Re: [Qemu-devel] [PATCH 4/4] qapi: add block-dirty-bitmap-merge

[Vladimir Sementsov-Ogievskiy]

13.11.2017 19:20, Vladimir Sementsov-Ogievskiy wrote:
> Signed-off-by: Vladimir Sementsov-Ogievskiy <address@hidden>
> ---
>   qapi/block-core.json         | 38 ++++++++++++++++++++++++++++++++++++++
>   include/block/dirty-bitmap.h |  2 ++
>   block/dirty-bitmap.c         | 17 +++++++++++++++++
>   blockdev.c                   | 30 ++++++++++++++++++++++++++++++
>   4 files changed, 87 insertions(+)
>
> diff --git a/qapi/block-core.json b/qapi/block-core.json
> index 487744c16b..074c7c4cb9 100644
> --- a/qapi/block-core.json
> +++ b/qapi/block-core.json
> @@ -1604,6 +1604,20 @@
>               '*persistent': 'bool', '*autoload': 'bool' } }
>   
>   ##
> +# @BlockDirtyBitmapMerge:
> +#
> +# @node: name of device/node which the bitmap is tracking
> +#
> +# @dst_name: name of the destination dirty bitmap
> +#
> +# @src_name: name of the source dirty bitmap
> +#
> +# Since: 2.12
> +##
> +{ 'struct': 'BlockDirtyBitmapMerge',
> +  'data': { 'node': 'str', 'dst_name': 'str', 'src_name': 'str' } }
> +
> +##
>   # @block-dirty-bitmap-add:
>   #
>   # Create a dirty bitmap with a name on the node, and start tracking the 
> writes.
> @@ -1714,6 +1728,30 @@
>         'data': 'BlockDirtyBitmap' }
>   
>   ##
> +# @block-dirty-bitmap-merge:
> +#
> +# Merge @src_name dirty bitmap to @dst_name dirty bitmap. @src_name dirty
> +# bitmap is unchanged.
> +#
> +# Returns: nothing on success
> +#          If @node is not a valid block device, DeviceNotFound
> +#          If @dst_name or @src_name is not found, GenericError
> +#          If bitmaps has different sizes or granularities, GenericError
> +#
> +# Since: 2.12
> +#
> +# Example:
> +#
> +# -> { "execute": "block-dirty-bitmap-merge",
> +#      "arguments": { "node": "drive0", "dst_name": "bitmap0",
> +#                     "src_name": "bitmap1" } }
> +# <- { "return": {} }
> +#
> +##
> +      { 'command': 'block-dirty-bitmap-merge',
> +        'data': 'BlockDirtyBitmapMerge' }
> +
> +##
>   # @BlockDirtyBitmapSha256:
>   #
>   # SHA256 hash of dirty bitmap data
> diff --git a/include/block/dirty-bitmap.h b/include/block/dirty-bitmap.h
> index 3579a7597c..6d797b4a2e 100644
> --- a/include/block/dirty-bitmap.h
> +++ b/include/block/dirty-bitmap.h
> @@ -68,6 +68,8 @@ void bdrv_dirty_bitmap_set_readonly(BdrvDirtyBitmap *bitmap, 
> bool value);
>   void bdrv_dirty_bitmap_set_autoload(BdrvDirtyBitmap *bitmap, bool autoload);
>   void bdrv_dirty_bitmap_set_persistance(BdrvDirtyBitmap *bitmap,
>                                          bool persistent);
> +void bdrv_merge_dirty_bitmap(BdrvDirtyBitmap *dest, const BdrvDirtyBitmap *src,
> +                             Error **errp);
>   
>   /* Functions that require manual locking.  */
>   void bdrv_dirty_bitmap_lock(BdrvDirtyBitmap *bitmap);
> diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c
> index 2a0bcd9e51..f60c145e9c 100644
> --- a/block/dirty-bitmap.c
> +++ b/block/dirty-bitmap.c
> @@ -719,3 +719,20 @@ char *bdrv_dirty_bitmap_sha256(const BdrvDirtyBitmap 
> *bitmap, Error **errp)
>   {
>       return hbitmap_sha256(bitmap->bitmap, errp);
>   }
> +
> +void bdrv_merge_dirty_bitmap(BdrvDirtyBitmap *dest, const BdrvDirtyBitmap *src,
> +                             Error **errp)
> +{
> +    qemu_mutex_lock(dest->mutex);
> +    qemu_mutex_lock(src->mutex);

it's the same mutex, so it can't be locked twice

> +
> +    assert(bdrv_dirty_bitmap_enabled(dest));
> +    assert(!bdrv_dirty_bitmap_readonly(dest));
> +
> +    if (!hbitmap_merge(dest->bitmap, src->bitmap)) {
> +        error_setg(errp, "Bitmaps are incompatible and can't be merged");
> +    }
> +
> +    qemu_mutex_lock(src->mutex);
> +    qemu_mutex_lock(dest->mutex);
unlock
> +}
> diff --git a/blockdev.c b/blockdev.c
> index f6595ddcd3..922e8da39b 100644
> --- a/blockdev.c
> +++ b/blockdev.c
> @@ -2948,6 +2948,36 @@ void qmp_block_dirty_bitmap_disable(const char *node, 
> const char *name,
>       bdrv_disable_dirty_bitmap(bitmap);
>   }
>   
> +void qmp_block_dirty_bitmap_merge(const char *node, const char *dst_name,
> +                                  const char *src_name, Error **errp)
> +{
> +    BlockDriverState *bs;
> +    BdrvDirtyBitmap *dst, *src;
> +
> +    dst = block_dirty_bitmap_lookup(node, dst_name, &bs, errp);
> +    if (!dst || !bs) {
> +        return;
> +    }
> +
> +    if (bdrv_dirty_bitmap_frozen(dst)) {
> +        error_setg(errp, "Bitmap '%s' is frozen and cannot be modified",
> +                   dst_name);
> +        return;
> +    } else if (bdrv_dirty_bitmap_readonly(dst)) {
> +        error_setg(errp, "Bitmap '%s' is readonly and cannot be modified",
> +                   dst_name);
> +        return;
> +    }
> +
> +    src = bdrv_find_dirty_bitmap(bs, src_name);
> +    if (!src) {
> +        error_setg(errp, "Dirty bitmap '%s' not found", src_name);
> +        return;
> +    }
> +
> +    bdrv_merge_dirty_bitmap(dst, src, errp);
> +}
> +
>   BlockDirtyBitmapSha256 *qmp_x_debug_block_dirty_bitmap_sha256(const char 
> *node,
>                                                                 const char 
> *name,
>                                                                 Error **errp)


--
Best regards,
Vladimir