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>
diff --git a/drivers/md/dm-exception-store.c b/drivers/md/dm-exception-store.c
index 2078b92..a2e26c2 100644
--- a/drivers/md/dm-exception-store.c
+++ b/drivers/md/dm-exception-store.c
@@ -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 @@
}
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);
}
diff --git a/drivers/md/dm-exception-store.h b/drivers/md/dm-exception-store.h
index 835f402..023a707 100644
--- a/drivers/md/dm-exception-store.h
+++ b/drivers/md/dm-exception-store.h
@@ -167,9 +167,8 @@
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_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);
diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c
index fcb1ac1..974916b 100644
--- a/drivers/md/dm-snap.c
+++ b/drivers/md/dm-snap.c
@@ -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 @@
/*
* 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 @@
* 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);
@@ -576,60 +574,6 @@
}
/*
- * 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>
*/
static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
@@ -637,55 +581,45 @@
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 @@
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 @@
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 @@
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 @@
int i;
#endif
struct dm_snapshot *s = ti->private;
- struct dm_dev *cow = s->store->cow;
flush_workqueue(ksnapd);
@@ -831,7 +753,8 @@
mempool_destroy(s->pending_pool);
dm_put_device(ti, s->origin);
- dm_put_device(ti, cow);
+
+ dm_exception_store_destroy(s->store);
kfree(s);
}