diff --git a/block.c b/block.c index ef5af81f66..ab354ba82a 100644 --- a/block.c +++ b/block.c @@ -981,6 +981,21 @@ static void bdrv_backing_options(int *child_flags, QDict *child_options, *child_flags = flags; } +static int bdrv_backing_update_filename(BdrvChild *c, BlockDriverState *base, + const char *filename, Error **errp) +{ + BlockDriverState *parent = c->opaque; + int ret; + + ret = bdrv_change_backing_file(parent, filename, + base->drv ? base->drv->format_name : ""); + if (ret < 0) { + error_setg_errno(errp, ret, "Could not update backing file link"); + } + + return ret; +} + const BdrvChildRole child_backing = { .get_parent_desc = bdrv_child_get_parent_desc, .attach = bdrv_backing_attach, @@ -989,6 +1004,7 @@ const BdrvChildRole child_backing = { .drained_begin = bdrv_child_cb_drained_begin, .drained_end = bdrv_child_cb_drained_end, .inactivate = bdrv_child_cb_inactivate, + .update_filename = bdrv_backing_update_filename, }; static int bdrv_open_flags(BlockDriverState *bs, int flags) @@ -3470,6 +3486,8 @@ int bdrv_drop_intermediate(BlockDriverState *active, BlockDriverState *top, Error *local_err = NULL; int ret = -EIO; + bdrv_ref(top); + if (!top->drv || !base->drv) { goto exit; } @@ -3494,11 +3512,15 @@ int bdrv_drop_intermediate(BlockDriverState *active, BlockDriverState *top, } /* success - we can delete the intermediate states, and link top->base */ - backing_file_str = backing_file_str ? backing_file_str : base->filename; - ret = bdrv_change_backing_file(new_top_bs, backing_file_str, - base->drv ? base->drv->format_name : ""); - if (ret) { - goto exit; + if (new_top_bs->backing->role->update_filename) { + backing_file_str = backing_file_str ? backing_file_str : base->filename; + ret = new_top_bs->backing->role->update_filename(new_top_bs->backing, + base, backing_file_str, + &local_err); + if (ret < 0) { + bdrv_set_backing_hd(new_top_bs, top, &error_abort); + goto exit; + } } bdrv_set_backing_hd(new_top_bs, base, &local_err); @@ -3510,6 +3532,7 @@ int bdrv_drop_intermediate(BlockDriverState *active, BlockDriverState *top, ret = 0; exit: + bdrv_unref(top); return ret; } diff --git a/include/block/block_int.h b/include/block/block_int.h index 79366b94b5..7e8a206239 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -544,6 +544,12 @@ struct BdrvChildRole { void (*attach)(BdrvChild *child); void (*detach)(BdrvChild *child); + + /* Notifies the parent that the filename of its child has changed (e.g. + * because the direct child was removed from the backing chain), so that it + * can update its reference. */ + int (*update_filename)(BdrvChild *child, BlockDriverState *new_base, + const char *filename, Error **errp); }; extern const BdrvChildRole child_file;