diff --git a/fs/xfs/libxfs/xfs_inode_fork.h b/fs/xfs/libxfs/xfs_inode_fork.h
index c8f279edc5c1ff307d982f8e60d881fdb08b41a5..9e2137cd73724b965c4dca278ec3114d8a13b632 100644
--- a/fs/xfs/libxfs/xfs_inode_fork.h
+++ b/fs/xfs/libxfs/xfs_inode_fork.h
@@ -88,6 +88,13 @@ struct xfs_ifork {
  */
 #define XFS_IEXT_REFLINK_END_COW_CNT	(2)
 
+/*
+ * 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.
  */
diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
index 202d6af3e503c8b5351fdcfb943b1a37082e8a22..df004890c2a30084ed537a5e5167d44088a369b7 100644
--- a/fs/xfs/xfs_bmap_util.c
+++ b/fs/xfs/xfs_bmap_util.c
@@ -1367,6 +1367,22 @@ 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);