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/*
* Copyright (C) 2003 Sistina Software
* Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
*
* This file is released under the LGPL.
*/
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/vmalloc.h>
#include <linux/dm-io.h>
#include <linux/dm-dirty-log.h>
#include <linux/device-mapper.h>
#define DM_MSG_PREFIX "dirty region log"
static LIST_HEAD(_log_types);
static DEFINE_SPINLOCK(_lock);
static struct dm_dirty_log_type *__find_dirty_log_type(const char *name)
{
struct dm_dirty_log_type *log_type;
list_for_each_entry(log_type, &_log_types, list)
if (!strcmp(name, log_type->name))
return log_type;
return NULL;
}
static struct dm_dirty_log_type *_get_dirty_log_type(const char *name)
{
struct dm_dirty_log_type *log_type;
spin_lock(&_lock);
log_type = __find_dirty_log_type(name);
if (log_type && !try_module_get(log_type->module))
log_type = NULL;
spin_unlock(&_lock);
return log_type;
}
/*
* get_type
* @type_name
*
* Attempt to retrieve the dm_dirty_log_type by name. If not already
* available, attempt to load the appropriate module.
*
* Log modules are named "dm-log-" followed by the 'type_name'.
* Modules may contain multiple types.
* This function will first try the module "dm-log-<type_name>",
* then truncate 'type_name' on the last '-' and try again.
*
* For example, if type_name was "clustered-disk", it would search
* 'dm-log-clustered-disk' then 'dm-log-clustered'.
*
* Returns: dirty_log_type* on success, NULL on failure
*/
static struct dm_dirty_log_type *get_type(const char *type_name)
{
char *p, *type_name_dup;
struct dm_dirty_log_type *log_type;
if (!type_name)
return NULL;
log_type = _get_dirty_log_type(type_name);
if (log_type)
return log_type;
type_name_dup = kstrdup(type_name, GFP_KERNEL);
if (!type_name_dup) {
DMWARN("No memory left to attempt log module load for \"%s\"",
type_name);
return NULL;
}
while (request_module("dm-log-%s", type_name_dup) ||
!(log_type = _get_dirty_log_type(type_name))) {
p = strrchr(type_name_dup, '-');
if (!p)
break;
p[0] = '\0';
}
if (!log_type)
DMWARN("Module for logging type \"%s\" not found.", type_name);
kfree(type_name_dup);
return log_type;
}
static void put_type(struct dm_dirty_log_type *type)
{
if (!type)
return;
spin_lock(&_lock);
if (!__find_dirty_log_type(type->name))
goto out;
module_put(type->module);
out:
spin_unlock(&_lock);
}
int dm_dirty_log_type_register(struct dm_dirty_log_type *type)
{
int r = 0;
spin_lock(&_lock);
if (!__find_dirty_log_type(type->name))
list_add(&type->list, &_log_types);
else
r = -EEXIST;
spin_unlock(&_lock);
return r;
}
EXPORT_SYMBOL(dm_dirty_log_type_register);
int dm_dirty_log_type_unregister(struct dm_dirty_log_type *type)
{
spin_lock(&_lock);
if (!__find_dirty_log_type(type->name)) {
spin_unlock(&_lock);
return -EINVAL;
}
list_del(&type->list);
spin_unlock(&_lock);
return 0;
}
EXPORT_SYMBOL(dm_dirty_log_type_unregister);
struct dm_dirty_log *dm_dirty_log_create(const char *type_name,
struct dm_target *ti,
int (*flush_callback_fn)(struct dm_target *ti),
unsigned int argc, char **argv)
{
struct dm_dirty_log_type *type;
struct dm_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->flush_callback_fn = flush_callback_fn;
log->type = type;
if (type->ctr(log, ti, argc, argv)) {
kfree(log);
put_type(type);
return NULL;
}
return log;
}
EXPORT_SYMBOL(dm_dirty_log_create);
void dm_dirty_log_destroy(struct dm_dirty_log *log)
{
log->type->dtr(log);
put_type(log->type);
kfree(log);
}
EXPORT_SYMBOL(dm_dirty_log_destroy);
/*-----------------------------------------------------------------
* 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 2
#define LOG_OFFSET 2
struct log_header_disk {
__le32 magic;
/*
* Simple, incrementing version. no backward
* compatibility.
*/
__le32 version;
__le64 nr_regions;
} __packed;
struct log_header_core {
uint32_t magic;
uint32_t version;
uint64_t nr_regions;
};
struct log_c {
struct dm_target *ti;
int touched_dirtied;
int touched_cleaned;
int flush_failed;
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;
struct dm_io_request io_req;
/*
* Disk log fields
*/
int log_dev_failed;
int log_dev_flush_failed;
struct dm_dev *log_dev;
struct log_header_core header;
struct dm_io_region header_location;
struct log_header_disk *disk_header;
};
/*
* 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_le(bit, bs) ? 1 : 0;
}
static inline void log_set_bit(struct log_c *l,
uint32_t *bs, unsigned bit)
{
__set_bit_le(bit, bs);
l->touched_cleaned = 1;
}
static inline void log_clear_bit(struct log_c *l,
uint32_t *bs, unsigned bit)
{
__clear_bit_le(bit, bs);
l->touched_dirtied = 1;
}
/*----------------------------------------------------------------
* Header IO
*--------------------------------------------------------------*/
static void header_to_disk(struct log_header_core *core, struct log_header_disk *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 *core, struct log_header_disk *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 rw_header(struct log_c *lc, int op)
{
lc->io_req.bi_op = op;
lc->io_req.bi_op_flags = 0;
return dm_io(&lc->io_req, 1, &lc->header_location, NULL);
}
static int flush_header(struct log_c *lc)
{
struct dm_io_region null_location = {
.bdev = lc->header_location.bdev,
.sector = 0,
.count = 0,
};
lc->io_req.bi_op = REQ_OP_WRITE;
lc->io_req.bi_op_flags = REQ_PREFLUSH;
return dm_io(&lc->io_req, 1, &null_location, NULL);
}
static int read_header(struct log_c *log)
{
int r;
r = rw_header(log, REQ_OP_READ);
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;
}
#ifdef __LITTLE_ENDIAN
if (log->header.version == 1)
log->header.version = 2;
#endif
if (log->header.version != MIRROR_DISK_VERSION) {
DMWARN("incompatible disk log version");
return -EINVAL;
}
return 0;
}
static int _check_region_size(struct dm_target *ti, uint32_t region_size)
{
if (region_size < 2 || region_size > ti->len)
return 0;
if (!is_power_of_2(region_size))
return 0;
return 1;
}
/*----------------------------------------------------------------
* core log constructor/destructor
*
* argv contains region_size followed optionally by [no]sync
*--------------------------------------------------------------*/
#define BYTE_SHIFT 3
static int create_log_context(struct dm_dirty_log *log, struct dm_target *ti,
unsigned int argc, char **argv,
struct dm_dev *dev)
{
enum sync sync = DEFAULTSYNC;
struct log_c *lc;
uint32_t region_size;
unsigned int region_count;
size_t bitset_size, buf_size;
int r;
char dummy;
if (argc < 1 || argc > 2) {
DMWARN("wrong number of arguments to dirty region 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 "
"dirty region log: %s", argv[1]);
return -EINVAL;
}
}
if (sscanf(argv[0], "%u%c", &region_size, &dummy) != 1 ||
!_check_region_size(ti, region_size)) {
DMWARN("invalid region size %s", argv[0]);
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_dirtied = 0;
lc->touched_cleaned = 0;
lc->flush_failed = 0;
lc->region_size = region_size;
lc->region_count = region_count;
lc->sync = sync;
/*
* Work out how many "unsigned long"s 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 / sizeof(*lc->clean_bits);
/*
* Disk log?
*/
if (!dev) {
lc->clean_bits = vmalloc(bitset_size);
if (!lc->clean_bits) {
DMWARN("couldn't allocate clean bitset");
kfree(lc);
return -ENOMEM;
}
lc->disk_header = NULL;
} else {
lc->log_dev = dev;
lc->log_dev_failed = 0;
lc->log_dev_flush_failed = 0;
lc->header_location.bdev = lc->log_dev->bdev;
lc->header_location.sector = 0;
/*
* Buffer holds both header and bitset.
*/
buf_size =
dm_round_up((LOG_OFFSET << SECTOR_SHIFT) + bitset_size,
bdev_logical_block_size(lc->header_location.
bdev));
if (buf_size > i_size_read(dev->bdev->bd_inode)) {
DMWARN("log device %s too small: need %llu bytes",
dev->name, (unsigned long long)buf_size);
kfree(lc);
return -EINVAL;
}
lc->header_location.count = buf_size >> SECTOR_SHIFT;
lc->io_req.mem.type = DM_IO_VMA;
lc->io_req.notify.fn = NULL;
lc->io_req.client = dm_io_client_create();
if (IS_ERR(lc->io_req.client)) {
r = PTR_ERR(lc->io_req.client);
DMWARN("couldn't allocate disk io client");
kfree(lc);
return r;
}
lc->disk_header = vmalloc(buf_size);
if (!lc->disk_header) {
DMWARN("couldn't allocate disk log buffer");
dm_io_client_destroy(lc->io_req.client);
kfree(lc);
return -ENOMEM;
}
lc->io_req.mem.ptr.vma = lc->disk_header;
lc->clean_bits = (void *)lc->disk_header +
(LOG_OFFSET << SECTOR_SHIFT);
}
memset(lc->clean_bits, -1, bitset_size);
lc->sync_bits = vmalloc(bitset_size);
if (!lc->sync_bits) {
DMWARN("couldn't allocate sync bitset");
if (!dev)
vfree(lc->clean_bits);
else
dm_io_client_destroy(lc->io_req.client);
vfree(lc->disk_header);
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 = vzalloc(bitset_size);
if (!lc->recovering_bits) {
DMWARN("couldn't allocate sync bitset");
vfree(lc->sync_bits);
if (!dev)
vfree(lc->clean_bits);
else
dm_io_client_destroy(lc->io_req.client);
vfree(lc->disk_header);
kfree(lc);
return -ENOMEM;
}
lc->sync_search = 0;
log->context = lc;
return 0;
}
static int core_ctr(struct dm_dirty_log *log, struct dm_target *ti,
unsigned int argc, char **argv)
{
return create_log_context(log, ti, argc, argv, NULL);
}
static void destroy_log_context(struct log_c *lc)
{
vfree(lc->sync_bits);
vfree(lc->recovering_bits);
kfree(lc);
}
static void core_dtr(struct dm_dirty_log *log)
{
struct log_c *lc = (struct log_c *) log->context;
vfree(lc->clean_bits);
destroy_log_context(lc);
}
/*----------------------------------------------------------------
* disk log constructor/destructor
*
* argv contains log_device region_size followed optionally by [no]sync
*--------------------------------------------------------------*/
static int disk_ctr(struct dm_dirty_log *log, struct dm_target *ti,
unsigned int argc, char **argv)
{
int r;
struct dm_dev *dev;
if (argc < 2 || argc > 3) {
DMWARN("wrong number of arguments to disk dirty region log");
return -EINVAL;
}
r = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &dev);
if (r)
return r;
r = create_log_context(log, ti, argc - 1, argv + 1, dev);
if (r) {
dm_put_device(ti, dev);
return r;
}
return 0;
}
static void disk_dtr(struct dm_dirty_log *log)
{
struct log_c *lc = (struct log_c *) log->context;
dm_put_device(lc->ti, lc->log_dev);
vfree(lc->disk_header);
dm_io_client_destroy(lc->io_req.client);
destroy_log_context(lc);
}
static void fail_log_device(struct log_c *lc)
{
if (lc->log_dev_failed)
return;
lc->log_dev_failed = 1;
dm_table_event(lc->ti->table);
}
static int disk_resume(struct dm_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) {
DMWARN("%s: Failed to read header on dirty region log device",
lc->log_dev->name);
fail_log_device(lc);
/*
* If the log device cannot be read, we must assume
* all regions are out-of-sync. If we simply return
* here, the state will be uninitialized and could
* lead us to return 'in-sync' status for regions
* that are actually 'out-of-sync'.
*/
lc->header.nr_regions = 0;
}
/* set or clear any new bits -- device has grown */
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);
/* clear any old bits -- device has shrunk */
for (i = lc->region_count; i % (sizeof(*lc->clean_bits) << BYTE_SHIFT); i++)
log_clear_bit(lc, lc->clean_bits, i);
/* copy clean across to sync */
memcpy(lc->sync_bits, lc->clean_bits, size);
lc->sync_count = memweight(lc->clean_bits,
lc->bitset_uint32_count * sizeof(uint32_t));
lc->sync_search = 0;
/* set the correct number of regions in the header */
lc->header.nr_regions = lc->region_count;
header_to_disk(&lc->header, lc->disk_header);
/* write the new header */
r = rw_header(lc, REQ_OP_WRITE);
if (!r) {
r = flush_header(lc);
if (r)
lc->log_dev_flush_failed = 1;
}
if (r) {
DMWARN("%s: Failed to write header on dirty region log device",
lc->log_dev->name);
fail_log_device(lc);
}
return r;
}
static uint32_t core_get_region_size(struct dm_dirty_log *log)
{
struct log_c *lc = (struct log_c *) log->context;
return lc->region_size;
}
static int core_resume(struct dm_dirty_log *log)
{
struct log_c *lc = (struct log_c *) log->context;
lc->sync_search = 0;
return 0;
}
static int core_is_clean(struct dm_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 dm_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 dm_dirty_log *log)
{
/* no op */
return 0;
}
static int disk_flush(struct dm_dirty_log *log)
{
int r, i;
struct log_c *lc = log->context;
/* only write if the log has changed */
if (!lc->touched_cleaned && !lc->touched_dirtied)
return 0;
if (lc->touched_cleaned && log->flush_callback_fn &&
log->flush_callback_fn(lc->ti)) {
/*
* At this point it is impossible to determine which
* regions are clean and which are dirty (without
* re-reading the log off disk). So mark all of them
* dirty.
*/
lc->flush_failed = 1;
for (i = 0; i < lc->region_count; i++)
log_clear_bit(lc, lc->clean_bits, i);
}
r = rw_header(lc, REQ_OP_WRITE);
if (r)
fail_log_device(lc);
else {
if (lc->touched_dirtied) {
r = flush_header(lc);
if (r) {
lc->log_dev_flush_failed = 1;
fail_log_device(lc);
} else
lc->touched_dirtied = 0;
}
lc->touched_cleaned = 0;
}
return r;
}
static void core_mark_region(struct dm_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 dm_dirty_log *log, region_t region)
{
struct log_c *lc = (struct log_c *) log->context;
if (likely(!lc->flush_failed))
log_set_bit(lc, lc->clean_bits, region);
}
static int core_get_resync_work(struct dm_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_le(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_set_region_sync(struct dm_dirty_log *log, region_t region,
int in_sync)
{
struct log_c *lc = (struct log_c *) log->context;
log_clear_bit(lc, lc->recovering_bits, region);
if (in_sync) {
log_set_bit(lc, lc->sync_bits, region);
lc->sync_count++;
} else if (log_test_bit(lc->sync_bits, region)) {
lc->sync_count--;
log_clear_bit(lc, lc->sync_bits, region);
}
}
static region_t core_get_sync_count(struct dm_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 dm_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:
DMEMIT("1 %s", log->type->name);
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 dm_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:
DMEMIT("3 %s %s %c", log->type->name, lc->log_dev->name,
lc->log_dev_flush_failed ? 'F' :
lc->log_dev_failed ? 'D' :
'A');
break;
case STATUSTYPE_TABLE:
DMEMIT("%s %u %s %u ", log->type->name,
lc->sync == DEFAULTSYNC ? 2 : 3, lc->log_dev->name,
lc->region_size);
DMEMIT_SYNC;
}
return sz;
}
static struct dm_dirty_log_type _core_type = {
.name = "core",
.module = THIS_MODULE,
.ctr = core_ctr,
.dtr = core_dtr,
.resume = core_resume,
.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,
.set_region_sync = core_set_region_sync,
.get_sync_count = core_get_sync_count,
.status = core_status,
};
static struct dm_dirty_log_type _disk_type = {
.name = "disk",
.module = THIS_MODULE,
.ctr = disk_ctr,
.dtr = disk_dtr,
.postsuspend = 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,
.set_region_sync = core_set_region_sync,
.get_sync_count = core_get_sync_count,
.status = disk_status,
};
static int __init dm_dirty_log_init(void)
{
int r;
r = dm_dirty_log_type_register(&_core_type);
if (r)
DMWARN("couldn't register core log");
r = dm_dirty_log_type_register(&_disk_type);
if (r) {
DMWARN("couldn't register disk type");
dm_dirty_log_type_unregister(&_core_type);
}
return r;
}
static void __exit dm_dirty_log_exit(void)
{
dm_dirty_log_type_unregister(&_disk_type);
dm_dirty_log_type_unregister(&_core_type);
}
module_init(dm_dirty_log_init);
module_exit(dm_dirty_log_exit);
MODULE_DESCRIPTION(DM_NAME " dirty region log");
MODULE_AUTHOR("Joe Thornber, Heinz Mauelshagen <dm-devel@redhat.com>");
MODULE_LICENSE("GPL");