Filesystem
I Gebze Technical University Department of Computer Engineering CSE 312 /CSE 504 Operating Systems Spring 2020 Midterm Exam Project Due Date: May31st 2020 File Systems In this project, you will design and implement a simplifies UNIX like file system in C or C++. This project does not use MIPS or SPIM, so it is completely independent of your other homework assignments. This will count as midterm exam for this course. Part 1 Design a file system that uses i-nodes blocks and data blocks to keep your files. Your file system will use, a i-node structure like Fig 4.33 of your textbook (single link, double link and triple link i-nodes). Your directory, i-node block , data block structure will be similar to Fig 4.34 of the textbook. Your file attributes will include size, last modification date and time, and name of the file. No permissions or owner attributes will be kept. Write a design report that specifies the following • Define yourdirectory structure and directory entries; • Define how you keep the free blocks and free i-nodes; • Define your i-node structure • Define your superblock that contains crucial information about the file system such as the block size, i-node positions, block positions, etc. Your report should include the function names of your source code that handles the file system operations listed in the table of Part 3. Part 2 Write a C/C++ program that creates an empty file system as a 1 MB Linux file. This file will include all the information about your file system including the i-nodes, data blocks, free blocks and i-nodes, directories, data, etc. The sample run of the program will be like makeFileSystem 4 400 mySystem.dat where 4 is the block size of the file system in KB for both data blocks and i-node blocks, and 400 is the number of free i-nodes for an empty file system. mySystem.dat is the Linux file that contains all the file system. When you work on the file system, this file contains all the information for the file system. Note that the size of mySystem.dat will be exactly 1 MB all the time whether it contains any information or not. Part 3 You will write a program that performs file system operation on the file system. The program will work like following fileSystemOper fileSystem.data operation parameters where fileSystemOper is your program, fileSystem.data is the file system data file that you have created in Part 2. You will keep modifying the same fileSystem.data file for all your operations. Allowable operations and parameters for these operations are given below in the following table. II Operation Parameters Explanation Example list Path Lists the contents of the directory shown by path on the screen. fileSystemOper fileSystem.data list“/” lists the contents of the root directory. The output will be similar to ls –l mkdir rmdir Path and dir name Makes or removes a directory fileSystemOper fileSystem.data mkdir“/usr/ysa” makes a new directory under the directory “ysa” if possible. These two works exactly like mkdir and rmdir commands of Linux shell dumpe2fs None Gives information about the file system. fileSystemOper fileSystem.data dumpe2fs works like simplified and modified Linux dumpe2fs command. It will list block count, i-node count, free block and i-nodes, number of files and directories, and block size. Different from regular dumpe2fs, this command lists all the occupied i-nodes, blocks and the file names for each of them. write Path and file name Creates and writes data to the file fileSystemOper fileSystem.data write“/usr/ysa/file”linuxFile Creates a file named file under “/usr/ysa” in your file system, then copies the contents of the Linux file into the new file. This works very similar to Linux copy command. read Path and file name Reads data from the file fileSystemOper fileSystem.data read “/usr/ysa/file”linuxFile Readsthe file named file under “/usr/ysa” in your file system, then writes this data to the Linux file. This again works very similar to Linux copy command. del Path and file name Deletes file from the path fileSystemOper fileSystem.data del “/usr/ysa/file” Deletes the file named file under “/usr/ysa” in your file system. This again works very similar to Linux del command. Operations below are bonus (20 points) ln Source and destination path and file names Hard linking between 2 files fileSystemOper fileSystem.data ln“/usr/ysa/file1” “/usr/ysa/file2” Allows more than one filename to refer to the same file Linux ln command lnsym Source and destination path and file names Symbolic linking between 2 files fileSystemOper fileSystem.data lnsym “/usr/ysa/file1” “/usr/ysa/file2” Linux ln-s command fsck none Simplified File system check fileSystemOper fileSystem.data fsck Just print the two table of Fig 4.27 of your text book for both i- nodes and blocks Here is a sequence file system operation commands that you can use to test your file system. Suppose you have a file named linuxFile.data in your Linux current directory. makeFileSystem 4 400 mySystem.data III fileSystemOper fileSystem.data mkdir“/usr” fileSystemOper fileSystem.data mkdir“/usr/ysa” fileSystemOper fileSystem.data mkdir“/bin/ysa” ; Should print error! fileSystemOper fileSystem.data write “/usr/ysa/file1” linuxFile.data fileSystemOper fileSystem.data write “/usr/file2” linuxFile.data fileSystemOper fileSystem.data write “/file3” linuxFile.data fileSystemOper fileSystem.data list “/” ; Should list 1 dir, 1 file fileSystemOper fileSystem.datadel “/usr/ysa/file1” fileSystemOper fileSystem.data dumpe2fs fileSystemOper fileSystem.data read “/usr/file2” linuxFile2.data cmp linuxFile2.data linuxFile.data ; Should not print any difference fileSystemOper fileSystem.data ln “/usr/file2” “/usr/linkedfile2” fileSystemOper fileSystem.data list “/usr" fileSystemOper fileSystem.data write “/usr/linkedfile2” linuxFile.data fileSystemOper fileSystem.data dumpe2fs fileSystemOper fileSystem.data lnsym “/usr/file2” “/usr/symlinkedfile2” fileSystemOper fileSystem.data list “/usr" fileSystemOper fileSystem.data del “/usr/file2” fileSystemOper fileSystem.data list “/usr" ; Should see likedfile2 is there, symlinkedFile2 is there but.. fileSystemOper fileSystem.data write “/usr/symlinkedfile2” linuxFile.data ; Should print error! fileSystemOper fileSystem.data dumpe2fs Notes 1. Always be careful about the errors, such as bad block sizes, bad file names, non-existent files or directories, etc. 2. Run experiments that uses up all of your i-nodes and data blocks. 3. Try to get fragmentation and show your fragmented file system using the dumpe2fs command. 4. Do not use any code from any other source even a single line! IV General Homework Guidelines 1. No cheating, No copying, No peaking to other peoplehomework 2. Follow the instructions verycarefully. 3. Send required files only. Do not share your whole file system withus. 4. If you fail to implement one of the requirements, leave it be. Do not send an emptyfile 5. Respect the file names! Our HW grading iscase-sensitive. 6. Failing to comply any of the warnings above will result in getting a 0 for your current homework. Homework Instructions 1. Download and Install Vmware Player from Officialsite. 2. Download and install our virtual machine fromhttps://drive.google.com/open?id=1YppX3lNkyTsHV_lvA4w9TomNCUkpLeEg https://drive.google.com/open?id=1YppX3lNkyTsHV_lvA4w9TomNCUkpLeEg https://drive.google.com/open?id=1YppX3lNkyTsHV_lvA4w9TomNCUkpLeEg