[REGRESSION 4.11] Commit d8514d8edb5b ("ovl: copy up regular file using O_TMPFILE") breaks ubifs

[Ralph Sennhauser]

On Tue, 28 Mar 2017 08:08:51 -0400
Amir Goldstein <amir73il at gmail.com> wrote:

> On Tue, Mar 28, 2017 at 7:28 AM, Ralph Sennhauser
> <ralph.sennhauser at gmail.com> wrote:
> > Hi Amir,
> >
> > On Tue, 28 Mar 2017 07:03:11 -0400
> > Amir Goldstein <amir73il at gmail.com> wrote:
> >  
> >> Overlayfs now uses O_TMPFILE for copy up and it works fine with all
> >> the file systems I tested (tmpfs, xfs, ext4).
> >> If I am right and O_TMPFILE is broken in ubifs, you are most likely
> >> the first person to test it (indirectly by overlayfs).
> >>
> >> Please try to reproduce the bug with following patch to disable
> >> ubifs O_TMPFILE support:
> >>
> >> --- a/fs/ubifs/dir.c
> >> +++ b/fs/ubifs/dir.c
> >> @@ -1685,7 +1685,7 @@ const struct inode_operations
> >> ubifs_dir_inode_operations = {
> >>  #ifdef CONFIG_UBIFS_ATIME_SUPPORT
> >>         .update_time = ubifs_update_time,
> >>  #endif
> >> -       .tmpfile     = ubifs_tmpfile,
> >> +       //.tmpfile     = ubifs_tmpfile,
> >>  };  
> >
> > Get a unused warning during build but all seems to be working fine
> > now. 
> 
> OK. I'll wait for ubifs developers to fix the bug.
> Otherwise, I'll send a proper patch to disable ubifs O_TMPFILE
> support. Will add tested-by you.

Sounds like a good plan, there is still time for 4.11-rc5. Fine with
you adding my tested-by in case it will come to this.

Appreciated
Ralph

> 
> Thanks!