dm exception store: move chunk_fields

Move chunk fields from snapshot to exception store.

Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
This commit is contained in:
Jonathan Brassow 2009-04-02 19:55:32 +01:00 committed by Alasdair G Kergon
parent 0cea9c7827
commit d021684951
6 changed files with 67 additions and 53 deletions

View file

@ -138,6 +138,8 @@ int dm_exception_store_type_unregister(struct dm_exception_store_type *type)
EXPORT_SYMBOL(dm_exception_store_type_unregister);
int dm_exception_store_create(const char *type_name, struct dm_target *ti,
chunk_t chunk_size, chunk_t chunk_mask,
chunk_t chunk_shift,
struct dm_exception_store **store)
{
int r = 0;
@ -157,6 +159,10 @@ int dm_exception_store_create(const char *type_name, struct dm_target *ti,
tmp_store->type = type;
tmp_store->ti = ti;
tmp_store->chunk_size = chunk_size;
tmp_store->chunk_mask = chunk_mask;
tmp_store->chunk_shift = chunk_shift;
r = type->ctr(tmp_store, 0, NULL);
if (r) {
put_type(type);

View file

@ -99,6 +99,11 @@ struct dm_exception_store {
struct dm_snapshot *snap;
/* Size of data blocks saved - must be a power of 2 */
chunk_t chunk_size;
chunk_t chunk_mask;
chunk_t chunk_shift;
void *context;
};
@ -149,6 +154,8 @@ int dm_exception_store_type_register(struct dm_exception_store_type *type);
int dm_exception_store_type_unregister(struct dm_exception_store_type *type);
int dm_exception_store_create(const char *type_name, struct dm_target *ti,
chunk_t chunk_size, chunk_t chunk_mask,
chunk_t chunk_shift,
struct dm_exception_store **store);
void dm_exception_store_destroy(struct dm_exception_store *store);

View file

@ -141,7 +141,7 @@ static int alloc_area(struct pstore *ps)
int r = -ENOMEM;
size_t len;
len = ps->snap->chunk_size << SECTOR_SHIFT;
len = ps->snap->store->chunk_size << SECTOR_SHIFT;
/*
* Allocate the chunk_size block of memory that will hold
@ -190,8 +190,8 @@ static int chunk_io(struct pstore *ps, chunk_t chunk, int rw, int metadata)
{
struct dm_io_region where = {
.bdev = ps->snap->cow->bdev,
.sector = ps->snap->chunk_size * chunk,
.count = ps->snap->chunk_size,
.sector = ps->snap->store->chunk_size * chunk,
.count = ps->snap->store->chunk_size,
};
struct dm_io_request io_req = {
.bi_rw = rw,
@ -247,15 +247,15 @@ static int area_io(struct pstore *ps, int rw)
static void zero_memory_area(struct pstore *ps)
{
memset(ps->area, 0, ps->snap->chunk_size << SECTOR_SHIFT);
memset(ps->area, 0, ps->snap->store->chunk_size << SECTOR_SHIFT);
}
static int zero_disk_area(struct pstore *ps, chunk_t area)
{
struct dm_io_region where = {
.bdev = ps->snap->cow->bdev,
.sector = ps->snap->chunk_size * area_location(ps, area),
.count = ps->snap->chunk_size,
.sector = ps->snap->store->chunk_size * area_location(ps, area),
.count = ps->snap->store->chunk_size,
};
struct dm_io_request io_req = {
.bi_rw = WRITE,
@ -278,16 +278,17 @@ static int read_header(struct pstore *ps, int *new_snapshot)
/*
* Use default chunk size (or hardsect_size, if larger) if none supplied
*/
if (!ps->snap->chunk_size) {
ps->snap->chunk_size = max(DM_CHUNK_SIZE_DEFAULT_SECTORS,
if (!ps->snap->store->chunk_size) {
ps->snap->store->chunk_size = max(DM_CHUNK_SIZE_DEFAULT_SECTORS,
bdev_hardsect_size(ps->snap->cow->bdev) >> 9);
ps->snap->chunk_mask = ps->snap->chunk_size - 1;
ps->snap->chunk_shift = ffs(ps->snap->chunk_size) - 1;
ps->snap->store->chunk_mask = ps->snap->store->chunk_size - 1;
ps->snap->store->chunk_shift = ffs(ps->snap->store->chunk_size)
- 1;
chunk_size_supplied = 0;
}
ps->io_client = dm_io_client_create(sectors_to_pages(ps->snap->
chunk_size));
store->chunk_size));
if (IS_ERR(ps->io_client))
return PTR_ERR(ps->io_client);
@ -317,22 +318,22 @@ static int read_header(struct pstore *ps, int *new_snapshot)
ps->version = le32_to_cpu(dh->version);
chunk_size = le32_to_cpu(dh->chunk_size);
if (!chunk_size_supplied || ps->snap->chunk_size == chunk_size)
if (!chunk_size_supplied || ps->snap->store->chunk_size == chunk_size)
return 0;
DMWARN("chunk size %llu in device metadata overrides "
"table chunk size of %llu.",
(unsigned long long)chunk_size,
(unsigned long long)ps->snap->chunk_size);
(unsigned long long)ps->snap->store->chunk_size);
/* We had a bogus chunk_size. Fix stuff up. */
free_area(ps);
ps->snap->chunk_size = chunk_size;
ps->snap->chunk_mask = chunk_size - 1;
ps->snap->chunk_shift = ffs(chunk_size) - 1;
ps->snap->store->chunk_size = chunk_size;
ps->snap->store->chunk_mask = chunk_size - 1;
ps->snap->store->chunk_shift = ffs(chunk_size) - 1;
r = dm_io_client_resize(sectors_to_pages(ps->snap->chunk_size),
r = dm_io_client_resize(sectors_to_pages(ps->snap->store->chunk_size),
ps->io_client);
if (r)
return r;
@ -349,13 +350,13 @@ static int write_header(struct pstore *ps)
{
struct disk_header *dh;
memset(ps->area, 0, ps->snap->chunk_size << SECTOR_SHIFT);
memset(ps->area, 0, ps->snap->store->chunk_size << SECTOR_SHIFT);
dh = (struct disk_header *) ps->area;
dh->magic = cpu_to_le32(SNAP_MAGIC);
dh->valid = cpu_to_le32(ps->valid);
dh->version = cpu_to_le32(ps->version);
dh->chunk_size = cpu_to_le32(ps->snap->chunk_size);
dh->chunk_size = cpu_to_le32(ps->snap->store->chunk_size);
return chunk_io(ps, 0, WRITE, 1);
}
@ -474,7 +475,7 @@ static struct pstore *get_info(struct dm_exception_store *store)
static void persistent_fraction_full(struct dm_exception_store *store,
sector_t *numerator, sector_t *denominator)
{
*numerator = get_info(store)->next_free * store->snap->chunk_size;
*numerator = get_info(store)->next_free * store->chunk_size;
*denominator = get_dev_size(store->snap->cow->bdev);
}
@ -507,8 +508,8 @@ static int persistent_read_metadata(struct dm_exception_store *store,
/*
* Now we know correct chunk_size, complete the initialisation.
*/
ps->exceptions_per_area = (ps->snap->chunk_size << SECTOR_SHIFT) /
sizeof(struct disk_exception);
ps->exceptions_per_area = (ps->snap->store->chunk_size << SECTOR_SHIFT)
/ sizeof(struct disk_exception);
ps->callbacks = dm_vcalloc(ps->exceptions_per_area,
sizeof(*ps->callbacks));
if (!ps->callbacks)
@ -567,7 +568,7 @@ static int persistent_prepare_exception(struct dm_exception_store *store,
sector_t size = get_dev_size(store->snap->cow->bdev);
/* Is there enough room ? */
if (size < ((ps->next_free + 1) * store->snap->chunk_size))
if (size < ((ps->next_free + 1) * store->chunk_size))
return -ENOSPC;
e->new_chunk = ps->next_free;

View file

@ -42,11 +42,11 @@ static int transient_prepare_exception(struct dm_exception_store *store,
struct transient_c *tc = store->context;
sector_t size = get_dev_size(store->snap->cow->bdev);
if (size < (tc->next_free + store->snap->chunk_size))
if (size < (tc->next_free + store->chunk_size))
return -1;
e->new_chunk = sector_to_chunk(store->snap, tc->next_free);
tc->next_free += store->snap->chunk_size;
tc->next_free += store->chunk_size;
return 0;
}

View file

@ -468,7 +468,7 @@ static int calc_max_buckets(void)
/*
* Allocate room for a suitable hash table.
*/
static int init_hash_tables(struct dm_snapshot *s)
static int init_hash_tables(struct dm_snapshot *s, chunk_t chunk_shift)
{
sector_t hash_size, cow_dev_size, origin_dev_size, max_buckets;
@ -480,7 +480,7 @@ static int init_hash_tables(struct dm_snapshot *s)
origin_dev_size = get_dev_size(s->origin->bdev);
max_buckets = calc_max_buckets();
hash_size = min(origin_dev_size, cow_dev_size) >> s->chunk_shift;
hash_size = min(origin_dev_size, cow_dev_size) >> chunk_shift;
hash_size = min(hash_size, max_buckets);
hash_size = rounddown_pow_of_two(hash_size);
@ -515,19 +515,20 @@ static ulong round_up(ulong n, ulong size)
}
static int set_chunk_size(struct dm_snapshot *s, const char *chunk_size_arg,
char **error)
chunk_t *chunk_size, chunk_t *chunk_mask,
chunk_t *chunk_shift, char **error)
{
unsigned long chunk_size;
unsigned long chunk_size_ulong;
char *value;
chunk_size = simple_strtoul(chunk_size_arg, &value, 10);
chunk_size_ulong = simple_strtoul(chunk_size_arg, &value, 10);
if (*chunk_size_arg == '\0' || *value != '\0') {
*error = "Invalid chunk size";
return -EINVAL;
}
if (!chunk_size) {
s->chunk_size = s->chunk_mask = s->chunk_shift = 0;
if (!chunk_size_ulong) {
*chunk_size = *chunk_mask = *chunk_shift = 0;
return 0;
}
@ -535,23 +536,23 @@ static int set_chunk_size(struct dm_snapshot *s, const char *chunk_size_arg,
* Chunk size must be multiple of page size. Silently
* round up if it's not.
*/
chunk_size = round_up(chunk_size, PAGE_SIZE >> 9);
chunk_size_ulong = round_up(chunk_size_ulong, PAGE_SIZE >> 9);
/* Check chunk_size is a power of 2 */
if (!is_power_of_2(chunk_size)) {
if (!is_power_of_2(chunk_size_ulong)) {
*error = "Chunk size is not a power of 2";
return -EINVAL;
}
/* Validate the chunk size against the device block size */
if (chunk_size % (bdev_hardsect_size(s->cow->bdev) >> 9)) {
if (chunk_size_ulong % (bdev_hardsect_size(s->cow->bdev) >> 9)) {
*error = "Chunk size is not a multiple of device blocksize";
return -EINVAL;
}
s->chunk_size = chunk_size;
s->chunk_mask = chunk_size - 1;
s->chunk_shift = ffs(chunk_size) - 1;
*chunk_size = chunk_size_ulong;
*chunk_mask = chunk_size_ulong - 1;
*chunk_shift = ffs(chunk_size_ulong) - 1;
return 0;
}
@ -567,6 +568,7 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
char persistent;
char *origin_path;
char *cow_path;
chunk_t chunk_size, chunk_mask, chunk_shift;
if (argc != 4) {
ti->error = "requires exactly 4 arguments";
@ -606,7 +608,8 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
goto bad2;
}
r = set_chunk_size(s, argv[3], &ti->error);
r = set_chunk_size(s, argv[3], &chunk_size, &chunk_mask, &chunk_shift,
&ti->error);
if (r)
goto bad3;
@ -617,13 +620,14 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
spin_lock_init(&s->pe_lock);
/* Allocate hash table for COW data */
if (init_hash_tables(s)) {
if (init_hash_tables(s, chunk_shift)) {
ti->error = "Unable to allocate hash table space";
r = -ENOMEM;
goto bad3;
}
r = dm_exception_store_create(argv[2], ti, &s->store);
r = dm_exception_store_create(argv[2], ti, chunk_size, chunk_mask,
chunk_shift, &s->store);
if (r) {
ti->error = "Couldn't create exception store";
r = -EINVAL;
@ -680,7 +684,7 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
}
ti->private = s;
ti->split_io = s->chunk_size;
ti->split_io = s->store->chunk_size;
return 0;
@ -955,7 +959,7 @@ static void start_copy(struct dm_snap_pending_exception *pe)
src.bdev = bdev;
src.sector = chunk_to_sector(s, pe->e.old_chunk);
src.count = min(s->chunk_size, dev_size - src.sector);
src.count = min(s->store->chunk_size, dev_size - src.sector);
dest.bdev = s->cow->bdev;
dest.sector = chunk_to_sector(s, pe->e.new_chunk);
@ -1021,7 +1025,7 @@ static void remap_exception(struct dm_snapshot *s, struct dm_snap_exception *e,
bio->bi_bdev = s->cow->bdev;
bio->bi_sector = chunk_to_sector(s, dm_chunk_number(e->new_chunk) +
(chunk - e->old_chunk)) +
(bio->bi_sector & s->chunk_mask);
(bio->bi_sector & s->store->chunk_mask);
}
static int snapshot_map(struct dm_target *ti, struct bio *bio,
@ -1166,7 +1170,7 @@ static int snapshot_status(struct dm_target *ti, status_type_t type,
snprintf(result, maxlen, "%s %s %s %llu",
snap->origin->name, snap->cow->name,
snap->store->type->name,
(unsigned long long)snap->chunk_size);
(unsigned long long)snap->store->chunk_size);
break;
}
@ -1377,7 +1381,8 @@ static void origin_resume(struct dm_target *ti)
o = __lookup_origin(dev->bdev);
if (o)
list_for_each_entry (snap, &o->snapshots, list)
chunk_size = min_not_zero(chunk_size, snap->chunk_size);
chunk_size = min_not_zero(chunk_size,
snap->store->chunk_size);
up_read(&_origins_lock);
ti->split_io = chunk_size;

View file

@ -32,11 +32,6 @@ struct dm_snapshot {
/* List of snapshots per Origin */
struct list_head list;
/* Size of data blocks saved - must be a power of 2 */
chunk_t chunk_size;
chunk_t chunk_mask;
chunk_t chunk_shift;
/* You can't use a snapshot if this is 0 (e.g. if full) */
int valid;
@ -84,12 +79,12 @@ static inline sector_t get_dev_size(struct block_device *bdev)
static inline chunk_t sector_to_chunk(struct dm_snapshot *s, sector_t sector)
{
return (sector & ~s->chunk_mask) >> s->chunk_shift;
return (sector & ~s->store->chunk_mask) >> s->store->chunk_shift;
}
static inline sector_t chunk_to_sector(struct dm_snapshot *s, chunk_t chunk)
{
return chunk << s->chunk_shift;
return chunk << s->store->chunk_shift;
}
static inline int bdev_equal(struct block_device *lhs, struct block_device *rhs)