aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
Diffstat
-rw-r--r--block.c25
-rw-r--r--block/io.c30
-rw-r--r--include/block/block_int-common.h8
-rw-r--r--tests/unit/test-bdrv-drain.c16
4 files changed, 39 insertions, 40 deletions
diff --git a/block.c b/block.c
index 7ea0b82049..b8bab06e55 100644
--- a/block.c
+++ b/block.c
@@ -2855,7 +2855,6 @@ static void bdrv_replace_child_noperm(BdrvChild *child,
{
BlockDriverState *old_bs = child->bs;
int new_bs_quiesce_counter;
- int drain_saldo;
assert(!child->frozen);
assert(old_bs != new_bs);
@@ -2865,16 +2864,13 @@ static void bdrv_replace_child_noperm(BdrvChild *child,
assert(bdrv_get_aio_context(old_bs) == bdrv_get_aio_context(new_bs));
}
- new_bs_quiesce_counter = (new_bs ? new_bs->quiesce_counter : 0);
- drain_saldo = new_bs_quiesce_counter - child->parent_quiesce_counter;
-
/*
* If the new child node is drained but the old one was not, flush
* all outstanding requests to the old child node.
*/
- while (drain_saldo > 0 && child->klass->drained_begin) {
+ new_bs_quiesce_counter = (new_bs ? new_bs->quiesce_counter : 0);
+ if (new_bs_quiesce_counter && !child->quiesced_parent) {
bdrv_parent_drained_begin_single(child, true);
- drain_saldo--;
}
if (old_bs) {
@@ -2890,16 +2886,6 @@ static void bdrv_replace_child_noperm(BdrvChild *child,
if (new_bs) {
assert_bdrv_graph_writable(new_bs);
QLIST_INSERT_HEAD(&new_bs->parents, child, next_parent);
-
- /*
- * Polling in bdrv_parent_drained_begin_single() may have led to the new
- * node's quiesce_counter having been decreased. Not a problem, we just
- * need to recognize this here and then invoke drained_end appropriately
- * more often.
- */
- assert(new_bs->quiesce_counter <= new_bs_quiesce_counter);
- drain_saldo += new_bs->quiesce_counter - new_bs_quiesce_counter;
-
if (child->klass->attach) {
child->klass->attach(child);
}
@@ -2908,10 +2894,13 @@ static void bdrv_replace_child_noperm(BdrvChild *child,
/*
* If the old child node was drained but the new one is not, allow
* requests to come in only after the new node has been attached.
+ *
+ * Update new_bs_quiesce_counter because bdrv_parent_drained_begin_single()
+ * polls, which could have changed the value.
*/
- while (drain_saldo < 0 && child->klass->drained_end) {
+ new_bs_quiesce_counter = (new_bs ? new_bs->quiesce_counter : 0);
+ if (!new_bs_quiesce_counter && child->quiesced_parent) {
bdrv_parent_drained_end_single(child);
- drain_saldo++;
}
}
diff --git a/block/io.c b/block/io.c
index 75224480d0..87d6f22ec4 100644
--- a/block/io.c
+++ b/block/io.c
@@ -62,8 +62,9 @@ void bdrv_parent_drained_end_single(BdrvChild *c)
{
IO_OR_GS_CODE();
- assert(c->parent_quiesce_counter > 0);
- c->parent_quiesce_counter--;
+ assert(c->quiesced_parent);
+ c->quiesced_parent = false;
+
if (c->klass->drained_end) {
c->klass->drained_end(c);
}
@@ -110,7 +111,10 @@ void bdrv_parent_drained_begin_single(BdrvChild *c, bool poll)
{
AioContext *ctx = bdrv_child_get_parent_aio_context(c);
IO_OR_GS_CODE();
- c->parent_quiesce_counter++;
+
+ assert(!c->quiesced_parent);
+ c->quiesced_parent = true;
+
if (c->klass->drained_begin) {
c->klass->drained_begin(c);
}
@@ -358,11 +362,12 @@ void bdrv_do_drained_begin_quiesce(BlockDriverState *bs,
/* Stop things in parent-to-child order */
if (qatomic_fetch_inc(&bs->quiesce_counter) == 0) {
aio_disable_external(bdrv_get_aio_context(bs));
- }
- bdrv_parent_drained_begin(bs, parent, ignore_bds_parents);
- if (bs->drv && bs->drv->bdrv_drain_begin) {
- bs->drv->bdrv_drain_begin(bs);
+ /* TODO Remove ignore_bds_parents, we don't consider it any more */
+ bdrv_parent_drained_begin(bs, parent, false);
+ if (bs->drv && bs->drv->bdrv_drain_begin) {
+ bs->drv->bdrv_drain_begin(bs);
+ }
}
}
@@ -413,13 +418,14 @@ static void bdrv_do_drained_end(BlockDriverState *bs, BdrvChild *parent,
assert(bs->quiesce_counter > 0);
/* Re-enable things in child-to-parent order */
- if (bs->drv && bs->drv->bdrv_drain_end) {
- bs->drv->bdrv_drain_end(bs);
- }
- bdrv_parent_drained_end(bs, parent, ignore_bds_parents);
-
old_quiesce_counter = qatomic_fetch_dec(&bs->quiesce_counter);
if (old_quiesce_counter == 1) {
+ if (bs->drv && bs->drv->bdrv_drain_end) {
+ bs->drv->bdrv_drain_end(bs);
+ }
+ /* TODO Remove ignore_bds_parents, we don't consider it any more */
+ bdrv_parent_drained_end(bs, parent, false);
+
aio_enable_external(bdrv_get_aio_context(bs));
}
}
diff --git a/include/block/block_int-common.h b/include/block/block_int-common.h
index 791dddfd7d..a6bc6b7fe9 100644
--- a/include/block/block_int-common.h
+++ b/include/block/block_int-common.h
@@ -980,13 +980,13 @@ struct BdrvChild {
bool frozen;
/*
- * How many times the parent of this child has been drained
+ * True if the parent of this child has been drained by this BdrvChild
* (through klass->drained_*).
- * Usually, this is equal to bs->quiesce_counter (potentially
- * reduced by bdrv_drain_all_count). It may differ while the
+ *
+ * It is generally true if bs->quiesce_counter > 0. It may differ while the
* child is entering or leaving a drained section.
*/
- int parent_quiesce_counter;
+ bool quiesced_parent;
QLIST_ENTRY(BdrvChild) next;
QLIST_ENTRY(BdrvChild) next_parent;
diff --git a/tests/unit/test-bdrv-drain.c b/tests/unit/test-bdrv-drain.c
index dda08de8db..172bc6debc 100644
--- a/tests/unit/test-bdrv-drain.c
+++ b/tests/unit/test-bdrv-drain.c
@@ -296,7 +296,11 @@ static void test_quiesce_common(enum drain_type drain_type, bool recursive)
do_drain_begin(drain_type, bs);
- g_assert_cmpint(bs->quiesce_counter, ==, 1);
+ if (drain_type == BDRV_DRAIN_ALL) {
+ g_assert_cmpint(bs->quiesce_counter, ==, 2);
+ } else {
+ g_assert_cmpint(bs->quiesce_counter, ==, 1);
+ }
g_assert_cmpint(backing->quiesce_counter, ==, !!recursive);
do_drain_end(drain_type, bs);
@@ -348,8 +352,8 @@ static void test_nested(void)
for (outer = 0; outer < DRAIN_TYPE_MAX; outer++) {
for (inner = 0; inner < DRAIN_TYPE_MAX; inner++) {
- int backing_quiesce = (outer != BDRV_DRAIN) +
- (inner != BDRV_DRAIN);
+ int backing_quiesce = (outer == BDRV_DRAIN_ALL) +
+ (inner == BDRV_DRAIN_ALL);
g_assert_cmpint(bs->quiesce_counter, ==, 0);
g_assert_cmpint(backing->quiesce_counter, ==, 0);
@@ -359,10 +363,10 @@ static void test_nested(void)
do_drain_begin(outer, bs);
do_drain_begin(inner, bs);
- g_assert_cmpint(bs->quiesce_counter, ==, 2);
+ g_assert_cmpint(bs->quiesce_counter, ==, 2 + !!backing_quiesce);
g_assert_cmpint(backing->quiesce_counter, ==, backing_quiesce);
- g_assert_cmpint(s->drain_count, ==, 2);
- g_assert_cmpint(backing_s->drain_count, ==, backing_quiesce);
+ g_assert_cmpint(s->drain_count, ==, 1);
+ g_assert_cmpint(backing_s->drain_count, ==, !!backing_quiesce);
do_drain_end(inner, bs);
do_drain_end(outer, bs);
generated by cgit v1.2.3 (git 2.26.2) at 2025-02-24 01:59:21 +0000