X-Git-Url: https://git.arvados.org/arvados.git/blobdiff_plain/44ddbde1cd9945778ed7e4ae1d96c65e24f17742..a9be3117466506dffc39617be1c58406c5914e4b:/lib/mount/fs.go

diff --git a/lib/mount/fs.go b/lib/mount/fs.go
index 774948f574..3c2e628d01 100644
--- a/lib/mount/fs.go
+++ b/lib/mount/fs.go
@@ -5,6 +5,7 @@
 package mount
 
 import (
+	"errors"
 	"io"
 	"log"
 	"os"
@@ -36,7 +37,7 @@ type keepFS struct {
 	root   arvados.CustomFileSystem
 	open   map[uint64]*sharedFile
 	lastFH uint64
-	sync.Mutex
+	sync.RWMutex
 
 	// If non-nil, this channel will be closed by Init() to notify
 	// other goroutines that the mount is ready.
@@ -62,8 +63,8 @@ func (fs *keepFS) newFH(f arvados.File) uint64 {
 }
 
 func (fs *keepFS) lookupFH(fh uint64) *sharedFile {
-	fs.Lock()
-	defer fs.Unlock()
+	fs.RLock()
+	defer fs.RUnlock()
 	return fs.open[fh]
 }
 
@@ -121,23 +122,25 @@ func (fs *keepFS) Utimens(path string, tmsp []fuse.Timespec) int {
 }
 
 func (fs *keepFS) errCode(err error) int {
-	if os.IsNotExist(err) {
+	if err == nil {
+		return 0
+	}
+	if errors.Is(err, os.ErrNotExist) {
 		return -fuse.ENOENT
 	}
-	switch err {
-	case os.ErrExist:
+	if errors.Is(err, os.ErrExist) {
 		return -fuse.EEXIST
-	case arvados.ErrInvalidArgument:
+	}
+	if errors.Is(err, arvados.ErrInvalidArgument) {
 		return -fuse.EINVAL
-	case arvados.ErrInvalidOperation:
+	}
+	if errors.Is(err, arvados.ErrInvalidOperation) {
 		return -fuse.ENOSYS
-	case arvados.ErrDirectoryNotEmpty:
+	}
+	if errors.Is(err, arvados.ErrDirectoryNotEmpty) {
 		return -fuse.ENOTEMPTY
-	case nil:
-		return 0
-	default:
-		return -fuse.EIO
 	}
+	return -fuse.EIO
 }
 
 func (fs *keepFS) Mkdir(path string, mode uint32) int {
@@ -252,11 +255,18 @@ func (fs *keepFS) Chmod(path string, mode uint32) (errc int) {
 	}
 	if fi, err := fs.root.Stat(path); err != nil {
 		return fs.errCode(err)
-	} else if mode & ^uint32(fuse.S_IFREG|fuse.S_IFDIR|0777) != 0 || (fi.Mode()&os.ModeDir != 0) != (mode&fuse.S_IFDIR != 0) {
+	} else if mode & ^uint32(fuse.S_IFREG|fuse.S_IFDIR|0777) != 0 {
+		// Refuse to set mode bits other than
+		// regfile/dir/perms
+		return -fuse.ENOSYS
+	} else if (fi.Mode()&os.ModeDir != 0) != (mode&fuse.S_IFDIR != 0) {
+		// Refuse to transform a regular file to a dir, or
+		// vice versa
 		return -fuse.ENOSYS
-	} else {
-		return 0
 	}
+	// As long as the change isn't nonsense, chmod is a no-op,
+	// because we don't save permission bits.
+	return 0
 }
 
 func (fs *keepFS) fillStat(stat *fuse.Stat_t, fi os.FileInfo) {