Re: [PATCH v2 06/15] block: Fix crash on block_resize on inactive node
On Thu, Jan 30, 2025 at 06:12:37PM +0100, Kevin Wolf wrote: > 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 > --- > block.c | 7 +++ > block/block-backend.c | 2 +- > 2 files changed, 8 insertions(+), 1 deletion(-) Reviewed-by: Stefan Hajnoczi signature.asc Description: PGP signature
Re: [PATCH v2 06/15] block: Fix crash on block_resize on inactive node
On Thu, Jan 30, 2025 at 06:12:37PM +0100, Kevin Wolf wrote: > 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 > --- > block.c | 7 +++ > block/block-backend.c | 2 +- > 2 files changed, 8 insertions(+), 1 deletion(-) Reviewed-by: Eric Blake -- Eric Blake, Principal Software Engineer Red Hat, Inc. Virtualization: qemu.org | libguestfs.org
[PATCH v2 06/15] block: Fix crash on block_resize on inactive node
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
---
block.c | 7 +++
block/block-backend.c | 2 +-
2 files changed, 8 insertions(+), 1 deletion(-)
diff --git a/block.c b/block.c
index be6b71c314..fa6198bca3 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 d093f01f89..cc6f58ae78 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
