[Libguestfs] [PATCH 1/1] virt-make-fs: add '--blocksize' option support

[Richard W.M. Jones]

On Wed, Feb 19, 2020 at 02:09:29AM +0200, Mykola Ivanets wrote:
> From: Nikolay Ivanets <stenavin at gmail.com>
> 
> This patch adds '--blocksize' command line option for virt-make-fs
> tool.  This option allows specifying disk sector size as described in
> 'guestfs_add_drive_opts' libguestfs API.
> ---
>  make-fs/make-fs.c            | 28 ++++++++++++++++++++++++++--
>  make-fs/test-virt-make-fs.sh |  5 ++++-
>  make-fs/virt-make-fs.pod     | 10 ++++++++++
>  3 files changed, 40 insertions(+), 3 deletions(-)
> 
> diff --git a/make-fs/make-fs.c b/make-fs/make-fs.c
> index 5d8c3a385..81d1cf90b 100644
> --- a/make-fs/make-fs.c
> +++ b/make-fs/make-fs.c
> @@ -54,10 +54,12 @@ int in_virt_rescue = 0;
>  
>  static const char *format = "raw", *label = NULL,
>    *partition = NULL, *size_str = NULL, *type = "ext2";
> +int blocksize = 0;

Needs to be a static int.

>  enum { HELP_OPTION = CHAR_MAX + 1 };
>  static const char options[] = "F:s:t:Vvx";
>  static const struct option long_options[] = {
> +  { "blocksize", 1, 0, 0 },
>    { "debug", 0, 0, 'v' }, /* for compat with Perl tool */
>    { "floppy", 0, 0, 0 },
>    { "format", 1, 0, 'F' },
> @@ -87,6 +89,7 @@ usage (int status)
>                "  %s [--options] input.tar.gz output.img\n"
>                "  %s [--options] directory output.img\n"
>                "Options:\n"
> +              "  --blocksize=512|4096     Set sector size of the output disk\n"
>                "  --floppy                 Make a virtual floppy disk\n"
>                "  -F|--format=raw|qcow2|.. Set output format\n"
>                "  --help                   Display brief help\n"
> @@ -146,6 +149,9 @@ main (int argc, char *argv[])
>            partition = "mbr";
>          else
>            partition = optarg;
> +      } else if (STREQ (long_options[option_index].name, "blocksize")) {
> +        if (sscanf (optarg, "%d", &blocksize) != 1)
> +          error (EXIT_FAILURE, 0, _("--blocksize option is not numeric"));
>        } else
>          error (EXIT_FAILURE, 0,
>                 _("unknown long option: %s (%d)"),
> @@ -678,11 +684,23 @@ do_make_fs (const char *input, const char *output_str)
>               estimate, estimate / 1024, estimate / 4096);
>    }
>  
> +  /* For partition alignment and extra space at the end of the disk:
> +   * by default we create first partition at 128 sector boundary and leave the

Best to keep lines under 78 or so characters long.  In emacs you can
use M-q (Esc q) to automatically format the comment.

> +   * last 128 sectors at the end of the disk free.
> +   */
> +  if (partition)
> +    estimate += 2 * 128 * blocksize;
> +
>    estimate += 256 * 1024;       /* For superblocks &c. */
>  
>    if (STRPREFIX (type, "ext") && type[3] >= '3') {
> -    /* For ext3+, add some more for the journal. */
> -    estimate += 1024 * 1024;
> +    /* For ext3+, add some more for the journal.  Journal should be at least
> +     * 1024 file system blocks.  By default file system block size is 1024 bytes
> +     * if disk sector size is 512 bytes and 4096 bytes if disk sector size is
> +     * 4096 bytes.  Note that default file system block size may be changed via
> +     * /etc/mke2fs.conf but we cannot handle that at the moment.
> +     */

Same here about the length of lines.

> +    estimate += 1024 * (blocksize == 512 ? 1024 : 4096);
>    }
>  
>    else if (STREQ (type, "ntfs")) {
> @@ -697,6 +715,11 @@ do_make_fs (const char *input, const char *output_str)
>      estimate += 256 * 1024 * 1024;
>    }
>  
> +  else if (STREQ (type, "xfs")) {
> +    /* xfs requires at least 4096 blocks.  Default block size is 4096 bytes. */
> +    estimate += 4096 * 4096;
> +  }
> +
>    /* Add 10%, see above. */
>    estimate *= 1.10;
>  
> @@ -718,6 +741,7 @@ do_make_fs (const char *input, const char *output_str)
>  
>    if (guestfs_add_drive_opts (g, output,
>                                GUESTFS_ADD_DRIVE_OPTS_FORMAT, format,
> +                              GUESTFS_ADD_DRIVE_OPTS_BLOCKSIZE, blocksize,
>                                -1) == -1)
>      return -1;
>  
> diff --git a/make-fs/test-virt-make-fs.sh b/make-fs/test-virt-make-fs.sh
> index 79d058b6a..01c332b1d 100755
> --- a/make-fs/test-virt-make-fs.sh
> +++ b/make-fs/test-virt-make-fs.sh
> @@ -83,9 +83,12 @@ size=`random_choice`
>  choices=("" --label=FOO)
>  label=`random_choice`
>  
> +choices=(--blocksize=512 --blocksize=4096)
> +blocksize=`random_choice`
> +
>  if [ -n "$LIBGUESTFS_DEBUG" ]; then debug=--debug; fi
>  
> -params="$type $format $partition $size $label $debug"
> +params="$type $format $partition $size $label $blocksize $debug"
>  echo "test-virt-make-fs: parameters: $params"
>  
>  rm -f test.file test.tar output.img
> diff --git a/make-fs/virt-make-fs.pod b/make-fs/virt-make-fs.pod
> index 76ccbd120..bd4802c7c 100644
> --- a/make-fs/virt-make-fs.pod
> +++ b/make-fs/virt-make-fs.pod
> @@ -122,6 +122,16 @@ or rerun virt-make-fs to build another image from scratch.
>  
>  Display brief help.
>  
> +=item B<--blocksize=512>
> +
> +=item B<--blocksize=4096>
> +
> +This parameter sets the sector size of the output disk image.
> +
> +The default is C<512> bytes.
> +
> +See also L<guestfs(3)/guestfs_add_drive_opts>.
> +
>  =item B<--floppy>
>  
>  Create a virtual floppy disk.

Patch looks good apart from those few minor things.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
libguestfs lets you edit virtual machines.  Supports shell scripting,
bindings from many languages.  http://libguestfs.org