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