[PATCH] btrfs: add compression trace points

[Anand Jain <anand.jain@oracle.com>]

This patch adds compression and decompression trace points for the
purpose of debugging.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
---
Note:
 I have used same trace function for both compress and decompress
 as I wanted to maintain compress and decompress debug data aligned.

 fs/btrfs/compression.c       | 10 ++++++++++
 include/trace/events/btrfs.h | 36 ++++++++++++++++++++++++++++++++++++
 2 files changed, 46 insertions(+)

diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index ee934e612f15..9b0562cd1b7f 100644
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -938,6 +938,10 @@ int btrfs_compress_pages(int type, struct address_space *mapping,
 						      start, pages,
 						      out_pages,
 						      total_in, total_out);
+
+	trace_btrfs_encoder(1, 0, mapping->host, type, *total_in,
+						*total_out, start, ret);
+
 	free_workspace(type, workspace);
 	return ret;
 }
@@ -968,6 +972,9 @@ static int btrfs_decompress_bio(struct compressed_bio *cb)
 			cb->compressed_pages, cb->start, cb->orig_bio,
 			cb->compressed_len);
 
+	trace_btrfs_encoder(0, 1, cb->inode, type,
+				cb->compressed_len, cb->len, cb->start, ret);
+
 	free_workspace(type, workspace);
 	return ret;
 }
@@ -989,6 +996,9 @@ int btrfs_decompress(int type, unsigned char *data_in, struct page *dest_page,
 						  dest_page, start_byte,
 						  srclen, destlen);
 
+	trace_btrfs_encoder(0, 0, dest_page->mapping->host,
+				type, srclen, destlen, start_byte, ret);
+
 	free_workspace(type, workspace);
 	return ret;
 }
diff --git a/include/trace/events/btrfs.h b/include/trace/events/btrfs.h
index e37973526153..1ebffcd005a1 100644
--- a/include/trace/events/btrfs.h
+++ b/include/trace/events/btrfs.h
@@ -1658,6 +1658,42 @@ TRACE_EVENT(qgroup_meta_reserve,
 		show_root_type(__entry->refroot), __entry->diff)
 );
 
+TRACE_EVENT(btrfs_encoder,
+
+	TP_PROTO(int encode, int bio, struct inode *inode, int type,
+			unsigned long bfr, unsigned long aft,
+			unsigned long start, int ret),
+
+	TP_ARGS(encode, bio, inode, type, bfr, aft, start, ret),
+
+	TP_STRUCT__entry_btrfs(
+		__field(	int,		encode)
+		__field(	int,		bio)
+		__field(	unsigned long,	i_ino)
+		__field(	int,		type)
+		__field(	unsigned long,	bfr)
+		__field(	unsigned long,	aft)
+		__field(	unsigned long,	start)
+		__field(	int,		ret)
+	),
+
+	TP_fast_assign_btrfs(btrfs_sb(inode->i_sb),
+		__entry->encode		= encode;
+		__entry->bio		= bio;
+		__entry->i_ino		= inode->i_ino;
+		__entry->type		= type;
+		__entry->bfr		= bfr;
+		__entry->aft		= aft;
+		__entry->start		= start;
+		__entry->ret		= ret;
+	),
+
+	TP_printk_btrfs("%s %s ino:%lu tfm:%d bfr:%lu aft:%lu start:%lu ret:%d",
+		__entry->encode ? "encode":"decode",
+		__entry->bio ? "bio":"pge", __entry->i_ino, __entry->type,
+		__entry->bfr, __entry->aft, __entry->start, __entry->ret)
+
+);
 #endif /* _TRACE_BTRFS_H */
 
 /* This part must be outside protection */
-- 
2.10.0