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_local_page(page) +
  84                                                sizeof(struct hfs_bnode_desc));
  85         tree->root = be32_to_cpu(head->root);
  86         tree->leaf_count = be32_to_cpu(head->leaf_count);
  87         tree->leaf_head = be32_to_cpu(head->leaf_head);
  88         tree->leaf_tail = be32_to_cpu(head->leaf_tail);
  89         tree->node_count = be32_to_cpu(head->node_count);
  90         tree->free_nodes = be32_to_cpu(head->free_nodes);
  91         tree->attributes = be32_to_cpu(head->attributes);
  92         tree->node_size = be16_to_cpu(head->node_size);
  93         tree->max_key_len = be16_to_cpu(head->max_key_len);
  94         tree->depth = be16_to_cpu(head->depth);
  95
  96         size = tree->node_size;
  97         if (!is_power_of_2(size))
  98                 goto fail_page;
  99         if (!tree->node_count)
 100                 goto fail_page;
 101         switch (id) {
 102         case HFS_EXT_CNID:
 103                 if (tree->max_key_len != HFS_MAX_EXT_KEYLEN) {
 104                         pr_err("invalid extent max_key_len %d\n",
 105                                tree->max_key_len);
 106                         goto fail_page;
 107                 }
 108                 break;
 109         case HFS_CAT_CNID:
 110                 if (tree->max_key_len != HFS_MAX_CAT_KEYLEN) {
 111                         pr_err("invalid catalog max_key_len %d\n",
 112                                tree->max_key_len);
 113                         goto fail_page;
 114                 }
 115                 break;
 116         default:
 117                 BUG();
 118         }
 119
 120         tree->node_size_shift = ffs(size) - 1;
 121         tree->pages_per_bnode = (tree->node_size + PAGE_SIZE - 1) >> PAGE_SHIFT;
 122
 123         kunmap_local(head);
 124         put_page(page);
 125         return tree;
 126
 127 fail_page:
 128         kunmap_local(head);
 129         put_page(page);
 130 free_inode:
 131         tree->inode->i_mapping->a_ops = &hfs_aops;
 132         iput(tree->inode);
 133 free_tree:
 134         kfree(tree);
 135         return NULL;
 136 }
 137
 138 /* Release resources used by a btree */
 139 void hfs_btree_close(struct hfs_btree *tree)
 140 {
 141         struct hfs_bnode *node;
 142         int i;
 143
 144         if (!tree)
 145                 return;
 146
 147         for (i = 0; i < NODE_HASH_SIZE; i++) {
 148                 while ((node = tree->node_hash[i])) {
 149                         tree->node_hash[i] = node->next_hash;
 150                         if (atomic_read(&node->refcnt))
 151                                 pr_err("node %d:%d still has %d user(s)!\n",
 152                                        node->tree->cnid, node->this,
 153                                        atomic_read(&node->refcnt));
 154                         hfs_bnode_free(node);
 155                         tree->node_hash_cnt--;
 156                 }
 157         }
 158         iput(tree->inode);
 159         kfree(tree);
 160 }
 161
 162 void hfs_btree_write(struct hfs_btree *tree)
 163 {
 164         struct hfs_btree_header_rec *head;
 165         struct hfs_bnode *node;
 166         struct page *page;
 167
 168         node = hfs_bnode_find(tree, 0);
 169         if (IS_ERR(node))
 170                 /* panic? */
 171                 return;
 172         /* Load the header */
 173         page = node->page[0];
 174         head = (struct hfs_btree_header_rec *)(kmap_local_page(page) +
 175                                                sizeof(struct hfs_bnode_desc));
 176
 177         head->root = cpu_to_be32(tree->root);
 178         head->leaf_count = cpu_to_be32(tree->leaf_count);
 179         head->leaf_head = cpu_to_be32(tree->leaf_head);
 180         head->leaf_tail = cpu_to_be32(tree->leaf_tail);
 181         head->node_count = cpu_to_be32(tree->node_count);
 182         head->free_nodes = cpu_to_be32(tree->free_nodes);
 183         head->attributes = cpu_to_be32(tree->attributes);
 184         head->depth = cpu_to_be16(tree->depth);
 185
 186         kunmap_local(head);
 187         set_page_dirty(page);
 188         hfs_bnode_put(node);
 189 }
 190
 191 static struct hfs_bnode *hfs_bmap_new_bmap(struct hfs_bnode *prev, u32 idx)
 192 {
 193         struct hfs_btree *tree = prev->tree;
 194         struct hfs_bnode *node;
 195         struct hfs_bnode_desc desc;
 196         __be32 cnid;
 197
 198         node = hfs_bnode_create(tree, idx);
 199         if (IS_ERR(node))
 200                 return node;
 201
 202         if (!tree->free_nodes)
 203                 panic("FIXME!!!");
 204         tree->free_nodes--;
 205         prev->next = idx;
 206         cnid = cpu_to_be32(idx);
 207         hfs_bnode_write(prev, &cnid, offsetof(struct hfs_bnode_desc, next), 4);
 208
 209         node->type = HFS_NODE_MAP;
 210         node->num_recs = 1;
 211         hfs_bnode_clear(node, 0, tree->node_size);
 212         desc.next = 0;
 213         desc.prev = 0;
 214         desc.type = HFS_NODE_MAP;
 215         desc.height = 0;
 216         desc.num_recs = cpu_to_be16(1);
 217         desc.reserved = 0;
 218         hfs_bnode_write(node, &desc, 0, sizeof(desc));
 219         hfs_bnode_write_u16(node, 14, 0x8000);
 220         hfs_bnode_write_u16(node, tree->node_size - 2, 14);
 221         hfs_bnode_write_u16(node, tree->node_size - 4, tree->node_size - 6);
 222
 223         return node;
 224 }
 225
 226 /* Make sure @tree has enough space for the @rsvd_nodes */
 227 int hfs_bmap_reserve(struct hfs_btree *tree, int rsvd_nodes)
 228 {
 229         struct inode *inode = tree->inode;
 230         u32 count;
 231         int res;
 232
 233         while (tree->free_nodes < rsvd_nodes) {
 234                 res = hfs_extend_file(inode);
 235                 if (res)
 236                         return res;
 237                 HFS_I(inode)->phys_size = inode->i_size =
 238                                 (loff_t)HFS_I(inode)->alloc_blocks *
 239                                 HFS_SB(tree->sb)->alloc_blksz;
 240                 HFS_I(inode)->fs_blocks = inode->i_size >>
 241                                           tree->sb->s_blocksize_bits;
 242                 inode_set_bytes(inode, inode->i_size);
 243                 count = inode->i_size >> tree->node_size_shift;
 244                 tree->free_nodes += count - tree->node_count;
 245                 tree->node_count = count;
 246         }
 247         return 0;
 248 }
 249
 250 struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree)
 251 {
 252         struct hfs_bnode *node, *next_node;
 253         struct page **pagep;
 254         u32 nidx, idx;
 255         unsigned off;
 256         u16 off16;
 257         u16 len;
 258         u8 *data, byte, m;
 259         int i, res;
 260
 261         res = hfs_bmap_reserve(tree, 1);
 262         if (res)
 263                 return ERR_PTR(res);
 264
 265         nidx = 0;
 266         node = hfs_bnode_find(tree, nidx);
 267         if (IS_ERR(node))
 268                 return node;
 269         len = hfs_brec_lenoff(node, 2, &off16);
 270         off = off16;
 271
 272         off += node->page_offset;
 273         pagep = node->page + (off >> PAGE_SHIFT);
 274         data = kmap_local_page(*pagep);
 275         off &= ~PAGE_MASK;
 276         idx = 0;
 277
 278         for (;;) {
 279                 while (len) {
 280                         byte = data[off];
 281                         if (byte != 0xff) {
 282                                 for (m = 0x80, i = 0; i < 8; m >>= 1, i++) {
 283                                         if (!(byte & m)) {
 284                                                 idx += i;
 285                                                 data[off] |= m;
 286                                                 set_page_dirty(*pagep);
 287                                                 kunmap_local(data);
 288                                                 tree->free_nodes--;
 289                                                 mark_inode_dirty(tree->inode);
 290                                                 hfs_bnode_put(node);
 291                                                 return hfs_bnode_create(tree, idx);
 292                                         }
 293                                 }
 294                         }
 295                         if (++off >= PAGE_SIZE) {
 296                                 kunmap_local(data);
 297                                 data = kmap_local_page(*++pagep);
 298                                 off = 0;
 299                         }
 300                         idx += 8;
 301                         len--;
 302                 }
 303                 kunmap_local(data);
 304                 nidx = node->next;
 305                 if (!nidx) {
 306                         printk(KERN_DEBUG "create new bmap node...\n");
 307                         next_node = hfs_bmap_new_bmap(node, idx);
 308                 } else
 309                         next_node = hfs_bnode_find(tree, nidx);
 310                 hfs_bnode_put(node);
 311                 if (IS_ERR(next_node))
 312                         return next_node;
 313                 node = next_node;
 314
 315                 len = hfs_brec_lenoff(node, 0, &off16);
 316                 off = off16;
 317                 off += node->page_offset;
 318                 pagep = node->page + (off >> PAGE_SHIFT);
 319                 data = kmap_local_page(*pagep);
 320                 off &= ~PAGE_MASK;
 321         }
 322 }
 323
 324 void hfs_bmap_free(struct hfs_bnode *node)
 325 {
 326         struct hfs_btree *tree;
 327         struct page *page;
 328         u16 off, len;
 329         u32 nidx;
 330         u8 *data, byte, m;
 331
 332         hfs_dbg(BNODE_MOD, "btree_free_node: %u\n", node->this);
 333         tree = node->tree;
 334         nidx = node->this;
 335         node = hfs_bnode_find(tree, 0);
 336         if (IS_ERR(node))
 337                 return;
 338         len = hfs_brec_lenoff(node, 2, &off);
 339         while (nidx >= len * 8) {
 340                 u32 i;
 341
 342                 nidx -= len * 8;
 343                 i = node->next;
 344                 if (!i) {
 345                         /* panic */;
 346                         pr_crit("unable to free bnode %u. bmap not found!\n",
 347                                 node->this);
 348                         hfs_bnode_put(node);
 349                         return;
 350                 }
 351                 hfs_bnode_put(node);
 352                 node = hfs_bnode_find(tree, i);
 353                 if (IS_ERR(node))
 354                         return;
 355                 if (node->type != HFS_NODE_MAP) {
 356                         /* panic */;
 357                         pr_crit("invalid bmap found! (%u,%d)\n",
 358                                 node->this, node->type);
 359                         hfs_bnode_put(node);
 360                         return;
 361                 }
 362                 len = hfs_brec_lenoff(node, 0, &off);
 363         }
 364         off += node->page_offset + nidx / 8;
 365         page = node->page[off >> PAGE_SHIFT];
 366         data = kmap_local_page(page);
 367         off &= ~PAGE_MASK;
 368         m = 1 << (~nidx & 7);
 369         byte = data[off];
 370         if (!(byte & m)) {
 371                 pr_crit("trying to free free bnode %u(%d)\n",
 372                         node->this, node->type);
 373                 kunmap_local(data);
 374                 hfs_bnode_put(node);
 375                 return;
 376         }
 377         data[off] = byte & ~m;
 378         set_page_dirty(page);
 379         kunmap_local(data);
 380         hfs_bnode_put(node);
 381         tree->free_nodes++;
 382         mark_inode_dirty(tree->inode);
 383 }