Home | History | Annotate | Download | only in zfs
      1 /*
      2  * CDDL HEADER START
      3  *
      4  * The contents of this file are subject to the terms of the
      5  * Common Development and Distribution License (the "License").
      6  * You may not use this file except in compliance with the License.
      7  *
      8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
      9  * or http://www.opensolaris.org/os/licensing.
     10  * See the License for the specific language governing permissions
     11  * and limitations under the License.
     12  *
     13  * When distributing Covered Code, include this CDDL HEADER in each
     14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
     15  * If applicable, add the following below this CDDL HEADER, with the
     16  * fields enclosed by brackets "[]" replaced with your own identifying
     17  * information: Portions Copyright [yyyy] [name of copyright owner]
     18  *
     19  * CDDL HEADER END
     20  */
     21 /*
     22  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
     23  * Use is subject to license terms.
     24  */
     25 
     26 /*
     27  * The 'missing' vdev is a special vdev type used only during import.  It
     28  * signifies a placeholder in the root vdev for some vdev that we know is
     29  * missing.  We pass it down to the kernel to allow the rest of the
     30  * configuration to parsed and an attempt made to open all available devices.
     31  * Because its GUID is always 0, we know that the guid sum will mismatch and we
     32  * won't be able to open the pool anyway.
     33  */
     34 
     35 #include <sys/zfs_context.h>
     36 #include <sys/spa.h>
     37 #include <sys/vdev_impl.h>
     38 #include <sys/fs/zfs.h>
     39 #include <sys/zio.h>
     40 
     41 /* ARGSUSED */
     42 static int
     43 vdev_missing_open(vdev_t *vd, uint64_t *psize, uint64_t *ashift)
     44 {
     45 	/*
     46 	 * Really this should just fail.  But then the root vdev will be in the
     47 	 * faulted state with VDEV_AUX_NO_REPLICAS, when what we really want is
     48 	 * VDEV_AUX_BAD_GUID_SUM.  So we pretend to succeed, knowing that we
     49 	 * will fail the GUID sum check before ever trying to open the pool.
     50 	 */
     51 	*psize = SPA_MINDEVSIZE;
     52 	*ashift = SPA_MINBLOCKSHIFT;
     53 	return (0);
     54 }
     55 
     56 /* ARGSUSED */
     57 static void
     58 vdev_missing_close(vdev_t *vd)
     59 {
     60 }
     61 
     62 /* ARGSUSED */
     63 static int
     64 vdev_missing_io_start(zio_t *zio)
     65 {
     66 	zio->io_error = ENOTSUP;
     67 	return (ZIO_PIPELINE_CONTINUE);
     68 }
     69 
     70 /* ARGSUSED */
     71 static void
     72 vdev_missing_io_done(zio_t *zio)
     73 {
     74 }
     75 
     76 vdev_ops_t vdev_missing_ops = {
     77 	vdev_missing_open,
     78 	vdev_missing_close,
     79 	vdev_default_asize,
     80 	vdev_missing_io_start,
     81 	vdev_missing_io_done,
     82 	NULL,
     83 	VDEV_TYPE_MISSING,	/* name of this vdev type */
     84 	B_TRUE			/* leaf vdev */
     85 };
     86