[CRIU] [PATCH 1/2] zdtm: introduced a local version of O_LARGEFILE

[Cyrill Gorcunov]

On Thu, Jan 31, 2013 at 01:16:43AM +0400, Pavel Emelyanov wrote:
> On 01/30/2013 03:53 PM, Cyrill Gorcunov wrote:
> > On Wed, Jan 30, 2013 at 03:35:14PM +0400, Pavel Emelyanov wrote:
> >> On 01/30/2013 10:32 AM, Alexander Kartashov wrote:
> >>> On 01/30/2013 03:13 AM, Pavel Emelyanov wrote:
> >>>> In what header?
> >>> It's the header /usr/include/x86_64-linux-gnu/bits/fcntl.h in my distro.
> >>>> OK, so zdtm test opens file with O_LARGEFILE flag, doesn't it?
> >>>
> >>> The test static/file_fown tests C/R of pipes. Descriptors of pipe ends
> >>> are created by the kernel without the flag O_LARGEFILE. crtools dumps
> >>> everything correctly.
> >>>
> >>> When a pipe is restored one of its ends is reopened using the function
> >>> open() that adds the flag O_LARGEFILE specifically its kernel version.
> >>> So the test detects that file flags on a pipe descriptor changed during
> >>> the C/R cycle and reports a error.
> >>
> >> It's a bug in crtools. O_LARGEFILE shouldn't appear on an FD.
> > 
> > As far as I see we indeed receive pipe end as
> > 
> > static int recv_pipe_fd(struct pipe_info *pi)
> > {
> > 	...
> > 	tmp = recv_fd(fd);
> > 	if (tmp < 0) {
> > 		pr_err("Can't get fd %d\n", tmp);
> > 		return -1;
> > 	}
> > 	close(fd);
> > 
> > 	snprintf(path, sizeof(path), "/proc/self/fd/%d", tmp);
> > 	fd = open(path, pi->pe->flags);
> > 
> > 	here the kernel will add O_LARGEFILE if bits-per-long != 32,
> > 	ie on x86-64, this is side effect of open system call, i'm
> > 	not sure how can we escape this.
> 
> Try calling rst_file_parms afterwards.

If only I've not missed something obvious (it's nitgh and i'm somehow
semisleep already :) it won't does the trick

#define SETFL_MASK (O_APPEND | O_NONBLOCK | O_NDELAY | O_DIRECT | O_NOATIME)

static int setfl(int fd, struct file * filp, unsigned long arg)
{
	...
	spin_lock(&filp->f_lock);
	filp->f_flags = (arg & SETFL_MASK) | (filp->f_flags & ~SETFL_MASK);
	spin_unlock(&filp->f_lock);

where the args is the new flags set.

	Cyrill