block: vhdx - minor comments and typo correction.

Just a couple of minor comments to help note where allocated
buffers are freed, and a typo fix.

Signed-off-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
block: vhdx - add header update capability.

This adds the ability to update the headers in a VHDX image, including
generating a new MS-compatible GUID.

As VHDX depends on uuid.h, VHDX is now a configurable build option.  If
VHDX support is enabled, that will also enable uuid as well.  The
default is to have VHDX enabled.

To enable/disable VHDX:  --enable-vhdx, --disable-vhdx

Signed-off-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
block: vhdx code movement - VHDXMetadataEntries and BDRVVHDXState to header.

In preparation for VHDX log support, move these structures to the
header.

Signed-off-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
block: vhdx - log support struct and defines

This adds some magic number defines, and internal structure definitions
for VHDX log replay support.  The struct VHDXLogEntries does not reflect
an on-disk data structure, and thus does not need to be packed.

Some minor code style fixes are applied as well.

Signed-off-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
block: vhdx - break endian translation functions out

This moves the endian translation functions out from the vhdx.c source,
into a separate source file. In addition to the previously defined
endian functions, new endian translation functions for log support are
added as well.

Signed-off-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
block: vhdx - update log guid in header, and first write tracker

Allow tracking of first file write in the VHDX image, as well as
the ability to update the GUID in the header.  This is in preparation
for log support.

Signed-off-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
block: vhdx code movement - move vhdx_close() above vhdx_open()

Signed-off-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
block: vhdx - log parsing, replay, and flush support

This adds support for VHDX v0 logs, as specified in Microsoft's
VHDX Specification Format v1.00:
https://www.microsoft.com/en-us/download/details.aspx?id=34750

The following support is added:

* Log parsing, and validation - validate that an existing log
  is correct.

* Log search - search through an existing log, to find any valid
  sequence of entries.

* Log replay and flush - replay an existing log, and flush/clear
  the log when complete.

The VHDX log is a circular buffer, with elements (sectors) of 4KB.

A log entry is a variably-length number of sectors, that is
comprised of a header and 'descriptors', that describe each sector.

A log may contain multiple entries, know as a log sequence.  In a log
sequence, each log entry immediately follows the previous entry, with an
incrementing sequence number.  There can only ever be one active and
valid sequence in the log.

Each log entry must match the file log GUID in order to be valid (along
with other criteria).  Once we have flushed all valid log entries, we
marked the file log GUID to be zero, which indicates a buffer with no
valid entries.

Signed-off-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
block: vhdx - add region overlap detection for image files

Regions in the image file cannot overlap - the log, region tables,
and metdata must all be unique and non-overlapping.

This adds region checking by means of a QLIST; there can be a variable
number of regions and metadata (there may be metadata or region tables
that we do not recognize / know about, but are not required).

This adds the capability to register a region for later checking, and
to check against registered regions for any overlap.

Also, if neither the BAT or Metadata region tables are found, return
error.

Signed-off-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
block: vhdx - add log write support

This adds support for writing to the VHDX log.

For spec details, see VHDX Specification Format v1.00:
https://www.microsoft.com/en-us/download/details.aspx?id=34750

There are a few limitations to this log support:
1.) There is no caching yet
2.) The log is flushed after each entry

The primary write interface, vhdx_log_write_and_flush(), performs a log
write followed by an immediate flush of the log.

As each log entry sector is a minimum of 4KB, partial sector writes are
filled in with data from the disk write destination.

If the current file log GUID is 0, a new GUID is generated and updated
in the header.

Signed-off-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
block: vhdx write support

This adds support for writing to VHDX image files, using coroutines.
Writes into the BAT table goes through the VHDX log.  Currently, BAT
table writes occur when expanding a dynamic VHDX file, and allocating a
new BAT entry.

Signed-off-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
block: vhdx - remove BAT file offset bit shifting

Bit shifting can be fun, but in this case it was unnecessary.  The
upper 44 bits of the 64-bit BAT entry is specifies the File Offset,
so we shifted the bits to get access to the value.

However, per the spec the value is in MB.  So we dutifully shifted back
to the left by 20 bits, to convert to a true uint64_t file offset.

This replaces those steps with just a bit mask, to get rid of the lower
20 bits instead.

Signed-off-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
block: vhdx - move more endian translations to vhdx-endian.c

In preparation for vhdx_create(), move more endian translation
functions out to vhdx-endian.c.

Signed-off-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
block: vhdx - break out code operations to functions

This is preperation for vhdx_create().  The ability to write headers,
and calculate the number of BAT entries will be needed within the
create() functions, so move this relevant code into helper functions.

Signed-off-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
block: vhdx - fix comment typos in header, fix incorrect struct fields

VHDXPage83Data and VHDXParentLocatorHeader both incorrectly had their
MSGUID fields set as arrays of 16.  This is incorrect (it stems from
an early version where those fields were uint_8 arrays).  Those fields
were, up to this patch, unused.

Also, there were a couple of typos and incorrect wording in comments,
and those have been fixed up as well.

Signed-off-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
block: vhdx - add .bdrv_create() support

This adds support for VHDX image creation, for images of type "Fixed"
and "Dynamic".  "Differencing" types (i.e., VHDX images with backing
files) are currently not supported.

Options for image creation include:
    * log size:
        The size of the journaling log for VHDX.  Minimum is 1MB,
        and it must be a multiple of 1MB. Invalid log sizes will be
        silently fixed by rounding up to the nearest MB.

        Default is 1MB.

    * block size:
        This is the size of a payload block.  The range is 1MB to 256MB,
        inclusive, and must be a multiple of 1MB as well.  Invalid sizes
        and multiples will be silently fixed.  If '0' is passed, then
        a sane size is chosen (depending on virtual image size).

        Default is 0 (Auto-select).

    * subformat:
        - "dynamic"
            An image without data pre-allocated.
        - "fixed"
            An image with data pre-allocated.

        Default is "dynamic"

When creating the image file, the lettered sections are created:

-----------------------------------------------------------------.
|   (A)    |   (B)    |    (C)    |     (D)       |     (E)
|  File ID |  Header1 |  Header 2 |  Region Tbl 1 |  Region Tbl 2
|          |          |           |               |
.-----------------------------------------------------------------.
0         64KB      128KB       192KB           256KB          320KB

.---- ~ ----------- ~ ------------ ~ ---------------- ~ -----------.
|     (F)     |     (G)       |    (H)    |
| Journal Log |  BAT / Bitmap |  Metadata |  .... data ......
|             |               |           |
.---- ~ ----------- ~ ------------ ~ ---------------- ~ -----------.
1MB         (var.)          (var.)      (var.)

Signed-off-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
block: vhdx - update _make_test_img() to filter out vhdx options

The non-global option output is suppresed in _make_test_img() for
output verification in the 0?? tests.  This adds suppression for
the vhdx-unique options as well.  This allows check -vhdx to run
successfully.

Signed-off-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
block: qemu-iotests for vhdx, add write test support

This removes the IMGFMT_GENERIC blocker for read-only, so existing
iotests run read/write tests for vhdx images created by qemu-img (e.g.
tests 001, 002, 003).

In addition, this updates the sample image test for the Hyper-V
created image, to verify we can write it as well.

Signed-off-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
block: vhdx qemu-iotest - log replay of data sector

This tests the replay of a data sector in a VHDX image file.

The image file is a 10G dynamic image, with 4MB block size.  The
image was created with qemu-img, and the log left unplayed by
modification of the vhdx image format driver.

It was verified under both QEMU and Hyper-V that the image file,
post log replay, matched.

Signed-off-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>