file_struct

file

f_flags, f_pos, f_count, f_op, f_dentry

file_operations

IIseek, read, write, ioctl, open, release

inode_operations

link, unlink, symlink, mkdir, rmdir, rename, readlink, truncate

inode

i_uid, i_size, i_mode, i_op, i_sb

dentry cache

super_block

s_type, s_blocksize, s_root

disk

---------

PCB(Process Control Block)

文件描述符表 文件描述符

指针

file 结构体

File Status Flag (f_flag)

当前读写位置 (f_pos)

f_count: Reference Count

dup, fork

close

file_operations

dentry

open, stat

dentry cache

inode

inode_operations

super_block

s_root -> a certain dentry

VFS core concept:

these structs:

file, dentry, inode, superblock

ext2 VS

FAT32, NTFS of Windows: no concept of "inode" or "pemission"

--------- dup and dup2

open? which