From 58a794ea48e1a6c6f5711f07e34024c037e4c4b1 Mon Sep 17 00:00:00 2001 From: Jeffrey Cody Date: Thu, 30 Nov 2017 22:49:05 +0100 Subject: [PATCH 01/21] block: add bdrv_co_drain_end callback RH-Author: Jeffrey Cody Message-id: <5493cbaa3bab031054077168340f5aff55b6be2e.1511985875.git.jcody@redhat.com> Patchwork-id: 78040 O-Subject: [RHV7.5 qemu-kvm-rhev PATCH 01/11] block: add bdrv_co_drain_end callback Bugzilla: 1506531 RH-Acked-by: Paolo Bonzini RH-Acked-by: Stefan Hajnoczi RH-Acked-by: John Snow From: Manos Pitsidianakis BlockDriverState has a bdrv_co_drain() callback but no equivalent for the end of the drain. The throttle driver (block/throttle.c) needs a way to mark the end of the drain in order to toggle io_limits_disabled correctly, thus bdrv_co_drain_end is needed. Signed-off-by: Manos Pitsidianakis Reviewed-by: Stefan Hajnoczi Reviewed-by: Fam Zheng Signed-off-by: Stefan Hajnoczi (cherry picked from commit 481cad48e5e655746893e001af31c161f4587a02) Signed-off-by: Jeff Cody Signed-off-by: Miroslav Rezanina --- block/io.c | 48 +++++++++++++++++++++++++++++++++-------------- include/block/block_int.h | 11 +++++++++-- 2 files changed, 43 insertions(+), 16 deletions(-) diff --git a/block/io.c b/block/io.c index 2600381..93fb802 100644 --- a/block/io.c +++ b/block/io.c @@ -153,6 +153,7 @@ typedef struct { Coroutine *co; BlockDriverState *bs; bool done; + bool begin; } BdrvCoDrainData; static void coroutine_fn bdrv_drain_invoke_entry(void *opaque) @@ -160,18 +161,23 @@ static void coroutine_fn bdrv_drain_invoke_entry(void *opaque) BdrvCoDrainData *data = opaque; BlockDriverState *bs = data->bs; - bs->drv->bdrv_co_drain(bs); + if (data->begin) { + bs->drv->bdrv_co_drain(bs); + } else { + bs->drv->bdrv_co_drain_end(bs); + } /* Set data->done before reading bs->wakeup. */ atomic_mb_set(&data->done, true); bdrv_wakeup(bs); } -static void bdrv_drain_invoke(BlockDriverState *bs) +static void bdrv_drain_invoke(BlockDriverState *bs, bool begin) { - BdrvCoDrainData data = { .bs = bs, .done = false }; + BdrvCoDrainData data = { .bs = bs, .done = false, .begin = begin}; - if (!bs->drv || !bs->drv->bdrv_co_drain) { + if (!bs->drv || (begin && !bs->drv->bdrv_co_drain) || + (!begin && !bs->drv->bdrv_co_drain_end)) { return; } @@ -180,15 +186,16 @@ static void bdrv_drain_invoke(BlockDriverState *bs) BDRV_POLL_WHILE(bs, !data.done); } -static bool bdrv_drain_recurse(BlockDriverState *bs) +static bool bdrv_drain_recurse(BlockDriverState *bs, bool begin) { BdrvChild *child, *tmp; bool waited; - waited = BDRV_POLL_WHILE(bs, atomic_read(&bs->in_flight) > 0); - /* Ensure any pending metadata writes are submitted to bs->file. */ - bdrv_drain_invoke(bs); + bdrv_drain_invoke(bs, begin); + + /* Wait for drained requests to finish */ + waited = BDRV_POLL_WHILE(bs, atomic_read(&bs->in_flight) > 0); QLIST_FOREACH_SAFE(child, &bs->children, next, tmp) { BlockDriverState *bs = child->bs; @@ -205,7 +212,7 @@ static bool bdrv_drain_recurse(BlockDriverState *bs) */ bdrv_ref(bs); } - waited |= bdrv_drain_recurse(bs); + waited |= bdrv_drain_recurse(bs, begin); if (in_main_loop) { bdrv_unref(bs); } @@ -221,12 +228,18 @@ static void bdrv_co_drain_bh_cb(void *opaque) BlockDriverState *bs = data->bs; bdrv_dec_in_flight(bs); - bdrv_drained_begin(bs); + if (data->begin) { + bdrv_drained_begin(bs); + } else { + bdrv_drained_end(bs); + } + data->done = true; aio_co_wake(co); } -static void coroutine_fn bdrv_co_yield_to_drain(BlockDriverState *bs) +static void coroutine_fn bdrv_co_yield_to_drain(BlockDriverState *bs, + bool begin) { BdrvCoDrainData data; @@ -239,6 +252,7 @@ static void coroutine_fn bdrv_co_yield_to_drain(BlockDriverState *bs) .co = qemu_coroutine_self(), .bs = bs, .done = false, + .begin = begin, }; bdrv_inc_in_flight(bs); aio_bh_schedule_oneshot(bdrv_get_aio_context(bs), @@ -253,7 +267,7 @@ static void coroutine_fn bdrv_co_yield_to_drain(BlockDriverState *bs) void bdrv_drained_begin(BlockDriverState *bs) { if (qemu_in_coroutine()) { - bdrv_co_yield_to_drain(bs); + bdrv_co_yield_to_drain(bs, true); return; } @@ -262,17 +276,22 @@ void bdrv_drained_begin(BlockDriverState *bs) bdrv_parent_drained_begin(bs); } - bdrv_drain_recurse(bs); + bdrv_drain_recurse(bs, true); } void bdrv_drained_end(BlockDriverState *bs) { + if (qemu_in_coroutine()) { + bdrv_co_yield_to_drain(bs, false); + return; + } assert(bs->quiesce_counter > 0); if (atomic_fetch_dec(&bs->quiesce_counter) > 1) { return; } bdrv_parent_drained_end(bs); + bdrv_drain_recurse(bs, false); aio_enable_external(bdrv_get_aio_context(bs)); } @@ -350,7 +369,7 @@ void bdrv_drain_all_begin(void) 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); + waited |= bdrv_drain_recurse(bs, true); } } aio_context_release(aio_context); @@ -371,6 +390,7 @@ void bdrv_drain_all_end(void) aio_context_acquire(aio_context); aio_enable_external(aio_context); bdrv_parent_drained_end(bs); + bdrv_drain_recurse(bs, false); aio_context_release(aio_context); } diff --git a/include/block/block_int.h b/include/block/block_int.h index a6faf1b..98d02ba 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -320,10 +320,17 @@ struct BlockDriver { int (*bdrv_probe_geometry)(BlockDriverState *bs, HDGeometry *geo); /** - * Drain and stop any internal sources of requests in the driver, and - * remain so until next I/O callback (e.g. bdrv_co_writev) is called. + * bdrv_co_drain is called if implemented in the beginning of a + * drain operation to drain and stop any internal sources of requests in + * the driver. + * bdrv_co_drain_end is called if implemented at the end of the drain. + * + * They should be used by the driver to e.g. manage scheduled I/O + * requests, or toggle an internal state. After the end of the drain new + * requests will continue normally. */ void coroutine_fn (*bdrv_co_drain)(BlockDriverState *bs); + void coroutine_fn (*bdrv_co_drain_end)(BlockDriverState *bs); void (*bdrv_add_child)(BlockDriverState *parent, BlockDriverState *child, Error **errp); -- 1.8.3.1