expandable RAID-Z

          --- old/usr/src/uts/common/fs/zfs/vdev_missing.c
          +++ new/usr/src/uts/common/fs/zfs/vdev_missing.c

   1    1  /*
   2    2   * CDDL HEADER START
   3    3   *
   4    4   * The contents of this file are subject to the terms of the
   5    5   * Common Development and Distribution License (the "License").
   6    6   * You may not use this file except in compliance with the License.
   7    7   *
   8    8   * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9    9   * or http://www.opensolaris.org/os/licensing.
  10   10   * See the License for the specific language governing permissions
  11   11   * and limitations under the License.
  12   12   *
  13   13   * When distributing Covered Code, include this CDDL HEADER in each
  14   14   * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15   15   * If applicable, add the following below this CDDL HEADER, with the
  16   16   * fields enclosed by brackets "[]" replaced with your own identifying
  17   17   * information: Portions Copyright [yyyy] [name of copyright owner]
  18   18   *
  19   19   * CDDL HEADER END
  20   20   */
  21   21  /*
  22   22   * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
  23   23   * Use is subject to license terms.
  24   24   */
  25   25  
  26   26  #pragma ident   "%Z%%M% %I%     %E% SMI"
  27   27  
  28   28  /*
  29   29   * The 'missing' vdev is a special vdev type used only during import.  It
  30   30   * signifies a placeholder in the root vdev for some vdev that we know is
  31   31   * missing.  We pass it down to the kernel to allow the rest of the
  32   32   * configuration to parsed and an attempt made to open all available devices.
  33   33   * Because its GUID is always 0, we know that the guid sum will mismatch and we
  34   34   * won't be able to open the pool anyway.
  35   35   */
  36   36  
  37   37  #include <sys/zfs_context.h>
  38   38  #include <sys/spa.h>
  39   39  #include <sys/vdev_impl.h>
  40   40  #include <sys/fs/zfs.h>
  41   41  #include <sys/zio.h>
  42   42  
  43   43  /* ARGSUSED */
  44   44  static int
  45   45  vdev_missing_open(vdev_t *vd, uint64_t *psize, uint64_t *ashift)
  46   46  {
  47   47          /*
  48   48           * Really this should just fail.  But then the root vdev will be in the
  49   49           * faulted state with VDEV_AUX_NO_REPLICAS, when what we really want is
  50   50           * VDEV_AUX_BAD_GUID_SUM.  So we pretend to succeed, knowing that we
  51   51           * will fail the GUID sum check before ever trying to open the pool.
  52   52           */
  53   53          *psize = SPA_MINDEVSIZE;
  54   54          *ashift = SPA_MINBLOCKSHIFT;
  55   55          return (0);
  56   56  }
  57   57  
  58   58  /* ARGSUSED */
  59   59  static void
  60   60  vdev_missing_close(vdev_t *vd)
  61   61  {
  62   62  }
  63   63  
  64   64  /* ARGSUSED */
  65   65  static int
  66   66  vdev_missing_io_start(zio_t *zio)
  67   67  {
  68   68          zio->io_error = ENOTSUP;
  69   69          return (ZIO_PIPELINE_CONTINUE);
  70   70  }
  71   71  
  72   72  /* ARGSUSED */
  73   73  static int
  74   74  vdev_missing_io_done(zio_t *zio)
  75   75  {
  76   76          return (ZIO_PIPELINE_CONTINUE);
  77   77  }
  78   78  
  79   79  /* ARGSUSED */
  80   80  static int
  81   81  vdev_missing_probe(vdev_t *vd)
  82   82  {
  83   83          return (0);

  84   84  }
  85   85  
  86   86  vdev_ops_t vdev_missing_ops = {
  87   87          vdev_missing_open,
  88   88          vdev_missing_close,
  89   89          vdev_missing_probe,
  90   90          vdev_default_asize,
  91   91          vdev_missing_io_start,
  92   92          vdev_missing_io_done,
  93   93          NULL,
       94 +        NULL,
  94   95          VDEV_TYPE_MISSING,      /* name of this vdev type */
  95   96          B_TRUE                  /* leaf vdev */
  96   97  };
    

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