[RFC PATCH 16/24] erofs: implement dir and inode operations in Rust

Yiyang Wu
2024-09-16T13:57:10Z

Implement dir ops and inode ops in Rust.

Signed-off-by: Yiyang Wu <toolmanp@tlmp.cc>
---
fs/erofs/rust/erofs_sys.rs | 1 +
fs/erofs/rust/erofs_sys/data.rs | 4 ++
fs/erofs/rust/erofs_sys/operations.rs | 35 ++++++++++++++++
fs/erofs/rust/erofs_sys/superblock.rs | 59 +++++++++++++++++++++++++++
4 files changed, 99 insertions(+)
create mode 100644 fs/erofs/rust/erofs_sys/operations.rs

diff --git a/fs/erofs/rust/erofs_sys.rs b/fs/erofs/rust/erofs_sys.rs
index 20c0aa81a800..8c08ac347b2b 100644
--- a/fs/erofs/rust/erofs_sys.rs
+++ b/fs/erofs/rust/erofs_sys.rs
@@ -30,6 +30,7 @@
pub(crate) mod errnos;
pub(crate) mod inode;
pub(crate) mod map;
+pub(crate) mod operations;
pub(crate) mod superblock;
pub(crate) mod xattrs;
pub(crate) use errnos::{Errno, Errno::*};
diff --git a/fs/erofs/rust/erofs_sys/data.rs b/fs/erofs/rust/erofs_sys/data.rs
index 21630673c24e..67bb66ce9efb 100644
--- a/fs/erofs/rust/erofs_sys/data.rs
+++ b/fs/erofs/rust/erofs_sys/data.rs
@@ -2,6 +2,7 @@
// SPDX-License-Identifier: MIT or GPL-2.0-or-later
pub(crate) mod backends;
pub(crate) mod raw_iters;
+use super::dir::*;
use super::inode::*;
use super::map::*;
use super::superblock::*;
@@ -26,6 +27,9 @@ pub(crate) trait Backend {
/// DirEntries.
pub(crate) trait Buffer {
fn content(&self) -> &[u8];
+ fn iter_dir(&self) -> DirCollection<'_> {
+ DirCollection::new(self.content())
+ }
}

/// Represents a buffer that holds a reference to a slice of data that
diff --git a/fs/erofs/rust/erofs_sys/operations.rs b/fs/erofs/rust/erofs_sys/operations.rs
new file mode 100644
index 000000000000..070ba20908a2
--- /dev/null
+++ b/fs/erofs/rust/erofs_sys/operations.rs
@@ -0,0 +1,35 @@
+// Copyright 2024 Yiyang Wu
+// SPDX-License-Identifier: MIT or GPL-2.0-or-later
+
+use super::inode::*;
+use super::superblock::*;
+use super::*;
+
+pub(crate) fn read_inode<'a, I, C>(
+ filesystem: &'a dyn FileSystem,
+ collection: &'a mut C,
+ nid: Nid,
+) -> PosixResult<&'a mut I>
+where
+ I: Inode,
+ C: InodeCollection,
+{
+ collection.iget(nid, filesystem)
+}
+
+pub(crate) fn dir_lookup<'a, I, C>(
+ filesystem: &'a dyn FileSystem,
+ collection: &'a mut C,
+ inode: &I,
+ name: &str,
+) -> PosixResult<&'a mut I>
+where
+ I: Inode,
+ C: InodeCollection,
+{
+ filesystem
+ .find_nid(inode, name)?
+ .map_or(Err(Errno::ENOENT), |nid| {
+ read_inode(filesystem, collection, nid)
+ })
+}
diff --git a/fs/erofs/rust/erofs_sys/superblock.rs b/fs/erofs/rust/erofs_sys/superblock.rs
index f60657eff3d6..403ffdeb4573 100644
--- a/fs/erofs/rust/erofs_sys/superblock.rs
+++ b/fs/erofs/rust/erofs_sys/superblock.rs
@@ -8,6 +8,7 @@
use super::data::raw_iters::*;
use super::data::*;
use super::devices::*;
+use super::dir::*;
use super::inode::*;
use super::map::*;
use super::*;
@@ -287,6 +288,64 @@ fn continuous_iter<'a>(
offset: Off,
len: Off,
) -> PosixResult<Box<dyn ContinuousBufferIter<'a> + 'a>>;
+
+ // Inode related goes here.
+ fn read_inode_info(&self, nid: Nid) -> PosixResult<InodeInfo> {
+ (self.as_filesystem(), nid).try_into()
+ }
+
+ fn find_nid(&self, inode: &I, name: &str) -> PosixResult<Option<Nid>> {
+ for buf in self.mapped_iter(inode, 0)? {
+ for dirent in buf?.iter_dir() {
+ if dirent.dirname() == name.as_bytes() {
+ return Ok(Some(dirent.desc.nid));
+ }
+ }
+ }
+ Ok(None)
+ }
+
+ // Readdir related goes here.
+ fn fill_dentries(
+ &self,
+ inode: &I,
+ offset: Off,
+ emitter: &mut dyn FnMut(Dirent<'_>, Off),
+ ) -> PosixResult<()> {
+ let sb = self.superblock();
+ let accessor = sb.blk_access(offset);
+ if offset > inode.info().file_size() {
+ return Err(EUCLEAN);
+ }
+
+ let map_offset = round!(DOWN, offset, sb.blksz());
+ let blk_offset = round!(UP, accessor.off, size_of::<DirentDesc>() as Off);
+
+ let mut map_iter = self.mapped_iter(inode, map_offset)?;
+ let first_buf = map_iter.next().unwrap()?;
+ let mut collection = first_buf.iter_dir();
+
+ let mut pos: Off = map_offset + blk_offset;
+
+ if blk_offset as usize / size_of::<DirentDesc>() <= collection.total() {
+ collection.skip_dir(blk_offset as usize / size_of::<DirentDesc>());
+ for dirent in collection {
+ emitter(dirent, pos);
+ pos += size_of::<DirentDesc>() as Off;
+ }
+ }
+
+ pos = round!(UP, pos, sb.blksz());
+
+ for buf in map_iter {
+ for dirent in buf?.iter_dir() {
+ emitter(dirent, pos);
+ pos += size_of::<DirentDesc>() as Off;
+ }
+ pos = round!(UP, pos, sb.blksz());
+ }
+ Ok(())
+ }
}

pub(crate) struct SuperblockInfo<I, C, T>
--
2.46.0