[libvirt] [PATCH 3/6] storage:dir: adapts .uploadVol .dowloadVol for ploop volume

[Nikolay Shirokovskiy]

On 17.02.2016 14:40, Olga Krishtal wrote:
> In case of ploop volume, target path of the volume is the path to the
> directory that contains image file named root.hds and DiskDescriptor.xml.
> While using uploadVol and downloadVol callbacks we need to open root.hds
> itself. To accomplish this goal we must change path from
> path/to/ploop directory to path/to/ploop/root.hds
> 
> In case of .uploadVol, we have to additionaly update DiskDescriptor.xml
> 
> Signed-off-by: Olga Krishtal <okrishtal at virtuozzo.com>
> ---
>  src/storage/storage_backend.c | 66 +++++++++++++++++++++++++++++++++++++++++--
>  1 file changed, 64 insertions(+), 2 deletions(-)
> 
> diff --git a/src/storage/storage_backend.c b/src/storage/storage_backend.c
> index 9f0e020..ac44fdf 100644
> --- a/src/storage/storage_backend.c
> +++ b/src/storage/storage_backend.c
> @@ -2023,12 +2023,63 @@ virStorageBackendVolUploadLocal(virConnectPtr conn ATTRIBUTE_UNUSED,
>                                  unsigned long long len,
>                                  unsigned int flags)
>  {
> +    char *path = NULL;
> +    char *target_path = vol->target.path;
> +    int ret;
> +    virCommandPtr cmd = NULL;
> +    char *create_tool = NULL;
> +
>      virCheckFlags(0, -1);
>  
>      /* Not using O_CREAT because the file is required to already exist at
>       * this point */
> -    return virFDStreamOpenBlockDevice(stream, vol->target.path,
> +    if (vol->target.format != VIR_STORAGE_FILE_PLOOP) {
> +        return virFDStreamOpenBlockDevice(stream, target_path,
>                                        offset, len, O_WRONLY);
> +    } else {
> +        if (virAsprintf(&path, "%s/root.hds", vol->target.path) < 0)
> +            return -1;
> +        target_path = path;
> +        ret = virFDStreamOpenBlockDevice(stream, target_path,
> +                                      offset, len, O_WRONLY);
> +        if (ret < 0) {
> +            goto cleanup;
> +        }
> +
> +        create_tool = virFindFileInPath("ploop");
> +        if (!create_tool) {
> +            virReportError(VIR_ERR_INTERNAL_ERROR,
> +                           "%s", _("unable to find ploop, please install "
> +                           "ploop tools"));
> +            ret = -1;
> +            goto cleanup;
> +        }
> +        cmd = virCommandNewArgList(create_tool, "restore-descriptor",
> +                                   vol->target.path, target_path, NULL);
> +        VIR_FREE(path);
> +        if (virAsprintf(&path, "%s/DiskDescriptor.xml",
> +                        vol->target.path) < 0) {
> +            ret = -1;
> +            goto cleanup;
> +        }
> +        if (virFileExists(path)) {
> +            if (virFileRemove(path, 0, 0) < 0) {
> +                ret = -1;
> +                virReportError(VIR_ERR_INTERNAL_ERROR, "%s", _("unable "
> +                            "to delete existing DiskDescriptor.xml"));
> +                goto cleanup;
> +            }
> +        }
> +        if (virCommandRun(cmd, NULL) < 0) {
> +            ret = -1;
> +            goto cleanup;
> +        }

Unfortunately we can't restore descriptor at this moment as wee only create stream here.
Later someone will write data into the stream and only after stream is closed
we can update our structures.

> +    }
> +
> + cleanup:
> +    VIR_FREE(cmd);
> +    VIR_FREE(path);
> +    return ret;
>  }
>  
>  int
> @@ -2040,10 +2091,21 @@ virStorageBackendVolDownloadLocal(virConnectPtr conn ATTRIBUTE_UNUSED,
>                                    unsigned long long len,
>                                    unsigned int flags)
>  {
> +    char *path = NULL;
> +    char *target_path = vol->target.path;
> +    int ret;
> +
>      virCheckFlags(0, -1);
> +    if (vol->target.format == VIR_STORAGE_FILE_PLOOP) {
> +        if (virAsprintf(&path, "%s/root.hds", vol->target.path) < 0)
> +            return -1;
> +        target_path = path;
> +    }
>  
> -    return virFDStreamOpenBlockDevice(stream, vol->target.path,
> +    ret = virFDStreamOpenBlockDevice(stream, target_path,
>                                        offset, len, O_RDONLY);
> +    VIR_FREE(path);
> +    return ret;
>  }
>  
>  
>