xfs: trace log reservations at mount time

At each mount, emit the transaction reservation type information via
tracepoints.  This makes it easier to compare the log reservation info
calculated by the kernel and xfsprogs so that we can more easily diagnose
minimum log size failures on freshly formatted filesystems.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>

4 files changed, 52 insertions, 1 deletions

diff --git a/fs/xfs/libxfs/xfs_log_rlimit.c b/fs/xfs/libxfs/xfs_log_rlimit.c
index c10597973333..cc4cbe290939 100644
--- a/fs/xfs/libxfs/xfs_log_rlimit.c
+++ b/fs/xfs/libxfs/xfs_log_rlimit.c
@@ -55,7 +55,7 @@ xfs_log_calc_max_attrsetm_res(
  * the maximum one in terms of the pre-calculated values which were done
  * at mount time.
  */
-STATIC void
+void
 xfs_log_get_max_trans_res(
 	struct xfs_mount	*mp,
 	struct xfs_trans_res	*max_resp)
diff --git a/fs/xfs/libxfs/xfs_shared.h b/fs/xfs/libxfs/xfs_shared.h
index 67ccb1ab4d7e..d0b84da0cb1e 100644
--- a/fs/xfs/libxfs/xfs_shared.h
+++ b/fs/xfs/libxfs/xfs_shared.h
@@ -76,6 +76,9 @@ struct xfs_log_item_desc {
 int	xfs_log_calc_unit_res(struct xfs_mount *mp, int unit_bytes);
 int	xfs_log_calc_minimum_size(struct xfs_mount *);
 
+struct xfs_trans_res;
+void	xfs_log_get_max_trans_res(struct xfs_mount *mp,
+				  struct xfs_trans_res *max_resp);
 
 /*
  * Values for t_flags.
diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
index 9235b2c29695..b6251f8d66a0 100644
--- a/fs/xfs/xfs_trace.h
+++ b/fs/xfs/xfs_trace.h
@@ -3313,6 +3313,32 @@ DEFINE_GETFSMAP_EVENT(xfs_getfsmap_low_key);
 DEFINE_GETFSMAP_EVENT(xfs_getfsmap_high_key);
 DEFINE_GETFSMAP_EVENT(xfs_getfsmap_mapping);
 
+TRACE_EVENT(xfs_trans_resv_calc,
+	TP_PROTO(struct xfs_mount *mp, unsigned int type,
+		 struct xfs_trans_res *res),
+	TP_ARGS(mp, type, res),
+	TP_STRUCT__entry(
+		__field(dev_t, dev)
+		__field(int, type)
+		__field(uint, logres)
+		__field(int, logcount)
+		__field(int, logflags)
+	),
+	TP_fast_assign(
+		__entry->dev = mp->m_super->s_dev;
+		__entry->type = type;
+		__entry->logres = res->tr_logres;
+		__entry->logcount = res->tr_logcount;
+		__entry->logflags = res->tr_logflags;
+	),
+	TP_printk("dev %d:%d type %d logres %u logcount %d flags 0x%x",
+		  MAJOR(__entry->dev), MINOR(__entry->dev),
+		  __entry->type,
+		  __entry->logres,
+		  __entry->logcount,
+		  __entry->logflags)
+);
+
 #endif /* _TRACE_XFS_H */
 
 #undef TRACE_INCLUDE_PATH
diff --git a/fs/xfs/xfs_trans.c b/fs/xfs/xfs_trans.c
index a87f657f59c9..86f92df32c42 100644
--- a/fs/xfs/xfs_trans.c
+++ b/fs/xfs/xfs_trans.c
@@ -35,6 +35,27 @@
 kmem_zone_t	*xfs_trans_zone;
 kmem_zone_t	*xfs_log_item_desc_zone;
 
+#if defined(CONFIG_TRACEPOINTS)
+static void
+xfs_trans_trace_reservations(
+	struct xfs_mount	*mp)
+{
+	struct xfs_trans_res	resv;
+	struct xfs_trans_res	*res;
+	struct xfs_trans_res	*end_res;
+	int			i;
+
+	res = (struct xfs_trans_res *)M_RES(mp);
+	end_res = (struct xfs_trans_res *)(M_RES(mp) + 1);
+	for (i = 0; res < end_res; i++, res++)
+		trace_xfs_trans_resv_calc(mp, i, res);
+	xfs_log_get_max_trans_res(mp, &resv);
+	trace_xfs_trans_resv_calc(mp, -1, &resv);
+}
+#else
+# define xfs_trans_trace_reservations(mp)
+#endif
+
 /*
  * Initialize the precomputed transaction reservation values
  * in the mount structure.
@@ -44,6 +65,7 @@ xfs_trans_init(
 	struct xfs_mount	*mp)
 {
 	xfs_trans_resv_calc(mp, M_RES(mp));
+	xfs_trans_trace_reservations(mp);
 }
 
 /*