[CRIU] [PATCH] files: check fd flags after restore

[Stanislav Kinsburskiу]

15 дек. 2015 г. 12:31 PM пользователь Pavel Emelyanov <xemul at parallels.com> написал:
>
> On 12/14/2015 06:19 PM, Stanislav Kinsburskiy wrote: 
> > System call sys_fcntl() in _some_ kernels can silently drop some flags during 
> > set and return success code. 
>
> What are these flags? 
>

O_DIRECT and O_SYNC. Feature of openvz kernel.

> > This patch adds double check, that all the fd flags were really set. 
> > 
> > Signed-off-by: Stanislav Kinsburskiy <skinsbursky at virtuozzo.com> 
> > --- 
> >  files.c |   11 +++++++++++ 
> >  1 file changed, 11 insertions(+) 
> > 
> > diff --git a/files.c b/files.c 
> > index a27667d..751a9a9 100644 
> > --- a/files.c 
> > +++ b/files.c 
> > @@ -741,6 +741,17 @@ int set_fd_flags(int fd, int flags) 
> >  ret = fcntl(fd, F_SETFL, flags); 
> >  if (ret < 0) 
> >  goto err; 
> > + 
> > + /* Let's check, that now actual flags contains those we need */ 
> > + ret = fcntl(fd, F_GETFL, 0); 
> > + if (ret < 0) 
> > + goto err; 
> > + 
> > + if (ret != flags) { 
> > + pr_err("fcntl call on fd %d (flags %#o) succeeded, " 
> > + "but some flags were dropped: %#o\n", fd, flags, ret); 
> > + return -1; 
> > + } 
> >  return 0; 
> >  
> >  err: 
> > 
> > _______________________________________________ 
> > CRIU mailing list 
> > CRIU at openvz.org 
> > https://lists.openvz.org/mailman/listinfo/criu 
> > . 
> > 
>