From 1d2acc3162d9c7772510c973f446353fbdd1f9a8 Mon Sep 17 00:00:00 2001 From: zhanghailiang Date: Tue, 24 Jan 2017 15:59:52 +0800 Subject: migration: re-active images while migration been canceled after inactive them commit fe904ea8242cbae2d7e69c052c754b8f5f1ba1d6 fixed a case which migration aborted QEMU because it didn't regain the control of images while some errors happened. Actually, there are another two cases can trigger the same error reports: " bdrv_co_do_pwritev: Assertion `!(bs->open_flags & 0x0800)' failed", Case 1, codes path: migration_thread() migration_completion() bdrv_inactivate_all() ----------------> inactivate images qemu_savevm_state_complete_precopy() socket_writev_buffer() --------> error because destination fails qemu_fflush() ----------------> set error on migration stream -> qmp_migrate_cancel() ----------------> user cancelled migration concurrently -> migrate_set_state() ------------------> set migrate CANCELLIN migration_completion() -----------------> go on to fail_invalidate if (s->state == MIGRATION_STATUS_ACTIVE) -> Jump this branch Case 2, codes path: migration_thread() migration_completion() bdrv_inactivate_all() ----------------> inactivate images migreation_completion() finished -> qmp_migrate_cancel() ---------------> user cancelled migration concurrently qemu_mutex_lock_iothread(); qemu_bh_schedule (s->cleanup_bh); As we can see from above, qmp_migrate_cancel can slip in whenever migration_thread does not hold the global lock. If this happens after bdrv_inactive_all() been called, the above error reports will appear. To prevent this, we can call bdrv_invalidate_cache_all() in qmp_migrate_cancel() directly if we find images become inactive. Besides, bdrv_invalidate_cache_all() in migration_completion() doesn't have the protection of big lock, fix it by add the missing qemu_mutex_lock_iothread(); Signed-off-by: zhanghailiang Message-Id: <1485244792-11248-1-git-send-email-zhang.zhanghailiang@huawei.com> Reviewed-by: Dr. David Alan Gilbert Reviewed-by: Stefan Hajnoczi Signed-off-by: Dr. David Alan Gilbert --- include/migration/migration.h | 3 +++ migration/migration.c | 15 +++++++++++++++ 2 files changed, 18 insertions(+) diff --git a/include/migration/migration.h b/include/migration/migration.h index 7881e8925b..af9135f0a7 100644 --- a/include/migration/migration.h +++ b/include/migration/migration.h @@ -180,6 +180,9 @@ struct MigrationState /* Flag set once the migration thread is running (and needs joining) */ bool migration_thread_running; + /* Flag set once the migration thread called bdrv_inactivate_all */ + bool block_inactive; + /* Queue of outstanding page requests from the destination */ QemuMutex src_page_req_mutex; QSIMPLEQ_HEAD(src_page_requests, MigrationSrcPageRequest) src_page_requests; diff --git a/migration/migration.c b/migration/migration.c index 7dcb7d7a32..f8a4500cd1 100644 --- a/migration/migration.c +++ b/migration/migration.c @@ -1006,6 +1006,16 @@ static void migrate_fd_cancel(MigrationState *s) if (s->state == MIGRATION_STATUS_CANCELLING && f) { qemu_file_shutdown(f); } + if (s->state == MIGRATION_STATUS_CANCELLING && s->block_inactive) { + Error *local_err = NULL; + + bdrv_invalidate_cache_all(&local_err); + if (local_err) { + error_report_err(local_err); + } else { + s->block_inactive = false; + } + } } void add_migration_state_change_notifier(Notifier *notify) @@ -1745,6 +1755,7 @@ static void migration_completion(MigrationState *s, int current_active_state, if (ret >= 0) { qemu_file_set_rate_limit(s->to_dst_file, INT64_MAX); qemu_savevm_state_complete_precopy(s->to_dst_file, false); + s->block_inactive = true; } } qemu_mutex_unlock_iothread(); @@ -1795,10 +1806,14 @@ fail_invalidate: if (s->state == MIGRATION_STATUS_ACTIVE) { Error *local_err = NULL; + qemu_mutex_lock_iothread(); bdrv_invalidate_cache_all(&local_err); if (local_err) { error_report_err(local_err); + } else { + s->block_inactive = false; } + qemu_mutex_unlock_iothread(); } fail: -- cgit v1.2.3