The recommended use of qemu error api assumes returning status together
with setting errp and avoid void functions with errp parameter. Let's
improve bdrv_append and some friends to reduce error-propagation
overhead in further patches.
Choose int return status, because bdrv_replace_node_common() has call
to bdrv_check_update_perm(), which reports int status, which seems
correct to propagate.
Signed-off-by: Vladimir Sementsov-Ogievskiy
---
include/block/block.h | 12 -
block.c | 58 +++
2 files changed, 43 insertions(+), 27 deletions(-)
diff --git a/include/block/block.h b/include/block/block.h
index 81fcaad5ac..da24192901 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -356,10 +356,10 @@ int bdrv_create(BlockDriver *drv, const char* filename,
int bdrv_create_file(const char *filename, QemuOpts *opts, Error **errp);
BlockDriverState *bdrv_new(void);
-void bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top,
- Error **errp);
-void bdrv_replace_node(BlockDriverState *from, BlockDriverState *to,
- Error **errp);
+int bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top,
+Error **errp);
+int bdrv_replace_node(BlockDriverState *from, BlockDriverState *to,
+ Error **errp);
BlockDriverState *bdrv_insert_node(BlockDriverState *bs, QDict *node_options,
int flags, Error **errp);
@@ -373,8 +373,8 @@ BdrvChild *bdrv_open_child(const char *filename,
BdrvChildRole child_role,
bool allow_none, Error **errp);
BlockDriverState *bdrv_open_blockdev_ref(BlockdevRef *ref, Error **errp);
-void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd,
- Error **errp);
+int bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd,
+Error **errp);
int bdrv_open_backing_file(BlockDriverState *bs, QDict *parent_options,
const char *bdref_key, Error **errp);
BlockDriverState *bdrv_open(const char *filename, const char *reference,
diff --git a/block.c b/block.c
index 91a66d4f3e..8a169641de 100644
--- a/block.c
+++ b/block.c
@@ -2827,14 +2827,15 @@ static BdrvChildRole bdrv_backing_role(BlockDriverState
*bs)
* Sets the bs->backing link of a BDS. A new reference is created; callers
* which don't need their own reference any more must call bdrv_unref().
*/
-void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd,
- Error **errp)
+int bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd,
+Error **errp)
{
+int ret = 0;
bool update_inherits_from = bdrv_chain_contains(bs, backing_hd) &&
bdrv_inherits_from_recursive(backing_hd, bs);
if (bdrv_is_backing_chain_frozen(bs, child_bs(bs->backing), errp)) {
-return;
+return -EPERM;
}
if (backing_hd) {
@@ -2853,15 +2854,22 @@ void bdrv_set_backing_hd(BlockDriverState *bs,
BlockDriverState *backing_hd,
bs->backing = bdrv_attach_child(bs, backing_hd, "backing", _of_bds,
bdrv_backing_role(bs), errp);
+if (!bs->backing) {
+ret = -EPERM;
+goto out;
+}
+
/* If backing_hd was already part of bs's backing chain, and
* inherits_from pointed recursively to bs then let's update it to
* point directly to bs (else it will become NULL). */
-if (bs->backing && update_inherits_from) {
+if (update_inherits_from) {
backing_hd->inherits_from = bs;
}
out:
bdrv_refresh_limits(bs, NULL);
+
+return ret;
}
/*
@@ -4533,9 +4541,9 @@ static bool should_update_child(BdrvChild *c,
BlockDriverState *to)
* With auto_skip=false the error is returned if from has a parent which should
* not be updated.
*/
-static void bdrv_replace_node_common(BlockDriverState *from,
- BlockDriverState *to,
- bool auto_skip, Error **errp)
+static int bdrv_replace_node_common(BlockDriverState *from,
+BlockDriverState *to,
+bool auto_skip, Error **errp)
{
BdrvChild *c, *next;
GSList *list = NULL, *p;
@@ -4557,11 +4565,13 @@ static void bdrv_replace_node_common(BlockDriverState
*from,
if (auto_skip) {
continue;
}
+ret = -EINVAL;
error_setg(errp, "Should not change '%s' link to '%s'",
c->name, from->node_name);
goto out;
}
if (c->frozen) {
+ret = -EPERM;
error_setg(errp, "Cannot change '%s' link to '%s'",
c->name, from->node_name);
goto out;
@@ -4592,14 +4602,18 @@
