Commit 5708b959 authored by Chris Mason's avatar Chris Mason
Browse files

Btrfs: Tune the automatic defrag code 



1) Forced defrag wasn't working properly (btrfsctl -d) because some
cache only checks were incorrect.

2) Defrag only the leaves unless in forced defrag mode.

3) Don't use complex logic to figure out if a leaf is needs defrag

Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
parent 18f16f7b

fs/btrfs/ctree.c

+26 −43
Original line number Diff line number Diff line
@@ -161,34 +161,6 @@ static int close_blocks(u64 blocknr, u64 other, u32 blocksize) 
	return 0;

}



static int should_defrag_leaf(struct extent_buffer *leaf)

{

	struct btrfs_key key;

	u32 nritems;



	if (btrfs_buffer_defrag(leaf))

		return 1;



	nritems = btrfs_header_nritems(leaf);

	if (nritems == 0)

		return 0;



	btrfs_item_key_to_cpu(leaf, &key, 0);

	if (key.type == BTRFS_DIR_ITEM_KEY)

		return 1;





	btrfs_item_key_to_cpu(leaf, &key, nritems - 1);

	if (key.type == BTRFS_DIR_ITEM_KEY)

		return 1;

	if (nritems > 4) {

		btrfs_item_key_to_cpu(leaf, &key, nritems / 2);

		if (key.type == BTRFS_DIR_ITEM_KEY)

			return 1;

	}

	return 0;

}



int btrfs_realloc_node(struct btrfs_trans_handle *trans,

		       struct btrfs_root *root, struct extent_buffer *parent,

		       int start_slot, int cache_only, u64 *last_ret,
@@ -208,6 +180,10 @@ int btrfs_realloc_node(struct btrfs_trans_handle *trans, 
	int uptodate;

	u32 blocksize;



	parent_level = btrfs_header_level(parent);

	if (cache_only && parent_level != 1)

		return 0;



	if (trans->transaction != root->fs_info->running_transaction) {

		printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,

		       root->fs_info->running_transaction->transid);
@@ -218,7 +194,6 @@ int btrfs_realloc_node(struct btrfs_trans_handle *trans, 
		       root->fs_info->generation);

		WARN_ON(1);

	}

	parent_level = btrfs_header_level(parent);



	parent_nritems = btrfs_header_nritems(parent);

	blocksize = btrfs_level_size(root, parent_level - 1);
@@ -227,27 +202,26 @@ int btrfs_realloc_node(struct btrfs_trans_handle *trans, 
	if (parent_nritems == 1)

		return 0;



	if (root != root->fs_info->extent_root) {

		struct btrfs_key first_key;

		struct btrfs_key last_key;



		btrfs_node_key_to_cpu(parent, &first_key, 0);

		btrfs_node_key_to_cpu(parent, &last_key, parent_nritems - 1);

		if (first_key.objectid != last_key.objectid)

			return 0;

	}



	for (i = start_slot; i < end_slot; i++) {

		int close = 1;



		if (!parent->map_token) {

			map_extent_buffer(parent,

					btrfs_node_key_ptr_offset(i),

					sizeof(struct btrfs_key_ptr),

					&parent->map_token, &parent->kaddr,

					&parent->map_start, &parent->map_len,

					KM_USER1);

		}

		blocknr = btrfs_node_blockptr(parent, i);

		if (last_block == 0)

			last_block = blocknr;



		if (i > 0) {

			other = btrfs_node_blockptr(parent, i - 1);

			close = close_blocks(blocknr, other, blocksize);

		}

		if (close && i < end_slot - 1) {

		if (close && i < end_slot - 2) {

			other = btrfs_node_blockptr(parent, i + 1);

			close = close_blocks(blocknr, other, blocksize);

		}
@@ -255,15 +229,18 @@ int btrfs_realloc_node(struct btrfs_trans_handle *trans, 
			last_block = blocknr;

			continue;

		}

		if (parent->map_token) {

			unmap_extent_buffer(parent, parent->map_token,

					    KM_USER1);

			parent->map_token = NULL;

		}



		cur = btrfs_find_tree_block(root, blocknr, blocksize);

		if (cur)

			uptodate = btrfs_buffer_uptodate(cur);

		else

			uptodate = 0;

		if (!cur || !uptodate ||

		    (parent_level != 1 && !btrfs_buffer_defrag(cur)) ||

		    (parent_level == 1 && !should_defrag_leaf(cur))) {

		if (!cur || !uptodate) {

			if (cache_only) {

				free_extent_buffer(cur);

				continue;
@@ -287,11 +264,17 @@ int btrfs_realloc_node(struct btrfs_trans_handle *trans, 
			break;

		}

		search_start = tmp->start;

		last_block = tmp->start;

		*last_ret = search_start;

		if (parent_level == 1)

			btrfs_clear_buffer_defrag(tmp);

		free_extent_buffer(tmp);

	}

	if (parent->map_token) {

		unmap_extent_buffer(parent, parent->map_token,

				    KM_USER1);

		parent->map_token = NULL;

	}

	return err;

}

fs/btrfs/tree-defrag.c

+0 −1
Original line number Diff line number Diff line
@@ -183,7 +183,6 @@ int btrfs_defrag_leaves(struct btrfs_trans_handle *trans, 
	if (level == 0) {

		goto out;

	}



	if (root->defrag_progress.objectid == 0) {

		extent_buffer_get(root->node);

		ret = btrfs_cow_block(trans, root, root->node, NULL, 0, &tmp);