usr/src/uts/common/fs/zfs/vdev_missing.c

   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 2010 Sun Microsystems, Inc.  All rights reserved.
  23  * Use is subject to license terms.
  24  */
  25
  26 /*
  27  * Copyright (c) 2012, 2016 by Delphix. All rights reserved.
  28  * Copyright 2019 Joyent, Inc.
  29  */
  30
  31 /*
  32  * The 'missing' vdev is a special vdev type used only during import.  It
  33  * signifies a placeholder in the root vdev for some vdev that we know is
  34  * missing.  We pass it down to the kernel to allow the rest of the
  35  * configuration to parsed and an attempt made to open all available devices.
  36  * Because its GUID is always 0, we know that the guid sum will mismatch and we
  37  * won't be able to open the pool anyway.
  38  */
  39
  40 #include <sys/zfs_context.h>
  41 #include <sys/spa.h>
  42 #include <sys/vdev_impl.h>
  43 #include <sys/fs/zfs.h>
  44 #include <sys/zio.h>
  45
  46 /* ARGSUSED */
  47 static int
  48 vdev_missing_open(vdev_t *vd, uint64_t *psize, uint64_t *max_psize,
  49     uint64_t *ashift)
  50 {
  51         /*
  52          * Really this should just fail.  But then the root vdev will be in the
  53          * faulted state with VDEV_AUX_NO_REPLICAS, when what we really want is
  54          * VDEV_AUX_BAD_GUID_SUM.  So we pretend to succeed, knowing that we
  55          * will fail the GUID sum check before ever trying to open the pool.
  56          */
  57         *psize = 0;
  58         *max_psize = 0;
  59         *ashift = 0;
  60         return (0);
  61 }
  62
  63 /* ARGSUSED */
  64 static void
  65 vdev_missing_close(vdev_t *vd)
  66 {
  67 }
  68
  69 /* ARGSUSED */
  70 static void
  71 vdev_missing_io_start(zio_t *zio)
  72 {
  73         zio->io_error = SET_ERROR(ENOTSUP);
  74         zio_execute(zio);
  75 }
  76
  77 /* ARGSUSED */
  78 static void
  79 vdev_missing_io_done(zio_t *zio)
  80 {
  81 }
  82
  83 vdev_ops_t vdev_missing_ops = {
  84         .vdev_op_open = vdev_missing_open,
  85         .vdev_op_close = vdev_missing_close,
  86         .vdev_op_asize = vdev_default_asize,
  87         .vdev_op_io_start = vdev_missing_io_start,
  88         .vdev_op_io_done = vdev_missing_io_done,
  89         .vdev_op_state_change = NULL,
  90         .vdev_op_need_resilver = NULL,
  91         .vdev_op_hold = NULL,
  92         .vdev_op_rele = NULL,
  93         .vdev_op_remap = NULL,
  94         .vdev_op_xlate = NULL,
  95         .vdev_op_dumpio = NULL,
  96         .vdev_op_type = VDEV_TYPE_MISSING,      /* name of this vdev type */
  97         .vdev_op_leaf = B_TRUE                  /* leaf vdev */
  98 };
  99
 100 vdev_ops_t vdev_hole_ops = {
 101         .vdev_op_open = vdev_missing_open,
 102         .vdev_op_close = vdev_missing_close,
 103         .vdev_op_asize = vdev_default_asize,
 104         .vdev_op_io_start = vdev_missing_io_start,
 105         .vdev_op_io_done = vdev_missing_io_done,
 106         .vdev_op_state_change = NULL,
 107         .vdev_op_need_resilver = NULL,
 108         .vdev_op_hold = NULL,
 109         .vdev_op_rele = NULL,
 110         .vdev_op_remap = NULL,
 111         .vdev_op_xlate = NULL,
 112         .vdev_op_dumpio = NULL,
 113         .vdev_op_type = VDEV_TYPE_HOLE,         /* name of this vdev type */
 114         .vdev_op_leaf = B_TRUE                  /* leaf vdev */
 115 };