예제 #1
0
static int hfs_releasepage(struct page *page, int mask)
{
	struct inode *inode = page->mapping->host;
	struct super_block *sb = inode->i_sb;
	struct hfs_btree *tree;
	struct hfs_bnode *node;
	u32 nidx;
	int i, res = 1;

	switch (inode->i_ino) {
	case HFS_EXT_CNID:
		tree = HFS_SB(sb)->ext_tree;
		break;
	case HFS_CAT_CNID:
		tree = HFS_SB(sb)->cat_tree;
		break;
	default:
		BUG();
		return 0;
	}
	if (tree->node_size >= PAGE_CACHE_SIZE) {
		nidx = page->index >> (tree->node_size_shift - PAGE_CACHE_SHIFT);
		spin_lock(&tree->hash_lock);
		node = hfs_bnode_findhash(tree, nidx);
		if (!node)
			;
		else if (atomic_read(&node->refcnt))
			res = 0;
		if (res && node) {
			hfs_bnode_unhash(node);
			hfs_bnode_free(node);
		}
		spin_unlock(&tree->hash_lock);
	} else {
예제 #2
0
/*
 * del_root()
 *
 * Description:
 *   Delete the current root bnode.
 * Input Variable(s):
 *   struct hfs_bnode_ref *root: reference to the root bnode
 * Output Variable(s):
 *   NONE
 * Returns:
 *   int: 0 on success, error code on failure
 * Preconditions:
 *   'root' refers to the root bnode with HFS_LOCK_WRITE access.
 *   None of 'root's children are held with HFS_LOCK_WRITE access.
 * Postconditions:
 *   The current 'root' node is removed from the tree and the depth
 *    of the tree is reduced by one.
 *   If 'root' is an index node with exactly one child, then that
 *    child becomes the new root of the tree.
 *   If 'root' is an empty leaf node the tree becomes empty.
 *   Upon return access to 'root' is relinquished.
 */
static int del_root(struct hfs_bnode_ref *root)
{
	struct hfs_btree *tree = root->bn->tree;
	struct hfs_bnode_ref child;
	hfs_u32 node;

	if (root->bn->ndNRecs > 1) {
		return 0;
	} else if (root->bn->ndNRecs == 0) {
		/* tree is empty */
		tree->bthRoot = 0;
		tree->root = NULL;
		tree->bthRoot = 0;
		tree->bthFNode = 0;
		tree->bthLNode = 0;
		--tree->bthDepth;
		tree->dirt = 1;
		if (tree->bthDepth) {
			hfs_warn("hfs_bdelete: empty tree with bthDepth=%d\n",
				 tree->bthDepth);
			goto bail;
		}
		return hfs_bnode_free(root);
	} else if (root->bn->ndType == ndIndxNode) {
		/* tree is non-empty */
		node = hfs_get_hl(bkey_record(bnode_datastart(root->bn)));

		child = hfs_bnode_find(tree, node, HFS_LOCK_READ);
		if (!child.bn) {
			hfs_warn("hfs_bdelete: can't read child node.\n");
			goto bail;
		}
			
		child.bn->sticky = HFS_STICKY;
        	if (child.bn->next) {
                	child.bn->next->prev = child.bn->prev;
        	}
        	if (child.bn->prev) {
                	child.bn->prev->next = child.bn->next;
        	}
        	if (bhash(tree, child.bn->node) == child.bn) {
                	bhash(tree, child.bn->node) = child.bn->next;
        	}
		child.bn->next = NULL;
		child.bn->prev = NULL;

		tree->bthRoot = child.bn->node;
		tree->root = child.bn;

		/* re-assign bthFNode and bthLNode if the new root is
                   a leaf node. */
		if (child.bn->ndType == ndLeafNode) {
			tree->bthFNode = node;
			tree->bthLNode = node;
		}
		hfs_bnode_relse(&child);

		tree->bthRoot = node;
		--tree->bthDepth;
		tree->dirt = 1;
		if (!tree->bthDepth) {
			hfs_warn("hfs_bdelete: non-empty tree with "
				 "bthDepth == 0\n");
			goto bail;
		}
		return hfs_bnode_free(root);	/* marks tree dirty */
	}
	hfs_bnode_relse(root);
	return 0;

bail:
	hfs_bnode_relse(root);
	return -EIO;
}
예제 #3
0
/*
 * bdelete()
 *
 * Delete the given record from a B-tree.
 */
static int bdelete(struct hfs_brec *brec)
{
	struct hfs_btree *tree = brec->tree;
	struct hfs_belem *belem = brec->bottom;
	struct hfs_belem *parent = (belem-1);
	struct hfs_bnode *bnode;
	hfs_u32 left_node, right_node;
	struct hfs_bnode_ref left, right;
	int left_space, right_space, min_space;
	int fix_right_key;
	int fix_key;
	
	while ((belem > brec->top) &&
	       (belem->flags & (HFS_BPATH_UNDERFLOW | HFS_BPATH_FIRST))) {
		bnode = belem->bnr.bn;
		fix_key = belem->flags & HFS_BPATH_FIRST;
		fix_right_key = 0;

		bdelete_nonempty(brec, belem);

		if (bnode->node == tree->root->node) {
			del_root(&belem->bnr);
			--brec->bottom;
			goto done;
		}

		/* check for btree corruption which could lead to deadlock */
		left_node = bnode->ndBLink;
		right_node = bnode->ndFLink;
		if ((left_node && hfs_bnode_in_brec(left_node, brec)) ||
		    (right_node && hfs_bnode_in_brec(right_node, brec)) ||
		    (left_node == right_node)) {
			hfs_warn("hfs_bdelete: corrupt btree\n");
			hfs_brec_relse(brec, NULL);
			return -EIO;
		}

		/* grab the left neighbor if it exists */
		if (left_node) {
			hfs_bnode_lock(&belem->bnr, HFS_LOCK_RESRV);
			left = hfs_bnode_find(tree,left_node,HFS_LOCK_WRITE);
			if (!left.bn) {
				hfs_warn("hfs_bdelete: unable to read left "
					 "neighbor.\n");
				hfs_brec_relse(brec, NULL);
				return -EIO;
			}
			hfs_bnode_lock(&belem->bnr, HFS_LOCK_WRITE);
			if (parent->record != 1) {
				left_space = bnode_freespace(left.bn);
			} else {
				left_space = NO_SPACE;
			}
		} else {
			left.bn = NULL;
			left_space = NO_SPACE;
		}

		/* grab the right neighbor if it exists */
		if (right_node) {
			right = hfs_bnode_find(tree,right_node,HFS_LOCK_WRITE);
			if (!right.bn) {
				hfs_warn("hfs_bdelete: unable to read right "
					 "neighbor.\n");
				hfs_bnode_relse(&left);
				hfs_brec_relse(brec, NULL);
				return -EIO;
			}
			if (parent->record < parent->bnr.bn->ndNRecs) {
				right_space = bnode_freespace(right.bn);
			} else {
				right_space = NO_SPACE;
			}
		} else {
			right.bn = NULL;
			right_space = NO_SPACE;
		}

		if (left_space < right_space) {
			min_space = left_space;
		} else {
			min_space = right_space;
		}

		if (min_space == NO_SPACE) {
			hfs_warn("hfs_bdelete: no siblings?\n");
			hfs_brec_relse(brec, NULL);
			return -EIO;
		}

		if (bnode->ndNRecs == 0) {
			delete_empty_bnode(left_node, &left, &belem->bnr,
					   right_node, &right);
		} else if (min_space + bnode_freespace(bnode) >= FULL) {
			if ((right_space == NO_SPACE) ||
			    ((right_space == min_space) &&
			     (left_space != NO_SPACE))) {
				hfs_bnode_shift_left(left.bn, bnode,
						     bnode->ndNRecs);
			} else {
				hfs_bnode_shift_right(bnode, right.bn, 1);
				fix_right_key = 1;
			}
			delete_empty_bnode(left_node, &left, &belem->bnr,
					   right_node, &right);
		} else if (min_space == right_space) {
			balance(bnode, right.bn);
			fix_right_key = 1;
		} else {
			balance(left.bn, bnode);
			fix_key = 1;
		}

		if (fix_right_key) {
			hfs_bnode_update_key(brec, belem, right.bn, 1);
		}

		hfs_bnode_relse(&left);
		hfs_bnode_relse(&right);

		if (bnode->ndNRecs) {
			if (fix_key) {
				hfs_bnode_update_key(brec, belem, bnode, 0);
			}
			goto done;
		}

		hfs_bnode_free(&belem->bnr);
		--brec->bottom;
		belem = parent;
		--parent;
	}

	if (belem < brec->top) {
		hfs_warn("hfs_bdelete: Missing parent.\n");
		hfs_brec_relse(brec, NULL);
		return -EIO;
	}

	bdelete_nonempty(brec, belem);

done:
	hfs_brec_relse(brec, NULL);
	return 0;
}