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Commit 7c3d3f2a authored by Joe Thornber's avatar Joe Thornber Committed by Alasdair G Kergon
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dm persistent data: add threshold callback to space map 



Add a threshold callback function to the persistent data space map
interface for a subsequent patch to use.

dm-thin and dm-cache are interested in knowing when they're getting
low on metadata or data blocks.  This patch introduces a new method
for registering a callback against a threshold.

Signed-off-by: default avatarJoe Thornber <ejt@redhat.com>
Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
parent 24347e95

drivers/md/persistent-data/dm-space-map-disk.c

+2 −1
Original line number Original line Diff line number Diff line
@@ -248,7 +248,8 @@ static struct dm_space_map ops = { 
	.new_block = sm_disk_new_block,

	.new_block = sm_disk_new_block,

	.commit = sm_disk_commit,

	.commit = sm_disk_commit,

	.root_size = sm_disk_root_size,

	.root_size = sm_disk_root_size,

	.copy_root = sm_disk_copy_root

	.copy_root = sm_disk_copy_root,

	.register_threshold_callback = NULL

};

};





struct dm_space_map *dm_sm_disk_create(struct dm_transaction_manager *tm,

struct dm_space_map *dm_sm_disk_create(struct dm_transaction_manager *tm,

drivers/md/persistent-data/dm-space-map-metadata.c

+4 −2
Original line number Original line Diff line number Diff line
@@ -391,7 +391,8 @@ static struct dm_space_map ops = { 
	.new_block = sm_metadata_new_block,

	.new_block = sm_metadata_new_block,

	.commit = sm_metadata_commit,

	.commit = sm_metadata_commit,

	.root_size = sm_metadata_root_size,

	.root_size = sm_metadata_root_size,

	.copy_root = sm_metadata_copy_root

	.copy_root = sm_metadata_copy_root,

	.register_threshold_callback = NULL

};

};





/*----------------------------------------------------------------*/

/*----------------------------------------------------------------*/
@@ -513,7 +514,8 @@ static struct dm_space_map bootstrap_ops = { 
	.new_block = sm_bootstrap_new_block,

	.new_block = sm_bootstrap_new_block,

	.commit = sm_bootstrap_commit,

	.commit = sm_bootstrap_commit,

	.root_size = sm_bootstrap_root_size,

	.root_size = sm_bootstrap_root_size,

	.copy_root = sm_bootstrap_copy_root

	.copy_root = sm_bootstrap_copy_root,

	.register_threshold_callback = NULL

};

};





/*----------------------------------------------------------------*/

/*----------------------------------------------------------------*/

drivers/md/persistent-data/dm-space-map.h

+23 −0
Original line number Original line Diff line number Diff line
@@ -9,6 +9,8 @@ 




#include "dm-block-manager.h"

#include "dm-block-manager.h"





typedef void (*dm_sm_threshold_fn)(void *context);



/*

/*

 * struct dm_space_map keeps a record of how many times each block in a device

 * struct dm_space_map keeps a record of how many times each block in a device

 * is referenced.  It needs to be fixed on disk as part of the transaction.

 * is referenced.  It needs to be fixed on disk as part of the transaction.
@@ -59,6 +61,15 @@ struct dm_space_map { 
	 */

	 */

	int (*root_size)(struct dm_space_map *sm, size_t *result);

	int (*root_size)(struct dm_space_map *sm, size_t *result);

	int (*copy_root)(struct dm_space_map *sm, void *copy_to_here_le, size_t len);

	int (*copy_root)(struct dm_space_map *sm, void *copy_to_here_le, size_t len);



	/*

	 * You can register one threshold callback which is edge-triggered

	 * when the free space in the space map drops below the threshold.

	 */

	int (*register_threshold_callback)(struct dm_space_map *sm,

					   dm_block_t threshold,

					   dm_sm_threshold_fn fn,

					   void *context);

};

};





/*----------------------------------------------------------------*/

/*----------------------------------------------------------------*/
@@ -131,4 +142,16 @@ static inline int dm_sm_copy_root(struct dm_space_map *sm, void *copy_to_here_le 
	return sm->copy_root(sm, copy_to_here_le, len);

	return sm->copy_root(sm, copy_to_here_le, len);

}

}





static inline int dm_sm_register_threshold_callback(struct dm_space_map *sm,

						    dm_block_t threshold,

						    dm_sm_threshold_fn fn,

						    void *context)

{

	if (sm->register_threshold_callback)

		return sm->register_threshold_callback(sm, threshold, fn, context);



	return -EINVAL;

}





#endif	/* _LINUX_DM_SPACE_MAP_H */
 
#endif	/* _LINUX_DM_SPACE_MAP_H */