diff options
| -rw-r--r-- | block/io.c | 41 |
1 files changed, 12 insertions, 29 deletions
diff --git a/block/io.c b/block/io.c index b75d68886a..983307cf03 100644 --- a/block/io.c +++ b/block/io.c @@ -377,6 +377,16 @@ void bdrv_drain(BlockDriverState *bs) bdrv_drained_end(bs); } +static void bdrv_drain_assert_idle(BlockDriverState *bs) +{ + BdrvChild *child, *next; + + assert(atomic_read(&bs->in_flight) == 0); + QLIST_FOREACH_SAFE(child, &bs->children, next, next) { + bdrv_drain_assert_idle(child->bs); + } +} + /* * Wait for pending requests to complete across all BlockDriverStates * @@ -391,11 +401,8 @@ void bdrv_drain(BlockDriverState *bs) */ void bdrv_drain_all_begin(void) { - /* Always run first iteration so any pending completion BHs run */ - bool waited = true; BlockDriverState *bs; BdrvNextIterator it; - GSList *aio_ctxs = NULL, *ctx; /* BDRV_POLL_WHILE() for a node can only be called from its own I/O thread * or the main loop AioContext. We potentially use BDRV_POLL_WHILE() on @@ -409,35 +416,11 @@ void bdrv_drain_all_begin(void) aio_context_acquire(aio_context); bdrv_do_drained_begin(bs, true, NULL); aio_context_release(aio_context); - - if (!g_slist_find(aio_ctxs, aio_context)) { - aio_ctxs = g_slist_prepend(aio_ctxs, aio_context); - } } - /* Note that completion of an asynchronous I/O operation can trigger any - * number of other I/O operations on other devices---for example a - * coroutine can submit an I/O request to another device in response to - * request completion. Therefore we must keep looping until there was no - * more activity rather than simply draining each device independently. - */ - while (waited) { - waited = false; - - for (ctx = aio_ctxs; ctx != NULL; ctx = ctx->next) { - AioContext *aio_context = ctx->data; - - aio_context_acquire(aio_context); - for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) { - if (aio_context == bdrv_get_aio_context(bs)) { - waited |= bdrv_drain_recurse(bs); - } - } - aio_context_release(aio_context); - } + for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) { + bdrv_drain_assert_idle(bs); } - - g_slist_free(aio_ctxs); } void bdrv_drain_all_end(void) |