The block-extroot package adds the capability for preinit to mount /overlay on
an external USB device. The attached patch extends
the capability to allow /overlay to be mounted on a sub-directory of the
external USB device.
I can see two uses for this:
1. I want to be able to use the USB device for other purposes as well, and
this keeps all the files in one place on the USB device
2. I can have multiple difference configurations on the USB device, and
select which one to boot through UCI configuration.
The option is configured through /etc/config/fstab, with an extra option,
rootfs_subdir, which is the sub-directory relative to the
root of the USB device. For example:
option rootfs_subdir /openwrt
would mount /overlay on the /openwrt sub-directory of the USB device. The patch
to /lib/functions/block.sh are purely to support this
additional option.
The patch also adds one extra level of searching for /etc/config/fstab, adding
a first choice option of looking on the USB device,
and if the file does not exist there, then tries /tmp/overlay/etc/config/fstab
(i.e. the internal flash jffs2 fs) and lastly the
/etc/config/fstab on the squashfs filesystem. This allows the configuration to
be managed entirely on the USB device, without touching
the internal flash, other than the initial setup of the internal
/etc/config/fstab to enable the external rootfs.
The patch has been done like this, rather than modifying
/lib/preinit/50-determine_usb_root, so that it works in conjunction with
the patch I submitted yesterday for kexec'ing a new kernel from the USB device
during the preinit process.
Signed-off-by: Quentin Armitage <[email protected]>
Index: package/block-extroot-subdir/files/52_usb_root_subdir
===================================================================
--- package/block-extroot-subdir/files/52_usb_root_subdir (revision 0)
+++ package/block-extroot-subdir/files/52_usb_root_subdir (revision 0)
@@ -0,0 +1,79 @@
+#!/bin/sh
+# Copyright (C) 2010 OpenWrt.org
+
+# This is free software, licensed under the GNU General Public License v2.
+#
+# /etc/config/fstab configures this script. It requires that the extroot mount
+# was successful, and uses /overlay that it mounted.
+#
+#Example config:
+#config mount
+# option enabled 1
+# option is_rootfs 1
+# option rootfs_subdir /usbroot
+#
+# This will remount /overlay/$rootfs_subdir on /overlay
+
+. /etc/functions.sh
+. /lib/functions/block.sh
+
+config_fstab_extroot() {
+ local cfg="$1"
+ local find_rootfs="$2"
+
+ mount_cb() {
+ shift
+ local enabled="$6"
+ shift
+ local is_rootfs="$9"
+ shift
+ local rootfs_subdir="$9"
+
+ if [ "$is_rootfs" = "1" ]; then
+ extroot_enabled="$enabled"
+ extroot_subdir="$rootfs_subdir"
+ fi
+ }
+ config_get_mount "$cfg"
+ reset_block_cb
+}
+
+check_extroot_enabled_or_subdir() {
+ local OLD_UCI_CONFIG_DIR="$UCI_CONFIG_DIR"
+
+ [ "$pi_extroot_mount_success" = "true" ] || return 0
+
+ # If the extroot (mounted on /overlay) has a config, use it, otherwise
+ # try jffs2 overlay
+ if [ -r "/overlay/etc/config/fstab" ]; then
+ UCI_CONFIG_DIR=/overlay/etc/config
+ elif [ "$jffs" = "/tmp/overlay" ] && [ -r
"/tmp/overlay/etc/config/fstab" ]; then
+ UCI_CONFIG_DIR=/tmp/overlay/etc/config
+ fi
+
+ extroot_enabled=0
+ extroot_subdir=
+
+ config_load fstab
+ config_foreach config_fstab_extroot mount 1
+
+ # check we want this enabled
+ if [ "$extroot_enabled" = "0" ]; then
+ # No
+ pi_extroot_mount_success=false
+ umount /overlay
+ pi_mount_skip_next="$pi_pre_extroot_skip_next"
+ pi_extroot_mount_success=0
+ else
+ [ -n "$extroot_subdir" ] && [ -d /overlay/"$extroot_subdir" ] &&
+ mkdir -p /tmp/overlay1 && \
+ mount --bind /overlay/"$extroot_subdir" /tmp/overlay1
&& \
+ umount /overlay && \
+ mount --move /tmp/overlay1 /overlay
+ fi
+
+ UCI_CONFIG_DIR="$OLD_UCI_CONFIG_DIR"
+ return 0
+}
+
+boot_hook_add preinit_mount_root check_extroot_enabled_or_subdir
Index: package/block-extroot-subdir/files/49_save_skip_next
===================================================================
--- package/block-extroot-subdir/files/49_save_skip_next (revision 0)
+++ package/block-extroot-subdir/files/49_save_skip_next (revision 0)
@@ -0,0 +1,12 @@
+#!/bin/sh
+# Copyright (C) 2010 OpenWrt.org
+
+# This is free software, licensed under the GNU General Public License v2.
+#
+# Saves pi_mount_skip_next
+
+save_mount_skip_next() {
+ pi_pre_extroot_skip_next="$pi_mount_skip_next"
+}
+
+boot_hook_add preinit_mount_root save_mount_skip_next
Index: package/block-extroot-subdir/Makefile
===================================================================
--- package/block-extroot-subdir/Makefile (revision 0)
+++ package/block-extroot-subdir/Makefile (revision 0)
@@ -0,0 +1,54 @@
+#
+# Copyright (C) 2010 OpenWrt.org
+#
+# This is free software, licensed under the GNU General Public License v2.
+#
+
+include $(TOPDIR)/rules.mk
+
+PKG_NAME:=block-extroot-subdir
+PKG_VERSION:=0.0.1
+PKG_RELEASE:=1
+
+PKG_BUILD_DIR := $(BUILD_DIR)/$(PKG_NAME)
+
+include $(INCLUDE_DIR)/package.mk
+
+define Package/block-extroot-subdir/Default
+ SECTION:=utils
+ CATEGORY:=Utilities
+ TITLE:=root filesystem on secondary storage subdir
+ SUBMENU:=disc
+endef
+
+define Package/block-extroot-subdir
+ $(call Package/block-extroot-subdir/Default)
+ MENU:=1
+ DEPENDS:=+block-extroot
+endef
+
+define Package/block-extroot-subdir/description
+ Based on the moduluarized preinit and firstboot, adds the option to have
+ the root filesystem on a subdirectory on storage other than the jffs or the
+ boot root device.
+ For a squashfs image this package must be installed into the image, not as
+ a package to add later.
+endef
+
+define Build/Prepare
+endef
+
+define Build/Configure
+endef
+
+define Build/Compile
+endef
+
+define Package/block-extroot-subdir/install
+ $(INSTALL_DIR) $(1)/lib/preinit
+ $(INSTALL_DATA) ./files/49_save_skip_next $(1)/lib/preinit/
+ $(INSTALL_DATA) ./files/52_usb_root_subdir $(1)/lib/preinit/
+endef
+
+$(eval $(call BuildPackage,block-extroot-subdir))
+
Index: package/block-mount/files/block.sh
===================================================================
--- package/block-mount/files/block.sh (revision 20584)
+++ package/block-mount/files/block.sh (working copy)
@@ -20,6 +20,8 @@
dmc_label="$9"
shift
dmc_is_rootfs="$9"
+ shift
+ dmc_rootfs_subdir="$9"
return 0
}
swap_cb() {
@@ -47,6 +49,8 @@
dmds_mount_label="$9"
shift
dmds_is_rootfs="$9"
+ shift
+ dmds_rootfs_subdir="$9"
return 0
}
swap_dev_section_cb() {
@@ -81,7 +85,8 @@
config_get gm_uuid "$1" uuid
config_get gm_label "$1" label
config_get_bool gm_is_rootfs "$1" is_rootfs 0
- mount_cb "$gm_cfg" "$gm_param" "$gm_target" "$gm_device" "$gm_fstype"
"$gm_options" "$gm_enabled" "$gm_enabled_fsck" "$gm_uuid" "$gm_label"
"$gm_is_rootfs"
+ config_get gm_rootfs_subdir "$1" rootfs_subdir
+ mount_cb "$gm_cfg" "$gm_param" "$gm_target" "$gm_device" "$gm_fstype"
"$gm_options" "$gm_enabled" "$gm_enabled_fsck" "$gm_uuid" "$gm_label"
"$gm_is_rootfs" "$gm_rootfs_subdir"
}
config_get_swap() {
@@ -193,6 +198,7 @@
local msbd_uuid=
local msbd_label=
local msbd_is_rootfs
+ local msbd_rootfs_subdir
local msbd_blkid_fstype_match=
mount_cb() {
local mc_cfg="$1"
@@ -205,6 +211,8 @@
local mc_label="$9"
shift
local mc_is_rootfs="$9"
+ shift
+ local mc_rootfs_subdir="$9"
local mc_found_device=""
mc_found_device="$(libmount_find_device_by_id "$mc_uuid"
"$mc_label" "$mc_device" "$mc_cfgdevice")"
@@ -219,12 +227,14 @@
msbd_uuid="$7"
msbd_label="$8"
msbd_is_rootfs="$9"
+ shift
+ msbd_rootfs_subdir="$9"
fi
return 0
}
config_foreach config_get_mount mount "$msbd_device"
[ -n "$msbd_mount_device" ] && config_create_mount_fstab_entry
"$msbd_mount_device" "$msbd_target" "$msbd_fstype" "$msbd_options"
"$msbd_enabled"
- mount_dev_section_cb "$msbd_mount_cfg" "$msbd_target"
"$msbd_mount_device" "$msbd_fstype" "$msbd_options" "$msbd_enabled"
"$msbd_enabled_fsck" "$msbd_uuid" "$msbd_label" "$msbd_is_rootfs"
+ mount_dev_section_cb "$msbd_mount_cfg" "$msbd_target"
"$msbd_mount_device" "$msbd_fstype" "$msbd_options" "$msbd_enabled"
"$msbd_enabled_fsck" "$msbd_uuid" "$msbd_label" "$msbd_is_rootfs"
"$msbd_rootfs_subdir"
reset_block_cb
}
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