block: Introduce BdrvChildRole.update_filename
There is no good reason for bdrv_drop_intermediate() to know the active layer above the subchain it is operating on - even more so, because the assumption that there is a single active layer above it is not generally true. In order to prepare removal of the active parameter, use a BdrvChildRole callback to update the backing file string in the overlay image instead of directly calling bdrv_change_backing_file(). Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
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09d653e617
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6858eba09e
29
block.c
29
block.c
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@ -981,6 +981,21 @@ static void bdrv_backing_options(int *child_flags, QDict *child_options,
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*child_flags = flags;
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*child_flags = flags;
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}
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}
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static int bdrv_backing_update_filename(BdrvChild *c, BlockDriverState *base,
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const char *filename, Error **errp)
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{
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BlockDriverState *parent = c->opaque;
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int ret;
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ret = bdrv_change_backing_file(parent, filename,
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base->drv ? base->drv->format_name : "");
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if (ret < 0) {
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error_setg_errno(errp, ret, "Could not update backing file link");
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}
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return ret;
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}
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const BdrvChildRole child_backing = {
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const BdrvChildRole child_backing = {
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.get_parent_desc = bdrv_child_get_parent_desc,
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.get_parent_desc = bdrv_child_get_parent_desc,
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.attach = bdrv_backing_attach,
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.attach = bdrv_backing_attach,
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@ -989,6 +1004,7 @@ const BdrvChildRole child_backing = {
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.drained_begin = bdrv_child_cb_drained_begin,
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.drained_begin = bdrv_child_cb_drained_begin,
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.drained_end = bdrv_child_cb_drained_end,
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.drained_end = bdrv_child_cb_drained_end,
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.inactivate = bdrv_child_cb_inactivate,
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.inactivate = bdrv_child_cb_inactivate,
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.update_filename = bdrv_backing_update_filename,
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};
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};
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static int bdrv_open_flags(BlockDriverState *bs, int flags)
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static int bdrv_open_flags(BlockDriverState *bs, int flags)
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@ -3470,6 +3486,8 @@ int bdrv_drop_intermediate(BlockDriverState *active, BlockDriverState *top,
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Error *local_err = NULL;
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Error *local_err = NULL;
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int ret = -EIO;
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int ret = -EIO;
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bdrv_ref(top);
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if (!top->drv || !base->drv) {
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if (!top->drv || !base->drv) {
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goto exit;
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goto exit;
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}
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}
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@ -3494,12 +3512,16 @@ int bdrv_drop_intermediate(BlockDriverState *active, BlockDriverState *top,
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}
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}
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/* success - we can delete the intermediate states, and link top->base */
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/* success - we can delete the intermediate states, and link top->base */
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if (new_top_bs->backing->role->update_filename) {
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backing_file_str = backing_file_str ? backing_file_str : base->filename;
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backing_file_str = backing_file_str ? backing_file_str : base->filename;
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ret = bdrv_change_backing_file(new_top_bs, backing_file_str,
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ret = new_top_bs->backing->role->update_filename(new_top_bs->backing,
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base->drv ? base->drv->format_name : "");
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base, backing_file_str,
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if (ret) {
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&local_err);
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if (ret < 0) {
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bdrv_set_backing_hd(new_top_bs, top, &error_abort);
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goto exit;
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goto exit;
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}
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}
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}
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bdrv_set_backing_hd(new_top_bs, base, &local_err);
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bdrv_set_backing_hd(new_top_bs, base, &local_err);
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if (local_err) {
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if (local_err) {
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@ -3510,6 +3532,7 @@ int bdrv_drop_intermediate(BlockDriverState *active, BlockDriverState *top,
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ret = 0;
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ret = 0;
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exit:
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exit:
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bdrv_unref(top);
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return ret;
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return ret;
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}
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}
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@ -544,6 +544,12 @@ struct BdrvChildRole {
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void (*attach)(BdrvChild *child);
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void (*attach)(BdrvChild *child);
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void (*detach)(BdrvChild *child);
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void (*detach)(BdrvChild *child);
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/* Notifies the parent that the filename of its child has changed (e.g.
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* because the direct child was removed from the backing chain), so that it
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* can update its reference. */
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int (*update_filename)(BdrvChild *child, BlockDriverState *new_base,
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const char *filename, Error **errp);
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};
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};
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extern const BdrvChildRole child_file;
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extern const BdrvChildRole child_file;
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