2005-04-17 05:20:36 +07:00
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/*
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* linux/fs/hfsplus/bfind.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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* Search routines for btrees
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*/
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#include <linux/slab.h>
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#include "hfsplus_fs.h"
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int hfs_find_init(struct hfs_btree *tree, struct hfs_find_data *fd)
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{
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void *ptr;
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fd->tree = tree;
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fd->bnode = NULL;
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ptr = kmalloc(tree->max_key_len * 2 + 4, GFP_KERNEL);
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if (!ptr)
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return -ENOMEM;
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fd->search_key = ptr;
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fd->key = ptr + tree->max_key_len + 2;
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2010-12-16 23:08:38 +07:00
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dprint(DBG_BNODE_REFS, "find_init: %d (%p)\n",
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tree->cnid, __builtin_return_address(0));
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2010-10-01 10:46:52 +07:00
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mutex_lock(&tree->tree_lock);
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2005-04-17 05:20:36 +07:00
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return 0;
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}
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void hfs_find_exit(struct hfs_find_data *fd)
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{
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hfs_bnode_put(fd->bnode);
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kfree(fd->search_key);
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2010-12-16 23:08:38 +07:00
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dprint(DBG_BNODE_REFS, "find_exit: %d (%p)\n",
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fd->tree->cnid, __builtin_return_address(0));
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2010-10-01 10:46:52 +07:00
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mutex_unlock(&fd->tree->tree_lock);
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2005-04-17 05:20:36 +07:00
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fd->tree = NULL;
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}
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/* Find the record in bnode that best matches key (not greater than...)*/
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int __hfs_brec_find(struct hfs_bnode *bnode, struct hfs_find_data *fd)
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{
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int cmpval;
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u16 off, len, keylen;
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int rec;
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int b, e;
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int res;
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b = 0;
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e = bnode->num_recs - 1;
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res = -ENOENT;
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do {
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rec = (e + b) / 2;
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len = hfs_brec_lenoff(bnode, rec, &off);
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keylen = hfs_brec_keylen(bnode, rec);
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2010-10-14 20:53:48 +07:00
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if (keylen == 0) {
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res = -EINVAL;
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goto fail;
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}
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2005-04-17 05:20:36 +07:00
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hfs_bnode_read(bnode, fd->key, off, keylen);
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cmpval = bnode->tree->keycmp(fd->key, fd->search_key);
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if (!cmpval) {
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e = rec;
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res = 0;
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goto done;
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}
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if (cmpval < 0)
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b = rec + 1;
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else
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e = rec - 1;
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} while (b <= e);
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if (rec != e && e >= 0) {
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len = hfs_brec_lenoff(bnode, e, &off);
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keylen = hfs_brec_keylen(bnode, e);
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2010-10-14 20:53:48 +07:00
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if (keylen == 0) {
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res = -EINVAL;
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goto fail;
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}
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2005-04-17 05:20:36 +07:00
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hfs_bnode_read(bnode, fd->key, off, keylen);
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}
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done:
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fd->record = e;
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fd->keyoffset = off;
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fd->keylength = keylen;
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fd->entryoffset = off + keylen;
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fd->entrylength = len - keylen;
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2010-10-14 20:53:48 +07:00
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fail:
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2005-04-17 05:20:36 +07:00
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return res;
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}
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/* Traverse a B*Tree from the root to a leaf finding best fit to key */
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/* Return allocated copy of node found, set recnum to best record */
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int hfs_brec_find(struct hfs_find_data *fd)
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{
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struct hfs_btree *tree;
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struct hfs_bnode *bnode;
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u32 nidx, parent;
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__be32 data;
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int height, res;
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tree = fd->tree;
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if (fd->bnode)
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hfs_bnode_put(fd->bnode);
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fd->bnode = NULL;
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nidx = tree->root;
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if (!nidx)
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return -ENOENT;
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height = tree->depth;
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res = 0;
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parent = 0;
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for (;;) {
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bnode = hfs_bnode_find(tree, nidx);
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if (IS_ERR(bnode)) {
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res = PTR_ERR(bnode);
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bnode = NULL;
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break;
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}
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if (bnode->height != height)
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goto invalid;
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if (bnode->type != (--height ? HFS_NODE_INDEX : HFS_NODE_LEAF))
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goto invalid;
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bnode->parent = parent;
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res = __hfs_brec_find(bnode, fd);
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if (!height)
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break;
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if (fd->record < 0)
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goto release;
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parent = nidx;
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hfs_bnode_read(bnode, &data, fd->entryoffset, 4);
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nidx = be32_to_cpu(data);
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hfs_bnode_put(bnode);
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}
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fd->bnode = bnode;
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return res;
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invalid:
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2006-01-19 08:43:05 +07:00
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printk(KERN_ERR "hfs: inconsistency in B*Tree (%d,%d,%d,%u,%u)\n",
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2005-04-17 05:20:36 +07:00
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height, bnode->height, bnode->type, nidx, parent);
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res = -EIO;
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release:
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hfs_bnode_put(bnode);
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return res;
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}
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int hfs_brec_read(struct hfs_find_data *fd, void *rec, int rec_len)
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{
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int res;
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res = hfs_brec_find(fd);
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if (res)
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return res;
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if (fd->entrylength > rec_len)
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return -EINVAL;
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hfs_bnode_read(fd->bnode, rec, fd->entryoffset, fd->entrylength);
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return 0;
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}
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int hfs_brec_goto(struct hfs_find_data *fd, int cnt)
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{
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struct hfs_btree *tree;
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struct hfs_bnode *bnode;
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int idx, res = 0;
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u16 off, len, keylen;
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bnode = fd->bnode;
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tree = bnode->tree;
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if (cnt < 0) {
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cnt = -cnt;
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while (cnt > fd->record) {
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cnt -= fd->record + 1;
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fd->record = bnode->num_recs - 1;
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idx = bnode->prev;
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if (!idx) {
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res = -ENOENT;
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goto out;
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}
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hfs_bnode_put(bnode);
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bnode = hfs_bnode_find(tree, idx);
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if (IS_ERR(bnode)) {
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res = PTR_ERR(bnode);
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bnode = NULL;
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goto out;
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}
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}
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fd->record -= cnt;
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} else {
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while (cnt >= bnode->num_recs - fd->record) {
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cnt -= bnode->num_recs - fd->record;
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fd->record = 0;
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idx = bnode->next;
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if (!idx) {
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res = -ENOENT;
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goto out;
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}
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hfs_bnode_put(bnode);
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bnode = hfs_bnode_find(tree, idx);
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if (IS_ERR(bnode)) {
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res = PTR_ERR(bnode);
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bnode = NULL;
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goto out;
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}
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}
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fd->record += cnt;
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}
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len = hfs_brec_lenoff(bnode, fd->record, &off);
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keylen = hfs_brec_keylen(bnode, fd->record);
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2010-10-14 20:53:48 +07:00
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if (keylen == 0) {
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res = -EINVAL;
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goto out;
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}
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2005-04-17 05:20:36 +07:00
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fd->keyoffset = off;
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fd->keylength = keylen;
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fd->entryoffset = off + keylen;
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fd->entrylength = len - keylen;
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hfs_bnode_read(bnode, fd->key, off, keylen);
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out:
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fd->bnode = bnode;
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return res;
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}
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