xref: /linux/drivers/md/md.c (revision 93d546399c2b7d66a54d5fbd5eee17de19246bf6)
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/raid/md.h>
37 #include <linux/raid/bitmap.h>
38 #include <linux/sysctl.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 
49 #define MAJOR_NR MD_MAJOR
50 
51 /* 63 partitions with the alternate major number (mdp) */
52 #define MdpMinorShift 6
53 
54 #define DEBUG 0
55 #define dprintk(x...) ((void)(DEBUG && printk(x)))
56 
57 
58 #ifndef MODULE
59 static void autostart_arrays(int part);
60 #endif
61 
62 static LIST_HEAD(pers_list);
63 static DEFINE_SPINLOCK(pers_lock);
64 
65 static void md_print_devices(void);
66 
67 static DECLARE_WAIT_QUEUE_HEAD(resync_wait);
68 
69 #define MD_BUG(x...) { printk("md: bug in file %s, line %d\n", __FILE__, __LINE__); md_print_devices(); }
70 
71 /*
72  * Current RAID-1,4,5 parallel reconstruction 'guaranteed speed limit'
73  * is 1000 KB/sec, so the extra system load does not show up that much.
74  * Increase it if you want to have more _guaranteed_ speed. Note that
75  * the RAID driver will use the maximum available bandwidth if the IO
76  * subsystem is idle. There is also an 'absolute maximum' reconstruction
77  * speed limit - in case reconstruction slows down your system despite
78  * idle IO detection.
79  *
80  * you can change it via /proc/sys/dev/raid/speed_limit_min and _max.
81  * or /sys/block/mdX/md/sync_speed_{min,max}
82  */
83 
84 static int sysctl_speed_limit_min = 1000;
85 static int sysctl_speed_limit_max = 200000;
86 static inline int speed_min(mddev_t *mddev)
87 {
88 	return mddev->sync_speed_min ?
89 		mddev->sync_speed_min : sysctl_speed_limit_min;
90 }
91 
92 static inline int speed_max(mddev_t *mddev)
93 {
94 	return mddev->sync_speed_max ?
95 		mddev->sync_speed_max : sysctl_speed_limit_max;
96 }
97 
98 static struct ctl_table_header *raid_table_header;
99 
100 static ctl_table raid_table[] = {
101 	{
102 		.ctl_name	= DEV_RAID_SPEED_LIMIT_MIN,
103 		.procname	= "speed_limit_min",
104 		.data		= &sysctl_speed_limit_min,
105 		.maxlen		= sizeof(int),
106 		.mode		= S_IRUGO|S_IWUSR,
107 		.proc_handler	= &proc_dointvec,
108 	},
109 	{
110 		.ctl_name	= DEV_RAID_SPEED_LIMIT_MAX,
111 		.procname	= "speed_limit_max",
112 		.data		= &sysctl_speed_limit_max,
113 		.maxlen		= sizeof(int),
114 		.mode		= S_IRUGO|S_IWUSR,
115 		.proc_handler	= &proc_dointvec,
116 	},
117 	{ .ctl_name = 0 }
118 };
119 
120 static ctl_table raid_dir_table[] = {
121 	{
122 		.ctl_name	= DEV_RAID,
123 		.procname	= "raid",
124 		.maxlen		= 0,
125 		.mode		= S_IRUGO|S_IXUGO,
126 		.child		= raid_table,
127 	},
128 	{ .ctl_name = 0 }
129 };
130 
131 static ctl_table raid_root_table[] = {
132 	{
133 		.ctl_name	= CTL_DEV,
134 		.procname	= "dev",
135 		.maxlen		= 0,
136 		.mode		= 0555,
137 		.child		= raid_dir_table,
138 	},
139 	{ .ctl_name = 0 }
140 };
141 
142 static struct block_device_operations md_fops;
143 
144 static int start_readonly;
145 
146 /*
147  * We have a system wide 'event count' that is incremented
148  * on any 'interesting' event, and readers of /proc/mdstat
149  * can use 'poll' or 'select' to find out when the event
150  * count increases.
151  *
152  * Events are:
153  *  start array, stop array, error, add device, remove device,
154  *  start build, activate spare
155  */
156 static DECLARE_WAIT_QUEUE_HEAD(md_event_waiters);
157 static atomic_t md_event_count;
158 void md_new_event(mddev_t *mddev)
159 {
160 	atomic_inc(&md_event_count);
161 	wake_up(&md_event_waiters);
162 }
163 EXPORT_SYMBOL_GPL(md_new_event);
164 
165 /* Alternate version that can be called from interrupts
166  * when calling sysfs_notify isn't needed.
167  */
168 static void md_new_event_inintr(mddev_t *mddev)
169 {
170 	atomic_inc(&md_event_count);
171 	wake_up(&md_event_waiters);
172 }
173 
174 /*
175  * Enables to iterate over all existing md arrays
176  * all_mddevs_lock protects this list.
177  */
178 static LIST_HEAD(all_mddevs);
179 static DEFINE_SPINLOCK(all_mddevs_lock);
180 
181 
182 /*
183  * iterates through all used mddevs in the system.
184  * We take care to grab the all_mddevs_lock whenever navigating
185  * the list, and to always hold a refcount when unlocked.
186  * Any code which breaks out of this loop while own
187  * a reference to the current mddev and must mddev_put it.
188  */
189 #define for_each_mddev(mddev,tmp)					\
190 									\
191 	for (({ spin_lock(&all_mddevs_lock); 				\
192 		tmp = all_mddevs.next;					\
193 		mddev = NULL;});					\
194 	     ({ if (tmp != &all_mddevs)					\
195 			mddev_get(list_entry(tmp, mddev_t, all_mddevs));\
196 		spin_unlock(&all_mddevs_lock);				\
197 		if (mddev) mddev_put(mddev);				\
198 		mddev = list_entry(tmp, mddev_t, all_mddevs);		\
199 		tmp != &all_mddevs;});					\
200 	     ({ spin_lock(&all_mddevs_lock);				\
201 		tmp = tmp->next;})					\
202 		)
203 
204 
205 static int md_fail_request(struct request_queue *q, struct bio *bio)
206 {
207 	bio_io_error(bio);
208 	return 0;
209 }
210 
211 static inline mddev_t *mddev_get(mddev_t *mddev)
212 {
213 	atomic_inc(&mddev->active);
214 	return mddev;
215 }
216 
217 static void mddev_put(mddev_t *mddev)
218 {
219 	if (!atomic_dec_and_lock(&mddev->active, &all_mddevs_lock))
220 		return;
221 	if (!mddev->raid_disks && list_empty(&mddev->disks)) {
222 		list_del(&mddev->all_mddevs);
223 		spin_unlock(&all_mddevs_lock);
224 		blk_cleanup_queue(mddev->queue);
225 		if (mddev->sysfs_state)
226 			sysfs_put(mddev->sysfs_state);
227 		mddev->sysfs_state = NULL;
228 		kobject_put(&mddev->kobj);
229 	} else
230 		spin_unlock(&all_mddevs_lock);
231 }
232 
233 static mddev_t * mddev_find(dev_t unit)
234 {
235 	mddev_t *mddev, *new = NULL;
236 
237  retry:
238 	spin_lock(&all_mddevs_lock);
239 	list_for_each_entry(mddev, &all_mddevs, all_mddevs)
240 		if (mddev->unit == unit) {
241 			mddev_get(mddev);
242 			spin_unlock(&all_mddevs_lock);
243 			kfree(new);
244 			return mddev;
245 		}
246 
247 	if (new) {
248 		list_add(&new->all_mddevs, &all_mddevs);
249 		spin_unlock(&all_mddevs_lock);
250 		return new;
251 	}
252 	spin_unlock(&all_mddevs_lock);
253 
254 	new = kzalloc(sizeof(*new), GFP_KERNEL);
255 	if (!new)
256 		return NULL;
257 
258 	new->unit = unit;
259 	if (MAJOR(unit) == MD_MAJOR)
260 		new->md_minor = MINOR(unit);
261 	else
262 		new->md_minor = MINOR(unit) >> MdpMinorShift;
263 
264 	mutex_init(&new->reconfig_mutex);
265 	INIT_LIST_HEAD(&new->disks);
266 	INIT_LIST_HEAD(&new->all_mddevs);
267 	init_timer(&new->safemode_timer);
268 	atomic_set(&new->active, 1);
269 	atomic_set(&new->openers, 0);
270 	spin_lock_init(&new->write_lock);
271 	init_waitqueue_head(&new->sb_wait);
272 	init_waitqueue_head(&new->recovery_wait);
273 	new->reshape_position = MaxSector;
274 	new->resync_min = 0;
275 	new->resync_max = MaxSector;
276 	new->level = LEVEL_NONE;
277 
278 	new->queue = blk_alloc_queue(GFP_KERNEL);
279 	if (!new->queue) {
280 		kfree(new);
281 		return NULL;
282 	}
283 	/* Can be unlocked because the queue is new: no concurrency */
284 	queue_flag_set_unlocked(QUEUE_FLAG_CLUSTER, new->queue);
285 
286 	blk_queue_make_request(new->queue, md_fail_request);
287 
288 	goto retry;
289 }
290 
291 static inline int mddev_lock(mddev_t * mddev)
292 {
293 	return mutex_lock_interruptible(&mddev->reconfig_mutex);
294 }
295 
296 static inline int mddev_trylock(mddev_t * mddev)
297 {
298 	return mutex_trylock(&mddev->reconfig_mutex);
299 }
300 
301 static inline void mddev_unlock(mddev_t * mddev)
302 {
303 	mutex_unlock(&mddev->reconfig_mutex);
304 
305 	md_wakeup_thread(mddev->thread);
306 }
307 
308 static mdk_rdev_t * find_rdev_nr(mddev_t *mddev, int nr)
309 {
310 	mdk_rdev_t * rdev;
311 	struct list_head *tmp;
312 
313 	rdev_for_each(rdev, tmp, mddev) {
314 		if (rdev->desc_nr == nr)
315 			return rdev;
316 	}
317 	return NULL;
318 }
319 
320 static mdk_rdev_t * find_rdev(mddev_t * mddev, dev_t dev)
321 {
322 	struct list_head *tmp;
323 	mdk_rdev_t *rdev;
324 
325 	rdev_for_each(rdev, tmp, mddev) {
326 		if (rdev->bdev->bd_dev == dev)
327 			return rdev;
328 	}
329 	return NULL;
330 }
331 
332 static struct mdk_personality *find_pers(int level, char *clevel)
333 {
334 	struct mdk_personality *pers;
335 	list_for_each_entry(pers, &pers_list, list) {
336 		if (level != LEVEL_NONE && pers->level == level)
337 			return pers;
338 		if (strcmp(pers->name, clevel)==0)
339 			return pers;
340 	}
341 	return NULL;
342 }
343 
344 /* return the offset of the super block in 512byte sectors */
345 static inline sector_t calc_dev_sboffset(struct block_device *bdev)
346 {
347 	sector_t num_sectors = bdev->bd_inode->i_size / 512;
348 	return MD_NEW_SIZE_SECTORS(num_sectors);
349 }
350 
351 static sector_t calc_num_sectors(mdk_rdev_t *rdev, unsigned chunk_size)
352 {
353 	sector_t num_sectors = rdev->sb_start;
354 
355 	if (chunk_size)
356 		num_sectors &= ~((sector_t)chunk_size/512 - 1);
357 	return num_sectors;
358 }
359 
360 static int alloc_disk_sb(mdk_rdev_t * rdev)
361 {
362 	if (rdev->sb_page)
363 		MD_BUG();
364 
365 	rdev->sb_page = alloc_page(GFP_KERNEL);
366 	if (!rdev->sb_page) {
367 		printk(KERN_ALERT "md: out of memory.\n");
368 		return -ENOMEM;
369 	}
370 
371 	return 0;
372 }
373 
374 static void free_disk_sb(mdk_rdev_t * rdev)
375 {
376 	if (rdev->sb_page) {
377 		put_page(rdev->sb_page);
378 		rdev->sb_loaded = 0;
379 		rdev->sb_page = NULL;
380 		rdev->sb_start = 0;
381 		rdev->size = 0;
382 	}
383 }
384 
385 
386 static void super_written(struct bio *bio, int error)
387 {
388 	mdk_rdev_t *rdev = bio->bi_private;
389 	mddev_t *mddev = rdev->mddev;
390 
391 	if (error || !test_bit(BIO_UPTODATE, &bio->bi_flags)) {
392 		printk("md: super_written gets error=%d, uptodate=%d\n",
393 		       error, test_bit(BIO_UPTODATE, &bio->bi_flags));
394 		WARN_ON(test_bit(BIO_UPTODATE, &bio->bi_flags));
395 		md_error(mddev, rdev);
396 	}
397 
398 	if (atomic_dec_and_test(&mddev->pending_writes))
399 		wake_up(&mddev->sb_wait);
400 	bio_put(bio);
401 }
402 
403 static void super_written_barrier(struct bio *bio, int error)
404 {
405 	struct bio *bio2 = bio->bi_private;
406 	mdk_rdev_t *rdev = bio2->bi_private;
407 	mddev_t *mddev = rdev->mddev;
408 
409 	if (!test_bit(BIO_UPTODATE, &bio->bi_flags) &&
410 	    error == -EOPNOTSUPP) {
411 		unsigned long flags;
412 		/* barriers don't appear to be supported :-( */
413 		set_bit(BarriersNotsupp, &rdev->flags);
414 		mddev->barriers_work = 0;
415 		spin_lock_irqsave(&mddev->write_lock, flags);
416 		bio2->bi_next = mddev->biolist;
417 		mddev->biolist = bio2;
418 		spin_unlock_irqrestore(&mddev->write_lock, flags);
419 		wake_up(&mddev->sb_wait);
420 		bio_put(bio);
421 	} else {
422 		bio_put(bio2);
423 		bio->bi_private = rdev;
424 		super_written(bio, error);
425 	}
426 }
427 
428 void md_super_write(mddev_t *mddev, mdk_rdev_t *rdev,
429 		   sector_t sector, int size, struct page *page)
430 {
431 	/* write first size bytes of page to sector of rdev
432 	 * Increment mddev->pending_writes before returning
433 	 * and decrement it on completion, waking up sb_wait
434 	 * if zero is reached.
435 	 * If an error occurred, call md_error
436 	 *
437 	 * As we might need to resubmit the request if BIO_RW_BARRIER
438 	 * causes ENOTSUPP, we allocate a spare bio...
439 	 */
440 	struct bio *bio = bio_alloc(GFP_NOIO, 1);
441 	int rw = (1<<BIO_RW) | (1<<BIO_RW_SYNC);
442 
443 	bio->bi_bdev = rdev->bdev;
444 	bio->bi_sector = sector;
445 	bio_add_page(bio, page, size, 0);
446 	bio->bi_private = rdev;
447 	bio->bi_end_io = super_written;
448 	bio->bi_rw = rw;
449 
450 	atomic_inc(&mddev->pending_writes);
451 	if (!test_bit(BarriersNotsupp, &rdev->flags)) {
452 		struct bio *rbio;
453 		rw |= (1<<BIO_RW_BARRIER);
454 		rbio = bio_clone(bio, GFP_NOIO);
455 		rbio->bi_private = bio;
456 		rbio->bi_end_io = super_written_barrier;
457 		submit_bio(rw, rbio);
458 	} else
459 		submit_bio(rw, bio);
460 }
461 
462 void md_super_wait(mddev_t *mddev)
463 {
464 	/* wait for all superblock writes that were scheduled to complete.
465 	 * if any had to be retried (due to BARRIER problems), retry them
466 	 */
467 	DEFINE_WAIT(wq);
468 	for(;;) {
469 		prepare_to_wait(&mddev->sb_wait, &wq, TASK_UNINTERRUPTIBLE);
470 		if (atomic_read(&mddev->pending_writes)==0)
471 			break;
472 		while (mddev->biolist) {
473 			struct bio *bio;
474 			spin_lock_irq(&mddev->write_lock);
475 			bio = mddev->biolist;
476 			mddev->biolist = bio->bi_next ;
477 			bio->bi_next = NULL;
478 			spin_unlock_irq(&mddev->write_lock);
479 			submit_bio(bio->bi_rw, bio);
480 		}
481 		schedule();
482 	}
483 	finish_wait(&mddev->sb_wait, &wq);
484 }
485 
486 static void bi_complete(struct bio *bio, int error)
487 {
488 	complete((struct completion*)bio->bi_private);
489 }
490 
491 int sync_page_io(struct block_device *bdev, sector_t sector, int size,
492 		   struct page *page, int rw)
493 {
494 	struct bio *bio = bio_alloc(GFP_NOIO, 1);
495 	struct completion event;
496 	int ret;
497 
498 	rw |= (1 << BIO_RW_SYNC);
499 
500 	bio->bi_bdev = bdev;
501 	bio->bi_sector = sector;
502 	bio_add_page(bio, page, size, 0);
503 	init_completion(&event);
504 	bio->bi_private = &event;
505 	bio->bi_end_io = bi_complete;
506 	submit_bio(rw, bio);
507 	wait_for_completion(&event);
508 
509 	ret = test_bit(BIO_UPTODATE, &bio->bi_flags);
510 	bio_put(bio);
511 	return ret;
512 }
513 EXPORT_SYMBOL_GPL(sync_page_io);
514 
515 static int read_disk_sb(mdk_rdev_t * rdev, int size)
516 {
517 	char b[BDEVNAME_SIZE];
518 	if (!rdev->sb_page) {
519 		MD_BUG();
520 		return -EINVAL;
521 	}
522 	if (rdev->sb_loaded)
523 		return 0;
524 
525 
526 	if (!sync_page_io(rdev->bdev, rdev->sb_start, size, rdev->sb_page, READ))
527 		goto fail;
528 	rdev->sb_loaded = 1;
529 	return 0;
530 
531 fail:
532 	printk(KERN_WARNING "md: disabled device %s, could not read superblock.\n",
533 		bdevname(rdev->bdev,b));
534 	return -EINVAL;
535 }
536 
537 static int uuid_equal(mdp_super_t *sb1, mdp_super_t *sb2)
538 {
539 	return 	sb1->set_uuid0 == sb2->set_uuid0 &&
540 		sb1->set_uuid1 == sb2->set_uuid1 &&
541 		sb1->set_uuid2 == sb2->set_uuid2 &&
542 		sb1->set_uuid3 == sb2->set_uuid3;
543 }
544 
545 static int sb_equal(mdp_super_t *sb1, mdp_super_t *sb2)
546 {
547 	int ret;
548 	mdp_super_t *tmp1, *tmp2;
549 
550 	tmp1 = kmalloc(sizeof(*tmp1),GFP_KERNEL);
551 	tmp2 = kmalloc(sizeof(*tmp2),GFP_KERNEL);
552 
553 	if (!tmp1 || !tmp2) {
554 		ret = 0;
555 		printk(KERN_INFO "md.c sb_equal(): failed to allocate memory!\n");
556 		goto abort;
557 	}
558 
559 	*tmp1 = *sb1;
560 	*tmp2 = *sb2;
561 
562 	/*
563 	 * nr_disks is not constant
564 	 */
565 	tmp1->nr_disks = 0;
566 	tmp2->nr_disks = 0;
567 
568 	ret = (memcmp(tmp1, tmp2, MD_SB_GENERIC_CONSTANT_WORDS * 4) == 0);
569 abort:
570 	kfree(tmp1);
571 	kfree(tmp2);
572 	return ret;
573 }
574 
575 
576 static u32 md_csum_fold(u32 csum)
577 {
578 	csum = (csum & 0xffff) + (csum >> 16);
579 	return (csum & 0xffff) + (csum >> 16);
580 }
581 
582 static unsigned int calc_sb_csum(mdp_super_t * sb)
583 {
584 	u64 newcsum = 0;
585 	u32 *sb32 = (u32*)sb;
586 	int i;
587 	unsigned int disk_csum, csum;
588 
589 	disk_csum = sb->sb_csum;
590 	sb->sb_csum = 0;
591 
592 	for (i = 0; i < MD_SB_BYTES/4 ; i++)
593 		newcsum += sb32[i];
594 	csum = (newcsum & 0xffffffff) + (newcsum>>32);
595 
596 
597 #ifdef CONFIG_ALPHA
598 	/* This used to use csum_partial, which was wrong for several
599 	 * reasons including that different results are returned on
600 	 * different architectures.  It isn't critical that we get exactly
601 	 * the same return value as before (we always csum_fold before
602 	 * testing, and that removes any differences).  However as we
603 	 * know that csum_partial always returned a 16bit value on
604 	 * alphas, do a fold to maximise conformity to previous behaviour.
605 	 */
606 	sb->sb_csum = md_csum_fold(disk_csum);
607 #else
608 	sb->sb_csum = disk_csum;
609 #endif
610 	return csum;
611 }
612 
613 
614 /*
615  * Handle superblock details.
616  * We want to be able to handle multiple superblock formats
617  * so we have a common interface to them all, and an array of
618  * different handlers.
619  * We rely on user-space to write the initial superblock, and support
620  * reading and updating of superblocks.
621  * Interface methods are:
622  *   int load_super(mdk_rdev_t *dev, mdk_rdev_t *refdev, int minor_version)
623  *      loads and validates a superblock on dev.
624  *      if refdev != NULL, compare superblocks on both devices
625  *    Return:
626  *      0 - dev has a superblock that is compatible with refdev
627  *      1 - dev has a superblock that is compatible and newer than refdev
628  *          so dev should be used as the refdev in future
629  *     -EINVAL superblock incompatible or invalid
630  *     -othererror e.g. -EIO
631  *
632  *   int validate_super(mddev_t *mddev, mdk_rdev_t *dev)
633  *      Verify that dev is acceptable into mddev.
634  *       The first time, mddev->raid_disks will be 0, and data from
635  *       dev should be merged in.  Subsequent calls check that dev
636  *       is new enough.  Return 0 or -EINVAL
637  *
638  *   void sync_super(mddev_t *mddev, mdk_rdev_t *dev)
639  *     Update the superblock for rdev with data in mddev
640  *     This does not write to disc.
641  *
642  */
643 
644 struct super_type  {
645 	char		    *name;
646 	struct module	    *owner;
647 	int		    (*load_super)(mdk_rdev_t *rdev, mdk_rdev_t *refdev,
648 					  int minor_version);
649 	int		    (*validate_super)(mddev_t *mddev, mdk_rdev_t *rdev);
650 	void		    (*sync_super)(mddev_t *mddev, mdk_rdev_t *rdev);
651 	unsigned long long  (*rdev_size_change)(mdk_rdev_t *rdev,
652 						sector_t num_sectors);
653 };
654 
655 /*
656  * load_super for 0.90.0
657  */
658 static int super_90_load(mdk_rdev_t *rdev, mdk_rdev_t *refdev, int minor_version)
659 {
660 	char b[BDEVNAME_SIZE], b2[BDEVNAME_SIZE];
661 	mdp_super_t *sb;
662 	int ret;
663 
664 	/*
665 	 * Calculate the position of the superblock (512byte sectors),
666 	 * it's at the end of the disk.
667 	 *
668 	 * It also happens to be a multiple of 4Kb.
669 	 */
670 	rdev->sb_start = calc_dev_sboffset(rdev->bdev);
671 
672 	ret = read_disk_sb(rdev, MD_SB_BYTES);
673 	if (ret) return ret;
674 
675 	ret = -EINVAL;
676 
677 	bdevname(rdev->bdev, b);
678 	sb = (mdp_super_t*)page_address(rdev->sb_page);
679 
680 	if (sb->md_magic != MD_SB_MAGIC) {
681 		printk(KERN_ERR "md: invalid raid superblock magic on %s\n",
682 		       b);
683 		goto abort;
684 	}
685 
686 	if (sb->major_version != 0 ||
687 	    sb->minor_version < 90 ||
688 	    sb->minor_version > 91) {
689 		printk(KERN_WARNING "Bad version number %d.%d on %s\n",
690 			sb->major_version, sb->minor_version,
691 			b);
692 		goto abort;
693 	}
694 
695 	if (sb->raid_disks <= 0)
696 		goto abort;
697 
698 	if (md_csum_fold(calc_sb_csum(sb)) != md_csum_fold(sb->sb_csum)) {
699 		printk(KERN_WARNING "md: invalid superblock checksum on %s\n",
700 			b);
701 		goto abort;
702 	}
703 
704 	rdev->preferred_minor = sb->md_minor;
705 	rdev->data_offset = 0;
706 	rdev->sb_size = MD_SB_BYTES;
707 
708 	if (sb->state & (1<<MD_SB_BITMAP_PRESENT)) {
709 		if (sb->level != 1 && sb->level != 4
710 		    && sb->level != 5 && sb->level != 6
711 		    && sb->level != 10) {
712 			/* FIXME use a better test */
713 			printk(KERN_WARNING
714 			       "md: bitmaps not supported for this level.\n");
715 			goto abort;
716 		}
717 	}
718 
719 	if (sb->level == LEVEL_MULTIPATH)
720 		rdev->desc_nr = -1;
721 	else
722 		rdev->desc_nr = sb->this_disk.number;
723 
724 	if (!refdev) {
725 		ret = 1;
726 	} else {
727 		__u64 ev1, ev2;
728 		mdp_super_t *refsb = (mdp_super_t*)page_address(refdev->sb_page);
729 		if (!uuid_equal(refsb, sb)) {
730 			printk(KERN_WARNING "md: %s has different UUID to %s\n",
731 				b, bdevname(refdev->bdev,b2));
732 			goto abort;
733 		}
734 		if (!sb_equal(refsb, sb)) {
735 			printk(KERN_WARNING "md: %s has same UUID"
736 			       " but different superblock to %s\n",
737 			       b, bdevname(refdev->bdev, b2));
738 			goto abort;
739 		}
740 		ev1 = md_event(sb);
741 		ev2 = md_event(refsb);
742 		if (ev1 > ev2)
743 			ret = 1;
744 		else
745 			ret = 0;
746 	}
747 	rdev->size = calc_num_sectors(rdev, sb->chunk_size) / 2;
748 
749 	if (rdev->size < sb->size && sb->level > 1)
750 		/* "this cannot possibly happen" ... */
751 		ret = -EINVAL;
752 
753  abort:
754 	return ret;
755 }
756 
757 /*
758  * validate_super for 0.90.0
759  */
760 static int super_90_validate(mddev_t *mddev, mdk_rdev_t *rdev)
761 {
762 	mdp_disk_t *desc;
763 	mdp_super_t *sb = (mdp_super_t *)page_address(rdev->sb_page);
764 	__u64 ev1 = md_event(sb);
765 
766 	rdev->raid_disk = -1;
767 	clear_bit(Faulty, &rdev->flags);
768 	clear_bit(In_sync, &rdev->flags);
769 	clear_bit(WriteMostly, &rdev->flags);
770 	clear_bit(BarriersNotsupp, &rdev->flags);
771 
772 	if (mddev->raid_disks == 0) {
773 		mddev->major_version = 0;
774 		mddev->minor_version = sb->minor_version;
775 		mddev->patch_version = sb->patch_version;
776 		mddev->external = 0;
777 		mddev->chunk_size = sb->chunk_size;
778 		mddev->ctime = sb->ctime;
779 		mddev->utime = sb->utime;
780 		mddev->level = sb->level;
781 		mddev->clevel[0] = 0;
782 		mddev->layout = sb->layout;
783 		mddev->raid_disks = sb->raid_disks;
784 		mddev->size = sb->size;
785 		mddev->events = ev1;
786 		mddev->bitmap_offset = 0;
787 		mddev->default_bitmap_offset = MD_SB_BYTES >> 9;
788 
789 		if (mddev->minor_version >= 91) {
790 			mddev->reshape_position = sb->reshape_position;
791 			mddev->delta_disks = sb->delta_disks;
792 			mddev->new_level = sb->new_level;
793 			mddev->new_layout = sb->new_layout;
794 			mddev->new_chunk = sb->new_chunk;
795 		} else {
796 			mddev->reshape_position = MaxSector;
797 			mddev->delta_disks = 0;
798 			mddev->new_level = mddev->level;
799 			mddev->new_layout = mddev->layout;
800 			mddev->new_chunk = mddev->chunk_size;
801 		}
802 
803 		if (sb->state & (1<<MD_SB_CLEAN))
804 			mddev->recovery_cp = MaxSector;
805 		else {
806 			if (sb->events_hi == sb->cp_events_hi &&
807 				sb->events_lo == sb->cp_events_lo) {
808 				mddev->recovery_cp = sb->recovery_cp;
809 			} else
810 				mddev->recovery_cp = 0;
811 		}
812 
813 		memcpy(mddev->uuid+0, &sb->set_uuid0, 4);
814 		memcpy(mddev->uuid+4, &sb->set_uuid1, 4);
815 		memcpy(mddev->uuid+8, &sb->set_uuid2, 4);
816 		memcpy(mddev->uuid+12,&sb->set_uuid3, 4);
817 
818 		mddev->max_disks = MD_SB_DISKS;
819 
820 		if (sb->state & (1<<MD_SB_BITMAP_PRESENT) &&
821 		    mddev->bitmap_file == NULL)
822 			mddev->bitmap_offset = mddev->default_bitmap_offset;
823 
824 	} else if (mddev->pers == NULL) {
825 		/* Insist on good event counter while assembling */
826 		++ev1;
827 		if (ev1 < mddev->events)
828 			return -EINVAL;
829 	} else if (mddev->bitmap) {
830 		/* if adding to array with a bitmap, then we can accept an
831 		 * older device ... but not too old.
832 		 */
833 		if (ev1 < mddev->bitmap->events_cleared)
834 			return 0;
835 	} else {
836 		if (ev1 < mddev->events)
837 			/* just a hot-add of a new device, leave raid_disk at -1 */
838 			return 0;
839 	}
840 
841 	if (mddev->level != LEVEL_MULTIPATH) {
842 		desc = sb->disks + rdev->desc_nr;
843 
844 		if (desc->state & (1<<MD_DISK_FAULTY))
845 			set_bit(Faulty, &rdev->flags);
846 		else if (desc->state & (1<<MD_DISK_SYNC) /* &&
847 			    desc->raid_disk < mddev->raid_disks */) {
848 			set_bit(In_sync, &rdev->flags);
849 			rdev->raid_disk = desc->raid_disk;
850 		}
851 		if (desc->state & (1<<MD_DISK_WRITEMOSTLY))
852 			set_bit(WriteMostly, &rdev->flags);
853 	} else /* MULTIPATH are always insync */
854 		set_bit(In_sync, &rdev->flags);
855 	return 0;
856 }
857 
858 /*
859  * sync_super for 0.90.0
860  */
861 static void super_90_sync(mddev_t *mddev, mdk_rdev_t *rdev)
862 {
863 	mdp_super_t *sb;
864 	struct list_head *tmp;
865 	mdk_rdev_t *rdev2;
866 	int next_spare = mddev->raid_disks;
867 
868 
869 	/* make rdev->sb match mddev data..
870 	 *
871 	 * 1/ zero out disks
872 	 * 2/ Add info for each disk, keeping track of highest desc_nr (next_spare);
873 	 * 3/ any empty disks < next_spare become removed
874 	 *
875 	 * disks[0] gets initialised to REMOVED because
876 	 * we cannot be sure from other fields if it has
877 	 * been initialised or not.
878 	 */
879 	int i;
880 	int active=0, working=0,failed=0,spare=0,nr_disks=0;
881 
882 	rdev->sb_size = MD_SB_BYTES;
883 
884 	sb = (mdp_super_t*)page_address(rdev->sb_page);
885 
886 	memset(sb, 0, sizeof(*sb));
887 
888 	sb->md_magic = MD_SB_MAGIC;
889 	sb->major_version = mddev->major_version;
890 	sb->patch_version = mddev->patch_version;
891 	sb->gvalid_words  = 0; /* ignored */
892 	memcpy(&sb->set_uuid0, mddev->uuid+0, 4);
893 	memcpy(&sb->set_uuid1, mddev->uuid+4, 4);
894 	memcpy(&sb->set_uuid2, mddev->uuid+8, 4);
895 	memcpy(&sb->set_uuid3, mddev->uuid+12,4);
896 
897 	sb->ctime = mddev->ctime;
898 	sb->level = mddev->level;
899 	sb->size  = mddev->size;
900 	sb->raid_disks = mddev->raid_disks;
901 	sb->md_minor = mddev->md_minor;
902 	sb->not_persistent = 0;
903 	sb->utime = mddev->utime;
904 	sb->state = 0;
905 	sb->events_hi = (mddev->events>>32);
906 	sb->events_lo = (u32)mddev->events;
907 
908 	if (mddev->reshape_position == MaxSector)
909 		sb->minor_version = 90;
910 	else {
911 		sb->minor_version = 91;
912 		sb->reshape_position = mddev->reshape_position;
913 		sb->new_level = mddev->new_level;
914 		sb->delta_disks = mddev->delta_disks;
915 		sb->new_layout = mddev->new_layout;
916 		sb->new_chunk = mddev->new_chunk;
917 	}
918 	mddev->minor_version = sb->minor_version;
919 	if (mddev->in_sync)
920 	{
921 		sb->recovery_cp = mddev->recovery_cp;
922 		sb->cp_events_hi = (mddev->events>>32);
923 		sb->cp_events_lo = (u32)mddev->events;
924 		if (mddev->recovery_cp == MaxSector)
925 			sb->state = (1<< MD_SB_CLEAN);
926 	} else
927 		sb->recovery_cp = 0;
928 
929 	sb->layout = mddev->layout;
930 	sb->chunk_size = mddev->chunk_size;
931 
932 	if (mddev->bitmap && mddev->bitmap_file == NULL)
933 		sb->state |= (1<<MD_SB_BITMAP_PRESENT);
934 
935 	sb->disks[0].state = (1<<MD_DISK_REMOVED);
936 	rdev_for_each(rdev2, tmp, mddev) {
937 		mdp_disk_t *d;
938 		int desc_nr;
939 		if (rdev2->raid_disk >= 0 && test_bit(In_sync, &rdev2->flags)
940 		    && !test_bit(Faulty, &rdev2->flags))
941 			desc_nr = rdev2->raid_disk;
942 		else
943 			desc_nr = next_spare++;
944 		rdev2->desc_nr = desc_nr;
945 		d = &sb->disks[rdev2->desc_nr];
946 		nr_disks++;
947 		d->number = rdev2->desc_nr;
948 		d->major = MAJOR(rdev2->bdev->bd_dev);
949 		d->minor = MINOR(rdev2->bdev->bd_dev);
950 		if (rdev2->raid_disk >= 0 && test_bit(In_sync, &rdev2->flags)
951 		    && !test_bit(Faulty, &rdev2->flags))
952 			d->raid_disk = rdev2->raid_disk;
953 		else
954 			d->raid_disk = rdev2->desc_nr; /* compatibility */
955 		if (test_bit(Faulty, &rdev2->flags))
956 			d->state = (1<<MD_DISK_FAULTY);
957 		else if (test_bit(In_sync, &rdev2->flags)) {
958 			d->state = (1<<MD_DISK_ACTIVE);
959 			d->state |= (1<<MD_DISK_SYNC);
960 			active++;
961 			working++;
962 		} else {
963 			d->state = 0;
964 			spare++;
965 			working++;
966 		}
967 		if (test_bit(WriteMostly, &rdev2->flags))
968 			d->state |= (1<<MD_DISK_WRITEMOSTLY);
969 	}
970 	/* now set the "removed" and "faulty" bits on any missing devices */
971 	for (i=0 ; i < mddev->raid_disks ; i++) {
972 		mdp_disk_t *d = &sb->disks[i];
973 		if (d->state == 0 && d->number == 0) {
974 			d->number = i;
975 			d->raid_disk = i;
976 			d->state = (1<<MD_DISK_REMOVED);
977 			d->state |= (1<<MD_DISK_FAULTY);
978 			failed++;
979 		}
980 	}
981 	sb->nr_disks = nr_disks;
982 	sb->active_disks = active;
983 	sb->working_disks = working;
984 	sb->failed_disks = failed;
985 	sb->spare_disks = spare;
986 
987 	sb->this_disk = sb->disks[rdev->desc_nr];
988 	sb->sb_csum = calc_sb_csum(sb);
989 }
990 
991 /*
992  * rdev_size_change for 0.90.0
993  */
994 static unsigned long long
995 super_90_rdev_size_change(mdk_rdev_t *rdev, sector_t num_sectors)
996 {
997 	if (num_sectors && num_sectors < rdev->mddev->size * 2)
998 		return 0; /* component must fit device */
999 	if (rdev->mddev->bitmap_offset)
1000 		return 0; /* can't move bitmap */
1001 	rdev->sb_start = calc_dev_sboffset(rdev->bdev);
1002 	if (!num_sectors || num_sectors > rdev->sb_start)
1003 		num_sectors = rdev->sb_start;
1004 	md_super_write(rdev->mddev, rdev, rdev->sb_start, rdev->sb_size,
1005 		       rdev->sb_page);
1006 	md_super_wait(rdev->mddev);
1007 	return num_sectors / 2; /* kB for sysfs */
1008 }
1009 
1010 
1011 /*
1012  * version 1 superblock
1013  */
1014 
1015 static __le32 calc_sb_1_csum(struct mdp_superblock_1 * sb)
1016 {
1017 	__le32 disk_csum;
1018 	u32 csum;
1019 	unsigned long long newcsum;
1020 	int size = 256 + le32_to_cpu(sb->max_dev)*2;
1021 	__le32 *isuper = (__le32*)sb;
1022 	int i;
1023 
1024 	disk_csum = sb->sb_csum;
1025 	sb->sb_csum = 0;
1026 	newcsum = 0;
1027 	for (i=0; size>=4; size -= 4 )
1028 		newcsum += le32_to_cpu(*isuper++);
1029 
1030 	if (size == 2)
1031 		newcsum += le16_to_cpu(*(__le16*) isuper);
1032 
1033 	csum = (newcsum & 0xffffffff) + (newcsum >> 32);
1034 	sb->sb_csum = disk_csum;
1035 	return cpu_to_le32(csum);
1036 }
1037 
1038 static int super_1_load(mdk_rdev_t *rdev, mdk_rdev_t *refdev, int minor_version)
1039 {
1040 	struct mdp_superblock_1 *sb;
1041 	int ret;
1042 	sector_t sb_start;
1043 	char b[BDEVNAME_SIZE], b2[BDEVNAME_SIZE];
1044 	int bmask;
1045 
1046 	/*
1047 	 * Calculate the position of the superblock in 512byte sectors.
1048 	 * It is always aligned to a 4K boundary and
1049 	 * depeding on minor_version, it can be:
1050 	 * 0: At least 8K, but less than 12K, from end of device
1051 	 * 1: At start of device
1052 	 * 2: 4K from start of device.
1053 	 */
1054 	switch(minor_version) {
1055 	case 0:
1056 		sb_start = rdev->bdev->bd_inode->i_size >> 9;
1057 		sb_start -= 8*2;
1058 		sb_start &= ~(sector_t)(4*2-1);
1059 		break;
1060 	case 1:
1061 		sb_start = 0;
1062 		break;
1063 	case 2:
1064 		sb_start = 8;
1065 		break;
1066 	default:
1067 		return -EINVAL;
1068 	}
1069 	rdev->sb_start = sb_start;
1070 
1071 	/* superblock is rarely larger than 1K, but it can be larger,
1072 	 * and it is safe to read 4k, so we do that
1073 	 */
1074 	ret = read_disk_sb(rdev, 4096);
1075 	if (ret) return ret;
1076 
1077 
1078 	sb = (struct mdp_superblock_1*)page_address(rdev->sb_page);
1079 
1080 	if (sb->magic != cpu_to_le32(MD_SB_MAGIC) ||
1081 	    sb->major_version != cpu_to_le32(1) ||
1082 	    le32_to_cpu(sb->max_dev) > (4096-256)/2 ||
1083 	    le64_to_cpu(sb->super_offset) != rdev->sb_start ||
1084 	    (le32_to_cpu(sb->feature_map) & ~MD_FEATURE_ALL) != 0)
1085 		return -EINVAL;
1086 
1087 	if (calc_sb_1_csum(sb) != sb->sb_csum) {
1088 		printk("md: invalid superblock checksum on %s\n",
1089 			bdevname(rdev->bdev,b));
1090 		return -EINVAL;
1091 	}
1092 	if (le64_to_cpu(sb->data_size) < 10) {
1093 		printk("md: data_size too small on %s\n",
1094 		       bdevname(rdev->bdev,b));
1095 		return -EINVAL;
1096 	}
1097 	if ((le32_to_cpu(sb->feature_map) & MD_FEATURE_BITMAP_OFFSET)) {
1098 		if (sb->level != cpu_to_le32(1) &&
1099 		    sb->level != cpu_to_le32(4) &&
1100 		    sb->level != cpu_to_le32(5) &&
1101 		    sb->level != cpu_to_le32(6) &&
1102 		    sb->level != cpu_to_le32(10)) {
1103 			printk(KERN_WARNING
1104 			       "md: bitmaps not supported for this level.\n");
1105 			return -EINVAL;
1106 		}
1107 	}
1108 
1109 	rdev->preferred_minor = 0xffff;
1110 	rdev->data_offset = le64_to_cpu(sb->data_offset);
1111 	atomic_set(&rdev->corrected_errors, le32_to_cpu(sb->cnt_corrected_read));
1112 
1113 	rdev->sb_size = le32_to_cpu(sb->max_dev) * 2 + 256;
1114 	bmask = queue_hardsect_size(rdev->bdev->bd_disk->queue)-1;
1115 	if (rdev->sb_size & bmask)
1116 		rdev->sb_size = (rdev->sb_size | bmask) + 1;
1117 
1118 	if (minor_version
1119 	    && rdev->data_offset < sb_start + (rdev->sb_size/512))
1120 		return -EINVAL;
1121 
1122 	if (sb->level == cpu_to_le32(LEVEL_MULTIPATH))
1123 		rdev->desc_nr = -1;
1124 	else
1125 		rdev->desc_nr = le32_to_cpu(sb->dev_number);
1126 
1127 	if (!refdev) {
1128 		ret = 1;
1129 	} else {
1130 		__u64 ev1, ev2;
1131 		struct mdp_superblock_1 *refsb =
1132 			(struct mdp_superblock_1*)page_address(refdev->sb_page);
1133 
1134 		if (memcmp(sb->set_uuid, refsb->set_uuid, 16) != 0 ||
1135 		    sb->level != refsb->level ||
1136 		    sb->layout != refsb->layout ||
1137 		    sb->chunksize != refsb->chunksize) {
1138 			printk(KERN_WARNING "md: %s has strangely different"
1139 				" superblock to %s\n",
1140 				bdevname(rdev->bdev,b),
1141 				bdevname(refdev->bdev,b2));
1142 			return -EINVAL;
1143 		}
1144 		ev1 = le64_to_cpu(sb->events);
1145 		ev2 = le64_to_cpu(refsb->events);
1146 
1147 		if (ev1 > ev2)
1148 			ret = 1;
1149 		else
1150 			ret = 0;
1151 	}
1152 	if (minor_version)
1153 		rdev->size = ((rdev->bdev->bd_inode->i_size>>9) - le64_to_cpu(sb->data_offset)) / 2;
1154 	else
1155 		rdev->size = rdev->sb_start / 2;
1156 	if (rdev->size < le64_to_cpu(sb->data_size)/2)
1157 		return -EINVAL;
1158 	rdev->size = le64_to_cpu(sb->data_size)/2;
1159 	if (le32_to_cpu(sb->chunksize))
1160 		rdev->size &= ~((sector_t)le32_to_cpu(sb->chunksize)/2 - 1);
1161 
1162 	if (le64_to_cpu(sb->size) > rdev->size*2)
1163 		return -EINVAL;
1164 	return ret;
1165 }
1166 
1167 static int super_1_validate(mddev_t *mddev, mdk_rdev_t *rdev)
1168 {
1169 	struct mdp_superblock_1 *sb = (struct mdp_superblock_1*)page_address(rdev->sb_page);
1170 	__u64 ev1 = le64_to_cpu(sb->events);
1171 
1172 	rdev->raid_disk = -1;
1173 	clear_bit(Faulty, &rdev->flags);
1174 	clear_bit(In_sync, &rdev->flags);
1175 	clear_bit(WriteMostly, &rdev->flags);
1176 	clear_bit(BarriersNotsupp, &rdev->flags);
1177 
1178 	if (mddev->raid_disks == 0) {
1179 		mddev->major_version = 1;
1180 		mddev->patch_version = 0;
1181 		mddev->external = 0;
1182 		mddev->chunk_size = le32_to_cpu(sb->chunksize) << 9;
1183 		mddev->ctime = le64_to_cpu(sb->ctime) & ((1ULL << 32)-1);
1184 		mddev->utime = le64_to_cpu(sb->utime) & ((1ULL << 32)-1);
1185 		mddev->level = le32_to_cpu(sb->level);
1186 		mddev->clevel[0] = 0;
1187 		mddev->layout = le32_to_cpu(sb->layout);
1188 		mddev->raid_disks = le32_to_cpu(sb->raid_disks);
1189 		mddev->size = le64_to_cpu(sb->size)/2;
1190 		mddev->events = ev1;
1191 		mddev->bitmap_offset = 0;
1192 		mddev->default_bitmap_offset = 1024 >> 9;
1193 
1194 		mddev->recovery_cp = le64_to_cpu(sb->resync_offset);
1195 		memcpy(mddev->uuid, sb->set_uuid, 16);
1196 
1197 		mddev->max_disks =  (4096-256)/2;
1198 
1199 		if ((le32_to_cpu(sb->feature_map) & MD_FEATURE_BITMAP_OFFSET) &&
1200 		    mddev->bitmap_file == NULL )
1201 			mddev->bitmap_offset = (__s32)le32_to_cpu(sb->bitmap_offset);
1202 
1203 		if ((le32_to_cpu(sb->feature_map) & MD_FEATURE_RESHAPE_ACTIVE)) {
1204 			mddev->reshape_position = le64_to_cpu(sb->reshape_position);
1205 			mddev->delta_disks = le32_to_cpu(sb->delta_disks);
1206 			mddev->new_level = le32_to_cpu(sb->new_level);
1207 			mddev->new_layout = le32_to_cpu(sb->new_layout);
1208 			mddev->new_chunk = le32_to_cpu(sb->new_chunk)<<9;
1209 		} else {
1210 			mddev->reshape_position = MaxSector;
1211 			mddev->delta_disks = 0;
1212 			mddev->new_level = mddev->level;
1213 			mddev->new_layout = mddev->layout;
1214 			mddev->new_chunk = mddev->chunk_size;
1215 		}
1216 
1217 	} else if (mddev->pers == NULL) {
1218 		/* Insist of good event counter while assembling */
1219 		++ev1;
1220 		if (ev1 < mddev->events)
1221 			return -EINVAL;
1222 	} else if (mddev->bitmap) {
1223 		/* If adding to array with a bitmap, then we can accept an
1224 		 * older device, but not too old.
1225 		 */
1226 		if (ev1 < mddev->bitmap->events_cleared)
1227 			return 0;
1228 	} else {
1229 		if (ev1 < mddev->events)
1230 			/* just a hot-add of a new device, leave raid_disk at -1 */
1231 			return 0;
1232 	}
1233 	if (mddev->level != LEVEL_MULTIPATH) {
1234 		int role;
1235 		role = le16_to_cpu(sb->dev_roles[rdev->desc_nr]);
1236 		switch(role) {
1237 		case 0xffff: /* spare */
1238 			break;
1239 		case 0xfffe: /* faulty */
1240 			set_bit(Faulty, &rdev->flags);
1241 			break;
1242 		default:
1243 			if ((le32_to_cpu(sb->feature_map) &
1244 			     MD_FEATURE_RECOVERY_OFFSET))
1245 				rdev->recovery_offset = le64_to_cpu(sb->recovery_offset);
1246 			else
1247 				set_bit(In_sync, &rdev->flags);
1248 			rdev->raid_disk = role;
1249 			break;
1250 		}
1251 		if (sb->devflags & WriteMostly1)
1252 			set_bit(WriteMostly, &rdev->flags);
1253 	} else /* MULTIPATH are always insync */
1254 		set_bit(In_sync, &rdev->flags);
1255 
1256 	return 0;
1257 }
1258 
1259 static void super_1_sync(mddev_t *mddev, mdk_rdev_t *rdev)
1260 {
1261 	struct mdp_superblock_1 *sb;
1262 	struct list_head *tmp;
1263 	mdk_rdev_t *rdev2;
1264 	int max_dev, i;
1265 	/* make rdev->sb match mddev and rdev data. */
1266 
1267 	sb = (struct mdp_superblock_1*)page_address(rdev->sb_page);
1268 
1269 	sb->feature_map = 0;
1270 	sb->pad0 = 0;
1271 	sb->recovery_offset = cpu_to_le64(0);
1272 	memset(sb->pad1, 0, sizeof(sb->pad1));
1273 	memset(sb->pad2, 0, sizeof(sb->pad2));
1274 	memset(sb->pad3, 0, sizeof(sb->pad3));
1275 
1276 	sb->utime = cpu_to_le64((__u64)mddev->utime);
1277 	sb->events = cpu_to_le64(mddev->events);
1278 	if (mddev->in_sync)
1279 		sb->resync_offset = cpu_to_le64(mddev->recovery_cp);
1280 	else
1281 		sb->resync_offset = cpu_to_le64(0);
1282 
1283 	sb->cnt_corrected_read = cpu_to_le32(atomic_read(&rdev->corrected_errors));
1284 
1285 	sb->raid_disks = cpu_to_le32(mddev->raid_disks);
1286 	sb->size = cpu_to_le64(mddev->size<<1);
1287 
1288 	if (mddev->bitmap && mddev->bitmap_file == NULL) {
1289 		sb->bitmap_offset = cpu_to_le32((__u32)mddev->bitmap_offset);
1290 		sb->feature_map = cpu_to_le32(MD_FEATURE_BITMAP_OFFSET);
1291 	}
1292 
1293 	if (rdev->raid_disk >= 0 &&
1294 	    !test_bit(In_sync, &rdev->flags) &&
1295 	    rdev->recovery_offset > 0) {
1296 		sb->feature_map |= cpu_to_le32(MD_FEATURE_RECOVERY_OFFSET);
1297 		sb->recovery_offset = cpu_to_le64(rdev->recovery_offset);
1298 	}
1299 
1300 	if (mddev->reshape_position != MaxSector) {
1301 		sb->feature_map |= cpu_to_le32(MD_FEATURE_RESHAPE_ACTIVE);
1302 		sb->reshape_position = cpu_to_le64(mddev->reshape_position);
1303 		sb->new_layout = cpu_to_le32(mddev->new_layout);
1304 		sb->delta_disks = cpu_to_le32(mddev->delta_disks);
1305 		sb->new_level = cpu_to_le32(mddev->new_level);
1306 		sb->new_chunk = cpu_to_le32(mddev->new_chunk>>9);
1307 	}
1308 
1309 	max_dev = 0;
1310 	rdev_for_each(rdev2, tmp, mddev)
1311 		if (rdev2->desc_nr+1 > max_dev)
1312 			max_dev = rdev2->desc_nr+1;
1313 
1314 	if (max_dev > le32_to_cpu(sb->max_dev))
1315 		sb->max_dev = cpu_to_le32(max_dev);
1316 	for (i=0; i<max_dev;i++)
1317 		sb->dev_roles[i] = cpu_to_le16(0xfffe);
1318 
1319 	rdev_for_each(rdev2, tmp, mddev) {
1320 		i = rdev2->desc_nr;
1321 		if (test_bit(Faulty, &rdev2->flags))
1322 			sb->dev_roles[i] = cpu_to_le16(0xfffe);
1323 		else if (test_bit(In_sync, &rdev2->flags))
1324 			sb->dev_roles[i] = cpu_to_le16(rdev2->raid_disk);
1325 		else if (rdev2->raid_disk >= 0 && rdev2->recovery_offset > 0)
1326 			sb->dev_roles[i] = cpu_to_le16(rdev2->raid_disk);
1327 		else
1328 			sb->dev_roles[i] = cpu_to_le16(0xffff);
1329 	}
1330 
1331 	sb->sb_csum = calc_sb_1_csum(sb);
1332 }
1333 
1334 static unsigned long long
1335 super_1_rdev_size_change(mdk_rdev_t *rdev, sector_t num_sectors)
1336 {
1337 	struct mdp_superblock_1 *sb;
1338 	sector_t max_sectors;
1339 	if (num_sectors && num_sectors < rdev->mddev->size * 2)
1340 		return 0; /* component must fit device */
1341 	if (rdev->sb_start < rdev->data_offset) {
1342 		/* minor versions 1 and 2; superblock before data */
1343 		max_sectors = rdev->bdev->bd_inode->i_size >> 9;
1344 		max_sectors -= rdev->data_offset;
1345 		if (!num_sectors || num_sectors > max_sectors)
1346 			num_sectors = max_sectors;
1347 	} else if (rdev->mddev->bitmap_offset) {
1348 		/* minor version 0 with bitmap we can't move */
1349 		return 0;
1350 	} else {
1351 		/* minor version 0; superblock after data */
1352 		sector_t sb_start;
1353 		sb_start = (rdev->bdev->bd_inode->i_size >> 9) - 8*2;
1354 		sb_start &= ~(sector_t)(4*2 - 1);
1355 		max_sectors = rdev->size * 2 + sb_start - rdev->sb_start;
1356 		if (!num_sectors || num_sectors > max_sectors)
1357 			num_sectors = max_sectors;
1358 		rdev->sb_start = sb_start;
1359 	}
1360 	sb = (struct mdp_superblock_1 *) page_address(rdev->sb_page);
1361 	sb->data_size = cpu_to_le64(num_sectors);
1362 	sb->super_offset = rdev->sb_start;
1363 	sb->sb_csum = calc_sb_1_csum(sb);
1364 	md_super_write(rdev->mddev, rdev, rdev->sb_start, rdev->sb_size,
1365 		       rdev->sb_page);
1366 	md_super_wait(rdev->mddev);
1367 	return num_sectors / 2; /* kB for sysfs */
1368 }
1369 
1370 static struct super_type super_types[] = {
1371 	[0] = {
1372 		.name	= "0.90.0",
1373 		.owner	= THIS_MODULE,
1374 		.load_super	    = super_90_load,
1375 		.validate_super	    = super_90_validate,
1376 		.sync_super	    = super_90_sync,
1377 		.rdev_size_change   = super_90_rdev_size_change,
1378 	},
1379 	[1] = {
1380 		.name	= "md-1",
1381 		.owner	= THIS_MODULE,
1382 		.load_super	    = super_1_load,
1383 		.validate_super	    = super_1_validate,
1384 		.sync_super	    = super_1_sync,
1385 		.rdev_size_change   = super_1_rdev_size_change,
1386 	},
1387 };
1388 
1389 static int match_mddev_units(mddev_t *mddev1, mddev_t *mddev2)
1390 {
1391 	mdk_rdev_t *rdev, *rdev2;
1392 
1393 	rcu_read_lock();
1394 	rdev_for_each_rcu(rdev, mddev1)
1395 		rdev_for_each_rcu(rdev2, mddev2)
1396 			if (rdev->bdev->bd_contains ==
1397 			    rdev2->bdev->bd_contains) {
1398 				rcu_read_unlock();
1399 				return 1;
1400 			}
1401 	rcu_read_unlock();
1402 	return 0;
1403 }
1404 
1405 static LIST_HEAD(pending_raid_disks);
1406 
1407 static int bind_rdev_to_array(mdk_rdev_t * rdev, mddev_t * mddev)
1408 {
1409 	char b[BDEVNAME_SIZE];
1410 	struct kobject *ko;
1411 	char *s;
1412 	int err;
1413 
1414 	if (rdev->mddev) {
1415 		MD_BUG();
1416 		return -EINVAL;
1417 	}
1418 
1419 	/* prevent duplicates */
1420 	if (find_rdev(mddev, rdev->bdev->bd_dev))
1421 		return -EEXIST;
1422 
1423 	/* make sure rdev->size exceeds mddev->size */
1424 	if (rdev->size && (mddev->size == 0 || rdev->size < mddev->size)) {
1425 		if (mddev->pers) {
1426 			/* Cannot change size, so fail
1427 			 * If mddev->level <= 0, then we don't care
1428 			 * about aligning sizes (e.g. linear)
1429 			 */
1430 			if (mddev->level > 0)
1431 				return -ENOSPC;
1432 		} else
1433 			mddev->size = rdev->size;
1434 	}
1435 
1436 	/* Verify rdev->desc_nr is unique.
1437 	 * If it is -1, assign a free number, else
1438 	 * check number is not in use
1439 	 */
1440 	if (rdev->desc_nr < 0) {
1441 		int choice = 0;
1442 		if (mddev->pers) choice = mddev->raid_disks;
1443 		while (find_rdev_nr(mddev, choice))
1444 			choice++;
1445 		rdev->desc_nr = choice;
1446 	} else {
1447 		if (find_rdev_nr(mddev, rdev->desc_nr))
1448 			return -EBUSY;
1449 	}
1450 	bdevname(rdev->bdev,b);
1451 	while ( (s=strchr(b, '/')) != NULL)
1452 		*s = '!';
1453 
1454 	rdev->mddev = mddev;
1455 	printk(KERN_INFO "md: bind<%s>\n", b);
1456 
1457 	if ((err = kobject_add(&rdev->kobj, &mddev->kobj, "dev-%s", b)))
1458 		goto fail;
1459 
1460 	ko = &part_to_dev(rdev->bdev->bd_part)->kobj;
1461 	if ((err = sysfs_create_link(&rdev->kobj, ko, "block"))) {
1462 		kobject_del(&rdev->kobj);
1463 		goto fail;
1464 	}
1465 	rdev->sysfs_state = sysfs_get_dirent(rdev->kobj.sd, "state");
1466 
1467 	list_add_rcu(&rdev->same_set, &mddev->disks);
1468 	bd_claim_by_disk(rdev->bdev, rdev->bdev->bd_holder, mddev->gendisk);
1469 	return 0;
1470 
1471  fail:
1472 	printk(KERN_WARNING "md: failed to register dev-%s for %s\n",
1473 	       b, mdname(mddev));
1474 	return err;
1475 }
1476 
1477 static void md_delayed_delete(struct work_struct *ws)
1478 {
1479 	mdk_rdev_t *rdev = container_of(ws, mdk_rdev_t, del_work);
1480 	kobject_del(&rdev->kobj);
1481 	kobject_put(&rdev->kobj);
1482 }
1483 
1484 static void unbind_rdev_from_array(mdk_rdev_t * rdev)
1485 {
1486 	char b[BDEVNAME_SIZE];
1487 	if (!rdev->mddev) {
1488 		MD_BUG();
1489 		return;
1490 	}
1491 	bd_release_from_disk(rdev->bdev, rdev->mddev->gendisk);
1492 	list_del_rcu(&rdev->same_set);
1493 	printk(KERN_INFO "md: unbind<%s>\n", bdevname(rdev->bdev,b));
1494 	rdev->mddev = NULL;
1495 	sysfs_remove_link(&rdev->kobj, "block");
1496 	sysfs_put(rdev->sysfs_state);
1497 	rdev->sysfs_state = NULL;
1498 	/* We need to delay this, otherwise we can deadlock when
1499 	 * writing to 'remove' to "dev/state".  We also need
1500 	 * to delay it due to rcu usage.
1501 	 */
1502 	synchronize_rcu();
1503 	INIT_WORK(&rdev->del_work, md_delayed_delete);
1504 	kobject_get(&rdev->kobj);
1505 	schedule_work(&rdev->del_work);
1506 }
1507 
1508 /*
1509  * prevent the device from being mounted, repartitioned or
1510  * otherwise reused by a RAID array (or any other kernel
1511  * subsystem), by bd_claiming the device.
1512  */
1513 static int lock_rdev(mdk_rdev_t *rdev, dev_t dev, int shared)
1514 {
1515 	int err = 0;
1516 	struct block_device *bdev;
1517 	char b[BDEVNAME_SIZE];
1518 
1519 	bdev = open_by_devnum(dev, FMODE_READ|FMODE_WRITE);
1520 	if (IS_ERR(bdev)) {
1521 		printk(KERN_ERR "md: could not open %s.\n",
1522 			__bdevname(dev, b));
1523 		return PTR_ERR(bdev);
1524 	}
1525 	err = bd_claim(bdev, shared ? (mdk_rdev_t *)lock_rdev : rdev);
1526 	if (err) {
1527 		printk(KERN_ERR "md: could not bd_claim %s.\n",
1528 			bdevname(bdev, b));
1529 		blkdev_put(bdev, FMODE_READ|FMODE_WRITE);
1530 		return err;
1531 	}
1532 	if (!shared)
1533 		set_bit(AllReserved, &rdev->flags);
1534 	rdev->bdev = bdev;
1535 	return err;
1536 }
1537 
1538 static void unlock_rdev(mdk_rdev_t *rdev)
1539 {
1540 	struct block_device *bdev = rdev->bdev;
1541 	rdev->bdev = NULL;
1542 	if (!bdev)
1543 		MD_BUG();
1544 	bd_release(bdev);
1545 	blkdev_put(bdev, FMODE_READ|FMODE_WRITE);
1546 }
1547 
1548 void md_autodetect_dev(dev_t dev);
1549 
1550 static void export_rdev(mdk_rdev_t * rdev)
1551 {
1552 	char b[BDEVNAME_SIZE];
1553 	printk(KERN_INFO "md: export_rdev(%s)\n",
1554 		bdevname(rdev->bdev,b));
1555 	if (rdev->mddev)
1556 		MD_BUG();
1557 	free_disk_sb(rdev);
1558 #ifndef MODULE
1559 	if (test_bit(AutoDetected, &rdev->flags))
1560 		md_autodetect_dev(rdev->bdev->bd_dev);
1561 #endif
1562 	unlock_rdev(rdev);
1563 	kobject_put(&rdev->kobj);
1564 }
1565 
1566 static void kick_rdev_from_array(mdk_rdev_t * rdev)
1567 {
1568 	unbind_rdev_from_array(rdev);
1569 	export_rdev(rdev);
1570 }
1571 
1572 static void export_array(mddev_t *mddev)
1573 {
1574 	struct list_head *tmp;
1575 	mdk_rdev_t *rdev;
1576 
1577 	rdev_for_each(rdev, tmp, mddev) {
1578 		if (!rdev->mddev) {
1579 			MD_BUG();
1580 			continue;
1581 		}
1582 		kick_rdev_from_array(rdev);
1583 	}
1584 	if (!list_empty(&mddev->disks))
1585 		MD_BUG();
1586 	mddev->raid_disks = 0;
1587 	mddev->major_version = 0;
1588 }
1589 
1590 static void print_desc(mdp_disk_t *desc)
1591 {
1592 	printk(" DISK<N:%d,(%d,%d),R:%d,S:%d>\n", desc->number,
1593 		desc->major,desc->minor,desc->raid_disk,desc->state);
1594 }
1595 
1596 static void print_sb(mdp_super_t *sb)
1597 {
1598 	int i;
1599 
1600 	printk(KERN_INFO
1601 		"md:  SB: (V:%d.%d.%d) ID:<%08x.%08x.%08x.%08x> CT:%08x\n",
1602 		sb->major_version, sb->minor_version, sb->patch_version,
1603 		sb->set_uuid0, sb->set_uuid1, sb->set_uuid2, sb->set_uuid3,
1604 		sb->ctime);
1605 	printk(KERN_INFO "md:     L%d S%08d ND:%d RD:%d md%d LO:%d CS:%d\n",
1606 		sb->level, sb->size, sb->nr_disks, sb->raid_disks,
1607 		sb->md_minor, sb->layout, sb->chunk_size);
1608 	printk(KERN_INFO "md:     UT:%08x ST:%d AD:%d WD:%d"
1609 		" FD:%d SD:%d CSUM:%08x E:%08lx\n",
1610 		sb->utime, sb->state, sb->active_disks, sb->working_disks,
1611 		sb->failed_disks, sb->spare_disks,
1612 		sb->sb_csum, (unsigned long)sb->events_lo);
1613 
1614 	printk(KERN_INFO);
1615 	for (i = 0; i < MD_SB_DISKS; i++) {
1616 		mdp_disk_t *desc;
1617 
1618 		desc = sb->disks + i;
1619 		if (desc->number || desc->major || desc->minor ||
1620 		    desc->raid_disk || (desc->state && (desc->state != 4))) {
1621 			printk("     D %2d: ", i);
1622 			print_desc(desc);
1623 		}
1624 	}
1625 	printk(KERN_INFO "md:     THIS: ");
1626 	print_desc(&sb->this_disk);
1627 
1628 }
1629 
1630 static void print_rdev(mdk_rdev_t *rdev)
1631 {
1632 	char b[BDEVNAME_SIZE];
1633 	printk(KERN_INFO "md: rdev %s, SZ:%08llu F:%d S:%d DN:%u\n",
1634 		bdevname(rdev->bdev,b), (unsigned long long)rdev->size,
1635 	        test_bit(Faulty, &rdev->flags), test_bit(In_sync, &rdev->flags),
1636 	        rdev->desc_nr);
1637 	if (rdev->sb_loaded) {
1638 		printk(KERN_INFO "md: rdev superblock:\n");
1639 		print_sb((mdp_super_t*)page_address(rdev->sb_page));
1640 	} else
1641 		printk(KERN_INFO "md: no rdev superblock!\n");
1642 }
1643 
1644 static void md_print_devices(void)
1645 {
1646 	struct list_head *tmp, *tmp2;
1647 	mdk_rdev_t *rdev;
1648 	mddev_t *mddev;
1649 	char b[BDEVNAME_SIZE];
1650 
1651 	printk("\n");
1652 	printk("md:	**********************************\n");
1653 	printk("md:	* <COMPLETE RAID STATE PRINTOUT> *\n");
1654 	printk("md:	**********************************\n");
1655 	for_each_mddev(mddev, tmp) {
1656 
1657 		if (mddev->bitmap)
1658 			bitmap_print_sb(mddev->bitmap);
1659 		else
1660 			printk("%s: ", mdname(mddev));
1661 		rdev_for_each(rdev, tmp2, mddev)
1662 			printk("<%s>", bdevname(rdev->bdev,b));
1663 		printk("\n");
1664 
1665 		rdev_for_each(rdev, tmp2, mddev)
1666 			print_rdev(rdev);
1667 	}
1668 	printk("md:	**********************************\n");
1669 	printk("\n");
1670 }
1671 
1672 
1673 static void sync_sbs(mddev_t * mddev, int nospares)
1674 {
1675 	/* Update each superblock (in-memory image), but
1676 	 * if we are allowed to, skip spares which already
1677 	 * have the right event counter, or have one earlier
1678 	 * (which would mean they aren't being marked as dirty
1679 	 * with the rest of the array)
1680 	 */
1681 	mdk_rdev_t *rdev;
1682 	struct list_head *tmp;
1683 
1684 	rdev_for_each(rdev, tmp, mddev) {
1685 		if (rdev->sb_events == mddev->events ||
1686 		    (nospares &&
1687 		     rdev->raid_disk < 0 &&
1688 		     (rdev->sb_events&1)==0 &&
1689 		     rdev->sb_events+1 == mddev->events)) {
1690 			/* Don't update this superblock */
1691 			rdev->sb_loaded = 2;
1692 		} else {
1693 			super_types[mddev->major_version].
1694 				sync_super(mddev, rdev);
1695 			rdev->sb_loaded = 1;
1696 		}
1697 	}
1698 }
1699 
1700 static void md_update_sb(mddev_t * mddev, int force_change)
1701 {
1702 	struct list_head *tmp;
1703 	mdk_rdev_t *rdev;
1704 	int sync_req;
1705 	int nospares = 0;
1706 
1707 	if (mddev->external)
1708 		return;
1709 repeat:
1710 	spin_lock_irq(&mddev->write_lock);
1711 
1712 	set_bit(MD_CHANGE_PENDING, &mddev->flags);
1713 	if (test_and_clear_bit(MD_CHANGE_DEVS, &mddev->flags))
1714 		force_change = 1;
1715 	if (test_and_clear_bit(MD_CHANGE_CLEAN, &mddev->flags))
1716 		/* just a clean<-> dirty transition, possibly leave spares alone,
1717 		 * though if events isn't the right even/odd, we will have to do
1718 		 * spares after all
1719 		 */
1720 		nospares = 1;
1721 	if (force_change)
1722 		nospares = 0;
1723 	if (mddev->degraded)
1724 		/* If the array is degraded, then skipping spares is both
1725 		 * dangerous and fairly pointless.
1726 		 * Dangerous because a device that was removed from the array
1727 		 * might have a event_count that still looks up-to-date,
1728 		 * so it can be re-added without a resync.
1729 		 * Pointless because if there are any spares to skip,
1730 		 * then a recovery will happen and soon that array won't
1731 		 * be degraded any more and the spare can go back to sleep then.
1732 		 */
1733 		nospares = 0;
1734 
1735 	sync_req = mddev->in_sync;
1736 	mddev->utime = get_seconds();
1737 
1738 	/* If this is just a dirty<->clean transition, and the array is clean
1739 	 * and 'events' is odd, we can roll back to the previous clean state */
1740 	if (nospares
1741 	    && (mddev->in_sync && mddev->recovery_cp == MaxSector)
1742 	    && (mddev->events & 1)
1743 	    && mddev->events != 1)
1744 		mddev->events--;
1745 	else {
1746 		/* otherwise we have to go forward and ... */
1747 		mddev->events ++;
1748 		if (!mddev->in_sync || mddev->recovery_cp != MaxSector) { /* not clean */
1749 			/* .. if the array isn't clean, insist on an odd 'events' */
1750 			if ((mddev->events&1)==0) {
1751 				mddev->events++;
1752 				nospares = 0;
1753 			}
1754 		} else {
1755 			/* otherwise insist on an even 'events' (for clean states) */
1756 			if ((mddev->events&1)) {
1757 				mddev->events++;
1758 				nospares = 0;
1759 			}
1760 		}
1761 	}
1762 
1763 	if (!mddev->events) {
1764 		/*
1765 		 * oops, this 64-bit counter should never wrap.
1766 		 * Either we are in around ~1 trillion A.C., assuming
1767 		 * 1 reboot per second, or we have a bug:
1768 		 */
1769 		MD_BUG();
1770 		mddev->events --;
1771 	}
1772 
1773 	/*
1774 	 * do not write anything to disk if using
1775 	 * nonpersistent superblocks
1776 	 */
1777 	if (!mddev->persistent) {
1778 		if (!mddev->external)
1779 			clear_bit(MD_CHANGE_PENDING, &mddev->flags);
1780 
1781 		spin_unlock_irq(&mddev->write_lock);
1782 		wake_up(&mddev->sb_wait);
1783 		return;
1784 	}
1785 	sync_sbs(mddev, nospares);
1786 	spin_unlock_irq(&mddev->write_lock);
1787 
1788 	dprintk(KERN_INFO
1789 		"md: updating %s RAID superblock on device (in sync %d)\n",
1790 		mdname(mddev),mddev->in_sync);
1791 
1792 	bitmap_update_sb(mddev->bitmap);
1793 	rdev_for_each(rdev, tmp, mddev) {
1794 		char b[BDEVNAME_SIZE];
1795 		dprintk(KERN_INFO "md: ");
1796 		if (rdev->sb_loaded != 1)
1797 			continue; /* no noise on spare devices */
1798 		if (test_bit(Faulty, &rdev->flags))
1799 			dprintk("(skipping faulty ");
1800 
1801 		dprintk("%s ", bdevname(rdev->bdev,b));
1802 		if (!test_bit(Faulty, &rdev->flags)) {
1803 			md_super_write(mddev,rdev,
1804 				       rdev->sb_start, rdev->sb_size,
1805 				       rdev->sb_page);
1806 			dprintk(KERN_INFO "(write) %s's sb offset: %llu\n",
1807 				bdevname(rdev->bdev,b),
1808 				(unsigned long long)rdev->sb_start);
1809 			rdev->sb_events = mddev->events;
1810 
1811 		} else
1812 			dprintk(")\n");
1813 		if (mddev->level == LEVEL_MULTIPATH)
1814 			/* only need to write one superblock... */
1815 			break;
1816 	}
1817 	md_super_wait(mddev);
1818 	/* if there was a failure, MD_CHANGE_DEVS was set, and we re-write super */
1819 
1820 	spin_lock_irq(&mddev->write_lock);
1821 	if (mddev->in_sync != sync_req ||
1822 	    test_bit(MD_CHANGE_DEVS, &mddev->flags)) {
1823 		/* have to write it out again */
1824 		spin_unlock_irq(&mddev->write_lock);
1825 		goto repeat;
1826 	}
1827 	clear_bit(MD_CHANGE_PENDING, &mddev->flags);
1828 	spin_unlock_irq(&mddev->write_lock);
1829 	wake_up(&mddev->sb_wait);
1830 
1831 }
1832 
1833 /* words written to sysfs files may, or may not, be \n terminated.
1834  * We want to accept with case. For this we use cmd_match.
1835  */
1836 static int cmd_match(const char *cmd, const char *str)
1837 {
1838 	/* See if cmd, written into a sysfs file, matches
1839 	 * str.  They must either be the same, or cmd can
1840 	 * have a trailing newline
1841 	 */
1842 	while (*cmd && *str && *cmd == *str) {
1843 		cmd++;
1844 		str++;
1845 	}
1846 	if (*cmd == '\n')
1847 		cmd++;
1848 	if (*str || *cmd)
1849 		return 0;
1850 	return 1;
1851 }
1852 
1853 struct rdev_sysfs_entry {
1854 	struct attribute attr;
1855 	ssize_t (*show)(mdk_rdev_t *, char *);
1856 	ssize_t (*store)(mdk_rdev_t *, const char *, size_t);
1857 };
1858 
1859 static ssize_t
1860 state_show(mdk_rdev_t *rdev, char *page)
1861 {
1862 	char *sep = "";
1863 	size_t len = 0;
1864 
1865 	if (test_bit(Faulty, &rdev->flags)) {
1866 		len+= sprintf(page+len, "%sfaulty",sep);
1867 		sep = ",";
1868 	}
1869 	if (test_bit(In_sync, &rdev->flags)) {
1870 		len += sprintf(page+len, "%sin_sync",sep);
1871 		sep = ",";
1872 	}
1873 	if (test_bit(WriteMostly, &rdev->flags)) {
1874 		len += sprintf(page+len, "%swrite_mostly",sep);
1875 		sep = ",";
1876 	}
1877 	if (test_bit(Blocked, &rdev->flags)) {
1878 		len += sprintf(page+len, "%sblocked", sep);
1879 		sep = ",";
1880 	}
1881 	if (!test_bit(Faulty, &rdev->flags) &&
1882 	    !test_bit(In_sync, &rdev->flags)) {
1883 		len += sprintf(page+len, "%sspare", sep);
1884 		sep = ",";
1885 	}
1886 	return len+sprintf(page+len, "\n");
1887 }
1888 
1889 static ssize_t
1890 state_store(mdk_rdev_t *rdev, const char *buf, size_t len)
1891 {
1892 	/* can write
1893 	 *  faulty  - simulates and error
1894 	 *  remove  - disconnects the device
1895 	 *  writemostly - sets write_mostly
1896 	 *  -writemostly - clears write_mostly
1897 	 *  blocked - sets the Blocked flag
1898 	 *  -blocked - clears the Blocked flag
1899 	 */
1900 	int err = -EINVAL;
1901 	if (cmd_match(buf, "faulty") && rdev->mddev->pers) {
1902 		md_error(rdev->mddev, rdev);
1903 		err = 0;
1904 	} else if (cmd_match(buf, "remove")) {
1905 		if (rdev->raid_disk >= 0)
1906 			err = -EBUSY;
1907 		else {
1908 			mddev_t *mddev = rdev->mddev;
1909 			kick_rdev_from_array(rdev);
1910 			if (mddev->pers)
1911 				md_update_sb(mddev, 1);
1912 			md_new_event(mddev);
1913 			err = 0;
1914 		}
1915 	} else if (cmd_match(buf, "writemostly")) {
1916 		set_bit(WriteMostly, &rdev->flags);
1917 		err = 0;
1918 	} else if (cmd_match(buf, "-writemostly")) {
1919 		clear_bit(WriteMostly, &rdev->flags);
1920 		err = 0;
1921 	} else if (cmd_match(buf, "blocked")) {
1922 		set_bit(Blocked, &rdev->flags);
1923 		err = 0;
1924 	} else if (cmd_match(buf, "-blocked")) {
1925 		clear_bit(Blocked, &rdev->flags);
1926 		wake_up(&rdev->blocked_wait);
1927 		set_bit(MD_RECOVERY_NEEDED, &rdev->mddev->recovery);
1928 		md_wakeup_thread(rdev->mddev->thread);
1929 
1930 		err = 0;
1931 	}
1932 	if (!err && rdev->sysfs_state)
1933 		sysfs_notify_dirent(rdev->sysfs_state);
1934 	return err ? err : len;
1935 }
1936 static struct rdev_sysfs_entry rdev_state =
1937 __ATTR(state, S_IRUGO|S_IWUSR, state_show, state_store);
1938 
1939 static ssize_t
1940 errors_show(mdk_rdev_t *rdev, char *page)
1941 {
1942 	return sprintf(page, "%d\n", atomic_read(&rdev->corrected_errors));
1943 }
1944 
1945 static ssize_t
1946 errors_store(mdk_rdev_t *rdev, const char *buf, size_t len)
1947 {
1948 	char *e;
1949 	unsigned long n = simple_strtoul(buf, &e, 10);
1950 	if (*buf && (*e == 0 || *e == '\n')) {
1951 		atomic_set(&rdev->corrected_errors, n);
1952 		return len;
1953 	}
1954 	return -EINVAL;
1955 }
1956 static struct rdev_sysfs_entry rdev_errors =
1957 __ATTR(errors, S_IRUGO|S_IWUSR, errors_show, errors_store);
1958 
1959 static ssize_t
1960 slot_show(mdk_rdev_t *rdev, char *page)
1961 {
1962 	if (rdev->raid_disk < 0)
1963 		return sprintf(page, "none\n");
1964 	else
1965 		return sprintf(page, "%d\n", rdev->raid_disk);
1966 }
1967 
1968 static ssize_t
1969 slot_store(mdk_rdev_t *rdev, const char *buf, size_t len)
1970 {
1971 	char *e;
1972 	int err;
1973 	char nm[20];
1974 	int slot = simple_strtoul(buf, &e, 10);
1975 	if (strncmp(buf, "none", 4)==0)
1976 		slot = -1;
1977 	else if (e==buf || (*e && *e!= '\n'))
1978 		return -EINVAL;
1979 	if (rdev->mddev->pers && slot == -1) {
1980 		/* Setting 'slot' on an active array requires also
1981 		 * updating the 'rd%d' link, and communicating
1982 		 * with the personality with ->hot_*_disk.
1983 		 * For now we only support removing
1984 		 * failed/spare devices.  This normally happens automatically,
1985 		 * but not when the metadata is externally managed.
1986 		 */
1987 		if (rdev->raid_disk == -1)
1988 			return -EEXIST;
1989 		/* personality does all needed checks */
1990 		if (rdev->mddev->pers->hot_add_disk == NULL)
1991 			return -EINVAL;
1992 		err = rdev->mddev->pers->
1993 			hot_remove_disk(rdev->mddev, rdev->raid_disk);
1994 		if (err)
1995 			return err;
1996 		sprintf(nm, "rd%d", rdev->raid_disk);
1997 		sysfs_remove_link(&rdev->mddev->kobj, nm);
1998 		set_bit(MD_RECOVERY_NEEDED, &rdev->mddev->recovery);
1999 		md_wakeup_thread(rdev->mddev->thread);
2000 	} else if (rdev->mddev->pers) {
2001 		mdk_rdev_t *rdev2;
2002 		struct list_head *tmp;
2003 		/* Activating a spare .. or possibly reactivating
2004 		 * if we every get bitmaps working here.
2005 		 */
2006 
2007 		if (rdev->raid_disk != -1)
2008 			return -EBUSY;
2009 
2010 		if (rdev->mddev->pers->hot_add_disk == NULL)
2011 			return -EINVAL;
2012 
2013 		rdev_for_each(rdev2, tmp, rdev->mddev)
2014 			if (rdev2->raid_disk == slot)
2015 				return -EEXIST;
2016 
2017 		rdev->raid_disk = slot;
2018 		if (test_bit(In_sync, &rdev->flags))
2019 			rdev->saved_raid_disk = slot;
2020 		else
2021 			rdev->saved_raid_disk = -1;
2022 		err = rdev->mddev->pers->
2023 			hot_add_disk(rdev->mddev, rdev);
2024 		if (err) {
2025 			rdev->raid_disk = -1;
2026 			return err;
2027 		} else
2028 			sysfs_notify_dirent(rdev->sysfs_state);
2029 		sprintf(nm, "rd%d", rdev->raid_disk);
2030 		if (sysfs_create_link(&rdev->mddev->kobj, &rdev->kobj, nm))
2031 			printk(KERN_WARNING
2032 			       "md: cannot register "
2033 			       "%s for %s\n",
2034 			       nm, mdname(rdev->mddev));
2035 
2036 		/* don't wakeup anyone, leave that to userspace. */
2037 	} else {
2038 		if (slot >= rdev->mddev->raid_disks)
2039 			return -ENOSPC;
2040 		rdev->raid_disk = slot;
2041 		/* assume it is working */
2042 		clear_bit(Faulty, &rdev->flags);
2043 		clear_bit(WriteMostly, &rdev->flags);
2044 		set_bit(In_sync, &rdev->flags);
2045 		sysfs_notify_dirent(rdev->sysfs_state);
2046 	}
2047 	return len;
2048 }
2049 
2050 
2051 static struct rdev_sysfs_entry rdev_slot =
2052 __ATTR(slot, S_IRUGO|S_IWUSR, slot_show, slot_store);
2053 
2054 static ssize_t
2055 offset_show(mdk_rdev_t *rdev, char *page)
2056 {
2057 	return sprintf(page, "%llu\n", (unsigned long long)rdev->data_offset);
2058 }
2059 
2060 static ssize_t
2061 offset_store(mdk_rdev_t *rdev, const char *buf, size_t len)
2062 {
2063 	char *e;
2064 	unsigned long long offset = simple_strtoull(buf, &e, 10);
2065 	if (e==buf || (*e && *e != '\n'))
2066 		return -EINVAL;
2067 	if (rdev->mddev->pers && rdev->raid_disk >= 0)
2068 		return -EBUSY;
2069 	if (rdev->size && rdev->mddev->external)
2070 		/* Must set offset before size, so overlap checks
2071 		 * can be sane */
2072 		return -EBUSY;
2073 	rdev->data_offset = offset;
2074 	return len;
2075 }
2076 
2077 static struct rdev_sysfs_entry rdev_offset =
2078 __ATTR(offset, S_IRUGO|S_IWUSR, offset_show, offset_store);
2079 
2080 static ssize_t
2081 rdev_size_show(mdk_rdev_t *rdev, char *page)
2082 {
2083 	return sprintf(page, "%llu\n", (unsigned long long)rdev->size);
2084 }
2085 
2086 static int overlaps(sector_t s1, sector_t l1, sector_t s2, sector_t l2)
2087 {
2088 	/* check if two start/length pairs overlap */
2089 	if (s1+l1 <= s2)
2090 		return 0;
2091 	if (s2+l2 <= s1)
2092 		return 0;
2093 	return 1;
2094 }
2095 
2096 static ssize_t
2097 rdev_size_store(mdk_rdev_t *rdev, const char *buf, size_t len)
2098 {
2099 	unsigned long long size;
2100 	unsigned long long oldsize = rdev->size;
2101 	mddev_t *my_mddev = rdev->mddev;
2102 
2103 	if (strict_strtoull(buf, 10, &size) < 0)
2104 		return -EINVAL;
2105 	if (my_mddev->pers && rdev->raid_disk >= 0) {
2106 		if (my_mddev->persistent) {
2107 			size = super_types[my_mddev->major_version].
2108 				rdev_size_change(rdev, size * 2);
2109 			if (!size)
2110 				return -EBUSY;
2111 		} else if (!size) {
2112 			size = (rdev->bdev->bd_inode->i_size >> 10);
2113 			size -= rdev->data_offset/2;
2114 		}
2115 	}
2116 	if (size < my_mddev->size)
2117 		return -EINVAL; /* component must fit device */
2118 
2119 	rdev->size = size;
2120 	if (size > oldsize && my_mddev->external) {
2121 		/* need to check that all other rdevs with the same ->bdev
2122 		 * do not overlap.  We need to unlock the mddev to avoid
2123 		 * a deadlock.  We have already changed rdev->size, and if
2124 		 * we have to change it back, we will have the lock again.
2125 		 */
2126 		mddev_t *mddev;
2127 		int overlap = 0;
2128 		struct list_head *tmp, *tmp2;
2129 
2130 		mddev_unlock(my_mddev);
2131 		for_each_mddev(mddev, tmp) {
2132 			mdk_rdev_t *rdev2;
2133 
2134 			mddev_lock(mddev);
2135 			rdev_for_each(rdev2, tmp2, mddev)
2136 				if (test_bit(AllReserved, &rdev2->flags) ||
2137 				    (rdev->bdev == rdev2->bdev &&
2138 				     rdev != rdev2 &&
2139 				     overlaps(rdev->data_offset, rdev->size * 2,
2140 					      rdev2->data_offset,
2141 					      rdev2->size * 2))) {
2142 					overlap = 1;
2143 					break;
2144 				}
2145 			mddev_unlock(mddev);
2146 			if (overlap) {
2147 				mddev_put(mddev);
2148 				break;
2149 			}
2150 		}
2151 		mddev_lock(my_mddev);
2152 		if (overlap) {
2153 			/* Someone else could have slipped in a size
2154 			 * change here, but doing so is just silly.
2155 			 * We put oldsize back because we *know* it is
2156 			 * safe, and trust userspace not to race with
2157 			 * itself
2158 			 */
2159 			rdev->size = oldsize;
2160 			return -EBUSY;
2161 		}
2162 	}
2163 	return len;
2164 }
2165 
2166 static struct rdev_sysfs_entry rdev_size =
2167 __ATTR(size, S_IRUGO|S_IWUSR, rdev_size_show, rdev_size_store);
2168 
2169 static struct attribute *rdev_default_attrs[] = {
2170 	&rdev_state.attr,
2171 	&rdev_errors.attr,
2172 	&rdev_slot.attr,
2173 	&rdev_offset.attr,
2174 	&rdev_size.attr,
2175 	NULL,
2176 };
2177 static ssize_t
2178 rdev_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
2179 {
2180 	struct rdev_sysfs_entry *entry = container_of(attr, struct rdev_sysfs_entry, attr);
2181 	mdk_rdev_t *rdev = container_of(kobj, mdk_rdev_t, kobj);
2182 	mddev_t *mddev = rdev->mddev;
2183 	ssize_t rv;
2184 
2185 	if (!entry->show)
2186 		return -EIO;
2187 
2188 	rv = mddev ? mddev_lock(mddev) : -EBUSY;
2189 	if (!rv) {
2190 		if (rdev->mddev == NULL)
2191 			rv = -EBUSY;
2192 		else
2193 			rv = entry->show(rdev, page);
2194 		mddev_unlock(mddev);
2195 	}
2196 	return rv;
2197 }
2198 
2199 static ssize_t
2200 rdev_attr_store(struct kobject *kobj, struct attribute *attr,
2201 	      const char *page, size_t length)
2202 {
2203 	struct rdev_sysfs_entry *entry = container_of(attr, struct rdev_sysfs_entry, attr);
2204 	mdk_rdev_t *rdev = container_of(kobj, mdk_rdev_t, kobj);
2205 	ssize_t rv;
2206 	mddev_t *mddev = rdev->mddev;
2207 
2208 	if (!entry->store)
2209 		return -EIO;
2210 	if (!capable(CAP_SYS_ADMIN))
2211 		return -EACCES;
2212 	rv = mddev ? mddev_lock(mddev): -EBUSY;
2213 	if (!rv) {
2214 		if (rdev->mddev == NULL)
2215 			rv = -EBUSY;
2216 		else
2217 			rv = entry->store(rdev, page, length);
2218 		mddev_unlock(mddev);
2219 	}
2220 	return rv;
2221 }
2222 
2223 static void rdev_free(struct kobject *ko)
2224 {
2225 	mdk_rdev_t *rdev = container_of(ko, mdk_rdev_t, kobj);
2226 	kfree(rdev);
2227 }
2228 static struct sysfs_ops rdev_sysfs_ops = {
2229 	.show		= rdev_attr_show,
2230 	.store		= rdev_attr_store,
2231 };
2232 static struct kobj_type rdev_ktype = {
2233 	.release	= rdev_free,
2234 	.sysfs_ops	= &rdev_sysfs_ops,
2235 	.default_attrs	= rdev_default_attrs,
2236 };
2237 
2238 /*
2239  * Import a device. If 'super_format' >= 0, then sanity check the superblock
2240  *
2241  * mark the device faulty if:
2242  *
2243  *   - the device is nonexistent (zero size)
2244  *   - the device has no valid superblock
2245  *
2246  * a faulty rdev _never_ has rdev->sb set.
2247  */
2248 static mdk_rdev_t *md_import_device(dev_t newdev, int super_format, int super_minor)
2249 {
2250 	char b[BDEVNAME_SIZE];
2251 	int err;
2252 	mdk_rdev_t *rdev;
2253 	sector_t size;
2254 
2255 	rdev = kzalloc(sizeof(*rdev), GFP_KERNEL);
2256 	if (!rdev) {
2257 		printk(KERN_ERR "md: could not alloc mem for new device!\n");
2258 		return ERR_PTR(-ENOMEM);
2259 	}
2260 
2261 	if ((err = alloc_disk_sb(rdev)))
2262 		goto abort_free;
2263 
2264 	err = lock_rdev(rdev, newdev, super_format == -2);
2265 	if (err)
2266 		goto abort_free;
2267 
2268 	kobject_init(&rdev->kobj, &rdev_ktype);
2269 
2270 	rdev->desc_nr = -1;
2271 	rdev->saved_raid_disk = -1;
2272 	rdev->raid_disk = -1;
2273 	rdev->flags = 0;
2274 	rdev->data_offset = 0;
2275 	rdev->sb_events = 0;
2276 	atomic_set(&rdev->nr_pending, 0);
2277 	atomic_set(&rdev->read_errors, 0);
2278 	atomic_set(&rdev->corrected_errors, 0);
2279 
2280 	size = rdev->bdev->bd_inode->i_size >> BLOCK_SIZE_BITS;
2281 	if (!size) {
2282 		printk(KERN_WARNING
2283 			"md: %s has zero or unknown size, marking faulty!\n",
2284 			bdevname(rdev->bdev,b));
2285 		err = -EINVAL;
2286 		goto abort_free;
2287 	}
2288 
2289 	if (super_format >= 0) {
2290 		err = super_types[super_format].
2291 			load_super(rdev, NULL, super_minor);
2292 		if (err == -EINVAL) {
2293 			printk(KERN_WARNING
2294 				"md: %s does not have a valid v%d.%d "
2295 			       "superblock, not importing!\n",
2296 				bdevname(rdev->bdev,b),
2297 			       super_format, super_minor);
2298 			goto abort_free;
2299 		}
2300 		if (err < 0) {
2301 			printk(KERN_WARNING
2302 				"md: could not read %s's sb, not importing!\n",
2303 				bdevname(rdev->bdev,b));
2304 			goto abort_free;
2305 		}
2306 	}
2307 
2308 	INIT_LIST_HEAD(&rdev->same_set);
2309 	init_waitqueue_head(&rdev->blocked_wait);
2310 
2311 	return rdev;
2312 
2313 abort_free:
2314 	if (rdev->sb_page) {
2315 		if (rdev->bdev)
2316 			unlock_rdev(rdev);
2317 		free_disk_sb(rdev);
2318 	}
2319 	kfree(rdev);
2320 	return ERR_PTR(err);
2321 }
2322 
2323 /*
2324  * Check a full RAID array for plausibility
2325  */
2326 
2327 
2328 static void analyze_sbs(mddev_t * mddev)
2329 {
2330 	int i;
2331 	struct list_head *tmp;
2332 	mdk_rdev_t *rdev, *freshest;
2333 	char b[BDEVNAME_SIZE];
2334 
2335 	freshest = NULL;
2336 	rdev_for_each(rdev, tmp, mddev)
2337 		switch (super_types[mddev->major_version].
2338 			load_super(rdev, freshest, mddev->minor_version)) {
2339 		case 1:
2340 			freshest = rdev;
2341 			break;
2342 		case 0:
2343 			break;
2344 		default:
2345 			printk( KERN_ERR \
2346 				"md: fatal superblock inconsistency in %s"
2347 				" -- removing from array\n",
2348 				bdevname(rdev->bdev,b));
2349 			kick_rdev_from_array(rdev);
2350 		}
2351 
2352 
2353 	super_types[mddev->major_version].
2354 		validate_super(mddev, freshest);
2355 
2356 	i = 0;
2357 	rdev_for_each(rdev, tmp, mddev) {
2358 		if (rdev != freshest)
2359 			if (super_types[mddev->major_version].
2360 			    validate_super(mddev, rdev)) {
2361 				printk(KERN_WARNING "md: kicking non-fresh %s"
2362 					" from array!\n",
2363 					bdevname(rdev->bdev,b));
2364 				kick_rdev_from_array(rdev);
2365 				continue;
2366 			}
2367 		if (mddev->level == LEVEL_MULTIPATH) {
2368 			rdev->desc_nr = i++;
2369 			rdev->raid_disk = rdev->desc_nr;
2370 			set_bit(In_sync, &rdev->flags);
2371 		} else if (rdev->raid_disk >= mddev->raid_disks) {
2372 			rdev->raid_disk = -1;
2373 			clear_bit(In_sync, &rdev->flags);
2374 		}
2375 	}
2376 
2377 
2378 
2379 	if (mddev->recovery_cp != MaxSector &&
2380 	    mddev->level >= 1)
2381 		printk(KERN_ERR "md: %s: raid array is not clean"
2382 		       " -- starting background reconstruction\n",
2383 		       mdname(mddev));
2384 
2385 }
2386 
2387 static void md_safemode_timeout(unsigned long data);
2388 
2389 static ssize_t
2390 safe_delay_show(mddev_t *mddev, char *page)
2391 {
2392 	int msec = (mddev->safemode_delay*1000)/HZ;
2393 	return sprintf(page, "%d.%03d\n", msec/1000, msec%1000);
2394 }
2395 static ssize_t
2396 safe_delay_store(mddev_t *mddev, const char *cbuf, size_t len)
2397 {
2398 	int scale=1;
2399 	int dot=0;
2400 	int i;
2401 	unsigned long msec;
2402 	char buf[30];
2403 
2404 	/* remove a period, and count digits after it */
2405 	if (len >= sizeof(buf))
2406 		return -EINVAL;
2407 	strlcpy(buf, cbuf, sizeof(buf));
2408 	for (i=0; i<len; i++) {
2409 		if (dot) {
2410 			if (isdigit(buf[i])) {
2411 				buf[i-1] = buf[i];
2412 				scale *= 10;
2413 			}
2414 			buf[i] = 0;
2415 		} else if (buf[i] == '.') {
2416 			dot=1;
2417 			buf[i] = 0;
2418 		}
2419 	}
2420 	if (strict_strtoul(buf, 10, &msec) < 0)
2421 		return -EINVAL;
2422 	msec = (msec * 1000) / scale;
2423 	if (msec == 0)
2424 		mddev->safemode_delay = 0;
2425 	else {
2426 		unsigned long old_delay = mddev->safemode_delay;
2427 		mddev->safemode_delay = (msec*HZ)/1000;
2428 		if (mddev->safemode_delay == 0)
2429 			mddev->safemode_delay = 1;
2430 		if (mddev->safemode_delay < old_delay)
2431 			md_safemode_timeout((unsigned long)mddev);
2432 	}
2433 	return len;
2434 }
2435 static struct md_sysfs_entry md_safe_delay =
2436 __ATTR(safe_mode_delay, S_IRUGO|S_IWUSR,safe_delay_show, safe_delay_store);
2437 
2438 static ssize_t
2439 level_show(mddev_t *mddev, char *page)
2440 {
2441 	struct mdk_personality *p = mddev->pers;
2442 	if (p)
2443 		return sprintf(page, "%s\n", p->name);
2444 	else if (mddev->clevel[0])
2445 		return sprintf(page, "%s\n", mddev->clevel);
2446 	else if (mddev->level != LEVEL_NONE)
2447 		return sprintf(page, "%d\n", mddev->level);
2448 	else
2449 		return 0;
2450 }
2451 
2452 static ssize_t
2453 level_store(mddev_t *mddev, const char *buf, size_t len)
2454 {
2455 	ssize_t rv = len;
2456 	if (mddev->pers)
2457 		return -EBUSY;
2458 	if (len == 0)
2459 		return 0;
2460 	if (len >= sizeof(mddev->clevel))
2461 		return -ENOSPC;
2462 	strncpy(mddev->clevel, buf, len);
2463 	if (mddev->clevel[len-1] == '\n')
2464 		len--;
2465 	mddev->clevel[len] = 0;
2466 	mddev->level = LEVEL_NONE;
2467 	return rv;
2468 }
2469 
2470 static struct md_sysfs_entry md_level =
2471 __ATTR(level, S_IRUGO|S_IWUSR, level_show, level_store);
2472 
2473 
2474 static ssize_t
2475 layout_show(mddev_t *mddev, char *page)
2476 {
2477 	/* just a number, not meaningful for all levels */
2478 	if (mddev->reshape_position != MaxSector &&
2479 	    mddev->layout != mddev->new_layout)
2480 		return sprintf(page, "%d (%d)\n",
2481 			       mddev->new_layout, mddev->layout);
2482 	return sprintf(page, "%d\n", mddev->layout);
2483 }
2484 
2485 static ssize_t
2486 layout_store(mddev_t *mddev, const char *buf, size_t len)
2487 {
2488 	char *e;
2489 	unsigned long n = simple_strtoul(buf, &e, 10);
2490 
2491 	if (!*buf || (*e && *e != '\n'))
2492 		return -EINVAL;
2493 
2494 	if (mddev->pers)
2495 		return -EBUSY;
2496 	if (mddev->reshape_position != MaxSector)
2497 		mddev->new_layout = n;
2498 	else
2499 		mddev->layout = n;
2500 	return len;
2501 }
2502 static struct md_sysfs_entry md_layout =
2503 __ATTR(layout, S_IRUGO|S_IWUSR, layout_show, layout_store);
2504 
2505 
2506 static ssize_t
2507 raid_disks_show(mddev_t *mddev, char *page)
2508 {
2509 	if (mddev->raid_disks == 0)
2510 		return 0;
2511 	if (mddev->reshape_position != MaxSector &&
2512 	    mddev->delta_disks != 0)
2513 		return sprintf(page, "%d (%d)\n", mddev->raid_disks,
2514 			       mddev->raid_disks - mddev->delta_disks);
2515 	return sprintf(page, "%d\n", mddev->raid_disks);
2516 }
2517 
2518 static int update_raid_disks(mddev_t *mddev, int raid_disks);
2519 
2520 static ssize_t
2521 raid_disks_store(mddev_t *mddev, const char *buf, size_t len)
2522 {
2523 	char *e;
2524 	int rv = 0;
2525 	unsigned long n = simple_strtoul(buf, &e, 10);
2526 
2527 	if (!*buf || (*e && *e != '\n'))
2528 		return -EINVAL;
2529 
2530 	if (mddev->pers)
2531 		rv = update_raid_disks(mddev, n);
2532 	else if (mddev->reshape_position != MaxSector) {
2533 		int olddisks = mddev->raid_disks - mddev->delta_disks;
2534 		mddev->delta_disks = n - olddisks;
2535 		mddev->raid_disks = n;
2536 	} else
2537 		mddev->raid_disks = n;
2538 	return rv ? rv : len;
2539 }
2540 static struct md_sysfs_entry md_raid_disks =
2541 __ATTR(raid_disks, S_IRUGO|S_IWUSR, raid_disks_show, raid_disks_store);
2542 
2543 static ssize_t
2544 chunk_size_show(mddev_t *mddev, char *page)
2545 {
2546 	if (mddev->reshape_position != MaxSector &&
2547 	    mddev->chunk_size != mddev->new_chunk)
2548 		return sprintf(page, "%d (%d)\n", mddev->new_chunk,
2549 			       mddev->chunk_size);
2550 	return sprintf(page, "%d\n", mddev->chunk_size);
2551 }
2552 
2553 static ssize_t
2554 chunk_size_store(mddev_t *mddev, const char *buf, size_t len)
2555 {
2556 	/* can only set chunk_size if array is not yet active */
2557 	char *e;
2558 	unsigned long n = simple_strtoul(buf, &e, 10);
2559 
2560 	if (!*buf || (*e && *e != '\n'))
2561 		return -EINVAL;
2562 
2563 	if (mddev->pers)
2564 		return -EBUSY;
2565 	else if (mddev->reshape_position != MaxSector)
2566 		mddev->new_chunk = n;
2567 	else
2568 		mddev->chunk_size = n;
2569 	return len;
2570 }
2571 static struct md_sysfs_entry md_chunk_size =
2572 __ATTR(chunk_size, S_IRUGO|S_IWUSR, chunk_size_show, chunk_size_store);
2573 
2574 static ssize_t
2575 resync_start_show(mddev_t *mddev, char *page)
2576 {
2577 	return sprintf(page, "%llu\n", (unsigned long long)mddev->recovery_cp);
2578 }
2579 
2580 static ssize_t
2581 resync_start_store(mddev_t *mddev, const char *buf, size_t len)
2582 {
2583 	char *e;
2584 	unsigned long long n = simple_strtoull(buf, &e, 10);
2585 
2586 	if (mddev->pers)
2587 		return -EBUSY;
2588 	if (!*buf || (*e && *e != '\n'))
2589 		return -EINVAL;
2590 
2591 	mddev->recovery_cp = n;
2592 	return len;
2593 }
2594 static struct md_sysfs_entry md_resync_start =
2595 __ATTR(resync_start, S_IRUGO|S_IWUSR, resync_start_show, resync_start_store);
2596 
2597 /*
2598  * The array state can be:
2599  *
2600  * clear
2601  *     No devices, no size, no level
2602  *     Equivalent to STOP_ARRAY ioctl
2603  * inactive
2604  *     May have some settings, but array is not active
2605  *        all IO results in error
2606  *     When written, doesn't tear down array, but just stops it
2607  * suspended (not supported yet)
2608  *     All IO requests will block. The array can be reconfigured.
2609  *     Writing this, if accepted, will block until array is quiescent
2610  * readonly
2611  *     no resync can happen.  no superblocks get written.
2612  *     write requests fail
2613  * read-auto
2614  *     like readonly, but behaves like 'clean' on a write request.
2615  *
2616  * clean - no pending writes, but otherwise active.
2617  *     When written to inactive array, starts without resync
2618  *     If a write request arrives then
2619  *       if metadata is known, mark 'dirty' and switch to 'active'.
2620  *       if not known, block and switch to write-pending
2621  *     If written to an active array that has pending writes, then fails.
2622  * active
2623  *     fully active: IO and resync can be happening.
2624  *     When written to inactive array, starts with resync
2625  *
2626  * write-pending
2627  *     clean, but writes are blocked waiting for 'active' to be written.
2628  *
2629  * active-idle
2630  *     like active, but no writes have been seen for a while (100msec).
2631  *
2632  */
2633 enum array_state { clear, inactive, suspended, readonly, read_auto, clean, active,
2634 		   write_pending, active_idle, bad_word};
2635 static char *array_states[] = {
2636 	"clear", "inactive", "suspended", "readonly", "read-auto", "clean", "active",
2637 	"write-pending", "active-idle", NULL };
2638 
2639 static int match_word(const char *word, char **list)
2640 {
2641 	int n;
2642 	for (n=0; list[n]; n++)
2643 		if (cmd_match(word, list[n]))
2644 			break;
2645 	return n;
2646 }
2647 
2648 static ssize_t
2649 array_state_show(mddev_t *mddev, char *page)
2650 {
2651 	enum array_state st = inactive;
2652 
2653 	if (mddev->pers)
2654 		switch(mddev->ro) {
2655 		case 1:
2656 			st = readonly;
2657 			break;
2658 		case 2:
2659 			st = read_auto;
2660 			break;
2661 		case 0:
2662 			if (mddev->in_sync)
2663 				st = clean;
2664 			else if (test_bit(MD_CHANGE_CLEAN, &mddev->flags))
2665 				st = write_pending;
2666 			else if (mddev->safemode)
2667 				st = active_idle;
2668 			else
2669 				st = active;
2670 		}
2671 	else {
2672 		if (list_empty(&mddev->disks) &&
2673 		    mddev->raid_disks == 0 &&
2674 		    mddev->size == 0)
2675 			st = clear;
2676 		else
2677 			st = inactive;
2678 	}
2679 	return sprintf(page, "%s\n", array_states[st]);
2680 }
2681 
2682 static int do_md_stop(mddev_t * mddev, int ro, int is_open);
2683 static int do_md_run(mddev_t * mddev);
2684 static int restart_array(mddev_t *mddev);
2685 
2686 static ssize_t
2687 array_state_store(mddev_t *mddev, const char *buf, size_t len)
2688 {
2689 	int err = -EINVAL;
2690 	enum array_state st = match_word(buf, array_states);
2691 	switch(st) {
2692 	case bad_word:
2693 		break;
2694 	case clear:
2695 		/* stopping an active array */
2696 		if (atomic_read(&mddev->openers) > 0)
2697 			return -EBUSY;
2698 		err = do_md_stop(mddev, 0, 0);
2699 		break;
2700 	case inactive:
2701 		/* stopping an active array */
2702 		if (mddev->pers) {
2703 			if (atomic_read(&mddev->openers) > 0)
2704 				return -EBUSY;
2705 			err = do_md_stop(mddev, 2, 0);
2706 		} else
2707 			err = 0; /* already inactive */
2708 		break;
2709 	case suspended:
2710 		break; /* not supported yet */
2711 	case readonly:
2712 		if (mddev->pers)
2713 			err = do_md_stop(mddev, 1, 0);
2714 		else {
2715 			mddev->ro = 1;
2716 			set_disk_ro(mddev->gendisk, 1);
2717 			err = do_md_run(mddev);
2718 		}
2719 		break;
2720 	case read_auto:
2721 		if (mddev->pers) {
2722 			if (mddev->ro == 0)
2723 				err = do_md_stop(mddev, 1, 0);
2724 			else if (mddev->ro == 1)
2725 				err = restart_array(mddev);
2726 			if (err == 0) {
2727 				mddev->ro = 2;
2728 				set_disk_ro(mddev->gendisk, 0);
2729 			}
2730 		} else {
2731 			mddev->ro = 2;
2732 			err = do_md_run(mddev);
2733 		}
2734 		break;
2735 	case clean:
2736 		if (mddev->pers) {
2737 			restart_array(mddev);
2738 			spin_lock_irq(&mddev->write_lock);
2739 			if (atomic_read(&mddev->writes_pending) == 0) {
2740 				if (mddev->in_sync == 0) {
2741 					mddev->in_sync = 1;
2742 					if (mddev->safemode == 1)
2743 						mddev->safemode = 0;
2744 					if (mddev->persistent)
2745 						set_bit(MD_CHANGE_CLEAN,
2746 							&mddev->flags);
2747 				}
2748 				err = 0;
2749 			} else
2750 				err = -EBUSY;
2751 			spin_unlock_irq(&mddev->write_lock);
2752 		} else {
2753 			mddev->ro = 0;
2754 			mddev->recovery_cp = MaxSector;
2755 			err = do_md_run(mddev);
2756 		}
2757 		break;
2758 	case active:
2759 		if (mddev->pers) {
2760 			restart_array(mddev);
2761 			if (mddev->external)
2762 				clear_bit(MD_CHANGE_CLEAN, &mddev->flags);
2763 			wake_up(&mddev->sb_wait);
2764 			err = 0;
2765 		} else {
2766 			mddev->ro = 0;
2767 			set_disk_ro(mddev->gendisk, 0);
2768 			err = do_md_run(mddev);
2769 		}
2770 		break;
2771 	case write_pending:
2772 	case active_idle:
2773 		/* these cannot be set */
2774 		break;
2775 	}
2776 	if (err)
2777 		return err;
2778 	else {
2779 		sysfs_notify_dirent(mddev->sysfs_state);
2780 		return len;
2781 	}
2782 }
2783 static struct md_sysfs_entry md_array_state =
2784 __ATTR(array_state, S_IRUGO|S_IWUSR, array_state_show, array_state_store);
2785 
2786 static ssize_t
2787 null_show(mddev_t *mddev, char *page)
2788 {
2789 	return -EINVAL;
2790 }
2791 
2792 static ssize_t
2793 new_dev_store(mddev_t *mddev, const char *buf, size_t len)
2794 {
2795 	/* buf must be %d:%d\n? giving major and minor numbers */
2796 	/* The new device is added to the array.
2797 	 * If the array has a persistent superblock, we read the
2798 	 * superblock to initialise info and check validity.
2799 	 * Otherwise, only checking done is that in bind_rdev_to_array,
2800 	 * which mainly checks size.
2801 	 */
2802 	char *e;
2803 	int major = simple_strtoul(buf, &e, 10);
2804 	int minor;
2805 	dev_t dev;
2806 	mdk_rdev_t *rdev;
2807 	int err;
2808 
2809 	if (!*buf || *e != ':' || !e[1] || e[1] == '\n')
2810 		return -EINVAL;
2811 	minor = simple_strtoul(e+1, &e, 10);
2812 	if (*e && *e != '\n')
2813 		return -EINVAL;
2814 	dev = MKDEV(major, minor);
2815 	if (major != MAJOR(dev) ||
2816 	    minor != MINOR(dev))
2817 		return -EOVERFLOW;
2818 
2819 
2820 	if (mddev->persistent) {
2821 		rdev = md_import_device(dev, mddev->major_version,
2822 					mddev->minor_version);
2823 		if (!IS_ERR(rdev) && !list_empty(&mddev->disks)) {
2824 			mdk_rdev_t *rdev0 = list_entry(mddev->disks.next,
2825 						       mdk_rdev_t, same_set);
2826 			err = super_types[mddev->major_version]
2827 				.load_super(rdev, rdev0, mddev->minor_version);
2828 			if (err < 0)
2829 				goto out;
2830 		}
2831 	} else if (mddev->external)
2832 		rdev = md_import_device(dev, -2, -1);
2833 	else
2834 		rdev = md_import_device(dev, -1, -1);
2835 
2836 	if (IS_ERR(rdev))
2837 		return PTR_ERR(rdev);
2838 	err = bind_rdev_to_array(rdev, mddev);
2839  out:
2840 	if (err)
2841 		export_rdev(rdev);
2842 	return err ? err : len;
2843 }
2844 
2845 static struct md_sysfs_entry md_new_device =
2846 __ATTR(new_dev, S_IWUSR, null_show, new_dev_store);
2847 
2848 static ssize_t
2849 bitmap_store(mddev_t *mddev, const char *buf, size_t len)
2850 {
2851 	char *end;
2852 	unsigned long chunk, end_chunk;
2853 
2854 	if (!mddev->bitmap)
2855 		goto out;
2856 	/* buf should be <chunk> <chunk> ... or <chunk>-<chunk> ... (range) */
2857 	while (*buf) {
2858 		chunk = end_chunk = simple_strtoul(buf, &end, 0);
2859 		if (buf == end) break;
2860 		if (*end == '-') { /* range */
2861 			buf = end + 1;
2862 			end_chunk = simple_strtoul(buf, &end, 0);
2863 			if (buf == end) break;
2864 		}
2865 		if (*end && !isspace(*end)) break;
2866 		bitmap_dirty_bits(mddev->bitmap, chunk, end_chunk);
2867 		buf = end;
2868 		while (isspace(*buf)) buf++;
2869 	}
2870 	bitmap_unplug(mddev->bitmap); /* flush the bits to disk */
2871 out:
2872 	return len;
2873 }
2874 
2875 static struct md_sysfs_entry md_bitmap =
2876 __ATTR(bitmap_set_bits, S_IWUSR, null_show, bitmap_store);
2877 
2878 static ssize_t
2879 size_show(mddev_t *mddev, char *page)
2880 {
2881 	return sprintf(page, "%llu\n", (unsigned long long)mddev->size);
2882 }
2883 
2884 static int update_size(mddev_t *mddev, sector_t num_sectors);
2885 
2886 static ssize_t
2887 size_store(mddev_t *mddev, const char *buf, size_t len)
2888 {
2889 	/* If array is inactive, we can reduce the component size, but
2890 	 * not increase it (except from 0).
2891 	 * If array is active, we can try an on-line resize
2892 	 */
2893 	char *e;
2894 	int err = 0;
2895 	unsigned long long size = simple_strtoull(buf, &e, 10);
2896 	if (!*buf || *buf == '\n' ||
2897 	    (*e && *e != '\n'))
2898 		return -EINVAL;
2899 
2900 	if (mddev->pers) {
2901 		err = update_size(mddev, size * 2);
2902 		md_update_sb(mddev, 1);
2903 	} else {
2904 		if (mddev->size == 0 ||
2905 		    mddev->size > size)
2906 			mddev->size = size;
2907 		else
2908 			err = -ENOSPC;
2909 	}
2910 	return err ? err : len;
2911 }
2912 
2913 static struct md_sysfs_entry md_size =
2914 __ATTR(component_size, S_IRUGO|S_IWUSR, size_show, size_store);
2915 
2916 
2917 /* Metdata version.
2918  * This is one of
2919  *   'none' for arrays with no metadata (good luck...)
2920  *   'external' for arrays with externally managed metadata,
2921  * or N.M for internally known formats
2922  */
2923 static ssize_t
2924 metadata_show(mddev_t *mddev, char *page)
2925 {
2926 	if (mddev->persistent)
2927 		return sprintf(page, "%d.%d\n",
2928 			       mddev->major_version, mddev->minor_version);
2929 	else if (mddev->external)
2930 		return sprintf(page, "external:%s\n", mddev->metadata_type);
2931 	else
2932 		return sprintf(page, "none\n");
2933 }
2934 
2935 static ssize_t
2936 metadata_store(mddev_t *mddev, const char *buf, size_t len)
2937 {
2938 	int major, minor;
2939 	char *e;
2940 	/* Changing the details of 'external' metadata is
2941 	 * always permitted.  Otherwise there must be
2942 	 * no devices attached to the array.
2943 	 */
2944 	if (mddev->external && strncmp(buf, "external:", 9) == 0)
2945 		;
2946 	else if (!list_empty(&mddev->disks))
2947 		return -EBUSY;
2948 
2949 	if (cmd_match(buf, "none")) {
2950 		mddev->persistent = 0;
2951 		mddev->external = 0;
2952 		mddev->major_version = 0;
2953 		mddev->minor_version = 90;
2954 		return len;
2955 	}
2956 	if (strncmp(buf, "external:", 9) == 0) {
2957 		size_t namelen = len-9;
2958 		if (namelen >= sizeof(mddev->metadata_type))
2959 			namelen = sizeof(mddev->metadata_type)-1;
2960 		strncpy(mddev->metadata_type, buf+9, namelen);
2961 		mddev->metadata_type[namelen] = 0;
2962 		if (namelen && mddev->metadata_type[namelen-1] == '\n')
2963 			mddev->metadata_type[--namelen] = 0;
2964 		mddev->persistent = 0;
2965 		mddev->external = 1;
2966 		mddev->major_version = 0;
2967 		mddev->minor_version = 90;
2968 		return len;
2969 	}
2970 	major = simple_strtoul(buf, &e, 10);
2971 	if (e==buf || *e != '.')
2972 		return -EINVAL;
2973 	buf = e+1;
2974 	minor = simple_strtoul(buf, &e, 10);
2975 	if (e==buf || (*e && *e != '\n') )
2976 		return -EINVAL;
2977 	if (major >= ARRAY_SIZE(super_types) || super_types[major].name == NULL)
2978 		return -ENOENT;
2979 	mddev->major_version = major;
2980 	mddev->minor_version = minor;
2981 	mddev->persistent = 1;
2982 	mddev->external = 0;
2983 	return len;
2984 }
2985 
2986 static struct md_sysfs_entry md_metadata =
2987 __ATTR(metadata_version, S_IRUGO|S_IWUSR, metadata_show, metadata_store);
2988 
2989 static ssize_t
2990 action_show(mddev_t *mddev, char *page)
2991 {
2992 	char *type = "idle";
2993 	if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
2994 	    (!mddev->ro && test_bit(MD_RECOVERY_NEEDED, &mddev->recovery))) {
2995 		if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
2996 			type = "reshape";
2997 		else if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
2998 			if (!test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
2999 				type = "resync";
3000 			else if (test_bit(MD_RECOVERY_CHECK, &mddev->recovery))
3001 				type = "check";
3002 			else
3003 				type = "repair";
3004 		} else if (test_bit(MD_RECOVERY_RECOVER, &mddev->recovery))
3005 			type = "recover";
3006 	}
3007 	return sprintf(page, "%s\n", type);
3008 }
3009 
3010 static ssize_t
3011 action_store(mddev_t *mddev, const char *page, size_t len)
3012 {
3013 	if (!mddev->pers || !mddev->pers->sync_request)
3014 		return -EINVAL;
3015 
3016 	if (cmd_match(page, "idle")) {
3017 		if (mddev->sync_thread) {
3018 			set_bit(MD_RECOVERY_INTR, &mddev->recovery);
3019 			md_unregister_thread(mddev->sync_thread);
3020 			mddev->sync_thread = NULL;
3021 			mddev->recovery = 0;
3022 		}
3023 	} else if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
3024 		   test_bit(MD_RECOVERY_NEEDED, &mddev->recovery))
3025 		return -EBUSY;
3026 	else if (cmd_match(page, "resync"))
3027 		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
3028 	else if (cmd_match(page, "recover")) {
3029 		set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
3030 		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
3031 	} else if (cmd_match(page, "reshape")) {
3032 		int err;
3033 		if (mddev->pers->start_reshape == NULL)
3034 			return -EINVAL;
3035 		err = mddev->pers->start_reshape(mddev);
3036 		if (err)
3037 			return err;
3038 		sysfs_notify(&mddev->kobj, NULL, "degraded");
3039 	} else {
3040 		if (cmd_match(page, "check"))
3041 			set_bit(MD_RECOVERY_CHECK, &mddev->recovery);
3042 		else if (!cmd_match(page, "repair"))
3043 			return -EINVAL;
3044 		set_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
3045 		set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
3046 	}
3047 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
3048 	md_wakeup_thread(mddev->thread);
3049 	sysfs_notify(&mddev->kobj, NULL, "sync_action");
3050 	return len;
3051 }
3052 
3053 static ssize_t
3054 mismatch_cnt_show(mddev_t *mddev, char *page)
3055 {
3056 	return sprintf(page, "%llu\n",
3057 		       (unsigned long long) mddev->resync_mismatches);
3058 }
3059 
3060 static struct md_sysfs_entry md_scan_mode =
3061 __ATTR(sync_action, S_IRUGO|S_IWUSR, action_show, action_store);
3062 
3063 
3064 static struct md_sysfs_entry md_mismatches = __ATTR_RO(mismatch_cnt);
3065 
3066 static ssize_t
3067 sync_min_show(mddev_t *mddev, char *page)
3068 {
3069 	return sprintf(page, "%d (%s)\n", speed_min(mddev),
3070 		       mddev->sync_speed_min ? "local": "system");
3071 }
3072 
3073 static ssize_t
3074 sync_min_store(mddev_t *mddev, const char *buf, size_t len)
3075 {
3076 	int min;
3077 	char *e;
3078 	if (strncmp(buf, "system", 6)==0) {
3079 		mddev->sync_speed_min = 0;
3080 		return len;
3081 	}
3082 	min = simple_strtoul(buf, &e, 10);
3083 	if (buf == e || (*e && *e != '\n') || min <= 0)
3084 		return -EINVAL;
3085 	mddev->sync_speed_min = min;
3086 	return len;
3087 }
3088 
3089 static struct md_sysfs_entry md_sync_min =
3090 __ATTR(sync_speed_min, S_IRUGO|S_IWUSR, sync_min_show, sync_min_store);
3091 
3092 static ssize_t
3093 sync_max_show(mddev_t *mddev, char *page)
3094 {
3095 	return sprintf(page, "%d (%s)\n", speed_max(mddev),
3096 		       mddev->sync_speed_max ? "local": "system");
3097 }
3098 
3099 static ssize_t
3100 sync_max_store(mddev_t *mddev, const char *buf, size_t len)
3101 {
3102 	int max;
3103 	char *e;
3104 	if (strncmp(buf, "system", 6)==0) {
3105 		mddev->sync_speed_max = 0;
3106 		return len;
3107 	}
3108 	max = simple_strtoul(buf, &e, 10);
3109 	if (buf == e || (*e && *e != '\n') || max <= 0)
3110 		return -EINVAL;
3111 	mddev->sync_speed_max = max;
3112 	return len;
3113 }
3114 
3115 static struct md_sysfs_entry md_sync_max =
3116 __ATTR(sync_speed_max, S_IRUGO|S_IWUSR, sync_max_show, sync_max_store);
3117 
3118 static ssize_t
3119 degraded_show(mddev_t *mddev, char *page)
3120 {
3121 	return sprintf(page, "%d\n", mddev->degraded);
3122 }
3123 static struct md_sysfs_entry md_degraded = __ATTR_RO(degraded);
3124 
3125 static ssize_t
3126 sync_force_parallel_show(mddev_t *mddev, char *page)
3127 {
3128 	return sprintf(page, "%d\n", mddev->parallel_resync);
3129 }
3130 
3131 static ssize_t
3132 sync_force_parallel_store(mddev_t *mddev, const char *buf, size_t len)
3133 {
3134 	long n;
3135 
3136 	if (strict_strtol(buf, 10, &n))
3137 		return -EINVAL;
3138 
3139 	if (n != 0 && n != 1)
3140 		return -EINVAL;
3141 
3142 	mddev->parallel_resync = n;
3143 
3144 	if (mddev->sync_thread)
3145 		wake_up(&resync_wait);
3146 
3147 	return len;
3148 }
3149 
3150 /* force parallel resync, even with shared block devices */
3151 static struct md_sysfs_entry md_sync_force_parallel =
3152 __ATTR(sync_force_parallel, S_IRUGO|S_IWUSR,
3153        sync_force_parallel_show, sync_force_parallel_store);
3154 
3155 static ssize_t
3156 sync_speed_show(mddev_t *mddev, char *page)
3157 {
3158 	unsigned long resync, dt, db;
3159 	resync = mddev->curr_mark_cnt - atomic_read(&mddev->recovery_active);
3160 	dt = (jiffies - mddev->resync_mark) / HZ;
3161 	if (!dt) dt++;
3162 	db = resync - mddev->resync_mark_cnt;
3163 	return sprintf(page, "%lu\n", db/dt/2); /* K/sec */
3164 }
3165 
3166 static struct md_sysfs_entry md_sync_speed = __ATTR_RO(sync_speed);
3167 
3168 static ssize_t
3169 sync_completed_show(mddev_t *mddev, char *page)
3170 {
3171 	unsigned long max_blocks, resync;
3172 
3173 	if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery))
3174 		max_blocks = mddev->resync_max_sectors;
3175 	else
3176 		max_blocks = mddev->size << 1;
3177 
3178 	resync = (mddev->curr_resync - atomic_read(&mddev->recovery_active));
3179 	return sprintf(page, "%lu / %lu\n", resync, max_blocks);
3180 }
3181 
3182 static struct md_sysfs_entry md_sync_completed = __ATTR_RO(sync_completed);
3183 
3184 static ssize_t
3185 min_sync_show(mddev_t *mddev, char *page)
3186 {
3187 	return sprintf(page, "%llu\n",
3188 		       (unsigned long long)mddev->resync_min);
3189 }
3190 static ssize_t
3191 min_sync_store(mddev_t *mddev, const char *buf, size_t len)
3192 {
3193 	unsigned long long min;
3194 	if (strict_strtoull(buf, 10, &min))
3195 		return -EINVAL;
3196 	if (min > mddev->resync_max)
3197 		return -EINVAL;
3198 	if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
3199 		return -EBUSY;
3200 
3201 	/* Must be a multiple of chunk_size */
3202 	if (mddev->chunk_size) {
3203 		if (min & (sector_t)((mddev->chunk_size>>9)-1))
3204 			return -EINVAL;
3205 	}
3206 	mddev->resync_min = min;
3207 
3208 	return len;
3209 }
3210 
3211 static struct md_sysfs_entry md_min_sync =
3212 __ATTR(sync_min, S_IRUGO|S_IWUSR, min_sync_show, min_sync_store);
3213 
3214 static ssize_t
3215 max_sync_show(mddev_t *mddev, char *page)
3216 {
3217 	if (mddev->resync_max == MaxSector)
3218 		return sprintf(page, "max\n");
3219 	else
3220 		return sprintf(page, "%llu\n",
3221 			       (unsigned long long)mddev->resync_max);
3222 }
3223 static ssize_t
3224 max_sync_store(mddev_t *mddev, const char *buf, size_t len)
3225 {
3226 	if (strncmp(buf, "max", 3) == 0)
3227 		mddev->resync_max = MaxSector;
3228 	else {
3229 		unsigned long long max;
3230 		if (strict_strtoull(buf, 10, &max))
3231 			return -EINVAL;
3232 		if (max < mddev->resync_min)
3233 			return -EINVAL;
3234 		if (max < mddev->resync_max &&
3235 		    test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
3236 			return -EBUSY;
3237 
3238 		/* Must be a multiple of chunk_size */
3239 		if (mddev->chunk_size) {
3240 			if (max & (sector_t)((mddev->chunk_size>>9)-1))
3241 				return -EINVAL;
3242 		}
3243 		mddev->resync_max = max;
3244 	}
3245 	wake_up(&mddev->recovery_wait);
3246 	return len;
3247 }
3248 
3249 static struct md_sysfs_entry md_max_sync =
3250 __ATTR(sync_max, S_IRUGO|S_IWUSR, max_sync_show, max_sync_store);
3251 
3252 static ssize_t
3253 suspend_lo_show(mddev_t *mddev, char *page)
3254 {
3255 	return sprintf(page, "%llu\n", (unsigned long long)mddev->suspend_lo);
3256 }
3257 
3258 static ssize_t
3259 suspend_lo_store(mddev_t *mddev, const char *buf, size_t len)
3260 {
3261 	char *e;
3262 	unsigned long long new = simple_strtoull(buf, &e, 10);
3263 
3264 	if (mddev->pers->quiesce == NULL)
3265 		return -EINVAL;
3266 	if (buf == e || (*e && *e != '\n'))
3267 		return -EINVAL;
3268 	if (new >= mddev->suspend_hi ||
3269 	    (new > mddev->suspend_lo && new < mddev->suspend_hi)) {
3270 		mddev->suspend_lo = new;
3271 		mddev->pers->quiesce(mddev, 2);
3272 		return len;
3273 	} else
3274 		return -EINVAL;
3275 }
3276 static struct md_sysfs_entry md_suspend_lo =
3277 __ATTR(suspend_lo, S_IRUGO|S_IWUSR, suspend_lo_show, suspend_lo_store);
3278 
3279 
3280 static ssize_t
3281 suspend_hi_show(mddev_t *mddev, char *page)
3282 {
3283 	return sprintf(page, "%llu\n", (unsigned long long)mddev->suspend_hi);
3284 }
3285 
3286 static ssize_t
3287 suspend_hi_store(mddev_t *mddev, const char *buf, size_t len)
3288 {
3289 	char *e;
3290 	unsigned long long new = simple_strtoull(buf, &e, 10);
3291 
3292 	if (mddev->pers->quiesce == NULL)
3293 		return -EINVAL;
3294 	if (buf == e || (*e && *e != '\n'))
3295 		return -EINVAL;
3296 	if ((new <= mddev->suspend_lo && mddev->suspend_lo >= mddev->suspend_hi) ||
3297 	    (new > mddev->suspend_lo && new > mddev->suspend_hi)) {
3298 		mddev->suspend_hi = new;
3299 		mddev->pers->quiesce(mddev, 1);
3300 		mddev->pers->quiesce(mddev, 0);
3301 		return len;
3302 	} else
3303 		return -EINVAL;
3304 }
3305 static struct md_sysfs_entry md_suspend_hi =
3306 __ATTR(suspend_hi, S_IRUGO|S_IWUSR, suspend_hi_show, suspend_hi_store);
3307 
3308 static ssize_t
3309 reshape_position_show(mddev_t *mddev, char *page)
3310 {
3311 	if (mddev->reshape_position != MaxSector)
3312 		return sprintf(page, "%llu\n",
3313 			       (unsigned long long)mddev->reshape_position);
3314 	strcpy(page, "none\n");
3315 	return 5;
3316 }
3317 
3318 static ssize_t
3319 reshape_position_store(mddev_t *mddev, const char *buf, size_t len)
3320 {
3321 	char *e;
3322 	unsigned long long new = simple_strtoull(buf, &e, 10);
3323 	if (mddev->pers)
3324 		return -EBUSY;
3325 	if (buf == e || (*e && *e != '\n'))
3326 		return -EINVAL;
3327 	mddev->reshape_position = new;
3328 	mddev->delta_disks = 0;
3329 	mddev->new_level = mddev->level;
3330 	mddev->new_layout = mddev->layout;
3331 	mddev->new_chunk = mddev->chunk_size;
3332 	return len;
3333 }
3334 
3335 static struct md_sysfs_entry md_reshape_position =
3336 __ATTR(reshape_position, S_IRUGO|S_IWUSR, reshape_position_show,
3337        reshape_position_store);
3338 
3339 
3340 static struct attribute *md_default_attrs[] = {
3341 	&md_level.attr,
3342 	&md_layout.attr,
3343 	&md_raid_disks.attr,
3344 	&md_chunk_size.attr,
3345 	&md_size.attr,
3346 	&md_resync_start.attr,
3347 	&md_metadata.attr,
3348 	&md_new_device.attr,
3349 	&md_safe_delay.attr,
3350 	&md_array_state.attr,
3351 	&md_reshape_position.attr,
3352 	NULL,
3353 };
3354 
3355 static struct attribute *md_redundancy_attrs[] = {
3356 	&md_scan_mode.attr,
3357 	&md_mismatches.attr,
3358 	&md_sync_min.attr,
3359 	&md_sync_max.attr,
3360 	&md_sync_speed.attr,
3361 	&md_sync_force_parallel.attr,
3362 	&md_sync_completed.attr,
3363 	&md_min_sync.attr,
3364 	&md_max_sync.attr,
3365 	&md_suspend_lo.attr,
3366 	&md_suspend_hi.attr,
3367 	&md_bitmap.attr,
3368 	&md_degraded.attr,
3369 	NULL,
3370 };
3371 static struct attribute_group md_redundancy_group = {
3372 	.name = NULL,
3373 	.attrs = md_redundancy_attrs,
3374 };
3375 
3376 
3377 static ssize_t
3378 md_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
3379 {
3380 	struct md_sysfs_entry *entry = container_of(attr, struct md_sysfs_entry, attr);
3381 	mddev_t *mddev = container_of(kobj, struct mddev_s, kobj);
3382 	ssize_t rv;
3383 
3384 	if (!entry->show)
3385 		return -EIO;
3386 	rv = mddev_lock(mddev);
3387 	if (!rv) {
3388 		rv = entry->show(mddev, page);
3389 		mddev_unlock(mddev);
3390 	}
3391 	return rv;
3392 }
3393 
3394 static ssize_t
3395 md_attr_store(struct kobject *kobj, struct attribute *attr,
3396 	      const char *page, size_t length)
3397 {
3398 	struct md_sysfs_entry *entry = container_of(attr, struct md_sysfs_entry, attr);
3399 	mddev_t *mddev = container_of(kobj, struct mddev_s, kobj);
3400 	ssize_t rv;
3401 
3402 	if (!entry->store)
3403 		return -EIO;
3404 	if (!capable(CAP_SYS_ADMIN))
3405 		return -EACCES;
3406 	rv = mddev_lock(mddev);
3407 	if (!rv) {
3408 		rv = entry->store(mddev, page, length);
3409 		mddev_unlock(mddev);
3410 	}
3411 	return rv;
3412 }
3413 
3414 static void md_free(struct kobject *ko)
3415 {
3416 	mddev_t *mddev = container_of(ko, mddev_t, kobj);
3417 	kfree(mddev);
3418 }
3419 
3420 static struct sysfs_ops md_sysfs_ops = {
3421 	.show	= md_attr_show,
3422 	.store	= md_attr_store,
3423 };
3424 static struct kobj_type md_ktype = {
3425 	.release	= md_free,
3426 	.sysfs_ops	= &md_sysfs_ops,
3427 	.default_attrs	= md_default_attrs,
3428 };
3429 
3430 int mdp_major = 0;
3431 
3432 static struct kobject *md_probe(dev_t dev, int *part, void *data)
3433 {
3434 	static DEFINE_MUTEX(disks_mutex);
3435 	mddev_t *mddev = mddev_find(dev);
3436 	struct gendisk *disk;
3437 	int partitioned = (MAJOR(dev) != MD_MAJOR);
3438 	int shift = partitioned ? MdpMinorShift : 0;
3439 	int unit = MINOR(dev) >> shift;
3440 	int error;
3441 
3442 	if (!mddev)
3443 		return NULL;
3444 
3445 	mutex_lock(&disks_mutex);
3446 	if (mddev->gendisk) {
3447 		mutex_unlock(&disks_mutex);
3448 		mddev_put(mddev);
3449 		return NULL;
3450 	}
3451 	disk = alloc_disk(1 << shift);
3452 	if (!disk) {
3453 		mutex_unlock(&disks_mutex);
3454 		mddev_put(mddev);
3455 		return NULL;
3456 	}
3457 	disk->major = MAJOR(dev);
3458 	disk->first_minor = unit << shift;
3459 	if (partitioned)
3460 		sprintf(disk->disk_name, "md_d%d", unit);
3461 	else
3462 		sprintf(disk->disk_name, "md%d", unit);
3463 	disk->fops = &md_fops;
3464 	disk->private_data = mddev;
3465 	disk->queue = mddev->queue;
3466 	/* Allow extended partitions.  This makes the
3467 	 * 'mdp' device redundant, but we can really
3468 	 * remove it now.
3469 	 */
3470 	disk->flags |= GENHD_FL_EXT_DEVT;
3471 	add_disk(disk);
3472 	mddev->gendisk = disk;
3473 	error = kobject_init_and_add(&mddev->kobj, &md_ktype,
3474 				     &disk_to_dev(disk)->kobj, "%s", "md");
3475 	mutex_unlock(&disks_mutex);
3476 	if (error)
3477 		printk(KERN_WARNING "md: cannot register %s/md - name in use\n",
3478 		       disk->disk_name);
3479 	else {
3480 		kobject_uevent(&mddev->kobj, KOBJ_ADD);
3481 		mddev->sysfs_state = sysfs_get_dirent(mddev->kobj.sd, "array_state");
3482 	}
3483 	return NULL;
3484 }
3485 
3486 static void md_safemode_timeout(unsigned long data)
3487 {
3488 	mddev_t *mddev = (mddev_t *) data;
3489 
3490 	if (!atomic_read(&mddev->writes_pending)) {
3491 		mddev->safemode = 1;
3492 		if (mddev->external)
3493 			sysfs_notify_dirent(mddev->sysfs_state);
3494 	}
3495 	md_wakeup_thread(mddev->thread);
3496 }
3497 
3498 static int start_dirty_degraded;
3499 
3500 static int do_md_run(mddev_t * mddev)
3501 {
3502 	int err;
3503 	int chunk_size;
3504 	struct list_head *tmp;
3505 	mdk_rdev_t *rdev;
3506 	struct gendisk *disk;
3507 	struct mdk_personality *pers;
3508 	char b[BDEVNAME_SIZE];
3509 
3510 	if (list_empty(&mddev->disks))
3511 		/* cannot run an array with no devices.. */
3512 		return -EINVAL;
3513 
3514 	if (mddev->pers)
3515 		return -EBUSY;
3516 
3517 	/*
3518 	 * Analyze all RAID superblock(s)
3519 	 */
3520 	if (!mddev->raid_disks) {
3521 		if (!mddev->persistent)
3522 			return -EINVAL;
3523 		analyze_sbs(mddev);
3524 	}
3525 
3526 	chunk_size = mddev->chunk_size;
3527 
3528 	if (chunk_size) {
3529 		if (chunk_size > MAX_CHUNK_SIZE) {
3530 			printk(KERN_ERR "too big chunk_size: %d > %d\n",
3531 				chunk_size, MAX_CHUNK_SIZE);
3532 			return -EINVAL;
3533 		}
3534 		/*
3535 		 * chunk-size has to be a power of 2
3536 		 */
3537 		if ( (1 << ffz(~chunk_size)) != chunk_size) {
3538 			printk(KERN_ERR "chunk_size of %d not valid\n", chunk_size);
3539 			return -EINVAL;
3540 		}
3541 
3542 		/* devices must have minimum size of one chunk */
3543 		rdev_for_each(rdev, tmp, mddev) {
3544 			if (test_bit(Faulty, &rdev->flags))
3545 				continue;
3546 			if (rdev->size < chunk_size / 1024) {
3547 				printk(KERN_WARNING
3548 					"md: Dev %s smaller than chunk_size:"
3549 					" %lluk < %dk\n",
3550 					bdevname(rdev->bdev,b),
3551 					(unsigned long long)rdev->size,
3552 					chunk_size / 1024);
3553 				return -EINVAL;
3554 			}
3555 		}
3556 	}
3557 
3558 	if (mddev->level != LEVEL_NONE)
3559 		request_module("md-level-%d", mddev->level);
3560 	else if (mddev->clevel[0])
3561 		request_module("md-%s", mddev->clevel);
3562 
3563 	/*
3564 	 * Drop all container device buffers, from now on
3565 	 * the only valid external interface is through the md
3566 	 * device.
3567 	 */
3568 	rdev_for_each(rdev, tmp, mddev) {
3569 		if (test_bit(Faulty, &rdev->flags))
3570 			continue;
3571 		sync_blockdev(rdev->bdev);
3572 		invalidate_bdev(rdev->bdev);
3573 
3574 		/* perform some consistency tests on the device.
3575 		 * We don't want the data to overlap the metadata,
3576 		 * Internal Bitmap issues has handled elsewhere.
3577 		 */
3578 		if (rdev->data_offset < rdev->sb_start) {
3579 			if (mddev->size &&
3580 			    rdev->data_offset + mddev->size*2
3581 			    > rdev->sb_start) {
3582 				printk("md: %s: data overlaps metadata\n",
3583 				       mdname(mddev));
3584 				return -EINVAL;
3585 			}
3586 		} else {
3587 			if (rdev->sb_start + rdev->sb_size/512
3588 			    > rdev->data_offset) {
3589 				printk("md: %s: metadata overlaps data\n",
3590 				       mdname(mddev));
3591 				return -EINVAL;
3592 			}
3593 		}
3594 		sysfs_notify_dirent(rdev->sysfs_state);
3595 	}
3596 
3597 	md_probe(mddev->unit, NULL, NULL);
3598 	disk = mddev->gendisk;
3599 	if (!disk)
3600 		return -ENOMEM;
3601 
3602 	spin_lock(&pers_lock);
3603 	pers = find_pers(mddev->level, mddev->clevel);
3604 	if (!pers || !try_module_get(pers->owner)) {
3605 		spin_unlock(&pers_lock);
3606 		if (mddev->level != LEVEL_NONE)
3607 			printk(KERN_WARNING "md: personality for level %d is not loaded!\n",
3608 			       mddev->level);
3609 		else
3610 			printk(KERN_WARNING "md: personality for level %s is not loaded!\n",
3611 			       mddev->clevel);
3612 		return -EINVAL;
3613 	}
3614 	mddev->pers = pers;
3615 	spin_unlock(&pers_lock);
3616 	mddev->level = pers->level;
3617 	strlcpy(mddev->clevel, pers->name, sizeof(mddev->clevel));
3618 
3619 	if (mddev->reshape_position != MaxSector &&
3620 	    pers->start_reshape == NULL) {
3621 		/* This personality cannot handle reshaping... */
3622 		mddev->pers = NULL;
3623 		module_put(pers->owner);
3624 		return -EINVAL;
3625 	}
3626 
3627 	if (pers->sync_request) {
3628 		/* Warn if this is a potentially silly
3629 		 * configuration.
3630 		 */
3631 		char b[BDEVNAME_SIZE], b2[BDEVNAME_SIZE];
3632 		mdk_rdev_t *rdev2;
3633 		struct list_head *tmp2;
3634 		int warned = 0;
3635 		rdev_for_each(rdev, tmp, mddev) {
3636 			rdev_for_each(rdev2, tmp2, mddev) {
3637 				if (rdev < rdev2 &&
3638 				    rdev->bdev->bd_contains ==
3639 				    rdev2->bdev->bd_contains) {
3640 					printk(KERN_WARNING
3641 					       "%s: WARNING: %s appears to be"
3642 					       " on the same physical disk as"
3643 					       " %s.\n",
3644 					       mdname(mddev),
3645 					       bdevname(rdev->bdev,b),
3646 					       bdevname(rdev2->bdev,b2));
3647 					warned = 1;
3648 				}
3649 			}
3650 		}
3651 		if (warned)
3652 			printk(KERN_WARNING
3653 			       "True protection against single-disk"
3654 			       " failure might be compromised.\n");
3655 	}
3656 
3657 	mddev->recovery = 0;
3658 	mddev->resync_max_sectors = mddev->size << 1; /* may be over-ridden by personality */
3659 	mddev->barriers_work = 1;
3660 	mddev->ok_start_degraded = start_dirty_degraded;
3661 
3662 	if (start_readonly)
3663 		mddev->ro = 2; /* read-only, but switch on first write */
3664 
3665 	err = mddev->pers->run(mddev);
3666 	if (err)
3667 		printk(KERN_ERR "md: pers->run() failed ...\n");
3668 	else if (mddev->pers->sync_request) {
3669 		err = bitmap_create(mddev);
3670 		if (err) {
3671 			printk(KERN_ERR "%s: failed to create bitmap (%d)\n",
3672 			       mdname(mddev), err);
3673 			mddev->pers->stop(mddev);
3674 		}
3675 	}
3676 	if (err) {
3677 		module_put(mddev->pers->owner);
3678 		mddev->pers = NULL;
3679 		bitmap_destroy(mddev);
3680 		return err;
3681 	}
3682 	if (mddev->pers->sync_request) {
3683 		if (sysfs_create_group(&mddev->kobj, &md_redundancy_group))
3684 			printk(KERN_WARNING
3685 			       "md: cannot register extra attributes for %s\n",
3686 			       mdname(mddev));
3687 	} else if (mddev->ro == 2) /* auto-readonly not meaningful */
3688 		mddev->ro = 0;
3689 
3690  	atomic_set(&mddev->writes_pending,0);
3691 	mddev->safemode = 0;
3692 	mddev->safemode_timer.function = md_safemode_timeout;
3693 	mddev->safemode_timer.data = (unsigned long) mddev;
3694 	mddev->safemode_delay = (200 * HZ)/1000 +1; /* 200 msec delay */
3695 	mddev->in_sync = 1;
3696 
3697 	rdev_for_each(rdev, tmp, mddev)
3698 		if (rdev->raid_disk >= 0) {
3699 			char nm[20];
3700 			sprintf(nm, "rd%d", rdev->raid_disk);
3701 			if (sysfs_create_link(&mddev->kobj, &rdev->kobj, nm))
3702 				printk("md: cannot register %s for %s\n",
3703 				       nm, mdname(mddev));
3704 		}
3705 
3706 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
3707 
3708 	if (mddev->flags)
3709 		md_update_sb(mddev, 0);
3710 
3711 	set_capacity(disk, mddev->array_sectors);
3712 
3713 	/* If we call blk_queue_make_request here, it will
3714 	 * re-initialise max_sectors etc which may have been
3715 	 * refined inside -> run.  So just set the bits we need to set.
3716 	 * Most initialisation happended when we called
3717 	 * blk_queue_make_request(..., md_fail_request)
3718 	 * earlier.
3719 	 */
3720 	mddev->queue->queuedata = mddev;
3721 	mddev->queue->make_request_fn = mddev->pers->make_request;
3722 
3723 	/* If there is a partially-recovered drive we need to
3724 	 * start recovery here.  If we leave it to md_check_recovery,
3725 	 * it will remove the drives and not do the right thing
3726 	 */
3727 	if (mddev->degraded && !mddev->sync_thread) {
3728 		struct list_head *rtmp;
3729 		int spares = 0;
3730 		rdev_for_each(rdev, rtmp, mddev)
3731 			if (rdev->raid_disk >= 0 &&
3732 			    !test_bit(In_sync, &rdev->flags) &&
3733 			    !test_bit(Faulty, &rdev->flags))
3734 				/* complete an interrupted recovery */
3735 				spares++;
3736 		if (spares && mddev->pers->sync_request) {
3737 			mddev->recovery = 0;
3738 			set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
3739 			mddev->sync_thread = md_register_thread(md_do_sync,
3740 								mddev,
3741 								"%s_resync");
3742 			if (!mddev->sync_thread) {
3743 				printk(KERN_ERR "%s: could not start resync"
3744 				       " thread...\n",
3745 				       mdname(mddev));
3746 				/* leave the spares where they are, it shouldn't hurt */
3747 				mddev->recovery = 0;
3748 			}
3749 		}
3750 	}
3751 	md_wakeup_thread(mddev->thread);
3752 	md_wakeup_thread(mddev->sync_thread); /* possibly kick off a reshape */
3753 
3754 	mddev->changed = 1;
3755 	md_new_event(mddev);
3756 	sysfs_notify_dirent(mddev->sysfs_state);
3757 	sysfs_notify(&mddev->kobj, NULL, "sync_action");
3758 	sysfs_notify(&mddev->kobj, NULL, "degraded");
3759 	kobject_uevent(&disk_to_dev(mddev->gendisk)->kobj, KOBJ_CHANGE);
3760 	return 0;
3761 }
3762 
3763 static int restart_array(mddev_t *mddev)
3764 {
3765 	struct gendisk *disk = mddev->gendisk;
3766 
3767 	/* Complain if it has no devices */
3768 	if (list_empty(&mddev->disks))
3769 		return -ENXIO;
3770 	if (!mddev->pers)
3771 		return -EINVAL;
3772 	if (!mddev->ro)
3773 		return -EBUSY;
3774 	mddev->safemode = 0;
3775 	mddev->ro = 0;
3776 	set_disk_ro(disk, 0);
3777 	printk(KERN_INFO "md: %s switched to read-write mode.\n",
3778 		mdname(mddev));
3779 	/* Kick recovery or resync if necessary */
3780 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
3781 	md_wakeup_thread(mddev->thread);
3782 	md_wakeup_thread(mddev->sync_thread);
3783 	sysfs_notify_dirent(mddev->sysfs_state);
3784 	return 0;
3785 }
3786 
3787 /* similar to deny_write_access, but accounts for our holding a reference
3788  * to the file ourselves */
3789 static int deny_bitmap_write_access(struct file * file)
3790 {
3791 	struct inode *inode = file->f_mapping->host;
3792 
3793 	spin_lock(&inode->i_lock);
3794 	if (atomic_read(&inode->i_writecount) > 1) {
3795 		spin_unlock(&inode->i_lock);
3796 		return -ETXTBSY;
3797 	}
3798 	atomic_set(&inode->i_writecount, -1);
3799 	spin_unlock(&inode->i_lock);
3800 
3801 	return 0;
3802 }
3803 
3804 static void restore_bitmap_write_access(struct file *file)
3805 {
3806 	struct inode *inode = file->f_mapping->host;
3807 
3808 	spin_lock(&inode->i_lock);
3809 	atomic_set(&inode->i_writecount, 1);
3810 	spin_unlock(&inode->i_lock);
3811 }
3812 
3813 /* mode:
3814  *   0 - completely stop and dis-assemble array
3815  *   1 - switch to readonly
3816  *   2 - stop but do not disassemble array
3817  */
3818 static int do_md_stop(mddev_t * mddev, int mode, int is_open)
3819 {
3820 	int err = 0;
3821 	struct gendisk *disk = mddev->gendisk;
3822 
3823 	if (atomic_read(&mddev->openers) > is_open) {
3824 		printk("md: %s still in use.\n",mdname(mddev));
3825 		return -EBUSY;
3826 	}
3827 
3828 	if (mddev->pers) {
3829 
3830 		if (mddev->sync_thread) {
3831 			set_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
3832 			set_bit(MD_RECOVERY_INTR, &mddev->recovery);
3833 			md_unregister_thread(mddev->sync_thread);
3834 			mddev->sync_thread = NULL;
3835 		}
3836 
3837 		del_timer_sync(&mddev->safemode_timer);
3838 
3839 		switch(mode) {
3840 		case 1: /* readonly */
3841 			err  = -ENXIO;
3842 			if (mddev->ro==1)
3843 				goto out;
3844 			mddev->ro = 1;
3845 			break;
3846 		case 0: /* disassemble */
3847 		case 2: /* stop */
3848 			bitmap_flush(mddev);
3849 			md_super_wait(mddev);
3850 			if (mddev->ro)
3851 				set_disk_ro(disk, 0);
3852 			blk_queue_make_request(mddev->queue, md_fail_request);
3853 			mddev->pers->stop(mddev);
3854 			mddev->queue->merge_bvec_fn = NULL;
3855 			mddev->queue->unplug_fn = NULL;
3856 			mddev->queue->backing_dev_info.congested_fn = NULL;
3857 			if (mddev->pers->sync_request)
3858 				sysfs_remove_group(&mddev->kobj, &md_redundancy_group);
3859 
3860 			module_put(mddev->pers->owner);
3861 			mddev->pers = NULL;
3862 			/* tell userspace to handle 'inactive' */
3863 			sysfs_notify_dirent(mddev->sysfs_state);
3864 
3865 			set_capacity(disk, 0);
3866 			mddev->changed = 1;
3867 
3868 			if (mddev->ro)
3869 				mddev->ro = 0;
3870 		}
3871 		if (!mddev->in_sync || mddev->flags) {
3872 			/* mark array as shutdown cleanly */
3873 			mddev->in_sync = 1;
3874 			md_update_sb(mddev, 1);
3875 		}
3876 		if (mode == 1)
3877 			set_disk_ro(disk, 1);
3878 		clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
3879 	}
3880 
3881 	/*
3882 	 * Free resources if final stop
3883 	 */
3884 	if (mode == 0) {
3885 		mdk_rdev_t *rdev;
3886 		struct list_head *tmp;
3887 
3888 		printk(KERN_INFO "md: %s stopped.\n", mdname(mddev));
3889 
3890 		bitmap_destroy(mddev);
3891 		if (mddev->bitmap_file) {
3892 			restore_bitmap_write_access(mddev->bitmap_file);
3893 			fput(mddev->bitmap_file);
3894 			mddev->bitmap_file = NULL;
3895 		}
3896 		mddev->bitmap_offset = 0;
3897 
3898 		rdev_for_each(rdev, tmp, mddev)
3899 			if (rdev->raid_disk >= 0) {
3900 				char nm[20];
3901 				sprintf(nm, "rd%d", rdev->raid_disk);
3902 				sysfs_remove_link(&mddev->kobj, nm);
3903 			}
3904 
3905 		/* make sure all md_delayed_delete calls have finished */
3906 		flush_scheduled_work();
3907 
3908 		export_array(mddev);
3909 
3910 		mddev->array_sectors = 0;
3911 		mddev->size = 0;
3912 		mddev->raid_disks = 0;
3913 		mddev->recovery_cp = 0;
3914 		mddev->resync_min = 0;
3915 		mddev->resync_max = MaxSector;
3916 		mddev->reshape_position = MaxSector;
3917 		mddev->external = 0;
3918 		mddev->persistent = 0;
3919 		mddev->level = LEVEL_NONE;
3920 		mddev->clevel[0] = 0;
3921 		mddev->flags = 0;
3922 		mddev->ro = 0;
3923 		mddev->metadata_type[0] = 0;
3924 		mddev->chunk_size = 0;
3925 		mddev->ctime = mddev->utime = 0;
3926 		mddev->layout = 0;
3927 		mddev->max_disks = 0;
3928 		mddev->events = 0;
3929 		mddev->delta_disks = 0;
3930 		mddev->new_level = LEVEL_NONE;
3931 		mddev->new_layout = 0;
3932 		mddev->new_chunk = 0;
3933 		mddev->curr_resync = 0;
3934 		mddev->resync_mismatches = 0;
3935 		mddev->suspend_lo = mddev->suspend_hi = 0;
3936 		mddev->sync_speed_min = mddev->sync_speed_max = 0;
3937 		mddev->recovery = 0;
3938 		mddev->in_sync = 0;
3939 		mddev->changed = 0;
3940 		mddev->degraded = 0;
3941 		mddev->barriers_work = 0;
3942 		mddev->safemode = 0;
3943 		kobject_uevent(&disk_to_dev(mddev->gendisk)->kobj, KOBJ_CHANGE);
3944 
3945 	} else if (mddev->pers)
3946 		printk(KERN_INFO "md: %s switched to read-only mode.\n",
3947 			mdname(mddev));
3948 	err = 0;
3949 	md_new_event(mddev);
3950 	sysfs_notify_dirent(mddev->sysfs_state);
3951 out:
3952 	return err;
3953 }
3954 
3955 #ifndef MODULE
3956 static void autorun_array(mddev_t *mddev)
3957 {
3958 	mdk_rdev_t *rdev;
3959 	struct list_head *tmp;
3960 	int err;
3961 
3962 	if (list_empty(&mddev->disks))
3963 		return;
3964 
3965 	printk(KERN_INFO "md: running: ");
3966 
3967 	rdev_for_each(rdev, tmp, mddev) {
3968 		char b[BDEVNAME_SIZE];
3969 		printk("<%s>", bdevname(rdev->bdev,b));
3970 	}
3971 	printk("\n");
3972 
3973 	err = do_md_run(mddev);
3974 	if (err) {
3975 		printk(KERN_WARNING "md: do_md_run() returned %d\n", err);
3976 		do_md_stop(mddev, 0, 0);
3977 	}
3978 }
3979 
3980 /*
3981  * lets try to run arrays based on all disks that have arrived
3982  * until now. (those are in pending_raid_disks)
3983  *
3984  * the method: pick the first pending disk, collect all disks with
3985  * the same UUID, remove all from the pending list and put them into
3986  * the 'same_array' list. Then order this list based on superblock
3987  * update time (freshest comes first), kick out 'old' disks and
3988  * compare superblocks. If everything's fine then run it.
3989  *
3990  * If "unit" is allocated, then bump its reference count
3991  */
3992 static void autorun_devices(int part)
3993 {
3994 	struct list_head *tmp;
3995 	mdk_rdev_t *rdev0, *rdev;
3996 	mddev_t *mddev;
3997 	char b[BDEVNAME_SIZE];
3998 
3999 	printk(KERN_INFO "md: autorun ...\n");
4000 	while (!list_empty(&pending_raid_disks)) {
4001 		int unit;
4002 		dev_t dev;
4003 		LIST_HEAD(candidates);
4004 		rdev0 = list_entry(pending_raid_disks.next,
4005 					 mdk_rdev_t, same_set);
4006 
4007 		printk(KERN_INFO "md: considering %s ...\n",
4008 			bdevname(rdev0->bdev,b));
4009 		INIT_LIST_HEAD(&candidates);
4010 		rdev_for_each_list(rdev, tmp, pending_raid_disks)
4011 			if (super_90_load(rdev, rdev0, 0) >= 0) {
4012 				printk(KERN_INFO "md:  adding %s ...\n",
4013 					bdevname(rdev->bdev,b));
4014 				list_move(&rdev->same_set, &candidates);
4015 			}
4016 		/*
4017 		 * now we have a set of devices, with all of them having
4018 		 * mostly sane superblocks. It's time to allocate the
4019 		 * mddev.
4020 		 */
4021 		if (part) {
4022 			dev = MKDEV(mdp_major,
4023 				    rdev0->preferred_minor << MdpMinorShift);
4024 			unit = MINOR(dev) >> MdpMinorShift;
4025 		} else {
4026 			dev = MKDEV(MD_MAJOR, rdev0->preferred_minor);
4027 			unit = MINOR(dev);
4028 		}
4029 		if (rdev0->preferred_minor != unit) {
4030 			printk(KERN_INFO "md: unit number in %s is bad: %d\n",
4031 			       bdevname(rdev0->bdev, b), rdev0->preferred_minor);
4032 			break;
4033 		}
4034 
4035 		md_probe(dev, NULL, NULL);
4036 		mddev = mddev_find(dev);
4037 		if (!mddev || !mddev->gendisk) {
4038 			if (mddev)
4039 				mddev_put(mddev);
4040 			printk(KERN_ERR
4041 				"md: cannot allocate memory for md drive.\n");
4042 			break;
4043 		}
4044 		if (mddev_lock(mddev))
4045 			printk(KERN_WARNING "md: %s locked, cannot run\n",
4046 			       mdname(mddev));
4047 		else if (mddev->raid_disks || mddev->major_version
4048 			 || !list_empty(&mddev->disks)) {
4049 			printk(KERN_WARNING
4050 				"md: %s already running, cannot run %s\n",
4051 				mdname(mddev), bdevname(rdev0->bdev,b));
4052 			mddev_unlock(mddev);
4053 		} else {
4054 			printk(KERN_INFO "md: created %s\n", mdname(mddev));
4055 			mddev->persistent = 1;
4056 			rdev_for_each_list(rdev, tmp, candidates) {
4057 				list_del_init(&rdev->same_set);
4058 				if (bind_rdev_to_array(rdev, mddev))
4059 					export_rdev(rdev);
4060 			}
4061 			autorun_array(mddev);
4062 			mddev_unlock(mddev);
4063 		}
4064 		/* on success, candidates will be empty, on error
4065 		 * it won't...
4066 		 */
4067 		rdev_for_each_list(rdev, tmp, candidates) {
4068 			list_del_init(&rdev->same_set);
4069 			export_rdev(rdev);
4070 		}
4071 		mddev_put(mddev);
4072 	}
4073 	printk(KERN_INFO "md: ... autorun DONE.\n");
4074 }
4075 #endif /* !MODULE */
4076 
4077 static int get_version(void __user * arg)
4078 {
4079 	mdu_version_t ver;
4080 
4081 	ver.major = MD_MAJOR_VERSION;
4082 	ver.minor = MD_MINOR_VERSION;
4083 	ver.patchlevel = MD_PATCHLEVEL_VERSION;
4084 
4085 	if (copy_to_user(arg, &ver, sizeof(ver)))
4086 		return -EFAULT;
4087 
4088 	return 0;
4089 }
4090 
4091 static int get_array_info(mddev_t * mddev, void __user * arg)
4092 {
4093 	mdu_array_info_t info;
4094 	int nr,working,active,failed,spare;
4095 	mdk_rdev_t *rdev;
4096 	struct list_head *tmp;
4097 
4098 	nr=working=active=failed=spare=0;
4099 	rdev_for_each(rdev, tmp, mddev) {
4100 		nr++;
4101 		if (test_bit(Faulty, &rdev->flags))
4102 			failed++;
4103 		else {
4104 			working++;
4105 			if (test_bit(In_sync, &rdev->flags))
4106 				active++;
4107 			else
4108 				spare++;
4109 		}
4110 	}
4111 
4112 	info.major_version = mddev->major_version;
4113 	info.minor_version = mddev->minor_version;
4114 	info.patch_version = MD_PATCHLEVEL_VERSION;
4115 	info.ctime         = mddev->ctime;
4116 	info.level         = mddev->level;
4117 	info.size          = mddev->size;
4118 	if (info.size != mddev->size) /* overflow */
4119 		info.size = -1;
4120 	info.nr_disks      = nr;
4121 	info.raid_disks    = mddev->raid_disks;
4122 	info.md_minor      = mddev->md_minor;
4123 	info.not_persistent= !mddev->persistent;
4124 
4125 	info.utime         = mddev->utime;
4126 	info.state         = 0;
4127 	if (mddev->in_sync)
4128 		info.state = (1<<MD_SB_CLEAN);
4129 	if (mddev->bitmap && mddev->bitmap_offset)
4130 		info.state = (1<<MD_SB_BITMAP_PRESENT);
4131 	info.active_disks  = active;
4132 	info.working_disks = working;
4133 	info.failed_disks  = failed;
4134 	info.spare_disks   = spare;
4135 
4136 	info.layout        = mddev->layout;
4137 	info.chunk_size    = mddev->chunk_size;
4138 
4139 	if (copy_to_user(arg, &info, sizeof(info)))
4140 		return -EFAULT;
4141 
4142 	return 0;
4143 }
4144 
4145 static int get_bitmap_file(mddev_t * mddev, void __user * arg)
4146 {
4147 	mdu_bitmap_file_t *file = NULL; /* too big for stack allocation */
4148 	char *ptr, *buf = NULL;
4149 	int err = -ENOMEM;
4150 
4151 	if (md_allow_write(mddev))
4152 		file = kmalloc(sizeof(*file), GFP_NOIO);
4153 	else
4154 		file = kmalloc(sizeof(*file), GFP_KERNEL);
4155 
4156 	if (!file)
4157 		goto out;
4158 
4159 	/* bitmap disabled, zero the first byte and copy out */
4160 	if (!mddev->bitmap || !mddev->bitmap->file) {
4161 		file->pathname[0] = '\0';
4162 		goto copy_out;
4163 	}
4164 
4165 	buf = kmalloc(sizeof(file->pathname), GFP_KERNEL);
4166 	if (!buf)
4167 		goto out;
4168 
4169 	ptr = d_path(&mddev->bitmap->file->f_path, buf, sizeof(file->pathname));
4170 	if (IS_ERR(ptr))
4171 		goto out;
4172 
4173 	strcpy(file->pathname, ptr);
4174 
4175 copy_out:
4176 	err = 0;
4177 	if (copy_to_user(arg, file, sizeof(*file)))
4178 		err = -EFAULT;
4179 out:
4180 	kfree(buf);
4181 	kfree(file);
4182 	return err;
4183 }
4184 
4185 static int get_disk_info(mddev_t * mddev, void __user * arg)
4186 {
4187 	mdu_disk_info_t info;
4188 	mdk_rdev_t *rdev;
4189 
4190 	if (copy_from_user(&info, arg, sizeof(info)))
4191 		return -EFAULT;
4192 
4193 	rdev = find_rdev_nr(mddev, info.number);
4194 	if (rdev) {
4195 		info.major = MAJOR(rdev->bdev->bd_dev);
4196 		info.minor = MINOR(rdev->bdev->bd_dev);
4197 		info.raid_disk = rdev->raid_disk;
4198 		info.state = 0;
4199 		if (test_bit(Faulty, &rdev->flags))
4200 			info.state |= (1<<MD_DISK_FAULTY);
4201 		else if (test_bit(In_sync, &rdev->flags)) {
4202 			info.state |= (1<<MD_DISK_ACTIVE);
4203 			info.state |= (1<<MD_DISK_SYNC);
4204 		}
4205 		if (test_bit(WriteMostly, &rdev->flags))
4206 			info.state |= (1<<MD_DISK_WRITEMOSTLY);
4207 	} else {
4208 		info.major = info.minor = 0;
4209 		info.raid_disk = -1;
4210 		info.state = (1<<MD_DISK_REMOVED);
4211 	}
4212 
4213 	if (copy_to_user(arg, &info, sizeof(info)))
4214 		return -EFAULT;
4215 
4216 	return 0;
4217 }
4218 
4219 static int add_new_disk(mddev_t * mddev, mdu_disk_info_t *info)
4220 {
4221 	char b[BDEVNAME_SIZE], b2[BDEVNAME_SIZE];
4222 	mdk_rdev_t *rdev;
4223 	dev_t dev = MKDEV(info->major,info->minor);
4224 
4225 	if (info->major != MAJOR(dev) || info->minor != MINOR(dev))
4226 		return -EOVERFLOW;
4227 
4228 	if (!mddev->raid_disks) {
4229 		int err;
4230 		/* expecting a device which has a superblock */
4231 		rdev = md_import_device(dev, mddev->major_version, mddev->minor_version);
4232 		if (IS_ERR(rdev)) {
4233 			printk(KERN_WARNING
4234 				"md: md_import_device returned %ld\n",
4235 				PTR_ERR(rdev));
4236 			return PTR_ERR(rdev);
4237 		}
4238 		if (!list_empty(&mddev->disks)) {
4239 			mdk_rdev_t *rdev0 = list_entry(mddev->disks.next,
4240 							mdk_rdev_t, same_set);
4241 			int err = super_types[mddev->major_version]
4242 				.load_super(rdev, rdev0, mddev->minor_version);
4243 			if (err < 0) {
4244 				printk(KERN_WARNING
4245 					"md: %s has different UUID to %s\n",
4246 					bdevname(rdev->bdev,b),
4247 					bdevname(rdev0->bdev,b2));
4248 				export_rdev(rdev);
4249 				return -EINVAL;
4250 			}
4251 		}
4252 		err = bind_rdev_to_array(rdev, mddev);
4253 		if (err)
4254 			export_rdev(rdev);
4255 		return err;
4256 	}
4257 
4258 	/*
4259 	 * add_new_disk can be used once the array is assembled
4260 	 * to add "hot spares".  They must already have a superblock
4261 	 * written
4262 	 */
4263 	if (mddev->pers) {
4264 		int err;
4265 		if (!mddev->pers->hot_add_disk) {
4266 			printk(KERN_WARNING
4267 				"%s: personality does not support diskops!\n",
4268 			       mdname(mddev));
4269 			return -EINVAL;
4270 		}
4271 		if (mddev->persistent)
4272 			rdev = md_import_device(dev, mddev->major_version,
4273 						mddev->minor_version);
4274 		else
4275 			rdev = md_import_device(dev, -1, -1);
4276 		if (IS_ERR(rdev)) {
4277 			printk(KERN_WARNING
4278 				"md: md_import_device returned %ld\n",
4279 				PTR_ERR(rdev));
4280 			return PTR_ERR(rdev);
4281 		}
4282 		/* set save_raid_disk if appropriate */
4283 		if (!mddev->persistent) {
4284 			if (info->state & (1<<MD_DISK_SYNC)  &&
4285 			    info->raid_disk < mddev->raid_disks)
4286 				rdev->raid_disk = info->raid_disk;
4287 			else
4288 				rdev->raid_disk = -1;
4289 		} else
4290 			super_types[mddev->major_version].
4291 				validate_super(mddev, rdev);
4292 		rdev->saved_raid_disk = rdev->raid_disk;
4293 
4294 		clear_bit(In_sync, &rdev->flags); /* just to be sure */
4295 		if (info->state & (1<<MD_DISK_WRITEMOSTLY))
4296 			set_bit(WriteMostly, &rdev->flags);
4297 
4298 		rdev->raid_disk = -1;
4299 		err = bind_rdev_to_array(rdev, mddev);
4300 		if (!err && !mddev->pers->hot_remove_disk) {
4301 			/* If there is hot_add_disk but no hot_remove_disk
4302 			 * then added disks for geometry changes,
4303 			 * and should be added immediately.
4304 			 */
4305 			super_types[mddev->major_version].
4306 				validate_super(mddev, rdev);
4307 			err = mddev->pers->hot_add_disk(mddev, rdev);
4308 			if (err)
4309 				unbind_rdev_from_array(rdev);
4310 		}
4311 		if (err)
4312 			export_rdev(rdev);
4313 		else
4314 			sysfs_notify_dirent(rdev->sysfs_state);
4315 
4316 		md_update_sb(mddev, 1);
4317 		if (mddev->degraded)
4318 			set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
4319 		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
4320 		md_wakeup_thread(mddev->thread);
4321 		return err;
4322 	}
4323 
4324 	/* otherwise, add_new_disk is only allowed
4325 	 * for major_version==0 superblocks
4326 	 */
4327 	if (mddev->major_version != 0) {
4328 		printk(KERN_WARNING "%s: ADD_NEW_DISK not supported\n",
4329 		       mdname(mddev));
4330 		return -EINVAL;
4331 	}
4332 
4333 	if (!(info->state & (1<<MD_DISK_FAULTY))) {
4334 		int err;
4335 		rdev = md_import_device(dev, -1, 0);
4336 		if (IS_ERR(rdev)) {
4337 			printk(KERN_WARNING
4338 				"md: error, md_import_device() returned %ld\n",
4339 				PTR_ERR(rdev));
4340 			return PTR_ERR(rdev);
4341 		}
4342 		rdev->desc_nr = info->number;
4343 		if (info->raid_disk < mddev->raid_disks)
4344 			rdev->raid_disk = info->raid_disk;
4345 		else
4346 			rdev->raid_disk = -1;
4347 
4348 		if (rdev->raid_disk < mddev->raid_disks)
4349 			if (info->state & (1<<MD_DISK_SYNC))
4350 				set_bit(In_sync, &rdev->flags);
4351 
4352 		if (info->state & (1<<MD_DISK_WRITEMOSTLY))
4353 			set_bit(WriteMostly, &rdev->flags);
4354 
4355 		if (!mddev->persistent) {
4356 			printk(KERN_INFO "md: nonpersistent superblock ...\n");
4357 			rdev->sb_start = rdev->bdev->bd_inode->i_size / 512;
4358 		} else
4359 			rdev->sb_start = calc_dev_sboffset(rdev->bdev);
4360 		rdev->size = calc_num_sectors(rdev, mddev->chunk_size) / 2;
4361 
4362 		err = bind_rdev_to_array(rdev, mddev);
4363 		if (err) {
4364 			export_rdev(rdev);
4365 			return err;
4366 		}
4367 	}
4368 
4369 	return 0;
4370 }
4371 
4372 static int hot_remove_disk(mddev_t * mddev, dev_t dev)
4373 {
4374 	char b[BDEVNAME_SIZE];
4375 	mdk_rdev_t *rdev;
4376 
4377 	rdev = find_rdev(mddev, dev);
4378 	if (!rdev)
4379 		return -ENXIO;
4380 
4381 	if (rdev->raid_disk >= 0)
4382 		goto busy;
4383 
4384 	kick_rdev_from_array(rdev);
4385 	md_update_sb(mddev, 1);
4386 	md_new_event(mddev);
4387 
4388 	return 0;
4389 busy:
4390 	printk(KERN_WARNING "md: cannot remove active disk %s from %s ...\n",
4391 		bdevname(rdev->bdev,b), mdname(mddev));
4392 	return -EBUSY;
4393 }
4394 
4395 static int hot_add_disk(mddev_t * mddev, dev_t dev)
4396 {
4397 	char b[BDEVNAME_SIZE];
4398 	int err;
4399 	mdk_rdev_t *rdev;
4400 
4401 	if (!mddev->pers)
4402 		return -ENODEV;
4403 
4404 	if (mddev->major_version != 0) {
4405 		printk(KERN_WARNING "%s: HOT_ADD may only be used with"
4406 			" version-0 superblocks.\n",
4407 			mdname(mddev));
4408 		return -EINVAL;
4409 	}
4410 	if (!mddev->pers->hot_add_disk) {
4411 		printk(KERN_WARNING
4412 			"%s: personality does not support diskops!\n",
4413 			mdname(mddev));
4414 		return -EINVAL;
4415 	}
4416 
4417 	rdev = md_import_device(dev, -1, 0);
4418 	if (IS_ERR(rdev)) {
4419 		printk(KERN_WARNING
4420 			"md: error, md_import_device() returned %ld\n",
4421 			PTR_ERR(rdev));
4422 		return -EINVAL;
4423 	}
4424 
4425 	if (mddev->persistent)
4426 		rdev->sb_start = calc_dev_sboffset(rdev->bdev);
4427 	else
4428 		rdev->sb_start = rdev->bdev->bd_inode->i_size / 512;
4429 
4430 	rdev->size = calc_num_sectors(rdev, mddev->chunk_size) / 2;
4431 
4432 	if (test_bit(Faulty, &rdev->flags)) {
4433 		printk(KERN_WARNING
4434 			"md: can not hot-add faulty %s disk to %s!\n",
4435 			bdevname(rdev->bdev,b), mdname(mddev));
4436 		err = -EINVAL;
4437 		goto abort_export;
4438 	}
4439 	clear_bit(In_sync, &rdev->flags);
4440 	rdev->desc_nr = -1;
4441 	rdev->saved_raid_disk = -1;
4442 	err = bind_rdev_to_array(rdev, mddev);
4443 	if (err)
4444 		goto abort_export;
4445 
4446 	/*
4447 	 * The rest should better be atomic, we can have disk failures
4448 	 * noticed in interrupt contexts ...
4449 	 */
4450 
4451 	if (rdev->desc_nr == mddev->max_disks) {
4452 		printk(KERN_WARNING "%s: can not hot-add to full array!\n",
4453 			mdname(mddev));
4454 		err = -EBUSY;
4455 		goto abort_unbind_export;
4456 	}
4457 
4458 	rdev->raid_disk = -1;
4459 
4460 	md_update_sb(mddev, 1);
4461 
4462 	/*
4463 	 * Kick recovery, maybe this spare has to be added to the
4464 	 * array immediately.
4465 	 */
4466 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
4467 	md_wakeup_thread(mddev->thread);
4468 	md_new_event(mddev);
4469 	return 0;
4470 
4471 abort_unbind_export:
4472 	unbind_rdev_from_array(rdev);
4473 
4474 abort_export:
4475 	export_rdev(rdev);
4476 	return err;
4477 }
4478 
4479 static int set_bitmap_file(mddev_t *mddev, int fd)
4480 {
4481 	int err;
4482 
4483 	if (mddev->pers) {
4484 		if (!mddev->pers->quiesce)
4485 			return -EBUSY;
4486 		if (mddev->recovery || mddev->sync_thread)
4487 			return -EBUSY;
4488 		/* we should be able to change the bitmap.. */
4489 	}
4490 
4491 
4492 	if (fd >= 0) {
4493 		if (mddev->bitmap)
4494 			return -EEXIST; /* cannot add when bitmap is present */
4495 		mddev->bitmap_file = fget(fd);
4496 
4497 		if (mddev->bitmap_file == NULL) {
4498 			printk(KERN_ERR "%s: error: failed to get bitmap file\n",
4499 			       mdname(mddev));
4500 			return -EBADF;
4501 		}
4502 
4503 		err = deny_bitmap_write_access(mddev->bitmap_file);
4504 		if (err) {
4505 			printk(KERN_ERR "%s: error: bitmap file is already in use\n",
4506 			       mdname(mddev));
4507 			fput(mddev->bitmap_file);
4508 			mddev->bitmap_file = NULL;
4509 			return err;
4510 		}
4511 		mddev->bitmap_offset = 0; /* file overrides offset */
4512 	} else if (mddev->bitmap == NULL)
4513 		return -ENOENT; /* cannot remove what isn't there */
4514 	err = 0;
4515 	if (mddev->pers) {
4516 		mddev->pers->quiesce(mddev, 1);
4517 		if (fd >= 0)
4518 			err = bitmap_create(mddev);
4519 		if (fd < 0 || err) {
4520 			bitmap_destroy(mddev);
4521 			fd = -1; /* make sure to put the file */
4522 		}
4523 		mddev->pers->quiesce(mddev, 0);
4524 	}
4525 	if (fd < 0) {
4526 		if (mddev->bitmap_file) {
4527 			restore_bitmap_write_access(mddev->bitmap_file);
4528 			fput(mddev->bitmap_file);
4529 		}
4530 		mddev->bitmap_file = NULL;
4531 	}
4532 
4533 	return err;
4534 }
4535 
4536 /*
4537  * set_array_info is used two different ways
4538  * The original usage is when creating a new array.
4539  * In this usage, raid_disks is > 0 and it together with
4540  *  level, size, not_persistent,layout,chunksize determine the
4541  *  shape of the array.
4542  *  This will always create an array with a type-0.90.0 superblock.
4543  * The newer usage is when assembling an array.
4544  *  In this case raid_disks will be 0, and the major_version field is
4545  *  use to determine which style super-blocks are to be found on the devices.
4546  *  The minor and patch _version numbers are also kept incase the
4547  *  super_block handler wishes to interpret them.
4548  */
4549 static int set_array_info(mddev_t * mddev, mdu_array_info_t *info)
4550 {
4551 
4552 	if (info->raid_disks == 0) {
4553 		/* just setting version number for superblock loading */
4554 		if (info->major_version < 0 ||
4555 		    info->major_version >= ARRAY_SIZE(super_types) ||
4556 		    super_types[info->major_version].name == NULL) {
4557 			/* maybe try to auto-load a module? */
4558 			printk(KERN_INFO
4559 				"md: superblock version %d not known\n",
4560 				info->major_version);
4561 			return -EINVAL;
4562 		}
4563 		mddev->major_version = info->major_version;
4564 		mddev->minor_version = info->minor_version;
4565 		mddev->patch_version = info->patch_version;
4566 		mddev->persistent = !info->not_persistent;
4567 		return 0;
4568 	}
4569 	mddev->major_version = MD_MAJOR_VERSION;
4570 	mddev->minor_version = MD_MINOR_VERSION;
4571 	mddev->patch_version = MD_PATCHLEVEL_VERSION;
4572 	mddev->ctime         = get_seconds();
4573 
4574 	mddev->level         = info->level;
4575 	mddev->clevel[0]     = 0;
4576 	mddev->size          = info->size;
4577 	mddev->raid_disks    = info->raid_disks;
4578 	/* don't set md_minor, it is determined by which /dev/md* was
4579 	 * openned
4580 	 */
4581 	if (info->state & (1<<MD_SB_CLEAN))
4582 		mddev->recovery_cp = MaxSector;
4583 	else
4584 		mddev->recovery_cp = 0;
4585 	mddev->persistent    = ! info->not_persistent;
4586 	mddev->external	     = 0;
4587 
4588 	mddev->layout        = info->layout;
4589 	mddev->chunk_size    = info->chunk_size;
4590 
4591 	mddev->max_disks     = MD_SB_DISKS;
4592 
4593 	if (mddev->persistent)
4594 		mddev->flags         = 0;
4595 	set_bit(MD_CHANGE_DEVS, &mddev->flags);
4596 
4597 	mddev->default_bitmap_offset = MD_SB_BYTES >> 9;
4598 	mddev->bitmap_offset = 0;
4599 
4600 	mddev->reshape_position = MaxSector;
4601 
4602 	/*
4603 	 * Generate a 128 bit UUID
4604 	 */
4605 	get_random_bytes(mddev->uuid, 16);
4606 
4607 	mddev->new_level = mddev->level;
4608 	mddev->new_chunk = mddev->chunk_size;
4609 	mddev->new_layout = mddev->layout;
4610 	mddev->delta_disks = 0;
4611 
4612 	return 0;
4613 }
4614 
4615 static int update_size(mddev_t *mddev, sector_t num_sectors)
4616 {
4617 	mdk_rdev_t * rdev;
4618 	int rv;
4619 	struct list_head *tmp;
4620 	int fit = (num_sectors == 0);
4621 
4622 	if (mddev->pers->resize == NULL)
4623 		return -EINVAL;
4624 	/* The "num_sectors" is the number of sectors of each device that
4625 	 * is used.  This can only make sense for arrays with redundancy.
4626 	 * linear and raid0 always use whatever space is available. We can only
4627 	 * consider changing this number if no resync or reconstruction is
4628 	 * happening, and if the new size is acceptable. It must fit before the
4629 	 * sb_start or, if that is <data_offset, it must fit before the size
4630 	 * of each device.  If num_sectors is zero, we find the largest size
4631 	 * that fits.
4632 
4633 	 */
4634 	if (mddev->sync_thread)
4635 		return -EBUSY;
4636 	if (mddev->bitmap)
4637 		/* Sorry, cannot grow a bitmap yet, just remove it,
4638 		 * grow, and re-add.
4639 		 */
4640 		return -EBUSY;
4641 	rdev_for_each(rdev, tmp, mddev) {
4642 		sector_t avail;
4643 		avail = rdev->size * 2;
4644 
4645 		if (fit && (num_sectors == 0 || num_sectors > avail))
4646 			num_sectors = avail;
4647 		if (avail < num_sectors)
4648 			return -ENOSPC;
4649 	}
4650 	rv = mddev->pers->resize(mddev, num_sectors);
4651 	if (!rv) {
4652 		struct block_device *bdev;
4653 
4654 		bdev = bdget_disk(mddev->gendisk, 0);
4655 		if (bdev) {
4656 			mutex_lock(&bdev->bd_inode->i_mutex);
4657 			i_size_write(bdev->bd_inode,
4658 				     (loff_t)mddev->array_sectors << 9);
4659 			mutex_unlock(&bdev->bd_inode->i_mutex);
4660 			bdput(bdev);
4661 		}
4662 	}
4663 	return rv;
4664 }
4665 
4666 static int update_raid_disks(mddev_t *mddev, int raid_disks)
4667 {
4668 	int rv;
4669 	/* change the number of raid disks */
4670 	if (mddev->pers->check_reshape == NULL)
4671 		return -EINVAL;
4672 	if (raid_disks <= 0 ||
4673 	    raid_disks >= mddev->max_disks)
4674 		return -EINVAL;
4675 	if (mddev->sync_thread || mddev->reshape_position != MaxSector)
4676 		return -EBUSY;
4677 	mddev->delta_disks = raid_disks - mddev->raid_disks;
4678 
4679 	rv = mddev->pers->check_reshape(mddev);
4680 	return rv;
4681 }
4682 
4683 
4684 /*
4685  * update_array_info is used to change the configuration of an
4686  * on-line array.
4687  * The version, ctime,level,size,raid_disks,not_persistent, layout,chunk_size
4688  * fields in the info are checked against the array.
4689  * Any differences that cannot be handled will cause an error.
4690  * Normally, only one change can be managed at a time.
4691  */
4692 static int update_array_info(mddev_t *mddev, mdu_array_info_t *info)
4693 {
4694 	int rv = 0;
4695 	int cnt = 0;
4696 	int state = 0;
4697 
4698 	/* calculate expected state,ignoring low bits */
4699 	if (mddev->bitmap && mddev->bitmap_offset)
4700 		state |= (1 << MD_SB_BITMAP_PRESENT);
4701 
4702 	if (mddev->major_version != info->major_version ||
4703 	    mddev->minor_version != info->minor_version ||
4704 /*	    mddev->patch_version != info->patch_version || */
4705 	    mddev->ctime         != info->ctime         ||
4706 	    mddev->level         != info->level         ||
4707 /*	    mddev->layout        != info->layout        || */
4708 	    !mddev->persistent	 != info->not_persistent||
4709 	    mddev->chunk_size    != info->chunk_size    ||
4710 	    /* ignore bottom 8 bits of state, and allow SB_BITMAP_PRESENT to change */
4711 	    ((state^info->state) & 0xfffffe00)
4712 		)
4713 		return -EINVAL;
4714 	/* Check there is only one change */
4715 	if (info->size >= 0 && mddev->size != info->size) cnt++;
4716 	if (mddev->raid_disks != info->raid_disks) cnt++;
4717 	if (mddev->layout != info->layout) cnt++;
4718 	if ((state ^ info->state) & (1<<MD_SB_BITMAP_PRESENT)) cnt++;
4719 	if (cnt == 0) return 0;
4720 	if (cnt > 1) return -EINVAL;
4721 
4722 	if (mddev->layout != info->layout) {
4723 		/* Change layout
4724 		 * we don't need to do anything at the md level, the
4725 		 * personality will take care of it all.
4726 		 */
4727 		if (mddev->pers->reconfig == NULL)
4728 			return -EINVAL;
4729 		else
4730 			return mddev->pers->reconfig(mddev, info->layout, -1);
4731 	}
4732 	if (info->size >= 0 && mddev->size != info->size)
4733 		rv = update_size(mddev, (sector_t)info->size * 2);
4734 
4735 	if (mddev->raid_disks    != info->raid_disks)
4736 		rv = update_raid_disks(mddev, info->raid_disks);
4737 
4738 	if ((state ^ info->state) & (1<<MD_SB_BITMAP_PRESENT)) {
4739 		if (mddev->pers->quiesce == NULL)
4740 			return -EINVAL;
4741 		if (mddev->recovery || mddev->sync_thread)
4742 			return -EBUSY;
4743 		if (info->state & (1<<MD_SB_BITMAP_PRESENT)) {
4744 			/* add the bitmap */
4745 			if (mddev->bitmap)
4746 				return -EEXIST;
4747 			if (mddev->default_bitmap_offset == 0)
4748 				return -EINVAL;
4749 			mddev->bitmap_offset = mddev->default_bitmap_offset;
4750 			mddev->pers->quiesce(mddev, 1);
4751 			rv = bitmap_create(mddev);
4752 			if (rv)
4753 				bitmap_destroy(mddev);
4754 			mddev->pers->quiesce(mddev, 0);
4755 		} else {
4756 			/* remove the bitmap */
4757 			if (!mddev->bitmap)
4758 				return -ENOENT;
4759 			if (mddev->bitmap->file)
4760 				return -EINVAL;
4761 			mddev->pers->quiesce(mddev, 1);
4762 			bitmap_destroy(mddev);
4763 			mddev->pers->quiesce(mddev, 0);
4764 			mddev->bitmap_offset = 0;
4765 		}
4766 	}
4767 	md_update_sb(mddev, 1);
4768 	return rv;
4769 }
4770 
4771 static int set_disk_faulty(mddev_t *mddev, dev_t dev)
4772 {
4773 	mdk_rdev_t *rdev;
4774 
4775 	if (mddev->pers == NULL)
4776 		return -ENODEV;
4777 
4778 	rdev = find_rdev(mddev, dev);
4779 	if (!rdev)
4780 		return -ENODEV;
4781 
4782 	md_error(mddev, rdev);
4783 	return 0;
4784 }
4785 
4786 /*
4787  * We have a problem here : there is no easy way to give a CHS
4788  * virtual geometry. We currently pretend that we have a 2 heads
4789  * 4 sectors (with a BIG number of cylinders...). This drives
4790  * dosfs just mad... ;-)
4791  */
4792 static int md_getgeo(struct block_device *bdev, struct hd_geometry *geo)
4793 {
4794 	mddev_t *mddev = bdev->bd_disk->private_data;
4795 
4796 	geo->heads = 2;
4797 	geo->sectors = 4;
4798 	geo->cylinders = get_capacity(mddev->gendisk) / 8;
4799 	return 0;
4800 }
4801 
4802 static int md_ioctl(struct block_device *bdev, fmode_t mode,
4803 			unsigned int cmd, unsigned long arg)
4804 {
4805 	int err = 0;
4806 	void __user *argp = (void __user *)arg;
4807 	mddev_t *mddev = NULL;
4808 
4809 	if (!capable(CAP_SYS_ADMIN))
4810 		return -EACCES;
4811 
4812 	/*
4813 	 * Commands dealing with the RAID driver but not any
4814 	 * particular array:
4815 	 */
4816 	switch (cmd)
4817 	{
4818 		case RAID_VERSION:
4819 			err = get_version(argp);
4820 			goto done;
4821 
4822 		case PRINT_RAID_DEBUG:
4823 			err = 0;
4824 			md_print_devices();
4825 			goto done;
4826 
4827 #ifndef MODULE
4828 		case RAID_AUTORUN:
4829 			err = 0;
4830 			autostart_arrays(arg);
4831 			goto done;
4832 #endif
4833 		default:;
4834 	}
4835 
4836 	/*
4837 	 * Commands creating/starting a new array:
4838 	 */
4839 
4840 	mddev = bdev->bd_disk->private_data;
4841 
4842 	if (!mddev) {
4843 		BUG();
4844 		goto abort;
4845 	}
4846 
4847 	err = mddev_lock(mddev);
4848 	if (err) {
4849 		printk(KERN_INFO
4850 			"md: ioctl lock interrupted, reason %d, cmd %d\n",
4851 			err, cmd);
4852 		goto abort;
4853 	}
4854 
4855 	switch (cmd)
4856 	{
4857 		case SET_ARRAY_INFO:
4858 			{
4859 				mdu_array_info_t info;
4860 				if (!arg)
4861 					memset(&info, 0, sizeof(info));
4862 				else if (copy_from_user(&info, argp, sizeof(info))) {
4863 					err = -EFAULT;
4864 					goto abort_unlock;
4865 				}
4866 				if (mddev->pers) {
4867 					err = update_array_info(mddev, &info);
4868 					if (err) {
4869 						printk(KERN_WARNING "md: couldn't update"
4870 						       " array info. %d\n", err);
4871 						goto abort_unlock;
4872 					}
4873 					goto done_unlock;
4874 				}
4875 				if (!list_empty(&mddev->disks)) {
4876 					printk(KERN_WARNING
4877 					       "md: array %s already has disks!\n",
4878 					       mdname(mddev));
4879 					err = -EBUSY;
4880 					goto abort_unlock;
4881 				}
4882 				if (mddev->raid_disks) {
4883 					printk(KERN_WARNING
4884 					       "md: array %s already initialised!\n",
4885 					       mdname(mddev));
4886 					err = -EBUSY;
4887 					goto abort_unlock;
4888 				}
4889 				err = set_array_info(mddev, &info);
4890 				if (err) {
4891 					printk(KERN_WARNING "md: couldn't set"
4892 					       " array info. %d\n", err);
4893 					goto abort_unlock;
4894 				}
4895 			}
4896 			goto done_unlock;
4897 
4898 		default:;
4899 	}
4900 
4901 	/*
4902 	 * Commands querying/configuring an existing array:
4903 	 */
4904 	/* if we are not initialised yet, only ADD_NEW_DISK, STOP_ARRAY,
4905 	 * RUN_ARRAY, and GET_ and SET_BITMAP_FILE are allowed */
4906 	if ((!mddev->raid_disks && !mddev->external)
4907 	    && cmd != ADD_NEW_DISK && cmd != STOP_ARRAY
4908 	    && cmd != RUN_ARRAY && cmd != SET_BITMAP_FILE
4909 	    && cmd != GET_BITMAP_FILE) {
4910 		err = -ENODEV;
4911 		goto abort_unlock;
4912 	}
4913 
4914 	/*
4915 	 * Commands even a read-only array can execute:
4916 	 */
4917 	switch (cmd)
4918 	{
4919 		case GET_ARRAY_INFO:
4920 			err = get_array_info(mddev, argp);
4921 			goto done_unlock;
4922 
4923 		case GET_BITMAP_FILE:
4924 			err = get_bitmap_file(mddev, argp);
4925 			goto done_unlock;
4926 
4927 		case GET_DISK_INFO:
4928 			err = get_disk_info(mddev, argp);
4929 			goto done_unlock;
4930 
4931 		case RESTART_ARRAY_RW:
4932 			err = restart_array(mddev);
4933 			goto done_unlock;
4934 
4935 		case STOP_ARRAY:
4936 			err = do_md_stop(mddev, 0, 1);
4937 			goto done_unlock;
4938 
4939 		case STOP_ARRAY_RO:
4940 			err = do_md_stop(mddev, 1, 1);
4941 			goto done_unlock;
4942 
4943 	}
4944 
4945 	/*
4946 	 * The remaining ioctls are changing the state of the
4947 	 * superblock, so we do not allow them on read-only arrays.
4948 	 * However non-MD ioctls (e.g. get-size) will still come through
4949 	 * here and hit the 'default' below, so only disallow
4950 	 * 'md' ioctls, and switch to rw mode if started auto-readonly.
4951 	 */
4952 	if (_IOC_TYPE(cmd) == MD_MAJOR && mddev->ro && mddev->pers) {
4953 		if (mddev->ro == 2) {
4954 			mddev->ro = 0;
4955 			sysfs_notify_dirent(mddev->sysfs_state);
4956 			set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
4957 			md_wakeup_thread(mddev->thread);
4958 		} else {
4959 			err = -EROFS;
4960 			goto abort_unlock;
4961 		}
4962 	}
4963 
4964 	switch (cmd)
4965 	{
4966 		case ADD_NEW_DISK:
4967 		{
4968 			mdu_disk_info_t info;
4969 			if (copy_from_user(&info, argp, sizeof(info)))
4970 				err = -EFAULT;
4971 			else
4972 				err = add_new_disk(mddev, &info);
4973 			goto done_unlock;
4974 		}
4975 
4976 		case HOT_REMOVE_DISK:
4977 			err = hot_remove_disk(mddev, new_decode_dev(arg));
4978 			goto done_unlock;
4979 
4980 		case HOT_ADD_DISK:
4981 			err = hot_add_disk(mddev, new_decode_dev(arg));
4982 			goto done_unlock;
4983 
4984 		case SET_DISK_FAULTY:
4985 			err = set_disk_faulty(mddev, new_decode_dev(arg));
4986 			goto done_unlock;
4987 
4988 		case RUN_ARRAY:
4989 			err = do_md_run(mddev);
4990 			goto done_unlock;
4991 
4992 		case SET_BITMAP_FILE:
4993 			err = set_bitmap_file(mddev, (int)arg);
4994 			goto done_unlock;
4995 
4996 		default:
4997 			err = -EINVAL;
4998 			goto abort_unlock;
4999 	}
5000 
5001 done_unlock:
5002 abort_unlock:
5003 	mddev_unlock(mddev);
5004 
5005 	return err;
5006 done:
5007 	if (err)
5008 		MD_BUG();
5009 abort:
5010 	return err;
5011 }
5012 
5013 static int md_open(struct block_device *bdev, fmode_t mode)
5014 {
5015 	/*
5016 	 * Succeed if we can lock the mddev, which confirms that
5017 	 * it isn't being stopped right now.
5018 	 */
5019 	mddev_t *mddev = bdev->bd_disk->private_data;
5020 	int err;
5021 
5022 	if ((err = mutex_lock_interruptible_nested(&mddev->reconfig_mutex, 1)))
5023 		goto out;
5024 
5025 	err = 0;
5026 	mddev_get(mddev);
5027 	atomic_inc(&mddev->openers);
5028 	mddev_unlock(mddev);
5029 
5030 	check_disk_change(bdev);
5031  out:
5032 	return err;
5033 }
5034 
5035 static int md_release(struct gendisk *disk, fmode_t mode)
5036 {
5037  	mddev_t *mddev = disk->private_data;
5038 
5039 	BUG_ON(!mddev);
5040 	atomic_dec(&mddev->openers);
5041 	mddev_put(mddev);
5042 
5043 	return 0;
5044 }
5045 
5046 static int md_media_changed(struct gendisk *disk)
5047 {
5048 	mddev_t *mddev = disk->private_data;
5049 
5050 	return mddev->changed;
5051 }
5052 
5053 static int md_revalidate(struct gendisk *disk)
5054 {
5055 	mddev_t *mddev = disk->private_data;
5056 
5057 	mddev->changed = 0;
5058 	return 0;
5059 }
5060 static struct block_device_operations md_fops =
5061 {
5062 	.owner		= THIS_MODULE,
5063 	.open		= md_open,
5064 	.release	= md_release,
5065 	.locked_ioctl	= md_ioctl,
5066 	.getgeo		= md_getgeo,
5067 	.media_changed	= md_media_changed,
5068 	.revalidate_disk= md_revalidate,
5069 };
5070 
5071 static int md_thread(void * arg)
5072 {
5073 	mdk_thread_t *thread = arg;
5074 
5075 	/*
5076 	 * md_thread is a 'system-thread', it's priority should be very
5077 	 * high. We avoid resource deadlocks individually in each
5078 	 * raid personality. (RAID5 does preallocation) We also use RR and
5079 	 * the very same RT priority as kswapd, thus we will never get
5080 	 * into a priority inversion deadlock.
5081 	 *
5082 	 * we definitely have to have equal or higher priority than
5083 	 * bdflush, otherwise bdflush will deadlock if there are too
5084 	 * many dirty RAID5 blocks.
5085 	 */
5086 
5087 	allow_signal(SIGKILL);
5088 	while (!kthread_should_stop()) {
5089 
5090 		/* We need to wait INTERRUPTIBLE so that
5091 		 * we don't add to the load-average.
5092 		 * That means we need to be sure no signals are
5093 		 * pending
5094 		 */
5095 		if (signal_pending(current))
5096 			flush_signals(current);
5097 
5098 		wait_event_interruptible_timeout
5099 			(thread->wqueue,
5100 			 test_bit(THREAD_WAKEUP, &thread->flags)
5101 			 || kthread_should_stop(),
5102 			 thread->timeout);
5103 
5104 		clear_bit(THREAD_WAKEUP, &thread->flags);
5105 
5106 		thread->run(thread->mddev);
5107 	}
5108 
5109 	return 0;
5110 }
5111 
5112 void md_wakeup_thread(mdk_thread_t *thread)
5113 {
5114 	if (thread) {
5115 		dprintk("md: waking up MD thread %s.\n", thread->tsk->comm);
5116 		set_bit(THREAD_WAKEUP, &thread->flags);
5117 		wake_up(&thread->wqueue);
5118 	}
5119 }
5120 
5121 mdk_thread_t *md_register_thread(void (*run) (mddev_t *), mddev_t *mddev,
5122 				 const char *name)
5123 {
5124 	mdk_thread_t *thread;
5125 
5126 	thread = kzalloc(sizeof(mdk_thread_t), GFP_KERNEL);
5127 	if (!thread)
5128 		return NULL;
5129 
5130 	init_waitqueue_head(&thread->wqueue);
5131 
5132 	thread->run = run;
5133 	thread->mddev = mddev;
5134 	thread->timeout = MAX_SCHEDULE_TIMEOUT;
5135 	thread->tsk = kthread_run(md_thread, thread, name, mdname(thread->mddev));
5136 	if (IS_ERR(thread->tsk)) {
5137 		kfree(thread);
5138 		return NULL;
5139 	}
5140 	return thread;
5141 }
5142 
5143 void md_unregister_thread(mdk_thread_t *thread)
5144 {
5145 	dprintk("interrupting MD-thread pid %d\n", task_pid_nr(thread->tsk));
5146 
5147 	kthread_stop(thread->tsk);
5148 	kfree(thread);
5149 }
5150 
5151 void md_error(mddev_t *mddev, mdk_rdev_t *rdev)
5152 {
5153 	if (!mddev) {
5154 		MD_BUG();
5155 		return;
5156 	}
5157 
5158 	if (!rdev || test_bit(Faulty, &rdev->flags))
5159 		return;
5160 
5161 	if (mddev->external)
5162 		set_bit(Blocked, &rdev->flags);
5163 /*
5164 	dprintk("md_error dev:%s, rdev:(%d:%d), (caller: %p,%p,%p,%p).\n",
5165 		mdname(mddev),
5166 		MAJOR(rdev->bdev->bd_dev), MINOR(rdev->bdev->bd_dev),
5167 		__builtin_return_address(0),__builtin_return_address(1),
5168 		__builtin_return_address(2),__builtin_return_address(3));
5169 */
5170 	if (!mddev->pers)
5171 		return;
5172 	if (!mddev->pers->error_handler)
5173 		return;
5174 	mddev->pers->error_handler(mddev,rdev);
5175 	if (mddev->degraded)
5176 		set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
5177 	set_bit(StateChanged, &rdev->flags);
5178 	set_bit(MD_RECOVERY_INTR, &mddev->recovery);
5179 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
5180 	md_wakeup_thread(mddev->thread);
5181 	md_new_event_inintr(mddev);
5182 }
5183 
5184 /* seq_file implementation /proc/mdstat */
5185 
5186 static void status_unused(struct seq_file *seq)
5187 {
5188 	int i = 0;
5189 	mdk_rdev_t *rdev;
5190 	struct list_head *tmp;
5191 
5192 	seq_printf(seq, "unused devices: ");
5193 
5194 	rdev_for_each_list(rdev, tmp, pending_raid_disks) {
5195 		char b[BDEVNAME_SIZE];
5196 		i++;
5197 		seq_printf(seq, "%s ",
5198 			      bdevname(rdev->bdev,b));
5199 	}
5200 	if (!i)
5201 		seq_printf(seq, "<none>");
5202 
5203 	seq_printf(seq, "\n");
5204 }
5205 
5206 
5207 static void status_resync(struct seq_file *seq, mddev_t * mddev)
5208 {
5209 	sector_t max_blocks, resync, res;
5210 	unsigned long dt, db, rt;
5211 	int scale;
5212 	unsigned int per_milli;
5213 
5214 	resync = (mddev->curr_resync - atomic_read(&mddev->recovery_active))/2;
5215 
5216 	if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery))
5217 		max_blocks = mddev->resync_max_sectors >> 1;
5218 	else
5219 		max_blocks = mddev->size;
5220 
5221 	/*
5222 	 * Should not happen.
5223 	 */
5224 	if (!max_blocks) {
5225 		MD_BUG();
5226 		return;
5227 	}
5228 	/* Pick 'scale' such that (resync>>scale)*1000 will fit
5229 	 * in a sector_t, and (max_blocks>>scale) will fit in a
5230 	 * u32, as those are the requirements for sector_div.
5231 	 * Thus 'scale' must be at least 10
5232 	 */
5233 	scale = 10;
5234 	if (sizeof(sector_t) > sizeof(unsigned long)) {
5235 		while ( max_blocks/2 > (1ULL<<(scale+32)))
5236 			scale++;
5237 	}
5238 	res = (resync>>scale)*1000;
5239 	sector_div(res, (u32)((max_blocks>>scale)+1));
5240 
5241 	per_milli = res;
5242 	{
5243 		int i, x = per_milli/50, y = 20-x;
5244 		seq_printf(seq, "[");
5245 		for (i = 0; i < x; i++)
5246 			seq_printf(seq, "=");
5247 		seq_printf(seq, ">");
5248 		for (i = 0; i < y; i++)
5249 			seq_printf(seq, ".");
5250 		seq_printf(seq, "] ");
5251 	}
5252 	seq_printf(seq, " %s =%3u.%u%% (%llu/%llu)",
5253 		   (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)?
5254 		    "reshape" :
5255 		    (test_bit(MD_RECOVERY_CHECK, &mddev->recovery)?
5256 		     "check" :
5257 		     (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) ?
5258 		      "resync" : "recovery"))),
5259 		   per_milli/10, per_milli % 10,
5260 		   (unsigned long long) resync,
5261 		   (unsigned long long) max_blocks);
5262 
5263 	/*
5264 	 * We do not want to overflow, so the order of operands and
5265 	 * the * 100 / 100 trick are important. We do a +1 to be
5266 	 * safe against division by zero. We only estimate anyway.
5267 	 *
5268 	 * dt: time from mark until now
5269 	 * db: blocks written from mark until now
5270 	 * rt: remaining time
5271 	 */
5272 	dt = ((jiffies - mddev->resync_mark) / HZ);
5273 	if (!dt) dt++;
5274 	db = (mddev->curr_mark_cnt - atomic_read(&mddev->recovery_active))
5275 		- mddev->resync_mark_cnt;
5276 	rt = (dt * ((unsigned long)(max_blocks-resync) / (db/2/100+1)))/100;
5277 
5278 	seq_printf(seq, " finish=%lu.%lumin", rt / 60, (rt % 60)/6);
5279 
5280 	seq_printf(seq, " speed=%ldK/sec", db/2/dt);
5281 }
5282 
5283 static void *md_seq_start(struct seq_file *seq, loff_t *pos)
5284 {
5285 	struct list_head *tmp;
5286 	loff_t l = *pos;
5287 	mddev_t *mddev;
5288 
5289 	if (l >= 0x10000)
5290 		return NULL;
5291 	if (!l--)
5292 		/* header */
5293 		return (void*)1;
5294 
5295 	spin_lock(&all_mddevs_lock);
5296 	list_for_each(tmp,&all_mddevs)
5297 		if (!l--) {
5298 			mddev = list_entry(tmp, mddev_t, all_mddevs);
5299 			mddev_get(mddev);
5300 			spin_unlock(&all_mddevs_lock);
5301 			return mddev;
5302 		}
5303 	spin_unlock(&all_mddevs_lock);
5304 	if (!l--)
5305 		return (void*)2;/* tail */
5306 	return NULL;
5307 }
5308 
5309 static void *md_seq_next(struct seq_file *seq, void *v, loff_t *pos)
5310 {
5311 	struct list_head *tmp;
5312 	mddev_t *next_mddev, *mddev = v;
5313 
5314 	++*pos;
5315 	if (v == (void*)2)
5316 		return NULL;
5317 
5318 	spin_lock(&all_mddevs_lock);
5319 	if (v == (void*)1)
5320 		tmp = all_mddevs.next;
5321 	else
5322 		tmp = mddev->all_mddevs.next;
5323 	if (tmp != &all_mddevs)
5324 		next_mddev = mddev_get(list_entry(tmp,mddev_t,all_mddevs));
5325 	else {
5326 		next_mddev = (void*)2;
5327 		*pos = 0x10000;
5328 	}
5329 	spin_unlock(&all_mddevs_lock);
5330 
5331 	if (v != (void*)1)
5332 		mddev_put(mddev);
5333 	return next_mddev;
5334 
5335 }
5336 
5337 static void md_seq_stop(struct seq_file *seq, void *v)
5338 {
5339 	mddev_t *mddev = v;
5340 
5341 	if (mddev && v != (void*)1 && v != (void*)2)
5342 		mddev_put(mddev);
5343 }
5344 
5345 struct mdstat_info {
5346 	int event;
5347 };
5348 
5349 static int md_seq_show(struct seq_file *seq, void *v)
5350 {
5351 	mddev_t *mddev = v;
5352 	sector_t size;
5353 	struct list_head *tmp2;
5354 	mdk_rdev_t *rdev;
5355 	struct mdstat_info *mi = seq->private;
5356 	struct bitmap *bitmap;
5357 
5358 	if (v == (void*)1) {
5359 		struct mdk_personality *pers;
5360 		seq_printf(seq, "Personalities : ");
5361 		spin_lock(&pers_lock);
5362 		list_for_each_entry(pers, &pers_list, list)
5363 			seq_printf(seq, "[%s] ", pers->name);
5364 
5365 		spin_unlock(&pers_lock);
5366 		seq_printf(seq, "\n");
5367 		mi->event = atomic_read(&md_event_count);
5368 		return 0;
5369 	}
5370 	if (v == (void*)2) {
5371 		status_unused(seq);
5372 		return 0;
5373 	}
5374 
5375 	if (mddev_lock(mddev) < 0)
5376 		return -EINTR;
5377 
5378 	if (mddev->pers || mddev->raid_disks || !list_empty(&mddev->disks)) {
5379 		seq_printf(seq, "%s : %sactive", mdname(mddev),
5380 						mddev->pers ? "" : "in");
5381 		if (mddev->pers) {
5382 			if (mddev->ro==1)
5383 				seq_printf(seq, " (read-only)");
5384 			if (mddev->ro==2)
5385 				seq_printf(seq, " (auto-read-only)");
5386 			seq_printf(seq, " %s", mddev->pers->name);
5387 		}
5388 
5389 		size = 0;
5390 		rdev_for_each(rdev, tmp2, mddev) {
5391 			char b[BDEVNAME_SIZE];
5392 			seq_printf(seq, " %s[%d]",
5393 				bdevname(rdev->bdev,b), rdev->desc_nr);
5394 			if (test_bit(WriteMostly, &rdev->flags))
5395 				seq_printf(seq, "(W)");
5396 			if (test_bit(Faulty, &rdev->flags)) {
5397 				seq_printf(seq, "(F)");
5398 				continue;
5399 			} else if (rdev->raid_disk < 0)
5400 				seq_printf(seq, "(S)"); /* spare */
5401 			size += rdev->size;
5402 		}
5403 
5404 		if (!list_empty(&mddev->disks)) {
5405 			if (mddev->pers)
5406 				seq_printf(seq, "\n      %llu blocks",
5407 					   (unsigned long long)
5408 					   mddev->array_sectors / 2);
5409 			else
5410 				seq_printf(seq, "\n      %llu blocks",
5411 					   (unsigned long long)size);
5412 		}
5413 		if (mddev->persistent) {
5414 			if (mddev->major_version != 0 ||
5415 			    mddev->minor_version != 90) {
5416 				seq_printf(seq," super %d.%d",
5417 					   mddev->major_version,
5418 					   mddev->minor_version);
5419 			}
5420 		} else if (mddev->external)
5421 			seq_printf(seq, " super external:%s",
5422 				   mddev->metadata_type);
5423 		else
5424 			seq_printf(seq, " super non-persistent");
5425 
5426 		if (mddev->pers) {
5427 			mddev->pers->status(seq, mddev);
5428 	 		seq_printf(seq, "\n      ");
5429 			if (mddev->pers->sync_request) {
5430 				if (mddev->curr_resync > 2) {
5431 					status_resync(seq, mddev);
5432 					seq_printf(seq, "\n      ");
5433 				} else if (mddev->curr_resync == 1 || mddev->curr_resync == 2)
5434 					seq_printf(seq, "\tresync=DELAYED\n      ");
5435 				else if (mddev->recovery_cp < MaxSector)
5436 					seq_printf(seq, "\tresync=PENDING\n      ");
5437 			}
5438 		} else
5439 			seq_printf(seq, "\n       ");
5440 
5441 		if ((bitmap = mddev->bitmap)) {
5442 			unsigned long chunk_kb;
5443 			unsigned long flags;
5444 			spin_lock_irqsave(&bitmap->lock, flags);
5445 			chunk_kb = bitmap->chunksize >> 10;
5446 			seq_printf(seq, "bitmap: %lu/%lu pages [%luKB], "
5447 				"%lu%s chunk",
5448 				bitmap->pages - bitmap->missing_pages,
5449 				bitmap->pages,
5450 				(bitmap->pages - bitmap->missing_pages)
5451 					<< (PAGE_SHIFT - 10),
5452 				chunk_kb ? chunk_kb : bitmap->chunksize,
5453 				chunk_kb ? "KB" : "B");
5454 			if (bitmap->file) {
5455 				seq_printf(seq, ", file: ");
5456 				seq_path(seq, &bitmap->file->f_path, " \t\n");
5457 			}
5458 
5459 			seq_printf(seq, "\n");
5460 			spin_unlock_irqrestore(&bitmap->lock, flags);
5461 		}
5462 
5463 		seq_printf(seq, "\n");
5464 	}
5465 	mddev_unlock(mddev);
5466 
5467 	return 0;
5468 }
5469 
5470 static struct seq_operations md_seq_ops = {
5471 	.start  = md_seq_start,
5472 	.next   = md_seq_next,
5473 	.stop   = md_seq_stop,
5474 	.show   = md_seq_show,
5475 };
5476 
5477 static int md_seq_open(struct inode *inode, struct file *file)
5478 {
5479 	int error;
5480 	struct mdstat_info *mi = kmalloc(sizeof(*mi), GFP_KERNEL);
5481 	if (mi == NULL)
5482 		return -ENOMEM;
5483 
5484 	error = seq_open(file, &md_seq_ops);
5485 	if (error)
5486 		kfree(mi);
5487 	else {
5488 		struct seq_file *p = file->private_data;
5489 		p->private = mi;
5490 		mi->event = atomic_read(&md_event_count);
5491 	}
5492 	return error;
5493 }
5494 
5495 static unsigned int mdstat_poll(struct file *filp, poll_table *wait)
5496 {
5497 	struct seq_file *m = filp->private_data;
5498 	struct mdstat_info *mi = m->private;
5499 	int mask;
5500 
5501 	poll_wait(filp, &md_event_waiters, wait);
5502 
5503 	/* always allow read */
5504 	mask = POLLIN | POLLRDNORM;
5505 
5506 	if (mi->event != atomic_read(&md_event_count))
5507 		mask |= POLLERR | POLLPRI;
5508 	return mask;
5509 }
5510 
5511 static const struct file_operations md_seq_fops = {
5512 	.owner		= THIS_MODULE,
5513 	.open           = md_seq_open,
5514 	.read           = seq_read,
5515 	.llseek         = seq_lseek,
5516 	.release	= seq_release_private,
5517 	.poll		= mdstat_poll,
5518 };
5519 
5520 int register_md_personality(struct mdk_personality *p)
5521 {
5522 	spin_lock(&pers_lock);
5523 	list_add_tail(&p->list, &pers_list);
5524 	printk(KERN_INFO "md: %s personality registered for level %d\n", p->name, p->level);
5525 	spin_unlock(&pers_lock);
5526 	return 0;
5527 }
5528 
5529 int unregister_md_personality(struct mdk_personality *p)
5530 {
5531 	printk(KERN_INFO "md: %s personality unregistered\n", p->name);
5532 	spin_lock(&pers_lock);
5533 	list_del_init(&p->list);
5534 	spin_unlock(&pers_lock);
5535 	return 0;
5536 }
5537 
5538 static int is_mddev_idle(mddev_t *mddev)
5539 {
5540 	mdk_rdev_t * rdev;
5541 	int idle;
5542 	long curr_events;
5543 
5544 	idle = 1;
5545 	rcu_read_lock();
5546 	rdev_for_each_rcu(rdev, mddev) {
5547 		struct gendisk *disk = rdev->bdev->bd_contains->bd_disk;
5548 		curr_events = part_stat_read(&disk->part0, sectors[0]) +
5549 				part_stat_read(&disk->part0, sectors[1]) -
5550 				atomic_read(&disk->sync_io);
5551 		/* sync IO will cause sync_io to increase before the disk_stats
5552 		 * as sync_io is counted when a request starts, and
5553 		 * disk_stats is counted when it completes.
5554 		 * So resync activity will cause curr_events to be smaller than
5555 		 * when there was no such activity.
5556 		 * non-sync IO will cause disk_stat to increase without
5557 		 * increasing sync_io so curr_events will (eventually)
5558 		 * be larger than it was before.  Once it becomes
5559 		 * substantially larger, the test below will cause
5560 		 * the array to appear non-idle, and resync will slow
5561 		 * down.
5562 		 * If there is a lot of outstanding resync activity when
5563 		 * we set last_event to curr_events, then all that activity
5564 		 * completing might cause the array to appear non-idle
5565 		 * and resync will be slowed down even though there might
5566 		 * not have been non-resync activity.  This will only
5567 		 * happen once though.  'last_events' will soon reflect
5568 		 * the state where there is little or no outstanding
5569 		 * resync requests, and further resync activity will
5570 		 * always make curr_events less than last_events.
5571 		 *
5572 		 */
5573 		if (curr_events - rdev->last_events > 4096) {
5574 			rdev->last_events = curr_events;
5575 			idle = 0;
5576 		}
5577 	}
5578 	rcu_read_unlock();
5579 	return idle;
5580 }
5581 
5582 void md_done_sync(mddev_t *mddev, int blocks, int ok)
5583 {
5584 	/* another "blocks" (512byte) blocks have been synced */
5585 	atomic_sub(blocks, &mddev->recovery_active);
5586 	wake_up(&mddev->recovery_wait);
5587 	if (!ok) {
5588 		set_bit(MD_RECOVERY_INTR, &mddev->recovery);
5589 		md_wakeup_thread(mddev->thread);
5590 		// stop recovery, signal do_sync ....
5591 	}
5592 }
5593 
5594 
5595 /* md_write_start(mddev, bi)
5596  * If we need to update some array metadata (e.g. 'active' flag
5597  * in superblock) before writing, schedule a superblock update
5598  * and wait for it to complete.
5599  */
5600 void md_write_start(mddev_t *mddev, struct bio *bi)
5601 {
5602 	int did_change = 0;
5603 	if (bio_data_dir(bi) != WRITE)
5604 		return;
5605 
5606 	BUG_ON(mddev->ro == 1);
5607 	if (mddev->ro == 2) {
5608 		/* need to switch to read/write */
5609 		mddev->ro = 0;
5610 		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
5611 		md_wakeup_thread(mddev->thread);
5612 		md_wakeup_thread(mddev->sync_thread);
5613 		did_change = 1;
5614 	}
5615 	atomic_inc(&mddev->writes_pending);
5616 	if (mddev->safemode == 1)
5617 		mddev->safemode = 0;
5618 	if (mddev->in_sync) {
5619 		spin_lock_irq(&mddev->write_lock);
5620 		if (mddev->in_sync) {
5621 			mddev->in_sync = 0;
5622 			set_bit(MD_CHANGE_CLEAN, &mddev->flags);
5623 			md_wakeup_thread(mddev->thread);
5624 			did_change = 1;
5625 		}
5626 		spin_unlock_irq(&mddev->write_lock);
5627 	}
5628 	if (did_change)
5629 		sysfs_notify_dirent(mddev->sysfs_state);
5630 	wait_event(mddev->sb_wait,
5631 		   !test_bit(MD_CHANGE_CLEAN, &mddev->flags) &&
5632 		   !test_bit(MD_CHANGE_PENDING, &mddev->flags));
5633 }
5634 
5635 void md_write_end(mddev_t *mddev)
5636 {
5637 	if (atomic_dec_and_test(&mddev->writes_pending)) {
5638 		if (mddev->safemode == 2)
5639 			md_wakeup_thread(mddev->thread);
5640 		else if (mddev->safemode_delay)
5641 			mod_timer(&mddev->safemode_timer, jiffies + mddev->safemode_delay);
5642 	}
5643 }
5644 
5645 /* md_allow_write(mddev)
5646  * Calling this ensures that the array is marked 'active' so that writes
5647  * may proceed without blocking.  It is important to call this before
5648  * attempting a GFP_KERNEL allocation while holding the mddev lock.
5649  * Must be called with mddev_lock held.
5650  *
5651  * In the ->external case MD_CHANGE_CLEAN can not be cleared until mddev->lock
5652  * is dropped, so return -EAGAIN after notifying userspace.
5653  */
5654 int md_allow_write(mddev_t *mddev)
5655 {
5656 	if (!mddev->pers)
5657 		return 0;
5658 	if (mddev->ro)
5659 		return 0;
5660 	if (!mddev->pers->sync_request)
5661 		return 0;
5662 
5663 	spin_lock_irq(&mddev->write_lock);
5664 	if (mddev->in_sync) {
5665 		mddev->in_sync = 0;
5666 		set_bit(MD_CHANGE_CLEAN, &mddev->flags);
5667 		if (mddev->safemode_delay &&
5668 		    mddev->safemode == 0)
5669 			mddev->safemode = 1;
5670 		spin_unlock_irq(&mddev->write_lock);
5671 		md_update_sb(mddev, 0);
5672 		sysfs_notify_dirent(mddev->sysfs_state);
5673 	} else
5674 		spin_unlock_irq(&mddev->write_lock);
5675 
5676 	if (test_bit(MD_CHANGE_CLEAN, &mddev->flags))
5677 		return -EAGAIN;
5678 	else
5679 		return 0;
5680 }
5681 EXPORT_SYMBOL_GPL(md_allow_write);
5682 
5683 #define SYNC_MARKS	10
5684 #define	SYNC_MARK_STEP	(3*HZ)
5685 void md_do_sync(mddev_t *mddev)
5686 {
5687 	mddev_t *mddev2;
5688 	unsigned int currspeed = 0,
5689 		 window;
5690 	sector_t max_sectors,j, io_sectors;
5691 	unsigned long mark[SYNC_MARKS];
5692 	sector_t mark_cnt[SYNC_MARKS];
5693 	int last_mark,m;
5694 	struct list_head *tmp;
5695 	sector_t last_check;
5696 	int skipped = 0;
5697 	struct list_head *rtmp;
5698 	mdk_rdev_t *rdev;
5699 	char *desc;
5700 
5701 	/* just incase thread restarts... */
5702 	if (test_bit(MD_RECOVERY_DONE, &mddev->recovery))
5703 		return;
5704 	if (mddev->ro) /* never try to sync a read-only array */
5705 		return;
5706 
5707 	if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
5708 		if (test_bit(MD_RECOVERY_CHECK, &mddev->recovery))
5709 			desc = "data-check";
5710 		else if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
5711 			desc = "requested-resync";
5712 		else
5713 			desc = "resync";
5714 	} else if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
5715 		desc = "reshape";
5716 	else
5717 		desc = "recovery";
5718 
5719 	/* we overload curr_resync somewhat here.
5720 	 * 0 == not engaged in resync at all
5721 	 * 2 == checking that there is no conflict with another sync
5722 	 * 1 == like 2, but have yielded to allow conflicting resync to
5723 	 *		commense
5724 	 * other == active in resync - this many blocks
5725 	 *
5726 	 * Before starting a resync we must have set curr_resync to
5727 	 * 2, and then checked that every "conflicting" array has curr_resync
5728 	 * less than ours.  When we find one that is the same or higher
5729 	 * we wait on resync_wait.  To avoid deadlock, we reduce curr_resync
5730 	 * to 1 if we choose to yield (based arbitrarily on address of mddev structure).
5731 	 * This will mean we have to start checking from the beginning again.
5732 	 *
5733 	 */
5734 
5735 	do {
5736 		mddev->curr_resync = 2;
5737 
5738 	try_again:
5739 		if (kthread_should_stop()) {
5740 			set_bit(MD_RECOVERY_INTR, &mddev->recovery);
5741 			goto skip;
5742 		}
5743 		for_each_mddev(mddev2, tmp) {
5744 			if (mddev2 == mddev)
5745 				continue;
5746 			if (!mddev->parallel_resync
5747 			&&  mddev2->curr_resync
5748 			&&  match_mddev_units(mddev, mddev2)) {
5749 				DEFINE_WAIT(wq);
5750 				if (mddev < mddev2 && mddev->curr_resync == 2) {
5751 					/* arbitrarily yield */
5752 					mddev->curr_resync = 1;
5753 					wake_up(&resync_wait);
5754 				}
5755 				if (mddev > mddev2 && mddev->curr_resync == 1)
5756 					/* no need to wait here, we can wait the next
5757 					 * time 'round when curr_resync == 2
5758 					 */
5759 					continue;
5760 				/* We need to wait 'interruptible' so as not to
5761 				 * contribute to the load average, and not to
5762 				 * be caught by 'softlockup'
5763 				 */
5764 				prepare_to_wait(&resync_wait, &wq, TASK_INTERRUPTIBLE);
5765 				if (!kthread_should_stop() &&
5766 				    mddev2->curr_resync >= mddev->curr_resync) {
5767 					printk(KERN_INFO "md: delaying %s of %s"
5768 					       " until %s has finished (they"
5769 					       " share one or more physical units)\n",
5770 					       desc, mdname(mddev), mdname(mddev2));
5771 					mddev_put(mddev2);
5772 					if (signal_pending(current))
5773 						flush_signals(current);
5774 					schedule();
5775 					finish_wait(&resync_wait, &wq);
5776 					goto try_again;
5777 				}
5778 				finish_wait(&resync_wait, &wq);
5779 			}
5780 		}
5781 	} while (mddev->curr_resync < 2);
5782 
5783 	j = 0;
5784 	if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
5785 		/* resync follows the size requested by the personality,
5786 		 * which defaults to physical size, but can be virtual size
5787 		 */
5788 		max_sectors = mddev->resync_max_sectors;
5789 		mddev->resync_mismatches = 0;
5790 		/* we don't use the checkpoint if there's a bitmap */
5791 		if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
5792 			j = mddev->resync_min;
5793 		else if (!mddev->bitmap)
5794 			j = mddev->recovery_cp;
5795 
5796 	} else if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
5797 		max_sectors = mddev->size << 1;
5798 	else {
5799 		/* recovery follows the physical size of devices */
5800 		max_sectors = mddev->size << 1;
5801 		j = MaxSector;
5802 		rdev_for_each(rdev, rtmp, mddev)
5803 			if (rdev->raid_disk >= 0 &&
5804 			    !test_bit(Faulty, &rdev->flags) &&
5805 			    !test_bit(In_sync, &rdev->flags) &&
5806 			    rdev->recovery_offset < j)
5807 				j = rdev->recovery_offset;
5808 	}
5809 
5810 	printk(KERN_INFO "md: %s of RAID array %s\n", desc, mdname(mddev));
5811 	printk(KERN_INFO "md: minimum _guaranteed_  speed:"
5812 		" %d KB/sec/disk.\n", speed_min(mddev));
5813 	printk(KERN_INFO "md: using maximum available idle IO bandwidth "
5814 	       "(but not more than %d KB/sec) for %s.\n",
5815 	       speed_max(mddev), desc);
5816 
5817 	is_mddev_idle(mddev); /* this also initializes IO event counters */
5818 
5819 	io_sectors = 0;
5820 	for (m = 0; m < SYNC_MARKS; m++) {
5821 		mark[m] = jiffies;
5822 		mark_cnt[m] = io_sectors;
5823 	}
5824 	last_mark = 0;
5825 	mddev->resync_mark = mark[last_mark];
5826 	mddev->resync_mark_cnt = mark_cnt[last_mark];
5827 
5828 	/*
5829 	 * Tune reconstruction:
5830 	 */
5831 	window = 32*(PAGE_SIZE/512);
5832 	printk(KERN_INFO "md: using %dk window, over a total of %llu blocks.\n",
5833 		window/2,(unsigned long long) max_sectors/2);
5834 
5835 	atomic_set(&mddev->recovery_active, 0);
5836 	last_check = 0;
5837 
5838 	if (j>2) {
5839 		printk(KERN_INFO
5840 		       "md: resuming %s of %s from checkpoint.\n",
5841 		       desc, mdname(mddev));
5842 		mddev->curr_resync = j;
5843 	}
5844 
5845 	while (j < max_sectors) {
5846 		sector_t sectors;
5847 
5848 		skipped = 0;
5849 		if (j >= mddev->resync_max) {
5850 			sysfs_notify(&mddev->kobj, NULL, "sync_completed");
5851 			wait_event(mddev->recovery_wait,
5852 				   mddev->resync_max > j
5853 				   || kthread_should_stop());
5854 		}
5855 		if (kthread_should_stop())
5856 			goto interrupted;
5857 		sectors = mddev->pers->sync_request(mddev, j, &skipped,
5858 						  currspeed < speed_min(mddev));
5859 		if (sectors == 0) {
5860 			set_bit(MD_RECOVERY_INTR, &mddev->recovery);
5861 			goto out;
5862 		}
5863 
5864 		if (!skipped) { /* actual IO requested */
5865 			io_sectors += sectors;
5866 			atomic_add(sectors, &mddev->recovery_active);
5867 		}
5868 
5869 		j += sectors;
5870 		if (j>1) mddev->curr_resync = j;
5871 		mddev->curr_mark_cnt = io_sectors;
5872 		if (last_check == 0)
5873 			/* this is the earliers that rebuilt will be
5874 			 * visible in /proc/mdstat
5875 			 */
5876 			md_new_event(mddev);
5877 
5878 		if (last_check + window > io_sectors || j == max_sectors)
5879 			continue;
5880 
5881 		last_check = io_sectors;
5882 
5883 		if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
5884 			break;
5885 
5886 	repeat:
5887 		if (time_after_eq(jiffies, mark[last_mark] + SYNC_MARK_STEP )) {
5888 			/* step marks */
5889 			int next = (last_mark+1) % SYNC_MARKS;
5890 
5891 			mddev->resync_mark = mark[next];
5892 			mddev->resync_mark_cnt = mark_cnt[next];
5893 			mark[next] = jiffies;
5894 			mark_cnt[next] = io_sectors - atomic_read(&mddev->recovery_active);
5895 			last_mark = next;
5896 		}
5897 
5898 
5899 		if (kthread_should_stop())
5900 			goto interrupted;
5901 
5902 
5903 		/*
5904 		 * this loop exits only if either when we are slower than
5905 		 * the 'hard' speed limit, or the system was IO-idle for
5906 		 * a jiffy.
5907 		 * the system might be non-idle CPU-wise, but we only care
5908 		 * about not overloading the IO subsystem. (things like an
5909 		 * e2fsck being done on the RAID array should execute fast)
5910 		 */
5911 		blk_unplug(mddev->queue);
5912 		cond_resched();
5913 
5914 		currspeed = ((unsigned long)(io_sectors-mddev->resync_mark_cnt))/2
5915 			/((jiffies-mddev->resync_mark)/HZ +1) +1;
5916 
5917 		if (currspeed > speed_min(mddev)) {
5918 			if ((currspeed > speed_max(mddev)) ||
5919 					!is_mddev_idle(mddev)) {
5920 				msleep(500);
5921 				goto repeat;
5922 			}
5923 		}
5924 	}
5925 	printk(KERN_INFO "md: %s: %s done.\n",mdname(mddev), desc);
5926 	/*
5927 	 * this also signals 'finished resyncing' to md_stop
5928 	 */
5929  out:
5930 	blk_unplug(mddev->queue);
5931 
5932 	wait_event(mddev->recovery_wait, !atomic_read(&mddev->recovery_active));
5933 
5934 	/* tell personality that we are finished */
5935 	mddev->pers->sync_request(mddev, max_sectors, &skipped, 1);
5936 
5937 	if (!test_bit(MD_RECOVERY_CHECK, &mddev->recovery) &&
5938 	    mddev->curr_resync > 2) {
5939 		if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
5940 			if (test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
5941 				if (mddev->curr_resync >= mddev->recovery_cp) {
5942 					printk(KERN_INFO
5943 					       "md: checkpointing %s of %s.\n",
5944 					       desc, mdname(mddev));
5945 					mddev->recovery_cp = mddev->curr_resync;
5946 				}
5947 			} else
5948 				mddev->recovery_cp = MaxSector;
5949 		} else {
5950 			if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery))
5951 				mddev->curr_resync = MaxSector;
5952 			rdev_for_each(rdev, rtmp, mddev)
5953 				if (rdev->raid_disk >= 0 &&
5954 				    !test_bit(Faulty, &rdev->flags) &&
5955 				    !test_bit(In_sync, &rdev->flags) &&
5956 				    rdev->recovery_offset < mddev->curr_resync)
5957 					rdev->recovery_offset = mddev->curr_resync;
5958 		}
5959 	}
5960 	set_bit(MD_CHANGE_DEVS, &mddev->flags);
5961 
5962  skip:
5963 	mddev->curr_resync = 0;
5964 	mddev->resync_min = 0;
5965 	mddev->resync_max = MaxSector;
5966 	sysfs_notify(&mddev->kobj, NULL, "sync_completed");
5967 	wake_up(&resync_wait);
5968 	set_bit(MD_RECOVERY_DONE, &mddev->recovery);
5969 	md_wakeup_thread(mddev->thread);
5970 	return;
5971 
5972  interrupted:
5973 	/*
5974 	 * got a signal, exit.
5975 	 */
5976 	printk(KERN_INFO
5977 	       "md: md_do_sync() got signal ... exiting\n");
5978 	set_bit(MD_RECOVERY_INTR, &mddev->recovery);
5979 	goto out;
5980 
5981 }
5982 EXPORT_SYMBOL_GPL(md_do_sync);
5983 
5984 
5985 static int remove_and_add_spares(mddev_t *mddev)
5986 {
5987 	mdk_rdev_t *rdev;
5988 	struct list_head *rtmp;
5989 	int spares = 0;
5990 
5991 	rdev_for_each(rdev, rtmp, mddev)
5992 		if (rdev->raid_disk >= 0 &&
5993 		    !test_bit(Blocked, &rdev->flags) &&
5994 		    (test_bit(Faulty, &rdev->flags) ||
5995 		     ! test_bit(In_sync, &rdev->flags)) &&
5996 		    atomic_read(&rdev->nr_pending)==0) {
5997 			if (mddev->pers->hot_remove_disk(
5998 				    mddev, rdev->raid_disk)==0) {
5999 				char nm[20];
6000 				sprintf(nm,"rd%d", rdev->raid_disk);
6001 				sysfs_remove_link(&mddev->kobj, nm);
6002 				rdev->raid_disk = -1;
6003 			}
6004 		}
6005 
6006 	if (mddev->degraded && ! mddev->ro) {
6007 		rdev_for_each(rdev, rtmp, mddev) {
6008 			if (rdev->raid_disk >= 0 &&
6009 			    !test_bit(In_sync, &rdev->flags) &&
6010 			    !test_bit(Blocked, &rdev->flags))
6011 				spares++;
6012 			if (rdev->raid_disk < 0
6013 			    && !test_bit(Faulty, &rdev->flags)) {
6014 				rdev->recovery_offset = 0;
6015 				if (mddev->pers->
6016 				    hot_add_disk(mddev, rdev) == 0) {
6017 					char nm[20];
6018 					sprintf(nm, "rd%d", rdev->raid_disk);
6019 					if (sysfs_create_link(&mddev->kobj,
6020 							      &rdev->kobj, nm))
6021 						printk(KERN_WARNING
6022 						       "md: cannot register "
6023 						       "%s for %s\n",
6024 						       nm, mdname(mddev));
6025 					spares++;
6026 					md_new_event(mddev);
6027 				} else
6028 					break;
6029 			}
6030 		}
6031 	}
6032 	return spares;
6033 }
6034 /*
6035  * This routine is regularly called by all per-raid-array threads to
6036  * deal with generic issues like resync and super-block update.
6037  * Raid personalities that don't have a thread (linear/raid0) do not
6038  * need this as they never do any recovery or update the superblock.
6039  *
6040  * It does not do any resync itself, but rather "forks" off other threads
6041  * to do that as needed.
6042  * When it is determined that resync is needed, we set MD_RECOVERY_RUNNING in
6043  * "->recovery" and create a thread at ->sync_thread.
6044  * When the thread finishes it sets MD_RECOVERY_DONE
6045  * and wakeups up this thread which will reap the thread and finish up.
6046  * This thread also removes any faulty devices (with nr_pending == 0).
6047  *
6048  * The overall approach is:
6049  *  1/ if the superblock needs updating, update it.
6050  *  2/ If a recovery thread is running, don't do anything else.
6051  *  3/ If recovery has finished, clean up, possibly marking spares active.
6052  *  4/ If there are any faulty devices, remove them.
6053  *  5/ If array is degraded, try to add spares devices
6054  *  6/ If array has spares or is not in-sync, start a resync thread.
6055  */
6056 void md_check_recovery(mddev_t *mddev)
6057 {
6058 	mdk_rdev_t *rdev;
6059 	struct list_head *rtmp;
6060 
6061 
6062 	if (mddev->bitmap)
6063 		bitmap_daemon_work(mddev->bitmap);
6064 
6065 	if (mddev->ro)
6066 		return;
6067 
6068 	if (signal_pending(current)) {
6069 		if (mddev->pers->sync_request && !mddev->external) {
6070 			printk(KERN_INFO "md: %s in immediate safe mode\n",
6071 			       mdname(mddev));
6072 			mddev->safemode = 2;
6073 		}
6074 		flush_signals(current);
6075 	}
6076 
6077 	if (mddev->ro && !test_bit(MD_RECOVERY_NEEDED, &mddev->recovery))
6078 		return;
6079 	if ( ! (
6080 		(mddev->flags && !mddev->external) ||
6081 		test_bit(MD_RECOVERY_NEEDED, &mddev->recovery) ||
6082 		test_bit(MD_RECOVERY_DONE, &mddev->recovery) ||
6083 		(mddev->external == 0 && mddev->safemode == 1) ||
6084 		(mddev->safemode == 2 && ! atomic_read(&mddev->writes_pending)
6085 		 && !mddev->in_sync && mddev->recovery_cp == MaxSector)
6086 		))
6087 		return;
6088 
6089 	if (mddev_trylock(mddev)) {
6090 		int spares = 0;
6091 
6092 		if (mddev->ro) {
6093 			/* Only thing we do on a ro array is remove
6094 			 * failed devices.
6095 			 */
6096 			remove_and_add_spares(mddev);
6097 			clear_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
6098 			goto unlock;
6099 		}
6100 
6101 		if (!mddev->external) {
6102 			int did_change = 0;
6103 			spin_lock_irq(&mddev->write_lock);
6104 			if (mddev->safemode &&
6105 			    !atomic_read(&mddev->writes_pending) &&
6106 			    !mddev->in_sync &&
6107 			    mddev->recovery_cp == MaxSector) {
6108 				mddev->in_sync = 1;
6109 				did_change = 1;
6110 				if (mddev->persistent)
6111 					set_bit(MD_CHANGE_CLEAN, &mddev->flags);
6112 			}
6113 			if (mddev->safemode == 1)
6114 				mddev->safemode = 0;
6115 			spin_unlock_irq(&mddev->write_lock);
6116 			if (did_change)
6117 				sysfs_notify_dirent(mddev->sysfs_state);
6118 		}
6119 
6120 		if (mddev->flags)
6121 			md_update_sb(mddev, 0);
6122 
6123 		rdev_for_each(rdev, rtmp, mddev)
6124 			if (test_and_clear_bit(StateChanged, &rdev->flags))
6125 				sysfs_notify_dirent(rdev->sysfs_state);
6126 
6127 
6128 		if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) &&
6129 		    !test_bit(MD_RECOVERY_DONE, &mddev->recovery)) {
6130 			/* resync/recovery still happening */
6131 			clear_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
6132 			goto unlock;
6133 		}
6134 		if (mddev->sync_thread) {
6135 			/* resync has finished, collect result */
6136 			md_unregister_thread(mddev->sync_thread);
6137 			mddev->sync_thread = NULL;
6138 			if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery) &&
6139 			    !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
6140 				/* success...*/
6141 				/* activate any spares */
6142 				if (mddev->pers->spare_active(mddev))
6143 					sysfs_notify(&mddev->kobj, NULL,
6144 						     "degraded");
6145 			}
6146 			md_update_sb(mddev, 1);
6147 
6148 			/* if array is no-longer degraded, then any saved_raid_disk
6149 			 * information must be scrapped
6150 			 */
6151 			if (!mddev->degraded)
6152 				rdev_for_each(rdev, rtmp, mddev)
6153 					rdev->saved_raid_disk = -1;
6154 
6155 			mddev->recovery = 0;
6156 			/* flag recovery needed just to double check */
6157 			set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
6158 			sysfs_notify(&mddev->kobj, NULL, "sync_action");
6159 			md_new_event(mddev);
6160 			goto unlock;
6161 		}
6162 		/* Set RUNNING before clearing NEEDED to avoid
6163 		 * any transients in the value of "sync_action".
6164 		 */
6165 		set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
6166 		clear_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
6167 		/* Clear some bits that don't mean anything, but
6168 		 * might be left set
6169 		 */
6170 		clear_bit(MD_RECOVERY_INTR, &mddev->recovery);
6171 		clear_bit(MD_RECOVERY_DONE, &mddev->recovery);
6172 
6173 		if (test_bit(MD_RECOVERY_FROZEN, &mddev->recovery))
6174 			goto unlock;
6175 		/* no recovery is running.
6176 		 * remove any failed drives, then
6177 		 * add spares if possible.
6178 		 * Spare are also removed and re-added, to allow
6179 		 * the personality to fail the re-add.
6180 		 */
6181 
6182 		if (mddev->reshape_position != MaxSector) {
6183 			if (mddev->pers->check_reshape(mddev) != 0)
6184 				/* Cannot proceed */
6185 				goto unlock;
6186 			set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
6187 			clear_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
6188 		} else if ((spares = remove_and_add_spares(mddev))) {
6189 			clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
6190 			clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
6191 			clear_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
6192 			set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
6193 		} else if (mddev->recovery_cp < MaxSector) {
6194 			set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
6195 			clear_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
6196 		} else if (!test_bit(MD_RECOVERY_SYNC, &mddev->recovery))
6197 			/* nothing to be done ... */
6198 			goto unlock;
6199 
6200 		if (mddev->pers->sync_request) {
6201 			if (spares && mddev->bitmap && ! mddev->bitmap->file) {
6202 				/* We are adding a device or devices to an array
6203 				 * which has the bitmap stored on all devices.
6204 				 * So make sure all bitmap pages get written
6205 				 */
6206 				bitmap_write_all(mddev->bitmap);
6207 			}
6208 			mddev->sync_thread = md_register_thread(md_do_sync,
6209 								mddev,
6210 								"%s_resync");
6211 			if (!mddev->sync_thread) {
6212 				printk(KERN_ERR "%s: could not start resync"
6213 					" thread...\n",
6214 					mdname(mddev));
6215 				/* leave the spares where they are, it shouldn't hurt */
6216 				mddev->recovery = 0;
6217 			} else
6218 				md_wakeup_thread(mddev->sync_thread);
6219 			sysfs_notify(&mddev->kobj, NULL, "sync_action");
6220 			md_new_event(mddev);
6221 		}
6222 	unlock:
6223 		if (!mddev->sync_thread) {
6224 			clear_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
6225 			if (test_and_clear_bit(MD_RECOVERY_RECOVER,
6226 					       &mddev->recovery))
6227 				sysfs_notify(&mddev->kobj, NULL, "sync_action");
6228 		}
6229 		mddev_unlock(mddev);
6230 	}
6231 }
6232 
6233 void md_wait_for_blocked_rdev(mdk_rdev_t *rdev, mddev_t *mddev)
6234 {
6235 	sysfs_notify_dirent(rdev->sysfs_state);
6236 	wait_event_timeout(rdev->blocked_wait,
6237 			   !test_bit(Blocked, &rdev->flags),
6238 			   msecs_to_jiffies(5000));
6239 	rdev_dec_pending(rdev, mddev);
6240 }
6241 EXPORT_SYMBOL(md_wait_for_blocked_rdev);
6242 
6243 static int md_notify_reboot(struct notifier_block *this,
6244 			    unsigned long code, void *x)
6245 {
6246 	struct list_head *tmp;
6247 	mddev_t *mddev;
6248 
6249 	if ((code == SYS_DOWN) || (code == SYS_HALT) || (code == SYS_POWER_OFF)) {
6250 
6251 		printk(KERN_INFO "md: stopping all md devices.\n");
6252 
6253 		for_each_mddev(mddev, tmp)
6254 			if (mddev_trylock(mddev)) {
6255 				/* Force a switch to readonly even array
6256 				 * appears to still be in use.  Hence
6257 				 * the '100'.
6258 				 */
6259 				do_md_stop(mddev, 1, 100);
6260 				mddev_unlock(mddev);
6261 			}
6262 		/*
6263 		 * certain more exotic SCSI devices are known to be
6264 		 * volatile wrt too early system reboots. While the
6265 		 * right place to handle this issue is the given
6266 		 * driver, we do want to have a safe RAID driver ...
6267 		 */
6268 		mdelay(1000*1);
6269 	}
6270 	return NOTIFY_DONE;
6271 }
6272 
6273 static struct notifier_block md_notifier = {
6274 	.notifier_call	= md_notify_reboot,
6275 	.next		= NULL,
6276 	.priority	= INT_MAX, /* before any real devices */
6277 };
6278 
6279 static void md_geninit(void)
6280 {
6281 	dprintk("md: sizeof(mdp_super_t) = %d\n", (int)sizeof(mdp_super_t));
6282 
6283 	proc_create("mdstat", S_IRUGO, NULL, &md_seq_fops);
6284 }
6285 
6286 static int __init md_init(void)
6287 {
6288 	if (register_blkdev(MAJOR_NR, "md"))
6289 		return -1;
6290 	if ((mdp_major=register_blkdev(0, "mdp"))<=0) {
6291 		unregister_blkdev(MAJOR_NR, "md");
6292 		return -1;
6293 	}
6294 	blk_register_region(MKDEV(MAJOR_NR, 0), 1UL<<MINORBITS, THIS_MODULE,
6295 			    md_probe, NULL, NULL);
6296 	blk_register_region(MKDEV(mdp_major, 0), 1UL<<MINORBITS, THIS_MODULE,
6297 			    md_probe, NULL, NULL);
6298 
6299 	register_reboot_notifier(&md_notifier);
6300 	raid_table_header = register_sysctl_table(raid_root_table);
6301 
6302 	md_geninit();
6303 	return 0;
6304 }
6305 
6306 
6307 #ifndef MODULE
6308 
6309 /*
6310  * Searches all registered partitions for autorun RAID arrays
6311  * at boot time.
6312  */
6313 
6314 static LIST_HEAD(all_detected_devices);
6315 struct detected_devices_node {
6316 	struct list_head list;
6317 	dev_t dev;
6318 };
6319 
6320 void md_autodetect_dev(dev_t dev)
6321 {
6322 	struct detected_devices_node *node_detected_dev;
6323 
6324 	node_detected_dev = kzalloc(sizeof(*node_detected_dev), GFP_KERNEL);
6325 	if (node_detected_dev) {
6326 		node_detected_dev->dev = dev;
6327 		list_add_tail(&node_detected_dev->list, &all_detected_devices);
6328 	} else {
6329 		printk(KERN_CRIT "md: md_autodetect_dev: kzalloc failed"
6330 			", skipping dev(%d,%d)\n", MAJOR(dev), MINOR(dev));
6331 	}
6332 }
6333 
6334 
6335 static void autostart_arrays(int part)
6336 {
6337 	mdk_rdev_t *rdev;
6338 	struct detected_devices_node *node_detected_dev;
6339 	dev_t dev;
6340 	int i_scanned, i_passed;
6341 
6342 	i_scanned = 0;
6343 	i_passed = 0;
6344 
6345 	printk(KERN_INFO "md: Autodetecting RAID arrays.\n");
6346 
6347 	while (!list_empty(&all_detected_devices) && i_scanned < INT_MAX) {
6348 		i_scanned++;
6349 		node_detected_dev = list_entry(all_detected_devices.next,
6350 					struct detected_devices_node, list);
6351 		list_del(&node_detected_dev->list);
6352 		dev = node_detected_dev->dev;
6353 		kfree(node_detected_dev);
6354 		rdev = md_import_device(dev,0, 90);
6355 		if (IS_ERR(rdev))
6356 			continue;
6357 
6358 		if (test_bit(Faulty, &rdev->flags)) {
6359 			MD_BUG();
6360 			continue;
6361 		}
6362 		set_bit(AutoDetected, &rdev->flags);
6363 		list_add(&rdev->same_set, &pending_raid_disks);
6364 		i_passed++;
6365 	}
6366 
6367 	printk(KERN_INFO "md: Scanned %d and added %d devices.\n",
6368 						i_scanned, i_passed);
6369 
6370 	autorun_devices(part);
6371 }
6372 
6373 #endif /* !MODULE */
6374 
6375 static __exit void md_exit(void)
6376 {
6377 	mddev_t *mddev;
6378 	struct list_head *tmp;
6379 
6380 	blk_unregister_region(MKDEV(MAJOR_NR,0), 1U << MINORBITS);
6381 	blk_unregister_region(MKDEV(mdp_major,0), 1U << MINORBITS);
6382 
6383 	unregister_blkdev(MAJOR_NR,"md");
6384 	unregister_blkdev(mdp_major, "mdp");
6385 	unregister_reboot_notifier(&md_notifier);
6386 	unregister_sysctl_table(raid_table_header);
6387 	remove_proc_entry("mdstat", NULL);
6388 	for_each_mddev(mddev, tmp) {
6389 		struct gendisk *disk = mddev->gendisk;
6390 		if (!disk)
6391 			continue;
6392 		export_array(mddev);
6393 		del_gendisk(disk);
6394 		put_disk(disk);
6395 		mddev->gendisk = NULL;
6396 		mddev_put(mddev);
6397 	}
6398 }
6399 
6400 subsys_initcall(md_init);
6401 module_exit(md_exit)
6402 
6403 static int get_ro(char *buffer, struct kernel_param *kp)
6404 {
6405 	return sprintf(buffer, "%d", start_readonly);
6406 }
6407 static int set_ro(const char *val, struct kernel_param *kp)
6408 {
6409 	char *e;
6410 	int num = simple_strtoul(val, &e, 10);
6411 	if (*val && (*e == '\0' || *e == '\n')) {
6412 		start_readonly = num;
6413 		return 0;
6414 	}
6415 	return -EINVAL;
6416 }
6417 
6418 module_param_call(start_ro, set_ro, get_ro, NULL, S_IRUSR|S_IWUSR);
6419 module_param(start_dirty_degraded, int, S_IRUGO|S_IWUSR);
6420 
6421 
6422 EXPORT_SYMBOL(register_md_personality);
6423 EXPORT_SYMBOL(unregister_md_personality);
6424 EXPORT_SYMBOL(md_error);
6425 EXPORT_SYMBOL(md_done_sync);
6426 EXPORT_SYMBOL(md_write_start);
6427 EXPORT_SYMBOL(md_write_end);
6428 EXPORT_SYMBOL(md_register_thread);
6429 EXPORT_SYMBOL(md_unregister_thread);
6430 EXPORT_SYMBOL(md_wakeup_thread);
6431 EXPORT_SYMBOL(md_check_recovery);
6432 MODULE_LICENSE("GPL");
6433 MODULE_ALIAS("md");
6434 MODULE_ALIAS_BLOCKDEV_MAJOR(MD_MAJOR);
6435