The qemu-img create command should check the backing format to ensure only image files with valid backing formats are created. By checking in qemu-img.c we can print a useful error message.
Signed-off-by: Stefan Hajnoczi <stefa...@linux.vnet.ibm.com> --- qemu-img.c | 22 ++++++++++++---------- 1 files changed, 12 insertions(+), 10 deletions(-) diff --git a/qemu-img.c b/qemu-img.c index 23bb7dc..b10f363 100644 --- a/qemu-img.c +++ b/qemu-img.c @@ -300,6 +300,7 @@ static int img_create(int argc, char **argv) const char *base_filename = NULL; BlockDriver *drv, *proto_drv; QEMUOptionParameter *param = NULL, *create_options = NULL; + QEMUOptionParameter *backing_fmt = NULL; char *options = NULL; flags = 0; @@ -390,14 +391,22 @@ static int img_create(int argc, char **argv) goto out; } + backing_fmt = get_option_parameter(param, BLOCK_OPT_BACKING_FMT); + if (backing_fmt && backing_fmt->value.s) { + if (!bdrv_find_format(backing_fmt->value.s)) { + error("Unknown backing file format '%s'", + backing_fmt->value.s); + ret = -1; + goto out; + } + } + // The size for the image must always be specified, with one exception: // If we are using a backing file, we can obtain the size from there if (get_option_parameter(param, BLOCK_OPT_SIZE)->value.n == -1) { QEMUOptionParameter *backing_file = get_option_parameter(param, BLOCK_OPT_BACKING_FILE); - QEMUOptionParameter *backing_fmt = - get_option_parameter(param, BLOCK_OPT_BACKING_FMT); if (backing_file && backing_file->value.s) { BlockDriverState *bs; @@ -406,14 +415,7 @@ static int img_create(int argc, char **argv) char buf[32]; if (backing_fmt && backing_fmt->value.s) { - if (bdrv_find_format(backing_fmt->value.s)) { - fmt = backing_fmt->value.s; - } else { - error("Unknown backing file format '%s'", - backing_fmt->value.s); - ret = -1; - goto out; - } + fmt = backing_fmt->value.s; } bs = bdrv_new_open(backing_file->value.s, fmt, BDRV_O_FLAGS); -- 1.7.2.3