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dm_target_error.c revision 1.21 
      1 /*        $NetBSD: dm_target_error.c,v 1.21 2019/12/15 05:56:02 tkusumi 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 #include <sys/cdefs.h>
     32 __KERNEL_RCSID(0, "$NetBSD: dm_target_error.c,v 1.21 2019/12/15 05:56:02 tkusumi Exp $");
     33 
     34 /*
     35  * This file implements initial version of device-mapper error target.
     36  */
     37 #include <sys/types.h>
     38 #include <sys/param.h>
     39 
     40 #include <sys/buf.h>
     41 
     42 #include "dm.h"
     43 
     44 /* dm_target_error.c */
     45 int dm_target_error_init(dm_table_entry_t*, int, char **);
     46 char *dm_target_error_table(void *);
     47 int dm_target_error_strategy(dm_table_entry_t *, struct buf *);
     48 int dm_target_error_sync(dm_table_entry_t *);
     49 int dm_target_error_deps(dm_table_entry_t *, prop_array_t);
     50 int dm_target_error_destroy(dm_table_entry_t *);
     51 int dm_target_error_upcall(dm_table_entry_t *, struct buf *);
     52 
     53 #ifdef DM_TARGET_MODULE
     54 /*
     55  * Every target can be compiled directly to dm driver or as a
     56  * separate module this part of target is used for loading targets
     57  * to dm driver.
     58  * Target can be unloaded from kernel only if there are no users of
     59  * it e.g. there are no devices which uses that target.
     60  */
     61 #include <sys/kernel.h>
     62 #include <sys/module.h>
     63 
     64 MODULE(MODULE_CLASS_MISC, dm_target_error, "dm");
     65 
     66 static int
     67 dm_target_error_modcmd(modcmd_t cmd, void *arg)
     68 {
     69 	dm_target_t *dmt;
     70 	int r;
     71 	dmt = NULL;
     72 
     73 	switch (cmd) {
     74 	case MODULE_CMD_INIT:
     75 		if ((dmt = dm_target_lookup("error")) != NULL) {
     76 			dm_target_unbusy(dmt);
     77 			return EEXIST;
     78 		}
     79 		dmt = dm_target_alloc("error");
     80 
     81 		dmt->version[0] = 1;
     82 		dmt->version[1] = 0;
     83 		dmt->version[2] = 0;
     84 		dmt->init = &dm_target_error_init;
     85 		dmt->table = &dm_target_error_table;
     86 		dmt->strategy = &dm_target_error_strategy;
     87 		dmt->sync = &dm_target_error_sync;
     88 		dmt->deps = &dm_target_error_deps;
     89 		dmt->destroy = &dm_target_error_destroy;
     90 		dmt->upcall = &dm_target_error_upcall;
     91 		dmt->secsize = dm_target_dummy_secsize;
     92 
     93 		r = dm_target_insert(dmt);
     94 
     95 		break;
     96 
     97 	case MODULE_CMD_FINI:
     98 		r = dm_target_rem("error");
     99 		break;
    100 
    101 	case MODULE_CMD_STAT:
    102 		return ENOTTY;
    103 
    104 	default:
    105 		return ENOTTY;
    106 	}
    107 
    108 	return r;
    109 }
    110 #endif
    111 
    112 /* Init function called from dm_table_load_ioctl. */
    113 int
    114 dm_target_error_init(dm_table_entry_t *table_en, int argc, char **argv)
    115 {
    116 
    117 	printf("Error target init function called!!\n");
    118 
    119 	table_en->target_config = NULL;
    120 
    121 	return 0;
    122 }
    123 
    124 /* Table routine called to get params string. */
    125 char *
    126 dm_target_error_table(void *target_config)
    127 {
    128 	return NULL;
    129 }
    130 
    131 /* Strategy routine called from dm_strategy. */
    132 int
    133 dm_target_error_strategy(dm_table_entry_t *table_en, struct buf *bp)
    134 {
    135 
    136 	bp->b_error = EIO;
    137 	bp->b_resid = 0;
    138 
    139 	biodone(bp);
    140 
    141 	return 0;
    142 }
    143 
    144 /* Sync underlying disk caches. */
    145 int
    146 dm_target_error_sync(dm_table_entry_t *table_en)
    147 {
    148 
    149 	return 0;
    150 }
    151 
    152 /* Doesn't do anything here. */
    153 int
    154 dm_target_error_destroy(dm_table_entry_t *table_en)
    155 {
    156 	/* Unbusy target so we can unload it */
    157 	dm_target_unbusy(table_en->target);
    158 
    159 	return 0;
    160 }
    161 
    162 /* Doesn't not need to do anything here. */
    163 int
    164 dm_target_error_deps(dm_table_entry_t *table_en, prop_array_t prop_array)
    165 {
    166 	return 0;
    167 }
    168 
    169 /* Unsupported for this target. */
    170 int
    171 dm_target_error_upcall(dm_table_entry_t *table_en, struct buf *bp)
    172 {
    173 	return 0;
    174 }
    175