diff options
| -rw-r--r-- | pathfs_frontend/file.go | 16 | ||||
| -rw-r--r-- | pathfs_frontend/file_holes.go | 38 |
2 files changed, 48 insertions, 6 deletions
diff --git a/pathfs_frontend/file.go b/pathfs_frontend/file.go index 9c58557..2c2f1eb 100644 --- a/pathfs_frontend/file.go +++ b/pathfs_frontend/file.go @@ -113,7 +113,7 @@ func (f *file) doRead(off uint64, length uint64) ([]byte, fuse.Status) { // Read - FUSE call func (f *file) Read(buf []byte, off int64) (resultData fuse.ReadResult, code fuse.Status) { - cryptfs.Debug.Printf("ino%d: Read: offset=%d length=%d\n", f.ino, len(buf), off) + cryptfs.Debug.Printf("ino%d: FUSE Read: offset=%d length=%d\n", f.ino, len(buf), off) if f.writeOnly { cryptfs.Warn.Printf("ino%d: Tried to read from write-only file\n", f.ino) @@ -133,10 +133,8 @@ func (f *file) Read(buf []byte, off int64) (resultData fuse.ReadResult, code fus return fuse.ReadResultData(out), status } -// Write - FUSE call -func (f *file) Write(data []byte, off int64) (uint32, fuse.Status) { - cryptfs.Debug.Printf("ino%d: Write %s: offset=%d length=%d\n", f.ino, off, len(data)) - +// Do the actual write +func (f *file) doWrite(data []byte, off int64) (uint32, fuse.Status) { var written uint32 status := fuse.OK dataBuf := bytes.NewBuffer(data) @@ -177,10 +175,16 @@ func (f *file) Write(data []byte, off int64) (uint32, fuse.Status) { } written += uint32(b.Length) } - return written, 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) + return f.doWrite(data, off) +} + // Release - FUSE call, forget file func (f *file) Release() { f.lock.Lock() diff --git a/pathfs_frontend/file_holes.go b/pathfs_frontend/file_holes.go new file mode 100644 index 0000000..8c9c83f --- /dev/null +++ b/pathfs_frontend/file_holes.go @@ -0,0 +1,38 @@ +package pathfs_frontend + +import ( + "fmt" + "github.com/hanwen/go-fuse/fuse" + "github.com/rfjakob/gocryptfs/cryptfs" +) + +// Will a write to offset "off" create a file hole? +func (f *file) createsHole(cipherSize uint64, off int64) bool { + nextBlock := f.cfs.BlockNoCipherOff(cipherSize) + targetBlock := f.cfs.BlockNoPlainOff(uint64(off)) + if targetBlock > nextBlock { + return true + } + return false +} + +// Zero-pad the file if a write to "off" creates a file hole +func (f *file) conditionalZeroPad(off int64) fuse.Status { + fi, err := f.fd.Stat() + if err != nil { + cryptfs.Warn.Printf("conditionalZeroPad: Stat: %v\n", err) + return fuse.ToStatus(err) + } + cipherSize := uint64(fi.Size()) + + if f.createsHole(cipherSize, off) == false { + return fuse.OK + } + + plainSize := f.cfs.PlainSize(cipherSize) + lastBlockLen := plainSize % f.cfs.PlainBS() + missing := f.cfs.PlainBS() - lastBlockLen + pad := make([]byte, missing) + _, status := f.doWrite(pad, int64(plainSize)) + return status +} |