Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

MFC r265318:
For schemes that do an automatic partition aligning move this code to
separate function.

MFC r265331:
Prevent an unexpected shrinking on resizing due to alignment for MBR,
PC98 and VTOC8 schemes.

MFC r265333:
Add better error description for case when we are doing resize and
scheme-specific method returns EBUSY.

MFC r265539:
It is safe to allow shrinking, when aligned size is bigger than current.

MFC r251587 (by marcel):
Remove stub implementation.

MFC r251588 (by marcel):
Change the set and unset ctlreqs by making the index argument optional.
This allows setting attributes on tables. One simply does not provide
an index in that case. Otherwise the entry corresponding the index has
the attribute set or unset.

Use this change to fix a relatively longstanding bug in our GPT scheme
that's the result of rev 198097 (relatively harmless) followed by rev
237057 (damaging). The damaging part being that our GPT scheme always
has the active flag set on the PMBR slice. This is in violation with
EFI. Existing EFI implementions for both x86 and ia64 reject the GPT.
As such, GPT disks created by us aren't usable under EFI because of
that.

After this change, GPT disks never have the active flag set on the PMBR
slice. In order to make the GPT disk bootable under some x86 BIOSes,
the reason of rev 198097, one must now set the active attribute on the
gpt table. The kernel will apply this to the PMBR slice For (S)ATA:
gpart set -a active ada0

To fix an existing GPT disk that has the active flag set in the PMBR,
and that does not need the flag, use (again for (S)ATA):
gpart unset -a active ada0

The EBR, MBR & PC98 schemes, which also impement at least 1 attribute,
now check to make sure the entry passed is valid. They do not have
attributes that apply to the table.

Merge r247961 from head:
Support the FAT16 partition type in gpart(8)

PR: kern/174714
Submitted by: 4721 at hushmail dot com

MFC r234417:

VMware environments are not unusual now. Add VMware partitions recognition
(both MBR for ESXi <= 4.1 and GPT for ESXi 5) to g_part.

Reviewed by: ae
Approved by: ae

MFC r231754:
Add additional check to EBR probe and create methods:
don't try probe and create EBR scheme when parent partition type
is not "ebr". This fixes error messages about corrupted EBR for
some partitions where is actually another partition scheme.

NOTE: if you have EBR on the partition with different than "ebr"
(0x05) type, then you will lost access to partitions until it will be
changed.

MFC r231928:
Add alias for the partition type 0x0f. Now "ebr" name is used for both
types 0x05 and 0x0f, but 0x05 is preferred and used when partition is
created with "gpart add -t ebr ...".
This should keep EBR partitions accessible after r231754 for those,
who have EBR on the partition with type 0x0f.

MFC r231367:
Add alias for the partition with type 0x42 to the MBR scheme.

MFC r230064:

Allow an MBR primary or extended Linux swap partition to be specified
as the system dump device. This was already allowed for GPT. The Linux
swap metadata at the beginning of the partition should not be disturbed
because the crash dump is written at the end.

Reviewed by: alfred, pjd, marcel

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

MS Windows NT+ uses 4 bytes at offset 0x1b8 in the MBR to identify
disk drive. The boot0cfg(8) utility preserves these 4 bytes when is
writing bootcode to keep a multiboot ability.
Change gpart's bootcode method to keep DSN if it is not zero. Also
do not allow writing bootcode with size not equal to MBRSIZE.

PR: kern/157819
Tested by: Eir Nym
MFC after: 1 month

Some partitioning tools may have a different opinion about disk
geometry and partitions may start from withing the first track.
If we found such partitions, then do not reserve space of the
first track, only first sector.

Do not truncate available disk space to the closest track boundary.

Remove unused variable.

MFC after: 1 week

Replace UINT_MAX to UINT32_MAX.

Pointed out by: kib
MFC after: 1 week

Limit number of sectors that can be addressed.

MFC after: 1 week

Add some FEATURE macros for various GEOM classes.

No FreeBSD version bump, the userland application to query the features will
be committed last and can serve as an indication of the availablility if
needed.

Sponsored by: Google Summer of Code 2010
Submitted by: kibab
Reviewed by: silence on geom@ during 2 weeks
X-MFC after: to be determined in last commit with code from this project

Add new user-friendly aliases for partition types for the MBR and
EBR schemes: fat32, ebr, linux-data, linux-raid, linux-swap and
linux-lvm. Add bios-boot GUID and alias for the GPT scheme. It used by
GRUB 2 loader. Also do sorting definitions of types in diskmbr.h
and in g_part.c.

PR: bin/120990, kern/147664
MFC after: 2 weeks

Don't warn if a partition appears not to be aligned on a track boundary.
Modern disks use LBA and create a fake CHS geometry that doesn't have any
relation to the on-disk layout of data.

The canonical way to print __func__ when using KASSERT() is to write
("%s", __func__). This avoids clang's -Wformat-string warnings.

Some schemes can allocate memory for internal purposes but when
GEOM does withering this memory doesn't freed. Add G_PART_DESTROY
call to g_part_wither. Also add missed g_free() call to G_PART_READ
method for MBR and PC98 schemes.

Submitted by: jh (previous version)
Reviewed by: pjd
Approved by: kib (mentor)

Add NTFS partition type to GEOM_MBR.

Implement the resize verb and add support for resizing partitions
for all schemes but EBR. Quality work by Andrey!

Submitted by: "Andrey V. Elsukov" <bu7cher@yandex.ru>

Sharpen the saw:
o MBR uses 32-bit block numbers. Limit the scheme to 2^32-1
blocks when the media is larger.

Add the EBR scheme. The EBR scheme supports the Extended Boot Records
found inside extended partitions and used to create logical partitions.
At this time write/modify support is not (yet) present.
The EBR and MBR schemes both check the parent scheme. The MBR will
back-off when nested under another MBR, whereas the EBR only nests
under a MBR.

Fix g_part_*dumpconf to return void to match kobj definition.
Fix g_part_*name to return a const char * rather than a char *.

Allow boot code to be smaller than what the scheme expects.
This effectively changes the boot code size to be an upper
bound and makes the interface more flexible.

Add the set and unset verbs used to set and clear attributes for
partition entries. Implement the setunset method for the MBR
scheme to control the active flag.

Add the raw partition type to the XML.

Implement the G_PART_DUMPCONF method for all 6 schemes. Also call
the method for the (indent == NULL) case (i.e. the kern.geom.conftxt
sysctl). The purpose is to extend the conftxt output with scheme-
specific fields which can be used by libdisk. In particular, have
the schemes dump the xs and xt fields, which contain the backward
compatible values for class type and partition type. This allows
libdisk to work with the legacy slicers as well as with gpart and
helps/promotes migration.

Add the bootcode verb for installing boot code. Boot code
is supported for the MBR, GPT and PC98 schemes, where GPT
installs boot code into the PMBR.

Redefine G_PART_SCHEME_DECLARE() from populating a private linker set
to declaring a proper module. The module event handler is part of the
gpart core and will add the scheme to an internal list on module load
and will remove the scheme from the internal list on module unload.
This makes it possible to dynamically load and unload partitioning
schemes.

Follow-up improvements to the handling of false positives: If the
partition table is empty, check to see if we have something that
looks sufficiently like a BPB. On non-i386 machines, the boot
sector typically doesn't contain boot code; the end of the boot
sector is all zeroes. This is also where the partition table is
for MBRs.
We only check the sector size and cluster size, as that seems to
be the most reliable across implementations, BPB versions and
platforms.

Better handle false positives. The MBR differs from the boot sector
only because there's a partition table where the boot sector has
boot code. Boot sectors without boot code look like a MBR for all
practical purposes. This change adds a check for the partition table
and fails the probe when it's obvously invalid. The assumption being
that the sector contains a boot sector and not a MBR.
More checks are needed to distinguish a boot secto without boot code
from a (empty) MBR.

Have gpart synthesize a disk geometry if the underlying provider
don't have it. Some partitioning schemes, as well as file systems,
operate on the geometry and without it such schemes (e.g. MBR)
and file systems (e.g. FAT) can't be created. This is useful for
memory disks.

Add the MBR partitioning scheme to g_part. This does not yet
support the ability to install boot code.