Where does kernel store per task file position?

Pranay Kumar Srivastava Pranay.Shrivastava at hcl.com
Tue Jan 29 08:08:42 EST 2013

Hi Everyone,

I was trying to find out where does Linux store per process file position? Since struct file is allocated once when the file is first opened (get_empty_filp() via do_sys_open) .I looked at these,

Copy_process--->copy_files-->dup_fd  it seemed to allocate only (struct file*)

struct files_struct , but I couldn't find any field that is actually being used to store the file position.

I'm still not able to figure out where exactly is the position of file stored per task_struct. Secondly even if this was being saved does the kernel changes f_pos of struct file whenever a (read/write) is done? I don't that happens [Correct?].

Pranay Kumar Srivastava


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