Re: lots of fstests cases fail on overlay with util-linux 2.40.2 (new mount APIs)

["Colin Walters" <walters@verbum.org>]

On Mon, Oct 28, 2024, at 8:22 AM, Christian Brauner wrote:
> On Sun, Oct 27, 2024 at 02:07:41AM +0800, Zorro Lang wrote:
>> Hi,
>> 
>> Recently, I hit lots of fstests cases fail on overlayfs (xfs underlying, no
>> specific mount options), e.g.
>> 
>> FSTYP         -- overlay
>> PLATFORM      -- Linux/s390x s390x-xxxx 6.12.0-rc4+ #1 SMP Fri Oct 25 14:29:18 EDT 2024
>> MKFS_OPTIONS  -- -m crc=1,finobt=1,rmapbt=0,reflink=1,inobtcount=1,bigtime=1 /mnt/fstests/SCRATCH_DIR
>> MOUNT_OPTIONS -- -o context=system_u:object_r:root_t:s0 /mnt/fstests/SCRATCH_DIR /mnt/fstests/SCRATCH_DIR/ovl-mnt
>> 
>> generic/294       [failed, exit status 1]- output mismatch (see /var/lib/xfstests/results//generic/294.out.bad)
>>     --- tests/generic/294.out	2024-10-25 14:38:32.098692473 -0400
>>     +++ /var/lib/xfstests/results//generic/294.out.bad	2024-10-25 15:02:34.698605062 -0400
>>     @@ -1,5 +1,5 @@
>>      QA output created by 294
>>     -mknod: SCRATCH_MNT/294.test/testnode: File exists
>>     -mkdir: cannot create directory 'SCRATCH_MNT/294.test/testdir': File exists
>>     -touch: cannot touch 'SCRATCH_MNT/294.test/testtarget': Read-only file system
>>     -ln: creating symbolic link 'SCRATCH_MNT/294.test/testlink': File exists
>>     +mount: /mnt/fstests/SCRATCH_DIR/ovl-mnt: fsconfig system call failed: overlay: No changes allowed in reconfigure.
>>     +       dmesg(1) may have more information after failed mount system call.
>
> In the new mount api overlayfs has been changed to reject invalid mount
> option on remount whereas in the old mount api we just igorned them.
> If this a big problem then we need to change overlayfs to continue
> ignoring garbage mount options passed to it during remount.

https://github.com/ostreedev/ostree/commit/bc62fd519631be6591c5c62302f83b45b9d56328 is related...I probably should have reported it at the time.