forked from M-Labs/rust-fatfs
Mark volume dirty on first write and not-dirty on unmount
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1
TODO.md
1
TODO.md
@ -1,6 +1,5 @@
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TODO
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====
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* marking volume dirty on first write and not-dirty on unmount
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* support for a volume label file in the root directory
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* format volume API
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* add method for getting `DirEntry` from a path (possible names: metadata, lookup)
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@ -229,6 +229,8 @@ impl<'a, T: ReadWriteSeek> Write for File<'a, T> {
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if write_size == 0 {
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return Ok(0);
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}
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// Mark the volume 'dirty'
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self.fs.set_dirty_flag(true)?;
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// Get cluster for write possibly allocating new one
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let current_cluster = if self.offset % cluster_size == 0 {
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// next cluster
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58
src/fs.rs
58
src/fs.rs
@ -1,6 +1,6 @@
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#[cfg(all(not(feature = "std"), feature = "alloc"))]
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use alloc::String;
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use core::cell::RefCell;
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use core::cell::{Cell, RefCell};
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use core::char;
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use core::cmp;
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use core::fmt::Debug;
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@ -66,6 +66,24 @@ impl FsStatusFlags {
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pub fn io_error(&self) -> bool {
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self.io_error
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}
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fn encode(&self) -> u8 {
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let mut res = 0u8;
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if self.dirty {
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res |= 1;
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}
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if self.io_error {
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res |= 2;
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}
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res
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}
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fn decode(flags: u8) -> Self {
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FsStatusFlags {
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dirty: flags & 1 != 0,
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io_error: flags & 2 != 0,
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}
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}
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}
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/// A sum of `Read` and `Seek` traits.
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@ -178,10 +196,7 @@ impl BiosParameterBlock {
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}
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fn status_flags(&self) -> FsStatusFlags {
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FsStatusFlags {
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dirty: self.reserved_1 & 1 != 0,
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io_error: self.reserved_1 & 2 != 0,
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}
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FsStatusFlags::decode(self.reserved_1)
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}
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}
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@ -374,6 +389,7 @@ pub struct FileSystem<T: ReadWriteSeek> {
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root_dir_sectors: u32,
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total_clusters: u32,
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fs_info: RefCell<FsInfoSector>,
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current_status_flags: Cell<FsStatusFlags>,
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}
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impl<T: ReadWriteSeek> FileSystem<T> {
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@ -434,6 +450,7 @@ impl<T: ReadWriteSeek> FileSystem<T> {
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}
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// return FileSystem struct
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let status_flags = bpb.status_flags();
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Ok(FileSystem {
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disk: RefCell::new(disk),
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options,
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@ -443,6 +460,7 @@ impl<T: ReadWriteSeek> FileSystem<T> {
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root_dir_sectors,
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total_clusters,
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fs_info: RefCell::new(fs_info),
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current_status_flags: Cell::new(status_flags),
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})
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}
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@ -605,6 +623,7 @@ impl<T: ReadWriteSeek> FileSystem<T> {
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fn unmount_internal(&self) -> io::Result<()> {
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self.flush_fs_info()?;
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self.set_dirty_flag(false)?;
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Ok(())
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}
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@ -618,6 +637,27 @@ impl<T: ReadWriteSeek> FileSystem<T> {
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}
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Ok(())
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}
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pub(crate) fn set_dirty_flag(&self, dirty: bool) -> io::Result<()> {
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// Do not overwrite flags read from BPB on mount
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let mut flags = self.bpb.status_flags();
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flags.dirty |= dirty;
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// Check if flags has changed
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let current_flags = self.current_status_flags.get();
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if flags == current_flags {
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// Nothing to do
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return Ok(());
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}
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let encoded = flags.encode();
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// Note: only one field is written to avoid rewriting entire boot-sector which could be dangerous
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// Compute reserver_1 field offset and write new flags
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let offset = if self.fat_type() == FatType::Fat32 { 0x041 } else { 0x025 };
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let mut disk = self.disk.borrow_mut();
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disk.seek(io::SeekFrom::Start(offset))?;
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disk.write_u8(encoded)?;
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self.current_status_flags.set(flags);
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Ok(())
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}
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}
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/// `Drop` implementation tries to unmount the filesystem when dropping.
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@ -692,8 +732,14 @@ impl<'a, T: ReadWriteSeek> Write for DiskSlice<'a, T> {
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fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
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let offset = self.begin + self.offset;
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let write_size = cmp::min((self.size - self.offset) as usize, buf.len());
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for i in 0..self.mirrors {
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if write_size == 0 {
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return Ok(0);
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}
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// Mark the volume 'dirty'
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self.fs.set_dirty_flag(true)?;
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// Write data
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let mut disk = self.fs.disk.borrow_mut();
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for i in 0..self.mirrors {
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disk.seek(SeekFrom::Start(offset + i as u64 * self.size))?;
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disk.write_all(&buf[..write_size])?;
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}
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@ -5,6 +5,7 @@ extern crate fscommon;
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use std::fs;
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use std::io;
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use std::io::prelude::*;
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use std::mem;
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use std::str;
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use fatfs::FsOptions;
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@ -20,20 +21,28 @@ const TEST_STR2: &str = "Rust is cool!\n";
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type FileSystem = fatfs::FileSystem<BufStream<fs::File>>;
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fn call_with_fs(f: &Fn(FileSystem) -> (), filename: &str, test_seq: u32) {
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fn call_with_tmp_img(f: &Fn(&str) -> (), filename: &str, test_seq: u32) {
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let _ = env_logger::try_init();
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let img_path = format!("{}/{}", IMG_DIR, filename);
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let tmp_path = format!("{}/{}-{}", TMP_DIR, test_seq, filename);
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fs::create_dir(TMP_DIR).ok();
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fs::copy(&img_path, &tmp_path).unwrap();
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{
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f(tmp_path.as_str());
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fs::remove_file(tmp_path).unwrap();
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}
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fn open_filesystem_rw(tmp_path: &str) -> FileSystem {
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let file = fs::OpenOptions::new().read(true).write(true).open(&tmp_path).unwrap();
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let buf_file = BufStream::new(file);
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let options = FsOptions::new().update_accessed_date(true);
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let fs = FileSystem::new(buf_file, options).unwrap();
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f(fs);
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FileSystem::new(buf_file, options).unwrap()
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}
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fs::remove_file(tmp_path).unwrap();
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fn call_with_fs(f: &Fn(FileSystem) -> (), filename: &str, test_seq: u32) {
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call_with_tmp_img(&|tmp_path| {
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let fs = open_filesystem_rw(tmp_path);
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f(fs);
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}, filename, test_seq);
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}
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fn test_write_short_file(fs: FileSystem) {
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@ -296,3 +305,27 @@ fn test_rename_file_fat16() {
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fn test_rename_file_fat32() {
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call_with_fs(&test_rename_file, FAT32_IMG, 6)
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}
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#[test]
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fn test_dirty_flag() {
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call_with_tmp_img(&|tmp_path| {
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// Open filesystem, make change, and forget it - should become dirty
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let fs = open_filesystem_rw(tmp_path);
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let status_flags = fs.read_status_flags().unwrap();
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assert_eq!(status_flags.dirty(), false);
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assert_eq!(status_flags.io_error(), false);
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fs.root_dir().create_file("abc.txt").unwrap();
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mem::forget(fs);
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// Check if volume is dirty now
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let fs = open_filesystem_rw(tmp_path);
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let status_flags = fs.read_status_flags().unwrap();
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assert_eq!(status_flags.dirty(), true);
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assert_eq!(status_flags.io_error(), false);
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fs.unmount().unwrap();
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// Make sure remounting does not clear the dirty flag
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let fs = open_filesystem_rw(tmp_path);
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let status_flags = fs.read_status_flags().unwrap();
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assert_eq!(status_flags.dirty(), true);
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assert_eq!(status_flags.io_error(), false);
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}, FAT32_IMG, 7);
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}
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