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5bb0474778
bs->file and bs->backing are a kind of duplication of part of
bs->children. But very useful diplication, so let's not drop them at
all:)
We should manage bs->file and bs->backing in same place, where we
manage bs->children, to keep them in sync.
Moreover, generic io paths are unprepared to BdrvChild without a bs, so
it's double good to clear bs->file / bs->backing when we detach the
child.
Detach is simple: if we detach bs->file or bs->backing child, just
set corresponding field to NULL.
Attach is a bit more complicated. But we still can precisely detect
should we set one of bs->file / bs->backing or not:
- if role is BDRV_CHILD_COW, we definitely deal with bs->backing
- else, if role is BDRV_CHILD_FILTERED (it must be also
BDRV_CHILD_PRIMARY), it's a filtered child. Use
bs->drv->filtered_child_is_backing to chose the pointer field to
modify.
- else, if role is BDRV_CHILD_PRIMARY, we deal with bs->file
- in all other cases, it's neither bs->backing nor bs->file. It's some
other child and we shouldn't care
OK. This change brings one more good thing: we can (and should) get rid
of all indirect pointers in the block-graph-change transactions:
bdrv_attach_child_common() stores BdrvChild** into transaction to clear
it on abort.
bdrv_attach_child_common() has two callers: bdrv_attach_child_noperm()
just pass-through this feature, bdrv_root_attach_child() doesn't need
the feature.
Look at bdrv_attach_child_noperm() callers:
- bdrv_attach_child() doesn't need the feature
- bdrv_set_file_or_backing_noperm() uses the feature to manage
bs->file and bs->backing, we don't want it anymore
- bdrv_append() uses the feature to manage bs->backing, again we
don't want it anymore
So, we should drop this stuff! Great!
We could probably keep BdrvChild** argument to keep the int return
value, but it seems not worth the complexity.
Finally, we now set .file / .backing automatically in generic code and
want to restring setting them by hand outside of .attach/.detach.
So, this patch cleanups all remaining places where they were set.
To find such places I use:
git grep '\->file ='
git grep '\->backing ='
git grep '&.*\<backing\>'
git grep '&.*\<file\>'
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Reviewed-by: Hanna Reitz <hreitz@redhat.com>
Message-Id: <20220726201134.924743-14-vsementsov@yandex-team.ru>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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| .. | ||
| check-block-qdict.c | ||
| check-qdict.c | ||
| check-qjson.c | ||
| check-qlist.c | ||
| check-qlit.c | ||
| check-qnull.c | ||
| check-qnum.c | ||
| check-qobject.c | ||
| check-qom-interface.c | ||
| check-qom-proplist.c | ||
| check-qstring.c | ||
| crypto-tls-psk-helpers.c | ||
| crypto-tls-psk-helpers.h | ||
| crypto-tls-x509-helpers.c | ||
| crypto-tls-x509-helpers.h | ||
| io-channel-helpers.c | ||
| io-channel-helpers.h | ||
| iothread.c | ||
| iothread.h | ||
| meson.build | ||
| pkix_asn1_tab.c | ||
| ptimer-test-stubs.c | ||
| ptimer-test.c | ||
| ptimer-test.h | ||
| rcutorture.c | ||
| socket-helpers.c | ||
| socket-helpers.h | ||
| test-aio-multithread.c | ||
| test-aio.c | ||
| test-authz-list.c | ||
| test-authz-listfile.c | ||
| test-authz-pam.c | ||
| test-authz-simple.c | ||
| test-base64.c | ||
| test-bdrv-drain.c | ||
| test-bdrv-graph-mod.c | ||
| test-bitcnt.c | ||
| test-bitmap.c | ||
| test-bitops.c | ||
| test-block-backend.c | ||
| test-block-iothread.c | ||
| test-blockjob-txn.c | ||
| test-blockjob.c | ||
| test-bufferiszero.c | ||
| test-char.c | ||
| test-clone-visitor.c | ||
| test-coroutine.c | ||
| test-crypto-afsplit.c | ||
| test-crypto-akcipher.c | ||
| test-crypto-block.c | ||
| test-crypto-cipher.c | ||
| test-crypto-der.c | ||
| test-crypto-hash.c | ||
| test-crypto-hmac.c | ||
| test-crypto-ivgen.c | ||
| test-crypto-pbkdf.c | ||
| test-crypto-secret.c | ||
| test-crypto-tlscredsx509.c | ||
| test-crypto-tlssession.c | ||
| test-crypto-xts.c | ||
| test-cutils.c | ||
| test-div128.c | ||
| test-fdmon-epoll.c | ||
| test-forward-visitor.c | ||
| test-hbitmap.c | ||
| test-image-locking.c | ||
| test-int128.c | ||
| test-io-channel-buffer.c | ||
| test-io-channel-command.c | ||
| test-io-channel-file.c | ||
| test-io-channel-null.c | ||
| test-io-channel-socket.c | ||
| test-io-channel-tls.c | ||
| test-io-task.c | ||
| test-iov.c | ||
| test-keyval.c | ||
| test-logging.c | ||
| test-mul64.c | ||
| test-opts-visitor.c | ||
| test-qapi-util.c | ||
| test-qdev-global-props.c | ||
| test-qdist.c | ||
| test-qemu-opts.c | ||
| test-qga.c | ||
| test-qgraph.c | ||
| test-qht.c | ||
| test-qmp-cmds.c | ||
| test-qmp-event.c | ||
| test-qobject-input-visitor.c | ||
| test-qobject-output-visitor.c | ||
| test-rcu-list.c | ||
| test-rcu-simpleq.c | ||
| test-rcu-slist.c | ||
| test-rcu-tailq.c | ||
| test-replication.c | ||
| test-seccomp.c | ||
| test-shift128.c | ||
| test-smp-parse.c | ||
| test-string-input-visitor.c | ||
| test-string-output-visitor.c | ||
| test-thread-pool.c | ||
| test-throttle.c | ||
| test-timed-average.c | ||
| test-util-filemonitor.c | ||
| test-util-sockets.c | ||
| test-uuid.c | ||
| test-visitor-serialization.c | ||
| test-vmstate.c | ||
| test-write-threshold.c | ||
| test-x86-cpuid.c | ||
| test-xbzrle.c | ||
| test-yank.c | ||