Add FUSE umount support

This change implements Release for the FUSE filesystem
and expected behaviors of the FUSE devices.
It includes several checks for aborted connection
in the path for making a request and a function
to abort all the ongoing FUSE requests in order.

1 files changed, 10 insertions, 1 deletions

diff --git a/pkg/sentry/fsimpl/fuse/connection.go b/pkg/sentry/fsimpl/fuse/connection.go
index 72eac4179..5960d9368 100644
--- a/pkg/sentry/fsimpl/fuse/connection.go
+++ b/pkg/sentry/fsimpl/fuse/connection.go
@@ -180,7 +180,6 @@ func newFUSEConnection(_ context.Context, fd *vfs.FileDescription, opts *filesys
 	// Mark the device as ready so it can be used. /dev/fuse can only be used if the FD was used to
 	// mount a FUSE filesystem.
 	fuseFD := fd.Impl().(*DeviceFD)
-	fuseFD.mounted = true
 
 	// Create the writeBuf for the header to be stored in.
 	hdrLen := uint32((*linux.FUSEHeaderOut)(nil).SizeBytes())
@@ -283,6 +282,16 @@ func (conn *connection) callFuture(t *kernel.Task, r *Request) (*futureResponse,
 
 // callFutureLocked makes a request to the server and returns a future response.
 func (conn *connection) callFutureLocked(t *kernel.Task, r *Request) (*futureResponse, error) {
+	// Check connected again holding conn.mu.
+	conn.mu.Lock()
+	if !conn.connected {
+		conn.mu.Unlock()
+		// we checked connected before,
+		// this must be due to aborted connection.
+		return nil, syserror.ECONNABORTED
+	}
+	conn.mu.Unlock()
+
 	conn.fd.queue.PushBack(r)
 	conn.fd.numActiveRequests++
 	fut := newFutureResponse(r)