[Cluster-devel] [GFS2 PATCH 09/11] gfs2: enhance log_blocks trace point to show log blocks free

[Bob Peterson]

This patch adds some code to enhance the log_blocks trace point. It
reports the number of free log blocks, and also adds new trace points
for revoke writes that were previously missing.

Signed-off-by: Bob Peterson <rpeterso at redhat.com>
---
 fs/gfs2/log.c        | 12 ++++++++++--
 fs/gfs2/trace_gfs2.h |  9 ++++++---
 2 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/fs/gfs2/log.c b/fs/gfs2/log.c
index 665e287bf4f1..489b6f5c605d 100644
--- a/fs/gfs2/log.c
+++ b/fs/gfs2/log.c
@@ -716,16 +716,24 @@ void gfs2_write_revokes(struct gfs2_sbd *sdp)
 		atomic_dec(&sdp->sd_log_blks_free);
 		/* If no blocks have been reserved, we need to also
 		 * reserve a block for the header */
-		if (!sdp->sd_log_blks_reserved)
+		if (!sdp->sd_log_blks_reserved) {
 			atomic_dec(&sdp->sd_log_blks_free);
+			trace_gfs2_log_blocks(sdp, -2, 7);
+		} else {
+			trace_gfs2_log_blocks(sdp, -1, 7);
+		}
 	}
 	gfs2_ail1_empty(sdp, max_revokes);
 	gfs2_log_unlock(sdp);
 
 	if (!sdp->sd_log_num_revoke) {
 		atomic_inc(&sdp->sd_log_blks_free);
-		if (!sdp->sd_log_blks_reserved)
+		if (!sdp->sd_log_blks_reserved) {
 			atomic_inc(&sdp->sd_log_blks_free);
+			trace_gfs2_log_blocks(sdp, 2, 7);
+		} else {
+			trace_gfs2_log_blocks(sdp, 1, 7);
+		}
 	}
 }
 
diff --git a/fs/gfs2/trace_gfs2.h b/fs/gfs2/trace_gfs2.h
index 1c4aa666e7e0..9d28be2a8b69 100644
--- a/fs/gfs2/trace_gfs2.h
+++ b/fs/gfs2/trace_gfs2.h
@@ -52,7 +52,8 @@
 	{ 3, "gfs2_log_flush" }, \
 	{ 4, "gfs2_log_flush2" }, \
 	{ 5, "log_refund" }, \
-	{ 6, "init_journal" })
+	{ 6, "init_journal" }, \
+				     { 7, "gfs2_write_revokes" })
 
 #define show_glock_flags(flags) __print_flags(flags, "",	\
 	{(1UL << GLF_LOCK),			"l" },		\
@@ -398,17 +399,19 @@ TRACE_EVENT(gfs2_log_blocks,
 		__field(        dev_t,  dev                     )
 		__field(	int,	blocks			)
 		__field(	int,	caller			)
+		__field(	int,	blks_free		)
 	),
 
 	TP_fast_assign(
 		__entry->dev		= sdp->sd_vfs->s_dev;
 		__entry->blocks		= blocks;
 		__entry->caller		= caller;
+		__entry->blks_free	= atomic_read(&sdp->sd_log_blks_free);
 	),
 
-	TP_printk("%u,%u log reserve %d %s", MAJOR(__entry->dev),
+	TP_printk("%u,%u log reserve %d %s %d", MAJOR(__entry->dev),
 		  MINOR(__entry->dev), __entry->blocks,
-		  lbcaller(__entry->caller))
+		  lbcaller(__entry->caller), __entry->blks_free)
 );
 
 /* Writing back the AIL */
-- 
2.26.2