[linux.git] / fs / btrfs / inode-item.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 "disk-io.h"
#include "transaction.h"

static int find_name_in_backref(struct btrfs_path *path, const char *name,
			 int name_len, struct btrfs_inode_ref **ref_ret)
{
	struct extent_buffer *leaf;
	struct btrfs_inode_ref *ref;
	unsigned long ptr;
	unsigned long name_ptr;
	u32 item_size;
	u32 cur_offset = 0;
	int len;

	leaf = path->nodes[0];
	item_size = btrfs_item_size_nr(leaf, path->slots[0]);
	ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
	while (cur_offset < item_size) {
		ref = (struct btrfs_inode_ref *)(ptr + cur_offset);
		len = btrfs_inode_ref_name_len(leaf, ref);
		name_ptr = (unsigned long)(ref + 1);
		cur_offset += len + sizeof(*ref);
		if (len != name_len)
			continue;
		if (memcmp_extent_buffer(leaf, name, name_ptr, name_len) == 0) {
			*ref_ret = ref;
			return 1;
		}
	}
	return 0;
}

struct btrfs_inode_ref *
btrfs_lookup_inode_ref(struct btrfs_trans_handle *trans,
			struct btrfs_root *root,
			struct btrfs_path *path,
			const char *name, int name_len,
			u64 inode_objectid, u64 ref_objectid, int mod)
{
	struct btrfs_key key;
	struct btrfs_inode_ref *ref;
	int ins_len = mod < 0 ? -1 : 0;
	int cow = mod != 0;
	int ret;

	key.objectid = inode_objectid;
	key.type = BTRFS_INODE_REF_KEY;
	key.offset = ref_objectid;

	ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
	if (ret < 0)
		return ERR_PTR(ret);
	if (ret > 0)
		return NULL;
	if (!find_name_in_backref(path, name, name_len, &ref))
		return NULL;
	return ref;
}

int btrfs_del_inode_ref(struct btrfs_trans_handle *trans,
			   struct btrfs_root *root,
			   const char *name, int name_len,
			   u64 inode_objectid, u64 ref_objectid, u64 *index)
{
	struct btrfs_path *path;
	struct btrfs_key key;
	struct btrfs_inode_ref *ref;
	struct extent_buffer *leaf;
	unsigned long ptr;
	unsigned long item_start;
	u32 item_size;
	u32 sub_item_len;
	int ret;
	int del_len = name_len + sizeof(*ref);

	key.objectid = inode_objectid;
	key.offset = ref_objectid;
	btrfs_set_key_type(&key, BTRFS_INODE_REF_KEY);

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

	path->leave_spinning = 1;

	ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
	if (ret > 0) {
		ret = -ENOENT;
		goto out;
	} else if (ret < 0) {
		goto out;
	}
	if (!find_name_in_backref(path, name, name_len, &ref)) {
		ret = -ENOENT;
		goto out;
	}
	leaf = path->nodes[0];
	item_size = btrfs_item_size_nr(leaf, path->slots[0]);

	if (index)
		*index = btrfs_inode_ref_index(leaf, ref);

	if (del_len == item_size) {
		ret = btrfs_del_item(trans, root, path);
		goto out;
	}
	ptr = (unsigned long)ref;
	sub_item_len = name_len + sizeof(*ref);
	item_start = btrfs_item_ptr_offset(leaf, path->slots[0]);
	memmove_extent_buffer(leaf, ptr, ptr + sub_item_len,
			      item_size - (ptr + sub_item_len - item_start));
	btrfs_truncate_item(trans, root, path,
				  item_size - sub_item_len, 1);
out:
	btrfs_free_path(path);
	return ret;
}

int btrfs_insert_inode_ref(struct btrfs_trans_handle *trans,
			   struct btrfs_root *root,
			   const char *name, int name_len,
			   u64 inode_objectid, u64 ref_objectid, u64 index)
{
	struct btrfs_path *path;
	struct btrfs_key key;
	struct btrfs_inode_ref *ref;
	unsigned long ptr;
	int ret;
	int ins_len = name_len + sizeof(*ref);

	key.objectid = inode_objectid;
	key.offset = ref_objectid;
	btrfs_set_key_type(&key, BTRFS_INODE_REF_KEY);

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

	path->leave_spinning = 1;
	ret = btrfs_insert_empty_item(trans, root, path, &key,
				      ins_len);
	if (ret == -EEXIST) {
		u32 old_size;

		if (find_name_in_backref(path, name, name_len, &ref))
			goto out;

		old_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
		btrfs_extend_item(trans, root, path, ins_len);
		ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
				     struct btrfs_inode_ref);
		ref = (struct btrfs_inode_ref *)((unsigned long)ref + old_size);
		btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
		btrfs_set_inode_ref_index(path->nodes[0], ref, index);
		ptr = (unsigned long)(ref + 1);
		ret = 0;
	} else if (ret < 0) {
		if (ret == -EOVERFLOW)
			ret = -EMLINK;
		goto out;
	} else {
		ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
				     struct btrfs_inode_ref);
		btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
		btrfs_set_inode_ref_index(path->nodes[0], ref, index);
		ptr = (unsigned long)(ref + 1);
	}
	write_extent_buffer(path->nodes[0], name, ptr, name_len);
	btrfs_mark_buffer_dirty(path->nodes[0]);

out:
	btrfs_free_path(path);
	return ret;
}

int btrfs_insert_empty_inode(struct btrfs_trans_handle *trans,
			     struct btrfs_root *root,
			     struct btrfs_path *path, u64 objectid)
{
	struct btrfs_key key;
	int ret;
	key.objectid = objectid;
	btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
	key.offset = 0;

	ret = btrfs_insert_empty_item(trans, root, path, &key,
				      sizeof(struct btrfs_inode_item));
	return ret;
}

int btrfs_lookup_inode(struct btrfs_trans_handle *trans, struct btrfs_root
		       *root, struct btrfs_path *path,
		       struct btrfs_key *location, int mod)
{
	int ins_len = mod < 0 ? -1 : 0;
	int cow = mod != 0;
	int ret;
	int slot;
	struct extent_buffer *leaf;
	struct btrfs_key found_key;

	ret = btrfs_search_slot(trans, root, location, path, ins_len, cow);
	if (ret > 0 && btrfs_key_type(location) == BTRFS_ROOT_ITEM_KEY &&
	    location->offset == (u64)-1 && path->slots[0] != 0) {
		slot = path->slots[0] - 1;
		leaf = path->nodes[0];
		btrfs_item_key_to_cpu(leaf, &found_key, slot);
		if (found_key.objectid == location->objectid &&
		    btrfs_key_type(&found_key) == btrfs_key_type(location)) {
			path->slots[0]--;
			return 0;
		}
	}
	return ret;
}
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
1e1d2701 CM	19	#include "ctree.h"
1e1d2701 CM	20	#include "disk-io.h"
e089f05c	21	#include "transaction.h"
1e1d2701	22
b2950863	23	static int find_name_in_backref(struct btrfs_path path, const char name,
3954401f CM	24	int name_len, struct btrfs_inode_ref **ref_ret)
	25	{
	26	struct extent_buffer *leaf;
	27	struct btrfs_inode_ref *ref;
	28	unsigned long ptr;
	29	unsigned long name_ptr;
	30	u32 item_size;
	31	u32 cur_offset = 0;
	32	int len;
	33
	34	leaf = path->nodes[0];
	35	item_size = btrfs_item_size_nr(leaf, path->slots[0]);
	36	ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
	37	while (cur_offset < item_size) {
	38	ref = (struct btrfs_inode_ref *)(ptr + cur_offset);
	39	len = btrfs_inode_ref_name_len(leaf, ref);
	40	name_ptr = (unsigned long)(ref + 1);
	41	cur_offset += len + sizeof(*ref);
	42	if (len != name_len)
	43	continue;
	44	if (memcmp_extent_buffer(leaf, name, name_ptr, name_len) == 0) {
	45	*ref_ret = ref;
	46	return 1;
	47	}
	48	}
	49	return 0;
	50	}
	51
a22285a6 YZ	52	struct btrfs_inode_ref *
	53	btrfs_lookup_inode_ref(struct btrfs_trans_handle *trans,
	54	struct btrfs_root *root,
	55	struct btrfs_path *path,
	56	const char *name, int name_len,
	57	u64 inode_objectid, u64 ref_objectid, int mod)
	58	{
	59	struct btrfs_key key;
	60	struct btrfs_inode_ref *ref;
	61	int ins_len = mod < 0 ? -1 : 0;
	62	int cow = mod != 0;
	63	int ret;
	64
	65	key.objectid = inode_objectid;
	66	key.type = BTRFS_INODE_REF_KEY;
	67	key.offset = ref_objectid;
	68
	69	ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
	70	if (ret < 0)
	71	return ERR_PTR(ret);
	72	if (ret > 0)
	73	return NULL;
	74	if (!find_name_in_backref(path, name, name_len, &ref))
	75	return NULL;
	76	return ref;
	77	}
	78
3954401f CM	79	int btrfs_del_inode_ref(struct btrfs_trans_handle *trans,
	80	struct btrfs_root *root,
	81	const char *name, int name_len,
aec7477b	82	u64 inode_objectid, u64 ref_objectid, u64 *index)
3954401f CM	83	{
	84	struct btrfs_path *path;
	85	struct btrfs_key key;
	86	struct btrfs_inode_ref *ref;
	87	struct extent_buffer *leaf;
	88	unsigned long ptr;
	89	unsigned long item_start;
	90	u32 item_size;
	91	u32 sub_item_len;
	92	int ret;
	93	int del_len = name_len + sizeof(*ref);
	94
	95	key.objectid = inode_objectid;
	96	key.offset = ref_objectid;
	97	btrfs_set_key_type(&key, BTRFS_INODE_REF_KEY);
	98
	99	path = btrfs_alloc_path();
	100	if (!path)
	101	return -ENOMEM;
	102
b9473439 CM	103	path->leave_spinning = 1;
b9473439 CM	104
3954401f CM	105	ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
	106	if (ret > 0) {
	107	ret = -ENOENT;
	108	goto out;
	109	} else if (ret < 0) {
	110	goto out;
	111	}
	112	if (!find_name_in_backref(path, name, name_len, &ref)) {
	113	ret = -ENOENT;
	114	goto out;
	115	}
	116	leaf = path->nodes[0];
	117	item_size = btrfs_item_size_nr(leaf, path->slots[0]);
aec7477b JB	118
	119	if (index)
	120	*index = btrfs_inode_ref_index(leaf, ref);
	121
3954401f CM	122	if (del_len == item_size) {
	123	ret = btrfs_del_item(trans, root, path);
	124	goto out;
	125	}
	126	ptr = (unsigned long)ref;
	127	sub_item_len = name_len + sizeof(*ref);
	128	item_start = btrfs_item_ptr_offset(leaf, path->slots[0]);
	129	memmove_extent_buffer(leaf, ptr, ptr + sub_item_len,
	130	item_size - (ptr + sub_item_len - item_start));
143bede5	131	btrfs_truncate_item(trans, root, path,
3954401f	132	item_size - sub_item_len, 1);
3954401f CM	133	out:
	134	btrfs_free_path(path);
	135	return ret;
	136	}
	137
	138	int btrfs_insert_inode_ref(struct btrfs_trans_handle *trans,
	139	struct btrfs_root *root,
	140	const char *name, int name_len,
aec7477b	141	u64 inode_objectid, u64 ref_objectid, u64 index)
3954401f CM	142	{
	143	struct btrfs_path *path;
	144	struct btrfs_key key;
	145	struct btrfs_inode_ref *ref;
	146	unsigned long ptr;
	147	int ret;
	148	int ins_len = name_len + sizeof(*ref);
	149
	150	key.objectid = inode_objectid;
	151	key.offset = ref_objectid;
	152	btrfs_set_key_type(&key, BTRFS_INODE_REF_KEY);
	153
	154	path = btrfs_alloc_path();
	155	if (!path)
	156	return -ENOMEM;
	157
b9473439	158	path->leave_spinning = 1;
3954401f CM	159	ret = btrfs_insert_empty_item(trans, root, path, &key,
	160	ins_len);
	161	if (ret == -EEXIST) {
	162	u32 old_size;
	163
	164	if (find_name_in_backref(path, name, name_len, &ref))
	165	goto out;
	166
	167	old_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
143bede5	168	btrfs_extend_item(trans, root, path, ins_len);
3954401f CM	169	ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
	170	struct btrfs_inode_ref);
	171	ref = (struct btrfs_inode_ref *)((unsigned long)ref + old_size);
	172	btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
aec7477b	173	btrfs_set_inode_ref_index(path->nodes[0], ref, index);
3954401f CM	174	ptr = (unsigned long)(ref + 1);
	175	ret = 0;
	176	} else if (ret < 0) {
a5719521 YZ	177	if (ret == -EOVERFLOW)
a5719521 YZ	178	ret = -EMLINK;
3954401f CM	179	goto out;
	180	} else {
	181	ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
	182	struct btrfs_inode_ref);
	183	btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
aec7477b	184	btrfs_set_inode_ref_index(path->nodes[0], ref, index);
3954401f CM	185	ptr = (unsigned long)(ref + 1);
	186	}
	187	write_extent_buffer(path->nodes[0], name, ptr, name_len);
	188	btrfs_mark_buffer_dirty(path->nodes[0]);
	189
	190	out:
	191	btrfs_free_path(path);
	192	return ret;
	193	}
	194
5f39d397 CM	195	int btrfs_insert_empty_inode(struct btrfs_trans_handle *trans,
	196	struct btrfs_root *root,
	197	struct btrfs_path *path, u64 objectid)
1e1d2701	198	{
1e1d2701 CM	199	struct btrfs_key key;
	200	int ret;
	201	key.objectid = objectid;
1e1d2701 CM	202	btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
	203	key.offset = 0;
	204
5f39d397 CM	205	ret = btrfs_insert_empty_item(trans, root, path, &key,
5f39d397 CM	206	sizeof(struct btrfs_inode_item));
1e1d2701 CM	207	return ret;
	208	}
	209
e089f05c	210	int btrfs_lookup_inode(struct btrfs_trans_handle *trans, struct btrfs_root
d6e4a428 CM	211	root, struct btrfs_path path,
d6e4a428 CM	212	struct btrfs_key *location, int mod)
1e1d2701	213	{
1e1d2701 CM	214	int ins_len = mod < 0 ? -1 : 0;
1e1d2701 CM	215	int cow = mod != 0;
d6e4a428 CM	216	int ret;
d6e4a428 CM	217	int slot;
5f39d397	218	struct extent_buffer *leaf;
d6e4a428	219	struct btrfs_key found_key;
1e1d2701	220
d6e4a428 CM	221	ret = btrfs_search_slot(trans, root, location, path, ins_len, cow);
	222	if (ret > 0 && btrfs_key_type(location) == BTRFS_ROOT_ITEM_KEY &&
	223	location->offset == (u64)-1 && path->slots[0] != 0) {
	224	slot = path->slots[0] - 1;
5f39d397 CM	225	leaf = path->nodes[0];
5f39d397 CM	226	btrfs_item_key_to_cpu(leaf, &found_key, slot);
d6e4a428 CM	227	if (found_key.objectid == location->objectid &&
	228	btrfs_key_type(&found_key) == btrfs_key_type(location)) {
	229	path->slots[0]--;
	230	return 0;
	231	}
	232	}
	233	return ret;
1e1d2701	234	}