[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 <linux/writeback.h>
#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"
#include "btrfs_inode.h"

u64 bh_blocknr(struct buffer_head *bh)
{
	return bh->b_blocknr;
}

static int check_tree_block(struct btrfs_root *root, struct buffer_head *buf)
{
	struct btrfs_node *node = btrfs_buffer_node(buf);
	if (bh_blocknr(buf) != btrfs_header_blocknr(&node->header)) {
		printk(KERN_CRIT "bh_blocknr(buf) is %Lu, header is %Lu\n",
		       bh_blocknr(buf), 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_blocknr(bh) == blocknr) {
			ret = bh;
			get_bh(bh);
			goto out_unlock;
		}
		bh = bh->b_this_page;
	} while (bh != head);
out_unlock:
	unlock_page(page);
	page_cache_release(page);
	return ret;
}

int btrfs_map_bh_to_logical(struct btrfs_root *root, struct buffer_head *bh,
			     u64 logical)
{
	if (logical == 0) {
		bh->b_bdev = NULL;
		bh->b_blocknr = 0;
		set_buffer_mapped(bh);
	} else {
		map_bh(bh, root->fs_info->sb, logical);
	}
	return 0;
}

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;
	int err;
	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)) {
			err = btrfs_map_bh_to_logical(root, bh, first_block);
			BUG_ON(err);
		}
		if (bh_blocknr(bh) == 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 int btree_get_block(struct inode *inode, sector_t iblock,
			   struct buffer_head *bh, int create)
{
	int err;
	struct btrfs_root *root = BTRFS_I(bh->b_page->mapping->host)->root;
	err = btrfs_map_bh_to_logical(root, bh, iblock);
	return err;
}

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("digest failed\n");
	}
	return ret;
}
static int csum_tree_block(struct btrfs_root *root, struct buffer_head *bh,
			   int verify)
{
	char result[BTRFS_CRC32_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_CRC32_SIZE)) {
			printk("checksum verify failed on %Lu\n",
			       bh_blocknr(bh));
			return 1;
		}
	} else {
		node = btrfs_buffer_node(bh);
		memcpy(node->header.csum, result, BTRFS_CRC32_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,
};

int readahead_tree_block(struct btrfs_root *root, u64 blocknr)
{
	struct buffer_head *bh = NULL;
	int ret = 0;

	bh = btrfs_find_create_tree_block(root, blocknr);
	if (!bh)
		return 0;
	if (buffer_uptodate(bh)) {
		ret = 1;
		goto done;
	}
	if (test_set_buffer_locked(bh)) {
		ret = 1;
		goto done;
	}
	if (!buffer_uptodate(bh)) {
		get_bh(bh);
		bh->b_end_io = end_buffer_read_sync;
		submit_bh(READ, bh);
	} else {
		unlock_buffer(bh);
		ret = 1;
	}
done:
	brelse(bh);
	return ret;
}

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;
	} else {
		unlock_buffer(bh);
	}
uptodate:
	if (!buffer_checked(bh)) {
		csum_tree_block(root, bh, 1);
		set_buffer_checked(bh);
	}
	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));
	root->root_key.objectid = objectid;
	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;

	root = radix_tree_lookup(&fs_info->fs_roots_radix,
				 (unsigned long)location->objectid);
	if (root)
		return root;
	root = kmalloc(sizeof(*root), GFP_NOFS);
	if (!root)
		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) {
			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) {
		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:
	root->ref_cows = 1;
	ret = radix_tree_insert(&fs_info->fs_roots_radix,
				(unsigned long)root->root_key.objectid,
				root);
	if (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;
	}
	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 *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_bit_radix(&fs_info->extent_map_radix);
	INIT_RADIX_TREE(&fs_info->fs_roots_radix, GFP_NOFS);
	INIT_RADIX_TREE(&fs_info->block_group_radix, GFP_KERNEL);
	INIT_RADIX_TREE(&fs_info->block_group_data_radix, GFP_KERNEL);
	INIT_LIST_HEAD(&fs_info->trans_list);
	INIT_LIST_HEAD(&fs_info->dead_roots);
	sb_set_blocksize(sb, 4096);
	fs_info->running_transaction = NULL;
	fs_info->tree_root = tree_root;
	fs_info->extent_root = extent_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;
	fs_info->do_barriers = 1;
	fs_info->extent_tree_insert_nr = 0;
	fs_info->extent_tree_prealloc_nr = 0;
	fs_info->closing = 0;

	INIT_DELAYED_WORK(&fs_info->trans_work, btrfs_transaction_cleaner);
	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("crc32c", 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 digest hash\n");
		return NULL;
	}
	mutex_init(&fs_info->trans_mutex);
	mutex_init(&fs_info->fs_mutex);

	__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;

	i_size_write(fs_info->btree_inode,
		     btrfs_super_total_blocks(disk_super) <<
		     fs_info->btree_inode->i_blkbits);

	fs_info->disk_super = 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);

	btrfs_read_block_groups(extent_root);

	fs_info->generation = btrfs_super_generation(disk_super) + 1;
	mutex_unlock(&fs_info->fs_mutex);
	return tree_root;
}

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

	btrfs_set_super_root(root->fs_info->disk_super,
			     bh_blocknr(root->fs_info->tree_root->node));
	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);
	if (root->fs_info->do_barriers)
		ret = submit_bh(WRITE_BARRIER, bh);
	else
		ret = submit_bh(WRITE, bh);
	if (ret == -EOPNOTSUPP) {
		set_buffer_uptodate(bh);
		root->fs_info->do_barriers = 0;
		ret = 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;
}

static 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;

	fs_info->closing = 1;
	btrfs_transaction_flush_work(root);
	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->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);

	btrfs_free_block_groups(root->fs_info);
	del_fs_roots(fs_info);
	kfree(fs_info->extent_root);
	kfree(fs_info->tree_root);
	return 0;
}

void btrfs_block_release(struct btrfs_root *root, struct buffer_head *buf)
{
	brelse(buf);
}

void btrfs_btree_balance_dirty(struct btrfs_root *root)
{
	balance_dirty_pages_ratelimited(root->fs_info->btree_inode->i_mapping);
}
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 <linux/writeback.h>
	9	#include "ctree.h"
	10	#include "disk-io.h"
	11	#include "transaction.h"
	12	#include "btrfs_inode.h"
	13
	14	u64 bh_blocknr(struct buffer_head *bh)
	15	{
	16	return bh->b_blocknr;
	17	}
	18
	19	static int check_tree_block(struct btrfs_root root, struct buffer_head buf)
	20	{
	21	struct btrfs_node *node = btrfs_buffer_node(buf);
	22	if (bh_blocknr(buf) != btrfs_header_blocknr(&node->header)) {
	23	printk(KERN_CRIT "bh_blocknr(buf) is %Lu, header is %Lu\n",
	24	bh_blocknr(buf), btrfs_header_blocknr(&node->header));
	25	BUG();
	26	}
	27	return 0;
	28	}
	29
	30	struct buffer_head btrfs_find_tree_block(struct btrfs_root root, u64 blocknr)
	31	{
	32	struct address_space *mapping = root->fs_info->btree_inode->i_mapping;
	33	int blockbits = root->fs_info->sb->s_blocksize_bits;
	34	unsigned long index = blocknr >> (PAGE_CACHE_SHIFT - blockbits);
	35	struct page *page;
	36	struct buffer_head *bh;
	37	struct buffer_head *head;
	38	struct buffer_head *ret = NULL;
	39
	40
	41	page = find_lock_page(mapping, index);
	42	if (!page)
	43	return NULL;
	44
	45	if (!page_has_buffers(page))
	46	goto out_unlock;
	47
	48	head = page_buffers(page);
	49	bh = head;
	50	do {
	51	if (buffer_mapped(bh) && bh_blocknr(bh) == blocknr) {
	52	ret = bh;
	53	get_bh(bh);
	54	goto out_unlock;
	55	}
	56	bh = bh->b_this_page;
	57	} while (bh != head);
	58	out_unlock:
	59	unlock_page(page);
	60	page_cache_release(page);
	61	return ret;
	62	}
	63
	64	int btrfs_map_bh_to_logical(struct btrfs_root root, struct buffer_head bh,
	65	u64 logical)
	66	{
	67	if (logical == 0) {
	68	bh->b_bdev = NULL;
	69	bh->b_blocknr = 0;
	70	set_buffer_mapped(bh);
	71	} else {
	72	map_bh(bh, root->fs_info->sb, logical);
	73	}
	74	return 0;
	75	}
	76
	77	struct buffer_head btrfs_find_create_tree_block(struct btrfs_root root,
	78	u64 blocknr)
	79	{
	80	struct address_space *mapping = root->fs_info->btree_inode->i_mapping;
	81	int blockbits = root->fs_info->sb->s_blocksize_bits;
	82	unsigned long index = blocknr >> (PAGE_CACHE_SHIFT - blockbits);
	83	struct page *page;
	84	struct buffer_head *bh;
	85	struct buffer_head *head;
	86	struct buffer_head *ret = NULL;
	87	int err;
	88	u64 first_block = index << (PAGE_CACHE_SHIFT - blockbits);
	89
	90	page = grab_cache_page(mapping, index);
	91	if (!page)
	92	return NULL;
	93
	94	if (!page_has_buffers(page))
	95	create_empty_buffers(page, root->fs_info->sb->s_blocksize, 0);
	96	head = page_buffers(page);
	97	bh = head;
	98	do {
	99	if (!buffer_mapped(bh)) {
	100	err = btrfs_map_bh_to_logical(root, bh, first_block);
	101	BUG_ON(err);
	102	}
	103	if (bh_blocknr(bh) == blocknr) {
	104	ret = bh;
	105	get_bh(bh);
	106	goto out_unlock;
	107	}
	108	bh = bh->b_this_page;
	109	first_block++;
	110	} while (bh != head);
	111	out_unlock:
	112	unlock_page(page);
	113	if (ret)
	114	touch_buffer(ret);
	115	page_cache_release(page);
	116	return ret;
	117	}
	118
	119	static int btree_get_block(struct inode *inode, sector_t iblock,
	120	struct buffer_head *bh, int create)
	121	{
	122	int err;
	123	struct btrfs_root *root = BTRFS_I(bh->b_page->mapping->host)->root;
	124	err = btrfs_map_bh_to_logical(root, bh, iblock);
	125	return err;
	126	}
	127
	128	int btrfs_csum_data(struct btrfs_root * root, char *data, size_t len,
	129	char *result)
	130	{
	131	struct scatterlist sg;
	132	struct crypto_hash *tfm = root->fs_info->hash_tfm;
	133	struct hash_desc desc;
	134	int ret;
	135
	136	desc.tfm = tfm;
	137	desc.flags = 0;
	138	sg_init_one(&sg, data, len);
	139	spin_lock(&root->fs_info->hash_lock);
	140	ret = crypto_hash_digest(&desc, &sg, 1, result);
	141	spin_unlock(&root->fs_info->hash_lock);
	142	if (ret) {
	143	printk("digest failed\n");
	144	}
	145	return ret;
	146	}
	147	static int csum_tree_block(struct btrfs_root root, struct buffer_head bh,
	148	int verify)
	149	{
	150	char result[BTRFS_CRC32_SIZE];
	151	int ret;
	152	struct btrfs_node *node;
	153
	154	ret = btrfs_csum_data(root, bh->b_data + BTRFS_CSUM_SIZE,
	155	bh->b_size - BTRFS_CSUM_SIZE, result);
	156	if (ret)
	157	return ret;
	158	if (verify) {
	159	if (memcmp(bh->b_data, result, BTRFS_CRC32_SIZE)) {
	160	printk("checksum verify failed on %Lu\n",
	161	bh_blocknr(bh));
	162	return 1;
	163	}
	164	} else {
	165	node = btrfs_buffer_node(bh);
	166	memcpy(node->header.csum, result, BTRFS_CRC32_SIZE);
	167	}
	168	return 0;
	169	}
	170
	171	static int btree_writepage(struct page page, struct writeback_control wbc)
	172	{
	173	struct buffer_head *bh;
	174	struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
	175	struct buffer_head *head;
	176	if (!page_has_buffers(page)) {
	177	create_empty_buffers(page, root->fs_info->sb->s_blocksize,
	178	(1 << BH_Dirty)\|(1 << BH_Uptodate));
	179	}
	180	head = page_buffers(page);
	181	bh = head;
	182	do {
	183	if (buffer_dirty(bh))
	184	csum_tree_block(root, bh, 0);
	185	bh = bh->b_this_page;
	186	} while (bh != head);
	187	return block_write_full_page(page, btree_get_block, wbc);
	188	}
	189
	190	static int btree_readpage(struct file * file, struct page * page)
	191	{
	192	return block_read_full_page(page, btree_get_block);
	193	}
	194
	195	static struct address_space_operations btree_aops = {
	196	.readpage = btree_readpage,
	197	.writepage = btree_writepage,
	198	.sync_page = block_sync_page,
	199	};
	200
	201	int readahead_tree_block(struct btrfs_root *root, u64 blocknr)
	202	{
	203	struct buffer_head *bh = NULL;
	204	int ret = 0;
	205
	206	bh = btrfs_find_create_tree_block(root, blocknr);
	207	if (!bh)
	208	return 0;
	209	if (buffer_uptodate(bh)) {
	210	ret = 1;
	211	goto done;
	212	}
	213	if (test_set_buffer_locked(bh)) {
	214	ret = 1;
	215	goto done;
	216	}
	217	if (!buffer_uptodate(bh)) {
	218	get_bh(bh);
	219	bh->b_end_io = end_buffer_read_sync;
	220	submit_bh(READ, bh);
	221	} else {
	222	unlock_buffer(bh);
	223	ret = 1;
	224	}
	225	done:
	226	brelse(bh);
	227	return ret;
	228	}
	229
	230	struct buffer_head read_tree_block(struct btrfs_root root, u64 blocknr)
	231	{
	232	struct buffer_head *bh = NULL;
	233
	234	bh = btrfs_find_create_tree_block(root, blocknr);
	235	if (!bh)
	236	return bh;
	237	if (buffer_uptodate(bh))
	238	goto uptodate;
	239	lock_buffer(bh);
	240	if (!buffer_uptodate(bh)) {
	241	get_bh(bh);
	242	bh->b_end_io = end_buffer_read_sync;
	243	submit_bh(READ, bh);
	244	wait_on_buffer(bh);
	245	if (!buffer_uptodate(bh))
	246	goto fail;
	247	} else {
	248	unlock_buffer(bh);
	249	}
	250	uptodate:
	251	if (!buffer_checked(bh)) {
	252	csum_tree_block(root, bh, 1);
	253	set_buffer_checked(bh);
	254	}
	255	if (check_tree_block(root, bh))
	256	BUG();
	257	return bh;
	258	fail:
	259	brelse(bh);
	260	return NULL;
	261	}
	262
	263	int dirty_tree_block(struct btrfs_trans_handle trans, struct btrfs_root root,
	264	struct buffer_head *buf)
	265	{
	266	WARN_ON(atomic_read(&buf->b_count) == 0);
	267	mark_buffer_dirty(buf);
	268	return 0;
	269	}
	270
	271	int clean_tree_block(struct btrfs_trans_handle trans, struct btrfs_root root,
	272	struct buffer_head *buf)
	273	{
	274	WARN_ON(atomic_read(&buf->b_count) == 0);
	275	clear_buffer_dirty(buf);
	276	return 0;
	277	}
	278
	279	static int __setup_root(int blocksize,
	280	struct btrfs_root *root,
	281	struct btrfs_fs_info *fs_info,
	282	u64 objectid)
	283	{
	284	root->node = NULL;
	285	root->inode = NULL;
	286	root->commit_root = NULL;
	287	root->blocksize = blocksize;
	288	root->ref_cows = 0;
	289	root->fs_info = fs_info;
	290	root->objectid = objectid;
	291	root->last_trans = 0;
	292	root->highest_inode = 0;
	293	root->last_inode_alloc = 0;
	294	memset(&root->root_key, 0, sizeof(root->root_key));
	295	memset(&root->root_item, 0, sizeof(root->root_item));
	296	root->root_key.objectid = objectid;
	297	return 0;
	298	}
	299
	300	static int find_and_setup_root(int blocksize,
	301	struct btrfs_root *tree_root,
	302	struct btrfs_fs_info *fs_info,
	303	u64 objectid,
	304	struct btrfs_root *root)
	305	{
	306	int ret;
	307
	308	__setup_root(blocksize, root, fs_info, objectid);
	309	ret = btrfs_find_last_root(tree_root, objectid,
	310	&root->root_item, &root->root_key);
	311	BUG_ON(ret);
	312
	313	root->node = read_tree_block(root,
	314	btrfs_root_blocknr(&root->root_item));
	315	BUG_ON(!root->node);
	316	return 0;
	317	}
	318
	319	struct btrfs_root btrfs_read_fs_root(struct btrfs_fs_info fs_info,
	320	struct btrfs_key *location)
	321	{
	322	struct btrfs_root *root;
	323	struct btrfs_root *tree_root = fs_info->tree_root;
	324	struct btrfs_path *path;
	325	struct btrfs_leaf *l;
	326	u64 highest_inode;
	327	int ret = 0;
	328
	329	root = radix_tree_lookup(&fs_info->fs_roots_radix,
	330	(unsigned long)location->objectid);
	331	if (root)
	332	return root;
	333	root = kmalloc(sizeof(*root), GFP_NOFS);
	334	if (!root)
	335	return ERR_PTR(-ENOMEM);
	336	if (location->offset == (u64)-1) {
	337	ret = find_and_setup_root(fs_info->sb->s_blocksize,
	338	fs_info->tree_root, fs_info,
	339	location->objectid, root);
	340	if (ret) {
	341	kfree(root);
	342	return ERR_PTR(ret);
	343	}
	344	goto insert;
	345	}
	346
	347	__setup_root(fs_info->sb->s_blocksize, root, fs_info,
	348	location->objectid);
	349
	350	path = btrfs_alloc_path();
	351	BUG_ON(!path);
	352	ret = btrfs_search_slot(NULL, tree_root, location, path, 0, 0);
	353	if (ret != 0) {
	354	if (ret > 0)
	355	ret = -ENOENT;
	356	goto out;
	357	}
	358	l = btrfs_buffer_leaf(path->nodes[0]);
	359	memcpy(&root->root_item,
	360	btrfs_item_ptr(l, path->slots[0], struct btrfs_root_item),
	361	sizeof(root->root_item));
	362	memcpy(&root->root_key, location, sizeof(*location));
	363	ret = 0;
	364	out:
	365	btrfs_release_path(root, path);
	366	btrfs_free_path(path);
	367	if (ret) {
	368	kfree(root);
	369	return ERR_PTR(ret);
	370	}
	371	root->node = read_tree_block(root,
	372	btrfs_root_blocknr(&root->root_item));
	373	BUG_ON(!root->node);
	374	insert:
	375	root->ref_cows = 1;
	376	ret = radix_tree_insert(&fs_info->fs_roots_radix,
	377	(unsigned long)root->root_key.objectid,
	378	root);
	379	if (ret) {
	380	brelse(root->node);
	381	kfree(root);
	382	return ERR_PTR(ret);
	383	}
	384	ret = btrfs_find_highest_inode(root, &highest_inode);
	385	if (ret == 0) {
	386	root->highest_inode = highest_inode;
	387	root->last_inode_alloc = highest_inode;
	388	}
	389	return root;
	390	}
	391
	392	struct btrfs_root open_ctree(struct super_block sb)
	393	{
	394	struct btrfs_root *extent_root = kmalloc(sizeof(struct btrfs_root),
	395	GFP_NOFS);
	396	struct btrfs_root *tree_root = kmalloc(sizeof(struct btrfs_root),
	397	GFP_NOFS);
	398	struct btrfs_fs_info fs_info = kmalloc(sizeof(fs_info),
	399	GFP_NOFS);
	400	int ret;
	401	struct btrfs_super_block *disk_super;
	402
	403	init_bit_radix(&fs_info->pinned_radix);
	404	init_bit_radix(&fs_info->pending_del_radix);
	405	init_bit_radix(&fs_info->extent_map_radix);
	406	INIT_RADIX_TREE(&fs_info->fs_roots_radix, GFP_NOFS);
	407	INIT_RADIX_TREE(&fs_info->block_group_radix, GFP_KERNEL);
	408	INIT_RADIX_TREE(&fs_info->block_group_data_radix, GFP_KERNEL);
	409	INIT_LIST_HEAD(&fs_info->trans_list);
	410	INIT_LIST_HEAD(&fs_info->dead_roots);
	411	sb_set_blocksize(sb, 4096);
	412	fs_info->running_transaction = NULL;
	413	fs_info->tree_root = tree_root;
	414	fs_info->extent_root = extent_root;
	415	fs_info->sb = sb;
	416	fs_info->btree_inode = new_inode(sb);
	417	fs_info->btree_inode->i_ino = 1;
	418	fs_info->btree_inode->i_nlink = 1;
	419	fs_info->btree_inode->i_size = sb->s_bdev->bd_inode->i_size;
	420	fs_info->btree_inode->i_mapping->a_ops = &btree_aops;
	421	fs_info->do_barriers = 1;
	422	fs_info->extent_tree_insert_nr = 0;
	423	fs_info->extent_tree_prealloc_nr = 0;
	424	fs_info->closing = 0;
	425
	426	INIT_DELAYED_WORK(&fs_info->trans_work, btrfs_transaction_cleaner);
	427	BTRFS_I(fs_info->btree_inode)->root = tree_root;
	428	memset(&BTRFS_I(fs_info->btree_inode)->location, 0,
	429	sizeof(struct btrfs_key));
	430	insert_inode_hash(fs_info->btree_inode);
	431	mapping_set_gfp_mask(fs_info->btree_inode->i_mapping, GFP_NOFS);
	432	fs_info->hash_tfm = crypto_alloc_hash("crc32c", 0, CRYPTO_ALG_ASYNC);
	433	spin_lock_init(&fs_info->hash_lock);
	434	if (!fs_info->hash_tfm \|\| IS_ERR(fs_info->hash_tfm)) {
	435	printk("failed to allocate digest hash\n");
	436	return NULL;
	437	}
	438	mutex_init(&fs_info->trans_mutex);
	439	mutex_init(&fs_info->fs_mutex);
	440
	441	__setup_root(sb->s_blocksize, tree_root,
	442	fs_info, BTRFS_ROOT_TREE_OBJECTID);
	443
	444	fs_info->sb_buffer = read_tree_block(tree_root,
	445	BTRFS_SUPER_INFO_OFFSET /
	446	sb->s_blocksize);
	447
	448	if (!fs_info->sb_buffer)
	449	return NULL;
	450	disk_super = (struct btrfs_super_block *)fs_info->sb_buffer->b_data;
	451	if (!btrfs_super_root(disk_super))
	452	return NULL;
	453
	454	i_size_write(fs_info->btree_inode,
	455	btrfs_super_total_blocks(disk_super) <<
	456	fs_info->btree_inode->i_blkbits);
	457
	458	fs_info->disk_super = disk_super;
	459	tree_root->node = read_tree_block(tree_root,
	460	btrfs_super_root(disk_super));
	461	BUG_ON(!tree_root->node);
	462
	463	mutex_lock(&fs_info->fs_mutex);
	464	ret = find_and_setup_root(sb->s_blocksize, tree_root, fs_info,
	465	BTRFS_EXTENT_TREE_OBJECTID, extent_root);
	466	BUG_ON(ret);
	467
	468	btrfs_read_block_groups(extent_root);
	469
	470	fs_info->generation = btrfs_super_generation(disk_super) + 1;
	471	mutex_unlock(&fs_info->fs_mutex);
	472	return tree_root;
	473	}
	474
	475	int write_ctree_super(struct btrfs_trans_handle *trans, struct btrfs_root
	476	*root)
	477	{
	478	int ret;
	479	struct buffer_head *bh = root->fs_info->sb_buffer;
	480
	481	btrfs_set_super_root(root->fs_info->disk_super,
	482	bh_blocknr(root->fs_info->tree_root->node));
	483	lock_buffer(bh);
	484	WARN_ON(atomic_read(&bh->b_count) < 1);
	485	clear_buffer_dirty(bh);
	486	csum_tree_block(root, bh, 0);
	487	bh->b_end_io = end_buffer_write_sync;
	488	get_bh(bh);
	489	if (root->fs_info->do_barriers)
	490	ret = submit_bh(WRITE_BARRIER, bh);
	491	else
	492	ret = submit_bh(WRITE, bh);
	493	if (ret == -EOPNOTSUPP) {
	494	set_buffer_uptodate(bh);
	495	root->fs_info->do_barriers = 0;
	496	ret = submit_bh(WRITE, bh);
	497	}
	498	wait_on_buffer(bh);
	499	if (!buffer_uptodate(bh)) {
	500	WARN_ON(1);
	501	return -EIO;
	502	}
	503	return 0;
	504	}
	505
	506	static int free_fs_root(struct btrfs_fs_info fs_info, struct btrfs_root root)
	507	{
	508	radix_tree_delete(&fs_info->fs_roots_radix,
	509	(unsigned long)root->root_key.objectid);
	510	if (root->inode)
	511	iput(root->inode);
	512	if (root->node)
	513	brelse(root->node);
	514	if (root->commit_root)
	515	brelse(root->commit_root);
	516	kfree(root);
	517	return 0;
	518	}
	519
	520	static int del_fs_roots(struct btrfs_fs_info *fs_info)
	521	{
	522	int ret;
	523	struct btrfs_root *gang[8];
	524	int i;
	525
	526	while(1) {
	527	ret = radix_tree_gang_lookup(&fs_info->fs_roots_radix,
	528	(void **)gang, 0,
	529	ARRAY_SIZE(gang));
	530	if (!ret)
	531	break;
	532	for (i = 0; i < ret; i++)
	533	free_fs_root(fs_info, gang[i]);
	534	}
	535	return 0;
	536	}
	537
	538	int close_ctree(struct btrfs_root *root)
	539	{
	540	int ret;
	541	struct btrfs_trans_handle *trans;
	542	struct btrfs_fs_info *fs_info = root->fs_info;
	543
	544	fs_info->closing = 1;
	545	btrfs_transaction_flush_work(root);
	546	mutex_lock(&fs_info->fs_mutex);
	547	trans = btrfs_start_transaction(root, 1);
	548	btrfs_commit_transaction(trans, root);
	549	/* run commit again to drop the original snapshot */
	550	trans = btrfs_start_transaction(root, 1);
	551	btrfs_commit_transaction(trans, root);
	552	ret = btrfs_write_and_wait_transaction(NULL, root);
	553	BUG_ON(ret);
	554	write_ctree_super(NULL, root);
	555	mutex_unlock(&fs_info->fs_mutex);
	556
	557	if (fs_info->extent_root->node)
	558	btrfs_block_release(fs_info->extent_root,
	559	fs_info->extent_root->node);
	560	if (fs_info->tree_root->node)
	561	btrfs_block_release(fs_info->tree_root,
	562	fs_info->tree_root->node);
	563	btrfs_block_release(root, fs_info->sb_buffer);
	564	crypto_free_hash(fs_info->hash_tfm);
	565	truncate_inode_pages(fs_info->btree_inode->i_mapping, 0);
	566	iput(fs_info->btree_inode);
	567
	568	btrfs_free_block_groups(root->fs_info);
	569	del_fs_roots(fs_info);
	570	kfree(fs_info->extent_root);
	571	kfree(fs_info->tree_root);
	572	return 0;
	573	}
	574
	575	void btrfs_block_release(struct btrfs_root root, struct buffer_head buf)
	576	{
	577	brelse(buf);
	578	}
	579
	580	void btrfs_btree_balance_dirty(struct btrfs_root *root)
	581	{
	582	balance_dirty_pages_ratelimited(root->fs_info->btree_inode->i_mapping);
	583	}