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* [PATCH v4 00/34] block: Introduce real BdrvChildRole
@ 2020-05-13 11:05 Max Reitz
  2020-05-13 11:05 ` [PATCH v4 01/34] block: Mark commit, mirror, blkreplay as filters Max Reitz
                   ` (35 more replies)
  0 siblings, 36 replies; 54+ messages in thread
From: Max Reitz @ 2020-05-13 11:05 UTC (permalink / raw)
  To: qemu-block; +Cc: Kevin Wolf, qemu-devel, Max Reitz

Based-on: <20200429141126.85159-1-mreitz@redhat.com>
(“block: Do not call BlockDriver.bdrv_make_empty() directly”)

Branch: https://github.com/XanClic/qemu.git child-role-v4
Branch: https://git.xanclic.moe/XanClic/qemu.git child-role-v4

v1: https://lists.nongnu.org/archive/html/qemu-block/2019-11/msg00908.html
v2: https://lists.nongnu.org/archive/html/qemu-block/2020-02/msg00108.html
v3: https://lists.nongnu.org/archive/html/qemu-block/2020-02/msg00737.html


Hi,

For the “why” and “what” regarding this series, see the cover letter of
v1 (linked above).


In v4, I mostly addressed Kevin’s comments (and one permission bug for
pure data children in patch 18):
- Patch 1: Pulled in from the “Deal with filters” series (and added
           blkreplay to the mix)

- Patch 4: More comments, and added consistent notes on how many
           children may get a certain role

- Patch 10:
  - Move the function down below child_backing, so that we get less
    forward declarations of static functions, and they’ll all be
    temporary
  - Split the (role & (DATA | METADATA | FILTERED)) == DATA condition
    into (role & DATA) && !(role & (METADATA | FILTERED))
  - Fixed up the comment on how backing files are opened RO only by
    default
  - Unconditionally let @unmap default to true for children

- Patch 11: Fallout from having moved bdrv_inherited_options() down: We
            need a forward declaration of bdrv_open_inherit()

- Patch 12: Move bdrv_child_cb_attach() down to
            bdrv_inherited_options(), and add a (temporary) forward
            declaration for it

- Patch 13: Same as patch 12, but for bdrv_child_detach() now

- Patch 14: Drop (now unnecessary) forward declaration of
            bdrv_backing_update_filename()

- Patch 16: Renamed s/for_backing/for_cow/

- Patch 18: Swapped the existing patch that split
            bdrv_default_perms_for_storage() function into for_data()
            and for_metadata() for this one, which handles both cases in
            the existing function, but just relaxes the restrictions for
            pure data children
  - Also, some permissions fixed: When WRITE_UNCHANGED was taken on the
    parent, it may need WRITE on the the data child; and if it needs
    WRITE, it may also need RESIZE.

- Patch 19:
  - Fallout from bdrv_default_perms_for_storage() still being a single
    function
  - Assertions that FILTERED, COW, and DATA | METADATA are mutually
    exclusive

- Patch 23: Use bdrv_backing_role() instead of a fixed BDRV_CHILD_COW in
            bdrv_open_backing_file()

- Patch 24: Fallout from bdrv_default_perms_for_storage() still being a
            single function

- Patch 26: blkreplay is a filter now, too

- Patch 27: Drop blkreplay (it’s now a filter, so handled in patch 26)

- Patch 31: Fallout from bdrv_default_perms_for_storage() still being a
            single function

- Patch 32:
  - Fallout from bdrv_default_perms_for_storage() still being a single
    function
  - Remove the temporary forward declarations added in patches 11
    through 13

- Patch 33: Pass DATA | METADATA instead of just DATA for vvfat’s qcow
            child

- Patch 34:
  - Fallout from bdrv_default_perms_for_backing() being named
    bdrv_default_perms_for_cow() now
  - Fallout from bdrv_default_perms_for_storage() still being a single
    function


git-backport-diff against v3:

Key:
[----] : patches are identical
[####] : number of functional differences between upstream/downstream patch
[down] : patch is downstream-only
The flags [FC] indicate (F)unctional and (C)ontextual differences, respectively

001/34:[down] 'block: Mark commit, mirror, blkreplay as filters'
002/34:[----] [--] 'block: Add BlockDriver.is_format'
003/34:[----] [-C] 'block: Rename BdrvChildRole to BdrvChildClass'
004/34:[0030] [FC] 'block: Add BdrvChildRole and BdrvChildRoleBits'
005/34:[----] [-C] 'block: Add BdrvChildRole to BdrvChild'
006/34:[----] [--] 'block: Pass BdrvChildRole to bdrv_child_perm()'
007/34:[----] [-C] 'block: Pass BdrvChildRole to .inherit_options()'
008/34:[----] [--] 'block: Pass parent_is_format to .inherit_options()'
009/34:[----] [--] 'block: Rename bdrv_inherited_options()'
010/34:[0021] [FC] 'block: Add generic bdrv_inherited_options()'
011/34:[0015] [FC] 'block: Use bdrv_inherited_options()'
012/34:[0025] [FC] 'block: Unify bdrv_child_cb_attach()'
013/34:[0024] [FC] 'block: Unify bdrv_child_cb_detach()'
014/34:[0003] [FC] 'block: Add child_of_bds'
015/34:[----] [--] 'block: Distinguish paths in *_format_default_perms'
016/34:[0016] [FC] 'block: Pull out bdrv_default_perms_for_cow()'
017/34:[----] [-C] 'block: Pull out bdrv_default_perms_for_storage()'
018/34:[down] 'block: Relax *perms_for_storage for data children'
019/34:[0028] [FC] 'block: Add bdrv_default_perms()'
020/34:[----] [--] 'raw-format: Split raw_read_options()'
021/34:[----] [--] 'block: Switch child_format users to child_of_bds'
022/34:[----] [--] 'block: Drop child_format'
023/34:[0002] [FC] 'block: Make backing files child_of_bds children'
024/34:[0010] [FC] 'block: Drop child_backing'
025/34:[----] [--] 'block: Make format drivers use child_of_bds'
026/34:[0005] [FC] 'block: Make filter drivers use child_of_bds'
027/34:[0005] [FC] 'block: Use child_of_bds in remaining places'
028/34:[----] [--] 'tests: Use child_of_bds instead of child_file'
029/34:[----] [-C] 'block: Use bdrv_default_perms()'
030/34:[----] [--] 'block: Make bdrv_filter_default_perms() static'
031/34:[0004] [FC] 'block: Drop bdrv_format_default_perms()'
032/34:[0013] [FC] 'block: Drop child_file'
033/34:[0004] [FC] 'block: Pass BdrvChildRole in remaining cases'
034/34:[0024] [FC] 'block: Drop @child_class from bdrv_child_perm()'


Max Reitz (34):
  block: Mark commit, mirror, blkreplay as filters
  block: Add BlockDriver.is_format
  block: Rename BdrvChildRole to BdrvChildClass
  block: Add BdrvChildRole and BdrvChildRoleBits
  block: Add BdrvChildRole to BdrvChild
  block: Pass BdrvChildRole to bdrv_child_perm()
  block: Pass BdrvChildRole to .inherit_options()
  block: Pass parent_is_format to .inherit_options()
  block: Rename bdrv_inherited_options()
  block: Add generic bdrv_inherited_options()
  block: Use 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_cow()
  block: Pull out bdrv_default_perms_for_storage()
  block: Relax *perms_for_storage for data children
  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()

 include/block/block.h       |  64 +++-
 include/block/block_int.h   |  57 ++--
 block.c                     | 578 ++++++++++++++++++++++--------------
 block/backup-top.c          |  11 +-
 block/blkdebug.c            |  10 +-
 block/blklogwrites.c        |  16 +-
 block/blkreplay.c           |   8 +-
 block/blkverify.c           |  10 +-
 block/block-backend.c       |  20 +-
 block/bochs.c               |   7 +-
 block/cloop.c               |   7 +-
 block/commit.c              |   4 +-
 block/copy-on-read.c        |   7 +-
 block/crypto.c              |   8 +-
 block/dmg.c                 |   7 +-
 block/filter-compress.c     |   7 +-
 block/io.c                  |  22 +-
 block/mirror.c              |   4 +-
 block/parallels.c           |   7 +-
 block/qcow.c                |   7 +-
 block/qcow2.c               |  20 +-
 block/qed.c                 |   7 +-
 block/quorum.c              |   8 +-
 block/raw-format.c          | 128 +++++---
 block/replication.c         |   5 +-
 block/throttle.c            |   7 +-
 block/vdi.c                 |   7 +-
 block/vhdx.c                |   7 +-
 block/vmdk.c                |  23 +-
 block/vpc.c                 |   7 +-
 block/vvfat.c               |  13 +-
 blockjob.c                  |   7 +-
 tests/test-bdrv-drain.c     |  72 ++---
 tests/test-bdrv-graph-mod.c |  10 +-
 tests/test-block-iothread.c |  17 +-
 35 files changed, 738 insertions(+), 461 deletions(-)

-- 
2.26.2



^ permalink raw reply	[flat|nested] 54+ messages in thread

* [PATCH v4 01/34] block: Mark commit, mirror, blkreplay as filters
  2020-05-13 11:05 [PATCH v4 00/34] block: Introduce real BdrvChildRole Max Reitz
@ 2020-05-13 11:05 ` Max Reitz
  2020-05-13 11:05 ` [PATCH v4 02/34] block: Add BlockDriver.is_format Max Reitz
                   ` (34 subsequent siblings)
  35 siblings, 0 replies; 54+ messages in thread
From: Max Reitz @ 2020-05-13 11:05 UTC (permalink / raw)
  To: qemu-block; +Cc: Kevin Wolf, qemu-devel, Max Reitz

The commit, mirror, and blkreplay block nodes are filters, so they should
be marked as such.

Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 block/blkreplay.c | 1 +
 block/commit.c    | 2 ++
 block/mirror.c    | 2 ++
 3 files changed, 5 insertions(+)

diff --git a/block/blkreplay.c b/block/blkreplay.c
index c96ac8f4bc..131c9e8477 100644
--- a/block/blkreplay.c
+++ b/block/blkreplay.c
@@ -135,6 +135,7 @@ static int blkreplay_snapshot_goto(BlockDriverState *bs,
 static BlockDriver bdrv_blkreplay = {
     .format_name            = "blkreplay",
     .instance_size          = 0,
+    .is_filter              = true,
 
     .bdrv_open              = blkreplay_open,
     .bdrv_child_perm        = bdrv_filter_default_perms,
diff --git a/block/commit.c b/block/commit.c
index ba60fb7955..b0a8a793cd 100644
--- a/block/commit.c
+++ b/block/commit.c
@@ -240,6 +240,8 @@ static BlockDriver bdrv_commit_top = {
     .bdrv_co_block_status       = bdrv_co_block_status_from_backing,
     .bdrv_refresh_filename      = bdrv_commit_top_refresh_filename,
     .bdrv_child_perm            = bdrv_commit_top_child_perm,
+
+    .is_filter                  = true,
 };
 
 void commit_start(const char *job_id, BlockDriverState *bs,
diff --git a/block/mirror.c b/block/mirror.c
index 201ffa26f9..55e992670a 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -1530,6 +1530,8 @@ static BlockDriver bdrv_mirror_top = {
     .bdrv_co_block_status       = bdrv_co_block_status_from_backing,
     .bdrv_refresh_filename      = bdrv_mirror_top_refresh_filename,
     .bdrv_child_perm            = bdrv_mirror_top_child_perm,
+
+    .is_filter                  = true,
 };
 
 static BlockJob *mirror_start_job(
-- 
2.26.2



^ permalink raw reply related	[flat|nested] 54+ messages in thread

* [PATCH v4 02/34] block: Add BlockDriver.is_format
  2020-05-13 11:05 [PATCH v4 00/34] block: Introduce real BdrvChildRole Max Reitz
  2020-05-13 11:05 ` [PATCH v4 01/34] block: Mark commit, mirror, blkreplay as filters Max Reitz
@ 2020-05-13 11:05 ` Max Reitz
  2020-05-13 11:05 ` [PATCH v4 03/34] block: Rename BdrvChildRole to BdrvChildClass Max Reitz
                   ` (33 subsequent siblings)
  35 siblings, 0 replies; 54+ messages in thread
From: Max Reitz @ 2020-05-13 11:05 UTC (permalink / raw)
  To: qemu-block; +Cc: Kevin Wolf, qemu-devel, Max Reitz

We want to unify child_format and child_file at some point.  One of the
important things that set format drivers apart from other drivers is
that they do not expect other format nodes under them (except in the
backing chain), i.e. we must not probe formats inside of formats.  That
means we need something on which to distinguish format drivers from
others, and hence this flag.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
---
 include/block/block_int.h | 7 +++++++
 block/bochs.c             | 1 +
 block/cloop.c             | 1 +
 block/crypto.c            | 2 ++
 block/dmg.c               | 1 +
 block/parallels.c         | 1 +
 block/qcow.c              | 1 +
 block/qcow2.c             | 1 +
 block/qed.c               | 1 +
 block/raw-format.c        | 1 +
 block/vdi.c               | 1 +
 block/vhdx.c              | 1 +
 block/vmdk.c              | 1 +
 block/vpc.c               | 1 +
 14 files changed, 21 insertions(+)

diff --git a/include/block/block_int.h b/include/block/block_int.h
index 7ba8c89036..1c24df53fd 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -95,6 +95,13 @@ struct BlockDriver {
      * must implement them and return -ENOTSUP.
      */
     bool is_filter;
+    /*
+     * Set to true if the BlockDriver is a format driver.  Format nodes
+     * generally do not expect their children to be other format nodes
+     * (except for backing files), and so format probing is disabled
+     * on those children.
+     */
+    bool is_format;
     /*
      * Return true if @to_replace can be replaced by a BDS with the
      * same data as @bs without it affecting @bs's behavior (that is,
diff --git a/block/bochs.c b/block/bochs.c
index 32bb83b268..e7bbeaa1c4 100644
--- a/block/bochs.c
+++ b/block/bochs.c
@@ -301,6 +301,7 @@ static BlockDriver bdrv_bochs = {
     .bdrv_refresh_limits = bochs_refresh_limits,
     .bdrv_co_preadv = bochs_co_preadv,
     .bdrv_close		= bochs_close,
+    .is_format          = true,
 };
 
 static void bdrv_bochs_init(void)
diff --git a/block/cloop.c b/block/cloop.c
index 4de94876d4..f90f1a4b4c 100644
--- a/block/cloop.c
+++ b/block/cloop.c
@@ -297,6 +297,7 @@ static BlockDriver bdrv_cloop = {
     .bdrv_refresh_limits = cloop_refresh_limits,
     .bdrv_co_preadv = cloop_co_preadv,
     .bdrv_close     = cloop_close,
+    .is_format      = true,
 };
 
 static void bdrv_cloop_init(void)
diff --git a/block/crypto.c b/block/crypto.c
index 6b21d6bf6c..bdb2b27475 100644
--- a/block/crypto.c
+++ b/block/crypto.c
@@ -771,6 +771,8 @@ static BlockDriver bdrv_crypto_luks = {
     .bdrv_get_info      = block_crypto_get_info_luks,
     .bdrv_get_specific_info = block_crypto_get_specific_info_luks,
 
+    .is_format          = true,
+
     .strong_runtime_opts = block_crypto_strong_runtime_opts,
 };
 
diff --git a/block/dmg.c b/block/dmg.c
index 4a045f2b3e..ef3c6e771d 100644
--- a/block/dmg.c
+++ b/block/dmg.c
@@ -753,6 +753,7 @@ static BlockDriver bdrv_dmg = {
     .bdrv_child_perm     = bdrv_format_default_perms,
     .bdrv_co_preadv = dmg_co_preadv,
     .bdrv_close     = dmg_close,
+    .is_format      = true,
 };
 
 static void bdrv_dmg_init(void)
diff --git a/block/parallels.c b/block/parallels.c
index e7717c508e..bd5f6ffa09 100644
--- a/block/parallels.c
+++ b/block/parallels.c
@@ -918,6 +918,7 @@ static BlockDriver bdrv_parallels = {
     .bdrv_co_flush_to_os      = parallels_co_flush_to_os,
     .bdrv_co_readv  = parallels_co_readv,
     .bdrv_co_writev = parallels_co_writev,
+    .is_format      = true,
     .supports_backing = true,
     .bdrv_co_create      = parallels_co_create,
     .bdrv_co_create_opts = parallels_co_create_opts,
diff --git a/block/qcow.c b/block/qcow.c
index b0475b73a5..6a72dea049 100644
--- a/block/qcow.c
+++ b/block/qcow.c
@@ -1185,6 +1185,7 @@ static BlockDriver bdrv_qcow = {
     .bdrv_co_create         = qcow_co_create,
     .bdrv_co_create_opts    = qcow_co_create_opts,
     .bdrv_has_zero_init     = bdrv_has_zero_init_1,
+    .is_format              = true,
     .supports_backing       = true,
     .bdrv_refresh_limits    = qcow_refresh_limits,
 
diff --git a/block/qcow2.c b/block/qcow2.c
index ad9ab4fafa..76bec61ee9 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -5767,6 +5767,7 @@ BlockDriver bdrv_qcow2 = {
     .bdrv_save_vmstate    = qcow2_save_vmstate,
     .bdrv_load_vmstate    = qcow2_load_vmstate,
 
+    .is_format                  = true,
     .supports_backing           = true,
     .bdrv_change_backing_file   = qcow2_change_backing_file,
 
diff --git a/block/qed.c b/block/qed.c
index 5da9726518..337eb6dbb6 100644
--- a/block/qed.c
+++ b/block/qed.c
@@ -1665,6 +1665,7 @@ static BlockDriver bdrv_qed = {
     .format_name              = "qed",
     .instance_size            = sizeof(BDRVQEDState),
     .create_opts              = &qed_create_opts,
+    .is_format                = true,
     .supports_backing         = true,
 
     .bdrv_probe               = bdrv_qed_probe,
diff --git a/block/raw-format.c b/block/raw-format.c
index 9108e43696..00e13bb41e 100644
--- a/block/raw-format.c
+++ b/block/raw-format.c
@@ -566,6 +566,7 @@ BlockDriver bdrv_raw = {
     .bdrv_co_copy_range_to  = &raw_co_copy_range_to,
     .bdrv_co_truncate     = &raw_co_truncate,
     .bdrv_getlength       = &raw_getlength,
+    .is_format            = true,
     .has_variable_length  = true,
     .bdrv_measure         = &raw_measure,
     .bdrv_get_info        = &raw_get_info,
diff --git a/block/vdi.c b/block/vdi.c
index 2d28046615..0ef733ae19 100644
--- a/block/vdi.c
+++ b/block/vdi.c
@@ -1053,6 +1053,7 @@ static BlockDriver bdrv_vdi = {
 
     .bdrv_get_info = vdi_get_info,
 
+    .is_format = true,
     .create_opts = &vdi_create_opts,
     .bdrv_co_check = vdi_co_check,
 };
diff --git a/block/vhdx.c b/block/vhdx.c
index 53e756438a..e692cf80cc 100644
--- a/block/vhdx.c
+++ b/block/vhdx.c
@@ -2254,6 +2254,7 @@ static BlockDriver bdrv_vhdx = {
     .bdrv_co_check          = vhdx_co_check,
     .bdrv_has_zero_init     = vhdx_has_zero_init,
 
+    .is_format              = true,
     .create_opts            = &vhdx_create_opts,
 };
 
diff --git a/block/vmdk.c b/block/vmdk.c
index b18f128816..56e85689f3 100644
--- a/block/vmdk.c
+++ b/block/vmdk.c
@@ -3070,6 +3070,7 @@ static BlockDriver bdrv_vmdk = {
     .bdrv_get_info                = vmdk_get_info,
     .bdrv_gather_child_options    = vmdk_gather_child_options,
 
+    .is_format                    = true,
     .supports_backing             = true,
     .create_opts                  = &vmdk_create_opts,
 };
diff --git a/block/vpc.c b/block/vpc.c
index 5e31dd1e47..46a2d48659 100644
--- a/block/vpc.c
+++ b/block/vpc.c
@@ -1250,6 +1250,7 @@ static BlockDriver bdrv_vpc = {
 
     .bdrv_get_info          = vpc_get_info,
 
+    .is_format              = true,
     .create_opts            = &vpc_create_opts,
     .bdrv_has_zero_init     = vpc_has_zero_init,
     .strong_runtime_opts    = vpc_strong_runtime_opts,
-- 
2.26.2



^ permalink raw reply related	[flat|nested] 54+ messages in thread

* [PATCH v4 03/34] block: Rename BdrvChildRole to BdrvChildClass
  2020-05-13 11:05 [PATCH v4 00/34] block: Introduce real BdrvChildRole Max Reitz
  2020-05-13 11:05 ` [PATCH v4 01/34] block: Mark commit, mirror, blkreplay as filters Max Reitz
  2020-05-13 11:05 ` [PATCH v4 02/34] block: Add BlockDriver.is_format Max Reitz
@ 2020-05-13 11:05 ` Max Reitz
  2020-05-13 11:05 ` [PATCH v4 04/34] block: Add BdrvChildRole and BdrvChildRoleBits Max Reitz
                   ` (32 subsequent siblings)
  35 siblings, 0 replies; 54+ messages in thread
From: Max Reitz @ 2020-05-13 11:05 UTC (permalink / raw)
  To: qemu-block; +Cc: Kevin Wolf, qemu-devel, Max Reitz

This structure nearly only contains parent callbacks for child state
changes.  It cannot really reflect a child's role, because different
roles may overlap (as we will see when real roles are introduced), and
because parents can have custom callbacks even when the child fulfills a
standard role.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
---
 include/block/block.h       |   6 +-
 include/block/block_int.h   |  22 +++---
 block.c                     | 142 ++++++++++++++++++------------------
 block/backup-top.c          |   8 +-
 block/blkdebug.c            |   4 +-
 block/blklogwrites.c        |   8 +-
 block/block-backend.c       |   6 +-
 block/commit.c              |   2 +-
 block/copy-on-read.c        |   2 +-
 block/io.c                  |  22 +++---
 block/mirror.c              |   2 +-
 block/quorum.c              |   2 +-
 block/replication.c         |   2 +-
 block/vvfat.c               |   6 +-
 blockjob.c                  |   2 +-
 tests/test-bdrv-drain.c     |  36 ++++-----
 tests/test-bdrv-graph-mod.c |   2 +-
 17 files changed, 141 insertions(+), 133 deletions(-)

diff --git a/include/block/block.h b/include/block/block.h
index 8f3eb70df4..bc42e507bb 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -13,7 +13,7 @@
 /* block.c */
 typedef struct BlockDriver BlockDriver;
 typedef struct BdrvChild BdrvChild;
-typedef struct BdrvChildRole BdrvChildRole;
+typedef struct BdrvChildClass BdrvChildClass;
 
 typedef struct BlockDriverInfo {
     /* in bytes, 0 if irrelevant */
@@ -296,7 +296,7 @@ int bdrv_parse_discard_flags(const char *mode, int *flags);
 BdrvChild *bdrv_open_child(const char *filename,
                            QDict *options, const char *bdref_key,
                            BlockDriverState* parent,
-                           const BdrvChildRole *child_role,
+                           const BdrvChildClass *child_class,
                            bool allow_none, Error **errp);
 BlockDriverState *bdrv_open_blockdev_ref(BlockdevRef *ref, Error **errp);
 void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd,
@@ -541,7 +541,7 @@ void bdrv_unref_child(BlockDriverState *parent, BdrvChild *child);
 BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs,
                              BlockDriverState *child_bs,
                              const char *child_name,
-                             const BdrvChildRole *child_role,
+                             const BdrvChildClass *child_class,
                              Error **errp);
 
 bool bdrv_op_is_blocked(BlockDriverState *bs, BlockOpType op, Error **errp);
diff --git a/include/block/block_int.h b/include/block/block_int.h
index 1c24df53fd..9a78b981e4 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -556,14 +556,14 @@ struct BlockDriver {
      * the parents in @parent_perm and @parent_shared.
      *
      * If @c is NULL, return the permissions for attaching a new child for the
-     * given @role.
+     * given @child_class.
      *
      * If @reopen_queue is non-NULL, don't return the currently needed
      * permissions, but those that will be needed after applying the
      * @reopen_queue.
      */
      void (*bdrv_child_perm)(BlockDriverState *bs, BdrvChild *c,
-                             const BdrvChildRole *role,
+                             const BdrvChildClass *child_class,
                              BlockReopenQueue *reopen_queue,
                              uint64_t parent_perm, uint64_t parent_shared,
                              uint64_t *nperm, uint64_t *nshared);
@@ -665,7 +665,7 @@ typedef struct BdrvAioNotifier {
     QLIST_ENTRY(BdrvAioNotifier) list;
 } BdrvAioNotifier;
 
-struct BdrvChildRole {
+struct BdrvChildClass {
     /* If true, bdrv_replace_node() doesn't change the node this BdrvChild
      * points to. */
     bool stay_at_node;
@@ -738,14 +738,14 @@ struct BdrvChildRole {
     void (*set_aio_ctx)(BdrvChild *child, AioContext *ctx, GSList **ignore);
 };
 
-extern const BdrvChildRole child_file;
-extern const BdrvChildRole child_format;
-extern const BdrvChildRole child_backing;
+extern const BdrvChildClass child_file;
+extern const BdrvChildClass child_format;
+extern const BdrvChildClass child_backing;
 
 struct BdrvChild {
     BlockDriverState *bs;
     char *name;
-    const BdrvChildRole *role;
+    const BdrvChildClass *klass;
     void *opaque;
 
     /**
@@ -772,7 +772,7 @@ struct BdrvChild {
 
     /*
      * How many times the parent of this child has been drained
-     * (through role->drained_*).
+     * (through klass->drained_*).
      * Usually, this is equal to bs->quiesce_counter (potentially
      * reduced by bdrv_drain_all_count).  It may differ while the
      * child is entering or leaving a drained section.
@@ -1232,7 +1232,7 @@ BlockJob *backup_job_create(const char *job_id, BlockDriverState *bs,
 
 BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs,
                                   const char *child_name,
-                                  const BdrvChildRole *child_role,
+                                  const BdrvChildClass *child_class,
                                   AioContext *ctx,
                                   uint64_t perm, uint64_t shared_perm,
                                   void *opaque, Error **errp);
@@ -1263,7 +1263,7 @@ int bdrv_child_refresh_perms(BlockDriverState *bs, BdrvChild *c, Error **errp);
  * block filters: Forward CONSISTENT_READ, WRITE, WRITE_UNCHANGED and RESIZE to
  * all children */
 void bdrv_filter_default_perms(BlockDriverState *bs, BdrvChild *c,
-                               const BdrvChildRole *role,
+                               const BdrvChildClass *child_class,
                                BlockReopenQueue *reopen_queue,
                                uint64_t perm, uint64_t shared,
                                uint64_t *nperm, uint64_t *nshared);
@@ -1273,7 +1273,7 @@ void bdrv_filter_default_perms(BlockDriverState *bs, BdrvChild *c,
  * requires WRITE | RESIZE for read-write images, always requires
  * CONSISTENT_READ and doesn't share WRITE. */
 void bdrv_format_default_perms(BlockDriverState *bs, BdrvChild *c,
-                               const BdrvChildRole *role,
+                               const BdrvChildClass *child_class,
                                BlockReopenQueue *reopen_queue,
                                uint64_t perm, uint64_t shared,
                                uint64_t *nperm, uint64_t *nshared);
diff --git a/block.c b/block.c
index c6a5c144b7..0ce9b61c97 100644
--- a/block.c
+++ b/block.c
@@ -76,7 +76,7 @@ static BlockDriverState *bdrv_open_inherit(const char *filename,
                                            const char *reference,
                                            QDict *options, int flags,
                                            BlockDriverState *parent,
-                                           const BdrvChildRole *child_role,
+                                           const BdrvChildClass *child_class,
                                            Error **errp);
 
 /* If non-zero, use only whitelisted block drivers */
@@ -1183,7 +1183,7 @@ static void bdrv_inherited_options(int *child_flags, QDict *child_options,
     *child_flags = flags;
 }
 
-const BdrvChildRole child_file = {
+const BdrvChildClass child_file = {
     .parent_is_bds   = true,
     .get_parent_desc = bdrv_child_get_parent_desc,
     .inherit_options = bdrv_inherited_options,
@@ -1211,7 +1211,7 @@ static void bdrv_inherited_fmt_options(int *child_flags, QDict *child_options,
     *child_flags &= ~(BDRV_O_PROTOCOL | BDRV_O_NO_IO);
 }
 
-const BdrvChildRole child_format = {
+const BdrvChildClass child_format = {
     .parent_is_bds   = true,
     .get_parent_desc = bdrv_child_get_parent_desc,
     .inherit_options = bdrv_inherited_fmt_options,
@@ -1335,7 +1335,7 @@ static int bdrv_backing_update_filename(BdrvChild *c, BlockDriverState *base,
     return ret;
 }
 
-const BdrvChildRole child_backing = {
+const BdrvChildClass child_backing = {
     .parent_is_bds   = true,
     .get_parent_desc = bdrv_child_get_parent_desc,
     .attach          = bdrv_backing_attach,
@@ -1953,13 +1953,13 @@ bool bdrv_is_writable(BlockDriverState *bs)
 }
 
 static void bdrv_child_perm(BlockDriverState *bs, BlockDriverState *child_bs,
-                            BdrvChild *c, const BdrvChildRole *role,
+                            BdrvChild *c, const BdrvChildClass *child_class,
                             BlockReopenQueue *reopen_queue,
                             uint64_t parent_perm, uint64_t parent_shared,
                             uint64_t *nperm, uint64_t *nshared)
 {
     assert(bs->drv && bs->drv->bdrv_child_perm);
-    bs->drv->bdrv_child_perm(bs, c, role, reopen_queue,
+    bs->drv->bdrv_child_perm(bs, c, child_class, reopen_queue,
                              parent_perm, parent_shared,
                              nperm, nshared);
     /* TODO Take force_share from reopen_queue */
@@ -2053,7 +2053,7 @@ static int bdrv_check_perm(BlockDriverState *bs, BlockReopenQueue *q,
         uint64_t cur_perm, cur_shared;
         bool child_tighten_restr;
 
-        bdrv_child_perm(bs, c->bs, c, c->role, q,
+        bdrv_child_perm(bs, c->bs, c, c->klass, q,
                         cumulative_perms, cumulative_shared_perms,
                         &cur_perm, &cur_shared);
         ret = bdrv_child_check_perm(c, q, cur_perm, cur_shared, ignore_children,
@@ -2120,7 +2120,7 @@ static void bdrv_set_perm(BlockDriverState *bs, uint64_t cumulative_perms,
     /* Update all children */
     QLIST_FOREACH(c, &bs->children, next) {
         uint64_t cur_perm, cur_shared;
-        bdrv_child_perm(bs, c->bs, c, c->role, NULL,
+        bdrv_child_perm(bs, c->bs, c, c->klass, NULL,
                         cumulative_perms, cumulative_shared_perms,
                         &cur_perm, &cur_shared);
         bdrv_child_set_perm(c, cur_perm, cur_shared);
@@ -2145,8 +2145,8 @@ void bdrv_get_cumulative_perm(BlockDriverState *bs, uint64_t *perm,
 
 static char *bdrv_child_user_desc(BdrvChild *c)
 {
-    if (c->role->get_parent_desc) {
-        return c->role->get_parent_desc(c);
+    if (c->klass->get_parent_desc) {
+        return c->klass->get_parent_desc(c);
     }
 
     return g_strdup("another user");
@@ -2348,14 +2348,14 @@ int bdrv_child_refresh_perms(BlockDriverState *bs, BdrvChild *c, Error **errp)
     uint64_t perms, shared;
 
     bdrv_get_cumulative_perm(bs, &parent_perms, &parent_shared);
-    bdrv_child_perm(bs, c->bs, c, c->role, NULL, parent_perms, parent_shared,
+    bdrv_child_perm(bs, c->bs, c, c->klass, NULL, parent_perms, parent_shared,
                     &perms, &shared);
 
     return bdrv_child_try_set_perm(c, perms, shared, errp);
 }
 
 void bdrv_filter_default_perms(BlockDriverState *bs, BdrvChild *c,
-                               const BdrvChildRole *role,
+                               const BdrvChildClass *child_class,
                                BlockReopenQueue *reopen_queue,
                                uint64_t perm, uint64_t shared,
                                uint64_t *nperm, uint64_t *nshared)
@@ -2365,21 +2365,21 @@ void bdrv_filter_default_perms(BlockDriverState *bs, BdrvChild *c,
 }
 
 void bdrv_format_default_perms(BlockDriverState *bs, BdrvChild *c,
-                               const BdrvChildRole *role,
+                               const BdrvChildClass *child_class,
                                BlockReopenQueue *reopen_queue,
                                uint64_t perm, uint64_t shared,
                                uint64_t *nperm, uint64_t *nshared)
 {
-    bool backing = (role == &child_backing);
-    assert(role == &child_backing || role == &child_file);
+    bool backing = (child_class == &child_backing);
+    assert(child_class == &child_backing || child_class == &child_file);
 
     if (!backing) {
         int flags = bdrv_reopen_get_flags(reopen_queue, bs);
 
         /* Apart from the modifications below, the same permissions are
          * forwarded and left alone as for filters */
-        bdrv_filter_default_perms(bs, c, role, reopen_queue, perm, shared,
-                                  &perm, &shared);
+        bdrv_filter_default_perms(bs, c, child_class, reopen_queue,
+                                  perm, shared, &perm, &shared);
 
         /* Format drivers may touch metadata even if the guest doesn't write */
         if (bdrv_is_writable_after_reopen(bs, reopen_queue)) {
@@ -2456,7 +2456,7 @@ static void bdrv_replace_child_noperm(BdrvChild *child,
      * If the new child node is drained but the old one was not, flush
      * all outstanding requests to the old child node.
      */
-    while (drain_saldo > 0 && child->role->drained_begin) {
+    while (drain_saldo > 0 && child->klass->drained_begin) {
         bdrv_parent_drained_begin_single(child, true);
         drain_saldo--;
     }
@@ -2465,8 +2465,8 @@ static void bdrv_replace_child_noperm(BdrvChild *child,
         /* Detach first so that the recursive drain sections coming from @child
          * are already gone and we only end the drain sections that came from
          * elsewhere. */
-        if (child->role->detach) {
-            child->role->detach(child);
+        if (child->klass->detach) {
+            child->klass->detach(child);
         }
         QLIST_REMOVE(child, next_parent);
     }
@@ -2488,8 +2488,8 @@ static void bdrv_replace_child_noperm(BdrvChild *child,
         /* Attach only after starting new drained sections, so that recursive
          * drain sections coming from @child don't get an extra .drained_begin
          * callback. */
-        if (child->role->attach) {
-            child->role->attach(child);
+        if (child->klass->attach) {
+            child->klass->attach(child);
         }
     }
 
@@ -2497,7 +2497,7 @@ static void bdrv_replace_child_noperm(BdrvChild *child,
      * If the old child node was drained but the new one is not, allow
      * requests to come in only after the new node has been attached.
      */
-    while (drain_saldo < 0 && child->role->drained_end) {
+    while (drain_saldo < 0 && child->klass->drained_end) {
         bdrv_parent_drained_end_single(child);
         drain_saldo++;
     }
@@ -2570,7 +2570,7 @@ static void bdrv_replace_child(BdrvChild *child, BlockDriverState *new_bs)
  */
 BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs,
                                   const char *child_name,
-                                  const BdrvChildRole *child_role,
+                                  const BdrvChildClass *child_class,
                                   AioContext *ctx,
                                   uint64_t perm, uint64_t shared_perm,
                                   void *opaque, Error **errp)
@@ -2591,7 +2591,7 @@ BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs,
     *child = (BdrvChild) {
         .bs             = NULL,
         .name           = g_strdup(child_name),
-        .role           = child_role,
+        .klass          = child_class,
         .perm           = perm,
         .shared_perm    = shared_perm,
         .opaque         = opaque,
@@ -2602,15 +2602,15 @@ BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs,
      * try moving the parent into the AioContext of child_bs instead. */
     if (bdrv_get_aio_context(child_bs) != ctx) {
         ret = bdrv_try_set_aio_context(child_bs, ctx, &local_err);
-        if (ret < 0 && child_role->can_set_aio_ctx) {
+        if (ret < 0 && child_class->can_set_aio_ctx) {
             GSList *ignore = g_slist_prepend(NULL, child);
             ctx = bdrv_get_aio_context(child_bs);
-            if (child_role->can_set_aio_ctx(child, ctx, &ignore, NULL)) {
+            if (child_class->can_set_aio_ctx(child, ctx, &ignore, NULL)) {
                 error_free(local_err);
                 ret = 0;
                 g_slist_free(ignore);
                 ignore = g_slist_prepend(NULL, child);
-                child_role->set_aio_ctx(child, ctx, &ignore);
+                child_class->set_aio_ctx(child, ctx, &ignore);
             }
             g_slist_free(ignore);
         }
@@ -2643,7 +2643,7 @@ BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs,
 BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs,
                              BlockDriverState *child_bs,
                              const char *child_name,
-                             const BdrvChildRole *child_role,
+                             const BdrvChildClass *child_class,
                              Error **errp)
 {
     BdrvChild *child;
@@ -2652,10 +2652,10 @@ BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs,
     bdrv_get_cumulative_perm(parent_bs, &perm, &shared_perm);
 
     assert(parent_bs->drv);
-    bdrv_child_perm(parent_bs, child_bs, NULL, child_role, NULL,
+    bdrv_child_perm(parent_bs, child_bs, NULL, child_class, NULL,
                     perm, shared_perm, &perm, &shared_perm);
 
-    child = bdrv_root_attach_child(child_bs, child_name, child_role,
+    child = bdrv_root_attach_child(child_bs, child_name, child_class,
                                    bdrv_get_aio_context(parent_bs),
                                    perm, shared_perm, parent_bs, errp);
     if (child == NULL) {
@@ -2728,8 +2728,8 @@ static void bdrv_parent_cb_change_media(BlockDriverState *bs, bool load)
 {
     BdrvChild *c;
     QLIST_FOREACH(c, &bs->parents, next_parent) {
-        if (c->role->change_media) {
-            c->role->change_media(c, load);
+        if (c->klass->change_media) {
+            c->klass->change_media(c, load);
         }
     }
 }
@@ -2905,7 +2905,7 @@ free_exit:
 
 static BlockDriverState *
 bdrv_open_child_bs(const char *filename, QDict *options, const char *bdref_key,
-                   BlockDriverState *parent, const BdrvChildRole *child_role,
+                   BlockDriverState *parent, const BdrvChildClass *child_class,
                    bool allow_none, Error **errp)
 {
     BlockDriverState *bs = NULL;
@@ -2913,7 +2913,7 @@ bdrv_open_child_bs(const char *filename, QDict *options, const char *bdref_key,
     char *bdref_key_dot;
     const char *reference;
 
-    assert(child_role != NULL);
+    assert(child_class != NULL);
 
     bdref_key_dot = g_strdup_printf("%s.", bdref_key);
     qdict_extract_subqdict(options, &image_options, bdref_key_dot);
@@ -2937,7 +2937,7 @@ bdrv_open_child_bs(const char *filename, QDict *options, const char *bdref_key,
     }
 
     bs = bdrv_open_inherit(filename, reference, image_options, 0,
-                           parent, child_role, errp);
+                           parent, child_class, errp);
     if (!bs) {
         goto done;
     }
@@ -2964,22 +2964,24 @@ done:
 BdrvChild *bdrv_open_child(const char *filename,
                            QDict *options, const char *bdref_key,
                            BlockDriverState *parent,
-                           const BdrvChildRole *child_role,
+                           const BdrvChildClass *child_class,
                            bool allow_none, Error **errp)
 {
     BlockDriverState *bs;
 
-    bs = bdrv_open_child_bs(filename, options, bdref_key, parent, child_role,
+    bs = bdrv_open_child_bs(filename, options, bdref_key, parent, child_class,
                             allow_none, errp);
     if (bs == NULL) {
         return NULL;
     }
 
-    return bdrv_attach_child(parent, bs, bdref_key, child_role, errp);
+    return bdrv_attach_child(parent, bs, bdref_key, child_class, errp);
 }
 
-/* TODO Future callers may need to specify parent/child_role in order for
- * option inheritance to work. Existing callers use it for the root node. */
+/*
+ * TODO Future callers may need to specify parent/child_class in order for
+ * option inheritance to work. Existing callers use it for the root node.
+ */
 BlockDriverState *bdrv_open_blockdev_ref(BlockdevRef *ref, Error **errp)
 {
     BlockDriverState *bs = NULL;
@@ -3107,7 +3109,7 @@ static BlockDriverState *bdrv_open_inherit(const char *filename,
                                            const char *reference,
                                            QDict *options, int flags,
                                            BlockDriverState *parent,
-                                           const BdrvChildRole *child_role,
+                                           const BdrvChildClass *child_class,
                                            Error **errp)
 {
     int ret;
@@ -3121,8 +3123,8 @@ static BlockDriverState *bdrv_open_inherit(const char *filename,
     QDict *snapshot_options = NULL;
     int snapshot_flags = 0;
 
-    assert(!child_role || !flags);
-    assert(!child_role == !parent);
+    assert(!child_class || !flags);
+    assert(!child_class == !parent);
 
     if (reference) {
         bool options_non_empty = options ? qdict_size(options) : false;
@@ -3158,10 +3160,10 @@ static BlockDriverState *bdrv_open_inherit(const char *filename,
 
     bs->explicit_options = qdict_clone_shallow(options);
 
-    if (child_role) {
+    if (child_class) {
         bs->inherits_from = parent;
-        child_role->inherit_options(&flags, options,
-                                    parent->open_flags, parent->options);
+        child_class->inherit_options(&flags, options,
+                                     parent->open_flags, parent->options);
     }
 
     ret = bdrv_fill_options(&options, filename, &flags, &local_err);
@@ -3472,7 +3474,7 @@ static bool bdrv_recurse_has_child(BlockDriverState *bs,
 static BlockReopenQueue *bdrv_reopen_queue_child(BlockReopenQueue *bs_queue,
                                                  BlockDriverState *bs,
                                                  QDict *options,
-                                                 const BdrvChildRole *role,
+                                                 const BdrvChildClass *klass,
                                                  QDict *parent_options,
                                                  int parent_flags,
                                                  bool keep_old_opts)
@@ -3528,7 +3530,7 @@ static BlockReopenQueue *bdrv_reopen_queue_child(BlockReopenQueue *bs_queue,
     /* Inherit from parent node */
     if (parent_options) {
         flags = 0;
-        role->inherit_options(&flags, options, parent_flags, parent_options);
+        klass->inherit_options(&flags, options, parent_flags, parent_options);
     } else {
         flags = bdrv_get_flags(bs);
     }
@@ -3619,7 +3621,7 @@ static BlockReopenQueue *bdrv_reopen_queue_child(BlockReopenQueue *bs_queue,
         }
 
         bdrv_reopen_queue_child(bs_queue, child->bs, new_child_options,
-                                child->role, options, flags, child_keep_old);
+                                child->klass, options, flags, child_keep_old);
     }
 
     return bs_queue;
@@ -3799,7 +3801,7 @@ static void bdrv_reopen_perm(BlockReopenQueue *q, BlockDriverState *bs,
         } else {
             uint64_t nperm, nshared;
 
-            bdrv_child_perm(parent->state.bs, bs, c, c->role, q,
+            bdrv_child_perm(parent->state.bs, bs, c, c->klass, q,
                             parent->state.perm, parent->state.shared_perm,
                             &nperm, &nshared);
 
@@ -4305,7 +4307,7 @@ static bool should_update_child(BdrvChild *c, BlockDriverState *to)
     GHashTable *found;
     bool ret;
 
-    if (c->role->stay_at_node) {
+    if (c->klass->stay_at_node) {
         return false;
     }
 
@@ -4776,9 +4778,9 @@ int bdrv_drop_intermediate(BlockDriverState *top, BlockDriverState *base,
         }
 
         /* If so, update the backing file path in the image file */
-        if (c->role->update_filename) {
-            ret = c->role->update_filename(c, base, backing_file_str,
-                                           &local_err);
+        if (c->klass->update_filename) {
+            ret = c->klass->update_filename(c, base, backing_file_str,
+                                            &local_err);
             if (ret < 0) {
                 bdrv_abort_perm_update(base);
                 error_report_err(local_err);
@@ -5226,8 +5228,8 @@ const char *bdrv_get_parent_name(const BlockDriverState *bs)
 
     /* If multiple parents have a name, just pick the first one. */
     QLIST_FOREACH(c, &bs->parents, next_parent) {
-        if (c->role->get_name) {
-            name = c->role->get_name(c);
+        if (c->klass->get_name) {
+            name = c->klass->get_name(c);
             if (name && *name) {
                 return name;
             }
@@ -5586,8 +5588,8 @@ static void coroutine_fn bdrv_co_invalidate_cache(BlockDriverState *bs,
     }
 
     QLIST_FOREACH(parent, &bs->parents, next_parent) {
-        if (parent->role->activate) {
-            parent->role->activate(parent, &local_err);
+        if (parent->klass->activate) {
+            parent->klass->activate(parent, &local_err);
             if (local_err) {
                 bs->open_flags |= BDRV_O_INACTIVE;
                 error_propagate(errp, local_err);
@@ -5655,7 +5657,7 @@ static bool bdrv_has_bds_parent(BlockDriverState *bs, bool only_active)
     BdrvChild *parent;
 
     QLIST_FOREACH(parent, &bs->parents, next_parent) {
-        if (parent->role->parent_is_bds) {
+        if (parent->klass->parent_is_bds) {
             BlockDriverState *parent_bs = parent->opaque;
             if (!only_active || !(parent_bs->open_flags & BDRV_O_INACTIVE)) {
                 return true;
@@ -5694,8 +5696,8 @@ static int bdrv_inactivate_recurse(BlockDriverState *bs)
     }
 
     QLIST_FOREACH(parent, &bs->parents, next_parent) {
-        if (parent->role->inactivate) {
-            ret = parent->role->inactivate(parent);
+        if (parent->klass->inactivate) {
+            ret = parent->klass->inactivate(parent);
             if (ret < 0) {
                 return ret;
             }
@@ -6195,9 +6197,9 @@ void bdrv_set_aio_context_ignore(BlockDriverState *bs,
         if (g_slist_find(*ignore, child)) {
             continue;
         }
-        assert(child->role->set_aio_ctx);
+        assert(child->klass->set_aio_ctx);
         *ignore = g_slist_prepend(*ignore, child);
-        child->role->set_aio_ctx(child, new_context, ignore);
+        child->klass->set_aio_ctx(child, new_context, ignore);
     }
 
     bdrv_detach_aio_context(bs);
@@ -6237,15 +6239,17 @@ static bool bdrv_parent_can_set_aio_context(BdrvChild *c, AioContext *ctx,
     }
     *ignore = g_slist_prepend(*ignore, c);
 
-    /* A BdrvChildRole that doesn't handle AioContext changes cannot
-     * tolerate any AioContext changes */
-    if (!c->role->can_set_aio_ctx) {
+    /*
+     * A BdrvChildClass that doesn't handle AioContext changes cannot
+     * tolerate any AioContext changes
+     */
+    if (!c->klass->can_set_aio_ctx) {
         char *user = bdrv_child_user_desc(c);
         error_setg(errp, "Changing iothreads is not supported by %s", user);
         g_free(user);
         return false;
     }
-    if (!c->role->can_set_aio_ctx(c, ctx, ignore, errp)) {
+    if (!c->klass->can_set_aio_ctx(c, ctx, ignore, errp)) {
         assert(!errp || *errp);
         return false;
     }
@@ -6631,7 +6635,7 @@ void bdrv_refresh_filename(BlockDriverState *bs)
         drv->bdrv_gather_child_options(bs, opts, backing_overridden);
     } else {
         QLIST_FOREACH(child, &bs->children, next) {
-            if (child->role == &child_backing && !backing_overridden) {
+            if (child->klass == &child_backing && !backing_overridden) {
                 /* We can skip the backing BDS if it has not been overridden */
                 continue;
             }
diff --git a/block/backup-top.c b/block/backup-top.c
index 79b268e6dc..282845a410 100644
--- a/block/backup-top.c
+++ b/block/backup-top.c
@@ -122,7 +122,7 @@ static void backup_top_refresh_filename(BlockDriverState *bs)
 }
 
 static void backup_top_child_perm(BlockDriverState *bs, BdrvChild *c,
-                                  const BdrvChildRole *role,
+                                  const BdrvChildClass *child_class,
                                   BlockReopenQueue *reopen_queue,
                                   uint64_t perm, uint64_t shared,
                                   uint64_t *nperm, uint64_t *nshared)
@@ -142,7 +142,7 @@ static void backup_top_child_perm(BlockDriverState *bs, BdrvChild *c,
         return;
     }
 
-    if (role == &child_file) {
+    if (child_class == &child_file) {
         /*
          * Target child
          *
@@ -155,8 +155,8 @@ static void backup_top_child_perm(BlockDriverState *bs, BdrvChild *c,
         *nperm = BLK_PERM_WRITE;
     } else {
         /* Source child */
-        bdrv_filter_default_perms(bs, c, role, reopen_queue, perm, shared,
-                                  nperm, nshared);
+        bdrv_filter_default_perms(bs, c, child_class, reopen_queue,
+                                  perm, shared, nperm, nshared);
 
         if (perm & BLK_PERM_WRITE) {
             *nperm = *nperm | BLK_PERM_CONSISTENT_READ;
diff --git a/block/blkdebug.c b/block/blkdebug.c
index af44aa973f..f369d54ee4 100644
--- a/block/blkdebug.c
+++ b/block/blkdebug.c
@@ -993,14 +993,14 @@ static int blkdebug_reopen_prepare(BDRVReopenState *reopen_state,
 }
 
 static void blkdebug_child_perm(BlockDriverState *bs, BdrvChild *c,
-                                const BdrvChildRole *role,
+                                const BdrvChildClass *child_class,
                                 BlockReopenQueue *reopen_queue,
                                 uint64_t perm, uint64_t shared,
                                 uint64_t *nperm, uint64_t *nshared)
 {
     BDRVBlkdebugState *s = bs->opaque;
 
-    bdrv_filter_default_perms(bs, c, role, reopen_queue, perm, shared,
+    bdrv_filter_default_perms(bs, c, child_class, reopen_queue, perm, shared,
                               nperm, nshared);
 
     *nperm |= s->take_child_perms;
diff --git a/block/blklogwrites.c b/block/blklogwrites.c
index 04d8b33607..f3b3259d8d 100644
--- a/block/blklogwrites.c
+++ b/block/blklogwrites.c
@@ -282,7 +282,7 @@ static int64_t blk_log_writes_getlength(BlockDriverState *bs)
 }
 
 static void blk_log_writes_child_perm(BlockDriverState *bs, BdrvChild *c,
-                                      const BdrvChildRole *role,
+                                      const BdrvChildClass *child_class,
                                       BlockReopenQueue *ro_q,
                                       uint64_t perm, uint64_t shrd,
                                       uint64_t *nperm, uint64_t *nshrd)
@@ -294,9 +294,11 @@ static void blk_log_writes_child_perm(BlockDriverState *bs, BdrvChild *c,
     }
 
     if (!strcmp(c->name, "log")) {
-        bdrv_format_default_perms(bs, c, role, ro_q, perm, shrd, nperm, nshrd);
+        bdrv_format_default_perms(bs, c, child_class, ro_q, perm, shrd, nperm,
+                                  nshrd);
     } else {
-        bdrv_filter_default_perms(bs, c, role, ro_q, perm, shrd, nperm, nshrd);
+        bdrv_filter_default_perms(bs, c, child_class, ro_q, perm, shrd, nperm,
+                                  nshrd);
     }
 }
 
diff --git a/block/block-backend.c b/block/block-backend.c
index 47bd56244d..c0af79147a 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -297,7 +297,7 @@ static void blk_root_detach(BdrvChild *child)
     }
 }
 
-static const BdrvChildRole child_root = {
+static const BdrvChildClass child_root = {
     .inherit_options    = blk_root_inherit_options,
 
     .change_media       = blk_root_change_media,
@@ -716,7 +716,7 @@ static BlockBackend *bdrv_first_blk(BlockDriverState *bs)
 {
     BdrvChild *child;
     QLIST_FOREACH(child, &bs->parents, next_parent) {
-        if (child->role == &child_root) {
+        if (child->klass == &child_root) {
             return child->opaque;
         }
     }
@@ -740,7 +740,7 @@ bool bdrv_is_root_node(BlockDriverState *bs)
     BdrvChild *c;
 
     QLIST_FOREACH(c, &bs->parents, next_parent) {
-        if (c->role != &child_root) {
+        if (c->klass != &child_root) {
             return false;
         }
     }
diff --git a/block/commit.c b/block/commit.c
index b0a8a793cd..834eeae412 100644
--- a/block/commit.c
+++ b/block/commit.c
@@ -223,7 +223,7 @@ static void bdrv_commit_top_refresh_filename(BlockDriverState *bs)
 }
 
 static void bdrv_commit_top_child_perm(BlockDriverState *bs, BdrvChild *c,
-                                       const BdrvChildRole *role,
+                                       const BdrvChildClass *child_class,
                                        BlockReopenQueue *reopen_queue,
                                        uint64_t perm, uint64_t shared,
                                        uint64_t *nperm, uint64_t *nshared)
diff --git a/block/copy-on-read.c b/block/copy-on-read.c
index 242d3ff055..7504ca6ffc 100644
--- a/block/copy-on-read.c
+++ b/block/copy-on-read.c
@@ -51,7 +51,7 @@ static int cor_open(BlockDriverState *bs, QDict *options, int flags,
 #define PERM_UNCHANGED (BLK_PERM_ALL & ~PERM_PASSTHROUGH)
 
 static void cor_child_perm(BlockDriverState *bs, BdrvChild *c,
-                           const BdrvChildRole *role,
+                           const BdrvChildClass *child_class,
                            BlockReopenQueue *reopen_queue,
                            uint64_t perm, uint64_t shared,
                            uint64_t *nperm, uint64_t *nshared)
diff --git a/block/io.c b/block/io.c
index 7d30e61edc..121ce17a49 100644
--- a/block/io.c
+++ b/block/io.c
@@ -50,7 +50,7 @@ static void bdrv_parent_drained_begin(BlockDriverState *bs, BdrvChild *ignore,
     BdrvChild *c, *next;
 
     QLIST_FOREACH_SAFE(c, &bs->parents, next_parent, next) {
-        if (c == ignore || (ignore_bds_parents && c->role->parent_is_bds)) {
+        if (c == ignore || (ignore_bds_parents && c->klass->parent_is_bds)) {
             continue;
         }
         bdrv_parent_drained_begin_single(c, false);
@@ -62,8 +62,8 @@ static void bdrv_parent_drained_end_single_no_poll(BdrvChild *c,
 {
     assert(c->parent_quiesce_counter > 0);
     c->parent_quiesce_counter--;
-    if (c->role->drained_end) {
-        c->role->drained_end(c, drained_end_counter);
+    if (c->klass->drained_end) {
+        c->klass->drained_end(c, drained_end_counter);
     }
 }
 
@@ -81,7 +81,7 @@ static void bdrv_parent_drained_end(BlockDriverState *bs, BdrvChild *ignore,
     BdrvChild *c;
 
     QLIST_FOREACH(c, &bs->parents, next_parent) {
-        if (c == ignore || (ignore_bds_parents && c->role->parent_is_bds)) {
+        if (c == ignore || (ignore_bds_parents && c->klass->parent_is_bds)) {
             continue;
         }
         bdrv_parent_drained_end_single_no_poll(c, drained_end_counter);
@@ -90,8 +90,8 @@ static void bdrv_parent_drained_end(BlockDriverState *bs, BdrvChild *ignore,
 
 static bool bdrv_parent_drained_poll_single(BdrvChild *c)
 {
-    if (c->role->drained_poll) {
-        return c->role->drained_poll(c);
+    if (c->klass->drained_poll) {
+        return c->klass->drained_poll(c);
     }
     return false;
 }
@@ -103,7 +103,7 @@ static bool bdrv_parent_drained_poll(BlockDriverState *bs, BdrvChild *ignore,
     bool busy = false;
 
     QLIST_FOREACH_SAFE(c, &bs->parents, next_parent, next) {
-        if (c == ignore || (ignore_bds_parents && c->role->parent_is_bds)) {
+        if (c == ignore || (ignore_bds_parents && c->klass->parent_is_bds)) {
             continue;
         }
         busy |= bdrv_parent_drained_poll_single(c);
@@ -115,8 +115,8 @@ static bool bdrv_parent_drained_poll(BlockDriverState *bs, BdrvChild *ignore,
 void bdrv_parent_drained_begin_single(BdrvChild *c, bool poll)
 {
     c->parent_quiesce_counter++;
-    if (c->role->drained_begin) {
-        c->role->drained_begin(c);
+    if (c->klass->drained_begin) {
+        c->klass->drained_begin(c);
     }
     if (poll) {
         BDRV_POLL_WHILE(c->bs, bdrv_parent_drained_poll_single(c));
@@ -3326,8 +3326,8 @@ static void bdrv_parent_cb_resize(BlockDriverState *bs)
 {
     BdrvChild *c;
     QLIST_FOREACH(c, &bs->parents, next_parent) {
-        if (c->role->resize) {
-            c->role->resize(c);
+        if (c->klass->resize) {
+            c->klass->resize(c);
         }
     }
 }
diff --git a/block/mirror.c b/block/mirror.c
index 55e992670a..d6598463d5 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -1492,7 +1492,7 @@ static void bdrv_mirror_top_refresh_filename(BlockDriverState *bs)
 }
 
 static void bdrv_mirror_top_child_perm(BlockDriverState *bs, BdrvChild *c,
-                                       const BdrvChildRole *role,
+                                       const BdrvChildClass *child_class,
                                        BlockReopenQueue *reopen_queue,
                                        uint64_t perm, uint64_t shared,
                                        uint64_t *nperm, uint64_t *nshared)
diff --git a/block/quorum.c b/block/quorum.c
index 6d7a56bd93..a0824c300d 100644
--- a/block/quorum.c
+++ b/block/quorum.c
@@ -1151,7 +1151,7 @@ static char *quorum_dirname(BlockDriverState *bs, Error **errp)
 }
 
 static void quorum_child_perm(BlockDriverState *bs, BdrvChild *c,
-                              const BdrvChildRole *role,
+                              const BdrvChildClass *child_class,
                               BlockReopenQueue *reopen_queue,
                               uint64_t perm, uint64_t shared,
                               uint64_t *nperm, uint64_t *nshared)
diff --git a/block/replication.c b/block/replication.c
index 14b832154b..446bba2520 100644
--- a/block/replication.c
+++ b/block/replication.c
@@ -163,7 +163,7 @@ static void replication_close(BlockDriverState *bs)
 }
 
 static void replication_child_perm(BlockDriverState *bs, BdrvChild *c,
-                                   const BdrvChildRole *role,
+                                   const BdrvChildClass *child_class,
                                    BlockReopenQueue *reopen_queue,
                                    uint64_t perm, uint64_t shared,
                                    uint64_t *nperm, uint64_t *nshared)
diff --git a/block/vvfat.c b/block/vvfat.c
index 34c121c07a..f845d9b485 100644
--- a/block/vvfat.c
+++ b/block/vvfat.c
@@ -3136,7 +3136,7 @@ static void vvfat_qcow_options(int *child_flags, QDict *child_options,
     qdict_set_default_str(child_options, BDRV_OPT_CACHE_NO_FLUSH, "on");
 }
 
-static const BdrvChildRole child_vvfat_qcow = {
+static const BdrvChildClass child_vvfat_qcow = {
     .parent_is_bds      = true,
     .inherit_options    = vvfat_qcow_options,
 };
@@ -3210,14 +3210,14 @@ err:
 }
 
 static void vvfat_child_perm(BlockDriverState *bs, BdrvChild *c,
-                             const BdrvChildRole *role,
+                             const BdrvChildClass *child_class,
                              BlockReopenQueue *reopen_queue,
                              uint64_t perm, uint64_t shared,
                              uint64_t *nperm, uint64_t *nshared)
 {
     BDRVVVFATState *s = bs->opaque;
 
-    assert(c == s->qcow || role == &child_backing);
+    assert(c == s->qcow || child_class == &child_backing);
 
     if (c == s->qcow) {
         /* This is a private node, nobody should try to attach to it */
diff --git a/blockjob.c b/blockjob.c
index 2affa1844d..be38c8c550 100644
--- a/blockjob.c
+++ b/blockjob.c
@@ -163,7 +163,7 @@ static void child_job_set_aio_ctx(BdrvChild *c, AioContext *ctx,
     job->job.aio_context = ctx;
 }
 
-static const BdrvChildRole child_job = {
+static const BdrvChildClass child_job = {
     .get_parent_desc    = child_job_get_parent_desc,
     .drained_begin      = child_job_drained_begin,
     .drained_poll       = child_job_drained_poll,
diff --git a/tests/test-bdrv-drain.c b/tests/test-bdrv-drain.c
index fa0e6a648b..9d683a6c11 100644
--- a/tests/test-bdrv-drain.c
+++ b/tests/test-bdrv-drain.c
@@ -86,18 +86,20 @@ static int coroutine_fn bdrv_test_co_preadv(BlockDriverState *bs,
 }
 
 static void bdrv_test_child_perm(BlockDriverState *bs, BdrvChild *c,
-                                 const BdrvChildRole *role,
+                                 const BdrvChildClass *child_class,
                                  BlockReopenQueue *reopen_queue,
                                  uint64_t perm, uint64_t shared,
                                  uint64_t *nperm, uint64_t *nshared)
 {
-    /* bdrv_format_default_perms() accepts only these two, so disguise
-     * detach_by_driver_cb_role as one of them. */
-    if (role != &child_file && role != &child_backing) {
-        role = &child_file;
+    /*
+     * bdrv_format_default_perms() accepts only these two, so disguise
+     * detach_by_driver_cb_parent as one of them.
+     */
+    if (child_class != &child_file && child_class != &child_backing) {
+        child_class = &child_file;
     }
 
-    bdrv_format_default_perms(bs, c, role, reopen_queue, perm, shared,
+    bdrv_format_default_perms(bs, c, child_class, reopen_queue, perm, shared,
                               nperm, nshared);
 }
 
@@ -1332,7 +1334,7 @@ static void detach_by_driver_cb_drained_begin(BdrvChild *child)
     child_file.drained_begin(child);
 }
 
-static BdrvChildRole detach_by_driver_cb_role;
+static BdrvChildClass detach_by_driver_cb_class;
 
 /*
  * Initial graph:
@@ -1349,7 +1351,7 @@ static BdrvChildRole detach_by_driver_cb_role;
  *
  * by_parent_cb == false: Test that bdrv_drain_invoke() doesn't poll
  *
- *     PA's BdrvChildRole has a .drained_begin callback that schedules a BH
+ *     PA's BdrvChildClass has a .drained_begin callback that schedules a BH
  *     that does the same graph change. If bdrv_drain_invoke() calls it, the
  *     state is messed up, but if it is only polled in the single
  *     BDRV_POLL_WHILE() at the end of the drain, this should work fine.
@@ -1364,8 +1366,8 @@ static void test_detach_indirect(bool by_parent_cb)
     QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, NULL, 0);
 
     if (!by_parent_cb) {
-        detach_by_driver_cb_role = child_file;
-        detach_by_driver_cb_role.drained_begin =
+        detach_by_driver_cb_class = child_file;
+        detach_by_driver_cb_class.drained_begin =
             detach_by_driver_cb_drained_begin;
     }
 
@@ -1399,7 +1401,7 @@ static void test_detach_indirect(bool by_parent_cb)
 
     bdrv_ref(a);
     bdrv_attach_child(parent_a, a, "PA-A",
-                      by_parent_cb ? &child_file : &detach_by_driver_cb_role,
+                      by_parent_cb ? &child_file : &detach_by_driver_cb_class,
                       &error_abort);
 
     g_assert_cmpint(parent_a->refcnt, ==, 1);
@@ -1735,7 +1737,7 @@ static int drop_intermediate_poll_update_filename(BdrvChild *child,
 /**
  * Test a poll in the midst of bdrv_drop_intermediate().
  *
- * bdrv_drop_intermediate() calls BdrvChildRole.update_filename(),
+ * bdrv_drop_intermediate() calls BdrvChildClass.update_filename(),
  * which can yield or poll.  This may lead to graph changes, unless
  * the whole subtree in question is drained.
  *
@@ -1772,7 +1774,7 @@ static int drop_intermediate_poll_update_filename(BdrvChild *child,
  *
  * The solution is for bdrv_drop_intermediate() to drain top's
  * subtree.  This prevents graph changes from happening just because
- * BdrvChildRole.update_filename() yields or polls.  Thus, the block
+ * BdrvChildClass.update_filename() yields or polls.  Thus, the block
  * job is paused during that drained section and must finish before or
  * after.
  *
@@ -1780,7 +1782,7 @@ static int drop_intermediate_poll_update_filename(BdrvChild *child,
  */
 static void test_drop_intermediate_poll(void)
 {
-    static BdrvChildRole chain_child_role;
+    static BdrvChildClass chain_child_class;
     BlockDriverState *chain[3];
     TestSimpleBlockJob *job;
     BlockDriverState *job_node;
@@ -1788,8 +1790,8 @@ static void test_drop_intermediate_poll(void)
     int i;
     int ret;
 
-    chain_child_role = child_backing;
-    chain_child_role.update_filename = drop_intermediate_poll_update_filename;
+    chain_child_class = child_backing;
+    chain_child_class.update_filename = drop_intermediate_poll_update_filename;
 
     for (i = 0; i < 3; i++) {
         char name[32];
@@ -1810,7 +1812,7 @@ static void test_drop_intermediate_poll(void)
         if (i) {
             /* Takes the reference to chain[i - 1] */
             chain[i]->backing = bdrv_attach_child(chain[i], chain[i - 1],
-                                                  "chain", &chain_child_role,
+                                                  "chain", &chain_child_class,
                                                   &error_abort);
         }
     }
diff --git a/tests/test-bdrv-graph-mod.c b/tests/test-bdrv-graph-mod.c
index a007754d9e..fef42cb294 100644
--- a/tests/test-bdrv-graph-mod.c
+++ b/tests/test-bdrv-graph-mod.c
@@ -30,7 +30,7 @@ static BlockDriver bdrv_pass_through = {
 };
 
 static void no_perm_default_perms(BlockDriverState *bs, BdrvChild *c,
-                                         const BdrvChildRole *role,
+                                         const BdrvChildClass *child_class,
                                          BlockReopenQueue *reopen_queue,
                                          uint64_t perm, uint64_t shared,
                                          uint64_t *nperm, uint64_t *nshared)
-- 
2.26.2



^ permalink raw reply related	[flat|nested] 54+ messages in thread

* [PATCH v4 04/34] block: Add BdrvChildRole and BdrvChildRoleBits
  2020-05-13 11:05 [PATCH v4 00/34] block: Introduce real BdrvChildRole Max Reitz
                   ` (2 preceding siblings ...)
  2020-05-13 11:05 ` [PATCH v4 03/34] block: Rename BdrvChildRole to BdrvChildClass Max Reitz
@ 2020-05-13 11:05 ` Max Reitz
  2020-05-13 17:36   ` Eric Blake
  2020-05-13 11:05 ` [PATCH v4 05/34] block: Add BdrvChildRole to BdrvChild Max Reitz
                   ` (31 subsequent siblings)
  35 siblings, 1 reply; 54+ messages in thread
From: Max Reitz @ 2020-05-13 11:05 UTC (permalink / raw)
  To: qemu-block; +Cc: Kevin Wolf, qemu-devel, Max Reitz

This mask will supplement BdrvChildClass when it comes to what role (or
combination of roles) a child takes for its parent.  It consists of
BdrvChildRoleBits values (which is an enum).

Because empty enums are not allowed, let us just start with it filled.

Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 include/block/block.h | 56 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 56 insertions(+)

diff --git a/include/block/block.h b/include/block/block.h
index bc42e507bb..86cffa9ffd 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -268,6 +268,62 @@ enum {
     DEFAULT_PERM_UNCHANGED      = BLK_PERM_ALL & ~DEFAULT_PERM_PASSTHROUGH,
 };
 
+/*
+ * Flags parent nodes give for the child nodes to specify what kind of
+ * role(s) they take.
+ *
+ * At least one of DATA, METADATA, FILTERED, or COW must be set for
+ * every child.
+ */
+enum BdrvChildRoleBits {
+    /*
+     * This child stores data.
+     * Any node may have an arbitrary number of such children.
+     */
+    BDRV_CHILD_DATA         = (1 << 0),
+
+    /*
+     * This child stores metadata.
+     * Any node may have an arbitrary number of metadata-storing
+     * children.
+     */
+    BDRV_CHILD_METADATA     = (1 << 1),
+
+    /*
+     * A child that always presents exactly the same visible data as
+     * the parent, e.g. by virtue of the parent forwarding all reads
+     * and writes.
+     * This flag is mutually exclusive with DATA, METADATA, and COW.
+     * Any node may have at most one filtered child at a time.
+     */
+    BDRV_CHILD_FILTERED     = (1 << 2),
+
+    /*
+     * Child from which to read all data that isn’t allocated in the
+     * parent (i.e., the backing child); such data is copied to the
+     * parent through COW (and optionally COR).
+     * This field is mutually exclusive with DATA, METADATA, and
+     * FILTERED.
+     * Any node may have at most one such backing child at a time.
+     */
+    BDRV_CHILD_COW          = (1 << 3),
+
+    /*
+     * The primary child.  For most drivers, this is the child whose
+     * filename applies best to the parent node.
+     * Any node may have at most one primary child at a time.
+     */
+    BDRV_CHILD_PRIMARY      = (1 << 4),
+
+    /* Useful combination of flags */
+    BDRV_CHILD_IMAGE        = BDRV_CHILD_DATA
+                              | BDRV_CHILD_METADATA
+                              | BDRV_CHILD_PRIMARY,
+};
+
+/* Mask of BdrvChildRoleBits values */
+typedef unsigned int BdrvChildRole;
+
 char *bdrv_perm_names(uint64_t perm);
 uint64_t bdrv_qapi_perm_to_blk_perm(BlockPermission qapi_perm);
 
-- 
2.26.2



^ permalink raw reply related	[flat|nested] 54+ messages in thread

* [PATCH v4 05/34] block: Add BdrvChildRole to BdrvChild
  2020-05-13 11:05 [PATCH v4 00/34] block: Introduce real BdrvChildRole Max Reitz
                   ` (3 preceding siblings ...)
  2020-05-13 11:05 ` [PATCH v4 04/34] block: Add BdrvChildRole and BdrvChildRoleBits Max Reitz
@ 2020-05-13 11:05 ` Max Reitz
  2020-05-13 11:05 ` [PATCH v4 06/34] block: Pass BdrvChildRole to bdrv_child_perm() Max Reitz
                   ` (30 subsequent siblings)
  35 siblings, 0 replies; 54+ messages in thread
From: Max Reitz @ 2020-05-13 11:05 UTC (permalink / raw)
  To: qemu-block; +Cc: Kevin Wolf, qemu-devel, Max Reitz

For now, it is always set to 0.  Later patches in this series will
ensure that all callers pass an appropriate combination of flags.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
 include/block/block.h       |  2 ++
 include/block/block_int.h   |  2 ++
 block.c                     | 11 ++++++++---
 block/backup-top.c          |  3 ++-
 block/blkdebug.c            |  2 +-
 block/blklogwrites.c        |  6 +++---
 block/blkreplay.c           |  2 +-
 block/blkverify.c           |  4 ++--
 block/block-backend.c       |  4 ++--
 block/bochs.c               |  2 +-
 block/cloop.c               |  2 +-
 block/copy-on-read.c        |  2 +-
 block/crypto.c              |  2 +-
 block/dmg.c                 |  2 +-
 block/filter-compress.c     |  2 +-
 block/parallels.c           |  2 +-
 block/qcow.c                |  2 +-
 block/qcow2.c               |  6 +++---
 block/qed.c                 |  2 +-
 block/quorum.c              |  4 ++--
 block/raw-format.c          |  2 +-
 block/replication.c         |  2 +-
 block/throttle.c            |  2 +-
 block/vdi.c                 |  2 +-
 block/vhdx.c                |  2 +-
 block/vmdk.c                |  4 ++--
 block/vpc.c                 |  2 +-
 block/vvfat.c               |  2 +-
 blockjob.c                  |  5 +++--
 tests/test-bdrv-drain.c     | 20 +++++++++++---------
 tests/test-bdrv-graph-mod.c |  4 ++--
 31 files changed, 62 insertions(+), 49 deletions(-)

diff --git a/include/block/block.h b/include/block/block.h
index 86cffa9ffd..a5c1ddb4a1 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -353,6 +353,7 @@ BdrvChild *bdrv_open_child(const char *filename,
                            QDict *options, const char *bdref_key,
                            BlockDriverState* parent,
                            const BdrvChildClass *child_class,
+                           BdrvChildRole child_role,
                            bool allow_none, Error **errp);
 BlockDriverState *bdrv_open_blockdev_ref(BlockdevRef *ref, Error **errp);
 void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd,
@@ -598,6 +599,7 @@ BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs,
                              BlockDriverState *child_bs,
                              const char *child_name,
                              const BdrvChildClass *child_class,
+                             BdrvChildRole child_role,
                              Error **errp);
 
 bool bdrv_op_is_blocked(BlockDriverState *bs, BlockOpType op, Error **errp);
diff --git a/include/block/block_int.h b/include/block/block_int.h
index 9a78b981e4..1c6641c17a 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -746,6 +746,7 @@ struct BdrvChild {
     BlockDriverState *bs;
     char *name;
     const BdrvChildClass *klass;
+    BdrvChildRole role;
     void *opaque;
 
     /**
@@ -1233,6 +1234,7 @@ BlockJob *backup_job_create(const char *job_id, BlockDriverState *bs,
 BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs,
                                   const char *child_name,
                                   const BdrvChildClass *child_class,
+                                  BdrvChildRole child_role,
                                   AioContext *ctx,
                                   uint64_t perm, uint64_t shared_perm,
                                   void *opaque, Error **errp);
diff --git a/block.c b/block.c
index 0ce9b61c97..14810e0426 100644
--- a/block.c
+++ b/block.c
@@ -2571,6 +2571,7 @@ static void bdrv_replace_child(BdrvChild *child, BlockDriverState *new_bs)
 BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs,
                                   const char *child_name,
                                   const BdrvChildClass *child_class,
+                                  BdrvChildRole child_role,
                                   AioContext *ctx,
                                   uint64_t perm, uint64_t shared_perm,
                                   void *opaque, Error **errp)
@@ -2592,6 +2593,7 @@ BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs,
         .bs             = NULL,
         .name           = g_strdup(child_name),
         .klass          = child_class,
+        .role           = child_role,
         .perm           = perm,
         .shared_perm    = shared_perm,
         .opaque         = opaque,
@@ -2644,6 +2646,7 @@ BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs,
                              BlockDriverState *child_bs,
                              const char *child_name,
                              const BdrvChildClass *child_class,
+                             BdrvChildRole child_role,
                              Error **errp)
 {
     BdrvChild *child;
@@ -2656,7 +2659,7 @@ BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs,
                     perm, shared_perm, &perm, &shared_perm);
 
     child = bdrv_root_attach_child(child_bs, child_name, child_class,
-                                   bdrv_get_aio_context(parent_bs),
+                                   child_role, bdrv_get_aio_context(parent_bs),
                                    perm, shared_perm, parent_bs, errp);
     if (child == NULL) {
         return NULL;
@@ -2774,7 +2777,7 @@ void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd,
     }
 
     bs->backing = bdrv_attach_child(bs, backing_hd, "backing", &child_backing,
-                                    errp);
+                                    0, errp);
     /* If backing_hd was already part of bs's backing chain, and
      * inherits_from pointed recursively to bs then let's update it to
      * point directly to bs (else it will become NULL). */
@@ -2965,6 +2968,7 @@ BdrvChild *bdrv_open_child(const char *filename,
                            QDict *options, const char *bdref_key,
                            BlockDriverState *parent,
                            const BdrvChildClass *child_class,
+                           BdrvChildRole child_role,
                            bool allow_none, Error **errp)
 {
     BlockDriverState *bs;
@@ -2975,7 +2979,8 @@ BdrvChild *bdrv_open_child(const char *filename,
         return NULL;
     }
 
-    return bdrv_attach_child(parent, bs, bdref_key, child_class, errp);
+    return bdrv_attach_child(parent, bs, bdref_key, child_class, child_role,
+                             errp);
 }
 
 /*
diff --git a/block/backup-top.c b/block/backup-top.c
index 282845a410..f891dd7838 100644
--- a/block/backup-top.c
+++ b/block/backup-top.c
@@ -214,7 +214,8 @@ BlockDriverState *bdrv_backup_top_append(BlockDriverState *source,
              source->supported_zero_flags);
 
     bdrv_ref(target);
-    state->target = bdrv_attach_child(top, target, "target", &child_file, errp);
+    state->target = bdrv_attach_child(top, target, "target", &child_file, 0,
+                                      errp);
     if (!state->target) {
         bdrv_unref(target);
         bdrv_unref(top);
diff --git a/block/blkdebug.c b/block/blkdebug.c
index f369d54ee4..c91e78d5c8 100644
--- a/block/blkdebug.c
+++ b/block/blkdebug.c
@@ -497,7 +497,7 @@ static int blkdebug_open(BlockDriverState *bs, QDict *options, int flags,
 
     /* Open the image file */
     bs->file = bdrv_open_child(qemu_opt_get(opts, "x-image"), options, "image",
-                               bs, &child_file, false, &local_err);
+                               bs, &child_file, 0, false, &local_err);
     if (local_err) {
         ret = -EINVAL;
         error_propagate(errp, local_err);
diff --git a/block/blklogwrites.c b/block/blklogwrites.c
index f3b3259d8d..739db6dcf6 100644
--- a/block/blklogwrites.c
+++ b/block/blklogwrites.c
@@ -157,7 +157,7 @@ static int blk_log_writes_open(BlockDriverState *bs, QDict *options, int flags,
     }
 
     /* Open the file */
-    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, false,
+    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 0, false,
                                &local_err);
     if (local_err) {
         ret = -EINVAL;
@@ -166,8 +166,8 @@ static int blk_log_writes_open(BlockDriverState *bs, QDict *options, int flags,
     }
 
     /* Open the log file */
-    s->log_file = bdrv_open_child(NULL, options, "log", bs, &child_file, false,
-                                  &local_err);
+    s->log_file = bdrv_open_child(NULL, options, "log", bs, &child_file, 0,
+                                  false, &local_err);
     if (local_err) {
         ret = -EINVAL;
         error_propagate(errp, local_err);
diff --git a/block/blkreplay.c b/block/blkreplay.c
index 131c9e8477..9b2814fc58 100644
--- a/block/blkreplay.c
+++ b/block/blkreplay.c
@@ -28,7 +28,7 @@ static int blkreplay_open(BlockDriverState *bs, QDict *options, int flags,
 
     /* Open the image file */
     bs->file = bdrv_open_child(NULL, options, "image",
-                               bs, &child_file, false, &local_err);
+                               bs, &child_file, 0, false, &local_err);
     if (local_err) {
         ret = -EINVAL;
         error_propagate(errp, local_err);
diff --git a/block/blkverify.c b/block/blkverify.c
index ba6b1853ae..ba4f6d7b7c 100644
--- a/block/blkverify.c
+++ b/block/blkverify.c
@@ -125,7 +125,7 @@ static int blkverify_open(BlockDriverState *bs, QDict *options, int flags,
 
     /* Open the raw file */
     bs->file = bdrv_open_child(qemu_opt_get(opts, "x-raw"), options, "raw",
-                               bs, &child_file, false, &local_err);
+                               bs, &child_file, 0, false, &local_err);
     if (local_err) {
         ret = -EINVAL;
         error_propagate(errp, local_err);
@@ -134,7 +134,7 @@ static int blkverify_open(BlockDriverState *bs, QDict *options, int flags,
 
     /* Open the test file */
     s->test_file = bdrv_open_child(qemu_opt_get(opts, "x-image"), options,
-                                   "test", bs, &child_format, false,
+                                   "test", bs, &child_format, 0, false,
                                    &local_err);
     if (local_err) {
         ret = -EINVAL;
diff --git a/block/block-backend.c b/block/block-backend.c
index c0af79147a..efc7acb3d8 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -423,7 +423,7 @@ BlockBackend *blk_new_open(const char *filename, const char *reference,
         return NULL;
     }
 
-    blk->root = bdrv_root_attach_child(bs, "root", &child_root, blk->ctx,
+    blk->root = bdrv_root_attach_child(bs, "root", &child_root, 0, blk->ctx,
                                        perm, BLK_PERM_ALL, blk, errp);
     if (!blk->root) {
         blk_unref(blk);
@@ -834,7 +834,7 @@ int blk_insert_bs(BlockBackend *blk, BlockDriverState *bs, Error **errp)
 {
     ThrottleGroupMember *tgm = &blk->public.throttle_group_member;
     bdrv_ref(bs);
-    blk->root = bdrv_root_attach_child(bs, "root", &child_root, blk->ctx,
+    blk->root = bdrv_root_attach_child(bs, "root", &child_root, 0, blk->ctx,
                                        blk->perm, blk->shared_perm, blk, errp);
     if (blk->root == NULL) {
         return -EPERM;
diff --git a/block/bochs.c b/block/bochs.c
index e7bbeaa1c4..b013e73063 100644
--- a/block/bochs.c
+++ b/block/bochs.c
@@ -110,7 +110,7 @@ static int bochs_open(BlockDriverState *bs, QDict *options, int flags,
         return ret;
     }
 
-    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file,
+    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 0,
                                false, errp);
     if (!bs->file) {
         return -EINVAL;
diff --git a/block/cloop.c b/block/cloop.c
index f90f1a4b4c..3ed9fa63cc 100644
--- a/block/cloop.c
+++ b/block/cloop.c
@@ -71,7 +71,7 @@ static int cloop_open(BlockDriverState *bs, QDict *options, int flags,
         return ret;
     }
 
-    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file,
+    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 0,
                                false, errp);
     if (!bs->file) {
         return -EINVAL;
diff --git a/block/copy-on-read.c b/block/copy-on-read.c
index 7504ca6ffc..a2c4e6dc58 100644
--- a/block/copy-on-read.c
+++ b/block/copy-on-read.c
@@ -28,7 +28,7 @@
 static int cor_open(BlockDriverState *bs, QDict *options, int flags,
                     Error **errp)
 {
-    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, false,
+    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 0, false,
                                errp);
     if (!bs->file) {
         return -EINVAL;
diff --git a/block/crypto.c b/block/crypto.c
index bdb2b27475..8b516bfee2 100644
--- a/block/crypto.c
+++ b/block/crypto.c
@@ -218,7 +218,7 @@ static int block_crypto_open_generic(QCryptoBlockFormat format,
     unsigned int cflags = 0;
     QDict *cryptoopts = NULL;
 
-    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file,
+    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 0,
                                false, errp);
     if (!bs->file) {
         return -EINVAL;
diff --git a/block/dmg.c b/block/dmg.c
index ef3c6e771d..af8188638c 100644
--- a/block/dmg.c
+++ b/block/dmg.c
@@ -439,7 +439,7 @@ static int dmg_open(BlockDriverState *bs, QDict *options, int flags,
         return ret;
     }
 
-    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file,
+    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 0,
                                false, errp);
     if (!bs->file) {
         return -EINVAL;
diff --git a/block/filter-compress.c b/block/filter-compress.c
index 82c315b298..4dc5f9fb8c 100644
--- a/block/filter-compress.c
+++ b/block/filter-compress.c
@@ -30,7 +30,7 @@
 static int compress_open(BlockDriverState *bs, QDict *options, int flags,
                          Error **errp)
 {
-    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, false,
+    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 0, false,
                                errp);
     if (!bs->file) {
         return -EINVAL;
diff --git a/block/parallels.c b/block/parallels.c
index bd5f6ffa09..9855ac1162 100644
--- a/block/parallels.c
+++ b/block/parallels.c
@@ -739,7 +739,7 @@ static int parallels_open(BlockDriverState *bs, QDict *options, int flags,
     Error *local_err = NULL;
     char *buf;
 
-    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file,
+    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 0,
                                false, errp);
     if (!bs->file) {
         return -EINVAL;
diff --git a/block/qcow.c b/block/qcow.c
index 6a72dea049..13583f0339 100644
--- a/block/qcow.c
+++ b/block/qcow.c
@@ -130,7 +130,7 @@ static int qcow_open(BlockDriverState *bs, QDict *options, int flags,
     qdict_extract_subqdict(options, &encryptopts, "encrypt.");
     encryptfmt = qdict_get_try_str(encryptopts, "format");
 
-    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file,
+    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 0,
                                false, errp);
     if (!bs->file) {
         ret = -EINVAL;
diff --git a/block/qcow2.c b/block/qcow2.c
index 76bec61ee9..86335d9403 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -1591,7 +1591,7 @@ static int coroutine_fn qcow2_do_open(BlockDriverState *bs, QDict *options,
 
     /* Open external data file */
     s->data_file = bdrv_open_child(NULL, options, "data-file", bs, &child_file,
-                                   true, &local_err);
+                                   0, true, &local_err);
     if (local_err) {
         error_propagate(errp, local_err);
         ret = -EINVAL;
@@ -1601,7 +1601,7 @@ static int coroutine_fn qcow2_do_open(BlockDriverState *bs, QDict *options,
     if (s->incompatible_features & QCOW2_INCOMPAT_DATA_FILE) {
         if (!s->data_file && s->image_data_file) {
             s->data_file = bdrv_open_child(s->image_data_file, options,
-                                           "data-file", bs, &child_file,
+                                           "data-file", bs, &child_file, 0,
                                            false, errp);
             if (!s->data_file) {
                 ret = -EINVAL;
@@ -1863,7 +1863,7 @@ static int qcow2_open(BlockDriverState *bs, QDict *options, int flags,
         .ret = -EINPROGRESS
     };
 
-    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file,
+    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 0,
                                false, errp);
     if (!bs->file) {
         return -EINVAL;
diff --git a/block/qed.c b/block/qed.c
index 337eb6dbb6..1ad2aba810 100644
--- a/block/qed.c
+++ b/block/qed.c
@@ -547,7 +547,7 @@ static int bdrv_qed_open(BlockDriverState *bs, QDict *options, int flags,
         .ret = -EINPROGRESS
     };
 
-    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file,
+    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 0,
                                false, errp);
     if (!bs->file) {
         return -EINVAL;
diff --git a/block/quorum.c b/block/quorum.c
index a0824c300d..024de76e6f 100644
--- a/block/quorum.c
+++ b/block/quorum.c
@@ -977,7 +977,7 @@ static int quorum_open(BlockDriverState *bs, QDict *options, int flags,
         assert(ret < 32);
 
         s->children[i] = bdrv_open_child(NULL, options, indexstr, bs,
-                                         &child_format, false, &local_err);
+                                         &child_format, 0, false, &local_err);
         if (local_err) {
             ret = -EINVAL;
             goto close_exit;
@@ -1053,7 +1053,7 @@ static void quorum_add_child(BlockDriverState *bs, BlockDriverState *child_bs,
     /* We can safely add the child now */
     bdrv_ref(child_bs);
 
-    child = bdrv_attach_child(bs, child_bs, indexstr, &child_format, errp);
+    child = bdrv_attach_child(bs, child_bs, indexstr, &child_format, 0, errp);
     if (child == NULL) {
         s->next_child_index--;
         goto out;
diff --git a/block/raw-format.c b/block/raw-format.c
index 00e13bb41e..4b8d4ce8be 100644
--- a/block/raw-format.c
+++ b/block/raw-format.c
@@ -428,7 +428,7 @@ static int raw_open(BlockDriverState *bs, QDict *options, int flags,
     BDRVRawState *s = bs->opaque;
     int ret;
 
-    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file,
+    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 0,
                                false, errp);
     if (!bs->file) {
         return -EINVAL;
diff --git a/block/replication.c b/block/replication.c
index 446bba2520..9ee529cffb 100644
--- a/block/replication.c
+++ b/block/replication.c
@@ -90,7 +90,7 @@ static int replication_open(BlockDriverState *bs, QDict *options,
     const char *mode;
     const char *top_id;
 
-    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file,
+    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 0,
                                false, errp);
     if (!bs->file) {
         return -EINVAL;
diff --git a/block/throttle.c b/block/throttle.c
index 71f4bb0ad1..2dea913be7 100644
--- a/block/throttle.c
+++ b/block/throttle.c
@@ -82,7 +82,7 @@ static int throttle_open(BlockDriverState *bs, QDict *options,
     int ret;
 
     bs->file = bdrv_open_child(NULL, options, "file", bs,
-                               &child_file, false, errp);
+                               &child_file, 0, false, errp);
     if (!bs->file) {
         return -EINVAL;
     }
diff --git a/block/vdi.c b/block/vdi.c
index 0ef733ae19..653acb5fc1 100644
--- a/block/vdi.c
+++ b/block/vdi.c
@@ -378,7 +378,7 @@ static int vdi_open(BlockDriverState *bs, QDict *options, int flags,
     Error *local_err = NULL;
     QemuUUID uuid_link, uuid_parent;
 
-    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file,
+    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 0,
                                false, errp);
     if (!bs->file) {
         return -EINVAL;
diff --git a/block/vhdx.c b/block/vhdx.c
index e692cf80cc..dde156c97b 100644
--- a/block/vhdx.c
+++ b/block/vhdx.c
@@ -996,7 +996,7 @@ static int vhdx_open(BlockDriverState *bs, QDict *options, int flags,
     uint64_t signature;
     Error *local_err = NULL;
 
-    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file,
+    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 0,
                                false, errp);
     if (!bs->file) {
         return -EINVAL;
diff --git a/block/vmdk.c b/block/vmdk.c
index 56e85689f3..c2cb741e2d 100644
--- a/block/vmdk.c
+++ b/block/vmdk.c
@@ -1152,7 +1152,7 @@ static int vmdk_parse_extents(const char *desc, BlockDriverState *bs,
         assert(ret < 32);
 
         extent_file = bdrv_open_child(extent_path, options, extent_opt_prefix,
-                                      bs, &child_file, false, &local_err);
+                                      bs, &child_file, 0, false, &local_err);
         g_free(extent_path);
         if (local_err) {
             error_propagate(errp, local_err);
@@ -1257,7 +1257,7 @@ static int vmdk_open(BlockDriverState *bs, QDict *options, int flags,
     uint32_t magic;
     Error *local_err = NULL;
 
-    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file,
+    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 0,
                                false, errp);
     if (!bs->file) {
         return -EINVAL;
diff --git a/block/vpc.c b/block/vpc.c
index 46a2d48659..b2a86074a5 100644
--- a/block/vpc.c
+++ b/block/vpc.c
@@ -228,7 +228,7 @@ static int vpc_open(BlockDriverState *bs, QDict *options, int flags,
     int ret;
     int64_t bs_size;
 
-    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file,
+    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 0,
                                false, errp);
     if (!bs->file) {
         return -EINVAL;
diff --git a/block/vvfat.c b/block/vvfat.c
index f845d9b485..cd8ae50a2c 100644
--- a/block/vvfat.c
+++ b/block/vvfat.c
@@ -3183,7 +3183,7 @@ static int enable_write_target(BlockDriverState *bs, Error **errp)
     options = qdict_new();
     qdict_put_str(options, "write-target.driver", "qcow");
     s->qcow = bdrv_open_child(s->qcow_filename, options, "write-target", bs,
-                              &child_vvfat_qcow, false, errp);
+                              &child_vvfat_qcow, 0, false, errp);
     qobject_unref(options);
     if (!s->qcow) {
         ret = -EINVAL;
diff --git a/blockjob.c b/blockjob.c
index be38c8c550..470facfd47 100644
--- a/blockjob.c
+++ b/blockjob.c
@@ -217,8 +217,9 @@ int block_job_add_bdrv(BlockJob *job, const char *name, BlockDriverState *bs,
     if (job->job.aio_context != qemu_get_aio_context()) {
         aio_context_release(job->job.aio_context);
     }
-    c = bdrv_root_attach_child(bs, name, &child_job, job->job.aio_context,
-                               perm, shared_perm, job, errp);
+    c = bdrv_root_attach_child(bs, name, &child_job, 0,
+                               job->job.aio_context, perm, shared_perm, job,
+                               errp);
     if (job->job.aio_context != qemu_get_aio_context()) {
         aio_context_acquire(job->job.aio_context);
     }
diff --git a/tests/test-bdrv-drain.c b/tests/test-bdrv-drain.c
index 9d683a6c11..c03705ea37 100644
--- a/tests/test-bdrv-drain.c
+++ b/tests/test-bdrv-drain.c
@@ -1202,7 +1202,7 @@ static void do_test_delete_by_drain(bool detach_instead_of_delete,
 
     null_bs = bdrv_open("null-co://", NULL, NULL, BDRV_O_RDWR | BDRV_O_PROTOCOL,
                         &error_abort);
-    bdrv_attach_child(bs, null_bs, "null-child", &child_file, &error_abort);
+    bdrv_attach_child(bs, null_bs, "null-child", &child_file, 0, &error_abort);
 
     /* This child will be the one to pass to requests through to, and
      * it will stall until a drain occurs */
@@ -1211,13 +1211,13 @@ static void do_test_delete_by_drain(bool detach_instead_of_delete,
     child_bs->total_sectors = 65536 >> BDRV_SECTOR_BITS;
     /* Takes our reference to child_bs */
     tts->wait_child = bdrv_attach_child(bs, child_bs, "wait-child", &child_file,
-                                        &error_abort);
+                                        0, &error_abort);
 
     /* This child is just there to be deleted
      * (for detach_instead_of_delete == true) */
     null_bs = bdrv_open("null-co://", NULL, NULL, BDRV_O_RDWR | BDRV_O_PROTOCOL,
                         &error_abort);
-    bdrv_attach_child(bs, null_bs, "null-child", &child_file, &error_abort);
+    bdrv_attach_child(bs, null_bs, "null-child", &child_file, 0, &error_abort);
 
     blk = blk_new(qemu_get_aio_context(), BLK_PERM_ALL, BLK_PERM_ALL);
     blk_insert_bs(blk, bs, &error_abort);
@@ -1314,7 +1314,7 @@ static void detach_indirect_bh(void *opaque)
 
     bdrv_ref(data->c);
     data->child_c = bdrv_attach_child(data->parent_b, data->c, "PB-C",
-                                      &child_file, &error_abort);
+                                      &child_file, 0, &error_abort);
 }
 
 static void detach_by_parent_aio_cb(void *opaque, int ret)
@@ -1396,13 +1396,15 @@ static void test_detach_indirect(bool by_parent_cb)
     /* Set child relationships */
     bdrv_ref(b);
     bdrv_ref(a);
-    child_b = bdrv_attach_child(parent_b, b, "PB-B", &child_file, &error_abort);
-    child_a = bdrv_attach_child(parent_b, a, "PB-A", &child_backing, &error_abort);
+    child_b = bdrv_attach_child(parent_b, b, "PB-B", &child_file, 0,
+                                &error_abort);
+    child_a = bdrv_attach_child(parent_b, a, "PB-A", &child_backing, 0,
+                                &error_abort);
 
     bdrv_ref(a);
     bdrv_attach_child(parent_a, a, "PA-A",
                       by_parent_cb ? &child_file : &detach_by_driver_cb_class,
-                      &error_abort);
+                      0, &error_abort);
 
     g_assert_cmpint(parent_a->refcnt, ==, 1);
     g_assert_cmpint(parent_b->refcnt, ==, 1);
@@ -1813,7 +1815,7 @@ static void test_drop_intermediate_poll(void)
             /* Takes the reference to chain[i - 1] */
             chain[i]->backing = bdrv_attach_child(chain[i], chain[i - 1],
                                                   "chain", &chain_child_class,
-                                                  &error_abort);
+                                                  0, &error_abort);
         }
     }
 
@@ -2031,7 +2033,7 @@ static void do_test_replace_child_mid_drain(int old_drain_count,
 
     bdrv_ref(old_child_bs);
     parent_bs->backing = bdrv_attach_child(parent_bs, old_child_bs, "child",
-                                           &child_backing, &error_abort);
+                                           &child_backing, 0, &error_abort);
 
     for (i = 0; i < old_drain_count; i++) {
         bdrv_drained_begin(old_child_bs);
diff --git a/tests/test-bdrv-graph-mod.c b/tests/test-bdrv-graph-mod.c
index fef42cb294..8b8c186c9f 100644
--- a/tests/test-bdrv-graph-mod.c
+++ b/tests/test-bdrv-graph-mod.c
@@ -111,7 +111,7 @@ static void test_update_perm_tree(void)
 
     blk_insert_bs(root, bs, &error_abort);
 
-    bdrv_attach_child(filter, bs, "child", &child_file, &error_abort);
+    bdrv_attach_child(filter, bs, "child", &child_file, 0, &error_abort);
 
     bdrv_append(filter, bs, &local_err);
 
@@ -177,7 +177,7 @@ static void test_should_update_child(void)
     bdrv_set_backing_hd(target, bs, &error_abort);
 
     g_assert(target->backing->bs == bs);
-    bdrv_attach_child(filter, target, "target", &child_file, &error_abort);
+    bdrv_attach_child(filter, target, "target", &child_file, 0, &error_abort);
     bdrv_append(filter, bs, &error_abort);
     g_assert(target->backing->bs == bs);
 
-- 
2.26.2



^ permalink raw reply related	[flat|nested] 54+ messages in thread

* [PATCH v4 06/34] block: Pass BdrvChildRole to bdrv_child_perm()
  2020-05-13 11:05 [PATCH v4 00/34] block: Introduce real BdrvChildRole Max Reitz
                   ` (4 preceding siblings ...)
  2020-05-13 11:05 ` [PATCH v4 05/34] block: Add BdrvChildRole to BdrvChild Max Reitz
@ 2020-05-13 11:05 ` Max Reitz
  2020-05-13 11:05 ` [PATCH v4 07/34] block: Pass BdrvChildRole to .inherit_options() Max Reitz
                   ` (29 subsequent siblings)
  35 siblings, 0 replies; 54+ messages in thread
From: Max Reitz @ 2020-05-13 11:05 UTC (permalink / raw)
  To: qemu-block; +Cc: Kevin Wolf, qemu-devel, Max Reitz

For now, all callers pass 0 and no callee evaluates this value.  Later
patches will change both.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
 include/block/block_int.h   |  5 ++++-
 block.c                     | 22 ++++++++++++----------
 block/backup-top.c          |  3 ++-
 block/blkdebug.c            |  5 +++--
 block/blklogwrites.c        |  9 +++++----
 block/commit.c              |  1 +
 block/copy-on-read.c        |  1 +
 block/mirror.c              |  1 +
 block/quorum.c              |  1 +
 block/replication.c         |  1 +
 block/vvfat.c               |  1 +
 tests/test-bdrv-drain.c     |  5 +++--
 tests/test-bdrv-graph-mod.c |  1 +
 13 files changed, 36 insertions(+), 20 deletions(-)

diff --git a/include/block/block_int.h b/include/block/block_int.h
index 1c6641c17a..dc4bc486d6 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -556,7 +556,7 @@ struct BlockDriver {
      * the parents in @parent_perm and @parent_shared.
      *
      * If @c is NULL, return the permissions for attaching a new child for the
-     * given @child_class.
+     * given @child_class and @role.
      *
      * If @reopen_queue is non-NULL, don't return the currently needed
      * permissions, but those that will be needed after applying the
@@ -564,6 +564,7 @@ struct BlockDriver {
      */
      void (*bdrv_child_perm)(BlockDriverState *bs, BdrvChild *c,
                              const BdrvChildClass *child_class,
+                             BdrvChildRole role,
                              BlockReopenQueue *reopen_queue,
                              uint64_t parent_perm, uint64_t parent_shared,
                              uint64_t *nperm, uint64_t *nshared);
@@ -1266,6 +1267,7 @@ int bdrv_child_refresh_perms(BlockDriverState *bs, BdrvChild *c, Error **errp);
  * all children */
 void bdrv_filter_default_perms(BlockDriverState *bs, BdrvChild *c,
                                const BdrvChildClass *child_class,
+                               BdrvChildRole child_role,
                                BlockReopenQueue *reopen_queue,
                                uint64_t perm, uint64_t shared,
                                uint64_t *nperm, uint64_t *nshared);
@@ -1276,6 +1278,7 @@ void bdrv_filter_default_perms(BlockDriverState *bs, BdrvChild *c,
  * CONSISTENT_READ and doesn't share WRITE. */
 void bdrv_format_default_perms(BlockDriverState *bs, BdrvChild *c,
                                const BdrvChildClass *child_class,
+                               BdrvChildRole child_role,
                                BlockReopenQueue *reopen_queue,
                                uint64_t perm, uint64_t shared,
                                uint64_t *nperm, uint64_t *nshared);
diff --git a/block.c b/block.c
index 14810e0426..5d9a331f5b 100644
--- a/block.c
+++ b/block.c
@@ -1954,12 +1954,12 @@ bool bdrv_is_writable(BlockDriverState *bs)
 
 static void bdrv_child_perm(BlockDriverState *bs, BlockDriverState *child_bs,
                             BdrvChild *c, const BdrvChildClass *child_class,
-                            BlockReopenQueue *reopen_queue,
+                            BdrvChildRole role, BlockReopenQueue *reopen_queue,
                             uint64_t parent_perm, uint64_t parent_shared,
                             uint64_t *nperm, uint64_t *nshared)
 {
     assert(bs->drv && bs->drv->bdrv_child_perm);
-    bs->drv->bdrv_child_perm(bs, c, child_class, reopen_queue,
+    bs->drv->bdrv_child_perm(bs, c, child_class, role, reopen_queue,
                              parent_perm, parent_shared,
                              nperm, nshared);
     /* TODO Take force_share from reopen_queue */
@@ -2053,7 +2053,7 @@ static int bdrv_check_perm(BlockDriverState *bs, BlockReopenQueue *q,
         uint64_t cur_perm, cur_shared;
         bool child_tighten_restr;
 
-        bdrv_child_perm(bs, c->bs, c, c->klass, q,
+        bdrv_child_perm(bs, c->bs, c, c->klass, c->role, q,
                         cumulative_perms, cumulative_shared_perms,
                         &cur_perm, &cur_shared);
         ret = bdrv_child_check_perm(c, q, cur_perm, cur_shared, ignore_children,
@@ -2120,7 +2120,7 @@ static void bdrv_set_perm(BlockDriverState *bs, uint64_t cumulative_perms,
     /* Update all children */
     QLIST_FOREACH(c, &bs->children, next) {
         uint64_t cur_perm, cur_shared;
-        bdrv_child_perm(bs, c->bs, c, c->klass, NULL,
+        bdrv_child_perm(bs, c->bs, c, c->klass, c->role, NULL,
                         cumulative_perms, cumulative_shared_perms,
                         &cur_perm, &cur_shared);
         bdrv_child_set_perm(c, cur_perm, cur_shared);
@@ -2348,14 +2348,15 @@ int bdrv_child_refresh_perms(BlockDriverState *bs, BdrvChild *c, Error **errp)
     uint64_t perms, shared;
 
     bdrv_get_cumulative_perm(bs, &parent_perms, &parent_shared);
-    bdrv_child_perm(bs, c->bs, c, c->klass, NULL, parent_perms, parent_shared,
-                    &perms, &shared);
+    bdrv_child_perm(bs, c->bs, c, c->klass, c->role, NULL,
+                    parent_perms, parent_shared, &perms, &shared);
 
     return bdrv_child_try_set_perm(c, perms, shared, errp);
 }
 
 void bdrv_filter_default_perms(BlockDriverState *bs, BdrvChild *c,
                                const BdrvChildClass *child_class,
+                               BdrvChildRole role,
                                BlockReopenQueue *reopen_queue,
                                uint64_t perm, uint64_t shared,
                                uint64_t *nperm, uint64_t *nshared)
@@ -2366,6 +2367,7 @@ void bdrv_filter_default_perms(BlockDriverState *bs, BdrvChild *c,
 
 void bdrv_format_default_perms(BlockDriverState *bs, BdrvChild *c,
                                const BdrvChildClass *child_class,
+                               BdrvChildRole role,
                                BlockReopenQueue *reopen_queue,
                                uint64_t perm, uint64_t shared,
                                uint64_t *nperm, uint64_t *nshared)
@@ -2378,7 +2380,7 @@ void bdrv_format_default_perms(BlockDriverState *bs, BdrvChild *c,
 
         /* Apart from the modifications below, the same permissions are
          * forwarded and left alone as for filters */
-        bdrv_filter_default_perms(bs, c, child_class, reopen_queue,
+        bdrv_filter_default_perms(bs, c, child_class, role, reopen_queue,
                                   perm, shared, &perm, &shared);
 
         /* Format drivers may touch metadata even if the guest doesn't write */
@@ -2655,7 +2657,7 @@ BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs,
     bdrv_get_cumulative_perm(parent_bs, &perm, &shared_perm);
 
     assert(parent_bs->drv);
-    bdrv_child_perm(parent_bs, child_bs, NULL, child_class, NULL,
+    bdrv_child_perm(parent_bs, child_bs, NULL, child_class, child_role, NULL,
                     perm, shared_perm, &perm, &shared_perm);
 
     child = bdrv_root_attach_child(child_bs, child_name, child_class,
@@ -3683,7 +3685,7 @@ int bdrv_reopen_multiple(BlockReopenQueue *bs_queue, Error **errp)
         if (state->replace_backing_bs && state->new_backing_bs) {
             uint64_t nperm, nshared;
             bdrv_child_perm(state->bs, state->new_backing_bs,
-                            NULL, &child_backing, bs_queue,
+                            NULL, &child_backing, 0, bs_queue,
                             state->perm, state->shared_perm,
                             &nperm, &nshared);
             ret = bdrv_check_update_perm(state->new_backing_bs, NULL,
@@ -3806,7 +3808,7 @@ static void bdrv_reopen_perm(BlockReopenQueue *q, BlockDriverState *bs,
         } else {
             uint64_t nperm, nshared;
 
-            bdrv_child_perm(parent->state.bs, bs, c, c->klass, q,
+            bdrv_child_perm(parent->state.bs, bs, c, c->klass, c->role, q,
                             parent->state.perm, parent->state.shared_perm,
                             &nperm, &nshared);
 
diff --git a/block/backup-top.c b/block/backup-top.c
index f891dd7838..e2b4d2acd3 100644
--- a/block/backup-top.c
+++ b/block/backup-top.c
@@ -123,6 +123,7 @@ static void backup_top_refresh_filename(BlockDriverState *bs)
 
 static void backup_top_child_perm(BlockDriverState *bs, BdrvChild *c,
                                   const BdrvChildClass *child_class,
+                                  BdrvChildRole role,
                                   BlockReopenQueue *reopen_queue,
                                   uint64_t perm, uint64_t shared,
                                   uint64_t *nperm, uint64_t *nshared)
@@ -155,7 +156,7 @@ static void backup_top_child_perm(BlockDriverState *bs, BdrvChild *c,
         *nperm = BLK_PERM_WRITE;
     } else {
         /* Source child */
-        bdrv_filter_default_perms(bs, c, child_class, reopen_queue,
+        bdrv_filter_default_perms(bs, c, child_class, role, reopen_queue,
                                   perm, shared, nperm, nshared);
 
         if (perm & BLK_PERM_WRITE) {
diff --git a/block/blkdebug.c b/block/blkdebug.c
index c91e78d5c8..8dd8ed6055 100644
--- a/block/blkdebug.c
+++ b/block/blkdebug.c
@@ -994,14 +994,15 @@ static int blkdebug_reopen_prepare(BDRVReopenState *reopen_state,
 
 static void blkdebug_child_perm(BlockDriverState *bs, BdrvChild *c,
                                 const BdrvChildClass *child_class,
+                                BdrvChildRole role,
                                 BlockReopenQueue *reopen_queue,
                                 uint64_t perm, uint64_t shared,
                                 uint64_t *nperm, uint64_t *nshared)
 {
     BDRVBlkdebugState *s = bs->opaque;
 
-    bdrv_filter_default_perms(bs, c, child_class, reopen_queue, perm, shared,
-                              nperm, nshared);
+    bdrv_filter_default_perms(bs, c, child_class, role, reopen_queue,
+                              perm, shared, nperm, nshared);
 
     *nperm |= s->take_child_perms;
     *nshared &= ~s->unshare_child_perms;
diff --git a/block/blklogwrites.c b/block/blklogwrites.c
index 739db6dcf6..4faf912ef1 100644
--- a/block/blklogwrites.c
+++ b/block/blklogwrites.c
@@ -283,6 +283,7 @@ static int64_t blk_log_writes_getlength(BlockDriverState *bs)
 
 static void blk_log_writes_child_perm(BlockDriverState *bs, BdrvChild *c,
                                       const BdrvChildClass *child_class,
+                                      BdrvChildRole role,
                                       BlockReopenQueue *ro_q,
                                       uint64_t perm, uint64_t shrd,
                                       uint64_t *nperm, uint64_t *nshrd)
@@ -294,11 +295,11 @@ static void blk_log_writes_child_perm(BlockDriverState *bs, BdrvChild *c,
     }
 
     if (!strcmp(c->name, "log")) {
-        bdrv_format_default_perms(bs, c, child_class, ro_q, perm, shrd, nperm,
-                                  nshrd);
+        bdrv_format_default_perms(bs, c, child_class, role, ro_q, perm, shrd,
+                                  nperm, nshrd);
     } else {
-        bdrv_filter_default_perms(bs, c, child_class, ro_q, perm, shrd, nperm,
-                                  nshrd);
+        bdrv_filter_default_perms(bs, c, child_class, role, ro_q, perm, shrd,
+                                  nperm, nshrd);
     }
 }
 
diff --git a/block/commit.c b/block/commit.c
index 834eeae412..6af1c808bc 100644
--- a/block/commit.c
+++ b/block/commit.c
@@ -224,6 +224,7 @@ static void bdrv_commit_top_refresh_filename(BlockDriverState *bs)
 
 static void bdrv_commit_top_child_perm(BlockDriverState *bs, BdrvChild *c,
                                        const BdrvChildClass *child_class,
+                                       BdrvChildRole role,
                                        BlockReopenQueue *reopen_queue,
                                        uint64_t perm, uint64_t shared,
                                        uint64_t *nperm, uint64_t *nshared)
diff --git a/block/copy-on-read.c b/block/copy-on-read.c
index a2c4e6dc58..a2d92ac394 100644
--- a/block/copy-on-read.c
+++ b/block/copy-on-read.c
@@ -52,6 +52,7 @@ static int cor_open(BlockDriverState *bs, QDict *options, int flags,
 
 static void cor_child_perm(BlockDriverState *bs, BdrvChild *c,
                            const BdrvChildClass *child_class,
+                           BdrvChildRole role,
                            BlockReopenQueue *reopen_queue,
                            uint64_t perm, uint64_t shared,
                            uint64_t *nperm, uint64_t *nshared)
diff --git a/block/mirror.c b/block/mirror.c
index d6598463d5..cb4bdad32a 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -1493,6 +1493,7 @@ static void bdrv_mirror_top_refresh_filename(BlockDriverState *bs)
 
 static void bdrv_mirror_top_child_perm(BlockDriverState *bs, BdrvChild *c,
                                        const BdrvChildClass *child_class,
+                                       BdrvChildRole role,
                                        BlockReopenQueue *reopen_queue,
                                        uint64_t perm, uint64_t shared,
                                        uint64_t *nperm, uint64_t *nshared)
diff --git a/block/quorum.c b/block/quorum.c
index 024de76e6f..d37b77a522 100644
--- a/block/quorum.c
+++ b/block/quorum.c
@@ -1152,6 +1152,7 @@ static char *quorum_dirname(BlockDriverState *bs, Error **errp)
 
 static void quorum_child_perm(BlockDriverState *bs, BdrvChild *c,
                               const BdrvChildClass *child_class,
+                              BdrvChildRole role,
                               BlockReopenQueue *reopen_queue,
                               uint64_t perm, uint64_t shared,
                               uint64_t *nperm, uint64_t *nshared)
diff --git a/block/replication.c b/block/replication.c
index 9ee529cffb..61119ed36c 100644
--- a/block/replication.c
+++ b/block/replication.c
@@ -164,6 +164,7 @@ static void replication_close(BlockDriverState *bs)
 
 static void replication_child_perm(BlockDriverState *bs, BdrvChild *c,
                                    const BdrvChildClass *child_class,
+                                   BdrvChildRole role,
                                    BlockReopenQueue *reopen_queue,
                                    uint64_t perm, uint64_t shared,
                                    uint64_t *nperm, uint64_t *nshared)
diff --git a/block/vvfat.c b/block/vvfat.c
index cd8ae50a2c..6cf3c74fe3 100644
--- a/block/vvfat.c
+++ b/block/vvfat.c
@@ -3211,6 +3211,7 @@ err:
 
 static void vvfat_child_perm(BlockDriverState *bs, BdrvChild *c,
                              const BdrvChildClass *child_class,
+                             BdrvChildRole role,
                              BlockReopenQueue *reopen_queue,
                              uint64_t perm, uint64_t shared,
                              uint64_t *nperm, uint64_t *nshared)
diff --git a/tests/test-bdrv-drain.c b/tests/test-bdrv-drain.c
index c03705ea37..b3d7960bd0 100644
--- a/tests/test-bdrv-drain.c
+++ b/tests/test-bdrv-drain.c
@@ -87,6 +87,7 @@ static int coroutine_fn bdrv_test_co_preadv(BlockDriverState *bs,
 
 static void bdrv_test_child_perm(BlockDriverState *bs, BdrvChild *c,
                                  const BdrvChildClass *child_class,
+                                 BdrvChildRole role,
                                  BlockReopenQueue *reopen_queue,
                                  uint64_t perm, uint64_t shared,
                                  uint64_t *nperm, uint64_t *nshared)
@@ -99,8 +100,8 @@ static void bdrv_test_child_perm(BlockDriverState *bs, BdrvChild *c,
         child_class = &child_file;
     }
 
-    bdrv_format_default_perms(bs, c, child_class, reopen_queue, perm, shared,
-                              nperm, nshared);
+    bdrv_format_default_perms(bs, c, child_class, role, reopen_queue,
+                              perm, shared, nperm, nshared);
 }
 
 static int bdrv_test_change_backing_file(BlockDriverState *bs,
diff --git a/tests/test-bdrv-graph-mod.c b/tests/test-bdrv-graph-mod.c
index 8b8c186c9f..3707e2533c 100644
--- a/tests/test-bdrv-graph-mod.c
+++ b/tests/test-bdrv-graph-mod.c
@@ -31,6 +31,7 @@ static BlockDriver bdrv_pass_through = {
 
 static void no_perm_default_perms(BlockDriverState *bs, BdrvChild *c,
                                          const BdrvChildClass *child_class,
+                                         BdrvChildRole role,
                                          BlockReopenQueue *reopen_queue,
                                          uint64_t perm, uint64_t shared,
                                          uint64_t *nperm, uint64_t *nshared)
-- 
2.26.2



^ permalink raw reply related	[flat|nested] 54+ messages in thread

* [PATCH v4 07/34] block: Pass BdrvChildRole to .inherit_options()
  2020-05-13 11:05 [PATCH v4 00/34] block: Introduce real BdrvChildRole Max Reitz
                   ` (5 preceding siblings ...)
  2020-05-13 11:05 ` [PATCH v4 06/34] block: Pass BdrvChildRole to bdrv_child_perm() Max Reitz
@ 2020-05-13 11:05 ` Max Reitz
  2020-05-13 11:05 ` [PATCH v4 08/34] block: Pass parent_is_format " Max Reitz
                   ` (28 subsequent siblings)
  35 siblings, 0 replies; 54+ messages in thread
From: Max Reitz @ 2020-05-13 11:05 UTC (permalink / raw)
  To: qemu-block; +Cc: Kevin Wolf, qemu-devel, Max Reitz

For now, all callers (effectively) pass 0 and no callee evaluates thie
value.  Later patches will change both.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
 include/block/block_int.h |  3 ++-
 block.c                   | 40 +++++++++++++++++++++++----------------
 block/block-backend.c     |  3 ++-
 block/vvfat.c             |  3 ++-
 4 files changed, 30 insertions(+), 19 deletions(-)

diff --git a/include/block/block_int.h b/include/block/block_int.h
index dc4bc486d6..8c1160a577 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -677,7 +677,8 @@ struct BdrvChildClass {
      * non-BDS parents. */
     bool parent_is_bds;
 
-    void (*inherit_options)(int *child_flags, QDict *child_options,
+    void (*inherit_options)(BdrvChildRole role,
+                            int *child_flags, QDict *child_options,
                             int parent_flags, QDict *parent_options);
 
     void (*change_media)(BdrvChild *child, bool load);
diff --git a/block.c b/block.c
index 5d9a331f5b..40db0b78b9 100644
--- a/block.c
+++ b/block.c
@@ -77,6 +77,7 @@ static BlockDriverState *bdrv_open_inherit(const char *filename,
                                            QDict *options, int flags,
                                            BlockDriverState *parent,
                                            const BdrvChildClass *child_class,
+                                           BdrvChildRole child_role,
                                            Error **errp);
 
 /* If non-zero, use only whitelisted block drivers */
@@ -1153,7 +1154,8 @@ static void bdrv_temp_snapshot_options(int *child_flags, QDict *child_options,
  * Returns the options and flags that bs->file should get if a protocol driver
  * is expected, based on the given options and flags for the parent BDS
  */
-static void bdrv_inherited_options(int *child_flags, QDict *child_options,
+static void bdrv_inherited_options(BdrvChildRole role,
+                                   int *child_flags, QDict *child_options,
                                    int parent_flags, QDict *parent_options)
 {
     int flags = parent_flags;
@@ -1202,10 +1204,11 @@ const BdrvChildClass child_file = {
  * (and not only protocols) is permitted for it, based on the given options and
  * flags for the parent BDS
  */
-static void bdrv_inherited_fmt_options(int *child_flags, QDict *child_options,
+static void bdrv_inherited_fmt_options(BdrvChildRole role,
+                                       int *child_flags, QDict *child_options,
                                        int parent_flags, QDict *parent_options)
 {
-    child_file.inherit_options(child_flags, child_options,
+    child_file.inherit_options(role, child_flags, child_options,
                                parent_flags, parent_options);
 
     *child_flags &= ~(BDRV_O_PROTOCOL | BDRV_O_NO_IO);
@@ -1286,7 +1289,8 @@ static void bdrv_backing_detach(BdrvChild *c)
  * Returns the options and flags that bs->backing should get, based on the
  * given options and flags for the parent BDS
  */
-static void bdrv_backing_options(int *child_flags, QDict *child_options,
+static void bdrv_backing_options(BdrvChildRole role,
+                                 int *child_flags, QDict *child_options,
                                  int parent_flags, QDict *parent_options)
 {
     int flags = parent_flags;
@@ -2876,7 +2880,7 @@ int bdrv_open_backing_file(BlockDriverState *bs, QDict *parent_options,
     }
 
     backing_hd = bdrv_open_inherit(backing_filename, reference, options, 0, bs,
-                                   &child_backing, errp);
+                                   &child_backing, 0, errp);
     if (!backing_hd) {
         bs->open_flags |= BDRV_O_NO_BACKING;
         error_prepend(errp, "Could not open backing file: ");
@@ -2911,7 +2915,7 @@ free_exit:
 static BlockDriverState *
 bdrv_open_child_bs(const char *filename, QDict *options, const char *bdref_key,
                    BlockDriverState *parent, const BdrvChildClass *child_class,
-                   bool allow_none, Error **errp)
+                   BdrvChildRole child_role, bool allow_none, Error **errp)
 {
     BlockDriverState *bs = NULL;
     QDict *image_options;
@@ -2942,7 +2946,7 @@ bdrv_open_child_bs(const char *filename, QDict *options, const char *bdref_key,
     }
 
     bs = bdrv_open_inherit(filename, reference, image_options, 0,
-                           parent, child_class, errp);
+                           parent, child_class, child_role, errp);
     if (!bs) {
         goto done;
     }
@@ -2976,7 +2980,7 @@ BdrvChild *bdrv_open_child(const char *filename,
     BlockDriverState *bs;
 
     bs = bdrv_open_child_bs(filename, options, bdref_key, parent, child_class,
-                            allow_none, errp);
+                            child_role, allow_none, errp);
     if (bs == NULL) {
         return NULL;
     }
@@ -3020,7 +3024,7 @@ BlockDriverState *bdrv_open_blockdev_ref(BlockdevRef *ref, Error **errp)
 
     }
 
-    bs = bdrv_open_inherit(NULL, reference, qdict, 0, NULL, NULL, errp);
+    bs = bdrv_open_inherit(NULL, reference, qdict, 0, NULL, NULL, 0, errp);
     obj = NULL;
     qobject_unref(obj);
     visit_free(v);
@@ -3117,6 +3121,7 @@ static BlockDriverState *bdrv_open_inherit(const char *filename,
                                            QDict *options, int flags,
                                            BlockDriverState *parent,
                                            const BdrvChildClass *child_class,
+                                           BdrvChildRole child_role,
                                            Error **errp)
 {
     int ret;
@@ -3169,7 +3174,7 @@ static BlockDriverState *bdrv_open_inherit(const char *filename,
 
     if (child_class) {
         bs->inherits_from = parent;
-        child_class->inherit_options(&flags, options,
+        child_class->inherit_options(child_role, &flags, options,
                                      parent->open_flags, parent->options);
     }
 
@@ -3198,7 +3203,7 @@ static BlockDriverState *bdrv_open_inherit(const char *filename,
                                    flags, options);
         /* Let bdrv_backing_options() override "read-only" */
         qdict_del(options, BDRV_OPT_READ_ONLY);
-        bdrv_backing_options(&flags, options, flags, options);
+        bdrv_backing_options(0, &flags, options, flags, options);
     }
 
     bs->open_flags = flags;
@@ -3240,7 +3245,7 @@ static BlockDriverState *bdrv_open_inherit(const char *filename,
         BlockDriverState *file_bs;
 
         file_bs = bdrv_open_child_bs(filename, options, "file", bs,
-                                     &child_file, true, &local_err);
+                                     &child_file, 0, true, &local_err);
         if (local_err) {
             goto fail;
         }
@@ -3385,7 +3390,7 @@ BlockDriverState *bdrv_open(const char *filename, const char *reference,
                             QDict *options, int flags, Error **errp)
 {
     return bdrv_open_inherit(filename, reference, options, flags, NULL,
-                             NULL, errp);
+                             NULL, 0, errp);
 }
 
 /* Return true if the NULL-terminated @list contains @str */
@@ -3482,6 +3487,7 @@ static BlockReopenQueue *bdrv_reopen_queue_child(BlockReopenQueue *bs_queue,
                                                  BlockDriverState *bs,
                                                  QDict *options,
                                                  const BdrvChildClass *klass,
+                                                 BdrvChildRole role,
                                                  QDict *parent_options,
                                                  int parent_flags,
                                                  bool keep_old_opts)
@@ -3537,7 +3543,8 @@ static BlockReopenQueue *bdrv_reopen_queue_child(BlockReopenQueue *bs_queue,
     /* Inherit from parent node */
     if (parent_options) {
         flags = 0;
-        klass->inherit_options(&flags, options, parent_flags, parent_options);
+        klass->inherit_options(role, &flags, options,
+                               parent_flags, parent_options);
     } else {
         flags = bdrv_get_flags(bs);
     }
@@ -3628,7 +3635,8 @@ static BlockReopenQueue *bdrv_reopen_queue_child(BlockReopenQueue *bs_queue,
         }
 
         bdrv_reopen_queue_child(bs_queue, child->bs, new_child_options,
-                                child->klass, options, flags, child_keep_old);
+                                child->klass, child->role, options, flags,
+                                child_keep_old);
     }
 
     return bs_queue;
@@ -3638,7 +3646,7 @@ BlockReopenQueue *bdrv_reopen_queue(BlockReopenQueue *bs_queue,
                                     BlockDriverState *bs,
                                     QDict *options, bool keep_old_opts)
 {
-    return bdrv_reopen_queue_child(bs_queue, bs, options, NULL, NULL, 0,
+    return bdrv_reopen_queue_child(bs_queue, bs, options, NULL, 0, NULL, 0,
                                    keep_old_opts);
 }
 
diff --git a/block/block-backend.c b/block/block-backend.c
index efc7acb3d8..5539ca8816 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -120,7 +120,8 @@ static QTAILQ_HEAD(, BlockBackend) block_backends =
 static QTAILQ_HEAD(, BlockBackend) monitor_block_backends =
     QTAILQ_HEAD_INITIALIZER(monitor_block_backends);
 
-static void blk_root_inherit_options(int *child_flags, QDict *child_options,
+static void blk_root_inherit_options(BdrvChildRole role,
+                                     int *child_flags, QDict *child_options,
                                      int parent_flags, QDict *parent_options)
 {
     /* We're not supposed to call this function for root nodes */
diff --git a/block/vvfat.c b/block/vvfat.c
index 6cf3c74fe3..4033e4f369 100644
--- a/block/vvfat.c
+++ b/block/vvfat.c
@@ -3128,7 +3128,8 @@ static BlockDriver vvfat_write_target = {
     .bdrv_co_pwritev    = write_target_commit,
 };
 
-static void vvfat_qcow_options(int *child_flags, QDict *child_options,
+static void vvfat_qcow_options(BdrvChildRole role,
+                               int *child_flags, QDict *child_options,
                                int parent_flags, QDict *parent_options)
 {
     qdict_set_default_str(child_options, BDRV_OPT_READ_ONLY, "off");
-- 
2.26.2



^ permalink raw reply related	[flat|nested] 54+ messages in thread

* [PATCH v4 08/34] block: Pass parent_is_format to .inherit_options()
  2020-05-13 11:05 [PATCH v4 00/34] block: Introduce real BdrvChildRole Max Reitz
                   ` (6 preceding siblings ...)
  2020-05-13 11:05 ` [PATCH v4 07/34] block: Pass BdrvChildRole to .inherit_options() Max Reitz
@ 2020-05-13 11:05 ` Max Reitz
  2020-05-13 11:05 ` [PATCH v4 09/34] block: Rename bdrv_inherited_options() Max Reitz
                   ` (27 subsequent siblings)
  35 siblings, 0 replies; 54+ messages in thread
From: Max Reitz @ 2020-05-13 11:05 UTC (permalink / raw)
  To: qemu-block; +Cc: Kevin Wolf, qemu-devel, Max Reitz

We plan to unify the generic .inherit_options() functions.  The
resulting common function will need to decide whether to force-enable
format probing, force-disable it, or leave it as-is.  To make this
decision, it will need to know whether the parent node is a format node
or not (because we never want format probing if the parent is a format
node already (except for the backing chain)).

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
 include/block/block_int.h |  2 +-
 block.c                   | 37 +++++++++++++++++++++++++++----------
 block/block-backend.c     |  2 +-
 block/vvfat.c             |  2 +-
 4 files changed, 30 insertions(+), 13 deletions(-)

diff --git a/include/block/block_int.h b/include/block/block_int.h
index 8c1160a577..6245d8a18d 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -677,7 +677,7 @@ struct BdrvChildClass {
      * non-BDS parents. */
     bool parent_is_bds;
 
-    void (*inherit_options)(BdrvChildRole role,
+    void (*inherit_options)(BdrvChildRole role, bool parent_is_format,
                             int *child_flags, QDict *child_options,
                             int parent_flags, QDict *parent_options);
 
diff --git a/block.c b/block.c
index 40db0b78b9..b78e2dc141 100644
--- a/block.c
+++ b/block.c
@@ -1154,7 +1154,7 @@ static void bdrv_temp_snapshot_options(int *child_flags, QDict *child_options,
  * Returns the options and flags that bs->file should get if a protocol driver
  * is expected, based on the given options and flags for the parent BDS
  */
-static void bdrv_inherited_options(BdrvChildRole role,
+static void bdrv_inherited_options(BdrvChildRole role, bool parent_is_format,
                                    int *child_flags, QDict *child_options,
                                    int parent_flags, QDict *parent_options)
 {
@@ -1205,10 +1205,12 @@ const BdrvChildClass child_file = {
  * flags for the parent BDS
  */
 static void bdrv_inherited_fmt_options(BdrvChildRole role,
+                                       bool parent_is_format,
                                        int *child_flags, QDict *child_options,
                                        int parent_flags, QDict *parent_options)
 {
-    child_file.inherit_options(role, child_flags, child_options,
+    child_file.inherit_options(role, parent_is_format,
+                               child_flags, child_options,
                                parent_flags, parent_options);
 
     *child_flags &= ~(BDRV_O_PROTOCOL | BDRV_O_NO_IO);
@@ -1289,7 +1291,7 @@ static void bdrv_backing_detach(BdrvChild *c)
  * Returns the options and flags that bs->backing should get, based on the
  * given options and flags for the parent BDS
  */
-static void bdrv_backing_options(BdrvChildRole role,
+static void bdrv_backing_options(BdrvChildRole role, bool parent_is_format,
                                  int *child_flags, QDict *child_options,
                                  int parent_flags, QDict *parent_options)
 {
@@ -3173,8 +3175,22 @@ static BlockDriverState *bdrv_open_inherit(const char *filename,
     bs->explicit_options = qdict_clone_shallow(options);
 
     if (child_class) {
+        bool parent_is_format;
+
+        if (parent->drv) {
+            parent_is_format = parent->drv->is_format;
+        } else {
+            /*
+             * parent->drv is not set yet because this node is opened for
+             * (potential) format probing.  That means that @parent is going
+             * to be a format node.
+             */
+            parent_is_format = true;
+        }
+
         bs->inherits_from = parent;
-        child_class->inherit_options(child_role, &flags, options,
+        child_class->inherit_options(child_role, parent_is_format,
+                                     &flags, options,
                                      parent->open_flags, parent->options);
     }
 
@@ -3203,7 +3219,7 @@ static BlockDriverState *bdrv_open_inherit(const char *filename,
                                    flags, options);
         /* Let bdrv_backing_options() override "read-only" */
         qdict_del(options, BDRV_OPT_READ_ONLY);
-        bdrv_backing_options(0, &flags, options, flags, options);
+        bdrv_backing_options(0, true, &flags, options, flags, options);
     }
 
     bs->open_flags = flags;
@@ -3488,6 +3504,7 @@ static BlockReopenQueue *bdrv_reopen_queue_child(BlockReopenQueue *bs_queue,
                                                  QDict *options,
                                                  const BdrvChildClass *klass,
                                                  BdrvChildRole role,
+                                                 bool parent_is_format,
                                                  QDict *parent_options,
                                                  int parent_flags,
                                                  bool keep_old_opts)
@@ -3543,7 +3560,7 @@ static BlockReopenQueue *bdrv_reopen_queue_child(BlockReopenQueue *bs_queue,
     /* Inherit from parent node */
     if (parent_options) {
         flags = 0;
-        klass->inherit_options(role, &flags, options,
+        klass->inherit_options(role, parent_is_format, &flags, options,
                                parent_flags, parent_options);
     } else {
         flags = bdrv_get_flags(bs);
@@ -3635,8 +3652,8 @@ static BlockReopenQueue *bdrv_reopen_queue_child(BlockReopenQueue *bs_queue,
         }
 
         bdrv_reopen_queue_child(bs_queue, child->bs, new_child_options,
-                                child->klass, child->role, options, flags,
-                                child_keep_old);
+                                child->klass, child->role, bs->drv->is_format,
+                                options, flags, child_keep_old);
     }
 
     return bs_queue;
@@ -3646,8 +3663,8 @@ BlockReopenQueue *bdrv_reopen_queue(BlockReopenQueue *bs_queue,
                                     BlockDriverState *bs,
                                     QDict *options, bool keep_old_opts)
 {
-    return bdrv_reopen_queue_child(bs_queue, bs, options, NULL, 0, NULL, 0,
-                                   keep_old_opts);
+    return bdrv_reopen_queue_child(bs_queue, bs, options, NULL, 0, false,
+                                   NULL, 0, keep_old_opts);
 }
 
 /*
diff --git a/block/block-backend.c b/block/block-backend.c
index 5539ca8816..f2e81af27d 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -120,7 +120,7 @@ static QTAILQ_HEAD(, BlockBackend) block_backends =
 static QTAILQ_HEAD(, BlockBackend) monitor_block_backends =
     QTAILQ_HEAD_INITIALIZER(monitor_block_backends);
 
-static void blk_root_inherit_options(BdrvChildRole role,
+static void blk_root_inherit_options(BdrvChildRole role, bool parent_is_format,
                                      int *child_flags, QDict *child_options,
                                      int parent_flags, QDict *parent_options)
 {
diff --git a/block/vvfat.c b/block/vvfat.c
index 4033e4f369..b4c8417dbd 100644
--- a/block/vvfat.c
+++ b/block/vvfat.c
@@ -3128,7 +3128,7 @@ static BlockDriver vvfat_write_target = {
     .bdrv_co_pwritev    = write_target_commit,
 };
 
-static void vvfat_qcow_options(BdrvChildRole role,
+static void vvfat_qcow_options(BdrvChildRole role, bool parent_is_format,
                                int *child_flags, QDict *child_options,
                                int parent_flags, QDict *parent_options)
 {
-- 
2.26.2



^ permalink raw reply related	[flat|nested] 54+ messages in thread

* [PATCH v4 09/34] block: Rename bdrv_inherited_options()
  2020-05-13 11:05 [PATCH v4 00/34] block: Introduce real BdrvChildRole Max Reitz
                   ` (7 preceding siblings ...)
  2020-05-13 11:05 ` [PATCH v4 08/34] block: Pass parent_is_format " Max Reitz
@ 2020-05-13 11:05 ` Max Reitz
  2020-05-13 11:05 ` [PATCH v4 10/34] block: Add generic bdrv_inherited_options() Max Reitz
                   ` (26 subsequent siblings)
  35 siblings, 0 replies; 54+ messages in thread
From: Max Reitz @ 2020-05-13 11:05 UTC (permalink / raw)
  To: qemu-block; +Cc: Kevin Wolf, qemu-devel, Max Reitz

The other two .inherit_options implementations specify exactly for what
case they are used in their name, so do it for this one as well.

(The actual intention behind this patch is to follow it up with a
generic bdrv_inherited_options() that works for all three cases.)

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
 block.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/block.c b/block.c
index b78e2dc141..a17c29f54b 100644
--- a/block.c
+++ b/block.c
@@ -1154,9 +1154,9 @@ static void bdrv_temp_snapshot_options(int *child_flags, QDict *child_options,
  * Returns the options and flags that bs->file should get if a protocol driver
  * is expected, based on the given options and flags for the parent BDS
  */
-static void bdrv_inherited_options(BdrvChildRole role, bool parent_is_format,
-                                   int *child_flags, QDict *child_options,
-                                   int parent_flags, QDict *parent_options)
+static void bdrv_protocol_options(BdrvChildRole role, bool parent_is_format,
+                                  int *child_flags, QDict *child_options,
+                                  int parent_flags, QDict *parent_options)
 {
     int flags = parent_flags;
 
@@ -1188,7 +1188,7 @@ static void bdrv_inherited_options(BdrvChildRole role, bool parent_is_format,
 const BdrvChildClass child_file = {
     .parent_is_bds   = true,
     .get_parent_desc = bdrv_child_get_parent_desc,
-    .inherit_options = bdrv_inherited_options,
+    .inherit_options = bdrv_protocol_options,
     .drained_begin   = bdrv_child_cb_drained_begin,
     .drained_poll    = bdrv_child_cb_drained_poll,
     .drained_end     = bdrv_child_cb_drained_end,
-- 
2.26.2



^ permalink raw reply related	[flat|nested] 54+ messages in thread

* [PATCH v4 10/34] block: Add generic bdrv_inherited_options()
  2020-05-13 11:05 [PATCH v4 00/34] block: Introduce real BdrvChildRole Max Reitz
                   ` (8 preceding siblings ...)
  2020-05-13 11:05 ` [PATCH v4 09/34] block: Rename bdrv_inherited_options() Max Reitz
@ 2020-05-13 11:05 ` Max Reitz
  2020-05-13 20:13   ` Eric Blake
  2020-05-13 11:05 ` [PATCH v4 11/34] block: Use bdrv_inherited_options() Max Reitz
                   ` (25 subsequent siblings)
  35 siblings, 1 reply; 54+ messages in thread
From: Max Reitz @ 2020-05-13 11:05 UTC (permalink / raw)
  To: qemu-block; +Cc: Kevin Wolf, qemu-devel, Max Reitz

After the series this patch belongs to, we want to have a common
BdrvChildClass that encompasses all of child_file, child_format, and
child_backing.  Such a single class needs a single .inherit_options()
implementation, and this patch introduces it.

The next patch will show how the existing implementations can fall back
to it just by passing appropriate BdrvChildRole and parent_is_format
values.

Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 block.c | 81 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 81 insertions(+)

diff --git a/block.c b/block.c
index a17c29f54b..9b0e13d537 100644
--- a/block.c
+++ b/block.c
@@ -1356,6 +1356,87 @@ const BdrvChildClass child_backing = {
     .set_aio_ctx     = bdrv_child_cb_set_aio_ctx,
 };
 
+/*
+ * Returns the options and flags that a generic child of a BDS should
+ * get, based on the given options and flags for the parent BDS.
+ */
+static void __attribute__((unused))
+    bdrv_inherited_options(BdrvChildRole role, bool parent_is_format,
+                           int *child_flags, QDict *child_options,
+                           int parent_flags, QDict *parent_options)
+{
+    int flags = parent_flags;
+
+    /*
+     * First, decide whether to set, clear, or leave BDRV_O_PROTOCOL.
+     * Generally, the question to answer is: Should this child be
+     * format-probed by default?
+     */
+
+    /*
+     * Pure and non-filtered data children of non-format nodes should
+     * be probed by default (even when the node itself has BDRV_O_PROTOCOL
+     * set).  This only affects a very limited set of drivers (namely
+     * quorum and blkverify when this comment was written).
+     * Force-clear BDRV_O_PROTOCOL then.
+     */
+    if (!parent_is_format &&
+        (role & BDRV_CHILD_DATA) &&
+        !(role & (BDRV_CHILD_METADATA | BDRV_CHILD_FILTERED)))
+    {
+        flags &= ~BDRV_O_PROTOCOL;
+    }
+
+    /*
+     * All children of format nodes (except for COW children) and all
+     * metadata children in general should never be format-probed.
+     * Force-set BDRV_O_PROTOCOL then.
+     */
+    if ((parent_is_format && !(role & BDRV_CHILD_COW)) ||
+        (role & BDRV_CHILD_METADATA))
+    {
+        flags |= BDRV_O_PROTOCOL;
+    }
+
+    /*
+     * If the cache mode isn't explicitly set, inherit direct and no-flush from
+     * the parent.
+     */
+    qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_DIRECT);
+    qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_NO_FLUSH);
+    qdict_copy_default(child_options, parent_options, BDRV_OPT_FORCE_SHARE);
+
+    if (role & BDRV_CHILD_COW) {
+        /* backing files are opened read-only by default */
+        qdict_set_default_str(child_options, BDRV_OPT_READ_ONLY, "on");
+        qdict_set_default_str(child_options, BDRV_OPT_AUTO_READ_ONLY, "off");
+    } else {
+        /* Inherit the read-only option from the parent if it's not set */
+        qdict_copy_default(child_options, parent_options, BDRV_OPT_READ_ONLY);
+        qdict_copy_default(child_options, parent_options,
+                           BDRV_OPT_AUTO_READ_ONLY);
+    }
+
+    /*
+     * bdrv_co_pdiscard() respects unmap policy for the parent, so we
+     * can default to enable it on lower layers regardless of the
+     * parent option.
+     */
+    qdict_set_default_str(child_options, BDRV_OPT_DISCARD, "unmap");
+
+    /* Clear flags that only apply to the top layer */
+    flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING | BDRV_O_COPY_ON_READ);
+
+    if (role & BDRV_CHILD_METADATA) {
+        flags &= ~BDRV_O_NO_IO;
+    }
+    if (role & BDRV_CHILD_COW) {
+        flags &= ~BDRV_O_TEMPORARY;
+    }
+
+    *child_flags = flags;
+}
+
 static int bdrv_open_flags(BlockDriverState *bs, int flags)
 {
     int open_flags = flags;
-- 
2.26.2



^ permalink raw reply related	[flat|nested] 54+ messages in thread

* [PATCH v4 11/34] block: Use bdrv_inherited_options()
  2020-05-13 11:05 [PATCH v4 00/34] block: Introduce real BdrvChildRole Max Reitz
                   ` (9 preceding siblings ...)
  2020-05-13 11:05 ` [PATCH v4 10/34] block: Add generic bdrv_inherited_options() Max Reitz
@ 2020-05-13 11:05 ` Max Reitz
  2020-05-13 20:18   ` Eric Blake
  2020-05-13 11:05 ` [PATCH v4 12/34] block: Unify bdrv_child_cb_attach() Max Reitz
                   ` (24 subsequent siblings)
  35 siblings, 1 reply; 54+ messages in thread
From: Max Reitz @ 2020-05-13 11:05 UTC (permalink / raw)
  To: qemu-block; +Cc: Kevin Wolf, qemu-devel, Max Reitz

Let child_file's, child_format's, and child_backing's .inherit_options()
implementations fall back to bdrv_inherited_options() to show that it
would really work for all of these cases, if only the parents passed the
appropriate BdrvChildRole and parent_is_format values.

(Also, make bdrv_open_inherit(), the only place to explicitly call
bdrv_backing_options(), call bdrv_inherited_options() instead.)

This patch should incur only two visible changes, both for child_format
children, both of which are effectively bug fixes:

First, they no longer have discard=unmap set by default.  This reason it
was set is because bdrv_inherited_fmt_options() fell through to
bdrv_protocol_options(), and that set it because "format drivers take
care to send flushes and respect unmap policy".  None of the drivers
that use child_format for their children (quorum and blkverify) are
format drivers, though, so this reasoning does not apply here.

Second, they no longer have BDRV_O_NO_IO force-cleared.  child_format
was used solely for children that do not store any metadata and as such
will not be accessed by their parents as long as those parents do not
receive I/O themselves.  Thus, such children should inherit
BDRV_O_NO_IO.

Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 block.c | 71 +++++++++++++++------------------------------------------
 1 file changed, 19 insertions(+), 52 deletions(-)

diff --git a/block.c b/block.c
index 9b0e13d537..b3b978a092 100644
--- a/block.c
+++ b/block.c
@@ -80,6 +80,11 @@ static BlockDriverState *bdrv_open_inherit(const char *filename,
                                            BdrvChildRole child_role,
                                            Error **errp);
 
+/* TODO: Remove when no longer needed */
+static void bdrv_inherited_options(BdrvChildRole role, bool parent_is_format,
+                                   int *child_flags, QDict *child_options,
+                                   int parent_flags, QDict *parent_options);
+
 /* If non-zero, use only whitelisted block drivers */
 static int use_bdrv_whitelist;
 
@@ -1158,31 +1163,9 @@ static void bdrv_protocol_options(BdrvChildRole role, bool parent_is_format,
                                   int *child_flags, QDict *child_options,
                                   int parent_flags, QDict *parent_options)
 {
-    int flags = parent_flags;
-
-    /* Enable protocol handling, disable format probing for bs->file */
-    flags |= BDRV_O_PROTOCOL;
-
-    /* If the cache mode isn't explicitly set, inherit direct and no-flush from
-     * the parent. */
-    qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_DIRECT);
-    qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_NO_FLUSH);
-    qdict_copy_default(child_options, parent_options, BDRV_OPT_FORCE_SHARE);
-
-    /* Inherit the read-only option from the parent if it's not set */
-    qdict_copy_default(child_options, parent_options, BDRV_OPT_READ_ONLY);
-    qdict_copy_default(child_options, parent_options, BDRV_OPT_AUTO_READ_ONLY);
-
-    /* Our block drivers take care to send flushes and respect unmap policy,
-     * so we can default to enable both on lower layers regardless of the
-     * corresponding parent options. */
-    qdict_set_default_str(child_options, BDRV_OPT_DISCARD, "unmap");
-
-    /* Clear flags that only apply to the top layer */
-    flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING | BDRV_O_COPY_ON_READ |
-               BDRV_O_NO_IO);
-
-    *child_flags = flags;
+    bdrv_inherited_options(BDRV_CHILD_IMAGE, true,
+                           child_flags, child_options,
+                           parent_flags, parent_options);
 }
 
 const BdrvChildClass child_file = {
@@ -1209,11 +1192,9 @@ static void bdrv_inherited_fmt_options(BdrvChildRole role,
                                        int *child_flags, QDict *child_options,
                                        int parent_flags, QDict *parent_options)
 {
-    child_file.inherit_options(role, parent_is_format,
-                               child_flags, child_options,
-                               parent_flags, parent_options);
-
-    *child_flags &= ~(BDRV_O_PROTOCOL | BDRV_O_NO_IO);
+    bdrv_inherited_options(BDRV_CHILD_DATA, false,
+                           child_flags, child_options,
+                           parent_flags, parent_options);
 }
 
 const BdrvChildClass child_format = {
@@ -1295,23 +1276,9 @@ static void bdrv_backing_options(BdrvChildRole role, bool parent_is_format,
                                  int *child_flags, QDict *child_options,
                                  int parent_flags, QDict *parent_options)
 {
-    int flags = parent_flags;
-
-    /* The cache mode is inherited unmodified for backing files; except WCE,
-     * which is only applied on the top level (BlockBackend) */
-    qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_DIRECT);
-    qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_NO_FLUSH);
-    qdict_copy_default(child_options, parent_options, BDRV_OPT_FORCE_SHARE);
-
-    /* backing files always opened read-only */
-    qdict_set_default_str(child_options, BDRV_OPT_READ_ONLY, "on");
-    qdict_set_default_str(child_options, BDRV_OPT_AUTO_READ_ONLY, "off");
-    flags &= ~BDRV_O_COPY_ON_READ;
-
-    /* snapshot=on is handled on the top layer */
-    flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_TEMPORARY);
-
-    *child_flags = flags;
+    bdrv_inherited_options(BDRV_CHILD_COW, true,
+                           child_flags, child_options,
+                           parent_flags, parent_options);
 }
 
 static int bdrv_backing_update_filename(BdrvChild *c, BlockDriverState *base,
@@ -1360,10 +1327,9 @@ const BdrvChildClass child_backing = {
  * Returns the options and flags that a generic child of a BDS should
  * get, based on the given options and flags for the parent BDS.
  */
-static void __attribute__((unused))
-    bdrv_inherited_options(BdrvChildRole role, bool parent_is_format,
-                           int *child_flags, QDict *child_options,
-                           int parent_flags, QDict *parent_options)
+static void bdrv_inherited_options(BdrvChildRole role, bool parent_is_format,
+                                   int *child_flags, QDict *child_options,
+                                   int parent_flags, QDict *parent_options)
 {
     int flags = parent_flags;
 
@@ -3300,7 +3266,8 @@ static BlockDriverState *bdrv_open_inherit(const char *filename,
                                    flags, options);
         /* Let bdrv_backing_options() override "read-only" */
         qdict_del(options, BDRV_OPT_READ_ONLY);
-        bdrv_backing_options(0, true, &flags, options, flags, options);
+        bdrv_inherited_options(BDRV_CHILD_COW, true,
+                               &flags, options, flags, options);
     }
 
     bs->open_flags = flags;
-- 
2.26.2



^ permalink raw reply related	[flat|nested] 54+ messages in thread

* [PATCH v4 12/34] block: Unify bdrv_child_cb_attach()
  2020-05-13 11:05 [PATCH v4 00/34] block: Introduce real BdrvChildRole Max Reitz
                   ` (10 preceding siblings ...)
  2020-05-13 11:05 ` [PATCH v4 11/34] block: Use bdrv_inherited_options() Max Reitz
@ 2020-05-13 11:05 ` Max Reitz
  2020-05-13 20:26   ` Eric Blake
  2020-05-13 11:05 ` [PATCH v4 13/34] block: Unify bdrv_child_cb_detach() Max Reitz
                   ` (23 subsequent siblings)
  35 siblings, 1 reply; 54+ messages in thread
From: Max Reitz @ 2020-05-13 11:05 UTC (permalink / raw)
  To: qemu-block; +Cc: Kevin Wolf, qemu-devel, Max Reitz

Make bdrv_child_cb_attach() call bdrv_backing_attach() for children with
a COW role (and drop the reverse call from bdrv_backing_attach()), so it
can be used for any child (with a proper role set).

Because so far no child has a proper role set, we need a temporary new
callback for child_backing.attach that ensures bdrv_backing_attach() is
called for all COW children that do not have their role set yet.

(Also, move bdrv_child_cb_attach() down to group it with
bdrv_inherited_options().)

Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 block.c | 27 ++++++++++++++++++++-------
 1 file changed, 20 insertions(+), 7 deletions(-)

diff --git a/block.c b/block.c
index b3b978a092..755704a54c 100644
--- a/block.c
+++ b/block.c
@@ -84,6 +84,7 @@ static BlockDriverState *bdrv_open_inherit(const char *filename,
 static void bdrv_inherited_options(BdrvChildRole role, bool parent_is_format,
                                    int *child_flags, QDict *child_options,
                                    int parent_flags, QDict *parent_options);
+static void bdrv_child_cb_attach(BdrvChild *child);
 
 /* If non-zero, use only whitelisted block drivers */
 static int use_bdrv_whitelist;
@@ -1099,12 +1100,6 @@ static void bdrv_child_cb_drained_end(BdrvChild *child,
     bdrv_drained_end_no_poll(bs, drained_end_counter);
 }
 
-static void bdrv_child_cb_attach(BdrvChild *child)
-{
-    BlockDriverState *bs = child->opaque;
-    bdrv_apply_subtree_drain(child, bs);
-}
-
 static void bdrv_child_cb_detach(BdrvChild *child)
 {
     BlockDriverState *bs = child->opaque;
@@ -1252,7 +1247,14 @@ static void bdrv_backing_attach(BdrvChild *c)
                     parent->backing_blocker);
     bdrv_op_unblock(backing_hd, BLOCK_OP_TYPE_BACKUP_TARGET,
                     parent->backing_blocker);
+}
 
+/* XXX: Will be removed along with child_backing */
+static void bdrv_child_cb_attach_backing(BdrvChild *c)
+{
+    if (!(c->role & BDRV_CHILD_COW)) {
+        bdrv_backing_attach(c);
+    }
     bdrv_child_cb_attach(c);
 }
 
@@ -1311,7 +1313,7 @@ static int bdrv_backing_update_filename(BdrvChild *c, BlockDriverState *base,
 const BdrvChildClass child_backing = {
     .parent_is_bds   = true,
     .get_parent_desc = bdrv_child_get_parent_desc,
-    .attach          = bdrv_backing_attach,
+    .attach          = bdrv_child_cb_attach_backing,
     .detach          = bdrv_backing_detach,
     .inherit_options = bdrv_backing_options,
     .drained_begin   = bdrv_child_cb_drained_begin,
@@ -1403,6 +1405,17 @@ static void bdrv_inherited_options(BdrvChildRole role, bool parent_is_format,
     *child_flags = flags;
 }
 
+static void bdrv_child_cb_attach(BdrvChild *child)
+{
+    BlockDriverState *bs = child->opaque;
+
+    if (child->role & BDRV_CHILD_COW) {
+        bdrv_backing_attach(child);
+    }
+
+    bdrv_apply_subtree_drain(child, bs);
+}
+
 static int bdrv_open_flags(BlockDriverState *bs, int flags)
 {
     int open_flags = flags;
-- 
2.26.2



^ permalink raw reply related	[flat|nested] 54+ messages in thread

* [PATCH v4 13/34] block: Unify bdrv_child_cb_detach()
  2020-05-13 11:05 [PATCH v4 00/34] block: Introduce real BdrvChildRole Max Reitz
                   ` (11 preceding siblings ...)
  2020-05-13 11:05 ` [PATCH v4 12/34] block: Unify bdrv_child_cb_attach() Max Reitz
@ 2020-05-13 11:05 ` Max Reitz
  2020-05-13 20:27   ` Eric Blake
  2020-05-13 11:05 ` [PATCH v4 14/34] block: Add child_of_bds Max Reitz
                   ` (22 subsequent siblings)
  35 siblings, 1 reply; 54+ messages in thread
From: Max Reitz @ 2020-05-13 11:05 UTC (permalink / raw)
  To: qemu-block; +Cc: Kevin Wolf, qemu-devel, Max Reitz

Make bdrv_child_cb_detach() call bdrv_backing_detach() for children with
a COW role (and drop the reverse call from bdrv_backing_detach()), so it
can be used for any child (with a proper role set).

Because so far no child has a proper role set, we need a temporary new
callback for child_backing.detach that ensures bdrv_backing_detach() is
called for all COW children that do not have their role set yet.

(Also, move bdrv_child_cb_detach() down to group it with
bdrv_inherited_options() and bdrv_child_cb_attach().)

Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 block.c | 27 ++++++++++++++++++++-------
 1 file changed, 20 insertions(+), 7 deletions(-)

diff --git a/block.c b/block.c
index 755704a54c..f63417c06d 100644
--- a/block.c
+++ b/block.c
@@ -85,6 +85,7 @@ static void bdrv_inherited_options(BdrvChildRole role, bool parent_is_format,
                                    int *child_flags, QDict *child_options,
                                    int parent_flags, QDict *parent_options);
 static void bdrv_child_cb_attach(BdrvChild *child);
+static void bdrv_child_cb_detach(BdrvChild *child);
 
 /* If non-zero, use only whitelisted block drivers */
 static int use_bdrv_whitelist;
@@ -1100,12 +1101,6 @@ static void bdrv_child_cb_drained_end(BdrvChild *child,
     bdrv_drained_end_no_poll(bs, drained_end_counter);
 }
 
-static void bdrv_child_cb_detach(BdrvChild *child)
-{
-    BlockDriverState *bs = child->opaque;
-    bdrv_unapply_subtree_drain(child, bs);
-}
-
 static int bdrv_child_cb_inactivate(BdrvChild *child)
 {
     BlockDriverState *bs = child->opaque;
@@ -1266,7 +1261,14 @@ static void bdrv_backing_detach(BdrvChild *c)
     bdrv_op_unblock_all(c->bs, parent->backing_blocker);
     error_free(parent->backing_blocker);
     parent->backing_blocker = NULL;
+}
 
+/* XXX: Will be removed along with child_backing */
+static void bdrv_child_cb_detach_backing(BdrvChild *c)
+{
+    if (!(c->role & BDRV_CHILD_COW)) {
+        bdrv_backing_detach(c);
+    }
     bdrv_child_cb_detach(c);
 }
 
@@ -1314,7 +1316,7 @@ const BdrvChildClass child_backing = {
     .parent_is_bds   = true,
     .get_parent_desc = bdrv_child_get_parent_desc,
     .attach          = bdrv_child_cb_attach_backing,
-    .detach          = bdrv_backing_detach,
+    .detach          = bdrv_child_cb_detach_backing,
     .inherit_options = bdrv_backing_options,
     .drained_begin   = bdrv_child_cb_drained_begin,
     .drained_poll    = bdrv_child_cb_drained_poll,
@@ -1416,6 +1418,17 @@ static void bdrv_child_cb_attach(BdrvChild *child)
     bdrv_apply_subtree_drain(child, bs);
 }
 
+static void bdrv_child_cb_detach(BdrvChild *child)
+{
+    BlockDriverState *bs = child->opaque;
+
+    if (child->role & BDRV_CHILD_COW) {
+        bdrv_backing_detach(child);
+    }
+
+    bdrv_unapply_subtree_drain(child, bs);
+}
+
 static int bdrv_open_flags(BlockDriverState *bs, int flags)
 {
     int open_flags = flags;
-- 
2.26.2



^ permalink raw reply related	[flat|nested] 54+ messages in thread

* [PATCH v4 14/34] block: Add child_of_bds
  2020-05-13 11:05 [PATCH v4 00/34] block: Introduce real BdrvChildRole Max Reitz
                   ` (12 preceding siblings ...)
  2020-05-13 11:05 ` [PATCH v4 13/34] block: Unify bdrv_child_cb_detach() Max Reitz
@ 2020-05-13 11:05 ` Max Reitz
  2020-05-13 20:29   ` Eric Blake
  2020-05-13 11:05 ` [PATCH v4 15/34] block: Distinguish paths in *_format_default_perms Max Reitz
                   ` (21 subsequent siblings)
  35 siblings, 1 reply; 54+ messages in thread
From: Max Reitz @ 2020-05-13 11:05 UTC (permalink / raw)
  To: qemu-block; +Cc: Kevin Wolf, qemu-devel, Max Reitz

Any current user of child_file, child_format, and child_backing can and
should use this generic BdrvChildClass instead, as it can handle all of
these cases.  However, to be able to do so, the users must pass the
appropriate BdrvChildRole when the child is created/attached.  (The
following commits will take care of that.)

Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 include/block/block_int.h |  1 +
 block.c                   | 24 ++++++++++++++++++++++++
 2 files changed, 25 insertions(+)

diff --git a/include/block/block_int.h b/include/block/block_int.h
index 6245d8a18d..54df821d61 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -740,6 +740,7 @@ struct BdrvChildClass {
     void (*set_aio_ctx)(BdrvChild *child, AioContext *ctx, GSList **ignore);
 };
 
+extern const BdrvChildClass child_of_bds;
 extern const BdrvChildClass child_file;
 extern const BdrvChildClass child_format;
 extern const BdrvChildClass child_backing;
diff --git a/block.c b/block.c
index f63417c06d..be9bfa9d46 100644
--- a/block.c
+++ b/block.c
@@ -1429,6 +1429,30 @@ static void bdrv_child_cb_detach(BdrvChild *child)
     bdrv_unapply_subtree_drain(child, bs);
 }
 
+static int bdrv_child_cb_update_filename(BdrvChild *c, BlockDriverState *base,
+                                         const char *filename, Error **errp)
+{
+    if (c->role & BDRV_CHILD_COW) {
+        return bdrv_backing_update_filename(c, base, filename, errp);
+    }
+    return 0;
+}
+
+const BdrvChildClass child_of_bds = {
+    .parent_is_bds   = true,
+    .get_parent_desc = bdrv_child_get_parent_desc,
+    .inherit_options = bdrv_inherited_options,
+    .drained_begin   = bdrv_child_cb_drained_begin,
+    .drained_poll    = bdrv_child_cb_drained_poll,
+    .drained_end     = bdrv_child_cb_drained_end,
+    .attach          = bdrv_child_cb_attach,
+    .detach          = bdrv_child_cb_detach,
+    .inactivate      = bdrv_child_cb_inactivate,
+    .can_set_aio_ctx = bdrv_child_cb_can_set_aio_ctx,
+    .set_aio_ctx     = bdrv_child_cb_set_aio_ctx,
+    .update_filename = bdrv_child_cb_update_filename,
+};
+
 static int bdrv_open_flags(BlockDriverState *bs, int flags)
 {
     int open_flags = flags;
-- 
2.26.2



^ permalink raw reply related	[flat|nested] 54+ messages in thread

* [PATCH v4 15/34] block: Distinguish paths in *_format_default_perms
  2020-05-13 11:05 [PATCH v4 00/34] block: Introduce real BdrvChildRole Max Reitz
                   ` (13 preceding siblings ...)
  2020-05-13 11:05 ` [PATCH v4 14/34] block: Add child_of_bds Max Reitz
@ 2020-05-13 11:05 ` Max Reitz
  2020-05-13 20:30   ` Eric Blake
  2020-05-13 11:05 ` [PATCH v4 16/34] block: Pull out bdrv_default_perms_for_cow() Max Reitz
                   ` (20 subsequent siblings)
  35 siblings, 1 reply; 54+ messages in thread
From: Max Reitz @ 2020-05-13 11:05 UTC (permalink / raw)
  To: qemu-block; +Cc: Kevin Wolf, qemu-devel, Max Reitz

bdrv_format_default_perms() has one code path for backing files, and one
for storage files.  We want to pull them out into own functions, so
make sure they are completely distinct before so the next patches will
be a bit cleaner.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
 block.c | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/block.c b/block.c
index be9bfa9d46..b3e7ae70c7 100644
--- a/block.c
+++ b/block.c
@@ -2497,6 +2497,13 @@ void bdrv_format_default_perms(BlockDriverState *bs, BdrvChild *c,
             perm |= BLK_PERM_CONSISTENT_READ;
         }
         shared &= ~(BLK_PERM_WRITE | BLK_PERM_RESIZE);
+
+        if (bs->open_flags & BDRV_O_INACTIVE) {
+            shared |= BLK_PERM_WRITE | BLK_PERM_RESIZE;
+        }
+
+        *nperm = perm;
+        *nshared = shared;
     } else {
         /* We want consistent read from backing files if the parent needs it.
          * No other operations are performed on backing files. */
@@ -2513,14 +2520,14 @@ void bdrv_format_default_perms(BlockDriverState *bs, BdrvChild *c,
 
         shared |= BLK_PERM_CONSISTENT_READ | BLK_PERM_GRAPH_MOD |
                   BLK_PERM_WRITE_UNCHANGED;
-    }
 
-    if (bs->open_flags & BDRV_O_INACTIVE) {
-        shared |= BLK_PERM_WRITE | BLK_PERM_RESIZE;
-    }
+        if (bs->open_flags & BDRV_O_INACTIVE) {
+            shared |= BLK_PERM_WRITE | BLK_PERM_RESIZE;
+        }
 
-    *nperm = perm;
-    *nshared = shared;
+        *nperm = perm;
+        *nshared = shared;
+    }
 }
 
 uint64_t bdrv_qapi_perm_to_blk_perm(BlockPermission qapi_perm)
-- 
2.26.2



^ permalink raw reply related	[flat|nested] 54+ messages in thread

* [PATCH v4 16/34] block: Pull out bdrv_default_perms_for_cow()
  2020-05-13 11:05 [PATCH v4 00/34] block: Introduce real BdrvChildRole Max Reitz
                   ` (14 preceding siblings ...)
  2020-05-13 11:05 ` [PATCH v4 15/34] block: Distinguish paths in *_format_default_perms Max Reitz
@ 2020-05-13 11:05 ` Max Reitz
  2020-05-13 20:33   ` Eric Blake
  2020-05-13 11:05 ` [PATCH v4 17/34] block: Pull out bdrv_default_perms_for_storage() Max Reitz
                   ` (19 subsequent siblings)
  35 siblings, 1 reply; 54+ messages in thread
From: Max Reitz @ 2020-05-13 11:05 UTC (permalink / raw)
  To: qemu-block; +Cc: Kevin Wolf, qemu-devel, Max Reitz

Right now, bdrv_format_default_perms() is used by format parents
(generally). We want to switch to a model where most parents use a
single BdrvChildClass, which then decides the permissions based on the
child role. To do so, we have to split bdrv_format_default_perms() into
separate functions for each such role.

Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 block.c | 62 +++++++++++++++++++++++++++++++++++++--------------------
 1 file changed, 40 insertions(+), 22 deletions(-)

diff --git a/block.c b/block.c
index b3e7ae70c7..b12222a471 100644
--- a/block.c
+++ b/block.c
@@ -2468,6 +2468,44 @@ void bdrv_filter_default_perms(BlockDriverState *bs, BdrvChild *c,
     *nshared = (shared & DEFAULT_PERM_PASSTHROUGH) | DEFAULT_PERM_UNCHANGED;
 }
 
+static void bdrv_default_perms_for_cow(BlockDriverState *bs, BdrvChild *c,
+                                       const BdrvChildClass *child_class,
+                                       BdrvChildRole role,
+                                       BlockReopenQueue *reopen_queue,
+                                       uint64_t perm, uint64_t shared,
+                                       uint64_t *nperm, uint64_t *nshared)
+{
+    assert(child_class == &child_backing ||
+           (child_class == &child_of_bds && (role & BDRV_CHILD_COW)));
+
+    /*
+     * We want consistent read from backing files if the parent needs it.
+     * No other operations are performed on backing files.
+     */
+    perm &= BLK_PERM_CONSISTENT_READ;
+
+    /*
+     * If the parent can deal with changing data, we're okay with a
+     * writable and resizable backing file.
+     * TODO Require !(perm & BLK_PERM_CONSISTENT_READ), too?
+     */
+    if (shared & BLK_PERM_WRITE) {
+        shared = BLK_PERM_WRITE | BLK_PERM_RESIZE;
+    } else {
+        shared = 0;
+    }
+
+    shared |= BLK_PERM_CONSISTENT_READ | BLK_PERM_GRAPH_MOD |
+              BLK_PERM_WRITE_UNCHANGED;
+
+    if (bs->open_flags & BDRV_O_INACTIVE) {
+        shared |= BLK_PERM_WRITE | BLK_PERM_RESIZE;
+    }
+
+    *nperm = perm;
+    *nshared = shared;
+}
+
 void bdrv_format_default_perms(BlockDriverState *bs, BdrvChild *c,
                                const BdrvChildClass *child_class,
                                BdrvChildRole role,
@@ -2505,28 +2543,8 @@ void bdrv_format_default_perms(BlockDriverState *bs, BdrvChild *c,
         *nperm = perm;
         *nshared = shared;
     } else {
-        /* We want consistent read from backing files if the parent needs it.
-         * No other operations are performed on backing files. */
-        perm &= BLK_PERM_CONSISTENT_READ;
-
-        /* If the parent can deal with changing data, we're okay with a
-         * writable and resizable backing file. */
-        /* TODO Require !(perm & BLK_PERM_CONSISTENT_READ), too? */
-        if (shared & BLK_PERM_WRITE) {
-            shared = BLK_PERM_WRITE | BLK_PERM_RESIZE;
-        } else {
-            shared = 0;
-        }
-
-        shared |= BLK_PERM_CONSISTENT_READ | BLK_PERM_GRAPH_MOD |
-                  BLK_PERM_WRITE_UNCHANGED;
-
-        if (bs->open_flags & BDRV_O_INACTIVE) {
-            shared |= BLK_PERM_WRITE | BLK_PERM_RESIZE;
-        }
-
-        *nperm = perm;
-        *nshared = shared;
+        bdrv_default_perms_for_cow(bs, c, child_class, role, reopen_queue,
+                                   perm, shared, nperm, nshared);
     }
 }
 
-- 
2.26.2



^ permalink raw reply related	[flat|nested] 54+ messages in thread

* [PATCH v4 17/34] block: Pull out bdrv_default_perms_for_storage()
  2020-05-13 11:05 [PATCH v4 00/34] block: Introduce real BdrvChildRole Max Reitz
                   ` (15 preceding siblings ...)
  2020-05-13 11:05 ` [PATCH v4 16/34] block: Pull out bdrv_default_perms_for_cow() Max Reitz
@ 2020-05-13 11:05 ` Max Reitz
  2020-05-13 11:05 ` [PATCH v4 18/34] block: Relax *perms_for_storage for data children Max Reitz
                   ` (18 subsequent siblings)
  35 siblings, 0 replies; 54+ messages in thread
From: Max Reitz @ 2020-05-13 11:05 UTC (permalink / raw)
  To: qemu-block; +Cc: Kevin Wolf, qemu-devel, Max Reitz

Right now, bdrv_format_default_perms() is used by format parents
(generally). We want to switch to a model where most parents use a
single BdrvChildClass, which then decides the permissions based on the
child role. To do so, we have to split bdrv_format_default_perms() into
separate functions for each such role.

Note that bdrv_default_perms_for_storage() currently handles all DATA |
METADATA children.  A follow-up patch is going to split it further into
one function for each case.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
 block.c | 71 +++++++++++++++++++++++++++++++++++++--------------------
 1 file changed, 46 insertions(+), 25 deletions(-)

diff --git a/block.c b/block.c
index b12222a471..5d17aa1cc3 100644
--- a/block.c
+++ b/block.c
@@ -2506,6 +2506,50 @@ static void bdrv_default_perms_for_cow(BlockDriverState *bs, BdrvChild *c,
     *nshared = shared;
 }
 
+static void bdrv_default_perms_for_storage(BlockDriverState *bs, BdrvChild *c,
+                                           const BdrvChildClass *child_class,
+                                           BdrvChildRole role,
+                                           BlockReopenQueue *reopen_queue,
+                                           uint64_t perm, uint64_t shared,
+                                           uint64_t *nperm, uint64_t *nshared)
+{
+    int flags;
+
+    assert(child_class == &child_file ||
+           (child_class == &child_of_bds &&
+            (role & (BDRV_CHILD_METADATA | BDRV_CHILD_DATA))));
+
+    flags = bdrv_reopen_get_flags(reopen_queue, bs);
+
+    /*
+     * Apart from the modifications below, the same permissions are
+     * forwarded and left alone as for filters
+     */
+    bdrv_filter_default_perms(bs, c, child_class, role, reopen_queue,
+                              perm, shared, &perm, &shared);
+
+    /* Format drivers may touch metadata even if the guest doesn't write */
+    if (bdrv_is_writable_after_reopen(bs, reopen_queue)) {
+        perm |= BLK_PERM_WRITE | BLK_PERM_RESIZE;
+    }
+
+    /*
+     * bs->file always needs to be consistent because of the metadata. We
+     * can never allow other users to resize or write to it.
+     */
+    if (!(flags & BDRV_O_NO_IO)) {
+        perm |= BLK_PERM_CONSISTENT_READ;
+    }
+    shared &= ~(BLK_PERM_WRITE | BLK_PERM_RESIZE);
+
+    if (bs->open_flags & BDRV_O_INACTIVE) {
+        shared |= BLK_PERM_WRITE | BLK_PERM_RESIZE;
+    }
+
+    *nperm = perm;
+    *nshared = shared;
+}
+
 void bdrv_format_default_perms(BlockDriverState *bs, BdrvChild *c,
                                const BdrvChildClass *child_class,
                                BdrvChildRole role,
@@ -2517,31 +2561,8 @@ void bdrv_format_default_perms(BlockDriverState *bs, BdrvChild *c,
     assert(child_class == &child_backing || child_class == &child_file);
 
     if (!backing) {
-        int flags = bdrv_reopen_get_flags(reopen_queue, bs);
-
-        /* Apart from the modifications below, the same permissions are
-         * forwarded and left alone as for filters */
-        bdrv_filter_default_perms(bs, c, child_class, role, reopen_queue,
-                                  perm, shared, &perm, &shared);
-
-        /* Format drivers may touch metadata even if the guest doesn't write */
-        if (bdrv_is_writable_after_reopen(bs, reopen_queue)) {
-            perm |= BLK_PERM_WRITE | BLK_PERM_RESIZE;
-        }
-
-        /* bs->file always needs to be consistent because of the metadata. We
-         * can never allow other users to resize or write to it. */
-        if (!(flags & BDRV_O_NO_IO)) {
-            perm |= BLK_PERM_CONSISTENT_READ;
-        }
-        shared &= ~(BLK_PERM_WRITE | BLK_PERM_RESIZE);
-
-        if (bs->open_flags & BDRV_O_INACTIVE) {
-            shared |= BLK_PERM_WRITE | BLK_PERM_RESIZE;
-        }
-
-        *nperm = perm;
-        *nshared = shared;
+        bdrv_default_perms_for_storage(bs, c, child_class, role, reopen_queue,
+                                       perm, shared, nperm, nshared);
     } else {
         bdrv_default_perms_for_cow(bs, c, child_class, role, reopen_queue,
                                    perm, shared, nperm, nshared);
-- 
2.26.2



^ permalink raw reply related	[flat|nested] 54+ messages in thread

* [PATCH v4 18/34] block: Relax *perms_for_storage for data children
  2020-05-13 11:05 [PATCH v4 00/34] block: Introduce real BdrvChildRole Max Reitz
                   ` (16 preceding siblings ...)
  2020-05-13 11:05 ` [PATCH v4 17/34] block: Pull out bdrv_default_perms_for_storage() Max Reitz
@ 2020-05-13 11:05 ` Max Reitz
  2020-05-13 20:38   ` Eric Blake
  2020-05-13 11:05 ` [PATCH v4 19/34] block: Add bdrv_default_perms() Max Reitz
                   ` (17 subsequent siblings)
  35 siblings, 1 reply; 54+ messages in thread
From: Max Reitz @ 2020-05-13 11:05 UTC (permalink / raw)
  To: qemu-block; +Cc: Kevin Wolf, qemu-devel, Max Reitz

We can be less restrictive about pure data children than those with
metadata on them, so let bdrv_default_perms_for_storage() handle
metadata children differently from pure data children.

As explained in the code, the restrictions on metadata children are
strictly stricter than those for pure data children, so in theory we
just have to distinguish between pure-data and all other storage
children (pure metadata or data+metadata).  In practice, that is not
obvious, though, so we have two independent code paths for metadata and
for data children, and data+metadata children will go through both
(without the path for data children doing anything meaningful).

Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 block.c | 58 +++++++++++++++++++++++++++++++++++++++++++++++----------
 1 file changed, 48 insertions(+), 10 deletions(-)

diff --git a/block.c b/block.c
index 5d17aa1cc3..5ff6cbd796 100644
--- a/block.c
+++ b/block.c
@@ -2528,19 +2528,57 @@ static void bdrv_default_perms_for_storage(BlockDriverState *bs, BdrvChild *c,
     bdrv_filter_default_perms(bs, c, child_class, role, reopen_queue,
                               perm, shared, &perm, &shared);
 
-    /* Format drivers may touch metadata even if the guest doesn't write */
-    if (bdrv_is_writable_after_reopen(bs, reopen_queue)) {
-        perm |= BLK_PERM_WRITE | BLK_PERM_RESIZE;
+    if (role & BDRV_CHILD_METADATA) {
+        /* Format drivers may touch metadata even if the guest doesn't write */
+        if (bdrv_is_writable_after_reopen(bs, reopen_queue)) {
+            perm |= BLK_PERM_WRITE | BLK_PERM_RESIZE;
+        }
+
+        /*
+         * bs->file always needs to be consistent because of the
+         * metadata. We can never allow other users to resize or write
+         * to it.
+         */
+        if (!(flags & BDRV_O_NO_IO)) {
+            perm |= BLK_PERM_CONSISTENT_READ;
+        }
+        shared &= ~(BLK_PERM_WRITE | BLK_PERM_RESIZE);
     }
 
-    /*
-     * bs->file always needs to be consistent because of the metadata. We
-     * can never allow other users to resize or write to it.
-     */
-    if (!(flags & BDRV_O_NO_IO)) {
-        perm |= BLK_PERM_CONSISTENT_READ;
+    if (role & BDRV_CHILD_DATA) {
+        /*
+         * Technically, everything in this block is a subset of the
+         * BDRV_CHILD_METADATA path taken above, and so this could
+         * be an "else if" branch.  However, that is not obvious, and
+         * this function is not performance critical, therefore we let
+         * this be an independent "if".
+         */
+
+        /*
+         * We cannot allow other users to resize the file because the
+         * format driver might have some assumptions about the size
+         * (e.g. because it is stored in metadata, or because the file
+         * is split into fixed-size data files).
+         */
+        shared &= ~BLK_PERM_RESIZE;
+
+        /*
+         * WRITE_UNCHANGED often cannot be performed as such on the
+         * data file.  For example, the qcow2 driver may still need to
+         * write copied clusters on copy-on-read.
+         */
+        if (perm & BLK_PERM_WRITE_UNCHANGED) {
+            perm |= BLK_PERM_WRITE;
+        }
+
+        /*
+         * If the data file is written to, the format driver may
+         * expect to be able to resize it by writing beyond the EOF.
+         */
+        if (perm & BLK_PERM_WRITE) {
+            perm |= BLK_PERM_RESIZE;
+        }
     }
-    shared &= ~(BLK_PERM_WRITE | BLK_PERM_RESIZE);
 
     if (bs->open_flags & BDRV_O_INACTIVE) {
         shared |= BLK_PERM_WRITE | BLK_PERM_RESIZE;
-- 
2.26.2



^ permalink raw reply related	[flat|nested] 54+ messages in thread

* [PATCH v4 19/34] block: Add bdrv_default_perms()
  2020-05-13 11:05 [PATCH v4 00/34] block: Introduce real BdrvChildRole Max Reitz
                   ` (17 preceding siblings ...)
  2020-05-13 11:05 ` [PATCH v4 18/34] block: Relax *perms_for_storage for data children Max Reitz
@ 2020-05-13 11:05 ` Max Reitz
  2020-05-13 20:43   ` Eric Blake
  2020-05-13 11:05 ` [PATCH v4 20/34] raw-format: Split raw_read_options() Max Reitz
                   ` (16 subsequent siblings)
  35 siblings, 1 reply; 54+ messages in thread
From: Max Reitz @ 2020-05-13 11:05 UTC (permalink / raw)
  To: qemu-block; +Cc: Kevin Wolf, qemu-devel, Max Reitz

This callback can be used by BDSs that use child_of_bds with the
appropriate BdrvChildRole for their children.

Also, make bdrv_format_default_perms() use it for child_of_bds children
(just a temporary solution until we can drop bdrv_format_default_perms()
altogether).

Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 include/block/block_int.h | 11 +++++++++++
 block.c                   | 32 ++++++++++++++++++++++++++++++++
 2 files changed, 43 insertions(+)

diff --git a/include/block/block_int.h b/include/block/block_int.h
index 54df821d61..3a9dda9be7 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -1288,6 +1288,17 @@ void bdrv_format_default_perms(BlockDriverState *bs, BdrvChild *c,
 bool bdrv_recurse_can_replace(BlockDriverState *bs,
                               BlockDriverState *to_replace);
 
+/*
+ * Default implementation for BlockDriver.bdrv_child_perm() that can
+ * be used by block filters and image formats, as long as they use the
+ * child_of_bds child class and set an appropriate BdrvChildRole.
+ */
+void bdrv_default_perms(BlockDriverState *bs, BdrvChild *c,
+                        const BdrvChildClass *child_class, BdrvChildRole role,
+                        BlockReopenQueue *reopen_queue,
+                        uint64_t perm, uint64_t shared,
+                        uint64_t *nperm, uint64_t *nshared);
+
 /*
  * Default implementation for drivers to pass bdrv_co_block_status() to
  * their file.
diff --git a/block.c b/block.c
index 5ff6cbd796..088727fdbe 100644
--- a/block.c
+++ b/block.c
@@ -2596,6 +2596,13 @@ void bdrv_format_default_perms(BlockDriverState *bs, BdrvChild *c,
                                uint64_t *nperm, uint64_t *nshared)
 {
     bool backing = (child_class == &child_backing);
+
+    if (child_class == &child_of_bds) {
+        bdrv_default_perms(bs, c, child_class, role, reopen_queue,
+                           perm, shared, nperm, nshared);
+        return;
+    }
+
     assert(child_class == &child_backing || child_class == &child_file);
 
     if (!backing) {
@@ -2607,6 +2614,31 @@ void bdrv_format_default_perms(BlockDriverState *bs, BdrvChild *c,
     }
 }
 
+void bdrv_default_perms(BlockDriverState *bs, BdrvChild *c,
+                        const BdrvChildClass *child_class, BdrvChildRole role,
+                        BlockReopenQueue *reopen_queue,
+                        uint64_t perm, uint64_t shared,
+                        uint64_t *nperm, uint64_t *nshared)
+{
+    assert(child_class == &child_of_bds);
+
+    if (role & BDRV_CHILD_FILTERED) {
+        assert(!(role & (BDRV_CHILD_DATA | BDRV_CHILD_METADATA |
+                         BDRV_CHILD_COW)));
+        bdrv_filter_default_perms(bs, c, child_class, role, reopen_queue,
+                                  perm, shared, nperm, nshared);
+    } else if (role & BDRV_CHILD_COW) {
+        assert(!(role & (BDRV_CHILD_DATA | BDRV_CHILD_METADATA)));
+        bdrv_default_perms_for_cow(bs, c, child_class, role, reopen_queue,
+                                   perm, shared, nperm, nshared);
+    } else if (role & (BDRV_CHILD_METADATA | BDRV_CHILD_DATA)) {
+        bdrv_default_perms_for_storage(bs, c, child_class, role, reopen_queue,
+                                       perm, shared, nperm, nshared);
+    } else {
+        g_assert_not_reached();
+    }
+}
+
 uint64_t bdrv_qapi_perm_to_blk_perm(BlockPermission qapi_perm)
 {
     static const uint64_t permissions[] = {
-- 
2.26.2



^ permalink raw reply related	[flat|nested] 54+ messages in thread

* [PATCH v4 20/34] raw-format: Split raw_read_options()
  2020-05-13 11:05 [PATCH v4 00/34] block: Introduce real BdrvChildRole Max Reitz
                   ` (18 preceding siblings ...)
  2020-05-13 11:05 ` [PATCH v4 19/34] block: Add bdrv_default_perms() Max Reitz
@ 2020-05-13 11:05 ` Max Reitz
  2020-05-13 11:05 ` [PATCH v4 21/34] block: Switch child_format users to child_of_bds Max Reitz
                   ` (15 subsequent siblings)
  35 siblings, 0 replies; 54+ messages in thread
From: Max Reitz @ 2020-05-13 11:05 UTC (permalink / raw)
  To: qemu-block; +Cc: Kevin Wolf, qemu-devel, Max Reitz

Split raw_read_options() into one function that actually just reads the
options, and another that applies them.  This will allow us to detect
whether the user has specified any options before attaching the file
child (so we can decide on its role based on the options).

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
 block/raw-format.c | 110 ++++++++++++++++++++++++++-------------------
 1 file changed, 65 insertions(+), 45 deletions(-)

diff --git a/block/raw-format.c b/block/raw-format.c
index 4b8d4ce8be..824fe70686 100644
--- a/block/raw-format.c
+++ b/block/raw-format.c
@@ -71,20 +71,13 @@ static QemuOptsList raw_create_opts = {
     }
 };
 
-static int raw_read_options(QDict *options, BlockDriverState *bs,
-    BDRVRawState *s, Error **errp)
+static int raw_read_options(QDict *options, uint64_t *offset, bool *has_size,
+                            uint64_t *size, Error **errp)
 {
     Error *local_err = NULL;
     QemuOpts *opts = NULL;
-    int64_t real_size = 0;
     int ret;
 
-    real_size = bdrv_getlength(bs->file->bs);
-    if (real_size < 0) {
-        error_setg_errno(errp, -real_size, "Could not get image size");
-        return real_size;
-    }
-
     opts = qemu_opts_create(&raw_runtime_opts, NULL, 0, &error_abort);
     qemu_opts_absorb_qdict(opts, options, &local_err);
     if (local_err) {
@@ -93,64 +86,84 @@ static int raw_read_options(QDict *options, BlockDriverState *bs,
         goto end;
     }
 
-    s->offset = qemu_opt_get_size(opts, "offset", 0);
-    if (s->offset > real_size) {
-        error_setg(errp, "Offset (%" PRIu64 ") cannot be greater than "
-            "size of the containing file (%" PRId64 ")",
-            s->offset, real_size);
-        ret = -EINVAL;
-        goto end;
-    }
+    *offset = qemu_opt_get_size(opts, "offset", 0);
+    *has_size = qemu_opt_find(opts, "size");
+    *size = qemu_opt_get_size(opts, "size", 0);
 
-    if (qemu_opt_find(opts, "size") != NULL) {
-        s->size = qemu_opt_get_size(opts, "size", 0);
-        s->has_size = true;
-    } else {
-        s->has_size = false;
-        s->size = real_size - s->offset;
+    ret = 0;
+end:
+    qemu_opts_del(opts);
+    return ret;
+}
+
+static int raw_apply_options(BlockDriverState *bs, BDRVRawState *s,
+                             uint64_t offset, bool has_size, uint64_t size,
+                             Error **errp)
+{
+    int64_t real_size = 0;
+
+    real_size = bdrv_getlength(bs->file->bs);
+    if (real_size < 0) {
+        error_setg_errno(errp, -real_size, "Could not get image size");
+        return real_size;
     }
 
     /* Check size and offset */
-    if ((real_size - s->offset) < s->size) {
+    if (offset > real_size) {
+        error_setg(errp, "Offset (%" PRIu64 ") cannot be greater than "
+                   "size of the containing file (%" PRId64 ")",
+                   s->offset, real_size);
+        return -EINVAL;
+    }
+
+    if (has_size && (real_size - offset) < size) {
         error_setg(errp, "The sum of offset (%" PRIu64 ") and size "
-            "(%" PRIu64 ") has to be smaller or equal to the "
-            " actual size of the containing file (%" PRId64 ")",
-            s->offset, s->size, real_size);
-        ret = -EINVAL;
-        goto end;
+                   "(%" PRIu64 ") has to be smaller or equal to the "
+                   " actual size of the containing file (%" PRId64 ")",
+                   s->offset, s->size, real_size);
+        return -EINVAL;
     }
 
     /* Make sure size is multiple of BDRV_SECTOR_SIZE to prevent rounding
      * up and leaking out of the specified area. */
-    if (s->has_size && !QEMU_IS_ALIGNED(s->size, BDRV_SECTOR_SIZE)) {
+    if (has_size && !QEMU_IS_ALIGNED(size, BDRV_SECTOR_SIZE)) {
         error_setg(errp, "Specified size is not multiple of %llu",
-            BDRV_SECTOR_SIZE);
-        ret = -EINVAL;
-        goto end;
+                   BDRV_SECTOR_SIZE);
+        return -EINVAL;
     }
 
-    ret = 0;
-
-end:
+    s->offset = offset;
+    s->has_size = has_size;
+    s->size = has_size ? size : real_size - offset;
 
-    qemu_opts_del(opts);
-
-    return ret;
+    return 0;
 }
 
 static int raw_reopen_prepare(BDRVReopenState *reopen_state,
                               BlockReopenQueue *queue, Error **errp)
 {
+    bool has_size;
+    uint64_t offset, size;
+    int ret;
+
     assert(reopen_state != NULL);
     assert(reopen_state->bs != NULL);
 
     reopen_state->opaque = g_new0(BDRVRawState, 1);
 
-    return raw_read_options(
-        reopen_state->options,
-        reopen_state->bs,
-        reopen_state->opaque,
-        errp);
+    ret = raw_read_options(reopen_state->options, &offset, &has_size, &size,
+                           errp);
+    if (ret < 0) {
+        return ret;
+    }
+
+    ret = raw_apply_options(reopen_state->bs, reopen_state->opaque,
+                            offset, has_size, size, errp);
+    if (ret < 0) {
+        return ret;
+    }
+
+    return 0;
 }
 
 static void raw_reopen_commit(BDRVReopenState *state)
@@ -426,8 +439,15 @@ static int raw_open(BlockDriverState *bs, QDict *options, int flags,
                     Error **errp)
 {
     BDRVRawState *s = bs->opaque;
+    bool has_size;
+    uint64_t offset, size;
     int ret;
 
+    ret = raw_read_options(options, &offset, &has_size, &size, errp);
+    if (ret < 0) {
+        return ret;
+    }
+
     bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 0,
                                false, errp);
     if (!bs->file) {
@@ -455,7 +475,7 @@ static int raw_open(BlockDriverState *bs, QDict *options, int flags,
                 bs->file->bs->filename);
     }
 
-    ret = raw_read_options(options, bs, s, errp);
+    ret = raw_apply_options(bs, s, offset, has_size, size, errp);
     if (ret < 0) {
         return ret;
     }
-- 
2.26.2



^ permalink raw reply related	[flat|nested] 54+ messages in thread

* [PATCH v4 21/34] block: Switch child_format users to child_of_bds
  2020-05-13 11:05 [PATCH v4 00/34] block: Introduce real BdrvChildRole Max Reitz
                   ` (19 preceding siblings ...)
  2020-05-13 11:05 ` [PATCH v4 20/34] raw-format: Split raw_read_options() Max Reitz
@ 2020-05-13 11:05 ` Max Reitz
  2020-05-13 11:05 ` [PATCH v4 22/34] block: Drop child_format Max Reitz
                   ` (14 subsequent siblings)
  35 siblings, 0 replies; 54+ messages in thread
From: Max Reitz @ 2020-05-13 11:05 UTC (permalink / raw)
  To: qemu-block; +Cc: Kevin Wolf, qemu-devel, Max Reitz

Both users (quorum and blkverify) use child_format for
not-really-filtered children, so the appropriate BdrvChildRole in both
cases is DATA.  (Note that this will cause bdrv_inherited_options() to
force-allow format probing.)

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
 block/blkverify.c | 4 ++--
 block/quorum.c    | 6 ++++--
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/block/blkverify.c b/block/blkverify.c
index ba4f6d7b7c..1684b7aa2e 100644
--- a/block/blkverify.c
+++ b/block/blkverify.c
@@ -134,8 +134,8 @@ static int blkverify_open(BlockDriverState *bs, QDict *options, int flags,
 
     /* Open the test file */
     s->test_file = bdrv_open_child(qemu_opt_get(opts, "x-image"), options,
-                                   "test", bs, &child_format, 0, false,
-                                   &local_err);
+                                   "test", bs, &child_of_bds, BDRV_CHILD_DATA,
+                                   false, &local_err);
     if (local_err) {
         ret = -EINVAL;
         error_propagate(errp, local_err);
diff --git a/block/quorum.c b/block/quorum.c
index d37b77a522..616ac3a927 100644
--- a/block/quorum.c
+++ b/block/quorum.c
@@ -977,7 +977,8 @@ static int quorum_open(BlockDriverState *bs, QDict *options, int flags,
         assert(ret < 32);
 
         s->children[i] = bdrv_open_child(NULL, options, indexstr, bs,
-                                         &child_format, 0, false, &local_err);
+                                         &child_of_bds, BDRV_CHILD_DATA, false,
+                                         &local_err);
         if (local_err) {
             ret = -EINVAL;
             goto close_exit;
@@ -1053,7 +1054,8 @@ static void quorum_add_child(BlockDriverState *bs, BlockDriverState *child_bs,
     /* We can safely add the child now */
     bdrv_ref(child_bs);
 
-    child = bdrv_attach_child(bs, child_bs, indexstr, &child_format, 0, errp);
+    child = bdrv_attach_child(bs, child_bs, indexstr, &child_of_bds,
+                              BDRV_CHILD_DATA, errp);
     if (child == NULL) {
         s->next_child_index--;
         goto out;
-- 
2.26.2



^ permalink raw reply related	[flat|nested] 54+ messages in thread

* [PATCH v4 22/34] block: Drop child_format
  2020-05-13 11:05 [PATCH v4 00/34] block: Introduce real BdrvChildRole Max Reitz
                   ` (20 preceding siblings ...)
  2020-05-13 11:05 ` [PATCH v4 21/34] block: Switch child_format users to child_of_bds Max Reitz
@ 2020-05-13 11:05 ` Max Reitz
  2020-05-13 11:05 ` [PATCH v4 23/34] block: Make backing files child_of_bds children Max Reitz
                   ` (13 subsequent siblings)
  35 siblings, 0 replies; 54+ messages in thread
From: Max Reitz @ 2020-05-13 11:05 UTC (permalink / raw)
  To: qemu-block; +Cc: Kevin Wolf, qemu-devel, Max Reitz

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
 include/block/block_int.h |  1 -
 block.c                   | 29 -----------------------------
 2 files changed, 30 deletions(-)

diff --git a/include/block/block_int.h b/include/block/block_int.h
index 3a9dda9be7..4b09fa1124 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -742,7 +742,6 @@ struct BdrvChildClass {
 
 extern const BdrvChildClass child_of_bds;
 extern const BdrvChildClass child_file;
-extern const BdrvChildClass child_format;
 extern const BdrvChildClass child_backing;
 
 struct BdrvChild {
diff --git a/block.c b/block.c
index 088727fdbe..85b4f947ba 100644
--- a/block.c
+++ b/block.c
@@ -1172,35 +1172,6 @@ const BdrvChildClass child_file = {
     .set_aio_ctx     = bdrv_child_cb_set_aio_ctx,
 };
 
-/*
- * Returns the options and flags that bs->file should get if the use of formats
- * (and not only protocols) is permitted for it, based on the given options and
- * flags for the parent BDS
- */
-static void bdrv_inherited_fmt_options(BdrvChildRole role,
-                                       bool parent_is_format,
-                                       int *child_flags, QDict *child_options,
-                                       int parent_flags, QDict *parent_options)
-{
-    bdrv_inherited_options(BDRV_CHILD_DATA, false,
-                           child_flags, child_options,
-                           parent_flags, parent_options);
-}
-
-const BdrvChildClass child_format = {
-    .parent_is_bds   = true,
-    .get_parent_desc = bdrv_child_get_parent_desc,
-    .inherit_options = bdrv_inherited_fmt_options,
-    .drained_begin   = bdrv_child_cb_drained_begin,
-    .drained_poll    = bdrv_child_cb_drained_poll,
-    .drained_end     = bdrv_child_cb_drained_end,
-    .attach          = bdrv_child_cb_attach,
-    .detach          = bdrv_child_cb_detach,
-    .inactivate      = bdrv_child_cb_inactivate,
-    .can_set_aio_ctx = bdrv_child_cb_can_set_aio_ctx,
-    .set_aio_ctx     = bdrv_child_cb_set_aio_ctx,
-};
-
 static void bdrv_backing_attach(BdrvChild *c)
 {
     BlockDriverState *parent = c->opaque;
-- 
2.26.2



^ permalink raw reply related	[flat|nested] 54+ messages in thread

* [PATCH v4 23/34] block: Make backing files child_of_bds children
  2020-05-13 11:05 [PATCH v4 00/34] block: Introduce real BdrvChildRole Max Reitz
                   ` (21 preceding siblings ...)
  2020-05-13 11:05 ` [PATCH v4 22/34] block: Drop child_format Max Reitz
@ 2020-05-13 11:05 ` Max Reitz
  2020-05-13 20:46   ` Eric Blake
  2020-05-13 11:05 ` [PATCH v4 24/34] block: Drop child_backing Max Reitz
                   ` (12 subsequent siblings)
  35 siblings, 1 reply; 54+ messages in thread
From: Max Reitz @ 2020-05-13 11:05 UTC (permalink / raw)
  To: qemu-block; +Cc: Kevin Wolf, qemu-devel, Max Reitz

Make all parents of backing files pass the appropriate BdrvChildRole.
By doing so, we can switch their BdrvChildClass over to the generic
child_of_bds, which will do the right thing when given a correct
BdrvChildRole.

Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 block.c                 | 26 ++++++++++++++++++++------
 block/backup-top.c      |  2 +-
 block/vvfat.c           |  3 ++-
 tests/test-bdrv-drain.c | 13 +++++++------
 4 files changed, 30 insertions(+), 14 deletions(-)

diff --git a/block.c b/block.c
index 85b4f947ba..131ae20ffc 100644
--- a/block.c
+++ b/block.c
@@ -2941,6 +2941,20 @@ static bool bdrv_inherits_from_recursive(BlockDriverState *child,
     return child != NULL;
 }
 
+/*
+ * Return the BdrvChildRole for @bs's backing child.  bs->backing is
+ * mostly used for COW backing children (role = COW), but also for
+ * filtered children (role = FILTERED | PRIMARY).
+ */
+static BdrvChildRole bdrv_backing_role(BlockDriverState *bs)
+{
+    if (bs->drv && bs->drv->is_filter) {
+        return BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY;
+    } else {
+        return BDRV_CHILD_COW;
+    }
+}
+
 /*
  * Sets the backing file link of a BDS. A new reference is created; callers
  * which don't need their own reference any more must call bdrv_unref().
@@ -2968,8 +2982,8 @@ void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd,
         goto out;
     }
 
-    bs->backing = bdrv_attach_child(bs, backing_hd, "backing", &child_backing,
-                                    0, errp);
+    bs->backing = bdrv_attach_child(bs, backing_hd, "backing", &child_of_bds,
+                                    bdrv_backing_role(bs), errp);
     /* If backing_hd was already part of bs's backing chain, and
      * inherits_from pointed recursively to bs then let's update it to
      * point directly to bs (else it will become NULL). */
@@ -3066,7 +3080,7 @@ int bdrv_open_backing_file(BlockDriverState *bs, QDict *parent_options,
     }
 
     backing_hd = bdrv_open_inherit(backing_filename, reference, options, 0, bs,
-                                   &child_backing, 0, errp);
+                                   &child_of_bds, bdrv_backing_role(bs), errp);
     if (!backing_hd) {
         bs->open_flags |= BDRV_O_NO_BACKING;
         error_prepend(errp, "Could not open backing file: ");
@@ -3895,8 +3909,8 @@ int bdrv_reopen_multiple(BlockReopenQueue *bs_queue, Error **errp)
         if (state->replace_backing_bs && state->new_backing_bs) {
             uint64_t nperm, nshared;
             bdrv_child_perm(state->bs, state->new_backing_bs,
-                            NULL, &child_backing, 0, bs_queue,
-                            state->perm, state->shared_perm,
+                            NULL, &child_of_bds, bdrv_backing_role(state->bs),
+                            bs_queue, state->perm, state->shared_perm,
                             &nperm, &nshared);
             ret = bdrv_check_update_perm(state->new_backing_bs, NULL,
                                          nperm, nshared, NULL, NULL, errp);
@@ -6852,7 +6866,7 @@ void bdrv_refresh_filename(BlockDriverState *bs)
         drv->bdrv_gather_child_options(bs, opts, backing_overridden);
     } else {
         QLIST_FOREACH(child, &bs->children, next) {
-            if (child->klass == &child_backing && !backing_overridden) {
+            if (child == bs->backing && !backing_overridden) {
                 /* We can skip the backing BDS if it has not been overridden */
                 continue;
             }
diff --git a/block/backup-top.c b/block/backup-top.c
index e2b4d2acd3..f059617095 100644
--- a/block/backup-top.c
+++ b/block/backup-top.c
@@ -143,7 +143,7 @@ static void backup_top_child_perm(BlockDriverState *bs, BdrvChild *c,
         return;
     }
 
-    if (child_class == &child_file) {
+    if (!(role & BDRV_CHILD_FILTERED)) {
         /*
          * Target child
          *
diff --git a/block/vvfat.c b/block/vvfat.c
index b4c8417dbd..e8848a0497 100644
--- a/block/vvfat.c
+++ b/block/vvfat.c
@@ -3219,7 +3219,8 @@ static void vvfat_child_perm(BlockDriverState *bs, BdrvChild *c,
 {
     BDRVVVFATState *s = bs->opaque;
 
-    assert(c == s->qcow || child_class == &child_backing);
+    assert(c == s->qcow ||
+           (child_class == &child_of_bds && (role & BDRV_CHILD_COW)));
 
     if (c == s->qcow) {
         /* This is a private node, nobody should try to attach to it */
diff --git a/tests/test-bdrv-drain.c b/tests/test-bdrv-drain.c
index b3d7960bd0..15393a0140 100644
--- a/tests/test-bdrv-drain.c
+++ b/tests/test-bdrv-drain.c
@@ -96,7 +96,7 @@ static void bdrv_test_child_perm(BlockDriverState *bs, BdrvChild *c,
      * bdrv_format_default_perms() accepts only these two, so disguise
      * detach_by_driver_cb_parent as one of them.
      */
-    if (child_class != &child_file && child_class != &child_backing) {
+    if (child_class != &child_file && child_class != &child_of_bds) {
         child_class = &child_file;
     }
 
@@ -1399,8 +1399,8 @@ static void test_detach_indirect(bool by_parent_cb)
     bdrv_ref(a);
     child_b = bdrv_attach_child(parent_b, b, "PB-B", &child_file, 0,
                                 &error_abort);
-    child_a = bdrv_attach_child(parent_b, a, "PB-A", &child_backing, 0,
-                                &error_abort);
+    child_a = bdrv_attach_child(parent_b, a, "PB-A", &child_of_bds,
+                                BDRV_CHILD_COW, &error_abort);
 
     bdrv_ref(a);
     bdrv_attach_child(parent_a, a, "PA-A",
@@ -1793,7 +1793,7 @@ static void test_drop_intermediate_poll(void)
     int i;
     int ret;
 
-    chain_child_class = child_backing;
+    chain_child_class = child_of_bds;
     chain_child_class.update_filename = drop_intermediate_poll_update_filename;
 
     for (i = 0; i < 3; i++) {
@@ -1816,7 +1816,7 @@ static void test_drop_intermediate_poll(void)
             /* Takes the reference to chain[i - 1] */
             chain[i]->backing = bdrv_attach_child(chain[i], chain[i - 1],
                                                   "chain", &chain_child_class,
-                                                  0, &error_abort);
+                                                  BDRV_CHILD_COW, &error_abort);
         }
     }
 
@@ -2034,7 +2034,8 @@ static void do_test_replace_child_mid_drain(int old_drain_count,
 
     bdrv_ref(old_child_bs);
     parent_bs->backing = bdrv_attach_child(parent_bs, old_child_bs, "child",
-                                           &child_backing, 0, &error_abort);
+                                           &child_of_bds, BDRV_CHILD_COW,
+                                           &error_abort);
 
     for (i = 0; i < old_drain_count; i++) {
         bdrv_drained_begin(old_child_bs);
-- 
2.26.2



^ permalink raw reply related	[flat|nested] 54+ messages in thread

* [PATCH v4 24/34] block: Drop child_backing
  2020-05-13 11:05 [PATCH v4 00/34] block: Introduce real BdrvChildRole Max Reitz
                   ` (22 preceding siblings ...)
  2020-05-13 11:05 ` [PATCH v4 23/34] block: Make backing files child_of_bds children Max Reitz
@ 2020-05-13 11:05 ` Max Reitz
  2020-05-13 20:47   ` Eric Blake
  2020-05-13 11:05 ` [PATCH v4 25/34] block: Make format drivers use child_of_bds Max Reitz
                   ` (11 subsequent siblings)
  35 siblings, 1 reply; 54+ messages in thread
From: Max Reitz @ 2020-05-13 11:05 UTC (permalink / raw)
  To: qemu-block; +Cc: Kevin Wolf, qemu-devel, Max Reitz

Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 include/block/block_int.h |  1 -
 block.c                   | 60 ++-------------------------------------
 2 files changed, 3 insertions(+), 58 deletions(-)

diff --git a/include/block/block_int.h b/include/block/block_int.h
index 4b09fa1124..0781d43af5 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -742,7 +742,6 @@ struct BdrvChildClass {
 
 extern const BdrvChildClass child_of_bds;
 extern const BdrvChildClass child_file;
-extern const BdrvChildClass child_backing;
 
 struct BdrvChild {
     BlockDriverState *bs;
diff --git a/block.c b/block.c
index 131ae20ffc..d138a3c261 100644
--- a/block.c
+++ b/block.c
@@ -1215,15 +1215,6 @@ static void bdrv_backing_attach(BdrvChild *c)
                     parent->backing_blocker);
 }
 
-/* XXX: Will be removed along with child_backing */
-static void bdrv_child_cb_attach_backing(BdrvChild *c)
-{
-    if (!(c->role & BDRV_CHILD_COW)) {
-        bdrv_backing_attach(c);
-    }
-    bdrv_child_cb_attach(c);
-}
-
 static void bdrv_backing_detach(BdrvChild *c)
 {
     BlockDriverState *parent = c->opaque;
@@ -1234,28 +1225,6 @@ static void bdrv_backing_detach(BdrvChild *c)
     parent->backing_blocker = NULL;
 }
 
-/* XXX: Will be removed along with child_backing */
-static void bdrv_child_cb_detach_backing(BdrvChild *c)
-{
-    if (!(c->role & BDRV_CHILD_COW)) {
-        bdrv_backing_detach(c);
-    }
-    bdrv_child_cb_detach(c);
-}
-
-/*
- * Returns the options and flags that bs->backing should get, based on the
- * given options and flags for the parent BDS
- */
-static void bdrv_backing_options(BdrvChildRole role, bool parent_is_format,
-                                 int *child_flags, QDict *child_options,
-                                 int parent_flags, QDict *parent_options)
-{
-    bdrv_inherited_options(BDRV_CHILD_COW, true,
-                           child_flags, child_options,
-                           parent_flags, parent_options);
-}
-
 static int bdrv_backing_update_filename(BdrvChild *c, BlockDriverState *base,
                                         const char *filename, Error **errp)
 {
@@ -1283,21 +1252,6 @@ static int bdrv_backing_update_filename(BdrvChild *c, BlockDriverState *base,
     return ret;
 }
 
-const BdrvChildClass child_backing = {
-    .parent_is_bds   = true,
-    .get_parent_desc = bdrv_child_get_parent_desc,
-    .attach          = bdrv_child_cb_attach_backing,
-    .detach          = bdrv_child_cb_detach_backing,
-    .inherit_options = bdrv_backing_options,
-    .drained_begin   = bdrv_child_cb_drained_begin,
-    .drained_poll    = bdrv_child_cb_drained_poll,
-    .drained_end     = bdrv_child_cb_drained_end,
-    .inactivate      = bdrv_child_cb_inactivate,
-    .update_filename = bdrv_backing_update_filename,
-    .can_set_aio_ctx = bdrv_child_cb_can_set_aio_ctx,
-    .set_aio_ctx     = bdrv_child_cb_set_aio_ctx,
-};
-
 /*
  * Returns the options and flags that a generic child of a BDS should
  * get, based on the given options and flags for the parent BDS.
@@ -2446,8 +2400,7 @@ static void bdrv_default_perms_for_cow(BlockDriverState *bs, BdrvChild *c,
                                        uint64_t perm, uint64_t shared,
                                        uint64_t *nperm, uint64_t *nshared)
 {
-    assert(child_class == &child_backing ||
-           (child_class == &child_of_bds && (role & BDRV_CHILD_COW)));
+    assert(child_class == &child_of_bds && (role & BDRV_CHILD_COW));
 
     /*
      * We want consistent read from backing files if the parent needs it.
@@ -2566,23 +2519,16 @@ void bdrv_format_default_perms(BlockDriverState *bs, BdrvChild *c,
                                uint64_t perm, uint64_t shared,
                                uint64_t *nperm, uint64_t *nshared)
 {
-    bool backing = (child_class == &child_backing);
-
     if (child_class == &child_of_bds) {
         bdrv_default_perms(bs, c, child_class, role, reopen_queue,
                            perm, shared, nperm, nshared);
         return;
     }
 
-    assert(child_class == &child_backing || child_class == &child_file);
+    assert(child_class == &child_file);
 
-    if (!backing) {
-        bdrv_default_perms_for_storage(bs, c, child_class, role, reopen_queue,
-                                       perm, shared, nperm, nshared);
-    } else {
-        bdrv_default_perms_for_cow(bs, c, child_class, role, reopen_queue,
+    bdrv_default_perms_for_storage(bs, c, child_class, role, reopen_queue,
                                    perm, shared, nperm, nshared);
-    }
 }
 
 void bdrv_default_perms(BlockDriverState *bs, BdrvChild *c,
-- 
2.26.2



^ permalink raw reply related	[flat|nested] 54+ messages in thread

* [PATCH v4 25/34] block: Make format drivers use child_of_bds
  2020-05-13 11:05 [PATCH v4 00/34] block: Introduce real BdrvChildRole Max Reitz
                   ` (23 preceding siblings ...)
  2020-05-13 11:05 ` [PATCH v4 24/34] block: Drop child_backing Max Reitz
@ 2020-05-13 11:05 ` Max Reitz
  2020-05-13 11:05 ` [PATCH v4 26/34] block: Make filter " Max Reitz
                   ` (10 subsequent siblings)
  35 siblings, 0 replies; 54+ messages in thread
From: Max Reitz @ 2020-05-13 11:05 UTC (permalink / raw)
  To: qemu-block; +Cc: Kevin Wolf, qemu-devel, Max Reitz

Commonly, they need to pass the BDRV_CHILD_IMAGE set as the
BdrvChildRole; but there are exceptions for drivers with external data
files (qcow2 and vmdk).

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
 block/bochs.c     |  4 ++--
 block/cloop.c     |  4 ++--
 block/crypto.c    |  4 ++--
 block/dmg.c       |  4 ++--
 block/parallels.c |  4 ++--
 block/qcow.c      |  4 ++--
 block/qcow2.c     | 19 +++++++++++++------
 block/qed.c       |  4 ++--
 block/vdi.c       |  4 ++--
 block/vhdx.c      |  4 ++--
 block/vmdk.c      | 20 +++++++++++++++++---
 block/vpc.c       |  4 ++--
 12 files changed, 50 insertions(+), 29 deletions(-)

diff --git a/block/bochs.c b/block/bochs.c
index b013e73063..62c3f42548 100644
--- a/block/bochs.c
+++ b/block/bochs.c
@@ -110,8 +110,8 @@ static int bochs_open(BlockDriverState *bs, QDict *options, int flags,
         return ret;
     }
 
-    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 0,
-                               false, errp);
+    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_of_bds,
+                               BDRV_CHILD_IMAGE, false, errp);
     if (!bs->file) {
         return -EINVAL;
     }
diff --git a/block/cloop.c b/block/cloop.c
index 3ed9fa63cc..d374a8427d 100644
--- a/block/cloop.c
+++ b/block/cloop.c
@@ -71,8 +71,8 @@ static int cloop_open(BlockDriverState *bs, QDict *options, int flags,
         return ret;
     }
 
-    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 0,
-                               false, errp);
+    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_of_bds,
+                               BDRV_CHILD_IMAGE, false, errp);
     if (!bs->file) {
         return -EINVAL;
     }
diff --git a/block/crypto.c b/block/crypto.c
index 8b516bfee2..457f3a06a5 100644
--- a/block/crypto.c
+++ b/block/crypto.c
@@ -218,8 +218,8 @@ static int block_crypto_open_generic(QCryptoBlockFormat format,
     unsigned int cflags = 0;
     QDict *cryptoopts = NULL;
 
-    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 0,
-                               false, errp);
+    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_of_bds,
+                               BDRV_CHILD_IMAGE, false, errp);
     if (!bs->file) {
         return -EINVAL;
     }
diff --git a/block/dmg.c b/block/dmg.c
index af8188638c..bc64194577 100644
--- a/block/dmg.c
+++ b/block/dmg.c
@@ -439,8 +439,8 @@ static int dmg_open(BlockDriverState *bs, QDict *options, int flags,
         return ret;
     }
 
-    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 0,
-                               false, errp);
+    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_of_bds,
+                               BDRV_CHILD_IMAGE, false, errp);
     if (!bs->file) {
         return -EINVAL;
     }
diff --git a/block/parallels.c b/block/parallels.c
index 9855ac1162..168d6c531a 100644
--- a/block/parallels.c
+++ b/block/parallels.c
@@ -739,8 +739,8 @@ static int parallels_open(BlockDriverState *bs, QDict *options, int flags,
     Error *local_err = NULL;
     char *buf;
 
-    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 0,
-                               false, errp);
+    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_of_bds,
+                               BDRV_CHILD_IMAGE, false, errp);
     if (!bs->file) {
         return -EINVAL;
     }
diff --git a/block/qcow.c b/block/qcow.c
index 13583f0339..5347037720 100644
--- a/block/qcow.c
+++ b/block/qcow.c
@@ -130,8 +130,8 @@ static int qcow_open(BlockDriverState *bs, QDict *options, int flags,
     qdict_extract_subqdict(options, &encryptopts, "encrypt.");
     encryptfmt = qdict_get_try_str(encryptopts, "format");
 
-    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 0,
-                               false, errp);
+    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_of_bds,
+                               BDRV_CHILD_IMAGE, false, errp);
     if (!bs->file) {
         ret = -EINVAL;
         goto fail;
diff --git a/block/qcow2.c b/block/qcow2.c
index 86335d9403..8d7230dca8 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -1590,8 +1590,9 @@ static int coroutine_fn qcow2_do_open(BlockDriverState *bs, QDict *options,
     }
 
     /* Open external data file */
-    s->data_file = bdrv_open_child(NULL, options, "data-file", bs, &child_file,
-                                   0, true, &local_err);
+    s->data_file = bdrv_open_child(NULL, options, "data-file", bs,
+                                   &child_of_bds, BDRV_CHILD_DATA,
+                                   true, &local_err);
     if (local_err) {
         error_propagate(errp, local_err);
         ret = -EINVAL;
@@ -1601,8 +1602,8 @@ static int coroutine_fn qcow2_do_open(BlockDriverState *bs, QDict *options,
     if (s->incompatible_features & QCOW2_INCOMPAT_DATA_FILE) {
         if (!s->data_file && s->image_data_file) {
             s->data_file = bdrv_open_child(s->image_data_file, options,
-                                           "data-file", bs, &child_file, 0,
-                                           false, errp);
+                                           "data-file", bs, &child_of_bds,
+                                           BDRV_CHILD_DATA, false, errp);
             if (!s->data_file) {
                 ret = -EINVAL;
                 goto fail;
@@ -1613,6 +1614,12 @@ static int coroutine_fn qcow2_do_open(BlockDriverState *bs, QDict *options,
             ret = -EINVAL;
             goto fail;
         }
+
+        /* No data here */
+        bs->file->role &= ~BDRV_CHILD_DATA;
+
+        /* Must succeed because we have given up permissions if anything */
+        bdrv_child_refresh_perms(bs, bs->file, &error_abort);
     } else {
         if (s->data_file) {
             error_setg(errp, "'data-file' can only be set for images with an "
@@ -1863,8 +1870,8 @@ static int qcow2_open(BlockDriverState *bs, QDict *options, int flags,
         .ret = -EINPROGRESS
     };
 
-    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 0,
-                               false, errp);
+    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_of_bds,
+                               BDRV_CHILD_IMAGE, false, errp);
     if (!bs->file) {
         return -EINVAL;
     }
diff --git a/block/qed.c b/block/qed.c
index 1ad2aba810..ef6463b48d 100644
--- a/block/qed.c
+++ b/block/qed.c
@@ -547,8 +547,8 @@ static int bdrv_qed_open(BlockDriverState *bs, QDict *options, int flags,
         .ret = -EINPROGRESS
     };
 
-    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 0,
-                               false, errp);
+    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_of_bds,
+                               BDRV_CHILD_IMAGE, false, errp);
     if (!bs->file) {
         return -EINVAL;
     }
diff --git a/block/vdi.c b/block/vdi.c
index 653acb5fc1..d20698b3cc 100644
--- a/block/vdi.c
+++ b/block/vdi.c
@@ -378,8 +378,8 @@ static int vdi_open(BlockDriverState *bs, QDict *options, int flags,
     Error *local_err = NULL;
     QemuUUID uuid_link, uuid_parent;
 
-    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 0,
-                               false, errp);
+    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_of_bds,
+                               BDRV_CHILD_IMAGE, false, errp);
     if (!bs->file) {
         return -EINVAL;
     }
diff --git a/block/vhdx.c b/block/vhdx.c
index dde156c97b..62c6bd69ff 100644
--- a/block/vhdx.c
+++ b/block/vhdx.c
@@ -996,8 +996,8 @@ static int vhdx_open(BlockDriverState *bs, QDict *options, int flags,
     uint64_t signature;
     Error *local_err = NULL;
 
-    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 0,
-                               false, errp);
+    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_of_bds,
+                               BDRV_CHILD_IMAGE, false, errp);
     if (!bs->file) {
         return -EINVAL;
     }
diff --git a/block/vmdk.c b/block/vmdk.c
index c2cb741e2d..fadc98a262 100644
--- a/block/vmdk.c
+++ b/block/vmdk.c
@@ -1089,6 +1089,7 @@ static int vmdk_parse_extents(const char *desc, BlockDriverState *bs,
     char *desc_file_dir = NULL;
     char *extent_path;
     BdrvChild *extent_file;
+    BdrvChildRole extent_role;
     BDRVVmdkState *s = bs->opaque;
     VmdkExtent *extent;
     char extent_opt_prefix[32];
@@ -1151,8 +1152,15 @@ static int vmdk_parse_extents(const char *desc, BlockDriverState *bs,
         ret = snprintf(extent_opt_prefix, 32, "extents.%d", s->num_extents);
         assert(ret < 32);
 
+        extent_role = BDRV_CHILD_DATA;
+        if (strcmp(type, "FLAT") != 0 && strcmp(type, "VMFS") != 0) {
+            /* non-flat extents have metadata */
+            extent_role |= BDRV_CHILD_METADATA;
+        }
+
         extent_file = bdrv_open_child(extent_path, options, extent_opt_prefix,
-                                      bs, &child_file, 0, false, &local_err);
+                                      bs, &child_of_bds, extent_role, false,
+                                      &local_err);
         g_free(extent_path);
         if (local_err) {
             error_propagate(errp, local_err);
@@ -1257,8 +1265,8 @@ static int vmdk_open(BlockDriverState *bs, QDict *options, int flags,
     uint32_t magic;
     Error *local_err = NULL;
 
-    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 0,
-                               false, errp);
+    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_of_bds,
+                               BDRV_CHILD_IMAGE, false, errp);
     if (!bs->file) {
         return -EINVAL;
     }
@@ -1277,6 +1285,12 @@ static int vmdk_open(BlockDriverState *bs, QDict *options, int flags,
             s->desc_offset = 0x200;
             break;
         default:
+            /* No data in the descriptor file */
+            bs->file->role &= ~BDRV_CHILD_DATA;
+
+            /* Must succeed because we have given up permissions if anything */
+            bdrv_child_refresh_perms(bs, bs->file, &error_abort);
+
             ret = vmdk_open_desc_file(bs, flags, buf, options, errp);
             break;
     }
diff --git a/block/vpc.c b/block/vpc.c
index b2a86074a5..651a6737b6 100644
--- a/block/vpc.c
+++ b/block/vpc.c
@@ -228,8 +228,8 @@ static int vpc_open(BlockDriverState *bs, QDict *options, int flags,
     int ret;
     int64_t bs_size;
 
-    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 0,
-                               false, errp);
+    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_of_bds,
+                               BDRV_CHILD_IMAGE, false, errp);
     if (!bs->file) {
         return -EINVAL;
     }
-- 
2.26.2



^ permalink raw reply related	[flat|nested] 54+ messages in thread

* [PATCH v4 26/34] block: Make filter drivers use child_of_bds
  2020-05-13 11:05 [PATCH v4 00/34] block: Introduce real BdrvChildRole Max Reitz
                   ` (24 preceding siblings ...)
  2020-05-13 11:05 ` [PATCH v4 25/34] block: Make format drivers use child_of_bds Max Reitz
@ 2020-05-13 11:05 ` Max Reitz
  2020-05-13 21:02   ` Eric Blake
  2020-05-13 11:05 ` [PATCH v4 27/34] block: Use child_of_bds in remaining places Max Reitz
                   ` (9 subsequent siblings)
  35 siblings, 1 reply; 54+ messages in thread
From: Max Reitz @ 2020-05-13 11:05 UTC (permalink / raw)
  To: qemu-block; +Cc: Kevin Wolf, qemu-devel, Max Reitz

Note that some filters have secondary children, namely blkverify (the
image to be verified) and blklogwrites (the log).  This patch does not
touch those children.

Note that for blkverify, the filtered child should not be format-probed.
While there is nothing enforcing this here, in practice, it will not be:
blkverify implements .bdrv_file_open.  The block layer ensures (and in
fact, asserts) that BDRV_O_PROTOCOL is set for every BDS whose driver
implements .bdrv_file_open.  This flag will then be bequeathed to
blkverify's children, and they will thus (by default) not be probed
either.

("By default" refers to the fact that blkverify's other child (the
non-filtered one) will have BDRV_O_PROTOCOL force-unset, because that is
what happens for all non-filtered children of non-format drivers.)

Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 block/blkdebug.c        | 4 +++-
 block/blklogwrites.c    | 3 ++-
 block/blkreplay.c       | 5 +++--
 block/blkverify.c       | 4 +++-
 block/copy-on-read.c    | 5 +++--
 block/filter-compress.c | 5 +++--
 block/replication.c     | 3 ++-
 block/throttle.c        | 5 +++--
 8 files changed, 22 insertions(+), 12 deletions(-)

diff --git a/block/blkdebug.c b/block/blkdebug.c
index 8dd8ed6055..b31fa40b0e 100644
--- a/block/blkdebug.c
+++ b/block/blkdebug.c
@@ -497,7 +497,9 @@ static int blkdebug_open(BlockDriverState *bs, QDict *options, int flags,
 
     /* Open the image file */
     bs->file = bdrv_open_child(qemu_opt_get(opts, "x-image"), options, "image",
-                               bs, &child_file, 0, false, &local_err);
+                               bs, &child_of_bds,
+                               BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY,
+                               false, &local_err);
     if (local_err) {
         ret = -EINVAL;
         error_propagate(errp, local_err);
diff --git a/block/blklogwrites.c b/block/blklogwrites.c
index 4faf912ef1..78b0c49460 100644
--- a/block/blklogwrites.c
+++ b/block/blklogwrites.c
@@ -157,7 +157,8 @@ static int blk_log_writes_open(BlockDriverState *bs, QDict *options, int flags,
     }
 
     /* Open the file */
-    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 0, false,
+    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_of_bds,
+                               BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY, false,
                                &local_err);
     if (local_err) {
         ret = -EINVAL;
diff --git a/block/blkreplay.c b/block/blkreplay.c
index 9b2814fc58..20d6139baa 100644
--- a/block/blkreplay.c
+++ b/block/blkreplay.c
@@ -27,8 +27,9 @@ static int blkreplay_open(BlockDriverState *bs, QDict *options, int flags,
     int ret;
 
     /* Open the image file */
-    bs->file = bdrv_open_child(NULL, options, "image",
-                               bs, &child_file, 0, false, &local_err);
+    bs->file = bdrv_open_child(NULL, options, "image", bs, &child_of_bds,
+                               BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY,
+                               false, &local_err);
     if (local_err) {
         ret = -EINVAL;
         error_propagate(errp, local_err);
diff --git a/block/blkverify.c b/block/blkverify.c
index 1684b7aa2e..5c3b29244a 100644
--- a/block/blkverify.c
+++ b/block/blkverify.c
@@ -125,7 +125,9 @@ static int blkverify_open(BlockDriverState *bs, QDict *options, int flags,
 
     /* Open the raw file */
     bs->file = bdrv_open_child(qemu_opt_get(opts, "x-raw"), options, "raw",
-                               bs, &child_file, 0, false, &local_err);
+                               bs, &child_of_bds,
+                               BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY,
+                               false, &local_err);
     if (local_err) {
         ret = -EINVAL;
         error_propagate(errp, local_err);
diff --git a/block/copy-on-read.c b/block/copy-on-read.c
index a2d92ac394..c857ea0da7 100644
--- a/block/copy-on-read.c
+++ b/block/copy-on-read.c
@@ -28,8 +28,9 @@
 static int cor_open(BlockDriverState *bs, QDict *options, int flags,
                     Error **errp)
 {
-    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 0, false,
-                               errp);
+    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_of_bds,
+                               BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY,
+                               false, errp);
     if (!bs->file) {
         return -EINVAL;
     }
diff --git a/block/filter-compress.c b/block/filter-compress.c
index 4dc5f9fb8c..9edd937645 100644
--- a/block/filter-compress.c
+++ b/block/filter-compress.c
@@ -30,8 +30,9 @@
 static int compress_open(BlockDriverState *bs, QDict *options, int flags,
                          Error **errp)
 {
-    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 0, false,
-                               errp);
+    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_of_bds,
+                               BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY,
+                               false, errp);
     if (!bs->file) {
         return -EINVAL;
     }
diff --git a/block/replication.c b/block/replication.c
index 61119ed36c..ca78eb6785 100644
--- a/block/replication.c
+++ b/block/replication.c
@@ -90,7 +90,8 @@ static int replication_open(BlockDriverState *bs, QDict *options,
     const char *mode;
     const char *top_id;
 
-    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 0,
+    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_of_bds,
+                               BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY,
                                false, errp);
     if (!bs->file) {
         return -EINVAL;
diff --git a/block/throttle.c b/block/throttle.c
index 2dea913be7..47b0a3522d 100644
--- a/block/throttle.c
+++ b/block/throttle.c
@@ -81,8 +81,9 @@ static int throttle_open(BlockDriverState *bs, QDict *options,
     char *group;
     int ret;
 
-    bs->file = bdrv_open_child(NULL, options, "file", bs,
-                               &child_file, 0, false, errp);
+    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_of_bds,
+                               BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY,
+                               false, errp);
     if (!bs->file) {
         return -EINVAL;
     }
-- 
2.26.2



^ permalink raw reply related	[flat|nested] 54+ messages in thread

* [PATCH v4 27/34] block: Use child_of_bds in remaining places
  2020-05-13 11:05 [PATCH v4 00/34] block: Introduce real BdrvChildRole Max Reitz
                   ` (25 preceding siblings ...)
  2020-05-13 11:05 ` [PATCH v4 26/34] block: Make filter " Max Reitz
@ 2020-05-13 11:05 ` Max Reitz
  2020-05-13 21:08   ` Eric Blake
  2020-05-13 11:05 ` [PATCH v4 28/34] tests: Use child_of_bds instead of child_file Max Reitz
                   ` (8 subsequent siblings)
  35 siblings, 1 reply; 54+ messages in thread
From: Max Reitz @ 2020-05-13 11:05 UTC (permalink / raw)
  To: qemu-block; +Cc: Kevin Wolf, qemu-devel, Max Reitz

Replace child_file by child_of_bds in all remaining places (excluding
tests).

Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 block.c              |  3 ++-
 block/backup-top.c   |  4 ++--
 block/blklogwrites.c |  4 ++--
 block/raw-format.c   | 15 +++++++++++++--
 4 files changed, 19 insertions(+), 7 deletions(-)

diff --git a/block.c b/block.c
index d138a3c261..fb94adcca4 100644
--- a/block.c
+++ b/block.c
@@ -3406,7 +3406,8 @@ static BlockDriverState *bdrv_open_inherit(const char *filename,
         BlockDriverState *file_bs;
 
         file_bs = bdrv_open_child_bs(filename, options, "file", bs,
-                                     &child_file, 0, true, &local_err);
+                                     &child_of_bds, BDRV_CHILD_IMAGE,
+                                     true, &local_err);
         if (local_err) {
             goto fail;
         }
diff --git a/block/backup-top.c b/block/backup-top.c
index f059617095..8af2c5fe9b 100644
--- a/block/backup-top.c
+++ b/block/backup-top.c
@@ -215,8 +215,8 @@ BlockDriverState *bdrv_backup_top_append(BlockDriverState *source,
              source->supported_zero_flags);
 
     bdrv_ref(target);
-    state->target = bdrv_attach_child(top, target, "target", &child_file, 0,
-                                      errp);
+    state->target = bdrv_attach_child(top, target, "target", &child_of_bds,
+                                      BDRV_CHILD_DATA, errp);
     if (!state->target) {
         bdrv_unref(target);
         bdrv_unref(top);
diff --git a/block/blklogwrites.c b/block/blklogwrites.c
index 78b0c49460..3a57b273fc 100644
--- a/block/blklogwrites.c
+++ b/block/blklogwrites.c
@@ -167,8 +167,8 @@ static int blk_log_writes_open(BlockDriverState *bs, QDict *options, int flags,
     }
 
     /* Open the log file */
-    s->log_file = bdrv_open_child(NULL, options, "log", bs, &child_file, 0,
-                                  false, &local_err);
+    s->log_file = bdrv_open_child(NULL, options, "log", bs, &child_of_bds,
+                                  BDRV_CHILD_METADATA, false, &local_err);
     if (local_err) {
         ret = -EINVAL;
         error_propagate(errp, local_err);
diff --git a/block/raw-format.c b/block/raw-format.c
index 824fe70686..bfb4d7ddb7 100644
--- a/block/raw-format.c
+++ b/block/raw-format.c
@@ -441,6 +441,7 @@ static int raw_open(BlockDriverState *bs, QDict *options, int flags,
     BDRVRawState *s = bs->opaque;
     bool has_size;
     uint64_t offset, size;
+    BdrvChildRole file_role;
     int ret;
 
     ret = raw_read_options(options, &offset, &has_size, &size, errp);
@@ -448,8 +449,18 @@ static int raw_open(BlockDriverState *bs, QDict *options, int flags,
         return ret;
     }
 
-    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 0,
-                               false, errp);
+    /*
+     * Without offset and a size limit, this driver behaves very much
+     * like a filter.  With any such limit, it does not.
+     */
+    if (offset || has_size) {
+        file_role = BDRV_CHILD_DATA | BDRV_CHILD_PRIMARY;
+    } else {
+        file_role = BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY;
+    }
+
+    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_of_bds,
+                               file_role, false, errp);
     if (!bs->file) {
         return -EINVAL;
     }
-- 
2.26.2



^ permalink raw reply related	[flat|nested] 54+ messages in thread

* [PATCH v4 28/34] tests: Use child_of_bds instead of child_file
  2020-05-13 11:05 [PATCH v4 00/34] block: Introduce real BdrvChildRole Max Reitz
                   ` (26 preceding siblings ...)
  2020-05-13 11:05 ` [PATCH v4 27/34] block: Use child_of_bds in remaining places Max Reitz
@ 2020-05-13 11:05 ` Max Reitz
  2020-05-13 11:05 ` [PATCH v4 29/34] block: Use bdrv_default_perms() Max Reitz
                   ` (7 subsequent siblings)
  35 siblings, 0 replies; 54+ messages in thread
From: Max Reitz @ 2020-05-13 11:05 UTC (permalink / raw)
  To: qemu-block; +Cc: Kevin Wolf, qemu-devel, Max Reitz

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
 tests/test-bdrv-drain.c     | 29 +++++++++++++++++------------
 tests/test-bdrv-graph-mod.c |  6 ++++--
 2 files changed, 21 insertions(+), 14 deletions(-)

diff --git a/tests/test-bdrv-drain.c b/tests/test-bdrv-drain.c
index 15393a0140..91567ca97d 100644
--- a/tests/test-bdrv-drain.c
+++ b/tests/test-bdrv-drain.c
@@ -97,7 +97,7 @@ static void bdrv_test_child_perm(BlockDriverState *bs, BdrvChild *c,
      * detach_by_driver_cb_parent as one of them.
      */
     if (child_class != &child_file && child_class != &child_of_bds) {
-        child_class = &child_file;
+        child_class = &child_of_bds;
     }
 
     bdrv_format_default_perms(bs, c, child_class, role, reopen_queue,
@@ -1203,7 +1203,8 @@ static void do_test_delete_by_drain(bool detach_instead_of_delete,
 
     null_bs = bdrv_open("null-co://", NULL, NULL, BDRV_O_RDWR | BDRV_O_PROTOCOL,
                         &error_abort);
-    bdrv_attach_child(bs, null_bs, "null-child", &child_file, 0, &error_abort);
+    bdrv_attach_child(bs, null_bs, "null-child", &child_of_bds,
+                      BDRV_CHILD_DATA, &error_abort);
 
     /* This child will be the one to pass to requests through to, and
      * it will stall until a drain occurs */
@@ -1211,14 +1212,17 @@ static void do_test_delete_by_drain(bool detach_instead_of_delete,
                                     &error_abort);
     child_bs->total_sectors = 65536 >> BDRV_SECTOR_BITS;
     /* Takes our reference to child_bs */
-    tts->wait_child = bdrv_attach_child(bs, child_bs, "wait-child", &child_file,
-                                        0, &error_abort);
+    tts->wait_child = bdrv_attach_child(bs, child_bs, "wait-child",
+                                        &child_of_bds,
+                                        BDRV_CHILD_DATA | BDRV_CHILD_PRIMARY,
+                                        &error_abort);
 
     /* This child is just there to be deleted
      * (for detach_instead_of_delete == true) */
     null_bs = bdrv_open("null-co://", NULL, NULL, BDRV_O_RDWR | BDRV_O_PROTOCOL,
                         &error_abort);
-    bdrv_attach_child(bs, null_bs, "null-child", &child_file, 0, &error_abort);
+    bdrv_attach_child(bs, null_bs, "null-child", &child_of_bds, BDRV_CHILD_DATA,
+                      &error_abort);
 
     blk = blk_new(qemu_get_aio_context(), BLK_PERM_ALL, BLK_PERM_ALL);
     blk_insert_bs(blk, bs, &error_abort);
@@ -1315,7 +1319,8 @@ static void detach_indirect_bh(void *opaque)
 
     bdrv_ref(data->c);
     data->child_c = bdrv_attach_child(data->parent_b, data->c, "PB-C",
-                                      &child_file, 0, &error_abort);
+                                      &child_of_bds, BDRV_CHILD_DATA,
+                                      &error_abort);
 }
 
 static void detach_by_parent_aio_cb(void *opaque, int ret)
@@ -1332,7 +1337,7 @@ static void detach_by_driver_cb_drained_begin(BdrvChild *child)
 {
     aio_bh_schedule_oneshot(qemu_get_current_aio_context(),
                             detach_indirect_bh, &detach_by_parent_data);
-    child_file.drained_begin(child);
+    child_of_bds.drained_begin(child);
 }
 
 static BdrvChildClass detach_by_driver_cb_class;
@@ -1367,7 +1372,7 @@ static void test_detach_indirect(bool by_parent_cb)
     QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, NULL, 0);
 
     if (!by_parent_cb) {
-        detach_by_driver_cb_class = child_file;
+        detach_by_driver_cb_class = child_of_bds;
         detach_by_driver_cb_class.drained_begin =
             detach_by_driver_cb_drained_begin;
     }
@@ -1397,15 +1402,15 @@ static void test_detach_indirect(bool by_parent_cb)
     /* Set child relationships */
     bdrv_ref(b);
     bdrv_ref(a);
-    child_b = bdrv_attach_child(parent_b, b, "PB-B", &child_file, 0,
-                                &error_abort);
+    child_b = bdrv_attach_child(parent_b, b, "PB-B", &child_of_bds,
+                                BDRV_CHILD_DATA, &error_abort);
     child_a = bdrv_attach_child(parent_b, a, "PB-A", &child_of_bds,
                                 BDRV_CHILD_COW, &error_abort);
 
     bdrv_ref(a);
     bdrv_attach_child(parent_a, a, "PA-A",
-                      by_parent_cb ? &child_file : &detach_by_driver_cb_class,
-                      0, &error_abort);
+                      by_parent_cb ? &child_of_bds : &detach_by_driver_cb_class,
+                      BDRV_CHILD_DATA, &error_abort);
 
     g_assert_cmpint(parent_a->refcnt, ==, 1);
     g_assert_cmpint(parent_b->refcnt, ==, 1);
diff --git a/tests/test-bdrv-graph-mod.c b/tests/test-bdrv-graph-mod.c
index 3707e2533c..6ae91ff171 100644
--- a/tests/test-bdrv-graph-mod.c
+++ b/tests/test-bdrv-graph-mod.c
@@ -112,7 +112,8 @@ static void test_update_perm_tree(void)
 
     blk_insert_bs(root, bs, &error_abort);
 
-    bdrv_attach_child(filter, bs, "child", &child_file, 0, &error_abort);
+    bdrv_attach_child(filter, bs, "child", &child_of_bds,
+                      BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY, &error_abort);
 
     bdrv_append(filter, bs, &local_err);
 
@@ -178,7 +179,8 @@ static void test_should_update_child(void)
     bdrv_set_backing_hd(target, bs, &error_abort);
 
     g_assert(target->backing->bs == bs);
-    bdrv_attach_child(filter, target, "target", &child_file, 0, &error_abort);
+    bdrv_attach_child(filter, target, "target", &child_of_bds,
+                      BDRV_CHILD_DATA, &error_abort);
     bdrv_append(filter, bs, &error_abort);
     g_assert(target->backing->bs == bs);
 
-- 
2.26.2



^ permalink raw reply related	[flat|nested] 54+ messages in thread

* [PATCH v4 29/34] block: Use bdrv_default_perms()
  2020-05-13 11:05 [PATCH v4 00/34] block: Introduce real BdrvChildRole Max Reitz
                   ` (27 preceding siblings ...)
  2020-05-13 11:05 ` [PATCH v4 28/34] tests: Use child_of_bds instead of child_file Max Reitz
@ 2020-05-13 11:05 ` Max Reitz
  2020-05-13 11:05 ` [PATCH v4 30/34] block: Make bdrv_filter_default_perms() static Max Reitz
                   ` (6 subsequent siblings)
  35 siblings, 0 replies; 54+ messages in thread
From: Max Reitz @ 2020-05-13 11:05 UTC (permalink / raw)
  To: qemu-block; +Cc: Kevin Wolf, qemu-devel, Max Reitz

bdrv_default_perms() can decide which permission profile to use based on
the BdrvChildRole, so block drivers do not need to select it explicitly.

The blkverify driver now no longer shares the WRITE permission for the
image to verify.  We thus have to adjust two places in
test-block-iothread not to take it.  (Note that in theory, blkverify
should behave like quorum in this regard and share neither WRITE nor
RESIZE for both of its children.  In practice, it does not really
matter, because blkverify is used only for debugging, so we might as
well keep its permissions rather liberal.)

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
 block/backup-top.c          |  4 ++--
 block/blkdebug.c            |  4 ++--
 block/blklogwrites.c        |  9 ++-------
 block/blkreplay.c           |  2 +-
 block/blkverify.c           |  2 +-
 block/bochs.c               |  2 +-
 block/cloop.c               |  2 +-
 block/crypto.c              |  2 +-
 block/dmg.c                 |  2 +-
 block/filter-compress.c     |  2 +-
 block/parallels.c           |  2 +-
 block/qcow.c                |  2 +-
 block/qcow2.c               |  2 +-
 block/qed.c                 |  2 +-
 block/raw-format.c          |  2 +-
 block/throttle.c            |  2 +-
 block/vdi.c                 |  2 +-
 block/vhdx.c                |  2 +-
 block/vmdk.c                |  2 +-
 block/vpc.c                 |  2 +-
 tests/test-bdrv-drain.c     | 10 +++++-----
 tests/test-bdrv-graph-mod.c |  2 +-
 tests/test-block-iothread.c | 17 ++++++++++++++---
 23 files changed, 43 insertions(+), 37 deletions(-)

diff --git a/block/backup-top.c b/block/backup-top.c
index 8af2c5fe9b..f0efec18b5 100644
--- a/block/backup-top.c
+++ b/block/backup-top.c
@@ -156,8 +156,8 @@ static void backup_top_child_perm(BlockDriverState *bs, BdrvChild *c,
         *nperm = BLK_PERM_WRITE;
     } else {
         /* Source child */
-        bdrv_filter_default_perms(bs, c, child_class, role, reopen_queue,
-                                  perm, shared, nperm, nshared);
+        bdrv_default_perms(bs, c, child_class, role, reopen_queue,
+                           perm, shared, nperm, nshared);
 
         if (perm & BLK_PERM_WRITE) {
             *nperm = *nperm | BLK_PERM_CONSISTENT_READ;
diff --git a/block/blkdebug.c b/block/blkdebug.c
index b31fa40b0e..a925d8295e 100644
--- a/block/blkdebug.c
+++ b/block/blkdebug.c
@@ -1003,8 +1003,8 @@ static void blkdebug_child_perm(BlockDriverState *bs, BdrvChild *c,
 {
     BDRVBlkdebugState *s = bs->opaque;
 
-    bdrv_filter_default_perms(bs, c, child_class, role, reopen_queue,
-                              perm, shared, nperm, nshared);
+    bdrv_default_perms(bs, c, child_class, role, reopen_queue,
+                       perm, shared, nperm, nshared);
 
     *nperm |= s->take_child_perms;
     *nshared &= ~s->unshare_child_perms;
diff --git a/block/blklogwrites.c b/block/blklogwrites.c
index 3a57b273fc..8684fb1c74 100644
--- a/block/blklogwrites.c
+++ b/block/blklogwrites.c
@@ -295,13 +295,8 @@ static void blk_log_writes_child_perm(BlockDriverState *bs, BdrvChild *c,
         return;
     }
 
-    if (!strcmp(c->name, "log")) {
-        bdrv_format_default_perms(bs, c, child_class, role, ro_q, perm, shrd,
-                                  nperm, nshrd);
-    } else {
-        bdrv_filter_default_perms(bs, c, child_class, role, ro_q, perm, shrd,
-                                  nperm, nshrd);
-    }
+    bdrv_default_perms(bs, c, child_class, role, ro_q, perm, shrd,
+                       nperm, nshrd);
 }
 
 static void blk_log_writes_refresh_limits(BlockDriverState *bs, Error **errp)
diff --git a/block/blkreplay.c b/block/blkreplay.c
index 20d6139baa..30a0f5d57a 100644
--- a/block/blkreplay.c
+++ b/block/blkreplay.c
@@ -139,7 +139,7 @@ static BlockDriver bdrv_blkreplay = {
     .is_filter              = true,
 
     .bdrv_open              = blkreplay_open,
-    .bdrv_child_perm        = bdrv_filter_default_perms,
+    .bdrv_child_perm        = bdrv_default_perms,
     .bdrv_getlength         = blkreplay_getlength,
 
     .bdrv_co_preadv         = blkreplay_co_preadv,
diff --git a/block/blkverify.c b/block/blkverify.c
index 5c3b29244a..2f261de24b 100644
--- a/block/blkverify.c
+++ b/block/blkverify.c
@@ -319,7 +319,7 @@ static BlockDriver bdrv_blkverify = {
     .bdrv_parse_filename              = blkverify_parse_filename,
     .bdrv_file_open                   = blkverify_open,
     .bdrv_close                       = blkverify_close,
-    .bdrv_child_perm                  = bdrv_filter_default_perms,
+    .bdrv_child_perm                  = bdrv_default_perms,
     .bdrv_getlength                   = blkverify_getlength,
     .bdrv_refresh_filename            = blkverify_refresh_filename,
     .bdrv_dirname                     = blkverify_dirname,
diff --git a/block/bochs.c b/block/bochs.c
index 62c3f42548..2f010ab40a 100644
--- a/block/bochs.c
+++ b/block/bochs.c
@@ -297,7 +297,7 @@ static BlockDriver bdrv_bochs = {
     .instance_size	= sizeof(BDRVBochsState),
     .bdrv_probe		= bochs_probe,
     .bdrv_open		= bochs_open,
-    .bdrv_child_perm     = bdrv_format_default_perms,
+    .bdrv_child_perm     = bdrv_default_perms,
     .bdrv_refresh_limits = bochs_refresh_limits,
     .bdrv_co_preadv = bochs_co_preadv,
     .bdrv_close		= bochs_close,
diff --git a/block/cloop.c b/block/cloop.c
index d374a8427d..c99192a57f 100644
--- a/block/cloop.c
+++ b/block/cloop.c
@@ -293,7 +293,7 @@ static BlockDriver bdrv_cloop = {
     .instance_size  = sizeof(BDRVCloopState),
     .bdrv_probe     = cloop_probe,
     .bdrv_open      = cloop_open,
-    .bdrv_child_perm     = bdrv_format_default_perms,
+    .bdrv_child_perm     = bdrv_default_perms,
     .bdrv_refresh_limits = cloop_refresh_limits,
     .bdrv_co_preadv = cloop_co_preadv,
     .bdrv_close     = cloop_close,
diff --git a/block/crypto.c b/block/crypto.c
index 457f3a06a5..b216e12c31 100644
--- a/block/crypto.c
+++ b/block/crypto.c
@@ -756,7 +756,7 @@ static BlockDriver bdrv_crypto_luks = {
     .bdrv_close         = block_crypto_close,
     /* This driver doesn't modify LUKS metadata except when creating image.
      * Allow share-rw=on as a special case. */
-    .bdrv_child_perm    = bdrv_filter_default_perms,
+    .bdrv_child_perm    = bdrv_default_perms,
     .bdrv_co_create     = block_crypto_co_create_luks,
     .bdrv_co_create_opts = block_crypto_co_create_opts_luks,
     .bdrv_co_truncate   = block_crypto_co_truncate,
diff --git a/block/dmg.c b/block/dmg.c
index bc64194577..0d6c317296 100644
--- a/block/dmg.c
+++ b/block/dmg.c
@@ -750,7 +750,7 @@ static BlockDriver bdrv_dmg = {
     .bdrv_probe     = dmg_probe,
     .bdrv_open      = dmg_open,
     .bdrv_refresh_limits = dmg_refresh_limits,
-    .bdrv_child_perm     = bdrv_format_default_perms,
+    .bdrv_child_perm     = bdrv_default_perms,
     .bdrv_co_preadv = dmg_co_preadv,
     .bdrv_close     = dmg_close,
     .is_format      = true,
diff --git a/block/filter-compress.c b/block/filter-compress.c
index 9edd937645..8ec1991c1f 100644
--- a/block/filter-compress.c
+++ b/block/filter-compress.c
@@ -133,7 +133,7 @@ static BlockDriver bdrv_compress = {
     .format_name                        = "compress",
 
     .bdrv_open                          = compress_open,
-    .bdrv_child_perm                    = bdrv_filter_default_perms,
+    .bdrv_child_perm                    = bdrv_default_perms,
 
     .bdrv_getlength                     = compress_getlength,
 
diff --git a/block/parallels.c b/block/parallels.c
index 168d6c531a..63a1cde8af 100644
--- a/block/parallels.c
+++ b/block/parallels.c
@@ -912,7 +912,7 @@ static BlockDriver bdrv_parallels = {
     .bdrv_probe		= parallels_probe,
     .bdrv_open		= parallels_open,
     .bdrv_close		= parallels_close,
-    .bdrv_child_perm          = bdrv_format_default_perms,
+    .bdrv_child_perm          = bdrv_default_perms,
     .bdrv_co_block_status     = parallels_co_block_status,
     .bdrv_has_zero_init       = bdrv_has_zero_init_1,
     .bdrv_co_flush_to_os      = parallels_co_flush_to_os,
diff --git a/block/qcow.c b/block/qcow.c
index 5347037720..ee5d35fe20 100644
--- a/block/qcow.c
+++ b/block/qcow.c
@@ -1180,7 +1180,7 @@ static BlockDriver bdrv_qcow = {
     .bdrv_probe		= qcow_probe,
     .bdrv_open		= qcow_open,
     .bdrv_close		= qcow_close,
-    .bdrv_child_perm        = bdrv_format_default_perms,
+    .bdrv_child_perm        = bdrv_default_perms,
     .bdrv_reopen_prepare    = qcow_reopen_prepare,
     .bdrv_co_create         = qcow_co_create,
     .bdrv_co_create_opts    = qcow_co_create_opts,
diff --git a/block/qcow2.c b/block/qcow2.c
index 8d7230dca8..fe0ce39799 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -5744,7 +5744,7 @@ BlockDriver bdrv_qcow2 = {
     .bdrv_reopen_commit_post = qcow2_reopen_commit_post,
     .bdrv_reopen_abort    = qcow2_reopen_abort,
     .bdrv_join_options    = qcow2_join_options,
-    .bdrv_child_perm      = bdrv_format_default_perms,
+    .bdrv_child_perm      = bdrv_default_perms,
     .bdrv_co_create_opts  = qcow2_co_create_opts,
     .bdrv_co_create       = qcow2_co_create,
     .bdrv_has_zero_init   = qcow2_has_zero_init,
diff --git a/block/qed.c b/block/qed.c
index ef6463b48d..c0c65015c7 100644
--- a/block/qed.c
+++ b/block/qed.c
@@ -1672,7 +1672,7 @@ static BlockDriver bdrv_qed = {
     .bdrv_open                = bdrv_qed_open,
     .bdrv_close               = bdrv_qed_close,
     .bdrv_reopen_prepare      = bdrv_qed_reopen_prepare,
-    .bdrv_child_perm          = bdrv_format_default_perms,
+    .bdrv_child_perm          = bdrv_default_perms,
     .bdrv_co_create           = bdrv_qed_co_create,
     .bdrv_co_create_opts      = bdrv_qed_co_create_opts,
     .bdrv_has_zero_init       = bdrv_has_zero_init_1,
diff --git a/block/raw-format.c b/block/raw-format.c
index bfb4d7ddb7..018441bddf 100644
--- a/block/raw-format.c
+++ b/block/raw-format.c
@@ -586,7 +586,7 @@ BlockDriver bdrv_raw = {
     .bdrv_reopen_commit   = &raw_reopen_commit,
     .bdrv_reopen_abort    = &raw_reopen_abort,
     .bdrv_open            = &raw_open,
-    .bdrv_child_perm      = bdrv_filter_default_perms,
+    .bdrv_child_perm      = bdrv_default_perms,
     .bdrv_co_create_opts  = &raw_co_create_opts,
     .bdrv_co_preadv       = &raw_co_preadv,
     .bdrv_co_pwritev      = &raw_co_pwritev,
diff --git a/block/throttle.c b/block/throttle.c
index 47b0a3522d..0ebbad0743 100644
--- a/block/throttle.c
+++ b/block/throttle.c
@@ -237,7 +237,7 @@ static BlockDriver bdrv_throttle = {
     .bdrv_close                         =   throttle_close,
     .bdrv_co_flush                      =   throttle_co_flush,
 
-    .bdrv_child_perm                    =   bdrv_filter_default_perms,
+    .bdrv_child_perm                    =   bdrv_default_perms,
 
     .bdrv_getlength                     =   throttle_getlength,
 
diff --git a/block/vdi.c b/block/vdi.c
index d20698b3cc..2f506a01ba 100644
--- a/block/vdi.c
+++ b/block/vdi.c
@@ -1039,7 +1039,7 @@ static BlockDriver bdrv_vdi = {
     .bdrv_open = vdi_open,
     .bdrv_close = vdi_close,
     .bdrv_reopen_prepare = vdi_reopen_prepare,
-    .bdrv_child_perm          = bdrv_format_default_perms,
+    .bdrv_child_perm          = bdrv_default_perms,
     .bdrv_co_create      = vdi_co_create,
     .bdrv_co_create_opts = vdi_co_create_opts,
     .bdrv_has_zero_init  = vdi_has_zero_init,
diff --git a/block/vhdx.c b/block/vhdx.c
index 62c6bd69ff..fa9e544a5e 100644
--- a/block/vhdx.c
+++ b/block/vhdx.c
@@ -2245,7 +2245,7 @@ static BlockDriver bdrv_vhdx = {
     .bdrv_open              = vhdx_open,
     .bdrv_close             = vhdx_close,
     .bdrv_reopen_prepare    = vhdx_reopen_prepare,
-    .bdrv_child_perm        = bdrv_format_default_perms,
+    .bdrv_child_perm        = bdrv_default_perms,
     .bdrv_co_readv          = vhdx_co_readv,
     .bdrv_co_writev         = vhdx_co_writev,
     .bdrv_co_create         = vhdx_co_create,
diff --git a/block/vmdk.c b/block/vmdk.c
index fadc98a262..62da465126 100644
--- a/block/vmdk.c
+++ b/block/vmdk.c
@@ -3067,7 +3067,7 @@ static BlockDriver bdrv_vmdk = {
     .bdrv_open                    = vmdk_open,
     .bdrv_co_check                = vmdk_co_check,
     .bdrv_reopen_prepare          = vmdk_reopen_prepare,
-    .bdrv_child_perm              = bdrv_format_default_perms,
+    .bdrv_child_perm              = bdrv_default_perms,
     .bdrv_co_preadv               = vmdk_co_preadv,
     .bdrv_co_pwritev              = vmdk_co_pwritev,
     .bdrv_co_pwritev_compressed   = vmdk_co_pwritev_compressed,
diff --git a/block/vpc.c b/block/vpc.c
index 651a6737b6..c055591641 100644
--- a/block/vpc.c
+++ b/block/vpc.c
@@ -1240,7 +1240,7 @@ static BlockDriver bdrv_vpc = {
     .bdrv_open              = vpc_open,
     .bdrv_close             = vpc_close,
     .bdrv_reopen_prepare    = vpc_reopen_prepare,
-    .bdrv_child_perm        = bdrv_format_default_perms,
+    .bdrv_child_perm        = bdrv_default_perms,
     .bdrv_co_create         = vpc_co_create,
     .bdrv_co_create_opts    = vpc_co_create_opts,
 
diff --git a/tests/test-bdrv-drain.c b/tests/test-bdrv-drain.c
index 91567ca97d..0da5a3a6a1 100644
--- a/tests/test-bdrv-drain.c
+++ b/tests/test-bdrv-drain.c
@@ -93,15 +93,15 @@ static void bdrv_test_child_perm(BlockDriverState *bs, BdrvChild *c,
                                  uint64_t *nperm, uint64_t *nshared)
 {
     /*
-     * bdrv_format_default_perms() accepts only these two, so disguise
+     * bdrv_default_perms() accepts only these two, so disguise
      * detach_by_driver_cb_parent as one of them.
      */
     if (child_class != &child_file && child_class != &child_of_bds) {
         child_class = &child_of_bds;
     }
 
-    bdrv_format_default_perms(bs, c, child_class, role, reopen_queue,
-                              perm, shared, nperm, nshared);
+    bdrv_default_perms(bs, c, child_class, role, reopen_queue,
+                       perm, shared, nperm, nshared);
 }
 
 static int bdrv_test_change_backing_file(BlockDriverState *bs,
@@ -1137,7 +1137,7 @@ static BlockDriver bdrv_test_top_driver = {
     .bdrv_close             = bdrv_test_top_close,
     .bdrv_co_preadv         = bdrv_test_top_co_preadv,
 
-    .bdrv_child_perm        = bdrv_format_default_perms,
+    .bdrv_child_perm        = bdrv_default_perms,
 };
 
 typedef struct TestCoDeleteByDrainData {
@@ -1966,7 +1966,7 @@ static BlockDriver bdrv_replace_test = {
     .bdrv_co_drain_begin    = bdrv_replace_test_co_drain_begin,
     .bdrv_co_drain_end      = bdrv_replace_test_co_drain_end,
 
-    .bdrv_child_perm        = bdrv_format_default_perms,
+    .bdrv_child_perm        = bdrv_default_perms,
 };
 
 static void coroutine_fn test_replace_child_mid_drain_read_co(void *opaque)
diff --git a/tests/test-bdrv-graph-mod.c b/tests/test-bdrv-graph-mod.c
index 6ae91ff171..a2d0318b16 100644
--- a/tests/test-bdrv-graph-mod.c
+++ b/tests/test-bdrv-graph-mod.c
@@ -26,7 +26,7 @@
 
 static BlockDriver bdrv_pass_through = {
     .format_name = "pass-through",
-    .bdrv_child_perm = bdrv_filter_default_perms,
+    .bdrv_child_perm = bdrv_default_perms,
 };
 
 static void no_perm_default_perms(BlockDriverState *bs, BdrvChild *c,
diff --git a/tests/test-block-iothread.c b/tests/test-block-iothread.c
index 71e9bce3b1..a953794be2 100644
--- a/tests/test-block-iothread.c
+++ b/tests/test-block-iothread.c
@@ -482,8 +482,13 @@ static void test_propagate_basic(void)
     BlockDriverState *bs_a, *bs_b, *bs_verify;
     QDict *options;
 
-    /* Create bs_a and its BlockBackend */
-    blk = blk_new(qemu_get_aio_context(), BLK_PERM_ALL, BLK_PERM_ALL);
+    /*
+     * Create bs_a and its BlockBackend.  We cannot take the RESIZE
+     * permission because blkverify will not share it on the test
+     * image.
+     */
+    blk = blk_new(qemu_get_aio_context(), BLK_PERM_ALL & ~BLK_PERM_RESIZE,
+                  BLK_PERM_ALL);
     bs_a = bdrv_new_open_driver(&bdrv_test, "bs_a", BDRV_O_RDWR, &error_abort);
     blk_insert_bs(blk, bs_a, &error_abort);
 
@@ -566,7 +571,13 @@ static void test_propagate_diamond(void)
     qdict_put_str(options, "raw", "bs_c");
 
     bs_verify = bdrv_open(NULL, NULL, options, BDRV_O_RDWR, &error_abort);
-    blk = blk_new(qemu_get_aio_context(), BLK_PERM_ALL, BLK_PERM_ALL);
+    /*
+     * Do not take the RESIZE permission: This would require the same
+     * from bs_c and thus from bs_a; however, blkverify will not share
+     * it on bs_b, and thus it will not be available for bs_a.
+     */
+    blk = blk_new(qemu_get_aio_context(), BLK_PERM_ALL & ~BLK_PERM_RESIZE,
+                  BLK_PERM_ALL);
     blk_insert_bs(blk, bs_verify, &error_abort);
 
     /* Switch the AioContext */
-- 
2.26.2



^ permalink raw reply related	[flat|nested] 54+ messages in thread

* [PATCH v4 30/34] block: Make bdrv_filter_default_perms() static
  2020-05-13 11:05 [PATCH v4 00/34] block: Introduce real BdrvChildRole Max Reitz
                   ` (28 preceding siblings ...)
  2020-05-13 11:05 ` [PATCH v4 29/34] block: Use bdrv_default_perms() Max Reitz
@ 2020-05-13 11:05 ` Max Reitz
  2020-05-13 11:05 ` [PATCH v4 31/34] block: Drop bdrv_format_default_perms() Max Reitz
                   ` (5 subsequent siblings)
  35 siblings, 0 replies; 54+ messages in thread
From: Max Reitz @ 2020-05-13 11:05 UTC (permalink / raw)
  To: qemu-block; +Cc: Kevin Wolf, qemu-devel, Max Reitz

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
 include/block/block_int.h | 10 ----------
 block.c                   | 17 +++++++++++------
 2 files changed, 11 insertions(+), 16 deletions(-)

diff --git a/include/block/block_int.h b/include/block/block_int.h
index 0781d43af5..6fc5f0d333 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -1262,16 +1262,6 @@ int bdrv_child_try_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared,
  */
 int bdrv_child_refresh_perms(BlockDriverState *bs, BdrvChild *c, Error **errp);
 
-/* Default implementation for BlockDriver.bdrv_child_perm() that can be used by
- * block filters: Forward CONSISTENT_READ, WRITE, WRITE_UNCHANGED and RESIZE to
- * all children */
-void bdrv_filter_default_perms(BlockDriverState *bs, BdrvChild *c,
-                               const BdrvChildClass *child_class,
-                               BdrvChildRole child_role,
-                               BlockReopenQueue *reopen_queue,
-                               uint64_t perm, uint64_t shared,
-                               uint64_t *nperm, uint64_t *nshared);
-
 /* Default implementation for BlockDriver.bdrv_child_perm() that can be used by
  * (non-raw) image formats: Like above for bs->backing, but for bs->file it
  * requires WRITE | RESIZE for read-write images, always requires
diff --git a/block.c b/block.c
index fb94adcca4..54bc1c3b2d 100644
--- a/block.c
+++ b/block.c
@@ -2382,12 +2382,17 @@ int bdrv_child_refresh_perms(BlockDriverState *bs, BdrvChild *c, Error **errp)
     return bdrv_child_try_set_perm(c, perms, shared, errp);
 }
 
-void bdrv_filter_default_perms(BlockDriverState *bs, BdrvChild *c,
-                               const BdrvChildClass *child_class,
-                               BdrvChildRole role,
-                               BlockReopenQueue *reopen_queue,
-                               uint64_t perm, uint64_t shared,
-                               uint64_t *nperm, uint64_t *nshared)
+/*
+ * Default implementation for .bdrv_child_perm() for block filters:
+ * Forward CONSISTENT_READ, WRITE, WRITE_UNCHANGED, and RESIZE to the
+ * filtered child.
+ */
+static void bdrv_filter_default_perms(BlockDriverState *bs, BdrvChild *c,
+                                      const BdrvChildClass *child_class,
+                                      BdrvChildRole role,
+                                      BlockReopenQueue *reopen_queue,
+                                      uint64_t perm, uint64_t shared,
+                                      uint64_t *nperm, uint64_t *nshared)
 {
     *nperm = perm & DEFAULT_PERM_PASSTHROUGH;
     *nshared = (shared & DEFAULT_PERM_PASSTHROUGH) | DEFAULT_PERM_UNCHANGED;
-- 
2.26.2



^ permalink raw reply related	[flat|nested] 54+ messages in thread

* [PATCH v4 31/34] block: Drop bdrv_format_default_perms()
  2020-05-13 11:05 [PATCH v4 00/34] block: Introduce real BdrvChildRole Max Reitz
                   ` (29 preceding siblings ...)
  2020-05-13 11:05 ` [PATCH v4 30/34] block: Make bdrv_filter_default_perms() static Max Reitz
@ 2020-05-13 11:05 ` Max Reitz
  2020-05-13 11:05 ` [PATCH v4 32/34] block: Drop child_file Max Reitz
                   ` (4 subsequent siblings)
  35 siblings, 0 replies; 54+ messages in thread
From: Max Reitz @ 2020-05-13 11:05 UTC (permalink / raw)
  To: qemu-block; +Cc: Kevin Wolf, qemu-devel, Max Reitz

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
 include/block/block_int.h | 11 -----------
 block.c                   | 19 -------------------
 2 files changed, 30 deletions(-)

diff --git a/include/block/block_int.h b/include/block/block_int.h
index 6fc5f0d333..e791c40496 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -1262,17 +1262,6 @@ int bdrv_child_try_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared,
  */
 int bdrv_child_refresh_perms(BlockDriverState *bs, BdrvChild *c, Error **errp);
 
-/* Default implementation for BlockDriver.bdrv_child_perm() that can be used by
- * (non-raw) image formats: Like above for bs->backing, but for bs->file it
- * requires WRITE | RESIZE for read-write images, always requires
- * CONSISTENT_READ and doesn't share WRITE. */
-void bdrv_format_default_perms(BlockDriverState *bs, BdrvChild *c,
-                               const BdrvChildClass *child_class,
-                               BdrvChildRole child_role,
-                               BlockReopenQueue *reopen_queue,
-                               uint64_t perm, uint64_t shared,
-                               uint64_t *nperm, uint64_t *nshared);
-
 bool bdrv_recurse_can_replace(BlockDriverState *bs,
                               BlockDriverState *to_replace);
 
diff --git a/block.c b/block.c
index 54bc1c3b2d..e79fe6e07e 100644
--- a/block.c
+++ b/block.c
@@ -2517,25 +2517,6 @@ static void bdrv_default_perms_for_storage(BlockDriverState *bs, BdrvChild *c,
     *nshared = shared;
 }
 
-void bdrv_format_default_perms(BlockDriverState *bs, BdrvChild *c,
-                               const BdrvChildClass *child_class,
-                               BdrvChildRole role,
-                               BlockReopenQueue *reopen_queue,
-                               uint64_t perm, uint64_t shared,
-                               uint64_t *nperm, uint64_t *nshared)
-{
-    if (child_class == &child_of_bds) {
-        bdrv_default_perms(bs, c, child_class, role, reopen_queue,
-                           perm, shared, nperm, nshared);
-        return;
-    }
-
-    assert(child_class == &child_file);
-
-    bdrv_default_perms_for_storage(bs, c, child_class, role, reopen_queue,
-                                   perm, shared, nperm, nshared);
-}
-
 void bdrv_default_perms(BlockDriverState *bs, BdrvChild *c,
                         const BdrvChildClass *child_class, BdrvChildRole role,
                         BlockReopenQueue *reopen_queue,
-- 
2.26.2



^ permalink raw reply related	[flat|nested] 54+ messages in thread

* [PATCH v4 32/34] block: Drop child_file
  2020-05-13 11:05 [PATCH v4 00/34] block: Introduce real BdrvChildRole Max Reitz
                   ` (30 preceding siblings ...)
  2020-05-13 11:05 ` [PATCH v4 31/34] block: Drop bdrv_format_default_perms() Max Reitz
@ 2020-05-13 11:05 ` Max Reitz
  2020-05-13 21:11   ` Eric Blake
  2020-05-13 11:05 ` [PATCH v4 33/34] block: Pass BdrvChildRole in remaining cases Max Reitz
                   ` (3 subsequent siblings)
  35 siblings, 1 reply; 54+ messages in thread
From: Max Reitz @ 2020-05-13 11:05 UTC (permalink / raw)
  To: qemu-block; +Cc: Kevin Wolf, qemu-devel, Max Reitz

Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 include/block/block_int.h |  1 -
 block.c                   | 39 ++-------------------------------------
 tests/test-bdrv-drain.c   |  8 +++-----
 3 files changed, 5 insertions(+), 43 deletions(-)

diff --git a/include/block/block_int.h b/include/block/block_int.h
index e791c40496..7fbe3206b4 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -741,7 +741,6 @@ struct BdrvChildClass {
 };
 
 extern const BdrvChildClass child_of_bds;
-extern const BdrvChildClass child_file;
 
 struct BdrvChild {
     BlockDriverState *bs;
diff --git a/block.c b/block.c
index e79fe6e07e..6a24b23d51 100644
--- a/block.c
+++ b/block.c
@@ -80,13 +80,6 @@ static BlockDriverState *bdrv_open_inherit(const char *filename,
                                            BdrvChildRole child_role,
                                            Error **errp);
 
-/* TODO: Remove when no longer needed */
-static void bdrv_inherited_options(BdrvChildRole role, bool parent_is_format,
-                                   int *child_flags, QDict *child_options,
-                                   int parent_flags, QDict *parent_options);
-static void bdrv_child_cb_attach(BdrvChild *child);
-static void bdrv_child_cb_detach(BdrvChild *child);
-
 /* If non-zero, use only whitelisted block drivers */
 static int use_bdrv_whitelist;
 
@@ -1145,33 +1138,6 @@ static void bdrv_temp_snapshot_options(int *child_flags, QDict *child_options,
     *child_flags &= ~BDRV_O_NATIVE_AIO;
 }
 
-/*
- * Returns the options and flags that bs->file should get if a protocol driver
- * is expected, based on the given options and flags for the parent BDS
- */
-static void bdrv_protocol_options(BdrvChildRole role, bool parent_is_format,
-                                  int *child_flags, QDict *child_options,
-                                  int parent_flags, QDict *parent_options)
-{
-    bdrv_inherited_options(BDRV_CHILD_IMAGE, true,
-                           child_flags, child_options,
-                           parent_flags, parent_options);
-}
-
-const BdrvChildClass child_file = {
-    .parent_is_bds   = true,
-    .get_parent_desc = bdrv_child_get_parent_desc,
-    .inherit_options = bdrv_protocol_options,
-    .drained_begin   = bdrv_child_cb_drained_begin,
-    .drained_poll    = bdrv_child_cb_drained_poll,
-    .drained_end     = bdrv_child_cb_drained_end,
-    .attach          = bdrv_child_cb_attach,
-    .detach          = bdrv_child_cb_detach,
-    .inactivate      = bdrv_child_cb_inactivate,
-    .can_set_aio_ctx = bdrv_child_cb_can_set_aio_ctx,
-    .set_aio_ctx     = bdrv_child_cb_set_aio_ctx,
-};
-
 static void bdrv_backing_attach(BdrvChild *c)
 {
     BlockDriverState *parent = c->opaque;
@@ -2444,9 +2410,8 @@ static void bdrv_default_perms_for_storage(BlockDriverState *bs, BdrvChild *c,
 {
     int flags;
 
-    assert(child_class == &child_file ||
-           (child_class == &child_of_bds &&
-            (role & (BDRV_CHILD_METADATA | BDRV_CHILD_DATA))));
+    assert(child_class == &child_of_bds &&
+           (role & (BDRV_CHILD_METADATA | BDRV_CHILD_DATA)));
 
     flags = bdrv_reopen_get_flags(reopen_queue, bs);
 
diff --git a/tests/test-bdrv-drain.c b/tests/test-bdrv-drain.c
index 0da5a3a6a1..655fd0d085 100644
--- a/tests/test-bdrv-drain.c
+++ b/tests/test-bdrv-drain.c
@@ -93,12 +93,10 @@ static void bdrv_test_child_perm(BlockDriverState *bs, BdrvChild *c,
                                  uint64_t *nperm, uint64_t *nshared)
 {
     /*
-     * bdrv_default_perms() accepts only these two, so disguise
-     * detach_by_driver_cb_parent as one of them.
+     * bdrv_default_perms() accepts nothing else, so disguise
+     * detach_by_driver_cb_parent.
      */
-    if (child_class != &child_file && child_class != &child_of_bds) {
-        child_class = &child_of_bds;
-    }
+    child_class = &child_of_bds;
 
     bdrv_default_perms(bs, c, child_class, role, reopen_queue,
                        perm, shared, nperm, nshared);
-- 
2.26.2



^ permalink raw reply related	[flat|nested] 54+ messages in thread

* [PATCH v4 33/34] block: Pass BdrvChildRole in remaining cases
  2020-05-13 11:05 [PATCH v4 00/34] block: Introduce real BdrvChildRole Max Reitz
                   ` (31 preceding siblings ...)
  2020-05-13 11:05 ` [PATCH v4 32/34] block: Drop child_file Max Reitz
@ 2020-05-13 11:05 ` Max Reitz
  2020-05-13 21:12   ` Eric Blake
  2020-05-13 11:05 ` [PATCH v4 34/34] block: Drop @child_class from bdrv_child_perm() Max Reitz
                   ` (2 subsequent siblings)
  35 siblings, 1 reply; 54+ messages in thread
From: Max Reitz @ 2020-05-13 11:05 UTC (permalink / raw)
  To: qemu-block; +Cc: Kevin Wolf, qemu-devel, Max Reitz

These calls have no real use for the child role yet, but it will not
harm to give one.

Notably, the bdrv_root_attach_child() call in blockjob.c is left
unmodified because there is not much the generic BlockJob object wants
from its children.

Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 block/block-backend.c | 11 +++++++----
 block/vvfat.c         |  4 +++-
 2 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/block/block-backend.c b/block/block-backend.c
index f2e81af27d..6936b25c83 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -424,8 +424,9 @@ BlockBackend *blk_new_open(const char *filename, const char *reference,
         return NULL;
     }
 
-    blk->root = bdrv_root_attach_child(bs, "root", &child_root, 0, blk->ctx,
-                                       perm, BLK_PERM_ALL, blk, errp);
+    blk->root = bdrv_root_attach_child(bs, "root", &child_root,
+                                       BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY,
+                                       blk->ctx, perm, BLK_PERM_ALL, blk, errp);
     if (!blk->root) {
         blk_unref(blk);
         return NULL;
@@ -835,8 +836,10 @@ int blk_insert_bs(BlockBackend *blk, BlockDriverState *bs, Error **errp)
 {
     ThrottleGroupMember *tgm = &blk->public.throttle_group_member;
     bdrv_ref(bs);
-    blk->root = bdrv_root_attach_child(bs, "root", &child_root, 0, blk->ctx,
-                                       blk->perm, blk->shared_perm, blk, errp);
+    blk->root = bdrv_root_attach_child(bs, "root", &child_root,
+                                       BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY,
+                                       blk->ctx, blk->perm, blk->shared_perm,
+                                       blk, errp);
     if (blk->root == NULL) {
         return -EPERM;
     }
diff --git a/block/vvfat.c b/block/vvfat.c
index e8848a0497..089abe1e29 100644
--- a/block/vvfat.c
+++ b/block/vvfat.c
@@ -3184,7 +3184,9 @@ static int enable_write_target(BlockDriverState *bs, Error **errp)
     options = qdict_new();
     qdict_put_str(options, "write-target.driver", "qcow");
     s->qcow = bdrv_open_child(s->qcow_filename, options, "write-target", bs,
-                              &child_vvfat_qcow, 0, false, errp);
+                              &child_vvfat_qcow,
+                              BDRV_CHILD_DATA | BDRV_CHILD_METADATA,
+                              false, errp);
     qobject_unref(options);
     if (!s->qcow) {
         ret = -EINVAL;
-- 
2.26.2



^ permalink raw reply related	[flat|nested] 54+ messages in thread

* [PATCH v4 34/34] block: Drop @child_class from bdrv_child_perm()
  2020-05-13 11:05 [PATCH v4 00/34] block: Introduce real BdrvChildRole Max Reitz
                   ` (32 preceding siblings ...)
  2020-05-13 11:05 ` [PATCH v4 33/34] block: Pass BdrvChildRole in remaining cases Max Reitz
@ 2020-05-13 11:05 ` Max Reitz
  2020-05-13 21:15   ` Eric Blake
  2020-05-13 16:36 ` [PATCH v4 00/34] block: Introduce real BdrvChildRole Kevin Wolf
  2020-05-14 13:44 ` Kevin Wolf
  35 siblings, 1 reply; 54+ messages in thread
From: Max Reitz @ 2020-05-13 11:05 UTC (permalink / raw)
  To: qemu-block; +Cc: Kevin Wolf, qemu-devel, Max Reitz

Implementations should decide the necessary permissions based on @role.

Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 include/block/block_int.h   |  4 +---
 block.c                     | 39 +++++++++++++++----------------------
 block/backup-top.c          |  3 +--
 block/blkdebug.c            |  3 +--
 block/blklogwrites.c        |  3 +--
 block/commit.c              |  1 -
 block/copy-on-read.c        |  1 -
 block/mirror.c              |  1 -
 block/quorum.c              |  1 -
 block/replication.c         |  1 -
 block/vvfat.c               |  4 +---
 tests/test-bdrv-drain.c     | 19 +-----------------
 tests/test-bdrv-graph-mod.c |  1 -
 13 files changed, 22 insertions(+), 59 deletions(-)

diff --git a/include/block/block_int.h b/include/block/block_int.h
index 7fbe3206b4..5e4f4c348c 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -563,7 +563,6 @@ struct BlockDriver {
      * @reopen_queue.
      */
      void (*bdrv_child_perm)(BlockDriverState *bs, BdrvChild *c,
-                             const BdrvChildClass *child_class,
                              BdrvChildRole role,
                              BlockReopenQueue *reopen_queue,
                              uint64_t parent_perm, uint64_t parent_shared,
@@ -1270,8 +1269,7 @@ bool bdrv_recurse_can_replace(BlockDriverState *bs,
  * child_of_bds child class and set an appropriate BdrvChildRole.
  */
 void bdrv_default_perms(BlockDriverState *bs, BdrvChild *c,
-                        const BdrvChildClass *child_class, BdrvChildRole role,
-                        BlockReopenQueue *reopen_queue,
+                        BdrvChildRole role, BlockReopenQueue *reopen_queue,
                         uint64_t perm, uint64_t shared,
                         uint64_t *nperm, uint64_t *nshared);
 
diff --git a/block.c b/block.c
index 6a24b23d51..8416376c9b 100644
--- a/block.c
+++ b/block.c
@@ -1947,13 +1947,13 @@ bool bdrv_is_writable(BlockDriverState *bs)
 }
 
 static void bdrv_child_perm(BlockDriverState *bs, BlockDriverState *child_bs,
-                            BdrvChild *c, const BdrvChildClass *child_class,
-                            BdrvChildRole role, BlockReopenQueue *reopen_queue,
+                            BdrvChild *c, BdrvChildRole role,
+                            BlockReopenQueue *reopen_queue,
                             uint64_t parent_perm, uint64_t parent_shared,
                             uint64_t *nperm, uint64_t *nshared)
 {
     assert(bs->drv && bs->drv->bdrv_child_perm);
-    bs->drv->bdrv_child_perm(bs, c, child_class, role, reopen_queue,
+    bs->drv->bdrv_child_perm(bs, c, role, reopen_queue,
                              parent_perm, parent_shared,
                              nperm, nshared);
     /* TODO Take force_share from reopen_queue */
@@ -2047,7 +2047,7 @@ static int bdrv_check_perm(BlockDriverState *bs, BlockReopenQueue *q,
         uint64_t cur_perm, cur_shared;
         bool child_tighten_restr;
 
-        bdrv_child_perm(bs, c->bs, c, c->klass, c->role, q,
+        bdrv_child_perm(bs, c->bs, c, c->role, q,
                         cumulative_perms, cumulative_shared_perms,
                         &cur_perm, &cur_shared);
         ret = bdrv_child_check_perm(c, q, cur_perm, cur_shared, ignore_children,
@@ -2114,7 +2114,7 @@ static void bdrv_set_perm(BlockDriverState *bs, uint64_t cumulative_perms,
     /* Update all children */
     QLIST_FOREACH(c, &bs->children, next) {
         uint64_t cur_perm, cur_shared;
-        bdrv_child_perm(bs, c->bs, c, c->klass, c->role, NULL,
+        bdrv_child_perm(bs, c->bs, c, c->role, NULL,
                         cumulative_perms, cumulative_shared_perms,
                         &cur_perm, &cur_shared);
         bdrv_child_set_perm(c, cur_perm, cur_shared);
@@ -2342,7 +2342,7 @@ int bdrv_child_refresh_perms(BlockDriverState *bs, BdrvChild *c, Error **errp)
     uint64_t perms, shared;
 
     bdrv_get_cumulative_perm(bs, &parent_perms, &parent_shared);
-    bdrv_child_perm(bs, c->bs, c, c->klass, c->role, NULL,
+    bdrv_child_perm(bs, c->bs, c, c->role, NULL,
                     parent_perms, parent_shared, &perms, &shared);
 
     return bdrv_child_try_set_perm(c, perms, shared, errp);
@@ -2354,7 +2354,6 @@ int bdrv_child_refresh_perms(BlockDriverState *bs, BdrvChild *c, Error **errp)
  * filtered child.
  */
 static void bdrv_filter_default_perms(BlockDriverState *bs, BdrvChild *c,
-                                      const BdrvChildClass *child_class,
                                       BdrvChildRole role,
                                       BlockReopenQueue *reopen_queue,
                                       uint64_t perm, uint64_t shared,
@@ -2365,13 +2364,12 @@ static void bdrv_filter_default_perms(BlockDriverState *bs, BdrvChild *c,
 }
 
 static void bdrv_default_perms_for_cow(BlockDriverState *bs, BdrvChild *c,
-                                       const BdrvChildClass *child_class,
                                        BdrvChildRole role,
                                        BlockReopenQueue *reopen_queue,
                                        uint64_t perm, uint64_t shared,
                                        uint64_t *nperm, uint64_t *nshared)
 {
-    assert(child_class == &child_of_bds && (role & BDRV_CHILD_COW));
+    assert(role & BDRV_CHILD_COW);
 
     /*
      * We want consistent read from backing files if the parent needs it.
@@ -2402,7 +2400,6 @@ static void bdrv_default_perms_for_cow(BlockDriverState *bs, BdrvChild *c,
 }
 
 static void bdrv_default_perms_for_storage(BlockDriverState *bs, BdrvChild *c,
-                                           const BdrvChildClass *child_class,
                                            BdrvChildRole role,
                                            BlockReopenQueue *reopen_queue,
                                            uint64_t perm, uint64_t shared,
@@ -2410,8 +2407,7 @@ static void bdrv_default_perms_for_storage(BlockDriverState *bs, BdrvChild *c,
 {
     int flags;
 
-    assert(child_class == &child_of_bds &&
-           (role & (BDRV_CHILD_METADATA | BDRV_CHILD_DATA)));
+    assert(role & (BDRV_CHILD_METADATA | BDRV_CHILD_DATA));
 
     flags = bdrv_reopen_get_flags(reopen_queue, bs);
 
@@ -2419,7 +2415,7 @@ static void bdrv_default_perms_for_storage(BlockDriverState *bs, BdrvChild *c,
      * Apart from the modifications below, the same permissions are
      * forwarded and left alone as for filters
      */
-    bdrv_filter_default_perms(bs, c, child_class, role, reopen_queue,
+    bdrv_filter_default_perms(bs, c, role, reopen_queue,
                               perm, shared, &perm, &shared);
 
     if (role & BDRV_CHILD_METADATA) {
@@ -2483,24 +2479,21 @@ static void bdrv_default_perms_for_storage(BlockDriverState *bs, BdrvChild *c,
 }
 
 void bdrv_default_perms(BlockDriverState *bs, BdrvChild *c,
-                        const BdrvChildClass *child_class, BdrvChildRole role,
-                        BlockReopenQueue *reopen_queue,
+                        BdrvChildRole role, BlockReopenQueue *reopen_queue,
                         uint64_t perm, uint64_t shared,
                         uint64_t *nperm, uint64_t *nshared)
 {
-    assert(child_class == &child_of_bds);
-
     if (role & BDRV_CHILD_FILTERED) {
         assert(!(role & (BDRV_CHILD_DATA | BDRV_CHILD_METADATA |
                          BDRV_CHILD_COW)));
-        bdrv_filter_default_perms(bs, c, child_class, role, reopen_queue,
+        bdrv_filter_default_perms(bs, c, role, reopen_queue,
                                   perm, shared, nperm, nshared);
     } else if (role & BDRV_CHILD_COW) {
         assert(!(role & (BDRV_CHILD_DATA | BDRV_CHILD_METADATA)));
-        bdrv_default_perms_for_cow(bs, c, child_class, role, reopen_queue,
+        bdrv_default_perms_for_cow(bs, c, role, reopen_queue,
                                    perm, shared, nperm, nshared);
     } else if (role & (BDRV_CHILD_METADATA | BDRV_CHILD_DATA)) {
-        bdrv_default_perms_for_storage(bs, c, child_class, role, reopen_queue,
+        bdrv_default_perms_for_storage(bs, c, role, reopen_queue,
                                        perm, shared, nperm, nshared);
     } else {
         g_assert_not_reached();
@@ -2744,7 +2737,7 @@ BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs,
     bdrv_get_cumulative_perm(parent_bs, &perm, &shared_perm);
 
     assert(parent_bs->drv);
-    bdrv_child_perm(parent_bs, child_bs, NULL, child_class, child_role, NULL,
+    bdrv_child_perm(parent_bs, child_bs, NULL, child_role, NULL,
                     perm, shared_perm, &perm, &shared_perm);
 
     child = bdrv_root_attach_child(child_bs, child_name, child_class,
@@ -3807,7 +3800,7 @@ int bdrv_reopen_multiple(BlockReopenQueue *bs_queue, Error **errp)
         if (state->replace_backing_bs && state->new_backing_bs) {
             uint64_t nperm, nshared;
             bdrv_child_perm(state->bs, state->new_backing_bs,
-                            NULL, &child_of_bds, bdrv_backing_role(state->bs),
+                            NULL, bdrv_backing_role(state->bs),
                             bs_queue, state->perm, state->shared_perm,
                             &nperm, &nshared);
             ret = bdrv_check_update_perm(state->new_backing_bs, NULL,
@@ -3930,7 +3923,7 @@ static void bdrv_reopen_perm(BlockReopenQueue *q, BlockDriverState *bs,
         } else {
             uint64_t nperm, nshared;
 
-            bdrv_child_perm(parent->state.bs, bs, c, c->klass, c->role, q,
+            bdrv_child_perm(parent->state.bs, bs, c, c->role, q,
                             parent->state.perm, parent->state.shared_perm,
                             &nperm, &nshared);
 
diff --git a/block/backup-top.c b/block/backup-top.c
index f0efec18b5..af2f20f346 100644
--- a/block/backup-top.c
+++ b/block/backup-top.c
@@ -122,7 +122,6 @@ static void backup_top_refresh_filename(BlockDriverState *bs)
 }
 
 static void backup_top_child_perm(BlockDriverState *bs, BdrvChild *c,
-                                  const BdrvChildClass *child_class,
                                   BdrvChildRole role,
                                   BlockReopenQueue *reopen_queue,
                                   uint64_t perm, uint64_t shared,
@@ -156,7 +155,7 @@ static void backup_top_child_perm(BlockDriverState *bs, BdrvChild *c,
         *nperm = BLK_PERM_WRITE;
     } else {
         /* Source child */
-        bdrv_default_perms(bs, c, child_class, role, reopen_queue,
+        bdrv_default_perms(bs, c, role, reopen_queue,
                            perm, shared, nperm, nshared);
 
         if (perm & BLK_PERM_WRITE) {
diff --git a/block/blkdebug.c b/block/blkdebug.c
index a925d8295e..7194bc7f06 100644
--- a/block/blkdebug.c
+++ b/block/blkdebug.c
@@ -995,7 +995,6 @@ static int blkdebug_reopen_prepare(BDRVReopenState *reopen_state,
 }
 
 static void blkdebug_child_perm(BlockDriverState *bs, BdrvChild *c,
-                                const BdrvChildClass *child_class,
                                 BdrvChildRole role,
                                 BlockReopenQueue *reopen_queue,
                                 uint64_t perm, uint64_t shared,
@@ -1003,7 +1002,7 @@ static void blkdebug_child_perm(BlockDriverState *bs, BdrvChild *c,
 {
     BDRVBlkdebugState *s = bs->opaque;
 
-    bdrv_default_perms(bs, c, child_class, role, reopen_queue,
+    bdrv_default_perms(bs, c, role, reopen_queue,
                        perm, shared, nperm, nshared);
 
     *nperm |= s->take_child_perms;
diff --git a/block/blklogwrites.c b/block/blklogwrites.c
index 8684fb1c74..6753bd9a3e 100644
--- a/block/blklogwrites.c
+++ b/block/blklogwrites.c
@@ -283,7 +283,6 @@ static int64_t blk_log_writes_getlength(BlockDriverState *bs)
 }
 
 static void blk_log_writes_child_perm(BlockDriverState *bs, BdrvChild *c,
-                                      const BdrvChildClass *child_class,
                                       BdrvChildRole role,
                                       BlockReopenQueue *ro_q,
                                       uint64_t perm, uint64_t shrd,
@@ -295,7 +294,7 @@ static void blk_log_writes_child_perm(BlockDriverState *bs, BdrvChild *c,
         return;
     }
 
-    bdrv_default_perms(bs, c, child_class, role, ro_q, perm, shrd,
+    bdrv_default_perms(bs, c, role, ro_q, perm, shrd,
                        nperm, nshrd);
 }
 
diff --git a/block/commit.c b/block/commit.c
index 6af1c808bc..7732d02dfe 100644
--- a/block/commit.c
+++ b/block/commit.c
@@ -223,7 +223,6 @@ static void bdrv_commit_top_refresh_filename(BlockDriverState *bs)
 }
 
 static void bdrv_commit_top_child_perm(BlockDriverState *bs, BdrvChild *c,
-                                       const BdrvChildClass *child_class,
                                        BdrvChildRole role,
                                        BlockReopenQueue *reopen_queue,
                                        uint64_t perm, uint64_t shared,
diff --git a/block/copy-on-read.c b/block/copy-on-read.c
index c857ea0da7..a6e3c74a68 100644
--- a/block/copy-on-read.c
+++ b/block/copy-on-read.c
@@ -52,7 +52,6 @@ static int cor_open(BlockDriverState *bs, QDict *options, int flags,
 #define PERM_UNCHANGED (BLK_PERM_ALL & ~PERM_PASSTHROUGH)
 
 static void cor_child_perm(BlockDriverState *bs, BdrvChild *c,
-                           const BdrvChildClass *child_class,
                            BdrvChildRole role,
                            BlockReopenQueue *reopen_queue,
                            uint64_t perm, uint64_t shared,
diff --git a/block/mirror.c b/block/mirror.c
index cb4bdad32a..e8e8844afc 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -1492,7 +1492,6 @@ static void bdrv_mirror_top_refresh_filename(BlockDriverState *bs)
 }
 
 static void bdrv_mirror_top_child_perm(BlockDriverState *bs, BdrvChild *c,
-                                       const BdrvChildClass *child_class,
                                        BdrvChildRole role,
                                        BlockReopenQueue *reopen_queue,
                                        uint64_t perm, uint64_t shared,
diff --git a/block/quorum.c b/block/quorum.c
index 616ac3a927..7cf7ab1546 100644
--- a/block/quorum.c
+++ b/block/quorum.c
@@ -1153,7 +1153,6 @@ static char *quorum_dirname(BlockDriverState *bs, Error **errp)
 }
 
 static void quorum_child_perm(BlockDriverState *bs, BdrvChild *c,
-                              const BdrvChildClass *child_class,
                               BdrvChildRole role,
                               BlockReopenQueue *reopen_queue,
                               uint64_t perm, uint64_t shared,
diff --git a/block/replication.c b/block/replication.c
index ca78eb6785..c666176629 100644
--- a/block/replication.c
+++ b/block/replication.c
@@ -164,7 +164,6 @@ static void replication_close(BlockDriverState *bs)
 }
 
 static void replication_child_perm(BlockDriverState *bs, BdrvChild *c,
-                                   const BdrvChildClass *child_class,
                                    BdrvChildRole role,
                                    BlockReopenQueue *reopen_queue,
                                    uint64_t perm, uint64_t shared,
diff --git a/block/vvfat.c b/block/vvfat.c
index 089abe1e29..c65a98e3ee 100644
--- a/block/vvfat.c
+++ b/block/vvfat.c
@@ -3213,7 +3213,6 @@ err:
 }
 
 static void vvfat_child_perm(BlockDriverState *bs, BdrvChild *c,
-                             const BdrvChildClass *child_class,
                              BdrvChildRole role,
                              BlockReopenQueue *reopen_queue,
                              uint64_t perm, uint64_t shared,
@@ -3221,8 +3220,7 @@ static void vvfat_child_perm(BlockDriverState *bs, BdrvChild *c,
 {
     BDRVVVFATState *s = bs->opaque;
 
-    assert(c == s->qcow ||
-           (child_class == &child_of_bds && (role & BDRV_CHILD_COW)));
+    assert(c == s->qcow || (role & BDRV_CHILD_COW));
 
     if (c == s->qcow) {
         /* This is a private node, nobody should try to attach to it */
diff --git a/tests/test-bdrv-drain.c b/tests/test-bdrv-drain.c
index 655fd0d085..1107271840 100644
--- a/tests/test-bdrv-drain.c
+++ b/tests/test-bdrv-drain.c
@@ -85,23 +85,6 @@ static int coroutine_fn bdrv_test_co_preadv(BlockDriverState *bs,
     return 0;
 }
 
-static void bdrv_test_child_perm(BlockDriverState *bs, BdrvChild *c,
-                                 const BdrvChildClass *child_class,
-                                 BdrvChildRole role,
-                                 BlockReopenQueue *reopen_queue,
-                                 uint64_t perm, uint64_t shared,
-                                 uint64_t *nperm, uint64_t *nshared)
-{
-    /*
-     * bdrv_default_perms() accepts nothing else, so disguise
-     * detach_by_driver_cb_parent.
-     */
-    child_class = &child_of_bds;
-
-    bdrv_default_perms(bs, c, child_class, role, reopen_queue,
-                       perm, shared, nperm, nshared);
-}
-
 static int bdrv_test_change_backing_file(BlockDriverState *bs,
                                          const char *backing_file,
                                          const char *backing_fmt)
@@ -119,7 +102,7 @@ static BlockDriver bdrv_test = {
     .bdrv_co_drain_begin    = bdrv_test_co_drain_begin,
     .bdrv_co_drain_end      = bdrv_test_co_drain_end,
 
-    .bdrv_child_perm        = bdrv_test_child_perm,
+    .bdrv_child_perm        = bdrv_default_perms,
 
     .bdrv_change_backing_file = bdrv_test_change_backing_file,
 };
diff --git a/tests/test-bdrv-graph-mod.c b/tests/test-bdrv-graph-mod.c
index a2d0318b16..f93f3168b0 100644
--- a/tests/test-bdrv-graph-mod.c
+++ b/tests/test-bdrv-graph-mod.c
@@ -30,7 +30,6 @@ static BlockDriver bdrv_pass_through = {
 };
 
 static void no_perm_default_perms(BlockDriverState *bs, BdrvChild *c,
-                                         const BdrvChildClass *child_class,
                                          BdrvChildRole role,
                                          BlockReopenQueue *reopen_queue,
                                          uint64_t perm, uint64_t shared,
-- 
2.26.2



^ permalink raw reply related	[flat|nested] 54+ messages in thread

* Re: [PATCH v4 00/34] block: Introduce real BdrvChildRole
  2020-05-13 11:05 [PATCH v4 00/34] block: Introduce real BdrvChildRole Max Reitz
                   ` (33 preceding siblings ...)
  2020-05-13 11:05 ` [PATCH v4 34/34] block: Drop @child_class from bdrv_child_perm() Max Reitz
@ 2020-05-13 16:36 ` Kevin Wolf
  2020-05-14 13:44 ` Kevin Wolf
  35 siblings, 0 replies; 54+ messages in thread
From: Kevin Wolf @ 2020-05-13 16:36 UTC (permalink / raw)
  To: Max Reitz; +Cc: qemu-devel, qemu-block

Am 13.05.2020 um 13:05 hat Max Reitz geschrieben:
> Based-on: <20200429141126.85159-1-mreitz@redhat.com>
> (“block: Do not call BlockDriver.bdrv_make_empty() directly”)

I was just ready to apply the series, but alas, then I saw this
notice...

So for now, you'll have to make do with:

Reviewed-by: Kevin Wolf <kwolf@redhat.com>



^ permalink raw reply	[flat|nested] 54+ messages in thread

* Re: [PATCH v4 04/34] block: Add BdrvChildRole and BdrvChildRoleBits
  2020-05-13 11:05 ` [PATCH v4 04/34] block: Add BdrvChildRole and BdrvChildRoleBits Max Reitz
@ 2020-05-13 17:36   ` Eric Blake
  0 siblings, 0 replies; 54+ messages in thread
From: Eric Blake @ 2020-05-13 17:36 UTC (permalink / raw)
  To: Max Reitz, qemu-block; +Cc: Kevin Wolf, qemu-devel

On 5/13/20 6:05 AM, Max Reitz wrote:
> This mask will supplement BdrvChildClass when it comes to what role (or
> combination of roles) a child takes for its parent.  It consists of
> BdrvChildRoleBits values (which is an enum).
> 
> Because empty enums are not allowed, let us just start with it filled.
> 
> Signed-off-by: Max Reitz <mreitz@redhat.com>
> ---
>   include/block/block.h | 56 +++++++++++++++++++++++++++++++++++++++++++
>   1 file changed, 56 insertions(+)
> 
> diff --git a/include/block/block.h b/include/block/block.h
> index bc42e507bb..86cffa9ffd 100644
> --- a/include/block/block.h
> +++ b/include/block/block.h
> @@ -268,6 +268,62 @@ enum {
>       DEFAULT_PERM_UNCHANGED      = BLK_PERM_ALL & ~DEFAULT_PERM_PASSTHROUGH,
>   };
>   
> +/*
> + * Flags parent nodes give for the child nodes to specify what kind of
> + * role(s) they take.

Reads a bit awkwardly. Maybe:

Flags that parent nodes assign to child nodes to specify what kind of 
role(s) they take.

Touching up grammar doesn't affect code correctness, so:
Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org



^ permalink raw reply	[flat|nested] 54+ messages in thread

* Re: [PATCH v4 10/34] block: Add generic bdrv_inherited_options()
  2020-05-13 11:05 ` [PATCH v4 10/34] block: Add generic bdrv_inherited_options() Max Reitz
@ 2020-05-13 20:13   ` Eric Blake
  0 siblings, 0 replies; 54+ messages in thread
From: Eric Blake @ 2020-05-13 20:13 UTC (permalink / raw)
  To: Max Reitz, qemu-block; +Cc: Kevin Wolf, qemu-devel

On 5/13/20 6:05 AM, Max Reitz wrote:
> After the series this patch belongs to, we want to have a common
> BdrvChildClass that encompasses all of child_file, child_format, and
> child_backing.  Such a single class needs a single .inherit_options()
> implementation, and this patch introduces it.
> 
> The next patch will show how the existing implementations can fall back
> to it just by passing appropriate BdrvChildRole and parent_is_format
> values.
> 
> Signed-off-by: Max Reitz <mreitz@redhat.com>
> ---
>   block.c | 81 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>   1 file changed, 81 insertions(+)
> 

Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org



^ permalink raw reply	[flat|nested] 54+ messages in thread

* Re: [PATCH v4 11/34] block: Use bdrv_inherited_options()
  2020-05-13 11:05 ` [PATCH v4 11/34] block: Use bdrv_inherited_options() Max Reitz
@ 2020-05-13 20:18   ` Eric Blake
  0 siblings, 0 replies; 54+ messages in thread
From: Eric Blake @ 2020-05-13 20:18 UTC (permalink / raw)
  To: Max Reitz, qemu-block; +Cc: Kevin Wolf, qemu-devel

On 5/13/20 6:05 AM, Max Reitz wrote:
> Let child_file's, child_format's, and child_backing's .inherit_options()
> implementations fall back to bdrv_inherited_options() to show that it
> would really work for all of these cases, if only the parents passed the
> appropriate BdrvChildRole and parent_is_format values.
> 
> (Also, make bdrv_open_inherit(), the only place to explicitly call
> bdrv_backing_options(), call bdrv_inherited_options() instead.)
> 
> This patch should incur only two visible changes, both for child_format
> children, both of which are effectively bug fixes:
> 
> First, they no longer have discard=unmap set by default.  This reason it
> was set is because bdrv_inherited_fmt_options() fell through to
> bdrv_protocol_options(), and that set it because "format drivers take
> care to send flushes and respect unmap policy".  None of the drivers
> that use child_format for their children (quorum and blkverify) are
> format drivers, though, so this reasoning does not apply here.
> 
> Second, they no longer have BDRV_O_NO_IO force-cleared.  child_format
> was used solely for children that do not store any metadata and as such
> will not be accessed by their parents as long as those parents do not
> receive I/O themselves.  Thus, such children should inherit
> BDRV_O_NO_IO.
> 
> Signed-off-by: Max Reitz <mreitz@redhat.com>
> ---
>   block.c | 71 +++++++++++++++------------------------------------------
>   1 file changed, 19 insertions(+), 52 deletions(-)
> 

Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org



^ permalink raw reply	[flat|nested] 54+ messages in thread

* Re: [PATCH v4 12/34] block: Unify bdrv_child_cb_attach()
  2020-05-13 11:05 ` [PATCH v4 12/34] block: Unify bdrv_child_cb_attach() Max Reitz
@ 2020-05-13 20:26   ` Eric Blake
  0 siblings, 0 replies; 54+ messages in thread
From: Eric Blake @ 2020-05-13 20:26 UTC (permalink / raw)
  To: Max Reitz, qemu-block; +Cc: Kevin Wolf, qemu-devel

On 5/13/20 6:05 AM, Max Reitz wrote:
> Make bdrv_child_cb_attach() call bdrv_backing_attach() for children with
> a COW role (and drop the reverse call from bdrv_backing_attach()), so it
> can be used for any child (with a proper role set).
> 
> Because so far no child has a proper role set, we need a temporary new
> callback for child_backing.attach that ensures bdrv_backing_attach() is
> called for all COW children that do not have their role set yet.
> 
> (Also, move bdrv_child_cb_attach() down to group it with
> bdrv_inherited_options().)
> 
> Signed-off-by: Max Reitz <mreitz@redhat.com>
> ---
>   block.c | 27 ++++++++++++++++++++-------
>   1 file changed, 20 insertions(+), 7 deletions(-)
> 

Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org



^ permalink raw reply	[flat|nested] 54+ messages in thread

* Re: [PATCH v4 13/34] block: Unify bdrv_child_cb_detach()
  2020-05-13 11:05 ` [PATCH v4 13/34] block: Unify bdrv_child_cb_detach() Max Reitz
@ 2020-05-13 20:27   ` Eric Blake
  0 siblings, 0 replies; 54+ messages in thread
From: Eric Blake @ 2020-05-13 20:27 UTC (permalink / raw)
  To: Max Reitz, qemu-block; +Cc: Kevin Wolf, qemu-devel

On 5/13/20 6:05 AM, Max Reitz wrote:
> Make bdrv_child_cb_detach() call bdrv_backing_detach() for children with
> a COW role (and drop the reverse call from bdrv_backing_detach()), so it
> can be used for any child (with a proper role set).
> 
> Because so far no child has a proper role set, we need a temporary new
> callback for child_backing.detach that ensures bdrv_backing_detach() is
> called for all COW children that do not have their role set yet.
> 
> (Also, move bdrv_child_cb_detach() down to group it with
> bdrv_inherited_options() and bdrv_child_cb_attach().)
> 
> Signed-off-by: Max Reitz <mreitz@redhat.com>
> ---
>   block.c | 27 ++++++++++++++++++++-------
>   1 file changed, 20 insertions(+), 7 deletions(-)
> 

Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org



^ permalink raw reply	[flat|nested] 54+ messages in thread

* Re: [PATCH v4 14/34] block: Add child_of_bds
  2020-05-13 11:05 ` [PATCH v4 14/34] block: Add child_of_bds Max Reitz
@ 2020-05-13 20:29   ` Eric Blake
  0 siblings, 0 replies; 54+ messages in thread
From: Eric Blake @ 2020-05-13 20:29 UTC (permalink / raw)
  To: Max Reitz, qemu-block; +Cc: Kevin Wolf, qemu-devel

On 5/13/20 6:05 AM, Max Reitz wrote:
> Any current user of child_file, child_format, and child_backing can and
> should use this generic BdrvChildClass instead, as it can handle all of
> these cases.  However, to be able to do so, the users must pass the
> appropriate BdrvChildRole when the child is created/attached.  (The
> following commits will take care of that.)
> 
> Signed-off-by: Max Reitz <mreitz@redhat.com>
> ---
>   include/block/block_int.h |  1 +
>   block.c                   | 24 ++++++++++++++++++++++++
>   2 files changed, 25 insertions(+)
> 

Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org



^ permalink raw reply	[flat|nested] 54+ messages in thread

* Re: [PATCH v4 15/34] block: Distinguish paths in *_format_default_perms
  2020-05-13 11:05 ` [PATCH v4 15/34] block: Distinguish paths in *_format_default_perms Max Reitz
@ 2020-05-13 20:30   ` Eric Blake
  0 siblings, 0 replies; 54+ messages in thread
From: Eric Blake @ 2020-05-13 20:30 UTC (permalink / raw)
  To: Max Reitz, qemu-block; +Cc: Kevin Wolf, qemu-devel

On 5/13/20 6:05 AM, Max Reitz wrote:
> bdrv_format_default_perms() has one code path for backing files, and one
> for storage files.  We want to pull them out into own functions, so

Grammar suggestion: s/into own/into their own/

> make sure they are completely distinct before so the next patches will
> be a bit cleaner.
> 
> Signed-off-by: Max Reitz <mreitz@redhat.com>
> Reviewed-by: Eric Blake <eblake@redhat.com>

R-b still stands.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org



^ permalink raw reply	[flat|nested] 54+ messages in thread

* Re: [PATCH v4 16/34] block: Pull out bdrv_default_perms_for_cow()
  2020-05-13 11:05 ` [PATCH v4 16/34] block: Pull out bdrv_default_perms_for_cow() Max Reitz
@ 2020-05-13 20:33   ` Eric Blake
  0 siblings, 0 replies; 54+ messages in thread
From: Eric Blake @ 2020-05-13 20:33 UTC (permalink / raw)
  To: Max Reitz, qemu-block; +Cc: Kevin Wolf, qemu-devel

On 5/13/20 6:05 AM, Max Reitz wrote:
> Right now, bdrv_format_default_perms() is used by format parents
> (generally). We want to switch to a model where most parents use a
> single BdrvChildClass, which then decides the permissions based on the
> child role. To do so, we have to split bdrv_format_default_perms() into
> separate functions for each such role.
> 
> Signed-off-by: Max Reitz <mreitz@redhat.com>
> ---
>   block.c | 62 +++++++++++++++++++++++++++++++++++++--------------------
>   1 file changed, 40 insertions(+), 22 deletions(-)
> 

Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org



^ permalink raw reply	[flat|nested] 54+ messages in thread

* Re: [PATCH v4 18/34] block: Relax *perms_for_storage for data children
  2020-05-13 11:05 ` [PATCH v4 18/34] block: Relax *perms_for_storage for data children Max Reitz
@ 2020-05-13 20:38   ` Eric Blake
  0 siblings, 0 replies; 54+ messages in thread
From: Eric Blake @ 2020-05-13 20:38 UTC (permalink / raw)
  To: Max Reitz, qemu-block; +Cc: Kevin Wolf, qemu-devel

On 5/13/20 6:05 AM, Max Reitz wrote:
> We can be less restrictive about pure data children than those with
> metadata on them, so let bdrv_default_perms_for_storage() handle
> metadata children differently from pure data children.
> 
> As explained in the code, the restrictions on metadata children are
> strictly stricter than those for pure data children, so in theory we
> just have to distinguish between pure-data and all other storage
> children (pure metadata or data+metadata).  In practice, that is not
> obvious, though, so we have two independent code paths for metadata and
> for data children, and data+metadata children will go through both
> (without the path for data children doing anything meaningful).
> 
> Signed-off-by: Max Reitz <mreitz@redhat.com>
> ---
>   block.c | 58 +++++++++++++++++++++++++++++++++++++++++++++++----------
>   1 file changed, 48 insertions(+), 10 deletions(-)
> 

Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org



^ permalink raw reply	[flat|nested] 54+ messages in thread

* Re: [PATCH v4 19/34] block: Add bdrv_default_perms()
  2020-05-13 11:05 ` [PATCH v4 19/34] block: Add bdrv_default_perms() Max Reitz
@ 2020-05-13 20:43   ` Eric Blake
  0 siblings, 0 replies; 54+ messages in thread
From: Eric Blake @ 2020-05-13 20:43 UTC (permalink / raw)
  To: Max Reitz, qemu-block; +Cc: Kevin Wolf, qemu-devel

On 5/13/20 6:05 AM, Max Reitz wrote:
> This callback can be used by BDSs that use child_of_bds with the
> appropriate BdrvChildRole for their children.
> 
> Also, make bdrv_format_default_perms() use it for child_of_bds children
> (just a temporary solution until we can drop bdrv_format_default_perms()
> altogether).
> 
> Signed-off-by: Max Reitz <mreitz@redhat.com>
> ---
>   include/block/block_int.h | 11 +++++++++++
>   block.c                   | 32 ++++++++++++++++++++++++++++++++
>   2 files changed, 43 insertions(+)
> 
Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org



^ permalink raw reply	[flat|nested] 54+ messages in thread

* Re: [PATCH v4 23/34] block: Make backing files child_of_bds children
  2020-05-13 11:05 ` [PATCH v4 23/34] block: Make backing files child_of_bds children Max Reitz
@ 2020-05-13 20:46   ` Eric Blake
  0 siblings, 0 replies; 54+ messages in thread
From: Eric Blake @ 2020-05-13 20:46 UTC (permalink / raw)
  To: Max Reitz, qemu-block; +Cc: Kevin Wolf, qemu-devel

On 5/13/20 6:05 AM, Max Reitz wrote:
> Make all parents of backing files pass the appropriate BdrvChildRole.
> By doing so, we can switch their BdrvChildClass over to the generic
> child_of_bds, which will do the right thing when given a correct
> BdrvChildRole.
> 
> Signed-off-by: Max Reitz <mreitz@redhat.com>
> ---
>   block.c                 | 26 ++++++++++++++++++++------
>   block/backup-top.c      |  2 +-
>   block/vvfat.c           |  3 ++-
>   tests/test-bdrv-drain.c | 13 +++++++------
>   4 files changed, 30 insertions(+), 14 deletions(-)
> 
Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org



^ permalink raw reply	[flat|nested] 54+ messages in thread

* Re: [PATCH v4 24/34] block: Drop child_backing
  2020-05-13 11:05 ` [PATCH v4 24/34] block: Drop child_backing Max Reitz
@ 2020-05-13 20:47   ` Eric Blake
  0 siblings, 0 replies; 54+ messages in thread
From: Eric Blake @ 2020-05-13 20:47 UTC (permalink / raw)
  To: Max Reitz, qemu-block; +Cc: Kevin Wolf, qemu-devel

On 5/13/20 6:05 AM, Max Reitz wrote:
> Signed-off-by: Max Reitz <mreitz@redhat.com>
> ---
>   include/block/block_int.h |  1 -
>   block.c                   | 60 ++-------------------------------------
>   2 files changed, 3 insertions(+), 58 deletions(-)
> 

Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org



^ permalink raw reply	[flat|nested] 54+ messages in thread

* Re: [PATCH v4 26/34] block: Make filter drivers use child_of_bds
  2020-05-13 11:05 ` [PATCH v4 26/34] block: Make filter " Max Reitz
@ 2020-05-13 21:02   ` Eric Blake
  0 siblings, 0 replies; 54+ messages in thread
From: Eric Blake @ 2020-05-13 21:02 UTC (permalink / raw)
  To: Max Reitz, qemu-block; +Cc: Kevin Wolf, qemu-devel

On 5/13/20 6:05 AM, Max Reitz wrote:
> Note that some filters have secondary children, namely blkverify (the
> image to be verified) and blklogwrites (the log).  This patch does not
> touch those children.
> 
> Note that for blkverify, the filtered child should not be format-probed.
> While there is nothing enforcing this here, in practice, it will not be:
> blkverify implements .bdrv_file_open.  The block layer ensures (and in
> fact, asserts) that BDRV_O_PROTOCOL is set for every BDS whose driver
> implements .bdrv_file_open.  This flag will then be bequeathed to
> blkverify's children, and they will thus (by default) not be probed
> either.
> 
> ("By default" refers to the fact that blkverify's other child (the
> non-filtered one) will have BDRV_O_PROTOCOL force-unset, because that is
> what happens for all non-filtered children of non-format drivers.)
> 
> Signed-off-by: Max Reitz <mreitz@redhat.com>
> ---
Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org



^ permalink raw reply	[flat|nested] 54+ messages in thread

* Re: [PATCH v4 27/34] block: Use child_of_bds in remaining places
  2020-05-13 11:05 ` [PATCH v4 27/34] block: Use child_of_bds in remaining places Max Reitz
@ 2020-05-13 21:08   ` Eric Blake
  0 siblings, 0 replies; 54+ messages in thread
From: Eric Blake @ 2020-05-13 21:08 UTC (permalink / raw)
  To: Max Reitz, qemu-block; +Cc: Kevin Wolf, qemu-devel

On 5/13/20 6:05 AM, Max Reitz wrote:
> Replace child_file by child_of_bds in all remaining places (excluding
> tests).
> 
> Signed-off-by: Max Reitz <mreitz@redhat.com>
> ---
>   block.c              |  3 ++-
>   block/backup-top.c   |  4 ++--
>   block/blklogwrites.c |  4 ++--
>   block/raw-format.c   | 15 +++++++++++++--
>   4 files changed, 19 insertions(+), 7 deletions(-)
> 

> @@ -448,8 +449,18 @@ static int raw_open(BlockDriverState *bs, QDict *options, int flags,
>           return ret;
>       }
>   
> -    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 0,
> -                               false, errp);
> +    /*
> +     * Without offset and a size limit, this driver behaves very much
> +     * like a filter.  With any such limit, it does not.
> +     */
> +    if (offset || has_size) {
> +        file_role = BDRV_CHILD_DATA | BDRV_CHILD_PRIMARY;
> +    } else {
> +        file_role = BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY;
> +    }

I wonder if we'll hit subtle bugs where one but not the other use of raw 
breaks because of the difference in roles.  I know we have _some_ iotest 
coverage of raw with offsets, but wonder if we might need more (or a way 
to add it on top of existing images, similar to how we can easily toggle 
qcow2 options like refcount size for interesting non-default test runs).

> +
> +    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_of_bds,
> +                               file_role, false, errp);
>       if (!bs->file) {
>           return -EINVAL;
>       }
> 

At any rate, if we have corner-case bugs, I don't think this is making 
them worse.
Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org



^ permalink raw reply	[flat|nested] 54+ messages in thread

* Re: [PATCH v4 32/34] block: Drop child_file
  2020-05-13 11:05 ` [PATCH v4 32/34] block: Drop child_file Max Reitz
@ 2020-05-13 21:11   ` Eric Blake
  0 siblings, 0 replies; 54+ messages in thread
From: Eric Blake @ 2020-05-13 21:11 UTC (permalink / raw)
  To: Max Reitz, qemu-block; +Cc: Kevin Wolf, qemu-devel

On 5/13/20 6:05 AM, Max Reitz wrote:
> Signed-off-by: Max Reitz <mreitz@redhat.com>
> ---
>   include/block/block_int.h |  1 -
>   block.c                   | 39 ++-------------------------------------
>   tests/test-bdrv-drain.c   |  8 +++-----
>   3 files changed, 5 insertions(+), 43 deletions(-)
> 

Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org



^ permalink raw reply	[flat|nested] 54+ messages in thread

* Re: [PATCH v4 33/34] block: Pass BdrvChildRole in remaining cases
  2020-05-13 11:05 ` [PATCH v4 33/34] block: Pass BdrvChildRole in remaining cases Max Reitz
@ 2020-05-13 21:12   ` Eric Blake
  0 siblings, 0 replies; 54+ messages in thread
From: Eric Blake @ 2020-05-13 21:12 UTC (permalink / raw)
  To: Max Reitz, qemu-block; +Cc: Kevin Wolf, qemu-devel

On 5/13/20 6:05 AM, Max Reitz wrote:
> These calls have no real use for the child role yet, but it will not
> harm to give one.
> 
> Notably, the bdrv_root_attach_child() call in blockjob.c is left
> unmodified because there is not much the generic BlockJob object wants
> from its children.
> 
> Signed-off-by: Max Reitz <mreitz@redhat.com>
> ---
>   block/block-backend.c | 11 +++++++----
>   block/vvfat.c         |  4 +++-
>   2 files changed, 10 insertions(+), 5 deletions(-)
> 

Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org



^ permalink raw reply	[flat|nested] 54+ messages in thread

* Re: [PATCH v4 34/34] block: Drop @child_class from bdrv_child_perm()
  2020-05-13 11:05 ` [PATCH v4 34/34] block: Drop @child_class from bdrv_child_perm() Max Reitz
@ 2020-05-13 21:15   ` Eric Blake
  0 siblings, 0 replies; 54+ messages in thread
From: Eric Blake @ 2020-05-13 21:15 UTC (permalink / raw)
  To: Max Reitz, qemu-block; +Cc: Kevin Wolf, qemu-devel

On 5/13/20 6:05 AM, Max Reitz wrote:
> Implementations should decide the necessary permissions based on @role.
> 
> Signed-off-by: Max Reitz <mreitz@redhat.com>
> ---

> +++ b/block.c
> @@ -1947,13 +1947,13 @@ bool bdrv_is_writable(BlockDriverState *bs)
>   }
>   
>   static void bdrv_child_perm(BlockDriverState *bs, BlockDriverState *child_bs,
> -                            BdrvChild *c, const BdrvChildClass *child_class,
> -                            BdrvChildRole role, BlockReopenQueue *reopen_queue,
> +                            BdrvChild *c, BdrvChildRole role,
> +                            BlockReopenQueue *reopen_queue,
>                               uint64_t parent_perm, uint64_t parent_shared,
>                               uint64_t *nperm, uint64_t *nshared)
>   {
>       assert(bs->drv && bs->drv->bdrv_child_perm);
> -    bs->drv->bdrv_child_perm(bs, c, child_class, role, reopen_queue,
> +    bs->drv->bdrv_child_perm(bs, c, role, reopen_queue,
>                                parent_perm, parent_shared,
>                                nperm, nshared);

Is it worth reflowing this call into two lines rather than three?  But 
that's cosmetic.

Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org



^ permalink raw reply	[flat|nested] 54+ messages in thread

* Re: [PATCH v4 00/34] block: Introduce real BdrvChildRole
  2020-05-13 11:05 [PATCH v4 00/34] block: Introduce real BdrvChildRole Max Reitz
                   ` (34 preceding siblings ...)
  2020-05-13 16:36 ` [PATCH v4 00/34] block: Introduce real BdrvChildRole Kevin Wolf
@ 2020-05-14 13:44 ` Kevin Wolf
  35 siblings, 0 replies; 54+ messages in thread
From: Kevin Wolf @ 2020-05-14 13:44 UTC (permalink / raw)
  To: Max Reitz; +Cc: qemu-devel, qemu-block

Am 13.05.2020 um 13:05 hat Max Reitz geschrieben:
> Based-on: <20200429141126.85159-1-mreitz@redhat.com>
> (“block: Do not call BlockDriver.bdrv_make_empty() directly”)
> 
> Branch: https://github.com/XanClic/qemu.git child-role-v4
> Branch: https://git.xanclic.moe/XanClic/qemu.git child-role-v4

Thanks, applied to the block branch (and squashed in Eric's English
corrections).

Kevin



^ permalink raw reply	[flat|nested] 54+ messages in thread

end of thread, other threads:[~2020-05-14 13:46 UTC | newest]

Thread overview: 54+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-05-13 11:05 [PATCH v4 00/34] block: Introduce real BdrvChildRole Max Reitz
2020-05-13 11:05 ` [PATCH v4 01/34] block: Mark commit, mirror, blkreplay as filters Max Reitz
2020-05-13 11:05 ` [PATCH v4 02/34] block: Add BlockDriver.is_format Max Reitz
2020-05-13 11:05 ` [PATCH v4 03/34] block: Rename BdrvChildRole to BdrvChildClass Max Reitz
2020-05-13 11:05 ` [PATCH v4 04/34] block: Add BdrvChildRole and BdrvChildRoleBits Max Reitz
2020-05-13 17:36   ` Eric Blake
2020-05-13 11:05 ` [PATCH v4 05/34] block: Add BdrvChildRole to BdrvChild Max Reitz
2020-05-13 11:05 ` [PATCH v4 06/34] block: Pass BdrvChildRole to bdrv_child_perm() Max Reitz
2020-05-13 11:05 ` [PATCH v4 07/34] block: Pass BdrvChildRole to .inherit_options() Max Reitz
2020-05-13 11:05 ` [PATCH v4 08/34] block: Pass parent_is_format " Max Reitz
2020-05-13 11:05 ` [PATCH v4 09/34] block: Rename bdrv_inherited_options() Max Reitz
2020-05-13 11:05 ` [PATCH v4 10/34] block: Add generic bdrv_inherited_options() Max Reitz
2020-05-13 20:13   ` Eric Blake
2020-05-13 11:05 ` [PATCH v4 11/34] block: Use bdrv_inherited_options() Max Reitz
2020-05-13 20:18   ` Eric Blake
2020-05-13 11:05 ` [PATCH v4 12/34] block: Unify bdrv_child_cb_attach() Max Reitz
2020-05-13 20:26   ` Eric Blake
2020-05-13 11:05 ` [PATCH v4 13/34] block: Unify bdrv_child_cb_detach() Max Reitz
2020-05-13 20:27   ` Eric Blake
2020-05-13 11:05 ` [PATCH v4 14/34] block: Add child_of_bds Max Reitz
2020-05-13 20:29   ` Eric Blake
2020-05-13 11:05 ` [PATCH v4 15/34] block: Distinguish paths in *_format_default_perms Max Reitz
2020-05-13 20:30   ` Eric Blake
2020-05-13 11:05 ` [PATCH v4 16/34] block: Pull out bdrv_default_perms_for_cow() Max Reitz
2020-05-13 20:33   ` Eric Blake
2020-05-13 11:05 ` [PATCH v4 17/34] block: Pull out bdrv_default_perms_for_storage() Max Reitz
2020-05-13 11:05 ` [PATCH v4 18/34] block: Relax *perms_for_storage for data children Max Reitz
2020-05-13 20:38   ` Eric Blake
2020-05-13 11:05 ` [PATCH v4 19/34] block: Add bdrv_default_perms() Max Reitz
2020-05-13 20:43   ` Eric Blake
2020-05-13 11:05 ` [PATCH v4 20/34] raw-format: Split raw_read_options() Max Reitz
2020-05-13 11:05 ` [PATCH v4 21/34] block: Switch child_format users to child_of_bds Max Reitz
2020-05-13 11:05 ` [PATCH v4 22/34] block: Drop child_format Max Reitz
2020-05-13 11:05 ` [PATCH v4 23/34] block: Make backing files child_of_bds children Max Reitz
2020-05-13 20:46   ` Eric Blake
2020-05-13 11:05 ` [PATCH v4 24/34] block: Drop child_backing Max Reitz
2020-05-13 20:47   ` Eric Blake
2020-05-13 11:05 ` [PATCH v4 25/34] block: Make format drivers use child_of_bds Max Reitz
2020-05-13 11:05 ` [PATCH v4 26/34] block: Make filter " Max Reitz
2020-05-13 21:02   ` Eric Blake
2020-05-13 11:05 ` [PATCH v4 27/34] block: Use child_of_bds in remaining places Max Reitz
2020-05-13 21:08   ` Eric Blake
2020-05-13 11:05 ` [PATCH v4 28/34] tests: Use child_of_bds instead of child_file Max Reitz
2020-05-13 11:05 ` [PATCH v4 29/34] block: Use bdrv_default_perms() Max Reitz
2020-05-13 11:05 ` [PATCH v4 30/34] block: Make bdrv_filter_default_perms() static Max Reitz
2020-05-13 11:05 ` [PATCH v4 31/34] block: Drop bdrv_format_default_perms() Max Reitz
2020-05-13 11:05 ` [PATCH v4 32/34] block: Drop child_file Max Reitz
2020-05-13 21:11   ` Eric Blake
2020-05-13 11:05 ` [PATCH v4 33/34] block: Pass BdrvChildRole in remaining cases Max Reitz
2020-05-13 21:12   ` Eric Blake
2020-05-13 11:05 ` [PATCH v4 34/34] block: Drop @child_class from bdrv_child_perm() Max Reitz
2020-05-13 21:15   ` Eric Blake
2020-05-13 16:36 ` [PATCH v4 00/34] block: Introduce real BdrvChildRole Kevin Wolf
2020-05-14 13:44 ` Kevin Wolf

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