From 7ea2d269cb84ca7a2f4b7c3735634176f7c1dc35 Mon Sep 17 00:00:00 2001 From: Alexey Kardashevskiy Date: Thu, 9 Oct 2014 13:50:46 +1100 Subject: [PATCH] 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 Reviewed-by: Paolo Bonzini -- fixed parens by hand Signed-off-by: Juan Quintela --- block.c | 18 +++++------------- migration.c | 1 - nbd.c | 6 ++++++ 3 files changed, 11 insertions(+), 14 deletions(-) diff --git a/block.c b/block.c index d3aebeb..27533f3 100644 --- a/block.c +++ b/block.c @@ -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; diff --git a/migration.c b/migration.c index 8d675b3..c49a05a 100644 --- a/migration.c +++ b/migration.c @@ -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) { diff --git a/nbd.c b/nbd.c index e9b539b..a7bce45 100644 --- a/nbd.c +++ b/nbd.c @@ -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; } -- 2.7.4