1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright (C) 2007 Oracle. All rights reserved.
8 #include "transaction.h"
11 * insert a name into a directory, doing overflow properly if there is a hash
12 * collision. data_size indicates how big the item inserted should be. On
13 * success a struct btrfs_dir_item pointer is returned, otherwise it is
16 * The name is not copied into the dir item, you have to do that yourself.
18 static struct btrfs_dir_item *insert_with_overflow(struct btrfs_trans_handle
20 struct btrfs_root *root,
21 struct btrfs_path *path,
22 struct btrfs_key *cpu_key,
27 struct btrfs_fs_info *fs_info = root->fs_info;
30 struct btrfs_item *item;
31 struct extent_buffer *leaf;
33 ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
35 struct btrfs_dir_item *di;
36 di = btrfs_match_dir_item_name(fs_info, path, name, name_len);
38 return ERR_PTR(-EEXIST);
39 btrfs_extend_item(path, data_size);
43 leaf = path->nodes[0];
44 item = btrfs_item_nr(path->slots[0]);
45 ptr = btrfs_item_ptr(leaf, path->slots[0], char);
46 BUG_ON(data_size > btrfs_item_size(leaf, item));
47 ptr += btrfs_item_size(leaf, item) - data_size;
48 return (struct btrfs_dir_item *)ptr;
52 * xattrs work a lot like directories, this inserts an xattr item
55 int btrfs_insert_xattr_item(struct btrfs_trans_handle *trans,
56 struct btrfs_root *root,
57 struct btrfs_path *path, u64 objectid,
58 const char *name, u16 name_len,
59 const void *data, u16 data_len)
62 struct btrfs_dir_item *dir_item;
63 unsigned long name_ptr, data_ptr;
64 struct btrfs_key key, location;
65 struct btrfs_disk_key disk_key;
66 struct extent_buffer *leaf;
69 if (name_len + data_len > BTRFS_MAX_XATTR_SIZE(root->fs_info))
72 key.objectid = objectid;
73 key.type = BTRFS_XATTR_ITEM_KEY;
74 key.offset = btrfs_name_hash(name, name_len);
76 data_size = sizeof(*dir_item) + name_len + data_len;
77 dir_item = insert_with_overflow(trans, root, path, &key, data_size,
80 return PTR_ERR(dir_item);
81 memset(&location, 0, sizeof(location));
83 leaf = path->nodes[0];
84 btrfs_cpu_key_to_disk(&disk_key, &location);
85 btrfs_set_dir_item_key(leaf, dir_item, &disk_key);
86 btrfs_set_dir_type(leaf, dir_item, BTRFS_FT_XATTR);
87 btrfs_set_dir_name_len(leaf, dir_item, name_len);
88 btrfs_set_dir_transid(leaf, dir_item, trans->transid);
89 btrfs_set_dir_data_len(leaf, dir_item, data_len);
90 name_ptr = (unsigned long)(dir_item + 1);
91 data_ptr = (unsigned long)((char *)name_ptr + name_len);
93 write_extent_buffer(leaf, name, name_ptr, name_len);
94 write_extent_buffer(leaf, data, data_ptr, data_len);
95 btrfs_mark_buffer_dirty(path->nodes[0]);
101 * insert a directory item in the tree, doing all the magic for
102 * both indexes. 'dir' indicates which objectid to insert it into,
103 * 'location' is the key to stuff into the directory item, 'type' is the
104 * type of the inode we're pointing to, and 'index' is the sequence number
105 * to use for the second index (if one is created).
106 * Will return 0 or -ENOMEM
108 int btrfs_insert_dir_item(struct btrfs_trans_handle *trans, const char *name,
109 int name_len, struct btrfs_inode *dir,
110 struct btrfs_key *location, u8 type, u64 index)
114 struct btrfs_root *root = dir->root;
115 struct btrfs_path *path;
116 struct btrfs_dir_item *dir_item;
117 struct extent_buffer *leaf;
118 unsigned long name_ptr;
119 struct btrfs_key key;
120 struct btrfs_disk_key disk_key;
123 key.objectid = btrfs_ino(dir);
124 key.type = BTRFS_DIR_ITEM_KEY;
125 key.offset = btrfs_name_hash(name, name_len);
127 path = btrfs_alloc_path();
130 path->leave_spinning = 1;
132 btrfs_cpu_key_to_disk(&disk_key, location);
134 data_size = sizeof(*dir_item) + name_len;
135 dir_item = insert_with_overflow(trans, root, path, &key, data_size,
137 if (IS_ERR(dir_item)) {
138 ret = PTR_ERR(dir_item);
144 leaf = path->nodes[0];
145 btrfs_set_dir_item_key(leaf, dir_item, &disk_key);
146 btrfs_set_dir_type(leaf, dir_item, type);
147 btrfs_set_dir_data_len(leaf, dir_item, 0);
148 btrfs_set_dir_name_len(leaf, dir_item, name_len);
149 btrfs_set_dir_transid(leaf, dir_item, trans->transid);
150 name_ptr = (unsigned long)(dir_item + 1);
152 write_extent_buffer(leaf, name, name_ptr, name_len);
153 btrfs_mark_buffer_dirty(leaf);
156 /* FIXME, use some real flag for selecting the extra index */
157 if (root == root->fs_info->tree_root) {
161 btrfs_release_path(path);
163 ret2 = btrfs_insert_delayed_dir_index(trans, name, name_len, dir,
164 &disk_key, type, index);
166 btrfs_free_path(path);
174 static struct btrfs_dir_item *btrfs_lookup_match_dir(
175 struct btrfs_trans_handle *trans,
176 struct btrfs_root *root, struct btrfs_path *path,
177 struct btrfs_key *key, const char *name,
178 int name_len, int mod)
180 const int ins_len = (mod < 0 ? -1 : 0);
181 const int cow = (mod != 0);
184 ret = btrfs_search_slot(trans, root, key, path, ins_len, cow);
188 return ERR_PTR(-ENOENT);
190 return btrfs_match_dir_item_name(root->fs_info, path, name, name_len);
194 * Lookup for a directory item by name.
196 * @trans: The transaction handle to use. Can be NULL if @mod is 0.
197 * @root: The root of the target tree.
198 * @path: Path to use for the search.
199 * @dir: The inode number (objectid) of the directory.
200 * @name: The name associated to the directory entry we are looking for.
201 * @name_len: The length of the name.
202 * @mod: Used to indicate if the tree search is meant for a read only
203 * lookup, for a modification lookup or for a deletion lookup, so
204 * its value should be 0, 1 or -1, respectively.
206 * Returns: NULL if the dir item does not exists, an error pointer if an error
207 * happened, or a pointer to a dir item if a dir item exists for the given name.
209 struct btrfs_dir_item *btrfs_lookup_dir_item(struct btrfs_trans_handle *trans,
210 struct btrfs_root *root,
211 struct btrfs_path *path, u64 dir,
212 const char *name, int name_len,
215 struct btrfs_key key;
216 struct btrfs_dir_item *di;
219 key.type = BTRFS_DIR_ITEM_KEY;
220 key.offset = btrfs_name_hash(name, name_len);
222 di = btrfs_lookup_match_dir(trans, root, path, &key, name, name_len, mod);
223 if (IS_ERR(di) && PTR_ERR(di) == -ENOENT)
229 int btrfs_check_dir_item_collision(struct btrfs_root *root, u64 dir,
230 const char *name, int name_len)
233 struct btrfs_key key;
234 struct btrfs_dir_item *di;
236 struct extent_buffer *leaf;
238 struct btrfs_path *path;
240 path = btrfs_alloc_path();
245 key.type = BTRFS_DIR_ITEM_KEY;
246 key.offset = btrfs_name_hash(name, name_len);
248 di = btrfs_lookup_match_dir(NULL, root, path, &key, name, name_len, 0);
251 /* Nothing found, we're safe */
252 if (ret == -ENOENT) {
261 /* we found an item, look for our name in the item */
263 /* our exact name was found */
269 * see if there is room in the item to insert this
272 data_size = sizeof(*di) + name_len;
273 leaf = path->nodes[0];
274 slot = path->slots[0];
275 if (data_size + btrfs_item_size_nr(leaf, slot) +
276 sizeof(struct btrfs_item) > BTRFS_LEAF_DATA_SIZE(root->fs_info)) {
279 /* plenty of insertion room */
283 btrfs_free_path(path);
288 * Lookup for a directory index item by name and index number.
290 * @trans: The transaction handle to use. Can be NULL if @mod is 0.
291 * @root: The root of the target tree.
292 * @path: Path to use for the search.
293 * @dir: The inode number (objectid) of the directory.
294 * @index: The index number.
295 * @name: The name associated to the directory entry we are looking for.
296 * @name_len: The length of the name.
297 * @mod: Used to indicate if the tree search is meant for a read only
298 * lookup, for a modification lookup or for a deletion lookup, so
299 * its value should be 0, 1 or -1, respectively.
301 * Returns: NULL if the dir index item does not exists, an error pointer if an
302 * error happened, or a pointer to a dir item if the dir index item exists and
303 * matches the criteria (name and index number).
305 struct btrfs_dir_item *
306 btrfs_lookup_dir_index_item(struct btrfs_trans_handle *trans,
307 struct btrfs_root *root,
308 struct btrfs_path *path, u64 dir,
309 u64 index, const char *name, int name_len,
312 struct btrfs_dir_item *di;
313 struct btrfs_key key;
316 key.type = BTRFS_DIR_INDEX_KEY;
319 di = btrfs_lookup_match_dir(trans, root, path, &key, name, name_len, mod);
320 if (di == ERR_PTR(-ENOENT))
326 struct btrfs_dir_item *
327 btrfs_search_dir_index_item(struct btrfs_root *root,
328 struct btrfs_path *path, u64 dirid,
329 const char *name, int name_len)
331 struct extent_buffer *leaf;
332 struct btrfs_dir_item *di;
333 struct btrfs_key key;
337 key.objectid = dirid;
338 key.type = BTRFS_DIR_INDEX_KEY;
341 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
345 leaf = path->nodes[0];
346 nritems = btrfs_header_nritems(leaf);
349 if (path->slots[0] >= nritems) {
350 ret = btrfs_next_leaf(root, path);
355 leaf = path->nodes[0];
356 nritems = btrfs_header_nritems(leaf);
360 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
361 if (key.objectid != dirid || key.type != BTRFS_DIR_INDEX_KEY)
364 di = btrfs_match_dir_item_name(root->fs_info, path,
374 struct btrfs_dir_item *btrfs_lookup_xattr(struct btrfs_trans_handle *trans,
375 struct btrfs_root *root,
376 struct btrfs_path *path, u64 dir,
377 const char *name, u16 name_len,
380 struct btrfs_key key;
381 struct btrfs_dir_item *di;
384 key.type = BTRFS_XATTR_ITEM_KEY;
385 key.offset = btrfs_name_hash(name, name_len);
387 di = btrfs_lookup_match_dir(trans, root, path, &key, name, name_len, mod);
388 if (IS_ERR(di) && PTR_ERR(di) == -ENOENT)
395 * helper function to look at the directory item pointed to by 'path'
396 * this walks through all the entries in a dir item and finds one
397 * for a specific name.
399 struct btrfs_dir_item *btrfs_match_dir_item_name(struct btrfs_fs_info *fs_info,
400 struct btrfs_path *path,
401 const char *name, int name_len)
403 struct btrfs_dir_item *dir_item;
404 unsigned long name_ptr;
408 struct extent_buffer *leaf;
410 leaf = path->nodes[0];
411 dir_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dir_item);
413 total_len = btrfs_item_size_nr(leaf, path->slots[0]);
414 while (cur < total_len) {
415 this_len = sizeof(*dir_item) +
416 btrfs_dir_name_len(leaf, dir_item) +
417 btrfs_dir_data_len(leaf, dir_item);
418 name_ptr = (unsigned long)(dir_item + 1);
420 if (btrfs_dir_name_len(leaf, dir_item) == name_len &&
421 memcmp_extent_buffer(leaf, name, name_ptr, name_len) == 0)
425 dir_item = (struct btrfs_dir_item *)((char *)dir_item +
432 * given a pointer into a directory item, delete it. This
433 * handles items that have more than one entry in them.
435 int btrfs_delete_one_dir_name(struct btrfs_trans_handle *trans,
436 struct btrfs_root *root,
437 struct btrfs_path *path,
438 struct btrfs_dir_item *di)
441 struct extent_buffer *leaf;
446 leaf = path->nodes[0];
447 sub_item_len = sizeof(*di) + btrfs_dir_name_len(leaf, di) +
448 btrfs_dir_data_len(leaf, di);
449 item_len = btrfs_item_size_nr(leaf, path->slots[0]);
450 if (sub_item_len == item_len) {
451 ret = btrfs_del_item(trans, root, path);
454 unsigned long ptr = (unsigned long)di;
457 start = btrfs_item_ptr_offset(leaf, path->slots[0]);
458 memmove_extent_buffer(leaf, ptr, ptr + sub_item_len,
459 item_len - (ptr + sub_item_len - start));
460 btrfs_truncate_item(path, item_len - sub_item_len, 1);