xref: /linux/drivers/md/dm-log.c (revision 12871a0bd67dd4db4418e1daafcd46e9d329ef10)
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 {
201 	uint32_t magic;
202 
203 	/*
204 	 * Simple, incrementing version. no backward
205 	 * compatibility.
206 	 */
207 	uint32_t version;
208 	sector_t nr_regions;
209 };
210 
211 struct log_c {
212 	struct dm_target *ti;
213 	int touched_dirtied;
214 	int touched_cleaned;
215 	int flush_failed;
216 	uint32_t region_size;
217 	unsigned int region_count;
218 	region_t sync_count;
219 
220 	unsigned bitset_uint32_count;
221 	uint32_t *clean_bits;
222 	uint32_t *sync_bits;
223 	uint32_t *recovering_bits;	/* FIXME: this seems excessive */
224 
225 	int sync_search;
226 
227 	/* Resync flag */
228 	enum sync {
229 		DEFAULTSYNC,	/* Synchronize if necessary */
230 		NOSYNC,		/* Devices known to be already in sync */
231 		FORCESYNC,	/* Force a sync to happen */
232 	} sync;
233 
234 	struct dm_io_request io_req;
235 
236 	/*
237 	 * Disk log fields
238 	 */
239 	int log_dev_failed;
240 	int log_dev_flush_failed;
241 	struct dm_dev *log_dev;
242 	struct log_header header;
243 
244 	struct dm_io_region header_location;
245 	struct log_header *disk_header;
246 };
247 
248 /*
249  * The touched member needs to be updated every time we access
250  * one of the bitsets.
251  */
252 static inline int log_test_bit(uint32_t *bs, unsigned bit)
253 {
254 	return test_bit_le(bit, (unsigned long *) bs) ? 1 : 0;
255 }
256 
257 static inline void log_set_bit(struct log_c *l,
258 			       uint32_t *bs, unsigned bit)
259 {
260 	__test_and_set_bit_le(bit, (unsigned long *) bs);
261 	l->touched_cleaned = 1;
262 }
263 
264 static inline void log_clear_bit(struct log_c *l,
265 				 uint32_t *bs, unsigned bit)
266 {
267 	__test_and_clear_bit_le(bit, (unsigned long *) bs);
268 	l->touched_dirtied = 1;
269 }
270 
271 /*----------------------------------------------------------------
272  * Header IO
273  *--------------------------------------------------------------*/
274 static void header_to_disk(struct log_header *core, struct log_header *disk)
275 {
276 	disk->magic = cpu_to_le32(core->magic);
277 	disk->version = cpu_to_le32(core->version);
278 	disk->nr_regions = cpu_to_le64(core->nr_regions);
279 }
280 
281 static void header_from_disk(struct log_header *core, struct log_header *disk)
282 {
283 	core->magic = le32_to_cpu(disk->magic);
284 	core->version = le32_to_cpu(disk->version);
285 	core->nr_regions = le64_to_cpu(disk->nr_regions);
286 }
287 
288 static int rw_header(struct log_c *lc, int rw)
289 {
290 	lc->io_req.bi_rw = rw;
291 
292 	return dm_io(&lc->io_req, 1, &lc->header_location, NULL);
293 }
294 
295 static int flush_header(struct log_c *lc)
296 {
297 	struct dm_io_region null_location = {
298 		.bdev = lc->header_location.bdev,
299 		.sector = 0,
300 		.count = 0,
301 	};
302 
303 	lc->io_req.bi_rw = WRITE_FLUSH;
304 
305 	return dm_io(&lc->io_req, 1, &null_location, NULL);
306 }
307 
308 static int read_header(struct log_c *log)
309 {
310 	int r;
311 
312 	r = rw_header(log, READ);
313 	if (r)
314 		return r;
315 
316 	header_from_disk(&log->header, log->disk_header);
317 
318 	/* New log required? */
319 	if (log->sync != DEFAULTSYNC || log->header.magic != MIRROR_MAGIC) {
320 		log->header.magic = MIRROR_MAGIC;
321 		log->header.version = MIRROR_DISK_VERSION;
322 		log->header.nr_regions = 0;
323 	}
324 
325 #ifdef __LITTLE_ENDIAN
326 	if (log->header.version == 1)
327 		log->header.version = 2;
328 #endif
329 
330 	if (log->header.version != MIRROR_DISK_VERSION) {
331 		DMWARN("incompatible disk log version");
332 		return -EINVAL;
333 	}
334 
335 	return 0;
336 }
337 
338 static int _check_region_size(struct dm_target *ti, uint32_t region_size)
339 {
340 	if (region_size < 2 || region_size > ti->len)
341 		return 0;
342 
343 	if (!is_power_of_2(region_size))
344 		return 0;
345 
346 	return 1;
347 }
348 
349 /*----------------------------------------------------------------
350  * core log constructor/destructor
351  *
352  * argv contains region_size followed optionally by [no]sync
353  *--------------------------------------------------------------*/
354 #define BYTE_SHIFT 3
355 static int create_log_context(struct dm_dirty_log *log, struct dm_target *ti,
356 			      unsigned int argc, char **argv,
357 			      struct dm_dev *dev)
358 {
359 	enum sync sync = DEFAULTSYNC;
360 
361 	struct log_c *lc;
362 	uint32_t region_size;
363 	unsigned int region_count;
364 	size_t bitset_size, buf_size;
365 	int r;
366 
367 	if (argc < 1 || argc > 2) {
368 		DMWARN("wrong number of arguments to dirty region log");
369 		return -EINVAL;
370 	}
371 
372 	if (argc > 1) {
373 		if (!strcmp(argv[1], "sync"))
374 			sync = FORCESYNC;
375 		else if (!strcmp(argv[1], "nosync"))
376 			sync = NOSYNC;
377 		else {
378 			DMWARN("unrecognised sync argument to "
379 			       "dirty region log: %s", argv[1]);
380 			return -EINVAL;
381 		}
382 	}
383 
384 	if (sscanf(argv[0], "%u", &region_size) != 1 ||
385 	    !_check_region_size(ti, region_size)) {
386 		DMWARN("invalid region size %s", argv[0]);
387 		return -EINVAL;
388 	}
389 
390 	region_count = dm_sector_div_up(ti->len, region_size);
391 
392 	lc = kmalloc(sizeof(*lc), GFP_KERNEL);
393 	if (!lc) {
394 		DMWARN("couldn't allocate core log");
395 		return -ENOMEM;
396 	}
397 
398 	lc->ti = ti;
399 	lc->touched_dirtied = 0;
400 	lc->touched_cleaned = 0;
401 	lc->flush_failed = 0;
402 	lc->region_size = region_size;
403 	lc->region_count = region_count;
404 	lc->sync = sync;
405 
406 	/*
407 	 * Work out how many "unsigned long"s we need to hold the bitset.
408 	 */
409 	bitset_size = dm_round_up(region_count,
410 				  sizeof(*lc->clean_bits) << BYTE_SHIFT);
411 	bitset_size >>= BYTE_SHIFT;
412 
413 	lc->bitset_uint32_count = bitset_size / sizeof(*lc->clean_bits);
414 
415 	/*
416 	 * Disk log?
417 	 */
418 	if (!dev) {
419 		lc->clean_bits = vmalloc(bitset_size);
420 		if (!lc->clean_bits) {
421 			DMWARN("couldn't allocate clean bitset");
422 			kfree(lc);
423 			return -ENOMEM;
424 		}
425 		lc->disk_header = NULL;
426 	} else {
427 		lc->log_dev = dev;
428 		lc->log_dev_failed = 0;
429 		lc->log_dev_flush_failed = 0;
430 		lc->header_location.bdev = lc->log_dev->bdev;
431 		lc->header_location.sector = 0;
432 
433 		/*
434 		 * Buffer holds both header and bitset.
435 		 */
436 		buf_size =
437 		    dm_round_up((LOG_OFFSET << SECTOR_SHIFT) + bitset_size,
438 				bdev_logical_block_size(lc->header_location.
439 							    bdev));
440 
441 		if (buf_size > i_size_read(dev->bdev->bd_inode)) {
442 			DMWARN("log device %s too small: need %llu bytes",
443 				dev->name, (unsigned long long)buf_size);
444 			kfree(lc);
445 			return -EINVAL;
446 		}
447 
448 		lc->header_location.count = buf_size >> SECTOR_SHIFT;
449 
450 		lc->io_req.mem.type = DM_IO_VMA;
451 		lc->io_req.notify.fn = NULL;
452 		lc->io_req.client = dm_io_client_create();
453 		if (IS_ERR(lc->io_req.client)) {
454 			r = PTR_ERR(lc->io_req.client);
455 			DMWARN("couldn't allocate disk io client");
456 			kfree(lc);
457 			return r;
458 		}
459 
460 		lc->disk_header = vmalloc(buf_size);
461 		if (!lc->disk_header) {
462 			DMWARN("couldn't allocate disk log buffer");
463 			dm_io_client_destroy(lc->io_req.client);
464 			kfree(lc);
465 			return -ENOMEM;
466 		}
467 
468 		lc->io_req.mem.ptr.vma = lc->disk_header;
469 		lc->clean_bits = (void *)lc->disk_header +
470 				 (LOG_OFFSET << SECTOR_SHIFT);
471 	}
472 
473 	memset(lc->clean_bits, -1, bitset_size);
474 
475 	lc->sync_bits = vmalloc(bitset_size);
476 	if (!lc->sync_bits) {
477 		DMWARN("couldn't allocate sync bitset");
478 		if (!dev)
479 			vfree(lc->clean_bits);
480 		else
481 			dm_io_client_destroy(lc->io_req.client);
482 		vfree(lc->disk_header);
483 		kfree(lc);
484 		return -ENOMEM;
485 	}
486 	memset(lc->sync_bits, (sync == NOSYNC) ? -1 : 0, bitset_size);
487 	lc->sync_count = (sync == NOSYNC) ? region_count : 0;
488 
489 	lc->recovering_bits = vmalloc(bitset_size);
490 	if (!lc->recovering_bits) {
491 		DMWARN("couldn't allocate sync bitset");
492 		vfree(lc->sync_bits);
493 		if (!dev)
494 			vfree(lc->clean_bits);
495 		else
496 			dm_io_client_destroy(lc->io_req.client);
497 		vfree(lc->disk_header);
498 		kfree(lc);
499 		return -ENOMEM;
500 	}
501 	memset(lc->recovering_bits, 0, bitset_size);
502 	lc->sync_search = 0;
503 	log->context = lc;
504 
505 	return 0;
506 }
507 
508 static int core_ctr(struct dm_dirty_log *log, struct dm_target *ti,
509 		    unsigned int argc, char **argv)
510 {
511 	return create_log_context(log, ti, argc, argv, NULL);
512 }
513 
514 static void destroy_log_context(struct log_c *lc)
515 {
516 	vfree(lc->sync_bits);
517 	vfree(lc->recovering_bits);
518 	kfree(lc);
519 }
520 
521 static void core_dtr(struct dm_dirty_log *log)
522 {
523 	struct log_c *lc = (struct log_c *) log->context;
524 
525 	vfree(lc->clean_bits);
526 	destroy_log_context(lc);
527 }
528 
529 /*----------------------------------------------------------------
530  * disk log constructor/destructor
531  *
532  * argv contains log_device region_size followed optionally by [no]sync
533  *--------------------------------------------------------------*/
534 static int disk_ctr(struct dm_dirty_log *log, struct dm_target *ti,
535 		    unsigned int argc, char **argv)
536 {
537 	int r;
538 	struct dm_dev *dev;
539 
540 	if (argc < 2 || argc > 3) {
541 		DMWARN("wrong number of arguments to disk dirty region log");
542 		return -EINVAL;
543 	}
544 
545 	r = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &dev);
546 	if (r)
547 		return r;
548 
549 	r = create_log_context(log, ti, argc - 1, argv + 1, dev);
550 	if (r) {
551 		dm_put_device(ti, dev);
552 		return r;
553 	}
554 
555 	return 0;
556 }
557 
558 static void disk_dtr(struct dm_dirty_log *log)
559 {
560 	struct log_c *lc = (struct log_c *) log->context;
561 
562 	dm_put_device(lc->ti, lc->log_dev);
563 	vfree(lc->disk_header);
564 	dm_io_client_destroy(lc->io_req.client);
565 	destroy_log_context(lc);
566 }
567 
568 static int count_bits32(uint32_t *addr, unsigned size)
569 {
570 	int count = 0, i;
571 
572 	for (i = 0; i < size; i++) {
573 		count += hweight32(*(addr+i));
574 	}
575 	return count;
576 }
577 
578 static void fail_log_device(struct log_c *lc)
579 {
580 	if (lc->log_dev_failed)
581 		return;
582 
583 	lc->log_dev_failed = 1;
584 	dm_table_event(lc->ti->table);
585 }
586 
587 static int disk_resume(struct dm_dirty_log *log)
588 {
589 	int r;
590 	unsigned i;
591 	struct log_c *lc = (struct log_c *) log->context;
592 	size_t size = lc->bitset_uint32_count * sizeof(uint32_t);
593 
594 	/* read the disk header */
595 	r = read_header(lc);
596 	if (r) {
597 		DMWARN("%s: Failed to read header on dirty region log device",
598 		       lc->log_dev->name);
599 		fail_log_device(lc);
600 		/*
601 		 * If the log device cannot be read, we must assume
602 		 * all regions are out-of-sync.  If we simply return
603 		 * here, the state will be uninitialized and could
604 		 * lead us to return 'in-sync' status for regions
605 		 * that are actually 'out-of-sync'.
606 		 */
607 		lc->header.nr_regions = 0;
608 	}
609 
610 	/* set or clear any new bits -- device has grown */
611 	if (lc->sync == NOSYNC)
612 		for (i = lc->header.nr_regions; i < lc->region_count; i++)
613 			/* FIXME: amazingly inefficient */
614 			log_set_bit(lc, lc->clean_bits, i);
615 	else
616 		for (i = lc->header.nr_regions; i < lc->region_count; i++)
617 			/* FIXME: amazingly inefficient */
618 			log_clear_bit(lc, lc->clean_bits, i);
619 
620 	/* clear any old bits -- device has shrunk */
621 	for (i = lc->region_count; i % (sizeof(*lc->clean_bits) << BYTE_SHIFT); i++)
622 		log_clear_bit(lc, lc->clean_bits, i);
623 
624 	/* copy clean across to sync */
625 	memcpy(lc->sync_bits, lc->clean_bits, size);
626 	lc->sync_count = count_bits32(lc->clean_bits, lc->bitset_uint32_count);
627 	lc->sync_search = 0;
628 
629 	/* set the correct number of regions in the header */
630 	lc->header.nr_regions = lc->region_count;
631 
632 	header_to_disk(&lc->header, lc->disk_header);
633 
634 	/* write the new header */
635 	r = rw_header(lc, WRITE);
636 	if (!r) {
637 		r = flush_header(lc);
638 		if (r)
639 			lc->log_dev_flush_failed = 1;
640 	}
641 	if (r) {
642 		DMWARN("%s: Failed to write header on dirty region log device",
643 		       lc->log_dev->name);
644 		fail_log_device(lc);
645 	}
646 
647 	return r;
648 }
649 
650 static uint32_t core_get_region_size(struct dm_dirty_log *log)
651 {
652 	struct log_c *lc = (struct log_c *) log->context;
653 	return lc->region_size;
654 }
655 
656 static int core_resume(struct dm_dirty_log *log)
657 {
658 	struct log_c *lc = (struct log_c *) log->context;
659 	lc->sync_search = 0;
660 	return 0;
661 }
662 
663 static int core_is_clean(struct dm_dirty_log *log, region_t region)
664 {
665 	struct log_c *lc = (struct log_c *) log->context;
666 	return log_test_bit(lc->clean_bits, region);
667 }
668 
669 static int core_in_sync(struct dm_dirty_log *log, region_t region, int block)
670 {
671 	struct log_c *lc = (struct log_c *) log->context;
672 	return log_test_bit(lc->sync_bits, region);
673 }
674 
675 static int core_flush(struct dm_dirty_log *log)
676 {
677 	/* no op */
678 	return 0;
679 }
680 
681 static int disk_flush(struct dm_dirty_log *log)
682 {
683 	int r, i;
684 	struct log_c *lc = log->context;
685 
686 	/* only write if the log has changed */
687 	if (!lc->touched_cleaned && !lc->touched_dirtied)
688 		return 0;
689 
690 	if (lc->touched_cleaned && log->flush_callback_fn &&
691 	    log->flush_callback_fn(lc->ti)) {
692 		/*
693 		 * At this point it is impossible to determine which
694 		 * regions are clean and which are dirty (without
695 		 * re-reading the log off disk). So mark all of them
696 		 * dirty.
697 		 */
698 		lc->flush_failed = 1;
699 		for (i = 0; i < lc->region_count; i++)
700 			log_clear_bit(lc, lc->clean_bits, i);
701 	}
702 
703 	r = rw_header(lc, WRITE);
704 	if (r)
705 		fail_log_device(lc);
706 	else {
707 		if (lc->touched_dirtied) {
708 			r = flush_header(lc);
709 			if (r) {
710 				lc->log_dev_flush_failed = 1;
711 				fail_log_device(lc);
712 			} else
713 				lc->touched_dirtied = 0;
714 		}
715 		lc->touched_cleaned = 0;
716 	}
717 
718 	return r;
719 }
720 
721 static void core_mark_region(struct dm_dirty_log *log, region_t region)
722 {
723 	struct log_c *lc = (struct log_c *) log->context;
724 	log_clear_bit(lc, lc->clean_bits, region);
725 }
726 
727 static void core_clear_region(struct dm_dirty_log *log, region_t region)
728 {
729 	struct log_c *lc = (struct log_c *) log->context;
730 	if (likely(!lc->flush_failed))
731 		log_set_bit(lc, lc->clean_bits, region);
732 }
733 
734 static int core_get_resync_work(struct dm_dirty_log *log, region_t *region)
735 {
736 	struct log_c *lc = (struct log_c *) log->context;
737 
738 	if (lc->sync_search >= lc->region_count)
739 		return 0;
740 
741 	do {
742 		*region = find_next_zero_bit_le(
743 					     (unsigned long *) lc->sync_bits,
744 					     lc->region_count,
745 					     lc->sync_search);
746 		lc->sync_search = *region + 1;
747 
748 		if (*region >= lc->region_count)
749 			return 0;
750 
751 	} while (log_test_bit(lc->recovering_bits, *region));
752 
753 	log_set_bit(lc, lc->recovering_bits, *region);
754 	return 1;
755 }
756 
757 static void core_set_region_sync(struct dm_dirty_log *log, region_t region,
758 				 int in_sync)
759 {
760 	struct log_c *lc = (struct log_c *) log->context;
761 
762 	log_clear_bit(lc, lc->recovering_bits, region);
763 	if (in_sync) {
764 		log_set_bit(lc, lc->sync_bits, region);
765                 lc->sync_count++;
766         } else if (log_test_bit(lc->sync_bits, region)) {
767 		lc->sync_count--;
768 		log_clear_bit(lc, lc->sync_bits, region);
769 	}
770 }
771 
772 static region_t core_get_sync_count(struct dm_dirty_log *log)
773 {
774         struct log_c *lc = (struct log_c *) log->context;
775 
776         return lc->sync_count;
777 }
778 
779 #define	DMEMIT_SYNC \
780 	if (lc->sync != DEFAULTSYNC) \
781 		DMEMIT("%ssync ", lc->sync == NOSYNC ? "no" : "")
782 
783 static int core_status(struct dm_dirty_log *log, status_type_t status,
784 		       char *result, unsigned int maxlen)
785 {
786 	int sz = 0;
787 	struct log_c *lc = log->context;
788 
789 	switch(status) {
790 	case STATUSTYPE_INFO:
791 		DMEMIT("1 %s", log->type->name);
792 		break;
793 
794 	case STATUSTYPE_TABLE:
795 		DMEMIT("%s %u %u ", log->type->name,
796 		       lc->sync == DEFAULTSYNC ? 1 : 2, lc->region_size);
797 		DMEMIT_SYNC;
798 	}
799 
800 	return sz;
801 }
802 
803 static int disk_status(struct dm_dirty_log *log, status_type_t status,
804 		       char *result, unsigned int maxlen)
805 {
806 	int sz = 0;
807 	struct log_c *lc = log->context;
808 
809 	switch(status) {
810 	case STATUSTYPE_INFO:
811 		DMEMIT("3 %s %s %c", log->type->name, lc->log_dev->name,
812 		       lc->log_dev_flush_failed ? 'F' :
813 		       lc->log_dev_failed ? 'D' :
814 		       'A');
815 		break;
816 
817 	case STATUSTYPE_TABLE:
818 		DMEMIT("%s %u %s %u ", log->type->name,
819 		       lc->sync == DEFAULTSYNC ? 2 : 3, lc->log_dev->name,
820 		       lc->region_size);
821 		DMEMIT_SYNC;
822 	}
823 
824 	return sz;
825 }
826 
827 static struct dm_dirty_log_type _core_type = {
828 	.name = "core",
829 	.module = THIS_MODULE,
830 	.ctr = core_ctr,
831 	.dtr = core_dtr,
832 	.resume = core_resume,
833 	.get_region_size = core_get_region_size,
834 	.is_clean = core_is_clean,
835 	.in_sync = core_in_sync,
836 	.flush = core_flush,
837 	.mark_region = core_mark_region,
838 	.clear_region = core_clear_region,
839 	.get_resync_work = core_get_resync_work,
840 	.set_region_sync = core_set_region_sync,
841 	.get_sync_count = core_get_sync_count,
842 	.status = core_status,
843 };
844 
845 static struct dm_dirty_log_type _disk_type = {
846 	.name = "disk",
847 	.module = THIS_MODULE,
848 	.ctr = disk_ctr,
849 	.dtr = disk_dtr,
850 	.postsuspend = disk_flush,
851 	.resume = disk_resume,
852 	.get_region_size = core_get_region_size,
853 	.is_clean = core_is_clean,
854 	.in_sync = core_in_sync,
855 	.flush = disk_flush,
856 	.mark_region = core_mark_region,
857 	.clear_region = core_clear_region,
858 	.get_resync_work = core_get_resync_work,
859 	.set_region_sync = core_set_region_sync,
860 	.get_sync_count = core_get_sync_count,
861 	.status = disk_status,
862 };
863 
864 static int __init dm_dirty_log_init(void)
865 {
866 	int r;
867 
868 	r = dm_dirty_log_type_register(&_core_type);
869 	if (r)
870 		DMWARN("couldn't register core log");
871 
872 	r = dm_dirty_log_type_register(&_disk_type);
873 	if (r) {
874 		DMWARN("couldn't register disk type");
875 		dm_dirty_log_type_unregister(&_core_type);
876 	}
877 
878 	return r;
879 }
880 
881 static void __exit dm_dirty_log_exit(void)
882 {
883 	dm_dirty_log_type_unregister(&_disk_type);
884 	dm_dirty_log_type_unregister(&_core_type);
885 }
886 
887 module_init(dm_dirty_log_init);
888 module_exit(dm_dirty_log_exit);
889 
890 MODULE_DESCRIPTION(DM_NAME " dirty region log");
891 MODULE_AUTHOR("Joe Thornber, Heinz Mauelshagen <dm-devel@redhat.com>");
892 MODULE_LICENSE("GPL");
893