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![Pan Bian](/assets/img/avatar_default.png)
hfs_bmap_free() frees node via hfs_bnode_put(node). However it then reads node->this when dumping error message on an error path, which may result in a use-after-free bug. This patch frees node only when it is never used. Link: http://lkml.kernel.org/r/1543053441-66942-1-git-send-email-bianpan2016@163.com Signed-off-by: Pan Bian <bianpan2016@163.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Ernesto A. Fernandez <ernesto.mnd.fernandez@gmail.com> Cc: Joe Perches <joe@perches.com> Cc: Viacheslav Dubeyko <slava@dubeyko.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
511 lines
12 KiB
C
511 lines
12 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* linux/fs/hfsplus/btree.c
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*
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* Copyright (C) 2001
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* Brad Boyer (flar@allandria.com)
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* (C) 2003 Ardis Technologies <roman@ardistech.com>
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*
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* Handle opening/closing btree
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*/
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#include <linux/slab.h>
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#include <linux/pagemap.h>
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#include <linux/log2.h>
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#include "hfsplus_fs.h"
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#include "hfsplus_raw.h"
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/*
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* Initial source code of clump size calculation is gotten
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* from http://opensource.apple.com/tarballs/diskdev_cmds/
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*/
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#define CLUMP_ENTRIES 15
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static short clumptbl[CLUMP_ENTRIES * 3] = {
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/*
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* Volume Attributes Catalog Extents
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* Size Clump (MB) Clump (MB) Clump (MB)
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*/
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/* 1GB */ 4, 4, 4,
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/* 2GB */ 6, 6, 4,
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/* 4GB */ 8, 8, 4,
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/* 8GB */ 11, 11, 5,
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/*
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* For volumes 16GB and larger, we want to make sure that a full OS
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* install won't require fragmentation of the Catalog or Attributes
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* B-trees. We do this by making the clump sizes sufficiently large,
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* and by leaving a gap after the B-trees for them to grow into.
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*
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* For SnowLeopard 10A298, a FullNetInstall with all packages selected
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* results in:
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* Catalog B-tree Header
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* nodeSize: 8192
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* totalNodes: 31616
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* freeNodes: 1978
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* (used = 231.55 MB)
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* Attributes B-tree Header
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* nodeSize: 8192
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* totalNodes: 63232
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* freeNodes: 958
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* (used = 486.52 MB)
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*
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* We also want Time Machine backup volumes to have a sufficiently
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* large clump size to reduce fragmentation.
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*
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* The series of numbers for Catalog and Attribute form a geometric
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* series. For Catalog (16GB to 512GB), each term is 8**(1/5) times
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* the previous term. For Attributes (16GB to 512GB), each term is
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* 4**(1/5) times the previous term. For 1TB to 16TB, each term is
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* 2**(1/5) times the previous term.
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*/
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/* 16GB */ 64, 32, 5,
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/* 32GB */ 84, 49, 6,
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/* 64GB */ 111, 74, 7,
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/* 128GB */ 147, 111, 8,
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/* 256GB */ 194, 169, 9,
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/* 512GB */ 256, 256, 11,
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/* 1TB */ 294, 294, 14,
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/* 2TB */ 338, 338, 16,
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/* 4TB */ 388, 388, 20,
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/* 8TB */ 446, 446, 25,
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/* 16TB */ 512, 512, 32
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};
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u32 hfsplus_calc_btree_clump_size(u32 block_size, u32 node_size,
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u64 sectors, int file_id)
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{
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u32 mod = max(node_size, block_size);
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u32 clump_size;
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int column;
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int i;
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/* Figure out which column of the above table to use for this file. */
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switch (file_id) {
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case HFSPLUS_ATTR_CNID:
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column = 0;
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break;
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case HFSPLUS_CAT_CNID:
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column = 1;
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break;
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default:
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column = 2;
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break;
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}
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/*
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* The default clump size is 0.8% of the volume size. And
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* it must also be a multiple of the node and block size.
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*/
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if (sectors < 0x200000) {
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clump_size = sectors << 2; /* 0.8 % */
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if (clump_size < (8 * node_size))
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clump_size = 8 * node_size;
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} else {
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/* turn exponent into table index... */
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for (i = 0, sectors = sectors >> 22;
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sectors && (i < CLUMP_ENTRIES - 1);
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++i, sectors = sectors >> 1) {
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/* empty body */
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}
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clump_size = clumptbl[column + (i) * 3] * 1024 * 1024;
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}
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/*
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* Round the clump size to a multiple of node and block size.
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* NOTE: This rounds down.
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*/
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clump_size /= mod;
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clump_size *= mod;
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/*
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* Rounding down could have rounded down to 0 if the block size was
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* greater than the clump size. If so, just use one block or node.
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*/
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if (clump_size == 0)
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clump_size = mod;
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return clump_size;
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}
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/* Get a reference to a B*Tree and do some initial checks */
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struct hfs_btree *hfs_btree_open(struct super_block *sb, u32 id)
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{
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struct hfs_btree *tree;
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struct hfs_btree_header_rec *head;
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struct address_space *mapping;
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struct inode *inode;
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struct page *page;
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unsigned int size;
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tree = kzalloc(sizeof(*tree), GFP_KERNEL);
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if (!tree)
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return NULL;
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mutex_init(&tree->tree_lock);
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spin_lock_init(&tree->hash_lock);
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tree->sb = sb;
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tree->cnid = id;
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inode = hfsplus_iget(sb, id);
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if (IS_ERR(inode))
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goto free_tree;
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tree->inode = inode;
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if (!HFSPLUS_I(tree->inode)->first_blocks) {
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pr_err("invalid btree extent records (0 size)\n");
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goto free_inode;
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}
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mapping = tree->inode->i_mapping;
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page = read_mapping_page(mapping, 0, NULL);
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if (IS_ERR(page))
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goto free_inode;
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/* Load the header */
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head = (struct hfs_btree_header_rec *)(kmap(page) +
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sizeof(struct hfs_bnode_desc));
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tree->root = be32_to_cpu(head->root);
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tree->leaf_count = be32_to_cpu(head->leaf_count);
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tree->leaf_head = be32_to_cpu(head->leaf_head);
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tree->leaf_tail = be32_to_cpu(head->leaf_tail);
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tree->node_count = be32_to_cpu(head->node_count);
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tree->free_nodes = be32_to_cpu(head->free_nodes);
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tree->attributes = be32_to_cpu(head->attributes);
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tree->node_size = be16_to_cpu(head->node_size);
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tree->max_key_len = be16_to_cpu(head->max_key_len);
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tree->depth = be16_to_cpu(head->depth);
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/* Verify the tree and set the correct compare function */
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switch (id) {
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case HFSPLUS_EXT_CNID:
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if (tree->max_key_len != HFSPLUS_EXT_KEYLEN - sizeof(u16)) {
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pr_err("invalid extent max_key_len %d\n",
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tree->max_key_len);
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goto fail_page;
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}
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if (tree->attributes & HFS_TREE_VARIDXKEYS) {
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pr_err("invalid extent btree flag\n");
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goto fail_page;
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}
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tree->keycmp = hfsplus_ext_cmp_key;
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break;
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case HFSPLUS_CAT_CNID:
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if (tree->max_key_len != HFSPLUS_CAT_KEYLEN - sizeof(u16)) {
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pr_err("invalid catalog max_key_len %d\n",
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tree->max_key_len);
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goto fail_page;
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}
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if (!(tree->attributes & HFS_TREE_VARIDXKEYS)) {
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pr_err("invalid catalog btree flag\n");
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goto fail_page;
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}
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if (test_bit(HFSPLUS_SB_HFSX, &HFSPLUS_SB(sb)->flags) &&
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(head->key_type == HFSPLUS_KEY_BINARY))
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tree->keycmp = hfsplus_cat_bin_cmp_key;
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else {
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tree->keycmp = hfsplus_cat_case_cmp_key;
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set_bit(HFSPLUS_SB_CASEFOLD, &HFSPLUS_SB(sb)->flags);
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}
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break;
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case HFSPLUS_ATTR_CNID:
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if (tree->max_key_len != HFSPLUS_ATTR_KEYLEN - sizeof(u16)) {
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pr_err("invalid attributes max_key_len %d\n",
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tree->max_key_len);
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goto fail_page;
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}
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tree->keycmp = hfsplus_attr_bin_cmp_key;
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break;
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default:
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pr_err("unknown B*Tree requested\n");
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goto fail_page;
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}
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if (!(tree->attributes & HFS_TREE_BIGKEYS)) {
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pr_err("invalid btree flag\n");
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goto fail_page;
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}
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size = tree->node_size;
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if (!is_power_of_2(size))
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goto fail_page;
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if (!tree->node_count)
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goto fail_page;
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tree->node_size_shift = ffs(size) - 1;
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tree->pages_per_bnode =
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(tree->node_size + PAGE_SIZE - 1) >>
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PAGE_SHIFT;
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kunmap(page);
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put_page(page);
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return tree;
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fail_page:
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put_page(page);
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free_inode:
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tree->inode->i_mapping->a_ops = &hfsplus_aops;
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iput(tree->inode);
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free_tree:
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kfree(tree);
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return NULL;
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}
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/* Release resources used by a btree */
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void hfs_btree_close(struct hfs_btree *tree)
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{
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struct hfs_bnode *node;
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int i;
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if (!tree)
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return;
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for (i = 0; i < NODE_HASH_SIZE; i++) {
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while ((node = tree->node_hash[i])) {
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tree->node_hash[i] = node->next_hash;
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if (atomic_read(&node->refcnt))
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pr_crit("node %d:%d "
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"still has %d user(s)!\n",
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node->tree->cnid, node->this,
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atomic_read(&node->refcnt));
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hfs_bnode_free(node);
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tree->node_hash_cnt--;
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}
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}
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iput(tree->inode);
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kfree(tree);
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}
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int hfs_btree_write(struct hfs_btree *tree)
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{
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struct hfs_btree_header_rec *head;
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struct hfs_bnode *node;
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struct page *page;
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node = hfs_bnode_find(tree, 0);
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if (IS_ERR(node))
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/* panic? */
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return -EIO;
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/* Load the header */
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page = node->page[0];
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head = (struct hfs_btree_header_rec *)(kmap(page) +
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sizeof(struct hfs_bnode_desc));
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head->root = cpu_to_be32(tree->root);
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head->leaf_count = cpu_to_be32(tree->leaf_count);
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head->leaf_head = cpu_to_be32(tree->leaf_head);
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head->leaf_tail = cpu_to_be32(tree->leaf_tail);
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head->node_count = cpu_to_be32(tree->node_count);
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head->free_nodes = cpu_to_be32(tree->free_nodes);
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head->attributes = cpu_to_be32(tree->attributes);
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head->depth = cpu_to_be16(tree->depth);
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kunmap(page);
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set_page_dirty(page);
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hfs_bnode_put(node);
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return 0;
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}
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static struct hfs_bnode *hfs_bmap_new_bmap(struct hfs_bnode *prev, u32 idx)
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{
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struct hfs_btree *tree = prev->tree;
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struct hfs_bnode *node;
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struct hfs_bnode_desc desc;
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__be32 cnid;
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node = hfs_bnode_create(tree, idx);
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if (IS_ERR(node))
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return node;
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tree->free_nodes--;
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prev->next = idx;
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cnid = cpu_to_be32(idx);
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hfs_bnode_write(prev, &cnid, offsetof(struct hfs_bnode_desc, next), 4);
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node->type = HFS_NODE_MAP;
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node->num_recs = 1;
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hfs_bnode_clear(node, 0, tree->node_size);
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desc.next = 0;
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desc.prev = 0;
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desc.type = HFS_NODE_MAP;
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desc.height = 0;
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desc.num_recs = cpu_to_be16(1);
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desc.reserved = 0;
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hfs_bnode_write(node, &desc, 0, sizeof(desc));
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hfs_bnode_write_u16(node, 14, 0x8000);
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hfs_bnode_write_u16(node, tree->node_size - 2, 14);
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hfs_bnode_write_u16(node, tree->node_size - 4, tree->node_size - 6);
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return node;
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}
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/* Make sure @tree has enough space for the @rsvd_nodes */
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int hfs_bmap_reserve(struct hfs_btree *tree, int rsvd_nodes)
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{
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struct inode *inode = tree->inode;
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struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
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u32 count;
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int res;
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if (rsvd_nodes <= 0)
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return 0;
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while (tree->free_nodes < rsvd_nodes) {
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res = hfsplus_file_extend(inode, hfs_bnode_need_zeroout(tree));
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if (res)
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return res;
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hip->phys_size = inode->i_size =
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(loff_t)hip->alloc_blocks <<
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HFSPLUS_SB(tree->sb)->alloc_blksz_shift;
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hip->fs_blocks =
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hip->alloc_blocks << HFSPLUS_SB(tree->sb)->fs_shift;
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inode_set_bytes(inode, inode->i_size);
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count = inode->i_size >> tree->node_size_shift;
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tree->free_nodes += count - tree->node_count;
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tree->node_count = count;
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}
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return 0;
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}
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struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree)
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{
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struct hfs_bnode *node, *next_node;
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struct page **pagep;
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u32 nidx, idx;
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unsigned off;
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u16 off16;
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u16 len;
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u8 *data, byte, m;
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int i, res;
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res = hfs_bmap_reserve(tree, 1);
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if (res)
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return ERR_PTR(res);
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nidx = 0;
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node = hfs_bnode_find(tree, nidx);
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if (IS_ERR(node))
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return node;
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len = hfs_brec_lenoff(node, 2, &off16);
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off = off16;
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off += node->page_offset;
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pagep = node->page + (off >> PAGE_SHIFT);
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data = kmap(*pagep);
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off &= ~PAGE_MASK;
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idx = 0;
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for (;;) {
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while (len) {
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byte = data[off];
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if (byte != 0xff) {
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for (m = 0x80, i = 0; i < 8; m >>= 1, i++) {
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if (!(byte & m)) {
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idx += i;
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data[off] |= m;
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set_page_dirty(*pagep);
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kunmap(*pagep);
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tree->free_nodes--;
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mark_inode_dirty(tree->inode);
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hfs_bnode_put(node);
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return hfs_bnode_create(tree,
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idx);
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}
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}
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}
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if (++off >= PAGE_SIZE) {
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kunmap(*pagep);
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data = kmap(*++pagep);
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off = 0;
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}
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idx += 8;
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len--;
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}
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kunmap(*pagep);
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nidx = node->next;
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if (!nidx) {
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hfs_dbg(BNODE_MOD, "create new bmap node\n");
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next_node = hfs_bmap_new_bmap(node, idx);
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} else
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next_node = hfs_bnode_find(tree, nidx);
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hfs_bnode_put(node);
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if (IS_ERR(next_node))
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return next_node;
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node = next_node;
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len = hfs_brec_lenoff(node, 0, &off16);
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off = off16;
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off += node->page_offset;
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pagep = node->page + (off >> PAGE_SHIFT);
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data = kmap(*pagep);
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off &= ~PAGE_MASK;
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}
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}
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void hfs_bmap_free(struct hfs_bnode *node)
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{
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struct hfs_btree *tree;
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struct page *page;
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u16 off, len;
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u32 nidx;
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u8 *data, byte, m;
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hfs_dbg(BNODE_MOD, "btree_free_node: %u\n", node->this);
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BUG_ON(!node->this);
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tree = node->tree;
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nidx = node->this;
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node = hfs_bnode_find(tree, 0);
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if (IS_ERR(node))
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return;
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len = hfs_brec_lenoff(node, 2, &off);
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while (nidx >= len * 8) {
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u32 i;
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nidx -= len * 8;
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i = node->next;
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if (!i) {
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/* panic */;
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pr_crit("unable to free bnode %u. "
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"bmap not found!\n",
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node->this);
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hfs_bnode_put(node);
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return;
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}
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hfs_bnode_put(node);
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node = hfs_bnode_find(tree, i);
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if (IS_ERR(node))
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return;
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if (node->type != HFS_NODE_MAP) {
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/* panic */;
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pr_crit("invalid bmap found! "
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"(%u,%d)\n",
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node->this, node->type);
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hfs_bnode_put(node);
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return;
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}
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len = hfs_brec_lenoff(node, 0, &off);
|
|
}
|
|
off += node->page_offset + nidx / 8;
|
|
page = node->page[off >> PAGE_SHIFT];
|
|
data = kmap(page);
|
|
off &= ~PAGE_MASK;
|
|
m = 1 << (~nidx & 7);
|
|
byte = data[off];
|
|
if (!(byte & m)) {
|
|
pr_crit("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);
|
|
}
|