2
* Copyright (C) 2003 Sistina Software
3
* Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
5
* This file is released under the LGPL.
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>
15
#include <linux/device-mapper.h>
17
#define DM_MSG_PREFIX "dirty region log"
19
static LIST_HEAD(_log_types);
20
static DEFINE_SPINLOCK(_lock);
22
static struct dm_dirty_log_type *__find_dirty_log_type(const char *name)
24
struct dm_dirty_log_type *log_type;
26
list_for_each_entry(log_type, &_log_types, list)
27
if (!strcmp(name, log_type->name))
33
static struct dm_dirty_log_type *_get_dirty_log_type(const char *name)
35
struct dm_dirty_log_type *log_type;
39
log_type = __find_dirty_log_type(name);
40
if (log_type && !try_module_get(log_type->module))
52
* Attempt to retrieve the dm_dirty_log_type by name. If not already
53
* available, attempt to load the appropriate module.
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.
60
* For example, if type_name was "clustered-disk", it would search
61
* 'dm-log-clustered-disk' then 'dm-log-clustered'.
63
* Returns: dirty_log_type* on success, NULL on failure
65
static struct dm_dirty_log_type *get_type(const char *type_name)
67
char *p, *type_name_dup;
68
struct dm_dirty_log_type *log_type;
73
log_type = _get_dirty_log_type(type_name);
77
type_name_dup = kstrdup(type_name, GFP_KERNEL);
79
DMWARN("No memory left to attempt log module load for \"%s\"",
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, '-');
93
DMWARN("Module for logging type \"%s\" not found.", type_name);
100
static void put_type(struct dm_dirty_log_type *type)
106
if (!__find_dirty_log_type(type->name))
109
module_put(type->module);
115
int dm_dirty_log_type_register(struct dm_dirty_log_type *type)
120
if (!__find_dirty_log_type(type->name))
121
list_add(&type->list, &_log_types);
128
EXPORT_SYMBOL(dm_dirty_log_type_register);
130
int dm_dirty_log_type_unregister(struct dm_dirty_log_type *type)
134
if (!__find_dirty_log_type(type->name)) {
139
list_del(&type->list);
145
EXPORT_SYMBOL(dm_dirty_log_type_unregister);
147
struct dm_dirty_log *dm_dirty_log_create(const char *type_name,
148
struct dm_target *ti,
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int (*flush_callback_fn)(struct dm_target *ti),
150
unsigned int argc, char **argv)
152
struct dm_dirty_log_type *type;
153
struct dm_dirty_log *log;
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log = kmalloc(sizeof(*log), GFP_KERNEL);
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type = get_type(type_name);
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log->flush_callback_fn = flush_callback_fn;
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if (type->ctr(log, ti, argc, argv)) {
175
EXPORT_SYMBOL(dm_dirty_log_create);
177
void dm_dirty_log_destroy(struct dm_dirty_log *log)
183
EXPORT_SYMBOL(dm_dirty_log_destroy);
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/*-----------------------------------------------------------------
186
* Persistent and core logs share a lot of their implementation.
187
* FIXME: need a reload method to be called from a resume
188
*---------------------------------------------------------------*/
190
* Magic for persistent mirrors: "MiRr"
192
#define MIRROR_MAGIC 0x4D695272
195
* The on-disk version of the metadata.
197
#define MIRROR_DISK_VERSION 2
200
struct log_header_disk {
204
* Simple, incrementing version. no backward
211
struct log_header_core {
218
struct dm_target *ti;
222
uint32_t region_size;
223
unsigned int region_count;
226
unsigned bitset_uint32_count;
227
uint32_t *clean_bits;
229
uint32_t *recovering_bits; /* FIXME: this seems excessive */
235
DEFAULTSYNC, /* Synchronize if necessary */
236
NOSYNC, /* Devices known to be already in sync */
237
FORCESYNC, /* Force a sync to happen */
240
struct dm_io_request io_req;
246
int log_dev_flush_failed;
247
struct dm_dev *log_dev;
248
struct log_header_core header;
250
struct dm_io_region header_location;
251
struct log_header_disk *disk_header;
255
* The touched member needs to be updated every time we access
256
* one of the bitsets.
258
static inline int log_test_bit(uint32_t *bs, unsigned bit)
260
return test_bit_le(bit, bs) ? 1 : 0;
263
static inline void log_set_bit(struct log_c *l,
264
uint32_t *bs, unsigned bit)
266
__set_bit_le(bit, bs);
267
l->touched_cleaned = 1;
270
static inline void log_clear_bit(struct log_c *l,
271
uint32_t *bs, unsigned bit)
273
__clear_bit_le(bit, bs);
274
l->touched_dirtied = 1;
277
/*----------------------------------------------------------------
279
*--------------------------------------------------------------*/
280
static void header_to_disk(struct log_header_core *core, struct log_header_disk *disk)
282
disk->magic = cpu_to_le32(core->magic);
283
disk->version = cpu_to_le32(core->version);
284
disk->nr_regions = cpu_to_le64(core->nr_regions);
287
static void header_from_disk(struct log_header_core *core, struct log_header_disk *disk)
289
core->magic = le32_to_cpu(disk->magic);
290
core->version = le32_to_cpu(disk->version);
291
core->nr_regions = le64_to_cpu(disk->nr_regions);
294
static int rw_header(struct log_c *lc, int rw)
296
lc->io_req.bi_rw = rw;
298
return dm_io(&lc->io_req, 1, &lc->header_location, NULL);
301
static int flush_header(struct log_c *lc)
303
struct dm_io_region null_location = {
304
.bdev = lc->header_location.bdev,
309
lc->io_req.bi_rw = WRITE_FLUSH;
311
return dm_io(&lc->io_req, 1, &null_location, NULL);
314
static int read_header(struct log_c *log)
318
r = rw_header(log, READ);
322
header_from_disk(&log->header, log->disk_header);
324
/* New log required? */
325
if (log->sync != DEFAULTSYNC || log->header.magic != MIRROR_MAGIC) {
326
log->header.magic = MIRROR_MAGIC;
327
log->header.version = MIRROR_DISK_VERSION;
328
log->header.nr_regions = 0;
331
#ifdef __LITTLE_ENDIAN
332
if (log->header.version == 1)
333
log->header.version = 2;
336
if (log->header.version != MIRROR_DISK_VERSION) {
337
DMWARN("incompatible disk log version");
344
static int _check_region_size(struct dm_target *ti, uint32_t region_size)
346
if (region_size < 2 || region_size > ti->len)
349
if (!is_power_of_2(region_size))
355
/*----------------------------------------------------------------
356
* core log constructor/destructor
358
* argv contains region_size followed optionally by [no]sync
359
*--------------------------------------------------------------*/
361
static int create_log_context(struct dm_dirty_log *log, struct dm_target *ti,
362
unsigned int argc, char **argv,
365
enum sync sync = DEFAULTSYNC;
368
uint32_t region_size;
369
unsigned int region_count;
370
size_t bitset_size, buf_size;
373
if (argc < 1 || argc > 2) {
374
DMWARN("wrong number of arguments to dirty region log");
379
if (!strcmp(argv[1], "sync"))
381
else if (!strcmp(argv[1], "nosync"))
384
DMWARN("unrecognised sync argument to "
385
"dirty region log: %s", argv[1]);
390
if (sscanf(argv[0], "%u", ®ion_size) != 1 ||
391
!_check_region_size(ti, region_size)) {
392
DMWARN("invalid region size %s", argv[0]);
396
region_count = dm_sector_div_up(ti->len, region_size);
398
lc = kmalloc(sizeof(*lc), GFP_KERNEL);
400
DMWARN("couldn't allocate core log");
405
lc->touched_dirtied = 0;
406
lc->touched_cleaned = 0;
407
lc->flush_failed = 0;
408
lc->region_size = region_size;
409
lc->region_count = region_count;
413
* Work out how many "unsigned long"s we need to hold the bitset.
415
bitset_size = dm_round_up(region_count,
416
sizeof(*lc->clean_bits) << BYTE_SHIFT);
417
bitset_size >>= BYTE_SHIFT;
419
lc->bitset_uint32_count = bitset_size / sizeof(*lc->clean_bits);
425
lc->clean_bits = vmalloc(bitset_size);
426
if (!lc->clean_bits) {
427
DMWARN("couldn't allocate clean bitset");
431
lc->disk_header = NULL;
434
lc->log_dev_failed = 0;
435
lc->log_dev_flush_failed = 0;
436
lc->header_location.bdev = lc->log_dev->bdev;
437
lc->header_location.sector = 0;
440
* Buffer holds both header and bitset.
443
dm_round_up((LOG_OFFSET << SECTOR_SHIFT) + bitset_size,
444
bdev_logical_block_size(lc->header_location.
447
if (buf_size > i_size_read(dev->bdev->bd_inode)) {
448
DMWARN("log device %s too small: need %llu bytes",
449
dev->name, (unsigned long long)buf_size);
454
lc->header_location.count = buf_size >> SECTOR_SHIFT;
456
lc->io_req.mem.type = DM_IO_VMA;
457
lc->io_req.notify.fn = NULL;
458
lc->io_req.client = dm_io_client_create();
459
if (IS_ERR(lc->io_req.client)) {
460
r = PTR_ERR(lc->io_req.client);
461
DMWARN("couldn't allocate disk io client");
466
lc->disk_header = vmalloc(buf_size);
467
if (!lc->disk_header) {
468
DMWARN("couldn't allocate disk log buffer");
469
dm_io_client_destroy(lc->io_req.client);
474
lc->io_req.mem.ptr.vma = lc->disk_header;
475
lc->clean_bits = (void *)lc->disk_header +
476
(LOG_OFFSET << SECTOR_SHIFT);
479
memset(lc->clean_bits, -1, bitset_size);
481
lc->sync_bits = vmalloc(bitset_size);
482
if (!lc->sync_bits) {
483
DMWARN("couldn't allocate sync bitset");
485
vfree(lc->clean_bits);
487
dm_io_client_destroy(lc->io_req.client);
488
vfree(lc->disk_header);
492
memset(lc->sync_bits, (sync == NOSYNC) ? -1 : 0, bitset_size);
493
lc->sync_count = (sync == NOSYNC) ? region_count : 0;
495
lc->recovering_bits = vzalloc(bitset_size);
496
if (!lc->recovering_bits) {
497
DMWARN("couldn't allocate sync bitset");
498
vfree(lc->sync_bits);
500
vfree(lc->clean_bits);
502
dm_io_client_destroy(lc->io_req.client);
503
vfree(lc->disk_header);
513
static int core_ctr(struct dm_dirty_log *log, struct dm_target *ti,
514
unsigned int argc, char **argv)
516
return create_log_context(log, ti, argc, argv, NULL);
519
static void destroy_log_context(struct log_c *lc)
521
vfree(lc->sync_bits);
522
vfree(lc->recovering_bits);
526
static void core_dtr(struct dm_dirty_log *log)
528
struct log_c *lc = (struct log_c *) log->context;
530
vfree(lc->clean_bits);
531
destroy_log_context(lc);
534
/*----------------------------------------------------------------
535
* disk log constructor/destructor
537
* argv contains log_device region_size followed optionally by [no]sync
538
*--------------------------------------------------------------*/
539
static int disk_ctr(struct dm_dirty_log *log, struct dm_target *ti,
540
unsigned int argc, char **argv)
545
if (argc < 2 || argc > 3) {
546
DMWARN("wrong number of arguments to disk dirty region log");
550
r = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &dev);
554
r = create_log_context(log, ti, argc - 1, argv + 1, dev);
556
dm_put_device(ti, dev);
563
static void disk_dtr(struct dm_dirty_log *log)
565
struct log_c *lc = (struct log_c *) log->context;
567
dm_put_device(lc->ti, lc->log_dev);
568
vfree(lc->disk_header);
569
dm_io_client_destroy(lc->io_req.client);
570
destroy_log_context(lc);
573
static int count_bits32(uint32_t *addr, unsigned size)
577
for (i = 0; i < size; i++) {
578
count += hweight32(*(addr+i));
583
static void fail_log_device(struct log_c *lc)
585
if (lc->log_dev_failed)
588
lc->log_dev_failed = 1;
589
dm_table_event(lc->ti->table);
592
static int disk_resume(struct dm_dirty_log *log)
596
struct log_c *lc = (struct log_c *) log->context;
597
size_t size = lc->bitset_uint32_count * sizeof(uint32_t);
599
/* read the disk header */
602
DMWARN("%s: Failed to read header on dirty region log device",
606
* If the log device cannot be read, we must assume
607
* all regions are out-of-sync. If we simply return
608
* here, the state will be uninitialized and could
609
* lead us to return 'in-sync' status for regions
610
* that are actually 'out-of-sync'.
612
lc->header.nr_regions = 0;
615
/* set or clear any new bits -- device has grown */
616
if (lc->sync == NOSYNC)
617
for (i = lc->header.nr_regions; i < lc->region_count; i++)
618
/* FIXME: amazingly inefficient */
619
log_set_bit(lc, lc->clean_bits, i);
621
for (i = lc->header.nr_regions; i < lc->region_count; i++)
622
/* FIXME: amazingly inefficient */
623
log_clear_bit(lc, lc->clean_bits, i);
625
/* clear any old bits -- device has shrunk */
626
for (i = lc->region_count; i % (sizeof(*lc->clean_bits) << BYTE_SHIFT); i++)
627
log_clear_bit(lc, lc->clean_bits, i);
629
/* copy clean across to sync */
630
memcpy(lc->sync_bits, lc->clean_bits, size);
631
lc->sync_count = count_bits32(lc->clean_bits, lc->bitset_uint32_count);
634
/* set the correct number of regions in the header */
635
lc->header.nr_regions = lc->region_count;
637
header_to_disk(&lc->header, lc->disk_header);
639
/* write the new header */
640
r = rw_header(lc, WRITE);
642
r = flush_header(lc);
644
lc->log_dev_flush_failed = 1;
647
DMWARN("%s: Failed to write header on dirty region log device",
655
static uint32_t core_get_region_size(struct dm_dirty_log *log)
657
struct log_c *lc = (struct log_c *) log->context;
658
return lc->region_size;
661
static int core_resume(struct dm_dirty_log *log)
663
struct log_c *lc = (struct log_c *) log->context;
668
static int core_is_clean(struct dm_dirty_log *log, region_t region)
670
struct log_c *lc = (struct log_c *) log->context;
671
return log_test_bit(lc->clean_bits, region);
674
static int core_in_sync(struct dm_dirty_log *log, region_t region, int block)
676
struct log_c *lc = (struct log_c *) log->context;
677
return log_test_bit(lc->sync_bits, region);
680
static int core_flush(struct dm_dirty_log *log)
686
static int disk_flush(struct dm_dirty_log *log)
689
struct log_c *lc = log->context;
691
/* only write if the log has changed */
692
if (!lc->touched_cleaned && !lc->touched_dirtied)
695
if (lc->touched_cleaned && log->flush_callback_fn &&
696
log->flush_callback_fn(lc->ti)) {
698
* At this point it is impossible to determine which
699
* regions are clean and which are dirty (without
700
* re-reading the log off disk). So mark all of them
703
lc->flush_failed = 1;
704
for (i = 0; i < lc->region_count; i++)
705
log_clear_bit(lc, lc->clean_bits, i);
708
r = rw_header(lc, WRITE);
712
if (lc->touched_dirtied) {
713
r = flush_header(lc);
715
lc->log_dev_flush_failed = 1;
718
lc->touched_dirtied = 0;
720
lc->touched_cleaned = 0;
726
static void core_mark_region(struct dm_dirty_log *log, region_t region)
728
struct log_c *lc = (struct log_c *) log->context;
729
log_clear_bit(lc, lc->clean_bits, region);
732
static void core_clear_region(struct dm_dirty_log *log, region_t region)
734
struct log_c *lc = (struct log_c *) log->context;
735
if (likely(!lc->flush_failed))
736
log_set_bit(lc, lc->clean_bits, region);
739
static int core_get_resync_work(struct dm_dirty_log *log, region_t *region)
741
struct log_c *lc = (struct log_c *) log->context;
743
if (lc->sync_search >= lc->region_count)
747
*region = find_next_zero_bit_le(lc->sync_bits,
750
lc->sync_search = *region + 1;
752
if (*region >= lc->region_count)
755
} while (log_test_bit(lc->recovering_bits, *region));
757
log_set_bit(lc, lc->recovering_bits, *region);
761
static void core_set_region_sync(struct dm_dirty_log *log, region_t region,
764
struct log_c *lc = (struct log_c *) log->context;
766
log_clear_bit(lc, lc->recovering_bits, region);
768
log_set_bit(lc, lc->sync_bits, region);
770
} else if (log_test_bit(lc->sync_bits, region)) {
772
log_clear_bit(lc, lc->sync_bits, region);
776
static region_t core_get_sync_count(struct dm_dirty_log *log)
778
struct log_c *lc = (struct log_c *) log->context;
780
return lc->sync_count;
783
#define DMEMIT_SYNC \
784
if (lc->sync != DEFAULTSYNC) \
785
DMEMIT("%ssync ", lc->sync == NOSYNC ? "no" : "")
787
static int core_status(struct dm_dirty_log *log, status_type_t status,
788
char *result, unsigned int maxlen)
791
struct log_c *lc = log->context;
794
case STATUSTYPE_INFO:
795
DMEMIT("1 %s", log->type->name);
798
case STATUSTYPE_TABLE:
799
DMEMIT("%s %u %u ", log->type->name,
800
lc->sync == DEFAULTSYNC ? 1 : 2, lc->region_size);
807
static int disk_status(struct dm_dirty_log *log, status_type_t status,
808
char *result, unsigned int maxlen)
811
struct log_c *lc = log->context;
814
case STATUSTYPE_INFO:
815
DMEMIT("3 %s %s %c", log->type->name, lc->log_dev->name,
816
lc->log_dev_flush_failed ? 'F' :
817
lc->log_dev_failed ? 'D' :
821
case STATUSTYPE_TABLE:
822
DMEMIT("%s %u %s %u ", log->type->name,
823
lc->sync == DEFAULTSYNC ? 2 : 3, lc->log_dev->name,
831
static struct dm_dirty_log_type _core_type = {
833
.module = THIS_MODULE,
836
.resume = core_resume,
837
.get_region_size = core_get_region_size,
838
.is_clean = core_is_clean,
839
.in_sync = core_in_sync,
841
.mark_region = core_mark_region,
842
.clear_region = core_clear_region,
843
.get_resync_work = core_get_resync_work,
844
.set_region_sync = core_set_region_sync,
845
.get_sync_count = core_get_sync_count,
846
.status = core_status,
849
static struct dm_dirty_log_type _disk_type = {
851
.module = THIS_MODULE,
854
.postsuspend = disk_flush,
855
.resume = disk_resume,
856
.get_region_size = core_get_region_size,
857
.is_clean = core_is_clean,
858
.in_sync = core_in_sync,
860
.mark_region = core_mark_region,
861
.clear_region = core_clear_region,
862
.get_resync_work = core_get_resync_work,
863
.set_region_sync = core_set_region_sync,
864
.get_sync_count = core_get_sync_count,
865
.status = disk_status,
868
static int __init dm_dirty_log_init(void)
872
r = dm_dirty_log_type_register(&_core_type);
874
DMWARN("couldn't register core log");
876
r = dm_dirty_log_type_register(&_disk_type);
878
DMWARN("couldn't register disk type");
879
dm_dirty_log_type_unregister(&_core_type);
885
static void __exit dm_dirty_log_exit(void)
887
dm_dirty_log_type_unregister(&_disk_type);
888
dm_dirty_log_type_unregister(&_core_type);
891
module_init(dm_dirty_log_init);
892
module_exit(dm_dirty_log_exit);
894
MODULE_DESCRIPTION(DM_NAME " dirty region log");
895
MODULE_AUTHOR("Joe Thornber, Heinz Mauelshagen <dm-devel@redhat.com>");
896
MODULE_LICENSE("GPL");