linux/fs/btrfs/disk-io.c

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#define _XOPEN_SOURCE 500
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include "kerncompat.h"
#include "radix-tree.h"
#include "ctree.h"
#include "disk-io.h"
static int allocated_blocks = 0;
int cache_max = 10000;
static int check_tree_block(struct btrfs_root *root, struct btrfs_buffer *buf)
{
if (buf->blocknr != btrfs_header_blocknr(&buf->node.header))
BUG();
if (root->node && btrfs_header_parentid(&buf->node.header) !=
btrfs_header_parentid(&root->node->node.header))
BUG();
return 0;
}
static int free_some_buffers(struct btrfs_root *root)
{
struct list_head *node, *next;
struct btrfs_buffer *b;
if (root->cache_size < cache_max)
return 0;
list_for_each_safe(node, next, &root->cache) {
b = list_entry(node, struct btrfs_buffer, cache);
if (b->count == 1) {
BUG_ON(!list_empty(&b->dirty));
list_del_init(&b->cache);
btrfs_block_release(root, b);
if (root->cache_size < cache_max)
break;
}
}
return 0;
}
struct btrfs_buffer *alloc_tree_block(struct btrfs_root *root, u64 blocknr)
{
struct btrfs_buffer *buf;
int ret;
buf = malloc(sizeof(struct btrfs_buffer) + root->blocksize);
if (!buf)
return buf;
allocated_blocks++;
buf->blocknr = blocknr;
buf->count = 2;
INIT_LIST_HEAD(&buf->dirty);
free_some_buffers(root);
radix_tree_preload(GFP_KERNEL);
ret = radix_tree_insert(&root->cache_radix, blocknr, buf);
radix_tree_preload_end();
list_add_tail(&buf->cache, &root->cache);
root->cache_size++;
if (ret) {
free(buf);
return NULL;
}
return buf;
}
struct btrfs_buffer *find_tree_block(struct btrfs_root *root, u64 blocknr)
{
struct btrfs_buffer *buf;
buf = radix_tree_lookup(&root->cache_radix, blocknr);
if (buf) {
buf->count++;
} else {
buf = alloc_tree_block(root, blocknr);
if (!buf) {
BUG();
return NULL;
}
}
return buf;
}
struct btrfs_buffer *read_tree_block(struct btrfs_root *root, u64 blocknr)
{
loff_t offset = blocknr * root->blocksize;
struct btrfs_buffer *buf;
int ret;
buf = radix_tree_lookup(&root->cache_radix, blocknr);
if (buf) {
buf->count++;
} else {
buf = alloc_tree_block(root, blocknr);
if (!buf)
return NULL;
ret = pread(root->fp, &buf->node, root->blocksize, offset);
if (ret != root->blocksize) {
free(buf);
return NULL;
}
}
if (check_tree_block(root, buf))
BUG();
return buf;
}
int dirty_tree_block(struct btrfs_root *root, struct btrfs_buffer *buf)
{
if (!list_empty(&buf->dirty))
return 0;
list_add_tail(&buf->dirty, &root->trans);
buf->count++;
return 0;
}
int clean_tree_block(struct btrfs_root *root, struct btrfs_buffer *buf)
{
if (!list_empty(&buf->dirty)) {
list_del_init(&buf->dirty);
btrfs_block_release(root, buf);
}
return 0;
}
int write_tree_block(struct btrfs_root *root, struct btrfs_buffer *buf)
{
u64 blocknr = buf->blocknr;
loff_t offset = blocknr * root->blocksize;
int ret;
if (buf->blocknr != btrfs_header_blocknr(&buf->node.header))
BUG();
ret = pwrite(root->fp, &buf->node, root->blocksize, offset);
if (ret != root->blocksize)
return ret;
return 0;
}
static int __commit_transaction(struct btrfs_root *root)
{
struct btrfs_buffer *b;
int ret = 0;
int wret;
while(!list_empty(&root->trans)) {
b = list_entry(root->trans.next, struct btrfs_buffer, dirty);
list_del_init(&b->dirty);
wret = write_tree_block(root, b);
if (wret)
ret = wret;
btrfs_block_release(root, b);
}
return ret;
}
static int commit_extent_and_tree_roots(struct btrfs_root *tree_root,
struct btrfs_root *extent_root)
{
int ret;
u64 old_extent_block;
while(1) {
old_extent_block = btrfs_root_blocknr(&extent_root->root_item);
if (old_extent_block == extent_root->node->blocknr)
break;
btrfs_set_root_blocknr(&extent_root->root_item,
extent_root->node->blocknr);
ret = btrfs_update_root(tree_root,
&extent_root->root_key,
&extent_root->root_item);
BUG_ON(ret);
}
__commit_transaction(extent_root);
__commit_transaction(tree_root);
return 0;
}
int btrfs_commit_transaction(struct btrfs_root *root,
struct btrfs_super_block *s)
{
int ret = 0;
struct btrfs_buffer *snap = root->commit_root;
struct btrfs_key snap_key;
ret = __commit_transaction(root);
BUG_ON(ret);
if (root->commit_root == root->node)
return 0;
memcpy(&snap_key, &root->root_key, sizeof(snap_key));
root->root_key.offset++;
btrfs_set_root_blocknr(&root->root_item, root->node->blocknr);
ret = btrfs_insert_root(root->tree_root, &root->root_key,
&root->root_item);
BUG_ON(ret);
ret = commit_extent_and_tree_roots(root->tree_root, root->extent_root);
BUG_ON(ret);
write_ctree_super(root, s);
btrfs_finish_extent_commit(root->extent_root);
btrfs_finish_extent_commit(root->tree_root);
root->commit_root = root->node;
root->node->count++;
ret = btrfs_drop_snapshot(root, snap);
BUG_ON(ret);
ret = btrfs_del_root(root->tree_root, &snap_key);
BUG_ON(ret);
return ret;
}
static int __setup_root(struct btrfs_super_block *super,
struct btrfs_root *root, u64 objectid, int fp)
{
INIT_LIST_HEAD(&root->trans);
INIT_LIST_HEAD(&root->cache);
root->cache_size = 0;
root->fp = fp;
root->node = NULL;
root->commit_root = NULL;
root->blocksize = btrfs_super_blocksize(super);
root->ref_cows = 0;
memset(&root->current_insert, 0, sizeof(root->current_insert));
memset(&root->last_insert, 0, sizeof(root->last_insert));
memset(&root->root_key, 0, sizeof(root->root_key));
memset(&root->root_item, 0, sizeof(root->root_item));
return 0;
}
static int find_and_setup_root(struct btrfs_super_block *super,
struct btrfs_root *tree_root, u64 objectid,
struct btrfs_root *root, int fp)
{
int ret;
__setup_root(super, root, objectid, fp);
ret = btrfs_find_last_root(tree_root, objectid,
&root->root_item, &root->root_key);
BUG_ON(ret);
root->node = read_tree_block(root,
btrfs_root_blocknr(&root->root_item));
BUG_ON(!root->node);
return 0;
}
struct btrfs_root *open_ctree(char *filename, struct btrfs_super_block *super)
{
struct btrfs_root *root = malloc(sizeof(struct btrfs_root));
struct btrfs_root *extent_root = malloc(sizeof(struct btrfs_root));
struct btrfs_root *tree_root = malloc(sizeof(struct btrfs_root));
int fp;
int ret;
root->extent_root = extent_root;
root->tree_root = tree_root;
extent_root->extent_root = extent_root;
extent_root->tree_root = tree_root;
tree_root->extent_root = extent_root;
tree_root->tree_root = tree_root;
fp = open(filename, O_CREAT | O_RDWR, 0600);
if (fp < 0) {
free(root);
return NULL;
}
INIT_RADIX_TREE(&root->cache_radix, GFP_KERNEL);
INIT_RADIX_TREE(&root->pinned_radix, GFP_KERNEL);
INIT_RADIX_TREE(&extent_root->pinned_radix, GFP_KERNEL);
INIT_RADIX_TREE(&extent_root->cache_radix, GFP_KERNEL);
INIT_RADIX_TREE(&tree_root->pinned_radix, GFP_KERNEL);
INIT_RADIX_TREE(&tree_root->cache_radix, GFP_KERNEL);
ret = pread(fp, super, sizeof(struct btrfs_super_block),
BTRFS_SUPER_INFO_OFFSET);
if (ret == 0 || btrfs_super_root(super) == 0) {
printf("making new FS!\n");
ret = mkfs(fp, 0, 1024);
if (ret)
return NULL;
ret = pread(fp, super, sizeof(struct btrfs_super_block),
BTRFS_SUPER_INFO_OFFSET);
if (ret != sizeof(struct btrfs_super_block))
return NULL;
}
BUG_ON(ret < 0);
__setup_root(super, tree_root, BTRFS_ROOT_TREE_OBJECTID, fp);
tree_root->node = read_tree_block(tree_root, btrfs_super_root(super));
BUG_ON(!tree_root->node);
ret = find_and_setup_root(super, tree_root, BTRFS_EXTENT_TREE_OBJECTID,
extent_root, fp);
BUG_ON(ret);
ret = find_and_setup_root(super, tree_root, BTRFS_FS_TREE_OBJECTID,
root, fp);
BUG_ON(ret);
root->commit_root = root->node;
root->node->count++;
root->ref_cows = 1;
return root;
}
int write_ctree_super(struct btrfs_root *root, struct btrfs_super_block *s)
{
int ret;
btrfs_set_super_root(s, root->tree_root->node->blocknr);
ret = pwrite(root->fp, s, sizeof(*s),
BTRFS_SUPER_INFO_OFFSET);
if (ret != sizeof(*s)) {
fprintf(stderr, "failed to write new super block err %d\n", ret);
return ret;
}
return 0;
}
static int drop_cache(struct btrfs_root *root)
{
while(!list_empty(&root->cache)) {
struct btrfs_buffer *b = list_entry(root->cache.next,
struct btrfs_buffer, cache);
list_del_init(&b->cache);
btrfs_block_release(root, b);
}
return 0;
}
int close_ctree(struct btrfs_root *root, struct btrfs_super_block *s)
{
int ret;
btrfs_commit_transaction(root, s);
ret = commit_extent_and_tree_roots(root->tree_root, root->extent_root);
BUG_ON(ret);
write_ctree_super(root, s);
drop_cache(root->extent_root);
drop_cache(root->tree_root);
drop_cache(root);
BUG_ON(!list_empty(&root->trans));
BUG_ON(!list_empty(&root->extent_root->trans));
BUG_ON(!list_empty(&root->tree_root->trans));
close(root->fp);
if (root->node)
btrfs_block_release(root, root->node);
if (root->extent_root->node)
btrfs_block_release(root->extent_root, root->extent_root->node);
if (root->tree_root->node)
btrfs_block_release(root->tree_root, root->tree_root->node);
btrfs_block_release(root, root->commit_root);
free(root);
printf("on close %d blocks are allocated\n", allocated_blocks);
return 0;
}
void btrfs_block_release(struct btrfs_root *root, struct btrfs_buffer *buf)
{
buf->count--;
if (buf->count < 0)
BUG();
if (buf->count == 0) {
BUG_ON(!list_empty(&buf->cache));
BUG_ON(!list_empty(&buf->dirty));
if (!radix_tree_lookup(&root->cache_radix, buf->blocknr))
BUG();
radix_tree_delete(&root->cache_radix, buf->blocknr);
memset(buf, 0, sizeof(*buf));
free(buf);
BUG_ON(allocated_blocks == 0);
allocated_blocks--;
BUG_ON(root->cache_size == 0);
root->cache_size--;
}
}