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Commit 73e48b27 authored by Yan's avatar Yan Committed by Chris Mason
Browse files

Btrfs: Properly handle overlapping extent in shrink_extent_tree 



The patch fixes the overlapping extent issue in shrink_extent_tree.
It checks whether there is an overlapping extent by using
find_previous_extent. If there is an overlapping extent, it setups
key.objectid and cur_byte properly.

---

Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
parent d548ee51

fs/btrfs/extent-tree.c

+56 −84
Original line number Diff line number Diff line
@@ -2317,36 +2317,6 @@ static int noinline relocate_one_extent(struct btrfs_root *extent_root, 
	return ret;

}



static int find_overlapping_extent(struct btrfs_root *root,

				   struct btrfs_path *path, u64 new_size)

{

	struct btrfs_key found_key;

	struct extent_buffer *leaf;

	int ret;



	while(1) {

		if (path->slots[0] == 0) {

			ret = btrfs_prev_leaf(root, path);

			if (ret == 1) {

				return 1;

			}

			if (ret < 0)

				return ret;

		} else {

			path->slots[0]--;

		}

		leaf = path->nodes[0];

		btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);

		if (found_key.type == BTRFS_EXTENT_ITEM_KEY) {

			if (found_key.objectid + found_key.offset > new_size)

				return 0;

			else

				return 1;

		}

	}

	return 1;

}



int btrfs_shrink_extent_tree(struct btrfs_root *root, u64 new_size)

{

	struct btrfs_trans_handle *trans;
@@ -2357,11 +2327,10 @@ int btrfs_shrink_extent_tree(struct btrfs_root *root, u64 new_size) 
	struct btrfs_fs_info *info = root->fs_info;

	struct extent_map_tree *block_group_cache;

	struct btrfs_key key;

	struct btrfs_key found_key = { 0, 0, 0 };

	struct btrfs_key found_key;

	struct extent_buffer *leaf;

	u32 nritems;

	int ret;

	int slot;



	btrfs_set_super_total_bytes(&info->super_copy, new_size);

	block_group_cache = &info->block_group_cache;
@@ -2372,34 +2341,35 @@ int btrfs_shrink_extent_tree(struct btrfs_root *root, u64 new_size) 
again:

	total_found = 0;

	key.objectid = new_size;

	cur_byte = key.objectid;

	key.offset = 0;

	key.type = 0;

	while(1) {

	cur_byte = key.objectid;



	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);

	if (ret < 0)

		goto out;

next:

		leaf = path->nodes[0];

		if (key.objectid == new_size - 1) {

			ret = find_overlapping_extent(root, path, new_size);

			if (ret != 0) {

				btrfs_release_path(root, path);

				ret = btrfs_search_slot(NULL, root, &key,

							path, 0, 0);



	ret = find_previous_extent(root, path);

	if (ret < 0)

		goto out;

	if (ret == 0) {

		leaf = path->nodes[0];

		btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);

		if (found_key.objectid + found_key.offset > new_size) {

			cur_byte = found_key.objectid;

			key.objectid = cur_byte;

		}

	}

	btrfs_release_path(root, path);



	while(1) {

		ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);

		if (ret < 0)

			goto out;



		leaf = path->nodes[0];

		nritems = btrfs_header_nritems(leaf);

		ret = 0;

		slot = path->slots[0];

		if (slot < nritems)

			btrfs_item_key_to_cpu(leaf, &found_key, slot);

		if (slot == nritems ||

		    btrfs_key_type(&found_key) != BTRFS_EXTENT_ITEM_KEY) {

			path->slots[0]++;

next:

		if (path->slots[0] >= nritems) {

			ret = btrfs_next_leaf(root, path);

			if (ret < 0)
@@ -2408,12 +2378,17 @@ int btrfs_shrink_extent_tree(struct btrfs_root *root, u64 new_size) 
				ret = 0;

				break;

			}

			leaf = path->nodes[0];

			nritems = btrfs_header_nritems(leaf);

		}



		btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);

		if (btrfs_key_type(&found_key) != BTRFS_EXTENT_ITEM_KEY ||

		    found_key.objectid + found_key.offset <= cur_byte) {

			path->slots[0]++;

			goto next;

		}

		btrfs_item_key_to_cpu(leaf, &found_key, slot);

		if (found_key.objectid + found_key.offset <= cur_byte)

			continue;



		total_found++;

		cur_byte = found_key.objectid + found_key.offset;

		key.objectid = cur_byte;
@@ -2446,21 +2421,10 @@ int btrfs_shrink_extent_tree(struct btrfs_root *root, u64 new_size) 
		ret = btrfs_search_slot(trans, root, &key, path, -1, 1);

		if (ret < 0)

			goto out;

bg_next:



		leaf = path->nodes[0];

		nritems = btrfs_header_nritems(leaf);

		ret = 0;

		slot = path->slots[0];

		if (slot < nritems)

			btrfs_item_key_to_cpu(leaf, &found_key, slot);

		if (slot == nritems ||

		    btrfs_key_type(&found_key) != BTRFS_BLOCK_GROUP_ITEM_KEY) {

			if (slot < nritems) {

				printk("shrinker found key %Lu %u %Lu\n",

				       found_key.objectid, found_key.type,

				       found_key.offset);

				path->slots[0]++;

			}

bg_next:

		if (path->slots[0] >= nritems) {

			ret = btrfs_next_leaf(root, path);

			if (ret < 0)
@@ -2469,10 +2433,18 @@ int btrfs_shrink_extent_tree(struct btrfs_root *root, u64 new_size) 
				ret = 0;

				break;

			}

			leaf = path->nodes[0];

			nritems = btrfs_header_nritems(leaf);

		}



		btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);

		if (btrfs_key_type(&found_key) != BTRFS_BLOCK_GROUP_ITEM_KEY) {

			printk("shrinker found key %Lu %u %Lu\n",

				found_key.objectid, found_key.type,

				found_key.offset);

			path->slots[0]++;

			goto bg_next;

		}

		btrfs_item_key_to_cpu(leaf, &found_key, slot);

		ret = get_state_private(&info->block_group_cache,

					found_key.objectid, &ptr);

		if (!ret)