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From b8159f39be879b1133ce89bcb2c892e0d6711fdb Mon Sep 17 00:00:00 2001
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From: Max Reitz <mreitz@redhat.com>
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Date: Sun, 22 Dec 2013 16:12:39 +0100
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Subject: [PATCH 1/8] block/stream: Don't stream unbacked devices
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RH-Author: Max Reitz <mreitz@redhat.com>
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Message-id: <1387728759-7141-2-git-send-email-mreitz@redhat.com>
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Patchwork-id: 56422
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O-Subject: [RHEL-7.0 qemu-kvm PATCH] block/stream: Don't stream unbacked devices
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Bugzilla: 965636
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RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
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RH-Acked-by: Fam Zheng <famz@redhat.com>
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RH-Acked-by: Kevin Wolf <kwolf@redhat.com>
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BZ: 965636
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If a block device is unbacked, a streaming blockjob should immediately
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finish instead of beginning to try to stream, then noticing the backing
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file does not contain even the first sector (since it does not exist)
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and then finishing normally.
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Signed-off-by: Max Reitz <mreitz@redhat.com>
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Reviewed-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com>
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Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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(cherry picked from commit f4a193e717e6b5179a2e57423bfe110b724662d8)
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Signed-off-by: Max Reitz <mreitz@redhat.com>
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---
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 block/stream.c | 5 +++++
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 1 file changed, 5 insertions(+)
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Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
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---
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 block/stream.c |    5 +++++
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 1 files changed, 5 insertions(+), 0 deletions(-)
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diff --git a/block/stream.c b/block/stream.c
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index 276487c..cbae815 100644
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--- a/block/stream.c
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+++ b/block/stream.c
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@@ -84,6 +84,11 @@ static void coroutine_fn stream_run(void *opaque)
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     int n = 0;
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     void *buf;
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+    if (!bs->backing_hd) {
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+        block_job_completed(&s->common, 0);
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+        return;
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+    }
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+
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     s->common.len = bdrv_getlength(bs);
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     if (s->common.len < 0) {
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         block_job_completed(&s->common, s->common.len);
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-- 
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1.7.1
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