From 0dc7990533cef41e58579ee96315aca1fdc44ea1 Mon Sep 17 00:00:00 2001

From: Kevin Wolf <kwolf@redhat.com>

Date: Fri, 18 Nov 2022 18:41:07 +0100

Subject: [PATCH 25/31] block: Remove ignore_bds_parents parameter from

 drain_begin/end.

RH-Author: Stefano Garzarella <sgarzare@redhat.com>

RH-MergeRequest: 135: block: Simplify drain to prevent QEMU from crashing during snapshot

RH-Bugzilla: 2155112

RH-Acked-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>

RH-Acked-by: Hanna Czenczek <hreitz@redhat.com>

RH-Acked-by: Kevin Wolf <kwolf@redhat.com>

RH-Commit: [13/16] 1ed88d975a9569bffeb33ad847874417780ce408 (sgarzarella/qemu-kvm-c-9-s)

ignore_bds_parents is now ignored during drain_begin and drain_end, so

we can just remove it there. It is still a valid optimisation for

drain_all in bdrv_drained_poll(), so leave it around there.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>

Message-Id: <20221118174110.55183-13-kwolf@redhat.com>

Reviewed-by: Hanna Reitz <hreitz@redhat.com>

Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>

Signed-off-by: Kevin Wolf <kwolf@redhat.com>

(cherry picked from commit a82a3bd135078d14f1bb4b5e50f51e77d3748270)

Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>

---

 block.c                  |  2 +-

 block/io.c               | 58 +++++++++++++++-------------------------

 include/block/block-io.h |  3 +--

 3 files changed, 24 insertions(+), 39 deletions(-)

diff --git a/block.c b/block.c

index 5a583e260d..af31a94863 100644

--- a/block.c

+++ b/block.c

@@ -1226,7 +1226,7 @@ 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, false);

+    bdrv_do_drained_begin_quiesce(bs, NULL);

 }

 static bool bdrv_child_cb_drained_poll(BdrvChild *child)

diff --git a/block/io.c b/block/io.c

index 87d6f22ec4..2e9503df6a 100644

--- a/block/io.c

+++ b/block/io.c

@@ -45,13 +45,12 @@ static void bdrv_parent_cb_resize(BlockDriverState *bs);

 static int coroutine_fn bdrv_co_do_pwrite_zeroes(BlockDriverState *bs,

     int64_t offset, int64_t bytes, BdrvRequestFlags flags);

-static void bdrv_parent_drained_begin(BlockDriverState *bs, BdrvChild *ignore,

-                                      bool ignore_bds_parents)

+static void bdrv_parent_drained_begin(BlockDriverState *bs, BdrvChild *ignore)

 {

     BdrvChild *c, *next;

     QLIST_FOREACH_SAFE(c, &bs->parents, next_parent, next) {

-        if (c == ignore || (ignore_bds_parents && c->klass->parent_is_bds)) {

+        if (c == ignore) {

             continue;

         }

         bdrv_parent_drained_begin_single(c, false);

@@ -70,13 +69,12 @@ void bdrv_parent_drained_end_single(BdrvChild *c)

     }

 }

-static void bdrv_parent_drained_end(BlockDriverState *bs, BdrvChild *ignore,

-                                    bool ignore_bds_parents)

+static void bdrv_parent_drained_end(BlockDriverState *bs, BdrvChild *ignore)

 {

     BdrvChild *c;

     QLIST_FOREACH(c, &bs->parents, next_parent) {

-        if (c == ignore || (ignore_bds_parents && c->klass->parent_is_bds)) {

+        if (c == ignore) {

             continue;

         }

         bdrv_parent_drained_end_single(c);

@@ -242,7 +240,6 @@ typedef struct {

     bool begin;

     bool poll;

     BdrvChild *parent;

-    bool ignore_bds_parents;

 } BdrvCoDrainData;

 /* Returns true if BDRV_POLL_WHILE() should go into a blocking aio_poll() */

@@ -269,9 +266,8 @@ static bool bdrv_drain_poll_top_level(BlockDriverState *bs,

 }

 static void bdrv_do_drained_begin(BlockDriverState *bs, BdrvChild *parent,

-                                  bool ignore_bds_parents, bool poll);

-static void bdrv_do_drained_end(BlockDriverState *bs, BdrvChild *parent,

-                                bool ignore_bds_parents);

+                                  bool poll);

+static void bdrv_do_drained_end(BlockDriverState *bs, BdrvChild *parent);

 static void bdrv_co_drain_bh_cb(void *opaque)

 {

@@ -284,11 +280,10 @@ static void bdrv_co_drain_bh_cb(void *opaque)

         aio_context_acquire(ctx);

         bdrv_dec_in_flight(bs);

         if (data->begin) {

-            bdrv_do_drained_begin(bs, data->parent, data->ignore_bds_parents,

-                                  data->poll);

+            bdrv_do_drained_begin(bs, data->parent, data->poll);

         } else {

             assert(!data->poll);

-            bdrv_do_drained_end(bs, data->parent, data->ignore_bds_parents);

+            bdrv_do_drained_end(bs, data->parent);

         }

         aio_context_release(ctx);

     } else {

@@ -303,7 +298,6 @@ static void bdrv_co_drain_bh_cb(void *opaque)

 static void coroutine_fn bdrv_co_yield_to_drain(BlockDriverState *bs,

                                                 bool begin,

                                                 BdrvChild *parent,

-                                                bool ignore_bds_parents,

                                                 bool poll)

 {

     BdrvCoDrainData data;

@@ -321,7 +315,6 @@ static void coroutine_fn bdrv_co_yield_to_drain(BlockDriverState *bs,

         .done = false,

         .begin = begin,

         .parent = parent,

-        .ignore_bds_parents = ignore_bds_parents,

         .poll = poll,

     };

@@ -353,8 +346,7 @@ static void coroutine_fn bdrv_co_yield_to_drain(BlockDriverState *bs,

     }

 }

-void bdrv_do_drained_begin_quiesce(BlockDriverState *bs,

-                                   BdrvChild *parent, bool ignore_bds_parents)

+void bdrv_do_drained_begin_quiesce(BlockDriverState *bs, BdrvChild *parent)

 {

     IO_OR_GS_CODE();

     assert(!qemu_in_coroutine());

@@ -362,9 +354,7 @@ 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));

-

-        /* TODO Remove ignore_bds_parents, we don't consider it any more */

-        bdrv_parent_drained_begin(bs, parent, false);

+        bdrv_parent_drained_begin(bs, parent);

         if (bs->drv && bs->drv->bdrv_drain_begin) {

             bs->drv->bdrv_drain_begin(bs);

         }

@@ -372,14 +362,14 @@ void bdrv_do_drained_begin_quiesce(BlockDriverState *bs,

 }

 static void bdrv_do_drained_begin(BlockDriverState *bs, BdrvChild *parent,

-                                  bool ignore_bds_parents, bool poll)

+                                  bool poll)

 {

     if (qemu_in_coroutine()) {

-        bdrv_co_yield_to_drain(bs, true, parent, ignore_bds_parents, poll);

+        bdrv_co_yield_to_drain(bs, true, parent, poll);

         return;

     }

-    bdrv_do_drained_begin_quiesce(bs, parent, ignore_bds_parents);

+    bdrv_do_drained_begin_quiesce(bs, parent);

     /*

      * Wait for drained requests to finish.

@@ -391,7 +381,6 @@ static void bdrv_do_drained_begin(BlockDriverState *bs, BdrvChild *parent,

      * nodes.

      */

     if (poll) {

-        assert(!ignore_bds_parents);

         BDRV_POLL_WHILE(bs, bdrv_drain_poll_top_level(bs, parent));

     }

 }

@@ -399,20 +388,19 @@ static void bdrv_do_drained_begin(BlockDriverState *bs, BdrvChild *parent,

 void bdrv_drained_begin(BlockDriverState *bs)

 {

     IO_OR_GS_CODE();

-    bdrv_do_drained_begin(bs, NULL, false, true);

+    bdrv_do_drained_begin(bs, NULL, true);

 }

 /**

  * This function does not poll, nor must any of its recursively called

  * functions.

  */

-static void bdrv_do_drained_end(BlockDriverState *bs, BdrvChild *parent,

-                                bool ignore_bds_parents)

+static void bdrv_do_drained_end(BlockDriverState *bs, BdrvChild *parent)

 {

     int old_quiesce_counter;

     if (qemu_in_coroutine()) {

-        bdrv_co_yield_to_drain(bs, false, parent, ignore_bds_parents, false);

+        bdrv_co_yield_to_drain(bs, false, parent, false);

         return;

     }

     assert(bs->quiesce_counter > 0);

@@ -423,9 +411,7 @@ static void bdrv_do_drained_end(BlockDriverState *bs, BdrvChild *parent,

         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);

-

+        bdrv_parent_drained_end(bs, parent);

         aio_enable_external(bdrv_get_aio_context(bs));

     }

 }

@@ -433,7 +419,7 @@ static void bdrv_do_drained_end(BlockDriverState *bs, BdrvChild *parent,

 void bdrv_drained_end(BlockDriverState *bs)

 {

     IO_OR_GS_CODE();

-    bdrv_do_drained_end(bs, NULL, false);

+    bdrv_do_drained_end(bs, NULL);

 }

 void bdrv_drain(BlockDriverState *bs)

@@ -491,7 +477,7 @@ void bdrv_drain_all_begin(void)

     GLOBAL_STATE_CODE();

     if (qemu_in_coroutine()) {

-        bdrv_co_yield_to_drain(NULL, true, NULL, true, true);

+        bdrv_co_yield_to_drain(NULL, true, NULL, true);

         return;

     }

@@ -516,7 +502,7 @@ void bdrv_drain_all_begin(void)

         AioContext *aio_context = bdrv_get_aio_context(bs);

         aio_context_acquire(aio_context);

-        bdrv_do_drained_begin(bs, NULL, true, false);

+        bdrv_do_drained_begin(bs, NULL, false);

         aio_context_release(aio_context);

     }

@@ -536,7 +522,7 @@ void bdrv_drain_all_end_quiesce(BlockDriverState *bs)

     g_assert(!bs->refcnt);

     while (bs->quiesce_counter) {

-        bdrv_do_drained_end(bs, NULL, true);

+        bdrv_do_drained_end(bs, NULL);

     }

 }

@@ -558,7 +544,7 @@ void bdrv_drain_all_end(void)

         AioContext *aio_context = bdrv_get_aio_context(bs);

         aio_context_acquire(aio_context);

-        bdrv_do_drained_end(bs, NULL, true);

+        bdrv_do_drained_end(bs, NULL);

         aio_context_release(aio_context);

     }

diff --git a/include/block/block-io.h b/include/block/block-io.h

index 9c36a16a1f..8f5e75756a 100644

--- a/include/block/block-io.h

+++ b/include/block/block-io.h

@@ -329,8 +329,7 @@ void bdrv_drained_begin(BlockDriverState *bs);

  * Quiesces a BDS like bdrv_drained_begin(), but does not wait for already

  * running requests to complete.

  */

-void bdrv_do_drained_begin_quiesce(BlockDriverState *bs,

-                                   BdrvChild *parent, bool ignore_bds_parents);

+void bdrv_do_drained_begin_quiesce(BlockDriverState *bs, BdrvChild *parent);

 /**

  * bdrv_drained_end:

-- 

2.31.1