Commit 086fbbbd authored by Joe Thornber's avatar Joe Thornber Committed by Mike Snitzer
Browse files

dm thin metadata: make dm_thin_find_mapped_range() atomic 



Refactor dm_thin_find_mapped_range() so that it takes the read lock on
the metadata's lock; rather than relying on finer grained locking that
is pushed down inside dm_thin_find_next_mapped_block() and
dm_thin_find_block().

Signed-off-by: default avatarJoe Thornber <ejt@redhat.com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
parent 3d5f6733

drivers/md/dm-thin-metadata.c

+43 −21
Original line number Diff line number Diff line
@@ -1408,7 +1408,7 @@ static void unpack_lookup_result(struct dm_thin_device *td, __le64 value, 
	result->shared = __snapshotted_since(td, exception_time);

}



int dm_thin_find_block(struct dm_thin_device *td, dm_block_t block,

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

			int can_issue_io, struct dm_thin_lookup_result *result)

{

	int r;
@@ -1417,12 +1417,6 @@ int dm_thin_find_block(struct dm_thin_device *td, dm_block_t block, 
	dm_block_t keys[2] = { td->id, block };

	struct dm_btree_info *info;



	down_read(&pmd->root_lock);

	if (pmd->fail_io) {

		up_read(&pmd->root_lock);

		return -EINVAL;

	}



	if (can_issue_io) {

		info = &pmd->info;

	} else
@@ -1432,18 +1426,14 @@ int dm_thin_find_block(struct dm_thin_device *td, dm_block_t block, 
	if (!r)

		unpack_lookup_result(td, value, result);



	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 dm_thin_find_block(struct dm_thin_device *td, dm_block_t block,

		       int can_issue_io, 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) {
@@ -1451,15 +1441,29 @@ static int dm_thin_find_next_mapped_block(struct dm_thin_device *td, dm_block_t 
		return -EINVAL;

	}



	r = __find_block(td, block, can_issue_io, result);



	up_read(&pmd->root_lock);

	return r;

}



static int __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 };



	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;

}



int dm_thin_find_mapped_range(struct dm_thin_device *td,

static int __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)
@@ -1471,7 +1475,7 @@ int dm_thin_find_mapped_range(struct dm_thin_device *td, 
	if (end < begin)

		return -ENODATA;



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

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

	if (r)

		return r;
@@ -1485,7 +1489,7 @@ int dm_thin_find_mapped_range(struct dm_thin_device *td, 
	begin++;

	pool_end = *pool_begin + 1;

	while (begin != end) {

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

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

		if (r) {

			if (r == -ENODATA)

				break;
@@ -1505,6 +1509,24 @@ int dm_thin_find_mapped_range(struct dm_thin_device *td, 
	return 0;

}



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 = -EINVAL;

	struct dm_pool_metadata *pmd = td->pmd;



	down_read(&pmd->root_lock);

	if (!pmd->fail_io) {

		r = __find_mapped_range(td, begin, end, thin_begin, thin_end,

					pool_begin, maybe_shared);

	}

	up_read(&pmd->root_lock);



	return r;

}



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

		    dm_block_t data_block)

{

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