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block/migration: Disable cache invalidate for incoming migration 

When migrated using libvirt with "--copy-storage-all", at the end of
migration there is race between NBD mirroring task trying to do flush
and migration completion, both end up invalidating cache. Since qcow2
driver does not handle this situation very well, random crashes happen.

This disables the BDRV_O_INCOMING flag for the block device being migrated
once the cache has been invalidated.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>

--

fixed parens by hand
Signed-off-by: Juan Quintela <quintela@redhat.com>
This commit is contained in:
Alexey Kardashevskiy 2014-10-09 13:50:46 +11:00 committed by Juan Quintela
parent 9935baca9b
commit 7ea2d269cb
3 changed files with 11 additions and 14 deletions
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18
block.c
View File

@ -5043,6 +5043,11 @@ void bdrv_invalidate_cache(BlockDriverState *bs, Error **errp)
return;
}
if (!(bs->open_flags & BDRV_O_INCOMING)) {
return;
}
bs->open_flags &= ~BDRV_O_INCOMING;
if (bs->drv->bdrv_invalidate_cache) {
bs->drv->bdrv_invalidate_cache(bs, &local_err);
} else if (bs->file) {
@ -5078,19 +5083,6 @@ void bdrv_invalidate_cache_all(Error **errp)
}
}
void bdrv_clear_incoming_migration_all(void)
{
BlockDriverState *bs;
QTAILQ_FOREACH(bs, &bdrv_states, device_list) {
AioContext *aio_context = bdrv_get_aio_context(bs);
aio_context_acquire(aio_context);
bs->open_flags = bs->open_flags & ~(BDRV_O_INCOMING);
aio_context_release(aio_context);
}
}
int bdrv_flush(BlockDriverState *bs)
{
Coroutine *co;

1
migration.c
View File

@ -103,7 +103,6 @@ static void process_incoming_migration_co(void *opaque)
}
qemu_announce_self();
bdrv_clear_incoming_migration_all();
/* Make sure all file formats flush their mutable metadata */
bdrv_invalidate_cache_all(&local_err);
if (local_err) {

6
nbd.c
View File

@ -972,6 +972,12 @@ NBDExport *nbd_export_new(BlockDriverState *bs, off_t dev_offset,
exp->ctx = bdrv_get_aio_context(bs);
bdrv_ref(bs);
bdrv_add_aio_context_notifier(bs, bs_aio_attached, bs_aio_detach, exp);
/*
* NBD exports are used for non-shared storage migration. Make sure
* that BDRV_O_INCOMING is cleared and the image is ready for write
* access since the export could be available before migration handover.
*/
bdrv_invalidate_cache(bs, NULL);
return exp;
}