[src/trunk]: src Document how to resize the WAPBL log size.

[wiz <wiz%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/28e1e7d625e6
branches:  trunk
changeset: 783066:28e1e7d625e6
user:      wiz <wiz%NetBSD.org@localhost>
date:      Mon Dec 03 12:28:06 2012 +0000

description:
Document how to resize the WAPBL log size.
Based on patch by Edgar Fu? <ef%math.uni-bonn.de@localhost>.

diffstat:

 sbin/tunefs/tunefs.8   |  11 ++++++++---
 share/man/man4/wapbl.4 |  12 ++++++++----
 2 files changed, 16 insertions(+), 7 deletions(-)

diffs (66 lines):

diff -r 96e4b5b72643 -r 28e1e7d625e6 sbin/tunefs/tunefs.8
--- a/sbin/tunefs/tunefs.8      Mon Dec 03 07:50:29 2012 +0000
+++ b/sbin/tunefs/tunefs.8      Mon Dec 03 12:28:06 2012 +0000
@@ -1,4 +1,4 @@
-.\"    $NetBSD: tunefs.8,v 1.41 2012/04/08 22:00:37 wiz Exp $
+.\"    $NetBSD: tunefs.8,v 1.42 2012/12/03 12:28:06 wiz Exp $
 .\"
 .\" Copyright (c) 1983, 1991, 1993
 .\"    The Regents of the University of California.  All rights reserved.
@@ -29,7 +29,7 @@
 .\"
 .\"     @(#)tunefs.8   8.3 (Berkeley) 5/3/95
 .\"
-.Dd December 15, 2010
+.Dd December 3, 2012
 .Dt TUNEFS 8
 .Os
 .Sh NAME
@@ -102,7 +102,12 @@
 .Xr wapbl 4 .
 Specifying a size of zero will cause the in-filesystem journaling log file
 to be removed the next time the filesystem is mounted.
-The size of an existing in-filesystem journaling log file can not be changed.
+The size of an existing in-filesystem journaling log file can not be changed
+directly.
+You need to first set the log file size to zero, then mount the
+filesystem without logging enabled (which will remove the log without
+creating a new one), unmount, set the size to the new value and finally
+re-mount with logging enabled.
 .It Fl m Ar minfree
 This value specifies the percentage of space held back
 from normal users; the minimum free space threshold.
diff -r 96e4b5b72643 -r 28e1e7d625e6 share/man/man4/wapbl.4
--- a/share/man/man4/wapbl.4    Mon Dec 03 07:50:29 2012 +0000
+++ b/share/man/man4/wapbl.4    Mon Dec 03 12:28:06 2012 +0000
@@ -1,6 +1,6 @@
-.\"     $NetBSD: wapbl.4,v 1.14 2012/07/26 04:30:26 dholland Exp $
+.\"     $NetBSD: wapbl.4,v 1.15 2012/12/03 12:28:07 wiz Exp $
 .\"
-.\" Copyright (c) 2008, 2009 The NetBSD Foundation, Inc.
+.\" Copyright (c) 2008, 2009, 2012 The NetBSD Foundation, Inc.
 .\" All rights reserved.
 .\"
 .\" Redistribution and use in source and binary forms, with or without
@@ -24,7 +24,7 @@
 .\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 .\" POSSIBILITY OF SUCH DAMAGE.
 .\"
-.Dd July 26, 2012
+.Dd December 3, 2012
 .Dt WAPBL 4
 .Os
 .Sh NAME
@@ -122,7 +122,11 @@
 .Ed
 .Pp
 will remove the log and then re-create it with the default size.
-This method can also be used to grow or shrink the size of the journal.
+This method can also be used to grow or shrink the size of the journal
+by first scheduling the log for removal, then mounting read-write, but
+with logging disabled (so no new log will be created), then unmounting
+again, setting the desired log size and finally re-mounting with logging
+enabled.
 .Pp
 With the journal,
 .Xr fsck 8