I've tried to make some more progress on this front. I've added the
'status' function to the API and greatly expanded the possibilities for
the constructor table. I like this version a lot better, but I've run
into a snag and I need some advice before I proceed.
I've been successful in removing dm-snap.h - which means that there is
no cross referencing between dm-exception-store and dm-snap. dm-snap
needs dm-exception-store, but not the other way around... except in one
case. When the persistent exception store reads metadata, it must
populate the snapshot's cache. I don't want to reference 'struct
dm_snapshot' in dm_exception_store.c.
So, I can do 3 things:
1) leave dm-snap.h basically for no other reason other than the
'dm_add_exception' function. Keep all other changes (you'll have to
push pretty hard to make me give up all the advantages gained in the
constructor).
2) Specify a callback function and (void *)snapshot to
'dm_exception_store_create' so that I can generically induce an action
in the snapshot code without having to know anything about it.
3) Push more of the functionality found in dm-snap.c into
dm-exception-store.c - potentially adding more functions to the new API
- to eliminate the need for dm-exception-store to know about dm-snap
Right now, I'm leaning toward #1. It allows me to change the least
amount of code, while allowing me to defer the decision on #2 and #3 to
later.
Please provide feedback. (Even if that just means you are looking at
it... otherwise, I will simply proceed with #1.)
brassow
Create exception store API.
Index: linux-2.6/drivers/md/dm-exception-store.h
===================================================================
--- linux-2.6.orig/drivers/md/dm-exception-store.h
+++ linux-2.6/drivers/md/dm-exception-store.h
@@ -11,6 +11,7 @@
#ifdef __KERNEL__
#include <linux/blkdev.h>
+#include <linux/device-mapper.h>
/*
* The snapshot code deals with largish chunks of the disk at a
@@ -76,15 +77,42 @@ static inline void dm_consecutive_chunk_
# endif
/*
- * Abstraction to handle the meta/layout of exception stores (the
- * COW device).
+ * Return the number of sectors in the device.
*/
+static inline sector_t get_dev_size(struct block_device *bdev)
+{
+ return bdev->bd_inode->i_size >> SECTOR_SHIFT;
+}
+
+
+struct dm_exception_store_type;
struct dm_exception_store {
+ struct dm_exception_store_type *type;
+ struct dm_target *ti;
- /*
- * Destroys this object when you've finished with it.
- */
- void (*destroy) (struct dm_exception_store *store);
+ struct dm_dev *cow;
+
+ /* 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;
+};
+
+static inline chunk_t sector_to_chunk(struct dm_exception_store *store,
+ sector_t sector)
+{
+ return (sector & ~store->chunk_mask) >> store->chunk_shift;
+}
+
+struct dm_exception_store_type {
+ const char *name;
+ struct module *module;
+
+ int (*ctr) (struct dm_exception_store *store,
+ unsigned argc, char **argv);
+ void (*dtr) (struct dm_exception_store *store);
/*
* The target shouldn't read the COW device until this is
@@ -118,16 +146,20 @@ struct dm_exception_store {
sector_t *numerator,
sector_t *denominator);
- struct dm_snapshot *snap;
- void *context;
+ int (*status) (struct dm_exception_store *store, status_type_t status,
+ char *result, unsigned int maxlen);
};
-/*
- * Constructor and destructor for the exception stores
- */
-int dm_create_persistent(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,
+ unsigned argc, char **argv,
+ struct dm_exception_store **store);
+void dm_exception_store_destroy(struct dm_exception_store *store);
-int dm_create_transient(struct dm_exception_store *store);
+int dm_exception_store_init(void);
+void dm_exception_store_exit(void);
#endif /* __KERNEL__ */
Index: linux-2.6/drivers/md/dm-exception-store.c
===================================================================
--- linux-2.6.orig/drivers/md/dm-exception-store.c
+++ linux-2.6/drivers/md/dm-exception-store.c
@@ -8,7 +8,6 @@
*/
#include "dm-exception-store.h"
-#include "dm-snap.h"
#include <linux/mm.h>
#include <linux/pagemap.h>
@@ -17,9 +16,329 @@
#include <linux/dm-io.h>
#include <linux/dm-kcopyd.h>
-#define DM_MSG_PREFIX "snapshots"
+#define DM_MSG_PREFIX "dm-exception-store"
#define DM_CHUNK_SIZE_DEFAULT_SECTORS 32 /* 16KB */
+struct dm_exception_store_internal {
+ struct dm_exception_store_type *type;
+
+ struct list_head list;
+ long use;
+};
+
+static LIST_HEAD(_exception_store_types);
+static DEFINE_SPINLOCK(_lock);
+
+static struct dm_exception_store_internal *
+__find_exception_store_type(const char *name)
+{
+ struct dm_exception_store_internal *internal_type;
+
+ list_for_each_entry(internal_type, &_exception_store_types, list)
+ if (!strcmp(name, internal_type->type->name))
+ return internal_type;
+
+ return NULL;
+}
+
+static struct dm_exception_store_internal *
+_get_exception_store_type(const char *name)
+{
+ struct dm_exception_store_internal *internal_type;
+
+ spin_lock(&_lock);
+
+ internal_type = __find_exception_store_type(name);
+ if (internal_type) {
+ if (!internal_type->use &&
+ !try_module_get(internal_type->type->module))
+ internal_type = NULL;
+ else
+ internal_type->use++;
+ }
+
+ spin_unlock(&_lock);
+
+ return internal_type;
+}
+
+/*
+ * FIXME:
+ * FIXME:
+ * FIXME:
+ *
+ * 'dm-exception-store-<module>' is too long of a name in my
+ * opinion, which is why I've chosen to have the files
+ * containing exception store implementations be 'dm-exstore-<module>'
+ *
+ * This is your chance to disagree....
+ *
+ * FIXME:
+ * FIXME:
+ * FIXME: (You see this by now, right? :)
+ */
+
+/*
+ * get_type
+ * @type_name
+ *
+ * Attempt to retrieve the dm_exception_store_type by name. If not already
+ * available, attempt to load the appropriate module.
+ *
+ * Exstore modules are named "dm-exstore-" followed by the 'type_name'.
+ * Modules may contain multiple types.
+ * This function will first try the module "dm-exstore-<type_name>",
+ * then truncate 'type_name' on the last '-' and try again.
+ *
+ * For example, if type_name was "clustered-shared", it would search
+ * 'dm-exstore-clustered-shared' then 'dm-exstore-clustered'.
+ *
+ * Returns: dm_exception_store_type* on success, NULL on failure
+ */
+static struct dm_exception_store_type *get_type(const char *type_name)
+{
+ char *p, *type_name_dup;
+ struct dm_exception_store_internal *internal_type;
+
+ if (!type_name)
+ return NULL;
+
+ internal_type = _get_exception_store_type(type_name);
+ if (internal_type)
+ return internal_type->type;
+
+ type_name_dup = kstrdup(type_name, GFP_KERNEL);
+ if (!type_name_dup) {
+ DMWARN("No memory left to attempt load for \"%s\"",
+ type_name);
+ return NULL;
+ }
+
+ while (request_module("dm-exstore-%s", type_name_dup) ||
+ !(internal_type = _get_exception_store_type(type_name))) {
+ p = strrchr(type_name_dup, '-');
+ if (!p)
+ break;
+ p[0] = '\0';
+ }
+
+ if (!internal_type)
+ DMWARN("Module for exstore type \"%s\" found.", type_name);
+
+ kfree(type_name_dup);
+
+ return internal_type ? internal_type->type : NULL;
+}
+
+static void put_type(struct dm_exception_store_type *type)
+{
+ struct dm_exception_store_internal *internal_type;
+
+ if (!type)
+ return;
+
+ spin_lock(&_lock);
+ internal_type = __find_exception_store_type(type->name);
+ if (!internal_type)
+ goto out;
+
+ if (!--internal_type->use)
+ module_put(type->module);
+
+ BUG_ON(internal_type->use < 0);
+
+out:
+ spin_unlock(&_lock);
+}
+
+static struct dm_exception_store_internal *
+_alloc_exception_store_type(struct dm_exception_store_type *type)
+{
+ struct dm_exception_store_internal *internal_type;
+
+ internal_type = kzalloc(sizeof(*internal_type), GFP_KERNEL);
+
+ if (internal_type)
+ internal_type->type = type;
+
+ return internal_type;
+}
+
+int dm_exception_store_type_register(struct dm_exception_store_type *type)
+{
+ struct dm_exception_store_internal *internal_type;
+ int r = 0;
+
+ internal_type = _alloc_exception_store_type(type);
+
+ if (!internal_type)
+ return -ENOMEM;
+
+ spin_lock(&_lock);
+ if (!__find_exception_store_type(type->name))
+ list_add(&internal_type->list, &_exception_store_types);
+ else {
+ kfree(internal_type);
+ r = -EEXIST;
+ }
+ spin_unlock(&_lock);
+
+ return r;
+}
+EXPORT_SYMBOL(dm_exception_store_type_register);
+
+int dm_exception_store_type_unregister(struct dm_exception_store_type *type)
+{
+ struct dm_exception_store_internal *internal_type;
+
+ spin_lock(&_lock);
+
+ internal_type = __find_exception_store_type(type->name);
+ if (!internal_type) {
+ spin_unlock(&_lock);
+ return -EINVAL;
+ }
+
+ if (internal_type->use) {
+ spin_unlock(&_lock);
+ return -ETXTBSY;
+ }
+
+ list_del(&internal_type->list);
+
+ spin_unlock(&_lock);
+ kfree(internal_type);
+
+ return 0;
+}
+EXPORT_SYMBOL(dm_exception_store_type_unregister);
+
+/*
+ * 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;
+ char *value;
+
+ chunk_size = simple_strtoul(chunk_size_arg, &value, 10);
+ if (*chunk_size_arg == '\0' || *value != '\0') {
+ *error = "Invalid chunk size";
+ return -EINVAL;
+ }
+
+ if (!chunk_size) {
+ 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 = round_up(chunk_size, PAGE_SIZE >> 9);
+
+ /* Check chunk_size is a power of 2 */
+ if (!is_power_of_2(chunk_size)) {
+ *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(store->cow->bdev) >> 9)) {
+ *error = "Chunk size is not a multiple of device blocksize";
+ return -EINVAL;
+ }
+
+ store->chunk_size = chunk_size;
+ store->chunk_mask = chunk_size - 1;
+ store->chunk_shift = ffs(chunk_size) - 1;
+
+ return 0;
+}
+
+int dm_exception_store_create(const char *type_name, struct dm_target *ti,
+ unsigned int argc, char **argv,
+ struct dm_exception_store **store)
+{
+ int r = 0;
+ struct dm_exception_store_type *type;
+ struct dm_exception_store *tmp_store;
+
+ if (argc < 2) {
+ ti->error = "Insufficient exception store arguments";
+ return -EINVAL;
+ }
+
+ tmp_store = kmalloc(sizeof(*tmp_store), GFP_KERNEL);
+ if (!tmp_store)
+ return -ENOMEM;
+
+ type = get_type(type_name);
+ if (!type) {
+ kfree(tmp_store);
+ return -EINVAL;
+ }
+
+ tmp_store->type = type;
+ tmp_store->ti = ti;
+
+ r = dm_get_device(ti, argv[0], 0, 0,
+ FMODE_READ | FMODE_WRITE, &tmp_store->cow);
+ if (r) {
+ ti->error = "Cannot get COW device";
+ put_type(type);
+ kfree(tmp_store);
+ return r;
+ }
+
+ r = set_chunk_size(tmp_store, argv[1], &ti->error);
+ if (r) {
+ dm_put_device(ti, tmp_store->cow);
+ put_type(type);
+ kfree(tmp_store);
+ return r;
+ }
+
+ /*
+ * COW-dev and chunk_size are common to all types of
+ * exception stores and are stored directly in the
+ * dm_exception_store and not passed on to the
+ * constructor for the dm_exception_store_type
+ */
+ argc -= 2;
+ argv += 2;
+
+ r = type->ctr(tmp_store, argc, argv);
+ if (r) {
+ dm_put_device(ti, tmp_store->cow);
+ put_type(type);
+ kfree(tmp_store);
+ return r;
+ }
+
+ *store = tmp_store;
+ return 0;
+}
+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);
+}
+EXPORT_SYMBOL(dm_exception_store_destroy);
+
/*-----------------------------------------------------------------
* Persistent snapshots, by persistent we mean that the snapshot
* will survive a reboot.
@@ -92,7 +411,7 @@ struct commit_callback {
* The top level structure for a persistent exception store.
*/
struct pstore {
- struct dm_snapshot *snap; /* up pointer to my snapshot */
+ struct dm_exception_store *store;
int version;
int valid;
uint32_t exceptions_per_area;
@@ -144,7 +463,7 @@ static int alloc_area(struct pstore *ps)
int r = -ENOMEM;
size_t len;
- len = ps->snap->chunk_size << SECTOR_SHIFT;
+ len = ps->store->chunk_size << SECTOR_SHIFT;
/*
* Allocate the chunk_size block of memory that will hold
@@ -192,9 +511,9 @@ static void do_metadata(struct work_stru
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,
+ .bdev = ps->store->cow->bdev,
+ .sector = ps->store->chunk_size * chunk,
+ .count = ps->store->chunk_size,
};
struct dm_io_request io_req = {
.bi_rw = rw,
@@ -250,15 +569,15 @@ static int area_io(struct pstore *ps, in
static void zero_memory_area(struct pstore *ps)
{
- memset(ps->area, 0, ps->snap->chunk_size << SECTOR_SHIFT);
+ memset(ps->area, 0, ps->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,
+ .bdev = ps->store->cow->bdev,
+ .sector = ps->store->chunk_size * area_location(ps, area),
+ .count = ps->store->chunk_size,
};
struct dm_io_request io_req = {
.bi_rw = WRITE,
@@ -281,15 +600,15 @@ static int read_header(struct pstore *ps
/*
* 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,
- 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;
+ if (!ps->store->chunk_size) {
+ ps->store->chunk_size = max(DM_CHUNK_SIZE_DEFAULT_SECTORS,
+ bdev_hardsect_size(ps->store->cow->bdev) >> 9);
+ ps->store->chunk_mask = ps->store->chunk_size - 1;
+ ps->store->chunk_shift = ffs(ps->store->chunk_size) - 1;
chunk_size_supplied = 0;
}
- ps->io_client = dm_io_client_create(sectors_to_pages(ps->snap->
+ ps->io_client = dm_io_client_create(sectors_to_pages(ps->store->
chunk_size));
if (IS_ERR(ps->io_client))
return PTR_ERR(ps->io_client);
@@ -320,22 +639,22 @@ static int read_header(struct pstore *ps
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->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->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->store->chunk_size = chunk_size;
+ ps->store->chunk_mask = chunk_size - 1;
+ ps->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->store->chunk_size),
ps->io_client);
if (r)
return r;
@@ -352,13 +671,13 @@ static int write_header(struct pstore *p
{
struct disk_header *dh;
- memset(ps->area, 0, ps->snap->chunk_size << SECTOR_SHIFT);
+ memset(ps->area, 0, ps->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->store->chunk_size);
return chunk_io(ps, 0, WRITE, 1);
}
@@ -470,11 +789,44 @@ static struct pstore *get_info(struct dm
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;
- *denominator = get_dev_size(store->snap->cow->bdev);
+ *numerator = get_info(store)->next_free * store->chunk_size;
+ *denominator = get_dev_size(store->cow->bdev);
}
-static void persistent_destroy(struct dm_exception_store *store)
+static int persistent_ctr(struct dm_exception_store *store,
+ unsigned argc, char **argv)
+{
+ struct pstore *ps;
+
+ /* allocate the pstore */
+ ps = kmalloc(sizeof(*ps), GFP_KERNEL);
+ if (!ps)
+ return -ENOMEM;
+
+ ps->store = store;
+ ps->valid = 1;
+ ps->version = SNAPSHOT_DISK_VERSION;
+ ps->area = NULL;
+ ps->next_free = 2; /* skipping the header and first area */
+ ps->current_committed = 0;
+
+ ps->callback_count = 0;
+ atomic_set(&ps->pending_count, 0);
+ ps->callbacks = NULL;
+
+ ps->metadata_wq = create_singlethread_workqueue("ksnaphd");
+ if (!ps->metadata_wq) {
+ kfree(ps);
+ DMERR("couldn't start header metadata update thread");
+ return -ENOMEM;
+ }
+
+ store->context = ps;
+
+ return 0;
+}
+
+static void persistent_dtr(struct dm_exception_store *store)
{
struct pstore *ps = get_info(store);
@@ -500,7 +852,7 @@ static int persistent_read_metadata(stru
/*
* Now we know correct chunk_size, complete the initialisation.
*/
- ps->exceptions_per_area = (ps->snap->chunk_size << SECTOR_SHIFT) /
+ ps->exceptions_per_area = (ps->store->chunk_size << SECTOR_SHIFT) /
sizeof(struct disk_exception);
ps->callbacks = dm_vcalloc(ps->exceptions_per_area,
sizeof(*ps->callbacks));
@@ -551,16 +903,16 @@ static int persistent_read_metadata(stru
return 0;
}
-static int persistent_prepare(struct dm_exception_store *store,
- struct dm_snap_exception *e)
+static int persistent_prepare_exception(struct dm_exception_store *store,
+ struct dm_snap_exception *e)
{
struct pstore *ps = get_info(store);
uint32_t stride;
chunk_t next_free;
- sector_t size = get_dev_size(store->snap->cow->bdev);
+ sector_t size = get_dev_size(store->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;
@@ -578,10 +930,10 @@ static int persistent_prepare(struct dm_
return 0;
}
-static void persistent_commit(struct dm_exception_store *store,
- struct dm_snap_exception *e,
- void (*callback) (void *, int success),
- void *callback_context)
+static void persistent_commit_exception(struct dm_exception_store *store,
+ struct dm_snap_exception *e,
+ void (*callback) (void *, int success),
+ void *callback_context)
{
unsigned int i;
struct pstore *ps = get_info(store);
@@ -640,7 +992,7 @@ static void persistent_commit(struct dm_
ps->callback_count = 0;
}
-static void persistent_drop(struct dm_exception_store *store)
+static void persistent_drop_snapshot(struct dm_exception_store *store)
{
struct pstore *ps = get_info(store);
@@ -649,44 +1001,41 @@ static void persistent_drop(struct dm_ex
DMWARN("write header failed");
}
-int dm_create_persistent(struct dm_exception_store *store)
-{
- struct pstore *ps;
-
- /* allocate the pstore */
- ps = kmalloc(sizeof(*ps), GFP_KERNEL);
- if (!ps)
- return -ENOMEM;
+static int persistent_status(struct dm_exception_store *store,
+ status_type_t status, char *result,
+ unsigned int maxlen)
+{
+ int sz = 0;
+
+ switch(status) {
+ case STATUSTYPE_INFO:
+ break;
+ case STATUSTYPE_TABLE:
+ DMEMIT("persistent 2 %s %llu", store->cow->name,
+ (unsigned long long)store->chunk_size);
+ }
- ps->snap = store->snap;
- ps->valid = 1;
- ps->version = SNAPSHOT_DISK_VERSION;
- ps->area = NULL;
- ps->next_free = 2; /* skipping the header and first area */
- ps->current_committed = 0;
+ return sz;
+}
- ps->callback_count = 0;
- atomic_set(&ps->pending_count, 0);
- ps->callbacks = NULL;
+static int persistent_status_bc(struct dm_exception_store *store,
+ status_type_t status, char *result,
+ unsigned int maxlen)
+{
+ int sz = 0;
- ps->metadata_wq = create_singlethread_workqueue("ksnaphd");
- if (!ps->metadata_wq) {
- kfree(ps);
- DMERR("couldn't start header metadata update thread");
- return -ENOMEM;
+ switch(status) {
+ case STATUSTYPE_INFO:
+ break;
+ case STATUSTYPE_TABLE:
+ DMEMIT("%s p %llu", store->cow->name,
+ (unsigned long long)store->chunk_size);
}
- store->destroy = persistent_destroy;
- store->read_metadata = persistent_read_metadata;
- store->prepare_exception = persistent_prepare;
- store->commit_exception = persistent_commit;
- store->drop_snapshot = persistent_drop;
- store->fraction_full = persistent_fraction_full;
- store->context = ps;
-
- return 0;
+ return sz;
}
+
/*-----------------------------------------------------------------
* Implementation of the store for non-persistent snapshots.
*---------------------------------------------------------------*/
@@ -694,7 +1043,31 @@ struct transient_c {
sector_t next_free;
};
-static void transient_destroy(struct dm_exception_store *store)
+/*
+ * transient_ctr
+ * @store
+ * @argc
+ * @argv: Always <COW-dev> <chunk-size>
+ *
+ * Returns: 0 on success, -Exxx on error
+ */
+static int transient_ctr(struct dm_exception_store *store,
+ unsigned argc, char **argv)
+{
+ struct transient_c *tc;
+
+ tc = kmalloc(sizeof(struct transient_c), GFP_KERNEL);
+ if (!tc)
+ return -ENOMEM;
+
+ tc->next_free = 0;
+ store->context = tc;
+
+ return 0;
+
+}
+
+static void transient_dtr(struct dm_exception_store *store)
{
kfree(store->context);
}
@@ -704,25 +1077,25 @@ static int transient_read_metadata(struc
return 0;
}
-static int transient_prepare(struct dm_exception_store *store,
- struct dm_snap_exception *e)
+static int transient_prepare_exception(struct dm_exception_store *store,
+ struct dm_snap_exception *e)
{
struct transient_c *tc = (struct transient_c *) store->context;
- sector_t size = get_dev_size(store->snap->cow->bdev);
+ sector_t size = get_dev_size(store->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;
+ e->new_chunk = sector_to_chunk(store, tc->next_free);
+ tc->next_free += store->chunk_size;
return 0;
}
-static void transient_commit(struct dm_exception_store *store,
- struct dm_snap_exception *e,
- void (*callback) (void *, int success),
- void *callback_context)
+static void transient_commit_exception(struct dm_exception_store *store,
+ struct dm_snap_exception *e,
+ void (*callback) (void *, int success),
+ void *callback_context)
{
/* Just succeed */
callback(callback_context, 1);
@@ -732,26 +1105,145 @@ static void transient_fraction_full(stru
sector_t *numerator, sector_t *denominator)
{
*numerator = ((struct transient_c *) store->context)->next_free;
- *denominator = get_dev_size(store->snap->cow->bdev);
+ *denominator = get_dev_size(store->cow->bdev);
}
-int dm_create_transient(struct dm_exception_store *store)
+static int transient_status(struct dm_exception_store *store,
+ status_type_t status, char *result,
+ unsigned int maxlen)
{
- struct transient_c *tc;
+ int sz = 0;
- store->destroy = transient_destroy;
- store->read_metadata = transient_read_metadata;
- store->prepare_exception = transient_prepare;
- store->commit_exception = transient_commit;
- store->drop_snapshot = NULL;
- store->fraction_full = transient_fraction_full;
+ switch(status) {
+ case STATUSTYPE_INFO:
+ break;
+ case STATUSTYPE_TABLE:
+ DMEMIT("transient 2 %s %llu", store->cow->name,
+ (unsigned long long)store->chunk_size);
+ }
- tc = kmalloc(sizeof(struct transient_c), GFP_KERNEL);
- if (!tc)
- return -ENOMEM;
+ return sz;
+}
- tc->next_free = 0;
- store->context = tc;
+static int transient_status_bc(struct dm_exception_store *store,
+ status_type_t status, char *result,
+ unsigned int maxlen)
+{
+ int sz = 0;
- return 0;
+ switch(status) {
+ case STATUSTYPE_INFO:
+ break;
+ case STATUSTYPE_TABLE:
+ DMEMIT("%s n %llu", store->cow->name,
+ (unsigned long long)store->chunk_size);
+ }
+
+ return sz;
+}
+
+static struct dm_exception_store_type _persistent_type = {
+ .name = "persistent",
+ .module = THIS_MODULE,
+ .ctr = persistent_ctr,
+ .dtr = persistent_dtr,
+ .read_metadata = persistent_read_metadata,
+ .prepare_exception = persistent_prepare_exception,
+ .commit_exception = persistent_commit_exception,
+ .drop_snapshot = persistent_drop_snapshot,
+ .fraction_full = persistent_fraction_full,
+ .status = persistent_status,
+};
+
+/* This structure for backwards compatibility */
+static struct dm_exception_store_type _persistent_type_bc = {
+ .name = "p",
+ .module = THIS_MODULE,
+ .ctr = persistent_ctr,
+ .dtr = persistent_dtr,
+ .read_metadata = persistent_read_metadata,
+ .prepare_exception = persistent_prepare_exception,
+ .commit_exception = persistent_commit_exception,
+ .drop_snapshot = persistent_drop_snapshot,
+ .fraction_full = persistent_fraction_full,
+ .status = persistent_status_bc,
+};
+
+static struct dm_exception_store_type _transient_type = {
+ .name = "transient",
+ .module = THIS_MODULE,
+ .ctr = transient_ctr,
+ .dtr = transient_dtr,
+ .read_metadata = transient_read_metadata,
+ .prepare_exception = transient_prepare_exception,
+ .commit_exception = transient_commit_exception,
+ .fraction_full = transient_fraction_full,
+ .status = transient_status,
+};
+
+/* This structure for backwards compatibility */
+static struct dm_exception_store_type _transient_type_bc = {
+ .name = "t",
+ .module = THIS_MODULE,
+ .ctr = transient_ctr,
+ .dtr = transient_dtr,
+ .read_metadata = transient_read_metadata,
+ .prepare_exception = transient_prepare_exception,
+ .commit_exception = transient_commit_exception,
+ .fraction_full = transient_fraction_full,
+ .status = transient_status_bc,
+};
+
+int dm_exception_store_init(void)
+{
+ int r;
+
+ /* Register the standard old-school types */
+ r = dm_exception_store_type_register(&_transient_type);
+ if (r) {
+ DMWARN("Unable to register transient exception store type");
+ return r;
+ }
+
+ r = dm_exception_store_type_register(&_transient_type_bc);
+ if (r) {
+ DMWARN("Unable to register transient exception store type");
+ dm_exception_store_type_unregister(&_transient_type);
+ return r;
+ }
+
+ r = dm_exception_store_type_register(&_persistent_type);
+ if (r) {
+ DMWARN("Unable to register presistent exception store type");
+ dm_exception_store_type_unregister(&_transient_type);
+ dm_exception_store_type_unregister(&_transient_type_bc);
+ return r;
+ }
+
+ r = dm_exception_store_type_register(&_persistent_type_bc);
+ if (r) {
+ DMWARN("Unable to register presistent exception store type");
+ dm_exception_store_type_unregister(&_transient_type);
+ dm_exception_store_type_unregister(&_transient_type_bc);
+ dm_exception_store_type_unregister(&_persistent_type);
+ }
+
+ return r;
+}
+
+void dm_exception_store_exit(void)
+{
+ dm_exception_store_type_unregister(&_transient_type);
+ dm_exception_store_type_unregister(&_transient_type_bc);
+ dm_exception_store_type_unregister(&_persistent_type);
+ dm_exception_store_type_unregister(&_persistent_type_bc);
}
+
+/*
+ * We could easily make this a module, but I think we'd like
+ * the snapshot module to load the initial exception stores.
+ *
+MODULE_DESCRIPTION(DM_NAME " exception store");
+MODULE_AUTHOR("<dm-devel@xxxxxxxxxx>");
+MODULE_LICENCE("GPL");
+*/
Index: linux-2.6/drivers/md/dm-snap.c
===================================================================
--- linux-2.6.orig/drivers/md/dm-snap.c
+++ linux-2.6/drivers/md/dm-snap.c
@@ -19,9 +19,9 @@
#include <linux/vmalloc.h>
#include <linux/log2.h>
#include <linux/dm-kcopyd.h>
+#include <linux/workqueue.h>
#include "dm-exception-store.h"
-#include "dm-snap.h"
#include "dm-bio-list.h"
#define DM_MSG_PREFIX "snapshots"
@@ -46,9 +46,82 @@
*/
#define MIN_IOS 256
+#define DM_TRACKED_CHUNK_HASH_SIZE 16
+#define DM_TRACKED_CHUNK_HASH(x) ((unsigned long)(x) & \
+ (DM_TRACKED_CHUNK_HASH_SIZE - 1))
+
+struct exception_table {
+ uint32_t hash_mask;
+ unsigned hash_shift;
+ struct list_head *table;
+};
+
+struct dm_snapshot {
+ struct rw_semaphore lock;
+ struct dm_target *ti;
+
+ struct dm_dev *origin;
+
+ /* List of snapshots per Origin */
+ struct list_head list;
+
+ /* You can't use a snapshot if this is 0 (e.g. if full) */
+ int valid;
+
+ /* Origin writes don't trigger exceptions until this is set */
+ int active;
+
+ mempool_t *pending_pool;
+
+ atomic_t pending_exceptions_count;
+
+ struct exception_table pending;
+ struct exception_table complete;
+
+ /*
+ * pe_lock protects all pending_exception operations and access
+ * as well as the snapshot_bios list.
+ */
+ spinlock_t pe_lock;
+
+ /* The on disk metadata handler */
+ struct dm_exception_store *store;
+
+ struct dm_kcopyd_client *kcopyd_client;
+
+ /* Queue of snapshot writes for ksnapd to flush */
+ struct bio_list queued_bios;
+ struct work_struct queued_bios_work;
+
+ /* Chunks with outstanding reads */
+ mempool_t *tracked_chunk_pool;
+ spinlock_t tracked_chunk_lock;
+ struct hlist_head tracked_chunk_hash[DM_TRACKED_CHUNK_HASH_SIZE];
+};
+
static struct workqueue_struct *ksnapd;
static void flush_queued_bios(struct work_struct *work);
+/*
+ * Used by the exception stores to load exceptions hen
+ * initialising.
+ */
+int dm_add_exception(struct dm_snapshot *s, chunk_t old, chunk_t new);
+
+static inline sector_t chunk_to_sector(struct dm_snapshot *s, chunk_t chunk)
+{
+ return chunk << s->store->chunk_shift;
+}
+
+static inline int bdev_equal(struct block_device *lhs, struct block_device *rhs)
+{
+ /*
+ * There is only ever one instance of a particular block
+ * device so we can compare pointers safely.
+ */
+ return lhs == rhs;
+}
+
struct dm_snap_pending_exception {
struct dm_snap_exception e;
@@ -470,11 +543,11 @@ static int init_hash_tables(struct dm_sn
* Calculate based on the size of the original volume or
* the COW volume...
*/
- cow_dev_size = get_dev_size(s->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) >> s->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);
@@ -499,113 +572,112 @@ static int init_hash_tables(struct dm_sn
}
/*
- * Round a number up to the nearest 'size' boundary. size must
- * be a power of 2.
+ * create_exception_store
+ * @ti
+ * @argc
+ * @argv
+ * @args_used
+ * @store: contains newly allocated dm_exception_store
+ *
+ * Possible formats for argv::
+ * Backwards compatibility mode:
+ * <COW-dev> p/n <chunk-size>
+ * Current format:
+ * <store type> <arg count> <COW> <chunk-size> [other args]
+ *
+ * Returns: 0 on success, -Exxx on error
*/
-static ulong round_up(ulong n, ulong size)
+static int create_exception_store(struct dm_target *ti, unsigned argc,
+ char **argv, unsigned *args_used,
+ struct dm_exception_store **store)
{
- size--;
- return (n + size) & ~size;
-}
+ unsigned param_count;
+ char *tmp_argv[2];
-static int set_chunk_size(struct dm_snapshot *s, const char *chunk_size_arg,
- char **error)
-{
- unsigned long chunk_size;
- char *value;
+ *store = NULL;
- chunk_size = simple_strtoul(chunk_size_arg, &value, 10);
- if (*chunk_size_arg == '\0' || *value != '\0') {
- *error = "Invalid chunk size";
- return -EINVAL;
- }
+ if (!strcasecmp("p", argv[1]) || !strcasecmp("t", argv[1])) {
+ /* backwards compatibility translation */
- if (!chunk_size) {
- s->chunk_size = s->chunk_mask = s->chunk_shift = 0;
- return 0;
- }
+ if (argc < 3) {
+ ti->error = "Insufficient exception store arguments";
+ return -EINVAL;
+ }
- /*
- * Chunk size must be multiple of page size. Silently
- * round up if it's not.
- */
- chunk_size = round_up(chunk_size, PAGE_SIZE >> 9);
+ tmp_argv[0] = argv[0]; /* COW dev */
+ tmp_argv[1] = argv[2]; /* chunk size */
- /* Check chunk_size is a power of 2 */
- if (!is_power_of_2(chunk_size)) {
- *error = "Chunk size is not a power of 2";
- return -EINVAL;
+ *args_used = 3;
+
+ return dm_exception_store_create(argv[1], ti, 2, tmp_argv, store);
}
- /* Validate the chunk size against the device block size */
- if (chunk_size % (bdev_hardsect_size(s->cow->bdev) >> 9)) {
- *error = "Chunk size is not a multiple of device blocksize";
+ if (sscanf(argv[1], "%u", ¶m_count) != 1) {
+ ti->error = "Invalid exception store argument count";
return -EINVAL;
}
- s->chunk_size = chunk_size;
- s->chunk_mask = chunk_size - 1;
- s->chunk_shift = ffs(chunk_size) - 1;
+ *args_used = 2 + param_count;
- return 0;
+ if (argc < *args_used) {
+ ti->error = "Insufficient exception store arguments";
+ return -EINVAL;
+ }
+
+ return dm_exception_store_create(argv[0], ti, param_count, argv + 2, store);
}
/*
- * Construct a snapshot mapping: <origin_dev> <COW-dev> <p/n> <chunk-size>
+ * snapshot_ctr
+ * @ti
+ * @argc
+ * @argv
+ *
+ * Construct a snapshot mapping. Possible mapping tables include:
+ * <origin_dev> <exception store args> <feature args>
+ * See 'create_exception_store' for format of <exception store args>.
+ *
+ * Returns: 0 on success, -XXX on error
*/
static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
{
struct dm_snapshot *s;
- int i;
+ int i = 0;
int r = -EINVAL;
- char persistent;
char *origin_path;
- char *cow_path;
+ unsigned args_used;
+ struct dm_exception_store *store;
- if (argc != 4) {
- ti->error = "requires exactly 4 arguments";
- r = -EINVAL;
- goto bad1;
+ if (argc < 4) {
+ ti->error = "too few arguments";
+ return -EINVAL;
}
origin_path = argv[0];
- cow_path = argv[1];
- persistent = toupper(*argv[2]);
+ argv++;
+ argc--;
+ r = create_exception_store(ti, argc, argv, &args_used, &store);
+ if (r)
+ return r;
- if (persistent != 'P' && persistent != 'N') {
- ti->error = "Persistent flag is not P or N";
- r = -EINVAL;
- goto bad1;
- }
+ argc -= args_used;
+ argv += args_used;
s = kmalloc(sizeof(*s), GFP_KERNEL);
if (s == NULL) {
- ti->error = "Cannot allocate snapshot context private "
- "structure";
+ ti->error = "Cannot allocate snapshot private structure";
r = -ENOMEM;
goto bad1;
}
+ s->store = store;
+
r = dm_get_device(ti, origin_path, 0, ti->len, FMODE_READ, &s->origin);
if (r) {
ti->error = "Cannot get origin device";
goto bad2;
}
- r = dm_get_device(ti, cow_path, 0, 0,
- FMODE_READ | FMODE_WRITE, &s->cow);
- if (r) {
- dm_put_device(ti, s->origin);
- ti->error = "Cannot get COW device";
- goto bad2;
- }
-
- r = set_chunk_size(s, argv[3], &ti->error);
- if (r)
- goto bad3;
-
- s->type = persistent;
-
s->valid = 1;
s->active = 0;
atomic_set(&s->pending_exceptions_count, 0);
@@ -620,29 +692,16 @@ static int snapshot_ctr(struct dm_target
goto bad3;
}
- s->store.snap = s;
-
- if (persistent == 'P')
- r = dm_create_persistent(&s->store);
- else
- r = dm_create_transient(&s->store);
-
- if (r) {
- ti->error = "Couldn't create exception store";
- r = -EINVAL;
- goto bad4;
- }
-
r = dm_kcopyd_client_create(SNAPSHOT_PAGES, &s->kcopyd_client);
if (r) {
ti->error = "Could not create kcopyd client";
- goto bad5;
+ goto bad4;
}
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 bad5;
}
s->tracked_chunk_pool = mempool_create_slab_pool(MIN_IOS,
@@ -650,7 +709,7 @@ static int snapshot_ctr(struct dm_target
if (!s->tracked_chunk_pool) {
ti->error = "Could not allocate tracked_chunk mempool for "
"tracking reads";
- goto bad_tracked_chunk_pool;
+ goto bad6;
}
for (i = 0; i < DM_TRACKED_CHUNK_HASH_SIZE; i++)
@@ -659,10 +718,10 @@ static int snapshot_ctr(struct dm_target
spin_lock_init(&s->tracked_chunk_lock);
/* Metadata must only be loaded into one table at once */
- r = s->store.read_metadata(&s->store);
+ r = s->store->type->read_metadata(s->store);
if (r < 0) {
ti->error = "Failed to read snapshot metadata";
- goto bad_load_and_register;
+ goto bad7;
} else if (r > 0) {
s->valid = 0;
DMWARN("Snapshot is marked invalid.");
@@ -676,38 +735,29 @@ static int snapshot_ctr(struct dm_target
if (register_snapshot(s)) {
r = -EINVAL;
ti->error = "Cannot register snapshot origin";
- goto bad_load_and_register;
+ goto bad7;
}
ti->private = s;
- ti->split_io = s->chunk_size;
+ ti->split_io = s->store->chunk_size;
return 0;
- bad_load_and_register:
+bad7:
mempool_destroy(s->tracked_chunk_pool);
-
- bad_tracked_chunk_pool:
+bad6:
mempool_destroy(s->pending_pool);
-
- bad6:
+bad5:
dm_kcopyd_client_destroy(s->kcopyd_client);
-
- bad5:
- s->store.destroy(&s->store);
-
- bad4:
+bad4:
exit_exception_table(&s->pending, pending_cache);
exit_exception_table(&s->complete, exception_cache);
-
- bad3:
- dm_put_device(ti, s->cow);
+bad3:
dm_put_device(ti, s->origin);
-
- bad2:
+bad2:
kfree(s);
-
- bad1:
+bad1:
+ dm_exception_store_destroy(s->store);
return r;
}
@@ -719,7 +769,7 @@ static void __free_exceptions(struct dm_
exit_exception_table(&s->pending, pending_cache);
exit_exception_table(&s->complete, exception_cache);
- s->store.destroy(&s->store);
+ s->store->type->dtr(s->store);
}
static void snapshot_dtr(struct dm_target *ti)
@@ -755,7 +805,6 @@ static void snapshot_dtr(struct dm_targe
mempool_destroy(s->pending_pool);
dm_put_device(ti, s->origin);
- dm_put_device(ti, s->cow);
kfree(s);
}
@@ -814,8 +863,8 @@ static void __invalidate_snapshot(struct
else if (err == -ENOMEM)
DMERR("Invalidating snapshot: Unable to allocate exception.");
- if (s->store.drop_snapshot)
- s->store.drop_snapshot(&s->store);
+ if (s->store->type->drop_snapshot)
+ s->store->type->drop_snapshot(s->store);
s->valid = 0;
@@ -937,8 +986,8 @@ static void copy_callback(int read_err,
else
/* Update the metadata if we are persistent */
- s->store.commit_exception(&s->store, &pe->e, commit_callback,
- pe);
+ s->store->type->commit_exception(s->store, &pe->e,
+ commit_callback, pe);
}
/*
@@ -955,9 +1004,9 @@ static void start_copy(struct dm_snap_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.bdev = s->store->cow->bdev;
dest.sector = chunk_to_sector(s, pe->e.new_chunk);
dest.count = src.count;
@@ -979,7 +1028,7 @@ __find_pending_exception(struct dm_snaps
{
struct dm_snap_exception *e;
struct dm_snap_pending_exception *pe;
- chunk_t chunk = sector_to_chunk(s, bio->bi_sector);
+ chunk_t chunk = sector_to_chunk(s->store, bio->bi_sector);
/*
* Is there a pending exception for this already ?
@@ -1018,7 +1067,7 @@ __find_pending_exception(struct dm_snaps
atomic_set(&pe->ref_count, 0);
pe->started = 0;
- if (s->store.prepare_exception(&s->store, &pe->e)) {
+ if (s->store->type->prepare_exception(s->store, &pe->e)) {
free_pending_exception(pe);
return NULL;
}
@@ -1033,10 +1082,10 @@ __find_pending_exception(struct dm_snaps
static void remap_exception(struct dm_snapshot *s, struct dm_snap_exception *e,
struct bio *bio, chunk_t chunk)
{
- bio->bi_bdev = s->cow->bdev;
+ bio->bi_bdev = s->store->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,
@@ -1048,7 +1097,7 @@ static int snapshot_map(struct dm_target
chunk_t chunk;
struct dm_snap_pending_exception *pe = NULL;
- chunk = sector_to_chunk(s, bio->bi_sector);
+ chunk = sector_to_chunk(s->store, bio->bi_sector);
/* Full snapshots are not usable */
/* To get here the table must be live so s->active is always set. */
@@ -1131,24 +1180,25 @@ static void snapshot_resume(struct dm_ta
static int snapshot_status(struct dm_target *ti, status_type_t type,
char *result, unsigned int maxlen)
{
+ int sz = 0;
struct dm_snapshot *snap = ti->private;
switch (type) {
case STATUSTYPE_INFO:
if (!snap->valid)
- snprintf(result, maxlen, "Invalid");
+ DMEMIT("Invalid");
else {
- if (snap->store.fraction_full) {
+ if (snap->store->type->fraction_full) {
sector_t numerator, denominator;
- snap->store.fraction_full(&snap->store,
- &numerator,
- &denominator);
- snprintf(result, maxlen, "%llu/%llu",
- (unsigned long long)numerator,
- (unsigned long long)denominator);
+ snap->store->type->fraction_full(snap->store,
+ &numerator,
+ &denominator);
+ DMEMIT("%llu/%llu",
+ (unsigned long long)numerator,
+ (unsigned long long)denominator);
}
else
- snprintf(result, maxlen, "Unknown");
+ DMEMIT("Unknown");
}
break;
@@ -1158,10 +1208,9 @@ static int snapshot_status(struct dm_tar
* to make private copies if the output is to
* make sense.
*/
- snprintf(result, maxlen, "%s %s %c %llu",
- snap->origin->name, snap->cow->name,
- snap->type,
- (unsigned long long)snap->chunk_size);
+ DMEMIT("%s", snap->origin->name);
+ snap->store->type->status(snap->store, type, result, maxlen);
+
break;
}
@@ -1197,7 +1246,7 @@ static int __origin_write(struct list_he
* Remember, different snapshots can have
* different chunk sizes.
*/
- chunk = sector_to_chunk(snap, bio->bi_sector);
+ chunk = sector_to_chunk(snap->store, bio->bi_sector);
/*
* Check exception table to see if block
@@ -1354,7 +1403,7 @@ static void origin_resume(struct dm_targ
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;
@@ -1405,10 +1454,16 @@ static int __init dm_snapshot_init(void)
{
int r;
+ r = dm_exception_store_init();
+ if (r) {
+ DMERR("Failed to initialize exception stores");
+ return r;
+ }
+
r = dm_register_target(&snapshot_target);
if (r) {
DMERR("snapshot target register failed %d", r);
- return r;
+ goto bad0;
}
r = dm_register_target(&origin_target);
@@ -1465,6 +1520,8 @@ static int __init dm_snapshot_init(void)
dm_unregister_target(&origin_target);
bad1:
dm_unregister_target(&snapshot_target);
+ bad0:
+ dm_exception_store_exit();
return r;
}
@@ -1486,6 +1543,8 @@ static void __exit dm_snapshot_exit(void
kmem_cache_destroy(pending_cache);
kmem_cache_destroy(exception_cache);
kmem_cache_destroy(tracked_chunk_cache);
+
+ dm_exception_store_exit();
}
/* Module hooks */
Index: linux-2.6/drivers/md/dm-snap.h
===================================================================
--- linux-2.6.orig/drivers/md/dm-snap.h
+++ /dev/null
@@ -1,112 +0,0 @@
-/*
- * dm-snapshot.c
- *
- * Copyright (C) 2001-2002 Sistina Software (UK) Limited.
- *
- * This file is released under the GPL.
- */
-
-#ifndef DM_SNAPSHOT_H
-#define DM_SNAPSHOT_H
-
-#include <linux/device-mapper.h>
-#include "dm-bio-list.h"
-#include <linux/blkdev.h>
-#include <linux/workqueue.h>
-
-struct exception_table {
- uint32_t hash_mask;
- unsigned hash_shift;
- struct list_head *table;
-};
-
-#define DM_TRACKED_CHUNK_HASH_SIZE 16
-#define DM_TRACKED_CHUNK_HASH(x) ((unsigned long)(x) & \
- (DM_TRACKED_CHUNK_HASH_SIZE - 1))
-
-struct dm_snapshot {
- struct rw_semaphore lock;
- struct dm_target *ti;
-
- struct dm_dev *origin;
- struct dm_dev *cow;
-
- /* 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;
-
- /* Origin writes don't trigger exceptions until this is set */
- int active;
-
- /* Used for display of table */
- char type;
-
- mempool_t *pending_pool;
-
- atomic_t pending_exceptions_count;
-
- struct exception_table pending;
- struct exception_table complete;
-
- /*
- * pe_lock protects all pending_exception operations and access
- * as well as the snapshot_bios list.
- */
- spinlock_t pe_lock;
-
- /* The on disk metadata handler */
- struct dm_exception_store store;
-
- struct dm_kcopyd_client *kcopyd_client;
-
- /* Queue of snapshot writes for ksnapd to flush */
- struct bio_list queued_bios;
- struct work_struct queued_bios_work;
-
- /* Chunks with outstanding reads */
- mempool_t *tracked_chunk_pool;
- spinlock_t tracked_chunk_lock;
- struct hlist_head tracked_chunk_hash[DM_TRACKED_CHUNK_HASH_SIZE];
-};
-
-/*
- * Used by the exception stores to load exceptions hen
- * initialising.
- */
-int dm_add_exception(struct dm_snapshot *s, chunk_t old, chunk_t new);
-
-/*
- * Return the number of sectors in the device.
- */
-static inline sector_t get_dev_size(struct block_device *bdev)
-{
- return bdev->bd_inode->i_size >> SECTOR_SHIFT;
-}
-
-static inline chunk_t sector_to_chunk(struct dm_snapshot *s, sector_t sector)
-{
- return (sector & ~s->chunk_mask) >> s->chunk_shift;
-}
-
-static inline sector_t chunk_to_sector(struct dm_snapshot *s, chunk_t chunk)
-{
- return chunk << s->chunk_shift;
-}
-
-static inline int bdev_equal(struct block_device *lhs, struct block_device *rhs)
-{
- /*
- * There is only ever one instance of a particular block
- * device so we can compare pointers safely.
- */
- return lhs == rhs;
-}
-
-#endif
--
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