xfs: repair refcount btreesrepair-ag-btrees_2021-12-15

Reconstruct the refcount data from the rmap btree.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>

1 files changed, 26 insertions, 0 deletions

diff --git a/fs/xfs/libxfs/xfs_btree.c b/fs/xfs/libxfs/xfs_btree.c
index 16dd3efabc11..3b5f95c954f3 100644
--- a/fs/xfs/libxfs/xfs_btree.c
+++ b/fs/xfs/libxfs/xfs_btree.c
@@ -5077,3 +5077,29 @@ xfs_btree_destroy_cur_caches(void)
 	xfs_rmapbt_destroy_cur_cache();
 	xfs_refcountbt_destroy_cur_cache();
 }
+
+/* Move the btree cursor before the first record. */
+int
+xfs_btree_goto_left_edge(
+	struct xfs_btree_cur	*cur)
+{
+	int			stat = 0;
+	int			error;
+
+	memset(&cur->bc_rec, 0, sizeof(cur->bc_rec));
+	error = xfs_btree_lookup(cur, XFS_LOOKUP_LE, &stat);
+	if (error)
+		return error;
+	if (!stat)
+		return 0;
+
+	error = xfs_btree_decrement(cur, 0, &stat);
+	if (error)
+		return error;
+	if (stat != 0) {
+		ASSERT(0);
+		return -EFSCORRUPTED;
+	}
+
+	return 0;
+}