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block: return status from bdrv_append and friends 

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 <vsementsov@virtuozzo.com>
Message-Id: <20210202124956.63146-2-vsementsov@virtuozzo.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
This commit is contained in:
Vladimir Sementsov-Ogievskiy 2021-02-02 15:49:43 +03:00 committed by Eric Blake
parent ca4bfec41d
commit a1e708fcda
2 changed files with 43 additions and 27 deletions
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58
block.c
View File

@ -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", &child_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;
}
/*
@ -4532,9 +4540,9 @@ 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;
@ -4556,11 +4564,13 @@ 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;
@ -4591,14 +4601,18 @@ static void bdrv_replace_node_common(BlockDriverState *from,
bdrv_set_perm(to);
ret = 0;
out:
g_slist_free(list);
bdrv_drained_end(from);
bdrv_unref(from);
return ret;
}
void bdrv_replace_node(BlockDriverState *from, BlockDriverState *to,
Error **errp)
int bdrv_replace_node(BlockDriverState *from, BlockDriverState *to,
Error **errp)
{
return bdrv_replace_node_common(from, to, true, errp);
}
@ -4619,28 +4633,30 @@ void bdrv_replace_node(BlockDriverState *from, BlockDriverState *to,
* parents of bs_top after bdrv_append() returns. If the caller needs to keep a
* reference of its own, it must call bdrv_ref().
*/
void bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top,
Error **errp)
int bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top,
Error **errp)
{
Error *local_err = NULL;
bdrv_set_backing_hd(bs_new, bs_top, &local_err);
if (local_err) {
error_propagate(errp, local_err);
int ret = bdrv_set_backing_hd(bs_new, bs_top, errp);
if (ret < 0) {
goto out;
}
bdrv_replace_node(bs_top, bs_new, &local_err);
if (local_err) {
error_propagate(errp, local_err);
ret = bdrv_replace_node(bs_top, bs_new, errp);
if (ret < 0) {
bdrv_set_backing_hd(bs_new, NULL, &error_abort);
goto out;
}
/* bs_new is now referenced by its new parents, we don't need the
* additional reference any more. */
ret = 0;
out:
/*
* bs_new is now referenced by its new parents, we don't need the
* additional reference any more.
*/
bdrv_unref(bs_new);
return ret;
}
static void bdrv_delete(BlockDriverState *bs)

12
include/block/block.h
View File

@ -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,