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qemu-kvm/SOURCES/kvm-block-ignore_bds_parents-parameter-for-drain-functio.patch

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From b4a41557a3fd97307e750c84916f9d2237f08242 Mon Sep 17 00:00:00 2001
From: Kevin Wolf <kwolf@redhat.com>
Date: Wed, 10 Oct 2018 20:21:47 +0100
Subject: [PATCH 21/49] block: ignore_bds_parents parameter for drain functions
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
RH-Author: Kevin Wolf <kwolf@redhat.com>
Message-id: <20181010202213.7372-9-kwolf@redhat.com>
Patchwork-id: 82598
O-Subject: [RHEL-8 qemu-kvm PATCH 18/44] block: ignore_bds_parents parameter for drain functions
Bugzilla: 1637976
RH-Acked-by: Max Reitz <mreitz@redhat.com>
RH-Acked-by: John Snow <jsnow@redhat.com>
RH-Acked-by: Thomas Huth <thuth@redhat.com>
In the future, bdrv_drained_all_begin/end() will drain all invidiual
nodes separately rather than whole subtrees. This means that we don't
want to propagate the drain to all parents any more: If the parent is a
BDS, it will already be drained separately. Recursing to all parents is
unnecessary work and would make it an O(n²) operation.
Prepare the drain function for the changed drain_all by adding an
ignore_bds_parents parameter to the internal implementation that
prevents the propagation of the drain to BDS parents. We still (have to)
propagate it to non-BDS parents like BlockBackends or Jobs because those
are not drained separately.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
(cherry picked from commit 6cd5c9d7b2df93ef54144f170d4c908934a4767f)
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>
---
block.c | 11 +++---
block/io.c | 88 ++++++++++++++++++++++++++++-------------------
block/vvfat.c | 1 +
include/block/block.h | 16 ++++++---
include/block/block_int.h | 6 ++++
5 files changed, 78 insertions(+), 44 deletions(-)
diff --git a/block.c b/block.c
index 5a50de6..519be6e 100644
--- a/block.c
+++ b/block.c
@@ -818,13 +818,13 @@ static char *bdrv_child_get_parent_desc(BdrvChild *c)
static void bdrv_child_cb_drained_begin(BdrvChild *child)
{
BlockDriverState *bs = child->opaque;
- bdrv_do_drained_begin_quiesce(bs, NULL);
+ bdrv_do_drained_begin_quiesce(bs, NULL, false);
}
static bool bdrv_child_cb_drained_poll(BdrvChild *child)
{
BlockDriverState *bs = child->opaque;
- return bdrv_drain_poll(bs, false, NULL);
+ return bdrv_drain_poll(bs, false, NULL, false);
}
static void bdrv_child_cb_drained_end(BdrvChild *child)
@@ -908,6 +908,7 @@ static void bdrv_inherited_options(int *child_flags, QDict *child_options,
}
const BdrvChildRole child_file = {
+ .parent_is_bds = true,
.get_parent_desc = bdrv_child_get_parent_desc,
.inherit_options = bdrv_inherited_options,
.drained_begin = bdrv_child_cb_drained_begin,
@@ -933,6 +934,7 @@ static void bdrv_inherited_fmt_options(int *child_flags, QDict *child_options,
}
const BdrvChildRole child_format = {
+ .parent_is_bds = true,
.get_parent_desc = bdrv_child_get_parent_desc,
.inherit_options = bdrv_inherited_fmt_options,
.drained_begin = bdrv_child_cb_drained_begin,
@@ -1051,6 +1053,7 @@ static int bdrv_backing_update_filename(BdrvChild *c, BlockDriverState *base,
}
const BdrvChildRole child_backing = {
+ .parent_is_bds = true,
.get_parent_desc = bdrv_child_get_parent_desc,
.attach = bdrv_backing_attach,
.detach = bdrv_backing_detach,
@@ -4901,7 +4904,7 @@ void bdrv_set_aio_context(BlockDriverState *bs, AioContext *new_context)
AioContext *ctx = bdrv_get_aio_context(bs);
aio_disable_external(ctx);
- bdrv_parent_drained_begin(bs, NULL);
+ bdrv_parent_drained_begin(bs, NULL, false);
bdrv_drain(bs); /* ensure there are no in-flight requests */
while (aio_poll(ctx, false)) {
@@ -4915,7 +4918,7 @@ void bdrv_set_aio_context(BlockDriverState *bs, AioContext *new_context)
*/
aio_context_acquire(new_context);
bdrv_attach_aio_context(bs, new_context);
- bdrv_parent_drained_end(bs, NULL);
+ bdrv_parent_drained_end(bs, NULL, false);
aio_enable_external(ctx);
aio_context_release(new_context);
}
diff --git a/block/io.c b/block/io.c
index b58c91b..0021fefd 100644
--- a/block/io.c
+++ b/block/io.c
@@ -41,12 +41,13 @@
static int coroutine_fn bdrv_co_do_pwrite_zeroes(BlockDriverState *bs,
int64_t offset, int bytes, BdrvRequestFlags flags);
-void bdrv_parent_drained_begin(BlockDriverState *bs, BdrvChild *ignore)
+void bdrv_parent_drained_begin(BlockDriverState *bs, BdrvChild *ignore,
+ bool ignore_bds_parents)
{
BdrvChild *c, *next;
QLIST_FOREACH_SAFE(c, &bs->parents, next_parent, next) {
- if (c == ignore) {
+ if (c == ignore || (ignore_bds_parents && c->role->parent_is_bds)) {
continue;
}
if (c->role->drained_begin) {
@@ -55,12 +56,13 @@ void bdrv_parent_drained_begin(BlockDriverState *bs, BdrvChild *ignore)
}
}
-void bdrv_parent_drained_end(BlockDriverState *bs, BdrvChild *ignore)
+void bdrv_parent_drained_end(BlockDriverState *bs, BdrvChild *ignore,
+ bool ignore_bds_parents)
{
BdrvChild *c, *next;
QLIST_FOREACH_SAFE(c, &bs->parents, next_parent, next) {
- if (c == ignore) {
+ if (c == ignore || (ignore_bds_parents && c->role->parent_is_bds)) {
continue;
}
if (c->role->drained_end) {
@@ -69,13 +71,14 @@ void bdrv_parent_drained_end(BlockDriverState *bs, BdrvChild *ignore)
}
}
-static bool bdrv_parent_drained_poll(BlockDriverState *bs, BdrvChild *ignore)
+static bool bdrv_parent_drained_poll(BlockDriverState *bs, BdrvChild *ignore,
+ bool ignore_bds_parents)
{
BdrvChild *c, *next;
bool busy = false;
QLIST_FOREACH_SAFE(c, &bs->parents, next_parent, next) {
- if (c == ignore) {
+ if (c == ignore || (ignore_bds_parents && c->role->parent_is_bds)) {
continue;
}
if (c->role->drained_poll) {
@@ -166,6 +169,7 @@ typedef struct {
bool recursive;
bool poll;
BdrvChild *parent;
+ bool ignore_bds_parents;
} BdrvCoDrainData;
static void coroutine_fn bdrv_drain_invoke_entry(void *opaque)
@@ -219,11 +223,11 @@ static void bdrv_drain_invoke(BlockDriverState *bs, bool begin)
/* Returns true if BDRV_POLL_WHILE() should go into a blocking aio_poll() */
bool bdrv_drain_poll(BlockDriverState *bs, bool recursive,
- BdrvChild *ignore_parent)
+ BdrvChild *ignore_parent, bool ignore_bds_parents)
{
BdrvChild *child, *next;
- if (bdrv_parent_drained_poll(bs, ignore_parent)) {
+ if (bdrv_parent_drained_poll(bs, ignore_parent, ignore_bds_parents)) {
return true;
}
@@ -232,8 +236,9 @@ bool bdrv_drain_poll(BlockDriverState *bs, bool recursive,
}
if (recursive) {
+ assert(!ignore_bds_parents);
QLIST_FOREACH_SAFE(child, &bs->children, next, next) {
- if (bdrv_drain_poll(child->bs, recursive, child)) {
+ if (bdrv_drain_poll(child->bs, recursive, child, false)) {
return true;
}
}
@@ -249,13 +254,14 @@ static bool bdrv_drain_poll_top_level(BlockDriverState *bs, bool recursive,
* have executed. */
while (aio_poll(bs->aio_context, false));
- return bdrv_drain_poll(bs, recursive, ignore_parent);
+ return bdrv_drain_poll(bs, recursive, ignore_parent, false);
}
static void bdrv_do_drained_begin(BlockDriverState *bs, bool recursive,
- BdrvChild *parent, bool poll);
+ BdrvChild *parent, bool ignore_bds_parents,
+ bool poll);
static void bdrv_do_drained_end(BlockDriverState *bs, bool recursive,
- BdrvChild *parent);
+ BdrvChild *parent, bool ignore_bds_parents);
static void bdrv_co_drain_bh_cb(void *opaque)
{
@@ -266,9 +272,11 @@ static void bdrv_co_drain_bh_cb(void *opaque)
if (bs) {
bdrv_dec_in_flight(bs);
if (data->begin) {
- bdrv_do_drained_begin(bs, data->recursive, data->parent, data->poll);
+ bdrv_do_drained_begin(bs, data->recursive, data->parent,
+ data->ignore_bds_parents, data->poll);
} else {
- bdrv_do_drained_end(bs, data->recursive, data->parent);
+ bdrv_do_drained_end(bs, data->recursive, data->parent,
+ data->ignore_bds_parents);
}
} else {
assert(data->begin);
@@ -281,7 +289,9 @@ static void bdrv_co_drain_bh_cb(void *opaque)
static void coroutine_fn bdrv_co_yield_to_drain(BlockDriverState *bs,
bool begin, bool recursive,
- BdrvChild *parent, bool poll)
+ BdrvChild *parent,
+ bool ignore_bds_parents,
+ bool poll)
{
BdrvCoDrainData data;
@@ -296,6 +306,7 @@ static void coroutine_fn bdrv_co_yield_to_drain(BlockDriverState *bs,
.begin = begin,
.recursive = recursive,
.parent = parent,
+ .ignore_bds_parents = ignore_bds_parents,
.poll = poll,
};
if (bs) {
@@ -311,7 +322,7 @@ static void coroutine_fn bdrv_co_yield_to_drain(BlockDriverState *bs,
}
void bdrv_do_drained_begin_quiesce(BlockDriverState *bs,
- BdrvChild *parent)
+ BdrvChild *parent, bool ignore_bds_parents)
{
assert(!qemu_in_coroutine());
@@ -320,26 +331,30 @@ void bdrv_do_drained_begin_quiesce(BlockDriverState *bs,
aio_disable_external(bdrv_get_aio_context(bs));
}
- bdrv_parent_drained_begin(bs, parent);
+ bdrv_parent_drained_begin(bs, parent, ignore_bds_parents);
bdrv_drain_invoke(bs, true);
}
static void bdrv_do_drained_begin(BlockDriverState *bs, bool recursive,
- BdrvChild *parent, bool poll)
+ BdrvChild *parent, bool ignore_bds_parents,
+ bool poll)
{
BdrvChild *child, *next;
if (qemu_in_coroutine()) {
- bdrv_co_yield_to_drain(bs, true, recursive, parent, poll);
+ bdrv_co_yield_to_drain(bs, true, recursive, parent, ignore_bds_parents,
+ poll);
return;
}
- bdrv_do_drained_begin_quiesce(bs, parent);
+ bdrv_do_drained_begin_quiesce(bs, parent, ignore_bds_parents);
if (recursive) {
+ assert(!ignore_bds_parents);
bs->recursive_quiesce_counter++;
QLIST_FOREACH_SAFE(child, &bs->children, next, next) {
- bdrv_do_drained_begin(child->bs, true, child, false);
+ bdrv_do_drained_begin(child->bs, true, child, ignore_bds_parents,
+ false);
}
}
@@ -353,28 +368,30 @@ static void bdrv_do_drained_begin(BlockDriverState *bs, bool recursive,
* nodes.
*/
if (poll) {
+ assert(!ignore_bds_parents);
BDRV_POLL_WHILE(bs, bdrv_drain_poll_top_level(bs, recursive, parent));
}
}
void bdrv_drained_begin(BlockDriverState *bs)
{
- bdrv_do_drained_begin(bs, false, NULL, true);
+ bdrv_do_drained_begin(bs, false, NULL, false, true);
}
void bdrv_subtree_drained_begin(BlockDriverState *bs)
{
- bdrv_do_drained_begin(bs, true, NULL, true);
+ bdrv_do_drained_begin(bs, true, NULL, false, true);
}
-void bdrv_do_drained_end(BlockDriverState *bs, bool recursive,
- BdrvChild *parent)
+static void bdrv_do_drained_end(BlockDriverState *bs, bool recursive,
+ BdrvChild *parent, bool ignore_bds_parents)
{
BdrvChild *child, *next;
int old_quiesce_counter;
if (qemu_in_coroutine()) {
- bdrv_co_yield_to_drain(bs, false, recursive, parent, false);
+ bdrv_co_yield_to_drain(bs, false, recursive, parent, ignore_bds_parents,
+ false);
return;
}
assert(bs->quiesce_counter > 0);
@@ -382,27 +399,28 @@ void bdrv_do_drained_end(BlockDriverState *bs, bool recursive,
/* Re-enable things in child-to-parent order */
bdrv_drain_invoke(bs, false);
- bdrv_parent_drained_end(bs, parent);
+ bdrv_parent_drained_end(bs, parent, ignore_bds_parents);
if (old_quiesce_counter == 1) {
aio_enable_external(bdrv_get_aio_context(bs));
}
if (recursive) {
+ assert(!ignore_bds_parents);
bs->recursive_quiesce_counter--;
QLIST_FOREACH_SAFE(child, &bs->children, next, next) {
- bdrv_do_drained_end(child->bs, true, child);
+ bdrv_do_drained_end(child->bs, true, child, ignore_bds_parents);
}
}
}
void bdrv_drained_end(BlockDriverState *bs)
{
- bdrv_do_drained_end(bs, false, NULL);
+ bdrv_do_drained_end(bs, false, NULL, false);
}
void bdrv_subtree_drained_end(BlockDriverState *bs)
{
- bdrv_do_drained_end(bs, true, NULL);
+ bdrv_do_drained_end(bs, true, NULL, false);
}
void bdrv_apply_subtree_drain(BdrvChild *child, BlockDriverState *new_parent)
@@ -410,7 +428,7 @@ void bdrv_apply_subtree_drain(BdrvChild *child, BlockDriverState *new_parent)
int i;
for (i = 0; i < new_parent->recursive_quiesce_counter; i++) {
- bdrv_do_drained_begin(child->bs, true, child, true);
+ bdrv_do_drained_begin(child->bs, true, child, false, true);
}
}
@@ -419,7 +437,7 @@ void bdrv_unapply_subtree_drain(BdrvChild *child, BlockDriverState *old_parent)
int i;
for (i = 0; i < old_parent->recursive_quiesce_counter; i++) {
- bdrv_do_drained_end(child->bs, true, child);
+ bdrv_do_drained_end(child->bs, true, child, false);
}
}
@@ -471,7 +489,7 @@ void bdrv_drain_all_begin(void)
BdrvNextIterator it;
if (qemu_in_coroutine()) {
- bdrv_co_yield_to_drain(NULL, true, false, NULL, true);
+ bdrv_co_yield_to_drain(NULL, true, false, NULL, false, true);
return;
}
@@ -485,7 +503,7 @@ void bdrv_drain_all_begin(void)
AioContext *aio_context = bdrv_get_aio_context(bs);
aio_context_acquire(aio_context);
- bdrv_do_drained_begin(bs, true, NULL, true);
+ bdrv_do_drained_begin(bs, true, NULL, false, true);
aio_context_release(aio_context);
}
@@ -503,7 +521,7 @@ void bdrv_drain_all_end(void)
AioContext *aio_context = bdrv_get_aio_context(bs);
aio_context_acquire(aio_context);
- bdrv_do_drained_end(bs, true, NULL);
+ bdrv_do_drained_end(bs, true, NULL, false);
aio_context_release(aio_context);
}
}
diff --git a/block/vvfat.c b/block/vvfat.c
index 4595f33..c7d2ed2 100644
--- a/block/vvfat.c
+++ b/block/vvfat.c
@@ -3134,6 +3134,7 @@ static void vvfat_qcow_options(int *child_flags, QDict *child_options,
}
static const BdrvChildRole child_vvfat_qcow = {
+ .parent_is_bds = true,
.inherit_options = vvfat_qcow_options,
};
diff --git a/include/block/block.h b/include/block/block.h
index 43f29b5..6e91803 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -585,7 +585,8 @@ void bdrv_io_unplug(BlockDriverState *bs);
* Begin a quiesced section of all users of @bs. This is part of
* bdrv_drained_begin.
*/
-void bdrv_parent_drained_begin(BlockDriverState *bs, BdrvChild *ignore);
+void bdrv_parent_drained_begin(BlockDriverState *bs, BdrvChild *ignore,
+ bool ignore_bds_parents);
/**
* bdrv_parent_drained_end:
@@ -593,18 +594,23 @@ void bdrv_parent_drained_begin(BlockDriverState *bs, BdrvChild *ignore);
* End a quiesced section of all users of @bs. This is part of
* bdrv_drained_end.
*/
-void bdrv_parent_drained_end(BlockDriverState *bs, BdrvChild *ignore);
+void bdrv_parent_drained_end(BlockDriverState *bs, BdrvChild *ignore,
+ bool ignore_bds_parents);
/**
* bdrv_drain_poll:
*
* Poll for pending requests in @bs, its parents (except for @ignore_parent),
- * and if @recursive is true its children as well.
+ * and if @recursive is true its children as well (used for subtree drain).
+ *
+ * If @ignore_bds_parents is true, parents that are BlockDriverStates must
+ * ignore the drain request because they will be drained separately (used for
+ * drain_all).
*
* This is part of bdrv_drained_begin.
*/
bool bdrv_drain_poll(BlockDriverState *bs, bool recursive,
- BdrvChild *ignore_parent);
+ BdrvChild *ignore_parent, bool ignore_bds_parents);
/**
* bdrv_drained_begin:
@@ -625,7 +631,7 @@ void bdrv_drained_begin(BlockDriverState *bs);
* running requests to complete.
*/
void bdrv_do_drained_begin_quiesce(BlockDriverState *bs,
- BdrvChild *parent);
+ BdrvChild *parent, bool ignore_bds_parents);
/**
* Like bdrv_drained_begin, but recursively begins a quiesced section for
diff --git a/include/block/block_int.h b/include/block/block_int.h
index beeacde..0ad8a76 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -582,6 +582,12 @@ struct BdrvChildRole {
* points to. */
bool stay_at_node;
+ /* If true, the parent is a BlockDriverState and bdrv_next_all_states()
+ * will return it. This information is used for drain_all, where every node
+ * will be drained separately, so the drain only needs to be propagated to
+ * non-BDS parents. */
+ bool parent_is_bds;
+
void (*inherit_options)(int *child_flags, QDict *child_options,
int parent_flags, QDict *parent_options);
--
1.8.3.1
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