Add nilfs_sufile_trim_fs(), which takes an fstrim_range structure and
calls blkdev_issue_discard for every clean segment in the specified
range.  The range is truncated to file system block boundaries.
Signed-off-by: NAndreas Rohner <andreas.rohner@gmx.net>
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>