X-Git-Url: https://git.arvados.org/arvados.git/blobdiff_plain/44ddbde1cd9945778ed7e4ae1d96c65e24f17742..da7b5d99516353f6408e5a9bf640374cf3126e2e:/lib/mount/fs.go

diff --git a/lib/mount/fs.go b/lib/mount/fs.go
index 774948f574..c008b96af6 100644
--- a/lib/mount/fs.go
+++ b/lib/mount/fs.go
@@ -36,7 +36,7 @@ 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 +62,8 @@ 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]
 }
 
@@ -252,11 +252,18 @@ 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) {