Index: sys/fs/devfs/devfs_vnops.c
===================================================================
--- sys/fs/devfs/devfs_vnops.c	(wersja 206664)
+++ sys/fs/devfs/devfs_vnops.c	(kopia robocza)
@@ -44,6 +44,7 @@
 #include <sys/systm.h>
 #include <sys/conf.h>
 #include <sys/dirent.h>
+#include <sys/disk.h>
 #include <sys/fcntl.h>
 #include <sys/file.h>
 #include <sys/filedesc.h>
@@ -557,6 +558,24 @@
 	return (vop_stdfsync(ap));
 }
 
+static off_t
+devfs_dev_size(struct vnode *vp)
+{
+	struct cdev *dev;
+	struct cdevsw *dsw;
+	off_t size;
+
+	if (vp->v_type != VCHR)
+		return (0);
+	dev = vp->v_rdev;
+	dsw = dev->si_devsw;
+	if (!(dsw->d_flags & D_DISK))
+		return (0);
+	if (dsw->d_ioctl(dev, DIOCGMEDIASIZE, (void *)&size, 0, curthread) != 0)
+		return (0);
+	return (size);
+}
+
 static int
 devfs_getattr(struct vop_getattr_args *ap)
 {
@@ -581,7 +600,7 @@
 	else if (vp->v_type == VDIR)
 		vap->va_size = vap->va_bytes = DEV_BSIZE;
 	else
-		vap->va_size = 0;
+		vap->va_size = devfs_dev_size(vp);
 	if (vp->v_type != VDIR)
 		vap->va_bytes = 0;
 	vap->va_blocksize = DEV_BSIZE;