[deliverable/linux.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) || !buffer_defrag(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);
	clear_buffer_defrag(path->nodes[*level]);
	clear_buffer_defrag_done(path->nodes[*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 {
			clear_buffer_defrag(path->nodes[*level]);
			clear_buffer_defrag_done(path->nodes[*level]);
			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) \|\|
f2183bde	89	buffer_locked(next) \|\| !buffer_defrag(next)) {
6702ed49 CM	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);
86479a04 CM	116	clear_buffer_defrag(path->nodes[*level]);
86479a04 CM	117	clear_buffer_defrag_done(path->nodes[*level]);
6702ed49 CM	118	btrfs_block_release(root, path->nodes[*level]);
	119	path->nodes[*level] = NULL;
	120	*level += 1;
	121	WARN_ON(ret);
	122	return 0;
	123	}
	124
	125	static int defrag_walk_up(struct btrfs_trans_handle *trans,
	126	struct btrfs_root *root,
	127	struct btrfs_path path, int level,
	128	int cache_only)
	129	{
	130	int i;
	131	int slot;
	132	struct btrfs_node *node;
	133
	134	for(i = *level; i < BTRFS_MAX_LEVEL - 1 && path->nodes[i]; i++) {
	135	slot = path->slots[i];
	136	if (slot < btrfs_header_nritems(
	137	btrfs_buffer_header(path->nodes[i])) - 1) {
	138	path->slots[i]++;
	139	*level = i;
	140	node = btrfs_buffer_node(path->nodes[i]);
	141	WARN_ON(i == 0);
	142	btrfs_disk_key_to_cpu(&root->defrag_progress,
	143	&node->ptrs[path->slots[i]].key);
	144	root->defrag_level = i;
	145	return 0;
	146	} else {
f2183bde	147	clear_buffer_defrag(path->nodes[*level]);
86479a04	148	clear_buffer_defrag_done(path->nodes[*level]);
6702ed49 CM	149	btrfs_block_release(root, path->nodes[*level]);
	150	path->nodes[*level] = NULL;
	151	*level = i + 1;
	152	}
	153	}
	154	return 1;
	155	}
	156
	157	int btrfs_defrag_leaves(struct btrfs_trans_handle *trans,
	158	struct btrfs_root *root, int cache_only)
	159	{
	160	struct btrfs_path *path = NULL;
	161	struct buffer_head *tmp;
	162	int ret = 0;
	163	int wret;
	164	int level;
	165	int orig_level;
	166	int i;
e9d0b13b CM	167	int is_extent = 0;
	168	u64 last_ret = 0;
	169
	170	if (root->fs_info->extent_root == root)
	171	is_extent = 1;
6702ed49	172
e9d0b13b	173	if (root->ref_cows == 0 && !is_extent)
6702ed49	174	goto out;
6702ed49 CM	175	path = btrfs_alloc_path();
	176	if (!path)
	177	return -ENOMEM;
	178
	179	level = btrfs_header_level(btrfs_buffer_header(root->node));
	180	orig_level = level;
	181	if (level == 0) {
	182	goto out;
	183	}
	184	if (root->defrag_progress.objectid == 0) {
	185	get_bh(root->node);
	186	ret = btrfs_cow_block(trans, root, root->node, NULL, 0, &tmp);
	187	BUG_ON(ret);
e9d0b13b CM	188	ret = btrfs_realloc_node(trans, root, root->node, cache_only,
e9d0b13b CM	189	&last_ret);
6702ed49 CM	190	BUG_ON(ret);
	191	path->nodes[level] = root->node;
	192	path->slots[level] = 0;
e9d0b13b CM	193	if (is_extent)
e9d0b13b CM	194	btrfs_extent_post_op(trans, root);
6702ed49 CM	195	} else {
	196	level = root->defrag_level;
	197	path->lowest_level = level;
	198	wret = btrfs_search_slot(trans, root, &root->defrag_progress,
	199	path, 0, 1);
	200
e9d0b13b CM	201	if (is_extent)
e9d0b13b CM	202	btrfs_extent_post_op(trans, root);
6702ed49 CM	203	if (wret < 0) {
	204	ret = wret;
	205	goto out;
	206	}
	207	while(level > 0 && !path->nodes[level])
	208	level--;
	209	if (!path->nodes[level]) {
	210	ret = 0;
	211	goto out;
	212	}
	213	}
	214
	215	while(1) {
e9d0b13b CM	216	wret = defrag_walk_down(trans, root, path, &level, cache_only,
e9d0b13b CM	217	&last_ret);
6702ed49 CM	218	if (wret > 0)
	219	break;
	220	if (wret < 0)
	221	ret = wret;
	222
	223	wret = defrag_walk_up(trans, root, path, &level, cache_only);
	224	if (wret > 0)
	225	break;
	226	if (wret < 0)
	227	ret = wret;
409eb95d CM	228	ret = -EAGAIN;
409eb95d CM	229	break;
6702ed49 CM	230	}
	231	for (i = 0; i <= orig_level; i++) {
	232	if (path->nodes[i]) {
	233	btrfs_block_release(root, path->nodes[i]);
	234	path->nodes[i] = 0;
	235	}
	236	}
	237	out:
	238	if (path)
	239	btrfs_free_path(path);
	240	if (ret != -EAGAIN) {
	241	memset(&root->defrag_progress, 0,
	242	sizeof(root->defrag_progress));
	243	}
	244	return ret;
	245	}