For now, this is a mechanical addition; all callers pass false. But
the next patch will use it to improve 'qemu-img rebase -u' when
selecting a backing file with no format.
Signed-off-by: Eric Blake
---
include/block/block.h | 4 ++--
block.c | 13 ++---
block/qcow2.c | 2 +-
block/stream.c| 2 +-
blockdev.c| 3 ++-
qemu-img.c| 4 ++--
6 files changed, 18 insertions(+), 10 deletions(-)
diff --git a/include/block/block.h b/include/block/block.h
index cd6b5b95aad2..8b1dd94f7629 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -350,8 +350,8 @@ BlockMeasureInfo *bdrv_measure(BlockDriver *drv, QemuOpts
*opts,
void bdrv_get_geometry(BlockDriverState *bs, uint64_t *nb_sectors_ptr);
void bdrv_refresh_limits(BlockDriverState *bs, Error **errp);
int bdrv_commit(BlockDriverState *bs);
-int bdrv_change_backing_file(BlockDriverState *bs,
-const char *backing_file, const char *backing_fmt);
+int bdrv_change_backing_file(BlockDriverState *bs, const char *backing_file,
+ const char *backing_fmt, bool warn);
void bdrv_register(BlockDriver *bdrv);
int bdrv_drop_intermediate(BlockDriverState *top, BlockDriverState *base,
const char *backing_file_str);
diff --git a/block.c b/block.c
index 1bdb9c679d77..10c2a34e7c00 100644
--- a/block.c
+++ b/block.c
@@ -1290,7 +1290,8 @@ static int bdrv_backing_update_filename(BdrvChild *c,
BlockDriverState *base,
}
ret = bdrv_change_backing_file(parent, filename,
- base->drv ? base->drv->format_name : "");
+ base->drv ? base->drv->format_name : "",
+ false);
if (ret < 0) {
error_setg_errno(errp, -ret, "Could not update backing file link");
}
@@ -4505,8 +4506,8 @@ int bdrv_check(BlockDriverState *bs,
*image file header
* -ENOTSUP - format driver doesn't support changing the backing file
*/
-int bdrv_change_backing_file(BlockDriverState *bs,
-const char *backing_file, const char *backing_fmt)
+int bdrv_change_backing_file(BlockDriverState *bs, const char *backing_file,
+ const char *backing_fmt, bool warn)
{
BlockDriver *drv = bs->drv;
int ret;
@@ -4520,6 +4521,12 @@ int bdrv_change_backing_file(BlockDriverState *bs,
return -EINVAL;
}
+if (warn && backing_file && !backing_fmt) {
+warn_report("Deprecated use of backing file without explicit "
+"backing format, use of this image requires "
+"potentially unsafe format probing");
+}
+
if (drv->bdrv_change_backing_file != NULL) {
ret = drv->bdrv_change_backing_file(bs, backing_file, backing_fmt);
} else {
diff --git a/block/qcow2.c b/block/qcow2.c
index 3c754f616bf8..05a2973a3086 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -3502,7 +3502,7 @@ qcow2_co_create(BlockdevCreateOptions *create_options,
Error **errp)
}
ret = bdrv_change_backing_file(blk_bs(blk), qcow2_opts->backing_file,
- backing_format);
+ backing_format, false);
if (ret < 0) {
error_setg_errno(errp, -ret, "Could not assign backing file '%s' "
"with format '%s'", qcow2_opts->backing_file,
diff --git a/block/stream.c b/block/stream.c
index 5562ccbf577a..7c4d8ee0bcf1 100644
--- a/block/stream.c
+++ b/block/stream.c
@@ -78,7 +78,7 @@ static int stream_prepare(Job *job)
}
}
bdrv_set_backing_hd(bs, base, _err);
-ret = bdrv_change_backing_file(bs, base_id, base_fmt);
+ret = bdrv_change_backing_file(bs, base_id, base_fmt, false);
if (local_err) {
error_report_err(local_err);
return -EPERM;
diff --git a/blockdev.c b/blockdev.c
index 011dcfec2770..c88f27941d46 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -4299,7 +4299,8 @@ void qmp_change_backing_file(const char *device,
}
ret = bdrv_change_backing_file(image_bs, backing_file,
- image_bs->drv ? image_bs->drv->format_name :
"");
+ image_bs->drv ? image_bs->drv->format_name
: "",
+ false);
if (ret < 0) {
error_setg_errno(errp, -ret, "Could not change backing file to '%s'",
diff --git a/qemu-img.c b/qemu-img.c
index 804630a368d6..b9375427404d 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -3637,9 +3637,9 @@ static int img_rebase(int argc, char **argv)
* doesn't change when we switch the backing file.
*/
if (out_baseimg && *out_baseimg) {
-ret = bdrv_change_backing_file(bs, out_baseimg, out_basefmt);
+ret = bdrv_change_backing_file(bs, out_baseimg, out_basefmt, false);
} else {
-ret = bdrv_change_backing_file(bs, NULL,
