fs/hfs/btree.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  linux/fs/hfs/btree.c
   4  *
   5  * Copyright (C) 2001
   6  * Brad Boyer (flar@allandria.com)
   7  * (C) 2003 Ardis Technologies <roman@ardistech.com>
   8  *
   9  * Handle opening/closing btree
  10  */
  11
  12 #include <linux/pagemap.h>
  13 #include <linux/slab.h>
  14 #include <linux/log2.h>
  15
  16 #include "btree.h"
  17
  18 /* Get a reference to a B*Tree and do some initial checks */
  19 struct hfs_btree *hfs_btree_open(struct super_block *sb, u32 id, btree_keycmp keycmp)
  20 {
  21         struct hfs_btree *tree;
  22         struct hfs_btree_header_rec *head;
  23         struct address_space *mapping;
  24         struct page *page;
  25         unsigned int size;
  26
  27         tree = kzalloc(sizeof(*tree), GFP_KERNEL);
  28         if (!tree)
  29                 return NULL;
  30
  31         mutex_init(&tree->tree_lock);
  32         spin_lock_init(&tree->hash_lock);
  33         /* Set the correct compare function */
  34         tree->sb = sb;
  35         tree->cnid = id;
  36         tree->keycmp = keycmp;
  37
  38         tree->inode = iget_locked(sb, id);
  39         if (!tree->inode)
  40                 goto free_tree;
  41         BUG_ON(!(tree->inode->i_state & I_NEW));
  42         {
  43         struct hfs_mdb *mdb = HFS_SB(sb)->mdb;
  44         HFS_I(tree->inode)->flags = 0;
  45         mutex_init(&HFS_I(tree->inode)->extents_lock);
  46         switch (id) {
  47         case HFS_EXT_CNID:
  48                 hfs_inode_read_fork(tree->inode, mdb->drXTExtRec, mdb->drXTFlSize,
  49                                     mdb->drXTFlSize, be32_to_cpu(mdb->drXTClpSiz));
  50                 if (HFS_I(tree->inode)->alloc_blocks >
  51                                         HFS_I(tree->inode)->first_blocks) {
  52                         pr_err("invalid btree extent records\n");
  53                         unlock_new_inode(tree->inode);
  54                         goto free_inode;
  55                 }
  56
  57                 tree->inode->i_mapping->a_ops = &hfs_btree_aops;
  58                 break;
  59         case HFS_CAT_CNID:
  60                 hfs_inode_read_fork(tree->inode, mdb->drCTExtRec, mdb->drCTFlSize,
  61                                     mdb->drCTFlSize, be32_to_cpu(mdb->drCTClpSiz));
  62
  63                 if (!HFS_I(tree->inode)->first_blocks) {
  64                         pr_err("invalid btree extent records (0 size)\n");
  65                         unlock_new_inode(tree->inode);
  66                         goto free_inode;
  67                 }
  68
  69                 tree->inode->i_mapping->a_ops = &hfs_btree_aops;
  70                 break;
  71         default:
  72                 BUG();
  73         }
  74         }
  75         unlock_new_inode(tree->inode);
  76
  77         mapping = tree->inode->i_mapping;
  78         page = read_mapping_page(mapping, 0, NULL);
  79         if (IS_ERR(page))
  80                 goto free_inode;
  81
  82         /* Load the header */
  83         head = (struct hfs_btree_header_rec *)(kmap(page) + sizeof(struct hfs_bnode_desc));
  84         tree->root = be32_to_cpu(head->root);
  85         tree->leaf_count = be32_to_cpu(head->leaf_count);
  86         tree->leaf_head = be32_to_cpu(head->leaf_head);
  87         tree->leaf_tail = be32_to_cpu(head->leaf_tail);
  88         tree->node_count = be32_to_cpu(head->node_count);
  89         tree->free_nodes = be32_to_cpu(head->free_nodes);
  90         tree->attributes = be32_to_cpu(head->attributes);
  91         tree->node_size = be16_to_cpu(head->node_size);
  92         tree->max_key_len = be16_to_cpu(head->max_key_len);
  93         tree->depth = be16_to_cpu(head->depth);
  94
  95         size = tree->node_size;
  96         if (!is_power_of_2(size))
  97                 goto fail_page;
  98         if (!tree->node_count)
  99                 goto fail_page;
 100         switch (id) {
 101         case HFS_EXT_CNID:
 102                 if (tree->max_key_len != HFS_MAX_EXT_KEYLEN) {
 103                         pr_err("invalid extent max_key_len %d\n",
 104                                tree->max_key_len);
 105                         goto fail_page;
 106                 }
 107                 break;
 108         case HFS_CAT_CNID:
 109                 if (tree->max_key_len != HFS_MAX_CAT_KEYLEN) {
 110                         pr_err("invalid catalog max_key_len %d\n",
 111                                tree->max_key_len);
 112                         goto fail_page;
 113                 }
 114                 break;
 115         default:
 116                 BUG();
 117         }
 118
 119         tree->node_size_shift = ffs(size) - 1;
 120         tree->pages_per_bnode = (tree->node_size + PAGE_SIZE - 1) >> PAGE_SHIFT;
 121
 122         kunmap(page);
 123         put_page(page);
 124         return tree;
 125
 126 fail_page:
 127         put_page(page);
 128 free_inode:
 129         tree->inode->i_mapping->a_ops = &hfs_aops;
 130         iput(tree->inode);
 131 free_tree:
 132         kfree(tree);
 133         return NULL;
 134 }
 135
 136 /* Release resources used by a btree */
 137 void hfs_btree_close(struct hfs_btree *tree)
 138 {
 139         struct hfs_bnode *node;
 140         int i;
 141
 142         if (!tree)
 143                 return;
 144
 145         for (i = 0; i < NODE_HASH_SIZE; i++) {
 146                 while ((node = tree->node_hash[i])) {
 147                         tree->node_hash[i] = node->next_hash;
 148                         if (atomic_read(&node->refcnt))
 149                                 pr_err("node %d:%d still has %d user(s)!\n",
 150                                        node->tree->cnid, node->this,
 151                                        atomic_read(&node->refcnt));
 152                         hfs_bnode_free(node);
 153                         tree->node_hash_cnt--;
 154                 }
 155         }
 156         iput(tree->inode);
 157         kfree(tree);
 158 }
 159
 160 void hfs_btree_write(struct hfs_btree *tree)
 161 {
 162         struct hfs_btree_header_rec *head;
 163         struct hfs_bnode *node;
 164         struct page *page;
 165
 166         node = hfs_bnode_find(tree, 0);
 167         if (IS_ERR(node))
 168                 /* panic? */
 169                 return;
 170         /* Load the header */
 171         page = node->page[0];
 172         head = (struct hfs_btree_header_rec *)(kmap(page) + sizeof(struct hfs_bnode_desc));
 173
 174         head->root = cpu_to_be32(tree->root);
 175         head->leaf_count = cpu_to_be32(tree->leaf_count);
 176         head->leaf_head = cpu_to_be32(tree->leaf_head);
 177         head->leaf_tail = cpu_to_be32(tree->leaf_tail);
 178         head->node_count = cpu_to_be32(tree->node_count);
 179         head->free_nodes = cpu_to_be32(tree->free_nodes);
 180         head->attributes = cpu_to_be32(tree->attributes);
 181         head->depth = cpu_to_be16(tree->depth);
 182
 183         kunmap(page);
 184         set_page_dirty(page);
 185         hfs_bnode_put(node);
 186 }
 187
 188 static struct hfs_bnode *hfs_bmap_new_bmap(struct hfs_bnode *prev, u32 idx)
 189 {
 190         struct hfs_btree *tree = prev->tree;
 191         struct hfs_bnode *node;
 192         struct hfs_bnode_desc desc;
 193         __be32 cnid;
 194
 195         node = hfs_bnode_create(tree, idx);
 196         if (IS_ERR(node))
 197                 return node;
 198
 199         if (!tree->free_nodes)
 200                 panic("FIXME!!!");
 201         tree->free_nodes--;
 202         prev->next = idx;
 203         cnid = cpu_to_be32(idx);
 204         hfs_bnode_write(prev, &cnid, offsetof(struct hfs_bnode_desc, next), 4);
 205
 206         node->type = HFS_NODE_MAP;
 207         node->num_recs = 1;
 208         hfs_bnode_clear(node, 0, tree->node_size);
 209         desc.next = 0;
 210         desc.prev = 0;
 211         desc.type = HFS_NODE_MAP;
 212         desc.height = 0;
 213         desc.num_recs = cpu_to_be16(1);
 214         desc.reserved = 0;
 215         hfs_bnode_write(node, &desc, 0, sizeof(desc));
 216         hfs_bnode_write_u16(node, 14, 0x8000);
 217         hfs_bnode_write_u16(node, tree->node_size - 2, 14);
 218         hfs_bnode_write_u16(node, tree->node_size - 4, tree->node_size - 6);
 219
 220         return node;
 221 }
 222
 223 struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree)
 224 {
 225         struct hfs_bnode *node, *next_node;
 226         struct page **pagep;
 227         u32 nidx, idx;
 228         unsigned off;
 229         u16 off16;
 230         u16 len;
 231         u8 *data, byte, m;
 232         int i;
 233
 234         while (!tree->free_nodes) {
 235                 struct inode *inode = tree->inode;
 236                 u32 count;
 237                 int res;
 238
 239                 res = hfs_extend_file(inode);
 240                 if (res)
 241                         return ERR_PTR(res);
 242                 HFS_I(inode)->phys_size = inode->i_size =
 243                                 (loff_t)HFS_I(inode)->alloc_blocks *
 244                                 HFS_SB(tree->sb)->alloc_blksz;
 245                 HFS_I(inode)->fs_blocks = inode->i_size >>
 246                                           tree->sb->s_blocksize_bits;
 247                 inode_set_bytes(inode, inode->i_size);
 248                 count = inode->i_size >> tree->node_size_shift;
 249                 tree->free_nodes = count - tree->node_count;
 250                 tree->node_count = count;
 251         }
 252
 253         nidx = 0;
 254         node = hfs_bnode_find(tree, nidx);
 255         if (IS_ERR(node))
 256                 return node;
 257         len = hfs_brec_lenoff(node, 2, &off16);
 258         off = off16;
 259
 260         off += node->page_offset;
 261         pagep = node->page + (off >> PAGE_SHIFT);
 262         data = kmap(*pagep);
 263         off &= ~PAGE_MASK;
 264         idx = 0;
 265
 266         for (;;) {
 267                 while (len) {
 268                         byte = data[off];
 269                         if (byte != 0xff) {
 270                                 for (m = 0x80, i = 0; i < 8; m >>= 1, i++) {
 271                                         if (!(byte & m)) {
 272                                                 idx += i;
 273                                                 data[off] |= m;
 274                                                 set_page_dirty(*pagep);
 275                                                 kunmap(*pagep);
 276                                                 tree->free_nodes--;
 277                                                 mark_inode_dirty(tree->inode);
 278                                                 hfs_bnode_put(node);
 279                                                 return hfs_bnode_create(tree, idx);
 280                                         }
 281                                 }
 282                         }
 283                         if (++off >= PAGE_SIZE) {
 284                                 kunmap(*pagep);
 285                                 data = kmap(*++pagep);
 286                                 off = 0;
 287                         }
 288                         idx += 8;
 289                         len--;
 290                 }
 291                 kunmap(*pagep);
 292                 nidx = node->next;
 293                 if (!nidx) {
 294                         printk(KERN_DEBUG "create new bmap node...\n");
 295                         next_node = hfs_bmap_new_bmap(node, idx);
 296                 } else
 297                         next_node = hfs_bnode_find(tree, nidx);
 298                 hfs_bnode_put(node);
 299                 if (IS_ERR(next_node))
 300                         return next_node;
 301                 node = next_node;
 302
 303                 len = hfs_brec_lenoff(node, 0, &off16);
 304                 off = off16;
 305                 off += node->page_offset;
 306                 pagep = node->page + (off >> PAGE_SHIFT);
 307                 data = kmap(*pagep);
 308                 off &= ~PAGE_MASK;
 309         }
 310 }
 311
 312 void hfs_bmap_free(struct hfs_bnode *node)
 313 {
 314         struct hfs_btree *tree;
 315         struct page *page;
 316         u16 off, len;
 317         u32 nidx;
 318         u8 *data, byte, m;
 319
 320         hfs_dbg(BNODE_MOD, "btree_free_node: %u\n", node->this);
 321         tree = node->tree;
 322         nidx = node->this;
 323         node = hfs_bnode_find(tree, 0);
 324         if (IS_ERR(node))
 325                 return;
 326         len = hfs_brec_lenoff(node, 2, &off);
 327         while (nidx >= len * 8) {
 328                 u32 i;
 329
 330                 nidx -= len * 8;
 331                 i = node->next;
 332                 hfs_bnode_put(node);
 333                 if (!i) {
 334                         /* panic */;
 335                         pr_crit("unable to free bnode %u. bmap not found!\n",
 336                                 node->this);
 337                         return;
 338                 }
 339                 node = hfs_bnode_find(tree, i);
 340                 if (IS_ERR(node))
 341                         return;
 342                 if (node->type != HFS_NODE_MAP) {
 343                         /* panic */;
 344                         pr_crit("invalid bmap found! (%u,%d)\n",
 345                                 node->this, node->type);
 346                         hfs_bnode_put(node);
 347                         return;
 348                 }
 349                 len = hfs_brec_lenoff(node, 0, &off);
 350         }
 351         off += node->page_offset + nidx / 8;
 352         page = node->page[off >> PAGE_SHIFT];
 353         data = kmap(page);
 354         off &= ~PAGE_MASK;
 355         m = 1 << (~nidx & 7);
 356         byte = data[off];
 357         if (!(byte & m)) {
 358                 pr_crit("trying to free free bnode %u(%d)\n",
 359                         node->this, node->type);
 360                 kunmap(page);
 361                 hfs_bnode_put(node);
 362                 return;
 363         }
 364         data[off] = byte & ~m;
 365         set_page_dirty(page);
 366         kunmap(page);
 367         hfs_bnode_put(node);
 368         tree->free_nodes++;
 369         mark_inode_dirty(tree->inode);
 370 }