xfs: introduce XFS_SB_LOG_RES() for transactions that modify sb on disk

Introduce a new transaction space reservation XFS_SB_LOG_RES() for
those transactions that need to modify the superblock on disk.
Signed-off-by: NJie Liu <jeff.liu@oracle.com>
CC: Dave Chinner <david@fromorbit.com>
Reviewed-by: NMark Tinguely <tinguely@sgi.com>
Signed-off-by: NBen Myers <bpm@sgi.com>

fs/xfs/xfs_mount.h

@@ -45,6 +45,7 @@ typedef struct xfs_trans_reservations {
 	uint	tr_qm_dqalloc;	/* allocate quota on disk */
 	uint	tr_qm_quotaoff;	/* turn quota off */
 	uint	tr_qm_equotaoff;/* end of turn quota off */
+	uint	tr_sb;		/* modify superblock */
 } xfs_trans_reservations_t;
 
 #ifndef __KERNEL__

fs/xfs/xfs_trans.c

@@ -605,6 +605,17 @@ xfs_calc_qm_quotaoff_end_reservation(
 	return sizeof(struct xfs_qoff_logitem) * 2;
 }
 
+/*
+ * Syncing the incore super block changes to disk.
+ *     the super block to reflect the changes: sector size
+ */
+STATIC uint
+xfs_calc_sb_reservation(
+	struct xfs_mount	*mp)
+{
+	return xfs_calc_buf_res(1, mp->m_sb.sb_sectsize);
+}
+
 /*
  * Initialize the precomputed transaction reservation values
  * in the mount structure.
@@ -641,6 +652,7 @@ xfs_trans_init(
 	resp->tr_qm_dqalloc = xfs_calc_qm_dqalloc_reservation(mp);
 	resp->tr_qm_quotaoff = xfs_calc_qm_quotaoff_reservation(mp);
 	resp->tr_qm_equotaoff = xfs_calc_qm_quotaoff_end_reservation(mp);
+	resp->tr_sb = xfs_calc_sb_reservation(mp);
 }
 
 /*

fs/xfs/xfs_trans.h

@@ -267,6 +267,7 @@ struct xfs_log_item_desc {
 #define XFS_QM_DQALLOC_LOG_RES(mp)	((mp)->m_reservations.tr_qm_dqalloc)
 #define XFS_QM_QUOTAOFF_LOG_RES(mp)	((mp)->m_reservations.tr_qm_quotaoff)
 #define XFS_QM_QUOTAOFF_END_LOG_RES(mp)	((mp)->m_reservations.tr_qm_equotaoff)
+#define XFS_SB_LOG_RES(mp)		((mp)->m_reservations.tr_sb)
 
 /*
  * Various log count values.