Line data Source code
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 : #include "print-tree.h"
24 :
25 5060 : static int find_name_in_backref(struct btrfs_path *path, const char *name,
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 5060 : leaf = path->nodes[0];
37 5060 : item_size = btrfs_item_size_nr(leaf, path->slots[0]);
38 10120 : ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
39 199768 : while (cur_offset < item_size) {
40 198855 : ref = (struct btrfs_inode_ref *)(ptr + cur_offset);
41 198855 : len = btrfs_inode_ref_name_len(leaf, ref);
42 198855 : name_ptr = (unsigned long)(ref + 1);
43 198855 : cur_offset += len + sizeof(*ref);
44 198855 : if (len != name_len)
45 738 : continue;
46 198117 : if (memcmp_extent_buffer(leaf, name, name_ptr, name_len) == 0) {
47 4147 : *ref_ret = ref;
48 : return 1;
49 : }
50 : }
51 : return 0;
52 : }
53 :
54 1927 : 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 1927 : leaf = path->nodes[0];
67 1927 : item_size = btrfs_item_size_nr(leaf, path->slots[0]);
68 3854 : 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 3854 : while (cur_offset < item_size) {
77 1927 : extref = (struct btrfs_inode_extref *) (ptr + cur_offset);
78 1927 : name_ptr = (unsigned long)(&extref->name);
79 1927 : ref_name_len = btrfs_inode_extref_name_len(leaf, extref);
80 :
81 3854 : if (ref_name_len == name_len &&
82 1927 : btrfs_inode_extref_parent(leaf, extref) == ref_objectid &&
83 1927 : (memcmp_extent_buffer(leaf, name, name_ptr, name_len) == 0)) {
84 1927 : if (extref_ret)
85 1927 : *extref_ret = extref;
86 : return 1;
87 : }
88 :
89 0 : cur_offset += ref_name_len + sizeof(*extref);
90 : }
91 : return 0;
92 : }
93 :
94 : /* Returns NULL if no extref found */
95 : struct btrfs_inode_extref *
96 0 : btrfs_lookup_inode_extref(struct btrfs_trans_handle *trans,
97 : struct btrfs_root *root,
98 : struct btrfs_path *path,
99 : const char *name, int name_len,
100 : u64 inode_objectid, u64 ref_objectid, int ins_len,
101 : int cow)
102 : {
103 : int ret;
104 : struct btrfs_key key;
105 : struct btrfs_inode_extref *extref;
106 :
107 0 : key.objectid = inode_objectid;
108 0 : key.type = BTRFS_INODE_EXTREF_KEY;
109 0 : key.offset = btrfs_extref_hash(ref_objectid, name, name_len);
110 :
111 0 : ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
112 0 : if (ret < 0)
113 0 : return ERR_PTR(ret);
114 0 : if (ret > 0)
115 : return NULL;
116 0 : if (!btrfs_find_name_in_ext_backref(path, ref_objectid, name, name_len, &extref))
117 : return NULL;
118 0 : return extref;
119 : }
120 :
121 1935 : static int btrfs_del_inode_extref(struct btrfs_trans_handle *trans,
122 : struct btrfs_root *root,
123 : const char *name, int name_len,
124 : u64 inode_objectid, u64 ref_objectid,
125 : u64 *index)
126 : {
127 : struct btrfs_path *path;
128 : struct btrfs_key key;
129 : struct btrfs_inode_extref *extref;
130 : struct extent_buffer *leaf;
131 : int ret;
132 1935 : int del_len = name_len + sizeof(*extref);
133 : unsigned long ptr;
134 : unsigned long item_start;
135 : u32 item_size;
136 :
137 1935 : key.objectid = inode_objectid;
138 : btrfs_set_key_type(&key, BTRFS_INODE_EXTREF_KEY);
139 1935 : key.offset = btrfs_extref_hash(ref_objectid, name, name_len);
140 :
141 1935 : path = btrfs_alloc_path();
142 1935 : if (!path)
143 : return -ENOMEM;
144 :
145 1935 : path->leave_spinning = 1;
146 :
147 1935 : ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
148 1935 : if (ret > 0)
149 : ret = -ENOENT;
150 1935 : if (ret < 0)
151 : goto out;
152 :
153 : /*
154 : * Sanity check - did we find the right item for this name?
155 : * This should always succeed so error here will make the FS
156 : * readonly.
157 : */
158 1927 : if (!btrfs_find_name_in_ext_backref(path, ref_objectid,
159 : name, name_len, &extref)) {
160 0 : btrfs_std_error(root->fs_info, -ENOENT);
161 : ret = -EROFS;
162 0 : goto out;
163 : }
164 :
165 1927 : leaf = path->nodes[0];
166 1927 : item_size = btrfs_item_size_nr(leaf, path->slots[0]);
167 1927 : if (index)
168 3854 : *index = btrfs_inode_extref_index(leaf, extref);
169 :
170 1927 : if (del_len == item_size) {
171 : /*
172 : * Common case only one ref in the item, remove the
173 : * whole item.
174 : */
175 : ret = btrfs_del_item(trans, root, path);
176 1927 : goto out;
177 : }
178 :
179 0 : ptr = (unsigned long)extref;
180 0 : item_start = btrfs_item_ptr_offset(leaf, path->slots[0]);
181 :
182 0 : memmove_extent_buffer(leaf, ptr, ptr + del_len,
183 0 : item_size - (ptr + del_len - item_start));
184 :
185 0 : btrfs_truncate_item(root, path, item_size - del_len, 1);
186 :
187 : out:
188 1935 : btrfs_free_path(path);
189 :
190 1935 : return ret;
191 : }
192 :
193 6082 : int btrfs_del_inode_ref(struct btrfs_trans_handle *trans,
194 : struct btrfs_root *root,
195 : const char *name, int name_len,
196 : u64 inode_objectid, u64 ref_objectid, u64 *index)
197 : {
198 4147 : struct btrfs_path *path;
199 : struct btrfs_key key;
200 : struct btrfs_inode_ref *ref;
201 : struct extent_buffer *leaf;
202 : unsigned long ptr;
203 : unsigned long item_start;
204 : u32 item_size;
205 : u32 sub_item_len;
206 : int ret;
207 : int search_ext_refs = 0;
208 6082 : int del_len = name_len + sizeof(*ref);
209 :
210 6082 : key.objectid = inode_objectid;
211 6082 : key.offset = ref_objectid;
212 : btrfs_set_key_type(&key, BTRFS_INODE_REF_KEY);
213 :
214 6082 : path = btrfs_alloc_path();
215 6082 : if (!path)
216 : return -ENOMEM;
217 :
218 6082 : path->leave_spinning = 1;
219 :
220 6082 : ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
221 6082 : if (ret > 0) {
222 : ret = -ENOENT;
223 : search_ext_refs = 1;
224 : goto out;
225 4147 : } else if (ret < 0) {
226 : goto out;
227 : }
228 4147 : if (!find_name_in_backref(path, name, name_len, &ref)) {
229 : ret = -ENOENT;
230 : search_ext_refs = 1;
231 : goto out;
232 : }
233 4147 : leaf = path->nodes[0];
234 4147 : item_size = btrfs_item_size_nr(leaf, path->slots[0]);
235 :
236 4147 : if (index)
237 8294 : *index = btrfs_inode_ref_index(leaf, ref);
238 :
239 4147 : if (del_len == item_size) {
240 : ret = btrfs_del_item(trans, root, path);
241 3243 : goto out;
242 : }
243 904 : ptr = (unsigned long)ref;
244 : sub_item_len = name_len + sizeof(*ref);
245 1808 : item_start = btrfs_item_ptr_offset(leaf, path->slots[0]);
246 1808 : memmove_extent_buffer(leaf, ptr, ptr + sub_item_len,
247 904 : item_size - (ptr + sub_item_len - item_start));
248 904 : btrfs_truncate_item(root, path, item_size - sub_item_len, 1);
249 : out:
250 6082 : btrfs_free_path(path);
251 :
252 6082 : if (search_ext_refs) {
253 : /*
254 : * No refs were found, or we could not find the
255 : * name in our ref array. Find and remove the extended
256 : * inode ref then.
257 : */
258 1935 : return btrfs_del_inode_extref(trans, root, name, name_len,
259 : inode_objectid, ref_objectid, index);
260 : }
261 :
262 : return ret;
263 : }
264 :
265 : /*
266 : * btrfs_insert_inode_extref() - Inserts an extended inode ref into a tree.
267 : *
268 : * The caller must have checked against BTRFS_LINK_MAX already.
269 : */
270 1928 : static int btrfs_insert_inode_extref(struct btrfs_trans_handle *trans,
271 : struct btrfs_root *root,
272 : const char *name, int name_len,
273 : u64 inode_objectid, u64 ref_objectid, u64 index)
274 : {
275 : struct btrfs_inode_extref *extref;
276 : int ret;
277 1928 : int ins_len = name_len + sizeof(*extref);
278 : unsigned long ptr;
279 : struct btrfs_path *path;
280 : struct btrfs_key key;
281 : struct extent_buffer *leaf;
282 : struct btrfs_item *item;
283 :
284 1928 : key.objectid = inode_objectid;
285 1928 : key.type = BTRFS_INODE_EXTREF_KEY;
286 1928 : key.offset = btrfs_extref_hash(ref_objectid, name, name_len);
287 :
288 1928 : path = btrfs_alloc_path();
289 1928 : if (!path)
290 : return -ENOMEM;
291 :
292 1928 : path->leave_spinning = 1;
293 : ret = btrfs_insert_empty_item(trans, root, path, &key,
294 : ins_len);
295 1928 : if (ret == -EEXIST) {
296 0 : if (btrfs_find_name_in_ext_backref(path, ref_objectid,
297 : name, name_len, NULL))
298 : goto out;
299 :
300 0 : btrfs_extend_item(root, path, ins_len);
301 : ret = 0;
302 : }
303 1928 : if (ret < 0)
304 : goto out;
305 :
306 1928 : leaf = path->nodes[0];
307 1928 : item = btrfs_item_nr(path->slots[0]);
308 1928 : ptr = (unsigned long)btrfs_item_ptr(leaf, path->slots[0], char);
309 1928 : ptr += btrfs_item_size(leaf, item) - ins_len;
310 1928 : extref = (struct btrfs_inode_extref *)ptr;
311 :
312 1928 : btrfs_set_inode_extref_name_len(path->nodes[0], extref, name_len);
313 1928 : btrfs_set_inode_extref_index(path->nodes[0], extref, index);
314 1928 : btrfs_set_inode_extref_parent(path->nodes[0], extref, ref_objectid);
315 :
316 1928 : ptr = (unsigned long)&extref->name;
317 1928 : write_extent_buffer(path->nodes[0], name, ptr, name_len);
318 1928 : btrfs_mark_buffer_dirty(path->nodes[0]);
319 :
320 : out:
321 1928 : btrfs_free_path(path);
322 1928 : return ret;
323 : }
324 :
325 : /* Will return 0, -ENOMEM, -EMLINK, or -EEXIST or anything from the CoW path */
326 5884 : int btrfs_insert_inode_ref(struct btrfs_trans_handle *trans,
327 : struct btrfs_root *root,
328 : const char *name, int name_len,
329 : u64 inode_objectid, u64 ref_objectid, u64 index)
330 : {
331 913 : struct btrfs_path *path;
332 : struct btrfs_key key;
333 : struct btrfs_inode_ref *ref;
334 : unsigned long ptr;
335 : int ret;
336 5884 : int ins_len = name_len + sizeof(*ref);
337 :
338 5884 : key.objectid = inode_objectid;
339 5884 : key.offset = ref_objectid;
340 : btrfs_set_key_type(&key, BTRFS_INODE_REF_KEY);
341 :
342 5884 : path = btrfs_alloc_path();
343 5884 : if (!path)
344 : return -ENOMEM;
345 :
346 5884 : path->leave_spinning = 1;
347 : ret = btrfs_insert_empty_item(trans, root, path, &key,
348 : ins_len);
349 5884 : if (ret == -EEXIST) {
350 : u32 old_size;
351 :
352 913 : if (find_name_in_backref(path, name, name_len, &ref))
353 : goto out;
354 :
355 913 : old_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
356 913 : btrfs_extend_item(root, path, ins_len);
357 1826 : ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
358 : struct btrfs_inode_ref);
359 913 : ref = (struct btrfs_inode_ref *)((unsigned long)ref + old_size);
360 913 : btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
361 913 : btrfs_set_inode_ref_index(path->nodes[0], ref, index);
362 913 : ptr = (unsigned long)(ref + 1);
363 : ret = 0;
364 4971 : } else if (ret < 0) {
365 1928 : if (ret == -EOVERFLOW)
366 : ret = -EMLINK;
367 : goto out;
368 : } else {
369 6086 : ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
370 : struct btrfs_inode_ref);
371 3043 : btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
372 3043 : btrfs_set_inode_ref_index(path->nodes[0], ref, index);
373 3043 : ptr = (unsigned long)(ref + 1);
374 : }
375 3956 : write_extent_buffer(path->nodes[0], name, ptr, name_len);
376 3956 : btrfs_mark_buffer_dirty(path->nodes[0]);
377 :
378 : out:
379 5884 : btrfs_free_path(path);
380 :
381 5884 : if (ret == -EMLINK) {
382 1928 : struct btrfs_super_block *disk_super = root->fs_info->super_copy;
383 : /* We ran out of space in the ref array. Need to
384 : * add an extended ref. */
385 1928 : if (btrfs_super_incompat_flags(disk_super)
386 1928 : & BTRFS_FEATURE_INCOMPAT_EXTENDED_IREF)
387 1928 : ret = btrfs_insert_inode_extref(trans, root, name,
388 : name_len,
389 : inode_objectid,
390 : ref_objectid, index);
391 : }
392 :
393 5884 : return ret;
394 : }
395 :
396 251 : int btrfs_insert_empty_inode(struct btrfs_trans_handle *trans,
397 : struct btrfs_root *root,
398 : struct btrfs_path *path, u64 objectid)
399 : {
400 : struct btrfs_key key;
401 : int ret;
402 251 : key.objectid = objectid;
403 : btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
404 251 : key.offset = 0;
405 :
406 : ret = btrfs_insert_empty_item(trans, root, path, &key,
407 : sizeof(struct btrfs_inode_item));
408 251 : return ret;
409 : }
410 :
411 86132 : int btrfs_lookup_inode(struct btrfs_trans_handle *trans, struct btrfs_root
412 : *root, struct btrfs_path *path,
413 72 : struct btrfs_key *location, int mod)
414 : {
415 86132 : int ins_len = mod < 0 ? -1 : 0;
416 86132 : int cow = mod != 0;
417 : int ret;
418 : int slot;
419 : struct extent_buffer *leaf;
420 : struct btrfs_key found_key;
421 :
422 86132 : ret = btrfs_search_slot(trans, root, location, path, ins_len, cow);
423 86171 : if (ret > 0 && btrfs_key_type(location) == BTRFS_ROOT_ITEM_KEY &&
424 0 : location->offset == (u64)-1 && path->slots[0] != 0) {
425 0 : slot = path->slots[0] - 1;
426 0 : leaf = path->nodes[0];
427 0 : btrfs_item_key_to_cpu(leaf, &found_key, slot);
428 0 : if (found_key.objectid == location->objectid &&
429 0 : btrfs_key_type(&found_key) == btrfs_key_type(location)) {
430 0 : path->slots[0]--;
431 0 : return 0;
432 : }
433 : }
434 86099 : return ret;
435 : }
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