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 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 }