forked from janelia-flyem/dvid
/
fuse.go
163 lines (142 loc) · 4.25 KB
/
fuse.go
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/*
This file supports a FUSE file system implementation for keyvalue data.
*/
package keyvalue
import (
"fmt"
"os"
"bazil.org/fuse"
"bazil.org/fuse/fs"
"github.com/janelia-flyem/dvid/datastore"
"github.com/janelia-flyem/dvid/dvid"
"github.com/janelia-flyem/dvid/server"
"github.com/janelia-flyem/dvid/storage"
)
// Mount creates (if not already present) a FUSE file system for this data.
func (d *Data) Mount(request datastore.Request, reply *datastore.Response) error {
var uuidStr, dataName, cmdStr string
dirnames := request.CommandArgs(1, &uuidStr, &dataName, &cmdStr)
if len(dirnames) > 1 || len(dirnames) == 0 {
return fmt.Errorf("Please specify a single directory to be mounted.\n")
}
// Make sure we have a directory for this particular UUID.
uuid, datasetID, versionID, err := server.DatastoreService().NodeIDFromString(uuidStr)
if err != nil {
return err
}
// Make sure we have a FUSE file system at mount directory.
versionInfo := storage.NewVersionInfo(uuid, datasetID, versionID)
err = storage.OpenFUSE(dirnames[0], d, versionInfo)
if err != nil {
return err
}
reply.Output = []byte(fmt.Sprintf("Using FUSE file system for UUID %s, data %s @ mount %s\n",
uuid, d.DataName(), dirnames[0]))
return nil
}
// ---- storage.Mountable interface implementation
func (d *Data) FUSEDir(vinfo storage.VersionInfo) storage.FUSEDirer {
return Dir{d, vinfo}
}
// Dir implements both Node and Handle for this data directory
// Each directory is specific to one data in a dataset.
type Dir struct {
*Data
storage.VersionInfo
}
func (d Dir) Attr() fuse.Attr {
return fuse.Attr{
Inode: storage.GenerateInode(d.Data.LocalID(), d.GetVersionID(), nil),
Mode: os.ModeDir | 0555,
}
}
func (d Dir) Lookup(name string, intr fs.Intr) (fs.Node, fuse.Error) {
return File{&d, name}, nil
}
// ReadDir returns a list of keys available for this data and its version.
func (d Dir) ReadDir(intr fs.Intr) ([]fuse.Dirent, fuse.Error) {
minDataKey := &datastore.DataKey{d.Data.DsetID, d.Data.ID, d.GetVersionID(), dvid.IndexString("")}
maxDataKey := &datastore.DataKey{d.Data.DsetID, d.Data.ID, d.GetVersionID() + 1, dvid.IndexString("")}
db, err := server.OrderedKeyValueGetter()
if err != nil {
return nil, fuse.EIO
}
keys, err := db.KeysInRange(minDataKey, maxDataKey)
if err != nil {
return nil, fuse.EIO
}
ddirs := []fuse.Dirent{}
for _, key := range keys {
dataKey, ok := key.(*datastore.DataKey)
if ok {
entry := fuse.Dirent{
Inode: storage.GenerateInode(d.Data.LocalID(), d.GetVersionID(), dataKey.Index),
Name: dataKey.Index.String(),
Type: fuse.DT_File,
}
ddirs = append(ddirs, entry)
}
}
return ddirs, nil
}
func (d Dir) Write(req *fuse.WriteRequest, resp *fuse.WriteResponse, intr fs.Intr) fuse.Error {
fmt.Printf("Unsupported Dir Write: %s\n", req.String())
return fuse.EIO
}
// File implements both Node and Handle for a keyvalue entry.
type File struct {
*Dir
keyStr string
}
func (f File) Attr() fuse.Attr {
return fuse.Attr{Mode: 0444}
}
func (f File) Read(req *fuse.ReadRequest, resp *fuse.ReadResponse, intr fs.Intr) fuse.Error {
fmt.Printf("Reading key %s at offset %d\n", f.keyStr, req.Offset)
data, found, err := f.Dir.Data.GetData(f.Dir.GetUUID(), f.keyStr)
if err != nil {
return fuse.EIO
}
if !found {
return fuse.ENOENT
}
resp.Data = data
return nil
}
func (f File) ReadAll(intr fs.Intr) ([]byte, fuse.Error) {
fmt.Printf("Reading all for key %s\n", f.keyStr)
data, found, err := f.Dir.Data.GetData(f.Dir.GetUUID(), f.keyStr)
if err != nil {
return nil, fuse.EIO
}
if !found {
return nil, fuse.ENOENT
}
return data, nil
}
// Append data
func (f File) Write(req *fuse.WriteRequest, resp *fuse.WriteResponse, intr fs.Intr) fuse.Error {
fmt.Printf("Write of %d bytes at offset %d\n", len(req.Data), req.Offset)
data, found, err := f.Dir.Data.GetData(f.Dir.GetUUID(), f.keyStr)
if err != nil {
return fuse.EIO
}
if !found {
return fuse.ENOENT
}
if data == nil {
data = []byte{}
}
data = append(data, req.Data...)
err = f.Dir.Data.PutData(f.Dir.GetUUID(), f.keyStr, data)
resp.Size = len(req.Data)
return nil
}
// Replace data
func (f File) WriteAll(b []byte, intr fs.Intr) fuse.Error {
err := f.Dir.Data.PutData(f.Dir.GetUUID(), f.keyStr, b)
if err != nil {
return fuse.EIO
}
return nil
}