xref: /linux/drivers/md/md.c (revision dfc349402de8e95f6a42e8341e9ea193b718eee3)
1 /*
2    md.c : Multiple Devices driver for Linux
3 	  Copyright (C) 1998, 1999, 2000 Ingo Molnar
4 
5      completely rewritten, based on the MD driver code from Marc Zyngier
6 
7    Changes:
8 
9    - RAID-1/RAID-5 extensions by Miguel de Icaza, Gadi Oxman, Ingo Molnar
10    - RAID-6 extensions by H. Peter Anvin <hpa@zytor.com>
11    - boot support for linear and striped mode by Harald Hoyer <HarryH@Royal.Net>
12    - kerneld support by Boris Tobotras <boris@xtalk.msk.su>
13    - kmod support by: Cyrus Durgin
14    - RAID0 bugfixes: Mark Anthony Lisher <markal@iname.com>
15    - Devfs support by Richard Gooch <rgooch@atnf.csiro.au>
16 
17    - lots of fixes and improvements to the RAID1/RAID5 and generic
18      RAID code (such as request based resynchronization):
19 
20      Neil Brown <neilb@cse.unsw.edu.au>.
21 
22    - persistent bitmap code
23      Copyright (C) 2003-2004, Paul Clements, SteelEye Technology, Inc.
24 
25    This program is free software; you can redistribute it and/or modify
26    it under the terms of the GNU General Public License as published by
27    the Free Software Foundation; either version 2, or (at your option)
28    any later version.
29 
30    You should have received a copy of the GNU General Public License
31    (for example /usr/src/linux/COPYING); if not, write to the Free
32    Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
33 */
34 
35 #include <linux/kthread.h>
36 #include <linux/blkdev.h>
37 #include <linux/sysctl.h>
38 #include <linux/seq_file.h>
39 #include <linux/buffer_head.h> /* for invalidate_bdev */
40 #include <linux/poll.h>
41 #include <linux/ctype.h>
42 #include <linux/hdreg.h>
43 #include <linux/proc_fs.h>
44 #include <linux/random.h>
45 #include <linux/reboot.h>
46 #include <linux/file.h>
47 #include <linux/delay.h>
48 #include <linux/raid/md_p.h>
49 #include <linux/raid/md_u.h>
50 #include "md.h"
51 #include "bitmap.h"
52 
53 #define DEBUG 0
54 #define dprintk(x...) ((void)(DEBUG && printk(x)))
55 
56 
57 #ifndef MODULE
58 static void autostart_arrays(int part);
59 #endif
60 
61 static LIST_HEAD(pers_list);
62 static DEFINE_SPINLOCK(pers_lock);
63 
64 static void md_print_devices(void);
65 
66 static DECLARE_WAIT_QUEUE_HEAD(resync_wait);
67 
68 #define MD_BUG(x...) { printk("md: bug in file %s, line %d\n", __FILE__, __LINE__); md_print_devices(); }
69 
70 /*
71  * Current RAID-1,4,5 parallel reconstruction 'guaranteed speed limit'
72  * is 1000 KB/sec, so the extra system load does not show up that much.
73  * Increase it if you want to have more _guaranteed_ speed. Note that
74  * the RAID driver will use the maximum available bandwidth if the IO
75  * subsystem is idle. There is also an 'absolute maximum' reconstruction
76  * speed limit - in case reconstruction slows down your system despite
77  * idle IO detection.
78  *
79  * you can change it via /proc/sys/dev/raid/speed_limit_min and _max.
80  * or /sys/block/mdX/md/sync_speed_{min,max}
81  */
82 
83 static int sysctl_speed_limit_min = 1000;
84 static int sysctl_speed_limit_max = 200000;
85 static inline int speed_min(mddev_t *mddev)
86 {
87 	return mddev->sync_speed_min ?
88 		mddev->sync_speed_min : sysctl_speed_limit_min;
89 }
90 
91 static inline int speed_max(mddev_t *mddev)
92 {
93 	return mddev->sync_speed_max ?
94 		mddev->sync_speed_max : sysctl_speed_limit_max;
95 }
96 
97 static struct ctl_table_header *raid_table_header;
98 
99 static ctl_table raid_table[] = {
100 	{
101 		.ctl_name	= DEV_RAID_SPEED_LIMIT_MIN,
102 		.procname	= "speed_limit_min",
103 		.data		= &sysctl_speed_limit_min,
104 		.maxlen		= sizeof(int),
105 		.mode		= S_IRUGO|S_IWUSR,
106 		.proc_handler	= &proc_dointvec,
107 	},
108 	{
109 		.ctl_name	= DEV_RAID_SPEED_LIMIT_MAX,
110 		.procname	= "speed_limit_max",
111 		.data		= &sysctl_speed_limit_max,
112 		.maxlen		= sizeof(int),
113 		.mode		= S_IRUGO|S_IWUSR,
114 		.proc_handler	= &proc_dointvec,
115 	},
116 	{ .ctl_name = 0 }
117 };
118 
119 static ctl_table raid_dir_table[] = {
120 	{
121 		.ctl_name	= DEV_RAID,
122 		.procname	= "raid",
123 		.maxlen		= 0,
124 		.mode		= S_IRUGO|S_IXUGO,
125 		.child		= raid_table,
126 	},
127 	{ .ctl_name = 0 }
128 };
129 
130 static ctl_table raid_root_table[] = {
131 	{
132 		.ctl_name	= CTL_DEV,
133 		.procname	= "dev",
134 		.maxlen		= 0,
135 		.mode		= 0555,
136 		.child		= raid_dir_table,
137 	},
138 	{ .ctl_name = 0 }
139 };
140 
141 static const struct block_device_operations md_fops;
142 
143 static int start_readonly;
144 
145 /*
146  * We have a system wide 'event count' that is incremented
147  * on any 'interesting' event, and readers of /proc/mdstat
148  * can use 'poll' or 'select' to find out when the event
149  * count increases.
150  *
151  * Events are:
152  *  start array, stop array, error, add device, remove device,
153  *  start build, activate spare
154  */
155 static DECLARE_WAIT_QUEUE_HEAD(md_event_waiters);
156 static atomic_t md_event_count;
157 void md_new_event(mddev_t *mddev)
158 {
159 	atomic_inc(&md_event_count);
160 	wake_up(&md_event_waiters);
161 }
162 EXPORT_SYMBOL_GPL(md_new_event);
163 
164 /* Alternate version that can be called from interrupts
165  * when calling sysfs_notify isn't needed.
166  */
167 static void md_new_event_inintr(mddev_t *mddev)
168 {
169 	atomic_inc(&md_event_count);
170 	wake_up(&md_event_waiters);
171 }
172 
173 /*
174  * Enables to iterate over all existing md arrays
175  * all_mddevs_lock protects this list.
176  */
177 static LIST_HEAD(all_mddevs);
178 static DEFINE_SPINLOCK(all_mddevs_lock);
179 
180 
181 /*
182  * iterates through all used mddevs in the system.
183  * We take care to grab the all_mddevs_lock whenever navigating
184  * the list, and to always hold a refcount when unlocked.
185  * Any code which breaks out of this loop while own
186  * a reference to the current mddev and must mddev_put it.
187  */
188 #define for_each_mddev(mddev,tmp)					\
189 									\
190 	for (({ spin_lock(&all_mddevs_lock); 				\
191 		tmp = all_mddevs.next;					\
192 		mddev = NULL;});					\
193 	     ({ if (tmp != &all_mddevs)					\
194 			mddev_get(list_entry(tmp, mddev_t, all_mddevs));\
195 		spin_unlock(&all_mddevs_lock);				\
196 		if (mddev) mddev_put(mddev);				\
197 		mddev = list_entry(tmp, mddev_t, all_mddevs);		\
198 		tmp != &all_mddevs;});					\
199 	     ({ spin_lock(&all_mddevs_lock);				\
200 		tmp = tmp->next;})					\
201 		)
202 
203 
204 /* Rather than calling directly into the personality make_request function,
205  * IO requests come here first so that we can check if the device is
206  * being suspended pending a reconfiguration.
207  * We hold a refcount over the call to ->make_request.  By the time that
208  * call has finished, the bio has been linked into some internal structure
209  * and so is visible to ->quiesce(), so we don't need the refcount any more.
210  */
211 static int md_make_request(struct request_queue *q, struct bio *bio)
212 {
213 	mddev_t *mddev = q->queuedata;
214 	int rv;
215 	if (mddev == NULL || mddev->pers == NULL) {
216 		bio_io_error(bio);
217 		return 0;
218 	}
219 	rcu_read_lock();
220 	if (mddev->suspended) {
221 		DEFINE_WAIT(__wait);
222 		for (;;) {
223 			prepare_to_wait(&mddev->sb_wait, &__wait,
224 					TASK_UNINTERRUPTIBLE);
225 			if (!mddev->suspended)
226 				break;
227 			rcu_read_unlock();
228 			schedule();
229 			rcu_read_lock();
230 		}
231 		finish_wait(&mddev->sb_wait, &__wait);
232 	}
233 	atomic_inc(&mddev->active_io);
234 	rcu_read_unlock();
235 	rv = mddev->pers->make_request(q, bio);
236 	if (atomic_dec_and_test(&mddev->active_io) && mddev->suspended)
237 		wake_up(&mddev->sb_wait);
238 
239 	return rv;
240 }
241 
242 static void mddev_suspend(mddev_t *mddev)
243 {
244 	BUG_ON(mddev->suspended);
245 	mddev->suspended = 1;
246 	synchronize_rcu();
247 	wait_event(mddev->sb_wait, atomic_read(&mddev->active_io) == 0);
248 	mddev->pers->quiesce(mddev, 1);
249 	md_unregister_thread(mddev->thread);
250 	mddev->thread = NULL;
251 	/* we now know that no code is executing in the personality module,
252 	 * except possibly the tail end of a ->bi_end_io function, but that
253 	 * is certain to complete before the module has a chance to get
254 	 * unloaded
255 	 */
256 }
257 
258 static void mddev_resume(mddev_t *mddev)
259 {
260 	mddev->suspended = 0;
261 	wake_up(&mddev->sb_wait);
262 	mddev->pers->quiesce(mddev, 0);
263 }
264 
265 int mddev_congested(mddev_t *mddev, int bits)
266 {
267 	return mddev->suspended;
268 }
269 EXPORT_SYMBOL(mddev_congested);
270 
271 
272 static inline mddev_t *mddev_get(mddev_t *mddev)
273 {
274 	atomic_inc(&mddev->active);
275 	return mddev;
276 }
277 
278 static void mddev_delayed_delete(struct work_struct *ws);
279 
280 static void mddev_put(mddev_t *mddev)
281 {
282 	if (!atomic_dec_and_lock(&mddev->active, &all_mddevs_lock))
283 		return;
284 	if (!mddev->raid_disks && list_empty(&mddev->disks) &&
285 	    !mddev->hold_active) {
286 		list_del(&mddev->all_mddevs);
287 		if (mddev->gendisk) {
288 			/* we did a probe so need to clean up.
289 			 * Call schedule_work inside the spinlock
290 			 * so that flush_scheduled_work() after
291 			 * mddev_find will succeed in waiting for the
292 			 * work to be done.
293 			 */
294 			INIT_WORK(&mddev->del_work, mddev_delayed_delete);
295 			schedule_work(&mddev->del_work);
296 		} else
297 			kfree(mddev);
298 	}
299 	spin_unlock(&all_mddevs_lock);
300 }
301 
302 static mddev_t * mddev_find(dev_t unit)
303 {
304 	mddev_t *mddev, *new = NULL;
305 
306  retry:
307 	spin_lock(&all_mddevs_lock);
308 
309 	if (unit) {
310 		list_for_each_entry(mddev, &all_mddevs, all_mddevs)
311 			if (mddev->unit == unit) {
312 				mddev_get(mddev);
313 				spin_unlock(&all_mddevs_lock);
314 				kfree(new);
315 				return mddev;
316 			}
317 
318 		if (new) {
319 			list_add(&new->all_mddevs, &all_mddevs);
320 			spin_unlock(&all_mddevs_lock);
321 			new->hold_active = UNTIL_IOCTL;
322 			return new;
323 		}
324 	} else if (new) {
325 		/* find an unused unit number */
326 		static int next_minor = 512;
327 		int start = next_minor;
328 		int is_free = 0;
329 		int dev = 0;
330 		while (!is_free) {
331 			dev = MKDEV(MD_MAJOR, next_minor);
332 			next_minor++;
333 			if (next_minor > MINORMASK)
334 				next_minor = 0;
335 			if (next_minor == start) {
336 				/* Oh dear, all in use. */
337 				spin_unlock(&all_mddevs_lock);
338 				kfree(new);
339 				return NULL;
340 			}
341 
342 			is_free = 1;
343 			list_for_each_entry(mddev, &all_mddevs, all_mddevs)
344 				if (mddev->unit == dev) {
345 					is_free = 0;
346 					break;
347 				}
348 		}
349 		new->unit = dev;
350 		new->md_minor = MINOR(dev);
351 		new->hold_active = UNTIL_STOP;
352 		list_add(&new->all_mddevs, &all_mddevs);
353 		spin_unlock(&all_mddevs_lock);
354 		return new;
355 	}
356 	spin_unlock(&all_mddevs_lock);
357 
358 	new = kzalloc(sizeof(*new), GFP_KERNEL);
359 	if (!new)
360 		return NULL;
361 
362 	new->unit = unit;
363 	if (MAJOR(unit) == MD_MAJOR)
364 		new->md_minor = MINOR(unit);
365 	else
366 		new->md_minor = MINOR(unit) >> MdpMinorShift;
367 
368 	mutex_init(&new->open_mutex);
369 	mutex_init(&new->reconfig_mutex);
370 	INIT_LIST_HEAD(&new->disks);
371 	INIT_LIST_HEAD(&new->all_mddevs);
372 	init_timer(&new->safemode_timer);
373 	atomic_set(&new->active, 1);
374 	atomic_set(&new->openers, 0);
375 	atomic_set(&new->active_io, 0);
376 	spin_lock_init(&new->write_lock);
377 	init_waitqueue_head(&new->sb_wait);
378 	init_waitqueue_head(&new->recovery_wait);
379 	new->reshape_position = MaxSector;
380 	new->resync_min = 0;
381 	new->resync_max = MaxSector;
382 	new->level = LEVEL_NONE;
383 
384 	goto retry;
385 }
386 
387 static inline int mddev_lock(mddev_t * mddev)
388 {
389 	return mutex_lock_interruptible(&mddev->reconfig_mutex);
390 }
391 
392 static inline int mddev_is_locked(mddev_t *mddev)
393 {
394 	return mutex_is_locked(&mddev->reconfig_mutex);
395 }
396 
397 static inline int mddev_trylock(mddev_t * mddev)
398 {
399 	return mutex_trylock(&mddev->reconfig_mutex);
400 }
401 
402 static inline void mddev_unlock(mddev_t * mddev)
403 {
404 	mutex_unlock(&mddev->reconfig_mutex);
405 
406 	md_wakeup_thread(mddev->thread);
407 }
408 
409 static mdk_rdev_t * find_rdev_nr(mddev_t *mddev, int nr)
410 {
411 	mdk_rdev_t *rdev;
412 
413 	list_for_each_entry(rdev, &mddev->disks, same_set)
414 		if (rdev->desc_nr == nr)
415 			return rdev;
416 
417 	return NULL;
418 }
419 
420 static mdk_rdev_t * find_rdev(mddev_t * mddev, dev_t dev)
421 {
422 	mdk_rdev_t *rdev;
423 
424 	list_for_each_entry(rdev, &mddev->disks, same_set)
425 		if (rdev->bdev->bd_dev == dev)
426 			return rdev;
427 
428 	return NULL;
429 }
430 
431 static struct mdk_personality *find_pers(int level, char *clevel)
432 {
433 	struct mdk_personality *pers;
434 	list_for_each_entry(pers, &pers_list, list) {
435 		if (level != LEVEL_NONE && pers->level == level)
436 			return pers;
437 		if (strcmp(pers->name, clevel)==0)
438 			return pers;
439 	}
440 	return NULL;
441 }
442 
443 /* return the offset of the super block in 512byte sectors */
444 static inline sector_t calc_dev_sboffset(struct block_device *bdev)
445 {
446 	sector_t num_sectors = bdev->bd_inode->i_size / 512;
447 	return MD_NEW_SIZE_SECTORS(num_sectors);
448 }
449 
450 static int alloc_disk_sb(mdk_rdev_t * rdev)
451 {
452 	if (rdev->sb_page)
453 		MD_BUG();
454 
455 	rdev->sb_page = alloc_page(GFP_KERNEL);
456 	if (!rdev->sb_page) {
457 		printk(KERN_ALERT "md: out of memory.\n");
458 		return -ENOMEM;
459 	}
460 
461 	return 0;
462 }
463 
464 static void free_disk_sb(mdk_rdev_t * rdev)
465 {
466 	if (rdev->sb_page) {
467 		put_page(rdev->sb_page);
468 		rdev->sb_loaded = 0;
469 		rdev->sb_page = NULL;
470 		rdev->sb_start = 0;
471 		rdev->sectors = 0;
472 	}
473 }
474 
475 
476 static void super_written(struct bio *bio, int error)
477 {
478 	mdk_rdev_t *rdev = bio->bi_private;
479 	mddev_t *mddev = rdev->mddev;
480 
481 	if (error || !test_bit(BIO_UPTODATE, &bio->bi_flags)) {
482 		printk("md: super_written gets error=%d, uptodate=%d\n",
483 		       error, test_bit(BIO_UPTODATE, &bio->bi_flags));
484 		WARN_ON(test_bit(BIO_UPTODATE, &bio->bi_flags));
485 		md_error(mddev, rdev);
486 	}
487 
488 	if (atomic_dec_and_test(&mddev->pending_writes))
489 		wake_up(&mddev->sb_wait);
490 	bio_put(bio);
491 }
492 
493 static void super_written_barrier(struct bio *bio, int error)
494 {
495 	struct bio *bio2 = bio->bi_private;
496 	mdk_rdev_t *rdev = bio2->bi_private;
497 	mddev_t *mddev = rdev->mddev;
498 
499 	if (!test_bit(BIO_UPTODATE, &bio->bi_flags) &&
500 	    error == -EOPNOTSUPP) {
501 		unsigned long flags;
502 		/* barriers don't appear to be supported :-( */
503 		set_bit(BarriersNotsupp, &rdev->flags);
504 		mddev->barriers_work = 0;
505 		spin_lock_irqsave(&mddev->write_lock, flags);
506 		bio2->bi_next = mddev->biolist;
507 		mddev->biolist = bio2;
508 		spin_unlock_irqrestore(&mddev->write_lock, flags);
509 		wake_up(&mddev->sb_wait);
510 		bio_put(bio);
511 	} else {
512 		bio_put(bio2);
513 		bio->bi_private = rdev;
514 		super_written(bio, error);
515 	}
516 }
517 
518 void md_super_write(mddev_t *mddev, mdk_rdev_t *rdev,
519 		   sector_t sector, int size, struct page *page)
520 {
521 	/* write first size bytes of page to sector of rdev
522 	 * Increment mddev->pending_writes before returning
523 	 * and decrement it on completion, waking up sb_wait
524 	 * if zero is reached.
525 	 * If an error occurred, call md_error
526 	 *
527 	 * As we might need to resubmit the request if BIO_RW_BARRIER
528 	 * causes ENOTSUPP, we allocate a spare bio...
529 	 */
530 	struct bio *bio = bio_alloc(GFP_NOIO, 1);
531 	int rw = (1<<BIO_RW) | (1<<BIO_RW_SYNCIO) | (1<<BIO_RW_UNPLUG);
532 
533 	bio->bi_bdev = rdev->bdev;
534 	bio->bi_sector = sector;
535 	bio_add_page(bio, page, size, 0);
536 	bio->bi_private = rdev;
537 	bio->bi_end_io = super_written;
538 	bio->bi_rw = rw;
539 
540 	atomic_inc(&mddev->pending_writes);
541 	if (!test_bit(BarriersNotsupp, &rdev->flags)) {
542 		struct bio *rbio;
543 		rw |= (1<<BIO_RW_BARRIER);
544 		rbio = bio_clone(bio, GFP_NOIO);
545 		rbio->bi_private = bio;
546 		rbio->bi_end_io = super_written_barrier;
547 		submit_bio(rw, rbio);
548 	} else
549 		submit_bio(rw, bio);
550 }
551 
552 void md_super_wait(mddev_t *mddev)
553 {
554 	/* wait for all superblock writes that were scheduled to complete.
555 	 * if any had to be retried (due to BARRIER problems), retry them
556 	 */
557 	DEFINE_WAIT(wq);
558 	for(;;) {
559 		prepare_to_wait(&mddev->sb_wait, &wq, TASK_UNINTERRUPTIBLE);
560 		if (atomic_read(&mddev->pending_writes)==0)
561 			break;
562 		while (mddev->biolist) {
563 			struct bio *bio;
564 			spin_lock_irq(&mddev->write_lock);
565 			bio = mddev->biolist;
566 			mddev->biolist = bio->bi_next ;
567 			bio->bi_next = NULL;
568 			spin_unlock_irq(&mddev->write_lock);
569 			submit_bio(bio->bi_rw, bio);
570 		}
571 		schedule();
572 	}
573 	finish_wait(&mddev->sb_wait, &wq);
574 }
575 
576 static void bi_complete(struct bio *bio, int error)
577 {
578 	complete((struct completion*)bio->bi_private);
579 }
580 
581 int sync_page_io(struct block_device *bdev, sector_t sector, int size,
582 		   struct page *page, int rw)
583 {
584 	struct bio *bio = bio_alloc(GFP_NOIO, 1);
585 	struct completion event;
586 	int ret;
587 
588 	rw |= (1 << BIO_RW_SYNCIO) | (1 << BIO_RW_UNPLUG);
589 
590 	bio->bi_bdev = bdev;
591 	bio->bi_sector = sector;
592 	bio_add_page(bio, page, size, 0);
593 	init_completion(&event);
594 	bio->bi_private = &event;
595 	bio->bi_end_io = bi_complete;
596 	submit_bio(rw, bio);
597 	wait_for_completion(&event);
598 
599 	ret = test_bit(BIO_UPTODATE, &bio->bi_flags);
600 	bio_put(bio);
601 	return ret;
602 }
603 EXPORT_SYMBOL_GPL(sync_page_io);
604 
605 static int read_disk_sb(mdk_rdev_t * rdev, int size)
606 {
607 	char b[BDEVNAME_SIZE];
608 	if (!rdev->sb_page) {
609 		MD_BUG();
610 		return -EINVAL;
611 	}
612 	if (rdev->sb_loaded)
613 		return 0;
614 
615 
616 	if (!sync_page_io(rdev->bdev, rdev->sb_start, size, rdev->sb_page, READ))
617 		goto fail;
618 	rdev->sb_loaded = 1;
619 	return 0;
620 
621 fail:
622 	printk(KERN_WARNING "md: disabled device %s, could not read superblock.\n",
623 		bdevname(rdev->bdev,b));
624 	return -EINVAL;
625 }
626 
627 static int uuid_equal(mdp_super_t *sb1, mdp_super_t *sb2)
628 {
629 	return 	sb1->set_uuid0 == sb2->set_uuid0 &&
630 		sb1->set_uuid1 == sb2->set_uuid1 &&
631 		sb1->set_uuid2 == sb2->set_uuid2 &&
632 		sb1->set_uuid3 == sb2->set_uuid3;
633 }
634 
635 static int sb_equal(mdp_super_t *sb1, mdp_super_t *sb2)
636 {
637 	int ret;
638 	mdp_super_t *tmp1, *tmp2;
639 
640 	tmp1 = kmalloc(sizeof(*tmp1),GFP_KERNEL);
641 	tmp2 = kmalloc(sizeof(*tmp2),GFP_KERNEL);
642 
643 	if (!tmp1 || !tmp2) {
644 		ret = 0;
645 		printk(KERN_INFO "md.c sb_equal(): failed to allocate memory!\n");
646 		goto abort;
647 	}
648 
649 	*tmp1 = *sb1;
650 	*tmp2 = *sb2;
651 
652 	/*
653 	 * nr_disks is not constant
654 	 */
655 	tmp1->nr_disks = 0;
656 	tmp2->nr_disks = 0;
657 
658 	ret = (memcmp(tmp1, tmp2, MD_SB_GENERIC_CONSTANT_WORDS * 4) == 0);
659 abort:
660 	kfree(tmp1);
661 	kfree(tmp2);
662 	return ret;
663 }
664 
665 
666 static u32 md_csum_fold(u32 csum)
667 {
668 	csum = (csum & 0xffff) + (csum >> 16);
669 	return (csum & 0xffff) + (csum >> 16);
670 }
671 
672 static unsigned int calc_sb_csum(mdp_super_t * sb)
673 {
674 	u64 newcsum = 0;
675 	u32 *sb32 = (u32*)sb;
676 	int i;
677 	unsigned int disk_csum, csum;
678 
679 	disk_csum = sb->sb_csum;
680 	sb->sb_csum = 0;
681 
682 	for (i = 0; i < MD_SB_BYTES/4 ; i++)
683 		newcsum += sb32[i];
684 	csum = (newcsum & 0xffffffff) + (newcsum>>32);
685 
686 
687 #ifdef CONFIG_ALPHA
688 	/* This used to use csum_partial, which was wrong for several
689 	 * reasons including that different results are returned on
690 	 * different architectures.  It isn't critical that we get exactly
691 	 * the same return value as before (we always csum_fold before
692 	 * testing, and that removes any differences).  However as we
693 	 * know that csum_partial always returned a 16bit value on
694 	 * alphas, do a fold to maximise conformity to previous behaviour.
695 	 */
696 	sb->sb_csum = md_csum_fold(disk_csum);
697 #else
698 	sb->sb_csum = disk_csum;
699 #endif
700 	return csum;
701 }
702 
703 
704 /*
705  * Handle superblock details.
706  * We want to be able to handle multiple superblock formats
707  * so we have a common interface to them all, and an array of
708  * different handlers.
709  * We rely on user-space to write the initial superblock, and support
710  * reading and updating of superblocks.
711  * Interface methods are:
712  *   int load_super(mdk_rdev_t *dev, mdk_rdev_t *refdev, int minor_version)
713  *      loads and validates a superblock on dev.
714  *      if refdev != NULL, compare superblocks on both devices
715  *    Return:
716  *      0 - dev has a superblock that is compatible with refdev
717  *      1 - dev has a superblock that is compatible and newer than refdev
718  *          so dev should be used as the refdev in future
719  *     -EINVAL superblock incompatible or invalid
720  *     -othererror e.g. -EIO
721  *
722  *   int validate_super(mddev_t *mddev, mdk_rdev_t *dev)
723  *      Verify that dev is acceptable into mddev.
724  *       The first time, mddev->raid_disks will be 0, and data from
725  *       dev should be merged in.  Subsequent calls check that dev
726  *       is new enough.  Return 0 or -EINVAL
727  *
728  *   void sync_super(mddev_t *mddev, mdk_rdev_t *dev)
729  *     Update the superblock for rdev with data in mddev
730  *     This does not write to disc.
731  *
732  */
733 
734 struct super_type  {
735 	char		    *name;
736 	struct module	    *owner;
737 	int		    (*load_super)(mdk_rdev_t *rdev, mdk_rdev_t *refdev,
738 					  int minor_version);
739 	int		    (*validate_super)(mddev_t *mddev, mdk_rdev_t *rdev);
740 	void		    (*sync_super)(mddev_t *mddev, mdk_rdev_t *rdev);
741 	unsigned long long  (*rdev_size_change)(mdk_rdev_t *rdev,
742 						sector_t num_sectors);
743 };
744 
745 /*
746  * Check that the given mddev has no bitmap.
747  *
748  * This function is called from the run method of all personalities that do not
749  * support bitmaps. It prints an error message and returns non-zero if mddev
750  * has a bitmap. Otherwise, it returns 0.
751  *
752  */
753 int md_check_no_bitmap(mddev_t *mddev)
754 {
755 	if (!mddev->bitmap_file && !mddev->bitmap_offset)
756 		return 0;
757 	printk(KERN_ERR "%s: bitmaps are not supported for %s\n",
758 		mdname(mddev), mddev->pers->name);
759 	return 1;
760 }
761 EXPORT_SYMBOL(md_check_no_bitmap);
762 
763 /*
764  * load_super for 0.90.0
765  */
766 static int super_90_load(mdk_rdev_t *rdev, mdk_rdev_t *refdev, int minor_version)
767 {
768 	char b[BDEVNAME_SIZE], b2[BDEVNAME_SIZE];
769 	mdp_super_t *sb;
770 	int ret;
771 
772 	/*
773 	 * Calculate the position of the superblock (512byte sectors),
774 	 * it's at the end of the disk.
775 	 *
776 	 * It also happens to be a multiple of 4Kb.
777 	 */
778 	rdev->sb_start = calc_dev_sboffset(rdev->bdev);
779 
780 	ret = read_disk_sb(rdev, MD_SB_BYTES);
781 	if (ret) return ret;
782 
783 	ret = -EINVAL;
784 
785 	bdevname(rdev->bdev, b);
786 	sb = (mdp_super_t*)page_address(rdev->sb_page);
787 
788 	if (sb->md_magic != MD_SB_MAGIC) {
789 		printk(KERN_ERR "md: invalid raid superblock magic on %s\n",
790 		       b);
791 		goto abort;
792 	}
793 
794 	if (sb->major_version != 0 ||
795 	    sb->minor_version < 90 ||
796 	    sb->minor_version > 91) {
797 		printk(KERN_WARNING "Bad version number %d.%d on %s\n",
798 			sb->major_version, sb->minor_version,
799 			b);
800 		goto abort;
801 	}
802 
803 	if (sb->raid_disks <= 0)
804 		goto abort;
805 
806 	if (md_csum_fold(calc_sb_csum(sb)) != md_csum_fold(sb->sb_csum)) {
807 		printk(KERN_WARNING "md: invalid superblock checksum on %s\n",
808 			b);
809 		goto abort;
810 	}
811 
812 	rdev->preferred_minor = sb->md_minor;
813 	rdev->data_offset = 0;
814 	rdev->sb_size = MD_SB_BYTES;
815 
816 	if (sb->level == LEVEL_MULTIPATH)
817 		rdev->desc_nr = -1;
818 	else
819 		rdev->desc_nr = sb->this_disk.number;
820 
821 	if (!refdev) {
822 		ret = 1;
823 	} else {
824 		__u64 ev1, ev2;
825 		mdp_super_t *refsb = (mdp_super_t*)page_address(refdev->sb_page);
826 		if (!uuid_equal(refsb, sb)) {
827 			printk(KERN_WARNING "md: %s has different UUID to %s\n",
828 				b, bdevname(refdev->bdev,b2));
829 			goto abort;
830 		}
831 		if (!sb_equal(refsb, sb)) {
832 			printk(KERN_WARNING "md: %s has same UUID"
833 			       " but different superblock to %s\n",
834 			       b, bdevname(refdev->bdev, b2));
835 			goto abort;
836 		}
837 		ev1 = md_event(sb);
838 		ev2 = md_event(refsb);
839 		if (ev1 > ev2)
840 			ret = 1;
841 		else
842 			ret = 0;
843 	}
844 	rdev->sectors = rdev->sb_start;
845 
846 	if (rdev->sectors < sb->size * 2 && sb->level > 1)
847 		/* "this cannot possibly happen" ... */
848 		ret = -EINVAL;
849 
850  abort:
851 	return ret;
852 }
853 
854 /*
855  * validate_super for 0.90.0
856  */
857 static int super_90_validate(mddev_t *mddev, mdk_rdev_t *rdev)
858 {
859 	mdp_disk_t *desc;
860 	mdp_super_t *sb = (mdp_super_t *)page_address(rdev->sb_page);
861 	__u64 ev1 = md_event(sb);
862 
863 	rdev->raid_disk = -1;
864 	clear_bit(Faulty, &rdev->flags);
865 	clear_bit(In_sync, &rdev->flags);
866 	clear_bit(WriteMostly, &rdev->flags);
867 	clear_bit(BarriersNotsupp, &rdev->flags);
868 
869 	if (mddev->raid_disks == 0) {
870 		mddev->major_version = 0;
871 		mddev->minor_version = sb->minor_version;
872 		mddev->patch_version = sb->patch_version;
873 		mddev->external = 0;
874 		mddev->chunk_sectors = sb->chunk_size >> 9;
875 		mddev->ctime = sb->ctime;
876 		mddev->utime = sb->utime;
877 		mddev->level = sb->level;
878 		mddev->clevel[0] = 0;
879 		mddev->layout = sb->layout;
880 		mddev->raid_disks = sb->raid_disks;
881 		mddev->dev_sectors = sb->size * 2;
882 		mddev->events = ev1;
883 		mddev->bitmap_offset = 0;
884 		mddev->default_bitmap_offset = MD_SB_BYTES >> 9;
885 
886 		if (mddev->minor_version >= 91) {
887 			mddev->reshape_position = sb->reshape_position;
888 			mddev->delta_disks = sb->delta_disks;
889 			mddev->new_level = sb->new_level;
890 			mddev->new_layout = sb->new_layout;
891 			mddev->new_chunk_sectors = sb->new_chunk >> 9;
892 		} else {
893 			mddev->reshape_position = MaxSector;
894 			mddev->delta_disks = 0;
895 			mddev->new_level = mddev->level;
896 			mddev->new_layout = mddev->layout;
897 			mddev->new_chunk_sectors = mddev->chunk_sectors;
898 		}
899 
900 		if (sb->state & (1<<MD_SB_CLEAN))
901 			mddev->recovery_cp = MaxSector;
902 		else {
903 			if (sb->events_hi == sb->cp_events_hi &&
904 				sb->events_lo == sb->cp_events_lo) {
905 				mddev->recovery_cp = sb->recovery_cp;
906 			} else
907 				mddev->recovery_cp = 0;
908 		}
909 
910 		memcpy(mddev->uuid+0, &sb->set_uuid0, 4);
911 		memcpy(mddev->uuid+4, &sb->set_uuid1, 4);
912 		memcpy(mddev->uuid+8, &sb->set_uuid2, 4);
913 		memcpy(mddev->uuid+12,&sb->set_uuid3, 4);
914 
915 		mddev->max_disks = MD_SB_DISKS;
916 
917 		if (sb->state & (1<<MD_SB_BITMAP_PRESENT) &&
918 		    mddev->bitmap_file == NULL)
919 			mddev->bitmap_offset = mddev->default_bitmap_offset;
920 
921 	} else if (mddev->pers == NULL) {
922 		/* Insist on good event counter while assembling */
923 		++ev1;
924 		if (ev1 < mddev->events)
925 			return -EINVAL;
926 	} else if (mddev->bitmap) {
927 		/* if adding to array with a bitmap, then we can accept an
928 		 * older device ... but not too old.
929 		 */
930 		if (ev1 < mddev->bitmap->events_cleared)
931 			return 0;
932 	} else {
933 		if (ev1 < mddev->events)
934 			/* just a hot-add of a new device, leave raid_disk at -1 */
935 			return 0;
936 	}
937 
938 	if (mddev->level != LEVEL_MULTIPATH) {
939 		desc = sb->disks + rdev->desc_nr;
940 
941 		if (desc->state & (1<<MD_DISK_FAULTY))
942 			set_bit(Faulty, &rdev->flags);
943 		else if (desc->state & (1<<MD_DISK_SYNC) /* &&
944 			    desc->raid_disk < mddev->raid_disks */) {
945 			set_bit(In_sync, &rdev->flags);
946 			rdev->raid_disk = desc->raid_disk;
947 		} else if (desc->state & (1<<MD_DISK_ACTIVE)) {
948 			/* active but not in sync implies recovery up to
949 			 * reshape position.  We don't know exactly where
950 			 * that is, so set to zero for now */
951 			if (mddev->minor_version >= 91) {
952 				rdev->recovery_offset = 0;
953 				rdev->raid_disk = desc->raid_disk;
954 			}
955 		}
956 		if (desc->state & (1<<MD_DISK_WRITEMOSTLY))
957 			set_bit(WriteMostly, &rdev->flags);
958 	} else /* MULTIPATH are always insync */
959 		set_bit(In_sync, &rdev->flags);
960 	return 0;
961 }
962 
963 /*
964  * sync_super for 0.90.0
965  */
966 static void super_90_sync(mddev_t *mddev, mdk_rdev_t *rdev)
967 {
968 	mdp_super_t *sb;
969 	mdk_rdev_t *rdev2;
970 	int next_spare = mddev->raid_disks;
971 
972 
973 	/* make rdev->sb match mddev data..
974 	 *
975 	 * 1/ zero out disks
976 	 * 2/ Add info for each disk, keeping track of highest desc_nr (next_spare);
977 	 * 3/ any empty disks < next_spare become removed
978 	 *
979 	 * disks[0] gets initialised to REMOVED because
980 	 * we cannot be sure from other fields if it has
981 	 * been initialised or not.
982 	 */
983 	int i;
984 	int active=0, working=0,failed=0,spare=0,nr_disks=0;
985 
986 	rdev->sb_size = MD_SB_BYTES;
987 
988 	sb = (mdp_super_t*)page_address(rdev->sb_page);
989 
990 	memset(sb, 0, sizeof(*sb));
991 
992 	sb->md_magic = MD_SB_MAGIC;
993 	sb->major_version = mddev->major_version;
994 	sb->patch_version = mddev->patch_version;
995 	sb->gvalid_words  = 0; /* ignored */
996 	memcpy(&sb->set_uuid0, mddev->uuid+0, 4);
997 	memcpy(&sb->set_uuid1, mddev->uuid+4, 4);
998 	memcpy(&sb->set_uuid2, mddev->uuid+8, 4);
999 	memcpy(&sb->set_uuid3, mddev->uuid+12,4);
1000 
1001 	sb->ctime = mddev->ctime;
1002 	sb->level = mddev->level;
1003 	sb->size = mddev->dev_sectors / 2;
1004 	sb->raid_disks = mddev->raid_disks;
1005 	sb->md_minor = mddev->md_minor;
1006 	sb->not_persistent = 0;
1007 	sb->utime = mddev->utime;
1008 	sb->state = 0;
1009 	sb->events_hi = (mddev->events>>32);
1010 	sb->events_lo = (u32)mddev->events;
1011 
1012 	if (mddev->reshape_position == MaxSector)
1013 		sb->minor_version = 90;
1014 	else {
1015 		sb->minor_version = 91;
1016 		sb->reshape_position = mddev->reshape_position;
1017 		sb->new_level = mddev->new_level;
1018 		sb->delta_disks = mddev->delta_disks;
1019 		sb->new_layout = mddev->new_layout;
1020 		sb->new_chunk = mddev->new_chunk_sectors << 9;
1021 	}
1022 	mddev->minor_version = sb->minor_version;
1023 	if (mddev->in_sync)
1024 	{
1025 		sb->recovery_cp = mddev->recovery_cp;
1026 		sb->cp_events_hi = (mddev->events>>32);
1027 		sb->cp_events_lo = (u32)mddev->events;
1028 		if (mddev->recovery_cp == MaxSector)
1029 			sb->state = (1<< MD_SB_CLEAN);
1030 	} else
1031 		sb->recovery_cp = 0;
1032 
1033 	sb->layout = mddev->layout;
1034 	sb->chunk_size = mddev->chunk_sectors << 9;
1035 
1036 	if (mddev->bitmap && mddev->bitmap_file == NULL)
1037 		sb->state |= (1<<MD_SB_BITMAP_PRESENT);
1038 
1039 	sb->disks[0].state = (1<<MD_DISK_REMOVED);
1040 	list_for_each_entry(rdev2, &mddev->disks, same_set) {
1041 		mdp_disk_t *d;
1042 		int desc_nr;
1043 		int is_active = test_bit(In_sync, &rdev2->flags);
1044 
1045 		if (rdev2->raid_disk >= 0 &&
1046 		    sb->minor_version >= 91)
1047 			/* we have nowhere to store the recovery_offset,
1048 			 * but if it is not below the reshape_position,
1049 			 * we can piggy-back on that.
1050 			 */
1051 			is_active = 1;
1052 		if (rdev2->raid_disk < 0 ||
1053 		    test_bit(Faulty, &rdev2->flags))
1054 			is_active = 0;
1055 		if (is_active)
1056 			desc_nr = rdev2->raid_disk;
1057 		else
1058 			desc_nr = next_spare++;
1059 		rdev2->desc_nr = desc_nr;
1060 		d = &sb->disks[rdev2->desc_nr];
1061 		nr_disks++;
1062 		d->number = rdev2->desc_nr;
1063 		d->major = MAJOR(rdev2->bdev->bd_dev);
1064 		d->minor = MINOR(rdev2->bdev->bd_dev);
1065 		if (is_active)
1066 			d->raid_disk = rdev2->raid_disk;
1067 		else
1068 			d->raid_disk = rdev2->desc_nr; /* compatibility */
1069 		if (test_bit(Faulty, &rdev2->flags))
1070 			d->state = (1<<MD_DISK_FAULTY);
1071 		else if (is_active) {
1072 			d->state = (1<<MD_DISK_ACTIVE);
1073 			if (test_bit(In_sync, &rdev2->flags))
1074 				d->state |= (1<<MD_DISK_SYNC);
1075 			active++;
1076 			working++;
1077 		} else {
1078 			d->state = 0;
1079 			spare++;
1080 			working++;
1081 		}
1082 		if (test_bit(WriteMostly, &rdev2->flags))
1083 			d->state |= (1<<MD_DISK_WRITEMOSTLY);
1084 	}
1085 	/* now set the "removed" and "faulty" bits on any missing devices */
1086 	for (i=0 ; i < mddev->raid_disks ; i++) {
1087 		mdp_disk_t *d = &sb->disks[i];
1088 		if (d->state == 0 && d->number == 0) {
1089 			d->number = i;
1090 			d->raid_disk = i;
1091 			d->state = (1<<MD_DISK_REMOVED);
1092 			d->state |= (1<<MD_DISK_FAULTY);
1093 			failed++;
1094 		}
1095 	}
1096 	sb->nr_disks = nr_disks;
1097 	sb->active_disks = active;
1098 	sb->working_disks = working;
1099 	sb->failed_disks = failed;
1100 	sb->spare_disks = spare;
1101 
1102 	sb->this_disk = sb->disks[rdev->desc_nr];
1103 	sb->sb_csum = calc_sb_csum(sb);
1104 }
1105 
1106 /*
1107  * rdev_size_change for 0.90.0
1108  */
1109 static unsigned long long
1110 super_90_rdev_size_change(mdk_rdev_t *rdev, sector_t num_sectors)
1111 {
1112 	if (num_sectors && num_sectors < rdev->mddev->dev_sectors)
1113 		return 0; /* component must fit device */
1114 	if (rdev->mddev->bitmap_offset)
1115 		return 0; /* can't move bitmap */
1116 	rdev->sb_start = calc_dev_sboffset(rdev->bdev);
1117 	if (!num_sectors || num_sectors > rdev->sb_start)
1118 		num_sectors = rdev->sb_start;
1119 	md_super_write(rdev->mddev, rdev, rdev->sb_start, rdev->sb_size,
1120 		       rdev->sb_page);
1121 	md_super_wait(rdev->mddev);
1122 	return num_sectors / 2; /* kB for sysfs */
1123 }
1124 
1125 
1126 /*
1127  * version 1 superblock
1128  */
1129 
1130 static __le32 calc_sb_1_csum(struct mdp_superblock_1 * sb)
1131 {
1132 	__le32 disk_csum;
1133 	u32 csum;
1134 	unsigned long long newcsum;
1135 	int size = 256 + le32_to_cpu(sb->max_dev)*2;
1136 	__le32 *isuper = (__le32*)sb;
1137 	int i;
1138 
1139 	disk_csum = sb->sb_csum;
1140 	sb->sb_csum = 0;
1141 	newcsum = 0;
1142 	for (i=0; size>=4; size -= 4 )
1143 		newcsum += le32_to_cpu(*isuper++);
1144 
1145 	if (size == 2)
1146 		newcsum += le16_to_cpu(*(__le16*) isuper);
1147 
1148 	csum = (newcsum & 0xffffffff) + (newcsum >> 32);
1149 	sb->sb_csum = disk_csum;
1150 	return cpu_to_le32(csum);
1151 }
1152 
1153 static int super_1_load(mdk_rdev_t *rdev, mdk_rdev_t *refdev, int minor_version)
1154 {
1155 	struct mdp_superblock_1 *sb;
1156 	int ret;
1157 	sector_t sb_start;
1158 	char b[BDEVNAME_SIZE], b2[BDEVNAME_SIZE];
1159 	int bmask;
1160 
1161 	/*
1162 	 * Calculate the position of the superblock in 512byte sectors.
1163 	 * It is always aligned to a 4K boundary and
1164 	 * depeding on minor_version, it can be:
1165 	 * 0: At least 8K, but less than 12K, from end of device
1166 	 * 1: At start of device
1167 	 * 2: 4K from start of device.
1168 	 */
1169 	switch(minor_version) {
1170 	case 0:
1171 		sb_start = rdev->bdev->bd_inode->i_size >> 9;
1172 		sb_start -= 8*2;
1173 		sb_start &= ~(sector_t)(4*2-1);
1174 		break;
1175 	case 1:
1176 		sb_start = 0;
1177 		break;
1178 	case 2:
1179 		sb_start = 8;
1180 		break;
1181 	default:
1182 		return -EINVAL;
1183 	}
1184 	rdev->sb_start = sb_start;
1185 
1186 	/* superblock is rarely larger than 1K, but it can be larger,
1187 	 * and it is safe to read 4k, so we do that
1188 	 */
1189 	ret = read_disk_sb(rdev, 4096);
1190 	if (ret) return ret;
1191 
1192 
1193 	sb = (struct mdp_superblock_1*)page_address(rdev->sb_page);
1194 
1195 	if (sb->magic != cpu_to_le32(MD_SB_MAGIC) ||
1196 	    sb->major_version != cpu_to_le32(1) ||
1197 	    le32_to_cpu(sb->max_dev) > (4096-256)/2 ||
1198 	    le64_to_cpu(sb->super_offset) != rdev->sb_start ||
1199 	    (le32_to_cpu(sb->feature_map) & ~MD_FEATURE_ALL) != 0)
1200 		return -EINVAL;
1201 
1202 	if (calc_sb_1_csum(sb) != sb->sb_csum) {
1203 		printk("md: invalid superblock checksum on %s\n",
1204 			bdevname(rdev->bdev,b));
1205 		return -EINVAL;
1206 	}
1207 	if (le64_to_cpu(sb->data_size) < 10) {
1208 		printk("md: data_size too small on %s\n",
1209 		       bdevname(rdev->bdev,b));
1210 		return -EINVAL;
1211 	}
1212 
1213 	rdev->preferred_minor = 0xffff;
1214 	rdev->data_offset = le64_to_cpu(sb->data_offset);
1215 	atomic_set(&rdev->corrected_errors, le32_to_cpu(sb->cnt_corrected_read));
1216 
1217 	rdev->sb_size = le32_to_cpu(sb->max_dev) * 2 + 256;
1218 	bmask = queue_logical_block_size(rdev->bdev->bd_disk->queue)-1;
1219 	if (rdev->sb_size & bmask)
1220 		rdev->sb_size = (rdev->sb_size | bmask) + 1;
1221 
1222 	if (minor_version
1223 	    && rdev->data_offset < sb_start + (rdev->sb_size/512))
1224 		return -EINVAL;
1225 
1226 	if (sb->level == cpu_to_le32(LEVEL_MULTIPATH))
1227 		rdev->desc_nr = -1;
1228 	else
1229 		rdev->desc_nr = le32_to_cpu(sb->dev_number);
1230 
1231 	if (!refdev) {
1232 		ret = 1;
1233 	} else {
1234 		__u64 ev1, ev2;
1235 		struct mdp_superblock_1 *refsb =
1236 			(struct mdp_superblock_1*)page_address(refdev->sb_page);
1237 
1238 		if (memcmp(sb->set_uuid, refsb->set_uuid, 16) != 0 ||
1239 		    sb->level != refsb->level ||
1240 		    sb->layout != refsb->layout ||
1241 		    sb->chunksize != refsb->chunksize) {
1242 			printk(KERN_WARNING "md: %s has strangely different"
1243 				" superblock to %s\n",
1244 				bdevname(rdev->bdev,b),
1245 				bdevname(refdev->bdev,b2));
1246 			return -EINVAL;
1247 		}
1248 		ev1 = le64_to_cpu(sb->events);
1249 		ev2 = le64_to_cpu(refsb->events);
1250 
1251 		if (ev1 > ev2)
1252 			ret = 1;
1253 		else
1254 			ret = 0;
1255 	}
1256 	if (minor_version)
1257 		rdev->sectors = (rdev->bdev->bd_inode->i_size >> 9) -
1258 			le64_to_cpu(sb->data_offset);
1259 	else
1260 		rdev->sectors = rdev->sb_start;
1261 	if (rdev->sectors < le64_to_cpu(sb->data_size))
1262 		return -EINVAL;
1263 	rdev->sectors = le64_to_cpu(sb->data_size);
1264 	if (le64_to_cpu(sb->size) > rdev->sectors)
1265 		return -EINVAL;
1266 	return ret;
1267 }
1268 
1269 static int super_1_validate(mddev_t *mddev, mdk_rdev_t *rdev)
1270 {
1271 	struct mdp_superblock_1 *sb = (struct mdp_superblock_1*)page_address(rdev->sb_page);
1272 	__u64 ev1 = le64_to_cpu(sb->events);
1273 
1274 	rdev->raid_disk = -1;
1275 	clear_bit(Faulty, &rdev->flags);
1276 	clear_bit(In_sync, &rdev->flags);
1277 	clear_bit(WriteMostly, &rdev->flags);
1278 	clear_bit(BarriersNotsupp, &rdev->flags);
1279 
1280 	if (mddev->raid_disks == 0) {
1281 		mddev->major_version = 1;
1282 		mddev->patch_version = 0;
1283 		mddev->external = 0;
1284 		mddev->chunk_sectors = le32_to_cpu(sb->chunksize);
1285 		mddev->ctime = le64_to_cpu(sb->ctime) & ((1ULL << 32)-1);
1286 		mddev->utime = le64_to_cpu(sb->utime) & ((1ULL << 32)-1);
1287 		mddev->level = le32_to_cpu(sb->level);
1288 		mddev->clevel[0] = 0;
1289 		mddev->layout = le32_to_cpu(sb->layout);
1290 		mddev->raid_disks = le32_to_cpu(sb->raid_disks);
1291 		mddev->dev_sectors = le64_to_cpu(sb->size);
1292 		mddev->events = ev1;
1293 		mddev->bitmap_offset = 0;
1294 		mddev->default_bitmap_offset = 1024 >> 9;
1295 
1296 		mddev->recovery_cp = le64_to_cpu(sb->resync_offset);
1297 		memcpy(mddev->uuid, sb->set_uuid, 16);
1298 
1299 		mddev->max_disks =  (4096-256)/2;
1300 
1301 		if ((le32_to_cpu(sb->feature_map) & MD_FEATURE_BITMAP_OFFSET) &&
1302 		    mddev->bitmap_file == NULL )
1303 			mddev->bitmap_offset = (__s32)le32_to_cpu(sb->bitmap_offset);
1304 
1305 		if ((le32_to_cpu(sb->feature_map) & MD_FEATURE_RESHAPE_ACTIVE)) {
1306 			mddev->reshape_position = le64_to_cpu(sb->reshape_position);
1307 			mddev->delta_disks = le32_to_cpu(sb->delta_disks);
1308 			mddev->new_level = le32_to_cpu(sb->new_level);
1309 			mddev->new_layout = le32_to_cpu(sb->new_layout);
1310 			mddev->new_chunk_sectors = le32_to_cpu(sb->new_chunk);
1311 		} else {
1312 			mddev->reshape_position = MaxSector;
1313 			mddev->delta_disks = 0;
1314 			mddev->new_level = mddev->level;
1315 			mddev->new_layout = mddev->layout;
1316 			mddev->new_chunk_sectors = mddev->chunk_sectors;
1317 		}
1318 
1319 	} else if (mddev->pers == NULL) {
1320 		/* Insist of good event counter while assembling */
1321 		++ev1;
1322 		if (ev1 < mddev->events)
1323 			return -EINVAL;
1324 	} else if (mddev->bitmap) {
1325 		/* If adding to array with a bitmap, then we can accept an
1326 		 * older device, but not too old.
1327 		 */
1328 		if (ev1 < mddev->bitmap->events_cleared)
1329 			return 0;
1330 	} else {
1331 		if (ev1 < mddev->events)
1332 			/* just a hot-add of a new device, leave raid_disk at -1 */
1333 			return 0;
1334 	}
1335 	if (mddev->level != LEVEL_MULTIPATH) {
1336 		int role;
1337 		if (rdev->desc_nr < 0 ||
1338 		    rdev->desc_nr >= le32_to_cpu(sb->max_dev)) {
1339 			role = 0xffff;
1340 			rdev->desc_nr = -1;
1341 		} else
1342 			role = le16_to_cpu(sb->dev_roles[rdev->desc_nr]);
1343 		switch(role) {
1344 		case 0xffff: /* spare */
1345 			break;
1346 		case 0xfffe: /* faulty */
1347 			set_bit(Faulty, &rdev->flags);
1348 			break;
1349 		default:
1350 			if ((le32_to_cpu(sb->feature_map) &
1351 			     MD_FEATURE_RECOVERY_OFFSET))
1352 				rdev->recovery_offset = le64_to_cpu(sb->recovery_offset);
1353 			else
1354 				set_bit(In_sync, &rdev->flags);
1355 			rdev->raid_disk = role;
1356 			break;
1357 		}
1358 		if (sb->devflags & WriteMostly1)
1359 			set_bit(WriteMostly, &rdev->flags);
1360 	} else /* MULTIPATH are always insync */
1361 		set_bit(In_sync, &rdev->flags);
1362 
1363 	return 0;
1364 }
1365 
1366 static void super_1_sync(mddev_t *mddev, mdk_rdev_t *rdev)
1367 {
1368 	struct mdp_superblock_1 *sb;
1369 	mdk_rdev_t *rdev2;
1370 	int max_dev, i;
1371 	/* make rdev->sb match mddev and rdev data. */
1372 
1373 	sb = (struct mdp_superblock_1*)page_address(rdev->sb_page);
1374 
1375 	sb->feature_map = 0;
1376 	sb->pad0 = 0;
1377 	sb->recovery_offset = cpu_to_le64(0);
1378 	memset(sb->pad1, 0, sizeof(sb->pad1));
1379 	memset(sb->pad2, 0, sizeof(sb->pad2));
1380 	memset(sb->pad3, 0, sizeof(sb->pad3));
1381 
1382 	sb->utime = cpu_to_le64((__u64)mddev->utime);
1383 	sb->events = cpu_to_le64(mddev->events);
1384 	if (mddev->in_sync)
1385 		sb->resync_offset = cpu_to_le64(mddev->recovery_cp);
1386 	else
1387 		sb->resync_offset = cpu_to_le64(0);
1388 
1389 	sb->cnt_corrected_read = cpu_to_le32(atomic_read(&rdev->corrected_errors));
1390 
1391 	sb->raid_disks = cpu_to_le32(mddev->raid_disks);
1392 	sb->size = cpu_to_le64(mddev->dev_sectors);
1393 	sb->chunksize = cpu_to_le32(mddev->chunk_sectors);
1394 	sb->level = cpu_to_le32(mddev->level);
1395 	sb->layout = cpu_to_le32(mddev->layout);
1396 
1397 	if (mddev->bitmap && mddev->bitmap_file == NULL) {
1398 		sb->bitmap_offset = cpu_to_le32((__u32)mddev->bitmap_offset);
1399 		sb->feature_map = cpu_to_le32(MD_FEATURE_BITMAP_OFFSET);
1400 	}
1401 
1402 	if (rdev->raid_disk >= 0 &&
1403 	    !test_bit(In_sync, &rdev->flags)) {
1404 		if (rdev->recovery_offset > 0) {
1405 			sb->feature_map |=
1406 				cpu_to_le32(MD_FEATURE_RECOVERY_OFFSET);
1407 			sb->recovery_offset =
1408 				cpu_to_le64(rdev->recovery_offset);
1409 		}
1410 	}
1411 
1412 	if (mddev->reshape_position != MaxSector) {
1413 		sb->feature_map |= cpu_to_le32(MD_FEATURE_RESHAPE_ACTIVE);
1414 		sb->reshape_position = cpu_to_le64(mddev->reshape_position);
1415 		sb->new_layout = cpu_to_le32(mddev->new_layout);
1416 		sb->delta_disks = cpu_to_le32(mddev->delta_disks);
1417 		sb->new_level = cpu_to_le32(mddev->new_level);
1418 		sb->new_chunk = cpu_to_le32(mddev->new_chunk_sectors);
1419 	}
1420 
1421 	max_dev = 0;
1422 	list_for_each_entry(rdev2, &mddev->disks, same_set)
1423 		if (rdev2->desc_nr+1 > max_dev)
1424 			max_dev = rdev2->desc_nr+1;
1425 
1426 	if (max_dev > le32_to_cpu(sb->max_dev)) {
1427 		int bmask;
1428 		sb->max_dev = cpu_to_le32(max_dev);
1429 		rdev->sb_size = max_dev * 2 + 256;
1430 		bmask = queue_logical_block_size(rdev->bdev->bd_disk->queue)-1;
1431 		if (rdev->sb_size & bmask)
1432 			rdev->sb_size = (rdev->sb_size | bmask) + 1;
1433 	}
1434 	for (i=0; i<max_dev;i++)
1435 		sb->dev_roles[i] = cpu_to_le16(0xfffe);
1436 
1437 	list_for_each_entry(rdev2, &mddev->disks, same_set) {
1438 		i = rdev2->desc_nr;
1439 		if (test_bit(Faulty, &rdev2->flags))
1440 			sb->dev_roles[i] = cpu_to_le16(0xfffe);
1441 		else if (test_bit(In_sync, &rdev2->flags))
1442 			sb->dev_roles[i] = cpu_to_le16(rdev2->raid_disk);
1443 		else if (rdev2->raid_disk >= 0 && rdev2->recovery_offset > 0)
1444 			sb->dev_roles[i] = cpu_to_le16(rdev2->raid_disk);
1445 		else
1446 			sb->dev_roles[i] = cpu_to_le16(0xffff);
1447 	}
1448 
1449 	sb->sb_csum = calc_sb_1_csum(sb);
1450 }
1451 
1452 static unsigned long long
1453 super_1_rdev_size_change(mdk_rdev_t *rdev, sector_t num_sectors)
1454 {
1455 	struct mdp_superblock_1 *sb;
1456 	sector_t max_sectors;
1457 	if (num_sectors && num_sectors < rdev->mddev->dev_sectors)
1458 		return 0; /* component must fit device */
1459 	if (rdev->sb_start < rdev->data_offset) {
1460 		/* minor versions 1 and 2; superblock before data */
1461 		max_sectors = rdev->bdev->bd_inode->i_size >> 9;
1462 		max_sectors -= rdev->data_offset;
1463 		if (!num_sectors || num_sectors > max_sectors)
1464 			num_sectors = max_sectors;
1465 	} else if (rdev->mddev->bitmap_offset) {
1466 		/* minor version 0 with bitmap we can't move */
1467 		return 0;
1468 	} else {
1469 		/* minor version 0; superblock after data */
1470 		sector_t sb_start;
1471 		sb_start = (rdev->bdev->bd_inode->i_size >> 9) - 8*2;
1472 		sb_start &= ~(sector_t)(4*2 - 1);
1473 		max_sectors = rdev->sectors + sb_start - rdev->sb_start;
1474 		if (!num_sectors || num_sectors > max_sectors)
1475 			num_sectors = max_sectors;
1476 		rdev->sb_start = sb_start;
1477 	}
1478 	sb = (struct mdp_superblock_1 *) page_address(rdev->sb_page);
1479 	sb->data_size = cpu_to_le64(num_sectors);
1480 	sb->super_offset = rdev->sb_start;
1481 	sb->sb_csum = calc_sb_1_csum(sb);
1482 	md_super_write(rdev->mddev, rdev, rdev->sb_start, rdev->sb_size,
1483 		       rdev->sb_page);
1484 	md_super_wait(rdev->mddev);
1485 	return num_sectors / 2; /* kB for sysfs */
1486 }
1487 
1488 static struct super_type super_types[] = {
1489 	[0] = {
1490 		.name	= "0.90.0",
1491 		.owner	= THIS_MODULE,
1492 		.load_super	    = super_90_load,
1493 		.validate_super	    = super_90_validate,
1494 		.sync_super	    = super_90_sync,
1495 		.rdev_size_change   = super_90_rdev_size_change,
1496 	},
1497 	[1] = {
1498 		.name	= "md-1",
1499 		.owner	= THIS_MODULE,
1500 		.load_super	    = super_1_load,
1501 		.validate_super	    = super_1_validate,
1502 		.sync_super	    = super_1_sync,
1503 		.rdev_size_change   = super_1_rdev_size_change,
1504 	},
1505 };
1506 
1507 static int match_mddev_units(mddev_t *mddev1, mddev_t *mddev2)
1508 {
1509 	mdk_rdev_t *rdev, *rdev2;
1510 
1511 	rcu_read_lock();
1512 	rdev_for_each_rcu(rdev, mddev1)
1513 		rdev_for_each_rcu(rdev2, mddev2)
1514 			if (rdev->bdev->bd_contains ==
1515 			    rdev2->bdev->bd_contains) {
1516 				rcu_read_unlock();
1517 				return 1;
1518 			}
1519 	rcu_read_unlock();
1520 	return 0;
1521 }
1522 
1523 static LIST_HEAD(pending_raid_disks);
1524 
1525 /*
1526  * Try to register data integrity profile for an mddev
1527  *
1528  * This is called when an array is started and after a disk has been kicked
1529  * from the array. It only succeeds if all working and active component devices
1530  * are integrity capable with matching profiles.
1531  */
1532 int md_integrity_register(mddev_t *mddev)
1533 {
1534 	mdk_rdev_t *rdev, *reference = NULL;
1535 
1536 	if (list_empty(&mddev->disks))
1537 		return 0; /* nothing to do */
1538 	if (blk_get_integrity(mddev->gendisk))
1539 		return 0; /* already registered */
1540 	list_for_each_entry(rdev, &mddev->disks, same_set) {
1541 		/* skip spares and non-functional disks */
1542 		if (test_bit(Faulty, &rdev->flags))
1543 			continue;
1544 		if (rdev->raid_disk < 0)
1545 			continue;
1546 		/*
1547 		 * If at least one rdev is not integrity capable, we can not
1548 		 * enable data integrity for the md device.
1549 		 */
1550 		if (!bdev_get_integrity(rdev->bdev))
1551 			return -EINVAL;
1552 		if (!reference) {
1553 			/* Use the first rdev as the reference */
1554 			reference = rdev;
1555 			continue;
1556 		}
1557 		/* does this rdev's profile match the reference profile? */
1558 		if (blk_integrity_compare(reference->bdev->bd_disk,
1559 				rdev->bdev->bd_disk) < 0)
1560 			return -EINVAL;
1561 	}
1562 	/*
1563 	 * All component devices are integrity capable and have matching
1564 	 * profiles, register the common profile for the md device.
1565 	 */
1566 	if (blk_integrity_register(mddev->gendisk,
1567 			bdev_get_integrity(reference->bdev)) != 0) {
1568 		printk(KERN_ERR "md: failed to register integrity for %s\n",
1569 			mdname(mddev));
1570 		return -EINVAL;
1571 	}
1572 	printk(KERN_NOTICE "md: data integrity on %s enabled\n",
1573 		mdname(mddev));
1574 	return 0;
1575 }
1576 EXPORT_SYMBOL(md_integrity_register);
1577 
1578 /* Disable data integrity if non-capable/non-matching disk is being added */
1579 void md_integrity_add_rdev(mdk_rdev_t *rdev, mddev_t *mddev)
1580 {
1581 	struct blk_integrity *bi_rdev = bdev_get_integrity(rdev->bdev);
1582 	struct blk_integrity *bi_mddev = blk_get_integrity(mddev->gendisk);
1583 
1584 	if (!bi_mddev) /* nothing to do */
1585 		return;
1586 	if (rdev->raid_disk < 0) /* skip spares */
1587 		return;
1588 	if (bi_rdev && blk_integrity_compare(mddev->gendisk,
1589 					     rdev->bdev->bd_disk) >= 0)
1590 		return;
1591 	printk(KERN_NOTICE "disabling data integrity on %s\n", mdname(mddev));
1592 	blk_integrity_unregister(mddev->gendisk);
1593 }
1594 EXPORT_SYMBOL(md_integrity_add_rdev);
1595 
1596 static int bind_rdev_to_array(mdk_rdev_t * rdev, mddev_t * mddev)
1597 {
1598 	char b[BDEVNAME_SIZE];
1599 	struct kobject *ko;
1600 	char *s;
1601 	int err;
1602 
1603 	if (rdev->mddev) {
1604 		MD_BUG();
1605 		return -EINVAL;
1606 	}
1607 
1608 	/* prevent duplicates */
1609 	if (find_rdev(mddev, rdev->bdev->bd_dev))
1610 		return -EEXIST;
1611 
1612 	/* make sure rdev->sectors exceeds mddev->dev_sectors */
1613 	if (rdev->sectors && (mddev->dev_sectors == 0 ||
1614 			rdev->sectors < mddev->dev_sectors)) {
1615 		if (mddev->pers) {
1616 			/* Cannot change size, so fail
1617 			 * If mddev->level <= 0, then we don't care
1618 			 * about aligning sizes (e.g. linear)
1619 			 */
1620 			if (mddev->level > 0)
1621 				return -ENOSPC;
1622 		} else
1623 			mddev->dev_sectors = rdev->sectors;
1624 	}
1625 
1626 	/* Verify rdev->desc_nr is unique.
1627 	 * If it is -1, assign a free number, else
1628 	 * check number is not in use
1629 	 */
1630 	if (rdev->desc_nr < 0) {
1631 		int choice = 0;
1632 		if (mddev->pers) choice = mddev->raid_disks;
1633 		while (find_rdev_nr(mddev, choice))
1634 			choice++;
1635 		rdev->desc_nr = choice;
1636 	} else {
1637 		if (find_rdev_nr(mddev, rdev->desc_nr))
1638 			return -EBUSY;
1639 	}
1640 	if (mddev->max_disks && rdev->desc_nr >= mddev->max_disks) {
1641 		printk(KERN_WARNING "md: %s: array is limited to %d devices\n",
1642 		       mdname(mddev), mddev->max_disks);
1643 		return -EBUSY;
1644 	}
1645 	bdevname(rdev->bdev,b);
1646 	while ( (s=strchr(b, '/')) != NULL)
1647 		*s = '!';
1648 
1649 	rdev->mddev = mddev;
1650 	printk(KERN_INFO "md: bind<%s>\n", b);
1651 
1652 	if ((err = kobject_add(&rdev->kobj, &mddev->kobj, "dev-%s", b)))
1653 		goto fail;
1654 
1655 	ko = &part_to_dev(rdev->bdev->bd_part)->kobj;
1656 	if ((err = sysfs_create_link(&rdev->kobj, ko, "block"))) {
1657 		kobject_del(&rdev->kobj);
1658 		goto fail;
1659 	}
1660 	rdev->sysfs_state = sysfs_get_dirent(rdev->kobj.sd, "state");
1661 
1662 	list_add_rcu(&rdev->same_set, &mddev->disks);
1663 	bd_claim_by_disk(rdev->bdev, rdev->bdev->bd_holder, mddev->gendisk);
1664 
1665 	/* May as well allow recovery to be retried once */
1666 	mddev->recovery_disabled = 0;
1667 
1668 	return 0;
1669 
1670  fail:
1671 	printk(KERN_WARNING "md: failed to register dev-%s for %s\n",
1672 	       b, mdname(mddev));
1673 	return err;
1674 }
1675 
1676 static void md_delayed_delete(struct work_struct *ws)
1677 {
1678 	mdk_rdev_t *rdev = container_of(ws, mdk_rdev_t, del_work);
1679 	kobject_del(&rdev->kobj);
1680 	kobject_put(&rdev->kobj);
1681 }
1682 
1683 static void unbind_rdev_from_array(mdk_rdev_t * rdev)
1684 {
1685 	char b[BDEVNAME_SIZE];
1686 	if (!rdev->mddev) {
1687 		MD_BUG();
1688 		return;
1689 	}
1690 	bd_release_from_disk(rdev->bdev, rdev->mddev->gendisk);
1691 	list_del_rcu(&rdev->same_set);
1692 	printk(KERN_INFO "md: unbind<%s>\n", bdevname(rdev->bdev,b));
1693 	rdev->mddev = NULL;
1694 	sysfs_remove_link(&rdev->kobj, "block");
1695 	sysfs_put(rdev->sysfs_state);
1696 	rdev->sysfs_state = NULL;
1697 	/* We need to delay this, otherwise we can deadlock when
1698 	 * writing to 'remove' to "dev/state".  We also need
1699 	 * to delay it due to rcu usage.
1700 	 */
1701 	synchronize_rcu();
1702 	INIT_WORK(&rdev->del_work, md_delayed_delete);
1703 	kobject_get(&rdev->kobj);
1704 	schedule_work(&rdev->del_work);
1705 }
1706 
1707 /*
1708  * prevent the device from being mounted, repartitioned or
1709  * otherwise reused by a RAID array (or any other kernel
1710  * subsystem), by bd_claiming the device.
1711  */
1712 static int lock_rdev(mdk_rdev_t *rdev, dev_t dev, int shared)
1713 {
1714 	int err = 0;
1715 	struct block_device *bdev;
1716 	char b[BDEVNAME_SIZE];
1717 
1718 	bdev = open_by_devnum(dev, FMODE_READ|FMODE_WRITE);
1719 	if (IS_ERR(bdev)) {
1720 		printk(KERN_ERR "md: could not open %s.\n",
1721 			__bdevname(dev, b));
1722 		return PTR_ERR(bdev);
1723 	}
1724 	err = bd_claim(bdev, shared ? (mdk_rdev_t *)lock_rdev : rdev);
1725 	if (err) {
1726 		printk(KERN_ERR "md: could not bd_claim %s.\n",
1727 			bdevname(bdev, b));
1728 		blkdev_put(bdev, FMODE_READ|FMODE_WRITE);
1729 		return err;
1730 	}
1731 	if (!shared)
1732 		set_bit(AllReserved, &rdev->flags);
1733 	rdev->bdev = bdev;
1734 	return err;
1735 }
1736 
1737 static void unlock_rdev(mdk_rdev_t *rdev)
1738 {
1739 	struct block_device *bdev = rdev->bdev;
1740 	rdev->bdev = NULL;
1741 	if (!bdev)
1742 		MD_BUG();
1743 	bd_release(bdev);
1744 	blkdev_put(bdev, FMODE_READ|FMODE_WRITE);
1745 }
1746 
1747 void md_autodetect_dev(dev_t dev);
1748 
1749 static void export_rdev(mdk_rdev_t * rdev)
1750 {
1751 	char b[BDEVNAME_SIZE];
1752 	printk(KERN_INFO "md: export_rdev(%s)\n",
1753 		bdevname(rdev->bdev,b));
1754 	if (rdev->mddev)
1755 		MD_BUG();
1756 	free_disk_sb(rdev);
1757 #ifndef MODULE
1758 	if (test_bit(AutoDetected, &rdev->flags))
1759 		md_autodetect_dev(rdev->bdev->bd_dev);
1760 #endif
1761 	unlock_rdev(rdev);
1762 	kobject_put(&rdev->kobj);
1763 }
1764 
1765 static void kick_rdev_from_array(mdk_rdev_t * rdev)
1766 {
1767 	unbind_rdev_from_array(rdev);
1768 	export_rdev(rdev);
1769 }
1770 
1771 static void export_array(mddev_t *mddev)
1772 {
1773 	mdk_rdev_t *rdev, *tmp;
1774 
1775 	rdev_for_each(rdev, tmp, mddev) {
1776 		if (!rdev->mddev) {
1777 			MD_BUG();
1778 			continue;
1779 		}
1780 		kick_rdev_from_array(rdev);
1781 	}
1782 	if (!list_empty(&mddev->disks))
1783 		MD_BUG();
1784 	mddev->raid_disks = 0;
1785 	mddev->major_version = 0;
1786 }
1787 
1788 static void print_desc(mdp_disk_t *desc)
1789 {
1790 	printk(" DISK<N:%d,(%d,%d),R:%d,S:%d>\n", desc->number,
1791 		desc->major,desc->minor,desc->raid_disk,desc->state);
1792 }
1793 
1794 static void print_sb_90(mdp_super_t *sb)
1795 {
1796 	int i;
1797 
1798 	printk(KERN_INFO
1799 		"md:  SB: (V:%d.%d.%d) ID:<%08x.%08x.%08x.%08x> CT:%08x\n",
1800 		sb->major_version, sb->minor_version, sb->patch_version,
1801 		sb->set_uuid0, sb->set_uuid1, sb->set_uuid2, sb->set_uuid3,
1802 		sb->ctime);
1803 	printk(KERN_INFO "md:     L%d S%08d ND:%d RD:%d md%d LO:%d CS:%d\n",
1804 		sb->level, sb->size, sb->nr_disks, sb->raid_disks,
1805 		sb->md_minor, sb->layout, sb->chunk_size);
1806 	printk(KERN_INFO "md:     UT:%08x ST:%d AD:%d WD:%d"
1807 		" FD:%d SD:%d CSUM:%08x E:%08lx\n",
1808 		sb->utime, sb->state, sb->active_disks, sb->working_disks,
1809 		sb->failed_disks, sb->spare_disks,
1810 		sb->sb_csum, (unsigned long)sb->events_lo);
1811 
1812 	printk(KERN_INFO);
1813 	for (i = 0; i < MD_SB_DISKS; i++) {
1814 		mdp_disk_t *desc;
1815 
1816 		desc = sb->disks + i;
1817 		if (desc->number || desc->major || desc->minor ||
1818 		    desc->raid_disk || (desc->state && (desc->state != 4))) {
1819 			printk("     D %2d: ", i);
1820 			print_desc(desc);
1821 		}
1822 	}
1823 	printk(KERN_INFO "md:     THIS: ");
1824 	print_desc(&sb->this_disk);
1825 }
1826 
1827 static void print_sb_1(struct mdp_superblock_1 *sb)
1828 {
1829 	__u8 *uuid;
1830 
1831 	uuid = sb->set_uuid;
1832 	printk(KERN_INFO
1833 	       "md:  SB: (V:%u) (F:0x%08x) Array-ID:<%02x%02x%02x%02x"
1834 	       ":%02x%02x:%02x%02x:%02x%02x:%02x%02x%02x%02x%02x%02x>\n"
1835 	       "md:    Name: \"%s\" CT:%llu\n",
1836 		le32_to_cpu(sb->major_version),
1837 		le32_to_cpu(sb->feature_map),
1838 		uuid[0], uuid[1], uuid[2], uuid[3],
1839 		uuid[4], uuid[5], uuid[6], uuid[7],
1840 		uuid[8], uuid[9], uuid[10], uuid[11],
1841 		uuid[12], uuid[13], uuid[14], uuid[15],
1842 		sb->set_name,
1843 		(unsigned long long)le64_to_cpu(sb->ctime)
1844 		       & MD_SUPERBLOCK_1_TIME_SEC_MASK);
1845 
1846 	uuid = sb->device_uuid;
1847 	printk(KERN_INFO
1848 	       "md:       L%u SZ%llu RD:%u LO:%u CS:%u DO:%llu DS:%llu SO:%llu"
1849 			" RO:%llu\n"
1850 	       "md:     Dev:%08x UUID: %02x%02x%02x%02x:%02x%02x:%02x%02x:%02x%02x"
1851 	                ":%02x%02x%02x%02x%02x%02x\n"
1852 	       "md:       (F:0x%08x) UT:%llu Events:%llu ResyncOffset:%llu CSUM:0x%08x\n"
1853 	       "md:         (MaxDev:%u) \n",
1854 		le32_to_cpu(sb->level),
1855 		(unsigned long long)le64_to_cpu(sb->size),
1856 		le32_to_cpu(sb->raid_disks),
1857 		le32_to_cpu(sb->layout),
1858 		le32_to_cpu(sb->chunksize),
1859 		(unsigned long long)le64_to_cpu(sb->data_offset),
1860 		(unsigned long long)le64_to_cpu(sb->data_size),
1861 		(unsigned long long)le64_to_cpu(sb->super_offset),
1862 		(unsigned long long)le64_to_cpu(sb->recovery_offset),
1863 		le32_to_cpu(sb->dev_number),
1864 		uuid[0], uuid[1], uuid[2], uuid[3],
1865 		uuid[4], uuid[5], uuid[6], uuid[7],
1866 		uuid[8], uuid[9], uuid[10], uuid[11],
1867 		uuid[12], uuid[13], uuid[14], uuid[15],
1868 		sb->devflags,
1869 		(unsigned long long)le64_to_cpu(sb->utime) & MD_SUPERBLOCK_1_TIME_SEC_MASK,
1870 		(unsigned long long)le64_to_cpu(sb->events),
1871 		(unsigned long long)le64_to_cpu(sb->resync_offset),
1872 		le32_to_cpu(sb->sb_csum),
1873 		le32_to_cpu(sb->max_dev)
1874 		);
1875 }
1876 
1877 static void print_rdev(mdk_rdev_t *rdev, int major_version)
1878 {
1879 	char b[BDEVNAME_SIZE];
1880 	printk(KERN_INFO "md: rdev %s, Sect:%08llu F:%d S:%d DN:%u\n",
1881 		bdevname(rdev->bdev, b), (unsigned long long)rdev->sectors,
1882 	        test_bit(Faulty, &rdev->flags), test_bit(In_sync, &rdev->flags),
1883 	        rdev->desc_nr);
1884 	if (rdev->sb_loaded) {
1885 		printk(KERN_INFO "md: rdev superblock (MJ:%d):\n", major_version);
1886 		switch (major_version) {
1887 		case 0:
1888 			print_sb_90((mdp_super_t*)page_address(rdev->sb_page));
1889 			break;
1890 		case 1:
1891 			print_sb_1((struct mdp_superblock_1 *)page_address(rdev->sb_page));
1892 			break;
1893 		}
1894 	} else
1895 		printk(KERN_INFO "md: no rdev superblock!\n");
1896 }
1897 
1898 static void md_print_devices(void)
1899 {
1900 	struct list_head *tmp;
1901 	mdk_rdev_t *rdev;
1902 	mddev_t *mddev;
1903 	char b[BDEVNAME_SIZE];
1904 
1905 	printk("\n");
1906 	printk("md:	**********************************\n");
1907 	printk("md:	* <COMPLETE RAID STATE PRINTOUT> *\n");
1908 	printk("md:	**********************************\n");
1909 	for_each_mddev(mddev, tmp) {
1910 
1911 		if (mddev->bitmap)
1912 			bitmap_print_sb(mddev->bitmap);
1913 		else
1914 			printk("%s: ", mdname(mddev));
1915 		list_for_each_entry(rdev, &mddev->disks, same_set)
1916 			printk("<%s>", bdevname(rdev->bdev,b));
1917 		printk("\n");
1918 
1919 		list_for_each_entry(rdev, &mddev->disks, same_set)
1920 			print_rdev(rdev, mddev->major_version);
1921 	}
1922 	printk("md:	**********************************\n");
1923 	printk("\n");
1924 }
1925 
1926 
1927 static void sync_sbs(mddev_t * mddev, int nospares)
1928 {
1929 	/* Update each superblock (in-memory image), but
1930 	 * if we are allowed to, skip spares which already
1931 	 * have the right event counter, or have one earlier
1932 	 * (which would mean they aren't being marked as dirty
1933 	 * with the rest of the array)
1934 	 */
1935 	mdk_rdev_t *rdev;
1936 
1937 	/* First make sure individual recovery_offsets are correct */
1938 	list_for_each_entry(rdev, &mddev->disks, same_set) {
1939 		if (rdev->raid_disk >= 0 &&
1940 		    !test_bit(In_sync, &rdev->flags) &&
1941 		    mddev->curr_resync_completed > rdev->recovery_offset)
1942 				rdev->recovery_offset = mddev->curr_resync_completed;
1943 
1944 	}
1945 	list_for_each_entry(rdev, &mddev->disks, same_set) {
1946 		if (rdev->sb_events == mddev->events ||
1947 		    (nospares &&
1948 		     rdev->raid_disk < 0 &&
1949 		     (rdev->sb_events&1)==0 &&
1950 		     rdev->sb_events+1 == mddev->events)) {
1951 			/* Don't update this superblock */
1952 			rdev->sb_loaded = 2;
1953 		} else {
1954 			super_types[mddev->major_version].
1955 				sync_super(mddev, rdev);
1956 			rdev->sb_loaded = 1;
1957 		}
1958 	}
1959 }
1960 
1961 static void md_update_sb(mddev_t * mddev, int force_change)
1962 {
1963 	mdk_rdev_t *rdev;
1964 	int sync_req;
1965 	int nospares = 0;
1966 
1967 	mddev->utime = get_seconds();
1968 	if (mddev->external)
1969 		return;
1970 repeat:
1971 	spin_lock_irq(&mddev->write_lock);
1972 
1973 	set_bit(MD_CHANGE_PENDING, &mddev->flags);
1974 	if (test_and_clear_bit(MD_CHANGE_DEVS, &mddev->flags))
1975 		force_change = 1;
1976 	if (test_and_clear_bit(MD_CHANGE_CLEAN, &mddev->flags))
1977 		/* just a clean<-> dirty transition, possibly leave spares alone,
1978 		 * though if events isn't the right even/odd, we will have to do
1979 		 * spares after all
1980 		 */
1981 		nospares = 1;
1982 	if (force_change)
1983 		nospares = 0;
1984 	if (mddev->degraded)
1985 		/* If the array is degraded, then skipping spares is both
1986 		 * dangerous and fairly pointless.
1987 		 * Dangerous because a device that was removed from the array
1988 		 * might have a event_count that still looks up-to-date,
1989 		 * so it can be re-added without a resync.
1990 		 * Pointless because if there are any spares to skip,
1991 		 * then a recovery will happen and soon that array won't
1992 		 * be degraded any more and the spare can go back to sleep then.
1993 		 */
1994 		nospares = 0;
1995 
1996 	sync_req = mddev->in_sync;
1997 
1998 	/* If this is just a dirty<->clean transition, and the array is clean
1999 	 * and 'events' is odd, we can roll back to the previous clean state */
2000 	if (nospares
2001 	    && (mddev->in_sync && mddev->recovery_cp == MaxSector)
2002 	    && (mddev->events & 1)
2003 	    && mddev->events != 1)
2004 		mddev->events--;
2005 	else {
2006 		/* otherwise we have to go forward and ... */
2007 		mddev->events ++;
2008 		if (!mddev->in_sync || mddev->recovery_cp != MaxSector) { /* not clean */
2009 			/* .. if the array isn't clean, an 'even' event must also go
2010 			 * to spares. */
2011 			if ((mddev->events&1)==0)
2012 				nospares = 0;
2013 		} else {
2014 			/* otherwise an 'odd' event must go to spares */
2015 			if ((mddev->events&1))
2016 				nospares = 0;
2017 		}
2018 	}
2019 
2020 	if (!mddev->events) {
2021 		/*
2022 		 * oops, this 64-bit counter should never wrap.
2023 		 * Either we are in around ~1 trillion A.C., assuming
2024 		 * 1 reboot per second, or we have a bug:
2025 		 */
2026 		MD_BUG();
2027 		mddev->events --;
2028 	}
2029 
2030 	/*
2031 	 * do not write anything to disk if using
2032 	 * nonpersistent superblocks
2033 	 */
2034 	if (!mddev->persistent) {
2035 		if (!mddev->external)
2036 			clear_bit(MD_CHANGE_PENDING, &mddev->flags);
2037 
2038 		spin_unlock_irq(&mddev->write_lock);
2039 		wake_up(&mddev->sb_wait);
2040 		return;
2041 	}
2042 	sync_sbs(mddev, nospares);
2043 	spin_unlock_irq(&mddev->write_lock);
2044 
2045 	dprintk(KERN_INFO
2046 		"md: updating %s RAID superblock on device (in sync %d)\n",
2047 		mdname(mddev),mddev->in_sync);
2048 
2049 	bitmap_update_sb(mddev->bitmap);
2050 	list_for_each_entry(rdev, &mddev->disks, same_set) {
2051 		char b[BDEVNAME_SIZE];
2052 		dprintk(KERN_INFO "md: ");
2053 		if (rdev->sb_loaded != 1)
2054 			continue; /* no noise on spare devices */
2055 		if (test_bit(Faulty, &rdev->flags))
2056 			dprintk("(skipping faulty ");
2057 
2058 		dprintk("%s ", bdevname(rdev->bdev,b));
2059 		if (!test_bit(Faulty, &rdev->flags)) {
2060 			md_super_write(mddev,rdev,
2061 				       rdev->sb_start, rdev->sb_size,
2062 				       rdev->sb_page);
2063 			dprintk(KERN_INFO "(write) %s's sb offset: %llu\n",
2064 				bdevname(rdev->bdev,b),
2065 				(unsigned long long)rdev->sb_start);
2066 			rdev->sb_events = mddev->events;
2067 
2068 		} else
2069 			dprintk(")\n");
2070 		if (mddev->level == LEVEL_MULTIPATH)
2071 			/* only need to write one superblock... */
2072 			break;
2073 	}
2074 	md_super_wait(mddev);
2075 	/* if there was a failure, MD_CHANGE_DEVS was set, and we re-write super */
2076 
2077 	spin_lock_irq(&mddev->write_lock);
2078 	if (mddev->in_sync != sync_req ||
2079 	    test_bit(MD_CHANGE_DEVS, &mddev->flags)) {
2080 		/* have to write it out again */
2081 		spin_unlock_irq(&mddev->write_lock);
2082 		goto repeat;
2083 	}
2084 	clear_bit(MD_CHANGE_PENDING, &mddev->flags);
2085 	spin_unlock_irq(&mddev->write_lock);
2086 	wake_up(&mddev->sb_wait);
2087 	if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
2088 		sysfs_notify(&mddev->kobj, NULL, "sync_completed");
2089 
2090 }
2091 
2092 /* words written to sysfs files may, or may not, be \n terminated.
2093  * We want to accept with case. For this we use cmd_match.
2094  */
2095 static int cmd_match(const char *cmd, const char *str)
2096 {
2097 	/* See if cmd, written into a sysfs file, matches
2098 	 * str.  They must either be the same, or cmd can
2099 	 * have a trailing newline
2100 	 */
2101 	while (*cmd && *str && *cmd == *str) {
2102 		cmd++;
2103 		str++;
2104 	}
2105 	if (*cmd == '\n')
2106 		cmd++;
2107 	if (*str || *cmd)
2108 		return 0;
2109 	return 1;
2110 }
2111 
2112 struct rdev_sysfs_entry {
2113 	struct attribute attr;
2114 	ssize_t (*show)(mdk_rdev_t *, char *);
2115 	ssize_t (*store)(mdk_rdev_t *, const char *, size_t);
2116 };
2117 
2118 static ssize_t
2119 state_show(mdk_rdev_t *rdev, char *page)
2120 {
2121 	char *sep = "";
2122 	size_t len = 0;
2123 
2124 	if (test_bit(Faulty, &rdev->flags)) {
2125 		len+= sprintf(page+len, "%sfaulty",sep);
2126 		sep = ",";
2127 	}
2128 	if (test_bit(In_sync, &rdev->flags)) {
2129 		len += sprintf(page+len, "%sin_sync",sep);
2130 		sep = ",";
2131 	}
2132 	if (test_bit(WriteMostly, &rdev->flags)) {
2133 		len += sprintf(page+len, "%swrite_mostly",sep);
2134 		sep = ",";
2135 	}
2136 	if (test_bit(Blocked, &rdev->flags)) {
2137 		len += sprintf(page+len, "%sblocked", sep);
2138 		sep = ",";
2139 	}
2140 	if (!test_bit(Faulty, &rdev->flags) &&
2141 	    !test_bit(In_sync, &rdev->flags)) {
2142 		len += sprintf(page+len, "%sspare", sep);
2143 		sep = ",";
2144 	}
2145 	return len+sprintf(page+len, "\n");
2146 }
2147 
2148 static ssize_t
2149 state_store(mdk_rdev_t *rdev, const char *buf, size_t len)
2150 {
2151 	/* can write
2152 	 *  faulty  - simulates and error
2153 	 *  remove  - disconnects the device
2154 	 *  writemostly - sets write_mostly
2155 	 *  -writemostly - clears write_mostly
2156 	 *  blocked - sets the Blocked flag
2157 	 *  -blocked - clears the Blocked flag
2158 	 *  insync - sets Insync providing device isn't active
2159 	 */
2160 	int err = -EINVAL;
2161 	if (cmd_match(buf, "faulty") && rdev->mddev->pers) {
2162 		md_error(rdev->mddev, rdev);
2163 		err = 0;
2164 	} else if (cmd_match(buf, "remove")) {
2165 		if (rdev->raid_disk >= 0)
2166 			err = -EBUSY;
2167 		else {
2168 			mddev_t *mddev = rdev->mddev;
2169 			kick_rdev_from_array(rdev);
2170 			if (mddev->pers)
2171 				md_update_sb(mddev, 1);
2172 			md_new_event(mddev);
2173 			err = 0;
2174 		}
2175 	} else if (cmd_match(buf, "writemostly")) {
2176 		set_bit(WriteMostly, &rdev->flags);
2177 		err = 0;
2178 	} else if (cmd_match(buf, "-writemostly")) {
2179 		clear_bit(WriteMostly, &rdev->flags);
2180 		err = 0;
2181 	} else if (cmd_match(buf, "blocked")) {
2182 		set_bit(Blocked, &rdev->flags);
2183 		err = 0;
2184 	} else if (cmd_match(buf, "-blocked")) {
2185 		clear_bit(Blocked, &rdev->flags);
2186 		wake_up(&rdev->blocked_wait);
2187 		set_bit(MD_RECOVERY_NEEDED, &rdev->mddev->recovery);
2188 		md_wakeup_thread(rdev->mddev->thread);
2189 
2190 		err = 0;
2191 	} else if (cmd_match(buf, "insync") && rdev->raid_disk == -1) {
2192 		set_bit(In_sync, &rdev->flags);
2193 		err = 0;
2194 	}
2195 	if (!err && rdev->sysfs_state)
2196 		sysfs_notify_dirent(rdev->sysfs_state);
2197 	return err ? err : len;
2198 }
2199 static struct rdev_sysfs_entry rdev_state =
2200 __ATTR(state, S_IRUGO|S_IWUSR, state_show, state_store);
2201 
2202 static ssize_t
2203 errors_show(mdk_rdev_t *rdev, char *page)
2204 {
2205 	return sprintf(page, "%d\n", atomic_read(&rdev->corrected_errors));
2206 }
2207 
2208 static ssize_t
2209 errors_store(mdk_rdev_t *rdev, const char *buf, size_t len)
2210 {
2211 	char *e;
2212 	unsigned long n = simple_strtoul(buf, &e, 10);
2213 	if (*buf && (*e == 0 || *e == '\n')) {
2214 		atomic_set(&rdev->corrected_errors, n);
2215 		return len;
2216 	}
2217 	return -EINVAL;
2218 }
2219 static struct rdev_sysfs_entry rdev_errors =
2220 __ATTR(errors, S_IRUGO|S_IWUSR, errors_show, errors_store);
2221 
2222 static ssize_t
2223 slot_show(mdk_rdev_t *rdev, char *page)
2224 {
2225 	if (rdev->raid_disk < 0)
2226 		return sprintf(page, "none\n");
2227 	else
2228 		return sprintf(page, "%d\n", rdev->raid_disk);
2229 }
2230 
2231 static ssize_t
2232 slot_store(mdk_rdev_t *rdev, const char *buf, size_t len)
2233 {
2234 	char *e;
2235 	int err;
2236 	char nm[20];
2237 	int slot = simple_strtoul(buf, &e, 10);
2238 	if (strncmp(buf, "none", 4)==0)
2239 		slot = -1;
2240 	else if (e==buf || (*e && *e!= '\n'))
2241 		return -EINVAL;
2242 	if (rdev->mddev->pers && slot == -1) {
2243 		/* Setting 'slot' on an active array requires also
2244 		 * updating the 'rd%d' link, and communicating
2245 		 * with the personality with ->hot_*_disk.
2246 		 * For now we only support removing
2247 		 * failed/spare devices.  This normally happens automatically,
2248 		 * but not when the metadata is externally managed.
2249 		 */
2250 		if (rdev->raid_disk == -1)
2251 			return -EEXIST;
2252 		/* personality does all needed checks */
2253 		if (rdev->mddev->pers->hot_add_disk == NULL)
2254 			return -EINVAL;
2255 		err = rdev->mddev->pers->
2256 			hot_remove_disk(rdev->mddev, rdev->raid_disk);
2257 		if (err)
2258 			return err;
2259 		sprintf(nm, "rd%d", rdev->raid_disk);
2260 		sysfs_remove_link(&rdev->mddev->kobj, nm);
2261 		set_bit(MD_RECOVERY_NEEDED, &rdev->mddev->recovery);
2262 		md_wakeup_thread(rdev->mddev->thread);
2263 	} else if (rdev->mddev->pers) {
2264 		mdk_rdev_t *rdev2;
2265 		/* Activating a spare .. or possibly reactivating
2266 		 * if we ever get bitmaps working here.
2267 		 */
2268 
2269 		if (rdev->raid_disk != -1)
2270 			return -EBUSY;
2271 
2272 		if (rdev->mddev->pers->hot_add_disk == NULL)
2273 			return -EINVAL;
2274 
2275 		list_for_each_entry(rdev2, &rdev->mddev->disks, same_set)
2276 			if (rdev2->raid_disk == slot)
2277 				return -EEXIST;
2278 
2279 		rdev->raid_disk = slot;
2280 		if (test_bit(In_sync, &rdev->flags))
2281 			rdev->saved_raid_disk = slot;
2282 		else
2283 			rdev->saved_raid_disk = -1;
2284 		err = rdev->mddev->pers->
2285 			hot_add_disk(rdev->mddev, rdev);
2286 		if (err) {
2287 			rdev->raid_disk = -1;
2288 			return err;
2289 		} else
2290 			sysfs_notify_dirent(rdev->sysfs_state);
2291 		sprintf(nm, "rd%d", rdev->raid_disk);
2292 		if (sysfs_create_link(&rdev->mddev->kobj, &rdev->kobj, nm))
2293 			printk(KERN_WARNING
2294 			       "md: cannot register "
2295 			       "%s for %s\n",
2296 			       nm, mdname(rdev->mddev));
2297 
2298 		/* don't wakeup anyone, leave that to userspace. */
2299 	} else {
2300 		if (slot >= rdev->mddev->raid_disks)
2301 			return -ENOSPC;
2302 		rdev->raid_disk = slot;
2303 		/* assume it is working */
2304 		clear_bit(Faulty, &rdev->flags);
2305 		clear_bit(WriteMostly, &rdev->flags);
2306 		set_bit(In_sync, &rdev->flags);
2307 		sysfs_notify_dirent(rdev->sysfs_state);
2308 	}
2309 	return len;
2310 }
2311 
2312 
2313 static struct rdev_sysfs_entry rdev_slot =
2314 __ATTR(slot, S_IRUGO|S_IWUSR, slot_show, slot_store);
2315 
2316 static ssize_t
2317 offset_show(mdk_rdev_t *rdev, char *page)
2318 {
2319 	return sprintf(page, "%llu\n", (unsigned long long)rdev->data_offset);
2320 }
2321 
2322 static ssize_t
2323 offset_store(mdk_rdev_t *rdev, const char *buf, size_t len)
2324 {
2325 	char *e;
2326 	unsigned long long offset = simple_strtoull(buf, &e, 10);
2327 	if (e==buf || (*e && *e != '\n'))
2328 		return -EINVAL;
2329 	if (rdev->mddev->pers && rdev->raid_disk >= 0)
2330 		return -EBUSY;
2331 	if (rdev->sectors && rdev->mddev->external)
2332 		/* Must set offset before size, so overlap checks
2333 		 * can be sane */
2334 		return -EBUSY;
2335 	rdev->data_offset = offset;
2336 	return len;
2337 }
2338 
2339 static struct rdev_sysfs_entry rdev_offset =
2340 __ATTR(offset, S_IRUGO|S_IWUSR, offset_show, offset_store);
2341 
2342 static ssize_t
2343 rdev_size_show(mdk_rdev_t *rdev, char *page)
2344 {
2345 	return sprintf(page, "%llu\n", (unsigned long long)rdev->sectors / 2);
2346 }
2347 
2348 static int overlaps(sector_t s1, sector_t l1, sector_t s2, sector_t l2)
2349 {
2350 	/* check if two start/length pairs overlap */
2351 	if (s1+l1 <= s2)
2352 		return 0;
2353 	if (s2+l2 <= s1)
2354 		return 0;
2355 	return 1;
2356 }
2357 
2358 static int strict_blocks_to_sectors(const char *buf, sector_t *sectors)
2359 {
2360 	unsigned long long blocks;
2361 	sector_t new;
2362 
2363 	if (strict_strtoull(buf, 10, &blocks) < 0)
2364 		return -EINVAL;
2365 
2366 	if (blocks & 1ULL << (8 * sizeof(blocks) - 1))
2367 		return -EINVAL; /* sector conversion overflow */
2368 
2369 	new = blocks * 2;
2370 	if (new != blocks * 2)
2371 		return -EINVAL; /* unsigned long long to sector_t overflow */
2372 
2373 	*sectors = new;
2374 	return 0;
2375 }
2376 
2377 static ssize_t
2378 rdev_size_store(mdk_rdev_t *rdev, const char *buf, size_t len)
2379 {
2380 	mddev_t *my_mddev = rdev->mddev;
2381 	sector_t oldsectors = rdev->sectors;
2382 	sector_t sectors;
2383 
2384 	if (strict_blocks_to_sectors(buf, &sectors) < 0)
2385 		return -EINVAL;
2386 	if (my_mddev->pers && rdev->raid_disk >= 0) {
2387 		if (my_mddev->persistent) {
2388 			sectors = super_types[my_mddev->major_version].
2389 				rdev_size_change(rdev, sectors);
2390 			if (!sectors)
2391 				return -EBUSY;
2392 		} else if (!sectors)
2393 			sectors = (rdev->bdev->bd_inode->i_size >> 9) -
2394 				rdev->data_offset;
2395 	}
2396 	if (sectors < my_mddev->dev_sectors)
2397 		return -EINVAL; /* component must fit device */
2398 
2399 	rdev->sectors = sectors;
2400 	if (sectors > oldsectors && my_mddev->external) {
2401 		/* need to check that all other rdevs with the same ->bdev
2402 		 * do not overlap.  We need to unlock the mddev to avoid
2403 		 * a deadlock.  We have already changed rdev->sectors, and if
2404 		 * we have to change it back, we will have the lock again.
2405 		 */
2406 		mddev_t *mddev;
2407 		int overlap = 0;
2408 		struct list_head *tmp;
2409 
2410 		mddev_unlock(my_mddev);
2411 		for_each_mddev(mddev, tmp) {
2412 			mdk_rdev_t *rdev2;
2413 
2414 			mddev_lock(mddev);
2415 			list_for_each_entry(rdev2, &mddev->disks, same_set)
2416 				if (test_bit(AllReserved, &rdev2->flags) ||
2417 				    (rdev->bdev == rdev2->bdev &&
2418 				     rdev != rdev2 &&
2419 				     overlaps(rdev->data_offset, rdev->sectors,
2420 					      rdev2->data_offset,
2421 					      rdev2->sectors))) {
2422 					overlap = 1;
2423 					break;
2424 				}
2425 			mddev_unlock(mddev);
2426 			if (overlap) {
2427 				mddev_put(mddev);
2428 				break;
2429 			}
2430 		}
2431 		mddev_lock(my_mddev);
2432 		if (overlap) {
2433 			/* Someone else could have slipped in a size
2434 			 * change here, but doing so is just silly.
2435 			 * We put oldsectors back because we *know* it is
2436 			 * safe, and trust userspace not to race with
2437 			 * itself
2438 			 */
2439 			rdev->sectors = oldsectors;
2440 			return -EBUSY;
2441 		}
2442 	}
2443 	return len;
2444 }
2445 
2446 static struct rdev_sysfs_entry rdev_size =
2447 __ATTR(size, S_IRUGO|S_IWUSR, rdev_size_show, rdev_size_store);
2448 
2449 static struct attribute *rdev_default_attrs[] = {
2450 	&rdev_state.attr,
2451 	&rdev_errors.attr,
2452 	&rdev_slot.attr,
2453 	&rdev_offset.attr,
2454 	&rdev_size.attr,
2455 	NULL,
2456 };
2457 static ssize_t
2458 rdev_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
2459 {
2460 	struct rdev_sysfs_entry *entry = container_of(attr, struct rdev_sysfs_entry, attr);
2461 	mdk_rdev_t *rdev = container_of(kobj, mdk_rdev_t, kobj);
2462 	mddev_t *mddev = rdev->mddev;
2463 	ssize_t rv;
2464 
2465 	if (!entry->show)
2466 		return -EIO;
2467 
2468 	rv = mddev ? mddev_lock(mddev) : -EBUSY;
2469 	if (!rv) {
2470 		if (rdev->mddev == NULL)
2471 			rv = -EBUSY;
2472 		else
2473 			rv = entry->show(rdev, page);
2474 		mddev_unlock(mddev);
2475 	}
2476 	return rv;
2477 }
2478 
2479 static ssize_t
2480 rdev_attr_store(struct kobject *kobj, struct attribute *attr,
2481 	      const char *page, size_t length)
2482 {
2483 	struct rdev_sysfs_entry *entry = container_of(attr, struct rdev_sysfs_entry, attr);
2484 	mdk_rdev_t *rdev = container_of(kobj, mdk_rdev_t, kobj);
2485 	ssize_t rv;
2486 	mddev_t *mddev = rdev->mddev;
2487 
2488 	if (!entry->store)
2489 		return -EIO;
2490 	if (!capable(CAP_SYS_ADMIN))
2491 		return -EACCES;
2492 	rv = mddev ? mddev_lock(mddev): -EBUSY;
2493 	if (!rv) {
2494 		if (rdev->mddev == NULL)
2495 			rv = -EBUSY;
2496 		else
2497 			rv = entry->store(rdev, page, length);
2498 		mddev_unlock(mddev);
2499 	}
2500 	return rv;
2501 }
2502 
2503 static void rdev_free(struct kobject *ko)
2504 {
2505 	mdk_rdev_t *rdev = container_of(ko, mdk_rdev_t, kobj);
2506 	kfree(rdev);
2507 }
2508 static struct sysfs_ops rdev_sysfs_ops = {
2509 	.show		= rdev_attr_show,
2510 	.store		= rdev_attr_store,
2511 };
2512 static struct kobj_type rdev_ktype = {
2513 	.release	= rdev_free,
2514 	.sysfs_ops	= &rdev_sysfs_ops,
2515 	.default_attrs	= rdev_default_attrs,
2516 };
2517 
2518 /*
2519  * Import a device. If 'super_format' >= 0, then sanity check the superblock
2520  *
2521  * mark the device faulty if:
2522  *
2523  *   - the device is nonexistent (zero size)
2524  *   - the device has no valid superblock
2525  *
2526  * a faulty rdev _never_ has rdev->sb set.
2527  */
2528 static mdk_rdev_t *md_import_device(dev_t newdev, int super_format, int super_minor)
2529 {
2530 	char b[BDEVNAME_SIZE];
2531 	int err;
2532 	mdk_rdev_t *rdev;
2533 	sector_t size;
2534 
2535 	rdev = kzalloc(sizeof(*rdev), GFP_KERNEL);
2536 	if (!rdev) {
2537 		printk(KERN_ERR "md: could not alloc mem for new device!\n");
2538 		return ERR_PTR(-ENOMEM);
2539 	}
2540 
2541 	if ((err = alloc_disk_sb(rdev)))
2542 		goto abort_free;
2543 
2544 	err = lock_rdev(rdev, newdev, super_format == -2);
2545 	if (err)
2546 		goto abort_free;
2547 
2548 	kobject_init(&rdev->kobj, &rdev_ktype);
2549 
2550 	rdev->desc_nr = -1;
2551 	rdev->saved_raid_disk = -1;
2552 	rdev->raid_disk = -1;
2553 	rdev->flags = 0;
2554 	rdev->data_offset = 0;
2555 	rdev->sb_events = 0;
2556 	atomic_set(&rdev->nr_pending, 0);
2557 	atomic_set(&rdev->read_errors, 0);
2558 	atomic_set(&rdev->corrected_errors, 0);
2559 
2560 	size = rdev->bdev->bd_inode->i_size >> BLOCK_SIZE_BITS;
2561 	if (!size) {
2562 		printk(KERN_WARNING
2563 			"md: %s has zero or unknown size, marking faulty!\n",
2564 			bdevname(rdev->bdev,b));
2565 		err = -EINVAL;
2566 		goto abort_free;
2567 	}
2568 
2569 	if (super_format >= 0) {
2570 		err = super_types[super_format].
2571 			load_super(rdev, NULL, super_minor);
2572 		if (err == -EINVAL) {
2573 			printk(KERN_WARNING
2574 				"md: %s does not have a valid v%d.%d "
2575 			       "superblock, not importing!\n",
2576 				bdevname(rdev->bdev,b),
2577 			       super_format, super_minor);
2578 			goto abort_free;
2579 		}
2580 		if (err < 0) {
2581 			printk(KERN_WARNING
2582 				"md: could not read %s's sb, not importing!\n",
2583 				bdevname(rdev->bdev,b));
2584 			goto abort_free;
2585 		}
2586 	}
2587 
2588 	INIT_LIST_HEAD(&rdev->same_set);
2589 	init_waitqueue_head(&rdev->blocked_wait);
2590 
2591 	return rdev;
2592 
2593 abort_free:
2594 	if (rdev->sb_page) {
2595 		if (rdev->bdev)
2596 			unlock_rdev(rdev);
2597 		free_disk_sb(rdev);
2598 	}
2599 	kfree(rdev);
2600 	return ERR_PTR(err);
2601 }
2602 
2603 /*
2604  * Check a full RAID array for plausibility
2605  */
2606 
2607 
2608 static void analyze_sbs(mddev_t * mddev)
2609 {
2610 	int i;
2611 	mdk_rdev_t *rdev, *freshest, *tmp;
2612 	char b[BDEVNAME_SIZE];
2613 
2614 	freshest = NULL;
2615 	rdev_for_each(rdev, tmp, mddev)
2616 		switch (super_types[mddev->major_version].
2617 			load_super(rdev, freshest, mddev->minor_version)) {
2618 		case 1:
2619 			freshest = rdev;
2620 			break;
2621 		case 0:
2622 			break;
2623 		default:
2624 			printk( KERN_ERR \
2625 				"md: fatal superblock inconsistency in %s"
2626 				" -- removing from array\n",
2627 				bdevname(rdev->bdev,b));
2628 			kick_rdev_from_array(rdev);
2629 		}
2630 
2631 
2632 	super_types[mddev->major_version].
2633 		validate_super(mddev, freshest);
2634 
2635 	i = 0;
2636 	rdev_for_each(rdev, tmp, mddev) {
2637 		if (rdev->desc_nr >= mddev->max_disks ||
2638 		    i > mddev->max_disks) {
2639 			printk(KERN_WARNING
2640 			       "md: %s: %s: only %d devices permitted\n",
2641 			       mdname(mddev), bdevname(rdev->bdev, b),
2642 			       mddev->max_disks);
2643 			kick_rdev_from_array(rdev);
2644 			continue;
2645 		}
2646 		if (rdev != freshest)
2647 			if (super_types[mddev->major_version].
2648 			    validate_super(mddev, rdev)) {
2649 				printk(KERN_WARNING "md: kicking non-fresh %s"
2650 					" from array!\n",
2651 					bdevname(rdev->bdev,b));
2652 				kick_rdev_from_array(rdev);
2653 				continue;
2654 			}
2655 		if (mddev->level == LEVEL_MULTIPATH) {
2656 			rdev->desc_nr = i++;
2657 			rdev->raid_disk = rdev->desc_nr;
2658 			set_bit(In_sync, &rdev->flags);
2659 		} else if (rdev->raid_disk >= (mddev->raid_disks - min(0, mddev->delta_disks))) {
2660 			rdev->raid_disk = -1;
2661 			clear_bit(In_sync, &rdev->flags);
2662 		}
2663 	}
2664 }
2665 
2666 static void md_safemode_timeout(unsigned long data);
2667 
2668 static ssize_t
2669 safe_delay_show(mddev_t *mddev, char *page)
2670 {
2671 	int msec = (mddev->safemode_delay*1000)/HZ;
2672 	return sprintf(page, "%d.%03d\n", msec/1000, msec%1000);
2673 }
2674 static ssize_t
2675 safe_delay_store(mddev_t *mddev, const char *cbuf, size_t len)
2676 {
2677 	int scale=1;
2678 	int dot=0;
2679 	int i;
2680 	unsigned long msec;
2681 	char buf[30];
2682 
2683 	/* remove a period, and count digits after it */
2684 	if (len >= sizeof(buf))
2685 		return -EINVAL;
2686 	strlcpy(buf, cbuf, sizeof(buf));
2687 	for (i=0; i<len; i++) {
2688 		if (dot) {
2689 			if (isdigit(buf[i])) {
2690 				buf[i-1] = buf[i];
2691 				scale *= 10;
2692 			}
2693 			buf[i] = 0;
2694 		} else if (buf[i] == '.') {
2695 			dot=1;
2696 			buf[i] = 0;
2697 		}
2698 	}
2699 	if (strict_strtoul(buf, 10, &msec) < 0)
2700 		return -EINVAL;
2701 	msec = (msec * 1000) / scale;
2702 	if (msec == 0)
2703 		mddev->safemode_delay = 0;
2704 	else {
2705 		unsigned long old_delay = mddev->safemode_delay;
2706 		mddev->safemode_delay = (msec*HZ)/1000;
2707 		if (mddev->safemode_delay == 0)
2708 			mddev->safemode_delay = 1;
2709 		if (mddev->safemode_delay < old_delay)
2710 			md_safemode_timeout((unsigned long)mddev);
2711 	}
2712 	return len;
2713 }
2714 static struct md_sysfs_entry md_safe_delay =
2715 __ATTR(safe_mode_delay, S_IRUGO|S_IWUSR,safe_delay_show, safe_delay_store);
2716 
2717 static ssize_t
2718 level_show(mddev_t *mddev, char *page)
2719 {
2720 	struct mdk_personality *p = mddev->pers;
2721 	if (p)
2722 		return sprintf(page, "%s\n", p->name);
2723 	else if (mddev->clevel[0])
2724 		return sprintf(page, "%s\n", mddev->clevel);
2725 	else if (mddev->level != LEVEL_NONE)
2726 		return sprintf(page, "%d\n", mddev->level);
2727 	else
2728 		return 0;
2729 }
2730 
2731 static ssize_t
2732 level_store(mddev_t *mddev, const char *buf, size_t len)
2733 {
2734 	char level[16];
2735 	ssize_t rv = len;
2736 	struct mdk_personality *pers;
2737 	void *priv;
2738 	mdk_rdev_t *rdev;
2739 
2740 	if (mddev->pers == NULL) {
2741 		if (len == 0)
2742 			return 0;
2743 		if (len >= sizeof(mddev->clevel))
2744 			return -ENOSPC;
2745 		strncpy(mddev->clevel, buf, len);
2746 		if (mddev->clevel[len-1] == '\n')
2747 			len--;
2748 		mddev->clevel[len] = 0;
2749 		mddev->level = LEVEL_NONE;
2750 		return rv;
2751 	}
2752 
2753 	/* request to change the personality.  Need to ensure:
2754 	 *  - array is not engaged in resync/recovery/reshape
2755 	 *  - old personality can be suspended
2756 	 *  - new personality will access other array.
2757 	 */
2758 
2759 	if (mddev->sync_thread || mddev->reshape_position != MaxSector)
2760 		return -EBUSY;
2761 
2762 	if (!mddev->pers->quiesce) {
2763 		printk(KERN_WARNING "md: %s: %s does not support online personality change\n",
2764 		       mdname(mddev), mddev->pers->name);
2765 		return -EINVAL;
2766 	}
2767 
2768 	/* Now find the new personality */
2769 	if (len == 0 || len >= sizeof(level))
2770 		return -EINVAL;
2771 	strncpy(level, buf, len);
2772 	if (level[len-1] == '\n')
2773 		len--;
2774 	level[len] = 0;
2775 
2776 	request_module("md-%s", level);
2777 	spin_lock(&pers_lock);
2778 	pers = find_pers(LEVEL_NONE, level);
2779 	if (!pers || !try_module_get(pers->owner)) {
2780 		spin_unlock(&pers_lock);
2781 		printk(KERN_WARNING "md: personality %s not loaded\n", level);
2782 		return -EINVAL;
2783 	}
2784 	spin_unlock(&pers_lock);
2785 
2786 	if (pers == mddev->pers) {
2787 		/* Nothing to do! */
2788 		module_put(pers->owner);
2789 		return rv;
2790 	}
2791 	if (!pers->takeover) {
2792 		module_put(pers->owner);
2793 		printk(KERN_WARNING "md: %s: %s does not support personality takeover\n",
2794 		       mdname(mddev), level);
2795 		return -EINVAL;
2796 	}
2797 
2798 	/* ->takeover must set new_* and/or delta_disks
2799 	 * if it succeeds, and may set them when it fails.
2800 	 */
2801 	priv = pers->takeover(mddev);
2802 	if (IS_ERR(priv)) {
2803 		mddev->new_level = mddev->level;
2804 		mddev->new_layout = mddev->layout;
2805 		mddev->new_chunk_sectors = mddev->chunk_sectors;
2806 		mddev->raid_disks -= mddev->delta_disks;
2807 		mddev->delta_disks = 0;
2808 		module_put(pers->owner);
2809 		printk(KERN_WARNING "md: %s: %s would not accept array\n",
2810 		       mdname(mddev), level);
2811 		return PTR_ERR(priv);
2812 	}
2813 
2814 	/* Looks like we have a winner */
2815 	mddev_suspend(mddev);
2816 	mddev->pers->stop(mddev);
2817 	module_put(mddev->pers->owner);
2818 	/* Invalidate devices that are now superfluous */
2819 	list_for_each_entry(rdev, &mddev->disks, same_set)
2820 		if (rdev->raid_disk >= mddev->raid_disks) {
2821 			rdev->raid_disk = -1;
2822 			clear_bit(In_sync, &rdev->flags);
2823 		}
2824 	mddev->pers = pers;
2825 	mddev->private = priv;
2826 	strlcpy(mddev->clevel, pers->name, sizeof(mddev->clevel));
2827 	mddev->level = mddev->new_level;
2828 	mddev->layout = mddev->new_layout;
2829 	mddev->chunk_sectors = mddev->new_chunk_sectors;
2830 	mddev->delta_disks = 0;
2831 	pers->run(mddev);
2832 	mddev_resume(mddev);
2833 	set_bit(MD_CHANGE_DEVS, &mddev->flags);
2834 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
2835 	md_wakeup_thread(mddev->thread);
2836 	return rv;
2837 }
2838 
2839 static struct md_sysfs_entry md_level =
2840 __ATTR(level, S_IRUGO|S_IWUSR, level_show, level_store);
2841 
2842 
2843 static ssize_t
2844 layout_show(mddev_t *mddev, char *page)
2845 {
2846 	/* just a number, not meaningful for all levels */
2847 	if (mddev->reshape_position != MaxSector &&
2848 	    mddev->layout != mddev->new_layout)
2849 		return sprintf(page, "%d (%d)\n",
2850 			       mddev->new_layout, mddev->layout);
2851 	return sprintf(page, "%d\n", mddev->layout);
2852 }
2853 
2854 static ssize_t
2855 layout_store(mddev_t *mddev, const char *buf, size_t len)
2856 {
2857 	char *e;
2858 	unsigned long n = simple_strtoul(buf, &e, 10);
2859 
2860 	if (!*buf || (*e && *e != '\n'))
2861 		return -EINVAL;
2862 
2863 	if (mddev->pers) {
2864 		int err;
2865 		if (mddev->pers->check_reshape == NULL)
2866 			return -EBUSY;
2867 		mddev->new_layout = n;
2868 		err = mddev->pers->check_reshape(mddev);
2869 		if (err) {
2870 			mddev->new_layout = mddev->layout;
2871 			return err;
2872 		}
2873 	} else {
2874 		mddev->new_layout = n;
2875 		if (mddev->reshape_position == MaxSector)
2876 			mddev->layout = n;
2877 	}
2878 	return len;
2879 }
2880 static struct md_sysfs_entry md_layout =
2881 __ATTR(layout, S_IRUGO|S_IWUSR, layout_show, layout_store);
2882 
2883 
2884 static ssize_t
2885 raid_disks_show(mddev_t *mddev, char *page)
2886 {
2887 	if (mddev->raid_disks == 0)
2888 		return 0;
2889 	if (mddev->reshape_position != MaxSector &&
2890 	    mddev->delta_disks != 0)
2891 		return sprintf(page, "%d (%d)\n", mddev->raid_disks,
2892 			       mddev->raid_disks - mddev->delta_disks);
2893 	return sprintf(page, "%d\n", mddev->raid_disks);
2894 }
2895 
2896 static int update_raid_disks(mddev_t *mddev, int raid_disks);
2897 
2898 static ssize_t
2899 raid_disks_store(mddev_t *mddev, const char *buf, size_t len)
2900 {
2901 	char *e;
2902 	int rv = 0;
2903 	unsigned long n = simple_strtoul(buf, &e, 10);
2904 
2905 	if (!*buf || (*e && *e != '\n'))
2906 		return -EINVAL;
2907 
2908 	if (mddev->pers)
2909 		rv = update_raid_disks(mddev, n);
2910 	else if (mddev->reshape_position != MaxSector) {
2911 		int olddisks = mddev->raid_disks - mddev->delta_disks;
2912 		mddev->delta_disks = n - olddisks;
2913 		mddev->raid_disks = n;
2914 	} else
2915 		mddev->raid_disks = n;
2916 	return rv ? rv : len;
2917 }
2918 static struct md_sysfs_entry md_raid_disks =
2919 __ATTR(raid_disks, S_IRUGO|S_IWUSR, raid_disks_show, raid_disks_store);
2920 
2921 static ssize_t
2922 chunk_size_show(mddev_t *mddev, char *page)
2923 {
2924 	if (mddev->reshape_position != MaxSector &&
2925 	    mddev->chunk_sectors != mddev->new_chunk_sectors)
2926 		return sprintf(page, "%d (%d)\n",
2927 			       mddev->new_chunk_sectors << 9,
2928 			       mddev->chunk_sectors << 9);
2929 	return sprintf(page, "%d\n", mddev->chunk_sectors << 9);
2930 }
2931 
2932 static ssize_t
2933 chunk_size_store(mddev_t *mddev, const char *buf, size_t len)
2934 {
2935 	char *e;
2936 	unsigned long n = simple_strtoul(buf, &e, 10);
2937 
2938 	if (!*buf || (*e && *e != '\n'))
2939 		return -EINVAL;
2940 
2941 	if (mddev->pers) {
2942 		int err;
2943 		if (mddev->pers->check_reshape == NULL)
2944 			return -EBUSY;
2945 		mddev->new_chunk_sectors = n >> 9;
2946 		err = mddev->pers->check_reshape(mddev);
2947 		if (err) {
2948 			mddev->new_chunk_sectors = mddev->chunk_sectors;
2949 			return err;
2950 		}
2951 	} else {
2952 		mddev->new_chunk_sectors = n >> 9;
2953 		if (mddev->reshape_position == MaxSector)
2954 			mddev->chunk_sectors = n >> 9;
2955 	}
2956 	return len;
2957 }
2958 static struct md_sysfs_entry md_chunk_size =
2959 __ATTR(chunk_size, S_IRUGO|S_IWUSR, chunk_size_show, chunk_size_store);
2960 
2961 static ssize_t
2962 resync_start_show(mddev_t *mddev, char *page)
2963 {
2964 	if (mddev->recovery_cp == MaxSector)
2965 		return sprintf(page, "none\n");
2966 	return sprintf(page, "%llu\n", (unsigned long long)mddev->recovery_cp);
2967 }
2968 
2969 static ssize_t
2970 resync_start_store(mddev_t *mddev, const char *buf, size_t len)
2971 {
2972 	char *e;
2973 	unsigned long long n = simple_strtoull(buf, &e, 10);
2974 
2975 	if (mddev->pers)
2976 		return -EBUSY;
2977 	if (!*buf || (*e && *e != '\n'))
2978 		return -EINVAL;
2979 
2980 	mddev->recovery_cp = n;
2981 	return len;
2982 }
2983 static struct md_sysfs_entry md_resync_start =
2984 __ATTR(resync_start, S_IRUGO|S_IWUSR, resync_start_show, resync_start_store);
2985 
2986 /*
2987  * The array state can be:
2988  *
2989  * clear
2990  *     No devices, no size, no level
2991  *     Equivalent to STOP_ARRAY ioctl
2992  * inactive
2993  *     May have some settings, but array is not active
2994  *        all IO results in error
2995  *     When written, doesn't tear down array, but just stops it
2996  * suspended (not supported yet)
2997  *     All IO requests will block. The array can be reconfigured.
2998  *     Writing this, if accepted, will block until array is quiescent
2999  * readonly
3000  *     no resync can happen.  no superblocks get written.
3001  *     write requests fail
3002  * read-auto
3003  *     like readonly, but behaves like 'clean' on a write request.
3004  *
3005  * clean - no pending writes, but otherwise active.
3006  *     When written to inactive array, starts without resync
3007  *     If a write request arrives then
3008  *       if metadata is known, mark 'dirty' and switch to 'active'.
3009  *       if not known, block and switch to write-pending
3010  *     If written to an active array that has pending writes, then fails.
3011  * active
3012  *     fully active: IO and resync can be happening.
3013  *     When written to inactive array, starts with resync
3014  *
3015  * write-pending
3016  *     clean, but writes are blocked waiting for 'active' to be written.
3017  *
3018  * active-idle
3019  *     like active, but no writes have been seen for a while (100msec).
3020  *
3021  */
3022 enum array_state { clear, inactive, suspended, readonly, read_auto, clean, active,
3023 		   write_pending, active_idle, bad_word};
3024 static char *array_states[] = {
3025 	"clear", "inactive", "suspended", "readonly", "read-auto", "clean", "active",
3026 	"write-pending", "active-idle", NULL };
3027 
3028 static int match_word(const char *word, char **list)
3029 {
3030 	int n;
3031 	for (n=0; list[n]; n++)
3032 		if (cmd_match(word, list[n]))
3033 			break;
3034 	return n;
3035 }
3036 
3037 static ssize_t
3038 array_state_show(mddev_t *mddev, char *page)
3039 {
3040 	enum array_state st = inactive;
3041 
3042 	if (mddev->pers)
3043 		switch(mddev->ro) {
3044 		case 1:
3045 			st = readonly;
3046 			break;
3047 		case 2:
3048 			st = read_auto;
3049 			break;
3050 		case 0:
3051 			if (mddev->in_sync)
3052 				st = clean;
3053 			else if (test_bit(MD_CHANGE_CLEAN, &mddev->flags))
3054 				st = write_pending;
3055 			else if (mddev->safemode)
3056 				st = active_idle;
3057 			else
3058 				st = active;
3059 		}
3060 	else {
3061 		if (list_empty(&mddev->disks) &&
3062 		    mddev->raid_disks == 0 &&
3063 		    mddev->dev_sectors == 0)
3064 			st = clear;
3065 		else
3066 			st = inactive;
3067 	}
3068 	return sprintf(page, "%s\n", array_states[st]);
3069 }
3070 
3071 static int do_md_stop(mddev_t * mddev, int ro, int is_open);
3072 static int do_md_run(mddev_t * mddev);
3073 static int restart_array(mddev_t *mddev);
3074 
3075 static ssize_t
3076 array_state_store(mddev_t *mddev, const char *buf, size_t len)
3077 {
3078 	int err = -EINVAL;
3079 	enum array_state st = match_word(buf, array_states);
3080 	switch(st) {
3081 	case bad_word:
3082 		break;
3083 	case clear:
3084 		/* stopping an active array */
3085 		if (atomic_read(&mddev->openers) > 0)
3086 			return -EBUSY;
3087 		err = do_md_stop(mddev, 0, 0);
3088 		break;
3089 	case inactive:
3090 		/* stopping an active array */
3091 		if (mddev->pers) {
3092 			if (atomic_read(&mddev->openers) > 0)
3093 				return -EBUSY;
3094 			err = do_md_stop(mddev, 2, 0);
3095 		} else
3096 			err = 0; /* already inactive */
3097 		break;
3098 	case suspended:
3099 		break; /* not supported yet */
3100 	case readonly:
3101 		if (mddev->pers)
3102 			err = do_md_stop(mddev, 1, 0);
3103 		else {
3104 			mddev->ro = 1;
3105 			set_disk_ro(mddev->gendisk, 1);
3106 			err = do_md_run(mddev);
3107 		}
3108 		break;
3109 	case read_auto:
3110 		if (mddev->pers) {
3111 			if (mddev->ro == 0)
3112 				err = do_md_stop(mddev, 1, 0);
3113 			else if (mddev->ro == 1)
3114 				err = restart_array(mddev);
3115 			if (err == 0) {
3116 				mddev->ro = 2;
3117 				set_disk_ro(mddev->gendisk, 0);
3118 			}
3119 		} else {
3120 			mddev->ro = 2;
3121 			err = do_md_run(mddev);
3122 		}
3123 		break;
3124 	case clean:
3125 		if (mddev->pers) {
3126 			restart_array(mddev);
3127 			spin_lock_irq(&mddev->write_lock);
3128 			if (atomic_read(&mddev->writes_pending) == 0) {
3129 				if (mddev->in_sync == 0) {
3130 					mddev->in_sync = 1;
3131 					if (mddev->safemode == 1)
3132 						mddev->safemode = 0;
3133 					if (mddev->persistent)
3134 						set_bit(MD_CHANGE_CLEAN,
3135 							&mddev->flags);
3136 				}
3137 				err = 0;
3138 			} else
3139 				err = -EBUSY;
3140 			spin_unlock_irq(&mddev->write_lock);
3141 		} else
3142 			err = -EINVAL;
3143 		break;
3144 	case active:
3145 		if (mddev->pers) {
3146 			restart_array(mddev);
3147 			if (mddev->external)
3148 				clear_bit(MD_CHANGE_CLEAN, &mddev->flags);
3149 			wake_up(&mddev->sb_wait);
3150 			err = 0;
3151 		} else {
3152 			mddev->ro = 0;
3153 			set_disk_ro(mddev->gendisk, 0);
3154 			err = do_md_run(mddev);
3155 		}
3156 		break;
3157 	case write_pending:
3158 	case active_idle:
3159 		/* these cannot be set */
3160 		break;
3161 	}
3162 	if (err)
3163 		return err;
3164 	else {
3165 		sysfs_notify_dirent(mddev->sysfs_state);
3166 		return len;
3167 	}
3168 }
3169 static struct md_sysfs_entry md_array_state =
3170 __ATTR(array_state, S_IRUGO|S_IWUSR, array_state_show, array_state_store);
3171 
3172 static ssize_t
3173 null_show(mddev_t *mddev, char *page)
3174 {
3175 	return -EINVAL;
3176 }
3177 
3178 static ssize_t
3179 new_dev_store(mddev_t *mddev, const char *buf, size_t len)
3180 {
3181 	/* buf must be %d:%d\n? giving major and minor numbers */
3182 	/* The new device is added to the array.
3183 	 * If the array has a persistent superblock, we read the
3184 	 * superblock to initialise info and check validity.
3185 	 * Otherwise, only checking done is that in bind_rdev_to_array,
3186 	 * which mainly checks size.
3187 	 */
3188 	char *e;
3189 	int major = simple_strtoul(buf, &e, 10);
3190 	int minor;
3191 	dev_t dev;
3192 	mdk_rdev_t *rdev;
3193 	int err;
3194 
3195 	if (!*buf || *e != ':' || !e[1] || e[1] == '\n')
3196 		return -EINVAL;
3197 	minor = simple_strtoul(e+1, &e, 10);
3198 	if (*e && *e != '\n')
3199 		return -EINVAL;
3200 	dev = MKDEV(major, minor);
3201 	if (major != MAJOR(dev) ||
3202 	    minor != MINOR(dev))
3203 		return -EOVERFLOW;
3204 
3205 
3206 	if (mddev->persistent) {
3207 		rdev = md_import_device(dev, mddev->major_version,
3208 					mddev->minor_version);
3209 		if (!IS_ERR(rdev) && !list_empty(&mddev->disks)) {
3210 			mdk_rdev_t *rdev0 = list_entry(mddev->disks.next,
3211 						       mdk_rdev_t, same_set);
3212 			err = super_types[mddev->major_version]
3213 				.load_super(rdev, rdev0, mddev->minor_version);
3214 			if (err < 0)
3215 				goto out;
3216 		}
3217 	} else if (mddev->external)
3218 		rdev = md_import_device(dev, -2, -1);
3219 	else
3220 		rdev = md_import_device(dev, -1, -1);
3221 
3222 	if (IS_ERR(rdev))
3223 		return PTR_ERR(rdev);
3224 	err = bind_rdev_to_array(rdev, mddev);
3225  out:
3226 	if (err)
3227 		export_rdev(rdev);
3228 	return err ? err : len;
3229 }
3230 
3231 static struct md_sysfs_entry md_new_device =
3232 __ATTR(new_dev, S_IWUSR, null_show, new_dev_store);
3233 
3234 static ssize_t
3235 bitmap_store(mddev_t *mddev, const char *buf, size_t len)
3236 {
3237 	char *end;
3238 	unsigned long chunk, end_chunk;
3239 
3240 	if (!mddev->bitmap)
3241 		goto out;
3242 	/* buf should be <chunk> <chunk> ... or <chunk>-<chunk> ... (range) */
3243 	while (*buf) {
3244 		chunk = end_chunk = simple_strtoul(buf, &end, 0);
3245 		if (buf == end) break;
3246 		if (*end == '-') { /* range */
3247 			buf = end + 1;
3248 			end_chunk = simple_strtoul(buf, &end, 0);
3249 			if (buf == end) break;
3250 		}
3251 		if (*end && !isspace(*end)) break;
3252 		bitmap_dirty_bits(mddev->bitmap, chunk, end_chunk);
3253 		buf = end;
3254 		while (isspace(*buf)) buf++;
3255 	}
3256 	bitmap_unplug(mddev->bitmap); /* flush the bits to disk */
3257 out:
3258 	return len;
3259 }
3260 
3261 static struct md_sysfs_entry md_bitmap =
3262 __ATTR(bitmap_set_bits, S_IWUSR, null_show, bitmap_store);
3263 
3264 static ssize_t
3265 size_show(mddev_t *mddev, char *page)
3266 {
3267 	return sprintf(page, "%llu\n",
3268 		(unsigned long long)mddev->dev_sectors / 2);
3269 }
3270 
3271 static int update_size(mddev_t *mddev, sector_t num_sectors);
3272 
3273 static ssize_t
3274 size_store(mddev_t *mddev, const char *buf, size_t len)
3275 {
3276 	/* If array is inactive, we can reduce the component size, but
3277 	 * not increase it (except from 0).
3278 	 * If array is active, we can try an on-line resize
3279 	 */
3280 	sector_t sectors;
3281 	int err = strict_blocks_to_sectors(buf, &sectors);
3282 
3283 	if (err < 0)
3284 		return err;
3285 	if (mddev->pers) {
3286 		err = update_size(mddev, sectors);
3287 		md_update_sb(mddev, 1);
3288 	} else {
3289 		if (mddev->dev_sectors == 0 ||
3290 		    mddev->dev_sectors > sectors)
3291 			mddev->dev_sectors = sectors;
3292 		else
3293 			err = -ENOSPC;
3294 	}
3295 	return err ? err : len;
3296 }
3297 
3298 static struct md_sysfs_entry md_size =
3299 __ATTR(component_size, S_IRUGO|S_IWUSR, size_show, size_store);
3300 
3301 
3302 /* Metdata version.
3303  * This is one of
3304  *   'none' for arrays with no metadata (good luck...)
3305  *   'external' for arrays with externally managed metadata,
3306  * or N.M for internally known formats
3307  */
3308 static ssize_t
3309 metadata_show(mddev_t *mddev, char *page)
3310 {
3311 	if (mddev->persistent)
3312 		return sprintf(page, "%d.%d\n",
3313 			       mddev->major_version, mddev->minor_version);
3314 	else if (mddev->external)
3315 		return sprintf(page, "external:%s\n", mddev->metadata_type);
3316 	else
3317 		return sprintf(page, "none\n");
3318 }
3319 
3320 static ssize_t
3321 metadata_store(mddev_t *mddev, const char *buf, size_t len)
3322 {
3323 	int major, minor;
3324 	char *e;
3325 	/* Changing the details of 'external' metadata is
3326 	 * always permitted.  Otherwise there must be
3327 	 * no devices attached to the array.
3328 	 */
3329 	if (mddev->external && strncmp(buf, "external:", 9) == 0)
3330 		;
3331 	else if (!list_empty(&mddev->disks))
3332 		return -EBUSY;
3333 
3334 	if (cmd_match(buf, "none")) {
3335 		mddev->persistent = 0;
3336 		mddev->external = 0;
3337 		mddev->major_version = 0;
3338 		mddev->minor_version = 90;
3339 		return len;
3340 	}
3341 	if (strncmp(buf, "external:", 9) == 0) {
3342 		size_t namelen = len-9;
3343 		if (namelen >= sizeof(mddev->metadata_type))
3344 			namelen = sizeof(mddev->metadata_type)-1;
3345 		strncpy(mddev->metadata_type, buf+9, namelen);
3346 		mddev->metadata_type[namelen] = 0;
3347 		if (namelen && mddev->metadata_type[namelen-1] == '\n')
3348 			mddev->metadata_type[--namelen] = 0;
3349 		mddev->persistent = 0;
3350 		mddev->external = 1;
3351 		mddev->major_version = 0;
3352 		mddev->minor_version = 90;
3353 		return len;
3354 	}
3355 	major = simple_strtoul(buf, &e, 10);
3356 	if (e==buf || *e != '.')
3357 		return -EINVAL;
3358 	buf = e+1;
3359 	minor = simple_strtoul(buf, &e, 10);
3360 	if (e==buf || (*e && *e != '\n') )
3361 		return -EINVAL;
3362 	if (major >= ARRAY_SIZE(super_types) || super_types[major].name == NULL)
3363 		return -ENOENT;
3364 	mddev->major_version = major;
3365 	mddev->minor_version = minor;
3366 	mddev->persistent = 1;
3367 	mddev->external = 0;
3368 	return len;
3369 }
3370 
3371 static struct md_sysfs_entry md_metadata =
3372 __ATTR(metadata_version, S_IRUGO|S_IWUSR, metadata_show, metadata_store);
3373 
3374 static ssize_t
3375 action_show(mddev_t *mddev, char *page)
3376 {
3377 	char *type = "idle";
3378 	if (test_bit(MD_RECOVERY_FROZEN, &mddev->recovery))
3379 		type = "frozen";
3380 	else if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
3381 	    (!mddev->ro && test_bit(MD_RECOVERY_NEEDED, &mddev->recovery))) {
3382 		if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
3383 			type = "reshape";
3384 		else if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
3385 			if (!test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
3386 				type = "resync";
3387 			else if (test_bit(MD_RECOVERY_CHECK, &mddev->recovery))
3388 				type = "check";
3389 			else
3390 				type = "repair";
3391 		} else if (test_bit(MD_RECOVERY_RECOVER, &mddev->recovery))
3392 			type = "recover";
3393 	}
3394 	return sprintf(page, "%s\n", type);
3395 }
3396 
3397 static ssize_t
3398 action_store(mddev_t *mddev, const char *page, size_t len)
3399 {
3400 	if (!mddev->pers || !mddev->pers->sync_request)
3401 		return -EINVAL;
3402 
3403 	if (cmd_match(page, "frozen"))
3404 		set_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
3405 	else
3406 		clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
3407 
3408 	if (cmd_match(page, "idle") || cmd_match(page, "frozen")) {
3409 		if (mddev->sync_thread) {
3410 			set_bit(MD_RECOVERY_INTR, &mddev->recovery);
3411 			md_unregister_thread(mddev->sync_thread);
3412 			mddev->sync_thread = NULL;
3413 			mddev->recovery = 0;
3414 		}
3415 	} else if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
3416 		   test_bit(MD_RECOVERY_NEEDED, &mddev->recovery))
3417 		return -EBUSY;
3418 	else if (cmd_match(page, "resync"))
3419 		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
3420 	else if (cmd_match(page, "recover")) {
3421 		set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
3422 		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
3423 	} else if (cmd_match(page, "reshape")) {
3424 		int err;
3425 		if (mddev->pers->start_reshape == NULL)
3426 			return -EINVAL;
3427 		err = mddev->pers->start_reshape(mddev);
3428 		if (err)
3429 			return err;
3430 		sysfs_notify(&mddev->kobj, NULL, "degraded");
3431 	} else {
3432 		if (cmd_match(page, "check"))
3433 			set_bit(MD_RECOVERY_CHECK, &mddev->recovery);
3434 		else if (!cmd_match(page, "repair"))
3435 			return -EINVAL;
3436 		set_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
3437 		set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
3438 	}
3439 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
3440 	md_wakeup_thread(mddev->thread);
3441 	sysfs_notify_dirent(mddev->sysfs_action);
3442 	return len;
3443 }
3444 
3445 static ssize_t
3446 mismatch_cnt_show(mddev_t *mddev, char *page)
3447 {
3448 	return sprintf(page, "%llu\n",
3449 		       (unsigned long long) mddev->resync_mismatches);
3450 }
3451 
3452 static struct md_sysfs_entry md_scan_mode =
3453 __ATTR(sync_action, S_IRUGO|S_IWUSR, action_show, action_store);
3454 
3455 
3456 static struct md_sysfs_entry md_mismatches = __ATTR_RO(mismatch_cnt);
3457 
3458 static ssize_t
3459 sync_min_show(mddev_t *mddev, char *page)
3460 {
3461 	return sprintf(page, "%d (%s)\n", speed_min(mddev),
3462 		       mddev->sync_speed_min ? "local": "system");
3463 }
3464 
3465 static ssize_t
3466 sync_min_store(mddev_t *mddev, const char *buf, size_t len)
3467 {
3468 	int min;
3469 	char *e;
3470 	if (strncmp(buf, "system", 6)==0) {
3471 		mddev->sync_speed_min = 0;
3472 		return len;
3473 	}
3474 	min = simple_strtoul(buf, &e, 10);
3475 	if (buf == e || (*e && *e != '\n') || min <= 0)
3476 		return -EINVAL;
3477 	mddev->sync_speed_min = min;
3478 	return len;
3479 }
3480 
3481 static struct md_sysfs_entry md_sync_min =
3482 __ATTR(sync_speed_min, S_IRUGO|S_IWUSR, sync_min_show, sync_min_store);
3483 
3484 static ssize_t
3485 sync_max_show(mddev_t *mddev, char *page)
3486 {
3487 	return sprintf(page, "%d (%s)\n", speed_max(mddev),
3488 		       mddev->sync_speed_max ? "local": "system");
3489 }
3490 
3491 static ssize_t
3492 sync_max_store(mddev_t *mddev, const char *buf, size_t len)
3493 {
3494 	int max;
3495 	char *e;
3496 	if (strncmp(buf, "system", 6)==0) {
3497 		mddev->sync_speed_max = 0;
3498 		return len;
3499 	}
3500 	max = simple_strtoul(buf, &e, 10);
3501 	if (buf == e || (*e && *e != '\n') || max <= 0)
3502 		return -EINVAL;
3503 	mddev->sync_speed_max = max;
3504 	return len;
3505 }
3506 
3507 static struct md_sysfs_entry md_sync_max =
3508 __ATTR(sync_speed_max, S_IRUGO|S_IWUSR, sync_max_show, sync_max_store);
3509 
3510 static ssize_t
3511 degraded_show(mddev_t *mddev, char *page)
3512 {
3513 	return sprintf(page, "%d\n", mddev->degraded);
3514 }
3515 static struct md_sysfs_entry md_degraded = __ATTR_RO(degraded);
3516 
3517 static ssize_t
3518 sync_force_parallel_show(mddev_t *mddev, char *page)
3519 {
3520 	return sprintf(page, "%d\n", mddev->parallel_resync);
3521 }
3522 
3523 static ssize_t
3524 sync_force_parallel_store(mddev_t *mddev, const char *buf, size_t len)
3525 {
3526 	long n;
3527 
3528 	if (strict_strtol(buf, 10, &n))
3529 		return -EINVAL;
3530 
3531 	if (n != 0 && n != 1)
3532 		return -EINVAL;
3533 
3534 	mddev->parallel_resync = n;
3535 
3536 	if (mddev->sync_thread)
3537 		wake_up(&resync_wait);
3538 
3539 	return len;
3540 }
3541 
3542 /* force parallel resync, even with shared block devices */
3543 static struct md_sysfs_entry md_sync_force_parallel =
3544 __ATTR(sync_force_parallel, S_IRUGO|S_IWUSR,
3545        sync_force_parallel_show, sync_force_parallel_store);
3546 
3547 static ssize_t
3548 sync_speed_show(mddev_t *mddev, char *page)
3549 {
3550 	unsigned long resync, dt, db;
3551 	if (mddev->curr_resync == 0)
3552 		return sprintf(page, "none\n");
3553 	resync = mddev->curr_mark_cnt - atomic_read(&mddev->recovery_active);
3554 	dt = (jiffies - mddev->resync_mark) / HZ;
3555 	if (!dt) dt++;
3556 	db = resync - mddev->resync_mark_cnt;
3557 	return sprintf(page, "%lu\n", db/dt/2); /* K/sec */
3558 }
3559 
3560 static struct md_sysfs_entry md_sync_speed = __ATTR_RO(sync_speed);
3561 
3562 static ssize_t
3563 sync_completed_show(mddev_t *mddev, char *page)
3564 {
3565 	unsigned long max_sectors, resync;
3566 
3567 	if (!test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
3568 		return sprintf(page, "none\n");
3569 
3570 	if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery))
3571 		max_sectors = mddev->resync_max_sectors;
3572 	else
3573 		max_sectors = mddev->dev_sectors;
3574 
3575 	resync = mddev->curr_resync_completed;
3576 	return sprintf(page, "%lu / %lu\n", resync, max_sectors);
3577 }
3578 
3579 static struct md_sysfs_entry md_sync_completed = __ATTR_RO(sync_completed);
3580 
3581 static ssize_t
3582 min_sync_show(mddev_t *mddev, char *page)
3583 {
3584 	return sprintf(page, "%llu\n",
3585 		       (unsigned long long)mddev->resync_min);
3586 }
3587 static ssize_t
3588 min_sync_store(mddev_t *mddev, const char *buf, size_t len)
3589 {
3590 	unsigned long long min;
3591 	if (strict_strtoull(buf, 10, &min))
3592 		return -EINVAL;
3593 	if (min > mddev->resync_max)
3594 		return -EINVAL;
3595 	if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
3596 		return -EBUSY;
3597 
3598 	/* Must be a multiple of chunk_size */
3599 	if (mddev->chunk_sectors) {
3600 		sector_t temp = min;
3601 		if (sector_div(temp, mddev->chunk_sectors))
3602 			return -EINVAL;
3603 	}
3604 	mddev->resync_min = min;
3605 
3606 	return len;
3607 }
3608 
3609 static struct md_sysfs_entry md_min_sync =
3610 __ATTR(sync_min, S_IRUGO|S_IWUSR, min_sync_show, min_sync_store);
3611 
3612 static ssize_t
3613 max_sync_show(mddev_t *mddev, char *page)
3614 {
3615 	if (mddev->resync_max == MaxSector)
3616 		return sprintf(page, "max\n");
3617 	else
3618 		return sprintf(page, "%llu\n",
3619 			       (unsigned long long)mddev->resync_max);
3620 }
3621 static ssize_t
3622 max_sync_store(mddev_t *mddev, const char *buf, size_t len)
3623 {
3624 	if (strncmp(buf, "max", 3) == 0)
3625 		mddev->resync_max = MaxSector;
3626 	else {
3627 		unsigned long long max;
3628 		if (strict_strtoull(buf, 10, &max))
3629 			return -EINVAL;
3630 		if (max < mddev->resync_min)
3631 			return -EINVAL;
3632 		if (max < mddev->resync_max &&
3633 		    mddev->ro == 0 &&
3634 		    test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
3635 			return -EBUSY;
3636 
3637 		/* Must be a multiple of chunk_size */
3638 		if (mddev->chunk_sectors) {
3639 			sector_t temp = max;
3640 			if (sector_div(temp, mddev->chunk_sectors))
3641 				return -EINVAL;
3642 		}
3643 		mddev->resync_max = max;
3644 	}
3645 	wake_up(&mddev->recovery_wait);
3646 	return len;
3647 }
3648 
3649 static struct md_sysfs_entry md_max_sync =
3650 __ATTR(sync_max, S_IRUGO|S_IWUSR, max_sync_show, max_sync_store);
3651 
3652 static ssize_t
3653 suspend_lo_show(mddev_t *mddev, char *page)
3654 {
3655 	return sprintf(page, "%llu\n", (unsigned long long)mddev->suspend_lo);
3656 }
3657 
3658 static ssize_t
3659 suspend_lo_store(mddev_t *mddev, const char *buf, size_t len)
3660 {
3661 	char *e;
3662 	unsigned long long new = simple_strtoull(buf, &e, 10);
3663 
3664 	if (mddev->pers == NULL ||
3665 	    mddev->pers->quiesce == NULL)
3666 		return -EINVAL;
3667 	if (buf == e || (*e && *e != '\n'))
3668 		return -EINVAL;
3669 	if (new >= mddev->suspend_hi ||
3670 	    (new > mddev->suspend_lo && new < mddev->suspend_hi)) {
3671 		mddev->suspend_lo = new;
3672 		mddev->pers->quiesce(mddev, 2);
3673 		return len;
3674 	} else
3675 		return -EINVAL;
3676 }
3677 static struct md_sysfs_entry md_suspend_lo =
3678 __ATTR(suspend_lo, S_IRUGO|S_IWUSR, suspend_lo_show, suspend_lo_store);
3679 
3680 
3681 static ssize_t
3682 suspend_hi_show(mddev_t *mddev, char *page)
3683 {
3684 	return sprintf(page, "%llu\n", (unsigned long long)mddev->suspend_hi);
3685 }
3686 
3687 static ssize_t
3688 suspend_hi_store(mddev_t *mddev, const char *buf, size_t len)
3689 {
3690 	char *e;
3691 	unsigned long long new = simple_strtoull(buf, &e, 10);
3692 
3693 	if (mddev->pers == NULL ||
3694 	    mddev->pers->quiesce == NULL)
3695 		return -EINVAL;
3696 	if (buf == e || (*e && *e != '\n'))
3697 		return -EINVAL;
3698 	if ((new <= mddev->suspend_lo && mddev->suspend_lo >= mddev->suspend_hi) ||
3699 	    (new > mddev->suspend_lo && new > mddev->suspend_hi)) {
3700 		mddev->suspend_hi = new;
3701 		mddev->pers->quiesce(mddev, 1);
3702 		mddev->pers->quiesce(mddev, 0);
3703 		return len;
3704 	} else
3705 		return -EINVAL;
3706 }
3707 static struct md_sysfs_entry md_suspend_hi =
3708 __ATTR(suspend_hi, S_IRUGO|S_IWUSR, suspend_hi_show, suspend_hi_store);
3709 
3710 static ssize_t
3711 reshape_position_show(mddev_t *mddev, char *page)
3712 {
3713 	if (mddev->reshape_position != MaxSector)
3714 		return sprintf(page, "%llu\n",
3715 			       (unsigned long long)mddev->reshape_position);
3716 	strcpy(page, "none\n");
3717 	return 5;
3718 }
3719 
3720 static ssize_t
3721 reshape_position_store(mddev_t *mddev, const char *buf, size_t len)
3722 {
3723 	char *e;
3724 	unsigned long long new = simple_strtoull(buf, &e, 10);
3725 	if (mddev->pers)
3726 		return -EBUSY;
3727 	if (buf == e || (*e && *e != '\n'))
3728 		return -EINVAL;
3729 	mddev->reshape_position = new;
3730 	mddev->delta_disks = 0;
3731 	mddev->new_level = mddev->level;
3732 	mddev->new_layout = mddev->layout;
3733 	mddev->new_chunk_sectors = mddev->chunk_sectors;
3734 	return len;
3735 }
3736 
3737 static struct md_sysfs_entry md_reshape_position =
3738 __ATTR(reshape_position, S_IRUGO|S_IWUSR, reshape_position_show,
3739        reshape_position_store);
3740 
3741 static ssize_t
3742 array_size_show(mddev_t *mddev, char *page)
3743 {
3744 	if (mddev->external_size)
3745 		return sprintf(page, "%llu\n",
3746 			       (unsigned long long)mddev->array_sectors/2);
3747 	else
3748 		return sprintf(page, "default\n");
3749 }
3750 
3751 static ssize_t
3752 array_size_store(mddev_t *mddev, const char *buf, size_t len)
3753 {
3754 	sector_t sectors;
3755 
3756 	if (strncmp(buf, "default", 7) == 0) {
3757 		if (mddev->pers)
3758 			sectors = mddev->pers->size(mddev, 0, 0);
3759 		else
3760 			sectors = mddev->array_sectors;
3761 
3762 		mddev->external_size = 0;
3763 	} else {
3764 		if (strict_blocks_to_sectors(buf, &sectors) < 0)
3765 			return -EINVAL;
3766 		if (mddev->pers && mddev->pers->size(mddev, 0, 0) < sectors)
3767 			return -E2BIG;
3768 
3769 		mddev->external_size = 1;
3770 	}
3771 
3772 	mddev->array_sectors = sectors;
3773 	set_capacity(mddev->gendisk, mddev->array_sectors);
3774 	if (mddev->pers)
3775 		revalidate_disk(mddev->gendisk);
3776 
3777 	return len;
3778 }
3779 
3780 static struct md_sysfs_entry md_array_size =
3781 __ATTR(array_size, S_IRUGO|S_IWUSR, array_size_show,
3782        array_size_store);
3783 
3784 static struct attribute *md_default_attrs[] = {
3785 	&md_level.attr,
3786 	&md_layout.attr,
3787 	&md_raid_disks.attr,
3788 	&md_chunk_size.attr,
3789 	&md_size.attr,
3790 	&md_resync_start.attr,
3791 	&md_metadata.attr,
3792 	&md_new_device.attr,
3793 	&md_safe_delay.attr,
3794 	&md_array_state.attr,
3795 	&md_reshape_position.attr,
3796 	&md_array_size.attr,
3797 	NULL,
3798 };
3799 
3800 static struct attribute *md_redundancy_attrs[] = {
3801 	&md_scan_mode.attr,
3802 	&md_mismatches.attr,
3803 	&md_sync_min.attr,
3804 	&md_sync_max.attr,
3805 	&md_sync_speed.attr,
3806 	&md_sync_force_parallel.attr,
3807 	&md_sync_completed.attr,
3808 	&md_min_sync.attr,
3809 	&md_max_sync.attr,
3810 	&md_suspend_lo.attr,
3811 	&md_suspend_hi.attr,
3812 	&md_bitmap.attr,
3813 	&md_degraded.attr,
3814 	NULL,
3815 };
3816 static struct attribute_group md_redundancy_group = {
3817 	.name = NULL,
3818 	.attrs = md_redundancy_attrs,
3819 };
3820 
3821 
3822 static ssize_t
3823 md_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
3824 {
3825 	struct md_sysfs_entry *entry = container_of(attr, struct md_sysfs_entry, attr);
3826 	mddev_t *mddev = container_of(kobj, struct mddev_s, kobj);
3827 	ssize_t rv;
3828 
3829 	if (!entry->show)
3830 		return -EIO;
3831 	rv = mddev_lock(mddev);
3832 	if (!rv) {
3833 		rv = entry->show(mddev, page);
3834 		mddev_unlock(mddev);
3835 	}
3836 	return rv;
3837 }
3838 
3839 static ssize_t
3840 md_attr_store(struct kobject *kobj, struct attribute *attr,
3841 	      const char *page, size_t length)
3842 {
3843 	struct md_sysfs_entry *entry = container_of(attr, struct md_sysfs_entry, attr);
3844 	mddev_t *mddev = container_of(kobj, struct mddev_s, kobj);
3845 	ssize_t rv;
3846 
3847 	if (!entry->store)
3848 		return -EIO;
3849 	if (!capable(CAP_SYS_ADMIN))
3850 		return -EACCES;
3851 	rv = mddev_lock(mddev);
3852 	if (mddev->hold_active == UNTIL_IOCTL)
3853 		mddev->hold_active = 0;
3854 	if (!rv) {
3855 		rv = entry->store(mddev, page, length);
3856 		mddev_unlock(mddev);
3857 	}
3858 	return rv;
3859 }
3860 
3861 static void md_free(struct kobject *ko)
3862 {
3863 	mddev_t *mddev = container_of(ko, mddev_t, kobj);
3864 
3865 	if (mddev->sysfs_state)
3866 		sysfs_put(mddev->sysfs_state);
3867 
3868 	if (mddev->gendisk) {
3869 		del_gendisk(mddev->gendisk);
3870 		put_disk(mddev->gendisk);
3871 	}
3872 	if (mddev->queue)
3873 		blk_cleanup_queue(mddev->queue);
3874 
3875 	kfree(mddev);
3876 }
3877 
3878 static struct sysfs_ops md_sysfs_ops = {
3879 	.show	= md_attr_show,
3880 	.store	= md_attr_store,
3881 };
3882 static struct kobj_type md_ktype = {
3883 	.release	= md_free,
3884 	.sysfs_ops	= &md_sysfs_ops,
3885 	.default_attrs	= md_default_attrs,
3886 };
3887 
3888 int mdp_major = 0;
3889 
3890 static void mddev_delayed_delete(struct work_struct *ws)
3891 {
3892 	mddev_t *mddev = container_of(ws, mddev_t, del_work);
3893 
3894 	if (mddev->private == &md_redundancy_group) {
3895 		sysfs_remove_group(&mddev->kobj, &md_redundancy_group);
3896 		if (mddev->sysfs_action)
3897 			sysfs_put(mddev->sysfs_action);
3898 		mddev->sysfs_action = NULL;
3899 		mddev->private = NULL;
3900 	}
3901 	kobject_del(&mddev->kobj);
3902 	kobject_put(&mddev->kobj);
3903 }
3904 
3905 static int md_alloc(dev_t dev, char *name)
3906 {
3907 	static DEFINE_MUTEX(disks_mutex);
3908 	mddev_t *mddev = mddev_find(dev);
3909 	struct gendisk *disk;
3910 	int partitioned;
3911 	int shift;
3912 	int unit;
3913 	int error;
3914 
3915 	if (!mddev)
3916 		return -ENODEV;
3917 
3918 	partitioned = (MAJOR(mddev->unit) != MD_MAJOR);
3919 	shift = partitioned ? MdpMinorShift : 0;
3920 	unit = MINOR(mddev->unit) >> shift;
3921 
3922 	/* wait for any previous instance if this device
3923 	 * to be completed removed (mddev_delayed_delete).
3924 	 */
3925 	flush_scheduled_work();
3926 
3927 	mutex_lock(&disks_mutex);
3928 	error = -EEXIST;
3929 	if (mddev->gendisk)
3930 		goto abort;
3931 
3932 	if (name) {
3933 		/* Need to ensure that 'name' is not a duplicate.
3934 		 */
3935 		mddev_t *mddev2;
3936 		spin_lock(&all_mddevs_lock);
3937 
3938 		list_for_each_entry(mddev2, &all_mddevs, all_mddevs)
3939 			if (mddev2->gendisk &&
3940 			    strcmp(mddev2->gendisk->disk_name, name) == 0) {
3941 				spin_unlock(&all_mddevs_lock);
3942 				goto abort;
3943 			}
3944 		spin_unlock(&all_mddevs_lock);
3945 	}
3946 
3947 	error = -ENOMEM;
3948 	mddev->queue = blk_alloc_queue(GFP_KERNEL);
3949 	if (!mddev->queue)
3950 		goto abort;
3951 	mddev->queue->queuedata = mddev;
3952 
3953 	/* Can be unlocked because the queue is new: no concurrency */
3954 	queue_flag_set_unlocked(QUEUE_FLAG_CLUSTER, mddev->queue);
3955 
3956 	blk_queue_make_request(mddev->queue, md_make_request);
3957 
3958 	disk = alloc_disk(1 << shift);
3959 	if (!disk) {
3960 		blk_cleanup_queue(mddev->queue);
3961 		mddev->queue = NULL;
3962 		goto abort;
3963 	}
3964 	disk->major = MAJOR(mddev->unit);
3965 	disk->first_minor = unit << shift;
3966 	if (name)
3967 		strcpy(disk->disk_name, name);
3968 	else if (partitioned)
3969 		sprintf(disk->disk_name, "md_d%d", unit);
3970 	else
3971 		sprintf(disk->disk_name, "md%d", unit);
3972 	disk->fops = &md_fops;
3973 	disk->private_data = mddev;
3974 	disk->queue = mddev->queue;
3975 	/* Allow extended partitions.  This makes the
3976 	 * 'mdp' device redundant, but we can't really
3977 	 * remove it now.
3978 	 */
3979 	disk->flags |= GENHD_FL_EXT_DEVT;
3980 	add_disk(disk);
3981 	mddev->gendisk = disk;
3982 	error = kobject_init_and_add(&mddev->kobj, &md_ktype,
3983 				     &disk_to_dev(disk)->kobj, "%s", "md");
3984 	if (error) {
3985 		/* This isn't possible, but as kobject_init_and_add is marked
3986 		 * __must_check, we must do something with the result
3987 		 */
3988 		printk(KERN_WARNING "md: cannot register %s/md - name in use\n",
3989 		       disk->disk_name);
3990 		error = 0;
3991 	}
3992  abort:
3993 	mutex_unlock(&disks_mutex);
3994 	if (!error) {
3995 		kobject_uevent(&mddev->kobj, KOBJ_ADD);
3996 		mddev->sysfs_state = sysfs_get_dirent(mddev->kobj.sd, "array_state");
3997 	}
3998 	mddev_put(mddev);
3999 	return error;
4000 }
4001 
4002 static struct kobject *md_probe(dev_t dev, int *part, void *data)
4003 {
4004 	md_alloc(dev, NULL);
4005 	return NULL;
4006 }
4007 
4008 static int add_named_array(const char *val, struct kernel_param *kp)
4009 {
4010 	/* val must be "md_*" where * is not all digits.
4011 	 * We allocate an array with a large free minor number, and
4012 	 * set the name to val.  val must not already be an active name.
4013 	 */
4014 	int len = strlen(val);
4015 	char buf[DISK_NAME_LEN];
4016 
4017 	while (len && val[len-1] == '\n')
4018 		len--;
4019 	if (len >= DISK_NAME_LEN)
4020 		return -E2BIG;
4021 	strlcpy(buf, val, len+1);
4022 	if (strncmp(buf, "md_", 3) != 0)
4023 		return -EINVAL;
4024 	return md_alloc(0, buf);
4025 }
4026 
4027 static void md_safemode_timeout(unsigned long data)
4028 {
4029 	mddev_t *mddev = (mddev_t *) data;
4030 
4031 	if (!atomic_read(&mddev->writes_pending)) {
4032 		mddev->safemode = 1;
4033 		if (mddev->external)
4034 			sysfs_notify_dirent(mddev->sysfs_state);
4035 	}
4036 	md_wakeup_thread(mddev->thread);
4037 }
4038 
4039 static int start_dirty_degraded;
4040 
4041 static int do_md_run(mddev_t * mddev)
4042 {
4043 	int err;
4044 	mdk_rdev_t *rdev;
4045 	struct gendisk *disk;
4046 	struct mdk_personality *pers;
4047 
4048 	if (list_empty(&mddev->disks))
4049 		/* cannot run an array with no devices.. */
4050 		return -EINVAL;
4051 
4052 	if (mddev->pers)
4053 		return -EBUSY;
4054 
4055 	/*
4056 	 * Analyze all RAID superblock(s)
4057 	 */
4058 	if (!mddev->raid_disks) {
4059 		if (!mddev->persistent)
4060 			return -EINVAL;
4061 		analyze_sbs(mddev);
4062 	}
4063 
4064 	if (mddev->level != LEVEL_NONE)
4065 		request_module("md-level-%d", mddev->level);
4066 	else if (mddev->clevel[0])
4067 		request_module("md-%s", mddev->clevel);
4068 
4069 	/*
4070 	 * Drop all container device buffers, from now on
4071 	 * the only valid external interface is through the md
4072 	 * device.
4073 	 */
4074 	list_for_each_entry(rdev, &mddev->disks, same_set) {
4075 		if (test_bit(Faulty, &rdev->flags))
4076 			continue;
4077 		sync_blockdev(rdev->bdev);
4078 		invalidate_bdev(rdev->bdev);
4079 
4080 		/* perform some consistency tests on the device.
4081 		 * We don't want the data to overlap the metadata,
4082 		 * Internal Bitmap issues have been handled elsewhere.
4083 		 */
4084 		if (rdev->data_offset < rdev->sb_start) {
4085 			if (mddev->dev_sectors &&
4086 			    rdev->data_offset + mddev->dev_sectors
4087 			    > rdev->sb_start) {
4088 				printk("md: %s: data overlaps metadata\n",
4089 				       mdname(mddev));
4090 				return -EINVAL;
4091 			}
4092 		} else {
4093 			if (rdev->sb_start + rdev->sb_size/512
4094 			    > rdev->data_offset) {
4095 				printk("md: %s: metadata overlaps data\n",
4096 				       mdname(mddev));
4097 				return -EINVAL;
4098 			}
4099 		}
4100 		sysfs_notify_dirent(rdev->sysfs_state);
4101 	}
4102 
4103 	md_probe(mddev->unit, NULL, NULL);
4104 	disk = mddev->gendisk;
4105 	if (!disk)
4106 		return -ENOMEM;
4107 
4108 	spin_lock(&pers_lock);
4109 	pers = find_pers(mddev->level, mddev->clevel);
4110 	if (!pers || !try_module_get(pers->owner)) {
4111 		spin_unlock(&pers_lock);
4112 		if (mddev->level != LEVEL_NONE)
4113 			printk(KERN_WARNING "md: personality for level %d is not loaded!\n",
4114 			       mddev->level);
4115 		else
4116 			printk(KERN_WARNING "md: personality for level %s is not loaded!\n",
4117 			       mddev->clevel);
4118 		return -EINVAL;
4119 	}
4120 	mddev->pers = pers;
4121 	spin_unlock(&pers_lock);
4122 	if (mddev->level != pers->level) {
4123 		mddev->level = pers->level;
4124 		mddev->new_level = pers->level;
4125 	}
4126 	strlcpy(mddev->clevel, pers->name, sizeof(mddev->clevel));
4127 
4128 	if (mddev->reshape_position != MaxSector &&
4129 	    pers->start_reshape == NULL) {
4130 		/* This personality cannot handle reshaping... */
4131 		mddev->pers = NULL;
4132 		module_put(pers->owner);
4133 		return -EINVAL;
4134 	}
4135 
4136 	if (pers->sync_request) {
4137 		/* Warn if this is a potentially silly
4138 		 * configuration.
4139 		 */
4140 		char b[BDEVNAME_SIZE], b2[BDEVNAME_SIZE];
4141 		mdk_rdev_t *rdev2;
4142 		int warned = 0;
4143 
4144 		list_for_each_entry(rdev, &mddev->disks, same_set)
4145 			list_for_each_entry(rdev2, &mddev->disks, same_set) {
4146 				if (rdev < rdev2 &&
4147 				    rdev->bdev->bd_contains ==
4148 				    rdev2->bdev->bd_contains) {
4149 					printk(KERN_WARNING
4150 					       "%s: WARNING: %s appears to be"
4151 					       " on the same physical disk as"
4152 					       " %s.\n",
4153 					       mdname(mddev),
4154 					       bdevname(rdev->bdev,b),
4155 					       bdevname(rdev2->bdev,b2));
4156 					warned = 1;
4157 				}
4158 			}
4159 
4160 		if (warned)
4161 			printk(KERN_WARNING
4162 			       "True protection against single-disk"
4163 			       " failure might be compromised.\n");
4164 	}
4165 
4166 	mddev->recovery = 0;
4167 	/* may be over-ridden by personality */
4168 	mddev->resync_max_sectors = mddev->dev_sectors;
4169 
4170 	mddev->barriers_work = 1;
4171 	mddev->ok_start_degraded = start_dirty_degraded;
4172 
4173 	if (start_readonly)
4174 		mddev->ro = 2; /* read-only, but switch on first write */
4175 
4176 	err = mddev->pers->run(mddev);
4177 	if (err)
4178 		printk(KERN_ERR "md: pers->run() failed ...\n");
4179 	else if (mddev->pers->size(mddev, 0, 0) < mddev->array_sectors) {
4180 		WARN_ONCE(!mddev->external_size, "%s: default size too small,"
4181 			  " but 'external_size' not in effect?\n", __func__);
4182 		printk(KERN_ERR
4183 		       "md: invalid array_size %llu > default size %llu\n",
4184 		       (unsigned long long)mddev->array_sectors / 2,
4185 		       (unsigned long long)mddev->pers->size(mddev, 0, 0) / 2);
4186 		err = -EINVAL;
4187 		mddev->pers->stop(mddev);
4188 	}
4189 	if (err == 0 && mddev->pers->sync_request) {
4190 		err = bitmap_create(mddev);
4191 		if (err) {
4192 			printk(KERN_ERR "%s: failed to create bitmap (%d)\n",
4193 			       mdname(mddev), err);
4194 			mddev->pers->stop(mddev);
4195 		}
4196 	}
4197 	if (err) {
4198 		module_put(mddev->pers->owner);
4199 		mddev->pers = NULL;
4200 		bitmap_destroy(mddev);
4201 		return err;
4202 	}
4203 	if (mddev->pers->sync_request) {
4204 		if (sysfs_create_group(&mddev->kobj, &md_redundancy_group))
4205 			printk(KERN_WARNING
4206 			       "md: cannot register extra attributes for %s\n",
4207 			       mdname(mddev));
4208 		mddev->sysfs_action = sysfs_get_dirent(mddev->kobj.sd, "sync_action");
4209 	} else if (mddev->ro == 2) /* auto-readonly not meaningful */
4210 		mddev->ro = 0;
4211 
4212  	atomic_set(&mddev->writes_pending,0);
4213 	mddev->safemode = 0;
4214 	mddev->safemode_timer.function = md_safemode_timeout;
4215 	mddev->safemode_timer.data = (unsigned long) mddev;
4216 	mddev->safemode_delay = (200 * HZ)/1000 +1; /* 200 msec delay */
4217 	mddev->in_sync = 1;
4218 
4219 	list_for_each_entry(rdev, &mddev->disks, same_set)
4220 		if (rdev->raid_disk >= 0) {
4221 			char nm[20];
4222 			sprintf(nm, "rd%d", rdev->raid_disk);
4223 			if (sysfs_create_link(&mddev->kobj, &rdev->kobj, nm))
4224 				printk("md: cannot register %s for %s\n",
4225 				       nm, mdname(mddev));
4226 		}
4227 
4228 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
4229 
4230 	if (mddev->flags)
4231 		md_update_sb(mddev, 0);
4232 
4233 	set_capacity(disk, mddev->array_sectors);
4234 
4235 	/* If there is a partially-recovered drive we need to
4236 	 * start recovery here.  If we leave it to md_check_recovery,
4237 	 * it will remove the drives and not do the right thing
4238 	 */
4239 	if (mddev->degraded && !mddev->sync_thread) {
4240 		int spares = 0;
4241 		list_for_each_entry(rdev, &mddev->disks, same_set)
4242 			if (rdev->raid_disk >= 0 &&
4243 			    !test_bit(In_sync, &rdev->flags) &&
4244 			    !test_bit(Faulty, &rdev->flags))
4245 				/* complete an interrupted recovery */
4246 				spares++;
4247 		if (spares && mddev->pers->sync_request) {
4248 			mddev->recovery = 0;
4249 			set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
4250 			mddev->sync_thread = md_register_thread(md_do_sync,
4251 								mddev,
4252 								"resync");
4253 			if (!mddev->sync_thread) {
4254 				printk(KERN_ERR "%s: could not start resync"
4255 				       " thread...\n",
4256 				       mdname(mddev));
4257 				/* leave the spares where they are, it shouldn't hurt */
4258 				mddev->recovery = 0;
4259 			}
4260 		}
4261 	}
4262 	md_wakeup_thread(mddev->thread);
4263 	md_wakeup_thread(mddev->sync_thread); /* possibly kick off a reshape */
4264 
4265 	revalidate_disk(mddev->gendisk);
4266 	mddev->changed = 1;
4267 	md_new_event(mddev);
4268 	sysfs_notify_dirent(mddev->sysfs_state);
4269 	if (mddev->sysfs_action)
4270 		sysfs_notify_dirent(mddev->sysfs_action);
4271 	sysfs_notify(&mddev->kobj, NULL, "degraded");
4272 	kobject_uevent(&disk_to_dev(mddev->gendisk)->kobj, KOBJ_CHANGE);
4273 	return 0;
4274 }
4275 
4276 static int restart_array(mddev_t *mddev)
4277 {
4278 	struct gendisk *disk = mddev->gendisk;
4279 
4280 	/* Complain if it has no devices */
4281 	if (list_empty(&mddev->disks))
4282 		return -ENXIO;
4283 	if (!mddev->pers)
4284 		return -EINVAL;
4285 	if (!mddev->ro)
4286 		return -EBUSY;
4287 	mddev->safemode = 0;
4288 	mddev->ro = 0;
4289 	set_disk_ro(disk, 0);
4290 	printk(KERN_INFO "md: %s switched to read-write mode.\n",
4291 		mdname(mddev));
4292 	/* Kick recovery or resync if necessary */
4293 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
4294 	md_wakeup_thread(mddev->thread);
4295 	md_wakeup_thread(mddev->sync_thread);
4296 	sysfs_notify_dirent(mddev->sysfs_state);
4297 	return 0;
4298 }
4299 
4300 /* similar to deny_write_access, but accounts for our holding a reference
4301  * to the file ourselves */
4302 static int deny_bitmap_write_access(struct file * file)
4303 {
4304 	struct inode *inode = file->f_mapping->host;
4305 
4306 	spin_lock(&inode->i_lock);
4307 	if (atomic_read(&inode->i_writecount) > 1) {
4308 		spin_unlock(&inode->i_lock);
4309 		return -ETXTBSY;
4310 	}
4311 	atomic_set(&inode->i_writecount, -1);
4312 	spin_unlock(&inode->i_lock);
4313 
4314 	return 0;
4315 }
4316 
4317 static void restore_bitmap_write_access(struct file *file)
4318 {
4319 	struct inode *inode = file->f_mapping->host;
4320 
4321 	spin_lock(&inode->i_lock);
4322 	atomic_set(&inode->i_writecount, 1);
4323 	spin_unlock(&inode->i_lock);
4324 }
4325 
4326 /* mode:
4327  *   0 - completely stop and dis-assemble array
4328  *   1 - switch to readonly
4329  *   2 - stop but do not disassemble array
4330  */
4331 static int do_md_stop(mddev_t * mddev, int mode, int is_open)
4332 {
4333 	int err = 0;
4334 	struct gendisk *disk = mddev->gendisk;
4335 	mdk_rdev_t *rdev;
4336 
4337 	mutex_lock(&mddev->open_mutex);
4338 	if (atomic_read(&mddev->openers) > is_open) {
4339 		printk("md: %s still in use.\n",mdname(mddev));
4340 		err = -EBUSY;
4341 	} else if (mddev->pers) {
4342 
4343 		if (mddev->sync_thread) {
4344 			set_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
4345 			set_bit(MD_RECOVERY_INTR, &mddev->recovery);
4346 			md_unregister_thread(mddev->sync_thread);
4347 			mddev->sync_thread = NULL;
4348 		}
4349 
4350 		del_timer_sync(&mddev->safemode_timer);
4351 
4352 		switch(mode) {
4353 		case 1: /* readonly */
4354 			err  = -ENXIO;
4355 			if (mddev->ro==1)
4356 				goto out;
4357 			mddev->ro = 1;
4358 			break;
4359 		case 0: /* disassemble */
4360 		case 2: /* stop */
4361 			bitmap_flush(mddev);
4362 			md_super_wait(mddev);
4363 			if (mddev->ro)
4364 				set_disk_ro(disk, 0);
4365 
4366 			mddev->pers->stop(mddev);
4367 			mddev->queue->merge_bvec_fn = NULL;
4368 			mddev->queue->unplug_fn = NULL;
4369 			mddev->queue->backing_dev_info.congested_fn = NULL;
4370 			module_put(mddev->pers->owner);
4371 			if (mddev->pers->sync_request)
4372 				mddev->private = &md_redundancy_group;
4373 			mddev->pers = NULL;
4374 			/* tell userspace to handle 'inactive' */
4375 			sysfs_notify_dirent(mddev->sysfs_state);
4376 
4377 			list_for_each_entry(rdev, &mddev->disks, same_set)
4378 				if (rdev->raid_disk >= 0) {
4379 					char nm[20];
4380 					sprintf(nm, "rd%d", rdev->raid_disk);
4381 					sysfs_remove_link(&mddev->kobj, nm);
4382 				}
4383 
4384 			set_capacity(disk, 0);
4385 			mddev->changed = 1;
4386 
4387 			if (mddev->ro)
4388 				mddev->ro = 0;
4389 		}
4390 		if (!mddev->in_sync || mddev->flags) {
4391 			/* mark array as shutdown cleanly */
4392 			mddev->in_sync = 1;
4393 			md_update_sb(mddev, 1);
4394 		}
4395 		if (mode == 1)
4396 			set_disk_ro(disk, 1);
4397 		clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
4398 		err = 0;
4399 	}
4400 out:
4401 	mutex_unlock(&mddev->open_mutex);
4402 	if (err)
4403 		return err;
4404 	/*
4405 	 * Free resources if final stop
4406 	 */
4407 	if (mode == 0) {
4408 
4409 		printk(KERN_INFO "md: %s stopped.\n", mdname(mddev));
4410 
4411 		bitmap_destroy(mddev);
4412 		if (mddev->bitmap_file) {
4413 			restore_bitmap_write_access(mddev->bitmap_file);
4414 			fput(mddev->bitmap_file);
4415 			mddev->bitmap_file = NULL;
4416 		}
4417 		mddev->bitmap_offset = 0;
4418 
4419 		/* make sure all md_delayed_delete calls have finished */
4420 		flush_scheduled_work();
4421 
4422 		export_array(mddev);
4423 
4424 		mddev->array_sectors = 0;
4425 		mddev->external_size = 0;
4426 		mddev->dev_sectors = 0;
4427 		mddev->raid_disks = 0;
4428 		mddev->recovery_cp = 0;
4429 		mddev->resync_min = 0;
4430 		mddev->resync_max = MaxSector;
4431 		mddev->reshape_position = MaxSector;
4432 		mddev->external = 0;
4433 		mddev->persistent = 0;
4434 		mddev->level = LEVEL_NONE;
4435 		mddev->clevel[0] = 0;
4436 		mddev->flags = 0;
4437 		mddev->ro = 0;
4438 		mddev->metadata_type[0] = 0;
4439 		mddev->chunk_sectors = 0;
4440 		mddev->ctime = mddev->utime = 0;
4441 		mddev->layout = 0;
4442 		mddev->max_disks = 0;
4443 		mddev->events = 0;
4444 		mddev->delta_disks = 0;
4445 		mddev->new_level = LEVEL_NONE;
4446 		mddev->new_layout = 0;
4447 		mddev->new_chunk_sectors = 0;
4448 		mddev->curr_resync = 0;
4449 		mddev->resync_mismatches = 0;
4450 		mddev->suspend_lo = mddev->suspend_hi = 0;
4451 		mddev->sync_speed_min = mddev->sync_speed_max = 0;
4452 		mddev->recovery = 0;
4453 		mddev->in_sync = 0;
4454 		mddev->changed = 0;
4455 		mddev->degraded = 0;
4456 		mddev->barriers_work = 0;
4457 		mddev->safemode = 0;
4458 		kobject_uevent(&disk_to_dev(mddev->gendisk)->kobj, KOBJ_CHANGE);
4459 		if (mddev->hold_active == UNTIL_STOP)
4460 			mddev->hold_active = 0;
4461 
4462 	} else if (mddev->pers)
4463 		printk(KERN_INFO "md: %s switched to read-only mode.\n",
4464 			mdname(mddev));
4465 	err = 0;
4466 	blk_integrity_unregister(disk);
4467 	md_new_event(mddev);
4468 	sysfs_notify_dirent(mddev->sysfs_state);
4469 	return err;
4470 }
4471 
4472 #ifndef MODULE
4473 static void autorun_array(mddev_t *mddev)
4474 {
4475 	mdk_rdev_t *rdev;
4476 	int err;
4477 
4478 	if (list_empty(&mddev->disks))
4479 		return;
4480 
4481 	printk(KERN_INFO "md: running: ");
4482 
4483 	list_for_each_entry(rdev, &mddev->disks, same_set) {
4484 		char b[BDEVNAME_SIZE];
4485 		printk("<%s>", bdevname(rdev->bdev,b));
4486 	}
4487 	printk("\n");
4488 
4489 	err = do_md_run(mddev);
4490 	if (err) {
4491 		printk(KERN_WARNING "md: do_md_run() returned %d\n", err);
4492 		do_md_stop(mddev, 0, 0);
4493 	}
4494 }
4495 
4496 /*
4497  * lets try to run arrays based on all disks that have arrived
4498  * until now. (those are in pending_raid_disks)
4499  *
4500  * the method: pick the first pending disk, collect all disks with
4501  * the same UUID, remove all from the pending list and put them into
4502  * the 'same_array' list. Then order this list based on superblock
4503  * update time (freshest comes first), kick out 'old' disks and
4504  * compare superblocks. If everything's fine then run it.
4505  *
4506  * If "unit" is allocated, then bump its reference count
4507  */
4508 static void autorun_devices(int part)
4509 {
4510 	mdk_rdev_t *rdev0, *rdev, *tmp;
4511 	mddev_t *mddev;
4512 	char b[BDEVNAME_SIZE];
4513 
4514 	printk(KERN_INFO "md: autorun ...\n");
4515 	while (!list_empty(&pending_raid_disks)) {
4516 		int unit;
4517 		dev_t dev;
4518 		LIST_HEAD(candidates);
4519 		rdev0 = list_entry(pending_raid_disks.next,
4520 					 mdk_rdev_t, same_set);
4521 
4522 		printk(KERN_INFO "md: considering %s ...\n",
4523 			bdevname(rdev0->bdev,b));
4524 		INIT_LIST_HEAD(&candidates);
4525 		rdev_for_each_list(rdev, tmp, &pending_raid_disks)
4526 			if (super_90_load(rdev, rdev0, 0) >= 0) {
4527 				printk(KERN_INFO "md:  adding %s ...\n",
4528 					bdevname(rdev->bdev,b));
4529 				list_move(&rdev->same_set, &candidates);
4530 			}
4531 		/*
4532 		 * now we have a set of devices, with all of them having
4533 		 * mostly sane superblocks. It's time to allocate the
4534 		 * mddev.
4535 		 */
4536 		if (part) {
4537 			dev = MKDEV(mdp_major,
4538 				    rdev0->preferred_minor << MdpMinorShift);
4539 			unit = MINOR(dev) >> MdpMinorShift;
4540 		} else {
4541 			dev = MKDEV(MD_MAJOR, rdev0->preferred_minor);
4542 			unit = MINOR(dev);
4543 		}
4544 		if (rdev0->preferred_minor != unit) {
4545 			printk(KERN_INFO "md: unit number in %s is bad: %d\n",
4546 			       bdevname(rdev0->bdev, b), rdev0->preferred_minor);
4547 			break;
4548 		}
4549 
4550 		md_probe(dev, NULL, NULL);
4551 		mddev = mddev_find(dev);
4552 		if (!mddev || !mddev->gendisk) {
4553 			if (mddev)
4554 				mddev_put(mddev);
4555 			printk(KERN_ERR
4556 				"md: cannot allocate memory for md drive.\n");
4557 			break;
4558 		}
4559 		if (mddev_lock(mddev))
4560 			printk(KERN_WARNING "md: %s locked, cannot run\n",
4561 			       mdname(mddev));
4562 		else if (mddev->raid_disks || mddev->major_version
4563 			 || !list_empty(&mddev->disks)) {
4564 			printk(KERN_WARNING
4565 				"md: %s already running, cannot run %s\n",
4566 				mdname(mddev), bdevname(rdev0->bdev,b));
4567 			mddev_unlock(mddev);
4568 		} else {
4569 			printk(KERN_INFO "md: created %s\n", mdname(mddev));
4570 			mddev->persistent = 1;
4571 			rdev_for_each_list(rdev, tmp, &candidates) {
4572 				list_del_init(&rdev->same_set);
4573 				if (bind_rdev_to_array(rdev, mddev))
4574 					export_rdev(rdev);
4575 			}
4576 			autorun_array(mddev);
4577 			mddev_unlock(mddev);
4578 		}
4579 		/* on success, candidates will be empty, on error
4580 		 * it won't...
4581 		 */
4582 		rdev_for_each_list(rdev, tmp, &candidates) {
4583 			list_del_init(&rdev->same_set);
4584 			export_rdev(rdev);
4585 		}
4586 		mddev_put(mddev);
4587 	}
4588 	printk(KERN_INFO "md: ... autorun DONE.\n");
4589 }
4590 #endif /* !MODULE */
4591 
4592 static int get_version(void __user * arg)
4593 {
4594 	mdu_version_t ver;
4595 
4596 	ver.major = MD_MAJOR_VERSION;
4597 	ver.minor = MD_MINOR_VERSION;
4598 	ver.patchlevel = MD_PATCHLEVEL_VERSION;
4599 
4600 	if (copy_to_user(arg, &ver, sizeof(ver)))
4601 		return -EFAULT;
4602 
4603 	return 0;
4604 }
4605 
4606 static int get_array_info(mddev_t * mddev, void __user * arg)
4607 {
4608 	mdu_array_info_t info;
4609 	int nr,working,insync,failed,spare;
4610 	mdk_rdev_t *rdev;
4611 
4612 	nr=working=insync=failed=spare=0;
4613 	list_for_each_entry(rdev, &mddev->disks, same_set) {
4614 		nr++;
4615 		if (test_bit(Faulty, &rdev->flags))
4616 			failed++;
4617 		else {
4618 			working++;
4619 			if (test_bit(In_sync, &rdev->flags))
4620 				insync++;
4621 			else
4622 				spare++;
4623 		}
4624 	}
4625 
4626 	info.major_version = mddev->major_version;
4627 	info.minor_version = mddev->minor_version;
4628 	info.patch_version = MD_PATCHLEVEL_VERSION;
4629 	info.ctime         = mddev->ctime;
4630 	info.level         = mddev->level;
4631 	info.size          = mddev->dev_sectors / 2;
4632 	if (info.size != mddev->dev_sectors / 2) /* overflow */
4633 		info.size = -1;
4634 	info.nr_disks      = nr;
4635 	info.raid_disks    = mddev->raid_disks;
4636 	info.md_minor      = mddev->md_minor;
4637 	info.not_persistent= !mddev->persistent;
4638 
4639 	info.utime         = mddev->utime;
4640 	info.state         = 0;
4641 	if (mddev->in_sync)
4642 		info.state = (1<<MD_SB_CLEAN);
4643 	if (mddev->bitmap && mddev->bitmap_offset)
4644 		info.state = (1<<MD_SB_BITMAP_PRESENT);
4645 	info.active_disks  = insync;
4646 	info.working_disks = working;
4647 	info.failed_disks  = failed;
4648 	info.spare_disks   = spare;
4649 
4650 	info.layout        = mddev->layout;
4651 	info.chunk_size    = mddev->chunk_sectors << 9;
4652 
4653 	if (copy_to_user(arg, &info, sizeof(info)))
4654 		return -EFAULT;
4655 
4656 	return 0;
4657 }
4658 
4659 static int get_bitmap_file(mddev_t * mddev, void __user * arg)
4660 {
4661 	mdu_bitmap_file_t *file = NULL; /* too big for stack allocation */
4662 	char *ptr, *buf = NULL;
4663 	int err = -ENOMEM;
4664 
4665 	if (md_allow_write(mddev))
4666 		file = kmalloc(sizeof(*file), GFP_NOIO);
4667 	else
4668 		file = kmalloc(sizeof(*file), GFP_KERNEL);
4669 
4670 	if (!file)
4671 		goto out;
4672 
4673 	/* bitmap disabled, zero the first byte and copy out */
4674 	if (!mddev->bitmap || !mddev->bitmap->file) {
4675 		file->pathname[0] = '\0';
4676 		goto copy_out;
4677 	}
4678 
4679 	buf = kmalloc(sizeof(file->pathname), GFP_KERNEL);
4680 	if (!buf)
4681 		goto out;
4682 
4683 	ptr = d_path(&mddev->bitmap->file->f_path, buf, sizeof(file->pathname));
4684 	if (IS_ERR(ptr))
4685 		goto out;
4686 
4687 	strcpy(file->pathname, ptr);
4688 
4689 copy_out:
4690 	err = 0;
4691 	if (copy_to_user(arg, file, sizeof(*file)))
4692 		err = -EFAULT;
4693 out:
4694 	kfree(buf);
4695 	kfree(file);
4696 	return err;
4697 }
4698 
4699 static int get_disk_info(mddev_t * mddev, void __user * arg)
4700 {
4701 	mdu_disk_info_t info;
4702 	mdk_rdev_t *rdev;
4703 
4704 	if (copy_from_user(&info, arg, sizeof(info)))
4705 		return -EFAULT;
4706 
4707 	rdev = find_rdev_nr(mddev, info.number);
4708 	if (rdev) {
4709 		info.major = MAJOR(rdev->bdev->bd_dev);
4710 		info.minor = MINOR(rdev->bdev->bd_dev);
4711 		info.raid_disk = rdev->raid_disk;
4712 		info.state = 0;
4713 		if (test_bit(Faulty, &rdev->flags))
4714 			info.state |= (1<<MD_DISK_FAULTY);
4715 		else if (test_bit(In_sync, &rdev->flags)) {
4716 			info.state |= (1<<MD_DISK_ACTIVE);
4717 			info.state |= (1<<MD_DISK_SYNC);
4718 		}
4719 		if (test_bit(WriteMostly, &rdev->flags))
4720 			info.state |= (1<<MD_DISK_WRITEMOSTLY);
4721 	} else {
4722 		info.major = info.minor = 0;
4723 		info.raid_disk = -1;
4724 		info.state = (1<<MD_DISK_REMOVED);
4725 	}
4726 
4727 	if (copy_to_user(arg, &info, sizeof(info)))
4728 		return -EFAULT;
4729 
4730 	return 0;
4731 }
4732 
4733 static int add_new_disk(mddev_t * mddev, mdu_disk_info_t *info)
4734 {
4735 	char b[BDEVNAME_SIZE], b2[BDEVNAME_SIZE];
4736 	mdk_rdev_t *rdev;
4737 	dev_t dev = MKDEV(info->major,info->minor);
4738 
4739 	if (info->major != MAJOR(dev) || info->minor != MINOR(dev))
4740 		return -EOVERFLOW;
4741 
4742 	if (!mddev->raid_disks) {
4743 		int err;
4744 		/* expecting a device which has a superblock */
4745 		rdev = md_import_device(dev, mddev->major_version, mddev->minor_version);
4746 		if (IS_ERR(rdev)) {
4747 			printk(KERN_WARNING
4748 				"md: md_import_device returned %ld\n",
4749 				PTR_ERR(rdev));
4750 			return PTR_ERR(rdev);
4751 		}
4752 		if (!list_empty(&mddev->disks)) {
4753 			mdk_rdev_t *rdev0 = list_entry(mddev->disks.next,
4754 							mdk_rdev_t, same_set);
4755 			err = super_types[mddev->major_version]
4756 				.load_super(rdev, rdev0, mddev->minor_version);
4757 			if (err < 0) {
4758 				printk(KERN_WARNING
4759 					"md: %s has different UUID to %s\n",
4760 					bdevname(rdev->bdev,b),
4761 					bdevname(rdev0->bdev,b2));
4762 				export_rdev(rdev);
4763 				return -EINVAL;
4764 			}
4765 		}
4766 		err = bind_rdev_to_array(rdev, mddev);
4767 		if (err)
4768 			export_rdev(rdev);
4769 		return err;
4770 	}
4771 
4772 	/*
4773 	 * add_new_disk can be used once the array is assembled
4774 	 * to add "hot spares".  They must already have a superblock
4775 	 * written
4776 	 */
4777 	if (mddev->pers) {
4778 		int err;
4779 		if (!mddev->pers->hot_add_disk) {
4780 			printk(KERN_WARNING
4781 				"%s: personality does not support diskops!\n",
4782 			       mdname(mddev));
4783 			return -EINVAL;
4784 		}
4785 		if (mddev->persistent)
4786 			rdev = md_import_device(dev, mddev->major_version,
4787 						mddev->minor_version);
4788 		else
4789 			rdev = md_import_device(dev, -1, -1);
4790 		if (IS_ERR(rdev)) {
4791 			printk(KERN_WARNING
4792 				"md: md_import_device returned %ld\n",
4793 				PTR_ERR(rdev));
4794 			return PTR_ERR(rdev);
4795 		}
4796 		/* set save_raid_disk if appropriate */
4797 		if (!mddev->persistent) {
4798 			if (info->state & (1<<MD_DISK_SYNC)  &&
4799 			    info->raid_disk < mddev->raid_disks)
4800 				rdev->raid_disk = info->raid_disk;
4801 			else
4802 				rdev->raid_disk = -1;
4803 		} else
4804 			super_types[mddev->major_version].
4805 				validate_super(mddev, rdev);
4806 		rdev->saved_raid_disk = rdev->raid_disk;
4807 
4808 		clear_bit(In_sync, &rdev->flags); /* just to be sure */
4809 		if (info->state & (1<<MD_DISK_WRITEMOSTLY))
4810 			set_bit(WriteMostly, &rdev->flags);
4811 		else
4812 			clear_bit(WriteMostly, &rdev->flags);
4813 
4814 		rdev->raid_disk = -1;
4815 		err = bind_rdev_to_array(rdev, mddev);
4816 		if (!err && !mddev->pers->hot_remove_disk) {
4817 			/* If there is hot_add_disk but no hot_remove_disk
4818 			 * then added disks for geometry changes,
4819 			 * and should be added immediately.
4820 			 */
4821 			super_types[mddev->major_version].
4822 				validate_super(mddev, rdev);
4823 			err = mddev->pers->hot_add_disk(mddev, rdev);
4824 			if (err)
4825 				unbind_rdev_from_array(rdev);
4826 		}
4827 		if (err)
4828 			export_rdev(rdev);
4829 		else
4830 			sysfs_notify_dirent(rdev->sysfs_state);
4831 
4832 		md_update_sb(mddev, 1);
4833 		if (mddev->degraded)
4834 			set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
4835 		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
4836 		md_wakeup_thread(mddev->thread);
4837 		return err;
4838 	}
4839 
4840 	/* otherwise, add_new_disk is only allowed
4841 	 * for major_version==0 superblocks
4842 	 */
4843 	if (mddev->major_version != 0) {
4844 		printk(KERN_WARNING "%s: ADD_NEW_DISK not supported\n",
4845 		       mdname(mddev));
4846 		return -EINVAL;
4847 	}
4848 
4849 	if (!(info->state & (1<<MD_DISK_FAULTY))) {
4850 		int err;
4851 		rdev = md_import_device(dev, -1, 0);
4852 		if (IS_ERR(rdev)) {
4853 			printk(KERN_WARNING
4854 				"md: error, md_import_device() returned %ld\n",
4855 				PTR_ERR(rdev));
4856 			return PTR_ERR(rdev);
4857 		}
4858 		rdev->desc_nr = info->number;
4859 		if (info->raid_disk < mddev->raid_disks)
4860 			rdev->raid_disk = info->raid_disk;
4861 		else
4862 			rdev->raid_disk = -1;
4863 
4864 		if (rdev->raid_disk < mddev->raid_disks)
4865 			if (info->state & (1<<MD_DISK_SYNC))
4866 				set_bit(In_sync, &rdev->flags);
4867 
4868 		if (info->state & (1<<MD_DISK_WRITEMOSTLY))
4869 			set_bit(WriteMostly, &rdev->flags);
4870 
4871 		if (!mddev->persistent) {
4872 			printk(KERN_INFO "md: nonpersistent superblock ...\n");
4873 			rdev->sb_start = rdev->bdev->bd_inode->i_size / 512;
4874 		} else
4875 			rdev->sb_start = calc_dev_sboffset(rdev->bdev);
4876 		rdev->sectors = rdev->sb_start;
4877 
4878 		err = bind_rdev_to_array(rdev, mddev);
4879 		if (err) {
4880 			export_rdev(rdev);
4881 			return err;
4882 		}
4883 	}
4884 
4885 	return 0;
4886 }
4887 
4888 static int hot_remove_disk(mddev_t * mddev, dev_t dev)
4889 {
4890 	char b[BDEVNAME_SIZE];
4891 	mdk_rdev_t *rdev;
4892 
4893 	rdev = find_rdev(mddev, dev);
4894 	if (!rdev)
4895 		return -ENXIO;
4896 
4897 	if (rdev->raid_disk >= 0)
4898 		goto busy;
4899 
4900 	kick_rdev_from_array(rdev);
4901 	md_update_sb(mddev, 1);
4902 	md_new_event(mddev);
4903 
4904 	return 0;
4905 busy:
4906 	printk(KERN_WARNING "md: cannot remove active disk %s from %s ...\n",
4907 		bdevname(rdev->bdev,b), mdname(mddev));
4908 	return -EBUSY;
4909 }
4910 
4911 static int hot_add_disk(mddev_t * mddev, dev_t dev)
4912 {
4913 	char b[BDEVNAME_SIZE];
4914 	int err;
4915 	mdk_rdev_t *rdev;
4916 
4917 	if (!mddev->pers)
4918 		return -ENODEV;
4919 
4920 	if (mddev->major_version != 0) {
4921 		printk(KERN_WARNING "%s: HOT_ADD may only be used with"
4922 			" version-0 superblocks.\n",
4923 			mdname(mddev));
4924 		return -EINVAL;
4925 	}
4926 	if (!mddev->pers->hot_add_disk) {
4927 		printk(KERN_WARNING
4928 			"%s: personality does not support diskops!\n",
4929 			mdname(mddev));
4930 		return -EINVAL;
4931 	}
4932 
4933 	rdev = md_import_device(dev, -1, 0);
4934 	if (IS_ERR(rdev)) {
4935 		printk(KERN_WARNING
4936 			"md: error, md_import_device() returned %ld\n",
4937 			PTR_ERR(rdev));
4938 		return -EINVAL;
4939 	}
4940 
4941 	if (mddev->persistent)
4942 		rdev->sb_start = calc_dev_sboffset(rdev->bdev);
4943 	else
4944 		rdev->sb_start = rdev->bdev->bd_inode->i_size / 512;
4945 
4946 	rdev->sectors = rdev->sb_start;
4947 
4948 	if (test_bit(Faulty, &rdev->flags)) {
4949 		printk(KERN_WARNING
4950 			"md: can not hot-add faulty %s disk to %s!\n",
4951 			bdevname(rdev->bdev,b), mdname(mddev));
4952 		err = -EINVAL;
4953 		goto abort_export;
4954 	}
4955 	clear_bit(In_sync, &rdev->flags);
4956 	rdev->desc_nr = -1;
4957 	rdev->saved_raid_disk = -1;
4958 	err = bind_rdev_to_array(rdev, mddev);
4959 	if (err)
4960 		goto abort_export;
4961 
4962 	/*
4963 	 * The rest should better be atomic, we can have disk failures
4964 	 * noticed in interrupt contexts ...
4965 	 */
4966 
4967 	rdev->raid_disk = -1;
4968 
4969 	md_update_sb(mddev, 1);
4970 
4971 	/*
4972 	 * Kick recovery, maybe this spare has to be added to the
4973 	 * array immediately.
4974 	 */
4975 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
4976 	md_wakeup_thread(mddev->thread);
4977 	md_new_event(mddev);
4978 	return 0;
4979 
4980 abort_export:
4981 	export_rdev(rdev);
4982 	return err;
4983 }
4984 
4985 static int set_bitmap_file(mddev_t *mddev, int fd)
4986 {
4987 	int err;
4988 
4989 	if (mddev->pers) {
4990 		if (!mddev->pers->quiesce)
4991 			return -EBUSY;
4992 		if (mddev->recovery || mddev->sync_thread)
4993 			return -EBUSY;
4994 		/* we should be able to change the bitmap.. */
4995 	}
4996 
4997 
4998 	if (fd >= 0) {
4999 		if (mddev->bitmap)
5000 			return -EEXIST; /* cannot add when bitmap is present */
5001 		mddev->bitmap_file = fget(fd);
5002 
5003 		if (mddev->bitmap_file == NULL) {
5004 			printk(KERN_ERR "%s: error: failed to get bitmap file\n",
5005 			       mdname(mddev));
5006 			return -EBADF;
5007 		}
5008 
5009 		err = deny_bitmap_write_access(mddev->bitmap_file);
5010 		if (err) {
5011 			printk(KERN_ERR "%s: error: bitmap file is already in use\n",
5012 			       mdname(mddev));
5013 			fput(mddev->bitmap_file);
5014 			mddev->bitmap_file = NULL;
5015 			return err;
5016 		}
5017 		mddev->bitmap_offset = 0; /* file overrides offset */
5018 	} else if (mddev->bitmap == NULL)
5019 		return -ENOENT; /* cannot remove what isn't there */
5020 	err = 0;
5021 	if (mddev->pers) {
5022 		mddev->pers->quiesce(mddev, 1);
5023 		if (fd >= 0)
5024 			err = bitmap_create(mddev);
5025 		if (fd < 0 || err) {
5026 			bitmap_destroy(mddev);
5027 			fd = -1; /* make sure to put the file */
5028 		}
5029 		mddev->pers->quiesce(mddev, 0);
5030 	}
5031 	if (fd < 0) {
5032 		if (mddev->bitmap_file) {
5033 			restore_bitmap_write_access(mddev->bitmap_file);
5034 			fput(mddev->bitmap_file);
5035 		}
5036 		mddev->bitmap_file = NULL;
5037 	}
5038 
5039 	return err;
5040 }
5041 
5042 /*
5043  * set_array_info is used two different ways
5044  * The original usage is when creating a new array.
5045  * In this usage, raid_disks is > 0 and it together with
5046  *  level, size, not_persistent,layout,chunksize determine the
5047  *  shape of the array.
5048  *  This will always create an array with a type-0.90.0 superblock.
5049  * The newer usage is when assembling an array.
5050  *  In this case raid_disks will be 0, and the major_version field is
5051  *  use to determine which style super-blocks are to be found on the devices.
5052  *  The minor and patch _version numbers are also kept incase the
5053  *  super_block handler wishes to interpret them.
5054  */
5055 static int set_array_info(mddev_t * mddev, mdu_array_info_t *info)
5056 {
5057 
5058 	if (info->raid_disks == 0) {
5059 		/* just setting version number for superblock loading */
5060 		if (info->major_version < 0 ||
5061 		    info->major_version >= ARRAY_SIZE(super_types) ||
5062 		    super_types[info->major_version].name == NULL) {
5063 			/* maybe try to auto-load a module? */
5064 			printk(KERN_INFO
5065 				"md: superblock version %d not known\n",
5066 				info->major_version);
5067 			return -EINVAL;
5068 		}
5069 		mddev->major_version = info->major_version;
5070 		mddev->minor_version = info->minor_version;
5071 		mddev->patch_version = info->patch_version;
5072 		mddev->persistent = !info->not_persistent;
5073 		return 0;
5074 	}
5075 	mddev->major_version = MD_MAJOR_VERSION;
5076 	mddev->minor_version = MD_MINOR_VERSION;
5077 	mddev->patch_version = MD_PATCHLEVEL_VERSION;
5078 	mddev->ctime         = get_seconds();
5079 
5080 	mddev->level         = info->level;
5081 	mddev->clevel[0]     = 0;
5082 	mddev->dev_sectors   = 2 * (sector_t)info->size;
5083 	mddev->raid_disks    = info->raid_disks;
5084 	/* don't set md_minor, it is determined by which /dev/md* was
5085 	 * openned
5086 	 */
5087 	if (info->state & (1<<MD_SB_CLEAN))
5088 		mddev->recovery_cp = MaxSector;
5089 	else
5090 		mddev->recovery_cp = 0;
5091 	mddev->persistent    = ! info->not_persistent;
5092 	mddev->external	     = 0;
5093 
5094 	mddev->layout        = info->layout;
5095 	mddev->chunk_sectors = info->chunk_size >> 9;
5096 
5097 	mddev->max_disks     = MD_SB_DISKS;
5098 
5099 	if (mddev->persistent)
5100 		mddev->flags         = 0;
5101 	set_bit(MD_CHANGE_DEVS, &mddev->flags);
5102 
5103 	mddev->default_bitmap_offset = MD_SB_BYTES >> 9;
5104 	mddev->bitmap_offset = 0;
5105 
5106 	mddev->reshape_position = MaxSector;
5107 
5108 	/*
5109 	 * Generate a 128 bit UUID
5110 	 */
5111 	get_random_bytes(mddev->uuid, 16);
5112 
5113 	mddev->new_level = mddev->level;
5114 	mddev->new_chunk_sectors = mddev->chunk_sectors;
5115 	mddev->new_layout = mddev->layout;
5116 	mddev->delta_disks = 0;
5117 
5118 	return 0;
5119 }
5120 
5121 void md_set_array_sectors(mddev_t *mddev, sector_t array_sectors)
5122 {
5123 	WARN(!mddev_is_locked(mddev), "%s: unlocked mddev!\n", __func__);
5124 
5125 	if (mddev->external_size)
5126 		return;
5127 
5128 	mddev->array_sectors = array_sectors;
5129 }
5130 EXPORT_SYMBOL(md_set_array_sectors);
5131 
5132 static int update_size(mddev_t *mddev, sector_t num_sectors)
5133 {
5134 	mdk_rdev_t *rdev;
5135 	int rv;
5136 	int fit = (num_sectors == 0);
5137 
5138 	if (mddev->pers->resize == NULL)
5139 		return -EINVAL;
5140 	/* The "num_sectors" is the number of sectors of each device that
5141 	 * is used.  This can only make sense for arrays with redundancy.
5142 	 * linear and raid0 always use whatever space is available. We can only
5143 	 * consider changing this number if no resync or reconstruction is
5144 	 * happening, and if the new size is acceptable. It must fit before the
5145 	 * sb_start or, if that is <data_offset, it must fit before the size
5146 	 * of each device.  If num_sectors is zero, we find the largest size
5147 	 * that fits.
5148 
5149 	 */
5150 	if (mddev->sync_thread)
5151 		return -EBUSY;
5152 	if (mddev->bitmap)
5153 		/* Sorry, cannot grow a bitmap yet, just remove it,
5154 		 * grow, and re-add.
5155 		 */
5156 		return -EBUSY;
5157 	list_for_each_entry(rdev, &mddev->disks, same_set) {
5158 		sector_t avail = rdev->sectors;
5159 
5160 		if (fit && (num_sectors == 0 || num_sectors > avail))
5161 			num_sectors = avail;
5162 		if (avail < num_sectors)
5163 			return -ENOSPC;
5164 	}
5165 	rv = mddev->pers->resize(mddev, num_sectors);
5166 	if (!rv)
5167 		revalidate_disk(mddev->gendisk);
5168 	return rv;
5169 }
5170 
5171 static int update_raid_disks(mddev_t *mddev, int raid_disks)
5172 {
5173 	int rv;
5174 	/* change the number of raid disks */
5175 	if (mddev->pers->check_reshape == NULL)
5176 		return -EINVAL;
5177 	if (raid_disks <= 0 ||
5178 	    raid_disks >= mddev->max_disks)
5179 		return -EINVAL;
5180 	if (mddev->sync_thread || mddev->reshape_position != MaxSector)
5181 		return -EBUSY;
5182 	mddev->delta_disks = raid_disks - mddev->raid_disks;
5183 
5184 	rv = mddev->pers->check_reshape(mddev);
5185 	return rv;
5186 }
5187 
5188 
5189 /*
5190  * update_array_info is used to change the configuration of an
5191  * on-line array.
5192  * The version, ctime,level,size,raid_disks,not_persistent, layout,chunk_size
5193  * fields in the info are checked against the array.
5194  * Any differences that cannot be handled will cause an error.
5195  * Normally, only one change can be managed at a time.
5196  */
5197 static int update_array_info(mddev_t *mddev, mdu_array_info_t *info)
5198 {
5199 	int rv = 0;
5200 	int cnt = 0;
5201 	int state = 0;
5202 
5203 	/* calculate expected state,ignoring low bits */
5204 	if (mddev->bitmap && mddev->bitmap_offset)
5205 		state |= (1 << MD_SB_BITMAP_PRESENT);
5206 
5207 	if (mddev->major_version != info->major_version ||
5208 	    mddev->minor_version != info->minor_version ||
5209 /*	    mddev->patch_version != info->patch_version || */
5210 	    mddev->ctime         != info->ctime         ||
5211 	    mddev->level         != info->level         ||
5212 /*	    mddev->layout        != info->layout        || */
5213 	    !mddev->persistent	 != info->not_persistent||
5214 	    mddev->chunk_sectors != info->chunk_size >> 9 ||
5215 	    /* ignore bottom 8 bits of state, and allow SB_BITMAP_PRESENT to change */
5216 	    ((state^info->state) & 0xfffffe00)
5217 		)
5218 		return -EINVAL;
5219 	/* Check there is only one change */
5220 	if (info->size >= 0 && mddev->dev_sectors / 2 != info->size)
5221 		cnt++;
5222 	if (mddev->raid_disks != info->raid_disks)
5223 		cnt++;
5224 	if (mddev->layout != info->layout)
5225 		cnt++;
5226 	if ((state ^ info->state) & (1<<MD_SB_BITMAP_PRESENT))
5227 		cnt++;
5228 	if (cnt == 0)
5229 		return 0;
5230 	if (cnt > 1)
5231 		return -EINVAL;
5232 
5233 	if (mddev->layout != info->layout) {
5234 		/* Change layout
5235 		 * we don't need to do anything at the md level, the
5236 		 * personality will take care of it all.
5237 		 */
5238 		if (mddev->pers->check_reshape == NULL)
5239 			return -EINVAL;
5240 		else {
5241 			mddev->new_layout = info->layout;
5242 			rv = mddev->pers->check_reshape(mddev);
5243 			if (rv)
5244 				mddev->new_layout = mddev->layout;
5245 			return rv;
5246 		}
5247 	}
5248 	if (info->size >= 0 && mddev->dev_sectors / 2 != info->size)
5249 		rv = update_size(mddev, (sector_t)info->size * 2);
5250 
5251 	if (mddev->raid_disks    != info->raid_disks)
5252 		rv = update_raid_disks(mddev, info->raid_disks);
5253 
5254 	if ((state ^ info->state) & (1<<MD_SB_BITMAP_PRESENT)) {
5255 		if (mddev->pers->quiesce == NULL)
5256 			return -EINVAL;
5257 		if (mddev->recovery || mddev->sync_thread)
5258 			return -EBUSY;
5259 		if (info->state & (1<<MD_SB_BITMAP_PRESENT)) {
5260 			/* add the bitmap */
5261 			if (mddev->bitmap)
5262 				return -EEXIST;
5263 			if (mddev->default_bitmap_offset == 0)
5264 				return -EINVAL;
5265 			mddev->bitmap_offset = mddev->default_bitmap_offset;
5266 			mddev->pers->quiesce(mddev, 1);
5267 			rv = bitmap_create(mddev);
5268 			if (rv)
5269 				bitmap_destroy(mddev);
5270 			mddev->pers->quiesce(mddev, 0);
5271 		} else {
5272 			/* remove the bitmap */
5273 			if (!mddev->bitmap)
5274 				return -ENOENT;
5275 			if (mddev->bitmap->file)
5276 				return -EINVAL;
5277 			mddev->pers->quiesce(mddev, 1);
5278 			bitmap_destroy(mddev);
5279 			mddev->pers->quiesce(mddev, 0);
5280 			mddev->bitmap_offset = 0;
5281 		}
5282 	}
5283 	md_update_sb(mddev, 1);
5284 	return rv;
5285 }
5286 
5287 static int set_disk_faulty(mddev_t *mddev, dev_t dev)
5288 {
5289 	mdk_rdev_t *rdev;
5290 
5291 	if (mddev->pers == NULL)
5292 		return -ENODEV;
5293 
5294 	rdev = find_rdev(mddev, dev);
5295 	if (!rdev)
5296 		return -ENODEV;
5297 
5298 	md_error(mddev, rdev);
5299 	return 0;
5300 }
5301 
5302 /*
5303  * We have a problem here : there is no easy way to give a CHS
5304  * virtual geometry. We currently pretend that we have a 2 heads
5305  * 4 sectors (with a BIG number of cylinders...). This drives
5306  * dosfs just mad... ;-)
5307  */
5308 static int md_getgeo(struct block_device *bdev, struct hd_geometry *geo)
5309 {
5310 	mddev_t *mddev = bdev->bd_disk->private_data;
5311 
5312 	geo->heads = 2;
5313 	geo->sectors = 4;
5314 	geo->cylinders = get_capacity(mddev->gendisk) / 8;
5315 	return 0;
5316 }
5317 
5318 static int md_ioctl(struct block_device *bdev, fmode_t mode,
5319 			unsigned int cmd, unsigned long arg)
5320 {
5321 	int err = 0;
5322 	void __user *argp = (void __user *)arg;
5323 	mddev_t *mddev = NULL;
5324 
5325 	if (!capable(CAP_SYS_ADMIN))
5326 		return -EACCES;
5327 
5328 	/*
5329 	 * Commands dealing with the RAID driver but not any
5330 	 * particular array:
5331 	 */
5332 	switch (cmd)
5333 	{
5334 		case RAID_VERSION:
5335 			err = get_version(argp);
5336 			goto done;
5337 
5338 		case PRINT_RAID_DEBUG:
5339 			err = 0;
5340 			md_print_devices();
5341 			goto done;
5342 
5343 #ifndef MODULE
5344 		case RAID_AUTORUN:
5345 			err = 0;
5346 			autostart_arrays(arg);
5347 			goto done;
5348 #endif
5349 		default:;
5350 	}
5351 
5352 	/*
5353 	 * Commands creating/starting a new array:
5354 	 */
5355 
5356 	mddev = bdev->bd_disk->private_data;
5357 
5358 	if (!mddev) {
5359 		BUG();
5360 		goto abort;
5361 	}
5362 
5363 	err = mddev_lock(mddev);
5364 	if (err) {
5365 		printk(KERN_INFO
5366 			"md: ioctl lock interrupted, reason %d, cmd %d\n",
5367 			err, cmd);
5368 		goto abort;
5369 	}
5370 
5371 	switch (cmd)
5372 	{
5373 		case SET_ARRAY_INFO:
5374 			{
5375 				mdu_array_info_t info;
5376 				if (!arg)
5377 					memset(&info, 0, sizeof(info));
5378 				else if (copy_from_user(&info, argp, sizeof(info))) {
5379 					err = -EFAULT;
5380 					goto abort_unlock;
5381 				}
5382 				if (mddev->pers) {
5383 					err = update_array_info(mddev, &info);
5384 					if (err) {
5385 						printk(KERN_WARNING "md: couldn't update"
5386 						       " array info. %d\n", err);
5387 						goto abort_unlock;
5388 					}
5389 					goto done_unlock;
5390 				}
5391 				if (!list_empty(&mddev->disks)) {
5392 					printk(KERN_WARNING
5393 					       "md: array %s already has disks!\n",
5394 					       mdname(mddev));
5395 					err = -EBUSY;
5396 					goto abort_unlock;
5397 				}
5398 				if (mddev->raid_disks) {
5399 					printk(KERN_WARNING
5400 					       "md: array %s already initialised!\n",
5401 					       mdname(mddev));
5402 					err = -EBUSY;
5403 					goto abort_unlock;
5404 				}
5405 				err = set_array_info(mddev, &info);
5406 				if (err) {
5407 					printk(KERN_WARNING "md: couldn't set"
5408 					       " array info. %d\n", err);
5409 					goto abort_unlock;
5410 				}
5411 			}
5412 			goto done_unlock;
5413 
5414 		default:;
5415 	}
5416 
5417 	/*
5418 	 * Commands querying/configuring an existing array:
5419 	 */
5420 	/* if we are not initialised yet, only ADD_NEW_DISK, STOP_ARRAY,
5421 	 * RUN_ARRAY, and GET_ and SET_BITMAP_FILE are allowed */
5422 	if ((!mddev->raid_disks && !mddev->external)
5423 	    && cmd != ADD_NEW_DISK && cmd != STOP_ARRAY
5424 	    && cmd != RUN_ARRAY && cmd != SET_BITMAP_FILE
5425 	    && cmd != GET_BITMAP_FILE) {
5426 		err = -ENODEV;
5427 		goto abort_unlock;
5428 	}
5429 
5430 	/*
5431 	 * Commands even a read-only array can execute:
5432 	 */
5433 	switch (cmd)
5434 	{
5435 		case GET_ARRAY_INFO:
5436 			err = get_array_info(mddev, argp);
5437 			goto done_unlock;
5438 
5439 		case GET_BITMAP_FILE:
5440 			err = get_bitmap_file(mddev, argp);
5441 			goto done_unlock;
5442 
5443 		case GET_DISK_INFO:
5444 			err = get_disk_info(mddev, argp);
5445 			goto done_unlock;
5446 
5447 		case RESTART_ARRAY_RW:
5448 			err = restart_array(mddev);
5449 			goto done_unlock;
5450 
5451 		case STOP_ARRAY:
5452 			err = do_md_stop(mddev, 0, 1);
5453 			goto done_unlock;
5454 
5455 		case STOP_ARRAY_RO:
5456 			err = do_md_stop(mddev, 1, 1);
5457 			goto done_unlock;
5458 
5459 	}
5460 
5461 	/*
5462 	 * The remaining ioctls are changing the state of the
5463 	 * superblock, so we do not allow them on read-only arrays.
5464 	 * However non-MD ioctls (e.g. get-size) will still come through
5465 	 * here and hit the 'default' below, so only disallow
5466 	 * 'md' ioctls, and switch to rw mode if started auto-readonly.
5467 	 */
5468 	if (_IOC_TYPE(cmd) == MD_MAJOR && mddev->ro && mddev->pers) {
5469 		if (mddev->ro == 2) {
5470 			mddev->ro = 0;
5471 			sysfs_notify_dirent(mddev->sysfs_state);
5472 			set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
5473 			md_wakeup_thread(mddev->thread);
5474 		} else {
5475 			err = -EROFS;
5476 			goto abort_unlock;
5477 		}
5478 	}
5479 
5480 	switch (cmd)
5481 	{
5482 		case ADD_NEW_DISK:
5483 		{
5484 			mdu_disk_info_t info;
5485 			if (copy_from_user(&info, argp, sizeof(info)))
5486 				err = -EFAULT;
5487 			else
5488 				err = add_new_disk(mddev, &info);
5489 			goto done_unlock;
5490 		}
5491 
5492 		case HOT_REMOVE_DISK:
5493 			err = hot_remove_disk(mddev, new_decode_dev(arg));
5494 			goto done_unlock;
5495 
5496 		case HOT_ADD_DISK:
5497 			err = hot_add_disk(mddev, new_decode_dev(arg));
5498 			goto done_unlock;
5499 
5500 		case SET_DISK_FAULTY:
5501 			err = set_disk_faulty(mddev, new_decode_dev(arg));
5502 			goto done_unlock;
5503 
5504 		case RUN_ARRAY:
5505 			err = do_md_run(mddev);
5506 			goto done_unlock;
5507 
5508 		case SET_BITMAP_FILE:
5509 			err = set_bitmap_file(mddev, (int)arg);
5510 			goto done_unlock;
5511 
5512 		default:
5513 			err = -EINVAL;
5514 			goto abort_unlock;
5515 	}
5516 
5517 done_unlock:
5518 abort_unlock:
5519 	if (mddev->hold_active == UNTIL_IOCTL &&
5520 	    err != -EINVAL)
5521 		mddev->hold_active = 0;
5522 	mddev_unlock(mddev);
5523 
5524 	return err;
5525 done:
5526 	if (err)
5527 		MD_BUG();
5528 abort:
5529 	return err;
5530 }
5531 
5532 static int md_open(struct block_device *bdev, fmode_t mode)
5533 {
5534 	/*
5535 	 * Succeed if we can lock the mddev, which confirms that
5536 	 * it isn't being stopped right now.
5537 	 */
5538 	mddev_t *mddev = mddev_find(bdev->bd_dev);
5539 	int err;
5540 
5541 	if (mddev->gendisk != bdev->bd_disk) {
5542 		/* we are racing with mddev_put which is discarding this
5543 		 * bd_disk.
5544 		 */
5545 		mddev_put(mddev);
5546 		/* Wait until bdev->bd_disk is definitely gone */
5547 		flush_scheduled_work();
5548 		/* Then retry the open from the top */
5549 		return -ERESTARTSYS;
5550 	}
5551 	BUG_ON(mddev != bdev->bd_disk->private_data);
5552 
5553 	if ((err = mutex_lock_interruptible(&mddev->open_mutex)))
5554 		goto out;
5555 
5556 	err = 0;
5557 	atomic_inc(&mddev->openers);
5558 	mutex_unlock(&mddev->open_mutex);
5559 
5560 	check_disk_change(bdev);
5561  out:
5562 	return err;
5563 }
5564 
5565 static int md_release(struct gendisk *disk, fmode_t mode)
5566 {
5567  	mddev_t *mddev = disk->private_data;
5568 
5569 	BUG_ON(!mddev);
5570 	atomic_dec(&mddev->openers);
5571 	mddev_put(mddev);
5572 
5573 	return 0;
5574 }
5575 
5576 static int md_media_changed(struct gendisk *disk)
5577 {
5578 	mddev_t *mddev = disk->private_data;
5579 
5580 	return mddev->changed;
5581 }
5582 
5583 static int md_revalidate(struct gendisk *disk)
5584 {
5585 	mddev_t *mddev = disk->private_data;
5586 
5587 	mddev->changed = 0;
5588 	return 0;
5589 }
5590 static const struct block_device_operations md_fops =
5591 {
5592 	.owner		= THIS_MODULE,
5593 	.open		= md_open,
5594 	.release	= md_release,
5595 	.ioctl		= md_ioctl,
5596 	.getgeo		= md_getgeo,
5597 	.media_changed	= md_media_changed,
5598 	.revalidate_disk= md_revalidate,
5599 };
5600 
5601 static int md_thread(void * arg)
5602 {
5603 	mdk_thread_t *thread = arg;
5604 
5605 	/*
5606 	 * md_thread is a 'system-thread', it's priority should be very
5607 	 * high. We avoid resource deadlocks individually in each
5608 	 * raid personality. (RAID5 does preallocation) We also use RR and
5609 	 * the very same RT priority as kswapd, thus we will never get
5610 	 * into a priority inversion deadlock.
5611 	 *
5612 	 * we definitely have to have equal or higher priority than
5613 	 * bdflush, otherwise bdflush will deadlock if there are too
5614 	 * many dirty RAID5 blocks.
5615 	 */
5616 
5617 	allow_signal(SIGKILL);
5618 	while (!kthread_should_stop()) {
5619 
5620 		/* We need to wait INTERRUPTIBLE so that
5621 		 * we don't add to the load-average.
5622 		 * That means we need to be sure no signals are
5623 		 * pending
5624 		 */
5625 		if (signal_pending(current))
5626 			flush_signals(current);
5627 
5628 		wait_event_interruptible_timeout
5629 			(thread->wqueue,
5630 			 test_bit(THREAD_WAKEUP, &thread->flags)
5631 			 || kthread_should_stop(),
5632 			 thread->timeout);
5633 
5634 		clear_bit(THREAD_WAKEUP, &thread->flags);
5635 
5636 		thread->run(thread->mddev);
5637 	}
5638 
5639 	return 0;
5640 }
5641 
5642 void md_wakeup_thread(mdk_thread_t *thread)
5643 {
5644 	if (thread) {
5645 		dprintk("md: waking up MD thread %s.\n", thread->tsk->comm);
5646 		set_bit(THREAD_WAKEUP, &thread->flags);
5647 		wake_up(&thread->wqueue);
5648 	}
5649 }
5650 
5651 mdk_thread_t *md_register_thread(void (*run) (mddev_t *), mddev_t *mddev,
5652 				 const char *name)
5653 {
5654 	mdk_thread_t *thread;
5655 
5656 	thread = kzalloc(sizeof(mdk_thread_t), GFP_KERNEL);
5657 	if (!thread)
5658 		return NULL;
5659 
5660 	init_waitqueue_head(&thread->wqueue);
5661 
5662 	thread->run = run;
5663 	thread->mddev = mddev;
5664 	thread->timeout = MAX_SCHEDULE_TIMEOUT;
5665 	thread->tsk = kthread_run(md_thread, thread,
5666 				  "%s_%s",
5667 				  mdname(thread->mddev),
5668 				  name ?: mddev->pers->name);
5669 	if (IS_ERR(thread->tsk)) {
5670 		kfree(thread);
5671 		return NULL;
5672 	}
5673 	return thread;
5674 }
5675 
5676 void md_unregister_thread(mdk_thread_t *thread)
5677 {
5678 	if (!thread)
5679 		return;
5680 	dprintk("interrupting MD-thread pid %d\n", task_pid_nr(thread->tsk));
5681 
5682 	kthread_stop(thread->tsk);
5683 	kfree(thread);
5684 }
5685 
5686 void md_error(mddev_t *mddev, mdk_rdev_t *rdev)
5687 {
5688 	if (!mddev) {
5689 		MD_BUG();
5690 		return;
5691 	}
5692 
5693 	if (!rdev || test_bit(Faulty, &rdev->flags))
5694 		return;
5695 
5696 	if (mddev->external)
5697 		set_bit(Blocked, &rdev->flags);
5698 /*
5699 	dprintk("md_error dev:%s, rdev:(%d:%d), (caller: %p,%p,%p,%p).\n",
5700 		mdname(mddev),
5701 		MAJOR(rdev->bdev->bd_dev), MINOR(rdev->bdev->bd_dev),
5702 		__builtin_return_address(0),__builtin_return_address(1),
5703 		__builtin_return_address(2),__builtin_return_address(3));
5704 */
5705 	if (!mddev->pers)
5706 		return;
5707 	if (!mddev->pers->error_handler)
5708 		return;
5709 	mddev->pers->error_handler(mddev,rdev);
5710 	if (mddev->degraded)
5711 		set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
5712 	set_bit(StateChanged, &rdev->flags);
5713 	set_bit(MD_RECOVERY_INTR, &mddev->recovery);
5714 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
5715 	md_wakeup_thread(mddev->thread);
5716 	md_new_event_inintr(mddev);
5717 }
5718 
5719 /* seq_file implementation /proc/mdstat */
5720 
5721 static void status_unused(struct seq_file *seq)
5722 {
5723 	int i = 0;
5724 	mdk_rdev_t *rdev;
5725 
5726 	seq_printf(seq, "unused devices: ");
5727 
5728 	list_for_each_entry(rdev, &pending_raid_disks, same_set) {
5729 		char b[BDEVNAME_SIZE];
5730 		i++;
5731 		seq_printf(seq, "%s ",
5732 			      bdevname(rdev->bdev,b));
5733 	}
5734 	if (!i)
5735 		seq_printf(seq, "<none>");
5736 
5737 	seq_printf(seq, "\n");
5738 }
5739 
5740 
5741 static void status_resync(struct seq_file *seq, mddev_t * mddev)
5742 {
5743 	sector_t max_sectors, resync, res;
5744 	unsigned long dt, db;
5745 	sector_t rt;
5746 	int scale;
5747 	unsigned int per_milli;
5748 
5749 	resync = mddev->curr_resync - atomic_read(&mddev->recovery_active);
5750 
5751 	if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery))
5752 		max_sectors = mddev->resync_max_sectors;
5753 	else
5754 		max_sectors = mddev->dev_sectors;
5755 
5756 	/*
5757 	 * Should not happen.
5758 	 */
5759 	if (!max_sectors) {
5760 		MD_BUG();
5761 		return;
5762 	}
5763 	/* Pick 'scale' such that (resync>>scale)*1000 will fit
5764 	 * in a sector_t, and (max_sectors>>scale) will fit in a
5765 	 * u32, as those are the requirements for sector_div.
5766 	 * Thus 'scale' must be at least 10
5767 	 */
5768 	scale = 10;
5769 	if (sizeof(sector_t) > sizeof(unsigned long)) {
5770 		while ( max_sectors/2 > (1ULL<<(scale+32)))
5771 			scale++;
5772 	}
5773 	res = (resync>>scale)*1000;
5774 	sector_div(res, (u32)((max_sectors>>scale)+1));
5775 
5776 	per_milli = res;
5777 	{
5778 		int i, x = per_milli/50, y = 20-x;
5779 		seq_printf(seq, "[");
5780 		for (i = 0; i < x; i++)
5781 			seq_printf(seq, "=");
5782 		seq_printf(seq, ">");
5783 		for (i = 0; i < y; i++)
5784 			seq_printf(seq, ".");
5785 		seq_printf(seq, "] ");
5786 	}
5787 	seq_printf(seq, " %s =%3u.%u%% (%llu/%llu)",
5788 		   (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)?
5789 		    "reshape" :
5790 		    (test_bit(MD_RECOVERY_CHECK, &mddev->recovery)?
5791 		     "check" :
5792 		     (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) ?
5793 		      "resync" : "recovery"))),
5794 		   per_milli/10, per_milli % 10,
5795 		   (unsigned long long) resync/2,
5796 		   (unsigned long long) max_sectors/2);
5797 
5798 	/*
5799 	 * dt: time from mark until now
5800 	 * db: blocks written from mark until now
5801 	 * rt: remaining time
5802 	 *
5803 	 * rt is a sector_t, so could be 32bit or 64bit.
5804 	 * So we divide before multiply in case it is 32bit and close
5805 	 * to the limit.
5806 	 * We scale the divisor (db) by 32 to avoid loosing precision
5807 	 * near the end of resync when the number of remaining sectors
5808 	 * is close to 'db'.
5809 	 * We then divide rt by 32 after multiplying by db to compensate.
5810 	 * The '+1' avoids division by zero if db is very small.
5811 	 */
5812 	dt = ((jiffies - mddev->resync_mark) / HZ);
5813 	if (!dt) dt++;
5814 	db = (mddev->curr_mark_cnt - atomic_read(&mddev->recovery_active))
5815 		- mddev->resync_mark_cnt;
5816 
5817 	rt = max_sectors - resync;    /* number of remaining sectors */
5818 	sector_div(rt, db/32+1);
5819 	rt *= dt;
5820 	rt >>= 5;
5821 
5822 	seq_printf(seq, " finish=%lu.%lumin", (unsigned long)rt / 60,
5823 		   ((unsigned long)rt % 60)/6);
5824 
5825 	seq_printf(seq, " speed=%ldK/sec", db/2/dt);
5826 }
5827 
5828 static void *md_seq_start(struct seq_file *seq, loff_t *pos)
5829 {
5830 	struct list_head *tmp;
5831 	loff_t l = *pos;
5832 	mddev_t *mddev;
5833 
5834 	if (l >= 0x10000)
5835 		return NULL;
5836 	if (!l--)
5837 		/* header */
5838 		return (void*)1;
5839 
5840 	spin_lock(&all_mddevs_lock);
5841 	list_for_each(tmp,&all_mddevs)
5842 		if (!l--) {
5843 			mddev = list_entry(tmp, mddev_t, all_mddevs);
5844 			mddev_get(mddev);
5845 			spin_unlock(&all_mddevs_lock);
5846 			return mddev;
5847 		}
5848 	spin_unlock(&all_mddevs_lock);
5849 	if (!l--)
5850 		return (void*)2;/* tail */
5851 	return NULL;
5852 }
5853 
5854 static void *md_seq_next(struct seq_file *seq, void *v, loff_t *pos)
5855 {
5856 	struct list_head *tmp;
5857 	mddev_t *next_mddev, *mddev = v;
5858 
5859 	++*pos;
5860 	if (v == (void*)2)
5861 		return NULL;
5862 
5863 	spin_lock(&all_mddevs_lock);
5864 	if (v == (void*)1)
5865 		tmp = all_mddevs.next;
5866 	else
5867 		tmp = mddev->all_mddevs.next;
5868 	if (tmp != &all_mddevs)
5869 		next_mddev = mddev_get(list_entry(tmp,mddev_t,all_mddevs));
5870 	else {
5871 		next_mddev = (void*)2;
5872 		*pos = 0x10000;
5873 	}
5874 	spin_unlock(&all_mddevs_lock);
5875 
5876 	if (v != (void*)1)
5877 		mddev_put(mddev);
5878 	return next_mddev;
5879 
5880 }
5881 
5882 static void md_seq_stop(struct seq_file *seq, void *v)
5883 {
5884 	mddev_t *mddev = v;
5885 
5886 	if (mddev && v != (void*)1 && v != (void*)2)
5887 		mddev_put(mddev);
5888 }
5889 
5890 struct mdstat_info {
5891 	int event;
5892 };
5893 
5894 static int md_seq_show(struct seq_file *seq, void *v)
5895 {
5896 	mddev_t *mddev = v;
5897 	sector_t sectors;
5898 	mdk_rdev_t *rdev;
5899 	struct mdstat_info *mi = seq->private;
5900 	struct bitmap *bitmap;
5901 
5902 	if (v == (void*)1) {
5903 		struct mdk_personality *pers;
5904 		seq_printf(seq, "Personalities : ");
5905 		spin_lock(&pers_lock);
5906 		list_for_each_entry(pers, &pers_list, list)
5907 			seq_printf(seq, "[%s] ", pers->name);
5908 
5909 		spin_unlock(&pers_lock);
5910 		seq_printf(seq, "\n");
5911 		mi->event = atomic_read(&md_event_count);
5912 		return 0;
5913 	}
5914 	if (v == (void*)2) {
5915 		status_unused(seq);
5916 		return 0;
5917 	}
5918 
5919 	if (mddev_lock(mddev) < 0)
5920 		return -EINTR;
5921 
5922 	if (mddev->pers || mddev->raid_disks || !list_empty(&mddev->disks)) {
5923 		seq_printf(seq, "%s : %sactive", mdname(mddev),
5924 						mddev->pers ? "" : "in");
5925 		if (mddev->pers) {
5926 			if (mddev->ro==1)
5927 				seq_printf(seq, " (read-only)");
5928 			if (mddev->ro==2)
5929 				seq_printf(seq, " (auto-read-only)");
5930 			seq_printf(seq, " %s", mddev->pers->name);
5931 		}
5932 
5933 		sectors = 0;
5934 		list_for_each_entry(rdev, &mddev->disks, same_set) {
5935 			char b[BDEVNAME_SIZE];
5936 			seq_printf(seq, " %s[%d]",
5937 				bdevname(rdev->bdev,b), rdev->desc_nr);
5938 			if (test_bit(WriteMostly, &rdev->flags))
5939 				seq_printf(seq, "(W)");
5940 			if (test_bit(Faulty, &rdev->flags)) {
5941 				seq_printf(seq, "(F)");
5942 				continue;
5943 			} else if (rdev->raid_disk < 0)
5944 				seq_printf(seq, "(S)"); /* spare */
5945 			sectors += rdev->sectors;
5946 		}
5947 
5948 		if (!list_empty(&mddev->disks)) {
5949 			if (mddev->pers)
5950 				seq_printf(seq, "\n      %llu blocks",
5951 					   (unsigned long long)
5952 					   mddev->array_sectors / 2);
5953 			else
5954 				seq_printf(seq, "\n      %llu blocks",
5955 					   (unsigned long long)sectors / 2);
5956 		}
5957 		if (mddev->persistent) {
5958 			if (mddev->major_version != 0 ||
5959 			    mddev->minor_version != 90) {
5960 				seq_printf(seq," super %d.%d",
5961 					   mddev->major_version,
5962 					   mddev->minor_version);
5963 			}
5964 		} else if (mddev->external)
5965 			seq_printf(seq, " super external:%s",
5966 				   mddev->metadata_type);
5967 		else
5968 			seq_printf(seq, " super non-persistent");
5969 
5970 		if (mddev->pers) {
5971 			mddev->pers->status(seq, mddev);
5972 	 		seq_printf(seq, "\n      ");
5973 			if (mddev->pers->sync_request) {
5974 				if (mddev->curr_resync > 2) {
5975 					status_resync(seq, mddev);
5976 					seq_printf(seq, "\n      ");
5977 				} else if (mddev->curr_resync == 1 || mddev->curr_resync == 2)
5978 					seq_printf(seq, "\tresync=DELAYED\n      ");
5979 				else if (mddev->recovery_cp < MaxSector)
5980 					seq_printf(seq, "\tresync=PENDING\n      ");
5981 			}
5982 		} else
5983 			seq_printf(seq, "\n       ");
5984 
5985 		if ((bitmap = mddev->bitmap)) {
5986 			unsigned long chunk_kb;
5987 			unsigned long flags;
5988 			spin_lock_irqsave(&bitmap->lock, flags);
5989 			chunk_kb = bitmap->chunksize >> 10;
5990 			seq_printf(seq, "bitmap: %lu/%lu pages [%luKB], "
5991 				"%lu%s chunk",
5992 				bitmap->pages - bitmap->missing_pages,
5993 				bitmap->pages,
5994 				(bitmap->pages - bitmap->missing_pages)
5995 					<< (PAGE_SHIFT - 10),
5996 				chunk_kb ? chunk_kb : bitmap->chunksize,
5997 				chunk_kb ? "KB" : "B");
5998 			if (bitmap->file) {
5999 				seq_printf(seq, ", file: ");
6000 				seq_path(seq, &bitmap->file->f_path, " \t\n");
6001 			}
6002 
6003 			seq_printf(seq, "\n");
6004 			spin_unlock_irqrestore(&bitmap->lock, flags);
6005 		}
6006 
6007 		seq_printf(seq, "\n");
6008 	}
6009 	mddev_unlock(mddev);
6010 
6011 	return 0;
6012 }
6013 
6014 static const struct seq_operations md_seq_ops = {
6015 	.start  = md_seq_start,
6016 	.next   = md_seq_next,
6017 	.stop   = md_seq_stop,
6018 	.show   = md_seq_show,
6019 };
6020 
6021 static int md_seq_open(struct inode *inode, struct file *file)
6022 {
6023 	int error;
6024 	struct mdstat_info *mi = kmalloc(sizeof(*mi), GFP_KERNEL);
6025 	if (mi == NULL)
6026 		return -ENOMEM;
6027 
6028 	error = seq_open(file, &md_seq_ops);
6029 	if (error)
6030 		kfree(mi);
6031 	else {
6032 		struct seq_file *p = file->private_data;
6033 		p->private = mi;
6034 		mi->event = atomic_read(&md_event_count);
6035 	}
6036 	return error;
6037 }
6038 
6039 static unsigned int mdstat_poll(struct file *filp, poll_table *wait)
6040 {
6041 	struct seq_file *m = filp->private_data;
6042 	struct mdstat_info *mi = m->private;
6043 	int mask;
6044 
6045 	poll_wait(filp, &md_event_waiters, wait);
6046 
6047 	/* always allow read */
6048 	mask = POLLIN | POLLRDNORM;
6049 
6050 	if (mi->event != atomic_read(&md_event_count))
6051 		mask |= POLLERR | POLLPRI;
6052 	return mask;
6053 }
6054 
6055 static const struct file_operations md_seq_fops = {
6056 	.owner		= THIS_MODULE,
6057 	.open           = md_seq_open,
6058 	.read           = seq_read,
6059 	.llseek         = seq_lseek,
6060 	.release	= seq_release_private,
6061 	.poll		= mdstat_poll,
6062 };
6063 
6064 int register_md_personality(struct mdk_personality *p)
6065 {
6066 	spin_lock(&pers_lock);
6067 	list_add_tail(&p->list, &pers_list);
6068 	printk(KERN_INFO "md: %s personality registered for level %d\n", p->name, p->level);
6069 	spin_unlock(&pers_lock);
6070 	return 0;
6071 }
6072 
6073 int unregister_md_personality(struct mdk_personality *p)
6074 {
6075 	printk(KERN_INFO "md: %s personality unregistered\n", p->name);
6076 	spin_lock(&pers_lock);
6077 	list_del_init(&p->list);
6078 	spin_unlock(&pers_lock);
6079 	return 0;
6080 }
6081 
6082 static int is_mddev_idle(mddev_t *mddev, int init)
6083 {
6084 	mdk_rdev_t * rdev;
6085 	int idle;
6086 	int curr_events;
6087 
6088 	idle = 1;
6089 	rcu_read_lock();
6090 	rdev_for_each_rcu(rdev, mddev) {
6091 		struct gendisk *disk = rdev->bdev->bd_contains->bd_disk;
6092 		curr_events = (int)part_stat_read(&disk->part0, sectors[0]) +
6093 			      (int)part_stat_read(&disk->part0, sectors[1]) -
6094 			      atomic_read(&disk->sync_io);
6095 		/* sync IO will cause sync_io to increase before the disk_stats
6096 		 * as sync_io is counted when a request starts, and
6097 		 * disk_stats is counted when it completes.
6098 		 * So resync activity will cause curr_events to be smaller than
6099 		 * when there was no such activity.
6100 		 * non-sync IO will cause disk_stat to increase without
6101 		 * increasing sync_io so curr_events will (eventually)
6102 		 * be larger than it was before.  Once it becomes
6103 		 * substantially larger, the test below will cause
6104 		 * the array to appear non-idle, and resync will slow
6105 		 * down.
6106 		 * If there is a lot of outstanding resync activity when
6107 		 * we set last_event to curr_events, then all that activity
6108 		 * completing might cause the array to appear non-idle
6109 		 * and resync will be slowed down even though there might
6110 		 * not have been non-resync activity.  This will only
6111 		 * happen once though.  'last_events' will soon reflect
6112 		 * the state where there is little or no outstanding
6113 		 * resync requests, and further resync activity will
6114 		 * always make curr_events less than last_events.
6115 		 *
6116 		 */
6117 		if (init || curr_events - rdev->last_events > 64) {
6118 			rdev->last_events = curr_events;
6119 			idle = 0;
6120 		}
6121 	}
6122 	rcu_read_unlock();
6123 	return idle;
6124 }
6125 
6126 void md_done_sync(mddev_t *mddev, int blocks, int ok)
6127 {
6128 	/* another "blocks" (512byte) blocks have been synced */
6129 	atomic_sub(blocks, &mddev->recovery_active);
6130 	wake_up(&mddev->recovery_wait);
6131 	if (!ok) {
6132 		set_bit(MD_RECOVERY_INTR, &mddev->recovery);
6133 		md_wakeup_thread(mddev->thread);
6134 		// stop recovery, signal do_sync ....
6135 	}
6136 }
6137 
6138 
6139 /* md_write_start(mddev, bi)
6140  * If we need to update some array metadata (e.g. 'active' flag
6141  * in superblock) before writing, schedule a superblock update
6142  * and wait for it to complete.
6143  */
6144 void md_write_start(mddev_t *mddev, struct bio *bi)
6145 {
6146 	int did_change = 0;
6147 	if (bio_data_dir(bi) != WRITE)
6148 		return;
6149 
6150 	BUG_ON(mddev->ro == 1);
6151 	if (mddev->ro == 2) {
6152 		/* need to switch to read/write */
6153 		mddev->ro = 0;
6154 		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
6155 		md_wakeup_thread(mddev->thread);
6156 		md_wakeup_thread(mddev->sync_thread);
6157 		did_change = 1;
6158 	}
6159 	atomic_inc(&mddev->writes_pending);
6160 	if (mddev->safemode == 1)
6161 		mddev->safemode = 0;
6162 	if (mddev->in_sync) {
6163 		spin_lock_irq(&mddev->write_lock);
6164 		if (mddev->in_sync) {
6165 			mddev->in_sync = 0;
6166 			set_bit(MD_CHANGE_CLEAN, &mddev->flags);
6167 			md_wakeup_thread(mddev->thread);
6168 			did_change = 1;
6169 		}
6170 		spin_unlock_irq(&mddev->write_lock);
6171 	}
6172 	if (did_change)
6173 		sysfs_notify_dirent(mddev->sysfs_state);
6174 	wait_event(mddev->sb_wait,
6175 		   !test_bit(MD_CHANGE_CLEAN, &mddev->flags) &&
6176 		   !test_bit(MD_CHANGE_PENDING, &mddev->flags));
6177 }
6178 
6179 void md_write_end(mddev_t *mddev)
6180 {
6181 	if (atomic_dec_and_test(&mddev->writes_pending)) {
6182 		if (mddev->safemode == 2)
6183 			md_wakeup_thread(mddev->thread);
6184 		else if (mddev->safemode_delay)
6185 			mod_timer(&mddev->safemode_timer, jiffies + mddev->safemode_delay);
6186 	}
6187 }
6188 
6189 /* md_allow_write(mddev)
6190  * Calling this ensures that the array is marked 'active' so that writes
6191  * may proceed without blocking.  It is important to call this before
6192  * attempting a GFP_KERNEL allocation while holding the mddev lock.
6193  * Must be called with mddev_lock held.
6194  *
6195  * In the ->external case MD_CHANGE_CLEAN can not be cleared until mddev->lock
6196  * is dropped, so return -EAGAIN after notifying userspace.
6197  */
6198 int md_allow_write(mddev_t *mddev)
6199 {
6200 	if (!mddev->pers)
6201 		return 0;
6202 	if (mddev->ro)
6203 		return 0;
6204 	if (!mddev->pers->sync_request)
6205 		return 0;
6206 
6207 	spin_lock_irq(&mddev->write_lock);
6208 	if (mddev->in_sync) {
6209 		mddev->in_sync = 0;
6210 		set_bit(MD_CHANGE_CLEAN, &mddev->flags);
6211 		if (mddev->safemode_delay &&
6212 		    mddev->safemode == 0)
6213 			mddev->safemode = 1;
6214 		spin_unlock_irq(&mddev->write_lock);
6215 		md_update_sb(mddev, 0);
6216 		sysfs_notify_dirent(mddev->sysfs_state);
6217 	} else
6218 		spin_unlock_irq(&mddev->write_lock);
6219 
6220 	if (test_bit(MD_CHANGE_CLEAN, &mddev->flags))
6221 		return -EAGAIN;
6222 	else
6223 		return 0;
6224 }
6225 EXPORT_SYMBOL_GPL(md_allow_write);
6226 
6227 #define SYNC_MARKS	10
6228 #define	SYNC_MARK_STEP	(3*HZ)
6229 void md_do_sync(mddev_t *mddev)
6230 {
6231 	mddev_t *mddev2;
6232 	unsigned int currspeed = 0,
6233 		 window;
6234 	sector_t max_sectors,j, io_sectors;
6235 	unsigned long mark[SYNC_MARKS];
6236 	sector_t mark_cnt[SYNC_MARKS];
6237 	int last_mark,m;
6238 	struct list_head *tmp;
6239 	sector_t last_check;
6240 	int skipped = 0;
6241 	mdk_rdev_t *rdev;
6242 	char *desc;
6243 
6244 	/* just incase thread restarts... */
6245 	if (test_bit(MD_RECOVERY_DONE, &mddev->recovery))
6246 		return;
6247 	if (mddev->ro) /* never try to sync a read-only array */
6248 		return;
6249 
6250 	if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
6251 		if (test_bit(MD_RECOVERY_CHECK, &mddev->recovery))
6252 			desc = "data-check";
6253 		else if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
6254 			desc = "requested-resync";
6255 		else
6256 			desc = "resync";
6257 	} else if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
6258 		desc = "reshape";
6259 	else
6260 		desc = "recovery";
6261 
6262 	/* we overload curr_resync somewhat here.
6263 	 * 0 == not engaged in resync at all
6264 	 * 2 == checking that there is no conflict with another sync
6265 	 * 1 == like 2, but have yielded to allow conflicting resync to
6266 	 *		commense
6267 	 * other == active in resync - this many blocks
6268 	 *
6269 	 * Before starting a resync we must have set curr_resync to
6270 	 * 2, and then checked that every "conflicting" array has curr_resync
6271 	 * less than ours.  When we find one that is the same or higher
6272 	 * we wait on resync_wait.  To avoid deadlock, we reduce curr_resync
6273 	 * to 1 if we choose to yield (based arbitrarily on address of mddev structure).
6274 	 * This will mean we have to start checking from the beginning again.
6275 	 *
6276 	 */
6277 
6278 	do {
6279 		mddev->curr_resync = 2;
6280 
6281 	try_again:
6282 		if (kthread_should_stop()) {
6283 			set_bit(MD_RECOVERY_INTR, &mddev->recovery);
6284 			goto skip;
6285 		}
6286 		for_each_mddev(mddev2, tmp) {
6287 			if (mddev2 == mddev)
6288 				continue;
6289 			if (!mddev->parallel_resync
6290 			&&  mddev2->curr_resync
6291 			&&  match_mddev_units(mddev, mddev2)) {
6292 				DEFINE_WAIT(wq);
6293 				if (mddev < mddev2 && mddev->curr_resync == 2) {
6294 					/* arbitrarily yield */
6295 					mddev->curr_resync = 1;
6296 					wake_up(&resync_wait);
6297 				}
6298 				if (mddev > mddev2 && mddev->curr_resync == 1)
6299 					/* no need to wait here, we can wait the next
6300 					 * time 'round when curr_resync == 2
6301 					 */
6302 					continue;
6303 				/* We need to wait 'interruptible' so as not to
6304 				 * contribute to the load average, and not to
6305 				 * be caught by 'softlockup'
6306 				 */
6307 				prepare_to_wait(&resync_wait, &wq, TASK_INTERRUPTIBLE);
6308 				if (!kthread_should_stop() &&
6309 				    mddev2->curr_resync >= mddev->curr_resync) {
6310 					printk(KERN_INFO "md: delaying %s of %s"
6311 					       " until %s has finished (they"
6312 					       " share one or more physical units)\n",
6313 					       desc, mdname(mddev), mdname(mddev2));
6314 					mddev_put(mddev2);
6315 					if (signal_pending(current))
6316 						flush_signals(current);
6317 					schedule();
6318 					finish_wait(&resync_wait, &wq);
6319 					goto try_again;
6320 				}
6321 				finish_wait(&resync_wait, &wq);
6322 			}
6323 		}
6324 	} while (mddev->curr_resync < 2);
6325 
6326 	j = 0;
6327 	if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
6328 		/* resync follows the size requested by the personality,
6329 		 * which defaults to physical size, but can be virtual size
6330 		 */
6331 		max_sectors = mddev->resync_max_sectors;
6332 		mddev->resync_mismatches = 0;
6333 		/* we don't use the checkpoint if there's a bitmap */
6334 		if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
6335 			j = mddev->resync_min;
6336 		else if (!mddev->bitmap)
6337 			j = mddev->recovery_cp;
6338 
6339 	} else if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
6340 		max_sectors = mddev->dev_sectors;
6341 	else {
6342 		/* recovery follows the physical size of devices */
6343 		max_sectors = mddev->dev_sectors;
6344 		j = MaxSector;
6345 		list_for_each_entry(rdev, &mddev->disks, same_set)
6346 			if (rdev->raid_disk >= 0 &&
6347 			    !test_bit(Faulty, &rdev->flags) &&
6348 			    !test_bit(In_sync, &rdev->flags) &&
6349 			    rdev->recovery_offset < j)
6350 				j = rdev->recovery_offset;
6351 	}
6352 
6353 	printk(KERN_INFO "md: %s of RAID array %s\n", desc, mdname(mddev));
6354 	printk(KERN_INFO "md: minimum _guaranteed_  speed:"
6355 		" %d KB/sec/disk.\n", speed_min(mddev));
6356 	printk(KERN_INFO "md: using maximum available idle IO bandwidth "
6357 	       "(but not more than %d KB/sec) for %s.\n",
6358 	       speed_max(mddev), desc);
6359 
6360 	is_mddev_idle(mddev, 1); /* this initializes IO event counters */
6361 
6362 	io_sectors = 0;
6363 	for (m = 0; m < SYNC_MARKS; m++) {
6364 		mark[m] = jiffies;
6365 		mark_cnt[m] = io_sectors;
6366 	}
6367 	last_mark = 0;
6368 	mddev->resync_mark = mark[last_mark];
6369 	mddev->resync_mark_cnt = mark_cnt[last_mark];
6370 
6371 	/*
6372 	 * Tune reconstruction:
6373 	 */
6374 	window = 32*(PAGE_SIZE/512);
6375 	printk(KERN_INFO "md: using %dk window, over a total of %llu blocks.\n",
6376 		window/2,(unsigned long long) max_sectors/2);
6377 
6378 	atomic_set(&mddev->recovery_active, 0);
6379 	last_check = 0;
6380 
6381 	if (j>2) {
6382 		printk(KERN_INFO
6383 		       "md: resuming %s of %s from checkpoint.\n",
6384 		       desc, mdname(mddev));
6385 		mddev->curr_resync = j;
6386 	}
6387 
6388 	while (j < max_sectors) {
6389 		sector_t sectors;
6390 
6391 		skipped = 0;
6392 
6393 		if (!test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
6394 		    ((mddev->curr_resync > mddev->curr_resync_completed &&
6395 		      (mddev->curr_resync - mddev->curr_resync_completed)
6396 		      > (max_sectors >> 4)) ||
6397 		     (j - mddev->curr_resync_completed)*2
6398 		     >= mddev->resync_max - mddev->curr_resync_completed
6399 			    )) {
6400 			/* time to update curr_resync_completed */
6401 			blk_unplug(mddev->queue);
6402 			wait_event(mddev->recovery_wait,
6403 				   atomic_read(&mddev->recovery_active) == 0);
6404 			mddev->curr_resync_completed =
6405 				mddev->curr_resync;
6406 			set_bit(MD_CHANGE_CLEAN, &mddev->flags);
6407 			sysfs_notify(&mddev->kobj, NULL, "sync_completed");
6408 		}
6409 
6410 		while (j >= mddev->resync_max && !kthread_should_stop()) {
6411 			/* As this condition is controlled by user-space,
6412 			 * we can block indefinitely, so use '_interruptible'
6413 			 * to avoid triggering warnings.
6414 			 */
6415 			flush_signals(current); /* just in case */
6416 			wait_event_interruptible(mddev->recovery_wait,
6417 						 mddev->resync_max > j
6418 						 || kthread_should_stop());
6419 		}
6420 
6421 		if (kthread_should_stop())
6422 			goto interrupted;
6423 
6424 		sectors = mddev->pers->sync_request(mddev, j, &skipped,
6425 						  currspeed < speed_min(mddev));
6426 		if (sectors == 0) {
6427 			set_bit(MD_RECOVERY_INTR, &mddev->recovery);
6428 			goto out;
6429 		}
6430 
6431 		if (!skipped) { /* actual IO requested */
6432 			io_sectors += sectors;
6433 			atomic_add(sectors, &mddev->recovery_active);
6434 		}
6435 
6436 		j += sectors;
6437 		if (j>1) mddev->curr_resync = j;
6438 		mddev->curr_mark_cnt = io_sectors;
6439 		if (last_check == 0)
6440 			/* this is the earliers that rebuilt will be
6441 			 * visible in /proc/mdstat
6442 			 */
6443 			md_new_event(mddev);
6444 
6445 		if (last_check + window > io_sectors || j == max_sectors)
6446 			continue;
6447 
6448 		last_check = io_sectors;
6449 
6450 		if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
6451 			break;
6452 
6453 	repeat:
6454 		if (time_after_eq(jiffies, mark[last_mark] + SYNC_MARK_STEP )) {
6455 			/* step marks */
6456 			int next = (last_mark+1) % SYNC_MARKS;
6457 
6458 			mddev->resync_mark = mark[next];
6459 			mddev->resync_mark_cnt = mark_cnt[next];
6460 			mark[next] = jiffies;
6461 			mark_cnt[next] = io_sectors - atomic_read(&mddev->recovery_active);
6462 			last_mark = next;
6463 		}
6464 
6465 
6466 		if (kthread_should_stop())
6467 			goto interrupted;
6468 
6469 
6470 		/*
6471 		 * this loop exits only if either when we are slower than
6472 		 * the 'hard' speed limit, or the system was IO-idle for
6473 		 * a jiffy.
6474 		 * the system might be non-idle CPU-wise, but we only care
6475 		 * about not overloading the IO subsystem. (things like an
6476 		 * e2fsck being done on the RAID array should execute fast)
6477 		 */
6478 		blk_unplug(mddev->queue);
6479 		cond_resched();
6480 
6481 		currspeed = ((unsigned long)(io_sectors-mddev->resync_mark_cnt))/2
6482 			/((jiffies-mddev->resync_mark)/HZ +1) +1;
6483 
6484 		if (currspeed > speed_min(mddev)) {
6485 			if ((currspeed > speed_max(mddev)) ||
6486 					!is_mddev_idle(mddev, 0)) {
6487 				msleep(500);
6488 				goto repeat;
6489 			}
6490 		}
6491 	}
6492 	printk(KERN_INFO "md: %s: %s done.\n",mdname(mddev), desc);
6493 	/*
6494 	 * this also signals 'finished resyncing' to md_stop
6495 	 */
6496  out:
6497 	blk_unplug(mddev->queue);
6498 
6499 	wait_event(mddev->recovery_wait, !atomic_read(&mddev->recovery_active));
6500 
6501 	/* tell personality that we are finished */
6502 	mddev->pers->sync_request(mddev, max_sectors, &skipped, 1);
6503 
6504 	if (!test_bit(MD_RECOVERY_CHECK, &mddev->recovery) &&
6505 	    mddev->curr_resync > 2) {
6506 		if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
6507 			if (test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
6508 				if (mddev->curr_resync >= mddev->recovery_cp) {
6509 					printk(KERN_INFO
6510 					       "md: checkpointing %s of %s.\n",
6511 					       desc, mdname(mddev));
6512 					mddev->recovery_cp = mddev->curr_resync;
6513 				}
6514 			} else
6515 				mddev->recovery_cp = MaxSector;
6516 		} else {
6517 			if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery))
6518 				mddev->curr_resync = MaxSector;
6519 			list_for_each_entry(rdev, &mddev->disks, same_set)
6520 				if (rdev->raid_disk >= 0 &&
6521 				    !test_bit(Faulty, &rdev->flags) &&
6522 				    !test_bit(In_sync, &rdev->flags) &&
6523 				    rdev->recovery_offset < mddev->curr_resync)
6524 					rdev->recovery_offset = mddev->curr_resync;
6525 		}
6526 	}
6527 	set_bit(MD_CHANGE_DEVS, &mddev->flags);
6528 
6529  skip:
6530 	mddev->curr_resync = 0;
6531 	mddev->curr_resync_completed = 0;
6532 	if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery))
6533 		/* We completed so max setting can be forgotten. */
6534 		mddev->resync_max = MaxSector;
6535 	sysfs_notify(&mddev->kobj, NULL, "sync_completed");
6536 	wake_up(&resync_wait);
6537 	set_bit(MD_RECOVERY_DONE, &mddev->recovery);
6538 	md_wakeup_thread(mddev->thread);
6539 	return;
6540 
6541  interrupted:
6542 	/*
6543 	 * got a signal, exit.
6544 	 */
6545 	printk(KERN_INFO
6546 	       "md: md_do_sync() got signal ... exiting\n");
6547 	set_bit(MD_RECOVERY_INTR, &mddev->recovery);
6548 	goto out;
6549 
6550 }
6551 EXPORT_SYMBOL_GPL(md_do_sync);
6552 
6553 
6554 static int remove_and_add_spares(mddev_t *mddev)
6555 {
6556 	mdk_rdev_t *rdev;
6557 	int spares = 0;
6558 
6559 	mddev->curr_resync_completed = 0;
6560 
6561 	list_for_each_entry(rdev, &mddev->disks, same_set)
6562 		if (rdev->raid_disk >= 0 &&
6563 		    !test_bit(Blocked, &rdev->flags) &&
6564 		    (test_bit(Faulty, &rdev->flags) ||
6565 		     ! test_bit(In_sync, &rdev->flags)) &&
6566 		    atomic_read(&rdev->nr_pending)==0) {
6567 			if (mddev->pers->hot_remove_disk(
6568 				    mddev, rdev->raid_disk)==0) {
6569 				char nm[20];
6570 				sprintf(nm,"rd%d", rdev->raid_disk);
6571 				sysfs_remove_link(&mddev->kobj, nm);
6572 				rdev->raid_disk = -1;
6573 			}
6574 		}
6575 
6576 	if (mddev->degraded && ! mddev->ro && !mddev->recovery_disabled) {
6577 		list_for_each_entry(rdev, &mddev->disks, same_set) {
6578 			if (rdev->raid_disk >= 0 &&
6579 			    !test_bit(In_sync, &rdev->flags) &&
6580 			    !test_bit(Blocked, &rdev->flags))
6581 				spares++;
6582 			if (rdev->raid_disk < 0
6583 			    && !test_bit(Faulty, &rdev->flags)) {
6584 				rdev->recovery_offset = 0;
6585 				if (mddev->pers->
6586 				    hot_add_disk(mddev, rdev) == 0) {
6587 					char nm[20];
6588 					sprintf(nm, "rd%d", rdev->raid_disk);
6589 					if (sysfs_create_link(&mddev->kobj,
6590 							      &rdev->kobj, nm))
6591 						printk(KERN_WARNING
6592 						       "md: cannot register "
6593 						       "%s for %s\n",
6594 						       nm, mdname(mddev));
6595 					spares++;
6596 					md_new_event(mddev);
6597 				} else
6598 					break;
6599 			}
6600 		}
6601 	}
6602 	return spares;
6603 }
6604 /*
6605  * This routine is regularly called by all per-raid-array threads to
6606  * deal with generic issues like resync and super-block update.
6607  * Raid personalities that don't have a thread (linear/raid0) do not
6608  * need this as they never do any recovery or update the superblock.
6609  *
6610  * It does not do any resync itself, but rather "forks" off other threads
6611  * to do that as needed.
6612  * When it is determined that resync is needed, we set MD_RECOVERY_RUNNING in
6613  * "->recovery" and create a thread at ->sync_thread.
6614  * When the thread finishes it sets MD_RECOVERY_DONE
6615  * and wakeups up this thread which will reap the thread and finish up.
6616  * This thread also removes any faulty devices (with nr_pending == 0).
6617  *
6618  * The overall approach is:
6619  *  1/ if the superblock needs updating, update it.
6620  *  2/ If a recovery thread is running, don't do anything else.
6621  *  3/ If recovery has finished, clean up, possibly marking spares active.
6622  *  4/ If there are any faulty devices, remove them.
6623  *  5/ If array is degraded, try to add spares devices
6624  *  6/ If array has spares or is not in-sync, start a resync thread.
6625  */
6626 void md_check_recovery(mddev_t *mddev)
6627 {
6628 	mdk_rdev_t *rdev;
6629 
6630 
6631 	if (mddev->bitmap)
6632 		bitmap_daemon_work(mddev->bitmap);
6633 
6634 	if (mddev->ro)
6635 		return;
6636 
6637 	if (signal_pending(current)) {
6638 		if (mddev->pers->sync_request && !mddev->external) {
6639 			printk(KERN_INFO "md: %s in immediate safe mode\n",
6640 			       mdname(mddev));
6641 			mddev->safemode = 2;
6642 		}
6643 		flush_signals(current);
6644 	}
6645 
6646 	if (mddev->ro && !test_bit(MD_RECOVERY_NEEDED, &mddev->recovery))
6647 		return;
6648 	if ( ! (
6649 		(mddev->flags && !mddev->external) ||
6650 		test_bit(MD_RECOVERY_NEEDED, &mddev->recovery) ||
6651 		test_bit(MD_RECOVERY_DONE, &mddev->recovery) ||
6652 		(mddev->external == 0 && mddev->safemode == 1) ||
6653 		(mddev->safemode == 2 && ! atomic_read(&mddev->writes_pending)
6654 		 && !mddev->in_sync && mddev->recovery_cp == MaxSector)
6655 		))
6656 		return;
6657 
6658 	if (mddev_trylock(mddev)) {
6659 		int spares = 0;
6660 
6661 		if (mddev->ro) {
6662 			/* Only thing we do on a ro array is remove
6663 			 * failed devices.
6664 			 */
6665 			remove_and_add_spares(mddev);
6666 			clear_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
6667 			goto unlock;
6668 		}
6669 
6670 		if (!mddev->external) {
6671 			int did_change = 0;
6672 			spin_lock_irq(&mddev->write_lock);
6673 			if (mddev->safemode &&
6674 			    !atomic_read(&mddev->writes_pending) &&
6675 			    !mddev->in_sync &&
6676 			    mddev->recovery_cp == MaxSector) {
6677 				mddev->in_sync = 1;
6678 				did_change = 1;
6679 				if (mddev->persistent)
6680 					set_bit(MD_CHANGE_CLEAN, &mddev->flags);
6681 			}
6682 			if (mddev->safemode == 1)
6683 				mddev->safemode = 0;
6684 			spin_unlock_irq(&mddev->write_lock);
6685 			if (did_change)
6686 				sysfs_notify_dirent(mddev->sysfs_state);
6687 		}
6688 
6689 		if (mddev->flags)
6690 			md_update_sb(mddev, 0);
6691 
6692 		list_for_each_entry(rdev, &mddev->disks, same_set)
6693 			if (test_and_clear_bit(StateChanged, &rdev->flags))
6694 				sysfs_notify_dirent(rdev->sysfs_state);
6695 
6696 
6697 		if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) &&
6698 		    !test_bit(MD_RECOVERY_DONE, &mddev->recovery)) {
6699 			/* resync/recovery still happening */
6700 			clear_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
6701 			goto unlock;
6702 		}
6703 		if (mddev->sync_thread) {
6704 			/* resync has finished, collect result */
6705 			md_unregister_thread(mddev->sync_thread);
6706 			mddev->sync_thread = NULL;
6707 			if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery) &&
6708 			    !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
6709 				/* success...*/
6710 				/* activate any spares */
6711 				if (mddev->pers->spare_active(mddev))
6712 					sysfs_notify(&mddev->kobj, NULL,
6713 						     "degraded");
6714 			}
6715 			if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
6716 			    mddev->pers->finish_reshape)
6717 				mddev->pers->finish_reshape(mddev);
6718 			md_update_sb(mddev, 1);
6719 
6720 			/* if array is no-longer degraded, then any saved_raid_disk
6721 			 * information must be scrapped
6722 			 */
6723 			if (!mddev->degraded)
6724 				list_for_each_entry(rdev, &mddev->disks, same_set)
6725 					rdev->saved_raid_disk = -1;
6726 
6727 			mddev->recovery = 0;
6728 			/* flag recovery needed just to double check */
6729 			set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
6730 			sysfs_notify_dirent(mddev->sysfs_action);
6731 			md_new_event(mddev);
6732 			goto unlock;
6733 		}
6734 		/* Set RUNNING before clearing NEEDED to avoid
6735 		 * any transients in the value of "sync_action".
6736 		 */
6737 		set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
6738 		clear_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
6739 		/* Clear some bits that don't mean anything, but
6740 		 * might be left set
6741 		 */
6742 		clear_bit(MD_RECOVERY_INTR, &mddev->recovery);
6743 		clear_bit(MD_RECOVERY_DONE, &mddev->recovery);
6744 
6745 		if (test_bit(MD_RECOVERY_FROZEN, &mddev->recovery))
6746 			goto unlock;
6747 		/* no recovery is running.
6748 		 * remove any failed drives, then
6749 		 * add spares if possible.
6750 		 * Spare are also removed and re-added, to allow
6751 		 * the personality to fail the re-add.
6752 		 */
6753 
6754 		if (mddev->reshape_position != MaxSector) {
6755 			if (mddev->pers->check_reshape == NULL ||
6756 			    mddev->pers->check_reshape(mddev) != 0)
6757 				/* Cannot proceed */
6758 				goto unlock;
6759 			set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
6760 			clear_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
6761 		} else if ((spares = remove_and_add_spares(mddev))) {
6762 			clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
6763 			clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
6764 			clear_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
6765 			set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
6766 		} else if (mddev->recovery_cp < MaxSector) {
6767 			set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
6768 			clear_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
6769 		} else if (!test_bit(MD_RECOVERY_SYNC, &mddev->recovery))
6770 			/* nothing to be done ... */
6771 			goto unlock;
6772 
6773 		if (mddev->pers->sync_request) {
6774 			if (spares && mddev->bitmap && ! mddev->bitmap->file) {
6775 				/* We are adding a device or devices to an array
6776 				 * which has the bitmap stored on all devices.
6777 				 * So make sure all bitmap pages get written
6778 				 */
6779 				bitmap_write_all(mddev->bitmap);
6780 			}
6781 			mddev->sync_thread = md_register_thread(md_do_sync,
6782 								mddev,
6783 								"resync");
6784 			if (!mddev->sync_thread) {
6785 				printk(KERN_ERR "%s: could not start resync"
6786 					" thread...\n",
6787 					mdname(mddev));
6788 				/* leave the spares where they are, it shouldn't hurt */
6789 				mddev->recovery = 0;
6790 			} else
6791 				md_wakeup_thread(mddev->sync_thread);
6792 			sysfs_notify_dirent(mddev->sysfs_action);
6793 			md_new_event(mddev);
6794 		}
6795 	unlock:
6796 		if (!mddev->sync_thread) {
6797 			clear_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
6798 			if (test_and_clear_bit(MD_RECOVERY_RECOVER,
6799 					       &mddev->recovery))
6800 				if (mddev->sysfs_action)
6801 					sysfs_notify_dirent(mddev->sysfs_action);
6802 		}
6803 		mddev_unlock(mddev);
6804 	}
6805 }
6806 
6807 void md_wait_for_blocked_rdev(mdk_rdev_t *rdev, mddev_t *mddev)
6808 {
6809 	sysfs_notify_dirent(rdev->sysfs_state);
6810 	wait_event_timeout(rdev->blocked_wait,
6811 			   !test_bit(Blocked, &rdev->flags),
6812 			   msecs_to_jiffies(5000));
6813 	rdev_dec_pending(rdev, mddev);
6814 }
6815 EXPORT_SYMBOL(md_wait_for_blocked_rdev);
6816 
6817 static int md_notify_reboot(struct notifier_block *this,
6818 			    unsigned long code, void *x)
6819 {
6820 	struct list_head *tmp;
6821 	mddev_t *mddev;
6822 
6823 	if ((code == SYS_DOWN) || (code == SYS_HALT) || (code == SYS_POWER_OFF)) {
6824 
6825 		printk(KERN_INFO "md: stopping all md devices.\n");
6826 
6827 		for_each_mddev(mddev, tmp)
6828 			if (mddev_trylock(mddev)) {
6829 				/* Force a switch to readonly even array
6830 				 * appears to still be in use.  Hence
6831 				 * the '100'.
6832 				 */
6833 				do_md_stop(mddev, 1, 100);
6834 				mddev_unlock(mddev);
6835 			}
6836 		/*
6837 		 * certain more exotic SCSI devices are known to be
6838 		 * volatile wrt too early system reboots. While the
6839 		 * right place to handle this issue is the given
6840 		 * driver, we do want to have a safe RAID driver ...
6841 		 */
6842 		mdelay(1000*1);
6843 	}
6844 	return NOTIFY_DONE;
6845 }
6846 
6847 static struct notifier_block md_notifier = {
6848 	.notifier_call	= md_notify_reboot,
6849 	.next		= NULL,
6850 	.priority	= INT_MAX, /* before any real devices */
6851 };
6852 
6853 static void md_geninit(void)
6854 {
6855 	dprintk("md: sizeof(mdp_super_t) = %d\n", (int)sizeof(mdp_super_t));
6856 
6857 	proc_create("mdstat", S_IRUGO, NULL, &md_seq_fops);
6858 }
6859 
6860 static int __init md_init(void)
6861 {
6862 	if (register_blkdev(MD_MAJOR, "md"))
6863 		return -1;
6864 	if ((mdp_major=register_blkdev(0, "mdp"))<=0) {
6865 		unregister_blkdev(MD_MAJOR, "md");
6866 		return -1;
6867 	}
6868 	blk_register_region(MKDEV(MD_MAJOR, 0), 1UL<<MINORBITS, THIS_MODULE,
6869 			    md_probe, NULL, NULL);
6870 	blk_register_region(MKDEV(mdp_major, 0), 1UL<<MINORBITS, THIS_MODULE,
6871 			    md_probe, NULL, NULL);
6872 
6873 	register_reboot_notifier(&md_notifier);
6874 	raid_table_header = register_sysctl_table(raid_root_table);
6875 
6876 	md_geninit();
6877 	return 0;
6878 }
6879 
6880 
6881 #ifndef MODULE
6882 
6883 /*
6884  * Searches all registered partitions for autorun RAID arrays
6885  * at boot time.
6886  */
6887 
6888 static LIST_HEAD(all_detected_devices);
6889 struct detected_devices_node {
6890 	struct list_head list;
6891 	dev_t dev;
6892 };
6893 
6894 void md_autodetect_dev(dev_t dev)
6895 {
6896 	struct detected_devices_node *node_detected_dev;
6897 
6898 	node_detected_dev = kzalloc(sizeof(*node_detected_dev), GFP_KERNEL);
6899 	if (node_detected_dev) {
6900 		node_detected_dev->dev = dev;
6901 		list_add_tail(&node_detected_dev->list, &all_detected_devices);
6902 	} else {
6903 		printk(KERN_CRIT "md: md_autodetect_dev: kzalloc failed"
6904 			", skipping dev(%d,%d)\n", MAJOR(dev), MINOR(dev));
6905 	}
6906 }
6907 
6908 
6909 static void autostart_arrays(int part)
6910 {
6911 	mdk_rdev_t *rdev;
6912 	struct detected_devices_node *node_detected_dev;
6913 	dev_t dev;
6914 	int i_scanned, i_passed;
6915 
6916 	i_scanned = 0;
6917 	i_passed = 0;
6918 
6919 	printk(KERN_INFO "md: Autodetecting RAID arrays.\n");
6920 
6921 	while (!list_empty(&all_detected_devices) && i_scanned < INT_MAX) {
6922 		i_scanned++;
6923 		node_detected_dev = list_entry(all_detected_devices.next,
6924 					struct detected_devices_node, list);
6925 		list_del(&node_detected_dev->list);
6926 		dev = node_detected_dev->dev;
6927 		kfree(node_detected_dev);
6928 		rdev = md_import_device(dev,0, 90);
6929 		if (IS_ERR(rdev))
6930 			continue;
6931 
6932 		if (test_bit(Faulty, &rdev->flags)) {
6933 			MD_BUG();
6934 			continue;
6935 		}
6936 		set_bit(AutoDetected, &rdev->flags);
6937 		list_add(&rdev->same_set, &pending_raid_disks);
6938 		i_passed++;
6939 	}
6940 
6941 	printk(KERN_INFO "md: Scanned %d and added %d devices.\n",
6942 						i_scanned, i_passed);
6943 
6944 	autorun_devices(part);
6945 }
6946 
6947 #endif /* !MODULE */
6948 
6949 static __exit void md_exit(void)
6950 {
6951 	mddev_t *mddev;
6952 	struct list_head *tmp;
6953 
6954 	blk_unregister_region(MKDEV(MD_MAJOR,0), 1U << MINORBITS);
6955 	blk_unregister_region(MKDEV(mdp_major,0), 1U << MINORBITS);
6956 
6957 	unregister_blkdev(MD_MAJOR,"md");
6958 	unregister_blkdev(mdp_major, "mdp");
6959 	unregister_reboot_notifier(&md_notifier);
6960 	unregister_sysctl_table(raid_table_header);
6961 	remove_proc_entry("mdstat", NULL);
6962 	for_each_mddev(mddev, tmp) {
6963 		export_array(mddev);
6964 		mddev->hold_active = 0;
6965 	}
6966 }
6967 
6968 subsys_initcall(md_init);
6969 module_exit(md_exit)
6970 
6971 static int get_ro(char *buffer, struct kernel_param *kp)
6972 {
6973 	return sprintf(buffer, "%d", start_readonly);
6974 }
6975 static int set_ro(const char *val, struct kernel_param *kp)
6976 {
6977 	char *e;
6978 	int num = simple_strtoul(val, &e, 10);
6979 	if (*val && (*e == '\0' || *e == '\n')) {
6980 		start_readonly = num;
6981 		return 0;
6982 	}
6983 	return -EINVAL;
6984 }
6985 
6986 module_param_call(start_ro, set_ro, get_ro, NULL, S_IRUSR|S_IWUSR);
6987 module_param(start_dirty_degraded, int, S_IRUGO|S_IWUSR);
6988 
6989 module_param_call(new_array, add_named_array, NULL, NULL, S_IWUSR);
6990 
6991 EXPORT_SYMBOL(register_md_personality);
6992 EXPORT_SYMBOL(unregister_md_personality);
6993 EXPORT_SYMBOL(md_error);
6994 EXPORT_SYMBOL(md_done_sync);
6995 EXPORT_SYMBOL(md_write_start);
6996 EXPORT_SYMBOL(md_write_end);
6997 EXPORT_SYMBOL(md_register_thread);
6998 EXPORT_SYMBOL(md_unregister_thread);
6999 EXPORT_SYMBOL(md_wakeup_thread);
7000 EXPORT_SYMBOL(md_check_recovery);
7001 MODULE_LICENSE("GPL");
7002 MODULE_ALIAS("md");
7003 MODULE_ALIAS_BLOCKDEV_MAJOR(MD_MAJOR);
7004