->log_dev_failed = 1;
582 	dm_table_event(lc->ti->table);
583 }
584 
585 static int disk_resume(struct dm_dirty_log *log)
586 {
587 	int r;
588 	unsigned i;
589 	struct log_c *lc = (struct log_c *) log->context;
590 	size_t size = lc->bitset_uint32_count * sizeof(uint32_t);
591 
592 	/* read the disk header */
593 	r = read_header(lc);
594 	if (r) {
595 		DMWARN("%s: Failed to read header on dirty region log device",
596 		       lc->log_dev->name);
597 		fail_log_device(lc);
598 		/*
599 		 * If the log device cannot be read, we must assume
600 		 * all regions are out-of-sync.  If we simply return
601 		 * here, the state will be uninitialized and could
602 		 * lead us to return 'in-sync' status for regions
603 		 * that are actually 'out-of-sync'.
604 		 */
605 		lc->header.nr_regions = 0;
606 	}
607 
608 	/* set or clear any new bits -- device has grown */
609 	if (lc->sync == NOSYNC)
610 		for (i = lc->header.nr_regions; i < lc->region_count; i++)
611 			/* FIXME: amazingly inefficient */
612 			log_set_bit(lc, lc->clean_bits, i);
613 	else
614 		for (i = lc->header.nr_regions; i < lc->region_count; i++)
615 			/* FIXME: amazingly inefficient */
616 			log_clear_bit(lc, lc->clean_bits, i);
617 
618 	/* clear any old bits -- device has shrunk */
619 	for (i = lc->region_count; i % (sizeof(*lc->clean_bits) << BYTE_SHIFT); i++)
620 		log_clear_bit(lc, lc->clean_bits, i);
621 
622 	/* copy clean across to sync */
623 	memcpy(lc->sync_bits, lc->clean_bits, size);
624 	lc->sync_count = memweight(lc->clean_bits,
625 				lc->bitset_uint32_count * sizeof(uint32_t));
626 	lc->sync_search = 0;
627 
628 	/* set the correct number of regions in the header */
629 	lc->header.nr_regions = lc->region_count;
630 
631 	header_to_disk(&lc->header, lc->disk_header);
632 
633 	/* write the new header */
634 	r = rw_header(lc, REQ_OP_WRITE);
635 	if (!r) {
636 		r = flush_header(lc);
637 		if (r)
638 			lc->log_dev_flush_failed = 1;
639 	}
640 	if (r) {
641 		DMWARN("%s: Failed to write header on dirty region log device",
642 		       lc->log_dev->name);
643 		fail_log_device(lc);
644 	}
645 
646 	return r;
647 }
648 
649 static uint32_t core_get_region_size(struct dm_dirty_log *log)
650 {
651 	struct log_c *lc = (struct log_c *) log->context;
652 	return lc->region_size;
653 }
654 
655 static int core_resume(struct dm_dirty_log *log)
656 {
657 	struct log_c *lc = (struct log_c *) log->context;
658 	lc->sync_search = 0;
659 	return 0;
660 }
661 
662 static int core_is_clean(struct dm_dirty_log *log, region_t region)
663 {
664 	struct log_c *lc = (struct log_c *) log->context;
665 	return log_test_bit(lc->clean_bits, region);
666 }
667 
668 static int core_in_sync(struct dm_dirty_log *log, region_t region, int block)
669 {
670 	struct log_c *lc = (struct log_c *) log->context;
671 	return log_test_bit(lc->sync_bits, region);
672 }
673 
674 static int core_flush(struct dm_dirty_log *log)
675 {
676 	/* no op */
677 	return 0;
678 }
679 
680 static int disk_flush(struct dm_dirty_log *log)
681 {
682 	int r, i;
683 	struct log_c *lc = log->context;
684 
685 	/* only write if the log has changed */
686 	if (!lc->touched_cleaned && !lc->touched_dirtied)
687 		return 0;
688 
689 	if (lc->touched_cleaned && log->flush_callback_fn &&
690 	    log->flush_callback_fn(lc->ti)) {
691 		/*
692 		 * At this point it is impossible to determine which
693 		 * regions are clean and which are dirty (without
694 		 * re-reading the log off disk). So mark all of them
695 		 * dirty.
696 		 */
697 		lc->flush_failed = 1;
698 		for (i = 0; i < lc->region_count; i++)
699 			log_clear_bit(lc, lc->clean_bits, i);
700 	}
701 
702 	r = rw_header(lc, REQ_OP_WRITE);
703 	if (r)
704 		fail_log_device(lc);
705 	else {
706 		if (lc->touched_dirtied) {
707 			r = flush_header(lc);
708 			if (r) {
709 				lc->log_dev_flush_failed = 1;
710 				fail_log_device(lc);
711 			} else
712 				lc->touched_dirtied = 0;
713 		}
714 		lc->touched_cleaned = 0;
715 	}
716 
717 	return r;
718 }
719 
720 static void core_mark_region(struct dm_dirty_log *log, region_t region)
721 {
722 	struct log_c *lc = (struct log_c *) log->context;
723 	log_clear_bit(lc, lc->clean_bits, region);
724 }
725 
726 static void core_clear_region(struct dm_dirty_log *log, region_t region)
727 {
728 	struct log_c *lc = (struct log_c *) log->context;
729 	if (likely(!lc->flush_failed))
730 		log_set_bit(lc, lc->clean_bits, region);
731 }
732 
733 static int core_get_resync_work(struct dm_dirty_log *log, region_t *region)
734 {
735 	struct log_c *lc = (struct log_c *) log->context;
736 
737 	if (lc->sync_search >= lc->region_count)
738 		return 0;
739 
740 	do {
741 		*region = find_next_zero_bit_le(lc->sync_bits,
742 					     lc->region_count,
743 					     lc->sync_search);
744 		lc->sync_search = *region + 1;
745 
746 		if (*region >= lc->region_count)
747 			return 0;
748 
749 	} while (log_test_bit(lc->recovering_bits, *region));
750 
751 	log_set_bit(lc, lc->recovering_bits, *region);
752 	return 1;
753 }
754 
755 static void core_set_region_sync(struct dm_dirty_log *log, region_t region,
756 				 int in_sync)
757 {
758 	struct log_c *lc = (struct log_c *) log->context;
759 
760 	log_clear_bit(lc, lc->recovering_bits, region);
761 	if (in_sync) {
762 		log_set_bit(lc, lc->sync_bits, region);
763                 lc->sync_count++;
764         } else if (log_test_bit(lc->sync_bits, region)) {
765 		lc->sync_count--;
766 		log_clear_bit(lc, lc->sync_bits, region);
767 	}
768 }
769 
770 static region_t core_get_sync_count(struct dm_dirty_log *log)
771 {
772         struct log_c *lc = (struct log_c *) log->context;
773 
774         return lc->sync_count;
775 }
776 
777 #define	DMEMIT_SYNC \
778 	if (lc->sync != DEFAULTSYNC) \
779 		DMEMIT("%ssync ", lc->sync == NOSYNC ? "no" : "")
780 
781 static int core_status(struct dm_dirty_log *log, status_type_t status,
782 		       char *result, unsigned int maxlen)
783 {
784 	int sz = 0;
785 	struct log_c *lc = log->context;
786 
787 	switch(status) {
788 	case STATUSTYPE_INFO:
789 		DMEMIT("1 %s", log->type->name);
790 		break;
791 
792 	case STATUSTYPE_TABLE:
793 		DMEMIT("%s %u %u ", log->type->name,
794 		       lc->sync == DEFAULTSYNC ? 1 : 2, lc->region_size);
795 		DMEMIT_SYNC;
796 		break;
797 
798 	case STATUSTYPE_IMA:
799 		*result = '\0';
800 		break;
801 	}
802 
803 	return sz;
804 }
805 
806 static int disk_status(struct dm_dirty_log *log, status_type_t status,
807 		       char *result, unsigned int maxlen)
808 {
809 	int sz = 0;
810 	struct log_c *lc = log->context;
811 
812 	switch(status) {
813 	case STATUSTYPE_INFO:
814 		DMEMIT("3 %s %s %c", log->type->name, lc->log_dev->name,
815 		       lc->log_dev_flush_failed ? 'F' :
816 		       lc->log_dev_failed ? 'D' :
817 		       'A');
818 		break;
819 
820 	case STATUSTYPE_TABLE:
821 		DMEMIT("%s %u %s %u ", log->type->name,
822 		       lc->sync == DEFAULTSYNC ? 2 : 3, lc->log_dev->name,
823 		       lc->region_size);
824 		DMEMIT_SYNC;
825 		break;
826 
827 	case STATUSTYPE_IMA:
828 		*result = '\0';
829 		break;
830 	}
831 
832 	return sz;
833 }
834 
835 static struct dm_dirty_log_type _core_type = {
836 	.name = "core",
837 	.module = THIS_MODULE,
838 	.ctr = core_ctr,
839 	.dtr = core_dtr,
840 	.resume = core_resume,
841 	.get_region_size = core_get_region_size,
842 	.is_clean = core_is_clean,
843 	.in_sync = core_in_sync,
844 	.flush = core_flush,
845 	.mark_region = core_mark_region,
846 	.clear_region = core_clear_region,
847 	.get_resync_work = core_get_resync_work,
848 	.set_region_sync = core_set_region_sync,
849 	.get_sync_count = core_get_sync_count,
850 	.status = core_status,
851 };
852 
853 static struct dm_dirty_log_type _disk_type = {
854 	.name = "disk",
855 	.module = THIS_MODULE,
856 	.ctr = disk_ctr,
857 	.dtr = disk_dtr,
858 	.postsuspend = disk_flush,
859 	.resume = disk_resume,
860 	.get_region_size = core_get_region_size,
861 	.is_clean = core_is_clean,
862 	.in_sync = core_in_sync,
863 	.flush = disk_flush,
864 	.mark_region = core_mark_region,
865 	.clear_region = core_clear_region,
866 	.get_resync_work = core_get_resync_work,
867 	.set_region_sync = core_set_region_sync,
868 	.get_sync_count = core_get_sync_count,
869 	.status = disk_status,
870 };
871 
872 static int __init dm_dirty_log_init(void)
873 {
874 	int r;
875 
876 	r = dm_dirty_log_type_register(&_core_type);
877 	if (r)
878 		DMWARN("couldn't register core log");
879 
880 	r = dm_dirty_log_type_register(&_disk_type);
881 	if (r) {
882 		DMWARN("couldn't register disk type");
883 		dm_dirty_log_type_unregister(&_core_type);
884 	}
885 
886 	return r;
887 }
888 
889 static void __exit dm_dirty_log_exit(void)
890 {
891 	dm_dirty_log_type_unregister(&_disk_type);
892 	dm_dirty_log_type_unregister(&_core_type);
893 }
894 
895 module_init(dm_dirty_log_init);
896 module_exit(dm_dirty_log_exit);
897 
898 MODULE_DESCRIPTION(DM_NAME " dirty region log");
899 MODULE_AUTHOR("Joe Thornber, Heinz Mauelshagen <dm-devel@redhat.com>");
900 MODULE_LICENSE("GPL");
901