diff --git a/sys/kern/kern_descrip.c b/sys/kern/kern_descrip.c
--- a/sys/kern/kern_descrip.c
+++ b/sys/kern/kern_descrip.c
@@ -4172,6 +4172,29 @@
 		vrele(olddp);
 }
 
+int
+descrip_check_write_mp(struct filedesc *fdp, struct mount *mp)
+{
+	struct file *fp;
+	struct vnode *vp;
+	int error, i;
+
+	error = 0;
+	FILEDESC_SLOCK(fdp);
+	FILEDESC_FOREACH_FP(fdp, i, fp) {
+		if (fp->f_type != DTYPE_VNODE ||
+		    (atomic_load_int(&fp->f_flag) & FWRITE) == 0)
+			continue;
+		vp = fp->f_vnode;
+		if (vp->v_mount == mp) {
+			error = EDEADLK;
+			break;
+		}
+	}
+	FILEDESC_SUNLOCK(fdp);
+	return (error);
+}
+
 struct filedesc_to_leader *
 filedesc_to_leader_alloc(struct filedesc_to_leader *old, struct filedesc *fdp,
     struct proc *leader)
diff --git a/sys/sys/filedesc.h b/sys/sys/filedesc.h
--- a/sys/sys/filedesc.h
+++ b/sys/sys/filedesc.h
@@ -225,6 +225,7 @@
 #define	falloc(td, resultfp, resultfd, flags) \
 	falloc_caps(td, resultfp, resultfd, flags, NULL)
 
+struct mount;
 struct thread;
 
 static __inline void
@@ -241,6 +242,7 @@
 
 int	closef(struct file *fp, struct thread *td);
 void	closef_nothread(struct file *fp);
+int	descrip_check_write_mp(struct filedesc *fdp, struct mount *mp);
 int	dupfdopen(struct thread *td, struct filedesc *fdp, int dfd, int mode,
 	    int openerror, int *indxp);
 int	falloc_caps(struct thread *td, struct file **resultfp, int *resultfd,
diff --git a/sys/ufs/ffs/ffs_suspend.c b/sys/ufs/ffs/ffs_suspend.c
--- a/sys/ufs/ffs/ffs_suspend.c
+++ b/sys/ufs/ffs/ffs_suspend.c
@@ -33,15 +33,15 @@
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
-#include <sys/param.h>
 #include <sys/systm.h>
 #include <sys/buf.h>
-#include <sys/ioccom.h>
-#include <sys/mount.h>
-#include <sys/vnode.h>
 #include <sys/conf.h>
+#include <sys/filedesc.h>
+#include <sys/ioccom.h>
 #include <sys/jail.h>
+#include <sys/mount.h>
 #include <sys/sx.h>
+#include <sys/vnode.h>
 
 #include <security/mac/mac_framework.h>
 
@@ -303,6 +303,16 @@
 		vfs_rel(mp);
 		if (error != 0)
 			break;
+
+		/*
+		 * Require single-thread curproc so that the check is not racey.
+		 * XXXKIB: might consider to singlethread curproc instead.
+		 */
+		error = curproc->p_numthreads > 1 ? EDEADLK :
+		    descrip_check_write_mp(curproc->p_fd, mp);
+		if (error != 0)
+			break;
+
 		error = ffs_susp_suspend(mp);
 		if (error != 0) {
 			vfs_unbusy(mp);