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/*
* 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)
{
struct buffer_head *next;
struct buffer_head *cur;
u64 blocknr;
int ret = 0;
WARN_ON(*level < 0);
WARN_ON(*level >= BTRFS_MAX_LEVEL);
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);
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);
BUG_ON(ret);
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 num_runs = 0;
if (root->ref_cows == 0) {
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);
BUG_ON(ret);
path->nodes[level] = root->node;
path->slots[level] = 0;
} else {
level = root->defrag_level;
path->lowest_level = level;
wret = btrfs_search_slot(trans, root, &root->defrag_progress,
path, 0, 1);
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);
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;
if (num_runs++ > 8) {
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;
}
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