From 8c97c5a476d146b35b2873ef73df601216a494d9 Mon Sep 17 00:00:00 2001 From: Peter Xu Date: Fri, 6 Dec 2024 18:08:37 -0500 Subject: [PATCH] migration/block: Fix possible race with block_inactive Src QEMU sets block_inactive=true very early before the invalidation takes place. It means if something wrong happened during setting the flag but before reaching qemu_savevm_state_complete_precopy_non_iterable() where it did the invalidation work, it'll make block_inactive flag inconsistent. For example, think about when qemu_savevm_state_complete_precopy_iterable() can fail: it will have block_inactive set to true even if all block drives are active. Fix that by only update the flag after the invalidation is done. No Fixes for any commit, because it's not an issue if bdrv_activate_all() is re-entrant upon all-active disks - false positive block_inactive can bring nothing more than "trying to active the blocks but they're already active". However let's still do it right to avoid the inconsistent flag v.s. reality. Signed-off-by: Peter Xu Reviewed-by: Fabiano Rosas Message-Id: <20241206230838.1111496-6-peterx@redhat.com> Signed-off-by: Fabiano Rosas --- migration/migration.c | 9 +++------ migration/savevm.c | 2 ++ 2 files changed, 5 insertions(+), 6 deletions(-) diff --git a/migration/migration.c b/migration/migration.c index c80fc7b94c..fd42a549e6 100644 --- a/migration/migration.c +++ b/migration/migration.c @@ -2742,14 +2742,11 @@ static int migration_completion_precopy(MigrationState *s, goto out_unlock; } - /* - * Inactivate disks except in COLO, and track that we have done so in order - * to remember to reactivate them if migration fails or is cancelled. - */ - s->block_inactive = !migrate_colo(); migration_rate_set(RATE_LIMIT_DISABLED); + + /* Inactivate disks except in COLO */ ret = qemu_savevm_state_complete_precopy(s->to_dst_file, false, - s->block_inactive); + !migrate_colo()); out_unlock: bql_unlock(); return ret; diff --git a/migration/savevm.c b/migration/savevm.c index d4842b519d..3a414aff52 100644 --- a/migration/savevm.c +++ b/migration/savevm.c @@ -1558,6 +1558,8 @@ int qemu_savevm_state_complete_precopy_non_iterable(QEMUFile *f, qemu_file_set_error(f, ret); return ret; } + /* Remember that we did this */ + s->block_inactive = true; } if (!in_postcopy) { /* Postcopy stream will still be going */ -- 2.39.5