Commit e54ee1b3 authored by Eric Blake's avatar Eric Blake Committed by Kevin Wolf
Browse files

block: Add support to warn on backing file change without format 



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: default avatarEric Blake <eblake@redhat.com>
Reviewed-by: default avatarPeter Krempa <pkrempa@redhat.com>
Reviewed-by: default avatarJán Tomko <jtomko@redhat.com>
Message-Id: <20200706203954.341758-10-eblake@redhat.com>
Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
parent b66ff2c2

block.c

+10 −3
Original line number Diff line number Diff line
@@ -1206,7 +1206,8 @@ 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");

    }
@@ -4680,8 +4681,8 @@ 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;
@@ -4695,6 +4696,12 @@ 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 {

block/qcow2.c

+1 −1
Original line number Diff line number Diff line
@@ -3627,7 +3627,7 @@ 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,

block/stream.c

+1 −1
Original line number Diff line number Diff line
@@ -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;

blockdev.c

+2 −1
Original line number Diff line number Diff line
@@ -3416,7 +3416,8 @@ 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'",

include/block/block.h

+2 −2
Original line number Diff line number Diff line
@@ -405,8 +405,8 @@ 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_make_empty(BdrvChild *c, Error **errp);

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);