[RFC PATCH 10/24] erofs: add device_infos implementation in Rust

Yiyang Wu
2024-09-16T13:56:58Z

Add device_infos implementation in rust. It will later be used
to be put inside the SuperblockInfo. This mask and spec can later
be used to chunk-based image file block mapping.

Signed-off-by: Yiyang Wu <toolmanp@tlmp.cc>
---
fs/erofs/rust/erofs_sys/devices.rs | 47 ++++++++++++++++++++++++++++++
1 file changed, 47 insertions(+)

diff --git a/fs/erofs/rust/erofs_sys/devices.rs b/fs/erofs/rust/erofs_sys/devices.rs
index 097676ee8720..7495164c7bd0 100644
--- a/fs/erofs/rust/erofs_sys/devices.rs
+++ b/fs/erofs/rust/erofs_sys/devices.rs
@@ -1,6 +1,10 @@
// Copyright 2024 Yiyang Wu
// SPDX-License-Identifier: MIT or GPL-2.0-or-later

+use super::alloc_helper::*;
+use super::data::raw_iters::*;
+use super::data::*;
+use super::*;
use alloc::vec::Vec;

/// Device specification.
@@ -21,8 +25,51 @@ pub(crate) struct DeviceSlot {
reserved: [u8; 56],
}

+impl From<[u8; 128]> for DeviceSlot {
+ fn from(data: [u8; 128]) -> Self {
+ Self {
+ tags: data[0..64].try_into().unwrap(),
+ blocks: u32::from_le_bytes([data[64], data[65], data[66], data[67]]),
+ mapped_blocks: u32::from_le_bytes([data[68], data[69], data[70], data[71]]),
+ reserved: data[72..128].try_into().unwrap(),
+ }
+ }
+}
+
/// Device information.
pub(crate) struct DeviceInfo {
pub(crate) mask: u16,
pub(crate) specs: Vec<DeviceSpec>,
}
+
+pub(crate) fn get_device_infos<'a>(
+ iter: &mut (dyn ContinuousBufferIter<'a> + 'a),
+) -> PosixResult<DeviceInfo> {
+ let mut specs = Vec::new();
+ for data in iter {
+ let buffer = data?;
+ let mut cur: usize = 0;
+ let len = buffer.content().len();
+ while cur + 128 <= len {
+ let slot_data: [u8; 128] = buffer.content()[cur..cur + 128].try_into().unwrap();
+ let slot = DeviceSlot::from(slot_data);
+ cur += 128;
+ push_vec(
+ &mut specs,
+ DeviceSpec {
+ tags: slot.tags,
+ blocks: slot.blocks,
+ mapped_blocks: slot.mapped_blocks,
+ },
+ )?;
+ }
+ }
+
+ let mask = if specs.is_empty() {
+ 0
+ } else {
+ (1 << (specs.len().ilog2() + 1)) - 1
+ };
+
+ Ok(DeviceInfo { mask, specs })
+}
--
2.46.0