* [Qemu-devel] [PATCH v2] migration: re-active images while migration been canceled after inactive them
@ 2017-01-24 7:59 zhanghailiang
2017-01-24 10:47 ` Dr. David Alan Gilbert
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: zhanghailiang @ 2017-01-24 7:59 UTC (permalink / raw)
To: qemu-devel
Cc: qemu-block, kwolf, dgilbert, amit.shah, quintela, 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.
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
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [Qemu-devel] [PATCH v2] migration: re-active images while migration been canceled after inactive them
2017-01-24 7:59 [Qemu-devel] [PATCH v2] migration: re-active images while migration been canceled after inactive them zhanghailiang
@ 2017-01-24 10:47 ` Dr. David Alan Gilbert
2017-01-24 11:52 ` Dr. David Alan Gilbert
2017-01-24 12:53 ` [Qemu-devel] [Qemu-block] " Stefan Hajnoczi
2 siblings, 0 replies; 4+ messages in thread
From: Dr. David Alan Gilbert @ 2017-01-24 10:47 UTC (permalink / raw)
To: zhanghailiang; +Cc: qemu-devel, qemu-block, kwolf, amit.shah, quintela
* 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
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [Qemu-devel] [PATCH v2] migration: re-active images while migration been canceled after inactive them
2017-01-24 7:59 [Qemu-devel] [PATCH v2] migration: re-active images while migration been canceled after inactive them zhanghailiang
2017-01-24 10:47 ` Dr. David Alan Gilbert
@ 2017-01-24 11:52 ` Dr. David Alan Gilbert
2017-01-24 12:53 ` [Qemu-devel] [Qemu-block] " Stefan Hajnoczi
2 siblings, 0 replies; 4+ messages in thread
From: Dr. David Alan Gilbert @ 2017-01-24 11:52 UTC (permalink / raw)
To: zhanghailiang; +Cc: qemu-devel, qemu-block, kwolf, amit.shah, quintela
* 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
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [Qemu-devel] [Qemu-block] [PATCH v2] migration: re-active images while migration been canceled after inactive them
2017-01-24 7:59 [Qemu-devel] [PATCH v2] migration: re-active images while migration been canceled after inactive them zhanghailiang
2017-01-24 10:47 ` Dr. David Alan Gilbert
2017-01-24 11:52 ` Dr. David Alan Gilbert
@ 2017-01-24 12:53 ` Stefan Hajnoczi
2 siblings, 0 replies; 4+ messages in thread
From: Stefan Hajnoczi @ 2017-01-24 12:53 UTC (permalink / raw)
To: zhanghailiang
Cc: qemu-devel, kwolf, qemu-block, quintela, dgilbert, amit.shah
[-- Attachment #1: Type: text/plain, Size: 2325 bytes --]
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>
[-- Attachment #2: signature.asc --]
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^ permalink raw reply [flat|nested] 4+ messages in thread
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Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2017-01-24 7:59 [Qemu-devel] [PATCH v2] migration: re-active images while migration been canceled after inactive them zhanghailiang
2017-01-24 10:47 ` Dr. David Alan Gilbert
2017-01-24 11:52 ` Dr. David Alan Gilbert
2017-01-24 12:53 ` [Qemu-devel] [Qemu-block] " Stefan Hajnoczi
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