Instead of requiring separate input/output buffers for
encrypting data, change qcow2_encrypt_sectors() to assume
use of a single buffer, encrypting in place. The current
callers all used the same buffer for input/output already.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>
Message-id: 20170623162419.26068-11-berrange@redhat.com
Reviewed-by: NAlberto Garcia <berto@igalia.com>
Signed-off-by: NMax Reitz <mreitz@redhat.com>

This converts the qcow driver to make use of the QCryptoBlock
APIs for encrypting image content. This is only wired up to
permit use of the legacy QCow encryption format. Users who wish
to have the strong LUKS format should switch to qcow2 instead.

With this change it is now required to use the QCryptoSecret
object for providing passwords, instead of the current block
password APIs / interactive prompting.

  $QEMU \
    -object secret,id=sec0,file=/home/berrange/encrypted.pw \
    -drive file=/home/berrange/encrypted.qcow,encrypt.format=aes,\
           encrypt.key-secret=sec0

Though note that running QEMU system emulators with the AES
encryption is no longer supported, so while the above syntax
is valid, QEMU will refuse to actually run the VM in this
particular example.

Likewise when creating images with the legacy AES-CBC format

  qemu-img create -f qcow \
    --object secret,id=sec0,file=/home/berrange/encrypted.pw \
    -o encrypt.format=aes,encrypt.key-secret=sec0 \
    /home/berrange/encrypted.qcow 64M
Reviewed-by: NMax Reitz <mreitz@redhat.com>
Reviewed-by: NAlberto Garcia <berto@igalia.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>
Message-id: 20170623162419.26068-10-berrange@redhat.com
Signed-off-by: NMax Reitz <mreitz@redhat.com>

Instead of requiring separate input/output buffers for
encrypting data, change encrypt_sectors() to assume
use of a single buffer, encrypting in place. One current
caller uses the same buffer for input/output already
and the other two callers are easily converted to do so.
Reviewed-by: NAlberto Garcia <berto@igalia.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NMax Reitz <mreitz@redhat.com>
Reviewed-by: NKevin Wolf <kwolf@redhat.com>
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>
Message-id: 20170623162419.26068-9-berrange@redhat.com
Signed-off-by: NMax Reitz <mreitz@redhat.com>

Historically the qcow & qcow2 image formats supported a property
"encryption=on" to enable their built-in AES encryption. We'll
soon be supporting LUKS for qcow2, so need a more general purpose
way to enable encryption, with a choice of formats.

This introduces an "encrypt.format" option, which will later be
joined by a number of other "encrypt.XXX" options. The use of
a "encrypt." prefix instead of "encrypt-" is done to facilitate
mapping to a nested QAPI schema at later date.

e.g. the preferred syntax is now

  qemu-img create -f qcow2 -o encrypt.format=aes demo.qcow2
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>
Message-id: 20170623162419.26068-8-berrange@redhat.com
Reviewed-by: NAlberto Garcia <berto@igalia.com>
Signed-off-by: NMax Reitz <mreitz@redhat.com>

Test 048 is designed to verify data preservation during an
image resize. The qcow (v1) format impl has never supported
resize so always fails.
Reviewed-by: NMax Reitz <mreitz@redhat.com>
Reviewed-by: NAlberto Garcia <berto@igalia.com>
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>
Message-id: 20170623162419.26068-7-berrange@redhat.com
Signed-off-by: NMax Reitz <mreitz@redhat.com>

Test 042 is designed to verify operation with zero sized images.
Such images are not supported with qcow (v1), so this test has
always failed.
Reviewed-by: NMax Reitz <mreitz@redhat.com>
Reviewed-by: NAlberto Garcia <berto@igalia.com>
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>
Message-id: 20170623162419.26068-6-berrange@redhat.com
Signed-off-by: NMax Reitz <mreitz@redhat.com>

The qcow driver refuses to open images which are less than
2 bytes in size, but will happily create such images. Add
a check in the create path to avoid this discrepancy.
Reviewed-by: NMax Reitz <mreitz@redhat.com>
Reviewed-by: NAlberto Garcia <berto@igalia.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>
Message-id: 20170623162419.26068-5-berrange@redhat.com
Signed-off-by: NMax Reitz <mreitz@redhat.com>

Document that use of guest virtual sector numbers as the basis for
the initialization vectors is a potential weakness, when combined
with internal snapshots or multiple images using the same passphrase.
This fixes the formatting of the itemized list too.
Reviewed-by: NMax Reitz <mreitz@redhat.com>
Reviewed-by: NAlberto Garcia <berto@igalia.com>
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>
Message-id: 20170623162419.26068-4-berrange@redhat.com
Signed-off-by: NMax Reitz <mreitz@redhat.com>

When integrating the crypto support with qcow/qcow2, we don't
want to use the bare LUKS option names "hash-alg", "key-secret",
etc. We need to namespace them to match the nested QAPI schema.

e.g. "encrypt.hash-alg", "encrypt.key-secret"

so that they don't clash with any general qcow options at a later
date.
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NMax Reitz <mreitz@redhat.com>
Reviewed-by: NAlberto Garcia <berto@igalia.com>
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>
Message-id: 20170623162419.26068-3-berrange@redhat.com
Signed-off-by: NMax Reitz <mreitz@redhat.com>

The block/crypto.c defines a set of QemuOpts that provide
parameters for encryption. This will also be needed by
the qcow/qcow2 integration, so expose the relevant pieces
in a new block/crypto.h header. Some helper methods taking
QemuOpts are changed to take QDict to simplify usage in
other places.
Reviewed-by: NMax Reitz <mreitz@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NAlberto Garcia <berto@igalia.com>
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>
Message-id: 20170623162419.26068-2-berrange@redhat.com
Signed-off-by: NMax Reitz <mreitz@redhat.com>

VFIO fixes 2017-07-10

 - Don't iterate over non-realized devices (Alex Williamson)
 - Add PCIe capability version fixup (Alex Williamson)

# gpg: Signature made Mon 10 Jul 2017 20:06:11 BST
# gpg:                using RSA key 0x239B9B6E3BB08B22
# gpg: Good signature from "Alex Williamson <alex.williamson@redhat.com>"
# gpg:                 aka "Alex Williamson <alex@shazbot.org>"
# gpg:                 aka "Alex Williamson <alwillia@redhat.com>"
# gpg:                 aka "Alex Williamson <alex.l.williamson@gmail.com>"
# Primary key fingerprint: 42F6 C04E 540B D1A9 9E7B  8A90 239B 9B6E 3BB0 8B22

* remotes/awilliam/tags/vfio-updates-20170710.0:
  vfio/pci: Fixup v0 PCIe capabilities
  vfio: Test realized when using VFIOGroup.device_list iterator
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

While ARM could present the xenpv machine, it does not and trying to enable
it breaks compilation.  Revert to the previous test which only looked at
$target_name, not $cpu.

Fixes: 3b6b7550Reported-by: NAlex Bennée <alex.bennee@linaro.org>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Message-id: 20170711100049.20513-1-pbonzini@redhat.com
Reviewed-by: NPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

Migration pull 2017-07-10

# gpg: Signature made Mon 10 Jul 2017 18:04:57 BST
# gpg:                using RSA key 0x0516331EBC5BFDE7
# gpg: Good signature from "Dr. David Alan Gilbert (RH2) <dgilbert@redhat.com>"
# gpg: WARNING: This key is not certified with a trusted signature!
# gpg:          There is no indication that the signature belongs to the owner.
# Primary key fingerprint: 45F5 C71B 4A0C B7FB 977A  9FA9 0516 331E BC5B FDE7

* remotes/dgilbert/tags/pull-migration-20170710a:
  migration: Make compression_threads use save/load_setup/cleanup()
  migration: Convert ram to use new load_setup()/load_cleanup()
  migration: Create load_setup()/cleanup() methods
  migration: Rename cleanup() to save_cleanup()
  migration: Rename save_live_setup() to save_setup()
  doc: update TYPE_MIGRATION documents
  doc: add item for "-M enforce-config-section"
  vl: move global property, migrate init earlier
  migration: fix handling for --only-migratable
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

Once there, be consistent and use
compress_thread_{save,load}_{setup,cleanup}.
Signed-off-by: NJuan Quintela <quintela@redhat.com>
Reviewed-by: NDr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <20170628095228.4661-6-quintela@redhat.com>
Signed-off-by: NDr. David Alan Gilbert <dgilbert@redhat.com>

Once there, I rename ram_migration_cleanup() to ram_save_cleanup().
Notice that this is the first pass, and I only passed XBZRLE to the
new scheme.  Moved decoded_buf to inside XBZRLE struct.
As a bonus, I don't have to export xbzrle functions from ram.c.
Signed-off-by: NJuan Quintela <quintela@redhat.com>
Reviewed-by: NDr. David Alan Gilbert <dgilbert@redhat.com>

--

loaded_data pointer was needed because called can change it (dave)
spell loaded correctly in comment (dave)
Message-Id: <20170628095228.4661-5-quintela@redhat.com>
Signed-off-by: NDr. David Alan Gilbert <dgilbert@redhat.com>

We need to do things at load time and at cleanup time.
Signed-off-by: NJuan Quintela <quintela@redhat.com>

--

Move the printing of the error message so we can print the device
giving the error.
Add call to postcopy stuff
Message-Id: <20170628095228.4661-4-quintela@redhat.com>
Reviewed-by: NDr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: NDr. David Alan Gilbert <dgilbert@redhat.com>

We need a cleanup for loads, so we rename here to be consistent.
Signed-off-by: NJuan Quintela <quintela@redhat.com>
Reviewed-by: NDr. David Alan Gilbert <dgilbert@redhat.com>

--

Rename htab_cleanup to htap_save_cleanup as dave suggestion
Message-Id: <20170628095228.4661-3-quintela@redhat.com>
Signed-off-by: NDr. David Alan Gilbert <dgilbert@redhat.com>

We are going to use it now for more than save live regions.
Once there rename qemu_savevm_state_begin() to qemu_savevm_state_setup().
Signed-off-by: NJuan Quintela <quintela@redhat.com>
Reviewed-by: NDr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <20170628095228.4661-2-quintela@redhat.com>
Signed-off-by: NDr. David Alan Gilbert <dgilbert@redhat.com>

[Peter collected Eduardo's patch comment and formatted into patch]
Suggested-by: NEduardo Habkost <ehabkost@redhat.com>
Signed-off-by: NPeter Xu <peterx@redhat.com>
Message-Id: <1499242883-2184-5-git-send-email-peterx@redhat.com>
Reviewed-by: NEduardo Habkost <ehabkost@redhat.com>
Signed-off-by: NDr. David Alan Gilbert <dgilbert@redhat.com>

It's never documented, and now we have one more parameter for it (which
obsoletes this one). Document it properly.
Suggested-by: NEduardo Habkost <ehabkost@redhat.com>
Signed-off-by: NPeter Xu <peterx@redhat.com>
Message-Id: <1499396048-21657-1-git-send-email-peterx@redhat.com>
Reviewed-by: NGreg Kurz <groug@kaod.org>
Reviewed-by: NEduardo Habkost <ehabkost@redhat.com>
Signed-off-by: NDr. David Alan Gilbert <dgilbert@redhat.com>
  Removed 'Although now' commit message as per Eduardo's review

Currently drive_init_func() may call migrate_get_current() while the
migrate object is still not ready yet at that time. Move the migration
object init earlier, along with the global properties, right after
acceleration init.

This fixes a breakage for iotest 055, which caused an assertion failure.
Reported-by: NMax Reitz <mreitz@redhat.com>
Reported-by: NPhilippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: NEduardo Habkost <ehabkost@redhat.com>
Tested-by: NQingFeng Hao <haoqf@linux.vnet.ibm.com>
Fixes: 3df663 ("migration: move only_migratable to MigrationState")
Signed-off-by: NPeter Xu <peterx@redhat.com>
Message-Id: <1499242883-2184-3-git-send-email-peterx@redhat.com>
Signed-off-by: NDr. David Alan Gilbert <dgilbert@redhat.com>

MigrateState object is not ready at that time, so we'll get an
assertion. Use qemu_global_option() instead.
Reported-by: NEduardo Habkost <ehabkost@redhat.com>
Suggested-by: NEduardo Habkost <ehabkost@redhat.com>
Reviewed-by: NEduardo Habkost <ehabkost@redhat.com>
Reviewed-by: NJuan Quintela <quintela@redhat.com>
Fixes: 3df663e5 ("migration: move only_migratable to MigrationState")
Signed-off-by: NPeter Xu <peterx@redhat.com>
Message-Id: <1499242883-2184-2-git-send-email-peterx@redhat.com>
Signed-off-by: NDr. David Alan Gilbert <dgilbert@redhat.com>

Intel 82599 VFs report a PCIe capability version of 0, which is
invalid.  The earliest version of the PCIe spec used version 1.  This
causes Windows to fail startup on the device and it will be disabled
with error code 10.  Our choices are either to drop the PCIe cap on
such devices, which has the side effect of likely preventing the guest
from discovering any extended capabilities, or performing a fixup to
update the capability to the earliest valid version.  This implements
the latter.
Signed-off-by: NAlex Williamson <alex.williamson@redhat.com>

VFIOGroup.device_list is effectively our reference tracking mechanism
such that we can teardown a group when all of the device references
are removed.  However, we also use this list from our machine reset
handler for processing resets that affect multiple devices.  Generally
device removals are fully processed (exitfn + finalize) when this
reset handler is invoked, however if the removal is triggered via
another reset handler (piix4_reset->acpi_pcihp_reset) then the device
exitfn may run, but not finalize.  In this case we hit asserts when
we start trying to access PCI helpers since much of the PCI state of
the device is released.  To resolve this, add a pointer to the Object
DeviceState in our common base-device and skip non-realized devices
as we iterate.
Signed-off-by: NAlex Williamson <alex.williamson@redhat.com>

nbd patches for 2017-07-10

- Eric Blake: MAINTAINERS: Promote NBD to supported, with new maintainer
- Vladimir Sementsov-Ogievskiy: [00/10] nbd refactoring part 2

# gpg: Signature made Mon 10 Jul 2017 15:59:18 BST
# gpg:                using RSA key 0xA7A16B4A2527436A
# gpg: Good signature from "Eric Blake <eblake@redhat.com>"
# gpg:                 aka "Eric Blake (Free Software Programmer) <ebb9@byu.net>"
# gpg:                 aka "[jpeg image of size 6874]"
# Primary key fingerprint: 71C2 CC22 B1C4 6029 27D2  F3AA A7A1 6B4A 2527 436A

* remotes/ericb/tags/pull-nbd-2017-07-10-v2:
  nbd: use generic trace subsystem instead of TRACE macro
  nbd: refactor tracing
  nbd/server: rename clientflags var in nbd_negotiate_options
  nbd/server: fix TRACE in nbd_negotiate_send_rep_len
  nbd/client: refactor TRACE of NBD_MAGIC
  nbd/common: nbd_tls_handshake: remove extra TRACE
  nbd/server: add errp to nbd_send_reply()
  nbd/server: use errp instead of LOG
  nbd/server: refactor nbd_negotiate
  nbd/server: nbd_negotiate: return 1 on NBD_OPT_ABORT
  MAINTAINERS: Promote NBD to supported, with new maintainer
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

Let NBD use the trace mechanisms already present in qemu. Now you can
use the -trace optino of qemu, or the -T/--trace option of qemu-img,
qemu-io, and qemu-nbd, to select nbd traces. For qemu, the QMP commands
trace-event-{get,set}-state can also toggle tracing on the fly.

Example:
   qemu-nbd --trace 'nbd_*' <image file> # enables all nbd traces

Recompilation with CFLAGS=-DDEBUG_NBD is no more needed, furthermore,
DEBUG_NBD macro is removed from the code.
Signed-off-by: NVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20170707152918.23086-11-vsementsov@virtuozzo.com>
[eblake: minor tweaks to a couple of traces]
Signed-off-by: NEric Blake <eblake@redhat.com>

Reorganize traces: move, reword, add information, drop extra ones.
Signed-off-by: NVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20170707152918.23086-10-vsementsov@virtuozzo.com>
Signed-off-by: NEric Blake <eblake@redhat.com>

Rename 'clientflags' to just 'option'. This variable has nothing to do
with flags, but is a single integer representing the option requested
by the client.
Signed-off-by: NVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20170707152918.23086-9-vsementsov@virtuozzo.com>
Signed-off-by: NEric Blake <eblake@redhat.com>

Fix wrong order of TRACE arguments.
Signed-off-by: NVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20170707152918.23086-8-vsementsov@virtuozzo.com>
Signed-off-by: NEric Blake <eblake@redhat.com>

We are going to switch from TRACE macro to trace points,
this TRACE complicates things, this patch simplifies it.
Signed-off-by: NVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20170707152918.23086-7-vsementsov@virtuozzo.com>
Signed-off-by: NEric Blake <eblake@redhat.com>

Error is propagated to the caller, TRACE is not needed.
Signed-off-by: NVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Message-Id: <20170707152918.23086-6-vsementsov@virtuozzo.com>
Signed-off-by: NEric Blake <eblake@redhat.com>

Signed-off-by: NVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Message-Id: <20170707152918.23086-5-vsementsov@virtuozzo.com>
Signed-off-by: NEric Blake <eblake@redhat.com>

Move to modern errp scheme from just LOGging errors.
Signed-off-by: NVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20170707152918.23086-4-vsementsov@virtuozzo.com>
Signed-off-by: NEric Blake <eblake@redhat.com>

Combine two successive "if (oldStyle) {...} else {...}" into one.

Block "if (client->tlscreds)" under "if (oldStyle)" is unreachable,
as we have "oldStyle = client->exp != NULL && !client->tlscreds;".
So, delete this block.
Signed-off-by: NVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20170707152918.23086-3-vsementsov@virtuozzo.com>
Signed-off-by: NEric Blake <eblake@redhat.com>

Separate the case when a client sends NBD_OPT_ABORT from all other
errors. It will be needed for the following patch, where errors will be
reported.
This particular case is not actually an error - it honestly follows the
NBD protocol. Therefore it should not be reported like an error.
Signed-off-by: NVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Message-Id: <20170707152918.23086-2-vsementsov@virtuozzo.com>
Signed-off-by: NEric Blake <eblake@redhat.com>

We are promising more than just odd fixes, and Paolo is hoping
to offload the pull requests to me.  Also, enough of NBD is related
to the block layer that it is worth including qemu-block on patches.

While at it, include blockdev-nbd.c and qemu-nbd.texi in the set
of maintained files.
Signed-off-by: NEric Blake <eblake@redhat.com>
Message-Id: <20170707182151.29872-1-eblake@redhat.com>
Acked-by: NPaolo Bonzini <pbonzini@redhat.com>

Block layer patches

# gpg: Signature made Mon 10 Jul 2017 12:26:44 BST
# gpg:                using RSA key 0x7F09B272C88F2FD6
# gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>"
# Primary key fingerprint: DC3D EB15 9A9A F95D 3D74  56FE 7F09 B272 C88F 2FD6

* remotes/kevin/tags/for-upstream: (40 commits)
  block: Make bdrv_is_allocated_above() byte-based
  block: Minimize raw use of bds->total_sectors
  block: Make bdrv_is_allocated() byte-based
  backup: Switch backup_run() to byte-based
  backup: Switch backup_do_cow() to byte-based
  backup: Switch block_backup.h to byte-based
  backup: Switch BackupBlockJob to byte-based
  block: Drop unused bdrv_round_sectors_to_clusters()
  mirror: Switch mirror_iteration() to byte-based
  mirror: Switch mirror_do_read() to byte-based
  mirror: Switch mirror_cow_align() to byte-based
  mirror: Update signature of mirror_clip_sectors()
  mirror: Switch mirror_do_zero_or_discard() to byte-based
  mirror: Switch MirrorBlockJob to byte-based
  commit: Switch commit_run() to byte-based
  commit: Switch commit_populate() to byte-based
  stream: Switch stream_run() to byte-based
  stream: Drop reached_end for stream_complete()
  stream: Switch stream_populate() to byte-based
  trace: Show blockjob actions via bytes, not sectors
  ...
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

We are gradually moving away from sector-based interfaces, towards
byte-based.  In the common case, allocation is unlikely to ever use
values that are not naturally sector-aligned, but it is possible
that byte-based values will let us be more precise about allocation
at the end of an unaligned file that can do byte-based access.

Changing the signature of the function to use int64_t *pnum ensures
that the compiler enforces that all callers are updated.  For now,
the io.c layer still assert()s that all callers are sector-aligned,
but that can be relaxed when a later patch implements byte-based
block status.  Therefore, for the most part this patch is just the
addition of scaling at the callers followed by inverse scaling at
bdrv_is_allocated().  But some code, particularly stream_run(),
gets a lot simpler because it no longer has to mess with sectors.
Leave comments where we can further simplify by switching to
byte-based iterations, once later patches eliminate the need for
sector-aligned operations.

For ease of review, bdrv_is_allocated() was tackled separately.
Signed-off-by: NEric Blake <eblake@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

bdrv_is_allocated_above() was relying on intermediate->total_sectors,
which is a field that can have stale contents depending on the value
of intermediate->has_variable_length.  An audit shows that we are safe
(we were first calling through bdrv_co_get_block_status() which in
turn calls bdrv_nb_sectors() and therefore just refreshed the current
length), but it's nicer to favor our accessor functions to avoid having
to repeat such an audit, even if it means refresh_total_sectors() is
called more frequently.
Suggested-by: NJohn Snow <jsnow@redhat.com>
Signed-off-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NManos Pitsidianakis <el13635@mail.ntua.gr>
Reviewed-by: NJeff Cody <jcody@redhat.com>
Reviewed-by: NJohn Snow <jsnow@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

We are gradually moving away from sector-based interfaces, towards
byte-based.  In the common case, allocation is unlikely to ever use
values that are not naturally sector-aligned, but it is possible
that byte-based values will let us be more precise about allocation
at the end of an unaligned file that can do byte-based access.

Changing the signature of the function to use int64_t *pnum ensures
that the compiler enforces that all callers are updated.  For now,
the io.c layer still assert()s that all callers are sector-aligned
on input and that *pnum is sector-aligned on return to the caller,
but that can be relaxed when a later patch implements byte-based
block status.  Therefore, this code adds usages like
DIV_ROUND_UP(,BDRV_SECTOR_SIZE) to callers that still want aligned
values, where the call might reasonbly give non-aligned results
in the future; on the other hand, no rounding is needed for callers
that should just continue to work with byte alignment.

For the most part this patch is just the addition of scaling at the
callers followed by inverse scaling at bdrv_is_allocated().  But
some code, particularly bdrv_commit(), gets a lot simpler because it
no longer has to mess with sectors; also, it is now possible to pass
NULL if the caller does not care how much of the image is allocated
beyond the initial offset.  Leave comments where we can further
simplify once a later patch eliminates the need for sector-aligned
requests through bdrv_is_allocated().

For ease of review, bdrv_is_allocated_above() will be tackled
separately.
Signed-off-by: NEric Blake <eblake@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>