lbalance.c | Explore in Territory

/*
 * Copyright 2000 by Hans Reiser, licensing governed by reiserfs/README
 */

#include <linux/uaccess.h>
#include <linux/string.h>
#include <linux/time.h>
#include "reiserfs.h"
#include <linux/buffer_head.h>

/*
 * copy copy_count entries from source directory item to dest buffer
 * (creating new item if needed)
 */
static void leaf_copy_dir_entries(struct buffer_info *dest_bi,
				  struct buffer_head *source, int last_first,
				  int item_num, int from, int copy_count)
{ … }

/*
 * Copy the first (if last_first == FIRST_TO_LAST) or last
 * (last_first == LAST_TO_FIRST) item or part of it or nothing
 * (see the return 0 below) from SOURCE to the end (if last_first)
 * or beginning (!last_first) of the DEST
 */
/* returns 1 if anything was copied, else 0 */
static int leaf_copy_boundary_item(struct buffer_info *dest_bi,
				   struct buffer_head *src, int last_first,
				   int bytes_or_entries)
{ … }

/*
 * copy cpy_mun items from buffer src to buffer dest
 * last_first == FIRST_TO_LAST means, that we copy cpy_num items beginning
 *                             from first-th item in src to tail of dest
 * last_first == LAST_TO_FIRST means, that we copy cpy_num items beginning
 *                             from first-th item in src to head of dest
 */
static void leaf_copy_items_entirely(struct buffer_info *dest_bi,
				     struct buffer_head *src, int last_first,
				     int first, int cpy_num)
{ … }

/*
 * This function splits the (liquid) item into two items (useful when
 * shifting part of an item into another node.)
 */
static void leaf_item_bottle(struct buffer_info *dest_bi,
			     struct buffer_head *src, int last_first,
			     int item_num, int cpy_bytes)
{ … }

/*
 * If cpy_bytes equals minus one than copy cpy_num whole items from SOURCE
 * to DEST.  If cpy_bytes not equal to minus one than copy cpy_num-1 whole
 * items from SOURCE to DEST.  From last item copy cpy_num bytes for regular
 * item and cpy_num directory entries for directory item.
 */
static int leaf_copy_items(struct buffer_info *dest_bi, struct buffer_head *src,
			   int last_first, int cpy_num, int cpy_bytes)
{ … }

/*
 * there are types of coping: from S[0] to L[0], from S[0] to R[0],
 * from R[0] to L[0]. for each of these we have to define parent and
 * positions of destination and source buffers
 */
static void leaf_define_dest_src_infos(int shift_mode, struct tree_balance *tb,
				       struct buffer_info *dest_bi,
				       struct buffer_info *src_bi,
				       int *first_last,
				       struct buffer_head *Snew)
{ … }

/*
 * copy mov_num items and mov_bytes of the (mov_num-1)th item to
 * neighbor. Delete them from source
 */
int leaf_move_items(int shift_mode, struct tree_balance *tb, int mov_num,
		    int mov_bytes, struct buffer_head *Snew)
{ … }

/*
 * Shift shift_num items (and shift_bytes of last shifted item if
 * shift_bytes != -1) from S[0] to L[0] and replace the delimiting key
 */
int leaf_shift_left(struct tree_balance *tb, int shift_num, int shift_bytes)
{ … }

/* CLEANING STOPPED HERE */

/*
 * Shift shift_num (shift_bytes) items from S[0] to the right neighbor,
 * and replace the delimiting key
 */
int leaf_shift_right(struct tree_balance *tb, int shift_num, int shift_bytes)
{ … }

static void leaf_delete_items_entirely(struct buffer_info *bi,
				       int first, int del_num);
/*
 * If del_bytes == -1, starting from position 'first' delete del_num
 * items in whole in buffer CUR.
 *   If not.
 *   If last_first == 0. Starting from position 'first' delete del_num-1
 *   items in whole. Delete part of body of the first item. Part defined by
 *   del_bytes. Don't delete first item header
 *   If last_first == 1. Starting from position 'first+1' delete del_num-1
 *   items in whole. Delete part of body of the last item . Part defined by
 *   del_bytes. Don't delete last item header.
*/
void leaf_delete_items(struct buffer_info *cur_bi, int last_first,
		       int first, int del_num, int del_bytes)
{ … }

/* insert item into the leaf node in position before */
void leaf_insert_into_buf(struct buffer_info *bi, int before,
			  struct item_head * const inserted_item_ih,
			  const char * const inserted_item_body,
			  int zeros_number)
{ … }

/*
 * paste paste_size bytes to affected_item_num-th item.
 * When item is a directory, this only prepare space for new entries
 */
void leaf_paste_in_buffer(struct buffer_info *bi, int affected_item_num,
			  int pos_in_item, int paste_size,
			  const char *body, int zeros_number)
{ … }

/*
 * cuts DEL_COUNT entries beginning from FROM-th entry. Directory item
 * does not have free space, so it moves DEHs and remaining records as
 * necessary. Return value is size of removed part of directory item
 * in bytes.
 */
static int leaf_cut_entries(struct buffer_head *bh,
			    struct item_head *ih, int from, int del_count)
{ … }

/*
 * when cut item is part of regular file
 *      pos_in_item - first byte that must be cut
 *      cut_size - number of bytes to be cut beginning from pos_in_item
 *
 * when cut item is part of directory
 *      pos_in_item - number of first deleted entry
 *      cut_size - count of deleted entries
 */
void leaf_cut_from_buffer(struct buffer_info *bi, int cut_item_num,
			  int pos_in_item, int cut_size)
{ … }

/* delete del_num items from buffer starting from the first'th item */
static void leaf_delete_items_entirely(struct buffer_info *bi,
				       int first, int del_num)
{ … }

/*
 * paste new_entry_count entries (new_dehs, records) into position
 * before to item_num-th item
 */
void leaf_paste_entries(struct buffer_info *bi,
			int item_num,
			int before,
			int new_entry_count,
			struct reiserfs_de_head *new_dehs,
			const char *records, int paste_size)
{ … }
linux/fs/reiserfs/lbalance.c
