on i386 and amd64 machines. The overall process is that /boot/pmbr lives
in the PMBR (similar to /boot/mbr for MBR disks) and is responsible for
locating and loading /boot/gptboot. /boot/gptboot is similar to /boot/boot
except that it groks GPT rather than MBR + bsdlabel. Unlike /boot/boot,
/boot/gptboot lives in its own dedicated GPT partition with a new
"FreeBSD boot" type. This partition does not have a fixed size in that
/boot/pmbr will load the entire partition into the lower 640k. However,
it is limited in that it can only be 545k. That's still a lot better than
the current 7.5k limit for boot2 on MBR. gptboot mostly acts just like
boot2 in that it reads /boot.config and loads up /boot/loader. Some more
details:
- Include uuid_equal() and uuid_is_nil() in libstand.
- Add a new 'boot' command to gpt(8) which makes a GPT disk bootable using
/boot/pmbr and /boot/gptboot. Note that the disk must have some free
space for the boot partition.
- This required exposing the backend of the 'add' function as a
gpt_add_part() function to the rest of gpt(8). 'boot' uses this to
create a boot partition if needed.
- Don't cripple cgbase() in the UFS boot code for /boot/gptboot so that
it can handle a filesystem > 1.5 TB.
- /boot/gptboot has a simple loader (gptldr) that doesn't do any I/O
unlike boot1 since /boot/pmbr loads all of gptboot up front. The
C portion of gptboot (gptboot.c) has been repocopied from boot2.c.
The primary changes are to parse the GPT to find a root filesystem
and to use 64-bit disk addresses. Currently gptboot assumes that the
first UFS partition on the disk is the / filesystem, but this algorithm
will likely be improved in the future.
- Teach the biosdisk driver in /boot/loader to understand GPT tables.
GPT partitions are identified as 'disk0pX:' (e.g. disk0p2:) which is
similar to the /dev names the kernel uses (e.g. /dev/ad0p2).
- Add a new "freebsd-boot" alias to g_part() for the new boot UUID.
MFC after: 1 month
Discussed with: marcel (some things might still change, but am committing
what I have so far)
o Introduce utf16_to_utf8().
o Add option -l to the show command to display the GPT label instead
of the friendly partition type.
o Add option -u to the show command to suppress the friendly output
and print th raw UUIDs instead.
starts at 1. No index is represented by 0.
o Change the show command to display the partition number at the expense
of the partition end columm. We already display the start and size.
o Enhance the add command to accept the -i option. The -i option allows
the user to specify which partition number the new partition should
get.
o Update the manpage accordingly.
While here:
o Make the UUIDs static to avoid runtime initialization,
o Rename ext to mslinux,
o Replace the use of memcmp() with uuid_equal(),
o Various style(9) improvements,
o Order the comparisons based on importance,
o Remove the word partition from all the descriptions,
o Other description improvements.
Includes patch from: T. Muthu Mohan < Muthu_T at dell dot com >
a PMBR. Make sure the create command creates a PMBR as well
(if not already present).
o When parsing the MBR, explicitly check for a PMBR and create
a PMBR map node if one is found.
o When parsing the MBR, recurse to handle extended partitions.
This allows us to flatten nested MBRs when migrating to a
GPT.
o Have the migrate command bail out if it encounters a partition
it doesn't know how to migrate. This avoids data loss.
o Change the output of the show command so that the UUIDs of the
GPT partitions fit on the same line.
o Show when partitions are extended partitions and add the PMBR
type.
Approved by: re (blanket)
<sys/gpt.h>. This avoids having to include both <sys/uuid.h> and
<uuid.h>, which is considered by your friendly committer to be
aestheticly displeasing (= ballyhoo barf barf :-)
o Use DCE compliant UUID functions and provide local
implementations if they don't exist,
o Move dumping of the map to show.c and print the
partition type,
o Some cleanups and rearrangements.
The default GPT partition type is UFS. When no starting block
or size are specified, the tool will create a partition in the
first free space it find (or that fits, depending on the size).
but is useful to have handy. EFI GPT partitions are used instead of the
fdisk+disklabel combination. They are pure 64 bit LBA, are fully
extensible, support up to 16383 partitons per disk, etc.
