diff --git a/sys/fs/ext2fs/ext2_alloc.c b/sys/fs/ext2fs/ext2_alloc.c
index c3bd29ba3c2..35e24c3bde2 100644
--- a/sys/fs/ext2fs/ext2_alloc.c
+++ b/sys/fs/ext2fs/ext2_alloc.c
@@ -408,7 +408,8 @@ ext2_valloc(struct vnode *pvp, int mode, struct ucred *cred, struct vnode **vpp)
 	/*
 	 * Set up a new generation number for this inode.
 	 */
-	ip->i_gen = arc4random();
+	while (ip->i_gen == 0 || ++ip->i_gen == 0)
+		ip->i_gen = arc4random();
 
 	vfs_timestamp(&ts);
 	ip->i_birthtime = ts.tv_sec;
diff --git a/sys/fs/ext2fs/ext2_vfsops.c b/sys/fs/ext2fs/ext2_vfsops.c
index 9f2b94c1e00..9f73357061d 100644
--- a/sys/fs/ext2fs/ext2_vfsops.c
+++ b/sys/fs/ext2fs/ext2_vfsops.c
@@ -998,7 +998,8 @@ ext2_vget(struct mount *mp, ino_t ino, int flags, struct vnode **vpp)
 	 * already have one. This should only happen on old filesystems.
 	 */
 	if (ip->i_gen == 0) {
-		ip->i_gen = random() + 1;
+		while (ip->i_gen == 0)
+			ip->i_gen = arc4random();
 		if ((vp->v_mount->mnt_flag & MNT_RDONLY) == 0)
 			ip->i_flag |= IN_MODIFIED;
 	}
diff --git a/sys/ufs/ffs/ffs_alloc.c b/sys/ufs/ffs/ffs_alloc.c
index 797a42b1235..0e4dc031606 100644
--- a/sys/ufs/ffs/ffs_alloc.c
+++ b/sys/ufs/ffs/ffs_alloc.c
@@ -1102,8 +1102,8 @@ ffs_valloc(pvp, mode, cred, vpp)
 	/*
 	 * Set up a new generation number for this inode.
 	 */
-	if (ip->i_gen == 0 || ++ip->i_gen == 0)
-		ip->i_gen = arc4random() / 2 + 1;
+	while (ip->i_gen == 0 || ++ip->i_gen == 0)
+		ip->i_gen = arc4random();
 	DIP_SET(ip, i_gen, ip->i_gen);
 	if (fs->fs_magic == FS_UFS2_MAGIC) {
 		vfs_timestamp(&ts);
@@ -2080,7 +2080,8 @@ ffs_nodealloccg(ip, cg, ipref, mode, unused)
 		bzero(ibp->b_data, (int)fs->fs_bsize);
 		dp2 = (struct ufs2_dinode *)(ibp->b_data);
 		for (i = 0; i < INOPB(fs); i++) {
-			dp2->di_gen = arc4random() / 2 + 1;
+			while (dp2->di_gen == 0)
+				dp2->di_gen = arc4random();
 			dp2++;
 		}
 		/*
diff --git a/sys/ufs/ffs/ffs_vfsops.c b/sys/ufs/ffs/ffs_vfsops.c
index 7ecb053a7cc..d644b73f4fb 100644
--- a/sys/ufs/ffs/ffs_vfsops.c
+++ b/sys/ufs/ffs/ffs_vfsops.c
@@ -1768,7 +1768,8 @@ ffs_vgetf(mp, ino, flags, vpp, ffs_flags)
 	 * already have one. This should only happen on old filesystems.
 	 */
 	if (ip->i_gen == 0) {
-		ip->i_gen = arc4random() / 2 + 1;
+		while (ip->i_gen == 0)
+			ip->i_gen = arc4random();
 		if ((vp->v_mount->mnt_flag & MNT_RDONLY) == 0) {
 			ip->i_flag |= IN_MODIFIED;
 			DIP_SET(ip, i_gen, ip->i_gen);