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[PATCH 09/22] quorum: Add QuorumChild.to_be_replaced
From: |
Max Reitz |
Subject: |
[PATCH 09/22] quorum: Add QuorumChild.to_be_replaced |
Date: |
Fri, 20 Sep 2019 17:27:51 +0200 |
We will need this to verify that Quorum can let one of its children be
replaced without breaking anything else.
Signed-off-by: Max Reitz <address@hidden>
---
block/quorum.c | 23 +++++++++++++++++++++++
1 file changed, 23 insertions(+)
diff --git a/block/quorum.c b/block/quorum.c
index cf2171cc74..207054a64e 100644
--- a/block/quorum.c
+++ b/block/quorum.c
@@ -67,6 +67,13 @@ typedef struct QuorumVotes {
typedef struct QuorumChild {
BdrvChild *child;
+
+ /*
+ * If set, check whether this node can be replaced without any
+ * other parent noticing: Unshare CONSISTENT_READ, and take the
+ * WRITE permission.
+ */
+ bool to_be_replaced;
} QuorumChild;
/* the following structure holds the state of one quorum instance */
@@ -1128,6 +1135,16 @@ static void quorum_child_perm(BlockDriverState *bs,
BdrvChild *c,
uint64_t perm, uint64_t shared,
uint64_t *nperm, uint64_t *nshared)
{
+ BDRVQuorumState *s = bs->opaque;
+ int i;
+
+ for (i = 0; i < s->num_children; i++) {
+ if (s->children[i].child == c) {
+ break;
+ }
+ }
+ assert(!c || i < s->num_children);
+
*nperm = perm & DEFAULT_PERM_PASSTHROUGH;
/*
@@ -1137,6 +1154,12 @@ static void quorum_child_perm(BlockDriverState *bs,
BdrvChild *c,
*nshared = (shared & (BLK_PERM_CONSISTENT_READ |
BLK_PERM_WRITE_UNCHANGED))
| DEFAULT_PERM_UNCHANGED;
+
+ if (c && s->children[i].to_be_replaced) {
+ /* Prepare for sudden data changes */
+ *nperm |= BLK_PERM_WRITE;
+ *nshared &= ~BLK_PERM_CONSISTENT_READ;
+ }
}
static const char *const quorum_strong_runtime_opts[] = {
--
2.21.0
- [PATCH 03/22] block: Drop bdrv_is_first_non_filter(), (continued)
- [PATCH 03/22] block: Drop bdrv_is_first_non_filter(), Max Reitz, 2019/09/20
- [PATCH 04/22] iotests: Let 041 use -blockdev for quorum children, Max Reitz, 2019/09/20
- [PATCH 05/22] quorum: Fix child permissions, Max Reitz, 2019/09/20
- [PATCH 07/22] blkverify: Implement .bdrv_recurse_can_replace(), Max Reitz, 2019/09/20
- [PATCH 09/22] quorum: Add QuorumChild.to_be_replaced,
Max Reitz <=
- [PATCH 06/22] block: Add bdrv_recurse_can_replace(), Max Reitz, 2019/09/20
- [PATCH 08/22] quorum: Store children in own structure, Max Reitz, 2019/09/20
- [PATCH 12/22] block: Remove bdrv_recurse_is_first_non_filter(), Max Reitz, 2019/09/20