[PATCH] zonefs: add tracepoints for file operations

[Johannes Thumshirn <johannes.thumshirn@wdc.com>]

Add tracepoints for file I/O operations to aid in debugging of I/O errors
with zonefs.

The added tracepoints are in:
- zonefs_zone_mgmt() for tracing zone management operations
- zonefs_iomap_begin() for tracing regular file I/O
- zonefs_file_dio_append() for tracing zone-append operations

Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
---
 fs/zonefs/Makefile |   2 +
 fs/zonefs/super.c  |   7 +++
 fs/zonefs/trace.h  | 103 +++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 112 insertions(+)
 create mode 100644 fs/zonefs/trace.h

diff --git a/fs/zonefs/Makefile b/fs/zonefs/Makefile
index 75a380aa1ae1..33c1a4f1132e 100644
--- a/fs/zonefs/Makefile
+++ b/fs/zonefs/Makefile
@@ -1,4 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0
+ccflags-y				+= -I$(src)
+
 obj-$(CONFIG_ZONEFS_FS) += zonefs.o
 
 zonefs-y	:= super.o
diff --git a/fs/zonefs/super.c b/fs/zonefs/super.c
index bec47f2d074b..96f0cb0c29aa 100644
--- a/fs/zonefs/super.c
+++ b/fs/zonefs/super.c
@@ -24,6 +24,9 @@
 
 #include "zonefs.h"
 
+#define CREATE_TRACE_POINTS
+#include "trace.h"
+
 static inline int zonefs_zone_mgmt(struct inode *inode,
 				   enum req_opf op)
 {
@@ -32,6 +35,7 @@ static inline int zonefs_zone_mgmt(struct inode *inode,
 
 	lockdep_assert_held(&zi->i_truncate_mutex);
 
+	trace_zonefs_zone_mgmt(inode, op);
 	ret = blkdev_zone_mgmt(inode->i_sb->s_bdev, op, zi->i_zsector,
 			       zi->i_zone_size >> SECTOR_SHIFT, GFP_NOFS);
 	if (ret) {
@@ -100,6 +104,8 @@ static int zonefs_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
 	iomap->bdev = inode->i_sb->s_bdev;
 	iomap->addr = (zi->i_zsector << SECTOR_SHIFT) + iomap->offset;
 
+	trace_zonefs_iomap_begin(inode, iomap);
+
 	return 0;
 }
 
@@ -703,6 +709,7 @@ static ssize_t zonefs_file_dio_append(struct kiocb *iocb, struct iov_iter *from)
 	ret = submit_bio_wait(bio);
 
 	zonefs_file_write_dio_end_io(iocb, size, ret, 0);
+	trace_zonefs_file_dio_append(inode, size, ret);
 
 out_release:
 	bio_release_pages(bio, false);
diff --git a/fs/zonefs/trace.h b/fs/zonefs/trace.h
new file mode 100644
index 000000000000..d86f66c28e50
--- /dev/null
+++ b/fs/zonefs/trace.h
@@ -0,0 +1,103 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * zonefs filesystem driver tracepoints.
+ *
+ * Copyright (C) 2020 Western Digital Corporation or its affiliates.
+ */
+
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM zonefs
+
+#if !defined(_TRACE_ZONEFS_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_ZONEFS_H
+
+#include <linux/tracepoint.h>
+#include <linux/trace_seq.h>
+#include <linux/blkdev.h>
+
+#include "zonefs.h"
+
+#define show_dev(dev) MAJOR(dev), MINOR(dev)
+
+TRACE_EVENT(zonefs_zone_mgmt,
+	    TP_PROTO(struct inode *inode, enum req_opf op),
+	    TP_ARGS(inode, op),
+	    TP_STRUCT__entry(
+			     __field(dev_t, dev)
+			     __field(ino_t, ino)
+			     __field(int, op)
+			     __field(sector_t, sector)
+			     __field(sector_t, nr_sectors)
+	    ),
+	    TP_fast_assign(
+			   __entry->dev = inode->i_sb->s_dev;
+			   __entry->ino = inode->i_ino;
+			   __entry->op = op;
+			   __entry->sector = ZONEFS_I(inode)->i_zsector;
+			   __entry->nr_sectors =
+				   ZONEFS_I(inode)->i_zone_size >> SECTOR_SHIFT;
+	    ),
+	    TP_printk("bdev=(%d,%d), ino=%lu op=%s, sector=%llu, nr_sectors=%llu",
+		      show_dev(__entry->dev), __entry->ino,
+		      blk_op_str(__entry->op), __entry->sector,
+		      __entry->nr_sectors
+	    )
+);
+
+TRACE_EVENT(zonefs_file_dio_append,
+	    TP_PROTO(struct inode *inode, ssize_t size, ssize_t ret),
+	    TP_ARGS(inode, size, ret),
+	    TP_STRUCT__entry(
+			     __field(dev_t, dev)
+			     __field(ino_t, ino)
+			     __field(sector_t, sector)
+			     __field(ssize_t, size)
+			     __field(loff_t, wpoffset)
+			     __field(ssize_t, ret)
+	    ),
+	    TP_fast_assign(
+			   __entry->dev = inode->i_sb->s_dev;
+			   __entry->ino = inode->i_ino;
+			   __entry->sector = ZONEFS_I(inode)->i_zsector;
+			   __entry->size = size;
+			   __entry->wpoffset = ZONEFS_I(inode)->i_wpoffset;
+			   __entry->ret = ret;
+	    ),
+	    TP_printk("bdev=(%d, %d), ino=%lu, sector=%llu, size=%zu, wpoffset=%llu, ret=%zu",
+		      show_dev(__entry->dev), __entry->ino, __entry->sector,
+		      __entry->size, __entry->wpoffset, __entry->ret
+	    )
+);
+
+TRACE_EVENT(zonefs_iomap_begin,
+	    TP_PROTO(struct inode *inode, struct iomap *iomap),
+	    TP_ARGS(inode, iomap),
+	    TP_STRUCT__entry(
+			     __field(dev_t, dev)
+			     __field(ino_t, ino)
+			     __field(u64, addr)
+			     __field(loff_t, offset)
+			     __field(u64, length)
+	    ),
+	    TP_fast_assign(
+			   __entry->dev = inode->i_sb->s_dev;
+			   __entry->ino = inode->i_ino;
+			   __entry->addr = iomap->addr;
+			   __entry->offset = iomap->offset;
+			   __entry->length = iomap->length;
+	    ),
+	    TP_printk("bdev=(%d,%d), ino=%lu, addr=%llu, offset=%llu, length=%llu",
+		      show_dev(__entry->dev), __entry->ino, __entry->addr,
+		      __entry->offset, __entry->length
+	    )
+);
+
+#endif /* _TRACE_ZONEFS_H */
+
+#undef TRACE_INCLUDE_PATH
+#define TRACE_INCLUDE_PATH .
+#undef TRACE_INCLUDE_FILE
+#define TRACE_INCLUDE_FILE trace
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
-- 
2.26.2