ui: add --align command-line option to specify mkpart alignment

The new --align command-line option can have the following values:
none:     Use the minimum alignment allowed by the disk type
cylinder: Align partitions to cylinders (the default)
minimal: Use minimum alignment as given by the disk topology information
optimal: Use optimum alignment as given by the disk topology information

Note the "minimal" and "optimal" values will use layout information
provided by the disk to align the logical partition table addresses
to actual physical blocks on the disks.  The "minimal" value is the
minimum aligment needed to align the partition properly to physical
blocks, which avoids performance degradation.  Whereas the "optimum"
alignment align's to a multiple of the physical block size in a way
that guarantees optimal performance.

The "minimal" and "optimal" values are useful only when parted is
compiled with libblkid >= 2.17 and running on a kernel >= 2.6.31,
otherwise they are equivalent to --align=none.

* parted/parted.c (ALIGNMENT_ enum values): New enum.
(options, options_help): Add --align option.
(align_args, align_types, alignment): New global variables.
(do_mkpart): Honor aligment variable.
(_parse_options): handle --align option.
* bootstrap.conf (gnulib_modules): Add argmatch.
* NEWS: Mention the new --align option.
* doc/parted.texi: Document --align option.
* doc/C/parted.8: Likewise.

1 files changed, 20 insertions, 0 deletions

diff --git a/doc/C/parted.8 b/doc/C/parted.8
index 9909ba8..2a8992e 100644
--- a/doc/C/parted.8
+++ b/doc/C/parted.8
@@ -30,6 +30,26 @@ never prompts for user intervention
 .TP
 .B -v, --version
 displays the version
+.TP
+.B -a \fIalignment-type\fP, --align \fIalignment-type\fP
+Set alignment for newly created partitions, valid alignment types are:
+.RS
+.IP none
+Use the minimum alignment allowed by the disk type.
+.IP cylinder
+Align partitions to cylinders.
+.IP minimal
+Use minimum alignment as given by the disk topology information. This and
+the opt value will use layout information provided by the disk to align the
+logical partition table addresses to actual physical blocks on the disks.
+The min value is the minimum aligment needed to align the partition properly to
+physical blocks, which avoids performance degradation.
+.IP optimal
+Use optimum alignment as given by the disk topology information. This
+aligns to a multiple of the physical block size in a way that guarantees
+optimal performance.
+.RE
+
 .SH COMMANDS
 .TP
 .B [device]