Re: [Qemu-block] [PATCH] block: Cleanup BMDS in bdrv_close_all

2017-09-05 Thread Stefan Hajnoczi 
On Tue, Sep 05, 2017 at 11:28:44AM +0100, Stefan Hajnoczi wrote:
> On Wed, Aug 30, 2017 at 06:06:05PM +0800, Fam Zheng wrote:
> > This fixes the assertion due to op blockers added by BMDS:
> > 
> > block.c:3248: bdrv_delete: Assertion `bdrv_op_blocker_is_empty(bs)' failed.
> > 
> > Reproducer: simply start block migration and quit QEMU before it ends.
> > 
> > Cc: qemu-sta...@nongnu.org
> > Signed-off-by: Fam Zheng 
> > ---
> >  block.c | 2 ++
> >  migration/block.c   | 2 +-
> >  migration/block.h   | 1 +
> >  stubs/Makefile.objs | 1 +
> >  stubs/block-migration.c | 6 ++
> >  5 files changed, 11 insertions(+), 1 deletion(-)
> >  create mode 100644 stubs/block-migration.c
> 
> Thanks, applied to my block tree:
> https://github.com/stefanha/qemu/commits/block

Dropped again pending the issue Kevin raised.

Stefan

Re: [Qemu-block] [PATCH] block: Cleanup BMDS in bdrv_close_all

2017-09-05 Thread Stefan Hajnoczi 
On Wed, Aug 30, 2017 at 06:06:05PM +0800, Fam Zheng wrote:
> This fixes the assertion due to op blockers added by BMDS:
> 
> block.c:3248: bdrv_delete: Assertion `bdrv_op_blocker_is_empty(bs)' failed.
> 
> Reproducer: simply start block migration and quit QEMU before it ends.
> 
> Cc: qemu-sta...@nongnu.org
> Signed-off-by: Fam Zheng 
> ---
>  block.c | 2 ++
>  migration/block.c   | 2 +-
>  migration/block.h   | 1 +
>  stubs/Makefile.objs | 1 +
>  stubs/block-migration.c | 6 ++
>  5 files changed, 11 insertions(+), 1 deletion(-)
>  create mode 100644 stubs/block-migration.c

Thanks, applied to my block tree:
https://github.com/stefanha/qemu/commits/block

Stefan

Re: [Qemu-block] [PATCH] block: Cleanup BMDS in bdrv_close_all

2017-09-05 Thread Juan Quintela 
Kevin Wolf  wrote:
> Am 05.09.2017 um 10:54 hat Fam Zheng geschrieben:
>> On Tue, 09/05 10:44, Kevin Wolf wrote:
>> > Am 30.08.2017 um 12:06 hat Fam Zheng geschrieben:
>> > > This fixes the assertion due to op blockers added by BMDS:
>> > > 
>> > > block.c:3248: bdrv_delete: Assertion `bdrv_op_blocker_is_empty(bs)' 
>> > > failed.
>> > > 
>> > > Reproducer: simply start block migration and quit QEMU before it ends.
>> > > 
>> > > Cc: qemu-sta...@nongnu.org
>> > > Signed-off-by: Fam Zheng 
>> > > ---
>> > >  block.c | 2 ++
>> > >  migration/block.c   | 2 +-
>> > >  migration/block.h   | 1 +
>> > >  stubs/Makefile.objs | 1 +
>> > >  stubs/block-migration.c | 6 ++
>> > >  5 files changed, 11 insertions(+), 1 deletion(-)
>> > >  create mode 100644 stubs/block-migration.c
>> > > 
>> > > diff --git a/block.c b/block.c
>> > > index 3308814bba..508a57274d 100644
>> > > --- a/block.c
>> > > +++ b/block.c
>> > > @@ -43,6 +43,7 @@
>> > >  #include "qemu/cutils.h"
>> > >  #include "qemu/id.h"
>> > >  #include "qapi/util.h"
>> > > +#include "migration/block.h"
>> > >  
>> > >  #ifdef CONFIG_BSD
>> > >  #include 
>> > > @@ -3111,6 +3112,7 @@ static void bdrv_close(BlockDriverState *bs)
>> > >  
>> > >  void bdrv_close_all(void)
>> > >  {
>> > > +block_migration_cleanup_bmds();
>> > >  block_job_cancel_sync_all();
>> > >  nbd_export_close_all();
>> > 
>> > This is before bdrv_drain_all(). Can't we still have a block migration
>> > request in flight, whose callback will then dereference a stale pointer?
>> 
>> You're right, bdrv_drain_all should be called first.
>
> Actually, looking a bit closer, what prevents the migration thread from
> starting new requests even after bdrv_drain_all()? Maybe what we really
> need to do is cancelling the migration before calling bdrv_close_all().

I was wondering *where* to put this call inside the migration cleanup
code, but I got to the conclusion that I was not sure that the migration
cancellation code got called when you just do a "quit".

Later, Juan.

Re: [Qemu-block] [PATCH] block: Cleanup BMDS in bdrv_close_all

2017-09-05 Thread Kevin Wolf 
Am 30.08.2017 um 12:06 hat Fam Zheng geschrieben:
> This fixes the assertion due to op blockers added by BMDS:
> 
> block.c:3248: bdrv_delete: Assertion `bdrv_op_blocker_is_empty(bs)' failed.
> 
> Reproducer: simply start block migration and quit QEMU before it ends.
> 
> Cc: qemu-sta...@nongnu.org
> Signed-off-by: Fam Zheng 
> ---
>  block.c | 2 ++
>  migration/block.c   | 2 +-
>  migration/block.h   | 1 +
>  stubs/Makefile.objs | 1 +
>  stubs/block-migration.c | 6 ++
>  5 files changed, 11 insertions(+), 1 deletion(-)
>  create mode 100644 stubs/block-migration.c
> 
> diff --git a/block.c b/block.c
> index 3308814bba..508a57274d 100644
> --- a/block.c
> +++ b/block.c
> @@ -43,6 +43,7 @@
>  #include "qemu/cutils.h"
>  #include "qemu/id.h"
>  #include "qapi/util.h"
> +#include "migration/block.h"
>  
>  #ifdef CONFIG_BSD
>  #include 
> @@ -3111,6 +3112,7 @@ static void bdrv_close(BlockDriverState *bs)
>  
>  void bdrv_close_all(void)
>  {
> +block_migration_cleanup_bmds();
>  block_job_cancel_sync_all();
>  nbd_export_close_all();

This is before bdrv_drain_all(). Can't we still have a block migration
request in flight, whose callback will then dereference a stale pointer?

Kevin

Re: [Qemu-block] [PATCH] block: Cleanup BMDS in bdrv_close_all

2017-09-04 Thread Fam Zheng 
On Fri, 09/01 13:41, Juan Quintela wrote:
> Fam Zheng  wrote:
> > This fixes the assertion due to op blockers added by BMDS:
> >
> > block.c:3248: bdrv_delete: Assertion `bdrv_op_blocker_is_empty(bs)' failed.
> >
> > Reproducer: simply start block migration and quit QEMU before it ends.
> >
> > Cc: qemu-sta...@nongnu.org
> > Signed-off-by: Fam Zheng 
> 
> Reviewed-by: Juan Quintela 
> 
> This stub stuff is crazy.
> 
> Fam, you were right (a.k.a. I was wrong).
> 
> Sorry, Juan.

Stefan, will you merge this?

Fam

Re: [Qemu-block] [PATCH] block: Cleanup BMDS in bdrv_close_all

2017-09-01 Thread Juan Quintela 
Fam Zheng  wrote:
> This fixes the assertion due to op blockers added by BMDS:
>
> block.c:3248: bdrv_delete: Assertion `bdrv_op_blocker_is_empty(bs)' failed.
>
> Reproducer: simply start block migration and quit QEMU before it ends.
>
> Cc: qemu-sta...@nongnu.org
> Signed-off-by: Fam Zheng 

Reviewed-by: Juan Quintela 

This stub stuff is crazy.

Fam, you were right (a.k.a. I was wrong).

Sorry, Juan.

Re: [Qemu-block] [PATCH] block: Cleanup BMDS in bdrv_close_all

2017-08-30 Thread Juan Quintela 
Fam Zheng  wrote:
> On Wed, 08/30 13:49, Juan Quintela wrote:
>> Fam Zheng  wrote:
>> > This fixes the assertion due to op blockers added by BMDS:
>> >
>> > block.c:3248: bdrv_delete: Assertion `bdrv_op_blocker_is_empty(bs)' failed.
>> >
>> > Reproducer: simply start block migration and quit QEMU before it ends.
>> >
>> > Cc: qemu-sta...@nongnu.org
>> > Signed-off-by: Fam Zheng 
>> 
>> No need for one stub, see later.
>> 
>> 
>> > ---
>> >  block.c | 2 ++
>> >  migration/block.c   | 2 +-
>> >  migration/block.h   | 1 +
>> >  stubs/Makefile.objs | 1 +
>> >  stubs/block-migration.c | 6 ++
>> >  5 files changed, 11 insertions(+), 1 deletion(-)
>> >  create mode 100644 stubs/block-migration.c
>> >
>> > diff --git a/block.c b/block.c
>> > index 3308814bba..508a57274d 100644
>> > --- a/block.c
>> > +++ b/block.c
>> > @@ -43,6 +43,7 @@
>> >  #include "qemu/cutils.h"
>> >  #include "qemu/id.h"
>> >  #include "qapi/util.h"
>> > +#include "migration/block.h"
>> 
>> this should be misc.h
>> 
>> >  
>> >  #ifdef CONFIG_BSD
>> >  #include 
>> > @@ -3111,6 +3112,7 @@ static void bdrv_close(BlockDriverState *bs)
>> >  
>> >  void bdrv_close_all(void)
>> >  {
>> > +block_migration_cleanup_bmds();
>> >  block_job_cancel_sync_all();
>> >  nbd_export_close_all();
>> >  
>> 
>> > diff --git a/migration/block.h b/migration/block.h
>> > index 22ebe94259..8bae1cf55a 100644
>> > --- a/migration/block.h
>> > +++ b/migration/block.h
>> > @@ -42,4 +42,5 @@ static inline uint64_t blk_mig_bytes_total(void)
>> >  #endif /* CONFIG_LIVE_BLOCK_MIGRATION */
>> >  
>> >  void migrate_set_block_enabled(bool value, Error **errp);
>> > +void block_migration_cleanup_bmds(void);
>> >  #endif /* MIGRATION_BLOCK_H */
>> > diff --git a/stubs/Makefile.objs b/stubs/Makefile.objs
>> > index e69c217aff..7540913767 100644
>> > --- a/stubs/Makefile.objs
>> > +++ b/stubs/Makefile.objs
>> > @@ -19,6 +19,7 @@ stub-obj-y += is-daemonized.o
>> >  stub-obj-$(CONFIG_LINUX_AIO) += linux-aio.o
>> >  stub-obj-y += machine-init-done.o
>> >  stub-obj-y += migr-blocker.o
>> > +stub-obj-y += block-migration.o
>> >  stub-obj-y += change-state-handler.o
>> >  stub-obj-y += monitor.o
>> >  stub-obj-y += notify-event.o
>> > diff --git a/stubs/block-migration.c b/stubs/block-migration.c
>> > new file mode 100644
>> > index 00..855f15c757
>> > --- /dev/null
>> > +++ b/stubs/block-migration.c
>> > @@ -0,0 +1,6 @@
>> > +#include "qemu/osdep.h"
>> > +#include "migration/block.h"
>> > +
>> > +void block_migration_cleanup_bmds(void)
>> > +{
>> > +}
>> 
>> You can add this inside include/migration/misc.h
>> 
>> #ifdef CONFIG_LIVE_BLOCK_MIGRATION
>> void blk_mig_init(void);
>> #else
>> static inline void blk_mig_init(void) {}
>> 
>> // And then you add the stub here?
>
> This doesn't work.  The function is not stubbed for 
> !CONFIG_LIVE_BLOCK_MIGRATION
> configs, but for tools that don't link to common-obj-y. For example with your
> proposed change, I get:
>
>   LINKqemu-nbd
> block.o: In function `bdrv_close_all':
> /home/fam/work/qemu/block.c:3115: undefined reference to
> `block_migration_cleanup_bmds'
> collect2: error: ld returned 1 exit status
> make: *** [/home/fam/work/qemu/rules.mak:121: qemu-nbd] Error 1
> make: Leaving directory '/home/fam/work/q/build'


This works for me, for both CONFIG_LIVE_BLOCK_MIGRATION enabled and not.
For qemu-system-x86_64 and qemu-nbd.  Could you test?

gcommit 2888b96dfe5ea9c7901990f54e14b1a7ed3e46b9
Author: Fam Zheng 
Date:   Wed Aug 30 18:06:05 2017 +0800

block: Cleanup BMDS in bdrv_close_all

This fixes the assertion due to op blockers added by BMDS:

block.c:3248: bdrv_delete: Assertion `bdrv_op_blocker_is_empty(bs)' failed.

Reproducer: simply start block migration and quit QEMU before it ends.

Cc: qemu-sta...@nongnu.org
Signed-off-by: Fam Zheng 

--

Don't use stub

diff --git a/block.c b/block.c
index 3615a6809e..4268f892da 100644
--- a/block.c
+++ b/block.c
@@ -43,6 +43,7 @@
 #include "qemu/cutils.h"
 #include "qemu/id.h"
 #include "qapi/util.h"
+#include "migration/misc.h"
 
 #ifdef CONFIG_BSD
 #include 
@@ -3111,6 +3112,7 @@ static void bdrv_close(BlockDriverState *bs)
 
 void bdrv_close_all(void)
 {
+block_migration_cleanup_bmds();
 block_job_cancel_sync_all();
 nbd_export_close_all();
 
diff --git a/include/migration/misc.h b/include/migration/misc.h
index c079b7771b..6ecb7068d9 100644
--- a/include/migration/misc.h
+++ b/include/migration/misc.h
@@ -24,8 +24,10 @@ void ram_mig_init(void);
 
 #ifdef CONFIG_LIVE_BLOCK_MIGRATION
 void blk_mig_init(void);
+void block_migration_cleanup_bmds(void);
 #else
 static inline void blk_mig_init(void) {}
+static inline void block_migration_cleanup_bmds(void) {}
 #endif
 
 #define SELF_ANNOUNCE_ROUNDS 5
diff --git a/migration/block.c b/migration/block.c
index 9171f60028..c059e48484

Re: [Qemu-block] [PATCH] block: Cleanup BMDS in bdrv_close_all

2017-08-30 Thread Juan Quintela 
Fam Zheng  wrote:
> This fixes the assertion due to op blockers added by BMDS:
>
> block.c:3248: bdrv_delete: Assertion `bdrv_op_blocker_is_empty(bs)' failed.
>
> Reproducer: simply start block migration and quit QEMU before it ends.
>
> Cc: qemu-sta...@nongnu.org
> Signed-off-by: Fam Zheng 

No need for one stub, see later.


> ---
>  block.c | 2 ++
>  migration/block.c   | 2 +-
>  migration/block.h   | 1 +
>  stubs/Makefile.objs | 1 +
>  stubs/block-migration.c | 6 ++
>  5 files changed, 11 insertions(+), 1 deletion(-)
>  create mode 100644 stubs/block-migration.c
>
> diff --git a/block.c b/block.c
> index 3308814bba..508a57274d 100644
> --- a/block.c
> +++ b/block.c
> @@ -43,6 +43,7 @@
>  #include "qemu/cutils.h"
>  #include "qemu/id.h"
>  #include "qapi/util.h"
> +#include "migration/block.h"

this should be misc.h

>  
>  #ifdef CONFIG_BSD
>  #include 
> @@ -3111,6 +3112,7 @@ static void bdrv_close(BlockDriverState *bs)
>  
>  void bdrv_close_all(void)
>  {
> +block_migration_cleanup_bmds();
>  block_job_cancel_sync_all();
>  nbd_export_close_all();
>  

> diff --git a/migration/block.h b/migration/block.h
> index 22ebe94259..8bae1cf55a 100644
> --- a/migration/block.h
> +++ b/migration/block.h
> @@ -42,4 +42,5 @@ static inline uint64_t blk_mig_bytes_total(void)
>  #endif /* CONFIG_LIVE_BLOCK_MIGRATION */
>  
>  void migrate_set_block_enabled(bool value, Error **errp);
> +void block_migration_cleanup_bmds(void);
>  #endif /* MIGRATION_BLOCK_H */
> diff --git a/stubs/Makefile.objs b/stubs/Makefile.objs
> index e69c217aff..7540913767 100644
> --- a/stubs/Makefile.objs
> +++ b/stubs/Makefile.objs
> @@ -19,6 +19,7 @@ stub-obj-y += is-daemonized.o
>  stub-obj-$(CONFIG_LINUX_AIO) += linux-aio.o
>  stub-obj-y += machine-init-done.o
>  stub-obj-y += migr-blocker.o
> +stub-obj-y += block-migration.o
>  stub-obj-y += change-state-handler.o
>  stub-obj-y += monitor.o
>  stub-obj-y += notify-event.o
> diff --git a/stubs/block-migration.c b/stubs/block-migration.c
> new file mode 100644
> index 00..855f15c757
> --- /dev/null
> +++ b/stubs/block-migration.c
> @@ -0,0 +1,6 @@
> +#include "qemu/osdep.h"
> +#include "migration/block.h"
> +
> +void block_migration_cleanup_bmds(void)
> +{
> +}

You can add this inside include/migration/misc.h

#ifdef CONFIG_LIVE_BLOCK_MIGRATION
void blk_mig_init(void);
#else
static inline void blk_mig_init(void) {}

// And then you add the stub here?

#endif


Once here, I would consider to give one error/warning if we quit qemu
and we are in the middle of a block migration, no?

Thanks, Juan.

[Qemu-block] [PATCH] block: Cleanup BMDS in bdrv_close_all

2017-08-30 Thread Fam Zheng 
This fixes the assertion due to op blockers added by BMDS:

block.c:3248: bdrv_delete: Assertion `bdrv_op_blocker_is_empty(bs)' failed.

Reproducer: simply start block migration and quit QEMU before it ends.

Cc: qemu-sta...@nongnu.org
Signed-off-by: Fam Zheng 
---
 block.c | 2 ++
 migration/block.c   | 2 +-
 migration/block.h   | 1 +
 stubs/Makefile.objs | 1 +
 stubs/block-migration.c | 6 ++
 5 files changed, 11 insertions(+), 1 deletion(-)
 create mode 100644 stubs/block-migration.c

diff --git a/block.c b/block.c
index 3308814bba..508a57274d 100644
--- a/block.c
+++ b/block.c
@@ -43,6 +43,7 @@
 #include "qemu/cutils.h"
 #include "qemu/id.h"
 #include "qapi/util.h"
+#include "migration/block.h"
 
 #ifdef CONFIG_BSD
 #include 
@@ -3111,6 +3112,7 @@ static void bdrv_close(BlockDriverState *bs)
 
 void bdrv_close_all(void)
 {
+block_migration_cleanup_bmds();
 block_job_cancel_sync_all();
 nbd_export_close_all();
 
diff --git a/migration/block.c b/migration/block.c
index 9171f60028..c059e48484 100644
--- a/migration/block.c
+++ b/migration/block.c
@@ -673,7 +673,7 @@ static int64_t get_remaining_dirty(void)
 
 
 /* Called with iothread lock taken.  */
-static void block_migration_cleanup_bmds(void)
+void block_migration_cleanup_bmds(void)
 {
 BlkMigDevState *bmds;
 AioContext *ctx;
diff --git a/migration/block.h b/migration/block.h
index 22ebe94259..8bae1cf55a 100644
--- a/migration/block.h
+++ b/migration/block.h
@@ -42,4 +42,5 @@ static inline uint64_t blk_mig_bytes_total(void)
 #endif /* CONFIG_LIVE_BLOCK_MIGRATION */
 
 void migrate_set_block_enabled(bool value, Error **errp);
+void block_migration_cleanup_bmds(void);
 #endif /* MIGRATION_BLOCK_H */
diff --git a/stubs/Makefile.objs b/stubs/Makefile.objs
index e69c217aff..7540913767 100644
--- a/stubs/Makefile.objs
+++ b/stubs/Makefile.objs
@@ -19,6 +19,7 @@ stub-obj-y += is-daemonized.o
 stub-obj-$(CONFIG_LINUX_AIO) += linux-aio.o
 stub-obj-y += machine-init-done.o
 stub-obj-y += migr-blocker.o
+stub-obj-y += block-migration.o
 stub-obj-y += change-state-handler.o
 stub-obj-y += monitor.o
 stub-obj-y += notify-event.o
diff --git a/stubs/block-migration.c b/stubs/block-migration.c
new file mode 100644
index 00..855f15c757
--- /dev/null
+++ b/stubs/block-migration.c
@@ -0,0 +1,6 @@
+#include "qemu/osdep.h"
+#include "migration/block.h"
+
+void block_migration_cleanup_bmds(void)
+{
+}
-- 
2.13.5