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[Qemu-devel] [PULL 3/5] migration: Don't activate block devices if using
From: |
Juan Quintela |
Subject: |
[Qemu-devel] [PULL 3/5] migration: Don't activate block devices if using -S |
Date: |
Mon, 4 Jun 2018 06:21:54 +0200 |
From: "Dr. David Alan Gilbert" <address@hidden>
Activating the block devices causes the locks to be taken on
the backing file. If we're running with -S and the destination libvirt
hasn't started the destination with 'cont', it's expecting the locks are
still untaken.
Don't activate the block devices if we're not going to autostart the VM;
'cont' already will do that anyway. This change is tied to the new
migration capability 'late-block-activate' that defaults to off, keeping
the old behaviour by default.
bz: https://bugzilla.redhat.com/show_bug.cgi?id=1560854
Signed-off-by: Dr. David Alan Gilbert <address@hidden>
Reviewed-by: Juan Quintela <address@hidden>
Signed-off-by: Juan Quintela <address@hidden>
---
migration/migration.c | 34 +++++++++++++++++++++++++++-------
qapi/migration.json | 6 +++++-
2 files changed, 32 insertions(+), 8 deletions(-)
diff --git a/migration/migration.c b/migration/migration.c
index a5384865ff..1e99ec9b7e 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -202,6 +202,16 @@ static void migrate_generate_event(int new_state)
}
}
+static bool migrate_late_block_activate(void)
+{
+ MigrationState *s;
+
+ s = migrate_get_current();
+
+ return s->enabled_capabilities[
+ MIGRATION_CAPABILITY_LATE_BLOCK_ACTIVATE];
+}
+
/*
* Called on -incoming with a defer: uri.
* The migration can be started later after any parameters have been
@@ -311,13 +321,23 @@ static void process_incoming_migration_bh(void *opaque)
Error *local_err = NULL;
MigrationIncomingState *mis = opaque;
- /* Make sure all file formats flush their mutable metadata.
- * If we get an error here, just don't restart the VM yet. */
- bdrv_invalidate_cache_all(&local_err);
- if (local_err) {
- error_report_err(local_err);
- local_err = NULL;
- autostart = false;
+ /* If capability late_block_activate is set:
+ * Only fire up the block code now if we're going to restart the
+ * VM, else 'cont' will do it.
+ * This causes file locking to happen; so we don't want it to happen
+ * unless we really are starting the VM.
+ */
+ if (!migrate_late_block_activate() ||
+ (autostart && (!global_state_received() ||
+ global_state_get_runstate() == RUN_STATE_RUNNING))) {
+ /* Make sure all file formats flush their mutable metadata.
+ * If we get an error here, just don't restart the VM yet. */
+ bdrv_invalidate_cache_all(&local_err);
+ if (local_err) {
+ error_report_err(local_err);
+ local_err = NULL;
+ autostart = false;
+ }
}
/*
diff --git a/qapi/migration.json b/qapi/migration.json
index dc9cc85545..f7e10ee90f 100644
--- a/qapi/migration.json
+++ b/qapi/migration.json
@@ -376,13 +376,17 @@
# @postcopy-blocktime: Calculate downtime for postcopy live migration
# (since 3.0)
#
+# @late-block-activate: If enabled, the destination will not activate block
+# devices (and thus take locks) immediately at the end of migration.
+# (since 3.0)
+#
# Since: 1.2
##
{ 'enum': 'MigrationCapability',
'data': ['xbzrle', 'rdma-pin-all', 'auto-converge', 'zero-blocks',
'compress', 'events', 'postcopy-ram', 'x-colo', 'release-ram',
'block', 'return-path', 'pause-before-switchover', 'x-multifd',
- 'dirty-bitmaps', 'postcopy-blocktime' ] }
+ 'dirty-bitmaps', 'postcopy-blocktime', 'late-block-activate' ] }
##
# @MigrationCapabilityStatus:
--
2.17.0
- [Qemu-devel] [PULL 0/5] Migration pull request, Juan Quintela, 2018/06/04
- [Qemu-devel] [PULL 1/5] migration: introduce decompress-error-check, Juan Quintela, 2018/06/04
- [Qemu-devel] [PULL 2/5] migration: discard non-migratable RAMBlocks, Juan Quintela, 2018/06/04
- [Qemu-devel] [PULL 3/5] migration: Don't activate block devices if using -S,
Juan Quintela <=
- [Qemu-devel] [PULL 4/5] migration: remove unnecessary variables len in QIOChannelRDMA, Juan Quintela, 2018/06/04
- [Qemu-devel] [PULL 5/5] migration: not wait RDMA_CM_EVENT_DISCONNECTED event after rdma_disconnect, Juan Quintela, 2018/06/04
- Re: [Qemu-devel] [PULL 0/5] Migration pull request, no-reply, 2018/06/04
- Re: [Qemu-devel] [PULL 0/5] Migration pull request, Peter Maydell, 2018/06/04