[net-next-2.6.git] / fs / btrfs / root-tree.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 "ctree.h"
#include "transaction.h"
#include "disk-io.h"
#include "print-tree.h"

/*
 *  search forward for a root, starting with objectid 'search_start'
 *  if a root key is found, the objectid we find is filled into 'found_objectid'
 *  and 0 is returned.  < 0 is returned on error, 1 if there is nothing
 *  left in the tree.
 */
int btrfs_search_root(struct btrfs_root *root, u64 search_start,
		      u64 *found_objectid)
{
	struct btrfs_path *path;
	struct btrfs_key search_key;
	int ret;

	root = root->fs_info->tree_root;
	search_key.objectid = search_start;
	search_key.type = (u8)-1;
	search_key.offset = (u64)-1;

	path = btrfs_alloc_path();
	BUG_ON(!path);
again:
	ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0);
	if (ret < 0)
		goto out;
	if (ret == 0) {
		ret = 1;
		goto out;
	}
	if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) {
		ret = btrfs_next_leaf(root, path);
		if (ret)
			goto out;
	}
	btrfs_item_key_to_cpu(path->nodes[0], &search_key, path->slots[0]);
	if (search_key.type != BTRFS_ROOT_ITEM_KEY) {
		search_key.offset++;
		btrfs_release_path(root, path);
		goto again;
	}
	ret = 0;
	*found_objectid = search_key.objectid;

out:
	btrfs_free_path(path);
	return ret;
}

/*
 * lookup the root with the highest offset for a given objectid.  The key we do
 * find is copied into 'key'.  If we find something return 0, otherwise 1, < 0
 * on error.
 */
int btrfs_find_last_root(struct btrfs_root *root, u64 objectid,
			struct btrfs_root_item *item, struct btrfs_key *key)
{
	struct btrfs_path *path;
	struct btrfs_key search_key;
	struct btrfs_key found_key;
	struct extent_buffer *l;
	int ret;
	int slot;

	search_key.objectid = objectid;
	search_key.type = BTRFS_ROOT_ITEM_KEY;
	search_key.offset = (u64)-1;

	path = btrfs_alloc_path();
	BUG_ON(!path);
	ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0);
	if (ret < 0)
		goto out;

	BUG_ON(ret == 0);
	if (path->slots[0] == 0) {
		ret = 1;
		goto out;
	}
	l = path->nodes[0];
	slot = path->slots[0] - 1;
	btrfs_item_key_to_cpu(l, &found_key, slot);
	if (found_key.objectid != objectid ||
	    found_key.type != BTRFS_ROOT_ITEM_KEY) {
		ret = 1;
		goto out;
	}
	if (item)
		read_extent_buffer(l, item, btrfs_item_ptr_offset(l, slot),
				   sizeof(*item));
	if (key)
		memcpy(key, &found_key, sizeof(found_key));
	ret = 0;
out:
	btrfs_free_path(path);
	return ret;
}

int btrfs_set_root_node(struct btrfs_root_item *item,
			struct extent_buffer *node)
{
	btrfs_set_root_bytenr(item, node->start);
	btrfs_set_root_level(item, btrfs_header_level(node));
	btrfs_set_root_generation(item, btrfs_header_generation(node));
	return 0;
}

/*
 * copy the data in 'item' into the btree
 */
int btrfs_update_root(struct btrfs_trans_handle *trans, struct btrfs_root
		      *root, struct btrfs_key *key, struct btrfs_root_item
		      *item)
{
	struct btrfs_path *path;
	struct extent_buffer *l;
	int ret;
	int slot;
	unsigned long ptr;

	path = btrfs_alloc_path();
	BUG_ON(!path);
	ret = btrfs_search_slot(trans, root, key, path, 0, 1);
	if (ret < 0)
		goto out;

	if (ret != 0) {
		btrfs_print_leaf(root, path->nodes[0]);
		printk(KERN_CRIT "unable to update root key %llu %u %llu\n",
		       (unsigned long long)key->objectid, key->type,
		       (unsigned long long)key->offset);
		BUG_ON(1);
	}

	l = path->nodes[0];
	slot = path->slots[0];
	ptr = btrfs_item_ptr_offset(l, slot);
	write_extent_buffer(l, item, ptr, sizeof(*item));
	btrfs_mark_buffer_dirty(path->nodes[0]);
out:
	btrfs_free_path(path);
	return ret;
}

int btrfs_insert_root(struct btrfs_trans_handle *trans, struct btrfs_root
		      *root, struct btrfs_key *key, struct btrfs_root_item
		      *item)
{
	int ret;
	ret = btrfs_insert_item(trans, root, key, item, sizeof(*item));
	return ret;
}

/*
 * at mount time we want to find all the old transaction snapshots that were in
 * the process of being deleted if we crashed.  This is any root item with an
 * offset lower than the latest root.  They need to be queued for deletion to
 * finish what was happening when we crashed.
 */
int btrfs_find_dead_roots(struct btrfs_root *root, u64 objectid)
{
	struct btrfs_root *dead_root;
	struct btrfs_item *item;
	struct btrfs_root_item *ri;
	struct btrfs_key key;
	struct btrfs_key found_key;
	struct btrfs_path *path;
	int ret;
	u32 nritems;
	struct extent_buffer *leaf;
	int slot;

	key.objectid = objectid;
	btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
	key.offset = 0;
	path = btrfs_alloc_path();
	if (!path)
		return -ENOMEM;

again:
	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
	if (ret < 0)
		goto err;
	while (1) {
		leaf = path->nodes[0];
		nritems = btrfs_header_nritems(leaf);
		slot = path->slots[0];
		if (slot >= nritems) {
			ret = btrfs_next_leaf(root, path);
			if (ret)
				break;
			leaf = path->nodes[0];
			nritems = btrfs_header_nritems(leaf);
			slot = path->slots[0];
		}
		item = btrfs_item_nr(leaf, slot);
		btrfs_item_key_to_cpu(leaf, &key, slot);
		if (btrfs_key_type(&key) != BTRFS_ROOT_ITEM_KEY)
			goto next;

		if (key.objectid < objectid)
			goto next;

		if (key.objectid > objectid)
			break;

		ri = btrfs_item_ptr(leaf, slot, struct btrfs_root_item);
		if (btrfs_disk_root_refs(leaf, ri) != 0)
			goto next;

		memcpy(&found_key, &key, sizeof(key));
		key.offset++;
		btrfs_release_path(root, path);
		dead_root =
			btrfs_read_fs_root_no_radix(root->fs_info->tree_root,
						    &found_key);
		if (IS_ERR(dead_root)) {
			ret = PTR_ERR(dead_root);
			goto err;
		}

		ret = btrfs_add_dead_root(dead_root);
		if (ret)
			goto err;
		goto again;
next:
		slot++;
		path->slots[0]++;
	}
	ret = 0;
err:
	btrfs_free_path(path);
	return ret;
}

int btrfs_find_orphan_roots(struct btrfs_root *tree_root)
{
	struct extent_buffer *leaf;
	struct btrfs_path *path;
	struct btrfs_key key;
	struct btrfs_key root_key;
	struct btrfs_root *root;
	int err = 0;
	int ret;

	path = btrfs_alloc_path();
	if (!path)
		return -ENOMEM;

	key.objectid = BTRFS_ORPHAN_OBJECTID;
	key.type = BTRFS_ORPHAN_ITEM_KEY;
	key.offset = 0;

	root_key.type = BTRFS_ROOT_ITEM_KEY;
	root_key.offset = (u64)-1;

	while (1) {
		ret = btrfs_search_slot(NULL, tree_root, &key, path, 0, 0);
		if (ret < 0) {
			err = ret;
			break;
		}

		leaf = path->nodes[0];
		if (path->slots[0] >= btrfs_header_nritems(leaf)) {
			ret = btrfs_next_leaf(tree_root, path);
			if (ret < 0)
				err = ret;
			if (ret != 0)
				break;
			leaf = path->nodes[0];
		}

		btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
		btrfs_release_path(tree_root, path);

		if (key.objectid != BTRFS_ORPHAN_OBJECTID ||
		    key.type != BTRFS_ORPHAN_ITEM_KEY)
			break;

		root_key.objectid = key.offset;
		key.offset++;

		root = btrfs_read_fs_root_no_name(tree_root->fs_info,
						  &root_key);
		if (!IS_ERR(root))
			continue;

		ret = PTR_ERR(root);
		if (ret != -ENOENT) {
			err = ret;
			break;
		}

		ret = btrfs_find_dead_roots(tree_root, root_key.objectid);
		if (ret) {
			err = ret;
			break;
		}
	}

	btrfs_free_path(path);
	return err;
}

/* drop the root item for 'key' from 'root' */
int btrfs_del_root(struct btrfs_trans_handle *trans, struct btrfs_root *root,
		   struct btrfs_key *key)
{
	struct btrfs_path *path;
	int ret;
	struct btrfs_root_item *ri;
	struct extent_buffer *leaf;

	path = btrfs_alloc_path();
	BUG_ON(!path);
	ret = btrfs_search_slot(trans, root, key, path, -1, 1);
	if (ret < 0)
		goto out;

	BUG_ON(ret != 0);
	leaf = path->nodes[0];
	ri = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_item);

	ret = btrfs_del_item(trans, root, path);
out:
	btrfs_free_path(path);
	return ret;
}

int btrfs_del_root_ref(struct btrfs_trans_handle *trans,
		       struct btrfs_root *tree_root,
		       u64 root_id, u64 ref_id, u64 dirid, u64 *sequence,
		       const char *name, int name_len)

{
	struct btrfs_path *path;
	struct btrfs_root_ref *ref;
	struct extent_buffer *leaf;
	struct btrfs_key key;
	unsigned long ptr;
	int err = 0;
	int ret;

	path = btrfs_alloc_path();
	if (!path)
		return -ENOMEM;

	key.objectid = root_id;
	key.type = BTRFS_ROOT_BACKREF_KEY;
	key.offset = ref_id;
again:
	ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
	BUG_ON(ret < 0);
	if (ret == 0) {
		leaf = path->nodes[0];
		ref = btrfs_item_ptr(leaf, path->slots[0],
				     struct btrfs_root_ref);

		WARN_ON(btrfs_root_ref_dirid(leaf, ref) != dirid);
		WARN_ON(btrfs_root_ref_name_len(leaf, ref) != name_len);
		ptr = (unsigned long)(ref + 1);
		WARN_ON(memcmp_extent_buffer(leaf, name, ptr, name_len));
		*sequence = btrfs_root_ref_sequence(leaf, ref);

		ret = btrfs_del_item(trans, tree_root, path);
		BUG_ON(ret);
	} else
		err = -ENOENT;

	if (key.type == BTRFS_ROOT_BACKREF_KEY) {
		btrfs_release_path(tree_root, path);
		key.objectid = ref_id;
		key.type = BTRFS_ROOT_REF_KEY;
		key.offset = root_id;
		goto again;
	}

	btrfs_free_path(path);
	return err;
}

int btrfs_find_root_ref(struct btrfs_root *tree_root,
		   struct btrfs_path *path,
		   u64 root_id, u64 ref_id)
{
	struct btrfs_key key;
	int ret;

	key.objectid = root_id;
	key.type = BTRFS_ROOT_REF_KEY;
	key.offset = ref_id;

	ret = btrfs_search_slot(NULL, tree_root, &key, path, 0, 0);
	return ret;
}

/*
 * add a btrfs_root_ref item.  type is either BTRFS_ROOT_REF_KEY
 * or BTRFS_ROOT_BACKREF_KEY.
 *
 * The dirid, sequence, name and name_len refer to the directory entry
 * that is referencing the root.
 *
 * For a forward ref, the root_id is the id of the tree referencing
 * the root and ref_id is the id of the subvol  or snapshot.
 *
 * For a back ref the root_id is the id of the subvol or snapshot and
 * ref_id is the id of the tree referencing it.
 */
int btrfs_add_root_ref(struct btrfs_trans_handle *trans,
		       struct btrfs_root *tree_root,
		       u64 root_id, u64 ref_id, u64 dirid, u64 sequence,
		       const char *name, int name_len)
{
	struct btrfs_key key;
	int ret;
	struct btrfs_path *path;
	struct btrfs_root_ref *ref;
	struct extent_buffer *leaf;
	unsigned long ptr;

	path = btrfs_alloc_path();
	if (!path)
		return -ENOMEM;

	key.objectid = root_id;
	key.type = BTRFS_ROOT_BACKREF_KEY;
	key.offset = ref_id;
again:
	ret = btrfs_insert_empty_item(trans, tree_root, path, &key,
				      sizeof(*ref) + name_len);
	BUG_ON(ret);

	leaf = path->nodes[0];
	ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
	btrfs_set_root_ref_dirid(leaf, ref, dirid);
	btrfs_set_root_ref_sequence(leaf, ref, sequence);
	btrfs_set_root_ref_name_len(leaf, ref, name_len);
	ptr = (unsigned long)(ref + 1);
	write_extent_buffer(leaf, name, ptr, name_len);
	btrfs_mark_buffer_dirty(leaf);

	if (key.type == BTRFS_ROOT_BACKREF_KEY) {
		btrfs_release_path(tree_root, path);
		key.objectid = ref_id;
		key.type = BTRFS_ROOT_REF_KEY;
		key.offset = root_id;
		goto again;
	}

	btrfs_free_path(path);
	return 0;
}
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
3768f368	19	#include "ctree.h"
5eda7b5e	20	#include "transaction.h"
3768f368 CM	21	#include "disk-io.h"
	22	#include "print-tree.h"
	23
bf4ef679	24	/*
d352ac68 CM	25	* search forward for a root, starting with objectid 'search_start'
	26	* if a root key is found, the objectid we find is filled into 'found_objectid'
	27	* and 0 is returned. < 0 is returned on error, 1 if there is nothing
	28	* left in the tree.
bf4ef679 CM	29	*/
	30	int btrfs_search_root(struct btrfs_root *root, u64 search_start,
	31	u64 *found_objectid)
	32	{
	33	struct btrfs_path *path;
	34	struct btrfs_key search_key;
	35	int ret;
	36
	37	root = root->fs_info->tree_root;
	38	search_key.objectid = search_start;
	39	search_key.type = (u8)-1;
	40	search_key.offset = (u64)-1;
	41
	42	path = btrfs_alloc_path();
	43	BUG_ON(!path);
	44	again:
	45	ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0);
	46	if (ret < 0)
	47	goto out;
	48	if (ret == 0) {
	49	ret = 1;
	50	goto out;
	51	}
	52	if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) {
	53	ret = btrfs_next_leaf(root, path);
	54	if (ret)
	55	goto out;
	56	}
	57	btrfs_item_key_to_cpu(path->nodes[0], &search_key, path->slots[0]);
	58	if (search_key.type != BTRFS_ROOT_ITEM_KEY) {
	59	search_key.offset++;
	60	btrfs_release_path(root, path);
	61	goto again;
	62	}
	63	ret = 0;
	64	*found_objectid = search_key.objectid;
	65
	66	out:
	67	btrfs_free_path(path);
	68	return ret;
	69	}
	70
d352ac68 CM	71	/*
	72	* lookup the root with the highest offset for a given objectid. The key we do
	73	* find is copied into 'key'. If we find something return 0, otherwise 1, < 0
	74	* on error.
	75	*/
3768f368 CM	76	int btrfs_find_last_root(struct btrfs_root *root, u64 objectid,
	77	struct btrfs_root_item item, struct btrfs_key key)
	78	{
5caf2a00	79	struct btrfs_path *path;
3768f368	80	struct btrfs_key search_key;
5f39d397 CM	81	struct btrfs_key found_key;
5f39d397 CM	82	struct extent_buffer *l;
3768f368 CM	83	int ret;
	84	int slot;
	85
	86	search_key.objectid = objectid;
0660b5af	87	search_key.type = BTRFS_ROOT_ITEM_KEY;
5eda7b5e	88	search_key.offset = (u64)-1;
3768f368	89
5caf2a00 CM	90	path = btrfs_alloc_path();
5caf2a00 CM	91	BUG_ON(!path);
5caf2a00	92	ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0);
3768f368 CM	93	if (ret < 0)
3768f368 CM	94	goto out;
5f39d397	95
3768f368	96	BUG_ON(ret == 0);
76dda93c YZ	97	if (path->slots[0] == 0) {
	98	ret = 1;
	99	goto out;
	100	}
5f39d397	101	l = path->nodes[0];
5caf2a00	102	slot = path->slots[0] - 1;
5f39d397	103	btrfs_item_key_to_cpu(l, &found_key, slot);
76dda93c YZ	104	if (found_key.objectid != objectid \|\|
76dda93c YZ	105	found_key.type != BTRFS_ROOT_ITEM_KEY) {
3768f368 CM	106	ret = 1;
	107	goto out;
	108	}
76dda93c YZ	109	if (item)
	110	read_extent_buffer(l, item, btrfs_item_ptr_offset(l, slot),
	111	sizeof(*item));
	112	if (key)
	113	memcpy(key, &found_key, sizeof(found_key));
3768f368 CM	114	ret = 0;
3768f368 CM	115	out:
5caf2a00	116	btrfs_free_path(path);
3768f368 CM	117	return ret;
	118	}
	119
5d4f98a2 YZ	120	int btrfs_set_root_node(struct btrfs_root_item *item,
	121	struct extent_buffer *node)
	122	{
	123	btrfs_set_root_bytenr(item, node->start);
	124	btrfs_set_root_level(item, btrfs_header_level(node));
	125	btrfs_set_root_generation(item, btrfs_header_generation(node));
	126	return 0;
	127	}
	128
d352ac68 CM	129	/*
	130	* copy the data in 'item' into the btree
	131	*/
e089f05c CM	132	int btrfs_update_root(struct btrfs_trans_handle *trans, struct btrfs_root
	133	root, struct btrfs_key key, struct btrfs_root_item
	134	*item)
3768f368	135	{
5caf2a00	136	struct btrfs_path *path;
5f39d397	137	struct extent_buffer *l;
3768f368 CM	138	int ret;
3768f368 CM	139	int slot;
5f39d397	140	unsigned long ptr;
3768f368	141
5caf2a00 CM	142	path = btrfs_alloc_path();
5caf2a00 CM	143	BUG_ON(!path);
5caf2a00	144	ret = btrfs_search_slot(trans, root, key, path, 0, 1);
3768f368 CM	145	if (ret < 0)
3768f368 CM	146	goto out;
d6667462 CM	147
	148	if (ret != 0) {
	149	btrfs_print_leaf(root, path->nodes[0]);
d397712b CM	150	printk(KERN_CRIT "unable to update root key %llu %u %llu\n",
	151	(unsigned long long)key->objectid, key->type,
	152	(unsigned long long)key->offset);
d6667462 CM	153	BUG_ON(1);
	154	}
	155
5f39d397	156	l = path->nodes[0];
5caf2a00	157	slot = path->slots[0];
5f39d397 CM	158	ptr = btrfs_item_ptr_offset(l, slot);
5f39d397 CM	159	write_extent_buffer(l, item, ptr, sizeof(*item));
5caf2a00	160	btrfs_mark_buffer_dirty(path->nodes[0]);
3768f368	161	out:
5caf2a00	162	btrfs_free_path(path);
3768f368 CM	163	return ret;
	164	}
	165
e089f05c CM	166	int btrfs_insert_root(struct btrfs_trans_handle *trans, struct btrfs_root
	167	root, struct btrfs_key key, struct btrfs_root_item
	168	*item)
3768f368 CM	169	{
3768f368 CM	170	int ret;
e089f05c	171	ret = btrfs_insert_item(trans, root, key, item, sizeof(*item));
3768f368 CM	172	return ret;
	173	}
	174
d352ac68 CM	175	/*
d352ac68 CM	176	* at mount time we want to find all the old transaction snapshots that were in
d397712b CM	177	* the process of being deleted if we crashed. This is any root item with an
	178	* offset lower than the latest root. They need to be queued for deletion to
	179	* finish what was happening when we crashed.
d352ac68	180	*/
5d4f98a2	181	int btrfs_find_dead_roots(struct btrfs_root *root, u64 objectid)
5eda7b5e CM	182	{
	183	struct btrfs_root *dead_root;
	184	struct btrfs_item *item;
	185	struct btrfs_root_item *ri;
	186	struct btrfs_key key;
a7a16fd7	187	struct btrfs_key found_key;
5eda7b5e CM	188	struct btrfs_path *path;
	189	int ret;
	190	u32 nritems;
5f39d397	191	struct extent_buffer *leaf;
5eda7b5e CM	192	int slot;
5eda7b5e CM	193
5ce14bbc	194	key.objectid = objectid;
5eda7b5e CM	195	btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
	196	key.offset = 0;
	197	path = btrfs_alloc_path();
	198	if (!path)
	199	return -ENOMEM;
a7a16fd7 CM	200
a7a16fd7 CM	201	again:
5eda7b5e CM	202	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
	203	if (ret < 0)
	204	goto err;
d397712b	205	while (1) {
5f39d397 CM	206	leaf = path->nodes[0];
5f39d397 CM	207	nritems = btrfs_header_nritems(leaf);
5eda7b5e CM	208	slot = path->slots[0];
	209	if (slot >= nritems) {
	210	ret = btrfs_next_leaf(root, path);
	211	if (ret)
	212	break;
5f39d397 CM	213	leaf = path->nodes[0];
5f39d397 CM	214	nritems = btrfs_header_nritems(leaf);
5eda7b5e CM	215	slot = path->slots[0];
5eda7b5e CM	216	}
5f39d397 CM	217	item = btrfs_item_nr(leaf, slot);
5f39d397 CM	218	btrfs_item_key_to_cpu(leaf, &key, slot);
5eda7b5e CM	219	if (btrfs_key_type(&key) != BTRFS_ROOT_ITEM_KEY)
5eda7b5e CM	220	goto next;
5ce14bbc CM	221
	222	if (key.objectid < objectid)
	223	goto next;
	224
	225	if (key.objectid > objectid)
	226	break;
	227
5eda7b5e	228	ri = btrfs_item_ptr(leaf, slot, struct btrfs_root_item);
5f39d397	229	if (btrfs_disk_root_refs(leaf, ri) != 0)
5eda7b5e	230	goto next;
5ce14bbc	231
a7a16fd7 CM	232	memcpy(&found_key, &key, sizeof(key));
	233	key.offset++;
	234	btrfs_release_path(root, path);
e02119d5 CM	235	dead_root =
	236	btrfs_read_fs_root_no_radix(root->fs_info->tree_root,
	237	&found_key);
a1f39630 A	238	if (IS_ERR(dead_root)) {
a1f39630 A	239	ret = PTR_ERR(dead_root);
5eda7b5e CM	240	goto err;
5eda7b5e CM	241	}
5ce14bbc	242
5d4f98a2	243	ret = btrfs_add_dead_root(dead_root);
5eda7b5e CM	244	if (ret)
5eda7b5e CM	245	goto err;
a7a16fd7	246	goto again;
5eda7b5e CM	247	next:
	248	slot++;
	249	path->slots[0]++;
	250	}
	251	ret = 0;
	252	err:
	253	btrfs_free_path(path);
	254	return ret;
	255	}
	256
76dda93c YZ	257	int btrfs_find_orphan_roots(struct btrfs_root *tree_root)
	258	{
	259	struct extent_buffer *leaf;
	260	struct btrfs_path *path;
	261	struct btrfs_key key;
d68fc57b YZ	262	struct btrfs_key root_key;
d68fc57b YZ	263	struct btrfs_root *root;
76dda93c YZ	264	int err = 0;
	265	int ret;
	266
	267	path = btrfs_alloc_path();
	268	if (!path)
	269	return -ENOMEM;
	270
	271	key.objectid = BTRFS_ORPHAN_OBJECTID;
	272	key.type = BTRFS_ORPHAN_ITEM_KEY;
	273	key.offset = 0;
	274
d68fc57b YZ	275	root_key.type = BTRFS_ROOT_ITEM_KEY;
	276	root_key.offset = (u64)-1;
	277
76dda93c YZ	278	while (1) {
	279	ret = btrfs_search_slot(NULL, tree_root, &key, path, 0, 0);
	280	if (ret < 0) {
	281	err = ret;
	282	break;
	283	}
	284
	285	leaf = path->nodes[0];
	286	if (path->slots[0] >= btrfs_header_nritems(leaf)) {
	287	ret = btrfs_next_leaf(tree_root, path);
	288	if (ret < 0)
	289	err = ret;
	290	if (ret != 0)
	291	break;
	292	leaf = path->nodes[0];
	293	}
	294
	295	btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
	296	btrfs_release_path(tree_root, path);
	297
	298	if (key.objectid != BTRFS_ORPHAN_OBJECTID \|\|
	299	key.type != BTRFS_ORPHAN_ITEM_KEY)
	300	break;
	301
d68fc57b YZ	302	root_key.objectid = key.offset;
	303	key.offset++;
	304
	305	root = btrfs_read_fs_root_no_name(tree_root->fs_info,
	306	&root_key);
	307	if (!IS_ERR(root))
	308	continue;
	309
	310	ret = PTR_ERR(root);
	311	if (ret != -ENOENT) {
76dda93c YZ	312	err = ret;
	313	break;
	314	}
	315
d68fc57b YZ	316	ret = btrfs_find_dead_roots(tree_root, root_key.objectid);
	317	if (ret) {
	318	err = ret;
	319	break;
	320	}
76dda93c YZ	321	}
	322
	323	btrfs_free_path(path);
	324	return err;
	325	}
	326
d352ac68	327	/* drop the root item for 'key' from 'root' */
e089f05c CM	328	int btrfs_del_root(struct btrfs_trans_handle trans, struct btrfs_root root,
e089f05c CM	329	struct btrfs_key *key)
3768f368	330	{
5caf2a00	331	struct btrfs_path *path;
3768f368	332	int ret;
c5739bba	333	struct btrfs_root_item *ri;
5f39d397	334	struct extent_buffer *leaf;
3768f368	335
5caf2a00 CM	336	path = btrfs_alloc_path();
5caf2a00 CM	337	BUG_ON(!path);
5caf2a00	338	ret = btrfs_search_slot(trans, root, key, path, -1, 1);
3768f368 CM	339	if (ret < 0)
3768f368 CM	340	goto out;
edbd8d4e	341
3768f368	342	BUG_ON(ret != 0);
5f39d397 CM	343	leaf = path->nodes[0];
5f39d397 CM	344	ri = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_item);
c5739bba	345
5eda7b5e	346	ret = btrfs_del_item(trans, root, path);
3768f368	347	out:
5caf2a00	348	btrfs_free_path(path);
3768f368 CM	349	return ret;
3768f368 CM	350	}
0660b5af CM	351
	352	int btrfs_del_root_ref(struct btrfs_trans_handle *trans,
	353	struct btrfs_root *tree_root,
4df27c4d YZ	354	u64 root_id, u64 ref_id, u64 dirid, u64 *sequence,
	355	const char *name, int name_len)
	356
0660b5af	357	{
4df27c4d YZ	358	struct btrfs_path *path;
	359	struct btrfs_root_ref *ref;
	360	struct extent_buffer *leaf;
0660b5af	361	struct btrfs_key key;
4df27c4d YZ	362	unsigned long ptr;
4df27c4d YZ	363	int err = 0;
0660b5af	364	int ret;
0660b5af CM	365
0660b5af CM	366	path = btrfs_alloc_path();
4df27c4d YZ	367	if (!path)
4df27c4d YZ	368	return -ENOMEM;
0660b5af CM	369
0660b5af CM	370	key.objectid = root_id;
4df27c4d	371	key.type = BTRFS_ROOT_BACKREF_KEY;
0660b5af	372	key.offset = ref_id;
4df27c4d	373	again:
0660b5af	374	ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
4df27c4d YZ	375	BUG_ON(ret < 0);
	376	if (ret == 0) {
	377	leaf = path->nodes[0];
	378	ref = btrfs_item_ptr(leaf, path->slots[0],
	379	struct btrfs_root_ref);
	380
	381	WARN_ON(btrfs_root_ref_dirid(leaf, ref) != dirid);
	382	WARN_ON(btrfs_root_ref_name_len(leaf, ref) != name_len);
	383	ptr = (unsigned long)(ref + 1);
	384	WARN_ON(memcmp_extent_buffer(leaf, name, ptr, name_len));
	385	*sequence = btrfs_root_ref_sequence(leaf, ref);
	386
	387	ret = btrfs_del_item(trans, tree_root, path);
	388	BUG_ON(ret);
	389	} else
	390	err = -ENOENT;
	391
	392	if (key.type == BTRFS_ROOT_BACKREF_KEY) {
	393	btrfs_release_path(tree_root, path);
	394	key.objectid = ref_id;
	395	key.type = BTRFS_ROOT_REF_KEY;
	396	key.offset = root_id;
	397	goto again;
	398	}
0660b5af CM	399
0660b5af CM	400	btrfs_free_path(path);
4df27c4d	401	return err;
0660b5af CM	402	}
0660b5af CM	403
ea9e8b11 CM	404	int btrfs_find_root_ref(struct btrfs_root *tree_root,
	405	struct btrfs_path *path,
	406	u64 root_id, u64 ref_id)
	407	{
	408	struct btrfs_key key;
	409	int ret;
	410
	411	key.objectid = root_id;
	412	key.type = BTRFS_ROOT_REF_KEY;
	413	key.offset = ref_id;
	414
	415	ret = btrfs_search_slot(NULL, tree_root, &key, path, 0, 0);
	416	return ret;
	417	}
	418
0660b5af CM	419	/*
	420	* add a btrfs_root_ref item. type is either BTRFS_ROOT_REF_KEY
	421	* or BTRFS_ROOT_BACKREF_KEY.
	422	*
	423	* The dirid, sequence, name and name_len refer to the directory entry
	424	* that is referencing the root.
	425	*
	426	* For a forward ref, the root_id is the id of the tree referencing
	427	* the root and ref_id is the id of the subvol or snapshot.
	428	*
	429	* For a back ref the root_id is the id of the subvol or snapshot and
	430	* ref_id is the id of the tree referencing it.
	431	*/
	432	int btrfs_add_root_ref(struct btrfs_trans_handle *trans,
	433	struct btrfs_root *tree_root,
4df27c4d	434	u64 root_id, u64 ref_id, u64 dirid, u64 sequence,
0660b5af CM	435	const char *name, int name_len)
	436	{
	437	struct btrfs_key key;
	438	int ret;
	439	struct btrfs_path *path;
	440	struct btrfs_root_ref *ref;
	441	struct extent_buffer *leaf;
	442	unsigned long ptr;
	443
0660b5af	444	path = btrfs_alloc_path();
4df27c4d YZ	445	if (!path)
4df27c4d YZ	446	return -ENOMEM;
0660b5af CM	447
0660b5af CM	448	key.objectid = root_id;
4df27c4d	449	key.type = BTRFS_ROOT_BACKREF_KEY;
0660b5af	450	key.offset = ref_id;
4df27c4d	451	again:
0660b5af CM	452	ret = btrfs_insert_empty_item(trans, tree_root, path, &key,
	453	sizeof(*ref) + name_len);
	454	BUG_ON(ret);
	455
	456	leaf = path->nodes[0];
	457	ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
	458	btrfs_set_root_ref_dirid(leaf, ref, dirid);
	459	btrfs_set_root_ref_sequence(leaf, ref, sequence);
	460	btrfs_set_root_ref_name_len(leaf, ref, name_len);
	461	ptr = (unsigned long)(ref + 1);
	462	write_extent_buffer(leaf, name, ptr, name_len);
	463	btrfs_mark_buffer_dirty(leaf);
	464
4df27c4d YZ	465	if (key.type == BTRFS_ROOT_BACKREF_KEY) {
	466	btrfs_release_path(tree_root, path);
	467	key.objectid = ref_id;
	468	key.type = BTRFS_ROOT_REF_KEY;
	469	key.offset = root_id;
	470	goto again;
	471	}
	472
0660b5af	473	btrfs_free_path(path);
4df27c4d	474	return 0;
0660b5af	475	}