linux/fs/btrfs/extent-tree.c

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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"
#define BLOCK_GROUP_DATA EXTENT_WRITEBACK
#define BLOCK_GROUP_METADATA EXTENT_UPTODATE
#define BLOCK_GROUP_DIRTY EXTENT_DIRTY
static int finish_current_insert(struct btrfs_trans_handle *trans, struct
btrfs_root *extent_root);
static int del_pending_extents(struct btrfs_trans_handle *trans, struct
btrfs_root *extent_root);
static int cache_block_group(struct btrfs_root *root,
struct btrfs_block_group_cache *block_group)
{
struct btrfs_path *path;
int ret;
struct btrfs_key key;
struct extent_buffer *leaf;
struct extent_map_tree *free_space_cache;
int slot;
u64 last = 0;
u64 hole_size;
u64 first_free;
int found = 0;
root = root->fs_info->extent_root;
free_space_cache = &root->fs_info->free_space_cache;
if (block_group->cached)
return 0;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
path->reada = 2;
first_free = block_group->key.objectid;
key.objectid = block_group->key.objectid;
key.offset = 0;
btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
if (ret < 0)
return ret;
if (ret && path->slots[0] > 0)
path->slots[0]--;
while(1) {
leaf = path->nodes[0];
slot = path->slots[0];
if (slot >= btrfs_header_nritems(leaf)) {
ret = btrfs_next_leaf(root, path);
if (ret < 0)
goto err;
if (ret == 0) {
continue;
} else {
break;
}
}
btrfs_item_key_to_cpu(leaf, &key, slot);
if (key.objectid < block_group->key.objectid) {
if (key.objectid + key.offset > first_free)
first_free = key.objectid + key.offset;
goto next;
}
if (key.objectid >= block_group->key.objectid +
block_group->key.offset) {
break;
}
if (btrfs_key_type(&key) == BTRFS_EXTENT_ITEM_KEY) {
if (!found) {
last = first_free;
found = 1;
}
if (key.objectid > last) {
hole_size = key.objectid - last;
set_extent_dirty(free_space_cache, last,
last + hole_size - 1,
GFP_NOFS);
}
last = key.objectid + key.offset;
}
next:
path->slots[0]++;
}
if (!found)
last = first_free;
if (block_group->key.objectid +
block_group->key.offset > last) {
hole_size = block_group->key.objectid +
block_group->key.offset - last;
set_extent_dirty(free_space_cache, last,
last + hole_size - 1, GFP_NOFS);
}
block_group->cached = 1;
err:
btrfs_free_path(path);
return 0;
}
struct btrfs_block_group_cache *btrfs_lookup_block_group(struct
btrfs_fs_info *info,
u64 blocknr)
{
struct extent_map_tree *block_group_cache;
struct btrfs_block_group_cache *block_group = NULL;
u64 ptr;
u64 start;
u64 end;
int ret;
block_group_cache = &info->block_group_cache;
ret = find_first_extent_bit(block_group_cache,
blocknr, &start, &end,
BLOCK_GROUP_DATA | BLOCK_GROUP_METADATA);
if (ret) {
return NULL;
}
ret = get_state_private(block_group_cache, start, &ptr);
if (ret)
return NULL;
block_group = (struct btrfs_block_group_cache *)ptr;
if (block_group->key.objectid <= blocknr && blocknr <=
block_group->key.objectid + block_group->key.offset)
return block_group;
return NULL;
}
static u64 find_search_start(struct btrfs_root *root,
struct btrfs_block_group_cache **cache_ret,
u64 search_start, int num, int data)
{
int ret;
struct btrfs_block_group_cache *cache = *cache_ret;
u64 last = max(search_start, cache->key.objectid);
u64 start = 0;
u64 end = 0;
again:
ret = cache_block_group(root, cache);
if (ret)
goto out;
while(1) {
ret = find_first_extent_bit(&root->fs_info->free_space_cache,
last, &start, &end, EXTENT_DIRTY);
if (ret)
goto out;
start = max(last, start);
last = end + 1;
if (end + 1 - start < num)
continue;
if (start + num >= cache->key.objectid + cache->key.offset)
goto new_group;
return start;
}
out:
return search_start;
new_group:
cache = btrfs_lookup_block_group(root->fs_info,
last + cache->key.offset - 1);
if (!cache) {
return search_start;
}
cache = btrfs_find_block_group(root, cache,
last + cache->key.offset - 1, data, 0);
*cache_ret = cache;
last = min(cache->key.objectid, last);
goto again;
}
static u64 div_factor(u64 num, int factor)
{
num *= factor;
do_div(num, 10);
return num;
}
struct btrfs_block_group_cache *btrfs_find_block_group(struct btrfs_root *root,
struct btrfs_block_group_cache
*hint, u64 search_start,
int data, int owner)
{
struct btrfs_block_group_cache *cache;
struct extent_map_tree *block_group_cache;
struct btrfs_block_group_cache *found_group = NULL;
struct btrfs_fs_info *info = root->fs_info;
u64 used;
u64 last = 0;
u64 hint_last;
u64 start;
u64 end;
u64 free_check;
u64 ptr;
int bit;
int ret;
int full_search = 0;
int factor = 8;
int data_swap = 0;
block_group_cache = &info->block_group_cache;
if (!owner)
factor = 5;
if (data)
bit = BLOCK_GROUP_DATA;
else
bit = BLOCK_GROUP_METADATA;
if (search_start) {
struct btrfs_block_group_cache *shint;
shint = btrfs_lookup_block_group(info, search_start);
if (shint && shint->data == data) {
used = btrfs_block_group_used(&shint->item);
if (used < div_factor(shint->key.offset, factor)) {
return shint;
}
}
}
if (hint && hint->data == data) {
used = btrfs_block_group_used(&hint->item);
if (used < div_factor(hint->key.offset, factor)) {
return hint;
}
last = hint->key.offset * 3;
if (hint->key.objectid >= last)
last = max(search_start + hint->key.offset - 1,
hint->key.objectid - last);
else
last = hint->key.objectid + hint->key.offset;
hint_last = last;
} else {
if (hint)
hint_last = max(hint->key.objectid, search_start);
else
hint_last = search_start;
last = hint_last;
}
again:
while(1) {
ret = find_first_extent_bit(block_group_cache, last,
&start, &end, bit);
if (ret)
break;
ret = get_state_private(block_group_cache, start, &ptr);
if (ret)
break;
cache = (struct btrfs_block_group_cache *)ptr;
last = cache->key.objectid + cache->key.offset;
used = btrfs_block_group_used(&cache->item);
if (full_search)
free_check = cache->key.offset;
else
free_check = div_factor(cache->key.offset, factor);
if (used < free_check) {
found_group = cache;
goto found;
}
cond_resched();
}
if (!full_search) {
last = search_start;
full_search = 1;
goto again;
}
if (!data_swap) {
data_swap = 1;
bit = BLOCK_GROUP_DATA | BLOCK_GROUP_METADATA;
last = search_start;
goto again;
}
found:
return found_group;
}
int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
u64 blocknr, u64 num_blocks)
{
struct btrfs_path *path;
int ret;
struct btrfs_key key;
struct extent_buffer *l;
struct btrfs_extent_item *item;
u32 refs;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
key.objectid = blocknr;
btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
key.offset = num_blocks;
ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
0, 1);
if (ret < 0)
return ret;
if (ret != 0) {
BUG();
}
BUG_ON(ret != 0);
l = path->nodes[0];
item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
refs = btrfs_extent_refs(l, item);
btrfs_set_extent_refs(l, item, refs + 1);
btrfs_mark_buffer_dirty(path->nodes[0]);
btrfs_release_path(root->fs_info->extent_root, path);
btrfs_free_path(path);
finish_current_insert(trans, root->fs_info->extent_root);
del_pending_extents(trans, root->fs_info->extent_root);
return 0;
}
int btrfs_extent_post_op(struct btrfs_trans_handle *trans,
struct btrfs_root *root)
{
finish_current_insert(trans, root->fs_info->extent_root);
del_pending_extents(trans, root->fs_info->extent_root);
return 0;
}
static int lookup_extent_ref(struct btrfs_trans_handle *trans,
struct btrfs_root *root, u64 blocknr,
u64 num_blocks, u32 *refs)
{
struct btrfs_path *path;
int ret;
struct btrfs_key key;
struct extent_buffer *l;
struct btrfs_extent_item *item;
path = btrfs_alloc_path();
key.objectid = blocknr;
key.offset = num_blocks;
btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
0, 0);
if (ret < 0)
goto out;
if (ret != 0) {
btrfs_print_leaf(root, path->nodes[0]);
printk("failed to find block number %Lu\n", blocknr);
BUG();
}
l = path->nodes[0];
item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
*refs = btrfs_extent_refs(l, item);
out:
btrfs_free_path(path);
return 0;
}
int btrfs_inc_root_ref(struct btrfs_trans_handle *trans,
struct btrfs_root *root)
{
return btrfs_inc_extent_ref(trans, root,
extent_buffer_blocknr(root->node), 1);
}
int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
struct extent_buffer *buf)
{
u64 blocknr;
u32 nritems;
struct btrfs_key key;
struct btrfs_file_extent_item *fi;
int i;
int leaf;
int ret;
int faili;
int err;
if (!root->ref_cows)
return 0;
leaf = btrfs_is_leaf(buf);
nritems = btrfs_header_nritems(buf);
for (i = 0; i < nritems; i++) {
if (leaf) {
u64 disk_blocknr;
btrfs_item_key_to_cpu(buf, &key, i);
if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
continue;
fi = btrfs_item_ptr(buf, i,
struct btrfs_file_extent_item);
if (btrfs_file_extent_type(buf, fi) ==
BTRFS_FILE_EXTENT_INLINE)
continue;
disk_blocknr = btrfs_file_extent_disk_blocknr(buf, fi);
if (disk_blocknr == 0)
continue;
ret = btrfs_inc_extent_ref(trans, root, disk_blocknr,
btrfs_file_extent_disk_num_blocks(buf, fi));
if (ret) {
faili = i;
goto fail;
}
} else {
blocknr = btrfs_node_blockptr(buf, i);
ret = btrfs_inc_extent_ref(trans, root, blocknr, 1);
if (ret) {
faili = i;
goto fail;
}
}
}
return 0;
fail:
WARN_ON(1);
for (i =0; i < faili; i++) {
if (leaf) {
u64 disk_blocknr;
btrfs_item_key_to_cpu(buf, &key, i);
if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
continue;
fi = btrfs_item_ptr(buf, i,
struct btrfs_file_extent_item);
if (btrfs_file_extent_type(buf, fi) ==
BTRFS_FILE_EXTENT_INLINE)
continue;
disk_blocknr = btrfs_file_extent_disk_blocknr(buf, fi);
if (disk_blocknr == 0)
continue;
err = btrfs_free_extent(trans, root, disk_blocknr,
btrfs_file_extent_disk_num_blocks(buf,
fi), 0);
BUG_ON(err);
} else {
blocknr = btrfs_node_blockptr(buf, i);
err = btrfs_free_extent(trans, root, blocknr, 1, 0);
BUG_ON(err);
}
}
return ret;
}
static int write_one_cache_group(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path,
struct btrfs_block_group_cache *cache)
{
int ret;
int pending_ret;
struct btrfs_root *extent_root = root->fs_info->extent_root;
unsigned long bi;
struct extent_buffer *leaf;
ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
if (ret < 0)
goto fail;
BUG_ON(ret);
leaf = path->nodes[0];
bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
btrfs_mark_buffer_dirty(leaf);
btrfs_release_path(extent_root, path);
fail:
finish_current_insert(trans, extent_root);
pending_ret = del_pending_extents(trans, extent_root);
if (ret)
return ret;
if (pending_ret)
return pending_ret;
return 0;
}
int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
struct btrfs_root *root)
{
struct extent_map_tree *block_group_cache;
struct btrfs_block_group_cache *cache;
int ret;
int err = 0;
int werr = 0;
struct btrfs_path *path;
u64 last = 0;
u64 start;
u64 end;
u64 ptr;
block_group_cache = &root->fs_info->block_group_cache;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
while(1) {
ret = find_first_extent_bit(block_group_cache, last,
&start, &end, BLOCK_GROUP_DIRTY);
if (ret)
break;
last = end + 1;
ret = get_state_private(block_group_cache, start, &ptr);
if (ret)
break;
cache = (struct btrfs_block_group_cache *)ptr;
err = write_one_cache_group(trans, root,
path, cache);
/*
* if we fail to write the cache group, we want
* to keep it marked dirty in hopes that a later
* write will work
*/
if (err) {
werr = err;
continue;
}
clear_extent_bits(block_group_cache, start, end,
BLOCK_GROUP_DIRTY, GFP_NOFS);
}
btrfs_free_path(path);
return werr;
}
static int update_block_group(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
u64 blocknr, u64 num, int alloc, int mark_free,
int data)
{
struct btrfs_block_group_cache *cache;
struct btrfs_fs_info *info = root->fs_info;
u64 total = num;
u64 old_val;
u64 block_in_group;
u64 start;
u64 end;
while(total) {
cache = btrfs_lookup_block_group(info, blocknr);
if (!cache) {
return -1;
}
block_in_group = blocknr - cache->key.objectid;
WARN_ON(block_in_group > cache->key.offset);
start = cache->key.objectid;
end = start + cache->key.offset - 1;
set_extent_bits(&info->block_group_cache, start, end,
BLOCK_GROUP_DIRTY, GFP_NOFS);
old_val = btrfs_block_group_used(&cache->item);
num = min(total, cache->key.offset - block_in_group);
if (alloc) {
if (cache->data != data &&
old_val < (cache->key.offset >> 1)) {
int bit_to_clear;
int bit_to_set;
cache->data = data;
if (data) {
bit_to_clear = BLOCK_GROUP_DATA;
bit_to_set = BLOCK_GROUP_METADATA;
cache->item.flags |=
BTRFS_BLOCK_GROUP_DATA;
} else {
bit_to_clear = BLOCK_GROUP_METADATA;
bit_to_set = BLOCK_GROUP_DATA;
cache->item.flags &=
~BTRFS_BLOCK_GROUP_DATA;
}
clear_extent_bits(&info->block_group_cache,
start, end, bit_to_clear,
GFP_NOFS);
set_extent_bits(&info->block_group_cache,
start, end, bit_to_set,
GFP_NOFS);
}
old_val += num;
} else {
old_val -= num;
if (mark_free) {
set_extent_dirty(&info->free_space_cache,
blocknr, blocknr + num - 1,
GFP_NOFS);
}
}
btrfs_set_block_group_used(&cache->item, old_val);
total -= num;
blocknr += num;
}
return 0;
}
int btrfs_copy_pinned(struct btrfs_root *root, struct extent_map_tree *copy)
{
u64 last = 0;
u64 start;
u64 end;
struct extent_map_tree *pinned_extents = &root->fs_info->pinned_extents;
int ret;
while(1) {
ret = find_first_extent_bit(pinned_extents, last,
&start, &end, EXTENT_DIRTY);
if (ret)
break;
set_extent_dirty(copy, start, end, GFP_NOFS);
last = end + 1;
}
return 0;
}
int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct extent_map_tree *unpin)
{
u64 start;
u64 end;
int ret;
struct extent_map_tree *pinned_extents = &root->fs_info->pinned_extents;
struct extent_map_tree *free_space_cache;
free_space_cache = &root->fs_info->free_space_cache;
while(1) {
ret = find_first_extent_bit(unpin, 0, &start, &end,
EXTENT_DIRTY);
if (ret)
break;
clear_extent_dirty(pinned_extents, start, end,
GFP_NOFS);
clear_extent_dirty(unpin, start, end, GFP_NOFS);
set_extent_dirty(free_space_cache, start, end, GFP_NOFS);
}
return 0;
}
static int finish_current_insert(struct btrfs_trans_handle *trans, struct
btrfs_root *extent_root)
{
struct btrfs_key ins;
struct btrfs_extent_item extent_item;
int ret;
int err = 0;
u64 start;
u64 end;
struct btrfs_fs_info *info = extent_root->fs_info;
btrfs_set_stack_extent_refs(&extent_item, 1);
btrfs_set_key_type(&ins, BTRFS_EXTENT_ITEM_KEY);
btrfs_set_stack_extent_owner(&extent_item,
extent_root->root_key.objectid);
while(1) {
ret = find_first_extent_bit(&info->extent_ins, 0, &start,
&end, EXTENT_LOCKED);
if (ret)
break;
ins.objectid = start;
ins.offset = end + 1 - start;
err = btrfs_insert_item(trans, extent_root, &ins,
&extent_item, sizeof(extent_item));
clear_extent_bits(&info->extent_ins, start, end, EXTENT_LOCKED,
GFP_NOFS);
}
return 0;
}
static int pin_down_block(struct btrfs_root *root, u64 blocknr, int pending)
{
int err = 0;
struct extent_buffer *buf;
if (!pending) {
buf = btrfs_find_tree_block(root, blocknr);
if (buf) {
if (btrfs_buffer_uptodate(buf)) {
u64 transid =
root->fs_info->running_transaction->transid;
if (btrfs_header_generation(buf) == transid) {
free_extent_buffer(buf);
return 0;
}
}
free_extent_buffer(buf);
}
set_extent_dirty(&root->fs_info->pinned_extents,
blocknr, blocknr, GFP_NOFS);
} else {
set_extent_bits(&root->fs_info->pending_del,
blocknr, blocknr, EXTENT_LOCKED, GFP_NOFS);
}
BUG_ON(err < 0);
return 0;
}
/*
* remove an extent from the root, returns 0 on success
*/
static int __free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
*root, u64 blocknr, u64 num_blocks, int pin,
int mark_free)
{
struct btrfs_path *path;
struct btrfs_key key;
struct btrfs_fs_info *info = root->fs_info;
struct btrfs_root *extent_root = info->extent_root;
struct extent_buffer *leaf;
int ret;
struct btrfs_extent_item *ei;
u32 refs;
key.objectid = blocknr;
btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
key.offset = num_blocks;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
ret = btrfs_search_slot(trans, extent_root, &key, path, -1, 1);
if (ret < 0)
return ret;
BUG_ON(ret);
leaf = path->nodes[0];
ei = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_extent_item);
refs = btrfs_extent_refs(leaf, ei);
BUG_ON(refs == 0);
refs -= 1;
btrfs_set_extent_refs(leaf, ei, refs);
btrfs_mark_buffer_dirty(leaf);
if (refs == 0) {
u64 super_blocks_used, root_blocks_used;
if (pin) {
ret = pin_down_block(root, blocknr, 0);
BUG_ON(ret);
}
/* block accounting for super block */
super_blocks_used = btrfs_super_blocks_used(&info->super_copy);
btrfs_set_super_blocks_used(&info->super_copy,
super_blocks_used - num_blocks);
/* block accounting for root item */
root_blocks_used = btrfs_root_used(&root->root_item);
btrfs_set_root_used(&root->root_item,
root_blocks_used - num_blocks);
ret = btrfs_del_item(trans, extent_root, path);
if (ret) {
return ret;
}
ret = update_block_group(trans, root, blocknr, num_blocks, 0,
mark_free, 0);
BUG_ON(ret);
}
btrfs_free_path(path);
finish_current_insert(trans, extent_root);
return ret;
}
/*
* find all the blocks marked as pending in the radix tree and remove
* them from the extent map
*/
static int del_pending_extents(struct btrfs_trans_handle *trans, struct
btrfs_root *extent_root)
{
int ret;
int err = 0;
u64 start;
u64 end;
struct extent_map_tree *pending_del;
struct extent_map_tree *pinned_extents;
pending_del = &extent_root->fs_info->pending_del;
pinned_extents = &extent_root->fs_info->pinned_extents;
while(1) {
ret = find_first_extent_bit(pending_del, 0, &start, &end,
EXTENT_LOCKED);
if (ret)
break;
set_extent_dirty(pinned_extents, start, end, GFP_NOFS);
clear_extent_bits(pending_del, start, end, EXTENT_LOCKED,
GFP_NOFS);
ret = __free_extent(trans, extent_root,
start, end + 1 - start, 0, 0);
if (ret)
err = ret;
}
return err;
}
/*
* remove an extent from the root, returns 0 on success
*/
int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
*root, u64 blocknr, u64 num_blocks, int pin)
{
struct btrfs_root *extent_root = root->fs_info->extent_root;
int pending_ret;
int ret;
if (root == extent_root) {
pin_down_block(root, blocknr, 1);
return 0;
}
ret = __free_extent(trans, root, blocknr, num_blocks, pin, pin == 0);
pending_ret = del_pending_extents(trans, root->fs_info->extent_root);
return ret ? ret : pending_ret;
}
/*
* walks the btree of allocated extents and find a hole of a given size.
* The key ins is changed to record the hole:
* ins->objectid == block start
* ins->flags = BTRFS_EXTENT_ITEM_KEY
* ins->offset == number of blocks
* Any available blocks before search_start are skipped.
*/
static int find_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
*orig_root, u64 num_blocks, u64 empty_size,
u64 search_start, u64 search_end, u64 hint_block,
struct btrfs_key *ins, u64 exclude_start,
u64 exclude_nr, int data)
{
struct btrfs_path *path;
struct btrfs_key key;
int ret;
u64 hole_size = 0;
int slot = 0;
u64 last_block = 0;
u64 orig_search_start = search_start;
int start_found;
struct extent_buffer *l;
struct btrfs_root * root = orig_root->fs_info->extent_root;
struct btrfs_fs_info *info = root->fs_info;
int total_needed = num_blocks;
int level;
struct btrfs_block_group_cache *block_group;
int full_scan = 0;
int wrapped = 0;
u64 cached_search_start = 0;
WARN_ON(num_blocks < 1);
btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
level = btrfs_header_level(root->node);
if (search_end == (u64)-1)
search_end = btrfs_super_total_blocks(&info->super_copy);
if (hint_block) {
block_group = btrfs_lookup_block_group(info, hint_block);
block_group = btrfs_find_block_group(root, block_group,
hint_block, data, 1);
} else {
block_group = btrfs_find_block_group(root,
trans->block_group, 0,
data, 1);
}
total_needed += empty_size;
path = btrfs_alloc_path();
check_failed:
search_start = find_search_start(root, &block_group,
search_start, total_needed, data);
cached_search_start = search_start;
btrfs_init_path(path);
ins->objectid = search_start;
ins->offset = 0;
start_found = 0;
path->reada = 2;
ret = btrfs_search_slot(trans, root, ins, path, 0, 0);
if (ret < 0)
goto error;
if (path->slots[0] > 0) {
path->slots[0]--;
}
l = path->nodes[0];
btrfs_item_key_to_cpu(l, &key, path->slots[0]);
/*
* a rare case, go back one key if we hit a block group item
* instead of an extent item
*/
if (btrfs_key_type(&key) != BTRFS_EXTENT_ITEM_KEY &&
key.objectid + key.offset >= search_start) {
ins->objectid = key.objectid;
ins->offset = key.offset - 1;
btrfs_release_path(root, path);
ret = btrfs_search_slot(trans, root, ins, path, 0, 0);
if (ret < 0)
goto error;
if (path->slots[0] > 0) {
path->slots[0]--;
}
}
while (1) {
l = path->nodes[0];
slot = path->slots[0];
if (slot >= btrfs_header_nritems(l)) {
ret = btrfs_next_leaf(root, path);
if (ret == 0)
continue;
if (ret < 0)
goto error;
if (!start_found) {
ins->objectid = search_start;
ins->offset = search_end - search_start;
start_found = 1;
goto check_pending;
}
ins->objectid = last_block > search_start ?
last_block : search_start;
ins->offset = search_end - ins->objectid;
goto check_pending;
}
btrfs_item_key_to_cpu(l, &key, slot);
if (key.objectid >= search_start && key.objectid > last_block &&
start_found) {
if (last_block < search_start)
last_block = search_start;
hole_size = key.objectid - last_block;
if (hole_size >= num_blocks) {
ins->objectid = last_block;
ins->offset = hole_size;
goto check_pending;
}
}
if (btrfs_key_type(&key) != BTRFS_EXTENT_ITEM_KEY) {
if (!start_found) {
last_block = key.objectid;
start_found = 1;
}
goto next;
}
start_found = 1;
last_block = key.objectid + key.offset;
if (!full_scan && last_block >= block_group->key.objectid +
block_group->key.offset) {
btrfs_release_path(root, path);
search_start = block_group->key.objectid +
block_group->key.offset * 2;
goto new_group;
}
next:
path->slots[0]++;
cond_resched();
}
check_pending:
/* we have to make sure we didn't find an extent that has already
* been allocated by the map tree or the original allocation
*/
btrfs_release_path(root, path);
BUG_ON(ins->objectid < search_start);
if (ins->objectid + num_blocks >= search_end)
goto enospc;
if (test_range_bit(&info->extent_ins, ins->objectid,
ins->objectid + num_blocks -1, EXTENT_LOCKED, 0)) {
search_start = ins->objectid + num_blocks;
goto new_group;
}
if (test_range_bit(&info->pinned_extents, ins->objectid,
ins->objectid + num_blocks -1, EXTENT_DIRTY, 0)) {
search_start = ins->objectid + num_blocks;
goto new_group;
}
if (exclude_nr > 0 && (ins->objectid + num_blocks > exclude_start &&
ins->objectid < exclude_start + exclude_nr)) {
search_start = exclude_start + exclude_nr;
goto new_group;
}
if (!data) {
block_group = btrfs_lookup_block_group(info, ins->objectid);
if (block_group)
trans->block_group = block_group;
}
ins->offset = num_blocks;
btrfs_free_path(path);
return 0;
new_group:
if (search_start + num_blocks >= search_end) {
enospc:
search_start = orig_search_start;
if (full_scan) {
ret = -ENOSPC;
goto error;
}
if (wrapped) {
if (!full_scan)
total_needed -= empty_size;
full_scan = 1;
} else
wrapped = 1;
}
block_group = btrfs_lookup_block_group(info, search_start);
cond_resched();
if (!full_scan)
block_group = btrfs_find_block_group(root, block_group,
search_start, data, 0);
goto check_failed;
error:
btrfs_release_path(root, path);
btrfs_free_path(path);
return ret;
}
/*
* finds a free extent and does all the dirty work required for allocation
* returns the key for the extent through ins, and a tree buffer for
* the first block of the extent through buf.
*
* returns 0 if everything worked, non-zero otherwise.
*/
int btrfs_alloc_extent(struct btrfs_trans_handle *trans,
struct btrfs_root *root, u64 owner,
u64 num_blocks, u64 empty_size, u64 hint_block,
u64 search_end, struct btrfs_key *ins, int data)
{
int ret;
int pending_ret;
u64 super_blocks_used, root_blocks_used;
u64 search_start = 0;
struct btrfs_fs_info *info = root->fs_info;
struct btrfs_root *extent_root = info->extent_root;
struct btrfs_extent_item extent_item;
btrfs_set_stack_extent_refs(&extent_item, 1);
btrfs_set_stack_extent_owner(&extent_item, owner);
WARN_ON(num_blocks < 1);
ret = find_free_extent(trans, root, num_blocks, empty_size,
search_start, search_end, hint_block, ins,
trans->alloc_exclude_start,
trans->alloc_exclude_nr, data);
BUG_ON(ret);
if (ret)
return ret;
/* block accounting for super block */
super_blocks_used = btrfs_super_blocks_used(&info->super_copy);
btrfs_set_super_blocks_used(&info->super_copy, super_blocks_used +
num_blocks);
/* block accounting for root item */
root_blocks_used = btrfs_root_used(&root->root_item);
btrfs_set_root_used(&root->root_item, root_blocks_used +
num_blocks);
clear_extent_dirty(&root->fs_info->free_space_cache,
ins->objectid, ins->objectid + ins->offset - 1,
GFP_NOFS);
if (root == extent_root) {
BUG_ON(num_blocks != 1);
set_extent_bits(&root->fs_info->extent_ins, ins->objectid,
ins->objectid + ins->offset - 1,
EXTENT_LOCKED, GFP_NOFS);
goto update_block;
}
WARN_ON(trans->alloc_exclude_nr);
trans->alloc_exclude_start = ins->objectid;
trans->alloc_exclude_nr = ins->offset;
ret = btrfs_insert_item(trans, extent_root, ins, &extent_item,
sizeof(extent_item));
trans->alloc_exclude_start = 0;
trans->alloc_exclude_nr = 0;
BUG_ON(ret);
finish_current_insert(trans, extent_root);
pending_ret = del_pending_extents(trans, extent_root);
if (ret) {
return ret;
}
if (pending_ret) {
return pending_ret;
}
update_block:
ret = update_block_group(trans, root, ins->objectid, ins->offset, 1, 0,
data);
BUG_ON(ret);
return 0;
}
/*
* helper function to allocate a block for a given tree
* returns the tree buffer or NULL.
*/
struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
struct btrfs_root *root, u64 hint,
u64 empty_size)
{
struct btrfs_key ins;
int ret;
struct extent_buffer *buf;
ret = btrfs_alloc_extent(trans, root, root->root_key.objectid,
1, empty_size, hint, (u64)-1, &ins, 0);
if (ret) {
BUG_ON(ret > 0);
return ERR_PTR(ret);
}
buf = btrfs_find_create_tree_block(root, ins.objectid);
if (!buf) {
btrfs_free_extent(trans, root, ins.objectid, 1, 0);
return ERR_PTR(-ENOMEM);
}
btrfs_set_buffer_uptodate(buf);
buf->alloc_addr = (unsigned long)__builtin_return_address(0);
set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
buf->start + buf->len - 1, GFP_NOFS);
/*
set_buffer_checked(buf);
set_buffer_defrag(buf);
*/
/* FIXME!!!!!!!!!!!!!!!!
set_radix_bit(&trans->transaction->dirty_pages, buf->pages[0]->index);
*/
trans->blocks_used++;
return buf;
}
static int drop_leaf_ref(struct btrfs_trans_handle *trans,
struct btrfs_root *root, struct extent_buffer *leaf)
{
struct btrfs_key key;
struct btrfs_file_extent_item *fi;
int i;
int nritems;
int ret;
BUG_ON(!btrfs_is_leaf(leaf));
nritems = btrfs_header_nritems(leaf);
for (i = 0; i < nritems; i++) {
u64 disk_blocknr;
btrfs_item_key_to_cpu(leaf, &key, i);
if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
continue;
fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
if (btrfs_file_extent_type(leaf, fi) ==
BTRFS_FILE_EXTENT_INLINE)
continue;
/*
* FIXME make sure to insert a trans record that
* repeats the snapshot del on crash
*/
disk_blocknr = btrfs_file_extent_disk_blocknr(leaf, fi);
if (disk_blocknr == 0)
continue;
ret = btrfs_free_extent(trans, root, disk_blocknr,
btrfs_file_extent_disk_num_blocks(leaf, fi), 0);
BUG_ON(ret);
}
return 0;
}
static void reada_walk_down(struct btrfs_root *root,
struct extent_buffer *node)
{
int i;
u32 nritems;
u64 blocknr;
int ret;
u32 refs;
nritems = btrfs_header_nritems(node);
for (i = 0; i < nritems; i++) {
blocknr = btrfs_node_blockptr(node, i);
ret = lookup_extent_ref(NULL, root, blocknr, 1, &refs);
BUG_ON(ret);
if (refs != 1)
continue;
mutex_unlock(&root->fs_info->fs_mutex);
ret = readahead_tree_block(root, blocknr);
cond_resched();
mutex_lock(&root->fs_info->fs_mutex);
if (ret)
break;
}
}
/*
* helper function for drop_snapshot, this walks down the tree dropping ref
* counts as it goes.
*/
static int walk_down_tree(struct btrfs_trans_handle *trans, struct btrfs_root
*root, struct btrfs_path *path, int *level)
{
struct extent_buffer *next;
struct extent_buffer *cur;
u64 blocknr;
int ret;
u32 refs;
WARN_ON(*level < 0);
WARN_ON(*level >= BTRFS_MAX_LEVEL);
ret = lookup_extent_ref(trans, root,
extent_buffer_blocknr(path->nodes[*level]),
1, &refs);
BUG_ON(ret);
if (refs > 1)
goto out;
/*
* walk down to the last node level and free all the leaves
*/
while(*level >= 0) {
WARN_ON(*level < 0);
WARN_ON(*level >= BTRFS_MAX_LEVEL);
cur = path->nodes[*level];
if (*level > 0 && path->slots[*level] == 0)
reada_walk_down(root, cur);
if (btrfs_header_level(cur) != *level)
WARN_ON(1);
if (path->slots[*level] >=
btrfs_header_nritems(cur))
break;
if (*level == 0) {
ret = drop_leaf_ref(trans, root, cur);
BUG_ON(ret);
break;
}
blocknr = btrfs_node_blockptr(cur, path->slots[*level]);
ret = lookup_extent_ref(trans, root, blocknr, 1, &refs);
BUG_ON(ret);
if (refs != 1) {
path->slots[*level]++;
ret = btrfs_free_extent(trans, root, blocknr, 1, 1);
BUG_ON(ret);
continue;
}
next = btrfs_find_tree_block(root, blocknr);
if (!next || !btrfs_buffer_uptodate(next)) {
free_extent_buffer(next);
mutex_unlock(&root->fs_info->fs_mutex);
next = read_tree_block(root, blocknr);
mutex_lock(&root->fs_info->fs_mutex);
/* we dropped the lock, check one more time */
ret = lookup_extent_ref(trans, root, blocknr, 1, &refs);
BUG_ON(ret);
if (refs != 1) {
path->slots[*level]++;
free_extent_buffer(next);
ret = btrfs_free_extent(trans, root,
blocknr, 1, 1);
BUG_ON(ret);
continue;
}
}
WARN_ON(*level <= 0);
if (path->nodes[*level-1])
free_extent_buffer(path->nodes[*level-1]);
path->nodes[*level-1] = next;
*level = btrfs_header_level(next);
path->slots[*level] = 0;
}
out:
WARN_ON(*level < 0);
WARN_ON(*level >= BTRFS_MAX_LEVEL);
ret = btrfs_free_extent(trans, root,
extent_buffer_blocknr(path->nodes[*level]), 1, 1);
free_extent_buffer(path->nodes[*level]);
path->nodes[*level] = NULL;
*level += 1;
BUG_ON(ret);
return 0;
}
/*
* helper for dropping snapshots. This walks back up the tree in the path
* to find the first node higher up where we haven't yet gone through
* all the slots
*/
static int walk_up_tree(struct btrfs_trans_handle *trans, struct btrfs_root
*root, struct btrfs_path *path, int *level)
{
int i;
int slot;
int ret;
struct btrfs_root_item *root_item = &root->root_item;
for(i = *level; i < BTRFS_MAX_LEVEL - 1 && path->nodes[i]; i++) {
slot = path->slots[i];
if (slot < btrfs_header_nritems(path->nodes[i]) - 1) {
struct extent_buffer *node;
struct btrfs_disk_key disk_key;
node = path->nodes[i];
path->slots[i]++;
*level = i;
WARN_ON(*level == 0);
btrfs_node_key(node, &disk_key, path->slots[i]);
memcpy(&root_item->drop_progress,
&disk_key, sizeof(disk_key));
root_item->drop_level = i;
return 0;
} else {
ret = btrfs_free_extent(trans, root,
extent_buffer_blocknr(path->nodes[*level]),
1, 1);
BUG_ON(ret);
free_extent_buffer(path->nodes[*level]);
path->nodes[*level] = NULL;
*level = i + 1;
}
}
return 1;
}
/*
* drop the reference count on the tree rooted at 'snap'. This traverses
* the tree freeing any blocks that have a ref count of zero after being
* decremented.
*/
int btrfs_drop_snapshot(struct btrfs_trans_handle *trans, struct btrfs_root
*root)
{
int ret = 0;
int wret;
int level;
struct btrfs_path *path;
int i;
int orig_level;
struct btrfs_root_item *root_item = &root->root_item;
path = btrfs_alloc_path();
BUG_ON(!path);
level = btrfs_header_level(root->node);
orig_level = level;
if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
path->nodes[level] = root->node;
extent_buffer_get(root->node);
path->slots[level] = 0;
} else {
struct btrfs_key key;
struct btrfs_disk_key found_key;
struct extent_buffer *node;
btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
level = root_item->drop_level;
path->lowest_level = level;
wret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
if (wret < 0) {
ret = wret;
goto out;
}
node = path->nodes[level];
btrfs_node_key(node, &found_key, path->slots[level]);
WARN_ON(memcmp(&found_key, &root_item->drop_progress,
sizeof(found_key)));
}
while(1) {
wret = walk_down_tree(trans, root, path, &level);
if (wret > 0)
break;
if (wret < 0)
ret = wret;
wret = walk_up_tree(trans, root, path, &level);
if (wret > 0)
break;
if (wret < 0)
ret = wret;
ret = -EAGAIN;
break;
}
for (i = 0; i <= orig_level; i++) {
if (path->nodes[i]) {
free_extent_buffer(path->nodes[i]);
path->nodes[i] = 0;
}
}
out:
btrfs_free_path(path);
return ret;
}
int btrfs_free_block_groups(struct btrfs_fs_info *info)
{
u64 start;
u64 end;
int ret;
while(1) {
ret = find_first_extent_bit(&info->block_group_cache, 0,
&start, &end, (unsigned int)-1);
if (ret)
break;
clear_extent_bits(&info->block_group_cache, start,
end, (unsigned int)-1, GFP_NOFS);
}
while(1) {
ret = find_first_extent_bit(&info->free_space_cache, 0,
&start, &end, EXTENT_DIRTY);
if (ret)
break;
clear_extent_dirty(&info->free_space_cache, start,
end, GFP_NOFS);
}
return 0;
}
int btrfs_read_block_groups(struct btrfs_root *root)
{
struct btrfs_path *path;
int ret;
int err = 0;
int bit;
struct btrfs_block_group_cache *cache;
struct btrfs_fs_info *info = root->fs_info;
struct extent_map_tree *block_group_cache;
struct btrfs_key key;
struct btrfs_key found_key;
struct extent_buffer *leaf;
u64 group_size_blocks;
block_group_cache = &info->block_group_cache;
group_size_blocks = BTRFS_BLOCK_GROUP_SIZE >>
info->sb->s_blocksize_bits;
root = info->extent_root;
key.objectid = 0;
key.offset = group_size_blocks;
btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
while(1) {
ret = btrfs_search_slot(NULL, info->extent_root,
&key, path, 0, 0);
if (ret != 0) {
err = ret;
break;
}
leaf = path->nodes[0];
btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
cache = kmalloc(sizeof(*cache), GFP_NOFS);
if (!cache) {
err = -1;
break;
}
read_extent_buffer(leaf, &cache->item,
btrfs_item_ptr_offset(leaf, path->slots[0]),
sizeof(cache->item));
memcpy(&cache->key, &found_key, sizeof(found_key));
cache->cached = 0;
key.objectid = found_key.objectid + found_key.offset;
btrfs_release_path(root, path);
if (cache->item.flags & BTRFS_BLOCK_GROUP_DATA) {
bit = BLOCK_GROUP_DATA;
cache->data = 1;
} else {
bit = BLOCK_GROUP_METADATA;
cache->data = 0;
}
/* use EXTENT_LOCKED to prevent merging */
set_extent_bits(block_group_cache, found_key.objectid,
found_key.objectid + found_key.offset - 1,
bit | EXTENT_LOCKED, GFP_NOFS);
set_state_private(block_group_cache, found_key.objectid,
(u64)cache);
if (key.objectid >=
btrfs_super_total_blocks(&info->super_copy))
break;
}
btrfs_free_path(path);
return 0;
}