FreeBSD: incorporate changes to the VFS_QUOTACTL(9) KPI

VFS_QUOTACTL(9) has been updated to allow each filesystem to indicate
whether it has changed the busy state of the mount.  The filesystem
may still assume that its .vfs_quotactl entrypoint is always called
with the mount busied, but only needs to unbusy the mount (and clear
*mp_busy) if it does something that actually requires the mount to be
unbusied.  It no longer needs to blindly copy-paste the UFS protocol
for calling vfs_unbusy(9) for the Q_QUOTAOFF and Q_QUOTAON commands.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Jason Harmening <jason.harmening@gmail.com>
Closes openzfs#12052

module/os/freebsd/zfs/zfs_vfsops.c

@@ -102,7 +102,12 @@ SYSCTL_INT(_vfs_zfs_version, OID_AUTO, zpl, CTLFLAG_RD, &zfs_version_zpl, 0,
     "ZPL_VERSION");
 /* END CSTYLED */
 
+#if __FreeBSD_version >= 1400018
+static int zfs_quotactl(vfs_t *vfsp, int cmds, uid_t id, void *arg,
+    bool *mp_busy);
+#else
 static int zfs_quotactl(vfs_t *vfsp, int cmds, uid_t id, void *arg);
+#endif
 static int zfs_mount(vfs_t *vfsp);
 static int zfs_umount(vfs_t *vfsp, int fflag);
 static int zfs_root(vfs_t *vfsp, int flags, vnode_t **vpp);
@@ -267,7 +272,11 @@ zfs_getquota(zfsvfs_t *zfsvfs, uid_t id, int isgroup, struct dqblk64 *dqp)
 }
 
 static int
+#if __FreeBSD_version >= 1400018
+zfs_quotactl(vfs_t *vfsp, int cmds, uid_t id, void *arg, bool *mp_busy)
+#else
 zfs_quotactl(vfs_t *vfsp, int cmds, uid_t id, void *arg)
+#endif
 {
 	zfsvfs_t *zfsvfs = vfsp->vfs_data;
 	struct thread *td;
@@ -291,8 +300,10 @@ zfs_quotactl(vfs_t *vfsp, int cmds, uid_t id, void *arg)
 			break;
 		default:
 			error = EINVAL;
+#if __FreeBSD_version < 1400018
 			if (cmd == Q_QUOTAON || cmd == Q_QUOTAOFF)
 				vfs_unbusy(vfsp);
+#endif
 			goto done;
 		}
 	}
@@ -351,11 +362,15 @@ zfs_quotactl(vfs_t *vfsp, int cmds, uid_t id, void *arg)
 	case Q_QUOTAON:
 		// As far as I can tell, you can't turn quotas on or off on zfs
 		error = 0;
+#if __FreeBSD_version < 1400018
 		vfs_unbusy(vfsp);
+#endif
 		break;
 	case Q_QUOTAOFF:
 		error = ENOTSUP;
+#if __FreeBSD_version < 1400018
 		vfs_unbusy(vfsp);
+#endif
 		break;
 	case Q_SETQUOTA:
 		error = copyin(arg, &dqblk, sizeof (dqblk));