diff options
Diffstat (limited to 'block.c')
| -rw-r--r-- | block.c | 35 |
1 files changed, 34 insertions, 1 deletions
@@ -2249,14 +2249,19 @@ static void bdrv_replace_child(BdrvChild *child, BlockDriverState *new_bs) * * On failure NULL is returned, errp is set and the reference to * child_bs is also dropped. + * + * The caller must hold the AioContext lock @child_bs, but not that of @ctx + * (unless @child_bs is already in @ctx). */ BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs, const char *child_name, const BdrvChildRole *child_role, + AioContext *ctx, uint64_t perm, uint64_t shared_perm, void *opaque, Error **errp) { BdrvChild *child; + Error *local_err = NULL; int ret; ret = bdrv_check_update_perm(child_bs, NULL, perm, shared_perm, NULL, errp); @@ -2276,6 +2281,31 @@ BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs, .opaque = opaque, }; + /* If the AioContexts don't match, first try to move the subtree of + * child_bs into the AioContext of the new parent. If this doesn't work, + * try moving the parent into the AioContext of child_bs instead. */ + if (bdrv_get_aio_context(child_bs) != ctx) { + ret = bdrv_try_set_aio_context(child_bs, ctx, &local_err); + if (ret < 0 && child_role->can_set_aio_ctx) { + GSList *ignore = g_slist_prepend(NULL, child);; + ctx = bdrv_get_aio_context(child_bs); + if (child_role->can_set_aio_ctx(child, ctx, &ignore, NULL)) { + error_free(local_err); + ret = 0; + g_slist_free(ignore); + ignore = g_slist_prepend(NULL, child);; + child_role->set_aio_ctx(child, ctx, &ignore); + } + g_slist_free(ignore); + } + if (ret < 0) { + error_propagate(errp, local_err); + g_free(child); + bdrv_abort_perm_update(child_bs); + return NULL; + } + } + /* This performs the matching bdrv_set_perm() for the above check. */ bdrv_replace_child(child, child_bs); @@ -2289,6 +2319,9 @@ BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs, * * On failure NULL is returned, errp is set and the reference to * child_bs is also dropped. + * + * If @parent_bs and @child_bs are in different AioContexts, the caller must + * hold the AioContext lock for @child_bs, but not for @parent_bs. */ BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs, BlockDriverState *child_bs, @@ -2302,11 +2335,11 @@ BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs, bdrv_get_cumulative_perm(parent_bs, &perm, &shared_perm); assert(parent_bs->drv); - assert(bdrv_get_aio_context(parent_bs) == bdrv_get_aio_context(child_bs)); bdrv_child_perm(parent_bs, child_bs, NULL, child_role, NULL, perm, shared_perm, &perm, &shared_perm); child = bdrv_root_attach_child(child_bs, child_name, child_role, + bdrv_get_aio_context(parent_bs), perm, shared_perm, parent_bs, errp); if (child == NULL) { return NULL; |