diff --git a/share/man/man9/vn_deallocate.9 b/share/man/man9/vn_deallocate.9
--- a/share/man/man9/vn_deallocate.9
+++ b/share/man/man9/vn_deallocate.9
@@ -27,7 +27,7 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.Dd Jul 30, 2021
+.Dd August 11, 2021
 .Dt VN_DEALLOCATE 9
 .Os
 .Sh NAME
@@ -42,7 +42,7 @@
 .Fa "off_t *offset"
 .Fa "off_t *length"
 .Fa "int flags"
-.Fa "int ioflg"
+.Fa "int ioflag"
 .Fa "struct ucred *active_cred"
 .Fa "struct ucred *file_cred"
 .Fc
@@ -66,7 +66,7 @@
 .It Fa flags
 The control flags of the operation.
 This should be set to 0 for now.
-.It Fa ioflg
+.It Fa ioflag
 The control flags of vnode locking.
 .It Fa active_cred
 The user credentials of the calling thread.
@@ -75,7 +75,7 @@
 .El
 .Pp
 The
-.Fn ioflg
+.Fn ioflag
 argument may be one or more of the following flags:
 .Bl -tag -width IO_RANGELOCKED
 .It Dv IO_NODELOCKED
diff --git a/sys/kern/vfs_vnops.c b/sys/kern/vfs_vnops.c
--- a/sys/kern/vfs_vnops.c
+++ b/sys/kern/vfs_vnops.c
@@ -3447,7 +3447,7 @@
 
 static int
 vn_deallocate_impl(struct vnode *vp, off_t *offset, off_t *length, int flags,
-    int ioflg, struct ucred *active_cred, struct ucred *file_cred)
+    int ioflag, struct ucred *active_cred, struct ucred *file_cred)
 {
 	struct mount *mp;
 	void *rl_cookie;
@@ -3463,7 +3463,7 @@
 	off = *offset;
 	len = *length;
 
-	if ((ioflg & (IO_NODELOCKED|IO_RANGELOCKED)) == 0)
+	if ((ioflag & (IO_NODELOCKED | IO_RANGELOCKED)) == 0)
 		rl_cookie = vn_rangelock_wlock(vp, off, off + len);
 	while (len > 0 && error == 0) {
 		/*
@@ -3473,7 +3473,7 @@
 		 * pass.
 		 */
 
-		if ((ioflg & IO_NODELOCKED) == 0) {
+		if ((ioflag & IO_NODELOCKED) == 0) {
 			bwillwrite();
 			if ((error = vn_start_write(vp, &mp,
 			    V_WAIT | PCATCH)) != 0)
@@ -3488,7 +3488,7 @@
 #endif
 
 #ifdef MAC
-		if ((ioflg & IO_NOMACCHECK) == 0)
+		if ((ioflag & IO_NOMACCHECK) == 0)
 			error = mac_vnode_check_write(active_cred, file_cred,
 			    vp);
 #endif
@@ -3496,7 +3496,7 @@
 			error = VOP_DEALLOCATE(vp, &off, &len, flags,
 			    active_cred);
 
-		if ((ioflg & IO_NODELOCKED) == 0) {
+		if ((ioflag & IO_NODELOCKED) == 0) {
 			VOP_UNLOCK(vp);
 			if (mp != NULL) {
 				vn_finished_write(mp);
@@ -3514,7 +3514,7 @@
 
 int
 vn_deallocate(struct vnode *vp, off_t *offset, off_t *length, int flags,
-    int ioflg, struct ucred *active_cred, struct ucred *file_cred)
+    int ioflag, struct ucred *active_cred, struct ucred *file_cred)
 {
 	if (*offset < 0 || *length <= 0 || *length > OFF_MAX - *offset ||
 	    flags != 0)
@@ -3522,7 +3522,7 @@
 	if (vp->v_type != VREG)
 		return (ENODEV);
 
-	return (vn_deallocate_impl(vp, offset, length, flags, ioflg,
+	return (vn_deallocate_impl(vp, offset, length, flags, ioflag,
 	    active_cred, file_cred));
 }