ceph: add a new metric to keep track of remote object copies

This patch adds latency and size metrics for remote object copies
operations ("copyfrom").  For now, these metrics will be available on the
client only, they won't be sent to the MDS.
Signed-off-by: Luís Henriques <lhenriques@suse.de>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

fs/ceph/debugfs.c

@@ -167,7 +167,8 @@ static int metrics_file_show(struct seq_file *s, void *p)
 static const char * const metric_str[] = {
 	"read",
 	"write",
-	"metadata"
+	"metadata",
+	"copyfrom"
 };
 static int metrics_latency_show(struct seq_file *s, void *p)
 {

fs/ceph/file.c

@@ -2304,6 +2304,10 @@ static ssize_t ceph_do_objects_copy(struct ceph_inode_info *src_ci, u64 *src_off
 		else {
 			ceph_osdc_start_request(osdc, req, false);
 			ret = ceph_osdc_wait_request(osdc, req);
+			ceph_update_copyfrom_metrics(&fsc->mdsc->metric,
+						     req->r_start_latency,
+						     req->r_end_latency,
+						     object_size, ret);
 			ceph_osdc_put_request(req);
 		}
 		if (ret) {

fs/ceph/metric.h

@@ -129,6 +129,7 @@ enum metric_type {
 	METRIC_READ,
 	METRIC_WRITE,
 	METRIC_METADATA,
+	METRIC_COPYFROM,
 	METRIC_MAX
 };
 
@@ -214,4 +215,11 @@ static inline void ceph_update_metadata_metrics(struct ceph_client_metric *m,
 	ceph_update_metrics(&m->metric[METRIC_METADATA],
 			    r_start, r_end, 0, rc);
 }
+static inline void ceph_update_copyfrom_metrics(struct ceph_client_metric *m,
+						ktime_t r_start, ktime_t r_end,
+						unsigned int size, int rc)
+{
+	ceph_update_metrics(&m->metric[METRIC_COPYFROM],
+			    r_start, r_end, size, rc);
+}
 #endif /* _FS_CEPH_MDS_METRIC_H */