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block: Remove BlockDriverState.blk 

This patch removes the remaining users of bs->blk, which will allow us
to have multiple BBs on top of a single BDS. In the meantime, all checks
that are currently in place to prevent the user from creating such
setups can be switched to bdrv_has_blk() instead of accessing BDS.blk.

Future patches can allow them and e.g. enable users to mirror to a block
device that already has a BlockBackend on it.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
This commit is contained in:
Kevin Wolf 2016-03-22 18:38:44 +01:00
parent 79c719b755
commit 1f0c461b82
5 changed files with 12 additions and 29 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
block.c
View File

@ -2226,14 +2226,6 @@ static void change_parent_backing_link(BlockDriverState *from,
{
BdrvChild *c, *next;
if (from->blk) {
/* FIXME We bypass blk_set_bs(), so we need to make these updates
* manually. The root problem is not in this change function, but the
* existence of BlockDriverState.blk. */
to->blk = from->blk;
from->blk = NULL;
}
QLIST_FOREACH_SAFE(c, &from->parents, next_parent, next) {
assert(c->role != &child_backing);
c->bs = to;
@ -2875,7 +2867,7 @@ const char *bdrv_get_node_name(const BlockDriverState *bs)
return bs->node_name;
}
static const char *bdrv_get_parent_name(const BlockDriverState *bs)
const char *bdrv_get_parent_name(const BlockDriverState *bs)
{
BdrvChild *c;
const char *name;

8
block/block-backend.c
View File

@ -152,7 +152,6 @@ BlockBackend *blk_new_with_bs(Error **errp)
bs = bdrv_new_root();
blk->root = bdrv_root_attach_child(bs, "root", &child_root);
blk->root->opaque = blk;
bs->blk = blk;
return blk;
}
@ -422,12 +421,10 @@ static BlockBackend *bdrv_first_blk(BlockDriverState *bs)
BdrvChild *child;
QLIST_FOREACH(child, &bs->parents, next_parent) {
if (child->role == &child_root) {
assert(bs->blk);
return child->opaque;
}
}
assert(!bs->blk);
return NULL;
}
@ -495,8 +492,6 @@ BlockBackend *blk_by_public(BlockBackendPublic *public)
*/
void blk_remove_bs(BlockBackend *blk)
{
assert(blk->root->bs->blk == blk);
notifier_list_notify(&blk->remove_bs_notifiers, blk);
if (blk->public.throttle_state) {
throttle_timers_detach_aio_context(&blk->public.throttle_timers);
@ -504,7 +499,6 @@ void blk_remove_bs(BlockBackend *blk)
blk_update_root_state(blk);
blk->root->bs->blk = NULL;
bdrv_root_unref_child(blk->root);
blk->root = NULL;
}
@ -514,11 +508,9 @@ void blk_remove_bs(BlockBackend *blk)
*/
void blk_insert_bs(BlockBackend *blk, BlockDriverState *bs)
{
assert(!blk->root && !bs->blk);
bdrv_ref(bs);
blk->root = bdrv_root_attach_child(bs, "root", &child_root);
blk->root->opaque = blk;
bs->blk = blk;
notifier_list_notify(&blk->insert_bs_notifiers, blk);
if (blk->public.throttle_state) {

4
block/mirror.c
View File

@ -468,7 +468,7 @@ static void mirror_exit(BlockJob *job, void *opaque)
/* This was checked in mirror_start_job(), but meanwhile one of the
* nodes could have been newly attached to a BlockBackend. */
if (to_replace->blk && s->target->blk) {
if (bdrv_has_blk(to_replace) && bdrv_has_blk(s->target)) {
error_report("block job: Can't create node with two BlockBackends");
data->ret = -EINVAL;
goto out;
@ -831,7 +831,7 @@ static void mirror_start_job(BlockDriverState *bs, BlockDriverState *target,
} else {
replaced_bs = bs;
}
if (replaced_bs->blk && target->blk) {
if (bdrv_has_blk(replaced_bs) && bdrv_has_blk(target)) {
error_setg(errp, "Can't create node with two BlockBackends");
return;
}

16
blockdev.c
View File

@ -1776,9 +1776,9 @@ static void external_snapshot_prepare(BlkActionState *common,
return;
}
if (state->new_bs->blk != NULL) {
if (bdrv_has_blk(state->new_bs)) {
error_setg(errp, "The snapshot is already in use by %s",
blk_name(state->new_bs->blk));
bdrv_get_parent_name(state->new_bs));
return;
}
@ -2494,9 +2494,9 @@ void qmp_x_blockdev_insert_medium(const char *device, const char *node_name,
return;
}
if (bs->blk) {
if (bdrv_has_blk(bs)) {
error_setg(errp, "Node '%s' is already in use by '%s'", node_name,
blk_name(bs->blk));
bdrv_get_parent_name(bs));
return;
}
@ -3441,7 +3441,7 @@ static void blockdev_mirror_common(BlockDriverState *bs,
if (bdrv_op_is_blocked(target, BLOCK_OP_TYPE_MIRROR_TARGET, errp)) {
return;
}
if (target->blk) {
if (bdrv_has_blk(target)) {
error_setg(errp, "Cannot mirror to an attached block device");
return;
}
@ -4030,15 +4030,15 @@ void qmp_x_blockdev_del(bool has_id, const char *id,
bs = blk_bs(blk);
aio_context = blk_get_aio_context(blk);
} else {
blk = NULL;
bs = bdrv_find_node(node_name);
if (!bs) {
error_setg(errp, "Cannot find node %s", node_name);
return;
}
blk = bs->blk;
if (blk) {
if (bdrv_has_blk(bs)) {
error_setg(errp, "Node %s is in use by %s",
node_name, blk_name(blk));
node_name, bdrv_get_parent_name(bs));
return;
}
aio_context = bdrv_get_aio_context(bs);

3
include/block/block_int.h
View File

@ -418,8 +418,6 @@ struct BlockDriverState {
BlockDriver *drv; /* NULL means no media */
void *opaque;
BlockBackend *blk; /* owning backend, if any */
AioContext *aio_context; /* event loop used for fd handlers, timers, etc */
/* long-running tasks intended to always use the same AioContext as this
* BDS may register themselves in this list to be notified of changes
@ -724,6 +722,7 @@ BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs,
const BdrvChildRole *child_role);
void bdrv_root_unref_child(BdrvChild *child);
const char *bdrv_get_parent_name(const BlockDriverState *bs);
void blk_dev_change_media_cb(BlockBackend *blk, bool load);
bool blk_dev_has_removable_media(BlockBackend *blk);
bool blk_dev_has_tray(BlockBackend *blk);