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         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 hfs_btree *tree;
 117         struct page *src_page, *dst_page;
 118
 119         hfs_dbg(BNODE_MOD, "copybytes: %u,%u,%u\n", dst, src, len);
 120         if (!len)
 121                 return;
 122         tree = src_node->tree;
 123         src += src_node->page_offset;
 124         dst += dst_node->page_offset;
 125         src_page = src_node->page[0];
 126         dst_page = dst_node->page[0];
 127
 128         memcpy(kmap(dst_page) + dst, kmap(src_page) + src, len);
 129         kunmap(src_page);
 130         kunmap(dst_page);
 131         set_page_dirty(dst_page);
 132 }
 133
 134 void hfs_bnode_move(struct hfs_bnode *node, int dst, int src, int len)
 135 {
 136         struct page *page;
 137         void *ptr;
 138
 139         hfs_dbg(BNODE_MOD, "movebytes: %u,%u,%u\n", dst, src, len);
 140         if (!len)
 141                 return;
 142         src += node->page_offset;
 143         dst += node->page_offset;
 144         page = node->page[0];
 145         ptr = kmap(page);
 146         memmove(ptr + dst, ptr + src, len);
 147         kunmap(page);
 148         set_page_dirty(page);
 149 }
 150
 151 void hfs_bnode_dump(struct hfs_bnode *node)
 152 {
 153         struct hfs_bnode_desc desc;
 154         __be32 cnid;
 155         int i, off, key_off;
 156
 157         hfs_dbg(BNODE_MOD, "bnode: %d\n", node->this);
 158         hfs_bnode_read(node, &desc, 0, sizeof(desc));
 159         hfs_dbg(BNODE_MOD, "%d, %d, %d, %d, %d\n",
 160                 be32_to_cpu(desc.next), be32_to_cpu(desc.prev),
 161                 desc.type, desc.height, be16_to_cpu(desc.num_recs));
 162
 163         off = node->tree->node_size - 2;
 164         for (i = be16_to_cpu(desc.num_recs); i >= 0; off -= 2, i--) {
 165                 key_off = hfs_bnode_read_u16(node, off);
 166                 hfs_dbg_cont(BNODE_MOD, " %d", key_off);
 167                 if (i && node->type == HFS_NODE_INDEX) {
 168                         int tmp;
 169
 170                         if (node->tree->attributes & HFS_TREE_VARIDXKEYS)
 171                                 tmp = (hfs_bnode_read_u8(node, key_off) | 1) + 1;
 172                         else
 173                                 tmp = node->tree->max_key_len + 1;
 174                         hfs_dbg_cont(BNODE_MOD, " (%d,%d",
 175                                      tmp, hfs_bnode_read_u8(node, key_off));
 176                         hfs_bnode_read(node, &cnid, key_off + tmp, 4);
 177                         hfs_dbg_cont(BNODE_MOD, ",%d)", be32_to_cpu(cnid));
 178                 } else if (i && node->type == HFS_NODE_LEAF) {
 179                         int tmp;
 180
 181                         tmp = hfs_bnode_read_u8(node, key_off);
 182                         hfs_dbg_cont(BNODE_MOD, " (%d)", tmp);
 183                 }
 184         }
 185         hfs_dbg_cont(BNODE_MOD, "\n");
 186 }
 187
 188 void hfs_bnode_unlink(struct hfs_bnode *node)
 189 {
 190         struct hfs_btree *tree;
 191         struct hfs_bnode *tmp;
 192         __be32 cnid;
 193
 194         tree = node->tree;
 195         if (node->prev) {
 196                 tmp = hfs_bnode_find(tree, node->prev);
 197                 if (IS_ERR(tmp))
 198                         return;
 199                 tmp->next = node->next;
 200                 cnid = cpu_to_be32(tmp->next);
 201                 hfs_bnode_write(tmp, &cnid, offsetof(struct hfs_bnode_desc, next), 4);
 202                 hfs_bnode_put(tmp);
 203         } else if (node->type == HFS_NODE_LEAF)
 204                 tree->leaf_head = node->next;
 205
 206         if (node->next) {
 207                 tmp = hfs_bnode_find(tree, node->next);
 208                 if (IS_ERR(tmp))
 209                         return;
 210                 tmp->prev = node->prev;
 211                 cnid = cpu_to_be32(tmp->prev);
 212                 hfs_bnode_write(tmp, &cnid, offsetof(struct hfs_bnode_desc, prev), 4);
 213                 hfs_bnode_put(tmp);
 214         } else if (node->type == HFS_NODE_LEAF)
 215                 tree->leaf_tail = node->prev;
 216
 217         // move down?
 218         if (!node->prev && !node->next) {
 219                 printk(KERN_DEBUG "hfs_btree_del_level\n");
 220         }
 221         if (!node->parent) {
 222                 tree->root = 0;
 223                 tree->depth = 0;
 224         }
 225         set_bit(HFS_BNODE_DELETED, &node->flags);
 226 }
 227
 228 static inline int hfs_bnode_hash(u32 num)
 229 {
 230         num = (num >> 16) + num;
 231         num += num >> 8;
 232         return num & (NODE_HASH_SIZE - 1);
 233 }
 234
 235 struct hfs_bnode *hfs_bnode_findhash(struct hfs_btree *tree, u32 cnid)
 236 {
 237         struct hfs_bnode *node;
 238
 239         if (cnid >= tree->node_count) {
 240                 pr_err("request for non-existent node %d in B*Tree\n", cnid);
 241                 return NULL;
 242         }
 243
 244         for (node = tree->node_hash[hfs_bnode_hash(cnid)];
 245              node; node = node->next_hash) {
 246                 if (node->this == cnid) {
 247                         return node;
 248                 }
 249         }
 250         return NULL;
 251 }
 252
 253 static struct hfs_bnode *__hfs_bnode_create(struct hfs_btree *tree, u32 cnid)
 254 {
 255         struct super_block *sb;
 256         struct hfs_bnode *node, *node2;
 257         struct address_space *mapping;
 258         struct page *page;
 259         int size, block, i, hash;
 260         loff_t off;
 261
 262         if (cnid >= tree->node_count) {
 263                 pr_err("request for non-existent node %d in B*Tree\n", cnid);
 264                 return NULL;
 265         }
 266
 267         sb = tree->inode->i_sb;
 268         size = sizeof(struct hfs_bnode) + tree->pages_per_bnode *
 269                 sizeof(struct page *);
 270         node = kzalloc(size, GFP_KERNEL);
 271         if (!node)
 272                 return NULL;
 273         node->tree = tree;
 274         node->this = cnid;
 275         set_bit(HFS_BNODE_NEW, &node->flags);
 276         atomic_set(&node->refcnt, 1);
 277         hfs_dbg(BNODE_REFS, "new_node(%d:%d): 1\n",
 278                 node->tree->cnid, node->this);
 279         init_waitqueue_head(&node->lock_wq);
 280         spin_lock(&tree->hash_lock);
 281         node2 = hfs_bnode_findhash(tree, cnid);
 282         if (!node2) {
 283                 hash = hfs_bnode_hash(cnid);
 284                 node->next_hash = tree->node_hash[hash];
 285                 tree->node_hash[hash] = node;
 286                 tree->node_hash_cnt++;
 287         } else {
 288                 spin_unlock(&tree->hash_lock);
 289                 kfree(node);
 290                 wait_event(node2->lock_wq, !test_bit(HFS_BNODE_NEW, &node2->flags));
 291                 return node2;
 292         }
 293         spin_unlock(&tree->hash_lock);
 294
 295         mapping = tree->inode->i_mapping;
 296         off = (loff_t)cnid * tree->node_size;
 297         block = off >> PAGE_SHIFT;
 298         node->page_offset = off & ~PAGE_MASK;
 299         for (i = 0; i < tree->pages_per_bnode; i++) {
 300                 page = read_mapping_page(mapping, block++, NULL);
 301                 if (IS_ERR(page))
 302                         goto fail;
 303                 if (PageError(page)) {
 304                         put_page(page);
 305                         goto fail;
 306                 }
 307                 node->page[i] = page;
 308         }
 309
 310         return node;
 311 fail:
 312         set_bit(HFS_BNODE_ERROR, &node->flags);
 313         return node;
 314 }
 315
 316 void hfs_bnode_unhash(struct hfs_bnode *node)
 317 {
 318         struct hfs_bnode **p;
 319
 320         hfs_dbg(BNODE_REFS, "remove_node(%d:%d): %d\n",
 321                 node->tree->cnid, node->this, atomic_read(&node->refcnt));
 322         for (p = &node->tree->node_hash[hfs_bnode_hash(node->this)];
 323              *p && *p != node; p = &(*p)->next_hash)
 324                 ;
 325         BUG_ON(!*p);
 326         *p = node->next_hash;
 327         node->tree->node_hash_cnt--;
 328 }
 329
 330 /* Load a particular node out of a tree */
 331 struct hfs_bnode *hfs_bnode_find(struct hfs_btree *tree, u32 num)
 332 {
 333         struct hfs_bnode *node;
 334         struct hfs_bnode_desc *desc;
 335         int i, rec_off, off, next_off;
 336         int entry_size, key_size;
 337
 338         spin_lock(&tree->hash_lock);
 339         node = hfs_bnode_findhash(tree, num);
 340         if (node) {
 341                 hfs_bnode_get(node);
 342                 spin_unlock(&tree->hash_lock);
 343                 wait_event(node->lock_wq, !test_bit(HFS_BNODE_NEW, &node->flags));
 344                 if (test_bit(HFS_BNODE_ERROR, &node->flags))
 345                         goto node_error;
 346                 return node;
 347         }
 348         spin_unlock(&tree->hash_lock);
 349         node = __hfs_bnode_create(tree, num);
 350         if (!node)
 351                 return ERR_PTR(-ENOMEM);
 352         if (test_bit(HFS_BNODE_ERROR, &node->flags))
 353                 goto node_error;
 354         if (!test_bit(HFS_BNODE_NEW, &node->flags))
 355                 return node;
 356
 357         desc = (struct hfs_bnode_desc *)(kmap(node->page[0]) + node->page_offset);
 358         node->prev = be32_to_cpu(desc->prev);
 359         node->next = be32_to_cpu(desc->next);
 360         node->num_recs = be16_to_cpu(desc->num_recs);
 361         node->type = desc->type;
 362         node->height = desc->height;
 363         kunmap(node->page[0]);
 364
 365         switch (node->type) {
 366         case HFS_NODE_HEADER:
 367         case HFS_NODE_MAP:
 368                 if (node->height != 0)
 369                         goto node_error;
 370                 break;
 371         case HFS_NODE_LEAF:
 372                 if (node->height != 1)
 373                         goto node_error;
 374                 break;
 375         case HFS_NODE_INDEX:
 376                 if (node->height <= 1 || node->height > tree->depth)
 377                         goto node_error;
 378                 break;
 379         default:
 380                 goto node_error;
 381         }
 382
 383         rec_off = tree->node_size - 2;
 384         off = hfs_bnode_read_u16(node, rec_off);
 385         if (off != sizeof(struct hfs_bnode_desc))
 386                 goto node_error;
 387         for (i = 1; i <= node->num_recs; off = next_off, i++) {
 388                 rec_off -= 2;
 389                 next_off = hfs_bnode_read_u16(node, rec_off);
 390                 if (next_off <= off ||
 391                     next_off > tree->node_size ||
 392                     next_off & 1)
 393                         goto node_error;
 394                 entry_size = next_off - off;
 395                 if (node->type != HFS_NODE_INDEX &&
 396                     node->type != HFS_NODE_LEAF)
 397                         continue;
 398                 key_size = hfs_bnode_read_u8(node, off) + 1;
 399                 if (key_size >= entry_size /*|| key_size & 1*/)
 400                         goto node_error;
 401         }
 402         clear_bit(HFS_BNODE_NEW, &node->flags);
 403         wake_up(&node->lock_wq);
 404         return node;
 405
 406 node_error:
 407         set_bit(HFS_BNODE_ERROR, &node->flags);
 408         clear_bit(HFS_BNODE_NEW, &node->flags);
 409         wake_up(&node->lock_wq);
 410         hfs_bnode_put(node);
 411         return ERR_PTR(-EIO);
 412 }
 413
 414 void hfs_bnode_free(struct hfs_bnode *node)
 415 {
 416         int i;
 417
 418         for (i = 0; i < node->tree->pages_per_bnode; i++)
 419                 if (node->page[i])
 420                         put_page(node->page[i]);
 421         kfree(node);
 422 }
 423
 424 struct hfs_bnode *hfs_bnode_create(struct hfs_btree *tree, u32 num)
 425 {
 426         struct hfs_bnode *node;
 427         struct page **pagep;
 428         int i;
 429
 430         spin_lock(&tree->hash_lock);
 431         node = hfs_bnode_findhash(tree, num);
 432         spin_unlock(&tree->hash_lock);
 433         if (node) {
 434                 pr_crit("new node %u already hashed?\n", num);
 435                 WARN_ON(1);
 436                 return node;
 437         }
 438         node = __hfs_bnode_create(tree, num);
 439         if (!node)
 440                 return ERR_PTR(-ENOMEM);
 441         if (test_bit(HFS_BNODE_ERROR, &node->flags)) {
 442                 hfs_bnode_put(node);
 443                 return ERR_PTR(-EIO);
 444         }
 445
 446         pagep = node->page;
 447         memset(kmap(*pagep) + node->page_offset, 0,
 448                min((int)PAGE_SIZE, (int)tree->node_size));
 449         set_page_dirty(*pagep);
 450         kunmap(*pagep);
 451         for (i = 1; i < tree->pages_per_bnode; i++) {
 452                 memset(kmap(*++pagep), 0, PAGE_SIZE);
 453                 set_page_dirty(*pagep);
 454                 kunmap(*pagep);
 455         }
 456         clear_bit(HFS_BNODE_NEW, &node->flags);
 457         wake_up(&node->lock_wq);
 458
 459         return node;
 460 }
 461
 462 void hfs_bnode_get(struct hfs_bnode *node)
 463 {
 464         if (node) {
 465                 atomic_inc(&node->refcnt);
 466                 hfs_dbg(BNODE_REFS, "get_node(%d:%d): %d\n",
 467                         node->tree->cnid, node->this,
 468                         atomic_read(&node->refcnt));
 469         }
 470 }
 471
 472 /* Dispose of resources used by a node */
 473 void hfs_bnode_put(struct hfs_bnode *node)
 474 {
 475         if (node) {
 476                 struct hfs_btree *tree = node->tree;
 477                 int i;
 478
 479                 hfs_dbg(BNODE_REFS, "put_node(%d:%d): %d\n",
 480                         node->tree->cnid, node->this,
 481                         atomic_read(&node->refcnt));
 482                 BUG_ON(!atomic_read(&node->refcnt));
 483                 if (!atomic_dec_and_lock(&node->refcnt, &tree->hash_lock))
 484                         return;
 485                 for (i = 0; i < tree->pages_per_bnode; i++) {
 486                         if (!node->page[i])
 487                                 continue;
 488                         mark_page_accessed(node->page[i]);
 489                 }
 490
 491                 if (test_bit(HFS_BNODE_DELETED, &node->flags)) {
 492                         hfs_bnode_unhash(node);
 493                         spin_unlock(&tree->hash_lock);
 494                         hfs_bmap_free(node);
 495                         hfs_bnode_free(node);
 496                         return;
 497                 }
 498                 spin_unlock(&tree->hash_lock);
 499         }
 500 }