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Message-Id: <20240514131711.379322-31-wedsonaf@gmail.com>
Date: Tue, 14 May 2024 10:17:11 -0300
From: Wedson Almeida Filho <wedsonaf@...il.com>
To: Alexander Viro <viro@...iv.linux.org.uk>,
Christian Brauner <brauner@...nel.org>,
Matthew Wilcox <willy@...radead.org>,
Dave Chinner <david@...morbit.com>
Cc: Kent Overstreet <kent.overstreet@...il.com>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
linux-fsdevel@...r.kernel.org,
rust-for-linux@...r.kernel.org,
linux-kernel@...r.kernel.org,
Wedson Almeida Filho <walmeida@...rosoft.com>
Subject: [RFC PATCH v2 30/30] WIP: fs: ext2: add rust ro ext2 implementation
From: Wedson Almeida Filho <walmeida@...rosoft.com>
Signed-off-by: Wedson Almeida Filho <walmeida@...rosoft.com>
---
fs/Kconfig | 1 +
fs/Makefile | 1 +
fs/rust-ext2/Kconfig | 13 +
fs/rust-ext2/Makefile | 8 +
fs/rust-ext2/defs.rs | 173 +++++++++++++
fs/rust-ext2/ext2.rs | 551 ++++++++++++++++++++++++++++++++++++++++++
rust/kernel/lib.rs | 3 +
7 files changed, 750 insertions(+)
create mode 100644 fs/rust-ext2/Kconfig
create mode 100644 fs/rust-ext2/Makefile
create mode 100644 fs/rust-ext2/defs.rs
create mode 100644 fs/rust-ext2/ext2.rs
diff --git a/fs/Kconfig b/fs/Kconfig
index 2cbd99d6784c..cf0cac5c5b1e 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -338,6 +338,7 @@ source "fs/ufs/Kconfig"
source "fs/erofs/Kconfig"
source "fs/vboxsf/Kconfig"
source "fs/tarfs/Kconfig"
+source "fs/rust-ext2/Kconfig"
endif # MISC_FILESYSTEMS
diff --git a/fs/Makefile b/fs/Makefile
index d8bbda73e3a9..c1a3007efc7d 100644
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -130,3 +130,4 @@ obj-$(CONFIG_EROFS_FS) += erofs/
obj-$(CONFIG_VBOXSF_FS) += vboxsf/
obj-$(CONFIG_ZONEFS_FS) += zonefs/
obj-$(CONFIG_TARFS_FS) += tarfs/
+obj-$(CONFIG_RUST_EXT2_FS) += rust-ext2/
diff --git a/fs/rust-ext2/Kconfig b/fs/rust-ext2/Kconfig
new file mode 100644
index 000000000000..976371655ca6
--- /dev/null
+++ b/fs/rust-ext2/Kconfig
@@ -0,0 +1,13 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+
+config RUST_EXT2_FS
+ tristate "Rust second extended fs support"
+ depends on RUST && BLOCK
+ help
+ Ext2 is a standard Linux file system for hard disks.
+
+ To compile this file system support as a module, choose M here: the
+ module will be called rust_ext2.
+
+ If unsure, say Y.
diff --git a/fs/rust-ext2/Makefile b/fs/rust-ext2/Makefile
new file mode 100644
index 000000000000..ac960b5f89d7
--- /dev/null
+++ b/fs/rust-ext2/Makefile
@@ -0,0 +1,8 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for the linux tarfs filesystem routines.
+#
+
+obj-$(CONFIG_RUST_EXT2_FS) += rust_ext2.o
+
+rust_ext2-y := ext2.o
diff --git a/fs/rust-ext2/defs.rs b/fs/rust-ext2/defs.rs
new file mode 100644
index 000000000000..5f84852b4961
--- /dev/null
+++ b/fs/rust-ext2/defs.rs
@@ -0,0 +1,173 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Definitions of tarfs structures.
+
+use kernel::types::LE;
+
+pub(crate) const EXT2_SUPER_MAGIC: u16 = 0xEF53;
+
+pub(crate) const EXT2_MAX_BLOCK_LOG_SIZE: u32 = 16;
+
+pub(crate) const EXT2_GOOD_OLD_REV: u32 = 0; /* The good old (original) format */
+pub(crate) const EXT2_DYNAMIC_REV: u32 = 1; /* V2 format w/ dynamic inode sizes */
+
+pub(crate) const EXT2_GOOD_OLD_INODE_SIZE: u16 = 128;
+
+pub(crate) const EXT2_ROOT_INO: u32 = 2; /* Root inode */
+
+/* First non-reserved inode for old ext2 filesystems. */
+pub(crate) const EXT2_GOOD_OLD_FIRST_INO: u32 = 11;
+
+pub(crate) const EXT2_FEATURE_INCOMPAT_FILETYPE: u32 = 0x0002;
+
+/*
+ * Constants relative to the data blocks
+ */
+pub(crate) const EXT2_NDIR_BLOCKS: usize = 12;
+pub(crate) const EXT2_IND_BLOCK: usize = EXT2_NDIR_BLOCKS;
+pub(crate) const EXT2_DIND_BLOCK: usize = EXT2_IND_BLOCK + 1;
+pub(crate) const EXT2_TIND_BLOCK: usize = EXT2_DIND_BLOCK + 1;
+pub(crate) const EXT2_N_BLOCKS: usize = EXT2_TIND_BLOCK + 1;
+
+kernel::derive_readable_from_bytes! {
+ #[repr(C)]
+ pub(crate) struct Super {
+ pub(crate) inodes_count: LE<u32>,
+ pub(crate) blocks_count: LE<u32>,
+ pub(crate) r_blocks_count: LE<u32>,
+ pub(crate) free_blocks_count: LE<u32>, /* Free blocks count */
+ pub(crate) free_inodes_count: LE<u32>, /* Free inodes count */
+ pub(crate) first_data_block: LE<u32>, /* First Data Block */
+ pub(crate) log_block_size: LE<u32>, /* Block size */
+ pub(crate) log_frag_size: LE<u32>, /* Fragment size */
+ pub(crate) blocks_per_group: LE<u32>, /* # Blocks per group */
+ pub(crate) frags_per_group: LE<u32>, /* # Fragments per group */
+ pub(crate) inodes_per_group: LE<u32>, /* # Inodes per group */
+ pub(crate) mtime: LE<u32>, /* Mount time */
+ pub(crate) wtime: LE<u32>, /* Write time */
+ pub(crate) mnt_count: LE<u16>, /* Mount count */
+ pub(crate) max_mnt_count: LE<u16>, /* Maximal mount count */
+ pub(crate) magic: LE<u16>, /* Magic signature */
+ pub(crate) state: LE<u16>, /* File system state */
+ pub(crate) errors: LE<u16>, /* Behaviour when detecting errors */
+ pub(crate) minor_rev_level: LE<u16>, /* minor revision level */
+ pub(crate) lastcheck: LE<u32>, /* time of last check */
+ pub(crate) checkinterval: LE<u32>, /* max. time between checks */
+ pub(crate) creator_os: LE<u32>, /* OS */
+ pub(crate) rev_level: LE<u32>, /* Revision level */
+ pub(crate) def_resuid: LE<u16>, /* Default uid for reserved blocks */
+ pub(crate) def_resgid: LE<u16>, /* Default gid for reserved blocks */
+ /*
+ * These fields are for EXT2_DYNAMIC_REV superblocks only.
+ *
+ * Note: the difference between the compatible feature set and
+ * the incompatible feature set is that if there is a bit set
+ * in the incompatible feature set that the kernel doesn't
+ * know about, it should refuse to mount the filesystem.
+ *
+ * e2fsck's requirements are more strict; if it doesn't know
+ * about a feature in either the compatible or incompatible
+ * feature set, it must abort and not try to meddle with
+ * things it doesn't understand...
+ */
+ pub(crate) first_ino: LE<u32>, /* First non-reserved inode */
+ pub(crate) inode_size: LE<u16>, /* size of inode structure */
+ pub(crate) block_group_nr: LE<u16>, /* block group # of this superblock */
+ pub(crate) feature_compat: LE<u32>, /* compatible feature set */
+ pub(crate) feature_incompat: LE<u32>, /* incompatible feature set */
+ pub(crate) feature_ro_compat: LE<u32>, /* readonly-compatible feature set */
+ pub(crate) uuid: [u8; 16], /* 128-bit uuid for volume */
+ pub(crate) volume_name: [u8; 16], /* volume name */
+ pub(crate) last_mounted: [u8; 64], /* directory where last mounted */
+ pub(crate) algorithm_usage_bitmap: LE<u32>, /* For compression */
+ /*
+ * Performance hints. Directory preallocation should only
+ * happen if the EXT2_COMPAT_PREALLOC flag is on.
+ */
+ pub(crate) prealloc_blocks: u8, /* Nr of blocks to try to preallocate*/
+ pub(crate) prealloc_dir_blocks: u8, /* Nr to preallocate for dirs */
+ padding1: u16,
+ /*
+ * Journaling support valid if EXT3_FEATURE_COMPAT_HAS_JOURNAL set.
+ */
+ pub(crate) journal_uuid: [u8; 16], /* uuid of journal superblock */
+ pub(crate) journal_inum: u32, /* inode number of journal file */
+ pub(crate) journal_dev: u32, /* device number of journal file */
+ pub(crate) last_orphan: u32, /* start of list of inodes to delete */
+ pub(crate) hash_seed: [u32; 4], /* HTREE hash seed */
+ pub(crate) def_hash_version: u8, /* Default hash version to use */
+ pub(crate) reserved_char_pad: u8,
+ pub(crate) reserved_word_pad: u16,
+ pub(crate) default_mount_opts: LE<u32>,
+ pub(crate) first_meta_bg: LE<u32>, /* First metablock block group */
+ reserved: [u32; 190], /* Padding to the end of the block */
+ }
+
+ #[repr(C)]
+ #[derive(Clone, Copy)]
+ pub(crate) struct Group {
+ /// Blocks bitmap block.
+ pub block_bitmap: LE<u32>,
+
+ /// Inodes bitmap block.
+ pub inode_bitmap: LE<u32>,
+
+ /// Inodes table block.
+ pub inode_table: LE<u32>,
+
+ /// Number of free blocks.
+ pub free_blocks_count: LE<u16>,
+
+ /// Number of free inodes.
+ pub free_inodes_count: LE<u16>,
+
+ /// Number of directories.
+ pub used_dirs_count: LE<u16>,
+
+ pad: LE<u16>,
+ reserved: [u32; 3],
+ }
+
+ #[repr(C)]
+ pub(crate) struct INode {
+ pub mode: LE<u16>, /* File mode */
+ pub uid: LE<u16>, /* Low 16 bits of Owner Uid */
+ pub size: LE<u32>, /* Size in bytes */
+ pub atime: LE<u32>, /* Access time */
+ pub ctime: LE<u32>, /* Creation time */
+ pub mtime: LE<u32>, /* Modification time */
+ pub dtime: LE<u32>, /* Deletion Time */
+ pub gid: LE<u16>, /* Low 16 bits of Group Id */
+ pub links_count: LE<u16>, /* Links count */
+ pub blocks: LE<u32>, /* Blocks count */
+ pub flags: LE<u32>, /* File flags */
+ pub reserved1: LE<u32>,
+ pub block: [LE<u32>; EXT2_N_BLOCKS],/* Pointers to blocks */
+ pub generation: LE<u32>, /* File version (for NFS) */
+ pub file_acl: LE<u32>, /* File ACL */
+ pub dir_acl: LE<u32>, /* Directory ACL */
+ pub faddr: LE<u32>, /* Fragment address */
+ pub frag: u8, /* Fragment number */
+ pub fsize: u8, /* Fragment size */
+ pub pad1: LE<u16>,
+ pub uid_high: LE<u16>,
+ pub gid_high: LE<u16>,
+ pub reserved2: LE<u32>,
+ }
+
+ #[repr(C)]
+ pub(crate) struct DirEntry {
+ pub(crate) inode: LE<u32>, /* Inode number */
+ pub(crate) rec_len: LE<u16>, /* Directory entry length */
+ pub(crate) name_len: u8, /* Name length */
+ pub(crate) file_type: u8, /* Only if the "filetype" feature flag is set. */
+ }
+}
+
+pub(crate) const FT_REG_FILE: u8 = 1;
+pub(crate) const FT_DIR: u8 = 2;
+pub(crate) const FT_CHRDEV: u8 = 3;
+pub(crate) const FT_BLKDEV: u8 = 4;
+pub(crate) const FT_FIFO: u8 = 5;
+pub(crate) const FT_SOCK: u8 = 6;
+pub(crate) const FT_SYMLINK: u8 = 7;
diff --git a/fs/rust-ext2/ext2.rs b/fs/rust-ext2/ext2.rs
new file mode 100644
index 000000000000..2d6b1e7ca156
--- /dev/null
+++ b/fs/rust-ext2/ext2.rs
@@ -0,0 +1,551 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Ext2 file system.
+
+use alloc::vec::Vec;
+use core::mem::size_of;
+use defs::*;
+use kernel::fs::{
+ self, address_space, dentry, dentry::DEntry, file, file::File, inode, inode::INode, iomap, sb,
+ sb::SuperBlock, Offset,
+};
+use kernel::types::{ARef, Either, FromBytes, Locked, LE};
+use kernel::{block, c_str, prelude::*, str::CString, time::Timespec, user, PAGE_SIZE};
+
+pub mod defs;
+
+kernel::module_fs! {
+ type: Ext2Fs,
+ name: "ext2",
+ author: "Wedson Almeida Filho <walmeida@...rosoft.com>",
+ description: "ext2 file system",
+ license: "GPL",
+}
+
+const SB_OFFSET: Offset = 1024;
+
+struct INodeData {
+ data_blocks: [u32; defs::EXT2_N_BLOCKS],
+}
+
+struct Ext2Fs {
+ mapper: inode::Mapper,
+ block_size: u32,
+ has_file_type: bool,
+ _block_size_bits: u32,
+ inodes_per_block: u32,
+ inodes_per_group: u32,
+ inode_count: u32,
+ inode_size: u16,
+ first_ino: u32,
+ group: Vec<defs::Group>,
+}
+
+impl Ext2Fs {
+ fn iget(sb: &SuperBlock<Self>, ino: u32) -> Result<ARef<INode<Self>>> {
+ let s = sb.data();
+ if (ino != EXT2_ROOT_INO && ino < s.first_ino) || ino > s.inode_count {
+ return Err(ENOENT);
+ }
+ let group = ((ino - 1) / s.inodes_per_group) as usize;
+ let offset = (ino - 1) % s.inodes_per_group;
+
+ if group >= s.group.len() {
+ return Err(ENOENT);
+ }
+
+ // Create an inode or find an existing (cached) one.
+ let mut inode = match sb.get_or_create_inode(ino.into())? {
+ Either::Left(existing) => return Ok(existing),
+ Either::Right(new) => new,
+ };
+
+ let inodes_block = Offset::from(s.group[group].inode_table.value());
+ let inode_block = inodes_block + Offset::from(offset / s.inodes_per_block);
+ let offset = (offset % s.inodes_per_block) as usize;
+ let b = sb
+ .data()
+ .mapper
+ .mapped_folio(inode_block * Offset::from(s.block_size))?;
+ let idata = defs::INode::from_bytes(&b, offset * s.inode_size as usize).ok_or(EIO)?;
+ let mode = idata.mode.value();
+
+ if idata.links_count.value() == 0 && (mode == 0 || idata.dtime.value() != 0) {
+ return Err(ESTALE);
+ }
+
+ const DIR_FOPS: file::Ops<Ext2Fs> = file::Ops::new::<Ext2Fs>();
+ const DIR_IOPS: inode::Ops<Ext2Fs> = inode::Ops::new::<Ext2Fs>();
+ const FILE_AOPS: address_space::Ops<Ext2Fs> = iomap::ro_aops::<Ext2Fs>();
+
+ let mut size = idata.size.value().into();
+ let typ = match mode & fs::mode::S_IFMT {
+ fs::mode::S_IFREG => {
+ size |= Offset::from(idata.dir_acl.value())
+ .checked_shl(32)
+ .ok_or(EUCLEAN)?;
+ inode
+ .set_aops(FILE_AOPS)
+ .set_fops(file::Ops::generic_ro_file());
+ inode::Type::Reg
+ }
+ fs::mode::S_IFDIR => {
+ inode
+ .set_iops(DIR_IOPS)
+ .set_fops(DIR_FOPS)
+ .set_aops(FILE_AOPS);
+ inode::Type::Dir
+ }
+ fs::mode::S_IFLNK => {
+ if idata.blocks.value() == 0 {
+ const OFFSET: usize = core::mem::offset_of!(defs::INode, block);
+ let name = &b[offset * usize::from(s.inode_size) + OFFSET..];
+ let name_len = size as usize;
+ if name_len > name.len() || name_len == 0 {
+ return Err(EIO);
+ }
+ inode.set_iops(inode::Ops::simple_symlink_inode());
+ inode::Type::Lnk(Some(CString::try_from(&name[..name_len])?))
+ } else {
+ inode
+ .set_aops(FILE_AOPS)
+ .set_iops(inode::Ops::page_symlink_inode());
+ inode::Type::Lnk(None)
+ }
+ }
+ fs::mode::S_IFSOCK => inode::Type::Sock,
+ fs::mode::S_IFIFO => inode::Type::Fifo,
+ fs::mode::S_IFCHR => {
+ let (major, minor) = decode_dev(&idata.block);
+ inode::Type::Chr(major, minor)
+ }
+ fs::mode::S_IFBLK => {
+ let (major, minor) = decode_dev(&idata.block);
+ inode::Type::Blk(major, minor)
+ }
+ _ => return Err(ENOENT),
+ };
+ inode.init(inode::Params {
+ typ,
+ mode: mode & 0o777,
+ size,
+ blocks: idata.blocks.value().into(),
+ nlink: idata.links_count.value().into(),
+ uid: u32::from(idata.uid.value()) | u32::from(idata.uid_high.value()) << 16,
+ gid: u32::from(idata.gid.value()) | u32::from(idata.gid_high.value()) << 16,
+ ctime: Timespec::new(idata.ctime.value().into(), 0)?,
+ mtime: Timespec::new(idata.mtime.value().into(), 0)?,
+ atime: Timespec::new(idata.atime.value().into(), 0)?,
+ value: INodeData {
+ data_blocks: core::array::from_fn(|i| idata.block[i].value()),
+ },
+ })
+ }
+
+ fn offsets<'a>(&self, mut block: u64, out: &'a mut [u32]) -> Option<&'a [u32]> {
+ let ptrs = u64::from(self.block_size / size_of::<u32>() as u32);
+ let ptr_mask = ptrs - 1;
+ let ptr_bits = ptrs.trailing_zeros();
+
+ if block < EXT2_NDIR_BLOCKS as u64 {
+ out[0] = block as u32;
+ return Some(&out[..1]);
+ }
+
+ block -= EXT2_NDIR_BLOCKS as u64;
+ if block < ptrs {
+ out[0] = EXT2_IND_BLOCK as u32;
+ out[1] = block as u32;
+ return Some(&out[..2]);
+ }
+
+ block -= ptrs;
+ if block < (1 << (2 * ptr_bits)) {
+ out[0] = EXT2_DIND_BLOCK as u32;
+ out[1] = (block >> ptr_bits) as u32;
+ out[2] = (block & ptr_mask) as u32;
+ return Some(&out[..3]);
+ }
+
+ block -= ptrs * ptrs;
+ if block < ptrs * ptrs * ptrs {
+ out[0] = EXT2_TIND_BLOCK as u32;
+ out[1] = (block >> (2 * ptr_bits)) as u32;
+ out[2] = ((block >> ptr_bits) & ptr_mask) as u32;
+ out[3] = (block & ptr_mask) as u32;
+ return Some(&out[..4]);
+ }
+
+ None
+ }
+
+ fn offset_to_block(inode: &INode<Self>, block: Offset) -> Result<u64> {
+ let s = inode.super_block().data();
+ let mut indices = [0u32; 4];
+ let boffsets = s.offsets(block as u64, &mut indices).ok_or(EIO)?;
+ let mut boffset = inode.data().data_blocks[boffsets[0] as usize];
+ let mapper = &s.mapper;
+ for i in &boffsets[1..] {
+ let b = mapper.mapped_folio(Offset::from(boffset) * Offset::from(s.block_size))?;
+ let table = LE::<u32>::from_bytes_to_slice(&b).ok_or(EIO)?;
+ boffset = table[*i as usize].value();
+ }
+ Ok(boffset.into())
+ }
+
+ fn check_descriptors(s: &Super, groups: &[Group]) -> Result {
+ for (i, g) in groups.iter().enumerate() {
+ let first = i as u32 * s.blocks_per_group.value() + s.first_data_block.value();
+ let last = if i == groups.len() - 1 {
+ s.blocks_count.value()
+ } else {
+ first + s.blocks_per_group.value() - 1
+ };
+
+ if g.block_bitmap.value() < first || g.block_bitmap.value() > last {
+ pr_err!(
+ "Block bitmap for group {i} no in group (block {})\n",
+ g.block_bitmap.value()
+ );
+ return Err(EINVAL);
+ }
+
+ if g.inode_bitmap.value() < first || g.inode_bitmap.value() > last {
+ pr_err!(
+ "Inode bitmap for group {i} no in group (block {})\n",
+ g.inode_bitmap.value()
+ );
+ return Err(EINVAL);
+ }
+
+ if g.inode_table.value() < first || g.inode_table.value() > last {
+ pr_err!(
+ "Inode table for group {i} no in group (block {})\n",
+ g.inode_table.value()
+ );
+ return Err(EINVAL);
+ }
+ }
+ Ok(())
+ }
+}
+
+impl fs::FileSystem for Ext2Fs {
+ type Data = Box<Self>;
+ type INodeData = INodeData;
+ const NAME: &'static CStr = c_str!("rust-ext2");
+ const SUPER_TYPE: sb::Type = sb::Type::BlockDev;
+
+ fn fill_super(
+ sb: &mut SuperBlock<Self, sb::New>,
+ mapper: Option<inode::Mapper>,
+ ) -> Result<Self::Data> {
+ let Some(mapper) = mapper else {
+ return Err(EINVAL);
+ };
+
+ if sb.min_blocksize(PAGE_SIZE as i32) == 0 {
+ pr_err!("Unable to set block size\n");
+ return Err(EINVAL);
+ }
+
+ // Map the super block and check the magic number.
+ let mapped = mapper.mapped_folio(SB_OFFSET)?;
+ let s = Super::from_bytes(&mapped, 0).ok_or(EIO)?;
+
+ if s.magic.value() != EXT2_SUPER_MAGIC {
+ return Err(EINVAL);
+ }
+
+ // Check for unsupported flags.
+ let mut has_file_type = false;
+ if s.rev_level.value() >= EXT2_DYNAMIC_REV {
+ let features = s.feature_incompat.value();
+ if features & !EXT2_FEATURE_INCOMPAT_FILETYPE != 0 {
+ pr_err!("Unsupported incompatible feature: {:x}\n", features);
+ return Err(EINVAL);
+ }
+
+ has_file_type = features & EXT2_FEATURE_INCOMPAT_FILETYPE != 0;
+
+ let features = s.feature_ro_compat.value();
+ if !sb.rdonly() && features != 0 {
+ pr_err!("Unsupported rw incompatible feature: {:x}\n", features);
+ return Err(EINVAL);
+ }
+ }
+
+ // Set the block size.
+ let block_size_bits = s.log_block_size.value();
+ if block_size_bits > EXT2_MAX_BLOCK_LOG_SIZE - 10 {
+ pr_err!("Invalid log block size: {}\n", block_size_bits);
+ return Err(EINVAL);
+ }
+
+ let block_size = 1024u32 << block_size_bits;
+ if sb.min_blocksize(block_size as i32) != block_size as i32 {
+ pr_err!("Bad block size: {}\n", block_size);
+ return Err(ENXIO);
+ }
+
+ // Get the first inode and the inode size.
+ let (inode_size, first_ino) = if s.rev_level.value() == EXT2_GOOD_OLD_REV {
+ (EXT2_GOOD_OLD_INODE_SIZE, EXT2_GOOD_OLD_FIRST_INO)
+ } else {
+ let size = s.inode_size.value();
+ if size < EXT2_GOOD_OLD_INODE_SIZE
+ || !size.is_power_of_two()
+ || u32::from(size) > block_size
+ {
+ pr_err!("Unsupported inode size: {}\n", size);
+ return Err(EINVAL);
+ }
+ (size, s.first_ino.value())
+ };
+
+ // Get the number of inodes per group and per block.
+ let inode_count = s.inodes_count.value();
+ let inodes_per_group = s.inodes_per_group.value();
+ let inodes_per_block = block_size / u32::from(inode_size);
+ if inodes_per_group == 0 || inodes_per_block == 0 {
+ return Err(EINVAL);
+ }
+
+ if inodes_per_group > block_size * 8 || inodes_per_group < inodes_per_block {
+ pr_err!("Bad inodes per group: {}\n", inodes_per_group);
+ return Err(EINVAL);
+ }
+
+ // Check the size of the groups.
+ let itb_per_group = inodes_per_group / inodes_per_block;
+ let blocks_per_group = s.blocks_per_group.value();
+ if blocks_per_group > block_size * 8 || blocks_per_group <= itb_per_group + 3 {
+ pr_err!("Bad blocks per group: {}\n", blocks_per_group);
+ return Err(EINVAL);
+ }
+
+ let blocks_count = s.blocks_count.value();
+ if block::Sector::from(blocks_count) > sb.sector_count() >> (1 + block_size_bits) {
+ pr_err!(
+ "Block count ({blocks_count}) exceeds size of device ({})\n",
+ sb.sector_count() >> (1 + block_size_bits)
+ );
+ return Err(EINVAL);
+ }
+
+ let group_count = (blocks_count - s.first_data_block.value() - 1) / blocks_per_group + 1;
+ if group_count * inodes_per_group != inode_count {
+ pr_err!(
+ "Unexpected inode count: {inode_count} vs {}",
+ group_count * inodes_per_group
+ );
+ return Err(EINVAL);
+ }
+
+ let mut groups = Vec::new();
+ groups.reserve(group_count as usize, GFP_NOFS)?;
+
+ let mut remain = group_count;
+ let mut offset = (SB_OFFSET / Offset::from(block_size) + 1) * Offset::from(block_size);
+ while remain > 0 {
+ let b = mapper.mapped_folio(offset)?;
+ for g in Group::from_bytes_to_slice(&b).ok_or(EIO)? {
+ groups.push(*g, GFP_NOFS)?;
+ remain -= 1;
+ if remain == 0 {
+ break;
+ }
+ }
+ offset += Offset::try_from(b.len())?;
+ }
+
+ Self::check_descriptors(s, &groups)?;
+
+ sb.set_magic(s.magic.value().into());
+ drop(mapped);
+ Ok(Box::new(
+ Ext2Fs {
+ mapper,
+ block_size,
+ _block_size_bits: block_size_bits,
+ has_file_type,
+ inodes_per_group,
+ inodes_per_block,
+ inode_count,
+ inode_size,
+ first_ino,
+ group: groups,
+ },
+ GFP_KERNEL,
+ )?)
+ }
+
+ fn init_root(sb: &SuperBlock<Self>) -> Result<dentry::Root<Self>> {
+ let inode = Self::iget(sb, EXT2_ROOT_INO)?;
+ dentry::Root::try_new(inode)
+ }
+}
+
+fn rec_len(d: &DirEntry) -> u32 {
+ let len = d.rec_len.value();
+
+ if PAGE_SIZE >= 65536 && len == u16::MAX {
+ 1u32 << 16
+ } else {
+ len.into()
+ }
+}
+
+#[vtable]
+impl file::Operations for Ext2Fs {
+ type FileSystem = Self;
+
+ fn seek(file: &File<Self>, offset: Offset, whence: file::Whence) -> Result<Offset> {
+ file::generic_seek(file, offset, whence)
+ }
+
+ fn read(_: &File<Self>, _: &mut user::Writer, _: &mut Offset) -> Result<usize> {
+ Err(EISDIR)
+ }
+
+ fn read_dir(
+ _file: &File<Self>,
+ inode: &Locked<&INode<Self>, inode::ReadSem>,
+ emitter: &mut file::DirEmitter,
+ ) -> Result {
+ let has_file_type = inode.super_block().data().has_file_type;
+
+ inode.for_each_page(emitter.pos(), Offset::MAX, |data| {
+ let mut offset = 0usize;
+ let mut acc: Offset = 0;
+ let limit = data.len().saturating_sub(size_of::<DirEntry>());
+ while offset < limit {
+ let dirent = DirEntry::from_bytes(data, offset).ok_or(EIO)?;
+ offset += size_of::<DirEntry>();
+
+ let name_len = usize::from(dirent.name_len);
+ if data.len() - offset < name_len {
+ return Err(EIO);
+ }
+
+ let name = &data[offset..][..name_len];
+ let rec_len = rec_len(dirent);
+ offset = offset - size_of::<DirEntry>() + rec_len as usize;
+ if rec_len == 0 || offset > data.len() {
+ return Err(EIO);
+ }
+
+ acc += Offset::from(rec_len);
+ let ino = dirent.inode.value();
+ if ino == 0 {
+ continue;
+ }
+
+ let t = if !has_file_type {
+ file::DirEntryType::Unknown
+ } else {
+ match dirent.file_type {
+ FT_REG_FILE => file::DirEntryType::Reg,
+ FT_DIR => file::DirEntryType::Dir,
+ FT_SYMLINK => file::DirEntryType::Lnk,
+ FT_CHRDEV => file::DirEntryType::Chr,
+ FT_BLKDEV => file::DirEntryType::Blk,
+ FT_FIFO => file::DirEntryType::Fifo,
+ FT_SOCK => file::DirEntryType::Sock,
+ _ => continue,
+ }
+ };
+
+ if !emitter.emit(acc, name, ino.into(), t) {
+ return Ok(Some(()));
+ }
+ acc = 0;
+ }
+ Ok(None)
+ })?;
+ Ok(())
+ }
+}
+
+#[vtable]
+impl inode::Operations for Ext2Fs {
+ type FileSystem = Self;
+
+ fn lookup(
+ parent: &Locked<&INode<Self>, inode::ReadSem>,
+ dentry: dentry::Unhashed<'_, Self>,
+ ) -> Result<Option<ARef<DEntry<Self>>>> {
+ let inode = parent.for_each_page(0, Offset::MAX, |data| {
+ let mut offset = 0usize;
+ while data.len() - offset > size_of::<DirEntry>() {
+ let dirent = DirEntry::from_bytes(data, offset).ok_or(EIO)?;
+ offset += size_of::<DirEntry>();
+
+ let name_len = usize::from(dirent.name_len);
+ if data.len() - offset < name_len {
+ return Err(EIO);
+ }
+
+ let name = &data[offset..][..name_len];
+
+ offset = offset - size_of::<DirEntry>() + usize::from(dirent.rec_len.value());
+ if offset > data.len() {
+ return Err(EIO);
+ }
+
+ let ino = dirent.inode.value();
+ if ino != 0 && name == dentry.name() {
+ return Ok(Some(Self::iget(parent.super_block(), ino)?));
+ }
+ }
+ Ok(None)
+ })?;
+
+ dentry.splice_alias(inode)
+ }
+}
+
+impl iomap::Operations for Ext2Fs {
+ type FileSystem = Self;
+
+ fn begin<'a>(
+ inode: &'a INode<Self>,
+ pos: Offset,
+ length: Offset,
+ _flags: u32,
+ map: &mut iomap::Map<'a>,
+ _srcmap: &mut iomap::Map<'a>,
+ ) -> Result {
+ let size = inode.size();
+ if pos >= size {
+ map.set_offset(pos)
+ .set_length(length.try_into()?)
+ .set_flags(iomap::map_flags::MERGED)
+ .set_type(iomap::Type::Hole);
+ return Ok(());
+ }
+
+ let block_size = inode.super_block().data().block_size as Offset;
+ let block = pos / block_size;
+
+ let boffset = Self::offset_to_block(inode, block)?;
+ map.set_offset(block * block_size)
+ .set_length(block_size as u64)
+ .set_flags(iomap::map_flags::MERGED)
+ .set_type(iomap::Type::Mapped)
+ .set_bdev(Some(inode.super_block().bdev()))
+ .set_addr(boffset * block_size as u64);
+
+ Ok(())
+ }
+}
+
+fn decode_dev(block: &[LE<u32>]) -> (u32, u32) {
+ let v = block[0].value();
+ if v != 0 {
+ ((v >> 8) & 255, v & 255)
+ } else {
+ let v = block[1].value();
+ ((v & 0xfff00) >> 8, (v & 0xff) | ((v >> 12) & 0xfff00))
+ }
+}
diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs
index 445599d4bff6..732bc9939f7f 100644
--- a/rust/kernel/lib.rs
+++ b/rust/kernel/lib.rs
@@ -165,3 +165,6 @@ macro_rules! container_of {
ptr.wrapping_sub(offset) as *const $type
}}
}
+
+/// The size in bytes of a page of memory.
+pub const PAGE_SIZE: usize = bindings::PAGE_SIZE;
--
2.34.1
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