[libvirt] [PATCH libvirt] storage: learn to create qcow2 with preallocation

Christophe Fergeau cfergeau at redhat.com
Wed May 16 11:52:02 UTC 2012


ACK

On Wed, May 16, 2012 at 01:21:33PM +0200, Marc-André Lureau wrote:
> Use preallocation mode specified in volume XML format when running
> qemu-img.
> ---
>  src/storage/storage_backend.c |   70 +++++++++++++++++++++++++++++++++++------
>  1 file changed, 60 insertions(+), 10 deletions(-)
> 
> diff --git a/src/storage/storage_backend.c b/src/storage/storage_backend.c
> index caac2f8..523b6e2 100644
> --- a/src/storage/storage_backend.c
> +++ b/src/storage/storage_backend.c
> @@ -645,6 +645,38 @@ cleanup:
>      return ret;
>  }
>  
> +static char *
> +virStorageQemuImgOptionsStr(virStorageVolDefPtr vol)
> +{
> +    virBuffer buf = VIR_BUFFER_INITIALIZER;
> +    bool do_encryption = (vol->target.encryption != NULL);
> +    const char *backingType = vol->backingStore.path ?
> +        virStorageFileFormatTypeToString(vol->backingStore.format) : NULL;
> +    bool comma = false;
> +    const char *preallocation = vol->preallocation != VIR_STORAGE_PREALLOCATION_NONE ?
> +        virStoragePreallocationModeTypeToString(vol->preallocation) : NULL;
> +
> +    if (backingType) {
> +        virBufferAddLit(&buf, "backing_fmt=");
> +        virBufferAdd(&buf, backingType, -1);
> +        comma = true;
> +    }
> +
> +    if (do_encryption) {
> +        virBufferAdd(&buf, comma ? "," : "", -1);
> +        virBufferAddLit(&buf, "encryption=on");
> +        comma = true;
> +    }
> +
> +    if (preallocation) {
> +        virBufferAdd(&buf, comma ? "," : "", -1);
> +        virBufferAddLit(&buf, "preallocation=");
> +        virBufferAdd(&buf, preallocation, -1);
> +        comma = true;
> +    }
> +
> +    return virBufferContentAndReset(&buf);
> +}
>  
>  static int
>  virStorageBackendCreateQemuImg(virConnectPtr conn,
> @@ -658,7 +690,9 @@ virStorageBackendCreateQemuImg(virConnectPtr conn,
>      int imgformat = -1;
>      virCommandPtr cmd = NULL;
>      bool do_encryption = (vol->target.encryption != NULL);
> +    bool with_preallocation = (vol->preallocation != VIR_STORAGE_PREALLOCATION_NONE);
>      unsigned long long int size_arg;
> +    char *options;
>  
>      virCheckFlags(0, -1);
>  
> @@ -689,6 +723,12 @@ virStorageBackendCreateQemuImg(virConnectPtr conn,
>          return -1;
>      }
>  
> +    if (vol->target.format != VIR_STORAGE_FILE_QCOW2 && with_preallocation) {
> +        virStorageReportError(VIR_ERR_CONFIG_UNSUPPORTED,
> +                              _("Preallocation is only available with qcow2"));
> +        return -1;
> +    }
> +
>      if (vol->backingStore.path) {
>          int accessRetCode = -1;
>          char *absolutePath = NULL;
> @@ -781,16 +821,22 @@ virStorageBackendCreateQemuImg(virConnectPtr conn,
>      if (imgformat < 0)
>          goto cleanup;
>  
> +    if (imgformat != QEMU_IMG_BACKING_FORMAT_OPTIONS && with_preallocation)
> +        VIR_INFO("Preallocation not supported with this version of qemu-img");
> +
>      cmd = virCommandNew(create_tool);
>  
>      if (inputvol) {
>          virCommandAddArgList(cmd, "convert", "-f", inputType, "-O", type,
>                               inputPath, vol->target.path, NULL);
>  
> -        if (do_encryption) {
> -            if (imgformat == QEMU_IMG_BACKING_FORMAT_OPTIONS) {
> -                virCommandAddArgList(cmd, "-o", "encryption=on", NULL);
> -            } else {
> +        if (imgformat == QEMU_IMG_BACKING_FORMAT_OPTIONS) {
> +            virCommandAddArg(cmd, "-o");
> +            options = virStorageQemuImgOptionsStr(vol);
> +            virCommandAddArg(cmd, options);
> +            VIR_FREE(options);
> +        } else {
> +            if (do_encryption) {
>                  virCommandAddArg(cmd, "-e");
>              }
>          }
> @@ -811,10 +857,11 @@ virStorageBackendCreateQemuImg(virConnectPtr conn,
>  
>          case QEMU_IMG_BACKING_FORMAT_OPTIONS:
>              virCommandAddArg(cmd, "-o");
> -            virCommandAddArgFormat(cmd, "backing_fmt=%s%s", backingType,
> -                                   do_encryption ? ",encryption=on" : "");
> +            options = virStorageQemuImgOptionsStr(vol);
> +            virCommandAddArg(cmd, options);
>              virCommandAddArg(cmd, vol->target.path);
>              virCommandAddArgFormat(cmd, "%lluK", size_arg);
> +            VIR_FREE(options);
>              break;
>  
>          default:
> @@ -831,10 +878,13 @@ virStorageBackendCreateQemuImg(virConnectPtr conn,
>                               vol->target.path, NULL);
>          virCommandAddArgFormat(cmd, "%lluK", size_arg);
>  
> -        if (do_encryption) {
> -            if (imgformat == QEMU_IMG_BACKING_FORMAT_OPTIONS) {
> -                virCommandAddArgList(cmd, "-o", "encryption=on", NULL);
> -            } else {
> +        if (imgformat == QEMU_IMG_BACKING_FORMAT_OPTIONS) {
> +            virCommandAddArg(cmd, "-o");
> +            options = virStorageQemuImgOptionsStr(vol);
> +            virCommandAddArg(cmd, options);
> +            VIR_FREE(options);
> +        } else {
> +            if (do_encryption) {
>                  virCommandAddArg(cmd, "-e");
>              }
>          }
> -- 
> 1.7.10.1
> 
> --
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