From: Kevin Wolf <kw...@redhat.com> This allows us to detect errors in cache flushing (ENOMEDIUM) without choking on a null dereference because we assume that blk_bs(bb) is always defined.
Signed-off-by: Kevin Wolf <kw...@redhat.com> Signed-off-by: John Snow <js...@redhat.com> --- block.c | 2 +- block/block-backend.c | 40 ++++++++++++++++++++++++++++++++++------ 2 files changed, 35 insertions(+), 7 deletions(-) diff --git a/block.c b/block.c index ce9cce7..834b836 100644 --- a/block.c +++ b/block.c @@ -4476,7 +4476,7 @@ out: AioContext *bdrv_get_aio_context(BlockDriverState *bs) { - return bs->aio_context; + return bs ? bs->aio_context : qemu_get_aio_context(); } void bdrv_coroutine_enter(BlockDriverState *bs, Coroutine *co) diff --git a/block/block-backend.c b/block/block-backend.c index 968438c..efd7e92 100644 --- a/block/block-backend.c +++ b/block/block-backend.c @@ -68,6 +68,9 @@ struct BlockBackend { NotifierList remove_bs_notifiers, insert_bs_notifiers; int quiesce_counter; + + /* Number of in-flight requests. Accessed with atomic ops. */ + unsigned int in_flight; }; typedef struct BlockBackendAIOCB { @@ -1109,6 +1112,16 @@ int blk_make_zero(BlockBackend *blk, BdrvRequestFlags flags) return bdrv_make_zero(blk->root, flags); } +static void blk_inc_in_flight(BlockBackend *blk) +{ + atomic_inc(&blk->in_flight); +} + +static void blk_dec_in_flight(BlockBackend *blk) +{ + atomic_dec(&blk->in_flight); +} + static void error_callback_bh(void *opaque) { struct BlockBackendAIOCB *acb = opaque; @@ -1147,7 +1160,7 @@ static const AIOCBInfo blk_aio_em_aiocb_info = { static void blk_aio_complete(BlkAioEmAIOCB *acb) { if (acb->has_returned) { - bdrv_dec_in_flight(acb->common.bs); + blk_dec_in_flight(acb->rwco.blk); acb->common.cb(acb->common.opaque, acb->rwco.ret); qemu_aio_unref(acb); } @@ -1168,7 +1181,7 @@ static BlockAIOCB *blk_aio_prwv(BlockBackend *blk, int64_t offset, int bytes, BlkAioEmAIOCB *acb; Coroutine *co; - bdrv_inc_in_flight(blk_bs(blk)); + blk_inc_in_flight(blk); acb = blk_aio_get(&blk_aio_em_aiocb_info, blk, cb, opaque); acb->rwco = (BlkRwCo) { .blk = blk, @@ -1405,14 +1418,28 @@ int blk_flush(BlockBackend *blk) void blk_drain(BlockBackend *blk) { - if (blk_bs(blk)) { - bdrv_drain(blk_bs(blk)); + AioContext *ctx = blk_get_aio_context(blk); + + while (atomic_read(&blk->in_flight)) { + aio_context_acquire(ctx); + aio_poll(ctx, false); + aio_context_release(ctx); + + if (blk_bs(blk)) { + bdrv_drain(blk_bs(blk)); + } } } void blk_drain_all(void) { - bdrv_drain_all(); + BlockBackend *blk = NULL; + + bdrv_drain_all_begin(); + while ((blk = blk_all_next(blk)) != NULL) { + blk_drain(blk); + } + bdrv_drain_all_end(); } void blk_set_on_error(BlockBackend *blk, BlockdevOnError on_read_error, @@ -1453,10 +1480,11 @@ static void send_qmp_error_event(BlockBackend *blk, bool is_read, int error) { IoOperationType optype; + BlockDriverState *bs = blk_bs(blk); optype = is_read ? IO_OPERATION_TYPE_READ : IO_OPERATION_TYPE_WRITE; qapi_event_send_block_io_error(blk_name(blk), - bdrv_get_node_name(blk_bs(blk)), optype, + bs ? bdrv_get_node_name(bs) : "", optype, action, blk_iostatus_is_enabled(blk), error == ENOSPC, strerror(error), &error_abort); -- 2.9.4