/* * linux/fs/hfsplus/btree.c * * Copyright (C) 2001 * Brad Boyer (flar@allandria.com) * (C) 2003 Ardis Technologies <roman@ardistech.com> * * Handle opening/closing btree */ #include <linux/slab.h> #include <linux/pagemap.h> #include "hfsplus_fs.h" #include "hfsplus_raw.h" /* Get a reference to a B*Tree and do some initial checks */ struct hfs_btree *hfs_btree_open(struct super_block *sb, u32 id) { struct hfs_btree *tree; struct hfs_btree_header_rec *head; struct address_space *mapping; struct page *page; unsigned int size; tree = kmalloc(sizeof(*tree), GFP_KERNEL); if (!tree) return NULL; memset(tree, 0, sizeof(*tree)); init_MUTEX(&tree->tree_lock); spin_lock_init(&tree->hash_lock); /* Set the correct compare function */ tree->sb = sb; tree->cnid = id; if (id == HFSPLUS_EXT_CNID) { tree->keycmp = hfsplus_ext_cmp_key; } else if (id == HFSPLUS_CAT_CNID) { tree->keycmp = hfsplus_cat_cmp_key; } else { printk("HFS+-fs: unknown B*Tree requested\n"); goto free_tree; } tree->inode = iget(sb, id); if (!tree->inode) goto free_tree; mapping = tree->inode->i_mapping; page = read_cache_page(mapping, 0, (filler_t *)mapping->a_ops->readpage, NULL); if (IS_ERR(page)) goto free_tree; /* Load the header */ head = (struct hfs_btree_header_rec *)(kmap(page) + sizeof(struct hfs_bnode_desc)); tree->root = be32_to_cpu(head->root); tree->leaf_count = be32_to_cpu(head->leaf_count); tree->leaf_head = be32_to_cpu(head->leaf_head); tree->leaf_tail = be32_to_cpu(head->leaf_tail); tree->node_count = be32_to_cpu(head->node_count); tree->free_nodes = be32_to_cpu(head->free_nodes); tree->attributes = be32_to_cpu(head->attributes); tree->node_size = be16_to_cpu(head->node_size); tree->max_key_len = be16_to_cpu(head->max_key_len); tree->depth = be16_to_cpu(head->depth); size = tree->node_size; if (!size || size & (size - 1)) goto fail_page; if (!tree->node_count) goto fail_page; tree->node_size_shift = ffs(size) - 1; tree->pages_per_bnode = (tree->node_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; kunmap(page); page_cache_release(page); return tree; fail_page: tree->inode->i_mapping->a_ops = &hfsplus_aops; page_cache_release(page); free_tree: iput(tree->inode); kfree(tree); return NULL; } /* Release resources used by a btree */ void hfs_btree_close(struct hfs_btree *tree) { struct hfs_bnode *node; int i; if (!tree) return; for (i = 0; i < NODE_HASH_SIZE; i++) { while ((node = tree->node_hash[i])) { tree->node_hash[i] = node->next_hash; if (atomic_read(&node->refcnt)) printk("HFS+: node %d:%d still has %d user(s)!\n", node->tree->cnid, node->this, atomic_read(&node->refcnt)); hfs_bnode_free(node); tree->node_hash_cnt--; } } iput(tree->inode); kfree(tree); } void hfs_btree_write(struct hfs_btree *tree) { struct hfs_btree_header_rec *head; struct hfs_bnode *node; struct page *page; node = hfs_bnode_find(tree, 0); if (IS_ERR(node)) /* panic? */ return; /* Load the header */ page = node->page[0]; head = (struct hfs_btree_header_rec *)(kmap(page) + sizeof(struct hfs_bnode_desc)); head->root = cpu_to_be32(tree->root); head->leaf_count = cpu_to_be32(tree->leaf_count); head->leaf_head = cpu_to_be32(tree->leaf_head); head->leaf_tail = cpu_to_be32(tree->leaf_tail); head->node_count = cpu_to_be32(tree->node_count); head->free_nodes = cpu_to_be32(tree->free_nodes); head->attributes = cpu_to_be32(tree->attributes); head->depth = cpu_to_be16(tree->depth); kunmap(page); set_page_dirty(page); hfs_bnode_put(node); } static struct hfs_bnode *hfs_bmap_new_bmap(struct hfs_bnode *prev, u32 idx) { struct hfs_btree *tree = prev->tree; struct hfs_bnode *node; struct hfs_bnode_desc desc; __be32 cnid; node = hfs_bnode_create(tree, idx); if (IS_ERR(node)) return node; tree->free_nodes--; prev->next = idx; cnid = cpu_to_be32(idx); hfs_bnode_write(prev, &cnid, offsetof(struct hfs_bnode_desc, next), 4); node->type = HFS_NODE_MAP; node->num_recs = 1; hfs_bnode_clear(node, 0, tree->node_size); desc.next = 0; desc.prev = 0; desc.type = HFS_NODE_MAP; desc.height = 0; desc.num_recs = cpu_to_be16(1); desc.reserved = 0; hfs_bnode_write(node, &desc, 0, sizeof(desc)); hfs_bnode_write_u16(node, 14, 0x8000); hfs_bnode_write_u16(node, tree->node_size - 2, 14); hfs_bnode_write_u16(node, tree->node_size - 4, tree->node_size - 6); return node; } struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree) { struct hfs_bnode *node, *next_node; struct page **pagep; u32 nidx, idx; u16 off, len; u8 *data, byte, m; int i; while (!tree->free_nodes) { struct inode *inode = tree->inode; u32 count; int res; res = hfsplus_file_extend(inode); if (res) return ERR_PTR(res); HFSPLUS_I(inode).phys_size = inode->i_size = (loff_t)HFSPLUS_I(inode).alloc_blocks << HFSPLUS_SB(tree->sb).alloc_blksz_shift; HFSPLUS_I(inode).fs_blocks = HFSPLUS_I(inode).alloc_blocks << HFSPLUS_SB(tree->sb).fs_shift; inode_set_bytes(inode, inode->i_size); count = inode->i_size >> tree->node_size_shift; tree->free_nodes = count - tree->node_count; tree->node_count = count; } nidx = 0; node = hfs_bnode_find(tree, nidx); if (IS_ERR(node)) return node; len = hfs_brec_lenoff(node, 2, &off); off += node->page_offset; pagep = node->page + (off >> PAGE_CACHE_SHIFT); data = kmap(*pagep); off &= ~PAGE_CACHE_MASK; idx = 0; for (;;) { while (len) { byte = data[off]; if (byte != 0xff) { for (m = 0x80, i = 0; i < 8; m >>= 1, i++) { if (!(byte & m)) { idx += i; data[off] |= m; set_page_dirty(*pagep); kunmap(*pagep); tree->free_nodes--; mark_inode_dirty(tree->inode); hfs_bnode_put(node); if (!idx) { printk("unexpected idx %u (%u)\n", idx, node->this); BUG(); } return hfs_bnode_create(tree, idx); } } } if (++off >= PAGE_CACHE_SIZE) { kunmap(*pagep); data = kmap(*++pagep); off = 0; } idx += 8; len--; } kunmap(*pagep); nidx = node->next; if (!nidx) { printk("create new bmap node...\n"); next_node = hfs_bmap_new_bmap(node, idx); } else next_node = hfs_bnode_find(tree, nidx); hfs_bnode_put(node); if (IS_ERR(next_node)) return next_node; node = next_node; len = hfs_brec_lenoff(node, 0, &off); off += node->page_offset; pagep = node->page + (off >> PAGE_CACHE_SHIFT); data = kmap(*pagep); off &= ~PAGE_CACHE_MASK; } } void hfs_bmap_free(struct hfs_bnode *node) { struct hfs_btree *tree; struct page *page; u16 off, len; u32 nidx; u8 *data, byte, m; dprint(DBG_BNODE_MOD, "btree_free_node: %u\n", node->this); if (!node->this) BUG(); tree = node->tree; nidx = node->this; node = hfs_bnode_find(tree, 0); if (IS_ERR(node)) return; len = hfs_brec_lenoff(node, 2, &off); while (nidx >= len * 8) { u32 i; nidx -= len * 8; i = node->next; hfs_bnode_put(node); if (!i) { /* panic */; printk("HFS: unable to free bnode %u. bmap not found!\n", node->this); return; } node = hfs_bnode_find(tree, i); if (IS_ERR(node)) return; if (node->type != HFS_NODE_MAP) { /* panic */; printk("HFS: invalid bmap found! (%u,%d)\n", node->this, node->type); hfs_bnode_put(node); return; } len = hfs_brec_lenoff(node, 0, &off); } off += node->page_offset + nidx / 8; page = node->page[off >> PAGE_CACHE_SHIFT]; data = kmap(page); off &= ~PAGE_CACHE_MASK; m = 1 << (~nidx & 7); byte = data[off]; if (!(byte & m)) { printk("HFS: trying to free free bnode %u(%d)\n", node->this, node->type); kunmap(page); hfs_bnode_put(node); return; } data[off] = byte & ~m; set_page_dirty(page); kunmap(page); hfs_bnode_put(node); tree->free_nodes++; mark_inode_dirty(tree->inode); }