tmpfs_getattr(): Return more correct allocated byte counts.

For VREG vnodes, return the resident page count (multiplied by PAGE_SIZE)
for the tmpfs node's anonymous VM object that stores actual file contents.

For all other vnodes, return the tmpfs_node's tn_size, which should not
be rounded to a page.

This change allows using stat(2) to identify a sparse file on tmpfs.

Reviewed by:	kib
MFC after:	1 week

1 files changed, 6 insertions, 2 deletions

diff --git a/sys/fs/tmpfs/tmpfs_vnops.c b/sys/fs/tmpfs/tmpfs_vnops.c
index 885f84cdf2b5..9bdb1e90917c 100644
--- a/sys/fs/tmpfs/tmpfs_vnops.c
+++ b/sys/fs/tmpfs/tmpfs_vnops.c
@@ -342,7 +342,7 @@ tmpfs_getattr(struct vop_getattr_args *v)
 {
 	struct vnode *vp = v->a_vp;
 	struct vattr *vap = v->a_vap;
-
+	vm_object_t obj;
 	struct tmpfs_node *node;
 
 	node = VP_TO_TMPFS_NODE(vp);
@@ -366,7 +366,11 @@ tmpfs_getattr(struct vop_getattr_args *v)
 	vap->va_flags = node->tn_flags;
 	vap->va_rdev = (vp->v_type == VBLK || vp->v_type == VCHR) ?
 		node->tn_rdev : NODEV;
-	vap->va_bytes = round_page(node->tn_size);
+	if (vp->v_type == VREG) {
+		obj = node->tn_reg.tn_aobj;
+		vap->va_bytes = (u_quad_t)obj->resident_page_count * PAGE_SIZE;
+	} else
+		vap->va_bytes = node->tn_size;
 	vap->va_filerev = 0;
 
 	return 0;