diff options
Diffstat (limited to 'block.c')
| -rw-r--r-- | block.c | 92 |
1 files changed, 92 insertions, 0 deletions
@@ -936,6 +936,13 @@ static int bdrv_child_cb_inactivate(BdrvChild *child) return 0; } +static bool bdrv_child_cb_can_set_aio_ctx(BdrvChild *child, AioContext *ctx, + GSList **ignore, Error **errp) +{ + BlockDriverState *bs = child->opaque; + return bdrv_can_set_aio_context(bs, ctx, ignore, errp); +} + /* * Returns the options and flags that a temporary snapshot should get, based on * the originally requested flags (the originally requested image will have @@ -1003,6 +1010,7 @@ const BdrvChildRole child_file = { .attach = bdrv_child_cb_attach, .detach = bdrv_child_cb_detach, .inactivate = bdrv_child_cb_inactivate, + .can_set_aio_ctx = bdrv_child_cb_can_set_aio_ctx, }; /* @@ -1029,6 +1037,7 @@ const BdrvChildRole child_format = { .attach = bdrv_child_cb_attach, .detach = bdrv_child_cb_detach, .inactivate = bdrv_child_cb_inactivate, + .can_set_aio_ctx = bdrv_child_cb_can_set_aio_ctx, }; static void bdrv_backing_attach(BdrvChild *c) @@ -1152,6 +1161,7 @@ const BdrvChildRole child_backing = { .drained_end = bdrv_child_cb_drained_end, .inactivate = bdrv_child_cb_inactivate, .update_filename = bdrv_backing_update_filename, + .can_set_aio_ctx = bdrv_child_cb_can_set_aio_ctx, }; static int bdrv_open_flags(BlockDriverState *bs, int flags) @@ -5750,6 +5760,88 @@ void bdrv_set_aio_context(BlockDriverState *bs, AioContext *new_context) aio_context_release(new_context); } +static bool bdrv_parent_can_set_aio_context(BdrvChild *c, AioContext *ctx, + GSList **ignore, Error **errp) +{ + if (g_slist_find(*ignore, c)) { + return true; + } + *ignore = g_slist_prepend(*ignore, c); + + /* A BdrvChildRole that doesn't handle AioContext changes cannot + * tolerate any AioContext changes */ + if (!c->role->can_set_aio_ctx) { + char *user = bdrv_child_user_desc(c); + error_setg(errp, "Changing iothreads is not supported by %s", user); + g_free(user); + return false; + } + if (!c->role->can_set_aio_ctx(c, ctx, ignore, errp)) { + assert(!errp || *errp); + return false; + } + return true; +} + +bool bdrv_child_can_set_aio_context(BdrvChild *c, AioContext *ctx, + GSList **ignore, Error **errp) +{ + if (g_slist_find(*ignore, c)) { + return true; + } + *ignore = g_slist_prepend(*ignore, c); + return bdrv_can_set_aio_context(c->bs, ctx, ignore, errp); +} + +/* @ignore will accumulate all visited BdrvChild object. The caller is + * responsible for freeing the list afterwards. */ +bool bdrv_can_set_aio_context(BlockDriverState *bs, AioContext *ctx, + GSList **ignore, Error **errp) +{ + BdrvChild *c; + + if (bdrv_get_aio_context(bs) == ctx) { + return true; + } + + QLIST_FOREACH(c, &bs->parents, next_parent) { + if (!bdrv_parent_can_set_aio_context(c, ctx, ignore, errp)) { + return false; + } + } + QLIST_FOREACH(c, &bs->children, next) { + if (!bdrv_child_can_set_aio_context(c, ctx, ignore, errp)) { + return false; + } + } + + return true; +} + +int bdrv_child_try_set_aio_context(BlockDriverState *bs, AioContext *ctx, + BdrvChild *ignore_child, Error **errp) +{ + GSList *ignore; + bool ret; + + ignore = ignore_child ? g_slist_prepend(NULL, ignore_child) : NULL; + ret = bdrv_can_set_aio_context(bs, ctx, &ignore, errp); + g_slist_free(ignore); + + if (!ret) { + return -EPERM; + } + + bdrv_set_aio_context(bs, ctx); + return 0; +} + +int bdrv_try_set_aio_context(BlockDriverState *bs, AioContext *ctx, + Error **errp) +{ + return bdrv_child_try_set_aio_context(bs, ctx, NULL, errp); +} + void bdrv_add_aio_context_notifier(BlockDriverState *bs, void (*attached_aio_context)(AioContext *new_context, void *opaque), void (*detach_aio_context)(void *opaque), void *opaque) |