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

[Ralph Sennhauser]

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.

Thanks
Ralph