[linux-2.6-block.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_release_path(root, path);
	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;
	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;

	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;

		ret = btrfs_find_dead_roots(tree_root, key.offset);
		if (ret) {
			err = ret;
			break;
		}

		key.offset++;
	}

	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;
	u32 refs;
	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);

	refs = btrfs_disk_root_refs(leaf, ri);
	BUG_ON(refs != 0);
	ret = btrfs_del_item(trans, root, path);
out:
	btrfs_release_path(root, path);
	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 CM	162	btrfs_release_path(root, path);
5caf2a00 CM	163	btrfs_free_path(path);
3768f368 CM	164	return ret;
	165	}
	166
e089f05c CM	167	int btrfs_insert_root(struct btrfs_trans_handle *trans, struct btrfs_root
	168	root, struct btrfs_key key, struct btrfs_root_item
	169	*item)
3768f368 CM	170	{
3768f368 CM	171	int ret;
e089f05c	172	ret = btrfs_insert_item(trans, root, key, item, sizeof(*item));
3768f368 CM	173	return ret;
	174	}
	175
d352ac68 CM	176	/*
d352ac68 CM	177	* at mount time we want to find all the old transaction snapshots that were in
d397712b CM	178	* the process of being deleted if we crashed. This is any root item with an
	179	* offset lower than the latest root. They need to be queued for deletion to
	180	* finish what was happening when we crashed.
d352ac68	181	*/
5d4f98a2	182	int btrfs_find_dead_roots(struct btrfs_root *root, u64 objectid)
5eda7b5e CM	183	{
	184	struct btrfs_root *dead_root;
	185	struct btrfs_item *item;
	186	struct btrfs_root_item *ri;
	187	struct btrfs_key key;
a7a16fd7	188	struct btrfs_key found_key;
5eda7b5e CM	189	struct btrfs_path *path;
	190	int ret;
	191	u32 nritems;
5f39d397	192	struct extent_buffer *leaf;
5eda7b5e CM	193	int slot;
5eda7b5e CM	194
5ce14bbc	195	key.objectid = objectid;
5eda7b5e CM	196	btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
	197	key.offset = 0;
	198	path = btrfs_alloc_path();
	199	if (!path)
	200	return -ENOMEM;
a7a16fd7 CM	201
a7a16fd7 CM	202	again:
5eda7b5e CM	203	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
	204	if (ret < 0)
	205	goto err;
d397712b	206	while (1) {
5f39d397 CM	207	leaf = path->nodes[0];
5f39d397 CM	208	nritems = btrfs_header_nritems(leaf);
5eda7b5e CM	209	slot = path->slots[0];
	210	if (slot >= nritems) {
	211	ret = btrfs_next_leaf(root, path);
	212	if (ret)
	213	break;
5f39d397 CM	214	leaf = path->nodes[0];
5f39d397 CM	215	nritems = btrfs_header_nritems(leaf);
5eda7b5e CM	216	slot = path->slots[0];
5eda7b5e CM	217	}
5f39d397 CM	218	item = btrfs_item_nr(leaf, slot);
5f39d397 CM	219	btrfs_item_key_to_cpu(leaf, &key, slot);
5eda7b5e CM	220	if (btrfs_key_type(&key) != BTRFS_ROOT_ITEM_KEY)
5eda7b5e CM	221	goto next;
5ce14bbc CM	222
	223	if (key.objectid < objectid)
	224	goto next;
	225
	226	if (key.objectid > objectid)
	227	break;
	228
5eda7b5e	229	ri = btrfs_item_ptr(leaf, slot, struct btrfs_root_item);
5f39d397	230	if (btrfs_disk_root_refs(leaf, ri) != 0)
5eda7b5e	231	goto next;
5ce14bbc	232
a7a16fd7 CM	233	memcpy(&found_key, &key, sizeof(key));
	234	key.offset++;
	235	btrfs_release_path(root, path);
e02119d5 CM	236	dead_root =
	237	btrfs_read_fs_root_no_radix(root->fs_info->tree_root,
	238	&found_key);
a1f39630 A	239	if (IS_ERR(dead_root)) {
a1f39630 A	240	ret = PTR_ERR(dead_root);
5eda7b5e CM	241	goto err;
5eda7b5e CM	242	}
5ce14bbc	243
5d4f98a2	244	ret = btrfs_add_dead_root(dead_root);
5eda7b5e CM	245	if (ret)
5eda7b5e CM	246	goto err;
a7a16fd7	247	goto again;
5eda7b5e CM	248	next:
	249	slot++;
	250	path->slots[0]++;
	251	}
	252	ret = 0;
	253	err:
	254	btrfs_free_path(path);
	255	return ret;
	256	}
	257
76dda93c YZ	258	int btrfs_find_orphan_roots(struct btrfs_root *tree_root)
	259	{
	260	struct extent_buffer *leaf;
	261	struct btrfs_path *path;
	262	struct btrfs_key key;
	263	int err = 0;
	264	int ret;
	265
	266	path = btrfs_alloc_path();
	267	if (!path)
	268	return -ENOMEM;
	269
	270	key.objectid = BTRFS_ORPHAN_OBJECTID;
	271	key.type = BTRFS_ORPHAN_ITEM_KEY;
	272	key.offset = 0;
	273
	274	while (1) {
	275	ret = btrfs_search_slot(NULL, tree_root, &key, path, 0, 0);
	276	if (ret < 0) {
	277	err = ret;
	278	break;
	279	}
	280
	281	leaf = path->nodes[0];
	282	if (path->slots[0] >= btrfs_header_nritems(leaf)) {
	283	ret = btrfs_next_leaf(tree_root, path);
	284	if (ret < 0)
	285	err = ret;
	286	if (ret != 0)
	287	break;
	288	leaf = path->nodes[0];
	289	}
	290
	291	btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
	292	btrfs_release_path(tree_root, path);
	293
	294	if (key.objectid != BTRFS_ORPHAN_OBJECTID \|\|
	295	key.type != BTRFS_ORPHAN_ITEM_KEY)
	296	break;
	297
	298	ret = btrfs_find_dead_roots(tree_root, key.offset);
	299	if (ret) {
	300	err = ret;
	301	break;
	302	}
	303
	304	key.offset++;
	305	}
	306
	307	btrfs_free_path(path);
	308	return err;
	309	}
	310
d352ac68	311	/* drop the root item for 'key' from 'root' */
e089f05c CM	312	int btrfs_del_root(struct btrfs_trans_handle trans, struct btrfs_root root,
e089f05c CM	313	struct btrfs_key *key)
3768f368	314	{
5caf2a00	315	struct btrfs_path *path;
3768f368	316	int ret;
c5739bba CM	317	u32 refs;
c5739bba CM	318	struct btrfs_root_item *ri;
5f39d397	319	struct extent_buffer *leaf;
3768f368	320
5caf2a00 CM	321	path = btrfs_alloc_path();
5caf2a00 CM	322	BUG_ON(!path);
5caf2a00	323	ret = btrfs_search_slot(trans, root, key, path, -1, 1);
3768f368 CM	324	if (ret < 0)
3768f368 CM	325	goto out;
edbd8d4e	326
3768f368	327	BUG_ON(ret != 0);
5f39d397 CM	328	leaf = path->nodes[0];
5f39d397 CM	329	ri = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_item);
c5739bba	330
5f39d397	331	refs = btrfs_disk_root_refs(leaf, ri);
5eda7b5e CM	332	BUG_ON(refs != 0);
5eda7b5e CM	333	ret = btrfs_del_item(trans, root, path);
3768f368	334	out:
5caf2a00 CM	335	btrfs_release_path(root, path);
5caf2a00 CM	336	btrfs_free_path(path);
3768f368 CM	337	return ret;
3768f368 CM	338	}
0660b5af CM	339
	340	int btrfs_del_root_ref(struct btrfs_trans_handle *trans,
	341	struct btrfs_root *tree_root,
4df27c4d YZ	342	u64 root_id, u64 ref_id, u64 dirid, u64 *sequence,
	343	const char *name, int name_len)
	344
0660b5af	345	{
4df27c4d YZ	346	struct btrfs_path *path;
	347	struct btrfs_root_ref *ref;
	348	struct extent_buffer *leaf;
0660b5af	349	struct btrfs_key key;
4df27c4d YZ	350	unsigned long ptr;
4df27c4d YZ	351	int err = 0;
0660b5af	352	int ret;
0660b5af CM	353
0660b5af CM	354	path = btrfs_alloc_path();
4df27c4d YZ	355	if (!path)
4df27c4d YZ	356	return -ENOMEM;
0660b5af CM	357
0660b5af CM	358	key.objectid = root_id;
4df27c4d	359	key.type = BTRFS_ROOT_BACKREF_KEY;
0660b5af	360	key.offset = ref_id;
4df27c4d	361	again:
0660b5af	362	ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
4df27c4d YZ	363	BUG_ON(ret < 0);
	364	if (ret == 0) {
	365	leaf = path->nodes[0];
	366	ref = btrfs_item_ptr(leaf, path->slots[0],
	367	struct btrfs_root_ref);
	368
	369	WARN_ON(btrfs_root_ref_dirid(leaf, ref) != dirid);
	370	WARN_ON(btrfs_root_ref_name_len(leaf, ref) != name_len);
	371	ptr = (unsigned long)(ref + 1);
	372	WARN_ON(memcmp_extent_buffer(leaf, name, ptr, name_len));
	373	*sequence = btrfs_root_ref_sequence(leaf, ref);
	374
	375	ret = btrfs_del_item(trans, tree_root, path);
	376	BUG_ON(ret);
	377	} else
	378	err = -ENOENT;
	379
	380	if (key.type == BTRFS_ROOT_BACKREF_KEY) {
	381	btrfs_release_path(tree_root, path);
	382	key.objectid = ref_id;
	383	key.type = BTRFS_ROOT_REF_KEY;
	384	key.offset = root_id;
	385	goto again;
	386	}
0660b5af CM	387
0660b5af CM	388	btrfs_free_path(path);
4df27c4d	389	return err;
0660b5af CM	390	}
0660b5af CM	391
ea9e8b11 CM	392	int btrfs_find_root_ref(struct btrfs_root *tree_root,
	393	struct btrfs_path *path,
	394	u64 root_id, u64 ref_id)
	395	{
	396	struct btrfs_key key;
	397	int ret;
	398
	399	key.objectid = root_id;
	400	key.type = BTRFS_ROOT_REF_KEY;
	401	key.offset = ref_id;
	402
	403	ret = btrfs_search_slot(NULL, tree_root, &key, path, 0, 0);
	404	return ret;
	405	}
	406
0660b5af CM	407	/*
	408	* add a btrfs_root_ref item. type is either BTRFS_ROOT_REF_KEY
	409	* or BTRFS_ROOT_BACKREF_KEY.
	410	*
	411	* The dirid, sequence, name and name_len refer to the directory entry
	412	* that is referencing the root.
	413	*
	414	* For a forward ref, the root_id is the id of the tree referencing
	415	* the root and ref_id is the id of the subvol or snapshot.
	416	*
	417	* For a back ref the root_id is the id of the subvol or snapshot and
	418	* ref_id is the id of the tree referencing it.
	419	*/
	420	int btrfs_add_root_ref(struct btrfs_trans_handle *trans,
	421	struct btrfs_root *tree_root,
4df27c4d	422	u64 root_id, u64 ref_id, u64 dirid, u64 sequence,
0660b5af CM	423	const char *name, int name_len)
	424	{
	425	struct btrfs_key key;
	426	int ret;
	427	struct btrfs_path *path;
	428	struct btrfs_root_ref *ref;
	429	struct extent_buffer *leaf;
	430	unsigned long ptr;
	431
0660b5af	432	path = btrfs_alloc_path();
4df27c4d YZ	433	if (!path)
4df27c4d YZ	434	return -ENOMEM;
0660b5af CM	435
0660b5af CM	436	key.objectid = root_id;
4df27c4d	437	key.type = BTRFS_ROOT_BACKREF_KEY;
0660b5af	438	key.offset = ref_id;
4df27c4d	439	again:
0660b5af CM	440	ret = btrfs_insert_empty_item(trans, tree_root, path, &key,
	441	sizeof(*ref) + name_len);
	442	BUG_ON(ret);
	443
	444	leaf = path->nodes[0];
	445	ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
	446	btrfs_set_root_ref_dirid(leaf, ref, dirid);
	447	btrfs_set_root_ref_sequence(leaf, ref, sequence);
	448	btrfs_set_root_ref_name_len(leaf, ref, name_len);
	449	ptr = (unsigned long)(ref + 1);
	450	write_extent_buffer(leaf, name, ptr, name_len);
	451	btrfs_mark_buffer_dirty(leaf);
	452
4df27c4d YZ	453	if (key.type == BTRFS_ROOT_BACKREF_KEY) {
	454	btrfs_release_path(tree_root, path);
	455	key.objectid = ref_id;
	456	key.type = BTRFS_ROOT_REF_KEY;
	457	key.offset = root_id;
	458	goto again;
	459	}
	460
0660b5af	461	btrfs_free_path(path);
4df27c4d	462	return 0;
0660b5af	463	}