From 58a794ea48e1a6c6f5711f07e34024c037e4c4b1 Mon Sep 17 00:00:00 2001
From: Jeffrey Cody <jcody@redhat.com>
Date: Thu, 30 Nov 2017 22:49:05 +0100
Subject: [PATCH 01/21] block: add bdrv_co_drain_end callback
RH-Author: Jeffrey Cody <jcody@redhat.com>
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 <pbonzini@redhat.com>
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
RH-Acked-by: John Snow <jsnow@redhat.com>
From: Manos Pitsidianakis <el13635@mail.ntua.gr>
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>
(cherry picked from commit 481cad48e5e655746893e001af31c161f4587a02)
Signed-off-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
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