Re: [PATCH 5/6] btrfs-progs: mkfs: introduce experimental --subvol option

[Josef Bacik <josef@toxicpanda.com>]

On Mon, Oct 16, 2023 at 03:08:51PM +1030, Qu Wenruo wrote:
> Although mkfs.btrfs supports --rootdir to fill the target filesystem, it
> doesn't have the ability to create any subvolume.
> 
> This patch introduce a very basic version of --subvol for mkfs.btrfs,
> the limits are:
> 
> - No co-operation with --rootdir
>   This requires --rootdir to have extra handling for any existing
>   inodes.
>   (Currently --rootdir assumes the fs tree is completely empty)
> 
> - No multiple --subvol options supports
>   This requires us to collect and sort all the paths and start creating
>   subvolumes from the shortest path.
>   Furthermore this requires us to create subvolume under another
>   subvolume.
> 
> For now, this patch focus on the basic checks on the provided subvolume
> path, to wipe out any invalid things like ".." or something like "//////".
> 
> We support something like "//dir1/dir2///subvol///" just like VFS path
> (duplicated '/' would just be ignored).
> 
> Issue: #42
> Signed-off-by: Qu Wenruo <wqu@suse.com>
> ---
>  mkfs/main.c    |  23 ++++++++
>  mkfs/rootdir.c | 157 +++++++++++++++++++++++++++++++++++++++++++++++++
>  mkfs/rootdir.h |   1 +
>  3 files changed, 181 insertions(+)
> 
> diff --git a/mkfs/main.c b/mkfs/main.c
> index 42aa68b7ecf4..6bf30b758572 100644
> --- a/mkfs/main.c
> +++ b/mkfs/main.c
> @@ -434,6 +434,9 @@ static const char * const mkfs_usage[] = {
>  	"Creation:",
>  	OPTLINE("-b|--byte-count SIZE", "set size of each device to SIZE (filesystem size is sum of all device sizes)"),
>  	OPTLINE("-r|--rootdir DIR", "copy files from DIR to the image root directory"),
> +#if EXPERIMENTAL

I assume you're doing EXPERIMENTAL because you want to un-gate it once you
remove all the restrictions?  Thanks,

Josef