1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * linux/fs/hfs/bnode.c 4 * 5 * Copyright (C) 2001 6 * Brad Boyer (flar@allandria.com) 7 * (C) 2003 Ardis Technologies <roman@ardistech.com> 8 * 9 * Handle basic btree node operations 10 */ 11 12 #include <linux/pagemap.h> 13 #include <linux/slab.h> 14 #include <linux/swap.h> 15 16 #include "btree.h" 17 18 void hfs_bnode_read(struct hfs_bnode *node, void *buf, int off, int len) 19 { 20 struct page *page; 21 int pagenum; 22 int bytes_read; 23 int bytes_to_read; 24 void *vaddr; 25 26 off += node->page_offset; 27 pagenum = off >> PAGE_SHIFT; 28 off &= ~PAGE_MASK; /* compute page offset for the first page */ 29 30 for (bytes_read = 0; bytes_read < len; bytes_read += bytes_to_read) { 31 if (pagenum >= node->tree->pages_per_bnode) 32 break; 33 page = node->page[pagenum]; 34 bytes_to_read = min_t(int, len - bytes_read, PAGE_SIZE - off); 35 36 vaddr = kmap_atomic(page); 37 memcpy(buf + bytes_read, vaddr + off, bytes_to_read); 38 kunmap_atomic(vaddr); 39 40 pagenum++; 41 off = 0; /* page offset only applies to the first page */ 42 } 43 } 44 45 u16 hfs_bnode_read_u16(struct hfs_bnode *node, int off) 46 { 47 __be16 data; 48 // optimize later... 49 hfs_bnode_read(node, &data, off, 2); 50 return be16_to_cpu(data); 51 } 52 53 u8 hfs_bnode_read_u8(struct hfs_bnode *node, int off) 54 { 55 u8 data; 56 // optimize later... 57 hfs_bnode_read(node, &data, off, 1); 58 return data; 59 } 60 61 void hfs_bnode_read_key(struct hfs_bnode *node, void *key, int off) 62 { 63 struct hfs_btree *tree; 64 int key_len; 65 66 tree = node->tree; 67 if (node->type == HFS_NODE_LEAF || 68 tree->attributes & HFS_TREE_VARIDXKEYS) 69 key_len = hfs_bnode_read_u8(node, off) + 1; 70 else 71 key_len = tree->max_key_len + 1; 72 73 hfs_bnode_read(node, key, off, key_len); 74 } 75 76 void hfs_bnode_write(struct hfs_bnode *node, void *buf, int off, int len) 77 { 78 struct page *page; 79 80 off += node->page_offset; 81 page = node->page[0]; 82 83 memcpy(kmap(page) + off, buf, len); 84 kunmap(page); 85 set_page_dirty(page); 86 } 87 88 void hfs_bnode_write_u16(struct hfs_bnode *node, int off, u16 data) 89 { 90 __be16 v = cpu_to_be16(data); 91 // optimize later... 92 hfs_bnode_write(node, &v, off, 2); 93 } 94 95 void hfs_bnode_write_u8(struct hfs_bnode *node, int off, u8 data) 96 { 97 // optimize later... 98 hfs_bnode_write(node, &data, off, 1); 99 } 100 101 void hfs_bnode_clear(struct hfs_bnode *node, int off, int len) 102 { 103 struct page *page; 104 105 off += node->page_offset; 106 page = node->page[0]; 107 108 memset(kmap(page) + off, 0, len); 109 kunmap(page); 110 set_page_dirty(page); 111 } 112 113 void hfs_bnode_copy(struct hfs_bnode *dst_node, int dst, 114 struct hfs_bnode *src_node, int src, int len) 115 { 116 struct page *src_page, *dst_page; 117 118 hfs_dbg(BNODE_MOD, "copybytes: %u,%u,%u\n", dst, src, len); 119 if (!len) 120 return; 121 src += src_node->page_offset; 122 dst += dst_node->page_offset; 123 src_page = src_node->page[0]; 124 dst_page = dst_node->page[0]; 125 126 memcpy(kmap(dst_page) + dst, kmap(src_page) + src, len); 127 kunmap(src_page); 128 kunmap(dst_page); 129 set_page_dirty(dst_page); 130 } 131 132 void hfs_bnode_move(struct hfs_bnode *node, int dst, int src, int len) 133 { 134 struct page *page; 135 void *ptr; 136 137 hfs_dbg(BNODE_MOD, "movebytes: %u,%u,%u\n", dst, src, len); 138 if (!len) 139 return; 140 src += node->page_offset; 141 dst += node->page_offset; 142 page = node->page[0]; 143 ptr = kmap(page); 144 memmove(ptr + dst, ptr + src, len); 145 kunmap(page); 146 set_page_dirty(page); 147 } 148 149 void hfs_bnode_dump(struct hfs_bnode *node) 150 { 151 struct hfs_bnode_desc desc; 152 __be32 cnid; 153 int i, off, key_off; 154 155 hfs_dbg(BNODE_MOD, "bnode: %d\n", node->this); 156 hfs_bnode_read(node, &desc, 0, sizeof(desc)); 157 hfs_dbg(BNODE_MOD, "%d, %d, %d, %d, %d\n", 158 be32_to_cpu(desc.next), be32_to_cpu(desc.prev), 159 desc.type, desc.height, be16_to_cpu(desc.num_recs)); 160 161 off = node->tree->node_size - 2; 162 for (i = be16_to_cpu(desc.num_recs); i >= 0; off -= 2, i--) { 163 key_off = hfs_bnode_read_u16(node, off); 164 hfs_dbg_cont(BNODE_MOD, " %d", key_off); 165 if (i && node->type == HFS_NODE_INDEX) { 166 int tmp; 167 168 if (node->tree->attributes & HFS_TREE_VARIDXKEYS) 169 tmp = (hfs_bnode_read_u8(node, key_off) | 1) + 1; 170 else 171 tmp = node->tree->max_key_len + 1; 172 hfs_dbg_cont(BNODE_MOD, " (%d,%d", 173 tmp, hfs_bnode_read_u8(node, key_off)); 174 hfs_bnode_read(node, &cnid, key_off + tmp, 4); 175 hfs_dbg_cont(BNODE_MOD, ",%d)", be32_to_cpu(cnid)); 176 } else if (i && node->type == HFS_NODE_LEAF) { 177 int tmp; 178 179 tmp = hfs_bnode_read_u8(node, key_off); 180 hfs_dbg_cont(BNODE_MOD, " (%d)", tmp); 181 } 182 } 183 hfs_dbg_cont(BNODE_MOD, "\n"); 184 } 185 186 void hfs_bnode_unlink(struct hfs_bnode *node) 187 { 188 struct hfs_btree *tree; 189 struct hfs_bnode *tmp; 190 __be32 cnid; 191 192 tree = node->tree; 193 if (node->prev) { 194 tmp = hfs_bnode_find(tree, node->prev); 195 if (IS_ERR(tmp)) 196 return; 197 tmp->next = node->next; 198 cnid = cpu_to_be32(tmp->next); 199 hfs_bnode_write(tmp, &cnid, offsetof(struct hfs_bnode_desc, next), 4); 200 hfs_bnode_put(tmp); 201 } else if (node->type == HFS_NODE_LEAF) 202 tree->leaf_head = node->next; 203 204 if (node->next) { 205 tmp = hfs_bnode_find(tree, node->next); 206 if (IS_ERR(tmp)) 207 return; 208 tmp->prev = node->prev; 209 cnid = cpu_to_be32(tmp->prev); 210 hfs_bnode_write(tmp, &cnid, offsetof(struct hfs_bnode_desc, prev), 4); 211 hfs_bnode_put(tmp); 212 } else if (node->type == HFS_NODE_LEAF) 213 tree->leaf_tail = node->prev; 214 215 // move down? 216 if (!node->prev && !node->next) { 217 printk(KERN_DEBUG "hfs_btree_del_level\n"); 218 } 219 if (!node->parent) { 220 tree->root = 0; 221 tree->depth = 0; 222 } 223 set_bit(HFS_BNODE_DELETED, &node->flags); 224 } 225 226 static inline int hfs_bnode_hash(u32 num) 227 { 228 num = (num >> 16) + num; 229 num += num >> 8; 230 return num & (NODE_HASH_SIZE - 1); 231 } 232 233 struct hfs_bnode *hfs_bnode_findhash(struct hfs_btree *tree, u32 cnid) 234 { 235 struct hfs_bnode *node; 236 237 if (cnid >= tree->node_count) { 238 pr_err("request for non-existent node %d in B*Tree\n", cnid); 239 return NULL; 240 } 241 242 for (node = tree->node_hash[hfs_bnode_hash(cnid)]; 243 node; node = node->next_hash) { 244 if (node->this == cnid) { 245 return node; 246 } 247 } 248 return NULL; 249 } 250 251 static struct hfs_bnode *__hfs_bnode_create(struct hfs_btree *tree, u32 cnid) 252 { 253 struct hfs_bnode *node, *node2; 254 struct address_space *mapping; 255 struct page *page; 256 int size, block, i, hash; 257 loff_t off; 258 259 if (cnid >= tree->node_count) { 260 pr_err("request for non-existent node %d in B*Tree\n", cnid); 261 return NULL; 262 } 263 264 size = sizeof(struct hfs_bnode) + tree->pages_per_bnode * 265 sizeof(struct page *); 266 node = kzalloc(size, GFP_KERNEL); 267 if (!node) 268 return NULL; 269 node->tree = tree; 270 node->this = cnid; 271 set_bit(HFS_BNODE_NEW, &node->flags); 272 atomic_set(&node->refcnt, 1); 273 hfs_dbg(BNODE_REFS, "new_node(%d:%d): 1\n", 274 node->tree->cnid, node->this); 275 init_waitqueue_head(&node->lock_wq); 276 spin_lock(&tree->hash_lock); 277 node2 = hfs_bnode_findhash(tree, cnid); 278 if (!node2) { 279 hash = hfs_bnode_hash(cnid); 280 node->next_hash = tree->node_hash[hash]; 281 tree->node_hash[hash] = node; 282 tree->node_hash_cnt++; 283 } else { 284 spin_unlock(&tree->hash_lock); 285 kfree(node); 286 wait_event(node2->lock_wq, !test_bit(HFS_BNODE_NEW, &node2->flags)); 287 return node2; 288 } 289 spin_unlock(&tree->hash_lock); 290 291 mapping = tree->inode->i_mapping; 292 off = (loff_t)cnid * tree->node_size; 293 block = off >> PAGE_SHIFT; 294 node->page_offset = off & ~PAGE_MASK; 295 for (i = 0; i < tree->pages_per_bnode; i++) { 296 page = read_mapping_page(mapping, block++, NULL); 297 if (IS_ERR(page)) 298 goto fail; 299 node->page[i] = page; 300 } 301 302 return node; 303 fail: 304 set_bit(HFS_BNODE_ERROR, &node->flags); 305 return node; 306 } 307 308 void hfs_bnode_unhash(struct hfs_bnode *node) 309 { 310 struct hfs_bnode **p; 311 312 hfs_dbg(BNODE_REFS, "remove_node(%d:%d): %d\n", 313 node->tree->cnid, node->this, atomic_read(&node->refcnt)); 314 for (p = &node->tree->node_hash[hfs_bnode_hash(node->this)]; 315 *p && *p != node; p = &(*p)->next_hash) 316 ; 317 BUG_ON(!*p); 318 *p = node->next_hash; 319 node->tree->node_hash_cnt--; 320 } 321 322 /* Load a particular node out of a tree */ 323 struct hfs_bnode *hfs_bnode_find(struct hfs_btree *tree, u32 num) 324 { 325 struct hfs_bnode *node; 326 struct hfs_bnode_desc *desc; 327 int i, rec_off, off, next_off; 328 int entry_size, key_size; 329 330 spin_lock(&tree->hash_lock); 331 node = hfs_bnode_findhash(tree, num); 332 if (node) { 333 hfs_bnode_get(node); 334 spin_unlock(&tree->hash_lock); 335 wait_event(node->lock_wq, !test_bit(HFS_BNODE_NEW, &node->flags)); 336 if (test_bit(HFS_BNODE_ERROR, &node->flags)) 337 goto node_error; 338 return node; 339 } 340 spin_unlock(&tree->hash_lock); 341 node = __hfs_bnode_create(tree, num); 342 if (!node) 343 return ERR_PTR(-ENOMEM); 344 if (test_bit(HFS_BNODE_ERROR, &node->flags)) 345 goto node_error; 346 if (!test_bit(HFS_BNODE_NEW, &node->flags)) 347 return node; 348 349 desc = (struct hfs_bnode_desc *)(kmap(node->page[0]) + node->page_offset); 350 node->prev = be32_to_cpu(desc->prev); 351 node->next = be32_to_cpu(desc->next); 352 node->num_recs = be16_to_cpu(desc->num_recs); 353 node->type = desc->type; 354 node->height = desc->height; 355 kunmap(node->page[0]); 356 357 switch (node->type) { 358 case HFS_NODE_HEADER: 359 case HFS_NODE_MAP: 360 if (node->height != 0) 361 goto node_error; 362 break; 363 case HFS_NODE_LEAF: 364 if (node->height != 1) 365 goto node_error; 366 break; 367 case HFS_NODE_INDEX: 368 if (node->height <= 1 || node->height > tree->depth) 369 goto node_error; 370 break; 371 default: 372 goto node_error; 373 } 374 375 rec_off = tree->node_size - 2; 376 off = hfs_bnode_read_u16(node, rec_off); 377 if (off != sizeof(struct hfs_bnode_desc)) 378 goto node_error; 379 for (i = 1; i <= node->num_recs; off = next_off, i++) { 380 rec_off -= 2; 381 next_off = hfs_bnode_read_u16(node, rec_off); 382 if (next_off <= off || 383 next_off > tree->node_size || 384 next_off & 1) 385 goto node_error; 386 entry_size = next_off - off; 387 if (node->type != HFS_NODE_INDEX && 388 node->type != HFS_NODE_LEAF) 389 continue; 390 key_size = hfs_bnode_read_u8(node, off) + 1; 391 if (key_size >= entry_size /*|| key_size & 1*/) 392 goto node_error; 393 } 394 clear_bit(HFS_BNODE_NEW, &node->flags); 395 wake_up(&node->lock_wq); 396 return node; 397 398 node_error: 399 set_bit(HFS_BNODE_ERROR, &node->flags); 400 clear_bit(HFS_BNODE_NEW, &node->flags); 401 wake_up(&node->lock_wq); 402 hfs_bnode_put(node); 403 return ERR_PTR(-EIO); 404 } 405 406 void hfs_bnode_free(struct hfs_bnode *node) 407 { 408 int i; 409 410 for (i = 0; i < node->tree->pages_per_bnode; i++) 411 if (node->page[i]) 412 put_page(node->page[i]); 413 kfree(node); 414 } 415 416 struct hfs_bnode *hfs_bnode_create(struct hfs_btree *tree, u32 num) 417 { 418 struct hfs_bnode *node; 419 struct page **pagep; 420 int i; 421 422 spin_lock(&tree->hash_lock); 423 node = hfs_bnode_findhash(tree, num); 424 spin_unlock(&tree->hash_lock); 425 if (node) { 426 pr_crit("new node %u already hashed?\n", num); 427 WARN_ON(1); 428 return node; 429 } 430 node = __hfs_bnode_create(tree, num); 431 if (!node) 432 return ERR_PTR(-ENOMEM); 433 if (test_bit(HFS_BNODE_ERROR, &node->flags)) { 434 hfs_bnode_put(node); 435 return ERR_PTR(-EIO); 436 } 437 438 pagep = node->page; 439 memset(kmap(*pagep) + node->page_offset, 0, 440 min((int)PAGE_SIZE, (int)tree->node_size)); 441 set_page_dirty(*pagep); 442 kunmap(*pagep); 443 for (i = 1; i < tree->pages_per_bnode; i++) { 444 memset(kmap(*++pagep), 0, PAGE_SIZE); 445 set_page_dirty(*pagep); 446 kunmap(*pagep); 447 } 448 clear_bit(HFS_BNODE_NEW, &node->flags); 449 wake_up(&node->lock_wq); 450 451 return node; 452 } 453 454 void hfs_bnode_get(struct hfs_bnode *node) 455 { 456 if (node) { 457 atomic_inc(&node->refcnt); 458 hfs_dbg(BNODE_REFS, "get_node(%d:%d): %d\n", 459 node->tree->cnid, node->this, 460 atomic_read(&node->refcnt)); 461 } 462 } 463 464 /* Dispose of resources used by a node */ 465 void hfs_bnode_put(struct hfs_bnode *node) 466 { 467 if (node) { 468 struct hfs_btree *tree = node->tree; 469 int i; 470 471 hfs_dbg(BNODE_REFS, "put_node(%d:%d): %d\n", 472 node->tree->cnid, node->this, 473 atomic_read(&node->refcnt)); 474 BUG_ON(!atomic_read(&node->refcnt)); 475 if (!atomic_dec_and_lock(&node->refcnt, &tree->hash_lock)) 476 return; 477 for (i = 0; i < tree->pages_per_bnode; i++) { 478 if (!node->page[i]) 479 continue; 480 mark_page_accessed(node->page[i]); 481 } 482 483 if (test_bit(HFS_BNODE_DELETED, &node->flags)) { 484 hfs_bnode_unhash(node); 485 spin_unlock(&tree->hash_lock); 486 hfs_bmap_free(node); 487 hfs_bnode_free(node); 488 return; 489 } 490 spin_unlock(&tree->hash_lock); 491 } 492 } 493