netfs: Add some write-side stats and clean up some stat names

Add some write-side stats to count buffered writes, buffered writethrough,
and writepages calls.

Whilst we're at it, clean up the naming on some of the existing stats
counters and organise the output into two sets.
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org

fs/netfs/buffered_read.c

@@ -282,7 +282,7 @@ int netfs_read_folio(struct file *file, struct folio *folio)
 	if (ret == -ENOMEM || ret == -EINTR || ret == -ERESTARTSYS)
 		goto discard;
 
-	netfs_stat(&netfs_n_rh_readpage);
+	netfs_stat(&netfs_n_rh_read_folio);
 	trace_netfs_read(rreq, rreq->start, rreq->len, netfs_read_trace_readpage);
 
 	/* Set up the output buffer */

fs/netfs/buffered_write.c

@@ -210,6 +210,9 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter,
 		if (!is_sync_kiocb(iocb))
 			wreq->iocb = iocb;
 		wreq->cleanup = netfs_cleanup_buffered_write;
+		netfs_stat(&netfs_n_wh_writethrough);
+	} else {
+		netfs_stat(&netfs_n_wh_buffered_write);
 	}
 
 	do {

fs/netfs/direct_write.c

@@ -145,7 +145,7 @@ ssize_t netfs_unbuffered_write_iter(struct kiocb *iocb, struct iov_iter *from)
 		return 0;
 
 	trace_netfs_write_iter(iocb, from);
-	netfs_stat(&netfs_n_rh_dio_write);
+	netfs_stat(&netfs_n_wh_dio_write);
 
 	ret = netfs_start_io_direct(inode);
 	if (ret < 0)

fs/netfs/internal.h

@@ -106,9 +106,8 @@ int netfs_end_writethrough(struct netfs_io_request *wreq, struct kiocb *iocb);
  */
 #ifdef CONFIG_NETFS_STATS
 extern atomic_t netfs_n_rh_dio_read;
-extern atomic_t netfs_n_rh_dio_write;
 extern atomic_t netfs_n_rh_readahead;
-extern atomic_t netfs_n_rh_readpage;
+extern atomic_t netfs_n_rh_read_folio;
 extern atomic_t netfs_n_rh_rreq;
 extern atomic_t netfs_n_rh_sreq;
 extern atomic_t netfs_n_rh_download;
@@ -125,6 +124,10 @@ extern atomic_t netfs_n_rh_write_begin;
 extern atomic_t netfs_n_rh_write_done;
 extern atomic_t netfs_n_rh_write_failed;
 extern atomic_t netfs_n_rh_write_zskip;
+extern atomic_t netfs_n_wh_buffered_write;
+extern atomic_t netfs_n_wh_writethrough;
+extern atomic_t netfs_n_wh_dio_write;
+extern atomic_t netfs_n_wh_writepages;
 extern atomic_t netfs_n_wh_wstream_conflict;
 extern atomic_t netfs_n_wh_upload;
 extern atomic_t netfs_n_wh_upload_done;

fs/netfs/stats.c

@@ -10,9 +10,8 @@
 #include "internal.h"
 
 atomic_t netfs_n_rh_dio_read;
-atomic_t netfs_n_rh_dio_write;
 atomic_t netfs_n_rh_readahead;
-atomic_t netfs_n_rh_readpage;
+atomic_t netfs_n_rh_read_folio;
 atomic_t netfs_n_rh_rreq;
 atomic_t netfs_n_rh_sreq;
 atomic_t netfs_n_rh_download;
@@ -29,6 +28,10 @@ atomic_t netfs_n_rh_write_begin;
 atomic_t netfs_n_rh_write_done;
 atomic_t netfs_n_rh_write_failed;
 atomic_t netfs_n_rh_write_zskip;
+atomic_t netfs_n_wh_buffered_write;
+atomic_t netfs_n_wh_writethrough;
+atomic_t netfs_n_wh_dio_write;
+atomic_t netfs_n_wh_writepages;
 atomic_t netfs_n_wh_wstream_conflict;
 atomic_t netfs_n_wh_upload;
 atomic_t netfs_n_wh_upload_done;
@@ -39,13 +42,17 @@ atomic_t netfs_n_wh_write_failed;
 
 int netfs_stats_show(struct seq_file *m, void *v)
 {
-	seq_printf(m, "Netfs  : DR=%u DW=%u RA=%u RP=%u WB=%u WBZ=%u\n",
+	seq_printf(m, "Netfs  : DR=%u RA=%u RF=%u WB=%u WBZ=%u\n",
 		   atomic_read(&netfs_n_rh_dio_read),
-		   atomic_read(&netfs_n_rh_dio_write),
 		   atomic_read(&netfs_n_rh_readahead),
-		   atomic_read(&netfs_n_rh_readpage),
+		   atomic_read(&netfs_n_rh_read_folio),
 		   atomic_read(&netfs_n_rh_write_begin),
 		   atomic_read(&netfs_n_rh_write_zskip));
+	seq_printf(m, "Netfs  : BW=%u WT=%u DW=%u WP=%u\n",
+		   atomic_read(&netfs_n_wh_buffered_write),
+		   atomic_read(&netfs_n_wh_writethrough),
+		   atomic_read(&netfs_n_wh_dio_write),
+		   atomic_read(&netfs_n_wh_writepages));
 	seq_printf(m, "Netfs  : ZR=%u sh=%u sk=%u\n",
 		   atomic_read(&netfs_n_rh_zero),
 		   atomic_read(&netfs_n_rh_short_read),

fs/netfs/write_issue.c

@@ -519,6 +519,7 @@ int new_netfs_writepages(struct address_space *mapping,
 	}
 
 	trace_netfs_write(wreq, netfs_write_trace_writeback);
+	netfs_stat(&netfs_n_wh_writepages);
 
 	do {
 		_debug("wbiter %lx %llx", folio->index, wreq->start + wreq->submitted);