Re: [Qemu-block] [PATCH 09/24] qcow2: add .bdrv_load_autoloading_dirty_bitmaps

[Max Reitz]

On 23.01.2017 13:10, Vladimir Sementsov-Ogievskiy wrote:
> Auto loading bitmaps are bitmaps in Qcow2, with the AUTO flag set. They
> are loaded when the image is opened and become BdrvDirtyBitmaps for the
> corresponding drive.
> 
> Extra data in bitmaps is not supported for now.
> 
> Signed-off-by: Vladimir Sementsov-Ogievskiy <address@hidden>
> ---
>  block/Makefile.objs  |   2 +-
>  block/qcow2-bitmap.c | 712 
> +++++++++++++++++++++++++++++++++++++++++++++++++++
>  block/qcow2.c        |   2 +
>  block/qcow2.h        |   3 +
>  4 files changed, 718 insertions(+), 1 deletion(-)
>  create mode 100644 block/qcow2-bitmap.c
> 
> diff --git a/block/Makefile.objs b/block/Makefile.objs
> index 67a036a1df..b8b6cf38a0 100644
> --- a/block/Makefile.objs
> +++ b/block/Makefile.objs
> @@ -1,5 +1,5 @@
>  block-obj-y += raw_bsd.o qcow.o vdi.o vmdk.o cloop.o bochs.o vpc.o vvfat.o 
> dmg.o

s/raw_bsd/raw-format/

(yes, just contextual, but prevents git from taking the patch as-is)

> -block-obj-y += qcow2.o qcow2-refcount.o qcow2-cluster.o qcow2-snapshot.o 
> qcow2-cache.o
> +block-obj-y += qcow2.o qcow2-refcount.o qcow2-cluster.o qcow2-snapshot.o 
> qcow2-cache.o qcow2-bitmap.o
>  block-obj-y += qed.o qed-gencb.o qed-l2-cache.o qed-table.o qed-cluster.o
>  block-obj-y += qed-check.o
>  block-obj-y += vhdx.o vhdx-endian.o vhdx-log.o
> diff --git a/block/qcow2-bitmap.c b/block/qcow2-bitmap.c
> new file mode 100644
> index 0000000000..758622dcfc
> --- /dev/null
> +++ b/block/qcow2-bitmap.c

[...]

> +static int update_ext_header_and_dir_in_place(BlockDriverState *bs,
> +                                              Qcow2BitmapList *bm_list)
> +{
> +    BDRVQcow2State *s = bs->opaque;
> +    int ret;
> +
> +    if (!(s->autoclear_features & QCOW2_AUTOCLEAR_BITMAPS) ||
> +        bm_list == NULL || QSIMPLEQ_EMPTY(bm_list) ||
> +        bitmap_list_count(bm_list) != s->nb_bitmaps)
> +    {
> +        return -EINVAL;
> +    }
> +
> +    s->autoclear_features &= ~(uint64_t)QCOW2_AUTOCLEAR_BITMAPS;
> +    ret = update_header_sync(bs);
> +    if (ret < 0) {
> +        return ret;
> +    }
> +
> +    /* autoclear bit is not set, so we can safely update bitmap directory */
> +
> +    ret = bitmap_list_store(bs, bm_list, &s->bitmap_directory_offset,
> +                            &s->bitmap_directory_size, true);
> +    if (ret < 0) {
> +        /* autoclear bit is cleared, so all leaked clusters would be removed 
> on
> +         * qemu-img check */

OK, so then all the bitmaps are gone... Well, if you say that's OK, I'll
trust you. O:-)

Reviewed-by: Max Reitz <address@hidden>

> +        return ret;
> +    }
> +
> +    s->autoclear_features |= QCOW2_AUTOCLEAR_BITMAPS;
> +    return update_header_sync(bs);
> +}

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