bnode.c

linux 内核源代码

/*
 *  linux/fs/hfsplus/bnode.c
 *
 * Copyright (C) 2001
 * Brad Boyer ([e-mail])
 * (C) 2003 Ardis Technologies <[e-mail]>
 *
 * Handle basic btree node operations
 */

#include <linux/string.h>
#include <linux/slab.h>
#include <linux/pagemap.h>
#include <linux/fs.h>
#include <linux/swap.h>

#include "hfsplus_fs.h"
#include "hfsplus_raw.h"

/* Copy a specified range of bytes from the raw data of a node */
void hfs_bnode_read(struct hfs_bnode *node, void *buf, int off, int len)
{
	struct page **pagep;
	int l;

	off += node->page_offset;
	pagep = node->page + (off >> PAGE_CACHE_SHIFT);
	off &= ~PAGE_CACHE_MASK;

	l = min(len, (int)PAGE_CACHE_SIZE - off);
	memcpy(buf, kmap(*pagep) + off, l);
	kunmap(*pagep);

	while ((len -= l) != 0) {
		buf += l;
		l = min(len, (int)PAGE_CACHE_SIZE);
		memcpy(buf, kmap(*++pagep), l);
		kunmap(*pagep);
	}
}

u16 hfs_bnode_read_u16(struct hfs_bnode *node, int off)
{
	__be16 data;
	// optimize later...
	hfs_bnode_read(node, &data, off, 2);
	return be16_to_cpu(data);
}

u8 hfs_bnode_read_u8(struct hfs_bnode *node, int off)
{
	u8 data;
	// optimize later...
	hfs_bnode_read(node, &data, off, 1);
	return data;
}

void hfs_bnode_read_key(struct hfs_bnode *node, void *key, int off)
{
	struct hfs_btree *tree;
	int key_len;

	tree = node->tree;
	if (node->type == HFS_NODE_LEAF ||
	    tree->attributes & HFS_TREE_VARIDXKEYS)
		key_len = hfs_bnode_read_u16(node, off) + 2;
	else
		key_len = tree->max_key_len + 2;

	hfs_bnode_read(node, key, off, key_len);
}

void hfs_bnode_write(struct hfs_bnode *node, void *buf, int off, int len)
{
	struct page **pagep;
	int l;

	off += node->page_offset;
	pagep = node->page + (off >> PAGE_CACHE_SHIFT);
	off &= ~PAGE_CACHE_MASK;

	l = min(len, (int)PAGE_CACHE_SIZE - off);
	memcpy(kmap(*pagep) + off, buf, l);
	set_page_dirty(*pagep);
	kunmap(*pagep);

	while ((len -= l) != 0) {
		buf += l;
		l = min(len, (int)PAGE_CACHE_SIZE);
		memcpy(kmap(*++pagep), buf, l);
		set_page_dirty(*pagep);
		kunmap(*pagep);
	}
}

void hfs_bnode_write_u16(struct hfs_bnode *node, int off, u16 data)
{
	__be16 v = cpu_to_be16(data);
	// optimize later...
	hfs_bnode_write(node, &v, off, 2);
}

void hfs_bnode_clear(struct hfs_bnode *node, int off, int len)
{
	struct page **pagep;
	int l;

	off += node->page_offset;
	pagep = node->page + (off >> PAGE_CACHE_SHIFT);
	off &= ~PAGE_CACHE_MASK;

	l = min(len, (int)PAGE_CACHE_SIZE - off);
	memset(kmap(*pagep) + off, 0, l);
	set_page_dirty(*pagep);
	kunmap(*pagep);

	while ((len -= l) != 0) {
		l = min(len, (int)PAGE_CACHE_SIZE);
		memset(kmap(*++pagep), 0, l);
		set_page_dirty(*pagep);
		kunmap(*pagep);
	}
}

void hfs_bnode_copy(struct hfs_bnode *dst_node, int dst,
		    struct hfs_bnode *src_node, int src, int len)
{
	struct hfs_btree *tree;
	struct page **src_page, **dst_page;
	int l;

	dprint(DBG_BNODE_MOD, "copybytes: %u,%u,%u\n", dst, src, len);
	if (!len)
		return;
	tree = src_node->tree;
	src += src_node->page_offset;
	dst += dst_node->page_offset;
	src_page = src_node->page + (src >> PAGE_CACHE_SHIFT);
	src &= ~PAGE_CACHE_MASK;
	dst_page = dst_node->page + (dst >> PAGE_CACHE_SHIFT);
	dst &= ~PAGE_CACHE_MASK;

	if (src == dst) {
		l = min(len, (int)PAGE_CACHE_SIZE - src);
		memcpy(kmap(*dst_page) + src, kmap(*src_page) + src, l);
		kunmap(*src_page);
		set_page_dirty(*dst_page);
		kunmap(*dst_page);

		while ((len -= l) != 0) {
			l = min(len, (int)PAGE_CACHE_SIZE);
			memcpy(kmap(*++dst_page), kmap(*++src_page), l);
			kunmap(*src_page);
			set_page_dirty(*dst_page);
			kunmap(*dst_page);
		}
	} else {
		void *src_ptr, *dst_ptr;

		do {
			src_ptr = kmap(*src_page) + src;
			dst_ptr = kmap(*dst_page) + dst;
			if (PAGE_CACHE_SIZE - src < PAGE_CACHE_SIZE - dst) {
				l = PAGE_CACHE_SIZE - src;
				src = 0;
				dst += l;
			} else {
				l = PAGE_CACHE_SIZE - dst;
				src += l;
				dst = 0;
			}
			l = min(len, l);
			memcpy(dst_ptr, src_ptr, l);
			kunmap(*src_page);
			set_page_dirty(*dst_page);
			kunmap(*dst_page);
			if (!dst)
				dst_page++;
			else
				src_page++;
		} while ((len -= l));
	}
}

void hfs_bnode_move(struct hfs_bnode *node, int dst, int src, int len)
{
	struct page **src_page, **dst_page;
	int l;

	dprint(DBG_BNODE_MOD, "movebytes: %u,%u,%u\n", dst, src, len);
	if (!len)
		return;
	src += node->page_offset;
	dst += node->page_offset;
	if (dst > src) {
		src += len - 1;
		src_page = node->page + (src >> PAGE_CACHE_SHIFT);
		src = (src & ~PAGE_CACHE_MASK) + 1;
		dst += len - 1;
		dst_page = node->page + (dst >> PAGE_CACHE_SHIFT);
		dst = (dst & ~PAGE_CACHE_MASK) + 1;

		if (src == dst) {
			while (src < len) {
				memmove(kmap(*dst_page), kmap(*src_page), src);
				kunmap(*src_page);
				set_page_dirty(*dst_page);
				kunmap(*dst_page);
				len -= src;
				src = PAGE_CACHE_SIZE;
				src_page--;
				dst_page--;
			}
			src -= len;
			memmove(kmap(*dst_page) + src, kmap(*src_page) + src, len);
			kunmap(*src_page);
			set_page_dirty(*dst_page);
			kunmap(*dst_page);
		} else {
			void *src_ptr, *dst_ptr;

			do {
				src_ptr = kmap(*src_page) + src;
				dst_ptr = kmap(*dst_page) + dst;
				if (src < dst) {
					l = src;
					src = PAGE_CACHE_SIZE;
					dst -= l;
				} else {
					l = dst;
					src -= l;
					dst = PAGE_CACHE_SIZE;
				}
				l = min(len, l);
				memmove(dst_ptr - l, src_ptr - l, l);
				kunmap(*src_page);
				set_page_dirty(*dst_page);
				kunmap(*dst_page);
				if (dst == PAGE_CACHE_SIZE)
					dst_page--;
				else
					src_page--;
			} while ((len -= l));
		}
	} else {
		src_page = node->page + (src >> PAGE_CACHE_SHIFT);
		src &= ~PAGE_CACHE_MASK;
		dst_page = node->page + (dst >> PAGE_CACHE_SHIFT);
		dst &= ~PAGE_CACHE_MASK;

		if (src == dst) {
			l = min(len, (int)PAGE_CACHE_SIZE - src);
			memmove(kmap(*dst_page) + src, kmap(*src_page) + src, l);
			kunmap(*src_page);
			set_page_dirty(*dst_page);
			kunmap(*dst_page);

			while ((len -= l) != 0) {
				l = min(len, (int)PAGE_CACHE_SIZE);
				memmove(kmap(*++dst_page), kmap(*++src_page), l);
				kunmap(*src_page);
				set_page_dirty(*dst_page);
				kunmap(*dst_page);
			}
		} else {
			void *src_ptr, *dst_ptr;

			do {
				src_ptr = kmap(*src_page) + src;
				dst_ptr = kmap(*dst_page) + dst;
				if (PAGE_CACHE_SIZE - src < PAGE_CACHE_SIZE - dst) {
					l = PAGE_CACHE_SIZE - src;
					src = 0;
					dst += l;
				} else {
					l = PAGE_CACHE_SIZE - dst;
					src += l;
					dst = 0;
				}
				l = min(len, l);
				memmove(dst_ptr, src_ptr, l);
				kunmap(*src_page);
				set_page_dirty(*dst_page);
				kunmap(*dst_page);
				if (!dst)
					dst_page++;
				else
					src_page++;
			} while ((len -= l));
		}
	}
}

void hfs_bnode_dump(struct hfs_bnode *node)
{
	struct hfs_bnode_desc desc;
	__be32 cnid;
	int i, off, key_off;

	dprint(DBG_BNODE_MOD, "bnode: %d\n", node->this);
	hfs_bnode_read(node, &desc, 0, sizeof(desc));
	dprint(DBG_BNODE_MOD, "%d, %d, %d, %d, %d\n",
		be32_to_cpu(desc.next), be32_to_cpu(desc.prev),
		desc.type, desc.height, be16_to_cpu(desc.num_recs));

	off = node->tree->node_size - 2;
	for (i = be16_to_cpu(desc.num_recs); i >= 0; off -= 2, i--) {
		key_off = hfs_bnode_read_u16(node, off);
		dprint(DBG_BNODE_MOD, " %d", key_off);
		if (i && node->type == HFS_NODE_INDEX) {
			int tmp;

			if (node->tree->attributes & HFS_TREE_VARIDXKEYS)
				tmp = hfs_bnode_read_u16(node, key_off) + 2;
			else
				tmp = node->tree->max_key_len + 2;
			dprint(DBG_BNODE_MOD, " (%d", tmp);
			hfs_bnode_read(node, &cnid, key_off + tmp, 4);
			dprint(DBG_BNODE_MOD, ",%d)", be32_to_cpu(cnid));
		} else if (i && node->type == HFS_NODE_LEAF) {
			int tmp;