[linux-2.6-block.git] / fs / btrfs / tree-defrag.c

/*
 * Copyright (C) 2007 Oracle.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License v2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 021110-1307, USA.
 */

#include <linux/sched.h>
#include "ctree.h"
#include "disk-io.h"
#include "print-tree.h"
#include "transaction.h"

static void reada_defrag(struct btrfs_root *root,
			 struct btrfs_node *node)
{
	int i;
	u32 nritems;
	u64 blocknr;
	int ret;

	nritems = btrfs_header_nritems(&node->header);
	for (i = 0; i < nritems; i++) {
		blocknr = btrfs_node_blockptr(node, i);
		ret = readahead_tree_block(root, blocknr);
		if (ret)
			break;
	}
}

static int defrag_walk_down(struct btrfs_trans_handle *trans,
			    struct btrfs_root *root,
			    struct btrfs_path *path, int *level,
			    int cache_only, u64 *last_ret)
{
	struct buffer_head *next;
	struct buffer_head *cur;
	u64 blocknr;
	int ret = 0;
	int is_extent = 0;

	WARN_ON(*level < 0);
	WARN_ON(*level >= BTRFS_MAX_LEVEL);

	if (root->fs_info->extent_root == root)
		is_extent = 1;

	while(*level > 0) {
		WARN_ON(*level < 0);
		WARN_ON(*level >= BTRFS_MAX_LEVEL);
		cur = path->nodes[*level];

		if (!cache_only && *level > 1 && path->slots[*level] == 0)
			reada_defrag(root, btrfs_buffer_node(cur));

		if (btrfs_header_level(btrfs_buffer_header(cur)) != *level)
			WARN_ON(1);

		if (path->slots[*level] >=
		    btrfs_header_nritems(btrfs_buffer_header(cur)))
			break;

		if (*level == 1) {
			ret = btrfs_realloc_node(trans, root,
						 path->nodes[*level],
						 cache_only, last_ret);
			if (is_extent)
				btrfs_extent_post_op(trans, root);

			break;
		}
		blocknr = btrfs_node_blockptr(btrfs_buffer_node(cur),
					      path->slots[*level]);

		if (cache_only) {
			next = btrfs_find_tree_block(root, blocknr);
			if (!next || !buffer_uptodate(next) ||
			   buffer_locked(next)) {
				brelse(next);
				path->slots[*level]++;
				continue;
			}
		} else {
			next = read_tree_block(root, blocknr);
		}
		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);

		WARN_ON(*level <= 0);
		if (path->nodes[*level-1])
			btrfs_block_release(root, path->nodes[*level-1]);
		path->nodes[*level-1] = next;
		*level = btrfs_header_level(btrfs_buffer_header(next));
		path->slots[*level] = 0;
	}
	WARN_ON(*level < 0);
	WARN_ON(*level >= BTRFS_MAX_LEVEL);
	btrfs_block_release(root, path->nodes[*level]);
	path->nodes[*level] = NULL;
	*level += 1;
	WARN_ON(ret);
	return 0;
}

static int defrag_walk_up(struct btrfs_trans_handle *trans,
			  struct btrfs_root *root,
			  struct btrfs_path *path, int *level,
			  int cache_only)
{
	int i;
	int slot;
	struct btrfs_node *node;

	for(i = *level; i < BTRFS_MAX_LEVEL - 1 && path->nodes[i]; i++) {
		slot = path->slots[i];
		if (slot < btrfs_header_nritems(
		    btrfs_buffer_header(path->nodes[i])) - 1) {
			path->slots[i]++;
			*level = i;
			node = btrfs_buffer_node(path->nodes[i]);
			WARN_ON(i == 0);
			btrfs_disk_key_to_cpu(&root->defrag_progress,
					      &node->ptrs[path->slots[i]].key);
			root->defrag_level = i;
			return 0;
		} else {
			btrfs_block_release(root, path->nodes[*level]);
			path->nodes[*level] = NULL;
			*level = i + 1;
		}
	}
	return 1;
}

int btrfs_defrag_leaves(struct btrfs_trans_handle *trans,
			struct btrfs_root *root, int cache_only)
{
	struct btrfs_path *path = NULL;
	struct buffer_head *tmp;
	int ret = 0;
	int wret;
	int level;
	int orig_level;
	int i;
	int is_extent = 0;
	u64 last_ret = 0;

	if (root->fs_info->extent_root == root)
		is_extent = 1;

	if (root->ref_cows == 0 && !is_extent)
		goto out;
	path = btrfs_alloc_path();
	if (!path)
		return -ENOMEM;

	level = btrfs_header_level(btrfs_buffer_header(root->node));
	orig_level = level;
	if (level == 0) {
		goto out;
	}
	if (root->defrag_progress.objectid == 0) {
		get_bh(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)
			btrfs_extent_post_op(trans, root);
	} else {
		level = root->defrag_level;
		path->lowest_level = level;
		wret = btrfs_search_slot(trans, root, &root->defrag_progress,
					 path, 0, 1);

		if (is_extent)
			btrfs_extent_post_op(trans, root);
		if (wret < 0) {
			ret = wret;
			goto out;
		}
		while(level > 0 && !path->nodes[level])
			level--;
		if (!path->nodes[level]) {
			ret = 0;
			goto out;
		}
	}

	while(1) {
		wret = defrag_walk_down(trans, root, path, &level, cache_only,
					&last_ret);
		if (wret > 0)
			break;
		if (wret < 0)
			ret = wret;

		wret = defrag_walk_up(trans, root, path, &level, cache_only);
		if (wret > 0)
			break;
		if (wret < 0)
			ret = wret;
		ret = -EAGAIN;
		break;
	}
	for (i = 0; i <= orig_level; i++) {
		if (path->nodes[i]) {
			btrfs_block_release(root, path->nodes[i]);
			path->nodes[i] = 0;
		}
	}
out:
	if (path)
		btrfs_free_path(path);
	if (ret != -EAGAIN) {
		memset(&root->defrag_progress, 0,
		       sizeof(root->defrag_progress));
	}
	return ret;
}
Commit	Line	Data
6702ed49 CM	1	/*
	2	* Copyright (C) 2007 Oracle. All rights reserved.
	3	*
	4	* This program is free software; you can redistribute it and/or
	5	* modify it under the terms of the GNU General Public
	6	* License v2 as published by the Free Software Foundation.
	7	*
	8	* This program is distributed in the hope that it will be useful,
	9	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	10	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	11	* General Public License for more details.
	12	*
	13	* You should have received a copy of the GNU General Public
	14	* License along with this program; if not, write to the
	15	* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
	16	* Boston, MA 021110-1307, USA.
	17	*/
	18
	19	#include <linux/sched.h>
	20	#include "ctree.h"
	21	#include "disk-io.h"
	22	#include "print-tree.h"
	23	#include "transaction.h"
	24
	25	static void reada_defrag(struct btrfs_root *root,
	26	struct btrfs_node *node)
	27	{
	28	int i;
	29	u32 nritems;
	30	u64 blocknr;
	31	int ret;
	32
	33	nritems = btrfs_header_nritems(&node->header);
	34	for (i = 0; i < nritems; i++) {
	35	blocknr = btrfs_node_blockptr(node, i);
	36	ret = readahead_tree_block(root, blocknr);
	37	if (ret)
	38	break;
	39	}
	40	}
	41
	42	static int defrag_walk_down(struct btrfs_trans_handle *trans,
	43	struct btrfs_root *root,
	44	struct btrfs_path path, int level,
e9d0b13b	45	int cache_only, u64 *last_ret)
6702ed49 CM	46	{
	47	struct buffer_head *next;
	48	struct buffer_head *cur;
	49	u64 blocknr;
	50	int ret = 0;
e9d0b13b	51	int is_extent = 0;
6702ed49 CM	52
	53	WARN_ON(*level < 0);
	54	WARN_ON(*level >= BTRFS_MAX_LEVEL);
	55
e9d0b13b CM	56	if (root->fs_info->extent_root == root)
	57	is_extent = 1;
	58
6702ed49 CM	59	while(*level > 0) {
	60	WARN_ON(*level < 0);
	61	WARN_ON(*level >= BTRFS_MAX_LEVEL);
	62	cur = path->nodes[*level];
	63
	64	if (!cache_only && level > 1 && path->slots[level] == 0)
	65	reada_defrag(root, btrfs_buffer_node(cur));
	66
	67	if (btrfs_header_level(btrfs_buffer_header(cur)) != *level)
	68	WARN_ON(1);
	69
	70	if (path->slots[*level] >=
	71	btrfs_header_nritems(btrfs_buffer_header(cur)))
	72	break;
	73
	74	if (*level == 1) {
	75	ret = btrfs_realloc_node(trans, root,
	76	path->nodes[*level],
e9d0b13b CM	77	cache_only, last_ret);
	78	if (is_extent)
	79	btrfs_extent_post_op(trans, root);
	80
6702ed49 CM	81	break;
	82	}
	83	blocknr = btrfs_node_blockptr(btrfs_buffer_node(cur),
	84	path->slots[*level]);
	85
	86	if (cache_only) {
	87	next = btrfs_find_tree_block(root, blocknr);
	88	if (!next \|\| !buffer_uptodate(next) \|\|
	89	buffer_locked(next)) {
	90	brelse(next);
	91	path->slots[*level]++;
	92	continue;
	93	}
	94	} else {
	95	next = read_tree_block(root, blocknr);
	96	}
	97	ret = btrfs_cow_block(trans, root, next, path->nodes[*level],
	98	path->slots[*level], &next);
	99	BUG_ON(ret);
e9d0b13b CM	100	ret = btrfs_realloc_node(trans, root, next, cache_only,
e9d0b13b CM	101	last_ret);
6702ed49	102	BUG_ON(ret);
e9d0b13b CM	103
	104	if (is_extent)
	105	btrfs_extent_post_op(trans, root);
	106
6702ed49 CM	107	WARN_ON(*level <= 0);
	108	if (path->nodes[*level-1])
	109	btrfs_block_release(root, path->nodes[*level-1]);
	110	path->nodes[*level-1] = next;
	111	*level = btrfs_header_level(btrfs_buffer_header(next));
	112	path->slots[*level] = 0;
	113	}
	114	WARN_ON(*level < 0);
	115	WARN_ON(*level >= BTRFS_MAX_LEVEL);
	116	btrfs_block_release(root, path->nodes[*level]);
	117	path->nodes[*level] = NULL;
	118	*level += 1;
	119	WARN_ON(ret);
	120	return 0;
	121	}
	122
	123	static int defrag_walk_up(struct btrfs_trans_handle *trans,
	124	struct btrfs_root *root,
	125	struct btrfs_path path, int level,
	126	int cache_only)
	127	{
	128	int i;
	129	int slot;
	130	struct btrfs_node *node;
	131
	132	for(i = *level; i < BTRFS_MAX_LEVEL - 1 && path->nodes[i]; i++) {
	133	slot = path->slots[i];
	134	if (slot < btrfs_header_nritems(
	135	btrfs_buffer_header(path->nodes[i])) - 1) {
	136	path->slots[i]++;
	137	*level = i;
	138	node = btrfs_buffer_node(path->nodes[i]);
	139	WARN_ON(i == 0);
	140	btrfs_disk_key_to_cpu(&root->defrag_progress,
	141	&node->ptrs[path->slots[i]].key);
	142	root->defrag_level = i;
	143	return 0;
	144	} else {
	145	btrfs_block_release(root, path->nodes[*level]);
	146	path->nodes[*level] = NULL;
	147	*level = i + 1;
	148	}
	149	}
	150	return 1;
	151	}
	152
	153	int btrfs_defrag_leaves(struct btrfs_trans_handle *trans,
	154	struct btrfs_root *root, int cache_only)
	155	{
	156	struct btrfs_path *path = NULL;
	157	struct buffer_head *tmp;
	158	int ret = 0;
	159	int wret;
	160	int level;
	161	int orig_level;
	162	int i;
e9d0b13b CM	163	int is_extent = 0;
	164	u64 last_ret = 0;
	165
	166	if (root->fs_info->extent_root == root)
	167	is_extent = 1;
6702ed49	168
e9d0b13b	169	if (root->ref_cows == 0 && !is_extent)
6702ed49	170	goto out;
6702ed49 CM	171	path = btrfs_alloc_path();
	172	if (!path)
	173	return -ENOMEM;
	174
	175	level = btrfs_header_level(btrfs_buffer_header(root->node));
	176	orig_level = level;
	177	if (level == 0) {
	178	goto out;
	179	}
	180	if (root->defrag_progress.objectid == 0) {
	181	get_bh(root->node);
	182	ret = btrfs_cow_block(trans, root, root->node, NULL, 0, &tmp);
	183	BUG_ON(ret);
e9d0b13b CM	184	ret = btrfs_realloc_node(trans, root, root->node, cache_only,
e9d0b13b CM	185	&last_ret);
6702ed49 CM	186	BUG_ON(ret);
	187	path->nodes[level] = root->node;
	188	path->slots[level] = 0;
e9d0b13b CM	189	if (is_extent)
e9d0b13b CM	190	btrfs_extent_post_op(trans, root);
6702ed49 CM	191	} else {
	192	level = root->defrag_level;
	193	path->lowest_level = level;
	194	wret = btrfs_search_slot(trans, root, &root->defrag_progress,
	195	path, 0, 1);
	196
e9d0b13b CM	197	if (is_extent)
e9d0b13b CM	198	btrfs_extent_post_op(trans, root);
6702ed49 CM	199	if (wret < 0) {
	200	ret = wret;
	201	goto out;
	202	}
	203	while(level > 0 && !path->nodes[level])
	204	level--;
	205	if (!path->nodes[level]) {
	206	ret = 0;
	207	goto out;
	208	}
	209	}
	210
	211	while(1) {
e9d0b13b CM	212	wret = defrag_walk_down(trans, root, path, &level, cache_only,
e9d0b13b CM	213	&last_ret);
6702ed49 CM	214	if (wret > 0)
	215	break;
	216	if (wret < 0)
	217	ret = wret;
	218
	219	wret = defrag_walk_up(trans, root, path, &level, cache_only);
	220	if (wret > 0)
	221	break;
	222	if (wret < 0)
	223	ret = wret;
409eb95d CM	224	ret = -EAGAIN;
409eb95d CM	225	break;
6702ed49 CM	226	}
	227	for (i = 0; i <= orig_level; i++) {
	228	if (path->nodes[i]) {
	229	btrfs_block_release(root, path->nodes[i]);
	230	path->nodes[i] = 0;
	231	}
	232	}
	233	out:
	234	if (path)
	235	btrfs_free_path(path);
	236	if (ret != -EAGAIN) {
	237	memset(&root->defrag_progress, 0,
	238	sizeof(root->defrag_progress));
	239	}
	240	return ret;
	241	}