Signed-off-by: NDon Koch <dkoch@verizon.com>
Signed-off-by: NMichael Tokarev <mjt@tls.msk.ru>

Signed-off-by: NDon Koch <dkoch@verizon.com>
Signed-off-by: NMichael Tokarev <mjt@tls.msk.ru>

Signed-off-by: NGonglei <arei.gonglei@huawei.com>
Signed-off-by: NMichael Tokarev <mjt@tls.msk.ru>

Commit fecd2646 added a number of fall-throughs, but neglected to
properly document them as intentional.  Commit d9224450 cleaned that up
for many, but not all cases.  Take care of the remaining ones.

Spotted by Coverity.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Signed-off-by: NMichael Tokarev <mjt@tls.msk.ru>

Signed-off-by: NLeon Yu <chianglungyu@gmail.com>
Message-id: 1422853731-5282-1-git-send-email-chianglungyu@gmail.com
Fixes: df887684 ("monitor: add query-vnc-servers command")
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

Block patches for 2.3

# gpg: Signature made Fri 06 Feb 2015 17:14:10 GMT using RSA key ID C88F2FD6
# gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>"

* remotes/kevin/tags/for-upstream: (47 commits)
  block/raw-posix.c: Fix raw_getlength() on Mac OS X block devices
  block: Eliminate silly QERR_ macros used for encryption keys
  block: New bdrv_add_key(), convert monitor to use it
  blockdev: Eliminate silly QERR_BLOCK_JOB_NOT_ACTIVE macro
  blockdev: Give find_block_job() an Error ** parameter
  qcow2: Rewrite qcow2_alloc_bytes()
  block: Give always priority to unused entries in the qcow2 L2 cache
  nbd: fix max_discard/max_transfer_length
  block: introduce BDRV_REQUEST_MAX_SECTORS
  nbd: Improve error messages
  iotests: Fix 104 for NBD
  iotests: Fix 100 for nbd
  iotests: Fix 083
  block: fix off-by-one error in qcow and qcow2
  qemu-iotests: add 116 invalid QED input file tests
  qed: check for header size overflow
  block/dmg: improve zeroes handling
  block/dmg: support bzip2 block entry types
  block/dmg: factor out block type check
  block/dmg: use SectorNumber from BLKX header
  ...
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

This patch replaces the dummy code in raw_getlength() for block devices
on OS X, which always returned LLONG_MAX, with a real implementation
that returns the actual block device size.
Signed-off-by: NJohn Arbuckle <programmingkidx@gmail.com>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Tested-by: NPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

* mreitz/block:
  block: Eliminate silly QERR_ macros used for encryption keys
  block: New bdrv_add_key(), convert monitor to use it
  blockdev: Eliminate silly QERR_BLOCK_JOB_NOT_ACTIVE macro
  blockdev: Give find_block_job() an Error ** parameter

The QERR_ macros are leftovers from the days of "rich" error objects.
They're used with error_set() and qerror_report(), and expand into the
first *two* arguments.  This trickiness has become pointless.  Clean
up QERR_DEVICE_ENCRYPTED and QERR_DEVICE_NOT_ENCRYPTED.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Message-id: 1422524221-8566-5-git-send-email-armbru@redhat.com
Reviewed-by: NMax Reitz <mreitz@redhat.com>
Signed-off-by: NMax Reitz <mreitz@redhat.com>

Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Message-id: 1422524221-8566-4-git-send-email-armbru@redhat.com
Reviewed-by: NMax Reitz <mreitz@redhat.com>
Signed-off-by: NMax Reitz <mreitz@redhat.com>

The QERR_ macros are leftovers from the days of "rich" error objects.
They're used with error_set() and qerror_report(), and expand into the
first *two* arguments.  This trickiness has become pointless.  Clean
this one up.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Message-id: 1422524221-8566-3-git-send-email-armbru@redhat.com
Reviewed-by: NMax Reitz <mreitz@redhat.com>
Signed-off-by: NMax Reitz <mreitz@redhat.com>

When find_block_job() fails, all its callers build the same Error
object.  Build it in find_block_job() instead.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Message-id: 1422524221-8566-2-git-send-email-armbru@redhat.com
Reviewed-by: NMax Reitz <mreitz@redhat.com>
Signed-off-by: NMax Reitz <mreitz@redhat.com>

qcow2_alloc_bytes() is a function with insufficient error handling and
an unnecessary goto. This patch rewrites it.
Signed-off-by: NMax Reitz <mreitz@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

The current algorithm to replace entries from the L2 cache gives
priority to newer hits by dividing the hit count of all existing
entries by two everytime there is a cache miss.

However, if there are several cache misses the hit count of the
existing entries can easily go down to 0. This will result in those
entries being replaced even when there are others that have never been
used.

This problem is more noticeable with larger disk images and cache
sizes, since the chances of having several misses before the cache is
full are higher.

If we make sure that the hit count can never go down to 0 again,
unused entries will always have priority.
Signed-off-by: NAlberto Garcia <berto@igalia.com>
Reviewed-by: NMax Reitz <mreitz@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

nbd_co_discard calls nbd_client_session_co_discard which uses uint32_t
as the length in bytes of the data to discard due to the following
definition:

struct nbd_request {
    uint32_t magic;
    uint32_t type;
    uint64_t handle;
    uint64_t from;
    uint32_t len; <-- the length of data to be discarded, in bytes
} QEMU_PACKED;

Thus we should limit bl_max_discard to UINT32_MAX >> BDRV_SECTOR_BITS to
avoid overflow.

NBD read/write code uses the same structure for transfers. Fix
max_transfer_length accordingly.
Signed-off-by: NDenis V. Lunev <den@openvz.org>
CC: Peter Lieven <pl@kamp.de>
CC: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

we check and adjust request sizes at several places with
sometimes inconsistent checks or default values:
 INT_MAX
 INT_MAX >> BDRV_SECTOR_BITS
 UINT_MAX >> BDRV_SECTOR_BITS
 SIZE_MAX >> BDRV_SECTOR_BITS

This patches introdocues a macro for the maximal allowed sectors
per request and uses it at several places.
Signed-off-by: NPeter Lieven <pl@kamp.de>
Reviewed-by: NDenis V. Lunev <den@openvz.org>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

This patch makes use of the Error object for nbd_receive_negotiate() so
that errors during negotiation look nicer.

Furthermore, this patch adds an additional error message if the received
magic was wrong, but would be correct for the other protocol version,
respectively: So if an export name was specified, but the NBD server
magic corresponds to an old handshake, this condition is explicitly
signaled to the user, and vice versa.

As these messages are now part of the "Could not open image" error
message, additional filtering has to be employed in iotest 083, which
this patch does as well.
Signed-off-by: NMax Reitz <mreitz@redhat.com>
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

_make_test_img sets up an NBD server, _cleanup_test_img shuts it down;
thus, _cleanup_test_img has to be called before _make_test_img is
invoked another time.

Furthermore, the pipe through _filter_test_img was unnecessary;
_make_test_img already takes care of that.

And finally, a filter is added to _filter_img_info to replace
"nbd://127.0.0.1:10810" by "TEST_DIR/t.IMGFMT", since the former is the
way to express the full image path (normally the latter) for NBD tests.
Signed-off-by: NMax Reitz <mreitz@redhat.com>
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

In case of NBD, _make_test_img starts a new NBD server. Therefore,
_cleanup_test_img (which shuts that server down) has to be invoked
before the next _make_test_img call in order to make 100 work for NBD.
Signed-off-by: NMax Reitz <mreitz@redhat.com>
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

As of 8f9e835f, probing should be
disabled in the qemu-iotests (at least when using qemu-io). This broke
083's reference output (which consisted mostly of "Could not read image
for determining its format").

This patch fixes it.

Note that one case which failed before is now successful: Disconnect
after data. This is due to qemu having read twice before (once for
probing, once for the qemu-io read command), but only once now (the
qemu-io read command). Therefore, reading is successful (which is
correct).
Signed-off-by: NMax Reitz <mreitz@redhat.com>
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

This fixes an off-by-one error introduced in 9a29e18f.  Both qcow and
qcow2 need to make sure to leave room for string terminator '\0' for
the backing file, so the max length of the non-terminated string is
either 1023 or PATH_MAX - 1.
Reported-by: NKevin Wolf <kwolf@redhat.com>
Signed-off-by: NJeff Cody <jcody@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

These tests exercise error code paths in the QED image format.  The
tests are very simple, they just prove that the error path exits
cleanly.
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
Message-id: 1421065893-18875-3-git-send-email-stefanha@redhat.com
Reviewed-by: NKevin Wolf <kwolf@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Header size is denoted in clusters.  The maximum cluster size is 64 MB
but there is no limit on header size.  Check for uint32_t overflow in
case the header size field has a whacky value.
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
Message-id: 1421065893-18875-2-git-send-email-stefanha@redhat.com
Reviewed-by: NKevin Wolf <kwolf@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Disk images may contain large all-zeroes gaps (1.66k sectors or 812 MiB
is seen in the real world). These blocks (type 2) do not need to be
extracted into a temporary buffer, there is no need to allocate memory
for these blocks nor to check its length.

(For the test image, the maximum uncompressed size is 1054371 bytes,
probably for a bzip2-compressed block.)
Signed-off-by: NPeter Wu <peter@lekensteyn.nl>
Reviewed-by: NJohn Snow <jsnow@redhat.com>
Message-id: 1420566495-13284-13-git-send-email-peter@lekensteyn.nl
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

This patch adds support for bzip2-compressed block entries as introduced
with OS X 10.4 (source: https://en.wikipedia.org/wiki/Apple_Disk_Image).

It was tested against a 5.2G "OS X Yosemite" installation image which
stores the BLXX block in the XML property list (instead of resource
forks) and has over 5k chunks.

New configure entries are added (--enable-bzip2 / --disable-bzip2) to
control inclusion of bzip2 functionality (which requires linking against
libbz2). The help message suggests that this option is needed for DMG
files, but the tests are generic enough that other parts of QEMU can use
bzip2 if needed.

The identifiers are based on http://newosxbook.com/DMG.html.

The decompression routines are based on the zlib case, but as there is
no way to reset the decompression state (unlike zlib), memory is
allocated and deallocated for every decompression. This should not be
problematic as the decompression takes most of the time and as blocks
are typically about/over 1 MiB in size, only one allocation is done
every 2000 sectors.
Signed-off-by: NPeter Wu <peter@lekensteyn.nl>
Reviewed-by: NJohn Snow <jsnow@redhat.com>
Acked-by: NPaolo Bonzini <pbonzini@redhat.com>
Message-id: 1420566495-13284-12-git-send-email-peter@lekensteyn.nl
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

In preparation for adding bzip2 support, split the type check into a
separate function. Make all offsets relative to the begin of a chunk
such that it is easier to recognize the position without having to
add up all offsets. Some comments are added to describe the fields.

There is no functional change.
Signed-off-by: NPeter Wu <peter@lekensteyn.nl>
Reviewed-by: NJohn Snow <jsnow@redhat.com>
Message-id: 1420566495-13284-11-git-send-email-peter@lekensteyn.nl
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Previously the sector table parsing relied on the previous offset of
the DMG file. Now it uses the sector number from the BLKX header
(see http://newosxbook.com/DMG.html).

The implementation of dmg2img (from vu1tur) does not base the output
sector on the location of the terminator (0xffffffff) either so it
should be safe to drop this dependency on the previous state.

(It makes somehow makes sense, a terminator should halt further
processing of a block and is perhaps used to preallocate some space.)
Signed-off-by: NPeter Wu <peter@lekensteyn.nl>
Reviewed-by: NJohn Snow <jsnow@redhat.com>
Message-id: 1420566495-13284-10-git-send-email-peter@lekensteyn.nl
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

This patch addresses two issues:

 - The data fork offset was not taken into account, resulting in failure
   to read an InstallESD.dmg file (5164763151 bytes) which had a
   non-zero DataForkOffset field.
 - The offset of the previous block ("partition") was unconditionally
   added to the current block because older files would start the input
   offset of a new block at zero. Newer files (including vlc-2.1.5.dmg,
   tuxpaint-0.9.15-macosx.dmg and OS X Yosemite [MAS].dmg) failed in
   reads because these files have chunk offsets, relative to the begin
   of a data fork.

Now the data offset of the mish is taken into account. While we could
check that the data_offset is within the data fork, let's not do that
here as it would only result in parse failures on invalid files (rather
than gracefully handling such bad files). dmg_read will error out if
the offset is incorrect.
Signed-off-by: NPeter Wu <peter@lekensteyn.nl>
Reviewed-by: NJohn Snow <jsnow@redhat.com>
Message-id: 1420566495-13284-9-git-send-email-peter@lekensteyn.nl
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Right now the virtual size is always reported as zero which makes it
impossible to convert between formats.

After this patch, the number of sectors will be read from the trailer
("koly" block).

To verify the behavior, the output of `dmg2img foo.dmg foo.img` was
compared against `qemu-img convert -f dmg -O raw foo.dmg foo.raw`. The
tests showed that the file contents are exactly the same, except that
QEMU creates a slightly larger file (it matches the total sectors
count).
Signed-off-by: NPeter Wu <peter@lekensteyn.nl>
Reviewed-by: NJohn Snow <jsnow@redhat.com>
Message-id: 1420566495-13284-8-git-send-email-peter@lekensteyn.nl
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

The format is simple enough to avoid using a full-blown XML parser. It
assumes that all BLKX items begin with the "mish" magic word, therefore
it is not a problem if other values get matched which are not a BLKX
block.

The offsets are based on the description at
http://newosxbook.com/DMG.html

For compatibility with glib 2.12, use g_base64_decode (which
additionally requires an extra buffer allocation) instead of
g_base64_decode_inplace (which is only available since glib 2.20).
Signed-off-by: NPeter Wu <peter@lekensteyn.nl>
Reviewed-by: NJohn Snow <jsnow@redhat.com>
Message-id: 1420566495-13284-7-git-send-email-peter@lekensteyn.nl
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Previously the chunk size was not checked, allowing for a large memory
allocation. This patch checks whether the chunks size is within the
resource fork length, and whether the resource fork is below the
trailer of the dmg file.
Signed-off-by: NPeter Wu <peter@lekensteyn.nl>
Reviewed-by: NJohn Snow <jsnow@redhat.com>
Message-id: 1420566495-13284-6-git-send-email-peter@lekensteyn.nl
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

As the decoded plist XML is not a pointer in the file,
dmg_read_mish_block must be able to process a buffer instead of a file
pointer. Since the full buffer must be processed, let's change the
return value again to just a success flag.
Signed-off-by: NPeter Wu <peter@lekensteyn.nl>
Reviewed-by: NJohn Snow <jsnow@redhat.com>
Message-id: 1420566495-13284-5-git-send-email-peter@lekensteyn.nl
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Besides the offset, also read the resource length. This length is now
used in the extracted function to verify the end of the resource fork
against "count" from the resource fork.

Instead of relying on the value of offset to conclude whether the
resource fork is available or not (info_begin==0), check the
rsrc_fork_length instead. This would allow a dmg file to begin with a
resource fork. This seemingly unnecessary restriction was found while
trying to craft a DMG file by hand.

Other changes:

 - Do not require resource data offset to be 0x100 (but check that it
   is within bounds though).
 - Further improve boundary checking (resource data must be within
   the resource fork).
 - Use correct value for resource data length (spotted by John Snow)
 - Consider the resource data offset when determining info_end.
   This fixes an EINVAL on the tuxpaint dmg example.

The resource fork format is documented at
https://developer.apple.com/legacy/library/documentation/mac/pdf/MoreMacintoshToolbox.pdf#page=151Signed-off-by: NPeter Wu <peter@lekensteyn.nl>
Reviewed-by: NJohn Snow <jsnow@redhat.com>
Message-id: 1420566495-13284-4-git-send-email-peter@lekensteyn.nl
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Extract the mish block decoder such that this can be used for other
formats in the future. A new DmgHeaderState struct is introduced to
share state while decoding.

The code is kept unchanged as much as possible, a "fail" label is added
for example where a simple return would probably do. In dmg_open, the
variable "tmp" is renamed to "rsrc_data_offset" for clarity and comments
have been added explaining various data.

Note that this patch has one subtle difference with the previous
version which should not affect functionality. In the previous code,
the end of a resource was inferred from the mish block (the offsets
would be increased by the fields). In this patch, the resource length
is used instead to avoid the need to rely on the previous offsets.
Signed-off-by: NPeter Wu <peter@lekensteyn.nl>
Reviewed-by: NJohn Snow <jsnow@redhat.com>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Message-id: 1420566495-13284-3-git-send-email-peter@lekensteyn.nl
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

DMG files have a variable length with a UDIF trailer at the end of a
file. This UDIF trailer is essential as it describes the contents of
the image. At the moment however, the start of this trailer is almost
always incorrect as bdrv_getlength() returns a multiple of the block
size (rounded up). This results in a failure to recognize DMG files,
resulting in Invalid argument (EINVAL) errors.

As there is no API to retrieve the real file size, look for the magic
header in the last two sectors to find the start of this 512-byte UDIF
trailer (the "koly" block).

The resource fork offset ("info_begin") has its offset adjusted as the
initial value of offset does not mean "end of file" anymore, but "begin
of UDIF trailer".

[Replaced error_set(errp, ERROR_CLASS_GENERIC_ERROR, ...) with
error_setg(errp, ...) as discussed with Peter.
--Stefan]
Signed-off-by: NPeter Wu <peter@lekensteyn.nl>
Reviewed-by: NJohn Snow <jsnow@redhat.com>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Message-id: 1420566495-13284-2-git-send-email-peter@lekensteyn.nl
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Managing applications, like oVirt (http://www.ovirt.org), make extensive
use of thin-provisioned disk images.
To let the guest run smoothly and be not unnecessarily paused, oVirt sets
a disk usage threshold (so called 'high water mark') based on the occupation
of the device,  and automatically extends the image once the threshold
is reached or exceeded.

In order to detect the crossing of the threshold, oVirt has no choice but
aggressively polling the QEMU monitor using the query-blockstats command.
This lead to unnecessary system load, and is made even worse under scale:
deployments with hundreds of VMs are no longer rare.

To fix this, this patch adds:
* A new monitor command `block-set-write-threshold', to set a mark for
  a given block device.
* A new event `BLOCK_WRITE_THRESHOLD', to report if a block device
  usage exceeds the threshold.
* A new `write_threshold' field into the `BlockDeviceInfo' structure,
  to report the configured threshold.

This will allow the managing application to use smarter and more
efficient monitoring, greatly reducing the need of polling.

[Updated qemu-iotests 067 output to add the new 'write_threshold'
property. --Stefan]
[Changed g_assert_false() to !g_assert() to fix the build on older glib
versions. --Kevin]
Signed-off-by: NFrancesco Romani <fromani@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Message-id: 1421068273-692-1-git-send-email-fromani@redhat.com
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

This patch is necessary to suppress the "probed raw" warning when
running raw over nbd tests.
Signed-off-by: NMax Reitz <mreitz@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

There is a bug in the recently added sys.platform test, and we no longer
run python tests, because "linux2" is the value to compare here. So do a
prefix match. According to python doc [1], the way to use sys.platform
is "unless you want to test for a specific system version, it is
therefore recommended to use the following idiom":

if sys.platform.startswith('freebsd'):
    # FreeBSD-specific code here...
elif sys.platform.startswith('linux'):
    # Linux-specific code here...

[1]: https://docs.python.org/2.7/library/sys.html#sys.platformSigned-off-by: NFam Zheng <famz@redhat.com>
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

this adds a knob to disable request merging for debugging or benchmarks if dedired.
Signed-off-by: NPeter Lieven <pl@kamp.de>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

this patch finally introduces multiread support to virtio-blk. While
multiwrite support was there for a long time, read support was missing.

The complete merge logic is moved into virtio-blk.c which has
been the only user of request merging ever since. This is required
to be able to merge chunks of requests and immediately invoke callbacks
for those requests. Secondly, this is required to switch to
direct invocation of coroutines which is planned at a later stage.

The following benchmarks show the performance of running fio with
4 worker threads on a local ram disk. The numbers show the average
of 10 test runs after 1 run as warmup phase.

              |        4k        |       64k        |        4k
MB/s          | rd seq | rd rand | rd seq | rd rand | wr seq | wr rand
--------------+--------+---------+--------+---------+--------+--------
master        | 1221   | 1187    | 4178   | 4114    | 1745   | 1213
multiread     | 1829   | 1189    | 4639   | 4110    | 1894   | 1216
Signed-off-by: NPeter Lieven <pl@kamp.de>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>