Commit Graph

1196 Commits

Author SHA1 Message Date
Hu Tao ac95acdb8e qcow2: use start_of_cluster() and offset_into_cluster() everywhere
Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-12-06 16:53:50 +01:00
Peter Lieven 7572ddc8db block/iscsi: set bs->bl.opt_transfer_length
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-12-05 11:45:24 +01:00
Peter Lieven 1c0704a556 block/iscsi: set bdi->cluster_size
this patch aims to set bdi->cluster_size to the internal page size
of the iscsi target so that enabled callers can align requests
properly.

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-12-05 11:45:24 +01:00
Wenchao Xia 8c116b0e41 qemu-nbd: support internal snapshot export
Now it is possible to directly export an internal snapshot, which
can be used to probe the snapshot's contents without qemu-img
convert.

Signed-off-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-12-04 15:19:00 +01:00
Wenchao Xia 7b4c4781e3 snapshot: distinguish id and name in load_tmp
Since later this function will be used so improve it. The only caller of it
now is qemu-img, and it is not impacted by introduce function
bdrv_snapshot_load_tmp_by_id_or_name() that call bdrv_snapshot_load_tmp()
twice to keep old search logic. bdrv_snapshot_load_tmp_by_id_or_name() return
int to let caller know the errno, and errno will be used later.
Also fix a typo in comments of bdrv_snapshot_delete().

Signed-off-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-12-04 15:19:00 +01:00
Kevin Wolf f8413b3c23 qcow2: Zero-initialise first cluster for new images
Strictly speaking, this is only required for has_zero_init() == false,
but it's easy enough to just do a cluster-aligned write that is padded
with zeros after the header.

This fixes that after 'qemu-img create' header extensions are attempted
to be parsed that are really just random leftover data.

Cc: qemu-stable@nongnu.org
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-12-04 11:29:37 +01:00
Paolo Bonzini 97a2ae3453 raw-posix: add support for write_zeroes on XFS and block devices
The code is similar to the implementation of discard and write_zeroes
with UNMAP.  However, failure must be propagated up to block.c.

The stale page cache problem can be reproduced as follows:

    # modprobe scsi-debug lbpws=1 lbprz=1
    # ./qemu-io /dev/sdXX
    qemu-io> write -P 0xcc 0 2M
    qemu-io> write -z 0 1M
    qemu-io> read -P 0x00 0 512
    Pattern verification failed at offset 0, 512 bytes
    qemu-io> read -v 0 512
    00000000:  cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc  ................
    ...

    # ./qemu-io --cache=none /dev/sdXX
    qemu-io> write -P 0xcc 0 2M
    qemu-io> write -z 0 1M
    qemu-io> read -P 0x00 0 512
    qemu-io> read -v 0 512
    00000000:  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    ...

And similarly with discard instead of "write -z".

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-12-03 15:26:49 +01:00
Paolo Bonzini d0b4503ed2 raw-posix: implement write_zeroes with MAY_UNMAP for block devices
See the next commit for the description of the Linux kernel problem
that is worked around in raw_open_common.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-12-03 15:26:49 +01:00
Paolo Bonzini 260a82e524 raw-posix: implement write_zeroes with MAY_UNMAP for files
Writing zeroes to a file can be done by punching a hole if
MAY_UNMAP is set.

Note that in this case ENOTSUP is not ignored, but makes
the block layer fall back to the generic implementation.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-12-03 15:26:49 +01:00
Paolo Bonzini fa6252b056 block/iscsi: check WRITE SAME support differently depending on MAY_UNMAP
The current check is right for MAY_UNMAP=1.  For MAY_UNMAP=0, just
try and fall back to regular writes as soon as a WRITE SAME command
fails.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-12-03 15:26:49 +01:00
Peter Lieven 2af8a1a704 block/iscsi: updated copyright
added myself to reflect recent work on the iscsi block driver.

Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-12-03 15:26:49 +01:00
Peter Lieven 4b52498e62 block/iscsi: remove .bdrv_has_zero_init
since commit 3ac21627 the default value changed to 0.

Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-12-03 15:26:49 +01:00
Paolo Bonzini cffb1ec600 block drivers: expose requirement for write same alignment from formats
This will let misaligned but large requests use zero clusters.  This
is important because the cluster size is not guest visible.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-12-03 15:26:49 +01:00
Paolo Bonzini 95de6d7078 block drivers: add discard/write_zeroes properties to bdrv_get_info implementation
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-12-03 15:26:49 +01:00
Paolo Bonzini 97b00e2851 vpc, vhdx: add get_info
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-12-03 15:26:49 +01:00
Paolo Bonzini 7ce21016b6 block: handle ENOTSUP from discard in generic code
Similar to write_zeroes, let the generic code receive a ENOTSUP for
discard operations.  Since bdrv_discard has advisory semantics,
we can just swallow the error.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-12-03 15:26:49 +01:00
Fam Zheng af057fe740 vmdk: Fix creating big description file
The buffer for description file was 4096 which only covers a few
hundred of extents. This changes the buffer to dynamic allocated with
g_strdup_printf in order to support bigger cases.

Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-12-03 09:54:16 +01:00
Fam Zheng 509d39aa22 vmdk: Allow read only open of VMDK version 3
Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-11-29 17:41:14 +01:00
Kevin Wolf c9fbb99d41 block: Use BDRV_O_NO_BACKING where appropriate
If you open an image temporarily just because you want to check its size
or get it flushed, there's no real reason to open the whole backing file
chain.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
2013-11-29 17:41:09 +01:00
Fam Zheng 4cc70e9337 blkdebug: add "remove_break" command
This adds "remove_break" command which is the reverse of blkdebug
command "break": it removes all breakpoints with given tag and resumes
all the requests.

Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-11-29 13:40:37 +01:00
Liu Yuan b3af018f3b sheepdog: support user-defined redundancy option
Sheepdog support two kinds of redundancy, full replication and erasure coding.

# create a fully replicated vdi with x copies
 -o redundancy=x (1 <= x <= SD_MAX_COPIES)

# create a erasure coded vdi with x data strips and y parity strips
 -o redundancy=x:y (x must be one of {2,4,8,16} and 1 <= y < SD_EC_MAX_STRIP)

E.g, to convert a vdi into sheepdog vdi 'test' with 8:3 erasure coding scheme

$ qemu-img convert -o redundancy=8:3 linux-0.2.img sheepdog:test

Cc: Kevin Wolf <kwolf@redhat.com>
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Liu Yuan <namei.unix@gmail.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-11-29 13:40:37 +01:00
Liu Yuan c31d482f29 sheepdog: refactor do_sd_create()
We can actually use BDRVSheepdogState *s to pass most of the parameters.

Cc: Kevin Wolf <kwolf@redhat.com>
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Liu Yuan <namei.unix@gmail.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-11-29 13:40:37 +01:00
Charlie Shepherd 091b1108ca COW: Extend checking allocated bits to beyond one sector
cow_co_is_allocated() only checks one sector's worth of allocated bits
before returning. This is allowed but (slightly) inefficient, so extend
it to check all of the file's metadata sectors.

Signed-off-by: Charlie Shepherd <charlie@ctshepherd.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

[kwolf: silenced compiler warning (-Wmaybe-uninitialized for changed)]
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-11-29 13:40:36 +01:00
Charlie Shepherd 14b98fdaf3 COW: Speed up writes
Process a whole sector's worth of COW bits by reading a sector, setting
the bits after skipping any already set bits, then writing it out again.
Make sure we only flush once before writing metadata, and only if we
need to write metadata.

Signed-off-by: Charlie Shepherd <charlie@ctshepherd.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-11-29 13:40:36 +01:00
Fam Zheng 21b5683508 qapi: Change BlockDirtyInfo to list
We have multiple dirty bitmaps in BDS now, switch QAPI to allow query
it (BlockInfo.dirty_bitmaps), and also drop old BlockInfo.dirty.

Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-11-29 13:40:36 +01:00
Fam Zheng e4654d2d94 block: per caller dirty bitmap
Previously a BlockDriverState has only one dirty bitmap, so only one
caller (e.g. a block job) can keep track of writing. This changes the
dirty bitmap to a list and creates a BdrvDirtyBitmap for each caller, the
lifecycle is managed with these new functions:

    bdrv_create_dirty_bitmap
    bdrv_release_dirty_bitmap

Where BdrvDirtyBitmap is a linked list wrapper structure of HBitmap.

In place of bdrv_set_dirty_tracking, a BdrvDirtyBitmap pointer argument
is added to these functions, since each caller has its own dirty bitmap:

    bdrv_get_dirty
    bdrv_dirty_iter_init
    bdrv_get_dirty_count

bdrv_set_dirty and bdrv_reset_dirty prototypes are unchanged but will
internally walk the list of all dirty bitmaps and set them one by one.

Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-11-29 13:40:33 +01:00
Max Reitz f4a193e717 block/stream: Don't stream unbacked devices
If a block device is unbacked, a streaming blockjob should immediately
finish instead of beginning to try to stream, then noticing the backing
file does not contain even the first sector (since it does not exist)
and then finishing normally.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-11-28 11:39:31 +01:00
Liu Yuan 8582972227 sheepdog: implement .bdrv_get_allocated_file_size
With this patch, qemu-img info sheepdog:image will show disk size for sheepdog
images.

Cc: Kevin Wolf <kwolf@redhat.com>
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Cc: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>
Signed-off-by: Liu Yuan <namei.unix@gmail.com>
Reviewed-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-11-28 10:30:52 +01:00
Peter Lieven d4cd961507 iscsi: add bdrv_co_write_zeroes
Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-11-28 10:30:52 +01:00
Peter Lieven 01a6a238a3 iscsi: simplify iscsi_co_discard
now that bdrv_co_discard can handle limits we do not need
the request split logic here anymore.

Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-11-28 10:30:52 +01:00
Peter Lieven ba6c59191f iscsi: set limits in BlockDriverState
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-11-28 10:30:52 +01:00
Peter Lieven 04f19e4d2d block/raw: copy BlockLimits on raw_open
Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-11-28 10:30:51 +01:00
Peter Lieven 186d4f2b1d block/iscsi: add .bdrv_get_info
Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-11-28 10:30:51 +01:00
Peter Lieven d32f35cbc5 block: introduce BDRV_REQ_MAY_UNMAP request flag
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-11-28 10:30:51 +01:00
Peter Lieven aa7bfbfff7 block: add flags to bdrv_*_write_zeroes
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-11-28 10:30:51 +01:00
Peter Lieven 78a52ad5ac qcow2: fix possible corruption when reading multiple clusters
if multiple sectors spanning multiple clusters are read the
function count_contiguous_clusters should ensure that the
cluster type should not change between the clusters.

Especially the for-loop should break when we have one
or more normal clusters followed by a compressed cluster.

Unfortunately the wrong macro was used in the mask to
compare the flags.

This was discovered while debugging a data corruption
issue when converting a compressed qcow2 image to raw.
qemu-img reads 2MB chunks which span multiple clusters.

CC: qemu-stable@nongnu.org
Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-11-14 13:09:07 +01:00
Fam Zheng b04b6b6ec3 block: Print its file name if backing file opening failed
If backing file doesn't exist, the error message is confusing and
misleading:

    $ qemu /tmp/a.qcow2
    qemu: could not open disk image /tmp/a.qcow2: Could not open file: No
    such file or directory

But...

    $ ls /tmp/a.qcow2
    /tmp/a.qcow2

    $ qemu-img info /tmp/a.qcow2
    image: /tmp/a.qcow2
    file format: qcow2
    virtual size: 8.0G (8589934592 bytes)
    disk size: 196K
    cluster_size: 65536
    backing file: /tmp/b.qcow2

Because...

    $ ls /tmp/b.qcow2
    ls: cannot access /tmp/b.qcow2: No such file or directory

This is not intuitive. It's better to have the missing file's name in
the error message. With this patch:

    $ qemu-io -c 'read 0 512' /tmp/a.qcow2
    qemu-io: can't open device /tmp/a.qcow2: Could not open backing
    file: Could not open '/stor/vm/arch.raw': No such file or directory
    no file open, try 'help open'

Which is a little bit better.

Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2013-11-14 13:09:06 +01:00
Jeff Cody 3412f7b1bd 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>
2013-11-07 13:58:59 +01:00
Jeff Cody 61c02e5687 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>
2013-11-07 13:58:59 +01:00
Jeff Cody 1e74a971cb 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>
2013-11-07 13:58:59 +01:00
Jeff Cody c325ee1de8 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>
2013-11-07 13:58:59 +01:00
Jeff Cody 0b7da092b4 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>
2013-11-07 13:58:59 +01:00
Jeff Cody d92aa8833c 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>
2013-11-07 13:58:59 +01:00
Jeff Cody 8adc52336d 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>
2013-11-07 13:58:59 +01:00
Jeff Cody 1a848fd451 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>
2013-11-07 13:58:59 +01:00
Jeff Cody 0a43a1b5d7 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>
2013-11-07 13:58:58 +01:00
Jeff Cody c46415afc2 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>
2013-11-07 13:58:58 +01:00
Jeff Cody c3906c5e82 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>
2013-11-07 13:58:58 +01:00
Jeff Cody 0f48e8f097 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>
2013-11-07 13:58:58 +01:00
Jeff Cody 625565d27e 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>
2013-11-07 13:58:58 +01:00