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2023-05-19block: Call .bdrv_co_create(_opts) unlockedKevin Wolf
These are functions that modify the graph, so they must be able to take a writer lock. This is impossible if they already hold the reader lock. If they need a reader lock for some of their operations, they should take it internally. Many of them go through blk_*(), which will always take the lock itself. Direct calls of bdrv_*() need to take the reader lock. Note that while locking for bdrv_co_*() calls is checked by TSA, this is not the case for the mixed_coroutine_fns bdrv_*(). Holding the lock is still required when they are called from coroutine context like here! This effectively reverts 4ec8df0183, but adds some internal locking instead. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20230510203601.418015-2-kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-02-23block: Mark bdrv_co_create() and callers GRAPH_RDLOCKKevin Wolf
This adds GRAPH_RDLOCK annotations to declare that callers of bdrv_co_create() need to hold a reader lock for the graph. Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20230203152202.49054-17-kwolf@redhat.com> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2022-03-04block_int-common.h: assertions in the callers of BlockDriver function pointersEmanuele Giuseppe Esposito
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Message-Id: <20220303151616.325444-27-eesposit@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2019-09-13block/create: Do not abort if a block driver is not availablePhilippe Mathieu-Daudé
The 'blockdev-create' QMP command was introduced as experimental feature in commit b0292b851b8, using the assert() debug call. It got promoted to 'stable' command in 3fb588a0f2c, but the assert call was not removed. Some block drivers are optional, and bdrv_find_format() might return a NULL value, triggering the assertion. Stable code is not expected to abort, so return an error instead. This is easily reproducible when libnfs is not installed: ./configure [...] module support no Block whitelist (rw) Block whitelist (ro) libiscsi support yes libnfs support no [...] Start QEMU: $ qemu-system-x86_64 -S -qmp unix:/tmp/qemu.qmp,server,nowait Send the 'blockdev-create' with the 'nfs' driver: $ ( cat << 'EOF' {'execute': 'qmp_capabilities'} {'execute': 'blockdev-create', 'arguments': {'job-id': 'x', 'options': {'size': 0, 'driver': 'nfs', 'location': {'path': '/', 'server': {'host': '::1', 'type': 'inet'}}}}, 'id': 'x'} EOF ) | socat STDIO UNIX:/tmp/qemu.qmp {"QMP": {"version": {"qemu": {"micro": 50, "minor": 1, "major": 4}, "package": "v4.1.0-733-g89ea03a7dc"}, "capabilities": ["oob"]}} {"return": {}} QEMU crashes: $ gdb qemu-system-x86_64 core Program received signal SIGSEGV, Segmentation fault. (gdb) bt #0 0x00007ffff510957f in raise () at /lib64/libc.so.6 #1 0x00007ffff50f3895 in abort () at /lib64/libc.so.6 #2 0x00007ffff50f3769 in _nl_load_domain.cold.0 () at /lib64/libc.so.6 #3 0x00007ffff5101a26 in .annobin_assert.c_end () at /lib64/libc.so.6 #4 0x0000555555d7e1f1 in qmp_blockdev_create (job_id=0x555556baee40 "x", options=0x555557666610, errp=0x7fffffffc770) at block/create.c:69 #5 0x0000555555c96b52 in qmp_marshal_blockdev_create (args=0x7fffdc003830, ret=0x7fffffffc7f8, errp=0x7fffffffc7f0) at qapi/qapi-commands-block-core.c:1314 #6 0x0000555555deb0a0 in do_qmp_dispatch (cmds=0x55555645de70 <qmp_commands>, request=0x7fffdc005c70, allow_oob=false, errp=0x7fffffffc898) at qapi/qmp-dispatch.c:131 #7 0x0000555555deb2a1 in qmp_dispatch (cmds=0x55555645de70 <qmp_commands>, request=0x7fffdc005c70, allow_oob=false) at qapi/qmp-dispatch.c:174 With this patch applied, QEMU returns a QMP error: {'execute': 'blockdev-create', 'arguments': {'job-id': 'x', 'options': {'size': 0, 'driver': 'nfs', 'location': {'path': '/', 'server': {'host': '::1', 'type': 'inet'}}}}, 'id': 'x'} {"id": "x", "error": {"class": "GenericError", "desc": "Block driver 'nfs' not found or not supported"}} Cc: qemu-stable@nongnu.org Reported-by: Xu Tian <xutian@redhat.com> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: John Snow <jsnow@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2019-08-16Include qemu/main-loop.h lessMarkus Armbruster
In my "build everything" tree, changing qemu/main-loop.h triggers a recompile of some 5600 out of 6600 objects (not counting tests and objects that don't depend on qemu/osdep.h). It includes block/aio.h, which in turn includes qemu/event_notifier.h, qemu/notify.h, qemu/processor.h, qemu/qsp.h, qemu/queue.h, qemu/thread-posix.h, qemu/thread.h, qemu/timer.h, and a few more. Include qemu/main-loop.h only where it's needed. Touching it now recompiles only some 1700 objects. For block/aio.h and qemu/event_notifier.h, these numbers drop from 5600 to 2800. For the others, they shrink only slightly. Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20190812052359.30071-21-armbru@redhat.com> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
2018-08-31jobs: utilize job_exit shimJohn Snow
Utilize the job_exit shim by not calling job_defer_to_main_loop, and where applicable, converting the deferred callback into the job_exit callback. This converts backup, stream, create, and the unit tests all at once. Most of these jobs do not see any changes to the order in which they clean up their resources, except the test-blockjob-txn test, which now puts down its bs before job_completed is called. This is safe for the same reason the reordering in the mirror job is safe, because job_completed no longer runs under two locks, making the unref safe even if it causes a flush. Signed-off-by: John Snow <jsnow@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 20180830015734.19765-7-jsnow@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
2018-08-31jobs: canonize Error objectJohn Snow
Jobs presently use both an Error object in the case of the create job, and char strings in the case of generic errors elsewhere. Unify the two paths as just j->err, and remove the extra argument from job_completed. The integer error code for job_completed is kept for now, to be removed shortly in a separate patch. Signed-off-by: John Snow <jsnow@redhat.com> Message-id: 20180830015734.19765-3-jsnow@redhat.com [mreitz: Dropped a superfluous g_strdup()] Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2018-08-31jobs: change start callback to run callbackJohn Snow
Presently we codify the entry point for a job as the "start" callback, but a more apt name would be "run" to clarify the idea that when this function returns we consider the job to have "finished," except for any cleanup which occurs in separate callbacks later. As part of this clarification, change the signature to include an error object and a return code. The error ptr is not yet used, and the return code while captured, will be overwritten by actions in the job_completed function. Signed-off-by: John Snow <jsnow@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 20180830015734.19765-2-jsnow@redhat.com Reviewed-by: Jeff Cody <jcody@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
2018-05-30block/create: Mark blockdev-create stableKevin Wolf
We're ready to declare the blockdev-create job stable. This renames the corresponding QMP command from x-blockdev-create to blockdev-create. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Jeff Cody <jcody@redhat.com>
2018-05-30block/create: Make x-blockdev-create a jobKevin Wolf
This changes the x-blockdev-create QMP command so that it doesn't block the monitor and the main loop any more, but starts a background job that performs the image creation. The basic job as implemented here is all that is necessary to make image creation asynchronous and to provide a QMP interface that can be marked stable, but it still lacks a few features that jobs usually provide: The job will ignore pause commands and it doesn't publish more than very basic progress yet (total-progress is 1 and current-progress advances from 0 to 1 when the driver callbacks returns). These features can be added later without breaking compatibility. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Jeff Cody <jcody@redhat.com>
2018-03-09block: x-blockdev-create QMP commandKevin Wolf
This adds a synchronous x-blockdev-create QMP command that can create qcow2 images on a given node name. We don't want to block while creating an image, so this is not the final interface in all aspects, but BlockdevCreateOptionsQcow2 and .bdrv_co_create() are what they actually might look like in the end. In any case, this should be good enough to test whether we interpret BlockdevCreateOptions as we should. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>