Index: share/man/man9/Makefile
===================================================================
--- share/man/man9/Makefile
+++ share/man/man9/Makefile
@@ -2308,6 +2308,8 @@
 MLINKS+=vm_page_wire.9 vm_page_unwire.9
 MLINKS+=VOP_ACCESS.9 VOP_ACCESSX.9
 MLINKS+=VOP_ATTRIB.9 VOP_GETATTR.9 \
+	VOP_ATTRIB.9 VOP_UGETATTR_LITE.9 \
+	VOP_ATTRIB.9 VOP_GETATTR_LITE.9 \
 	VOP_ATTRIB.9 VOP_SETATTR.9 \
 	VOP_ATTRIB.9 VOP_STAT.9
 MLINKS+=VOP_CREATE.9 VOP_MKDIR.9 \
Index: share/man/man9/VOP_ATTRIB.9
===================================================================
--- share/man/man9/VOP_ATTRIB.9
+++ share/man/man9/VOP_ATTRIB.9
@@ -41,6 +41,10 @@
 .Ft int
 .Fn VOP_GETATTR "struct vnode *vp" "struct vattr *vap" "struct ucred *cred"
 .Ft int
+.Fn VOP_UGETATTR_LITE "struct vnode *vp" "struct vattr *vap" "struct ucred *cred"
+.Ft int
+.Fn VOP_GETATTR_LITE "struct vnode *vp" "struct vattr *vap" "struct ucred *cred"
+.Ft int
 .Fn VOP_SETATTR "struct vnode *vp" "struct vattr *vap" "struct ucred *cred"
 .Ft int
 .Fn VOP_STAT "struct vnode *vp" "struct stat *sb" "struct ucred *active_cred" \
@@ -57,8 +61,17 @@
 .Fn VOP_GETATTR .
 Filesystems may want to implement their own variant for performance reasons.
 .Pp
+.Fn VOP_UGETATTR_LITE
+can be used for lockless operation. It guarantees to not block if requested,
+but may fail to provide requested data as a result. Callers may want to fallback
+to
+.Fn VOP_GETATTR_LITE
+from a blocking context.
+.Pp
 For
-.Fn VOP_GETATTR
+.Fn VOP_GETATTR ,
+.Fn VOP_UGETATTR_LITE ,
+.Fn VOP_GETATTR_LITE
 and
 .Fn VOP_SETATTR
 the arguments are:
@@ -71,6 +84,14 @@
 The user credentials of the calling thread.
 .El
 .Pp
+Additionally
+.Fn VOP_UGETATTR_LITE
+accepts:
+.Bl -tag -width cred
+.It Fa flags
+LK_NOWAIT to demand non-blocking operation or 0 to allow it.
+.El
+.Pp
 For
 .Fn VOP_STAT
 the arguments are:
@@ -97,21 +118,27 @@
 .Fa *vap
 prior to setting specific values.
 .Sh LOCKS
-Both
-.Fn VOP_GETATTR
+.Fn VOP_GETATTR ,
+.Fn VOP_GETATTR_LITE
 and
 .Fn VOP_STAT
 expect the vnode to be locked on entry and will leave the vnode locked on
 return.
 The lock type can be either shared or exclusive.
 .Pp
+.Fn VOP_UGETATTR_LITE
+expects the vnode to be unlocked.
+.Pp
 .Fn VOP_SETATTR
 expects the vnode to be locked on entry and will leave the vnode locked on
 return.
 The lock type must be exclusive.
 .Sh RETURN VALUES
-.Fn VOP_GETATTR
-returns 0 if it was able to retrieve the attribute data via
+.Fn VOP_GETATTR ,
+.Fn VOP_UGETATTR_LITE
+and
+.Fn VOP_GETATTR_LITE
+return 0 if it was able to retrieve the attribute data via
 .Fa *vap ,
 otherwise an appropriate error is returned.
 .Fn VOP_SETATTR
@@ -130,6 +157,16 @@
 .It Bq Er EROFS
 The file system is read-only.
 .El
+.Pp
+Additionally
+.Fn VOP_GETATTR_LITE
+may return the following:
+.Bl -tag -width Er
+.It Bq Er ENOENT
+The vnode is doomed.
+.It Bq Er EAGAIN
+The requested operation could not be completed without blocking.
+.El
 .Sh SEE ALSO
 .Xr VFS 9 ,
 .Xr vnode 9 ,
Index: sys/fs/tmpfs/tmpfs_vnops.h
===================================================================
--- sys/fs/tmpfs/tmpfs_vnops.h
+++ sys/fs/tmpfs/tmpfs_vnops.h
@@ -51,6 +51,8 @@
 vop_access_t	tmpfs_access;
 vop_fplookup_vexec_t tmpfs_fplookup_vexec;
 vop_stat_t	tmpfs_stat;
+vop_ugetattr_lite_t	tmpfs_ugetattr_lite;
+vop_getattr_lite_t	tmpfs_getattr_lite;
 vop_getattr_t	tmpfs_getattr;
 vop_setattr_t	tmpfs_setattr;
 vop_pathconf_t	tmpfs_pathconf;
Index: sys/fs/tmpfs/tmpfs_vnops.c
===================================================================
--- sys/fs/tmpfs/tmpfs_vnops.c
+++ sys/fs/tmpfs/tmpfs_vnops.c
@@ -453,6 +453,49 @@
 	return (vop_stat_helper_post(v, error));
 }
 
+static void __inline
+tmpfs_getattr_lite_fill(struct vnode *vp, struct tmpfs_node *node,
+    struct vattr_lite *lvap)
+{
+
+	lvap->va_size = node->tn_size;
+	lvap->va_nlink = node->tn_links;
+	lvap->va_type = vp->v_type;
+	lvap->va_mode = node->tn_mode;
+	lvap->va_uid = node->tn_uid;
+	lvap->va_gid = node->tn_gid;
+}
+
+int
+tmpfs_ugetattr_lite(struct vop_ugetattr_lite_args *v)
+{
+	struct vnode *vp = v->a_vp;
+	struct vattr_lite *lvap = v->a_lvap;
+	struct tmpfs_node *node;
+
+	vfs_smr_enter();
+	node = VP_TO_TMPFS_NODE_SMR(vp);
+	if (__predict_false(node == NULL)) {
+		vfs_smr_exit();
+		return (ENOENT);
+	}
+	tmpfs_getattr_lite_fill(vp, node, lvap);
+	vfs_smr_exit();
+	return (0);
+}
+
+int
+tmpfs_getattr_lite(struct vop_getattr_lite_args *v)
+{
+	struct vnode *vp = v->a_vp;
+	struct vattr_lite *lvap = v->a_lvap;
+	struct tmpfs_node *node;
+
+	node = VP_TO_TMPFS_NODE(vp);
+	tmpfs_getattr_lite_fill(vp, node, lvap);
+	return (0);
+}
+
 int
 tmpfs_getattr(struct vop_getattr_args *v)
 {
@@ -1724,6 +1767,8 @@
 	.vop_fplookup_vexec =		tmpfs_fplookup_vexec,
 	.vop_access =			tmpfs_access,
 	.vop_stat =			tmpfs_stat,
+	.vop_ugetattr_lite =		tmpfs_ugetattr_lite,
+	.vop_getattr_lite =		tmpfs_getattr_lite,
 	.vop_getattr =			tmpfs_getattr,
 	.vop_setattr =			tmpfs_setattr,
 	.vop_read =			tmpfs_read,
Index: sys/kern/imgact_elf.c
===================================================================
--- sys/kern/imgact_elf.c
+++ sys/kern/imgact_elf.c
@@ -738,13 +738,13 @@
 {
 	struct {
 		struct nameidata nd;
-		struct vattr attr;
+		struct vattr_lite attr;
 		struct image_params image_params;
 	} *tempdata;
 	const Elf_Ehdr *hdr = NULL;
 	const Elf_Phdr *phdr = NULL;
 	struct nameidata *nd;
-	struct vattr *attr;
+	struct vattr_lite *attr;
 	struct image_params *imgp;
 	u_long rbase;
 	u_long base_addr = 0;
Index: sys/kern/kern_exec.c
===================================================================
--- sys/kern/kern_exec.c
+++ sys/kern/kern_exec.c
@@ -365,7 +365,7 @@
 	struct uidinfo *euip = NULL;
 	uintptr_t stack_base;
 	struct image_params image_params, *imgp;
-	struct vattr attr;
+	struct vattr_lite attr;
 	int (*img_first)(struct image_params *);
 	struct pargs *oldargs = NULL, *newargs = NULL;
 	struct sigacts *oldsigacts = NULL, *newsigacts = NULL;
@@ -1706,14 +1706,14 @@
 exec_check_permissions(struct image_params *imgp)
 {
 	struct vnode *vp = imgp->vp;
-	struct vattr *attr = imgp->attr;
+	struct vattr_lite *attr = imgp->attr;
 	struct thread *td;
 	int error;
 
 	td = curthread;
 
 	/* Get file attributes */
-	error = VOP_GETATTR(vp, attr, td->td_ucred);
+	error = VOP_GETATTR_LITE(vp, attr, td->td_ucred);
 	if (error)
 		return (error);
 
Index: sys/kern/vfs_default.c
===================================================================
--- sys/kern/vfs_default.c
+++ sys/kern/vfs_default.c
@@ -89,6 +89,8 @@
 static int vop_stdadd_writecount(struct vop_add_writecount_args *ap);
 static int vop_stdcopy_file_range(struct vop_copy_file_range_args *ap);
 static int vop_stdfdatasync(struct vop_fdatasync_args *ap);
+static int vop_stdugetattr_lite(struct vop_ugetattr_lite_args *ap);
+static int vop_stdgetattr_lite(struct vop_getattr_lite_args *ap);
 static int vop_stdgetpages_async(struct vop_getpages_async_args *ap);
 static int vop_stdstat(struct vop_stat_args *ap);
 
@@ -120,6 +122,8 @@
 	.vop_fsync =		VOP_NULL,
 	.vop_stat =		vop_stdstat,
 	.vop_fdatasync =	vop_stdfdatasync,
+	.vop_ugetattr_lite =	vop_stdugetattr_lite,
+	.vop_getattr_lite =	vop_stdgetattr_lite,
 	.vop_getpages =		vop_stdgetpages,
 	.vop_getpages_async =	vop_stdgetpages_async,
 	.vop_getwritemount = 	vop_stdgetwritemount,
@@ -749,6 +753,51 @@
 	return (vn_fsync_buf(ap->a_vp, MNT_WAIT));
 }
 
+int
+vop_stdugetattr_lite(struct vop_ugetattr_lite_args *ap)
+{
+	struct vnode *vp;
+	struct ucred *cred;
+	struct vattr_lite *lvap;
+	int error, flags;
+
+	vp = ap->a_vp;
+	cred = ap->a_cred;
+	lvap = ap->a_lvap;
+	flags = ap->a_flags;
+	error = VOP_LOCK(vp, LK_SHARED | flags);
+	if (error != 0)
+		return (EAGAIN);
+	error = VOP_GETATTR_LITE(vp, lvap, cred);
+	VOP_UNLOCK(vp);
+	return (error);
+}
+
+int
+vop_stdgetattr_lite(struct vop_getattr_lite_args *ap)
+{
+	struct vnode *vp;
+	struct ucred *cred;
+	struct vattr vattr;
+	struct vattr_lite *lvap;
+	int error;
+
+	vp = ap->a_vp;
+	cred = ap->a_cred;
+	error = VOP_GETATTR(vp, &vattr, cred);
+	if (error != 0)
+		return (error);
+
+	lvap = ap->a_lvap;
+	lvap->va_size = vattr.va_size;
+	lvap->va_nlink = vattr.va_nlink;
+	lvap->va_type = vattr.va_type;
+	lvap->va_mode = vattr.va_mode;
+	lvap->va_uid = vattr.va_uid;
+	lvap->va_gid = vattr.va_gid;
+	return (0);
+}
+
 /* XXX Needs good comment and more info in the manpage (VOP_GETPAGES(9)). */
 int
 vop_stdgetpages(ap)
Index: sys/kern/vfs_subr.c
===================================================================
--- sys/kern/vfs_subr.c
+++ sys/kern/vfs_subr.c
@@ -5655,6 +5655,85 @@
 
 	ASSERT_VI_LOCKED(a->a_vp, "VOP_NEED_INACTIVE");
 }
+
+static void
+vop_getattr_lite_debug_prefill(struct vattr_lite *lvap)
+{
+
+	lvap->va_size = VNOVAL;
+	lvap->va_nlink = VNOVAL;
+	lvap->va_type = VNON;
+	lvap->va_mode = 0xffff;
+	lvap->va_uid = VNOVAL;
+	lvap->va_gid = VNOVAL;
+}
+
+static void
+vop_getattr_lite_debug_validate(struct vnode *vp, struct vattr_lite *lvap)
+{
+
+	if (lvap->va_size == VNOVAL ||
+	    lvap->va_nlink == VNOVAL ||
+	    lvap->va_type == VNON ||
+	    lvap->va_mode == 0xffff ||
+	    lvap->va_uid == VNOVAL ||
+	    lvap->va_gid == VNOVAL) {
+		VNASSERT(0, vp,
+		    ("some fields got left uninitialized in vattr_lite"));
+	}
+}
+
+void
+vop_ugetattr_lite_debugpre(void *ap)
+{
+	struct vop_ugetattr_lite_args *a;
+	struct vattr_lite *lvap;
+	int flags;
+
+	a = ap;
+	flags = a->a_flags;
+	lvap = a->a_lvap;
+	KASSERT((flags & ~(LK_NOWAIT)) == 0,
+	    ("%s: unsupported flags %d passed\n", __func__, flags));
+	vop_getattr_lite_debug_prefill(lvap);
+}
+
+void
+vop_ugetattr_lite_debugpost(void *ap, int rc)
+{
+	struct vop_ugetattr_lite_args *a;
+	struct vnode *vp;
+	struct vattr_lite *lvap;
+
+	a = ap;
+	vp = a->a_vp;
+	lvap = a->a_lvap;
+	vop_getattr_lite_debug_validate(vp, lvap);
+}
+
+void
+vop_getattr_lite_debugpre(void *ap)
+{
+	struct vop_getattr_lite_args *a;
+	struct vattr_lite *lvap;
+
+	a = ap;
+	lvap = a->a_lvap;
+	vop_getattr_lite_debug_prefill(lvap);
+}
+
+void
+vop_getattr_lite_debugpost(void *ap, int rc)
+{
+	struct vop_getattr_lite_args *a;
+	struct vnode *vp;
+	struct vattr_lite *lvap;
+
+	a = ap;
+	vp = a->a_vp;
+	lvap = a->a_lvap;
+	vop_getattr_lite_debug_validate(vp, lvap);
+}
 #endif
 
 void
Index: sys/kern/vfs_vnops.c
===================================================================
--- sys/kern/vfs_vnops.c
+++ sys/kern/vfs_vnops.c
@@ -2250,7 +2250,7 @@
 {
 	struct ucred *cred;
 	struct vnode *vp;
-	struct vattr vattr;
+	struct vattr_lite vattr;
 	off_t foffset, size;
 	int error, noneg;
 
@@ -2270,9 +2270,7 @@
 		offset += foffset;
 		break;
 	case L_XTND:
-		vn_lock(vp, LK_SHARED | LK_RETRY);
-		error = VOP_GETATTR(vp, &vattr, cred);
-		VOP_UNLOCK(vp);
+		error = VOP_UGETATTR_LITE(vp, &vattr, cred, 0);
 		if (error)
 			break;
 
Index: sys/kern/vnode_if.src
===================================================================
--- sys/kern/vnode_if.src
+++ sys/kern/vnode_if.src
@@ -188,6 +188,29 @@
 };
 
 
+%% ugetattr_lite	vp	- - -
+%! ugetattr_lite	debugpre	vop_ugetattr_lite_debugpre
+%! ugetattr_lite	debugpost	vop_ugetattr_lite_debugpost
+
+vop_ugetattr_lite {
+	IN struct vnode *vp;
+	OUT struct vattr_lite *lvap;
+	IN struct ucred *cred;
+	IN int flags;
+};
+
+
+%% getattr_lite	vp	L L L
+%! getattr_lite	debugpre	vop_getattr_lite_debugpre
+%! getattr_lite	debugpost	vop_getattr_lite_debugpost
+
+vop_getattr_lite {
+	IN struct vnode *vp;
+	OUT struct vattr_lite *lvap;
+	IN struct ucred *cred;
+};
+
+
 %% getattr	vp	L L L
 
 vop_getattr {
Index: sys/sys/imgact.h
===================================================================
--- sys/sys/imgact.h
+++ sys/sys/imgact.h
@@ -63,7 +63,7 @@
 	struct label *execlabel;	/* optional exec label */
 	struct vnode *vp;	/* pointer to vnode of file to exec */
 	struct vm_object *object;	/* The vm object for this vp */
-	struct vattr *attr;	/* attributes of file */
+	struct vattr_lite *attr;	/* attributes of file */
 	const char *image_header; /* head of file to exec */
 	unsigned long entry_addr; /* entry address of target executable */
 	unsigned long reloc_base; /* load address of image */
Index: sys/sys/vnode.h
===================================================================
--- sys/sys/vnode.h
+++ sys/sys/vnode.h
@@ -296,6 +296,19 @@
 	long		va_spare;	/* remain quad aligned */
 };
 
+/*
+ * If you add fields to this structure make sure to update sanity checks
+ * in vop_getattr_lite_debug*
+ */
+struct vattr_lite {
+	u_quad_t	va_size;	/* file size in bytes */
+	nlink_t		va_nlink;	/* number of references to file */
+	enum vtype	va_type;	/* vnode type (for create) */
+	u_short		va_mode;	/* files access mode and type */
+	uid_t		va_uid;		/* owner user id */
+	gid_t		va_gid;		/* owner group id */
+};
+
 /*
  * Flags for va_vaflags.
  */
@@ -878,6 +891,10 @@
 void	vop_unlock_debugpre(void *a);
 void	vop_need_inactive_debugpre(void *a);
 void	vop_need_inactive_debugpost(void *a, int rc);
+void	vop_ugetattr_lite_debugpre(void *a);
+void	vop_ugetattr_lite_debugpost(void *a, int rc);
+void	vop_getattr_lite_debugpre(void *a);
+void	vop_getattr_lite_debugpost(void *a, int rc);
 #else
 #define	vop_fplookup_vexec_debugpre(x)		do { } while (0)
 #define	vop_fplookup_vexec_debugpost(x, y)	do { } while (0)
@@ -887,6 +904,10 @@
 #define	vop_unlock_debugpre(x)			do { } while (0)
 #define	vop_need_inactive_debugpre(x)		do { } while (0)
 #define	vop_need_inactive_debugpost(x, y)	do { } while (0)
+#define	vop_ugetattr_lite_debugpre(x)		do { } while (0)
+#define	vop_ugetattr_lite_debugpost(x, y)	do { } while (0)
+#define	vop_getattr_lite_debugpre(x)		do { } while (0)
+#define	vop_getattr_lite_debugpost(x, y)	do { } while (0)
 #endif
 
 void	vop_rename_fail(struct vop_rename_args *ap);
Index: sys/ufs/ufs/ufs_vnops.c
===================================================================
--- sys/ufs/ufs/ufs_vnops.c
+++ sys/ufs/ufs/ufs_vnops.c
@@ -109,6 +109,8 @@
 static vop_close_t	ufs_close;
 static vop_create_t	ufs_create;
 static vop_stat_t	ufs_stat;
+static vop_ugetattr_lite_t	ufs_ugetattr_lite;
+static vop_getattr_lite_t	ufs_getattr_lite;
 static vop_getattr_t	ufs_getattr;
 static vop_ioctl_t	ufs_ioctl;
 static vop_link_t	ufs_link;
@@ -526,6 +528,56 @@
 	return (vop_stat_helper_post(ap, error));
 }
 
+static void __inline
+ufs_getattr_lite_fill(struct inode *ip, struct vattr_lite *lvap)
+{
+
+	if (I_IS_UFS1(ip)) {
+		lvap->va_size = ip->i_din1->di_size;
+	} else {
+		lvap->va_size = ip->i_din2->di_size;
+	}
+	lvap->va_nlink = ip->i_effnlink;
+	lvap->va_type = IFTOVT(ip->i_mode);
+	lvap->va_mode = ip->i_mode & ~IFMT;
+	lvap->va_uid = ip->i_uid;
+	lvap->va_gid = ip->i_gid;
+}
+
+static int
+ufs_ugetattr_lite(struct vop_ugetattr_lite_args *ap)
+{
+	struct vnode *vp;
+	struct inode *ip;
+	struct vattr_lite *lvap;
+
+	vfs_smr_enter();
+	vp = ap->a_vp;
+	ip = VTOI_SMR(vp);
+	if (__predict_false(ip == NULL)) {
+		vfs_smr_exit();
+		return (ENOENT);
+	}
+	lvap = ap->a_lvap;
+	ufs_getattr_lite_fill(ip, lvap);
+	vfs_smr_exit();
+	return (0);
+}
+
+static int
+ufs_getattr_lite(struct vop_getattr_lite_args *ap)
+{
+	struct vnode *vp;
+	struct inode *ip;
+	struct vattr_lite *lvap;
+
+	vp = ap->a_vp;
+	ip = VTOI(vp);
+	lvap = ap->a_lvap;
+	ufs_getattr_lite_fill(ip, lvap);
+	return (0);
+}
+
 /* ARGSUSED */
 static int
 ufs_getattr(ap)
@@ -2884,6 +2936,8 @@
 	.vop_close =		ufs_close,
 	.vop_create =		ufs_create,
 	.vop_stat =		ufs_stat,
+	.vop_ugetattr_lite =	ufs_ugetattr_lite,
+	.vop_getattr_lite =	ufs_getattr_lite,
 	.vop_getattr =		ufs_getattr,
 	.vop_inactive =		ufs_inactive,
 	.vop_ioctl =		ufs_ioctl,