46 lines
1.8 KiB
Diff
46 lines
1.8 KiB
Diff
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From 2a3b0da09e3a89eb9a6c84fd6015367ba3022e24 Mon Sep 17 00:00:00 2001
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From: "Richard W.M. Jones" <rjones@redhat.com>
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Date: Tue, 25 Jan 2022 10:06:37 +0000
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Subject: [PATCH] input: libvirt: Share a single connection to the source NBD
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server
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When using virt-p2v from RHEL 7, it starts a very old qemu-nbd server
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(probably 1.5.3) which required the --shared parameter to enable
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sharing even in read-only mode. Since it doesn't pass this parameter
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only a single connection at a time is allowed, and further connections
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will deadlock. Note that later versions of qemu-nbd changed this so
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that read-only connections permit sharing automatically.
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In modular virt-v2v we now use nbdkit-nbd-plugin to proxy the
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connection to virt-p2v / qemu-nbd. When you connect to this multiple
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times, as virt-v2v does, it will make multiple connections to the
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backend qemu-nbd. This will cause a deadlock.
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We can use the nbdkit-nbd-plugin shared=true flag to enable the plugin
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to share a single connection to the backend between multiple nbdkit
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clients.
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Reported-by: Tingting Zheng
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Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=2044911
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Reviewed-by: Laszlo Ersek <lersek@redhat.com>
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(cherry picked from commit 20019b5cadc1434ac09842e2045a7d5635561835)
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---
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input/input_libvirt.ml | 1 +
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1 file changed, 1 insertion(+)
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diff --git a/input/input_libvirt.ml b/input/input_libvirt.ml
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index 33f61086..42050c15 100644
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--- a/input/input_libvirt.ml
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+++ b/input/input_libvirt.ml
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@@ -76,6 +76,7 @@ and libvirt_servers dir disks =
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Nbdkit.add_filter cmd "cow";
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Nbdkit.add_arg cmd "hostname" hostname;
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Nbdkit.add_arg cmd "port" (string_of_int port);
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+ Nbdkit.add_arg cmd "shared" "true";
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let _, pid = Nbdkit.run_unix ~socket cmd in
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(* --exit-with-parent should ensure nbdkit is cleaned
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--
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2.31.1
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