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Commit a5d895a9 authored by Joe Thornber's avatar Joe Thornber Committed by Mike Snitzer
Browse files

dm thin metadata: add dm_thin_find_mapped_range() 



Retrieve the next run of contiguously mapped blocks.  Useful for working
out where to break up IO.

Signed-off-by: default avatarJoe Thornber <ejt@redhat.com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
parent 4ec331c3

drivers/md/dm-thin-metadata.c

+57 −0
Original line number Diff line number Diff line
@@ -1417,6 +1417,63 @@ int dm_thin_find_block(struct dm_thin_device *td, dm_block_t block, 
	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,

			      dm_block_t *pool_begin, bool *maybe_shared)

{

	int r;

	dm_block_t pool_end;

	struct dm_thin_lookup_result lookup;



	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)

				return r;

		} else

			break;



		begin++;

	}



	if (begin == end)

		return -ENODATA;



	*thin_begin = begin;

	*pool_begin = lookup.block;

	*maybe_shared = lookup.shared;



	begin++;

	pool_end = *pool_begin + 1;

	while (begin != end) {

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

		if (r) {

			if (r == -ENODATA)

				break;

			else

				return r;

		}



		if ((lookup.block != pool_end) ||

		    (lookup.shared != *maybe_shared))

			break;



		pool_end++;

		begin++;

	}



	*thin_end = begin;

	return 0;

}



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

		    dm_block_t data_block)

{

drivers/md/dm-thin-metadata.h

+9 −0
Original line number Diff line number Diff line
@@ -146,6 +146,15 @@ struct dm_thin_lookup_result { 
int dm_thin_find_block(struct dm_thin_device *td, dm_block_t block,

		       int can_issue_io, struct dm_thin_lookup_result *result);



/*

 * Retrieve the next run of contiguously mapped blocks.  Useful for working

 * out where to break up IO.  Returns 0 on success, < 0 on error.

 */

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,

			      dm_block_t *pool_begin, bool *maybe_shared);



/*

 * Obtain an unused block.

 */