| Message ID | 1485244792-11248-1-git-send-email-zhang.zhanghailiang@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
* zhanghailiang (zhang.zhanghailiang@huawei.com) wrote: > 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 <zhang.zhanghailiang@huawei.com> Yes, I think tht's better: Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> > --- > v2: > - Fix a bug introduced by commit fe904 which didn't get big lock > before call bdrv_invalidate_cache_all. (Suggested by Dave) > --- > 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 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..5b50afe 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(); > @@ -1755,10 +1766,14 @@ 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: > -- > 1.8.3.1 > > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
* zhanghailiang (zhang.zhanghailiang@huawei.com) wrote: > 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", Queued. Dave > > 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 <zhang.zhanghailiang@huawei.com> > --- > v2: > - Fix a bug introduced by commit fe904 which didn't get big lock > before call bdrv_invalidate_cache_all. (Suggested by Dave) > --- > 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 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..5b50afe 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(); > @@ -1755,10 +1766,14 @@ 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: > -- > 1.8.3.1 > > > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
On Tue, Jan 24, 2017 at 03:59:52PM +0800, zhanghailiang wrote: > 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 <zhang.zhanghailiang@huawei.com> > --- > v2: > - Fix a bug introduced by commit fe904 which didn't get big lock > before call bdrv_invalidate_cache_all. (Suggested by Dave) > --- > include/migration/migration.h | 3 +++ > migration/migration.c | 15 +++++++++++++++ > 2 files changed, 18 insertions(+) Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
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..5b50afe 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(); @@ -1755,10 +1766,14 @@ 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:
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 <zhang.zhanghailiang@huawei.com> --- v2: - Fix a bug introduced by commit fe904 which didn't get big lock before call bdrv_invalidate_cache_all. (Suggested by Dave) --- include/migration/migration.h | 3 +++ migration/migration.c | 15 +++++++++++++++ 2 files changed, 18 insertions(+)