sys/dev/disk/dm/dm_target_error.c

   1 /*        $NetBSD: dm_target_error.c,v 1.10 2010/01/04 00:12:22 haad Exp $      */
   2
   3 /*
   4  * Copyright (c) 2008 The NetBSD Foundation, Inc.
   5  * All rights reserved.
   6  *
   7  * This code is derived from software contributed to The NetBSD Foundation
   8  * by Adam Hamsik.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  29  * POSSIBILITY OF SUCH DAMAGE.
  30  */
  31
  32 /*
  33  * This file implements initial version of device-mapper error target.
  34  */
  35 #include <dev/disk/dm/dm.h>
  36
  37 /* Init function called from dm_table_load_ioctl. */
  38 static int
  39 dm_target_error_init(dm_table_entry_t *table_en, int argc, char **argv)
  40 {
  41         return 0;
  42 }
  43
  44 /* Strategy routine called from dm_strategy. */
  45 static int
  46 dm_target_error_strategy(dm_table_entry_t *table_en, struct buf *bp)
  47 {
  48         bp->b_error = EIO;
  49         bp->b_resid = 0;
  50
  51         biodone(&bp->b_bio1);
  52
  53         return 0;
  54 }
  55
  56 /* Doesn't do anything here. */
  57 static int
  58 dm_target_error_destroy(dm_table_entry_t *table_en)
  59 {
  60         return 0;
  61 }
  62
  63 static int
  64 dmte_mod_handler(module_t mod, int type, void *unused)
  65 {
  66         dm_target_t *dmt = NULL;
  67         int err = 0;
  68
  69         switch(type) {
  70         case MOD_LOAD:
  71                 if ((dmt = dm_target_lookup("error")) != NULL) {
  72                         dm_target_unbusy(dmt);
  73                         return EEXIST;
  74                 }
  75                 dmt = dm_target_alloc("error");
  76                 dmt->version[0] = 1;
  77                 dmt->version[1] = 0;
  78                 dmt->version[2] = 0;
  79                 dmt->init = &dm_target_error_init;
  80                 dmt->destroy = &dm_target_error_destroy;
  81                 dmt->strategy = &dm_target_error_strategy;
  82
  83                 err = dm_target_insert(dmt);
  84                 if (err == 0)
  85                         kprintf("dm_target_error: Successfully initialized\n");
  86                 break;
  87
  88         case MOD_UNLOAD:
  89                 err = dm_target_remove("error");
  90                 if (err == 0)
  91                         kprintf("dm_target_error: unloaded\n");
  92                 break;
  93         }
  94
  95         return err;
  96 }
  97
  98 DM_TARGET_BUILTIN(dm_target_error, dmte_mod_handler);