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57dd4029c8
If the swap disk is larger than 1MiB, then use a 1MiB blocksize in `dd` On my machine using a large block size speeds up swap file creation: ``` / # time dd if=/dev/zero of=output bs=1024 count=1048576 1048576+0 records in 1048576+0 records out real 0m 4.61s user 0m 0.79s sys 0m 3.77s / # time dd if=/dev/zero of=output bs=1048576 count=1024 1024+0 records in 1024+0 records out real 0m 1.06s user 0m 0.00s sys 0m 1.04s ``` Signed-off-by: David Scott <dave.scott@docker.com>
147 lines
2.7 KiB
Bash
Executable File
147 lines
2.7 KiB
Bash
Executable File
#!/bin/sh
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set -e
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while [ $# -ge 1 ]; do
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key="$1"
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case $key in
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--debug)
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set -x
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;;
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--path)
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path="$2"
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shift # past argument
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;;
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--size)
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size="$2"
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shift # past argument
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;;
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--encrypt)
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ENCRYPT=true
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;;
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--condition)
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CONDITIONS="$CONDITIONS $2"
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shift
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;;
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*)
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echo "Unknown option passed to swapmaker: $key" # unknown option
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exit 1
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;;
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esac
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shift # past argument or value
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done
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function disksize_to_count {
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local blocksize=$1
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local origsize=$2
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local ret
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case $origsize in
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*G)
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ret=$(( ${origsize%%G} * 1024 * 1024 * 1024 ))
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;;
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*M)
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ret=$(( ${origsize%%M} * 1024 * 1024 ))
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;;
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*K)
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ret=$(( ${origsize%%K} * 1024 ))
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;;
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*)
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ret=$origsize
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;;
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esac
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ret=$(( $ret / $blocksize ))
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echo $ret
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}
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## make sure path is valid
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if [ -z "${path}" ]; then
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echo "swap: --file <path> must be defined"
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exit 1
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fi
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if [ "${path:0:5}" != "/var/" -o ${#path} -lt 6 ]; then
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echo "--file <path> option must be under /var"
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exit 1
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fi
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if [ -z "${size}" ]; then
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echo "swap: --size <size> must be defined"
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exit 1
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fi
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## check each of our conditions
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for cond in $CONDITIONS; do
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# split the condition parts
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IFS=: read condtype arg1 arg2 arg3 arg4 <<EOF
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$cond
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EOF
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case $condtype in
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part)
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partition=$arg1
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required=$arg2
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# check that the path exists as its own mount point
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set +e
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grep -qs $partition /proc/mounts
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is_mnt=$?
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set -e
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if [ $is_mnt -ne 0 ]; then
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[ "$required" == "true" ] && exit 1
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exit 0
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fi
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;;
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partsize)
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partition=$arg1
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minsize=$arg2
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required=$arg3
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# check that the partition on which it exists has sufficient size
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partsize=$(df -k $partition | tail -1 | awk '{print $2}')
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partsize=$(( $partsize * 1024 ))
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# convert minsize to bytes
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minsize=$(disksize_to_count 1 $minsize)
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if [ $partsize -lt $minsize ]; then
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[ "$required" == "true" ] && exit 1
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exit 0
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fi
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;;
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*)
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echo "Unknown condition: $cond"
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exit 1
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;;
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esac
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done
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## if a condition failed:
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### Required? exit 1
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### Else? exit 0
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if [ "$ENCRYPT" == "true" ]; then
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SWAPDEV=/dev/mapper/swapfile
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else
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SWAPDEV=$path
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fi
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if [ ! -f $path ] || ! [ $(stat -c "%s" $path) == $(disksize_to_count 1 $size) ]; then
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## Allocate the file
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## If possible use a large blocksize:
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bs=1048576 # 1 MiB
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if [ "$size" -lt "$bs" ]; then
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bs=1024 # fall back to 1KiB
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fi
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dd if=/dev/zero of=$path bs=$bs count=$(disksize_to_count $bs $size)
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chmod 0600 $path
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## was it encrypted? use cryptsetup and get the mapped device
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if [ "$ENCRYPT" == "true" ]; then
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# might need
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#loop=$(losetup -f)
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#losetup ${loop} ${path}
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cryptsetup open --type plain --key-file /dev/urandom --key-size=256 --cipher=aes-cbc-essiv:sha256 --offset=0 ${path} swapfile
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fi
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/sbin/mkswap $SWAPDEV
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fi
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/sbin/swapon $SWAPDEV
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