[Xen-devel] [OSSTEST PATCH] xl guest creation: Pause 10s to work around libxl/blkback races

[Ian Jackson <ian.jackson@xxxxxxxxxxxxx>]

In ea6626f7edd9eb40a3510eaf6816a77cac4f63d0
  guest_prepare_disk: Only do the umount if we set an env var
we removed (in the usual case) a check for the guest disk
already being mounted in dom0 etc.  This check is there for
ad-hoc testing.

We removed it because it exposes what we think is an annoying race in
blkback.

Unfortunately this change seems to have made guest-rapid-restart races
worse rather than better.  Steps test-* guest-start/debian.repeat seem
to fail a lot more now.

We are in the throes of preparing the Xen 4.13 release.  These guest
restart races have existed for a long time.

Bodge this for now by adding a sleep :-/.

We do this in the xl toolstack, during domain creation.  And also in
the libvirt toolstack because that uses xl but doesn't inherit the
sleep from the Osstest module.

CC: Jürgen Groß <jgross@xxxxxxxx>
CC: Wei Liu <wl@xxxxxxx>
CC: Anthony PERARD <anthony.perard@xxxxxxxxxx>
Signed-off-by: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
---
 Osstest/Toolstack/libvirt.pm | 1 +
 Osstest/Toolstack/xl.pm      | 1 +
 2 files changed, 2 insertions(+)

diff --git a/Osstest/Toolstack/libvirt.pm b/Osstest/Toolstack/libvirt.pm
index e817f5b4..23c76cc0 100644
--- a/Osstest/Toolstack/libvirt.pm
+++ b/Osstest/Toolstack/libvirt.pm
@@ -55,6 +55,7 @@ sub create ($$) {
     my $lcfg = $cfg;
     $lcfg =~ s,/,-,g;
     $lcfg = hostnamepath($ho)."--$lcfg";
+    sleep(10);
     target_cmd_root($ho, "virsh domxml-from-native xen-xl $cfg > $cfg.xml", 
30);
     target_getfile_root($ho,60,"$cfg.xml", "$stash/$lcfg");
     target_cmd_root($ho, "virsh create --file $cfg.xml", 100);
diff --git a/Osstest/Toolstack/xl.pm b/Osstest/Toolstack/xl.pm
index 85972753..517b0f4d 100644
--- a/Osstest/Toolstack/xl.pm
+++ b/Osstest/Toolstack/xl.pm
@@ -43,6 +43,7 @@ sub destroy ($$) {
 sub _create ($$$) {
     my ($self,$gho,$options) = @_;
     my $cfg = $gho->{CfgPath};
+    sleep(10);
     target_cmd_root($self->{Host},
                    $self->{_VerboseCommand}." create $options $cfg", 100);
 }
-- 
2.11.0


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel