Re: [Qemu-devel] [PATCH] Fix for qemu-img info to supply FORMAT values for SPARSE extents

[Fam Zheng]

On Mon, 03/31 12:05, Shwetha Mathangi Chandra Choodamani wrote:
> This patch fixes the qemu-img info bug to return the right format of an 
> extent. Changes applicable to both VMDK3 and VMDK4 type headers.
> Signed-off-by: Shwetha Mathangi Chandra Choodamani 
> <saphira.brightsca...@gmail.com>
> ---
>  block/vmdk.c |   42 ++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 42 insertions(+)
> 
> diff --git a/block/vmdk.c b/block/vmdk.c
> index b69988d..81fcb92 100644
> --- a/block/vmdk.c
> +++ b/block/vmdk.c
> @@ -515,6 +515,28 @@ static int vmdk_open_vmfs_sparse(BlockDriverState *bs,
>                            le32_to_cpu(header.granularity),
>                            &extent,
>                            errp);
> +    char access[11];
> +    char type[11];
> +    char fname[512];
> +    int64_t sectors = 0;
> +    int64_t flat_offset;
> +    int64_t size;
> +    size = bdrv_getlength(file);
> +    char *buf;

Please put variable declarations in the beginning of code block.

> +    buf = g_malloc0(size + 1);

buf is allocated and incremented, but the buffer is never released.

> +    bdrv_pread(file, sizeof(magic), buf, size);
> +    while (strcmp(access, "RW")) {

access is used before initialization. Does this work?

> +        while (*buf) {
> +            sscanf(buf, "%10s %" SCNd64 " %10s \"%511[^\n\r\"]\" %" SCNd64,
> +             access, &sectors, type, fname, &flat_offset);

Better to align the parameters with first line:

                      access, &sectors, ...);


However I don't think VMDK3 needs this fix, what we care here is
monolithicSparse, which is specifically VMDK4.

> +            if (*buf == '\n') {
> +                buf++;
> +                break;
> +            }
> +            buf++;
> +        }
> +    }
> +    extent->type = g_strdup(type);
>      if (ret < 0) {
>          return ret;
>      }
> @@ -566,6 +588,12 @@ static int vmdk_open_vmdk4(BlockDriverState *bs,
>      VmdkExtent *extent;
>      BDRVVmdkState *s = bs->opaque;
>      int64_t l1_backup_offset = 0;
> +    char access[11];
> +    char type[11];
> +    char fname[512];
> +    int64_t sectors = 0;
> +    int64_t flat_offset;
> +
>  
>      ret = bdrv_pread(file, sizeof(magic), &header, sizeof(header));
>      if (ret < 0) {
> @@ -589,6 +617,19 @@ static int vmdk_open_vmdk4(BlockDriverState *bs,
>  
>      if (!s->create_type) {
>          s->create_type = g_strdup("monolithicSparse");

For VMDK4, this duplicates with vmdk_parse_extents(). I think this patch can be
simplified by moving this if block after vmdk_add_extent, where the "extent"
variable is set and we can set its type field safely.

And please fix in the same way for streamOptimized.

Thanks,
Fam

> +        uint64_t desc_offset = le64_to_cpu(header.desc_offset);
> +        char *buf = vmdk_read_desc(file, desc_offset<<9, errp);
> +        while (strcmp(access, "RW")) {
> +            while (*buf) {
> +                sscanf(buf, "%10s %" SCNd64 " %10s \"%511[^\n\r\"]\" %" 
> SCNd64,
> +                 access, &sectors, type, fname, &flat_offset);
> +            if (*buf == '\n') {
> +                buf++;
> +                break;
> +            }
> +            buf++;
> +            }
> +        }
>      }
>  
>      if (le64_to_cpu(header.gd_offset) == VMDK4_GD_AT_END) {
> @@ -697,6 +738,7 @@ static int vmdk_open_vmdk4(BlockDriverState *bs,
>      extent->has_marker = le32_to_cpu(header.flags) & VMDK4_FLAG_MARKER;
>      extent->version = le32_to_cpu(header.version);
>      extent->has_zero_grain = le32_to_cpu(header.flags) & 
> VMDK4_FLAG_ZERO_GRAIN;
> +    extent->type = g_strdup(type);
>      ret = vmdk_init_tables(bs, extent, errp);
>      if (ret) {
>          /* free extent allocated by vmdk_add_extent */
> -- 
> 1.7.9.5
>