/*
* Remove/delete an existing file
*
* This function returns zero on success.
*/
int sfs_remove(int fd)
{
blkid frame_bid, next_frame_bid;
sfs_dirblock_t dir;
sfs_inode_frame_t frame;
int i, j;
char *tmp;
/* TODO: update dir */
sfs_read_block((char*)&dir, fdtable[fd].dir_bid);
for (i = 0; i < SFS_DB_NINODES; i++)
{
if (dir.inodes[i] == fdtable[fd].inode_bid)
{
dir.inodes[i] = 0;
}
}
// Write dir block to update inode values
sfs_write_block((char*)&dir, fdtable[fd].dir_bid);
/* TODO: free inode and all its frames */
frame_bid = fdtable[fd].inode.first_frame;
while (frame_bid != 0)
{
sfs_read_block((char*)&frame, frame_bid);
// Free all the content blocks for each frame
for (j = 0; j < SFS_FRAME_COUNT; j++)
{
tmp = (char*)malloc(BLOCK_SIZE);
memset(tmp, 0, BLOCK_SIZE);
sfs_write_block(tmp, frame.content[j]);
sfs_free_block(frame.content[j]);
free(tmp);
}
next_frame_bid = frame.next;
memset(&frame, 0, BLOCK_SIZE);
sfs_write_block((char*)&frame, frame_bid);
sfs_free_block(frame_bid);
frame_bid = next_frame_bid;
}
// Free the inode
memset((char*)&fdtable[fd].inode, 0, BLOCK_SIZE);
sfs_write_block((char*)&fdtable[fd].inode, fdtable[fd].inode_bid);
sfs_free_block(fdtable[fd].inode_bid);
/* TODO: close the file */
sfs_close(fd);
return 0;
}
/*
* Remove an existing empty directory and return 0 on success.
* If the dir does not exist or still contains files, return -1.
*/
int sfs_rmdir(char *dirname)
{
sfs_dirblock_t currentDir, prevDir, nextDir;
blkid bid, prevBlkid, nextBlkid;
/* TODO: check if the dir exists */
bid = sfs_find_dir(dirname);
if (bid != 0) {
// Directory exists
sfs_read_block((char*)¤tDir, bid);
/* TODO: check if no files */
int i;
for (i = 0; i < SFS_DB_NINODES; i++)
{
if (currentDir.inodes[i] != 0) {
// directory is not empty
printf("ERROR: inodes not empty = %d\n", currentDir.inodes[i]);
return -1;
}
}
/* TODO: go thru the linked list to delete the dir*/
// Need to change the next_dir pointer of the previous dir and dir to be deleted
nextBlkid = sb.first_dir;
if (nextBlkid == bid) {
// Deleting the root directory
sb.first_dir = 0;
sfs_read_block((char*)¤tDir, nextBlkid);
currentDir.next_dir = 0;
memset(currentDir.dir_name, 0, sizeof(currentDir.dir_name));
return 0;
}
else
{
while (nextBlkid != bid)
{
prevBlkid = nextBlkid;
sfs_read_block((char*)&prevDir, nextBlkid);
nextBlkid = prevDir.next_dir;
}
nextBlkid = currentDir.next_dir;
}
// Remove the directory: update the linked list next_dir variable
prevDir.next_dir = nextBlkid;
currentDir.next_dir = 0;
// Remove the dir_name of the dir to be deleted
memset(currentDir.dir_name, 0, sizeof(currentDir.dir_name));
// Flush the removed directory and prevDir
sfs_write_block((char*)¤tDir, bid);
sfs_write_block((char*)&prevDir, prevBlkid);
// Update the freemap so that deleted dir is empty
sfs_free_block(bid);
return 0;
}
return -1;
}
W
sfs_i_truncate (struct inode *ip, W newsize)
{
int nblock, blockno, inblock, offset, dinblock;
int i;
W errno;
W fd;
struct fs *fsp;
struct sfs_inode *sfs_ip;
fd = ip->i_device;
fsp = ip->i_fs;
sfs_ip = &(ip->i_private.sfs_inode);
nblock = ROUNDUP (newsize, fsp->fs_blksize)/fsp->fs_blksize;
if (nblock < ip->i_size_blk) {
/* 余分なブロックを開放 */
blockno = nblock;
if (blockno < SFS_DIRECT_BLOCK_ENTRY) {
/* 直接ブロックの範囲内 */
for(i = blockno; i < SFS_DIRECT_BLOCK_ENTRY; ++i) {
if (sfs_ip->sfs_i_direct[i] > 0)
sfs_free_block(fd, fsp, sfs_ip->sfs_i_direct[i]);
sfs_ip->sfs_i_direct[i] = 0;
}
sfs_free_indirect(fd, fsp, sfs_ip, 0, 0);
sfs_free_all_dindirect(fd, fsp, sfs_ip, 0);
}
else if (blockno < (SFS_DIRECT_BLOCK_ENTRY
+ (SFS_INDIRECT_BLOCK_ENTRY * SFS_INDIRECT_BLOCK))) {
/* 一重間接ブロックの範囲内 */
inblock = (blockno - SFS_DIRECT_BLOCK_ENTRY);
offset = inblock % SFS_INDIRECT_BLOCK;
inblock = inblock / SFS_INDIRECT_BLOCK;
sfs_free_indirect(fd, fsp, sfs_ip, offset, inblock);
sfs_free_all_dindirect(fd, fsp, sfs_ip, 0);
}
else if (blockno < (SFS_DIRECT_BLOCK_ENTRY
+ (SFS_INDIRECT_BLOCK_ENTRY * SFS_INDIRECT_BLOCK)
+ (SFS_DINDIRECT_BLOCK_ENTRY * SFS_INDIRECT_BLOCK * SFS_INDIRECT_BLOCK))) {
/* 二重間接ブロックの範囲内 */
blockno = blockno -
(SFS_DIRECT_BLOCK_ENTRY + SFS_INDIRECT_BLOCK_ENTRY * SFS_INDIRECT_BLOCK);
inblock = blockno / (SFS_DINDIRECT_BLOCK_ENTRY * SFS_INDIRECT_BLOCK);
dinblock = (blockno % (SFS_DINDIRECT_BLOCK_ENTRY * SFS_INDIRECT_BLOCK))
/ SFS_INDIRECT_BLOCK;
offset = blockno % SFS_INDIRECT_BLOCK;
sfs_free_dindirect(fd, fsp, sfs_ip, offset, dinblock, inblock);
sfs_free_all_dindirect(fd, fsp, sfs_ip, inblock+1);
}
}
ip->i_size = newsize;
ip->i_size_blk = nblock;
ip->i_dirty = 1;
/* これは deallocate の中で処理するのが普通 */
errno = sfs_i_sync(ip);
if (errno) {
return(errno);
}
/* ここで fs を sync する必要があるか? */
errno = sfs_syncfs(fsp);
if (errno) {
return(errno);
}
return (EP_OK);
}
/*
* Remove/delete an existing file
* This function returns zero on success.
*/
int sfs_remove(int fd_num)
{
blkid frame_bid;
sfs_dirblock_t dir;
char block_ptr[BLOCK_SIZE];
int i;
fd_struct_t fd = fdtable[fd_num];
//Set the index of the inode to zero
blkid dir_bid = fd.dir_bid;
blkid inode_bid = fd.inode_bid;
//Remove the inode from the directory
sfs_read_block(block_ptr, dir_bid);
dir = *(sfs_dirblock_t*)block_ptr;
//Find the index at which the inode is stored
int count = 0;
while(count < SFS_DB_NINODES){
if(dir.inodes[count] == inode_bid){
dir.inodes[count] = 0;
break;
}
count++;
}
dir.inodes[inode_bid] = 0;
sfs_write_block(&dir, dir_bid);
/* TODO: free inode and all its frames */
sfs_inode_t inode;
sfs_read_block(block_ptr, inode_bid);
inode = *(sfs_inode_t*)block_ptr;
char frame_ptr[BLOCK_SIZE];
sfs_inode_frame_t frame;
blkid next_frame = inode.first_frame;
//Iterate through each of the nonzero content blocks
//sfs_free_block() on all of them
while(next_frame != 0){
sfs_read_block(frame_ptr, next_frame);
frame = *(sfs_inode_frame_t*)frame_ptr;
//Check each of the entries of the frame and free nonzero blocks
int i;
for(i = 0; i < SFS_FRAME_COUNT; i++){
blkid content_blk = frame.content[i];
if(content_blk != 0){
sfs_free_block(content_blk);
}
}
sfs_free_block(next_frame);
next_frame = frame.next;
}
/* TODO: close the file */
sfs_free_block(inode_bid);
//Reset the file description to default
fd.valid = 0;
memset(&fd.inode, 0, sizeof(sfs_inode_t));
fd.dir_bid = 0;
fd.inode_bid = 0;
return 0;
}
/*
* Remove an existing empty directory and return 0 on success.
* If the dir does not exist or still contains files, return -1.
*/
int sfs_rmdir(char *dirname)
{
/* TODO: check if the dir exists */
blkid dir_bid = sfs_find_dir(dirname);
if(dir_bid == 0){
printf("ERROR sfs_rmdir: Specified directory does not exist\n");
return -1;
}
if(sb.first_dir == 0 || dir_bid == 0){
//The directory does not exist
return -1;
} else{
//Unset the corresponding bit in the freemap
sfs_free_block(dir_bid);
}
//Find the directories that come before and after the
//directory we want to delete
blkid next_dir = sb.first_dir; //First block
blkid current_dir; //Current block is sb
blkid previous_dir = 0; //No previous blocks
char block_ptr[BLOCK_SIZE];
sfs_dirblock_t dir;
if(next_dir == dir_bid){
sfs_read_block(block_ptr, next_dir);
dir = *(sfs_dirblock_t*)block_ptr;
blkid block_to_copy = dir.next_dir;
sfs_read_block(&sb, 0);
sb.first_dir = block_to_copy;
sfs_write_block(&sb, 0);
}
//General case
while(next_dir != dir_bid){
previous_dir = current_dir;
current_dir = next_dir;
sfs_read_block(block_ptr, next_dir);
dir = *(sfs_dirblock_t*)block_ptr;
next_dir = dir.next_dir;
//The next block is what we want to remove
if(next_dir == dir_bid){
//Set the next dir of the current block to the next+1 block
sfs_read_block(block_ptr, next_dir);
dir = *(sfs_dirblock_t*)block_ptr;
blkid block_to_copy = dir.next_dir;
sfs_read_block(block_ptr, current_dir);
dir = *(sfs_dirblock_t*)block_ptr;
dir.next_dir = block_to_copy;
sfs_write_block(&dir, current_dir);
}
}
return 0;
}