Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

Miscellaneous patches for 2019-04-02

# gpg: Signature made Tue 02 Apr 2019 12:54:27 BST
# gpg:                using RSA key 3870B400EB918653
# gpg: Good signature from "Markus Armbruster <armbru@redhat.com>" [full]
# gpg:                 aka "Markus Armbruster <armbru@pond.sub.org>" [full]
# Primary key fingerprint: 354B C8B3 D7EB 2A6B 6867  4E5F 3870 B400 EB91 8653

* remotes/armbru/tags/pull-misc-2019-04-02:
  accel: Unbreak accelerator fallback
  vl: Document dependencies hiding in global and compat props
  migration: Support adding migration blockers earlier
  Revert "migration: move only_migratable to MigrationState"
  Revert "vl: Fix to create migration object before block backends again"
  qapi/migration.json: Rename COLOStatus last_mode to last-mode
  qapi/migration.json: Fix ColoStatus member last_mode's version
  vl: Fix error location of positional arguments

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

filemon: various fixes / improvements to file monitor for USB MTP

Ensure watch IDs unique within a monitor and avoid integer wraparound
issues when many watches are set & unset over time.

# gpg: Signature made Tue 02 Apr 2019 13:53:40 BST
# gpg:                using RSA key BE86EBB415104FDF
# gpg: Good signature from "Daniel P. Berrange <dan@berrange.com>" [full]
# gpg:                 aka "Daniel P. Berrange <berrange@redhat.com>" [full]
# Primary key fingerprint: DAF3 A6FD B26B 6291 2D0E  8E3F BE86 EBB4 1510 4FDF

* remotes/berrange/tags/filemon-next-pull-request:
  filemon: fix watch IDs to avoid potential wraparound issues
  filemon: ensure watch IDs are unique to QFileMonitor scope
  tests: refactor file monitor test to make it more understandable

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

Block layer patches:

- file-posix: Ignore unlock failure instead of crashing
- gluster: Limit the transfer size to 512 MiB
- stream: Fix backing chain freezing
- qemu-img: Enable BDRV_REQ_MAY_UNMAP for zero writes in convert
- iotests fixes

# gpg: Signature made Tue 02 Apr 2019 13:47:43 BST
# gpg:                using RSA key 7F09B272C88F2FD6
# gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>" [full]
# Primary key fingerprint: DC3D EB15 9A9A F95D 3D74  56FE 7F09 B272 C88F 2FD6

* remotes/kevin/tags/for-upstream:
  tests/qemu-iotests/235: Allow fallback to tcg
  block: test block-stream with a base node that is used by block-commit
  block: freeze the backing chain earlier in stream_start()
  block: continue until base is found in bdrv_freeze_backing_chain() et al
  block/file-posix: do not fail on unlock bytes
  tests/qemu-iotests: Remove redundant COPYING file
  block/gluster: limit the transfer size to 512 MiB
  qemu-img: Enable BDRV_REQ_MAY_UNMAP in convert
  iotests: Fix test 200 on s390x without virtio-pci

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

Watch IDs are allocated from incrementing a int counter against
the QFileMonitor object. In very long life QEMU processes with
a huge amount of USB MTP activity creating & deleting directories
it is just about conceivable that the int counter can wrap
around. This would result in incorrect behaviour of the file
monitor watch APIs due to clashing watch IDs.

Instead of trying to detect this situation, this patch changes
the way watch IDs are allocated. It is turned into an int64_t
variable where the high 32 bits are set from the underlying
inotify "int" ID. This gives an ID that is guaranteed unique
for the directory as a whole, and we can rely on the kernel
to enforce this. QFileMonitor then sets the low 32 bits from
a per-directory counter.

The USB MTP device only sets watches on the directory as a
whole, not files within, so there is no risk of guest
triggered wrap around on the low 32 bits.

Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>

The watch IDs are mistakenly only unique within the scope of the
directory being monitored. This is not useful for clients which are
monitoring multiple directories. They require watch IDs to be unique
globally within the QFileMonitor scope.

Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Tested-by: Bandan Das <bsd@redhat.com>
Reviewed-by: Bandan Das <bsd@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>

The current file monitor unit tests are too clever for their own good
making it hard to understand the desired output.

Instead of trying to infer the expected events, explicitly list the
events we expect in the operation sequence.

Instead of dynamically building a matrix of tests, just have one giant
operation sequence that validates all scenarios in a single test.

Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>

When the user specifies a list of accelerators, we pick the first one
that initializes successfully.  Recent commit 1a3ec8c1 broke that.
Reproducer:

    $ qemu-system-x86_64 --machine accel=xen:tcg
    xencall: error: Could not obtain handle on privileged command interface: No such file or directory
    xen be core: xen be core: can't open xen interface
    can't open xen interface
    qemu-system-x86_64: failed to initialize Xen: Operation not permitted
    qemu-system-x86_64: /home/armbru/work/qemu/qom/object.c:436: object_set_accelerator_compat_props: Assertion `!object_compat_props[0]' failed.

Root cause: we register accelerator compat properties even when the
accelerator fails.  The failed assertion is
object_set_accelerator_compat_props() telling us off.  Fix by calling
it only for the accelerator that succeeded.

Fixes: 1a3ec8c1
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20190401090827.20793-6-armbru@redhat.com>

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20190401090827.20793-5-armbru@redhat.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>

migrate_add_blocker() asserts we have a current_migration object, in
migrate_get_current().  We do only after migration_object_init().

This contributes to the following dependency cycle:

* configure_blockdev() must run before machine_set_property()
  so machine properties can refer to block backends

* machine_set_property() before configure_accelerator()
  so machine properties like kvm-irqchip get applied

* configure_accelerator() before migration_object_init()
  so that Xen's accelerator compat properties get applied.

* migration_object_init() before configure_blockdev()
  so configure_blockdev() can add migration blockers

The cycle was closed when recent commit cda4aa9a "Create block
backends before setting machine properties" added the first
dependency, and satisfied it by violating the last one.  Broke block
backends that add migration blockers, as demonstrated by qemu-iotests
055.

To fix it, break the last dependency: make migrate_add_blocker()
usable before migration_object_init().

The previous commit already removed the use of migrate_get_current()
from migrate_add_blocker() itself.  Didn't quite do the trick, as
there's another one hiding in migration_is_idle().

The use there isn't actually necessary: when no migration object has
been created yet, migration is surely idle.  Make migration_is_idle()
return true then.

Fixes: cda4aa9a
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20190401090827.20793-4-armbru@redhat.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>

This reverts commit 3df663e5.
This reverts commit b605c47b.

Command line option --only-migratable is for disallowing any
configuration that can block migration.

Initially, --only-migratable set global variable @only_migratable.

Commit 3df663e5 "migration: move only_migratable to MigrationState"
replaced it by MigrationState member @only_migratable.  That was a
mistake.

First, it doesn't make sense on the design level.  MigrationState
captures the state of an individual migration, but --only-migratable
isn't a property of an individual migration, it's a restriction on
QEMU configuration.  With fault tolerance, we could have several
migrations at once.  --only-migratable would certainly protect all of
them.  Storing it in MigrationState feels inappropriate.

Second, it contributes to a dependency cycle that manifests itself as
a bug now.

Putting @only_migratable into MigrationState means its available only
after migration_object_init().

We can't set it before migration_object_init(), so we delay setting it
with a global property (this is fixup commit b605c47b "migration:
fix handling for --only-migratable").

We can't get it before migration_object_init(), so anything that uses
it can only run afterwards.

Since migrate_add_blocker() needs to obey --only-migratable, any code
adding migration blockers can run only afterwards.  This contributes
to the following dependency cycle:

* configure_blockdev() must run before machine_set_property()
  so machine properties can refer to block backends

* machine_set_property() before configure_accelerator()
  so machine properties like kvm-irqchip get applied

* configure_accelerator() before migration_object_init()
  so that Xen's accelerator compat properties get applied.

* migration_object_init() before configure_blockdev()
  so configure_blockdev() can add migration blockers

The cycle was closed when recent commit cda4aa9a "Create block
backends before setting machine properties" added the first
dependency, and satisfied it by violating the last one.  Broke block
backends that add migration blockers.

Moving @only_migratable into MigrationState was a mistake.  Revert it.

This doesn't quite break the "migration_object_init() before
configure_blockdev() dependency, since migrate_add_blocker() still has
another dependency on migration_object_init().  To be addressed the
next commit.

Note that the reverted commit made -only-migratable sugar for -global
migration.only-migratable=on below the hood.  Documentation has only
ever mentioned -only-migratable.  This commit removes the arcane &
undocumented alternative to -only-migratable again.  Nobody should be
using it.

Conflicts:
	include/migration/misc.h
	migration/migration.c
	migration/migration.h
	vl.c

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20190401090827.20793-3-armbru@redhat.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>

This reverts commit e60483f2.

Recent commit cda4aa9a moved block backend creation before machine
property evaluation.  This broke block backends registering migration
blockers.  Commit e60483f2 fixed it by moving migration object
creation before block backend creation.  This broke migration with
Xen.  Turns out we need to configure the accelerator before we create
the migration object so that Xen's accelerator compat properties get
applied.  Revert the flawed commit.  This fixes the Xen regression,
but brings back the block backend regression.  The next commits will
fix it again.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20190401090827.20793-2-armbru@redhat.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>

Signed-off-by: Zhang Chen <chen.zhang@intel.com>
Message-Id: <20190402085521.17973-1-chen.zhang@intel.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
[Commit message rephrased]
Signed-off-by: Markus Armbruster <armbru@redhat.com>

Signed-off-by: Zhang Chen <chen.zhang@intel.com>
Message-Id: <20190326174510.13303-1-chen.zhang@intel.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
[Commit message tweaked as per Eric's review]
Signed-off-by: Markus Armbruster <armbru@redhat.com>

We blame badness in positional arguments on the last option argument:

    $ qemu-system-x86_64 -vnc :1 bad.img
    qemu-system-x86_64: -vnc :1: Could not open 'foo': No such file or directory

I believe we've done this ever since we reported locations.  Fix it to

    qemu-system-x86_64: bad.img: Could not open 'bad.img': No such file or directory

Reported-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20190318183312.4684-1-armbru@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>

iotest 235 currently only works with KVM - this is bad for systems where
it is not available, e.g. CI pipelines. The test also works when using
"tcg" as accelerator, so we can simply add that to the list of accelerators,
too.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

The base node of a block-stream operation indicates the first image
from the backing chain starting from which no data is copied to the
top node.

The block-stream job allows others to use that base image, so a second
block-stream job could be writing to it at the same time. An important
restriction is that the base image must not disappear while the stream
job is ongoing. stream_start() freezes the backing chain from top to
base with that purpose but it does it too late in the code so there is
a race condition there.

This bug was fixed in the previous commit, and this patch contains an
iotest for this scenario.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

Commit 65854933 added code to freeze
the backing chain from 'top' to 'base' for the duration of the
block-stream job.

The problem is that the freezing happens too late in stream_start():
during the bdrv_reopen_set_read_only() call earlier in that function
another job can jump in and remove the base image. If that happens we
have an invalid chain and QEMU crashes.

This patch puts the bdrv_freeze_backing_chain() call at the beginning
of the function.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

All three functions that handle the BdrvChild.frozen attribute walk
the backing chain from 'bs' to 'base' and stop either when 'base' is
found or at the end of the chain if 'base' is NULL.

However if 'base' is not found then the functions return without
errors as if it was NULL.

This is wrong: if the caller passed an incorrect parameter that means
that there is a bug in the code.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

bdrv_replace_child() calls bdrv_check_perm() with error_abort on
loosening permissions. However file-locking operations may fail even
in this case, for example on NFS. And this leads to Qemu crash.

Let's avoid such errors. Note, that we ignore such things anyway on
permission update commit and abort.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

The file tests/qemu-iotests/COPYING is the same text as in the
COPYING file in the main directory. So as far as I can see, we don't
need the duplicate here.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

Several versions of GlusterFS (3.12? -> 6.0.1) fail when the
transfer size is greater or equal to 1024 MiB, so we are
limiting the transfer size to 512 MiB to avoid this rare issue.

Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=1691320


Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Niels de Vos <ndevos@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

With Kevin's "block: Fix slow pre-zeroing in qemu-img convert"[1]
(commit c9fdcf20, 'qemu-img: Use BDRV_REQ_NO_FALLBACK for
pre-zeroing') we skip the pre zero step called like this:

    blk_make_zero(s->target, BDRV_REQ_MAY_UNMAP | BDRV_REQ_NO_FALLBACK)

And we write zeroes later using:

    blk_co_pwrite_zeroes(s->target,
                         sector_num << BDRV_SECTOR_BITS,
                         n << BDRV_SECTOR_BITS, 0);

Since we use flags=0, this is translated to NBD_CMD_WRITE_ZEROES with
NBD_CMD_FLAG_NO_HOLE flag, which cause the NBD server to allocated space
instead of punching a hole.

Here is an example failure:

$ dd if=/dev/urandom of=src.img bs=1M count=5
$ truncate -s 50m src.img
$ truncate -s 50m dst.img
$ nbdkit -f -v -e '' -U nbd.sock file file=dst.img

$ ./qemu-img convert -n src.img nbd:unix:nbd.sock

We can see in nbdkit log that it received the NBD_CMD_FLAG_NO_HOLE
(may_trim=0):

nbdkit: file[1]: debug: newstyle negotiation: flags: export 0x4d
nbdkit: file[1]: debug: pwrite count=2097152 offset=0
nbdkit: file[1]: debug: pwrite count=2097152 offset=2097152
nbdkit: file[1]: debug: pwrite count=1048576 offset=4194304
nbdkit: file[1]: debug: zero count=33554432 offset=5242880 may_trim=0
nbdkit: file[1]: debug: zero count=13631488 offset=38797312 may_trim=0
nbdkit: file[1]: debug: flush

And the image became fully allocated:

$ qemu-img info dst.img
virtual size: 50M (52428800 bytes)
disk size: 50M

With this change we see that nbdkit did not receive the
NBD_CMD_FLAG_NO_HOLE (may_trim=1):

nbdkit: file[1]: debug: newstyle negotiation: flags: export 0x4d
nbdkit: file[1]: debug: pwrite count=2097152 offset=0
nbdkit: file[1]: debug: pwrite count=2097152 offset=2097152
nbdkit: file[1]: debug: pwrite count=1048576 offset=4194304
nbdkit: file[1]: debug: zero count=33554432 offset=5242880 may_trim=1
nbdkit: file[1]: debug: zero count=13631488 offset=38797312 may_trim=1
nbdkit: file[1]: debug: flush

And the file is sparse as expected:

$ qemu-img info dst.img
virtual size: 50M (52428800 bytes)
disk size: 5.0M

[1] http://lists.nongnu.org/archive/html/qemu-block/2019-03/msg00761.html



Signed-off-by: Nir Soffer <nsoffer@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

virtio-pci is optional on s390x, e.g. in downstream RHEL builds, it
is disabled. On s390x, virtio-ccw should be used instead. Other tests
like 051 or 240 already use virtio-scsi-ccw instead of virtio-scsi-pci
on s390x, so let's do the same here and always use virtio-scsi-ccw on
s390x.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

fixes for 4.0 (audio, usb),

# gpg: Signature made Tue 02 Apr 2019 07:46:22 BST
# gpg:                using RSA key 4CB6D8EED3E87138
# gpg: Good signature from "Gerd Hoffmann (work) <kraxel@redhat.com>" [full]
# gpg:                 aka "Gerd Hoffmann <gerd@kraxel.org>" [full]
# gpg:                 aka "Gerd Hoffmann (private) <kraxel@gmail.com>" [full]
# Primary key fingerprint: A032 8CFF B93A 17A7 9901  FE7D 4CB6 D8EE D3E8 7138

* remotes/kraxel/tags/fixes-20190402-pull-request:
  audio: fix audio timer rate conversion bug
  usb-mtp: remove usb_mtp_object_free_one
  usb-mtp: fix return status of delete
  hw/usb/bus.c: Handle "no speed matched" case in usb_mask_to_str()
  Revert "audio: fix pc speaker init"

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

Currently the default audio timer frequency is 10000Hz instead of
a period of 10000us. Also the audiodev timer-period property gets
converted like a frequency. Only handling of the legacy
QEMU_AUDIO_TIMER_PERIOD environment variable is correct because
it's actually a frequency.

With this patch the property timer-period is really a timer period
and QEMU_AUDIO_TIMER_PERIOD remains a frequency.

Fixes: 71830221 "-audiodev command line option basic implementation."
Signed-off-by: Volker Rümelin <vr_qemu@t-online.de>
Reviewed-by: Zoltán Kővágó <DirtY.iCE.hu@gmail.com>
Message-id: 90b95e4f-39ef-2b01-da6a-857ebaee1ec5@t-online.de
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

This function is used in the delete path only and can
be replaced by a call to usb_mtp_object_free.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Bandan Das <bsd@redhat.com>
Message-Id: <20190401211712.19012-3-bsd@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

Spotted by Coverity: CID 1399414

mtp delete allows the return status of delete succeeded,
partial_delete or readonly - when none of the objects could be
deleted. Give more meaningful names to return values of the
delete function.

Some initiators recurse over the objects themselves. In that case,
only READ_ONLY can be returned.

Signed-off-by: Bandan Das <bsd@redhat.com>
Message-Id: <20190401211712.19012-2-bsd@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

nbd patches for 2019-04-01

- Better behavior of qemu-img map on NBD images
- Fixes for NBD protocol alignment corner cases:
 - the server has fewer places where it sends reads or block status
   not aligned to its advertised block size
 - the client has more cases where it can work around server
   non-compliance present in qemu 3.1
 - the client now avoids non-compliant requests when interoperating
   with nbdkit or other servers not advertising block size

# gpg: Signature made Mon 01 Apr 2019 15:06:54 BST
# gpg:                using RSA key A7A16B4A2527436A
# gpg: Good signature from "Eric Blake <eblake@redhat.com>" [full]
# gpg:                 aka "Eric Blake (Free Software Programmer) <ebb9@byu.net>" [full]
# gpg:                 aka "[jpeg image of size 6874]" [full]
# Primary key fingerprint: 71C2 CC22 B1C4 6029 27D2  F3AA A7A1 6B4A 2527 436A

* remotes/ericb/tags/pull-nbd-2019-04-01:
  nbd/client: Trace server noncompliance on structured reads
  nbd/server: Advertise actual minimum block size
  block: Add bdrv_get_request_alignment()
  nbd/client: Support qemu-img convert from unaligned size
  nbd/client: Reject inaccessible tail of inconsistent server
  nbd/client: Report offsets in bdrv_block_status
  nbd/client: Lower min_block for block-status, unaligned size
  iotests: Add 241 to test NBD on unaligned images
  nbd-client: Work around server BLOCK_STATUS misalignment at EOF
  qemu-img: Gracefully shutdown when map can't finish
  nbd: Permit simple error to NBD_CMD_BLOCK_STATUS
  nbd: Don't lose server's error to NBD_CMD_BLOCK_STATUS
  nbd: Tolerate some server non-compliance in NBD_CMD_BLOCK_STATUS
  qemu-img: Report bdrv_block_status failures

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

Just as we recently added a trace for a server sending block status
that doesn't match the server's advertised minimum block alignment,
let's do the same for read chunks.  But since qemu 3.1 is such a
server (because it advertised 512-byte alignment, but when serving a
file that ends in data but is not sector-aligned, NBD_CMD_READ would
detect a mid-sector change between data and hole at EOF and the
resulting read chunks are unaligned), we don't want to change our
behavior of otherwise tolerating unaligned reads.

Note that even though we fixed the server for 4.0 to advertise an
actual block alignment (which gets rid of the unaligned reads at EOF
for posix files), we can still trigger it via other means:

$ qemu-nbd --image-opts driver=blkdebug,align=512,image.driver=file,image.filename=/path/to/non-aligned-file

Arguably, that is a bug in the blkdebug block status function, for
leaking a block status that is not aligned. It may also be possible to
observe issues with a backing layer with smaller alignment than the
active layer, although so far I have been unable to write a reliable
iotest for that scenario.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20190330165349.32256-1-eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

Both NBD_CMD_BLOCK_STATUS and structured NBD_CMD_READ will split their
reply according to bdrv_block_status() boundaries. If the block device
has a request_alignment smaller than 512, but we advertise a block
alignment of 512 to the client, then this can result in the server
reply violating client expectations by reporting a smaller region of
the export than what the client is permitted to address (although this
is less of an issue for qemu 4.0 clients, given recent client patches
to overlook our non-compliance at EOF).  Since it's always better to
be strict in what we send, it is worth advertising the actual minimum
block limit rather than blindly rounding it up to 512.

Note that this patch is not foolproof - it is still possible to
provoke non-compliant server behavior using:

$ qemu-nbd --image-opts driver=blkdebug,align=512,image.driver=file,image.filename=/path/to/non-aligned-file

That is arguably a bug in the blkdebug driver (it should never pass
back block status smaller than its alignment, even if it has to make
multiple bdrv_get_status calls and determine the
least-common-denominator status among the group to return). It may
also be possible to observe issues with a backing layer with smaller
alignment than the active layer, although so far I have been unable to
write a reliable iotest for that scenario (but again, an issue like
that could be argued to be a bug in the block layer, or something
where we need a flag to bdrv_block_status() to state whether the
result must be aligned to the current layer's limits or can be
subdivided for accuracy when chasing backing files).

Anyways, as blkdebug is not normally used, and as this patch makes our
server more interoperable with qemu 3.1 clients, it is worth applying
now, even while we still work on a larger patch series for the 4.1
timeframe to have byte-accurate file lengths.

Note that the iotests output changes - for 223 and 233, we can see the
server's better granularity advertisement; and for 241, the three test
cases have the following effects:
- natural alignment: the server's smaller alignment is now advertised,
and the hole reported at EOF is now the right result; we've gotten rid
of the server's non-compliance
- forced server alignment: the server still advertises 512 bytes, but
still sends a mid-sector hole. This is still a server compliance bug,
which needs to be fixed in the block layer in a later patch; output
does not change because the client is already being tolerant of the
non-compliance
- forced client alignment: the server's smaller alignment means that
the client now sees the server's status change mid-sector without any
protocol violations, but the fact that the map shows an unaligned
mid-sector hole is evidence of the block layer problems with aligned
block status, to be fixed in a later patch

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20190329042750.14704-7-eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
[eblake: rebase to enhanced iotest 241 coverage]

The next patch needs access to a device's minimum permitted
alignment, since NBD wants to advertise this to clients. Add
an accessor function, borrowing from blk_get_max_transfer()
for accessing a backend's block limits.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20190329042750.14704-6-eblake@redhat.com>

If an NBD server advertises a size that is not a multiple of a sector,
the block layer rounds up that size, even though we set info.size to
the exact byte value sent by the server. The block layer then proceeds
to let us read or query block status on the hole that it added past
EOF, which the NBD server is unlikely to be happy with. Fortunately,
qemu as a server never advertizes an unaligned size, so we generally
don't run into this problem; but the nbdkit server makes it easy to
test:

$ printf %1000d 1 > f1
$ ~/nbdkit/nbdkit -fv file f1 & pid=$!
$ qemu-img convert -f raw nbd://localhost:10809

 f2
$ kill $pid
$ qemu-img compare f1 f2

Pre-patch, the server attempts a 1024-byte read, which nbdkit
rightfully rejects as going beyond its advertised 1000 byte size; the
conversion fails and the output files differ (not even the first
sector is copied, because qemu-img does not follow ddrescue's habit of
trying smaller reads to get as much information as possible in spite
of errors). Post-patch, the client's attempts to read (and query block
status, for new enough nbdkit) are properly truncated to the server's
length, with sane handling of the hole the block layer forced on
us. Although f2 ends up as a larger file (1024 bytes instead of 1000),
qemu-img compare shows the two images to have identical contents for
display to the guest.

I didn't add iotests coverage since I didn't want to add a dependency
on nbdkit in iotests. I also did NOT patch write, trim, or write
zeroes - these commands continue to fail (usually with ENOSPC, but
whatever the server chose), because we really can't write to the end
of the file, and because 'qemu-img convert' is the most common case
where we care about being tolerant (which is read-only). Perhaps we
could truncate the request if the client is writing zeros to the tail,
but that seems like more work, especially if the block layer is fixed
in 4.1 to track byte-accurate sizing (in which case this patch would
be reverted as unnecessary).

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20190329042750.14704-5-eblake@redhat.com>
Tested-by: Richard W.M. Jones <rjones@redhat.com>

The NBD spec suggests that a server should never advertise a size
inconsistent with its minimum block alignment, as that tail is
effectively inaccessible to a compliant client obeying those block
constraints. Since we have a habit of rounding up rather than
truncating, to avoid losing the last few bytes of user input, and we
cannot access the tail when the server advertises bogus block sizing,
abort the connection to alert the server to fix their bug.  And
rejecting such servers matches what we already did for a min_block
that was not a power of 2 or which was larger than max_block.

Does not impact either qemu (which always sends properly aligned
sizes) or nbdkit (which does not send minimum block requirements yet);
so this is mostly aimed at new NBD server implementations, and ensures
that the rest of our code can assume the size is aligned.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20190330155704.24191-1-eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

In usb_mask_to_str() we convert a mask of USB speeds into
a human-readable string (like "full+high") for use in
tracing and error messages. However the conversion code
doesn't do anything to the string buffer if the passed in
speedmask doesn't match any of the recognized speeds,
which means that the tracing and error messages will
end up with random garbage in them. This can happen if
we're doing USB device passthrough.

Handle the "unrecognized speed" case by using the
string "unknown".

Fixes: https://bugs.launchpad.net/qemu/+bug/1603785


Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 20190328133503.6490-1-peter.maydell@linaro.org
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

This reverts commit bd56d378.

Turned out it isn't that simple as the device needs the pit object link.
So "-device isa-pcspk" isn't going wo work anyway.  We are in freeze, so
just reverting the thing is the best way to handle this for now, trying
to come up with something better can be done in the 4.1 devel cycle.

Also add a comment noting the object link.

Reported-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Message-id: 20190328071121.21147-1-kraxel@redhat.com

It is desirable for 'qemu-img map' to have the same output for a file
whether it is served over file or nbd protocols. However, ever since
we implemented block status for NBD (2.12), the NBD protocol forgot to
inform the block layer that as the final layer in the chain, the
offset is valid; without an offset, the human-readable form of
qemu-img map gives up with the unhelpful:

$ nbdkit -U - data data="1" size=512 --run 'qemu-img map $nbd'
Offset          Length          Mapped to       File
qemu-img: File contains external, encrypted or compressed clusters.

The --output=json form always works, because it is reporting the
lower-level bdrv_block_status results directly rather than trying to
filter out sparse ranges for human consumption - but now it also
shows the offset member.

With this patch, the human output changes to:

Offset          Length          Mapped to       File
0               0x200           0               nbd+unix://?socket=/tmp/nbdkitOxeoLa/socket



This change is observable to several iotests.

Fixes: 78a33ab5
Reported-by: Richard W.M. Jones <rjones@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20190329042750.14704-4-eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

We have a latent bug in our NBD client code, tickled by the brand new
nbdkit 1.11.10 block status support:

$ nbdkit --filter=log --filter=truncate -U - \
           data data="1" size=511 truncate=64K logfile=/dev/stdout \
           --run 'qemu-img convert $nbd /var/tmp/out'
...
qemu-img: block/io.c:2122: bdrv_co_block_status: Assertion `*pnum && QEMU_IS_ALIGNED(*pnum, align) && align > offset - aligned_offset' failed.

The culprit? Our implementation of .bdrv_co_block_status can return
unaligned block status for any server that operates with a lower
actual alignment than what we tell the block layer in
request_alignment, in violation of the block layer's constraints. To
date, we've been unable to trip the bug, because qemu as NBD server
always advertises block sizing (at which point it is a server bug if
the server sends unaligned status - although qemu 3.1 is such a server
and I've sent separate patches for 4.0 both to get the server to obey
the spec, and to let the client to tolerate server oddities at EOF).

But nbdkit does not (yet) advertise block sizing, and therefore is not
in violation of the spec for returning block status at whatever
boundaries it wants, and those unaligned results can occur anywhere
rather than just at EOF. While we are still wise to avoid sending
sub-sector read/write requests to a server of unknown origin, we MUST
consider that a server telling us block status without an advertised
block size is correct.  So, we either have to munge unaligned answers
from the server into aligned ones that we hand back to the block
layer, or we have to tell the block layer about a smaller alignment.

Similarly, if the server advertises an image size that is not
sector-aligned, we might as well assume that the server intends to let
us access those tail bytes, and therefore supports a minimum block
size of 1, regardless of whether the server supports block status
(although we still need more patches to fix the problem that with an
unaligned image, we can send read or block status requests that exceed
EOF to the server). Again, qemu as server cannot trip this problem
(because it rounds images to sector alignment), but nbdkit advertised
unaligned size even before it gained block status support.

Solve both alignment problems at once by using better heuristics on
what alignment to report to the block layer when the server did not
give us something to work with. Note that very few NBD servers
implement block status (to date, only qemu and nbdkit are known to do
so); and as the NBD spec mentioned block sizing constraints prior to
documenting block status, it can be assumed that any future
implementations of block status are aware that they must advertise
block size if they want a minimum size other than 1.

We've had a long history of struggles with picking the right alignment
to use in the block layer, as evidenced by the commit message of
fd8d372d (v2.12) that introduced the current choice of forced 512-byte
alignment.

There is no iotest coverage for this fix, because qemu can't provoke
it, and I didn't want to make test 241 dependent on nbdkit.

Fixes: fd8d372d
Reported-by: Richard W.M. Jones <rjones@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20190329042750.14704-3-eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Tested-by: Richard W.M. Jones <rjones@redhat.com>

Add a test for the NBD client workaround in the previous patch.  It's
not really feasible for an iotest to assume a specific tracing engine,
so we can't really probe trace_nbd_parse_blockstatus_compliance to see
if the server was fixed vs. whether the client just worked around the
server (other than by rearranging order between code patches and this
test). But having a successful exchange sure beats the previous state
of an error message. Since format probing can change alignment, we can
use that as an easy way to test several configurations.

Not tested yet, but worth adding to this test in future patches: an
NBD server that can advertise a non-sector-aligned size (such as
nbdkit) causes qemu as the NBD client to misbehave when it rounds the
size up and accesses beyond the advertised size. Qemu as NBD server
never advertises a non-sector-aligned size (since bdrv_getlength()
currently rounds up to sector boundaries); until qemu can act as such
a server, testing that flaw will have to rely on external binaries.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20190329042750.14704-2-eblake@redhat.com>
Tested-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
[eblake: add forced-512 alignment, and nbdkit reproducer comment]

The NBD spec is clear that a server that advertises a minimum block
size should reply to NBD_CMD_BLOCK_STATUS with extents aligned
accordingly. However, we know that the qemu NBD server implementation
has had a corner-case bug where it is not compliant with the spec,
present since the introduction of NBD_CMD_BLOCK_STATUS in qemu 2.12
(and unlikely to be patched in time for 4.0). Namely, when qemu is
serving a file that is not a multiple of 512 bytes, it rounds the size
advertised over NBD up to the next sector boundary (someday, I'd like
to fix that to be byte-accurate, but it's a much bigger audit not
appropriate for this release); yet if the final sector contains data
prior to EOF, lseek(SEEK_HOLE) will point to the implicit hole
mid-sector which qemu then reported over NBD.

We are well within our rights to hang up on a server that can't follow
the spec, but it is more useful to try and keep the connection alive
in spite of the problem. Do so by tracing a message about the problem,
and then either truncating the request back to an aligned boundary (if
it covered more than the final sector) or widening it out to the full
boundary with a forced status of data (since truncating would result
in 0 bytes, but we have to make progress, and valid since data is a
default-safe answer). And in practice, since the problem only happens
on a sector that starts with data and ends with a hole, we are going
to want to read that full sector anyway (where qemu as the server
fills in the tail beyond EOF with appropriate NUL bytes).

Easy reproduction:
$ printf %1000d 1 > file
$ qemu-nbd -f raw -t file & pid=$!
$ qemu-img map --output=json -f raw nbd://localhost:10809


qemu-img: Could not read file metadata: Invalid argument
$ kill $pid

where the patched version instead succeeds with:
[{ "start": 0, "length": 1024, "depth": 0, "zero": false, "data": true}]

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20190326171317.4036-1-eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>