dm snapshot: extend exception store functions
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>
diff --git a/drivers/md/dm-exception-store.c b/drivers/md/dm-exception-store.c
index 74777e0..dccbfb0 100644
--- a/drivers/md/dm-exception-store.c
+++ b/drivers/md/dm-exception-store.c
@@ -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"
diff --git a/drivers/md/dm-exception-store.h b/drivers/md/dm-exception-store.h
index 78d1ace..bb9f33d 100644
--- a/drivers/md/dm-exception-store.h
+++ b/drivers/md/dm-exception-store.h
@@ -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 @@
* COW device).
*/
struct dm_exception_store {
-
/*
* Destroys this object when you've finished with it.
*/
@@ -45,9 +45,13 @@
/*
* 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 @@
*/
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.
*/
diff --git a/drivers/md/dm-snap-persistent.c b/drivers/md/dm-snap-persistent.c
index 57c946c..936b34e 100644
--- a/drivers/md/dm-snap-persistent.c
+++ b/drivers/md/dm-snap-persistent.c
@@ -395,7 +395,11 @@
* '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 @@
/*
* 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 @@
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 @@
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 @@
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 @@
/*
* Read the metadata.
*/
- r = read_exceptions(ps);
+ r = read_exceptions(ps, callback, callback_context);
if (r)
return r;
}
@@ -548,8 +558,8 @@
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 @@
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 @@
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 @@
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;
diff --git a/drivers/md/dm-snap-transient.c b/drivers/md/dm-snap-transient.c
index 2a781df..7f6e2e6 100644
--- a/drivers/md/dm-snap-transient.c
+++ b/drivers/md/dm-snap-transient.c
@@ -28,13 +28,16 @@
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 @@
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 @@
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;
diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c
index 018b567..65ff82f 100644
--- a/drivers/md/dm-snap.c
+++ b/drivers/md/dm-snap.c
@@ -430,8 +430,13 @@
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 @@
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;
diff --git a/drivers/md/dm-snap.h b/drivers/md/dm-snap.h
index 9281236..d9e62b4 100644
--- a/drivers/md/dm-snap.h
+++ b/drivers/md/dm-snap.h
@@ -76,12 +76,6 @@
};
/*
- * 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)