diff options
Diffstat (limited to 'src/block')
| -rw-r--r-- | src/block/layout.rs | 56 |
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 } |