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      1 /*$NetBSD: dm_target_mirror.c,v 1.24 2020/01/21 16:27:53 tkusumi Exp $*/
      2 
      3 /*
      4  * Copyright (c) 2009 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Adam Hamsik.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 #include <sys/cdefs.h>
     32 __KERNEL_RCSID(0, "$NetBSD: dm_target_mirror.c,v 1.24 2020/01/21 16:27:53 tkusumi Exp $");
     33 
     34 /*
     35  * This file implements initial version of device-mapper mirror target.
     36  */
     37 #include <sys/types.h>
     38 #include <sys/param.h>
     39 #include <sys/buf.h>
     40 
     41 #include "dm.h"
     42 
     43 /* dm_target_mirror.c */
     44 int dm_target_mirror_init(dm_table_entry_t *, int, char **);
     45 char *dm_target_mirror_table(void *);
     46 int dm_target_mirror_strategy(dm_table_entry_t *, struct buf *);
     47 int dm_target_mirror_sync(dm_table_entry_t *);
     48 int dm_target_mirror_destroy(dm_table_entry_t *);
     49 //int dm_target_mirror_upcall(dm_table_entry_t *, struct buf *);
     50 
     51 typedef struct target_mirror_config {
     52 #define MAX_MIRROR_COPIES 4
     53 	dm_pdev_t *orig;
     54 	dm_pdev_t *copies[MAX_MIRROR_COPIES];
     55 
     56 	/* copied blocks bitmaps administration etc*/
     57 	dm_pdev_t *log_pdev;	/* for administration */
     58 	uint64_t log_regionsize;	/* blocksize of mirror */
     59 
     60 	/* list of parts that still need copied etc.; run length encoded? */
     61 } dm_target_mirror_config_t;
     62 
     63 #ifdef DM_TARGET_MODULE
     64 /*
     65  * Every target can be compiled directly to dm driver or as a
     66  * separate module this part of target is used for loading targets
     67  * to dm driver.
     68  * Target can be unloaded from kernel only if there are no users of
     69  * it e.g. there are no devices which uses that target.
     70  */
     71 #include <sys/kernel.h>
     72 #include <sys/module.h>
     73 
     74 MODULE(MODULE_CLASS_MISC, dm_target_mirror, "dm");
     75 
     76 static int
     77 dm_target_mirror_modcmd(modcmd_t cmd, void *arg)
     78 {
     79 	dm_target_t *dmt;
     80 	int r;
     81 
     82 	switch (cmd) {
     83 	case MODULE_CMD_INIT:
     84 		if ((dmt = dm_target_lookup("mirror")) != NULL) {
     85 			dm_target_unbusy(dmt);
     86 			return EEXIST;
     87 		}
     88 		dmt = dm_target_alloc("mirror");
     89 
     90 		dmt->version[0] = 1;
     91 		dmt->version[1] = 0;
     92 		dmt->version[2] = 0;
     93 		dmt->init = &dm_target_mirror_init;
     94 		dmt->table = &dm_target_mirror_table;
     95 		dmt->strategy = &dm_target_mirror_strategy;
     96 		dmt->sync = &dm_target_mirror_sync;
     97 		dmt->destroy = &dm_target_mirror_destroy;
     98 		//dmt->upcall = &dm_target_mirror_upcall;
     99 
    100 		r = dm_target_insert(dmt);
    101 
    102 		break;
    103 
    104 	case MODULE_CMD_FINI:
    105 		r = dm_target_rem("mirror");
    106 		break;
    107 
    108 	case MODULE_CMD_STAT:
    109 		return ENOTTY;
    110 
    111 	default:
    112 		return ENOTTY;
    113 	}
    114 
    115 	return r;
    116 }
    117 #endif
    118 
    119 /*
    120  * Init function called from dm_table_load_ioctl.
    121  * start length mirror log_type #logargs logarg1 ... logargN #devs device1 offset1 ... deviceN offsetN
    122  * 0 52428800 mirror clustered_disk 4 253:2 1024 UUID block_on_error 3 253:3 0 253:4 0 253:5 0
    123  */
    124 int
    125 dm_target_mirror_init(dm_table_entry_t *table_en, int argc, char **argv)
    126 {
    127 
    128 	printf("Mirror target init function called!!\n");
    129 
    130 	table_en->target_config = NULL;
    131 
    132 	return ENOSYS;
    133 }
    134 
    135 /* Table routine called to get params string. */
    136 char *
    137 dm_target_mirror_table(void *target_config)
    138 {
    139 
    140 	return NULL;
    141 }
    142 
    143 /* Strategy routine called from dm_strategy. */
    144 int
    145 dm_target_mirror_strategy(dm_table_entry_t *table_en, struct buf *bp)
    146 {
    147 
    148 	bp->b_error = EIO;
    149 	bp->b_resid = 0;
    150 
    151 	biodone(bp);
    152 
    153 	return 0;
    154 }
    155 
    156 /* Sync underlying disk caches. */
    157 int
    158 dm_target_mirror_sync(dm_table_entry_t *table_en)
    159 {
    160 
    161 	return 0;
    162 }
    163 
    164 /* Doesn't do anything here. */
    165 int
    166 dm_target_mirror_destroy(dm_table_entry_t *table_en)
    167 {
    168 
    169 	/* Unbusy target so we can unload it */
    170 	dm_target_unbusy(table_en->target);
    171 
    172 	return 0;
    173 }
    174 
    175 #if 0
    176 /* Unsupported for this target. */
    177 int
    178 dm_target_mirror_upcall(dm_table_entry_t *table_en, struct buf *bp)
    179 {
    180 
    181 	return 0;
    182 }
    183 #endif
    184