From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53479) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cUDr7-0007qw-6J for qemu-devel@nongnu.org; Thu, 19 Jan 2017 09:38:26 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cUDr2-000333-Ur for qemu-devel@nongnu.org; Thu, 19 Jan 2017 09:38:25 -0500 From: zhanghailiang Date: Thu, 19 Jan 2017 22:37:47 +0800 Message-ID: <1484836667-26460-1-git-send-email-zhang.zhanghailiang@huawei.com> MIME-Version: 1.0 Content-Type: text/plain Subject: [Qemu-devel] [PATCH] migration: re-active images while migration been canceled after inactive them List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: amit.shah@redhat.com, quintela@redhat.com, dgilbert@redhat.com, kwolf@redhat.com, qemu-block@nongnu.org, xuquan8@huawei.com, zhanghailiang 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. Signed-off-by: zhanghailiang --- Hi, I have sent another patch before to fix this problem, but didn't cover all the scenes, and there are some discussions about this problem, For more detail, please refer to https://lists.gnu.org/archive/html/qemu-block/2016-12/msg00003.html --- include/migration/migration.h | 3 +++ migration/migration.c | 13 +++++++++++++ 2 files changed, 16 insertions(+) diff --git a/include/migration/migration.h b/include/migration/migration.h index c309d23..2d5b724 100644 --- a/include/migration/migration.h +++ b/include/migration/migration.h @@ -177,6 +177,9 @@ 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 f498ab8..9defb3e 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) @@ -1705,6 +1715,7 @@ 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(); @@ -1758,6 +1769,8 @@ fail_invalidate: bdrv_invalidate_cache_all(&local_err); if (local_err) { error_report_err(local_err); + } else { + s->block_inactive = false; } } -- 1.8.3.1