////////////////////////////////////////////////////////////////////////////////
//
// Function : seek_if_i_must
// Description : determines whether to seek or not
//
// Author : Nicholas Krzenski
// Last Modified : October 8, 2013
//
void seek_if_i_must(SMSA_DRUM_ID drum, SMSA_BLOCK_ID block) {
/* Are we there? */
// Incorrect drum
if( drum != curDrum) {
// Seek drum
smsa_client_operation( SEEK_DRUM, NULL);
// Update head
curDrum = drum;
curBlock = 0;
logMessage( LOG_INFO_LEVEL, "Seeking drum at [%d]\n", drum );
}
// Incorrect block
if(block != curBlock) {
// Seek block
smsa_client_operation( SEEK_BLOCK, NULL);
// Update head
curBlock = block;
logMessage( LOG_INFO_LEVEL, "Seeking block at [%d]\n", block );
}
}
int smsa_vunmount( void ) {
uint32_t command; //holds the generated "unmount" command.
ERROR_SOURCE err = 0; //holds return values of function calls to checkForErrors
if ( DEBUG )
printCache( cache_hits, disk_reads);
//save the contents of the memory to a file, so that
//it can be restored when mount is called again, rather
//than setting it to all zeros. If an error occurs in this
//function we will not return a 1 since it is not a catastrophic
//error, and the virtual memory will still function properly
//once mount is called
// err = saveDiskToFile();
//generate the op command so that we can use it to call
//the smsa_operation function to unmount the disk. Once
//again, DONT_CARE is defined as 0. After function call
//command will contain the value neccessary to call
//smsa_operation in order to unmount the disk
err = generateOPCommand ( &command, SMSA_UNMOUNT, DONT_CARE, DONT_CARE, DONT_CARE );
if ( DEBUG )
logMessage ( LOG_INFO_LEVEL, "Sending UNMOUNT Command Across the Network");
//call function with the "mount" op command,
//and NULL set as the parameter for the char*,
//since we will not use this char* in the mount
//function
if ( smsa_client_operation ( command, NULL ) ) {
logMessage ( LOG_INFO_LEVEL, "_smsa_vunmount:Failed to send UNMOUNT command on the network");
return 1;
logMessage ( LOG_INFO_LEVEL, "Successfully Unmounted the Disk" );
//free cache
if ( smsa_close_cache() )
logMessage ( LOG_INFO_LEVEL, "_smsa_vunmount:Failed to properly close cache in smsa_close_cache()" );
return 1;
}
//if checkForErrors finds that err is non-zero, it will return 1.
//see smsa_driver.h for error enum definition
return ( checkForErrors ( err, "_vumount", DONT_CARE, DONT_CARE, DONT_CARE, DONT_CARE,
DONT_CARE, DONT_CARE, DONT_CARE, DONT_CARE ) );
}
int smsa_vunmount( void ) {
// Free cache
smsa_close_cache();
// Begin unmounting, log an error is unsucessful
logMessage( LOG_INFO_LEVEL, "Unmounting...\n" );
if( smsa_client_operation( UNMOUNT_DISK, NULL ) == -1 ) {
logMessage( LOG_ERROR_LEVEL, "Unmounting disk failed...aborting\n" );
return -1;
}
logMessage( LOG_INFO_LEVEL, "Unmounted successfully!\n" );
return 0;
}
int smsa_vmount( int lines ) {
// Initialize cache
smsa_init_cache(lines);
logMessage( LOG_INFO_LEVEL, "Mounting...\n" );
if( smsa_client_operation( MOUNT_DISK, NULL ) == -1 ) {
logMessage( LOG_ERROR_LEVEL, "Mounting disk failed...aborting\n" );
return -1;
}
logMessage( LOG_INFO_LEVEL, "Mounted successfully!\n" );
// Initialize global read head
curDrum = 0;
curBlock = 0;
return 0;
}
////////////////////////////////////////////////////////////////////////////////
//
// Function : smsa_vmount
// Description : Mount the SMSA disk array virtual address space
//
// Inputs : none
// Outputs : -1 if failure or 0 if successful
int smsa_vmount( int cache_size ) {
uint32_t command; //holds the generated op command
ERROR_SOURCE err = 0; //holds return values of function calls to checkForErrors
//generate the op command, so that we can use this
//command to call the smsa_operation function to mount
//the disk. DONT_CARE is defined as 0. After function call,
//command will have the value needed to call the smsa_operation
//function
err = generateOPCommand( &command, SMSA_MOUNT, DONT_CARE, DONT_CARE, DONT_CARE );
if ( DEBUG )
logMessage ( LOG_INFO_LEVEL, "Calling smsa_client_operation to mount the Disk" );
//send the mound command with NULL set as
//the parameter for the char* since, we will
//not have to use it.
if ( smsa_client_operation( command, NULL ) ) {
logMessage ( LOG_INFO_LEVEL, "_smsa_vmount:smsa_client_operation failed when given the Mount command" );
return 1;
}
logMessage ( LOG_INFO_LEVEL, "Disk successfully Mounted. Connection established with server" );
//initialize cache
if ( smsa_init_cache ( cache_size ) ) {
logMessage ( LOG_INFO_LEVEL, "_smsa_vmount:Failed to succesfully initialize the cache" );
return 1;
}
//Initialize the drum and block head positions to zero
head.drum = 0;
head.block = 0;
if ( DEBUG )
logMessage ( LOG_INFO_LEVEL, "Block and Drum Head Structure Initalized Drum Head To %d and Block Head To %d", head.drum, head.block );
//restore the memory that was saved in the txt file,
//when vunmount finished. This will load the all disk
//and blocks with the contents of the file. If this function
//fails, we will not return 1 here and cause the program
//to fail, because being unable to load the memory from
//the file is not a catastrophic error
// err = restoreDiskFromFile();
//initialize cache performance variables
cache_hits = 0;
disk_reads = 0;
//if checkForErrors finds that err is non-zero, it will return 1.
//see smsa_driver.h for error enum definition
return ( checkForErrors ( err, "_vmount", DONT_CARE, DONT_CARE, DONT_CARE, DONT_CARE,
DONT_CARE, DONT_CARE, DONT_CARE, DONT_CARE ) );
}
int smsa_vwrite( SMSA_VIRTUAL_ADDRESS addr, uint32_t len, unsigned char *buf ) {
// First check if the length is 0
// Write nothing and return if so
if(len == 0) {
return 0;
}
/* Initialize variables */
int i;
int err = 0;
int read_bytes = 0;
uint32_t offset;
SMSA_DRUM_ID drum;
SMSA_BLOCK_ID block;
SMSA_BLOCK_ID block_orig;
unsigned char *smsa_vwrite_buffer = NULL;
drum = find_drum(addr);
block = find_block(addr);
block_orig = block;
offset = addr & 0xff;
seek_if_i_must(drum, block);
// Loop to iterate through blocks
do {
/* Bounds Check */
// Check if drum is in bounds
if( (drum > SMSA_DISK_ARRAY_SIZE) || (drum < 0) ) {
logMessage( LOG_ERROR_LEVEL, "The drum is out of bounds [%d]\n", drum );
return -1;
}
// Check if block is in bounds
if( (block > SMSA_MAX_BLOCK_ID) || (block < 0) ) {
logMessage( LOG_ERROR_LEVEL, "The block is out of bounds [%d]\n", block );
return -1;
}
// Check if original block
if( block == block_orig ) {
i = offset;
} else { i = 0; }
// If last block
if( (block == SMSA_BLOCK_SIZE) ) {
block = 0;
curBlock = 0;
drum++;
seek_if_i_must(drum, block);
}
/* Is it in the cache? */
logMessage(LOG_INFO_LEVEL, "Asking cache at: drum[%d]\tblock[%d]\n", drum, block);
smsa_vwrite_buffer = smsa_get_cache_line(drum, block);
// If Yes
if(smsa_vwrite_buffer != NULL) {
do {
smsa_vwrite_buffer[i] = buf[read_bytes];
read_bytes++;
i++;
} while( (i<SMSA_BLOCK_SIZE) && (read_bytes<len) );
block++;
curBlock++;
/* smsa_operation( SEEK_BLOCK, NULL ); */
}
// If No
else {
smsa_vwrite_buffer = (unsigned char *) malloc(SMSA_BLOCK_SIZE * sizeof(unsigned char));
// Read from disk
smsa_client_operation( DISK_READ, smsa_vwrite_buffer);
// Loop to write into buffer
do {
smsa_vwrite_buffer[i] = buf[read_bytes];
read_bytes++;
i++;
} while( (i<SMSA_BLOCK_SIZE) && (read_bytes<len) );
// Put into cache
logMessage(LOG_INFO_LEVEL, "Finding a place to put the cache entry...\n");
err = smsa_put_cache_line(drum, block, smsa_vwrite_buffer);
block++;
curBlock++;
}
if(err) {
logMessage(LOG_ERROR_LEVEL, "Something bad happened in the cache :/\n");
return -1;
}
// Write to disk
smsa_client_operation( SEEK_PREVIOUS_BLOCK, NULL );
smsa_client_operation( DISK_WRITE, smsa_vwrite_buffer );
} while(read_bytes<len);
return 0;
}
int smsa_vread( SMSA_VIRTUAL_ADDRESS addr, uint32_t len, unsigned char *buf ) {
/* First check if the length is 0 */
// Write nothing and return if so
if(len == 0) {
return 0;
}
/* Initialize variables */
int i = 0;
int err = 0;
int read_bytes = 0;
uint32_t offset;
SMSA_DRUM_ID drum;
SMSA_BLOCK_ID block;
SMSA_BLOCK_ID block_orig;
unsigned char *smsa_vread_buffer = NULL;
drum = find_drum(addr);
block = find_block(addr);
block_orig = block;
offset = addr & 0xff;
seek_if_i_must(drum, block);
// Loop to iterate through blocks
do {
/* Bounds checking */
// Check if drum is in bounds
if( (drum > SMSA_DISK_ARRAY_SIZE) || (drum < 0) ) {
logMessage( LOG_ERROR_LEVEL, "The drum is out of bounds [%d]\n", drum );
return -1;
}
// Check if block is in bounds
if( (block > SMSA_MAX_BLOCK_ID) || (block < 0) ) {
logMessage( LOG_ERROR_LEVEL, "The block is out of bounds [%d]\n", block );
return -1;
}
/* Is it the original block? */
// Yes - begin reading from offset
// No - begin reading from beginning
if( block == block_orig ) {
i = offset;
} else { i = 0; }
/* Is it last block in the drum? */
if( block == SMSA_BLOCK_SIZE) {
// Seek to the beginning of next drum
block=0;
curBlock = 0;
drum++;
seek_if_i_must(drum, block);
}
/* Is it in the cache? */
logMessage(LOG_INFO_LEVEL, "Asking cache at: drum[%d]\tblock[%d]\n", drum, block);
smsa_vread_buffer = smsa_get_cache_line(drum, block);
// If yes
if(smsa_vread_buffer != NULL) {
// Read into buf
do {
buf[read_bytes] = smsa_vread_buffer[i];
read_bytes++;
i++;
} while( (i<SMSA_BLOCK_SIZE) && (read_bytes<len) );
// seek next block
block++;
curBlock++;
smsa_client_operation( SEEK_BLOCK, NULL );
}
// If no
else {
// Allocate temp buffer
smsa_vread_buffer = (unsigned char *) malloc(SMSA_BLOCK_SIZE * sizeof(unsigned char));
// Read from disk
smsa_client_operation( DISK_READ, smsa_vread_buffer );
// Put into buf bit by bit
do {
buf[read_bytes] = smsa_vread_buffer[i];
read_bytes++;
i++;
} while( (i<SMSA_BLOCK_SIZE) && (read_bytes<len) );
// Add temp buffer into cache line
logMessage(LOG_INFO_LEVEL, "Finding a place to put the cache entry...\n");
err = smsa_put_cache_line(drum, block, smsa_vread_buffer);
block++;
curBlock++;
}
if(err) {
logMessage(LOG_ERROR_LEVEL, "Something bad happened in the cache :/\n");
return -1;
}
} while(read_bytes<len);
return 0;
}
