Re: [Qemu-devel] [PATCH v3 2/8] VMDK: add twoGbMaxExtentSparse support

[Kevin Wolf <kwolf@redhat.com>]

Am 12.08.2011 17:19, schrieb Fam Zheng:
> Add twoGbMaxExtentSparse support. Introduce vmdk_free_last_extent.
> 
> Signed-off-by: Fam Zheng <famcool@gmail.com>
> ---
>  block/vmdk.c |  133 ++++++++++++++++++++++++++++++++++++----------------------
>  1 files changed, 83 insertions(+), 50 deletions(-)
> 
> diff --git a/block/vmdk.c b/block/vmdk.c
> index e22a893..ab15840 100644
> --- a/block/vmdk.c
> +++ b/block/vmdk.c
> @@ -174,6 +174,17 @@ static void vmdk_free_extents(BlockDriverState *bs)
>      qemu_free(s->extents);
>  }
>  
> +static void vmdk_free_last_extent(BlockDriverState *bs)
> +{
> +    BDRVVmdkState *s = bs->opaque;
> +
> +    if (s->num_extents == 0) {
> +        return;
> +    }
> +    s->num_extents--;
> +    s->extents = qemu_realloc(s->extents, s->num_extents * sizeof(VmdkExtent));
> +}
> +
>  static uint32_t vmdk_read_cid(BlockDriverState *bs, int parent)
>  {
>      char desc[DESC_SIZE];
> @@ -357,18 +368,18 @@ static int vmdk_init_tables(BlockDriverState *bs, VmdkExtent *extent)
>      return ret;
>  }
>  
> -static int vmdk_open_vmdk3(BlockDriverState *bs, int flags)
> +static int vmdk_open_vmdk3(BlockDriverState *bs,
> +                           BlockDriverState *file,
> +                           int flags)
>  {
>      int ret;
>      uint32_t magic;
>      VMDK3Header header;
> -    BDRVVmdkState *s = bs->opaque;
>      VmdkExtent *extent;
>  
> -    s->desc_offset = 0x200;
> -    ret = bdrv_pread(bs->file, sizeof(magic), &header, sizeof(header));
> +    ret = bdrv_pread(file, sizeof(magic), &header, sizeof(header));
>      if (ret < 0) {
> -        goto fail;
> +        return ret;
>      }
>      extent = vmdk_add_extent(bs,
>                               bs->file, false,
> @@ -378,58 +389,45 @@ static int vmdk_open_vmdk3(BlockDriverState *bs, int flags)
>                               le32_to_cpu(header.granularity));
>      ret = vmdk_init_tables(bs, extent);
>      if (ret) {
> -        /* vmdk_init_tables cleans up on fail, so only free allocation of
> -         * vmdk_add_extent here. */
> -        goto fail;
> +        /* free extent allocated by vmdk_add_extent */
> +        vmdk_free_last_extent(bs);
>      }
> -    return 0;
> - fail:
> -    vmdk_free_extents(bs);
>      return ret;
>  }
>  
> -static int vmdk_open_vmdk4(BlockDriverState *bs, int flags)
> +static int vmdk_open_vmdk4(BlockDriverState *bs,
> +                           BlockDriverState *file,
> +                           int flags)
>  {
>      int ret;
>      uint32_t magic;
>      uint32_t l1_size, l1_entry_sectors;
>      VMDK4Header header;
> -    BDRVVmdkState *s = bs->opaque;
>      VmdkExtent *extent;
>  
> -    s->desc_offset = 0x200;
> -    ret = bdrv_pread(bs->file, sizeof(magic), &header, sizeof(header));
> +    ret = bdrv_pread(file, sizeof(magic), &header, sizeof(header));
>      if (ret < 0) {
> -        goto fail;
> +        return ret;
>      }
>      l1_entry_sectors = le32_to_cpu(header.num_gtes_per_gte)
>                          * le64_to_cpu(header.granularity);
> +    if (l1_entry_sectors <= 0) {
> +        return -EINVAL;
> +    }
>      l1_size = (le64_to_cpu(header.capacity) + l1_entry_sectors - 1)
>                  / l1_entry_sectors;
> -    extent = vmdk_add_extent(bs, bs->file, false,
> +    extent = vmdk_add_extent(bs, file, false,
>                            le64_to_cpu(header.capacity),
>                            le64_to_cpu(header.gd_offset) << 9,
>                            le64_to_cpu(header.rgd_offset) << 9,
>                            l1_size,
>                            le32_to_cpu(header.num_gtes_per_gte),
>                            le64_to_cpu(header.granularity));
> -    if (extent->l1_entry_sectors <= 0) {
> -        ret = -EINVAL;
> -        goto fail;
> -    }
> -    /* try to open parent images, if exist */
> -    ret = vmdk_parent_open(bs);
> -    if (ret) {
> -        goto fail;
> -    }
> -    s->parent_cid = vmdk_read_cid(bs, 1);
>      ret = vmdk_init_tables(bs, extent);
>      if (ret) {
> -        goto fail;
> +        /* free extent allocated by vmdk_add_extent */
> +        vmdk_free_last_extent(bs);
>      }
> -    return 0;
> - fail:
> -    vmdk_free_extents(bs);
>      return ret;
>  }
>  
> @@ -460,6 +458,31 @@ static int vmdk_parse_description(const char *desc, const char *opt_name,
>      return 0;
>  }
>  
> +/* Open an extent file and append to bs array */
> +static int vmdk_open_sparse(BlockDriverState *bs,
> +                            BlockDriverState *file,
> +                            int flags)
> +{
> +    uint32_t magic;
> +
> +    if (bdrv_pread(file, 0, &magic, sizeof(magic)) != sizeof(magic)) {
> +        return -EIO;
> +    }
> +
> +    magic = be32_to_cpu(magic);
> +    switch (magic) {
> +        case VMDK3_MAGIC:
> +            return vmdk_open_vmdk3(bs, file, flags);
> +            break;
> +        case VMDK4_MAGIC:
> +            return vmdk_open_vmdk4(bs, file, flags);
> +            break;
> +        default:
> +            return -EINVAL;
> +            break;
> +    }
> +}
> +
>  static int vmdk_parse_extents(const char *desc, BlockDriverState *bs,
>          const char *desc_file_path)
>  {
> @@ -470,6 +493,8 @@ static int vmdk_parse_extents(const char *desc, BlockDriverState *bs,
>      const char *p = desc;
>      int64_t sectors = 0;
>      int64_t flat_offset;
> +    char extent_path[PATH_MAX];
> +    BlockDriverState *extent_file;
>  
>      while (*p) {
>          /* parse extent line:
> @@ -504,24 +529,29 @@ static int vmdk_parse_extents(const char *desc, BlockDriverState *bs,
>              goto next_line;
>          }
>  
> +        path_combine(extent_path, sizeof(extent_path),
> +                desc_file_path, fname);
> +        ret = bdrv_file_open(&extent_file, extent_path, bs->open_flags);
> +        if (ret) {
> +            return ret;
> +        }
> +
>          /* save to extents array */
>          if (!strcmp(type, "FLAT")) {
>              /* FLAT extent */
> -            char extent_path[PATH_MAX];
> -            BlockDriverState *extent_file;
>              VmdkExtent *extent;
>  
> -            path_combine(extent_path, sizeof(extent_path),
> -                    desc_file_path, fname);
> -            ret = bdrv_file_open(&extent_file, extent_path, bs->open_flags);
> -            if (ret) {
> -                return ret;
> -            }
>              extent = vmdk_add_extent(bs, extent_file, true, sectors,
>                              0, 0, 0, 0, sectors);
>              extent->flat_start_offset = flat_offset;
> +        } else if (!strcmp(type, "SPARSE")) {
> +            /* SPARSE extent */
> +            ret = vmdk_open_sparse(bs, extent_file, bs->open_flags);
> +            if (ret) {
> +                bdrv_delete(extent_file);
> +                return ret;
> +            }
>          } else {
> -            /* SPARSE extent, not supported for now */
>              fprintf(stderr,
>                  "VMDK: Not supported extent type \"%s\""".\n", type);
>              return -ENOTSUP;

I think you'll leak extent_file in the error case. I'll merge the patch
anyway, please fix on top.

Kevin