Commit a6b6e75e authored by Chris Mason's avatar Chris Mason
Browse files

Btrfs: Defrag only leaves, and only when the parent node has a single objectid 



This allows us to defrag huge directories, but skip the expensive defrag
case in more common usage, where it does not help as much.

Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
parent ff79f819

fs/btrfs/ctree.c

+16 −6
Original line number Diff line number Diff line
@@ -16,6 +16,7 @@ 
 * Boston, MA 021110-1307, USA.

 */



#include <linux/sched.h>

#include "ctree.h"

#include "disk-io.h"

#include "transaction.h"
@@ -190,7 +191,8 @@ static int should_defrag_leaf(struct extent_buffer *leaf) 


int btrfs_realloc_node(struct btrfs_trans_handle *trans,

		       struct btrfs_root *root, struct extent_buffer *parent,

		       int cache_only, u64 *last_ret)

		       int start_slot, int cache_only, u64 *last_ret,

		       struct btrfs_key *progress)

{

	struct extent_buffer *cur;

	struct extent_buffer *tmp;
@@ -199,7 +201,6 @@ int btrfs_realloc_node(struct btrfs_trans_handle *trans, 
	u64 last_block = 0;

	u64 other;

	u32 parent_nritems;

	int start_slot;

	int end_slot;

	int i;

	int err = 0;
@@ -221,15 +222,24 @@ int btrfs_realloc_node(struct btrfs_trans_handle *trans, 


	parent_nritems = btrfs_header_nritems(parent);

	blocksize = btrfs_level_size(root, parent_level - 1);



	start_slot = 0;

	end_slot = parent_nritems;



	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;



		blocknr = btrfs_node_blockptr(parent, i);

		if (last_block == 0)

			last_block = blocknr;
@@ -898,7 +908,7 @@ static void reada_for_search(struct btrfs_root *root, struct btrfs_path *path, 
	u32 blocksize;

	u32 nscan = 0;



	if (level == 0)

	if (level != 1)

		return;



	if (!path->nodes[level])
@@ -2370,7 +2380,7 @@ int btrfs_del_item(struct btrfs_trans_handle *trans, struct btrfs_root *root, 
		}



		/* delete the leaf if it is mostly empty */

		if (used < BTRFS_LEAF_DATA_SIZE(root) / 3) {

		if (0 && used < BTRFS_LEAF_DATA_SIZE(root) / 3) {

			/* push_leaf_left fixes the path.

			 * make sure the path still points to our leaf

			 * for possible call to del_ptr below

fs/btrfs/ctree.h

+2 −1
Original line number Diff line number Diff line
@@ -913,7 +913,8 @@ int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root 
		      ins_len, int cow);

int btrfs_realloc_node(struct btrfs_trans_handle *trans,

		       struct btrfs_root *root, struct extent_buffer *parent,

		       int cache_only, u64 *last_ret);

		       int start_slot, int cache_only, u64 *last_ret,

		       struct btrfs_key *progress);

void btrfs_release_path(struct btrfs_root *root, struct btrfs_path *p);

struct btrfs_path *btrfs_alloc_path(void);

void btrfs_free_path(struct btrfs_path *p);

fs/btrfs/transaction.c

+0 −2
Original line number Diff line number Diff line
@@ -353,7 +353,6 @@ int btrfs_defrag_root(struct btrfs_root *root, int cacheonly) 


	if (root->defrag_running)

		return 0;



	trans = btrfs_start_transaction(root, 1);

	while (1) {

		root->defrag_running = 1;
@@ -361,7 +360,6 @@ int btrfs_defrag_root(struct btrfs_root *root, int cacheonly) 
		nr = trans->blocks_used;

		btrfs_end_transaction(trans, root);

		mutex_unlock(&info->fs_mutex);



		btrfs_btree_balance_dirty(info->tree_root, nr);

		cond_resched();

fs/btrfs/tree-defrag.c

+5 −31
Original line number Diff line number Diff line
@@ -76,7 +76,9 @@ static int defrag_walk_down(struct btrfs_trans_handle *trans, 
		if (*level == 1) {

			ret = btrfs_realloc_node(trans, root,

						 path->nodes[*level],

						 cache_only, last_ret);

						 path->slots[*level],

						 cache_only, last_ret,

						 &root->defrag_progress);

			if (is_extent)

				btrfs_extent_post_op(trans, root);
@@ -100,10 +102,6 @@ static int defrag_walk_down(struct btrfs_trans_handle *trans, 
		ret = btrfs_cow_block(trans, root, next, path->nodes[*level],

				      path->slots[*level], &next);

		BUG_ON(ret);

		ret = btrfs_realloc_node(trans, root, next, cache_only,

					 last_ret);

		BUG_ON(ret);



		if (is_extent)

			btrfs_extent_post_op(trans, root);
@@ -122,8 +120,8 @@ static int defrag_walk_down(struct btrfs_trans_handle *trans, 
	free_extent_buffer(path->nodes[*level]);

	path->nodes[*level] = NULL;

	*level += 1;

	WARN_ON(ret);

	return 0;

	WARN_ON(ret && ret != -EAGAIN);

	return ret;

}



static int defrag_walk_up(struct btrfs_trans_handle *trans,
@@ -147,27 +145,6 @@ static int defrag_walk_up(struct btrfs_trans_handle *trans, 
			root->defrag_level = i;

			return 0;

		} else {

			if (*level > 1 && path->nodes[*level] != root->node &&

			    btrfs_buffer_defrag(path->nodes[*level])) {

				struct extent_buffer *next;

				u64 last;

				int ret;

				ret = btrfs_cow_block(trans, root,

						      path->nodes[*level],

						      path->nodes[*level + 1],

						      path->slots[*level + 1],

						      &next);

				BUG_ON(ret);

				path->nodes[*level] = next;

				last = next->start;

				ret = btrfs_realloc_node(trans, root, next,

							 cache_only, &last);

				BUG_ON(ret);



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

					btrfs_extent_post_op(trans, root);

			}



			btrfs_clear_buffer_defrag(path->nodes[*level]);

			free_extent_buffer(path->nodes[*level]);

			path->nodes[*level] = NULL;
@@ -211,9 +188,6 @@ int btrfs_defrag_leaves(struct btrfs_trans_handle *trans, 
		extent_buffer_get(root->node);

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

		BUG_ON(ret);

		ret = btrfs_realloc_node(trans, root, root->node, cache_only,

					 &last_ret);

		BUG_ON(ret);

		path->nodes[level] = root->node;

		path->slots[level] = 0;

		if (is_extent)