Module Name: src
Committed By: gdt
Date: Sat Oct 21 23:38:26 UTC 2023
Modified Files:
src/usr.sbin/vnconfig: vnconfig.8
Log Message:
vnconfig: Improve recent caching edit to man page
Explain that typical usage patterns don't run into consistency issues.
Xref the -i flag.
Leave ambiguous the nature of cache inconsistency, because I don't
undersstand it and it's best not to make it a defined interface
anyway. I am unclear on whether a buffer cache read before a vnd
session might persist after a vnd is configured/used/unconfigured, and
whether a buffer cache write might be delayed until after a vnd
configure/write.
To generate a diff of this commit:
cvs rdiff -u -r1.48 -r1.49 src/usr.sbin/vnconfig/vnconfig.8
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/usr.sbin/vnconfig/vnconfig.8
diff -u src/usr.sbin/vnconfig/vnconfig.8:1.48 src/usr.sbin/vnconfig/vnconfig.8:1.49
--- src/usr.sbin/vnconfig/vnconfig.8:1.48 Fri Oct 20 13:04:21 2023
+++ src/usr.sbin/vnconfig/vnconfig.8 Sat Oct 21 23:38:26 2023
@@ -1,4 +1,4 @@
-.\" $NetBSD: vnconfig.8,v 1.48 2023/10/20 13:04:21 wiz Exp $
+.\" $NetBSD: vnconfig.8,v 1.49 2023/10/21 23:38:26 gdt Exp $
.\"
.\" Copyright (c) 1997 The NetBSD Foundation, Inc.
.\" All rights reserved.
@@ -100,12 +100,21 @@ The
is a special file of raw partition or name of vnode disk like
.Pa vnd0 .
.Pp
-By default, accesses to the file bypass normal mechanisms.
-This behavior results in not updating the modification timestamp
-of the file.
-Also, file contents read through the filesystem may not be the
-correct values of ciphertext, which can lead to corrupted backups of
-the backing file.
+By default, accesses to the file bypass normal mechanisms and thus
+do not read from or fill the filesystem cache.
+Because the typical approach is to access the file only via
+.Xr vnd 4 ,
+or at least to have regular accesses and
+.Xr vnd 4
+accesses separated in time, this is generally not problematic.
+This bypassing behavior results in not updating the modification
+timestamp of the file.
+Also, file contents read through the filesystem (and thus the
+filesystem's caching layer) may not be the correct values of
+ciphertext, so caution is in order for backups.
+The
+.Fl i
+option may be useful if it is necessary to avoid inconsistent caching.
.Pp
Options indicate an action to be performed:
.Bl -tag -width indent
