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

Block layer patches

- Make blockdev-reopen stable
- Remove deprecated qemu-img backing file without format
- rbd: Convert

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

Block layer patches

- Make blockdev-reopen stable
- Remove deprecated qemu-img backing file without format
- rbd: Convert to coroutines and add write zeroes support
- rbd: Updated MAINTAINERS
- export/fuse: Allow other users access to the export
- vhost-user: Fix backends without multiqueue support
- Fix drive-backup transaction endless drained section

# gpg: Signature made Fri 09 Jul 2021 13:49:22 BST
# 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

* remotes/kevin/tags/for-upstream: (28 commits)
block: Make blockdev-reopen stable API
iotests: Test reopening multiple devices at the same time
block: Support multiple reopening with x-blockdev-reopen
block: Acquire AioContexts during bdrv_reopen_multiple()
block: Add bdrv_reopen_queue_free()
qcow2: Fix dangling pointer after reopen for 'file'
qemu-img: Improve error for rebase without backing format
qemu-img: Require -F with -b backing image
qcow2: Prohibit backing file changes in 'qemu-img amend'
blockdev: fix drive-backup transaction endless drained section
vhost-user: Fix backends without multiqueue support
MAINTAINERS: add block/rbd.c reviewer
block/rbd: fix type of task->complete
iotests/fuse-allow-other: Test allow-other
iotests/308: Test +w on read-only FUSE exports
export/fuse: Let permissions be adjustable
export/fuse: Give SET_ATTR_SIZE its own branch
export/fuse: Add allow-other option
export/fuse: Pass default_permissions for mount
util/uri: do not check argument of uri_free()
...

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

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qemu-img: Require -F with -b backing image

Back in commit d9f059aa6c (qemu-img: Deprecate use of -b without -F),
we deprecated the ability to create a file with a backing image that
requires qemu to

qemu-img: Require -F with -b backing image

Back in commit d9f059aa6c (qemu-img: Deprecate use of -b without -F),
we deprecated the ability to create a file with a backing image that
requires qemu to perform format probing. Qemu can still probe older
files for backwards compatibility, but it is time to finish off the
ability to create such images, due to the potential security risk they
present. Update a couple of iotests affected by the change.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20210503213600.569128-3-eblake@redhat.com>
Reviewed-by: Connor Kuehl <ckuehl@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

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

Block layer patches:

- file-posix: Mitigate file fragmentation with extent size hints
- Tighten qemu-img rules on missing

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

Block layer patches:

- file-posix: Mitigate file fragmentation with extent size hints
- Tighten qemu-img rules on missing backing format
- qemu-img map: Don't limit block status request size
- Fix crash with virtio-scsi and iothreads

# gpg: Signature made Tue 14 Jul 2020 14:24:19 BST
# 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

* remotes/kevin/tags/for-upstream:
block: Avoid stale pointer dereference in blk_get_aio_context()
qemu-img: Deprecate use of -b without -F
block: Add support to warn on backing file change without format
iotests: Specify explicit backing format where sensible
qcow2: Deprecate use of qemu-img amend to change backing file
block: Error if backing file fails during creation without -u
qcow: Tolerate backing_fmt=
vmdk: Add trivial backing_fmt support
sheepdog: Add trivial backing_fmt support
block: Finish deprecation of 'qemu-img convert -n -o'
qemu-img: Flush stdout before before potential stderr messages
file-posix: Mitigate file fragmentation with extent size hints
iotests/059: Filter out disk size with more standard filter
qemu-img map: Don't limit block status request size
iotests: Simplify _filter_img_create() a bit

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

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qemu-img: Deprecate use of -b without -F

Creating an image that requires format probing of the backing image is
potentially unsafe (we've had several CVEs over the years based on
probes leaking info

qemu-img: Deprecate use of -b without -F

Creating an image that requires format probing of the backing image is
potentially unsafe (we've had several CVEs over the years based on
probes leaking information to the guest on a subsequent boot, although
these days tools like libvirt are aware of the issue enough to prevent
the worst effects). For example, if our probing algorithm ever
changes, or if other tools like libvirt determine a different probe
result than we do, then subsequent use of that backing file under a
different format will present corrupted data to the guest.
Fortunately, the worst effects occur only when the backing image is
originally raw, and we at least prevent commit into a probed raw
backing file that would change its probed type.

Still, it is worth starting a deprecation clock so that future
qemu-img can refuse to create backing chains that would rely on
probing, to encourage clients to avoid unsafe practices. Most
warnings are intentionally emitted from bdrv_img_create() in the block
layer, but qemu-img convert uses bdrv_create() which cannot emit its
own warning without causing spurious warnings on other code paths. In
the end, all command-line image creation or backing file rewriting now
performs a check.

Furthermore, if we probe a backing file as non-raw, then it is safe to
explicitly record that result (rather than relying on future probes);
only where we probe a raw image do we care about further warnings to
the user when using such an image (for example, commits into a
probed-raw backing file are prevented), to help them improve their
tooling. But whether or not we make the probe results explicit, we
still warn the user to remind them to upgrade their workflow to supply
-F always.

iotest 114 specifically wants to create an unsafe image for later
amendment rather than defaulting to our new default of recording a
probed format, so it needs an update. While touching it, expand it to
cover all of the various warnings enabled by this patch. iotest 301
also shows a change to qcow messages.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200706203954.341758-11-eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

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block: Error if backing file fails during creation without -u

Back in commit 6e6e55f5 (Jul 2017, v2.10), we tweaked the code to warn
if the backing file could not be opened but the user gave a size,

block: Error if backing file fails during creation without -u

Back in commit 6e6e55f5 (Jul 2017, v2.10), we tweaked the code to warn
if the backing file could not be opened but the user gave a size,
unless the user also passes the -u option to bypass the open of the
backing file. As one common reason for failure to open the backing
file is when there is mismatch in the requested backing format in
relation to what the backing file actually contains, we actually want
to open the backing file and ensure that it has the right format in as
many cases as possible. iotest 301 for qcow demonstrates how
detecting explicit format mismatch is useful to prevent the creation
of an image that would probe differently than the user requested. Now
is the time to finally turn the warning an error, as promised.

Note that the original warning was added prior to our documentation of
an official deprecation policy (eb22aeca, also Jul 2017), and because
the warning didn't mention the word "deprecated", we never actually
remembered to document it as such. But the warning has been around
long enough that I don't see prolonging it another two releases.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200706203954.341758-7-eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

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qcow: Tolerate backing_fmt=

qcow has no space in the metadata to store a backing format, and there
are existing qcow images backed both by raw or by other formats
(usually qcow) images, reliant on p

qcow: Tolerate backing_fmt=

qcow has no space in the metadata to store a backing format, and there
are existing qcow images backed both by raw or by other formats
(usually qcow) images, reliant on probing to tell the difference. On
the bright side, because we probe every time, raw files are marked as
probed and we thus forbid a commit action into the backing file where
guest-controlled contents could change the result of the probe next
time around (the iotest added here proves that).

Still, allowing the user to specify the backing format during
creation, even if we can't record it, is a good thing. This patch
blindly allows any value that resolves to a known driver, even if the
user's request is a mismatch from what probing finds; then the next
patch will further enhance things to verify that the user's request
matches what we actually probe. With this and the next patch in
place, we will finally be ready to deprecate the creation of images
where a backing format was not explicitly specified by the user.

Note that this is only for QemuOpts usage; there is no change to the
QAPI to allow a format through -blockdev.

Add a new iotest 301 just for qcow, to demonstrate the latest
behavior, and to make it easier to show the improvements made in the
next patch.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200706203954.341758-6-eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

show more ...