xref: /openbmc/linux/drivers/md/dm-log.c (revision 9c1f8594)
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 rw)
295 {
296 	lc->io_req.bi_rw = rw;
297 
298 	return dm_io(&lc->io_req, 1, &lc->header_location, NULL);
299 }
300 
301 static int flush_header(struct log_c *lc)
302 {
303 	struct dm_io_region null_location = {
304 		.bdev = lc->header_location.bdev,
305 		.sector = 0,
306 		.count = 0,
307 	};
308 
309 	lc->io_req.bi_rw = WRITE_FLUSH;
310 
311 	return dm_io(&lc->io_req, 1, &null_location, NULL);
312 }
313 
314 static int read_header(struct log_c *log)
315 {
316 	int r;
317 
318 	r = rw_header(log, READ);
319 	if (r)
320 		return r;
321 
322 	header_from_disk(&log->header, log->disk_header);
323 
324 	/* New log required? */
325 	if (log->sync != DEFAULTSYNC || log->header.magic != MIRROR_MAGIC) {
326 		log->header.magic = MIRROR_MAGIC;
327 		log->header.version = MIRROR_DISK_VERSION;
328 		log->header.nr_regions = 0;
329 	}
330 
331 #ifdef __LITTLE_ENDIAN
332 	if (log->header.version == 1)
333 		log->header.version = 2;
334 #endif
335 
336 	if (log->header.version != MIRROR_DISK_VERSION) {
337 		DMWARN("incompatible disk log version");
338 		return -EINVAL;
339 	}
340 
341 	return 0;
342 }
343 
344 static int _check_region_size(struct dm_target *ti, uint32_t region_size)
345 {
346 	if (region_size < 2 || region_size > ti->len)
347 		return 0;
348 
349 	if (!is_power_of_2(region_size))
350 		return 0;
351 
352 	return 1;
353 }
354 
355 /*----------------------------------------------------------------
356  * core log constructor/destructor
357  *
358  * argv contains region_size followed optionally by [no]sync
359  *--------------------------------------------------------------*/
360 #define BYTE_SHIFT 3
361 static int create_log_context(struct dm_dirty_log *log, struct dm_target *ti,
362 			      unsigned int argc, char **argv,
363 			      struct dm_dev *dev)
364 {
365 	enum sync sync = DEFAULTSYNC;
366 
367 	struct log_c *lc;
368 	uint32_t region_size;
369 	unsigned int region_count;
370 	size_t bitset_size, buf_size;
371 	int r;
372 
373 	if (argc < 1 || argc > 2) {
374 		DMWARN("wrong number of arguments to dirty region log");
375 		return -EINVAL;
376 	}
377 
378 	if (argc > 1) {
379 		if (!strcmp(argv[1], "sync"))
380 			sync = FORCESYNC;
381 		else if (!strcmp(argv[1], "nosync"))
382 			sync = NOSYNC;
383 		else {
384 			DMWARN("unrecognised sync argument to "
385 			       "dirty region log: %s", argv[1]);
386 			return -EINVAL;
387 		}
388 	}
389 
390 	if (sscanf(argv[0], "%u", &region_size) != 1 ||
391 	    !_check_region_size(ti, region_size)) {
392 		DMWARN("invalid region size %s", argv[0]);
393 		return -EINVAL;
394 	}
395 
396 	region_count = dm_sector_div_up(ti->len, region_size);
397 
398 	lc = kmalloc(sizeof(*lc), GFP_KERNEL);
399 	if (!lc) {
400 		DMWARN("couldn't allocate core log");
401 		return -ENOMEM;
402 	}
403 
404 	lc->ti = ti;
405 	lc->touched_dirtied = 0;
406 	lc->touched_cleaned = 0;
407 	lc->flush_failed = 0;
408 	lc->region_size = region_size;
409 	lc->region_count = region_count;
410 	lc->sync = sync;
411 
412 	/*
413 	 * Work out how many "unsigned long"s we need to hold the bitset.
414 	 */
415 	bitset_size = dm_round_up(region_count,
416 				  sizeof(*lc->clean_bits) << BYTE_SHIFT);
417 	bitset_size >>= BYTE_SHIFT;
418 
419 	lc->bitset_uint32_count = bitset_size / sizeof(*lc->clean_bits);
420 
421 	/*
422 	 * Disk log?
423 	 */
424 	if (!dev) {
425 		lc->clean_bits = vmalloc(bitset_size);
426 		if (!lc->clean_bits) {
427 			DMWARN("couldn't allocate clean bitset");
428 			kfree(lc);
429 			return -ENOMEM;
430 		}
431 		lc->disk_header = NULL;
432 	} else {
433 		lc->log_dev = dev;
434 		lc->log_dev_failed = 0;
435 		lc->log_dev_flush_failed = 0;
436 		lc->header_location.bdev = lc->log_dev->bdev;
437 		lc->header_location.sector = 0;
438 
439 		/*
440 		 * Buffer holds both header and bitset.
441 		 */
442 		buf_size =
443 		    dm_round_up((LOG_OFFSET << SECTOR_SHIFT) + bitset_size,
444 				bdev_logical_block_size(lc->header_location.
445 							    bdev));
446 
447 		if (buf_size > i_size_read(dev->bdev->bd_inode)) {
448 			DMWARN("log device %s too small: need %llu bytes",
449 				dev->name, (unsigned long long)buf_size);
450 			kfree(lc);
451 			return -EINVAL;
452 		}
453 
454 		lc->header_location.count = buf_size >> SECTOR_SHIFT;
455 
456 		lc->io_req.mem.type = DM_IO_VMA;
457 		lc->io_req.notify.fn = NULL;
458 		lc->io_req.client = dm_io_client_create();
459 		if (IS_ERR(lc->io_req.client)) {
460 			r = PTR_ERR(lc->io_req.client);
461 			DMWARN("couldn't allocate disk io client");
462 			kfree(lc);
463 			return r;
464 		}
465 
466 		lc->disk_header = vmalloc(buf_size);
467 		if (!lc->disk_header) {
468 			DMWARN("couldn't allocate disk log buffer");
469 			dm_io_client_destroy(lc->io_req.client);
470 			kfree(lc);
471 			return -ENOMEM;
472 		}
473 
474 		lc->io_req.mem.ptr.vma = lc->disk_header;
475 		lc->clean_bits = (void *)lc->disk_header +
476 				 (LOG_OFFSET << SECTOR_SHIFT);
477 	}
478 
479 	memset(lc->clean_bits, -1, bitset_size);
480 
481 	lc->sync_bits = vmalloc(bitset_size);
482 	if (!lc->sync_bits) {
483 		DMWARN("couldn't allocate sync bitset");
484 		if (!dev)
485 			vfree(lc->clean_bits);
486 		else
487 			dm_io_client_destroy(lc->io_req.client);
488 		vfree(lc->disk_header);
489 		kfree(lc);
490 		return -ENOMEM;
491 	}
492 	memset(lc->sync_bits, (sync == NOSYNC) ? -1 : 0, bitset_size);
493 	lc->sync_count = (sync == NOSYNC) ? region_count : 0;
494 
495 	lc->recovering_bits = vzalloc(bitset_size);
496 	if (!lc->recovering_bits) {
497 		DMWARN("couldn't allocate sync bitset");
498 		vfree(lc->sync_bits);
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 	lc->sync_search = 0;
508 	log->context = lc;
509 
510 	return 0;
511 }
512 
513 static int core_ctr(struct dm_dirty_log *log, struct dm_target *ti,
514 		    unsigned int argc, char **argv)
515 {
516 	return create_log_context(log, ti, argc, argv, NULL);
517 }
518 
519 static void destroy_log_context(struct log_c *lc)
520 {
521 	vfree(lc->sync_bits);
522 	vfree(lc->recovering_bits);
523 	kfree(lc);
524 }
525 
526 static void core_dtr(struct dm_dirty_log *log)
527 {
528 	struct log_c *lc = (struct log_c *) log->context;
529 
530 	vfree(lc->clean_bits);
531 	destroy_log_context(lc);
532 }
533 
534 /*----------------------------------------------------------------
535  * disk log constructor/destructor
536  *
537  * argv contains log_device region_size followed optionally by [no]sync
538  *--------------------------------------------------------------*/
539 static int disk_ctr(struct dm_dirty_log *log, struct dm_target *ti,
540 		    unsigned int argc, char **argv)
541 {
542 	int r;
543 	struct dm_dev *dev;
544 
545 	if (argc < 2 || argc > 3) {
546 		DMWARN("wrong number of arguments to disk dirty region log");
547 		return -EINVAL;
548 	}
549 
550 	r = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &dev);
551 	if (r)
552 		return r;
553 
554 	r = create_log_context(log, ti, argc - 1, argv + 1, dev);
555 	if (r) {
556 		dm_put_device(ti, dev);
557 		return r;
558 	}
559 
560 	return 0;
561 }
562 
563 static void disk_dtr(struct dm_dirty_log *log)
564 {
565 	struct log_c *lc = (struct log_c *) log->context;
566 
567 	dm_put_device(lc->ti, lc->log_dev);
568 	vfree(lc->disk_header);
569 	dm_io_client_destroy(lc->io_req.client);
570 	destroy_log_context(lc);
571 }
572 
573 static int count_bits32(uint32_t *addr, unsigned size)
574 {
575 	int count = 0, i;
576 
577 	for (i = 0; i < size; i++) {
578 		count += hweight32(*(addr+i));
579 	}
580 	return count;
581 }
582 
583 static void fail_log_device(struct log_c *lc)
584 {
585 	if (lc->log_dev_failed)
586 		return;
587 
588 	lc->log_dev_failed = 1;
589 	dm_table_event(lc->ti->table);
590 }
591 
592 static int disk_resume(struct dm_dirty_log *log)
593 {
594 	int r;
595 	unsigned i;
596 	struct log_c *lc = (struct log_c *) log->context;
597 	size_t size = lc->bitset_uint32_count * sizeof(uint32_t);
598 
599 	/* read the disk header */
600 	r = read_header(lc);
601 	if (r) {
602 		DMWARN("%s: Failed to read header on dirty region log device",
603 		       lc->log_dev->name);
604 		fail_log_device(lc);
605 		/*
606 		 * If the log device cannot be read, we must assume
607 		 * all regions are out-of-sync.  If we simply return
608 		 * here, the state will be uninitialized and could
609 		 * lead us to return 'in-sync' status for regions
610 		 * that are actually 'out-of-sync'.
611 		 */
612 		lc->header.nr_regions = 0;
613 	}
614 
615 	/* set or clear any new bits -- device has grown */
616 	if (lc->sync == NOSYNC)
617 		for (i = lc->header.nr_regions; i < lc->region_count; i++)
618 			/* FIXME: amazingly inefficient */
619 			log_set_bit(lc, lc->clean_bits, i);
620 	else
621 		for (i = lc->header.nr_regions; i < lc->region_count; i++)
622 			/* FIXME: amazingly inefficient */
623 			log_clear_bit(lc, lc->clean_bits, i);
624 
625 	/* clear any old bits -- device has shrunk */
626 	for (i = lc->region_count; i % (sizeof(*lc->clean_bits) << BYTE_SHIFT); i++)
627 		log_clear_bit(lc, lc->clean_bits, i);
628 
629 	/* copy clean across to sync */
630 	memcpy(lc->sync_bits, lc->clean_bits, size);
631 	lc->sync_count = count_bits32(lc->clean_bits, lc->bitset_uint32_count);
632 	lc->sync_search = 0;
633 
634 	/* set the correct number of regions in the header */
635 	lc->header.nr_regions = lc->region_count;
636 
637 	header_to_disk(&lc->header, lc->disk_header);
638 
639 	/* write the new header */
640 	r = rw_header(lc, WRITE);
641 	if (!r) {
642 		r = flush_header(lc);
643 		if (r)
644 			lc->log_dev_flush_failed = 1;
645 	}
646 	if (r) {
647 		DMWARN("%s: Failed to write header on dirty region log device",
648 		       lc->log_dev->name);
649 		fail_log_device(lc);
650 	}
651 
652 	return r;
653 }
654 
655 static uint32_t core_get_region_size(struct dm_dirty_log *log)
656 {
657 	struct log_c *lc = (struct log_c *) log->context;
658 	return lc->region_size;
659 }
660 
661 static int core_resume(struct dm_dirty_log *log)
662 {
663 	struct log_c *lc = (struct log_c *) log->context;
664 	lc->sync_search = 0;
665 	return 0;
666 }
667 
668 static int core_is_clean(struct dm_dirty_log *log, region_t region)
669 {
670 	struct log_c *lc = (struct log_c *) log->context;
671 	return log_test_bit(lc->clean_bits, region);
672 }
673 
674 static int core_in_sync(struct dm_dirty_log *log, region_t region, int block)
675 {
676 	struct log_c *lc = (struct log_c *) log->context;
677 	return log_test_bit(lc->sync_bits, region);
678 }
679 
680 static int core_flush(struct dm_dirty_log *log)
681 {
682 	/* no op */
683 	return 0;
684 }
685 
686 static int disk_flush(struct dm_dirty_log *log)
687 {
688 	int r, i;
689 	struct log_c *lc = log->context;
690 
691 	/* only write if the log has changed */
692 	if (!lc->touched_cleaned && !lc->touched_dirtied)
693 		return 0;
694 
695 	if (lc->touched_cleaned && log->flush_callback_fn &&
696 	    log->flush_callback_fn(lc->ti)) {
697 		/*
698 		 * At this point it is impossible to determine which
699 		 * regions are clean and which are dirty (without
700 		 * re-reading the log off disk). So mark all of them
701 		 * dirty.
702 		 */
703 		lc->flush_failed = 1;
704 		for (i = 0; i < lc->region_count; i++)
705 			log_clear_bit(lc, lc->clean_bits, i);
706 	}
707 
708 	r = rw_header(lc, WRITE);
709 	if (r)
710 		fail_log_device(lc);
711 	else {
712 		if (lc->touched_dirtied) {
713 			r = flush_header(lc);
714 			if (r) {
715 				lc->log_dev_flush_failed = 1;
716 				fail_log_device(lc);
717 			} else
718 				lc->touched_dirtied = 0;
719 		}
720 		lc->touched_cleaned = 0;
721 	}
722 
723 	return r;
724 }
725 
726 static void core_mark_region(struct dm_dirty_log *log, region_t region)
727 {
728 	struct log_c *lc = (struct log_c *) log->context;
729 	log_clear_bit(lc, lc->clean_bits, region);
730 }
731 
732 static void core_clear_region(struct dm_dirty_log *log, region_t region)
733 {
734 	struct log_c *lc = (struct log_c *) log->context;
735 	if (likely(!lc->flush_failed))
736 		log_set_bit(lc, lc->clean_bits, region);
737 }
738 
739 static int core_get_resync_work(struct dm_dirty_log *log, region_t *region)
740 {
741 	struct log_c *lc = (struct log_c *) log->context;
742 
743 	if (lc->sync_search >= lc->region_count)
744 		return 0;
745 
746 	do {
747 		*region = find_next_zero_bit_le(lc->sync_bits,
748 					     lc->region_count,
749 					     lc->sync_search);
750 		lc->sync_search = *region + 1;
751 
752 		if (*region >= lc->region_count)
753 			return 0;
754 
755 	} while (log_test_bit(lc->recovering_bits, *region));
756 
757 	log_set_bit(lc, lc->recovering_bits, *region);
758 	return 1;
759 }
760 
761 static void core_set_region_sync(struct dm_dirty_log *log, region_t region,
762 				 int in_sync)
763 {
764 	struct log_c *lc = (struct log_c *) log->context;
765 
766 	log_clear_bit(lc, lc->recovering_bits, region);
767 	if (in_sync) {
768 		log_set_bit(lc, lc->sync_bits, region);
769                 lc->sync_count++;
770         } else if (log_test_bit(lc->sync_bits, region)) {
771 		lc->sync_count--;
772 		log_clear_bit(lc, lc->sync_bits, region);
773 	}
774 }
775 
776 static region_t core_get_sync_count(struct dm_dirty_log *log)
777 {
778         struct log_c *lc = (struct log_c *) log->context;
779 
780         return lc->sync_count;
781 }
782 
783 #define	DMEMIT_SYNC \
784 	if (lc->sync != DEFAULTSYNC) \
785 		DMEMIT("%ssync ", lc->sync == NOSYNC ? "no" : "")
786 
787 static int core_status(struct dm_dirty_log *log, status_type_t status,
788 		       char *result, unsigned int maxlen)
789 {
790 	int sz = 0;
791 	struct log_c *lc = log->context;
792 
793 	switch(status) {
794 	case STATUSTYPE_INFO:
795 		DMEMIT("1 %s", log->type->name);
796 		break;
797 
798 	case STATUSTYPE_TABLE:
799 		DMEMIT("%s %u %u ", log->type->name,
800 		       lc->sync == DEFAULTSYNC ? 1 : 2, lc->region_size);
801 		DMEMIT_SYNC;
802 	}
803 
804 	return sz;
805 }
806 
807 static int disk_status(struct dm_dirty_log *log, status_type_t status,
808 		       char *result, unsigned int maxlen)
809 {
810 	int sz = 0;
811 	struct log_c *lc = log->context;
812 
813 	switch(status) {
814 	case STATUSTYPE_INFO:
815 		DMEMIT("3 %s %s %c", log->type->name, lc->log_dev->name,
816 		       lc->log_dev_flush_failed ? 'F' :
817 		       lc->log_dev_failed ? 'D' :
818 		       'A');
819 		break;
820 
821 	case STATUSTYPE_TABLE:
822 		DMEMIT("%s %u %s %u ", log->type->name,
823 		       lc->sync == DEFAULTSYNC ? 2 : 3, lc->log_dev->name,
824 		       lc->region_size);
825 		DMEMIT_SYNC;
826 	}
827 
828 	return sz;
829 }
830 
831 static struct dm_dirty_log_type _core_type = {
832 	.name = "core",
833 	.module = THIS_MODULE,
834 	.ctr = core_ctr,
835 	.dtr = core_dtr,
836 	.resume = core_resume,
837 	.get_region_size = core_get_region_size,
838 	.is_clean = core_is_clean,
839 	.in_sync = core_in_sync,
840 	.flush = core_flush,
841 	.mark_region = core_mark_region,
842 	.clear_region = core_clear_region,
843 	.get_resync_work = core_get_resync_work,
844 	.set_region_sync = core_set_region_sync,
845 	.get_sync_count = core_get_sync_count,
846 	.status = core_status,
847 };
848 
849 static struct dm_dirty_log_type _disk_type = {
850 	.name = "disk",
851 	.module = THIS_MODULE,
852 	.ctr = disk_ctr,
853 	.dtr = disk_dtr,
854 	.postsuspend = disk_flush,
855 	.resume = disk_resume,
856 	.get_region_size = core_get_region_size,
857 	.is_clean = core_is_clean,
858 	.in_sync = core_in_sync,
859 	.flush = disk_flush,
860 	.mark_region = core_mark_region,
861 	.clear_region = core_clear_region,
862 	.get_resync_work = core_get_resync_work,
863 	.set_region_sync = core_set_region_sync,
864 	.get_sync_count = core_get_sync_count,
865 	.status = disk_status,
866 };
867 
868 static int __init dm_dirty_log_init(void)
869 {
870 	int r;
871 
872 	r = dm_dirty_log_type_register(&_core_type);
873 	if (r)
874 		DMWARN("couldn't register core log");
875 
876 	r = dm_dirty_log_type_register(&_disk_type);
877 	if (r) {
878 		DMWARN("couldn't register disk type");
879 		dm_dirty_log_type_unregister(&_core_type);
880 	}
881 
882 	return r;
883 }
884 
885 static void __exit dm_dirty_log_exit(void)
886 {
887 	dm_dirty_log_type_unregister(&_disk_type);
888 	dm_dirty_log_type_unregister(&_core_type);
889 }
890 
891 module_init(dm_dirty_log_init);
892 module_exit(dm_dirty_log_exit);
893 
894 MODULE_DESCRIPTION(DM_NAME " dirty region log");
895 MODULE_AUTHOR("Joe Thornber, Heinz Mauelshagen <dm-devel@redhat.com>");
896 MODULE_LICENSE("GPL");
897