| 1 |
1275 |
phoenix |
/*
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| 2 |
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* linux/fs/hfs/bdelete.c
|
| 3 |
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*
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| 4 |
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* Copyright (C) 1995-1997 Paul H. Hargrove
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| 5 |
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* This file may be distributed under the terms of the GNU General Public License.
|
| 6 |
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*
|
| 7 |
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* This file contains the code to delete records in a B-tree.
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| 8 |
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*
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| 9 |
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* "XXX" in a comment is a note to myself to consider changing something.
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| 10 |
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*
|
| 11 |
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* In function preconditions the term "valid" applied to a pointer to
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| 12 |
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* a structure means that the pointer is non-NULL and the structure it
|
| 13 |
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* points to has all fields initialized to consistent values.
|
| 14 |
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*/
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| 15 |
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| 16 |
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#include "hfs_btree.h"
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| 17 |
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|
| 18 |
|
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/*================ Variable-like macros ================*/
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| 19 |
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| 20 |
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#define FULL (HFS_SECTOR_SIZE - sizeof(struct NodeDescriptor))
|
| 21 |
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#define NO_SPACE (HFS_SECTOR_SIZE+1)
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| 22 |
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| 23 |
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/*================ File-local functions ================*/
|
| 24 |
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| 25 |
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/*
|
| 26 |
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* bdelete_nonempty()
|
| 27 |
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*
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| 28 |
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* Description:
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| 29 |
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* Deletes a record from a given bnode without regard to it becoming empty.
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| 30 |
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* Input Variable(s):
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| 31 |
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* struct hfs_brec* brec: pointer to the brec for the deletion
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| 32 |
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* struct hfs_belem* belem: which node in 'brec' to delete from
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| 33 |
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* Output Variable(s):
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| 34 |
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* NONE
|
| 35 |
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* Returns:
|
| 36 |
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* void
|
| 37 |
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* Preconditions:
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| 38 |
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* 'brec' points to a valid (struct hfs_brec).
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| 39 |
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* 'belem' points to a valid (struct hfs_belem) in 'brec'.
|
| 40 |
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* Postconditions:
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| 41 |
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* The record has been inserted in the position indicated by 'brec'.
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| 42 |
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*/
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| 43 |
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static void bdelete_nonempty(struct hfs_brec *brec, struct hfs_belem *belem)
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| 44 |
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{
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| 45 |
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int i, rec, nrecs, tomove;
|
| 46 |
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hfs_u16 size;
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| 47 |
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hfs_u8 *start;
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| 48 |
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struct hfs_bnode *bnode = belem->bnr.bn;
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| 49 |
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| 50 |
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rec = belem->record;
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| 51 |
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nrecs = bnode->ndNRecs;
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| 52 |
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size = bnode_rsize(bnode, rec);
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| 53 |
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tomove = bnode_offset(bnode, nrecs+1) - bnode_offset(bnode, rec+1);
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| 54 |
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| 55 |
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/* adjust the record table */
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| 56 |
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for (i = rec+1; i <= nrecs; ++i) {
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| 57 |
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hfs_put_hs(bnode_offset(bnode,i+1) - size, RECTBL(bnode,i));
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| 58 |
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}
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| 59 |
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| 60 |
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/* move it down */
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| 61 |
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start = bnode_key(bnode, rec);
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| 62 |
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memmove(start, start + size, tomove);
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| 63 |
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| 64 |
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/* update record count */
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| 65 |
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--bnode->ndNRecs;
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| 66 |
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}
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| 67 |
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| 68 |
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/*
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| 69 |
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* del_root()
|
| 70 |
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*
|
| 71 |
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* Description:
|
| 72 |
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* Delete the current root bnode.
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| 73 |
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* Input Variable(s):
|
| 74 |
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* struct hfs_bnode_ref *root: reference to the root bnode
|
| 75 |
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* Output Variable(s):
|
| 76 |
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* NONE
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| 77 |
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* Returns:
|
| 78 |
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* int: 0 on success, error code on failure
|
| 79 |
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* Preconditions:
|
| 80 |
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* 'root' refers to the root bnode with HFS_LOCK_WRITE access.
|
| 81 |
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* None of 'root's children are held with HFS_LOCK_WRITE access.
|
| 82 |
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* Postconditions:
|
| 83 |
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* The current 'root' node is removed from the tree and the depth
|
| 84 |
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* of the tree is reduced by one.
|
| 85 |
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* If 'root' is an index node with exactly one child, then that
|
| 86 |
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* child becomes the new root of the tree.
|
| 87 |
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* If 'root' is an empty leaf node the tree becomes empty.
|
| 88 |
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* Upon return access to 'root' is relinquished.
|
| 89 |
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*/
|
| 90 |
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static int del_root(struct hfs_bnode_ref *root)
|
| 91 |
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{
|
| 92 |
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struct hfs_btree *tree = root->bn->tree;
|
| 93 |
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struct hfs_bnode_ref child;
|
| 94 |
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hfs_u32 node;
|
| 95 |
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|
| 96 |
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if (root->bn->ndNRecs > 1) {
|
| 97 |
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return 0;
|
| 98 |
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} else if (root->bn->ndNRecs == 0) {
|
| 99 |
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/* tree is empty */
|
| 100 |
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tree->bthRoot = 0;
|
| 101 |
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tree->root = NULL;
|
| 102 |
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tree->bthRoot = 0;
|
| 103 |
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tree->bthFNode = 0;
|
| 104 |
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tree->bthLNode = 0;
|
| 105 |
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--tree->bthDepth;
|
| 106 |
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tree->dirt = 1;
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| 107 |
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if (tree->bthDepth) {
|
| 108 |
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hfs_warn("hfs_bdelete: empty tree with bthDepth=%d\n",
|
| 109 |
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tree->bthDepth);
|
| 110 |
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goto bail;
|
| 111 |
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}
|
| 112 |
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return hfs_bnode_free(root);
|
| 113 |
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} else if (root->bn->ndType == ndIndxNode) {
|
| 114 |
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/* tree is non-empty */
|
| 115 |
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node = hfs_get_hl(bkey_record(bnode_datastart(root->bn)));
|
| 116 |
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|
| 117 |
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child = hfs_bnode_find(tree, node, HFS_LOCK_READ);
|
| 118 |
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if (!child.bn) {
|
| 119 |
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hfs_warn("hfs_bdelete: can't read child node.\n");
|
| 120 |
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goto bail;
|
| 121 |
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}
|
| 122 |
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|
| 123 |
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child.bn->sticky = HFS_STICKY;
|
| 124 |
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if (child.bn->next) {
|
| 125 |
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child.bn->next->prev = child.bn->prev;
|
| 126 |
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}
|
| 127 |
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if (child.bn->prev) {
|
| 128 |
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child.bn->prev->next = child.bn->next;
|
| 129 |
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}
|
| 130 |
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if (bhash(tree, child.bn->node) == child.bn) {
|
| 131 |
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bhash(tree, child.bn->node) = child.bn->next;
|
| 132 |
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}
|
| 133 |
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child.bn->next = NULL;
|
| 134 |
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child.bn->prev = NULL;
|
| 135 |
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|
| 136 |
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tree->bthRoot = child.bn->node;
|
| 137 |
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tree->root = child.bn;
|
| 138 |
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|
| 139 |
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/* re-assign bthFNode and bthLNode if the new root is
|
| 140 |
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a leaf node. */
|
| 141 |
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if (child.bn->ndType == ndLeafNode) {
|
| 142 |
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tree->bthFNode = node;
|
| 143 |
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tree->bthLNode = node;
|
| 144 |
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}
|
| 145 |
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hfs_bnode_relse(&child);
|
| 146 |
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|
| 147 |
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tree->bthRoot = node;
|
| 148 |
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--tree->bthDepth;
|
| 149 |
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tree->dirt = 1;
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| 150 |
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if (!tree->bthDepth) {
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| 151 |
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hfs_warn("hfs_bdelete: non-empty tree with "
|
| 152 |
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"bthDepth == 0\n");
|
| 153 |
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goto bail;
|
| 154 |
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}
|
| 155 |
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return hfs_bnode_free(root); /* marks tree dirty */
|
| 156 |
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}
|
| 157 |
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hfs_bnode_relse(root);
|
| 158 |
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return 0;
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| 159 |
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| 160 |
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bail:
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| 161 |
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hfs_bnode_relse(root);
|
| 162 |
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return -EIO;
|
| 163 |
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}
|
| 164 |
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| 165 |
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| 166 |
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/*
|
| 167 |
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* delete_empty_bnode()
|
| 168 |
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*
|
| 169 |
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* Description:
|
| 170 |
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* Removes an empty non-root bnode from between 'left' and 'right'
|
| 171 |
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* Input Variable(s):
|
| 172 |
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* hfs_u32 left_node: node number of 'left' or zero if 'left' is invalid
|
| 173 |
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* struct hfs_bnode_ref *left: reference to the left neighbor of the
|
| 174 |
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* bnode to remove, or invalid if no such neighbor exists.
|
| 175 |
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* struct hfs_bnode_ref *center: reference to the bnode to remove
|
| 176 |
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* hfs_u32 right_node: node number of 'right' or zero if 'right' is invalid
|
| 177 |
|
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* struct hfs_bnode_ref *right: reference to the right neighbor of the
|
| 178 |
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* bnode to remove, or invalid if no such neighbor exists.
|
| 179 |
|
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* Output Variable(s):
|
| 180 |
|
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* NONE
|
| 181 |
|
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* Returns:
|
| 182 |
|
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* void
|
| 183 |
|
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* Preconditions:
|
| 184 |
|
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* 'left_node' is as described above.
|
| 185 |
|
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* 'left' points to a valid (struct hfs_bnode_ref) having HFS_LOCK_WRITE
|
| 186 |
|
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* access and referring to the left neighbor of 'center' if such a
|
| 187 |
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* neighbor exists, or invalid if no such neighbor exists.
|
| 188 |
|
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* 'center' points to a valid (struct hfs_bnode_ref) having HFS_LOCK_WRITE
|
| 189 |
|
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* access and referring to the bnode to delete.
|
| 190 |
|
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* 'right_node' is as described above.
|
| 191 |
|
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* 'right' points to a valid (struct hfs_bnode_ref) having HFS_LOCK_WRITE
|
| 192 |
|
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* access and referring to the right neighbor of 'center' if such a
|
| 193 |
|
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* neighbor exists, or invalid if no such neighbor exists.
|
| 194 |
|
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* Postconditions:
|
| 195 |
|
|
* If 'left' is valid its 'ndFLink' field becomes 'right_node'.
|
| 196 |
|
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* If 'right' is valid its 'ndBLink' field becomes 'left_node'.
|
| 197 |
|
|
* If 'center' was the first leaf node then the tree's 'bthFNode'
|
| 198 |
|
|
* field becomes 'right_node'
|
| 199 |
|
|
* If 'center' was the last leaf node then the tree's 'bthLNode'
|
| 200 |
|
|
* field becomes 'left_node'
|
| 201 |
|
|
* 'center' is NOT freed and access to the nodes is NOT relinquished.
|
| 202 |
|
|
*/
|
| 203 |
|
|
static void delete_empty_bnode(hfs_u32 left_node, struct hfs_bnode_ref *left,
|
| 204 |
|
|
struct hfs_bnode_ref *center,
|
| 205 |
|
|
hfs_u32 right_node, struct hfs_bnode_ref *right)
|
| 206 |
|
|
{
|
| 207 |
|
|
struct hfs_bnode *bnode = center->bn;
|
| 208 |
|
|
|
| 209 |
|
|
if (left_node) {
|
| 210 |
|
|
left->bn->ndFLink = right_node;
|
| 211 |
|
|
} else if (bnode->ndType == ndLeafNode) {
|
| 212 |
|
|
bnode->tree->bthFNode = right_node;
|
| 213 |
|
|
bnode->tree->dirt = 1;
|
| 214 |
|
|
}
|
| 215 |
|
|
|
| 216 |
|
|
if (right_node) {
|
| 217 |
|
|
right->bn->ndBLink = left_node;
|
| 218 |
|
|
} else if (bnode->ndType == ndLeafNode) {
|
| 219 |
|
|
bnode->tree->bthLNode = left_node;
|
| 220 |
|
|
bnode->tree->dirt = 1;
|
| 221 |
|
|
}
|
| 222 |
|
|
}
|
| 223 |
|
|
|
| 224 |
|
|
/*
|
| 225 |
|
|
* balance()
|
| 226 |
|
|
*
|
| 227 |
|
|
* Description:
|
| 228 |
|
|
* Attempt to equalize space usage in neighboring bnodes.
|
| 229 |
|
|
* Input Variable(s):
|
| 230 |
|
|
* struct hfs_bnode *left: the left bnode.
|
| 231 |
|
|
* struct hfs_bnode *right: the right bnode.
|
| 232 |
|
|
* Output Variable(s):
|
| 233 |
|
|
* NONE
|
| 234 |
|
|
* Returns:
|
| 235 |
|
|
* void
|
| 236 |
|
|
* Preconditions:
|
| 237 |
|
|
* 'left' and 'right' point to valid (struct hfs_bnode)s obtained
|
| 238 |
|
|
* with HFS_LOCK_WRITE access, and are neighbors.
|
| 239 |
|
|
* Postconditions:
|
| 240 |
|
|
* Records are shifted either left or right to make the space usage
|
| 241 |
|
|
* nearly equal. When exact equality is not possible the break
|
| 242 |
|
|
* point is chosen to reduce data movement.
|
| 243 |
|
|
* The key corresponding to 'right' in its parent is NOT updated.
|
| 244 |
|
|
*/
|
| 245 |
|
|
static void balance(struct hfs_bnode *left, struct hfs_bnode *right)
|
| 246 |
|
|
{
|
| 247 |
|
|
int index, left_free, right_free, half;
|
| 248 |
|
|
|
| 249 |
|
|
left_free = bnode_freespace(left);
|
| 250 |
|
|
right_free = bnode_freespace(right);
|
| 251 |
|
|
half = (left_free + right_free)/2;
|
| 252 |
|
|
|
| 253 |
|
|
if (left_free < right_free) {
|
| 254 |
|
|
/* shift right to balance */
|
| 255 |
|
|
index = left->ndNRecs + 1;
|
| 256 |
|
|
while (right_free >= half) {
|
| 257 |
|
|
--index;
|
| 258 |
|
|
right_free -= bnode_rsize(left,index)+sizeof(hfs_u16);
|
| 259 |
|
|
}
|
| 260 |
|
|
if (index < left->ndNRecs) {
|
| 261 |
|
|
#if defined(DEBUG_ALL) || defined(DEBUG_BALANCE)
|
| 262 |
|
|
hfs_warn("shifting %d of %d recs right to balance: ",
|
| 263 |
|
|
left->ndNRecs - index, left->ndNRecs);
|
| 264 |
|
|
#endif
|
| 265 |
|
|
hfs_bnode_shift_right(left, right, index+1);
|
| 266 |
|
|
#if defined(DEBUG_ALL) || defined(DEBUG_BALANCE)
|
| 267 |
|
|
hfs_warn("%d,%d\n", left->ndNRecs, right->ndNRecs);
|
| 268 |
|
|
#endif
|
| 269 |
|
|
}
|
| 270 |
|
|
} else {
|
| 271 |
|
|
/* shift left to balance */
|
| 272 |
|
|
index = 0;
|
| 273 |
|
|
while (left_free >= half) {
|
| 274 |
|
|
++index;
|
| 275 |
|
|
left_free -= bnode_rsize(right,index)+sizeof(hfs_u16);
|
| 276 |
|
|
}
|
| 277 |
|
|
if (index > 1) {
|
| 278 |
|
|
#if defined(DEBUG_ALL) || defined(DEBUG_BALANCE)
|
| 279 |
|
|
hfs_warn("shifting %d of %d recs left to balance: ",
|
| 280 |
|
|
index-1, right->ndNRecs);
|
| 281 |
|
|
#endif
|
| 282 |
|
|
hfs_bnode_shift_left(left, right, index-1);
|
| 283 |
|
|
#if defined(DEBUG_ALL) || defined(DEBUG_BALANCE)
|
| 284 |
|
|
hfs_warn("%d,%d\n", left->ndNRecs, right->ndNRecs);
|
| 285 |
|
|
#endif
|
| 286 |
|
|
}
|
| 287 |
|
|
}
|
| 288 |
|
|
}
|
| 289 |
|
|
|
| 290 |
|
|
/*
|
| 291 |
|
|
* bdelete()
|
| 292 |
|
|
*
|
| 293 |
|
|
* Delete the given record from a B-tree.
|
| 294 |
|
|
*/
|
| 295 |
|
|
static int bdelete(struct hfs_brec *brec)
|
| 296 |
|
|
{
|
| 297 |
|
|
struct hfs_btree *tree = brec->tree;
|
| 298 |
|
|
struct hfs_belem *belem = brec->bottom;
|
| 299 |
|
|
struct hfs_belem *parent = (belem-1);
|
| 300 |
|
|
struct hfs_bnode *bnode;
|
| 301 |
|
|
hfs_u32 left_node, right_node;
|
| 302 |
|
|
struct hfs_bnode_ref left, right;
|
| 303 |
|
|
int left_space, right_space, min_space;
|
| 304 |
|
|
int fix_right_key;
|
| 305 |
|
|
int fix_key;
|
| 306 |
|
|
|
| 307 |
|
|
while ((belem > brec->top) &&
|
| 308 |
|
|
(belem->flags & (HFS_BPATH_UNDERFLOW | HFS_BPATH_FIRST))) {
|
| 309 |
|
|
bnode = belem->bnr.bn;
|
| 310 |
|
|
fix_key = belem->flags & HFS_BPATH_FIRST;
|
| 311 |
|
|
fix_right_key = 0;
|
| 312 |
|
|
|
| 313 |
|
|
bdelete_nonempty(brec, belem);
|
| 314 |
|
|
|
| 315 |
|
|
if (bnode->node == tree->root->node) {
|
| 316 |
|
|
del_root(&belem->bnr);
|
| 317 |
|
|
--brec->bottom;
|
| 318 |
|
|
goto done;
|
| 319 |
|
|
}
|
| 320 |
|
|
|
| 321 |
|
|
/* check for btree corruption which could lead to deadlock */
|
| 322 |
|
|
left_node = bnode->ndBLink;
|
| 323 |
|
|
right_node = bnode->ndFLink;
|
| 324 |
|
|
if ((left_node && hfs_bnode_in_brec(left_node, brec)) ||
|
| 325 |
|
|
(right_node && hfs_bnode_in_brec(right_node, brec)) ||
|
| 326 |
|
|
(left_node == right_node)) {
|
| 327 |
|
|
hfs_warn("hfs_bdelete: corrupt btree\n");
|
| 328 |
|
|
hfs_brec_relse(brec, NULL);
|
| 329 |
|
|
return -EIO;
|
| 330 |
|
|
}
|
| 331 |
|
|
|
| 332 |
|
|
/* grab the left neighbor if it exists */
|
| 333 |
|
|
if (left_node) {
|
| 334 |
|
|
hfs_bnode_lock(&belem->bnr, HFS_LOCK_RESRV);
|
| 335 |
|
|
left = hfs_bnode_find(tree,left_node,HFS_LOCK_WRITE);
|
| 336 |
|
|
if (!left.bn) {
|
| 337 |
|
|
hfs_warn("hfs_bdelete: unable to read left "
|
| 338 |
|
|
"neighbor.\n");
|
| 339 |
|
|
hfs_brec_relse(brec, NULL);
|
| 340 |
|
|
return -EIO;
|
| 341 |
|
|
}
|
| 342 |
|
|
hfs_bnode_lock(&belem->bnr, HFS_LOCK_WRITE);
|
| 343 |
|
|
if (parent->record != 1) {
|
| 344 |
|
|
left_space = bnode_freespace(left.bn);
|
| 345 |
|
|
} else {
|
| 346 |
|
|
left_space = NO_SPACE;
|
| 347 |
|
|
}
|
| 348 |
|
|
} else {
|
| 349 |
|
|
left.bn = NULL;
|
| 350 |
|
|
left_space = NO_SPACE;
|
| 351 |
|
|
}
|
| 352 |
|
|
|
| 353 |
|
|
/* grab the right neighbor if it exists */
|
| 354 |
|
|
if (right_node) {
|
| 355 |
|
|
right = hfs_bnode_find(tree,right_node,HFS_LOCK_WRITE);
|
| 356 |
|
|
if (!right.bn) {
|
| 357 |
|
|
hfs_warn("hfs_bdelete: unable to read right "
|
| 358 |
|
|
"neighbor.\n");
|
| 359 |
|
|
hfs_bnode_relse(&left);
|
| 360 |
|
|
hfs_brec_relse(brec, NULL);
|
| 361 |
|
|
return -EIO;
|
| 362 |
|
|
}
|
| 363 |
|
|
if (parent->record < parent->bnr.bn->ndNRecs) {
|
| 364 |
|
|
right_space = bnode_freespace(right.bn);
|
| 365 |
|
|
} else {
|
| 366 |
|
|
right_space = NO_SPACE;
|
| 367 |
|
|
}
|
| 368 |
|
|
} else {
|
| 369 |
|
|
right.bn = NULL;
|
| 370 |
|
|
right_space = NO_SPACE;
|
| 371 |
|
|
}
|
| 372 |
|
|
|
| 373 |
|
|
if (left_space < right_space) {
|
| 374 |
|
|
min_space = left_space;
|
| 375 |
|
|
} else {
|
| 376 |
|
|
min_space = right_space;
|
| 377 |
|
|
}
|
| 378 |
|
|
|
| 379 |
|
|
if (min_space == NO_SPACE) {
|
| 380 |
|
|
hfs_warn("hfs_bdelete: no siblings?\n");
|
| 381 |
|
|
hfs_brec_relse(brec, NULL);
|
| 382 |
|
|
return -EIO;
|
| 383 |
|
|
}
|
| 384 |
|
|
|
| 385 |
|
|
if (bnode->ndNRecs == 0) {
|
| 386 |
|
|
delete_empty_bnode(left_node, &left, &belem->bnr,
|
| 387 |
|
|
right_node, &right);
|
| 388 |
|
|
} else if (min_space + bnode_freespace(bnode) >= FULL) {
|
| 389 |
|
|
if ((right_space == NO_SPACE) ||
|
| 390 |
|
|
((right_space == min_space) &&
|
| 391 |
|
|
(left_space != NO_SPACE))) {
|
| 392 |
|
|
hfs_bnode_shift_left(left.bn, bnode,
|
| 393 |
|
|
bnode->ndNRecs);
|
| 394 |
|
|
} else {
|
| 395 |
|
|
hfs_bnode_shift_right(bnode, right.bn, 1);
|
| 396 |
|
|
fix_right_key = 1;
|
| 397 |
|
|
}
|
| 398 |
|
|
delete_empty_bnode(left_node, &left, &belem->bnr,
|
| 399 |
|
|
right_node, &right);
|
| 400 |
|
|
} else if (min_space == right_space) {
|
| 401 |
|
|
balance(bnode, right.bn);
|
| 402 |
|
|
fix_right_key = 1;
|
| 403 |
|
|
} else {
|
| 404 |
|
|
balance(left.bn, bnode);
|
| 405 |
|
|
fix_key = 1;
|
| 406 |
|
|
}
|
| 407 |
|
|
|
| 408 |
|
|
if (fix_right_key) {
|
| 409 |
|
|
hfs_bnode_update_key(brec, belem, right.bn, 1);
|
| 410 |
|
|
}
|
| 411 |
|
|
|
| 412 |
|
|
hfs_bnode_relse(&left);
|
| 413 |
|
|
hfs_bnode_relse(&right);
|
| 414 |
|
|
|
| 415 |
|
|
if (bnode->ndNRecs) {
|
| 416 |
|
|
if (fix_key) {
|
| 417 |
|
|
hfs_bnode_update_key(brec, belem, bnode, 0);
|
| 418 |
|
|
}
|
| 419 |
|
|
goto done;
|
| 420 |
|
|
}
|
| 421 |
|
|
|
| 422 |
|
|
hfs_bnode_free(&belem->bnr);
|
| 423 |
|
|
--brec->bottom;
|
| 424 |
|
|
belem = parent;
|
| 425 |
|
|
--parent;
|
| 426 |
|
|
}
|
| 427 |
|
|
|
| 428 |
|
|
if (belem < brec->top) {
|
| 429 |
|
|
hfs_warn("hfs_bdelete: Missing parent.\n");
|
| 430 |
|
|
hfs_brec_relse(brec, NULL);
|
| 431 |
|
|
return -EIO;
|
| 432 |
|
|
}
|
| 433 |
|
|
|
| 434 |
|
|
bdelete_nonempty(brec, belem);
|
| 435 |
|
|
|
| 436 |
|
|
done:
|
| 437 |
|
|
hfs_brec_relse(brec, NULL);
|
| 438 |
|
|
return 0;
|
| 439 |
|
|
}
|
| 440 |
|
|
|
| 441 |
|
|
/*================ Global functions ================*/
|
| 442 |
|
|
|
| 443 |
|
|
/*
|
| 444 |
|
|
* hfs_bdelete()
|
| 445 |
|
|
*
|
| 446 |
|
|
* Delete the requested record from a B-tree.
|
| 447 |
|
|
*/
|
| 448 |
|
|
int hfs_bdelete(struct hfs_btree *tree, const struct hfs_bkey *key)
|
| 449 |
|
|
{
|
| 450 |
|
|
struct hfs_belem *belem;
|
| 451 |
|
|
struct hfs_bnode *bnode;
|
| 452 |
|
|
struct hfs_brec brec;
|
| 453 |
|
|
int retval;
|
| 454 |
|
|
|
| 455 |
|
|
if (!tree || (tree->magic != HFS_BTREE_MAGIC) || !key) {
|
| 456 |
|
|
hfs_warn("hfs_bdelete: invalid arguments.\n");
|
| 457 |
|
|
return -EINVAL;
|
| 458 |
|
|
}
|
| 459 |
|
|
|
| 460 |
|
|
retval = hfs_bfind(&brec, tree, key, HFS_BFIND_DELETE);
|
| 461 |
|
|
if (!retval) {
|
| 462 |
|
|
belem = brec.bottom;
|
| 463 |
|
|
bnode = belem->bnr.bn;
|
| 464 |
|
|
|
| 465 |
|
|
belem->flags = 0;
|
| 466 |
|
|
if ((bnode->ndNRecs * sizeof(hfs_u16) + bnode_end(bnode) -
|
| 467 |
|
|
bnode_rsize(bnode, belem->record)) < FULL/2) {
|
| 468 |
|
|
belem->flags |= HFS_BPATH_UNDERFLOW;
|
| 469 |
|
|
}
|
| 470 |
|
|
if (belem->record == 1) {
|
| 471 |
|
|
belem->flags |= HFS_BPATH_FIRST;
|
| 472 |
|
|
}
|
| 473 |
|
|
|
| 474 |
|
|
if (!belem->flags) {
|
| 475 |
|
|
hfs_brec_lock(&brec, brec.bottom);
|
| 476 |
|
|
} else {
|
| 477 |
|
|
hfs_brec_lock(&brec, NULL);
|
| 478 |
|
|
}
|
| 479 |
|
|
|
| 480 |
|
|
retval = bdelete(&brec);
|
| 481 |
|
|
if (!retval) {
|
| 482 |
|
|
--brec.tree->bthNRecs;
|
| 483 |
|
|
brec.tree->dirt = 1;
|
| 484 |
|
|
}
|
| 485 |
|
|
hfs_brec_relse(&brec, NULL);
|
| 486 |
|
|
}
|
| 487 |
|
|
return retval;
|
| 488 |
|
|
}
|
