Commit dcc98687 authored by Kevin Wolf's avatar Kevin Wolf
Browse files

qcow2: Creating images with external data file 



This adds a .bdrv_create option to use an external data file.

Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
parent 0e8c08be

block/qcow2.c

+26 −0
Original line number Diff line number Diff line
@@ -2880,6 +2880,7 @@ qcow2_co_create(BlockdevCreateOptions *create_options, Error **errp) 
     */

    BlockBackend *blk = NULL;

    BlockDriverState *bs = NULL;

    BlockDriverState *data_bs = NULL;

    QCowHeader *header;

    size_t cluster_size;

    int version;
@@ -2976,6 +2977,20 @@ qcow2_co_create(BlockdevCreateOptions *create_options, Error **errp) 
    }

    refcount_order = ctz32(qcow2_opts->refcount_bits);



    if (qcow2_opts->data_file) {

        if (version < 3) {

            error_setg(errp, "External data files are only supported with "

                       "compatibility level 1.1 and above (use version=v3 or "

                       "greater)");

            ret = -EINVAL;

            goto out;

        }

        data_bs = bdrv_open_blockdev_ref(qcow2_opts->data_file, errp);

        if (bs == NULL) {

            ret = -EIO;

            goto out;

        }

    }



    /* Create BlockBackend to write to the image */

    blk = blk_new(BLK_PERM_WRITE | BLK_PERM_RESIZE, BLK_PERM_ALL);
@@ -3014,6 +3029,10 @@ qcow2_co_create(BlockdevCreateOptions *create_options, Error **errp) 
        header->compatible_features |=

            cpu_to_be64(QCOW2_COMPAT_LAZY_REFCOUNTS);

    }

    if (data_bs) {

        header->incompatible_features |=

            cpu_to_be64(QCOW2_INCOMPAT_DATA_FILE);

    }



    ret = blk_pwrite(blk, 0, header, cluster_size, 0);

    g_free(header);
@@ -3044,6 +3063,9 @@ qcow2_co_create(BlockdevCreateOptions *create_options, Error **errp) 
    options = qdict_new();

    qdict_put_str(options, "driver", "qcow2");

    qdict_put_str(options, "file", bs->node_name);

    if (data_bs) {

        qdict_put_str(options, "data-file", data_bs->node_name);

    }

    blk = blk_new_open(NULL, NULL, options,

                       BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_NO_FLUSH,

                       &local_err);
@@ -3116,6 +3138,9 @@ qcow2_co_create(BlockdevCreateOptions *create_options, Error **errp) 
    options = qdict_new();

    qdict_put_str(options, "driver", "qcow2");

    qdict_put_str(options, "file", bs->node_name);

    if (data_bs) {

        qdict_put_str(options, "data-file", data_bs->node_name);

    }

    blk = blk_new_open(NULL, NULL, options,

                       BDRV_O_RDWR | BDRV_O_NO_BACKING | BDRV_O_NO_IO,

                       &local_err);
@@ -3129,6 +3154,7 @@ qcow2_co_create(BlockdevCreateOptions *create_options, Error **errp) 
out:

    blk_unref(blk);

    bdrv_unref(bs);

    bdrv_unref(data_bs);

    return ret;

}

include/block/block_int.h

+1 −0
Original line number Diff line number Diff line
@@ -56,6 +56,7 @@ 
#define BLOCK_OPT_NOCOW             "nocow"

#define BLOCK_OPT_OBJECT_SIZE       "object_size"

#define BLOCK_OPT_REFCOUNT_BITS     "refcount_bits"

#define BLOCK_OPT_DATA_FILE         "data_file"



#define BLOCK_PROBE_BUF_SIZE        512

qapi/block-core.json

+4 −0
Original line number Diff line number Diff line
@@ -4135,6 +4135,9 @@ 
# Driver specific image creation options for qcow2.

#

# @file             Node to create the image format on

# @data-file        Node to use as an external data file in which all guest

#                   data is stored so that only metadata remains in the qcow2

#                   file (since: 4.0)

# @size             Size of the virtual disk in bytes

# @version          Compatibility level (default: v3)

# @backing-file     File name of the backing file if a backing file
@@ -4150,6 +4153,7 @@ 
##

{ 'struct': 'BlockdevCreateOptionsQcow2',

  'data': { 'file':             'BlockdevRef',

            '*data-file':       'BlockdevRef',

            'size':             'size',

            '*version':         'BlockdevQcow2Version',

            '*backing-file':    'str',