blob: 64b764bd02cc3e1ff15d9aa26df40f536d34f22b [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * Copyright (C) 2003 Sistina Software
3 *
4 * This file is released under the LGPL.
5 */
6
7#include <linux/init.h>
8#include <linux/slab.h>
9#include <linux/module.h>
10#include <linux/vmalloc.h>
11
12#include "dm-log.h"
13#include "dm-io.h"
14
Alasdair G Kergon72d94862006-06-26 00:27:35 -070015#define DM_MSG_PREFIX "mirror log"
16
Linus Torvalds1da177e2005-04-16 15:20:36 -070017static LIST_HEAD(_log_types);
18static DEFINE_SPINLOCK(_lock);
19
20int dm_register_dirty_log_type(struct dirty_log_type *type)
21{
22 spin_lock(&_lock);
23 type->use_count = 0;
24 list_add(&type->list, &_log_types);
25 spin_unlock(&_lock);
26
27 return 0;
28}
29
30int dm_unregister_dirty_log_type(struct dirty_log_type *type)
31{
32 spin_lock(&_lock);
33
34 if (type->use_count)
35 DMWARN("Attempt to unregister a log type that is still in use");
36 else
37 list_del(&type->list);
38
39 spin_unlock(&_lock);
40
41 return 0;
42}
43
44static struct dirty_log_type *get_type(const char *type_name)
45{
46 struct dirty_log_type *type;
47
48 spin_lock(&_lock);
49 list_for_each_entry (type, &_log_types, list)
50 if (!strcmp(type_name, type->name)) {
51 if (!type->use_count && !try_module_get(type->module)){
52 spin_unlock(&_lock);
53 return NULL;
54 }
55 type->use_count++;
56 spin_unlock(&_lock);
57 return type;
58 }
59
60 spin_unlock(&_lock);
61 return NULL;
62}
63
64static void put_type(struct dirty_log_type *type)
65{
66 spin_lock(&_lock);
67 if (!--type->use_count)
68 module_put(type->module);
69 spin_unlock(&_lock);
70}
71
72struct dirty_log *dm_create_dirty_log(const char *type_name, struct dm_target *ti,
73 unsigned int argc, char **argv)
74{
75 struct dirty_log_type *type;
76 struct dirty_log *log;
77
78 log = kmalloc(sizeof(*log), GFP_KERNEL);
79 if (!log)
80 return NULL;
81
82 type = get_type(type_name);
83 if (!type) {
84 kfree(log);
85 return NULL;
86 }
87
88 log->type = type;
89 if (type->ctr(log, ti, argc, argv)) {
90 kfree(log);
91 put_type(type);
92 return NULL;
93 }
94
95 return log;
96}
97
98void dm_destroy_dirty_log(struct dirty_log *log)
99{
100 log->type->dtr(log);
101 put_type(log->type);
102 kfree(log);
103}
104
105/*-----------------------------------------------------------------
106 * Persistent and core logs share a lot of their implementation.
107 * FIXME: need a reload method to be called from a resume
108 *---------------------------------------------------------------*/
109/*
110 * Magic for persistent mirrors: "MiRr"
111 */
112#define MIRROR_MAGIC 0x4D695272
113
114/*
115 * The on-disk version of the metadata.
116 */
Patrick Caulfielda4fc4712006-02-01 03:04:51 -0800117#define MIRROR_DISK_VERSION 2
Linus Torvalds1da177e2005-04-16 15:20:36 -0700118#define LOG_OFFSET 2
119
120struct log_header {
121 uint32_t magic;
122
123 /*
124 * Simple, incrementing version. no backward
125 * compatibility.
126 */
127 uint32_t version;
128 sector_t nr_regions;
129};
130
131struct log_c {
132 struct dm_target *ti;
133 int touched;
134 uint32_t region_size;
135 unsigned int region_count;
136 region_t sync_count;
137
138 unsigned bitset_uint32_count;
139 uint32_t *clean_bits;
140 uint32_t *sync_bits;
141 uint32_t *recovering_bits; /* FIXME: this seems excessive */
142
143 int sync_search;
144
145 /* Resync flag */
146 enum sync {
147 DEFAULTSYNC, /* Synchronize if necessary */
148 NOSYNC, /* Devices known to be already in sync */
149 FORCESYNC, /* Force a sync to happen */
150 } sync;
151
152 /*
153 * Disk log fields
154 */
155 struct dm_dev *log_dev;
156 struct log_header header;
157
158 struct io_region header_location;
159 struct log_header *disk_header;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700160};
161
162/*
163 * The touched member needs to be updated every time we access
164 * one of the bitsets.
165 */
166static inline int log_test_bit(uint32_t *bs, unsigned bit)
167{
Patrick Caulfielda4fc4712006-02-01 03:04:51 -0800168 return ext2_test_bit(bit, (unsigned long *) bs) ? 1 : 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700169}
170
171static inline void log_set_bit(struct log_c *l,
172 uint32_t *bs, unsigned bit)
173{
Patrick Caulfielda4fc4712006-02-01 03:04:51 -0800174 ext2_set_bit(bit, (unsigned long *) bs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700175 l->touched = 1;
176}
177
178static inline void log_clear_bit(struct log_c *l,
179 uint32_t *bs, unsigned bit)
180{
Patrick Caulfielda4fc4712006-02-01 03:04:51 -0800181 ext2_clear_bit(bit, (unsigned long *) bs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182 l->touched = 1;
183}
184
185/*----------------------------------------------------------------
186 * Header IO
187 *--------------------------------------------------------------*/
188static void header_to_disk(struct log_header *core, struct log_header *disk)
189{
190 disk->magic = cpu_to_le32(core->magic);
191 disk->version = cpu_to_le32(core->version);
192 disk->nr_regions = cpu_to_le64(core->nr_regions);
193}
194
195static void header_from_disk(struct log_header *core, struct log_header *disk)
196{
197 core->magic = le32_to_cpu(disk->magic);
198 core->version = le32_to_cpu(disk->version);
199 core->nr_regions = le64_to_cpu(disk->nr_regions);
200}
201
202static int read_header(struct log_c *log)
203{
204 int r;
205 unsigned long ebits;
206
207 r = dm_io_sync_vm(1, &log->header_location, READ,
208 log->disk_header, &ebits);
209 if (r)
210 return r;
211
212 header_from_disk(&log->header, log->disk_header);
213
214 /* New log required? */
215 if (log->sync != DEFAULTSYNC || log->header.magic != MIRROR_MAGIC) {
216 log->header.magic = MIRROR_MAGIC;
217 log->header.version = MIRROR_DISK_VERSION;
218 log->header.nr_regions = 0;
219 }
220
Patrick Caulfielda4fc4712006-02-01 03:04:51 -0800221#ifdef __LITTLE_ENDIAN
222 if (log->header.version == 1)
223 log->header.version = 2;
224#endif
225
Linus Torvalds1da177e2005-04-16 15:20:36 -0700226 if (log->header.version != MIRROR_DISK_VERSION) {
227 DMWARN("incompatible disk log version");
228 return -EINVAL;
229 }
230
231 return 0;
232}
233
234static inline int write_header(struct log_c *log)
235{
236 unsigned long ebits;
237
238 header_to_disk(&log->header, log->disk_header);
239 return dm_io_sync_vm(1, &log->header_location, WRITE,
240 log->disk_header, &ebits);
241}
242
243/*----------------------------------------------------------------
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244 * core log constructor/destructor
245 *
246 * argv contains region_size followed optionally by [no]sync
247 *--------------------------------------------------------------*/
248#define BYTE_SHIFT 3
Alasdair G Kergonb7cca192006-06-26 00:27:29 -0700249static int create_log_context(struct dirty_log *log, struct dm_target *ti,
250 unsigned int argc, char **argv,
251 struct dm_dev *dev)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700252{
253 enum sync sync = DEFAULTSYNC;
254
255 struct log_c *lc;
256 uint32_t region_size;
257 unsigned int region_count;
Alasdair G Kergonb7cca192006-06-26 00:27:29 -0700258 size_t bitset_size, buf_size;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700259
260 if (argc < 1 || argc > 2) {
261 DMWARN("wrong number of arguments to mirror log");
262 return -EINVAL;
263 }
264
265 if (argc > 1) {
266 if (!strcmp(argv[1], "sync"))
267 sync = FORCESYNC;
268 else if (!strcmp(argv[1], "nosync"))
269 sync = NOSYNC;
270 else {
271 DMWARN("unrecognised sync argument to mirror log: %s",
272 argv[1]);
273 return -EINVAL;
274 }
275 }
276
277 if (sscanf(argv[0], "%u", &region_size) != 1) {
278 DMWARN("invalid region size string");
279 return -EINVAL;
280 }
281
282 region_count = dm_sector_div_up(ti->len, region_size);
283
284 lc = kmalloc(sizeof(*lc), GFP_KERNEL);
285 if (!lc) {
286 DMWARN("couldn't allocate core log");
287 return -ENOMEM;
288 }
289
290 lc->ti = ti;
291 lc->touched = 0;
292 lc->region_size = region_size;
293 lc->region_count = region_count;
294 lc->sync = sync;
295
296 /*
Alasdair G Kergon0e568222005-11-21 21:32:34 -0800297 * Work out how many "unsigned long"s we need to hold the bitset.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700298 */
299 bitset_size = dm_round_up(region_count,
Alasdair G Kergon29121bd2006-06-26 00:27:29 -0700300 sizeof(*lc->clean_bits) << BYTE_SHIFT);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700301 bitset_size >>= BYTE_SHIFT;
302
Alasdair G Kergon29121bd2006-06-26 00:27:29 -0700303 lc->bitset_uint32_count = bitset_size / sizeof(*lc->clean_bits);
Alasdair G Kergonb7cca192006-06-26 00:27:29 -0700304
305 /*
306 * Disk log?
307 */
308 if (!dev) {
309 lc->clean_bits = vmalloc(bitset_size);
310 if (!lc->clean_bits) {
311 DMWARN("couldn't allocate clean bitset");
312 kfree(lc);
313 return -ENOMEM;
314 }
315 lc->disk_header = NULL;
316 } else {
317 lc->log_dev = dev;
318 lc->header_location.bdev = lc->log_dev->bdev;
319 lc->header_location.sector = 0;
320
321 /*
322 * Buffer holds both header and bitset.
323 */
324 buf_size = dm_round_up((LOG_OFFSET << SECTOR_SHIFT) +
325 bitset_size, ti->limits.hardsect_size);
326 lc->header_location.count = buf_size >> SECTOR_SHIFT;
327
328 lc->disk_header = vmalloc(buf_size);
329 if (!lc->disk_header) {
330 DMWARN("couldn't allocate disk log buffer");
331 kfree(lc);
332 return -ENOMEM;
333 }
334
335 lc->clean_bits = (void *)lc->disk_header +
336 (LOG_OFFSET << SECTOR_SHIFT);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700337 }
Alasdair G Kergonb7cca192006-06-26 00:27:29 -0700338
Linus Torvalds1da177e2005-04-16 15:20:36 -0700339 memset(lc->clean_bits, -1, bitset_size);
340
341 lc->sync_bits = vmalloc(bitset_size);
342 if (!lc->sync_bits) {
343 DMWARN("couldn't allocate sync bitset");
Alasdair G Kergonb7cca192006-06-26 00:27:29 -0700344 if (!dev)
345 vfree(lc->clean_bits);
346 vfree(lc->disk_header);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700347 kfree(lc);
348 return -ENOMEM;
349 }
350 memset(lc->sync_bits, (sync == NOSYNC) ? -1 : 0, bitset_size);
351 lc->sync_count = (sync == NOSYNC) ? region_count : 0;
352
353 lc->recovering_bits = vmalloc(bitset_size);
354 if (!lc->recovering_bits) {
355 DMWARN("couldn't allocate sync bitset");
356 vfree(lc->sync_bits);
Alasdair G Kergonb7cca192006-06-26 00:27:29 -0700357 if (!dev)
358 vfree(lc->clean_bits);
359 vfree(lc->disk_header);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700360 kfree(lc);
361 return -ENOMEM;
362 }
363 memset(lc->recovering_bits, 0, bitset_size);
364 lc->sync_search = 0;
365 log->context = lc;
Alasdair G Kergonb7cca192006-06-26 00:27:29 -0700366
Linus Torvalds1da177e2005-04-16 15:20:36 -0700367 return 0;
368}
369
Alasdair G Kergonb7cca192006-06-26 00:27:29 -0700370static int core_ctr(struct dirty_log *log, struct dm_target *ti,
371 unsigned int argc, char **argv)
372{
373 return create_log_context(log, ti, argc, argv, NULL);
374}
375
376static void destroy_log_context(struct log_c *lc)
377{
378 vfree(lc->sync_bits);
379 vfree(lc->recovering_bits);
380 kfree(lc);
381}
382
Linus Torvalds1da177e2005-04-16 15:20:36 -0700383static void core_dtr(struct dirty_log *log)
384{
385 struct log_c *lc = (struct log_c *) log->context;
Alasdair G Kergonb7cca192006-06-26 00:27:29 -0700386
Linus Torvalds1da177e2005-04-16 15:20:36 -0700387 vfree(lc->clean_bits);
Alasdair G Kergonb7cca192006-06-26 00:27:29 -0700388 destroy_log_context(lc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700389}
390
391/*----------------------------------------------------------------
392 * disk log constructor/destructor
393 *
394 * argv contains log_device region_size followed optionally by [no]sync
395 *--------------------------------------------------------------*/
396static int disk_ctr(struct dirty_log *log, struct dm_target *ti,
397 unsigned int argc, char **argv)
398{
399 int r;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700400 struct dm_dev *dev;
401
402 if (argc < 2 || argc > 3) {
403 DMWARN("wrong number of arguments to disk mirror log");
404 return -EINVAL;
405 }
406
407 r = dm_get_device(ti, argv[0], 0, 0 /* FIXME */,
408 FMODE_READ | FMODE_WRITE, &dev);
409 if (r)
410 return r;
411
Alasdair G Kergonb7cca192006-06-26 00:27:29 -0700412 r = create_log_context(log, ti, argc - 1, argv + 1, dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700413 if (r) {
414 dm_put_device(ti, dev);
415 return r;
416 }
417
Linus Torvalds1da177e2005-04-16 15:20:36 -0700418 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700419}
420
421static void disk_dtr(struct dirty_log *log)
422{
423 struct log_c *lc = (struct log_c *) log->context;
Alasdair G Kergonb7cca192006-06-26 00:27:29 -0700424
Linus Torvalds1da177e2005-04-16 15:20:36 -0700425 dm_put_device(lc->ti, lc->log_dev);
426 vfree(lc->disk_header);
Alasdair G Kergonb7cca192006-06-26 00:27:29 -0700427 destroy_log_context(lc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700428}
429
430static int count_bits32(uint32_t *addr, unsigned size)
431{
432 int count = 0, i;
433
434 for (i = 0; i < size; i++) {
435 count += hweight32(*(addr+i));
436 }
437 return count;
438}
439
440static int disk_resume(struct dirty_log *log)
441{
442 int r;
443 unsigned i;
444 struct log_c *lc = (struct log_c *) log->context;
445 size_t size = lc->bitset_uint32_count * sizeof(uint32_t);
446
447 /* read the disk header */
448 r = read_header(lc);
449 if (r)
450 return r;
451
Alasdair G Kergon8a835f12006-06-26 00:27:30 -0700452 /* set or clear any new bits -- device has grown */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700453 if (lc->sync == NOSYNC)
454 for (i = lc->header.nr_regions; i < lc->region_count; i++)
455 /* FIXME: amazingly inefficient */
456 log_set_bit(lc, lc->clean_bits, i);
457 else
458 for (i = lc->header.nr_regions; i < lc->region_count; i++)
459 /* FIXME: amazingly inefficient */
460 log_clear_bit(lc, lc->clean_bits, i);
461
Alasdair G Kergon8a835f12006-06-26 00:27:30 -0700462 /* clear any old bits -- device has shrunk */
463 for (i = lc->region_count; i % (sizeof(*lc->clean_bits) << BYTE_SHIFT); i++)
464 log_clear_bit(lc, lc->clean_bits, i);
465
Linus Torvalds1da177e2005-04-16 15:20:36 -0700466 /* copy clean across to sync */
467 memcpy(lc->sync_bits, lc->clean_bits, size);
468 lc->sync_count = count_bits32(lc->clean_bits, lc->bitset_uint32_count);
469
Linus Torvalds1da177e2005-04-16 15:20:36 -0700470 /* set the correct number of regions in the header */
471 lc->header.nr_regions = lc->region_count;
472
473 /* write the new header */
474 return write_header(lc);
475}
476
477static uint32_t core_get_region_size(struct dirty_log *log)
478{
479 struct log_c *lc = (struct log_c *) log->context;
480 return lc->region_size;
481}
482
483static int core_is_clean(struct dirty_log *log, region_t region)
484{
485 struct log_c *lc = (struct log_c *) log->context;
486 return log_test_bit(lc->clean_bits, region);
487}
488
489static int core_in_sync(struct dirty_log *log, region_t region, int block)
490{
491 struct log_c *lc = (struct log_c *) log->context;
492 return log_test_bit(lc->sync_bits, region);
493}
494
495static int core_flush(struct dirty_log *log)
496{
497 /* no op */
498 return 0;
499}
500
501static int disk_flush(struct dirty_log *log)
502{
503 int r;
504 struct log_c *lc = (struct log_c *) log->context;
505
506 /* only write if the log has changed */
507 if (!lc->touched)
508 return 0;
509
Kevin Corry702ca6f2006-06-26 00:27:28 -0700510 r = write_header(lc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700511 if (!r)
512 lc->touched = 0;
513
514 return r;
515}
516
517static void core_mark_region(struct dirty_log *log, region_t region)
518{
519 struct log_c *lc = (struct log_c *) log->context;
520 log_clear_bit(lc, lc->clean_bits, region);
521}
522
523static void core_clear_region(struct dirty_log *log, region_t region)
524{
525 struct log_c *lc = (struct log_c *) log->context;
526 log_set_bit(lc, lc->clean_bits, region);
527}
528
529static int core_get_resync_work(struct dirty_log *log, region_t *region)
530{
531 struct log_c *lc = (struct log_c *) log->context;
532
533 if (lc->sync_search >= lc->region_count)
534 return 0;
535
536 do {
Stefan Bader1113a7e2006-02-02 14:28:07 -0800537 *region = ext2_find_next_zero_bit(
538 (unsigned long *) lc->sync_bits,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700539 lc->region_count,
540 lc->sync_search);
541 lc->sync_search = *region + 1;
542
Darrick J. Wongac81b2e2006-01-06 00:20:11 -0800543 if (*region >= lc->region_count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700544 return 0;
545
546 } while (log_test_bit(lc->recovering_bits, *region));
547
548 log_set_bit(lc, lc->recovering_bits, *region);
549 return 1;
550}
551
552static void core_complete_resync_work(struct dirty_log *log, region_t region,
553 int success)
554{
555 struct log_c *lc = (struct log_c *) log->context;
556
557 log_clear_bit(lc, lc->recovering_bits, region);
558 if (success) {
559 log_set_bit(lc, lc->sync_bits, region);
560 lc->sync_count++;
561 }
562}
563
564static region_t core_get_sync_count(struct dirty_log *log)
565{
566 struct log_c *lc = (struct log_c *) log->context;
567
568 return lc->sync_count;
569}
570
571#define DMEMIT_SYNC \
572 if (lc->sync != DEFAULTSYNC) \
573 DMEMIT("%ssync ", lc->sync == NOSYNC ? "no" : "")
574
575static int core_status(struct dirty_log *log, status_type_t status,
576 char *result, unsigned int maxlen)
577{
578 int sz = 0;
579 struct log_c *lc = log->context;
580
581 switch(status) {
582 case STATUSTYPE_INFO:
583 break;
584
585 case STATUSTYPE_TABLE:
586 DMEMIT("%s %u %u ", log->type->name,
587 lc->sync == DEFAULTSYNC ? 1 : 2, lc->region_size);
588 DMEMIT_SYNC;
589 }
590
591 return sz;
592}
593
594static int disk_status(struct dirty_log *log, status_type_t status,
595 char *result, unsigned int maxlen)
596{
597 int sz = 0;
598 char buffer[16];
599 struct log_c *lc = log->context;
600
601 switch(status) {
602 case STATUSTYPE_INFO:
603 break;
604
605 case STATUSTYPE_TABLE:
606 format_dev_t(buffer, lc->log_dev->bdev->bd_dev);
607 DMEMIT("%s %u %s %u ", log->type->name,
608 lc->sync == DEFAULTSYNC ? 2 : 3, buffer,
609 lc->region_size);
610 DMEMIT_SYNC;
611 }
612
613 return sz;
614}
615
616static struct dirty_log_type _core_type = {
617 .name = "core",
618 .module = THIS_MODULE,
619 .ctr = core_ctr,
620 .dtr = core_dtr,
621 .get_region_size = core_get_region_size,
622 .is_clean = core_is_clean,
623 .in_sync = core_in_sync,
624 .flush = core_flush,
625 .mark_region = core_mark_region,
626 .clear_region = core_clear_region,
627 .get_resync_work = core_get_resync_work,
628 .complete_resync_work = core_complete_resync_work,
629 .get_sync_count = core_get_sync_count,
630 .status = core_status,
631};
632
633static struct dirty_log_type _disk_type = {
634 .name = "disk",
635 .module = THIS_MODULE,
636 .ctr = disk_ctr,
637 .dtr = disk_dtr,
638 .suspend = disk_flush,
639 .resume = disk_resume,
640 .get_region_size = core_get_region_size,
641 .is_clean = core_is_clean,
642 .in_sync = core_in_sync,
643 .flush = disk_flush,
644 .mark_region = core_mark_region,
645 .clear_region = core_clear_region,
646 .get_resync_work = core_get_resync_work,
647 .complete_resync_work = core_complete_resync_work,
648 .get_sync_count = core_get_sync_count,
649 .status = disk_status,
650};
651
652int __init dm_dirty_log_init(void)
653{
654 int r;
655
656 r = dm_register_dirty_log_type(&_core_type);
657 if (r)
658 DMWARN("couldn't register core log");
659
660 r = dm_register_dirty_log_type(&_disk_type);
661 if (r) {
662 DMWARN("couldn't register disk type");
663 dm_unregister_dirty_log_type(&_core_type);
664 }
665
666 return r;
667}
668
669void dm_dirty_log_exit(void)
670{
671 dm_unregister_dirty_log_type(&_disk_type);
672 dm_unregister_dirty_log_type(&_core_type);
673}
674
675EXPORT_SYMBOL(dm_register_dirty_log_type);
676EXPORT_SYMBOL(dm_unregister_dirty_log_type);
677EXPORT_SYMBOL(dm_create_dirty_log);
678EXPORT_SYMBOL(dm_destroy_dirty_log);