@@ -102,6 +102,13 @@ struct xfs_ifork {
#define XFS_IEXT_REFLINK_REMAP_CNT(smap_real, dmap_written) \
(((smap_real) ? 1 : 0) + ((dmap_written) ? 1 : 0))
+/*
+ * Removing an initial range of source/donor file's extent and adding a new
+ * extent (from donor/source file) in its place will cause extent count to
+ * increase by 1.
+ */
+#define XFS_IEXT_SWAP_RMAP_CNT (1)
+
/*
* Fork handling.
*/
@@ -1407,6 +1407,22 @@ xfs_swap_extent_rmap(
irec.br_blockcount);
trace_xfs_swap_extent_rmap_remap_piece(tip, &uirec);
+ if (xfs_bmap_is_real_extent(&uirec)) {
+ error = xfs_iext_count_may_overflow(ip,
+ XFS_DATA_FORK,
+ XFS_IEXT_SWAP_RMAP_CNT);
+ if (error)
+ goto out;
+ }
+
+ if (xfs_bmap_is_real_extent(&irec)) {
+ error = xfs_iext_count_may_overflow(tip,
+ XFS_DATA_FORK,
+ XFS_IEXT_SWAP_RMAP_CNT);
+ if (error)
+ goto out;
+ }
+
/* Remove the mapping from the donor file. */
xfs_bmap_unmap_extent(tp, tip, &uirec);