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

/*
 * Copyright (C) 2007 Oracle.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License v2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 021110-1307, USA.
 */

#include <linux/module.h>
#include <linux/fs.h>
#include <linux/blkdev.h>
#include <linux/crc32c.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 %llu, header is %llu\n",
		       (unsigned long long)bh_blocknr(buf),
		       (unsigned long long)btrfs_header_blocknr(&node->header));
		return 1;
	}
	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 = find_or_create_page(mapping, index, GFP_NOFS);
	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)
{
	u32 crc;
	crc = crc32c(0, data, len);
	memcpy(result, &crc, BTRFS_CRC32_SIZE);
	return 0;
}

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("btrfs: %s checksum verify failed on %llu\n",
			       root->fs_info->sb->s_id,
			       (unsigned long long)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))
		goto fail;
	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_no_radix(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 = kzalloc(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 = 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 *btrfs_read_fs_root(struct btrfs_fs_info *fs_info,
				      struct btrfs_key *location)
{
	struct btrfs_root *root;
	int ret;

	root = radix_tree_lookup(&fs_info->fs_roots_radix,
				 (unsigned long)location->objectid);
	if (root)
		return root;

	root = btrfs_read_fs_root_no_radix(fs_info, location);
	if (IS_ERR(root))
		return root;
	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);
	}
	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;
	int err = -EIO;
	struct btrfs_super_block *disk_super;

	if (!extent_root || !tree_root || !fs_info) {
		err = -ENOMEM;
		goto fail;
	}
	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);

	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)
		goto fail_iput;
	disk_super = (struct btrfs_super_block *)fs_info->sb_buffer->b_data;
	fs_info->disk_super = disk_super;
	memcpy(&fs_info->super_copy, disk_super, sizeof(fs_info->super_copy));

	if (!btrfs_super_root(disk_super))
		goto fail_sb_buffer;

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


	if (strncmp((char *)(&disk_super->magic), BTRFS_MAGIC,
		    sizeof(disk_super->magic))) {
		printk("btrfs: valid FS not found on %s\n", sb->s_id);
		goto fail_sb_buffer;
	}
	tree_root->node = read_tree_block(tree_root,
					  btrfs_super_root(disk_super));
	if (!tree_root->node)
		goto fail_sb_buffer;

	mutex_lock(&fs_info->fs_mutex);
	ret = find_and_setup_root(sb->s_blocksize, tree_root, fs_info,
				  BTRFS_EXTENT_TREE_OBJECTID, extent_root);
	if (ret) {
		mutex_unlock(&fs_info->fs_mutex);
		goto fail_tree_root;
	}

	btrfs_read_block_groups(extent_root);

	fs_info->generation = btrfs_super_generation(disk_super) + 1;
	ret = btrfs_find_dead_roots(tree_root);
	if (ret)
		goto fail_tree_root;
	mutex_unlock(&fs_info->fs_mutex);
	return tree_root;

fail_tree_root:
	btrfs_block_release(tree_root, tree_root->node);
fail_sb_buffer:
	btrfs_block_release(tree_root, fs_info->sb_buffer);
fail_iput:
	iput(fs_info->btree_inode);
fail:
	kfree(extent_root);
	kfree(tree_root);
	kfree(fs_info);
	return ERR_PTR(err);
}

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

	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) {
		get_bh(bh);
		lock_buffer(bh);
		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;
}

int btrfs_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++)
			btrfs_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);
	ret = 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);
	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
6cbd5570 CM	1	/*
	2	* Copyright (C) 2007 Oracle. All rights reserved.
	3	*
	4	* This program is free software; you can redistribute it and/or
	5	* modify it under the terms of the GNU General Public
	6	* License v2 as published by the Free Software Foundation.
	7	*
	8	* This program is distributed in the hope that it will be useful,
	9	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	10	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	11	* General Public License for more details.
	12	*
	13	* You should have received a copy of the GNU General Public
	14	* License along with this program; if not, write to the
	15	* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
	16	* Boston, MA 021110-1307, USA.
	17	*/
	18
e20d96d6 CM	19	#include <linux/module.h>
e20d96d6 CM	20	#include <linux/fs.h>
d98237b3	21	#include <linux/blkdev.h>
11bd143f	22	#include <linux/crc32c.h>
87cbda5c	23	#include <linux/scatterlist.h>
22b0ebda	24	#include <linux/swap.h>
0f7d52f4	25	#include <linux/radix-tree.h>
35b7e476	26	#include <linux/writeback.h>
eb60ceac CM	27	#include "ctree.h"
eb60ceac CM	28	#include "disk-io.h"
e089f05c	29	#include "transaction.h"
0f7d52f4	30	#include "btrfs_inode.h"
eb60ceac	31
7eccb903 CM	32	u64 bh_blocknr(struct buffer_head *bh)
7eccb903 CM	33	{
0cf6c620	34	return bh->b_blocknr;
7eccb903 CM	35	}
7eccb903 CM	36
e20d96d6	37	static int check_tree_block(struct btrfs_root root, struct buffer_head buf)
eb60ceac	38	{
e20d96d6	39	struct btrfs_node *node = btrfs_buffer_node(buf);
7eccb903	40	if (bh_blocknr(buf) != btrfs_header_blocknr(&node->header)) {
5af3981c CM	41	printk(KERN_CRIT "bh_blocknr(buf) is %llu, header is %llu\n",
	42	(unsigned long long)bh_blocknr(buf),
	43	(unsigned long long)btrfs_header_blocknr(&node->header));
39279cc3	44	return 1;
d98237b3	45	}
9a8dd150	46	return 0;
eb60ceac CM	47	}
eb60ceac CM	48
d98237b3 CM	49	struct buffer_head btrfs_find_tree_block(struct btrfs_root root, u64 blocknr)
	50	{
	51	struct address_space *mapping = root->fs_info->btree_inode->i_mapping;
	52	int blockbits = root->fs_info->sb->s_blocksize_bits;
	53	unsigned long index = blocknr >> (PAGE_CACHE_SHIFT - blockbits);
	54	struct page *page;
	55	struct buffer_head *bh;
	56	struct buffer_head *head;
	57	struct buffer_head *ret = NULL;
	58
2c90e5d6	59
d98237b3 CM	60	page = find_lock_page(mapping, index);
	61	if (!page)
	62	return NULL;
	63
	64	if (!page_has_buffers(page))
	65	goto out_unlock;
	66
	67	head = page_buffers(page);
	68	bh = head;
	69	do {
7eccb903	70	if (buffer_mapped(bh) && bh_blocknr(bh) == blocknr) {
d98237b3 CM	71	ret = bh;
	72	get_bh(bh);
	73	goto out_unlock;
	74	}
	75	bh = bh->b_this_page;
	76	} while (bh != head);
	77	out_unlock:
	78	unlock_page(page);
	79	page_cache_release(page);
	80	return ret;
	81	}
	82
8352d8a4	83	int btrfs_map_bh_to_logical(struct btrfs_root root, struct buffer_head bh,
7eccb903 CM	84	u64 logical)
7eccb903 CM	85	{
236454df CM	86	if (logical == 0) {
	87	bh->b_bdev = NULL;
	88	bh->b_blocknr = 0;
	89	set_buffer_mapped(bh);
0cf6c620 CM	90	} else {
0cf6c620 CM	91	map_bh(bh, root->fs_info->sb, logical);
7eccb903	92	}
0cf6c620	93	return 0;
7eccb903 CM	94	}
7eccb903 CM	95
d98237b3 CM	96	struct buffer_head btrfs_find_create_tree_block(struct btrfs_root root,
	97	u64 blocknr)
	98	{
	99	struct address_space *mapping = root->fs_info->btree_inode->i_mapping;
	100	int blockbits = root->fs_info->sb->s_blocksize_bits;
	101	unsigned long index = blocknr >> (PAGE_CACHE_SHIFT - blockbits);
	102	struct page *page;
	103	struct buffer_head *bh;
	104	struct buffer_head *head;
	105	struct buffer_head *ret = NULL;
7eccb903	106	int err;
d98237b3	107	u64 first_block = index << (PAGE_CACHE_SHIFT - blockbits);
22b0ebda	108
34088780	109	page = find_or_create_page(mapping, index, GFP_NOFS);
d98237b3 CM	110	if (!page)
	111	return NULL;
	112
d98237b3 CM	113	if (!page_has_buffers(page))
	114	create_empty_buffers(page, root->fs_info->sb->s_blocksize, 0);
	115	head = page_buffers(page);
	116	bh = head;
	117	do {
	118	if (!buffer_mapped(bh)) {
8352d8a4	119	err = btrfs_map_bh_to_logical(root, bh, first_block);
7eccb903	120	BUG_ON(err);
d98237b3	121	}
7eccb903	122	if (bh_blocknr(bh) == blocknr) {
d98237b3 CM	123	ret = bh;
	124	get_bh(bh);
	125	goto out_unlock;
	126	}
	127	bh = bh->b_this_page;
	128	first_block++;
	129	} while (bh != head);
	130	out_unlock:
	131	unlock_page(page);
22b0ebda CM	132	if (ret)
22b0ebda CM	133	touch_buffer(ret);
d98237b3 CM	134	page_cache_release(page);
	135	return ret;
	136	}
	137
d98237b3 CM	138	static int btree_get_block(struct inode *inode, sector_t iblock,
	139	struct buffer_head *bh, int create)
	140	{
7eccb903 CM	141	int err;
7eccb903 CM	142	struct btrfs_root *root = BTRFS_I(bh->b_page->mapping->host)->root;
8352d8a4	143	err = btrfs_map_bh_to_logical(root, bh, iblock);
7eccb903	144	return err;
d98237b3 CM	145	}
d98237b3 CM	146
f254e52c CM	147	int btrfs_csum_data(struct btrfs_root * root, char *data, size_t len,
f254e52c CM	148	char *result)
87cbda5c	149	{
11bd143f CM	150	u32 crc;
	151	crc = crc32c(0, data, len);
	152	memcpy(result, &crc, BTRFS_CRC32_SIZE);
	153	return 0;
f254e52c	154	}
11bd143f	155
f254e52c CM	156	static int csum_tree_block(struct btrfs_root root, struct buffer_head bh,
	157	int verify)
	158	{
509659cd	159	char result[BTRFS_CRC32_SIZE];
f254e52c CM	160	int ret;
	161	struct btrfs_node *node;
	162
	163	ret = btrfs_csum_data(root, bh->b_data + BTRFS_CSUM_SIZE,
	164	bh->b_size - BTRFS_CSUM_SIZE, result);
	165	if (ret)
	166	return ret;
87cbda5c	167	if (verify) {
509659cd	168	if (memcmp(bh->b_data, result, BTRFS_CRC32_SIZE)) {
5af3981c CM	169	printk("btrfs: %s checksum verify failed on %llu\n",
	170	root->fs_info->sb->s_id,
	171	(unsigned long long)bh_blocknr(bh));
f254e52c CM	172	return 1;
	173	}
	174	} else {
	175	node = btrfs_buffer_node(bh);
509659cd	176	memcpy(node->header.csum, result, BTRFS_CRC32_SIZE);
f254e52c	177	}
87cbda5c CM	178	return 0;
	179	}
	180
d98237b3	181	static int btree_writepage(struct page page, struct writeback_control wbc)
ed2ff2cb	182	{
87cbda5c	183	struct buffer_head *bh;
0f7d52f4	184	struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
87cbda5c	185	struct buffer_head *head;
87cbda5c CM	186	if (!page_has_buffers(page)) {
	187	create_empty_buffers(page, root->fs_info->sb->s_blocksize,
	188	(1 << BH_Dirty)\|(1 << BH_Uptodate));
	189	}
	190	head = page_buffers(page);
	191	bh = head;
	192	do {
	193	if (buffer_dirty(bh))
	194	csum_tree_block(root, bh, 0);
	195	bh = bh->b_this_page;
	196	} while (bh != head);
d98237b3	197	return block_write_full_page(page, btree_get_block, wbc);
ed2ff2cb CM	198	}
ed2ff2cb CM	199
d98237b3	200	static int btree_readpage(struct file * file, struct page * page)
eb60ceac	201	{
d98237b3	202	return block_read_full_page(page, btree_get_block);
eb60ceac CM	203	}
eb60ceac CM	204
d98237b3 CM	205	static struct address_space_operations btree_aops = {
	206	.readpage = btree_readpage,
	207	.writepage = btree_writepage,
	208	.sync_page = block_sync_page,
	209	};
	210
090d1875 CM	211	int readahead_tree_block(struct btrfs_root *root, u64 blocknr)
	212	{
	213	struct buffer_head *bh = NULL;
de428b63	214	int ret = 0;
090d1875 CM	215
	216	bh = btrfs_find_create_tree_block(root, blocknr);
	217	if (!bh)
	218	return 0;
de428b63 CM	219	if (buffer_uptodate(bh)) {
de428b63 CM	220	ret = 1;
090d1875	221	goto done;
de428b63 CM	222	}
	223	if (test_set_buffer_locked(bh)) {
	224	ret = 1;
090d1875	225	goto done;
de428b63	226	}
090d1875 CM	227	if (!buffer_uptodate(bh)) {
	228	get_bh(bh);
	229	bh->b_end_io = end_buffer_read_sync;
	230	submit_bh(READ, bh);
	231	} else {
	232	unlock_buffer(bh);
de428b63	233	ret = 1;
090d1875 CM	234	}
	235	done:
	236	brelse(bh);
de428b63	237	return ret;
090d1875 CM	238	}
090d1875 CM	239
e20d96d6	240	struct buffer_head read_tree_block(struct btrfs_root root, u64 blocknr)
eb60ceac	241	{
d98237b3	242	struct buffer_head *bh = NULL;
eb60ceac	243
d98237b3 CM	244	bh = btrfs_find_create_tree_block(root, blocknr);
	245	if (!bh)
	246	return bh;
9d64272c CM	247	if (buffer_uptodate(bh))
9d64272c CM	248	goto uptodate;
d98237b3 CM	249	lock_buffer(bh);
	250	if (!buffer_uptodate(bh)) {
	251	get_bh(bh);
	252	bh->b_end_io = end_buffer_read_sync;
	253	submit_bh(READ, bh);
	254	wait_on_buffer(bh);
	255	if (!buffer_uptodate(bh))
	256	goto fail;
	257	} else {
	258	unlock_buffer(bh);
	259	}
9d64272c	260	uptodate:
090d1875 CM	261	if (!buffer_checked(bh)) {
	262	csum_tree_block(root, bh, 1);
	263	set_buffer_checked(bh);
	264	}
d98237b3	265	if (check_tree_block(root, bh))
39279cc3	266	goto fail;
d98237b3 CM	267	return bh;
	268	fail:
	269	brelse(bh);
	270	return NULL;
eb60ceac CM	271	}
eb60ceac CM	272
e089f05c	273	int dirty_tree_block(struct btrfs_trans_handle trans, struct btrfs_root root,
e20d96d6	274	struct buffer_head *buf)
ed2ff2cb	275	{
d6025579	276	WARN_ON(atomic_read(&buf->b_count) == 0);
e20d96d6	277	mark_buffer_dirty(buf);
ed2ff2cb CM	278	return 0;
	279	}
	280
e089f05c	281	int clean_tree_block(struct btrfs_trans_handle trans, struct btrfs_root root,
e20d96d6	282	struct buffer_head *buf)
ed2ff2cb	283	{
d6025579	284	WARN_ON(atomic_read(&buf->b_count) == 0);
e20d96d6	285	clear_buffer_dirty(buf);
ed2ff2cb CM	286	return 0;
	287	}
	288
2c90e5d6	289	static int __setup_root(int blocksize,
9f5fae2f CM	290	struct btrfs_root *root,
9f5fae2f CM	291	struct btrfs_fs_info *fs_info,
e20d96d6	292	u64 objectid)
d97e63b6	293	{
cfaa7295	294	root->node = NULL;
0f7d52f4	295	root->inode = NULL;
a28ec197	296	root->commit_root = NULL;
2c90e5d6	297	root->blocksize = blocksize;
123abc88	298	root->ref_cows = 0;
9f5fae2f	299	root->fs_info = fs_info;
0f7d52f4 CM	300	root->objectid = objectid;
0f7d52f4 CM	301	root->last_trans = 0;
1b05da2e CM	302	root->highest_inode = 0;
1b05da2e CM	303	root->last_inode_alloc = 0;
3768f368 CM	304	memset(&root->root_key, 0, sizeof(root->root_key));
3768f368 CM	305	memset(&root->root_item, 0, sizeof(root->root_item));
4d775673	306	root->root_key.objectid = objectid;
3768f368 CM	307	return 0;
	308	}
	309
2c90e5d6	310	static int find_and_setup_root(int blocksize,
9f5fae2f CM	311	struct btrfs_root *tree_root,
	312	struct btrfs_fs_info *fs_info,
	313	u64 objectid,
e20d96d6	314	struct btrfs_root *root)
3768f368 CM	315	{
	316	int ret;
	317
2c90e5d6	318	__setup_root(blocksize, root, fs_info, objectid);
3768f368 CM	319	ret = btrfs_find_last_root(tree_root, objectid,
	320	&root->root_item, &root->root_key);
	321	BUG_ON(ret);
	322
	323	root->node = read_tree_block(root,
	324	btrfs_root_blocknr(&root->root_item));
3768f368	325	BUG_ON(!root->node);
d97e63b6 CM	326	return 0;
	327	}
	328
5eda7b5e CM	329	struct btrfs_root btrfs_read_fs_root_no_radix(struct btrfs_fs_info fs_info,
5eda7b5e CM	330	struct btrfs_key *location)
0f7d52f4 CM	331	{
	332	struct btrfs_root *root;
	333	struct btrfs_root *tree_root = fs_info->tree_root;
	334	struct btrfs_path *path;
	335	struct btrfs_leaf *l;
1b05da2e	336	u64 highest_inode;
0f7d52f4 CM	337	int ret = 0;
0f7d52f4 CM	338
5eda7b5e	339	root = kzalloc(sizeof(*root), GFP_NOFS);
0cf6c620	340	if (!root)
0f7d52f4	341	return ERR_PTR(-ENOMEM);
0f7d52f4 CM	342	if (location->offset == (u64)-1) {
	343	ret = find_and_setup_root(fs_info->sb->s_blocksize,
	344	fs_info->tree_root, fs_info,
	345	location->objectid, root);
	346	if (ret) {
0f7d52f4 CM	347	kfree(root);
	348	return ERR_PTR(ret);
	349	}
	350	goto insert;
	351	}
	352
	353	__setup_root(fs_info->sb->s_blocksize, root, fs_info,
	354	location->objectid);
	355
	356	path = btrfs_alloc_path();
	357	BUG_ON(!path);
	358	ret = btrfs_search_slot(NULL, tree_root, location, path, 0, 0);
	359	if (ret != 0) {
0f7d52f4 CM	360	if (ret > 0)
	361	ret = -ENOENT;
	362	goto out;
	363	}
	364	l = btrfs_buffer_leaf(path->nodes[0]);
	365	memcpy(&root->root_item,
	366	btrfs_item_ptr(l, path->slots[0], struct btrfs_root_item),
	367	sizeof(root->root_item));
	368	memcpy(&root->root_key, location, sizeof(*location));
	369	ret = 0;
	370	out:
	371	btrfs_release_path(root, path);
	372	btrfs_free_path(path);
	373	if (ret) {
	374	kfree(root);
	375	return ERR_PTR(ret);
	376	}
	377	root->node = read_tree_block(root,
	378	btrfs_root_blocknr(&root->root_item));
	379	BUG_ON(!root->node);
	380	insert:
0f7d52f4	381	root->ref_cows = 1;
5eda7b5e CM	382	ret = btrfs_find_highest_inode(root, &highest_inode);
	383	if (ret == 0) {
	384	root->highest_inode = highest_inode;
	385	root->last_inode_alloc = highest_inode;
	386	}
	387	return root;
	388	}
	389
	390	struct btrfs_root btrfs_read_fs_root(struct btrfs_fs_info fs_info,
	391	struct btrfs_key *location)
	392	{
	393	struct btrfs_root *root;
	394	int ret;
	395
	396	root = radix_tree_lookup(&fs_info->fs_roots_radix,
	397	(unsigned long)location->objectid);
	398	if (root)
	399	return root;
	400
	401	root = btrfs_read_fs_root_no_radix(fs_info, location);
	402	if (IS_ERR(root))
	403	return root;
2619ba1f CM	404	ret = radix_tree_insert(&fs_info->fs_roots_radix,
2619ba1f CM	405	(unsigned long)root->root_key.objectid,
0f7d52f4 CM	406	root);
0f7d52f4 CM	407	if (ret) {
0f7d52f4 CM	408	brelse(root->node);
	409	kfree(root);
	410	return ERR_PTR(ret);
	411	}
0f7d52f4 CM	412	return root;
	413	}
	414
2c90e5d6	415	struct btrfs_root open_ctree(struct super_block sb)
2e635a27	416	{
e20d96d6 CM	417	struct btrfs_root *extent_root = kmalloc(sizeof(struct btrfs_root),
	418	GFP_NOFS);
	419	struct btrfs_root *tree_root = kmalloc(sizeof(struct btrfs_root),
	420	GFP_NOFS);
e20d96d6 CM	421	struct btrfs_fs_info fs_info = kmalloc(sizeof(fs_info),
e20d96d6 CM	422	GFP_NOFS);
eb60ceac	423	int ret;
39279cc3	424	int err = -EIO;
2c90e5d6	425	struct btrfs_super_block *disk_super;
eb60ceac	426
39279cc3 CM	427	if (!extent_root \|\| !tree_root \|\| !fs_info) {
	428	err = -ENOMEM;
	429	goto fail;
	430	}
8ef97622 CM	431	init_bit_radix(&fs_info->pinned_radix);
8ef97622 CM	432	init_bit_radix(&fs_info->pending_del_radix);
e37c9e69	433	init_bit_radix(&fs_info->extent_map_radix);
0f7d52f4	434	INIT_RADIX_TREE(&fs_info->fs_roots_radix, GFP_NOFS);
9078a3e1	435	INIT_RADIX_TREE(&fs_info->block_group_radix, GFP_KERNEL);
be744175	436	INIT_RADIX_TREE(&fs_info->block_group_data_radix, GFP_KERNEL);
8fd17795	437	INIT_LIST_HEAD(&fs_info->trans_list);
facda1e7	438	INIT_LIST_HEAD(&fs_info->dead_roots);
2c90e5d6	439	sb_set_blocksize(sb, 4096);
9f5fae2f	440	fs_info->running_transaction = NULL;
9f5fae2f CM	441	fs_info->tree_root = tree_root;
9f5fae2f CM	442	fs_info->extent_root = extent_root;
e20d96d6	443	fs_info->sb = sb;
d98237b3 CM	444	fs_info->btree_inode = new_inode(sb);
d98237b3 CM	445	fs_info->btree_inode->i_ino = 1;
2c90e5d6	446	fs_info->btree_inode->i_nlink = 1;
d98237b3 CM	447	fs_info->btree_inode->i_size = sb->s_bdev->bd_inode->i_size;
d98237b3 CM	448	fs_info->btree_inode->i_mapping->a_ops = &btree_aops;
e66f709b	449	fs_info->do_barriers = 1;
f2458e1d CM	450	fs_info->extent_tree_insert_nr = 0;
f2458e1d CM	451	fs_info->extent_tree_prealloc_nr = 0;
facda1e7 CM	452	fs_info->closing = 0;
facda1e7 CM	453
08607c1b	454	INIT_DELAYED_WORK(&fs_info->trans_work, btrfs_transaction_cleaner);
0f7d52f4 CM	455	BTRFS_I(fs_info->btree_inode)->root = tree_root;
	456	memset(&BTRFS_I(fs_info->btree_inode)->location, 0,
	457	sizeof(struct btrfs_key));
22b0ebda	458	insert_inode_hash(fs_info->btree_inode);
d98237b3	459	mapping_set_gfp_mask(fs_info->btree_inode->i_mapping, GFP_NOFS);
39279cc3	460
79154b1b	461	mutex_init(&fs_info->trans_mutex);
d561c025	462	mutex_init(&fs_info->fs_mutex);
3768f368	463
2c90e5d6 CM	464	__setup_root(sb->s_blocksize, tree_root,
2c90e5d6 CM	465	fs_info, BTRFS_ROOT_TREE_OBJECTID);
7eccb903	466
2c90e5d6 CM	467	fs_info->sb_buffer = read_tree_block(tree_root,
	468	BTRFS_SUPER_INFO_OFFSET /
	469	sb->s_blocksize);
d98237b3	470
0f7d52f4	471	if (!fs_info->sb_buffer)
39279cc3	472	goto fail_iput;
d98237b3	473	disk_super = (struct btrfs_super_block *)fs_info->sb_buffer->b_data;
4b52dff6 CM	474	fs_info->disk_super = disk_super;
4b52dff6 CM	475	memcpy(&fs_info->super_copy, disk_super, sizeof(fs_info->super_copy));
39279cc3	476
0f7d52f4	477	if (!btrfs_super_root(disk_super))
39279cc3	478	goto fail_sb_buffer;
0f7d52f4	479
8352d8a4 CM	480	i_size_write(fs_info->btree_inode,
	481	btrfs_super_total_blocks(disk_super) <<
	482	fs_info->btree_inode->i_blkbits);
	483
39279cc3 CM	484
	485	if (strncmp((char *)(&disk_super->magic), BTRFS_MAGIC,
	486	sizeof(disk_super->magic))) {
	487	printk("btrfs: valid FS not found on %s\n", sb->s_id);
	488	goto fail_sb_buffer;
	489	}
e20d96d6 CM	490	tree_root->node = read_tree_block(tree_root,
e20d96d6 CM	491	btrfs_super_root(disk_super));
39279cc3 CM	492	if (!tree_root->node)
39279cc3 CM	493	goto fail_sb_buffer;
3768f368	494
2c90e5d6 CM	495	mutex_lock(&fs_info->fs_mutex);
2c90e5d6 CM	496	ret = find_and_setup_root(sb->s_blocksize, tree_root, fs_info,
e20d96d6	497	BTRFS_EXTENT_TREE_OBJECTID, extent_root);
39279cc3 CM	498	if (ret) {
	499	mutex_unlock(&fs_info->fs_mutex);
	500	goto fail_tree_root;
	501	}
3768f368	502
9078a3e1 CM	503	btrfs_read_block_groups(extent_root);
9078a3e1 CM	504
0f7d52f4	505	fs_info->generation = btrfs_super_generation(disk_super) + 1;
5eda7b5e CM	506	ret = btrfs_find_dead_roots(tree_root);
	507	if (ret)
	508	goto fail_tree_root;
5be6f7f1	509	mutex_unlock(&fs_info->fs_mutex);
0f7d52f4	510	return tree_root;
39279cc3 CM	511
	512	fail_tree_root:
	513	btrfs_block_release(tree_root, tree_root->node);
	514	fail_sb_buffer:
	515	btrfs_block_release(tree_root, fs_info->sb_buffer);
	516	fail_iput:
	517	iput(fs_info->btree_inode);
	518	fail:
	519	kfree(extent_root);
	520	kfree(tree_root);
	521	kfree(fs_info);
	522	return ERR_PTR(err);
eb60ceac CM	523	}
eb60ceac CM	524
e089f05c	525	int write_ctree_super(struct btrfs_trans_handle *trans, struct btrfs_root
79154b1b	526	*root)
eb60ceac	527	{
e66f709b	528	int ret;
d5719762	529	struct buffer_head *bh = root->fs_info->sb_buffer;
2c90e5d6	530
d5719762	531	lock_buffer(bh);
2c90e5d6	532	WARN_ON(atomic_read(&bh->b_count) < 1);
d5719762	533	clear_buffer_dirty(bh);
87cbda5c	534	csum_tree_block(root, bh, 0);
d5719762 CM	535	bh->b_end_io = end_buffer_write_sync;
d5719762 CM	536	get_bh(bh);
e66f709b CM	537	if (root->fs_info->do_barriers)
	538	ret = submit_bh(WRITE_BARRIER, bh);
	539	else
	540	ret = submit_bh(WRITE, bh);
	541	if (ret == -EOPNOTSUPP) {
8c2383c3 CM	542	get_bh(bh);
8c2383c3 CM	543	lock_buffer(bh);
e66f709b CM	544	set_buffer_uptodate(bh);
	545	root->fs_info->do_barriers = 0;
	546	ret = submit_bh(WRITE, bh);
	547	}
d5719762 CM	548	wait_on_buffer(bh);
	549	if (!buffer_uptodate(bh)) {
	550	WARN_ON(1);
	551	return -EIO;
cfaa7295 CM	552	}
	553	return 0;
	554	}
	555
5eda7b5e	556	int btrfs_free_fs_root(struct btrfs_fs_info fs_info, struct btrfs_root root)
2619ba1f CM	557	{
	558	radix_tree_delete(&fs_info->fs_roots_radix,
	559	(unsigned long)root->root_key.objectid);
	560	if (root->inode)
	561	iput(root->inode);
	562	if (root->node)
	563	brelse(root->node);
	564	if (root->commit_root)
	565	brelse(root->commit_root);
	566	kfree(root);
	567	return 0;
	568	}
	569
35b7e476	570	static int del_fs_roots(struct btrfs_fs_info *fs_info)
0f7d52f4 CM	571	{
	572	int ret;
	573	struct btrfs_root *gang[8];
	574	int i;
	575
	576	while(1) {
	577	ret = radix_tree_gang_lookup(&fs_info->fs_roots_radix,
	578	(void **)gang, 0,
	579	ARRAY_SIZE(gang));
	580	if (!ret)
	581	break;
2619ba1f	582	for (i = 0; i < ret; i++)
5eda7b5e	583	btrfs_free_fs_root(fs_info, gang[i]);
0f7d52f4 CM	584	}
	585	return 0;
	586	}
b4100d64	587
e20d96d6	588	int close_ctree(struct btrfs_root *root)
cfaa7295	589	{
3768f368	590	int ret;
e089f05c	591	struct btrfs_trans_handle *trans;
0f7d52f4	592	struct btrfs_fs_info *fs_info = root->fs_info;
e089f05c	593
facda1e7	594	fs_info->closing = 1;
08607c1b	595	btrfs_transaction_flush_work(root);
0f7d52f4	596	mutex_lock(&fs_info->fs_mutex);
79154b1b	597	trans = btrfs_start_transaction(root, 1);
54aa1f4d	598	ret = btrfs_commit_transaction(trans, root);
79154b1b CM	599	/* run commit again to drop the original snapshot */
	600	trans = btrfs_start_transaction(root, 1);
	601	btrfs_commit_transaction(trans, root);
	602	ret = btrfs_write_and_wait_transaction(NULL, root);
3768f368	603	BUG_ON(ret);
79154b1b	604	write_ctree_super(NULL, root);
0f7d52f4 CM	605	mutex_unlock(&fs_info->fs_mutex);
	606
	607	if (fs_info->extent_root->node)
	608	btrfs_block_release(fs_info->extent_root,
	609	fs_info->extent_root->node);
0f7d52f4 CM	610	if (fs_info->tree_root->node)
	611	btrfs_block_release(fs_info->tree_root,
	612	fs_info->tree_root->node);
	613	btrfs_block_release(root, fs_info->sb_buffer);
0f7d52f4 CM	614	truncate_inode_pages(fs_info->btree_inode->i_mapping, 0);
0f7d52f4 CM	615	iput(fs_info->btree_inode);
7eccb903	616
9078a3e1	617	btrfs_free_block_groups(root->fs_info);
0f7d52f4 CM	618	del_fs_roots(fs_info);
0f7d52f4 CM	619	kfree(fs_info->extent_root);
0f7d52f4	620	kfree(fs_info->tree_root);
eb60ceac CM	621	return 0;
	622	}
	623
e20d96d6	624	void btrfs_block_release(struct btrfs_root root, struct buffer_head buf)
eb60ceac	625	{
7cfcc17e	626	brelse(buf);
eb60ceac CM	627	}
eb60ceac CM	628
35b7e476 CM	629	void btrfs_btree_balance_dirty(struct btrfs_root *root)
	630	{
	631	balance_dirty_pages_ratelimited(root->fs_info->btree_inode->i_mapping);
	632	}