[CRIU] Ghost file: no such file or directory

[Tycho Andersen]

On Wed, Mar 30, 2016 at 06:04:04PM +0300, Pavel Emelyanov wrote:
> On 03/30/2016 05:59 PM, Tycho Andersen wrote:
> > On Wed, Mar 30, 2016 at 05:50:32PM +0300, Pavel Emelyanov wrote:
> >> On 03/30/2016 05:46 PM, Tycho Andersen wrote:
> >>> On Wed, Mar 30, 2016 at 05:26:15PM +0300, Pavel Emelyanov wrote:
> >>>> On 03/30/2016 03:33 PM, Federico Reghenzani wrote:
> >>>>> Hi all!
> >>>>>
> >>>>> We have problem restoring Open MPI daemons with child processes that uses shared memory:
> >>>>>
> >>>>> (00.022447)    255: Opening ghost file 0x3 for tmp/openmpi-sessions-root at roaster-vm3_0/60995/1/shared_mem_pool.roaster-vm3.1
> >>>>> (00.022479)    255: Error (files-reg.c:139): Can't open ghost file //tmp/openmpi-sessions-root at roaster-vm3_0/60995/1/shared_mem_pool.roaster-vm3.1.cr.3.ghost: No such file or directory
> >>>>
> >>>> Can you check whether the \dirname of this path exists?
> >>>> I mean this -- //tmp/openmpi-sessions-root at roaster-vm3_0/60995/1/
> >>>>
> >>>> Presumably this is the case when not only the file was removed, but also
> >>>> some dir components. And we've fixed it only in 2.0.
> >>>
> >>> The users I had report it were using post 2.0, so there's some other
> >>> bug here. I'm trying to reproduce now again, but not having any luck
> >>> :(
> >>
> >> Do they also see the ENOENT errno from the open(O_CREAT) call?
> > 
> > Which call do you mean here? I don't see anything close to this that
> > does an O_CREAT on dump.
> 
> Yes, because the error is on restore :) For 1.8 this is files-reg.c create_ghost()'s

Oh, derp, I misread the error. I've seen failures reported on dump
here:

https://github.com/xemul/criu/blob/master/criu/files-reg.c#L628

which are presumably unrelated to this bug :). Sorry for the noise.

Tycho

> 	gfd = open(path, ghost_flags, gfe->mode);
>         if (gfd < 0) {
>                 pr_perror("Can't open ghost file %s", path);
>                 goto err;
>         }
> 
> -- Pavel