Make it easier to copy all the persistent bitmaps of (the top layer
of) a source image along with its guest-visible contents, by adding a
boolean flag for use with qemu-img convert. This is basically
shorthand, as the same effect could be accomplished with a series of
'qemu-img bitmap --add' and 'qemu-img bitmap --merge -b source'
commands, or by their corresponding QMP commands.
Note that this command will fail in the same scenarios where 'qemu-img
measure' omits a 'bitmaps size:' line, namely, when either the source
or the destination lacks persistent bitmap support altogether.
See also https://bugzilla.redhat.com/show_bug.cgi?id=1779893
While touching this, clean up a couple coding issues spotted in the
same function: an extra blank line, and merging back-to-back 'if
(!skip_create)' blocks.
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200521192137.1120211-5-eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
It's useful to know how much space can be occupied by qcow2 persistent
bitmaps, even though such metadata is unrelated to the guest-visible
data. Report this value as an additional QMP field, present when
measuring an existing image and output format that both support
bitmaps. Update iotest 178 and 190 to updated output, as well as new
coverage in 190 demonstrating non-zero values made possible with the
recently-added qemu-img bitmap command (see 3b51ab4b).
The new 'bitmaps size:' field is displayed automatically as part of
'qemu-img measure' any time it is present in QMP (that is, any time
both the source image being measured and destination format support
bitmaps, even if the measurement is 0 because there are no bitmaps
present). If the field is absent, it means that no bitmaps can be
copied (source, destination, or both lack bitmaps, including when
measuring based on size rather than on a source image). This behavior
is compatible with an upcoming patch adding 'qemu-img convert
--bitmaps': that command will fail in the same situations where this
patch omits the field.
The addition of a new field demonstrates why we should always
zero-initialize qapi C structs; while the qcow2 driver still fully
populates all fields, the raw and crypto drivers had to be tweaked to
avoid uninitialized data.
Consideration was also given towards having a 'qemu-img measure
--bitmaps' which errors out when bitmaps are not possible, and
otherwise sums the bitmaps into the existing allocation totals rather
than displaying as a separate field, as a potential convenience
factor. But this was ultimately decided to be more complexity than
necessary when the QMP interface was sufficient enough with bitmaps
remaining a separate field.
See also: https://bugzilla.redhat.com/1779904
Reported-by: Nir Soffer <nsoffer@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200521192137.1120211-3-eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Include actions for --add, --remove, --clear, --enable, --disable, and
--merge (note that --clear is a bit of fluff, because the same can be
accomplished by removing a bitmap and then adding a new one in its
place, but it matches what QMP commands exist). Listing is omitted,
because it does not require a bitmap name and because it was already
possible with 'qemu-img info'. A single command line can play one or
more bitmap commands in sequence on the same bitmap name (although all
added bitmaps share the same granularity, and and all merged bitmaps
come from the same source file). Merge defaults to other bitmaps in
the primary image, but can also be told to merge bitmaps from a
distinct image.
While this supports --image-opts for the file being modified, I did
not think it worth the extra complexity to support that for the source
file in a cross-file merges. Likewise, I chose to have --merge only
take a single source rather than following the QMP support for
multiple merges in one go (although you can still use more than one
--merge in the command line); in part because qemu-img is offline and
therefore atomicity is not an issue.
Upcoming patches will add iotest coverage of these commands while
also testing other features.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20200513011648.166876-7-eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
We already list the subcommand summaries alphabetically, we should do
the same for the documentation related to subcommand-specific
parameters.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20200513011648.166876-2-eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
The mapping operation of large disks especially ones stored over a
long chain of QCOW2 files can take a long time to finish.
Additionally when mapping fails there was no way recover by
restarting the mapping from the failed location.
The new options, --start-offset and --max-length allows the user to
divide these type of map operations into shorter independent tasks.
Reviewed-by: Eric Blake <eblake@redhat.com>
Acked-by: Mark Kanda <mark.kanda@oracle.com>
Co-developed-by: Yoav Elnekave <yoav.elnekave@oracle.com>
Signed-off-by: Yoav Elnekave <yoav.elnekave@oracle.com>
Signed-off-by: Eyal Moscovici <eyal.moscovici@oracle.com>
Message-Id: <20200513133629.18508-5-eyal.moscovici@oracle.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
Move the following tools documentation files to the new tools manual:
docs/interop/qemu-img.rst
docs/interop/qemu-nbd.rst
docs/interop/virtfs-proxy-helper.rst
docs/interop/qemu-trace-stap.rst
docs/interop/virtiofsd.rst
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 20200217155415.30949-4-peter.maydell@linaro.org
Some of the documentation for QEMU "tools" which are standalone
binaries like qemu-img is an awkward fit in our current 5-manual
split. We've put it into "interop", but they're not really
about interoperability.
Create a new top level manual "tools" which will be a better
home for this documentation. This commit creates an empty
initial manual; we will move the relevant documentation
files in a subsequent commit.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 20200217155415.30949-2-peter.maydell@linaro.org
