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From ceea60585e2975d7860725bb8c6c860b791a4b72 Mon Sep 17 00:00:00 2001
From: Kevin Wolf <kwolf@redhat.com>
Date: Mon, 17 Mar 2014 13:29:26 +0100
Subject: [PATCH 2/6] block: Update image size in bdrv_invalidate_cache()

RH-Author: Kevin Wolf <kwolf@redhat.com>
Message-id: <1395062967-16867-2-git-send-email-kwolf@redhat.com>
Patchwork-id: 58111
O-Subject: [RHEL-7.0 qemu-kvm PATCH 1/2] block: Update image size in bdrv_invalidate_cache()
Bugzilla: 1048575
RH-Acked-by: Max Reitz <mreitz@redhat.com>
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
RH-Acked-by: Fam Zheng <famz@redhat.com>

After migration has completed, we call bdrv_invalidate_cache() so that
drivers which cache some data drop their stale copy of the data and
reread it from the image file to get a new version of data that the
source modified while the migration was running.

Reloading metadata from the image file is useless, though, if the size
of the image file stays stale (this is a value that is cached for all
image formats in block.c). Reads from (meta)data after the old EOF
return only zeroes, causing image corruption.

We need to update bs->total_sectors in all layers that could potentially
have changed their size (i.e. backing files are not a concern - if they
are changed, we're in bigger trouble)

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
(cherry picked from commit 3456a8d1852e970688b73d03fdc44dde851759e1)
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 block.c       | 10 +++++++++-
 block/qcow2.c |  2 ++
 block/qed.c   |  3 +++
 3 files changed, 14 insertions(+), 1 deletion(-)

Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
 block.c       |   10 +++++++++-
 block/qcow2.c |    2 ++
 block/qed.c   |    3 +++
 3 files changed, 14 insertions(+), 1 deletions(-)

diff --git a/block.c b/block.c
index ec8dc90..ae55535 100644
--- a/block.c
+++ b/block.c
@@ -4713,9 +4713,17 @@ flush_parent:
 
 void bdrv_invalidate_cache(BlockDriverState *bs)
 {
-    if (bs->drv && bs->drv->bdrv_invalidate_cache) {
+    if (!bs->drv)  {
+        return;
+    }
+
+    if (bs->drv->bdrv_invalidate_cache) {
         bs->drv->bdrv_invalidate_cache(bs);
+    } else if (bs->file) {
+        bdrv_invalidate_cache(bs->file);
     }
+
+    refresh_total_sectors(bs, bs->total_sectors);
 }
 
 void bdrv_invalidate_cache_all(void)
diff --git a/block/qcow2.c b/block/qcow2.c
index daad932..e9bd9c9 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -1176,6 +1176,8 @@ static void qcow2_invalidate_cache(BlockDriverState *bs)
 
     qcow2_close(bs);
 
+    bdrv_invalidate_cache(bs->file);
+
     options = qdict_new();
     qdict_put(options, QCOW2_OPT_LAZY_REFCOUNTS,
               qbool_from_int(s->use_lazy_refcounts));
diff --git a/block/qed.c b/block/qed.c
index be5945b..619f2d0 100644
--- a/block/qed.c
+++ b/block/qed.c
@@ -1561,6 +1561,9 @@ static void bdrv_qed_invalidate_cache(BlockDriverState *bs)
     BDRVQEDState *s = bs->opaque;
 
     bdrv_qed_close(bs);
+
+    bdrv_invalidate_cache(bs->file);
+
     memset(s, 0, sizeof(BDRVQEDState));
     bdrv_qed_open(bs, NULL, bs->open_flags, NULL);
 }
-- 
1.7.1