xfs: refactor space log reservation for XFS_TRANS_ATTR_SET

Currently, we calculate the attribute set transaction
log space reservation at runtime in two parts:

1) XFS_ATTRSET_LOG_RES() which is calcuated out at mount time.

2) ((ext * (mp)->m_sb.sb_sectsize) + \
    (ext * XFS_FSB_TO_B((mp), XFS_BM_MAXLEVELS(mp, XFS_ATTR_FORK))) + \
    (128 * (ext + (ext * XFS_BM_MAXLEVELS(mp, XFS_ATTR_FORK))))))
which is calculated out at runtime since it depend on the given extent length in blocks.

This patch renamed XFS_ATTRSET_LOG_RES(mp) to XFS_ATTRSETM_LOG_RES(mp) to indicate
that it is figured out at mount time.  Introduce XFS_ATTRSETRT_LOG_RES(mp) which would
be used to calculate out the unit of the log space reservation for one block.

In this way, the total runtime space for the given extent length can be figured out by:
XFS_ATTRSETM_LOG_RES(mp) + XFS_ATTRSETRT_LOG_RES(mp) * ext
Signed-off-by: Jie Liu <jeff.liu@oracle.com>
CC: Dave Chinner <david@fromorbit.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

fs/xfs/xfs_attr.c

@@ -300,9 +300,12 @@ xfs_attr_set_int(
 	if (rsvd)
 		args.trans->t_flags |= XFS_TRANS_RESERVE;
 
-	if ((error = xfs_trans_reserve(args.trans, args.total,
-			XFS_ATTRSET_LOG_RES(mp, args.total), 0,
-			XFS_TRANS_PERM_LOG_RES, XFS_ATTRSET_LOG_COUNT))) {
+	error = xfs_trans_reserve(args.trans, args.total,
+				  XFS_ATTRSETM_LOG_RES(mp) +
+				  XFS_ATTRSETRT_LOG_RES(mp) * args.total,
+				  0, XFS_TRANS_PERM_LOG_RES,
+				  XFS_ATTRSET_LOG_COUNT);
+	if (error) {
 		xfs_trans_cancel(args.trans, 0);
 		return(error);
 	}

fs/xfs/xfs_mount.h

@@ -34,7 +34,8 @@ typedef struct xfs_trans_reservations {
 	uint	tr_addafork;	/* cvt inode to attributed trans */
 	uint	tr_writeid;	/* write setuid/setgid file */
 	uint	tr_attrinval;	/* attr fork buffer invalidation */
-	uint	tr_attrset;	/* set/create an attribute */
+	uint	tr_attrsetm;	/* set/create an attribute at mount time */
+	uint	tr_attrsetrt;	/* set/create an attribute at runtime */
 	uint	tr_attrrm;	/* remove an attribute */
 	uint	tr_clearagi;	/* clear bad agi unlinked ino bucket */
 	uint	tr_growrtalloc;	/* grow realtime allocations */

fs/xfs/xfs_trans.c

@@ -489,17 +489,18 @@ xfs_calc_attrinval_reservation(
 }
 
 /*
- * Setting an attribute.
+ * Setting an attribute at mount time.
  *	the inode getting the attribute
  *	the superblock for allocations
  *	the agfs extents are allocated from
  *	the attribute btree * max depth
  *	the inode allocation btree
  * Since attribute transaction space is dependent on the size of the attribute,
- * the calculation is done partially at mount time and partially at runtime.
+ * the calculation is done partially at mount time and partially at runtime(see
+ * below).
  */
 STATIC uint
-xfs_calc_attrset_reservation(
+xfs_calc_attrsetm_reservation(
 	struct xfs_mount	*mp)
 {
 	return XFS_DQUOT_LOGRES(mp) +
@@ -508,6 +509,24 @@ xfs_calc_attrset_reservation(
 		xfs_calc_buf_res(XFS_DA_NODE_MAXDEPTH, XFS_FSB_TO_B(mp, 1));
 }
 
+/*
+ * Setting an attribute at runtime, transaction space unit per block.
+ * 	the superblock for allocations: sector size
+ *	the inode bmap btree could join or split: max depth * block size
+ * 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).
+ */
+STATIC uint
+xfs_calc_attrsetrt_reservation(
+	struct xfs_mount	*mp)
+{
+	return xfs_calc_buf_res(1, mp->m_sb.sb_sectsize) +
+		xfs_calc_buf_res(XFS_BM_MAXLEVELS(mp, XFS_ATTR_FORK),
+				 XFS_FSB_TO_B(mp, 1));
+}
+
 /*
  * Removing an attribute.
  *    the inode: inode size
@@ -641,7 +660,8 @@ xfs_trans_init(
 	resp->tr_writeid = xfs_calc_writeid_reservation(mp);
 	resp->tr_addafork = xfs_calc_addafork_reservation(mp);
 	resp->tr_attrinval = xfs_calc_attrinval_reservation(mp);
-	resp->tr_attrset = xfs_calc_attrset_reservation(mp);
+	resp->tr_attrsetm = xfs_calc_attrsetm_reservation(mp);
+	resp->tr_attrsetrt = xfs_calc_attrsetrt_reservation(mp);
 	resp->tr_attrrm = xfs_calc_attrrm_reservation(mp);
 	resp->tr_clearagi = xfs_calc_clear_agi_bucket_reservation(mp);
 	resp->tr_growrtalloc = xfs_calc_growrtalloc_reservation(mp);

fs/xfs/xfs_trans.h

@@ -255,11 +255,8 @@ struct xfs_log_item_desc {
 #define	XFS_WRITEID_LOG_RES(mp)		((mp)->m_reservations.tr_swrite)
 #define	XFS_ADDAFORK_LOG_RES(mp)	((mp)->m_reservations.tr_addafork)
 #define	XFS_ATTRINVAL_LOG_RES(mp)	((mp)->m_reservations.tr_attrinval)
-#define	XFS_ATTRSET_LOG_RES(mp, ext)	\
-	((mp)->m_reservations.tr_attrset + \
-	 (ext * (mp)->m_sb.sb_sectsize) + \
-	 (ext * XFS_FSB_TO_B((mp), XFS_BM_MAXLEVELS(mp, XFS_ATTR_FORK))) + \
-	 (128 * (ext + (ext * XFS_BM_MAXLEVELS(mp, XFS_ATTR_FORK)))))
+#define	XFS_ATTRSETM_LOG_RES(mp)	((mp)->m_reservations.tr_attrsetm)
+#define XFS_ATTRSETRT_LOG_RES(mp)	((mp)->m_reservations.tr_attrsetrt)
 #define	XFS_ATTRRM_LOG_RES(mp)		((mp)->m_reservations.tr_attrrm)
 #define	XFS_CLEAR_AGI_BUCKET_LOG_RES(mp)  ((mp)->m_reservations.tr_clearagi)
 #define XFS_QM_SBCHANGE_LOG_RES(mp)	((mp)->m_reservations.tr_qm_sbchange)