Index: sys/fs/ext2fs/ext2_bmap.c
===================================================================
--- sys/fs/ext2fs/ext2_bmap.c
+++ sys/fs/ext2fs/ext2_bmap.c
@@ -147,12 +147,12 @@
  * which they point.  Triple indirect blocks are addressed by one less than
  * the address of the first double indirect block to which they point.
  *
- * ext2_bmaparray does the bmap conversion, and if requested returns the
- * array of logical blocks which must be traversed to get to a block.
- * Each entry contains the offset into that block that gets you to the
- * next block and the disk address of the block (if it is assigned).
+ * This function maps the logical block number bn to a physical block number,
+ * returned in bnp.  If runb and runp are specified, they return a count
+ * of blocks before and after *bnp that are contiguous on disk, respectively.
+ * That is, the logical blocks in the range [bn - *runb, bn + *runp] map to
+ * [*bnp - *runb, *bnp + *runp].
  */
-
 int
 ext2_bmaparray(struct vnode *vp, daddr_t bn, daddr_t *bnp, int *runp, int *runb)
 {
Index: sys/ufs/ufs/ufs_bmap.c
===================================================================
--- sys/ufs/ufs/ufs_bmap.c
+++ sys/ufs/ufs/ufs_bmap.c
@@ -98,12 +98,15 @@
  * which they point.  Triple indirect blocks are addressed by one less than
  * the address of the first double indirect block to which they point.
  *
- * ufs_bmaparray does the bmap conversion, and if requested returns the
- * array of logical blocks which must be traversed to get to a block.
- * Each entry contains the offset into that block that gets you to the
- * next block and the disk address of the block (if it is assigned).
+ * This function maps the logical block number bn to a physical block number,
+ * returned in bnp.  The nbp-parameter is non-NULL when the mapping is for a
+ * block that contains data, one of an external data block, a direct block, or
+ * the final block in a chain of indirect blocks.  If mapping an extended
+ * attribute block, nbp must point to a buffer for that block.  If runb and
+ * runp are specified, they return a count of blocks before and after *bnp
+ * that are contiguous on disk, respectively.  That is, the logical blocks
+ * in the range [bn - *runb, bn + *runp] map to [*bnp - *runb, *bnp + *runp].
  */
-
 int
 ufs_bmaparray(vp, bn, bnp, nbp, runp, runb)
 	struct vnode *vp;