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fix bitmaps migration through shared storage

PATCH Superseded Vladimir Sementsov-Ogievskiy 2 participants 13 messages Dec 12, 2017 – Jan 10, 2018 Block layer

v2 of 4 Superseded Latest is v4 →

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Vladimir Sementsov-Ogievskiy

author
#0 lore raw

v2 cover fix bitmaps migration through shared storage

Hi all.

This fixes bitmaps migration through shared storage. Look at 02 for details.

The bug introduced in 2.10 with the whole qcow2 bitmaps feature, so qemu-stable in CC. However I doubt that someone really suffered from this.

v2:
John, thank you for reviewing v1.
changes:
add John's r-bs, change s/timeout=10/timeout=10.0/ in last patch and drop old 03 patch, related to this timeout fix.

Vladimir Sementsov-Ogievskiy (3):
qcow2-bitmap: add qcow2_reopen_bitmaps_rw_hint()
qcow2: handle reopening bitmaps on bdrv_invalidate_cache
iotests: add dirty bitmap migration test

 block/qcow2.h              |  2 ++
 block/qcow2-bitmap.c       | 15 ++++++++-
 block/qcow2.c              |  8 ++++-
 tests/qemu-iotests/169     | 82 ++++++++++++++++++++++++++++++++++++++++++++++
 tests/qemu-iotests/169.out |  5 +++
 tests/qemu-iotests/group   |  1 +
 6 files changed, 111 insertions(+), 2 deletions(-)
 create mode 100755 tests/qemu-iotests/169
 create mode 100644 tests/qemu-iotests/169.out
Signature · 1 line
2.11.1
author
#1 lore raw

PATCH v2 1/3 qcow2-bitmap: add qcow2_reopen_bitmaps_rw_hint()

Add version of qcow2_reopen_bitmaps_rw, which do the same work but also return a hint about was header updated or not. This will be used in the following fix for bitmaps reloading after migration.

Signed-off-by Vladimir Sementsov-Ogievskiy <[email protected]>
Reviewed-by John Snow <[email protected]>
---
 block/qcow2.h        |  2 ++
 block/qcow2-bitmap.c | 15 ++++++++++++++-
 2 files changed, 16 insertions(+), 1 deletion(-)
block/qcow2.h +2 -0
index 6f0ff15dd0..40fa5b7cfe 100644
@@ -667,6 +667,8 @@ int qcow2_check_bitmaps_refcounts(BlockDriverState *bs, BdrvCheckResult *res,
                                   void **refcount_table,
                                   int64_t *refcount_table_size);
 bool qcow2_load_autoloading_dirty_bitmaps(BlockDriverState *bs, Error **errp);
+int qcow2_reopen_bitmaps_rw_hint(BlockDriverState *bs, bool *header_updated,
+                                 Error **errp);
 int qcow2_reopen_bitmaps_rw(BlockDriverState *bs, Error **errp);
 void qcow2_store_persistent_dirty_bitmaps(BlockDriverState *bs, Error **errp);
 int qcow2_reopen_bitmaps_ro(BlockDriverState *bs, Error **errp);
block/qcow2-bitmap.c +14 -1
index f45e46cfbd..6c80dcda69 100644
@@ -1002,7 +1002,8 @@ fail:
     return false;
 }
 
-int qcow2_reopen_bitmaps_rw(BlockDriverState *bs, Error **errp)
+int qcow2_reopen_bitmaps_rw_hint(BlockDriverState *bs, bool *header_updated,
+                                 Error **errp)
 {
     BDRVQcow2State *s = bs->opaque;
     Qcow2BitmapList *bm_list;

@@ -1010,6 +1011,10 @@ int qcow2_reopen_bitmaps_rw(BlockDriverState *bs, Error **errp)
     GSList *ro_dirty_bitmaps = NULL;
     int ret = 0;
 
+    if (header_updated != NULL) {
+        *header_updated = false;
+    }
+
     if (s->nb_bitmaps == 0) {
         /* No bitmaps - nothing to do */
         return 0;

@@ -1053,6 +1058,9 @@ int qcow2_reopen_bitmaps_rw(BlockDriverState *bs, Error **errp)
             error_setg_errno(errp, -ret, "Can't update bitmap directory");
             goto out;
         }
+        if (header_updated != NULL) {
+            *header_updated = true;
+        }
         g_slist_foreach(ro_dirty_bitmaps, set_readonly_helper, false);
     }
 

@@ -1063,6 +1071,11 @@ out:
     return ret;
 }
 
+int qcow2_reopen_bitmaps_rw(BlockDriverState *bs, Error **errp)
+{
+    return qcow2_reopen_bitmaps_rw_hint(bs, NULL, errp);
+}
+
 /* store_bitmap_data()
  * Store bitmap to image, filling bitmap table accordingly.
  */
Signature · 1 line
2.11.1
author
#2 lore raw

PATCH v2 2/3 qcow2: handle reopening bitmaps on bdrv_invalidate_cache

In reply to Vladimir Sementsov-Ogievskiy

Consider migration with shared storage. Persistent bitmaps are stored on bdrv_inactivate. Then, on destination process_incoming_migration_bh() calls bdrv_invalidate_cache_all() which leads to qcow2_load_autoloading_dirty_bitmaps() which fails if bitmaps are already loaded on destination start. In this case we should call qcow2_reopen_bitmaps_rw instead.

Signed-off-by Vladimir Sementsov-Ogievskiy <[email protected]>
Reviewed-by John Snow <[email protected]>
---
 block/qcow2.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)
block/qcow2.c +7 -1
index 1914a940e5..f5f205e1b7 100644
@@ -1450,7 +1450,13 @@ static int qcow2_do_open(BlockDriverState *bs, QDict *options, int flags,
         s->autoclear_features &= QCOW2_AUTOCLEAR_MASK;
     }
 
-    if (qcow2_load_autoloading_dirty_bitmaps(bs, &local_err)) {
+    if (bdrv_has_readonly_bitmaps(bs)) {
+        if (!bdrv_is_read_only(bs) && !(bdrv_get_flags(bs) & BDRV_O_INACTIVE)) {
+            bool header_updated = false;
+            qcow2_reopen_bitmaps_rw_hint(bs, &header_updated, &local_err);
+            update_header = update_header && !header_updated;
+        }
+    } else if (qcow2_load_autoloading_dirty_bitmaps(bs, &local_err)) {
         update_header = false;
     }
     if (local_err != NULL) {
Signature · 1 line
2.11.1
#3 lore raw

Re: [Qemu-devel] [PATCH v2 2/3] qcow2: handle reopening bitmaps on bdrv_invalidate_cache

Am 12.12.2017 um 17:04 hat Vladimir Sementsov-Ogievskiy geschrieben:

Quoted 9 lines

Consider migration with shared storage. Persistent bitmaps are stored on bdrv_inactivate. Then, on destination process_incoming_migration_bh() calls bdrv_invalidate_cache_all() which leads to qcow2_load_autoloading_dirty_bitmaps() which fails if bitmaps are already loaded on destination start. In this case we should call qcow2_reopen_bitmaps_rw instead.

Signed-off-by Vladimir Sementsov-Ogievskiy <[email protected]>
Reviewed-by John Snow <[email protected]>

qcow2_invalidate_cache() calls qcow2_close() first, so why are there still any bitmaps loaded? Isn't this a bug? Do we leak bitmaps when a qcow2 image is closed?

Kevin

author
#4 lore raw

Re: [Qemu-devel] [PATCH v2 2/3] qcow2: handle reopening bitmaps on bdrv_invalidate_cache

Quoted 8 lines · Kevin Wolf

Am 12.12.2017 um 17:04 hat Vladimir Sementsov-Ogievskiy geschrieben:

Quoted 7 lines

Consider migration with shared storage. Persistent bitmaps are stored on bdrv_inactivate. Then, on destination process_incoming_migration_bh() calls bdrv_invalidate_cache_all() which leads to qcow2_load_autoloading_dirty_bitmaps() which fails if bitmaps are already loaded on destination start. In this case we should call qcow2_reopen_bitmaps_rw instead.

Quoted 7 lines
Quoted 2 lines
Signed-off-by Vladimir Sementsov-Ogievskiy <[email protected]>
Reviewed-by John Snow <[email protected]>

qcow2_invalidate_cache() calls qcow2_close() first, so why are there still any bitmaps loaded? Isn't this a bug? Do we leak bitmaps when a qcow2 image is closed?

Kevin

Interesting point.

Now persistent dirty bitmaps are released at the end of bdrv_inactivate_recurse, which is not called here. It was a separate patch

commit 615b5dcf2decbc5f0abb512d13d7e5db2385fa23
Author: Vladimir Sementsov-Ogievskiy <[email protected]> Date:   Wed Jun 28 15:05:30 2017 +0300

    block: release persistent bitmaps on inactivate

May be it is more correct to release them immediately after storing, in qcow2_inactivete. But it will not fix the issue, because qcow2_close will call qcow2_inactivate only if (!(s->flags & BDRV_O_INACTIVE)), but it is not the case.

or we can do like this, it fixes the new test:
  static void qcow2_close(BlockDriverState *bs)
{
      BDRVQcow2State *s = bs->opaque; qemu_vfree(s->l1_table);
      /* else pre-write overlap checks in cache_destroy may crash */ s->l1_table = NULL;

      if (!(s->flags & BDRV_O_INACTIVE)) {
qcow2_inactivate(bs);
}
+     bdrv_release_persistent_dirty_bitmaps(bs);

What do you think?

Signature · 2 lines
Best regards,
Vladimir
#5 lore raw

Re: [Qemu-devel] [PATCH v2 2/3] qcow2: handle reopening bitmaps on bdrv_invalidate_cache

Am 22.12.2017 um 15:25 hat Vladimir Sementsov-Ogievskiy geschrieben:

Quoted 23 lines
Quoted 8 lines · Kevin Wolf

Am 12.12.2017 um 17:04 hat Vladimir Sementsov-Ogievskiy geschrieben:

Quoted 7 lines

Consider migration with shared storage. Persistent bitmaps are stored on bdrv_inactivate. Then, on destination process_incoming_migration_bh() calls bdrv_invalidate_cache_all() which leads to qcow2_load_autoloading_dirty_bitmaps() which fails if bitmaps are already loaded on destination start. In this case we should call qcow2_reopen_bitmaps_rw instead.

Quoted 7 lines
Quoted 2 lines
Signed-off-by Vladimir Sementsov-Ogievskiy <[email protected]>
Reviewed-by John Snow <[email protected]>

qcow2_invalidate_cache() calls qcow2_close() first, so why are there still any bitmaps loaded? Isn't this a bug? Do we leak bitmaps when a qcow2 image is closed?

Kevin

Interesting point.

Now persistent dirty bitmaps are released at the end of bdrv_inactivate_recurse,
which is not called here. It was a separate patch

Quoted 8 lines

commit 615b5dcf2decbc5f0abb512d13d7e5db2385fa23
Author: Vladimir Sementsov-Ogievskiy <[email protected]> Date:   Wed Jun 28 15:05:30 2017 +0300

    block: release persistent bitmaps on inactivate

May be it is more correct to release them immediately after storing, in qcow2_inactivete.

I chose the question form because I'm really not deep enough into the bitmap code to have a solid opinion, but I have a feeling that releasing the bitmaps from the block driver that provided them would be cleaner indeed. I suppose the same is true for .bdrv_close.

Quoted 3 lines

But it will not fix the issue, because qcow2_close will
call qcow2_inactivate only if (!(s->flags & BDRV_O_INACTIVE)), but it is not the case.

Yes, good point.

Is there a reason why bitmaps are already loaded in qcow2_do_open() even if the image is inactive? Can bitmaps be meaningfully used on inactive images?

Otherwise, we could just make qcow2_load_autoloading_dirty_bitmaps() conditional on cleared BDRV_O_INACTIVE.

Quoted 8 lines

or we can do like this, it fixes the new test:
  static void qcow2_close(BlockDriverState *bs)
{
      BDRVQcow2State *s = bs->opaque; qemu_vfree(s->l1_table);
      /* else pre-write overlap checks in cache_destroy may crash */ s->l1_table = NULL;

Quoted 6 lines

      if (!(s->flags & BDRV_O_INACTIVE)) {
qcow2_inactivate(bs);
}
+     bdrv_release_persistent_dirty_bitmaps(bs);

What do you think?

Hm, I think I don't like this much.

We just need to decide what the status of inactive images is supposed to be. If they should have bitmaps, then your patch is probably right. But if inactive images shouldn't have any, we need to change qcow2_do_open() and qcow2_inactivate().

Kevin

author
#6 lore raw

Re: [Qemu-devel] [PATCH v2 2/3] qcow2: handle reopening bitmaps on bdrv_invalidate_cache

Quoted 62 lines · Kevin Wolf

Am 22.12.2017 um 15:25 hat Vladimir Sementsov-Ogievskiy geschrieben:

Quoted 22 lines
Quoted 8 lines · Kevin Wolf

Am 12.12.2017 um 17:04 hat Vladimir Sementsov-Ogievskiy geschrieben:

Quoted 7 lines

Consider migration with shared storage. Persistent bitmaps are stored on bdrv_inactivate. Then, on destination process_incoming_migration_bh() calls bdrv_invalidate_cache_all() which leads to qcow2_load_autoloading_dirty_bitmaps() which fails if bitmaps are already loaded on destination start. In this case we should call qcow2_reopen_bitmaps_rw instead.

Quoted 7 lines
Quoted 2 lines
Signed-off-by Vladimir Sementsov-Ogievskiy <[email protected]>
Reviewed-by John Snow <[email protected]>

qcow2_invalidate_cache() calls qcow2_close() first, so why are there still any bitmaps loaded? Isn't this a bug? Do we leak bitmaps when a qcow2 image is closed?

Kevin

Interesting point.

Now persistent dirty bitmaps are released at the end of bdrv_inactivate_recurse,
which is not called here. It was a separate patch

Quoted 8 lines

commit 615b5dcf2decbc5f0abb512d13d7e5db2385fa23
Author: Vladimir Sementsov-Ogievskiy <[email protected]> Date:   Wed Jun 28 15:05:30 2017 +0300

    block: release persistent bitmaps on inactivate

May be it is more correct to release them immediately after storing, in qcow2_inactivete.

I chose the question form because I'm really not deep enough into the bitmap code to have a solid opinion, but I have a feeling that releasing the bitmaps from the block driver that provided them would be cleaner indeed. I suppose the same is true for .bdrv_close.

Quoted 3 lines

But it will not fix the issue, because qcow2_close will
call qcow2_inactivate only if (!(s->flags & BDRV_O_INACTIVE)), but it is not the case.

Yes, good point.

Is there a reason why bitmaps are already loaded in qcow2_do_open() even if the image is inactive? Can bitmaps be meaningfully used on inactive images?

Otherwise, we could just make qcow2_load_autoloading_dirty_bitmaps() conditional on cleared BDRV_O_INACTIVE.

Quoted 8 lines

or we can do like this, it fixes the new test:
  static void qcow2_close(BlockDriverState *bs)
{
      BDRVQcow2State *s = bs->opaque;
qemu_vfree(s->l1_table);
      /* else pre-write overlap checks in cache_destroy may crash */ s->l1_table = NULL;

Quoted 6 lines

      if (!(s->flags & BDRV_O_INACTIVE)) {
qcow2_inactivate(bs);
}
+     bdrv_release_persistent_dirty_bitmaps(bs);

What do you think?

Quoted 8 lines

Hm, I think I don't like this much.

We just need to decide what the status of inactive images is supposed to be. If they should have bitmaps, then your patch is probably right. But if inactive images shouldn't have any, we need to change qcow2_do_open() and qcow2_inactivate().

Kevin

Does Qemu start in inactive mode when and only when it is incoming migration? In this case I don't see any reason of early-load the bitmaps. Backup in inactive mode should not be allowed too, yes?

So, it looks like it's ok to just do not autoload bitmaps if we are in inactive mode. The difference would be that user will not see these bitmaps during migration. And he even may create bitmaps with same names, which will lead to fault. But it don't look like real problem.

So, if there will not be other thoughts, I'll make another patch.

Signature · 2 lines
Best regards,
Vladimir
#7 lore raw

Re: [Qemu-devel] [PATCH v2 2/3] qcow2: handle reopening bitmaps on bdrv_invalidate_cache

Am 22.12.2017 um 17:12 hat Vladimir Sementsov-Ogievskiy geschrieben:

Quoted 70 lines
Quoted 69 lines · Kevin Wolf

Am 22.12.2017 um 15:25 hat Vladimir Sementsov-Ogievskiy geschrieben:

Quoted 22 lines
Quoted 8 lines · Kevin Wolf

Am 12.12.2017 um 17:04 hat Vladimir Sementsov-Ogievskiy geschrieben:

Quoted 7 lines

Consider migration with shared storage. Persistent bitmaps are stored on bdrv_inactivate. Then, on destination process_incoming_migration_bh() calls bdrv_invalidate_cache_all() which leads to qcow2_load_autoloading_dirty_bitmaps() which fails if bitmaps are already loaded on destination start. In this case we should call qcow2_reopen_bitmaps_rw instead.

Quoted 7 lines
Quoted 2 lines
Signed-off-by Vladimir Sementsov-Ogievskiy <[email protected]>
Reviewed-by John Snow <[email protected]>

qcow2_invalidate_cache() calls qcow2_close() first, so why are there still any bitmaps loaded? Isn't this a bug? Do we leak bitmaps when a qcow2 image is closed?

Kevin

Interesting point.

Now persistent dirty bitmaps are released at the end of bdrv_inactivate_recurse,
which is not called here. It was a separate patch

Quoted 8 lines

commit 615b5dcf2decbc5f0abb512d13d7e5db2385fa23
Author: Vladimir Sementsov-Ogievskiy <[email protected]> Date:   Wed Jun 28 15:05:30 2017 +0300

    block: release persistent bitmaps on inactivate

May be it is more correct to release them immediately after storing, in qcow2_inactivete.

I chose the question form because I'm really not deep enough into the bitmap code to have a solid opinion, but I have a feeling that releasing the bitmaps from the block driver that provided them would be cleaner indeed. I suppose the same is true for .bdrv_close.

Quoted 3 lines

But it will not fix the issue, because qcow2_close will
call qcow2_inactivate only if (!(s->flags & BDRV_O_INACTIVE)), but it is not the case.

Yes, good point.

Is there a reason why bitmaps are already loaded in qcow2_do_open() even if the image is inactive? Can bitmaps be meaningfully used on inactive images?

Otherwise, we could just make qcow2_load_autoloading_dirty_bitmaps() conditional on cleared BDRV_O_INACTIVE.

Quoted 8 lines

or we can do like this, it fixes the new test:
  static void qcow2_close(BlockDriverState *bs)
{
      BDRVQcow2State *s = bs->opaque;
qemu_vfree(s->l1_table);
      /* else pre-write overlap checks in cache_destroy may crash */ s->l1_table = NULL;

Quoted 6 lines

      if (!(s->flags & BDRV_O_INACTIVE)) {
qcow2_inactivate(bs);
}
+     bdrv_release_persistent_dirty_bitmaps(bs);

What do you think?

Hm, I think I don't like this much.

We just need to decide what the status of inactive images is supposed to be. If they should have bitmaps, then your patch is probably right. But if inactive images shouldn't have any, we need to change qcow2_do_open() and qcow2_inactivate().

Quoted 5 lines
Quoted 1 line

Kevin

Does Qemu start in inactive mode when and only when it is incoming migration? In this case I don't see any reason of early-load the bitmaps. Backup in inactive mode should not be allowed too, yes?

Yes, inactive images are only for incoming migration at the moment.

I would like to change that into opening all images as inactive and then immediately activate them (just to unify two code paths, one of which isn't tested as much as it should be), but that wouldn't be visible externally, so it should be fine, too.

Quoted 4 lines

So, it looks like it's ok to just do not autoload bitmaps if we are in inactive mode. The difference would be that user will not see these bitmaps during migration. And he even may create bitmaps with same names, which will lead to fault. But it don't look like real problem.

You can't create persistent bitmaps on an inactive image anyway, because that would involve writes.

Conflicts with temporary bitmaps might be possible, though.

Kevin

author
#8 lore raw

Re: [Qemu-devel] [PATCH v2 2/3] qcow2: handle reopening bitmaps on bdrv_invalidate_cache

Quoted 75 lines · Kevin Wolf

Am 22.12.2017 um 17:12 hat Vladimir Sementsov-Ogievskiy geschrieben:

Quoted 70 lines
Quoted 69 lines · Kevin Wolf

Am 22.12.2017 um 15:25 hat Vladimir Sementsov-Ogievskiy geschrieben:

Quoted 22 lines
Quoted 8 lines · Kevin Wolf

Am 12.12.2017 um 17:04 hat Vladimir Sementsov-Ogievskiy geschrieben:

Quoted 7 lines

Consider migration with shared storage. Persistent bitmaps are stored on bdrv_inactivate. Then, on destination process_incoming_migration_bh() calls bdrv_invalidate_cache_all() which leads to qcow2_load_autoloading_dirty_bitmaps() which fails if bitmaps are already loaded on destination start. In this case we should call qcow2_reopen_bitmaps_rw instead.

Quoted 7 lines
Quoted 2 lines
Signed-off-by Vladimir Sementsov-Ogievskiy <[email protected]>
Reviewed-by John Snow <[email protected]>

qcow2_invalidate_cache() calls qcow2_close() first, so why are there still any bitmaps loaded? Isn't this a bug? Do we leak bitmaps when a qcow2 image is closed?

Kevin

Interesting point.

Now persistent dirty bitmaps are released at the end of bdrv_inactivate_recurse,
which is not called here. It was a separate patch

Quoted 8 lines

commit 615b5dcf2decbc5f0abb512d13d7e5db2385fa23
Author: Vladimir Sementsov-Ogievskiy <[email protected]> Date:   Wed Jun 28 15:05:30 2017 +0300

    block: release persistent bitmaps on inactivate

May be it is more correct to release them immediately after storing, in qcow2_inactivete.

I chose the question form because I'm really not deep enough into the bitmap code to have a solid opinion, but I have a feeling that releasing the bitmaps from the block driver that provided them would be cleaner indeed. I suppose the same is true for .bdrv_close.

Quoted 3 lines

But it will not fix the issue, because qcow2_close will
call qcow2_inactivate only if (!(s->flags & BDRV_O_INACTIVE)), but it is not the case.

Yes, good point.

Is there a reason why bitmaps are already loaded in qcow2_do_open() even if the image is inactive? Can bitmaps be meaningfully used on inactive images?

Otherwise, we could just make qcow2_load_autoloading_dirty_bitmaps() conditional on cleared BDRV_O_INACTIVE.

Quoted 8 lines

or we can do like this, it fixes the new test:
  static void qcow2_close(BlockDriverState *bs)
{
      BDRVQcow2State *s = bs->opaque;
qemu_vfree(s->l1_table);
      /* else pre-write overlap checks in cache_destroy may crash */ s->l1_table = NULL;

Quoted 6 lines

      if (!(s->flags & BDRV_O_INACTIVE)) {
qcow2_inactivate(bs);
}
+     bdrv_release_persistent_dirty_bitmaps(bs);

What do you think?

Hm, I think I don't like this much.

We just need to decide what the status of inactive images is supposed to be. If they should have bitmaps, then your patch is probably right. But if inactive images shouldn't have any, we need to change qcow2_do_open() and qcow2_inactivate().

Quoted 4 lines
Quoted 1 line

Kevin

Does Qemu start in inactive mode when and only when it is incoming migration? In this case I don't see any reason of early-load the bitmaps. Backup in inactive mode should not be allowed too, yes?

Quoted 6 lines

Yes, inactive images are only for incoming migration at the moment.

I would like to change that into opening all images as inactive and then immediately activate them (just to unify two code paths, one of which isn't tested as much as it should be), but that wouldn't be visible externally, so it should be fine, too.

similar approach led to a problem for us:

To make it possible to modify drives through nbd before start (a kind of external reatore), I've added simple @@ -4727,6 +4727,8 @@ int main(int argc, char **argv, char **envp)
         }
     } else if (autostart) {
         vm_start();
+    } else {
+        bdrv_inactivate_all();
     }

and now, we have no dirty bitmaps between paused start and cont. And it is not comfortable, we can't query, can't do something with these bitmaps before vm start.

Quoted 11 lines
Quoted 5 lines

So, it looks like it's ok to just do not autoload bitmaps if we are in inactive mode. The difference would be that user will not see these bitmaps during migration. And he even may create bitmaps with same names, which will lead to fault. But it don't look like real problem.

You can't create persistent bitmaps on an inactive image anyway, because that would involve writes.

Conflicts with temporary bitmaps might be possible, though.

Kevin

Signature · 2 lines
Best regards,
Vladimir
author
#9 lore raw

PATCH v2 3/3 iotests: add dirty bitmap migration test

In reply to Vladimir Sementsov-Ogievskiy

The test creates two vms (vm_a, vm_b), create dirty bitmap in the first one, do several writes to corresponding device and then migrate vm_a to vm_b with dirty bitmaps.

For now, only migration through shared storage for persistent bitmaps is available, so it is tested here. Only offline variant is tested for now (a kind of suspend-resume), as it is needed to test that this case is successfully fixed by recent patch.

Signed-off-by Vladimir Sementsov-Ogievskiy <[email protected]>
Reviewed-by John Snow <[email protected]>
---
 tests/qemu-iotests/169     | 82 ++++++++++++++++++++++++++++++++++++++++++++++
 tests/qemu-iotests/169.out |  5 +++
 tests/qemu-iotests/group   |  1 +
 3 files changed, 88 insertions(+)
 create mode 100755 tests/qemu-iotests/169
 create mode 100644 tests/qemu-iotests/169.out
tests/qemu-iotests/169 new file +82 -0
new file mode 100755
index 0000000000..282970df8a
@@ -0,0 +1,82 @@
+#!/usr/bin/env python
+#
+# Tests for dirty bitmaps migration.
+#
+# Copyright (c) 2016-2017 Virtuozzo International GmbH. All rights reserved.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+import os
+import iotests
+import time
+from iotests import qemu_img
+
+disk = os.path.join(iotests.test_dir, 'disk')
+migfile = os.path.join(iotests.test_dir, 'migfile')
+
+class TestPersistentDirtyBitmapSuspendResume(iotests.QMPTestCase):
+
+    def tearDown(self):
+        self.vm_a.shutdown()
+        self.vm_b.shutdown()
+        os.remove(disk)
+        os.remove(migfile)
+
+    def setUp(self):
+        qemu_img('create', '-f', iotests.imgfmt, disk, '1M')
+
+        self.vm_a = iotests.VM(path_suffix='a').add_drive(disk)
+        self.vm_a.launch()
+
+        self.vm_b = iotests.VM(path_suffix='b').add_drive(disk)
+        self.vm_b.add_incoming("exec: cat '" + migfile + "'")
+
+    def test_migration_persistent_shared_offline(self):
+        """ A kind of suspend-resume """
+        granularity = 512
+        regions = [
+            { 'start': 0,           'count': 0x10000 },
+            { 'start': 0xf0000,     'count': 0x10000 },
+            { 'start': 0xa0201,     'count': 0x1000  }
+            ]
+
+        result = self.vm_a.qmp('block-dirty-bitmap-add', node='drive0',
+                               name='bitmap0', granularity=granularity,
+                               persistent=True, autoload=True)
+        self.assert_qmp(result, 'return', {});
+
+        for r in regions:
+            self.vm_a.hmp_qemu_io('drive0',
+                                  'write %d %d' % (r['start'], r['count']))
+
+        result = self.vm_a.qmp('x-debug-block-dirty-bitmap-sha256',
+                               node='drive0', name='bitmap0')
+        sha256 = result['return']['sha256']
+
+        result = self.vm_a.qmp('migrate', uri='exec:cat>' + migfile)
+        self.assert_qmp(result, 'return', {});
+        self.assertNotEqual(self.vm_a.event_wait("STOP"), None)
+        self.vm_a.shutdown()
+
+        self.vm_b.launch()
+        self.vm_b.event_wait("RESUME", timeout=10.0)
+
+        result = self.vm_b.qmp('x-debug-block-dirty-bitmap-sha256',
+                               node='drive0', name='bitmap0')
+        self.assert_qmp(result, 'return/sha256', sha256);
+
+
+if __name__ == '__main__':
+    iotests.main(supported_fmts=['qcow2'])
tests/qemu-iotests/169.out new file +5 -0
new file mode 100644
index 0000000000..ae1213e6f8
@@ -0,0 +1,5 @@
+.
+----------------------------------------------------------------------
+Ran 1 tests
+
+OK
tests/qemu-iotests/group +1 -0
index 3e688678dd..e879c7ebc7 100644
@@ -169,6 +169,7 @@
 162 auto quick
 163 rw auto quick
 165 rw auto quick
+169 rw auto quick
 170 rw auto quick
 171 rw auto quick
 172 auto
Signature · 1 line
2.11.1
#10 lore raw

Re: [Qemu-devel] [PATCH v2 3/3] iotests: add dirty bitmap migration test

Am 12.12.2017 um 17:04 hat Vladimir Sementsov-Ogievskiy geschrieben:

Quoted 13 lines

The test creates two vms (vm_a, vm_b), create dirty bitmap in the first one, do several writes to corresponding device and then migrate vm_a to vm_b with dirty bitmaps.

For now, only migration through shared storage for persistent bitmaps is available, so it is tested here. Only offline variant is tested for now (a kind of suspend-resume), as it is needed to test that this case is successfully fixed by recent patch.

Signed-off-by Vladimir Sementsov-Ogievskiy <[email protected]>
Reviewed-by John Snow <[email protected]>

[...]

tests/qemu-iotests/169 line 74

Quoted 2 lines
tests/qemu-iotests/169 new file +2 -0
+        self.vm_b.launch()
+        self.vm_b.event_wait("RESUME", timeout=10.0)

Wasn't this racy because the RESUME event may be sent before we connect to the socket?

Kevin

author
#11 lore raw

Re: [Qemu-devel] [PATCH v2 3/3] iotests: add dirty bitmap migration test

Quoted 10 lines · Kevin Wolf

Am 12.12.2017 um 17:04 hat Vladimir Sementsov-Ogievskiy geschrieben:

Quoted 9 lines

The test creates two vms (vm_a, vm_b), create dirty bitmap in the first one, do several writes to corresponding device and then migrate vm_a to vm_b with dirty bitmaps.

For now, only migration through shared storage for persistent bitmaps is available, so it is tested here. Only offline variant is tested for now (a kind of suspend-resume), as it is needed to test that this case is successfully fixed by recent patch.

Quoted 7 lines

tests/qemu-iotests/169 line 74

Quoted 5 lines
Signed-off-by Vladimir Sementsov-Ogievskiy <[email protected]>
Reviewed-by John Snow <[email protected]>
[...]
tests/qemu-iotests/169 new file +2 -0
+        self.vm_b.launch()
+        self.vm_b.event_wait("RESUME", timeout=10.0)

Wasn't this racy because the RESUME event may be sent before we connect to the socket?

Didn't know (and didn't faced) it. If it is so, it should be changed like you've changed similar place in my previous iotest.

Quoted 2 lines

Kevin

Signature · 2 lines
Best regards,
Vladimir
author
#12 lore raw
In reply to Vladimir Sementsov-Ogievskiy

Should qemu-stable be here?

Quoted 29 lines · Vladimir Sementsov-Ogievskiy

Hi all.

This fixes bitmaps migration through shared storage. Look at 02 for details.

The bug introduced in 2.10 with the whole qcow2 bitmaps feature, so qemu-stable in CC. However I doubt that someone really suffered from this.

v2:
John, thank you for reviewing v1.
changes:
add John's r-bs, change s/timeout=10/timeout=10.0/ in last patch and drop old 03 patch, related to this timeout fix.

Vladimir Sementsov-Ogievskiy (3):
qcow2-bitmap: add qcow2_reopen_bitmaps_rw_hint()
qcow2: handle reopening bitmaps on bdrv_invalidate_cache
iotests: add dirty bitmap migration test

  block/qcow2.h              |  2 ++
  block/qcow2-bitmap.c       | 15 ++++++++-
  block/qcow2.c              |  8 ++++-
  tests/qemu-iotests/169     | 82 ++++++++++++++++++++++++++++++++++++++++++++++
  tests/qemu-iotests/169.out |  5 +++
  tests/qemu-iotests/group   |  1 +
  6 files changed, 111 insertions(+), 2 deletions(-)

create mode 100755 tests/qemu-iotests/169
create mode 100644 tests/qemu-iotests/169.out

Signature · 2 lines
Best regards,
Vladimir