/*
* Copyright (c) 1987,1997, Prentice Hall
* All rights reserved.
*
* Redistribution and use of the MINIX operating system in source and
* binary forms, with or without modification, are permitted provided
* that the following conditions are met:
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* - Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials provided
* with the distribution.
* - Neither the name of Prentice Hall nor the names of the software
* authors or contributors may be used to endorse or promote
* products derived from this software without specific prior
* written permission.
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS, AUTHORS, AND
* CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL PRENTICE HALL OR ANY AUTHORS OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
* BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
* OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/** @addtogroup FileSystemImpl
* @{
*/
/**
* @file block.c
* @brief Basic methods for reading blocks.
*/
#include <stdio.h>
#include <async.h>
#include <sysinfo.h>
#include "fs.h"
#include "block.h"
#include "super.h"
#include "../rd/rd.h"
block_t* work_block; /**< A temporary variable for storing the working block */
/**
* Allocates memory for working block
*/
int init_block()
{
/* Allocating free space for working block. */
work_block
= (block_t
*)malloc(sizeof(block_t
));
if (work_block != NULL)
return TRUE;
return FALSE;
}
/**
* Returns requested block according its number
*/
block_t *get_block(register block_num_t block_nr)
{
if (block_nr == NO_BLOCK)
return (get_zero_block());
work_block->b_blocknr = block_nr;
read_block(work_block);
return work_block;
}
/**
* Return a block filled with zeroes
*/
block_t *get_zero_block()
{
/* Setting all bytes inside block to 0 */
memset(work_block
->b.
b__data, 0, BLOCK_SIZE
);
return work_block;
}
/**
* Process reading of requested block
*/
void read_block(register block_t *bp)
{
int r;
offset_t pos, header_size;
header_size = sysinfo_value("rd.header_size");
pos = header_size + (offset_t)bp->b_blocknr * BLOCK_SIZE;
/* Reading a block with specified number from ramdisk into shared buffer. */
r = async_req_2(rd_phone, RD_READ_BLOCK, pos, BLOCK_SIZE, NULL, NULL);
if (r < 0) {
print_console_int("Unrecoverable disk error on RAMDISK, block: %d\n", bp->b_blocknr);
print_console_int("Error number: %d\n", r);
status = FS_EIO;
return;
}
/* Copy retrieved data from buffer into work block. */
memcpy((void *)(bp
->b.
b__data), (void *)buffer
, BLOCK_SIZE
);
status = BLOCK_SIZE;
}
/**
* }
*/