Commit e5cfc69a authored by Joe Thornber's avatar Joe Thornber Committed by Mike Snitzer
Browse files

dm thin metadata: change dm_thin_find_block to allow blocking, but not issuing, IO 



This change is a prerequisite for allowing metadata to be prefetched.

Signed-off-by: default avatarJoe Thornber <ejt@redhat.com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
parent a195db2d

drivers/md/dm-thin-metadata.c

+13 −17
Original line number Diff line number Diff line
@@ -1384,42 +1384,38 @@ static bool __snapshotted_since(struct dm_thin_device *td, uint32_t time) 
}



int dm_thin_find_block(struct dm_thin_device *td, dm_block_t block,

		       int can_block, struct dm_thin_lookup_result *result)

		       int can_issue_io, struct dm_thin_lookup_result *result)

{

	int r = -EINVAL;

	uint64_t block_time = 0;

	int r;

	__le64 value;

	struct dm_pool_metadata *pmd = td->pmd;

	dm_block_t keys[2] = { td->id, block };

	struct dm_btree_info *info;



	if (can_block) {

	if (pmd->fail_io)

		return -EINVAL;



	down_read(&pmd->root_lock);



	if (can_issue_io) {

		info = &pmd->info;

	} else if (down_read_trylock(&pmd->root_lock))

	} else

		info = &pmd->nb_info;

	else

		return -EWOULDBLOCK;



	if (pmd->fail_io)

		goto out;



	r = dm_btree_lookup(info, pmd->root, keys, &value);

	if (!r)

		block_time = le64_to_cpu(value);



out:

	up_read(&pmd->root_lock);



	if (!r) {

		uint64_t block_time = 0;

		dm_block_t exception_block;

		uint32_t exception_time;



		block_time = le64_to_cpu(value);

		unpack_block_time(block_time, &exception_block,

				  &exception_time);

		result->block = exception_block;

		result->shared = __snapshotted_since(td, exception_time);

	}



	up_read(&pmd->root_lock);

	return r;

}

drivers/md/dm-thin-metadata.h

+2 −2
Original line number Diff line number Diff line
@@ -139,12 +139,12 @@ struct dm_thin_lookup_result { 


/*

 * Returns:

 *   -EWOULDBLOCK iff @can_block is set and would block.

 *   -EWOULDBLOCK iff @can_issue_io is set and would issue IO

 *   -ENODATA iff that mapping is not present.

 *   0 success

 */

int dm_thin_find_block(struct dm_thin_device *td, dm_block_t block,

		       int can_block, struct dm_thin_lookup_result *result);

		       int can_issue_io, struct dm_thin_lookup_result *result);



/*

 * Obtain an unused block.