[PATCH v6 12/24] netfs: Defer the emission of trace_netfs_folio()

[David Howells]

Change netfs_perform_write() to keep the netfs_folio trace value in a
variable and emit it later to make it easier to choose the value displayed.
This is a prerequisite for a subsequent patch.

Closes: https://sashiko.dev/#/patchset/20260414082004.3756080-1-dhowells%40redhat.com
Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
cc: Paulo Alcantara <pc@xxxxxxxxxxxxx>
cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
cc: netfs@xxxxxxxxxxxxxxx
cc: linux-fsdevel@xxxxxxxxxxxxxxx
---
 fs/netfs/buffered_write.c | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/fs/netfs/buffered_write.c b/fs/netfs/buffered_write.c
index b6ecd059dc4f..278aeb074e75 100644
--- a/fs/netfs/buffered_write.c
+++ b/fs/netfs/buffered_write.c
@@ -149,6 +149,7 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter,
 	}
 
 	do {
+		enum netfs_folio_trace trace;
 		struct netfs_folio *finfo;
 		struct netfs_group *group;
 		unsigned long long fpos;
@@ -222,7 +223,7 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter,
 			if (unlikely(copied == 0))
 				goto copy_failed;
 			netfs_set_group(folio, netfs_group);
-			trace_netfs_folio(folio, netfs_folio_is_uptodate);
+			trace = netfs_folio_is_uptodate;
 			goto copied;
 		}
 
@@ -238,7 +239,7 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter,
 			folio_zero_segment(folio, offset + copied, flen);
 			__netfs_set_group(folio, netfs_group);
 			folio_mark_uptodate(folio);
-			trace_netfs_folio(folio, netfs_modify_and_clear);
+			trace = netfs_modify_and_clear;
 			goto copied;
 		}
 
@@ -256,7 +257,7 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter,
 			}
 			__netfs_set_group(folio, netfs_group);
 			folio_mark_uptodate(folio);
-			trace_netfs_folio(folio, netfs_whole_folio_modify);
+			trace = netfs_whole_folio_modify;
 			goto copied;
 		}
 
@@ -283,7 +284,7 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter,
 			if (unlikely(copied == 0))
 				goto copy_failed;
 			netfs_set_group(folio, netfs_group);
-			trace_netfs_folio(folio, netfs_just_prefetch);
+			trace = netfs_just_prefetch;
 			goto copied;
 		}
 
@@ -297,7 +298,7 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter,
 			if (offset == 0 && copied == flen) {
 				__netfs_set_group(folio, netfs_group);
 				folio_mark_uptodate(folio);
-				trace_netfs_folio(folio, netfs_streaming_filled_page);
+				trace = netfs_streaming_filled_page;
 				goto copied;
 			}
 
@@ -312,7 +313,7 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter,
 			finfo->dirty_len = copied;
 			folio_attach_private(folio, (void *)((unsigned long)finfo |
 							     NETFS_FOLIO_INFO));
-			trace_netfs_folio(folio, netfs_streaming_write);
+			trace = netfs_streaming_write;
 			goto copied;
 		}
 
@@ -332,9 +333,9 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter,
 					folio_detach_private(folio);
 				folio_mark_uptodate(folio);
 				kfree(finfo);
-				trace_netfs_folio(folio, netfs_streaming_cont_filled_page);
+				trace = netfs_streaming_cont_filled_page;
 			} else {
-				trace_netfs_folio(folio, netfs_streaming_write_cont);
+				trace = netfs_streaming_write_cont;
 			}
 			goto copied;
 		}
@@ -350,6 +351,7 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter,
 		continue;
 
 	copied:
+		trace_netfs_folio(folio, trace);
 		flush_dcache_folio(folio);
 
 		/* Update the inode size if we moved the EOF marker */