Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 993ceab9 authored by Joe Thornber's avatar Joe Thornber Committed by Mike Snitzer
Browse files

dm thin metadata: fix bug in dm_thin_remove_range() 



dm_btree_remove_leaves() only unmaps a contiguous region so we need a
loop, in __remove_range(), to handle ranges that contain multiple
regions.

A new btree function, dm_btree_lookup_next(), is introduced which is
more efficiently able to skip over regions of the thin device which
aren't mapped.  __remove_range() uses dm_btree_lookup_next() for each
iteration of __remove_range()'s loop.

Also, improve description of dm_btree_remove_leaves().

Fixes: 6550f075 ("dm thin metadata: add dm_thin_remove_range()")
Signed-off-by: default avatarJoe Thornber <ejt@redhat.com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org # 4.1+
parent 30ce6e1c

drivers/md/dm-thin-metadata.c

+23 −5
Original line number Diff line number Diff line
@@ -1538,7 +1538,7 @@ static int __remove(struct dm_thin_device *td, dm_block_t block) 
static int __remove_range(struct dm_thin_device *td, dm_block_t begin, dm_block_t end)

{

	int r;

	unsigned count;

	unsigned count, total_count = 0;

	struct dm_pool_metadata *pmd = td->pmd;

	dm_block_t keys[1] = { td->id };

	__le64 value;
@@ -1561,11 +1561,29 @@ static int __remove_range(struct dm_thin_device *td, dm_block_t begin, dm_block_ 
	if (r)

		return r;



	/*

	 * Remove leaves stops at the first unmapped entry, so we have to

	 * loop round finding mapped ranges.

	 */

	while (begin < end) {

		r = dm_btree_lookup_next(&pmd->bl_info, mapping_root, &begin, &begin, &value);

		if (r == -ENODATA)

			break;



		if (r)

			return r;



		if (begin >= end)

			break;



		r = dm_btree_remove_leaves(&pmd->bl_info, mapping_root, &begin, end, &mapping_root, &count);

		if (r)

			return r;



	td->mapped_blocks -= count;

		total_count += count;

	}



	td->mapped_blocks -= total_count;

	td->changed = 1;



	/*

drivers/md/persistent-data/dm-btree.c

+81 −0
Original line number Diff line number Diff line
@@ -63,6 +63,11 @@ int lower_bound(struct btree_node *n, uint64_t key) 
	return bsearch(n, key, 0);

}



static int upper_bound(struct btree_node *n, uint64_t key)

{

	return bsearch(n, key, 1);

}



void inc_children(struct dm_transaction_manager *tm, struct btree_node *n,

		  struct dm_btree_value_type *vt)

{
@@ -392,6 +397,82 @@ int dm_btree_lookup(struct dm_btree_info *info, dm_block_t root, 
}

EXPORT_SYMBOL_GPL(dm_btree_lookup);



static int dm_btree_lookup_next_single(struct dm_btree_info *info, dm_block_t root,

				       uint64_t key, uint64_t *rkey, void *value_le)

{

	int r, i;

	uint32_t flags, nr_entries;

	struct dm_block *node;

	struct btree_node *n;



	r = bn_read_lock(info, root, &node);

	if (r)

		return r;



	n = dm_block_data(node);

	flags = le32_to_cpu(n->header.flags);

	nr_entries = le32_to_cpu(n->header.nr_entries);



	if (flags & INTERNAL_NODE) {

		i = lower_bound(n, key);

		if (i < 0 || i >= nr_entries) {

			r = -ENODATA;

			goto out;

		}



		r = dm_btree_lookup_next_single(info, value64(n, i), key, rkey, value_le);

		if (r == -ENODATA && i < (nr_entries - 1)) {

			i++;

			r = dm_btree_lookup_next_single(info, value64(n, i), key, rkey, value_le);

		}



	} else {

		i = upper_bound(n, key);

		if (i < 0 || i >= nr_entries) {

			r = -ENODATA;

			goto out;

		}



		*rkey = le64_to_cpu(n->keys[i]);

		memcpy(value_le, value_ptr(n, i), info->value_type.size);

	}

out:

	dm_tm_unlock(info->tm, node);

	return r;

}



int dm_btree_lookup_next(struct dm_btree_info *info, dm_block_t root,

			 uint64_t *keys, uint64_t *rkey, void *value_le)

{

	unsigned level;

	int r = -ENODATA;

	__le64 internal_value_le;

	struct ro_spine spine;



	init_ro_spine(&spine, info);

	for (level = 0; level < info->levels - 1u; level++) {

		r = btree_lookup_raw(&spine, root, keys[level],

				     lower_bound, rkey,

				     &internal_value_le, sizeof(uint64_t));

		if (r)

			goto out;



		if (*rkey != keys[level]) {

			r = -ENODATA;

			goto out;

		}



		root = le64_to_cpu(internal_value_le);

	}



	r = dm_btree_lookup_next_single(info, root, keys[level], rkey, value_le);

out:

	exit_ro_spine(&spine);

	return r;

}



EXPORT_SYMBOL_GPL(dm_btree_lookup_next);



/*

 * Splits a node by creating a sibling node and shifting half the nodes

 * contents across.  Assumes there is a parent node, and it has room for

drivers/md/persistent-data/dm-btree.h

+11 −3
Original line number Diff line number Diff line
@@ -109,6 +109,13 @@ int dm_btree_del(struct dm_btree_info *info, dm_block_t root); 
int dm_btree_lookup(struct dm_btree_info *info, dm_block_t root,

		    uint64_t *keys, void *value_le);



/*

 * Tries to find the first key where the bottom level key is >= to that

 * given.  Useful for skipping empty sections of the btree.

 */

int dm_btree_lookup_next(struct dm_btree_info *info, dm_block_t root,

			 uint64_t *keys, uint64_t *rkey, void *value_le);



/*

 * Insertion (or overwrite an existing value).  O(ln(n))

 */
@@ -135,9 +142,10 @@ int dm_btree_remove(struct dm_btree_info *info, dm_block_t root, 
		    uint64_t *keys, dm_block_t *new_root);



/*

 * Removes values between 'keys' and keys2, where keys2 is keys with the

 * final key replaced with 'end_key'.  'end_key' is the one-past-the-end

 * value.  'keys' may be altered.

 * Removes a _contiguous_ run of values starting from 'keys' and not

 * reaching keys2 (where keys2 is keys with the final key replaced with

 * 'end_key').  'end_key' is the one-past-the-end value.  'keys' may be

 * altered.

 */

int dm_btree_remove_leaves(struct dm_btree_info *info, dm_block_t root,

			   uint64_t *keys, uint64_t end_key,