xfs: remove lsn relevant fields from xfs_trans structure and its users

The t_lsn is not used anymore and the t_commit_lsn is used as a tmp
storage for the checkpoint sequence number only in the current code.

And the start/commit lsn are tracked as a transaction group tag in
the xfs_cil_ctx instead of a single transaction, so remove them from
the xfs_trans structure and their users to match with the design.

Signed-off-by: Shan Hai <shan.hai@oracle.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

fs/xfs/xfs_log_cil.c

@@ -993,6 +993,7 @@ xfs_log_commit_cil(
 {
 	struct xlog		*log = mp->m_log;
 	struct xfs_cil		*cil = log->l_cilp;
+	xfs_lsn_t		xc_commit_lsn;
 
 	/*
 	 * Do all necessary memory allocation before we lock the CIL.
@@ -1006,9 +1007,9 @@ xfs_log_commit_cil(
 
 	xlog_cil_insert_items(log, tp);
 
-	tp->t_commit_lsn = cil->xc_ctx->sequence;
+	xc_commit_lsn = cil->xc_ctx->sequence;
 	if (commit_lsn)
-		*commit_lsn = tp->t_commit_lsn;
+		*commit_lsn = xc_commit_lsn;
 
 	xfs_log_done(mp, tp->t_ticket, NULL, regrant);
 	xfs_trans_unreserve_and_mod_sb(tp);
@@ -1024,7 +1025,7 @@ xfs_log_commit_cil(
 	 * the log items. This affects (at least) processing of stale buffers,
 	 * inodes and EFIs.
 	 */
-	xfs_trans_free_items(tp, tp->t_commit_lsn, false);
+	xfs_trans_free_items(tp, xc_commit_lsn, false);
 
 	xlog_cil_push_background(log);
 

fs/xfs/xfs_trace.h

@@ -1491,25 +1491,6 @@ TRACE_EVENT(xfs_extent_busy_trim,
 		  __entry->tlen)
 );
 
-TRACE_EVENT(xfs_trans_commit_lsn,
-	TP_PROTO(struct xfs_trans *trans),
-	TP_ARGS(trans),
-	TP_STRUCT__entry(
-		__field(dev_t, dev)
-		__field(struct xfs_trans *, tp)
-		__field(xfs_lsn_t, lsn)
-	),
-	TP_fast_assign(
-		__entry->dev = trans->t_mountp->m_super->s_dev;
-		__entry->tp = trans;
-		__entry->lsn = trans->t_commit_lsn;
-	),
-	TP_printk("dev %d:%d trans 0x%p commit_lsn 0x%llx",
-		  MAJOR(__entry->dev), MINOR(__entry->dev),
-		  __entry->tp,
-		  __entry->lsn)
-);
-
 TRACE_EVENT(xfs_agf,
 	TP_PROTO(struct xfs_mount *mp, struct xfs_agf *agf, int flags,
 		 unsigned long caller_ip),

fs/xfs/xfs_trans.h

@@ -105,10 +105,6 @@ typedef struct xfs_trans {
 	unsigned int		t_rtx_res;	/* # of rt extents resvd */
 	unsigned int		t_rtx_res_used;	/* # of resvd rt extents used */
 	struct xlog_ticket	*t_ticket;	/* log mgr ticket */
-	xfs_lsn_t		t_lsn;		/* log seq num of start of
-						 * transaction. */
-	xfs_lsn_t		t_commit_lsn;	/* log seq num of end of
-						 * transaction. */
 	struct xfs_mount	*t_mountp;	/* ptr to fs mount struct */
 	struct xfs_dquot_acct   *t_dqinfo;	/* acctg info for dquots */
 	unsigned int		t_flags;	/* misc flags */