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 {
/*
* 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;
}
/*
* 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;
}
