- if (ebno == NULLAGBLOCK) {
- /* No shared blocks at all. */
- return 0;
- } else if (agbno == ebno) {
- /*
- * Shared extent at (agbno, elen). Shrink the reported
- * extent length and prepare to move the start of map[i]
- * to agbno+elen, with the aim of (re)formatting the new
- * map[i] the next time through the inner loop.
- */
- out->bmv_length = XFS_FSB_TO_BB(mp, elen);
- out->bmv_oflags |= BMV_OF_SHARED;
- if (elen != map->br_blockcount) {
- *next_map = *map;
- next_map->br_startblock += elen;
- next_map->br_startoff += elen;
- next_map->br_blockcount -= elen;
- }
- map->br_blockcount -= elen;
- } else {
- /*
- * There's an unshared extent (agbno, ebno - agbno)
- * followed by shared extent at (ebno, elen). Shrink
- * the reported extent length to cover only the unshared
- * extent and prepare to move up the start of map[i] to
- * ebno, with the aim of (re)formatting the new map[i]
- * the next time through the inner loop.
- */
- *next_map = *map;
- nlen = ebno - agbno;
- out->bmv_length = XFS_FSB_TO_BB(mp, nlen);
- next_map->br_startblock += nlen;
- next_map->br_startoff += nlen;
- next_map->br_blockcount -= nlen;
- map->br_blockcount -= nlen;
- }