* * @param: 文件描述符传来的InstanceSeq;要删除的文件的名字 * @return: 成功删除返回true，否则返回false * @notes: 需要检测name是否存在; 调用方先判断bool再看seq */
(InstanceSeq uint64, filename string, locktype int, checksum uint64)
| 298 | * @notes: 需要检测name是否存在; 调用方先判断bool再看seq |
| 299 | */ |
| 300 | func (Fsn *FileSystemNode) Acquire(InstanceSeq uint64, filename string, locktype int, checksum uint64) (uint64, error) { |
| 301 | Node, IsExist := Fsn.next[filename] |
| 302 | |
| 303 | if !IsExist { |
| 304 | log.Printf("INFO : %s/%s does not exist.\n", Fsn.nowPath, filename) |
| 305 | return 0, ChubbyGoFileSystemError(PathError) |
| 306 | } |
| 307 | |
| 308 | if checksum != Node.checksum { |
| 309 | log.Printf("WARNING : A danger requirment, unmatched checksum, now(%d) -> client(%d).\n", checksum, Node.checksum) |
| 310 | return 0, ChubbyGoFileSystemError(CheckSumError) |
| 311 | } |
| 312 | |
| 313 | if InstanceSeq < Node.instanceSeq { |
| 314 | log.Println("WARNING : Acquire -> Request from a backward file descriptor!") |
| 315 | return 0, ChubbyGoFileSystemError(InstanceSeqError) |
| 316 | } |
| 317 | |
| 318 | if Node.nowLockType == NotLock { |
| 319 | if locktype == ReadLock { |
| 320 | Node.readLockReferenceCount++ |
| 321 | } |
| 322 | Node.nowLockType = locktype |
| 323 | } else if Node.nowLockType == ReadLock && locktype == ReadLock { |
| 324 | Node.readLockReferenceCount++ |
| 325 | return Node.tokenSeq, nil |
| 326 | } else if Node.nowLockType == WriteLock { // 和下面分开写是为了清楚的看到所有情况 |
| 327 | return 0, ChubbyGoFileSystemError(LockTypeError) |
| 328 | } else { // now readLock, args writelock |
| 329 | return 0, ChubbyGoFileSystemError(LockTypeError) |
| 330 | } |
| 331 | |
| 332 | return Node.tokenSeq, nil // 直接返回当前值，在release的时候加1就可以了 |
| 333 | } |
| 334 | |
| 335 | /* |
| 336 | * @param: 文件描述符传来的InstanceSeq;要释放的文件(锁)的名字 |
nothing calls this directly
no test coverage detected