diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
index fc500c6..4f5e148 100644
--- a/fs/xfs/xfs_mount.h
+++ b/fs/xfs/xfs_mount.h
@@ -43,6 +43,7 @@
 	uint	tr_qm_sbchange;	/* change quota flags */
 	uint	tr_qm_setqlim;	/* adjust quota limits */
 	uint	tr_qm_dqalloc;	/* allocate quota on disk */
+	uint	tr_qm_quotaoff;	/* turn quota off */
 } xfs_trans_reservations_t;
 
 #ifndef __KERNEL__
diff --git a/fs/xfs/xfs_qm_syscalls.c b/fs/xfs/xfs_qm_syscalls.c
index 1476b6f..4605f89 100644
--- a/fs/xfs/xfs_qm_syscalls.c
+++ b/fs/xfs/xfs_qm_syscalls.c
@@ -672,14 +672,10 @@
 	uint			oldsbqflag=0;
 
 	tp = xfs_trans_alloc(mp, XFS_TRANS_QM_QUOTAOFF);
-	if ((error = xfs_trans_reserve(tp, 0,
-				      sizeof(xfs_qoff_logitem_t) * 2 +
-				      mp->m_sb.sb_sectsize + 128,
-				      0,
-				      0,
-				      XFS_DEFAULT_LOG_COUNT))) {
+	error = xfs_trans_reserve(tp, 0, XFS_QM_QUOTAOFF_LOG_RES(mp),
+				  0, 0, XFS_DEFAULT_LOG_COUNT);
+	if (error)
 		goto error0;
-	}
 
 	qoffi = xfs_trans_get_qoff_item(tp, NULL, flags & XFS_ALL_QUOTA_ACCT);
 	xfs_trans_log_quotaoff_item(tp, qoffi);
diff --git a/fs/xfs/xfs_trans.c b/fs/xfs/xfs_trans.c
index 6dd2c04..a557c82 100644
--- a/fs/xfs/xfs_trans.c
+++ b/fs/xfs/xfs_trans.c
@@ -582,6 +582,19 @@
 }
 
 /*
+ * Turning off quotas.
+ *    the xfs_qoff_logitem_t: sizeof(struct xfs_qoff_logitem) * 2
+ *    the superblock for the quota flags: sector size
+ */
+STATIC uint
+xfs_calc_qm_quotaoff_reservation(
+	struct xfs_mount	*mp)
+{
+	return sizeof(struct xfs_qoff_logitem) * 2 +
+		xfs_calc_buf_res(1, mp->m_sb.sb_sectsize);
+}
+
+/*
  * Initialize the precomputed transaction reservation values
  * in the mount structure.
  */
@@ -615,6 +628,7 @@
 	resp->tr_qm_sbchange = xfs_calc_qm_sbchange_reservation(mp);
 	resp->tr_qm_setqlim = xfs_calc_qm_setqlim_reservation(mp);
 	resp->tr_qm_dqalloc = xfs_calc_qm_dqalloc_reservation(mp);
+	resp->tr_qm_quotaoff = xfs_calc_qm_quotaoff_reservation(mp);
 }
 
 /*
diff --git a/fs/xfs/xfs_trans.h b/fs/xfs/xfs_trans.h
index 04575db..1e103da 100644
--- a/fs/xfs/xfs_trans.h
+++ b/fs/xfs/xfs_trans.h
@@ -265,6 +265,7 @@
 #define XFS_QM_SBCHANGE_LOG_RES(mp)	((mp)->m_reservations.tr_qm_sbchange)
 #define XFS_QM_SETQLIM_LOG_RES(mp)	((mp)->m_reservations.tr_qm_setqlim)
 #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)
 
 /*
  * Various log count values.