The old -B option caused a backing file to be used for the converted image and to avoid copying clusters from the old backing file. When replaced with -obacking_file, qemu-img convert does assign the backing file to the new image, but it doesn't realize that it should avoid copying clusters from the backing file.
This patch checks the -o options for a backing_file and applies the same logic as for -B in this case. Signed-off-by: Kevin Wolf <kw...@redhat.com> --- qemu-img.c | 7 +++++++ 1 files changed, 7 insertions(+), 0 deletions(-) diff --git a/qemu-img.c b/qemu-img.c index d4a3b4e..2864cb8 100644 --- a/qemu-img.c +++ b/qemu-img.c @@ -645,6 +645,7 @@ static int img_convert(int argc, char **argv) const uint8_t *buf1; BlockDriverInfo bdi; QEMUOptionParameter *param = NULL, *create_options = NULL; + QEMUOptionParameter *out_baseimg_param; char *options = NULL; const char *snapshot_name = NULL; @@ -769,6 +770,12 @@ static int img_convert(int argc, char **argv) goto out; } + /* Get backing file name if -o backing_file was used */ + out_baseimg_param = get_option_parameter(param, BLOCK_OPT_BACKING_FILE); + if (out_baseimg_param) { + out_baseimg = out_baseimg_param->value.s; + } + /* Check if compression is supported */ if (flags & BLOCK_FLAG_COMPRESS) { QEMUOptionParameter *encryption = -- 1.7.2.3