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-rw-r--r--fs/btrfs/root-tree.c366
1 files changed, 366 insertions, 0 deletions
diff --git a/fs/btrfs/root-tree.c b/fs/btrfs/root-tree.c
new file mode 100644
index 000000000000..b48650de4472
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+++ b/fs/btrfs/root-tree.c
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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 "transaction.h"
21#include "disk-io.h"
22#include "print-tree.h"
23
24/*
25 * search forward for a root, starting with objectid 'search_start'
26 * if a root key is found, the objectid we find is filled into 'found_objectid'
27 * and 0 is returned. < 0 is returned on error, 1 if there is nothing
28 * left in the tree.
29 */
30int btrfs_search_root(struct btrfs_root *root, u64 search_start,
31 u64 *found_objectid)
32{
33 struct btrfs_path *path;
34 struct btrfs_key search_key;
35 int ret;
36
37 root = root->fs_info->tree_root;
38 search_key.objectid = search_start;
39 search_key.type = (u8)-1;
40 search_key.offset = (u64)-1;
41
42 path = btrfs_alloc_path();
43 BUG_ON(!path);
44again:
45 ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0);
46 if (ret < 0)
47 goto out;
48 if (ret == 0) {
49 ret = 1;
50 goto out;
51 }
52 if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) {
53 ret = btrfs_next_leaf(root, path);
54 if (ret)
55 goto out;
56 }
57 btrfs_item_key_to_cpu(path->nodes[0], &search_key, path->slots[0]);
58 if (search_key.type != BTRFS_ROOT_ITEM_KEY) {
59 search_key.offset++;
60 btrfs_release_path(root, path);
61 goto again;
62 }
63 ret = 0;
64 *found_objectid = search_key.objectid;
65
66out:
67 btrfs_free_path(path);
68 return ret;
69}
70
71/*
72 * lookup the root with the highest offset for a given objectid. The key we do
73 * find is copied into 'key'. If we find something return 0, otherwise 1, < 0
74 * on error.
75 */
76int btrfs_find_last_root(struct btrfs_root *root, u64 objectid,
77 struct btrfs_root_item *item, struct btrfs_key *key)
78{
79 struct btrfs_path *path;
80 struct btrfs_key search_key;
81 struct btrfs_key found_key;
82 struct extent_buffer *l;
83 int ret;
84 int slot;
85
86 search_key.objectid = objectid;
87 search_key.type = BTRFS_ROOT_ITEM_KEY;
88 search_key.offset = (u64)-1;
89
90 path = btrfs_alloc_path();
91 BUG_ON(!path);
92 ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0);
93 if (ret < 0)
94 goto out;
95
96 BUG_ON(ret == 0);
97 l = path->nodes[0];
98 BUG_ON(path->slots[0] == 0);
99 slot = path->slots[0] - 1;
100 btrfs_item_key_to_cpu(l, &found_key, slot);
101 if (found_key.objectid != objectid) {
102 ret = 1;
103 goto out;
104 }
105 read_extent_buffer(l, item, btrfs_item_ptr_offset(l, slot),
106 sizeof(*item));
107 memcpy(key, &found_key, sizeof(found_key));
108 ret = 0;
109out:
110 btrfs_free_path(path);
111 return ret;
112}
113
114/*
115 * copy the data in 'item' into the btree
116 */
117int btrfs_update_root(struct btrfs_trans_handle *trans, struct btrfs_root
118 *root, struct btrfs_key *key, struct btrfs_root_item
119 *item)
120{
121 struct btrfs_path *path;
122 struct extent_buffer *l;
123 int ret;
124 int slot;
125 unsigned long ptr;
126
127 path = btrfs_alloc_path();
128 BUG_ON(!path);
129 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
130 if (ret < 0)
131 goto out;
132
133 if (ret != 0) {
134 btrfs_print_leaf(root, path->nodes[0]);
135 printk(KERN_CRIT "unable to update root key %llu %u %llu\n",
136 (unsigned long long)key->objectid, key->type,
137 (unsigned long long)key->offset);
138 BUG_ON(1);
139 }
140
141 l = path->nodes[0];
142 slot = path->slots[0];
143 ptr = btrfs_item_ptr_offset(l, slot);
144 write_extent_buffer(l, item, ptr, sizeof(*item));
145 btrfs_mark_buffer_dirty(path->nodes[0]);
146out:
147 btrfs_release_path(root, path);
148 btrfs_free_path(path);
149 return ret;
150}
151
152int btrfs_insert_root(struct btrfs_trans_handle *trans, struct btrfs_root
153 *root, struct btrfs_key *key, struct btrfs_root_item
154 *item)
155{
156 int ret;
157 ret = btrfs_insert_item(trans, root, key, item, sizeof(*item));
158 return ret;
159}
160
161/*
162 * at mount time we want to find all the old transaction snapshots that were in
163 * the process of being deleted if we crashed. This is any root item with an
164 * offset lower than the latest root. They need to be queued for deletion to
165 * finish what was happening when we crashed.
166 */
167int btrfs_find_dead_roots(struct btrfs_root *root, u64 objectid,
168 struct btrfs_root *latest)
169{
170 struct btrfs_root *dead_root;
171 struct btrfs_item *item;
172 struct btrfs_root_item *ri;
173 struct btrfs_key key;
174 struct btrfs_key found_key;
175 struct btrfs_path *path;
176 int ret;
177 u32 nritems;
178 struct extent_buffer *leaf;
179 int slot;
180
181 key.objectid = objectid;
182 btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
183 key.offset = 0;
184 path = btrfs_alloc_path();
185 if (!path)
186 return -ENOMEM;
187
188again:
189 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
190 if (ret < 0)
191 goto err;
192 while (1) {
193 leaf = path->nodes[0];
194 nritems = btrfs_header_nritems(leaf);
195 slot = path->slots[0];
196 if (slot >= nritems) {
197 ret = btrfs_next_leaf(root, path);
198 if (ret)
199 break;
200 leaf = path->nodes[0];
201 nritems = btrfs_header_nritems(leaf);
202 slot = path->slots[0];
203 }
204 item = btrfs_item_nr(leaf, slot);
205 btrfs_item_key_to_cpu(leaf, &key, slot);
206 if (btrfs_key_type(&key) != BTRFS_ROOT_ITEM_KEY)
207 goto next;
208
209 if (key.objectid < objectid)
210 goto next;
211
212 if (key.objectid > objectid)
213 break;
214
215 ri = btrfs_item_ptr(leaf, slot, struct btrfs_root_item);
216 if (btrfs_disk_root_refs(leaf, ri) != 0)
217 goto next;
218
219 memcpy(&found_key, &key, sizeof(key));
220 key.offset++;
221 btrfs_release_path(root, path);
222 dead_root =
223 btrfs_read_fs_root_no_radix(root->fs_info->tree_root,
224 &found_key);
225 if (IS_ERR(dead_root)) {
226 ret = PTR_ERR(dead_root);
227 goto err;
228 }
229
230 if (objectid == BTRFS_TREE_RELOC_OBJECTID)
231 ret = btrfs_add_dead_reloc_root(dead_root);
232 else
233 ret = btrfs_add_dead_root(dead_root, latest);
234 if (ret)
235 goto err;
236 goto again;
237next:
238 slot++;
239 path->slots[0]++;
240 }
241 ret = 0;
242err:
243 btrfs_free_path(path);
244 return ret;
245}
246
247/* drop the root item for 'key' from 'root' */
248int btrfs_del_root(struct btrfs_trans_handle *trans, struct btrfs_root *root,
249 struct btrfs_key *key)
250{
251 struct btrfs_path *path;
252 int ret;
253 u32 refs;
254 struct btrfs_root_item *ri;
255 struct extent_buffer *leaf;
256
257 path = btrfs_alloc_path();
258 BUG_ON(!path);
259 ret = btrfs_search_slot(trans, root, key, path, -1, 1);
260 if (ret < 0)
261 goto out;
262
263 BUG_ON(ret != 0);
264 leaf = path->nodes[0];
265 ri = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_item);
266
267 refs = btrfs_disk_root_refs(leaf, ri);
268 BUG_ON(refs != 0);
269 ret = btrfs_del_item(trans, root, path);
270out:
271 btrfs_release_path(root, path);
272 btrfs_free_path(path);
273 return ret;
274}
275
276#if 0 /* this will get used when snapshot deletion is implemented */
277int btrfs_del_root_ref(struct btrfs_trans_handle *trans,
278 struct btrfs_root *tree_root,
279 u64 root_id, u8 type, u64 ref_id)
280{
281 struct btrfs_key key;
282 int ret;
283 struct btrfs_path *path;
284
285 path = btrfs_alloc_path();
286
287 key.objectid = root_id;
288 key.type = type;
289 key.offset = ref_id;
290
291 ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
292 BUG_ON(ret);
293
294 ret = btrfs_del_item(trans, tree_root, path);
295 BUG_ON(ret);
296
297 btrfs_free_path(path);
298 return ret;
299}
300#endif
301
302int btrfs_find_root_ref(struct btrfs_root *tree_root,
303 struct btrfs_path *path,
304 u64 root_id, u64 ref_id)
305{
306 struct btrfs_key key;
307 int ret;
308
309 key.objectid = root_id;
310 key.type = BTRFS_ROOT_REF_KEY;
311 key.offset = ref_id;
312
313 ret = btrfs_search_slot(NULL, tree_root, &key, path, 0, 0);
314 return ret;
315}
316
317
318/*
319 * add a btrfs_root_ref item. type is either BTRFS_ROOT_REF_KEY
320 * or BTRFS_ROOT_BACKREF_KEY.
321 *
322 * The dirid, sequence, name and name_len refer to the directory entry
323 * that is referencing the root.
324 *
325 * For a forward ref, the root_id is the id of the tree referencing
326 * the root and ref_id is the id of the subvol or snapshot.
327 *
328 * For a back ref the root_id is the id of the subvol or snapshot and
329 * ref_id is the id of the tree referencing it.
330 */
331int btrfs_add_root_ref(struct btrfs_trans_handle *trans,
332 struct btrfs_root *tree_root,
333 u64 root_id, u8 type, u64 ref_id,
334 u64 dirid, u64 sequence,
335 const char *name, int name_len)
336{
337 struct btrfs_key key;
338 int ret;
339 struct btrfs_path *path;
340 struct btrfs_root_ref *ref;
341 struct extent_buffer *leaf;
342 unsigned long ptr;
343
344
345 path = btrfs_alloc_path();
346
347 key.objectid = root_id;
348 key.type = type;
349 key.offset = ref_id;
350
351 ret = btrfs_insert_empty_item(trans, tree_root, path, &key,
352 sizeof(*ref) + name_len);
353 BUG_ON(ret);
354
355 leaf = path->nodes[0];
356 ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
357 btrfs_set_root_ref_dirid(leaf, ref, dirid);
358 btrfs_set_root_ref_sequence(leaf, ref, sequence);
359 btrfs_set_root_ref_name_len(leaf, ref, name_len);
360 ptr = (unsigned long)(ref + 1);
361 write_extent_buffer(leaf, name, ptr, name_len);
362 btrfs_mark_buffer_dirty(leaf);
363
364 btrfs_free_path(path);
365 return ret;
366}
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