dm snapshot: move ctr parsing to exception store

First step of having the exception stores parse their own arguments -
generalizing the interface.

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 19:55:34 +01:00 committed by Alasdair G Kergon
parent 2e4a31df2b
commit fee1998e9c
3 changed files with 132 additions and 129 deletions

View file

@ -7,6 +7,7 @@
#include "dm-exception-store.h"
#include <linux/ctype.h>
#include <linux/mm.h>
#include <linux/pagemap.h>
#include <linux/vmalloc.h>
@ -137,49 +138,129 @@ 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_dev *cow,
/*
* Round a number up to the nearest 'size' boundary. size must
* be a power of 2.
*/
static ulong round_up(ulong n, ulong size)
{
size--;
return (n + size) & ~size;
}
static int set_chunk_size(struct dm_exception_store *store,
const char *chunk_size_arg, char **error)
{
unsigned long chunk_size_ulong;
char *value;
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_ulong) {
store->chunk_size = store->chunk_mask = store->chunk_shift = 0;
return 0;
}
/*
* Chunk size must be multiple of page size. Silently
* round up if it's not.
*/
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_ulong)) {
*error = "Chunk size is not a power of 2";
return -EINVAL;
}
/* Validate the chunk size against the device block size */
if (chunk_size_ulong % (bdev_hardsect_size(store->cow->bdev) >> 9)) {
*error = "Chunk size is not a multiple of device blocksize";
return -EINVAL;
}
store->chunk_size = chunk_size_ulong;
store->chunk_mask = chunk_size_ulong - 1;
store->chunk_shift = ffs(chunk_size_ulong) - 1;
return 0;
}
int dm_exception_store_create(struct dm_target *ti, int argc, char **argv,
unsigned *args_used,
struct dm_exception_store **store)
{
int r = 0;
struct dm_exception_store_type *type;
struct dm_exception_store *tmp_store;
char persistent;
if (argc < 3) {
ti->error = "Insufficient exception store arguments";
return -EINVAL;
}
tmp_store = kmalloc(sizeof(*tmp_store), GFP_KERNEL);
if (!tmp_store)
if (!tmp_store) {
ti->error = "Exception store allocation failed";
return -ENOMEM;
}
type = get_type(type_name);
if (!type) {
kfree(tmp_store);
persistent = toupper(*argv[1]);
if (persistent != 'P' && persistent != 'N') {
ti->error = "Persistent flag is not P or N";
return -EINVAL;
}
type = get_type(argv[1]);
if (!type) {
ti->error = "Exception store type not recognised";
r = -EINVAL;
goto bad_type;
}
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 = dm_get_device(ti, argv[0], 0, 0,
FMODE_READ | FMODE_WRITE, &tmp_store->cow);
if (r) {
ti->error = "Cannot get COW device";
goto bad_cow;
}
tmp_store->cow = cow;
r = set_chunk_size(tmp_store, argv[2], &ti->error);
if (r)
goto bad_cow;
r = type->ctr(tmp_store, 0, NULL);
if (r) {
put_type(type);
kfree(tmp_store);
return r;
ti->error = "Exception store type constructor failed";
goto bad_ctr;
}
*args_used = 3;
*store = tmp_store;
return 0;
bad_ctr:
dm_put_device(ti, tmp_store->cow);
bad_cow:
put_type(type);
bad_type:
kfree(tmp_store);
return r;
}
EXPORT_SYMBOL(dm_exception_store_create);
void dm_exception_store_destroy(struct dm_exception_store *store)
{
store->type->dtr(store);
dm_put_device(store->ti, store->cow);
put_type(store->type);
kfree(store);
}

View file

@ -167,9 +167,8 @@ static inline chunk_t sector_to_chunk(struct dm_exception_store *store,
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_dev *cow,
int dm_exception_store_create(struct dm_target *ti, int argc, char **argv,
unsigned *args_used,
struct dm_exception_store **store);
void dm_exception_store_destroy(struct dm_exception_store *store);

View file

@ -7,7 +7,6 @@
*/
#include <linux/blkdev.h>
#include <linux/ctype.h>
#include <linux/device-mapper.h>
#include <linux/delay.h>
#include <linux/fs.h>
@ -538,8 +537,7 @@ static int calc_max_buckets(void)
/*
* Allocate room for a suitable hash table.
*/
static int init_hash_tables(struct dm_snapshot *s, chunk_t chunk_shift,
struct dm_dev *cow)
static int init_hash_tables(struct dm_snapshot *s)
{
sector_t hash_size, cow_dev_size, origin_dev_size, max_buckets;
@ -547,11 +545,11 @@ static int init_hash_tables(struct dm_snapshot *s, chunk_t chunk_shift,
* Calculate based on the size of the original volume or
* the COW volume...
*/
cow_dev_size = get_dev_size(cow->bdev);
cow_dev_size = get_dev_size(s->store->cow->bdev);
origin_dev_size = get_dev_size(s->origin->bdev);
max_buckets = calc_max_buckets();
hash_size = min(origin_dev_size, cow_dev_size) >> chunk_shift;
hash_size = min(origin_dev_size, cow_dev_size) >> s->store->chunk_shift;
hash_size = min(hash_size, max_buckets);
hash_size = rounddown_pow_of_two(hash_size);
@ -575,60 +573,6 @@ static int init_hash_tables(struct dm_snapshot *s, chunk_t chunk_shift,
return 0;
}
/*
* Round a number up to the nearest 'size' boundary. size must
* be a power of 2.
*/
static ulong round_up(ulong n, ulong size)
{
size--;
return (n + size) & ~size;
}
static int set_chunk_size(struct dm_snapshot *s, const char *chunk_size_arg,
chunk_t *chunk_size, chunk_t *chunk_mask,
chunk_t *chunk_shift, struct dm_dev *cow,
char **error)
{
unsigned long chunk_size_ulong;
char *value;
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_ulong) {
*chunk_size = *chunk_mask = *chunk_shift = 0;
return 0;
}
/*
* Chunk size must be multiple of page size. Silently
* round up if it's not.
*/
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_ulong)) {
*error = "Chunk size is not a power of 2";
return -EINVAL;
}
/* Validate the chunk size against the device block size */
if (chunk_size_ulong % (bdev_hardsect_size(cow->bdev) >> 9)) {
*error = "Chunk size is not a multiple of device blocksize";
return -EINVAL;
}
*chunk_size = chunk_size_ulong;
*chunk_mask = chunk_size_ulong - 1;
*chunk_shift = ffs(chunk_size_ulong) - 1;
return 0;
}
/*
* Construct a snapshot mapping: <origin_dev> <COW-dev> <p/n> <chunk-size>
*/
@ -637,55 +581,45 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
struct dm_snapshot *s;
int i;
int r = -EINVAL;
char persistent;
char *origin_path;
char *cow_path;
chunk_t chunk_size, chunk_mask, chunk_shift;
struct dm_dev *cow;
struct dm_exception_store *store;
unsigned args_used;
if (argc != 4) {
ti->error = "requires exactly 4 arguments";
r = -EINVAL;
goto bad1;
goto bad_args;
}
origin_path = argv[0];
cow_path = argv[1];
persistent = toupper(*argv[2]);
argv++;
argc--;
if (persistent != 'P' && persistent != 'N') {
ti->error = "Persistent flag is not P or N";
r = dm_exception_store_create(ti, argc, argv, &args_used, &store);
if (r) {
ti->error = "Couldn't create exception store";
r = -EINVAL;
goto bad1;
goto bad_args;
}
argv += args_used;
argc -= args_used;
s = kmalloc(sizeof(*s), GFP_KERNEL);
if (s == NULL) {
if (!s) {
ti->error = "Cannot allocate snapshot context private "
"structure";
r = -ENOMEM;
goto bad1;
goto bad_snap;
}
r = dm_get_device(ti, origin_path, 0, ti->len, FMODE_READ, &s->origin);
if (r) {
ti->error = "Cannot get origin device";
goto bad2;
goto bad_origin;
}
r = dm_get_device(ti, cow_path, 0, 0,
FMODE_READ | FMODE_WRITE, &cow);
if (r) {
dm_put_device(ti, s->origin);
ti->error = "Cannot get COW device";
goto bad2;
}
r = set_chunk_size(s, argv[3], &chunk_size, &chunk_mask, &chunk_shift,
cow, &ti->error);
if (r)
goto bad3;
s->store = store;
s->valid = 1;
s->active = 0;
atomic_set(&s->pending_exceptions_count, 0);
@ -693,30 +627,22 @@ 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, chunk_shift, cow)) {
if (init_hash_tables(s)) {
ti->error = "Unable to allocate hash table space";
r = -ENOMEM;
goto bad3;
}
r = dm_exception_store_create(argv[2], ti, chunk_size, chunk_mask,
chunk_shift, cow, &s->store);
if (r) {
ti->error = "Couldn't create exception store";
r = -EINVAL;
goto bad4;
goto bad_hash_tables;
}
r = dm_kcopyd_client_create(SNAPSHOT_PAGES, &s->kcopyd_client);
if (r) {
ti->error = "Could not create kcopyd client";
goto bad5;
goto bad_kcopyd;
}
s->pending_pool = mempool_create_slab_pool(MIN_IOS, pending_cache);
if (!s->pending_pool) {
ti->error = "Could not allocate mempool for pending exceptions";
goto bad6;
goto bad_pending_pool;
}
s->tracked_chunk_pool = mempool_create_slab_pool(MIN_IOS,
@ -759,30 +685,29 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
return 0;
bad_load_and_register:
bad_load_and_register:
mempool_destroy(s->tracked_chunk_pool);
bad_tracked_chunk_pool:
bad_tracked_chunk_pool:
mempool_destroy(s->pending_pool);
bad6:
bad_pending_pool:
dm_kcopyd_client_destroy(s->kcopyd_client);
bad5:
s->store->type->dtr(s->store);
bad4:
bad_kcopyd:
exit_exception_table(&s->pending, pending_cache);
exit_exception_table(&s->complete, exception_cache);
bad3:
dm_put_device(ti, cow);
bad_hash_tables:
dm_put_device(ti, s->origin);
bad2:
bad_origin:
kfree(s);
bad1:
bad_snap:
dm_exception_store_destroy(store);
bad_args:
return r;
}
@ -793,8 +718,6 @@ static void __free_exceptions(struct dm_snapshot *s)
exit_exception_table(&s->pending, pending_cache);
exit_exception_table(&s->complete, exception_cache);
s->store->type->dtr(s->store);
}
static void snapshot_dtr(struct dm_target *ti)
@ -803,7 +726,6 @@ static void snapshot_dtr(struct dm_target *ti)
int i;
#endif
struct dm_snapshot *s = ti->private;
struct dm_dev *cow = s->store->cow;
flush_workqueue(ksnapd);
@ -831,7 +753,8 @@ static void snapshot_dtr(struct dm_target *ti)
mempool_destroy(s->pending_pool);
dm_put_device(ti, s->origin);
dm_put_device(ti, cow);
dm_exception_store_destroy(s->store);
kfree(s);
}