dm snapshot: move ctr parsing to exception store (fee1998e) · Commits · jan.koester / Linux

drivers/md/dm-exception-store.c

+95 −14

Original line number	Diff line number	Diff line
		@@ -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);
		}

drivers/md/dm-exception-store.h

+2 −3

Original line number	Diff line number	Diff line
		@@ -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);

drivers/md/dm-snap.c

+35 −112

Original line number	Diff line number	Diff line
		@@ -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,
		@@ -765,24 +691,23 @@ static int snapshot_ctr(struct dm_target ti, unsigned int argc, char *argv)
		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);
		}