[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-block] [Qemu-devel] [PATCH 09/25] block/dirty-bitmap: add read
From: |
John Snow |
Subject: |
Re: [Qemu-block] [Qemu-devel] [PATCH 09/25] block/dirty-bitmap: add readonly field to BdrvDirtyBitmap |
Date: |
Fri, 19 May 2017 19:02:22 -0400 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.1.0 |
On 05/03/2017 08:25 AM, Vladimir Sementsov-Ogievskiy wrote:
> It will be needed in following commits for persistent bitmaps.
> If bitmap is loaded from read-only storage (and we can't mark it
> "in use" in this storage) corresponding BdrvDirtyBitmap should be
> read-only.
>
> Signed-off-by: Vladimir Sementsov-Ogievskiy <address@hidden>
> ---
> block/dirty-bitmap.c | 16 ++++++++++++++++
> include/block/dirty-bitmap.h | 3 +++
> 2 files changed, 19 insertions(+)
>
> diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c
> index 90af37287f..ab6a95cf41 100644
> --- a/block/dirty-bitmap.c
> +++ b/block/dirty-bitmap.c
> @@ -44,6 +44,8 @@ struct BdrvDirtyBitmap {
> int64_t size; /* Size of the bitmap (Number of sectors) */
> bool disabled; /* Bitmap is read-only */
> int active_iterators; /* How many iterators are active */
> + bool readonly; /* Bitmap is read-only and may be changed
> only
> + by deserialize* functions */
> QLIST_ENTRY(BdrvDirtyBitmap) list;
> };
>
> @@ -436,6 +438,7 @@ void bdrv_set_dirty_bitmap(BdrvDirtyBitmap *bitmap,
> int64_t cur_sector, int64_t nr_sectors)
> {
> assert(bdrv_dirty_bitmap_enabled(bitmap));
> + assert(!bdrv_dirty_bitmap_readonly(bitmap));
Doesn't this change the nature of the assertion?
We're going from
return !(bitmap->disabled || bitmap->successor);
to
!bitmap->readonly
That makes me a little nervous to ACK this patch, because the
correctness depends on how readonly is updated and manipulated in the
future, which makes it more prone to error.
> hbitmap_set(bitmap->bitmap, cur_sector, nr_sectors);
> }
>
> @@ -443,12 +446,14 @@ void bdrv_reset_dirty_bitmap(BdrvDirtyBitmap *bitmap,
> int64_t cur_sector, int64_t nr_sectors)
> {
> assert(bdrv_dirty_bitmap_enabled(bitmap));
> + assert(!bdrv_dirty_bitmap_readonly(bitmap));
> hbitmap_reset(bitmap->bitmap, cur_sector, nr_sectors);
> }
>
> void bdrv_clear_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap **out)
> {
> assert(bdrv_dirty_bitmap_enabled(bitmap));
> + assert(!bdrv_dirty_bitmap_readonly(bitmap));
> if (!out) {
> hbitmap_reset_all(bitmap->bitmap);
> } else {
> @@ -519,6 +524,7 @@ void bdrv_set_dirty(BlockDriverState *bs, int64_t
> cur_sector,
> if (!bdrv_dirty_bitmap_enabled(bitmap)) {
> continue;
> }
> + assert(!bdrv_dirty_bitmap_readonly(bitmap));
> hbitmap_set(bitmap->bitmap, cur_sector, nr_sectors);
> }
> }
> @@ -540,3 +546,13 @@ int64_t bdrv_get_meta_dirty_count(BdrvDirtyBitmap
> *bitmap)
> {
> return hbitmap_count(bitmap->meta);
> }
> +
> +bool bdrv_dirty_bitmap_readonly(const BdrvDirtyBitmap *bitmap)
> +{
> + return bitmap->readonly;
> +}
> +
> +void bdrv_dirty_bitmap_set_readonly(BdrvDirtyBitmap *bitmap)
> +{
> + bitmap->readonly = true;
> +}
> diff --git a/include/block/dirty-bitmap.h b/include/block/dirty-bitmap.h
> index 1e17729ac2..0aab5841f5 100644
> --- a/include/block/dirty-bitmap.h
> +++ b/include/block/dirty-bitmap.h
> @@ -75,4 +75,7 @@ void bdrv_dirty_bitmap_deserialize_ones(BdrvDirtyBitmap
> *bitmap,
> bool finish);
> void bdrv_dirty_bitmap_deserialize_finish(BdrvDirtyBitmap *bitmap);
>
> +bool bdrv_dirty_bitmap_readonly(const BdrvDirtyBitmap *bitmap);
> +void bdrv_dirty_bitmap_set_readonly(BdrvDirtyBitmap *bitmap);
> +
> #endif
>
- [Qemu-block] [PATCH v18 00/25] qcow2: persistent dirty bitmaps, Vladimir Sementsov-Ogievskiy, 2017/05/03
- [Qemu-block] [PATCH 13/25] block: introduce persistent dirty bitmaps, Vladimir Sementsov-Ogievskiy, 2017/05/03
- [Qemu-block] [PATCH 09/25] block/dirty-bitmap: add readonly field to BdrvDirtyBitmap, Vladimir Sementsov-Ogievskiy, 2017/05/03
- Re: [Qemu-block] [Qemu-devel] [PATCH 09/25] block/dirty-bitmap: add readonly field to BdrvDirtyBitmap,
John Snow <=
- Re: [Qemu-block] [PATCH 09/25] block/dirty-bitmap: add readonly field to BdrvDirtyBitmap, Max Reitz, 2017/05/29
- Re: [Qemu-block] [PATCH 09/25] block/dirty-bitmap: add readonly field to BdrvDirtyBitmap, Max Reitz, 2017/05/29
- Re: [Qemu-block] [PATCH 09/25] block/dirty-bitmap: add readonly field to BdrvDirtyBitmap, Max Reitz, 2017/05/31
- Re: [Qemu-block] [PATCH 09/25] block/dirty-bitmap: add readonly field to BdrvDirtyBitmap, Vladimir Sementsov-Ogievskiy, 2017/05/31
- Re: [Qemu-block] [PATCH 09/25] block/dirty-bitmap: add readonly field to BdrvDirtyBitmap, Max Reitz, 2017/05/31