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 2007 Sun Microsystems, Inc.  All rights reserved.
  23  * Use is subject to license terms.
  24  */
  25 
  26 #pragma ident   "%Z%%M% %I%     %E% SMI"
  27 
  28 /*
  29  * The 'missing' vdev is a special vdev type used only during import.  It
  30  * signifies a placeholder in the root vdev for some vdev that we know is
  31  * missing.  We pass it down to the kernel to allow the rest of the
  32  * configuration to parsed and an attempt made to open all available devices.
  33  * Because its GUID is always 0, we know that the guid sum will mismatch and we
  34  * won't be able to open the pool anyway.
  35  */
  36 
  37 #include <sys/zfs_context.h>
  38 #include <sys/spa.h>
  39 #include <sys/vdev_impl.h>
  40 #include <sys/fs/zfs.h>
  41 #include <sys/zio.h>
  42 
  43 /* ARGSUSED */
  44 static int
  45 vdev_missing_open(vdev_t *vd, uint64_t *psize, uint64_t *ashift)
  46 {
  47         /*
  48          * Really this should just fail.  But then the root vdev will be in the
  49          * faulted state with VDEV_AUX_NO_REPLICAS, when what we really want is
  50          * VDEV_AUX_BAD_GUID_SUM.  So we pretend to succeed, knowing that we
  51          * will fail the GUID sum check before ever trying to open the pool.
  52          */
  53         *psize = SPA_MINDEVSIZE;
  54         *ashift = SPA_MINBLOCKSHIFT;
  55         return (0);
  56 }
  57 
  58 /* ARGSUSED */
  59 static void
  60 vdev_missing_close(vdev_t *vd)
  61 {
  62 }
  63 
  64 /* ARGSUSED */
  65 static int
  66 vdev_missing_io_start(zio_t *zio)
  67 {
  68         zio->io_error = ENOTSUP;
  69         return (ZIO_PIPELINE_CONTINUE);
  70 }
  71 
  72 /* ARGSUSED */
  73 static int
  74 vdev_missing_io_done(zio_t *zio)
  75 {
  76         return (ZIO_PIPELINE_CONTINUE);
  77 }
  78 
  79 /* ARGSUSED */
  80 static int
  81 vdev_missing_probe(vdev_t *vd)
  82 {
  83         return (0);
  84 }
  85 
  86 vdev_ops_t vdev_missing_ops = {
  87         vdev_missing_open,
  88         vdev_missing_close,
  89         vdev_missing_probe,
  90         vdev_default_asize,
  91         vdev_missing_io_start,
  92         vdev_missing_io_done,
  93         NULL,
  94         VDEV_TYPE_MISSING,      /* name of this vdev type */
  95         B_TRUE                  /* leaf vdev */
  96 };