Example #1
0
int DfsInodeReadBytes(int handle, void *mem, int start_byte, int num_bytes) {
    int i;
    int end_byte = start_byte+num_bytes-1;
    int byte_start,byte_end;
    int block_start,block_end;
    dfs_block block;
    int blocknum;
    int byte_read;

  //  printf("In DfsInodeReadBytes\n");
    if(sb.valid == 0){
      printf("File system not open!\n");
      return DFS_FAIL;
    }
    if((handle<0)||(handle>DFS_INODE_MAX_NUM)){
      printf("Invalid inode handle = %d\n",handle);
      return DFS_FAIL;
    }
    if(inodes[handle].inuse == 0){
      printf("Inode not allocated!\n");
      return DFS_FAIL;
    } 
    if((start_byte<0)||(num_bytes<0)||((end_byte)>inodes[handle].filesize)){
      printf("Invalid start_byte = %d  or num_byte= %d\n",start_byte,num_bytes);
      return DFS_FAIL;
    }
    
    block_start = (start_byte/sb.filesys_blocksize);
    byte_start = (start_byte%sb.filesys_blocksize);
    block_end = (end_byte/sb.filesys_blocksize);
    byte_end = (end_byte%sb.filesys_blocksize);
    if(block_start == block_end){
       blocknum = DfsInodeTranslateVirtualToFilesys(handle,block_start);
   //    printf("read from block(start=end) %d\n",blocknum);
       DfsReadBlock(blocknum,&block);
       bcopy((char *)((int)&block+byte_start),(char *)mem,num_bytes);
       return (num_bytes);
     }
    else{
       blocknum = DfsInodeTranslateVirtualToFilesys(handle,block_start);
    //   printf("read from block(1st) %d\n",blocknum);
       DfsReadBlock(blocknum,&block);
       byte_read = sb.filesys_blocksize-(byte_start);
       bcopy((char *)((int)&block+byte_start),(char *)mem,byte_read);
       for(i=(block_start)+1;i<(block_end);i++){
          blocknum = DfsInodeTranslateVirtualToFilesys(handle,i);
    //      printf("read from block(middle) %d\n",blocknum);
          DfsReadBlock(blocknum,&block);
          bcopy((char *)(&block),(char *)((int)mem+byte_read),sb.filesys_blocksize);
          byte_read +=sb.filesys_blocksize;
          } 
       blocknum = DfsInodeTranslateVirtualToFilesys(handle,block_end);
    //   printf("read from block(last) %d\n",blocknum);
       DfsReadBlock(blocknum,&block);
       bcopy((char *)(&block),(char *)((int)mem+byte_read),(byte_end)+1);
       byte_read +=(byte_end)+1;
        return (byte_read);
     }
       
}
Example #2
0
int DfsOpenFileSystem() {
    disk_block diskb;
    dfs_block dfsb;
    char* inbytes;
    unsigned int i;
//Basic steps:
// Check that filesystem is not already open
    if(sb.valid) {
        printf("DfsOpenFilesystem: File system is already open\n");
        return DFS_FAIL;
    }
// Read superblock from disk.  Note this is using the disk read rather
// than the DFS read function because the DFS read requires a valid
// filesystem in memory already, and the filesystem cannot be valid
// until we read the superblock. Also, we don't know the block size
// until we read the superblock, either.
    DiskReadBlock(1, &diskb);

// Copy the data from the block we just read into the superblock in memory
    bcopy(diskb.data, (char*) &sb, sizeof(sb));
    // sb should be valid at this point since sb was supposed to be valid on disk
    if(!sb.valid) {
        printf("DfsOpenFileSystem: Filesystem on disk is not valid\n");
        return DFS_FAIL;
    }

// All other blocks are sized by virtual block size:
// Read inodes
    inbytes = (char*) inodes;
    for(i = sb.inode_start_block; i < sb.fbv_start_block; i++) {
        DfsReadBlock(i, &dfsb);
        bcopy(dfsb.data, &(inbytes[(i - sb.inode_start_block) * sb.blocksize]), sb.blocksize);
    }
// Read free block vector
    inbytes = (char*) fbv;
    for(i = sb.fbv_start_block; i < sb.data_start_block; i++) {
        DfsReadBlock(i, &dfsb);
        bcopy(dfsb.data, &(inbytes[(i - sb.fbv_start_block) * sb.blocksize]), sb.blocksize);
    }
// Change superblock to be invalid, write back to disk, then change
// it back to be valid in memory
    sb.valid = 0;
    bzero(diskb.data, DISK_BLOCKSIZE);
    bcopy((char*)&sb, diskb.data, sizeof(sb));
    DiskWriteBlock(1, &diskb);
    sb.valid = 1;
    return DFS_SUCCESS;
}
Example #3
0
int  DfsInodeAllocateVirtualBlock(int handle, int virtual_blocknum) {
     dfs_block indirect_table;
     int blocknum;
     uint32 *table;
     
   //  printf("In DfsInodeAllocateVirtualBlock\n");  
     if (sb.valid == 0){
        printf("File system not opened\n");
        return DFS_FAIL;
        }
     if((handle<0)||(handle>DFS_INODE_MAX_NUM)){
        printf("Invalid inode handle = %d\n",handle);
        return DFS_FAIL;
        }
     if(inodes[handle].inuse == 0){
        printf("Inode not allocated!\n");
        return DFS_FAIL;
        }
     if((virtual_blocknum<0)||(virtual_blocknum>(sb.filesys_blocksize/sizeof(uint32)+10))){
        printf("Invalid virtural_blocknum = %d\n",virtual_blocknum);
        return DFS_FAIL;
       }
     //check direct or indirect
     if(virtual_blocknum < 10){
       if((blocknum = DfsAllocateBlock()) == DFS_FAIL){
          printf("Cannot allocate block for direct table\n");
          return DFS_FAIL;
         }
        inodes[handle].direct[virtual_blocknum] =(uint32)blocknum;
        return blocknum;
       }
     else{
        table =(uint32 *)(&indirect_table);
        if((inodes[handle].indirect)!=0){
           DfsReadBlock(inodes[handle].indirect,(dfs_block *)table); 
          if((blocknum = DfsAllocateBlock()) == DFS_FAIL){
            printf("Cannot allocate block for direct table\n");
            return DFS_FAIL;
          }
          table[virtual_blocknum-10] =(uint32)blocknum;
          DfsWriteBlock(inodes[handle].indirect,(dfs_block *)table);
          return blocknum;
         }
         else{   
         if((blocknum = DfsAllocateBlock()) == DFS_FAIL){
            printf("Cannot allocate block for indirect table\n");
            return DFS_FAIL;
          }
          inodes[handle].indirect = (uint32)blocknum;
          bzero((char *)table,sb.filesys_blocksize); 
          if((blocknum = DfsAllocateBlock()) == DFS_FAIL){
             printf("Cannot allocate block for indirect address\n");
             return DFS_FAIL;
            }
          table[virtual_blocknum-10] = (uint32)blocknum;
          DfsWriteBlock(inodes[handle].indirect,(dfs_block *)table);
          return blocknum;
          }
      }
}
Example #4
0
int DfsInodeDelete(int handle) {
    int i;
    dfs_block indirect_table;
    uint32 *table;
  //  printf("In DfsInodeDelete\n");
    if (sb.valid == 0){
       printf("File system not open!\n");
       return DFS_FAIL;
    }
    if((handle<0)||(handle>DFS_INODE_MAX_NUM)){
       printf("Invalid inode handle = %d\n",handle);
       return DFS_FAIL;
    }
     if(inodes[handle].inuse == 0){
       printf("Inode not allocated!\n");
       return DFS_FAIL;
    }
    LockHandleAcquire(lock_inode);
    //Free direct table then check if there is indirect address
    for(i=0;i<10;i++){
      if(inodes[handle].direct[i]!=0){
      if(DfsFreeBlock((int)inodes[handle].direct[i])==DFS_FAIL){
         printf("Cannot free blocks in direct table!\n");
         return DFS_FAIL;
      }
      inodes[handle].direct[i]=0;
     }
    }
   //Free the indirect table
    if(inodes[handle].indirect != 0){
      table =(uint32 *)(&indirect_table);
      DfsReadBlock(inodes[handle].indirect,&indirect_table);
        for(i=0;i<(sb.filesys_blocksize)/sizeof(uint32);i++){
           if(table[i]!=0){
             if (DfsFreeBlock((int)table[i])== DFS_FAIL){
                 printf("Cannot free blocks in indirect table\n");
                 return DFS_FAIL;
               }
           }
        }
       if(DfsFreeBlock((int)inodes[handle].indirect)==DFS_FAIL){
          printf("Cannot free blocks in indirect table\n");
       }
       inodes[handle].indirect=0;
     }

    FreeEntry(handle);
    inodes[handle].filesize = 0;
  //  for(i=0;i< FILENAME_LENGTH;i++){
 //       inodes[handle].filename[i]='\0';
 //   }
    inodes[handle].permission = 0;
    inodes[handle].type = 0;
    inodes[handle].ownerid = 0;
    inodes[handle].inuse = 0;
    LockHandleRelease(lock_inode);
    return DFS_SUCCESS;
}
Example #5
0
//-----------------------------------------------------------------
// DfsInodeTranslateVirtualToFilesys translates the
// virtual_blocknum to the corresponding file system block using
// the inode identified by handle. Return DFS_FAIL on failure.
//-----------------------------------------------------------------
uint32 DfsInodeTranslateVirtualToFilesys(uint32 handle, uint32 virtual_blocknum) {
    dfs_block dfsb;
    int* block_entry_table;
    if(!sb.valid) {
        printf("DfsInodeTranslateVirtualToFilesys: invalid file system\n");
        return DFS_FAIL;
    }
    if(!inodes[handle].valid) {
        printf("DfsInodeTranslateVirtualToFilesys: invalid inode\n");
        return DFS_FAIL;
    }

    if(virtual_blocknum >= 10) {
        block_entry_table = (int*) dfsb.data;
        if(!DFS_IS_BLOCK_ENTRY_VALID(inodes[handle].indir_block_entry)) {
            printf("DfsInodeTranslateVirtualToFilesys: invalid block entry in indirect blocks %d\n", virtual_blocknum);
            return DFS_FAIL;
        }
        DfsReadBlock(DFS_GET_BLOCK_NUM(inodes[handle].indir_block_entry), &dfsb);
        virtual_blocknum -= 10;
        if(DFS_IS_BLOCK_ENTRY_VALID(block_entry_table[virtual_blocknum])) {
            return DFS_GET_BLOCK_NUM(block_entry_table[virtual_blocknum]);
        }
        else {
            printf("DfsInodeTranslateVirtualToFilesys: invalid block's block entry in indirect blocks %d\n", virtual_blocknum);
            return DFS_FAIL;
        }
    }
    else {
        block_entry_table = inodes[handle].direct_block_entries;
        if(DFS_IS_BLOCK_ENTRY_VALID(block_entry_table[virtual_blocknum])) {
            return DFS_GET_BLOCK_NUM(block_entry_table[virtual_blocknum]);
        }
        else {
            printf("DfsInodeTranslateVirtualToFilesys: invalid block entry in direct blocks %d\n", virtual_blocknum);
            return DFS_FAIL;
        }
    }
    printf("---THIS SHOULD NOT HAPPEN---\n");
    return DFS_FAIL;
}
Example #6
0
int DfsInodeTranslateVirtualToFilesys(int handle, int virtual_blocknum) {
       dfs_block indirect_table;
       uint32 *table;
       uint32 blocknum;

    //   printf("In DfsInodeTranslateVirtualToFilesys\n");  
       if (sb.valid == 0){
        printf("File system not opened\n");
        return DFS_FAIL;
        }
       if((handle<0)||(handle>DFS_INODE_MAX_NUM)){
        printf("Invalid inode handle = %d\n",handle);
        return DFS_FAIL;
        }
       if(inodes[handle].inuse == 0){
        printf("Inode not allocated!\n");
        return DFS_FAIL;
        }
       if((virtual_blocknum<0)||(virtual_blocknum>(sb.filesys_blocksize/sizeof(uint32)+10))){
        printf("Invalid virtural_blocknum = %d\n",virtual_blocknum);
        return DFS_FAIL;
       }
       //check direct or indirect
       if(virtual_blocknum<10){
        return (inodes[handle].direct[virtual_blocknum]);
        }
       else{
        if(inodes[handle].indirect == 0){
          printf("Indirect address table not exist!\n");
          return DFS_FAIL;
        }
        else{
          table = (uint32 *)(&indirect_table);
          DfsReadBlock(inodes[handle].indirect,&indirect_table);
          blocknum = table[virtual_blocknum-10];
          return (int)blocknum;
        }
      }
      return DFS_FAIL;
}
Example #7
0
int DfsInodeTruncateFile(uint32 handle) {
    int i;
    dfs_block dfsb;
    int* inints = (int*) dfsb.data;

    if(!sb.valid) {
        printf("DfsInodeTruncateFile: invalid file system\n");
        return DFS_FAIL;
    }
    if(!inodes[handle].valid) {
        printf("DfsInodeTruncateFile: invalid inode\n");
        return DFS_FAIL;
    }

    while(LockHandleAcquire(dfs_fbv_lock) != SYNC_SUCCESS);
    if(DFS_IS_BLOCK_ENTRY_VALID(inodes[handle].indir_block_entry)) {
        DfsReadBlock(DFS_GET_BLOCK_NUM(inodes[handle].indir_block_entry), &dfsb);
        for(i = 0; i < (sb.blocksize / sizeof(int)); i++) {
            if(DFS_IS_BLOCK_ENTRY_VALID(inints[i])) {
                SetFreeVector(DFS_GET_BLOCK_NUM(inints[i]), 1);
            }
        }
        // clear out the indirect block entry table
        bzero(dfsb.data, sb.blocksize);
        DfsWriteBlock(DFS_GET_BLOCK_NUM(inodes[handle].indir_block_entry), &dfsb);
        SetFreeVector(DFS_GET_BLOCK_NUM(inodes[handle].indir_block_entry), 1);
        inodes[handle].indir_block_entry = DFS_SET_BLOCK_ENTRY(0, 0);
    }
    for(i = 0; i < 10; i++) {
        if(DFS_IS_BLOCK_ENTRY_VALID(inodes[handle].direct_block_entries[i])) {
            SetFreeVector(DFS_GET_BLOCK_NUM(inodes[handle].direct_block_entries[i]), 1);
            inodes[handle].direct_block_entries[i] = DFS_SET_BLOCK_ENTRY(0, 0);
        }
    }
    LockHandleRelease(dfs_fbv_lock);

    inodes[handle].filesize = 0;
    return DFS_SUCCESS;
}
Example #8
0
//-----------------------------------------------------------------
// DfsInodeWriteBytes writes num_bytes from the memory pointed to 
// by mem to the file represented by the inode handle, starting at 
// virtual byte start_byte. Note that if you are only writing part 
// of a given file system block, you'll need to read that block 
// from the disk first. Return DFS_FAIL on failure and the number 
// of bytes written on success.
//-----------------------------------------------------------------
int DfsAllocateCheck(int handle,int blocknum){
    uint32 *table;
    dfs_block indirect_table;
 
    if(blocknum<10){
       if(inodes[handle].direct[blocknum]==0){
          return DFS_FAIL;
       }
    }
    else{
       if(inodes[handle].indirect==0){
         return DFS_FAIL;
        }
       else{
          table =(uint32 *)(&indirect_table);
          DfsReadBlock(inodes[handle].indirect,&indirect_table);
          if(table[blocknum-10]==0){
             return DFS_FAIL;
          }
        }
    }
    return DFS_SUCCESS;
}    
Example #9
0
//-----------------------------------------------------------------
// DfsInodeReadBytes reads num_bytes from the file represented by
// the inode handle, starting at virtual byte start_byte, copying
// the data to the address pointed to by mem. Return DFS_FAIL on
// failure, and the number of bytes read on success.
//-----------------------------------------------------------------
int DfsInodeReadBytes(uint32 handle, void *mem, int start_byte, int num_bytes) {
    int cur_byte = start_byte;
    int blocknum;
    int data_bytes;
    int byte_count = 0;
    dfs_block dfsb;
    char* mem_bytes = (char*) mem;

    if(!sb.valid) {
        printf("DfsInodeReadBytes: invalid file system\n");
        return DFS_FAIL;
    }
    if(!inodes[handle].valid) {
        printf("DfsInodeReadBytes: invalid inode\n");
        return DFS_FAIL;
    }
    while(byte_count < num_bytes) {
        blocknum = DfsInodeTranslateVirtualToFilesys(handle, cur_byte / sb.blocksize);
        if(blocknum == DFS_FAIL) {
            printf("Error: Trying to read from part of file that wasn't written already\n");
            return DFS_FAIL;
        }
        if(DfsReadBlock(blocknum, &dfsb) == DFS_FAIL) {
            printf("DfsInodeReadBytes: DfsReadBlock failed\n");
            break;
        }
        data_bytes = sb.blocksize - (cur_byte % sb.blocksize);
        if((byte_count + data_bytes) > num_bytes) {
            // remove the extra data bytes
            data_bytes = data_bytes - ((byte_count + data_bytes) - num_bytes);
        }
        bcopy(&(dfsb.data[cur_byte % sb.blocksize]), &(mem_bytes[byte_count]), data_bytes);
        byte_count += data_bytes;
        cur_byte = start_byte + byte_count;
    }
    return byte_count;
}
Example #10
0
int DfsOpenFileSystem() {
    int i;
    int num;
    dfs_block dfs_b;
    disk_block disk_b;
   
//Basic steps:
// Check that filesystem is not already open

// Read superblock from disk.  Note this is using the disk read rather 
// than the DFS read function because the DFS read requires a valid 
// filesystem in memory already, and the filesystem cannot be valid 
// until we read the superblock. Also, we don't know the block size 
// until we read the superblock, either.
 //  printf("In DfsOpenFileSystem\n");
// Copy the data from the block we just read into the superblock in memory

// All other blocks are sized by virtual block size:
// Read inodes
// Read free block vector
// Change superblock to be invalid, write back to disk, then change 
// it back to be valid in memory
  if (sb.valid == 1){
       printf("The filesystem is already open!\n");
       return DFS_FAIL;
     }

  if ((num = DiskReadBlock(1,&disk_b)) == DISK_FAIL){
       printf("Cannot read superblock from disk!\n");
       return DFS_FAIL;
     }

  bcopy((char *)(&disk_b),(char *)(&sb),sizeof(dfs_superblock));

//print superblock info from disk
/*  printf("superblock.valid %d\n",sb.valid);
  printf("superblock.filesys_blocksize %d\n",sb.filesys_blocksize);
  printf("superblock.filesys_blocknum %d\n",sb.filesys_blocknum);
  printf("superblock.filesys_inodestart %d\n",sb.filesys_inodestart);
  printf("superblock.inodenum %d\n",sb.inodenum);
  printf("superblock.filesys_fbvstart %d\n",sb.filesys_fbvstart);
  printf("superblock.filesys_datastart %d\n",sb.filesys_datastart);
*/
  for(i=sb.filesys_inodestart;i<sb.filesys_fbvstart;i++){
     if (( num = DfsReadBlock (i,&dfs_b)) == DFS_FAIL){
       printf("Cannot read inode from disk!\n");
       return DFS_FAIL;
        }
      bcopy((char *)(&dfs_b),(char *)(&inodes[(i-sb.filesys_inodestart)*(sb.filesys_blocksize)/sizeof(dfs_inode)]),sb.filesys_blocksize);
     }
   SetupRootDir();
//print inode info from disk
//  for(i=0;i<192;i++){
//     printf("inodes[%d].inuse=%d,inodes[%d].filesize=%d\n",i,inodes[i].inuse,i,inodes[i].filesize);
//     }
//

  for(i=sb.filesys_fbvstart;i<sb.filesys_datastart;i++){
     if (( num = DfsReadBlock(i, &dfs_b)) == DFS_FAIL){
           printf("Cannot read free block vector from disk!\n");
           return DFS_FAIL;
         }
     bcopy((char *)(&dfs_b),(char *)(&fbv[(i-sb.filesys_fbvstart)*(sb.filesys_blocksize)/sizeof(uint32)]),sb.filesys_blocksize);
    }

//print fbv info from disk
//  for(i=0;i<DFS_FBV_MAX_NUM;i++){
//     printf("fbv[%d]=0x%x\n",i,fbv[i]);
//     }
//

   DfsInvalidate();
   bzero((char *)(&disk_b),sizeof(disk_block));
   bcopy((char *)(&sb),(char *)(&disk_b),sizeof(dfs_superblock));
   if (DiskWriteBlock(1,&disk_b) == DISK_FAIL){
           printf("Cannot write superblock back to disk!\n");
           return DFS_FAIL;
   }
   sb.valid = 1;
 //  printf("Exit DfsOpenFileSystem\n");
   return DFS_SUCCESS;
}
Example #11
0
int DfsInodeWriteBytes(int handle, void *mem, int start_byte, int num_bytes) {
    int i;
    int end_byte = start_byte+num_bytes-1;
    int byte_start,byte_end;
    int block_start,block_end;
    dfs_block block;
    int blocknum;
    int byte_write;

  //  printf("In DfsInodeWriteBytes\n");
    if(sb.valid == 0){
      printf("File system not opened!\n");
      return DFS_FAIL;
    }
    if((handle<0)||(handle>DFS_INODE_MAX_NUM)){
      printf("Invalid inode handle = %d\n",handle);
      return DFS_FAIL;
      }
    if(inodes[handle].inuse == 0){
      printf("Inode not allocated!\n");
      return DFS_FAIL;
     } 
    if((start_byte<0)||(num_bytes<0)||((end_byte)>(sb.filesys_blocknum*sb.filesys_blocksize))){
      printf("Invalid start_byte = %d  or num_byte= %d\n",start_byte,num_bytes);
      return DFS_FAIL;
    }
    
    block_start = (start_byte/sb.filesys_blocksize);
    byte_start = (start_byte%sb.filesys_blocksize);
    block_end = (end_byte/sb.filesys_blocksize);
    byte_end = (end_byte%sb.filesys_blocksize);

    if(block_start == block_end){
        //check if the virtual block table is valid
        if(DfsAllocateCheck(handle,block_start)!= DFS_FAIL){
           blocknum = DfsInodeTranslateVirtualToFilesys(handle,block_start);
         //  printf("write to block(start=end,noalloc) %d\n",blocknum);
           DfsReadBlock(blocknum,&block);
           bcopy((char *)mem,(char *)((int)&block+byte_start),num_bytes);
           DfsWriteBlock(blocknum,&block);
           }
        else{
           if((blocknum = DfsInodeAllocateVirtualBlock(handle,block_start))== DFS_FAIL){
               printf("Cannot allocate a virtual block\n");
               return DFS_FAIL;
              }
         //  printf("write to block(start=end alloc) %d\n",blocknum);
           DfsReadBlock(blocknum,&block);
           bzero((char *)&block,sizeof(dfs_block));
           bcopy((char *)mem,(char *)((int)&block+byte_start),num_bytes);
           DfsWriteBlock(blocknum,&block);
          }
       inodes[handle].filesize+=num_bytes;
       return (num_bytes);
     }
    else{
       if(DfsAllocateCheck(handle,block_start)!=DFS_FAIL){
          blocknum = DfsInodeTranslateVirtualToFilesys(handle,block_start);
        //  printf("write to block(1st,noalloc) %d\n",blocknum);
          DfsReadBlock(blocknum,&block);
          byte_write = sb.filesys_blocksize-(byte_start);
          bcopy((char *)mem,(char *)((int)&block+byte_start),byte_write);
          DfsWriteBlock(blocknum,&block);
         }
       else{
          if((blocknum = DfsInodeAllocateVirtualBlock(handle,block_start)) == DFS_FAIL){
              printf("Cannot allocate a virtual block!\n");
              return DFS_FAIL;
            }
        //  printf("write to block(1st,alloc) %d\n",blocknum);
          DfsReadBlock(blocknum,&block);
          bzero((char *)&block,sizeof(dfs_block));
          byte_write = sb.filesys_blocksize-(byte_start);
          bcopy((char *)mem,(char *)((int)&block+byte_start),byte_write);
          DfsWriteBlock(blocknum,&block);
         }
       for(i=(block_start)+1;i<(block_end);i++){
          if((DfsAllocateCheck(handle,i)!=DFS_FAIL)){
             blocknum = DfsInodeTranslateVirtualToFilesys(handle,i);
        //     printf("noalloc  ");
          }
          else{
             if((blocknum = DfsInodeAllocateVirtualBlock(handle,i)) == DFS_FAIL){
        //      printf("Cannot allocate a virtual block!\n");
              return DFS_FAIL;
              }
             }
       //      printf("write to block(middle) %d\n",blocknum);
             bzero((char *)&block,sizeof(dfs_block));
             bcopy((char *)((int)mem+byte_write),(char *)(&block),sb.filesys_blocksize);
             DfsWriteBlock(blocknum,&block);
             byte_write +=sb.filesys_blocksize;
         } 
       if(DfsAllocateCheck(handle,block_end)!=DFS_FAIL){  
          blocknum = DfsInodeTranslateVirtualToFilesys(handle,block_end);
       //   printf("write to block(last,noalloc) %d\n",blocknum);
          DfsReadBlock(blocknum,&block);
          bcopy((char *)((int)mem+byte_write),(char *)(&block),(byte_end)+1);
          DfsWriteBlock(blocknum,&block); 
          byte_write +=(byte_end)+1;
         }
       else{
          if((blocknum = DfsInodeAllocateVirtualBlock(handle,block_end)) == DFS_FAIL){
             printf("Cannot allocate a virtual block!\n");
             return DFS_FAIL;
            }
      //    printf("write to block(last alloc) %d\n",blocknum);
          DfsReadBlock(blocknum,&block);
          bzero((char *)&block,sizeof(dfs_block));
          bcopy((char *)((int)mem+byte_write),(char *)(&block),(byte_end)+1);
          DfsWriteBlock(blocknum,&block); 
          byte_write +=(byte_end)+1;
         }
          inodes[handle].filesize+=byte_write;
          return (byte_write);
     }
}
Example #12
0
//-----------------------------------------------------------------
// DfsInodeWriteBytes writes num_bytes from the memory pointed to
// by mem to the file represented by the inode handle, starting at
// virtual byte start_byte. Note that if you are only writing part
// of a given file system block, you'll need to read that block
// from the disk first. Return DFS_FAIL on failure and the number
// of bytes written on success.
//-----------------------------------------------------------------
int DfsInodeWriteBytes(uint32 handle, void *mem, int start_byte, int num_bytes) {
    int cur_byte = start_byte;
    int blocknum;
    int data_bytes;
    int byte_count = 0;
    dfs_block dfsb;
    char* mem_bytes = (char*) mem;

    if(!sb.valid) {
        printf("DfsInodeWriteBytes: invalid file system\n");
        return DFS_FAIL;
    }
    if(!inodes[handle].valid) {
        printf("DfsInodeWriteBytes: invalid inode\n");
        return DFS_FAIL;
    }
    while(byte_count < num_bytes) {
        // allocate block first checks whether there's existing otherwise allocates
        blocknum = DfsInodeAllocateVirtualBlock(handle, cur_byte / sb.blocksize);
        data_bytes = sb.blocksize - (cur_byte % sb.blocksize);
        if(data_bytes == sb.blocksize) {
            // the start is blocksize aligned
            // check if end is not block aligned
            if((byte_count + data_bytes) > num_bytes) {
                // remove the extra data bytes
                data_bytes = data_bytes - ((byte_count + data_bytes) - num_bytes);
                // not block aligned so read whole block
                if(DfsReadBlock(blocknum, &dfsb) == DFS_FAIL) {
                    printf("DfsInodeReadBytes: DfsReadBlock failed\n");
                    break;
                }
            }
        }
        else {
            // start is not block algined
            // check if end is not block aligned
            if((byte_count + data_bytes) > num_bytes) {
                // remove the extra data bytes
                data_bytes = data_bytes - ((byte_count + data_bytes) - num_bytes);
            }
            // We need to do this any way since start is not block aligned
            if(DfsReadBlock(blocknum, &dfsb) == DFS_FAIL) {
                printf("DfsInodeWriteBytes: DfsReadBlock failed\n");
                break;
            }
        }
        bcopy(&(mem_bytes[byte_count]), &(dfsb.data[cur_byte % sb.blocksize]), data_bytes);
        if(DfsWriteBlock(blocknum, &dfsb) == DFS_FAIL) {
            printf("DfsInodeWriteBytes: DfsWriteBlock failed\n");
            break;
        }

        byte_count += data_bytes;
        cur_byte = start_byte + byte_count;
    }

    if(inodes[handle].filesize < (start_byte + byte_count)) {
        inodes[handle].filesize =  start_byte + byte_count;
    }

    return byte_count;
}
Example #13
0
uint32 DfsInodeAllocateVirtualBlock(uint32 handle, uint32 virtual_blocknum) {
    dfs_block dfsb;
    int blocknum;
    int* block_entry_table;
    if(!sb.valid) {
        printf("DfsInodeAllocateVirtualBlock: invalid file system\n");
        return DFS_FAIL;
    }
    if(!inodes[handle].valid) {
        printf("DfsInodeAllocateVirtualBlock: invalid inode\n");
        return DFS_FAIL;
    }

    if(virtual_blocknum >= 10) {
        block_entry_table = (int*) dfsb.data;
        if(!DFS_IS_BLOCK_ENTRY_VALID(inodes[handle].indir_block_entry)) {
            blocknum = DfsAllocateBlock();
            if(blocknum == DFS_FAIL) {
                printf("DfsInodeAllocateVirtualBlock: DfsAllocateBlock failed\n");
                return DFS_FAIL;
            }
            bzero(dfsb.data, sb.blocksize);
            DfsWriteBlock(blocknum, &dfsb);
            inodes[handle].indir_block_entry = DFS_SET_BLOCK_ENTRY(blocknum, 1);
        }
        DfsReadBlock(DFS_GET_BLOCK_NUM(inodes[handle].indir_block_entry), &dfsb);
        virtual_blocknum -= 10;
        // Before allocating new block
        // Extra check to make sure that there is no already valid entry here
        if(DFS_IS_BLOCK_ENTRY_VALID(block_entry_table[virtual_blocknum])) {
            return DFS_GET_BLOCK_NUM(block_entry_table[virtual_blocknum]);
        }
        else {
            blocknum = DfsAllocateBlock();
            if(blocknum == DFS_FAIL) {
                printf("DfsInodeAllocateVirtualBlock: DfsAllocateBlock failed\n");
                return DFS_FAIL;
            }
            block_entry_table[virtual_blocknum] = DFS_SET_BLOCK_ENTRY(blocknum, 1);
            DfsWriteBlock(DFS_GET_BLOCK_NUM(inodes[handle].indir_block_entry), &dfsb);
        }
        return blocknum;
    }
    else {
        block_entry_table = inodes[handle].direct_block_entries;
        // Before allocating new block
        // Extra check to make sure that there is no already valid entry here
        if(DFS_IS_BLOCK_ENTRY_VALID(block_entry_table[virtual_blocknum])) {
            return DFS_GET_BLOCK_NUM(block_entry_table[virtual_blocknum]);
        }
        else {
            blocknum = DfsAllocateBlock();
            if(blocknum == DFS_FAIL) {
                printf("DfsInodeAllocateVirtualBlock: DfsAllocateBlock failed\n");
                return DFS_FAIL;
            }
            block_entry_table[virtual_blocknum] = DFS_SET_BLOCK_ENTRY(blocknum, 1);
            return blocknum;
        }
    }
    printf("---THIS SHOULD NOT HAPPEN---\n");
    return DFS_FAIL;
}