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, 12 insertions, 0 deletions

diff --git a/pkg/sentry/fsimpl/fuse/fusefs.go b/pkg/sentry/fsimpl/fuse/fusefs.go
index 30725182a..f4ed73c12 100644
--- a/pkg/sentry/fsimpl/fuse/fusefs.go
+++ b/pkg/sentry/fsimpl/fuse/fusefs.go
@@ -29,6 +29,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
 	"gvisor.dev/gvisor/pkg/sentry/vfs"
 	"gvisor.dev/gvisor/pkg/syserror"
+	"gvisor.dev/gvisor/pkg/waiter"
 	"gvisor.dev/gvisor/tools/go_marshal/marshal"
 )
 
@@ -82,6 +83,9 @@ type filesystem struct {
 
 	// opts is the options the fusefs is initialized with.
 	opts *filesystemOptions
+
+	// umounted is true if filesystem.Release() has been called.
+	umounted bool
 }
 
 // Name implements vfs.FilesystemType.Name.
@@ -221,6 +225,14 @@ func newFUSEFilesystem(ctx context.Context, devMinor uint32, opts *filesystemOpt
 
 // Release implements vfs.FilesystemImpl.Release.
 func (fs *filesystem) Release(ctx context.Context) {
+	fs.umounted = true
+	fs.conn.Abort(ctx)
+
+	fs.conn.fd.mu.Lock()
+	// Notify all the waiters on this fd.
+	fs.conn.fd.waitQueue.Notify(waiter.EventIn)
+	fs.conn.fd.mu.Unlock()
+
 	fs.Filesystem.VFSFilesystem().VirtualFilesystem().PutAnonBlockDevMinor(fs.devMinor)
 	fs.Filesystem.Release(ctx)
 }