Merge git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-module-and-param
[linux-2.6] / drivers / md / dm-log.c
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                                          unsigned int argc, char **argv)
150 {
151         struct dm_dirty_log_type *type;
152         struct dm_dirty_log *log;
153
154         log = kmalloc(sizeof(*log), GFP_KERNEL);
155         if (!log)
156                 return NULL;
157
158         type = get_type(type_name);
159         if (!type) {
160                 kfree(log);
161                 return NULL;
162         }
163
164         log->type = type;
165         if (type->ctr(log, ti, argc, argv)) {
166                 kfree(log);
167                 put_type(type);
168                 return NULL;
169         }
170
171         return log;
172 }
173 EXPORT_SYMBOL(dm_dirty_log_create);
174
175 void dm_dirty_log_destroy(struct dm_dirty_log *log)
176 {
177         log->type->dtr(log);
178         put_type(log->type);
179         kfree(log);
180 }
181 EXPORT_SYMBOL(dm_dirty_log_destroy);
182
183 /*-----------------------------------------------------------------
184  * Persistent and core logs share a lot of their implementation.
185  * FIXME: need a reload method to be called from a resume
186  *---------------------------------------------------------------*/
187 /*
188  * Magic for persistent mirrors: "MiRr"
189  */
190 #define MIRROR_MAGIC 0x4D695272
191
192 /*
193  * The on-disk version of the metadata.
194  */
195 #define MIRROR_DISK_VERSION 2
196 #define LOG_OFFSET 2
197
198 struct log_header {
199         uint32_t magic;
200
201         /*
202          * Simple, incrementing version. no backward
203          * compatibility.
204          */
205         uint32_t version;
206         sector_t nr_regions;
207 };
208
209 struct log_c {
210         struct dm_target *ti;
211         int touched;
212         uint32_t region_size;
213         unsigned int region_count;
214         region_t sync_count;
215
216         unsigned bitset_uint32_count;
217         uint32_t *clean_bits;
218         uint32_t *sync_bits;
219         uint32_t *recovering_bits;      /* FIXME: this seems excessive */
220
221         int sync_search;
222
223         /* Resync flag */
224         enum sync {
225                 DEFAULTSYNC,    /* Synchronize if necessary */
226                 NOSYNC,         /* Devices known to be already in sync */
227                 FORCESYNC,      /* Force a sync to happen */
228         } sync;
229
230         struct dm_io_request io_req;
231
232         /*
233          * Disk log fields
234          */
235         int log_dev_failed;
236         struct dm_dev *log_dev;
237         struct log_header header;
238
239         struct dm_io_region header_location;
240         struct log_header *disk_header;
241 };
242
243 /*
244  * The touched member needs to be updated every time we access
245  * one of the bitsets.
246  */
247 static inline int log_test_bit(uint32_t *bs, unsigned bit)
248 {
249         return ext2_test_bit(bit, (unsigned long *) bs) ? 1 : 0;
250 }
251
252 static inline void log_set_bit(struct log_c *l,
253                                uint32_t *bs, unsigned bit)
254 {
255         ext2_set_bit(bit, (unsigned long *) bs);
256         l->touched = 1;
257 }
258
259 static inline void log_clear_bit(struct log_c *l,
260                                  uint32_t *bs, unsigned bit)
261 {
262         ext2_clear_bit(bit, (unsigned long *) bs);
263         l->touched = 1;
264 }
265
266 /*----------------------------------------------------------------
267  * Header IO
268  *--------------------------------------------------------------*/
269 static void header_to_disk(struct log_header *core, struct log_header *disk)
270 {
271         disk->magic = cpu_to_le32(core->magic);
272         disk->version = cpu_to_le32(core->version);
273         disk->nr_regions = cpu_to_le64(core->nr_regions);
274 }
275
276 static void header_from_disk(struct log_header *core, struct log_header *disk)
277 {
278         core->magic = le32_to_cpu(disk->magic);
279         core->version = le32_to_cpu(disk->version);
280         core->nr_regions = le64_to_cpu(disk->nr_regions);
281 }
282
283 static int rw_header(struct log_c *lc, int rw)
284 {
285         lc->io_req.bi_rw = rw;
286
287         return dm_io(&lc->io_req, 1, &lc->header_location, NULL);
288 }
289
290 static int read_header(struct log_c *log)
291 {
292         int r;
293
294         r = rw_header(log, READ);
295         if (r)
296                 return r;
297
298         header_from_disk(&log->header, log->disk_header);
299
300         /* New log required? */
301         if (log->sync != DEFAULTSYNC || log->header.magic != MIRROR_MAGIC) {
302                 log->header.magic = MIRROR_MAGIC;
303                 log->header.version = MIRROR_DISK_VERSION;
304                 log->header.nr_regions = 0;
305         }
306
307 #ifdef __LITTLE_ENDIAN
308         if (log->header.version == 1)
309                 log->header.version = 2;
310 #endif
311
312         if (log->header.version != MIRROR_DISK_VERSION) {
313                 DMWARN("incompatible disk log version");
314                 return -EINVAL;
315         }
316
317         return 0;
318 }
319
320 static int _check_region_size(struct dm_target *ti, uint32_t region_size)
321 {
322         if (region_size < 2 || region_size > ti->len)
323                 return 0;
324
325         if (!is_power_of_2(region_size))
326                 return 0;
327
328         return 1;
329 }
330
331 /*----------------------------------------------------------------
332  * core log constructor/destructor
333  *
334  * argv contains region_size followed optionally by [no]sync
335  *--------------------------------------------------------------*/
336 #define BYTE_SHIFT 3
337 static int create_log_context(struct dm_dirty_log *log, struct dm_target *ti,
338                               unsigned int argc, char **argv,
339                               struct dm_dev *dev)
340 {
341         enum sync sync = DEFAULTSYNC;
342
343         struct log_c *lc;
344         uint32_t region_size;
345         unsigned int region_count;
346         size_t bitset_size, buf_size;
347         int r;
348
349         if (argc < 1 || argc > 2) {
350                 DMWARN("wrong number of arguments to dirty region log");
351                 return -EINVAL;
352         }
353
354         if (argc > 1) {
355                 if (!strcmp(argv[1], "sync"))
356                         sync = FORCESYNC;
357                 else if (!strcmp(argv[1], "nosync"))
358                         sync = NOSYNC;
359                 else {
360                         DMWARN("unrecognised sync argument to "
361                                "dirty region log: %s", argv[1]);
362                         return -EINVAL;
363                 }
364         }
365
366         if (sscanf(argv[0], "%u", &region_size) != 1 ||
367             !_check_region_size(ti, region_size)) {
368                 DMWARN("invalid region size %s", argv[0]);
369                 return -EINVAL;
370         }
371
372         region_count = dm_sector_div_up(ti->len, region_size);
373
374         lc = kmalloc(sizeof(*lc), GFP_KERNEL);
375         if (!lc) {
376                 DMWARN("couldn't allocate core log");
377                 return -ENOMEM;
378         }
379
380         lc->ti = ti;
381         lc->touched = 0;
382         lc->region_size = region_size;
383         lc->region_count = region_count;
384         lc->sync = sync;
385
386         /*
387          * Work out how many "unsigned long"s we need to hold the bitset.
388          */
389         bitset_size = dm_round_up(region_count,
390                                   sizeof(*lc->clean_bits) << BYTE_SHIFT);
391         bitset_size >>= BYTE_SHIFT;
392
393         lc->bitset_uint32_count = bitset_size / sizeof(*lc->clean_bits);
394
395         /*
396          * Disk log?
397          */
398         if (!dev) {
399                 lc->clean_bits = vmalloc(bitset_size);
400                 if (!lc->clean_bits) {
401                         DMWARN("couldn't allocate clean bitset");
402                         kfree(lc);
403                         return -ENOMEM;
404                 }
405                 lc->disk_header = NULL;
406         } else {
407                 lc->log_dev = dev;
408                 lc->log_dev_failed = 0;
409                 lc->header_location.bdev = lc->log_dev->bdev;
410                 lc->header_location.sector = 0;
411
412                 /*
413                  * Buffer holds both header and bitset.
414                  */
415                 buf_size = dm_round_up((LOG_OFFSET << SECTOR_SHIFT) +
416                                        bitset_size, ti->limits.hardsect_size);
417
418                 if (buf_size > dev->bdev->bd_inode->i_size) {
419                         DMWARN("log device %s too small: need %llu bytes",
420                                 dev->name, (unsigned long long)buf_size);
421                         kfree(lc);
422                         return -EINVAL;
423                 }
424
425                 lc->header_location.count = buf_size >> SECTOR_SHIFT;
426
427                 lc->io_req.mem.type = DM_IO_VMA;
428                 lc->io_req.notify.fn = NULL;
429                 lc->io_req.client = dm_io_client_create(dm_div_up(buf_size,
430                                                                    PAGE_SIZE));
431                 if (IS_ERR(lc->io_req.client)) {
432                         r = PTR_ERR(lc->io_req.client);
433                         DMWARN("couldn't allocate disk io client");
434                         kfree(lc);
435                         return -ENOMEM;
436                 }
437
438                 lc->disk_header = vmalloc(buf_size);
439                 if (!lc->disk_header) {
440                         DMWARN("couldn't allocate disk log buffer");
441                         dm_io_client_destroy(lc->io_req.client);
442                         kfree(lc);
443                         return -ENOMEM;
444                 }
445
446                 lc->io_req.mem.ptr.vma = lc->disk_header;
447                 lc->clean_bits = (void *)lc->disk_header +
448                                  (LOG_OFFSET << SECTOR_SHIFT);
449         }
450
451         memset(lc->clean_bits, -1, bitset_size);
452
453         lc->sync_bits = vmalloc(bitset_size);
454         if (!lc->sync_bits) {
455                 DMWARN("couldn't allocate sync bitset");
456                 if (!dev)
457                         vfree(lc->clean_bits);
458                 else
459                         dm_io_client_destroy(lc->io_req.client);
460                 vfree(lc->disk_header);
461                 kfree(lc);
462                 return -ENOMEM;
463         }
464         memset(lc->sync_bits, (sync == NOSYNC) ? -1 : 0, bitset_size);
465         lc->sync_count = (sync == NOSYNC) ? region_count : 0;
466
467         lc->recovering_bits = vmalloc(bitset_size);
468         if (!lc->recovering_bits) {
469                 DMWARN("couldn't allocate sync bitset");
470                 vfree(lc->sync_bits);
471                 if (!dev)
472                         vfree(lc->clean_bits);
473                 else
474                         dm_io_client_destroy(lc->io_req.client);
475                 vfree(lc->disk_header);
476                 kfree(lc);
477                 return -ENOMEM;
478         }
479         memset(lc->recovering_bits, 0, bitset_size);
480         lc->sync_search = 0;
481         log->context = lc;
482
483         return 0;
484 }
485
486 static int core_ctr(struct dm_dirty_log *log, struct dm_target *ti,
487                     unsigned int argc, char **argv)
488 {
489         return create_log_context(log, ti, argc, argv, NULL);
490 }
491
492 static void destroy_log_context(struct log_c *lc)
493 {
494         vfree(lc->sync_bits);
495         vfree(lc->recovering_bits);
496         kfree(lc);
497 }
498
499 static void core_dtr(struct dm_dirty_log *log)
500 {
501         struct log_c *lc = (struct log_c *) log->context;
502
503         vfree(lc->clean_bits);
504         destroy_log_context(lc);
505 }
506
507 /*----------------------------------------------------------------
508  * disk log constructor/destructor
509  *
510  * argv contains log_device region_size followed optionally by [no]sync
511  *--------------------------------------------------------------*/
512 static int disk_ctr(struct dm_dirty_log *log, struct dm_target *ti,
513                     unsigned int argc, char **argv)
514 {
515         int r;
516         struct dm_dev *dev;
517
518         if (argc < 2 || argc > 3) {
519                 DMWARN("wrong number of arguments to disk dirty region log");
520                 return -EINVAL;
521         }
522
523         r = dm_get_device(ti, argv[0], 0, 0 /* FIXME */,
524                           FMODE_READ | FMODE_WRITE, &dev);
525         if (r)
526                 return r;
527
528         r = create_log_context(log, ti, argc - 1, argv + 1, dev);
529         if (r) {
530                 dm_put_device(ti, dev);
531                 return r;
532         }
533
534         return 0;
535 }
536
537 static void disk_dtr(struct dm_dirty_log *log)
538 {
539         struct log_c *lc = (struct log_c *) log->context;
540
541         dm_put_device(lc->ti, lc->log_dev);
542         vfree(lc->disk_header);
543         dm_io_client_destroy(lc->io_req.client);
544         destroy_log_context(lc);
545 }
546
547 static int count_bits32(uint32_t *addr, unsigned size)
548 {
549         int count = 0, i;
550
551         for (i = 0; i < size; i++) {
552                 count += hweight32(*(addr+i));
553         }
554         return count;
555 }
556
557 static void fail_log_device(struct log_c *lc)
558 {
559         if (lc->log_dev_failed)
560                 return;
561
562         lc->log_dev_failed = 1;
563         dm_table_event(lc->ti->table);
564 }
565
566 static int disk_resume(struct dm_dirty_log *log)
567 {
568         int r;
569         unsigned i;
570         struct log_c *lc = (struct log_c *) log->context;
571         size_t size = lc->bitset_uint32_count * sizeof(uint32_t);
572
573         /* read the disk header */
574         r = read_header(lc);
575         if (r) {
576                 DMWARN("%s: Failed to read header on dirty region log device",
577                        lc->log_dev->name);
578                 fail_log_device(lc);
579                 /*
580                  * If the log device cannot be read, we must assume
581                  * all regions are out-of-sync.  If we simply return
582                  * here, the state will be uninitialized and could
583                  * lead us to return 'in-sync' status for regions
584                  * that are actually 'out-of-sync'.
585                  */
586                 lc->header.nr_regions = 0;
587         }
588
589         /* set or clear any new bits -- device has grown */
590         if (lc->sync == NOSYNC)
591                 for (i = lc->header.nr_regions; i < lc->region_count; i++)
592                         /* FIXME: amazingly inefficient */
593                         log_set_bit(lc, lc->clean_bits, i);
594         else
595                 for (i = lc->header.nr_regions; i < lc->region_count; i++)
596                         /* FIXME: amazingly inefficient */
597                         log_clear_bit(lc, lc->clean_bits, i);
598
599         /* clear any old bits -- device has shrunk */
600         for (i = lc->region_count; i % (sizeof(*lc->clean_bits) << BYTE_SHIFT); i++)
601                 log_clear_bit(lc, lc->clean_bits, i);
602
603         /* copy clean across to sync */
604         memcpy(lc->sync_bits, lc->clean_bits, size);
605         lc->sync_count = count_bits32(lc->clean_bits, lc->bitset_uint32_count);
606         lc->sync_search = 0;
607
608         /* set the correct number of regions in the header */
609         lc->header.nr_regions = lc->region_count;
610
611         header_to_disk(&lc->header, lc->disk_header);
612
613         /* write the new header */
614         r = rw_header(lc, WRITE);
615         if (r) {
616                 DMWARN("%s: Failed to write header on dirty region log device",
617                        lc->log_dev->name);
618                 fail_log_device(lc);
619         }
620
621         return r;
622 }
623
624 static uint32_t core_get_region_size(struct dm_dirty_log *log)
625 {
626         struct log_c *lc = (struct log_c *) log->context;
627         return lc->region_size;
628 }
629
630 static int core_resume(struct dm_dirty_log *log)
631 {
632         struct log_c *lc = (struct log_c *) log->context;
633         lc->sync_search = 0;
634         return 0;
635 }
636
637 static int core_is_clean(struct dm_dirty_log *log, region_t region)
638 {
639         struct log_c *lc = (struct log_c *) log->context;
640         return log_test_bit(lc->clean_bits, region);
641 }
642
643 static int core_in_sync(struct dm_dirty_log *log, region_t region, int block)
644 {
645         struct log_c *lc = (struct log_c *) log->context;
646         return log_test_bit(lc->sync_bits, region);
647 }
648
649 static int core_flush(struct dm_dirty_log *log)
650 {
651         /* no op */
652         return 0;
653 }
654
655 static int disk_flush(struct dm_dirty_log *log)
656 {
657         int r;
658         struct log_c *lc = (struct log_c *) log->context;
659
660         /* only write if the log has changed */
661         if (!lc->touched)
662                 return 0;
663
664         r = rw_header(lc, WRITE);
665         if (r)
666                 fail_log_device(lc);
667         else
668                 lc->touched = 0;
669
670         return r;
671 }
672
673 static void core_mark_region(struct dm_dirty_log *log, region_t region)
674 {
675         struct log_c *lc = (struct log_c *) log->context;
676         log_clear_bit(lc, lc->clean_bits, region);
677 }
678
679 static void core_clear_region(struct dm_dirty_log *log, region_t region)
680 {
681         struct log_c *lc = (struct log_c *) log->context;
682         log_set_bit(lc, lc->clean_bits, region);
683 }
684
685 static int core_get_resync_work(struct dm_dirty_log *log, region_t *region)
686 {
687         struct log_c *lc = (struct log_c *) log->context;
688
689         if (lc->sync_search >= lc->region_count)
690                 return 0;
691
692         do {
693                 *region = ext2_find_next_zero_bit(
694                                              (unsigned long *) lc->sync_bits,
695                                              lc->region_count,
696                                              lc->sync_search);
697                 lc->sync_search = *region + 1;
698
699                 if (*region >= lc->region_count)
700                         return 0;
701
702         } while (log_test_bit(lc->recovering_bits, *region));
703
704         log_set_bit(lc, lc->recovering_bits, *region);
705         return 1;
706 }
707
708 static void core_set_region_sync(struct dm_dirty_log *log, region_t region,
709                                  int in_sync)
710 {
711         struct log_c *lc = (struct log_c *) log->context;
712
713         log_clear_bit(lc, lc->recovering_bits, region);
714         if (in_sync) {
715                 log_set_bit(lc, lc->sync_bits, region);
716                 lc->sync_count++;
717         } else if (log_test_bit(lc->sync_bits, region)) {
718                 lc->sync_count--;
719                 log_clear_bit(lc, lc->sync_bits, region);
720         }
721 }
722
723 static region_t core_get_sync_count(struct dm_dirty_log *log)
724 {
725         struct log_c *lc = (struct log_c *) log->context;
726
727         return lc->sync_count;
728 }
729
730 #define DMEMIT_SYNC \
731         if (lc->sync != DEFAULTSYNC) \
732                 DMEMIT("%ssync ", lc->sync == NOSYNC ? "no" : "")
733
734 static int core_status(struct dm_dirty_log *log, status_type_t status,
735                        char *result, unsigned int maxlen)
736 {
737         int sz = 0;
738         struct log_c *lc = log->context;
739
740         switch(status) {
741         case STATUSTYPE_INFO:
742                 DMEMIT("1 %s", log->type->name);
743                 break;
744
745         case STATUSTYPE_TABLE:
746                 DMEMIT("%s %u %u ", log->type->name,
747                        lc->sync == DEFAULTSYNC ? 1 : 2, lc->region_size);
748                 DMEMIT_SYNC;
749         }
750
751         return sz;
752 }
753
754 static int disk_status(struct dm_dirty_log *log, status_type_t status,
755                        char *result, unsigned int maxlen)
756 {
757         int sz = 0;
758         struct log_c *lc = log->context;
759
760         switch(status) {
761         case STATUSTYPE_INFO:
762                 DMEMIT("3 %s %s %c", log->type->name, lc->log_dev->name,
763                        lc->log_dev_failed ? 'D' : 'A');
764                 break;
765
766         case STATUSTYPE_TABLE:
767                 DMEMIT("%s %u %s %u ", log->type->name,
768                        lc->sync == DEFAULTSYNC ? 2 : 3, lc->log_dev->name,
769                        lc->region_size);
770                 DMEMIT_SYNC;
771         }
772
773         return sz;
774 }
775
776 static struct dm_dirty_log_type _core_type = {
777         .name = "core",
778         .module = THIS_MODULE,
779         .ctr = core_ctr,
780         .dtr = core_dtr,
781         .resume = core_resume,
782         .get_region_size = core_get_region_size,
783         .is_clean = core_is_clean,
784         .in_sync = core_in_sync,
785         .flush = core_flush,
786         .mark_region = core_mark_region,
787         .clear_region = core_clear_region,
788         .get_resync_work = core_get_resync_work,
789         .set_region_sync = core_set_region_sync,
790         .get_sync_count = core_get_sync_count,
791         .status = core_status,
792 };
793
794 static struct dm_dirty_log_type _disk_type = {
795         .name = "disk",
796         .module = THIS_MODULE,
797         .ctr = disk_ctr,
798         .dtr = disk_dtr,
799         .postsuspend = disk_flush,
800         .resume = disk_resume,
801         .get_region_size = core_get_region_size,
802         .is_clean = core_is_clean,
803         .in_sync = core_in_sync,
804         .flush = disk_flush,
805         .mark_region = core_mark_region,
806         .clear_region = core_clear_region,
807         .get_resync_work = core_get_resync_work,
808         .set_region_sync = core_set_region_sync,
809         .get_sync_count = core_get_sync_count,
810         .status = disk_status,
811 };
812
813 static int __init dm_dirty_log_init(void)
814 {
815         int r;
816
817         r = dm_dirty_log_type_register(&_core_type);
818         if (r)
819                 DMWARN("couldn't register core log");
820
821         r = dm_dirty_log_type_register(&_disk_type);
822         if (r) {
823                 DMWARN("couldn't register disk type");
824                 dm_dirty_log_type_unregister(&_core_type);
825         }
826
827         return r;
828 }
829
830 static void __exit dm_dirty_log_exit(void)
831 {
832         dm_dirty_log_type_unregister(&_disk_type);
833         dm_dirty_log_type_unregister(&_core_type);
834 }
835
836 module_init(dm_dirty_log_init);
837 module_exit(dm_dirty_log_exit);
838
839 MODULE_DESCRIPTION(DM_NAME " dirty region log");
840 MODULE_AUTHOR("Joe Thornber, Heinz Mauelshagen <dm-devel@redhat.com>");
841 MODULE_LICENSE("GPL");