xref: /titanic_52/usr/src/cmd/format/analyze.c (revision 6185db853e024a486ff8837e6784dd290d866112)
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, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 #pragma ident	"%Z%%M%	%I%	%E% SMI"
28 
29 /*
30  * This file contains routines to analyze the surface of a disk.
31  */
32 #include "global.h"
33 #include "analyze.h"
34 #include <stdlib.h>
35 #include <errno.h>
36 #include "misc.h"
37 #include "defect.h"
38 #include "label.h"
39 #include "param.h"
40 #include "checkdev.h"
41 
42 
43 /*
44  * These global variables control the surface analysis process.  They
45  * are set from a command in the defect menu.
46  */
47 int	scan_entire = 1;		/* scan whole disk flag */
48 diskaddr_t	scan_lower = 0;			/* lower bound */
49 diskaddr_t	scan_upper = 0;			/* upper bound */
50 int	scan_correct = 1;		/* correct errors flag */
51 int	scan_stop = 0;			/* stop after error flag */
52 int	scan_loop = 0;			/* loop forever flag */
53 int	scan_passes = 2;		/* number of passes */
54 int	scan_random = 0;		/* random patterns flag */
55 int	scan_size = 0;			/* sectors/scan operation */
56 int	scan_auto = 1;			/* scan after format flag */
57 int	scan_restore_defects = 1;	/* restore defect list after writing */
58 int	scan_restore_label = 1;		/* restore label after writing */
59 
60 /*
61  * These are summary variables to print out info after analysis.
62  * Values less than 0 imply they are invalid.
63  */
64 offset_t	scan_cur_block = -1;		/* current block */
65 int64_t		scan_blocks_fixed = -1;		/* # blocks repaired */
66 
67 /*
68  * This variable is used to tell whether the most recent surface
69  * analysis error was caused by a media defect or some other problem.
70  */
71 int	media_error;			/* error was caused by defect */
72 
73 int	disk_error;			/* disk errors during analysis */
74 
75 /*
76  * These are the data patterns used if random patterns are not chosen.
77  * They are designed to show pattern dependent errors.
78  */
79 static unsigned int	scan_patterns[] = {
80 	0xc6dec6de,
81 	0x6db6db6d,
82 	0x00000000,
83 	0xffffffff,
84 	0xaaaaaaaa,
85 };
86 #define	NPATTERNS	5		/* number of predefined patterns */
87 
88 /*
89  * These are the data patterns from the SunFed requirements document.
90  */
91 static unsigned int purge_patterns[] = {	/* patterns to be written */
92 	0xaaaaaaaa,		/* 10101010... */
93 	0x55555555,		/* 01010101...  == UUUU... */
94 	0xaaaaaaaa,		/* 10101010... */
95 	0xaaaaaaaa,		/* 10101010... */
96 };
97 
98 static unsigned int alpha_pattern =  0x40404040;   /* 10000000...  == @@@@... */
99 
100 /* Function prototypes */
101 #ifdef	__STDC__
102 
103 static int	scan_repair(diskaddr_t bn, int mode);
104 static int	analyze_blocks(int flags, diskaddr_t blkno, int blkcnt,
105 		unsigned data, int init, int driver_flags, int *xfercntp);
106 static int	handle_error_conditions(void);
107 static int	verify_blocks(int flags, diskaddr_t blkno, int blkcnt,
108 		unsigned data, int driver_flags, int *xfercntp);
109 #else	/* __STDC__ */
110 
111 static int	scan_repair();
112 static int	analyze_blocks();
113 static int	handle_error_conditions();
114 static int	verify_blocks();
115 
116 #endif	/* __STDC__ */
117 
118 /*
119  * This routine performs a surface analysis based upon the global
120  * parameters.  It is called from several commands in the defect menu,
121  * and from the format command in the command menu (if post-format
122  * analysis is enable).
123  */
124 int
125 do_scan(flags, mode)
126 	int	flags, mode;
127 {
128 	diskaddr_t	start, end, curnt;
129 	int	pass, size, needinit, data;
130 	int	status, founderr, i, j;
131 	int	error = 0;
132 	int	pattern = 0;
133 	int	xfercnt;
134 
135 	/*
136 	 * Check to be sure we aren't correcting without a defect list
137 	 * if the controller can correct the defect.
138 	 */
139 	if (scan_correct && !EMBEDDED_SCSI && (cur_ops->op_repair != NULL) &&
140 			(cur_list.list == NULL)) {
141 		err_print("Current Defect List must be initialized ");
142 		err_print("to do automatic repair.\n");
143 		return (-1);
144 	}
145 	/*
146 	 * Define the bounds of the scan.
147 	 */
148 	if (scan_entire) {
149 		start = 0;
150 	    if (cur_label == L_TYPE_SOLARIS) {
151 		if (cur_ctype->ctype_flags & CF_SCSI)
152 			end = datasects() - 1;
153 		else
154 			end = physsects() - 1;
155 	    } else if (cur_label == L_TYPE_EFI) {
156 		end = cur_parts->etoc->efi_last_lba;
157 	    }
158 	} else {
159 		start = scan_lower;
160 		end = scan_upper;
161 	}
162 	/*
163 	 * Make sure the user knows if we are scanning over a mounted
164 	 * partition.
165 	 */
166 	if ((flags & (SCAN_PATTERN | SCAN_WRITE)) &&
167 	    (checkmount(start, end))) {
168 		err_print("Cannot do analysis on a mounted partition.\n");
169 		return (-1);
170 	}
171 
172 	/*
173 	 * Make sure the user knows if we are scanning over a
174 	 * partition being used for swapping.
175 	 */
176 	if ((flags & (SCAN_PATTERN | SCAN_WRITE)) &&
177 	    (checkswap(start, end))) {
178 		err_print("Cannot do analysis on a partition \
179 which is currently being used for swapping.\n");
180 		return (-1);
181 	}
182 
183 	/*
184 	 * If we are scanning destructively over certain sectors,
185 	 * we mark the defect list and/or label dirty so it will get rewritten.
186 	 */
187 	if (flags & (SCAN_PATTERN | SCAN_WRITE)) {
188 	    if (cur_label == L_TYPE_SOLARIS) {
189 		if (start < (daddr_t)totalsects() &&
190 				end >= (daddr_t)datasects()) {
191 			if (!EMBEDDED_SCSI) {
192 				cur_list.flags |= LIST_DIRTY;
193 			}
194 			if (cur_disk->disk_flags & DSK_LABEL)
195 				cur_flags |= LABEL_DIRTY;
196 		}
197 	    }
198 	    if (start == 0) {
199 		if (cur_disk->disk_flags & DSK_LABEL)
200 			cur_flags |= LABEL_DIRTY;
201 	    }
202 	}
203 	/*
204 	 * Initialize the summary info on sectors repaired.
205 	 */
206 	scan_blocks_fixed = 0;
207 	/*
208 	 * Loop through the passes of the scan. If required, loop forever.
209 	 */
210 	for (pass = 0; pass < scan_passes || scan_loop; pass++) {
211 		/*
212 		 * Determine the data pattern to use if pattern testing
213 		 * is to be done.
214 		 */
215 		if (flags & SCAN_PATTERN) {
216 			if (scan_random)
217 				data = (int)mrand48();
218 			else
219 				data = scan_patterns[pass % NPPATTERNS];
220 
221 			if (flags & SCAN_PURGE) {
222 				flags &= ~(SCAN_PURGE_READ_PASS
223 						| SCAN_PURGE_ALPHA_PASS);
224 				switch (pattern % (NPPATTERNS + 1)) {
225 				case NPPATTERNS:
226 					pattern = 0;
227 					if (!error) {
228 					    fmt_print(
229 "\nThe last %d passes were successful, running alpha pattern pass", NPPATTERNS);
230 					    flags |= SCAN_PURGE_ALPHA_PASS;
231 					    data = alpha_pattern;
232 					} else {
233 					    data = purge_patterns[pattern];
234 					    pattern++;
235 					};
236 					break;
237 				case READPATTERN:
238 					flags |=  SCAN_PURGE_READ_PASS;
239 				default:
240 					data = purge_patterns[pattern];
241 					pattern++;
242 					break;
243 				}
244 			}
245 			fmt_print("\n        pass %d", pass);
246 			fmt_print(" - pattern = 0x%x", data);
247 		} else
248 			fmt_print("\n        pass %d", pass);
249 
250 		fmt_print("\n");
251 		/*
252 		 * Mark the pattern buffer as corrupt, since it
253 		 * hasn't been initialized.
254 		 */
255 		needinit = 1;
256 		/*
257 		 * Print the first block number to the log file if
258 		 * logging is on so there is some record of what
259 		 * analysis was performed.
260 		 */
261 		if (log_file) {
262 			pr_dblock(log_print, start);
263 			log_print("\n");
264 		}
265 		/*
266 		 * Loop through this pass, each time analyzing an amount
267 		 * specified by the global parameters.
268 		 */
269 		xfercnt = 0;
270 		for (curnt = start; curnt <= end; curnt += size) {
271 			if ((end - curnt) < scan_size)
272 				size = end - curnt + 1;
273 			else
274 				size = scan_size;
275 			/*
276 			 * Print out where we are, so we don't look dead.
277 			 * Also store it in summary info for logging.
278 			 */
279 			scan_cur_block = curnt;
280 			nolog_print("   ");
281 			pr_dblock(nolog_print, curnt);
282 			nolog_print("  \015");
283 			(void) fflush(stdout);
284 			disk_error = 0;
285 			/*
286 			 * Do the actual analysis.
287 			 */
288 			status = analyze_blocks(flags, (daddr_t)curnt, size,
289 			    (unsigned)data, needinit, (F_ALLERRS | F_SILENT),
290 			    &xfercnt);
291 			/*
292 			 * If there were no errors, the pattern buffer is
293 			 * still initialized, and we just loop to next chunk.
294 			 */
295 			needinit = 0;
296 			if (!status)
297 				continue;
298 			/*
299 			 * There was an error. Check if surface analysis
300 			 * can be continued.
301 			 */
302 			if (handle_error_conditions()) {
303 				scan_blocks_fixed = scan_cur_block = -1;
304 				return (-1);
305 			}
306 			/*
307 			 * There was an error. Mark the pattern buffer
308 			 * corrupt so it will get reinitialized.
309 			 */
310 			needinit = 1;
311 			/*
312 			 * If it was not a media error, ignore it.
313 			 */
314 			if (!media_error)
315 				continue;
316 			/*
317 			 * Loop 5 times through each sector of the chunk,
318 			 * analyzing them individually.
319 			 */
320 			nolog_print("   ");
321 			pr_dblock(nolog_print, curnt);
322 			nolog_print("  \015");
323 			(void) fflush(stdout);
324 			founderr = 0;
325 			for (j = 0; j < size * 5; j++) {
326 				i = j % size;
327 				disk_error = 0;
328 				status = analyze_blocks(flags, (daddr_t)
329 				    (curnt + i), 1, (unsigned)data, needinit,
330 				    F_ALLERRS, NULL);
331 				needinit = 0;
332 				if (!status)
333 					continue;
334 				/*
335 				 * There was an error. Check if surface analysis
336 				 * can be continued.
337 				 */
338 				if (handle_error_conditions()) {
339 					scan_blocks_fixed = scan_cur_block = -1;
340 					return (-1);
341 				}
342 				/*
343 				 * An error occurred.  Mark the buffer
344 				 * corrupt and see if it was media
345 				 * related.
346 				 */
347 				needinit = 1;
348 				if (!media_error)
349 					continue;
350 				/*
351 				 * We found a bad sector. Print out a message
352 				 * and fix it if required.
353 				 */
354 				founderr = 1;
355 				if (scan_correct && (flags != SCAN_VALID)) {
356 					if (scan_repair(curnt+i, mode)) {
357 						error = -1;
358 					}
359 				} else
360 					err_print("\n");
361 				/*
362 				 * Stop after the error if required.
363 				 */
364 				if (scan_stop)
365 					goto out;
366 			}
367 			/*
368 			 * Mark the pattern buffer corrupt to be safe.
369 			 */
370 			needinit = 1;
371 			/*
372 			 * We didn't find an individual sector that was bad.
373 			 * Print out a warning.
374 			 */
375 			if (!founderr) {
376 				err_print("Warning: unable to pinpoint ");
377 				err_print("defective block.\n");
378 			}
379 		}
380 		/*
381 		 * Print the end of each pass to the log file.
382 		 */
383 		enter_critical();
384 		if (log_file) {
385 			pr_dblock(log_print, scan_cur_block);
386 			log_print("\n");
387 		}
388 		scan_cur_block = -1;
389 		exit_critical();
390 		fmt_print("\n");
391 
392 		/*
393 		 * alternate the read and write for SCAN_VERIFY test
394 		 */
395 		if (flags & SCAN_VERIFY) {
396 			flags ^= SCAN_VERIFY_READ_PASS;
397 		}
398 	}
399 out:
400 	/*
401 	 * We got here either by giving up after an error or falling
402 	 * through after all passes were completed.
403 	 */
404 	fmt_print("\n");
405 	enter_critical();
406 	/*
407 	 * If the defect list is dirty, write it to disk,
408 	 * if scan_restore_defects (the default) is true.
409 	 */
410 	if (!EMBEDDED_SCSI && (cur_list.flags & LIST_DIRTY) &&
411 				(scan_restore_defects)) {
412 		cur_list.flags = 0;
413 		write_deflist(&cur_list);
414 		}
415 	/*
416 	 * If the label is dirty, write it to disk.
417 	 * if scan_restore_label (the default) is true.
418 	 */
419 	if ((cur_flags & LABEL_DIRTY) && (scan_restore_label)) {
420 		cur_flags &= ~LABEL_DIRTY;
421 		(void) write_label();
422 	}
423 	/*
424 	 * If we dropped down to here after an error, we need to write
425 	 * the final block number to the log file for record keeping.
426 	 */
427 	if (log_file && scan_cur_block >= 0) {
428 		pr_dblock(log_print, scan_cur_block);
429 		log_print("\n");
430 	}
431 	fmt_print("Total of %lld defective blocks repaired.\n",
432 		scan_blocks_fixed);
433 	/*
434 	 * Reinitialize the logging variables so they don't get used
435 	 * when they are not really valid.
436 	 */
437 	scan_blocks_fixed = scan_cur_block = -1;
438 	exit_critical();
439 	return (error);
440 }
441 
442 
443 /*
444  * This routine is called to repair a bad block discovered
445  * during a scan operation.  Return 0 for success, 1 for failure.
446  * (This has been extracted out of do_scan(), to simplify it.)
447  */
448 static int
449 scan_repair(bn, mode)
450 	diskaddr_t	bn;
451 	int	mode;
452 {
453 	int	status;
454 	int	result = 1;
455 	char	buf[SECSIZE];
456 	int	buf_is_good;
457 	int	i;
458 
459 	if (cur_ops->op_repair == NULL) {
460 		err_print("Warning: Controller does ");
461 		err_print("not support repairing.\n\n");
462 		return (result);
463 	}
464 
465 	enter_critical();
466 
467 	/*
468 	 * Determine if the error appears to be hard or soft.  We
469 	 * already assume there's an error.  If we can get any
470 	 * good data out of the sector, write that data back
471 	 * after the repair.
472 	 */
473 	buf_is_good = 0;
474 	for (i = 0; i < 5; i++) {
475 		status = (*cur_ops->op_rdwr)(DIR_READ, cur_file, bn, 1,
476 				buf, F_SILENT, NULL);
477 		if (status == 0) {
478 			buf_is_good = 1;
479 			break;
480 		}
481 	}
482 
483 	fmt_print("Repairing %s error on %llu (",
484 				buf_is_good ? "soft" : "hard", bn);
485 	pr_dblock(fmt_print, bn);
486 	fmt_print(")...");
487 
488 	status = (*cur_ops->op_repair)(bn, mode);
489 	if (status) {
490 		/*
491 		 * If the repair failed, we note it and will return the
492 		 * failure. However, the analysis goes on.
493 		 */
494 		fmt_print("failed.\n\n");
495 	} else {
496 		/*
497 		 * The repair worked.  Write the good data we could
498 		 * recover from the failed block, if possible.
499 		 * If not, zero the block.  In doing so, try to
500 		 * determine if the new block appears ok.
501 		 */
502 		if (!buf_is_good) {
503 			bzero(buf, SECSIZE);
504 			fmt_print("Warning: Block %llu zero-filled.\n", bn);
505 		} else {
506 			fmt_print("ok.\n");
507 		}
508 		status = (*cur_ops->op_rdwr)(DIR_WRITE, cur_file, bn,
509 					1, buf, (F_SILENT | F_ALLERRS), NULL);
510 		if (status == 0) {
511 			status = (*cur_ops->op_rdwr)(DIR_READ, cur_file, bn,
512 					1, buf, (F_SILENT | F_ALLERRS), NULL);
513 		}
514 		if (status) {
515 			fmt_print("The new block also appears defective.\n");
516 		}
517 		fmt_print("\n");
518 		/*
519 		 * add the defect to the list and write the list out.
520 		 * Also, kill the working list so it will get resynced
521 		 * with the current list.
522 		 *
523 		 * For embedded scsi, we don't require a defect list.
524 		 * However, if we have one, add the defect if the
525 		 * list includes the grown list.  If not, kill it
526 		 * to force a resync if we need the list later.
527 		 */
528 		if (EMBEDDED_SCSI) {
529 			if (cur_list.list != NULL) {
530 				if (cur_list.flags & LIST_PGLIST) {
531 					add_ldef(bn, &cur_list);
532 				} else {
533 					kill_deflist(&cur_list);
534 				}
535 			}
536 		/*
537 		 * The next "if" statement reflects the fix for
538 		 * bug id 1026096 where format keeps adding the
539 		 * same defect to the defect list.
540 		 */
541 		} else if (cur_ctype->ctype_flags & CF_WLIST) {
542 			kill_deflist(&cur_list);
543 			(*cur_ops->op_ex_cur)(&cur_list);
544 			fmt_print("Current list updated\n");
545 		} else {
546 			add_ldef(bn, &cur_list);
547 			write_deflist(&cur_list);
548 		}
549 		kill_deflist(&work_list);
550 
551 		/* Log the repair.  */
552 		scan_blocks_fixed++;
553 
554 		/* return ok */
555 		result = 0;
556 	}
557 
558 	exit_critical();
559 
560 	return (result);
561 }
562 
563 
564 /*
565  * This routine analyzes a set of sectors on the disk.  It simply returns
566  * an error if a defect is found.  It is called by do_scan().
567  */
568 static int
569 analyze_blocks(flags, blkno, blkcnt, data, init, driver_flags, xfercntp)
570 	int	flags, driver_flags, blkcnt, init;
571 	register unsigned data;
572 	diskaddr_t	blkno;
573 	int	*xfercntp;
574 {
575 	int	corrupt = 0;
576 	register int	status, i, nints;
577 	register unsigned *ptr = (uint_t *)pattern_buf;
578 
579 	media_error = 0;
580 	if (flags & SCAN_VERIFY) {
581 		return (verify_blocks(flags, blkno, blkcnt, data,
582 		    driver_flags, xfercntp));
583 	}
584 
585 	/*
586 	 * Initialize the pattern buffer if necessary.
587 	 */
588 	nints = blkcnt * SECSIZE / sizeof (int);
589 	if ((flags & SCAN_PATTERN) && init) {
590 		for (i = 0; i < nints; i++)
591 			*((int *)((int *)pattern_buf + i)) = data;
592 	}
593 	/*
594 	 * Lock out interrupts so we can insure valid data will get
595 	 * restored. This is necessary because there are modes
596 	 * of scanning that corrupt the disk data then restore it at
597 	 * the end of the analysis.
598 	 */
599 	enter_critical();
600 	/*
601 	 * If the disk data is valid, read it into the data buffer.
602 	 */
603 	if (flags & SCAN_VALID) {
604 		status = (*cur_ops->op_rdwr)(DIR_READ, cur_file, blkno,
605 		    blkcnt, (caddr_t)cur_buf, driver_flags, xfercntp);
606 		if (status)
607 			goto bad;
608 	}
609 	/*
610 	 * If we are doing pattern testing, write and read the pattern
611 	 * from the pattern buffer.
612 	 */
613 	if (flags & SCAN_PATTERN) {
614 		/*
615 		 * If the disk data was valid, mark it corrupt so we know
616 		 * to restore it later.
617 		 */
618 		if (flags & SCAN_VALID)
619 			corrupt++;
620 		/*
621 		 * Only write if we're not on the read pass of SCAN_PURGE.
622 		 */
623 		if (!(flags & SCAN_PURGE_READ_PASS)) {
624 			status = (*cur_ops->op_rdwr)(DIR_WRITE, cur_file, blkno,
625 			    blkcnt, (caddr_t)pattern_buf, driver_flags,
626 			    xfercntp);
627 			if (status)
628 			    goto bad;
629 		}
630 		/*
631 		 * Only read if we are on the read pass of SCAN_PURGE, if we
632 		 * are purging.
633 		 */
634 		if ((!(flags & SCAN_PURGE)) || (flags & SCAN_PURGE_READ_PASS)) {
635 			status = (*cur_ops->op_rdwr)(DIR_READ, cur_file, blkno,
636 			    blkcnt, (caddr_t)pattern_buf, driver_flags,
637 			    xfercntp);
638 			if (status)
639 			    goto bad;
640 		}
641 	}
642 	/*
643 	 * If we are doing a data compare, make sure the pattern
644 	 * came back intact.
645 	 * Only compare if we are on the read pass of SCAN_PURGE, or
646 	 * we wrote random data instead of the expected data pattern.
647 	 */
648 	if ((flags & SCAN_COMPARE) || (flags & SCAN_PURGE_READ_PASS)) {
649 		for (i = nints, ptr = (uint_t *)pattern_buf; i; i--)
650 			if (*ptr++ != data) {
651 				err_print("Data miscompare error (expecting ");
652 				err_print("0x%x, got 0x%x) at ", data,
653 					*((int *)((int *)pattern_buf +
654 					(nints - i))));
655 				pr_dblock(err_print, blkno);
656 				err_print(", offset = 0x%x.\n",
657 					(nints - i) * sizeof (int));
658 				goto bad;
659 			}
660 	}
661 	/*
662 	 * If we are supposed to write data out, do so.
663 	 */
664 	if (flags & SCAN_WRITE) {
665 		status = (*cur_ops->op_rdwr)(DIR_WRITE, cur_file, blkno,
666 		    blkcnt, (caddr_t)cur_buf, driver_flags, xfercntp);
667 		if (status)
668 			goto bad;
669 	}
670 	exit_critical();
671 	/*
672 	 * No errors occurred, return ok.
673 	 */
674 	return (0);
675 bad:
676 	/*
677 	 * There was an error.  If the data was corrupted, we write it
678 	 * out from the data buffer to restore it.
679 	 */
680 	if (corrupt) {
681 		if ((*cur_ops->op_rdwr)(DIR_WRITE, cur_file, blkno,
682 				blkcnt, (caddr_t)cur_buf, F_NORMAL, xfercntp))
683 		err_print("Warning: unable to restore original data.\n");
684 	}
685 	exit_critical();
686 	/*
687 	 * Return the error.
688 	 */
689 	return (-1);
690 }
691 
692 
693 /*
694  * This routine analyzes a set of sectors on the disk. It simply returns
695  * an error if a defect is found.  It is called by analyze_blocks().
696  * For simplicity, this is done as a separate function instead of
697  * making the analyze_block routine complex.
698  *
699  * This routine implements the 'verify' command.  It writes the disk
700  * by writing unique data for each block; after the write pass, it
701  * reads the data and verifies for correctness. Note that the entire
702  * disk (or the range of disk) is fully written first and then read.
703  * This should eliminate any caching effect on the drives.
704  */
705 static int
706 verify_blocks(int flags,
707 		diskaddr_t blkno,
708 		int blkcnt,
709 		unsigned data,
710 		int driver_flags,
711 		int *xfercntp)
712 {
713 	int		status, i, nints;
714 	unsigned	*ptr = (uint_t *)pattern_buf;
715 
716 	nints = SECSIZE / sizeof (int);
717 
718 	/*
719 	 * Initialize the pattern buffer if we are in write pass.
720 	 * Use the block number itself as data, each block has unique
721 	 * buffer data that way.
722 	 */
723 	if (!(flags & SCAN_VERIFY_READ_PASS)) {
724 		for (data = blkno; data < blkno + blkcnt; data++) {
725 			for (i = 0; i < nints; i++) {
726 				*ptr++ = data;
727 			}
728 		}
729 		ptr = (uint_t *)pattern_buf;
730 	}
731 
732 	/*
733 	 * Only write if we're not on the read pass of SCAN_VERIFY.
734 	 */
735 	if (!(flags & SCAN_VERIFY_READ_PASS)) {
736 		status = (*cur_ops->op_rdwr)(DIR_WRITE, cur_file, blkno,
737 		    blkcnt, (caddr_t)pattern_buf, driver_flags, xfercntp);
738 		if (status)
739 			goto bad;
740 	} else {
741 		/*
742 		 * Only read if we are on the read pass of SCAN_VERIFY
743 		 */
744 		status = (*cur_ops->op_rdwr)(DIR_READ, cur_file, blkno,
745 		    blkcnt, (caddr_t)pattern_buf, driver_flags, xfercntp);
746 		if (status)
747 			goto bad;
748 		/*
749 		 * compare and make sure the pattern came back intact.
750 		 */
751 		for (data = blkno; data < blkno + blkcnt; data++) {
752 		    for (i = 0; i < nints; i++) {
753 			if (*ptr++ != data) {
754 			    ptr--;
755 			    err_print("Data miscompare error (expecting "
756 				"0x%x, got 0x%x) at ", data, *ptr);
757 			    pr_dblock(err_print, blkno);
758 			    err_print(", offset = 0x%x.\n", (ptr -
759 				(uint_t *)pattern_buf) * sizeof (int));
760 			    goto bad;
761 			}
762 		    }
763 		}
764 	}
765 	/*
766 	 * No errors occurred, return ok.
767 	 */
768 	return (0);
769 bad:
770 	return (-1);
771 }
772 
773 
774 static int
775 handle_error_conditions()
776 {
777 
778 	/*
779 	 * Check if the errno is ENXIO.
780 	 */
781 	if (errno == ENXIO) {
782 		fmt_print("\n\nWarning:Cannot access drive, ");
783 		fmt_print("aborting surface analysis.\n");
784 		return (-1);
785 	}
786 	/*
787 	 * check for disk errors
788 	 */
789 	switch (disk_error) {
790 	case DISK_STAT_RESERVED:
791 	case DISK_STAT_UNAVAILABLE:
792 		fmt_print("\n\nWarning:Drive may be reserved ");
793 		fmt_print("or has been removed, ");
794 		fmt_print("aborting surface analysis.\n");
795 		return (-1);
796 	case DISK_STAT_NOTREADY:
797 		fmt_print("\n\nWarning: Drive not ready, ");
798 		fmt_print("aborting surface analysis.\n");
799 		return (-1);
800 	case DISK_STAT_DATA_PROTECT:
801 		fmt_print("\n\nWarning: Drive is write protected, ");
802 		fmt_print("aborting surface analysis.\n");
803 		return (-1);
804 	default:
805 		break;
806 	}
807 	return (0);
808 }
809