thin-provisioning-tools/src/shrink/toplevel.rs

501 lines
13 KiB
Rust
Raw Normal View History

use anyhow::Result;
2020-06-25 15:14:57 +05:30
use fixedbitset::{FixedBitSet, IndexRange};
use std::fs::OpenOptions;
use std::io::Write;
use std::os::unix::fs::OpenOptionsExt;
2020-06-25 19:58:45 +05:30
use crate::shrink::copier::{self, Region};
use crate::shrink::xml;
//---------------------------------------
2020-06-25 15:14:57 +05:30
#[derive(Debug)]
struct Pass1 {
// FIXME: Inefficient, use a range_set of some description
allocated_blocks: FixedBitSet,
nr_blocks: u64,
/// High blocks are beyond the new, reduced end of the pool. These
/// will need to be moved.
nr_high_blocks: u64,
block_size: Option<u64>,
2020-06-25 15:14:57 +05:30
}
impl Pass1 {
fn new(nr_blocks: u64) -> Pass1 {
Pass1 {
allocated_blocks: FixedBitSet::with_capacity(0),
nr_blocks,
nr_high_blocks: 0,
block_size: None,
2020-06-25 15:14:57 +05:30
}
}
}
impl xml::MetadataVisitor for Pass1 {
fn superblock_b(&mut self, sb: &xml::Superblock) -> Result<()> {
self.allocated_blocks.grow(sb.nr_data_blocks as usize);
self.block_size = Some(sb.data_block_size as u64);
2020-06-25 15:14:57 +05:30
Ok(())
}
fn superblock_e(&mut self) -> Result<()> {
Ok(())
}
fn device_b(&mut self, _d: &xml::Device) -> Result<()> {
Ok(())
}
fn device_e(&mut self) -> Result<()> {
Ok(())
}
fn map(&mut self, m: &xml::Map) -> Result<()> {
2020-06-25 15:14:57 +05:30
for i in m.data_begin..(m.data_begin + m.len) {
if i > self.nr_blocks {
self.nr_high_blocks += 1;
}
self.allocated_blocks.insert(i as usize);
}
Ok(())
}
fn eof(&mut self) -> Result<()> {
Ok(())
}
}
//---------------------------------------
// Writes remapped xml
struct Pass2<W: Write> {
writer: xml::XmlWriter<W>,
nr_blocks: u64,
remaps: Vec<(BlockRange, BlockRange)>,
}
impl<W: Write> Pass2<W> {
fn new(w: W, nr_blocks: u64, remaps: Vec<(BlockRange, BlockRange)>) -> Pass2<W> {
Pass2 {
writer: xml::XmlWriter::new(w),
nr_blocks,
remaps,
}
}
fn remap(&self, r: BlockRange) -> Vec<BlockRange> {
let mut rmap = Vec::new();
// id
rmap.push(r.clone());
rmap
}
}
impl<W: Write> xml::MetadataVisitor for Pass2<W> {
fn superblock_b(&mut self, sb: &xml::Superblock) -> Result<()> {
self.writer.superblock_b(sb)
}
fn superblock_e(&mut self) -> Result<()> {
self.writer.superblock_e()
}
fn device_b(&mut self, d: &xml::Device) -> Result<()> {
self.writer.device_b(d)
}
fn device_e(&mut self) -> Result<()> {
self.writer.device_e()
}
fn map(&mut self, m: &xml::Map) -> Result<()> {
if m.data_begin + m.len < self.nr_blocks {
// no remapping needed.
self.writer.map(m)?;
} else {
let r = m.data_begin..(m.data_begin + m.len);
let remaps = remap(&r, &self.remaps);
let mut written = 0;
for r in remaps {
self.writer.map(&xml::Map {
thin_begin: m.thin_begin + written,
data_begin: r.start,
time: m.time,
len: range_len(&r),
})?;
written += range_len(&r);
}
}
Ok(())
}
fn eof(&mut self) -> Result<()> {
self.writer.eof()
}
}
//---------------------------------------
2020-06-25 15:14:57 +05:30
type BlockRange = std::ops::Range<u64>;
fn bits_to_ranges(bits: &FixedBitSet) -> Vec<BlockRange> {
let mut ranges = Vec::new();
let mut start = None;
for i in 0..bits.len() {
match (bits[i], start) {
(false, None) => {}
(true, None) => {
start = Some((i as u64, 1));
}
(false, Some((b, len))) => {
ranges.push(b..(b + len));
start = None;
}
(true, Some((b, len))) => {
start = Some((b, len + 1));
}
}
}
if let Some((b, len)) = start {
ranges.push(b..(b + len));
}
ranges
}
// Splits the ranges into those below threshold, and those equal or
// above threshold below threshold, and those equal or above threshold
fn ranges_split(ranges: &Vec<BlockRange>, threshold: u64) -> (Vec<BlockRange>, Vec<BlockRange>) {
use std::ops::Range;
let mut below = Vec::new();
let mut above = Vec::new();
for r in ranges {
match r {
Range { start, end } if *end <= threshold => below.push(*start..*end),
Range { start, end } if *start < threshold => {
below.push(*start..threshold);
above.push(threshold..*end);
}
Range { start, end } => above.push(*start..*end),
}
}
(below, above)
}
fn negate_ranges(ranges: &Vec<BlockRange>) -> Vec<BlockRange> {
use std::ops::Range;
let mut result = Vec::new();
let mut cursor = 0;
for r in ranges {
match r {
Range { start, end } if cursor < *start => {
result.push(cursor..*start);
cursor = *end;
}
Range { start: _, end } => {
cursor = *end;
}
}
}
result
}
fn range_len(r: &BlockRange) -> u64 {
r.end - r.start
}
fn ranges_total(rs: &Vec<BlockRange>) -> u64 {
rs.into_iter().fold(0, |sum, r| sum + range_len(r))
}
// Assumes there is enough space to remap.
fn build_remaps(ranges: Vec<BlockRange>, free: Vec<BlockRange>) -> Vec<(BlockRange, BlockRange)> {
2020-06-25 15:14:57 +05:30
use std::cmp::Ordering;
let mut remap = Vec::new();
let mut range_iter = ranges.into_iter();
let mut free_iter = free.into_iter();
let mut r_ = range_iter.next();
let mut f_ = free_iter.next();
while let (Some(r), Some(f)) = (r_, f_) {
let rlen = range_len(&r);
let flen = range_len(&f);
match rlen.cmp(&flen) {
Ordering::Less => {
// range fits into the free chunk
remap.push((r, f.start..(f.start + rlen)));
f_ = Some((f.start + rlen)..f.end);
r_ = range_iter.next();
}
2020-06-25 15:14:57 +05:30
Ordering::Equal => {
remap.push((r, f));
r_ = range_iter.next();
f_ = free_iter.next();
}
2020-06-25 15:14:57 +05:30
Ordering::Greater => {
remap.push((r.start..(r.start + flen), f));
r_ = Some((r.start + flen)..r.end);
f_ = free_iter.next();
}
}
}
remap
}
fn overlaps(r1: &BlockRange, r2: &BlockRange, index: usize) -> Option<usize> {
if r1.start >= r2.end {
return None;
}
if r2.start >= r1.end {
return None;
}
Some(index)
}
// Finds the index of the first entry that overlaps r.
fn find_first(r: &BlockRange, remaps: &Vec<(BlockRange, BlockRange)>) -> Option<usize> {
if remaps.len() == 0 {
2020-06-25 19:58:45 +05:30
return None;
}
match remaps.binary_search_by_key(&r.start, |(from, _)| from.start) {
Ok(n) => Some(n),
Err(n) => {
if n == 0 {
let (from, _) = &remaps[n];
overlaps(&r, &from, n)
} else if n == remaps.len() {
let (from, _) = &remaps[n - 1];
overlaps(&r, from, n - 1)
} else {
// Need to check the previous entry
let (from, _) = &remaps[n - 1];
overlaps(&r, &from, n - 1).or_else(|| {
let (from, to) = &remaps[n];
overlaps(&r, &from, n)
})
}
}
}
}
fn is_empty(r: &BlockRange) -> bool {
r.start == r.end
}
// remaps must be in sorted order by from.start.
fn remap(r: &BlockRange, remaps: &Vec<(BlockRange, BlockRange)>) -> Vec<BlockRange> {
let mut remap = Vec::new();
let mut r = r.start..r.end;
if let Some(index) = find_first(&r, &remaps) {
let mut index = index;
loop {
let (from, to) = &remaps[index];
// There may be a prefix that doesn't overlap with 'from'
if r.start < from.start {
let len = u64::min(range_len(&r), from.start - r.start);
remap.push(r.start..(r.start + len));
r = (r.start + len)..r.end;
if is_empty(&r) {
break;
}
}
2020-06-25 19:58:45 +05:30
let to = (to.start + (r.start - from.start))..to.end;
let from = r.start..from.end;
let rlen = range_len(&r);
let flen = range_len(&from);
let len = u64::min(rlen, flen);
remap.push(to.start..(to.start + len));
r = (r.start + len)..r.end;
if is_empty(&r) {
break;
}
if len == flen {
index += 1;
}
if index == remaps.len() {
remap.push(r.start..r.end);
break;
}
}
} else {
remap.push(r.start..r.end);
}
remap
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn remap_test() {
struct Test {
remaps: Vec<(BlockRange, BlockRange)>,
input: BlockRange,
output: Vec<BlockRange>,
}
let tests = [
Test {
remaps: vec![],
input: 0..1,
output: vec![0..1],
},
Test {
remaps: vec![],
input: 100..1000,
output: vec![100..1000],
},
Test {
remaps: vec![(10..20, 110..120)],
input: 0..5,
output: vec![0..5],
},
Test {
remaps: vec![(10..20, 110..120)],
input: 10..20,
output: vec![110..120],
},
Test {
remaps: vec![(10..20, 110..120)],
input: 5..15,
output: vec![5..10, 110..115],
},
Test {
remaps: vec![(10..20, 110..120)],
input: 5..25,
output: vec![5..10, 110..120, 20..25],
},
Test {
remaps: vec![(10..20, 110..120)],
input: 15..25,
output: vec![115..120, 20..25],
},
Test {
remaps: vec![(10..20, 110..120)],
input: 25..35,
output: vec![25..35],
},
Test {
remaps: vec![(10..20, 110..120), (30..40, 230..240)],
input: 0..50,
output: vec![0..10, 110..120, 20..30, 230..240, 40..50],
},
];
for t in &tests {
let rs = remap(&t.input, &t.remaps);
assert_eq!(rs, t.output);
}
}
}
fn build_copy_regions(remaps: &Vec<(BlockRange, BlockRange)>, block_size: u64) -> Vec<Region> {
let mut rs = Vec::new();
for (from, to) in remaps {
rs.push(Region {
src: from.start * block_size,
dest: to.start * block_size,
len: range_len(&from) * block_size,
});
}
2020-06-25 19:58:45 +05:30
rs
}
fn process_xml<MV: xml::MetadataVisitor>(input_path: &str, pass: &mut MV) -> Result<()> {
let input = OpenOptions::new()
.read(true)
.write(false)
.custom_flags(libc::O_EXCL)
.open(input_path)?;
xml::read(input, pass)?;
Ok(())
}
2020-06-25 19:58:45 +05:30
pub fn shrink(input_path: &str, output_path: &str, data_path: &str, nr_blocks: u64) -> Result<()> {
2020-06-25 15:14:57 +05:30
let mut pass1 = Pass1::new(nr_blocks);
process_xml(input_path, &mut pass1);
2020-06-25 15:14:57 +05:30
eprintln!("{} blocks need moving", pass1.nr_high_blocks);
let mut free_blocks = 0u64;
for i in 0..pass1.allocated_blocks.len() {
if !pass1.allocated_blocks[i] {
free_blocks += 1;
}
}
eprintln!("{} free blocks below new end.", free_blocks);
let ranges = bits_to_ranges(&pass1.allocated_blocks);
eprintln!("{} allocated ranges:", ranges.len());
eprintln!("{:?}", &ranges);
let (below, above) = ranges_split(&ranges, nr_blocks);
eprintln!("ranges split at {}: ({:?}, {:?})", nr_blocks, below, above);
let free = negate_ranges(&below);
eprintln!("free {:?}.", free);
let nr_moving = ranges_total(&above);
eprintln!("{} blocks need to be remapped.", nr_moving);
let free_blocks = ranges_total(&free);
eprintln!("{} free blocks.", free_blocks);
if free_blocks < nr_moving {
panic!("Insufficient space");
}
let remaps = build_remaps(above, free);
2020-06-25 15:14:57 +05:30
eprintln!("remappings {:?}.", remaps);
let regions = build_copy_regions(&remaps, pass1.block_size.unwrap() as u64);
//eprint!("Copying data...");
copier::copy(data_path, &regions)?;
//eprintln!("done.");
2020-06-25 19:58:45 +05:30
let output = OpenOptions::new()
.read(false)
.write(true)
.create(true)
.open(output_path)?;
let mut pass2 = Pass2::new(output, nr_blocks, remaps);
eprint!("writing new xml...");
process_xml(input_path, &mut pass2)?;
eprintln!("done.");
Ok(())
}
//---------------------------------------