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[PATCH for-5.0 v4 1/5] block: Add bdrv_qapi_perm_to_blk_perm()
From: |
Max Reitz |
Subject: |
[PATCH for-5.0 v4 1/5] block: Add bdrv_qapi_perm_to_blk_perm() |
Date: |
Fri, 8 Nov 2019 13:34:51 +0100 |
We need some way to correlate QAPI BlockPermission values with
BLK_PERM_* flags. We could:
(1) have the same order in the QAPI definition as the the BLK_PERM_*
flags are in LSb-first order. However, then there is no guarantee
that they actually match (e.g. when someone modifies the QAPI schema
without thinking of the BLK_PERM_* definitions).
We could add static assertions, but these would break what’s good
about this solution, namely its simplicity.
(2) define the BLK_PERM_* flags based on the BlockPermission values.
But this way whenever someone were to modify the QAPI order
(perfectly sensible in theory), the BLK_PERM_* values would change.
Because these values are used for file locking, this might break
file locking between different qemu versions.
Therefore, go the slightly more cumbersome way: Add a function to
translate from the QAPI constants to the BLK_PERM_* flags.
Signed-off-by: Max Reitz <address@hidden>
---
block.c | 18 ++++++++++++++++++
include/block/block.h | 1 +
2 files changed, 19 insertions(+)
diff --git a/block.c b/block.c
index 4cffc2bc35..066433f3e2 100644
--- a/block.c
+++ b/block.c
@@ -2227,6 +2227,24 @@ void bdrv_format_default_perms(BlockDriverState *bs,
BdrvChild *c,
*nshared = shared;
}
+uint64_t bdrv_qapi_perm_to_blk_perm(BlockPermission qapi_perm)
+{
+ static const uint64_t permissions[] = {
+ [BLOCK_PERMISSION_CONSISTENT_READ] = BLK_PERM_CONSISTENT_READ,
+ [BLOCK_PERMISSION_WRITE] = BLK_PERM_WRITE,
+ [BLOCK_PERMISSION_WRITE_UNCHANGED] = BLK_PERM_WRITE_UNCHANGED,
+ [BLOCK_PERMISSION_RESIZE] = BLK_PERM_RESIZE,
+ [BLOCK_PERMISSION_GRAPH_MOD] = BLK_PERM_GRAPH_MOD,
+ };
+
+ QEMU_BUILD_BUG_ON(ARRAY_SIZE(permissions) != BLOCK_PERMISSION__MAX);
+ QEMU_BUILD_BUG_ON(1UL << ARRAY_SIZE(permissions) != BLK_PERM_ALL + 1);
+
+ assert(qapi_perm < BLOCK_PERMISSION__MAX);
+
+ return permissions[qapi_perm];
+}
+
static void bdrv_replace_child_noperm(BdrvChild *child,
BlockDriverState *new_bs)
{
diff --git a/include/block/block.h b/include/block/block.h
index 1df9848e74..e9dcfef7fa 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -280,6 +280,7 @@ enum {
};
char *bdrv_perm_names(uint64_t perm);
+uint64_t bdrv_qapi_perm_to_blk_perm(BlockPermission qapi_perm);
/* disk I/O throttling */
void bdrv_init(void);
--
2.23.0
- [PATCH for-5.0 v4 0/5] iotests: Test failing mirror complete, Max Reitz, 2019/11/08
- [PATCH for-5.0 v4 1/5] block: Add bdrv_qapi_perm_to_blk_perm(),
Max Reitz <=
- [PATCH for-5.0 v4 2/5] block: Use bdrv_qapi_perm_to_blk_perm(), Max Reitz, 2019/11/08
- [PATCH for-5.0 v4 3/5] blkdebug: Allow taking/unsharing permissions, Max Reitz, 2019/11/08
- [PATCH for-5.0 v4 4/5] iotests: Add @error to wait_until_completed, Max Reitz, 2019/11/08
- [PATCH for-5.0 v4 5/5] iotests: Add test for failing mirror complete, Max Reitz, 2019/11/08
- Re: [PATCH for-5.0 v4 0/5] iotests: Test failing mirror complete, Max Reitz, 2019/11/26