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
19#include "ctree.h"
20#include "disk-io.h"
21#include "hash.h"
22#include "transaction.h"
23
24/*
25 * insert a name into a directory, doing overflow properly if there is a hash
26 * collision.  data_size indicates how big the item inserted should be.  On
27 * success a struct btrfs_dir_item pointer is returned, otherwise it is
28 * an ERR_PTR.
29 *
30 * The name is not copied into the dir item, you have to do that yourself.
31 */
32static struct btrfs_dir_item *insert_with_overflow(struct btrfs_trans_handle
33						   *trans,
34						   struct btrfs_root *root,
35						   struct btrfs_path *path,
36						   struct btrfs_key *cpu_key,
37						   u32 data_size,
38						   const char *name,
39						   int name_len)
40{
41	int ret;
42	char *ptr;
43	struct btrfs_item *item;
44	struct extent_buffer *leaf;
45
46	ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
47	if (ret == -EEXIST) {
48		struct btrfs_dir_item *di;
49		di = btrfs_match_dir_item_name(root, path, name, name_len);
50		if (di)
51			return ERR_PTR(-EEXIST);
52		ret = btrfs_extend_item(trans, root, path, data_size);
53	}
54	if (ret < 0)
55		return ERR_PTR(ret);
56	WARN_ON(ret > 0);
57	leaf = path->nodes[0];
58	item = btrfs_item_nr(leaf, path->slots[0]);
59	ptr = btrfs_item_ptr(leaf, path->slots[0], char);
60	BUG_ON(data_size > btrfs_item_size(leaf, item));
61	ptr += btrfs_item_size(leaf, item) - data_size;
62	return (struct btrfs_dir_item *)ptr;
63}
64
65/*
66 * xattrs work a lot like directories, this inserts an xattr item
67 * into the tree
68 */
69int btrfs_insert_xattr_item(struct btrfs_trans_handle *trans,
70			    struct btrfs_root *root,
71			    struct btrfs_path *path, u64 objectid,
72			    const char *name, u16 name_len,
73			    const void *data, u16 data_len)
74{
75	int ret = 0;
76	struct btrfs_dir_item *dir_item;
77	unsigned long name_ptr, data_ptr;
78	struct btrfs_key key, location;
79	struct btrfs_disk_key disk_key;
80	struct extent_buffer *leaf;
81	u32 data_size;
82
83	BUG_ON(name_len + data_len > BTRFS_MAX_XATTR_SIZE(root));
84
85	key.objectid = objectid;
86	btrfs_set_key_type(&key, BTRFS_XATTR_ITEM_KEY);
87	key.offset = btrfs_name_hash(name, name_len);
88
89	data_size = sizeof(*dir_item) + name_len + data_len;
90	dir_item = insert_with_overflow(trans, root, path, &key, data_size,
91					name, name_len);
92	if (IS_ERR(dir_item))
93		return PTR_ERR(dir_item);
94	memset(&location, 0, sizeof(location));
95
96	leaf = path->nodes[0];
97	btrfs_cpu_key_to_disk(&disk_key, &location);
98	btrfs_set_dir_item_key(leaf, dir_item, &disk_key);
99	btrfs_set_dir_type(leaf, dir_item, BTRFS_FT_XATTR);
100	btrfs_set_dir_name_len(leaf, dir_item, name_len);
101	btrfs_set_dir_transid(leaf, dir_item, trans->transid);
102	btrfs_set_dir_data_len(leaf, dir_item, data_len);
103	name_ptr = (unsigned long)(dir_item + 1);
104	data_ptr = (unsigned long)((char *)name_ptr + name_len);
105
106	write_extent_buffer(leaf, name, name_ptr, name_len);
107	write_extent_buffer(leaf, data, data_ptr, data_len);
108	btrfs_mark_buffer_dirty(path->nodes[0]);
109
110	return ret;
111}
112
113/*
114 * insert a directory item in the tree, doing all the magic for
115 * both indexes. 'dir' indicates which objectid to insert it into,
116 * 'location' is the key to stuff into the directory item, 'type' is the
117 * type of the inode we're pointing to, and 'index' is the sequence number
118 * to use for the second index (if one is created).
119 */
120int btrfs_insert_dir_item(struct btrfs_trans_handle *trans, struct btrfs_root
121			  *root, const char *name, int name_len,
122			  struct inode *dir, struct btrfs_key *location,
123			  u8 type, u64 index)
124{
125	int ret = 0;
126	int ret2 = 0;
127	struct btrfs_path *path;
128	struct btrfs_dir_item *dir_item;
129	struct extent_buffer *leaf;
130	unsigned long name_ptr;
131	struct btrfs_key key;
132	struct btrfs_disk_key disk_key;
133	u32 data_size;
134
135	key.objectid = btrfs_ino(dir);
136	btrfs_set_key_type(&key, BTRFS_DIR_ITEM_KEY);
137	key.offset = btrfs_name_hash(name, name_len);
138
139	path = btrfs_alloc_path();
140	if (!path)
141		return -ENOMEM;
142	path->leave_spinning = 1;
143
144	btrfs_cpu_key_to_disk(&disk_key, location);
145
146	data_size = sizeof(*dir_item) + name_len;
147	dir_item = insert_with_overflow(trans, root, path, &key, data_size,
148					name, name_len);
149	if (IS_ERR(dir_item)) {
150		ret = PTR_ERR(dir_item);
151		if (ret == -EEXIST)
152			goto second_insert;
153		goto out_free;
154	}
155
156	leaf = path->nodes[0];
157	btrfs_set_dir_item_key(leaf, dir_item, &disk_key);
158	btrfs_set_dir_type(leaf, dir_item, type);
159	btrfs_set_dir_data_len(leaf, dir_item, 0);
160	btrfs_set_dir_name_len(leaf, dir_item, name_len);
161	btrfs_set_dir_transid(leaf, dir_item, trans->transid);
162	name_ptr = (unsigned long)(dir_item + 1);
163
164	write_extent_buffer(leaf, name, name_ptr, name_len);
165	btrfs_mark_buffer_dirty(leaf);
166
167second_insert:
168	/* FIXME, use some real flag for selecting the extra index */
169	if (root == root->fs_info->tree_root) {
170		ret = 0;
171		goto out_free;
172	}
173	btrfs_release_path(path);
174
175	ret2 = btrfs_insert_delayed_dir_index(trans, root, name, name_len, dir,
176					      &disk_key, type, index);
177out_free:
178	btrfs_free_path(path);
179	if (ret)
180		return ret;
181	if (ret2)
182		return ret2;
183	return 0;
184}
185
186/*
187 * lookup a directory item based on name.  'dir' is the objectid
188 * we're searching in, and 'mod' tells us if you plan on deleting the
189 * item (use mod < 0) or changing the options (use mod > 0)
190 */
191struct btrfs_dir_item *btrfs_lookup_dir_item(struct btrfs_trans_handle *trans,
192					     struct btrfs_root *root,
193					     struct btrfs_path *path, u64 dir,
194					     const char *name, int name_len,
195					     int mod)
196{
197	int ret;
198	struct btrfs_key key;
199	int ins_len = mod < 0 ? -1 : 0;
200	int cow = mod != 0;
201
202	key.objectid = dir;
203	btrfs_set_key_type(&key, BTRFS_DIR_ITEM_KEY);
204
205	key.offset = btrfs_name_hash(name, name_len);
206
207	ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
208	if (ret < 0)
209		return ERR_PTR(ret);
210	if (ret > 0)
211		return NULL;
212
213	return btrfs_match_dir_item_name(root, path, name, name_len);
214}
215
216/*
217 * lookup a directory item based on index.  'dir' is the objectid
218 * we're searching in, and 'mod' tells us if you plan on deleting the
219 * item (use mod < 0) or changing the options (use mod > 0)
220 *
221 * The name is used to make sure the index really points to the name you were
222 * looking for.
223 */
224struct btrfs_dir_item *
225btrfs_lookup_dir_index_item(struct btrfs_trans_handle *trans,
226			    struct btrfs_root *root,
227			    struct btrfs_path *path, u64 dir,
228			    u64 objectid, const char *name, int name_len,
229			    int mod)
230{
231	int ret;
232	struct btrfs_key key;
233	int ins_len = mod < 0 ? -1 : 0;
234	int cow = mod != 0;
235
236	key.objectid = dir;
237	btrfs_set_key_type(&key, BTRFS_DIR_INDEX_KEY);
238	key.offset = objectid;
239
240	ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
241	if (ret < 0)
242		return ERR_PTR(ret);
243	if (ret > 0)
244		return ERR_PTR(-ENOENT);
245	return btrfs_match_dir_item_name(root, path, name, name_len);
246}
247
248struct btrfs_dir_item *
249btrfs_search_dir_index_item(struct btrfs_root *root,
250			    struct btrfs_path *path, u64 dirid,
251			    const char *name, int name_len)
252{
253	struct extent_buffer *leaf;
254	struct btrfs_dir_item *di;
255	struct btrfs_key key;
256	u32 nritems;
257	int ret;
258
259	key.objectid = dirid;
260	key.type = BTRFS_DIR_INDEX_KEY;
261	key.offset = 0;
262
263	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
264	if (ret < 0)
265		return ERR_PTR(ret);
266
267	leaf = path->nodes[0];
268	nritems = btrfs_header_nritems(leaf);
269
270	while (1) {
271		if (path->slots[0] >= nritems) {
272			ret = btrfs_next_leaf(root, path);
273			if (ret < 0)
274				return ERR_PTR(ret);
275			if (ret > 0)
276				break;
277			leaf = path->nodes[0];
278			nritems = btrfs_header_nritems(leaf);
279			continue;
280		}
281
282		btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
283		if (key.objectid != dirid || key.type != BTRFS_DIR_INDEX_KEY)
284			break;
285
286		di = btrfs_match_dir_item_name(root, path, name, name_len);
287		if (di)
288			return di;
289
290		path->slots[0]++;
291	}
292	return NULL;
293}
294
295struct btrfs_dir_item *btrfs_lookup_xattr(struct btrfs_trans_handle *trans,
296					  struct btrfs_root *root,
297					  struct btrfs_path *path, u64 dir,
298					  const char *name, u16 name_len,
299					  int mod)
300{
301	int ret;
302	struct btrfs_key key;
303	int ins_len = mod < 0 ? -1 : 0;
304	int cow = mod != 0;
305
306	key.objectid = dir;
307	btrfs_set_key_type(&key, BTRFS_XATTR_ITEM_KEY);
308	key.offset = btrfs_name_hash(name, name_len);
309	ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
310	if (ret < 0)
311		return ERR_PTR(ret);
312	if (ret > 0)
313		return NULL;
314
315	return btrfs_match_dir_item_name(root, path, name, name_len);
316}
317
318/*
319 * helper function to look at the directory item pointed to by 'path'
320 * this walks through all the entries in a dir item and finds one
321 * for a specific name.
322 */
323struct btrfs_dir_item *btrfs_match_dir_item_name(struct btrfs_root *root,
324			      struct btrfs_path *path,
325			      const char *name, int name_len)
326{
327	struct btrfs_dir_item *dir_item;
328	unsigned long name_ptr;
329	u32 total_len;
330	u32 cur = 0;
331	u32 this_len;
332	struct extent_buffer *leaf;
333
334	leaf = path->nodes[0];
335	dir_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dir_item);
336	if (verify_dir_item(root, leaf, dir_item))
337		return NULL;
338
339	total_len = btrfs_item_size_nr(leaf, path->slots[0]);
340	while (cur < total_len) {
341		this_len = sizeof(*dir_item) +
342			btrfs_dir_name_len(leaf, dir_item) +
343			btrfs_dir_data_len(leaf, dir_item);
344		name_ptr = (unsigned long)(dir_item + 1);
345
346		if (btrfs_dir_name_len(leaf, dir_item) == name_len &&
347		    memcmp_extent_buffer(leaf, name, name_ptr, name_len) == 0)
348			return dir_item;
349
350		cur += this_len;
351		dir_item = (struct btrfs_dir_item *)((char *)dir_item +
352						     this_len);
353	}
354	return NULL;
355}
356
357/*
358 * given a pointer into a directory item, delete it.  This
359 * handles items that have more than one entry in them.
360 */
361int btrfs_delete_one_dir_name(struct btrfs_trans_handle *trans,
362			      struct btrfs_root *root,
363			      struct btrfs_path *path,
364			      struct btrfs_dir_item *di)
365{
366
367	struct extent_buffer *leaf;
368	u32 sub_item_len;
369	u32 item_len;
370	int ret = 0;
371
372	leaf = path->nodes[0];
373	sub_item_len = sizeof(*di) + btrfs_dir_name_len(leaf, di) +
374		btrfs_dir_data_len(leaf, di);
375	item_len = btrfs_item_size_nr(leaf, path->slots[0]);
376	if (sub_item_len == item_len) {
377		ret = btrfs_del_item(trans, root, path);
378	} else {
379		/* MARKER */
380		unsigned long ptr = (unsigned long)di;
381		unsigned long start;
382
383		start = btrfs_item_ptr_offset(leaf, path->slots[0]);
384		memmove_extent_buffer(leaf, ptr, ptr + sub_item_len,
385			item_len - (ptr + sub_item_len - start));
386		ret = btrfs_truncate_item(trans, root, path,
387					  item_len - sub_item_len, 1);
388	}
389	return ret;
390}
391
392int verify_dir_item(struct btrfs_root *root,
393		    struct extent_buffer *leaf,
394		    struct btrfs_dir_item *dir_item)
395{
396	u16 namelen = BTRFS_NAME_LEN;
397	u8 type = btrfs_dir_type(leaf, dir_item);
398
399	if (type >= BTRFS_FT_MAX) {
400		printk(KERN_CRIT "btrfs: invalid dir item type: %d\n",
401		       (int)type);
402		return 1;
403	}
404
405	if (type == BTRFS_FT_XATTR)
406		namelen = XATTR_NAME_MAX;
407
408	if (btrfs_dir_name_len(leaf, dir_item) > namelen) {
409		printk(KERN_CRIT "btrfs: invalid dir item name len: %u\n",
410		       (unsigned)btrfs_dir_data_len(leaf, dir_item));
411		return 1;
412	}
413
414	/* BTRFS_MAX_XATTR_SIZE is the same for all dir items */
415	if (btrfs_dir_data_len(leaf, dir_item) > BTRFS_MAX_XATTR_SIZE(root)) {
416		printk(KERN_CRIT "btrfs: invalid dir item data len: %u\n",
417		       (unsigned)btrfs_dir_data_len(leaf, dir_item));
418		return 1;
419	}
420
421	return 0;
422}
423