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Commit a159c1ac authored by Jonathan Brassow's avatar Jonathan Brassow Committed by Alasdair G Kergon
Browse files

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: default avatarJonathan Brassow <jbrassow@redhat.com>
Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
parent 4db6bfe0

drivers/md/dm-exception-store.c

+0 −1
Original line number Diff line number Diff line
@@ -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"

drivers/md/dm-exception-store.h

+10 −3
Original line number Diff line number Diff line
@@ -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.

	 */

drivers/md/dm-snap-persistent.c

+26 −16
Original line number Diff line number Diff line
@@ -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;

	}
@@ -548,7 +558,7 @@ static int persistent_read_metadata(struct dm_exception_store *store) 
	return 0;

}



static int persistent_prepare(struct dm_exception_store *store,

static int persistent_prepare_exception(struct dm_exception_store *store,

					struct dm_snap_exception *e)

{

	struct pstore *ps = get_info(store);
@@ -575,7 +585,7 @@ static int persistent_prepare(struct dm_exception_store *store, 
	return 0;

}



static void persistent_commit(struct dm_exception_store *store,

static void persistent_commit_exception(struct dm_exception_store *store,

					struct dm_snap_exception *e,

					void (*callback) (void *, int success),

					void *callback_context)
@@ -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;

drivers/md/dm-snap-transient.c

+12 −9
Original line number Diff line number Diff line
@@ -28,12 +28,15 @@ 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,

static int transient_prepare_exception(struct dm_exception_store *store,

				       struct dm_snap_exception *e)

{

	struct transient_c *tc = (struct transient_c *) store->context;
@@ -48,7 +51,7 @@ static int transient_prepare(struct dm_exception_store *store, 
	return 0;

}



static void transient_commit(struct dm_exception_store *store,

static void transient_commit_exception(struct dm_exception_store *store,

				       struct dm_snap_exception *e,

				       void (*callback) (void *, int success),

				       void *callback_context)
@@ -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;

drivers/md/dm-snap.c

+7 −2
Original line number Diff line number Diff line
@@ -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;