block: add bdrv_co_drain_end callback

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 <el13635@mail.ntua.gr>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
Manos Pitsidianakis 2017-09-23 14:14:09 +03:00 committed by Stefan Hajnoczi
parent f90ea7ba7c
commit 481cad48e5
2 changed files with 43 additions and 16 deletions

View File

@ -156,6 +156,7 @@ typedef struct {
Coroutine *co; Coroutine *co;
BlockDriverState *bs; BlockDriverState *bs;
bool done; bool done;
bool begin;
} BdrvCoDrainData; } BdrvCoDrainData;
static void coroutine_fn bdrv_drain_invoke_entry(void *opaque) static void coroutine_fn bdrv_drain_invoke_entry(void *opaque)
@ -163,18 +164,23 @@ static void coroutine_fn bdrv_drain_invoke_entry(void *opaque)
BdrvCoDrainData *data = opaque; BdrvCoDrainData *data = opaque;
BlockDriverState *bs = data->bs; 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. */ /* Set data->done before reading bs->wakeup. */
atomic_mb_set(&data->done, true); atomic_mb_set(&data->done, true);
bdrv_wakeup(bs); 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; return;
} }
@ -183,15 +189,16 @@ static void bdrv_drain_invoke(BlockDriverState *bs)
BDRV_POLL_WHILE(bs, !data.done); 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; BdrvChild *child, *tmp;
bool waited; bool waited;
waited = BDRV_POLL_WHILE(bs, atomic_read(&bs->in_flight) > 0);
/* Ensure any pending metadata writes are submitted to bs->file. */ /* 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) { QLIST_FOREACH_SAFE(child, &bs->children, next, tmp) {
BlockDriverState *bs = child->bs; BlockDriverState *bs = child->bs;
@ -208,7 +215,7 @@ static bool bdrv_drain_recurse(BlockDriverState *bs)
*/ */
bdrv_ref(bs); bdrv_ref(bs);
} }
waited |= bdrv_drain_recurse(bs); waited |= bdrv_drain_recurse(bs, begin);
if (in_main_loop) { if (in_main_loop) {
bdrv_unref(bs); bdrv_unref(bs);
} }
@ -224,12 +231,18 @@ static void bdrv_co_drain_bh_cb(void *opaque)
BlockDriverState *bs = data->bs; BlockDriverState *bs = data->bs;
bdrv_dec_in_flight(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; data->done = true;
aio_co_wake(co); 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; BdrvCoDrainData data;
@ -242,6 +255,7 @@ static void coroutine_fn bdrv_co_yield_to_drain(BlockDriverState *bs)
.co = qemu_coroutine_self(), .co = qemu_coroutine_self(),
.bs = bs, .bs = bs,
.done = false, .done = false,
.begin = begin,
}; };
bdrv_inc_in_flight(bs); bdrv_inc_in_flight(bs);
aio_bh_schedule_oneshot(bdrv_get_aio_context(bs), aio_bh_schedule_oneshot(bdrv_get_aio_context(bs),
@ -256,7 +270,7 @@ static void coroutine_fn bdrv_co_yield_to_drain(BlockDriverState *bs)
void bdrv_drained_begin(BlockDriverState *bs) void bdrv_drained_begin(BlockDriverState *bs)
{ {
if (qemu_in_coroutine()) { if (qemu_in_coroutine()) {
bdrv_co_yield_to_drain(bs); bdrv_co_yield_to_drain(bs, true);
return; return;
} }
@ -265,17 +279,22 @@ void bdrv_drained_begin(BlockDriverState *bs)
bdrv_parent_drained_begin(bs); bdrv_parent_drained_begin(bs);
} }
bdrv_drain_recurse(bs); bdrv_drain_recurse(bs, true);
} }
void bdrv_drained_end(BlockDriverState *bs) void bdrv_drained_end(BlockDriverState *bs)
{ {
if (qemu_in_coroutine()) {
bdrv_co_yield_to_drain(bs, false);
return;
}
assert(bs->quiesce_counter > 0); assert(bs->quiesce_counter > 0);
if (atomic_fetch_dec(&bs->quiesce_counter) > 1) { if (atomic_fetch_dec(&bs->quiesce_counter) > 1) {
return; return;
} }
bdrv_parent_drained_end(bs); bdrv_parent_drained_end(bs);
bdrv_drain_recurse(bs, false);
aio_enable_external(bdrv_get_aio_context(bs)); aio_enable_external(bdrv_get_aio_context(bs));
} }
@ -353,7 +372,7 @@ void bdrv_drain_all_begin(void)
aio_context_acquire(aio_context); aio_context_acquire(aio_context);
for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) { for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
if (aio_context == bdrv_get_aio_context(bs)) { if (aio_context == bdrv_get_aio_context(bs)) {
waited |= bdrv_drain_recurse(bs); waited |= bdrv_drain_recurse(bs, true);
} }
} }
aio_context_release(aio_context); aio_context_release(aio_context);
@ -374,6 +393,7 @@ void bdrv_drain_all_end(void)
aio_context_acquire(aio_context); aio_context_acquire(aio_context);
aio_enable_external(aio_context); aio_enable_external(aio_context);
bdrv_parent_drained_end(bs); bdrv_parent_drained_end(bs);
bdrv_drain_recurse(bs, false);
aio_context_release(aio_context); aio_context_release(aio_context);
} }

View File

@ -354,10 +354,17 @@ struct BlockDriver {
int (*bdrv_probe_geometry)(BlockDriverState *bs, HDGeometry *geo); int (*bdrv_probe_geometry)(BlockDriverState *bs, HDGeometry *geo);
/** /**
* Drain and stop any internal sources of requests in the driver, and * bdrv_co_drain is called if implemented in the beginning of a
* remain so until next I/O callback (e.g. bdrv_co_writev) is called. * 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)(BlockDriverState *bs);
void coroutine_fn (*bdrv_co_drain_end)(BlockDriverState *bs);
void (*bdrv_add_child)(BlockDriverState *parent, BlockDriverState *child, void (*bdrv_add_child)(BlockDriverState *parent, BlockDriverState *child,
Error **errp); Error **errp);