On Tue, Apr 14, 2015 at 11:06:40AM +0800, Joseph Qi wrote:
> Hi Viro,
> I have questions about your commit cf1b5ea1c5cd
> ("[regression] ocfs2: do *not* increment ->ki_pos twice").
> Yes, ->ki_pos is increased in generic_file_direct_write(). But
> *ppos doesn't. So I increase it here for further use in
> generic_perform_write.
> After this, ->ki_pos and *ppos are equal.They are equal all along, for a very simple reason: ppos *points* *to* iocb->ki_pos. So yes, you do increase it twice, once via one alias, once via another. Check and you'll see - ppos is initialized with &iocb->ki_pos and never reassigned. What happens is an equivalent of int x = 0; int *p = &x; x += 10; *p += 10; which obviously ends with x increased by 20, not by 10... _______________________________________________ Ocfs2-devel mailing list Ocfs2-devel@oss.oracle.com https://oss.oracle.com/mailman/listinfo/ocfs2-devel
