G'day all,
This patch makes qemu-img properly consider the contents of the output
backing file when performing a convert operation. All things considered
it would also perform similar to rebase, where you could specify a
completely different backing file and it would just de-dup.
I've poked this in as an attachment as apparently my last attempt at an
in-line patch munged the formatting.
Comments, pokes or flames welcome.
Regards,
Brad
diff --git a/qemu-img.c b/qemu-img.c
index d9c2c12..02455af 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -571,11 +571,12 @@ static int img_convert(int argc, char **argv)
int progress = 0;
const char *fmt, *out_fmt, *out_baseimg, *out_filename;
BlockDriver *drv, *proto_drv;
- BlockDriverState **bs = NULL, *out_bs = NULL;
+ BlockDriverState **bs = NULL, *out_bs = NULL, *out_bf = NULL;
int64_t total_sectors, nb_sectors, sector_num, bs_offset;
uint64_t bs_sectors;
uint8_t * buf = NULL;
const uint8_t *buf1;
+ uint8_t * buf3 = NULL;
BlockDriverInfo bdi;
QEMUOptionParameter *param = NULL, *create_options = NULL;
QEMUOptionParameter *out_baseimg_param;
@@ -719,6 +720,16 @@ static int img_convert(int argc, char **argv)
out_baseimg_param = get_option_parameter(param, BLOCK_OPT_BACKING_FILE);
if (out_baseimg_param) {
out_baseimg = out_baseimg_param->value.s;
+
+ /* out_baseimg_parm != NULL even if there is no base img specified! */
+ if (out_baseimg) {
+ out_bf = bdrv_new_open(out_baseimg, NULL, BDRV_O_FLAGS);
+ if (!out_bf) {
+ error_report("Could not open backing file '%s'", out_baseimg);
+ ret = -1;
+ goto out;
+ }
+ }
}
/* Check if compression is supported */
@@ -767,6 +778,9 @@ static int img_convert(int argc, char **argv)
bs_offset = 0;
bdrv_get_geometry(bs[0], &bs_sectors);
buf = qemu_malloc(IO_BUF_SIZE);
+ if (out_baseimg) {
+ buf3 = qemu_malloc(IO_BUF_SIZE);
+ }
if (compress) {
ret = bdrv_get_info(out_bs, &bdi);
@@ -889,8 +903,15 @@ static int img_convert(int argc, char **argv)
are present in both the output's and input's base images (no
need to copy them). */
if (out_baseimg) {
- if (!bdrv_is_allocated(bs[bs_i], sector_num - bs_offset,
- n, &n1)) {
+ if (bdrv_read(bs[bs_i], sector_num - bs_offset, buf, n) <
0) {
+ error_report("error while reading input file");
+ goto out;
+ }
+ if (bdrv_read(out_bf, sector_num - bs_offset, buf3, n) <
0) {
+ error_report("error while reading backing file");
+ goto out;
+ }
+ if (!compare_sectors(buf, buf3, n, &n1)) {
sector_num += n1;
continue;
}
@@ -939,9 +960,13 @@ out:
free_option_parameters(create_options);
free_option_parameters(param);
qemu_free(buf);
+ qemu_free(buf3);
if (out_bs) {
bdrv_delete(out_bs);
}
+ if (out_bf) {
+ bdrv_delete(out_bf);
+ }
if (bs) {
for (bs_i = 0; bs_i < bs_n; bs_i++) {
if (bs[bs_i]) {
