btree.c (9089B)
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 */ 19struct 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 126fail_page: 127 put_page(page); 128free_inode: 129 tree->inode->i_mapping->a_ops = &hfs_aops; 130 iput(tree->inode); 131free_tree: 132 kfree(tree); 133 return NULL; 134} 135 136/* Release resources used by a btree */ 137void 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 160void 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 188static 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/* Make sure @tree has enough space for the @rsvd_nodes */ 224int hfs_bmap_reserve(struct hfs_btree *tree, int rsvd_nodes) 225{ 226 struct inode *inode = tree->inode; 227 u32 count; 228 int res; 229 230 while (tree->free_nodes < rsvd_nodes) { 231 res = hfs_extend_file(inode); 232 if (res) 233 return res; 234 HFS_I(inode)->phys_size = inode->i_size = 235 (loff_t)HFS_I(inode)->alloc_blocks * 236 HFS_SB(tree->sb)->alloc_blksz; 237 HFS_I(inode)->fs_blocks = inode->i_size >> 238 tree->sb->s_blocksize_bits; 239 inode_set_bytes(inode, inode->i_size); 240 count = inode->i_size >> tree->node_size_shift; 241 tree->free_nodes += count - tree->node_count; 242 tree->node_count = count; 243 } 244 return 0; 245} 246 247struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree) 248{ 249 struct hfs_bnode *node, *next_node; 250 struct page **pagep; 251 u32 nidx, idx; 252 unsigned off; 253 u16 off16; 254 u16 len; 255 u8 *data, byte, m; 256 int i, res; 257 258 res = hfs_bmap_reserve(tree, 1); 259 if (res) 260 return ERR_PTR(res); 261 262 nidx = 0; 263 node = hfs_bnode_find(tree, nidx); 264 if (IS_ERR(node)) 265 return node; 266 len = hfs_brec_lenoff(node, 2, &off16); 267 off = off16; 268 269 off += node->page_offset; 270 pagep = node->page + (off >> PAGE_SHIFT); 271 data = kmap(*pagep); 272 off &= ~PAGE_MASK; 273 idx = 0; 274 275 for (;;) { 276 while (len) { 277 byte = data[off]; 278 if (byte != 0xff) { 279 for (m = 0x80, i = 0; i < 8; m >>= 1, i++) { 280 if (!(byte & m)) { 281 idx += i; 282 data[off] |= m; 283 set_page_dirty(*pagep); 284 kunmap(*pagep); 285 tree->free_nodes--; 286 mark_inode_dirty(tree->inode); 287 hfs_bnode_put(node); 288 return hfs_bnode_create(tree, idx); 289 } 290 } 291 } 292 if (++off >= PAGE_SIZE) { 293 kunmap(*pagep); 294 data = kmap(*++pagep); 295 off = 0; 296 } 297 idx += 8; 298 len--; 299 } 300 kunmap(*pagep); 301 nidx = node->next; 302 if (!nidx) { 303 printk(KERN_DEBUG "create new bmap node...\n"); 304 next_node = hfs_bmap_new_bmap(node, idx); 305 } else 306 next_node = hfs_bnode_find(tree, nidx); 307 hfs_bnode_put(node); 308 if (IS_ERR(next_node)) 309 return next_node; 310 node = next_node; 311 312 len = hfs_brec_lenoff(node, 0, &off16); 313 off = off16; 314 off += node->page_offset; 315 pagep = node->page + (off >> PAGE_SHIFT); 316 data = kmap(*pagep); 317 off &= ~PAGE_MASK; 318 } 319} 320 321void hfs_bmap_free(struct hfs_bnode *node) 322{ 323 struct hfs_btree *tree; 324 struct page *page; 325 u16 off, len; 326 u32 nidx; 327 u8 *data, byte, m; 328 329 hfs_dbg(BNODE_MOD, "btree_free_node: %u\n", node->this); 330 tree = node->tree; 331 nidx = node->this; 332 node = hfs_bnode_find(tree, 0); 333 if (IS_ERR(node)) 334 return; 335 len = hfs_brec_lenoff(node, 2, &off); 336 while (nidx >= len * 8) { 337 u32 i; 338 339 nidx -= len * 8; 340 i = node->next; 341 if (!i) { 342 /* panic */; 343 pr_crit("unable to free bnode %u. bmap not found!\n", 344 node->this); 345 hfs_bnode_put(node); 346 return; 347 } 348 hfs_bnode_put(node); 349 node = hfs_bnode_find(tree, i); 350 if (IS_ERR(node)) 351 return; 352 if (node->type != HFS_NODE_MAP) { 353 /* panic */; 354 pr_crit("invalid bmap found! (%u,%d)\n", 355 node->this, node->type); 356 hfs_bnode_put(node); 357 return; 358 } 359 len = hfs_brec_lenoff(node, 0, &off); 360 } 361 off += node->page_offset + nidx / 8; 362 page = node->page[off >> PAGE_SHIFT]; 363 data = kmap(page); 364 off &= ~PAGE_MASK; 365 m = 1 << (~nidx & 7); 366 byte = data[off]; 367 if (!(byte & m)) { 368 pr_crit("trying to free free bnode %u(%d)\n", 369 node->this, node->type); 370 kunmap(page); 371 hfs_bnode_put(node); 372 return; 373 } 374 data[off] = byte & ~m; 375 set_page_dirty(page); 376 kunmap(page); 377 hfs_bnode_put(node); 378 tree->free_nodes++; 379 mark_inode_dirty(tree->inode); 380}