Re: [PATCH] fstests: btrfs/012 don't follow symlinks for populating $SCRATCH_MNT

[Roman Mamedov <rm@romanrm.net>]

On Fri, 24 Mar 2023 16:13:19 -0400
Josef Bacik <josef@toxicpanda.com> wrote:

> /lib/modules/$(uname -r)/ can have symlinks to the source tree where the
> kernel was built from, which can have all sorts of stuff, which will
> make the runtime for this test exceedingly long.  We're just trying to
> copy some data into our tree to test with, we don't need the entire
> devel tree of whatever we're doing, so use -P to not follow symlinks
> when copying.
> 
> Signed-off-by: Josef Bacik <josef@toxicpanda.com>
> ---
>  tests/btrfs/012 | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/tests/btrfs/012 b/tests/btrfs/012
> index d9faf81c..1b6e8a6b 100755
> --- a/tests/btrfs/012
> +++ b/tests/btrfs/012
> @@ -43,7 +43,7 @@ mount -t ext4 $SCRATCH_DEV $SCRATCH_MNT
>  
>  _require_fs_space $SCRATCH_MNT $(du -s /lib/modules/`uname -r` | ${AWK_PROG} '{print $1}')
>  
> -cp -aR /lib/modules/`uname -r`/ $SCRATCH_MNT
> +cp -aPR /lib/modules/`uname -r`/ $SCRATCH_MNT

But did you face the described problem in actual operation?

"man cp" says 

       -a, --archive
              same as -dR --preserve=all
...
       -d     same as --no-dereference --preserve=links
...
       -P, --no-dereference
              never follow symbolic links in SOURCE

So -a includes -d, which already includes -P that is now being added.

Moreover, even -R is redundant in the original line and could be removed.

-- 
With respect,
Roman