1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (C) 2007 Oracle. All rights reserved.
4 */
5
6 #include "ctree.h"
7 #include "disk-io.h"
8 #include "transaction.h"
9 #include "print-tree.h"
10
btrfs_find_name_in_backref(struct extent_buffer * leaf,int slot,const char * name,int name_len)11 struct btrfs_inode_ref *btrfs_find_name_in_backref(struct extent_buffer *leaf,
12 int slot, const char *name,
13 int name_len)
14 {
15 struct btrfs_inode_ref *ref;
16 unsigned long ptr;
17 unsigned long name_ptr;
18 u32 item_size;
19 u32 cur_offset = 0;
20 int len;
21
22 item_size = btrfs_item_size_nr(leaf, slot);
23 ptr = btrfs_item_ptr_offset(leaf, slot);
24 while (cur_offset < item_size) {
25 ref = (struct btrfs_inode_ref *)(ptr + cur_offset);
26 len = btrfs_inode_ref_name_len(leaf, ref);
27 name_ptr = (unsigned long)(ref + 1);
28 cur_offset += len + sizeof(*ref);
29 if (len != name_len)
30 continue;
31 if (memcmp_extent_buffer(leaf, name, name_ptr, name_len) == 0)
32 return ref;
33 }
34 return NULL;
35 }
36
btrfs_find_name_in_ext_backref(struct extent_buffer * leaf,int slot,u64 ref_objectid,const char * name,int name_len)37 struct btrfs_inode_extref *btrfs_find_name_in_ext_backref(
38 struct extent_buffer *leaf, int slot, u64 ref_objectid,
39 const char *name, int name_len)
40 {
41 struct btrfs_inode_extref *extref;
42 unsigned long ptr;
43 unsigned long name_ptr;
44 u32 item_size;
45 u32 cur_offset = 0;
46 int ref_name_len;
47
48 item_size = btrfs_item_size_nr(leaf, slot);
49 ptr = btrfs_item_ptr_offset(leaf, slot);
50
51 /*
52 * Search all extended backrefs in this item. We're only
53 * looking through any collisions so most of the time this is
54 * just going to compare against one buffer. If all is well,
55 * we'll return success and the inode ref object.
56 */
57 while (cur_offset < item_size) {
58 extref = (struct btrfs_inode_extref *) (ptr + cur_offset);
59 name_ptr = (unsigned long)(&extref->name);
60 ref_name_len = btrfs_inode_extref_name_len(leaf, extref);
61
62 if (ref_name_len == name_len &&
63 btrfs_inode_extref_parent(leaf, extref) == ref_objectid &&
64 (memcmp_extent_buffer(leaf, name, name_ptr, name_len) == 0))
65 return extref;
66
67 cur_offset += ref_name_len + sizeof(*extref);
68 }
69 return NULL;
70 }
71
72 /* Returns NULL if no extref found */
73 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)74 btrfs_lookup_inode_extref(struct btrfs_trans_handle *trans,
75 struct btrfs_root *root,
76 struct btrfs_path *path,
77 const char *name, int name_len,
78 u64 inode_objectid, u64 ref_objectid, int ins_len,
79 int cow)
80 {
81 int ret;
82 struct btrfs_key key;
83
84 key.objectid = inode_objectid;
85 key.type = BTRFS_INODE_EXTREF_KEY;
86 key.offset = btrfs_extref_hash(ref_objectid, name, name_len);
87
88 ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
89 if (ret < 0)
90 return ERR_PTR(ret);
91 if (ret > 0)
92 return NULL;
93 return btrfs_find_name_in_ext_backref(path->nodes[0], path->slots[0],
94 ref_objectid, name, name_len);
95
96 }
97
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)98 static int btrfs_del_inode_extref(struct btrfs_trans_handle *trans,
99 struct btrfs_root *root,
100 const char *name, int name_len,
101 u64 inode_objectid, u64 ref_objectid,
102 u64 *index)
103 {
104 struct btrfs_path *path;
105 struct btrfs_key key;
106 struct btrfs_inode_extref *extref;
107 struct extent_buffer *leaf;
108 int ret;
109 int del_len = name_len + sizeof(*extref);
110 unsigned long ptr;
111 unsigned long item_start;
112 u32 item_size;
113
114 key.objectid = inode_objectid;
115 key.type = BTRFS_INODE_EXTREF_KEY;
116 key.offset = btrfs_extref_hash(ref_objectid, name, name_len);
117
118 path = btrfs_alloc_path();
119 if (!path)
120 return -ENOMEM;
121
122 path->leave_spinning = 1;
123
124 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
125 if (ret > 0)
126 ret = -ENOENT;
127 if (ret < 0)
128 goto out;
129
130 /*
131 * Sanity check - did we find the right item for this name?
132 * This should always succeed so error here will make the FS
133 * readonly.
134 */
135 extref = btrfs_find_name_in_ext_backref(path->nodes[0], path->slots[0],
136 ref_objectid, name, name_len);
137 if (!extref) {
138 btrfs_handle_fs_error(root->fs_info, -ENOENT, NULL);
139 ret = -EROFS;
140 goto out;
141 }
142
143 leaf = path->nodes[0];
144 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
145 if (index)
146 *index = btrfs_inode_extref_index(leaf, extref);
147
148 if (del_len == item_size) {
149 /*
150 * Common case only one ref in the item, remove the
151 * whole item.
152 */
153 ret = btrfs_del_item(trans, root, path);
154 goto out;
155 }
156
157 ptr = (unsigned long)extref;
158 item_start = btrfs_item_ptr_offset(leaf, path->slots[0]);
159
160 memmove_extent_buffer(leaf, ptr, ptr + del_len,
161 item_size - (ptr + del_len - item_start));
162
163 btrfs_truncate_item(path, item_size - del_len, 1);
164
165 out:
166 btrfs_free_path(path);
167
168 return ret;
169 }
170
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)171 int btrfs_del_inode_ref(struct btrfs_trans_handle *trans,
172 struct btrfs_root *root,
173 const char *name, int name_len,
174 u64 inode_objectid, u64 ref_objectid, u64 *index)
175 {
176 struct btrfs_path *path;
177 struct btrfs_key key;
178 struct btrfs_inode_ref *ref;
179 struct extent_buffer *leaf;
180 unsigned long ptr;
181 unsigned long item_start;
182 u32 item_size;
183 u32 sub_item_len;
184 int ret;
185 int search_ext_refs = 0;
186 int del_len = name_len + sizeof(*ref);
187
188 key.objectid = inode_objectid;
189 key.offset = ref_objectid;
190 key.type = BTRFS_INODE_REF_KEY;
191
192 path = btrfs_alloc_path();
193 if (!path)
194 return -ENOMEM;
195
196 path->leave_spinning = 1;
197
198 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
199 if (ret > 0) {
200 ret = -ENOENT;
201 search_ext_refs = 1;
202 goto out;
203 } else if (ret < 0) {
204 goto out;
205 }
206
207 ref = btrfs_find_name_in_backref(path->nodes[0], path->slots[0], name,
208 name_len);
209 if (!ref) {
210 ret = -ENOENT;
211 search_ext_refs = 1;
212 goto out;
213 }
214 leaf = path->nodes[0];
215 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
216
217 if (index)
218 *index = btrfs_inode_ref_index(leaf, ref);
219
220 if (del_len == item_size) {
221 ret = btrfs_del_item(trans, root, path);
222 goto out;
223 }
224 ptr = (unsigned long)ref;
225 sub_item_len = name_len + sizeof(*ref);
226 item_start = btrfs_item_ptr_offset(leaf, path->slots[0]);
227 memmove_extent_buffer(leaf, ptr, ptr + sub_item_len,
228 item_size - (ptr + sub_item_len - item_start));
229 btrfs_truncate_item(path, item_size - sub_item_len, 1);
230 out:
231 btrfs_free_path(path);
232
233 if (search_ext_refs) {
234 /*
235 * No refs were found, or we could not find the
236 * name in our ref array. Find and remove the extended
237 * inode ref then.
238 */
239 return btrfs_del_inode_extref(trans, root, name, name_len,
240 inode_objectid, ref_objectid, index);
241 }
242
243 return ret;
244 }
245
246 /*
247 * btrfs_insert_inode_extref() - Inserts an extended inode ref into a tree.
248 *
249 * The caller must have checked against BTRFS_LINK_MAX already.
250 */
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)251 static int btrfs_insert_inode_extref(struct btrfs_trans_handle *trans,
252 struct btrfs_root *root,
253 const char *name, int name_len,
254 u64 inode_objectid, u64 ref_objectid, u64 index)
255 {
256 struct btrfs_inode_extref *extref;
257 int ret;
258 int ins_len = name_len + sizeof(*extref);
259 unsigned long ptr;
260 struct btrfs_path *path;
261 struct btrfs_key key;
262 struct extent_buffer *leaf;
263 struct btrfs_item *item;
264
265 key.objectid = inode_objectid;
266 key.type = BTRFS_INODE_EXTREF_KEY;
267 key.offset = btrfs_extref_hash(ref_objectid, name, name_len);
268
269 path = btrfs_alloc_path();
270 if (!path)
271 return -ENOMEM;
272
273 path->leave_spinning = 1;
274 ret = btrfs_insert_empty_item(trans, root, path, &key,
275 ins_len);
276 if (ret == -EEXIST) {
277 if (btrfs_find_name_in_ext_backref(path->nodes[0],
278 path->slots[0],
279 ref_objectid,
280 name, name_len))
281 goto out;
282
283 btrfs_extend_item(path, ins_len);
284 ret = 0;
285 }
286 if (ret < 0)
287 goto out;
288
289 leaf = path->nodes[0];
290 item = btrfs_item_nr(path->slots[0]);
291 ptr = (unsigned long)btrfs_item_ptr(leaf, path->slots[0], char);
292 ptr += btrfs_item_size(leaf, item) - ins_len;
293 extref = (struct btrfs_inode_extref *)ptr;
294
295 btrfs_set_inode_extref_name_len(path->nodes[0], extref, name_len);
296 btrfs_set_inode_extref_index(path->nodes[0], extref, index);
297 btrfs_set_inode_extref_parent(path->nodes[0], extref, ref_objectid);
298
299 ptr = (unsigned long)&extref->name;
300 write_extent_buffer(path->nodes[0], name, ptr, name_len);
301 btrfs_mark_buffer_dirty(path->nodes[0]);
302
303 out:
304 btrfs_free_path(path);
305 return ret;
306 }
307
308 /* Will return 0, -ENOMEM, -EMLINK, or -EEXIST or anything from the CoW path */
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)309 int btrfs_insert_inode_ref(struct btrfs_trans_handle *trans,
310 struct btrfs_root *root,
311 const char *name, int name_len,
312 u64 inode_objectid, u64 ref_objectid, u64 index)
313 {
314 struct btrfs_fs_info *fs_info = root->fs_info;
315 struct btrfs_path *path;
316 struct btrfs_key key;
317 struct btrfs_inode_ref *ref;
318 unsigned long ptr;
319 int ret;
320 int ins_len = name_len + sizeof(*ref);
321
322 key.objectid = inode_objectid;
323 key.offset = ref_objectid;
324 key.type = BTRFS_INODE_REF_KEY;
325
326 path = btrfs_alloc_path();
327 if (!path)
328 return -ENOMEM;
329
330 path->leave_spinning = 1;
331 path->skip_release_on_error = 1;
332 ret = btrfs_insert_empty_item(trans, root, path, &key,
333 ins_len);
334 if (ret == -EEXIST) {
335 u32 old_size;
336 ref = btrfs_find_name_in_backref(path->nodes[0], path->slots[0],
337 name, name_len);
338 if (ref)
339 goto out;
340
341 old_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
342 btrfs_extend_item(path, ins_len);
343 ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
344 struct btrfs_inode_ref);
345 ref = (struct btrfs_inode_ref *)((unsigned long)ref + old_size);
346 btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
347 btrfs_set_inode_ref_index(path->nodes[0], ref, index);
348 ptr = (unsigned long)(ref + 1);
349 ret = 0;
350 } else if (ret < 0) {
351 if (ret == -EOVERFLOW) {
352 if (btrfs_find_name_in_backref(path->nodes[0],
353 path->slots[0],
354 name, name_len))
355 ret = -EEXIST;
356 else
357 ret = -EMLINK;
358 }
359 goto out;
360 } else {
361 ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
362 struct btrfs_inode_ref);
363 btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
364 btrfs_set_inode_ref_index(path->nodes[0], ref, index);
365 ptr = (unsigned long)(ref + 1);
366 }
367 write_extent_buffer(path->nodes[0], name, ptr, name_len);
368 btrfs_mark_buffer_dirty(path->nodes[0]);
369
370 out:
371 btrfs_free_path(path);
372
373 if (ret == -EMLINK) {
374 struct btrfs_super_block *disk_super = fs_info->super_copy;
375 /* We ran out of space in the ref array. Need to
376 * add an extended ref. */
377 if (btrfs_super_incompat_flags(disk_super)
378 & BTRFS_FEATURE_INCOMPAT_EXTENDED_IREF)
379 ret = btrfs_insert_inode_extref(trans, root, name,
380 name_len,
381 inode_objectid,
382 ref_objectid, index);
383 }
384
385 return ret;
386 }
387
btrfs_insert_empty_inode(struct btrfs_trans_handle * trans,struct btrfs_root * root,struct btrfs_path * path,u64 objectid)388 int btrfs_insert_empty_inode(struct btrfs_trans_handle *trans,
389 struct btrfs_root *root,
390 struct btrfs_path *path, u64 objectid)
391 {
392 struct btrfs_key key;
393 int ret;
394 key.objectid = objectid;
395 key.type = BTRFS_INODE_ITEM_KEY;
396 key.offset = 0;
397
398 ret = btrfs_insert_empty_item(trans, root, path, &key,
399 sizeof(struct btrfs_inode_item));
400 return ret;
401 }
402
btrfs_lookup_inode(struct btrfs_trans_handle * trans,struct btrfs_root * root,struct btrfs_path * path,struct btrfs_key * location,int mod)403 int btrfs_lookup_inode(struct btrfs_trans_handle *trans, struct btrfs_root
404 *root, struct btrfs_path *path,
405 struct btrfs_key *location, int mod)
406 {
407 int ins_len = mod < 0 ? -1 : 0;
408 int cow = mod != 0;
409 int ret;
410 int slot;
411 struct extent_buffer *leaf;
412 struct btrfs_key found_key;
413
414 ret = btrfs_search_slot(trans, root, location, path, ins_len, cow);
415 if (ret > 0 && location->type == BTRFS_ROOT_ITEM_KEY &&
416 location->offset == (u64)-1 && path->slots[0] != 0) {
417 slot = path->slots[0] - 1;
418 leaf = path->nodes[0];
419 btrfs_item_key_to_cpu(leaf, &found_key, slot);
420 if (found_key.objectid == location->objectid &&
421 found_key.type == location->type) {
422 path->slots[0]--;
423 return 0;
424 }
425 }
426 return ret;
427 }
428