green = correct

red = wrong

Initial state
inode bitmap  10000000
inodes        [d a:0 r:2] [] [] [] [] [] [] [] 
data bitmap   10000000
data          [(.,0) (..,0)] [] [] [] [] [] [] [] 

1. creat("/f");


inode bitmap   
11000000
inodes   
[da:0r:2][fa:-1r:1][][][][][][]
data bitmap   
10000000
data   
[(.,0)(..,0)(f,1)][][][][][][][]
2. creat("/o");


inode bitmap   
11100000
inodes   
[da:0r:2][fa:-1r:1][fa:-1r:1][][][][][]
data bitmap   
10000000
data   
[(.,0)(..,0)(f,1)(o,2)][][][][][][][]
3. link("/f", "/v");


inode bitmap   
11100000
inodes   
[da:0r:2][fa:-1r:2][fa:-1r:1][][][][][]
data bitmap   
10000000
data   
[(.,0)(..,0)(f,1)(o,2)(v,1)][][][][][][][]
4. mkdir("/p");


inode bitmap   
11110000
inodes   
[da:0r:3][fa:-1r:2][fa:-1r:1][da:1r:2][][][][]
data bitmap   
11000000
data   
[(.,0)(..,0)(f,1)(o,2)(v,1)(p,3)][(.,3)(..,0)][][][][][][]
5. fd=open("/o", O_WRONLY|O_APPEND); write(fd, "l", BLOCKSIZE); close(fd);


inode bitmap   
11110000
inodes   
[da:0r:3][fa:-1r:2][fa:2r:1][da:1r:2][][][][]
data bitmap   
11100000
data   
[(.,0)(..,0)(f,1)(o,2)(v,1)(p,3)][(.,3)(..,0)][l][][][][][]
6. link("/o", "/p/s");


inode bitmap   
11110000
inodes   
[da:0r:3][fa:-1r:2][fa:2r:2][da:1r:2][][][][]
data bitmap   
11100000
data   
[(.,0)(..,0)(f,1)(o,2)(v,1)(p,3)][(.,3)(..,0)(s,2)][l][][][][][]