Re: [PATCH] fstests: support new mkfs.btrfs help string

[Zorro Lang <zlang@kernel.org>]

On Sun, May 10, 2026 at 09:47:04AM +0930, Qu Wenruo wrote:
> [BUG]
> The latest btrfs-progs release v7.0 breaks a lot of tests, e.g.
> btrfs/003:
> 
> btrfs/003    55s ... [failed, exit status 1]- output mismatch (see /home/kts/kernel-test-suite/src/xfstests/results//btrfs/003.out.bad)
>     --- tests/btrfs/003.out     2026-05-09 03:07:52.952213772 +0900
>     +++ /home/kts/kernel-test-suite/src/xfstests/results//btrfs/003.out.bad     2026-05-09 23:32:17.595751435 +0900
>     @@ -1,2 +1,3 @@
>      QA output created by 003
>     -Silence is golden
>     +mkfs failed
>     +(see /home/kts/kernel-test-suite/src/xfstests/results//btrfs/003.full for details)
>     ...
>     (Run 'diff -u /home/kts/kernel-test-suite/src/xfstests/tests/btrfs/003.out /home/kts/kernel-test-suite/src/xfstests/results//btrfs/003.out.bad'  to see the entire diff)
> 
> [CAUSE]
> Commit ec8324cc4b8b ("btrfs-progs: help: adjust alignment of text") from
> btrfs-progs changed the helpe string output format, the previous help
> string for "-f" option of mkfs.btrfs looks like this:
> 
>     -f|--force                force overwrite of existing filesystem
> 
> There were 4 spaces before the "-f", thus can be matched by
> "[[:space:]]-f[[:space]|,]".
> 
> But now the help string looks like:
> 
> -f, --force               force overwrite of existing filesystem
> 
> Which removed the spaces at the beginning.
> 
> The existing regex to catch "-f" requires at least one space before
> "-f", now it doesn't match the new btrfs help string, and cause mkfs
> failure because we can not overwrite an existing scratch device without
> "-f" option.
> 
> [FIX]
> Change the regex to allow no space before "-f".
> 
> Reported-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
> Link: https://lore.kernel.org/linux-btrfs/af9EHC5b-aBdr1zn@shinmob/
> Signed-off-by: Qu Wenruo <wqu@suse.com>
> ---
>  common/config | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/common/config b/common/config
> index 1420e35d..339f7767 100644
> --- a/common/config
> +++ b/common/config
> @@ -103,7 +103,7 @@ set_mkfs_prog_path_with_opts()
>  	# Note: mkfs.f2fs doesn't support the --help option yet, but it doesn't
>  	# matter since it also prints the help when an invalid option is given.
>  	if [ "$p" != "" ] && \
> -		$p --help |& grep -q "[[:space:]]-f[[:space:]|,]"; then
> +		$p --help |& grep -q "[[:space:]]*-f[[:space:]|,]"; then

Hi Qu,

This change looks good to me. But to be a bit nitpicky, the original
"[[:space:]]-f" required *a* mandatory [space] before the -f, whereas
"[[:space:]]*-f" allows for *zero* or more spaces. This changes the
semantics slightly, but it makes sense if you're trying to match cases
where -f appears at the very beginning of a line.

If that wasn't your intention or if you find this behavior unexpected, let me
know :) Otherwise, I'd like to:

Reviewed-by: Zorro Lang <zlang@kernel.org>

>  		echo "$p -f"
>  	else
>  		echo $p
> -- 
> 2.51.2
> 
>