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-rw-r--r--src/block/layout.rs56
1 files changed, 33 insertions, 23 deletions
diff --git a/src/block/layout.rs b/src/block/layout.rs
index 3b529fc0..19b6fa17 100644
--- a/src/block/layout.rs
+++ b/src/block/layout.rs
@@ -11,25 +11,28 @@ type Idx = u16;
const DRIVE_NPART: usize = 1024;
-const DPART_BYTES: (usize, usize) = (2, 3);
+const HASH_DRIVE_BYTES: (usize, usize) = (2, 3);
#[derive(Serialize, Deserialize, Debug, Clone)]
pub(crate) struct DataLayout {
pub(crate) data_dirs: Vec<DataDir>,
/// Primary storage location (index in data_dirs) for each partition
+ /// = the location where the data is supposed to be, blocks are always
+ /// written there (copies in other dirs may be deleted if they exist)
pub(crate) part_prim: Vec<Idx>,
- /// Secondary storage locations for each partition
+ /// Secondary storage locations for each partition = locations
+ /// where data blocks might be, we check from these dirs when reading
pub(crate) part_sec: Vec<Vec<Idx>>,
}
-#[derive(Serialize, Deserialize, Debug, Clone)]
+#[derive(Serialize, Deserialize, Debug, Clone, Eq, PartialEq)]
pub(crate) struct DataDir {
pub(crate) path: PathBuf,
pub(crate) state: DataDirState,
}
-#[derive(Serialize, Deserialize, Debug, Clone, Copy)]
+#[derive(Serialize, Deserialize, Debug, Clone, Copy, Eq, PartialEq)]
pub(crate) enum DataDirState {
Active { capacity: u64 },
ReadOnly,
@@ -55,8 +58,9 @@ impl DataLayout {
assert_eq!(cum_cap, total_cap);
assert_eq!(part_prim.len(), DRIVE_NPART);
- // If any of the storage locations is non-empty, add it as a secondary
- // storage location for all partitions
+ // If any of the storage locations is non-empty, it probably existed before
+ // this algorithm was added, so add it as a secondary storage location for all partitions
+ // to make sure existing files are not lost
let mut part_sec = vec![vec![]; DRIVE_NPART];
for (i, dd) in data_dirs.iter().enumerate() {
if dir_not_empty(&dd.path)? {
@@ -75,10 +79,14 @@ impl DataLayout {
})
}
- pub(crate) fn update(&mut self, dirs: &DataDirEnum) -> Result<Self, Error> {
- // Compute list of new data directories and mapping of old indices
- // to new indices
+ pub(crate) fn update(&mut self, dirs: &DataDirEnum) -> Result<(), Error> {
+ // Make list of new data directories, exit if nothing changed
let data_dirs = make_data_dirs(dirs)?;
+ if data_dirs == self.data_dirs {
+ return Ok(());
+ }
+
+ // Compute mapping of old indices to new indices
let old2new = self
.data_dirs
.iter()
@@ -114,15 +122,13 @@ impl DataLayout {
// Compute the target number of partitions per data directory
let total_cap = data_dirs.iter().filter_map(|x| x.capacity()).sum::<u64>();
let mut cum_cap = 0;
- let mut npart_per_dir = vec![];
- for dd in data_dirs.iter() {
+ let mut npart_per_dir = vec![0; data_dirs.len()];
+ for (idir, dd) in data_dirs.iter().enumerate() {
if let DataDirState::Active { capacity } = dd.state {
let begin = (cum_cap * DRIVE_NPART as u64) / total_cap;
cum_cap += capacity;
let end = (cum_cap * DRIVE_NPART as u64) / total_cap;
- npart_per_dir.push((end - begin) as usize);
- } else {
- npart_per_dir.push(0);
+ npart_per_dir[idir] = (end - begin) as usize;
}
}
assert_eq!(cum_cap, total_cap);
@@ -161,11 +167,14 @@ impl DataLayout {
// add partitions from unassigned
for (idir, (parts, tgt_npart)) in dir_prim.iter_mut().zip(npart_per_dir.iter()).enumerate()
{
- assert!(unassigned.len() >= *tgt_npart - parts.len());
- for _ in parts.len()..*tgt_npart {
- let new_part = unassigned.pop().unwrap();
- part_prim[new_part] = Some(idir as Idx);
- part_sec[new_part].retain(|x| *x != idir as Idx);
+ if parts.len() < *tgt_npart {
+ let required = *tgt_npart - parts.len();
+ assert!(unassigned.len() >= required);
+ for _ in 0..required {
+ let new_part = unassigned.pop().unwrap();
+ part_prim[new_part] = Some(idir as Idx);
+ part_sec[new_part].retain(|x| *x != idir as Idx);
+ }
}
}
@@ -183,11 +192,12 @@ impl DataLayout {
.unwrap_or(0)
> 0));
- Ok(Self {
+ *self = Self {
data_dirs,
part_prim,
part_sec,
- })
+ };
+ Ok(())
}
pub(crate) fn primary_block_dir(&self, hash: &Hash) -> PathBuf {
@@ -208,8 +218,8 @@ impl DataLayout {
fn partition_from(&self, hash: &Hash) -> usize {
u16::from_be_bytes([
- hash.as_slice()[DPART_BYTES.0],
- hash.as_slice()[DPART_BYTES.1],
+ hash.as_slice()[HASH_DRIVE_BYTES.0],
+ hash.as_slice()[HASH_DRIVE_BYTES.1],
]) as usize % DRIVE_NPART
}