| 1 |
1275 |
phoenix |
/*
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| 2 |
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* linux/fs/hfs/bnode.c
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*
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* Copyright (C) 1995-1997 Paul H. Hargrove
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* This file may be distributed under the terms of the GNU General Public License.
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*
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* This file contains the code to access nodes in the B-tree structure.
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*
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* "XXX" in a comment is a note to myself to consider changing something.
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*
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* In function preconditions the term "valid" applied to a pointer to
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* a structure means that the pointer is non-NULL and the structure it
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* points to has all fields initialized to consistent values.
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*
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* The code in this file initializes some structures which contain
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* pointers by calling memset(&foo, 0, sizeof(foo)).
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* This produces the desired behavior only due to the non-ANSI
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* assumption that the machine representation of NULL is all zeros.
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*/
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#include "hfs_btree.h"
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/*================ File-local variables ================*/
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/* debugging statistics */
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#if defined(DEBUG_BNODES) || defined(DEBUG_ALL)
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int bnode_count = 0;
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#endif
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/*================ Global functions ================*/
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/*
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* hfs_bnode_delete()
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*
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* Description:
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* This function is called to remove a bnode from the cache and
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* release its resources.
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* Input Variable(s):
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* struct hfs_bnode *bn: Pointer to the (struct hfs_bnode) to be
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| 40 |
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* removed from the cache.
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* Output Variable(s):
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* NONE
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* Returns:
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* void
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| 45 |
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* Preconditions:
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* 'bn' points to a "valid" (struct hfs_bnode).
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| 47 |
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* Postconditions:
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| 48 |
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* The node 'bn' is removed from the cache, its memory freed and its
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| 49 |
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* buffer (if any) released.
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| 50 |
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*/
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| 51 |
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void hfs_bnode_delete(struct hfs_bnode *bn)
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| 52 |
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{
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| 53 |
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#if defined(DEBUG_BNODES) || defined(DEBUG_ALL)
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| 54 |
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--bnode_count;
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#endif
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| 56 |
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/* join neighbors */
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| 57 |
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if (bn->next) {
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| 58 |
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bn->next->prev = bn->prev;
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}
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| 60 |
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if (bn->prev) {
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bn->prev->next = bn->next;
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| 62 |
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}
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| 63 |
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/* fix cache slot if necessary */
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if (bhash(bn->tree, bn->node) == bn) {
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bhash(bn->tree, bn->node) = bn->next;
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}
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| 67 |
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/* release resources */
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hfs_buffer_put(bn->buf); /* safe: checks for NULL argument */
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HFS_DELETE(bn);
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| 70 |
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}
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/*
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* hfs_bnode_read()
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*
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* Description:
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| 77 |
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* This function creates a (struct hfs_bnode) and, if appropriate,
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* inserts it in the cache.
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* Input Variable(s):
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* struct hfs_bnode *bnode: pointer to the new bnode.
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* struct hfs_btree *tree: pointer to the (struct hfs_btree)
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* containing the desired node
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* hfs_u32 node: the number of the desired node.
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* int sticky: the value to assign to the 'sticky' field.
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* Output Variable(s):
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* NONE
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* Returns:
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* (struct hfs_bnode *) pointing to the newly created bnode or NULL.
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* Preconditions:
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* 'bnode' points to a "valid" (struct hfs_bnode).
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* 'tree' points to a "valid" (struct hfs_btree).
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* 'node' is an existing node number in the B-tree.
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* Postconditions:
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* The following are true of 'bnode' upon return:
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* The 'magic' field is set to indicate a valid (struct hfs_bnode).
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* The 'sticky', 'tree' and 'node' fields are initialized to the
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* values of the of the corresponding arguments.
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* If the 'sticky' argument is zero then the fields 'prev' and
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* 'next' are initialized by inserting the (struct hfs_bnode) in the
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* linked list of the appropriate cache slot; otherwise they are
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| 101 |
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* initialized to NULL.
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| 102 |
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* The data is read from disk (or buffer cache) and the 'buf' field
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* points to the buffer for that data.
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* If no other processes tried to access this node while this
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* process was waiting on disk I/O (if necessary) then the
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* remaining fields are zero ('count', 'resrv', 'lock') or NULL
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* ('wqueue', 'rqueue') corresponding to no accesses.
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* If there were access attempts during I/O then they were blocked
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* until the I/O was complete, and the fields 'count', 'resrv',
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* 'lock', 'wqueue' and 'rqueue' reflect the results of unblocking
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| 111 |
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* those processes when the I/O was completed.
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| 112 |
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*/
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| 113 |
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void hfs_bnode_read(struct hfs_bnode *bnode, struct hfs_btree *tree,
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| 114 |
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hfs_u32 node, int sticky)
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{
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struct NodeDescriptor *nd;
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int block, lcv;
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hfs_u16 curr, prev, limit;
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/* Initialize the structure */
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memset(bnode, 0, sizeof(*bnode));
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bnode->magic = HFS_BNODE_MAGIC;
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bnode->tree = tree;
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bnode->node = node;
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bnode->sticky = sticky;
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hfs_init_waitqueue(&bnode->rqueue);
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hfs_init_waitqueue(&bnode->wqueue);
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| 129 |
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if (sticky == HFS_NOT_STICKY) {
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/* Insert it in the cache if appropriate */
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if ((bnode->next = bhash(tree, node))) {
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bnode->next->prev = bnode;
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}
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bhash(tree, node) = bnode;
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| 135 |
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}
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/* Make the bnode look like it is being
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| 138 |
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modified so other processes will wait for
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| 139 |
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the I/O to complete */
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| 140 |
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bnode->count = bnode->resrv = bnode->lock = 1;
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| 141 |
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| 142 |
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/* Read in the node, possibly causing a schedule()
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| 143 |
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call. If the I/O fails then emit a warning. Each
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| 144 |
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process that was waiting on the bnode (including
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| 145 |
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the current one) will notice the failure and
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| 146 |
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hfs_bnode_relse() the node. The last hfs_bnode_relse()
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| 147 |
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will call hfs_bnode_delete() and discard the bnode. */
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| 149 |
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block = hfs_extent_map(&tree->entry.u.file.data_fork, node, 0);
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if (!block) {
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hfs_warn("hfs_bnode_read: bad node number 0x%08x\n", node);
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} else if (hfs_buffer_ok(bnode->buf =
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hfs_buffer_get(tree->sys_mdb, block, 1))) {
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/* read in the NodeDescriptor */
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nd = (struct NodeDescriptor *)hfs_buffer_data(bnode->buf);
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| 156 |
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bnode->ndFLink = hfs_get_hl(nd->ndFLink);
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| 157 |
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bnode->ndBLink = hfs_get_hl(nd->ndBLink);
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| 158 |
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bnode->ndType = nd->ndType;
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| 159 |
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bnode->ndNHeight = nd->ndNHeight;
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bnode->ndNRecs = hfs_get_hs(nd->ndNRecs);
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| 161 |
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| 162 |
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/* verify the integrity of the node */
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prev = sizeof(struct NodeDescriptor);
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limit = HFS_SECTOR_SIZE - sizeof(hfs_u16)*(bnode->ndNRecs + 1);
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for (lcv=1; lcv <= (bnode->ndNRecs + 1); ++lcv) {
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curr = hfs_get_hs(RECTBL(bnode, lcv));
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| 167 |
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if ((curr < prev) || (curr > limit)) {
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| 168 |
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hfs_warn("hfs_bnode_read: corrupt node "
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| 169 |
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"number 0x%08x\n", node);
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| 170 |
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hfs_buffer_put(bnode->buf);
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| 171 |
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bnode->buf = NULL;
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| 172 |
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break;
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| 173 |
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}
|
| 174 |
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prev = curr;
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| 175 |
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}
|
| 176 |
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}
|
| 177 |
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| 178 |
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/* Undo our fakery with the lock state and
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| 179 |
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hfs_wake_up() anyone who we managed to trick */
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| 180 |
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--bnode->count;
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| 181 |
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bnode->resrv = bnode->lock = 0;
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| 182 |
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hfs_wake_up(&bnode->rqueue);
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| 183 |
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}
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| 184 |
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| 185 |
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/*
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| 186 |
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* hfs_bnode_lock()
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| 187 |
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*
|
| 188 |
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* Description:
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| 189 |
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* This function does the locking of a bnode.
|
| 190 |
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* Input Variable(s):
|
| 191 |
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* struct hfs_bnode *bn: pointer to the (struct hfs_bnode) to lock
|
| 192 |
|
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* int lock_type: the type of lock desired
|
| 193 |
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* Output Variable(s):
|
| 194 |
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* NONE
|
| 195 |
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* Returns:
|
| 196 |
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* void
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| 197 |
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* Preconditions:
|
| 198 |
|
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* 'bn' points to a "valid" (struct hfs_bnode).
|
| 199 |
|
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* 'lock_type' is a valid hfs_lock_t
|
| 200 |
|
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* Postconditions:
|
| 201 |
|
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* The 'count' field of 'bn' is incremented by one. If 'lock_type'
|
| 202 |
|
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* is HFS_LOCK_RESRV the 'resrv' field is also incremented.
|
| 203 |
|
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*/
|
| 204 |
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void hfs_bnode_lock(struct hfs_bnode_ref *bnr, int lock_type)
|
| 205 |
|
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{
|
| 206 |
|
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struct hfs_bnode *bn = bnr->bn;
|
| 207 |
|
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|
| 208 |
|
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if ((lock_type == bnr->lock_type) || !bn) {
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| 209 |
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return;
|
| 210 |
|
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}
|
| 211 |
|
|
|
| 212 |
|
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if (bnr->lock_type == HFS_LOCK_WRITE) {
|
| 213 |
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hfs_bnode_commit(bnr->bn);
|
| 214 |
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}
|
| 215 |
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|
|
| 216 |
|
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switch (lock_type) {
|
| 217 |
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default:
|
| 218 |
|
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goto bail;
|
| 219 |
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break;
|
| 220 |
|
|
|
| 221 |
|
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case HFS_LOCK_READ:
|
| 222 |
|
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/* We may not obtain read access if any process is
|
| 223 |
|
|
currently modifying or waiting to modify this node.
|
| 224 |
|
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If we can't obtain access we wait on the rqueue
|
| 225 |
|
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wait queue to be woken up by the modifying process
|
| 226 |
|
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when it relinquishes its lock. */
|
| 227 |
|
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switch (bnr->lock_type) {
|
| 228 |
|
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default:
|
| 229 |
|
|
goto bail;
|
| 230 |
|
|
break;
|
| 231 |
|
|
|
| 232 |
|
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case HFS_LOCK_NONE:
|
| 233 |
|
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while (bn->lock || waitqueue_active(&bn->wqueue)) {
|
| 234 |
|
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hfs_sleep_on(&bn->rqueue);
|
| 235 |
|
|
}
|
| 236 |
|
|
++bn->count;
|
| 237 |
|
|
break;
|
| 238 |
|
|
}
|
| 239 |
|
|
break;
|
| 240 |
|
|
|
| 241 |
|
|
case HFS_LOCK_RESRV:
|
| 242 |
|
|
/* We may not obtain a reservation (read access with
|
| 243 |
|
|
an option to write later), if any process currently
|
| 244 |
|
|
holds a reservation on this node. That includes
|
| 245 |
|
|
any process which is currently modifying this node.
|
| 246 |
|
|
If we can't obtain access, then we wait on the
|
| 247 |
|
|
rqueue wait queue to e woken up by the
|
| 248 |
|
|
reservation-holder when it calls hfs_bnode_relse. */
|
| 249 |
|
|
switch (bnr->lock_type) {
|
| 250 |
|
|
default:
|
| 251 |
|
|
goto bail;
|
| 252 |
|
|
break;
|
| 253 |
|
|
|
| 254 |
|
|
case HFS_LOCK_NONE:
|
| 255 |
|
|
while (bn->resrv) {
|
| 256 |
|
|
hfs_sleep_on(&bn->rqueue);
|
| 257 |
|
|
}
|
| 258 |
|
|
bn->resrv = 1;
|
| 259 |
|
|
++bn->count;
|
| 260 |
|
|
break;
|
| 261 |
|
|
|
| 262 |
|
|
case HFS_LOCK_WRITE:
|
| 263 |
|
|
bn->lock = 0;
|
| 264 |
|
|
hfs_wake_up(&bn->rqueue);
|
| 265 |
|
|
break;
|
| 266 |
|
|
}
|
| 267 |
|
|
break;
|
| 268 |
|
|
|
| 269 |
|
|
case HFS_LOCK_WRITE:
|
| 270 |
|
|
switch (bnr->lock_type) {
|
| 271 |
|
|
default:
|
| 272 |
|
|
goto bail;
|
| 273 |
|
|
break;
|
| 274 |
|
|
|
| 275 |
|
|
case HFS_LOCK_NONE:
|
| 276 |
|
|
while (bn->resrv) {
|
| 277 |
|
|
hfs_sleep_on(&bn->rqueue);
|
| 278 |
|
|
}
|
| 279 |
|
|
bn->resrv = 1;
|
| 280 |
|
|
++bn->count;
|
| 281 |
|
|
case HFS_LOCK_RESRV:
|
| 282 |
|
|
while (bn->count > 1) {
|
| 283 |
|
|
hfs_sleep_on(&bn->wqueue);
|
| 284 |
|
|
}
|
| 285 |
|
|
bn->lock = 1;
|
| 286 |
|
|
break;
|
| 287 |
|
|
}
|
| 288 |
|
|
break;
|
| 289 |
|
|
|
| 290 |
|
|
case HFS_LOCK_NONE:
|
| 291 |
|
|
switch (bnr->lock_type) {
|
| 292 |
|
|
default:
|
| 293 |
|
|
goto bail;
|
| 294 |
|
|
break;
|
| 295 |
|
|
|
| 296 |
|
|
case HFS_LOCK_READ:
|
| 297 |
|
|
/* This process was reading this node. If
|
| 298 |
|
|
there is now exactly one other process using
|
| 299 |
|
|
the node then hfs_wake_up() a (potentially
|
| 300 |
|
|
nonexistent) waiting process. Note that I
|
| 301 |
|
|
refer to "a" process since the reservation
|
| 302 |
|
|
system ensures that only one process can
|
| 303 |
|
|
get itself on the wait queue. */
|
| 304 |
|
|
if (bn->count == 2) {
|
| 305 |
|
|
hfs_wake_up(&bn->wqueue);
|
| 306 |
|
|
}
|
| 307 |
|
|
break;
|
| 308 |
|
|
|
| 309 |
|
|
case HFS_LOCK_WRITE:
|
| 310 |
|
|
/* This process was modifying this node.
|
| 311 |
|
|
Unlock the node and fall-through to the
|
| 312 |
|
|
HFS_LOCK_RESRV case, since a 'reservation'
|
| 313 |
|
|
is a prerequisite for HFS_LOCK_WRITE. */
|
| 314 |
|
|
bn->lock = 0;
|
| 315 |
|
|
case HFS_LOCK_RESRV:
|
| 316 |
|
|
/* This process had placed a 'reservation' on
|
| 317 |
|
|
this node, indicating an intention to
|
| 318 |
|
|
possibly modify the node. We can get to
|
| 319 |
|
|
this spot directly (if the 'reservation'
|
| 320 |
|
|
not converted to a HFS_LOCK_WRITE), or by
|
| 321 |
|
|
falling through from the above case if the
|
| 322 |
|
|
reservation was converted.
|
| 323 |
|
|
Since HFS_LOCK_RESRV and HFS_LOCK_WRITE
|
| 324 |
|
|
both block processes that want access
|
| 325 |
|
|
(HFS_LOCK_RESRV blocks other processes that
|
| 326 |
|
|
want reservations but allow HFS_LOCK_READ
|
| 327 |
|
|
accesses, while HFS_LOCK_WRITE must have
|
| 328 |
|
|
exclusive access and thus blocks both
|
| 329 |
|
|
types) we hfs_wake_up() any processes that
|
| 330 |
|
|
might be waiting for access. If multiple
|
| 331 |
|
|
processes are waiting for a reservation
|
| 332 |
|
|
then the magic of process scheduling will
|
| 333 |
|
|
settle the dispute. */
|
| 334 |
|
|
bn->resrv = 0;
|
| 335 |
|
|
hfs_wake_up(&bn->rqueue);
|
| 336 |
|
|
break;
|
| 337 |
|
|
}
|
| 338 |
|
|
--bn->count;
|
| 339 |
|
|
break;
|
| 340 |
|
|
}
|
| 341 |
|
|
bnr->lock_type = lock_type;
|
| 342 |
|
|
return;
|
| 343 |
|
|
|
| 344 |
|
|
bail:
|
| 345 |
|
|
hfs_warn("hfs_bnode_lock: invalid lock change: %d->%d.\n",
|
| 346 |
|
|
bnr->lock_type, lock_type);
|
| 347 |
|
|
return;
|
| 348 |
|
|
}
|
| 349 |
|
|
|
| 350 |
|
|
/*
|
| 351 |
|
|
* hfs_bnode_relse()
|
| 352 |
|
|
*
|
| 353 |
|
|
* Description:
|
| 354 |
|
|
* This function is called when a process is done using a bnode. If
|
| 355 |
|
|
* the proper conditions are met then we call hfs_bnode_delete() to remove
|
| 356 |
|
|
* it from the cache. If it is not deleted then we update its state
|
| 357 |
|
|
* to reflect one less process using it.
|
| 358 |
|
|
* Input Variable(s):
|
| 359 |
|
|
* struct hfs_bnode *bn: pointer to the (struct hfs_bnode) to release.
|
| 360 |
|
|
* int lock_type: The type of lock held by the process releasing this node.
|
| 361 |
|
|
* Output Variable(s):
|
| 362 |
|
|
* NONE
|
| 363 |
|
|
* Returns:
|
| 364 |
|
|
* void
|
| 365 |
|
|
* Preconditions:
|
| 366 |
|
|
* 'bn' is NULL or points to a "valid" (struct hfs_bnode).
|
| 367 |
|
|
* Postconditions:
|
| 368 |
|
|
* If 'bn' meets the appropriate conditions (see below) then it is
|
| 369 |
|
|
* kept in the cache and all fields are set to consistent values
|
| 370 |
|
|
* which reflect one less process using the node than upon entry.
|
| 371 |
|
|
* If 'bn' does not meet the conditions then it is deleted (see
|
| 372 |
|
|
* hfs_bnode_delete() for postconditions).
|
| 373 |
|
|
* In either case, if 'lock_type' is HFS_LOCK_WRITE
|
| 374 |
|
|
* then the corresponding buffer is dirtied.
|
| 375 |
|
|
*/
|
| 376 |
|
|
void hfs_bnode_relse(struct hfs_bnode_ref *bnr)
|
| 377 |
|
|
{
|
| 378 |
|
|
struct hfs_bnode *bn;
|
| 379 |
|
|
|
| 380 |
|
|
if (!bnr || !(bn = bnr->bn)) {
|
| 381 |
|
|
return;
|
| 382 |
|
|
}
|
| 383 |
|
|
|
| 384 |
|
|
/* We update the lock state of the node if it is still in use
|
| 385 |
|
|
or if it is "sticky" (such as the B-tree head and root).
|
| 386 |
|
|
Otherwise we just delete it. */
|
| 387 |
|
|
if ((bn->count > 1) || (waitqueue_active(&bn->rqueue)) || (bn->sticky != HFS_NOT_STICKY)) {
|
| 388 |
|
|
hfs_bnode_lock(bnr, HFS_LOCK_NONE);
|
| 389 |
|
|
} else {
|
| 390 |
|
|
/* dirty buffer if we (might) have modified it */
|
| 391 |
|
|
if (bnr->lock_type == HFS_LOCK_WRITE) {
|
| 392 |
|
|
hfs_bnode_commit(bn);
|
| 393 |
|
|
}
|
| 394 |
|
|
hfs_bnode_delete(bn);
|
| 395 |
|
|
bnr->lock_type = HFS_LOCK_NONE;
|
| 396 |
|
|
}
|
| 397 |
|
|
bnr->bn = NULL;
|
| 398 |
|
|
}
|
| 399 |
|
|
|
| 400 |
|
|
/*
|
| 401 |
|
|
* hfs_bnode_find()
|
| 402 |
|
|
*
|
| 403 |
|
|
* Description:
|
| 404 |
|
|
* This function is called to obtain a bnode. The cache is
|
| 405 |
|
|
* searched for the node. If it not found there it is added to
|
| 406 |
|
|
* the cache by hfs_bnode_read(). There are two special cases node=0
|
| 407 |
|
|
* (the header node) and node='tree'->bthRoot (the root node), in
|
| 408 |
|
|
* which the nodes are obtained from fields of 'tree' without
|
| 409 |
|
|
* consulting or modifying the cache.
|
| 410 |
|
|
* Input Variable(s):
|
| 411 |
|
|
* struct hfs_tree *tree: pointer to the (struct hfs_btree) from
|
| 412 |
|
|
* which to get a node.
|
| 413 |
|
|
* int node: the node number to get from 'tree'.
|
| 414 |
|
|
* int lock_type: The kind of access (HFS_LOCK_READ, or
|
| 415 |
|
|
* HFS_LOCK_RESRV) to obtain to the node
|
| 416 |
|
|
* Output Variable(s):
|
| 417 |
|
|
* NONE
|
| 418 |
|
|
* Returns:
|
| 419 |
|
|
* (struct hfs_bnode_ref) Reference to the requested node.
|
| 420 |
|
|
* Preconditions:
|
| 421 |
|
|
* 'tree' points to a "valid" (struct hfs_btree).
|
| 422 |
|
|
* Postconditions:
|
| 423 |
|
|
* If 'node' refers to a valid node in 'tree' and 'lock_type' has
|
| 424 |
|
|
* one of the values listed above and no I/O errors occur then the
|
| 425 |
|
|
* value returned refers to a valid (struct hfs_bnode) corresponding
|
| 426 |
|
|
* to the requested node with the requested access type. The node
|
| 427 |
|
|
* is also added to the cache if not previously present and not the
|
| 428 |
|
|
* root or header.
|
| 429 |
|
|
* If the conditions given above are not met, the bnode in the
|
| 430 |
|
|
* returned reference is NULL.
|
| 431 |
|
|
*/
|
| 432 |
|
|
struct hfs_bnode_ref hfs_bnode_find(struct hfs_btree *tree,
|
| 433 |
|
|
hfs_u32 node, int lock_type)
|
| 434 |
|
|
{
|
| 435 |
|
|
struct hfs_bnode *bn;
|
| 436 |
|
|
struct hfs_bnode *empty = NULL;
|
| 437 |
|
|
struct hfs_bnode_ref bnr;
|
| 438 |
|
|
|
| 439 |
|
|
bnr.lock_type = HFS_LOCK_NONE;
|
| 440 |
|
|
bnr.bn = NULL;
|
| 441 |
|
|
|
| 442 |
|
|
#if defined(DEBUG_BNODES) || defined(DEBUG_ALL)
|
| 443 |
|
|
hfs_warn("hfs_bnode_find: %c %d:%d\n",
|
| 444 |
|
|
lock_type==HFS_LOCK_READ?'R':
|
| 445 |
|
|
(lock_type==HFS_LOCK_RESRV?'V':'W'),
|
| 446 |
|
|
(int)ntohl(tree->entry.cnid), node);
|
| 447 |
|
|
#endif
|
| 448 |
|
|
|
| 449 |
|
|
/* check special cases */
|
| 450 |
|
|
if (!node) {
|
| 451 |
|
|
bn = &tree->head;
|
| 452 |
|
|
goto return_it;
|
| 453 |
|
|
} else if (node == tree->bthRoot) {
|
| 454 |
|
|
bn = tree->root;
|
| 455 |
|
|
goto return_it;
|
| 456 |
|
|
}
|
| 457 |
|
|
|
| 458 |
|
|
restart:
|
| 459 |
|
|
/* look for the node in the cache. */
|
| 460 |
|
|
bn = bhash(tree, node);
|
| 461 |
|
|
while (bn && (bn->magic == HFS_BNODE_MAGIC)) {
|
| 462 |
|
|
if (bn->node == node) {
|
| 463 |
|
|
goto found_it;
|
| 464 |
|
|
}
|
| 465 |
|
|
bn = bn->next;
|
| 466 |
|
|
}
|
| 467 |
|
|
|
| 468 |
|
|
if (!empty) {
|
| 469 |
|
|
#if defined(DEBUG_BNODES) || defined(DEBUG_ALL)
|
| 470 |
|
|
++bnode_count;
|
| 471 |
|
|
#endif
|
| 472 |
|
|
if (HFS_NEW(empty)) {
|
| 473 |
|
|
goto restart;
|
| 474 |
|
|
}
|
| 475 |
|
|
return bnr;
|
| 476 |
|
|
}
|
| 477 |
|
|
bn = empty;
|
| 478 |
|
|
hfs_bnode_read(bn, tree, node, HFS_NOT_STICKY);
|
| 479 |
|
|
goto return_it;
|
| 480 |
|
|
|
| 481 |
|
|
found_it:
|
| 482 |
|
|
/* check validity */
|
| 483 |
|
|
if (bn->magic != HFS_BNODE_MAGIC) {
|
| 484 |
|
|
/* If we find a corrupt bnode then we return
|
| 485 |
|
|
NULL. However, we don't try to remove it
|
| 486 |
|
|
from the cache or release its resources
|
| 487 |
|
|
since we have no idea what kind of trouble
|
| 488 |
|
|
we could get into that way. */
|
| 489 |
|
|
hfs_warn("hfs_bnode_find: bnode cache is corrupt.\n");
|
| 490 |
|
|
return bnr;
|
| 491 |
|
|
}
|
| 492 |
|
|
if (empty) {
|
| 493 |
|
|
#if defined(DEBUG_BNODES) || defined(DEBUG_ALL)
|
| 494 |
|
|
--bnode_count;
|
| 495 |
|
|
#endif
|
| 496 |
|
|
HFS_DELETE(empty);
|
| 497 |
|
|
}
|
| 498 |
|
|
|
| 499 |
|
|
return_it:
|
| 500 |
|
|
/* Wait our turn */
|
| 501 |
|
|
bnr.bn = bn;
|
| 502 |
|
|
hfs_bnode_lock(&bnr, lock_type);
|
| 503 |
|
|
|
| 504 |
|
|
/* Check for failure to read the node from disk */
|
| 505 |
|
|
if (!hfs_buffer_ok(bn->buf)) {
|
| 506 |
|
|
hfs_bnode_relse(&bnr);
|
| 507 |
|
|
}
|
| 508 |
|
|
|
| 509 |
|
|
#if defined(DEBUG_BNODES) || defined(DEBUG_ALL)
|
| 510 |
|
|
if (!bnr.bn) {
|
| 511 |
|
|
hfs_warn("hfs_bnode_find: failed\n");
|
| 512 |
|
|
} else {
|
| 513 |
|
|
hfs_warn("hfs_bnode_find: use %d(%d) lvl %d [%d]\n", bn->count,
|
| 514 |
|
|
bn->buf->b_count, bn->ndNHeight, bnode_count);
|
| 515 |
|
|
hfs_warn("hfs_bnode_find: blnk %u flnk %u recs %u\n",
|
| 516 |
|
|
bn->ndBLink, bn->ndFLink, bn->ndNRecs);
|
| 517 |
|
|
}
|
| 518 |
|
|
#endif
|
| 519 |
|
|
|
| 520 |
|
|
return bnr;
|
| 521 |
|
|
}
|
| 522 |
|
|
|
| 523 |
|
|
/*
|
| 524 |
|
|
* hfs_bnode_commit()
|
| 525 |
|
|
*
|
| 526 |
|
|
* Called to write a possibly dirty bnode back to disk.
|
| 527 |
|
|
*/
|
| 528 |
|
|
void hfs_bnode_commit(struct hfs_bnode *bn)
|
| 529 |
|
|
{
|
| 530 |
|
|
if (hfs_buffer_ok(bn->buf)) {
|
| 531 |
|
|
struct NodeDescriptor *nd;
|
| 532 |
|
|
nd = (struct NodeDescriptor *)hfs_buffer_data(bn->buf);
|
| 533 |
|
|
|
| 534 |
|
|
hfs_put_hl(bn->ndFLink, nd->ndFLink);
|
| 535 |
|
|
hfs_put_hl(bn->ndBLink, nd->ndBLink);
|
| 536 |
|
|
nd->ndType = bn->ndType;
|
| 537 |
|
|
nd->ndNHeight = bn->ndNHeight;
|
| 538 |
|
|
hfs_put_hs(bn->ndNRecs, nd->ndNRecs);
|
| 539 |
|
|
hfs_buffer_dirty(bn->buf);
|
| 540 |
|
|
|
| 541 |
|
|
/* increment write count */
|
| 542 |
|
|
hfs_mdb_dirty(bn->tree->sys_mdb);
|
| 543 |
|
|
}
|
| 544 |
|
|
}
|
