proxmox-backup/src/backup/image_index.rs

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Rust
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use failure::*;
use super::chunk_store::*;
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use std::io::Write;
use std::path::{Path, PathBuf};
use std::os::unix::io::AsRawFd;
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use uuid::Uuid;
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#[repr(C)]
pub struct ImageIndexHeader {
pub magic: [u8; 12],
pub version: u32,
pub uuid: [u8; 16],
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pub ctime: u64,
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pub size: u64,
reserved: [u8; 4048], // oversall size is one page (4096 bytes)
}
// split image into fixed size chunks
pub struct ImageIndex<'a> {
store: &'a mut ChunkStore,
chunk_size: usize,
size: usize,
index: *mut u8,
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uuid: [u8; 16],
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ctime: u64,
}
impl <'a> ImageIndex<'a> {
pub fn create(store: &'a mut ChunkStore, path: &Path, size: usize) -> Result<Self, Error> {
let full_path = store.relative_path(path);
println!("FULLPATH: {:?} {}", full_path, size);
let mut file = std::fs::OpenOptions::new()
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.create(true).truncate(true)
.read(true)
.write(true)
.open(&full_path)?;
let chunk_size = 64*1024;
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let header_size = std::mem::size_of::<ImageIndexHeader>();
// todo: use static assertion when available in rust
if header_size != 4096 { panic!("got unexpected header size"); }
let ctime = std::time::SystemTime::now().duration_since(
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std::time::SystemTime::UNIX_EPOCH)?.as_secs();
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let uuid = Uuid::new_v4();
let mut buffer = vec![0u8; header_size];
let header = unsafe { &mut * (buffer.as_ptr() as *mut ImageIndexHeader) };
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header.magic = *b"PROXMOX-IIDX";
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header.version = u32::to_be(1);
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header.ctime = u64::to_be(ctime);
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header.size = u64::to_be(size as u64);
header.uuid = *uuid.as_bytes();
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file.write_all(&buffer)?;
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let index_size = ((size + chunk_size - 1)/chunk_size)*32;
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nix::unistd::ftruncate(file.as_raw_fd(), (header_size + index_size) as i64)?;
println!("SIZES: {} {}", index_size, header_size);
let data = unsafe { nix::sys::mman::mmap(
std::ptr::null_mut(),
index_size,
nix::sys::mman::ProtFlags::PROT_READ | nix::sys::mman::ProtFlags::PROT_WRITE,
nix::sys::mman::MapFlags::MAP_SHARED,
file.as_raw_fd(),
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header_size as i64) }? as *mut u8;
Ok(Self {
store,
chunk_size,
size,
index: data,
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ctime,
uuid: *uuid.as_bytes(),
})
}
// Note: We want to add data out of order, so do not assume and order here.
pub fn add_chunk(&mut self, pos: usize, chunk: &[u8]) -> Result<(), Error> {
let end = pos + chunk.len();
if end > self.size {
bail!("write chunk data exceeds size ({} >= {})", end, self.size);
}
// last chunk can be smaller
if ((end != self.size) && (chunk.len() != self.chunk_size)) ||
(chunk.len() > self.chunk_size) || (chunk.len() == 0) {
bail!("got chunk with wrong length ({} != {}", chunk.len(), self.chunk_size);
}
if pos >= self.size { bail!("add chunk after end ({} >= {})", pos, self.size); }
if pos & (self.chunk_size-1) != 0 { bail!("add unaligned chunk (pos = {})", pos); }
let (is_duplicate, digest) = self.store.insert_chunk(chunk)?;
println!("ADD CHUNK {} {} {} {}", pos, chunk.len(), is_duplicate, u256_to_hex(&digest));
let index_pos = (pos/self.chunk_size)*32;
unsafe {
let dst = self.index.add(index_pos);
dst.copy_from_nonoverlapping(digest.as_ptr(), 32);
}
Ok(())
}
}