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Refactor easy-fs

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This commit is contained in:
Yifan Wu 2021-02-24 03:42:45 +08:00
parent 1c9ce9ca07
commit 2e67eb1db0
14 changed files with 329 additions and 278 deletions
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54
easy-fs/src/bitmap.rs
View file

@ -1,7 +1,9 @@
use alloc::sync::Arc;
use super::BlockDevice;
use super::Dirty;
use super::BLOCK_SZ;
use super::{
BlockDevice,
BLOCK_SZ,
get_block_cache,
};
type BitmapBlock = [u64; 64];
@ -26,41 +28,45 @@ impl Bitmap {
blocks,
}
}
pub fn alloc(&self, block_device: &Arc<dyn BlockDevice>) -> Option<usize> {
for block_id in 0..self.blocks {
let mut dirty_bitmap_block: Dirty<BitmapBlock> = Dirty::new(
let pos = get_block_cache(
block_id + self.start_block_id as usize,
0,
block_device.clone()
);
let bitmap_block = dirty_bitmap_block.get_mut();
if let Some((bits64_pos, inner_pos)) = bitmap_block
.iter()
.enumerate()
.find(|(_, bits64)| **bits64 != u64::MAX)
.map(|(bits64_pos, bits64)| {
(bits64_pos, bits64.trailing_ones() as usize)
}) {
// modify cache
bitmap_block[bits64_pos] |= 1u64 << inner_pos;
return Some(block_id * BLOCK_BITS + bits64_pos * 64 + inner_pos as usize);
// after dirty is dropped, data will be written back automatically
Arc::clone(block_device),
).lock().modify(0, |bitmap_block: &mut BitmapBlock| {
if let Some((bits64_pos, inner_pos)) = bitmap_block
.iter()
.enumerate()
.find(|(_, bits64)| **bits64 != u64::MAX)
.map(|(bits64_pos, bits64)| {
(bits64_pos, bits64.trailing_ones() as usize)
}) {
// modify cache
bitmap_block[bits64_pos] |= 1u64 << inner_pos;
Some(block_id * BLOCK_BITS + bits64_pos * 64 + inner_pos as usize)
} else {
None
}
});
if pos.is_some() {
return pos;
}
}
None
}
pub fn dealloc(&self, block_device: &Arc<dyn BlockDevice>, bit: usize) {
let (block_pos, bits64_pos, inner_pos) = decomposition(bit);
let mut dirty_bitmap_block: Dirty<BitmapBlock> = Dirty::new(
get_block_cache(
block_pos + self.start_block_id,
0,
block_device.clone(),
);
dirty_bitmap_block.modify(|bitmap_block| {
Arc::clone(block_device)
).lock().modify(0, |bitmap_block: &mut BitmapBlock| {
assert!(bitmap_block[bits64_pos] & (1u64 << inner_pos) > 0);
bitmap_block[bits64_pos] -= 1u64 << inner_pos;
});
}
pub fn maximum(&self) -> usize {
self.blocks * BLOCK_BITS
}