4 files changed, 105 insertions, 6 deletions
diff --git a/pkg/sentry/fsimpl/fuse/fusefs.go b/pkg/sentry/fsimpl/fuse/fusefs.go
index a1405f7c3..83c24ec25 100644
--- a/pkg/sentry/fsimpl/fuse/fusefs.go
+++ b/pkg/sentry/fsimpl/fuse/fusefs.go
@@ -226,3 +226,99 @@ func (i *inode) Open(ctx context.Context, rp *vfs.ResolvingPath, vfsd *vfs.Dentr
 	}
 	return fd.VFSFileDescription(), nil
 }
+
+// statFromFUSEAttr makes attributes from linux.FUSEAttr to linux.Statx. The
+// opts.Sync attribute is ignored since the synchronization is handled by the
+// FUSE server.
+func statFromFUSEAttr(attr linux.FUSEAttr, mask, devMinor uint32) linux.Statx {
+	var stat linux.Statx
+	stat.Blksize = attr.BlkSize
+	stat.DevMajor, stat.DevMinor = linux.UNNAMED_MAJOR, devMinor
+
+	rdevMajor, rdevMinor := linux.DecodeDeviceID(attr.Rdev)
+	stat.RdevMajor, stat.RdevMinor = uint32(rdevMajor), rdevMinor
+
+	if mask&linux.STATX_MODE != 0 {
+		stat.Mode = uint16(attr.Mode)
+	}
+	if mask&linux.STATX_NLINK != 0 {
+		stat.Nlink = attr.Nlink
+	}
+	if mask&linux.STATX_UID != 0 {
+		stat.UID = attr.UID
+	}
+	if mask&linux.STATX_GID != 0 {
+		stat.GID = attr.GID
+	}
+	if mask&linux.STATX_ATIME != 0 {
+		stat.Atime = linux.StatxTimestamp{
+			Sec:  int64(attr.Atime),
+			Nsec: attr.AtimeNsec,
+		}
+	}
+	if mask&linux.STATX_MTIME != 0 {
+		stat.Mtime = linux.StatxTimestamp{
+			Sec:  int64(attr.Mtime),
+			Nsec: attr.MtimeNsec,
+		}
+	}
+	if mask&linux.STATX_CTIME != 0 {
+		stat.Ctime = linux.StatxTimestamp{
+			Sec:  int64(attr.Ctime),
+			Nsec: attr.CtimeNsec,
+		}
+	}
+	if mask&linux.STATX_INO != 0 {
+		stat.Ino = attr.Ino
+	}
+	if mask&linux.STATX_SIZE != 0 {
+		stat.Size = attr.Size
+	}
+	if mask&linux.STATX_BLOCKS != 0 {
+		stat.Blocks = attr.Blocks
+	}
+	return stat
+}
+
+// Stat implements kernfs.Inode.Stat.
+func (i *inode) Stat(ctx context.Context, fs *vfs.Filesystem, opts vfs.StatOptions) (linux.Statx, error) {
+	fusefs := fs.Impl().(*filesystem)
+	conn := fusefs.conn
+	task, creds := kernel.TaskFromContext(ctx), auth.CredentialsFromContext(ctx)
+	if task == nil {
+		log.Warningf("couldn't get kernel task from context")
+		return linux.Statx{}, syserror.EINVAL
+	}
+
+	var in linux.FUSEGetAttrIn
+	// We don't set any attribute in the request, because in VFS2 fstat(2) will
+	// finally be translated into vfs.FilesystemImpl.StatAt() (see
+	// pkg/sentry/syscalls/linux/vfs2/stat.go), resulting in the same flow
+	// as stat(2). Thus GetAttrFlags and Fh variable will never be used in VFS2.
+	req, err := conn.NewRequest(creds, uint32(task.ThreadID()), i.Ino(), linux.FUSE_GETATTR, &in)
+	if err != nil {
+		return linux.Statx{}, err
+	}
+
+	res, err := conn.Call(task, req)
+	if err != nil {
+		return linux.Statx{}, err
+	}
+	if err := res.Error(); err != nil {
+		return linux.Statx{}, err
+	}
+
+	var out linux.FUSEGetAttrOut
+	if err := res.UnmarshalPayload(&out); err != nil {
+		return linux.Statx{}, err
+	}
+
+	// Set all metadata into kernfs.InodeAttrs.
+	if err := i.SetStat(ctx, fs, creds, vfs.SetStatOptions{
+		Stat: statFromFUSEAttr(out.Attr, linux.STATX_ALL, fusefs.devMinor),
+	}); err != nil {
+		return linux.Statx{}, err
+	}
+
+	return statFromFUSEAttr(out.Attr, opts.Mask, fusefs.devMinor), nil
+}
diff --git a/pkg/sentry/fsimpl/host/host.go b/pkg/sentry/fsimpl/host/host.go
index bf922c566..bd6caba06 100644
--- a/pkg/sentry/fsimpl/host/host.go
+++ b/pkg/sentry/fsimpl/host/host.go
@@ -552,7 +552,7 @@ func (f *fileDescription) Allocate(ctx context.Context, mode, offset, length uin
 		return syserror.ESPIPE
 	}
 
-	// TODO(gvisor.dev/issue/2923): Implement Allocate for non-pipe hostfds.
+	// TODO(gvisor.dev/issue/3589): Implement Allocate for non-pipe hostfds.
 	return syserror.EOPNOTSUPP
 }
 
diff --git a/pkg/sentry/syscalls/linux/vfs2/aio.go b/pkg/sentry/syscalls/linux/vfs2/aio.go
index 399b4f60c..42559bf69 100644
--- a/pkg/sentry/syscalls/linux/vfs2/aio.go
+++ b/pkg/sentry/syscalls/linux/vfs2/aio.go
@@ -144,6 +144,12 @@ func submitCallback(t *kernel.Task, id uint64, cb *linux.IOCallback, cbAddr user
 
 func getAIOCallback(t *kernel.Task, fd, eventFD *vfs.FileDescription, cbAddr usermem.Addr, cb *linux.IOCallback, ioseq usermem.IOSequence, aioCtx *mm.AIOContext) kernel.AIOCallback {
 	return func(ctx context.Context) {
+		// Release references after completing the callback.
+		defer fd.DecRef(ctx)
+		if eventFD != nil {
+			defer eventFD.DecRef(ctx)
+		}
+
 		if aioCtx.Dead() {
 			aioCtx.CancelPendingRequest()
 			return
@@ -169,8 +175,6 @@ func getAIOCallback(t *kernel.Task, fd, eventFD *vfs.FileDescription, cbAddr use
 			ev.Result = -int64(kernel.ExtractErrno(err, 0))
 		}
 
-		fd.DecRef(ctx)
-
 		// Queue the result for delivery.
 		aioCtx.FinishRequest(ev)
 
@@ -179,7 +183,6 @@ func getAIOCallback(t *kernel.Task, fd, eventFD *vfs.FileDescription, cbAddr use
 		// wake up.
 		if eventFD != nil {
 			eventFD.Impl().(*eventfd.EventFileDescription).Signal(1)
-			eventFD.DecRef(ctx)
 		}
 	}
 }
diff --git a/pkg/sentry/vfs/file_description.go b/pkg/sentry/vfs/file_description.go
index d3c1197e3..dcafffe57 100644
--- a/pkg/sentry/vfs/file_description.go
+++ b/pkg/sentry/vfs/file_description.go
@@ -289,7 +289,7 @@ func (fd *FileDescription) SetStatusFlags(ctx context.Context, creds *auth.Crede
 	if flags&linux.O_DIRECT != 0 && !fd.opts.AllowDirectIO {
 		return syserror.EINVAL
 	}
-	// TODO(jamieliu): FileDescriptionImpl.SetOAsync()?
+	// TODO(gvisor.dev/issue/1035): FileDescriptionImpl.SetOAsync()?
 	const settableFlags = linux.O_APPEND | linux.O_ASYNC | linux.O_DIRECT | linux.O_NOATIME | linux.O_NONBLOCK
 	fd.flagsMu.Lock()
 	if fd.asyncHandler != nil {
@@ -301,7 +301,7 @@ func (fd *FileDescription) SetStatusFlags(ctx context.Context, creds *auth.Crede
 			fd.asyncHandler.Unregister(fd)
 		}
 	}
-	fd.statusFlags = (oldFlags &^ settableFlags) | (flags & settableFlags)
+	atomic.StoreUint32(&fd.statusFlags, (oldFlags&^settableFlags)|(flags&settableFlags))
 	fd.flagsMu.Unlock()
 	return nil
 }