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New layout/recreate/default/150_wipe_disks.sh to wipe disks. The disks that will be completely wiped are those disks where in diskrestore.sh the create_disk_label function is called (the create_disk_label function calls "parted -s $disk mklabel $label") i.e. the disks that will be completely overwritten by diskrestore.sh. This implements #799 "Clean up disks before recreating partitions/volumes/filesystems/..." The intent is to be also used later as a precondition for the future new 'storage' stage/code as future replacement of the 'layout' stage/code cf. #2510
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usr/share/rear/layout/recreate/default/150_wipe_disks.sh
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| # The disks that will be completely wiped are those disks | ||
| # where in diskrestore.sh the create_disk_label function is called | ||
| # (the create_disk_label function calls "parted -s $disk mklabel $label") | ||
| # for example like | ||
| # create_disk_label /dev/sda gpt | ||
| # create_disk_label /dev/sdb msdos | ||
| # so in this example DISKS_TO_BE_WIPED="/dev/sda /dev/sdb" | ||
| # cf. layout/recreate/default/120_confirm_wipedisk_disks.sh | ||
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| # Log the currently existing block devices structure on the unchanged replacement hardware | ||
| # cf. how lsblk is called in layout/save/GNU/Linux/100_create_layout_file.sh | ||
| Log "Block devices structure on the unchanged replacement hardware before the disks $DISKS_TO_BE_WIPED will be wiped (lsblk):" | ||
| Log "$( lsblk -ipo NAME,KNAME,PKNAME,TRAN,TYPE,FSTYPE,SIZE,MOUNTPOINT || lsblk -io NAME,KNAME,FSTYPE,SIZE,MOUNTPOINT || lsblk -i || lsblk )" | ||
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| # Wipe RAID plus LVM plus LUKS metadata. | ||
| # To wipe RAID Superblocks it is sufficient to wipe 133 KiB at the beginning and at the end of the device. | ||
| # To wipe to wipe LVM metadata is should be sufficient to wipe 4 MiB at the beginning and at the end of the device. | ||
| # To wipe LUKS headers is should be sufficient to wipe 8 MiB at the beginning of the device. | ||
| # To wipe RAID superblocks plus LVM metadata plus LUKS headers it should be sufficient to | ||
| # wipe 8 MiB + 4 MiB + 1 MiB = 13 MiB at the beginning of the device and to | ||
| # wipe 4 MiB + 1 MiB = 5 MiB at the end of the device. | ||
| # To be future proof (perhaps LUKS may add a backup header at the end of the device) | ||
| # wiping 16 MiB at the beginning and at the end of the device should be sufficiently safe. | ||
| local disk_to_be_wiped children_to_be_wiped device_to_be_wiped device_to_be_wiped_size_bytes bytes_to_be_wiped dd_seek_byte | ||
| # 16 * 1024 * 1024 = 16777216 | ||
| local bytes_of_16_MiB=16777216 | ||
| for disk_to_be_wiped in $DISKS_TO_BE_WIPED ; do | ||
| # Get all child kernel devices of the disk_to_be_wiped in reverse ordering | ||
| # so that nested children/grandchildren are first, then children and the disk_to_be_wiped last | ||
| # which is the required ordering to wipe devices (from lowest nested up to the top level device). | ||
| # For example when "lsblk -ipo NAME,KNAME,PKNAME,TYPE,FSTYPE,SIZE,MOUNTPOINT /dev/sda" shows | ||
| # NAME KNAME PKNAME TYPE FSTYPE SIZE MOUNTPOINT | ||
| # /dev/sda /dev/sda disk 20G | ||
| # |-/dev/sda1 /dev/sda1 /dev/sda part 8M | ||
| # `-/dev/sda2 /dev/sda2 /dev/sda part crypto_LUKS 20G | ||
| # `-/dev/mapper/cr_ata-QEMU_HARDDISK_QM00001-part2 /dev/dm-0 /dev/sda2 crypt LVM2_member 20G | ||
| # |-/dev/mapper/system-swap /dev/dm-1 /dev/dm-0 lvm swap 2G [SWAP] | ||
| # |-/dev/mapper/system-root /dev/dm-2 /dev/dm-0 lvm btrfs 12.6G / | ||
| # `-/dev/mapper/system-home /dev/dm-3 /dev/dm-0 lvm xfs 5.4G /home | ||
| # then "lsblk -nipo KNAME /dev/sda | tac" shows | ||
| # /dev/dm-3 | ||
| # /dev/dm-2 | ||
| # /dev/dm-1 | ||
| # /dev/dm-0 | ||
| # /dev/sda2 | ||
| # /dev/sda1 | ||
| # /dev/sda | ||
| children_to_be_wiped="$( lsblk -nipo KNAME $disk_to_be_wiped | tac | tr -s '[:space:]' ' ' )" | ||
| # "lsblk -nipo KNAME $disk_to_be_wiped" does not work on SLES11-SP4 which is no longer supported since ReaR 2.6 | ||
| # but it works at least on SLES12-SP5 so we test that children_to_be_wiped is not empty to avoid issues on older systems: | ||
| if ! test "$children_to_be_wiped" ; then | ||
| LogPrintError "Skip wiping $disk_to_be_wiped (no output for 'lsblk -nipo KNAME $disk_to_be_wiped' or failed)" | ||
| continue | ||
| fi | ||
| LogPrint "Wiping child devices of $disk_to_be_wiped in reverse ordering: $children_to_be_wiped" | ||
| for device_to_be_wiped in $children_to_be_wiped ; do | ||
| if ! test -b $device_to_be_wiped ; then | ||
| LogPrintError "Skip wiping $device_to_be_wiped (no block device)" | ||
| continue | ||
| fi | ||
| # Get the size of the device in bytes which could be smaller than 16 MiB. | ||
| # For example a 'bios_grub' partition could be smaller (e.g only 8 MiB on SUSE systems) | ||
| # cf. the "lsblk -ipo NAME,KNAME,PKNAME,TYPE,FSTYPE,SIZE,MOUNTPOINT /dev/sda" output above. | ||
| device_to_be_wiped_size_bytes="$( lsblk -dbnipo SIZE $device_to_be_wiped )" | ||
| if ! test -b $device_to_be_wiped_size_byte ; then | ||
| LogPrintError "Skip wiping $device_to_be_wiped (no output for 'lsblk -dbnipo SIZE $device_to_be_wiped' or failed)" | ||
| continue | ||
| fi | ||
| # The actual work: | ||
| DebugPrint "Wiping device $device_to_be_wiped" | ||
| # By default wipe 16 MiB at the beginning and at the end of the device: | ||
| bytes_to_be_wiped=$bytes_of_16_MiB | ||
| # Wipe at most the size of the device in bytes: | ||
| test $device_to_be_wiped_size_bytes -lt $bytes_to_be_wiped && bytes_to_be_wiped=$device_to_be_wiped_size_bytes | ||
| # Wipe at the beginning of the device: | ||
| if ! dd bs=1M if=/dev/zero of=$device_to_be_wiped count=$bytes_to_be_wiped conv=notrunc,fsync iflag=count_bytes ; then | ||
| LogPrintError "Failed to wipe first $bytes_to_be_wiped bytes of $device_to_be_wiped ('dd if=/dev/zero of=$device_to_be_wiped count=$bytes_to_be_wiped iflag=count_bytes' failed)" | ||
| else | ||
| Log "Wiped first $bytes_to_be_wiped bytes of $device_to_be_wiped" | ||
| fi | ||
| # Wipe at the end of the device: | ||
| if ! test $device_to_be_wiped_size_bytes -gt $bytes_to_be_wiped ; then | ||
| Log "Skip wiping at the end of $device_to_be_wiped (dvice size $device_to_be_wiped_size_bytes is not gerater than the bytes that were wiped)" | ||
| continue | ||
| fi | ||
| # The byte whereto dd should seek to wipe to the end of the device from that point: | ||
| dd_seek_byte=$(( device_to_be_wiped_size_bytes - bytes_to_be_wiped )) | ||
| if ! test $dd_seek_byte -gt 0 ; then | ||
| Log "Skip wiping at the end of $device_to_be_wiped (dd seek byte would be $dd_seek_byte)" | ||
| continue | ||
| fi | ||
| if ! dd bs=1M if=/dev/zero of=$device_to_be_wiped count=$bytes_to_be_wiped seek=$dd_seek_byte conv=notrunc,fsync iflag=count_bytes oflag=seek_bytes ; then | ||
| LogPrintError "Failed to wipe last $bytes_to_be_wiped bytes of $device_to_be_wiped ('dd if=/dev/zero of=$device_to_be_wiped count=$bytes_to_be_wiped seek=$dd_seek_byte iflag=count_bytes oflag=seek_bytes' failed)" | ||
| else | ||
| Log "Wiped last $bytes_to_be_wiped bytes of $device_to_be_wiped" | ||
| fi | ||
| done | ||
| done | ||
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| # Log the still existing block devices structure after the disks in DISKS_TO_BE_WIPED were wiped: | ||
| Log "Remaining block devices structure after the disks $DISKS_TO_BE_WIPED were wiped (lsblk):" | ||
| Log "$( lsblk -ipo NAME,KNAME,PKNAME,TRAN,TYPE,FSTYPE,SIZE,MOUNTPOINT || lsblk -io NAME,KNAME,FSTYPE,SIZE,MOUNTPOINT || lsblk -i || lsblk )" |