qemu-kvm/kvm-block-Remove-ignore_bds_parents-parameter-from-drain.patch

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