fusego/samples/readbenchfs/readbenchfs.go

168 lines
3.9 KiB
Go

// Copyright 2021 Vitaliy Filippov
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package readbenchfs
import (
"golang.org/x/net/context"
"io"
"math/rand"
"os"
"github.com/jacobsa/fuse"
"github.com/jacobsa/fuse/fuseops"
"github.com/jacobsa/fuse/fuseutil"
)
type readBenchFS struct {
fuseutil.NotImplementedFileSystem
buf []byte
}
// 1 TB
const fileSize = 1024 * 1024 * 1024 * 1024
var _ fuseutil.FileSystem = &readBenchFS{}
// Create a file system that mirrors an existing physical path, in a readonly mode
func NewReadBenchServer() (server fuse.Server, err error) {
// 1 GB of random data to exceed CPU cache
buf := make([]byte, 1024*1024*1024)
rand.Read(buf)
server = fuseutil.NewFileSystemServer(&readBenchFS{
buf: buf,
})
return
}
func (fs *readBenchFS) StatFS(ctx context.Context, op *fuseops.StatFSOp) error {
return nil
}
func (fs *readBenchFS) LookUpInode(ctx context.Context, op *fuseops.LookUpInodeOp) error {
if op.Name == "test" {
op.Entry = fuseops.ChildInodeEntry{
Child: 2,
Attributes: fuseops.InodeAttributes{
Size: fileSize,
Nlink: 1,
Mode: 0444,
},
}
return nil
}
return fuse.ENOENT
}
func (fs *readBenchFS) GetInodeAttributes(ctx context.Context, op *fuseops.GetInodeAttributesOp) error {
if op.Inode == 1 {
op.Attributes = fuseops.InodeAttributes{
Nlink: 1,
Mode: 0755 | os.ModeDir,
}
return nil
} else if op.Inode == 2 {
op.Attributes = fuseops.InodeAttributes{
Size: fileSize,
Nlink: 1,
Mode: 0444,
}
return nil
}
return fuse.ENOENT
}
func (fs *readBenchFS) OpenDir(ctx context.Context, op *fuseops.OpenDirOp) error {
// Allow opening any directory.
return nil
}
func (fs *readBenchFS) ReadDir(ctx context.Context, op *fuseops.ReadDirOp) error {
if op.Inode != 1 {
return fuse.ENOENT
}
if op.Offset > 0 {
return nil
}
entries := []fuseutil.Dirent{
fuseutil.Dirent{
Offset: 1,
Inode: 2,
Name: "test",
Type: fuseutil.DT_File,
},
}
for _, e := range entries[op.Offset:] {
n := fuseutil.WriteDirent(op.Dst[op.BytesRead:], e)
if n == 0 {
break
}
op.BytesRead += n
}
return nil
}
func (fs *readBenchFS) OpenFile(ctx context.Context, op *fuseops.OpenFileOp) error {
// Allow opening any file.
return nil
}
func (fs *readBenchFS) ReadFile(ctx context.Context, op *fuseops.ReadFileOp) error {
if op.Offset > fileSize {
return io.EOF
}
end := op.Offset + int64(len(op.Dst))
if end > fileSize {
end = fileSize
}
buflen := int64(len(fs.buf))
for pos := op.Offset; pos < end; {
s := pos % buflen
e := buflen
if e-s > end-pos {
e = s + end - pos
}
copy(op.Dst[pos-op.Offset:], fs.buf[s:])
pos = op.Offset + e
}
//op.Data = [][]byte{ contents[op.Offset : end] }
op.BytesRead = int(end - op.Offset)
return nil
}
func (fs *readBenchFS) ReleaseDirHandle(ctx context.Context, op *fuseops.ReleaseDirHandleOp) error {
return nil
}
func (fs *readBenchFS) GetXattr(ctx context.Context, op *fuseops.GetXattrOp) error {
return nil
}
func (fs *readBenchFS) ListXattr(ctx context.Context, op *fuseops.ListXattrOp) error {
return nil
}
func (fs *readBenchFS) ForgetInode(ctx context.Context, op *fuseops.ForgetInodeOp) error {
return nil
}
func (fs *readBenchFS) ReleaseFileHandle(ctx context.Context, op *fuseops.ReleaseFileHandleOp) error {
return nil
}
func (fs *readBenchFS) FlushFile(ctx context.Context, op *fuseops.FlushFileOp) error {
return nil
}