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

[Amir Goldstein]

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.

Thanks!