dm exception store: introduce registry
Move exception stores into a registry. Signed-off-by: Jonathan Brassow <jbrassow@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
This commit is contained in:
Jonathan Brassow
Alasdair G Kergon
parent
7513c2a761
commit
493df71c64
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@ -14,6 +14,168 @@
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#define DM_MSG_PREFIX "snapshot exception stores"
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static LIST_HEAD(_exception_store_types);
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static DEFINE_SPINLOCK(_lock);
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static struct dm_exception_store_type *__find_exception_store_type(const char *name)
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{
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struct dm_exception_store_type *type;
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list_for_each_entry(type, &_exception_store_types, list)
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if (!strcmp(name, type->name))
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return type;
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return NULL;
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}
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static struct dm_exception_store_type *_get_exception_store_type(const char *name)
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{
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struct dm_exception_store_type *type;
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spin_lock(&_lock);
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type = __find_exception_store_type(name);
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if (type && !try_module_get(type->module))
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type = NULL;
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spin_unlock(&_lock);
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return type;
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}
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/*
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* get_type
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* @type_name
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*
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* Attempt to retrieve the dm_exception_store_type by name. If not already
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* available, attempt to load the appropriate module.
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*
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* Exstore modules are named "dm-exstore-" followed by the 'type_name'.
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* Modules may contain multiple types.
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* This function will first try the module "dm-exstore-<type_name>",
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* then truncate 'type_name' on the last '-' and try again.
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*
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* For example, if type_name was "clustered-shared", it would search
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* 'dm-exstore-clustered-shared' then 'dm-exstore-clustered'.
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*
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* 'dm-exception-store-<type_name>' is too long of a name in my
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* opinion, which is why I've chosen to have the files
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* containing exception store implementations be 'dm-exstore-<type_name>'.
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* If you want your module to be autoloaded, you will follow this
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* naming convention.
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*
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* Returns: dm_exception_store_type* on success, NULL on failure
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*/
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static struct dm_exception_store_type *get_type(const char *type_name)
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{
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char *p, *type_name_dup;
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struct dm_exception_store_type *type;
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type = _get_exception_store_type(type_name);
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if (type)
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return type;
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type_name_dup = kstrdup(type_name, GFP_KERNEL);
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if (!type_name_dup) {
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DMERR("No memory left to attempt load for \"%s\"", type_name);
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return NULL;
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}
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while (request_module("dm-exstore-%s", type_name_dup) ||
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!(type = _get_exception_store_type(type_name))) {
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p = strrchr(type_name_dup, '-');
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if (!p)
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break;
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p[0] = '\0';
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}
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if (!type)
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DMWARN("Module for exstore type \"%s\" not found.", type_name);
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kfree(type_name_dup);
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return type;
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}
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static void put_type(struct dm_exception_store_type *type)
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{
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spin_lock(&_lock);
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module_put(type->module);
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spin_unlock(&_lock);
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}
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int dm_exception_store_type_register(struct dm_exception_store_type *type)
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{
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int r = 0;
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spin_lock(&_lock);
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if (!__find_exception_store_type(type->name))
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list_add(&type->list, &_exception_store_types);
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else
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r = -EEXIST;
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spin_unlock(&_lock);
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return r;
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}
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EXPORT_SYMBOL(dm_exception_store_type_register);
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int dm_exception_store_type_unregister(struct dm_exception_store_type *type)
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{
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spin_lock(&_lock);
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if (!__find_exception_store_type(type->name)) {
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spin_unlock(&_lock);
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return -EINVAL;
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}
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list_del(&type->list);
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spin_unlock(&_lock);
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return 0;
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}
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EXPORT_SYMBOL(dm_exception_store_type_unregister);
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int dm_exception_store_create(const char *type_name,
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struct dm_exception_store **store)
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{
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int r = 0;
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struct dm_exception_store_type *type;
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struct dm_exception_store *tmp_store;
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tmp_store = kmalloc(sizeof(*tmp_store), GFP_KERNEL);
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if (!tmp_store)
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return -ENOMEM;
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type = get_type(type_name);
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if (!type) {
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kfree(tmp_store);
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return -EINVAL;
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}
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tmp_store->type = type;
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r = type->ctr(tmp_store, 0, NULL);
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if (r) {
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put_type(type);
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kfree(tmp_store);
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return r;
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}
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*store = tmp_store;
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return 0;
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}
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EXPORT_SYMBOL(dm_exception_store_create);
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void dm_exception_store_destroy(struct dm_exception_store *store)
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{
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store->type->dtr(store);
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put_type(store->type);
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kfree(store);
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}
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EXPORT_SYMBOL(dm_exception_store_destroy);
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int dm_exception_store_init(void)
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{
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int r;
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@ -39,6 +39,9 @@ struct dm_snap_exception {
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*/
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struct dm_exception_store;
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struct dm_exception_store_type {
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const char *name;
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struct module *module;
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int (*ctr) (struct dm_exception_store *store,
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unsigned argc, char **argv);
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@ -85,10 +88,13 @@ struct dm_exception_store_type {
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void (*fraction_full) (struct dm_exception_store *store,
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sector_t *numerator,
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sector_t *denominator);
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/* For internal device-mapper use only. */
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struct list_head list;
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};
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struct dm_exception_store {
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struct dm_exception_store_type type;
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struct dm_exception_store_type *type;
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struct dm_snapshot *snap;
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@ -138,6 +144,13 @@ static inline void dm_consecutive_chunk_count_inc(struct dm_snap_exception *e)
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# endif
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int dm_exception_store_type_register(struct dm_exception_store_type *type);
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int dm_exception_store_type_unregister(struct dm_exception_store_type *type);
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int dm_exception_store_create(const char *type_name,
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struct dm_exception_store **store);
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void dm_exception_store_destroy(struct dm_exception_store *store);
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int dm_exception_store_init(void);
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void dm_exception_store_exit(void);
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@ -150,8 +163,4 @@ void dm_persistent_snapshot_exit(void);
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int dm_transient_snapshot_init(void);
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void dm_transient_snapshot_exit(void);
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int dm_create_persistent(struct dm_exception_store *store);
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int dm_create_transient(struct dm_exception_store *store);
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#endif /* _LINUX_DM_EXCEPTION_STORE */
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@ -478,7 +478,7 @@ static void persistent_fraction_full(struct dm_exception_store *store,
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*denominator = get_dev_size(store->snap->cow->bdev);
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}
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static void persistent_destroy(struct dm_exception_store *store)
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static void persistent_dtr(struct dm_exception_store *store)
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{
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struct pstore *ps = get_info(store);
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@ -656,7 +656,8 @@ static void persistent_drop_snapshot(struct dm_exception_store *store)
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DMWARN("write header failed");
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}
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int dm_create_persistent(struct dm_exception_store *store)
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static int persistent_ctr(struct dm_exception_store *store,
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unsigned argc, char **argv)
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{
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struct pstore *ps;
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@ -683,23 +684,69 @@ int dm_create_persistent(struct dm_exception_store *store)
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return -ENOMEM;
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}
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store->type.dtr = persistent_destroy;
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store->type.read_metadata = persistent_read_metadata;
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store->type.prepare_exception = persistent_prepare_exception;
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store->type.commit_exception = persistent_commit_exception;
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store->type.drop_snapshot = persistent_drop_snapshot;
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store->type.fraction_full = persistent_fraction_full;
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store->context = ps;
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return 0;
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}
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static int persistent_status(struct dm_exception_store *store,
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status_type_t status, char *result,
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unsigned int maxlen)
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{
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int sz = 0;
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return sz;
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}
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static struct dm_exception_store_type _persistent_type = {
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.name = "persistent",
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.module = THIS_MODULE,
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.ctr = persistent_ctr,
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.dtr = persistent_dtr,
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.read_metadata = persistent_read_metadata,
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.prepare_exception = persistent_prepare_exception,
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.commit_exception = persistent_commit_exception,
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.drop_snapshot = persistent_drop_snapshot,
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.fraction_full = persistent_fraction_full,
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.status = persistent_status,
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};
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static struct dm_exception_store_type _persistent_compat_type = {
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.name = "P",
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.module = THIS_MODULE,
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.ctr = persistent_ctr,
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.dtr = persistent_dtr,
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.read_metadata = persistent_read_metadata,
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.prepare_exception = persistent_prepare_exception,
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.commit_exception = persistent_commit_exception,
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.drop_snapshot = persistent_drop_snapshot,
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.fraction_full = persistent_fraction_full,
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.status = persistent_status,
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};
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int dm_persistent_snapshot_init(void)
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{
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return 0;
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int r;
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r = dm_exception_store_type_register(&_persistent_type);
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if (r) {
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DMERR("Unable to register persistent exception store type");
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return r;
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}
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r = dm_exception_store_type_register(&_persistent_compat_type);
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if (r) {
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DMERR("Unable to register old-style persistent exception "
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"store type");
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dm_exception_store_type_unregister(&_persistent_type);
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return r;
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}
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return r;
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}
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void dm_persistent_snapshot_exit(void)
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{
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dm_exception_store_type_unregister(&_persistent_type);
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dm_exception_store_type_unregister(&_persistent_compat_type);
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}
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@ -23,7 +23,7 @@ struct transient_c {
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sector_t next_free;
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};
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static void transient_destroy(struct dm_exception_store *store)
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static void transient_dtr(struct dm_exception_store *store)
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{
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kfree(store->context);
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}
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@ -67,17 +67,11 @@ static void transient_fraction_full(struct dm_exception_store *store,
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*denominator = get_dev_size(store->snap->cow->bdev);
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}
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int dm_create_transient(struct dm_exception_store *store)
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static int transient_ctr(struct dm_exception_store *store,
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unsigned argc, char **argv)
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{
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struct transient_c *tc;
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store->type.dtr = transient_destroy;
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store->type.read_metadata = transient_read_metadata;
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store->type.prepare_exception = transient_prepare_exception;
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store->type.commit_exception = transient_commit_exception;
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store->type.drop_snapshot = NULL;
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store->type.fraction_full = transient_fraction_full;
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tc = kmalloc(sizeof(struct transient_c), GFP_KERNEL);
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if (!tc)
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return -ENOMEM;
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@ -88,11 +82,62 @@ int dm_create_transient(struct dm_exception_store *store)
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return 0;
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}
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static int transient_status(struct dm_exception_store *store,
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status_type_t status, char *result,
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unsigned maxlen)
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{
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int sz = 0;
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return sz;
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}
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static struct dm_exception_store_type _transient_type = {
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.name = "transient",
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.module = THIS_MODULE,
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.ctr = transient_ctr,
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.dtr = transient_dtr,
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.read_metadata = transient_read_metadata,
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.prepare_exception = transient_prepare_exception,
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.commit_exception = transient_commit_exception,
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.fraction_full = transient_fraction_full,
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.status = transient_status,
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};
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static struct dm_exception_store_type _transient_compat_type = {
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.name = "N",
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.module = THIS_MODULE,
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.ctr = transient_ctr,
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.dtr = transient_dtr,
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.read_metadata = transient_read_metadata,
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.prepare_exception = transient_prepare_exception,
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.commit_exception = transient_commit_exception,
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.fraction_full = transient_fraction_full,
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.status = transient_status,
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};
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int dm_transient_snapshot_init(void)
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{
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return 0;
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int r;
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r = dm_exception_store_type_register(&_transient_type);
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if (r) {
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DMWARN("Unable to register transient exception store type");
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return r;
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}
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r = dm_exception_store_type_register(&_transient_compat_type);
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if (r) {
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DMWARN("Unable to register old-style transient "
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"exception store type");
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dm_exception_store_type_unregister(&_transient_type);
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return r;
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}
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return r;
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}
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void dm_transient_snapshot_exit(void)
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{
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dm_exception_store_type_unregister(&_transient_type);
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dm_exception_store_type_unregister(&_transient_compat_type);
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}
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@ -610,8 +610,6 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
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if (r)
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goto bad3;
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s->type = persistent;
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s->valid = 1;
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s->active = 0;
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atomic_set(&s->pending_exceptions_count, 0);
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@ -626,19 +624,15 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
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goto bad3;
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}
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s->store.snap = s;
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if (persistent == 'P')
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r = dm_create_persistent(&s->store);
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else
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r = dm_create_transient(&s->store);
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r = dm_exception_store_create(argv[2], &s->store);
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if (r) {
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ti->error = "Couldn't create exception store";
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r = -EINVAL;
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goto bad4;
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}
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s->store->snap = s;
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r = dm_kcopyd_client_create(SNAPSHOT_PAGES, &s->kcopyd_client);
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if (r) {
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ti->error = "Could not create kcopyd client";
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@ -665,7 +659,8 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
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spin_lock_init(&s->tracked_chunk_lock);
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/* Metadata must only be loaded into one table at once */
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r = s->store.type.read_metadata(&s->store, dm_add_exception, (void *)s);
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r = s->store->type->read_metadata(s->store, dm_add_exception,
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(void *)s);
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if (r < 0) {
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ti->error = "Failed to read snapshot metadata";
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goto bad_load_and_register;
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@ -700,7 +695,7 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
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dm_kcopyd_client_destroy(s->kcopyd_client);
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bad5:
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s->store.type.dtr(&s->store);
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s->store->type->dtr(s->store);
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bad4:
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exit_exception_table(&s->pending, pending_cache);
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@ -725,7 +720,7 @@ static void __free_exceptions(struct dm_snapshot *s)
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exit_exception_table(&s->pending, pending_cache);
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exit_exception_table(&s->complete, exception_cache);
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s->store.type.dtr(&s->store);
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s->store->type->dtr(s->store);
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}
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static void snapshot_dtr(struct dm_target *ti)
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@ -820,8 +815,8 @@ static void __invalidate_snapshot(struct dm_snapshot *s, int err)
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else if (err == -ENOMEM)
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DMERR("Invalidating snapshot: Unable to allocate exception.");
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if (s->store.type.drop_snapshot)
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s->store.type.drop_snapshot(&s->store);
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if (s->store->type->drop_snapshot)
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s->store->type->drop_snapshot(s->store);
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s->valid = 0;
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@ -943,8 +938,8 @@ static void copy_callback(int read_err, unsigned long write_err, void *context)
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else
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/* Update the metadata if we are persistent */
|
||||
s->store.type.commit_exception(&s->store, &pe->e,
|
||||
commit_callback, pe);
|
||||
s->store->type->commit_exception(s->store, &pe->e,
|
||||
commit_callback, pe);
|
||||
}
|
||||
|
||||
/*
|
||||
|
|
@ -1010,7 +1005,7 @@ __find_pending_exception(struct dm_snapshot *s,
|
|||
atomic_set(&pe->ref_count, 0);
|
||||
pe->started = 0;
|
||||
|
||||
if (s->store.type.prepare_exception(&s->store, &pe->e)) {
|
||||
if (s->store->type->prepare_exception(s->store, &pe->e)) {
|
||||
free_pending_exception(pe);
|
||||
return NULL;
|
||||
}
|
||||
|
|
@ -1149,11 +1144,11 @@ static int snapshot_status(struct dm_target *ti, status_type_t type,
|
|||
if (!snap->valid)
|
||||
snprintf(result, maxlen, "Invalid");
|
||||
else {
|
||||
if (snap->store.type.fraction_full) {
|
||||
if (snap->store->type->fraction_full) {
|
||||
sector_t numerator, denominator;
|
||||
snap->store.type.fraction_full(&snap->store,
|
||||
&numerator,
|
||||
&denominator);
|
||||
snap->store->type->fraction_full(snap->store,
|
||||
&numerator,
|
||||
&denominator);
|
||||
snprintf(result, maxlen, "%llu/%llu",
|
||||
(unsigned long long)numerator,
|
||||
(unsigned long long)denominator);
|
||||
|
|
@ -1169,9 +1164,9 @@ static int snapshot_status(struct dm_target *ti, status_type_t type,
|
|||
* to make private copies if the output is to
|
||||
* make sense.
|
||||
*/
|
||||
snprintf(result, maxlen, "%s %s %c %llu",
|
||||
snprintf(result, maxlen, "%s %s %s %llu",
|
||||
snap->origin->name, snap->cow->name,
|
||||
snap->type,
|
||||
snap->store->type->name,
|
||||
(unsigned long long)snap->chunk_size);
|
||||
break;
|
||||
}
|
||||
|
|
|
|||
|
|
@ -61,7 +61,7 @@ struct dm_snapshot {
|
|||
spinlock_t pe_lock;
|
||||
|
||||
/* The on disk metadata handler */
|
||||
struct dm_exception_store store;
|
||||
struct dm_exception_store *store;
|
||||
|
||||
struct dm_kcopyd_client *kcopyd_client;
|
||||
|
||||
|
|
|
|||
Loading…
Reference in New Issue