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[Qemu-block] [PATCH 16/54] block: Default .bdrv_child_perm() for filter
From: |
Kevin Wolf |
Subject: |
[Qemu-block] [PATCH 16/54] block: Default .bdrv_child_perm() for filter drivers |
Date: |
Tue, 21 Feb 2017 15:58:12 +0100 |
Most filters need permissions related to read and write for their
children, but only if the node has a parent that wants to use the same
operation on the filter. The same is true for resize.
This adds a default implementation that simply forwards all necessary
permissions to all children of the node and leaves the other permissions
unchanged.
Signed-off-by: Kevin Wolf <address@hidden>
---
block.c | 24 ++++++++++++++++++++++++
include/block/block_int.h | 8 ++++++++
2 files changed, 32 insertions(+)
diff --git a/block.c b/block.c
index 2a86781..523cbd3 100644
--- a/block.c
+++ b/block.c
@@ -1531,6 +1531,30 @@ int bdrv_child_try_set_perm(BdrvChild *c, uint64_t perm,
uint64_t shared,
return 0;
}
+#define DEFAULT_PERM_PASSTHROUGH (BLK_PERM_CONSISTENT_READ \
+ | BLK_PERM_WRITE \
+ | BLK_PERM_WRITE_UNCHANGED \
+ | BLK_PERM_RESIZE)
+#define DEFAULT_PERM_UNCHANGED (BLK_PERM_ALL & ~DEFAULT_PERM_PASSTHROUGH)
+
+void bdrv_filter_default_perms(BlockDriverState *bs, BdrvChild *c,
+ const BdrvChildRole *role,
+ uint64_t perm, uint64_t shared,
+ uint64_t *nperm, uint64_t *nshared)
+{
+ if (c == NULL) {
+ *nperm = 0;
+ *nshared = BLK_PERM_ALL;
+ return;
+ }
+
+ *nperm = (perm & DEFAULT_PERM_PASSTHROUGH) |
+ (c->perm & DEFAULT_PERM_UNCHANGED);
+ *nshared = (shared & DEFAULT_PERM_PASSTHROUGH) |
+ (c->shared_perm & DEFAULT_PERM_UNCHANGED);
+}
+
+
static void bdrv_replace_child(BdrvChild *child, BlockDriverState *new_bs)
{
BlockDriverState *old_bs = child->bs;
diff --git a/include/block/block_int.h b/include/block/block_int.h
index cef2b6e..17f4c2d 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -872,6 +872,14 @@ void bdrv_child_abort_perm_update(BdrvChild *c);
int bdrv_child_try_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared,
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 BdrvChildRole *role,
+ uint64_t perm, uint64_t shared,
+ uint64_t *nperm, uint64_t *nshared);
+
const char *bdrv_get_parent_name(const BlockDriverState *bs);
void blk_dev_change_media_cb(BlockBackend *blk, bool load);
--
1.8.3.1