ocfs2: make ocfs2_adjust_resv_from_alloc simple.

When we allocate some bits from the reservation, we always
allocate from the r_start(see ocfs2_resmap_resv_bits).
So there should be no reason to check between r_start
and start. And I don't think we will change this behaviour
later by allocating from some bits after r_start.  Why not make
ocfs2_adjust_resv_from_alloc simple for now?

The only chance we have to adjust the reservation is when we haven't
reached the end. With this patch, the function is more readable.

Note:
btw, this patch also fixes an original bug in the function
which I haven't found before.
	if (end < ocfs2_resv_end(resv))
		rhs = end - ocfs2_resv_end(resv);
This code is of course buggy. ;)

Signed-off-by: Tao Ma <tao.ma@oracle.com>
Acked-by: Mark Fasheh <mfasheh@suse.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/fs/ocfs2/reservations.h b/fs/ocfs2/reservations.h
index 25b0c0e31e9..1e49cc29d06 100644
--- a/fs/ocfs2/reservations.h
+++ b/fs/ocfs2/reservations.h
@@ -149,7 +149,8 @@ int ocfs2_resmap_resv_bits(struct ocfs2_reservation_map *resmap,
  * reservation. But we must always call this function when bits are claimed.
  * Internally, the reservations code will use this information to mark the
  * reservations bitmap. If resv is passed, it's next allocation window will be
- * calculated.
+ * calculated. It also expects that 'cstart' is the same as we passed back
+ * from ocfs2_resmap_resv_bits().
  */
 void ocfs2_resmap_claimed_bits(struct ocfs2_reservation_map *resmap,
 			       struct ocfs2_alloc_reservation *resv,