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migration: Don't activate block devices if using -S

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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 <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
This commit is contained in:
Dr. David Alan Gilbert 2018-04-16 18:09:30 +01:00 committed by Juan Quintela
parent b895de5027
commit 0f073f44df
2 changed files with 32 additions and 8 deletions
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20
migration/migration.c
View File

@ -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. * Called on -incoming with a defer: uri.
* The migration can be started later after any parameters have been * The migration can be started later after any parameters have been
@ -311,6 +321,15 @@ static void process_incoming_migration_bh(void *opaque)
Error *local_err = NULL; Error *local_err = NULL;
MigrationIncomingState *mis = opaque; MigrationIncomingState *mis = opaque;
/* 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. /* Make sure all file formats flush their mutable metadata.
* If we get an error here, just don't restart the VM yet. */ * If we get an error here, just don't restart the VM yet. */
bdrv_invalidate_cache_all(&local_err); bdrv_invalidate_cache_all(&local_err);
@ -319,6 +338,7 @@ static void process_incoming_migration_bh(void *opaque)
local_err = NULL; local_err = NULL;
autostart = false; autostart = false;
} }
}
/* /*
* This must happen after all error conditions are dealt with and * This must happen after all error conditions are dealt with and

6
qapi/migration.json
View File

@ -376,13 +376,17 @@
# @postcopy-blocktime: Calculate downtime for postcopy live migration # @postcopy-blocktime: Calculate downtime for postcopy live migration
# (since 3.0) # (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 # Since: 1.2
## ##
{ 'enum': 'MigrationCapability', { 'enum': 'MigrationCapability',
'data': ['xbzrle', 'rdma-pin-all', 'auto-converge', 'zero-blocks', 'data': ['xbzrle', 'rdma-pin-all', 'auto-converge', 'zero-blocks',
'compress', 'events', 'postcopy-ram', 'x-colo', 'release-ram', 'compress', 'events', 'postcopy-ram', 'x-colo', 'release-ram',
'block', 'return-path', 'pause-before-switchover', 'x-multifd', 'block', 'return-path', 'pause-before-switchover', 'x-multifd',
'dirty-bitmaps', 'postcopy-blocktime' ] } 'dirty-bitmaps', 'postcopy-blocktime', 'late-block-activate' ] }
## ##
# @MigrationCapabilityStatus: # @MigrationCapabilityStatus: