CSC3150 Assignment 4 Solution

In Assignment 4, you are required to implement a mechanism of file system management via GPU's memory.
Background:
• File systems provide efficient and convenient access to the disk by allowing data to be stored, located, and retrieved easily.
• A file system poses two quite different design problems. The first problem is defining how the file system should look to the user. This task involves defining a file with its attributes, the operations allowed on a file, and the directory structure for organizing files.
• The second problem is creating algorithms and data structures to map the logical file system on to the physical secondary-storage devices.
• The file-organization module knows about files and their logical blocks, as well as physical blocks. By knowing the type of file allocation used and the location of the file, the file-organization module can translate logical block address to physical block address for the basic file system to transfer.
• Each file’s logical blocks are numbered from 0 (or 1) through N. Since the physical blocks containing the data usually do not match the logical numbers, a translation is required to locate each block.
• The logical file system manages metadata information.
• Metadata includes all of the file-system structure except the actual data (or contents of the files).
• The file-organization module also includes the free-space manager, which tracks unallocated blocks and provides these blocks to the fileorganization module when requested.
• The logical file system manages the directory structure to provide the file-organization module with the information the latter needs, given a symbolic file name. It maintains file structure via file-control blocks.
• A file-control block (FCB) (an inode in UNIX file systems) contains information about the file, including ownership, permissions, and location of the file contents.
• Because there have no OS in GPU to maintain the mechanism of the logical file system, we can try to implement a simple file system in CUDA GPU with single thread, and limit global memory as volume.
The GPU File System we need to design:
• We take the global memory as a volume (logical drive) from a hard disk.
• No directory structure stored in volume, only one root directory, no subdirectory in this file system.
• A set of file operations should be implemented.
• In this project, we use only one of GPU memory, the global memory as a volume. We don’t create the shared memory as physical memory for any data structures stored in, like system-wide open file table in memory.
• In this simple file system, we just directly take the information from a volume (in global memory) by single thread.

Specification:
• The size of volume is 1085440 bytes (1060KB).
• The size of files total is 1048576 bytes (1024KB).
• The maximum number of file is 1024.
• The maximum size of a file is 1024 bytes (1KB).
• The maximum size of a file name is 20 bytes.
• File name end with “”.
• FCB size is 32 bytes.
• FCB entries is 32KB/ 32 bytes = 1024.
• Storage block size is 32 bytes.
• fs_open:
 Open a file
 Give a file pointer to find the file’s location.
 Space in the file system must be found for the file.
 An entry for the new file must be made in the directory.
 Also accept access-mode information: read/write
 When to use write mode, if no such file name can be found, create a new zero byte file.
 Return a write/read pointer. Function definition:

 Demo usage:

• fs_write:
 To write a file.
 There is a write pointer to identify the location in the file.
 If the file has existed, cleanup the older contents of the file and write the new contents.
 Take the input buffer to write bytes data to the file. Function definition:

 Demo usage:

• fs_read:
 To read contents from a file.
 There is a read pointer to identify the location in the file.
 To read bytes data from the file to the output buffer.
 The offset of the opened file associated with the read pointer is 0 (always read the file from head). Function definition:

 Demo usage:

• fs_gsys (RM):
 To delete a file and release the file space.
 Search the directory for the named file.
 Implement gsys() to pass the RM command. Function definition.

 Demo usage

• fs_gsys (LS_D / LS_S):
 List information about files.
 Implement gsys() to pass the LS_D/LS_S commands.
 LS_D list all files name in the directory and order by modified time of files.
 LS_S list all files name and size in the directory and order by size.
 If there are several files with the same size, then first create first print.
 Function definition

 Demo usage

 Demo output

Template structure:
• The storage size of the file system is already pre-defined as:

• At first, load the binary file, named “data.bin” to input buffer (via “load_binarary_file()”) before kernel launch.
• Launch to GPU kernel with single thread.

• In kernel function, initialize the file system we constructed.


• In kernel function, invoke user_program to simulate file operations for testing. We will replace the user program with different test cases.

• You should complete the file operations for
fs_open/fs_write/fs_read/fs_gsys(rm)/fs_gsys(ls_d)/fs_gsys(ls_s).

• In CPU(host) main function, the output buffer is copied in device, and it is written into “snapshot.bin” (via write_binarary_file()).
Function Requirements (90 points):
• Implement file volume structure. (10 points)
• Implement free space management. (For example, Bit-Vector / Bit-Map). (10 points)
• Implement contiguous allocation. (10 points)
• Implement fs_open operation (10 points)
• Implement fs_write operation (10 points)
• Implement fs_read operation (10 points)
• Implement fs_gsys(RM) operation (10 points)
• Implement fs_gsys(LS_D) operation (10 points)
• Implement fs_gsys(LS_S) operation (10 points)
Demo Output:
In the “user_program.cu”, we’ve provided three test cases.
• Test Case 1

• Test Case 2

• Test Case 3

Bonus (15 points)
• In basic task, there is only one root directory for the file system. In bonus, you must implement tree-structured directories. (3 points) • A directory (or subdirectory) contains a set of files or subdirectories.
• A directory is simply another file.
• There are at most 50 files (include subdirectories) in a directory.
• The size of a directory is the sum of character bytes of all files name
(include subdirectories).
E.g., the directory root/ have these files: “A.txt” “b.txt” “c.txt” “app”
The size of directory root/ is 22 bytes.
• The maximum number of files (include directory) is 1024.
• The maximum depth of the tree-structured directory is 3.
• File operations: (12 points) fs_gsys(fs, MKDIR, “app”); Create a directory named ‘app’.
 fs_gsys(fs, CD, “app”);
Enter app directory (only move to its subdirectory).
 fs_gsys(fs, CD_P); Move up to parent directory.
 fs_gsys(fs, RM_RF, “app”);
Remove the app directory and all its subdirectories and files recursively.
You cannot delete a directory by fs_gsys(fs, RM, “app”), cannot remove `app' if it is a directory.
 fs, gsys(fs, PWD);
Print the path name of current, eg., “/app/soft”
 fs_gsys(fs, LS_D / LS_S);
Update this file list operation, to list the files as well as directories. For a file, list it name (with size) only. For a directory, add an symbol ‘d’ at the end.
• Demo test case:

• Demo output:

Report (10 points)
Write a report(in PDF format) for your assignment, which should include main information as below:
• How did you design your program?
• What problems you met in this assignment and what is your solution?
• The steps to execute your program.
• Screenshot of your program output.
• What did you learn from this assignment?
Submission
• Please submit the file as package with directory structure as below:
Assignment_4_Student ID.zip
- Source
o Your project folder

o Within the folder ‘CSC3150_A4’, it should include files below:
• main.cu
• file_system.cu
• file_system.h
• user_program.cu
• data.bin
• snapshot.bin (auto generated after running your program)
- Bonus
o Your project folder

o Within the folder ‘CSC3150_A4_Bonus’, it should include files below:
• main.cu
• file_system.cu
• file_system.h
• user_program.cu
• data.bin
• snapshot.bin (auto generated after running your program)
- Report(PDF)
Grading rules
Report 10 points
Bonus 15 points
Completed with good
quality 80 ~ 90
Completed accurately 80 +
Fully Submitted
(compile successfully) 60 +
Partial submitted 0 ~ 60
No submission 0