Rename
nbd_wr_syncv -> nbd_rwv
read_sync -> nbd_read
read_sync_eof -> nbd_read_eof
write_sync -> nbd_write
drop_sync -> nbd_drop
1. nbd_ prefix
read_sync and write_sync are already shared, so it is good to have a
namespace prefix. drop_sync will be shared, and read_sync_eof is
related to read_sync, so let's rename them all.
2. _sync suffix
_sync is related to the fact that nbd_wr_syncv doesn't return if a
write to socket returns EAGAIN. The first implementation of
nbd_wr_syncv (was wr_sync in 7a5ca8648b) just loops while getting
EAGAIN, the current implementation yields in this case.
Why we want to get rid of it:
- it is normal for r/w functions to be synchronous, so having an
additional suffix for it looks redundant (contrariwise, we have
_aio suffix for async functions)
- _sync suffix in block layer is used when function does flush (so
using it for other thing is confusing a bit)
- keep function names short after adding nbd_ prefix
3. for nbd_wr_syncv let's use more common notation 'rw'
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20170602150150.258222-2-vsementsov@virtuozzo.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Back in qemu 2.5, qemu-nbd was immune to port probes (a transient
server would not quit, regardless of how many probe connections
came and went, until a connection actually negotiated). But we
broke that in commit ee7d7aa when removing the return value to
nbd_client_new(), although that patch also introduced a bug causing
an assertion failure on a client that fails negotiation. We then
made it worse during refactoring in commit 1a6245a (a segfault
before we could even assert); the (masked) assertion was cleaned
up in d3780c2 (still in 2.6), and just recently we finally fixed
the segfault ("nbd: Fully intialize client in case of failed
negotiation"). But that still means that ever since we added
TLS support to qemu-nbd, we have been vulnerable to an ill-timed
port-scan being able to cause a denial of service by taking down
qemu-nbd before a real client has a chance to connect.
Since negotiation is now handled asynchronously via coroutines,
we no longer have a synchronous point of return by re-adding a
return value to nbd_client_new(). So this patch instead wires
things up to pass the negotiation status through the close_fn
callback function.
Simple test across two terminals:
$ qemu-nbd -f raw -p 30001 file
$ nmap 127.0.0.1 -p 30001 && \
qemu-io -c 'r 0 512' -f raw nbd://localhost:30001
Note that this patch does not change what constitutes successful
negotiation (thus, a client must enter transmission phase before
that client can be considered as a reason to terminate the server
when the connection ends). Perhaps we may want to tweak things
in a later patch to also treat a client that uses NBD_OPT_ABORT
as being a 'successful' negotiation (the client correctly talked
the NBD protocol, and informed us it was not going to use our
export after all), but that's a discussion for another day.
Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1451614
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20170608222617.20376-1-eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Move to modern errp scheme from just LOGging errors.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20170526110913.89098-1-vsementsov@virtuozzo.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Will be used in following patch to provide actual error message in
some cases.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20170516094533.6160-4-vsementsov@virtuozzo.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Start removing migration code from sysemu/sysemu.h.
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
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Merge remote-tracking branch 'kwolf/tags/for-upstream' into staging
Block layer patches
# gpg: Signature made Mon 29 May 2017 03:34:59 PM BST
# gpg: using RSA key 0x7F09B272C88F2FD6
# gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>"
# Primary key fingerprint: DC3D EB15 9A9A F95D 3D74 56FE 7F09 B272 C88F 2FD6
* kwolf/tags/for-upstream:
block/file-*: *_parse_filename() and colons
block: Fix backing paths for filenames with colons
block: Tweak error message related to qemu-img amend
qemu-img: Fix leakage of options on error
qemu-img: copy *key-secret opts when opening newly created files
qemu-img: introduce --target-image-opts for 'convert' command
qemu-img: fix --image-opts usage with dd command
qemu-img: add support for --object with 'dd' command
qemu-img: Fix documentation of convert
qcow2: remove extra local_error variable
mirror: Drop permissions on s->target on completion
nvme: Add support for Controller Memory Buffers
iotests: 147: Don't test inet6 if not available
qemu-iotests: Test streaming with missing job ID
stream: fix crash in stream_start() when block_job_create() fails
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
The file drivers' *_parse_filename() implementations just strip the
optional protocol prefix off the filename. However, for e.g.
"file:foo:bar", this would lead to "foo:bar" being stored as the BDS's
filename which looks like it should be managed using the "foo" protocol.
This is especially troublesome if you then try to resolve a backing
filename based on "foo:bar".
This issue can only occur if the stripped part is a relative filename
("file:/foo:bar" will be shortened to "/foo:bar" and having a slash
before the first colon means that "/foo" is not recognized as a protocol
part). Therefore, we can easily fix it by prepending "./" to such
filenames.
Before this patch:
$ ./qemu-img create -f qcow2 backing.qcow2 64M
Formatting 'backing.qcow2', fmt=qcow2 size=67108864 encryption=off
cluster_size=65536 lazy_refcounts=off refcount_bits=16
$ ./qemu-img create -f qcow2 -b backing.qcow2 file🔝image.qcow2
Formatting 'file🔝image.qcow2', fmt=qcow2 size=67108864
backing_file=backing.qcow2 encryption=off cluster_size=65536
lazy_refcounts=off refcount_bits=16
$ ./qemu-io file🔝image.qcow2
can't open device file🔝image.qcow2: Could not open backing file:
Unknown protocol 'top'
After this patch:
$ ./qemu-io file🔝image.qcow2
[no error]
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-id: 20170522195217.12991-3-mreitz@redhat.com
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
All block jobs are using block_job_defer_to_main_loop as the final
step just before the coroutine terminates. At this point,
block_job_enter should do nothing, but currently it restarts
the freed coroutine.
Now, the job->co states should probably be changed to an enum
(e.g. BEFORE_START, STARTED, YIELDED, COMPLETED) subsuming
block_job_started, job->deferred_to_main_loop and job->busy.
For now, this patch eliminates the problematic reenter by
removing the reset of job->deferred_to_main_loop (which served
no purpose, as far as I could see) and checking the flag in
block_job_enter.
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 20170508141310.8674-12-pbonzini@redhat.com
Signed-off-by: Jeff Cody <jcody@redhat.com>
Remove use of block_job_pause/resume from outside blockjob.c, thus
making them static. The new functions are used by the block layer,
so place them in blockjob_int.h.
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Message-id: 20170508141310.8674-5-pbonzini@redhat.com
Signed-off-by: Jeff Cody <jcody@redhat.com>
Outside blockjob.c, block_job_unref is only used when a block job fails
to start, and block_job_ref is not used at all. The reference counting
thus is pretty well hidden. Introduce a separate function to be used
by block jobs; because block_job_ref and block_job_unref now become
static, move them earlier in blockjob.c.
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Message-id: 20170508141310.8674-4-pbonzini@redhat.com
Signed-off-by: Jeff Cody <jcody@redhat.com>
This is unused since commit 66a0fae ("blockjob: Don't touch BDS iostatus",
2016-05-19).
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Message-id: 20170508141310.8674-3-pbonzini@redhat.com
Signed-off-by: Jeff Cody <jcody@redhat.com>
The main loop uses aio_disable_external()/aio_enable_external() to
temporarily disable processing of external AioContext clients like
device emulation.
This allows monitor commands to quiesce I/O and prevent the guest from
submitting new requests while a monitor command is in progress.
The aio_enable_external() API is currently broken when an IOThread is in
aio_poll() waiting for fd activity when the main loop re-enables
external clients. Incrementing ctx->external_disable_cnt does not wake
the IOThread from ppoll(2) so fd processing remains suspended and leads
to unresponsive emulated devices.
This patch adds an aio_notify() call to aio_enable_external() so the
IOThread is kicked out of ppoll(2) and will re-arm the file descriptors.
The bug can be reproduced as follows:
$ qemu -M accel=kvm -m 1024 \
-object iothread,id=iothread0 \
-device virtio-scsi-pci,iothread=iothread0,id=virtio-scsi-pci0 \
-drive if=none,id=drive0,aio=native,cache=none,format=raw,file=test.img \
-device scsi-hd,id=scsi-hd0,drive=drive0 \
-qmp tcp::5555,server,nowait
$ scripts/qmp/qmp-shell localhost:5555
(qemu) blockdev-snapshot-sync device=drive0 snapshot-file=sn1.qcow2
mode=absolute-paths format=qcow2
After blockdev-snapshot-sync completes the SCSI disk will be
unresponsive. This leads to request timeouts inside the guest.
Reported-by: Qianqian Zhu <qizhu@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20170508180705.20609-1-stefanha@redhat.com
Suggested-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
We had some conflicting documentation: a nice 8-way table that
described all possible combinations of DATA, ZERO, and
OFFSET_VALID, contrasted with text that implied that OFFSET_VALID
always meant raw data could be read directly. Furthermore, the
text refers a lot to bs->file, even though the interface was
updated back in 67a0fd2a to let the driver pass back a specific
BDS (not necessarily bs->file). As the 8-way table is the
intended semantics, simplify the rest of the text to get rid of
the confusion.
ALLOCATED is always set by the block layer for convenience (drivers
do not have to worry about it). RAW is used only internally, but
by more than the raw driver. Document these additional items on
the driver callback.
Suggested-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 20170507000552.20847-4-eblake@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
Format drivers for inactive nodes don't need write/resize permissions on
their bs->file and can share write/resize with another VM (in fact, this
is the whole point of keeping images inactive). Represent this fact in
the op blocker system, so that image locking does the right thing
without special-casing inactive images.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
With image locking, permissions affect other qemu processes as well. We
want to be sure that the destination can run, so let's drop permissions
on the source when migration completes.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Instead of manually calling blk_resume_after_migration() in migration
code after doing bdrv_invalidate_cache_all(), integrate the BlockBackend
activation with cache invalidation into a single function. This is
achieved with a new callback in BdrvChildRole that is called by
bdrv_invalidate_cache_all().
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
It can be used outside of block.c for making user friendly messages.
Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
SocketAddressLegacy is a simple union, and simple unions are awkward:
they have their variant members wrapped in a "data" object on the
wire, and require additional indirections in C. SocketAddress is the
equivalent flat union. Convert all users of SocketAddressLegacy to
SocketAddress, except for existing external interfaces.
See also commit fce5d53..9445673 and 85a82e8..c5f1ae3.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <1493192202-3184-7-git-send-email-armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
[Minor editing accident fixed, commit message and a comment tweaked]
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Klim Kireev <proffk@virtuozzo.mipt.ru>
Signed-off-by: Denis V. Lunev <den@openvz.org>
CC: Kevin Wolf <kwolf@redhat.com>
CC: Max Reitz <mreitz@redhat.com>
Message-id: 1491405505-31620-2-git-send-email-den@openvz.org
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Add an Error parameter to the block drivers' bdrv_truncate() interface.
If a block driver does not set this in case of an error, the generic
bdrv_truncate() implementation will do so.
Where it is obvious, this patch also makes some block drivers set this
value.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-id: 20170328205129.15138-4-mreitz@redhat.com
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
For one thing, this allows us to drop the error message generation from
qemu-img.c and blockdev.c and instead have it unified in
bdrv_truncate().
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-id: 20170328205129.15138-3-mreitz@redhat.com
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Introduce check function for setting read_only flags. Will return < 0 on
error, with appropriate Error value set. Does not alter any flags.
Signed-off-by: Jeff Cody <jcody@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Message-id: e2bba34ac3bc76a0c42adc390413f358ae0566e8.1491597120.git.jcody@redhat.com
A few block drivers will set the BDS read_only flag from their
.bdrv_open() function. This means the bs->read_only flag could
be set after we enable copy_on_read, as the BDRV_O_COPY_ON_READ
flag check occurs prior to the call to bdrv->bdrv_open().
This adds an error return to bdrv_set_read_only(), and an error will be
return if we try to set the BDS to read_only while copy_on_read is
enabled.
This patch also changes the behavior of vvfat. Before, vvfat could
override the drive 'readonly' flag with its own, internal 'rw' flag.
For instance, this -drive parameter would result in a writable image:
"-drive format=vvfat,dir=/tmp/vvfat,rw,if=virtio,readonly=on"
This is not correct. Now, attempting to use the above -drive parameter
will result in an error (i.e., 'rw' is incompatible with 'readonly=on').
Signed-off-by: Jeff Cody <jcody@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Message-id: 0c5b4c1cc2c651471b131f21376dfd5ea24d2196.1491597120.git.jcody@redhat.com
We have a helper wrapper for checking for the BDS read_only flag,
add a helper wrapper to set the read_only flag as well.
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Jeff Cody <jcody@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Message-id: 9b18972d05f5fa2ac16c014f0af98d680553048d.1491597120.git.jcody@redhat.com
During block job completion, nothing is preventing
block_job_defer_to_main_loop_bh from being called in a nested
aio_poll(), which is a trouble, such as in this code path:
qmp_block_commit
commit_active_start
bdrv_reopen
bdrv_reopen_multiple
bdrv_reopen_prepare
bdrv_flush
aio_poll
aio_bh_poll
aio_bh_call
block_job_defer_to_main_loop_bh
stream_complete
bdrv_reopen
block_job_defer_to_main_loop_bh is the last step of the stream job,
which should have been "paused" by the bdrv_drained_begin/end in
bdrv_reopen_multiple, but it is not done because it's in the form of a
main loop BH.
Similar to why block jobs should be paused between drained_begin and
drained_end, BHs they schedule must be excluded as well. To achieve
this, this patch forces draining the BH in BDRV_POLL_WHILE.
As a side effect this fixes a hang in block_job_detach_aio_context
during system_reset when a block job is ready:
#0 0x0000555555aa79f3 in bdrv_drain_recurse
#1 0x0000555555aa825d in bdrv_drained_begin
#2 0x0000555555aa8449 in bdrv_drain
#3 0x0000555555a9c356 in blk_drain
#4 0x0000555555aa3cfd in mirror_drain
#5 0x0000555555a66e11 in block_job_detach_aio_context
#6 0x0000555555a62f4d in bdrv_detach_aio_context
#7 0x0000555555a63116 in bdrv_set_aio_context
#8 0x0000555555a9d326 in blk_set_aio_context
#9 0x00005555557e38da in virtio_blk_data_plane_stop
#10 0x00005555559f9d5f in virtio_bus_stop_ioeventfd
#11 0x00005555559fa49b in virtio_bus_stop_ioeventfd
#12 0x00005555559f6a18 in virtio_pci_stop_ioeventfd
#13 0x00005555559f6a18 in virtio_pci_reset
#14 0x00005555559139a9 in qdev_reset_one
#15 0x0000555555916738 in qbus_walk_children
#16 0x0000555555913318 in qdev_walk_children
#17 0x0000555555916738 in qbus_walk_children
#18 0x00005555559168ca in qemu_devices_reset
#19 0x000055555581fcbb in pc_machine_reset
#20 0x00005555558a4d96 in qemu_system_reset
#21 0x000055555577157a in main_loop_should_exit
#22 0x000055555577157a in main_loop
#23 0x000055555577157a in main
The rationale is that the loop in block_job_detach_aio_context cannot
make any progress in pausing/completing the job, because bs->in_flight
is 0, so bdrv_drain doesn't process the block_job_defer_to_main_loop
BH. With this patch, it does.
Reported-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
Message-Id: <20170418143044.12187-3-famz@redhat.com>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Tested-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
They start the coroutine on the specified context.
Signed-off-by: Fam Zheng <famz@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Usually guest devices don't like other writers to the same image, so
they use blk_set_perm() to prevent this from happening. In the migration
phase before the VM is actually running, though, they don't have a
problem with writes to the image. On the other hand, storage migration
needs to be able to write to the image in this phase, so the restrictive
blk_set_perm() call of qdev devices breaks it.
This patch flags all BlockBackends with a qdev device as
blk->disable_perm during incoming migration, which means that the
requested permissions are stored in the BlockBackend, but not actually
applied to its root node yet.
Once migration has finished and the VM should be resumed, the
permissions are applied. If they cannot be applied (e.g. because the NBD
server used for block migration hasn't been shut down), resuming the VM
fails.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Tested-by: Kashyap Chamarthy <kchamart@redhat.com>
bdrv_child_set_perm alone is not very usable because the caller must
call bdrv_child_check_perm first. This is already encapsulated
conveniently in bdrv_child_try_set_perm, so remove the other prototypes
from the header and fix the one wrong caller, block/mirror.c.
Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
When adding an Error parameter, bdrv_replace_in_backing_chain() would
become nothing more than a wrapper around change_parent_backing_link().
So make the latter public, renamed as bdrv_replace_node(), and remove
bdrv_replace_in_backing_chain().
Most of the callers just remove a node from the graph that they just
inserted, so they can use &error_abort, but completion of a mirror job
with 'replaces' set can actually fail.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
change_parent_backing_link() will need to update multiple BdrvChild
objects at once. Checking permissions reference by reference doesn't
work because permissions need to be consistent only with all parents
moved to the new child.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Aborting on error in bdrv_append() isn't correct. This patch fixes it
and lets the callers handle failures.
Test case 085 needs a reference output update. This is caused by the
reversed order of bdrv_set_backing_hd() and change_parent_backing_link()
in bdrv_append(): When the backing file of the new node is set, the
parent nodes are still pointing to the old top, so the backing blocker
is now initialised with the node name rather than the BlockBackend name.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Acked-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Not all callers of bdrv_set_backing_hd() know for sure that attaching
the backing file will be allowed by the permission system. Return the
error from the function rather than aborting.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Acked-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Management tools need to be able to know about every node in the graph
and need a way to address them. Changing the graph structure was okay
because libvirt doesn't really manage the node level yet, but future
libvirt versions need to deal with both new and old version of qemu.
This new option to blockdev-commit allows the client to set a node-name
for the automatically inserted filter driver, and at the same time
serves as a witness for a future libvirt that this version of qemu does
automatically insert a filter driver.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Acked-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Management tools need to be able to know about every node in the graph
and need a way to address them. Changing the graph structure was okay
because libvirt doesn't really manage the node level yet, but future
libvirt versions need to deal with both new and old version of qemu.
This new option to blockdev-mirror allows the client to set a node-name
for the automatically inserted filter driver, and at the same time
serves as a witness for a future libvirt that this version of qemu does
automatically insert a filter driver.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Acked-by: Fam Zheng <famz@redhat.com>
In some cases, we want to remove op blockers on intermediate nodes
before the whole block job transaction has completed (because they block
restoring the final graph state during completion). Provide a function
for this.
The whole block job lifecycle is a bit messed up and it's hard to
actually do all things in the right order, but I'll leave simplifying
this for another day.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Acked-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Backing files are somewhat special compared to other kinds of children
because they are attached and detached using bdrv_set_backing_hd()
rather than the normal set of functions, which does a few more things
like setting backing blockers, toggling the BDRV_O_NO_BACKING flag,
setting parent_bs->backing_file, etc.
These special features are a reason why change_parent_backing_link()
can't handle backing files yet. With abstracting the additional features
into .attach/.detach callbacks, we get a step closer to a function that
can actually deal with this.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Acked-by: Fam Zheng <famz@redhat.com>
Block jobs don't actually do I/O through the the reference they create
with block_job_add_bdrv(), but they might want to use the permisssion
system to express what the block job does to intermediate nodes. This
adds permissions to block_job_add_bdrv() to provide the means to request
permissions.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Acked-by: Fam Zheng <famz@redhat.com>
When the parents' child links are updated in bdrv_append() or
bdrv_replace_in_backing_chain(), this should affect all child links of
BlockBackends or other nodes, but not on child links held for other
purposes (like for setting permissions). This patch allows to control
the behaviour per BdrvChildRole.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Acked-by: Fam Zheng <famz@redhat.com>
For meaningful error messages in the permission system, we need to get
some human-readable description of the parent of a BdrvChild.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Acked-by: Fam Zheng <famz@redhat.com>
This functions creates a BlockBackend internally, so the block jobs need
to tell it what they want to do with the BB.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Acked-by: Fam Zheng <famz@redhat.com>
Some devices allow a media change between read-only and read-write
media. They need to adapt the permissions in their .change_media_cb()
implementation, which can fail. So add an Error parameter to the
function.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Acked-by: Fam Zheng <famz@redhat.com>
blk_new_open() is a convenience function that processes flags rather
than QDict options as a simple way to just open an image file.
In order to keep it convenient in the future, it must automatically
request the necessary permissions. This can easily be inferred from the
flags for read and write, but we need another flag that tells us whether
to get the resize permission.
We can't just always request it because that means that no block jobs
can run on the resulting BlockBackend (which is something that e.g.
qemu-img commit wants to do), but we also can't request it never because
most of the .bdrv_create() implementations call blk_truncate().
The solution is to introduce another flag that is passed by all users
that want to resize the image.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Acked-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
vvfat is the last remaining driver that can have children, but doesn't
implement .bdrv_child_perm() yet. The default handlers aren't suitable
here, so let's implement a very simple driver-specific one that protects
the internal child from being used by other users as good as our
permissions permit.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Acked-by: Fam Zheng <famz@redhat.com>
Almost all format drivers have the same characteristics as far as
permissions are concerned: They have one or more children for storing
their own data and, more importantly, metadata (can be written to and
grow even without external write requests, must be protected against
other writers and present consistent data) and optionally a backing file
(this is just data, so like for a filter, it only depends on what the
parent nodes need).
This provides a default implementation that can be shared by most of
our format drivers.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Acked-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
