If we rebase an image whose backing file has compressed clusters, we
might end up wasting disk space since the copied clusters are now
uncompressed. In order to have better control over this, let's add
"--compress" option to the "qemu-img rebase" command.
Note that this option affects only the clusters which are actually being
copied from the original backing file. The clusters which were
uncompressed in the target image will remain so.
Signed-off-by: Andrey Drobyshev <andrey.drobyshev@virtuozzo.com>
Reviewed-by: Denis V. Lunev <den@openvz.org>
Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
Message-ID: <20230919165804.439110-8-andrey.drobyshev@virtuozzo.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
As recent CVE-2023-2861 (fixed by f6b0de53fb) once again showed, the 9p
'proxy' fs driver is in bad shape. Using the 'proxy' backend was already
discouraged for safety reasons before and we recommended to use the
'local' backend (preferably in conjunction with its 'mapped' security
model) instead, but now it is time to officially deprecate the 'proxy'
backend.
Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
Message-Id: <E1qDkmw-0007M1-8f@lizzy.crudebyte.com>
Remove all the virtiofsd build and docs infrastructure.
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Currently we use 'id' option as the name of VDUSE device.
It's a bit confusing since we use one value for two different
purposes: the ID to identfy the export within QEMU (must be
distinct from any other exports in the same QEMU process, but
can overlap with names used by other processes), and the VDUSE
name to uniquely identify it on the host (must be distinct from
other VDUSE devices on the same host, but can overlap with other
export types like NBD in the same process). To make it clear,
this patch adds a separate 'name' option to specify the VDUSE
name for the vduse-blk export instead.
Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
Message-Id: <20220614051532.92-7-xieyongji@bytedance.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
According to the NBD spec, a server that advertises
NBD_FLAG_CAN_MULTI_CONN promises that multiple client connections will
not see any cache inconsistencies: when properly separated by a single
flush, actions performed by one client will be visible to another
client, regardless of which client did the flush.
We always satisfy these conditions in qemu - even when we support
multiple clients, ALL clients go through a single point of reference
into the block layer, with no local caching. The effect of one client
is instantly visible to the next client. Even if our backend were a
network device, we argue that any multi-path caching effects that
would cause inconsistencies in back-to-back actions not seeing the
effect of previous actions would be a bug in that backend, and not the
fault of caching in qemu. As such, it is safe to unconditionally
advertise CAN_MULTI_CONN for any qemu NBD server situation that
supports parallel clients.
Note, however, that we don't want to advertise CAN_MULTI_CONN when we
know that a second client cannot connect (for historical reasons,
qemu-nbd defaults to a single connection while nbd-server-add and QMP
commands default to unlimited connections; but we already have
existing means to let either style of NBD server creation alter those
defaults). This is visible by no longer advertising MULTI_CONN for
'qemu-nbd -r' without -e, as in the iotest nbd-qemu-allocation.
The harder part of this patch is setting up an iotest to demonstrate
behavior of multiple NBD clients to a single server. It might be
possible with parallel qemu-io processes, but I found it easier to do
in python with the help of libnbd, and help from Nir and Vladimir in
writing the test.
Signed-off-by: Eric Blake <eblake@redhat.com>
Suggested-by: Nir Soffer <nsoffer@redhat.com>
Suggested-by: Vladimir Sementsov-Ogievskiy <v.sementsov-og@mail.ru>
Message-Id: <20220512004924.417153-3-eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Simple grep for the .bdrv_co_check callback presence gives the following
list of block drivers
* QED
* VDI
* VHDX
* VMDK
* Parallels
which have this callback. The presense of the callback means that
consistency check is supported.
The patch updates documentation accordingly.
Signed-off-by: Denis V. Lunev <den@openvz.org>
CC: Kevin Wolf <kwolf@redhat.com>
CC: Hanna Reitz <hreitz@redhat.com>
Message-Id: <20220407083932.531965-1-den@openvz.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
virtiofsd has introduced killpriv_v2/no_killpriv_v2 for a while. Add
description of it to docs/helper.
Signed-off-by: Liu Yiding <liuyd.fnst@fujitsu.com>
Message-Id: <20220421095151.2231099-1-liuyd.fnst@fujitsu.com>
[Small documentation fixes: s/as client supports/as the client supports/
and s/. /. /.
--Stefan]
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
When using the --list option, qemu-nbd acts as an NBD client rather
than a server. As such when using TLS, it has a need to validate
the server certificate. This adds a --tls-hostname option which can
be used to override the default hostname used for certificate
validation.
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20220304193610.3293146-5-berrange@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
To implement this, we reuse the existing daemonizing functions from the
system emulator, which mainly do the following:
- Fork off a child process, and set up a pipe between parent and child
- The parent process waits until the child sends a status byte over the
pipe (0 means that the child was set up successfully; anything else
(including errors or EOF) means that the child was not set up
successfully), and then exits with an appropriate exit status
- The child process enters a new session (forking off again), changes
the umask, and will ignore terminal signals from then on
- Once set-up is complete, the child will chdir to /, redirect all
standard I/O streams to /dev/null, and tell the parent that set-up has
been completed successfully
In contrast to qemu-nbd's --fork implementation, during the set up
phase, error messages are not piped through the parent process.
qemu-nbd mainly does this to detect errors, though (while os_daemonize()
has the child explicitly signal success after set up); because we do not
redirect stderr after forking, error messages continue to appear on
whatever the parent's stderr was (until set up is complete).
Signed-off-by: Hanna Reitz <hreitz@redhat.com>
Message-Id: <20220303164814.284974-4-hreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Provide an option "-o security_label/no_security_label" to enable/disable
security label functionality. By default these are turned off.
If enabled, server will indicate to client that it is capable of handling
one security label during file creation. Typically this is expected to
be a SELinux label. File server will set this label on the file. It will
try to set it atomically wherever possible. But its not possible in
all the cases.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Message-Id: <20220208204813.682906-11-vgoyal@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
qemu-img convert documents the backing file and backing format options
as follows:
[-B backing_file [-F backing_fmt]]
whereas qemu-img create has this:
[-b backing_file] [-F backing_fmt]
That is, for convert, we document that -F cannot be given without -B,
while for create, way say that they are independent.
Indeed, it is technically possible to give -F without -b, because it is
left to the block driver to decide whether this is an error or not, so
sometimes it is:
$ qemu-img create -f qed -F qed test.qed 64M
Formatting 'test.qed', fmt=qed size=67108864 backing_fmt=qed [...]
And sometimes it is not:
$ qemu-img create -f qcow2 -F qcow2 test.qcow2 64M
Formatting 'test.qcow2', fmt=qcow2 cluster_size=65536 [...]
qemu-img: test.qcow2: Backing format cannot be used without backing file
Generally, it does not make much sense, though, and users should only
give -F with -b, so document it that way, as we have already done for
qemu-img convert (commit 1899bf4737).
Reported-by: Tingting Mao <timao@redhat.com>
Signed-off-by: Hanna Reitz <hreitz@redhat.com>
Message-Id: <20220131135908.32393-1-hreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Andrey DrobyshevandKevin Wolf
Stefan Hajnoczi
Denis V. LunevandEric Blake
Christian Schoenebeck
Dr. David Alan Gilbert
Alex Bennée
Stefan WeilandLaurent Vivier
Markus ArmbrusterandKevin Wolf
Daniel P. BerrangéandThomas Huth
Xie YongjiandKevin Wolf
Liu YidingandStefan Hajnoczi
Hanna ReitzandKevin Wolf
Vivek GoyalandDr. David Alan Gilbert