[linux-2.6-block.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 "hash.h"
#include "transaction.h"
#include "print-tree.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;
}

int btrfs_find_name_in_ext_backref(struct btrfs_path *path, u64 ref_objectid,
				   const char *name, int name_len,
				   struct btrfs_inode_extref **extref_ret)
{
	struct extent_buffer *leaf;
	struct btrfs_inode_extref *extref;
	unsigned long ptr;
	unsigned long name_ptr;
	u32 item_size;
	u32 cur_offset = 0;
	int ref_name_len;

	leaf = path->nodes[0];
	item_size = btrfs_item_size_nr(leaf, path->slots[0]);
	ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);

	/*
	 * Search all extended backrefs in this item. We're only
	 * looking through any collisions so most of the time this is
	 * just going to compare against one buffer. If all is well,
	 * we'll return success and the inode ref object.
	 */
	while (cur_offset < item_size) {
		extref = (struct btrfs_inode_extref *) (ptr + cur_offset);
		name_ptr = (unsigned long)(&extref->name);
		ref_name_len = btrfs_inode_extref_name_len(leaf, extref);

		if (ref_name_len == name_len &&
		    btrfs_inode_extref_parent(leaf, extref) == ref_objectid &&
		    (memcmp_extent_buffer(leaf, name, name_ptr, name_len) == 0)) {
			if (extref_ret)
				*extref_ret = extref;
			return 1;
		}

		cur_offset += ref_name_len + sizeof(*extref);
	}
	return 0;
}

static 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 ins_len,
		       int cow)
{
	int ret;
	struct btrfs_key key;
	struct btrfs_inode_ref *ref;

	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;
}

/* Returns NULL if no extref found */
struct btrfs_inode_extref *
btrfs_lookup_inode_extref(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 ins_len,
			  int cow)
{
	int ret;
	struct btrfs_key key;
	struct btrfs_inode_extref *extref;

	key.objectid = inode_objectid;
	key.type = BTRFS_INODE_EXTREF_KEY;
	key.offset = btrfs_extref_hash(ref_objectid, name, name_len);

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

int btrfs_get_inode_ref_index(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,
			      u64 *ret_index)
{
	struct btrfs_inode_ref *ref;
	struct btrfs_inode_extref *extref;
	int ins_len = mod < 0 ? -1 : 0;
	int cow = mod != 0;

	ref = btrfs_lookup_inode_ref(trans, root, path, name, name_len,
				     inode_objectid, ref_objectid, ins_len,
				     cow);
	if (IS_ERR(ref))
		return PTR_ERR(ref);

	if (ref != NULL) {
		*ret_index = btrfs_inode_ref_index(path->nodes[0], ref);
		return 0;
	}

	btrfs_release_path(path);

	extref = btrfs_lookup_inode_extref(trans, root, path, name,
					   name_len, inode_objectid,
					   ref_objectid, ins_len, cow);
	if (IS_ERR(extref))
		return PTR_ERR(extref);

	if (extref) {
		*ret_index = btrfs_inode_extref_index(path->nodes[0], extref);
		return 0;
	}

	return -ENOENT;
}

static int btrfs_del_inode_extref(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_extref *extref;
	struct extent_buffer *leaf;
	int ret;
	int del_len = name_len + sizeof(*extref);
	unsigned long ptr;
	unsigned long item_start;
	u32 item_size;

	key.objectid = inode_objectid;
	btrfs_set_key_type(&key, BTRFS_INODE_EXTREF_KEY);
	key.offset = btrfs_extref_hash(ref_objectid, name, name_len);

	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;
	if (ret < 0)
		goto out;

	/*
	 * Sanity check - did we find the right item for this name?
	 * This should always succeed so error here will make the FS
	 * readonly.
	 */
	if (!btrfs_find_name_in_ext_backref(path, ref_objectid,
					    name, name_len, &extref)) {
		btrfs_std_error(root->fs_info, -ENOENT);
		ret = -EROFS;
		goto out;
	}

	leaf = path->nodes[0];
	item_size = btrfs_item_size_nr(leaf, path->slots[0]);
	if (index)
		*index = btrfs_inode_extref_index(leaf, extref);

	if (del_len == item_size) {
		/*
		 * Common case only one ref in the item, remove the
		 * whole item.
		 */
		ret = btrfs_del_item(trans, root, path);
		goto out;
	}

	ptr = (unsigned long)extref;
	item_start = btrfs_item_ptr_offset(leaf, path->slots[0]);

	memmove_extent_buffer(leaf, ptr, ptr + del_len,
			      item_size - (ptr + del_len - item_start));

	btrfs_truncate_item(root, path, item_size - del_len, 1);

out:
	btrfs_free_path(path);

	return ret;
}

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 search_ext_refs = 0;
	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;
		search_ext_refs = 1;
		goto out;
	} else if (ret < 0) {
		goto out;
	}
	if (!find_name_in_backref(path, name, name_len, &ref)) {
		ret = -ENOENT;
		search_ext_refs = 1;
		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(root, path, item_size - sub_item_len, 1);
out:
	btrfs_free_path(path);

	if (search_ext_refs) {
		/*
		 * No refs were found, or we could not find the
		 * name in our ref array. Find and remove the extended
		 * inode ref then.
		 */
		return btrfs_del_inode_extref(trans, root, name, name_len,
					      inode_objectid, ref_objectid, index);
	}

	return ret;
}

/*
 * btrfs_insert_inode_extref() - Inserts an extended inode ref into a tree.
 *
 * The caller must have checked against BTRFS_LINK_MAX already.
 */
static int btrfs_insert_inode_extref(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_inode_extref *extref;
	int ret;
	int ins_len = name_len + sizeof(*extref);
	unsigned long ptr;
	struct btrfs_path *path;
	struct btrfs_key key;
	struct extent_buffer *leaf;
	struct btrfs_item *item;

	key.objectid = inode_objectid;
	key.type = BTRFS_INODE_EXTREF_KEY;
	key.offset = btrfs_extref_hash(ref_objectid, name, name_len);

	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) {
		if (btrfs_find_name_in_ext_backref(path, ref_objectid,
						   name, name_len, NULL))
			goto out;

		btrfs_extend_item(root, path, ins_len);
		ret = 0;
	}
	if (ret < 0)
		goto out;

	leaf = path->nodes[0];
	item = btrfs_item_nr(leaf, path->slots[0]);
	ptr = (unsigned long)btrfs_item_ptr(leaf, path->slots[0], char);
	ptr += btrfs_item_size(leaf, item) - ins_len;
	extref = (struct btrfs_inode_extref *)ptr;

	btrfs_set_inode_extref_name_len(path->nodes[0], extref, name_len);
	btrfs_set_inode_extref_index(path->nodes[0], extref, index);
	btrfs_set_inode_extref_parent(path->nodes[0], extref, ref_objectid);

	ptr = (unsigned long)&extref->name;
	write_extent_buffer(path->nodes[0], name, ptr, name_len);
	btrfs_mark_buffer_dirty(path->nodes[0]);

out:
	btrfs_free_path(path);
	return ret;
}

/* Will return 0, -ENOMEM, -EMLINK, or -EEXIST or anything from the CoW path */
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(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);

	if (ret == -EMLINK) {
		struct btrfs_super_block *disk_super = root->fs_info->super_copy;
		/* We ran out of space in the ref array. Need to
		 * add an extended ref. */
		if (btrfs_super_incompat_flags(disk_super)
		    & BTRFS_FEATURE_INCOMPAT_EXTENDED_IREF)
			ret = btrfs_insert_inode_extref(trans, root, name,
							name_len,
							inode_objectid,
							ref_objectid, index);
	}

	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"
f186373f	21	#include "hash.h"
e089f05c	22	#include "transaction.h"
727011e0	23	#include "print-tree.h"
1e1d2701	24
b2950863	25	static int find_name_in_backref(struct btrfs_path path, const char name,
3954401f CM	26	int name_len, struct btrfs_inode_ref **ref_ret)
	27	{
	28	struct extent_buffer *leaf;
	29	struct btrfs_inode_ref *ref;
	30	unsigned long ptr;
	31	unsigned long name_ptr;
	32	u32 item_size;
	33	u32 cur_offset = 0;
	34	int len;
	35
	36	leaf = path->nodes[0];
	37	item_size = btrfs_item_size_nr(leaf, path->slots[0]);
	38	ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
	39	while (cur_offset < item_size) {
	40	ref = (struct btrfs_inode_ref *)(ptr + cur_offset);
	41	len = btrfs_inode_ref_name_len(leaf, ref);
	42	name_ptr = (unsigned long)(ref + 1);
	43	cur_offset += len + sizeof(*ref);
	44	if (len != name_len)
	45	continue;
	46	if (memcmp_extent_buffer(leaf, name, name_ptr, name_len) == 0) {
	47	*ref_ret = ref;
	48	return 1;
	49	}
	50	}
	51	return 0;
	52	}
	53
f186373f MF	54	int btrfs_find_name_in_ext_backref(struct btrfs_path *path, u64 ref_objectid,
	55	const char *name, int name_len,
	56	struct btrfs_inode_extref **extref_ret)
	57	{
	58	struct extent_buffer *leaf;
	59	struct btrfs_inode_extref *extref;
	60	unsigned long ptr;
	61	unsigned long name_ptr;
	62	u32 item_size;
	63	u32 cur_offset = 0;
	64	int ref_name_len;
	65
	66	leaf = path->nodes[0];
	67	item_size = btrfs_item_size_nr(leaf, path->slots[0]);
	68	ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
	69
	70	/*
	71	* Search all extended backrefs in this item. We're only
	72	* looking through any collisions so most of the time this is
	73	* just going to compare against one buffer. If all is well,
	74	* we'll return success and the inode ref object.
	75	*/
	76	while (cur_offset < item_size) {
	77	extref = (struct btrfs_inode_extref *) (ptr + cur_offset);
	78	name_ptr = (unsigned long)(&extref->name);
	79	ref_name_len = btrfs_inode_extref_name_len(leaf, extref);
	80
	81	if (ref_name_len == name_len &&
	82	btrfs_inode_extref_parent(leaf, extref) == ref_objectid &&
	83	(memcmp_extent_buffer(leaf, name, name_ptr, name_len) == 0)) {
	84	if (extref_ret)
	85	*extref_ret = extref;
	86	return 1;
	87	}
	88
	89	cur_offset += ref_name_len + sizeof(*extref);
	90	}
	91	return 0;
	92	}
	93
	94	static struct btrfs_inode_ref *
a22285a6	95	btrfs_lookup_inode_ref(struct btrfs_trans_handle *trans,
f186373f MF	96	struct btrfs_root *root,
	97	struct btrfs_path *path,
	98	const char *name, int name_len,
	99	u64 inode_objectid, u64 ref_objectid, int ins_len,
	100	int cow)
a22285a6	101	{
f186373f	102	int ret;
a22285a6 YZ	103	struct btrfs_key key;
a22285a6 YZ	104	struct btrfs_inode_ref *ref;
a22285a6 YZ	105
	106	key.objectid = inode_objectid;
	107	key.type = BTRFS_INODE_REF_KEY;
	108	key.offset = ref_objectid;
	109
	110	ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
	111	if (ret < 0)
	112	return ERR_PTR(ret);
	113	if (ret > 0)
	114	return NULL;
	115	if (!find_name_in_backref(path, name, name_len, &ref))
	116	return NULL;
	117	return ref;
	118	}
	119
f186373f MF	120	/* Returns NULL if no extref found */
	121	struct btrfs_inode_extref *
	122	btrfs_lookup_inode_extref(struct btrfs_trans_handle *trans,
	123	struct btrfs_root *root,
	124	struct btrfs_path *path,
	125	const char *name, int name_len,
	126	u64 inode_objectid, u64 ref_objectid, int ins_len,
	127	int cow)
	128	{
	129	int ret;
	130	struct btrfs_key key;
	131	struct btrfs_inode_extref *extref;
	132
	133	key.objectid = inode_objectid;
	134	key.type = BTRFS_INODE_EXTREF_KEY;
	135	key.offset = btrfs_extref_hash(ref_objectid, name, name_len);
	136
	137	ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
	138	if (ret < 0)
	139	return ERR_PTR(ret);
	140	if (ret > 0)
	141	return NULL;
	142	if (!btrfs_find_name_in_ext_backref(path, ref_objectid, name, name_len, &extref))
	143	return NULL;
	144	return extref;
	145	}
	146
	147	int btrfs_get_inode_ref_index(struct btrfs_trans_handle *trans,
	148	struct btrfs_root *root,
	149	struct btrfs_path *path,
	150	const char *name, int name_len,
	151	u64 inode_objectid, u64 ref_objectid, int mod,
	152	u64 *ret_index)
	153	{
	154	struct btrfs_inode_ref *ref;
	155	struct btrfs_inode_extref *extref;
	156	int ins_len = mod < 0 ? -1 : 0;
	157	int cow = mod != 0;
	158
	159	ref = btrfs_lookup_inode_ref(trans, root, path, name, name_len,
	160	inode_objectid, ref_objectid, ins_len,
	161	cow);
	162	if (IS_ERR(ref))
	163	return PTR_ERR(ref);
	164
	165	if (ref != NULL) {
	166	*ret_index = btrfs_inode_ref_index(path->nodes[0], ref);
	167	return 0;
	168	}
	169
	170	btrfs_release_path(path);
	171
	172	extref = btrfs_lookup_inode_extref(trans, root, path, name,
	173	name_len, inode_objectid,
	174	ref_objectid, ins_len, cow);
	175	if (IS_ERR(extref))
	176	return PTR_ERR(extref);
	177
	178	if (extref) {
	179	*ret_index = btrfs_inode_extref_index(path->nodes[0], extref);
	180	return 0;
	181	}
	182
	183	return -ENOENT;
184	}
185
48a3b636 ES	186	static int btrfs_del_inode_extref(struct btrfs_trans_handle *trans,
	187	struct btrfs_root *root,
	188	const char *name, int name_len,
	189	u64 inode_objectid, u64 ref_objectid,
	190	u64 *index)
f186373f MF	191	{
	192	struct btrfs_path *path;
	193	struct btrfs_key key;
	194	struct btrfs_inode_extref *extref;
	195	struct extent_buffer *leaf;
	196	int ret;
	197	int del_len = name_len + sizeof(*extref);
	198	unsigned long ptr;
	199	unsigned long item_start;
	200	u32 item_size;
	201
	202	key.objectid = inode_objectid;
	203	btrfs_set_key_type(&key, BTRFS_INODE_EXTREF_KEY);
	204	key.offset = btrfs_extref_hash(ref_objectid, name, name_len);
	205
	206	path = btrfs_alloc_path();
	207	if (!path)
	208	return -ENOMEM;
	209
	210	path->leave_spinning = 1;
	211
	212	ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
	213	if (ret > 0)
	214	ret = -ENOENT;
	215	if (ret < 0)
	216	goto out;
	217
	218	/*
	219	* Sanity check - did we find the right item for this name?
	220	* This should always succeed so error here will make the FS
	221	* readonly.
	222	*/
	223	if (!btrfs_find_name_in_ext_backref(path, ref_objectid,
	224	name, name_len, &extref)) {
	225	btrfs_std_error(root->fs_info, -ENOENT);
	226	ret = -EROFS;
	227	goto out;
	228	}
	229
	230	leaf = path->nodes[0];
	231	item_size = btrfs_item_size_nr(leaf, path->slots[0]);
	232	if (index)
	233	*index = btrfs_inode_extref_index(leaf, extref);
	234
	235	if (del_len == item_size) {
	236	/*
	237	* Common case only one ref in the item, remove the
	238	* whole item.
	239	*/
	240	ret = btrfs_del_item(trans, root, path);
	241	goto out;
	242	}
	243
	244	ptr = (unsigned long)extref;
	245	item_start = btrfs_item_ptr_offset(leaf, path->slots[0]);
	246
	247	memmove_extent_buffer(leaf, ptr, ptr + del_len,
	248	item_size - (ptr + del_len - item_start));
	249
afe5fea7	250	btrfs_truncate_item(root, path, item_size - del_len, 1);
f186373f MF	251
	252	out:
	253	btrfs_free_path(path);
	254
	255	return ret;
	256	}
	257
	258	int btrfs_del_inode_ref(struct btrfs_trans_handle *trans,
	259	struct btrfs_root *root,
	260	const char *name, int name_len,
	261	u64 inode_objectid, u64 ref_objectid, u64 *index)
3954401f CM	262	{
	263	struct btrfs_path *path;
	264	struct btrfs_key key;
	265	struct btrfs_inode_ref *ref;
	266	struct extent_buffer *leaf;
	267	unsigned long ptr;
	268	unsigned long item_start;
	269	u32 item_size;
	270	u32 sub_item_len;
	271	int ret;
f186373f	272	int search_ext_refs = 0;
3954401f CM	273	int del_len = name_len + sizeof(*ref);
	274
	275	key.objectid = inode_objectid;
	276	key.offset = ref_objectid;
	277	btrfs_set_key_type(&key, BTRFS_INODE_REF_KEY);
	278
	279	path = btrfs_alloc_path();
	280	if (!path)
	281	return -ENOMEM;
	282
b9473439 CM	283	path->leave_spinning = 1;
b9473439 CM	284
3954401f CM	285	ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
	286	if (ret > 0) {
	287	ret = -ENOENT;
f186373f	288	search_ext_refs = 1;
3954401f CM	289	goto out;
	290	} else if (ret < 0) {
	291	goto out;
	292	}
	293	if (!find_name_in_backref(path, name, name_len, &ref)) {
	294	ret = -ENOENT;
f186373f	295	search_ext_refs = 1;
3954401f CM	296	goto out;
	297	}
	298	leaf = path->nodes[0];
	299	item_size = btrfs_item_size_nr(leaf, path->slots[0]);
aec7477b JB	300
	301	if (index)
	302	*index = btrfs_inode_ref_index(leaf, ref);
	303
3954401f CM	304	if (del_len == item_size) {
	305	ret = btrfs_del_item(trans, root, path);
	306	goto out;
	307	}
	308	ptr = (unsigned long)ref;
	309	sub_item_len = name_len + sizeof(*ref);
	310	item_start = btrfs_item_ptr_offset(leaf, path->slots[0]);
	311	memmove_extent_buffer(leaf, ptr, ptr + sub_item_len,
	312	item_size - (ptr + sub_item_len - item_start));
afe5fea7	313	btrfs_truncate_item(root, path, item_size - sub_item_len, 1);
f186373f MF	314	out:
	315	btrfs_free_path(path);
	316
	317	if (search_ext_refs) {
	318	/*
	319	* No refs were found, or we could not find the
	320	* name in our ref array. Find and remove the extended
	321	* inode ref then.
	322	*/
	323	return btrfs_del_inode_extref(trans, root, name, name_len,
	324	inode_objectid, ref_objectid, index);
	325	}
	326
	327	return ret;
	328	}
	329
	330	/*
	331	* btrfs_insert_inode_extref() - Inserts an extended inode ref into a tree.
	332	*
	333	* The caller must have checked against BTRFS_LINK_MAX already.
	334	*/
	335	static int btrfs_insert_inode_extref(struct btrfs_trans_handle *trans,
	336	struct btrfs_root *root,
	337	const char *name, int name_len,
	338	u64 inode_objectid, u64 ref_objectid, u64 index)
	339	{
	340	struct btrfs_inode_extref *extref;
	341	int ret;
	342	int ins_len = name_len + sizeof(*extref);
	343	unsigned long ptr;
	344	struct btrfs_path *path;
	345	struct btrfs_key key;
	346	struct extent_buffer *leaf;
	347	struct btrfs_item *item;
	348
	349	key.objectid = inode_objectid;
	350	key.type = BTRFS_INODE_EXTREF_KEY;
	351	key.offset = btrfs_extref_hash(ref_objectid, name, name_len);
	352
	353	path = btrfs_alloc_path();
	354	if (!path)
	355	return -ENOMEM;
	356
	357	path->leave_spinning = 1;
	358	ret = btrfs_insert_empty_item(trans, root, path, &key,
	359	ins_len);
	360	if (ret == -EEXIST) {
	361	if (btrfs_find_name_in_ext_backref(path, ref_objectid,
	362	name, name_len, NULL))
	363	goto out;
	364
4b90c680	365	btrfs_extend_item(root, path, ins_len);
f186373f MF	366	ret = 0;
	367	}
	368	if (ret < 0)
	369	goto out;
	370
	371	leaf = path->nodes[0];
	372	item = btrfs_item_nr(leaf, path->slots[0]);
	373	ptr = (unsigned long)btrfs_item_ptr(leaf, path->slots[0], char);
	374	ptr += btrfs_item_size(leaf, item) - ins_len;
	375	extref = (struct btrfs_inode_extref *)ptr;
	376
	377	btrfs_set_inode_extref_name_len(path->nodes[0], extref, name_len);
	378	btrfs_set_inode_extref_index(path->nodes[0], extref, index);
	379	btrfs_set_inode_extref_parent(path->nodes[0], extref, ref_objectid);
	380
	381	ptr = (unsigned long)&extref->name;
	382	write_extent_buffer(path->nodes[0], name, ptr, name_len);
	383	btrfs_mark_buffer_dirty(path->nodes[0]);
	384
3954401f CM	385	out:
	386	btrfs_free_path(path);
	387	return ret;
	388	}
	389
79787eaa	390	/* Will return 0, -ENOMEM, -EMLINK, or -EEXIST or anything from the CoW path */
3954401f CM	391	int btrfs_insert_inode_ref(struct btrfs_trans_handle *trans,
	392	struct btrfs_root *root,
	393	const char *name, int name_len,
aec7477b	394	u64 inode_objectid, u64 ref_objectid, u64 index)
3954401f CM	395	{
	396	struct btrfs_path *path;
	397	struct btrfs_key key;
	398	struct btrfs_inode_ref *ref;
	399	unsigned long ptr;
	400	int ret;
	401	int ins_len = name_len + sizeof(*ref);
	402
	403	key.objectid = inode_objectid;
	404	key.offset = ref_objectid;
	405	btrfs_set_key_type(&key, BTRFS_INODE_REF_KEY);
	406
	407	path = btrfs_alloc_path();
	408	if (!path)
	409	return -ENOMEM;
	410
b9473439	411	path->leave_spinning = 1;
3954401f CM	412	ret = btrfs_insert_empty_item(trans, root, path, &key,
	413	ins_len);
	414	if (ret == -EEXIST) {
	415	u32 old_size;
	416
	417	if (find_name_in_backref(path, name, name_len, &ref))
	418	goto out;
	419
	420	old_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
4b90c680	421	btrfs_extend_item(root, path, ins_len);
3954401f CM	422	ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
	423	struct btrfs_inode_ref);
	424	ref = (struct btrfs_inode_ref *)((unsigned long)ref + old_size);
	425	btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
aec7477b	426	btrfs_set_inode_ref_index(path->nodes[0], ref, index);
3954401f CM	427	ptr = (unsigned long)(ref + 1);
	428	ret = 0;
	429	} else if (ret < 0) {
a5719521 YZ	430	if (ret == -EOVERFLOW)
a5719521 YZ	431	ret = -EMLINK;
3954401f CM	432	goto out;
	433	} else {
	434	ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
	435	struct btrfs_inode_ref);
	436	btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
aec7477b	437	btrfs_set_inode_ref_index(path->nodes[0], ref, index);
3954401f CM	438	ptr = (unsigned long)(ref + 1);
	439	}
	440	write_extent_buffer(path->nodes[0], name, ptr, name_len);
	441	btrfs_mark_buffer_dirty(path->nodes[0]);
	442
	443	out:
	444	btrfs_free_path(path);
f186373f MF	445
	446	if (ret == -EMLINK) {
	447	struct btrfs_super_block *disk_super = root->fs_info->super_copy;
	448	/* We ran out of space in the ref array. Need to
	449	* add an extended ref. */
	450	if (btrfs_super_incompat_flags(disk_super)
	451	& BTRFS_FEATURE_INCOMPAT_EXTENDED_IREF)
	452	ret = btrfs_insert_inode_extref(trans, root, name,
	453	name_len,
	454	inode_objectid,
	455	ref_objectid, index);
	456	}
	457
3954401f CM	458	return ret;
	459	}
	460
5f39d397 CM	461	int btrfs_insert_empty_inode(struct btrfs_trans_handle *trans,
	462	struct btrfs_root *root,
	463	struct btrfs_path *path, u64 objectid)
1e1d2701	464	{
1e1d2701 CM	465	struct btrfs_key key;
	466	int ret;
	467	key.objectid = objectid;
1e1d2701 CM	468	btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
	469	key.offset = 0;
	470
5f39d397 CM	471	ret = btrfs_insert_empty_item(trans, root, path, &key,
5f39d397 CM	472	sizeof(struct btrfs_inode_item));
1e1d2701 CM	473	return ret;
	474	}
	475
e089f05c	476	int btrfs_lookup_inode(struct btrfs_trans_handle *trans, struct btrfs_root
d6e4a428 CM	477	root, struct btrfs_path path,
d6e4a428 CM	478	struct btrfs_key *location, int mod)
1e1d2701	479	{
1e1d2701 CM	480	int ins_len = mod < 0 ? -1 : 0;
1e1d2701 CM	481	int cow = mod != 0;
d6e4a428 CM	482	int ret;
d6e4a428 CM	483	int slot;
5f39d397	484	struct extent_buffer *leaf;
d6e4a428	485	struct btrfs_key found_key;
1e1d2701	486
d6e4a428 CM	487	ret = btrfs_search_slot(trans, root, location, path, ins_len, cow);
	488	if (ret > 0 && btrfs_key_type(location) == BTRFS_ROOT_ITEM_KEY &&
	489	location->offset == (u64)-1 && path->slots[0] != 0) {
	490	slot = path->slots[0] - 1;
5f39d397 CM	491	leaf = path->nodes[0];
5f39d397 CM	492	btrfs_item_key_to_cpu(leaf, &found_key, slot);
d6e4a428 CM	493	if (found_key.objectid == location->objectid &&
	494	btrfs_key_type(&found_key) == btrfs_key_type(location)) {
	495	path->slots[0]--;
	496	return 0;
	497	}
	498	}
	499	return ret;
1e1d2701	500	}