Using bdrv_do_drained_begin_quiesce() in bdrv_child_cb_drained_begin() is not a good idea: the callback might be called when running a drain in a coroutine, and bdrv_drained_begin_poll() does not handle that case, resulting in assertion failure.
Instead, bdrv_do_drained_begin with no recursion and poll will accomplish the same thing (invoking bdrv_do_drained_begin_quiesce) but will firstly check if we are already in a coroutine, and exit from that via bdrv_co_yield_to_drain(). Signed-off-by: Emanuele Giuseppe Esposito <[email protected]> --- block.c | 2 +- block/io.c | 8 +++++++- include/block/block-io.h | 20 +++++++++++--------- 3 files changed, 19 insertions(+), 11 deletions(-) diff --git a/block.c b/block.c index 718e4cae8b..372f16f4a0 100644 --- a/block.c +++ b/block.c @@ -1211,7 +1211,7 @@ static char *bdrv_child_get_parent_desc(BdrvChild *c) static void bdrv_child_cb_drained_begin(BdrvChild *child) { BlockDriverState *bs = child->opaque; - bdrv_do_drained_begin_quiesce(bs, NULL, false); + bdrv_drained_begin_no_poll(bs); } static bool bdrv_child_cb_drained_poll(BdrvChild *child) diff --git a/block/io.c b/block/io.c index e446782ae0..e77861c464 100644 --- a/block/io.c +++ b/block/io.c @@ -523,7 +523,7 @@ static void coroutine_fn bdrv_co_yield_to_drain(BlockDriverState *bs, } } -void bdrv_do_drained_begin_quiesce(BlockDriverState *bs, +static void bdrv_do_drained_begin_quiesce(BlockDriverState *bs, BdrvChild *parent, bool ignore_bds_parents) { IO_OR_GS_CODE(); @@ -587,6 +587,12 @@ void bdrv_subtree_drained_begin(BlockDriverState *bs) bdrv_do_drained_begin(bs, true, NULL, false, true); } +void bdrv_drained_begin_no_poll(BlockDriverState *bs) +{ + IO_CODE(); + bdrv_do_drained_begin(bs, false, NULL, false, false); +} + /** * This function does not poll, nor must any of its recursively called * functions. The *drained_end_counter pointee will be incremented diff --git a/include/block/block-io.h b/include/block/block-io.h index 5e3f346806..9135b648bf 100644 --- a/include/block/block-io.h +++ b/include/block/block-io.h @@ -226,6 +226,17 @@ int coroutine_fn bdrv_co_copy_range(BdrvChild *src, int64_t src_offset, int64_t bytes, BdrvRequestFlags read_flags, BdrvRequestFlags write_flags); +/** + * bdrv_drained_begin_no_poll: + * + * Quiesces a BDS like bdrv_drained_begin(), but does not wait for already + * running requests to complete. + * Same as bdrv_drained_begin(), but do not poll for the subgraph to + * actually become unquiesced. Therefore, no graph changes will occur + * with this function. + */ +void bdrv_drained_begin_no_poll(BlockDriverState *bs); + /** * bdrv_drained_end_no_poll: * @@ -332,15 +343,6 @@ bool bdrv_drain_poll(BlockDriverState *bs, bool recursive, */ void bdrv_drained_begin(BlockDriverState *bs); -/** - * bdrv_do_drained_begin_quiesce: - * - * Quiesces a BDS like bdrv_drained_begin(), but does not wait for already - * running requests to complete. - */ -void bdrv_do_drained_begin_quiesce(BlockDriverState *bs, - BdrvChild *parent, bool ignore_bds_parents); - /** * Like bdrv_drained_begin, but recursively begins a quiesced section for * exclusive access to all child nodes as well. -- 2.31.1
