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 */ 30 int 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); 44 again: 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 66 out: 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 */ 76 int 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; 109 out: 110 btrfs_free_path(path); 111 return ret; 112 } 113 114 int btrfs_set_root_node(struct btrfs_root_item *item, 115 struct extent_buffer *node) 116 { 117 btrfs_set_root_bytenr(item, node->start); 118 btrfs_set_root_level(item, btrfs_header_level(node)); 119 btrfs_set_root_generation(item, btrfs_header_generation(node)); 120 return 0; 121 } 122 123 /* 124 * copy the data in 'item' into the btree 125 */ 126 int btrfs_update_root(struct btrfs_trans_handle *trans, struct btrfs_root 127 *root, struct btrfs_key *key, struct btrfs_root_item 128 *item) 129 { 130 struct btrfs_path *path; 131 struct extent_buffer *l; 132 int ret; 133 int slot; 134 unsigned long ptr; 135 136 path = btrfs_alloc_path(); 137 BUG_ON(!path); 138 ret = btrfs_search_slot(trans, root, key, path, 0, 1); 139 if (ret < 0) 140 goto out; 141 142 if (ret != 0) { 143 btrfs_print_leaf(root, path->nodes[0]); 144 printk(KERN_CRIT "unable to update root key %llu %u %llu\n", 145 (unsigned long long)key->objectid, key->type, 146 (unsigned long long)key->offset); 147 BUG_ON(1); 148 } 149 150 l = path->nodes[0]; 151 slot = path->slots[0]; 152 ptr = btrfs_item_ptr_offset(l, slot); 153 write_extent_buffer(l, item, ptr, sizeof(*item)); 154 btrfs_mark_buffer_dirty(path->nodes[0]); 155 out: 156 btrfs_release_path(root, path); 157 btrfs_free_path(path); 158 return ret; 159 } 160 161 int btrfs_insert_root(struct btrfs_trans_handle *trans, struct btrfs_root 162 *root, struct btrfs_key *key, struct btrfs_root_item 163 *item) 164 { 165 int ret; 166 ret = btrfs_insert_item(trans, root, key, item, sizeof(*item)); 167 return ret; 168 } 169 170 /* 171 * at mount time we want to find all the old transaction snapshots that were in 172 * the process of being deleted if we crashed. This is any root item with an 173 * offset lower than the latest root. They need to be queued for deletion to 174 * finish what was happening when we crashed. 175 */ 176 int btrfs_find_dead_roots(struct btrfs_root *root, u64 objectid) 177 { 178 struct btrfs_root *dead_root; 179 struct btrfs_item *item; 180 struct btrfs_root_item *ri; 181 struct btrfs_key key; 182 struct btrfs_key found_key; 183 struct btrfs_path *path; 184 int ret; 185 u32 nritems; 186 struct extent_buffer *leaf; 187 int slot; 188 189 key.objectid = objectid; 190 btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY); 191 key.offset = 0; 192 path = btrfs_alloc_path(); 193 if (!path) 194 return -ENOMEM; 195 196 again: 197 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); 198 if (ret < 0) 199 goto err; 200 while (1) { 201 leaf = path->nodes[0]; 202 nritems = btrfs_header_nritems(leaf); 203 slot = path->slots[0]; 204 if (slot >= nritems) { 205 ret = btrfs_next_leaf(root, path); 206 if (ret) 207 break; 208 leaf = path->nodes[0]; 209 nritems = btrfs_header_nritems(leaf); 210 slot = path->slots[0]; 211 } 212 item = btrfs_item_nr(leaf, slot); 213 btrfs_item_key_to_cpu(leaf, &key, slot); 214 if (btrfs_key_type(&key) != BTRFS_ROOT_ITEM_KEY) 215 goto next; 216 217 if (key.objectid < objectid) 218 goto next; 219 220 if (key.objectid > objectid) 221 break; 222 223 ri = btrfs_item_ptr(leaf, slot, struct btrfs_root_item); 224 if (btrfs_disk_root_refs(leaf, ri) != 0) 225 goto next; 226 227 memcpy(&found_key, &key, sizeof(key)); 228 key.offset++; 229 btrfs_release_path(root, path); 230 dead_root = 231 btrfs_read_fs_root_no_radix(root->fs_info->tree_root, 232 &found_key); 233 if (IS_ERR(dead_root)) { 234 ret = PTR_ERR(dead_root); 235 goto err; 236 } 237 238 ret = btrfs_add_dead_root(dead_root); 239 if (ret) 240 goto err; 241 goto again; 242 next: 243 slot++; 244 path->slots[0]++; 245 } 246 ret = 0; 247 err: 248 btrfs_free_path(path); 249 return ret; 250 } 251 252 /* drop the root item for 'key' from 'root' */ 253 int btrfs_del_root(struct btrfs_trans_handle *trans, struct btrfs_root *root, 254 struct btrfs_key *key) 255 { 256 struct btrfs_path *path; 257 int ret; 258 u32 refs; 259 struct btrfs_root_item *ri; 260 struct extent_buffer *leaf; 261 262 path = btrfs_alloc_path(); 263 BUG_ON(!path); 264 ret = btrfs_search_slot(trans, root, key, path, -1, 1); 265 if (ret < 0) 266 goto out; 267 268 BUG_ON(ret != 0); 269 leaf = path->nodes[0]; 270 ri = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_item); 271 272 refs = btrfs_disk_root_refs(leaf, ri); 273 BUG_ON(refs != 0); 274 ret = btrfs_del_item(trans, root, path); 275 out: 276 btrfs_release_path(root, path); 277 btrfs_free_path(path); 278 return ret; 279 } 280 281 #if 0 /* this will get used when snapshot deletion is implemented */ 282 int btrfs_del_root_ref(struct btrfs_trans_handle *trans, 283 struct btrfs_root *tree_root, 284 u64 root_id, u8 type, u64 ref_id) 285 { 286 struct btrfs_key key; 287 int ret; 288 struct btrfs_path *path; 289 290 path = btrfs_alloc_path(); 291 292 key.objectid = root_id; 293 key.type = type; 294 key.offset = ref_id; 295 296 ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1); 297 BUG_ON(ret); 298 299 ret = btrfs_del_item(trans, tree_root, path); 300 BUG_ON(ret); 301 302 btrfs_free_path(path); 303 return ret; 304 } 305 #endif 306 307 int btrfs_find_root_ref(struct btrfs_root *tree_root, 308 struct btrfs_path *path, 309 u64 root_id, u64 ref_id) 310 { 311 struct btrfs_key key; 312 int ret; 313 314 key.objectid = root_id; 315 key.type = BTRFS_ROOT_REF_KEY; 316 key.offset = ref_id; 317 318 ret = btrfs_search_slot(NULL, tree_root, &key, path, 0, 0); 319 return ret; 320 } 321 322 323 /* 324 * add a btrfs_root_ref item. type is either BTRFS_ROOT_REF_KEY 325 * or BTRFS_ROOT_BACKREF_KEY. 326 * 327 * The dirid, sequence, name and name_len refer to the directory entry 328 * that is referencing the root. 329 * 330 * For a forward ref, the root_id is the id of the tree referencing 331 * the root and ref_id is the id of the subvol or snapshot. 332 * 333 * For a back ref the root_id is the id of the subvol or snapshot and 334 * ref_id is the id of the tree referencing it. 335 */ 336 int btrfs_add_root_ref(struct btrfs_trans_handle *trans, 337 struct btrfs_root *tree_root, 338 u64 root_id, u8 type, u64 ref_id, 339 u64 dirid, u64 sequence, 340 const char *name, int name_len) 341 { 342 struct btrfs_key key; 343 int ret; 344 struct btrfs_path *path; 345 struct btrfs_root_ref *ref; 346 struct extent_buffer *leaf; 347 unsigned long ptr; 348 349 350 path = btrfs_alloc_path(); 351 352 key.objectid = root_id; 353 key.type = type; 354 key.offset = ref_id; 355 356 ret = btrfs_insert_empty_item(trans, tree_root, path, &key, 357 sizeof(*ref) + name_len); 358 BUG_ON(ret); 359 360 leaf = path->nodes[0]; 361 ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref); 362 btrfs_set_root_ref_dirid(leaf, ref, dirid); 363 btrfs_set_root_ref_sequence(leaf, ref, sequence); 364 btrfs_set_root_ref_name_len(leaf, ref, name_len); 365 ptr = (unsigned long)(ref + 1); 366 write_extent_buffer(leaf, name, ptr, name_len); 367 btrfs_mark_buffer_dirty(leaf); 368 369 btrfs_free_path(path); 370 return ret; 371 } 372