qemu-kvm/SOURCES/kvm-block-Activate-recursively-even-for-already-active-n.patch

From 0ef6691ce8964bb2bbd677756c4e594793ca3ad8 Mon Sep 17 00:00:00 2001
From: Kevin Wolf <kwolf@redhat.com>
Date: Fri, 7 Feb 2020 11:24:01 +0000
Subject: [PATCH 04/18] block: Activate recursively even for already active
 nodes

RH-Author: Kevin Wolf <kwolf@redhat.com>
Message-id: <20200207112404.25198-4-kwolf@redhat.com>
Patchwork-id: 93749
O-Subject: [RHEL-AV-8.2.0 qemu-kvm PATCH v2 3/6] block: Activate recursively even for already active nodes
Bugzilla: 1781637
RH-Acked-by: Sergio Lopez Pascual <slp@redhat.com>
RH-Acked-by: Max Reitz <mreitz@redhat.com>
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>

bdrv_invalidate_cache_all() assumes that all nodes in a given subtree
are either active or inactive when it starts. Therefore, as soon as it
arrives at an already active node, it stops.

However, this assumption is wrong. For example, it's possible to take a
snapshot of an inactive node, which results in an active overlay over an
inactive backing file. The active overlay is probably also the root node
of an inactive BlockBackend (blk->disable_perm == true).

In this case, bdrv_invalidate_cache_all() does not need to do anything
to activate the overlay node, but it still needs to recurse into the
children and the parents to make sure that after returning success,
really everything is activated.

Cc: qemu-stable@nongnu.org
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
(cherry picked from commit 7bb4941ace471fc7dd6ded4749b95b9622baa6ed)
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>
---
 block.c | 50 ++++++++++++++++++++++++--------------------------
 1 file changed, 24 insertions(+), 26 deletions(-)

diff --git a/block.c b/block.c
index 473eb6e..2e5e8b6 100644
--- a/block.c
+++ b/block.c
@@ -5335,10 +5335,6 @@ static void coroutine_fn bdrv_co_invalidate_cache(BlockDriverState *bs,
         return;
     }
 
-    if (!(bs->open_flags & BDRV_O_INACTIVE)) {
-        return;
-    }
-
     QLIST_FOREACH(child, &bs->children, next) {
         bdrv_co_invalidate_cache(child->bs, &local_err);
         if (local_err) {
@@ -5360,34 +5356,36 @@ static void coroutine_fn bdrv_co_invalidate_cache(BlockDriverState *bs,
      * just keep the extended permissions for the next time that an activation
      * of the image is tried.
      */
-    bs->open_flags &= ~BDRV_O_INACTIVE;
-    bdrv_get_cumulative_perm(bs, &perm, &shared_perm);
-    ret = bdrv_check_perm(bs, NULL, perm, shared_perm, NULL, NULL, &local_err);
-    if (ret < 0) {
-        bs->open_flags |= BDRV_O_INACTIVE;
-        error_propagate(errp, local_err);
-        return;
-    }
-    bdrv_set_perm(bs, perm, shared_perm);
-
-    if (bs->drv->bdrv_co_invalidate_cache) {
-        bs->drv->bdrv_co_invalidate_cache(bs, &local_err);
-        if (local_err) {
+    if (bs->open_flags & BDRV_O_INACTIVE) {
+        bs->open_flags &= ~BDRV_O_INACTIVE;
+        bdrv_get_cumulative_perm(bs, &perm, &shared_perm);
+        ret = bdrv_check_perm(bs, NULL, perm, shared_perm, NULL, NULL, &local_err);
+        if (ret < 0) {
             bs->open_flags |= BDRV_O_INACTIVE;
             error_propagate(errp, local_err);
             return;
         }
-    }
+        bdrv_set_perm(bs, perm, shared_perm);
 
-    FOR_EACH_DIRTY_BITMAP(bs, bm) {
-        bdrv_dirty_bitmap_skip_store(bm, false);
-    }
+        if (bs->drv->bdrv_co_invalidate_cache) {
+            bs->drv->bdrv_co_invalidate_cache(bs, &local_err);
+            if (local_err) {
+                bs->open_flags |= BDRV_O_INACTIVE;
+                error_propagate(errp, local_err);
+                return;
+            }
+        }
 
-    ret = refresh_total_sectors(bs, bs->total_sectors);
-    if (ret < 0) {
-        bs->open_flags |= BDRV_O_INACTIVE;
-        error_setg_errno(errp, -ret, "Could not refresh total sector count");
-        return;
+        FOR_EACH_DIRTY_BITMAP(bs, bm) {
+            bdrv_dirty_bitmap_skip_store(bm, false);
+        }
+
+        ret = refresh_total_sectors(bs, bs->total_sectors);
+        if (ret < 0) {
+            bs->open_flags |= BDRV_O_INACTIVE;
+            error_setg_errno(errp, -ret, "Could not refresh total sector count");
+            return;
+        }
     }
 
     QLIST_FOREACH(parent, &bs->parents, next_parent) {
-- 
1.8.3.1