diff options
| -rw-r--r-- | block.c | 68 |
1 files changed, 43 insertions, 25 deletions
diff --git a/block.c b/block.c index dc43e36f69..c7409cf658 100644 --- a/block.c +++ b/block.c @@ -5412,6 +5412,9 @@ bdrv_replace_node_noperm(BlockDriverState *from, } /* + * Switch all parents of @from to point to @to instead. @from and @to must be in + * the same AioContext and both must be drained. + * * With auto_skip=true bdrv_replace_node_common skips updating from parents * if it creates a parent-child relation loop or if parent is block-job. * @@ -5421,10 +5424,9 @@ bdrv_replace_node_noperm(BlockDriverState *from, * With @detach_subchain=true @to must be in a backing chain of @from. In this * case backing link of the cow-parent of @to is removed. */ -static int bdrv_replace_node_common(BlockDriverState *from, - BlockDriverState *to, - bool auto_skip, bool detach_subchain, - Error **errp) +static int GRAPH_WRLOCK +bdrv_replace_node_common(BlockDriverState *from, BlockDriverState *to, + bool auto_skip, bool detach_subchain, Error **errp) { Transaction *tran = tran_new(); g_autoptr(GSList) refresh_list = NULL; @@ -5433,16 +5435,9 @@ static int bdrv_replace_node_common(BlockDriverState *from, GLOBAL_STATE_CODE(); - /* Make sure that @from doesn't go away until we have successfully attached - * all of its parents to @to. */ - bdrv_ref(from); - - assert(qemu_get_current_aio_context() == qemu_get_aio_context()); + assert(from->quiesce_counter); + assert(to->quiesce_counter); assert(bdrv_get_aio_context(from) == bdrv_get_aio_context(to)); - bdrv_drained_begin(from); - bdrv_drained_begin(to); - - bdrv_graph_wrlock(to); if (detach_subchain) { assert(bdrv_chain_contains(from, to)); @@ -5483,33 +5478,51 @@ static int bdrv_replace_node_common(BlockDriverState *from, out: tran_finalize(tran, ret); - bdrv_graph_wrunlock(); - - bdrv_drained_end(to); - bdrv_drained_end(from); - bdrv_unref(from); - return ret; } int bdrv_replace_node(BlockDriverState *from, BlockDriverState *to, Error **errp) { + int ret; + GLOBAL_STATE_CODE(); - return bdrv_replace_node_common(from, to, true, false, errp); + /* Make sure that @from doesn't go away until we have successfully attached + * all of its parents to @to. */ + bdrv_ref(from); + bdrv_drained_begin(from); + bdrv_drained_begin(to); + bdrv_graph_wrlock(to); + + ret = bdrv_replace_node_common(from, to, true, false, errp); + + bdrv_graph_wrunlock(); + bdrv_drained_end(to); + bdrv_drained_end(from); + bdrv_unref(from); + + return ret; } int bdrv_drop_filter(BlockDriverState *bs, Error **errp) { BlockDriverState *child_bs; + int ret; GLOBAL_STATE_CODE(); + bdrv_graph_rdlock_main_loop(); child_bs = bdrv_filter_or_cow_bs(bs); bdrv_graph_rdunlock_main_loop(); - return bdrv_replace_node_common(bs, child_bs, true, true, errp); + bdrv_drained_begin(child_bs); + bdrv_graph_wrlock(bs); + ret = bdrv_replace_node_common(bs, child_bs, true, true, errp); + bdrv_graph_wrunlock(); + bdrv_drained_end(child_bs); + + return ret; } /* @@ -5957,15 +5970,15 @@ int bdrv_drop_intermediate(BlockDriverState *top, BlockDriverState *base, bdrv_ref(top); bdrv_drained_begin(base); - bdrv_graph_rdlock_main_loop(); + bdrv_graph_wrlock(base); if (!top->drv || !base->drv) { - goto exit; + goto exit_wrlock; } /* Make sure that base is in the backing chain of top */ if (!bdrv_chain_contains(top, base)) { - goto exit; + goto exit_wrlock; } /* If 'base' recursively inherits from 'top' then we should set @@ -5997,6 +6010,8 @@ int bdrv_drop_intermediate(BlockDriverState *top, BlockDriverState *base, * That's a FIXME. */ bdrv_replace_node_common(top, base, false, false, &local_err); + bdrv_graph_wrunlock(); + if (local_err) { error_report_err(local_err); goto exit; @@ -6029,8 +6044,11 @@ int bdrv_drop_intermediate(BlockDriverState *top, BlockDriverState *base, } ret = 0; + goto exit; + +exit_wrlock: + bdrv_graph_wrunlock(); exit: - bdrv_graph_rdunlock_main_loop(); bdrv_drained_end(base); bdrv_unref(top); return ret; |