496 lines
12 KiB
C
496 lines
12 KiB
C
/*
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* Copyright (C) 2008 Red Hat. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public
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* License v2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public
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* License along with this program; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 021110-1307, USA.
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*/
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#include <linux/sched.h>
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#include "ctree.h"
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static int tree_insert_offset(struct rb_root *root, u64 offset,
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struct rb_node *node)
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{
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struct rb_node **p = &root->rb_node;
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struct rb_node *parent = NULL;
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struct btrfs_free_space *info;
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while (*p) {
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parent = *p;
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info = rb_entry(parent, struct btrfs_free_space, offset_index);
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if (offset < info->offset)
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p = &(*p)->rb_left;
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else if (offset > info->offset)
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p = &(*p)->rb_right;
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else
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return -EEXIST;
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}
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rb_link_node(node, parent, p);
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rb_insert_color(node, root);
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return 0;
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}
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static int tree_insert_bytes(struct rb_root *root, u64 bytes,
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struct rb_node *node)
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{
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struct rb_node **p = &root->rb_node;
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struct rb_node *parent = NULL;
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struct btrfs_free_space *info;
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while (*p) {
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parent = *p;
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info = rb_entry(parent, struct btrfs_free_space, bytes_index);
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if (bytes < info->bytes)
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p = &(*p)->rb_left;
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else
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p = &(*p)->rb_right;
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}
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rb_link_node(node, parent, p);
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rb_insert_color(node, root);
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return 0;
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}
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/*
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* searches the tree for the given offset. If contains is set we will return
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* the free space that contains the given offset. If contains is not set we
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* will return the free space that starts at or after the given offset and is
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* at least bytes long.
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*/
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static struct btrfs_free_space *tree_search_offset(struct rb_root *root,
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u64 offset, u64 bytes,
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int contains)
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{
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struct rb_node *n = root->rb_node;
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struct btrfs_free_space *entry, *ret = NULL;
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while (n) {
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entry = rb_entry(n, struct btrfs_free_space, offset_index);
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if (offset < entry->offset) {
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if (!contains &&
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(!ret || entry->offset < ret->offset) &&
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(bytes <= entry->bytes))
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ret = entry;
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n = n->rb_left;
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} else if (offset > entry->offset) {
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if ((entry->offset + entry->bytes - 1) >= offset &&
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bytes <= entry->bytes) {
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ret = entry;
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break;
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}
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n = n->rb_right;
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} else {
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if (bytes > entry->bytes) {
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n = n->rb_right;
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continue;
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}
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ret = entry;
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break;
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}
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}
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return ret;
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}
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/*
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* return a chunk at least bytes size, as close to offset that we can get.
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*/
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static struct btrfs_free_space *tree_search_bytes(struct rb_root *root,
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u64 offset, u64 bytes)
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{
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struct rb_node *n = root->rb_node;
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struct btrfs_free_space *entry, *ret = NULL;
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while (n) {
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entry = rb_entry(n, struct btrfs_free_space, bytes_index);
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if (bytes < entry->bytes) {
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/*
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* We prefer to get a hole size as close to the size we
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* are asking for so we don't take small slivers out of
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* huge holes, but we also want to get as close to the
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* offset as possible so we don't have a whole lot of
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* fragmentation.
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*/
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if (offset <= entry->offset) {
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if (!ret)
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ret = entry;
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else if (entry->bytes < ret->bytes)
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ret = entry;
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else if (entry->offset < ret->offset)
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ret = entry;
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}
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n = n->rb_left;
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} else if (bytes > entry->bytes) {
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n = n->rb_right;
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} else {
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/*
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* Ok we may have multiple chunks of the wanted size,
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* so we don't want to take the first one we find, we
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* want to take the one closest to our given offset, so
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* keep searching just in case theres a better match.
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*/
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n = n->rb_right;
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if (offset > entry->offset)
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continue;
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else if (!ret || entry->offset < ret->offset)
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ret = entry;
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}
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}
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return ret;
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}
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static void unlink_free_space(struct btrfs_block_group_cache *block_group,
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struct btrfs_free_space *info)
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{
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rb_erase(&info->offset_index, &block_group->free_space_offset);
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rb_erase(&info->bytes_index, &block_group->free_space_bytes);
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}
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static int link_free_space(struct btrfs_block_group_cache *block_group,
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struct btrfs_free_space *info)
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{
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int ret = 0;
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ret = tree_insert_offset(&block_group->free_space_offset, info->offset,
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&info->offset_index);
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if (ret)
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return ret;
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ret = tree_insert_bytes(&block_group->free_space_bytes, info->bytes,
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&info->bytes_index);
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if (ret)
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return ret;
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return ret;
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}
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static int __btrfs_add_free_space(struct btrfs_block_group_cache *block_group,
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u64 offset, u64 bytes)
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{
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struct btrfs_free_space *right_info;
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struct btrfs_free_space *left_info;
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struct btrfs_free_space *info = NULL;
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struct btrfs_free_space *alloc_info;
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int ret = 0;
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alloc_info = kzalloc(sizeof(struct btrfs_free_space), GFP_NOFS);
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if (!alloc_info)
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return -ENOMEM;
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/*
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* first we want to see if there is free space adjacent to the range we
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* are adding, if there is remove that struct and add a new one to
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* cover the entire range
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*/
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right_info = tree_search_offset(&block_group->free_space_offset,
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offset+bytes, 0, 1);
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left_info = tree_search_offset(&block_group->free_space_offset,
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offset-1, 0, 1);
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if (right_info && right_info->offset == offset+bytes) {
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unlink_free_space(block_group, right_info);
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info = right_info;
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info->offset = offset;
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info->bytes += bytes;
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} else if (right_info && right_info->offset != offset+bytes) {
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printk(KERN_ERR "btrfs adding space in the middle of an "
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"existing free space area. existing: "
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"offset=%llu, bytes=%llu. new: offset=%llu, "
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"bytes=%llu\n", (unsigned long long)right_info->offset,
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(unsigned long long)right_info->bytes,
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(unsigned long long)offset,
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(unsigned long long)bytes);
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BUG();
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}
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if (left_info) {
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unlink_free_space(block_group, left_info);
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if (unlikely((left_info->offset + left_info->bytes) !=
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offset)) {
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printk(KERN_ERR "btrfs free space to the left "
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"of new free space isn't "
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"quite right. existing: offset=%llu, "
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"bytes=%llu. new: offset=%llu, bytes=%llu\n",
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(unsigned long long)left_info->offset,
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(unsigned long long)left_info->bytes,
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(unsigned long long)offset,
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(unsigned long long)bytes);
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BUG();
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}
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if (info) {
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info->offset = left_info->offset;
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info->bytes += left_info->bytes;
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kfree(left_info);
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} else {
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info = left_info;
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info->bytes += bytes;
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}
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}
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if (info) {
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ret = link_free_space(block_group, info);
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if (!ret)
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info = NULL;
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goto out;
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}
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info = alloc_info;
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alloc_info = NULL;
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info->offset = offset;
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info->bytes = bytes;
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ret = link_free_space(block_group, info);
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if (ret)
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kfree(info);
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out:
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if (ret) {
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printk(KERN_ERR "btrfs: unable to add free space :%d\n", ret);
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if (ret == -EEXIST)
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BUG();
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}
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kfree(alloc_info);
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return ret;
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}
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static int
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__btrfs_remove_free_space(struct btrfs_block_group_cache *block_group,
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u64 offset, u64 bytes)
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{
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struct btrfs_free_space *info;
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int ret = 0;
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info = tree_search_offset(&block_group->free_space_offset, offset, 0,
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1);
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if (info && info->offset == offset) {
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if (info->bytes < bytes) {
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printk(KERN_ERR "Found free space at %llu, size %llu,"
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"trying to use %llu\n",
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(unsigned long long)info->offset,
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(unsigned long long)info->bytes,
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(unsigned long long)bytes);
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WARN_ON(1);
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ret = -EINVAL;
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goto out;
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}
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unlink_free_space(block_group, info);
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if (info->bytes == bytes) {
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kfree(info);
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goto out;
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}
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info->offset += bytes;
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info->bytes -= bytes;
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ret = link_free_space(block_group, info);
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BUG_ON(ret);
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} else if (info && info->offset < offset &&
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info->offset + info->bytes >= offset + bytes) {
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u64 old_start = info->offset;
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/*
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* we're freeing space in the middle of the info,
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* this can happen during tree log replay
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*
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* first unlink the old info and then
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* insert it again after the hole we're creating
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*/
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unlink_free_space(block_group, info);
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if (offset + bytes < info->offset + info->bytes) {
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u64 old_end = info->offset + info->bytes;
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info->offset = offset + bytes;
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info->bytes = old_end - info->offset;
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ret = link_free_space(block_group, info);
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BUG_ON(ret);
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} else {
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/* the hole we're creating ends at the end
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* of the info struct, just free the info
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*/
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kfree(info);
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}
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/* step two, insert a new info struct to cover anything
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* before the hole
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*/
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ret = __btrfs_add_free_space(block_group, old_start,
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offset - old_start);
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BUG_ON(ret);
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} else {
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WARN_ON(1);
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}
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out:
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return ret;
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}
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int btrfs_add_free_space(struct btrfs_block_group_cache *block_group,
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u64 offset, u64 bytes)
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{
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int ret;
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struct btrfs_free_space *sp;
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mutex_lock(&block_group->alloc_mutex);
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ret = __btrfs_add_free_space(block_group, offset, bytes);
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sp = tree_search_offset(&block_group->free_space_offset, offset, 0, 1);
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BUG_ON(!sp);
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mutex_unlock(&block_group->alloc_mutex);
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return ret;
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}
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int btrfs_add_free_space_lock(struct btrfs_block_group_cache *block_group,
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u64 offset, u64 bytes)
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{
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int ret;
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struct btrfs_free_space *sp;
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ret = __btrfs_add_free_space(block_group, offset, bytes);
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sp = tree_search_offset(&block_group->free_space_offset, offset, 0, 1);
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BUG_ON(!sp);
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return ret;
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}
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int btrfs_remove_free_space(struct btrfs_block_group_cache *block_group,
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u64 offset, u64 bytes)
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{
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int ret = 0;
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mutex_lock(&block_group->alloc_mutex);
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ret = __btrfs_remove_free_space(block_group, offset, bytes);
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mutex_unlock(&block_group->alloc_mutex);
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return ret;
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}
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int btrfs_remove_free_space_lock(struct btrfs_block_group_cache *block_group,
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u64 offset, u64 bytes)
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{
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int ret;
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ret = __btrfs_remove_free_space(block_group, offset, bytes);
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return ret;
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}
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void btrfs_dump_free_space(struct btrfs_block_group_cache *block_group,
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u64 bytes)
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{
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struct btrfs_free_space *info;
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struct rb_node *n;
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int count = 0;
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for (n = rb_first(&block_group->free_space_offset); n; n = rb_next(n)) {
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info = rb_entry(n, struct btrfs_free_space, offset_index);
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if (info->bytes >= bytes)
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count++;
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}
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printk(KERN_INFO "%d blocks of free space at or bigger than bytes is"
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"\n", count);
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}
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u64 btrfs_block_group_free_space(struct btrfs_block_group_cache *block_group)
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{
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struct btrfs_free_space *info;
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struct rb_node *n;
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u64 ret = 0;
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for (n = rb_first(&block_group->free_space_offset); n;
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n = rb_next(n)) {
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info = rb_entry(n, struct btrfs_free_space, offset_index);
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ret += info->bytes;
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}
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return ret;
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}
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void btrfs_remove_free_space_cache(struct btrfs_block_group_cache *block_group)
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{
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struct btrfs_free_space *info;
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struct rb_node *node;
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mutex_lock(&block_group->alloc_mutex);
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while ((node = rb_last(&block_group->free_space_bytes)) != NULL) {
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info = rb_entry(node, struct btrfs_free_space, bytes_index);
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unlink_free_space(block_group, info);
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kfree(info);
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if (need_resched()) {
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mutex_unlock(&block_group->alloc_mutex);
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cond_resched();
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mutex_lock(&block_group->alloc_mutex);
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}
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}
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mutex_unlock(&block_group->alloc_mutex);
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}
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#if 0
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static struct btrfs_free_space *btrfs_find_free_space_offset(struct
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btrfs_block_group_cache
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*block_group, u64 offset,
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u64 bytes)
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{
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struct btrfs_free_space *ret;
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mutex_lock(&block_group->alloc_mutex);
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ret = tree_search_offset(&block_group->free_space_offset, offset,
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bytes, 0);
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mutex_unlock(&block_group->alloc_mutex);
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return ret;
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}
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static struct btrfs_free_space *btrfs_find_free_space_bytes(struct
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btrfs_block_group_cache
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*block_group, u64 offset,
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u64 bytes)
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{
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struct btrfs_free_space *ret;
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mutex_lock(&block_group->alloc_mutex);
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ret = tree_search_bytes(&block_group->free_space_bytes, offset, bytes);
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mutex_unlock(&block_group->alloc_mutex);
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return ret;
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}
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#endif
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struct btrfs_free_space *btrfs_find_free_space(struct btrfs_block_group_cache
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*block_group, u64 offset,
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u64 bytes)
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{
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struct btrfs_free_space *ret = NULL;
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ret = tree_search_offset(&block_group->free_space_offset, offset,
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bytes, 0);
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if (!ret)
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ret = tree_search_bytes(&block_group->free_space_bytes,
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offset, bytes);
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return ret;
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}
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