1 use alloc::string::ToString; 2 use core::cmp::Ordering; 3 use core::intrinsics::unlikely; 4 use core::{any::Any, fmt::Debug}; 5 use hashbrown::HashMap; 6 use log::error; 7 use system_error::SystemError; 8 9 use alloc::{ 10 string::String, 11 sync::{Arc, Weak}, 12 vec::Vec, 13 }; 14 15 use crate::driver::base::block::gendisk::GenDisk; 16 use crate::driver::base::device::device_number::DeviceNumber; 17 use crate::filesystem::vfs::file::PageCache; 18 use crate::filesystem::vfs::utils::DName; 19 use crate::filesystem::vfs::{Magic, SpecialNodeData, SuperBlock}; 20 use crate::ipc::pipe::LockedPipeInode; 21 use crate::mm::fault::{PageFaultHandler, PageFaultMessage}; 22 use crate::mm::VmFaultReason; 23 use crate::{ 24 driver::base::block::{block_device::LBA_SIZE, disk_info::Partition, SeekFrom}, 25 filesystem::vfs::{ 26 core::generate_inode_id, 27 file::{FileMode, FilePrivateData}, 28 syscall::ModeType, 29 FileSystem, FileType, IndexNode, InodeId, Metadata, 30 }, 31 libs::{ 32 spinlock::{SpinLock, SpinLockGuard}, 33 vec_cursor::VecCursor, 34 }, 35 time::PosixTimeSpec, 36 }; 37 38 use super::entry::FATFile; 39 use super::utils::{to_search_name, to_search_name_string}; 40 use super::{ 41 bpb::{BiosParameterBlock, FATType}, 42 entry::{FATDir, FATDirEntry, FATDirIter, FATEntry}, 43 utils::RESERVED_CLUSTERS, 44 }; 45 46 const FAT_MAX_NAMELEN: u64 = 255; 47 48 /// FAT32文件系统的最大的文件大小 49 pub const MAX_FILE_SIZE: u64 = 0xffff_ffff; 50 51 /// @brief 表示当前簇和上一个簇的关系的结构体 52 /// 定义这样一个结构体的原因是，FAT文件系统的文件中，前后两个簇具有关联关系。 53 #[allow(dead_code)] 54 #[derive(Debug, Clone, Copy, Default)] 55 pub struct Cluster { 56 pub cluster_num: u64, 57 pub parent_cluster: u64, 58 } 59 60 impl PartialOrd for Cluster { 61 /// @brief 根据当前簇号比较大小 partial_cmp(&self, other: &Self) -> Option<core::cmp::Ordering>62 fn partial_cmp(&self, other: &Self) -> Option<core::cmp::Ordering> { 63 return self.cluster_num.partial_cmp(&other.cluster_num); 64 } 65 } 66 67 impl PartialEq for Cluster { 68 /// @brief 根据当前簇号比较是否相等 eq(&self, other: &Self) -> bool69 fn eq(&self, other: &Self) -> bool { 70 self.cluster_num == other.cluster_num 71 } 72 } 73 74 impl Eq for Cluster {} 75 76 #[derive(Debug)] 77 pub struct FATFileSystem { 78 /// 当前文件系统所在的分区 79 pub gendisk: Arc<GenDisk>, 80 /// 当前文件系统的BOPB 81 pub bpb: BiosParameterBlock, 82 /// 当前文件系统的第一个数据扇区（相对分区开始位置） 83 pub first_data_sector: u64, 84 /// 文件系统信息结构体 85 pub fs_info: Arc<LockedFATFsInfo>, 86 /// 文件系统的根inode 87 root_inode: Arc<LockedFATInode>, 88 } 89 90 /// FAT文件系统的Inode 91 #[derive(Debug)] 92 pub struct LockedFATInode(SpinLock<FATInode>); 93 94 #[derive(Debug)] 95 pub struct LockedFATFsInfo(SpinLock<FATFsInfo>); 96 97 impl LockedFATFsInfo { 98 #[inline] new(fs_info: FATFsInfo) -> Self99 pub fn new(fs_info: FATFsInfo) -> Self { 100 return Self(SpinLock::new(fs_info)); 101 } 102 } 103 104 #[derive(Debug)] 105 pub struct FATInode { 106 /// 指向父Inode的弱引用 107 parent: Weak<LockedFATInode>, 108 /// 指向自身的弱引用 109 self_ref: Weak<LockedFATInode>, 110 /// 子Inode的map. 该数据结构用作缓存区。其中，它的key表示inode的名称。 111 /// 请注意，由于FAT的查询过程对大小写不敏感，因此我们选择让key全部是大写的，方便统一操作。 112 children: HashMap<String, Arc<LockedFATInode>>, 113 /// 当前inode的元数据 114 metadata: Metadata, 115 /// 指向inode所在的文件系统对象的指针 116 fs: Weak<FATFileSystem>, 117 118 /// 根据不同的Inode类型，创建不同的私有字段 119 inode_type: FATDirEntry, 120 121 /// 若该节点是特殊文件节点，该字段则为真正的文件节点 122 special_node: Option<SpecialNodeData>, 123 124 /// 目录名 125 dname: DName, 126 127 /// 页缓存 128 page_cache: Option<Arc<PageCache>>, 129 } 130 131 impl FATInode { 132 /// @brief 更新当前inode的元数据 update_metadata(&mut self)133 pub fn update_metadata(&mut self) { 134 // todo: 更新文件的访问时间等信息 135 match &self.inode_type { 136 FATDirEntry::File(f) | FATDirEntry::VolId(f) => { 137 self.metadata.size = f.size() as i64; 138 } 139 FATDirEntry::Dir(d) => { 140 self.metadata.size = d.size(&self.fs.upgrade().unwrap().clone()) as i64; 141 } 142 FATDirEntry::UnInit => { 143 error!("update_metadata: Uninitialized FATDirEntry: {:?}", self); 144 return; 145 } 146 }; 147 } 148 find(&mut self, name: &str) -> Result<Arc<LockedFATInode>, SystemError>149 fn find(&mut self, name: &str) -> Result<Arc<LockedFATInode>, SystemError> { 150 match &self.inode_type { 151 FATDirEntry::Dir(d) => { 152 let search_name = to_search_name(name); 153 // 尝试在缓存区查找 154 if let Some(entry) = self.children.get(&search_name) { 155 return Ok(entry.clone()); 156 } 157 // 在缓存区找不到 158 // 在磁盘查找 159 let fat_entry: FATDirEntry = 160 d.find_entry(name, None, None, self.fs.upgrade().unwrap())?; 161 let dname = DName::from(name); 162 // 创建新的inode 163 let entry_inode: Arc<LockedFATInode> = LockedFATInode::new( 164 dname, 165 self.fs.upgrade().unwrap(), 166 self.self_ref.clone(), 167 fat_entry, 168 ); 169 // 加入缓存区, 由于FAT文件系统的大小写不敏感问题，因此存入缓存区的key应当是全大写的 170 self.children.insert(search_name, entry_inode.clone()); 171 return Ok(entry_inode); 172 } 173 FATDirEntry::UnInit => { 174 panic!( 175 "Uninitialized FAT Inode, fs = {:?}, inode={self:?}", 176 self.fs 177 ) 178 } 179 _ => { 180 return Err(SystemError::ENOTDIR); 181 } 182 } 183 } 184 } 185 186 impl LockedFATInode { new( dname: DName, fs: Arc<FATFileSystem>, parent: Weak<LockedFATInode>, inode_type: FATDirEntry, ) -> Arc<LockedFATInode>187 pub fn new( 188 dname: DName, 189 fs: Arc<FATFileSystem>, 190 parent: Weak<LockedFATInode>, 191 inode_type: FATDirEntry, 192 ) -> Arc<LockedFATInode> { 193 let file_type = if let FATDirEntry::Dir(_) = inode_type { 194 FileType::Dir 195 } else { 196 FileType::File 197 }; 198 199 let inode: Arc<LockedFATInode> = Arc::new(LockedFATInode(SpinLock::new(FATInode { 200 parent, 201 self_ref: Weak::default(), 202 children: HashMap::new(), 203 fs: Arc::downgrade(&fs), 204 inode_type, 205 metadata: Metadata { 206 dev_id: 0, 207 inode_id: generate_inode_id(), 208 size: 0, 209 blk_size: fs.bpb.bytes_per_sector as usize, 210 blocks: if let FATType::FAT32(_) = fs.bpb.fat_type { 211 fs.bpb.total_sectors_32 as usize 212 } else { 213 fs.bpb.total_sectors_16 as usize 214 }, 215 atime: PosixTimeSpec::default(), 216 mtime: PosixTimeSpec::default(), 217 ctime: PosixTimeSpec::default(), 218 file_type, 219 mode: ModeType::from_bits_truncate(0o777), 220 nlinks: 1, 221 uid: 0, 222 gid: 0, 223 raw_dev: DeviceNumber::default(), 224 }, 225 special_node: None, 226 dname, 227 page_cache: None, 228 }))); 229 230 if !inode.0.lock().inode_type.is_dir() { 231 let page_cache = PageCache::new(Some(Arc::downgrade(&inode) as Weak<dyn IndexNode>)); 232 inode.0.lock().page_cache = Some(page_cache); 233 } 234 235 inode.0.lock().self_ref = Arc::downgrade(&inode); 236 237 inode.0.lock().update_metadata(); 238 239 return inode; 240 } 241 } 242 243 /// FsInfo结构体（内存中的一份拷贝，当卸载卷或者sync的时候，把它写入磁盘） 244 #[derive(Debug)] 245 pub struct FATFsInfo { 246 /// Lead Signature - must equal 0x41615252 247 lead_sig: u32, 248 /// Value must equal 0x61417272 249 struc_sig: u32, 250 /// 空闲簇数目 251 free_count: u32, 252 /// 第一个空闲簇的位置（不一定准确，仅供加速查找） 253 next_free: u32, 254 /// 0xAA550000 255 trail_sig: u32, 256 /// Dirty flag to flush to disk 257 dirty: bool, 258 /// FsInfo Structure 在磁盘上的字节偏移量 259 /// Not present for FAT12 and FAT16 260 offset: Option<u64>, 261 } 262 263 impl FileSystem for FATFileSystem { root_inode(&self) -> Arc<dyn crate::filesystem::vfs::IndexNode>264 fn root_inode(&self) -> Arc<dyn crate::filesystem::vfs::IndexNode> { 265 return self.root_inode.clone(); 266 } 267 info(&self) -> crate::filesystem::vfs::FsInfo268 fn info(&self) -> crate::filesystem::vfs::FsInfo { 269 todo!() 270 } 271 272 /// @brief 本函数用于实现动态转换。 273 /// 具体的文件系统在实现本函数时，最简单的方式就是：直接返回self as_any_ref(&self) -> &dyn Any274 fn as_any_ref(&self) -> &dyn Any { 275 self 276 } 277 name(&self) -> &str278 fn name(&self) -> &str { 279 "fat" 280 } 281 super_block(&self) -> SuperBlock282 fn super_block(&self) -> SuperBlock { 283 SuperBlock::new( 284 Magic::FAT_MAGIC, 285 self.bpb.bytes_per_sector.into(), 286 FAT_MAX_NAMELEN, 287 ) 288 } 289 fault(&self, pfm: &mut PageFaultMessage) -> VmFaultReason290 unsafe fn fault(&self, pfm: &mut PageFaultMessage) -> VmFaultReason { 291 PageFaultHandler::filemap_fault(pfm) 292 } 293 map_pages( &self, pfm: &mut PageFaultMessage, start_pgoff: usize, end_pgoff: usize, ) -> VmFaultReason294 unsafe fn map_pages( 295 &self, 296 pfm: &mut PageFaultMessage, 297 start_pgoff: usize, 298 end_pgoff: usize, 299 ) -> VmFaultReason { 300 PageFaultHandler::filemap_map_pages(pfm, start_pgoff, end_pgoff) 301 } 302 } 303 304 impl FATFileSystem { 305 /// FAT12允许的最大簇号 306 pub const FAT12_MAX_CLUSTER: u32 = 0xFF5; 307 /// FAT16允许的最大簇号 308 pub const FAT16_MAX_CLUSTER: u32 = 0xFFF5; 309 /// FAT32允许的最大簇号 310 pub const FAT32_MAX_CLUSTER: u32 = 0x0FFFFFF7; 311 new(gendisk: Arc<GenDisk>) -> Result<Arc<FATFileSystem>, SystemError>312 pub fn new(gendisk: Arc<GenDisk>) -> Result<Arc<FATFileSystem>, SystemError> { 313 let bpb = BiosParameterBlock::new(&gendisk)?; 314 // 从磁盘上读取FAT32文件系统的FsInfo结构体 315 let fs_info: FATFsInfo = match bpb.fat_type { 316 FATType::FAT32(bpb32) => { 317 let fs_info_in_gendisk_bytes_offset = 318 bpb32.fs_info as usize * bpb.bytes_per_sector as usize; 319 FATFsInfo::new( 320 &gendisk, 321 fs_info_in_gendisk_bytes_offset, 322 bpb.bytes_per_sector as usize, 323 )? 324 } 325 _ => FATFsInfo::default(), 326 }; 327 328 // 根目录项占用的扇区数（向上取整） 329 let root_dir_sectors: u64 = 330 (bpb.root_entries_cnt as u64 * 32).div_ceil(bpb.bytes_per_sector as u64); 331 332 // FAT表大小（单位：扇区） 333 let fat_size = if bpb.fat_size_16 != 0 { 334 bpb.fat_size_16 as u64 335 } else { 336 match bpb.fat_type { 337 FATType::FAT32(x) => x.fat_size_32 as u64, 338 _ => { 339 error!("FAT12 and FAT16 volumes should have non-zero BPB_FATSz16"); 340 return Err(SystemError::EINVAL); 341 } 342 } 343 }; 344 345 let first_data_sector = 346 bpb.rsvd_sec_cnt as u64 + (bpb.num_fats as u64 * fat_size) + root_dir_sectors; 347 348 // 创建文件系统的根节点 349 let root_inode: Arc<LockedFATInode> = Arc::new(LockedFATInode(SpinLock::new(FATInode { 350 parent: Weak::default(), 351 self_ref: Weak::default(), 352 children: HashMap::new(), 353 fs: Weak::default(), 354 inode_type: FATDirEntry::UnInit, 355 metadata: Metadata { 356 dev_id: 0, 357 inode_id: generate_inode_id(), 358 size: 0, 359 blk_size: bpb.bytes_per_sector as usize, 360 blocks: if let FATType::FAT32(_) = bpb.fat_type { 361 bpb.total_sectors_32 as usize 362 } else { 363 bpb.total_sectors_16 as usize 364 }, 365 atime: PosixTimeSpec::default(), 366 mtime: PosixTimeSpec::default(), 367 ctime: PosixTimeSpec::default(), 368 file_type: FileType::Dir, 369 mode: ModeType::from_bits_truncate(0o777), 370 nlinks: 1, 371 uid: 0, 372 gid: 0, 373 raw_dev: DeviceNumber::default(), 374 }, 375 special_node: None, 376 dname: DName::default(), 377 page_cache: None, 378 }))); 379 380 let result: Arc<FATFileSystem> = Arc::new(FATFileSystem { 381 gendisk, 382 bpb, 383 first_data_sector, 384 fs_info: Arc::new(LockedFATFsInfo::new(fs_info)), 385 root_inode, 386 }); 387 388 // 对root inode加锁，并继续完成初始化工作 389 let mut root_guard: SpinLockGuard<FATInode> = result.root_inode.0.lock(); 390 root_guard.inode_type = FATDirEntry::Dir(result.root_dir()); 391 root_guard.parent = Arc::downgrade(&result.root_inode); 392 root_guard.self_ref = Arc::downgrade(&result.root_inode); 393 root_guard.fs = Arc::downgrade(&result); 394 // 释放锁 395 drop(root_guard); 396 397 return Ok(result); 398 } 399 400 /// @brief 计算每个簇有多少个字节 401 #[inline] bytes_per_cluster(&self) -> u64402 pub fn bytes_per_cluster(&self) -> u64 { 403 return (self.bpb.bytes_per_sector as u64) * (self.bpb.sector_per_cluster as u64); 404 } 405 406 /// @brief 读取当前簇在FAT表中存储的信息 407 /// 408 /// @param cluster 当前簇 409 /// 410 /// @return Ok(FATEntry) 当前簇在FAT表中，存储的信息。（详情见FATEntry的注释） 411 /// @return Err(SystemError) 错误码 get_fat_entry(&self, cluster: Cluster) -> Result<FATEntry, SystemError>412 pub fn get_fat_entry(&self, cluster: Cluster) -> Result<FATEntry, SystemError> { 413 let current_cluster = cluster.cluster_num; 414 if current_cluster < 2 { 415 // 0号簇和1号簇是保留簇，不允许用户使用 416 return Err(SystemError::EINVAL); 417 } 418 419 let fat_type: FATType = self.bpb.fat_type; 420 // 获取FAT表的起始扇区（相对分区起始扇区的偏移量） 421 let fat_start_sector = self.fat_start_sector(); 422 let bytes_per_sec = self.bpb.bytes_per_sector as u64; 423 424 // cluster对应的FAT表项在分区内的字节偏移量 425 let fat_bytes_offset = 426 fat_type.get_fat_bytes_offset(cluster, fat_start_sector, bytes_per_sec); 427 428 // FAT表项所在的分区内LBA地址 429 let fat_ent_lba = fat_bytes_offset / LBA_SIZE as u64; 430 431 // FAT表项在逻辑块内的字节偏移量 432 let blk_offset = self.get_in_block_offset(fat_bytes_offset); 433 434 let mut v: Vec<u8> = vec![0; self.bpb.bytes_per_sector as usize]; 435 self.gendisk.read_at(&mut v, fat_ent_lba as usize)?; 436 437 let mut cursor = VecCursor::new(v); 438 cursor.seek(SeekFrom::SeekSet(blk_offset as i64))?; 439 440 let res: FATEntry = match self.bpb.fat_type { 441 FATType::FAT12(_) => { 442 let mut entry = cursor.read_u16()?; 443 // 由于FAT12文件系统的FAT表，每个entry占用1.5字节，因此奇数的簇需要取高12位的值。 444 if (current_cluster & 1) > 0 { 445 entry >>= 4; 446 } else { 447 entry &= 0x0fff; 448 } 449 450 if entry == 0 { 451 FATEntry::Unused 452 } else if entry == 0x0ff7 { 453 FATEntry::Bad 454 } else if entry >= 0x0ff8 { 455 FATEntry::EndOfChain 456 } else { 457 FATEntry::Next(Cluster { 458 cluster_num: entry as u64, 459 parent_cluster: current_cluster, 460 }) 461 } 462 } 463 FATType::FAT16(_) => { 464 let entry = cursor.read_u16()?; 465 466 if entry == 0 { 467 FATEntry::Unused 468 } else if entry == 0xfff7 { 469 FATEntry::Bad 470 } else if entry >= 0xfff8 { 471 FATEntry::EndOfChain 472 } else { 473 FATEntry::Next(Cluster { 474 cluster_num: entry as u64, 475 parent_cluster: current_cluster, 476 }) 477 } 478 } 479 FATType::FAT32(_) => { 480 let entry = cursor.read_u32()? & 0x0fffffff; 481 482 match entry { 483 _n if (0x0ffffff7..=0x0fffffff).contains(¤t_cluster) => { 484 // 当前簇号不是一个能被获得的簇（可能是文件系统出错了） 485 error!("FAT32 get fat entry: current cluster number [{}] is not an allocatable cluster number.", current_cluster); 486 FATEntry::Bad 487 } 488 0 => FATEntry::Unused, 489 0x0ffffff7 => FATEntry::Bad, 490 0x0ffffff8..=0x0fffffff => FATEntry::EndOfChain, 491 _n => FATEntry::Next(Cluster { 492 cluster_num: entry as u64, 493 parent_cluster: current_cluster, 494 }), 495 } 496 } 497 }; 498 return Ok(res); 499 } 500 501 /// @brief 读取当前簇在FAT表中存储的信息（直接返回读取到的值，而不加处理） 502 /// 503 /// @param cluster 当前簇 504 /// 505 /// @return Ok(u64) 当前簇在FAT表中，存储的信息。 506 /// @return Err(SystemError) 错误码 get_fat_entry_raw(&self, cluster: Cluster) -> Result<u64, SystemError>507 pub fn get_fat_entry_raw(&self, cluster: Cluster) -> Result<u64, SystemError> { 508 let current_cluster = cluster.cluster_num; 509 510 let fat_type: FATType = self.bpb.fat_type; 511 // 获取FAT表的起始扇区（相对分区起始扇区的偏移量） 512 let fat_start_sector = self.fat_start_sector(); 513 let bytes_per_sec = self.bpb.bytes_per_sector as u64; 514 515 // cluster对应的FAT表项在分区内的字节偏移量 516 let fat_bytes_offset = 517 fat_type.get_fat_bytes_offset(cluster, fat_start_sector, bytes_per_sec); 518 519 // FAT表项所在的分区内LBA地址 520 let fat_ent_lba = self.gendisk_lba_from_offset(self.bytes_to_sector(fat_bytes_offset)); 521 522 // FAT表项在逻辑块内的字节偏移量 523 let blk_offset = self.get_in_block_offset(fat_bytes_offset); 524 525 let mut v: Vec<u8> = vec![0; self.bpb.bytes_per_sector as usize]; 526 self.gendisk.read_at(&mut v, fat_ent_lba)?; 527 528 let mut cursor = VecCursor::new(v); 529 cursor.seek(SeekFrom::SeekSet(blk_offset as i64))?; 530 531 let res = match self.bpb.fat_type { 532 FATType::FAT12(_) => { 533 let mut entry = cursor.read_u16()?; 534 entry = if (current_cluster & 0x0001) > 0 { 535 entry >> 4 536 } else { 537 entry & 0x0fff 538 }; 539 entry as u64 540 } 541 FATType::FAT16(_) => { 542 let entry = (cursor.read_u16()?) as u64; 543 entry 544 } 545 FATType::FAT32(_) => { 546 let entry = cursor.read_u32()? & 0x0fff_ffff; 547 entry as u64 548 } 549 }; 550 551 return Ok(res); 552 } 553 554 /// @brief 获取当前文件系统的root inode，在分区内的字节偏移量 root_dir_bytes_offset(&self) -> u64555 pub fn root_dir_bytes_offset(&self) -> u64 { 556 match self.bpb.fat_type { 557 FATType::FAT32(s) => { 558 let first_sec_cluster: u64 = (s.root_cluster as u64 - 2) 559 * (self.bpb.sector_per_cluster as u64) 560 + self.first_data_sector; 561 return (self.gendisk_lba_from_offset(first_sec_cluster) * LBA_SIZE) as u64; 562 } 563 _ => { 564 let root_sec = (self.bpb.rsvd_sec_cnt as u64) 565 + (self.bpb.num_fats as u64) * (self.bpb.fat_size_16 as u64); 566 return (self.gendisk_lba_from_offset(root_sec) * LBA_SIZE) as u64; 567 } 568 } 569 } 570 571 /// @brief 获取当前文件系统的根目录项区域的结束位置，在分区内的字节偏移量。 572 /// 请注意，当前函数只对FAT12/FAT16生效。对于FAT32,返回None root_dir_end_bytes_offset(&self) -> Option<u64>573 pub fn root_dir_end_bytes_offset(&self) -> Option<u64> { 574 match self.bpb.fat_type { 575 FATType::FAT12(_) | FATType::FAT16(_) => { 576 return Some( 577 self.root_dir_bytes_offset() + (self.bpb.root_entries_cnt as u64) * 32, 578 ); 579 } 580 _ => { 581 return None; 582 } 583 } 584 } 585 586 /// 获取簇在分区内的字节偏移量 cluster_bytes_offset(&self, cluster: Cluster) -> u64587 pub fn cluster_bytes_offset(&self, cluster: Cluster) -> u64 { 588 if cluster.cluster_num >= 2 { 589 // 指定簇的第一个扇区号 590 let first_sec_of_cluster = (cluster.cluster_num - 2) 591 * (self.bpb.sector_per_cluster as u64) 592 + self.first_data_sector; 593 return first_sec_of_cluster * (self.bpb.bytes_per_sector as u64); 594 } else { 595 return 0; 596 } 597 } 598 599 /// @brief 获取一个空闲簇 600 /// 601 /// @param prev_cluster 簇链的前一个簇。本函数将会把新获取的簇，连接到它的后面。 602 /// 603 /// @return Ok(Cluster) 新获取的空闲簇 604 /// @return Err(SystemError) 错误码 allocate_cluster(&self, prev_cluster: Option<Cluster>) -> Result<Cluster, SystemError>605 pub fn allocate_cluster(&self, prev_cluster: Option<Cluster>) -> Result<Cluster, SystemError> { 606 let end_cluster: Cluster = self.max_cluster_number(); 607 let start_cluster: Cluster = match self.bpb.fat_type { 608 FATType::FAT32(_) => { 609 let next_free: u64 = self.fs_info.0.lock().next_free().unwrap_or(0xffffffff); 610 if next_free < end_cluster.cluster_num { 611 Cluster::new(next_free) 612 } else { 613 Cluster::new(RESERVED_CLUSTERS as u64) 614 } 615 } 616 _ => Cluster::new(RESERVED_CLUSTERS as u64), 617 }; 618 619 // 寻找一个空的簇 620 let free_cluster: Cluster = match self.get_free_cluster(start_cluster, end_cluster) { 621 Ok(c) => c, 622 Err(_) if start_cluster.cluster_num > RESERVED_CLUSTERS as u64 => { 623 self.get_free_cluster(Cluster::new(RESERVED_CLUSTERS as u64), end_cluster)? 624 } 625 Err(e) => return Err(e), 626 }; 627 628 self.set_entry(free_cluster, FATEntry::EndOfChain)?; 629 // 减少空闲簇计数 630 self.fs_info.0.lock().update_free_count_delta(-1); 631 // 更新搜索空闲簇的参考量 632 self.fs_info 633 .0 634 .lock() 635 .update_next_free((free_cluster.cluster_num + 1) as u32); 636 637 // 如果这个空闲簇不是簇链的第一个簇，那么把当前簇跟前一个簇连上。 638 if let Some(prev_cluster) = prev_cluster { 639 // debug!("set entry, prev ={prev_cluster:?}, next = {free_cluster:?}"); 640 self.set_entry(prev_cluster, FATEntry::Next(free_cluster))?; 641 } 642 // 清空新获取的这个簇 643 self.zero_cluster(free_cluster)?; 644 return Ok(free_cluster); 645 } 646 647 /// @brief 释放簇链上的所有簇 648 /// 649 /// @param start_cluster 簇链的第一个簇 deallocate_cluster_chain(&self, start_cluster: Cluster) -> Result<(), SystemError>650 pub fn deallocate_cluster_chain(&self, start_cluster: Cluster) -> Result<(), SystemError> { 651 let clusters: Vec<Cluster> = self.clusters(start_cluster); 652 for c in clusters { 653 self.deallocate_cluster(c)?; 654 } 655 return Ok(()); 656 } 657 658 /// @brief 释放簇 659 /// 660 /// @param 要释放的簇 deallocate_cluster(&self, cluster: Cluster) -> Result<(), SystemError>661 pub fn deallocate_cluster(&self, cluster: Cluster) -> Result<(), SystemError> { 662 let entry: FATEntry = self.get_fat_entry(cluster)?; 663 // 如果不是坏簇 664 if entry != FATEntry::Bad { 665 self.set_entry(cluster, FATEntry::Unused)?; 666 self.fs_info.0.lock().update_free_count_delta(1); 667 // 安全选项：清空被释放的簇 668 #[cfg(feature = "fatfs-secure")] 669 self.zero_cluster(cluster)?; 670 return Ok(()); 671 } else { 672 // 不能释放坏簇 673 error!("Bad clusters cannot be freed."); 674 return Err(SystemError::EFAULT); 675 } 676 } 677 678 /// @brief 获取文件系统的根目录项 root_dir(&self) -> FATDir679 pub fn root_dir(&self) -> FATDir { 680 match self.bpb.fat_type { 681 FATType::FAT32(s) => { 682 return FATDir { 683 first_cluster: Cluster::new(s.root_cluster as u64), 684 dir_name: String::from("/"), 685 root_offset: None, 686 short_dir_entry: None, 687 loc: None, 688 }; 689 } 690 _ => FATDir { 691 first_cluster: Cluster::new(0), 692 dir_name: String::from("/"), 693 root_offset: Some(self.root_dir_bytes_offset()), 694 short_dir_entry: None, 695 loc: None, 696 }, 697 } 698 } 699 700 /// @brief 获取FAT表的起始扇区（相对分区起始扇区的偏移量） fat_start_sector(&self) -> u64701 pub fn fat_start_sector(&self) -> u64 { 702 let active_fat = self.active_fat(); 703 let fat_size = self.fat_size(); 704 return self.bpb.rsvd_sec_cnt as u64 + active_fat * fat_size; 705 } 706 707 /// @brief 获取当前活动的FAT表 active_fat(&self) -> u64708 pub fn active_fat(&self) -> u64 { 709 if self.mirroring_enabled() { 710 return 0; 711 } else { 712 match self.bpb.fat_type { 713 FATType::FAT32(bpb32) => { 714 return (bpb32.ext_flags & 0x0f) as u64; 715 } 716 _ => { 717 return 0; 718 } 719 } 720 } 721 } 722 723 /// @brief 获取当前文件系统的每个FAT表的大小 fat_size(&self) -> u64724 pub fn fat_size(&self) -> u64 { 725 if self.bpb.fat_size_16 != 0 { 726 return self.bpb.fat_size_16 as u64; 727 } else { 728 match self.bpb.fat_type { 729 FATType::FAT32(bpb32) => { 730 return bpb32.fat_size_32 as u64; 731 } 732 733 _ => { 734 panic!("FAT12 and FAT16 volumes should have non-zero BPB_FATSz16"); 735 } 736 } 737 } 738 } 739 740 /// @brief 判断当前文件系统是否启用了FAT表镜像 mirroring_enabled(&self) -> bool741 pub fn mirroring_enabled(&self) -> bool { 742 match self.bpb.fat_type { 743 FATType::FAT32(bpb32) => { 744 return (bpb32.ext_flags & 0x80) == 0; 745 } 746 _ => { 747 return false; 748 } 749 } 750 } 751 752 /// 获取分区内的扇区偏移量 753 #[inline] gendisk_lba_from_offset(&self, in_partition_sec_offset: u64) -> usize754 pub fn gendisk_lba_from_offset(&self, in_partition_sec_offset: u64) -> usize { 755 return (in_partition_sec_offset * (self.bpb.bytes_per_sector as u64 / LBA_SIZE as u64)) 756 as usize; 757 } 758 759 /// @brief 获取每个扇区占用多少个LBA 760 #[inline] lba_per_sector(&self) -> usize761 pub fn lba_per_sector(&self) -> usize { 762 return self.bpb.bytes_per_sector as usize / LBA_SIZE; 763 } 764 765 /// @brief 将分区内字节偏移量转换为扇区偏移量 766 #[inline] bytes_to_sector(&self, in_partition_bytes_offset: u64) -> u64767 pub fn bytes_to_sector(&self, in_partition_bytes_offset: u64) -> u64 { 768 return in_partition_bytes_offset / (self.bpb.bytes_per_sector as u64); 769 } 770 771 /// @brief 根据字节偏移量计算在逻辑块内的字节偏移量 772 #[inline] get_in_block_offset(&self, bytes_offset: u64) -> u64773 pub fn get_in_block_offset(&self, bytes_offset: u64) -> u64 { 774 return bytes_offset % LBA_SIZE as u64; 775 } 776 777 /// @brief 获取在FAT表中，以start_cluster开头的FAT链的所有簇的信息 778 /// 779 /// @param start_cluster 整个FAT链的起始簇号 clusters(&self, start_cluster: Cluster) -> Vec<Cluster>780 pub fn clusters(&self, start_cluster: Cluster) -> Vec<Cluster> { 781 return self.cluster_iter(start_cluster).collect(); 782 } 783 784 /// @brief 获取在FAT表中，以start_cluster开头的FAT链的长度（总计经过多少个簇） 785 /// 786 /// @param start_cluster 整个FAT链的起始簇号 num_clusters_chain(&self, start_cluster: Cluster) -> u64787 pub fn num_clusters_chain(&self, start_cluster: Cluster) -> u64 { 788 return self 789 .cluster_iter(start_cluster) 790 .fold(0, |size, _cluster| size + 1); 791 } 792 /// @brief 获取一个簇迭代器对象 793 /// 794 /// @param start_cluster 整个FAT链的起始簇号 cluster_iter(&self, start_cluster: Cluster) -> ClusterIter795 fn cluster_iter(&self, start_cluster: Cluster) -> ClusterIter { 796 return ClusterIter { 797 current_cluster: Some(start_cluster), 798 fs: self, 799 }; 800 } 801 802 /// @brief 获取从start_cluster开始的簇链中，第n个簇的信息。（请注意，下标从0开始） 803 #[inline] get_cluster_by_relative(&self, start_cluster: Cluster, n: usize) -> Option<Cluster>804 pub fn get_cluster_by_relative(&self, start_cluster: Cluster, n: usize) -> Option<Cluster> { 805 return self.cluster_iter(start_cluster).nth(n); 806 } 807 808 /// @brief 获取整个簇链的最后一个簇 809 #[inline] get_last_cluster(&self, start_cluster: Cluster) -> Option<Cluster>810 pub fn get_last_cluster(&self, start_cluster: Cluster) -> Option<Cluster> { 811 return self.cluster_iter(start_cluster).last(); 812 } 813 814 /// @brief 判断FAT文件系统的shut bit是否正常。 815 /// shut bit 表示文件系统是否正常卸载。如果这一位是1,则表示这个卷是“干净的” 816 /// 参考资料：https://thestarman.pcministry.com/DOS/DirtyShutdownFlag.html 817 /// 818 /// @return Ok(true) 正常 819 /// @return Ok(false) 不正常 820 /// @return Err(SystemError) 在判断时发生错误 821 #[allow(dead_code)] is_shut_bit_ok(&mut self) -> Result<bool, SystemError>822 pub fn is_shut_bit_ok(&mut self) -> Result<bool, SystemError> { 823 match self.bpb.fat_type { 824 FATType::FAT32(_) => { 825 // 对于FAT32, error bit位于第一个扇区的第8字节。 826 let bit = self.get_fat_entry_raw(Cluster::new(1))? & 0x0800_0000; 827 return Ok(bit > 0); 828 } 829 FATType::FAT16(_) => { 830 let bit = self.get_fat_entry_raw(Cluster::new(1))? & 0x8000; 831 return Ok(bit > 0); 832 } 833 _ => return Ok(true), 834 } 835 } 836 837 /// @brief 判断FAT文件系统的hard error bit是否正常。 838 /// 如果此位为0，则文件系统驱动程序在上次安装卷时遇到磁盘 I/O 错误，这表明 839 /// 卷上的某些扇区可能已损坏。 840 /// 参考资料：https://thestarman.pcministry.com/DOS/DirtyShutdownFlag.html 841 /// 842 /// @return Ok(true) 正常 843 /// @return Ok(false) 不正常 844 /// @return Err(SystemError) 在判断时发生错误 845 #[allow(dead_code)] is_hard_error_bit_ok(&mut self) -> Result<bool, SystemError>846 pub fn is_hard_error_bit_ok(&mut self) -> Result<bool, SystemError> { 847 match self.bpb.fat_type { 848 FATType::FAT32(_) => { 849 let bit = self.get_fat_entry_raw(Cluster::new(1))? & 0x0400_0000; 850 return Ok(bit > 0); 851 } 852 FATType::FAT16(_) => { 853 let bit = self.get_fat_entry_raw(Cluster::new(1))? & 0x4000; 854 return Ok(bit > 0); 855 } 856 _ => return Ok(true), 857 } 858 } 859 860 /// @brief 设置文件系统的shut bit为正常状态 861 /// 参考资料：https://thestarman.pcministry.com/DOS/DirtyShutdownFlag.html 862 /// 863 /// @return Ok(()) 设置成功 864 /// @return Err(SystemError) 在设置过程中，出现错误 set_shut_bit_ok(&mut self) -> Result<(), SystemError>865 pub fn set_shut_bit_ok(&mut self) -> Result<(), SystemError> { 866 match self.bpb.fat_type { 867 FATType::FAT32(_) => { 868 let raw_entry = self.get_fat_entry_raw(Cluster::new(1))? | 0x0800_0000; 869 self.set_entry(Cluster::new(1), FATEntry::Next(Cluster::new(raw_entry)))?; 870 871 return Ok(()); 872 } 873 874 FATType::FAT16(_) => { 875 let raw_entry = self.get_fat_entry_raw(Cluster::new(1))? | 0x8000; 876 self.set_entry(Cluster::new(1), FATEntry::Next(Cluster::new(raw_entry)))?; 877 return Ok(()); 878 } 879 _ => return Ok(()), 880 } 881 } 882 883 /// @brief 设置文件系统的hard error bit为正常状态 884 /// 参考资料：https://thestarman.pcministry.com/DOS/DirtyShutdownFlag.html 885 /// 886 /// @return Ok(()) 设置成功 887 /// @return Err(SystemError) 在设置过程中，出现错误 set_hard_error_bit_ok(&mut self) -> Result<(), SystemError>888 pub fn set_hard_error_bit_ok(&mut self) -> Result<(), SystemError> { 889 match self.bpb.fat_type { 890 FATType::FAT32(_) => { 891 let raw_entry = self.get_fat_entry_raw(Cluster::new(1))? | 0x0400_0000; 892 self.set_entry(Cluster::new(1), FATEntry::Next(Cluster::new(raw_entry)))?; 893 return Ok(()); 894 } 895 896 FATType::FAT16(_) => { 897 let raw_entry = self.get_fat_entry_raw(Cluster::new(1))? | 0x4000; 898 self.set_entry(Cluster::new(1), FATEntry::Next(Cluster::new(raw_entry)))?; 899 return Ok(()); 900 } 901 _ => return Ok(()), 902 } 903 } 904 905 /// @brief 执行文件系统卸载前的一些准备工作：设置好对应的标志位，并把缓存中的数据刷入磁盘 umount(&mut self) -> Result<(), SystemError>906 pub fn umount(&mut self) -> Result<(), SystemError> { 907 self.fs_info.0.lock().flush(&self.gendisk)?; 908 909 self.set_shut_bit_ok()?; 910 911 self.set_hard_error_bit_ok()?; 912 913 self.gendisk.sync()?; 914 915 return Ok(()); 916 } 917 918 /// @brief 获取文件系统的最大簇号 max_cluster_number(&self) -> Cluster919 pub fn max_cluster_number(&self) -> Cluster { 920 match self.bpb.fat_type { 921 FATType::FAT32(s) => { 922 // FAT32 923 924 // 数据扇区数量（总扇区数-保留扇区-FAT占用的扇区） 925 let data_sec: u64 = self.bpb.total_sectors_32 as u64 926 - (self.bpb.rsvd_sec_cnt as u64 927 + self.bpb.num_fats as u64 * s.fat_size_32 as u64); 928 929 // 数据区的簇数量 930 let total_clusters: u64 = data_sec / self.bpb.sector_per_cluster as u64; 931 932 // 返回最大的簇号 933 return Cluster::new(total_clusters + RESERVED_CLUSTERS as u64 - 1); 934 } 935 936 _ => { 937 // FAT12 / FAT16 938 let root_dir_sectors: u64 = ((self.bpb.root_entries_cnt as u64) * 32) 939 .div_ceil(self.bpb.bytes_per_sector as u64); 940 // 数据区扇区数 941 let data_sec: u64 = self.bpb.total_sectors_16 as u64 942 - (self.bpb.rsvd_sec_cnt as u64 943 + (self.bpb.num_fats as u64 * self.bpb.fat_size_16 as u64) 944 + root_dir_sectors); 945 let total_clusters = data_sec / self.bpb.sector_per_cluster as u64; 946 return Cluster::new(total_clusters + RESERVED_CLUSTERS as u64 - 1); 947 } 948 } 949 } 950 951 /// @brief 在文件系统中寻找一个簇号在给定的范围（左闭右开区间）内的空闲簇 952 /// 953 /// @param start_cluster 起始簇号 954 /// @param end_cluster 终止簇号（不包含） 955 /// 956 /// @return Ok(Cluster) 寻找到的空闲簇 957 /// @return Err(SystemError) 错误码。如果磁盘无剩余空间，或者簇号达到给定的最大值，则返回-ENOSPC. get_free_cluster( &self, start_cluster: Cluster, end_cluster: Cluster, ) -> Result<Cluster, SystemError>958 pub fn get_free_cluster( 959 &self, 960 start_cluster: Cluster, 961 end_cluster: Cluster, 962 ) -> Result<Cluster, SystemError> { 963 let max_cluster: Cluster = self.max_cluster_number(); 964 let mut cluster: u64 = start_cluster.cluster_num; 965 966 let fat_type: FATType = self.bpb.fat_type; 967 let fat_start_sector: u64 = self.fat_start_sector(); 968 let bytes_per_sec: u64 = self.bpb.bytes_per_sector as u64; 969 970 match fat_type { 971 FATType::FAT12(_) => { 972 let part_bytes_offset: u64 = 973 fat_type.get_fat_bytes_offset(start_cluster, fat_start_sector, bytes_per_sec); 974 let in_block_offset = self.get_in_block_offset(part_bytes_offset); 975 976 let lba = self.gendisk_lba_from_offset(self.bytes_to_sector(part_bytes_offset)); 977 978 // 由于FAT12的FAT表不大于6K，因此直接读取6K 979 let num_lba = (6 * 1024) / LBA_SIZE; 980 let mut v: Vec<u8> = vec![0; num_lba * LBA_SIZE]; 981 self.gendisk.read_at(&mut v, lba)?; 982 983 let mut cursor: VecCursor = VecCursor::new(v); 984 cursor.seek(SeekFrom::SeekSet(in_block_offset as i64))?; 985 986 let mut packed_val: u16 = cursor.read_u16()?; 987 loop { 988 let val = if (cluster & 0x1) > 0 { 989 packed_val >> 4 990 } else { 991 packed_val & 0x0fff 992 }; 993 if val == 0 { 994 return Ok(Cluster::new(cluster)); 995 } 996 997 cluster += 1; 998 999 // 磁盘无剩余空间，或者簇号达到给定的最大值 1000 if cluster == end_cluster.cluster_num || cluster == max_cluster.cluster_num { 1001 return Err(SystemError::ENOSPC); 1002 } 1003 1004 packed_val = match cluster & 1 { 1005 0 => cursor.read_u16()?, 1006 _ => { 1007 let next_byte = cursor.read_u8()? as u16; 1008 (packed_val >> 8) | (next_byte << 8) 1009 } 1010 }; 1011 } 1012 } 1013 FATType::FAT16(_) => { 1014 // todo: 优化这里，减少读取磁盘的次数。 1015 while cluster < end_cluster.cluster_num && cluster < max_cluster.cluster_num { 1016 let part_bytes_offset: u64 = fat_type.get_fat_bytes_offset( 1017 Cluster::new(cluster), 1018 fat_start_sector, 1019 bytes_per_sec, 1020 ); 1021 let in_block_offset = self.get_in_block_offset(part_bytes_offset); 1022 1023 let lba = self.gendisk_lba_from_offset(self.bytes_to_sector(part_bytes_offset)); 1024 1025 let mut v: Vec<u8> = vec![0; self.lba_per_sector() * LBA_SIZE]; 1026 self.gendisk.read_at(&mut v, lba)?; 1027 1028 let mut cursor: VecCursor = VecCursor::new(v); 1029 cursor.seek(SeekFrom::SeekSet(in_block_offset as i64))?; 1030 1031 let val = cursor.read_u16()?; 1032 // 找到空闲簇 1033 if val == 0 { 1034 return Ok(Cluster::new(val as u64)); 1035 } 1036 cluster += 1; 1037 } 1038 1039 // 磁盘无剩余空间，或者簇号达到给定的最大值 1040 return Err(SystemError::ENOSPC); 1041 } 1042 FATType::FAT32(_) => { 1043 // todo: 优化这里，减少读取磁盘的次数。 1044 while cluster < end_cluster.cluster_num && cluster < max_cluster.cluster_num { 1045 let part_bytes_offset: u64 = fat_type.get_fat_bytes_offset( 1046 Cluster::new(cluster), 1047 fat_start_sector, 1048 bytes_per_sec, 1049 ); 1050 let in_block_offset = self.get_in_block_offset(part_bytes_offset); 1051 1052 let lba = self.gendisk_lba_from_offset(self.bytes_to_sector(part_bytes_offset)); 1053 1054 let mut v: Vec<u8> = vec![0; self.lba_per_sector() * LBA_SIZE]; 1055 self.gendisk.read_at(&mut v, lba)?; 1056 1057 let mut cursor: VecCursor = VecCursor::new(v); 1058 cursor.seek(SeekFrom::SeekSet(in_block_offset as i64))?; 1059 1060 let val = cursor.read_u32()? & 0x0fffffff; 1061 1062 if val == 0 { 1063 return Ok(Cluster::new(cluster)); 1064 } 1065 cluster += 1; 1066 } 1067 1068 // 磁盘无剩余空间，或者簇号达到给定的最大值 1069 return Err(SystemError::ENOSPC); 1070 } 1071 } 1072 } 1073 1074 /// @brief 在FAT表中，设置指定的簇的信息。 1075 /// 1076 /// @param cluster 目标簇 1077 /// @param fat_entry 这个簇在FAT表中，存储的信息（下一个簇的簇号） set_entry(&self, cluster: Cluster, fat_entry: FATEntry) -> Result<(), SystemError>1078 pub fn set_entry(&self, cluster: Cluster, fat_entry: FATEntry) -> Result<(), SystemError> { 1079 // fat表项在分区上的字节偏移量 1080 let fat_part_bytes_offset: u64 = self.bpb.fat_type.get_fat_bytes_offset( 1081 cluster, 1082 self.fat_start_sector(), 1083 self.bpb.bytes_per_sector as u64, 1084 ); 1085 1086 match self.bpb.fat_type { 1087 FATType::FAT12(_) => { 1088 // 计算要写入的值 1089 let raw_val: u16 = match fat_entry { 1090 FATEntry::Unused => 0, 1091 FATEntry::Bad => 0xff7, 1092 FATEntry::EndOfChain => 0xfff, 1093 FATEntry::Next(c) => c.cluster_num as u16, 1094 }; 1095 1096 let in_block_offset = self.get_in_block_offset(fat_part_bytes_offset); 1097 1098 let lba = self.gendisk_lba_from_offset(self.bytes_to_sector(fat_part_bytes_offset)); 1099 1100 let mut v: Vec<u8> = vec![0; LBA_SIZE]; 1101 self.gendisk.read_at(&mut v, lba)?; 1102 1103 let mut cursor: VecCursor = VecCursor::new(v); 1104 cursor.seek(SeekFrom::SeekSet(in_block_offset as i64))?; 1105 1106 let old_val: u16 = cursor.read_u16()?; 1107 let new_val: u16 = if (cluster.cluster_num & 0x1) > 0 { 1108 (old_val & 0x000f) | (raw_val << 4) 1109 } else { 1110 (old_val & 0xf000) | raw_val 1111 }; 1112 1113 // 写回数据到磁盘上 1114 cursor.seek(SeekFrom::SeekSet(in_block_offset as i64))?; 1115 cursor.write_u16(new_val)?; 1116 self.gendisk.write_at(cursor.as_slice(), lba)?; 1117 return Ok(()); 1118 } 1119 FATType::FAT16(_) => { 1120 // 计算要写入的值 1121 let raw_val: u16 = match fat_entry { 1122 FATEntry::Unused => 0, 1123 FATEntry::Bad => 0xfff7, 1124 FATEntry::EndOfChain => 0xfdff, 1125 FATEntry::Next(c) => c.cluster_num as u16, 1126 }; 1127 1128 let in_block_offset = self.get_in_block_offset(fat_part_bytes_offset); 1129 1130 let lba = self.gendisk_lba_from_offset(self.bytes_to_sector(fat_part_bytes_offset)); 1131 1132 let mut v: Vec<u8> = vec![0; LBA_SIZE]; 1133 self.gendisk.read_at(&mut v, lba)?; 1134 1135 let mut cursor: VecCursor = VecCursor::new(v); 1136 cursor.seek(SeekFrom::SeekSet(in_block_offset as i64))?; 1137 1138 cursor.write_u16(raw_val)?; 1139 self.gendisk.write_at(cursor.as_slice(), lba)?; 1140 1141 return Ok(()); 1142 } 1143 FATType::FAT32(_) => { 1144 let fat_size: u64 = self.fat_size(); 1145 let bound: u64 = if self.mirroring_enabled() { 1146 1 1147 } else { 1148 self.bpb.num_fats as u64 1149 }; 1150 // debug!("set entry, bound={bound}, fat_size={fat_size}"); 1151 for i in 0..bound { 1152 // 当前操作的FAT表在磁盘上的字节偏移量 1153 let f_offset: u64 = fat_part_bytes_offset + i * fat_size; 1154 let in_block_offset: u64 = self.get_in_block_offset(f_offset); 1155 let lba = self.gendisk_lba_from_offset(self.bytes_to_sector(f_offset)); 1156 1157 // debug!("set entry, lba={lba}, in_block_offset={in_block_offset}"); 1158 let mut v: Vec<u8> = vec![0; LBA_SIZE]; 1159 self.gendisk.read_at(&mut v, lba)?; 1160 1161 let mut cursor: VecCursor = VecCursor::new(v); 1162 cursor.seek(SeekFrom::SeekSet(in_block_offset as i64))?; 1163 1164 // FAT32的高4位保留 1165 let old_bits = cursor.read_u32()? & 0xf0000000; 1166 1167 if fat_entry == FATEntry::Unused 1168 && cluster.cluster_num >= 0x0ffffff7 1169 && cluster.cluster_num <= 0x0fffffff 1170 { 1171 error!( 1172 "FAT32: Reserved Cluster {:?} cannot be marked as free", 1173 cluster 1174 ); 1175 return Err(SystemError::EPERM); 1176 } 1177 1178 // 计算要写入的值 1179 let mut raw_val: u32 = match fat_entry { 1180 FATEntry::Unused => 0, 1181 FATEntry::Bad => 0x0FFFFFF7, 1182 FATEntry::EndOfChain => 0x0FFFFFFF, 1183 FATEntry::Next(c) => c.cluster_num as u32, 1184 }; 1185 1186 // 恢复保留位 1187 raw_val |= old_bits; 1188 1189 // debug!("sent entry, raw_val={raw_val}"); 1190 1191 cursor.seek(SeekFrom::SeekSet(in_block_offset as i64))?; 1192 cursor.write_u32(raw_val)?; 1193 1194 self.gendisk.write_at(cursor.as_slice(), lba)?; 1195 } 1196 1197 return Ok(()); 1198 } 1199 } 1200 } 1201 1202 /// # 清空指定的簇 1203 /// 1204 /// # 参数 1205 /// - cluster 要被清空的簇 zero_cluster(&self, cluster: Cluster) -> Result<(), SystemError>1206 pub fn zero_cluster(&self, cluster: Cluster) -> Result<(), SystemError> { 1207 // 准备数据，用于写入 1208 let zeros: Vec<u8> = vec![0u8; self.bytes_per_cluster() as usize]; 1209 let offset = self.cluster_bytes_offset(cluster) as usize; 1210 self.gendisk.write_at_bytes(&zeros, offset)?; 1211 return Ok(()); 1212 } 1213 } 1214 1215 impl Drop for FATFileSystem { drop(&mut self)1216 fn drop(&mut self) { 1217 let r = self.umount(); 1218 if r.is_err() { 1219 error!( 1220 "Umount FAT filesystem failed: errno={:?}, FS detail:{self:?}", 1221 r.as_ref().unwrap_err() 1222 ); 1223 } 1224 } 1225 } 1226 1227 impl FATFsInfo { 1228 const LEAD_SIG: u32 = 0x41615252; 1229 const STRUC_SIG: u32 = 0x61417272; 1230 const TRAIL_SIG: u32 = 0xAA550000; 1231 #[allow(dead_code)] 1232 const FS_INFO_SIZE: u64 = 512; 1233 1234 /// @brief 从磁盘上读取FAT文件系统的FSInfo结构体 1235 /// 1236 /// @param partition 磁盘分区 1237 /// @param in_gendisk_fs_info_offset FSInfo扇区在gendisk内的字节偏移量（单位：字节） 1238 /// @param bytes_per_sec 每扇区字节数 new( gendisk: &Arc<GenDisk>, in_gendisk_fs_info_offset: usize, bytes_per_sec: usize, ) -> Result<Self, SystemError>1239 pub fn new( 1240 gendisk: &Arc<GenDisk>, 1241 in_gendisk_fs_info_offset: usize, 1242 bytes_per_sec: usize, 1243 ) -> Result<Self, SystemError> { 1244 let mut v = vec![0; bytes_per_sec]; 1245 1246 // 读取磁盘上的FsInfo扇区 1247 gendisk.read_at_bytes(&mut v, in_gendisk_fs_info_offset)?; 1248 1249 let mut cursor = VecCursor::new(v); 1250 1251 let mut fsinfo = FATFsInfo { 1252 lead_sig: cursor.read_u32()?, 1253 ..Default::default() 1254 }; 1255 cursor.seek(SeekFrom::SeekCurrent(480))?; 1256 fsinfo.struc_sig = cursor.read_u32()?; 1257 fsinfo.free_count = cursor.read_u32()?; 1258 fsinfo.next_free = cursor.read_u32()?; 1259 1260 cursor.seek(SeekFrom::SeekCurrent(12))?; 1261 1262 fsinfo.trail_sig = cursor.read_u32()?; 1263 fsinfo.dirty = false; 1264 fsinfo.offset = Some(gendisk.disk_bytes_offset(in_gendisk_fs_info_offset) as u64); 1265 1266 if fsinfo.is_valid() { 1267 return Ok(fsinfo); 1268 } else { 1269 error!("Error occurred while parsing FATFsInfo."); 1270 return Err(SystemError::EINVAL); 1271 } 1272 } 1273 1274 /// @brief 判断是否为正确的FsInfo结构体 is_valid(&self) -> bool1275 fn is_valid(&self) -> bool { 1276 self.lead_sig == Self::LEAD_SIG 1277 && self.struc_sig == Self::STRUC_SIG 1278 && self.trail_sig == Self::TRAIL_SIG 1279 } 1280 1281 /// @brief 根据fsinfo的信息，计算当前总的空闲簇数量 1282 /// 1283 /// @param 当前文件系统的最大簇号 1284 #[allow(dead_code)] count_free_cluster(&self, max_cluster: Cluster) -> Option<u64>1285 pub fn count_free_cluster(&self, max_cluster: Cluster) -> Option<u64> { 1286 let count_clusters = max_cluster.cluster_num - RESERVED_CLUSTERS as u64 + 1; 1287 // 信息不合理，当前的FsInfo中存储的free count大于计算出来的值 1288 if self.free_count as u64 > count_clusters { 1289 return None; 1290 } else { 1291 match self.free_count { 1292 // free count字段不可用 1293 0xffffffff => return None, 1294 // 返回FsInfo中存储的数据 1295 n => return Some(n as u64), 1296 } 1297 } 1298 } 1299 1300 /// @brief 更新FsInfo中的“空闲簇统计信息“为new_count 1301 /// 1302 /// 请注意，除非手动调用`flush()`，否则本函数不会将数据刷入磁盘 1303 #[allow(dead_code)] update_free_count_abs(&mut self, new_count: u32)1304 pub fn update_free_count_abs(&mut self, new_count: u32) { 1305 self.free_count = new_count; 1306 } 1307 1308 /// @brief 更新FsInfo中的“空闲簇统计信息“，把它加上delta. 1309 /// 1310 /// 请注意，除非手动调用`flush()`，否则本函数不会将数据刷入磁盘 1311 #[allow(dead_code)] update_free_count_delta(&mut self, delta: i32)1312 pub fn update_free_count_delta(&mut self, delta: i32) { 1313 self.free_count = (self.free_count as i32 + delta) as u32; 1314 } 1315 1316 /// @brief 更新FsInfo中的“第一个空闲簇统计信息“为next_free. 1317 /// 1318 /// 请注意，除非手动调用`flush()`，否则本函数不会将数据刷入磁盘 update_next_free(&mut self, next_free: u32)1319 pub fn update_next_free(&mut self, next_free: u32) { 1320 // 这个值是参考量，不一定要准确，仅供加速查找 1321 self.next_free = next_free; 1322 } 1323 1324 /// @brief 获取fs info 记载的第一个空闲簇。（不一定准确，仅供参考） next_free(&self) -> Option<u64>1325 pub fn next_free(&self) -> Option<u64> { 1326 match self.next_free { 1327 0xffffffff => return None, 1328 0 | 1 => return None, 1329 n => return Some(n as u64), 1330 }; 1331 } 1332 1333 /// @brief 把fs info刷入磁盘 1334 /// 1335 /// @param partition fs info所在的分区 flush(&self, gendisk: &Arc<GenDisk>) -> Result<(), SystemError>1336 pub fn flush(&self, gendisk: &Arc<GenDisk>) -> Result<(), SystemError> { 1337 if let Some(off) = self.offset { 1338 let in_block_offset = off % LBA_SIZE as u64; 1339 1340 let lba = off as usize / LBA_SIZE; 1341 1342 let mut v: Vec<u8> = vec![0; LBA_SIZE]; 1343 gendisk.read_at(&mut v, lba)?; 1344 1345 let mut cursor: VecCursor = VecCursor::new(v); 1346 cursor.seek(SeekFrom::SeekSet(in_block_offset as i64))?; 1347 1348 cursor.write_u32(self.lead_sig)?; 1349 cursor.seek(SeekFrom::SeekCurrent(480))?; 1350 cursor.write_u32(self.struc_sig)?; 1351 cursor.write_u32(self.free_count)?; 1352 cursor.write_u32(self.next_free)?; 1353 cursor.seek(SeekFrom::SeekCurrent(12))?; 1354 cursor.write_u32(self.trail_sig)?; 1355 1356 gendisk.write_at(cursor.as_slice(), lba)?; 1357 } 1358 return Ok(()); 1359 } 1360 1361 /// @brief 读取磁盘上的Fs Info扇区，将里面的内容更新到结构体中 1362 /// 1363 /// @param partition fs info所在的分区 1364 #[allow(dead_code)] update(&mut self, partition: Arc<Partition>) -> Result<(), SystemError>1365 pub fn update(&mut self, partition: Arc<Partition>) -> Result<(), SystemError> { 1366 if let Some(off) = self.offset { 1367 let in_block_offset = off % LBA_SIZE as u64; 1368 1369 let lba = off as usize / LBA_SIZE; 1370 1371 let mut v: Vec<u8> = vec![0; LBA_SIZE]; 1372 partition.disk().read_at(lba, 1, &mut v)?; 1373 let mut cursor: VecCursor = VecCursor::new(v); 1374 cursor.seek(SeekFrom::SeekSet(in_block_offset as i64))?; 1375 self.lead_sig = cursor.read_u32()?; 1376 1377 cursor.seek(SeekFrom::SeekCurrent(480))?; 1378 self.struc_sig = cursor.read_u32()?; 1379 self.free_count = cursor.read_u32()?; 1380 self.next_free = cursor.read_u32()?; 1381 cursor.seek(SeekFrom::SeekCurrent(12))?; 1382 self.trail_sig = cursor.read_u32()?; 1383 } 1384 return Ok(()); 1385 } 1386 } 1387 1388 impl IndexNode for LockedFATInode { read_at( &self, offset: usize, len: usize, buf: &mut [u8], _data: SpinLockGuard<FilePrivateData>, ) -> Result<usize, SystemError>1389 fn read_at( 1390 &self, 1391 offset: usize, 1392 len: usize, 1393 buf: &mut [u8], 1394 _data: SpinLockGuard<FilePrivateData>, 1395 ) -> Result<usize, SystemError> { 1396 let mut guard: SpinLockGuard<FATInode> = self.0.lock(); 1397 match &guard.inode_type { 1398 FATDirEntry::File(f) | FATDirEntry::VolId(f) => { 1399 let r = f.read( 1400 &guard.fs.upgrade().unwrap(), 1401 &mut buf[0..len], 1402 offset as u64, 1403 ); 1404 guard.update_metadata(); 1405 return r; 1406 } 1407 FATDirEntry::Dir(_) => { 1408 return Err(SystemError::EISDIR); 1409 } 1410 FATDirEntry::UnInit => { 1411 error!("FATFS: param: Inode_type uninitialized."); 1412 return Err(SystemError::EROFS); 1413 } 1414 } 1415 } 1416 write_at( &self, offset: usize, len: usize, buf: &[u8], _data: SpinLockGuard<FilePrivateData>, ) -> Result<usize, SystemError>1417 fn write_at( 1418 &self, 1419 offset: usize, 1420 len: usize, 1421 buf: &[u8], 1422 _data: SpinLockGuard<FilePrivateData>, 1423 ) -> Result<usize, SystemError> { 1424 let mut guard: SpinLockGuard<FATInode> = self.0.lock(); 1425 let fs: &Arc<FATFileSystem> = &guard.fs.upgrade().unwrap(); 1426 1427 match &mut guard.inode_type { 1428 FATDirEntry::File(f) | FATDirEntry::VolId(f) => { 1429 let r = f.write(fs, &buf[0..len], offset as u64); 1430 guard.update_metadata(); 1431 return r; 1432 } 1433 FATDirEntry::Dir(_) => { 1434 return Err(SystemError::EISDIR); 1435 } 1436 FATDirEntry::UnInit => { 1437 error!("FATFS: param: Inode_type uninitialized."); 1438 return Err(SystemError::EROFS); 1439 } 1440 } 1441 } 1442 create( &self, name: &str, file_type: FileType, _mode: ModeType, ) -> Result<Arc<dyn IndexNode>, SystemError>1443 fn create( 1444 &self, 1445 name: &str, 1446 file_type: FileType, 1447 _mode: ModeType, 1448 ) -> Result<Arc<dyn IndexNode>, SystemError> { 1449 // 由于FAT32不支持文件权限的功能，因此忽略mode参数 1450 let mut guard: SpinLockGuard<FATInode> = self.0.lock(); 1451 let fs: &Arc<FATFileSystem> = &guard.fs.upgrade().unwrap(); 1452 1453 match &mut guard.inode_type { 1454 FATDirEntry::File(_) | FATDirEntry::VolId(_) => { 1455 return Err(SystemError::ENOTDIR); 1456 } 1457 FATDirEntry::Dir(d) => match file_type { 1458 FileType::File => { 1459 d.create_file(name, fs)?; 1460 return Ok(guard.find(name)?); 1461 } 1462 FileType::Dir => { 1463 d.create_dir(name, fs)?; 1464 return Ok(guard.find(name)?); 1465 } 1466 1467 FileType::SymLink => return Err(SystemError::ENOSYS), 1468 _ => return Err(SystemError::EINVAL), 1469 }, 1470 FATDirEntry::UnInit => { 1471 error!("FATFS: param: Inode_type uninitialized."); 1472 return Err(SystemError::EROFS); 1473 } 1474 } 1475 } 1476 fs(&self) -> Arc<dyn FileSystem>1477 fn fs(&self) -> Arc<dyn FileSystem> { 1478 return self.0.lock().fs.upgrade().unwrap(); 1479 } 1480 as_any_ref(&self) -> &dyn core::any::Any1481 fn as_any_ref(&self) -> &dyn core::any::Any { 1482 return self; 1483 } 1484 metadata(&self) -> Result<Metadata, SystemError>1485 fn metadata(&self) -> Result<Metadata, SystemError> { 1486 return Ok(self.0.lock().metadata.clone()); 1487 } set_metadata(&self, metadata: &Metadata) -> Result<(), SystemError>1488 fn set_metadata(&self, metadata: &Metadata) -> Result<(), SystemError> { 1489 let inode = &mut self.0.lock(); 1490 inode.metadata.atime = metadata.atime; 1491 inode.metadata.mtime = metadata.mtime; 1492 inode.metadata.ctime = metadata.ctime; 1493 inode.metadata.mode = metadata.mode; 1494 inode.metadata.uid = metadata.uid; 1495 inode.metadata.gid = metadata.gid; 1496 Ok(()) 1497 } resize(&self, len: usize) -> Result<(), SystemError>1498 fn resize(&self, len: usize) -> Result<(), SystemError> { 1499 let mut guard: SpinLockGuard<FATInode> = self.0.lock(); 1500 let fs: &Arc<FATFileSystem> = &guard.fs.upgrade().unwrap(); 1501 let old_size = guard.metadata.size as usize; 1502 1503 match &mut guard.inode_type { 1504 FATDirEntry::File(file) | FATDirEntry::VolId(file) => { 1505 // 如果新的长度和旧的长度相同，那么就直接返回 1506 match len.cmp(&old_size) { 1507 Ordering::Equal => { 1508 return Ok(()); 1509 } 1510 Ordering::Greater => { 1511 // 如果新的长度比旧的长度大，那么就在文件末尾添加空白 1512 let mut buf: Vec<u8> = Vec::new(); 1513 let mut remain_size = len - old_size; 1514 let buf_size = remain_size; 1515 // let buf_size = core::cmp::min(remain_size, 512 * 1024); 1516 buf.resize(buf_size, 0); 1517 1518 let mut offset = old_size; 1519 while remain_size > 0 { 1520 let write_size = core::cmp::min(remain_size, buf_size); 1521 file.write(fs, &buf[0..write_size], offset as u64)?; 1522 remain_size -= write_size; 1523 offset += write_size; 1524 } 1525 } 1526 Ordering::Less => { 1527 file.truncate(fs, len as u64)?; 1528 } 1529 } 1530 guard.update_metadata(); 1531 return Ok(()); 1532 } 1533 FATDirEntry::Dir(_) => return Err(SystemError::ENOSYS), 1534 FATDirEntry::UnInit => { 1535 error!("FATFS: param: Inode_type uninitialized."); 1536 return Err(SystemError::EROFS); 1537 } 1538 } 1539 } 1540 truncate(&self, len: usize) -> Result<(), SystemError>1541 fn truncate(&self, len: usize) -> Result<(), SystemError> { 1542 let guard: SpinLockGuard<FATInode> = self.0.lock(); 1543 let old_size = guard.metadata.size as usize; 1544 if len < old_size { 1545 drop(guard); 1546 self.resize(len) 1547 } else { 1548 Ok(()) 1549 } 1550 } 1551 list(&self) -> Result<Vec<String>, SystemError>1552 fn list(&self) -> Result<Vec<String>, SystemError> { 1553 let mut guard: SpinLockGuard<FATInode> = self.0.lock(); 1554 let fatent: &FATDirEntry = &guard.inode_type; 1555 match fatent { 1556 FATDirEntry::File(_) | FATDirEntry::VolId(_) => { 1557 return Err(SystemError::ENOTDIR); 1558 } 1559 FATDirEntry::Dir(dir) => { 1560 // 获取当前目录下的所有目录项 1561 let mut ret: Vec<String> = Vec::new(); 1562 let dir_iter: FATDirIter = dir.to_iter(guard.fs.upgrade().unwrap()); 1563 for ent in dir_iter { 1564 ret.push(ent.name()); 1565 1566 // ====== 生成inode缓存 1567 let search_name = to_search_name_string(ent.name()); 1568 // debug!("name={name}"); 1569 1570 if !guard.children.contains_key(&search_name) 1571 && search_name != "." 1572 && search_name != ".." 1573 { 1574 let name = DName::from(ent.name()); 1575 // 创建新的inode 1576 let entry_inode: Arc<LockedFATInode> = LockedFATInode::new( 1577 name.clone(), 1578 guard.fs.upgrade().unwrap(), 1579 guard.self_ref.clone(), 1580 ent, 1581 ); 1582 // 加入缓存区, 由于FAT文件系统的大小写不敏感问题，因此存入缓存区的key应当是全大写的 1583 guard.children.insert(search_name, entry_inode.clone()); 1584 } 1585 } 1586 return Ok(ret); 1587 } 1588 FATDirEntry::UnInit => { 1589 error!("FATFS: param: Inode_type uninitialized."); 1590 return Err(SystemError::EROFS); 1591 } 1592 } 1593 } 1594 find(&self, name: &str) -> Result<Arc<dyn IndexNode>, SystemError>1595 fn find(&self, name: &str) -> Result<Arc<dyn IndexNode>, SystemError> { 1596 let mut guard: SpinLockGuard<FATInode> = self.0.lock(); 1597 let target = guard.find(name)?; 1598 return Ok(target); 1599 } 1600 open( &self, _data: SpinLockGuard<FilePrivateData>, _mode: &FileMode, ) -> Result<(), SystemError>1601 fn open( 1602 &self, 1603 _data: SpinLockGuard<FilePrivateData>, 1604 _mode: &FileMode, 1605 ) -> Result<(), SystemError> { 1606 return Ok(()); 1607 } 1608 close(&self, _data: SpinLockGuard<FilePrivateData>) -> Result<(), SystemError>1609 fn close(&self, _data: SpinLockGuard<FilePrivateData>) -> Result<(), SystemError> { 1610 return Ok(()); 1611 } 1612 unlink(&self, name: &str) -> Result<(), SystemError>1613 fn unlink(&self, name: &str) -> Result<(), SystemError> { 1614 let mut guard: SpinLockGuard<FATInode> = self.0.lock(); 1615 let target: Arc<LockedFATInode> = guard.find(name)?; 1616 // 对目标inode上锁，以防更改 1617 let target_guard: SpinLockGuard<FATInode> = target.0.lock(); 1618 // 先从缓存删除 1619 let nod = guard.children.remove(&to_search_name(name)); 1620 1621 // 若删除缓存中为管道的文件，则不需要再到磁盘删除 1622 if nod.is_some() { 1623 let file_type = target_guard.metadata.file_type; 1624 if file_type == FileType::Pipe { 1625 return Ok(()); 1626 } 1627 } 1628 1629 let dir = match &guard.inode_type { 1630 FATDirEntry::File(_) | FATDirEntry::VolId(_) => { 1631 return Err(SystemError::ENOTDIR); 1632 } 1633 FATDirEntry::Dir(d) => d, 1634 FATDirEntry::UnInit => { 1635 error!("FATFS: param: Inode_type uninitialized."); 1636 return Err(SystemError::EROFS); 1637 } 1638 }; 1639 // 检查文件是否存在 1640 dir.check_existence(name, Some(false), guard.fs.upgrade().unwrap())?; 1641 1642 // 再从磁盘删除 1643 let r = dir.remove(guard.fs.upgrade().unwrap().clone(), name, true); 1644 drop(target_guard); 1645 return r; 1646 } 1647 rmdir(&self, name: &str) -> Result<(), SystemError>1648 fn rmdir(&self, name: &str) -> Result<(), SystemError> { 1649 let mut guard: SpinLockGuard<FATInode> = self.0.lock(); 1650 let target: Arc<LockedFATInode> = guard.find(name)?; 1651 // 对目标inode上锁，以防更改 1652 let target_guard: SpinLockGuard<FATInode> = target.0.lock(); 1653 // 先从缓存删除 1654 guard.children.remove(&to_search_name(name)); 1655 1656 let dir = match &guard.inode_type { 1657 FATDirEntry::File(_) | FATDirEntry::VolId(_) => { 1658 return Err(SystemError::ENOTDIR); 1659 } 1660 FATDirEntry::Dir(d) => d, 1661 FATDirEntry::UnInit => { 1662 error!("FATFS: param: Inode_type uninitialized."); 1663 return Err(SystemError::EROFS); 1664 } 1665 }; 1666 // 检查文件夹是否存在 1667 dir.check_existence(name, Some(true), guard.fs.upgrade().unwrap())?; 1668 1669 // 再从磁盘删除 1670 let r: Result<(), SystemError> = 1671 dir.remove(guard.fs.upgrade().unwrap().clone(), name, true); 1672 match r { 1673 Ok(_) => return r, 1674 Err(r) => { 1675 if r == SystemError::ENOTEMPTY { 1676 // 如果要删除的是目录，且不为空，则删除动作未发生，重新加入缓存 1677 guard.children.insert(to_search_name(name), target.clone()); 1678 drop(target_guard); 1679 } 1680 return Err(r); 1681 } 1682 } 1683 } 1684 move_to( &self, old_name: &str, target: &Arc<dyn IndexNode>, new_name: &str, ) -> Result<(), SystemError>1685 fn move_to( 1686 &self, 1687 old_name: &str, 1688 target: &Arc<dyn IndexNode>, 1689 new_name: &str, 1690 ) -> Result<(), SystemError> { 1691 let old_id = self.metadata().unwrap().inode_id; 1692 let new_id = target.metadata().unwrap().inode_id; 1693 // 若在同一父目录下 1694 if old_id == new_id { 1695 let mut guard = self.0.lock(); 1696 let old_inode: Arc<LockedFATInode> = guard.find(old_name)?; 1697 // 对目标inode上锁，以防更改 1698 let old_inode_guard: SpinLockGuard<FATInode> = old_inode.0.lock(); 1699 let fs = old_inode_guard.fs.upgrade().unwrap(); 1700 // 从缓存删除 1701 let old_dir = match &guard.inode_type { 1702 FATDirEntry::File(_) | FATDirEntry::VolId(_) => { 1703 return Err(SystemError::ENOTDIR); 1704 } 1705 FATDirEntry::Dir(d) => d, 1706 FATDirEntry::UnInit => { 1707 error!("FATFS: param: Inode_type uninitialized."); 1708 return Err(SystemError::EROFS); 1709 } 1710 }; 1711 // 检查文件是否存在 1712 // old_dir.check_existence(old_name, Some(false), guard.fs.upgrade().unwrap())?; 1713 1714 old_dir.rename(fs, old_name, new_name)?; 1715 let _nod = guard.children.remove(&to_search_name(old_name)); 1716 } else { 1717 let mut old_guard = self.0.lock(); 1718 let other: &LockedFATInode = target 1719 .downcast_ref::<LockedFATInode>() 1720 .ok_or(SystemError::EPERM)?; 1721 1722 let new_guard = other.0.lock(); 1723 let old_inode: Arc<LockedFATInode> = old_guard.find(old_name)?; 1724 // 对目标inode上锁，以防更改 1725 let old_inode_guard: SpinLockGuard<FATInode> = old_inode.0.lock(); 1726 let fs = old_inode_guard.fs.upgrade().unwrap(); 1727 1728 let old_dir = match &old_guard.inode_type { 1729 FATDirEntry::File(_) | FATDirEntry::VolId(_) => { 1730 return Err(SystemError::ENOTDIR); 1731 } 1732 FATDirEntry::Dir(d) => d, 1733 FATDirEntry::UnInit => { 1734 error!("FATFS: param: Inode_type uninitialized."); 1735 return Err(SystemError::EROFS); 1736 } 1737 }; 1738 let new_dir = match &new_guard.inode_type { 1739 FATDirEntry::File(_) | FATDirEntry::VolId(_) => { 1740 return Err(SystemError::ENOTDIR); 1741 } 1742 FATDirEntry::Dir(d) => d, 1743 FATDirEntry::UnInit => { 1744 error!("FATFA: param: Inode_type uninitialized."); 1745 return Err(SystemError::EROFS); 1746 } 1747 }; 1748 // 检查文件是否存在 1749 old_dir.check_existence(old_name, Some(false), old_guard.fs.upgrade().unwrap())?; 1750 old_dir.rename_across(fs, new_dir, old_name, new_name)?; 1751 // 从缓存删除 1752 let _nod = old_guard.children.remove(&to_search_name(old_name)); 1753 } 1754 1755 return Ok(()); 1756 } 1757 get_entry_name(&self, ino: InodeId) -> Result<String, SystemError>1758 fn get_entry_name(&self, ino: InodeId) -> Result<String, SystemError> { 1759 let guard: SpinLockGuard<FATInode> = self.0.lock(); 1760 if guard.metadata.file_type != FileType::Dir { 1761 return Err(SystemError::ENOTDIR); 1762 } 1763 match ino.into() { 1764 0 => { 1765 return Ok(String::from(".")); 1766 } 1767 1 => { 1768 return Ok(String::from("..")); 1769 } 1770 ino => { 1771 // 暴力遍历所有的children，判断inode id是否相同 1772 // TODO: 优化这里，这个地方性能很差！ 1773 let mut key: Vec<String> = guard 1774 .children 1775 .iter() 1776 .filter_map(|(k, v)| { 1777 if v.0.lock().metadata.inode_id.into() == ino { 1778 Some(k.to_string()) 1779 } else { 1780 None 1781 } 1782 }) 1783 .collect(); 1784 1785 match key.len() { 1786 0=>{return Err(SystemError::ENOENT);} 1787 1=>{return Ok(key.remove(0));} 1788 _ => panic!("FatFS get_entry_name: key.len()={key_len}>1, current inode_id={inode_id:?}, to find={to_find:?}", key_len=key.len(), inode_id = guard.metadata.inode_id, to_find=ino) 1789 } 1790 } 1791 } 1792 } 1793 mknod( &self, filename: &str, mode: ModeType, _dev_t: DeviceNumber, ) -> Result<Arc<dyn IndexNode>, SystemError>1794 fn mknod( 1795 &self, 1796 filename: &str, 1797 mode: ModeType, 1798 _dev_t: DeviceNumber, 1799 ) -> Result<Arc<dyn IndexNode>, SystemError> { 1800 let mut inode = self.0.lock(); 1801 if inode.metadata.file_type != FileType::Dir { 1802 return Err(SystemError::ENOTDIR); 1803 } 1804 1805 // 判断需要创建的类型 1806 if unlikely(mode.contains(ModeType::S_IFREG)) { 1807 // 普通文件 1808 return self.create(filename, FileType::File, mode); 1809 } 1810 1811 let dname = DName::from(filename); 1812 let nod = LockedFATInode::new( 1813 dname, 1814 inode.fs.upgrade().unwrap(), 1815 inode.self_ref.clone(), 1816 FATDirEntry::File(FATFile::default()), 1817 ); 1818 1819 if mode.contains(ModeType::S_IFIFO) { 1820 nod.0.lock().metadata.file_type = FileType::Pipe; 1821 // 创建pipe文件 1822 let pipe_inode = LockedPipeInode::new(); 1823 // 设置special_node 1824 nod.0.lock().special_node = Some(SpecialNodeData::Pipe(pipe_inode)); 1825 } else if mode.contains(ModeType::S_IFBLK) { 1826 nod.0.lock().metadata.file_type = FileType::BlockDevice; 1827 unimplemented!() 1828 } else if mode.contains(ModeType::S_IFCHR) { 1829 nod.0.lock().metadata.file_type = FileType::CharDevice; 1830 unimplemented!() 1831 } else { 1832 return Err(SystemError::EINVAL); 1833 } 1834 1835 inode.children.insert(to_search_name(filename), nod.clone()); 1836 Ok(nod) 1837 } 1838 special_node(&self) -> Option<SpecialNodeData>1839 fn special_node(&self) -> Option<SpecialNodeData> { 1840 self.0.lock().special_node.clone() 1841 } 1842 dname(&self) -> Result<DName, SystemError>1843 fn dname(&self) -> Result<DName, SystemError> { 1844 Ok(self.0.lock().dname.clone()) 1845 } 1846 parent(&self) -> Result<Arc<dyn IndexNode>, SystemError>1847 fn parent(&self) -> Result<Arc<dyn IndexNode>, SystemError> { 1848 self.0 1849 .lock() 1850 .parent 1851 .upgrade() 1852 .map(|item| item as Arc<dyn IndexNode>) 1853 .ok_or(SystemError::EINVAL) 1854 } 1855 page_cache(&self) -> Option<Arc<PageCache>>1856 fn page_cache(&self) -> Option<Arc<PageCache>> { 1857 self.0.lock().page_cache.clone() 1858 } 1859 } 1860 1861 impl Default for FATFsInfo { default() -> Self1862 fn default() -> Self { 1863 return FATFsInfo { 1864 lead_sig: FATFsInfo::LEAD_SIG, 1865 struc_sig: FATFsInfo::STRUC_SIG, 1866 free_count: 0xFFFFFFFF, 1867 next_free: RESERVED_CLUSTERS, 1868 trail_sig: FATFsInfo::TRAIL_SIG, 1869 dirty: false, 1870 offset: None, 1871 }; 1872 } 1873 } 1874 1875 impl Cluster { new(cluster: u64) -> Self1876 pub fn new(cluster: u64) -> Self { 1877 return Cluster { 1878 cluster_num: cluster, 1879 parent_cluster: 0, 1880 }; 1881 } 1882 } 1883 1884 /// @brief 用于迭代FAT表的内容的簇迭代器对象 1885 #[derive(Debug)] 1886 struct ClusterIter<'a> { 1887 /// 迭代器的next要返回的簇 1888 current_cluster: Option<Cluster>, 1889 /// 属于的文件系统 1890 fs: &'a FATFileSystem, 1891 } 1892 1893 impl Iterator for ClusterIter<'_> { 1894 type Item = Cluster; 1895 next(&mut self) -> Option<Self::Item>1896 fn next(&mut self) -> Option<Self::Item> { 1897 // 当前要返回的簇 1898 let ret: Option<Cluster> = self.current_cluster; 1899 1900 // 获得下一个要返回簇 1901 let new: Option<Cluster> = match self.current_cluster { 1902 Some(c) => { 1903 let entry: Option<FATEntry> = self.fs.get_fat_entry(c).ok(); 1904 match entry { 1905 Some(FATEntry::Next(c)) => Some(c), 1906 _ => None, 1907 } 1908 } 1909 _ => None, 1910 }; 1911 1912 self.current_cluster = new; 1913 return ret; 1914 } 1915 } 1916