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

#include <linux/module.h>
#include <linux/fs.h>
#include <linux/blkdev.h>
#include "ctree.h"
#include "disk-io.h"
#include "transaction.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();
	}
	if (root->node && btrfs_header_parentid(&node->header) !=
	    btrfs_header_parentid(btrfs_buffer_header(root->node))) {
		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);
	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;

	wait_on_page_writeback(page);
	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);
	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;
}

static int btree_writepage(struct page *page, struct writeback_control *wbc)
{
	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;
	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);
	}
	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)
{
	mark_buffer_dirty(buf);
	return 0;
}

int clean_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
		     struct buffer_head *buf)
{
	clear_buffer_dirty(buf);
	return 0;
}

static int __setup_root(struct btrfs_super_block *super,
			struct btrfs_root *root,
			struct btrfs_fs_info *fs_info,
			u64 objectid)
{
	root->node = NULL;
	root->commit_root = NULL;
	root->blocksize = btrfs_super_blocksize(super);
	root->ref_cows = 0;
	root->fs_info = fs_info;
	memset(&root->root_key, 0, sizeof(root->root_key));
	memset(&root->root_item, 0, sizeof(root->root_item));
	return 0;
}

static int find_and_setup_root(struct btrfs_super_block *super,
			       struct btrfs_root *tree_root,
			       struct btrfs_fs_info *fs_info,
			       u64 objectid,
			       struct btrfs_root *root)
{
	int ret;

	__setup_root(super, 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 *open_ctree(struct super_block *sb,
			      struct buffer_head *sb_buffer,
			      struct btrfs_super_block *disk_super)
{
	struct btrfs_root *root = kmalloc(sizeof(struct btrfs_root),
					  GFP_NOFS);
	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_root *inode_root = kmalloc(sizeof(struct btrfs_root),
						GFP_NOFS);
	struct btrfs_fs_info *fs_info = kmalloc(sizeof(*fs_info),
						GFP_NOFS);
	int ret;

	if (!btrfs_super_root(disk_super))
		return NULL;
	init_bit_radix(&fs_info->pinned_radix);
	init_bit_radix(&fs_info->pending_del_radix);
	sb_set_blocksize(sb, sb_buffer->b_size);
	fs_info->running_transaction = NULL;
	fs_info->fs_root = root;
	fs_info->tree_root = tree_root;
	fs_info->extent_root = extent_root;
	fs_info->inode_root = inode_root;
	fs_info->last_inode_alloc = 0;
	fs_info->last_inode_alloc_dirid = 0;
	fs_info->disk_super = disk_super;
	fs_info->sb = sb;
	fs_info->btree_inode = new_inode(sb);
	fs_info->btree_inode->i_ino = 1;
	fs_info->btree_inode->i_size = sb->s_bdev->bd_inode->i_size;
	fs_info->btree_inode->i_mapping->a_ops = &btree_aops;
	mapping_set_gfp_mask(fs_info->btree_inode->i_mapping, GFP_NOFS);

	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(disk_super, tree_root, fs_info, BTRFS_ROOT_TREE_OBJECTID);

	fs_info->sb_buffer = read_tree_block(tree_root, sb_buffer->b_blocknr);

	if (!fs_info->sb_buffer)
		return NULL;

	brelse(sb_buffer);
	sb_buffer = NULL;
	disk_super = (struct btrfs_super_block *)fs_info->sb_buffer->b_data;
	fs_info->disk_super = disk_super;

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

	ret = find_and_setup_root(disk_super, tree_root, fs_info,
				  BTRFS_EXTENT_TREE_OBJECTID, extent_root);
	BUG_ON(ret);

	ret = find_and_setup_root(disk_super, tree_root, fs_info,
				  BTRFS_INODE_MAP_OBJECTID, inode_root);
	BUG_ON(ret);

	ret = find_and_setup_root(disk_super, tree_root, fs_info,
				  BTRFS_FS_TREE_OBJECTID, root);
	BUG_ON(ret);
	root->commit_root = root->node;
	get_bh(root->node);
	root->ref_cows = 1;
	root->fs_info->generation = root->root_key.offset + 1;
	return root;
}

int write_ctree_super(struct btrfs_trans_handle *trans, struct btrfs_root
		      *root)
{
	struct 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);
	clear_buffer_dirty(bh);
	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;
}

int close_ctree(struct btrfs_root *root)
{
	int ret;
	struct btrfs_trans_handle *trans;

	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);

	if (root->node)
		btrfs_block_release(root, root->node);
	if (root->fs_info->extent_root->node)
		btrfs_block_release(root->fs_info->extent_root,
				    root->fs_info->extent_root->node);
	if (root->fs_info->inode_root->node)
		btrfs_block_release(root->fs_info->inode_root,
				    root->fs_info->inode_root->node);
	if (root->fs_info->tree_root->node)
		btrfs_block_release(root->fs_info->tree_root,
				    root->fs_info->tree_root->node);
	btrfs_block_release(root, root->commit_root);
	btrfs_block_release(root, root->fs_info->sb_buffer);
	iput(root->fs_info->btree_inode);
	kfree(root->fs_info->extent_root);
	kfree(root->fs_info->inode_root);
	kfree(root->fs_info->tree_root);
	kfree(root->fs_info);
	kfree(root);
	return 0;
}

void btrfs_block_release(struct btrfs_root *root, struct buffer_head *buf)
{
	brelse(buf);
}
Commit	Line	Data
e20d96d6 CM	1	#include <linux/module.h>
e20d96d6 CM	2	#include <linux/fs.h>
d98237b3	3	#include <linux/blkdev.h>
eb60ceac CM	4	#include "ctree.h"
eb60ceac CM	5	#include "disk-io.h"
e089f05c	6	#include "transaction.h"
eb60ceac	7
d98237b3	8
e20d96d6	9	static int check_tree_block(struct btrfs_root root, struct buffer_head buf)
eb60ceac	10	{
e20d96d6	11	struct btrfs_node *node = btrfs_buffer_node(buf);
d98237b3	12	if (buf->b_blocknr != btrfs_header_blocknr(&node->header)) {
9a8dd150	13	BUG();
d98237b3	14	}
e20d96d6	15	if (root->node && btrfs_header_parentid(&node->header) !=
df2ce34c	16	btrfs_header_parentid(btrfs_buffer_header(root->node))) {
7f5c1516	17	BUG();
df2ce34c	18	}
9a8dd150	19	return 0;
eb60ceac CM	20	}
eb60ceac CM	21
d98237b3 CM	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	page = find_lock_page(mapping, index);
	33	if (!page)
	34	return NULL;
	35
	36	if (!page_has_buffers(page))
	37	goto out_unlock;
	38
	39	head = page_buffers(page);
	40	bh = head;
	41	do {
	42	if (buffer_mapped(bh) && bh->b_blocknr == blocknr) {
	43	ret = bh;
	44	get_bh(bh);
	45	goto out_unlock;
	46	}
	47	bh = bh->b_this_page;
	48	} while (bh != head);
	49	out_unlock:
	50	unlock_page(page);
	51	page_cache_release(page);
	52	return ret;
	53	}
	54
	55	struct buffer_head btrfs_find_create_tree_block(struct btrfs_root root,
	56	u64 blocknr)
	57	{
	58	struct address_space *mapping = root->fs_info->btree_inode->i_mapping;
	59	int blockbits = root->fs_info->sb->s_blocksize_bits;
	60	unsigned long index = blocknr >> (PAGE_CACHE_SHIFT - blockbits);
	61	struct page *page;
	62	struct buffer_head *bh;
	63	struct buffer_head *head;
	64	struct buffer_head *ret = NULL;
	65	u64 first_block = index << (PAGE_CACHE_SHIFT - blockbits);
	66	page = grab_cache_page(mapping, index);
	67	if (!page)
	68	return NULL;
	69
	70	wait_on_page_writeback(page);
	71	if (!page_has_buffers(page))
	72	create_empty_buffers(page, root->fs_info->sb->s_blocksize, 0);
	73	head = page_buffers(page);
	74	bh = head;
	75	do {
	76	if (!buffer_mapped(bh)) {
	77	bh->b_bdev = root->fs_info->sb->s_bdev;
	78	bh->b_blocknr = first_block;
	79	set_buffer_mapped(bh);
	80	}
	81	if (bh->b_blocknr == blocknr) {
	82	ret = bh;
	83	get_bh(bh);
	84	goto out_unlock;
	85	}
86	bh = bh->b_this_page;
87	first_block++;
88	} while (bh != head);
89	out_unlock:
90	unlock_page(page);
91	page_cache_release(page);
92	return ret;
93	}
94
95	static sector_t max_block(struct block_device *bdev)
96	{
97	sector_t retval = ~((sector_t)0);
98	loff_t sz = i_size_read(bdev->bd_inode);
99
100	if (sz) {
101	unsigned int size = block_size(bdev);
102	unsigned int sizebits = blksize_bits(size);
103	retval = (sz >> sizebits);
104	}
105	return retval;
106	}
107
108	static int btree_get_block(struct inode *inode, sector_t iblock,
109	struct buffer_head *bh, int create)
110	{
111	if (iblock >= max_block(inode->i_sb->s_bdev)) {
112	if (create)
113	return -EIO;
114
115	/*
116	* for reads, we're just trying to fill a partial page.
117	* return a hole, they will have to call get_block again
118	* before they can fill it, and they will get -EIO at that
119	* time
120	*/
121	return 0;
122	}
123	bh->b_bdev = inode->i_sb->s_bdev;
124	bh->b_blocknr = iblock;
125	set_buffer_mapped(bh);
126	return 0;
127	}
128
129	static int btree_writepage(struct page page, struct writeback_control wbc)
ed2ff2cb	130	{
d98237b3	131	return block_write_full_page(page, btree_get_block, wbc);
ed2ff2cb CM	132	}
ed2ff2cb CM	133
d98237b3	134	static int btree_readpage(struct file * file, struct page * page)
eb60ceac	135	{
d98237b3	136	return block_read_full_page(page, btree_get_block);
eb60ceac CM	137	}
eb60ceac CM	138
d98237b3 CM	139	static struct address_space_operations btree_aops = {
	140	.readpage = btree_readpage,
	141	.writepage = btree_writepage,
	142	.sync_page = block_sync_page,
	143	};
	144
e20d96d6	145	struct buffer_head read_tree_block(struct btrfs_root root, u64 blocknr)
eb60ceac	146	{
d98237b3	147	struct buffer_head *bh = NULL;
eb60ceac	148
d98237b3 CM	149	bh = btrfs_find_create_tree_block(root, blocknr);
	150	if (!bh)
	151	return bh;
	152	lock_buffer(bh);
	153	if (!buffer_uptodate(bh)) {
	154	get_bh(bh);
	155	bh->b_end_io = end_buffer_read_sync;
	156	submit_bh(READ, bh);
	157	wait_on_buffer(bh);
	158	if (!buffer_uptodate(bh))
	159	goto fail;
	160	} else {
	161	unlock_buffer(bh);
	162	}
	163	if (check_tree_block(root, bh))
cfaa7295	164	BUG();
d98237b3 CM	165	return bh;
	166	fail:
	167	brelse(bh);
	168	return NULL;
	169
eb60ceac CM	170	}
eb60ceac CM	171
e089f05c	172	int dirty_tree_block(struct btrfs_trans_handle trans, struct btrfs_root root,
e20d96d6	173	struct buffer_head *buf)
ed2ff2cb	174	{
e20d96d6	175	mark_buffer_dirty(buf);
ed2ff2cb CM	176	return 0;
	177	}
	178
e089f05c	179	int clean_tree_block(struct btrfs_trans_handle trans, struct btrfs_root root,
e20d96d6	180	struct buffer_head *buf)
ed2ff2cb	181	{
e20d96d6	182	clear_buffer_dirty(buf);
ed2ff2cb CM	183	return 0;
	184	}
	185
123abc88	186	static int __setup_root(struct btrfs_super_block *super,
9f5fae2f CM	187	struct btrfs_root *root,
9f5fae2f CM	188	struct btrfs_fs_info *fs_info,
e20d96d6	189	u64 objectid)
d97e63b6	190	{
cfaa7295	191	root->node = NULL;
a28ec197	192	root->commit_root = NULL;
123abc88 CM	193	root->blocksize = btrfs_super_blocksize(super);
123abc88 CM	194	root->ref_cows = 0;
9f5fae2f	195	root->fs_info = fs_info;
3768f368 CM	196	memset(&root->root_key, 0, sizeof(root->root_key));
	197	memset(&root->root_item, 0, sizeof(root->root_item));
	198	return 0;
	199	}
	200
123abc88	201	static int find_and_setup_root(struct btrfs_super_block *super,
9f5fae2f CM	202	struct btrfs_root *tree_root,
	203	struct btrfs_fs_info *fs_info,
	204	u64 objectid,
e20d96d6	205	struct btrfs_root *root)
3768f368 CM	206	{
	207	int ret;
	208
e20d96d6	209	__setup_root(super, root, fs_info, objectid);
3768f368 CM	210	ret = btrfs_find_last_root(tree_root, objectid,
	211	&root->root_item, &root->root_key);
	212	BUG_ON(ret);
	213
	214	root->node = read_tree_block(root,
	215	btrfs_root_blocknr(&root->root_item));
3768f368	216	BUG_ON(!root->node);
d97e63b6 CM	217	return 0;
	218	}
	219
e20d96d6 CM	220	struct btrfs_root open_ctree(struct super_block sb,
	221	struct buffer_head *sb_buffer,
	222	struct btrfs_super_block *disk_super)
2e635a27	223	{
e20d96d6 CM	224	struct btrfs_root *root = kmalloc(sizeof(struct btrfs_root),
	225	GFP_NOFS);
	226	struct btrfs_root *extent_root = kmalloc(sizeof(struct btrfs_root),
	227	GFP_NOFS);
	228	struct btrfs_root *tree_root = kmalloc(sizeof(struct btrfs_root),
	229	GFP_NOFS);
	230	struct btrfs_root *inode_root = kmalloc(sizeof(struct btrfs_root),
	231	GFP_NOFS);
	232	struct btrfs_fs_info fs_info = kmalloc(sizeof(fs_info),
	233	GFP_NOFS);
eb60ceac CM	234	int ret;
eb60ceac CM	235
e20d96d6 CM	236	if (!btrfs_super_root(disk_super))
e20d96d6 CM	237	return NULL;
8ef97622 CM	238	init_bit_radix(&fs_info->pinned_radix);
8ef97622 CM	239	init_bit_radix(&fs_info->pending_del_radix);
d98237b3	240	sb_set_blocksize(sb, sb_buffer->b_size);
9f5fae2f CM	241	fs_info->running_transaction = NULL;
	242	fs_info->fs_root = root;
	243	fs_info->tree_root = tree_root;
	244	fs_info->extent_root = extent_root;
	245	fs_info->inode_root = inode_root;
	246	fs_info->last_inode_alloc = 0;
	247	fs_info->last_inode_alloc_dirid = 0;
e20d96d6	248	fs_info->disk_super = disk_super;
e20d96d6	249	fs_info->sb = sb;
d98237b3 CM	250	fs_info->btree_inode = new_inode(sb);
	251	fs_info->btree_inode->i_ino = 1;
	252	fs_info->btree_inode->i_size = sb->s_bdev->bd_inode->i_size;
	253	fs_info->btree_inode->i_mapping->a_ops = &btree_aops;
	254	mapping_set_gfp_mask(fs_info->btree_inode->i_mapping, GFP_NOFS);
	255
79154b1b	256	mutex_init(&fs_info->trans_mutex);
d561c025	257	mutex_init(&fs_info->fs_mutex);
9f5fae2f CM	258	memset(&fs_info->current_insert, 0, sizeof(fs_info->current_insert));
9f5fae2f CM	259	memset(&fs_info->last_insert, 0, sizeof(fs_info->last_insert));
3768f368	260
e20d96d6	261	__setup_root(disk_super, tree_root, fs_info, BTRFS_ROOT_TREE_OBJECTID);
d98237b3 CM	262
	263	fs_info->sb_buffer = read_tree_block(tree_root, sb_buffer->b_blocknr);
	264
	265	if (!fs_info->sb_buffer)
	266	return NULL;
	267
	268	brelse(sb_buffer);
	269	sb_buffer = NULL;
	270	disk_super = (struct btrfs_super_block *)fs_info->sb_buffer->b_data;
	271	fs_info->disk_super = disk_super;
	272
e20d96d6 CM	273	tree_root->node = read_tree_block(tree_root,
e20d96d6 CM	274	btrfs_super_root(disk_super));
3768f368 CM	275	BUG_ON(!tree_root->node);
3768f368 CM	276
e20d96d6 CM	277	ret = find_and_setup_root(disk_super, tree_root, fs_info,
e20d96d6 CM	278	BTRFS_EXTENT_TREE_OBJECTID, extent_root);
3768f368 CM	279	BUG_ON(ret);
3768f368 CM	280
e20d96d6 CM	281	ret = find_and_setup_root(disk_super, tree_root, fs_info,
e20d96d6 CM	282	BTRFS_INODE_MAP_OBJECTID, inode_root);
9f5fae2f CM	283	BUG_ON(ret);
9f5fae2f CM	284
e20d96d6 CM	285	ret = find_and_setup_root(disk_super, tree_root, fs_info,
e20d96d6 CM	286	BTRFS_FS_TREE_OBJECTID, root);
3768f368	287	BUG_ON(ret);
a28ec197	288	root->commit_root = root->node;
e20d96d6	289	get_bh(root->node);
3768f368	290	root->ref_cows = 1;
293ffd5f	291	root->fs_info->generation = root->root_key.offset + 1;
eb60ceac CM	292	return root;
	293	}
	294
e089f05c	295	int write_ctree_super(struct btrfs_trans_handle *trans, struct btrfs_root
79154b1b	296	*root)
eb60ceac	297	{
d5719762 CM	298	struct buffer_head *bh = root->fs_info->sb_buffer;
	299	btrfs_set_super_root(root->fs_info->disk_super,
	300	root->fs_info->tree_root->node->b_blocknr);
	301	lock_buffer(bh);
	302	clear_buffer_dirty(bh);
	303	bh->b_end_io = end_buffer_write_sync;
	304	get_bh(bh);
	305	submit_bh(WRITE, bh);
	306	wait_on_buffer(bh);
	307	if (!buffer_uptodate(bh)) {
	308	WARN_ON(1);
	309	return -EIO;
cfaa7295 CM	310	}
	311	return 0;
	312	}
	313
e20d96d6	314	int close_ctree(struct btrfs_root *root)
cfaa7295	315	{
3768f368	316	int ret;
e089f05c CM	317	struct btrfs_trans_handle *trans;
e089f05c CM	318
79154b1b CM	319	trans = btrfs_start_transaction(root, 1);
	320	btrfs_commit_transaction(trans, root);
	321	/* run commit again to drop the original snapshot */
	322	trans = btrfs_start_transaction(root, 1);
	323	btrfs_commit_transaction(trans, root);
	324	ret = btrfs_write_and_wait_transaction(NULL, root);
3768f368	325	BUG_ON(ret);
79154b1b	326	write_ctree_super(NULL, root);
ed2ff2cb	327
cfaa7295	328	if (root->node)
234b63a0	329	btrfs_block_release(root, root->node);
9f5fae2f CM	330	if (root->fs_info->extent_root->node)
	331	btrfs_block_release(root->fs_info->extent_root,
	332	root->fs_info->extent_root->node);
	333	if (root->fs_info->inode_root->node)
	334	btrfs_block_release(root->fs_info->inode_root,
	335	root->fs_info->inode_root->node);
	336	if (root->fs_info->tree_root->node)
	337	btrfs_block_release(root->fs_info->tree_root,
	338	root->fs_info->tree_root->node);
234b63a0	339	btrfs_block_release(root, root->commit_root);
e20d96d6	340	btrfs_block_release(root, root->fs_info->sb_buffer);
d98237b3	341	iput(root->fs_info->btree_inode);
e20d96d6 CM	342	kfree(root->fs_info->extent_root);
	343	kfree(root->fs_info->inode_root);
	344	kfree(root->fs_info->tree_root);
	345	kfree(root->fs_info);
	346	kfree(root);
eb60ceac CM	347	return 0;
	348	}
	349
e20d96d6	350	void btrfs_block_release(struct btrfs_root root, struct buffer_head buf)
eb60ceac	351	{
e20d96d6	352	brelse(buf);
eb60ceac CM	353	}
eb60ceac CM	354