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|
mod block_device;
mod disk;
mod filesystem;
mod memory;
mod tests;
mod utils;
use clap::Parser;
use fuser::MountOption;
use log::debug;
use std::sync::Arc;
use std::time::Duration;
use crate::disk::block::InodeBlock;
use crate::disk::inode::InodeMode;
use crate::memory::cached_block::BlockCache;
use block_device::{memory_disk::MemoryDisk, BlockDevice, BLOCK_SIZE};
use disk::bitmap::Bitmap;
use disk::block::DataBlock;
use disk::inode::INODE_SIZE;
use users::{get_current_gid, get_current_uid};
#[derive(Parser, Debug)]
#[command(author, version, about)]
struct Args {
mount_point: Option<String>,
#[arg(long)]
auto_unmount: bool,
#[arg(long)]
allow_root: bool,
}
const TTL: Duration = Duration::new(0, 0);
const INODE_PER_BLOCK: usize = BLOCK_SIZE / INODE_SIZE;
/// The design of MyFS is rather simple:
/// +-------------------+
/// | Super Block |
/// +-------------------+
/// | Inode Bitmap |
/// +-------------------+
/// | ... |
/// +-------------------+
/// | Data Block Bitmap |
/// +-------------------+
/// | ... |
/// +-------------------+
/// | Inode Block |
/// +-------------------+
/// | ... |
/// +-------------------+
/// | Data Block |
/// +-------------------+
/// With each block 4KiB, each Inode entry 128B
#[repr(C)]
struct AyaFS {
device: Arc<dyn BlockDevice>,
data_bitmap: Bitmap,
inode_bitmap: Bitmap,
inode_start_block: usize,
data_start_block: usize,
cached_inodes: BlockCache<InodeBlock>,
cached_blocks: BlockCache<DataBlock>,
}
impl AyaFS {
fn new(device: Arc<dyn BlockDevice>, total_block_number: usize) -> Self {
let max_inode_number: usize = 16384; // TODO: remove hard-coded magic number
let inode_block_number = max_inode_number / INODE_PER_BLOCK; // == 128
let inode_bitmap_block_number = (inode_block_number + BLOCK_SIZE - 1) / BLOCK_SIZE;
let blocks_remaining =
total_block_number - inode_block_number - inode_bitmap_block_number - 1;
// let number of data blocks be x, the remaining block number be C,
// the corresponding data bitmap length should be ceil(x / BLK_SIZE),
// thus we have BLK_SIZE * (C-1) / (BLK_SIZE+1) <= x <= BLK_SIZE * C / (BLK_SIZE+1)
// the difference of the two bounds is less than 1,
// meaning only 1 integer could be in between.
// Thus we have x = floor(BLK_SIZE * C / (BLK_SIZE + 1))
let data_block_number = BLOCK_SIZE * blocks_remaining / (BLOCK_SIZE + 1);
let data_bitmap_block_number = blocks_remaining - data_block_number;
debug!("data_bitmap_block_number: {}", data_bitmap_block_number);
debug!("inode_bitmap_block_number: {}", inode_bitmap_block_number);
debug!("inode_block_number: {}", inode_block_number);
debug!("data_block_number: {}", data_block_number);
debug!(
"sum: {}",
1 + data_bitmap_block_number
+ inode_bitmap_block_number
+ inode_block_number
+ data_block_number
);
let mut data_bitmap = Bitmap::new(1, data_bitmap_block_number, device.clone());
let _ = data_bitmap.allocate().unwrap(); // data block 0 is not usable
let mut inode_bitmap = Bitmap::new(
data_bitmap_block_number + 1,
inode_bitmap_block_number,
device.clone(),
);
let _ = inode_bitmap.allocate().unwrap(); // inode block 0 is not usable
let mut fs = Self {
device: device.clone(),
data_bitmap,
inode_bitmap,
inode_start_block: data_bitmap_block_number + inode_bitmap_block_number + 1,
data_start_block: data_bitmap_block_number
+ inode_bitmap_block_number
+ inode_block_number
+ 1,
cached_inodes: BlockCache::new(device.clone(), 1024),
cached_blocks: BlockCache::new(device.clone(), 8192),
};
fs.create_directory(0o755, get_current_uid(), get_current_gid(), 0, None);
fs
}
}
fn main() {
env_logger::init();
let args = Args::parse();
let mount_point = args.mount_point.unwrap();
let options = vec![
// MountOption::RO,
MountOption::FSName("hello".to_string()),
MountOption::AutoUnmount,
MountOption::AllowRoot,
];
let mem_disk = Arc::new(MemoryDisk::new(16384));
let filesystem = AyaFS::new(mem_disk, 16384);
fuser::mount2(filesystem, mount_point, &options).unwrap();
}
|
