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From f03758aa88454cd2efe72b7623b855331c5ee22c Mon Sep 17 00:00:00 2001
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From: Max Reitz <mreitz@redhat.com>
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Date: Fri, 1 Nov 2013 14:23:15 +0100
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Subject: [PATCH 27/81] qcow2: Restore total_sectors value in save_vmstate
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RH-Author: Max Reitz <mreitz@redhat.com>
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Message-id: <1383315797-30938-2-git-send-email-mreitz@redhat.com>
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Patchwork-id: 55216
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O-Subject: [RHEL-7.0 qemu-kvm PATCH 1/3] qcow2: Restore total_sectors value in save_vmstate
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Bugzilla: 1025740
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RH-Acked-by: Kevin Wolf <kwolf@redhat.com>
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RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
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RH-Acked-by: Alex Williamson <alex.williamson@redhat.com>
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BZ: 1025740
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Since df2a6f29a5, bdrv_co_do_writev increases the total_sectors value of
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a growable block devices on writes after the current end. This leads to
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the virtual disk apparently growing in qcow2_save_vmstate, which in turn
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affects the disk size captured by the internal snapshot taken directly
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afterwards through e.g. the HMP savevm command. Such a "grown" snapshot
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cannot be loaded after reopening the qcow2 image, since its disk size
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differs from the actual virtual disk size (writing a VM state does not
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actually increase the virtual disk size).
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Fix this by restoring total_sectors at the end of qcow2_save_vmstate.
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Signed-off-by: Max Reitz <mreitz@redhat.com>
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Reviewed-by: Eric Blake <eblake@redhat.com>
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Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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(cherry picked from commit eedff66f21e542650d895801549ce05ac108278b)
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Signed-off-by: Max Reitz <mreitz@redhat.com>
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---
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 block/qcow2.c | 6 ++++++
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 1 file changed, 6 insertions(+)
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Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
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---
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 block/qcow2.c |    6 ++++++
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 1 files changed, 6 insertions(+), 0 deletions(-)
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diff --git a/block/qcow2.c b/block/qcow2.c
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index 8e894b9..f4adf35 100644
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--- a/block/qcow2.c
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+++ b/block/qcow2.c
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@@ -1716,6 +1716,7 @@ static int qcow2_save_vmstate(BlockDriverState *bs, QEMUIOVector *qiov,
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                               int64_t pos)
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 {
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     BDRVQcowState *s = bs->opaque;
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+    int64_t total_sectors = bs->total_sectors;
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     int growable = bs->growable;
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     int ret;
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@@ -1724,6 +1725,11 @@ static int qcow2_save_vmstate(BlockDriverState *bs, QEMUIOVector *qiov,
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     ret = bdrv_pwritev(bs, qcow2_vm_state_offset(s) + pos, qiov);
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     bs->growable = growable;
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+    /* bdrv_co_do_writev will have increased the total_sectors value to include
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+     * the VM state - the VM state is however not an actual part of the block
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+     * device, therefore, we need to restore the old value. */
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+    bs->total_sectors = total_sectors;
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+
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     return ret;
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 }
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-- 
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1.7.1
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