Commit 2b2c8c5d authored by Fam Zheng's avatar Fam Zheng Committed by Kevin Wolf
Browse files

VMDK: read/write compressed extent 



Add support for reading/writing compressed extent.

Signed-off-by: default avatarFam Zheng <famcool@gmail.com>
Reviewed-by: default avatarStefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
parent 432bb170

block/vmdk.c

+100 −11
Original line number Diff line number Diff line
@@ -775,10 +775,12 @@ static int get_cluster_offset(BlockDriverState *bs, 


        /* Avoid the L2 tables update for the images that have snapshots. */

        *cluster_offset = bdrv_getlength(extent->file);

        if (!extent->compressed) {

            bdrv_truncate(

                extent->file,

                *cluster_offset + (extent->cluster_sectors << 9)

            );

        }



        *cluster_offset >>= 9;

        tmp = cpu_to_le32(*cluster_offset);
@@ -854,9 +856,28 @@ static int vmdk_write_extent(VmdkExtent *extent, int64_t cluster_offset, 
                            int nb_sectors, int64_t sector_num)

{

    int ret;

    VmdkGrainMarker *data = NULL;

    uLongf buf_len;

    const uint8_t *write_buf = buf;

    int write_len = nb_sectors * 512;



    if (extent->compressed) {

        if (!extent->has_marker) {

            ret = -EINVAL;

            goto out;

        }

        buf_len = (extent->cluster_sectors << 9) * 2;

        data = g_malloc(buf_len + sizeof(VmdkGrainMarker));

        if (compress(data->data, &buf_len, buf, nb_sectors << 9) != Z_OK ||

                buf_len == 0) {

            ret = -EINVAL;

            goto out;

        }

        data->lba = sector_num;

        data->size = buf_len;

        write_buf = (uint8_t *)data;

        write_len = buf_len + sizeof(VmdkGrainMarker);

    }

    ret = bdrv_pwrite(extent->file,

                        cluster_offset + offset_in_cluster,

                        write_buf,
@@ -867,6 +888,7 @@ static int vmdk_write_extent(VmdkExtent *extent, int64_t cluster_offset, 
    }

    ret = 0;

 out:

    g_free(data);

    return ret;

}
@@ -875,7 +897,15 @@ static int vmdk_read_extent(VmdkExtent *extent, int64_t cluster_offset, 
                            int nb_sectors)

{

    int ret;

    int cluster_bytes, buf_bytes;

    uint8_t *cluster_buf, *compressed_data;

    uint8_t *uncomp_buf;

    uint32_t data_len;

    VmdkGrainMarker *marker;

    uLongf buf_len;





    if (!extent->compressed) {

        ret = bdrv_pread(extent->file,

                          cluster_offset + offset_in_cluster,

                          buf, nb_sectors * 512);
@@ -885,6 +915,48 @@ static int vmdk_read_extent(VmdkExtent *extent, int64_t cluster_offset, 
            return -EIO;

        }

    }

    cluster_bytes = extent->cluster_sectors * 512;

    /* Read two clusters in case GrainMarker + compressed data > one cluster */

    buf_bytes = cluster_bytes * 2;

    cluster_buf = g_malloc(buf_bytes);

    uncomp_buf = g_malloc(cluster_bytes);

    ret = bdrv_pread(extent->file,

                cluster_offset,

                cluster_buf, buf_bytes);

    if (ret < 0) {

        goto out;

    }

    compressed_data = cluster_buf;

    buf_len = cluster_bytes;

    data_len = cluster_bytes;

    if (extent->has_marker) {

        marker = (VmdkGrainMarker *)cluster_buf;

        compressed_data = marker->data;

        data_len = le32_to_cpu(marker->size);

    }

    if (!data_len || data_len > buf_bytes) {

        ret = -EINVAL;

        goto out;

    }

    ret = uncompress(uncomp_buf, &buf_len, compressed_data, data_len);

    if (ret != Z_OK) {

        ret = -EINVAL;

        goto out;



    }

    if (offset_in_cluster < 0 ||

            offset_in_cluster + nb_sectors * 512 > buf_len) {

        ret = -EINVAL;

        goto out;

    }

    memcpy(buf, uncomp_buf + offset_in_cluster, nb_sectors * 512);

    ret = 0;



 out:

    g_free(uncomp_buf);

    g_free(cluster_buf);

    return ret;

}



static int vmdk_read(BlockDriverState *bs, int64_t sector_num,

                    uint8_t *buf, int nb_sectors)
@@ -959,12 +1031,29 @@ static int vmdk_write(BlockDriverState *bs, int64_t sector_num, 
        if (!extent) {

            return -EIO;

        }

        ret = get_cluster_offset(

                                bs,

                                extent,

                                &m_data,

                                sector_num << 9, !extent->compressed,

                                &cluster_offset);

        if (extent->compressed) {

            if (ret == 0) {

                /* Refuse write to allocated cluster for streamOptimized */

                fprintf(stderr,

                        "VMDK: can't write to allocated cluster"

                        " for streamOptimized\n");

                return -EIO;

            } else {

                /* allocate */

                ret = get_cluster_offset(

                                        bs,

                                        extent,

                                        &m_data,

                                        sector_num << 9, 1,

                                        &cluster_offset);

            }

        }

        if (ret) {

            return -EINVAL;

        }