Am 17.03.2021 um 15:35 hat Vladimir Sementsov-Ogievskiy geschrieben: > Split out no-perm part of bdrv_root_attach_child() into separate > transaction action. bdrv_root_attach_child() now moves to new > permission update paradigm: first update graph relations then update > permissions. > > Signed-off-by: Vladimir Sementsov-Ogievskiy <[email protected]> > --- > block.c | 189 ++++++++++++++++++++++++++++++++++++++++---------------- > 1 file changed, 135 insertions(+), 54 deletions(-) > > diff --git a/block.c b/block.c > index 98ff44dbf7..b6bdc534d2 100644 > --- a/block.c > +++ b/block.c > @@ -2921,37 +2921,73 @@ static void bdrv_replace_child(BdrvChild *child, > BlockDriverState *new_bs) > } > } > > -/* > - * This function steals the reference to child_bs from the caller. > - * That reference is later dropped by bdrv_root_unref_child(). > - * > - * 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 BdrvChildClass *child_class, > - BdrvChildRole child_role, > - uint64_t perm, uint64_t shared_perm, > - void *opaque, Error **errp) > +static void bdrv_remove_empty_child(BdrvChild *child) > { > - BdrvChild *child; > - Error *local_err = NULL; > - int ret; > - AioContext *ctx; > + assert(!child->bs); > + QLIST_SAFE_REMOVE(child, next); > + g_free(child->name); > + g_free(child); > +} > > - ret = bdrv_check_update_perm(child_bs, NULL, perm, shared_perm, NULL, > errp); > - if (ret < 0) { > - bdrv_abort_perm_update(child_bs); > - bdrv_unref(child_bs); > - return NULL; > +typedef struct BdrvAttachChildCommonState { > + BdrvChild **child; > + AioContext *old_parent_ctx; > + AioContext *old_child_ctx; > +} BdrvAttachChildCommonState; > + > +static void bdrv_attach_child_common_abort(void *opaque) > +{ > + BdrvAttachChildCommonState *s = opaque; > + BdrvChild *child = *s->child; > + BlockDriverState *bs = child->bs; > + > + bdrv_replace_child_noperm(child, NULL); > + > + if (bdrv_get_aio_context(bs) != s->old_child_ctx) { > + bdrv_try_set_aio_context(bs, s->old_child_ctx, &error_abort); > } > > - child = g_new(BdrvChild, 1); > - *child = (BdrvChild) { > + if (bdrv_child_get_parent_aio_context(child) != s->old_parent_ctx) { > + GSList *ignore = g_slist_prepend(NULL, child); > + > + child->klass->can_set_aio_ctx(child, s->old_parent_ctx, &ignore, > + &error_abort); > + g_slist_free(ignore); > + ignore = g_slist_prepend(NULL, child); > + child->klass->set_aio_ctx(child, s->old_parent_ctx, &ignore); > + > + g_slist_free(ignore); > + } > + > + bdrv_unref(bs); > + bdrv_remove_empty_child(child); > + *s->child = NULL; > +} > + > +static TransactionActionDrv bdrv_attach_child_common_drv = { > + .abort = bdrv_attach_child_common_abort, > +}; > + > +/* > + * Common part of attoching bdrv child to bs or to blk or to job > + */ > +static int bdrv_attach_child_common(BlockDriverState *child_bs, > + const char *child_name, > + const BdrvChildClass *child_class, > + BdrvChildRole child_role, > + uint64_t perm, uint64_t shared_perm, > + void *opaque, BdrvChild **child, > + Transaction *tran, Error **errp) > +{ > + BdrvChild *new_child; > + AioContext *parent_ctx; > + AioContext *child_ctx = bdrv_get_aio_context(child_bs); > + > + assert(child); > + assert(*child == NULL); > + > + new_child = g_new(BdrvChild, 1); > + *new_child = (BdrvChild) { > .bs = NULL, > .name = g_strdup(child_name), > .klass = child_class, > @@ -2961,37 +2997,92 @@ BdrvChild *bdrv_root_attach_child(BlockDriverState > *child_bs, > .opaque = opaque, > }; > > - ctx = bdrv_child_get_parent_aio_context(child); > - > - /* If the AioContexts don't match, first try to move the subtree of > + /* > + * 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); > + * try moving the parent into the AioContext of child_bs instead. > + */ > + parent_ctx = bdrv_child_get_parent_aio_context(new_child); > + if (child_ctx != parent_ctx) { > + Error *local_err = NULL; > + int ret = bdrv_try_set_aio_context(child_bs, parent_ctx, &local_err); > + > if (ret < 0 && child_class->can_set_aio_ctx) { > - GSList *ignore = g_slist_prepend(NULL, child); > - ctx = bdrv_get_aio_context(child_bs); > - if (child_class->can_set_aio_ctx(child, ctx, &ignore, NULL)) { > + GSList *ignore = g_slist_prepend(NULL, new_child); > + if (child_class->can_set_aio_ctx(new_child, child_ctx, &ignore, > + NULL)) > + { > error_free(local_err); > ret = 0; > g_slist_free(ignore); > - ignore = g_slist_prepend(NULL, child); > - child_class->set_aio_ctx(child, ctx, &ignore); > + ignore = g_slist_prepend(NULL, new_child); > + child_class->set_aio_ctx(new_child, child_ctx, &ignore); > } > g_slist_free(ignore); > } > + > if (ret < 0) { > error_propagate(errp, local_err); > - g_free(child); > - bdrv_abort_perm_update(child_bs); > - bdrv_unref(child_bs); > - return NULL; > + bdrv_remove_empty_child(new_child); > + return ret; > } > } > > - /* This performs the matching bdrv_set_perm() for the above check. */ > - bdrv_replace_child(child, child_bs); > + bdrv_ref(child_bs); > + bdrv_replace_child_noperm(new_child, child_bs); > + > + *child = new_child; > > + BdrvAttachChildCommonState *s = g_new(BdrvAttachChildCommonState, 1); > + *s = (BdrvAttachChildCommonState) { > + .child = child, > + .old_parent_ctx = parent_ctx, > + .old_child_ctx = child_ctx, > + }; > + tran_add(tran, &bdrv_attach_child_common_drv, s);
Who frees s? Should bdrv_attach_child_common_drv have a .clean? > + > + return 0; > +} Kevin
