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Markus Armbruster 26f54e9a3c block: New BlockBackend
A block device consists of a frontend device model and a backend.

A block backend has a tree of block drivers doing the actual work.
The tree is managed by the block layer.

We currently use a single abstraction BlockDriverState both for tree
nodes and the backend as a whole.  Drawbacks:

* Its API includes both stuff that makes sense only at the block
  backend level (root of the tree) and stuff that's only for use
  within the block layer.  This makes the API bigger and more complex
  than necessary.  Moreover, it's not obvious which interfaces are
  meant for device models, and which really aren't.

* Since device models keep a reference to their backend, the backend
  object can't just be destroyed.  But for media change, we need to
  replace the tree.  Our solution is to make the BlockDriverState
  generic, with actual driver state in a separate object, pointed to
  by member opaque.  That lets us replace the tree by deinitializing
  and reinitializing its root.  This special need of the root makes
  the data structure awkward everywhere in the tree.

The general plan is to separate the APIs into "block backend", for use
by device models, monitor and whatever other code dealing with block
backends, and "block driver", for use by the block layer and whatever
other code (if any) dealing with trees and tree nodes.

Code dealing with block backends, device models in particular, should
become completely oblivious of BlockDriverState.  This should let us
clean up both APIs, and the tree data structures.

This commit is a first step.  It creates a minimal "block backend"
API: type BlockBackend and functions to create, destroy and find them.

BlockBackend objects are created and destroyed exactly when root
BlockDriverState objects are created and destroyed.  "Root" in the
sense of "in bdrv_states".  They're not yet used for anything; that'll
come shortly.

A root BlockDriverState is created with bdrv_new_root(), so where to
create a BlockBackend is obvious.  Where these roots get destroyed
isn't always as obvious.

It is obvious in qemu-img.c, qemu-io.c and qemu-nbd.c, and in error
paths of blockdev_init(), blk_connect().  That leaves destruction of
objects successfully created by blockdev_init() and blk_connect().

blockdev_init() is used only by drive_new() and qmp_blockdev_add().
Objects created by the latter are currently indestructible (see commit
48f364d "blockdev: Refuse to drive_del something added with
blockdev-add" and commit 2d246f0 "blockdev: Introduce
DriveInfo.enable_auto_del").  Objects created by the former get
destroyed by drive_del().

Objects created by blk_connect() get destroyed by blk_disconnect().

BlockBackend is reference-counted.  Its reference count never exceeds
one so far, but that's going to change.

In drive_del(), the BB's reference count is surely one now.  The BDS's
reference count is greater than one when something else is holding a
reference, such as a block job.  In this case, the BB is destroyed
right away, but the BDS lives on until all extra references get
dropped.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-10-20 13:41:26 +02:00
audio audio: Drop superfluous conditionals around g_free() 2014-06-13 12:34:54 +02:00
backends pci, pc, virtio, misc bugfixes 2014-09-18 20:02:01 +01:00
block block: New BlockBackend 2014-10-20 13:41:26 +02:00
bsd-user bsd-user: Fix syscall format, add strace support for more syscalls 2014-06-11 00:25:06 +01:00
default-configs PPC: Fix default config ordering and add eTSEC for ppc64 2014-09-08 12:50:54 +02:00
disas tcg-sparc: Use UMULXHI instruction 2014-09-29 14:55:27 -04:00
docs vga-pci: add qext region to mmio 2014-10-15 11:08:35 +02:00
dtc@bc895d6d09
fpu fpu: softfloat: drop INLINE macro 2014-06-23 11:00:12 -04:00
fsdev virtfs-proxy-helper: fix call to accept 2014-04-28 08:55:32 +04:00
gdb-xml s390x/gdb: add the feature xml files for s390x 2014-09-01 09:45:19 +02:00
hw block: New BlockBackend 2014-10-20 13:41:26 +02:00
include block: New BlockBackend 2014-10-20 13:41:26 +02:00
libcacard Fix typos and misspellings in comments 2014-09-20 17:55:53 +04:00
libdecnumber libdecnumber: Fix warnings from smatch (missing static, boolean operations) 2014-08-24 13:21:06 +04:00
linux-headers linux-headers: update to 3.17-rc7 2014-10-10 10:37:47 +02:00
linux-user translate-all.c: memory walker initial address miscalculation 2014-10-06 21:53:35 +03:00
net Net patches 2014-09-04 17:39:07 +01:00
pc-bios linuxboot: compute initrd loading address 2014-10-09 15:36:15 +02:00
pixman@87eea99e44 pixman: update internal copy to pixman-0.32.6 2014-09-15 08:14:19 +02:00
po po: fix conflict with %.mo rule in rules.mak 2014-09-26 13:35:08 +02:00
qapi qapi: Add corrupt field to ImageInfoSpecificQCow2 2014-10-04 19:18:17 +01:00
qga channel-posix: using qemu_set_nonblock() instead of fcntl(O_NONBLOCK) 2014-08-15 18:03:13 +01:00
qobject json-lexer: fix escaped backslash in single-quoted string 2014-06-23 11:01:24 -04:00
qom qom: Add description field in ObjectProperty struct 2014-10-15 05:03:15 +02:00
roms Update OpenBIOS images 2014-09-25 13:34:03 +01:00
scripts Merge remote-tracking branch 'remotes/qmp-unstable/queue/qmp' into staging 2014-09-29 18:18:29 +01:00
slirp slirp: udp: fix NULL pointer dereference because of uninitialized socket 2014-09-23 19:15:05 +01:00
stubs block: Keep DriveInfo alive until BlockDriverState dies 2014-09-25 15:24:14 +02:00
sysconfigs/target
target-alpha target-alpha: Use cpu_exec_interrupt qom hook 2014-09-25 18:54:21 +01:00
target-arm gdbstub: Allow target CPUs to specify watchpoint STOP_BEFORE_ACCESS flag 2014-10-06 14:25:43 +01:00
target-cris gdbstub: Allow target CPUs to specify watchpoint STOP_BEFORE_ACCESS flag 2014-10-06 14:25:43 +01:00
target-i386 Usual mix of patches, the most important being Alex and Marcelo's 2014-09-26 15:41:50 +01:00
target-lm32 gdbstub: Allow target CPUs to specify watchpoint STOP_BEFORE_ACCESS flag 2014-10-06 14:25:43 +01:00
target-m68k target-m68k: Use cpu_exec_interrupt qom hook 2014-09-25 18:54:21 +01:00
target-microblaze target-microblaze: Use cpu_exec_interrupt qom hook 2014-09-25 18:54:22 +01:00
target-mips gdbstub: Allow target CPUs to specify watchpoint STOP_BEFORE_ACCESS flag 2014-10-06 14:25:43 +01:00
target-moxie softmmu: introduce cpu_ldst.h 2014-06-05 16:10:33 +02:00
target-openrisc target-openrisc: Use cpu_exec_interrupt qom hook 2014-09-25 18:54:22 +01:00
target-ppc qdev: Drop legacy_name from qdev properties 2014-10-15 05:03:15 +02:00
target-s390x s390x/migration: migrate CPU state 2014-10-10 13:31:51 +02:00
target-sh4 target-sh4: Use cpu_exec_interrupt qom hook 2014-09-25 18:54:22 +01:00
target-sparc target-sparc: Use cpu_exec_interrupt qom hook 2014-09-25 18:54:22 +01:00
target-tricore target-tricore: Remove the dummy interrupt boilerplate 2014-09-25 18:54:22 +01:00
target-unicore32 target-unicore32: Use cpu_exec_interrupt qom hook 2014-09-25 18:54:22 +01:00
target-xtensa gdbstub: Allow target CPUs to specify watchpoint STOP_BEFORE_ACCESS flag 2014-10-06 14:25:43 +01:00
tcg tcg: Always enable TCGv type checking 2014-09-29 14:55:28 -04:00
tests glib: add compatibility interface for g_get_monotonic_time() 2014-10-15 13:43:35 +01:00
trace trace: [hmp] Reimplement "trace-event" and "info trace-events" using QMP 2014-09-26 09:34:38 +01:00
ui input monitor patches: fix send-key release ordering 2014-10-02 15:01:48 +01:00
util Four changes here. Polling for reconnection of character devices, 2014-10-09 15:09:05 +01:00
.exrc
.gitignore trace: [tcg] Generate TCG tracing routines 2014-08-12 14:26:12 +01:00
.gitmodules PPC: Add u-boot firmware for e500 2014-06-16 13:24:35 +02:00
.mailmap
.travis.yml .travis.yml: remove "make check" from main matrix 2014-09-26 21:05:06 +04:00
CODING_STYLE CODING_STYLE: Section about conditional statement 2014-08-15 18:54:06 +04:00
COPYING
COPYING.LIB
Changelog
HACKING
LICENSE
MAINTAINERS MAINTAINERS: update sheepdog maintainer 2014-09-08 11:12:43 +01:00
Makefile trace: install trace-events file 2014-09-26 09:34:39 +01:00
Makefile.objs qemu-file: Move stdio implementation to qemu-file-stdio.c 2014-10-14 10:29:28 +02:00
Makefile.target bootdevice: move bootdevice related code to new file bootdevice.c 2014-10-15 09:49:48 +02:00
README
VERSION Open 2.2 development tree 2014-08-01 18:30:08 +01:00
accel.c accel: Create accel object when initializing machine 2014-10-09 15:36:14 +02:00
aio-posix.c AioContext: introduce aio_prepare 2014-08-29 10:46:58 +01:00
aio-win32.c aio-win32: avoid out-of-bounds access to the events array 2014-09-22 11:39:21 +01:00
arch_init.c migration: catch unknown flag combinations in ram_load 2014-10-14 11:24:20 +02:00
async.c async: aio_context_new(): Handle event_notifier_init failure 2014-09-22 11:39:48 +01:00
balloon.c qapi event: convert BALLOON_CHANGE 2014-06-23 11:12:28 -04:00
block-migration.c block: Use g_new() & friends where that makes obvious sense 2014-08-20 11:51:28 +02:00
block.c block: Split bdrv_new_root() off bdrv_new() 2014-10-20 13:41:26 +02:00
blockdev-nbd.c block: Use g_new() & friends where that makes obvious sense 2014-08-20 11:51:28 +02:00
blockdev.c block: New BlockBackend 2014-10-20 13:41:26 +02:00
blockjob.c coroutine: Drop co_sleep_ns 2014-08-29 10:46:58 +01:00
bootdevice.c bootindex: change fprintf to error_report 2014-10-15 10:46:01 +02:00
bt-host.c
bt-vhci.c
configure configure: Build GDB XML for 32 bit ARM CPUs into qemu aarch64 binaries 2014-09-29 18:48:47 +01:00
coroutine-gthread.c glib-compat.h: add new thread API emulation on top of pre-2.31 API 2014-06-10 07:44:01 +02:00
coroutine-sigaltstack.c
coroutine-ucontext.c
coroutine-win32.c coroutine-win32.c: Add noinline attribute to work around gcc bug 2014-06-26 14:08:14 +01:00
cpu-exec.c cpu-exec: Do CPU_INTERRUPT_HALT unconditionally 2014-09-25 18:54:22 +01:00
cpus.c Introduce cpu_clean_all_dirty 2014-09-16 11:04:09 +02:00
cputlb.c implementing victim TLB for QEMU system emulated TLB 2014-09-01 17:43:06 +01:00
device-hotplug.c blockdev: Remove unused DriveInfo reference count 2014-06-16 17:23:19 +08:00
device_tree.c device_tree.c: dump all err mesages with error_report 2014-09-02 22:38:16 +04:00
disas.c monitor: QEMU Monitor Instruction Disassembly Incorrect for PowerPC LE Mode 2014-06-16 13:24:26 +02:00
dma-helpers.c block: Rename qemu_aio_release -> qemu_aio_unref 2014-09-22 11:39:17 +01:00
dump.c dump.c: Fix memory leak issue in cleanup processing for dump_init() 2014-08-18 14:39:10 -04:00
exec.c exec.c: fix setting 1-byte-long watchpoints 2014-09-19 17:42:16 +01:00
gdbstub.c gdbstub: Allow target CPUs to specify watchpoint STOP_BEFORE_ACCESS flag 2014-10-06 14:25:43 +01:00
hmp-commands.hx Add HMP command "info memory-devices" 2014-09-26 13:37:06 -04:00
hmp.c Add HMP command "info memory-devices" 2014-09-26 13:37:06 -04:00
hmp.h Add HMP command "info memory-devices" 2014-09-26 13:37:06 -04:00
iohandler.c iohandler.c: Properly initialize sigaction struct 2014-05-24 00:07:29 +04:00
ioport.c memory: convert memory_region_destroy to object_unparent 2014-08-18 12:06:20 +02:00
iothread.c async: aio_context_new(): Handle event_notifier_init failure 2014-09-22 11:39:48 +01:00
kvm-all.c kvm fix compilation with GCC 4.3.4 2014-10-10 14:07:08 +01:00
kvm-stub.c accel: Move KVM accel registration to kvm-all.c 2014-10-04 08:59:15 +02:00
main-loop.c main-loop.c: Handle SIGINT, SIGHUP and SIGTERM synchronously 2014-09-26 11:47:30 +01:00
memory.c memory: add parameter errp to memory_region_init_rom_device 2014-09-09 13:41:44 +02:00
memory_mapping.c
migration-exec.c
migration-fd.c
migration-rdma.c rdma: Fix incorrect description in comments 2014-09-20 17:55:53 +04:00
migration-tcp.c qemu-sockets: Add error to non-blocking connect handler 2014-10-09 15:36:15 +02:00
migration-unix.c qemu-sockets: Add error to non-blocking connect handler 2014-10-09 15:36:15 +02:00
migration.c block/migration: Disable cache invalidate for incoming migration 2014-10-14 09:35:21 +02:00
module-common.c
monitor.c Add HMP command "info memory-devices" 2014-09-26 13:37:06 -04:00
nbd.c block/migration: Disable cache invalidate for incoming migration 2014-10-14 09:35:21 +02:00
numa.c memory: add parameter errp to memory_region_init_ram 2014-09-09 13:41:43 +02:00
os-posix.c os-posix: report error message when lock file failed 2014-09-26 21:21:09 +04:00
os-win32.c
page_cache.c migration: Plug memory leak in migrate-set-cache-size command 2014-06-10 19:54:43 +04:00
qapi-schema.json qmp: Print descriptions of object properties 2014-10-15 05:03:15 +02:00
qdev-monitor.c qmp: Print descriptions of object properties 2014-10-15 05:03:15 +02:00
qdict-test-data.txt
qemu-bridge-helper.c qemu-bridge-helper: Fix fd leak in main() 2014-06-27 10:39:10 +02:00
qemu-char.c qemu-char: Fix reconnect socket error reporting 2014-10-09 15:36:15 +02:00
qemu-coroutine-io.c qemu-coroutine-io: fix for Win32 2014-08-29 10:46:58 +01:00
qemu-coroutine-lock.c
qemu-coroutine-sleep.c coroutine: Drop co_sleep_ns 2014-08-29 10:46:58 +01:00
qemu-coroutine.c coroutine: make pool size dynamic 2014-08-15 15:07:14 +02:00
qemu-doc.texi block: delete cow block driver 2014-09-22 11:39:45 +01:00
qemu-file-stdio.c qemu-file: Move stdio implementation to qemu-file-stdio.c 2014-10-14 10:29:28 +02:00
qemu-file-unix.c qemu-file: Move unix and socket implementations to qemu-file-unix.c 2014-10-14 10:29:28 +02:00
qemu-file.c qemu-file: Move stdio implementation to qemu-file-stdio.c 2014-10-14 10:29:28 +02:00
qemu-img-cmds.hx qemu-img: Allow cache mode specification for amend 2014-08-22 14:54:48 +02:00
qemu-img.c block: New BlockBackend 2014-10-20 13:41:26 +02:00
qemu-img.texi block: delete cow block driver 2014-09-22 11:39:45 +01:00
qemu-io-cmds.c qemu-io-cmds: g_renew() can't fail, bury dead error handling 2014-08-20 11:51:28 +02:00
qemu-io.c block: New BlockBackend 2014-10-20 13:41:26 +02:00
qemu-log.c
qemu-nbd.c block: New BlockBackend 2014-10-20 13:41:26 +02:00
qemu-nbd.texi nbd: Miscellaneous typo fixes. 2014-05-24 00:07:29 +04:00
qemu-options-wrapper.h
qemu-options.h
qemu-options.hx qemu-char: Add reconnecting to client sockets 2014-10-04 08:59:14 +02:00
qemu-seccomp.c seccomp: add semctl() to the syscall whitelist 2014-08-21 10:29:16 +02:00
qemu-tech.texi
qemu-timer.c vl.c: remove init_clocks call from main 2014-05-09 20:57:32 +02:00
qemu.nsi
qemu.sasl
qmp-commands.hx add input-send-event command 2014-10-02 09:58:14 +02:00
qmp.c qmp: Print descriptions of object properties 2014-10-15 05:03:15 +02:00
qtest.c accel: Pass MachineState object to accel init functions 2014-10-09 12:57:10 +02:00
rules.mak Fix cross compilation (nm command) 2014-09-19 17:20:11 +01:00
savevm.c snapshot: fix referencing wrong variable in while loop in do_delvm 2014-10-03 10:30:33 +01:00
softmmu_template.h implementing victim TLB for QEMU system emulated TLB 2014-09-01 17:43:06 +01:00
spice-qemu-char.c qemu-char: Rename register_char_driver_qapi() to register_char_driver() 2014-09-16 23:36:32 +01:00
tcg-runtime.c tcg: Push tcg-runtime routines into exec/helper-* 2014-05-28 09:33:54 -07:00
tci.c Merge remote-tracking branch 'remotes/bonzini/softmmu-smap' into staging 2014-06-05 21:06:14 +01:00
thread-pool.c block: Rename qemu_aio_release -> qemu_aio_unref 2014-09-22 11:39:17 +01:00
thunk.c
tpm.c
trace-events s390x/kvm: propagate s390 cpu state to kvm 2014-10-10 10:37:47 +02:00
translate-all.c translate-all.c: memory walker initial address miscalculation 2014-10-06 21:53:35 +03:00
translate-all.h
user-exec.c softmmu: introduce cpu_ldst.h 2014-06-05 16:10:33 +02:00
version.rc
vl.c bootdevice: move bootdevice related code to new file bootdevice.c 2014-10-15 09:49:48 +02:00
vmstate.c vmstate: Allow dynamic allocation for VBUFFER during migration 2014-10-14 09:35:48 +02:00
xbzrle.c
xen-common-stub.c accel: Move Xen registration code to xen-common.c 2014-10-04 08:59:15 +02:00
xen-common.c accel: Pass MachineState object to accel init functions 2014-10-09 12:57:10 +02:00
xen-hvm-stub.c xen-hvm: Fix xen_hvm_init() to adjust pc memory layout 2014-06-23 17:50:04 +03:00
xen-hvm.c xen-hvm.c: Always return -1 when failure occurs in xen_hvm_init() 2014-09-20 17:55:53 +04:00
xen-mapcache.c xen: build on ARM 2014-07-07 10:37:40 +00:00

README

Read the documentation in qemu-doc.html or on http://wiki.qemu-project.org

- QEMU team