I'm still not able to figure out where exactly is the position of file stored per task_struct. struct file * itself is per process (task_struct) so file->f_pos is file position per process, if thats what you are looking for. I hope you haven't assumed that struct file itself is unique for a file, i.e. per inode? Then that assumption is wrong.
-Rajat On Tue, Jan 29, 2013 at 6:38 PM, Pranay Kumar Srivastava < Pranay.Shrivastava@hcl.com> wrote:
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?].
Regards, Pranay Kumar Srivastava
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