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[PULL 16/51] block: Add BdrvChildRole and BdrvChildRoleBits
From: |
Kevin Wolf |
Subject: |
[PULL 16/51] block: Add BdrvChildRole and BdrvChildRoleBits |
Date: |
Fri, 15 May 2020 14:44:46 +0200 |
From: Max Reitz <address@hidden>
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 <address@hidden>
Message-Id: <address@hidden>
Reviewed-by: Eric Blake <address@hidden>
Signed-off-by: Kevin Wolf <address@hidden>
---
include/block/block.h | 56 +++++++++++++++++++++++++++++++++++++++++++
1 file changed, 56 insertions(+)
diff --git a/include/block/block.h b/include/block/block.h
index bc42e507bb..35f1a1cecf 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 that parent nodes assign to 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);
--
2.25.4
- [PULL 04/51] iotests: Mirror with different source/target size, (continued)
- [PULL 04/51] iotests: Mirror with different source/target size, Kevin Wolf, 2020/05/15
- [PULL 06/51] iotests: Fix incomplete type declarations, Kevin Wolf, 2020/05/15
- [PULL 08/51] block: Add bdrv_make_empty(), Kevin Wolf, 2020/05/15
- [PULL 09/51] block: Add blk_make_empty(), Kevin Wolf, 2020/05/15
- [PULL 10/51] block: Use blk_make_empty() after commits, Kevin Wolf, 2020/05/15
- [PULL 12/51] block: Use bdrv_make_empty() where possible, Kevin Wolf, 2020/05/15
- [PULL 07/51] iotests: Run pylint and mypy in a testcase, Kevin Wolf, 2020/05/15
- [PULL 11/51] replication: Avoid blk_make_empty() on read-only child, Kevin Wolf, 2020/05/15
- [PULL 13/51] block: Mark commit, mirror, blkreplay as filters, Kevin Wolf, 2020/05/15
- [PULL 15/51] block: Rename BdrvChildRole to BdrvChildClass, Kevin Wolf, 2020/05/15
- [PULL 16/51] block: Add BdrvChildRole and BdrvChildRoleBits,
Kevin Wolf <=
- [PULL 17/51] block: Add BdrvChildRole to BdrvChild, Kevin Wolf, 2020/05/15
- [PULL 19/51] block: Pass BdrvChildRole to .inherit_options(), Kevin Wolf, 2020/05/15
- [PULL 14/51] block: Add BlockDriver.is_format, Kevin Wolf, 2020/05/15
- [PULL 22/51] block: Add generic bdrv_inherited_options(), Kevin Wolf, 2020/05/15
- [PULL 23/51] block: Use bdrv_inherited_options(), Kevin Wolf, 2020/05/15
- [PULL 20/51] block: Pass parent_is_format to .inherit_options(), Kevin Wolf, 2020/05/15
- [PULL 18/51] block: Pass BdrvChildRole to bdrv_child_perm(), Kevin Wolf, 2020/05/15
- [PULL 25/51] block: Unify bdrv_child_cb_detach(), Kevin Wolf, 2020/05/15
- [PULL 28/51] block: Pull out bdrv_default_perms_for_cow(), Kevin Wolf, 2020/05/15
- [PULL 27/51] block: Distinguish paths in *_format_default_perms, Kevin Wolf, 2020/05/15