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block: Use bdrv_do_drain_begin/end in bdrv_drain_all() 

bdrv_do_drain_begin/end() implement already everything that
bdrv_drain_all_begin/end() need and currently still do manually: Disable
external events, call parent drain callbacks, call block driver
callbacks.

It also does two more things:

The first is incrementing bs->quiesce_counter. bdrv_drain_all() already
stood out in the test case by behaving different from the other drain
variants. Adding this is not only safe, but in fact a bug fix.

The second is calling bdrv_drain_recurse(). We already do that later in
the same function in a loop, so basically doing an early first iteration
doesn't hurt.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
master
Kevin Wolf 2017-12-14 10:27:23 +01:00
parent bb67568954
commit 79ab8b21dc
2 changed files with 6 additions and 18 deletions
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10
block/io.c
View File

@ -413,11 +413,8 @@ void bdrv_drain_all_begin(void)
for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
AioContext *aio_context = bdrv_get_aio_context(bs);
/* Stop things in parent-to-child order */
aio_context_acquire(aio_context);
aio_disable_external(aio_context);
bdrv_parent_drained_begin(bs, NULL);
bdrv_drain_invoke(bs, true, true);
bdrv_do_drained_begin(bs, true, NULL);
aio_context_release(aio_context);
if (!g_slist_find(aio_ctxs, aio_context)) {
@ -458,11 +455,8 @@ void bdrv_drain_all_end(void)
for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
AioContext *aio_context = bdrv_get_aio_context(bs);
/* Re-enable things in child-to-parent order */
aio_context_acquire(aio_context);
bdrv_drain_invoke(bs, false, true);
bdrv_parent_drained_end(bs, NULL);
aio_enable_external(aio_context);
bdrv_do_drained_end(bs, true, NULL);
aio_context_release(aio_context);
}
}

14
tests/test-bdrv-drain.c
View File

@ -276,8 +276,7 @@ static void test_quiesce_common(enum drain_type drain_type, bool recursive)
static void test_quiesce_drain_all(void)
{
// XXX drain_all doesn't quiesce
//test_quiesce_common(BDRV_DRAIN_ALL, true);
test_quiesce_common(BDRV_DRAIN_ALL, true);
}
static void test_quiesce_drain(void)
@ -319,12 +318,7 @@ static void test_nested(void)
for (outer = 0; outer < DRAIN_TYPE_MAX; outer++) {
for (inner = 0; inner < DRAIN_TYPE_MAX; inner++) {
/* XXX bdrv_drain_all() doesn't increase the quiesce_counter */
int bs_quiesce = (outer != BDRV_DRAIN_ALL) +
(inner != BDRV_DRAIN_ALL);
int backing_quiesce = (outer == BDRV_SUBTREE_DRAIN) +
(inner == BDRV_SUBTREE_DRAIN);
int backing_cb_cnt = (outer != BDRV_DRAIN) +
int backing_quiesce = (outer != BDRV_DRAIN) +
(inner != BDRV_DRAIN);
g_assert_cmpint(bs->quiesce_counter, ==, 0);
@ -335,10 +329,10 @@ static void test_nested(void)
do_drain_begin(outer, bs);
do_drain_begin(inner, bs);
g_assert_cmpint(bs->quiesce_counter, ==, bs_quiesce);
g_assert_cmpint(bs->quiesce_counter, ==, 2);
g_assert_cmpint(backing->quiesce_counter, ==, backing_quiesce);
g_assert_cmpint(s->drain_count, ==, 2);
g_assert_cmpint(backing_s->drain_count, ==, backing_cb_cnt);
g_assert_cmpint(backing_s->drain_count, ==, backing_quiesce);
do_drain_end(inner, bs);
do_drain_end(outer, bs);