- put some common code in a function handle_remount();

- add better checks on non-existing directories to prevent error
  messages at run time;
- introduce a function log() to help debugging diskless booting
  when things don't work;
- modify the parsing of diskless_remount so you can add mount_nfs
  options after the pathname. You could use 'remount' to do something
  similar, but this way is more convenient because you don't have to
  hardwire the server name in the command.
- document the above.

I have been running the above in a diskless lab since february on RELENG_6.

MFC after: 1 week

1 files changed, 43 insertions, 38 deletions

diff --git a/etc/rc.initdiskless b/etc/rc.initdiskless
index 90ac718..744d767 100644
--- a/etc/rc.initdiskless
+++ b/etc/rc.initdiskless
@@ -70,12 +70,13 @@
 #		then /dev/ad0s3 will be be mounted on /conf/1.2.3.4/foo/
 #
 # /conf/T/M/diskless_remount
-#		The contents of the file points to an NFS filesystem. E.g. if
-#		/conf/base/etc/diskless_remount contains "foo.com:/etc",
-#		then foo.com:/etc will be be mounted on /conf/base/etc/
-#		If the file contains a pathname starting with "/", then
-#		the root path is prepended to it; this allows relocation of
-#		the root filesystem without changing configuration files.
+#		The contents of the file points to an NFS filesystem,
+#		possibly followed by mount_nfs options. If the server name
+#		is omitted, the script will prepend the root path used when
+#		booting. E.g. if you booted from foo.com:/path/to/root,
+#		an entry for /conf/base/etc/diskless_remount could be any of
+#			foo.com:/path/to/root/etc
+#			/etc -o ro
 #		Because mount_nfs understands ".." in paths, it is
 #		possible to mount from locations above the NFS root with
 #		paths such as "/../../etc".
@@ -132,6 +133,14 @@
 
 dlv=`/sbin/sysctl -n vfs.nfs.diskless_valid 2> /dev/null`
 
+# DEBUGGING
+# log something on stdout if verbose.
+o_verbose=0     # set to 1 or 2 if you want more debugging
+log() {
+    [ ${o_verbose} -gt 0 ] && echo "*** $* ***"
+    [ ${o_verbose} -gt 1 ] && read -p "=== Press enter to continue" foo
+}
+
 # chkerr:
 #
 # Routine to check for error
@@ -151,6 +160,23 @@ chkerr() {
     esac
 }
 
+# The list of filesystems to umount after the copy
+to_umount=""
+
+handle_remount() { # $1 = mount point
+    local nfspt mountopts b
+    b=$1
+    log handle_remount $1
+    [ -d $b -a -f $b/diskless_remount ] || return
+    read nfspt mountopts < $b/diskless_remount
+    log "nfspt ${nfspt} mountopts ${mountopts}"
+    # prepend the nfs root if not present
+    [ `expr "$nfspt" : '\(.\)'` = "/" ] && nfspt="${nfsroot}${nfspt}"
+    mount_nfs $mountopts $nfspt $b
+    chkerr $? "mount_nfs $nfspt $b"
+    to_umount="$b ${to_umount}"
+}
+
 # Create a generic memory disk
 #
 mount_md() {
@@ -160,16 +186,16 @@ mount_md() {
 # Create the memory filesystem if it has not already been created
 #
 create_md() {
-    if [ "x`eval echo \\$md_created_$1`" = "x" ]; then
+	[ "x`eval echo \\$md_created_$1`" = "x" ] || return # only once
 	if [ "x`eval echo \\$md_size_$1`" = "x" ]; then
 	    md_size=10240
 	else
 	    md_size=`eval echo \\$md_size_$1`
 	fi
+	log create_md $1 with size $md_size
 	mount_md $md_size /$1
 	/bin/chmod 755 /$1
 	eval md_created_$1=created
-    fi
 }
 
 # DEBUGGING
@@ -205,7 +231,7 @@ if [ ${dlv:=0} -ne 0 ] ; then
 	echo "Interface ${bootp_ifc} IP-Address ${bootp_ipa} Broadcast ${bootp_ipbca} ${class}"
 fi
 
-# Figure out our NFS root path
+log Figure out our NFS root path
 #
 set -- `mount -t nfs`
 while [ $# -ge 1 ] ; do
@@ -228,19 +254,8 @@ if [ -n "${bootp_ipa}" ]; then
 	templates="${templates} ${bootp_ipa} ip/${bootp_ipa}"
 fi
 
-# The list of filesystems to umount after the copy
-to_umount=""
-
 # If /conf/diskless_remount exists, remount all of /conf.
-if [ -d /conf -a -f /conf/diskless_remount ]; then
-    nfspt=`/bin/cat /conf/diskless_remount`
-    if [ `expr "$nfspt" : '\(.\)'` = "/" ]; then
-	nfspt="${nfsroot}${nfspt}"
-    fi
-    mount_nfs $nfspt /conf
-    chkerr $? "mount_nfs $nfspt /conf"
-    to_umount="/conf"
-fi
+handle_remount /conf
 
 # Resolve templates in /conf/base, /conf/default, /conf/${bootp_ipbca},
 # and /conf/${bootp_ipa}.  For each subdirectory found within these
@@ -262,18 +277,17 @@ fi
 #   it before attemping to the remount.  This allows the root to be
 #   relocated without needing to change the remount files.
 #
+log "templates are ${templates}"
 for i in ${templates} ; do
     for j in /conf/$i/* ; do
+	[ -d $j ] || continue
+
 	# memory filesystem size specification
-	#
 	subdir=${j##*/}
-	if [ -d $j -a -f $j/md_size ]; then
-	    eval md_size_$subdir=`cat $j/md_size`
-	fi
+	[ -f $j/md_size ] && eval md_size_$subdir=`cat $j/md_size`
 
-	# remount
-	#
-	if [ -d $j -a -f $j/remount ]; then
+	# remount. Beware, the command is in the file itself!
+	if [ -f $j/remount ]; then
 	    nfspt=`/bin/cat $j/remount`
 	    $nfspt $j
 	    chkerr $? "$nfspt $j"
@@ -281,16 +295,7 @@ for i in ${templates} ; do
 	fi
 
 	# NFS remount
-	#
-	if [ -d $j -a -f $j/diskless_remount ]; then
-	    nfspt=`/bin/cat $j/diskless_remount`
-	    if [ `expr "$nfspt" : '\(.\)'` = "/" ]; then
-		nfspt="${nfsroot}${nfspt}"
-	    fi
-	    mount_nfs $nfspt $j
-	    chkerr $? "mount_nfs $nfspt $j"
-	    to_umount="$j ${to_umount}"
-	fi
+	handle_remount $j
     done
 done