Can anyone please explain this to me.
TIA,
raghu
On Mon, 23 Jun 2003, Raghu R. Arur wrote:
>
> 182 if (file) {
> 183 struct inode *inode = file->f_dentry->d_inode;
> 184 get_file(file);
> 185 if (tmp->vm_flags & VM_DENYWRITE)
> 186 atomic_dec(&inode->i_writecount);
> 187
>
> I was looking at the code of dup_mmap() in fork.c. I didnt understand
> something over here. The code above is checking whether the vm_area of the
> parent that the new process (child process)is copying, has read-only
> permission or read-write
> permission. If it has read-only permission then the inode's i_writecount
> is decremented. I saw in the vm documentation that if i_writecount is
> negative then it is read-only and if it is positive then it is positive.
> According to my understanding the inode data that we are accessing is
> global. So some processes might have read-only access
> to the file and some have read-write access to the file. So how can we
> decide whether the process has the correct access just by seeing the value
> of i_writecount of the inode. OR am i missing something over here.
>
> Can anyone please explain whats happening over here.
>
> thanks,
> raghu
> --
> Kernelnewbies: Help each other learn about the Linux kernel.
> Archive: http://mail.nl.linux.org/kernelnewbies/
> FAQ: http://kernelnewbies.org/faq/
>
--
Kernelnewbies: Help each other learn about the Linux kernel.
Archive: http://mail.nl.linux.org/kernelnewbies/
FAQ: http://kernelnewbies.org/faq/
