/**
* @brief Write data on an opened file
*
* Help from FUSE
*
* Write should return exactly the number of bytes requested except on error.
*
* @param path file path
* @param buf buffer where we have data to write
* @param size quantity of bytes to write
* @param offset offset over the writing
* @param fi FUSE structure linked to the opened file
* @return 0 on success and <0 on error
**/
static int my_write(const char *path, const char *buf, size_t size, off_t offset, struct fuse_file_info *fi) {
char buffer[BLOCK_SIZE_BYTES]; // 1 bloque de caracteres.
int bytes2Write = size, totalWrite = 0;
NodeStruct *node = myFileSystem.nodes[fi->fh]; // fh==File handle. May be filled in by filesystem in open().
fprintf(stderr, "--->>>my_write: path %s, size %zu, offset %jd, fh %"PRIu64"\n", path, size, (intmax_t)offset, fi->fh);
// Increase the file size if it is needed
if(resizeNode(fi->fh, size + offset) < 0)
return -EIO;
// Write data
while(bytes2Write) {
int i;
int currentBlock, offBloque;
currentBlock = node->blocks[offset / BLOCK_SIZE_BYTES];
offBloque = offset % BLOCK_SIZE_BYTES;
// posicionas el cursor del archivo en el bloque + offset.
// lees un bloque entero empezando en esa posición. SI alguno de los dos falla exit.
if((lseek(myFileSystem.fdVirtualDisk, currentBlock * BLOCK_SIZE_BYTES, SEEK_SET) == (off_t) - 1) ||
(read(myFileSystem.fdVirtualDisk, &buffer, BLOCK_SIZE_BYTES) == -1)) {
perror("Failed lseek/read in my_write");
return -EIO;
}
// Desde el punto inicial del offset, hasta el final del bloque, escribes la información
// del buf (texto que nos pasan en la función) en el buffer.
for(i = offBloque; (i < BLOCK_SIZE_BYTES) && (totalWrite < size); i++) {
buffer[i] = buf[totalWrite++];
}
// GUardas el buffer con la información modificada en el archivo indicado en el descriptor físico.
if((lseek(myFileSystem.fdVirtualDisk, currentBlock * BLOCK_SIZE_BYTES, SEEK_SET) == (off_t) - 1) ||
(write(myFileSystem.fdVirtualDisk, &buffer, BLOCK_SIZE_BYTES) == -1)) {
perror("Failed lseek/write in my_write");
return -EIO;
}
// Discont the written stuff
bytes2Write -= (i - offBloque);
offset += i;
}
sync();
node->modificationTime = time(NULL);
updateSuperBlock(&myFileSystem);
updateBitmap(&myFileSystem);
updateNode(&myFileSystem, fi->fh, node);
return size;
}
int my_unlink(const char *filename) {
// printDirectory(myFileSystem.directory); // DEBUG stuff only for debugging
/***** Copiar filename sin '/' en una nueva variable para
***** poder pasarla a findFileByNAme (que no admite strings constantes) ****/
int i=0;
char* fname=(char*)(filename+1); // Convert ffrom const char to char. Y también, quitar el primer character (/) sumando uno al puntero de filename (hace algoritimia de punteros.)
/** 1. Buscar si el archivo está en nuestro directorio **/
/** Si está, liberar el archivo y poner el nombre a empty **/
/** OJO! NO hay que tocar nodeIdx... **/
int nodeIndexDir = findFileByName(&myFileSystem, fname); // NodeIDx índice que ocupa un nodo en el array de nodos
if (nodeIndexDir == -1) {
fprintf(stderr, "File wasn't found on the directory entry\n");
return -1; // File is not on the directory.
}
// FILE to erase is on the directory. Free the directory entry.
myFileSystem.directory.numFiles -= 1; // Decrementar numero de archivos en el directorio.
myFileSystem.directory.files[nodeIndexDir].freeFile = true; // Put the node in directory as free.
updateDirectory(&myFileSystem);
int nodeIdx = myFileSystem.directory.files[nodeIndexDir].nodeIdx; // Hacer una copia de nodoIDx del directorio que nos sirve para acceder al array de nodos.
NodeStruct* inode=myFileSystem.nodes[nodeIdx];
/** 2. Borrar datos y liberar nodo usando el nodeIdx obtenido del directorio **/
myFileSystem.numFreeNodes += 1; // Increase the number of free nodes by 1 because e erased one.
for (i=0;i<inode->numBlocks;i++)
myFileSystem.bitMap[inode->blocks[i]] = 0; // Marcar bloques de datos en bitmap como libre
myFileSystem.superBlock.numOfFreeBlocks+=inode->numBlocks;
updateBitmap(&myFileSystem);
updateSuperBlock(&myFileSystem);
/**********************************************
* Se podría poner unicamente a NULL? Es peor?
**********************************************/
inode->numBlocks=0;
inode->fileSize=0;
inode->freeNode=true; // Delete the note from the node's array.
updateNode(&myFileSystem,nodeIdx,inode);
free(inode);
myFileSystem.nodes[nodeIdx]=NULL;
//printAllNodes(myFileSystem.nodes);
//printDirectory(myFileSystem.directory); // DEBUG stuff only for debugging
fprintf(stderr, "\n Congrats!!! %s file deleted \n", filename);
return 0;
}
/**
* @brief Modifies the data size originally reserved by an inode, reserving or removing space if needed.
*
* @param idxNode inode number
* @param newSize new size for the inode
* @return int
**/
int resizeNode(uint64_t idxNode, size_t newSize) {
NodeStruct *node = myFileSystem.nodes[idxNode];
char block[BLOCK_SIZE_BYTES];
int i, diff = newSize - node->fileSize;
if(!diff)
return 0;
memset(block, 0, sizeof(char)*BLOCK_SIZE_BYTES);
/// File size increases
if(diff > 0) {
/// Delete the extra conent of the last block if it exists and is not full
if(node->numBlocks && node->fileSize % BLOCK_SIZE_BYTES) {
int currentBlock = node->blocks[node->numBlocks - 1];
if((lseek(myFileSystem.fdVirtualDisk, currentBlock * BLOCK_SIZE_BYTES, SEEK_SET) == (off_t) - 1) ||
(read(myFileSystem.fdVirtualDisk, &block, BLOCK_SIZE_BYTES) == -1)) {
perror("Failed lseek/read in resizeNode");
return -EIO;
}
int offBlock = node->fileSize % BLOCK_SIZE_BYTES;
int bytes2Write = (diff > (BLOCK_SIZE_BYTES - offBlock)) ? BLOCK_SIZE_BYTES - offBlock : diff;
for(i = 0; i < bytes2Write; i++) {
block[offBlock++] = 0;
}
if((lseek(myFileSystem.fdVirtualDisk, currentBlock * BLOCK_SIZE_BYTES, SEEK_SET) == (off_t) - 1) ||
(write(myFileSystem.fdVirtualDisk, &block, BLOCK_SIZE_BYTES) == -1)) {
perror("Failed lseek/write in resizeNode");
return -EIO;
}
}
/// File size in blocks after the increment
int newBlocks = (newSize + BLOCK_SIZE_BYTES - 1) / BLOCK_SIZE_BYTES - node->numBlocks;
if(newBlocks) {
memset(block, 0, sizeof(char)*BLOCK_SIZE_BYTES);
// We check that there is enough space
if(newBlocks > myFileSystem.superBlock.numOfFreeBlocks)
return -ENOSPC;
myFileSystem.superBlock.numOfFreeBlocks -= newBlocks;
int currentBlock = node->numBlocks;
node->numBlocks += newBlocks;
for(i = 0; currentBlock != node->numBlocks; i++) {
if(myFileSystem.bitMap[i] == 0) {
myFileSystem.bitMap[i] = 1;
node->blocks[currentBlock] = i;
currentBlock++;
// Clean disk (necessary for truncate)
if((lseek(myFileSystem.fdVirtualDisk, i * BLOCK_SIZE_BYTES, SEEK_SET) == (off_t) - 1) ||
(write(myFileSystem.fdVirtualDisk, &block, BLOCK_SIZE_BYTES) == -1)) {
perror("Failed lseek/write in resizeNode");
return -EIO;
}
}
}
}
node->fileSize += diff;
}
/// File decreases
else {
// File size in blocks after truncation
int numBlocks = (newSize + BLOCK_SIZE_BYTES - 1) / BLOCK_SIZE_BYTES;
myFileSystem.superBlock.numOfFreeBlocks += (node->numBlocks - numBlocks);
for(i = node->numBlocks; i > numBlocks; i--) {
int nBloque = node->blocks[i - 1];
myFileSystem.bitMap[nBloque] = 0;
// Clean disk (it is not really necessary)
if((lseek(myFileSystem.fdVirtualDisk, nBloque * BLOCK_SIZE_BYTES, SEEK_SET) == (off_t) - 1) ||
(write(myFileSystem.fdVirtualDisk, &block, BLOCK_SIZE_BYTES) == -1)) {
perror("Failed lseek/write in resizeNode");
return -EIO;
}
}
node->numBlocks = numBlocks;
node->fileSize += diff;
}
node->modificationTime = time(NULL);
sync();
/// Update all the information in the backup file
updateSuperBlock(&myFileSystem);
updateBitmap(&myFileSystem);
updateNode(&myFileSystem, idxNode, node);
return 0;
}
int myMkfs(MyFileSystem *myFileSystem, int diskSize, char *backupFileName) {
// We create the virtual disk:
myFileSystem->fdVirtualDisk = open(backupFileName, O_CREAT | O_RDWR, S_IRUSR | S_IWUSR);
// Some minimal checks:
assert(sizeof(SuperBlockStruct) <= BLOCK_SIZE_BYTES);
assert(sizeof(DirectoryStruct) <= BLOCK_SIZE_BYTES);
int numBlocks = diskSize / BLOCK_SIZE_BYTES;
int minNumBlocks = 3 + MAX_BLOCKS_WITH_NODES + 1;
// 3 --> por el superbloque, el raiz y el mapa de bits.
// 1 --> porque al menos tenemos un bloque para datos.
int maxNumBlocks = NUM_BITS;
if(numBlocks < minNumBlocks) {
return -1;
}
if(numBlocks >= maxNumBlocks) {
return -2;
}
/// BITMAP
// Initialization
int i;
for(i = 0; i < NUM_BITS; i++) {
myFileSystem->bitMap[i] = 0;
}
// First three blocks will be superblock, bitmap and directory
myFileSystem->bitMap[BITMAP_IDX] = 1;
myFileSystem->bitMap[SUPERBLOCK_IDX] = 1;
myFileSystem->bitMap[DIRECTORY_IDX] = 1;
// Next MAX_BLOCKS_WITH_NODES will contain inodes
for(i = 3; i < 3 + MAX_BLOCKS_WITH_NODES; i++) {
myFileSystem->bitMap[i] = 1;
}
updateBitmap(myFileSystem);
/// DIRECTORY
// Initialization
myFileSystem->directory.numFiles = 0;
for(i = 0; i < MAX_FILES_PER_DIRECTORY; i++) {
myFileSystem->directory.files[i].freeFile = 1;
}
updateDirectory(myFileSystem);
/// INODES
NodeStruct currentNode;
currentNode.freeNode = 1;
for(i = 0; i < MAX_NODES; i++) {
updateNode(myFileSystem, i, ¤tNode);
}
/// SUPERBLOCK
initializeSuperBlock(myFileSystem, diskSize);
updateSuperBlock(myFileSystem);
sync();
// At the end we have at least one block
assert(myQuota(myFileSystem) >= 1);
if(initializeNodes(myFileSystem)){
myFree(myFileSystem);
return -3;
}
printf("SF: %s, %d B (%d B/block), %d blocks\n", backupFileName, diskSize, BLOCK_SIZE_BYTES, numBlocks);
printf("1 block for SUPERBLOCK (%u B)\n", (unsigned int)sizeof(SuperBlockStruct));
printf("1 block for BITMAP, covering %u blocks, %u B\n", (unsigned int)NUM_BITS, (unsigned int)(NUM_BITS * BLOCK_SIZE_BYTES));
printf("1 block for DIRECTORY (%u B)\n", (unsigned int)sizeof(DirectoryStruct));
printf("%d blocks for inodes (%u B/inode, %u inodes)\n", MAX_BLOCKS_WITH_NODES, (unsigned int)sizeof(NodeStruct), (unsigned int)MAX_NODES);
printf("%d blocks for data (%d B)\n", myFileSystem->superBlock.numOfFreeBlocks, BLOCK_SIZE_BYTES * myFileSystem->superBlock.numOfFreeBlocks);
printf("Formatting completed!\n");
return 0;
}