Commit 8ee79e70 authored by Kevin Wolf's avatar Kevin Wolf
Browse files

block: Catch backing files assigned to non-COW drivers 



Since we parse backing.* options to add a backing file from the command
line when the driver didn't assign one, it has been possible to have a
backing file for e.g. raw images (it just was never accessed).

This is obvious nonsense and should be rejected.

Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
Reviewed-by: default avatarEric Blake <eblake@redhat.com>
parent 76c591b0

block.c

+7 −0
Original line number Diff line number Diff line
@@ -1192,6 +1192,13 @@ int bdrv_open_backing_file(BlockDriverState *bs, QDict *options, Error **errp) 
        bdrv_get_full_backing_filename(bs, backing_filename, PATH_MAX);

    }



    if (!bs->drv || !bs->drv->supports_backing) {

        ret = -EINVAL;

        error_setg(errp, "Driver doesn't support backing files");

        QDECREF(options);

        goto free_exit;

    }



    backing_hd = bdrv_new("", errp);



    if (bs->backing_format[0] != '\0') {

block/cow.c

+1 −0
Original line number Diff line number Diff line
@@ -414,6 +414,7 @@ static BlockDriver bdrv_cow = { 
    .bdrv_close     = cow_close,

    .bdrv_create    = cow_create,

    .bdrv_has_zero_init     = bdrv_has_zero_init_1,

    .supports_backing       = true,



    .bdrv_read              = cow_co_read,

    .bdrv_write             = cow_co_write,

block/qcow.c

+1 −0
Original line number Diff line number Diff line
@@ -941,6 +941,7 @@ static BlockDriver bdrv_qcow = { 
    .bdrv_reopen_prepare    = qcow_reopen_prepare,

    .bdrv_create            = qcow_create,

    .bdrv_has_zero_init     = bdrv_has_zero_init_1,

    .supports_backing       = true,



    .bdrv_co_readv          = qcow_co_readv,

    .bdrv_co_writev         = qcow_co_writev,

block/qcow2.c

+1 −0
Original line number Diff line number Diff line
@@ -2418,6 +2418,7 @@ static BlockDriver bdrv_qcow2 = { 
    .bdrv_save_vmstate    = qcow2_save_vmstate,

    .bdrv_load_vmstate    = qcow2_load_vmstate,



    .supports_backing           = true,

    .bdrv_change_backing_file   = qcow2_change_backing_file,



    .bdrv_refresh_limits        = qcow2_refresh_limits,

block/qed.c

+1 −0
Original line number Diff line number Diff line
@@ -1652,6 +1652,7 @@ static BlockDriver bdrv_qed = { 
    .format_name              = "qed",

    .instance_size            = sizeof(BDRVQEDState),

    .create_opts              = &qed_create_opts,

    .supports_backing         = true,



    .bdrv_probe               = bdrv_qed_probe,

    .bdrv_rebind              = bdrv_qed_rebind,