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Commit 5f274d88 authored by Joe Thornber's avatar Joe Thornber Committed by Mike Snitzer
Browse files

dm bio prison: introduce support for locking ranges of blocks 



Ranges will be placed in the same cell if they overlap.

Range locking is a prerequisite for more efficient multi-block discard
support in both the cache and thin-provisioning targets.

Signed-off-by: default avatarJoe Thornber <ejt@redhat.com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
parent f1afb36a

drivers/md/dm-bio-prison.c

+2 −2
Original line number Diff line number Diff line
@@ -95,10 +95,10 @@ static int cmp_keys(struct dm_cell_key *lhs, 
	if (lhs->dev > rhs->dev)

		return 1;



	if (lhs->block < rhs->block)

	if (lhs->block_end <= rhs->block_begin)

		return -1;



	if (lhs->block > rhs->block)

	if (lhs->block_begin >= rhs->block_end)

		return 1;



	return 0;

drivers/md/dm-bio-prison.h

+8 −4
Original line number Diff line number Diff line
@@ -23,11 +23,14 @@ 
 */

struct dm_bio_prison;



/* FIXME: this needs to be more abstract */

/*

 * Keys define a range of blocks within either a virtual or physical

 * device.

 */

struct dm_cell_key {

	int virtual;

	dm_thin_id dev;

	dm_block_t block;

	dm_block_t block_begin, block_end;

};



/*
@@ -59,7 +62,7 @@ void dm_bio_prison_free_cell(struct dm_bio_prison *prison, 
			     struct dm_bio_prison_cell *cell);



/*

 * Creates, or retrieves a cell for the given key.

 * Creates, or retrieves a cell that overlaps the given key.

 *

 * Returns 1 if pre-existing cell returned, zero if new cell created using

 * @cell_prealloc.
@@ -70,7 +73,8 @@ int dm_get_cell(struct dm_bio_prison *prison, 
		struct dm_bio_prison_cell **cell_result);



/*

 * An atomic op that combines retrieving a cell, and adding a bio to it.

 * An atomic op that combines retrieving or creating a cell, and adding a

 * bio to it.

 *

 * Returns 1 if the cell was already held, 0 if @inmate is the new holder.

 */

drivers/md/dm-cache-target.c

+2 −1
Original line number Diff line number Diff line
@@ -436,7 +436,8 @@ static void build_key(dm_oblock_t oblock, struct dm_cell_key *key) 
{

	key->virtual = 0;

	key->dev = 0;

	key->block = from_oblock(oblock);

	key->block_begin = from_oblock(oblock);

	key->block_end = key->block_begin + 1ULL;

}



/*

drivers/md/dm-thin.c

+4 −2
Original line number Diff line number Diff line
@@ -115,7 +115,8 @@ static void build_data_key(struct dm_thin_device *td, 
{

	key->virtual = 0;

	key->dev = dm_thin_dev_id(td);

	key->block = b;

	key->block_begin = b;

	key->block_end = b + 1ULL;

}



static void build_virtual_key(struct dm_thin_device *td, dm_block_t b,
@@ -123,7 +124,8 @@ static void build_virtual_key(struct dm_thin_device *td, dm_block_t b, 
{

	key->virtual = 1;

	key->dev = dm_thin_dev_id(td);

	key->block = b;

	key->block_begin = b;

	key->block_end = b + 1ULL;

}



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