[Qemu-block] [PATCH v2 1/2] block: Fix flags in reopen queue

[Fam Zheng]

Reopen flags are not synchronized according to the
bdrv_reopen_queue_child precedence until bdrv_reopen_prepare. It is a
bit too late: we already check the consistency in bdrv_check_perm before
that.

This fixes the bug that when bdrv_reopen a RO node as RW, the flags for
backing child are wrong. Before, we could recurse with flags.rw=1; now,
role->inherit_options + update_flags_from_options will make sure to
clear the bit when necessary.  Note that this will not clear an
explicitly set bit, as in the case of parallel block jobs (e.g.
test_stream_parallel in 030), because the explicit options include
'read-only=false' (for an intermediate node used by a different job).

Signed-off-by: Fam Zheng <address@hidden>
---
 block.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/block.c b/block.c
index 75a9fd49de..a121d2ebcc 100644
--- a/block.c
+++ b/block.c
@@ -2883,8 +2883,15 @@ static BlockReopenQueue 
*bdrv_reopen_queue_child(BlockReopenQueue *bs_queue,
 
     /* Inherit from parent node */
     if (parent_options) {
+        QemuOpts *opts;
+        QDict *options_copy;
         assert(!flags);
         role->inherit_options(&flags, options, parent_flags, parent_options);
+        options_copy = qdict_clone_shallow(options);
+        opts = qemu_opts_create(&bdrv_runtime_opts, NULL, 0, &error_abort);
+        qemu_opts_absorb_qdict(opts, options_copy, NULL);
+        update_flags_from_options(&flags, opts);
+        qemu_opts_del(opts);
     }
 
     /* Old values are used for options that aren't set yet */
-- 
2.14.3