Re: [PATCH] fstests: generic/500 doesn't work for btrfs

["Darrick J. Wong" <darrick.wong@oracle.com>]

On Thu, Aug 15, 2019 at 02:26:59PM -0400, Josef Bacik wrote:
> Btrfs does COW, so when we unlink the file we need to update metadata
> and write it to a new location, which we can't do because the thinp is
> full.  This results in an EIO during a metadata write, which makes us
> flip read only, thus making it impossible to fstrim the fs.  Just make
> it so we skip this test for btrfs.
> 
> Signed-off-by: Josef Bacik <josef@toxicpanda.com>
> ---
>  tests/generic/500 | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/tests/generic/500 b/tests/generic/500
> index 201d8b9f..5cd7126f 100755
> --- a/tests/generic/500
> +++ b/tests/generic/500
> @@ -49,6 +49,12 @@ _supported_os Linux
>  _require_scratch_nocheck
>  _require_dm_target thin-pool
>  
> +# The unlink below will result in new metadata blocks for btrfs because of CoW,
> +# and since we've filled the thinp device it'll return EIO, which will make
> +# btrfs flip read only, making it fail this test when it just won't work right
> +# for us in the first place.
> +test $FSTYP == "btrfs"  && _notrun "btrfs doesn't work that way lol"

I did it for the lulz,
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>

--D

> +
>  # Require underlying device support discard
>  _scratch_mkfs >>$seqres.full 2>&1
>  _scratch_mount
> -- 
> 2.21.0
>