From eed2b4b40553cae162407b375f18c935f5025c53 Mon Sep 17 00:00:00 2001
From: Kevin Wolf <kwolf@redhat.com>
Date: Tue, 4 Feb 2025 22:13:57 +0100
Subject: [PATCH 13/23] block: Fix crash on block_resize on inactive node
RH-Author: Kevin Wolf <kwolf@redhat.com>
RH-MergeRequest: 339: QMP command for block device reactivation after migration
RH-Jira: RHEL-54296 RHEL-78397
RH-Acked-by: Eric Blake <eblake@redhat.com>
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
RH-Commit: [12/22] e352c665f68a865859cc62fe1ed6e4044407b8e3 (kmwolf/centos-qemu-kvm)
In order for block_resize to fail gracefully on an inactive node instead
of crashing with an assertion failure in bdrv_co_write_req_prepare()
(called from bdrv_co_truncate()), we need to check for inactive nodes
also when they are attached as a root node and make sure that
BLK_PERM_RESIZE isn't among the permissions allowed for inactive nodes.
To this effect, don't enumerate the permissions that are incompatible
with inactive nodes any more, but allow only BLK_PERM_CONSISTENT_READ
for them.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Acked-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20250204211407.381505-7-kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
(cherry picked from commit 8c2c72a33581987af8d8c484d03af3cd69b9e10a)
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
block.c | 7 +++++++
block/block-backend.c | 2 +-
2 files changed, 8 insertions(+), 1 deletion(-)
diff --git a/block.c b/block.c
index 41e72e6965..bedd54deaa 100644
--- a/block.c
+++ b/block.c
@@ -3077,6 +3077,13 @@ bdrv_attach_child_common(BlockDriverState *child_bs,
assert(child_class->get_parent_desc);
GLOBAL_STATE_CODE();
+ if (bdrv_is_inactive(child_bs) && (perm & ~BLK_PERM_CONSISTENT_READ)) {
+ g_autofree char *perm_names = bdrv_perm_names(perm);
+ error_setg(errp, "Permission '%s' unavailable on inactive node",
+ perm_names);
+ return NULL;
+ }
+
new_child = g_new(BdrvChild, 1);
*new_child = (BdrvChild) {
.bs = NULL,
diff --git a/block/block-backend.c b/block/block-backend.c
index db6f9b92a3..356db1b703 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -253,7 +253,7 @@ static bool blk_can_inactivate(BlockBackend *blk)
* guest. For block job BBs that satisfy this, we can just allow
* it. This is the case for mirror job source, which is required
* by libvirt non-shared block migration. */
- if (!(blk->perm & (BLK_PERM_WRITE | BLK_PERM_WRITE_UNCHANGED))) {
+ if (!(blk->perm & ~BLK_PERM_CONSISTENT_READ)) {
return true;
}
--
2.48.1