diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c index 146c7dbcf04c..a916b8041705 100644 --- a/fs/btrfs/relocation.c +++ b/fs/btrfs/relocation.c @@ -1994,8 +1994,33 @@ struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans, cond_resched(); next = walk_up_backref(next, edges, &index); root = next->root; - BUG_ON(!root); - BUG_ON(!test_bit(BTRFS_ROOT_SHAREABLE, &root->state)); + + /* + * If there is no root, then our references for this block are + * incomplete, as we should be able to walk all the way up to a + * block that is owned by a root. + * + * This path is only for SHAREABLE roots, so if we come upon a + * non-SHAREABLE root then we have backrefs that resolve + * improperly. + * + * Both of these cases indicate file system corruption, or a bug + * in the backref walking code. + */ + if (!root) { + ASSERT(0); + btrfs_err(trans->fs_info, + "bytenr %llu doesn't have a backref path ending in a root", + node->bytenr); + return ERR_PTR(-EUCLEAN); + } + if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state)) { + ASSERT(0); + btrfs_err(trans->fs_info, + "bytenr %llu has multiple refs with one ending in a non-shareable root", + node->bytenr); + return ERR_PTR(-EUCLEAN); + } if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) { record_reloc_root_in_trans(trans, root); @@ -2006,8 +2031,22 @@ struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans, root = root->reloc_root; if (next->new_bytenr != root->node->start) { - BUG_ON(next->new_bytenr); - BUG_ON(!list_empty(&next->list)); + /* + * We just created the reloc root, so we shouldn't have + * ->new_bytenr set and this shouldn't be in the changed + * list. If it is then we have multiple roots pointing + * at the same bytenr which indicates corruption, or + * we've made a mistake in the backref walking code. + */ + ASSERT(next->new_bytenr == 0); + ASSERT(list_empty(&next->list)); + if (next->new_bytenr || !list_empty(&next->list)) { + btrfs_err(trans->fs_info, + "bytenr %llu possibly has multiple roots pointing at the same bytenr %llu", + node->bytenr, next->bytenr); + return ERR_PTR(-EUCLEAN); + } + next->new_bytenr = root->node->start; btrfs_put_root(next->root); next->root = btrfs_grab_root(root);