Blame SOURCES/kvm-savevm-fail-if-migration-blockers-are-present.patch

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From 51568d18bbfef1adce26d8cd33f3f4a4c12b1e78 Mon Sep 17 00:00:00 2001
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From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
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Date: Fri, 26 Jan 2018 18:53:15 +0100
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Subject: [PATCH 4/4] savevm: fail if migration blockers are present
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RH-Author: Dr. David Alan Gilbert <dgilbert@redhat.com>
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Message-id: <20180126185315.2342-3-dgilbert@redhat.com>
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Patchwork-id: 78732
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O-Subject: [RHEL7.5 qemu-kvm PATCH 2/2] savevm: fail if migration blockers are present
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Bugzilla: 1536883
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RH-Acked-by: Peter Xu <peterx@redhat.com>
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RH-Acked-by: Kevin Wolf <kwolf@redhat.com>
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RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>
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From: Greg Kurz <gkurz@linux.vnet.ibm.com>
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QEMU has currently two ways to prevent migration to occur:
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- migration blocker when it depends on runtime state
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- VMStateDescription.unmigratable when migration is not supported at all
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This patch gathers all the logic into a single function to be called from
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both the savevm and the migrate paths.
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This fixes a bug with 9p, at least, where savevm would succeed and the
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following would happen in the guest after loadvm:
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$ ls /host
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ls: cannot access /host: Protocol error
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With this patch:
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(qemu) savevm foo
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Migration is disabled when VirtFS export path '/' is mounted in the guest
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using mount_tag 'host'
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Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
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Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
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Message-Id: <146239057139.11271.9011797645454781543.stgit@bahia.huguette.org>
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[Update subject according to Paolo's suggestion - Amit]
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(cherry picked from commit 24f3902b088cd4f2dbebfd90527b5d81d6a050e9)
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  dgilbert: Manual merge
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Signed-off-by: Amit Shah <amit.shah@redhat.com>
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Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
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---
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 include/migration/migration.h |  1 +
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 migration.c                   | 21 +++++++++++++++------
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 savevm.c                      |  2 +-
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 3 files changed, 17 insertions(+), 7 deletions(-)
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diff --git a/include/migration/migration.h b/include/migration/migration.h
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index c99a67c..0760984 100644
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--- a/include/migration/migration.h
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+++ b/include/migration/migration.h
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@@ -90,6 +90,7 @@ int migrate_fd_close(MigrationState *s);
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 void add_migration_state_change_notifier(Notifier *notify);
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 void remove_migration_state_change_notifier(Notifier *notify);
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+bool migration_is_blocked(Error **errp);
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 bool migration_in_setup(MigrationState *);
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 bool migration_has_finished(MigrationState *);
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 bool migration_has_failed(MigrationState *);
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diff --git a/migration.c b/migration.c
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index e8c5939..5591601 100644
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--- a/migration.c
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+++ b/migration.c
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@@ -417,6 +417,20 @@ void migrate_del_blocker(Error *reason)
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     migration_blockers = g_slist_remove(migration_blockers, reason);
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 }
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+bool migration_is_blocked(Error **errp)
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+{
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+    if (qemu_savevm_state_blocked(errp)) {
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+        return true;
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+    }
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+
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+    if (migration_blockers) {
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+        *errp = error_copy(migration_blockers->data);
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+        return true;
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+    }
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+
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+    return false;
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+}
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+
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 void qmp_migrate(const char *uri, bool has_blk, bool blk,
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                  bool has_inc, bool inc, bool has_detach, bool detach,
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                  Error **errp)
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@@ -447,12 +461,7 @@ void qmp_migrate(const char *uri, bool has_blk, bool blk,
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         return;
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     }
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-    if (qemu_savevm_state_blocked(errp)) {
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-        return;
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-    }
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-
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-    if (migration_blockers) {
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-        *errp = error_copy(migration_blockers->data);
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+    if (migration_is_blocked(errp)) {
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         return;
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     }
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diff --git a/savevm.c b/savevm.c
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index d34004e..0216df2 100644
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--- a/savevm.c
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+++ b/savevm.c
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@@ -2207,7 +2207,7 @@ static int qemu_savevm_state(QEMUFile *f, Error **errp)
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         .shared = 0
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     };
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-    if (qemu_savevm_state_blocked(errp)) {
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+    if (migration_is_blocked(errp)) {
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         return -EINVAL;
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     }
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-- 
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1.8.3.1
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