Commit 719fc28c authored by Jeff Cody's avatar Jeff Cody Committed by Kevin Wolf
Browse files

block: fix external snapshot abort permission error 



In external_snapshot_abort(), we try to undo what was done in
external_snapshot_prepare() calling bdrv_replace_node() to swap the
nodes back.  However, we receive a permissions error as writers are
blocked on the old node, which is now the new node backing file.

An easy fix (initially suggested by Kevin Wolf) is to call
bdrv_set_backing_hd() on the new node, to set the backing node to NULL.

Signed-off-by: default avatarJeff Cody <jcody@redhat.com>
Reviewed-by: default avatarEric Blake <eblake@redhat.com>
Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
parent 272545cf

blockdev.c

+4 −0
Original line number Diff line number Diff line
@@ -1803,7 +1803,11 @@ static void external_snapshot_abort(BlkActionState *common) 
                             DO_UPCAST(ExternalSnapshotState, common, common);

    if (state->new_bs) {

        if (state->overlay_appended) {

            bdrv_ref(state->old_bs);   /* we can't let bdrv_set_backind_hd()

                                          close state->old_bs; we need it */

            bdrv_set_backing_hd(state->new_bs, NULL, &error_abort);

            bdrv_replace_node(state->new_bs, state->old_bs, &error_abort);

            bdrv_unref(state->old_bs); /* bdrv_replace_node() ref'ed old_bs */

        }

    }

}