blob: 229b4783a11b62efddcf99461546785899e14813 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
|
#!/bin/sh
die() { printf "%s: Error: %s\n" "$0" "$*" >&2; exit 1; }
[ "$(id -u)" = 0 ] || die 'you are not root'
shrink()
{
shrinkmegs=100
while true; do
while ! btrfs filesystem resize -${shrinkmegs}M "$mountpoint"/; do
shrinkmegs=$((shrinkmegs - 10 ))
if [ $shrinkmegs -lt 10 ]; then
return
fi
done
done
}
btrfs_truncate()
{
local img="$1" bytes
# 548044800/1176715264 bytes used
bytes=$(file "$img" | sed -ne 's?.*/\([0-9]*\) bytes used.*?\1?p')
if [ "$bytes" ]; then
truncate -s "$bytes" "$img"
fi
}
main()
{
if [ -d "$1" ]; then
mountpoint -q "$1" || die "not a mountpoint: $1"
shrink "$1"
elif [ -f "$1" ]; then
mkdir "$1".mnt.tmp
mount -t btrfs "$1" "$1".mnt.tmp
result=$?
if [ $result = 0 ]; then
shrink "$1".mnt.tmp
result=$?
fi
umount "$1".mnt.tmp
rmdir "$1".mnt.tmp
btrfs_truncate "$1"
return $result
else
die "not a file or directory: $1"
fi
}
main "$@"
|
