From a1e708fcda5eab10c866a7d6a4fad4f80b69ad15 Mon Sep 17 00:00:00 2001 From: Vladimir Sementsov-Ogievskiy Date: Tue, 2 Feb 2021 15:49:43 +0300 Subject: 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 Message-Id: <20210202124956.63146-2-vsementsov@virtuozzo.com> Reviewed-by: Alberto Garcia Signed-off-by: Eric Blake --- block.c | 58 +++++++++++++++++++++++++++++++++++++--------------------- 1 file changed, 37 insertions(+), 21 deletions(-) (limited to 'block.c') diff --git a/block.c b/block.c index 4e52b1c..fdb0261 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", &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) -- cgit v1.1