rclone/cmd/mount/file.go
Nick Craig-Wood 0baafb158f mount: allow files of unkown size to be read properly
Before this change, files of unknown size (eg Google Docs) would
appear in file listings with 0 size and would only allow 0 bytes to be
read.

This change sets the direct_io flag in the FUSE return which bypasses
the cache for these files.  This means that they can be read properly.

This is compatible with some, but not all applications.
2019-09-14 13:22:33 +01:00

128 lines
3.5 KiB
Go

// +build linux darwin freebsd
package mount
import (
"context"
"time"
"bazil.org/fuse"
fusefs "bazil.org/fuse/fs"
"github.com/rclone/rclone/cmd/mountlib"
"github.com/rclone/rclone/fs/log"
"github.com/rclone/rclone/vfs"
)
// File represents a file
type File struct {
*vfs.File
}
// Check interface satisfied
var _ fusefs.Node = (*File)(nil)
// Attr fills out the attributes for the file
func (f *File) Attr(ctx context.Context, a *fuse.Attr) (err error) {
defer log.Trace(f, "")("a=%+v, err=%v", a, &err)
a.Valid = mountlib.AttrTimeout
modTime := f.File.ModTime()
Size := uint64(f.File.Size())
Blocks := (Size + 511) / 512
a.Gid = f.VFS().Opt.GID
a.Uid = f.VFS().Opt.UID
a.Mode = f.VFS().Opt.FilePerms
a.Size = Size
a.Atime = modTime
a.Mtime = modTime
a.Ctime = modTime
a.Crtime = modTime
a.Blocks = Blocks
return nil
}
// Check interface satisfied
var _ fusefs.NodeSetattrer = (*File)(nil)
// Setattr handles attribute changes from FUSE. Currently supports ModTime and Size only
func (f *File) Setattr(ctx context.Context, req *fuse.SetattrRequest, resp *fuse.SetattrResponse) (err error) {
defer log.Trace(f, "a=%+v", req)("err=%v", &err)
if !f.VFS().Opt.NoModTime {
if req.Valid.Mtime() {
err = f.File.SetModTime(req.Mtime)
} else if req.Valid.MtimeNow() {
err = f.File.SetModTime(time.Now())
}
}
if req.Valid.Size() {
err = f.File.Truncate(int64(req.Size))
}
return translateError(err)
}
// Check interface satisfied
var _ fusefs.NodeOpener = (*File)(nil)
// Open the file for read or write
func (f *File) Open(ctx context.Context, req *fuse.OpenRequest, resp *fuse.OpenResponse) (fh fusefs.Handle, err error) {
defer log.Trace(f, "flags=%v", req.Flags)("fh=%v, err=%v", &fh, &err)
// fuse flags are based off syscall flags as are os flags, so
// should be compatible
handle, err := f.File.Open(int(req.Flags))
if err != nil {
return nil, translateError(err)
}
// If size unknown then use direct io to read
if handle.Node().DirEntry().Size() < 0 {
resp.Flags |= fuse.OpenDirectIO
}
return &FileHandle{handle}, nil
}
// Check interface satisfied
var _ fusefs.NodeFsyncer = (*File)(nil)
// Fsync the file
//
// Note that we don't do anything except return OK
func (f *File) Fsync(ctx context.Context, req *fuse.FsyncRequest) (err error) {
defer log.Trace(f, "")("err=%v", &err)
return nil
}
// Getxattr gets an extended attribute by the given name from the
// node.
//
// If there is no xattr by that name, returns fuse.ErrNoXattr.
func (f *File) Getxattr(ctx context.Context, req *fuse.GetxattrRequest, resp *fuse.GetxattrResponse) error {
return fuse.ENOSYS // we never implement this
}
var _ fusefs.NodeGetxattrer = (*File)(nil)
// Listxattr lists the extended attributes recorded for the node.
func (f *File) Listxattr(ctx context.Context, req *fuse.ListxattrRequest, resp *fuse.ListxattrResponse) error {
return fuse.ENOSYS // we never implement this
}
var _ fusefs.NodeListxattrer = (*File)(nil)
// Setxattr sets an extended attribute with the given name and
// value for the node.
func (f *File) Setxattr(ctx context.Context, req *fuse.SetxattrRequest) error {
return fuse.ENOSYS // we never implement this
}
var _ fusefs.NodeSetxattrer = (*File)(nil)
// Removexattr removes an extended attribute for the name.
//
// If there is no xattr by that name, returns fuse.ErrNoXattr.
func (f *File) Removexattr(ctx context.Context, req *fuse.RemovexattrRequest) error {
return fuse.ENOSYS // we never implement this
}
var _ fusefs.NodeRemovexattrer = (*File)(nil)