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dm snapshot: extend exception store functions

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Supply dm_add_exception as a callback to the read_metadata function.
Add a status function ready for a later patch and name the functions
consistently.

Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
This commit is contained in:
Jonathan Brassow 2009-01-06 03:05:19 +00:00 committed by Alasdair G Kergon
parent 4db6bfe02b
commit a159c1ac5f
6 changed files with 55 additions and 37 deletions
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1
drivers/md/dm-exception-store.c
View File

@ -11,7 +11,6 @@
#include <linux/pagemap.h>
#include <linux/vmalloc.h>
#include <linux/slab.h>
#include <linux/device-mapper.h>
#define DM_MSG_PREFIX "snapshot exception stores"

13
drivers/md/dm-exception-store.h
View File

@ -11,6 +11,7 @@
#define _LINUX_DM_EXCEPTION_STORE
#include <linux/blkdev.h>
#include <linux/device-mapper.h>
/*
* The snapshot code deals with largish chunks of the disk at a
@ -37,7 +38,6 @@ struct dm_snap_exception {
* COW device).
*/
struct dm_exception_store {
/*
* Destroys this object when you've finished with it.
*/
@ -45,9 +45,13 @@ struct dm_exception_store {
/*
* The target shouldn't read the COW device until this is
* called.
* called. As exceptions are read from the COW, they are
* reported back via the callback.
*/
int (*read_metadata) (struct dm_exception_store *store);
int (*read_metadata) (struct dm_exception_store *store,
int (*callback)(void *callback_context,
chunk_t old, chunk_t new),
void *callback_context);
/*
* Find somewhere to store the next exception.
@ -68,6 +72,9 @@ struct dm_exception_store {
*/
void (*drop_snapshot) (struct dm_exception_store *store);
int (*status) (struct dm_exception_store *store, status_type_t status,
char *result, unsigned int maxlen);
/*
* Return how full the snapshot is.
*/

42
drivers/md/dm-snap-persistent.c
View File

@ -395,7 +395,11 @@ static void write_exception(struct pstore *ps,
* 'full' is filled in to indicate if the area has been
* filled.
*/
static int insert_exceptions(struct pstore *ps, int *full)
static int insert_exceptions(struct pstore *ps,
int (*callback)(void *callback_context,
chunk_t old, chunk_t new),
void *callback_context,
int *full)
{
int r;
unsigned int i;
@ -428,7 +432,7 @@ static int insert_exceptions(struct pstore *ps, int *full)
/*
* Otherwise we add the exception to the snapshot.
*/
r = dm_add_exception(ps->snap, de.old_chunk, de.new_chunk);
r = callback(callback_context, de.old_chunk, de.new_chunk);
if (r)
return r;
}
@ -436,7 +440,10 @@ static int insert_exceptions(struct pstore *ps, int *full)
return 0;
}
static int read_exceptions(struct pstore *ps)
static int read_exceptions(struct pstore *ps,
int (*callback)(void *callback_context, chunk_t old,
chunk_t new),
void *callback_context)
{
int r, full = 1;
@ -449,7 +456,7 @@ static int read_exceptions(struct pstore *ps)
if (r)
return r;
r = insert_exceptions(ps, &full);
r = insert_exceptions(ps, callback, callback_context, &full);
if (r)
return r;
}
@ -482,7 +489,10 @@ static void persistent_destroy(struct dm_exception_store *store)
kfree(ps);
}
static int persistent_read_metadata(struct dm_exception_store *store)
static int persistent_read_metadata(struct dm_exception_store *store,
int (*callback)(void *callback_context,
chunk_t old, chunk_t new),
void *callback_context)
{
int r, uninitialized_var(new_snapshot);
struct pstore *ps = get_info(store);
@ -540,7 +550,7 @@ static int persistent_read_metadata(struct dm_exception_store *store)
/*
* Read the metadata.
*/
r = read_exceptions(ps);
r = read_exceptions(ps, callback, callback_context);
if (r)
return r;
}
@ -548,8 +558,8 @@ static int persistent_read_metadata(struct dm_exception_store *store)
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;
@ -575,10 +585,10 @@ static int persistent_prepare(struct dm_exception_store *store,
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);
@ -637,7 +647,7 @@ static void persistent_commit(struct dm_exception_store *store,
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);
@ -675,9 +685,9 @@ int dm_create_persistent(struct dm_exception_store *store)
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->prepare_exception = persistent_prepare_exception;
store->commit_exception = persistent_commit_exception;
store->drop_snapshot = persistent_drop_snapshot;
store->fraction_full = persistent_fraction_full;
store->context = ps;

21
drivers/md/dm-snap-transient.c
View File

@ -28,13 +28,16 @@ static void transient_destroy(struct dm_exception_store *store)
kfree(store->context);
}
static int transient_read_metadata(struct dm_exception_store *store)
static int transient_read_metadata(struct dm_exception_store *store,
int (*callback)(void *callback_context,
chunk_t old, chunk_t new),
void *callback_context)
{
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);
@ -48,10 +51,10 @@ static int transient_prepare(struct dm_exception_store *store,
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);
@ -70,8 +73,8 @@ int dm_create_transient(struct dm_exception_store *store)
store->destroy = transient_destroy;
store->read_metadata = transient_read_metadata;
store->prepare_exception = transient_prepare;
store->commit_exception = transient_commit;
store->prepare_exception = transient_prepare_exception;
store->commit_exception = transient_commit_exception;
store->drop_snapshot = NULL;
store->fraction_full = transient_fraction_full;

9
drivers/md/dm-snap.c
View File

@ -430,8 +430,13 @@ out:
list_add(&new_e->hash_list, e ? &e->hash_list : l);
}
int dm_add_exception(struct dm_snapshot *s, chunk_t old, chunk_t new)
/*
* Callback used by the exception stores to load exceptions when
* initialising.
*/
static int dm_add_exception(void *context, chunk_t old, chunk_t new)
{
struct dm_snapshot *s = context;
struct dm_snap_exception *e;
e = alloc_exception();
@ -660,7 +665,7 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv)
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.read_metadata(&s->store, dm_add_exception, (void *)s);
if (r < 0) {
ti->error = "Failed to read snapshot metadata";
goto bad_load_and_register;

6
drivers/md/dm-snap.h
View File

@ -75,12 +75,6 @@ struct dm_snapshot {
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.
*/