qemu/qapi
Kevin Wolf 4af976ef39 rbd: Fix .bdrv_get_specific_info implementation
qemu_rbd_get_specific_info() has at least two problems:

The first is that it issues a blocking rbd_read() call in order to probe
the encryption format for the image while querying the node. This means
that if the connection to the server goes down, not only I/O is stuck
(which is unavoidable), but query-names-block-nodes will actually make
the whole QEMU instance unresponsive. .bdrv_get_specific_info
implementations shouldn't perform blocking operations, but only return
what is already known.

The second is that the information returned isn't even correct. If the
image is already opened with encryption enabled at the RBD level, we'll
probe for "double encryption", i.e. if the encrypted data contains
another encryption header. If it doesn't (which is the normal case), we
won't return the encryption format. If it does, we return misleading
information because it looks like we're talking about the outer level
(the encryption format of the image itself) while the information is
about an encryption header in the guest data.

Fix this by storing the encryption format in BDRVRBDState when the image
is opened (and we do blocking operations anyway) and returning only the
stored information in qemu_rbd_get_specific_info().

The information we'll store is either the actual encryption format that
we enabled on the RBD level, or if the image is unencrypted, the result
of the same probing as we previously did when querying the node. Probing
image formats based on content that can be modified by the guest has
long been known as problematic, but as long as we only output it to the
user instead of making decisions based on it, it should be okay. It is
undoubtedly useful in the context of 'qemu-img info' when you're trying
to figure out which encryption options you have to use to open the
image successfully.

Fixes: 42e4ac9ef5 ("block/rbd: Add support for rbd image encryption")
Buglink: https://issues.redhat.com/browse/RHEL-105440
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-ID: <20250811134010.81787-1-kwolf@redhat.com>
Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2025-08-12 14:59:39 +02:00
..
accelerator.json qapi/accelerator: Fix markup of heading 2025-07-29 14:51:39 +02:00
acpi.json qapi: add cross-references to acpi.json 2025-07-14 12:52:46 +02:00
audio.json qapi: remove trivial "Returns:" sections 2025-07-14 12:35:29 +02:00
authz.json qapi: add cross-references to authz.json 2025-07-14 12:52:46 +02:00
block-core.json rbd: Fix .bdrv_get_specific_info implementation 2025-08-12 14:59:39 +02:00
block-export.json qapi: add cross-references to block layer 2025-07-14 12:55:17 +02:00
block.json qapi: add cross-references to block layer 2025-07-14 12:55:17 +02:00
char.json qapi: remove trivial "Returns:" sections 2025-07-14 12:35:29 +02:00
common.json docs/sphinx: remove special parsing for freeform sections 2025-07-14 10:08:27 +02:00
compat.json docs/sphinx: remove special parsing for freeform sections 2025-07-14 10:08:27 +02:00
control.json qapi: add cross-references to misc modules 2025-07-14 12:58:13 +02:00
crypto.json qapi: add cross-references to crypto.json 2025-07-14 12:55:49 +02:00
cryptodev.json qapi: remove trivial "Returns:" sections 2025-07-14 12:35:29 +02:00
cxl.json docs/sphinx: remove special parsing for freeform sections 2025-07-14 10:08:27 +02:00
dump.json qapi: Add more cross-references 2025-07-29 14:51:20 +02:00
ebpf.json qapi: add cross-references to misc modules 2025-07-14 12:58:13 +02:00
error.json docs/sphinx: remove special parsing for freeform sections 2025-07-14 10:08:27 +02:00
introspect.json qapi: add cross-references to misc modules 2025-07-14 12:58:13 +02:00
job.json qapi: add cross-references to job.json 2025-07-14 12:57:27 +02:00
machine-common.json qapi: add cross-references to Machine core 2025-07-14 12:58:13 +02:00
machine-s390x.json qapi: make s390x specific CPU commands unconditionally available 2025-05-28 18:56:08 +02:00
machine.json qapi: Add more cross-references 2025-07-29 14:51:20 +02:00
meson.build qapi/accel: Move definitions related to accelerators in their own file 2025-07-15 19:28:02 +02:00
migration.json qapi: Add more cross-references 2025-07-29 14:51:20 +02:00
misc-arm.json qapi: add cross-references to misc modules 2025-07-14 12:58:13 +02:00
misc-i386.json qapi: Add more cross-references 2025-07-29 14:51:20 +02:00
misc.json qapi: add cross-references to misc modules 2025-07-14 12:58:13 +02:00
net.json QAPI patches patches for 2025-07-14 2025-07-16 07:07:30 -04:00
opts-visitor.c qapi: Inline and remove QERR_INVALID_PARAMETER definition 2024-04-24 09:50:58 +02:00
pci.json qapi: add cross-references to pci.json 2025-07-14 12:58:13 +02:00
pragma.json qapi: Document QCryptodevBackendServiceType 2024-10-02 09:10:01 +02:00
qapi-clone-visitor.c qapi: Move include/qapi/qmp/ to include/qobject/ 2025-02-10 15:33:16 +01:00
qapi-dealloc-visitor.c qapi: Move include/qapi/qmp/ to include/qobject/ 2025-02-10 15:33:16 +01:00
qapi-forward-visitor.c qapi: change 'unsigned special_features' to 'uint64_t features' 2025-02-10 15:45:04 +01:00
qapi-schema.json Accelerators patches 2025-07-16 07:13:40 -04:00
qapi-type-helpers.c qapi: New strv_from_str_list() 2024-03-04 07:12:40 +01:00
qapi-util.c qapi: change 'unsigned special_features' to 'uint64_t features' 2025-02-10 15:45:04 +01:00
qapi-visit-core.c qapi: change 'unsigned special_features' to 'uint64_t features' 2025-02-10 15:45:04 +01:00
qdev.json qapi: add cross-references to QOM 2025-07-14 12:58:13 +02:00
qmp-dispatch.c qapi: change 'unsigned special_features' to 'uint64_t features' 2025-02-10 15:45:04 +01:00
qmp-event.c qapi: Move include/qapi/qmp/ to include/qobject/ 2025-02-10 15:33:16 +01:00
qmp-registry.c qapi: change 'unsigned special_features' to 'uint64_t features' 2025-02-10 15:45:04 +01:00
qobject-input-visitor.c qapi: change 'unsigned special_features' to 'uint64_t features' 2025-02-10 15:45:04 +01:00
qobject-output-visitor.c qapi: change 'unsigned special_features' to 'uint64_t features' 2025-02-10 15:45:04 +01:00
qom.json qom: qom-list-get 2025-07-16 16:51:21 +02:00
replay.json qapi: add cross-references to replay.json 2025-07-14 12:58:13 +02:00
rocker.json qapi: remove trivial "Returns:" sections 2025-07-14 12:35:29 +02:00
run-state.json qapi: Add more cross-references 2025-07-29 14:51:20 +02:00
sockets.json qapi: Add more cross-references 2025-07-29 14:51:20 +02:00
stats.json qapi: add cross-references to misc modules 2025-07-14 12:58:13 +02:00
string-input-visitor.c qapi: Move include/qapi/qmp/ to include/qobject/ 2025-02-10 15:33:16 +01:00
string-output-visitor.c string-output-visitor: Fix (pseudo) struct handling 2024-01-26 11:16:58 +01:00
tpm.json qapi: remove trivial "Returns:" sections 2025-07-14 12:35:29 +02:00
trace-events qapi: Generalize struct member policy checking 2021-10-29 18:23:09 +02:00
trace.h trace: switch position of headers to what Meson requires 2020-08-21 06:18:24 -04:00
trace.json qapi: rephrase return docs to avoid type name 2025-07-14 12:35:39 +02:00
transaction.json qapi: add cross-references to block layer 2025-07-14 12:55:17 +02:00
uefi.json docs/sphinx: remove special parsing for freeform sections 2025-07-14 10:08:27 +02:00
ui.json QAPI patches patches for 2025-07-14 2025-07-16 07:07:30 -04:00
vfio.json docs/sphinx: remove special parsing for freeform sections 2025-07-14 10:08:27 +02:00
virtio.json QAPI patches patches for 2025-07-14 2025-07-16 07:07:30 -04:00
yank.json qapi: add cross-references to yank.json 2025-07-14 12:58:13 +02:00