diff options
Diffstat (limited to 'pathfs_frontend/file.go')
| -rw-r--r-- | pathfs_frontend/file.go | 124 |
1 files changed, 55 insertions, 69 deletions
diff --git a/pathfs_frontend/file.go b/pathfs_frontend/file.go index 2c2f1eb..733bfd0 100644 --- a/pathfs_frontend/file.go +++ b/pathfs_frontend/file.go @@ -181,7 +181,20 @@ func (f *file) doWrite(data []byte, off int64) (uint32, fuse.Status) { // Write - FUSE call func (f *file) Write(data []byte, off int64) (uint32, fuse.Status) { cryptfs.Debug.Printf("ino%d: FUSE Write %s: offset=%d length=%d\n", f.ino, off, len(data)) - f.conditionalZeroPad(off) + + fi, err := f.fd.Stat() + if err != nil { + cryptfs.Warn.Printf("Write: Fstat failed: %v\n", err) + return 0, fuse.ToStatus(err) + } + plainSize := f.cfs.PlainSize(uint64(fi.Size())) + if f.createsHole(plainSize, off) { + status := f.zeroPad(plainSize) + if status != fuse.OK { + cryptfs.Warn.Printf("zeroPad returned error %v\n", status) + return 0, status + } + } return f.doWrite(data, off) } @@ -219,19 +232,11 @@ func (f *file) Fsync(flags int) (code fuse.Status) { func (f *file) Truncate(newSize uint64) fuse.Status { - // Common case: Truncate to zero - if newSize == 0 { - f.lock.Lock() - err := syscall.Ftruncate(int(f.fd.Fd()), 0) - f.lock.Unlock() - return fuse.ToStatus(err) - } - // We need the old file size to determine if we are growing or shrinking // the file fi, err := f.fd.Stat() if err != nil { - cryptfs.Warn.Printf("Truncate: fstat failed: %v\n", err) + cryptfs.Warn.Printf("Truncate: Fstat failed: %v\n", err) return fuse.ToStatus(err) } oldSize := f.cfs.PlainSize(uint64(fi.Size())) @@ -240,77 +245,58 @@ func (f *file) Truncate(newSize uint64) fuse.Status { newB := (newSize + f.cfs.PlainBS() - 1) / f.cfs.PlainBS() cryptfs.Debug.Printf("ino%d: truncate from %d to %d blocks (%d to %d bytes)\n", f.ino, oldB, newB, oldSize, newSize) } - // Grow file by appending zeros + + // File grows if newSize > oldSize { - remaining := newSize - oldSize - offset := oldSize - var zeros []byte - // Append a maximum of 1MB in each iteration - if remaining > 1048576 { - zeros = make([]byte, 1048576) - } else { - zeros = make([]byte, remaining) + blocks := f.cfs.SplitRange(oldSize, newSize - oldSize) + for _, b := range(blocks) { + // First and last block may be partial + if b.IsPartial() { + off, _ := b.PlaintextRange() + off += b.Offset + _, status := f.doWrite(make([]byte, b.Length), int64(off)) + if status != fuse.OK { + return status + } + } else { + off, length := b.CiphertextRange() + f.lock.Lock() + err := syscall.Ftruncate(int(f.fd.Fd()), int64(off + length)) + f.lock.Unlock() + if err != nil { + cryptfs.Warn.Printf("grow Ftruncate returned error: %v", err) + return fuse.ToStatus(err) + } + } } - for remaining >= uint64(len(zeros)) { - written, status := f.Write(zeros, int64(offset)) + return fuse.OK + // File shrinks + } else { + blockNo := f.cfs.BlockNoPlainOff(newSize) + lastBlockOff := blockNo * f.cfs.PlainBS() + lastBlockLen := newSize - lastBlockOff + var data []byte + if lastBlockLen > 0 { + var status fuse.Status + data, status = f.doRead(lastBlockOff, lastBlockLen) if status != fuse.OK { + cryptfs.Warn.Printf("shrink doRead returned error: %v", err) return status } - remaining -= uint64(written) - offset += uint64(written) - cryptfs.Debug.Printf("Truncate: written=%d remaining=%d offset=%d\n", - written, remaining, offset) - } - if remaining > 0 { - _, status := f.Write(zeros[0:remaining], int64(offset)) - return status } - return fuse.OK - } - // else: - // Shrink file by truncating - newBlockLen := int(newSize % f.cfs.PlainBS()) - // New file size is aligned to block size - just truncate - if newBlockLen == 0 { - cSize := int64(f.cfs.CipherSize(newSize)) - f.lock.Lock() - err := syscall.Ftruncate(int(f.fd.Fd()), cSize) - f.lock.Unlock() - return fuse.ToStatus(err) - } - // New file size is not aligned - need to do RMW on the last block - cryptfs.Debug.Printf("Truncate: Shrink RMW\n") - var blockOffset, blockLen uint64 - { - // Get the block the last byte belongs to. - // This is, by definition, the last block. - blockList := f.cfs.SplitRange(newSize - 1, 1) - lastBlock := blockList[0] - blockOffset, blockLen = lastBlock.PlaintextRange() - } - blockData, status := f.doRead(blockOffset, blockLen) - if status != fuse.OK { - cryptfs.Warn.Printf("Truncate: doRead failed: %v\n", err) - return status - } - if len(blockData) < newBlockLen { - cryptfs.Warn.Printf("Truncate: file has shrunk under our feet\n") - return fuse.OK - } - // Truncate the file down to the next block - { - nextBlockSz := int64(f.cfs.CipherSize(newSize - uint64(newBlockLen))) f.lock.Lock() - err = syscall.Ftruncate(int(f.fd.Fd()), nextBlockSz) + err = syscall.Ftruncate(int(f.fd.Fd()), int64(lastBlockOff)) f.lock.Unlock() if err != nil { - cryptfs.Warn.Printf("Truncate: Intermediate Ftruncate failed: %v\n", err) + cryptfs.Warn.Printf("shrink Ftruncate returned error: %v", err) return fuse.ToStatus(err) } + if lastBlockLen > 0 { + _, status := f.doWrite(data, int64(lastBlockOff)) + return status + } + return fuse.OK } - // Append truncated last block - _, status = f.Write(blockData[0:newBlockLen], int64(blockOffset)) - return status } func (f *file) Chmod(mode uint32) fuse.Status { |