[deliverable/linux.git] / fs / btrfs / disk-io.c

#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"
#include "transaction.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->fs_info->cache_size < cache_max)
		return 0;
	list_for_each_safe(node, next, &root->fs_info->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->fs_info->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->fs_info->cache_radix, blocknr, buf);
	radix_tree_preload_end();
	list_add_tail(&buf->cache, &root->fs_info->cache);
	root->fs_info->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->fs_info->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->fs_info->cache_radix, blocknr);
	if (buf) {
		buf->count++;
	} else {
		buf = alloc_tree_block(root, blocknr);
		if (!buf)
			return NULL;
		ret = pread(root->fs_info->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_trans_handle *trans, struct btrfs_root *root,
		     struct btrfs_buffer *buf)
{
	if (!list_empty(&buf->dirty))
		return 0;
	list_add_tail(&buf->dirty, &root->fs_info->trans);
	buf->count++;
	return 0;
}

int clean_tree_block(struct btrfs_trans_handle *trans, 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_trans_handle *trans, 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->fs_info->fp, &buf->node, root->blocksize, offset);
	if (ret != root->blocksize)
		return ret;
	return 0;
}

static int __commit_transaction(struct btrfs_trans_handle *trans, struct
				btrfs_root *root)
{
	struct btrfs_buffer *b;
	int ret = 0;
	int wret;
	while(!list_empty(&root->fs_info->trans)) {
		b = list_entry(root->fs_info->trans.next, struct btrfs_buffer,
			       dirty);
		list_del_init(&b->dirty);
		wret = write_tree_block(trans, root, b);
		if (wret)
			ret = wret;
		btrfs_block_release(root, b);
	}
	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;
	struct btrfs_root *inode_root = fs_info->inode_root;

	btrfs_set_root_blocknr(&inode_root->root_item,
			       inode_root->node->blocknr);
	ret = btrfs_update_root(trans, tree_root,
				&inode_root->root_key,
				&inode_root->root_item);
	BUG_ON(ret);
	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(trans, tree_root,
					&extent_root->root_key,
					&extent_root->root_item);
		BUG_ON(ret);
	}
	return 0;
}

int btrfs_commit_transaction(struct btrfs_trans_handle *trans, struct
			     btrfs_root *root, struct btrfs_super_block *s)
{
	int ret = 0;
	struct btrfs_buffer *snap = root->commit_root;
	struct btrfs_key snap_key;

	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);

	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++;
	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);
	root->fs_info->generation = root->root_key.offset + 1;

	return ret;
}

static int __setup_root(struct btrfs_super_block *super,
			struct btrfs_root *root,
			struct btrfs_fs_info *fs_info,
			u64 objectid, int fp)
{
	root->node = NULL;
	root->commit_root = NULL;
	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));
	return 0;
}

static int find_and_setup_root(struct btrfs_super_block *super,
			       struct btrfs_root *tree_root,
			       struct btrfs_fs_info *fs_info,
			       u64 objectid,
			       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);
	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));
	struct btrfs_root *inode_root = malloc(sizeof(struct btrfs_root));
	struct btrfs_fs_info *fs_info = malloc(sizeof(*fs_info));
	int fp;
	int ret;

	fp = open(filename, O_CREAT | O_RDWR, 0600);
	if (fp < 0) {
		free(root);
		return NULL;
	}
	INIT_RADIX_TREE(&fs_info->cache_radix, GFP_KERNEL);
	INIT_RADIX_TREE(&fs_info->pinned_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;
	fs_info->inode_root = inode_root;
	fs_info->last_inode_alloc = 0;
	fs_info->last_inode_alloc_dirid = 0;
	memset(&fs_info->current_insert, 0, sizeof(fs_info->current_insert));
	memset(&fs_info->last_insert, 0, sizeof(fs_info->last_insert));

	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, 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_INODE_MAP_OBJECTID, inode_root, fp);
	BUG_ON(ret);

	ret = find_and_setup_root(super, tree_root, fs_info,
				  BTRFS_FS_TREE_OBJECTID, root, fp);
	BUG_ON(ret);

	root->commit_root = root->node;
	root->node->count++;
	root->ref_cows = 1;
	root->fs_info->generation = root->root_key.offset + 1;
	return root;
}

int write_ctree_super(struct btrfs_trans_handle *trans, struct btrfs_root
		      *root, struct btrfs_super_block *s)
{
	int ret;
	btrfs_set_super_root(s, root->fs_info->tree_root->node->blocknr);
	ret = pwrite(root->fs_info->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->fs_info->cache)) {
		struct btrfs_buffer *b = list_entry(root->fs_info->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;
	struct btrfs_trans_handle *trans;

	trans = root->fs_info->running_transaction;
	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);
	write_ctree_super(trans, root, s);
	drop_cache(root);
	BUG_ON(!list_empty(&root->fs_info->trans));

	close(root->fs_info->fp);
	if (root->node)
		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->inode_root->node)
		btrfs_block_release(root->fs_info->inode_root,
				    root->fs_info->inode_root->node);
	if (root->fs_info->tree_root->node)
		btrfs_block_release(root->fs_info->tree_root,
				    root->fs_info->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->fs_info->cache_radix,
				       buf->blocknr))
			BUG();
		radix_tree_delete(&root->fs_info->cache_radix, buf->blocknr);
		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--;
	}
}
Commit	Line	Data
	1	#define _XOPEN_SOURCE 500
	2	#include <stdio.h>
	3	#include <stdlib.h>
	4	#include <sys/types.h>
	5	#include <sys/stat.h>
	6	#include <fcntl.h>
	7	#include <unistd.h>
	8	#include "kerncompat.h"
	9	#include "radix-tree.h"
	10	#include "ctree.h"
	11	#include "disk-io.h"
	12	#include "transaction.h"
	13
	14	static int allocated_blocks = 0;
	15	int cache_max = 10000;
	16
	17	static int check_tree_block(struct btrfs_root root, struct btrfs_buffer buf)
	18	{
	19	if (buf->blocknr != btrfs_header_blocknr(&buf->node.header))
	20	BUG();
	21	if (root->node && btrfs_header_parentid(&buf->node.header) !=
	22	btrfs_header_parentid(&root->node->node.header))
	23	BUG();
	24	return 0;
	25	}
	26
	27	static int free_some_buffers(struct btrfs_root *root)
	28	{
	29	struct list_head node, next;
	30	struct btrfs_buffer *b;
	31	if (root->fs_info->cache_size < cache_max)
	32	return 0;
	33	list_for_each_safe(node, next, &root->fs_info->cache) {
	34	b = list_entry(node, struct btrfs_buffer, cache);
	35	if (b->count == 1) {
	36	BUG_ON(!list_empty(&b->dirty));
	37	list_del_init(&b->cache);
	38	btrfs_block_release(root, b);
	39	if (root->fs_info->cache_size < cache_max)
	40	break;
	41	}
	42	}
	43	return 0;
	44	}
	45
	46	struct btrfs_buffer alloc_tree_block(struct btrfs_root root, u64 blocknr)
	47	{
	48	struct btrfs_buffer *buf;
	49	int ret;
	50
	51	buf = malloc(sizeof(struct btrfs_buffer) + root->blocksize);
	52	if (!buf)
	53	return buf;
	54	allocated_blocks++;
	55	buf->blocknr = blocknr;
	56	buf->count = 2;
	57	INIT_LIST_HEAD(&buf->dirty);
	58	free_some_buffers(root);
	59	radix_tree_preload(GFP_KERNEL);
	60	ret = radix_tree_insert(&root->fs_info->cache_radix, blocknr, buf);
	61	radix_tree_preload_end();
	62	list_add_tail(&buf->cache, &root->fs_info->cache);
	63	root->fs_info->cache_size++;
	64	if (ret) {
	65	free(buf);
	66	return NULL;
	67	}
	68	return buf;
	69	}
	70
	71	struct btrfs_buffer find_tree_block(struct btrfs_root root, u64 blocknr)
	72	{
	73	struct btrfs_buffer *buf;
	74	buf = radix_tree_lookup(&root->fs_info->cache_radix, blocknr);
	75	if (buf) {
	76	buf->count++;
	77	} else {
	78	buf = alloc_tree_block(root, blocknr);
	79	if (!buf) {
	80	BUG();
	81	return NULL;
	82	}
	83	}
	84	return buf;
	85	}
	86
	87	struct btrfs_buffer read_tree_block(struct btrfs_root root, u64 blocknr)
	88	{
	89	loff_t offset = blocknr * root->blocksize;
	90	struct btrfs_buffer *buf;
	91	int ret;
	92
	93	buf = radix_tree_lookup(&root->fs_info->cache_radix, blocknr);
	94	if (buf) {
	95	buf->count++;
	96	} else {
	97	buf = alloc_tree_block(root, blocknr);
	98	if (!buf)
	99	return NULL;
	100	ret = pread(root->fs_info->fp, &buf->node, root->blocksize,
	101	offset);
	102	if (ret != root->blocksize) {
	103	free(buf);
	104	return NULL;
	105	}
	106	}
	107	if (check_tree_block(root, buf))
	108	BUG();
	109	return buf;
	110	}
	111
	112	int dirty_tree_block(struct btrfs_trans_handle trans, struct btrfs_root root,
	113	struct btrfs_buffer *buf)
	114	{
	115	if (!list_empty(&buf->dirty))
	116	return 0;
	117	list_add_tail(&buf->dirty, &root->fs_info->trans);
	118	buf->count++;
	119	return 0;
	120	}
	121
	122	int clean_tree_block(struct btrfs_trans_handle trans, struct btrfs_root root,
	123	struct btrfs_buffer *buf)
	124	{
	125	if (!list_empty(&buf->dirty)) {
	126	list_del_init(&buf->dirty);
	127	btrfs_block_release(root, buf);
	128	}
	129	return 0;
	130	}
	131
	132	int write_tree_block(struct btrfs_trans_handle trans, struct btrfs_root root,
	133	struct btrfs_buffer *buf)
	134	{
	135	u64 blocknr = buf->blocknr;
	136	loff_t offset = blocknr * root->blocksize;
	137	int ret;
	138
	139	if (buf->blocknr != btrfs_header_blocknr(&buf->node.header))
	140	BUG();
	141	ret = pwrite(root->fs_info->fp, &buf->node, root->blocksize, offset);
	142	if (ret != root->blocksize)
	143	return ret;
	144	return 0;
	145	}
	146
	147	static int __commit_transaction(struct btrfs_trans_handle *trans, struct
	148	btrfs_root *root)
	149	{
	150	struct btrfs_buffer *b;
	151	int ret = 0;
	152	int wret;
	153	while(!list_empty(&root->fs_info->trans)) {
	154	b = list_entry(root->fs_info->trans.next, struct btrfs_buffer,
	155	dirty);
	156	list_del_init(&b->dirty);
	157	wret = write_tree_block(trans, root, b);
	158	if (wret)
	159	ret = wret;
	160	btrfs_block_release(root, b);
	161	}
	162	return ret;
	163	}
	164
	165	static int commit_tree_roots(struct btrfs_trans_handle *trans,
	166	struct btrfs_fs_info *fs_info)
	167	{
	168	int ret;
	169	u64 old_extent_block;
	170	struct btrfs_root *tree_root = fs_info->tree_root;
	171	struct btrfs_root *extent_root = fs_info->extent_root;
	172	struct btrfs_root *inode_root = fs_info->inode_root;
	173
	174	btrfs_set_root_blocknr(&inode_root->root_item,
	175	inode_root->node->blocknr);
	176	ret = btrfs_update_root(trans, tree_root,
	177	&inode_root->root_key,
	178	&inode_root->root_item);
	179	BUG_ON(ret);
	180	while(1) {
	181	old_extent_block = btrfs_root_blocknr(&extent_root->root_item);
	182	if (old_extent_block == extent_root->node->blocknr)
	183	break;
	184	btrfs_set_root_blocknr(&extent_root->root_item,
	185	extent_root->node->blocknr);
	186	ret = btrfs_update_root(trans, tree_root,
	187	&extent_root->root_key,
	188	&extent_root->root_item);
	189	BUG_ON(ret);
	190	}
	191	return 0;
	192	}
	193
	194	int btrfs_commit_transaction(struct btrfs_trans_handle *trans, struct
	195	btrfs_root root, struct btrfs_super_block s)
	196	{
	197	int ret = 0;
	198	struct btrfs_buffer *snap = root->commit_root;
	199	struct btrfs_key snap_key;
	200
	201	if (root->commit_root == root->node)
	202	return 0;
	203
	204	memcpy(&snap_key, &root->root_key, sizeof(snap_key));
	205	root->root_key.offset++;
	206
	207	btrfs_set_root_blocknr(&root->root_item, root->node->blocknr);
	208	ret = btrfs_insert_root(trans, root->fs_info->tree_root,
	209	&root->root_key, &root->root_item);
	210	BUG_ON(ret);
	211
	212	ret = commit_tree_roots(trans, root->fs_info);
	213	BUG_ON(ret);
	214
	215	ret = __commit_transaction(trans, root);
	216	BUG_ON(ret);
	217
	218	write_ctree_super(trans, root, s);
	219	btrfs_finish_extent_commit(trans, root->fs_info->extent_root);
	220	btrfs_finish_extent_commit(trans, root->fs_info->tree_root);
	221
	222	root->commit_root = root->node;
	223	root->node->count++;
	224	ret = btrfs_drop_snapshot(trans, root, snap);
	225	BUG_ON(ret);
	226
	227	ret = btrfs_del_root(trans, root->fs_info->tree_root, &snap_key);
	228	BUG_ON(ret);
	229	root->fs_info->generation = root->root_key.offset + 1;
	230
	231	return ret;
	232	}
	233
	234	static int __setup_root(struct btrfs_super_block *super,
	235	struct btrfs_root *root,
	236	struct btrfs_fs_info *fs_info,
	237	u64 objectid, int fp)
	238	{
	239	root->node = NULL;
	240	root->commit_root = NULL;
	241	root->blocksize = btrfs_super_blocksize(super);
	242	root->ref_cows = 0;
	243	root->fs_info = fs_info;
	244	memset(&root->root_key, 0, sizeof(root->root_key));
	245	memset(&root->root_item, 0, sizeof(root->root_item));
	246	return 0;
	247	}
	248
	249	static int find_and_setup_root(struct btrfs_super_block *super,
	250	struct btrfs_root *tree_root,
	251	struct btrfs_fs_info *fs_info,
	252	u64 objectid,
	253	struct btrfs_root *root, int fp)
	254	{
	255	int ret;
	256
	257	__setup_root(super, root, fs_info, objectid, fp);
	258	ret = btrfs_find_last_root(tree_root, objectid,
	259	&root->root_item, &root->root_key);
	260	BUG_ON(ret);
	261
	262	root->node = read_tree_block(root,
	263	btrfs_root_blocknr(&root->root_item));
	264	BUG_ON(!root->node);
	265	return 0;
	266	}
	267
	268	struct btrfs_root open_ctree(char filename, struct btrfs_super_block *super)
	269	{
	270	struct btrfs_root *root = malloc(sizeof(struct btrfs_root));
	271	struct btrfs_root *extent_root = malloc(sizeof(struct btrfs_root));
	272	struct btrfs_root *tree_root = malloc(sizeof(struct btrfs_root));
	273	struct btrfs_root *inode_root = malloc(sizeof(struct btrfs_root));
	274	struct btrfs_fs_info fs_info = malloc(sizeof(fs_info));
	275	int fp;
	276	int ret;
	277
	278	fp = open(filename, O_CREAT \| O_RDWR, 0600);
	279	if (fp < 0) {
	280	free(root);
	281	return NULL;
	282	}
	283	INIT_RADIX_TREE(&fs_info->cache_radix, GFP_KERNEL);
	284	INIT_RADIX_TREE(&fs_info->pinned_radix, GFP_KERNEL);
	285	INIT_LIST_HEAD(&fs_info->trans);
	286	INIT_LIST_HEAD(&fs_info->cache);
	287	fs_info->cache_size = 0;
	288	fs_info->fp = fp;
	289	fs_info->running_transaction = NULL;
	290	fs_info->fs_root = root;
	291	fs_info->tree_root = tree_root;
	292	fs_info->extent_root = extent_root;
	293	fs_info->inode_root = inode_root;
	294	fs_info->last_inode_alloc = 0;
	295	fs_info->last_inode_alloc_dirid = 0;
	296	memset(&fs_info->current_insert, 0, sizeof(fs_info->current_insert));
	297	memset(&fs_info->last_insert, 0, sizeof(fs_info->last_insert));
	298
	299	ret = pread(fp, super, sizeof(struct btrfs_super_block),
	300	BTRFS_SUPER_INFO_OFFSET);
	301	if (ret == 0 \|\| btrfs_super_root(super) == 0) {
	302	printf("making new FS!\n");
	303	ret = mkfs(fp, 0, 1024);
	304	if (ret)
	305	return NULL;
	306	ret = pread(fp, super, sizeof(struct btrfs_super_block),
	307	BTRFS_SUPER_INFO_OFFSET);
	308	if (ret != sizeof(struct btrfs_super_block))
	309	return NULL;
	310	}
	311	BUG_ON(ret < 0);
	312
	313	__setup_root(super, tree_root, fs_info, BTRFS_ROOT_TREE_OBJECTID, fp);
	314	tree_root->node = read_tree_block(tree_root, btrfs_super_root(super));
	315	BUG_ON(!tree_root->node);
	316
	317	ret = find_and_setup_root(super, tree_root, fs_info,
	318	BTRFS_EXTENT_TREE_OBJECTID, extent_root, fp);
	319	BUG_ON(ret);
	320
	321	ret = find_and_setup_root(super, tree_root, fs_info,
	322	BTRFS_INODE_MAP_OBJECTID, inode_root, fp);
	323	BUG_ON(ret);
	324
	325	ret = find_and_setup_root(super, tree_root, fs_info,
	326	BTRFS_FS_TREE_OBJECTID, root, fp);
	327	BUG_ON(ret);
	328
	329	root->commit_root = root->node;
	330	root->node->count++;
	331	root->ref_cows = 1;
	332	root->fs_info->generation = root->root_key.offset + 1;
	333	return root;
	334	}
	335
	336	int write_ctree_super(struct btrfs_trans_handle *trans, struct btrfs_root
	337	root, struct btrfs_super_block s)
	338	{
	339	int ret;
	340	btrfs_set_super_root(s, root->fs_info->tree_root->node->blocknr);
	341	ret = pwrite(root->fs_info->fp, s, sizeof(*s),
	342	BTRFS_SUPER_INFO_OFFSET);
	343	if (ret != sizeof(*s)) {
	344	fprintf(stderr, "failed to write new super block err %d\n", ret);
	345	return ret;
	346	}
	347	return 0;
	348	}
	349
	350	static int drop_cache(struct btrfs_root *root)
	351	{
	352	while(!list_empty(&root->fs_info->cache)) {
	353	struct btrfs_buffer *b = list_entry(root->fs_info->cache.next,
	354	struct btrfs_buffer,
	355	cache);
	356	list_del_init(&b->cache);
	357	btrfs_block_release(root, b);
	358	}
	359	return 0;
	360	}
	361	int close_ctree(struct btrfs_root root, struct btrfs_super_block s)
	362	{
	363	int ret;
	364	struct btrfs_trans_handle *trans;
	365
	366	trans = root->fs_info->running_transaction;
	367	btrfs_commit_transaction(trans, root, s);
	368	ret = commit_tree_roots(trans, root->fs_info);
	369	BUG_ON(ret);
	370	ret = __commit_transaction(trans, root);
	371	BUG_ON(ret);
	372	write_ctree_super(trans, root, s);
	373	drop_cache(root);
	374	BUG_ON(!list_empty(&root->fs_info->trans));
	375
	376	close(root->fs_info->fp);
	377	if (root->node)
	378	btrfs_block_release(root, root->node);
	379	if (root->fs_info->extent_root->node)
	380	btrfs_block_release(root->fs_info->extent_root,
	381	root->fs_info->extent_root->node);
	382	if (root->fs_info->inode_root->node)
	383	btrfs_block_release(root->fs_info->inode_root,
	384	root->fs_info->inode_root->node);
	385	if (root->fs_info->tree_root->node)
	386	btrfs_block_release(root->fs_info->tree_root,
	387	root->fs_info->tree_root->node);
	388	btrfs_block_release(root, root->commit_root);
	389	free(root);
	390	printf("on close %d blocks are allocated\n", allocated_blocks);
	391	return 0;
	392	}
	393
	394	void btrfs_block_release(struct btrfs_root root, struct btrfs_buffer buf)
	395	{
	396	buf->count--;
	397	if (buf->count < 0)
	398	BUG();
	399	if (buf->count == 0) {
	400	BUG_ON(!list_empty(&buf->cache));
	401	BUG_ON(!list_empty(&buf->dirty));
	402	if (!radix_tree_lookup(&root->fs_info->cache_radix,
	403	buf->blocknr))
	404	BUG();
	405	radix_tree_delete(&root->fs_info->cache_radix, buf->blocknr);
	406	memset(buf, 0, sizeof(*buf));
	407	free(buf);
	408	BUG_ON(allocated_blocks == 0);
	409	allocated_blocks--;
	410	BUG_ON(root->fs_info->cache_size == 0);
	411	root->fs_info->cache_size--;
	412	}
	413	}
	414