Re: generic/699 fails on ext4 due to using ext4 mount options w/ overlayfs

["Theodore Ts'o" <tytso@mit.edu>]

On Thu, Mar 20, 2025 at 04:01:42AM +0800, Zorro Lang wrote:
> Fstests supports overlayfs testing with different underlying fs, for example
> if you want to test overlay with ext4, you can set local.config as:
> 
>  FSTYP=ext4
>  TEST_DEV=/dev/sdb
>  TEST_DIR=/mnt/test
>  SCRATCH_DEV=/dev/sdc
>  SCRATCH_MNT=/mnt/scratch

Yes, I know.   My test appliances has autmation around setting local.config

> 
> then does:
> # mkfs.ext4 -F $TEST_DEV
> # mkfs.ext4 -F $SCRACH_DEV
> # mkdir /mnt/test
> # mkdir /mnt/scratch
> # ./check -overlay -g auto
> 
> For more details you can refer to xfstests/README.overlay.
> 
> Currently fstests only supports overlayfs testing as this, other fs, e.g. nfs,
> has to prepare nfs SCRATCH_DEV and TEST_DEV by the user. I'm thinking about
> supporting other upper fs testing likes overlay (if it's helpful).

I have automation that handles this, so I'm good:

./kvm-xfstests --primary-fstype xfs -c overlay/default -g auto

My point was that might be the reason why it might be convenient for
the test generic/699 being in generic/ instead of overlay/, since it
means that people who are runing a large number of configs, e.g.:

./kvm-xfstests -c ext4/default,xfs/default,btrfs/default generic/699

can easily test overlayfs with idmapping with different underlying
file systems.  (Note: this is where my automation will write to
local.config while iterating across different file system configs).

Is it worth regularly running generic/699 across multiple underyling
file systmes?  I dunno; I'll let other people chime in on it, since I
don't really use overayfs with idmapping myself, and I haven't
examined the code paths in question myself.

Cheers,

					- Ted