xfs: refactor xfs_trans_reserve() interface

With the new xfs_trans_res structure has been introduced, the log
reservation size, log count as well as log flags are pre-initialized
at mount time.  So it's time to refine xfs_trans_reserve() interface
to be more neat.

Also, introduce a new helper M_RES() to return a pointer to the
mp->m_resv structure to simplify the input.

Signed-off-by: Jie Liu <jeff.liu@oracle.com>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

diff --git a/fs/xfs/xfs_trans_resv.c b/fs/xfs/xfs_trans_resv.c
index e9211ad..24110f3 100644
--- a/fs/xfs/xfs_trans_resv.c
+++ b/fs/xfs/xfs_trans_resv.c
@@ -547,7 +547,8 @@
  * Since the runtime attribute transaction space is dependent on the total
  * blocks needed for the 1st bmap, here we calculate out the space unit for
  * one block so that the caller could figure out the total space according
- * to the attibute extent length in blocks by: ext * XFS_ATTRSETRT_LOG_RES(mp).
+ * to the attibute extent length in blocks by:
+ *	ext * M_RES(mp)->tr_attrsetrt.tr_logres
  */
 STATIC uint
 xfs_calc_attrsetrt_reservation(
@@ -619,14 +620,14 @@
 
 /*
  * Allocating quota on disk if needed.
- *	the write transaction log space: XFS_WRITE_LOG_RES(mp)
+ *	the write transaction log space: M_RES(mp)->tr_write.tr_logres
  *	the unit of quota allocation: one system block size
  */
 STATIC uint
 xfs_calc_qm_dqalloc_reservation(
 	struct xfs_mount	*mp)
 {
-	return XFS_WRITE_LOG_RES(mp) +
+	return M_RES(mp)->tr_write.tr_logres +
 		xfs_calc_buf_res(1,
 			XFS_FSB_TO_B(mp, XFS_DQUOT_CLUSTER_SIZE_FSB) - 1);
 }