Re: generic_file_write code segment in 2.2.18

[Asang K Dani <asang@yahoo.com>]

--- Andi Kleen <ak@suse.de> wrote:
> On Thu, Jan 04, 2001 at 10:42:34PM +0000, Stephen C. Tweedie wrote:
> > No, because then you'd be skipping the updatepage() call if we
> took a
> > fault mid-copy after copying some data.  That would imply you had
> > dirtied the page cache without an updatepage().
> > 
> > The current behaviour should just result in a short IO, which
> should
> > be fine.
> 
> The problem is that the short write is not reported to the caller,
> even when only zero bytes are copied (the page is corrupted anyways
> though because cfu  zeros the uncopied rest).  

I think it will be reported to caller, because when cfu copies 0
bytes,

   bytes -= copy_from_user(dest, buf, bytes);

will make 'bytes' zero. Since 'bytes' is 'zero' updatepage will not
be called and status retains value '-EFAULT' and it breaks out of
the while loop immediately.

> 
> -Andi

asang..

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