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

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

[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-stable@nongnu.org
Signed-off-by: Fam Zheng <famz@redhat.com>
---
 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 <sys/ioctl.h>
@@ -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 0000000000..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

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

[Juan Quintela]

Fam Zheng <famz@redhat.com> 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-stable@nongnu.org
> Signed-off-by: Fam Zheng <famz@redhat.com>

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 <sys/ioctl.h>
> @@ -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 0000000000..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.

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

[Fam Zheng]

On Wed, 08/30 13:49, Juan Quintela wrote:
> Fam Zheng <famz@redhat.com> 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-stable@nongnu.org
> > Signed-off-by: Fam Zheng <famz@redhat.com>
> 
> 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 <sys/ioctl.h>
> > @@ -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 0000000000..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:

  LINK    qemu-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'

> 
> #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?

We already have various types of block jobs, such as mirror and backup, and even
non-block tasks like migration and dump that runs in the background. None gives
error/warning.  Keeping quiet here is consistent with other code.

Fam

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

[Juan Quintela]

Fam Zheng <famz@redhat.com> wrote:
> On Wed, 08/30 13:49, Juan Quintela wrote:
>> Fam Zheng <famz@redhat.com> 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-stable@nongnu.org
>> > Signed-off-by: Fam Zheng <famz@redhat.com>
>> 
>> 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 <sys/ioctl.h>
>> > @@ -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 0000000000..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:
>
>   LINK    qemu-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 <famz@redhat.com>
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-stable@nongnu.org
    Signed-off-by: Fam Zheng <famz@redhat.com>
    
    --
    
    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 <sys/ioctl.h>
@@ -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 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;

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

[Fam Zheng]

On Wed, 08/30 16:04, Juan Quintela wrote:
> Fam Zheng <famz@redhat.com> wrote:
> > On Wed, 08/30 13:49, Juan Quintela wrote:
> >> Fam Zheng <famz@redhat.com> 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-stable@nongnu.org
> >> > Signed-off-by: Fam Zheng <famz@redhat.com>
> >> 
> >> 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 <sys/ioctl.h>
> >> > @@ -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 0000000000..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:
> >
> >   LINK    qemu-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?

I get the same error:

  LINK    qemu-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'

(also applies to qemu-img etc.)

Fam

---

$ cat config.status 
#!/bin/sh
# Generated by configure.
# Run this file to recreate the current configuration.
# Compiler output produced by configure, useful for debugging
# configure, is in config.log if it exists.
exec '/home/fam/work/qemu/configure' '--prefix=/home/fam/work/q/install/bdrv_close_all-bmds' '--enable-debug' '--extra-cflags=-Wno-error=format-truncation' '--target-list=x86_64-softmmu' "$@"

$ grep CONFIG_LIVE_BLOCK_MIGRATION config-host.h
#define CONFIG_LIVE_BLOCK_MIGRATION 1

$ make qemu-nbd V=1
(cd /home/fam/work/qemu; printf '#define QEMU_PKGVERSION '; if test -n ""; then printf '""\n'; else if test -d .git; then printf '" ('; git describe --match 'v*' 2>/dev/null | tr -d '\n'; if ! git diff-index --quiet HEAD &>/dev/null; then printf -- '-dirty'; fi; printf ')"\n'; else printf '""\n'; fi; fi) > qemu-version.h.tmp
if ! cmp -s qemu-version.h qemu-version.h.tmp; then mv qemu-version.h.tmp qemu-version.h; else rm qemu-version.h.tmp; fi
c++ -I/usr/include/pixman-1   -Werror -DHAS_LIBSSH2_SFTP_FSYNC -pthread -I/usr/include/glib-2.0 -I/usr/lib64/glib-2.0/include  -DNCURSES_WIDECHAR -D_GNU_SOURCE -D_DEFAULT_SOURCE  -fPIE -DPIE -m64 -mcx16 -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -Wstrict-prototypes -Wredundant-decls -Wall -Wundef -Wwrite-strings -Wmissing-prototypes -fno-strict-aliasing -fno-common -fwrapv  -Wno-error=format-truncation -Wexpansion-to-defined -Wendif-labels -Wno-shift-negative-value -Wno-missing-include-dirs -Wempty-body -Wnested-externs -Wformat-security -Wformat-y2k -Winit-self -Wignored-qualifiers -Wold-style-declaration -Wold-style-definition -Wtype-limits -fstack-protector-strong  -I/usr/include/p11-kit-1    -I/usr/include/libpng16  -I/usr/include/spice-1 -I/usr/include/spice-server -I/usr/include/cacard -I/usr/include/glib-2.0 -I/usr/lib64/glib-2.0/include -I/usr/include/nss3 -I/usr/include/nspr4 -pthread -I/usr/include/pixman-1  -I/usr/include/cacard -I/usr/include/glib-2.0 -I/usr/lib64/glib-2.0/include -I/usr/include/nss3 -I/usr/include/nspr4  -I/usr/include/libusb-1.0   -I/home/fam/work/qemu/tests -g  -Wl,--warn-common -Wl,-z,relro -Wl,-z,now -pie -m64 -g  -o qemu-nbd qemu-nbd.o block.o blockjob.o qemu-io-cmds.o replication.o block/raw-format.o block/qcow.o block/vdi.o block/vmdk.o block/cloop.o block/bochs.o block/vpc.o block/vvfat.o block/dmg.o block/qcow2.o block/qcow2-refcount.o block/qcow2-cluster.o block/qcow2-snapshot.o block/qcow2-cache.o block/qcow2-bitmap.o block/qed.o block/qed-l2-cache.o block/qed-table.o block/qed-cluster.o block/qed-check.o block/vhdx.o block/vhdx-endian.o block/vhdx-log.o block/quorum.o block/parallels.o block/blkdebug.o block/blkverify.o block/blkreplay.o block/block-backend.o block/snapshot.o block/qapi.o block/file-posix.o block/linux-aio.o block/null.o block/mirror.o block/commit.o block/io.o block/throttle-groups.o block/nbd.o block/nbd-client.o block/sheepdog.o block/iscsi-opts.o block/accounting.o block/dirty-bitmap.o block/write-threshold.o block/backup.o block/replication.o block/crypto.o nbd/server.o nbd/client.o nbd/common.o block/iscsi.o block/curl.o block/rbd.o block/gluster.o block/ssh.o block/dmg-bz2.o crypto/init.o crypto/hash.o crypto/hash-nettle.o crypto/hmac.o crypto/hmac-nettle.o crypto/aes.o crypto/desrfb.o crypto/cipher.o crypto/tlscreds.o crypto/tlscredsanon.o crypto/tlscredsx509.o crypto/tlssession.o crypto/secret.o crypto/random-gnutls.o crypto/pbkdf.o crypto/pbkdf-nettle.o crypto/ivgen.o crypto/ivgen-essiv.o crypto/ivgen-plain.o crypto/ivgen-plain64.o crypto/afsplit.o crypto/xts.o crypto/block.o crypto/block-qcow.o crypto/block-luks.o io/channel.o io/channel-buffer.o io/channel-command.o io/channel-file.o io/channel-socket.o io/channel-tls.o io/channel-watch.o io/channel-websock.o io/channel-util.o io/dns-resolver.o io/task.o qom/object.o qom/container.o qom/qom-qobject.o qom/object_interfaces.o  libqemuutil.a libqemustub.a  -lz -laio -L/usr/lib64/iscsi -liscsi -lcurl -lrbd -lrados -lacl -lgfapi -lglusterfs -lgfrpc -lgfxdr -luuid -lssh2 -lbz2 -lm -lgthread-2.0 -pthread -lglib-2.0   -lz -lrt -lz -lnettle  -lgnutls   -lutil

$ nm migration/block.o | grep block_migration_cleanup_bmds
00000000000011e8 T block_migration_cleanup_bmds


> 
> gcommit 2888b96dfe5ea9c7901990f54e14b1a7ed3e46b9
> Author: Fam Zheng <famz@redhat.com>
> 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-stable@nongnu.org
>     Signed-off-by: Fam Zheng <famz@redhat.com>
>     
>     --
>     
>     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 <sys/ioctl.h>
> @@ -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 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;
> 
> 

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

[Juan Quintela]

Fam Zheng <famz@redhat.com> 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-stable@nongnu.org
> Signed-off-by: Fam Zheng <famz@redhat.com>

Reviewed-by: Juan Quintela <quintela@redhat.com>

This stub stuff is crazy.

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

Sorry, Juan.

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

[Fam Zheng]

On Fri, 09/01 13:41, Juan Quintela wrote:
> Fam Zheng <famz@redhat.com> 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-stable@nongnu.org
> > Signed-off-by: Fam Zheng <famz@redhat.com>
> 
> Reviewed-by: Juan Quintela <quintela@redhat.com>
> 
> 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-devel] [PATCH] block: Cleanup BMDS in bdrv_close_all

[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-stable@nongnu.org
> Signed-off-by: Fam Zheng <famz@redhat.com>
> ---
>  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 <sys/ioctl.h>
> @@ -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-devel] [PATCH] block: Cleanup BMDS in bdrv_close_all

[Fam Zheng]

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-stable@nongnu.org
> > Signed-off-by: Fam Zheng <famz@redhat.com>
> > ---
> >  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 <sys/ioctl.h>
> > @@ -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.

Fam

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

[Kevin Wolf]

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-stable@nongnu.org
> > > Signed-off-by: Fam Zheng <famz@redhat.com>
> > > ---
> > >  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 <sys/ioctl.h>
> > > @@ -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().

Kevin

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

[Juan Quintela]

Kevin Wolf <kwolf@redhat.com> 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-stable@nongnu.org
>> > > Signed-off-by: Fam Zheng <famz@redhat.com>
>> > > ---
>> > >  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 <sys/ioctl.h>
>> > > @@ -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-devel] [Qemu-block] [PATCH] block: Cleanup BMDS in bdrv_close_all

[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-stable@nongnu.org
> Signed-off-by: Fam Zheng <famz@redhat.com>
> ---
>  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-devel] [Qemu-block] [PATCH] block: Cleanup BMDS in bdrv_close_all

[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-stable@nongnu.org
> > Signed-off-by: Fam Zheng <famz@redhat.com>
> > ---
> >  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