From: Stefan Sperling <stsp@stsp.name>
Subject: Re: vi struggling to save commit messages
To: Ted Bullock <tbullock@comlore.com>
Cc: "Todd C. Miller" <Todd.Miller@sudo.ws>, gameoftrees@openbsd.org
Date: Wed, 8 Mar 2023 22:19:35 +0100

On Wed, Mar 08, 2023 at 01:54:24PM -0700, Ted Bullock wrote:
> 
> On 2023-03-08 1:24 p.m., Todd C. Miller wrote:
> > On Wed, 08 Mar 2023 13:19:39 -0700, Ted Bullock wrote:
> > 
> >> I can see why it triggers, it's comparing identical timestamps, not
> >> relative. This is inconsistent with the error text too which explicitly
> >> says "file modified more recently than this copy".
> >>
> >> timespeccmp(&sb.st_mtim, &ep->mtim, !=)
> >>
> >> should be
> >>
> >> timespeccmp(&sb.st_mtim, &ep->mtim, <=)
> > 
> > Are you saying that the current mtime is _older_ than the original?
> > Is this just a matter of the nsec portion being truncated?
> > 
> >  - todd
> 
> Here is a sample of the actual numbers, it's not a truncation.
> 
> sb.st_mtim.tv_sec: 1678308226, sb.st_mtim.tv_nsec: 125222348
> ep->mtim.tv_sec: 1678308226, ep->mtim.tv_nsec: 55250221

I can reproduce this with Vim on an NFS share between two amd64 systems.

Running fsync() before starting the editor fixes it for me.

diff /home/stsp/src/got
commit - 4931293229292383086fb2ddd615c3df18de0bba
path + /home/stsp/src/got
blob - e95ba2936e96e58c1f16c13b3a81b482f35d02a4
file + got/got.c
--- got/got.c
+++ got/got.c
@@ -518,6 +518,10 @@ collect_import_msg(char **logmsg, char **logmsg_path, 
 		err = got_error_from_errno2("write", *logmsg_path);
 		goto done;
 	}
+	if (fsync(fd) == -1) {
+		err = got_error_from_errno2("fsync", *logmsg_path);
+		goto done;
+	}
 
 	err = edit_logmsg(logmsg, editor, *logmsg_path, initial_content,
 	    initial_content_len, 1);
@@ -7407,6 +7411,10 @@ get_tag_message(char **tagmsg, char **tagmsg_path, con
 		err = got_error_from_errno2("write", *tagmsg_path);
 		goto done;
 	}
+	if (fsync(fd) == -1) {
+		err = got_error_from_errno2("fsync", *tagmsg_path);
+		goto done;
+	}
 
 	err = get_editor(&editor);
 	if (err)
@@ -8911,7 +8919,10 @@ collect_commit_logmsg(struct got_pathlist_head *commit
 		dprintf(fd, "# detailed changes can be viewed in %s\n",
 		    diff_path);
 	}
-
+	if (fsync(fd) == -1) {
+		err = got_error_from_errno2("fsync", a->logmsg_path);
+		goto done;
+	}
 	err = edit_logmsg(logmsg, a->editor, a->logmsg_path, initial_content,
 	    initial_content_len, a->prepared_log ? 0 : 1);
 done:
@@ -11710,8 +11721,14 @@ histedit_edit_logmsg(struct got_histedit_list_entry *h
 	if (err)
 		goto done;
 
-	write(fd, logmsg, logmsg_len);
-	close(fd);
+	if (write(fd, logmsg, logmsg_len) == -1) {
+		err = got_error_from_errno2("write", logmsg_path);
+		goto done;
+	}
+	if (fsync(fd) == -1) {
+		err = got_error_from_errno2("fsync", logmsg_path);
+		goto done;
+	}
 
 	err = get_editor(&editor);
 	if (err)