Merge tag 'pull-nbd-2023-10-05' of https://repo.or.cz/qemu/ericb into staging

NBD patches for 2023-10-05

- various: mailmap cleanups
- Eric Blake: enable use of NBD 64-bit extended headers

# -----

Merge tag 'pull-nbd-2023-10-05' of https://repo.or.cz/qemu/ericb into staging

NBD patches for 2023-10-05

- various: mailmap cleanups
- Eric Blake: enable use of NBD 64-bit extended headers

# -----BEGIN PGP SIGNATURE-----
#
# iQEzBAABCAAdFiEEccLMIrHEYCkn0vOqp6FrSiUnQ2oFAmUfA94ACgkQp6FrSiUn
# Q2o2hAf/Q4q6RoEG9WoOIa6WB1nk9tZN6GRfW4jS+09hJTFVbYUhJOcvQwwZjPT6
# 6oIwde8w7uE+AxBOA3XPbgTOBnTnpt2RH2AYVctNYB2vonuSrx3/KE3XSi4nrJRo
# +XiPbOsDzQu+vYsI7XJ+5e13BE4iZVmzbyke0U6hO88uR6tQstDJV1Mhem4jIbCG
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# SU66lXL/5jM9N7RkiSFwvupaot9hvw==
# =UieX
# -----END PGP SIGNATURE-----
# gpg: Signature made Thu 05 Oct 2023 14:43:42 EDT
# gpg: using RSA key 71C2CC22B1C4602927D2F3AAA7A16B4A2527436A
# 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

* tag 'pull-nbd-2023-10-05' of https://repo.or.cz/qemu/ericb:
nbd/server: Add FLAG_PAYLOAD support to CMD_BLOCK_STATUS
nbd/server: Prepare for per-request filtering of BLOCK_STATUS
nbd/server: Refactor list of negotiated meta contexts
nbd/client: Request extended headers during negotiation
nbd/client: Accept 64-bit block status chunks
nbd/client: Initial support for extended headers
nbd/client: Plumb errp through nbd_receive_replies
nbd/server: Enable initial support for extended headers
nbd/server: Support 64-bit block status
nbd/server: Prepare to send extended header replies
nbd/server: Prepare to receive extended header requests
nbd/server: Support a request payload
mailmap: Fix BALATON Zoltan author email
maint: Tweak comments in mailmap regarding SPF
mailmap: Fix Andrey Drobyshev author email

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

show more ...

nbd/client: Request extended headers during negotiation

All the pieces are in place for a client to finally request extended
headers. Note that we must not request extended headers when qemu-nbd
is

nbd/client: Request extended headers during negotiation

All the pieces are in place for a client to finally request extended
headers. Note that we must not request extended headers when qemu-nbd
is used to connect to the kernel module (as nbd.ko does not expect
them, but expects us to do the negotiation in userspace before handing
the socket over to the kernel), but there is no harm in all other
clients requesting them.

Extended headers are not essential to the information collected during
'qemu-nbd --list', but probing for it gives us one more piece of
information in that output. Update the iotests affected by the new
line of output.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Message-ID: <20230925192229.3186470-23-eblake@redhat.com>

show more ...

Merge tag 'for-upstream' of https://repo.or.cz/qemu/kevin into staging

Block layer patches

- Graph locking part 4 (node management)
- qemu-img map: report compressed data blocks
- block-backend: pr

Merge tag 'for-upstream' of https://repo.or.cz/qemu/kevin into staging

Block layer patches

- Graph locking part 4 (node management)
- qemu-img map: report compressed data blocks
- block-backend: process I/O in the current AioContext

# -----BEGIN PGP SIGNATURE-----
#
# iQJFBAABCAAvFiEE3D3rFZqa+V09dFb+fwmycsiPL9YFAmULHnURHGt3b2xmQHJl
# ZGhhdC5jb20ACgkQfwmycsiPL9aB5hAAqH8To7WIUtg1rj1PY809ck78ghm18PKg
# TNdN7IbrXQghX5foh2VgPwVVl+JaW2CSrJYWQcAO6AbvFduNIi9iKzI6RT0xKXpb
# b8oQXS7zntFzwBv8ohOU5NSVJOgVmNP4h5qJIMmXgB9ZcLFG40zggVH2qQT7guUf
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# 4PzuL4UI21ik2zieO1qVM+Thqvw16kHtp6dD9pGk4X4ogGreGYEIxzBl79luR+AV
# NCRizoeFWTHKymS1tSoKrWT9ZNHcLmwemO6Tt1rMYk9jV3T4uY5e1NwxaUavEfsX
# f8dLfQjhNiySOoDknT1OSerBOVdTXURS2ri5H3GZxrxvJ4jOeFkn52C8r3YlZ3Wp
# Cr9LCUJZeXgwY+Q1JQ3D4VLY8aZ83txpw6XKEy0eTEv5wxkBj5LWhXx7hNb5F3lg
# bqaRYijVJn+P82wVxlftIzMfNeVBFHzFE90taPV5grJjr8lgrGBFmD7Puc97kfDX
# oTDBwRxJeew=
# =qTNA
# -----END PGP SIGNATURE-----
# gpg: Signature made Wed 20 Sep 2023 12:31:49 EDT
# gpg: using RSA key DC3DEB159A9AF95D3D7456FE7F09B272C88F2FD6
# gpg: issuer "kwolf@redhat.com"
# gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>" [full]
# Primary key fingerprint: DC3D EB15 9A9A F95D 3D74 56FE 7F09 B272 C88F 2FD6

* tag 'for-upstream' of https://repo.or.cz/qemu/kevin: (28 commits)
block: mark aio_poll as non-coroutine
block-backend: process zoned requests in the current AioContext
block-backend: process I/O in the current AioContext
test-bdrv-drain: avoid race with BH in IOThread drain test
block: remove AIOCBInfo->get_aio_context()
qemu-img: map: report compressed data blocks
block: add BDRV_BLOCK_COMPRESSED flag for bdrv_block_status()
block: Mark bdrv_add/del_child() and caller GRAPH_WRLOCK
block: Mark bdrv_unref_child() GRAPH_WRLOCK
block: Mark bdrv_root_unref_child() GRAPH_WRLOCK
block: Take graph rdlock in bdrv_change_aio_context()
block: Take graph rdlock in bdrv_drop_intermediate()
block: Mark bdrv_parent_cb_change_media() GRAPH_RDLOCK
block: Mark bdrv_child_perm() GRAPH_RDLOCK
block: Mark bdrv_get_cumulative_perm() and callers GRAPH_RDLOCK
block: Mark bdrv_parent_perms_conflict() and callers GRAPH_RDLOCK
block: Mark bdrv_attach_child() GRAPH_WRLOCK
block: Call transaction callbacks with lock held
block: Mark bdrv_attach_child_common() GRAPH_WRLOCK
block: Mark bdrv_replace_child_tran() GRAPH_WRLOCK
...

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

show more ...

qemu-img: map: report compressed data blocks

Right now "qemu-img map" reports compressed blocks as containing data
but having no host offset. This is not very informative. Instead,
let's add anoth

qemu-img: map: report compressed data blocks

Right now "qemu-img map" reports compressed blocks as containing data
but having no host offset. This is not very informative. Instead,
let's add another boolean field named "compressed" in case JSON output
mode is specified. This is achieved by utilizing new allocation status
flag BDRV_BLOCK_COMPRESSED for bdrv_block_status().

Also update the expected qemu-iotests outputs to contain the new field.

Signed-off-by: Andrey Drobyshev <andrey.drobyshev@virtuozzo.com>
Message-ID: <20230907210226.953821-3-andrey.drobyshev@virtuozzo.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

show more ...

Merge remote-tracking branch 'remotes/ericb/tags/pull-nbd-2022-03-07' into staging

nbd patches for 2022-03-07

- Dan Berrange: Allow qemu-nbd to support TLS over Unix sockets
- Eric Blake: Minor cle

Merge remote-tracking branch 'remotes/ericb/tags/pull-nbd-2022-03-07' into staging

nbd patches for 2022-03-07

- Dan Berrange: Allow qemu-nbd to support TLS over Unix sockets
- Eric Blake: Minor cleanups related to 64-bit block operations

# gpg: Signature made Tue 08 Mar 2022 01:41:35 GMT
# gpg: using RSA key 71C2CC22B1C4602927D2F3AAA7A16B4A2527436A
# 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-2022-03-07:
qemu-io: Allow larger write zeroes under no fallback
qemu-io: Utilize 64-bit status during map
nbd/server: Minor cleanups
tests/qemu-iotests: validate NBD TLS with UNIX sockets and PSK
tests/qemu-iotests: validate NBD TLS with UNIX sockets
tests/qemu-iotests: validate NBD TLS with hostname mismatch
tests/qemu-iotests: convert NBD TLS test to use standard filters
tests/qemu-iotests: introduce filter for qemu-nbd export list
tests/qemu-iotests: expand _filter_nbd rules
tests/qemu-iotests: add QEMU_IOTESTS_REGEN=1 to update reference file
block/nbd: don't restrict TLS usage to IP sockets
qemu-nbd: add --tls-hostname option for TLS certificate validation
block/nbd: support override of hostname for TLS certificate validation
block: pass desired TLS hostname through from block driver client
crypto: mandate a hostname when checking x509 creds on a client

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

show more ...

tests/qemu-iotests: introduce filter for qemu-nbd export list

Introduce a filter for the output of qemu-nbd export list so it can be
reused in multiple tests.

The filter is a bit more permissive th

tests/qemu-iotests: introduce filter for qemu-nbd export list

Introduce a filter for the output of qemu-nbd export list so it can be
reused in multiple tests.

The filter is a bit more permissive that what test 241 currently uses,
as its allows printing of the export count, along with any possible
error messages that might be emitted.

Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20220304193610.3293146-9-berrange@redhat.com>
Tested-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>

show more ...

Merge remote-tracking branch 'remotes/ericb/tags/pull-nbd-2021-07-09-v2' into staging

nbd patches for 2021-07-09

- enhance 'qemu-img map --output=json' to make it easier to duplicate
backing chain

Merge remote-tracking branch 'remotes/ericb/tags/pull-nbd-2021-07-09-v2' into staging

nbd patches for 2021-07-09

- enhance 'qemu-img map --output=json' to make it easier to duplicate
backing chain allocation patterns
- fix a race in the 'yank' QMP command in relation to NBD requests

# gpg: Signature made Mon 12 Jul 2021 18:43:37 BST
# gpg: using RSA key 71C2CC22B1C4602927D2F3AAA7A16B4A2527436A
# 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-2021-07-09-v2:
nbd: register yank function earlier
qemu-img: Reword 'qemu-img map --output=json' docs
qemu-img: Make unallocated part of backing chain obvious in map
iotests: Improve and rename test 309 to nbd-qemu-allocation

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

show more ...

qemu-img: Make unallocated part of backing chain obvious in map

The recently-added NBD context qemu:allocation-depth is able to
distinguish between locally-present data (even when that data is
spars

qemu-img: Make unallocated part of backing chain obvious in map

The recently-added NBD context qemu:allocation-depth is able to
distinguish between locally-present data (even when that data is
sparse) [shown as depth 1 over NBD], and data that could not be found
anywhere in the backing chain [shown as depth 0]; and the libnbd
project was recently patched to give the human-readable name "absent"
to an allocation-depth of 0. But qemu-img map --output=json predates
that addition, and has the unfortunate behavior that all portions of
the backing chain that resolve without finding a hit in any backing
layer report the same depth as the final backing layer. This makes it
harder to reconstruct a qcow2 backing chain using just 'qemu-img map'
output, especially when using "backing":null to artificially limit a
backing chain, because it is impossible to distinguish between a
QCOW2_CLUSTER_UNALLOCATED (which defers to a [missing] backing file)
and a QCOW2_CLUSTER_ZERO_PLAIN cluster (which would override any
backing file), since both types of clusters otherwise show as
"data":false,"zero":true" (but note that we can distinguish a
QCOW2_CLUSTER_ZERO_ALLOCATED, which would also have an "offset":
listing).

The task of reconstructing a qcow2 chain was made harder in commit
0da9856851 (nbd: server: Report holes for raw images), because prior
to that point, it was possible to abuse NBD's block status command to
see which portions of a qcow2 file resulted in BDRV_BLOCK_ALLOCATED
(showing up as NBD_STATE_ZERO in isolation) vs. missing from the chain
(showing up as NBD_STATE_ZERO|NBD_STATE_HOLE); but now qemu reports
more accurate sparseness information over NBD.

An obvious solution is to make 'qemu-img map --output=json' add an
additional "present":false designation to any cluster lacking an
allocation anywhere in the chain, without any change to the "depth"
parameter to avoid breaking existing clients. The iotests have
several examples where this distinction demonstrates the additional
accuracy.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20210701190655.2131223-3-eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
[eblake: fix more iotest fallout]
Signed-off-by: Eric Blake <eblake@redhat.com>

show more ...

Merge remote-tracking branch 'remotes/ericb/tags/pull-nbd-2021-03-09' into staging

nbd patches for 2021-03-09

- Add Vladimir as NBD co-maintainer
- Fix reporting of holes in NBD_CMD_BLOCK_STATUS
-

Merge remote-tracking branch 'remotes/ericb/tags/pull-nbd-2021-03-09' into staging

nbd patches for 2021-03-09

- Add Vladimir as NBD co-maintainer
- Fix reporting of holes in NBD_CMD_BLOCK_STATUS
- Improve command-line parsing accuracy of large numbers (anything going
through qemu_strtosz), including the deprecation of hex+suffix
- Improve some error reporting in the block layer

# gpg: Signature made Tue 09 Mar 2021 15:38:10 GMT
# gpg: using RSA key 71C2CC22B1C4602927D2F3AAA7A16B4A2527436A
# 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-2021-03-09:
block/qcow2: refactor qcow2_update_options_prepare error paths
block/qed: bdrv_qed_do_open: deal with errp
block/qcow2: simplify qcow2_co_invalidate_cache()
block/qcow2: read_cache_sizes: return status value
block/qcow2-bitmap: return status from qcow2_store_persistent_dirty_bitmaps
block/qcow2-bitmap: improve qcow2_load_dirty_bitmaps() interface
block/qcow2: qcow2_get_specific_info(): drop error propagation
blockjob: return status from block_job_set_speed()
block/mirror: drop extra error propagation in commit_active_start()
block: drop extra error propagation for bdrv_set_backing_hd
blockdev: fix drive_backup_prepare() missed error
block: check return value of bdrv_open_child and drop error propagation
utils: Deprecate hex-with-suffix sizes
utils: Improve qemu_strtosz() to have 64 bits of precision
utils: Enhance testsuite for do_strtosz()
nbd: server: Report holes for raw images
MAINTAINERS: add Vladimir as co-maintainer of NBD

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

show more ...

nbd: server: Report holes for raw images

When querying image extents for raw image, qemu-nbd reports holes as
zero:

$ qemu-nbd -t -r -f raw empty-6g.raw

$ qemu-img map --output json nbd://localhos

nbd: server: Report holes for raw images

When querying image extents for raw image, qemu-nbd reports holes as
zero:

$ qemu-nbd -t -r -f raw empty-6g.raw

$ qemu-img map --output json nbd://localhost
[{ "start": 0, "length": 6442450944, "depth": 0, "zero": true, "data": true, "offset": 0}]

$ qemu-img map --output json empty-6g.raw
[{ "start": 0, "length": 6442450944, "depth": 0, "zero": true, "data": false, "offset": 0}]

Turns out that qemu-img map reports a hole based on BDRV_BLOCK_DATA, but
nbd server reports a hole based on BDRV_BLOCK_ALLOCATED.

The NBD protocol says:

NBD_STATE_HOLE (bit 0): if set, the block represents a hole (and
future writes to that area may cause fragmentation or encounter an
NBD_ENOSPC error); if clear, the block is allocated or the server
could not otherwise determine its status.

qemu-img manual says:

whether the sectors contain actual data or not (boolean field data;
if false, the sectors are either unallocated or stored as
optimized all-zero clusters);

To me, data=false looks compatible with NBD_STATE_HOLE. From user point
of view, getting same results from qemu-nbd and qemu-img is more
important than being more correct about allocation status.

Changing nbd server to report holes using BDRV_BLOCK_DATA makes qemu-nbd
results compatible with qemu-img map:

$ qemu-img map --output json nbd://localhost
[{ "start": 0, "length": 6442450944, "depth": 0, "zero": true, "data": false, "offset": 0}]

Signed-off-by: Nir Soffer <nsoffer@redhat.com>
Message-Id: <20210219160752.1826830-1-nsoffer@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Eric Blake <eblake@redhat.com>

show more ...

Merge remote-tracking branch 'remotes/kevin/tags/for-upstream' into staging

Block layer patches:

- iotests fixes

# gpg: Signature made Fri 12 Apr 2019 17:04:09 BST
# gpg: using RSA

Merge remote-tracking branch 'remotes/kevin/tags/for-upstream' into staging

Block layer patches:

- iotests fixes

# gpg: Signature made Fri 12 Apr 2019 17:04:09 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:
iotest: Fix 241 to run in generic directory
iotests: Let 245 pass on tmpfs

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

show more ...

iotest: Fix 241 to run in generic directory

Filter the qemu-nbd server output to get rid of a direct reference
to my build directory.

Fixes: e9dce9cb
Reported-by: Max Reitz <mreitz@redhat.com>
Sign

iotest: Fix 241 to run in generic directory

Filter the qemu-nbd server output to get rid of a direct reference
to my build directory.

Fixes: e9dce9cb
Reported-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

show more ...

Merge remote-tracking branch 'remotes/ericb/tags/pull-nbd-2019-04-01' into staging

nbd patches for 2019-04-01

- Better behavior of qemu-img map on NBD images
- Fixes for NBD protocol alignment corn

Merge remote-tracking branch 'remotes/ericb/tags/pull-nbd-2019-04-01' into staging

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>

show more ...

nbd/server: Advertise actual minimum block size

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 re

nbd/server: Advertise actual minimum block size

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]

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nbd/client: Report offsets in bdrv_block_status

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 implemen

nbd/client: Report offsets in bdrv_block_status

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>

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iotests: Add 241 to test NBD on unaligned images

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 ca

iotests: Add 241 to test NBD on unaligned images

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]

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