I considered a simpler approach without sfdisk, however /proc/partitions
may not update after writing the image directly to the disk with dd, so
an approach that actually read the partition table from the device was
used. Also, /proc/partitions just lists block count, and not partition
begin/end info.
As for the merit, this is quite useful on x86 systems. For example, I'm
booting using a 32gb usb drive and would prefer to keep the other
partitions I have defined intact after an upgrade.
On 1/16/2016 9:24 PM, Luiz Angelo Daros de Luca wrote:
Rob, I'll not judge the merit of keeping the previous position table,
but I guess dd might be enough for saving/restore partitions (I guess
only msdos is used). dd and /proc/partitions might replace sfdisk.
Em sáb, 16 de jan de 2016 23:22, Rob Mosher
<nyt-open...@countercultured.net
<mailto:nyt-open...@countercultured.net>> escreveu:
This patch will save the partition table before an upgrade.
If the installed image has not changed the partition structure
the saved table will be restored, ensuring any user created
partitions will be present after the upgrade.
An option is added to sysupgrade to disable this feature.
Signed-off-by: Rob Mosher <nyt-open...@countercultured.net
<mailto:nyt-open...@countercultured.net>>
---
package/base-files/files/lib/upgrade/common.sh | 1 +
package/base-files/files/sbin/sysupgrade | 3 ++
target/linux/x86/Makefile | 2 +
.../linux/x86/base-files/lib/upgrade/platform.sh | 45
++++++++++++++++++++++
4 files changed, 51 insertions(+)
diff --git a/package/base-files/files/lib/upgrade/common.sh
b/package/base-files/files/lib/upgrade/common.sh
index 761b4c1..aed7f8e 100644
--- a/package/base-files/files/lib/upgrade/common.sh
+++ b/package/base-files/files/lib/upgrade/common.sh
@@ -67,6 +67,7 @@ run_ramfs() { # <command> [...]
install_bin /usr/sbin/ubirsvol
install_bin /usr/sbin/ubirmvol
install_bin /usr/sbin/ubimkvol
+ install_bin /usr/sbin/sfdisk
for file in $RAMFS_COPY_BIN; do
install_bin ${file//:/ }
done
diff --git a/package/base-files/files/sbin/sysupgrade
b/package/base-files/files/sbin/sysupgrade
index 93f0749..2f441f8 100755
--- a/package/base-files/files/sbin/sysupgrade
+++ b/package/base-files/files/sbin/sysupgrade
@@ -10,6 +10,7 @@ export INTERACTIVE=0
export VERBOSE=1
export SAVE_CONFIG=1
export SAVE_OVERLAY=0
+export SAVE_PARTITIONS=1
export DELAY=
export CONF_IMAGE=
export CONF_BACKUP_LIST=0
@@ -29,6 +30,7 @@ while [ -n "$1" ]; do
-q) export VERBOSE="$(($VERBOSE - 1))";;
-n) export SAVE_CONFIG=0;;
-c) export SAVE_OVERLAY=1;;
+ -p) export SAVE_PARTITIONS=0;;
-b|--create-backup) export CONF_BACKUP="$2"
NEED_IMAGE=1; shift;;
-r|--restore-backup) export CONF_RESTORE="$2"
NEED_IMAGE=1; shift;;
-l|--list-backup) export CONF_BACKUP_LIST=1; break;;
@@ -62,6 +64,7 @@ upgrade-option:
-i interactive mode
-c attempt to preserve all changed files in /etc/
-n do not save configuration over reflash
+ -p do not attempt to restore the partition table
after flash.
-T | --test
Verify image and config .tar.gz but do not
actually flash.
-F | --force
diff --git a/target/linux/x86/Makefile b/target/linux/x86/Makefile
index e4bc0d9..e5b4378 100644
--- a/target/linux/x86/Makefile
+++ b/target/linux/x86/Makefile
@@ -13,6 +13,8 @@ FEATURES:=squashfs ext4 vdi vmdk pcmcia targz
SUBTARGETS=generic xen_domu ep80579 geode kvm_guest 64
MAINTAINER:=Felix Fietkau <n...@openwrt.org <mailto:n...@openwrt.org>>
+DEFAULT_PACKAGES += sfdisk
+
KERNEL_PATCHVER:=4.4
KERNELNAME:=bzImage
diff --git a/target/linux/x86/base-files/lib/upgrade/platform.sh
b/target/linux/x86/base-files/lib/upgrade/platform.sh
index 73ab5ef..7f5a2b1 100644
--- a/target/linux/x86/base-files/lib/upgrade/platform.sh
+++ b/target/linux/x86/base-files/lib/upgrade/platform.sh
@@ -55,12 +55,57 @@ platform_copy_config() {
fi
}
+save_bootparts() {
+ disk=${BOOTPART%[0-9]}
+ if [ -b $disk ]; then
+ echo "Backing up partition table..."
+ sfdisk -d $disk > /tmp/sfdisk.before
+ grep size= /tmp/sfdisk.before | grep -E -v
'size=\s+0,' > /tmp/sfdisk.before.nonempty
+ fi
+}
+
+restore_bootparts() {
+ disk=${BOOTPART%[0-9]}
+ if [ -b $disk ]; then
+ sfdisk -d $disk > /tmp/sfdisk.after
+ grep size= /tmp/sfdisk.after | grep -E -v
'size=\s+0,' > /tmp/sfdisk.after.nonempty
+ before=$(cat /tmp/sfdisk.before.nonempty)
+ after=$(cat /tmp/sfdisk.after.nonempty)
+
+ #ensure we have both partition tables
+ if [ -z "$before" -o -z "$after" ]; then
+ echo "Could not read partition table"
+ return 1
+ fi
+
+ #if nothing changed, we do not need to restore
+ if [ "$before" = "$after" ]; then
+ echo "Parition layout unchanged"
+ return 0
+ fi
+
+ diff=$(grep -F -x -v -f
/tmp/sfdisk.before.nonempty /tmp/sfdisk.after.nonempty)
+
+ #if partition layout changed, do not restore
+ if [ -n "$diff" ]; then
+ echo "Partition layout changed, not
restoring."
+ return 1
+ fi
+
+ echo "Restoring partition table..."
+ sfdisk $disk --force < /tmp/sfdisk.before >&/dev/null
+ fi
+}
+
platform_do_upgrade() {
platform_export_bootpart
if [ -b "${BOOTPART%[0-9]}" ]; then
sync
+ [ $SAVE_PARTITIONS = "1" ] && save_bootparts
get_image "$@" | dd of="${BOOTPART%[0-9]}" bs=4096
conv=fsync
sleep 1
+ [ $SAVE_PARTITIONS = "1" ] && restore_bootparts
fi
}
+
--
2.1.4
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--
Luiz Angelo Daros de Luca
luizl...@gmail.com <mailto:luizl...@gmail.com>
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