Commit 3d5f6733 authored by Joe Thornber's avatar Joe Thornber Committed by Mike Snitzer
Browse files

dm thin metadata: speed up discard of partially mapped volumes 



Use dm_btree_lookup_next() to more quickly discard partially mapped
volumes.

Signed-off-by: default avatarJoe Thornber <ejt@redhat.com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
parent ed8b45a3

drivers/md/dm-thin-metadata.c

+41 −25
Original line number Diff line number Diff line
@@ -1395,6 +1395,19 @@ static bool __snapshotted_since(struct dm_thin_device *td, uint32_t time) 
	return td->snapshotted_time > time;

}



static void unpack_lookup_result(struct dm_thin_device *td, __le64 value,

				 struct dm_thin_lookup_result *result)

{

	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);

}



int dm_thin_find_block(struct dm_thin_device *td, dm_block_t block,

		       int can_issue_io, struct dm_thin_lookup_result *result)

{
@@ -1416,23 +1429,36 @@ int dm_thin_find_block(struct dm_thin_device *td, dm_block_t block, 
		info = &pmd->nb_info;



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

	if (!r) {

		uint64_t block_time = 0;

		dm_block_t exception_block;

		uint32_t exception_time;

	if (!r)

		unpack_lookup_result(td, value, result);



		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;

}



static int dm_thin_find_next_mapped_block(struct dm_thin_device *td, dm_block_t block,

					  dm_block_t *vblock,

					  struct dm_thin_lookup_result *result)

{

	int r;

	__le64 value;

	struct dm_pool_metadata *pmd = td->pmd;

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



	down_read(&pmd->root_lock);

	if (pmd->fail_io) {

		up_read(&pmd->root_lock);

		return -EINVAL;

	}



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

	if (!r)

		unpack_lookup_result(td, value, result);



	up_read(&pmd->root_lock);

	return r;

}



/* FIXME: write a more efficient one in btree */

int dm_thin_find_mapped_range(struct dm_thin_device *td,

			      dm_block_t begin, dm_block_t end,

			      dm_block_t *thin_begin, dm_block_t *thin_end,
@@ -1445,21 +1471,11 @@ int dm_thin_find_mapped_range(struct dm_thin_device *td, 
	if (end < begin)

		return -ENODATA;



	/*

	 * Find first mapped block.

	 */

	while (begin < end) {

		r = dm_thin_find_block(td, begin, true, &lookup);

		if (r) {

			if (r != -ENODATA)

	r = dm_thin_find_next_mapped_block(td, begin, &begin, &lookup);

	if (r)

		return r;

		} else

			break;



		begin++;

	}



	if (begin == end)

	if (begin >= end)

		return -ENODATA;



	*thin_begin = begin;