[PATCH for-5.0 00/31] block: Introduce real BdrvChildRole

From: Max Reitz <mreitz@redhat.com>
To: qemu-block@nongnu.org
Cc: Kevin Wolf <kwolf@redhat.com>,
	qemu-devel@nongnu.org, Max Reitz <mreitz@redhat.com>
Subject: [PATCH for-5.0 00/31] block: Introduce real BdrvChildRole
Date: Wed, 27 Nov 2019 14:15:53 +0100	[thread overview]
Message-ID: <20191127131624.1062403-1-mreitz@redhat.com> (raw)

Based-on: <20191111160216.197086-1-mreitz@redhat.com>
(“block: Fix check_to_replace_node()”)

This is preliminary work for v7 of “Deal with filters”.  As Kevin has
noted, there may be e.g. multiple storage children, and there should
probably be some way for drivers to signal what they use each child for.

Before this series, this is done in a way with the child_* BdrvChildRole
objects (i.e., child_file, child_format, child_backing).  However, they
don’t really suit that task, for multiple reasons:
(1) They don’t formally mean anything.
(2) Drivers may or may not use them.  We have tests that just copy
    child_backing and overwrite a single callback to suit their need.
(3) You can’t combine them (e.g. for children that store both data and
    metadata).

The current BdrvChildRole structure is really just a way to contact the
parent about any changes regarding the child, so it doesn’t describe a
role but a class.  Hence this series renames it to BdrvChildClass.

Then we can introduce a real BdrvChildRole, which is an enum that
captures the roles a child can have in a bit field, so they can be
combined.

It turns out that we can use this role to unify child_file,
child_format, and child_backing into a generic child_of_bds class that
can decide what to do for each child (e.g. when it comes to flag
inheritance) based on the BdrvChildRole.

This also applies to bdrv_format_default_perms() and
bdrv_filter_default_perms(): We can unify them in a generic
bdrv_filter_perms() that has different paths for filtered, backing,
metadata, and pure-data children.

Max Reitz (31):
  block: Rename BdrvChildRole to BdrvChildClass
  block: Add BdrvChildRole
  block: Add BdrvChildRole to BdrvChild
  block: Pass BdrvChildRole to bdrv_child_perm()
  block: Drop BdrvChildClass.stay_at_node
  block: Keep BDRV_O_NO_IO in *inherited_fmt_options
  block: Pass BdrvChildRole to .inherit_options()
  block: Unify bdrv_*inherited_options()
  block: Unify bdrv_child_cb_attach()
  block: Unify bdrv_child_cb_detach()
  block: Add child_of_bds
  block: Distinguish paths in *_format_default_perms
  block: Pull out bdrv_default_perms_for_backing()
  block: Pull out bdrv_default_perms_for_storage()
  block: Split bdrv_default_perms_for_storage()
  block: Add bdrv_default_perms()
  raw-format: Split raw_read_options()
  block: Switch child_format users to child_of_bds
  block: Drop child_format
  block: Make backing files child_of_bds children
  block: Drop child_backing
  block: Make format drivers use child_of_bds
  block: Make filter drivers use child_of_bds
  block: Use child_of_bds in remaining places
  tests: Use child_of_bds instead of child_file
  block: Use bdrv_default_perms()
  block: Make bdrv_filter_default_perms() static
  block: Drop bdrv_format_default_perms()
  block: Drop child_file
  block: Pass BdrvChildRole in remaining cases
  block: Drop @child_class from bdrv_child_perm()

 block.c                     | 477 +++++++++++++++++++++---------------
 block/backup-top.c          |  11 +-
 block/blkdebug.c            |  10 +-
 block/blklogwrites.c        |  17 +-
 block/blkreplay.c           |   7 +-
 block/blkverify.c           |  12 +-
 block/block-backend.c       |  20 +-
 block/bochs.c               |   6 +-
 block/cloop.c               |   6 +-
 block/commit.c              |   2 +-
 block/copy-on-read.c        |   7 +-
 block/crypto.c              |   6 +-
 block/dmg.c                 |   6 +-
 block/io.c                  |  22 +-
 block/mirror.c              |   2 +-
 block/parallels.c           |   6 +-
 block/qcow.c                |   6 +-
 block/qcow2.c               |  20 +-
 block/qed.c                 |   6 +-
 block/quorum.c              |  11 +-
 block/raw-format.c          | 128 ++++++----
 block/replication.c         |   5 +-
 block/throttle.c            |   7 +-
 block/vdi.c                 |   6 +-
 block/vhdx.c                |   6 +-
 block/vmdk.c                |  22 +-
 block/vpc.c                 |   6 +-
 block/vvfat.c               |  11 +-
 blockjob.c                  |   8 +-
 include/block/block.h       |  46 +++-
 include/block/block_int.h   |  54 ++--
 tests/test-bdrv-drain.c     |  72 +++---
 tests/test-bdrv-graph-mod.c |  10 +-
 tests/test-block-iothread.c |  17 +-
 34 files changed, 625 insertions(+), 433 deletions(-)

-- 
2.23.0