allow concurrent access, check fInfo for nil

readnetfs.go

@@ -7,30 +7,32 @@ import (
  "github.com/hanwen/go-fuse/v2/fuse"
  "github.com/rs/zerolog"
  "github.com/rs/zerolog/log"
+ "golang.org/x/sync/semaphore"
  "os"
  "readnetfs/cache"
  "readnetfs/fileretriever"
  "strings"
- "sync"
  "syscall"
 )
 
+var MAX_CONCURRENCY int64 = 10
+
 type VirtNode struct {
  fusefs.Inode
  path fileretriever.RemotePath
- mu sync.Mutex
+ sem *semaphore.Weighted
  fc *fileretriever.FileClient
 }
 
 func (n *VirtNode) Open(ctx context.Context, openFlags uint32) (fh fusefs.FileHandle, fuseFlags uint32, errno syscall.Errno) {
- n.mu.Lock()
- defer n.mu.Unlock()
+ n.sem.Acquire(ctx, 1)
+ defer n.sem.Release(1)
  return nil, 0, 0
 }
 
 func (n *VirtNode) Read(ctx context.Context, fh fusefs.FileHandle, dest []byte, off int64) (fuse.ReadResult, syscall.Errno) {
- n.mu.Lock()
- defer n.mu.Unlock()
+ n.sem.Acquire(ctx, 1)
+ defer n.sem.Release(1)
  log.Trace().Msgf("Reading at %d from %s", off, n.path)
  cacheEntry := n.fc.GetCachedFile(n.path)
  if cacheEntry != nil {
@@ -68,14 +70,14 @@ func (n *VirtNode) Read(ctx context.Context, fh fusefs.FileHandle, dest []byte,
 }
 
 func (n *VirtNode) Write(ctx context.Context, fh fusefs.FileHandle, buf []byte, off int64) (uint32, syscall.Errno) {
- n.mu.Lock()
- defer n.mu.Unlock()
+ n.sem.Acquire(ctx, 1)
+ defer n.sem.Release(1)
  return 0, 0
 }
 
 func (n *VirtNode) Getattr(ctx context.Context, fh fusefs.FileHandle, out *fuse.AttrOut) syscall.Errno {
- n.mu.Lock()
- defer n.mu.Unlock()
+ n.sem.Acquire(ctx, 1)
+ defer n.sem.Release(1)
  fInfo, err := n.fc.FileInfo(n.path)
  if err != nil {
  return syscall.EIO
@@ -86,12 +88,13 @@ func (n *VirtNode) Getattr(ctx context.Context, fh fusefs.FileHandle, out *fuse.
 }
 
 func (n *VirtNode) Lookup(ctx context.Context, name string, out *fuse.EntryOut) (*fusefs.Inode, syscall.Errno) {
- n.mu.Lock()
- defer n.mu.Unlock()
+ n.sem.Acquire(ctx, 1)
+ defer n.sem.Release(1)
  log.Debug().Msgf("Looking up %s in %s", name, n.path)
  childpath := n.path.Append(name)
  fInfo, err := n.fc.FileInfo(childpath)
- if err != nil {
+ //TODO proper fix of nil finfo
+ if err != nil || fInfo == nil {
  log.Debug().Err(err).Msgf("Failed to read file info for %s", childpath)
  return nil, syscall.EIO
  }
@@ -104,6 +107,7 @@ func (n *VirtNode) Lookup(ctx context.Context, name string, out *fuse.EntryOut)
  stable.Mode = uint32(fuse.S_IFREG)
  }
  cNode := &VirtNode{
+ sem: semaphore.NewWeighted(MAX_CONCURRENCY),
  path: childpath,
  fc: n.fc,
  }
@@ -112,8 +116,8 @@ func (n *VirtNode) Lookup(ctx context.Context, name string, out *fuse.EntryOut)
 }
 
 func (n *VirtNode) Readdir(ctx context.Context) (fusefs.DirStream, syscall.Errno) {
- n.mu.Lock()
- defer n.mu.Unlock()
+ n.sem.Acquire(ctx, 1)
+ defer n.sem.Release(1)
  log.Trace().Msgf("Reading dir %s", n.path)
  entries, err := n.fc.ReadDir(n.path)
  if err != nil {
@@ -166,6 +170,7 @@ func main() {
  os.Mkdir(*mntDir, 0755)
  root := &VirtNode{
  Inode: fusefs.Inode{},
+ sem: semaphore.NewWeighted(MAX_CONCURRENCY),
  path: "",
  fc: fclient,
  }