fs/hfs/bnode.c

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