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

[Mykola Ivanets]

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;
 
 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
+   * 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.
+     */
+    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.
-- 
2.17.2