Re: [Libguestfs] [PATCH 1/1] WIP: sparsify: Support LUKS-encrypted partitions

Richard W.M. Jones
Tue, 21 Jan 2020 14:56:14 -0000

On Tue, Jan 21, 2020 at 03:07:12PM +0100, Jan Synacek
wrote:
> ---
>  daemon/listfs.ml | 18 +++++++++++++++---
>  daemon/luks.c    |  1 +
>  2 files changed, 16 insertions(+), 3 deletions(-)
>
> diff --git a/daemon/listfs.ml b/daemon/listfs.ml
> index bf4dca6d4..48880f2e5 100644
> --- a/daemon/listfs.ml
> +++ b/daemon/listfs.ml
> @@ -19,6 +19,7 @@
>  open Printf
>
>  open Std_utils
> +open Utils
>
>  (* Enumerate block devices (including MD, LVM, LDM and partitions) and use
>   * vfs-type to check for filesystems on devices.  Some block devices
cannot
> @@ -30,6 +31,7 @@ let rec list_filesystems () >
>    (* Devices. *)
>    let devices = Devsparts.list_devices () in
> +
>    let devices = List.filter is_not_partitioned_device devices in
>    let ret = List.filter_map check_with_vfs_type devices in
>
> @@ -144,9 +146,19 @@ and check_with_vfs_type device >    else if
String.is_suffix vfs_type "_member" then
>      None
>
> -  (* Ignore LUKS-encrypted partitions.  These are also containers, as
above. *)
> -  else if vfs_type = "crypto_LUKS" then
> -    None
> +  (* If a LUKS-encrypted partition had been opened, include the
corresponding
> +   * device mapper filesystem path. *)
> +  else if vfs_type = "crypto_LUKS" then (
> +    let out = command "lsblk" ["-n"; "-l";
"-o"; "NAME"; device] in
> +      (* Example output: #lsblk -n -l -o NAME /dev/sda5
> +       * sda5
> +       * lukssda5
> +       *)
> +      match String.trimr @@ snd @@  String.split "\n" out with
> +      | "" -> None
> +      | part -> let mnt = Mountable.of_path @@ "/dev/mapper/"
^ part in

As a matter of style I'd put the "let" on a new line.

> +          Some [mnt, Blkid.vfs_type mnt]
> +  )
>
>    (* A single btrfs device can turn into many volumes. *)
>    else if vfs_type = "btrfs" then (
> diff --git a/daemon/luks.c b/daemon/luks.c
> index d631cb100..1ffeaf293 100644
> --- a/daemon/luks.c
> +++ b/daemon/luks.c
> @@ -110,6 +110,7 @@ luks_open (const char *device, const char *key, const
char *mapname,
>    ADD_ARG (argv, i, "-d");
>    ADD_ARG (argv, i, tempfile);
>    if (readonly) ADD_ARG (argv, i, "--readonly");
> +  ADD_ARG (argv, i, "--allow-discards");
>    ADD_ARG (argv, i, "luksOpen");
>    ADD_ARG (argv, i, device);
>    ADD_ARG (argv, i, mapname);

Seems fine except for considering if --allow-discards should
be a flag (boolean optarg) for the luks_open API.

Rich.

--
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
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