Re: [PATCH 02/17] qcow2: List autoclear bit names in header

[Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>]

31.01.2020 20:44, Eric Blake wrote:
> The feature table is supposed to advertise the name of all feature
> bits that we support; however, we forgot to update the table for
> autoclear bits.  While at it, move the table to read-only memory in
> code, and tweak the qcow2 spec to name the second autoclear bit.
> Update iotests that are affected by the longer header length.
> 
> Fixes: 88ddffae
> Fixes: 93c24936
> Signed-off-by: Eric Blake <eblake@redhat.com>
> ---
>   block/qcow2.c              | 12 +++++++++++-
>   docs/interop/qcow2.txt     |  3 ++-
>   tests/qemu-iotests/031.out |  8 ++++----
>   tests/qemu-iotests/036.out |  4 ++--
>   tests/qemu-iotests/061.out | 14 +++++++-------
>   5 files changed, 26 insertions(+), 15 deletions(-)
> 
> diff --git a/block/qcow2.c b/block/qcow2.c
> index 30fd3d13032a..d3e7709ac2b4 100644
> --- a/block/qcow2.c
> +++ b/block/qcow2.c
> @@ -2821,7 +2821,7 @@ int qcow2_update_header(BlockDriverState *bs)
> 
>       /* Feature table */
>       if (s->qcow_version >= 3) {
> -        Qcow2Feature features[] = {
> +        static const Qcow2Feature features[] = {
>               {
>                   .type = QCOW2_FEAT_TYPE_INCOMPATIBLE,
>                   .bit  = QCOW2_INCOMPAT_DIRTY_BITNR,
> @@ -2842,6 +2842,16 @@ int qcow2_update_header(BlockDriverState *bs)
>                   .bit  = QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR,
>                   .name = "lazy refcounts",
>               },
> +            {
> +                .type = QCOW2_FEAT_TYPE_AUTOCLEAR,
> +                .bit  = QCOW2_AUTOCLEAR_BITMAPS_BITNR,
> +                .name = "consistent bitmaps",

Hmm, what do you mean by "consistent" ? Each bitmap has own in_use flag, and my be
"inconsistent" on its own.

I'd prefer to name it just "bitmaps", as extension is named "Bitmaps". With this change:
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

> +            },
> +            {
> +                .type = QCOW2_FEAT_TYPE_AUTOCLEAR,
> +                .bit  = QCOW2_AUTOCLEAR_DATA_FILE_RAW_BITNR,
> +                .name = "raw external data",
> +            },
>           };
> 
>           ret = header_ext_add(buf, QCOW2_EXT_MAGIC_FEATURE_TABLE,
> diff --git a/docs/interop/qcow2.txt b/docs/interop/qcow2.txt
> index af5711e53371..8510d74c8079 100644
> --- a/docs/interop/qcow2.txt
> +++ b/docs/interop/qcow2.txt
> @@ -138,7 +138,8 @@ in the description of a field.
>                                   bit is unset, the bitmaps extension data must be
>                                   considered inconsistent.
> 
> -                    Bit 1:      If this bit is set, the external data file can
> +                    Bit 1:      Raw external data bit
> +                                If this bit is set, the external data file can
>                                   be read as a consistent standalone raw image
>                                   without looking at the qcow2 metadata.
> 
> diff --git a/tests/qemu-iotests/031.out b/tests/qemu-iotests/031.out
> index d535e407bc30..46f97c5a4ea4 100644
> --- a/tests/qemu-iotests/031.out
> +++ b/tests/qemu-iotests/031.out
> @@ -117,7 +117,7 @@ header_length             104
> 
>   Header extension:
>   magic                     0x6803f857
> -length                    192
> +length                    288
>   data                      <binary>
> 
>   Header extension:
> @@ -150,7 +150,7 @@ header_length             104
> 
>   Header extension:
>   magic                     0x6803f857
> -length                    192
> +length                    288
>   data                      <binary>
> 
>   Header extension:
> @@ -164,7 +164,7 @@ No errors were found on the image.
> 
>   magic                     0x514649fb
>   version                   3
> -backing_file_offset       0x178
> +backing_file_offset       0x1d8
>   backing_file_size         0x17
>   cluster_bits              16
>   size                      67108864
> @@ -188,7 +188,7 @@ data                      'host_device'
> 
>   Header extension:
>   magic                     0x6803f857
> -length                    192
> +length                    288
>   data                      <binary>
> 
>   Header extension:
> diff --git a/tests/qemu-iotests/036.out b/tests/qemu-iotests/036.out
> index 0b52b934e115..23b699ce0622 100644
> --- a/tests/qemu-iotests/036.out
> +++ b/tests/qemu-iotests/036.out
> @@ -26,7 +26,7 @@ compatible_features       []
>   autoclear_features        [63]
>   Header extension:
>   magic                     0x6803f857
> -length                    192
> +length                    288
>   data                      <binary>
> 
> 
> @@ -38,7 +38,7 @@ compatible_features       []
>   autoclear_features        []
>   Header extension:
>   magic                     0x6803f857
> -length                    192
> +length                    288
>   data                      <binary>
> 
>   *** done
> diff --git a/tests/qemu-iotests/061.out b/tests/qemu-iotests/061.out
> index 8b3091a412bc..413cc4e0f4ab 100644
> --- a/tests/qemu-iotests/061.out
> +++ b/tests/qemu-iotests/061.out
> @@ -26,7 +26,7 @@ header_length             104
> 
>   Header extension:
>   magic                     0x6803f857
> -length                    192
> +length                    288
>   data                      <binary>
> 
>   magic                     0x514649fb
> @@ -84,7 +84,7 @@ header_length             104
> 
>   Header extension:
>   magic                     0x6803f857
> -length                    192
> +length                    288
>   data                      <binary>
> 
>   magic                     0x514649fb
> @@ -140,7 +140,7 @@ header_length             104
> 
>   Header extension:
>   magic                     0x6803f857
> -length                    192
> +length                    288
>   data                      <binary>
> 
>   ERROR cluster 5 refcount=0 reference=1
> @@ -195,7 +195,7 @@ header_length             104
> 
>   Header extension:
>   magic                     0x6803f857
> -length                    192
> +length                    288
>   data                      <binary>
> 
>   magic                     0x514649fb
> @@ -264,7 +264,7 @@ header_length             104
> 
>   Header extension:
>   magic                     0x6803f857
> -length                    192
> +length                    288
>   data                      <binary>
> 
>   read 65536/65536 bytes at offset 44040192
> @@ -298,7 +298,7 @@ header_length             104
> 
>   Header extension:
>   magic                     0x6803f857
> -length                    192
> +length                    288
>   data                      <binary>
> 
>   ERROR cluster 5 refcount=0 reference=1
> @@ -327,7 +327,7 @@ header_length             104
> 
>   Header extension:
>   magic                     0x6803f857
> -length                    192
> +length                    288
>   data                      <binary>
> 
>   read 131072/131072 bytes at offset 0
> 


-- 
Best regards,
Vladimir