linux/drivers/md/dm-log.c
Linus Torvalds 1da177e4c3 Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!
2005-04-16 15:20:36 -07:00

711 lines
16 KiB
C

/*
* Copyright (C) 2003 Sistina Software
*
* This file is released under the LGPL.
*/
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/vmalloc.h>
#include "dm-log.h"
#include "dm-io.h"
static LIST_HEAD(_log_types);
static DEFINE_SPINLOCK(_lock);
int dm_register_dirty_log_type(struct dirty_log_type *type)
{
spin_lock(&_lock);
type->use_count = 0;
list_add(&type->list, &_log_types);
spin_unlock(&_lock);
return 0;
}
int dm_unregister_dirty_log_type(struct dirty_log_type *type)
{
spin_lock(&_lock);
if (type->use_count)
DMWARN("Attempt to unregister a log type that is still in use");
else
list_del(&type->list);
spin_unlock(&_lock);
return 0;
}
static struct dirty_log_type *get_type(const char *type_name)
{
struct dirty_log_type *type;
spin_lock(&_lock);
list_for_each_entry (type, &_log_types, list)
if (!strcmp(type_name, type->name)) {
if (!type->use_count && !try_module_get(type->module)){
spin_unlock(&_lock);
return NULL;
}
type->use_count++;
spin_unlock(&_lock);
return type;
}
spin_unlock(&_lock);
return NULL;
}
static void put_type(struct dirty_log_type *type)
{
spin_lock(&_lock);
if (!--type->use_count)
module_put(type->module);
spin_unlock(&_lock);
}
struct dirty_log *dm_create_dirty_log(const char *type_name, struct dm_target *ti,
unsigned int argc, char **argv)
{
struct dirty_log_type *type;
struct dirty_log *log;
log = kmalloc(sizeof(*log), GFP_KERNEL);
if (!log)
return NULL;
type = get_type(type_name);
if (!type) {
kfree(log);
return NULL;
}
log->type = type;
if (type->ctr(log, ti, argc, argv)) {
kfree(log);
put_type(type);
return NULL;
}
return log;
}
void dm_destroy_dirty_log(struct dirty_log *log)
{
log->type->dtr(log);
put_type(log->type);
kfree(log);
}
/*-----------------------------------------------------------------
* Persistent and core logs share a lot of their implementation.
* FIXME: need a reload method to be called from a resume
*---------------------------------------------------------------*/
/*
* Magic for persistent mirrors: "MiRr"
*/
#define MIRROR_MAGIC 0x4D695272
/*
* The on-disk version of the metadata.
*/
#define MIRROR_DISK_VERSION 1
#define LOG_OFFSET 2
struct log_header {
uint32_t magic;
/*
* Simple, incrementing version. no backward
* compatibility.
*/
uint32_t version;
sector_t nr_regions;
};
struct log_c {
struct dm_target *ti;
int touched;
uint32_t region_size;
unsigned int region_count;
region_t sync_count;
unsigned bitset_uint32_count;
uint32_t *clean_bits;
uint32_t *sync_bits;
uint32_t *recovering_bits; /* FIXME: this seems excessive */
int sync_search;
/* Resync flag */
enum sync {
DEFAULTSYNC, /* Synchronize if necessary */
NOSYNC, /* Devices known to be already in sync */
FORCESYNC, /* Force a sync to happen */
} sync;
/*
* Disk log fields
*/
struct dm_dev *log_dev;
struct log_header header;
struct io_region header_location;
struct log_header *disk_header;
struct io_region bits_location;
uint32_t *disk_bits;
};
/*
* The touched member needs to be updated every time we access
* one of the bitsets.
*/
static inline int log_test_bit(uint32_t *bs, unsigned bit)
{
return test_bit(bit, (unsigned long *) bs) ? 1 : 0;
}
static inline void log_set_bit(struct log_c *l,
uint32_t *bs, unsigned bit)
{
set_bit(bit, (unsigned long *) bs);
l->touched = 1;
}
static inline void log_clear_bit(struct log_c *l,
uint32_t *bs, unsigned bit)
{
clear_bit(bit, (unsigned long *) bs);
l->touched = 1;
}
/*----------------------------------------------------------------
* Header IO
*--------------------------------------------------------------*/
static void header_to_disk(struct log_header *core, struct log_header *disk)
{
disk->magic = cpu_to_le32(core->magic);
disk->version = cpu_to_le32(core->version);
disk->nr_regions = cpu_to_le64(core->nr_regions);
}
static void header_from_disk(struct log_header *core, struct log_header *disk)
{
core->magic = le32_to_cpu(disk->magic);
core->version = le32_to_cpu(disk->version);
core->nr_regions = le64_to_cpu(disk->nr_regions);
}
static int read_header(struct log_c *log)
{
int r;
unsigned long ebits;
r = dm_io_sync_vm(1, &log->header_location, READ,
log->disk_header, &ebits);
if (r)
return r;
header_from_disk(&log->header, log->disk_header);
/* New log required? */
if (log->sync != DEFAULTSYNC || log->header.magic != MIRROR_MAGIC) {
log->header.magic = MIRROR_MAGIC;
log->header.version = MIRROR_DISK_VERSION;
log->header.nr_regions = 0;
}
if (log->header.version != MIRROR_DISK_VERSION) {
DMWARN("incompatible disk log version");
return -EINVAL;
}
return 0;
}
static inline int write_header(struct log_c *log)
{
unsigned long ebits;
header_to_disk(&log->header, log->disk_header);
return dm_io_sync_vm(1, &log->header_location, WRITE,
log->disk_header, &ebits);
}
/*----------------------------------------------------------------
* Bits IO
*--------------------------------------------------------------*/
static inline void bits_to_core(uint32_t *core, uint32_t *disk, unsigned count)
{
unsigned i;
for (i = 0; i < count; i++)
core[i] = le32_to_cpu(disk[i]);
}
static inline void bits_to_disk(uint32_t *core, uint32_t *disk, unsigned count)
{
unsigned i;
/* copy across the clean/dirty bitset */
for (i = 0; i < count; i++)
disk[i] = cpu_to_le32(core[i]);
}
static int read_bits(struct log_c *log)
{
int r;
unsigned long ebits;
r = dm_io_sync_vm(1, &log->bits_location, READ,
log->disk_bits, &ebits);
if (r)
return r;
bits_to_core(log->clean_bits, log->disk_bits,
log->bitset_uint32_count);
return 0;
}
static int write_bits(struct log_c *log)
{
unsigned long ebits;
bits_to_disk(log->clean_bits, log->disk_bits,
log->bitset_uint32_count);
return dm_io_sync_vm(1, &log->bits_location, WRITE,
log->disk_bits, &ebits);
}
/*----------------------------------------------------------------
* core log constructor/destructor
*
* argv contains region_size followed optionally by [no]sync
*--------------------------------------------------------------*/
#define BYTE_SHIFT 3
static int core_ctr(struct dirty_log *log, struct dm_target *ti,
unsigned int argc, char **argv)
{
enum sync sync = DEFAULTSYNC;
struct log_c *lc;
uint32_t region_size;
unsigned int region_count;
size_t bitset_size;
if (argc < 1 || argc > 2) {
DMWARN("wrong number of arguments to mirror log");
return -EINVAL;
}
if (argc > 1) {
if (!strcmp(argv[1], "sync"))
sync = FORCESYNC;
else if (!strcmp(argv[1], "nosync"))
sync = NOSYNC;
else {
DMWARN("unrecognised sync argument to mirror log: %s",
argv[1]);
return -EINVAL;
}
}
if (sscanf(argv[0], "%u", &region_size) != 1) {
DMWARN("invalid region size string");
return -EINVAL;
}
region_count = dm_sector_div_up(ti->len, region_size);
lc = kmalloc(sizeof(*lc), GFP_KERNEL);
if (!lc) {
DMWARN("couldn't allocate core log");
return -ENOMEM;
}
lc->ti = ti;
lc->touched = 0;
lc->region_size = region_size;
lc->region_count = region_count;
lc->sync = sync;
/*
* Work out how many words we need to hold the bitset.
*/
bitset_size = dm_round_up(region_count,
sizeof(*lc->clean_bits) << BYTE_SHIFT);
bitset_size >>= BYTE_SHIFT;
lc->bitset_uint32_count = bitset_size / 4;
lc->clean_bits = vmalloc(bitset_size);
if (!lc->clean_bits) {
DMWARN("couldn't allocate clean bitset");
kfree(lc);
return -ENOMEM;
}
memset(lc->clean_bits, -1, bitset_size);
lc->sync_bits = vmalloc(bitset_size);
if (!lc->sync_bits) {
DMWARN("couldn't allocate sync bitset");
vfree(lc->clean_bits);
kfree(lc);
return -ENOMEM;
}
memset(lc->sync_bits, (sync == NOSYNC) ? -1 : 0, bitset_size);
lc->sync_count = (sync == NOSYNC) ? region_count : 0;
lc->recovering_bits = vmalloc(bitset_size);
if (!lc->recovering_bits) {
DMWARN("couldn't allocate sync bitset");
vfree(lc->sync_bits);
vfree(lc->clean_bits);
kfree(lc);
return -ENOMEM;
}
memset(lc->recovering_bits, 0, bitset_size);
lc->sync_search = 0;
log->context = lc;
return 0;
}
static void core_dtr(struct dirty_log *log)
{
struct log_c *lc = (struct log_c *) log->context;
vfree(lc->clean_bits);
vfree(lc->sync_bits);
vfree(lc->recovering_bits);
kfree(lc);
}
/*----------------------------------------------------------------
* disk log constructor/destructor
*
* argv contains log_device region_size followed optionally by [no]sync
*--------------------------------------------------------------*/
static int disk_ctr(struct dirty_log *log, struct dm_target *ti,
unsigned int argc, char **argv)
{
int r;
size_t size;
struct log_c *lc;
struct dm_dev *dev;
if (argc < 2 || argc > 3) {
DMWARN("wrong number of arguments to disk mirror log");
return -EINVAL;
}
r = dm_get_device(ti, argv[0], 0, 0 /* FIXME */,
FMODE_READ | FMODE_WRITE, &dev);
if (r)
return r;
r = core_ctr(log, ti, argc - 1, argv + 1);
if (r) {
dm_put_device(ti, dev);
return r;
}
lc = (struct log_c *) log->context;
lc->log_dev = dev;
/* setup the disk header fields */
lc->header_location.bdev = lc->log_dev->bdev;
lc->header_location.sector = 0;
lc->header_location.count = 1;
/*
* We can't read less than this amount, even though we'll
* not be using most of this space.
*/
lc->disk_header = vmalloc(1 << SECTOR_SHIFT);
if (!lc->disk_header)
goto bad;
/* setup the disk bitset fields */
lc->bits_location.bdev = lc->log_dev->bdev;
lc->bits_location.sector = LOG_OFFSET;
size = dm_round_up(lc->bitset_uint32_count * sizeof(uint32_t),
1 << SECTOR_SHIFT);
lc->bits_location.count = size >> SECTOR_SHIFT;
lc->disk_bits = vmalloc(size);
if (!lc->disk_bits) {
vfree(lc->disk_header);
goto bad;
}
return 0;
bad:
dm_put_device(ti, lc->log_dev);
core_dtr(log);
return -ENOMEM;
}
static void disk_dtr(struct dirty_log *log)
{
struct log_c *lc = (struct log_c *) log->context;
dm_put_device(lc->ti, lc->log_dev);
vfree(lc->disk_header);
vfree(lc->disk_bits);
core_dtr(log);
}
static int count_bits32(uint32_t *addr, unsigned size)
{
int count = 0, i;
for (i = 0; i < size; i++) {
count += hweight32(*(addr+i));
}
return count;
}
static int disk_resume(struct dirty_log *log)
{
int r;
unsigned i;
struct log_c *lc = (struct log_c *) log->context;
size_t size = lc->bitset_uint32_count * sizeof(uint32_t);
/* read the disk header */
r = read_header(lc);
if (r)
return r;
/* read the bits */
r = read_bits(lc);
if (r)
return r;
/* set or clear any new bits */
if (lc->sync == NOSYNC)
for (i = lc->header.nr_regions; i < lc->region_count; i++)
/* FIXME: amazingly inefficient */
log_set_bit(lc, lc->clean_bits, i);
else
for (i = lc->header.nr_regions; i < lc->region_count; i++)
/* FIXME: amazingly inefficient */
log_clear_bit(lc, lc->clean_bits, i);
/* copy clean across to sync */
memcpy(lc->sync_bits, lc->clean_bits, size);
lc->sync_count = count_bits32(lc->clean_bits, lc->bitset_uint32_count);
/* write the bits */
r = write_bits(lc);
if (r)
return r;
/* set the correct number of regions in the header */
lc->header.nr_regions = lc->region_count;
/* write the new header */
return write_header(lc);
}
static uint32_t core_get_region_size(struct dirty_log *log)
{
struct log_c *lc = (struct log_c *) log->context;
return lc->region_size;
}
static int core_is_clean(struct dirty_log *log, region_t region)
{
struct log_c *lc = (struct log_c *) log->context;
return log_test_bit(lc->clean_bits, region);
}
static int core_in_sync(struct dirty_log *log, region_t region, int block)
{
struct log_c *lc = (struct log_c *) log->context;
return log_test_bit(lc->sync_bits, region);
}
static int core_flush(struct dirty_log *log)
{
/* no op */
return 0;
}
static int disk_flush(struct dirty_log *log)
{
int r;
struct log_c *lc = (struct log_c *) log->context;
/* only write if the log has changed */
if (!lc->touched)
return 0;
r = write_bits(lc);
if (!r)
lc->touched = 0;
return r;
}
static void core_mark_region(struct dirty_log *log, region_t region)
{
struct log_c *lc = (struct log_c *) log->context;
log_clear_bit(lc, lc->clean_bits, region);
}
static void core_clear_region(struct dirty_log *log, region_t region)
{
struct log_c *lc = (struct log_c *) log->context;
log_set_bit(lc, lc->clean_bits, region);
}
static int core_get_resync_work(struct dirty_log *log, region_t *region)
{
struct log_c *lc = (struct log_c *) log->context;
if (lc->sync_search >= lc->region_count)
return 0;
do {
*region = find_next_zero_bit((unsigned long *) lc->sync_bits,
lc->region_count,
lc->sync_search);
lc->sync_search = *region + 1;
if (*region == lc->region_count)
return 0;
} while (log_test_bit(lc->recovering_bits, *region));
log_set_bit(lc, lc->recovering_bits, *region);
return 1;
}
static void core_complete_resync_work(struct dirty_log *log, region_t region,
int success)
{
struct log_c *lc = (struct log_c *) log->context;
log_clear_bit(lc, lc->recovering_bits, region);
if (success) {
log_set_bit(lc, lc->sync_bits, region);
lc->sync_count++;
}
}
static region_t core_get_sync_count(struct dirty_log *log)
{
struct log_c *lc = (struct log_c *) log->context;
return lc->sync_count;
}
#define DMEMIT_SYNC \
if (lc->sync != DEFAULTSYNC) \
DMEMIT("%ssync ", lc->sync == NOSYNC ? "no" : "")
static int core_status(struct dirty_log *log, status_type_t status,
char *result, unsigned int maxlen)
{
int sz = 0;
struct log_c *lc = log->context;
switch(status) {
case STATUSTYPE_INFO:
break;
case STATUSTYPE_TABLE:
DMEMIT("%s %u %u ", log->type->name,
lc->sync == DEFAULTSYNC ? 1 : 2, lc->region_size);
DMEMIT_SYNC;
}
return sz;
}
static int disk_status(struct dirty_log *log, status_type_t status,
char *result, unsigned int maxlen)
{
int sz = 0;
char buffer[16];
struct log_c *lc = log->context;
switch(status) {
case STATUSTYPE_INFO:
break;
case STATUSTYPE_TABLE:
format_dev_t(buffer, lc->log_dev->bdev->bd_dev);
DMEMIT("%s %u %s %u ", log->type->name,
lc->sync == DEFAULTSYNC ? 2 : 3, buffer,
lc->region_size);
DMEMIT_SYNC;
}
return sz;
}
static struct dirty_log_type _core_type = {
.name = "core",
.module = THIS_MODULE,
.ctr = core_ctr,
.dtr = core_dtr,
.get_region_size = core_get_region_size,
.is_clean = core_is_clean,
.in_sync = core_in_sync,
.flush = core_flush,
.mark_region = core_mark_region,
.clear_region = core_clear_region,
.get_resync_work = core_get_resync_work,
.complete_resync_work = core_complete_resync_work,
.get_sync_count = core_get_sync_count,
.status = core_status,
};
static struct dirty_log_type _disk_type = {
.name = "disk",
.module = THIS_MODULE,
.ctr = disk_ctr,
.dtr = disk_dtr,
.suspend = disk_flush,
.resume = disk_resume,
.get_region_size = core_get_region_size,
.is_clean = core_is_clean,
.in_sync = core_in_sync,
.flush = disk_flush,
.mark_region = core_mark_region,
.clear_region = core_clear_region,
.get_resync_work = core_get_resync_work,
.complete_resync_work = core_complete_resync_work,
.get_sync_count = core_get_sync_count,
.status = disk_status,
};
int __init dm_dirty_log_init(void)
{
int r;
r = dm_register_dirty_log_type(&_core_type);
if (r)
DMWARN("couldn't register core log");
r = dm_register_dirty_log_type(&_disk_type);
if (r) {
DMWARN("couldn't register disk type");
dm_unregister_dirty_log_type(&_core_type);
}
return r;
}
void dm_dirty_log_exit(void)
{
dm_unregister_dirty_log_type(&_disk_type);
dm_unregister_dirty_log_type(&_core_type);
}
EXPORT_SYMBOL(dm_register_dirty_log_type);
EXPORT_SYMBOL(dm_unregister_dirty_log_type);
EXPORT_SYMBOL(dm_create_dirty_log);
EXPORT_SYMBOL(dm_destroy_dirty_log);