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Re: [RFC PATCH v3 10/27] qcow2: Update get/set_l2_entry() and add get/se
From: |
Max Reitz |
Subject: |
Re: [RFC PATCH v3 10/27] qcow2: Update get/set_l2_entry() and add get/set_l2_bitmap() |
Date: |
Thu, 20 Feb 2020 17:27:28 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 |
On 22.12.19 12:36, Alberto Garcia wrote:
> Extended L2 entries are 128-bit wide: 64 bits for the entry itself and
> 64 bits for the subcluster allocation bitmap.
>
> In order to support them correctly get/set_l2_entry() need to be
> updated so they take the entry width into account in order to
> calculate the correct offset.
>
> This patch also adds the get/set_l2_bitmap() functions that are
> used to access the bitmaps. For convenience we allow calling
> get_l2_bitmap() on images without subclusters, although the caller
> does not need and should ignore the returned value.
>
> Signed-off-by: Alberto Garcia <address@hidden>
> ---
> block/qcow2.h | 22 ++++++++++++++++++++++
> 1 file changed, 22 insertions(+)
>
> diff --git a/block/qcow2.h b/block/qcow2.h
> index 8be020bb76..64b0a814f4 100644
> --- a/block/qcow2.h
> +++ b/block/qcow2.h
> @@ -518,15 +518,37 @@ static inline size_t l2_entry_size(BDRVQcow2State *s)
[...]
> +static inline uint64_t get_l2_bitmap(BDRVQcow2State *s, uint64_t *l2_slice,
> + int idx)
> +{
> + if (has_subclusters(s)) {
> + idx *= l2_entry_size(s) / sizeof(uint64_t);
> + return be64_to_cpu(l2_slice[idx + 1]);
> + } else {
> + /* For convenience only; the caller should ignore this value. */
> + return 0;
Is there a reason you decided not to return the first subcluster as
allocated? (As you had proposed in v2)
Reviewed-by: Max Reitz <address@hidden>
> + }
> +}
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- Re: [RFC PATCH v3 10/27] qcow2: Update get/set_l2_entry() and add get/set_l2_bitmap(),
Max Reitz <=