[linux-2.6-block.git] / fs / btrfs / disk-io.c

#include <linux/module.h>
#include <linux/fs.h>
#include <linux/blkdev.h>
#include <linux/crypto.h>
#include <linux/scatterlist.h>
#include <linux/swap.h>
#include <linux/radix-tree.h>
#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"
#include "btrfs_inode.h"

static int check_tree_block(struct btrfs_root *root, struct buffer_head *buf)
{
	struct btrfs_node *node = btrfs_buffer_node(buf);
	if (buf->b_blocknr != btrfs_header_blocknr(&node->header)) {
		BUG();
	}
	return 0;
}

struct buffer_head *btrfs_find_tree_block(struct btrfs_root *root, u64 blocknr)
{
	struct address_space *mapping = root->fs_info->btree_inode->i_mapping;
	int blockbits = root->fs_info->sb->s_blocksize_bits;
	unsigned long index = blocknr >> (PAGE_CACHE_SHIFT - blockbits);
	struct page *page;
	struct buffer_head *bh;
	struct buffer_head *head;
	struct buffer_head *ret = NULL;


	page = find_lock_page(mapping, index);
	if (!page)
		return NULL;

	if (!page_has_buffers(page))
		goto out_unlock;

	head = page_buffers(page);
	bh = head;
	do {
		if (buffer_mapped(bh) && bh->b_blocknr == blocknr) {
			ret = bh;
			get_bh(bh);
			goto out_unlock;
		}
		bh = bh->b_this_page;
	} while (bh != head);
out_unlock:
	unlock_page(page);
	if (ret) {
		touch_buffer(ret);
	}
	page_cache_release(page);
	return ret;
}

struct buffer_head *btrfs_find_create_tree_block(struct btrfs_root *root,
						 u64 blocknr)
{
	struct address_space *mapping = root->fs_info->btree_inode->i_mapping;
	int blockbits = root->fs_info->sb->s_blocksize_bits;
	unsigned long index = blocknr >> (PAGE_CACHE_SHIFT - blockbits);
	struct page *page;
	struct buffer_head *bh;
	struct buffer_head *head;
	struct buffer_head *ret = NULL;
	u64 first_block = index << (PAGE_CACHE_SHIFT - blockbits);

	page = grab_cache_page(mapping, index);
	if (!page)
		return NULL;

	if (!page_has_buffers(page))
		create_empty_buffers(page, root->fs_info->sb->s_blocksize, 0);
	head = page_buffers(page);
	bh = head;
	do {
		if (!buffer_mapped(bh)) {
			bh->b_bdev = root->fs_info->sb->s_bdev;
			bh->b_blocknr = first_block;
			set_buffer_mapped(bh);
		}
		if (bh->b_blocknr == blocknr) {
			ret = bh;
			get_bh(bh);
			goto out_unlock;
		}
		bh = bh->b_this_page;
		first_block++;
	} while (bh != head);
out_unlock:
	unlock_page(page);
	if (ret)
		touch_buffer(ret);
	page_cache_release(page);
	return ret;
}

static sector_t max_block(struct block_device *bdev)
{
	sector_t retval = ~((sector_t)0);
	loff_t sz = i_size_read(bdev->bd_inode);

	if (sz) {
		unsigned int size = block_size(bdev);
		unsigned int sizebits = blksize_bits(size);
		retval = (sz >> sizebits);
	}
	return retval;
}

static int btree_get_block(struct inode *inode, sector_t iblock,
			   struct buffer_head *bh, int create)
{
	if (iblock >= max_block(inode->i_sb->s_bdev)) {
		if (create)
			return -EIO;

		/*
		 * for reads, we're just trying to fill a partial page.
		 * return a hole, they will have to call get_block again
		 * before they can fill it, and they will get -EIO at that
		 * time
		 */
		return 0;
	}
	bh->b_bdev = inode->i_sb->s_bdev;
	bh->b_blocknr = iblock;
	set_buffer_mapped(bh);
	return 0;
}

int btrfs_csum_data(struct btrfs_root * root, char *data, size_t len,
		    char *result)
{
	struct scatterlist sg;
	struct crypto_hash *tfm = root->fs_info->hash_tfm;
	struct hash_desc desc;
	int ret;

	desc.tfm = tfm;
	desc.flags = 0;
	sg_init_one(&sg, data, len);
	spin_lock(&root->fs_info->hash_lock);
	ret = crypto_hash_digest(&desc, &sg, 1, result);
	spin_unlock(&root->fs_info->hash_lock);
	if (ret) {
		printk("sha256 digest failed\n");
	}
	return ret;
}
static int csum_tree_block(struct btrfs_root *root, struct buffer_head *bh,
			   int verify)
{
	char result[BTRFS_CSUM_SIZE];
	int ret;
	struct btrfs_node *node;

	ret = btrfs_csum_data(root, bh->b_data + BTRFS_CSUM_SIZE,
			      bh->b_size - BTRFS_CSUM_SIZE, result);
	if (ret)
		return ret;
	if (verify) {
		if (memcmp(bh->b_data, result, BTRFS_CSUM_SIZE)) {
			printk("checksum verify failed on %lu\n",
			       bh->b_blocknr);
			return 1;
		}
	} else {
		node = btrfs_buffer_node(bh);
		memcpy(node->header.csum, result, BTRFS_CSUM_SIZE);
	}
	return 0;
}

static int btree_writepage(struct page *page, struct writeback_control *wbc)
{
	struct buffer_head *bh;
	struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
	struct buffer_head *head;
	if (!page_has_buffers(page)) {
		create_empty_buffers(page, root->fs_info->sb->s_blocksize,
					(1 << BH_Dirty)|(1 << BH_Uptodate));
	}
	head = page_buffers(page);
	bh = head;
	do {
		if (buffer_dirty(bh))
			csum_tree_block(root, bh, 0);
		bh = bh->b_this_page;
	} while (bh != head);
	return block_write_full_page(page, btree_get_block, wbc);
}

static int btree_readpage(struct file * file, struct page * page)
{
	return block_read_full_page(page, btree_get_block);
}

static struct address_space_operations btree_aops = {
	.readpage	= btree_readpage,
	.writepage	= btree_writepage,
	.sync_page	= block_sync_page,
};

struct buffer_head *read_tree_block(struct btrfs_root *root, u64 blocknr)
{
	struct buffer_head *bh = NULL;

	bh = btrfs_find_create_tree_block(root, blocknr);
	if (!bh)
		return bh;
	if (buffer_uptodate(bh))
		goto uptodate;
	lock_buffer(bh);
	if (!buffer_uptodate(bh)) {
		get_bh(bh);
		bh->b_end_io = end_buffer_read_sync;
		submit_bh(READ, bh);
		wait_on_buffer(bh);
		if (!buffer_uptodate(bh))
			goto fail;
		csum_tree_block(root, bh, 1);
	} else {
		unlock_buffer(bh);
	}
uptodate:
	if (check_tree_block(root, bh))
		BUG();
	return bh;
fail:
	brelse(bh);
	return NULL;
}

int dirty_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
		     struct buffer_head *buf)
{
	WARN_ON(atomic_read(&buf->b_count) == 0);
	mark_buffer_dirty(buf);
	return 0;
}

int clean_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
		     struct buffer_head *buf)
{
	WARN_ON(atomic_read(&buf->b_count) == 0);
	clear_buffer_dirty(buf);
	return 0;
}

static int __setup_root(int blocksize,
			struct btrfs_root *root,
			struct btrfs_fs_info *fs_info,
			u64 objectid)
{
	root->node = NULL;
	root->inode = NULL;
	root->commit_root = NULL;
	root->blocksize = blocksize;
	root->ref_cows = 0;
	root->fs_info = fs_info;
	root->objectid = objectid;
	root->last_trans = 0;
	root->highest_inode = 0;
	root->last_inode_alloc = 0;
	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(int blocksize,
			       struct btrfs_root *tree_root,
			       struct btrfs_fs_info *fs_info,
			       u64 objectid,
			       struct btrfs_root *root)
{
	int ret;

	__setup_root(blocksize, root, fs_info, objectid);
	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 *btrfs_read_fs_root(struct btrfs_fs_info *fs_info,
				      struct btrfs_key *location)
{
	struct btrfs_root *root;
	struct btrfs_root *tree_root = fs_info->tree_root;
	struct btrfs_path *path;
	struct btrfs_leaf *l;
	u64 highest_inode;
	int ret = 0;

printk("read_fs_root looking for %Lu %Lu %u\n", location->objectid, location->offset, location->flags);
	root = radix_tree_lookup(&fs_info->fs_roots_radix,
				 (unsigned long)location->objectid);
	if (root) {
printk("found %p in cache\n", root);
		return root;
	}
	root = kmalloc(sizeof(*root), GFP_NOFS);
	if (!root) {
printk("failed1\n");
		return ERR_PTR(-ENOMEM);
	}
	if (location->offset == (u64)-1) {
		ret = find_and_setup_root(fs_info->sb->s_blocksize,
					  fs_info->tree_root, fs_info,
					  location->objectid, root);
		if (ret) {
printk("failed2\n");
			kfree(root);
			return ERR_PTR(ret);
		}
		goto insert;
	}

	__setup_root(fs_info->sb->s_blocksize, root, fs_info,
		     location->objectid);

	path = btrfs_alloc_path();
	BUG_ON(!path);
	ret = btrfs_search_slot(NULL, tree_root, location, path, 0, 0);
	if (ret != 0) {
printk("internal search_slot gives us %d\n", ret);
		if (ret > 0)
			ret = -ENOENT;
		goto out;
	}
	l = btrfs_buffer_leaf(path->nodes[0]);
	memcpy(&root->root_item,
	       btrfs_item_ptr(l, path->slots[0], struct btrfs_root_item),
	       sizeof(root->root_item));
	memcpy(&root->root_key, location, sizeof(*location));
	ret = 0;
out:
	btrfs_release_path(root, path);
	btrfs_free_path(path);
	if (ret) {
		kfree(root);
		return ERR_PTR(ret);
	}
	root->node = read_tree_block(root,
				     btrfs_root_blocknr(&root->root_item));
	BUG_ON(!root->node);
insert:
printk("inserting %p\n", root);
	root->ref_cows = 1;
	ret = radix_tree_insert(&fs_info->fs_roots_radix,
				(unsigned long)root->root_key.objectid,
				root);
	if (ret) {
printk("radix_tree_insert gives us %d\n", ret);
		brelse(root->node);
		kfree(root);
		return ERR_PTR(ret);
	}
	ret = btrfs_find_highest_inode(root, &highest_inode);
	if (ret == 0) {
		root->highest_inode = highest_inode;
		root->last_inode_alloc = highest_inode;
printk("highest inode is %Lu\n", highest_inode);
	}
printk("all worked\n");
	return root;
}

struct btrfs_root *open_ctree(struct super_block *sb)
{
	struct btrfs_root *extent_root = kmalloc(sizeof(struct btrfs_root),
						 GFP_NOFS);
	struct btrfs_root *dev_root = kmalloc(sizeof(struct btrfs_root),
						 GFP_NOFS);
	struct btrfs_root *tree_root = kmalloc(sizeof(struct btrfs_root),
					       GFP_NOFS);
	struct btrfs_fs_info *fs_info = kmalloc(sizeof(*fs_info),
						GFP_NOFS);
	int ret;
	struct btrfs_super_block *disk_super;

	init_bit_radix(&fs_info->pinned_radix);
	init_bit_radix(&fs_info->pending_del_radix);
	INIT_RADIX_TREE(&fs_info->fs_roots_radix, GFP_NOFS);
	sb_set_blocksize(sb, 4096);
	fs_info->running_transaction = NULL;
	fs_info->tree_root = tree_root;
	fs_info->extent_root = extent_root;
	fs_info->dev_root = dev_root;
	fs_info->sb = sb;
	fs_info->btree_inode = new_inode(sb);
	fs_info->btree_inode->i_ino = 1;
	fs_info->btree_inode->i_nlink = 1;
	fs_info->btree_inode->i_size = sb->s_bdev->bd_inode->i_size;
	fs_info->btree_inode->i_mapping->a_ops = &btree_aops;
	BTRFS_I(fs_info->btree_inode)->root = tree_root;
	memset(&BTRFS_I(fs_info->btree_inode)->location, 0,
	       sizeof(struct btrfs_key));
	insert_inode_hash(fs_info->btree_inode);
	mapping_set_gfp_mask(fs_info->btree_inode->i_mapping, GFP_NOFS);
	fs_info->hash_tfm = crypto_alloc_hash("sha256", 0, CRYPTO_ALG_ASYNC);
	spin_lock_init(&fs_info->hash_lock);
	if (!fs_info->hash_tfm || IS_ERR(fs_info->hash_tfm)) {
		printk("failed to allocate sha256 hash\n");
		return NULL;
	}
	mutex_init(&fs_info->trans_mutex);
	mutex_init(&fs_info->fs_mutex);
	memset(&fs_info->current_insert, 0, sizeof(fs_info->current_insert));
	memset(&fs_info->last_insert, 0, sizeof(fs_info->last_insert));

	__setup_root(sb->s_blocksize, dev_root,
		     fs_info, BTRFS_DEV_TREE_OBJECTID);

	__setup_root(sb->s_blocksize, tree_root,
		     fs_info, BTRFS_ROOT_TREE_OBJECTID);
	fs_info->sb_buffer = read_tree_block(tree_root,
					     BTRFS_SUPER_INFO_OFFSET /
					     sb->s_blocksize);

	if (!fs_info->sb_buffer)
		return NULL;
	disk_super = (struct btrfs_super_block *)fs_info->sb_buffer->b_data;
	if (!btrfs_super_root(disk_super))
		return NULL;

	fs_info->disk_super = disk_super;
	dev_root->node = read_tree_block(tree_root,
					  btrfs_super_device_root(disk_super));
	tree_root->node = read_tree_block(tree_root,
					  btrfs_super_root(disk_super));
	BUG_ON(!tree_root->node);

	mutex_lock(&fs_info->fs_mutex);
	ret = find_and_setup_root(sb->s_blocksize, tree_root, fs_info,
				  BTRFS_EXTENT_TREE_OBJECTID, extent_root);
	BUG_ON(ret);

	fs_info->generation = btrfs_super_generation(disk_super) + 1;
	memset(&fs_info->kobj, 0, sizeof(fs_info->kobj));
	kobj_set_kset_s(fs_info, btrfs_subsys);
	kobject_set_name(&fs_info->kobj, "%s", sb->s_id);
	kobject_register(&fs_info->kobj);
	mutex_unlock(&fs_info->fs_mutex);
	return tree_root;
}

int write_ctree_super(struct btrfs_trans_handle *trans, struct btrfs_root
		      *root)
{
	struct buffer_head *bh = root->fs_info->sb_buffer;

	btrfs_set_super_root(root->fs_info->disk_super,
			     root->fs_info->tree_root->node->b_blocknr);
	lock_buffer(bh);
	WARN_ON(atomic_read(&bh->b_count) < 1);
	clear_buffer_dirty(bh);
	csum_tree_block(root, bh, 0);
	bh->b_end_io = end_buffer_write_sync;
	get_bh(bh);
	submit_bh(WRITE, bh);
	wait_on_buffer(bh);
	if (!buffer_uptodate(bh)) {
		WARN_ON(1);
		return -EIO;
	}
	return 0;
}

static int free_fs_root(struct btrfs_fs_info *fs_info, struct btrfs_root *root)
{
	radix_tree_delete(&fs_info->fs_roots_radix,
			  (unsigned long)root->root_key.objectid);
	if (root->inode)
		iput(root->inode);
	if (root->node)
		brelse(root->node);
	if (root->commit_root)
		brelse(root->commit_root);
	kfree(root);
	return 0;
}

int del_fs_roots(struct btrfs_fs_info *fs_info)
{
	int ret;
	struct btrfs_root *gang[8];
	int i;

	while(1) {
		ret = radix_tree_gang_lookup(&fs_info->fs_roots_radix,
					     (void **)gang, 0,
					     ARRAY_SIZE(gang));
		if (!ret)
			break;
		for (i = 0; i < ret; i++)
			free_fs_root(fs_info, gang[i]);
	}
	return 0;
}

int close_ctree(struct btrfs_root *root)
{
	int ret;
	struct btrfs_trans_handle *trans;
	struct btrfs_fs_info *fs_info = root->fs_info;

	mutex_lock(&fs_info->fs_mutex);
	trans = btrfs_start_transaction(root, 1);
	btrfs_commit_transaction(trans, root);
	/* run commit again to  drop the original snapshot */
	trans = btrfs_start_transaction(root, 1);
	btrfs_commit_transaction(trans, root);
	ret = btrfs_write_and_wait_transaction(NULL, root);
	BUG_ON(ret);
	write_ctree_super(NULL, root);
	mutex_unlock(&fs_info->fs_mutex);

	if (fs_info->extent_root->node)
		btrfs_block_release(fs_info->extent_root,
				    fs_info->extent_root->node);
	if (fs_info->dev_root->node)
		btrfs_block_release(fs_info->dev_root,
				    fs_info->dev_root->node);
	if (fs_info->tree_root->node)
		btrfs_block_release(fs_info->tree_root,
				    fs_info->tree_root->node);
	btrfs_block_release(root, fs_info->sb_buffer);
	crypto_free_hash(fs_info->hash_tfm);
	truncate_inode_pages(fs_info->btree_inode->i_mapping, 0);
	iput(fs_info->btree_inode);
	del_fs_roots(fs_info);
	kfree(fs_info->extent_root);
	kfree(fs_info->tree_root);
	kobject_unregister(&fs_info->kobj);
	return 0;
}

void btrfs_block_release(struct btrfs_root *root, struct buffer_head *buf)
{
	brelse(buf);
}
Commit	Line	Data
	1	#include <linux/module.h>
	2	#include <linux/fs.h>
	3	#include <linux/blkdev.h>
	4	#include <linux/crypto.h>
	5	#include <linux/scatterlist.h>
	6	#include <linux/swap.h>
	7	#include <linux/radix-tree.h>
	8	#include "ctree.h"
	9	#include "disk-io.h"
	10	#include "transaction.h"
	11	#include "btrfs_inode.h"
	12
	13	static int check_tree_block(struct btrfs_root root, struct buffer_head buf)
	14	{
	15	struct btrfs_node *node = btrfs_buffer_node(buf);
	16	if (buf->b_blocknr != btrfs_header_blocknr(&node->header)) {
	17	BUG();
	18	}
	19	return 0;
	20	}
	21
	22	struct buffer_head btrfs_find_tree_block(struct btrfs_root root, u64 blocknr)
	23	{
	24	struct address_space *mapping = root->fs_info->btree_inode->i_mapping;
	25	int blockbits = root->fs_info->sb->s_blocksize_bits;
	26	unsigned long index = blocknr >> (PAGE_CACHE_SHIFT - blockbits);
	27	struct page *page;
	28	struct buffer_head *bh;
	29	struct buffer_head *head;
	30	struct buffer_head *ret = NULL;
	31
	32
	33	page = find_lock_page(mapping, index);
	34	if (!page)
	35	return NULL;
	36
	37	if (!page_has_buffers(page))
	38	goto out_unlock;
	39
	40	head = page_buffers(page);
	41	bh = head;
	42	do {
	43	if (buffer_mapped(bh) && bh->b_blocknr == blocknr) {
	44	ret = bh;
	45	get_bh(bh);
	46	goto out_unlock;
	47	}
	48	bh = bh->b_this_page;
	49	} while (bh != head);
	50	out_unlock:
	51	unlock_page(page);
	52	if (ret) {
	53	touch_buffer(ret);
	54	}
	55	page_cache_release(page);
	56	return ret;
	57	}
	58
	59	struct buffer_head btrfs_find_create_tree_block(struct btrfs_root root,
	60	u64 blocknr)
	61	{
	62	struct address_space *mapping = root->fs_info->btree_inode->i_mapping;
	63	int blockbits = root->fs_info->sb->s_blocksize_bits;
	64	unsigned long index = blocknr >> (PAGE_CACHE_SHIFT - blockbits);
	65	struct page *page;
	66	struct buffer_head *bh;
	67	struct buffer_head *head;
	68	struct buffer_head *ret = NULL;
	69	u64 first_block = index << (PAGE_CACHE_SHIFT - blockbits);
	70
	71	page = grab_cache_page(mapping, index);
	72	if (!page)
	73	return NULL;
	74
	75	if (!page_has_buffers(page))
	76	create_empty_buffers(page, root->fs_info->sb->s_blocksize, 0);
	77	head = page_buffers(page);
	78	bh = head;
	79	do {
	80	if (!buffer_mapped(bh)) {
	81	bh->b_bdev = root->fs_info->sb->s_bdev;
	82	bh->b_blocknr = first_block;
	83	set_buffer_mapped(bh);
	84	}
	85	if (bh->b_blocknr == blocknr) {
	86	ret = bh;
	87	get_bh(bh);
	88	goto out_unlock;
	89	}
	90	bh = bh->b_this_page;
	91	first_block++;
	92	} while (bh != head);
	93	out_unlock:
	94	unlock_page(page);
	95	if (ret)
	96	touch_buffer(ret);
	97	page_cache_release(page);
	98	return ret;
	99	}
	100
	101	static sector_t max_block(struct block_device *bdev)
	102	{
	103	sector_t retval = ~((sector_t)0);
	104	loff_t sz = i_size_read(bdev->bd_inode);
	105
	106	if (sz) {
	107	unsigned int size = block_size(bdev);
	108	unsigned int sizebits = blksize_bits(size);
	109	retval = (sz >> sizebits);
	110	}
	111	return retval;
	112	}
	113
	114	static int btree_get_block(struct inode *inode, sector_t iblock,
	115	struct buffer_head *bh, int create)
	116	{
	117	if (iblock >= max_block(inode->i_sb->s_bdev)) {
	118	if (create)
	119	return -EIO;
	120
	121	/*
	122	* for reads, we're just trying to fill a partial page.
	123	* return a hole, they will have to call get_block again
	124	* before they can fill it, and they will get -EIO at that
	125	* time
	126	*/
	127	return 0;
	128	}
	129	bh->b_bdev = inode->i_sb->s_bdev;
	130	bh->b_blocknr = iblock;
	131	set_buffer_mapped(bh);
	132	return 0;
	133	}
	134
	135	int btrfs_csum_data(struct btrfs_root * root, char *data, size_t len,
	136	char *result)
	137	{
	138	struct scatterlist sg;
	139	struct crypto_hash *tfm = root->fs_info->hash_tfm;
	140	struct hash_desc desc;
	141	int ret;
	142
	143	desc.tfm = tfm;
	144	desc.flags = 0;
	145	sg_init_one(&sg, data, len);
	146	spin_lock(&root->fs_info->hash_lock);
	147	ret = crypto_hash_digest(&desc, &sg, 1, result);
	148	spin_unlock(&root->fs_info->hash_lock);
	149	if (ret) {
	150	printk("sha256 digest failed\n");
	151	}
	152	return ret;
	153	}
	154	static int csum_tree_block(struct btrfs_root root, struct buffer_head bh,
	155	int verify)
	156	{
	157	char result[BTRFS_CSUM_SIZE];
	158	int ret;
	159	struct btrfs_node *node;
	160
	161	ret = btrfs_csum_data(root, bh->b_data + BTRFS_CSUM_SIZE,
	162	bh->b_size - BTRFS_CSUM_SIZE, result);
	163	if (ret)
	164	return ret;
	165	if (verify) {
	166	if (memcmp(bh->b_data, result, BTRFS_CSUM_SIZE)) {
	167	printk("checksum verify failed on %lu\n",
	168	bh->b_blocknr);
	169	return 1;
	170	}
	171	} else {
	172	node = btrfs_buffer_node(bh);
	173	memcpy(node->header.csum, result, BTRFS_CSUM_SIZE);
	174	}
	175	return 0;
	176	}
	177
	178	static int btree_writepage(struct page page, struct writeback_control wbc)
	179	{
	180	struct buffer_head *bh;
	181	struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
	182	struct buffer_head *head;
	183	if (!page_has_buffers(page)) {
	184	create_empty_buffers(page, root->fs_info->sb->s_blocksize,
	185	(1 << BH_Dirty)\|(1 << BH_Uptodate));
	186	}
	187	head = page_buffers(page);
	188	bh = head;
	189	do {
	190	if (buffer_dirty(bh))
	191	csum_tree_block(root, bh, 0);
	192	bh = bh->b_this_page;
	193	} while (bh != head);
	194	return block_write_full_page(page, btree_get_block, wbc);
	195	}
	196
	197	static int btree_readpage(struct file * file, struct page * page)
	198	{
	199	return block_read_full_page(page, btree_get_block);
	200	}
	201
	202	static struct address_space_operations btree_aops = {
	203	.readpage = btree_readpage,
	204	.writepage = btree_writepage,
	205	.sync_page = block_sync_page,
	206	};
	207
	208	struct buffer_head read_tree_block(struct btrfs_root root, u64 blocknr)
	209	{
	210	struct buffer_head *bh = NULL;
	211
	212	bh = btrfs_find_create_tree_block(root, blocknr);
	213	if (!bh)
	214	return bh;
	215	if (buffer_uptodate(bh))
	216	goto uptodate;
	217	lock_buffer(bh);
	218	if (!buffer_uptodate(bh)) {
	219	get_bh(bh);
	220	bh->b_end_io = end_buffer_read_sync;
	221	submit_bh(READ, bh);
	222	wait_on_buffer(bh);
	223	if (!buffer_uptodate(bh))
	224	goto fail;
	225	csum_tree_block(root, bh, 1);
	226	} else {
	227	unlock_buffer(bh);
	228	}
	229	uptodate:
	230	if (check_tree_block(root, bh))
	231	BUG();
	232	return bh;
	233	fail:
	234	brelse(bh);
	235	return NULL;
	236	}
	237
	238	int dirty_tree_block(struct btrfs_trans_handle trans, struct btrfs_root root,
	239	struct buffer_head *buf)
	240	{
	241	WARN_ON(atomic_read(&buf->b_count) == 0);
	242	mark_buffer_dirty(buf);
	243	return 0;
	244	}
	245
	246	int clean_tree_block(struct btrfs_trans_handle trans, struct btrfs_root root,
	247	struct buffer_head *buf)
	248	{
	249	WARN_ON(atomic_read(&buf->b_count) == 0);
	250	clear_buffer_dirty(buf);
	251	return 0;
	252	}
	253
	254	static int __setup_root(int blocksize,
	255	struct btrfs_root *root,
	256	struct btrfs_fs_info *fs_info,
	257	u64 objectid)
	258	{
	259	root->node = NULL;
	260	root->inode = NULL;
	261	root->commit_root = NULL;
	262	root->blocksize = blocksize;
	263	root->ref_cows = 0;
	264	root->fs_info = fs_info;
	265	root->objectid = objectid;
	266	root->last_trans = 0;
	267	root->highest_inode = 0;
	268	root->last_inode_alloc = 0;
	269	memset(&root->root_key, 0, sizeof(root->root_key));
	270	memset(&root->root_item, 0, sizeof(root->root_item));
	271	return 0;
	272	}
	273
	274	static int find_and_setup_root(int blocksize,
	275	struct btrfs_root *tree_root,
	276	struct btrfs_fs_info *fs_info,
	277	u64 objectid,
	278	struct btrfs_root *root)
	279	{
	280	int ret;
	281
	282	__setup_root(blocksize, root, fs_info, objectid);
	283	ret = btrfs_find_last_root(tree_root, objectid,
	284	&root->root_item, &root->root_key);
	285	BUG_ON(ret);
	286
	287	root->node = read_tree_block(root,
	288	btrfs_root_blocknr(&root->root_item));
	289	BUG_ON(!root->node);
	290	return 0;
	291	}
	292
	293	struct btrfs_root btrfs_read_fs_root(struct btrfs_fs_info fs_info,
	294	struct btrfs_key *location)
	295	{
	296	struct btrfs_root *root;
	297	struct btrfs_root *tree_root = fs_info->tree_root;
	298	struct btrfs_path *path;
	299	struct btrfs_leaf *l;
	300	u64 highest_inode;
	301	int ret = 0;
	302
	303	printk("read_fs_root looking for %Lu %Lu %u\n", location->objectid, location->offset, location->flags);
	304	root = radix_tree_lookup(&fs_info->fs_roots_radix,
	305	(unsigned long)location->objectid);
	306	if (root) {
	307	printk("found %p in cache\n", root);
	308	return root;
	309	}
	310	root = kmalloc(sizeof(*root), GFP_NOFS);
	311	if (!root) {
	312	printk("failed1\n");
	313	return ERR_PTR(-ENOMEM);
	314	}
	315	if (location->offset == (u64)-1) {
	316	ret = find_and_setup_root(fs_info->sb->s_blocksize,
	317	fs_info->tree_root, fs_info,
	318	location->objectid, root);
	319	if (ret) {
	320	printk("failed2\n");
	321	kfree(root);
	322	return ERR_PTR(ret);
	323	}
	324	goto insert;
	325	}
	326
	327	__setup_root(fs_info->sb->s_blocksize, root, fs_info,
	328	location->objectid);
	329
	330	path = btrfs_alloc_path();
	331	BUG_ON(!path);
	332	ret = btrfs_search_slot(NULL, tree_root, location, path, 0, 0);
	333	if (ret != 0) {
	334	printk("internal search_slot gives us %d\n", ret);
	335	if (ret > 0)
	336	ret = -ENOENT;
	337	goto out;
	338	}
	339	l = btrfs_buffer_leaf(path->nodes[0]);
	340	memcpy(&root->root_item,
	341	btrfs_item_ptr(l, path->slots[0], struct btrfs_root_item),
	342	sizeof(root->root_item));
	343	memcpy(&root->root_key, location, sizeof(*location));
	344	ret = 0;
	345	out:
	346	btrfs_release_path(root, path);
	347	btrfs_free_path(path);
	348	if (ret) {
	349	kfree(root);
	350	return ERR_PTR(ret);
	351	}
	352	root->node = read_tree_block(root,
	353	btrfs_root_blocknr(&root->root_item));
	354	BUG_ON(!root->node);
	355	insert:
	356	printk("inserting %p\n", root);
	357	root->ref_cows = 1;
	358	ret = radix_tree_insert(&fs_info->fs_roots_radix,
	359	(unsigned long)root->root_key.objectid,
	360	root);
	361	if (ret) {
	362	printk("radix_tree_insert gives us %d\n", ret);
	363	brelse(root->node);
	364	kfree(root);
	365	return ERR_PTR(ret);
	366	}
	367	ret = btrfs_find_highest_inode(root, &highest_inode);
	368	if (ret == 0) {
	369	root->highest_inode = highest_inode;
	370	root->last_inode_alloc = highest_inode;
	371	printk("highest inode is %Lu\n", highest_inode);
	372	}
	373	printk("all worked\n");
	374	return root;
	375	}
	376
	377	struct btrfs_root open_ctree(struct super_block sb)
	378	{
	379	struct btrfs_root *extent_root = kmalloc(sizeof(struct btrfs_root),
	380	GFP_NOFS);
	381	struct btrfs_root *dev_root = kmalloc(sizeof(struct btrfs_root),
	382	GFP_NOFS);
	383	struct btrfs_root *tree_root = kmalloc(sizeof(struct btrfs_root),
	384	GFP_NOFS);
	385	struct btrfs_fs_info fs_info = kmalloc(sizeof(fs_info),
	386	GFP_NOFS);
	387	int ret;
	388	struct btrfs_super_block *disk_super;
	389
	390	init_bit_radix(&fs_info->pinned_radix);
	391	init_bit_radix(&fs_info->pending_del_radix);
	392	INIT_RADIX_TREE(&fs_info->fs_roots_radix, GFP_NOFS);
	393	sb_set_blocksize(sb, 4096);
	394	fs_info->running_transaction = NULL;
	395	fs_info->tree_root = tree_root;
	396	fs_info->extent_root = extent_root;
	397	fs_info->dev_root = dev_root;
	398	fs_info->sb = sb;
	399	fs_info->btree_inode = new_inode(sb);
	400	fs_info->btree_inode->i_ino = 1;
	401	fs_info->btree_inode->i_nlink = 1;
	402	fs_info->btree_inode->i_size = sb->s_bdev->bd_inode->i_size;
	403	fs_info->btree_inode->i_mapping->a_ops = &btree_aops;
	404	BTRFS_I(fs_info->btree_inode)->root = tree_root;
	405	memset(&BTRFS_I(fs_info->btree_inode)->location, 0,
	406	sizeof(struct btrfs_key));
	407	insert_inode_hash(fs_info->btree_inode);
	408	mapping_set_gfp_mask(fs_info->btree_inode->i_mapping, GFP_NOFS);
	409	fs_info->hash_tfm = crypto_alloc_hash("sha256", 0, CRYPTO_ALG_ASYNC);
	410	spin_lock_init(&fs_info->hash_lock);
	411	if (!fs_info->hash_tfm \|\| IS_ERR(fs_info->hash_tfm)) {
	412	printk("failed to allocate sha256 hash\n");
	413	return NULL;
	414	}
	415	mutex_init(&fs_info->trans_mutex);
	416	mutex_init(&fs_info->fs_mutex);
	417	memset(&fs_info->current_insert, 0, sizeof(fs_info->current_insert));
	418	memset(&fs_info->last_insert, 0, sizeof(fs_info->last_insert));
	419
	420	__setup_root(sb->s_blocksize, dev_root,
	421	fs_info, BTRFS_DEV_TREE_OBJECTID);
	422
	423	__setup_root(sb->s_blocksize, tree_root,
	424	fs_info, BTRFS_ROOT_TREE_OBJECTID);
	425	fs_info->sb_buffer = read_tree_block(tree_root,
	426	BTRFS_SUPER_INFO_OFFSET /
	427	sb->s_blocksize);
	428
	429	if (!fs_info->sb_buffer)
	430	return NULL;
	431	disk_super = (struct btrfs_super_block *)fs_info->sb_buffer->b_data;
	432	if (!btrfs_super_root(disk_super))
	433	return NULL;
	434
	435	fs_info->disk_super = disk_super;
	436	dev_root->node = read_tree_block(tree_root,
	437	btrfs_super_device_root(disk_super));
	438	tree_root->node = read_tree_block(tree_root,
	439	btrfs_super_root(disk_super));
	440	BUG_ON(!tree_root->node);
	441
	442	mutex_lock(&fs_info->fs_mutex);
	443	ret = find_and_setup_root(sb->s_blocksize, tree_root, fs_info,
	444	BTRFS_EXTENT_TREE_OBJECTID, extent_root);
	445	BUG_ON(ret);
	446
	447	fs_info->generation = btrfs_super_generation(disk_super) + 1;
	448	memset(&fs_info->kobj, 0, sizeof(fs_info->kobj));
	449	kobj_set_kset_s(fs_info, btrfs_subsys);
	450	kobject_set_name(&fs_info->kobj, "%s", sb->s_id);
	451	kobject_register(&fs_info->kobj);
	452	mutex_unlock(&fs_info->fs_mutex);
	453	return tree_root;
	454	}
	455
	456	int write_ctree_super(struct btrfs_trans_handle *trans, struct btrfs_root
	457	*root)
	458	{
	459	struct buffer_head *bh = root->fs_info->sb_buffer;
	460
	461	btrfs_set_super_root(root->fs_info->disk_super,
	462	root->fs_info->tree_root->node->b_blocknr);
	463	lock_buffer(bh);
	464	WARN_ON(atomic_read(&bh->b_count) < 1);
	465	clear_buffer_dirty(bh);
	466	csum_tree_block(root, bh, 0);
	467	bh->b_end_io = end_buffer_write_sync;
	468	get_bh(bh);
	469	submit_bh(WRITE, bh);
	470	wait_on_buffer(bh);
	471	if (!buffer_uptodate(bh)) {
	472	WARN_ON(1);
	473	return -EIO;
	474	}
	475	return 0;
	476	}
	477
	478	static int free_fs_root(struct btrfs_fs_info fs_info, struct btrfs_root root)
	479	{
	480	radix_tree_delete(&fs_info->fs_roots_radix,
	481	(unsigned long)root->root_key.objectid);
	482	if (root->inode)
	483	iput(root->inode);
	484	if (root->node)
	485	brelse(root->node);
	486	if (root->commit_root)
	487	brelse(root->commit_root);
	488	kfree(root);
	489	return 0;
	490	}
	491
	492	int del_fs_roots(struct btrfs_fs_info *fs_info)
	493	{
	494	int ret;
	495	struct btrfs_root *gang[8];
	496	int i;
	497
	498	while(1) {
	499	ret = radix_tree_gang_lookup(&fs_info->fs_roots_radix,
	500	(void **)gang, 0,
	501	ARRAY_SIZE(gang));
	502	if (!ret)
	503	break;
	504	for (i = 0; i < ret; i++)
	505	free_fs_root(fs_info, gang[i]);
	506	}
	507	return 0;
	508	}
	509
	510	int close_ctree(struct btrfs_root *root)
	511	{
	512	int ret;
	513	struct btrfs_trans_handle *trans;
	514	struct btrfs_fs_info *fs_info = root->fs_info;
	515
	516	mutex_lock(&fs_info->fs_mutex);
	517	trans = btrfs_start_transaction(root, 1);
	518	btrfs_commit_transaction(trans, root);
	519	/* run commit again to drop the original snapshot */
	520	trans = btrfs_start_transaction(root, 1);
	521	btrfs_commit_transaction(trans, root);
	522	ret = btrfs_write_and_wait_transaction(NULL, root);
	523	BUG_ON(ret);
	524	write_ctree_super(NULL, root);
	525	mutex_unlock(&fs_info->fs_mutex);
	526
	527	if (fs_info->extent_root->node)
	528	btrfs_block_release(fs_info->extent_root,
	529	fs_info->extent_root->node);
	530	if (fs_info->dev_root->node)
	531	btrfs_block_release(fs_info->dev_root,
	532	fs_info->dev_root->node);
	533	if (fs_info->tree_root->node)
	534	btrfs_block_release(fs_info->tree_root,
	535	fs_info->tree_root->node);
	536	btrfs_block_release(root, fs_info->sb_buffer);
	537	crypto_free_hash(fs_info->hash_tfm);
	538	truncate_inode_pages(fs_info->btree_inode->i_mapping, 0);
	539	iput(fs_info->btree_inode);
	540	del_fs_roots(fs_info);
	541	kfree(fs_info->extent_root);
	542	kfree(fs_info->tree_root);
	543	kobject_unregister(&fs_info->kobj);
	544	return 0;
	545	}
	546
	547	void btrfs_block_release(struct btrfs_root root, struct buffer_head buf)
	548	{
	549	brelse(buf);
	550	}
	551