xref: /linux/drivers/md/md.c (revision c0c9209ddd96bc4f1d70a8b9958710671e076080)
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/module.h>
36 #include <linux/kernel.h>
37 #include <linux/kthread.h>
38 #include <linux/linkage.h>
39 #include <linux/raid/md.h>
40 #include <linux/raid/bitmap.h>
41 #include <linux/sysctl.h>
42 #include <linux/buffer_head.h> /* for invalidate_bdev */
43 #include <linux/poll.h>
44 #include <linux/mutex.h>
45 #include <linux/ctype.h>
46 #include <linux/freezer.h>
47 
48 #include <linux/init.h>
49 
50 #include <linux/file.h>
51 
52 #ifdef CONFIG_KMOD
53 #include <linux/kmod.h>
54 #endif
55 
56 #include <asm/unaligned.h>
57 
58 #define MAJOR_NR MD_MAJOR
59 #define MD_DRIVER
60 
61 /* 63 partitions with the alternate major number (mdp) */
62 #define MdpMinorShift 6
63 
64 #define DEBUG 0
65 #define dprintk(x...) ((void)(DEBUG && printk(x)))
66 
67 
68 #ifndef MODULE
69 static void autostart_arrays (int part);
70 #endif
71 
72 static LIST_HEAD(pers_list);
73 static DEFINE_SPINLOCK(pers_lock);
74 
75 static void md_print_devices(void);
76 
77 static DECLARE_WAIT_QUEUE_HEAD(resync_wait);
78 
79 #define MD_BUG(x...) { printk("md: bug in file %s, line %d\n", __FILE__, __LINE__); md_print_devices(); }
80 
81 /*
82  * Current RAID-1,4,5 parallel reconstruction 'guaranteed speed limit'
83  * is 1000 KB/sec, so the extra system load does not show up that much.
84  * Increase it if you want to have more _guaranteed_ speed. Note that
85  * the RAID driver will use the maximum available bandwidth if the IO
86  * subsystem is idle. There is also an 'absolute maximum' reconstruction
87  * speed limit - in case reconstruction slows down your system despite
88  * idle IO detection.
89  *
90  * you can change it via /proc/sys/dev/raid/speed_limit_min and _max.
91  * or /sys/block/mdX/md/sync_speed_{min,max}
92  */
93 
94 static int sysctl_speed_limit_min = 1000;
95 static int sysctl_speed_limit_max = 200000;
96 static inline int speed_min(mddev_t *mddev)
97 {
98 	return mddev->sync_speed_min ?
99 		mddev->sync_speed_min : sysctl_speed_limit_min;
100 }
101 
102 static inline int speed_max(mddev_t *mddev)
103 {
104 	return mddev->sync_speed_max ?
105 		mddev->sync_speed_max : sysctl_speed_limit_max;
106 }
107 
108 static struct ctl_table_header *raid_table_header;
109 
110 static ctl_table raid_table[] = {
111 	{
112 		.ctl_name	= DEV_RAID_SPEED_LIMIT_MIN,
113 		.procname	= "speed_limit_min",
114 		.data		= &sysctl_speed_limit_min,
115 		.maxlen		= sizeof(int),
116 		.mode		= S_IRUGO|S_IWUSR,
117 		.proc_handler	= &proc_dointvec,
118 	},
119 	{
120 		.ctl_name	= DEV_RAID_SPEED_LIMIT_MAX,
121 		.procname	= "speed_limit_max",
122 		.data		= &sysctl_speed_limit_max,
123 		.maxlen		= sizeof(int),
124 		.mode		= S_IRUGO|S_IWUSR,
125 		.proc_handler	= &proc_dointvec,
126 	},
127 	{ .ctl_name = 0 }
128 };
129 
130 static ctl_table raid_dir_table[] = {
131 	{
132 		.ctl_name	= DEV_RAID,
133 		.procname	= "raid",
134 		.maxlen		= 0,
135 		.mode		= S_IRUGO|S_IXUGO,
136 		.child		= raid_table,
137 	},
138 	{ .ctl_name = 0 }
139 };
140 
141 static ctl_table raid_root_table[] = {
142 	{
143 		.ctl_name	= CTL_DEV,
144 		.procname	= "dev",
145 		.maxlen		= 0,
146 		.mode		= 0555,
147 		.child		= raid_dir_table,
148 	},
149 	{ .ctl_name = 0 }
150 };
151 
152 static struct block_device_operations md_fops;
153 
154 static int start_readonly;
155 
156 /*
157  * We have a system wide 'event count' that is incremented
158  * on any 'interesting' event, and readers of /proc/mdstat
159  * can use 'poll' or 'select' to find out when the event
160  * count increases.
161  *
162  * Events are:
163  *  start array, stop array, error, add device, remove device,
164  *  start build, activate spare
165  */
166 static DECLARE_WAIT_QUEUE_HEAD(md_event_waiters);
167 static atomic_t md_event_count;
168 void md_new_event(mddev_t *mddev)
169 {
170 	atomic_inc(&md_event_count);
171 	wake_up(&md_event_waiters);
172 }
173 EXPORT_SYMBOL_GPL(md_new_event);
174 
175 /* Alternate version that can be called from interrupts
176  * when calling sysfs_notify isn't needed.
177  */
178 static void md_new_event_inintr(mddev_t *mddev)
179 {
180 	atomic_inc(&md_event_count);
181 	wake_up(&md_event_waiters);
182 }
183 
184 /*
185  * Enables to iterate over all existing md arrays
186  * all_mddevs_lock protects this list.
187  */
188 static LIST_HEAD(all_mddevs);
189 static DEFINE_SPINLOCK(all_mddevs_lock);
190 
191 
192 /*
193  * iterates through all used mddevs in the system.
194  * We take care to grab the all_mddevs_lock whenever navigating
195  * the list, and to always hold a refcount when unlocked.
196  * Any code which breaks out of this loop while own
197  * a reference to the current mddev and must mddev_put it.
198  */
199 #define for_each_mddev(mddev,tmp)					\
200 									\
201 	for (({ spin_lock(&all_mddevs_lock); 				\
202 		tmp = all_mddevs.next;					\
203 		mddev = NULL;});					\
204 	     ({ if (tmp != &all_mddevs)					\
205 			mddev_get(list_entry(tmp, mddev_t, all_mddevs));\
206 		spin_unlock(&all_mddevs_lock);				\
207 		if (mddev) mddev_put(mddev);				\
208 		mddev = list_entry(tmp, mddev_t, all_mddevs);		\
209 		tmp != &all_mddevs;});					\
210 	     ({ spin_lock(&all_mddevs_lock);				\
211 		tmp = tmp->next;})					\
212 		)
213 
214 
215 static int md_fail_request (struct request_queue *q, struct bio *bio)
216 {
217 	bio_io_error(bio);
218 	return 0;
219 }
220 
221 static inline mddev_t *mddev_get(mddev_t *mddev)
222 {
223 	atomic_inc(&mddev->active);
224 	return mddev;
225 }
226 
227 static void mddev_put(mddev_t *mddev)
228 {
229 	if (!atomic_dec_and_lock(&mddev->active, &all_mddevs_lock))
230 		return;
231 	if (!mddev->raid_disks && list_empty(&mddev->disks)) {
232 		list_del(&mddev->all_mddevs);
233 		spin_unlock(&all_mddevs_lock);
234 		blk_cleanup_queue(mddev->queue);
235 		kobject_put(&mddev->kobj);
236 	} else
237 		spin_unlock(&all_mddevs_lock);
238 }
239 
240 static mddev_t * mddev_find(dev_t unit)
241 {
242 	mddev_t *mddev, *new = NULL;
243 
244  retry:
245 	spin_lock(&all_mddevs_lock);
246 	list_for_each_entry(mddev, &all_mddevs, all_mddevs)
247 		if (mddev->unit == unit) {
248 			mddev_get(mddev);
249 			spin_unlock(&all_mddevs_lock);
250 			kfree(new);
251 			return mddev;
252 		}
253 
254 	if (new) {
255 		list_add(&new->all_mddevs, &all_mddevs);
256 		spin_unlock(&all_mddevs_lock);
257 		return new;
258 	}
259 	spin_unlock(&all_mddevs_lock);
260 
261 	new = kzalloc(sizeof(*new), GFP_KERNEL);
262 	if (!new)
263 		return NULL;
264 
265 	new->unit = unit;
266 	if (MAJOR(unit) == MD_MAJOR)
267 		new->md_minor = MINOR(unit);
268 	else
269 		new->md_minor = MINOR(unit) >> MdpMinorShift;
270 
271 	mutex_init(&new->reconfig_mutex);
272 	INIT_LIST_HEAD(&new->disks);
273 	INIT_LIST_HEAD(&new->all_mddevs);
274 	init_timer(&new->safemode_timer);
275 	atomic_set(&new->active, 1);
276 	atomic_set(&new->openers, 0);
277 	spin_lock_init(&new->write_lock);
278 	init_waitqueue_head(&new->sb_wait);
279 	init_waitqueue_head(&new->recovery_wait);
280 	new->reshape_position = MaxSector;
281 	new->resync_min = 0;
282 	new->resync_max = MaxSector;
283 	new->level = LEVEL_NONE;
284 
285 	new->queue = blk_alloc_queue(GFP_KERNEL);
286 	if (!new->queue) {
287 		kfree(new);
288 		return NULL;
289 	}
290 	/* Can be unlocked because the queue is new: no concurrency */
291 	queue_flag_set_unlocked(QUEUE_FLAG_CLUSTER, new->queue);
292 
293 	blk_queue_make_request(new->queue, md_fail_request);
294 
295 	goto retry;
296 }
297 
298 static inline int mddev_lock(mddev_t * mddev)
299 {
300 	return mutex_lock_interruptible(&mddev->reconfig_mutex);
301 }
302 
303 static inline int mddev_trylock(mddev_t * mddev)
304 {
305 	return mutex_trylock(&mddev->reconfig_mutex);
306 }
307 
308 static inline void mddev_unlock(mddev_t * mddev)
309 {
310 	mutex_unlock(&mddev->reconfig_mutex);
311 
312 	md_wakeup_thread(mddev->thread);
313 }
314 
315 static mdk_rdev_t * find_rdev_nr(mddev_t *mddev, int nr)
316 {
317 	mdk_rdev_t * rdev;
318 	struct list_head *tmp;
319 
320 	rdev_for_each(rdev, tmp, mddev) {
321 		if (rdev->desc_nr == nr)
322 			return rdev;
323 	}
324 	return NULL;
325 }
326 
327 static mdk_rdev_t * find_rdev(mddev_t * mddev, dev_t dev)
328 {
329 	struct list_head *tmp;
330 	mdk_rdev_t *rdev;
331 
332 	rdev_for_each(rdev, tmp, mddev) {
333 		if (rdev->bdev->bd_dev == dev)
334 			return rdev;
335 	}
336 	return NULL;
337 }
338 
339 static struct mdk_personality *find_pers(int level, char *clevel)
340 {
341 	struct mdk_personality *pers;
342 	list_for_each_entry(pers, &pers_list, list) {
343 		if (level != LEVEL_NONE && pers->level == level)
344 			return pers;
345 		if (strcmp(pers->name, clevel)==0)
346 			return pers;
347 	}
348 	return NULL;
349 }
350 
351 /* return the offset of the super block in 512byte sectors */
352 static inline sector_t calc_dev_sboffset(struct block_device *bdev)
353 {
354 	sector_t num_sectors = bdev->bd_inode->i_size / 512;
355 	return MD_NEW_SIZE_SECTORS(num_sectors);
356 }
357 
358 static sector_t calc_num_sectors(mdk_rdev_t *rdev, unsigned chunk_size)
359 {
360 	sector_t num_sectors = rdev->sb_start;
361 
362 	if (chunk_size)
363 		num_sectors &= ~((sector_t)chunk_size/512 - 1);
364 	return num_sectors;
365 }
366 
367 static int alloc_disk_sb(mdk_rdev_t * rdev)
368 {
369 	if (rdev->sb_page)
370 		MD_BUG();
371 
372 	rdev->sb_page = alloc_page(GFP_KERNEL);
373 	if (!rdev->sb_page) {
374 		printk(KERN_ALERT "md: out of memory.\n");
375 		return -ENOMEM;
376 	}
377 
378 	return 0;
379 }
380 
381 static void free_disk_sb(mdk_rdev_t * rdev)
382 {
383 	if (rdev->sb_page) {
384 		put_page(rdev->sb_page);
385 		rdev->sb_loaded = 0;
386 		rdev->sb_page = NULL;
387 		rdev->sb_start = 0;
388 		rdev->size = 0;
389 	}
390 }
391 
392 
393 static void super_written(struct bio *bio, int error)
394 {
395 	mdk_rdev_t *rdev = bio->bi_private;
396 	mddev_t *mddev = rdev->mddev;
397 
398 	if (error || !test_bit(BIO_UPTODATE, &bio->bi_flags)) {
399 		printk("md: super_written gets error=%d, uptodate=%d\n",
400 		       error, test_bit(BIO_UPTODATE, &bio->bi_flags));
401 		WARN_ON(test_bit(BIO_UPTODATE, &bio->bi_flags));
402 		md_error(mddev, rdev);
403 	}
404 
405 	if (atomic_dec_and_test(&mddev->pending_writes))
406 		wake_up(&mddev->sb_wait);
407 	bio_put(bio);
408 }
409 
410 static void super_written_barrier(struct bio *bio, int error)
411 {
412 	struct bio *bio2 = bio->bi_private;
413 	mdk_rdev_t *rdev = bio2->bi_private;
414 	mddev_t *mddev = rdev->mddev;
415 
416 	if (!test_bit(BIO_UPTODATE, &bio->bi_flags) &&
417 	    error == -EOPNOTSUPP) {
418 		unsigned long flags;
419 		/* barriers don't appear to be supported :-( */
420 		set_bit(BarriersNotsupp, &rdev->flags);
421 		mddev->barriers_work = 0;
422 		spin_lock_irqsave(&mddev->write_lock, flags);
423 		bio2->bi_next = mddev->biolist;
424 		mddev->biolist = bio2;
425 		spin_unlock_irqrestore(&mddev->write_lock, flags);
426 		wake_up(&mddev->sb_wait);
427 		bio_put(bio);
428 	} else {
429 		bio_put(bio2);
430 		bio->bi_private = rdev;
431 		super_written(bio, error);
432 	}
433 }
434 
435 void md_super_write(mddev_t *mddev, mdk_rdev_t *rdev,
436 		   sector_t sector, int size, struct page *page)
437 {
438 	/* write first size bytes of page to sector of rdev
439 	 * Increment mddev->pending_writes before returning
440 	 * and decrement it on completion, waking up sb_wait
441 	 * if zero is reached.
442 	 * If an error occurred, call md_error
443 	 *
444 	 * As we might need to resubmit the request if BIO_RW_BARRIER
445 	 * causes ENOTSUPP, we allocate a spare bio...
446 	 */
447 	struct bio *bio = bio_alloc(GFP_NOIO, 1);
448 	int rw = (1<<BIO_RW) | (1<<BIO_RW_SYNC);
449 
450 	bio->bi_bdev = rdev->bdev;
451 	bio->bi_sector = sector;
452 	bio_add_page(bio, page, size, 0);
453 	bio->bi_private = rdev;
454 	bio->bi_end_io = super_written;
455 	bio->bi_rw = rw;
456 
457 	atomic_inc(&mddev->pending_writes);
458 	if (!test_bit(BarriersNotsupp, &rdev->flags)) {
459 		struct bio *rbio;
460 		rw |= (1<<BIO_RW_BARRIER);
461 		rbio = bio_clone(bio, GFP_NOIO);
462 		rbio->bi_private = bio;
463 		rbio->bi_end_io = super_written_barrier;
464 		submit_bio(rw, rbio);
465 	} else
466 		submit_bio(rw, bio);
467 }
468 
469 void md_super_wait(mddev_t *mddev)
470 {
471 	/* wait for all superblock writes that were scheduled to complete.
472 	 * if any had to be retried (due to BARRIER problems), retry them
473 	 */
474 	DEFINE_WAIT(wq);
475 	for(;;) {
476 		prepare_to_wait(&mddev->sb_wait, &wq, TASK_UNINTERRUPTIBLE);
477 		if (atomic_read(&mddev->pending_writes)==0)
478 			break;
479 		while (mddev->biolist) {
480 			struct bio *bio;
481 			spin_lock_irq(&mddev->write_lock);
482 			bio = mddev->biolist;
483 			mddev->biolist = bio->bi_next ;
484 			bio->bi_next = NULL;
485 			spin_unlock_irq(&mddev->write_lock);
486 			submit_bio(bio->bi_rw, bio);
487 		}
488 		schedule();
489 	}
490 	finish_wait(&mddev->sb_wait, &wq);
491 }
492 
493 static void bi_complete(struct bio *bio, int error)
494 {
495 	complete((struct completion*)bio->bi_private);
496 }
497 
498 int sync_page_io(struct block_device *bdev, sector_t sector, int size,
499 		   struct page *page, int rw)
500 {
501 	struct bio *bio = bio_alloc(GFP_NOIO, 1);
502 	struct completion event;
503 	int ret;
504 
505 	rw |= (1 << BIO_RW_SYNC);
506 
507 	bio->bi_bdev = bdev;
508 	bio->bi_sector = sector;
509 	bio_add_page(bio, page, size, 0);
510 	init_completion(&event);
511 	bio->bi_private = &event;
512 	bio->bi_end_io = bi_complete;
513 	submit_bio(rw, bio);
514 	wait_for_completion(&event);
515 
516 	ret = test_bit(BIO_UPTODATE, &bio->bi_flags);
517 	bio_put(bio);
518 	return ret;
519 }
520 EXPORT_SYMBOL_GPL(sync_page_io);
521 
522 static int read_disk_sb(mdk_rdev_t * rdev, int size)
523 {
524 	char b[BDEVNAME_SIZE];
525 	if (!rdev->sb_page) {
526 		MD_BUG();
527 		return -EINVAL;
528 	}
529 	if (rdev->sb_loaded)
530 		return 0;
531 
532 
533 	if (!sync_page_io(rdev->bdev, rdev->sb_start, size, rdev->sb_page, READ))
534 		goto fail;
535 	rdev->sb_loaded = 1;
536 	return 0;
537 
538 fail:
539 	printk(KERN_WARNING "md: disabled device %s, could not read superblock.\n",
540 		bdevname(rdev->bdev,b));
541 	return -EINVAL;
542 }
543 
544 static int uuid_equal(mdp_super_t *sb1, mdp_super_t *sb2)
545 {
546 	return 	sb1->set_uuid0 == sb2->set_uuid0 &&
547 		sb1->set_uuid1 == sb2->set_uuid1 &&
548 		sb1->set_uuid2 == sb2->set_uuid2 &&
549 		sb1->set_uuid3 == sb2->set_uuid3;
550 }
551 
552 static int sb_equal(mdp_super_t *sb1, mdp_super_t *sb2)
553 {
554 	int ret;
555 	mdp_super_t *tmp1, *tmp2;
556 
557 	tmp1 = kmalloc(sizeof(*tmp1),GFP_KERNEL);
558 	tmp2 = kmalloc(sizeof(*tmp2),GFP_KERNEL);
559 
560 	if (!tmp1 || !tmp2) {
561 		ret = 0;
562 		printk(KERN_INFO "md.c sb_equal(): failed to allocate memory!\n");
563 		goto abort;
564 	}
565 
566 	*tmp1 = *sb1;
567 	*tmp2 = *sb2;
568 
569 	/*
570 	 * nr_disks is not constant
571 	 */
572 	tmp1->nr_disks = 0;
573 	tmp2->nr_disks = 0;
574 
575 	ret = (memcmp(tmp1, tmp2, MD_SB_GENERIC_CONSTANT_WORDS * 4) == 0);
576 abort:
577 	kfree(tmp1);
578 	kfree(tmp2);
579 	return ret;
580 }
581 
582 
583 static u32 md_csum_fold(u32 csum)
584 {
585 	csum = (csum & 0xffff) + (csum >> 16);
586 	return (csum & 0xffff) + (csum >> 16);
587 }
588 
589 static unsigned int calc_sb_csum(mdp_super_t * sb)
590 {
591 	u64 newcsum = 0;
592 	u32 *sb32 = (u32*)sb;
593 	int i;
594 	unsigned int disk_csum, csum;
595 
596 	disk_csum = sb->sb_csum;
597 	sb->sb_csum = 0;
598 
599 	for (i = 0; i < MD_SB_BYTES/4 ; i++)
600 		newcsum += sb32[i];
601 	csum = (newcsum & 0xffffffff) + (newcsum>>32);
602 
603 
604 #ifdef CONFIG_ALPHA
605 	/* This used to use csum_partial, which was wrong for several
606 	 * reasons including that different results are returned on
607 	 * different architectures.  It isn't critical that we get exactly
608 	 * the same return value as before (we always csum_fold before
609 	 * testing, and that removes any differences).  However as we
610 	 * know that csum_partial always returned a 16bit value on
611 	 * alphas, do a fold to maximise conformity to previous behaviour.
612 	 */
613 	sb->sb_csum = md_csum_fold(disk_csum);
614 #else
615 	sb->sb_csum = disk_csum;
616 #endif
617 	return csum;
618 }
619 
620 
621 /*
622  * Handle superblock details.
623  * We want to be able to handle multiple superblock formats
624  * so we have a common interface to them all, and an array of
625  * different handlers.
626  * We rely on user-space to write the initial superblock, and support
627  * reading and updating of superblocks.
628  * Interface methods are:
629  *   int load_super(mdk_rdev_t *dev, mdk_rdev_t *refdev, int minor_version)
630  *      loads and validates a superblock on dev.
631  *      if refdev != NULL, compare superblocks on both devices
632  *    Return:
633  *      0 - dev has a superblock that is compatible with refdev
634  *      1 - dev has a superblock that is compatible and newer than refdev
635  *          so dev should be used as the refdev in future
636  *     -EINVAL superblock incompatible or invalid
637  *     -othererror e.g. -EIO
638  *
639  *   int validate_super(mddev_t *mddev, mdk_rdev_t *dev)
640  *      Verify that dev is acceptable into mddev.
641  *       The first time, mddev->raid_disks will be 0, and data from
642  *       dev should be merged in.  Subsequent calls check that dev
643  *       is new enough.  Return 0 or -EINVAL
644  *
645  *   void sync_super(mddev_t *mddev, mdk_rdev_t *dev)
646  *     Update the superblock for rdev with data in mddev
647  *     This does not write to disc.
648  *
649  */
650 
651 struct super_type  {
652 	char		    *name;
653 	struct module	    *owner;
654 	int		    (*load_super)(mdk_rdev_t *rdev, mdk_rdev_t *refdev,
655 					  int minor_version);
656 	int		    (*validate_super)(mddev_t *mddev, mdk_rdev_t *rdev);
657 	void		    (*sync_super)(mddev_t *mddev, mdk_rdev_t *rdev);
658 	unsigned long long  (*rdev_size_change)(mdk_rdev_t *rdev,
659 						sector_t num_sectors);
660 };
661 
662 /*
663  * load_super for 0.90.0
664  */
665 static int super_90_load(mdk_rdev_t *rdev, mdk_rdev_t *refdev, int minor_version)
666 {
667 	char b[BDEVNAME_SIZE], b2[BDEVNAME_SIZE];
668 	mdp_super_t *sb;
669 	int ret;
670 
671 	/*
672 	 * Calculate the position of the superblock (512byte sectors),
673 	 * it's at the end of the disk.
674 	 *
675 	 * It also happens to be a multiple of 4Kb.
676 	 */
677 	rdev->sb_start = calc_dev_sboffset(rdev->bdev);
678 
679 	ret = read_disk_sb(rdev, MD_SB_BYTES);
680 	if (ret) return ret;
681 
682 	ret = -EINVAL;
683 
684 	bdevname(rdev->bdev, b);
685 	sb = (mdp_super_t*)page_address(rdev->sb_page);
686 
687 	if (sb->md_magic != MD_SB_MAGIC) {
688 		printk(KERN_ERR "md: invalid raid superblock magic on %s\n",
689 		       b);
690 		goto abort;
691 	}
692 
693 	if (sb->major_version != 0 ||
694 	    sb->minor_version < 90 ||
695 	    sb->minor_version > 91) {
696 		printk(KERN_WARNING "Bad version number %d.%d on %s\n",
697 			sb->major_version, sb->minor_version,
698 			b);
699 		goto abort;
700 	}
701 
702 	if (sb->raid_disks <= 0)
703 		goto abort;
704 
705 	if (md_csum_fold(calc_sb_csum(sb)) != md_csum_fold(sb->sb_csum)) {
706 		printk(KERN_WARNING "md: invalid superblock checksum on %s\n",
707 			b);
708 		goto abort;
709 	}
710 
711 	rdev->preferred_minor = sb->md_minor;
712 	rdev->data_offset = 0;
713 	rdev->sb_size = MD_SB_BYTES;
714 
715 	if (sb->state & (1<<MD_SB_BITMAP_PRESENT)) {
716 		if (sb->level != 1 && sb->level != 4
717 		    && sb->level != 5 && sb->level != 6
718 		    && sb->level != 10) {
719 			/* FIXME use a better test */
720 			printk(KERN_WARNING
721 			       "md: bitmaps not supported for this level.\n");
722 			goto abort;
723 		}
724 	}
725 
726 	if (sb->level == LEVEL_MULTIPATH)
727 		rdev->desc_nr = -1;
728 	else
729 		rdev->desc_nr = sb->this_disk.number;
730 
731 	if (!refdev) {
732 		ret = 1;
733 	} else {
734 		__u64 ev1, ev2;
735 		mdp_super_t *refsb = (mdp_super_t*)page_address(refdev->sb_page);
736 		if (!uuid_equal(refsb, sb)) {
737 			printk(KERN_WARNING "md: %s has different UUID to %s\n",
738 				b, bdevname(refdev->bdev,b2));
739 			goto abort;
740 		}
741 		if (!sb_equal(refsb, sb)) {
742 			printk(KERN_WARNING "md: %s has same UUID"
743 			       " but different superblock to %s\n",
744 			       b, bdevname(refdev->bdev, b2));
745 			goto abort;
746 		}
747 		ev1 = md_event(sb);
748 		ev2 = md_event(refsb);
749 		if (ev1 > ev2)
750 			ret = 1;
751 		else
752 			ret = 0;
753 	}
754 	rdev->size = calc_num_sectors(rdev, sb->chunk_size) / 2;
755 
756 	if (rdev->size < sb->size && sb->level > 1)
757 		/* "this cannot possibly happen" ... */
758 		ret = -EINVAL;
759 
760  abort:
761 	return ret;
762 }
763 
764 /*
765  * validate_super for 0.90.0
766  */
767 static int super_90_validate(mddev_t *mddev, mdk_rdev_t *rdev)
768 {
769 	mdp_disk_t *desc;
770 	mdp_super_t *sb = (mdp_super_t *)page_address(rdev->sb_page);
771 	__u64 ev1 = md_event(sb);
772 
773 	rdev->raid_disk = -1;
774 	clear_bit(Faulty, &rdev->flags);
775 	clear_bit(In_sync, &rdev->flags);
776 	clear_bit(WriteMostly, &rdev->flags);
777 	clear_bit(BarriersNotsupp, &rdev->flags);
778 
779 	if (mddev->raid_disks == 0) {
780 		mddev->major_version = 0;
781 		mddev->minor_version = sb->minor_version;
782 		mddev->patch_version = sb->patch_version;
783 		mddev->external = 0;
784 		mddev->chunk_size = sb->chunk_size;
785 		mddev->ctime = sb->ctime;
786 		mddev->utime = sb->utime;
787 		mddev->level = sb->level;
788 		mddev->clevel[0] = 0;
789 		mddev->layout = sb->layout;
790 		mddev->raid_disks = sb->raid_disks;
791 		mddev->size = sb->size;
792 		mddev->events = ev1;
793 		mddev->bitmap_offset = 0;
794 		mddev->default_bitmap_offset = MD_SB_BYTES >> 9;
795 
796 		if (mddev->minor_version >= 91) {
797 			mddev->reshape_position = sb->reshape_position;
798 			mddev->delta_disks = sb->delta_disks;
799 			mddev->new_level = sb->new_level;
800 			mddev->new_layout = sb->new_layout;
801 			mddev->new_chunk = sb->new_chunk;
802 		} else {
803 			mddev->reshape_position = MaxSector;
804 			mddev->delta_disks = 0;
805 			mddev->new_level = mddev->level;
806 			mddev->new_layout = mddev->layout;
807 			mddev->new_chunk = mddev->chunk_size;
808 		}
809 
810 		if (sb->state & (1<<MD_SB_CLEAN))
811 			mddev->recovery_cp = MaxSector;
812 		else {
813 			if (sb->events_hi == sb->cp_events_hi &&
814 				sb->events_lo == sb->cp_events_lo) {
815 				mddev->recovery_cp = sb->recovery_cp;
816 			} else
817 				mddev->recovery_cp = 0;
818 		}
819 
820 		memcpy(mddev->uuid+0, &sb->set_uuid0, 4);
821 		memcpy(mddev->uuid+4, &sb->set_uuid1, 4);
822 		memcpy(mddev->uuid+8, &sb->set_uuid2, 4);
823 		memcpy(mddev->uuid+12,&sb->set_uuid3, 4);
824 
825 		mddev->max_disks = MD_SB_DISKS;
826 
827 		if (sb->state & (1<<MD_SB_BITMAP_PRESENT) &&
828 		    mddev->bitmap_file == NULL)
829 			mddev->bitmap_offset = mddev->default_bitmap_offset;
830 
831 	} else if (mddev->pers == NULL) {
832 		/* Insist on good event counter while assembling */
833 		++ev1;
834 		if (ev1 < mddev->events)
835 			return -EINVAL;
836 	} else if (mddev->bitmap) {
837 		/* if adding to array with a bitmap, then we can accept an
838 		 * older device ... but not too old.
839 		 */
840 		if (ev1 < mddev->bitmap->events_cleared)
841 			return 0;
842 	} else {
843 		if (ev1 < mddev->events)
844 			/* just a hot-add of a new device, leave raid_disk at -1 */
845 			return 0;
846 	}
847 
848 	if (mddev->level != LEVEL_MULTIPATH) {
849 		desc = sb->disks + rdev->desc_nr;
850 
851 		if (desc->state & (1<<MD_DISK_FAULTY))
852 			set_bit(Faulty, &rdev->flags);
853 		else if (desc->state & (1<<MD_DISK_SYNC) /* &&
854 			    desc->raid_disk < mddev->raid_disks */) {
855 			set_bit(In_sync, &rdev->flags);
856 			rdev->raid_disk = desc->raid_disk;
857 		}
858 		if (desc->state & (1<<MD_DISK_WRITEMOSTLY))
859 			set_bit(WriteMostly, &rdev->flags);
860 	} else /* MULTIPATH are always insync */
861 		set_bit(In_sync, &rdev->flags);
862 	return 0;
863 }
864 
865 /*
866  * sync_super for 0.90.0
867  */
868 static void super_90_sync(mddev_t *mddev, mdk_rdev_t *rdev)
869 {
870 	mdp_super_t *sb;
871 	struct list_head *tmp;
872 	mdk_rdev_t *rdev2;
873 	int next_spare = mddev->raid_disks;
874 
875 
876 	/* make rdev->sb match mddev data..
877 	 *
878 	 * 1/ zero out disks
879 	 * 2/ Add info for each disk, keeping track of highest desc_nr (next_spare);
880 	 * 3/ any empty disks < next_spare become removed
881 	 *
882 	 * disks[0] gets initialised to REMOVED because
883 	 * we cannot be sure from other fields if it has
884 	 * been initialised or not.
885 	 */
886 	int i;
887 	int active=0, working=0,failed=0,spare=0,nr_disks=0;
888 
889 	rdev->sb_size = MD_SB_BYTES;
890 
891 	sb = (mdp_super_t*)page_address(rdev->sb_page);
892 
893 	memset(sb, 0, sizeof(*sb));
894 
895 	sb->md_magic = MD_SB_MAGIC;
896 	sb->major_version = mddev->major_version;
897 	sb->patch_version = mddev->patch_version;
898 	sb->gvalid_words  = 0; /* ignored */
899 	memcpy(&sb->set_uuid0, mddev->uuid+0, 4);
900 	memcpy(&sb->set_uuid1, mddev->uuid+4, 4);
901 	memcpy(&sb->set_uuid2, mddev->uuid+8, 4);
902 	memcpy(&sb->set_uuid3, mddev->uuid+12,4);
903 
904 	sb->ctime = mddev->ctime;
905 	sb->level = mddev->level;
906 	sb->size  = mddev->size;
907 	sb->raid_disks = mddev->raid_disks;
908 	sb->md_minor = mddev->md_minor;
909 	sb->not_persistent = 0;
910 	sb->utime = mddev->utime;
911 	sb->state = 0;
912 	sb->events_hi = (mddev->events>>32);
913 	sb->events_lo = (u32)mddev->events;
914 
915 	if (mddev->reshape_position == MaxSector)
916 		sb->minor_version = 90;
917 	else {
918 		sb->minor_version = 91;
919 		sb->reshape_position = mddev->reshape_position;
920 		sb->new_level = mddev->new_level;
921 		sb->delta_disks = mddev->delta_disks;
922 		sb->new_layout = mddev->new_layout;
923 		sb->new_chunk = mddev->new_chunk;
924 	}
925 	mddev->minor_version = sb->minor_version;
926 	if (mddev->in_sync)
927 	{
928 		sb->recovery_cp = mddev->recovery_cp;
929 		sb->cp_events_hi = (mddev->events>>32);
930 		sb->cp_events_lo = (u32)mddev->events;
931 		if (mddev->recovery_cp == MaxSector)
932 			sb->state = (1<< MD_SB_CLEAN);
933 	} else
934 		sb->recovery_cp = 0;
935 
936 	sb->layout = mddev->layout;
937 	sb->chunk_size = mddev->chunk_size;
938 
939 	if (mddev->bitmap && mddev->bitmap_file == NULL)
940 		sb->state |= (1<<MD_SB_BITMAP_PRESENT);
941 
942 	sb->disks[0].state = (1<<MD_DISK_REMOVED);
943 	rdev_for_each(rdev2, tmp, mddev) {
944 		mdp_disk_t *d;
945 		int desc_nr;
946 		if (rdev2->raid_disk >= 0 && test_bit(In_sync, &rdev2->flags)
947 		    && !test_bit(Faulty, &rdev2->flags))
948 			desc_nr = rdev2->raid_disk;
949 		else
950 			desc_nr = next_spare++;
951 		rdev2->desc_nr = desc_nr;
952 		d = &sb->disks[rdev2->desc_nr];
953 		nr_disks++;
954 		d->number = rdev2->desc_nr;
955 		d->major = MAJOR(rdev2->bdev->bd_dev);
956 		d->minor = MINOR(rdev2->bdev->bd_dev);
957 		if (rdev2->raid_disk >= 0 && test_bit(In_sync, &rdev2->flags)
958 		    && !test_bit(Faulty, &rdev2->flags))
959 			d->raid_disk = rdev2->raid_disk;
960 		else
961 			d->raid_disk = rdev2->desc_nr; /* compatibility */
962 		if (test_bit(Faulty, &rdev2->flags))
963 			d->state = (1<<MD_DISK_FAULTY);
964 		else if (test_bit(In_sync, &rdev2->flags)) {
965 			d->state = (1<<MD_DISK_ACTIVE);
966 			d->state |= (1<<MD_DISK_SYNC);
967 			active++;
968 			working++;
969 		} else {
970 			d->state = 0;
971 			spare++;
972 			working++;
973 		}
974 		if (test_bit(WriteMostly, &rdev2->flags))
975 			d->state |= (1<<MD_DISK_WRITEMOSTLY);
976 	}
977 	/* now set the "removed" and "faulty" bits on any missing devices */
978 	for (i=0 ; i < mddev->raid_disks ; i++) {
979 		mdp_disk_t *d = &sb->disks[i];
980 		if (d->state == 0 && d->number == 0) {
981 			d->number = i;
982 			d->raid_disk = i;
983 			d->state = (1<<MD_DISK_REMOVED);
984 			d->state |= (1<<MD_DISK_FAULTY);
985 			failed++;
986 		}
987 	}
988 	sb->nr_disks = nr_disks;
989 	sb->active_disks = active;
990 	sb->working_disks = working;
991 	sb->failed_disks = failed;
992 	sb->spare_disks = spare;
993 
994 	sb->this_disk = sb->disks[rdev->desc_nr];
995 	sb->sb_csum = calc_sb_csum(sb);
996 }
997 
998 /*
999  * rdev_size_change for 0.90.0
1000  */
1001 static unsigned long long
1002 super_90_rdev_size_change(mdk_rdev_t *rdev, sector_t num_sectors)
1003 {
1004 	if (num_sectors && num_sectors < rdev->mddev->size * 2)
1005 		return 0; /* component must fit device */
1006 	if (rdev->mddev->bitmap_offset)
1007 		return 0; /* can't move bitmap */
1008 	rdev->sb_start = calc_dev_sboffset(rdev->bdev);
1009 	if (!num_sectors || num_sectors > rdev->sb_start)
1010 		num_sectors = rdev->sb_start;
1011 	md_super_write(rdev->mddev, rdev, rdev->sb_start, rdev->sb_size,
1012 		       rdev->sb_page);
1013 	md_super_wait(rdev->mddev);
1014 	return num_sectors / 2; /* kB for sysfs */
1015 }
1016 
1017 
1018 /*
1019  * version 1 superblock
1020  */
1021 
1022 static __le32 calc_sb_1_csum(struct mdp_superblock_1 * sb)
1023 {
1024 	__le32 disk_csum;
1025 	u32 csum;
1026 	unsigned long long newcsum;
1027 	int size = 256 + le32_to_cpu(sb->max_dev)*2;
1028 	__le32 *isuper = (__le32*)sb;
1029 	int i;
1030 
1031 	disk_csum = sb->sb_csum;
1032 	sb->sb_csum = 0;
1033 	newcsum = 0;
1034 	for (i=0; size>=4; size -= 4 )
1035 		newcsum += le32_to_cpu(*isuper++);
1036 
1037 	if (size == 2)
1038 		newcsum += le16_to_cpu(*(__le16*) isuper);
1039 
1040 	csum = (newcsum & 0xffffffff) + (newcsum >> 32);
1041 	sb->sb_csum = disk_csum;
1042 	return cpu_to_le32(csum);
1043 }
1044 
1045 static int super_1_load(mdk_rdev_t *rdev, mdk_rdev_t *refdev, int minor_version)
1046 {
1047 	struct mdp_superblock_1 *sb;
1048 	int ret;
1049 	sector_t sb_start;
1050 	char b[BDEVNAME_SIZE], b2[BDEVNAME_SIZE];
1051 	int bmask;
1052 
1053 	/*
1054 	 * Calculate the position of the superblock in 512byte sectors.
1055 	 * It is always aligned to a 4K boundary and
1056 	 * depeding on minor_version, it can be:
1057 	 * 0: At least 8K, but less than 12K, from end of device
1058 	 * 1: At start of device
1059 	 * 2: 4K from start of device.
1060 	 */
1061 	switch(minor_version) {
1062 	case 0:
1063 		sb_start = rdev->bdev->bd_inode->i_size >> 9;
1064 		sb_start -= 8*2;
1065 		sb_start &= ~(sector_t)(4*2-1);
1066 		break;
1067 	case 1:
1068 		sb_start = 0;
1069 		break;
1070 	case 2:
1071 		sb_start = 8;
1072 		break;
1073 	default:
1074 		return -EINVAL;
1075 	}
1076 	rdev->sb_start = sb_start;
1077 
1078 	/* superblock is rarely larger than 1K, but it can be larger,
1079 	 * and it is safe to read 4k, so we do that
1080 	 */
1081 	ret = read_disk_sb(rdev, 4096);
1082 	if (ret) return ret;
1083 
1084 
1085 	sb = (struct mdp_superblock_1*)page_address(rdev->sb_page);
1086 
1087 	if (sb->magic != cpu_to_le32(MD_SB_MAGIC) ||
1088 	    sb->major_version != cpu_to_le32(1) ||
1089 	    le32_to_cpu(sb->max_dev) > (4096-256)/2 ||
1090 	    le64_to_cpu(sb->super_offset) != rdev->sb_start ||
1091 	    (le32_to_cpu(sb->feature_map) & ~MD_FEATURE_ALL) != 0)
1092 		return -EINVAL;
1093 
1094 	if (calc_sb_1_csum(sb) != sb->sb_csum) {
1095 		printk("md: invalid superblock checksum on %s\n",
1096 			bdevname(rdev->bdev,b));
1097 		return -EINVAL;
1098 	}
1099 	if (le64_to_cpu(sb->data_size) < 10) {
1100 		printk("md: data_size too small on %s\n",
1101 		       bdevname(rdev->bdev,b));
1102 		return -EINVAL;
1103 	}
1104 	if ((le32_to_cpu(sb->feature_map) & MD_FEATURE_BITMAP_OFFSET)) {
1105 		if (sb->level != cpu_to_le32(1) &&
1106 		    sb->level != cpu_to_le32(4) &&
1107 		    sb->level != cpu_to_le32(5) &&
1108 		    sb->level != cpu_to_le32(6) &&
1109 		    sb->level != cpu_to_le32(10)) {
1110 			printk(KERN_WARNING
1111 			       "md: bitmaps not supported for this level.\n");
1112 			return -EINVAL;
1113 		}
1114 	}
1115 
1116 	rdev->preferred_minor = 0xffff;
1117 	rdev->data_offset = le64_to_cpu(sb->data_offset);
1118 	atomic_set(&rdev->corrected_errors, le32_to_cpu(sb->cnt_corrected_read));
1119 
1120 	rdev->sb_size = le32_to_cpu(sb->max_dev) * 2 + 256;
1121 	bmask = queue_hardsect_size(rdev->bdev->bd_disk->queue)-1;
1122 	if (rdev->sb_size & bmask)
1123 		rdev->sb_size = (rdev->sb_size | bmask) + 1;
1124 
1125 	if (minor_version
1126 	    && rdev->data_offset < sb_start + (rdev->sb_size/512))
1127 		return -EINVAL;
1128 
1129 	if (sb->level == cpu_to_le32(LEVEL_MULTIPATH))
1130 		rdev->desc_nr = -1;
1131 	else
1132 		rdev->desc_nr = le32_to_cpu(sb->dev_number);
1133 
1134 	if (!refdev) {
1135 		ret = 1;
1136 	} else {
1137 		__u64 ev1, ev2;
1138 		struct mdp_superblock_1 *refsb =
1139 			(struct mdp_superblock_1*)page_address(refdev->sb_page);
1140 
1141 		if (memcmp(sb->set_uuid, refsb->set_uuid, 16) != 0 ||
1142 		    sb->level != refsb->level ||
1143 		    sb->layout != refsb->layout ||
1144 		    sb->chunksize != refsb->chunksize) {
1145 			printk(KERN_WARNING "md: %s has strangely different"
1146 				" superblock to %s\n",
1147 				bdevname(rdev->bdev,b),
1148 				bdevname(refdev->bdev,b2));
1149 			return -EINVAL;
1150 		}
1151 		ev1 = le64_to_cpu(sb->events);
1152 		ev2 = le64_to_cpu(refsb->events);
1153 
1154 		if (ev1 > ev2)
1155 			ret = 1;
1156 		else
1157 			ret = 0;
1158 	}
1159 	if (minor_version)
1160 		rdev->size = ((rdev->bdev->bd_inode->i_size>>9) - le64_to_cpu(sb->data_offset)) / 2;
1161 	else
1162 		rdev->size = rdev->sb_start / 2;
1163 	if (rdev->size < le64_to_cpu(sb->data_size)/2)
1164 		return -EINVAL;
1165 	rdev->size = le64_to_cpu(sb->data_size)/2;
1166 	if (le32_to_cpu(sb->chunksize))
1167 		rdev->size &= ~((sector_t)le32_to_cpu(sb->chunksize)/2 - 1);
1168 
1169 	if (le64_to_cpu(sb->size) > rdev->size*2)
1170 		return -EINVAL;
1171 	return ret;
1172 }
1173 
1174 static int super_1_validate(mddev_t *mddev, mdk_rdev_t *rdev)
1175 {
1176 	struct mdp_superblock_1 *sb = (struct mdp_superblock_1*)page_address(rdev->sb_page);
1177 	__u64 ev1 = le64_to_cpu(sb->events);
1178 
1179 	rdev->raid_disk = -1;
1180 	clear_bit(Faulty, &rdev->flags);
1181 	clear_bit(In_sync, &rdev->flags);
1182 	clear_bit(WriteMostly, &rdev->flags);
1183 	clear_bit(BarriersNotsupp, &rdev->flags);
1184 
1185 	if (mddev->raid_disks == 0) {
1186 		mddev->major_version = 1;
1187 		mddev->patch_version = 0;
1188 		mddev->external = 0;
1189 		mddev->chunk_size = le32_to_cpu(sb->chunksize) << 9;
1190 		mddev->ctime = le64_to_cpu(sb->ctime) & ((1ULL << 32)-1);
1191 		mddev->utime = le64_to_cpu(sb->utime) & ((1ULL << 32)-1);
1192 		mddev->level = le32_to_cpu(sb->level);
1193 		mddev->clevel[0] = 0;
1194 		mddev->layout = le32_to_cpu(sb->layout);
1195 		mddev->raid_disks = le32_to_cpu(sb->raid_disks);
1196 		mddev->size = le64_to_cpu(sb->size)/2;
1197 		mddev->events = ev1;
1198 		mddev->bitmap_offset = 0;
1199 		mddev->default_bitmap_offset = 1024 >> 9;
1200 
1201 		mddev->recovery_cp = le64_to_cpu(sb->resync_offset);
1202 		memcpy(mddev->uuid, sb->set_uuid, 16);
1203 
1204 		mddev->max_disks =  (4096-256)/2;
1205 
1206 		if ((le32_to_cpu(sb->feature_map) & MD_FEATURE_BITMAP_OFFSET) &&
1207 		    mddev->bitmap_file == NULL )
1208 			mddev->bitmap_offset = (__s32)le32_to_cpu(sb->bitmap_offset);
1209 
1210 		if ((le32_to_cpu(sb->feature_map) & MD_FEATURE_RESHAPE_ACTIVE)) {
1211 			mddev->reshape_position = le64_to_cpu(sb->reshape_position);
1212 			mddev->delta_disks = le32_to_cpu(sb->delta_disks);
1213 			mddev->new_level = le32_to_cpu(sb->new_level);
1214 			mddev->new_layout = le32_to_cpu(sb->new_layout);
1215 			mddev->new_chunk = le32_to_cpu(sb->new_chunk)<<9;
1216 		} else {
1217 			mddev->reshape_position = MaxSector;
1218 			mddev->delta_disks = 0;
1219 			mddev->new_level = mddev->level;
1220 			mddev->new_layout = mddev->layout;
1221 			mddev->new_chunk = mddev->chunk_size;
1222 		}
1223 
1224 	} else if (mddev->pers == NULL) {
1225 		/* Insist of good event counter while assembling */
1226 		++ev1;
1227 		if (ev1 < mddev->events)
1228 			return -EINVAL;
1229 	} else if (mddev->bitmap) {
1230 		/* If adding to array with a bitmap, then we can accept an
1231 		 * older device, but not too old.
1232 		 */
1233 		if (ev1 < mddev->bitmap->events_cleared)
1234 			return 0;
1235 	} else {
1236 		if (ev1 < mddev->events)
1237 			/* just a hot-add of a new device, leave raid_disk at -1 */
1238 			return 0;
1239 	}
1240 	if (mddev->level != LEVEL_MULTIPATH) {
1241 		int role;
1242 		role = le16_to_cpu(sb->dev_roles[rdev->desc_nr]);
1243 		switch(role) {
1244 		case 0xffff: /* spare */
1245 			break;
1246 		case 0xfffe: /* faulty */
1247 			set_bit(Faulty, &rdev->flags);
1248 			break;
1249 		default:
1250 			if ((le32_to_cpu(sb->feature_map) &
1251 			     MD_FEATURE_RECOVERY_OFFSET))
1252 				rdev->recovery_offset = le64_to_cpu(sb->recovery_offset);
1253 			else
1254 				set_bit(In_sync, &rdev->flags);
1255 			rdev->raid_disk = role;
1256 			break;
1257 		}
1258 		if (sb->devflags & WriteMostly1)
1259 			set_bit(WriteMostly, &rdev->flags);
1260 	} else /* MULTIPATH are always insync */
1261 		set_bit(In_sync, &rdev->flags);
1262 
1263 	return 0;
1264 }
1265 
1266 static void super_1_sync(mddev_t *mddev, mdk_rdev_t *rdev)
1267 {
1268 	struct mdp_superblock_1 *sb;
1269 	struct list_head *tmp;
1270 	mdk_rdev_t *rdev2;
1271 	int max_dev, i;
1272 	/* make rdev->sb match mddev and rdev data. */
1273 
1274 	sb = (struct mdp_superblock_1*)page_address(rdev->sb_page);
1275 
1276 	sb->feature_map = 0;
1277 	sb->pad0 = 0;
1278 	sb->recovery_offset = cpu_to_le64(0);
1279 	memset(sb->pad1, 0, sizeof(sb->pad1));
1280 	memset(sb->pad2, 0, sizeof(sb->pad2));
1281 	memset(sb->pad3, 0, sizeof(sb->pad3));
1282 
1283 	sb->utime = cpu_to_le64((__u64)mddev->utime);
1284 	sb->events = cpu_to_le64(mddev->events);
1285 	if (mddev->in_sync)
1286 		sb->resync_offset = cpu_to_le64(mddev->recovery_cp);
1287 	else
1288 		sb->resync_offset = cpu_to_le64(0);
1289 
1290 	sb->cnt_corrected_read = cpu_to_le32(atomic_read(&rdev->corrected_errors));
1291 
1292 	sb->raid_disks = cpu_to_le32(mddev->raid_disks);
1293 	sb->size = cpu_to_le64(mddev->size<<1);
1294 
1295 	if (mddev->bitmap && mddev->bitmap_file == NULL) {
1296 		sb->bitmap_offset = cpu_to_le32((__u32)mddev->bitmap_offset);
1297 		sb->feature_map = cpu_to_le32(MD_FEATURE_BITMAP_OFFSET);
1298 	}
1299 
1300 	if (rdev->raid_disk >= 0 &&
1301 	    !test_bit(In_sync, &rdev->flags) &&
1302 	    rdev->recovery_offset > 0) {
1303 		sb->feature_map |= cpu_to_le32(MD_FEATURE_RECOVERY_OFFSET);
1304 		sb->recovery_offset = cpu_to_le64(rdev->recovery_offset);
1305 	}
1306 
1307 	if (mddev->reshape_position != MaxSector) {
1308 		sb->feature_map |= cpu_to_le32(MD_FEATURE_RESHAPE_ACTIVE);
1309 		sb->reshape_position = cpu_to_le64(mddev->reshape_position);
1310 		sb->new_layout = cpu_to_le32(mddev->new_layout);
1311 		sb->delta_disks = cpu_to_le32(mddev->delta_disks);
1312 		sb->new_level = cpu_to_le32(mddev->new_level);
1313 		sb->new_chunk = cpu_to_le32(mddev->new_chunk>>9);
1314 	}
1315 
1316 	max_dev = 0;
1317 	rdev_for_each(rdev2, tmp, mddev)
1318 		if (rdev2->desc_nr+1 > max_dev)
1319 			max_dev = rdev2->desc_nr+1;
1320 
1321 	if (max_dev > le32_to_cpu(sb->max_dev))
1322 		sb->max_dev = cpu_to_le32(max_dev);
1323 	for (i=0; i<max_dev;i++)
1324 		sb->dev_roles[i] = cpu_to_le16(0xfffe);
1325 
1326 	rdev_for_each(rdev2, tmp, mddev) {
1327 		i = rdev2->desc_nr;
1328 		if (test_bit(Faulty, &rdev2->flags))
1329 			sb->dev_roles[i] = cpu_to_le16(0xfffe);
1330 		else if (test_bit(In_sync, &rdev2->flags))
1331 			sb->dev_roles[i] = cpu_to_le16(rdev2->raid_disk);
1332 		else if (rdev2->raid_disk >= 0 && rdev2->recovery_offset > 0)
1333 			sb->dev_roles[i] = cpu_to_le16(rdev2->raid_disk);
1334 		else
1335 			sb->dev_roles[i] = cpu_to_le16(0xffff);
1336 	}
1337 
1338 	sb->sb_csum = calc_sb_1_csum(sb);
1339 }
1340 
1341 static unsigned long long
1342 super_1_rdev_size_change(mdk_rdev_t *rdev, sector_t num_sectors)
1343 {
1344 	struct mdp_superblock_1 *sb;
1345 	sector_t max_sectors;
1346 	if (num_sectors && num_sectors < rdev->mddev->size * 2)
1347 		return 0; /* component must fit device */
1348 	if (rdev->sb_start < rdev->data_offset) {
1349 		/* minor versions 1 and 2; superblock before data */
1350 		max_sectors = rdev->bdev->bd_inode->i_size >> 9;
1351 		max_sectors -= rdev->data_offset;
1352 		if (!num_sectors || num_sectors > max_sectors)
1353 			num_sectors = max_sectors;
1354 	} else if (rdev->mddev->bitmap_offset) {
1355 		/* minor version 0 with bitmap we can't move */
1356 		return 0;
1357 	} else {
1358 		/* minor version 0; superblock after data */
1359 		sector_t sb_start;
1360 		sb_start = (rdev->bdev->bd_inode->i_size >> 9) - 8*2;
1361 		sb_start &= ~(sector_t)(4*2 - 1);
1362 		max_sectors = rdev->size * 2 + sb_start - rdev->sb_start;
1363 		if (!num_sectors || num_sectors > max_sectors)
1364 			num_sectors = max_sectors;
1365 		rdev->sb_start = sb_start;
1366 	}
1367 	sb = (struct mdp_superblock_1 *) page_address(rdev->sb_page);
1368 	sb->data_size = cpu_to_le64(num_sectors);
1369 	sb->super_offset = rdev->sb_start;
1370 	sb->sb_csum = calc_sb_1_csum(sb);
1371 	md_super_write(rdev->mddev, rdev, rdev->sb_start, rdev->sb_size,
1372 		       rdev->sb_page);
1373 	md_super_wait(rdev->mddev);
1374 	return num_sectors / 2; /* kB for sysfs */
1375 }
1376 
1377 static struct super_type super_types[] = {
1378 	[0] = {
1379 		.name	= "0.90.0",
1380 		.owner	= THIS_MODULE,
1381 		.load_super	    = super_90_load,
1382 		.validate_super	    = super_90_validate,
1383 		.sync_super	    = super_90_sync,
1384 		.rdev_size_change   = super_90_rdev_size_change,
1385 	},
1386 	[1] = {
1387 		.name	= "md-1",
1388 		.owner	= THIS_MODULE,
1389 		.load_super	    = super_1_load,
1390 		.validate_super	    = super_1_validate,
1391 		.sync_super	    = super_1_sync,
1392 		.rdev_size_change   = super_1_rdev_size_change,
1393 	},
1394 };
1395 
1396 static int match_mddev_units(mddev_t *mddev1, mddev_t *mddev2)
1397 {
1398 	mdk_rdev_t *rdev, *rdev2;
1399 
1400 	rcu_read_lock();
1401 	rdev_for_each_rcu(rdev, mddev1)
1402 		rdev_for_each_rcu(rdev2, mddev2)
1403 			if (rdev->bdev->bd_contains ==
1404 			    rdev2->bdev->bd_contains) {
1405 				rcu_read_unlock();
1406 				return 1;
1407 			}
1408 	rcu_read_unlock();
1409 	return 0;
1410 }
1411 
1412 static LIST_HEAD(pending_raid_disks);
1413 
1414 static int bind_rdev_to_array(mdk_rdev_t * rdev, mddev_t * mddev)
1415 {
1416 	char b[BDEVNAME_SIZE];
1417 	struct kobject *ko;
1418 	char *s;
1419 	int err;
1420 
1421 	if (rdev->mddev) {
1422 		MD_BUG();
1423 		return -EINVAL;
1424 	}
1425 
1426 	/* prevent duplicates */
1427 	if (find_rdev(mddev, rdev->bdev->bd_dev))
1428 		return -EEXIST;
1429 
1430 	/* make sure rdev->size exceeds mddev->size */
1431 	if (rdev->size && (mddev->size == 0 || rdev->size < mddev->size)) {
1432 		if (mddev->pers) {
1433 			/* Cannot change size, so fail
1434 			 * If mddev->level <= 0, then we don't care
1435 			 * about aligning sizes (e.g. linear)
1436 			 */
1437 			if (mddev->level > 0)
1438 				return -ENOSPC;
1439 		} else
1440 			mddev->size = rdev->size;
1441 	}
1442 
1443 	/* Verify rdev->desc_nr is unique.
1444 	 * If it is -1, assign a free number, else
1445 	 * check number is not in use
1446 	 */
1447 	if (rdev->desc_nr < 0) {
1448 		int choice = 0;
1449 		if (mddev->pers) choice = mddev->raid_disks;
1450 		while (find_rdev_nr(mddev, choice))
1451 			choice++;
1452 		rdev->desc_nr = choice;
1453 	} else {
1454 		if (find_rdev_nr(mddev, rdev->desc_nr))
1455 			return -EBUSY;
1456 	}
1457 	bdevname(rdev->bdev,b);
1458 	while ( (s=strchr(b, '/')) != NULL)
1459 		*s = '!';
1460 
1461 	rdev->mddev = mddev;
1462 	printk(KERN_INFO "md: bind<%s>\n", b);
1463 
1464 	if ((err = kobject_add(&rdev->kobj, &mddev->kobj, "dev-%s", b)))
1465 		goto fail;
1466 
1467 	if (rdev->bdev->bd_part)
1468 		ko = &rdev->bdev->bd_part->dev.kobj;
1469 	else
1470 		ko = &rdev->bdev->bd_disk->dev.kobj;
1471 	if ((err = sysfs_create_link(&rdev->kobj, ko, "block"))) {
1472 		kobject_del(&rdev->kobj);
1473 		goto fail;
1474 	}
1475 	list_add_rcu(&rdev->same_set, &mddev->disks);
1476 	bd_claim_by_disk(rdev->bdev, rdev->bdev->bd_holder, mddev->gendisk);
1477 	return 0;
1478 
1479  fail:
1480 	printk(KERN_WARNING "md: failed to register dev-%s for %s\n",
1481 	       b, mdname(mddev));
1482 	return err;
1483 }
1484 
1485 static void md_delayed_delete(struct work_struct *ws)
1486 {
1487 	mdk_rdev_t *rdev = container_of(ws, mdk_rdev_t, del_work);
1488 	kobject_del(&rdev->kobj);
1489 	kobject_put(&rdev->kobj);
1490 }
1491 
1492 static void unbind_rdev_from_array(mdk_rdev_t * rdev)
1493 {
1494 	char b[BDEVNAME_SIZE];
1495 	if (!rdev->mddev) {
1496 		MD_BUG();
1497 		return;
1498 	}
1499 	bd_release_from_disk(rdev->bdev, rdev->mddev->gendisk);
1500 	list_del_rcu(&rdev->same_set);
1501 	printk(KERN_INFO "md: unbind<%s>\n", bdevname(rdev->bdev,b));
1502 	rdev->mddev = NULL;
1503 	sysfs_remove_link(&rdev->kobj, "block");
1504 
1505 	/* We need to delay this, otherwise we can deadlock when
1506 	 * writing to 'remove' to "dev/state".  We also need
1507 	 * to delay it due to rcu usage.
1508 	 */
1509 	synchronize_rcu();
1510 	INIT_WORK(&rdev->del_work, md_delayed_delete);
1511 	kobject_get(&rdev->kobj);
1512 	schedule_work(&rdev->del_work);
1513 }
1514 
1515 /*
1516  * prevent the device from being mounted, repartitioned or
1517  * otherwise reused by a RAID array (or any other kernel
1518  * subsystem), by bd_claiming the device.
1519  */
1520 static int lock_rdev(mdk_rdev_t *rdev, dev_t dev, int shared)
1521 {
1522 	int err = 0;
1523 	struct block_device *bdev;
1524 	char b[BDEVNAME_SIZE];
1525 
1526 	bdev = open_by_devnum(dev, FMODE_READ|FMODE_WRITE);
1527 	if (IS_ERR(bdev)) {
1528 		printk(KERN_ERR "md: could not open %s.\n",
1529 			__bdevname(dev, b));
1530 		return PTR_ERR(bdev);
1531 	}
1532 	err = bd_claim(bdev, shared ? (mdk_rdev_t *)lock_rdev : rdev);
1533 	if (err) {
1534 		printk(KERN_ERR "md: could not bd_claim %s.\n",
1535 			bdevname(bdev, b));
1536 		blkdev_put(bdev);
1537 		return err;
1538 	}
1539 	if (!shared)
1540 		set_bit(AllReserved, &rdev->flags);
1541 	rdev->bdev = bdev;
1542 	return err;
1543 }
1544 
1545 static void unlock_rdev(mdk_rdev_t *rdev)
1546 {
1547 	struct block_device *bdev = rdev->bdev;
1548 	rdev->bdev = NULL;
1549 	if (!bdev)
1550 		MD_BUG();
1551 	bd_release(bdev);
1552 	blkdev_put(bdev);
1553 }
1554 
1555 void md_autodetect_dev(dev_t dev);
1556 
1557 static void export_rdev(mdk_rdev_t * rdev)
1558 {
1559 	char b[BDEVNAME_SIZE];
1560 	printk(KERN_INFO "md: export_rdev(%s)\n",
1561 		bdevname(rdev->bdev,b));
1562 	if (rdev->mddev)
1563 		MD_BUG();
1564 	free_disk_sb(rdev);
1565 #ifndef MODULE
1566 	if (test_bit(AutoDetected, &rdev->flags))
1567 		md_autodetect_dev(rdev->bdev->bd_dev);
1568 #endif
1569 	unlock_rdev(rdev);
1570 	kobject_put(&rdev->kobj);
1571 }
1572 
1573 static void kick_rdev_from_array(mdk_rdev_t * rdev)
1574 {
1575 	unbind_rdev_from_array(rdev);
1576 	export_rdev(rdev);
1577 }
1578 
1579 static void export_array(mddev_t *mddev)
1580 {
1581 	struct list_head *tmp;
1582 	mdk_rdev_t *rdev;
1583 
1584 	rdev_for_each(rdev, tmp, mddev) {
1585 		if (!rdev->mddev) {
1586 			MD_BUG();
1587 			continue;
1588 		}
1589 		kick_rdev_from_array(rdev);
1590 	}
1591 	if (!list_empty(&mddev->disks))
1592 		MD_BUG();
1593 	mddev->raid_disks = 0;
1594 	mddev->major_version = 0;
1595 }
1596 
1597 static void print_desc(mdp_disk_t *desc)
1598 {
1599 	printk(" DISK<N:%d,(%d,%d),R:%d,S:%d>\n", desc->number,
1600 		desc->major,desc->minor,desc->raid_disk,desc->state);
1601 }
1602 
1603 static void print_sb(mdp_super_t *sb)
1604 {
1605 	int i;
1606 
1607 	printk(KERN_INFO
1608 		"md:  SB: (V:%d.%d.%d) ID:<%08x.%08x.%08x.%08x> CT:%08x\n",
1609 		sb->major_version, sb->minor_version, sb->patch_version,
1610 		sb->set_uuid0, sb->set_uuid1, sb->set_uuid2, sb->set_uuid3,
1611 		sb->ctime);
1612 	printk(KERN_INFO "md:     L%d S%08d ND:%d RD:%d md%d LO:%d CS:%d\n",
1613 		sb->level, sb->size, sb->nr_disks, sb->raid_disks,
1614 		sb->md_minor, sb->layout, sb->chunk_size);
1615 	printk(KERN_INFO "md:     UT:%08x ST:%d AD:%d WD:%d"
1616 		" FD:%d SD:%d CSUM:%08x E:%08lx\n",
1617 		sb->utime, sb->state, sb->active_disks, sb->working_disks,
1618 		sb->failed_disks, sb->spare_disks,
1619 		sb->sb_csum, (unsigned long)sb->events_lo);
1620 
1621 	printk(KERN_INFO);
1622 	for (i = 0; i < MD_SB_DISKS; i++) {
1623 		mdp_disk_t *desc;
1624 
1625 		desc = sb->disks + i;
1626 		if (desc->number || desc->major || desc->minor ||
1627 		    desc->raid_disk || (desc->state && (desc->state != 4))) {
1628 			printk("     D %2d: ", i);
1629 			print_desc(desc);
1630 		}
1631 	}
1632 	printk(KERN_INFO "md:     THIS: ");
1633 	print_desc(&sb->this_disk);
1634 
1635 }
1636 
1637 static void print_rdev(mdk_rdev_t *rdev)
1638 {
1639 	char b[BDEVNAME_SIZE];
1640 	printk(KERN_INFO "md: rdev %s, SZ:%08llu F:%d S:%d DN:%u\n",
1641 		bdevname(rdev->bdev,b), (unsigned long long)rdev->size,
1642 	        test_bit(Faulty, &rdev->flags), test_bit(In_sync, &rdev->flags),
1643 	        rdev->desc_nr);
1644 	if (rdev->sb_loaded) {
1645 		printk(KERN_INFO "md: rdev superblock:\n");
1646 		print_sb((mdp_super_t*)page_address(rdev->sb_page));
1647 	} else
1648 		printk(KERN_INFO "md: no rdev superblock!\n");
1649 }
1650 
1651 static void md_print_devices(void)
1652 {
1653 	struct list_head *tmp, *tmp2;
1654 	mdk_rdev_t *rdev;
1655 	mddev_t *mddev;
1656 	char b[BDEVNAME_SIZE];
1657 
1658 	printk("\n");
1659 	printk("md:	**********************************\n");
1660 	printk("md:	* <COMPLETE RAID STATE PRINTOUT> *\n");
1661 	printk("md:	**********************************\n");
1662 	for_each_mddev(mddev, tmp) {
1663 
1664 		if (mddev->bitmap)
1665 			bitmap_print_sb(mddev->bitmap);
1666 		else
1667 			printk("%s: ", mdname(mddev));
1668 		rdev_for_each(rdev, tmp2, mddev)
1669 			printk("<%s>", bdevname(rdev->bdev,b));
1670 		printk("\n");
1671 
1672 		rdev_for_each(rdev, tmp2, mddev)
1673 			print_rdev(rdev);
1674 	}
1675 	printk("md:	**********************************\n");
1676 	printk("\n");
1677 }
1678 
1679 
1680 static void sync_sbs(mddev_t * mddev, int nospares)
1681 {
1682 	/* Update each superblock (in-memory image), but
1683 	 * if we are allowed to, skip spares which already
1684 	 * have the right event counter, or have one earlier
1685 	 * (which would mean they aren't being marked as dirty
1686 	 * with the rest of the array)
1687 	 */
1688 	mdk_rdev_t *rdev;
1689 	struct list_head *tmp;
1690 
1691 	rdev_for_each(rdev, tmp, mddev) {
1692 		if (rdev->sb_events == mddev->events ||
1693 		    (nospares &&
1694 		     rdev->raid_disk < 0 &&
1695 		     (rdev->sb_events&1)==0 &&
1696 		     rdev->sb_events+1 == mddev->events)) {
1697 			/* Don't update this superblock */
1698 			rdev->sb_loaded = 2;
1699 		} else {
1700 			super_types[mddev->major_version].
1701 				sync_super(mddev, rdev);
1702 			rdev->sb_loaded = 1;
1703 		}
1704 	}
1705 }
1706 
1707 static void md_update_sb(mddev_t * mddev, int force_change)
1708 {
1709 	struct list_head *tmp;
1710 	mdk_rdev_t *rdev;
1711 	int sync_req;
1712 	int nospares = 0;
1713 
1714 	if (mddev->external)
1715 		return;
1716 repeat:
1717 	spin_lock_irq(&mddev->write_lock);
1718 
1719 	set_bit(MD_CHANGE_PENDING, &mddev->flags);
1720 	if (test_and_clear_bit(MD_CHANGE_DEVS, &mddev->flags))
1721 		force_change = 1;
1722 	if (test_and_clear_bit(MD_CHANGE_CLEAN, &mddev->flags))
1723 		/* just a clean<-> dirty transition, possibly leave spares alone,
1724 		 * though if events isn't the right even/odd, we will have to do
1725 		 * spares after all
1726 		 */
1727 		nospares = 1;
1728 	if (force_change)
1729 		nospares = 0;
1730 	if (mddev->degraded)
1731 		/* If the array is degraded, then skipping spares is both
1732 		 * dangerous and fairly pointless.
1733 		 * Dangerous because a device that was removed from the array
1734 		 * might have a event_count that still looks up-to-date,
1735 		 * so it can be re-added without a resync.
1736 		 * Pointless because if there are any spares to skip,
1737 		 * then a recovery will happen and soon that array won't
1738 		 * be degraded any more and the spare can go back to sleep then.
1739 		 */
1740 		nospares = 0;
1741 
1742 	sync_req = mddev->in_sync;
1743 	mddev->utime = get_seconds();
1744 
1745 	/* If this is just a dirty<->clean transition, and the array is clean
1746 	 * and 'events' is odd, we can roll back to the previous clean state */
1747 	if (nospares
1748 	    && (mddev->in_sync && mddev->recovery_cp == MaxSector)
1749 	    && (mddev->events & 1)
1750 	    && mddev->events != 1)
1751 		mddev->events--;
1752 	else {
1753 		/* otherwise we have to go forward and ... */
1754 		mddev->events ++;
1755 		if (!mddev->in_sync || mddev->recovery_cp != MaxSector) { /* not clean */
1756 			/* .. if the array isn't clean, insist on an odd 'events' */
1757 			if ((mddev->events&1)==0) {
1758 				mddev->events++;
1759 				nospares = 0;
1760 			}
1761 		} else {
1762 			/* otherwise insist on an even 'events' (for clean states) */
1763 			if ((mddev->events&1)) {
1764 				mddev->events++;
1765 				nospares = 0;
1766 			}
1767 		}
1768 	}
1769 
1770 	if (!mddev->events) {
1771 		/*
1772 		 * oops, this 64-bit counter should never wrap.
1773 		 * Either we are in around ~1 trillion A.C., assuming
1774 		 * 1 reboot per second, or we have a bug:
1775 		 */
1776 		MD_BUG();
1777 		mddev->events --;
1778 	}
1779 
1780 	/*
1781 	 * do not write anything to disk if using
1782 	 * nonpersistent superblocks
1783 	 */
1784 	if (!mddev->persistent) {
1785 		if (!mddev->external)
1786 			clear_bit(MD_CHANGE_PENDING, &mddev->flags);
1787 
1788 		spin_unlock_irq(&mddev->write_lock);
1789 		wake_up(&mddev->sb_wait);
1790 		return;
1791 	}
1792 	sync_sbs(mddev, nospares);
1793 	spin_unlock_irq(&mddev->write_lock);
1794 
1795 	dprintk(KERN_INFO
1796 		"md: updating %s RAID superblock on device (in sync %d)\n",
1797 		mdname(mddev),mddev->in_sync);
1798 
1799 	bitmap_update_sb(mddev->bitmap);
1800 	rdev_for_each(rdev, tmp, mddev) {
1801 		char b[BDEVNAME_SIZE];
1802 		dprintk(KERN_INFO "md: ");
1803 		if (rdev->sb_loaded != 1)
1804 			continue; /* no noise on spare devices */
1805 		if (test_bit(Faulty, &rdev->flags))
1806 			dprintk("(skipping faulty ");
1807 
1808 		dprintk("%s ", bdevname(rdev->bdev,b));
1809 		if (!test_bit(Faulty, &rdev->flags)) {
1810 			md_super_write(mddev,rdev,
1811 				       rdev->sb_start, rdev->sb_size,
1812 				       rdev->sb_page);
1813 			dprintk(KERN_INFO "(write) %s's sb offset: %llu\n",
1814 				bdevname(rdev->bdev,b),
1815 				(unsigned long long)rdev->sb_start);
1816 			rdev->sb_events = mddev->events;
1817 
1818 		} else
1819 			dprintk(")\n");
1820 		if (mddev->level == LEVEL_MULTIPATH)
1821 			/* only need to write one superblock... */
1822 			break;
1823 	}
1824 	md_super_wait(mddev);
1825 	/* if there was a failure, MD_CHANGE_DEVS was set, and we re-write super */
1826 
1827 	spin_lock_irq(&mddev->write_lock);
1828 	if (mddev->in_sync != sync_req ||
1829 	    test_bit(MD_CHANGE_DEVS, &mddev->flags)) {
1830 		/* have to write it out again */
1831 		spin_unlock_irq(&mddev->write_lock);
1832 		goto repeat;
1833 	}
1834 	clear_bit(MD_CHANGE_PENDING, &mddev->flags);
1835 	spin_unlock_irq(&mddev->write_lock);
1836 	wake_up(&mddev->sb_wait);
1837 
1838 }
1839 
1840 /* words written to sysfs files may, or may not, be \n terminated.
1841  * We want to accept with case. For this we use cmd_match.
1842  */
1843 static int cmd_match(const char *cmd, const char *str)
1844 {
1845 	/* See if cmd, written into a sysfs file, matches
1846 	 * str.  They must either be the same, or cmd can
1847 	 * have a trailing newline
1848 	 */
1849 	while (*cmd && *str && *cmd == *str) {
1850 		cmd++;
1851 		str++;
1852 	}
1853 	if (*cmd == '\n')
1854 		cmd++;
1855 	if (*str || *cmd)
1856 		return 0;
1857 	return 1;
1858 }
1859 
1860 struct rdev_sysfs_entry {
1861 	struct attribute attr;
1862 	ssize_t (*show)(mdk_rdev_t *, char *);
1863 	ssize_t (*store)(mdk_rdev_t *, const char *, size_t);
1864 };
1865 
1866 static ssize_t
1867 state_show(mdk_rdev_t *rdev, char *page)
1868 {
1869 	char *sep = "";
1870 	size_t len = 0;
1871 
1872 	if (test_bit(Faulty, &rdev->flags)) {
1873 		len+= sprintf(page+len, "%sfaulty",sep);
1874 		sep = ",";
1875 	}
1876 	if (test_bit(In_sync, &rdev->flags)) {
1877 		len += sprintf(page+len, "%sin_sync",sep);
1878 		sep = ",";
1879 	}
1880 	if (test_bit(WriteMostly, &rdev->flags)) {
1881 		len += sprintf(page+len, "%swrite_mostly",sep);
1882 		sep = ",";
1883 	}
1884 	if (test_bit(Blocked, &rdev->flags)) {
1885 		len += sprintf(page+len, "%sblocked", sep);
1886 		sep = ",";
1887 	}
1888 	if (!test_bit(Faulty, &rdev->flags) &&
1889 	    !test_bit(In_sync, &rdev->flags)) {
1890 		len += sprintf(page+len, "%sspare", sep);
1891 		sep = ",";
1892 	}
1893 	return len+sprintf(page+len, "\n");
1894 }
1895 
1896 static ssize_t
1897 state_store(mdk_rdev_t *rdev, const char *buf, size_t len)
1898 {
1899 	/* can write
1900 	 *  faulty  - simulates and error
1901 	 *  remove  - disconnects the device
1902 	 *  writemostly - sets write_mostly
1903 	 *  -writemostly - clears write_mostly
1904 	 *  blocked - sets the Blocked flag
1905 	 *  -blocked - clears the Blocked flag
1906 	 */
1907 	int err = -EINVAL;
1908 	if (cmd_match(buf, "faulty") && rdev->mddev->pers) {
1909 		md_error(rdev->mddev, rdev);
1910 		err = 0;
1911 	} else if (cmd_match(buf, "remove")) {
1912 		if (rdev->raid_disk >= 0)
1913 			err = -EBUSY;
1914 		else {
1915 			mddev_t *mddev = rdev->mddev;
1916 			kick_rdev_from_array(rdev);
1917 			if (mddev->pers)
1918 				md_update_sb(mddev, 1);
1919 			md_new_event(mddev);
1920 			err = 0;
1921 		}
1922 	} else if (cmd_match(buf, "writemostly")) {
1923 		set_bit(WriteMostly, &rdev->flags);
1924 		err = 0;
1925 	} else if (cmd_match(buf, "-writemostly")) {
1926 		clear_bit(WriteMostly, &rdev->flags);
1927 		err = 0;
1928 	} else if (cmd_match(buf, "blocked")) {
1929 		set_bit(Blocked, &rdev->flags);
1930 		err = 0;
1931 	} else if (cmd_match(buf, "-blocked")) {
1932 		clear_bit(Blocked, &rdev->flags);
1933 		wake_up(&rdev->blocked_wait);
1934 		set_bit(MD_RECOVERY_NEEDED, &rdev->mddev->recovery);
1935 		md_wakeup_thread(rdev->mddev->thread);
1936 
1937 		err = 0;
1938 	}
1939 	if (!err)
1940 		sysfs_notify(&rdev->kobj, NULL, "state");
1941 	return err ? err : len;
1942 }
1943 static struct rdev_sysfs_entry rdev_state =
1944 __ATTR(state, S_IRUGO|S_IWUSR, state_show, state_store);
1945 
1946 static ssize_t
1947 errors_show(mdk_rdev_t *rdev, char *page)
1948 {
1949 	return sprintf(page, "%d\n", atomic_read(&rdev->corrected_errors));
1950 }
1951 
1952 static ssize_t
1953 errors_store(mdk_rdev_t *rdev, const char *buf, size_t len)
1954 {
1955 	char *e;
1956 	unsigned long n = simple_strtoul(buf, &e, 10);
1957 	if (*buf && (*e == 0 || *e == '\n')) {
1958 		atomic_set(&rdev->corrected_errors, n);
1959 		return len;
1960 	}
1961 	return -EINVAL;
1962 }
1963 static struct rdev_sysfs_entry rdev_errors =
1964 __ATTR(errors, S_IRUGO|S_IWUSR, errors_show, errors_store);
1965 
1966 static ssize_t
1967 slot_show(mdk_rdev_t *rdev, char *page)
1968 {
1969 	if (rdev->raid_disk < 0)
1970 		return sprintf(page, "none\n");
1971 	else
1972 		return sprintf(page, "%d\n", rdev->raid_disk);
1973 }
1974 
1975 static ssize_t
1976 slot_store(mdk_rdev_t *rdev, const char *buf, size_t len)
1977 {
1978 	char *e;
1979 	int err;
1980 	char nm[20];
1981 	int slot = simple_strtoul(buf, &e, 10);
1982 	if (strncmp(buf, "none", 4)==0)
1983 		slot = -1;
1984 	else if (e==buf || (*e && *e!= '\n'))
1985 		return -EINVAL;
1986 	if (rdev->mddev->pers && slot == -1) {
1987 		/* Setting 'slot' on an active array requires also
1988 		 * updating the 'rd%d' link, and communicating
1989 		 * with the personality with ->hot_*_disk.
1990 		 * For now we only support removing
1991 		 * failed/spare devices.  This normally happens automatically,
1992 		 * but not when the metadata is externally managed.
1993 		 */
1994 		if (rdev->raid_disk == -1)
1995 			return -EEXIST;
1996 		/* personality does all needed checks */
1997 		if (rdev->mddev->pers->hot_add_disk == NULL)
1998 			return -EINVAL;
1999 		err = rdev->mddev->pers->
2000 			hot_remove_disk(rdev->mddev, rdev->raid_disk);
2001 		if (err)
2002 			return err;
2003 		sprintf(nm, "rd%d", rdev->raid_disk);
2004 		sysfs_remove_link(&rdev->mddev->kobj, nm);
2005 		set_bit(MD_RECOVERY_NEEDED, &rdev->mddev->recovery);
2006 		md_wakeup_thread(rdev->mddev->thread);
2007 	} else if (rdev->mddev->pers) {
2008 		mdk_rdev_t *rdev2;
2009 		struct list_head *tmp;
2010 		/* Activating a spare .. or possibly reactivating
2011 		 * if we every get bitmaps working here.
2012 		 */
2013 
2014 		if (rdev->raid_disk != -1)
2015 			return -EBUSY;
2016 
2017 		if (rdev->mddev->pers->hot_add_disk == NULL)
2018 			return -EINVAL;
2019 
2020 		rdev_for_each(rdev2, tmp, rdev->mddev)
2021 			if (rdev2->raid_disk == slot)
2022 				return -EEXIST;
2023 
2024 		rdev->raid_disk = slot;
2025 		if (test_bit(In_sync, &rdev->flags))
2026 			rdev->saved_raid_disk = slot;
2027 		else
2028 			rdev->saved_raid_disk = -1;
2029 		err = rdev->mddev->pers->
2030 			hot_add_disk(rdev->mddev, rdev);
2031 		if (err) {
2032 			rdev->raid_disk = -1;
2033 			return err;
2034 		} else
2035 			sysfs_notify(&rdev->kobj, NULL, "state");
2036 		sprintf(nm, "rd%d", rdev->raid_disk);
2037 		if (sysfs_create_link(&rdev->mddev->kobj, &rdev->kobj, nm))
2038 			printk(KERN_WARNING
2039 			       "md: cannot register "
2040 			       "%s for %s\n",
2041 			       nm, mdname(rdev->mddev));
2042 
2043 		/* don't wakeup anyone, leave that to userspace. */
2044 	} else {
2045 		if (slot >= rdev->mddev->raid_disks)
2046 			return -ENOSPC;
2047 		rdev->raid_disk = slot;
2048 		/* assume it is working */
2049 		clear_bit(Faulty, &rdev->flags);
2050 		clear_bit(WriteMostly, &rdev->flags);
2051 		set_bit(In_sync, &rdev->flags);
2052 		sysfs_notify(&rdev->kobj, NULL, "state");
2053 	}
2054 	return len;
2055 }
2056 
2057 
2058 static struct rdev_sysfs_entry rdev_slot =
2059 __ATTR(slot, S_IRUGO|S_IWUSR, slot_show, slot_store);
2060 
2061 static ssize_t
2062 offset_show(mdk_rdev_t *rdev, char *page)
2063 {
2064 	return sprintf(page, "%llu\n", (unsigned long long)rdev->data_offset);
2065 }
2066 
2067 static ssize_t
2068 offset_store(mdk_rdev_t *rdev, const char *buf, size_t len)
2069 {
2070 	char *e;
2071 	unsigned long long offset = simple_strtoull(buf, &e, 10);
2072 	if (e==buf || (*e && *e != '\n'))
2073 		return -EINVAL;
2074 	if (rdev->mddev->pers && rdev->raid_disk >= 0)
2075 		return -EBUSY;
2076 	if (rdev->size && rdev->mddev->external)
2077 		/* Must set offset before size, so overlap checks
2078 		 * can be sane */
2079 		return -EBUSY;
2080 	rdev->data_offset = offset;
2081 	return len;
2082 }
2083 
2084 static struct rdev_sysfs_entry rdev_offset =
2085 __ATTR(offset, S_IRUGO|S_IWUSR, offset_show, offset_store);
2086 
2087 static ssize_t
2088 rdev_size_show(mdk_rdev_t *rdev, char *page)
2089 {
2090 	return sprintf(page, "%llu\n", (unsigned long long)rdev->size);
2091 }
2092 
2093 static int overlaps(sector_t s1, sector_t l1, sector_t s2, sector_t l2)
2094 {
2095 	/* check if two start/length pairs overlap */
2096 	if (s1+l1 <= s2)
2097 		return 0;
2098 	if (s2+l2 <= s1)
2099 		return 0;
2100 	return 1;
2101 }
2102 
2103 static ssize_t
2104 rdev_size_store(mdk_rdev_t *rdev, const char *buf, size_t len)
2105 {
2106 	unsigned long long size;
2107 	unsigned long long oldsize = rdev->size;
2108 	mddev_t *my_mddev = rdev->mddev;
2109 
2110 	if (strict_strtoull(buf, 10, &size) < 0)
2111 		return -EINVAL;
2112 	if (size < my_mddev->size)
2113 		return -EINVAL;
2114 	if (my_mddev->pers && rdev->raid_disk >= 0) {
2115 		if (my_mddev->persistent) {
2116 			size = super_types[my_mddev->major_version].
2117 				rdev_size_change(rdev, size * 2);
2118 			if (!size)
2119 				return -EBUSY;
2120 		} else if (!size) {
2121 			size = (rdev->bdev->bd_inode->i_size >> 10);
2122 			size -= rdev->data_offset/2;
2123 		}
2124 		if (size < my_mddev->size)
2125 			return -EINVAL; /* component must fit device */
2126 	}
2127 
2128 	rdev->size = size;
2129 	if (size > oldsize && my_mddev->external) {
2130 		/* need to check that all other rdevs with the same ->bdev
2131 		 * do not overlap.  We need to unlock the mddev to avoid
2132 		 * a deadlock.  We have already changed rdev->size, and if
2133 		 * we have to change it back, we will have the lock again.
2134 		 */
2135 		mddev_t *mddev;
2136 		int overlap = 0;
2137 		struct list_head *tmp, *tmp2;
2138 
2139 		mddev_unlock(my_mddev);
2140 		for_each_mddev(mddev, tmp) {
2141 			mdk_rdev_t *rdev2;
2142 
2143 			mddev_lock(mddev);
2144 			rdev_for_each(rdev2, tmp2, mddev)
2145 				if (test_bit(AllReserved, &rdev2->flags) ||
2146 				    (rdev->bdev == rdev2->bdev &&
2147 				     rdev != rdev2 &&
2148 				     overlaps(rdev->data_offset, rdev->size * 2,
2149 					      rdev2->data_offset,
2150 					      rdev2->size * 2))) {
2151 					overlap = 1;
2152 					break;
2153 				}
2154 			mddev_unlock(mddev);
2155 			if (overlap) {
2156 				mddev_put(mddev);
2157 				break;
2158 			}
2159 		}
2160 		mddev_lock(my_mddev);
2161 		if (overlap) {
2162 			/* Someone else could have slipped in a size
2163 			 * change here, but doing so is just silly.
2164 			 * We put oldsize back because we *know* it is
2165 			 * safe, and trust userspace not to race with
2166 			 * itself
2167 			 */
2168 			rdev->size = oldsize;
2169 			return -EBUSY;
2170 		}
2171 	}
2172 	return len;
2173 }
2174 
2175 static struct rdev_sysfs_entry rdev_size =
2176 __ATTR(size, S_IRUGO|S_IWUSR, rdev_size_show, rdev_size_store);
2177 
2178 static struct attribute *rdev_default_attrs[] = {
2179 	&rdev_state.attr,
2180 	&rdev_errors.attr,
2181 	&rdev_slot.attr,
2182 	&rdev_offset.attr,
2183 	&rdev_size.attr,
2184 	NULL,
2185 };
2186 static ssize_t
2187 rdev_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
2188 {
2189 	struct rdev_sysfs_entry *entry = container_of(attr, struct rdev_sysfs_entry, attr);
2190 	mdk_rdev_t *rdev = container_of(kobj, mdk_rdev_t, kobj);
2191 	mddev_t *mddev = rdev->mddev;
2192 	ssize_t rv;
2193 
2194 	if (!entry->show)
2195 		return -EIO;
2196 
2197 	rv = mddev ? mddev_lock(mddev) : -EBUSY;
2198 	if (!rv) {
2199 		if (rdev->mddev == NULL)
2200 			rv = -EBUSY;
2201 		else
2202 			rv = entry->show(rdev, page);
2203 		mddev_unlock(mddev);
2204 	}
2205 	return rv;
2206 }
2207 
2208 static ssize_t
2209 rdev_attr_store(struct kobject *kobj, struct attribute *attr,
2210 	      const char *page, size_t length)
2211 {
2212 	struct rdev_sysfs_entry *entry = container_of(attr, struct rdev_sysfs_entry, attr);
2213 	mdk_rdev_t *rdev = container_of(kobj, mdk_rdev_t, kobj);
2214 	ssize_t rv;
2215 	mddev_t *mddev = rdev->mddev;
2216 
2217 	if (!entry->store)
2218 		return -EIO;
2219 	if (!capable(CAP_SYS_ADMIN))
2220 		return -EACCES;
2221 	rv = mddev ? mddev_lock(mddev): -EBUSY;
2222 	if (!rv) {
2223 		if (rdev->mddev == NULL)
2224 			rv = -EBUSY;
2225 		else
2226 			rv = entry->store(rdev, page, length);
2227 		mddev_unlock(mddev);
2228 	}
2229 	return rv;
2230 }
2231 
2232 static void rdev_free(struct kobject *ko)
2233 {
2234 	mdk_rdev_t *rdev = container_of(ko, mdk_rdev_t, kobj);
2235 	kfree(rdev);
2236 }
2237 static struct sysfs_ops rdev_sysfs_ops = {
2238 	.show		= rdev_attr_show,
2239 	.store		= rdev_attr_store,
2240 };
2241 static struct kobj_type rdev_ktype = {
2242 	.release	= rdev_free,
2243 	.sysfs_ops	= &rdev_sysfs_ops,
2244 	.default_attrs	= rdev_default_attrs,
2245 };
2246 
2247 /*
2248  * Import a device. If 'super_format' >= 0, then sanity check the superblock
2249  *
2250  * mark the device faulty if:
2251  *
2252  *   - the device is nonexistent (zero size)
2253  *   - the device has no valid superblock
2254  *
2255  * a faulty rdev _never_ has rdev->sb set.
2256  */
2257 static mdk_rdev_t *md_import_device(dev_t newdev, int super_format, int super_minor)
2258 {
2259 	char b[BDEVNAME_SIZE];
2260 	int err;
2261 	mdk_rdev_t *rdev;
2262 	sector_t size;
2263 
2264 	rdev = kzalloc(sizeof(*rdev), GFP_KERNEL);
2265 	if (!rdev) {
2266 		printk(KERN_ERR "md: could not alloc mem for new device!\n");
2267 		return ERR_PTR(-ENOMEM);
2268 	}
2269 
2270 	if ((err = alloc_disk_sb(rdev)))
2271 		goto abort_free;
2272 
2273 	err = lock_rdev(rdev, newdev, super_format == -2);
2274 	if (err)
2275 		goto abort_free;
2276 
2277 	kobject_init(&rdev->kobj, &rdev_ktype);
2278 
2279 	rdev->desc_nr = -1;
2280 	rdev->saved_raid_disk = -1;
2281 	rdev->raid_disk = -1;
2282 	rdev->flags = 0;
2283 	rdev->data_offset = 0;
2284 	rdev->sb_events = 0;
2285 	atomic_set(&rdev->nr_pending, 0);
2286 	atomic_set(&rdev->read_errors, 0);
2287 	atomic_set(&rdev->corrected_errors, 0);
2288 
2289 	size = rdev->bdev->bd_inode->i_size >> BLOCK_SIZE_BITS;
2290 	if (!size) {
2291 		printk(KERN_WARNING
2292 			"md: %s has zero or unknown size, marking faulty!\n",
2293 			bdevname(rdev->bdev,b));
2294 		err = -EINVAL;
2295 		goto abort_free;
2296 	}
2297 
2298 	if (super_format >= 0) {
2299 		err = super_types[super_format].
2300 			load_super(rdev, NULL, super_minor);
2301 		if (err == -EINVAL) {
2302 			printk(KERN_WARNING
2303 				"md: %s does not have a valid v%d.%d "
2304 			       "superblock, not importing!\n",
2305 				bdevname(rdev->bdev,b),
2306 			       super_format, super_minor);
2307 			goto abort_free;
2308 		}
2309 		if (err < 0) {
2310 			printk(KERN_WARNING
2311 				"md: could not read %s's sb, not importing!\n",
2312 				bdevname(rdev->bdev,b));
2313 			goto abort_free;
2314 		}
2315 	}
2316 
2317 	INIT_LIST_HEAD(&rdev->same_set);
2318 	init_waitqueue_head(&rdev->blocked_wait);
2319 
2320 	return rdev;
2321 
2322 abort_free:
2323 	if (rdev->sb_page) {
2324 		if (rdev->bdev)
2325 			unlock_rdev(rdev);
2326 		free_disk_sb(rdev);
2327 	}
2328 	kfree(rdev);
2329 	return ERR_PTR(err);
2330 }
2331 
2332 /*
2333  * Check a full RAID array for plausibility
2334  */
2335 
2336 
2337 static void analyze_sbs(mddev_t * mddev)
2338 {
2339 	int i;
2340 	struct list_head *tmp;
2341 	mdk_rdev_t *rdev, *freshest;
2342 	char b[BDEVNAME_SIZE];
2343 
2344 	freshest = NULL;
2345 	rdev_for_each(rdev, tmp, mddev)
2346 		switch (super_types[mddev->major_version].
2347 			load_super(rdev, freshest, mddev->minor_version)) {
2348 		case 1:
2349 			freshest = rdev;
2350 			break;
2351 		case 0:
2352 			break;
2353 		default:
2354 			printk( KERN_ERR \
2355 				"md: fatal superblock inconsistency in %s"
2356 				" -- removing from array\n",
2357 				bdevname(rdev->bdev,b));
2358 			kick_rdev_from_array(rdev);
2359 		}
2360 
2361 
2362 	super_types[mddev->major_version].
2363 		validate_super(mddev, freshest);
2364 
2365 	i = 0;
2366 	rdev_for_each(rdev, tmp, mddev) {
2367 		if (rdev != freshest)
2368 			if (super_types[mddev->major_version].
2369 			    validate_super(mddev, rdev)) {
2370 				printk(KERN_WARNING "md: kicking non-fresh %s"
2371 					" from array!\n",
2372 					bdevname(rdev->bdev,b));
2373 				kick_rdev_from_array(rdev);
2374 				continue;
2375 			}
2376 		if (mddev->level == LEVEL_MULTIPATH) {
2377 			rdev->desc_nr = i++;
2378 			rdev->raid_disk = rdev->desc_nr;
2379 			set_bit(In_sync, &rdev->flags);
2380 		} else if (rdev->raid_disk >= mddev->raid_disks) {
2381 			rdev->raid_disk = -1;
2382 			clear_bit(In_sync, &rdev->flags);
2383 		}
2384 	}
2385 
2386 
2387 
2388 	if (mddev->recovery_cp != MaxSector &&
2389 	    mddev->level >= 1)
2390 		printk(KERN_ERR "md: %s: raid array is not clean"
2391 		       " -- starting background reconstruction\n",
2392 		       mdname(mddev));
2393 
2394 }
2395 
2396 static void md_safemode_timeout(unsigned long data);
2397 
2398 static ssize_t
2399 safe_delay_show(mddev_t *mddev, char *page)
2400 {
2401 	int msec = (mddev->safemode_delay*1000)/HZ;
2402 	return sprintf(page, "%d.%03d\n", msec/1000, msec%1000);
2403 }
2404 static ssize_t
2405 safe_delay_store(mddev_t *mddev, const char *cbuf, size_t len)
2406 {
2407 	int scale=1;
2408 	int dot=0;
2409 	int i;
2410 	unsigned long msec;
2411 	char buf[30];
2412 	char *e;
2413 	/* remove a period, and count digits after it */
2414 	if (len >= sizeof(buf))
2415 		return -EINVAL;
2416 	strlcpy(buf, cbuf, len);
2417 	buf[len] = 0;
2418 	for (i=0; i<len; i++) {
2419 		if (dot) {
2420 			if (isdigit(buf[i])) {
2421 				buf[i-1] = buf[i];
2422 				scale *= 10;
2423 			}
2424 			buf[i] = 0;
2425 		} else if (buf[i] == '.') {
2426 			dot=1;
2427 			buf[i] = 0;
2428 		}
2429 	}
2430 	msec = simple_strtoul(buf, &e, 10);
2431 	if (e == buf || (*e && *e != '\n'))
2432 		return -EINVAL;
2433 	msec = (msec * 1000) / scale;
2434 	if (msec == 0)
2435 		mddev->safemode_delay = 0;
2436 	else {
2437 		unsigned long old_delay = mddev->safemode_delay;
2438 		mddev->safemode_delay = (msec*HZ)/1000;
2439 		if (mddev->safemode_delay == 0)
2440 			mddev->safemode_delay = 1;
2441 		if (mddev->safemode_delay < old_delay)
2442 			md_safemode_timeout((unsigned long)mddev);
2443 	}
2444 	return len;
2445 }
2446 static struct md_sysfs_entry md_safe_delay =
2447 __ATTR(safe_mode_delay, S_IRUGO|S_IWUSR,safe_delay_show, safe_delay_store);
2448 
2449 static ssize_t
2450 level_show(mddev_t *mddev, char *page)
2451 {
2452 	struct mdk_personality *p = mddev->pers;
2453 	if (p)
2454 		return sprintf(page, "%s\n", p->name);
2455 	else if (mddev->clevel[0])
2456 		return sprintf(page, "%s\n", mddev->clevel);
2457 	else if (mddev->level != LEVEL_NONE)
2458 		return sprintf(page, "%d\n", mddev->level);
2459 	else
2460 		return 0;
2461 }
2462 
2463 static ssize_t
2464 level_store(mddev_t *mddev, const char *buf, size_t len)
2465 {
2466 	ssize_t rv = len;
2467 	if (mddev->pers)
2468 		return -EBUSY;
2469 	if (len == 0)
2470 		return 0;
2471 	if (len >= sizeof(mddev->clevel))
2472 		return -ENOSPC;
2473 	strncpy(mddev->clevel, buf, len);
2474 	if (mddev->clevel[len-1] == '\n')
2475 		len--;
2476 	mddev->clevel[len] = 0;
2477 	mddev->level = LEVEL_NONE;
2478 	return rv;
2479 }
2480 
2481 static struct md_sysfs_entry md_level =
2482 __ATTR(level, S_IRUGO|S_IWUSR, level_show, level_store);
2483 
2484 
2485 static ssize_t
2486 layout_show(mddev_t *mddev, char *page)
2487 {
2488 	/* just a number, not meaningful for all levels */
2489 	if (mddev->reshape_position != MaxSector &&
2490 	    mddev->layout != mddev->new_layout)
2491 		return sprintf(page, "%d (%d)\n",
2492 			       mddev->new_layout, mddev->layout);
2493 	return sprintf(page, "%d\n", mddev->layout);
2494 }
2495 
2496 static ssize_t
2497 layout_store(mddev_t *mddev, const char *buf, size_t len)
2498 {
2499 	char *e;
2500 	unsigned long n = simple_strtoul(buf, &e, 10);
2501 
2502 	if (!*buf || (*e && *e != '\n'))
2503 		return -EINVAL;
2504 
2505 	if (mddev->pers)
2506 		return -EBUSY;
2507 	if (mddev->reshape_position != MaxSector)
2508 		mddev->new_layout = n;
2509 	else
2510 		mddev->layout = n;
2511 	return len;
2512 }
2513 static struct md_sysfs_entry md_layout =
2514 __ATTR(layout, S_IRUGO|S_IWUSR, layout_show, layout_store);
2515 
2516 
2517 static ssize_t
2518 raid_disks_show(mddev_t *mddev, char *page)
2519 {
2520 	if (mddev->raid_disks == 0)
2521 		return 0;
2522 	if (mddev->reshape_position != MaxSector &&
2523 	    mddev->delta_disks != 0)
2524 		return sprintf(page, "%d (%d)\n", mddev->raid_disks,
2525 			       mddev->raid_disks - mddev->delta_disks);
2526 	return sprintf(page, "%d\n", mddev->raid_disks);
2527 }
2528 
2529 static int update_raid_disks(mddev_t *mddev, int raid_disks);
2530 
2531 static ssize_t
2532 raid_disks_store(mddev_t *mddev, const char *buf, size_t len)
2533 {
2534 	char *e;
2535 	int rv = 0;
2536 	unsigned long n = simple_strtoul(buf, &e, 10);
2537 
2538 	if (!*buf || (*e && *e != '\n'))
2539 		return -EINVAL;
2540 
2541 	if (mddev->pers)
2542 		rv = update_raid_disks(mddev, n);
2543 	else if (mddev->reshape_position != MaxSector) {
2544 		int olddisks = mddev->raid_disks - mddev->delta_disks;
2545 		mddev->delta_disks = n - olddisks;
2546 		mddev->raid_disks = n;
2547 	} else
2548 		mddev->raid_disks = n;
2549 	return rv ? rv : len;
2550 }
2551 static struct md_sysfs_entry md_raid_disks =
2552 __ATTR(raid_disks, S_IRUGO|S_IWUSR, raid_disks_show, raid_disks_store);
2553 
2554 static ssize_t
2555 chunk_size_show(mddev_t *mddev, char *page)
2556 {
2557 	if (mddev->reshape_position != MaxSector &&
2558 	    mddev->chunk_size != mddev->new_chunk)
2559 		return sprintf(page, "%d (%d)\n", mddev->new_chunk,
2560 			       mddev->chunk_size);
2561 	return sprintf(page, "%d\n", mddev->chunk_size);
2562 }
2563 
2564 static ssize_t
2565 chunk_size_store(mddev_t *mddev, const char *buf, size_t len)
2566 {
2567 	/* can only set chunk_size if array is not yet active */
2568 	char *e;
2569 	unsigned long n = simple_strtoul(buf, &e, 10);
2570 
2571 	if (!*buf || (*e && *e != '\n'))
2572 		return -EINVAL;
2573 
2574 	if (mddev->pers)
2575 		return -EBUSY;
2576 	else if (mddev->reshape_position != MaxSector)
2577 		mddev->new_chunk = n;
2578 	else
2579 		mddev->chunk_size = n;
2580 	return len;
2581 }
2582 static struct md_sysfs_entry md_chunk_size =
2583 __ATTR(chunk_size, S_IRUGO|S_IWUSR, chunk_size_show, chunk_size_store);
2584 
2585 static ssize_t
2586 resync_start_show(mddev_t *mddev, char *page)
2587 {
2588 	return sprintf(page, "%llu\n", (unsigned long long)mddev->recovery_cp);
2589 }
2590 
2591 static ssize_t
2592 resync_start_store(mddev_t *mddev, const char *buf, size_t len)
2593 {
2594 	char *e;
2595 	unsigned long long n = simple_strtoull(buf, &e, 10);
2596 
2597 	if (mddev->pers)
2598 		return -EBUSY;
2599 	if (!*buf || (*e && *e != '\n'))
2600 		return -EINVAL;
2601 
2602 	mddev->recovery_cp = n;
2603 	return len;
2604 }
2605 static struct md_sysfs_entry md_resync_start =
2606 __ATTR(resync_start, S_IRUGO|S_IWUSR, resync_start_show, resync_start_store);
2607 
2608 /*
2609  * The array state can be:
2610  *
2611  * clear
2612  *     No devices, no size, no level
2613  *     Equivalent to STOP_ARRAY ioctl
2614  * inactive
2615  *     May have some settings, but array is not active
2616  *        all IO results in error
2617  *     When written, doesn't tear down array, but just stops it
2618  * suspended (not supported yet)
2619  *     All IO requests will block. The array can be reconfigured.
2620  *     Writing this, if accepted, will block until array is quiescent
2621  * readonly
2622  *     no resync can happen.  no superblocks get written.
2623  *     write requests fail
2624  * read-auto
2625  *     like readonly, but behaves like 'clean' on a write request.
2626  *
2627  * clean - no pending writes, but otherwise active.
2628  *     When written to inactive array, starts without resync
2629  *     If a write request arrives then
2630  *       if metadata is known, mark 'dirty' and switch to 'active'.
2631  *       if not known, block and switch to write-pending
2632  *     If written to an active array that has pending writes, then fails.
2633  * active
2634  *     fully active: IO and resync can be happening.
2635  *     When written to inactive array, starts with resync
2636  *
2637  * write-pending
2638  *     clean, but writes are blocked waiting for 'active' to be written.
2639  *
2640  * active-idle
2641  *     like active, but no writes have been seen for a while (100msec).
2642  *
2643  */
2644 enum array_state { clear, inactive, suspended, readonly, read_auto, clean, active,
2645 		   write_pending, active_idle, bad_word};
2646 static char *array_states[] = {
2647 	"clear", "inactive", "suspended", "readonly", "read-auto", "clean", "active",
2648 	"write-pending", "active-idle", NULL };
2649 
2650 static int match_word(const char *word, char **list)
2651 {
2652 	int n;
2653 	for (n=0; list[n]; n++)
2654 		if (cmd_match(word, list[n]))
2655 			break;
2656 	return n;
2657 }
2658 
2659 static ssize_t
2660 array_state_show(mddev_t *mddev, char *page)
2661 {
2662 	enum array_state st = inactive;
2663 
2664 	if (mddev->pers)
2665 		switch(mddev->ro) {
2666 		case 1:
2667 			st = readonly;
2668 			break;
2669 		case 2:
2670 			st = read_auto;
2671 			break;
2672 		case 0:
2673 			if (mddev->in_sync)
2674 				st = clean;
2675 			else if (test_bit(MD_CHANGE_CLEAN, &mddev->flags))
2676 				st = write_pending;
2677 			else if (mddev->safemode)
2678 				st = active_idle;
2679 			else
2680 				st = active;
2681 		}
2682 	else {
2683 		if (list_empty(&mddev->disks) &&
2684 		    mddev->raid_disks == 0 &&
2685 		    mddev->size == 0)
2686 			st = clear;
2687 		else
2688 			st = inactive;
2689 	}
2690 	return sprintf(page, "%s\n", array_states[st]);
2691 }
2692 
2693 static int do_md_stop(mddev_t * mddev, int ro, int is_open);
2694 static int do_md_run(mddev_t * mddev);
2695 static int restart_array(mddev_t *mddev);
2696 
2697 static ssize_t
2698 array_state_store(mddev_t *mddev, const char *buf, size_t len)
2699 {
2700 	int err = -EINVAL;
2701 	enum array_state st = match_word(buf, array_states);
2702 	switch(st) {
2703 	case bad_word:
2704 		break;
2705 	case clear:
2706 		/* stopping an active array */
2707 		if (atomic_read(&mddev->openers) > 0)
2708 			return -EBUSY;
2709 		err = do_md_stop(mddev, 0, 0);
2710 		break;
2711 	case inactive:
2712 		/* stopping an active array */
2713 		if (mddev->pers) {
2714 			if (atomic_read(&mddev->openers) > 0)
2715 				return -EBUSY;
2716 			err = do_md_stop(mddev, 2, 0);
2717 		} else
2718 			err = 0; /* already inactive */
2719 		break;
2720 	case suspended:
2721 		break; /* not supported yet */
2722 	case readonly:
2723 		if (mddev->pers)
2724 			err = do_md_stop(mddev, 1, 0);
2725 		else {
2726 			mddev->ro = 1;
2727 			set_disk_ro(mddev->gendisk, 1);
2728 			err = do_md_run(mddev);
2729 		}
2730 		break;
2731 	case read_auto:
2732 		if (mddev->pers) {
2733 			if (mddev->ro != 1)
2734 				err = do_md_stop(mddev, 1, 0);
2735 			else
2736 				err = restart_array(mddev);
2737 			if (err == 0) {
2738 				mddev->ro = 2;
2739 				set_disk_ro(mddev->gendisk, 0);
2740 			}
2741 		} else {
2742 			mddev->ro = 2;
2743 			err = do_md_run(mddev);
2744 		}
2745 		break;
2746 	case clean:
2747 		if (mddev->pers) {
2748 			restart_array(mddev);
2749 			spin_lock_irq(&mddev->write_lock);
2750 			if (atomic_read(&mddev->writes_pending) == 0) {
2751 				if (mddev->in_sync == 0) {
2752 					mddev->in_sync = 1;
2753 					if (mddev->safemode == 1)
2754 						mddev->safemode = 0;
2755 					if (mddev->persistent)
2756 						set_bit(MD_CHANGE_CLEAN,
2757 							&mddev->flags);
2758 				}
2759 				err = 0;
2760 			} else
2761 				err = -EBUSY;
2762 			spin_unlock_irq(&mddev->write_lock);
2763 		} else {
2764 			mddev->ro = 0;
2765 			mddev->recovery_cp = MaxSector;
2766 			err = do_md_run(mddev);
2767 		}
2768 		break;
2769 	case active:
2770 		if (mddev->pers) {
2771 			restart_array(mddev);
2772 			if (mddev->external)
2773 				clear_bit(MD_CHANGE_CLEAN, &mddev->flags);
2774 			wake_up(&mddev->sb_wait);
2775 			err = 0;
2776 		} else {
2777 			mddev->ro = 0;
2778 			set_disk_ro(mddev->gendisk, 0);
2779 			err = do_md_run(mddev);
2780 		}
2781 		break;
2782 	case write_pending:
2783 	case active_idle:
2784 		/* these cannot be set */
2785 		break;
2786 	}
2787 	if (err)
2788 		return err;
2789 	else {
2790 		sysfs_notify(&mddev->kobj, NULL, "array_state");
2791 		return len;
2792 	}
2793 }
2794 static struct md_sysfs_entry md_array_state =
2795 __ATTR(array_state, S_IRUGO|S_IWUSR, array_state_show, array_state_store);
2796 
2797 static ssize_t
2798 null_show(mddev_t *mddev, char *page)
2799 {
2800 	return -EINVAL;
2801 }
2802 
2803 static ssize_t
2804 new_dev_store(mddev_t *mddev, const char *buf, size_t len)
2805 {
2806 	/* buf must be %d:%d\n? giving major and minor numbers */
2807 	/* The new device is added to the array.
2808 	 * If the array has a persistent superblock, we read the
2809 	 * superblock to initialise info and check validity.
2810 	 * Otherwise, only checking done is that in bind_rdev_to_array,
2811 	 * which mainly checks size.
2812 	 */
2813 	char *e;
2814 	int major = simple_strtoul(buf, &e, 10);
2815 	int minor;
2816 	dev_t dev;
2817 	mdk_rdev_t *rdev;
2818 	int err;
2819 
2820 	if (!*buf || *e != ':' || !e[1] || e[1] == '\n')
2821 		return -EINVAL;
2822 	minor = simple_strtoul(e+1, &e, 10);
2823 	if (*e && *e != '\n')
2824 		return -EINVAL;
2825 	dev = MKDEV(major, minor);
2826 	if (major != MAJOR(dev) ||
2827 	    minor != MINOR(dev))
2828 		return -EOVERFLOW;
2829 
2830 
2831 	if (mddev->persistent) {
2832 		rdev = md_import_device(dev, mddev->major_version,
2833 					mddev->minor_version);
2834 		if (!IS_ERR(rdev) && !list_empty(&mddev->disks)) {
2835 			mdk_rdev_t *rdev0 = list_entry(mddev->disks.next,
2836 						       mdk_rdev_t, same_set);
2837 			err = super_types[mddev->major_version]
2838 				.load_super(rdev, rdev0, mddev->minor_version);
2839 			if (err < 0)
2840 				goto out;
2841 		}
2842 	} else if (mddev->external)
2843 		rdev = md_import_device(dev, -2, -1);
2844 	else
2845 		rdev = md_import_device(dev, -1, -1);
2846 
2847 	if (IS_ERR(rdev))
2848 		return PTR_ERR(rdev);
2849 	err = bind_rdev_to_array(rdev, mddev);
2850  out:
2851 	if (err)
2852 		export_rdev(rdev);
2853 	return err ? err : len;
2854 }
2855 
2856 static struct md_sysfs_entry md_new_device =
2857 __ATTR(new_dev, S_IWUSR, null_show, new_dev_store);
2858 
2859 static ssize_t
2860 bitmap_store(mddev_t *mddev, const char *buf, size_t len)
2861 {
2862 	char *end;
2863 	unsigned long chunk, end_chunk;
2864 
2865 	if (!mddev->bitmap)
2866 		goto out;
2867 	/* buf should be <chunk> <chunk> ... or <chunk>-<chunk> ... (range) */
2868 	while (*buf) {
2869 		chunk = end_chunk = simple_strtoul(buf, &end, 0);
2870 		if (buf == end) break;
2871 		if (*end == '-') { /* range */
2872 			buf = end + 1;
2873 			end_chunk = simple_strtoul(buf, &end, 0);
2874 			if (buf == end) break;
2875 		}
2876 		if (*end && !isspace(*end)) break;
2877 		bitmap_dirty_bits(mddev->bitmap, chunk, end_chunk);
2878 		buf = end;
2879 		while (isspace(*buf)) buf++;
2880 	}
2881 	bitmap_unplug(mddev->bitmap); /* flush the bits to disk */
2882 out:
2883 	return len;
2884 }
2885 
2886 static struct md_sysfs_entry md_bitmap =
2887 __ATTR(bitmap_set_bits, S_IWUSR, null_show, bitmap_store);
2888 
2889 static ssize_t
2890 size_show(mddev_t *mddev, char *page)
2891 {
2892 	return sprintf(page, "%llu\n", (unsigned long long)mddev->size);
2893 }
2894 
2895 static int update_size(mddev_t *mddev, sector_t num_sectors);
2896 
2897 static ssize_t
2898 size_store(mddev_t *mddev, const char *buf, size_t len)
2899 {
2900 	/* If array is inactive, we can reduce the component size, but
2901 	 * not increase it (except from 0).
2902 	 * If array is active, we can try an on-line resize
2903 	 */
2904 	char *e;
2905 	int err = 0;
2906 	unsigned long long size = simple_strtoull(buf, &e, 10);
2907 	if (!*buf || *buf == '\n' ||
2908 	    (*e && *e != '\n'))
2909 		return -EINVAL;
2910 
2911 	if (mddev->pers) {
2912 		err = update_size(mddev, size * 2);
2913 		md_update_sb(mddev, 1);
2914 	} else {
2915 		if (mddev->size == 0 ||
2916 		    mddev->size > size)
2917 			mddev->size = size;
2918 		else
2919 			err = -ENOSPC;
2920 	}
2921 	return err ? err : len;
2922 }
2923 
2924 static struct md_sysfs_entry md_size =
2925 __ATTR(component_size, S_IRUGO|S_IWUSR, size_show, size_store);
2926 
2927 
2928 /* Metdata version.
2929  * This is one of
2930  *   'none' for arrays with no metadata (good luck...)
2931  *   'external' for arrays with externally managed metadata,
2932  * or N.M for internally known formats
2933  */
2934 static ssize_t
2935 metadata_show(mddev_t *mddev, char *page)
2936 {
2937 	if (mddev->persistent)
2938 		return sprintf(page, "%d.%d\n",
2939 			       mddev->major_version, mddev->minor_version);
2940 	else if (mddev->external)
2941 		return sprintf(page, "external:%s\n", mddev->metadata_type);
2942 	else
2943 		return sprintf(page, "none\n");
2944 }
2945 
2946 static ssize_t
2947 metadata_store(mddev_t *mddev, const char *buf, size_t len)
2948 {
2949 	int major, minor;
2950 	char *e;
2951 	if (!list_empty(&mddev->disks))
2952 		return -EBUSY;
2953 
2954 	if (cmd_match(buf, "none")) {
2955 		mddev->persistent = 0;
2956 		mddev->external = 0;
2957 		mddev->major_version = 0;
2958 		mddev->minor_version = 90;
2959 		return len;
2960 	}
2961 	if (strncmp(buf, "external:", 9) == 0) {
2962 		size_t namelen = len-9;
2963 		if (namelen >= sizeof(mddev->metadata_type))
2964 			namelen = sizeof(mddev->metadata_type)-1;
2965 		strncpy(mddev->metadata_type, buf+9, namelen);
2966 		mddev->metadata_type[namelen] = 0;
2967 		if (namelen && mddev->metadata_type[namelen-1] == '\n')
2968 			mddev->metadata_type[--namelen] = 0;
2969 		mddev->persistent = 0;
2970 		mddev->external = 1;
2971 		mddev->major_version = 0;
2972 		mddev->minor_version = 90;
2973 		return len;
2974 	}
2975 	major = simple_strtoul(buf, &e, 10);
2976 	if (e==buf || *e != '.')
2977 		return -EINVAL;
2978 	buf = e+1;
2979 	minor = simple_strtoul(buf, &e, 10);
2980 	if (e==buf || (*e && *e != '\n') )
2981 		return -EINVAL;
2982 	if (major >= ARRAY_SIZE(super_types) || super_types[major].name == NULL)
2983 		return -ENOENT;
2984 	mddev->major_version = major;
2985 	mddev->minor_version = minor;
2986 	mddev->persistent = 1;
2987 	mddev->external = 0;
2988 	return len;
2989 }
2990 
2991 static struct md_sysfs_entry md_metadata =
2992 __ATTR(metadata_version, S_IRUGO|S_IWUSR, metadata_show, metadata_store);
2993 
2994 static ssize_t
2995 action_show(mddev_t *mddev, char *page)
2996 {
2997 	char *type = "idle";
2998 	if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
2999 	    (!mddev->ro && test_bit(MD_RECOVERY_NEEDED, &mddev->recovery))) {
3000 		if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
3001 			type = "reshape";
3002 		else if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
3003 			if (!test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
3004 				type = "resync";
3005 			else if (test_bit(MD_RECOVERY_CHECK, &mddev->recovery))
3006 				type = "check";
3007 			else
3008 				type = "repair";
3009 		} else if (test_bit(MD_RECOVERY_RECOVER, &mddev->recovery))
3010 			type = "recover";
3011 	}
3012 	return sprintf(page, "%s\n", type);
3013 }
3014 
3015 static ssize_t
3016 action_store(mddev_t *mddev, const char *page, size_t len)
3017 {
3018 	if (!mddev->pers || !mddev->pers->sync_request)
3019 		return -EINVAL;
3020 
3021 	if (cmd_match(page, "idle")) {
3022 		if (mddev->sync_thread) {
3023 			set_bit(MD_RECOVERY_INTR, &mddev->recovery);
3024 			md_unregister_thread(mddev->sync_thread);
3025 			mddev->sync_thread = NULL;
3026 			mddev->recovery = 0;
3027 		}
3028 	} else if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
3029 		   test_bit(MD_RECOVERY_NEEDED, &mddev->recovery))
3030 		return -EBUSY;
3031 	else if (cmd_match(page, "resync"))
3032 		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
3033 	else if (cmd_match(page, "recover")) {
3034 		set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
3035 		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
3036 	} else if (cmd_match(page, "reshape")) {
3037 		int err;
3038 		if (mddev->pers->start_reshape == NULL)
3039 			return -EINVAL;
3040 		err = mddev->pers->start_reshape(mddev);
3041 		if (err)
3042 			return err;
3043 		sysfs_notify(&mddev->kobj, NULL, "degraded");
3044 	} else {
3045 		if (cmd_match(page, "check"))
3046 			set_bit(MD_RECOVERY_CHECK, &mddev->recovery);
3047 		else if (!cmd_match(page, "repair"))
3048 			return -EINVAL;
3049 		set_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
3050 		set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
3051 	}
3052 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
3053 	md_wakeup_thread(mddev->thread);
3054 	sysfs_notify(&mddev->kobj, NULL, "sync_action");
3055 	return len;
3056 }
3057 
3058 static ssize_t
3059 mismatch_cnt_show(mddev_t *mddev, char *page)
3060 {
3061 	return sprintf(page, "%llu\n",
3062 		       (unsigned long long) mddev->resync_mismatches);
3063 }
3064 
3065 static struct md_sysfs_entry md_scan_mode =
3066 __ATTR(sync_action, S_IRUGO|S_IWUSR, action_show, action_store);
3067 
3068 
3069 static struct md_sysfs_entry md_mismatches = __ATTR_RO(mismatch_cnt);
3070 
3071 static ssize_t
3072 sync_min_show(mddev_t *mddev, char *page)
3073 {
3074 	return sprintf(page, "%d (%s)\n", speed_min(mddev),
3075 		       mddev->sync_speed_min ? "local": "system");
3076 }
3077 
3078 static ssize_t
3079 sync_min_store(mddev_t *mddev, const char *buf, size_t len)
3080 {
3081 	int min;
3082 	char *e;
3083 	if (strncmp(buf, "system", 6)==0) {
3084 		mddev->sync_speed_min = 0;
3085 		return len;
3086 	}
3087 	min = simple_strtoul(buf, &e, 10);
3088 	if (buf == e || (*e && *e != '\n') || min <= 0)
3089 		return -EINVAL;
3090 	mddev->sync_speed_min = min;
3091 	return len;
3092 }
3093 
3094 static struct md_sysfs_entry md_sync_min =
3095 __ATTR(sync_speed_min, S_IRUGO|S_IWUSR, sync_min_show, sync_min_store);
3096 
3097 static ssize_t
3098 sync_max_show(mddev_t *mddev, char *page)
3099 {
3100 	return sprintf(page, "%d (%s)\n", speed_max(mddev),
3101 		       mddev->sync_speed_max ? "local": "system");
3102 }
3103 
3104 static ssize_t
3105 sync_max_store(mddev_t *mddev, const char *buf, size_t len)
3106 {
3107 	int max;
3108 	char *e;
3109 	if (strncmp(buf, "system", 6)==0) {
3110 		mddev->sync_speed_max = 0;
3111 		return len;
3112 	}
3113 	max = simple_strtoul(buf, &e, 10);
3114 	if (buf == e || (*e && *e != '\n') || max <= 0)
3115 		return -EINVAL;
3116 	mddev->sync_speed_max = max;
3117 	return len;
3118 }
3119 
3120 static struct md_sysfs_entry md_sync_max =
3121 __ATTR(sync_speed_max, S_IRUGO|S_IWUSR, sync_max_show, sync_max_store);
3122 
3123 static ssize_t
3124 degraded_show(mddev_t *mddev, char *page)
3125 {
3126 	return sprintf(page, "%d\n", mddev->degraded);
3127 }
3128 static struct md_sysfs_entry md_degraded = __ATTR_RO(degraded);
3129 
3130 static ssize_t
3131 sync_force_parallel_show(mddev_t *mddev, char *page)
3132 {
3133 	return sprintf(page, "%d\n", mddev->parallel_resync);
3134 }
3135 
3136 static ssize_t
3137 sync_force_parallel_store(mddev_t *mddev, const char *buf, size_t len)
3138 {
3139 	long n;
3140 
3141 	if (strict_strtol(buf, 10, &n))
3142 		return -EINVAL;
3143 
3144 	if (n != 0 && n != 1)
3145 		return -EINVAL;
3146 
3147 	mddev->parallel_resync = n;
3148 
3149 	if (mddev->sync_thread)
3150 		wake_up(&resync_wait);
3151 
3152 	return len;
3153 }
3154 
3155 /* force parallel resync, even with shared block devices */
3156 static struct md_sysfs_entry md_sync_force_parallel =
3157 __ATTR(sync_force_parallel, S_IRUGO|S_IWUSR,
3158        sync_force_parallel_show, sync_force_parallel_store);
3159 
3160 static ssize_t
3161 sync_speed_show(mddev_t *mddev, char *page)
3162 {
3163 	unsigned long resync, dt, db;
3164 	resync = mddev->curr_mark_cnt - atomic_read(&mddev->recovery_active);
3165 	dt = (jiffies - mddev->resync_mark) / HZ;
3166 	if (!dt) dt++;
3167 	db = resync - mddev->resync_mark_cnt;
3168 	return sprintf(page, "%lu\n", db/dt/2); /* K/sec */
3169 }
3170 
3171 static struct md_sysfs_entry md_sync_speed = __ATTR_RO(sync_speed);
3172 
3173 static ssize_t
3174 sync_completed_show(mddev_t *mddev, char *page)
3175 {
3176 	unsigned long max_blocks, resync;
3177 
3178 	if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery))
3179 		max_blocks = mddev->resync_max_sectors;
3180 	else
3181 		max_blocks = mddev->size << 1;
3182 
3183 	resync = (mddev->curr_resync - atomic_read(&mddev->recovery_active));
3184 	return sprintf(page, "%lu / %lu\n", resync, max_blocks);
3185 }
3186 
3187 static struct md_sysfs_entry md_sync_completed = __ATTR_RO(sync_completed);
3188 
3189 static ssize_t
3190 min_sync_show(mddev_t *mddev, char *page)
3191 {
3192 	return sprintf(page, "%llu\n",
3193 		       (unsigned long long)mddev->resync_min);
3194 }
3195 static ssize_t
3196 min_sync_store(mddev_t *mddev, const char *buf, size_t len)
3197 {
3198 	unsigned long long min;
3199 	if (strict_strtoull(buf, 10, &min))
3200 		return -EINVAL;
3201 	if (min > mddev->resync_max)
3202 		return -EINVAL;
3203 	if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
3204 		return -EBUSY;
3205 
3206 	/* Must be a multiple of chunk_size */
3207 	if (mddev->chunk_size) {
3208 		if (min & (sector_t)((mddev->chunk_size>>9)-1))
3209 			return -EINVAL;
3210 	}
3211 	mddev->resync_min = min;
3212 
3213 	return len;
3214 }
3215 
3216 static struct md_sysfs_entry md_min_sync =
3217 __ATTR(sync_min, S_IRUGO|S_IWUSR, min_sync_show, min_sync_store);
3218 
3219 static ssize_t
3220 max_sync_show(mddev_t *mddev, char *page)
3221 {
3222 	if (mddev->resync_max == MaxSector)
3223 		return sprintf(page, "max\n");
3224 	else
3225 		return sprintf(page, "%llu\n",
3226 			       (unsigned long long)mddev->resync_max);
3227 }
3228 static ssize_t
3229 max_sync_store(mddev_t *mddev, const char *buf, size_t len)
3230 {
3231 	if (strncmp(buf, "max", 3) == 0)
3232 		mddev->resync_max = MaxSector;
3233 	else {
3234 		unsigned long long max;
3235 		if (strict_strtoull(buf, 10, &max))
3236 			return -EINVAL;
3237 		if (max < mddev->resync_min)
3238 			return -EINVAL;
3239 		if (max < mddev->resync_max &&
3240 		    test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
3241 			return -EBUSY;
3242 
3243 		/* Must be a multiple of chunk_size */
3244 		if (mddev->chunk_size) {
3245 			if (max & (sector_t)((mddev->chunk_size>>9)-1))
3246 				return -EINVAL;
3247 		}
3248 		mddev->resync_max = max;
3249 	}
3250 	wake_up(&mddev->recovery_wait);
3251 	return len;
3252 }
3253 
3254 static struct md_sysfs_entry md_max_sync =
3255 __ATTR(sync_max, S_IRUGO|S_IWUSR, max_sync_show, max_sync_store);
3256 
3257 static ssize_t
3258 suspend_lo_show(mddev_t *mddev, char *page)
3259 {
3260 	return sprintf(page, "%llu\n", (unsigned long long)mddev->suspend_lo);
3261 }
3262 
3263 static ssize_t
3264 suspend_lo_store(mddev_t *mddev, const char *buf, size_t len)
3265 {
3266 	char *e;
3267 	unsigned long long new = simple_strtoull(buf, &e, 10);
3268 
3269 	if (mddev->pers->quiesce == NULL)
3270 		return -EINVAL;
3271 	if (buf == e || (*e && *e != '\n'))
3272 		return -EINVAL;
3273 	if (new >= mddev->suspend_hi ||
3274 	    (new > mddev->suspend_lo && new < mddev->suspend_hi)) {
3275 		mddev->suspend_lo = new;
3276 		mddev->pers->quiesce(mddev, 2);
3277 		return len;
3278 	} else
3279 		return -EINVAL;
3280 }
3281 static struct md_sysfs_entry md_suspend_lo =
3282 __ATTR(suspend_lo, S_IRUGO|S_IWUSR, suspend_lo_show, suspend_lo_store);
3283 
3284 
3285 static ssize_t
3286 suspend_hi_show(mddev_t *mddev, char *page)
3287 {
3288 	return sprintf(page, "%llu\n", (unsigned long long)mddev->suspend_hi);
3289 }
3290 
3291 static ssize_t
3292 suspend_hi_store(mddev_t *mddev, const char *buf, size_t len)
3293 {
3294 	char *e;
3295 	unsigned long long new = simple_strtoull(buf, &e, 10);
3296 
3297 	if (mddev->pers->quiesce == NULL)
3298 		return -EINVAL;
3299 	if (buf == e || (*e && *e != '\n'))
3300 		return -EINVAL;
3301 	if ((new <= mddev->suspend_lo && mddev->suspend_lo >= mddev->suspend_hi) ||
3302 	    (new > mddev->suspend_lo && new > mddev->suspend_hi)) {
3303 		mddev->suspend_hi = new;
3304 		mddev->pers->quiesce(mddev, 1);
3305 		mddev->pers->quiesce(mddev, 0);
3306 		return len;
3307 	} else
3308 		return -EINVAL;
3309 }
3310 static struct md_sysfs_entry md_suspend_hi =
3311 __ATTR(suspend_hi, S_IRUGO|S_IWUSR, suspend_hi_show, suspend_hi_store);
3312 
3313 static ssize_t
3314 reshape_position_show(mddev_t *mddev, char *page)
3315 {
3316 	if (mddev->reshape_position != MaxSector)
3317 		return sprintf(page, "%llu\n",
3318 			       (unsigned long long)mddev->reshape_position);
3319 	strcpy(page, "none\n");
3320 	return 5;
3321 }
3322 
3323 static ssize_t
3324 reshape_position_store(mddev_t *mddev, const char *buf, size_t len)
3325 {
3326 	char *e;
3327 	unsigned long long new = simple_strtoull(buf, &e, 10);
3328 	if (mddev->pers)
3329 		return -EBUSY;
3330 	if (buf == e || (*e && *e != '\n'))
3331 		return -EINVAL;
3332 	mddev->reshape_position = new;
3333 	mddev->delta_disks = 0;
3334 	mddev->new_level = mddev->level;
3335 	mddev->new_layout = mddev->layout;
3336 	mddev->new_chunk = mddev->chunk_size;
3337 	return len;
3338 }
3339 
3340 static struct md_sysfs_entry md_reshape_position =
3341 __ATTR(reshape_position, S_IRUGO|S_IWUSR, reshape_position_show,
3342        reshape_position_store);
3343 
3344 
3345 static struct attribute *md_default_attrs[] = {
3346 	&md_level.attr,
3347 	&md_layout.attr,
3348 	&md_raid_disks.attr,
3349 	&md_chunk_size.attr,
3350 	&md_size.attr,
3351 	&md_resync_start.attr,
3352 	&md_metadata.attr,
3353 	&md_new_device.attr,
3354 	&md_safe_delay.attr,
3355 	&md_array_state.attr,
3356 	&md_reshape_position.attr,
3357 	NULL,
3358 };
3359 
3360 static struct attribute *md_redundancy_attrs[] = {
3361 	&md_scan_mode.attr,
3362 	&md_mismatches.attr,
3363 	&md_sync_min.attr,
3364 	&md_sync_max.attr,
3365 	&md_sync_speed.attr,
3366 	&md_sync_force_parallel.attr,
3367 	&md_sync_completed.attr,
3368 	&md_min_sync.attr,
3369 	&md_max_sync.attr,
3370 	&md_suspend_lo.attr,
3371 	&md_suspend_hi.attr,
3372 	&md_bitmap.attr,
3373 	&md_degraded.attr,
3374 	NULL,
3375 };
3376 static struct attribute_group md_redundancy_group = {
3377 	.name = NULL,
3378 	.attrs = md_redundancy_attrs,
3379 };
3380 
3381 
3382 static ssize_t
3383 md_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
3384 {
3385 	struct md_sysfs_entry *entry = container_of(attr, struct md_sysfs_entry, attr);
3386 	mddev_t *mddev = container_of(kobj, struct mddev_s, kobj);
3387 	ssize_t rv;
3388 
3389 	if (!entry->show)
3390 		return -EIO;
3391 	rv = mddev_lock(mddev);
3392 	if (!rv) {
3393 		rv = entry->show(mddev, page);
3394 		mddev_unlock(mddev);
3395 	}
3396 	return rv;
3397 }
3398 
3399 static ssize_t
3400 md_attr_store(struct kobject *kobj, struct attribute *attr,
3401 	      const char *page, size_t length)
3402 {
3403 	struct md_sysfs_entry *entry = container_of(attr, struct md_sysfs_entry, attr);
3404 	mddev_t *mddev = container_of(kobj, struct mddev_s, kobj);
3405 	ssize_t rv;
3406 
3407 	if (!entry->store)
3408 		return -EIO;
3409 	if (!capable(CAP_SYS_ADMIN))
3410 		return -EACCES;
3411 	rv = mddev_lock(mddev);
3412 	if (!rv) {
3413 		rv = entry->store(mddev, page, length);
3414 		mddev_unlock(mddev);
3415 	}
3416 	return rv;
3417 }
3418 
3419 static void md_free(struct kobject *ko)
3420 {
3421 	mddev_t *mddev = container_of(ko, mddev_t, kobj);
3422 	kfree(mddev);
3423 }
3424 
3425 static struct sysfs_ops md_sysfs_ops = {
3426 	.show	= md_attr_show,
3427 	.store	= md_attr_store,
3428 };
3429 static struct kobj_type md_ktype = {
3430 	.release	= md_free,
3431 	.sysfs_ops	= &md_sysfs_ops,
3432 	.default_attrs	= md_default_attrs,
3433 };
3434 
3435 int mdp_major = 0;
3436 
3437 static struct kobject *md_probe(dev_t dev, int *part, void *data)
3438 {
3439 	static DEFINE_MUTEX(disks_mutex);
3440 	mddev_t *mddev = mddev_find(dev);
3441 	struct gendisk *disk;
3442 	int partitioned = (MAJOR(dev) != MD_MAJOR);
3443 	int shift = partitioned ? MdpMinorShift : 0;
3444 	int unit = MINOR(dev) >> shift;
3445 	int error;
3446 
3447 	if (!mddev)
3448 		return NULL;
3449 
3450 	mutex_lock(&disks_mutex);
3451 	if (mddev->gendisk) {
3452 		mutex_unlock(&disks_mutex);
3453 		mddev_put(mddev);
3454 		return NULL;
3455 	}
3456 	disk = alloc_disk(1 << shift);
3457 	if (!disk) {
3458 		mutex_unlock(&disks_mutex);
3459 		mddev_put(mddev);
3460 		return NULL;
3461 	}
3462 	disk->major = MAJOR(dev);
3463 	disk->first_minor = unit << shift;
3464 	if (partitioned)
3465 		sprintf(disk->disk_name, "md_d%d", unit);
3466 	else
3467 		sprintf(disk->disk_name, "md%d", unit);
3468 	disk->fops = &md_fops;
3469 	disk->private_data = mddev;
3470 	disk->queue = mddev->queue;
3471 	add_disk(disk);
3472 	mddev->gendisk = disk;
3473 	error = kobject_init_and_add(&mddev->kobj, &md_ktype, &disk->dev.kobj,
3474 				     "%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 	return NULL;
3482 }
3483 
3484 static void md_safemode_timeout(unsigned long data)
3485 {
3486 	mddev_t *mddev = (mddev_t *) data;
3487 
3488 	if (!atomic_read(&mddev->writes_pending)) {
3489 		mddev->safemode = 1;
3490 		if (mddev->external)
3491 			set_bit(MD_NOTIFY_ARRAY_STATE, &mddev->flags);
3492 	}
3493 	md_wakeup_thread(mddev->thread);
3494 }
3495 
3496 static int start_dirty_degraded;
3497 
3498 static int do_md_run(mddev_t * mddev)
3499 {
3500 	int err;
3501 	int chunk_size;
3502 	struct list_head *tmp;
3503 	mdk_rdev_t *rdev;
3504 	struct gendisk *disk;
3505 	struct mdk_personality *pers;
3506 	char b[BDEVNAME_SIZE];
3507 
3508 	if (list_empty(&mddev->disks))
3509 		/* cannot run an array with no devices.. */
3510 		return -EINVAL;
3511 
3512 	if (mddev->pers)
3513 		return -EBUSY;
3514 
3515 	/*
3516 	 * Analyze all RAID superblock(s)
3517 	 */
3518 	if (!mddev->raid_disks) {
3519 		if (!mddev->persistent)
3520 			return -EINVAL;
3521 		analyze_sbs(mddev);
3522 	}
3523 
3524 	chunk_size = mddev->chunk_size;
3525 
3526 	if (chunk_size) {
3527 		if (chunk_size > MAX_CHUNK_SIZE) {
3528 			printk(KERN_ERR "too big chunk_size: %d > %d\n",
3529 				chunk_size, MAX_CHUNK_SIZE);
3530 			return -EINVAL;
3531 		}
3532 		/*
3533 		 * chunk-size has to be a power of 2 and multiples of PAGE_SIZE
3534 		 */
3535 		if ( (1 << ffz(~chunk_size)) != chunk_size) {
3536 			printk(KERN_ERR "chunk_size of %d not valid\n", chunk_size);
3537 			return -EINVAL;
3538 		}
3539 		if (chunk_size < PAGE_SIZE) {
3540 			printk(KERN_ERR "too small chunk_size: %d < %ld\n",
3541 				chunk_size, PAGE_SIZE);
3542 			return -EINVAL;
3543 		}
3544 
3545 		/* devices must have minimum size of one chunk */
3546 		rdev_for_each(rdev, tmp, mddev) {
3547 			if (test_bit(Faulty, &rdev->flags))
3548 				continue;
3549 			if (rdev->size < chunk_size / 1024) {
3550 				printk(KERN_WARNING
3551 					"md: Dev %s smaller than chunk_size:"
3552 					" %lluk < %dk\n",
3553 					bdevname(rdev->bdev,b),
3554 					(unsigned long long)rdev->size,
3555 					chunk_size / 1024);
3556 				return -EINVAL;
3557 			}
3558 		}
3559 	}
3560 
3561 #ifdef CONFIG_KMOD
3562 	if (mddev->level != LEVEL_NONE)
3563 		request_module("md-level-%d", mddev->level);
3564 	else if (mddev->clevel[0])
3565 		request_module("md-%s", mddev->clevel);
3566 #endif
3567 
3568 	/*
3569 	 * Drop all container device buffers, from now on
3570 	 * the only valid external interface is through the md
3571 	 * device.
3572 	 */
3573 	rdev_for_each(rdev, tmp, mddev) {
3574 		if (test_bit(Faulty, &rdev->flags))
3575 			continue;
3576 		sync_blockdev(rdev->bdev);
3577 		invalidate_bdev(rdev->bdev);
3578 
3579 		/* perform some consistency tests on the device.
3580 		 * We don't want the data to overlap the metadata,
3581 		 * Internal Bitmap issues has handled elsewhere.
3582 		 */
3583 		if (rdev->data_offset < rdev->sb_start) {
3584 			if (mddev->size &&
3585 			    rdev->data_offset + mddev->size*2
3586 			    > rdev->sb_start) {
3587 				printk("md: %s: data overlaps metadata\n",
3588 				       mdname(mddev));
3589 				return -EINVAL;
3590 			}
3591 		} else {
3592 			if (rdev->sb_start + rdev->sb_size/512
3593 			    > rdev->data_offset) {
3594 				printk("md: %s: metadata overlaps data\n",
3595 				       mdname(mddev));
3596 				return -EINVAL;
3597 			}
3598 		}
3599 		sysfs_notify(&rdev->kobj, NULL, "state");
3600 	}
3601 
3602 	md_probe(mddev->unit, NULL, NULL);
3603 	disk = mddev->gendisk;
3604 	if (!disk)
3605 		return -ENOMEM;
3606 
3607 	spin_lock(&pers_lock);
3608 	pers = find_pers(mddev->level, mddev->clevel);
3609 	if (!pers || !try_module_get(pers->owner)) {
3610 		spin_unlock(&pers_lock);
3611 		if (mddev->level != LEVEL_NONE)
3612 			printk(KERN_WARNING "md: personality for level %d is not loaded!\n",
3613 			       mddev->level);
3614 		else
3615 			printk(KERN_WARNING "md: personality for level %s is not loaded!\n",
3616 			       mddev->clevel);
3617 		return -EINVAL;
3618 	}
3619 	mddev->pers = pers;
3620 	spin_unlock(&pers_lock);
3621 	mddev->level = pers->level;
3622 	strlcpy(mddev->clevel, pers->name, sizeof(mddev->clevel));
3623 
3624 	if (mddev->reshape_position != MaxSector &&
3625 	    pers->start_reshape == NULL) {
3626 		/* This personality cannot handle reshaping... */
3627 		mddev->pers = NULL;
3628 		module_put(pers->owner);
3629 		return -EINVAL;
3630 	}
3631 
3632 	if (pers->sync_request) {
3633 		/* Warn if this is a potentially silly
3634 		 * configuration.
3635 		 */
3636 		char b[BDEVNAME_SIZE], b2[BDEVNAME_SIZE];
3637 		mdk_rdev_t *rdev2;
3638 		struct list_head *tmp2;
3639 		int warned = 0;
3640 		rdev_for_each(rdev, tmp, mddev) {
3641 			rdev_for_each(rdev2, tmp2, mddev) {
3642 				if (rdev < rdev2 &&
3643 				    rdev->bdev->bd_contains ==
3644 				    rdev2->bdev->bd_contains) {
3645 					printk(KERN_WARNING
3646 					       "%s: WARNING: %s appears to be"
3647 					       " on the same physical disk as"
3648 					       " %s.\n",
3649 					       mdname(mddev),
3650 					       bdevname(rdev->bdev,b),
3651 					       bdevname(rdev2->bdev,b2));
3652 					warned = 1;
3653 				}
3654 			}
3655 		}
3656 		if (warned)
3657 			printk(KERN_WARNING
3658 			       "True protection against single-disk"
3659 			       " failure might be compromised.\n");
3660 	}
3661 
3662 	mddev->recovery = 0;
3663 	mddev->resync_max_sectors = mddev->size << 1; /* may be over-ridden by personality */
3664 	mddev->barriers_work = 1;
3665 	mddev->ok_start_degraded = start_dirty_degraded;
3666 
3667 	if (start_readonly)
3668 		mddev->ro = 2; /* read-only, but switch on first write */
3669 
3670 	err = mddev->pers->run(mddev);
3671 	if (err)
3672 		printk(KERN_ERR "md: pers->run() failed ...\n");
3673 	else if (mddev->pers->sync_request) {
3674 		err = bitmap_create(mddev);
3675 		if (err) {
3676 			printk(KERN_ERR "%s: failed to create bitmap (%d)\n",
3677 			       mdname(mddev), err);
3678 			mddev->pers->stop(mddev);
3679 		}
3680 	}
3681 	if (err) {
3682 		module_put(mddev->pers->owner);
3683 		mddev->pers = NULL;
3684 		bitmap_destroy(mddev);
3685 		return err;
3686 	}
3687 	if (mddev->pers->sync_request) {
3688 		if (sysfs_create_group(&mddev->kobj, &md_redundancy_group))
3689 			printk(KERN_WARNING
3690 			       "md: cannot register extra attributes for %s\n",
3691 			       mdname(mddev));
3692 	} else if (mddev->ro == 2) /* auto-readonly not meaningful */
3693 		mddev->ro = 0;
3694 
3695  	atomic_set(&mddev->writes_pending,0);
3696 	mddev->safemode = 0;
3697 	mddev->safemode_timer.function = md_safemode_timeout;
3698 	mddev->safemode_timer.data = (unsigned long) mddev;
3699 	mddev->safemode_delay = (200 * HZ)/1000 +1; /* 200 msec delay */
3700 	mddev->in_sync = 1;
3701 
3702 	rdev_for_each(rdev, tmp, mddev)
3703 		if (rdev->raid_disk >= 0) {
3704 			char nm[20];
3705 			sprintf(nm, "rd%d", rdev->raid_disk);
3706 			if (sysfs_create_link(&mddev->kobj, &rdev->kobj, nm))
3707 				printk("md: cannot register %s for %s\n",
3708 				       nm, mdname(mddev));
3709 		}
3710 
3711 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
3712 
3713 	if (mddev->flags)
3714 		md_update_sb(mddev, 0);
3715 
3716 	set_capacity(disk, mddev->array_sectors);
3717 
3718 	/* If we call blk_queue_make_request here, it will
3719 	 * re-initialise max_sectors etc which may have been
3720 	 * refined inside -> run.  So just set the bits we need to set.
3721 	 * Most initialisation happended when we called
3722 	 * blk_queue_make_request(..., md_fail_request)
3723 	 * earlier.
3724 	 */
3725 	mddev->queue->queuedata = mddev;
3726 	mddev->queue->make_request_fn = mddev->pers->make_request;
3727 
3728 	/* If there is a partially-recovered drive we need to
3729 	 * start recovery here.  If we leave it to md_check_recovery,
3730 	 * it will remove the drives and not do the right thing
3731 	 */
3732 	if (mddev->degraded && !mddev->sync_thread) {
3733 		struct list_head *rtmp;
3734 		int spares = 0;
3735 		rdev_for_each(rdev, rtmp, mddev)
3736 			if (rdev->raid_disk >= 0 &&
3737 			    !test_bit(In_sync, &rdev->flags) &&
3738 			    !test_bit(Faulty, &rdev->flags))
3739 				/* complete an interrupted recovery */
3740 				spares++;
3741 		if (spares && mddev->pers->sync_request) {
3742 			mddev->recovery = 0;
3743 			set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
3744 			mddev->sync_thread = md_register_thread(md_do_sync,
3745 								mddev,
3746 								"%s_resync");
3747 			if (!mddev->sync_thread) {
3748 				printk(KERN_ERR "%s: could not start resync"
3749 				       " thread...\n",
3750 				       mdname(mddev));
3751 				/* leave the spares where they are, it shouldn't hurt */
3752 				mddev->recovery = 0;
3753 			}
3754 		}
3755 	}
3756 	md_wakeup_thread(mddev->thread);
3757 	md_wakeup_thread(mddev->sync_thread); /* possibly kick off a reshape */
3758 
3759 	mddev->changed = 1;
3760 	md_new_event(mddev);
3761 	sysfs_notify(&mddev->kobj, NULL, "array_state");
3762 	sysfs_notify(&mddev->kobj, NULL, "sync_action");
3763 	sysfs_notify(&mddev->kobj, NULL, "degraded");
3764 	kobject_uevent(&mddev->gendisk->dev.kobj, KOBJ_CHANGE);
3765 	return 0;
3766 }
3767 
3768 static int restart_array(mddev_t *mddev)
3769 {
3770 	struct gendisk *disk = mddev->gendisk;
3771 
3772 	/* Complain if it has no devices */
3773 	if (list_empty(&mddev->disks))
3774 		return -ENXIO;
3775 	if (!mddev->pers)
3776 		return -EINVAL;
3777 	if (!mddev->ro)
3778 		return -EBUSY;
3779 	mddev->safemode = 0;
3780 	mddev->ro = 0;
3781 	set_disk_ro(disk, 0);
3782 	printk(KERN_INFO "md: %s switched to read-write mode.\n",
3783 		mdname(mddev));
3784 	/* Kick recovery or resync if necessary */
3785 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
3786 	md_wakeup_thread(mddev->thread);
3787 	md_wakeup_thread(mddev->sync_thread);
3788 	sysfs_notify(&mddev->kobj, NULL, "array_state");
3789 	return 0;
3790 }
3791 
3792 /* similar to deny_write_access, but accounts for our holding a reference
3793  * to the file ourselves */
3794 static int deny_bitmap_write_access(struct file * file)
3795 {
3796 	struct inode *inode = file->f_mapping->host;
3797 
3798 	spin_lock(&inode->i_lock);
3799 	if (atomic_read(&inode->i_writecount) > 1) {
3800 		spin_unlock(&inode->i_lock);
3801 		return -ETXTBSY;
3802 	}
3803 	atomic_set(&inode->i_writecount, -1);
3804 	spin_unlock(&inode->i_lock);
3805 
3806 	return 0;
3807 }
3808 
3809 static void restore_bitmap_write_access(struct file *file)
3810 {
3811 	struct inode *inode = file->f_mapping->host;
3812 
3813 	spin_lock(&inode->i_lock);
3814 	atomic_set(&inode->i_writecount, 1);
3815 	spin_unlock(&inode->i_lock);
3816 }
3817 
3818 /* mode:
3819  *   0 - completely stop and dis-assemble array
3820  *   1 - switch to readonly
3821  *   2 - stop but do not disassemble array
3822  */
3823 static int do_md_stop(mddev_t * mddev, int mode, int is_open)
3824 {
3825 	int err = 0;
3826 	struct gendisk *disk = mddev->gendisk;
3827 
3828 	if (atomic_read(&mddev->openers) > is_open) {
3829 		printk("md: %s still in use.\n",mdname(mddev));
3830 		return -EBUSY;
3831 	}
3832 
3833 	if (mddev->pers) {
3834 
3835 		if (mddev->sync_thread) {
3836 			set_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
3837 			set_bit(MD_RECOVERY_INTR, &mddev->recovery);
3838 			md_unregister_thread(mddev->sync_thread);
3839 			mddev->sync_thread = NULL;
3840 		}
3841 
3842 		del_timer_sync(&mddev->safemode_timer);
3843 
3844 		switch(mode) {
3845 		case 1: /* readonly */
3846 			err  = -ENXIO;
3847 			if (mddev->ro==1)
3848 				goto out;
3849 			mddev->ro = 1;
3850 			break;
3851 		case 0: /* disassemble */
3852 		case 2: /* stop */
3853 			bitmap_flush(mddev);
3854 			md_super_wait(mddev);
3855 			if (mddev->ro)
3856 				set_disk_ro(disk, 0);
3857 			blk_queue_make_request(mddev->queue, md_fail_request);
3858 			mddev->pers->stop(mddev);
3859 			mddev->queue->merge_bvec_fn = NULL;
3860 			mddev->queue->unplug_fn = NULL;
3861 			mddev->queue->backing_dev_info.congested_fn = NULL;
3862 			if (mddev->pers->sync_request)
3863 				sysfs_remove_group(&mddev->kobj, &md_redundancy_group);
3864 
3865 			module_put(mddev->pers->owner);
3866 			mddev->pers = NULL;
3867 			/* tell userspace to handle 'inactive' */
3868 			sysfs_notify(&mddev->kobj, NULL, "array_state");
3869 
3870 			set_capacity(disk, 0);
3871 			mddev->changed = 1;
3872 
3873 			if (mddev->ro)
3874 				mddev->ro = 0;
3875 		}
3876 		if (!mddev->in_sync || mddev->flags) {
3877 			/* mark array as shutdown cleanly */
3878 			mddev->in_sync = 1;
3879 			md_update_sb(mddev, 1);
3880 		}
3881 		if (mode == 1)
3882 			set_disk_ro(disk, 1);
3883 		clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
3884 	}
3885 
3886 	/*
3887 	 * Free resources if final stop
3888 	 */
3889 	if (mode == 0) {
3890 		mdk_rdev_t *rdev;
3891 		struct list_head *tmp;
3892 
3893 		printk(KERN_INFO "md: %s stopped.\n", mdname(mddev));
3894 
3895 		bitmap_destroy(mddev);
3896 		if (mddev->bitmap_file) {
3897 			restore_bitmap_write_access(mddev->bitmap_file);
3898 			fput(mddev->bitmap_file);
3899 			mddev->bitmap_file = NULL;
3900 		}
3901 		mddev->bitmap_offset = 0;
3902 
3903 		rdev_for_each(rdev, tmp, mddev)
3904 			if (rdev->raid_disk >= 0) {
3905 				char nm[20];
3906 				sprintf(nm, "rd%d", rdev->raid_disk);
3907 				sysfs_remove_link(&mddev->kobj, nm);
3908 			}
3909 
3910 		/* make sure all md_delayed_delete calls have finished */
3911 		flush_scheduled_work();
3912 
3913 		export_array(mddev);
3914 
3915 		mddev->array_sectors = 0;
3916 		mddev->size = 0;
3917 		mddev->raid_disks = 0;
3918 		mddev->recovery_cp = 0;
3919 		mddev->resync_min = 0;
3920 		mddev->resync_max = MaxSector;
3921 		mddev->reshape_position = MaxSector;
3922 		mddev->external = 0;
3923 		mddev->persistent = 0;
3924 		mddev->level = LEVEL_NONE;
3925 		mddev->clevel[0] = 0;
3926 		mddev->flags = 0;
3927 		mddev->ro = 0;
3928 		mddev->metadata_type[0] = 0;
3929 		mddev->chunk_size = 0;
3930 		mddev->ctime = mddev->utime = 0;
3931 		mddev->layout = 0;
3932 		mddev->max_disks = 0;
3933 		mddev->events = 0;
3934 		mddev->delta_disks = 0;
3935 		mddev->new_level = LEVEL_NONE;
3936 		mddev->new_layout = 0;
3937 		mddev->new_chunk = 0;
3938 		mddev->curr_resync = 0;
3939 		mddev->resync_mismatches = 0;
3940 		mddev->suspend_lo = mddev->suspend_hi = 0;
3941 		mddev->sync_speed_min = mddev->sync_speed_max = 0;
3942 		mddev->recovery = 0;
3943 		mddev->in_sync = 0;
3944 		mddev->changed = 0;
3945 		mddev->degraded = 0;
3946 		mddev->barriers_work = 0;
3947 		mddev->safemode = 0;
3948 
3949 	} else if (mddev->pers)
3950 		printk(KERN_INFO "md: %s switched to read-only mode.\n",
3951 			mdname(mddev));
3952 	err = 0;
3953 	md_new_event(mddev);
3954 	sysfs_notify(&mddev->kobj, NULL, "array_state");
3955 out:
3956 	return err;
3957 }
3958 
3959 #ifndef MODULE
3960 static void autorun_array(mddev_t *mddev)
3961 {
3962 	mdk_rdev_t *rdev;
3963 	struct list_head *tmp;
3964 	int err;
3965 
3966 	if (list_empty(&mddev->disks))
3967 		return;
3968 
3969 	printk(KERN_INFO "md: running: ");
3970 
3971 	rdev_for_each(rdev, tmp, mddev) {
3972 		char b[BDEVNAME_SIZE];
3973 		printk("<%s>", bdevname(rdev->bdev,b));
3974 	}
3975 	printk("\n");
3976 
3977 	err = do_md_run (mddev);
3978 	if (err) {
3979 		printk(KERN_WARNING "md: do_md_run() returned %d\n", err);
3980 		do_md_stop (mddev, 0, 0);
3981 	}
3982 }
3983 
3984 /*
3985  * lets try to run arrays based on all disks that have arrived
3986  * until now. (those are in pending_raid_disks)
3987  *
3988  * the method: pick the first pending disk, collect all disks with
3989  * the same UUID, remove all from the pending list and put them into
3990  * the 'same_array' list. Then order this list based on superblock
3991  * update time (freshest comes first), kick out 'old' disks and
3992  * compare superblocks. If everything's fine then run it.
3993  *
3994  * If "unit" is allocated, then bump its reference count
3995  */
3996 static void autorun_devices(int part)
3997 {
3998 	struct list_head *tmp;
3999 	mdk_rdev_t *rdev0, *rdev;
4000 	mddev_t *mddev;
4001 	char b[BDEVNAME_SIZE];
4002 
4003 	printk(KERN_INFO "md: autorun ...\n");
4004 	while (!list_empty(&pending_raid_disks)) {
4005 		int unit;
4006 		dev_t dev;
4007 		LIST_HEAD(candidates);
4008 		rdev0 = list_entry(pending_raid_disks.next,
4009 					 mdk_rdev_t, same_set);
4010 
4011 		printk(KERN_INFO "md: considering %s ...\n",
4012 			bdevname(rdev0->bdev,b));
4013 		INIT_LIST_HEAD(&candidates);
4014 		rdev_for_each_list(rdev, tmp, pending_raid_disks)
4015 			if (super_90_load(rdev, rdev0, 0) >= 0) {
4016 				printk(KERN_INFO "md:  adding %s ...\n",
4017 					bdevname(rdev->bdev,b));
4018 				list_move(&rdev->same_set, &candidates);
4019 			}
4020 		/*
4021 		 * now we have a set of devices, with all of them having
4022 		 * mostly sane superblocks. It's time to allocate the
4023 		 * mddev.
4024 		 */
4025 		if (part) {
4026 			dev = MKDEV(mdp_major,
4027 				    rdev0->preferred_minor << MdpMinorShift);
4028 			unit = MINOR(dev) >> MdpMinorShift;
4029 		} else {
4030 			dev = MKDEV(MD_MAJOR, rdev0->preferred_minor);
4031 			unit = MINOR(dev);
4032 		}
4033 		if (rdev0->preferred_minor != unit) {
4034 			printk(KERN_INFO "md: unit number in %s is bad: %d\n",
4035 			       bdevname(rdev0->bdev, b), rdev0->preferred_minor);
4036 			break;
4037 		}
4038 
4039 		md_probe(dev, NULL, NULL);
4040 		mddev = mddev_find(dev);
4041 		if (!mddev || !mddev->gendisk) {
4042 			if (mddev)
4043 				mddev_put(mddev);
4044 			printk(KERN_ERR
4045 				"md: cannot allocate memory for md drive.\n");
4046 			break;
4047 		}
4048 		if (mddev_lock(mddev))
4049 			printk(KERN_WARNING "md: %s locked, cannot run\n",
4050 			       mdname(mddev));
4051 		else if (mddev->raid_disks || mddev->major_version
4052 			 || !list_empty(&mddev->disks)) {
4053 			printk(KERN_WARNING
4054 				"md: %s already running, cannot run %s\n",
4055 				mdname(mddev), bdevname(rdev0->bdev,b));
4056 			mddev_unlock(mddev);
4057 		} else {
4058 			printk(KERN_INFO "md: created %s\n", mdname(mddev));
4059 			mddev->persistent = 1;
4060 			rdev_for_each_list(rdev, tmp, candidates) {
4061 				list_del_init(&rdev->same_set);
4062 				if (bind_rdev_to_array(rdev, mddev))
4063 					export_rdev(rdev);
4064 			}
4065 			autorun_array(mddev);
4066 			mddev_unlock(mddev);
4067 		}
4068 		/* on success, candidates will be empty, on error
4069 		 * it won't...
4070 		 */
4071 		rdev_for_each_list(rdev, tmp, candidates) {
4072 			list_del_init(&rdev->same_set);
4073 			export_rdev(rdev);
4074 		}
4075 		mddev_put(mddev);
4076 	}
4077 	printk(KERN_INFO "md: ... autorun DONE.\n");
4078 }
4079 #endif /* !MODULE */
4080 
4081 static int get_version(void __user * arg)
4082 {
4083 	mdu_version_t ver;
4084 
4085 	ver.major = MD_MAJOR_VERSION;
4086 	ver.minor = MD_MINOR_VERSION;
4087 	ver.patchlevel = MD_PATCHLEVEL_VERSION;
4088 
4089 	if (copy_to_user(arg, &ver, sizeof(ver)))
4090 		return -EFAULT;
4091 
4092 	return 0;
4093 }
4094 
4095 static int get_array_info(mddev_t * mddev, void __user * arg)
4096 {
4097 	mdu_array_info_t info;
4098 	int nr,working,active,failed,spare;
4099 	mdk_rdev_t *rdev;
4100 	struct list_head *tmp;
4101 
4102 	nr=working=active=failed=spare=0;
4103 	rdev_for_each(rdev, tmp, mddev) {
4104 		nr++;
4105 		if (test_bit(Faulty, &rdev->flags))
4106 			failed++;
4107 		else {
4108 			working++;
4109 			if (test_bit(In_sync, &rdev->flags))
4110 				active++;
4111 			else
4112 				spare++;
4113 		}
4114 	}
4115 
4116 	info.major_version = mddev->major_version;
4117 	info.minor_version = mddev->minor_version;
4118 	info.patch_version = MD_PATCHLEVEL_VERSION;
4119 	info.ctime         = mddev->ctime;
4120 	info.level         = mddev->level;
4121 	info.size          = mddev->size;
4122 	if (info.size != mddev->size) /* overflow */
4123 		info.size = -1;
4124 	info.nr_disks      = nr;
4125 	info.raid_disks    = mddev->raid_disks;
4126 	info.md_minor      = mddev->md_minor;
4127 	info.not_persistent= !mddev->persistent;
4128 
4129 	info.utime         = mddev->utime;
4130 	info.state         = 0;
4131 	if (mddev->in_sync)
4132 		info.state = (1<<MD_SB_CLEAN);
4133 	if (mddev->bitmap && mddev->bitmap_offset)
4134 		info.state = (1<<MD_SB_BITMAP_PRESENT);
4135 	info.active_disks  = active;
4136 	info.working_disks = working;
4137 	info.failed_disks  = failed;
4138 	info.spare_disks   = spare;
4139 
4140 	info.layout        = mddev->layout;
4141 	info.chunk_size    = mddev->chunk_size;
4142 
4143 	if (copy_to_user(arg, &info, sizeof(info)))
4144 		return -EFAULT;
4145 
4146 	return 0;
4147 }
4148 
4149 static int get_bitmap_file(mddev_t * mddev, void __user * arg)
4150 {
4151 	mdu_bitmap_file_t *file = NULL; /* too big for stack allocation */
4152 	char *ptr, *buf = NULL;
4153 	int err = -ENOMEM;
4154 
4155 	if (md_allow_write(mddev))
4156 		file = kmalloc(sizeof(*file), GFP_NOIO);
4157 	else
4158 		file = kmalloc(sizeof(*file), GFP_KERNEL);
4159 
4160 	if (!file)
4161 		goto out;
4162 
4163 	/* bitmap disabled, zero the first byte and copy out */
4164 	if (!mddev->bitmap || !mddev->bitmap->file) {
4165 		file->pathname[0] = '\0';
4166 		goto copy_out;
4167 	}
4168 
4169 	buf = kmalloc(sizeof(file->pathname), GFP_KERNEL);
4170 	if (!buf)
4171 		goto out;
4172 
4173 	ptr = d_path(&mddev->bitmap->file->f_path, buf, sizeof(file->pathname));
4174 	if (IS_ERR(ptr))
4175 		goto out;
4176 
4177 	strcpy(file->pathname, ptr);
4178 
4179 copy_out:
4180 	err = 0;
4181 	if (copy_to_user(arg, file, sizeof(*file)))
4182 		err = -EFAULT;
4183 out:
4184 	kfree(buf);
4185 	kfree(file);
4186 	return err;
4187 }
4188 
4189 static int get_disk_info(mddev_t * mddev, void __user * arg)
4190 {
4191 	mdu_disk_info_t info;
4192 	mdk_rdev_t *rdev;
4193 
4194 	if (copy_from_user(&info, arg, sizeof(info)))
4195 		return -EFAULT;
4196 
4197 	rdev = find_rdev_nr(mddev, info.number);
4198 	if (rdev) {
4199 		info.major = MAJOR(rdev->bdev->bd_dev);
4200 		info.minor = MINOR(rdev->bdev->bd_dev);
4201 		info.raid_disk = rdev->raid_disk;
4202 		info.state = 0;
4203 		if (test_bit(Faulty, &rdev->flags))
4204 			info.state |= (1<<MD_DISK_FAULTY);
4205 		else if (test_bit(In_sync, &rdev->flags)) {
4206 			info.state |= (1<<MD_DISK_ACTIVE);
4207 			info.state |= (1<<MD_DISK_SYNC);
4208 		}
4209 		if (test_bit(WriteMostly, &rdev->flags))
4210 			info.state |= (1<<MD_DISK_WRITEMOSTLY);
4211 	} else {
4212 		info.major = info.minor = 0;
4213 		info.raid_disk = -1;
4214 		info.state = (1<<MD_DISK_REMOVED);
4215 	}
4216 
4217 	if (copy_to_user(arg, &info, sizeof(info)))
4218 		return -EFAULT;
4219 
4220 	return 0;
4221 }
4222 
4223 static int add_new_disk(mddev_t * mddev, mdu_disk_info_t *info)
4224 {
4225 	char b[BDEVNAME_SIZE], b2[BDEVNAME_SIZE];
4226 	mdk_rdev_t *rdev;
4227 	dev_t dev = MKDEV(info->major,info->minor);
4228 
4229 	if (info->major != MAJOR(dev) || info->minor != MINOR(dev))
4230 		return -EOVERFLOW;
4231 
4232 	if (!mddev->raid_disks) {
4233 		int err;
4234 		/* expecting a device which has a superblock */
4235 		rdev = md_import_device(dev, mddev->major_version, mddev->minor_version);
4236 		if (IS_ERR(rdev)) {
4237 			printk(KERN_WARNING
4238 				"md: md_import_device returned %ld\n",
4239 				PTR_ERR(rdev));
4240 			return PTR_ERR(rdev);
4241 		}
4242 		if (!list_empty(&mddev->disks)) {
4243 			mdk_rdev_t *rdev0 = list_entry(mddev->disks.next,
4244 							mdk_rdev_t, same_set);
4245 			int err = super_types[mddev->major_version]
4246 				.load_super(rdev, rdev0, mddev->minor_version);
4247 			if (err < 0) {
4248 				printk(KERN_WARNING
4249 					"md: %s has different UUID to %s\n",
4250 					bdevname(rdev->bdev,b),
4251 					bdevname(rdev0->bdev,b2));
4252 				export_rdev(rdev);
4253 				return -EINVAL;
4254 			}
4255 		}
4256 		err = bind_rdev_to_array(rdev, mddev);
4257 		if (err)
4258 			export_rdev(rdev);
4259 		return err;
4260 	}
4261 
4262 	/*
4263 	 * add_new_disk can be used once the array is assembled
4264 	 * to add "hot spares".  They must already have a superblock
4265 	 * written
4266 	 */
4267 	if (mddev->pers) {
4268 		int err;
4269 		if (!mddev->pers->hot_add_disk) {
4270 			printk(KERN_WARNING
4271 				"%s: personality does not support diskops!\n",
4272 			       mdname(mddev));
4273 			return -EINVAL;
4274 		}
4275 		if (mddev->persistent)
4276 			rdev = md_import_device(dev, mddev->major_version,
4277 						mddev->minor_version);
4278 		else
4279 			rdev = md_import_device(dev, -1, -1);
4280 		if (IS_ERR(rdev)) {
4281 			printk(KERN_WARNING
4282 				"md: md_import_device returned %ld\n",
4283 				PTR_ERR(rdev));
4284 			return PTR_ERR(rdev);
4285 		}
4286 		/* set save_raid_disk if appropriate */
4287 		if (!mddev->persistent) {
4288 			if (info->state & (1<<MD_DISK_SYNC)  &&
4289 			    info->raid_disk < mddev->raid_disks)
4290 				rdev->raid_disk = info->raid_disk;
4291 			else
4292 				rdev->raid_disk = -1;
4293 		} else
4294 			super_types[mddev->major_version].
4295 				validate_super(mddev, rdev);
4296 		rdev->saved_raid_disk = rdev->raid_disk;
4297 
4298 		clear_bit(In_sync, &rdev->flags); /* just to be sure */
4299 		if (info->state & (1<<MD_DISK_WRITEMOSTLY))
4300 			set_bit(WriteMostly, &rdev->flags);
4301 
4302 		rdev->raid_disk = -1;
4303 		err = bind_rdev_to_array(rdev, mddev);
4304 		if (!err && !mddev->pers->hot_remove_disk) {
4305 			/* If there is hot_add_disk but no hot_remove_disk
4306 			 * then added disks for geometry changes,
4307 			 * and should be added immediately.
4308 			 */
4309 			super_types[mddev->major_version].
4310 				validate_super(mddev, rdev);
4311 			err = mddev->pers->hot_add_disk(mddev, rdev);
4312 			if (err)
4313 				unbind_rdev_from_array(rdev);
4314 		}
4315 		if (err)
4316 			export_rdev(rdev);
4317 		else
4318 			sysfs_notify(&rdev->kobj, NULL, "state");
4319 
4320 		md_update_sb(mddev, 1);
4321 		if (mddev->degraded)
4322 			set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
4323 		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
4324 		md_wakeup_thread(mddev->thread);
4325 		return err;
4326 	}
4327 
4328 	/* otherwise, add_new_disk is only allowed
4329 	 * for major_version==0 superblocks
4330 	 */
4331 	if (mddev->major_version != 0) {
4332 		printk(KERN_WARNING "%s: ADD_NEW_DISK not supported\n",
4333 		       mdname(mddev));
4334 		return -EINVAL;
4335 	}
4336 
4337 	if (!(info->state & (1<<MD_DISK_FAULTY))) {
4338 		int err;
4339 		rdev = md_import_device (dev, -1, 0);
4340 		if (IS_ERR(rdev)) {
4341 			printk(KERN_WARNING
4342 				"md: error, md_import_device() returned %ld\n",
4343 				PTR_ERR(rdev));
4344 			return PTR_ERR(rdev);
4345 		}
4346 		rdev->desc_nr = info->number;
4347 		if (info->raid_disk < mddev->raid_disks)
4348 			rdev->raid_disk = info->raid_disk;
4349 		else
4350 			rdev->raid_disk = -1;
4351 
4352 		if (rdev->raid_disk < mddev->raid_disks)
4353 			if (info->state & (1<<MD_DISK_SYNC))
4354 				set_bit(In_sync, &rdev->flags);
4355 
4356 		if (info->state & (1<<MD_DISK_WRITEMOSTLY))
4357 			set_bit(WriteMostly, &rdev->flags);
4358 
4359 		if (!mddev->persistent) {
4360 			printk(KERN_INFO "md: nonpersistent superblock ...\n");
4361 			rdev->sb_start = rdev->bdev->bd_inode->i_size / 512;
4362 		} else
4363 			rdev->sb_start = calc_dev_sboffset(rdev->bdev);
4364 		rdev->size = calc_num_sectors(rdev, mddev->chunk_size) / 2;
4365 
4366 		err = bind_rdev_to_array(rdev, mddev);
4367 		if (err) {
4368 			export_rdev(rdev);
4369 			return err;
4370 		}
4371 	}
4372 
4373 	return 0;
4374 }
4375 
4376 static int hot_remove_disk(mddev_t * mddev, dev_t dev)
4377 {
4378 	char b[BDEVNAME_SIZE];
4379 	mdk_rdev_t *rdev;
4380 
4381 	rdev = find_rdev(mddev, dev);
4382 	if (!rdev)
4383 		return -ENXIO;
4384 
4385 	if (rdev->raid_disk >= 0)
4386 		goto busy;
4387 
4388 	kick_rdev_from_array(rdev);
4389 	md_update_sb(mddev, 1);
4390 	md_new_event(mddev);
4391 
4392 	return 0;
4393 busy:
4394 	printk(KERN_WARNING "md: cannot remove active disk %s from %s ...\n",
4395 		bdevname(rdev->bdev,b), mdname(mddev));
4396 	return -EBUSY;
4397 }
4398 
4399 static int hot_add_disk(mddev_t * mddev, dev_t dev)
4400 {
4401 	char b[BDEVNAME_SIZE];
4402 	int err;
4403 	mdk_rdev_t *rdev;
4404 
4405 	if (!mddev->pers)
4406 		return -ENODEV;
4407 
4408 	if (mddev->major_version != 0) {
4409 		printk(KERN_WARNING "%s: HOT_ADD may only be used with"
4410 			" version-0 superblocks.\n",
4411 			mdname(mddev));
4412 		return -EINVAL;
4413 	}
4414 	if (!mddev->pers->hot_add_disk) {
4415 		printk(KERN_WARNING
4416 			"%s: personality does not support diskops!\n",
4417 			mdname(mddev));
4418 		return -EINVAL;
4419 	}
4420 
4421 	rdev = md_import_device (dev, -1, 0);
4422 	if (IS_ERR(rdev)) {
4423 		printk(KERN_WARNING
4424 			"md: error, md_import_device() returned %ld\n",
4425 			PTR_ERR(rdev));
4426 		return -EINVAL;
4427 	}
4428 
4429 	if (mddev->persistent)
4430 		rdev->sb_start = calc_dev_sboffset(rdev->bdev);
4431 	else
4432 		rdev->sb_start = rdev->bdev->bd_inode->i_size / 512;
4433 
4434 	rdev->size = calc_num_sectors(rdev, mddev->chunk_size) / 2;
4435 
4436 	if (test_bit(Faulty, &rdev->flags)) {
4437 		printk(KERN_WARNING
4438 			"md: can not hot-add faulty %s disk to %s!\n",
4439 			bdevname(rdev->bdev,b), mdname(mddev));
4440 		err = -EINVAL;
4441 		goto abort_export;
4442 	}
4443 	clear_bit(In_sync, &rdev->flags);
4444 	rdev->desc_nr = -1;
4445 	rdev->saved_raid_disk = -1;
4446 	err = bind_rdev_to_array(rdev, mddev);
4447 	if (err)
4448 		goto abort_export;
4449 
4450 	/*
4451 	 * The rest should better be atomic, we can have disk failures
4452 	 * noticed in interrupt contexts ...
4453 	 */
4454 
4455 	if (rdev->desc_nr == mddev->max_disks) {
4456 		printk(KERN_WARNING "%s: can not hot-add to full array!\n",
4457 			mdname(mddev));
4458 		err = -EBUSY;
4459 		goto abort_unbind_export;
4460 	}
4461 
4462 	rdev->raid_disk = -1;
4463 
4464 	md_update_sb(mddev, 1);
4465 
4466 	/*
4467 	 * Kick recovery, maybe this spare has to be added to the
4468 	 * array immediately.
4469 	 */
4470 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
4471 	md_wakeup_thread(mddev->thread);
4472 	md_new_event(mddev);
4473 	return 0;
4474 
4475 abort_unbind_export:
4476 	unbind_rdev_from_array(rdev);
4477 
4478 abort_export:
4479 	export_rdev(rdev);
4480 	return err;
4481 }
4482 
4483 static int set_bitmap_file(mddev_t *mddev, int fd)
4484 {
4485 	int err;
4486 
4487 	if (mddev->pers) {
4488 		if (!mddev->pers->quiesce)
4489 			return -EBUSY;
4490 		if (mddev->recovery || mddev->sync_thread)
4491 			return -EBUSY;
4492 		/* we should be able to change the bitmap.. */
4493 	}
4494 
4495 
4496 	if (fd >= 0) {
4497 		if (mddev->bitmap)
4498 			return -EEXIST; /* cannot add when bitmap is present */
4499 		mddev->bitmap_file = fget(fd);
4500 
4501 		if (mddev->bitmap_file == NULL) {
4502 			printk(KERN_ERR "%s: error: failed to get bitmap file\n",
4503 			       mdname(mddev));
4504 			return -EBADF;
4505 		}
4506 
4507 		err = deny_bitmap_write_access(mddev->bitmap_file);
4508 		if (err) {
4509 			printk(KERN_ERR "%s: error: bitmap file is already in use\n",
4510 			       mdname(mddev));
4511 			fput(mddev->bitmap_file);
4512 			mddev->bitmap_file = NULL;
4513 			return err;
4514 		}
4515 		mddev->bitmap_offset = 0; /* file overrides offset */
4516 	} else if (mddev->bitmap == NULL)
4517 		return -ENOENT; /* cannot remove what isn't there */
4518 	err = 0;
4519 	if (mddev->pers) {
4520 		mddev->pers->quiesce(mddev, 1);
4521 		if (fd >= 0)
4522 			err = bitmap_create(mddev);
4523 		if (fd < 0 || err) {
4524 			bitmap_destroy(mddev);
4525 			fd = -1; /* make sure to put the file */
4526 		}
4527 		mddev->pers->quiesce(mddev, 0);
4528 	}
4529 	if (fd < 0) {
4530 		if (mddev->bitmap_file) {
4531 			restore_bitmap_write_access(mddev->bitmap_file);
4532 			fput(mddev->bitmap_file);
4533 		}
4534 		mddev->bitmap_file = NULL;
4535 	}
4536 
4537 	return err;
4538 }
4539 
4540 /*
4541  * set_array_info is used two different ways
4542  * The original usage is when creating a new array.
4543  * In this usage, raid_disks is > 0 and it together with
4544  *  level, size, not_persistent,layout,chunksize determine the
4545  *  shape of the array.
4546  *  This will always create an array with a type-0.90.0 superblock.
4547  * The newer usage is when assembling an array.
4548  *  In this case raid_disks will be 0, and the major_version field is
4549  *  use to determine which style super-blocks are to be found on the devices.
4550  *  The minor and patch _version numbers are also kept incase the
4551  *  super_block handler wishes to interpret them.
4552  */
4553 static int set_array_info(mddev_t * mddev, mdu_array_info_t *info)
4554 {
4555 
4556 	if (info->raid_disks == 0) {
4557 		/* just setting version number for superblock loading */
4558 		if (info->major_version < 0 ||
4559 		    info->major_version >= ARRAY_SIZE(super_types) ||
4560 		    super_types[info->major_version].name == NULL) {
4561 			/* maybe try to auto-load a module? */
4562 			printk(KERN_INFO
4563 				"md: superblock version %d not known\n",
4564 				info->major_version);
4565 			return -EINVAL;
4566 		}
4567 		mddev->major_version = info->major_version;
4568 		mddev->minor_version = info->minor_version;
4569 		mddev->patch_version = info->patch_version;
4570 		mddev->persistent = !info->not_persistent;
4571 		return 0;
4572 	}
4573 	mddev->major_version = MD_MAJOR_VERSION;
4574 	mddev->minor_version = MD_MINOR_VERSION;
4575 	mddev->patch_version = MD_PATCHLEVEL_VERSION;
4576 	mddev->ctime         = get_seconds();
4577 
4578 	mddev->level         = info->level;
4579 	mddev->clevel[0]     = 0;
4580 	mddev->size          = info->size;
4581 	mddev->raid_disks    = info->raid_disks;
4582 	/* don't set md_minor, it is determined by which /dev/md* was
4583 	 * openned
4584 	 */
4585 	if (info->state & (1<<MD_SB_CLEAN))
4586 		mddev->recovery_cp = MaxSector;
4587 	else
4588 		mddev->recovery_cp = 0;
4589 	mddev->persistent    = ! info->not_persistent;
4590 	mddev->external	     = 0;
4591 
4592 	mddev->layout        = info->layout;
4593 	mddev->chunk_size    = info->chunk_size;
4594 
4595 	mddev->max_disks     = MD_SB_DISKS;
4596 
4597 	if (mddev->persistent)
4598 		mddev->flags         = 0;
4599 	set_bit(MD_CHANGE_DEVS, &mddev->flags);
4600 
4601 	mddev->default_bitmap_offset = MD_SB_BYTES >> 9;
4602 	mddev->bitmap_offset = 0;
4603 
4604 	mddev->reshape_position = MaxSector;
4605 
4606 	/*
4607 	 * Generate a 128 bit UUID
4608 	 */
4609 	get_random_bytes(mddev->uuid, 16);
4610 
4611 	mddev->new_level = mddev->level;
4612 	mddev->new_chunk = mddev->chunk_size;
4613 	mddev->new_layout = mddev->layout;
4614 	mddev->delta_disks = 0;
4615 
4616 	return 0;
4617 }
4618 
4619 static int update_size(mddev_t *mddev, sector_t num_sectors)
4620 {
4621 	mdk_rdev_t * rdev;
4622 	int rv;
4623 	struct list_head *tmp;
4624 	int fit = (num_sectors == 0);
4625 
4626 	if (mddev->pers->resize == NULL)
4627 		return -EINVAL;
4628 	/* The "num_sectors" is the number of sectors of each device that
4629 	 * is used.  This can only make sense for arrays with redundancy.
4630 	 * linear and raid0 always use whatever space is available. We can only
4631 	 * consider changing this number if no resync or reconstruction is
4632 	 * happening, and if the new size is acceptable. It must fit before the
4633 	 * sb_start or, if that is <data_offset, it must fit before the size
4634 	 * of each device.  If num_sectors is zero, we find the largest size
4635 	 * that fits.
4636 
4637 	 */
4638 	if (mddev->sync_thread)
4639 		return -EBUSY;
4640 	if (mddev->bitmap)
4641 		/* Sorry, cannot grow a bitmap yet, just remove it,
4642 		 * grow, and re-add.
4643 		 */
4644 		return -EBUSY;
4645 	rdev_for_each(rdev, tmp, mddev) {
4646 		sector_t avail;
4647 		avail = rdev->size * 2;
4648 
4649 		if (fit && (num_sectors == 0 || num_sectors > avail))
4650 			num_sectors = avail;
4651 		if (avail < num_sectors)
4652 			return -ENOSPC;
4653 	}
4654 	rv = mddev->pers->resize(mddev, num_sectors);
4655 	if (!rv) {
4656 		struct block_device *bdev;
4657 
4658 		bdev = bdget_disk(mddev->gendisk, 0);
4659 		if (bdev) {
4660 			mutex_lock(&bdev->bd_inode->i_mutex);
4661 			i_size_write(bdev->bd_inode,
4662 				     (loff_t)mddev->array_sectors << 9);
4663 			mutex_unlock(&bdev->bd_inode->i_mutex);
4664 			bdput(bdev);
4665 		}
4666 	}
4667 	return rv;
4668 }
4669 
4670 static int update_raid_disks(mddev_t *mddev, int raid_disks)
4671 {
4672 	int rv;
4673 	/* change the number of raid disks */
4674 	if (mddev->pers->check_reshape == NULL)
4675 		return -EINVAL;
4676 	if (raid_disks <= 0 ||
4677 	    raid_disks >= mddev->max_disks)
4678 		return -EINVAL;
4679 	if (mddev->sync_thread || mddev->reshape_position != MaxSector)
4680 		return -EBUSY;
4681 	mddev->delta_disks = raid_disks - mddev->raid_disks;
4682 
4683 	rv = mddev->pers->check_reshape(mddev);
4684 	return rv;
4685 }
4686 
4687 
4688 /*
4689  * update_array_info is used to change the configuration of an
4690  * on-line array.
4691  * The version, ctime,level,size,raid_disks,not_persistent, layout,chunk_size
4692  * fields in the info are checked against the array.
4693  * Any differences that cannot be handled will cause an error.
4694  * Normally, only one change can be managed at a time.
4695  */
4696 static int update_array_info(mddev_t *mddev, mdu_array_info_t *info)
4697 {
4698 	int rv = 0;
4699 	int cnt = 0;
4700 	int state = 0;
4701 
4702 	/* calculate expected state,ignoring low bits */
4703 	if (mddev->bitmap && mddev->bitmap_offset)
4704 		state |= (1 << MD_SB_BITMAP_PRESENT);
4705 
4706 	if (mddev->major_version != info->major_version ||
4707 	    mddev->minor_version != info->minor_version ||
4708 /*	    mddev->patch_version != info->patch_version || */
4709 	    mddev->ctime         != info->ctime         ||
4710 	    mddev->level         != info->level         ||
4711 /*	    mddev->layout        != info->layout        || */
4712 	    !mddev->persistent	 != info->not_persistent||
4713 	    mddev->chunk_size    != info->chunk_size    ||
4714 	    /* ignore bottom 8 bits of state, and allow SB_BITMAP_PRESENT to change */
4715 	    ((state^info->state) & 0xfffffe00)
4716 		)
4717 		return -EINVAL;
4718 	/* Check there is only one change */
4719 	if (info->size >= 0 && mddev->size != info->size) cnt++;
4720 	if (mddev->raid_disks != info->raid_disks) cnt++;
4721 	if (mddev->layout != info->layout) cnt++;
4722 	if ((state ^ info->state) & (1<<MD_SB_BITMAP_PRESENT)) cnt++;
4723 	if (cnt == 0) return 0;
4724 	if (cnt > 1) return -EINVAL;
4725 
4726 	if (mddev->layout != info->layout) {
4727 		/* Change layout
4728 		 * we don't need to do anything at the md level, the
4729 		 * personality will take care of it all.
4730 		 */
4731 		if (mddev->pers->reconfig == NULL)
4732 			return -EINVAL;
4733 		else
4734 			return mddev->pers->reconfig(mddev, info->layout, -1);
4735 	}
4736 	if (info->size >= 0 && mddev->size != info->size)
4737 		rv = update_size(mddev, (sector_t)info->size * 2);
4738 
4739 	if (mddev->raid_disks    != info->raid_disks)
4740 		rv = update_raid_disks(mddev, info->raid_disks);
4741 
4742 	if ((state ^ info->state) & (1<<MD_SB_BITMAP_PRESENT)) {
4743 		if (mddev->pers->quiesce == NULL)
4744 			return -EINVAL;
4745 		if (mddev->recovery || mddev->sync_thread)
4746 			return -EBUSY;
4747 		if (info->state & (1<<MD_SB_BITMAP_PRESENT)) {
4748 			/* add the bitmap */
4749 			if (mddev->bitmap)
4750 				return -EEXIST;
4751 			if (mddev->default_bitmap_offset == 0)
4752 				return -EINVAL;
4753 			mddev->bitmap_offset = mddev->default_bitmap_offset;
4754 			mddev->pers->quiesce(mddev, 1);
4755 			rv = bitmap_create(mddev);
4756 			if (rv)
4757 				bitmap_destroy(mddev);
4758 			mddev->pers->quiesce(mddev, 0);
4759 		} else {
4760 			/* remove the bitmap */
4761 			if (!mddev->bitmap)
4762 				return -ENOENT;
4763 			if (mddev->bitmap->file)
4764 				return -EINVAL;
4765 			mddev->pers->quiesce(mddev, 1);
4766 			bitmap_destroy(mddev);
4767 			mddev->pers->quiesce(mddev, 0);
4768 			mddev->bitmap_offset = 0;
4769 		}
4770 	}
4771 	md_update_sb(mddev, 1);
4772 	return rv;
4773 }
4774 
4775 static int set_disk_faulty(mddev_t *mddev, dev_t dev)
4776 {
4777 	mdk_rdev_t *rdev;
4778 
4779 	if (mddev->pers == NULL)
4780 		return -ENODEV;
4781 
4782 	rdev = find_rdev(mddev, dev);
4783 	if (!rdev)
4784 		return -ENODEV;
4785 
4786 	md_error(mddev, rdev);
4787 	return 0;
4788 }
4789 
4790 /*
4791  * We have a problem here : there is no easy way to give a CHS
4792  * virtual geometry. We currently pretend that we have a 2 heads
4793  * 4 sectors (with a BIG number of cylinders...). This drives
4794  * dosfs just mad... ;-)
4795  */
4796 static int md_getgeo(struct block_device *bdev, struct hd_geometry *geo)
4797 {
4798 	mddev_t *mddev = bdev->bd_disk->private_data;
4799 
4800 	geo->heads = 2;
4801 	geo->sectors = 4;
4802 	geo->cylinders = get_capacity(mddev->gendisk) / 8;
4803 	return 0;
4804 }
4805 
4806 static int md_ioctl(struct inode *inode, struct file *file,
4807 			unsigned int cmd, unsigned long arg)
4808 {
4809 	int err = 0;
4810 	void __user *argp = (void __user *)arg;
4811 	mddev_t *mddev = NULL;
4812 
4813 	if (!capable(CAP_SYS_ADMIN))
4814 		return -EACCES;
4815 
4816 	/*
4817 	 * Commands dealing with the RAID driver but not any
4818 	 * particular array:
4819 	 */
4820 	switch (cmd)
4821 	{
4822 		case RAID_VERSION:
4823 			err = get_version(argp);
4824 			goto done;
4825 
4826 		case PRINT_RAID_DEBUG:
4827 			err = 0;
4828 			md_print_devices();
4829 			goto done;
4830 
4831 #ifndef MODULE
4832 		case RAID_AUTORUN:
4833 			err = 0;
4834 			autostart_arrays(arg);
4835 			goto done;
4836 #endif
4837 		default:;
4838 	}
4839 
4840 	/*
4841 	 * Commands creating/starting a new array:
4842 	 */
4843 
4844 	mddev = inode->i_bdev->bd_disk->private_data;
4845 
4846 	if (!mddev) {
4847 		BUG();
4848 		goto abort;
4849 	}
4850 
4851 	err = mddev_lock(mddev);
4852 	if (err) {
4853 		printk(KERN_INFO
4854 			"md: ioctl lock interrupted, reason %d, cmd %d\n",
4855 			err, cmd);
4856 		goto abort;
4857 	}
4858 
4859 	switch (cmd)
4860 	{
4861 		case SET_ARRAY_INFO:
4862 			{
4863 				mdu_array_info_t info;
4864 				if (!arg)
4865 					memset(&info, 0, sizeof(info));
4866 				else if (copy_from_user(&info, argp, sizeof(info))) {
4867 					err = -EFAULT;
4868 					goto abort_unlock;
4869 				}
4870 				if (mddev->pers) {
4871 					err = update_array_info(mddev, &info);
4872 					if (err) {
4873 						printk(KERN_WARNING "md: couldn't update"
4874 						       " array info. %d\n", err);
4875 						goto abort_unlock;
4876 					}
4877 					goto done_unlock;
4878 				}
4879 				if (!list_empty(&mddev->disks)) {
4880 					printk(KERN_WARNING
4881 					       "md: array %s already has disks!\n",
4882 					       mdname(mddev));
4883 					err = -EBUSY;
4884 					goto abort_unlock;
4885 				}
4886 				if (mddev->raid_disks) {
4887 					printk(KERN_WARNING
4888 					       "md: array %s already initialised!\n",
4889 					       mdname(mddev));
4890 					err = -EBUSY;
4891 					goto abort_unlock;
4892 				}
4893 				err = set_array_info(mddev, &info);
4894 				if (err) {
4895 					printk(KERN_WARNING "md: couldn't set"
4896 					       " array info. %d\n", err);
4897 					goto abort_unlock;
4898 				}
4899 			}
4900 			goto done_unlock;
4901 
4902 		default:;
4903 	}
4904 
4905 	/*
4906 	 * Commands querying/configuring an existing array:
4907 	 */
4908 	/* if we are not initialised yet, only ADD_NEW_DISK, STOP_ARRAY,
4909 	 * RUN_ARRAY, and GET_ and SET_BITMAP_FILE are allowed */
4910 	if ((!mddev->raid_disks && !mddev->external)
4911 	    && cmd != ADD_NEW_DISK && cmd != STOP_ARRAY
4912 	    && cmd != RUN_ARRAY && cmd != SET_BITMAP_FILE
4913 	    && cmd != GET_BITMAP_FILE) {
4914 		err = -ENODEV;
4915 		goto abort_unlock;
4916 	}
4917 
4918 	/*
4919 	 * Commands even a read-only array can execute:
4920 	 */
4921 	switch (cmd)
4922 	{
4923 		case GET_ARRAY_INFO:
4924 			err = get_array_info(mddev, argp);
4925 			goto done_unlock;
4926 
4927 		case GET_BITMAP_FILE:
4928 			err = get_bitmap_file(mddev, argp);
4929 			goto done_unlock;
4930 
4931 		case GET_DISK_INFO:
4932 			err = get_disk_info(mddev, argp);
4933 			goto done_unlock;
4934 
4935 		case RESTART_ARRAY_RW:
4936 			err = restart_array(mddev);
4937 			goto done_unlock;
4938 
4939 		case STOP_ARRAY:
4940 			err = do_md_stop (mddev, 0, 1);
4941 			goto done_unlock;
4942 
4943 		case STOP_ARRAY_RO:
4944 			err = do_md_stop (mddev, 1, 1);
4945 			goto done_unlock;
4946 
4947 	}
4948 
4949 	/*
4950 	 * The remaining ioctls are changing the state of the
4951 	 * superblock, so we do not allow them on read-only arrays.
4952 	 * However non-MD ioctls (e.g. get-size) will still come through
4953 	 * here and hit the 'default' below, so only disallow
4954 	 * 'md' ioctls, and switch to rw mode if started auto-readonly.
4955 	 */
4956 	if (_IOC_TYPE(cmd) == MD_MAJOR && mddev->ro && mddev->pers) {
4957 		if (mddev->ro == 2) {
4958 			mddev->ro = 0;
4959 			sysfs_notify(&mddev->kobj, NULL, "array_state");
4960 			set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
4961 			md_wakeup_thread(mddev->thread);
4962 		} else {
4963 			err = -EROFS;
4964 			goto abort_unlock;
4965 		}
4966 	}
4967 
4968 	switch (cmd)
4969 	{
4970 		case ADD_NEW_DISK:
4971 		{
4972 			mdu_disk_info_t info;
4973 			if (copy_from_user(&info, argp, sizeof(info)))
4974 				err = -EFAULT;
4975 			else
4976 				err = add_new_disk(mddev, &info);
4977 			goto done_unlock;
4978 		}
4979 
4980 		case HOT_REMOVE_DISK:
4981 			err = hot_remove_disk(mddev, new_decode_dev(arg));
4982 			goto done_unlock;
4983 
4984 		case HOT_ADD_DISK:
4985 			err = hot_add_disk(mddev, new_decode_dev(arg));
4986 			goto done_unlock;
4987 
4988 		case SET_DISK_FAULTY:
4989 			err = set_disk_faulty(mddev, new_decode_dev(arg));
4990 			goto done_unlock;
4991 
4992 		case RUN_ARRAY:
4993 			err = do_md_run (mddev);
4994 			goto done_unlock;
4995 
4996 		case SET_BITMAP_FILE:
4997 			err = set_bitmap_file(mddev, (int)arg);
4998 			goto done_unlock;
4999 
5000 		default:
5001 			err = -EINVAL;
5002 			goto abort_unlock;
5003 	}
5004 
5005 done_unlock:
5006 abort_unlock:
5007 	mddev_unlock(mddev);
5008 
5009 	return err;
5010 done:
5011 	if (err)
5012 		MD_BUG();
5013 abort:
5014 	return err;
5015 }
5016 
5017 static int md_open(struct inode *inode, struct file *file)
5018 {
5019 	/*
5020 	 * Succeed if we can lock the mddev, which confirms that
5021 	 * it isn't being stopped right now.
5022 	 */
5023 	mddev_t *mddev = inode->i_bdev->bd_disk->private_data;
5024 	int err;
5025 
5026 	if ((err = mutex_lock_interruptible_nested(&mddev->reconfig_mutex, 1)))
5027 		goto out;
5028 
5029 	err = 0;
5030 	mddev_get(mddev);
5031 	atomic_inc(&mddev->openers);
5032 	mddev_unlock(mddev);
5033 
5034 	check_disk_change(inode->i_bdev);
5035  out:
5036 	return err;
5037 }
5038 
5039 static int md_release(struct inode *inode, struct file * file)
5040 {
5041  	mddev_t *mddev = inode->i_bdev->bd_disk->private_data;
5042 
5043 	BUG_ON(!mddev);
5044 	atomic_dec(&mddev->openers);
5045 	mddev_put(mddev);
5046 
5047 	return 0;
5048 }
5049 
5050 static int md_media_changed(struct gendisk *disk)
5051 {
5052 	mddev_t *mddev = disk->private_data;
5053 
5054 	return mddev->changed;
5055 }
5056 
5057 static int md_revalidate(struct gendisk *disk)
5058 {
5059 	mddev_t *mddev = disk->private_data;
5060 
5061 	mddev->changed = 0;
5062 	return 0;
5063 }
5064 static struct block_device_operations md_fops =
5065 {
5066 	.owner		= THIS_MODULE,
5067 	.open		= md_open,
5068 	.release	= md_release,
5069 	.ioctl		= md_ioctl,
5070 	.getgeo		= md_getgeo,
5071 	.media_changed	= md_media_changed,
5072 	.revalidate_disk= md_revalidate,
5073 };
5074 
5075 static int md_thread(void * arg)
5076 {
5077 	mdk_thread_t *thread = arg;
5078 
5079 	/*
5080 	 * md_thread is a 'system-thread', it's priority should be very
5081 	 * high. We avoid resource deadlocks individually in each
5082 	 * raid personality. (RAID5 does preallocation) We also use RR and
5083 	 * the very same RT priority as kswapd, thus we will never get
5084 	 * into a priority inversion deadlock.
5085 	 *
5086 	 * we definitely have to have equal or higher priority than
5087 	 * bdflush, otherwise bdflush will deadlock if there are too
5088 	 * many dirty RAID5 blocks.
5089 	 */
5090 
5091 	allow_signal(SIGKILL);
5092 	while (!kthread_should_stop()) {
5093 
5094 		/* We need to wait INTERRUPTIBLE so that
5095 		 * we don't add to the load-average.
5096 		 * That means we need to be sure no signals are
5097 		 * pending
5098 		 */
5099 		if (signal_pending(current))
5100 			flush_signals(current);
5101 
5102 		wait_event_interruptible_timeout
5103 			(thread->wqueue,
5104 			 test_bit(THREAD_WAKEUP, &thread->flags)
5105 			 || kthread_should_stop(),
5106 			 thread->timeout);
5107 
5108 		clear_bit(THREAD_WAKEUP, &thread->flags);
5109 
5110 		thread->run(thread->mddev);
5111 	}
5112 
5113 	return 0;
5114 }
5115 
5116 void md_wakeup_thread(mdk_thread_t *thread)
5117 {
5118 	if (thread) {
5119 		dprintk("md: waking up MD thread %s.\n", thread->tsk->comm);
5120 		set_bit(THREAD_WAKEUP, &thread->flags);
5121 		wake_up(&thread->wqueue);
5122 	}
5123 }
5124 
5125 mdk_thread_t *md_register_thread(void (*run) (mddev_t *), mddev_t *mddev,
5126 				 const char *name)
5127 {
5128 	mdk_thread_t *thread;
5129 
5130 	thread = kzalloc(sizeof(mdk_thread_t), GFP_KERNEL);
5131 	if (!thread)
5132 		return NULL;
5133 
5134 	init_waitqueue_head(&thread->wqueue);
5135 
5136 	thread->run = run;
5137 	thread->mddev = mddev;
5138 	thread->timeout = MAX_SCHEDULE_TIMEOUT;
5139 	thread->tsk = kthread_run(md_thread, thread, name, mdname(thread->mddev));
5140 	if (IS_ERR(thread->tsk)) {
5141 		kfree(thread);
5142 		return NULL;
5143 	}
5144 	return thread;
5145 }
5146 
5147 void md_unregister_thread(mdk_thread_t *thread)
5148 {
5149 	dprintk("interrupting MD-thread pid %d\n", task_pid_nr(thread->tsk));
5150 
5151 	kthread_stop(thread->tsk);
5152 	kfree(thread);
5153 }
5154 
5155 void md_error(mddev_t *mddev, mdk_rdev_t *rdev)
5156 {
5157 	if (!mddev) {
5158 		MD_BUG();
5159 		return;
5160 	}
5161 
5162 	if (!rdev || test_bit(Faulty, &rdev->flags))
5163 		return;
5164 
5165 	if (mddev->external)
5166 		set_bit(Blocked, &rdev->flags);
5167 /*
5168 	dprintk("md_error dev:%s, rdev:(%d:%d), (caller: %p,%p,%p,%p).\n",
5169 		mdname(mddev),
5170 		MAJOR(rdev->bdev->bd_dev), MINOR(rdev->bdev->bd_dev),
5171 		__builtin_return_address(0),__builtin_return_address(1),
5172 		__builtin_return_address(2),__builtin_return_address(3));
5173 */
5174 	if (!mddev->pers)
5175 		return;
5176 	if (!mddev->pers->error_handler)
5177 		return;
5178 	mddev->pers->error_handler(mddev,rdev);
5179 	if (mddev->degraded)
5180 		set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
5181 	set_bit(StateChanged, &rdev->flags);
5182 	set_bit(MD_RECOVERY_INTR, &mddev->recovery);
5183 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
5184 	md_wakeup_thread(mddev->thread);
5185 	md_new_event_inintr(mddev);
5186 }
5187 
5188 /* seq_file implementation /proc/mdstat */
5189 
5190 static void status_unused(struct seq_file *seq)
5191 {
5192 	int i = 0;
5193 	mdk_rdev_t *rdev;
5194 	struct list_head *tmp;
5195 
5196 	seq_printf(seq, "unused devices: ");
5197 
5198 	rdev_for_each_list(rdev, tmp, pending_raid_disks) {
5199 		char b[BDEVNAME_SIZE];
5200 		i++;
5201 		seq_printf(seq, "%s ",
5202 			      bdevname(rdev->bdev,b));
5203 	}
5204 	if (!i)
5205 		seq_printf(seq, "<none>");
5206 
5207 	seq_printf(seq, "\n");
5208 }
5209 
5210 
5211 static void status_resync(struct seq_file *seq, mddev_t * mddev)
5212 {
5213 	sector_t max_blocks, resync, res;
5214 	unsigned long dt, db, rt;
5215 	int scale;
5216 	unsigned int per_milli;
5217 
5218 	resync = (mddev->curr_resync - atomic_read(&mddev->recovery_active))/2;
5219 
5220 	if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery))
5221 		max_blocks = mddev->resync_max_sectors >> 1;
5222 	else
5223 		max_blocks = mddev->size;
5224 
5225 	/*
5226 	 * Should not happen.
5227 	 */
5228 	if (!max_blocks) {
5229 		MD_BUG();
5230 		return;
5231 	}
5232 	/* Pick 'scale' such that (resync>>scale)*1000 will fit
5233 	 * in a sector_t, and (max_blocks>>scale) will fit in a
5234 	 * u32, as those are the requirements for sector_div.
5235 	 * Thus 'scale' must be at least 10
5236 	 */
5237 	scale = 10;
5238 	if (sizeof(sector_t) > sizeof(unsigned long)) {
5239 		while ( max_blocks/2 > (1ULL<<(scale+32)))
5240 			scale++;
5241 	}
5242 	res = (resync>>scale)*1000;
5243 	sector_div(res, (u32)((max_blocks>>scale)+1));
5244 
5245 	per_milli = res;
5246 	{
5247 		int i, x = per_milli/50, y = 20-x;
5248 		seq_printf(seq, "[");
5249 		for (i = 0; i < x; i++)
5250 			seq_printf(seq, "=");
5251 		seq_printf(seq, ">");
5252 		for (i = 0; i < y; i++)
5253 			seq_printf(seq, ".");
5254 		seq_printf(seq, "] ");
5255 	}
5256 	seq_printf(seq, " %s =%3u.%u%% (%llu/%llu)",
5257 		   (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)?
5258 		    "reshape" :
5259 		    (test_bit(MD_RECOVERY_CHECK, &mddev->recovery)?
5260 		     "check" :
5261 		     (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) ?
5262 		      "resync" : "recovery"))),
5263 		   per_milli/10, per_milli % 10,
5264 		   (unsigned long long) resync,
5265 		   (unsigned long long) max_blocks);
5266 
5267 	/*
5268 	 * We do not want to overflow, so the order of operands and
5269 	 * the * 100 / 100 trick are important. We do a +1 to be
5270 	 * safe against division by zero. We only estimate anyway.
5271 	 *
5272 	 * dt: time from mark until now
5273 	 * db: blocks written from mark until now
5274 	 * rt: remaining time
5275 	 */
5276 	dt = ((jiffies - mddev->resync_mark) / HZ);
5277 	if (!dt) dt++;
5278 	db = (mddev->curr_mark_cnt - atomic_read(&mddev->recovery_active))
5279 		- mddev->resync_mark_cnt;
5280 	rt = (dt * ((unsigned long)(max_blocks-resync) / (db/2/100+1)))/100;
5281 
5282 	seq_printf(seq, " finish=%lu.%lumin", rt / 60, (rt % 60)/6);
5283 
5284 	seq_printf(seq, " speed=%ldK/sec", db/2/dt);
5285 }
5286 
5287 static void *md_seq_start(struct seq_file *seq, loff_t *pos)
5288 {
5289 	struct list_head *tmp;
5290 	loff_t l = *pos;
5291 	mddev_t *mddev;
5292 
5293 	if (l >= 0x10000)
5294 		return NULL;
5295 	if (!l--)
5296 		/* header */
5297 		return (void*)1;
5298 
5299 	spin_lock(&all_mddevs_lock);
5300 	list_for_each(tmp,&all_mddevs)
5301 		if (!l--) {
5302 			mddev = list_entry(tmp, mddev_t, all_mddevs);
5303 			mddev_get(mddev);
5304 			spin_unlock(&all_mddevs_lock);
5305 			return mddev;
5306 		}
5307 	spin_unlock(&all_mddevs_lock);
5308 	if (!l--)
5309 		return (void*)2;/* tail */
5310 	return NULL;
5311 }
5312 
5313 static void *md_seq_next(struct seq_file *seq, void *v, loff_t *pos)
5314 {
5315 	struct list_head *tmp;
5316 	mddev_t *next_mddev, *mddev = v;
5317 
5318 	++*pos;
5319 	if (v == (void*)2)
5320 		return NULL;
5321 
5322 	spin_lock(&all_mddevs_lock);
5323 	if (v == (void*)1)
5324 		tmp = all_mddevs.next;
5325 	else
5326 		tmp = mddev->all_mddevs.next;
5327 	if (tmp != &all_mddevs)
5328 		next_mddev = mddev_get(list_entry(tmp,mddev_t,all_mddevs));
5329 	else {
5330 		next_mddev = (void*)2;
5331 		*pos = 0x10000;
5332 	}
5333 	spin_unlock(&all_mddevs_lock);
5334 
5335 	if (v != (void*)1)
5336 		mddev_put(mddev);
5337 	return next_mddev;
5338 
5339 }
5340 
5341 static void md_seq_stop(struct seq_file *seq, void *v)
5342 {
5343 	mddev_t *mddev = v;
5344 
5345 	if (mddev && v != (void*)1 && v != (void*)2)
5346 		mddev_put(mddev);
5347 }
5348 
5349 struct mdstat_info {
5350 	int event;
5351 };
5352 
5353 static int md_seq_show(struct seq_file *seq, void *v)
5354 {
5355 	mddev_t *mddev = v;
5356 	sector_t size;
5357 	struct list_head *tmp2;
5358 	mdk_rdev_t *rdev;
5359 	struct mdstat_info *mi = seq->private;
5360 	struct bitmap *bitmap;
5361 
5362 	if (v == (void*)1) {
5363 		struct mdk_personality *pers;
5364 		seq_printf(seq, "Personalities : ");
5365 		spin_lock(&pers_lock);
5366 		list_for_each_entry(pers, &pers_list, list)
5367 			seq_printf(seq, "[%s] ", pers->name);
5368 
5369 		spin_unlock(&pers_lock);
5370 		seq_printf(seq, "\n");
5371 		mi->event = atomic_read(&md_event_count);
5372 		return 0;
5373 	}
5374 	if (v == (void*)2) {
5375 		status_unused(seq);
5376 		return 0;
5377 	}
5378 
5379 	if (mddev_lock(mddev) < 0)
5380 		return -EINTR;
5381 
5382 	if (mddev->pers || mddev->raid_disks || !list_empty(&mddev->disks)) {
5383 		seq_printf(seq, "%s : %sactive", mdname(mddev),
5384 						mddev->pers ? "" : "in");
5385 		if (mddev->pers) {
5386 			if (mddev->ro==1)
5387 				seq_printf(seq, " (read-only)");
5388 			if (mddev->ro==2)
5389 				seq_printf(seq, " (auto-read-only)");
5390 			seq_printf(seq, " %s", mddev->pers->name);
5391 		}
5392 
5393 		size = 0;
5394 		rdev_for_each(rdev, tmp2, mddev) {
5395 			char b[BDEVNAME_SIZE];
5396 			seq_printf(seq, " %s[%d]",
5397 				bdevname(rdev->bdev,b), rdev->desc_nr);
5398 			if (test_bit(WriteMostly, &rdev->flags))
5399 				seq_printf(seq, "(W)");
5400 			if (test_bit(Faulty, &rdev->flags)) {
5401 				seq_printf(seq, "(F)");
5402 				continue;
5403 			} else if (rdev->raid_disk < 0)
5404 				seq_printf(seq, "(S)"); /* spare */
5405 			size += rdev->size;
5406 		}
5407 
5408 		if (!list_empty(&mddev->disks)) {
5409 			if (mddev->pers)
5410 				seq_printf(seq, "\n      %llu blocks",
5411 					   (unsigned long long)
5412 					   mddev->array_sectors / 2);
5413 			else
5414 				seq_printf(seq, "\n      %llu blocks",
5415 					   (unsigned long long)size);
5416 		}
5417 		if (mddev->persistent) {
5418 			if (mddev->major_version != 0 ||
5419 			    mddev->minor_version != 90) {
5420 				seq_printf(seq," super %d.%d",
5421 					   mddev->major_version,
5422 					   mddev->minor_version);
5423 			}
5424 		} else if (mddev->external)
5425 			seq_printf(seq, " super external:%s",
5426 				   mddev->metadata_type);
5427 		else
5428 			seq_printf(seq, " super non-persistent");
5429 
5430 		if (mddev->pers) {
5431 			mddev->pers->status (seq, mddev);
5432 	 		seq_printf(seq, "\n      ");
5433 			if (mddev->pers->sync_request) {
5434 				if (mddev->curr_resync > 2) {
5435 					status_resync (seq, mddev);
5436 					seq_printf(seq, "\n      ");
5437 				} else if (mddev->curr_resync == 1 || mddev->curr_resync == 2)
5438 					seq_printf(seq, "\tresync=DELAYED\n      ");
5439 				else if (mddev->recovery_cp < MaxSector)
5440 					seq_printf(seq, "\tresync=PENDING\n      ");
5441 			}
5442 		} else
5443 			seq_printf(seq, "\n       ");
5444 
5445 		if ((bitmap = mddev->bitmap)) {
5446 			unsigned long chunk_kb;
5447 			unsigned long flags;
5448 			spin_lock_irqsave(&bitmap->lock, flags);
5449 			chunk_kb = bitmap->chunksize >> 10;
5450 			seq_printf(seq, "bitmap: %lu/%lu pages [%luKB], "
5451 				"%lu%s chunk",
5452 				bitmap->pages - bitmap->missing_pages,
5453 				bitmap->pages,
5454 				(bitmap->pages - bitmap->missing_pages)
5455 					<< (PAGE_SHIFT - 10),
5456 				chunk_kb ? chunk_kb : bitmap->chunksize,
5457 				chunk_kb ? "KB" : "B");
5458 			if (bitmap->file) {
5459 				seq_printf(seq, ", file: ");
5460 				seq_path(seq, &bitmap->file->f_path, " \t\n");
5461 			}
5462 
5463 			seq_printf(seq, "\n");
5464 			spin_unlock_irqrestore(&bitmap->lock, flags);
5465 		}
5466 
5467 		seq_printf(seq, "\n");
5468 	}
5469 	mddev_unlock(mddev);
5470 
5471 	return 0;
5472 }
5473 
5474 static struct seq_operations md_seq_ops = {
5475 	.start  = md_seq_start,
5476 	.next   = md_seq_next,
5477 	.stop   = md_seq_stop,
5478 	.show   = md_seq_show,
5479 };
5480 
5481 static int md_seq_open(struct inode *inode, struct file *file)
5482 {
5483 	int error;
5484 	struct mdstat_info *mi = kmalloc(sizeof(*mi), GFP_KERNEL);
5485 	if (mi == NULL)
5486 		return -ENOMEM;
5487 
5488 	error = seq_open(file, &md_seq_ops);
5489 	if (error)
5490 		kfree(mi);
5491 	else {
5492 		struct seq_file *p = file->private_data;
5493 		p->private = mi;
5494 		mi->event = atomic_read(&md_event_count);
5495 	}
5496 	return error;
5497 }
5498 
5499 static unsigned int mdstat_poll(struct file *filp, poll_table *wait)
5500 {
5501 	struct seq_file *m = filp->private_data;
5502 	struct mdstat_info *mi = m->private;
5503 	int mask;
5504 
5505 	poll_wait(filp, &md_event_waiters, wait);
5506 
5507 	/* always allow read */
5508 	mask = POLLIN | POLLRDNORM;
5509 
5510 	if (mi->event != atomic_read(&md_event_count))
5511 		mask |= POLLERR | POLLPRI;
5512 	return mask;
5513 }
5514 
5515 static const struct file_operations md_seq_fops = {
5516 	.owner		= THIS_MODULE,
5517 	.open           = md_seq_open,
5518 	.read           = seq_read,
5519 	.llseek         = seq_lseek,
5520 	.release	= seq_release_private,
5521 	.poll		= mdstat_poll,
5522 };
5523 
5524 int register_md_personality(struct mdk_personality *p)
5525 {
5526 	spin_lock(&pers_lock);
5527 	list_add_tail(&p->list, &pers_list);
5528 	printk(KERN_INFO "md: %s personality registered for level %d\n", p->name, p->level);
5529 	spin_unlock(&pers_lock);
5530 	return 0;
5531 }
5532 
5533 int unregister_md_personality(struct mdk_personality *p)
5534 {
5535 	printk(KERN_INFO "md: %s personality unregistered\n", p->name);
5536 	spin_lock(&pers_lock);
5537 	list_del_init(&p->list);
5538 	spin_unlock(&pers_lock);
5539 	return 0;
5540 }
5541 
5542 static int is_mddev_idle(mddev_t *mddev)
5543 {
5544 	mdk_rdev_t * rdev;
5545 	int idle;
5546 	long curr_events;
5547 
5548 	idle = 1;
5549 	rcu_read_lock();
5550 	rdev_for_each_rcu(rdev, mddev) {
5551 		struct gendisk *disk = rdev->bdev->bd_contains->bd_disk;
5552 		curr_events = disk_stat_read(disk, sectors[0]) +
5553 				disk_stat_read(disk, sectors[1]) -
5554 				atomic_read(&disk->sync_io);
5555 		/* sync IO will cause sync_io to increase before the disk_stats
5556 		 * as sync_io is counted when a request starts, and
5557 		 * disk_stats is counted when it completes.
5558 		 * So resync activity will cause curr_events to be smaller than
5559 		 * when there was no such activity.
5560 		 * non-sync IO will cause disk_stat to increase without
5561 		 * increasing sync_io so curr_events will (eventually)
5562 		 * be larger than it was before.  Once it becomes
5563 		 * substantially larger, the test below will cause
5564 		 * the array to appear non-idle, and resync will slow
5565 		 * down.
5566 		 * If there is a lot of outstanding resync activity when
5567 		 * we set last_event to curr_events, then all that activity
5568 		 * completing might cause the array to appear non-idle
5569 		 * and resync will be slowed down even though there might
5570 		 * not have been non-resync activity.  This will only
5571 		 * happen once though.  'last_events' will soon reflect
5572 		 * the state where there is little or no outstanding
5573 		 * resync requests, and further resync activity will
5574 		 * always make curr_events less than last_events.
5575 		 *
5576 		 */
5577 		if (curr_events - rdev->last_events > 4096) {
5578 			rdev->last_events = curr_events;
5579 			idle = 0;
5580 		}
5581 	}
5582 	rcu_read_unlock();
5583 	return idle;
5584 }
5585 
5586 void md_done_sync(mddev_t *mddev, int blocks, int ok)
5587 {
5588 	/* another "blocks" (512byte) blocks have been synced */
5589 	atomic_sub(blocks, &mddev->recovery_active);
5590 	wake_up(&mddev->recovery_wait);
5591 	if (!ok) {
5592 		set_bit(MD_RECOVERY_INTR, &mddev->recovery);
5593 		md_wakeup_thread(mddev->thread);
5594 		// stop recovery, signal do_sync ....
5595 	}
5596 }
5597 
5598 
5599 /* md_write_start(mddev, bi)
5600  * If we need to update some array metadata (e.g. 'active' flag
5601  * in superblock) before writing, schedule a superblock update
5602  * and wait for it to complete.
5603  */
5604 void md_write_start(mddev_t *mddev, struct bio *bi)
5605 {
5606 	int did_change = 0;
5607 	if (bio_data_dir(bi) != WRITE)
5608 		return;
5609 
5610 	BUG_ON(mddev->ro == 1);
5611 	if (mddev->ro == 2) {
5612 		/* need to switch to read/write */
5613 		mddev->ro = 0;
5614 		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
5615 		md_wakeup_thread(mddev->thread);
5616 		md_wakeup_thread(mddev->sync_thread);
5617 		did_change = 1;
5618 	}
5619 	atomic_inc(&mddev->writes_pending);
5620 	if (mddev->safemode == 1)
5621 		mddev->safemode = 0;
5622 	if (mddev->in_sync) {
5623 		spin_lock_irq(&mddev->write_lock);
5624 		if (mddev->in_sync) {
5625 			mddev->in_sync = 0;
5626 			set_bit(MD_CHANGE_CLEAN, &mddev->flags);
5627 			md_wakeup_thread(mddev->thread);
5628 			did_change = 1;
5629 		}
5630 		spin_unlock_irq(&mddev->write_lock);
5631 	}
5632 	if (did_change)
5633 		sysfs_notify(&mddev->kobj, NULL, "array_state");
5634 	wait_event(mddev->sb_wait,
5635 		   !test_bit(MD_CHANGE_CLEAN, &mddev->flags) &&
5636 		   !test_bit(MD_CHANGE_PENDING, &mddev->flags));
5637 }
5638 
5639 void md_write_end(mddev_t *mddev)
5640 {
5641 	if (atomic_dec_and_test(&mddev->writes_pending)) {
5642 		if (mddev->safemode == 2)
5643 			md_wakeup_thread(mddev->thread);
5644 		else if (mddev->safemode_delay)
5645 			mod_timer(&mddev->safemode_timer, jiffies + mddev->safemode_delay);
5646 	}
5647 }
5648 
5649 /* md_allow_write(mddev)
5650  * Calling this ensures that the array is marked 'active' so that writes
5651  * may proceed without blocking.  It is important to call this before
5652  * attempting a GFP_KERNEL allocation while holding the mddev lock.
5653  * Must be called with mddev_lock held.
5654  *
5655  * In the ->external case MD_CHANGE_CLEAN can not be cleared until mddev->lock
5656  * is dropped, so return -EAGAIN after notifying userspace.
5657  */
5658 int md_allow_write(mddev_t *mddev)
5659 {
5660 	if (!mddev->pers)
5661 		return 0;
5662 	if (mddev->ro)
5663 		return 0;
5664 	if (!mddev->pers->sync_request)
5665 		return 0;
5666 
5667 	spin_lock_irq(&mddev->write_lock);
5668 	if (mddev->in_sync) {
5669 		mddev->in_sync = 0;
5670 		set_bit(MD_CHANGE_CLEAN, &mddev->flags);
5671 		if (mddev->safemode_delay &&
5672 		    mddev->safemode == 0)
5673 			mddev->safemode = 1;
5674 		spin_unlock_irq(&mddev->write_lock);
5675 		md_update_sb(mddev, 0);
5676 		sysfs_notify(&mddev->kobj, NULL, "array_state");
5677 	} else
5678 		spin_unlock_irq(&mddev->write_lock);
5679 
5680 	if (test_bit(MD_CHANGE_CLEAN, &mddev->flags))
5681 		return -EAGAIN;
5682 	else
5683 		return 0;
5684 }
5685 EXPORT_SYMBOL_GPL(md_allow_write);
5686 
5687 #define SYNC_MARKS	10
5688 #define	SYNC_MARK_STEP	(3*HZ)
5689 void md_do_sync(mddev_t *mddev)
5690 {
5691 	mddev_t *mddev2;
5692 	unsigned int currspeed = 0,
5693 		 window;
5694 	sector_t max_sectors,j, io_sectors;
5695 	unsigned long mark[SYNC_MARKS];
5696 	sector_t mark_cnt[SYNC_MARKS];
5697 	int last_mark,m;
5698 	struct list_head *tmp;
5699 	sector_t last_check;
5700 	int skipped = 0;
5701 	struct list_head *rtmp;
5702 	mdk_rdev_t *rdev;
5703 	char *desc;
5704 
5705 	/* just incase thread restarts... */
5706 	if (test_bit(MD_RECOVERY_DONE, &mddev->recovery))
5707 		return;
5708 	if (mddev->ro) /* never try to sync a read-only array */
5709 		return;
5710 
5711 	if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
5712 		if (test_bit(MD_RECOVERY_CHECK, &mddev->recovery))
5713 			desc = "data-check";
5714 		else if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
5715 			desc = "requested-resync";
5716 		else
5717 			desc = "resync";
5718 	} else if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
5719 		desc = "reshape";
5720 	else
5721 		desc = "recovery";
5722 
5723 	/* we overload curr_resync somewhat here.
5724 	 * 0 == not engaged in resync at all
5725 	 * 2 == checking that there is no conflict with another sync
5726 	 * 1 == like 2, but have yielded to allow conflicting resync to
5727 	 *		commense
5728 	 * other == active in resync - this many blocks
5729 	 *
5730 	 * Before starting a resync we must have set curr_resync to
5731 	 * 2, and then checked that every "conflicting" array has curr_resync
5732 	 * less than ours.  When we find one that is the same or higher
5733 	 * we wait on resync_wait.  To avoid deadlock, we reduce curr_resync
5734 	 * to 1 if we choose to yield (based arbitrarily on address of mddev structure).
5735 	 * This will mean we have to start checking from the beginning again.
5736 	 *
5737 	 */
5738 
5739 	do {
5740 		mddev->curr_resync = 2;
5741 
5742 	try_again:
5743 		if (kthread_should_stop()) {
5744 			set_bit(MD_RECOVERY_INTR, &mddev->recovery);
5745 			goto skip;
5746 		}
5747 		for_each_mddev(mddev2, tmp) {
5748 			if (mddev2 == mddev)
5749 				continue;
5750 			if (!mddev->parallel_resync
5751 			&&  mddev2->curr_resync
5752 			&&  match_mddev_units(mddev, mddev2)) {
5753 				DEFINE_WAIT(wq);
5754 				if (mddev < mddev2 && mddev->curr_resync == 2) {
5755 					/* arbitrarily yield */
5756 					mddev->curr_resync = 1;
5757 					wake_up(&resync_wait);
5758 				}
5759 				if (mddev > mddev2 && mddev->curr_resync == 1)
5760 					/* no need to wait here, we can wait the next
5761 					 * time 'round when curr_resync == 2
5762 					 */
5763 					continue;
5764 				/* We need to wait 'interruptible' so as not to
5765 				 * contribute to the load average, and not to
5766 				 * be caught by 'softlockup'
5767 				 */
5768 				prepare_to_wait(&resync_wait, &wq, TASK_INTERRUPTIBLE);
5769 				if (!kthread_should_stop() &&
5770 				    mddev2->curr_resync >= mddev->curr_resync) {
5771 					printk(KERN_INFO "md: delaying %s of %s"
5772 					       " until %s has finished (they"
5773 					       " share one or more physical units)\n",
5774 					       desc, mdname(mddev), mdname(mddev2));
5775 					mddev_put(mddev2);
5776 					if (signal_pending(current))
5777 						flush_signals(current);
5778 					schedule();
5779 					finish_wait(&resync_wait, &wq);
5780 					goto try_again;
5781 				}
5782 				finish_wait(&resync_wait, &wq);
5783 			}
5784 		}
5785 	} while (mddev->curr_resync < 2);
5786 
5787 	j = 0;
5788 	if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
5789 		/* resync follows the size requested by the personality,
5790 		 * which defaults to physical size, but can be virtual size
5791 		 */
5792 		max_sectors = mddev->resync_max_sectors;
5793 		mddev->resync_mismatches = 0;
5794 		/* we don't use the checkpoint if there's a bitmap */
5795 		if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
5796 			j = mddev->resync_min;
5797 		else if (!mddev->bitmap)
5798 			j = mddev->recovery_cp;
5799 
5800 	} else if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
5801 		max_sectors = mddev->size << 1;
5802 	else {
5803 		/* recovery follows the physical size of devices */
5804 		max_sectors = mddev->size << 1;
5805 		j = MaxSector;
5806 		rdev_for_each(rdev, rtmp, mddev)
5807 			if (rdev->raid_disk >= 0 &&
5808 			    !test_bit(Faulty, &rdev->flags) &&
5809 			    !test_bit(In_sync, &rdev->flags) &&
5810 			    rdev->recovery_offset < j)
5811 				j = rdev->recovery_offset;
5812 	}
5813 
5814 	printk(KERN_INFO "md: %s of RAID array %s\n", desc, mdname(mddev));
5815 	printk(KERN_INFO "md: minimum _guaranteed_  speed:"
5816 		" %d KB/sec/disk.\n", speed_min(mddev));
5817 	printk(KERN_INFO "md: using maximum available idle IO bandwidth "
5818 	       "(but not more than %d KB/sec) for %s.\n",
5819 	       speed_max(mddev), desc);
5820 
5821 	is_mddev_idle(mddev); /* this also initializes IO event counters */
5822 
5823 	io_sectors = 0;
5824 	for (m = 0; m < SYNC_MARKS; m++) {
5825 		mark[m] = jiffies;
5826 		mark_cnt[m] = io_sectors;
5827 	}
5828 	last_mark = 0;
5829 	mddev->resync_mark = mark[last_mark];
5830 	mddev->resync_mark_cnt = mark_cnt[last_mark];
5831 
5832 	/*
5833 	 * Tune reconstruction:
5834 	 */
5835 	window = 32*(PAGE_SIZE/512);
5836 	printk(KERN_INFO "md: using %dk window, over a total of %llu blocks.\n",
5837 		window/2,(unsigned long long) max_sectors/2);
5838 
5839 	atomic_set(&mddev->recovery_active, 0);
5840 	last_check = 0;
5841 
5842 	if (j>2) {
5843 		printk(KERN_INFO
5844 		       "md: resuming %s of %s from checkpoint.\n",
5845 		       desc, mdname(mddev));
5846 		mddev->curr_resync = j;
5847 	}
5848 
5849 	while (j < max_sectors) {
5850 		sector_t sectors;
5851 
5852 		skipped = 0;
5853 		if (j >= mddev->resync_max) {
5854 			sysfs_notify(&mddev->kobj, NULL, "sync_completed");
5855 			wait_event(mddev->recovery_wait,
5856 				   mddev->resync_max > j
5857 				   || kthread_should_stop());
5858 		}
5859 		if (kthread_should_stop())
5860 			goto interrupted;
5861 		sectors = mddev->pers->sync_request(mddev, j, &skipped,
5862 						  currspeed < speed_min(mddev));
5863 		if (sectors == 0) {
5864 			set_bit(MD_RECOVERY_INTR, &mddev->recovery);
5865 			goto out;
5866 		}
5867 
5868 		if (!skipped) { /* actual IO requested */
5869 			io_sectors += sectors;
5870 			atomic_add(sectors, &mddev->recovery_active);
5871 		}
5872 
5873 		j += sectors;
5874 		if (j>1) mddev->curr_resync = j;
5875 		mddev->curr_mark_cnt = io_sectors;
5876 		if (last_check == 0)
5877 			/* this is the earliers that rebuilt will be
5878 			 * visible in /proc/mdstat
5879 			 */
5880 			md_new_event(mddev);
5881 
5882 		if (last_check + window > io_sectors || j == max_sectors)
5883 			continue;
5884 
5885 		last_check = io_sectors;
5886 
5887 		if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
5888 			break;
5889 
5890 	repeat:
5891 		if (time_after_eq(jiffies, mark[last_mark] + SYNC_MARK_STEP )) {
5892 			/* step marks */
5893 			int next = (last_mark+1) % SYNC_MARKS;
5894 
5895 			mddev->resync_mark = mark[next];
5896 			mddev->resync_mark_cnt = mark_cnt[next];
5897 			mark[next] = jiffies;
5898 			mark_cnt[next] = io_sectors - atomic_read(&mddev->recovery_active);
5899 			last_mark = next;
5900 		}
5901 
5902 
5903 		if (kthread_should_stop())
5904 			goto interrupted;
5905 
5906 
5907 		/*
5908 		 * this loop exits only if either when we are slower than
5909 		 * the 'hard' speed limit, or the system was IO-idle for
5910 		 * a jiffy.
5911 		 * the system might be non-idle CPU-wise, but we only care
5912 		 * about not overloading the IO subsystem. (things like an
5913 		 * e2fsck being done on the RAID array should execute fast)
5914 		 */
5915 		blk_unplug(mddev->queue);
5916 		cond_resched();
5917 
5918 		currspeed = ((unsigned long)(io_sectors-mddev->resync_mark_cnt))/2
5919 			/((jiffies-mddev->resync_mark)/HZ +1) +1;
5920 
5921 		if (currspeed > speed_min(mddev)) {
5922 			if ((currspeed > speed_max(mddev)) ||
5923 					!is_mddev_idle(mddev)) {
5924 				msleep(500);
5925 				goto repeat;
5926 			}
5927 		}
5928 	}
5929 	printk(KERN_INFO "md: %s: %s done.\n",mdname(mddev), desc);
5930 	/*
5931 	 * this also signals 'finished resyncing' to md_stop
5932 	 */
5933  out:
5934 	blk_unplug(mddev->queue);
5935 
5936 	wait_event(mddev->recovery_wait, !atomic_read(&mddev->recovery_active));
5937 
5938 	/* tell personality that we are finished */
5939 	mddev->pers->sync_request(mddev, max_sectors, &skipped, 1);
5940 
5941 	if (!test_bit(MD_RECOVERY_CHECK, &mddev->recovery) &&
5942 	    mddev->curr_resync > 2) {
5943 		if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
5944 			if (test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
5945 				if (mddev->curr_resync >= mddev->recovery_cp) {
5946 					printk(KERN_INFO
5947 					       "md: checkpointing %s of %s.\n",
5948 					       desc, mdname(mddev));
5949 					mddev->recovery_cp = mddev->curr_resync;
5950 				}
5951 			} else
5952 				mddev->recovery_cp = MaxSector;
5953 		} else {
5954 			if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery))
5955 				mddev->curr_resync = MaxSector;
5956 			rdev_for_each(rdev, rtmp, mddev)
5957 				if (rdev->raid_disk >= 0 &&
5958 				    !test_bit(Faulty, &rdev->flags) &&
5959 				    !test_bit(In_sync, &rdev->flags) &&
5960 				    rdev->recovery_offset < mddev->curr_resync)
5961 					rdev->recovery_offset = mddev->curr_resync;
5962 		}
5963 	}
5964 	set_bit(MD_CHANGE_DEVS, &mddev->flags);
5965 
5966  skip:
5967 	mddev->curr_resync = 0;
5968 	mddev->resync_min = 0;
5969 	mddev->resync_max = MaxSector;
5970 	sysfs_notify(&mddev->kobj, NULL, "sync_completed");
5971 	wake_up(&resync_wait);
5972 	set_bit(MD_RECOVERY_DONE, &mddev->recovery);
5973 	md_wakeup_thread(mddev->thread);
5974 	return;
5975 
5976  interrupted:
5977 	/*
5978 	 * got a signal, exit.
5979 	 */
5980 	printk(KERN_INFO
5981 	       "md: md_do_sync() got signal ... exiting\n");
5982 	set_bit(MD_RECOVERY_INTR, &mddev->recovery);
5983 	goto out;
5984 
5985 }
5986 EXPORT_SYMBOL_GPL(md_do_sync);
5987 
5988 
5989 static int remove_and_add_spares(mddev_t *mddev)
5990 {
5991 	mdk_rdev_t *rdev;
5992 	struct list_head *rtmp;
5993 	int spares = 0;
5994 
5995 	rdev_for_each(rdev, rtmp, mddev)
5996 		if (rdev->raid_disk >= 0 &&
5997 		    !test_bit(Blocked, &rdev->flags) &&
5998 		    (test_bit(Faulty, &rdev->flags) ||
5999 		     ! test_bit(In_sync, &rdev->flags)) &&
6000 		    atomic_read(&rdev->nr_pending)==0) {
6001 			if (mddev->pers->hot_remove_disk(
6002 				    mddev, rdev->raid_disk)==0) {
6003 				char nm[20];
6004 				sprintf(nm,"rd%d", rdev->raid_disk);
6005 				sysfs_remove_link(&mddev->kobj, nm);
6006 				rdev->raid_disk = -1;
6007 			}
6008 		}
6009 
6010 	if (mddev->degraded && ! mddev->ro) {
6011 		rdev_for_each(rdev, rtmp, mddev) {
6012 			if (rdev->raid_disk >= 0 &&
6013 			    !test_bit(In_sync, &rdev->flags) &&
6014 			    !test_bit(Blocked, &rdev->flags))
6015 				spares++;
6016 			if (rdev->raid_disk < 0
6017 			    && !test_bit(Faulty, &rdev->flags)) {
6018 				rdev->recovery_offset = 0;
6019 				if (mddev->pers->
6020 				    hot_add_disk(mddev, rdev) == 0) {
6021 					char nm[20];
6022 					sprintf(nm, "rd%d", rdev->raid_disk);
6023 					if (sysfs_create_link(&mddev->kobj,
6024 							      &rdev->kobj, nm))
6025 						printk(KERN_WARNING
6026 						       "md: cannot register "
6027 						       "%s for %s\n",
6028 						       nm, mdname(mddev));
6029 					spares++;
6030 					md_new_event(mddev);
6031 				} else
6032 					break;
6033 			}
6034 		}
6035 	}
6036 	return spares;
6037 }
6038 /*
6039  * This routine is regularly called by all per-raid-array threads to
6040  * deal with generic issues like resync and super-block update.
6041  * Raid personalities that don't have a thread (linear/raid0) do not
6042  * need this as they never do any recovery or update the superblock.
6043  *
6044  * It does not do any resync itself, but rather "forks" off other threads
6045  * to do that as needed.
6046  * When it is determined that resync is needed, we set MD_RECOVERY_RUNNING in
6047  * "->recovery" and create a thread at ->sync_thread.
6048  * When the thread finishes it sets MD_RECOVERY_DONE
6049  * and wakeups up this thread which will reap the thread and finish up.
6050  * This thread also removes any faulty devices (with nr_pending == 0).
6051  *
6052  * The overall approach is:
6053  *  1/ if the superblock needs updating, update it.
6054  *  2/ If a recovery thread is running, don't do anything else.
6055  *  3/ If recovery has finished, clean up, possibly marking spares active.
6056  *  4/ If there are any faulty devices, remove them.
6057  *  5/ If array is degraded, try to add spares devices
6058  *  6/ If array has spares or is not in-sync, start a resync thread.
6059  */
6060 void md_check_recovery(mddev_t *mddev)
6061 {
6062 	mdk_rdev_t *rdev;
6063 	struct list_head *rtmp;
6064 
6065 
6066 	if (mddev->bitmap)
6067 		bitmap_daemon_work(mddev->bitmap);
6068 
6069 	if (test_and_clear_bit(MD_NOTIFY_ARRAY_STATE, &mddev->flags))
6070 		sysfs_notify(&mddev->kobj, NULL, "array_state");
6071 
6072 	if (mddev->ro)
6073 		return;
6074 
6075 	if (signal_pending(current)) {
6076 		if (mddev->pers->sync_request && !mddev->external) {
6077 			printk(KERN_INFO "md: %s in immediate safe mode\n",
6078 			       mdname(mddev));
6079 			mddev->safemode = 2;
6080 		}
6081 		flush_signals(current);
6082 	}
6083 
6084 	if (mddev->ro && !test_bit(MD_RECOVERY_NEEDED, &mddev->recovery))
6085 		return;
6086 	if ( ! (
6087 		(mddev->flags && !mddev->external) ||
6088 		test_bit(MD_RECOVERY_NEEDED, &mddev->recovery) ||
6089 		test_bit(MD_RECOVERY_DONE, &mddev->recovery) ||
6090 		(mddev->external == 0 && mddev->safemode == 1) ||
6091 		(mddev->safemode == 2 && ! atomic_read(&mddev->writes_pending)
6092 		 && !mddev->in_sync && mddev->recovery_cp == MaxSector)
6093 		))
6094 		return;
6095 
6096 	if (mddev_trylock(mddev)) {
6097 		int spares = 0;
6098 
6099 		if (mddev->ro) {
6100 			/* Only thing we do on a ro array is remove
6101 			 * failed devices.
6102 			 */
6103 			remove_and_add_spares(mddev);
6104 			clear_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
6105 			goto unlock;
6106 		}
6107 
6108 		if (!mddev->external) {
6109 			int did_change = 0;
6110 			spin_lock_irq(&mddev->write_lock);
6111 			if (mddev->safemode &&
6112 			    !atomic_read(&mddev->writes_pending) &&
6113 			    !mddev->in_sync &&
6114 			    mddev->recovery_cp == MaxSector) {
6115 				mddev->in_sync = 1;
6116 				did_change = 1;
6117 				if (mddev->persistent)
6118 					set_bit(MD_CHANGE_CLEAN, &mddev->flags);
6119 			}
6120 			if (mddev->safemode == 1)
6121 				mddev->safemode = 0;
6122 			spin_unlock_irq(&mddev->write_lock);
6123 			if (did_change)
6124 				sysfs_notify(&mddev->kobj, NULL, "array_state");
6125 		}
6126 
6127 		if (mddev->flags)
6128 			md_update_sb(mddev, 0);
6129 
6130 		rdev_for_each(rdev, rtmp, mddev)
6131 			if (test_and_clear_bit(StateChanged, &rdev->flags))
6132 				sysfs_notify(&rdev->kobj, NULL, "state");
6133 
6134 
6135 		if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) &&
6136 		    !test_bit(MD_RECOVERY_DONE, &mddev->recovery)) {
6137 			/* resync/recovery still happening */
6138 			clear_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
6139 			goto unlock;
6140 		}
6141 		if (mddev->sync_thread) {
6142 			/* resync has finished, collect result */
6143 			md_unregister_thread(mddev->sync_thread);
6144 			mddev->sync_thread = NULL;
6145 			if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery) &&
6146 			    !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
6147 				/* success...*/
6148 				/* activate any spares */
6149 				if (mddev->pers->spare_active(mddev))
6150 					sysfs_notify(&mddev->kobj, NULL,
6151 						     "degraded");
6152 			}
6153 			md_update_sb(mddev, 1);
6154 
6155 			/* if array is no-longer degraded, then any saved_raid_disk
6156 			 * information must be scrapped
6157 			 */
6158 			if (!mddev->degraded)
6159 				rdev_for_each(rdev, rtmp, mddev)
6160 					rdev->saved_raid_disk = -1;
6161 
6162 			mddev->recovery = 0;
6163 			/* flag recovery needed just to double check */
6164 			set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
6165 			sysfs_notify(&mddev->kobj, NULL, "sync_action");
6166 			md_new_event(mddev);
6167 			goto unlock;
6168 		}
6169 		/* Set RUNNING before clearing NEEDED to avoid
6170 		 * any transients in the value of "sync_action".
6171 		 */
6172 		set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
6173 		clear_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
6174 		/* Clear some bits that don't mean anything, but
6175 		 * might be left set
6176 		 */
6177 		clear_bit(MD_RECOVERY_INTR, &mddev->recovery);
6178 		clear_bit(MD_RECOVERY_DONE, &mddev->recovery);
6179 
6180 		if (test_bit(MD_RECOVERY_FROZEN, &mddev->recovery))
6181 			goto unlock;
6182 		/* no recovery is running.
6183 		 * remove any failed drives, then
6184 		 * add spares if possible.
6185 		 * Spare are also removed and re-added, to allow
6186 		 * the personality to fail the re-add.
6187 		 */
6188 
6189 		if (mddev->reshape_position != MaxSector) {
6190 			if (mddev->pers->check_reshape(mddev) != 0)
6191 				/* Cannot proceed */
6192 				goto unlock;
6193 			set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
6194 			clear_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
6195 		} else if ((spares = remove_and_add_spares(mddev))) {
6196 			clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
6197 			clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
6198 			clear_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
6199 			set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
6200 		} else if (mddev->recovery_cp < MaxSector) {
6201 			set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
6202 			clear_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
6203 		} else if (!test_bit(MD_RECOVERY_SYNC, &mddev->recovery))
6204 			/* nothing to be done ... */
6205 			goto unlock;
6206 
6207 		if (mddev->pers->sync_request) {
6208 			if (spares && mddev->bitmap && ! mddev->bitmap->file) {
6209 				/* We are adding a device or devices to an array
6210 				 * which has the bitmap stored on all devices.
6211 				 * So make sure all bitmap pages get written
6212 				 */
6213 				bitmap_write_all(mddev->bitmap);
6214 			}
6215 			mddev->sync_thread = md_register_thread(md_do_sync,
6216 								mddev,
6217 								"%s_resync");
6218 			if (!mddev->sync_thread) {
6219 				printk(KERN_ERR "%s: could not start resync"
6220 					" thread...\n",
6221 					mdname(mddev));
6222 				/* leave the spares where they are, it shouldn't hurt */
6223 				mddev->recovery = 0;
6224 			} else
6225 				md_wakeup_thread(mddev->sync_thread);
6226 			sysfs_notify(&mddev->kobj, NULL, "sync_action");
6227 			md_new_event(mddev);
6228 		}
6229 	unlock:
6230 		if (!mddev->sync_thread) {
6231 			clear_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
6232 			if (test_and_clear_bit(MD_RECOVERY_RECOVER,
6233 					       &mddev->recovery))
6234 				sysfs_notify(&mddev->kobj, NULL, "sync_action");
6235 		}
6236 		mddev_unlock(mddev);
6237 	}
6238 }
6239 
6240 void md_wait_for_blocked_rdev(mdk_rdev_t *rdev, mddev_t *mddev)
6241 {
6242 	sysfs_notify(&rdev->kobj, NULL, "state");
6243 	wait_event_timeout(rdev->blocked_wait,
6244 			   !test_bit(Blocked, &rdev->flags),
6245 			   msecs_to_jiffies(5000));
6246 	rdev_dec_pending(rdev, mddev);
6247 }
6248 EXPORT_SYMBOL(md_wait_for_blocked_rdev);
6249 
6250 static int md_notify_reboot(struct notifier_block *this,
6251 			    unsigned long code, void *x)
6252 {
6253 	struct list_head *tmp;
6254 	mddev_t *mddev;
6255 
6256 	if ((code == SYS_DOWN) || (code == SYS_HALT) || (code == SYS_POWER_OFF)) {
6257 
6258 		printk(KERN_INFO "md: stopping all md devices.\n");
6259 
6260 		for_each_mddev(mddev, tmp)
6261 			if (mddev_trylock(mddev)) {
6262 				/* Force a switch to readonly even array
6263 				 * appears to still be in use.  Hence
6264 				 * the '100'.
6265 				 */
6266 				do_md_stop (mddev, 1, 100);
6267 				mddev_unlock(mddev);
6268 			}
6269 		/*
6270 		 * certain more exotic SCSI devices are known to be
6271 		 * volatile wrt too early system reboots. While the
6272 		 * right place to handle this issue is the given
6273 		 * driver, we do want to have a safe RAID driver ...
6274 		 */
6275 		mdelay(1000*1);
6276 	}
6277 	return NOTIFY_DONE;
6278 }
6279 
6280 static struct notifier_block md_notifier = {
6281 	.notifier_call	= md_notify_reboot,
6282 	.next		= NULL,
6283 	.priority	= INT_MAX, /* before any real devices */
6284 };
6285 
6286 static void md_geninit(void)
6287 {
6288 	dprintk("md: sizeof(mdp_super_t) = %d\n", (int)sizeof(mdp_super_t));
6289 
6290 	proc_create("mdstat", S_IRUGO, NULL, &md_seq_fops);
6291 }
6292 
6293 static int __init md_init(void)
6294 {
6295 	if (register_blkdev(MAJOR_NR, "md"))
6296 		return -1;
6297 	if ((mdp_major=register_blkdev(0, "mdp"))<=0) {
6298 		unregister_blkdev(MAJOR_NR, "md");
6299 		return -1;
6300 	}
6301 	blk_register_region(MKDEV(MAJOR_NR, 0), 1UL<<MINORBITS, THIS_MODULE,
6302 			    md_probe, NULL, NULL);
6303 	blk_register_region(MKDEV(mdp_major, 0), 1UL<<MINORBITS, THIS_MODULE,
6304 			    md_probe, NULL, NULL);
6305 
6306 	register_reboot_notifier(&md_notifier);
6307 	raid_table_header = register_sysctl_table(raid_root_table);
6308 
6309 	md_geninit();
6310 	return (0);
6311 }
6312 
6313 
6314 #ifndef MODULE
6315 
6316 /*
6317  * Searches all registered partitions for autorun RAID arrays
6318  * at boot time.
6319  */
6320 
6321 static LIST_HEAD(all_detected_devices);
6322 struct detected_devices_node {
6323 	struct list_head list;
6324 	dev_t dev;
6325 };
6326 
6327 void md_autodetect_dev(dev_t dev)
6328 {
6329 	struct detected_devices_node *node_detected_dev;
6330 
6331 	node_detected_dev = kzalloc(sizeof(*node_detected_dev), GFP_KERNEL);
6332 	if (node_detected_dev) {
6333 		node_detected_dev->dev = dev;
6334 		list_add_tail(&node_detected_dev->list, &all_detected_devices);
6335 	} else {
6336 		printk(KERN_CRIT "md: md_autodetect_dev: kzalloc failed"
6337 			", skipping dev(%d,%d)\n", MAJOR(dev), MINOR(dev));
6338 	}
6339 }
6340 
6341 
6342 static void autostart_arrays(int part)
6343 {
6344 	mdk_rdev_t *rdev;
6345 	struct detected_devices_node *node_detected_dev;
6346 	dev_t dev;
6347 	int i_scanned, i_passed;
6348 
6349 	i_scanned = 0;
6350 	i_passed = 0;
6351 
6352 	printk(KERN_INFO "md: Autodetecting RAID arrays.\n");
6353 
6354 	while (!list_empty(&all_detected_devices) && i_scanned < INT_MAX) {
6355 		i_scanned++;
6356 		node_detected_dev = list_entry(all_detected_devices.next,
6357 					struct detected_devices_node, list);
6358 		list_del(&node_detected_dev->list);
6359 		dev = node_detected_dev->dev;
6360 		kfree(node_detected_dev);
6361 		rdev = md_import_device(dev,0, 90);
6362 		if (IS_ERR(rdev))
6363 			continue;
6364 
6365 		if (test_bit(Faulty, &rdev->flags)) {
6366 			MD_BUG();
6367 			continue;
6368 		}
6369 		set_bit(AutoDetected, &rdev->flags);
6370 		list_add(&rdev->same_set, &pending_raid_disks);
6371 		i_passed++;
6372 	}
6373 
6374 	printk(KERN_INFO "md: Scanned %d and added %d devices.\n",
6375 						i_scanned, i_passed);
6376 
6377 	autorun_devices(part);
6378 }
6379 
6380 #endif /* !MODULE */
6381 
6382 static __exit void md_exit(void)
6383 {
6384 	mddev_t *mddev;
6385 	struct list_head *tmp;
6386 
6387 	blk_unregister_region(MKDEV(MAJOR_NR,0), 1U << MINORBITS);
6388 	blk_unregister_region(MKDEV(mdp_major,0), 1U << MINORBITS);
6389 
6390 	unregister_blkdev(MAJOR_NR,"md");
6391 	unregister_blkdev(mdp_major, "mdp");
6392 	unregister_reboot_notifier(&md_notifier);
6393 	unregister_sysctl_table(raid_table_header);
6394 	remove_proc_entry("mdstat", NULL);
6395 	for_each_mddev(mddev, tmp) {
6396 		struct gendisk *disk = mddev->gendisk;
6397 		if (!disk)
6398 			continue;
6399 		export_array(mddev);
6400 		del_gendisk(disk);
6401 		put_disk(disk);
6402 		mddev->gendisk = NULL;
6403 		mddev_put(mddev);
6404 	}
6405 }
6406 
6407 subsys_initcall(md_init);
6408 module_exit(md_exit)
6409 
6410 static int get_ro(char *buffer, struct kernel_param *kp)
6411 {
6412 	return sprintf(buffer, "%d", start_readonly);
6413 }
6414 static int set_ro(const char *val, struct kernel_param *kp)
6415 {
6416 	char *e;
6417 	int num = simple_strtoul(val, &e, 10);
6418 	if (*val && (*e == '\0' || *e == '\n')) {
6419 		start_readonly = num;
6420 		return 0;
6421 	}
6422 	return -EINVAL;
6423 }
6424 
6425 module_param_call(start_ro, set_ro, get_ro, NULL, S_IRUSR|S_IWUSR);
6426 module_param(start_dirty_degraded, int, S_IRUGO|S_IWUSR);
6427 
6428 
6429 EXPORT_SYMBOL(register_md_personality);
6430 EXPORT_SYMBOL(unregister_md_personality);
6431 EXPORT_SYMBOL(md_error);
6432 EXPORT_SYMBOL(md_done_sync);
6433 EXPORT_SYMBOL(md_write_start);
6434 EXPORT_SYMBOL(md_write_end);
6435 EXPORT_SYMBOL(md_register_thread);
6436 EXPORT_SYMBOL(md_unregister_thread);
6437 EXPORT_SYMBOL(md_wakeup_thread);
6438 EXPORT_SYMBOL(md_check_recovery);
6439 MODULE_LICENSE("GPL");
6440 MODULE_ALIAS("md");
6441 MODULE_ALIAS_BLOCKDEV_MAJOR(MD_MAJOR);
6442