Quorum cannot share WRITE or RESIZE on its children. Presumably, it
only does so because as a filter, it seemed intuitively correct to point
its .bdrv_child_perm to bdrv_filter_default_perm().
However, it is not really a filter, and bdrv_filter_default_perm() does
not work for it, so we have to provide a custom .bdrv_child_perm
implementation.
Signed-off-by: Max Reitz
---
block/quorum.c | 19 ++-
1 file changed, 18 insertions(+), 1 deletion(-)
diff --git a/block/quorum.c b/block/quorum.c
index df68adcfaa..17b439056f 100644
--- a/block/quorum.c
+++ b/block/quorum.c
@@ -1114,6 +1114,23 @@ static char *quorum_dirname(BlockDriverState *bs, Error
**errp)
return NULL;
}
+static void quorum_child_perm(BlockDriverState *bs, BdrvChild *c,
+ const BdrvChildRole *role,
+ BlockReopenQueue *reopen_queue,
+ uint64_t perm, uint64_t shared,
+ uint64_t *nperm, uint64_t *nshared)
+{
+*nperm = perm & DEFAULT_PERM_PASSTHROUGH;
+
+/*
+ * We cannot share RESIZE or WRITE, as this would make the
+ * children differ from each other.
+ */
+*nshared = (shared & (BLK_PERM_CONSISTENT_READ |
+ BLK_PERM_WRITE_UNCHANGED))
+ | DEFAULT_PERM_UNCHANGED;
+}
+
static const char *const quorum_strong_runtime_opts[] = {
QUORUM_OPT_VOTE_THRESHOLD,
QUORUM_OPT_BLKVERIFY,
@@ -1143,7 +1160,7 @@ static BlockDriver bdrv_quorum = {
.bdrv_add_child = quorum_add_child,
.bdrv_del_child = quorum_del_child,
-.bdrv_child_perm= bdrv_filter_default_perms,
+.bdrv_child_perm= quorum_child_perm,
.is_filter = true,
.bdrv_recurse_is_first_non_filter = quorum_recurse_is_first_non_filter,
--
2.23.0
