btrfs-progs/disk-io.c

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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"
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#include "transaction.h"
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static int allocated_blocks = 0;
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int cache_max = 10000;
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struct dev_lookup {
u64 block_start;
u64 num_blocks;
u64 device_id;
int fd;
};
int btrfs_insert_dev_radix(struct btrfs_root *root,
int fd,
u64 device_id,
u64 block_start,
u64 num_blocks)
{
struct dev_lookup *lookup;
int ret;
lookup = malloc(sizeof(*lookup));
if (!lookup)
return -ENOMEM;
lookup->block_start = block_start;
lookup->num_blocks = num_blocks;
lookup->fd = fd;
lookup->device_id = device_id;
printf("inserting into dev radix %Lu %Lu\n", block_start, num_blocks);
ret = radix_tree_insert(&root->fs_info->dev_radix, block_start +
num_blocks - 1, lookup);
return ret;
}
int btrfs_map_bh_to_logical(struct btrfs_root *root, struct btrfs_buffer *bh,
u64 logical)
{
struct dev_lookup *lookup[2];
int ret;
root = root->fs_info->dev_root;
ret = radix_tree_gang_lookup(&root->fs_info->dev_radix,
(void **)lookup,
(unsigned long)logical,
ARRAY_SIZE(lookup));
if (ret == 0 || lookup[0]->block_start > logical ||
lookup[0]->block_start + lookup[0]->num_blocks <= logical) {
ret = -1;
goto out;
}
bh->fd = lookup[0]->fd;
bh->dev_blocknr = logical - lookup[0]->block_start;
ret = 0;
out:
return ret;
}
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static int check_tree_block(struct btrfs_root *root, struct btrfs_buffer *buf)
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{
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if (buf->blocknr != btrfs_header_blocknr(&buf->node.header))
BUG();
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if (memcmp(root->fs_info->disk_super->fsid, buf->node.header.fsid,
sizeof(buf->node.header.fsid)))
BUG();
return 0;
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}
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static int free_some_buffers(struct btrfs_root *root)
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{
struct list_head *node, *next;
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struct btrfs_buffer *b;
if (root->fs_info->cache_size < cache_max)
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return 0;
list_for_each_safe(node, next, &root->fs_info->cache) {
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b = list_entry(node, struct btrfs_buffer, cache);
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if (b->count == 1) {
BUG_ON(!list_empty(&b->dirty));
list_del_init(&b->cache);
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btrfs_block_release(root, b);
if (root->fs_info->cache_size < cache_max)
break;
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}
}
return 0;
}
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struct btrfs_buffer *alloc_tree_block(struct btrfs_root *root, u64 blocknr)
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{
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struct btrfs_buffer *buf;
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int ret;
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buf = malloc(sizeof(struct btrfs_buffer) + root->blocksize);
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if (!buf)
return buf;
allocated_blocks++;
buf->blocknr = blocknr;
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buf->count = 2;
INIT_LIST_HEAD(&buf->dirty);
free_some_buffers(root);
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radix_tree_preload(GFP_KERNEL);
ret = radix_tree_insert(&root->fs_info->cache_radix, blocknr, buf);
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radix_tree_preload_end();
list_add_tail(&buf->cache, &root->fs_info->cache);
root->fs_info->cache_size++;
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if (ret) {
free(buf);
return NULL;
}
return buf;
}
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struct btrfs_buffer *find_tree_block(struct btrfs_root *root, u64 blocknr)
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{
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struct btrfs_buffer *buf;
buf = radix_tree_lookup(&root->fs_info->cache_radix, blocknr);
if (buf) {
buf->count++;
} else {
buf = alloc_tree_block(root, blocknr);
if (!buf) {
BUG();
return NULL;
}
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}
return buf;
}
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struct btrfs_buffer *read_tree_block(struct btrfs_root *root, u64 blocknr)
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{
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struct btrfs_buffer *buf;
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int ret;
buf = radix_tree_lookup(&root->fs_info->cache_radix, blocknr);
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if (buf) {
buf->count++;
} else {
buf = alloc_tree_block(root, blocknr);
if (!buf)
return NULL;
btrfs_map_bh_to_logical(root, buf, blocknr);
ret = pread(buf->fd, &buf->node, root->blocksize,
buf->dev_blocknr * root->blocksize);
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if (ret != root->blocksize) {
free(buf);
return NULL;
}
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}
if (check_tree_block(root, buf))
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BUG();
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return buf;
}
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int dirty_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
struct btrfs_buffer *buf)
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{
if (!list_empty(&buf->dirty))
return 0;
list_add_tail(&buf->dirty, &root->fs_info->trans);
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buf->count++;
return 0;
}
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int clean_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
struct btrfs_buffer *buf)
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{
if (!list_empty(&buf->dirty)) {
list_del_init(&buf->dirty);
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btrfs_block_release(root, buf);
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}
return 0;
}
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int write_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
struct btrfs_buffer *buf)
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{
int ret;
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if (buf->blocknr != btrfs_header_blocknr(&buf->node.header))
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BUG();
btrfs_map_bh_to_logical(root, buf, buf->blocknr);
ret = pwrite(buf->fd, &buf->node, root->blocksize,
buf->dev_blocknr * root->blocksize);
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if (ret != root->blocksize)
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return ret;
return 0;
}
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static int __commit_transaction(struct btrfs_trans_handle *trans, struct
btrfs_root *root)
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{
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struct btrfs_buffer *b;
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int ret = 0;
int wret;
while(!list_empty(&root->fs_info->trans)) {
b = list_entry(root->fs_info->trans.next, struct btrfs_buffer,
dirty);
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list_del_init(&b->dirty);
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wret = write_tree_block(trans, root, b);
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if (wret)
ret = wret;
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btrfs_block_release(root, b);
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}
return ret;
}
static int commit_tree_roots(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info)
{
int ret;
u64 old_extent_block;
struct btrfs_root *tree_root = fs_info->tree_root;
struct btrfs_root *extent_root = fs_info->extent_root;
if (btrfs_super_device_root(fs_info->disk_super) !=
fs_info->dev_root->node->blocknr) {
btrfs_set_super_device_root(fs_info->disk_super,
fs_info->dev_root->node->blocknr);
}
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);
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ret = btrfs_update_root(trans, tree_root,
&extent_root->root_key,
&extent_root->root_item);
BUG_ON(ret);
}
return 0;
}
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int btrfs_commit_transaction(struct btrfs_trans_handle *trans, struct
btrfs_root *root, struct btrfs_super_block *s)
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{
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int ret = 0;
struct btrfs_buffer *snap = root->commit_root;
struct btrfs_key snap_key;
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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(trans, root->fs_info->tree_root,
&root->root_key, &root->root_item);
BUG_ON(ret);
ret = commit_tree_roots(trans, root->fs_info);
BUG_ON(ret);
ret = __commit_transaction(trans, root);
BUG_ON(ret);
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write_ctree_super(trans, root, s);
btrfs_finish_extent_commit(trans, root->fs_info->extent_root);
btrfs_finish_extent_commit(trans, root->fs_info->tree_root);
root->commit_root = root->node;
root->node->count++;
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ret = btrfs_drop_snapshot(trans, root, snap);
BUG_ON(ret);
ret = btrfs_del_root(trans, root->fs_info->tree_root, &snap_key);
BUG_ON(ret);
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root->fs_info->generation = root->root_key.offset + 1;
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return ret;
}
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static int __setup_root(struct btrfs_super_block *super,
struct btrfs_root *root,
struct btrfs_fs_info *fs_info,
u64 objectid, int fp)
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{
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root->node = NULL;
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root->commit_root = NULL;
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root->blocksize = btrfs_super_blocksize(super);
root->ref_cows = 0;
root->fs_info = fs_info;
memset(&root->root_key, 0, sizeof(root->root_key));
memset(&root->root_item, 0, sizeof(root->root_item));
root->root_key.objectid = objectid;
return 0;
}
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static int find_and_setup_root(struct btrfs_super_block *super,
struct btrfs_root *tree_root,
struct btrfs_fs_info *fs_info,
u64 objectid,
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struct btrfs_root *root, int fp)
{
int ret;
__setup_root(super, root, fs_info, 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);
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return 0;
}
int btrfs_open_disk(struct btrfs_root *root, u64 device_id,
u64 block_start, u64 num_blocks,
char *filename, int name_len)
{
char *null_filename;
int fd;
int ret;
null_filename = malloc(name_len + 1);
if (!null_filename)
return -ENOMEM;
memcpy(null_filename, filename, name_len);
null_filename[name_len] = '\0';
fd = open(null_filename, O_RDWR);
if (fd < 0) {
ret = -1;
goto out;
}
ret = btrfs_insert_dev_radix(root, fd, device_id,
block_start, num_blocks);
BUG_ON(ret);
ret = 0;
out:
free(null_filename);
return ret;
}
static int read_device_info(struct btrfs_root *root)
{
struct btrfs_path path;
int ret;
struct btrfs_key key;
struct btrfs_leaf *leaf;
struct btrfs_device_item *dev_item;
int nritems;
int slot;
root = root->fs_info->dev_root;
btrfs_init_path(&path);
key.objectid = 0;
key.offset = 0;
key.flags = 0;
btrfs_set_key_type(&key, BTRFS_DEV_ITEM_KEY);
ret = btrfs_search_slot(NULL, root, &key, &path, 0, 0);
leaf = &path.nodes[0]->leaf;
nritems = btrfs_header_nritems(&leaf->header);
while(1) {
slot = path.slots[0];
if (slot >= nritems) {
ret = btrfs_next_leaf(root, &path);
if (ret)
break;
leaf = &path.nodes[0]->leaf;
nritems = btrfs_header_nritems(&leaf->header);
slot = path.slots[0];
}
btrfs_disk_key_to_cpu(&key, &leaf->items[slot].key);
if (btrfs_key_type(&key) != BTRFS_DEV_ITEM_KEY) {
path.slots[0]++;
continue;
}
dev_item = btrfs_item_ptr(leaf, slot, struct btrfs_device_item);
if (btrfs_device_id(dev_item) !=
btrfs_super_device_id(root->fs_info->disk_super)) {
printf("found key %Lu %Lu\n", key.objectid, key.offset);
ret = btrfs_open_disk(root, btrfs_device_id(dev_item),
key.objectid, key.offset,
(char *)(dev_item + 1),
btrfs_device_pathlen(dev_item));
BUG_ON(ret);
}
path.slots[0]++;
}
btrfs_release_path(root, &path);
return 0;
}
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struct btrfs_root *open_ctree(char *filename, struct btrfs_super_block *super)
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{
int fp;
fp = open(filename, O_CREAT | O_RDWR, 0600);
if (fp < 0) {
return NULL;
}
return open_ctree_fd(fp, super);
}
struct btrfs_root *open_ctree_fd(int fp, struct btrfs_super_block *super)
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{
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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));
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struct btrfs_root *dev_root = malloc(sizeof(struct btrfs_root));
struct btrfs_fs_info *fs_info = malloc(sizeof(*fs_info));
struct dev_lookup *dev_lookup;
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int ret;
INIT_RADIX_TREE(&fs_info->cache_radix, GFP_KERNEL);
INIT_RADIX_TREE(&fs_info->pinned_radix, GFP_KERNEL);
INIT_RADIX_TREE(&fs_info->dev_radix, GFP_KERNEL);
INIT_LIST_HEAD(&fs_info->trans);
INIT_LIST_HEAD(&fs_info->cache);
fs_info->cache_size = 0;
fs_info->fp = fp;
fs_info->running_transaction = NULL;
fs_info->fs_root = root;
fs_info->tree_root = tree_root;
fs_info->extent_root = extent_root;
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fs_info->dev_root = dev_root;
fs_info->last_inode_alloc = 0;
fs_info->last_inode_alloc_dirid = 0;
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fs_info->disk_super = super;
memset(&fs_info->current_insert, 0, sizeof(fs_info->current_insert));
memset(&fs_info->last_insert, 0, sizeof(fs_info->last_insert));
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ret = pread(fp, super, sizeof(struct btrfs_super_block),
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BTRFS_SUPER_INFO_OFFSET);
if (ret == 0 || btrfs_super_root(super) == 0) {
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BUG();
return NULL;
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}
BUG_ON(ret < 0);
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__setup_root(super, dev_root, fs_info, BTRFS_DEV_TREE_OBJECTID, fp);
dev_lookup = malloc(sizeof(*dev_lookup));
dev_lookup->fd = fp;
dev_lookup->device_id = btrfs_super_device_id(super);
dev_lookup->block_start = btrfs_super_device_block_start(super);
dev_lookup->num_blocks = btrfs_super_device_num_blocks(super);
ret = radix_tree_insert(&fs_info->dev_radix,
dev_lookup->block_start +
dev_lookup->num_blocks - 1, dev_lookup);
BUG_ON(ret);
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dev_root->node = read_tree_block(dev_root,
btrfs_super_device_root(super));
ret = read_device_info(dev_root);
BUG_ON(ret);
__setup_root(super, tree_root, fs_info, 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, fs_info,
BTRFS_EXTENT_TREE_OBJECTID, extent_root, fp);
BUG_ON(ret);
ret = find_and_setup_root(super, tree_root, fs_info,
BTRFS_FS_TREE_OBJECTID, root, fp);
BUG_ON(ret);
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root->commit_root = root->node;
root->node->count++;
root->ref_cows = 1;
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root->fs_info->generation = root->root_key.offset + 1;
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return root;
}
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int write_ctree_super(struct btrfs_trans_handle *trans, struct btrfs_root
*root, struct btrfs_super_block *s)
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{
int ret;
btrfs_set_super_root(s, root->fs_info->tree_root->node->blocknr);
ret = pwrite(root->fs_info->fp, s, sizeof(*s),
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BTRFS_SUPER_INFO_OFFSET);
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if (ret != sizeof(*s)) {
fprintf(stderr, "failed to write new super block err %d\n", ret);
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return ret;
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}
return 0;
}
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static int drop_cache(struct btrfs_root *root)
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{
while(!list_empty(&root->fs_info->cache)) {
struct btrfs_buffer *b = list_entry(root->fs_info->cache.next,
struct btrfs_buffer,
cache);
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list_del_init(&b->cache);
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btrfs_block_release(root, b);
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}
return 0;
}
static int free_dev_radix(struct btrfs_fs_info *fs_info)
{
struct dev_lookup *lookup[8];
int ret;
int i;
while(1) {
ret = radix_tree_gang_lookup(&fs_info->dev_radix,
(void **)lookup, 0,
ARRAY_SIZE(lookup));
if (!ret)
break;
for (i = 0; i < ret; i++) {
if (lookup[i]->device_id !=
btrfs_super_device_id(fs_info->disk_super))
close(lookup[i]->fd);
radix_tree_delete(&fs_info->dev_radix,
lookup[i]->block_start +
lookup[i]->num_blocks - 1);
free(lookup[i]);
}
}
return 0;
}
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int close_ctree(struct btrfs_root *root, struct btrfs_super_block *s)
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{
int ret;
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struct btrfs_trans_handle *trans;
trans = root->fs_info->running_transaction;
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btrfs_commit_transaction(trans, root, s);
ret = commit_tree_roots(trans, root->fs_info);
BUG_ON(ret);
ret = __commit_transaction(trans, root);
BUG_ON(ret);
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write_ctree_super(trans, root, s);
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drop_cache(root);
BUG_ON(!list_empty(&root->fs_info->trans));
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free_dev_radix(root->fs_info);
close(root->fs_info->fp);
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if (root->node)
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btrfs_block_release(root, root->node);
if (root->fs_info->extent_root->node)
btrfs_block_release(root->fs_info->extent_root,
root->fs_info->extent_root->node);
if (root->fs_info->tree_root->node)
btrfs_block_release(root->fs_info->tree_root,
root->fs_info->tree_root->node);
if (root->fs_info->dev_root->node)
btrfs_block_release(root->fs_info->dev_root,
root->fs_info->dev_root->node);
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btrfs_block_release(root, root->commit_root);
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free(root);
printf("on close %d blocks are allocated\n", allocated_blocks);
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return 0;
}
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void btrfs_block_release(struct btrfs_root *root, struct btrfs_buffer *buf)
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{
buf->count--;
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if (buf->count < 0)
BUG();
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if (buf->count == 0) {
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BUG_ON(!list_empty(&buf->cache));
BUG_ON(!list_empty(&buf->dirty));
if (!radix_tree_lookup(&root->fs_info->cache_radix,
buf->blocknr))
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BUG();
radix_tree_delete(&root->fs_info->cache_radix, buf->blocknr);
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memset(buf, 0, sizeof(*buf));
free(buf);
BUG_ON(allocated_blocks == 0);
allocated_blocks--;
BUG_ON(root->fs_info->cache_size == 0);
root->fs_info->cache_size--;
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}
}