5:23 a.m.
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 <eblake(a)redhat.com>
---
block.c | 14 +++++++++++---
block/qcow2.c | 2 +-
block/stream.c | 2 +-
blockdev.c | 3 ++-
include/block/block.h | 4 ++--
qemu-img.c | 4 ++--
6 files changed, 19 insertions(+), 10 deletions(-)
diff --git a/block.c b/block.c
index 308a91c96bde..695decbfd7b7 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");
}
@@ -4508,8 +4509,8 @@ 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;
@@ -4523,6 +4524,13 @@ int bdrv_change_backing_file(BlockDriverState *bs,
return -EINVAL;
}
+ if (warn && backing_file && !backing_fmt &&
+ !strstart(backing_file, "json:", NULL)) {
+ 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, &local_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/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/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, NULL);
+ ret = bdrv_change_backing_file(bs, NULL, NULL, false);
}
if (ret == -ENOSPC) {
--
2.24.1