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device-mapper.c revision 1.62
      1 /*        $NetBSD: device-mapper.c,v 1.62 2021/05/07 09:54:43 hannken Exp $ */
      2 
      3 /*
      4  * Copyright (c) 2010 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  * I want to say thank you to all people who helped me with this project.
     34  */
     35 
     36 #include <sys/types.h>
     37 #include <sys/param.h>
     38 #include <sys/buf.h>
     39 #include <sys/conf.h>
     40 #include <sys/device.h>
     41 #include <sys/dkio.h>
     42 #include <sys/disk.h>
     43 #include <sys/disklabel.h>
     44 #include <sys/ioctl.h>
     45 #include <sys/ioccom.h>
     46 #include <sys/kmem.h>
     47 #include <sys/kauth.h>
     48 
     49 #include "netbsd-dm.h"
     50 #include "dm.h"
     51 #include "ioconf.h"
     52 
     53 static dev_type_open(dmopen);
     54 static dev_type_close(dmclose);
     55 static dev_type_read(dmread);
     56 static dev_type_write(dmwrite);
     57 static dev_type_ioctl(dmioctl);
     58 static dev_type_strategy(dmstrategy);
     59 static dev_type_size(dmsize);
     60 
     61 /* attach and detach routines */
     62 #ifdef _MODULE
     63 static int dmdestroy(void);
     64 #endif
     65 
     66 static void dm_doinit(void);
     67 
     68 static int dm_cmd_to_fun(prop_dictionary_t);
     69 static int disk_ioctl_switch(dev_t, unsigned long, void *);
     70 static void dmminphys(struct buf *);
     71 
     72 /* CF attach/detach functions used for power management */
     73 static int dm_detach(device_t, int);
     74 static void dm_attach(device_t, device_t, void *);
     75 static int dm_match(device_t, cfdata_t, void *);
     76 
     77 /* ***Variable-definitions*** */
     78 const struct bdevsw dm_bdevsw = {
     79 	.d_open = dmopen,
     80 	.d_close = dmclose,
     81 	.d_strategy = dmstrategy,
     82 	.d_ioctl = dmioctl,
     83 	.d_dump = nodump,
     84 	.d_psize = dmsize,
     85 	.d_discard = nodiscard,
     86 	.d_flag = D_DISK | D_MPSAFE
     87 };
     88 
     89 const struct cdevsw dm_cdevsw = {
     90 	.d_open = dmopen,
     91 	.d_close = dmclose,
     92 	.d_read = dmread,
     93 	.d_write = dmwrite,
     94 	.d_ioctl = dmioctl,
     95 	.d_stop = nostop,
     96 	.d_tty = notty,
     97 	.d_poll = nopoll,
     98 	.d_mmap = nommap,
     99 	.d_kqfilter = nokqfilter,
    100 	.d_discard = nodiscard,
    101 	.d_flag = D_DISK | D_MPSAFE
    102 };
    103 
    104 const struct dkdriver dmdkdriver = {
    105 	.d_strategy = dmstrategy
    106 };
    107 
    108 CFATTACH_DECL3_NEW(dm, 0,
    109      dm_match, dm_attach, dm_detach, NULL, NULL, NULL,
    110      DVF_DETACH_SHUTDOWN);
    111 
    112 /*
    113  * This structure is used to translate command sent to kernel driver in
    114  * <key>command</key>
    115  * <value></value>
    116  * to function which I can call, and if the command is allowed for
    117  * non-superusers.
    118  */
    119 /*
    120  * This array is used to translate cmd to function pointer.
    121  *
    122  * Interface between libdevmapper and lvm2tools uses different
    123  * names for one IOCTL call because libdevmapper do another thing
    124  * then. When I run "info" or "mknodes" libdevmapper will send same
    125  * ioctl to kernel but will do another things in userspace.
    126  *
    127  */
    128 static const struct cmd_function {
    129 	const char *cmd;
    130 	int  (*fn)(prop_dictionary_t);
    131 	int  allowed;
    132 } cmd_fn[] = {
    133 	{ .cmd = "version", .fn = NULL,                   .allowed = 1 },
    134 	{ .cmd = "targets", .fn = dm_list_versions_ioctl, .allowed = 1 },
    135 	{ .cmd = "create",  .fn = dm_dev_create_ioctl,    .allowed = 0 },
    136 	{ .cmd = "info",    .fn = dm_dev_status_ioctl,    .allowed = 1 },
    137 	{ .cmd = "mknodes", .fn = dm_dev_status_ioctl,    .allowed = 1 },
    138 	{ .cmd = "names",   .fn = dm_dev_list_ioctl,      .allowed = 1 },
    139 	{ .cmd = "suspend", .fn = dm_dev_suspend_ioctl,   .allowed = 0 },
    140 	{ .cmd = "remove",  .fn = dm_dev_remove_ioctl,    .allowed = 0 },
    141 	{ .cmd = "rename",  .fn = dm_dev_rename_ioctl,    .allowed = 0 },
    142 	{ .cmd = "resume",  .fn = dm_dev_resume_ioctl,    .allowed = 0 },
    143 	{ .cmd = "clear",   .fn = dm_table_clear_ioctl,   .allowed = 0 },
    144 	{ .cmd = "deps",    .fn = dm_table_deps_ioctl,    .allowed = 1 },
    145 	{ .cmd = "reload",  .fn = dm_table_load_ioctl,    .allowed = 0 },
    146 	{ .cmd = "status",  .fn = dm_table_status_ioctl,  .allowed = 1 },
    147 	{ .cmd = "table",   .fn = dm_table_status_ioctl,  .allowed = 1 },
    148 	{ .cmd = NULL,      .fn = NULL,                   .allowed = 0 },
    149 };
    150 
    151 #ifdef _MODULE
    152 #include <sys/module.h>
    153 
    154 /* Autoconf defines */
    155 CFDRIVER_DECL(dm, DV_DISK, NULL);
    156 
    157 MODULE(MODULE_CLASS_DRIVER, dm, "dk_subr");
    158 
    159 /* New module handle routine */
    160 static int
    161 dm_modcmd(modcmd_t cmd, void *arg)
    162 {
    163 #ifdef _MODULE
    164 	int error;
    165 	devmajor_t bmajor, cmajor;
    166 
    167 	error = 0;
    168 	bmajor = -1;
    169 	cmajor = -1;
    170 
    171 	switch (cmd) {
    172 	case MODULE_CMD_INIT:
    173 		error = config_cfdriver_attach(&dm_cd);
    174 		if (error)
    175 			break;
    176 
    177 		error = config_cfattach_attach(dm_cd.cd_name, &dm_ca);
    178 		if (error) {
    179 			aprint_error("%s: unable to register cfattach\n",
    180 			    dm_cd.cd_name);
    181 			return error;
    182 		}
    183 
    184 		error = devsw_attach(dm_cd.cd_name, &dm_bdevsw, &bmajor,
    185 		    &dm_cdevsw, &cmajor);
    186 		if (error == EEXIST)
    187 			error = 0;
    188 		if (error) {
    189 			config_cfattach_detach(dm_cd.cd_name, &dm_ca);
    190 			config_cfdriver_detach(&dm_cd);
    191 			break;
    192 		}
    193 		dm_doinit();
    194 		break;
    195 	case MODULE_CMD_FINI:
    196 		/*
    197 		 * Disable unloading of dm module if there are any devices
    198 		 * defined in driver. This is probably too strong we need
    199 		 * to disable auto-unload only if there is mounted dm device
    200 		 * present.
    201 		 */
    202 		if (dm_dev_counter > 0)
    203 			return EBUSY;
    204 		/* race window here */
    205 
    206 		error = dmdestroy();
    207 		if (error)
    208 			break;
    209 
    210 		config_cfdriver_detach(&dm_cd);
    211 
    212 		devsw_detach(&dm_bdevsw, &dm_cdevsw);
    213 		break;
    214 	case MODULE_CMD_STAT:
    215 		return ENOTTY;
    216 	default:
    217 		return ENOTTY;
    218 	}
    219 
    220 	return error;
    221 #else
    222 	return ENOTTY;
    223 #endif
    224 }
    225 #endif /* _MODULE */
    226 
    227 /*
    228  * dm_match:
    229  *
    230  *	Autoconfiguration match function for pseudo-device glue.
    231  */
    232 static int
    233 dm_match(device_t parent, cfdata_t match, void *aux)
    234 {
    235 
    236 	/* Pseudo-device; always present. */
    237 	return 1;
    238 }
    239 
    240 /*
    241  * dm_attach:
    242  *
    243  *	Autoconfiguration attach function for pseudo-device glue.
    244  */
    245 static void
    246 dm_attach(device_t parent, device_t self, void *aux)
    247 {
    248 
    249 	if (!pmf_device_register(self, NULL, NULL))
    250 		aprint_error_dev(self, "couldn't establish power handler\n");
    251 }
    252 
    253 /*
    254  * dm_detach:
    255  *
    256  *	Autoconfiguration detach function for pseudo-device glue.
    257  * This routine is called by dm_ioctl::dm_dev_remove_ioctl and by autoconf to
    258  * remove devices created in device-mapper.
    259  */
    260 static int
    261 dm_detach(device_t self, int flags)
    262 {
    263 	bool busy;
    264 	dm_dev_t *dmv;
    265 
    266 	dmv = dm_dev_lookup(NULL, NULL, device_unit(self));
    267 	mutex_enter(&dmv->diskp->dk_openlock);
    268 	busy = (dmv->diskp->dk_openmask != 0 && (flags & DETACH_FORCE) == 0);
    269 	mutex_exit(&dmv->diskp->dk_openlock);
    270 	dm_dev_unbusy(dmv);
    271 	if (busy)
    272 		return EBUSY;
    273 
    274 	pmf_device_deregister(self);
    275 
    276 	/* Detach device from global device list */
    277 	if ((dmv = dm_dev_detach(self)) == NULL)
    278 		return ENOENT;
    279 
    280 	/* Destroy active table first.  */
    281 	dm_table_destroy(&dmv->table_head, DM_TABLE_ACTIVE);
    282 
    283 	/* Destroy inactive table if exits, too. */
    284 	dm_table_destroy(&dmv->table_head, DM_TABLE_INACTIVE);
    285 
    286 	dm_table_head_destroy(&dmv->table_head);
    287 
    288 	/* Destroy disk device structure */
    289 	disk_detach(dmv->diskp);
    290 	disk_destroy(dmv->diskp);
    291 
    292 	/* Destroy device */
    293 	dm_dev_free(dmv);
    294 
    295 	/* Decrement device counter After removing device */
    296 	atomic_dec_32(&dm_dev_counter);
    297 
    298 	return 0;
    299 }
    300 
    301 static void
    302 dm_doinit(void)
    303 {
    304 
    305 	dm_target_init();
    306 	dm_dev_init();
    307 	dm_pdev_init();
    308 }
    309 
    310 /* attach routine */
    311 void
    312 dmattach(int n)
    313 {
    314 	int error;
    315 
    316 	error = config_cfattach_attach(dm_cd.cd_name, &dm_ca);
    317 	if (error)
    318 		aprint_error("%s: unable to register cfattach\n",
    319 		    dm_cd.cd_name);
    320 	else
    321 		dm_doinit();
    322 }
    323 
    324 #ifdef _MODULE
    325 /* Destroy routine */
    326 static int
    327 dmdestroy(void)
    328 {
    329 	int error;
    330 
    331 	error = config_cfattach_detach(dm_cd.cd_name, &dm_ca);
    332 	if (error)
    333 		return error;
    334 
    335 	dm_dev_destroy();
    336 	dm_pdev_destroy();
    337 	dm_target_destroy();
    338 
    339 	return 0;
    340 }
    341 #endif /* _MODULE */
    342 
    343 static int
    344 dmopen(dev_t dev, int flags, int mode, struct lwp *l)
    345 {
    346 	dm_dev_t *dmv;
    347 	struct disk *dk;
    348 
    349 	dmv = dm_dev_lookup(NULL, NULL, minor(dev));
    350 	if (dmv) {
    351 		dk = dmv->diskp;
    352 		mutex_enter(&dk->dk_openlock);
    353 		switch (mode) {
    354 		case S_IFCHR:
    355 			dk->dk_copenmask |= 1;
    356 			break;
    357 		case S_IFBLK:
    358 			dk->dk_bopenmask |= 1;
    359 			break;
    360 		}
    361 		dk->dk_openmask = dk->dk_copenmask | dk->dk_bopenmask;
    362 		mutex_exit(&dk->dk_openlock);
    363 		dm_dev_unbusy(dmv);
    364 	}
    365 
    366 	aprint_debug("dm open routine called %" PRIu32 "\n", minor(dev));
    367 	return 0;
    368 }
    369 
    370 static int
    371 dmclose(dev_t dev, int flags, int mode, struct lwp *l)
    372 {
    373 	dm_dev_t *dmv;
    374 	struct disk *dk;
    375 
    376 	aprint_debug("dm close routine called %" PRIu32 "\n", minor(dev));
    377 
    378 	dmv = dm_dev_lookup(NULL, NULL, minor(dev));
    379 	if (dmv) {
    380 		dk = dmv->diskp;
    381 		mutex_enter(&dk->dk_openlock);
    382 		switch (mode) {
    383 		case S_IFCHR:
    384 			dk->dk_copenmask &= ~1;
    385 			break;
    386 		case S_IFBLK:
    387 			dk->dk_bopenmask &= ~1;
    388 			break;
    389 		}
    390 		dk->dk_openmask = dk->dk_copenmask | dk->dk_bopenmask;
    391 		mutex_exit(&dk->dk_openlock);
    392 		dm_dev_unbusy(dmv);
    393 	}
    394 	return 0;
    395 }
    396 
    397 
    398 static int
    399 dmioctl(dev_t dev, const u_long cmd, void *data, int flag, struct lwp *l)
    400 {
    401 	int r;
    402 	prop_dictionary_t dm_dict_in;
    403 
    404 	aprint_debug("dmioctl called\n");
    405 	KASSERT(data != NULL);
    406 
    407 	if ((r = disk_ioctl_switch(dev, cmd, data)) == ENOTTY) {
    408 		struct plistref *pref = (struct plistref *)data;
    409 
    410 		switch(cmd) {
    411 		case NETBSD_DM_IOCTL:
    412 			aprint_debug("dm NETBSD_DM_IOCTL called\n");
    413 			break;
    414 		default:
    415 			aprint_debug("dm unknown ioctl called\n");
    416 			return ENOTTY;
    417 			break; /* NOT REACHED */
    418 		}
    419 
    420 		if ((r = prop_dictionary_copyin_ioctl(pref, cmd, &dm_dict_in))
    421 		    != 0)
    422 			return r;
    423 
    424 		if ((r = dm_check_version(dm_dict_in)) != 0)
    425 			goto cleanup_exit;
    426 
    427 		/* run ioctl routine */
    428 		if ((r = dm_cmd_to_fun(dm_dict_in)) != 0)
    429 			goto cleanup_exit;
    430 
    431 cleanup_exit:
    432 		r = prop_dictionary_copyout_ioctl(pref, cmd, dm_dict_in);
    433 		prop_object_release(dm_dict_in);
    434 	}
    435 
    436 	return r;
    437 }
    438 
    439 /*
    440  * Translate command sent from libdevmapper to func.
    441  */
    442 static int
    443 dm_cmd_to_fun(prop_dictionary_t dm_dict)
    444 {
    445 	int i, r;
    446 	prop_string_t command;
    447 
    448 	if ((command = prop_dictionary_get(dm_dict, DM_IOCTL_COMMAND)) == NULL)
    449 		return EINVAL;
    450 
    451 	for (i = 0; cmd_fn[i].cmd != NULL; i++)
    452 		if (prop_string_equals_string(command, cmd_fn[i].cmd))
    453 			break;
    454 
    455 	if (!cmd_fn[i].allowed &&
    456 	    (r = kauth_authorize_system(kauth_cred_get(),
    457 	    KAUTH_SYSTEM_DEVMAPPER, 0, NULL, NULL, NULL)) != 0)
    458 		return r;
    459 
    460 	if (cmd_fn[i].cmd == NULL)
    461 		return EINVAL;
    462 
    463 	aprint_debug("ioctl %s called %p\n", cmd_fn[i].cmd, cmd_fn[i].fn);
    464 	if (cmd_fn[i].fn == NULL)
    465 		return 0;
    466 
    467 	return cmd_fn[i].fn(dm_dict);
    468 }
    469 
    470 /*
    471  * Check for disk specific ioctls.
    472  */
    473 static int
    474 disk_ioctl_switch(dev_t dev, unsigned long cmd, void *data)
    475 {
    476 	dm_dev_t *dmv;
    477 
    478 	/* disk ioctls make sense only on block devices */
    479 	if (minor(dev) == 0)
    480 		return ENOTTY;
    481 
    482 	switch(cmd) {
    483 	case DIOCGWEDGEINFO:
    484 	{
    485 		struct dkwedge_info *dkw = (void *) data;
    486 
    487 		if ((dmv = dm_dev_lookup(NULL, NULL, minor(dev))) == NULL)
    488 			return ENODEV;
    489 
    490 		aprint_debug("DIOCGWEDGEINFO ioctl called\n");
    491 
    492 		strlcpy(dkw->dkw_devname, dmv->name, 16);
    493 		strlcpy(dkw->dkw_wname, dmv->name, DM_NAME_LEN);
    494 		strlcpy(dkw->dkw_parent, dmv->name, 16);
    495 
    496 		dkw->dkw_offset = 0;
    497 		dm_table_disksize(&dmv->table_head, &dkw->dkw_size, NULL);
    498 		strcpy(dkw->dkw_ptype, DKW_PTYPE_FFS);
    499 
    500 		dm_dev_unbusy(dmv);
    501 		break;
    502 	}
    503 	case DIOCGDISKINFO:
    504 	{
    505 		struct plistref *pref = (struct plistref *) data;
    506 
    507 		if ((dmv = dm_dev_lookup(NULL, NULL, minor(dev))) == NULL)
    508 			return ENODEV;
    509 
    510 		aprint_debug("DIOCGDISKINFO ioctl called\n");
    511 
    512 		if (dmv->diskp->dk_info == NULL) {
    513 			dm_dev_unbusy(dmv);
    514 			return ENOTSUP;
    515 		} else
    516 			prop_dictionary_copyout_ioctl(pref, cmd,
    517 			    dmv->diskp->dk_info);
    518 
    519 		dm_dev_unbusy(dmv);
    520 		break;
    521 	}
    522 	case DIOCCACHESYNC:
    523 	{
    524 		dm_table_entry_t *table_en;
    525 		dm_table_t *tbl;
    526 
    527 		if ((dmv = dm_dev_lookup(NULL, NULL, minor(dev))) == NULL)
    528 			return ENODEV;
    529 
    530 		aprint_debug("DIOCCACHESYNC ioctl called\n");
    531 
    532 		/* Select active table */
    533 		tbl = dm_table_get_entry(&dmv->table_head, DM_TABLE_ACTIVE);
    534 
    535 		/*
    536 		 * Call sync target routine for all table entries. Target sync
    537 		 * routine basically call DIOCCACHESYNC on underlying devices.
    538 		 */
    539 		SLIST_FOREACH(table_en, tbl, next)
    540 			if (table_en->target->sync)
    541 				table_en->target->sync(table_en);
    542 		dm_table_release(&dmv->table_head, DM_TABLE_ACTIVE);
    543 		dm_dev_unbusy(dmv);
    544 		break;
    545 	}
    546 	case DIOCGSECTORSIZE:
    547 	{
    548 		unsigned int secsize, *valp = data;
    549 
    550 		if ((dmv = dm_dev_lookup(NULL, NULL, minor(dev))) == NULL)
    551 			return ENODEV;
    552 
    553 		aprint_debug("DIOCGSECTORSIZE ioctl called\n");
    554 
    555 		dm_table_disksize(&dmv->table_head, NULL, &secsize);
    556 		*valp = secsize;
    557 
    558 		dm_dev_unbusy(dmv);
    559 		break;
    560 	}
    561 	case DIOCGMEDIASIZE:
    562 	{
    563 		off_t *valp = data;
    564 		uint64_t numsec;
    565 
    566 		if ((dmv = dm_dev_lookup(NULL, NULL, minor(dev))) == NULL)
    567 			return ENODEV;
    568 
    569 		aprint_debug("DIOCGMEDIASIZE ioctl called\n");
    570 
    571 		dm_table_disksize(&dmv->table_head, &numsec, NULL);
    572 		*valp = numsec;
    573 
    574 		dm_dev_unbusy(dmv);
    575 		break;
    576 	}
    577 	default:
    578 		aprint_debug("unknown disk_ioctl called\n");
    579 		return ENOTTY;
    580 		break; /* NOT REACHED */
    581 	}
    582 
    583 	return 0;
    584 }
    585 
    586 /*
    587  * Do all IO operations on dm logical devices.
    588  */
    589 static void
    590 dmstrategy(struct buf *bp)
    591 {
    592 	dm_dev_t *dmv;
    593 	dm_table_t *tbl;
    594 	dm_table_entry_t *table_en;
    595 	struct buf *nestbuf;
    596 
    597 	uint64_t buf_start, buf_len, issued_len;
    598 	uint64_t table_start, table_end;
    599 	uint64_t start, end;
    600 
    601 	buf_start = bp->b_blkno * DEV_BSIZE;
    602 	buf_len = bp->b_bcount;
    603 
    604 	table_end = 0;
    605 	issued_len = 0;
    606 
    607 	if ((dmv = dm_dev_lookup(NULL, NULL, minor(bp->b_dev))) == NULL) {
    608 		bp->b_error = EIO;
    609 		bp->b_resid = bp->b_bcount;
    610 		biodone(bp);
    611 		return;
    612 	}
    613 
    614 	if (bounds_check_with_mediasize(bp, DEV_BSIZE,
    615 	    dm_table_size(&dmv->table_head)) <= 0) {
    616 		dm_dev_unbusy(dmv);
    617 		bp->b_resid = bp->b_bcount;
    618 		biodone(bp);
    619 		return;
    620 	}
    621 
    622 	/*
    623 	 * disk(9) is part of device structure and it can't be used without
    624 	 * mutual exclusion, use diskp_mtx until it will be fixed.
    625 	 */
    626 	mutex_enter(&dmv->diskp_mtx);
    627 	disk_busy(dmv->diskp);
    628 	mutex_exit(&dmv->diskp_mtx);
    629 
    630 	/* Select active table */
    631 	tbl = dm_table_get_entry(&dmv->table_head, DM_TABLE_ACTIVE);
    632 
    633 	 /* Nested buffers count down to zero therefore I have
    634 	    to set bp->b_resid to maximal value. */
    635 	bp->b_resid = bp->b_bcount;
    636 
    637 	/*
    638 	 * Find out what tables I want to select.
    639 	 */
    640 	SLIST_FOREACH(table_en, tbl, next) {
    641 		/* I need number of bytes not blocks. */
    642 		table_start = table_en->start * DEV_BSIZE;
    643 		/*
    644 		 * I have to sub 1 from table_en->length to prevent
    645 		 * off by one error
    646 		 */
    647 		table_end = table_start + table_en->length * DEV_BSIZE;
    648 		start = MAX(table_start, buf_start);
    649 		end = MIN(table_end, buf_start + buf_len);
    650 
    651 		aprint_debug("----------------------------------------\n");
    652 		aprint_debug("table_start %010" PRIu64", table_end %010"
    653 		    PRIu64 "\n", table_start, table_end);
    654 		aprint_debug("buf_start %010" PRIu64", buf_len %010"
    655 		    PRIu64"\n", buf_start, buf_len);
    656 		aprint_debug("start-buf_start %010"PRIu64", end %010"
    657 		    PRIu64"\n", start - buf_start, end);
    658 		aprint_debug("start %010" PRIu64", end %010"
    659                     PRIu64"\n", start, end);
    660 		aprint_debug("----------------------------------------\n");
    661 
    662 		if (start < end) {
    663 			/* create nested buffer  */
    664 			nestbuf = getiobuf(NULL, true);
    665 			nestiobuf_setup(bp, nestbuf, start - buf_start,
    666 			    end - start);
    667 			issued_len += end - start;
    668 			/* I need number of blocks. */
    669 			nestbuf->b_blkno = (start - table_start) / DEV_BSIZE;
    670 			table_en->target->strategy(table_en, nestbuf);
    671 		}
    672 	}
    673 
    674 	if (issued_len < buf_len)
    675 		nestiobuf_done(bp, buf_len - issued_len, EINVAL);
    676 
    677 	mutex_enter(&dmv->diskp_mtx);
    678 	disk_unbusy(dmv->diskp, buf_len, bp ? (bp->b_flags & B_READ) : 0);
    679 	mutex_exit(&dmv->diskp_mtx);
    680 
    681 	dm_table_release(&dmv->table_head, DM_TABLE_ACTIVE);
    682 	dm_dev_unbusy(dmv);
    683 }
    684 
    685 
    686 static int
    687 dmread(dev_t dev, struct uio *uio, int flag)
    688 {
    689 
    690 	return physio(dmstrategy, NULL, dev, B_READ, dmminphys, uio);
    691 }
    692 
    693 static int
    694 dmwrite(dev_t dev, struct uio *uio, int flag)
    695 {
    696 
    697 	return physio(dmstrategy, NULL, dev, B_WRITE, dmminphys, uio);
    698 }
    699 
    700 static int
    701 dmsize(dev_t dev)
    702 {
    703 	dm_dev_t *dmv;
    704 	uint64_t size;
    705 
    706 	if ((dmv = dm_dev_lookup(NULL, NULL, minor(dev))) == NULL)
    707 		return -ENOENT;
    708 
    709 	size = dm_table_size(&dmv->table_head);
    710 	dm_dev_unbusy(dmv);
    711 
    712 	return size;
    713 }
    714 
    715 static void
    716 dmminphys(struct buf *bp)
    717 {
    718 
    719 	bp->b_bcount = MIN(bp->b_bcount, MAXPHYS);
    720 }
    721 
    722 void
    723 dmgetproperties(struct disk *disk, dm_table_head_t *head)
    724 {
    725 	uint64_t numsec;
    726 	unsigned int secsize;
    727 	struct disk_geom *dg;
    728 
    729 	dm_table_disksize(head, &numsec, &secsize);
    730 
    731 	dg = &disk->dk_geom;
    732 
    733 	memset(dg, 0, sizeof(*dg));
    734 	dg->dg_secperunit = numsec;
    735 	dg->dg_secsize = secsize;
    736 	dg->dg_nsectors = 32;
    737 	dg->dg_ntracks = 64;
    738 
    739 	disk_set_info(NULL, disk, "ESDI");
    740 }
    741 
    742 /*
    743  * Transform char s to uint64_t offset number.
    744  */
    745 uint64_t
    746 atoi64(const char *s)
    747 {
    748 	uint64_t n;
    749 	n = 0;
    750 
    751 	while (*s != '\0') {
    752 		if (!isdigit(*s))
    753 			break;
    754 
    755 		n = (10 * n) + (*s - '0');
    756 		s++;
    757 	}
    758 
    759 	return n;
    760 }
    761