xref: /linux/drivers/md/dm-log.c (revision 2f804aca48322f02a8f44cca540663845ee80fb1) 
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2003 Sistina Software
4  * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
5  *
6  * This file is released under the LGPL.
7  */
8 
9 #include <linux/init.h>
10 #include <linux/slab.h>
11 #include <linux/module.h>
12 #include <linux/vmalloc.h>
13 #include <linux/dm-io.h>
14 #include <linux/dm-dirty-log.h>
15 
16 #include <linux/device-mapper.h>
17 
18 #define DM_MSG_PREFIX "dirty region log"
19 
20 static LIST_HEAD(_log_types);
21 static DEFINE_SPINLOCK(_lock);
22 
23 static struct dm_dirty_log_type *__find_dirty_log_type(const char *name)
24 {
25 	struct dm_dirty_log_type *log_type;
26 
27 	list_for_each_entry(log_type, &_log_types, list)
28 		if (!strcmp(name, log_type->name))
29 			return log_type;
30 
31 	return NULL;
32 }
33 
34 static struct dm_dirty_log_type *_get_dirty_log_type(const char *name)
35 {
36 	struct dm_dirty_log_type *log_type;
37 
38 	spin_lock(&_lock);
39 
40 	log_type = __find_dirty_log_type(name);
41 	if (log_type && !try_module_get(log_type->module))
42 		log_type = NULL;
43 
44 	spin_unlock(&_lock);
45 
46 	return log_type;
47 }
48 
49 /*
50  * get_type
51  * @type_name
52  *
53  * Attempt to retrieve the dm_dirty_log_type by name.  If not already
54  * available, attempt to load the appropriate module.
55  *
56  * Log modules are named "dm-log-" followed by the 'type_name'.
57  * Modules may contain multiple types.
58  * This function will first try the module "dm-log-<type_name>",
59  * then truncate 'type_name' on the last '-' and try again.
60  *
61  * For example, if type_name was "clustered-disk", it would search
62  * 'dm-log-clustered-disk' then 'dm-log-clustered'.
63  *
64  * Returns: dirty_log_type* on success, NULL on failure
65  */
66 static struct dm_dirty_log_type *get_type(const char *type_name)
67 {
68 	char *p, *type_name_dup;
69 	struct dm_dirty_log_type *log_type;
70 
71 	if (!type_name)
72 		return NULL;
73 
74 	log_type = _get_dirty_log_type(type_name);
75 	if (log_type)
76 		return log_type;
77 
78 	type_name_dup = kstrdup(type_name, GFP_KERNEL);
79 	if (!type_name_dup) {
80 		DMWARN("No memory left to attempt log module load for \"%s\"",
81 		       type_name);
82 		return NULL;
83 	}
84 
85 	while (request_module("dm-log-%s", type_name_dup) ||
86 	       !(log_type = _get_dirty_log_type(type_name))) {
87 		p = strrchr(type_name_dup, '-');
88 		if (!p)
89 			break;
90 		p[0] = '\0';
91 	}
92 
93 	if (!log_type)
94 		DMWARN("Module for logging type \"%s\" not found.", type_name);
95 
96 	kfree(type_name_dup);
97 
98 	return log_type;
99 }
100 
101 static void put_type(struct dm_dirty_log_type *type)
102 {
103 	if (!type)
104 		return;
105 
106 	spin_lock(&_lock);
107 	if (!__find_dirty_log_type(type->name))
108 		goto out;
109 
110 	module_put(type->module);
111 
112 out:
113 	spin_unlock(&_lock);
114 }
115 
116 int dm_dirty_log_type_register(struct dm_dirty_log_type *type)
117 {
118 	int r = 0;
119 
120 	spin_lock(&_lock);
121 	if (!__find_dirty_log_type(type->name))
122 		list_add(&type->list, &_log_types);
123 	else
124 		r = -EEXIST;
125 	spin_unlock(&_lock);
126 
127 	return r;
128 }
129 EXPORT_SYMBOL(dm_dirty_log_type_register);
130 
131 int dm_dirty_log_type_unregister(struct dm_dirty_log_type *type)
132 {
133 	spin_lock(&_lock);
134 
135 	if (!__find_dirty_log_type(type->name)) {
136 		spin_unlock(&_lock);
137 		return -EINVAL;
138 	}
139 
140 	list_del(&type->list);
141 
142 	spin_unlock(&_lock);
143 
144 	return 0;
145 }
146 EXPORT_SYMBOL(dm_dirty_log_type_unregister);
147 
148 struct dm_dirty_log *dm_dirty_log_create(const char *type_name,
149 			struct dm_target *ti,
150 			int (*flush_callback_fn)(struct dm_target *ti),
151 			unsigned int argc, char **argv)
152 {
153 	struct dm_dirty_log_type *type;
154 	struct dm_dirty_log *log;
155 
156 	log = kmalloc(sizeof(*log), GFP_KERNEL);
157 	if (!log)
158 		return NULL;
159 
160 	type = get_type(type_name);
161 	if (!type) {
162 		kfree(log);
163 		return NULL;
164 	}
165 
166 	log->flush_callback_fn = flush_callback_fn;
167 	log->type = type;
168 	if (type->ctr(log, ti, argc, argv)) {
169 		kfree(log);
170 		put_type(type);
171 		return NULL;
172 	}
173 
174 	return log;
175 }
176 EXPORT_SYMBOL(dm_dirty_log_create);
177 
178 void dm_dirty_log_destroy(struct dm_dirty_log *log)
179 {
180 	log->type->dtr(log);
181 	put_type(log->type);
182 	kfree(log);
183 }
184 EXPORT_SYMBOL(dm_dirty_log_destroy);
185 
186 /*
187  *---------------------------------------------------------------
188  * Persistent and core logs share a lot of their implementation.
189  * FIXME: need a reload method to be called from a resume
190  *---------------------------------------------------------------
191  */
192 /*
193  * Magic for persistent mirrors: "MiRr"
194  */
195 #define MIRROR_MAGIC 0x4D695272
196 
197 /*
198  * The on-disk version of the metadata.
199  */
200 #define MIRROR_DISK_VERSION 2
201 #define LOG_OFFSET 2
202 
203 struct log_header_disk {
204 	__le32 magic;
205 
206 	/*
207 	 * Simple, incrementing version. no backward
208 	 * compatibility.
209 	 */
210 	__le32 version;
211 	__le64 nr_regions;
212 } __packed;
213 
214 struct log_header_core {
215 	uint32_t magic;
216 	uint32_t version;
217 	uint64_t nr_regions;
218 };
219 
220 struct log_c {
221 	struct dm_target *ti;
222 	int touched_dirtied;
223 	int touched_cleaned;
224 	int flush_failed;
225 	uint32_t region_size;
226 	unsigned int region_count;
227 	region_t sync_count;
228 
229 	unsigned int bitset_uint32_count;
230 	uint32_t *clean_bits;
231 	uint32_t *sync_bits;
232 	uint32_t *recovering_bits;	/* FIXME: this seems excessive */
233 
234 	int sync_search;
235 
236 	/* Resync flag */
237 	enum sync {
238 		DEFAULTSYNC,	/* Synchronize if necessary */
239 		NOSYNC,		/* Devices known to be already in sync */
240 		FORCESYNC,	/* Force a sync to happen */
241 	} sync;
242 
243 	struct dm_io_request io_req;
244 
245 	/*
246 	 * Disk log fields
247 	 */
248 	int log_dev_failed;
249 	int log_dev_flush_failed;
250 	struct dm_dev *log_dev;
251 	struct log_header_core header;
252 
253 	struct dm_io_region header_location;
254 	struct log_header_disk *disk_header;
255 };
256 
257 /*
258  * The touched member needs to be updated every time we access
259  * one of the bitsets.
260  */
261 static inline int log_test_bit(uint32_t *bs, unsigned int bit)
262 {
263 	return test_bit_le(bit, bs) ? 1 : 0;
264 }
265 
266 static inline void log_set_bit(struct log_c *l,
267 			       uint32_t *bs, unsigned int bit)
268 {
269 	__set_bit_le(bit, bs);
270 	l->touched_cleaned = 1;
271 }
272 
273 static inline void log_clear_bit(struct log_c *l,
274 				 uint32_t *bs, unsigned int bit)
275 {
276 	__clear_bit_le(bit, bs);
277 	l->touched_dirtied = 1;
278 }
279 
280 /*
281  *---------------------------------------------------------------
282  * Header IO
283  *--------------------------------------------------------------
284  */
285 static void header_to_disk(struct log_header_core *core, struct log_header_disk *disk)
286 {
287 	disk->magic = cpu_to_le32(core->magic);
288 	disk->version = cpu_to_le32(core->version);
289 	disk->nr_regions = cpu_to_le64(core->nr_regions);
290 }
291 
292 static void header_from_disk(struct log_header_core *core, struct log_header_disk *disk)
293 {
294 	core->magic = le32_to_cpu(disk->magic);
295 	core->version = le32_to_cpu(disk->version);
296 	core->nr_regions = le64_to_cpu(disk->nr_regions);
297 }
298 
299 static int rw_header(struct log_c *lc, enum req_op op)
300 {
301 	lc->io_req.bi_opf = op;
302 
303 	return dm_io(&lc->io_req, 1, &lc->header_location, NULL);
304 }
305 
306 static int flush_header(struct log_c *lc)
307 {
308 	struct dm_io_region null_location = {
309 		.bdev = lc->header_location.bdev,
310 		.sector = 0,
311 		.count = 0,
312 	};
313 
314 	lc->io_req.bi_opf = REQ_OP_WRITE | REQ_PREFLUSH;
315 
316 	return dm_io(&lc->io_req, 1, &null_location, NULL);
317 }
318 
319 static int read_header(struct log_c *log)
320 {
321 	int r;
322 
323 	r = rw_header(log, REQ_OP_READ);
324 	if (r)
325 		return r;
326 
327 	header_from_disk(&log->header, log->disk_header);
328 
329 	/* New log required? */
330 	if (log->sync != DEFAULTSYNC || log->header.magic != MIRROR_MAGIC) {
331 		log->header.magic = MIRROR_MAGIC;
332 		log->header.version = MIRROR_DISK_VERSION;
333 		log->header.nr_regions = 0;
334 	}
335 
336 #ifdef __LITTLE_ENDIAN
337 	if (log->header.version == 1)
338 		log->header.version = 2;
339 #endif
340 
341 	if (log->header.version != MIRROR_DISK_VERSION) {
342 		DMWARN("incompatible disk log version");
343 		return -EINVAL;
344 	}
345 
346 	return 0;
347 }
348 
349 static int _check_region_size(struct dm_target *ti, uint32_t region_size)
350 {
351 	if (region_size < 2 || region_size > ti->len)
352 		return 0;
353 
354 	if (!is_power_of_2(region_size))
355 		return 0;
356 
357 	return 1;
358 }
359 
360 /*
361  *--------------------------------------------------------------
362  * core log constructor/destructor
363  *
364  * argv contains region_size followed optionally by [no]sync
365  *--------------------------------------------------------------
366  */
367 #define BYTE_SHIFT 3
368 static int create_log_context(struct dm_dirty_log *log, struct dm_target *ti,
369 			      unsigned int argc, char **argv,
370 			      struct dm_dev *dev)
371 {
372 	enum sync sync = DEFAULTSYNC;
373 
374 	struct log_c *lc;
375 	uint32_t region_size;
376 	unsigned int region_count;
377 	size_t bitset_size, buf_size;
378 	int r;
379 	char dummy;
380 
381 	if (argc < 1 || argc > 2) {
382 		DMWARN("wrong number of arguments to dirty region log");
383 		return -EINVAL;
384 	}
385 
386 	if (argc > 1) {
387 		if (!strcmp(argv[1], "sync"))
388 			sync = FORCESYNC;
389 		else if (!strcmp(argv[1], "nosync"))
390 			sync = NOSYNC;
391 		else {
392 			DMWARN("unrecognised sync argument to dirty region log: %s", argv[1]);
393 			return -EINVAL;
394 		}
395 	}
396 
397 	if (sscanf(argv[0], "%u%c", &region_size, &dummy) != 1 ||
398 	    !_check_region_size(ti, region_size)) {
399 		DMWARN("invalid region size %s", argv[0]);
400 		return -EINVAL;
401 	}
402 
403 	region_count = dm_sector_div_up(ti->len, region_size);
404 
405 	lc = kmalloc(sizeof(*lc), GFP_KERNEL);
406 	if (!lc) {
407 		DMWARN("couldn't allocate core log");
408 		return -ENOMEM;
409 	}
410 
411 	lc->ti = ti;
412 	lc->touched_dirtied = 0;
413 	lc->touched_cleaned = 0;
414 	lc->flush_failed = 0;
415 	lc->region_size = region_size;
416 	lc->region_count = region_count;
417 	lc->sync = sync;
418 
419 	/*
420 	 * Work out how many "unsigned long"s we need to hold the bitset.
421 	 */
422 	bitset_size = dm_round_up(region_count, BITS_PER_LONG);
423 	bitset_size >>= BYTE_SHIFT;
424 
425 	lc->bitset_uint32_count = bitset_size / sizeof(*lc->clean_bits);
426 
427 	/*
428 	 * Disk log?
429 	 */
430 	if (!dev) {
431 		lc->clean_bits = vmalloc(bitset_size);
432 		if (!lc->clean_bits) {
433 			DMWARN("couldn't allocate clean bitset");
434 			kfree(lc);
435 			return -ENOMEM;
436 		}
437 		lc->disk_header = NULL;
438 	} else {
439 		lc->log_dev = dev;
440 		lc->log_dev_failed = 0;
441 		lc->log_dev_flush_failed = 0;
442 		lc->header_location.bdev = lc->log_dev->bdev;
443 		lc->header_location.sector = 0;
444 
445 		/*
446 		 * Buffer holds both header and bitset.
447 		 */
448 		buf_size =
449 		    dm_round_up((LOG_OFFSET << SECTOR_SHIFT) + bitset_size,
450 				bdev_logical_block_size(lc->header_location.bdev));
451 
452 		if (buf_size > bdev_nr_bytes(dev->bdev)) {
453 			DMWARN("log device %s too small: need %llu bytes",
454 				dev->name, (unsigned long long)buf_size);
455 			kfree(lc);
456 			return -EINVAL;
457 		}
458 
459 		lc->header_location.count = buf_size >> SECTOR_SHIFT;
460 
461 		lc->io_req.mem.type = DM_IO_VMA;
462 		lc->io_req.notify.fn = NULL;
463 		lc->io_req.client = dm_io_client_create();
464 		if (IS_ERR(lc->io_req.client)) {
465 			r = PTR_ERR(lc->io_req.client);
466 			DMWARN("couldn't allocate disk io client");
467 			kfree(lc);
468 			return r;
469 		}
470 
471 		lc->disk_header = vmalloc(buf_size);
472 		if (!lc->disk_header) {
473 			DMWARN("couldn't allocate disk log buffer");
474 			dm_io_client_destroy(lc->io_req.client);
475 			kfree(lc);
476 			return -ENOMEM;
477 		}
478 
479 		lc->io_req.mem.ptr.vma = lc->disk_header;
480 		lc->clean_bits = (void *)lc->disk_header +
481 				 (LOG_OFFSET << SECTOR_SHIFT);
482 	}
483 
484 	memset(lc->clean_bits, -1, bitset_size);
485 
486 	lc->sync_bits = vmalloc(bitset_size);
487 	if (!lc->sync_bits) {
488 		DMWARN("couldn't allocate sync bitset");
489 		if (!dev)
490 			vfree(lc->clean_bits);
491 		else
492 			dm_io_client_destroy(lc->io_req.client);
493 		vfree(lc->disk_header);
494 		kfree(lc);
495 		return -ENOMEM;
496 	}
497 	memset(lc->sync_bits, (sync == NOSYNC) ? -1 : 0, bitset_size);
498 	lc->sync_count = (sync == NOSYNC) ? region_count : 0;
499 
500 	lc->recovering_bits = vzalloc(bitset_size);
501 	if (!lc->recovering_bits) {
502 		DMWARN("couldn't allocate sync bitset");
503 		vfree(lc->sync_bits);
504 		if (!dev)
505 			vfree(lc->clean_bits);
506 		else
507 			dm_io_client_destroy(lc->io_req.client);
508 		vfree(lc->disk_header);
509 		kfree(lc);
510 		return -ENOMEM;
511 	}
512 	lc->sync_search = 0;
513 	log->context = lc;
514 
515 	return 0;
516 }
517 
518 static int core_ctr(struct dm_dirty_log *log, struct dm_target *ti,
519 		    unsigned int argc, char **argv)
520 {
521 	return create_log_context(log, ti, argc, argv, NULL);
522 }
523 
524 static void destroy_log_context(struct log_c *lc)
525 {
526 	vfree(lc->sync_bits);
527 	vfree(lc->recovering_bits);
528 	kfree(lc);
529 }
530 
531 static void core_dtr(struct dm_dirty_log *log)
532 {
533 	struct log_c *lc = log->context;
534 
535 	vfree(lc->clean_bits);
536 	destroy_log_context(lc);
537 }
538 
539 /*
540  *---------------------------------------------------------------------
541  * disk log constructor/destructor
542  *
543  * argv contains log_device region_size followed optionally by [no]sync
544  *---------------------------------------------------------------------
545  */
546 static int disk_ctr(struct dm_dirty_log *log, struct dm_target *ti,
547 		    unsigned int argc, char **argv)
548 {
549 	int r;
550 	struct dm_dev *dev;
551 
552 	if (argc < 2 || argc > 3) {
553 		DMWARN("wrong number of arguments to disk dirty region log");
554 		return -EINVAL;
555 	}
556 
557 	r = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &dev);
558 	if (r)
559 		return r;
560 
561 	r = create_log_context(log, ti, argc - 1, argv + 1, dev);
562 	if (r) {
563 		dm_put_device(ti, dev);
564 		return r;
565 	}
566 
567 	return 0;
568 }
569 
570 static void disk_dtr(struct dm_dirty_log *log)
571 {
572 	struct log_c *lc = log->context;
573 
574 	dm_put_device(lc->ti, lc->log_dev);
575 	vfree(lc->disk_header);
576 	dm_io_client_destroy(lc->io_req.client);
577 	destroy_log_context(lc);
578 }
579 
580 static void fail_log_device(struct log_c *lc)
581 {
582 	if (lc->log_dev_failed)
583 		return;
584 
585 	lc->log_dev_failed = 1;
586 	dm_table_event(lc->ti->table);
587 }
588 
589 static int disk_resume(struct dm_dirty_log *log)
590 {
591 	int r;
592 	unsigned int i;
593 	struct log_c *lc = log->context;
594 	size_t size = lc->bitset_uint32_count * sizeof(uint32_t);
595 
596 	/* read the disk header */
597 	r = read_header(lc);
598 	if (r) {
599 		DMWARN("%s: Failed to read header on dirty region log device",
600 		       lc->log_dev->name);
601 		fail_log_device(lc);
602 		/*
603 		 * If the log device cannot be read, we must assume
604 		 * all regions are out-of-sync.  If we simply return
605 		 * here, the state will be uninitialized and could
606 		 * lead us to return 'in-sync' status for regions
607 		 * that are actually 'out-of-sync'.
608 		 */
609 		lc->header.nr_regions = 0;
610 	}
611 
612 	/* set or clear any new bits -- device has grown */
613 	if (lc->sync == NOSYNC)
614 		for (i = lc->header.nr_regions; i < lc->region_count; i++)
615 			/* FIXME: amazingly inefficient */
616 			log_set_bit(lc, lc->clean_bits, i);
617 	else
618 		for (i = lc->header.nr_regions; i < lc->region_count; i++)
619 			/* FIXME: amazingly inefficient */
620 			log_clear_bit(lc, lc->clean_bits, i);
621 
622 	/* clear any old bits -- device has shrunk */
623 	for (i = lc->region_count; i % BITS_PER_LONG; i++)
624 		log_clear_bit(lc, lc->clean_bits, i);
625 
626 	/* copy clean across to sync */
627 	memcpy(lc->sync_bits, lc->clean_bits, size);
628 	lc->sync_count = memweight(lc->clean_bits,
629 				lc->bitset_uint32_count * sizeof(uint32_t));
630 	lc->sync_search = 0;
631 
632 	/* set the correct number of regions in the header */
633 	lc->header.nr_regions = lc->region_count;
634 
635 	header_to_disk(&lc->header, lc->disk_header);
636 
637 	/* write the new header */
638 	r = rw_header(lc, REQ_OP_WRITE);
639 	if (!r) {
640 		r = flush_header(lc);
641 		if (r)
642 			lc->log_dev_flush_failed = 1;
643 	}
644 	if (r) {
645 		DMWARN("%s: Failed to write header on dirty region log device",
646 		       lc->log_dev->name);
647 		fail_log_device(lc);
648 	}
649 
650 	return r;
651 }
652 
653 static uint32_t core_get_region_size(struct dm_dirty_log *log)
654 {
655 	struct log_c *lc = log->context;
656 
657 	return lc->region_size;
658 }
659 
660 static int core_resume(struct dm_dirty_log *log)
661 {
662 	struct log_c *lc = log->context;
663 
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 = log->context;
671 
672 	return log_test_bit(lc->clean_bits, region);
673 }
674 
675 static int core_in_sync(struct dm_dirty_log *log, region_t region, int block)
676 {
677 	struct log_c *lc = log->context;
678 
679 	return log_test_bit(lc->sync_bits, region);
680 }
681 
682 static int core_flush(struct dm_dirty_log *log)
683 {
684 	/* no op */
685 	return 0;
686 }
687 
688 static int disk_flush(struct dm_dirty_log *log)
689 {
690 	int r, i;
691 	struct log_c *lc = log->context;
692 
693 	/* only write if the log has changed */
694 	if (!lc->touched_cleaned && !lc->touched_dirtied)
695 		return 0;
696 
697 	if (lc->touched_cleaned && log->flush_callback_fn &&
698 	    log->flush_callback_fn(lc->ti)) {
699 		/*
700 		 * At this point it is impossible to determine which
701 		 * regions are clean and which are dirty (without
702 		 * re-reading the log off disk). So mark all of them
703 		 * dirty.
704 		 */
705 		lc->flush_failed = 1;
706 		for (i = 0; i < lc->region_count; i++)
707 			log_clear_bit(lc, lc->clean_bits, i);
708 	}
709 
710 	r = rw_header(lc, REQ_OP_WRITE);
711 	if (r)
712 		fail_log_device(lc);
713 	else {
714 		if (lc->touched_dirtied) {
715 			r = flush_header(lc);
716 			if (r) {
717 				lc->log_dev_flush_failed = 1;
718 				fail_log_device(lc);
719 			} else
720 				lc->touched_dirtied = 0;
721 		}
722 		lc->touched_cleaned = 0;
723 	}
724 
725 	return r;
726 }
727 
728 static void core_mark_region(struct dm_dirty_log *log, region_t region)
729 {
730 	struct log_c *lc = log->context;
731 
732 	log_clear_bit(lc, lc->clean_bits, region);
733 }
734 
735 static void core_clear_region(struct dm_dirty_log *log, region_t region)
736 {
737 	struct log_c *lc = log->context;
738 
739 	if (likely(!lc->flush_failed))
740 		log_set_bit(lc, lc->clean_bits, region);
741 }
742 
743 static int core_get_resync_work(struct dm_dirty_log *log, region_t *region)
744 {
745 	struct log_c *lc = log->context;
746 
747 	if (lc->sync_search >= lc->region_count)
748 		return 0;
749 
750 	do {
751 		*region = find_next_zero_bit_le(lc->sync_bits,
752 					     lc->region_count,
753 					     lc->sync_search);
754 		lc->sync_search = *region + 1;
755 
756 		if (*region >= lc->region_count)
757 			return 0;
758 
759 	} while (log_test_bit(lc->recovering_bits, *region));
760 
761 	log_set_bit(lc, lc->recovering_bits, *region);
762 	return 1;
763 }
764 
765 static void core_set_region_sync(struct dm_dirty_log *log, region_t region,
766 				 int in_sync)
767 {
768 	struct log_c *lc = log->context;
769 
770 	log_clear_bit(lc, lc->recovering_bits, region);
771 	if (in_sync) {
772 		log_set_bit(lc, lc->sync_bits, region);
773 		lc->sync_count++;
774 	} else if (log_test_bit(lc->sync_bits, region)) {
775 		lc->sync_count--;
776 		log_clear_bit(lc, lc->sync_bits, region);
777 	}
778 }
779 
780 static region_t core_get_sync_count(struct dm_dirty_log *log)
781 {
782 	struct log_c *lc = log->context;
783 
784 	return lc->sync_count;
785 }
786 
787 #define	DMEMIT_SYNC \
788 	do { \
789 		if (lc->sync != DEFAULTSYNC) \
790 			DMEMIT("%ssync ", lc->sync == NOSYNC ? "no" : ""); \
791 	} while (0)
792 
793 static int core_status(struct dm_dirty_log *log, status_type_t status,
794 		       char *result, unsigned int maxlen)
795 {
796 	int sz = 0;
797 	struct log_c *lc = log->context;
798 
799 	switch (status) {
800 	case STATUSTYPE_INFO:
801 		DMEMIT("1 %s", log->type->name);
802 		break;
803 
804 	case STATUSTYPE_TABLE:
805 		DMEMIT("%s %u %u ", log->type->name,
806 		       lc->sync == DEFAULTSYNC ? 1 : 2, lc->region_size);
807 		DMEMIT_SYNC;
808 		break;
809 
810 	case STATUSTYPE_IMA:
811 		*result = '\0';
812 		break;
813 	}
814 
815 	return sz;
816 }
817 
818 static int disk_status(struct dm_dirty_log *log, status_type_t status,
819 		       char *result, unsigned int maxlen)
820 {
821 	int sz = 0;
822 	struct log_c *lc = log->context;
823 
824 	switch (status) {
825 	case STATUSTYPE_INFO:
826 		DMEMIT("3 %s %s %c", log->type->name, lc->log_dev->name,
827 		       lc->log_dev_flush_failed ? 'F' :
828 		       lc->log_dev_failed ? 'D' :
829 		       'A');
830 		break;
831 
832 	case STATUSTYPE_TABLE:
833 		DMEMIT("%s %u %s %u ", log->type->name,
834 		       lc->sync == DEFAULTSYNC ? 2 : 3, lc->log_dev->name,
835 		       lc->region_size);
836 		DMEMIT_SYNC;
837 		break;
838 
839 	case STATUSTYPE_IMA:
840 		*result = '\0';
841 		break;
842 	}
843 
844 	return sz;
845 }
846 
847 static struct dm_dirty_log_type _core_type = {
848 	.name = "core",
849 	.module = THIS_MODULE,
850 	.ctr = core_ctr,
851 	.dtr = core_dtr,
852 	.resume = core_resume,
853 	.get_region_size = core_get_region_size,
854 	.is_clean = core_is_clean,
855 	.in_sync = core_in_sync,
856 	.flush = core_flush,
857 	.mark_region = core_mark_region,
858 	.clear_region = core_clear_region,
859 	.get_resync_work = core_get_resync_work,
860 	.set_region_sync = core_set_region_sync,
861 	.get_sync_count = core_get_sync_count,
862 	.status = core_status,
863 };
864 
865 static struct dm_dirty_log_type _disk_type = {
866 	.name = "disk",
867 	.module = THIS_MODULE,
868 	.ctr = disk_ctr,
869 	.dtr = disk_dtr,
870 	.postsuspend = disk_flush,
871 	.resume = disk_resume,
872 	.get_region_size = core_get_region_size,
873 	.is_clean = core_is_clean,
874 	.in_sync = core_in_sync,
875 	.flush = disk_flush,
876 	.mark_region = core_mark_region,
877 	.clear_region = core_clear_region,
878 	.get_resync_work = core_get_resync_work,
879 	.set_region_sync = core_set_region_sync,
880 	.get_sync_count = core_get_sync_count,
881 	.status = disk_status,
882 };
883 
884 static int __init dm_dirty_log_init(void)
885 {
886 	int r;
887 
888 	r = dm_dirty_log_type_register(&_core_type);
889 	if (r)
890 		DMWARN("couldn't register core log");
891 
892 	r = dm_dirty_log_type_register(&_disk_type);
893 	if (r) {
894 		DMWARN("couldn't register disk type");
895 		dm_dirty_log_type_unregister(&_core_type);
896 	}
897 
898 	return r;
899 }
900 
901 static void __exit dm_dirty_log_exit(void)
902 {
903 	dm_dirty_log_type_unregister(&_disk_type);
904 	dm_dirty_log_type_unregister(&_core_type);
905 }
906 
907 module_init(dm_dirty_log_init);
908 module_exit(dm_dirty_log_exit);
909 
910 MODULE_DESCRIPTION(DM_NAME " dirty region log");
911 MODULE_AUTHOR("Joe Thornber, Heinz Mauelshagen <dm-devel@redhat.com>");
912 MODULE_LICENSE("GPL");
913