xref: /titanic_41/usr/src/uts/common/io/lvm/md/md.c (revision 890e8ff10cfc85bc7d33064a9a30c3e8477b4813)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  */
25 
26 #pragma ident	"%Z%%M%	%I%	%E% SMI"
27 
28 /*
29  * Md - is the meta-disk driver.   It sits below the UFS file system
30  * but above the 'real' disk drivers, xy, id, sd etc.
31  *
32  * To the UFS software, md looks like a normal driver, since it has
33  * the normal kinds of entries in the bdevsw and cdevsw arrays. So
34  * UFS accesses md in the usual ways.  In particular, the strategy
35  * routine, mdstrategy(), gets called by fbiwrite(), ufs_getapage(),
36  * and ufs_writelbn().
37  *
38  * Md maintains an array of minor devices (meta-partitions).   Each
39  * meta partition stands for a matrix of real partitions, in rows
40  * which are not necessarily of equal length.	Md maintains a table,
41  * with one entry for each meta-partition,  which lists the rows and
42  * columns of actual partitions, and the job of the strategy routine
43  * is to translate from the meta-partition device and block numbers
44  * known to UFS into the actual partitions' device and block numbers.
45  *
46  * See below, in mdstrategy(), mdreal(), and mddone() for details of
47  * this translation.
48  */
49 
50 /*
51  * Driver for Virtual Disk.
52  */
53 
54 #include <sys/user.h>
55 #include <sys/sysmacros.h>
56 #include <sys/conf.h>
57 #include <sys/stat.h>
58 #include <sys/errno.h>
59 #include <sys/param.h>
60 #include <sys/systm.h>
61 #include <sys/file.h>
62 #include <sys/open.h>
63 #include <sys/dkio.h>
64 #include <sys/vtoc.h>
65 #include <sys/cmn_err.h>
66 #include <sys/ddi.h>
67 #include <sys/sunddi.h>
68 #include <sys/debug.h>
69 #include <sys/utsname.h>
70 #include <sys/lvm/mdvar.h>
71 #include <sys/lvm/md_names.h>
72 #include <sys/lvm/md_mddb.h>
73 #include <sys/lvm/md_sp.h>
74 #include <sys/types.h>
75 #include <sys/kmem.h>
76 #include <sys/cladm.h>
77 #include <sys/priv_names.h>
78 
79 #ifndef	lint
80 char 		_depends_on[] = "strmod/rpcmod";
81 #endif	/* lint */
82 int		md_init_debug	= 0;	/* module binding debug */
83 
84 /*
85  * Tunable to turn off the failfast behavior.
86  */
87 int		md_ff_disable = 0;
88 
89 /*
90  * dynamically allocated list of non FF driver names - needs to
91  * be freed when md is detached.
92  */
93 char	**non_ff_drivers = NULL;
94 
95 md_krwlock_t	md_unit_array_rw;	/* protects all unit arrays */
96 md_krwlock_t	nm_lock;		/* protects all the name spaces */
97 
98 md_resync_t	md_cpr_resync;
99 
100 extern char	svm_bootpath[];
101 #define	SVM_PSEUDO_STR	"/pseudo/md@0:"
102 
103 #define		VERSION_LENGTH	6
104 #define		VERSION		"1.0"
105 
106 /*
107  * Keep track of possible 'orphan' entries in the name space
108  */
109 int		*md_nm_snarfed = NULL;
110 
111 /*
112  * Global tunable giving the percentage of free space left in replica during
113  * conversion of non-devid style replica to devid style replica.
114  */
115 int		md_conv_perc = MDDB_DEVID_CONV_PERC;
116 
117 #ifdef	DEBUG
118 /* debug code to verify framework exclusion guarantees */
119 int		md_in;
120 kmutex_t	md_in_mx;			/* used to md global stuff */
121 #define	IN_INIT		0x01
122 #define	IN_FINI		0x02
123 #define	IN_ATTACH	0x04
124 #define	IN_DETACH	0x08
125 #define	IN_OPEN		0x10
126 #define	MD_SET_IN(x) {						\
127 	mutex_enter(&md_in_mx);					\
128 	if (md_in)						\
129 		debug_enter("MD_SET_IN exclusion lost");	\
130 	if (md_in & x)						\
131 		debug_enter("MD_SET_IN already set");		\
132 	md_in |= x;						\
133 	mutex_exit(&md_in_mx);					\
134 }
135 
136 #define	MD_CLR_IN(x) {						\
137 	mutex_enter(&md_in_mx);					\
138 	if (md_in & ~(x))					\
139 		debug_enter("MD_CLR_IN exclusion lost");	\
140 	if (!(md_in & x))					\
141 		debug_enter("MD_CLR_IN already clr");		\
142 	md_in &= ~x;						\
143 	mutex_exit(&md_in_mx);					\
144 }
145 #else	/* DEBUG */
146 #define	MD_SET_IN(x)
147 #define	MD_CLR_IN(x)
148 #endif	/* DEBUG */
149 hrtime_t savetime1, savetime2;
150 
151 
152 /*
153  * list things protected by md_mx even if they aren't
154  * used in this file.
155  */
156 kmutex_t	md_mx;			/* used to md global stuff */
157 kcondvar_t	md_cv;			/* md_status events */
158 int		md_status = 0;		/* global status for the meta-driver */
159 int		md_num_daemons = 0;
160 int		md_ioctl_cnt = 0;
161 int		md_mtioctl_cnt = 0;	/* multithreaded ioctl cnt */
162 uint_t		md_mdelay = 10;		/* variable so can be patched */
163 
164 int		(*mdv_strategy_tstpnt)(buf_t *, int, void*);
165 
166 major_t		md_major, md_major_targ;
167 
168 unit_t		md_nunits = MD_MAXUNITS;
169 set_t		md_nsets = MD_MAXSETS;
170 int		md_nmedh = 0;
171 char		*md_med_trans_lst = NULL;
172 md_set_t	md_set[MD_MAXSETS];
173 md_set_io_t	md_set_io[MD_MAXSETS];
174 
175 md_krwlock_t	hsp_rwlp;		/* protects hot_spare_interface */
176 md_krwlock_t	ni_rwlp;		/* protects notify_interface */
177 md_ops_t	**md_ops;
178 ddi_modhandle_t	*md_mods;
179 md_ops_t	*md_opslist;
180 clock_t		md_hz;
181 md_event_queue_t	*md_event_queue = NULL;
182 
183 int		md_in_upgrade;
184 int		md_keep_repl_state;
185 int		md_devid_destroy;
186 
187 /* for sending messages thru a door to userland */
188 door_handle_t	mdmn_door_handle = NULL;
189 int		mdmn_door_did = -1;
190 
191 dev_info_t		*md_devinfo = NULL;
192 
193 md_mn_nodeid_t	md_mn_mynode_id = ~0u;	/* My node id (for multi-node sets) */
194 
195 static	uint_t		md_ocnt[OTYPCNT];
196 
197 static int		mdinfo(dev_info_t *, ddi_info_cmd_t, void *, void **);
198 static int		mdattach(dev_info_t *, ddi_attach_cmd_t);
199 static int		mddetach(dev_info_t *, ddi_detach_cmd_t);
200 static int		mdopen(dev_t *, int, int, cred_t *);
201 static int		mdclose(dev_t, int, int, cred_t *);
202 static int		mddump(dev_t, caddr_t, daddr_t, int);
203 static int		mdread(dev_t, struct uio *, cred_t *);
204 static int		mdwrite(dev_t, struct uio *, cred_t *);
205 static int		mdaread(dev_t, struct aio_req *, cred_t *);
206 static int		mdawrite(dev_t, struct aio_req *, cred_t *);
207 static int		mdioctl(dev_t, int, intptr_t, int, cred_t *, int *);
208 static int		mdprop_op(dev_t, dev_info_t *,
209 				ddi_prop_op_t, int, char *, caddr_t, int *);
210 
211 static struct cb_ops md_cb_ops = {
212 	mdopen,			/* open */
213 	mdclose,		/* close */
214 	mdstrategy,		/* strategy */
215 				/* print routine -- none yet */
216 	(int(*)(dev_t, char *))nulldev,
217 	mddump,			/* dump */
218 	mdread,			/* read */
219 	mdwrite,		/* write */
220 	mdioctl,		/* ioctl */
221 				/* devmap */
222 	(int(*)(dev_t, devmap_cookie_t, offset_t, size_t, size_t *,
223 			uint_t))nodev,
224 				/* mmap */
225 	(int(*)(dev_t, off_t, int))nodev,
226 				/* segmap */
227 	(int(*)(dev_t, off_t, struct as *, caddr_t *, off_t, unsigned,
228 		unsigned, unsigned, cred_t *))nodev,
229 	nochpoll,		/* poll */
230 	mdprop_op,		/* prop_op */
231 	0,			/* streamtab */
232 	(D_64BIT|D_MP|D_NEW),	/* driver compatibility flag */
233 	CB_REV,			/* cb_ops version */
234 	mdaread,		/* aread */
235 	mdawrite,		/* awrite */
236 };
237 
238 static struct dev_ops md_devops = {
239 	DEVO_REV,		/* dev_ops version */
240 	0,			/* device reference count */
241 	mdinfo,			/* info routine */
242 	nulldev,		/* identify routine */
243 	nulldev,		/* probe - not defined */
244 	mdattach,		/* attach routine */
245 	mddetach,		/* detach routine */
246 	nodev,			/* reset - not defined */
247 	&md_cb_ops,		/* driver operations */
248 	NULL,			/* bus operations */
249 	nodev			/* power management */
250 };
251 
252 /*
253  * loadable module wrapper
254  */
255 #include <sys/modctl.h>
256 
257 static struct modldrv modldrv = {
258 	&mod_driverops,			/* type of module -- a pseudodriver */
259 	"Solaris Volume Manager base module %I%", /* name of the module */
260 	&md_devops,			/* driver ops */
261 };
262 
263 static struct modlinkage modlinkage = {
264 	MODREV_1,
265 	(void *)&modldrv,
266 	NULL
267 };
268 
269 
270 /* md_medd.c */
271 extern	void	med_init(void);
272 extern	void	med_fini(void);
273 extern  void	md_devid_cleanup(set_t, uint_t);
274 
275 /* md_names.c */
276 extern void			*lookup_entry(struct nm_next_hdr *, set_t,
277 					side_t, mdkey_t, md_dev64_t, int);
278 extern struct nm_next_hdr	*get_first_record(set_t, int, int);
279 extern int			remove_entry(struct nm_next_hdr *,
280 					side_t, mdkey_t, int);
281 
282 int		md_maxphys	= 0;	/* maximum io size in bytes */
283 #define		MD_MAXBCOUNT	(1024 * 1024)
284 unsigned	md_maxbcount	= 0;	/* maximum physio size in bytes */
285 
286 /* allocate/free dynamic space associated with driver globals */
287 void
288 md_global_alloc_free(int alloc)
289 {
290 	set_t	s;
291 
292 	if (alloc) {
293 		/* initialize driver global locks */
294 		cv_init(&md_cv, NULL, CV_DEFAULT, NULL);
295 		mutex_init(&md_mx, NULL, MUTEX_DEFAULT, NULL);
296 		rw_init(&md_unit_array_rw.lock, NULL, RW_DEFAULT, NULL);
297 		rw_init(&nm_lock.lock, NULL, RW_DEFAULT, NULL);
298 		rw_init(&ni_rwlp.lock, NULL, RW_DRIVER, NULL);
299 		rw_init(&hsp_rwlp.lock, NULL, RW_DRIVER, NULL);
300 		mutex_init(&md_cpr_resync.md_resync_mutex, NULL,
301 			MUTEX_DEFAULT, NULL);
302 
303 		/* initialize per set driver global locks */
304 		for (s = 0; s < MD_MAXSETS; s++) {
305 			/* initialize per set driver globals locks */
306 			mutex_init(&md_set[s].s_dbmx,
307 			    NULL, MUTEX_DEFAULT, NULL);
308 			mutex_init(&md_set_io[s].md_io_mx,
309 			    NULL, MUTEX_DEFAULT, NULL);
310 			cv_init(&md_set_io[s].md_io_cv,
311 			    NULL, CV_DEFAULT, NULL);
312 		}
313 	} else {
314 		/* destroy per set driver global locks */
315 		for (s = 0; s < MD_MAXSETS; s++) {
316 			cv_destroy(&md_set_io[s].md_io_cv);
317 			mutex_destroy(&md_set_io[s].md_io_mx);
318 			mutex_destroy(&md_set[s].s_dbmx);
319 		}
320 
321 		/* destroy driver global locks */
322 		mutex_destroy(&md_cpr_resync.md_resync_mutex);
323 		rw_destroy(&hsp_rwlp.lock);
324 		rw_destroy(&ni_rwlp.lock);
325 		rw_destroy(&nm_lock.lock);
326 		rw_destroy(&md_unit_array_rw.lock);
327 		mutex_destroy(&md_mx);
328 		cv_destroy(&md_cv);
329 	}
330 }
331 
332 int
333 _init(void)
334 {
335 	set_t	s;
336 	int	err;
337 
338 	MD_SET_IN(IN_INIT);
339 
340 	/* allocate dynamic space associated with driver globals */
341 	md_global_alloc_free(1);
342 
343 	/* initialize driver globals */
344 	md_major = ddi_name_to_major("md");
345 	md_hz = drv_usectohz(NUM_USEC_IN_SEC);
346 
347 	/* initialize tunable globals */
348 	if (md_maxphys == 0)		/* maximum io size in bytes */
349 		md_maxphys = maxphys;
350 	if (md_maxbcount == 0)		/* maximum physio size in bytes */
351 		md_maxbcount = MD_MAXBCOUNT;
352 
353 	/* initialize per set driver globals */
354 	for (s = 0; s < MD_MAXSETS; s++)
355 		md_set_io[s].io_state = MD_SET_ACTIVE;
356 
357 	/*
358 	 * NOTE: the framework does not currently guarantee exclusion
359 	 * between _init and attach after calling mod_install.
360 	 */
361 	MD_CLR_IN(IN_INIT);
362 	if ((err = mod_install(&modlinkage))) {
363 		MD_SET_IN(IN_INIT);
364 		md_global_alloc_free(0);	/* free dynamic space */
365 		MD_CLR_IN(IN_INIT);
366 	}
367 	return (err);
368 }
369 
370 int
371 _fini(void)
372 {
373 	int	err;
374 
375 	/*
376 	 * NOTE: the framework currently does not guarantee exclusion
377 	 * with attach until after mod_remove returns 0.
378 	 */
379 	if ((err = mod_remove(&modlinkage)))
380 		return (err);
381 
382 	MD_SET_IN(IN_FINI);
383 	md_global_alloc_free(0);	/* free dynamic space */
384 	MD_CLR_IN(IN_FINI);
385 	return (err);
386 }
387 
388 int
389 _info(struct modinfo *modinfop)
390 {
391 	return (mod_info(&modlinkage, modinfop));
392 }
393 
394 /* ARGSUSED */
395 static int
396 mdattach(dev_info_t *dip, ddi_attach_cmd_t cmd)
397 {
398 	int	len;
399 	unit_t	i;
400 	size_t	sz;
401 	char	ver[VERSION_LENGTH];
402 	char	**maj_str_array;
403 	char	*str, *str2;
404 
405 	MD_SET_IN(IN_ATTACH);
406 	md_in_upgrade = 0;
407 	md_keep_repl_state = 0;
408 	md_devid_destroy = 0;
409 
410 	if (cmd != DDI_ATTACH) {
411 		MD_CLR_IN(IN_ATTACH);
412 		return (DDI_FAILURE);
413 	}
414 
415 	if (md_devinfo != NULL) {
416 		MD_CLR_IN(IN_ATTACH);
417 		return (DDI_FAILURE);
418 	}
419 
420 	mddb_init();
421 
422 	if (md_start_daemons(TRUE)) {
423 		MD_CLR_IN(IN_ATTACH);
424 		mddb_unload();		/* undo mddb_init() allocations */
425 		return (DDI_FAILURE);
426 	}
427 
428 	/* clear the halted state */
429 	md_clr_status(MD_GBL_HALTED);
430 
431 	/* see if the diagnostic switch is on */
432 	if (ddi_prop_get_int(DDI_DEV_T_ANY, dip,
433 	    DDI_PROP_DONTPASS, "md_init_debug", 0))
434 		md_init_debug++;
435 
436 	/* see if the failfast disable switch is on */
437 	if (ddi_prop_get_int(DDI_DEV_T_ANY, dip,
438 	    DDI_PROP_DONTPASS, "md_ff_disable", 0))
439 		md_ff_disable++;
440 
441 	/* try and get the md_nmedh property */
442 	md_nmedh = ddi_prop_get_int(DDI_DEV_T_ANY, dip,
443 	    DDI_PROP_DONTPASS, "md_nmedh", MED_DEF_HOSTS);
444 	if ((md_nmedh <= 0) || (md_nmedh > MED_MAX_HOSTS))
445 		md_nmedh = MED_DEF_HOSTS;
446 
447 	/* try and get the md_med_trans_lst property */
448 	len = 0;
449 	if (ddi_prop_op(DDI_DEV_T_ANY, dip, PROP_LEN,
450 	    0, "md_med_trans_lst", NULL, &len) != DDI_PROP_SUCCESS ||
451 	    len == 0) {
452 		md_med_trans_lst = md_strdup("tcp");
453 	} else {
454 		md_med_trans_lst = kmem_zalloc((size_t)len, KM_SLEEP);
455 		if (ddi_prop_op(DDI_DEV_T_ANY, dip, PROP_LEN_AND_VAL_BUF,
456 		    0, "md_med_trans_lst", md_med_trans_lst, &len) !=
457 		    DDI_PROP_SUCCESS) {
458 			kmem_free(md_med_trans_lst, (size_t)len);
459 			md_med_trans_lst = md_strdup("tcp");
460 		}
461 	}
462 
463 	/* try and get the md_xlate property */
464 	/* Should we only do this if upgrade? */
465 	len = sizeof (char) * 5;
466 	if (ddi_prop_op(DDI_DEV_T_ANY, dip, PROP_LEN_AND_VAL_BUF,
467 	    0, "md_xlate_ver", ver, &len) == DDI_PROP_SUCCESS) {
468 		if (strcmp(ver, VERSION) == 0) {
469 			len = 0;
470 			if (ddi_prop_op(DDI_DEV_T_ANY, dip,
471 			    PROP_LEN_AND_VAL_ALLOC, 0, "md_xlate",
472 			    (caddr_t)&md_tuple_table, &len) !=
473 			    DDI_PROP_SUCCESS) {
474 				if (md_init_debug)
475 					cmn_err(CE_WARN,
476 					    "md_xlate ddi_prop_op failed");
477 				goto attach_failure;
478 			} else {
479 				md_tuple_length =
480 				    len/(2 * ((int)sizeof (dev32_t)));
481 				md_in_upgrade = 1;
482 			}
483 
484 			/* Get target's name to major table */
485 			if (ddi_prop_lookup_string_array(DDI_DEV_T_ANY,
486 			    dip, DDI_PROP_DONTPASS,
487 			    "md_targ_nm_table", &maj_str_array,
488 			    &md_majortab_len) != DDI_PROP_SUCCESS) {
489 				md_majortab_len = 0;
490 				if (md_init_debug)
491 				    cmn_err(CE_WARN, "md_targ_nm_table "
492 				    "ddi_prop_lookup_string_array failed");
493 				goto attach_failure;
494 			}
495 
496 			md_major_tuple_table =
497 			    (struct md_xlate_major_table *)
498 			    kmem_zalloc(md_majortab_len *
499 			    sizeof (struct md_xlate_major_table), KM_SLEEP);
500 
501 			for (i = 0; i < md_majortab_len; i++) {
502 				/* Getting major name */
503 				str = strchr(maj_str_array[i], ' ');
504 				if (str == NULL)
505 					continue;
506 				*str = '\0';
507 				md_major_tuple_table[i].drv_name =
508 				    md_strdup(maj_str_array[i]);
509 
510 				/* Simplified atoi to get major number */
511 				str2 = str + 1;
512 				md_major_tuple_table[i].targ_maj = 0;
513 				while ((*str2 >= '0') && (*str2 <= '9')) {
514 				    md_major_tuple_table[i].targ_maj *= 10;
515 				    md_major_tuple_table[i].targ_maj +=
516 					*str2++ - '0';
517 				}
518 				*str = ' ';
519 			}
520 			ddi_prop_free((void *)maj_str_array);
521 		} else {
522 			if (md_init_debug)
523 				cmn_err(CE_WARN, "md_xlate_ver is incorrect");
524 			goto attach_failure;
525 		}
526 	}
527 
528 	/*
529 	 * Check for properties:
530 	 * 	md_keep_repl_state and md_devid_destroy
531 	 * and set globals if these exist.
532 	 */
533 	md_keep_repl_state = ddi_getprop(DDI_DEV_T_ANY, dip,
534 				    0, "md_keep_repl_state", 0);
535 
536 	md_devid_destroy = ddi_getprop(DDI_DEV_T_ANY, dip,
537 				    0, "md_devid_destroy", 0);
538 
539 	if (MD_UPGRADE)
540 		md_major_targ = md_targ_name_to_major("md");
541 	else
542 		md_major_targ = 0;
543 
544 	/* alloc md_ops and md_mods struct */
545 	md_ops = (md_ops_t **)kmem_zalloc(
546 	    sizeof (md_ops_t *) * MD_NOPS, KM_SLEEP);
547 	md_mods = (ddi_modhandle_t *)kmem_zalloc(
548 	    sizeof (ddi_modhandle_t) * MD_NOPS, KM_SLEEP);
549 
550 	/* allocate admin device node */
551 	if (ddi_create_priv_minor_node(dip, "admin", S_IFCHR,
552 	    MD_ADM_MINOR, DDI_PSEUDO, 0, NULL, PRIV_SYS_CONFIG, 0640))
553 		goto attach_failure;
554 
555 	if (ddi_prop_create(DDI_DEV_T_NONE, dip, DDI_PROP_CANSLEEP,
556 	    DDI_KERNEL_IOCTL, NULL, 0) != DDI_SUCCESS)
557 		goto attach_failure;
558 
559 	if (ddi_prop_update_int(DDI_DEV_T_NONE, dip,
560 	    "ddi-abrwrite-supported", 1) != DDI_SUCCESS)
561 		goto attach_failure;
562 
563 	/* these could have been cleared by a detach */
564 	md_nunits = MD_MAXUNITS;
565 	md_nsets = MD_MAXSETS;
566 
567 	sz = sizeof (void *) * MD_MAXUNITS;
568 	if (md_set[0].s_un == NULL)
569 		md_set[0].s_un = kmem_zalloc(sz, KM_SLEEP);
570 	if (md_set[0].s_ui == NULL)
571 		md_set[0].s_ui = kmem_zalloc(sz, KM_SLEEP);
572 
573 	md_devinfo = dip;
574 
575 	/*
576 	 * Only allocate device node for root mirror metadevice.
577 	 * Don't pre-allocate unnecessary device nodes (thus slowing down a
578 	 * boot when we attach).
579 	 * We can't read the mddbs in attach.  The mddbs will be read
580 	 * by metainit during the boot process when it is doing the
581 	 * auto-take processing and any other minor nodes will be
582 	 * allocated at that point.
583 	 *
584 	 * There are two scenarios to be aware of here:
585 	 * 1) when we are booting from a mirrored root we need the root
586 	 *    metadevice to exist very early (during vfs_mountroot processing)
587 	 * 2) we need all of the nodes to be created so that any mnttab entries
588 	 *    will succeed (handled by metainit reading the mddb during boot).
589 	 */
590 	if (strncmp(SVM_PSEUDO_STR, svm_bootpath, sizeof (SVM_PSEUDO_STR) - 1)
591 	    == 0) {
592 		char *p;
593 		int mnum = 0;
594 
595 		/*
596 		 * The svm_bootpath string looks something like
597 		 * /pseudo/md@0:0,150,blk where 150 is the minor number
598 		 * in this example so we need to set the pointer p onto
599 		 * the first digit of the minor number and convert it
600 		 * from ascii.
601 		 */
602 		for (p = svm_bootpath + sizeof (SVM_PSEUDO_STR) + 1;
603 		    *p >= '0' && *p <= '9'; p++) {
604 			mnum *= 10;
605 			mnum += *p - '0';
606 		}
607 
608 		if (md_create_minor_node(0, mnum)) {
609 			kmem_free(md_set[0].s_un, sz);
610 			kmem_free(md_set[0].s_ui, sz);
611 			goto attach_failure;
612 		}
613 	}
614 
615 	med_init();
616 
617 	MD_CLR_IN(IN_ATTACH);
618 	return (DDI_SUCCESS);
619 
620 attach_failure:
621 	/*
622 	 * Use our own detach routine to toss any stuff we allocated above.
623 	 * NOTE: detach will call md_halt to free the mddb_init allocations.
624 	 */
625 	MD_CLR_IN(IN_ATTACH);
626 	if (mddetach(dip, DDI_DETACH) != DDI_SUCCESS)
627 		cmn_err(CE_WARN, "detach from attach failed");
628 	return (DDI_FAILURE);
629 }
630 
631 /* ARGSUSED */
632 static int
633 mddetach(dev_info_t *dip, ddi_detach_cmd_t cmd)
634 {
635 	extern int	check_active_locators();
636 	set_t		s;
637 	size_t		sz;
638 	int		len;
639 
640 	MD_SET_IN(IN_DETACH);
641 
642 	/* check command */
643 	if (cmd != DDI_DETACH) {
644 		MD_CLR_IN(IN_DETACH);
645 		return (DDI_FAILURE);
646 	}
647 
648 	/*
649 	 * if we have not already halted yet we have no active config
650 	 * then automatically initiate a halt so we can detach.
651 	 */
652 	if (!(md_get_status() & MD_GBL_HALTED)) {
653 		if (check_active_locators() == 0) {
654 			/*
655 			 * NOTE: a successful md_halt will have done the
656 			 * mddb_unload to free allocations done in mddb_init
657 			 */
658 			if (md_halt(MD_NO_GBL_LOCKS_HELD)) {
659 				cmn_err(CE_NOTE, "md:detach: "
660 				    "Could not halt Solaris Volume Manager");
661 				MD_CLR_IN(IN_DETACH);
662 				return (DDI_FAILURE);
663 			}
664 		}
665 
666 		/* fail detach if we have not halted */
667 		if (!(md_get_status() & MD_GBL_HALTED)) {
668 			MD_CLR_IN(IN_DETACH);
669 			return (DDI_FAILURE);
670 		}
671 	}
672 
673 	/* must be in halted state, this will be cleared on next attach */
674 	ASSERT(md_get_status() & MD_GBL_HALTED);
675 
676 	/* cleanup attach allocations and initializations */
677 	md_major_targ = 0;
678 
679 	sz = sizeof (void *) * md_nunits;
680 	for (s = 0; s < md_nsets; s++) {
681 		if (md_set[s].s_un != NULL) {
682 			kmem_free(md_set[s].s_un, sz);
683 			md_set[s].s_un = NULL;
684 		}
685 
686 		if (md_set[s].s_ui != NULL) {
687 			kmem_free(md_set[s].s_ui, sz);
688 			md_set[s].s_ui = NULL;
689 		}
690 	}
691 	md_nunits = 0;
692 	md_nsets = 0;
693 	md_nmedh = 0;
694 
695 	if (non_ff_drivers != NULL) {
696 		int	i;
697 
698 		for (i = 0; non_ff_drivers[i] != NULL; i++)
699 		    kmem_free(non_ff_drivers[i], strlen(non_ff_drivers[i]) + 1);
700 
701 		kmem_free(non_ff_drivers, 2 * sizeof (char *));
702 		non_ff_drivers = NULL;
703 	}
704 
705 	if (md_med_trans_lst != NULL) {
706 		kmem_free(md_med_trans_lst, strlen(md_med_trans_lst) + 1);
707 		md_med_trans_lst = NULL;
708 	}
709 
710 	if (md_mods != NULL) {
711 		kmem_free(md_mods, sizeof (ddi_modhandle_t) * MD_NOPS);
712 		md_mods = NULL;
713 	}
714 
715 	if (md_ops != NULL) {
716 		kmem_free(md_ops, sizeof (md_ops_t *) * MD_NOPS);
717 		md_ops = NULL;
718 	}
719 
720 	if (MD_UPGRADE) {
721 		len = md_tuple_length * (2 * ((int)sizeof (dev32_t)));
722 		md_in_upgrade = 0;
723 		md_xlate_free(len);
724 		md_majortab_free();
725 	}
726 
727 	/*
728 	 * Undo what we did in mdattach, freeing resources
729 	 * and removing things we installed.  The system
730 	 * framework guarantees we are not active with this devinfo
731 	 * node in any other entry points at this time.
732 	 */
733 	ddi_prop_remove_all(dip);
734 	ddi_remove_minor_node(dip, NULL);
735 
736 	med_fini();
737 	md_devinfo = NULL;
738 
739 	MD_CLR_IN(IN_DETACH);
740 	return (DDI_SUCCESS);
741 }
742 
743 
744 /*
745  * Given the device number return the devinfo pointer
746  * given to md via md_attach
747  */
748 /*ARGSUSED*/
749 static int
750 mdinfo(dev_info_t *dip, ddi_info_cmd_t infocmd, void *arg, void **result)
751 {
752 	int		error = DDI_FAILURE;
753 
754 	switch (infocmd) {
755 	case DDI_INFO_DEVT2DEVINFO:
756 		if (md_devinfo) {
757 			*result = (void *)md_devinfo;
758 			error = DDI_SUCCESS;
759 		}
760 		break;
761 
762 	case DDI_INFO_DEVT2INSTANCE:
763 		*result = (void *)0;
764 		error = DDI_SUCCESS;
765 		break;
766 	}
767 	return (error);
768 }
769 
770 /*
771  * property operation routine.  return the number of blocks for the partition
772  * in question or forward the request to the property facilities.
773  */
774 static int
775 mdprop_op(
776 	dev_t dev,		/* device number associated with device */
777 	dev_info_t *dip,	/* device info struct for this device */
778 	ddi_prop_op_t prop_op,	/* property operator */
779 	int mod_flags,		/* property flags */
780 	char *name,		/* name of property */
781 	caddr_t valuep,		/* where to put property value */
782 	int *lengthp)		/* put length of property here */
783 {
784 	minor_t		mnum;
785 	set_t		setno;
786 	md_unit_t	*un;
787 	mdi_unit_t	*ui;
788 	uint64_t	nblocks64;
789 
790 	/*
791 	 * Our dynamic properties are all device specific and size oriented.
792 	 * Requests issued under conditions where size is valid are passed
793 	 * to ddi_prop_op_nblocks with the size information, otherwise the
794 	 * request is passed to ddi_prop_op. Make sure that the minor device
795 	 * is a valid part of the Virtual Disk subsystem.
796 	 */
797 	mnum = getminor(dev);
798 	setno = MD_MIN2SET(mnum);
799 	if ((dev == DDI_DEV_T_ANY) || (mnum == MD_ADM_MINOR) ||
800 	    (setno >= md_nsets) || (MD_MIN2UNIT(mnum) >= md_nunits)) {
801 pass:		return (ddi_prop_op(dev, dip, prop_op, mod_flags,
802 		    name, valuep, lengthp));
803 	} else {
804 		rw_enter(&md_unit_array_rw.lock, RW_READER);
805 		if (((md_get_setstatus(setno) & MD_SET_SNARFED) == 0) ||
806 		    ((ui = MDI_UNIT(mnum)) == NULL)) {
807 			rw_exit(&md_unit_array_rw.lock);
808 			goto pass;
809 		}
810 
811 		/* get nblocks value */
812 		un = (md_unit_t *)md_unit_readerlock(ui);
813 		nblocks64 = un->c.un_total_blocks;
814 		md_unit_readerexit(ui);
815 		rw_exit(&md_unit_array_rw.lock);
816 
817 		return (ddi_prop_op_nblocks(dev, dip, prop_op, mod_flags,
818 		    name, valuep, lengthp, nblocks64));
819 	}
820 
821 }
822 
823 static void
824 snarf_user_data(set_t setno)
825 {
826 	mddb_recid_t		recid;
827 	mddb_recstatus_t	status;
828 
829 	recid = mddb_makerecid(setno, 0);
830 	while ((recid = mddb_getnextrec(recid, MDDB_USER, 0)) > 0) {
831 		if (mddb_getrecprivate(recid) & MD_PRV_GOTIT)
832 			continue;
833 
834 		status = mddb_getrecstatus(recid);
835 		if (status == MDDB_STALE)
836 			continue;
837 
838 		if (status == MDDB_NODATA) {
839 			mddb_setrecprivate(recid, MD_PRV_PENDDEL);
840 			continue;
841 		}
842 
843 		ASSERT(status == MDDB_OK);
844 
845 		mddb_setrecprivate(recid, MD_PRV_GOTIT);
846 	}
847 }
848 
849 static void
850 md_print_block_usage(mddb_set_t *s, uint_t blks)
851 {
852 	uint_t		ib;
853 	int		li;
854 	mddb_mb_ic_t	*mbip;
855 	uint_t		max_blk_needed;
856 	mddb_lb_t	*lbp;
857 	mddb_sidelocator_t	*slp;
858 	int		drv_index;
859 	md_splitname	sn;
860 	char		*name;
861 	char		*suffix;
862 	size_t		prefixlen;
863 	size_t		suffixlen;
864 	int		alloc_sz;
865 
866 
867 	max_blk_needed = s->s_totalblkcnt - s->s_freeblkcnt + blks;
868 
869 
870 	cmn_err(CE_WARN, "Blocks in Metadevice State Database: %d\n"
871 		"            Additional Blocks Needed:            %d\n\n"
872 		"            Increase size of following replicas for\n"
873 		"            device relocatability by deleting listed\n"
874 		"            replica and re-adding replica with\n"
875 		"            increased size (see metadb(1M)):\n"
876 		"                Replica                   Increase By",
877 		s->s_totalblkcnt, (blks - s->s_freeblkcnt));
878 
879 	lbp = s->s_lbp;
880 
881 	for (li = 0; li < lbp->lb_loccnt; li++) {
882 		if (lbp->lb_locators[li].l_flags & MDDB_F_DELETED)
883 			continue;
884 		ib = 0;
885 		for (mbip = s->s_mbiarray[li]; mbip != NULL;
886 		    mbip = mbip->mbi_next) {
887 			ib += (uint_t)mbip->mbi_mddb_mb.mb_blkcnt;
888 		}
889 		if (ib == 0)
890 			continue;
891 		if (ib < max_blk_needed) {
892 			slp = &lbp->lb_sidelocators[s->s_sideno][li];
893 			drv_index = slp->l_drvnm_index;
894 			mddb_locatorblock2splitname(s->s_lnp, li, s->s_sideno,
895 				&sn);
896 			prefixlen = SPN_PREFIX(&sn).pre_len;
897 			suffixlen = SPN_SUFFIX(&sn).suf_len;
898 			alloc_sz = (int)(prefixlen + suffixlen + 2);
899 			name = (char *)kmem_alloc(alloc_sz, KM_SLEEP);
900 			(void) strncpy(name, SPN_PREFIX(&sn).pre_data,
901 			    prefixlen);
902 			name[prefixlen] = '/';
903 			suffix = name + (prefixlen + 1);
904 			(void) strncpy(suffix, SPN_SUFFIX(&sn).suf_data,
905 			    suffixlen);
906 			name[prefixlen + suffixlen + 1] = '\0';
907 			cmn_err(CE_WARN,
908 				"  %s (%s:%d:%d)   %d blocks",
909 				name, lbp->lb_drvnm[drv_index].dn_data,
910 				slp->l_mnum, lbp->lb_locators[li].l_blkno,
911 				(max_blk_needed - ib));
912 			kmem_free(name, alloc_sz);
913 		}
914 	}
915 }
916 
917 /*
918  * md_create_minor_node:
919  *	Create the minor device for the given set and un_self_id.
920  *
921  * Input:
922  *	setno	- set number
923  *	mnum	- selfID of unit
924  *
925  * Output:
926  *	None.
927  *
928  * Returns 0 for success, 1 for failure.
929  *
930  * Side-effects:
931  *	None.
932  */
933 int
934 md_create_minor_node(set_t setno, minor_t mnum)
935 {
936 	char		name[20];
937 
938 	/* Check for valid arguments */
939 	if (setno >= MD_MAXSETS || MD_MIN2UNIT(mnum) >= MD_MAXUNITS)
940 		return (1);
941 
942 	(void) snprintf(name, 20, "%u,%u,blk",
943 		(unsigned)setno, (unsigned)MD_MIN2UNIT(mnum));
944 
945 	if (ddi_create_minor_node(md_devinfo, name, S_IFBLK,
946 	    MD_MKMIN(setno, mnum), DDI_PSEUDO, 0))
947 		return (1);
948 
949 	(void) snprintf(name, 20, "%u,%u,raw",
950 		(unsigned)setno, (unsigned)MD_MIN2UNIT(mnum));
951 
952 	if (ddi_create_minor_node(md_devinfo, name, S_IFCHR,
953 	    MD_MKMIN(setno, mnum), DDI_PSEUDO, 0))
954 		return (1);
955 
956 	return (0);
957 }
958 
959 /*
960  * For a given key check if it is an orphaned record.
961  * The following conditions are used to determine an orphan.
962  * 1. The device associated with that key is not a metadevice.
963  * 2. If DEVID_STYLE then the physical device does not have a device Id
964  * associated with it.
965  *
966  * If a key does not have an entry in the devid namespace it could be
967  * a device that does not support device ids. Hence the record is not
968  * deleted.
969  */
970 
971 static int
972 md_verify_orphaned_record(set_t setno, mdkey_t key)
973 {
974 	md_dev64_t	odev; /* orphaned dev */
975 	mddb_set_t	*s;
976 	side_t		side = 0;
977 	struct nm_next_hdr	*did_nh = NULL;
978 
979 	s = (mddb_set_t *)md_set[setno].s_db;
980 	if ((did_nh = get_first_record(setno, 1,  (NM_DEVID | NM_NOTSHARED)))
981 	    == NULL)
982 		return (0);
983 	/*
984 	 * If devid style is set then get the dev_t using MD_NOTRUST_DEVT
985 	 */
986 	if (s->s_lbp->lb_flags & MDDB_DEVID_STYLE) {
987 		odev = md_getdevnum(setno, side, key, MD_NOTRUST_DEVT);
988 		if ((odev == NODEV64) || (md_getmajor(odev) == md_major))
989 			return (0);
990 		if (lookup_entry(did_nh, setno, side, key, odev, NM_DEVID) ==
991 									NULL)
992 			return (1);
993 	}
994 	return (0);
995 }
996 
997 int
998 md_snarf_db_set(set_t setno, md_error_t *ep)
999 {
1000 	int			err = 0;
1001 	int			i;
1002 	mddb_recid_t		recid;
1003 	mddb_type_t		drvrid;
1004 	mddb_recstatus_t	status;
1005 	md_ops_t		*ops;
1006 	uint_t			privat;
1007 	mddb_set_t		*s;
1008 	uint_t			cvt_blks;
1009 	struct nm_next_hdr	*nh;
1010 	mdkey_t			key = MD_KEYWILD;
1011 	side_t			side = 0;
1012 	int			size;
1013 	int			devid_flag;
1014 	int			retval;
1015 	uint_t			un;
1016 	int			un_next_set = 0;
1017 
1018 	md_haltsnarf_enter(setno);
1019 
1020 	mutex_enter(&md_mx);
1021 	if (md_set[setno].s_status & MD_SET_SNARFED) {
1022 		mutex_exit(&md_mx);
1023 		md_haltsnarf_exit(setno);
1024 		return (0);
1025 	}
1026 	mutex_exit(&md_mx);
1027 
1028 	if (! (md_get_status() & MD_GBL_DAEMONS_LIVE)) {
1029 		if (md_start_daemons(TRUE)) {
1030 			if (ep != NULL)
1031 				(void) mdsyserror(ep, ENXIO);
1032 			err = -1;
1033 			goto out;
1034 		}
1035 	}
1036 
1037 
1038 	/*
1039 	 * Load the devid name space if it exists
1040 	 */
1041 	(void) md_load_namespace(setno, NULL, NM_DEVID);
1042 	if (!md_load_namespace(setno, ep, 0L)) {
1043 		/*
1044 		 * Unload the devid namespace
1045 		 */
1046 		(void) md_unload_namespace(setno, NM_DEVID);
1047 		err = -1;
1048 		goto out;
1049 	}
1050 
1051 	/*
1052 	 * If replica is in non-devid state, convert if:
1053 	 * 	- not in probe during upgrade (md_keep_repl_state = 0)
1054 	 * 	- enough space available in replica
1055 	 *	- local set
1056 	 *	- not a multi-node diskset
1057 	 *	- clustering is not present (for non-local set)
1058 	 */
1059 	s = (mddb_set_t *)md_set[setno].s_db;
1060 	devid_flag = 0;
1061 	if (!(s->s_lbp->lb_flags & MDDB_DEVID_STYLE) && !md_keep_repl_state)
1062 		devid_flag = 1;
1063 	if (cluster_bootflags & CLUSTER_CONFIGURED)
1064 		if (setno != MD_LOCAL_SET)
1065 			devid_flag = 0;
1066 	if (MD_MNSET_SETNO(setno))
1067 		devid_flag = 0;
1068 	if ((md_devid_destroy == 1) && (md_keep_repl_state == 1))
1069 		devid_flag = 0;
1070 
1071 	/*
1072 	 * if we weren't devid style before and md_keep_repl_state=1
1073 	 * we need to stay non-devid
1074 	 */
1075 	if ((md_keep_repl_state == 1) &&
1076 	    ((s->s_lbp->lb_flags & MDDB_DEVID_STYLE) == 0))
1077 		devid_flag = 0;
1078 	if (devid_flag) {
1079 		/*
1080 		 * Determine number of free blocks needed to convert
1081 		 * entire replica to device id format - locator blocks
1082 		 * and namespace.
1083 		 */
1084 		cvt_blks = 0;
1085 		if (mddb_lb_did_convert(s, 0, &cvt_blks) != 0) {
1086 			if (ep != NULL)
1087 				(void) mdsyserror(ep, EIO);
1088 			err = -1;
1089 			goto out;
1090 
1091 		}
1092 		cvt_blks += md_nm_did_chkspace(setno);
1093 
1094 		/* add MDDB_DEVID_CONV_PERC% */
1095 		if ((md_conv_perc > 0) && (md_conv_perc <= 100)) {
1096 			cvt_blks = cvt_blks * (100 + md_conv_perc) / 100;
1097 		}
1098 
1099 		if (cvt_blks <= s->s_freeblkcnt) {
1100 			if (mddb_lb_did_convert(s, 1, &cvt_blks) != 0) {
1101 				if (ep != NULL)
1102 					(void) mdsyserror(ep, EIO);
1103 				err = -1;
1104 				goto out;
1105 			}
1106 
1107 		} else {
1108 			/*
1109 			 * Print message that replica can't be converted for
1110 			 * lack of space.   No failure - just continue to
1111 			 * run without device ids.
1112 			 */
1113 			cmn_err(CE_WARN,
1114 			    "Unable to add Solaris Volume Manager device "
1115 			    "relocation data.\n"
1116 			    "          To use device relocation feature:\n"
1117 			    "          - Increase size of listed replicas\n"
1118 			    "          - Reboot");
1119 			md_print_block_usage(s, cvt_blks);
1120 			cmn_err(CE_WARN,
1121 			    "Loading set without device relocation data.\n"
1122 			    "          Solaris Volume Manager disk movement "
1123 			    "not tracked in local set.");
1124 		}
1125 	}
1126 
1127 	/*
1128 	 * go through and load any modules referenced in
1129 	 * data base
1130 	 */
1131 	recid = mddb_makerecid(setno, 0);
1132 	while ((recid = mddb_getnextrec(recid, MDDB_ALL, 0)) > 0) {
1133 		status = mddb_getrecstatus(recid);
1134 		if (status == MDDB_STALE) {
1135 			if (! (md_get_setstatus(setno) & MD_SET_STALE)) {
1136 				md_set_setstatus(setno, MD_SET_STALE);
1137 				cmn_err(CE_WARN,
1138 				    "md: state database is stale");
1139 			}
1140 		} else if (status == MDDB_NODATA) {
1141 			mddb_setrecprivate(recid, MD_PRV_PENDDEL);
1142 			continue;
1143 		}
1144 		drvrid = mddb_getrectype1(recid);
1145 		if (drvrid < MDDB_FIRST_MODID)
1146 			continue;
1147 		if (md_loadsubmod(setno, md_getshared_name(setno, drvrid),
1148 		    drvrid) < 0) {
1149 			cmn_err(CE_NOTE, "md: could not load misc/%s",
1150 				md_getshared_name(setno, drvrid));
1151 		}
1152 	}
1153 
1154 	if (recid < 0)
1155 		goto out;
1156 
1157 	snarf_user_data(setno);
1158 
1159 	/*
1160 	 * Initialize the md_nm_snarfed array
1161 	 * this array is indexed by the key and
1162 	 * is set by md_getdevnum during the snarf time
1163 	 */
1164 	if ((nh = get_first_record(setno, 0, NM_NOTSHARED)) != NULL) {
1165 		size = (int)((((struct nm_rec_hdr *)nh->nmn_record)->
1166 		    r_next_key) * (sizeof (int)));
1167 		md_nm_snarfed = (int *)kmem_zalloc(size, KM_SLEEP);
1168 	}
1169 
1170 	/*
1171 	 * go through and snarf until nothing gets added
1172 	 */
1173 	do {
1174 		i = 0;
1175 		for (ops = md_opslist; ops != NULL; ops = ops->md_next) {
1176 			if (ops->md_snarf != NULL) {
1177 				retval = ops->md_snarf(MD_SNARF_DOIT, setno);
1178 				if (retval == -1) {
1179 					err = -1;
1180 					/* Don't know the failed unit */
1181 					(void) mdmderror(ep, MDE_RR_ALLOC_ERROR,
1182 					    0);
1183 					(void) md_halt_set(setno, MD_HALT_ALL);
1184 					(void) mddb_unload_set(setno);
1185 					md_haltsnarf_exit(setno);
1186 					return (err);
1187 				} else {
1188 					i += retval;
1189 				}
1190 			}
1191 		}
1192 	} while (i);
1193 
1194 	/*
1195 	 * Set the first available slot and availability
1196 	 */
1197 	md_set[setno].s_un_avail = 0;
1198 	for (un = 0; un < MD_MAXUNITS; un++) {
1199 		if (md_set[setno].s_un[un] != NULL) {
1200 			continue;
1201 		} else {
1202 			if (!un_next_set) {
1203 				md_set[setno].s_un_next = un;
1204 				un_next_set = 1;
1205 			}
1206 			md_set[setno].s_un_avail++;
1207 		}
1208 	}
1209 
1210 	md_set_setstatus(setno, MD_SET_SNARFED);
1211 
1212 	recid = mddb_makerecid(setno, 0);
1213 	while ((recid = mddb_getnextrec(recid, MDDB_ALL, 0)) > 0) {
1214 		privat = mddb_getrecprivate(recid);
1215 		if (privat & MD_PRV_COMMIT) {
1216 			if (mddb_commitrec(recid)) {
1217 				if (!(md_get_setstatus(setno) & MD_SET_STALE)) {
1218 					md_set_setstatus(setno, MD_SET_STALE);
1219 					cmn_err(CE_WARN,
1220 					    "md: state database is stale");
1221 				}
1222 			}
1223 			mddb_setrecprivate(recid, MD_PRV_GOTIT);
1224 		}
1225 	}
1226 
1227 	/* Deletes must happen after all the commits */
1228 	recid = mddb_makerecid(setno, 0);
1229 	while ((recid = mddb_getnextrec(recid, MDDB_ALL, 0)) > 0) {
1230 		privat = mddb_getrecprivate(recid);
1231 		if (privat & MD_PRV_DELETE) {
1232 			if (mddb_deleterec(recid)) {
1233 				if (!(md_get_setstatus(setno) & MD_SET_STALE)) {
1234 					md_set_setstatus(setno, MD_SET_STALE);
1235 					cmn_err(CE_WARN,
1236 					    "md: state database is stale");
1237 				}
1238 				mddb_setrecprivate(recid, MD_PRV_GOTIT);
1239 			}
1240 			recid = mddb_makerecid(setno, 0);
1241 		}
1242 	}
1243 
1244 	/*
1245 	 * go through and clean up records until nothing gets cleaned up.
1246 	 */
1247 	do {
1248 		i = 0;
1249 		for (ops = md_opslist; ops != NULL; ops = ops->md_next)
1250 			if (ops->md_snarf != NULL)
1251 				i += ops->md_snarf(MD_SNARF_CLEANUP, setno);
1252 	} while (i);
1253 
1254 	if (md_nm_snarfed != NULL &&
1255 	    !(md_get_setstatus(setno) & MD_SET_STALE)) {
1256 		/*
1257 		 * go thru and cleanup the namespace and the device id
1258 		 * name space
1259 		 */
1260 		for (key = 1;
1261 		    key < ((struct nm_rec_hdr *)nh->nmn_record)->r_next_key;
1262 		    key++) {
1263 			/*
1264 			 * Is the entry an 'orphan'?
1265 			 */
1266 			if (lookup_entry(nh, setno, side, key, NODEV64, 0L) !=
1267 			    NULL) {
1268 				/*
1269 				 * If the value is not set then apparently
1270 				 * it is not part of the current configuration,
1271 				 * remove it this can happen when system panic
1272 				 * between the primary name space update and
1273 				 * the device id name space update
1274 				 */
1275 				if (md_nm_snarfed[key] == 0) {
1276 					if (md_verify_orphaned_record(setno,
1277 					    key) == 1)
1278 						(void) remove_entry(nh,
1279 						    side, key, 0L);
1280 				}
1281 			}
1282 		}
1283 	}
1284 
1285 	if (md_nm_snarfed != NULL) {
1286 		/*
1287 		 * Done and free the memory
1288 		 */
1289 		kmem_free(md_nm_snarfed, size);
1290 		md_nm_snarfed = NULL;
1291 	}
1292 
1293 	if (s->s_lbp->lb_flags & MDDB_DEVID_STYLE &&
1294 	    !(md_get_setstatus(setno) & MD_SET_STALE)) {
1295 		/*
1296 		 * if the destroy flag has been set and
1297 		 * the MD_SET_DIDCLUP bit is not set in
1298 		 * the set's status field, cleanup the
1299 		 * entire device id namespace
1300 		 */
1301 		if (md_devid_destroy &&
1302 		    !(md_get_setstatus(setno) & MD_SET_DIDCLUP)) {
1303 			(void) md_devid_cleanup(setno, 1);
1304 			md_set_setstatus(setno, MD_SET_DIDCLUP);
1305 		} else
1306 			(void) md_devid_cleanup(setno, 0);
1307 	}
1308 
1309 	/*
1310 	 * clear single threading on snarf, return success or error
1311 	 */
1312 out:
1313 	md_haltsnarf_exit(setno);
1314 	return (err);
1315 }
1316 
1317 void
1318 get_minfo(struct dk_minfo *info, minor_t mnum)
1319 {
1320 	md_unit_t	*un;
1321 	mdi_unit_t	*ui;
1322 
1323 	info->dki_capacity = 0;
1324 	info->dki_lbsize = 0;
1325 	info->dki_media_type = 0;
1326 
1327 	if ((ui = MDI_UNIT(mnum)) == NULL) {
1328 		return;
1329 	}
1330 	un = (md_unit_t *)md_unit_readerlock(ui);
1331 	info->dki_capacity = un->c.un_total_blocks;
1332 	md_unit_readerexit(ui);
1333 	info->dki_lbsize = DEV_BSIZE;
1334 	info->dki_media_type = DK_UNKNOWN;
1335 }
1336 
1337 
1338 void
1339 get_info(struct dk_cinfo *info, minor_t mnum)
1340 {
1341 	/*
1342 	 * Controller Information
1343 	 */
1344 	info->dki_ctype = DKC_MD;
1345 	info->dki_cnum = ddi_get_instance(ddi_get_parent(md_devinfo));
1346 	(void) strcpy(info->dki_cname,
1347 	    ddi_get_name(ddi_get_parent(md_devinfo)));
1348 	/*
1349 	 * Unit Information
1350 	 */
1351 	info->dki_unit = mnum;
1352 	info->dki_slave = 0;
1353 	(void) strcpy(info->dki_dname, ddi_driver_name(md_devinfo));
1354 	info->dki_flags = 0;
1355 	info->dki_partition = 0;
1356 	info->dki_maxtransfer = (ushort_t)(md_maxphys / DEV_BSIZE);
1357 
1358 	/*
1359 	 * We can't get from here to there yet
1360 	 */
1361 	info->dki_addr = 0;
1362 	info->dki_space = 0;
1363 	info->dki_prio = 0;
1364 	info->dki_vec = 0;
1365 }
1366 
1367 /*
1368  * open admin device
1369  */
1370 static int
1371 mdadminopen(
1372 	int	flag,
1373 	int	otyp)
1374 {
1375 	int	err = 0;
1376 
1377 	/* single thread */
1378 	mutex_enter(&md_mx);
1379 
1380 	/* check type and flags */
1381 	if ((otyp != OTYP_CHR) && (otyp != OTYP_LYR)) {
1382 		err = EINVAL;
1383 		goto out;
1384 	}
1385 	if (((flag & FEXCL) && (md_status & MD_GBL_OPEN)) ||
1386 	    (md_status & MD_GBL_EXCL)) {
1387 		err = EBUSY;
1388 		goto out;
1389 	}
1390 
1391 	/* count and flag open */
1392 	md_ocnt[otyp]++;
1393 	md_status |= MD_GBL_OPEN;
1394 	if (flag & FEXCL)
1395 		md_status |= MD_GBL_EXCL;
1396 
1397 	/* unlock return success */
1398 out:
1399 	mutex_exit(&md_mx);
1400 	return (err);
1401 }
1402 
1403 /*
1404  * open entry point
1405  */
1406 static int
1407 mdopen(
1408 	dev_t		*dev,
1409 	int		flag,
1410 	int		otyp,
1411 	cred_t		*cred_p)
1412 {
1413 	minor_t		mnum = getminor(*dev);
1414 	unit_t		unit = MD_MIN2UNIT(mnum);
1415 	set_t		setno = MD_MIN2SET(mnum);
1416 	mdi_unit_t	*ui = NULL;
1417 	int		err = 0;
1418 	md_parent_t	parent;
1419 
1420 	/* dispatch admin device opens */
1421 	if (mnum == MD_ADM_MINOR)
1422 		return (mdadminopen(flag, otyp));
1423 
1424 	/* lock, check status */
1425 	rw_enter(&md_unit_array_rw.lock, RW_READER);
1426 
1427 tryagain:
1428 	if (md_get_status() & MD_GBL_HALTED)  {
1429 		err = ENODEV;
1430 		goto out;
1431 	}
1432 
1433 	/* check minor */
1434 	if ((setno >= md_nsets) || (unit >= md_nunits)) {
1435 		err = ENXIO;
1436 		goto out;
1437 	}
1438 
1439 	/* make sure we're snarfed */
1440 	if ((md_get_setstatus(MD_LOCAL_SET) & MD_SET_SNARFED) == 0) {
1441 		if (md_snarf_db_set(MD_LOCAL_SET, NULL) != 0) {
1442 			err = ENODEV;
1443 			goto out;
1444 		}
1445 	}
1446 	if ((md_get_setstatus(setno) & MD_SET_SNARFED) == 0) {
1447 		err = ENODEV;
1448 		goto out;
1449 	}
1450 
1451 	/* check unit */
1452 	if ((ui = MDI_UNIT(mnum)) == NULL) {
1453 		err = ENXIO;
1454 		goto out;
1455 	}
1456 
1457 	/*
1458 	 * The softpart open routine may do an I/O during the open, in
1459 	 * which case the open routine will set the OPENINPROGRESS flag
1460 	 * and drop all locks during the I/O.  If this thread sees
1461 	 * the OPENINPROGRESS flag set, if should wait until the flag
1462 	 * is reset before calling the driver's open routine.  It must
1463 	 * also revalidate the world after it grabs the unit_array lock
1464 	 * since the set may have been released or the metadevice cleared
1465 	 * during the sleep.
1466 	 */
1467 	if (MD_MNSET_SETNO(setno)) {
1468 		mutex_enter(&ui->ui_mx);
1469 		if (ui->ui_lock & MD_UL_OPENINPROGRESS) {
1470 			rw_exit(&md_unit_array_rw.lock);
1471 			cv_wait(&ui->ui_cv, &ui->ui_mx);
1472 			rw_enter(&md_unit_array_rw.lock, RW_READER);
1473 			mutex_exit(&ui->ui_mx);
1474 			goto tryagain;
1475 		}
1476 		mutex_exit(&ui->ui_mx);
1477 	}
1478 
1479 	/* Test if device is openable */
1480 	if ((ui->ui_tstate & MD_NOTOPENABLE) != 0) {
1481 		err = ENXIO;
1482 		goto out;
1483 	}
1484 
1485 	/* don't allow opens w/WRITE flag if stale */
1486 	if ((flag & FWRITE) && (md_get_setstatus(setno) & MD_SET_STALE)) {
1487 		err = EROFS;
1488 		goto out;
1489 	}
1490 
1491 	/* don't allow writes to subdevices */
1492 	parent = md_get_parent(md_expldev(*dev));
1493 	if ((flag & FWRITE) && MD_HAS_PARENT(parent)) {
1494 		err = EROFS;
1495 		goto out;
1496 	}
1497 
1498 	/* open underlying driver */
1499 	if (md_ops[ui->ui_opsindex]->md_open != NULL) {
1500 		if ((err = (*md_ops[ui->ui_opsindex]->md_open)
1501 		    (dev, flag, otyp, cred_p, 0)) != 0)
1502 			goto out;
1503 	}
1504 
1505 	/* or do it ourselves */
1506 	else {
1507 		/* single thread */
1508 		(void) md_unit_openclose_enter(ui);
1509 		err = md_unit_incopen(mnum, flag, otyp);
1510 		md_unit_openclose_exit(ui);
1511 		if (err != 0)
1512 			goto out;
1513 	}
1514 
1515 	/* unlock, return status */
1516 out:
1517 	rw_exit(&md_unit_array_rw.lock);
1518 	return (err);
1519 }
1520 
1521 /*
1522  * close admin device
1523  */
1524 static int
1525 mdadminclose(
1526 	int	otyp)
1527 {
1528 	int	i;
1529 	int	err = 0;
1530 
1531 	/* single thread */
1532 	mutex_enter(&md_mx);
1533 
1534 	/* check type and flags */
1535 	if ((otyp < 0) || (otyp >= OTYPCNT)) {
1536 		err = EINVAL;
1537 		goto out;
1538 	} else if (md_ocnt[otyp] == 0) {
1539 		err = ENXIO;
1540 		goto out;
1541 	}
1542 
1543 	/* count and flag closed */
1544 	if (otyp == OTYP_LYR)
1545 		md_ocnt[otyp]--;
1546 	else
1547 		md_ocnt[otyp] = 0;
1548 	md_status &= ~MD_GBL_OPEN;
1549 	for (i = 0; (i < OTYPCNT); ++i)
1550 		if (md_ocnt[i] != 0)
1551 			md_status |= MD_GBL_OPEN;
1552 	if (! (md_status & MD_GBL_OPEN))
1553 		md_status &= ~MD_GBL_EXCL;
1554 
1555 	/* unlock return success */
1556 out:
1557 	mutex_exit(&md_mx);
1558 	return (err);
1559 }
1560 
1561 /*
1562  * close entry point
1563  */
1564 static int
1565 mdclose(
1566 	dev_t		dev,
1567 	int		flag,
1568 	int		otyp,
1569 	cred_t		*cred_p)
1570 {
1571 	minor_t		mnum = getminor(dev);
1572 	set_t		setno = MD_MIN2SET(mnum);
1573 	unit_t		unit = MD_MIN2UNIT(mnum);
1574 	mdi_unit_t	*ui = NULL;
1575 	int		err = 0;
1576 
1577 	/* dispatch admin device closes */
1578 	if (mnum == MD_ADM_MINOR)
1579 		return (mdadminclose(otyp));
1580 
1581 	/* check minor */
1582 	if ((setno >= md_nsets) || (unit >= md_nunits) ||
1583 	    ((ui = MDI_UNIT(mnum)) == NULL)) {
1584 		err = ENXIO;
1585 		goto out;
1586 	}
1587 
1588 	/* close underlying driver */
1589 	if (md_ops[ui->ui_opsindex]->md_close != NULL) {
1590 		if ((err = (*md_ops[ui->ui_opsindex]->md_close)
1591 		    (dev, flag, otyp, cred_p, 0)) != 0)
1592 			goto out;
1593 	}
1594 
1595 	/* or do it ourselves */
1596 	else {
1597 		/* single thread */
1598 		(void) md_unit_openclose_enter(ui);
1599 		err = md_unit_decopen(mnum, otyp);
1600 		md_unit_openclose_exit(ui);
1601 		if (err != 0)
1602 			goto out;
1603 	}
1604 
1605 	/* return success */
1606 out:
1607 	return (err);
1608 }
1609 
1610 
1611 /*
1612  * This routine performs raw read operations.  It is called from the
1613  * device switch at normal priority.
1614  *
1615  * The main catch is that the *uio struct which is passed to us may
1616  * specify a read which spans two buffers, which would be contiguous
1617  * on a single partition,  but not on a striped partition. This will
1618  * be handled by mdstrategy.
1619  */
1620 /*ARGSUSED*/
1621 static int
1622 mdread(dev_t dev, struct uio *uio, cred_t *credp)
1623 {
1624 	minor_t		mnum;
1625 	mdi_unit_t	*ui;
1626 	int		error;
1627 
1628 	if (((mnum = getminor(dev)) == MD_ADM_MINOR) ||
1629 	    (MD_MIN2SET(mnum) >= md_nsets) ||
1630 	    (MD_MIN2UNIT(mnum) >= md_nunits) ||
1631 	    ((ui = MDI_UNIT(mnum)) == NULL))
1632 		return (ENXIO);
1633 
1634 	if (md_ops[ui->ui_opsindex]->md_read  != NULL)
1635 		return ((*md_ops[ui->ui_opsindex]->md_read)
1636 		    (dev, uio, credp));
1637 
1638 	if ((error = md_chk_uio(uio)) != 0)
1639 		return (error);
1640 
1641 	return (physio(mdstrategy, NULL, dev, B_READ, md_minphys, uio));
1642 }
1643 
1644 /*
1645  * This routine performs async raw read operations.  It is called from the
1646  * device switch at normal priority.
1647  *
1648  * The main catch is that the *aio struct which is passed to us may
1649  * specify a read which spans two buffers, which would be contiguous
1650  * on a single partition,  but not on a striped partition. This will
1651  * be handled by mdstrategy.
1652  */
1653 /*ARGSUSED*/
1654 static int
1655 mdaread(dev_t dev, struct aio_req *aio, cred_t *credp)
1656 {
1657 	minor_t		mnum;
1658 	mdi_unit_t	*ui;
1659 	int		error;
1660 
1661 
1662 	if (((mnum = getminor(dev)) == MD_ADM_MINOR) ||
1663 	    (MD_MIN2SET(mnum) >= md_nsets) ||
1664 	    (MD_MIN2UNIT(mnum) >= md_nunits) ||
1665 	    ((ui = MDI_UNIT(mnum)) == NULL))
1666 		return (ENXIO);
1667 
1668 	if (md_ops[ui->ui_opsindex]->md_aread  != NULL)
1669 		return ((*md_ops[ui->ui_opsindex]->md_aread)
1670 		    (dev, aio, credp));
1671 
1672 	if ((error = md_chk_uio(aio->aio_uio)) != 0)
1673 		return (error);
1674 
1675 	return (aphysio(mdstrategy, anocancel, dev, B_READ, md_minphys, aio));
1676 }
1677 
1678 /*
1679  * This routine performs raw write operations.	It is called from the
1680  * device switch at normal priority.
1681  *
1682  * The main catch is that the *uio struct which is passed to us may
1683  * specify a write which spans two buffers, which would be contiguous
1684  * on a single partition,  but not on a striped partition. This is
1685  * handled by mdstrategy.
1686  *
1687  */
1688 /*ARGSUSED*/
1689 static int
1690 mdwrite(dev_t dev, struct uio *uio, cred_t *credp)
1691 {
1692 	minor_t		mnum;
1693 	mdi_unit_t	*ui;
1694 	int		error;
1695 
1696 	if (((mnum = getminor(dev)) == MD_ADM_MINOR) ||
1697 	    (MD_MIN2SET(mnum) >= md_nsets) ||
1698 	    (MD_MIN2UNIT(mnum) >= md_nunits) ||
1699 	    ((ui = MDI_UNIT(mnum)) == NULL))
1700 		return (ENXIO);
1701 
1702 	if (md_ops[ui->ui_opsindex]->md_write  != NULL)
1703 		return ((*md_ops[ui->ui_opsindex]->md_write)
1704 		    (dev, uio, credp));
1705 
1706 	if ((error = md_chk_uio(uio)) != 0)
1707 		return (error);
1708 
1709 	return (physio(mdstrategy, NULL, dev, B_WRITE, md_minphys, uio));
1710 }
1711 
1712 /*
1713  * This routine performs async raw write operations.  It is called from the
1714  * device switch at normal priority.
1715  *
1716  * The main catch is that the *aio struct which is passed to us may
1717  * specify a write which spans two buffers, which would be contiguous
1718  * on a single partition,  but not on a striped partition. This is
1719  * handled by mdstrategy.
1720  *
1721  */
1722 /*ARGSUSED*/
1723 static int
1724 mdawrite(dev_t dev, struct aio_req *aio, cred_t *credp)
1725 {
1726 	minor_t		mnum;
1727 	mdi_unit_t	*ui;
1728 	int		error;
1729 
1730 
1731 	if (((mnum = getminor(dev)) == MD_ADM_MINOR) ||
1732 	    (MD_MIN2SET(mnum) >= md_nsets) ||
1733 	    (MD_MIN2UNIT(mnum) >= md_nunits) ||
1734 	    ((ui = MDI_UNIT(mnum)) == NULL))
1735 		return (ENXIO);
1736 
1737 	if (md_ops[ui->ui_opsindex]->md_awrite  != NULL)
1738 		return ((*md_ops[ui->ui_opsindex]->md_awrite)
1739 		    (dev, aio, credp));
1740 
1741 	if ((error = md_chk_uio(aio->aio_uio)) != 0)
1742 		return (error);
1743 
1744 	return (aphysio(mdstrategy, anocancel, dev, B_WRITE, md_minphys, aio));
1745 }
1746 
1747 int
1748 mdstrategy(struct buf *bp)
1749 {
1750 	minor_t		mnum;
1751 	mdi_unit_t	*ui;
1752 
1753 	ASSERT((bp->b_flags & B_DONE) == 0);
1754 
1755 	if (panicstr)
1756 		md_clr_status(MD_GBL_DAEMONS_LIVE);
1757 
1758 	if (((mnum = getminor(bp->b_edev)) == MD_ADM_MINOR) ||
1759 	    (MD_MIN2SET(mnum) >= md_nsets) ||
1760 	    (MD_MIN2UNIT(mnum) >= md_nunits) ||
1761 	    ((ui = MDI_UNIT(mnum)) == NULL)) {
1762 		bp->b_flags |= B_ERROR;
1763 		bp->b_error = ENXIO;
1764 		bp->b_resid = bp->b_bcount;
1765 		biodone(bp);
1766 		return (0);
1767 	}
1768 
1769 	bp->b_flags &= ~(B_ERROR | B_DONE);
1770 	if (md_ops[ui->ui_opsindex]->md_strategy  != NULL) {
1771 		(*md_ops[ui->ui_opsindex]->md_strategy) (bp, 0, NULL);
1772 	} else {
1773 		(void) errdone(ui, bp, ENXIO);
1774 	}
1775 	return (0);
1776 }
1777 
1778 /*
1779  * Return true if the ioctl is allowed to be multithreaded.
1780  * All the ioctls with MN are sent only from the message handlers through
1781  * rpc.mdcommd, which (via it's own locking mechanism) takes care that not two
1782  * ioctl for the same metadevice are issued at the same time.
1783  * So we are safe here.
1784  * The other ioctls do not mess with any metadevice structures and therefor
1785  * are harmless too, if called multiple times at the same time.
1786  */
1787 static boolean_t
1788 is_mt_ioctl(int cmd) {
1789 
1790 	switch (cmd) {
1791 	case MD_IOCGUNIQMSGID:
1792 	case MD_IOCGVERSION:
1793 	case MD_IOCISOPEN:
1794 	case MD_MN_SET_MM_OWNER:
1795 	case MD_MN_SET_STATE:
1796 	case MD_MN_SUSPEND_WRITES:
1797 	case MD_MN_ALLOCATE_HOTSPARE:
1798 	case MD_MN_SET_SETFLAGS:
1799 	case MD_MN_GET_SETFLAGS:
1800 	case MD_MN_MDDB_OPTRECFIX:
1801 	case MD_MN_MDDB_PARSE:
1802 	case MD_MN_MDDB_BLOCK:
1803 	case MD_MN_DB_USERREQ:
1804 	case MD_IOC_SPSTATUS:
1805 	case MD_MN_COMMD_ERR:
1806 	case MD_MN_SET_COMMD_RUNNING:
1807 	case MD_MN_RESYNC:
1808 	case MD_MN_SETSYNC:
1809 	case MD_MN_POKE_HOTSPARES:
1810 		return (1);
1811 	default:
1812 		return (0);
1813 	}
1814 }
1815 
1816 /*
1817  * This routine implements the ioctl calls for the Virtual Disk System.
1818  * It is called from the device switch at normal priority.
1819  */
1820 /* ARGSUSED */
1821 static int
1822 mdioctl(dev_t dev, int cmd, intptr_t data, int mode, cred_t *cred_p,
1823 	int *rval_p)
1824 {
1825 	minor_t		mnum = getminor(dev);
1826 	mdi_unit_t	*ui;
1827 	IOLOCK		lock;
1828 	int		err;
1829 
1830 	/*
1831 	 * For multinode disksets  number of ioctls are allowed to be
1832 	 * multithreaded.
1833 	 * A fundamental assumption made in this implementation is that
1834 	 * ioctls either do not interact with other md structures  or the
1835 	 * ioctl to the admin device can only occur if the metadevice
1836 	 * device is open. i.e. avoid a race between metaclear and the
1837 	 * progress of a multithreaded ioctl.
1838 	 */
1839 
1840 	if (!is_mt_ioctl(cmd) && md_ioctl_lock_enter() == EINTR) {
1841 		return (EINTR);
1842 	}
1843 
1844 	/*
1845 	 * initialize lock tracker
1846 	 */
1847 	IOLOCK_INIT(&lock);
1848 
1849 	/* Flag to indicate that MD_GBL_IOCTL_LOCK is not acquired */
1850 
1851 	if (is_mt_ioctl(cmd)) {
1852 		/* increment the md_mtioctl_cnt */
1853 		mutex_enter(&md_mx);
1854 		md_mtioctl_cnt++;
1855 		mutex_exit(&md_mx);
1856 		lock.l_flags |= MD_MT_IOCTL;
1857 	}
1858 
1859 	/*
1860 	 * this has been added to prevent notification from re-snarfing
1861 	 * so metaunload will work.  It may interfere with other modules
1862 	 * halt process.
1863 	 */
1864 	if (md_get_status() & (MD_GBL_HALTED | MD_GBL_DAEMONS_DIE))
1865 		return (IOLOCK_RETURN(ENXIO, &lock));
1866 
1867 	/*
1868 	 * admin device ioctls
1869 	 */
1870 	if (mnum == MD_ADM_MINOR) {
1871 		err = md_admin_ioctl(md_expldev(dev), cmd, (void *) data,
1872 					mode, &lock);
1873 	}
1874 
1875 	/*
1876 	 * metadevice ioctls
1877 	 */
1878 	else if ((MD_MIN2SET(mnum) >= md_nsets) ||
1879 	    (MD_MIN2UNIT(mnum) >= md_nunits) ||
1880 	    ((ui = MDI_UNIT(mnum)) == NULL)) {
1881 		err = ENXIO;
1882 	} else if (md_ops[ui->ui_opsindex]->md_ioctl == NULL) {
1883 		err = ENOTTY;
1884 	} else {
1885 		err = (*md_ops[ui->ui_opsindex]->md_ioctl)
1886 		    (dev, cmd, (void *) data, mode, &lock);
1887 	}
1888 
1889 	/*
1890 	 * drop any locks we grabbed
1891 	 */
1892 	return (IOLOCK_RETURN_IOCTLEND(err, &lock));
1893 }
1894 
1895 static int
1896 mddump(dev_t dev, caddr_t addr, daddr_t blkno, int nblk)
1897 {
1898 	minor_t		mnum;
1899 	set_t		setno;
1900 	mdi_unit_t	*ui;
1901 
1902 	if ((mnum = getminor(dev)) == MD_ADM_MINOR)
1903 		return (ENXIO);
1904 
1905 	setno = MD_MIN2SET(mnum);
1906 
1907 	if ((setno >= md_nsets) || (MD_MIN2UNIT(mnum) >= md_nunits) ||
1908 	    ((ui = MDI_UNIT(mnum)) == NULL))
1909 		return (ENXIO);
1910 
1911 
1912 	if ((md_get_setstatus(setno) & MD_SET_SNARFED) == 0)
1913 		return (ENXIO);
1914 
1915 	if (md_ops[ui->ui_opsindex]->md_dump  != NULL)
1916 		return ((*md_ops[ui->ui_opsindex]->md_dump)
1917 		    (dev, addr, blkno, nblk));
1918 
1919 	return (ENXIO);
1920 }
1921 
1922 /*
1923  * Metadevice unit number dispatcher
1924  * When this routine is called it will scan the
1925  * incore unit array and return the avail slot
1926  * hence the unit number to the caller
1927  *
1928  * Return -1 if there is nothing available
1929  */
1930 unit_t
1931 md_get_nextunit(set_t setno)
1932 {
1933 	unit_t	un, start;
1934 
1935 	/*
1936 	 * If nothing available
1937 	 */
1938 	if (md_set[setno].s_un_avail == 0) {
1939 		return (MD_UNITBAD);
1940 	}
1941 
1942 	mutex_enter(&md_mx);
1943 	start = un = md_set[setno].s_un_next;
1944 
1945 	/* LINTED: E_CONSTANT_CONDITION */
1946 	while (1) {
1947 		if (md_set[setno].s_un[un] == NULL) {
1948 			/*
1949 			 * Advance the starting index for the next
1950 			 * md_get_nextunit call
1951 			 */
1952 			if (un == MD_MAXUNITS - 1) {
1953 				md_set[setno].s_un_next = 0;
1954 			} else {
1955 				md_set[setno].s_un_next = un + 1;
1956 			}
1957 			break;
1958 		}
1959 
1960 		un = ((un == MD_MAXUNITS - 1) ? 0 : un + 1);
1961 
1962 		if (un == start) {
1963 			un = MD_UNITBAD;
1964 			break;
1965 		}
1966 
1967 	}
1968 
1969 	mutex_exit(&md_mx);
1970 	return (un);
1971 }
1972