compare checksums on upload/download via FUSE

cmd/mount/mount.go

@@ -22,6 +22,7 @@ import (
 // Globals
 var (
 	noModTime    = false
+	noChecksum   = false
 	debugFUSE    = false
 	noSeek       = false
 	dirCacheTime = 5 * 60 * time.Second
@@ -47,6 +48,7 @@ func init() {
 	unix.Umask(umask)     // set it back to what it was
 	cmd.Root.AddCommand(commandDefintion)
 	commandDefintion.Flags().BoolVarP(&noModTime, "no-modtime", "", noModTime, "Don't read/write the modification time (can speed things up).")
+	commandDefintion.Flags().BoolVarP(&noChecksum, "no-checksum", "", noChecksum, "Don't compare checksums on up/download.")
 	commandDefintion.Flags().BoolVarP(&debugFUSE, "debug-fuse", "", debugFUSE, "Debug the FUSE internals - needs -v.")
 	commandDefintion.Flags().BoolVarP(&noSeek, "no-seek", "", noSeek, "Don't allow seeking in files.")
 	commandDefintion.Flags().DurationVarP(&dirCacheTime, "dir-cache-time", "", dirCacheTime, "Time to cache directory entries for.")
@@ -126,10 +128,6 @@ files to be visible in the mount.
     * those which need to know the size in advance won't - eg B2
     * maybe should pass in size as -1 to mean work it out
     * Or put in an an upload cache to cache the files on disk first
-
-### TODO ###
-
-  * Check hashes on upload/download
 `,
 	Run: func(command *cobra.Command, args []string) {
 		cmd.CheckArgs(2, 2, command, args)

cmd/mount/read.go

@@ -9,6 +9,7 @@ import (
 	"bazil.org/fuse"
 	fusefs "bazil.org/fuse/fs"
 	"github.com/ncw/rclone/fs"
+	"github.com/pkg/errors"
 	"golang.org/x/net/context"
 )
 
@@ -20,6 +21,7 @@ type ReadFileHandle struct {
 	o          fs.Object
 	readCalled bool // set if read has been called
 	offset     int64
+	hash       *fs.MultiHasher
 }
 
 func newReadFileHandle(o fs.Object) (*ReadFileHandle, error) {
@@ -27,9 +29,19 @@ func newReadFileHandle(o fs.Object) (*ReadFileHandle, error) {
 	if err != nil {
 		return nil, err
 	}
+
+	var hash *fs.MultiHasher
+	if !noChecksum {
+		hash, err = fs.NewMultiHasherTypes(o.Fs().Hashes())
+		if err != nil {
+			fs.Errorf(o.Fs(), "newReadFileHandle hash error: %v", err)
+		}
+	}
+
 	fh := &ReadFileHandle{
 		o:    o,
 		r:    fs.NewAccount(r, o).WithBuffer(), // account the transfer
+		hash: hash,
 	}
 	fs.Stats.Transferring(fh.o.Remote())
 	return fh, nil
@@ -48,6 +60,7 @@ var _ fusefs.HandleReader = (*ReadFileHandle)(nil)
 // Must be called with fh.mu held
 func (fh *ReadFileHandle) seek(offset int64, reopen bool) (err error) {
 	fh.r.StopBuffering() // stop the background reading first
+	fh.hash = nil
 	oldReader := fh.r.GetReader()
 	r := oldReader
 	// Can we seek it directly?
@@ -141,6 +154,14 @@ func (fh *ReadFileHandle) Read(ctx context.Context, req *fuse.ReadRequest, resp
 		resp.Data = buf[:n]
 		fh.offset = newOffset
 		fs.Debugf(fh.o, "ReadFileHandle.Read OK")
+
+		if fh.hash != nil {
+			_, err = fh.hash.Write(resp.Data)
+			if err != nil {
+				fs.Errorf(fh.o, "ReadFileHandle.Read HashError: %v", err)
+				return err
+			}
+		}
 	}
 	return err
 }
@@ -155,12 +176,35 @@ func (fh *ReadFileHandle) close() error {
 	}
 	fh.closed = true
 	fs.Stats.DoneTransferring(fh.o.Remote(), true)
+
+	if err := fh.checkHash(); err != nil {
+		return err
+	}
+
 	return fh.r.Close()
 }
 
 // Check interface satisfied
 var _ fusefs.HandleFlusher = (*ReadFileHandle)(nil)
 
+func (fh *ReadFileHandle) checkHash() error {
+	if fh.hash == nil || !fh.readCalled || fh.offset < fh.o.Size() {
+		return nil
+	}
+
+	for hashType, dstSum := range fh.hash.Sums() {
+		srcSum, err := fh.o.Hash(hashType)
+		if err != nil {
+			return err
+		}
+		if !fs.HashEquals(dstSum, srcSum) {
+			return errors.Errorf("corrupted on transfer: %v hash differ %q vs %q", hashType, dstSum, srcSum)
+		}
+	}
+
+	return nil
+}
+
 // Flush is called each time the file or directory is closed.
 // Because there can be multiple file descriptors referring to a
 // single opened file, Flush can be called multiple times.
@@ -169,23 +213,11 @@ func (fh *ReadFileHandle) Flush(ctx context.Context, req *fuse.FlushRequest) err
 	defer fh.mu.Unlock()
 	fs.Debugf(fh.o, "ReadFileHandle.Flush")
 
-	// Ignore the Flush as there is nothing we can sensibly do and
-	// it seems quite common for Flush to be called from
-	// different threads each of which have read some data.
-	if false {
-		// If Read hasn't been called then ignore the Flush - Release
-		// will pick it up
-		if !fh.readCalled {
-			fs.Debugf(fh.o, "ReadFileHandle.Flush ignoring flush on unread handle")
-			return nil
-
-		}
-		err := fh.close()
-		if err != nil {
+	if err := fh.checkHash(); err != nil {
 		fs.Errorf(fh.o, "ReadFileHandle.Flush error: %v", err)
 		return err
 	}
-	}
+
 	fs.Debugf(fh.o, "ReadFileHandle.Flush OK")
 	return nil
 }

cmd/mount/read_test.go

@@ -37,6 +37,45 @@ func TestReadByByte(t *testing.T) {
 	run.rm(t, "testfile")
 }
 
+func TestReadChecksum(t *testing.T) {
+	run.skipIfNoFUSE(t)
+
+	// create file big enough so we exceed any single FUSE read
+	// request
+	b := make([]rune, 3*128*1024)
+	for i := range b {
+		b[i] = 'r'
+	}
+	run.createFile(t, "bigfile", string(b))
+
+	// The hash comparison would fail in Flush, if we did not
+	// ensure we read the whole file
+	fd, err := os.Open(run.path("bigfile"))
+	assert.NoError(t, err)
+	buf := make([]byte, 10)
+	_, err = io.ReadFull(fd, buf)
+	assert.NoError(t, err)
+	err = fd.Close()
+	assert.NoError(t, err)
+
+	// The hash comparison would fail, because we only read parts
+	// of the file
+	fd, err = os.Open(run.path("bigfile"))
+	assert.NoError(t, err)
+	// read at start
+	_, err = io.ReadFull(fd, buf)
+	assert.NoError(t, err)
+	// read at end
+	_, err = fd.Seek(int64(len(b)-len(buf)), 0)
+	assert.NoError(t, err)
+	_, err = io.ReadFull(fd, buf)
+	// ensure we don't compare hashes
+	err = fd.Close()
+	assert.NoError(t, err)
+
+	run.rm(t, "bigfile")
+}
+
 // Test double close
 func TestReadFileDoubleClose(t *testing.T) {
 	run.skipIfNoFUSE(t)

cmd/mount/write.go

@@ -3,13 +3,13 @@
 package mount
 
 import (
-	"errors"
 	"io"
 	"sync"
 
 	"bazil.org/fuse"
 	fusefs "bazil.org/fuse/fs"
 	"github.com/ncw/rclone/fs"
+	"github.com/pkg/errors"
 	"golang.org/x/net/context"
 )
 
@@ -26,17 +26,29 @@ type WriteFileHandle struct {
 	result      chan error
 	file        *File
 	writeCalled bool // set the first time Write() is called
+	hash        *fs.MultiHasher
 }
 
 // Check interface satisfied
 var _ fusefs.Handle = (*WriteFileHandle)(nil)
 
 func newWriteFileHandle(d *Dir, f *File, src fs.ObjectInfo) (*WriteFileHandle, error) {
+	var hash *fs.MultiHasher
+	if !noChecksum {
+		var err error
+		hash, err = fs.NewMultiHasherTypes(src.Fs().Hashes())
+		if err != nil {
+			fs.Errorf(src.Fs(), "newWriteFileHandle hash error: %v", err)
+		}
+	}
+
 	fh := &WriteFileHandle{
 		remote: src.Remote(),
 		result: make(chan error, 1),
 		file:   f,
+		hash:   hash,
 	}
+
 	fh.pipeReader, fh.pipeWriter = io.Pipe()
 	r := fs.NewAccountSizeName(fh.pipeReader, 0, src.Remote()).WithBuffer() // account the transfer
 	go func() {
@@ -71,6 +83,13 @@ func (fh *WriteFileHandle) Write(ctx context.Context, req *fuse.WriteRequest, re
 		return err
 	}
 	fs.Debugf(fh.remote, "WriteFileHandle.Write OK (%d bytes written)", n)
+	if fh.hash != nil {
+		_, err = fh.hash.Write(req.Data)
+		if err != nil {
+			fs.Errorf(fh.remote, "WriteFileHandle.Write HashError: %v", err)
+			return err
+		}
+	}
 	return nil
 }
 
@@ -95,6 +114,17 @@ func (fh *WriteFileHandle) close() error {
 	if err == nil {
 		err = readCloseErr
 	}
+	if err == nil && fh.hash != nil {
+		for hashType, srcSum := range fh.hash.Sums() {
+			dstSum, err := fh.o.Hash(hashType)
+			if err != nil {
+				return err
+			}
+			if !fs.HashEquals(srcSum, dstSum) {
+				return errors.Errorf("corrupted on transfer: %v hash differ %q vs %q", hashType, srcSum, dstSum)
+			}
+		}
+	}
 	return err
 }