xref: /linux/drivers/md/md.c (revision d89dffa976bcd13fd87eb76e02e3b71c3a7868e3)
1 /*
2    md.c : Multiple Devices driver for Linux
3 	  Copyright (C) 1998, 1999, 2000 Ingo Molnar
4 
5      completely rewritten, based on the MD driver code from Marc Zyngier
6 
7    Changes:
8 
9    - RAID-1/RAID-5 extensions by Miguel de Icaza, Gadi Oxman, Ingo Molnar
10    - RAID-6 extensions by H. Peter Anvin <hpa@zytor.com>
11    - boot support for linear and striped mode by Harald Hoyer <HarryH@Royal.Net>
12    - kerneld support by Boris Tobotras <boris@xtalk.msk.su>
13    - kmod support by: Cyrus Durgin
14    - RAID0 bugfixes: Mark Anthony Lisher <markal@iname.com>
15    - Devfs support by Richard Gooch <rgooch@atnf.csiro.au>
16 
17    - lots of fixes and improvements to the RAID1/RAID5 and generic
18      RAID code (such as request based resynchronization):
19 
20      Neil Brown <neilb@cse.unsw.edu.au>.
21 
22    - persistent bitmap code
23      Copyright (C) 2003-2004, Paul Clements, SteelEye Technology, Inc.
24 
25    This program is free software; you can redistribute it and/or modify
26    it under the terms of the GNU General Public License as published by
27    the Free Software Foundation; either version 2, or (at your option)
28    any later version.
29 
30    You should have received a copy of the GNU General Public License
31    (for example /usr/src/linux/COPYING); if not, write to the Free
32    Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
33 */
34 
35 #include <linux/kthread.h>
36 #include <linux/blkdev.h>
37 #include <linux/sysctl.h>
38 #include <linux/seq_file.h>
39 #include <linux/fs.h>
40 #include <linux/poll.h>
41 #include <linux/ctype.h>
42 #include <linux/string.h>
43 #include <linux/hdreg.h>
44 #include <linux/proc_fs.h>
45 #include <linux/random.h>
46 #include <linux/module.h>
47 #include <linux/reboot.h>
48 #include <linux/file.h>
49 #include <linux/compat.h>
50 #include <linux/delay.h>
51 #include <linux/raid/md_p.h>
52 #include <linux/raid/md_u.h>
53 #include <linux/slab.h>
54 #include "md.h"
55 #include "bitmap.h"
56 
57 #ifndef MODULE
58 static void autostart_arrays(int part);
59 #endif
60 
61 /* pers_list is a list of registered personalities protected
62  * by pers_lock.
63  * pers_lock does extra service to protect accesses to
64  * mddev->thread when the mutex cannot be held.
65  */
66 static LIST_HEAD(pers_list);
67 static DEFINE_SPINLOCK(pers_lock);
68 
69 static void md_print_devices(void);
70 
71 static DECLARE_WAIT_QUEUE_HEAD(resync_wait);
72 static struct workqueue_struct *md_wq;
73 static struct workqueue_struct *md_misc_wq;
74 
75 #define MD_BUG(x...) { printk("md: bug in file %s, line %d\n", __FILE__, __LINE__); md_print_devices(); }
76 
77 /*
78  * Default number of read corrections we'll attempt on an rdev
79  * before ejecting it from the array. We divide the read error
80  * count by 2 for every hour elapsed between read errors.
81  */
82 #define MD_DEFAULT_MAX_CORRECTED_READ_ERRORS 20
83 /*
84  * Current RAID-1,4,5 parallel reconstruction 'guaranteed speed limit'
85  * is 1000 KB/sec, so the extra system load does not show up that much.
86  * Increase it if you want to have more _guaranteed_ speed. Note that
87  * the RAID driver will use the maximum available bandwidth if the IO
88  * subsystem is idle. There is also an 'absolute maximum' reconstruction
89  * speed limit - in case reconstruction slows down your system despite
90  * idle IO detection.
91  *
92  * you can change it via /proc/sys/dev/raid/speed_limit_min and _max.
93  * or /sys/block/mdX/md/sync_speed_{min,max}
94  */
95 
96 static int sysctl_speed_limit_min = 1000;
97 static int sysctl_speed_limit_max = 200000;
98 static inline int speed_min(struct mddev *mddev)
99 {
100 	return mddev->sync_speed_min ?
101 		mddev->sync_speed_min : sysctl_speed_limit_min;
102 }
103 
104 static inline int speed_max(struct mddev *mddev)
105 {
106 	return mddev->sync_speed_max ?
107 		mddev->sync_speed_max : sysctl_speed_limit_max;
108 }
109 
110 static struct ctl_table_header *raid_table_header;
111 
112 static ctl_table raid_table[] = {
113 	{
114 		.procname	= "speed_limit_min",
115 		.data		= &sysctl_speed_limit_min,
116 		.maxlen		= sizeof(int),
117 		.mode		= S_IRUGO|S_IWUSR,
118 		.proc_handler	= proc_dointvec,
119 	},
120 	{
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 	{ }
128 };
129 
130 static ctl_table raid_dir_table[] = {
131 	{
132 		.procname	= "raid",
133 		.maxlen		= 0,
134 		.mode		= S_IRUGO|S_IXUGO,
135 		.child		= raid_table,
136 	},
137 	{ }
138 };
139 
140 static ctl_table raid_root_table[] = {
141 	{
142 		.procname	= "dev",
143 		.maxlen		= 0,
144 		.mode		= 0555,
145 		.child		= raid_dir_table,
146 	},
147 	{  }
148 };
149 
150 static const struct block_device_operations md_fops;
151 
152 static int start_readonly;
153 
154 /* bio_clone_mddev
155  * like bio_clone, but with a local bio set
156  */
157 
158 static void mddev_bio_destructor(struct bio *bio)
159 {
160 	struct mddev *mddev, **mddevp;
161 
162 	mddevp = (void*)bio;
163 	mddev = mddevp[-1];
164 
165 	bio_free(bio, mddev->bio_set);
166 }
167 
168 struct bio *bio_alloc_mddev(gfp_t gfp_mask, int nr_iovecs,
169 			    struct mddev *mddev)
170 {
171 	struct bio *b;
172 	struct mddev **mddevp;
173 
174 	if (!mddev || !mddev->bio_set)
175 		return bio_alloc(gfp_mask, nr_iovecs);
176 
177 	b = bio_alloc_bioset(gfp_mask, nr_iovecs,
178 			     mddev->bio_set);
179 	if (!b)
180 		return NULL;
181 	mddevp = (void*)b;
182 	mddevp[-1] = mddev;
183 	b->bi_destructor = mddev_bio_destructor;
184 	return b;
185 }
186 EXPORT_SYMBOL_GPL(bio_alloc_mddev);
187 
188 struct bio *bio_clone_mddev(struct bio *bio, gfp_t gfp_mask,
189 			    struct mddev *mddev)
190 {
191 	struct bio *b;
192 	struct mddev **mddevp;
193 
194 	if (!mddev || !mddev->bio_set)
195 		return bio_clone(bio, gfp_mask);
196 
197 	b = bio_alloc_bioset(gfp_mask, bio->bi_max_vecs,
198 			     mddev->bio_set);
199 	if (!b)
200 		return NULL;
201 	mddevp = (void*)b;
202 	mddevp[-1] = mddev;
203 	b->bi_destructor = mddev_bio_destructor;
204 	__bio_clone(b, bio);
205 	if (bio_integrity(bio)) {
206 		int ret;
207 
208 		ret = bio_integrity_clone(b, bio, gfp_mask, mddev->bio_set);
209 
210 		if (ret < 0) {
211 			bio_put(b);
212 			return NULL;
213 		}
214 	}
215 
216 	return b;
217 }
218 EXPORT_SYMBOL_GPL(bio_clone_mddev);
219 
220 void md_trim_bio(struct bio *bio, int offset, int size)
221 {
222 	/* 'bio' is a cloned bio which we need to trim to match
223 	 * the given offset and size.
224 	 * This requires adjusting bi_sector, bi_size, and bi_io_vec
225 	 */
226 	int i;
227 	struct bio_vec *bvec;
228 	int sofar = 0;
229 
230 	size <<= 9;
231 	if (offset == 0 && size == bio->bi_size)
232 		return;
233 
234 	bio->bi_sector += offset;
235 	bio->bi_size = size;
236 	offset <<= 9;
237 	clear_bit(BIO_SEG_VALID, &bio->bi_flags);
238 
239 	while (bio->bi_idx < bio->bi_vcnt &&
240 	       bio->bi_io_vec[bio->bi_idx].bv_len <= offset) {
241 		/* remove this whole bio_vec */
242 		offset -= bio->bi_io_vec[bio->bi_idx].bv_len;
243 		bio->bi_idx++;
244 	}
245 	if (bio->bi_idx < bio->bi_vcnt) {
246 		bio->bi_io_vec[bio->bi_idx].bv_offset += offset;
247 		bio->bi_io_vec[bio->bi_idx].bv_len -= offset;
248 	}
249 	/* avoid any complications with bi_idx being non-zero*/
250 	if (bio->bi_idx) {
251 		memmove(bio->bi_io_vec, bio->bi_io_vec+bio->bi_idx,
252 			(bio->bi_vcnt - bio->bi_idx) * sizeof(struct bio_vec));
253 		bio->bi_vcnt -= bio->bi_idx;
254 		bio->bi_idx = 0;
255 	}
256 	/* Make sure vcnt and last bv are not too big */
257 	bio_for_each_segment(bvec, bio, i) {
258 		if (sofar + bvec->bv_len > size)
259 			bvec->bv_len = size - sofar;
260 		if (bvec->bv_len == 0) {
261 			bio->bi_vcnt = i;
262 			break;
263 		}
264 		sofar += bvec->bv_len;
265 	}
266 }
267 EXPORT_SYMBOL_GPL(md_trim_bio);
268 
269 /*
270  * We have a system wide 'event count' that is incremented
271  * on any 'interesting' event, and readers of /proc/mdstat
272  * can use 'poll' or 'select' to find out when the event
273  * count increases.
274  *
275  * Events are:
276  *  start array, stop array, error, add device, remove device,
277  *  start build, activate spare
278  */
279 static DECLARE_WAIT_QUEUE_HEAD(md_event_waiters);
280 static atomic_t md_event_count;
281 void md_new_event(struct mddev *mddev)
282 {
283 	atomic_inc(&md_event_count);
284 	wake_up(&md_event_waiters);
285 }
286 EXPORT_SYMBOL_GPL(md_new_event);
287 
288 /* Alternate version that can be called from interrupts
289  * when calling sysfs_notify isn't needed.
290  */
291 static void md_new_event_inintr(struct mddev *mddev)
292 {
293 	atomic_inc(&md_event_count);
294 	wake_up(&md_event_waiters);
295 }
296 
297 /*
298  * Enables to iterate over all existing md arrays
299  * all_mddevs_lock protects this list.
300  */
301 static LIST_HEAD(all_mddevs);
302 static DEFINE_SPINLOCK(all_mddevs_lock);
303 
304 
305 /*
306  * iterates through all used mddevs in the system.
307  * We take care to grab the all_mddevs_lock whenever navigating
308  * the list, and to always hold a refcount when unlocked.
309  * Any code which breaks out of this loop while own
310  * a reference to the current mddev and must mddev_put it.
311  */
312 #define for_each_mddev(_mddev,_tmp)					\
313 									\
314 	for (({ spin_lock(&all_mddevs_lock); 				\
315 		_tmp = all_mddevs.next;					\
316 		_mddev = NULL;});					\
317 	     ({ if (_tmp != &all_mddevs)				\
318 			mddev_get(list_entry(_tmp, struct mddev, all_mddevs));\
319 		spin_unlock(&all_mddevs_lock);				\
320 		if (_mddev) mddev_put(_mddev);				\
321 		_mddev = list_entry(_tmp, struct mddev, all_mddevs);	\
322 		_tmp != &all_mddevs;});					\
323 	     ({ spin_lock(&all_mddevs_lock);				\
324 		_tmp = _tmp->next;})					\
325 		)
326 
327 
328 /* Rather than calling directly into the personality make_request function,
329  * IO requests come here first so that we can check if the device is
330  * being suspended pending a reconfiguration.
331  * We hold a refcount over the call to ->make_request.  By the time that
332  * call has finished, the bio has been linked into some internal structure
333  * and so is visible to ->quiesce(), so we don't need the refcount any more.
334  */
335 static void md_make_request(struct request_queue *q, struct bio *bio)
336 {
337 	const int rw = bio_data_dir(bio);
338 	struct mddev *mddev = q->queuedata;
339 	int cpu;
340 	unsigned int sectors;
341 
342 	if (mddev == NULL || mddev->pers == NULL
343 	    || !mddev->ready) {
344 		bio_io_error(bio);
345 		return;
346 	}
347 	smp_rmb(); /* Ensure implications of  'active' are visible */
348 	rcu_read_lock();
349 	if (mddev->suspended) {
350 		DEFINE_WAIT(__wait);
351 		for (;;) {
352 			prepare_to_wait(&mddev->sb_wait, &__wait,
353 					TASK_UNINTERRUPTIBLE);
354 			if (!mddev->suspended)
355 				break;
356 			rcu_read_unlock();
357 			schedule();
358 			rcu_read_lock();
359 		}
360 		finish_wait(&mddev->sb_wait, &__wait);
361 	}
362 	atomic_inc(&mddev->active_io);
363 	rcu_read_unlock();
364 
365 	/*
366 	 * save the sectors now since our bio can
367 	 * go away inside make_request
368 	 */
369 	sectors = bio_sectors(bio);
370 	mddev->pers->make_request(mddev, bio);
371 
372 	cpu = part_stat_lock();
373 	part_stat_inc(cpu, &mddev->gendisk->part0, ios[rw]);
374 	part_stat_add(cpu, &mddev->gendisk->part0, sectors[rw], sectors);
375 	part_stat_unlock();
376 
377 	if (atomic_dec_and_test(&mddev->active_io) && mddev->suspended)
378 		wake_up(&mddev->sb_wait);
379 }
380 
381 /* mddev_suspend makes sure no new requests are submitted
382  * to the device, and that any requests that have been submitted
383  * are completely handled.
384  * Once ->stop is called and completes, the module will be completely
385  * unused.
386  */
387 void mddev_suspend(struct mddev *mddev)
388 {
389 	BUG_ON(mddev->suspended);
390 	mddev->suspended = 1;
391 	synchronize_rcu();
392 	wait_event(mddev->sb_wait, atomic_read(&mddev->active_io) == 0);
393 	mddev->pers->quiesce(mddev, 1);
394 
395 	del_timer_sync(&mddev->safemode_timer);
396 }
397 EXPORT_SYMBOL_GPL(mddev_suspend);
398 
399 void mddev_resume(struct mddev *mddev)
400 {
401 	mddev->suspended = 0;
402 	wake_up(&mddev->sb_wait);
403 	mddev->pers->quiesce(mddev, 0);
404 
405 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
406 	md_wakeup_thread(mddev->thread);
407 	md_wakeup_thread(mddev->sync_thread); /* possibly kick off a reshape */
408 }
409 EXPORT_SYMBOL_GPL(mddev_resume);
410 
411 int mddev_congested(struct mddev *mddev, int bits)
412 {
413 	return mddev->suspended;
414 }
415 EXPORT_SYMBOL(mddev_congested);
416 
417 /*
418  * Generic flush handling for md
419  */
420 
421 static void md_end_flush(struct bio *bio, int err)
422 {
423 	struct md_rdev *rdev = bio->bi_private;
424 	struct mddev *mddev = rdev->mddev;
425 
426 	rdev_dec_pending(rdev, mddev);
427 
428 	if (atomic_dec_and_test(&mddev->flush_pending)) {
429 		/* The pre-request flush has finished */
430 		queue_work(md_wq, &mddev->flush_work);
431 	}
432 	bio_put(bio);
433 }
434 
435 static void md_submit_flush_data(struct work_struct *ws);
436 
437 static void submit_flushes(struct work_struct *ws)
438 {
439 	struct mddev *mddev = container_of(ws, struct mddev, flush_work);
440 	struct md_rdev *rdev;
441 
442 	INIT_WORK(&mddev->flush_work, md_submit_flush_data);
443 	atomic_set(&mddev->flush_pending, 1);
444 	rcu_read_lock();
445 	rdev_for_each_rcu(rdev, mddev)
446 		if (rdev->raid_disk >= 0 &&
447 		    !test_bit(Faulty, &rdev->flags)) {
448 			/* Take two references, one is dropped
449 			 * when request finishes, one after
450 			 * we reclaim rcu_read_lock
451 			 */
452 			struct bio *bi;
453 			atomic_inc(&rdev->nr_pending);
454 			atomic_inc(&rdev->nr_pending);
455 			rcu_read_unlock();
456 			bi = bio_alloc_mddev(GFP_NOIO, 0, mddev);
457 			bi->bi_end_io = md_end_flush;
458 			bi->bi_private = rdev;
459 			bi->bi_bdev = rdev->bdev;
460 			atomic_inc(&mddev->flush_pending);
461 			submit_bio(WRITE_FLUSH, bi);
462 			rcu_read_lock();
463 			rdev_dec_pending(rdev, mddev);
464 		}
465 	rcu_read_unlock();
466 	if (atomic_dec_and_test(&mddev->flush_pending))
467 		queue_work(md_wq, &mddev->flush_work);
468 }
469 
470 static void md_submit_flush_data(struct work_struct *ws)
471 {
472 	struct mddev *mddev = container_of(ws, struct mddev, flush_work);
473 	struct bio *bio = mddev->flush_bio;
474 
475 	if (bio->bi_size == 0)
476 		/* an empty barrier - all done */
477 		bio_endio(bio, 0);
478 	else {
479 		bio->bi_rw &= ~REQ_FLUSH;
480 		mddev->pers->make_request(mddev, bio);
481 	}
482 
483 	mddev->flush_bio = NULL;
484 	wake_up(&mddev->sb_wait);
485 }
486 
487 void md_flush_request(struct mddev *mddev, struct bio *bio)
488 {
489 	spin_lock_irq(&mddev->write_lock);
490 	wait_event_lock_irq(mddev->sb_wait,
491 			    !mddev->flush_bio,
492 			    mddev->write_lock, /*nothing*/);
493 	mddev->flush_bio = bio;
494 	spin_unlock_irq(&mddev->write_lock);
495 
496 	INIT_WORK(&mddev->flush_work, submit_flushes);
497 	queue_work(md_wq, &mddev->flush_work);
498 }
499 EXPORT_SYMBOL(md_flush_request);
500 
501 /* Support for plugging.
502  * This mirrors the plugging support in request_queue, but does not
503  * require having a whole queue or request structures.
504  * We allocate an md_plug_cb for each md device and each thread it gets
505  * plugged on.  This links tot the private plug_handle structure in the
506  * personality data where we keep a count of the number of outstanding
507  * plugs so other code can see if a plug is active.
508  */
509 struct md_plug_cb {
510 	struct blk_plug_cb cb;
511 	struct mddev *mddev;
512 };
513 
514 static void plugger_unplug(struct blk_plug_cb *cb)
515 {
516 	struct md_plug_cb *mdcb = container_of(cb, struct md_plug_cb, cb);
517 	if (atomic_dec_and_test(&mdcb->mddev->plug_cnt))
518 		md_wakeup_thread(mdcb->mddev->thread);
519 	kfree(mdcb);
520 }
521 
522 /* Check that an unplug wakeup will come shortly.
523  * If not, wakeup the md thread immediately
524  */
525 int mddev_check_plugged(struct mddev *mddev)
526 {
527 	struct blk_plug *plug = current->plug;
528 	struct md_plug_cb *mdcb;
529 
530 	if (!plug)
531 		return 0;
532 
533 	list_for_each_entry(mdcb, &plug->cb_list, cb.list) {
534 		if (mdcb->cb.callback == plugger_unplug &&
535 		    mdcb->mddev == mddev) {
536 			/* Already on the list, move to top */
537 			if (mdcb != list_first_entry(&plug->cb_list,
538 						    struct md_plug_cb,
539 						    cb.list))
540 				list_move(&mdcb->cb.list, &plug->cb_list);
541 			return 1;
542 		}
543 	}
544 	/* Not currently on the callback list */
545 	mdcb = kmalloc(sizeof(*mdcb), GFP_ATOMIC);
546 	if (!mdcb)
547 		return 0;
548 
549 	mdcb->mddev = mddev;
550 	mdcb->cb.callback = plugger_unplug;
551 	atomic_inc(&mddev->plug_cnt);
552 	list_add(&mdcb->cb.list, &plug->cb_list);
553 	return 1;
554 }
555 EXPORT_SYMBOL_GPL(mddev_check_plugged);
556 
557 static inline struct mddev *mddev_get(struct mddev *mddev)
558 {
559 	atomic_inc(&mddev->active);
560 	return mddev;
561 }
562 
563 static void mddev_delayed_delete(struct work_struct *ws);
564 
565 static void mddev_put(struct mddev *mddev)
566 {
567 	struct bio_set *bs = NULL;
568 
569 	if (!atomic_dec_and_lock(&mddev->active, &all_mddevs_lock))
570 		return;
571 	if (!mddev->raid_disks && list_empty(&mddev->disks) &&
572 	    mddev->ctime == 0 && !mddev->hold_active) {
573 		/* Array is not configured at all, and not held active,
574 		 * so destroy it */
575 		list_del_init(&mddev->all_mddevs);
576 		bs = mddev->bio_set;
577 		mddev->bio_set = NULL;
578 		if (mddev->gendisk) {
579 			/* We did a probe so need to clean up.  Call
580 			 * queue_work inside the spinlock so that
581 			 * flush_workqueue() after mddev_find will
582 			 * succeed in waiting for the work to be done.
583 			 */
584 			INIT_WORK(&mddev->del_work, mddev_delayed_delete);
585 			queue_work(md_misc_wq, &mddev->del_work);
586 		} else
587 			kfree(mddev);
588 	}
589 	spin_unlock(&all_mddevs_lock);
590 	if (bs)
591 		bioset_free(bs);
592 }
593 
594 void mddev_init(struct mddev *mddev)
595 {
596 	mutex_init(&mddev->open_mutex);
597 	mutex_init(&mddev->reconfig_mutex);
598 	mutex_init(&mddev->bitmap_info.mutex);
599 	INIT_LIST_HEAD(&mddev->disks);
600 	INIT_LIST_HEAD(&mddev->all_mddevs);
601 	init_timer(&mddev->safemode_timer);
602 	atomic_set(&mddev->active, 1);
603 	atomic_set(&mddev->openers, 0);
604 	atomic_set(&mddev->active_io, 0);
605 	atomic_set(&mddev->plug_cnt, 0);
606 	spin_lock_init(&mddev->write_lock);
607 	atomic_set(&mddev->flush_pending, 0);
608 	init_waitqueue_head(&mddev->sb_wait);
609 	init_waitqueue_head(&mddev->recovery_wait);
610 	mddev->reshape_position = MaxSector;
611 	mddev->reshape_backwards = 0;
612 	mddev->resync_min = 0;
613 	mddev->resync_max = MaxSector;
614 	mddev->level = LEVEL_NONE;
615 }
616 EXPORT_SYMBOL_GPL(mddev_init);
617 
618 static struct mddev * mddev_find(dev_t unit)
619 {
620 	struct mddev *mddev, *new = NULL;
621 
622 	if (unit && MAJOR(unit) != MD_MAJOR)
623 		unit &= ~((1<<MdpMinorShift)-1);
624 
625  retry:
626 	spin_lock(&all_mddevs_lock);
627 
628 	if (unit) {
629 		list_for_each_entry(mddev, &all_mddevs, all_mddevs)
630 			if (mddev->unit == unit) {
631 				mddev_get(mddev);
632 				spin_unlock(&all_mddevs_lock);
633 				kfree(new);
634 				return mddev;
635 			}
636 
637 		if (new) {
638 			list_add(&new->all_mddevs, &all_mddevs);
639 			spin_unlock(&all_mddevs_lock);
640 			new->hold_active = UNTIL_IOCTL;
641 			return new;
642 		}
643 	} else if (new) {
644 		/* find an unused unit number */
645 		static int next_minor = 512;
646 		int start = next_minor;
647 		int is_free = 0;
648 		int dev = 0;
649 		while (!is_free) {
650 			dev = MKDEV(MD_MAJOR, next_minor);
651 			next_minor++;
652 			if (next_minor > MINORMASK)
653 				next_minor = 0;
654 			if (next_minor == start) {
655 				/* Oh dear, all in use. */
656 				spin_unlock(&all_mddevs_lock);
657 				kfree(new);
658 				return NULL;
659 			}
660 
661 			is_free = 1;
662 			list_for_each_entry(mddev, &all_mddevs, all_mddevs)
663 				if (mddev->unit == dev) {
664 					is_free = 0;
665 					break;
666 				}
667 		}
668 		new->unit = dev;
669 		new->md_minor = MINOR(dev);
670 		new->hold_active = UNTIL_STOP;
671 		list_add(&new->all_mddevs, &all_mddevs);
672 		spin_unlock(&all_mddevs_lock);
673 		return new;
674 	}
675 	spin_unlock(&all_mddevs_lock);
676 
677 	new = kzalloc(sizeof(*new), GFP_KERNEL);
678 	if (!new)
679 		return NULL;
680 
681 	new->unit = unit;
682 	if (MAJOR(unit) == MD_MAJOR)
683 		new->md_minor = MINOR(unit);
684 	else
685 		new->md_minor = MINOR(unit) >> MdpMinorShift;
686 
687 	mddev_init(new);
688 
689 	goto retry;
690 }
691 
692 static inline int mddev_lock(struct mddev * mddev)
693 {
694 	return mutex_lock_interruptible(&mddev->reconfig_mutex);
695 }
696 
697 static inline int mddev_is_locked(struct mddev *mddev)
698 {
699 	return mutex_is_locked(&mddev->reconfig_mutex);
700 }
701 
702 static inline int mddev_trylock(struct mddev * mddev)
703 {
704 	return mutex_trylock(&mddev->reconfig_mutex);
705 }
706 
707 static struct attribute_group md_redundancy_group;
708 
709 static void mddev_unlock(struct mddev * mddev)
710 {
711 	if (mddev->to_remove) {
712 		/* These cannot be removed under reconfig_mutex as
713 		 * an access to the files will try to take reconfig_mutex
714 		 * while holding the file unremovable, which leads to
715 		 * a deadlock.
716 		 * So hold set sysfs_active while the remove in happeing,
717 		 * and anything else which might set ->to_remove or my
718 		 * otherwise change the sysfs namespace will fail with
719 		 * -EBUSY if sysfs_active is still set.
720 		 * We set sysfs_active under reconfig_mutex and elsewhere
721 		 * test it under the same mutex to ensure its correct value
722 		 * is seen.
723 		 */
724 		struct attribute_group *to_remove = mddev->to_remove;
725 		mddev->to_remove = NULL;
726 		mddev->sysfs_active = 1;
727 		mutex_unlock(&mddev->reconfig_mutex);
728 
729 		if (mddev->kobj.sd) {
730 			if (to_remove != &md_redundancy_group)
731 				sysfs_remove_group(&mddev->kobj, to_remove);
732 			if (mddev->pers == NULL ||
733 			    mddev->pers->sync_request == NULL) {
734 				sysfs_remove_group(&mddev->kobj, &md_redundancy_group);
735 				if (mddev->sysfs_action)
736 					sysfs_put(mddev->sysfs_action);
737 				mddev->sysfs_action = NULL;
738 			}
739 		}
740 		mddev->sysfs_active = 0;
741 	} else
742 		mutex_unlock(&mddev->reconfig_mutex);
743 
744 	/* As we've dropped the mutex we need a spinlock to
745 	 * make sure the thread doesn't disappear
746 	 */
747 	spin_lock(&pers_lock);
748 	md_wakeup_thread(mddev->thread);
749 	spin_unlock(&pers_lock);
750 }
751 
752 static struct md_rdev * find_rdev_nr(struct mddev *mddev, int nr)
753 {
754 	struct md_rdev *rdev;
755 
756 	rdev_for_each(rdev, mddev)
757 		if (rdev->desc_nr == nr)
758 			return rdev;
759 
760 	return NULL;
761 }
762 
763 static struct md_rdev * find_rdev(struct mddev * mddev, dev_t dev)
764 {
765 	struct md_rdev *rdev;
766 
767 	rdev_for_each(rdev, mddev)
768 		if (rdev->bdev->bd_dev == dev)
769 			return rdev;
770 
771 	return NULL;
772 }
773 
774 static struct md_personality *find_pers(int level, char *clevel)
775 {
776 	struct md_personality *pers;
777 	list_for_each_entry(pers, &pers_list, list) {
778 		if (level != LEVEL_NONE && pers->level == level)
779 			return pers;
780 		if (strcmp(pers->name, clevel)==0)
781 			return pers;
782 	}
783 	return NULL;
784 }
785 
786 /* return the offset of the super block in 512byte sectors */
787 static inline sector_t calc_dev_sboffset(struct md_rdev *rdev)
788 {
789 	sector_t num_sectors = i_size_read(rdev->bdev->bd_inode) / 512;
790 	return MD_NEW_SIZE_SECTORS(num_sectors);
791 }
792 
793 static int alloc_disk_sb(struct md_rdev * rdev)
794 {
795 	if (rdev->sb_page)
796 		MD_BUG();
797 
798 	rdev->sb_page = alloc_page(GFP_KERNEL);
799 	if (!rdev->sb_page) {
800 		printk(KERN_ALERT "md: out of memory.\n");
801 		return -ENOMEM;
802 	}
803 
804 	return 0;
805 }
806 
807 void md_rdev_clear(struct md_rdev *rdev)
808 {
809 	if (rdev->sb_page) {
810 		put_page(rdev->sb_page);
811 		rdev->sb_loaded = 0;
812 		rdev->sb_page = NULL;
813 		rdev->sb_start = 0;
814 		rdev->sectors = 0;
815 	}
816 	if (rdev->bb_page) {
817 		put_page(rdev->bb_page);
818 		rdev->bb_page = NULL;
819 	}
820 	kfree(rdev->badblocks.page);
821 	rdev->badblocks.page = NULL;
822 }
823 EXPORT_SYMBOL_GPL(md_rdev_clear);
824 
825 static void super_written(struct bio *bio, int error)
826 {
827 	struct md_rdev *rdev = bio->bi_private;
828 	struct mddev *mddev = rdev->mddev;
829 
830 	if (error || !test_bit(BIO_UPTODATE, &bio->bi_flags)) {
831 		printk("md: super_written gets error=%d, uptodate=%d\n",
832 		       error, test_bit(BIO_UPTODATE, &bio->bi_flags));
833 		WARN_ON(test_bit(BIO_UPTODATE, &bio->bi_flags));
834 		md_error(mddev, rdev);
835 	}
836 
837 	if (atomic_dec_and_test(&mddev->pending_writes))
838 		wake_up(&mddev->sb_wait);
839 	bio_put(bio);
840 }
841 
842 void md_super_write(struct mddev *mddev, struct md_rdev *rdev,
843 		   sector_t sector, int size, struct page *page)
844 {
845 	/* write first size bytes of page to sector of rdev
846 	 * Increment mddev->pending_writes before returning
847 	 * and decrement it on completion, waking up sb_wait
848 	 * if zero is reached.
849 	 * If an error occurred, call md_error
850 	 */
851 	struct bio *bio = bio_alloc_mddev(GFP_NOIO, 1, mddev);
852 
853 	bio->bi_bdev = rdev->meta_bdev ? rdev->meta_bdev : rdev->bdev;
854 	bio->bi_sector = sector;
855 	bio_add_page(bio, page, size, 0);
856 	bio->bi_private = rdev;
857 	bio->bi_end_io = super_written;
858 
859 	atomic_inc(&mddev->pending_writes);
860 	submit_bio(WRITE_FLUSH_FUA, bio);
861 }
862 
863 void md_super_wait(struct mddev *mddev)
864 {
865 	/* wait for all superblock writes that were scheduled to complete */
866 	DEFINE_WAIT(wq);
867 	for(;;) {
868 		prepare_to_wait(&mddev->sb_wait, &wq, TASK_UNINTERRUPTIBLE);
869 		if (atomic_read(&mddev->pending_writes)==0)
870 			break;
871 		schedule();
872 	}
873 	finish_wait(&mddev->sb_wait, &wq);
874 }
875 
876 static void bi_complete(struct bio *bio, int error)
877 {
878 	complete((struct completion*)bio->bi_private);
879 }
880 
881 int sync_page_io(struct md_rdev *rdev, sector_t sector, int size,
882 		 struct page *page, int rw, bool metadata_op)
883 {
884 	struct bio *bio = bio_alloc_mddev(GFP_NOIO, 1, rdev->mddev);
885 	struct completion event;
886 	int ret;
887 
888 	rw |= REQ_SYNC;
889 
890 	bio->bi_bdev = (metadata_op && rdev->meta_bdev) ?
891 		rdev->meta_bdev : rdev->bdev;
892 	if (metadata_op)
893 		bio->bi_sector = sector + rdev->sb_start;
894 	else if (rdev->mddev->reshape_position != MaxSector &&
895 		 (rdev->mddev->reshape_backwards ==
896 		  (sector >= rdev->mddev->reshape_position)))
897 		bio->bi_sector = sector + rdev->new_data_offset;
898 	else
899 		bio->bi_sector = sector + rdev->data_offset;
900 	bio_add_page(bio, page, size, 0);
901 	init_completion(&event);
902 	bio->bi_private = &event;
903 	bio->bi_end_io = bi_complete;
904 	submit_bio(rw, bio);
905 	wait_for_completion(&event);
906 
907 	ret = test_bit(BIO_UPTODATE, &bio->bi_flags);
908 	bio_put(bio);
909 	return ret;
910 }
911 EXPORT_SYMBOL_GPL(sync_page_io);
912 
913 static int read_disk_sb(struct md_rdev * rdev, int size)
914 {
915 	char b[BDEVNAME_SIZE];
916 	if (!rdev->sb_page) {
917 		MD_BUG();
918 		return -EINVAL;
919 	}
920 	if (rdev->sb_loaded)
921 		return 0;
922 
923 
924 	if (!sync_page_io(rdev, 0, size, rdev->sb_page, READ, true))
925 		goto fail;
926 	rdev->sb_loaded = 1;
927 	return 0;
928 
929 fail:
930 	printk(KERN_WARNING "md: disabled device %s, could not read superblock.\n",
931 		bdevname(rdev->bdev,b));
932 	return -EINVAL;
933 }
934 
935 static int uuid_equal(mdp_super_t *sb1, mdp_super_t *sb2)
936 {
937 	return 	sb1->set_uuid0 == sb2->set_uuid0 &&
938 		sb1->set_uuid1 == sb2->set_uuid1 &&
939 		sb1->set_uuid2 == sb2->set_uuid2 &&
940 		sb1->set_uuid3 == sb2->set_uuid3;
941 }
942 
943 static int sb_equal(mdp_super_t *sb1, mdp_super_t *sb2)
944 {
945 	int ret;
946 	mdp_super_t *tmp1, *tmp2;
947 
948 	tmp1 = kmalloc(sizeof(*tmp1),GFP_KERNEL);
949 	tmp2 = kmalloc(sizeof(*tmp2),GFP_KERNEL);
950 
951 	if (!tmp1 || !tmp2) {
952 		ret = 0;
953 		printk(KERN_INFO "md.c sb_equal(): failed to allocate memory!\n");
954 		goto abort;
955 	}
956 
957 	*tmp1 = *sb1;
958 	*tmp2 = *sb2;
959 
960 	/*
961 	 * nr_disks is not constant
962 	 */
963 	tmp1->nr_disks = 0;
964 	tmp2->nr_disks = 0;
965 
966 	ret = (memcmp(tmp1, tmp2, MD_SB_GENERIC_CONSTANT_WORDS * 4) == 0);
967 abort:
968 	kfree(tmp1);
969 	kfree(tmp2);
970 	return ret;
971 }
972 
973 
974 static u32 md_csum_fold(u32 csum)
975 {
976 	csum = (csum & 0xffff) + (csum >> 16);
977 	return (csum & 0xffff) + (csum >> 16);
978 }
979 
980 static unsigned int calc_sb_csum(mdp_super_t * sb)
981 {
982 	u64 newcsum = 0;
983 	u32 *sb32 = (u32*)sb;
984 	int i;
985 	unsigned int disk_csum, csum;
986 
987 	disk_csum = sb->sb_csum;
988 	sb->sb_csum = 0;
989 
990 	for (i = 0; i < MD_SB_BYTES/4 ; i++)
991 		newcsum += sb32[i];
992 	csum = (newcsum & 0xffffffff) + (newcsum>>32);
993 
994 
995 #ifdef CONFIG_ALPHA
996 	/* This used to use csum_partial, which was wrong for several
997 	 * reasons including that different results are returned on
998 	 * different architectures.  It isn't critical that we get exactly
999 	 * the same return value as before (we always csum_fold before
1000 	 * testing, and that removes any differences).  However as we
1001 	 * know that csum_partial always returned a 16bit value on
1002 	 * alphas, do a fold to maximise conformity to previous behaviour.
1003 	 */
1004 	sb->sb_csum = md_csum_fold(disk_csum);
1005 #else
1006 	sb->sb_csum = disk_csum;
1007 #endif
1008 	return csum;
1009 }
1010 
1011 
1012 /*
1013  * Handle superblock details.
1014  * We want to be able to handle multiple superblock formats
1015  * so we have a common interface to them all, and an array of
1016  * different handlers.
1017  * We rely on user-space to write the initial superblock, and support
1018  * reading and updating of superblocks.
1019  * Interface methods are:
1020  *   int load_super(struct md_rdev *dev, struct md_rdev *refdev, int minor_version)
1021  *      loads and validates a superblock on dev.
1022  *      if refdev != NULL, compare superblocks on both devices
1023  *    Return:
1024  *      0 - dev has a superblock that is compatible with refdev
1025  *      1 - dev has a superblock that is compatible and newer than refdev
1026  *          so dev should be used as the refdev in future
1027  *     -EINVAL superblock incompatible or invalid
1028  *     -othererror e.g. -EIO
1029  *
1030  *   int validate_super(struct mddev *mddev, struct md_rdev *dev)
1031  *      Verify that dev is acceptable into mddev.
1032  *       The first time, mddev->raid_disks will be 0, and data from
1033  *       dev should be merged in.  Subsequent calls check that dev
1034  *       is new enough.  Return 0 or -EINVAL
1035  *
1036  *   void sync_super(struct mddev *mddev, struct md_rdev *dev)
1037  *     Update the superblock for rdev with data in mddev
1038  *     This does not write to disc.
1039  *
1040  */
1041 
1042 struct super_type  {
1043 	char		    *name;
1044 	struct module	    *owner;
1045 	int		    (*load_super)(struct md_rdev *rdev,
1046 					  struct md_rdev *refdev,
1047 					  int minor_version);
1048 	int		    (*validate_super)(struct mddev *mddev,
1049 					      struct md_rdev *rdev);
1050 	void		    (*sync_super)(struct mddev *mddev,
1051 					  struct md_rdev *rdev);
1052 	unsigned long long  (*rdev_size_change)(struct md_rdev *rdev,
1053 						sector_t num_sectors);
1054 	int		    (*allow_new_offset)(struct md_rdev *rdev,
1055 						unsigned long long new_offset);
1056 };
1057 
1058 /*
1059  * Check that the given mddev has no bitmap.
1060  *
1061  * This function is called from the run method of all personalities that do not
1062  * support bitmaps. It prints an error message and returns non-zero if mddev
1063  * has a bitmap. Otherwise, it returns 0.
1064  *
1065  */
1066 int md_check_no_bitmap(struct mddev *mddev)
1067 {
1068 	if (!mddev->bitmap_info.file && !mddev->bitmap_info.offset)
1069 		return 0;
1070 	printk(KERN_ERR "%s: bitmaps are not supported for %s\n",
1071 		mdname(mddev), mddev->pers->name);
1072 	return 1;
1073 }
1074 EXPORT_SYMBOL(md_check_no_bitmap);
1075 
1076 /*
1077  * load_super for 0.90.0
1078  */
1079 static int super_90_load(struct md_rdev *rdev, struct md_rdev *refdev, int minor_version)
1080 {
1081 	char b[BDEVNAME_SIZE], b2[BDEVNAME_SIZE];
1082 	mdp_super_t *sb;
1083 	int ret;
1084 
1085 	/*
1086 	 * Calculate the position of the superblock (512byte sectors),
1087 	 * it's at the end of the disk.
1088 	 *
1089 	 * It also happens to be a multiple of 4Kb.
1090 	 */
1091 	rdev->sb_start = calc_dev_sboffset(rdev);
1092 
1093 	ret = read_disk_sb(rdev, MD_SB_BYTES);
1094 	if (ret) return ret;
1095 
1096 	ret = -EINVAL;
1097 
1098 	bdevname(rdev->bdev, b);
1099 	sb = page_address(rdev->sb_page);
1100 
1101 	if (sb->md_magic != MD_SB_MAGIC) {
1102 		printk(KERN_ERR "md: invalid raid superblock magic on %s\n",
1103 		       b);
1104 		goto abort;
1105 	}
1106 
1107 	if (sb->major_version != 0 ||
1108 	    sb->minor_version < 90 ||
1109 	    sb->minor_version > 91) {
1110 		printk(KERN_WARNING "Bad version number %d.%d on %s\n",
1111 			sb->major_version, sb->minor_version,
1112 			b);
1113 		goto abort;
1114 	}
1115 
1116 	if (sb->raid_disks <= 0)
1117 		goto abort;
1118 
1119 	if (md_csum_fold(calc_sb_csum(sb)) != md_csum_fold(sb->sb_csum)) {
1120 		printk(KERN_WARNING "md: invalid superblock checksum on %s\n",
1121 			b);
1122 		goto abort;
1123 	}
1124 
1125 	rdev->preferred_minor = sb->md_minor;
1126 	rdev->data_offset = 0;
1127 	rdev->new_data_offset = 0;
1128 	rdev->sb_size = MD_SB_BYTES;
1129 	rdev->badblocks.shift = -1;
1130 
1131 	if (sb->level == LEVEL_MULTIPATH)
1132 		rdev->desc_nr = -1;
1133 	else
1134 		rdev->desc_nr = sb->this_disk.number;
1135 
1136 	if (!refdev) {
1137 		ret = 1;
1138 	} else {
1139 		__u64 ev1, ev2;
1140 		mdp_super_t *refsb = page_address(refdev->sb_page);
1141 		if (!uuid_equal(refsb, sb)) {
1142 			printk(KERN_WARNING "md: %s has different UUID to %s\n",
1143 				b, bdevname(refdev->bdev,b2));
1144 			goto abort;
1145 		}
1146 		if (!sb_equal(refsb, sb)) {
1147 			printk(KERN_WARNING "md: %s has same UUID"
1148 			       " but different superblock to %s\n",
1149 			       b, bdevname(refdev->bdev, b2));
1150 			goto abort;
1151 		}
1152 		ev1 = md_event(sb);
1153 		ev2 = md_event(refsb);
1154 		if (ev1 > ev2)
1155 			ret = 1;
1156 		else
1157 			ret = 0;
1158 	}
1159 	rdev->sectors = rdev->sb_start;
1160 	/* Limit to 4TB as metadata cannot record more than that */
1161 	if (rdev->sectors >= (2ULL << 32))
1162 		rdev->sectors = (2ULL << 32) - 2;
1163 
1164 	if (rdev->sectors < ((sector_t)sb->size) * 2 && sb->level >= 1)
1165 		/* "this cannot possibly happen" ... */
1166 		ret = -EINVAL;
1167 
1168  abort:
1169 	return ret;
1170 }
1171 
1172 /*
1173  * validate_super for 0.90.0
1174  */
1175 static int super_90_validate(struct mddev *mddev, struct md_rdev *rdev)
1176 {
1177 	mdp_disk_t *desc;
1178 	mdp_super_t *sb = page_address(rdev->sb_page);
1179 	__u64 ev1 = md_event(sb);
1180 
1181 	rdev->raid_disk = -1;
1182 	clear_bit(Faulty, &rdev->flags);
1183 	clear_bit(In_sync, &rdev->flags);
1184 	clear_bit(WriteMostly, &rdev->flags);
1185 
1186 	if (mddev->raid_disks == 0) {
1187 		mddev->major_version = 0;
1188 		mddev->minor_version = sb->minor_version;
1189 		mddev->patch_version = sb->patch_version;
1190 		mddev->external = 0;
1191 		mddev->chunk_sectors = sb->chunk_size >> 9;
1192 		mddev->ctime = sb->ctime;
1193 		mddev->utime = sb->utime;
1194 		mddev->level = sb->level;
1195 		mddev->clevel[0] = 0;
1196 		mddev->layout = sb->layout;
1197 		mddev->raid_disks = sb->raid_disks;
1198 		mddev->dev_sectors = ((sector_t)sb->size) * 2;
1199 		mddev->events = ev1;
1200 		mddev->bitmap_info.offset = 0;
1201 		mddev->bitmap_info.space = 0;
1202 		/* bitmap can use 60 K after the 4K superblocks */
1203 		mddev->bitmap_info.default_offset = MD_SB_BYTES >> 9;
1204 		mddev->bitmap_info.default_space = 64*2 - (MD_SB_BYTES >> 9);
1205 		mddev->reshape_backwards = 0;
1206 
1207 		if (mddev->minor_version >= 91) {
1208 			mddev->reshape_position = sb->reshape_position;
1209 			mddev->delta_disks = sb->delta_disks;
1210 			mddev->new_level = sb->new_level;
1211 			mddev->new_layout = sb->new_layout;
1212 			mddev->new_chunk_sectors = sb->new_chunk >> 9;
1213 			if (mddev->delta_disks < 0)
1214 				mddev->reshape_backwards = 1;
1215 		} else {
1216 			mddev->reshape_position = MaxSector;
1217 			mddev->delta_disks = 0;
1218 			mddev->new_level = mddev->level;
1219 			mddev->new_layout = mddev->layout;
1220 			mddev->new_chunk_sectors = mddev->chunk_sectors;
1221 		}
1222 
1223 		if (sb->state & (1<<MD_SB_CLEAN))
1224 			mddev->recovery_cp = MaxSector;
1225 		else {
1226 			if (sb->events_hi == sb->cp_events_hi &&
1227 				sb->events_lo == sb->cp_events_lo) {
1228 				mddev->recovery_cp = sb->recovery_cp;
1229 			} else
1230 				mddev->recovery_cp = 0;
1231 		}
1232 
1233 		memcpy(mddev->uuid+0, &sb->set_uuid0, 4);
1234 		memcpy(mddev->uuid+4, &sb->set_uuid1, 4);
1235 		memcpy(mddev->uuid+8, &sb->set_uuid2, 4);
1236 		memcpy(mddev->uuid+12,&sb->set_uuid3, 4);
1237 
1238 		mddev->max_disks = MD_SB_DISKS;
1239 
1240 		if (sb->state & (1<<MD_SB_BITMAP_PRESENT) &&
1241 		    mddev->bitmap_info.file == NULL) {
1242 			mddev->bitmap_info.offset =
1243 				mddev->bitmap_info.default_offset;
1244 			mddev->bitmap_info.space =
1245 				mddev->bitmap_info.space;
1246 		}
1247 
1248 	} else if (mddev->pers == NULL) {
1249 		/* Insist on good event counter while assembling, except
1250 		 * for spares (which don't need an event count) */
1251 		++ev1;
1252 		if (sb->disks[rdev->desc_nr].state & (
1253 			    (1<<MD_DISK_SYNC) | (1 << MD_DISK_ACTIVE)))
1254 			if (ev1 < mddev->events)
1255 				return -EINVAL;
1256 	} else if (mddev->bitmap) {
1257 		/* if adding to array with a bitmap, then we can accept an
1258 		 * older device ... but not too old.
1259 		 */
1260 		if (ev1 < mddev->bitmap->events_cleared)
1261 			return 0;
1262 	} else {
1263 		if (ev1 < mddev->events)
1264 			/* just a hot-add of a new device, leave raid_disk at -1 */
1265 			return 0;
1266 	}
1267 
1268 	if (mddev->level != LEVEL_MULTIPATH) {
1269 		desc = sb->disks + rdev->desc_nr;
1270 
1271 		if (desc->state & (1<<MD_DISK_FAULTY))
1272 			set_bit(Faulty, &rdev->flags);
1273 		else if (desc->state & (1<<MD_DISK_SYNC) /* &&
1274 			    desc->raid_disk < mddev->raid_disks */) {
1275 			set_bit(In_sync, &rdev->flags);
1276 			rdev->raid_disk = desc->raid_disk;
1277 		} else if (desc->state & (1<<MD_DISK_ACTIVE)) {
1278 			/* active but not in sync implies recovery up to
1279 			 * reshape position.  We don't know exactly where
1280 			 * that is, so set to zero for now */
1281 			if (mddev->minor_version >= 91) {
1282 				rdev->recovery_offset = 0;
1283 				rdev->raid_disk = desc->raid_disk;
1284 			}
1285 		}
1286 		if (desc->state & (1<<MD_DISK_WRITEMOSTLY))
1287 			set_bit(WriteMostly, &rdev->flags);
1288 	} else /* MULTIPATH are always insync */
1289 		set_bit(In_sync, &rdev->flags);
1290 	return 0;
1291 }
1292 
1293 /*
1294  * sync_super for 0.90.0
1295  */
1296 static void super_90_sync(struct mddev *mddev, struct md_rdev *rdev)
1297 {
1298 	mdp_super_t *sb;
1299 	struct md_rdev *rdev2;
1300 	int next_spare = mddev->raid_disks;
1301 
1302 
1303 	/* make rdev->sb match mddev data..
1304 	 *
1305 	 * 1/ zero out disks
1306 	 * 2/ Add info for each disk, keeping track of highest desc_nr (next_spare);
1307 	 * 3/ any empty disks < next_spare become removed
1308 	 *
1309 	 * disks[0] gets initialised to REMOVED because
1310 	 * we cannot be sure from other fields if it has
1311 	 * been initialised or not.
1312 	 */
1313 	int i;
1314 	int active=0, working=0,failed=0,spare=0,nr_disks=0;
1315 
1316 	rdev->sb_size = MD_SB_BYTES;
1317 
1318 	sb = page_address(rdev->sb_page);
1319 
1320 	memset(sb, 0, sizeof(*sb));
1321 
1322 	sb->md_magic = MD_SB_MAGIC;
1323 	sb->major_version = mddev->major_version;
1324 	sb->patch_version = mddev->patch_version;
1325 	sb->gvalid_words  = 0; /* ignored */
1326 	memcpy(&sb->set_uuid0, mddev->uuid+0, 4);
1327 	memcpy(&sb->set_uuid1, mddev->uuid+4, 4);
1328 	memcpy(&sb->set_uuid2, mddev->uuid+8, 4);
1329 	memcpy(&sb->set_uuid3, mddev->uuid+12,4);
1330 
1331 	sb->ctime = mddev->ctime;
1332 	sb->level = mddev->level;
1333 	sb->size = mddev->dev_sectors / 2;
1334 	sb->raid_disks = mddev->raid_disks;
1335 	sb->md_minor = mddev->md_minor;
1336 	sb->not_persistent = 0;
1337 	sb->utime = mddev->utime;
1338 	sb->state = 0;
1339 	sb->events_hi = (mddev->events>>32);
1340 	sb->events_lo = (u32)mddev->events;
1341 
1342 	if (mddev->reshape_position == MaxSector)
1343 		sb->minor_version = 90;
1344 	else {
1345 		sb->minor_version = 91;
1346 		sb->reshape_position = mddev->reshape_position;
1347 		sb->new_level = mddev->new_level;
1348 		sb->delta_disks = mddev->delta_disks;
1349 		sb->new_layout = mddev->new_layout;
1350 		sb->new_chunk = mddev->new_chunk_sectors << 9;
1351 	}
1352 	mddev->minor_version = sb->minor_version;
1353 	if (mddev->in_sync)
1354 	{
1355 		sb->recovery_cp = mddev->recovery_cp;
1356 		sb->cp_events_hi = (mddev->events>>32);
1357 		sb->cp_events_lo = (u32)mddev->events;
1358 		if (mddev->recovery_cp == MaxSector)
1359 			sb->state = (1<< MD_SB_CLEAN);
1360 	} else
1361 		sb->recovery_cp = 0;
1362 
1363 	sb->layout = mddev->layout;
1364 	sb->chunk_size = mddev->chunk_sectors << 9;
1365 
1366 	if (mddev->bitmap && mddev->bitmap_info.file == NULL)
1367 		sb->state |= (1<<MD_SB_BITMAP_PRESENT);
1368 
1369 	sb->disks[0].state = (1<<MD_DISK_REMOVED);
1370 	rdev_for_each(rdev2, mddev) {
1371 		mdp_disk_t *d;
1372 		int desc_nr;
1373 		int is_active = test_bit(In_sync, &rdev2->flags);
1374 
1375 		if (rdev2->raid_disk >= 0 &&
1376 		    sb->minor_version >= 91)
1377 			/* we have nowhere to store the recovery_offset,
1378 			 * but if it is not below the reshape_position,
1379 			 * we can piggy-back on that.
1380 			 */
1381 			is_active = 1;
1382 		if (rdev2->raid_disk < 0 ||
1383 		    test_bit(Faulty, &rdev2->flags))
1384 			is_active = 0;
1385 		if (is_active)
1386 			desc_nr = rdev2->raid_disk;
1387 		else
1388 			desc_nr = next_spare++;
1389 		rdev2->desc_nr = desc_nr;
1390 		d = &sb->disks[rdev2->desc_nr];
1391 		nr_disks++;
1392 		d->number = rdev2->desc_nr;
1393 		d->major = MAJOR(rdev2->bdev->bd_dev);
1394 		d->minor = MINOR(rdev2->bdev->bd_dev);
1395 		if (is_active)
1396 			d->raid_disk = rdev2->raid_disk;
1397 		else
1398 			d->raid_disk = rdev2->desc_nr; /* compatibility */
1399 		if (test_bit(Faulty, &rdev2->flags))
1400 			d->state = (1<<MD_DISK_FAULTY);
1401 		else if (is_active) {
1402 			d->state = (1<<MD_DISK_ACTIVE);
1403 			if (test_bit(In_sync, &rdev2->flags))
1404 				d->state |= (1<<MD_DISK_SYNC);
1405 			active++;
1406 			working++;
1407 		} else {
1408 			d->state = 0;
1409 			spare++;
1410 			working++;
1411 		}
1412 		if (test_bit(WriteMostly, &rdev2->flags))
1413 			d->state |= (1<<MD_DISK_WRITEMOSTLY);
1414 	}
1415 	/* now set the "removed" and "faulty" bits on any missing devices */
1416 	for (i=0 ; i < mddev->raid_disks ; i++) {
1417 		mdp_disk_t *d = &sb->disks[i];
1418 		if (d->state == 0 && d->number == 0) {
1419 			d->number = i;
1420 			d->raid_disk = i;
1421 			d->state = (1<<MD_DISK_REMOVED);
1422 			d->state |= (1<<MD_DISK_FAULTY);
1423 			failed++;
1424 		}
1425 	}
1426 	sb->nr_disks = nr_disks;
1427 	sb->active_disks = active;
1428 	sb->working_disks = working;
1429 	sb->failed_disks = failed;
1430 	sb->spare_disks = spare;
1431 
1432 	sb->this_disk = sb->disks[rdev->desc_nr];
1433 	sb->sb_csum = calc_sb_csum(sb);
1434 }
1435 
1436 /*
1437  * rdev_size_change for 0.90.0
1438  */
1439 static unsigned long long
1440 super_90_rdev_size_change(struct md_rdev *rdev, sector_t num_sectors)
1441 {
1442 	if (num_sectors && num_sectors < rdev->mddev->dev_sectors)
1443 		return 0; /* component must fit device */
1444 	if (rdev->mddev->bitmap_info.offset)
1445 		return 0; /* can't move bitmap */
1446 	rdev->sb_start = calc_dev_sboffset(rdev);
1447 	if (!num_sectors || num_sectors > rdev->sb_start)
1448 		num_sectors = rdev->sb_start;
1449 	/* Limit to 4TB as metadata cannot record more than that.
1450 	 * 4TB == 2^32 KB, or 2*2^32 sectors.
1451 	 */
1452 	if (num_sectors >= (2ULL << 32))
1453 		num_sectors = (2ULL << 32) - 2;
1454 	md_super_write(rdev->mddev, rdev, rdev->sb_start, rdev->sb_size,
1455 		       rdev->sb_page);
1456 	md_super_wait(rdev->mddev);
1457 	return num_sectors;
1458 }
1459 
1460 static int
1461 super_90_allow_new_offset(struct md_rdev *rdev, unsigned long long new_offset)
1462 {
1463 	/* non-zero offset changes not possible with v0.90 */
1464 	return new_offset == 0;
1465 }
1466 
1467 /*
1468  * version 1 superblock
1469  */
1470 
1471 static __le32 calc_sb_1_csum(struct mdp_superblock_1 * sb)
1472 {
1473 	__le32 disk_csum;
1474 	u32 csum;
1475 	unsigned long long newcsum;
1476 	int size = 256 + le32_to_cpu(sb->max_dev)*2;
1477 	__le32 *isuper = (__le32*)sb;
1478 	int i;
1479 
1480 	disk_csum = sb->sb_csum;
1481 	sb->sb_csum = 0;
1482 	newcsum = 0;
1483 	for (i=0; size>=4; size -= 4 )
1484 		newcsum += le32_to_cpu(*isuper++);
1485 
1486 	if (size == 2)
1487 		newcsum += le16_to_cpu(*(__le16*) isuper);
1488 
1489 	csum = (newcsum & 0xffffffff) + (newcsum >> 32);
1490 	sb->sb_csum = disk_csum;
1491 	return cpu_to_le32(csum);
1492 }
1493 
1494 static int md_set_badblocks(struct badblocks *bb, sector_t s, int sectors,
1495 			    int acknowledged);
1496 static int super_1_load(struct md_rdev *rdev, struct md_rdev *refdev, int minor_version)
1497 {
1498 	struct mdp_superblock_1 *sb;
1499 	int ret;
1500 	sector_t sb_start;
1501 	sector_t sectors;
1502 	char b[BDEVNAME_SIZE], b2[BDEVNAME_SIZE];
1503 	int bmask;
1504 
1505 	/*
1506 	 * Calculate the position of the superblock in 512byte sectors.
1507 	 * It is always aligned to a 4K boundary and
1508 	 * depeding on minor_version, it can be:
1509 	 * 0: At least 8K, but less than 12K, from end of device
1510 	 * 1: At start of device
1511 	 * 2: 4K from start of device.
1512 	 */
1513 	switch(minor_version) {
1514 	case 0:
1515 		sb_start = i_size_read(rdev->bdev->bd_inode) >> 9;
1516 		sb_start -= 8*2;
1517 		sb_start &= ~(sector_t)(4*2-1);
1518 		break;
1519 	case 1:
1520 		sb_start = 0;
1521 		break;
1522 	case 2:
1523 		sb_start = 8;
1524 		break;
1525 	default:
1526 		return -EINVAL;
1527 	}
1528 	rdev->sb_start = sb_start;
1529 
1530 	/* superblock is rarely larger than 1K, but it can be larger,
1531 	 * and it is safe to read 4k, so we do that
1532 	 */
1533 	ret = read_disk_sb(rdev, 4096);
1534 	if (ret) return ret;
1535 
1536 
1537 	sb = page_address(rdev->sb_page);
1538 
1539 	if (sb->magic != cpu_to_le32(MD_SB_MAGIC) ||
1540 	    sb->major_version != cpu_to_le32(1) ||
1541 	    le32_to_cpu(sb->max_dev) > (4096-256)/2 ||
1542 	    le64_to_cpu(sb->super_offset) != rdev->sb_start ||
1543 	    (le32_to_cpu(sb->feature_map) & ~MD_FEATURE_ALL) != 0)
1544 		return -EINVAL;
1545 
1546 	if (calc_sb_1_csum(sb) != sb->sb_csum) {
1547 		printk("md: invalid superblock checksum on %s\n",
1548 			bdevname(rdev->bdev,b));
1549 		return -EINVAL;
1550 	}
1551 	if (le64_to_cpu(sb->data_size) < 10) {
1552 		printk("md: data_size too small on %s\n",
1553 		       bdevname(rdev->bdev,b));
1554 		return -EINVAL;
1555 	}
1556 	if (sb->pad0 ||
1557 	    sb->pad3[0] ||
1558 	    memcmp(sb->pad3, sb->pad3+1, sizeof(sb->pad3) - sizeof(sb->pad3[1])))
1559 		/* Some padding is non-zero, might be a new feature */
1560 		return -EINVAL;
1561 
1562 	rdev->preferred_minor = 0xffff;
1563 	rdev->data_offset = le64_to_cpu(sb->data_offset);
1564 	rdev->new_data_offset = rdev->data_offset;
1565 	if ((le32_to_cpu(sb->feature_map) & MD_FEATURE_RESHAPE_ACTIVE) &&
1566 	    (le32_to_cpu(sb->feature_map) & MD_FEATURE_NEW_OFFSET))
1567 		rdev->new_data_offset += (s32)le32_to_cpu(sb->new_offset);
1568 	atomic_set(&rdev->corrected_errors, le32_to_cpu(sb->cnt_corrected_read));
1569 
1570 	rdev->sb_size = le32_to_cpu(sb->max_dev) * 2 + 256;
1571 	bmask = queue_logical_block_size(rdev->bdev->bd_disk->queue)-1;
1572 	if (rdev->sb_size & bmask)
1573 		rdev->sb_size = (rdev->sb_size | bmask) + 1;
1574 
1575 	if (minor_version
1576 	    && rdev->data_offset < sb_start + (rdev->sb_size/512))
1577 		return -EINVAL;
1578 	if (minor_version
1579 	    && rdev->new_data_offset < sb_start + (rdev->sb_size/512))
1580 		return -EINVAL;
1581 
1582 	if (sb->level == cpu_to_le32(LEVEL_MULTIPATH))
1583 		rdev->desc_nr = -1;
1584 	else
1585 		rdev->desc_nr = le32_to_cpu(sb->dev_number);
1586 
1587 	if (!rdev->bb_page) {
1588 		rdev->bb_page = alloc_page(GFP_KERNEL);
1589 		if (!rdev->bb_page)
1590 			return -ENOMEM;
1591 	}
1592 	if ((le32_to_cpu(sb->feature_map) & MD_FEATURE_BAD_BLOCKS) &&
1593 	    rdev->badblocks.count == 0) {
1594 		/* need to load the bad block list.
1595 		 * Currently we limit it to one page.
1596 		 */
1597 		s32 offset;
1598 		sector_t bb_sector;
1599 		u64 *bbp;
1600 		int i;
1601 		int sectors = le16_to_cpu(sb->bblog_size);
1602 		if (sectors > (PAGE_SIZE / 512))
1603 			return -EINVAL;
1604 		offset = le32_to_cpu(sb->bblog_offset);
1605 		if (offset == 0)
1606 			return -EINVAL;
1607 		bb_sector = (long long)offset;
1608 		if (!sync_page_io(rdev, bb_sector, sectors << 9,
1609 				  rdev->bb_page, READ, true))
1610 			return -EIO;
1611 		bbp = (u64 *)page_address(rdev->bb_page);
1612 		rdev->badblocks.shift = sb->bblog_shift;
1613 		for (i = 0 ; i < (sectors << (9-3)) ; i++, bbp++) {
1614 			u64 bb = le64_to_cpu(*bbp);
1615 			int count = bb & (0x3ff);
1616 			u64 sector = bb >> 10;
1617 			sector <<= sb->bblog_shift;
1618 			count <<= sb->bblog_shift;
1619 			if (bb + 1 == 0)
1620 				break;
1621 			if (md_set_badblocks(&rdev->badblocks,
1622 					     sector, count, 1) == 0)
1623 				return -EINVAL;
1624 		}
1625 	} else if (sb->bblog_offset == 0)
1626 		rdev->badblocks.shift = -1;
1627 
1628 	if (!refdev) {
1629 		ret = 1;
1630 	} else {
1631 		__u64 ev1, ev2;
1632 		struct mdp_superblock_1 *refsb = page_address(refdev->sb_page);
1633 
1634 		if (memcmp(sb->set_uuid, refsb->set_uuid, 16) != 0 ||
1635 		    sb->level != refsb->level ||
1636 		    sb->layout != refsb->layout ||
1637 		    sb->chunksize != refsb->chunksize) {
1638 			printk(KERN_WARNING "md: %s has strangely different"
1639 				" superblock to %s\n",
1640 				bdevname(rdev->bdev,b),
1641 				bdevname(refdev->bdev,b2));
1642 			return -EINVAL;
1643 		}
1644 		ev1 = le64_to_cpu(sb->events);
1645 		ev2 = le64_to_cpu(refsb->events);
1646 
1647 		if (ev1 > ev2)
1648 			ret = 1;
1649 		else
1650 			ret = 0;
1651 	}
1652 	if (minor_version) {
1653 		sectors = (i_size_read(rdev->bdev->bd_inode) >> 9);
1654 		sectors -= rdev->data_offset;
1655 	} else
1656 		sectors = rdev->sb_start;
1657 	if (sectors < le64_to_cpu(sb->data_size))
1658 		return -EINVAL;
1659 	rdev->sectors = le64_to_cpu(sb->data_size);
1660 	return ret;
1661 }
1662 
1663 static int super_1_validate(struct mddev *mddev, struct md_rdev *rdev)
1664 {
1665 	struct mdp_superblock_1 *sb = page_address(rdev->sb_page);
1666 	__u64 ev1 = le64_to_cpu(sb->events);
1667 
1668 	rdev->raid_disk = -1;
1669 	clear_bit(Faulty, &rdev->flags);
1670 	clear_bit(In_sync, &rdev->flags);
1671 	clear_bit(WriteMostly, &rdev->flags);
1672 
1673 	if (mddev->raid_disks == 0) {
1674 		mddev->major_version = 1;
1675 		mddev->patch_version = 0;
1676 		mddev->external = 0;
1677 		mddev->chunk_sectors = le32_to_cpu(sb->chunksize);
1678 		mddev->ctime = le64_to_cpu(sb->ctime) & ((1ULL << 32)-1);
1679 		mddev->utime = le64_to_cpu(sb->utime) & ((1ULL << 32)-1);
1680 		mddev->level = le32_to_cpu(sb->level);
1681 		mddev->clevel[0] = 0;
1682 		mddev->layout = le32_to_cpu(sb->layout);
1683 		mddev->raid_disks = le32_to_cpu(sb->raid_disks);
1684 		mddev->dev_sectors = le64_to_cpu(sb->size);
1685 		mddev->events = ev1;
1686 		mddev->bitmap_info.offset = 0;
1687 		mddev->bitmap_info.space = 0;
1688 		/* Default location for bitmap is 1K after superblock
1689 		 * using 3K - total of 4K
1690 		 */
1691 		mddev->bitmap_info.default_offset = 1024 >> 9;
1692 		mddev->bitmap_info.default_space = (4096-1024) >> 9;
1693 		mddev->reshape_backwards = 0;
1694 
1695 		mddev->recovery_cp = le64_to_cpu(sb->resync_offset);
1696 		memcpy(mddev->uuid, sb->set_uuid, 16);
1697 
1698 		mddev->max_disks =  (4096-256)/2;
1699 
1700 		if ((le32_to_cpu(sb->feature_map) & MD_FEATURE_BITMAP_OFFSET) &&
1701 		    mddev->bitmap_info.file == NULL) {
1702 			mddev->bitmap_info.offset =
1703 				(__s32)le32_to_cpu(sb->bitmap_offset);
1704 			/* Metadata doesn't record how much space is available.
1705 			 * For 1.0, we assume we can use up to the superblock
1706 			 * if before, else to 4K beyond superblock.
1707 			 * For others, assume no change is possible.
1708 			 */
1709 			if (mddev->minor_version > 0)
1710 				mddev->bitmap_info.space = 0;
1711 			else if (mddev->bitmap_info.offset > 0)
1712 				mddev->bitmap_info.space =
1713 					8 - mddev->bitmap_info.offset;
1714 			else
1715 				mddev->bitmap_info.space =
1716 					-mddev->bitmap_info.offset;
1717 		}
1718 
1719 		if ((le32_to_cpu(sb->feature_map) & MD_FEATURE_RESHAPE_ACTIVE)) {
1720 			mddev->reshape_position = le64_to_cpu(sb->reshape_position);
1721 			mddev->delta_disks = le32_to_cpu(sb->delta_disks);
1722 			mddev->new_level = le32_to_cpu(sb->new_level);
1723 			mddev->new_layout = le32_to_cpu(sb->new_layout);
1724 			mddev->new_chunk_sectors = le32_to_cpu(sb->new_chunk);
1725 			if (mddev->delta_disks < 0 ||
1726 			    (mddev->delta_disks == 0 &&
1727 			     (le32_to_cpu(sb->feature_map)
1728 			      & MD_FEATURE_RESHAPE_BACKWARDS)))
1729 				mddev->reshape_backwards = 1;
1730 		} else {
1731 			mddev->reshape_position = MaxSector;
1732 			mddev->delta_disks = 0;
1733 			mddev->new_level = mddev->level;
1734 			mddev->new_layout = mddev->layout;
1735 			mddev->new_chunk_sectors = mddev->chunk_sectors;
1736 		}
1737 
1738 	} else if (mddev->pers == NULL) {
1739 		/* Insist of good event counter while assembling, except for
1740 		 * spares (which don't need an event count) */
1741 		++ev1;
1742 		if (rdev->desc_nr >= 0 &&
1743 		    rdev->desc_nr < le32_to_cpu(sb->max_dev) &&
1744 		    le16_to_cpu(sb->dev_roles[rdev->desc_nr]) < 0xfffe)
1745 			if (ev1 < mddev->events)
1746 				return -EINVAL;
1747 	} else if (mddev->bitmap) {
1748 		/* If adding to array with a bitmap, then we can accept an
1749 		 * older device, but not too old.
1750 		 */
1751 		if (ev1 < mddev->bitmap->events_cleared)
1752 			return 0;
1753 	} else {
1754 		if (ev1 < mddev->events)
1755 			/* just a hot-add of a new device, leave raid_disk at -1 */
1756 			return 0;
1757 	}
1758 	if (mddev->level != LEVEL_MULTIPATH) {
1759 		int role;
1760 		if (rdev->desc_nr < 0 ||
1761 		    rdev->desc_nr >= le32_to_cpu(sb->max_dev)) {
1762 			role = 0xffff;
1763 			rdev->desc_nr = -1;
1764 		} else
1765 			role = le16_to_cpu(sb->dev_roles[rdev->desc_nr]);
1766 		switch(role) {
1767 		case 0xffff: /* spare */
1768 			break;
1769 		case 0xfffe: /* faulty */
1770 			set_bit(Faulty, &rdev->flags);
1771 			break;
1772 		default:
1773 			if ((le32_to_cpu(sb->feature_map) &
1774 			     MD_FEATURE_RECOVERY_OFFSET))
1775 				rdev->recovery_offset = le64_to_cpu(sb->recovery_offset);
1776 			else
1777 				set_bit(In_sync, &rdev->flags);
1778 			rdev->raid_disk = role;
1779 			break;
1780 		}
1781 		if (sb->devflags & WriteMostly1)
1782 			set_bit(WriteMostly, &rdev->flags);
1783 		if (le32_to_cpu(sb->feature_map) & MD_FEATURE_REPLACEMENT)
1784 			set_bit(Replacement, &rdev->flags);
1785 	} else /* MULTIPATH are always insync */
1786 		set_bit(In_sync, &rdev->flags);
1787 
1788 	return 0;
1789 }
1790 
1791 static void super_1_sync(struct mddev *mddev, struct md_rdev *rdev)
1792 {
1793 	struct mdp_superblock_1 *sb;
1794 	struct md_rdev *rdev2;
1795 	int max_dev, i;
1796 	/* make rdev->sb match mddev and rdev data. */
1797 
1798 	sb = page_address(rdev->sb_page);
1799 
1800 	sb->feature_map = 0;
1801 	sb->pad0 = 0;
1802 	sb->recovery_offset = cpu_to_le64(0);
1803 	memset(sb->pad3, 0, sizeof(sb->pad3));
1804 
1805 	sb->utime = cpu_to_le64((__u64)mddev->utime);
1806 	sb->events = cpu_to_le64(mddev->events);
1807 	if (mddev->in_sync)
1808 		sb->resync_offset = cpu_to_le64(mddev->recovery_cp);
1809 	else
1810 		sb->resync_offset = cpu_to_le64(0);
1811 
1812 	sb->cnt_corrected_read = cpu_to_le32(atomic_read(&rdev->corrected_errors));
1813 
1814 	sb->raid_disks = cpu_to_le32(mddev->raid_disks);
1815 	sb->size = cpu_to_le64(mddev->dev_sectors);
1816 	sb->chunksize = cpu_to_le32(mddev->chunk_sectors);
1817 	sb->level = cpu_to_le32(mddev->level);
1818 	sb->layout = cpu_to_le32(mddev->layout);
1819 
1820 	if (test_bit(WriteMostly, &rdev->flags))
1821 		sb->devflags |= WriteMostly1;
1822 	else
1823 		sb->devflags &= ~WriteMostly1;
1824 	sb->data_offset = cpu_to_le64(rdev->data_offset);
1825 	sb->data_size = cpu_to_le64(rdev->sectors);
1826 
1827 	if (mddev->bitmap && mddev->bitmap_info.file == NULL) {
1828 		sb->bitmap_offset = cpu_to_le32((__u32)mddev->bitmap_info.offset);
1829 		sb->feature_map = cpu_to_le32(MD_FEATURE_BITMAP_OFFSET);
1830 	}
1831 
1832 	if (rdev->raid_disk >= 0 &&
1833 	    !test_bit(In_sync, &rdev->flags)) {
1834 		sb->feature_map |=
1835 			cpu_to_le32(MD_FEATURE_RECOVERY_OFFSET);
1836 		sb->recovery_offset =
1837 			cpu_to_le64(rdev->recovery_offset);
1838 	}
1839 	if (test_bit(Replacement, &rdev->flags))
1840 		sb->feature_map |=
1841 			cpu_to_le32(MD_FEATURE_REPLACEMENT);
1842 
1843 	if (mddev->reshape_position != MaxSector) {
1844 		sb->feature_map |= cpu_to_le32(MD_FEATURE_RESHAPE_ACTIVE);
1845 		sb->reshape_position = cpu_to_le64(mddev->reshape_position);
1846 		sb->new_layout = cpu_to_le32(mddev->new_layout);
1847 		sb->delta_disks = cpu_to_le32(mddev->delta_disks);
1848 		sb->new_level = cpu_to_le32(mddev->new_level);
1849 		sb->new_chunk = cpu_to_le32(mddev->new_chunk_sectors);
1850 		if (mddev->delta_disks == 0 &&
1851 		    mddev->reshape_backwards)
1852 			sb->feature_map
1853 				|= cpu_to_le32(MD_FEATURE_RESHAPE_BACKWARDS);
1854 		if (rdev->new_data_offset != rdev->data_offset) {
1855 			sb->feature_map
1856 				|= cpu_to_le32(MD_FEATURE_NEW_OFFSET);
1857 			sb->new_offset = cpu_to_le32((__u32)(rdev->new_data_offset
1858 							     - rdev->data_offset));
1859 		}
1860 	}
1861 
1862 	if (rdev->badblocks.count == 0)
1863 		/* Nothing to do for bad blocks*/ ;
1864 	else if (sb->bblog_offset == 0)
1865 		/* Cannot record bad blocks on this device */
1866 		md_error(mddev, rdev);
1867 	else {
1868 		struct badblocks *bb = &rdev->badblocks;
1869 		u64 *bbp = (u64 *)page_address(rdev->bb_page);
1870 		u64 *p = bb->page;
1871 		sb->feature_map |= cpu_to_le32(MD_FEATURE_BAD_BLOCKS);
1872 		if (bb->changed) {
1873 			unsigned seq;
1874 
1875 retry:
1876 			seq = read_seqbegin(&bb->lock);
1877 
1878 			memset(bbp, 0xff, PAGE_SIZE);
1879 
1880 			for (i = 0 ; i < bb->count ; i++) {
1881 				u64 internal_bb = *p++;
1882 				u64 store_bb = ((BB_OFFSET(internal_bb) << 10)
1883 						| BB_LEN(internal_bb));
1884 				*bbp++ = cpu_to_le64(store_bb);
1885 			}
1886 			bb->changed = 0;
1887 			if (read_seqretry(&bb->lock, seq))
1888 				goto retry;
1889 
1890 			bb->sector = (rdev->sb_start +
1891 				      (int)le32_to_cpu(sb->bblog_offset));
1892 			bb->size = le16_to_cpu(sb->bblog_size);
1893 		}
1894 	}
1895 
1896 	max_dev = 0;
1897 	rdev_for_each(rdev2, mddev)
1898 		if (rdev2->desc_nr+1 > max_dev)
1899 			max_dev = rdev2->desc_nr+1;
1900 
1901 	if (max_dev > le32_to_cpu(sb->max_dev)) {
1902 		int bmask;
1903 		sb->max_dev = cpu_to_le32(max_dev);
1904 		rdev->sb_size = max_dev * 2 + 256;
1905 		bmask = queue_logical_block_size(rdev->bdev->bd_disk->queue)-1;
1906 		if (rdev->sb_size & bmask)
1907 			rdev->sb_size = (rdev->sb_size | bmask) + 1;
1908 	} else
1909 		max_dev = le32_to_cpu(sb->max_dev);
1910 
1911 	for (i=0; i<max_dev;i++)
1912 		sb->dev_roles[i] = cpu_to_le16(0xfffe);
1913 
1914 	rdev_for_each(rdev2, mddev) {
1915 		i = rdev2->desc_nr;
1916 		if (test_bit(Faulty, &rdev2->flags))
1917 			sb->dev_roles[i] = cpu_to_le16(0xfffe);
1918 		else if (test_bit(In_sync, &rdev2->flags))
1919 			sb->dev_roles[i] = cpu_to_le16(rdev2->raid_disk);
1920 		else if (rdev2->raid_disk >= 0)
1921 			sb->dev_roles[i] = cpu_to_le16(rdev2->raid_disk);
1922 		else
1923 			sb->dev_roles[i] = cpu_to_le16(0xffff);
1924 	}
1925 
1926 	sb->sb_csum = calc_sb_1_csum(sb);
1927 }
1928 
1929 static unsigned long long
1930 super_1_rdev_size_change(struct md_rdev *rdev, sector_t num_sectors)
1931 {
1932 	struct mdp_superblock_1 *sb;
1933 	sector_t max_sectors;
1934 	if (num_sectors && num_sectors < rdev->mddev->dev_sectors)
1935 		return 0; /* component must fit device */
1936 	if (rdev->data_offset != rdev->new_data_offset)
1937 		return 0; /* too confusing */
1938 	if (rdev->sb_start < rdev->data_offset) {
1939 		/* minor versions 1 and 2; superblock before data */
1940 		max_sectors = i_size_read(rdev->bdev->bd_inode) >> 9;
1941 		max_sectors -= rdev->data_offset;
1942 		if (!num_sectors || num_sectors > max_sectors)
1943 			num_sectors = max_sectors;
1944 	} else if (rdev->mddev->bitmap_info.offset) {
1945 		/* minor version 0 with bitmap we can't move */
1946 		return 0;
1947 	} else {
1948 		/* minor version 0; superblock after data */
1949 		sector_t sb_start;
1950 		sb_start = (i_size_read(rdev->bdev->bd_inode) >> 9) - 8*2;
1951 		sb_start &= ~(sector_t)(4*2 - 1);
1952 		max_sectors = rdev->sectors + sb_start - rdev->sb_start;
1953 		if (!num_sectors || num_sectors > max_sectors)
1954 			num_sectors = max_sectors;
1955 		rdev->sb_start = sb_start;
1956 	}
1957 	sb = page_address(rdev->sb_page);
1958 	sb->data_size = cpu_to_le64(num_sectors);
1959 	sb->super_offset = rdev->sb_start;
1960 	sb->sb_csum = calc_sb_1_csum(sb);
1961 	md_super_write(rdev->mddev, rdev, rdev->sb_start, rdev->sb_size,
1962 		       rdev->sb_page);
1963 	md_super_wait(rdev->mddev);
1964 	return num_sectors;
1965 
1966 }
1967 
1968 static int
1969 super_1_allow_new_offset(struct md_rdev *rdev,
1970 			 unsigned long long new_offset)
1971 {
1972 	/* All necessary checks on new >= old have been done */
1973 	struct bitmap *bitmap;
1974 	if (new_offset >= rdev->data_offset)
1975 		return 1;
1976 
1977 	/* with 1.0 metadata, there is no metadata to tread on
1978 	 * so we can always move back */
1979 	if (rdev->mddev->minor_version == 0)
1980 		return 1;
1981 
1982 	/* otherwise we must be sure not to step on
1983 	 * any metadata, so stay:
1984 	 * 36K beyond start of superblock
1985 	 * beyond end of badblocks
1986 	 * beyond write-intent bitmap
1987 	 */
1988 	if (rdev->sb_start + (32+4)*2 > new_offset)
1989 		return 0;
1990 	bitmap = rdev->mddev->bitmap;
1991 	if (bitmap && !rdev->mddev->bitmap_info.file &&
1992 	    rdev->sb_start + rdev->mddev->bitmap_info.offset +
1993 	    bitmap->storage.file_pages * (PAGE_SIZE>>9) > new_offset)
1994 		return 0;
1995 	if (rdev->badblocks.sector + rdev->badblocks.size > new_offset)
1996 		return 0;
1997 
1998 	return 1;
1999 }
2000 
2001 static struct super_type super_types[] = {
2002 	[0] = {
2003 		.name	= "0.90.0",
2004 		.owner	= THIS_MODULE,
2005 		.load_super	    = super_90_load,
2006 		.validate_super	    = super_90_validate,
2007 		.sync_super	    = super_90_sync,
2008 		.rdev_size_change   = super_90_rdev_size_change,
2009 		.allow_new_offset   = super_90_allow_new_offset,
2010 	},
2011 	[1] = {
2012 		.name	= "md-1",
2013 		.owner	= THIS_MODULE,
2014 		.load_super	    = super_1_load,
2015 		.validate_super	    = super_1_validate,
2016 		.sync_super	    = super_1_sync,
2017 		.rdev_size_change   = super_1_rdev_size_change,
2018 		.allow_new_offset   = super_1_allow_new_offset,
2019 	},
2020 };
2021 
2022 static void sync_super(struct mddev *mddev, struct md_rdev *rdev)
2023 {
2024 	if (mddev->sync_super) {
2025 		mddev->sync_super(mddev, rdev);
2026 		return;
2027 	}
2028 
2029 	BUG_ON(mddev->major_version >= ARRAY_SIZE(super_types));
2030 
2031 	super_types[mddev->major_version].sync_super(mddev, rdev);
2032 }
2033 
2034 static int match_mddev_units(struct mddev *mddev1, struct mddev *mddev2)
2035 {
2036 	struct md_rdev *rdev, *rdev2;
2037 
2038 	rcu_read_lock();
2039 	rdev_for_each_rcu(rdev, mddev1)
2040 		rdev_for_each_rcu(rdev2, mddev2)
2041 			if (rdev->bdev->bd_contains ==
2042 			    rdev2->bdev->bd_contains) {
2043 				rcu_read_unlock();
2044 				return 1;
2045 			}
2046 	rcu_read_unlock();
2047 	return 0;
2048 }
2049 
2050 static LIST_HEAD(pending_raid_disks);
2051 
2052 /*
2053  * Try to register data integrity profile for an mddev
2054  *
2055  * This is called when an array is started and after a disk has been kicked
2056  * from the array. It only succeeds if all working and active component devices
2057  * are integrity capable with matching profiles.
2058  */
2059 int md_integrity_register(struct mddev *mddev)
2060 {
2061 	struct md_rdev *rdev, *reference = NULL;
2062 
2063 	if (list_empty(&mddev->disks))
2064 		return 0; /* nothing to do */
2065 	if (!mddev->gendisk || blk_get_integrity(mddev->gendisk))
2066 		return 0; /* shouldn't register, or already is */
2067 	rdev_for_each(rdev, mddev) {
2068 		/* skip spares and non-functional disks */
2069 		if (test_bit(Faulty, &rdev->flags))
2070 			continue;
2071 		if (rdev->raid_disk < 0)
2072 			continue;
2073 		if (!reference) {
2074 			/* Use the first rdev as the reference */
2075 			reference = rdev;
2076 			continue;
2077 		}
2078 		/* does this rdev's profile match the reference profile? */
2079 		if (blk_integrity_compare(reference->bdev->bd_disk,
2080 				rdev->bdev->bd_disk) < 0)
2081 			return -EINVAL;
2082 	}
2083 	if (!reference || !bdev_get_integrity(reference->bdev))
2084 		return 0;
2085 	/*
2086 	 * All component devices are integrity capable and have matching
2087 	 * profiles, register the common profile for the md device.
2088 	 */
2089 	if (blk_integrity_register(mddev->gendisk,
2090 			bdev_get_integrity(reference->bdev)) != 0) {
2091 		printk(KERN_ERR "md: failed to register integrity for %s\n",
2092 			mdname(mddev));
2093 		return -EINVAL;
2094 	}
2095 	printk(KERN_NOTICE "md: data integrity enabled on %s\n", mdname(mddev));
2096 	if (bioset_integrity_create(mddev->bio_set, BIO_POOL_SIZE)) {
2097 		printk(KERN_ERR "md: failed to create integrity pool for %s\n",
2098 		       mdname(mddev));
2099 		return -EINVAL;
2100 	}
2101 	return 0;
2102 }
2103 EXPORT_SYMBOL(md_integrity_register);
2104 
2105 /* Disable data integrity if non-capable/non-matching disk is being added */
2106 void md_integrity_add_rdev(struct md_rdev *rdev, struct mddev *mddev)
2107 {
2108 	struct blk_integrity *bi_rdev = bdev_get_integrity(rdev->bdev);
2109 	struct blk_integrity *bi_mddev = blk_get_integrity(mddev->gendisk);
2110 
2111 	if (!bi_mddev) /* nothing to do */
2112 		return;
2113 	if (rdev->raid_disk < 0) /* skip spares */
2114 		return;
2115 	if (bi_rdev && blk_integrity_compare(mddev->gendisk,
2116 					     rdev->bdev->bd_disk) >= 0)
2117 		return;
2118 	printk(KERN_NOTICE "disabling data integrity on %s\n", mdname(mddev));
2119 	blk_integrity_unregister(mddev->gendisk);
2120 }
2121 EXPORT_SYMBOL(md_integrity_add_rdev);
2122 
2123 static int bind_rdev_to_array(struct md_rdev * rdev, struct mddev * mddev)
2124 {
2125 	char b[BDEVNAME_SIZE];
2126 	struct kobject *ko;
2127 	char *s;
2128 	int err;
2129 
2130 	if (rdev->mddev) {
2131 		MD_BUG();
2132 		return -EINVAL;
2133 	}
2134 
2135 	/* prevent duplicates */
2136 	if (find_rdev(mddev, rdev->bdev->bd_dev))
2137 		return -EEXIST;
2138 
2139 	/* make sure rdev->sectors exceeds mddev->dev_sectors */
2140 	if (rdev->sectors && (mddev->dev_sectors == 0 ||
2141 			rdev->sectors < mddev->dev_sectors)) {
2142 		if (mddev->pers) {
2143 			/* Cannot change size, so fail
2144 			 * If mddev->level <= 0, then we don't care
2145 			 * about aligning sizes (e.g. linear)
2146 			 */
2147 			if (mddev->level > 0)
2148 				return -ENOSPC;
2149 		} else
2150 			mddev->dev_sectors = rdev->sectors;
2151 	}
2152 
2153 	/* Verify rdev->desc_nr is unique.
2154 	 * If it is -1, assign a free number, else
2155 	 * check number is not in use
2156 	 */
2157 	if (rdev->desc_nr < 0) {
2158 		int choice = 0;
2159 		if (mddev->pers) choice = mddev->raid_disks;
2160 		while (find_rdev_nr(mddev, choice))
2161 			choice++;
2162 		rdev->desc_nr = choice;
2163 	} else {
2164 		if (find_rdev_nr(mddev, rdev->desc_nr))
2165 			return -EBUSY;
2166 	}
2167 	if (mddev->max_disks && rdev->desc_nr >= mddev->max_disks) {
2168 		printk(KERN_WARNING "md: %s: array is limited to %d devices\n",
2169 		       mdname(mddev), mddev->max_disks);
2170 		return -EBUSY;
2171 	}
2172 	bdevname(rdev->bdev,b);
2173 	while ( (s=strchr(b, '/')) != NULL)
2174 		*s = '!';
2175 
2176 	rdev->mddev = mddev;
2177 	printk(KERN_INFO "md: bind<%s>\n", b);
2178 
2179 	if ((err = kobject_add(&rdev->kobj, &mddev->kobj, "dev-%s", b)))
2180 		goto fail;
2181 
2182 	ko = &part_to_dev(rdev->bdev->bd_part)->kobj;
2183 	if (sysfs_create_link(&rdev->kobj, ko, "block"))
2184 		/* failure here is OK */;
2185 	rdev->sysfs_state = sysfs_get_dirent_safe(rdev->kobj.sd, "state");
2186 
2187 	list_add_rcu(&rdev->same_set, &mddev->disks);
2188 	bd_link_disk_holder(rdev->bdev, mddev->gendisk);
2189 
2190 	/* May as well allow recovery to be retried once */
2191 	mddev->recovery_disabled++;
2192 
2193 	return 0;
2194 
2195  fail:
2196 	printk(KERN_WARNING "md: failed to register dev-%s for %s\n",
2197 	       b, mdname(mddev));
2198 	return err;
2199 }
2200 
2201 static void md_delayed_delete(struct work_struct *ws)
2202 {
2203 	struct md_rdev *rdev = container_of(ws, struct md_rdev, del_work);
2204 	kobject_del(&rdev->kobj);
2205 	kobject_put(&rdev->kobj);
2206 }
2207 
2208 static void unbind_rdev_from_array(struct md_rdev * rdev)
2209 {
2210 	char b[BDEVNAME_SIZE];
2211 	if (!rdev->mddev) {
2212 		MD_BUG();
2213 		return;
2214 	}
2215 	bd_unlink_disk_holder(rdev->bdev, rdev->mddev->gendisk);
2216 	list_del_rcu(&rdev->same_set);
2217 	printk(KERN_INFO "md: unbind<%s>\n", bdevname(rdev->bdev,b));
2218 	rdev->mddev = NULL;
2219 	sysfs_remove_link(&rdev->kobj, "block");
2220 	sysfs_put(rdev->sysfs_state);
2221 	rdev->sysfs_state = NULL;
2222 	rdev->badblocks.count = 0;
2223 	/* We need to delay this, otherwise we can deadlock when
2224 	 * writing to 'remove' to "dev/state".  We also need
2225 	 * to delay it due to rcu usage.
2226 	 */
2227 	synchronize_rcu();
2228 	INIT_WORK(&rdev->del_work, md_delayed_delete);
2229 	kobject_get(&rdev->kobj);
2230 	queue_work(md_misc_wq, &rdev->del_work);
2231 }
2232 
2233 /*
2234  * prevent the device from being mounted, repartitioned or
2235  * otherwise reused by a RAID array (or any other kernel
2236  * subsystem), by bd_claiming the device.
2237  */
2238 static int lock_rdev(struct md_rdev *rdev, dev_t dev, int shared)
2239 {
2240 	int err = 0;
2241 	struct block_device *bdev;
2242 	char b[BDEVNAME_SIZE];
2243 
2244 	bdev = blkdev_get_by_dev(dev, FMODE_READ|FMODE_WRITE|FMODE_EXCL,
2245 				 shared ? (struct md_rdev *)lock_rdev : rdev);
2246 	if (IS_ERR(bdev)) {
2247 		printk(KERN_ERR "md: could not open %s.\n",
2248 			__bdevname(dev, b));
2249 		return PTR_ERR(bdev);
2250 	}
2251 	rdev->bdev = bdev;
2252 	return err;
2253 }
2254 
2255 static void unlock_rdev(struct md_rdev *rdev)
2256 {
2257 	struct block_device *bdev = rdev->bdev;
2258 	rdev->bdev = NULL;
2259 	if (!bdev)
2260 		MD_BUG();
2261 	blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
2262 }
2263 
2264 void md_autodetect_dev(dev_t dev);
2265 
2266 static void export_rdev(struct md_rdev * rdev)
2267 {
2268 	char b[BDEVNAME_SIZE];
2269 	printk(KERN_INFO "md: export_rdev(%s)\n",
2270 		bdevname(rdev->bdev,b));
2271 	if (rdev->mddev)
2272 		MD_BUG();
2273 	md_rdev_clear(rdev);
2274 #ifndef MODULE
2275 	if (test_bit(AutoDetected, &rdev->flags))
2276 		md_autodetect_dev(rdev->bdev->bd_dev);
2277 #endif
2278 	unlock_rdev(rdev);
2279 	kobject_put(&rdev->kobj);
2280 }
2281 
2282 static void kick_rdev_from_array(struct md_rdev * rdev)
2283 {
2284 	unbind_rdev_from_array(rdev);
2285 	export_rdev(rdev);
2286 }
2287 
2288 static void export_array(struct mddev *mddev)
2289 {
2290 	struct md_rdev *rdev, *tmp;
2291 
2292 	rdev_for_each_safe(rdev, tmp, mddev) {
2293 		if (!rdev->mddev) {
2294 			MD_BUG();
2295 			continue;
2296 		}
2297 		kick_rdev_from_array(rdev);
2298 	}
2299 	if (!list_empty(&mddev->disks))
2300 		MD_BUG();
2301 	mddev->raid_disks = 0;
2302 	mddev->major_version = 0;
2303 }
2304 
2305 static void print_desc(mdp_disk_t *desc)
2306 {
2307 	printk(" DISK<N:%d,(%d,%d),R:%d,S:%d>\n", desc->number,
2308 		desc->major,desc->minor,desc->raid_disk,desc->state);
2309 }
2310 
2311 static void print_sb_90(mdp_super_t *sb)
2312 {
2313 	int i;
2314 
2315 	printk(KERN_INFO
2316 		"md:  SB: (V:%d.%d.%d) ID:<%08x.%08x.%08x.%08x> CT:%08x\n",
2317 		sb->major_version, sb->minor_version, sb->patch_version,
2318 		sb->set_uuid0, sb->set_uuid1, sb->set_uuid2, sb->set_uuid3,
2319 		sb->ctime);
2320 	printk(KERN_INFO "md:     L%d S%08d ND:%d RD:%d md%d LO:%d CS:%d\n",
2321 		sb->level, sb->size, sb->nr_disks, sb->raid_disks,
2322 		sb->md_minor, sb->layout, sb->chunk_size);
2323 	printk(KERN_INFO "md:     UT:%08x ST:%d AD:%d WD:%d"
2324 		" FD:%d SD:%d CSUM:%08x E:%08lx\n",
2325 		sb->utime, sb->state, sb->active_disks, sb->working_disks,
2326 		sb->failed_disks, sb->spare_disks,
2327 		sb->sb_csum, (unsigned long)sb->events_lo);
2328 
2329 	printk(KERN_INFO);
2330 	for (i = 0; i < MD_SB_DISKS; i++) {
2331 		mdp_disk_t *desc;
2332 
2333 		desc = sb->disks + i;
2334 		if (desc->number || desc->major || desc->minor ||
2335 		    desc->raid_disk || (desc->state && (desc->state != 4))) {
2336 			printk("     D %2d: ", i);
2337 			print_desc(desc);
2338 		}
2339 	}
2340 	printk(KERN_INFO "md:     THIS: ");
2341 	print_desc(&sb->this_disk);
2342 }
2343 
2344 static void print_sb_1(struct mdp_superblock_1 *sb)
2345 {
2346 	__u8 *uuid;
2347 
2348 	uuid = sb->set_uuid;
2349 	printk(KERN_INFO
2350 	       "md:  SB: (V:%u) (F:0x%08x) Array-ID:<%pU>\n"
2351 	       "md:    Name: \"%s\" CT:%llu\n",
2352 		le32_to_cpu(sb->major_version),
2353 		le32_to_cpu(sb->feature_map),
2354 		uuid,
2355 		sb->set_name,
2356 		(unsigned long long)le64_to_cpu(sb->ctime)
2357 		       & MD_SUPERBLOCK_1_TIME_SEC_MASK);
2358 
2359 	uuid = sb->device_uuid;
2360 	printk(KERN_INFO
2361 	       "md:       L%u SZ%llu RD:%u LO:%u CS:%u DO:%llu DS:%llu SO:%llu"
2362 			" RO:%llu\n"
2363 	       "md:     Dev:%08x UUID: %pU\n"
2364 	       "md:       (F:0x%08x) UT:%llu Events:%llu ResyncOffset:%llu CSUM:0x%08x\n"
2365 	       "md:         (MaxDev:%u) \n",
2366 		le32_to_cpu(sb->level),
2367 		(unsigned long long)le64_to_cpu(sb->size),
2368 		le32_to_cpu(sb->raid_disks),
2369 		le32_to_cpu(sb->layout),
2370 		le32_to_cpu(sb->chunksize),
2371 		(unsigned long long)le64_to_cpu(sb->data_offset),
2372 		(unsigned long long)le64_to_cpu(sb->data_size),
2373 		(unsigned long long)le64_to_cpu(sb->super_offset),
2374 		(unsigned long long)le64_to_cpu(sb->recovery_offset),
2375 		le32_to_cpu(sb->dev_number),
2376 		uuid,
2377 		sb->devflags,
2378 		(unsigned long long)le64_to_cpu(sb->utime) & MD_SUPERBLOCK_1_TIME_SEC_MASK,
2379 		(unsigned long long)le64_to_cpu(sb->events),
2380 		(unsigned long long)le64_to_cpu(sb->resync_offset),
2381 		le32_to_cpu(sb->sb_csum),
2382 		le32_to_cpu(sb->max_dev)
2383 		);
2384 }
2385 
2386 static void print_rdev(struct md_rdev *rdev, int major_version)
2387 {
2388 	char b[BDEVNAME_SIZE];
2389 	printk(KERN_INFO "md: rdev %s, Sect:%08llu F:%d S:%d DN:%u\n",
2390 		bdevname(rdev->bdev, b), (unsigned long long)rdev->sectors,
2391 	        test_bit(Faulty, &rdev->flags), test_bit(In_sync, &rdev->flags),
2392 	        rdev->desc_nr);
2393 	if (rdev->sb_loaded) {
2394 		printk(KERN_INFO "md: rdev superblock (MJ:%d):\n", major_version);
2395 		switch (major_version) {
2396 		case 0:
2397 			print_sb_90(page_address(rdev->sb_page));
2398 			break;
2399 		case 1:
2400 			print_sb_1(page_address(rdev->sb_page));
2401 			break;
2402 		}
2403 	} else
2404 		printk(KERN_INFO "md: no rdev superblock!\n");
2405 }
2406 
2407 static void md_print_devices(void)
2408 {
2409 	struct list_head *tmp;
2410 	struct md_rdev *rdev;
2411 	struct mddev *mddev;
2412 	char b[BDEVNAME_SIZE];
2413 
2414 	printk("\n");
2415 	printk("md:	**********************************\n");
2416 	printk("md:	* <COMPLETE RAID STATE PRINTOUT> *\n");
2417 	printk("md:	**********************************\n");
2418 	for_each_mddev(mddev, tmp) {
2419 
2420 		if (mddev->bitmap)
2421 			bitmap_print_sb(mddev->bitmap);
2422 		else
2423 			printk("%s: ", mdname(mddev));
2424 		rdev_for_each(rdev, mddev)
2425 			printk("<%s>", bdevname(rdev->bdev,b));
2426 		printk("\n");
2427 
2428 		rdev_for_each(rdev, mddev)
2429 			print_rdev(rdev, mddev->major_version);
2430 	}
2431 	printk("md:	**********************************\n");
2432 	printk("\n");
2433 }
2434 
2435 
2436 static void sync_sbs(struct mddev * mddev, int nospares)
2437 {
2438 	/* Update each superblock (in-memory image), but
2439 	 * if we are allowed to, skip spares which already
2440 	 * have the right event counter, or have one earlier
2441 	 * (which would mean they aren't being marked as dirty
2442 	 * with the rest of the array)
2443 	 */
2444 	struct md_rdev *rdev;
2445 	rdev_for_each(rdev, mddev) {
2446 		if (rdev->sb_events == mddev->events ||
2447 		    (nospares &&
2448 		     rdev->raid_disk < 0 &&
2449 		     rdev->sb_events+1 == mddev->events)) {
2450 			/* Don't update this superblock */
2451 			rdev->sb_loaded = 2;
2452 		} else {
2453 			sync_super(mddev, rdev);
2454 			rdev->sb_loaded = 1;
2455 		}
2456 	}
2457 }
2458 
2459 static void md_update_sb(struct mddev * mddev, int force_change)
2460 {
2461 	struct md_rdev *rdev;
2462 	int sync_req;
2463 	int nospares = 0;
2464 	int any_badblocks_changed = 0;
2465 
2466 repeat:
2467 	/* First make sure individual recovery_offsets are correct */
2468 	rdev_for_each(rdev, mddev) {
2469 		if (rdev->raid_disk >= 0 &&
2470 		    mddev->delta_disks >= 0 &&
2471 		    !test_bit(In_sync, &rdev->flags) &&
2472 		    mddev->curr_resync_completed > rdev->recovery_offset)
2473 				rdev->recovery_offset = mddev->curr_resync_completed;
2474 
2475 	}
2476 	if (!mddev->persistent) {
2477 		clear_bit(MD_CHANGE_CLEAN, &mddev->flags);
2478 		clear_bit(MD_CHANGE_DEVS, &mddev->flags);
2479 		if (!mddev->external) {
2480 			clear_bit(MD_CHANGE_PENDING, &mddev->flags);
2481 			rdev_for_each(rdev, mddev) {
2482 				if (rdev->badblocks.changed) {
2483 					rdev->badblocks.changed = 0;
2484 					md_ack_all_badblocks(&rdev->badblocks);
2485 					md_error(mddev, rdev);
2486 				}
2487 				clear_bit(Blocked, &rdev->flags);
2488 				clear_bit(BlockedBadBlocks, &rdev->flags);
2489 				wake_up(&rdev->blocked_wait);
2490 			}
2491 		}
2492 		wake_up(&mddev->sb_wait);
2493 		return;
2494 	}
2495 
2496 	spin_lock_irq(&mddev->write_lock);
2497 
2498 	mddev->utime = get_seconds();
2499 
2500 	if (test_and_clear_bit(MD_CHANGE_DEVS, &mddev->flags))
2501 		force_change = 1;
2502 	if (test_and_clear_bit(MD_CHANGE_CLEAN, &mddev->flags))
2503 		/* just a clean<-> dirty transition, possibly leave spares alone,
2504 		 * though if events isn't the right even/odd, we will have to do
2505 		 * spares after all
2506 		 */
2507 		nospares = 1;
2508 	if (force_change)
2509 		nospares = 0;
2510 	if (mddev->degraded)
2511 		/* If the array is degraded, then skipping spares is both
2512 		 * dangerous and fairly pointless.
2513 		 * Dangerous because a device that was removed from the array
2514 		 * might have a event_count that still looks up-to-date,
2515 		 * so it can be re-added without a resync.
2516 		 * Pointless because if there are any spares to skip,
2517 		 * then a recovery will happen and soon that array won't
2518 		 * be degraded any more and the spare can go back to sleep then.
2519 		 */
2520 		nospares = 0;
2521 
2522 	sync_req = mddev->in_sync;
2523 
2524 	/* If this is just a dirty<->clean transition, and the array is clean
2525 	 * and 'events' is odd, we can roll back to the previous clean state */
2526 	if (nospares
2527 	    && (mddev->in_sync && mddev->recovery_cp == MaxSector)
2528 	    && mddev->can_decrease_events
2529 	    && mddev->events != 1) {
2530 		mddev->events--;
2531 		mddev->can_decrease_events = 0;
2532 	} else {
2533 		/* otherwise we have to go forward and ... */
2534 		mddev->events ++;
2535 		mddev->can_decrease_events = nospares;
2536 	}
2537 
2538 	if (!mddev->events) {
2539 		/*
2540 		 * oops, this 64-bit counter should never wrap.
2541 		 * Either we are in around ~1 trillion A.C., assuming
2542 		 * 1 reboot per second, or we have a bug:
2543 		 */
2544 		MD_BUG();
2545 		mddev->events --;
2546 	}
2547 
2548 	rdev_for_each(rdev, mddev) {
2549 		if (rdev->badblocks.changed)
2550 			any_badblocks_changed++;
2551 		if (test_bit(Faulty, &rdev->flags))
2552 			set_bit(FaultRecorded, &rdev->flags);
2553 	}
2554 
2555 	sync_sbs(mddev, nospares);
2556 	spin_unlock_irq(&mddev->write_lock);
2557 
2558 	pr_debug("md: updating %s RAID superblock on device (in sync %d)\n",
2559 		 mdname(mddev), mddev->in_sync);
2560 
2561 	bitmap_update_sb(mddev->bitmap);
2562 	rdev_for_each(rdev, mddev) {
2563 		char b[BDEVNAME_SIZE];
2564 
2565 		if (rdev->sb_loaded != 1)
2566 			continue; /* no noise on spare devices */
2567 
2568 		if (!test_bit(Faulty, &rdev->flags) &&
2569 		    rdev->saved_raid_disk == -1) {
2570 			md_super_write(mddev,rdev,
2571 				       rdev->sb_start, rdev->sb_size,
2572 				       rdev->sb_page);
2573 			pr_debug("md: (write) %s's sb offset: %llu\n",
2574 				 bdevname(rdev->bdev, b),
2575 				 (unsigned long long)rdev->sb_start);
2576 			rdev->sb_events = mddev->events;
2577 			if (rdev->badblocks.size) {
2578 				md_super_write(mddev, rdev,
2579 					       rdev->badblocks.sector,
2580 					       rdev->badblocks.size << 9,
2581 					       rdev->bb_page);
2582 				rdev->badblocks.size = 0;
2583 			}
2584 
2585 		} else if (test_bit(Faulty, &rdev->flags))
2586 			pr_debug("md: %s (skipping faulty)\n",
2587 				 bdevname(rdev->bdev, b));
2588 		else
2589 			pr_debug("(skipping incremental s/r ");
2590 
2591 		if (mddev->level == LEVEL_MULTIPATH)
2592 			/* only need to write one superblock... */
2593 			break;
2594 	}
2595 	md_super_wait(mddev);
2596 	/* if there was a failure, MD_CHANGE_DEVS was set, and we re-write super */
2597 
2598 	spin_lock_irq(&mddev->write_lock);
2599 	if (mddev->in_sync != sync_req ||
2600 	    test_bit(MD_CHANGE_DEVS, &mddev->flags)) {
2601 		/* have to write it out again */
2602 		spin_unlock_irq(&mddev->write_lock);
2603 		goto repeat;
2604 	}
2605 	clear_bit(MD_CHANGE_PENDING, &mddev->flags);
2606 	spin_unlock_irq(&mddev->write_lock);
2607 	wake_up(&mddev->sb_wait);
2608 	if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
2609 		sysfs_notify(&mddev->kobj, NULL, "sync_completed");
2610 
2611 	rdev_for_each(rdev, mddev) {
2612 		if (test_and_clear_bit(FaultRecorded, &rdev->flags))
2613 			clear_bit(Blocked, &rdev->flags);
2614 
2615 		if (any_badblocks_changed)
2616 			md_ack_all_badblocks(&rdev->badblocks);
2617 		clear_bit(BlockedBadBlocks, &rdev->flags);
2618 		wake_up(&rdev->blocked_wait);
2619 	}
2620 }
2621 
2622 /* words written to sysfs files may, or may not, be \n terminated.
2623  * We want to accept with case. For this we use cmd_match.
2624  */
2625 static int cmd_match(const char *cmd, const char *str)
2626 {
2627 	/* See if cmd, written into a sysfs file, matches
2628 	 * str.  They must either be the same, or cmd can
2629 	 * have a trailing newline
2630 	 */
2631 	while (*cmd && *str && *cmd == *str) {
2632 		cmd++;
2633 		str++;
2634 	}
2635 	if (*cmd == '\n')
2636 		cmd++;
2637 	if (*str || *cmd)
2638 		return 0;
2639 	return 1;
2640 }
2641 
2642 struct rdev_sysfs_entry {
2643 	struct attribute attr;
2644 	ssize_t (*show)(struct md_rdev *, char *);
2645 	ssize_t (*store)(struct md_rdev *, const char *, size_t);
2646 };
2647 
2648 static ssize_t
2649 state_show(struct md_rdev *rdev, char *page)
2650 {
2651 	char *sep = "";
2652 	size_t len = 0;
2653 
2654 	if (test_bit(Faulty, &rdev->flags) ||
2655 	    rdev->badblocks.unacked_exist) {
2656 		len+= sprintf(page+len, "%sfaulty",sep);
2657 		sep = ",";
2658 	}
2659 	if (test_bit(In_sync, &rdev->flags)) {
2660 		len += sprintf(page+len, "%sin_sync",sep);
2661 		sep = ",";
2662 	}
2663 	if (test_bit(WriteMostly, &rdev->flags)) {
2664 		len += sprintf(page+len, "%swrite_mostly",sep);
2665 		sep = ",";
2666 	}
2667 	if (test_bit(Blocked, &rdev->flags) ||
2668 	    (rdev->badblocks.unacked_exist
2669 	     && !test_bit(Faulty, &rdev->flags))) {
2670 		len += sprintf(page+len, "%sblocked", sep);
2671 		sep = ",";
2672 	}
2673 	if (!test_bit(Faulty, &rdev->flags) &&
2674 	    !test_bit(In_sync, &rdev->flags)) {
2675 		len += sprintf(page+len, "%sspare", sep);
2676 		sep = ",";
2677 	}
2678 	if (test_bit(WriteErrorSeen, &rdev->flags)) {
2679 		len += sprintf(page+len, "%swrite_error", sep);
2680 		sep = ",";
2681 	}
2682 	if (test_bit(WantReplacement, &rdev->flags)) {
2683 		len += sprintf(page+len, "%swant_replacement", sep);
2684 		sep = ",";
2685 	}
2686 	if (test_bit(Replacement, &rdev->flags)) {
2687 		len += sprintf(page+len, "%sreplacement", sep);
2688 		sep = ",";
2689 	}
2690 
2691 	return len+sprintf(page+len, "\n");
2692 }
2693 
2694 static ssize_t
2695 state_store(struct md_rdev *rdev, const char *buf, size_t len)
2696 {
2697 	/* can write
2698 	 *  faulty  - simulates an error
2699 	 *  remove  - disconnects the device
2700 	 *  writemostly - sets write_mostly
2701 	 *  -writemostly - clears write_mostly
2702 	 *  blocked - sets the Blocked flags
2703 	 *  -blocked - clears the Blocked and possibly simulates an error
2704 	 *  insync - sets Insync providing device isn't active
2705 	 *  write_error - sets WriteErrorSeen
2706 	 *  -write_error - clears WriteErrorSeen
2707 	 */
2708 	int err = -EINVAL;
2709 	if (cmd_match(buf, "faulty") && rdev->mddev->pers) {
2710 		md_error(rdev->mddev, rdev);
2711 		if (test_bit(Faulty, &rdev->flags))
2712 			err = 0;
2713 		else
2714 			err = -EBUSY;
2715 	} else if (cmd_match(buf, "remove")) {
2716 		if (rdev->raid_disk >= 0)
2717 			err = -EBUSY;
2718 		else {
2719 			struct mddev *mddev = rdev->mddev;
2720 			kick_rdev_from_array(rdev);
2721 			if (mddev->pers)
2722 				md_update_sb(mddev, 1);
2723 			md_new_event(mddev);
2724 			err = 0;
2725 		}
2726 	} else if (cmd_match(buf, "writemostly")) {
2727 		set_bit(WriteMostly, &rdev->flags);
2728 		err = 0;
2729 	} else if (cmd_match(buf, "-writemostly")) {
2730 		clear_bit(WriteMostly, &rdev->flags);
2731 		err = 0;
2732 	} else if (cmd_match(buf, "blocked")) {
2733 		set_bit(Blocked, &rdev->flags);
2734 		err = 0;
2735 	} else if (cmd_match(buf, "-blocked")) {
2736 		if (!test_bit(Faulty, &rdev->flags) &&
2737 		    rdev->badblocks.unacked_exist) {
2738 			/* metadata handler doesn't understand badblocks,
2739 			 * so we need to fail the device
2740 			 */
2741 			md_error(rdev->mddev, rdev);
2742 		}
2743 		clear_bit(Blocked, &rdev->flags);
2744 		clear_bit(BlockedBadBlocks, &rdev->flags);
2745 		wake_up(&rdev->blocked_wait);
2746 		set_bit(MD_RECOVERY_NEEDED, &rdev->mddev->recovery);
2747 		md_wakeup_thread(rdev->mddev->thread);
2748 
2749 		err = 0;
2750 	} else if (cmd_match(buf, "insync") && rdev->raid_disk == -1) {
2751 		set_bit(In_sync, &rdev->flags);
2752 		err = 0;
2753 	} else if (cmd_match(buf, "write_error")) {
2754 		set_bit(WriteErrorSeen, &rdev->flags);
2755 		err = 0;
2756 	} else if (cmd_match(buf, "-write_error")) {
2757 		clear_bit(WriteErrorSeen, &rdev->flags);
2758 		err = 0;
2759 	} else if (cmd_match(buf, "want_replacement")) {
2760 		/* Any non-spare device that is not a replacement can
2761 		 * become want_replacement at any time, but we then need to
2762 		 * check if recovery is needed.
2763 		 */
2764 		if (rdev->raid_disk >= 0 &&
2765 		    !test_bit(Replacement, &rdev->flags))
2766 			set_bit(WantReplacement, &rdev->flags);
2767 		set_bit(MD_RECOVERY_NEEDED, &rdev->mddev->recovery);
2768 		md_wakeup_thread(rdev->mddev->thread);
2769 		err = 0;
2770 	} else if (cmd_match(buf, "-want_replacement")) {
2771 		/* Clearing 'want_replacement' is always allowed.
2772 		 * Once replacements starts it is too late though.
2773 		 */
2774 		err = 0;
2775 		clear_bit(WantReplacement, &rdev->flags);
2776 	} else if (cmd_match(buf, "replacement")) {
2777 		/* Can only set a device as a replacement when array has not
2778 		 * yet been started.  Once running, replacement is automatic
2779 		 * from spares, or by assigning 'slot'.
2780 		 */
2781 		if (rdev->mddev->pers)
2782 			err = -EBUSY;
2783 		else {
2784 			set_bit(Replacement, &rdev->flags);
2785 			err = 0;
2786 		}
2787 	} else if (cmd_match(buf, "-replacement")) {
2788 		/* Similarly, can only clear Replacement before start */
2789 		if (rdev->mddev->pers)
2790 			err = -EBUSY;
2791 		else {
2792 			clear_bit(Replacement, &rdev->flags);
2793 			err = 0;
2794 		}
2795 	}
2796 	if (!err)
2797 		sysfs_notify_dirent_safe(rdev->sysfs_state);
2798 	return err ? err : len;
2799 }
2800 static struct rdev_sysfs_entry rdev_state =
2801 __ATTR(state, S_IRUGO|S_IWUSR, state_show, state_store);
2802 
2803 static ssize_t
2804 errors_show(struct md_rdev *rdev, char *page)
2805 {
2806 	return sprintf(page, "%d\n", atomic_read(&rdev->corrected_errors));
2807 }
2808 
2809 static ssize_t
2810 errors_store(struct md_rdev *rdev, const char *buf, size_t len)
2811 {
2812 	char *e;
2813 	unsigned long n = simple_strtoul(buf, &e, 10);
2814 	if (*buf && (*e == 0 || *e == '\n')) {
2815 		atomic_set(&rdev->corrected_errors, n);
2816 		return len;
2817 	}
2818 	return -EINVAL;
2819 }
2820 static struct rdev_sysfs_entry rdev_errors =
2821 __ATTR(errors, S_IRUGO|S_IWUSR, errors_show, errors_store);
2822 
2823 static ssize_t
2824 slot_show(struct md_rdev *rdev, char *page)
2825 {
2826 	if (rdev->raid_disk < 0)
2827 		return sprintf(page, "none\n");
2828 	else
2829 		return sprintf(page, "%d\n", rdev->raid_disk);
2830 }
2831 
2832 static ssize_t
2833 slot_store(struct md_rdev *rdev, const char *buf, size_t len)
2834 {
2835 	char *e;
2836 	int err;
2837 	int slot = simple_strtoul(buf, &e, 10);
2838 	if (strncmp(buf, "none", 4)==0)
2839 		slot = -1;
2840 	else if (e==buf || (*e && *e!= '\n'))
2841 		return -EINVAL;
2842 	if (rdev->mddev->pers && slot == -1) {
2843 		/* Setting 'slot' on an active array requires also
2844 		 * updating the 'rd%d' link, and communicating
2845 		 * with the personality with ->hot_*_disk.
2846 		 * For now we only support removing
2847 		 * failed/spare devices.  This normally happens automatically,
2848 		 * but not when the metadata is externally managed.
2849 		 */
2850 		if (rdev->raid_disk == -1)
2851 			return -EEXIST;
2852 		/* personality does all needed checks */
2853 		if (rdev->mddev->pers->hot_remove_disk == NULL)
2854 			return -EINVAL;
2855 		err = rdev->mddev->pers->
2856 			hot_remove_disk(rdev->mddev, rdev);
2857 		if (err)
2858 			return err;
2859 		sysfs_unlink_rdev(rdev->mddev, rdev);
2860 		rdev->raid_disk = -1;
2861 		set_bit(MD_RECOVERY_NEEDED, &rdev->mddev->recovery);
2862 		md_wakeup_thread(rdev->mddev->thread);
2863 	} else if (rdev->mddev->pers) {
2864 		/* Activating a spare .. or possibly reactivating
2865 		 * if we ever get bitmaps working here.
2866 		 */
2867 
2868 		if (rdev->raid_disk != -1)
2869 			return -EBUSY;
2870 
2871 		if (test_bit(MD_RECOVERY_RUNNING, &rdev->mddev->recovery))
2872 			return -EBUSY;
2873 
2874 		if (rdev->mddev->pers->hot_add_disk == NULL)
2875 			return -EINVAL;
2876 
2877 		if (slot >= rdev->mddev->raid_disks &&
2878 		    slot >= rdev->mddev->raid_disks + rdev->mddev->delta_disks)
2879 			return -ENOSPC;
2880 
2881 		rdev->raid_disk = slot;
2882 		if (test_bit(In_sync, &rdev->flags))
2883 			rdev->saved_raid_disk = slot;
2884 		else
2885 			rdev->saved_raid_disk = -1;
2886 		clear_bit(In_sync, &rdev->flags);
2887 		err = rdev->mddev->pers->
2888 			hot_add_disk(rdev->mddev, rdev);
2889 		if (err) {
2890 			rdev->raid_disk = -1;
2891 			return err;
2892 		} else
2893 			sysfs_notify_dirent_safe(rdev->sysfs_state);
2894 		if (sysfs_link_rdev(rdev->mddev, rdev))
2895 			/* failure here is OK */;
2896 		/* don't wakeup anyone, leave that to userspace. */
2897 	} else {
2898 		if (slot >= rdev->mddev->raid_disks &&
2899 		    slot >= rdev->mddev->raid_disks + rdev->mddev->delta_disks)
2900 			return -ENOSPC;
2901 		rdev->raid_disk = slot;
2902 		/* assume it is working */
2903 		clear_bit(Faulty, &rdev->flags);
2904 		clear_bit(WriteMostly, &rdev->flags);
2905 		set_bit(In_sync, &rdev->flags);
2906 		sysfs_notify_dirent_safe(rdev->sysfs_state);
2907 	}
2908 	return len;
2909 }
2910 
2911 
2912 static struct rdev_sysfs_entry rdev_slot =
2913 __ATTR(slot, S_IRUGO|S_IWUSR, slot_show, slot_store);
2914 
2915 static ssize_t
2916 offset_show(struct md_rdev *rdev, char *page)
2917 {
2918 	return sprintf(page, "%llu\n", (unsigned long long)rdev->data_offset);
2919 }
2920 
2921 static ssize_t
2922 offset_store(struct md_rdev *rdev, const char *buf, size_t len)
2923 {
2924 	unsigned long long offset;
2925 	if (strict_strtoull(buf, 10, &offset) < 0)
2926 		return -EINVAL;
2927 	if (rdev->mddev->pers && rdev->raid_disk >= 0)
2928 		return -EBUSY;
2929 	if (rdev->sectors && rdev->mddev->external)
2930 		/* Must set offset before size, so overlap checks
2931 		 * can be sane */
2932 		return -EBUSY;
2933 	rdev->data_offset = offset;
2934 	rdev->new_data_offset = offset;
2935 	return len;
2936 }
2937 
2938 static struct rdev_sysfs_entry rdev_offset =
2939 __ATTR(offset, S_IRUGO|S_IWUSR, offset_show, offset_store);
2940 
2941 static ssize_t new_offset_show(struct md_rdev *rdev, char *page)
2942 {
2943 	return sprintf(page, "%llu\n",
2944 		       (unsigned long long)rdev->new_data_offset);
2945 }
2946 
2947 static ssize_t new_offset_store(struct md_rdev *rdev,
2948 				const char *buf, size_t len)
2949 {
2950 	unsigned long long new_offset;
2951 	struct mddev *mddev = rdev->mddev;
2952 
2953 	if (strict_strtoull(buf, 10, &new_offset) < 0)
2954 		return -EINVAL;
2955 
2956 	if (mddev->sync_thread)
2957 		return -EBUSY;
2958 	if (new_offset == rdev->data_offset)
2959 		/* reset is always permitted */
2960 		;
2961 	else if (new_offset > rdev->data_offset) {
2962 		/* must not push array size beyond rdev_sectors */
2963 		if (new_offset - rdev->data_offset
2964 		    + mddev->dev_sectors > rdev->sectors)
2965 				return -E2BIG;
2966 	}
2967 	/* Metadata worries about other space details. */
2968 
2969 	/* decreasing the offset is inconsistent with a backwards
2970 	 * reshape.
2971 	 */
2972 	if (new_offset < rdev->data_offset &&
2973 	    mddev->reshape_backwards)
2974 		return -EINVAL;
2975 	/* Increasing offset is inconsistent with forwards
2976 	 * reshape.  reshape_direction should be set to
2977 	 * 'backwards' first.
2978 	 */
2979 	if (new_offset > rdev->data_offset &&
2980 	    !mddev->reshape_backwards)
2981 		return -EINVAL;
2982 
2983 	if (mddev->pers && mddev->persistent &&
2984 	    !super_types[mddev->major_version]
2985 	    .allow_new_offset(rdev, new_offset))
2986 		return -E2BIG;
2987 	rdev->new_data_offset = new_offset;
2988 	if (new_offset > rdev->data_offset)
2989 		mddev->reshape_backwards = 1;
2990 	else if (new_offset < rdev->data_offset)
2991 		mddev->reshape_backwards = 0;
2992 
2993 	return len;
2994 }
2995 static struct rdev_sysfs_entry rdev_new_offset =
2996 __ATTR(new_offset, S_IRUGO|S_IWUSR, new_offset_show, new_offset_store);
2997 
2998 static ssize_t
2999 rdev_size_show(struct md_rdev *rdev, char *page)
3000 {
3001 	return sprintf(page, "%llu\n", (unsigned long long)rdev->sectors / 2);
3002 }
3003 
3004 static int overlaps(sector_t s1, sector_t l1, sector_t s2, sector_t l2)
3005 {
3006 	/* check if two start/length pairs overlap */
3007 	if (s1+l1 <= s2)
3008 		return 0;
3009 	if (s2+l2 <= s1)
3010 		return 0;
3011 	return 1;
3012 }
3013 
3014 static int strict_blocks_to_sectors(const char *buf, sector_t *sectors)
3015 {
3016 	unsigned long long blocks;
3017 	sector_t new;
3018 
3019 	if (strict_strtoull(buf, 10, &blocks) < 0)
3020 		return -EINVAL;
3021 
3022 	if (blocks & 1ULL << (8 * sizeof(blocks) - 1))
3023 		return -EINVAL; /* sector conversion overflow */
3024 
3025 	new = blocks * 2;
3026 	if (new != blocks * 2)
3027 		return -EINVAL; /* unsigned long long to sector_t overflow */
3028 
3029 	*sectors = new;
3030 	return 0;
3031 }
3032 
3033 static ssize_t
3034 rdev_size_store(struct md_rdev *rdev, const char *buf, size_t len)
3035 {
3036 	struct mddev *my_mddev = rdev->mddev;
3037 	sector_t oldsectors = rdev->sectors;
3038 	sector_t sectors;
3039 
3040 	if (strict_blocks_to_sectors(buf, &sectors) < 0)
3041 		return -EINVAL;
3042 	if (rdev->data_offset != rdev->new_data_offset)
3043 		return -EINVAL; /* too confusing */
3044 	if (my_mddev->pers && rdev->raid_disk >= 0) {
3045 		if (my_mddev->persistent) {
3046 			sectors = super_types[my_mddev->major_version].
3047 				rdev_size_change(rdev, sectors);
3048 			if (!sectors)
3049 				return -EBUSY;
3050 		} else if (!sectors)
3051 			sectors = (i_size_read(rdev->bdev->bd_inode) >> 9) -
3052 				rdev->data_offset;
3053 	}
3054 	if (sectors < my_mddev->dev_sectors)
3055 		return -EINVAL; /* component must fit device */
3056 
3057 	rdev->sectors = sectors;
3058 	if (sectors > oldsectors && my_mddev->external) {
3059 		/* need to check that all other rdevs with the same ->bdev
3060 		 * do not overlap.  We need to unlock the mddev to avoid
3061 		 * a deadlock.  We have already changed rdev->sectors, and if
3062 		 * we have to change it back, we will have the lock again.
3063 		 */
3064 		struct mddev *mddev;
3065 		int overlap = 0;
3066 		struct list_head *tmp;
3067 
3068 		mddev_unlock(my_mddev);
3069 		for_each_mddev(mddev, tmp) {
3070 			struct md_rdev *rdev2;
3071 
3072 			mddev_lock(mddev);
3073 			rdev_for_each(rdev2, mddev)
3074 				if (rdev->bdev == rdev2->bdev &&
3075 				    rdev != rdev2 &&
3076 				    overlaps(rdev->data_offset, rdev->sectors,
3077 					     rdev2->data_offset,
3078 					     rdev2->sectors)) {
3079 					overlap = 1;
3080 					break;
3081 				}
3082 			mddev_unlock(mddev);
3083 			if (overlap) {
3084 				mddev_put(mddev);
3085 				break;
3086 			}
3087 		}
3088 		mddev_lock(my_mddev);
3089 		if (overlap) {
3090 			/* Someone else could have slipped in a size
3091 			 * change here, but doing so is just silly.
3092 			 * We put oldsectors back because we *know* it is
3093 			 * safe, and trust userspace not to race with
3094 			 * itself
3095 			 */
3096 			rdev->sectors = oldsectors;
3097 			return -EBUSY;
3098 		}
3099 	}
3100 	return len;
3101 }
3102 
3103 static struct rdev_sysfs_entry rdev_size =
3104 __ATTR(size, S_IRUGO|S_IWUSR, rdev_size_show, rdev_size_store);
3105 
3106 
3107 static ssize_t recovery_start_show(struct md_rdev *rdev, char *page)
3108 {
3109 	unsigned long long recovery_start = rdev->recovery_offset;
3110 
3111 	if (test_bit(In_sync, &rdev->flags) ||
3112 	    recovery_start == MaxSector)
3113 		return sprintf(page, "none\n");
3114 
3115 	return sprintf(page, "%llu\n", recovery_start);
3116 }
3117 
3118 static ssize_t recovery_start_store(struct md_rdev *rdev, const char *buf, size_t len)
3119 {
3120 	unsigned long long recovery_start;
3121 
3122 	if (cmd_match(buf, "none"))
3123 		recovery_start = MaxSector;
3124 	else if (strict_strtoull(buf, 10, &recovery_start))
3125 		return -EINVAL;
3126 
3127 	if (rdev->mddev->pers &&
3128 	    rdev->raid_disk >= 0)
3129 		return -EBUSY;
3130 
3131 	rdev->recovery_offset = recovery_start;
3132 	if (recovery_start == MaxSector)
3133 		set_bit(In_sync, &rdev->flags);
3134 	else
3135 		clear_bit(In_sync, &rdev->flags);
3136 	return len;
3137 }
3138 
3139 static struct rdev_sysfs_entry rdev_recovery_start =
3140 __ATTR(recovery_start, S_IRUGO|S_IWUSR, recovery_start_show, recovery_start_store);
3141 
3142 
3143 static ssize_t
3144 badblocks_show(struct badblocks *bb, char *page, int unack);
3145 static ssize_t
3146 badblocks_store(struct badblocks *bb, const char *page, size_t len, int unack);
3147 
3148 static ssize_t bb_show(struct md_rdev *rdev, char *page)
3149 {
3150 	return badblocks_show(&rdev->badblocks, page, 0);
3151 }
3152 static ssize_t bb_store(struct md_rdev *rdev, const char *page, size_t len)
3153 {
3154 	int rv = badblocks_store(&rdev->badblocks, page, len, 0);
3155 	/* Maybe that ack was all we needed */
3156 	if (test_and_clear_bit(BlockedBadBlocks, &rdev->flags))
3157 		wake_up(&rdev->blocked_wait);
3158 	return rv;
3159 }
3160 static struct rdev_sysfs_entry rdev_bad_blocks =
3161 __ATTR(bad_blocks, S_IRUGO|S_IWUSR, bb_show, bb_store);
3162 
3163 
3164 static ssize_t ubb_show(struct md_rdev *rdev, char *page)
3165 {
3166 	return badblocks_show(&rdev->badblocks, page, 1);
3167 }
3168 static ssize_t ubb_store(struct md_rdev *rdev, const char *page, size_t len)
3169 {
3170 	return badblocks_store(&rdev->badblocks, page, len, 1);
3171 }
3172 static struct rdev_sysfs_entry rdev_unack_bad_blocks =
3173 __ATTR(unacknowledged_bad_blocks, S_IRUGO|S_IWUSR, ubb_show, ubb_store);
3174 
3175 static struct attribute *rdev_default_attrs[] = {
3176 	&rdev_state.attr,
3177 	&rdev_errors.attr,
3178 	&rdev_slot.attr,
3179 	&rdev_offset.attr,
3180 	&rdev_new_offset.attr,
3181 	&rdev_size.attr,
3182 	&rdev_recovery_start.attr,
3183 	&rdev_bad_blocks.attr,
3184 	&rdev_unack_bad_blocks.attr,
3185 	NULL,
3186 };
3187 static ssize_t
3188 rdev_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
3189 {
3190 	struct rdev_sysfs_entry *entry = container_of(attr, struct rdev_sysfs_entry, attr);
3191 	struct md_rdev *rdev = container_of(kobj, struct md_rdev, kobj);
3192 	struct mddev *mddev = rdev->mddev;
3193 	ssize_t rv;
3194 
3195 	if (!entry->show)
3196 		return -EIO;
3197 
3198 	rv = mddev ? mddev_lock(mddev) : -EBUSY;
3199 	if (!rv) {
3200 		if (rdev->mddev == NULL)
3201 			rv = -EBUSY;
3202 		else
3203 			rv = entry->show(rdev, page);
3204 		mddev_unlock(mddev);
3205 	}
3206 	return rv;
3207 }
3208 
3209 static ssize_t
3210 rdev_attr_store(struct kobject *kobj, struct attribute *attr,
3211 	      const char *page, size_t length)
3212 {
3213 	struct rdev_sysfs_entry *entry = container_of(attr, struct rdev_sysfs_entry, attr);
3214 	struct md_rdev *rdev = container_of(kobj, struct md_rdev, kobj);
3215 	ssize_t rv;
3216 	struct mddev *mddev = rdev->mddev;
3217 
3218 	if (!entry->store)
3219 		return -EIO;
3220 	if (!capable(CAP_SYS_ADMIN))
3221 		return -EACCES;
3222 	rv = mddev ? mddev_lock(mddev): -EBUSY;
3223 	if (!rv) {
3224 		if (rdev->mddev == NULL)
3225 			rv = -EBUSY;
3226 		else
3227 			rv = entry->store(rdev, page, length);
3228 		mddev_unlock(mddev);
3229 	}
3230 	return rv;
3231 }
3232 
3233 static void rdev_free(struct kobject *ko)
3234 {
3235 	struct md_rdev *rdev = container_of(ko, struct md_rdev, kobj);
3236 	kfree(rdev);
3237 }
3238 static const struct sysfs_ops rdev_sysfs_ops = {
3239 	.show		= rdev_attr_show,
3240 	.store		= rdev_attr_store,
3241 };
3242 static struct kobj_type rdev_ktype = {
3243 	.release	= rdev_free,
3244 	.sysfs_ops	= &rdev_sysfs_ops,
3245 	.default_attrs	= rdev_default_attrs,
3246 };
3247 
3248 int md_rdev_init(struct md_rdev *rdev)
3249 {
3250 	rdev->desc_nr = -1;
3251 	rdev->saved_raid_disk = -1;
3252 	rdev->raid_disk = -1;
3253 	rdev->flags = 0;
3254 	rdev->data_offset = 0;
3255 	rdev->new_data_offset = 0;
3256 	rdev->sb_events = 0;
3257 	rdev->last_read_error.tv_sec  = 0;
3258 	rdev->last_read_error.tv_nsec = 0;
3259 	rdev->sb_loaded = 0;
3260 	rdev->bb_page = NULL;
3261 	atomic_set(&rdev->nr_pending, 0);
3262 	atomic_set(&rdev->read_errors, 0);
3263 	atomic_set(&rdev->corrected_errors, 0);
3264 
3265 	INIT_LIST_HEAD(&rdev->same_set);
3266 	init_waitqueue_head(&rdev->blocked_wait);
3267 
3268 	/* Add space to store bad block list.
3269 	 * This reserves the space even on arrays where it cannot
3270 	 * be used - I wonder if that matters
3271 	 */
3272 	rdev->badblocks.count = 0;
3273 	rdev->badblocks.shift = 0;
3274 	rdev->badblocks.page = kmalloc(PAGE_SIZE, GFP_KERNEL);
3275 	seqlock_init(&rdev->badblocks.lock);
3276 	if (rdev->badblocks.page == NULL)
3277 		return -ENOMEM;
3278 
3279 	return 0;
3280 }
3281 EXPORT_SYMBOL_GPL(md_rdev_init);
3282 /*
3283  * Import a device. If 'super_format' >= 0, then sanity check the superblock
3284  *
3285  * mark the device faulty if:
3286  *
3287  *   - the device is nonexistent (zero size)
3288  *   - the device has no valid superblock
3289  *
3290  * a faulty rdev _never_ has rdev->sb set.
3291  */
3292 static struct md_rdev *md_import_device(dev_t newdev, int super_format, int super_minor)
3293 {
3294 	char b[BDEVNAME_SIZE];
3295 	int err;
3296 	struct md_rdev *rdev;
3297 	sector_t size;
3298 
3299 	rdev = kzalloc(sizeof(*rdev), GFP_KERNEL);
3300 	if (!rdev) {
3301 		printk(KERN_ERR "md: could not alloc mem for new device!\n");
3302 		return ERR_PTR(-ENOMEM);
3303 	}
3304 
3305 	err = md_rdev_init(rdev);
3306 	if (err)
3307 		goto abort_free;
3308 	err = alloc_disk_sb(rdev);
3309 	if (err)
3310 		goto abort_free;
3311 
3312 	err = lock_rdev(rdev, newdev, super_format == -2);
3313 	if (err)
3314 		goto abort_free;
3315 
3316 	kobject_init(&rdev->kobj, &rdev_ktype);
3317 
3318 	size = i_size_read(rdev->bdev->bd_inode) >> BLOCK_SIZE_BITS;
3319 	if (!size) {
3320 		printk(KERN_WARNING
3321 			"md: %s has zero or unknown size, marking faulty!\n",
3322 			bdevname(rdev->bdev,b));
3323 		err = -EINVAL;
3324 		goto abort_free;
3325 	}
3326 
3327 	if (super_format >= 0) {
3328 		err = super_types[super_format].
3329 			load_super(rdev, NULL, super_minor);
3330 		if (err == -EINVAL) {
3331 			printk(KERN_WARNING
3332 				"md: %s does not have a valid v%d.%d "
3333 			       "superblock, not importing!\n",
3334 				bdevname(rdev->bdev,b),
3335 			       super_format, super_minor);
3336 			goto abort_free;
3337 		}
3338 		if (err < 0) {
3339 			printk(KERN_WARNING
3340 				"md: could not read %s's sb, not importing!\n",
3341 				bdevname(rdev->bdev,b));
3342 			goto abort_free;
3343 		}
3344 	}
3345 	if (super_format == -1)
3346 		/* hot-add for 0.90, or non-persistent: so no badblocks */
3347 		rdev->badblocks.shift = -1;
3348 
3349 	return rdev;
3350 
3351 abort_free:
3352 	if (rdev->bdev)
3353 		unlock_rdev(rdev);
3354 	md_rdev_clear(rdev);
3355 	kfree(rdev);
3356 	return ERR_PTR(err);
3357 }
3358 
3359 /*
3360  * Check a full RAID array for plausibility
3361  */
3362 
3363 
3364 static void analyze_sbs(struct mddev * mddev)
3365 {
3366 	int i;
3367 	struct md_rdev *rdev, *freshest, *tmp;
3368 	char b[BDEVNAME_SIZE];
3369 
3370 	freshest = NULL;
3371 	rdev_for_each_safe(rdev, tmp, mddev)
3372 		switch (super_types[mddev->major_version].
3373 			load_super(rdev, freshest, mddev->minor_version)) {
3374 		case 1:
3375 			freshest = rdev;
3376 			break;
3377 		case 0:
3378 			break;
3379 		default:
3380 			printk( KERN_ERR \
3381 				"md: fatal superblock inconsistency in %s"
3382 				" -- removing from array\n",
3383 				bdevname(rdev->bdev,b));
3384 			kick_rdev_from_array(rdev);
3385 		}
3386 
3387 
3388 	super_types[mddev->major_version].
3389 		validate_super(mddev, freshest);
3390 
3391 	i = 0;
3392 	rdev_for_each_safe(rdev, tmp, mddev) {
3393 		if (mddev->max_disks &&
3394 		    (rdev->desc_nr >= mddev->max_disks ||
3395 		     i > mddev->max_disks)) {
3396 			printk(KERN_WARNING
3397 			       "md: %s: %s: only %d devices permitted\n",
3398 			       mdname(mddev), bdevname(rdev->bdev, b),
3399 			       mddev->max_disks);
3400 			kick_rdev_from_array(rdev);
3401 			continue;
3402 		}
3403 		if (rdev != freshest)
3404 			if (super_types[mddev->major_version].
3405 			    validate_super(mddev, rdev)) {
3406 				printk(KERN_WARNING "md: kicking non-fresh %s"
3407 					" from array!\n",
3408 					bdevname(rdev->bdev,b));
3409 				kick_rdev_from_array(rdev);
3410 				continue;
3411 			}
3412 		if (mddev->level == LEVEL_MULTIPATH) {
3413 			rdev->desc_nr = i++;
3414 			rdev->raid_disk = rdev->desc_nr;
3415 			set_bit(In_sync, &rdev->flags);
3416 		} else if (rdev->raid_disk >= (mddev->raid_disks - min(0, mddev->delta_disks))) {
3417 			rdev->raid_disk = -1;
3418 			clear_bit(In_sync, &rdev->flags);
3419 		}
3420 	}
3421 }
3422 
3423 /* Read a fixed-point number.
3424  * Numbers in sysfs attributes should be in "standard" units where
3425  * possible, so time should be in seconds.
3426  * However we internally use a a much smaller unit such as
3427  * milliseconds or jiffies.
3428  * This function takes a decimal number with a possible fractional
3429  * component, and produces an integer which is the result of
3430  * multiplying that number by 10^'scale'.
3431  * all without any floating-point arithmetic.
3432  */
3433 int strict_strtoul_scaled(const char *cp, unsigned long *res, int scale)
3434 {
3435 	unsigned long result = 0;
3436 	long decimals = -1;
3437 	while (isdigit(*cp) || (*cp == '.' && decimals < 0)) {
3438 		if (*cp == '.')
3439 			decimals = 0;
3440 		else if (decimals < scale) {
3441 			unsigned int value;
3442 			value = *cp - '0';
3443 			result = result * 10 + value;
3444 			if (decimals >= 0)
3445 				decimals++;
3446 		}
3447 		cp++;
3448 	}
3449 	if (*cp == '\n')
3450 		cp++;
3451 	if (*cp)
3452 		return -EINVAL;
3453 	if (decimals < 0)
3454 		decimals = 0;
3455 	while (decimals < scale) {
3456 		result *= 10;
3457 		decimals ++;
3458 	}
3459 	*res = result;
3460 	return 0;
3461 }
3462 
3463 
3464 static void md_safemode_timeout(unsigned long data);
3465 
3466 static ssize_t
3467 safe_delay_show(struct mddev *mddev, char *page)
3468 {
3469 	int msec = (mddev->safemode_delay*1000)/HZ;
3470 	return sprintf(page, "%d.%03d\n", msec/1000, msec%1000);
3471 }
3472 static ssize_t
3473 safe_delay_store(struct mddev *mddev, const char *cbuf, size_t len)
3474 {
3475 	unsigned long msec;
3476 
3477 	if (strict_strtoul_scaled(cbuf, &msec, 3) < 0)
3478 		return -EINVAL;
3479 	if (msec == 0)
3480 		mddev->safemode_delay = 0;
3481 	else {
3482 		unsigned long old_delay = mddev->safemode_delay;
3483 		mddev->safemode_delay = (msec*HZ)/1000;
3484 		if (mddev->safemode_delay == 0)
3485 			mddev->safemode_delay = 1;
3486 		if (mddev->safemode_delay < old_delay)
3487 			md_safemode_timeout((unsigned long)mddev);
3488 	}
3489 	return len;
3490 }
3491 static struct md_sysfs_entry md_safe_delay =
3492 __ATTR(safe_mode_delay, S_IRUGO|S_IWUSR,safe_delay_show, safe_delay_store);
3493 
3494 static ssize_t
3495 level_show(struct mddev *mddev, char *page)
3496 {
3497 	struct md_personality *p = mddev->pers;
3498 	if (p)
3499 		return sprintf(page, "%s\n", p->name);
3500 	else if (mddev->clevel[0])
3501 		return sprintf(page, "%s\n", mddev->clevel);
3502 	else if (mddev->level != LEVEL_NONE)
3503 		return sprintf(page, "%d\n", mddev->level);
3504 	else
3505 		return 0;
3506 }
3507 
3508 static ssize_t
3509 level_store(struct mddev *mddev, const char *buf, size_t len)
3510 {
3511 	char clevel[16];
3512 	ssize_t rv = len;
3513 	struct md_personality *pers;
3514 	long level;
3515 	void *priv;
3516 	struct md_rdev *rdev;
3517 
3518 	if (mddev->pers == NULL) {
3519 		if (len == 0)
3520 			return 0;
3521 		if (len >= sizeof(mddev->clevel))
3522 			return -ENOSPC;
3523 		strncpy(mddev->clevel, buf, len);
3524 		if (mddev->clevel[len-1] == '\n')
3525 			len--;
3526 		mddev->clevel[len] = 0;
3527 		mddev->level = LEVEL_NONE;
3528 		return rv;
3529 	}
3530 
3531 	/* request to change the personality.  Need to ensure:
3532 	 *  - array is not engaged in resync/recovery/reshape
3533 	 *  - old personality can be suspended
3534 	 *  - new personality will access other array.
3535 	 */
3536 
3537 	if (mddev->sync_thread ||
3538 	    mddev->reshape_position != MaxSector ||
3539 	    mddev->sysfs_active)
3540 		return -EBUSY;
3541 
3542 	if (!mddev->pers->quiesce) {
3543 		printk(KERN_WARNING "md: %s: %s does not support online personality change\n",
3544 		       mdname(mddev), mddev->pers->name);
3545 		return -EINVAL;
3546 	}
3547 
3548 	/* Now find the new personality */
3549 	if (len == 0 || len >= sizeof(clevel))
3550 		return -EINVAL;
3551 	strncpy(clevel, buf, len);
3552 	if (clevel[len-1] == '\n')
3553 		len--;
3554 	clevel[len] = 0;
3555 	if (strict_strtol(clevel, 10, &level))
3556 		level = LEVEL_NONE;
3557 
3558 	if (request_module("md-%s", clevel) != 0)
3559 		request_module("md-level-%s", clevel);
3560 	spin_lock(&pers_lock);
3561 	pers = find_pers(level, clevel);
3562 	if (!pers || !try_module_get(pers->owner)) {
3563 		spin_unlock(&pers_lock);
3564 		printk(KERN_WARNING "md: personality %s not loaded\n", clevel);
3565 		return -EINVAL;
3566 	}
3567 	spin_unlock(&pers_lock);
3568 
3569 	if (pers == mddev->pers) {
3570 		/* Nothing to do! */
3571 		module_put(pers->owner);
3572 		return rv;
3573 	}
3574 	if (!pers->takeover) {
3575 		module_put(pers->owner);
3576 		printk(KERN_WARNING "md: %s: %s does not support personality takeover\n",
3577 		       mdname(mddev), clevel);
3578 		return -EINVAL;
3579 	}
3580 
3581 	rdev_for_each(rdev, mddev)
3582 		rdev->new_raid_disk = rdev->raid_disk;
3583 
3584 	/* ->takeover must set new_* and/or delta_disks
3585 	 * if it succeeds, and may set them when it fails.
3586 	 */
3587 	priv = pers->takeover(mddev);
3588 	if (IS_ERR(priv)) {
3589 		mddev->new_level = mddev->level;
3590 		mddev->new_layout = mddev->layout;
3591 		mddev->new_chunk_sectors = mddev->chunk_sectors;
3592 		mddev->raid_disks -= mddev->delta_disks;
3593 		mddev->delta_disks = 0;
3594 		mddev->reshape_backwards = 0;
3595 		module_put(pers->owner);
3596 		printk(KERN_WARNING "md: %s: %s would not accept array\n",
3597 		       mdname(mddev), clevel);
3598 		return PTR_ERR(priv);
3599 	}
3600 
3601 	/* Looks like we have a winner */
3602 	mddev_suspend(mddev);
3603 	mddev->pers->stop(mddev);
3604 
3605 	if (mddev->pers->sync_request == NULL &&
3606 	    pers->sync_request != NULL) {
3607 		/* need to add the md_redundancy_group */
3608 		if (sysfs_create_group(&mddev->kobj, &md_redundancy_group))
3609 			printk(KERN_WARNING
3610 			       "md: cannot register extra attributes for %s\n",
3611 			       mdname(mddev));
3612 		mddev->sysfs_action = sysfs_get_dirent(mddev->kobj.sd, NULL, "sync_action");
3613 	}
3614 	if (mddev->pers->sync_request != NULL &&
3615 	    pers->sync_request == NULL) {
3616 		/* need to remove the md_redundancy_group */
3617 		if (mddev->to_remove == NULL)
3618 			mddev->to_remove = &md_redundancy_group;
3619 	}
3620 
3621 	if (mddev->pers->sync_request == NULL &&
3622 	    mddev->external) {
3623 		/* We are converting from a no-redundancy array
3624 		 * to a redundancy array and metadata is managed
3625 		 * externally so we need to be sure that writes
3626 		 * won't block due to a need to transition
3627 		 *      clean->dirty
3628 		 * until external management is started.
3629 		 */
3630 		mddev->in_sync = 0;
3631 		mddev->safemode_delay = 0;
3632 		mddev->safemode = 0;
3633 	}
3634 
3635 	rdev_for_each(rdev, mddev) {
3636 		if (rdev->raid_disk < 0)
3637 			continue;
3638 		if (rdev->new_raid_disk >= mddev->raid_disks)
3639 			rdev->new_raid_disk = -1;
3640 		if (rdev->new_raid_disk == rdev->raid_disk)
3641 			continue;
3642 		sysfs_unlink_rdev(mddev, rdev);
3643 	}
3644 	rdev_for_each(rdev, mddev) {
3645 		if (rdev->raid_disk < 0)
3646 			continue;
3647 		if (rdev->new_raid_disk == rdev->raid_disk)
3648 			continue;
3649 		rdev->raid_disk = rdev->new_raid_disk;
3650 		if (rdev->raid_disk < 0)
3651 			clear_bit(In_sync, &rdev->flags);
3652 		else {
3653 			if (sysfs_link_rdev(mddev, rdev))
3654 				printk(KERN_WARNING "md: cannot register rd%d"
3655 				       " for %s after level change\n",
3656 				       rdev->raid_disk, mdname(mddev));
3657 		}
3658 	}
3659 
3660 	module_put(mddev->pers->owner);
3661 	mddev->pers = pers;
3662 	mddev->private = priv;
3663 	strlcpy(mddev->clevel, pers->name, sizeof(mddev->clevel));
3664 	mddev->level = mddev->new_level;
3665 	mddev->layout = mddev->new_layout;
3666 	mddev->chunk_sectors = mddev->new_chunk_sectors;
3667 	mddev->delta_disks = 0;
3668 	mddev->reshape_backwards = 0;
3669 	mddev->degraded = 0;
3670 	if (mddev->pers->sync_request == NULL) {
3671 		/* this is now an array without redundancy, so
3672 		 * it must always be in_sync
3673 		 */
3674 		mddev->in_sync = 1;
3675 		del_timer_sync(&mddev->safemode_timer);
3676 	}
3677 	pers->run(mddev);
3678 	set_bit(MD_CHANGE_DEVS, &mddev->flags);
3679 	mddev_resume(mddev);
3680 	sysfs_notify(&mddev->kobj, NULL, "level");
3681 	md_new_event(mddev);
3682 	return rv;
3683 }
3684 
3685 static struct md_sysfs_entry md_level =
3686 __ATTR(level, S_IRUGO|S_IWUSR, level_show, level_store);
3687 
3688 
3689 static ssize_t
3690 layout_show(struct mddev *mddev, char *page)
3691 {
3692 	/* just a number, not meaningful for all levels */
3693 	if (mddev->reshape_position != MaxSector &&
3694 	    mddev->layout != mddev->new_layout)
3695 		return sprintf(page, "%d (%d)\n",
3696 			       mddev->new_layout, mddev->layout);
3697 	return sprintf(page, "%d\n", mddev->layout);
3698 }
3699 
3700 static ssize_t
3701 layout_store(struct mddev *mddev, const char *buf, size_t len)
3702 {
3703 	char *e;
3704 	unsigned long n = simple_strtoul(buf, &e, 10);
3705 
3706 	if (!*buf || (*e && *e != '\n'))
3707 		return -EINVAL;
3708 
3709 	if (mddev->pers) {
3710 		int err;
3711 		if (mddev->pers->check_reshape == NULL)
3712 			return -EBUSY;
3713 		mddev->new_layout = n;
3714 		err = mddev->pers->check_reshape(mddev);
3715 		if (err) {
3716 			mddev->new_layout = mddev->layout;
3717 			return err;
3718 		}
3719 	} else {
3720 		mddev->new_layout = n;
3721 		if (mddev->reshape_position == MaxSector)
3722 			mddev->layout = n;
3723 	}
3724 	return len;
3725 }
3726 static struct md_sysfs_entry md_layout =
3727 __ATTR(layout, S_IRUGO|S_IWUSR, layout_show, layout_store);
3728 
3729 
3730 static ssize_t
3731 raid_disks_show(struct mddev *mddev, char *page)
3732 {
3733 	if (mddev->raid_disks == 0)
3734 		return 0;
3735 	if (mddev->reshape_position != MaxSector &&
3736 	    mddev->delta_disks != 0)
3737 		return sprintf(page, "%d (%d)\n", mddev->raid_disks,
3738 			       mddev->raid_disks - mddev->delta_disks);
3739 	return sprintf(page, "%d\n", mddev->raid_disks);
3740 }
3741 
3742 static int update_raid_disks(struct mddev *mddev, int raid_disks);
3743 
3744 static ssize_t
3745 raid_disks_store(struct mddev *mddev, const char *buf, size_t len)
3746 {
3747 	char *e;
3748 	int rv = 0;
3749 	unsigned long n = simple_strtoul(buf, &e, 10);
3750 
3751 	if (!*buf || (*e && *e != '\n'))
3752 		return -EINVAL;
3753 
3754 	if (mddev->pers)
3755 		rv = update_raid_disks(mddev, n);
3756 	else if (mddev->reshape_position != MaxSector) {
3757 		struct md_rdev *rdev;
3758 		int olddisks = mddev->raid_disks - mddev->delta_disks;
3759 
3760 		rdev_for_each(rdev, mddev) {
3761 			if (olddisks < n &&
3762 			    rdev->data_offset < rdev->new_data_offset)
3763 				return -EINVAL;
3764 			if (olddisks > n &&
3765 			    rdev->data_offset > rdev->new_data_offset)
3766 				return -EINVAL;
3767 		}
3768 		mddev->delta_disks = n - olddisks;
3769 		mddev->raid_disks = n;
3770 		mddev->reshape_backwards = (mddev->delta_disks < 0);
3771 	} else
3772 		mddev->raid_disks = n;
3773 	return rv ? rv : len;
3774 }
3775 static struct md_sysfs_entry md_raid_disks =
3776 __ATTR(raid_disks, S_IRUGO|S_IWUSR, raid_disks_show, raid_disks_store);
3777 
3778 static ssize_t
3779 chunk_size_show(struct mddev *mddev, char *page)
3780 {
3781 	if (mddev->reshape_position != MaxSector &&
3782 	    mddev->chunk_sectors != mddev->new_chunk_sectors)
3783 		return sprintf(page, "%d (%d)\n",
3784 			       mddev->new_chunk_sectors << 9,
3785 			       mddev->chunk_sectors << 9);
3786 	return sprintf(page, "%d\n", mddev->chunk_sectors << 9);
3787 }
3788 
3789 static ssize_t
3790 chunk_size_store(struct mddev *mddev, const char *buf, size_t len)
3791 {
3792 	char *e;
3793 	unsigned long n = simple_strtoul(buf, &e, 10);
3794 
3795 	if (!*buf || (*e && *e != '\n'))
3796 		return -EINVAL;
3797 
3798 	if (mddev->pers) {
3799 		int err;
3800 		if (mddev->pers->check_reshape == NULL)
3801 			return -EBUSY;
3802 		mddev->new_chunk_sectors = n >> 9;
3803 		err = mddev->pers->check_reshape(mddev);
3804 		if (err) {
3805 			mddev->new_chunk_sectors = mddev->chunk_sectors;
3806 			return err;
3807 		}
3808 	} else {
3809 		mddev->new_chunk_sectors = n >> 9;
3810 		if (mddev->reshape_position == MaxSector)
3811 			mddev->chunk_sectors = n >> 9;
3812 	}
3813 	return len;
3814 }
3815 static struct md_sysfs_entry md_chunk_size =
3816 __ATTR(chunk_size, S_IRUGO|S_IWUSR, chunk_size_show, chunk_size_store);
3817 
3818 static ssize_t
3819 resync_start_show(struct mddev *mddev, char *page)
3820 {
3821 	if (mddev->recovery_cp == MaxSector)
3822 		return sprintf(page, "none\n");
3823 	return sprintf(page, "%llu\n", (unsigned long long)mddev->recovery_cp);
3824 }
3825 
3826 static ssize_t
3827 resync_start_store(struct mddev *mddev, const char *buf, size_t len)
3828 {
3829 	char *e;
3830 	unsigned long long n = simple_strtoull(buf, &e, 10);
3831 
3832 	if (mddev->pers && !test_bit(MD_RECOVERY_FROZEN, &mddev->recovery))
3833 		return -EBUSY;
3834 	if (cmd_match(buf, "none"))
3835 		n = MaxSector;
3836 	else if (!*buf || (*e && *e != '\n'))
3837 		return -EINVAL;
3838 
3839 	mddev->recovery_cp = n;
3840 	return len;
3841 }
3842 static struct md_sysfs_entry md_resync_start =
3843 __ATTR(resync_start, S_IRUGO|S_IWUSR, resync_start_show, resync_start_store);
3844 
3845 /*
3846  * The array state can be:
3847  *
3848  * clear
3849  *     No devices, no size, no level
3850  *     Equivalent to STOP_ARRAY ioctl
3851  * inactive
3852  *     May have some settings, but array is not active
3853  *        all IO results in error
3854  *     When written, doesn't tear down array, but just stops it
3855  * suspended (not supported yet)
3856  *     All IO requests will block. The array can be reconfigured.
3857  *     Writing this, if accepted, will block until array is quiescent
3858  * readonly
3859  *     no resync can happen.  no superblocks get written.
3860  *     write requests fail
3861  * read-auto
3862  *     like readonly, but behaves like 'clean' on a write request.
3863  *
3864  * clean - no pending writes, but otherwise active.
3865  *     When written to inactive array, starts without resync
3866  *     If a write request arrives then
3867  *       if metadata is known, mark 'dirty' and switch to 'active'.
3868  *       if not known, block and switch to write-pending
3869  *     If written to an active array that has pending writes, then fails.
3870  * active
3871  *     fully active: IO and resync can be happening.
3872  *     When written to inactive array, starts with resync
3873  *
3874  * write-pending
3875  *     clean, but writes are blocked waiting for 'active' to be written.
3876  *
3877  * active-idle
3878  *     like active, but no writes have been seen for a while (100msec).
3879  *
3880  */
3881 enum array_state { clear, inactive, suspended, readonly, read_auto, clean, active,
3882 		   write_pending, active_idle, bad_word};
3883 static char *array_states[] = {
3884 	"clear", "inactive", "suspended", "readonly", "read-auto", "clean", "active",
3885 	"write-pending", "active-idle", NULL };
3886 
3887 static int match_word(const char *word, char **list)
3888 {
3889 	int n;
3890 	for (n=0; list[n]; n++)
3891 		if (cmd_match(word, list[n]))
3892 			break;
3893 	return n;
3894 }
3895 
3896 static ssize_t
3897 array_state_show(struct mddev *mddev, char *page)
3898 {
3899 	enum array_state st = inactive;
3900 
3901 	if (mddev->pers)
3902 		switch(mddev->ro) {
3903 		case 1:
3904 			st = readonly;
3905 			break;
3906 		case 2:
3907 			st = read_auto;
3908 			break;
3909 		case 0:
3910 			if (mddev->in_sync)
3911 				st = clean;
3912 			else if (test_bit(MD_CHANGE_PENDING, &mddev->flags))
3913 				st = write_pending;
3914 			else if (mddev->safemode)
3915 				st = active_idle;
3916 			else
3917 				st = active;
3918 		}
3919 	else {
3920 		if (list_empty(&mddev->disks) &&
3921 		    mddev->raid_disks == 0 &&
3922 		    mddev->dev_sectors == 0)
3923 			st = clear;
3924 		else
3925 			st = inactive;
3926 	}
3927 	return sprintf(page, "%s\n", array_states[st]);
3928 }
3929 
3930 static int do_md_stop(struct mddev * mddev, int ro, struct block_device *bdev);
3931 static int md_set_readonly(struct mddev * mddev, struct block_device *bdev);
3932 static int do_md_run(struct mddev * mddev);
3933 static int restart_array(struct mddev *mddev);
3934 
3935 static ssize_t
3936 array_state_store(struct mddev *mddev, const char *buf, size_t len)
3937 {
3938 	int err = -EINVAL;
3939 	enum array_state st = match_word(buf, array_states);
3940 	switch(st) {
3941 	case bad_word:
3942 		break;
3943 	case clear:
3944 		/* stopping an active array */
3945 		if (atomic_read(&mddev->openers) > 0)
3946 			return -EBUSY;
3947 		err = do_md_stop(mddev, 0, NULL);
3948 		break;
3949 	case inactive:
3950 		/* stopping an active array */
3951 		if (mddev->pers) {
3952 			if (atomic_read(&mddev->openers) > 0)
3953 				return -EBUSY;
3954 			err = do_md_stop(mddev, 2, NULL);
3955 		} else
3956 			err = 0; /* already inactive */
3957 		break;
3958 	case suspended:
3959 		break; /* not supported yet */
3960 	case readonly:
3961 		if (mddev->pers)
3962 			err = md_set_readonly(mddev, NULL);
3963 		else {
3964 			mddev->ro = 1;
3965 			set_disk_ro(mddev->gendisk, 1);
3966 			err = do_md_run(mddev);
3967 		}
3968 		break;
3969 	case read_auto:
3970 		if (mddev->pers) {
3971 			if (mddev->ro == 0)
3972 				err = md_set_readonly(mddev, NULL);
3973 			else if (mddev->ro == 1)
3974 				err = restart_array(mddev);
3975 			if (err == 0) {
3976 				mddev->ro = 2;
3977 				set_disk_ro(mddev->gendisk, 0);
3978 			}
3979 		} else {
3980 			mddev->ro = 2;
3981 			err = do_md_run(mddev);
3982 		}
3983 		break;
3984 	case clean:
3985 		if (mddev->pers) {
3986 			restart_array(mddev);
3987 			spin_lock_irq(&mddev->write_lock);
3988 			if (atomic_read(&mddev->writes_pending) == 0) {
3989 				if (mddev->in_sync == 0) {
3990 					mddev->in_sync = 1;
3991 					if (mddev->safemode == 1)
3992 						mddev->safemode = 0;
3993 					set_bit(MD_CHANGE_CLEAN, &mddev->flags);
3994 				}
3995 				err = 0;
3996 			} else
3997 				err = -EBUSY;
3998 			spin_unlock_irq(&mddev->write_lock);
3999 		} else
4000 			err = -EINVAL;
4001 		break;
4002 	case active:
4003 		if (mddev->pers) {
4004 			restart_array(mddev);
4005 			clear_bit(MD_CHANGE_PENDING, &mddev->flags);
4006 			wake_up(&mddev->sb_wait);
4007 			err = 0;
4008 		} else {
4009 			mddev->ro = 0;
4010 			set_disk_ro(mddev->gendisk, 0);
4011 			err = do_md_run(mddev);
4012 		}
4013 		break;
4014 	case write_pending:
4015 	case active_idle:
4016 		/* these cannot be set */
4017 		break;
4018 	}
4019 	if (err)
4020 		return err;
4021 	else {
4022 		if (mddev->hold_active == UNTIL_IOCTL)
4023 			mddev->hold_active = 0;
4024 		sysfs_notify_dirent_safe(mddev->sysfs_state);
4025 		return len;
4026 	}
4027 }
4028 static struct md_sysfs_entry md_array_state =
4029 __ATTR(array_state, S_IRUGO|S_IWUSR, array_state_show, array_state_store);
4030 
4031 static ssize_t
4032 max_corrected_read_errors_show(struct mddev *mddev, char *page) {
4033 	return sprintf(page, "%d\n",
4034 		       atomic_read(&mddev->max_corr_read_errors));
4035 }
4036 
4037 static ssize_t
4038 max_corrected_read_errors_store(struct mddev *mddev, const char *buf, size_t len)
4039 {
4040 	char *e;
4041 	unsigned long n = simple_strtoul(buf, &e, 10);
4042 
4043 	if (*buf && (*e == 0 || *e == '\n')) {
4044 		atomic_set(&mddev->max_corr_read_errors, n);
4045 		return len;
4046 	}
4047 	return -EINVAL;
4048 }
4049 
4050 static struct md_sysfs_entry max_corr_read_errors =
4051 __ATTR(max_read_errors, S_IRUGO|S_IWUSR, max_corrected_read_errors_show,
4052 	max_corrected_read_errors_store);
4053 
4054 static ssize_t
4055 null_show(struct mddev *mddev, char *page)
4056 {
4057 	return -EINVAL;
4058 }
4059 
4060 static ssize_t
4061 new_dev_store(struct mddev *mddev, const char *buf, size_t len)
4062 {
4063 	/* buf must be %d:%d\n? giving major and minor numbers */
4064 	/* The new device is added to the array.
4065 	 * If the array has a persistent superblock, we read the
4066 	 * superblock to initialise info and check validity.
4067 	 * Otherwise, only checking done is that in bind_rdev_to_array,
4068 	 * which mainly checks size.
4069 	 */
4070 	char *e;
4071 	int major = simple_strtoul(buf, &e, 10);
4072 	int minor;
4073 	dev_t dev;
4074 	struct md_rdev *rdev;
4075 	int err;
4076 
4077 	if (!*buf || *e != ':' || !e[1] || e[1] == '\n')
4078 		return -EINVAL;
4079 	minor = simple_strtoul(e+1, &e, 10);
4080 	if (*e && *e != '\n')
4081 		return -EINVAL;
4082 	dev = MKDEV(major, minor);
4083 	if (major != MAJOR(dev) ||
4084 	    minor != MINOR(dev))
4085 		return -EOVERFLOW;
4086 
4087 
4088 	if (mddev->persistent) {
4089 		rdev = md_import_device(dev, mddev->major_version,
4090 					mddev->minor_version);
4091 		if (!IS_ERR(rdev) && !list_empty(&mddev->disks)) {
4092 			struct md_rdev *rdev0
4093 				= list_entry(mddev->disks.next,
4094 					     struct md_rdev, same_set);
4095 			err = super_types[mddev->major_version]
4096 				.load_super(rdev, rdev0, mddev->minor_version);
4097 			if (err < 0)
4098 				goto out;
4099 		}
4100 	} else if (mddev->external)
4101 		rdev = md_import_device(dev, -2, -1);
4102 	else
4103 		rdev = md_import_device(dev, -1, -1);
4104 
4105 	if (IS_ERR(rdev))
4106 		return PTR_ERR(rdev);
4107 	err = bind_rdev_to_array(rdev, mddev);
4108  out:
4109 	if (err)
4110 		export_rdev(rdev);
4111 	return err ? err : len;
4112 }
4113 
4114 static struct md_sysfs_entry md_new_device =
4115 __ATTR(new_dev, S_IWUSR, null_show, new_dev_store);
4116 
4117 static ssize_t
4118 bitmap_store(struct mddev *mddev, const char *buf, size_t len)
4119 {
4120 	char *end;
4121 	unsigned long chunk, end_chunk;
4122 
4123 	if (!mddev->bitmap)
4124 		goto out;
4125 	/* buf should be <chunk> <chunk> ... or <chunk>-<chunk> ... (range) */
4126 	while (*buf) {
4127 		chunk = end_chunk = simple_strtoul(buf, &end, 0);
4128 		if (buf == end) break;
4129 		if (*end == '-') { /* range */
4130 			buf = end + 1;
4131 			end_chunk = simple_strtoul(buf, &end, 0);
4132 			if (buf == end) break;
4133 		}
4134 		if (*end && !isspace(*end)) break;
4135 		bitmap_dirty_bits(mddev->bitmap, chunk, end_chunk);
4136 		buf = skip_spaces(end);
4137 	}
4138 	bitmap_unplug(mddev->bitmap); /* flush the bits to disk */
4139 out:
4140 	return len;
4141 }
4142 
4143 static struct md_sysfs_entry md_bitmap =
4144 __ATTR(bitmap_set_bits, S_IWUSR, null_show, bitmap_store);
4145 
4146 static ssize_t
4147 size_show(struct mddev *mddev, char *page)
4148 {
4149 	return sprintf(page, "%llu\n",
4150 		(unsigned long long)mddev->dev_sectors / 2);
4151 }
4152 
4153 static int update_size(struct mddev *mddev, sector_t num_sectors);
4154 
4155 static ssize_t
4156 size_store(struct mddev *mddev, const char *buf, size_t len)
4157 {
4158 	/* If array is inactive, we can reduce the component size, but
4159 	 * not increase it (except from 0).
4160 	 * If array is active, we can try an on-line resize
4161 	 */
4162 	sector_t sectors;
4163 	int err = strict_blocks_to_sectors(buf, &sectors);
4164 
4165 	if (err < 0)
4166 		return err;
4167 	if (mddev->pers) {
4168 		err = update_size(mddev, sectors);
4169 		md_update_sb(mddev, 1);
4170 	} else {
4171 		if (mddev->dev_sectors == 0 ||
4172 		    mddev->dev_sectors > sectors)
4173 			mddev->dev_sectors = sectors;
4174 		else
4175 			err = -ENOSPC;
4176 	}
4177 	return err ? err : len;
4178 }
4179 
4180 static struct md_sysfs_entry md_size =
4181 __ATTR(component_size, S_IRUGO|S_IWUSR, size_show, size_store);
4182 
4183 
4184 /* Metdata version.
4185  * This is one of
4186  *   'none' for arrays with no metadata (good luck...)
4187  *   'external' for arrays with externally managed metadata,
4188  * or N.M for internally known formats
4189  */
4190 static ssize_t
4191 metadata_show(struct mddev *mddev, char *page)
4192 {
4193 	if (mddev->persistent)
4194 		return sprintf(page, "%d.%d\n",
4195 			       mddev->major_version, mddev->minor_version);
4196 	else if (mddev->external)
4197 		return sprintf(page, "external:%s\n", mddev->metadata_type);
4198 	else
4199 		return sprintf(page, "none\n");
4200 }
4201 
4202 static ssize_t
4203 metadata_store(struct mddev *mddev, const char *buf, size_t len)
4204 {
4205 	int major, minor;
4206 	char *e;
4207 	/* Changing the details of 'external' metadata is
4208 	 * always permitted.  Otherwise there must be
4209 	 * no devices attached to the array.
4210 	 */
4211 	if (mddev->external && strncmp(buf, "external:", 9) == 0)
4212 		;
4213 	else if (!list_empty(&mddev->disks))
4214 		return -EBUSY;
4215 
4216 	if (cmd_match(buf, "none")) {
4217 		mddev->persistent = 0;
4218 		mddev->external = 0;
4219 		mddev->major_version = 0;
4220 		mddev->minor_version = 90;
4221 		return len;
4222 	}
4223 	if (strncmp(buf, "external:", 9) == 0) {
4224 		size_t namelen = len-9;
4225 		if (namelen >= sizeof(mddev->metadata_type))
4226 			namelen = sizeof(mddev->metadata_type)-1;
4227 		strncpy(mddev->metadata_type, buf+9, namelen);
4228 		mddev->metadata_type[namelen] = 0;
4229 		if (namelen && mddev->metadata_type[namelen-1] == '\n')
4230 			mddev->metadata_type[--namelen] = 0;
4231 		mddev->persistent = 0;
4232 		mddev->external = 1;
4233 		mddev->major_version = 0;
4234 		mddev->minor_version = 90;
4235 		return len;
4236 	}
4237 	major = simple_strtoul(buf, &e, 10);
4238 	if (e==buf || *e != '.')
4239 		return -EINVAL;
4240 	buf = e+1;
4241 	minor = simple_strtoul(buf, &e, 10);
4242 	if (e==buf || (*e && *e != '\n') )
4243 		return -EINVAL;
4244 	if (major >= ARRAY_SIZE(super_types) || super_types[major].name == NULL)
4245 		return -ENOENT;
4246 	mddev->major_version = major;
4247 	mddev->minor_version = minor;
4248 	mddev->persistent = 1;
4249 	mddev->external = 0;
4250 	return len;
4251 }
4252 
4253 static struct md_sysfs_entry md_metadata =
4254 __ATTR(metadata_version, S_IRUGO|S_IWUSR, metadata_show, metadata_store);
4255 
4256 static ssize_t
4257 action_show(struct mddev *mddev, char *page)
4258 {
4259 	char *type = "idle";
4260 	if (test_bit(MD_RECOVERY_FROZEN, &mddev->recovery))
4261 		type = "frozen";
4262 	else if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
4263 	    (!mddev->ro && test_bit(MD_RECOVERY_NEEDED, &mddev->recovery))) {
4264 		if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
4265 			type = "reshape";
4266 		else if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
4267 			if (!test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
4268 				type = "resync";
4269 			else if (test_bit(MD_RECOVERY_CHECK, &mddev->recovery))
4270 				type = "check";
4271 			else
4272 				type = "repair";
4273 		} else if (test_bit(MD_RECOVERY_RECOVER, &mddev->recovery))
4274 			type = "recover";
4275 	}
4276 	return sprintf(page, "%s\n", type);
4277 }
4278 
4279 static void reap_sync_thread(struct mddev *mddev);
4280 
4281 static ssize_t
4282 action_store(struct mddev *mddev, const char *page, size_t len)
4283 {
4284 	if (!mddev->pers || !mddev->pers->sync_request)
4285 		return -EINVAL;
4286 
4287 	if (cmd_match(page, "frozen"))
4288 		set_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
4289 	else
4290 		clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
4291 
4292 	if (cmd_match(page, "idle") || cmd_match(page, "frozen")) {
4293 		if (mddev->sync_thread) {
4294 			set_bit(MD_RECOVERY_INTR, &mddev->recovery);
4295 			reap_sync_thread(mddev);
4296 		}
4297 	} else if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
4298 		   test_bit(MD_RECOVERY_NEEDED, &mddev->recovery))
4299 		return -EBUSY;
4300 	else if (cmd_match(page, "resync"))
4301 		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
4302 	else if (cmd_match(page, "recover")) {
4303 		set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
4304 		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
4305 	} else if (cmd_match(page, "reshape")) {
4306 		int err;
4307 		if (mddev->pers->start_reshape == NULL)
4308 			return -EINVAL;
4309 		err = mddev->pers->start_reshape(mddev);
4310 		if (err)
4311 			return err;
4312 		sysfs_notify(&mddev->kobj, NULL, "degraded");
4313 	} else {
4314 		if (cmd_match(page, "check"))
4315 			set_bit(MD_RECOVERY_CHECK, &mddev->recovery);
4316 		else if (!cmd_match(page, "repair"))
4317 			return -EINVAL;
4318 		set_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
4319 		set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
4320 	}
4321 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
4322 	md_wakeup_thread(mddev->thread);
4323 	sysfs_notify_dirent_safe(mddev->sysfs_action);
4324 	return len;
4325 }
4326 
4327 static ssize_t
4328 mismatch_cnt_show(struct mddev *mddev, char *page)
4329 {
4330 	return sprintf(page, "%llu\n",
4331 		       (unsigned long long) mddev->resync_mismatches);
4332 }
4333 
4334 static struct md_sysfs_entry md_scan_mode =
4335 __ATTR(sync_action, S_IRUGO|S_IWUSR, action_show, action_store);
4336 
4337 
4338 static struct md_sysfs_entry md_mismatches = __ATTR_RO(mismatch_cnt);
4339 
4340 static ssize_t
4341 sync_min_show(struct mddev *mddev, char *page)
4342 {
4343 	return sprintf(page, "%d (%s)\n", speed_min(mddev),
4344 		       mddev->sync_speed_min ? "local": "system");
4345 }
4346 
4347 static ssize_t
4348 sync_min_store(struct mddev *mddev, const char *buf, size_t len)
4349 {
4350 	int min;
4351 	char *e;
4352 	if (strncmp(buf, "system", 6)==0) {
4353 		mddev->sync_speed_min = 0;
4354 		return len;
4355 	}
4356 	min = simple_strtoul(buf, &e, 10);
4357 	if (buf == e || (*e && *e != '\n') || min <= 0)
4358 		return -EINVAL;
4359 	mddev->sync_speed_min = min;
4360 	return len;
4361 }
4362 
4363 static struct md_sysfs_entry md_sync_min =
4364 __ATTR(sync_speed_min, S_IRUGO|S_IWUSR, sync_min_show, sync_min_store);
4365 
4366 static ssize_t
4367 sync_max_show(struct mddev *mddev, char *page)
4368 {
4369 	return sprintf(page, "%d (%s)\n", speed_max(mddev),
4370 		       mddev->sync_speed_max ? "local": "system");
4371 }
4372 
4373 static ssize_t
4374 sync_max_store(struct mddev *mddev, const char *buf, size_t len)
4375 {
4376 	int max;
4377 	char *e;
4378 	if (strncmp(buf, "system", 6)==0) {
4379 		mddev->sync_speed_max = 0;
4380 		return len;
4381 	}
4382 	max = simple_strtoul(buf, &e, 10);
4383 	if (buf == e || (*e && *e != '\n') || max <= 0)
4384 		return -EINVAL;
4385 	mddev->sync_speed_max = max;
4386 	return len;
4387 }
4388 
4389 static struct md_sysfs_entry md_sync_max =
4390 __ATTR(sync_speed_max, S_IRUGO|S_IWUSR, sync_max_show, sync_max_store);
4391 
4392 static ssize_t
4393 degraded_show(struct mddev *mddev, char *page)
4394 {
4395 	return sprintf(page, "%d\n", mddev->degraded);
4396 }
4397 static struct md_sysfs_entry md_degraded = __ATTR_RO(degraded);
4398 
4399 static ssize_t
4400 sync_force_parallel_show(struct mddev *mddev, char *page)
4401 {
4402 	return sprintf(page, "%d\n", mddev->parallel_resync);
4403 }
4404 
4405 static ssize_t
4406 sync_force_parallel_store(struct mddev *mddev, const char *buf, size_t len)
4407 {
4408 	long n;
4409 
4410 	if (strict_strtol(buf, 10, &n))
4411 		return -EINVAL;
4412 
4413 	if (n != 0 && n != 1)
4414 		return -EINVAL;
4415 
4416 	mddev->parallel_resync = n;
4417 
4418 	if (mddev->sync_thread)
4419 		wake_up(&resync_wait);
4420 
4421 	return len;
4422 }
4423 
4424 /* force parallel resync, even with shared block devices */
4425 static struct md_sysfs_entry md_sync_force_parallel =
4426 __ATTR(sync_force_parallel, S_IRUGO|S_IWUSR,
4427        sync_force_parallel_show, sync_force_parallel_store);
4428 
4429 static ssize_t
4430 sync_speed_show(struct mddev *mddev, char *page)
4431 {
4432 	unsigned long resync, dt, db;
4433 	if (mddev->curr_resync == 0)
4434 		return sprintf(page, "none\n");
4435 	resync = mddev->curr_mark_cnt - atomic_read(&mddev->recovery_active);
4436 	dt = (jiffies - mddev->resync_mark) / HZ;
4437 	if (!dt) dt++;
4438 	db = resync - mddev->resync_mark_cnt;
4439 	return sprintf(page, "%lu\n", db/dt/2); /* K/sec */
4440 }
4441 
4442 static struct md_sysfs_entry md_sync_speed = __ATTR_RO(sync_speed);
4443 
4444 static ssize_t
4445 sync_completed_show(struct mddev *mddev, char *page)
4446 {
4447 	unsigned long long max_sectors, resync;
4448 
4449 	if (!test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
4450 		return sprintf(page, "none\n");
4451 
4452 	if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) ||
4453 	    test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
4454 		max_sectors = mddev->resync_max_sectors;
4455 	else
4456 		max_sectors = mddev->dev_sectors;
4457 
4458 	resync = mddev->curr_resync_completed;
4459 	return sprintf(page, "%llu / %llu\n", resync, max_sectors);
4460 }
4461 
4462 static struct md_sysfs_entry md_sync_completed = __ATTR_RO(sync_completed);
4463 
4464 static ssize_t
4465 min_sync_show(struct mddev *mddev, char *page)
4466 {
4467 	return sprintf(page, "%llu\n",
4468 		       (unsigned long long)mddev->resync_min);
4469 }
4470 static ssize_t
4471 min_sync_store(struct mddev *mddev, const char *buf, size_t len)
4472 {
4473 	unsigned long long min;
4474 	if (strict_strtoull(buf, 10, &min))
4475 		return -EINVAL;
4476 	if (min > mddev->resync_max)
4477 		return -EINVAL;
4478 	if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
4479 		return -EBUSY;
4480 
4481 	/* Must be a multiple of chunk_size */
4482 	if (mddev->chunk_sectors) {
4483 		sector_t temp = min;
4484 		if (sector_div(temp, mddev->chunk_sectors))
4485 			return -EINVAL;
4486 	}
4487 	mddev->resync_min = min;
4488 
4489 	return len;
4490 }
4491 
4492 static struct md_sysfs_entry md_min_sync =
4493 __ATTR(sync_min, S_IRUGO|S_IWUSR, min_sync_show, min_sync_store);
4494 
4495 static ssize_t
4496 max_sync_show(struct mddev *mddev, char *page)
4497 {
4498 	if (mddev->resync_max == MaxSector)
4499 		return sprintf(page, "max\n");
4500 	else
4501 		return sprintf(page, "%llu\n",
4502 			       (unsigned long long)mddev->resync_max);
4503 }
4504 static ssize_t
4505 max_sync_store(struct mddev *mddev, const char *buf, size_t len)
4506 {
4507 	if (strncmp(buf, "max", 3) == 0)
4508 		mddev->resync_max = MaxSector;
4509 	else {
4510 		unsigned long long max;
4511 		if (strict_strtoull(buf, 10, &max))
4512 			return -EINVAL;
4513 		if (max < mddev->resync_min)
4514 			return -EINVAL;
4515 		if (max < mddev->resync_max &&
4516 		    mddev->ro == 0 &&
4517 		    test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
4518 			return -EBUSY;
4519 
4520 		/* Must be a multiple of chunk_size */
4521 		if (mddev->chunk_sectors) {
4522 			sector_t temp = max;
4523 			if (sector_div(temp, mddev->chunk_sectors))
4524 				return -EINVAL;
4525 		}
4526 		mddev->resync_max = max;
4527 	}
4528 	wake_up(&mddev->recovery_wait);
4529 	return len;
4530 }
4531 
4532 static struct md_sysfs_entry md_max_sync =
4533 __ATTR(sync_max, S_IRUGO|S_IWUSR, max_sync_show, max_sync_store);
4534 
4535 static ssize_t
4536 suspend_lo_show(struct mddev *mddev, char *page)
4537 {
4538 	return sprintf(page, "%llu\n", (unsigned long long)mddev->suspend_lo);
4539 }
4540 
4541 static ssize_t
4542 suspend_lo_store(struct mddev *mddev, const char *buf, size_t len)
4543 {
4544 	char *e;
4545 	unsigned long long new = simple_strtoull(buf, &e, 10);
4546 	unsigned long long old = mddev->suspend_lo;
4547 
4548 	if (mddev->pers == NULL ||
4549 	    mddev->pers->quiesce == NULL)
4550 		return -EINVAL;
4551 	if (buf == e || (*e && *e != '\n'))
4552 		return -EINVAL;
4553 
4554 	mddev->suspend_lo = new;
4555 	if (new >= old)
4556 		/* Shrinking suspended region */
4557 		mddev->pers->quiesce(mddev, 2);
4558 	else {
4559 		/* Expanding suspended region - need to wait */
4560 		mddev->pers->quiesce(mddev, 1);
4561 		mddev->pers->quiesce(mddev, 0);
4562 	}
4563 	return len;
4564 }
4565 static struct md_sysfs_entry md_suspend_lo =
4566 __ATTR(suspend_lo, S_IRUGO|S_IWUSR, suspend_lo_show, suspend_lo_store);
4567 
4568 
4569 static ssize_t
4570 suspend_hi_show(struct mddev *mddev, char *page)
4571 {
4572 	return sprintf(page, "%llu\n", (unsigned long long)mddev->suspend_hi);
4573 }
4574 
4575 static ssize_t
4576 suspend_hi_store(struct mddev *mddev, const char *buf, size_t len)
4577 {
4578 	char *e;
4579 	unsigned long long new = simple_strtoull(buf, &e, 10);
4580 	unsigned long long old = mddev->suspend_hi;
4581 
4582 	if (mddev->pers == NULL ||
4583 	    mddev->pers->quiesce == NULL)
4584 		return -EINVAL;
4585 	if (buf == e || (*e && *e != '\n'))
4586 		return -EINVAL;
4587 
4588 	mddev->suspend_hi = new;
4589 	if (new <= old)
4590 		/* Shrinking suspended region */
4591 		mddev->pers->quiesce(mddev, 2);
4592 	else {
4593 		/* Expanding suspended region - need to wait */
4594 		mddev->pers->quiesce(mddev, 1);
4595 		mddev->pers->quiesce(mddev, 0);
4596 	}
4597 	return len;
4598 }
4599 static struct md_sysfs_entry md_suspend_hi =
4600 __ATTR(suspend_hi, S_IRUGO|S_IWUSR, suspend_hi_show, suspend_hi_store);
4601 
4602 static ssize_t
4603 reshape_position_show(struct mddev *mddev, char *page)
4604 {
4605 	if (mddev->reshape_position != MaxSector)
4606 		return sprintf(page, "%llu\n",
4607 			       (unsigned long long)mddev->reshape_position);
4608 	strcpy(page, "none\n");
4609 	return 5;
4610 }
4611 
4612 static ssize_t
4613 reshape_position_store(struct mddev *mddev, const char *buf, size_t len)
4614 {
4615 	struct md_rdev *rdev;
4616 	char *e;
4617 	unsigned long long new = simple_strtoull(buf, &e, 10);
4618 	if (mddev->pers)
4619 		return -EBUSY;
4620 	if (buf == e || (*e && *e != '\n'))
4621 		return -EINVAL;
4622 	mddev->reshape_position = new;
4623 	mddev->delta_disks = 0;
4624 	mddev->reshape_backwards = 0;
4625 	mddev->new_level = mddev->level;
4626 	mddev->new_layout = mddev->layout;
4627 	mddev->new_chunk_sectors = mddev->chunk_sectors;
4628 	rdev_for_each(rdev, mddev)
4629 		rdev->new_data_offset = rdev->data_offset;
4630 	return len;
4631 }
4632 
4633 static struct md_sysfs_entry md_reshape_position =
4634 __ATTR(reshape_position, S_IRUGO|S_IWUSR, reshape_position_show,
4635        reshape_position_store);
4636 
4637 static ssize_t
4638 reshape_direction_show(struct mddev *mddev, char *page)
4639 {
4640 	return sprintf(page, "%s\n",
4641 		       mddev->reshape_backwards ? "backwards" : "forwards");
4642 }
4643 
4644 static ssize_t
4645 reshape_direction_store(struct mddev *mddev, const char *buf, size_t len)
4646 {
4647 	int backwards = 0;
4648 	if (cmd_match(buf, "forwards"))
4649 		backwards = 0;
4650 	else if (cmd_match(buf, "backwards"))
4651 		backwards = 1;
4652 	else
4653 		return -EINVAL;
4654 	if (mddev->reshape_backwards == backwards)
4655 		return len;
4656 
4657 	/* check if we are allowed to change */
4658 	if (mddev->delta_disks)
4659 		return -EBUSY;
4660 
4661 	if (mddev->persistent &&
4662 	    mddev->major_version == 0)
4663 		return -EINVAL;
4664 
4665 	mddev->reshape_backwards = backwards;
4666 	return len;
4667 }
4668 
4669 static struct md_sysfs_entry md_reshape_direction =
4670 __ATTR(reshape_direction, S_IRUGO|S_IWUSR, reshape_direction_show,
4671        reshape_direction_store);
4672 
4673 static ssize_t
4674 array_size_show(struct mddev *mddev, char *page)
4675 {
4676 	if (mddev->external_size)
4677 		return sprintf(page, "%llu\n",
4678 			       (unsigned long long)mddev->array_sectors/2);
4679 	else
4680 		return sprintf(page, "default\n");
4681 }
4682 
4683 static ssize_t
4684 array_size_store(struct mddev *mddev, const char *buf, size_t len)
4685 {
4686 	sector_t sectors;
4687 
4688 	if (strncmp(buf, "default", 7) == 0) {
4689 		if (mddev->pers)
4690 			sectors = mddev->pers->size(mddev, 0, 0);
4691 		else
4692 			sectors = mddev->array_sectors;
4693 
4694 		mddev->external_size = 0;
4695 	} else {
4696 		if (strict_blocks_to_sectors(buf, &sectors) < 0)
4697 			return -EINVAL;
4698 		if (mddev->pers && mddev->pers->size(mddev, 0, 0) < sectors)
4699 			return -E2BIG;
4700 
4701 		mddev->external_size = 1;
4702 	}
4703 
4704 	mddev->array_sectors = sectors;
4705 	if (mddev->pers) {
4706 		set_capacity(mddev->gendisk, mddev->array_sectors);
4707 		revalidate_disk(mddev->gendisk);
4708 	}
4709 	return len;
4710 }
4711 
4712 static struct md_sysfs_entry md_array_size =
4713 __ATTR(array_size, S_IRUGO|S_IWUSR, array_size_show,
4714        array_size_store);
4715 
4716 static struct attribute *md_default_attrs[] = {
4717 	&md_level.attr,
4718 	&md_layout.attr,
4719 	&md_raid_disks.attr,
4720 	&md_chunk_size.attr,
4721 	&md_size.attr,
4722 	&md_resync_start.attr,
4723 	&md_metadata.attr,
4724 	&md_new_device.attr,
4725 	&md_safe_delay.attr,
4726 	&md_array_state.attr,
4727 	&md_reshape_position.attr,
4728 	&md_reshape_direction.attr,
4729 	&md_array_size.attr,
4730 	&max_corr_read_errors.attr,
4731 	NULL,
4732 };
4733 
4734 static struct attribute *md_redundancy_attrs[] = {
4735 	&md_scan_mode.attr,
4736 	&md_mismatches.attr,
4737 	&md_sync_min.attr,
4738 	&md_sync_max.attr,
4739 	&md_sync_speed.attr,
4740 	&md_sync_force_parallel.attr,
4741 	&md_sync_completed.attr,
4742 	&md_min_sync.attr,
4743 	&md_max_sync.attr,
4744 	&md_suspend_lo.attr,
4745 	&md_suspend_hi.attr,
4746 	&md_bitmap.attr,
4747 	&md_degraded.attr,
4748 	NULL,
4749 };
4750 static struct attribute_group md_redundancy_group = {
4751 	.name = NULL,
4752 	.attrs = md_redundancy_attrs,
4753 };
4754 
4755 
4756 static ssize_t
4757 md_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
4758 {
4759 	struct md_sysfs_entry *entry = container_of(attr, struct md_sysfs_entry, attr);
4760 	struct mddev *mddev = container_of(kobj, struct mddev, kobj);
4761 	ssize_t rv;
4762 
4763 	if (!entry->show)
4764 		return -EIO;
4765 	spin_lock(&all_mddevs_lock);
4766 	if (list_empty(&mddev->all_mddevs)) {
4767 		spin_unlock(&all_mddevs_lock);
4768 		return -EBUSY;
4769 	}
4770 	mddev_get(mddev);
4771 	spin_unlock(&all_mddevs_lock);
4772 
4773 	rv = mddev_lock(mddev);
4774 	if (!rv) {
4775 		rv = entry->show(mddev, page);
4776 		mddev_unlock(mddev);
4777 	}
4778 	mddev_put(mddev);
4779 	return rv;
4780 }
4781 
4782 static ssize_t
4783 md_attr_store(struct kobject *kobj, struct attribute *attr,
4784 	      const char *page, size_t length)
4785 {
4786 	struct md_sysfs_entry *entry = container_of(attr, struct md_sysfs_entry, attr);
4787 	struct mddev *mddev = container_of(kobj, struct mddev, kobj);
4788 	ssize_t rv;
4789 
4790 	if (!entry->store)
4791 		return -EIO;
4792 	if (!capable(CAP_SYS_ADMIN))
4793 		return -EACCES;
4794 	spin_lock(&all_mddevs_lock);
4795 	if (list_empty(&mddev->all_mddevs)) {
4796 		spin_unlock(&all_mddevs_lock);
4797 		return -EBUSY;
4798 	}
4799 	mddev_get(mddev);
4800 	spin_unlock(&all_mddevs_lock);
4801 	rv = mddev_lock(mddev);
4802 	if (!rv) {
4803 		rv = entry->store(mddev, page, length);
4804 		mddev_unlock(mddev);
4805 	}
4806 	mddev_put(mddev);
4807 	return rv;
4808 }
4809 
4810 static void md_free(struct kobject *ko)
4811 {
4812 	struct mddev *mddev = container_of(ko, struct mddev, kobj);
4813 
4814 	if (mddev->sysfs_state)
4815 		sysfs_put(mddev->sysfs_state);
4816 
4817 	if (mddev->gendisk) {
4818 		del_gendisk(mddev->gendisk);
4819 		put_disk(mddev->gendisk);
4820 	}
4821 	if (mddev->queue)
4822 		blk_cleanup_queue(mddev->queue);
4823 
4824 	kfree(mddev);
4825 }
4826 
4827 static const struct sysfs_ops md_sysfs_ops = {
4828 	.show	= md_attr_show,
4829 	.store	= md_attr_store,
4830 };
4831 static struct kobj_type md_ktype = {
4832 	.release	= md_free,
4833 	.sysfs_ops	= &md_sysfs_ops,
4834 	.default_attrs	= md_default_attrs,
4835 };
4836 
4837 int mdp_major = 0;
4838 
4839 static void mddev_delayed_delete(struct work_struct *ws)
4840 {
4841 	struct mddev *mddev = container_of(ws, struct mddev, del_work);
4842 
4843 	sysfs_remove_group(&mddev->kobj, &md_bitmap_group);
4844 	kobject_del(&mddev->kobj);
4845 	kobject_put(&mddev->kobj);
4846 }
4847 
4848 static int md_alloc(dev_t dev, char *name)
4849 {
4850 	static DEFINE_MUTEX(disks_mutex);
4851 	struct mddev *mddev = mddev_find(dev);
4852 	struct gendisk *disk;
4853 	int partitioned;
4854 	int shift;
4855 	int unit;
4856 	int error;
4857 
4858 	if (!mddev)
4859 		return -ENODEV;
4860 
4861 	partitioned = (MAJOR(mddev->unit) != MD_MAJOR);
4862 	shift = partitioned ? MdpMinorShift : 0;
4863 	unit = MINOR(mddev->unit) >> shift;
4864 
4865 	/* wait for any previous instance of this device to be
4866 	 * completely removed (mddev_delayed_delete).
4867 	 */
4868 	flush_workqueue(md_misc_wq);
4869 
4870 	mutex_lock(&disks_mutex);
4871 	error = -EEXIST;
4872 	if (mddev->gendisk)
4873 		goto abort;
4874 
4875 	if (name) {
4876 		/* Need to ensure that 'name' is not a duplicate.
4877 		 */
4878 		struct mddev *mddev2;
4879 		spin_lock(&all_mddevs_lock);
4880 
4881 		list_for_each_entry(mddev2, &all_mddevs, all_mddevs)
4882 			if (mddev2->gendisk &&
4883 			    strcmp(mddev2->gendisk->disk_name, name) == 0) {
4884 				spin_unlock(&all_mddevs_lock);
4885 				goto abort;
4886 			}
4887 		spin_unlock(&all_mddevs_lock);
4888 	}
4889 
4890 	error = -ENOMEM;
4891 	mddev->queue = blk_alloc_queue(GFP_KERNEL);
4892 	if (!mddev->queue)
4893 		goto abort;
4894 	mddev->queue->queuedata = mddev;
4895 
4896 	blk_queue_make_request(mddev->queue, md_make_request);
4897 	blk_set_stacking_limits(&mddev->queue->limits);
4898 
4899 	disk = alloc_disk(1 << shift);
4900 	if (!disk) {
4901 		blk_cleanup_queue(mddev->queue);
4902 		mddev->queue = NULL;
4903 		goto abort;
4904 	}
4905 	disk->major = MAJOR(mddev->unit);
4906 	disk->first_minor = unit << shift;
4907 	if (name)
4908 		strcpy(disk->disk_name, name);
4909 	else if (partitioned)
4910 		sprintf(disk->disk_name, "md_d%d", unit);
4911 	else
4912 		sprintf(disk->disk_name, "md%d", unit);
4913 	disk->fops = &md_fops;
4914 	disk->private_data = mddev;
4915 	disk->queue = mddev->queue;
4916 	blk_queue_flush(mddev->queue, REQ_FLUSH | REQ_FUA);
4917 	/* Allow extended partitions.  This makes the
4918 	 * 'mdp' device redundant, but we can't really
4919 	 * remove it now.
4920 	 */
4921 	disk->flags |= GENHD_FL_EXT_DEVT;
4922 	mddev->gendisk = disk;
4923 	/* As soon as we call add_disk(), another thread could get
4924 	 * through to md_open, so make sure it doesn't get too far
4925 	 */
4926 	mutex_lock(&mddev->open_mutex);
4927 	add_disk(disk);
4928 
4929 	error = kobject_init_and_add(&mddev->kobj, &md_ktype,
4930 				     &disk_to_dev(disk)->kobj, "%s", "md");
4931 	if (error) {
4932 		/* This isn't possible, but as kobject_init_and_add is marked
4933 		 * __must_check, we must do something with the result
4934 		 */
4935 		printk(KERN_WARNING "md: cannot register %s/md - name in use\n",
4936 		       disk->disk_name);
4937 		error = 0;
4938 	}
4939 	if (mddev->kobj.sd &&
4940 	    sysfs_create_group(&mddev->kobj, &md_bitmap_group))
4941 		printk(KERN_DEBUG "pointless warning\n");
4942 	mutex_unlock(&mddev->open_mutex);
4943  abort:
4944 	mutex_unlock(&disks_mutex);
4945 	if (!error && mddev->kobj.sd) {
4946 		kobject_uevent(&mddev->kobj, KOBJ_ADD);
4947 		mddev->sysfs_state = sysfs_get_dirent_safe(mddev->kobj.sd, "array_state");
4948 	}
4949 	mddev_put(mddev);
4950 	return error;
4951 }
4952 
4953 static struct kobject *md_probe(dev_t dev, int *part, void *data)
4954 {
4955 	md_alloc(dev, NULL);
4956 	return NULL;
4957 }
4958 
4959 static int add_named_array(const char *val, struct kernel_param *kp)
4960 {
4961 	/* val must be "md_*" where * is not all digits.
4962 	 * We allocate an array with a large free minor number, and
4963 	 * set the name to val.  val must not already be an active name.
4964 	 */
4965 	int len = strlen(val);
4966 	char buf[DISK_NAME_LEN];
4967 
4968 	while (len && val[len-1] == '\n')
4969 		len--;
4970 	if (len >= DISK_NAME_LEN)
4971 		return -E2BIG;
4972 	strlcpy(buf, val, len+1);
4973 	if (strncmp(buf, "md_", 3) != 0)
4974 		return -EINVAL;
4975 	return md_alloc(0, buf);
4976 }
4977 
4978 static void md_safemode_timeout(unsigned long data)
4979 {
4980 	struct mddev *mddev = (struct mddev *) data;
4981 
4982 	if (!atomic_read(&mddev->writes_pending)) {
4983 		mddev->safemode = 1;
4984 		if (mddev->external)
4985 			sysfs_notify_dirent_safe(mddev->sysfs_state);
4986 	}
4987 	md_wakeup_thread(mddev->thread);
4988 }
4989 
4990 static int start_dirty_degraded;
4991 
4992 int md_run(struct mddev *mddev)
4993 {
4994 	int err;
4995 	struct md_rdev *rdev;
4996 	struct md_personality *pers;
4997 
4998 	if (list_empty(&mddev->disks))
4999 		/* cannot run an array with no devices.. */
5000 		return -EINVAL;
5001 
5002 	if (mddev->pers)
5003 		return -EBUSY;
5004 	/* Cannot run until previous stop completes properly */
5005 	if (mddev->sysfs_active)
5006 		return -EBUSY;
5007 
5008 	/*
5009 	 * Analyze all RAID superblock(s)
5010 	 */
5011 	if (!mddev->raid_disks) {
5012 		if (!mddev->persistent)
5013 			return -EINVAL;
5014 		analyze_sbs(mddev);
5015 	}
5016 
5017 	if (mddev->level != LEVEL_NONE)
5018 		request_module("md-level-%d", mddev->level);
5019 	else if (mddev->clevel[0])
5020 		request_module("md-%s", mddev->clevel);
5021 
5022 	/*
5023 	 * Drop all container device buffers, from now on
5024 	 * the only valid external interface is through the md
5025 	 * device.
5026 	 */
5027 	rdev_for_each(rdev, mddev) {
5028 		if (test_bit(Faulty, &rdev->flags))
5029 			continue;
5030 		sync_blockdev(rdev->bdev);
5031 		invalidate_bdev(rdev->bdev);
5032 
5033 		/* perform some consistency tests on the device.
5034 		 * We don't want the data to overlap the metadata,
5035 		 * Internal Bitmap issues have been handled elsewhere.
5036 		 */
5037 		if (rdev->meta_bdev) {
5038 			/* Nothing to check */;
5039 		} else if (rdev->data_offset < rdev->sb_start) {
5040 			if (mddev->dev_sectors &&
5041 			    rdev->data_offset + mddev->dev_sectors
5042 			    > rdev->sb_start) {
5043 				printk("md: %s: data overlaps metadata\n",
5044 				       mdname(mddev));
5045 				return -EINVAL;
5046 			}
5047 		} else {
5048 			if (rdev->sb_start + rdev->sb_size/512
5049 			    > rdev->data_offset) {
5050 				printk("md: %s: metadata overlaps data\n",
5051 				       mdname(mddev));
5052 				return -EINVAL;
5053 			}
5054 		}
5055 		sysfs_notify_dirent_safe(rdev->sysfs_state);
5056 	}
5057 
5058 	if (mddev->bio_set == NULL)
5059 		mddev->bio_set = bioset_create(BIO_POOL_SIZE,
5060 					       sizeof(struct mddev *));
5061 
5062 	spin_lock(&pers_lock);
5063 	pers = find_pers(mddev->level, mddev->clevel);
5064 	if (!pers || !try_module_get(pers->owner)) {
5065 		spin_unlock(&pers_lock);
5066 		if (mddev->level != LEVEL_NONE)
5067 			printk(KERN_WARNING "md: personality for level %d is not loaded!\n",
5068 			       mddev->level);
5069 		else
5070 			printk(KERN_WARNING "md: personality for level %s is not loaded!\n",
5071 			       mddev->clevel);
5072 		return -EINVAL;
5073 	}
5074 	mddev->pers = pers;
5075 	spin_unlock(&pers_lock);
5076 	if (mddev->level != pers->level) {
5077 		mddev->level = pers->level;
5078 		mddev->new_level = pers->level;
5079 	}
5080 	strlcpy(mddev->clevel, pers->name, sizeof(mddev->clevel));
5081 
5082 	if (mddev->reshape_position != MaxSector &&
5083 	    pers->start_reshape == NULL) {
5084 		/* This personality cannot handle reshaping... */
5085 		mddev->pers = NULL;
5086 		module_put(pers->owner);
5087 		return -EINVAL;
5088 	}
5089 
5090 	if (pers->sync_request) {
5091 		/* Warn if this is a potentially silly
5092 		 * configuration.
5093 		 */
5094 		char b[BDEVNAME_SIZE], b2[BDEVNAME_SIZE];
5095 		struct md_rdev *rdev2;
5096 		int warned = 0;
5097 
5098 		rdev_for_each(rdev, mddev)
5099 			rdev_for_each(rdev2, mddev) {
5100 				if (rdev < rdev2 &&
5101 				    rdev->bdev->bd_contains ==
5102 				    rdev2->bdev->bd_contains) {
5103 					printk(KERN_WARNING
5104 					       "%s: WARNING: %s appears to be"
5105 					       " on the same physical disk as"
5106 					       " %s.\n",
5107 					       mdname(mddev),
5108 					       bdevname(rdev->bdev,b),
5109 					       bdevname(rdev2->bdev,b2));
5110 					warned = 1;
5111 				}
5112 			}
5113 
5114 		if (warned)
5115 			printk(KERN_WARNING
5116 			       "True protection against single-disk"
5117 			       " failure might be compromised.\n");
5118 	}
5119 
5120 	mddev->recovery = 0;
5121 	/* may be over-ridden by personality */
5122 	mddev->resync_max_sectors = mddev->dev_sectors;
5123 
5124 	mddev->ok_start_degraded = start_dirty_degraded;
5125 
5126 	if (start_readonly && mddev->ro == 0)
5127 		mddev->ro = 2; /* read-only, but switch on first write */
5128 
5129 	err = mddev->pers->run(mddev);
5130 	if (err)
5131 		printk(KERN_ERR "md: pers->run() failed ...\n");
5132 	else if (mddev->pers->size(mddev, 0, 0) < mddev->array_sectors) {
5133 		WARN_ONCE(!mddev->external_size, "%s: default size too small,"
5134 			  " but 'external_size' not in effect?\n", __func__);
5135 		printk(KERN_ERR
5136 		       "md: invalid array_size %llu > default size %llu\n",
5137 		       (unsigned long long)mddev->array_sectors / 2,
5138 		       (unsigned long long)mddev->pers->size(mddev, 0, 0) / 2);
5139 		err = -EINVAL;
5140 		mddev->pers->stop(mddev);
5141 	}
5142 	if (err == 0 && mddev->pers->sync_request &&
5143 	    (mddev->bitmap_info.file || mddev->bitmap_info.offset)) {
5144 		err = bitmap_create(mddev);
5145 		if (err) {
5146 			printk(KERN_ERR "%s: failed to create bitmap (%d)\n",
5147 			       mdname(mddev), err);
5148 			mddev->pers->stop(mddev);
5149 		}
5150 	}
5151 	if (err) {
5152 		module_put(mddev->pers->owner);
5153 		mddev->pers = NULL;
5154 		bitmap_destroy(mddev);
5155 		return err;
5156 	}
5157 	if (mddev->pers->sync_request) {
5158 		if (mddev->kobj.sd &&
5159 		    sysfs_create_group(&mddev->kobj, &md_redundancy_group))
5160 			printk(KERN_WARNING
5161 			       "md: cannot register extra attributes for %s\n",
5162 			       mdname(mddev));
5163 		mddev->sysfs_action = sysfs_get_dirent_safe(mddev->kobj.sd, "sync_action");
5164 	} else if (mddev->ro == 2) /* auto-readonly not meaningful */
5165 		mddev->ro = 0;
5166 
5167  	atomic_set(&mddev->writes_pending,0);
5168 	atomic_set(&mddev->max_corr_read_errors,
5169 		   MD_DEFAULT_MAX_CORRECTED_READ_ERRORS);
5170 	mddev->safemode = 0;
5171 	mddev->safemode_timer.function = md_safemode_timeout;
5172 	mddev->safemode_timer.data = (unsigned long) mddev;
5173 	mddev->safemode_delay = (200 * HZ)/1000 +1; /* 200 msec delay */
5174 	mddev->in_sync = 1;
5175 	smp_wmb();
5176 	mddev->ready = 1;
5177 	rdev_for_each(rdev, mddev)
5178 		if (rdev->raid_disk >= 0)
5179 			if (sysfs_link_rdev(mddev, rdev))
5180 				/* failure here is OK */;
5181 
5182 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
5183 
5184 	if (mddev->flags)
5185 		md_update_sb(mddev, 0);
5186 
5187 	md_new_event(mddev);
5188 	sysfs_notify_dirent_safe(mddev->sysfs_state);
5189 	sysfs_notify_dirent_safe(mddev->sysfs_action);
5190 	sysfs_notify(&mddev->kobj, NULL, "degraded");
5191 	return 0;
5192 }
5193 EXPORT_SYMBOL_GPL(md_run);
5194 
5195 static int do_md_run(struct mddev *mddev)
5196 {
5197 	int err;
5198 
5199 	err = md_run(mddev);
5200 	if (err)
5201 		goto out;
5202 	err = bitmap_load(mddev);
5203 	if (err) {
5204 		bitmap_destroy(mddev);
5205 		goto out;
5206 	}
5207 
5208 	md_wakeup_thread(mddev->thread);
5209 	md_wakeup_thread(mddev->sync_thread); /* possibly kick off a reshape */
5210 
5211 	set_capacity(mddev->gendisk, mddev->array_sectors);
5212 	revalidate_disk(mddev->gendisk);
5213 	mddev->changed = 1;
5214 	kobject_uevent(&disk_to_dev(mddev->gendisk)->kobj, KOBJ_CHANGE);
5215 out:
5216 	return err;
5217 }
5218 
5219 static int restart_array(struct mddev *mddev)
5220 {
5221 	struct gendisk *disk = mddev->gendisk;
5222 
5223 	/* Complain if it has no devices */
5224 	if (list_empty(&mddev->disks))
5225 		return -ENXIO;
5226 	if (!mddev->pers)
5227 		return -EINVAL;
5228 	if (!mddev->ro)
5229 		return -EBUSY;
5230 	mddev->safemode = 0;
5231 	mddev->ro = 0;
5232 	set_disk_ro(disk, 0);
5233 	printk(KERN_INFO "md: %s switched to read-write mode.\n",
5234 		mdname(mddev));
5235 	/* Kick recovery or resync if necessary */
5236 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
5237 	md_wakeup_thread(mddev->thread);
5238 	md_wakeup_thread(mddev->sync_thread);
5239 	sysfs_notify_dirent_safe(mddev->sysfs_state);
5240 	return 0;
5241 }
5242 
5243 /* similar to deny_write_access, but accounts for our holding a reference
5244  * to the file ourselves */
5245 static int deny_bitmap_write_access(struct file * file)
5246 {
5247 	struct inode *inode = file->f_mapping->host;
5248 
5249 	spin_lock(&inode->i_lock);
5250 	if (atomic_read(&inode->i_writecount) > 1) {
5251 		spin_unlock(&inode->i_lock);
5252 		return -ETXTBSY;
5253 	}
5254 	atomic_set(&inode->i_writecount, -1);
5255 	spin_unlock(&inode->i_lock);
5256 
5257 	return 0;
5258 }
5259 
5260 void restore_bitmap_write_access(struct file *file)
5261 {
5262 	struct inode *inode = file->f_mapping->host;
5263 
5264 	spin_lock(&inode->i_lock);
5265 	atomic_set(&inode->i_writecount, 1);
5266 	spin_unlock(&inode->i_lock);
5267 }
5268 
5269 static void md_clean(struct mddev *mddev)
5270 {
5271 	mddev->array_sectors = 0;
5272 	mddev->external_size = 0;
5273 	mddev->dev_sectors = 0;
5274 	mddev->raid_disks = 0;
5275 	mddev->recovery_cp = 0;
5276 	mddev->resync_min = 0;
5277 	mddev->resync_max = MaxSector;
5278 	mddev->reshape_position = MaxSector;
5279 	mddev->external = 0;
5280 	mddev->persistent = 0;
5281 	mddev->level = LEVEL_NONE;
5282 	mddev->clevel[0] = 0;
5283 	mddev->flags = 0;
5284 	mddev->ro = 0;
5285 	mddev->metadata_type[0] = 0;
5286 	mddev->chunk_sectors = 0;
5287 	mddev->ctime = mddev->utime = 0;
5288 	mddev->layout = 0;
5289 	mddev->max_disks = 0;
5290 	mddev->events = 0;
5291 	mddev->can_decrease_events = 0;
5292 	mddev->delta_disks = 0;
5293 	mddev->reshape_backwards = 0;
5294 	mddev->new_level = LEVEL_NONE;
5295 	mddev->new_layout = 0;
5296 	mddev->new_chunk_sectors = 0;
5297 	mddev->curr_resync = 0;
5298 	mddev->resync_mismatches = 0;
5299 	mddev->suspend_lo = mddev->suspend_hi = 0;
5300 	mddev->sync_speed_min = mddev->sync_speed_max = 0;
5301 	mddev->recovery = 0;
5302 	mddev->in_sync = 0;
5303 	mddev->changed = 0;
5304 	mddev->degraded = 0;
5305 	mddev->safemode = 0;
5306 	mddev->merge_check_needed = 0;
5307 	mddev->bitmap_info.offset = 0;
5308 	mddev->bitmap_info.default_offset = 0;
5309 	mddev->bitmap_info.default_space = 0;
5310 	mddev->bitmap_info.chunksize = 0;
5311 	mddev->bitmap_info.daemon_sleep = 0;
5312 	mddev->bitmap_info.max_write_behind = 0;
5313 }
5314 
5315 static void __md_stop_writes(struct mddev *mddev)
5316 {
5317 	if (mddev->sync_thread) {
5318 		set_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
5319 		set_bit(MD_RECOVERY_INTR, &mddev->recovery);
5320 		reap_sync_thread(mddev);
5321 	}
5322 
5323 	del_timer_sync(&mddev->safemode_timer);
5324 
5325 	bitmap_flush(mddev);
5326 	md_super_wait(mddev);
5327 
5328 	if (!mddev->in_sync || mddev->flags) {
5329 		/* mark array as shutdown cleanly */
5330 		mddev->in_sync = 1;
5331 		md_update_sb(mddev, 1);
5332 	}
5333 }
5334 
5335 void md_stop_writes(struct mddev *mddev)
5336 {
5337 	mddev_lock(mddev);
5338 	__md_stop_writes(mddev);
5339 	mddev_unlock(mddev);
5340 }
5341 EXPORT_SYMBOL_GPL(md_stop_writes);
5342 
5343 void md_stop(struct mddev *mddev)
5344 {
5345 	mddev->ready = 0;
5346 	mddev->pers->stop(mddev);
5347 	if (mddev->pers->sync_request && mddev->to_remove == NULL)
5348 		mddev->to_remove = &md_redundancy_group;
5349 	module_put(mddev->pers->owner);
5350 	mddev->pers = NULL;
5351 	clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
5352 }
5353 EXPORT_SYMBOL_GPL(md_stop);
5354 
5355 static int md_set_readonly(struct mddev *mddev, struct block_device *bdev)
5356 {
5357 	int err = 0;
5358 	mutex_lock(&mddev->open_mutex);
5359 	if (atomic_read(&mddev->openers) > !!bdev) {
5360 		printk("md: %s still in use.\n",mdname(mddev));
5361 		err = -EBUSY;
5362 		goto out;
5363 	}
5364 	if (bdev)
5365 		sync_blockdev(bdev);
5366 	if (mddev->pers) {
5367 		__md_stop_writes(mddev);
5368 
5369 		err  = -ENXIO;
5370 		if (mddev->ro==1)
5371 			goto out;
5372 		mddev->ro = 1;
5373 		set_disk_ro(mddev->gendisk, 1);
5374 		clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
5375 		sysfs_notify_dirent_safe(mddev->sysfs_state);
5376 		err = 0;
5377 	}
5378 out:
5379 	mutex_unlock(&mddev->open_mutex);
5380 	return err;
5381 }
5382 
5383 /* mode:
5384  *   0 - completely stop and dis-assemble array
5385  *   2 - stop but do not disassemble array
5386  */
5387 static int do_md_stop(struct mddev * mddev, int mode,
5388 		      struct block_device *bdev)
5389 {
5390 	struct gendisk *disk = mddev->gendisk;
5391 	struct md_rdev *rdev;
5392 
5393 	mutex_lock(&mddev->open_mutex);
5394 	if (atomic_read(&mddev->openers) > !!bdev ||
5395 	    mddev->sysfs_active) {
5396 		printk("md: %s still in use.\n",mdname(mddev));
5397 		mutex_unlock(&mddev->open_mutex);
5398 		return -EBUSY;
5399 	}
5400 	if (bdev)
5401 		/* It is possible IO was issued on some other
5402 		 * open file which was closed before we took ->open_mutex.
5403 		 * As that was not the last close __blkdev_put will not
5404 		 * have called sync_blockdev, so we must.
5405 		 */
5406 		sync_blockdev(bdev);
5407 
5408 	if (mddev->pers) {
5409 		if (mddev->ro)
5410 			set_disk_ro(disk, 0);
5411 
5412 		__md_stop_writes(mddev);
5413 		md_stop(mddev);
5414 		mddev->queue->merge_bvec_fn = NULL;
5415 		mddev->queue->backing_dev_info.congested_fn = NULL;
5416 
5417 		/* tell userspace to handle 'inactive' */
5418 		sysfs_notify_dirent_safe(mddev->sysfs_state);
5419 
5420 		rdev_for_each(rdev, mddev)
5421 			if (rdev->raid_disk >= 0)
5422 				sysfs_unlink_rdev(mddev, rdev);
5423 
5424 		set_capacity(disk, 0);
5425 		mutex_unlock(&mddev->open_mutex);
5426 		mddev->changed = 1;
5427 		revalidate_disk(disk);
5428 
5429 		if (mddev->ro)
5430 			mddev->ro = 0;
5431 	} else
5432 		mutex_unlock(&mddev->open_mutex);
5433 	/*
5434 	 * Free resources if final stop
5435 	 */
5436 	if (mode == 0) {
5437 		printk(KERN_INFO "md: %s stopped.\n", mdname(mddev));
5438 
5439 		bitmap_destroy(mddev);
5440 		if (mddev->bitmap_info.file) {
5441 			restore_bitmap_write_access(mddev->bitmap_info.file);
5442 			fput(mddev->bitmap_info.file);
5443 			mddev->bitmap_info.file = NULL;
5444 		}
5445 		mddev->bitmap_info.offset = 0;
5446 
5447 		export_array(mddev);
5448 
5449 		md_clean(mddev);
5450 		kobject_uevent(&disk_to_dev(mddev->gendisk)->kobj, KOBJ_CHANGE);
5451 		if (mddev->hold_active == UNTIL_STOP)
5452 			mddev->hold_active = 0;
5453 	}
5454 	blk_integrity_unregister(disk);
5455 	md_new_event(mddev);
5456 	sysfs_notify_dirent_safe(mddev->sysfs_state);
5457 	return 0;
5458 }
5459 
5460 #ifndef MODULE
5461 static void autorun_array(struct mddev *mddev)
5462 {
5463 	struct md_rdev *rdev;
5464 	int err;
5465 
5466 	if (list_empty(&mddev->disks))
5467 		return;
5468 
5469 	printk(KERN_INFO "md: running: ");
5470 
5471 	rdev_for_each(rdev, mddev) {
5472 		char b[BDEVNAME_SIZE];
5473 		printk("<%s>", bdevname(rdev->bdev,b));
5474 	}
5475 	printk("\n");
5476 
5477 	err = do_md_run(mddev);
5478 	if (err) {
5479 		printk(KERN_WARNING "md: do_md_run() returned %d\n", err);
5480 		do_md_stop(mddev, 0, NULL);
5481 	}
5482 }
5483 
5484 /*
5485  * lets try to run arrays based on all disks that have arrived
5486  * until now. (those are in pending_raid_disks)
5487  *
5488  * the method: pick the first pending disk, collect all disks with
5489  * the same UUID, remove all from the pending list and put them into
5490  * the 'same_array' list. Then order this list based on superblock
5491  * update time (freshest comes first), kick out 'old' disks and
5492  * compare superblocks. If everything's fine then run it.
5493  *
5494  * If "unit" is allocated, then bump its reference count
5495  */
5496 static void autorun_devices(int part)
5497 {
5498 	struct md_rdev *rdev0, *rdev, *tmp;
5499 	struct mddev *mddev;
5500 	char b[BDEVNAME_SIZE];
5501 
5502 	printk(KERN_INFO "md: autorun ...\n");
5503 	while (!list_empty(&pending_raid_disks)) {
5504 		int unit;
5505 		dev_t dev;
5506 		LIST_HEAD(candidates);
5507 		rdev0 = list_entry(pending_raid_disks.next,
5508 					 struct md_rdev, same_set);
5509 
5510 		printk(KERN_INFO "md: considering %s ...\n",
5511 			bdevname(rdev0->bdev,b));
5512 		INIT_LIST_HEAD(&candidates);
5513 		rdev_for_each_list(rdev, tmp, &pending_raid_disks)
5514 			if (super_90_load(rdev, rdev0, 0) >= 0) {
5515 				printk(KERN_INFO "md:  adding %s ...\n",
5516 					bdevname(rdev->bdev,b));
5517 				list_move(&rdev->same_set, &candidates);
5518 			}
5519 		/*
5520 		 * now we have a set of devices, with all of them having
5521 		 * mostly sane superblocks. It's time to allocate the
5522 		 * mddev.
5523 		 */
5524 		if (part) {
5525 			dev = MKDEV(mdp_major,
5526 				    rdev0->preferred_minor << MdpMinorShift);
5527 			unit = MINOR(dev) >> MdpMinorShift;
5528 		} else {
5529 			dev = MKDEV(MD_MAJOR, rdev0->preferred_minor);
5530 			unit = MINOR(dev);
5531 		}
5532 		if (rdev0->preferred_minor != unit) {
5533 			printk(KERN_INFO "md: unit number in %s is bad: %d\n",
5534 			       bdevname(rdev0->bdev, b), rdev0->preferred_minor);
5535 			break;
5536 		}
5537 
5538 		md_probe(dev, NULL, NULL);
5539 		mddev = mddev_find(dev);
5540 		if (!mddev || !mddev->gendisk) {
5541 			if (mddev)
5542 				mddev_put(mddev);
5543 			printk(KERN_ERR
5544 				"md: cannot allocate memory for md drive.\n");
5545 			break;
5546 		}
5547 		if (mddev_lock(mddev))
5548 			printk(KERN_WARNING "md: %s locked, cannot run\n",
5549 			       mdname(mddev));
5550 		else if (mddev->raid_disks || mddev->major_version
5551 			 || !list_empty(&mddev->disks)) {
5552 			printk(KERN_WARNING
5553 				"md: %s already running, cannot run %s\n",
5554 				mdname(mddev), bdevname(rdev0->bdev,b));
5555 			mddev_unlock(mddev);
5556 		} else {
5557 			printk(KERN_INFO "md: created %s\n", mdname(mddev));
5558 			mddev->persistent = 1;
5559 			rdev_for_each_list(rdev, tmp, &candidates) {
5560 				list_del_init(&rdev->same_set);
5561 				if (bind_rdev_to_array(rdev, mddev))
5562 					export_rdev(rdev);
5563 			}
5564 			autorun_array(mddev);
5565 			mddev_unlock(mddev);
5566 		}
5567 		/* on success, candidates will be empty, on error
5568 		 * it won't...
5569 		 */
5570 		rdev_for_each_list(rdev, tmp, &candidates) {
5571 			list_del_init(&rdev->same_set);
5572 			export_rdev(rdev);
5573 		}
5574 		mddev_put(mddev);
5575 	}
5576 	printk(KERN_INFO "md: ... autorun DONE.\n");
5577 }
5578 #endif /* !MODULE */
5579 
5580 static int get_version(void __user * arg)
5581 {
5582 	mdu_version_t ver;
5583 
5584 	ver.major = MD_MAJOR_VERSION;
5585 	ver.minor = MD_MINOR_VERSION;
5586 	ver.patchlevel = MD_PATCHLEVEL_VERSION;
5587 
5588 	if (copy_to_user(arg, &ver, sizeof(ver)))
5589 		return -EFAULT;
5590 
5591 	return 0;
5592 }
5593 
5594 static int get_array_info(struct mddev * mddev, void __user * arg)
5595 {
5596 	mdu_array_info_t info;
5597 	int nr,working,insync,failed,spare;
5598 	struct md_rdev *rdev;
5599 
5600 	nr=working=insync=failed=spare=0;
5601 	rdev_for_each(rdev, mddev) {
5602 		nr++;
5603 		if (test_bit(Faulty, &rdev->flags))
5604 			failed++;
5605 		else {
5606 			working++;
5607 			if (test_bit(In_sync, &rdev->flags))
5608 				insync++;
5609 			else
5610 				spare++;
5611 		}
5612 	}
5613 
5614 	info.major_version = mddev->major_version;
5615 	info.minor_version = mddev->minor_version;
5616 	info.patch_version = MD_PATCHLEVEL_VERSION;
5617 	info.ctime         = mddev->ctime;
5618 	info.level         = mddev->level;
5619 	info.size          = mddev->dev_sectors / 2;
5620 	if (info.size != mddev->dev_sectors / 2) /* overflow */
5621 		info.size = -1;
5622 	info.nr_disks      = nr;
5623 	info.raid_disks    = mddev->raid_disks;
5624 	info.md_minor      = mddev->md_minor;
5625 	info.not_persistent= !mddev->persistent;
5626 
5627 	info.utime         = mddev->utime;
5628 	info.state         = 0;
5629 	if (mddev->in_sync)
5630 		info.state = (1<<MD_SB_CLEAN);
5631 	if (mddev->bitmap && mddev->bitmap_info.offset)
5632 		info.state = (1<<MD_SB_BITMAP_PRESENT);
5633 	info.active_disks  = insync;
5634 	info.working_disks = working;
5635 	info.failed_disks  = failed;
5636 	info.spare_disks   = spare;
5637 
5638 	info.layout        = mddev->layout;
5639 	info.chunk_size    = mddev->chunk_sectors << 9;
5640 
5641 	if (copy_to_user(arg, &info, sizeof(info)))
5642 		return -EFAULT;
5643 
5644 	return 0;
5645 }
5646 
5647 static int get_bitmap_file(struct mddev * mddev, void __user * arg)
5648 {
5649 	mdu_bitmap_file_t *file = NULL; /* too big for stack allocation */
5650 	char *ptr, *buf = NULL;
5651 	int err = -ENOMEM;
5652 
5653 	if (md_allow_write(mddev))
5654 		file = kmalloc(sizeof(*file), GFP_NOIO);
5655 	else
5656 		file = kmalloc(sizeof(*file), GFP_KERNEL);
5657 
5658 	if (!file)
5659 		goto out;
5660 
5661 	/* bitmap disabled, zero the first byte and copy out */
5662 	if (!mddev->bitmap || !mddev->bitmap->storage.file) {
5663 		file->pathname[0] = '\0';
5664 		goto copy_out;
5665 	}
5666 
5667 	buf = kmalloc(sizeof(file->pathname), GFP_KERNEL);
5668 	if (!buf)
5669 		goto out;
5670 
5671 	ptr = d_path(&mddev->bitmap->storage.file->f_path,
5672 		     buf, sizeof(file->pathname));
5673 	if (IS_ERR(ptr))
5674 		goto out;
5675 
5676 	strcpy(file->pathname, ptr);
5677 
5678 copy_out:
5679 	err = 0;
5680 	if (copy_to_user(arg, file, sizeof(*file)))
5681 		err = -EFAULT;
5682 out:
5683 	kfree(buf);
5684 	kfree(file);
5685 	return err;
5686 }
5687 
5688 static int get_disk_info(struct mddev * mddev, void __user * arg)
5689 {
5690 	mdu_disk_info_t info;
5691 	struct md_rdev *rdev;
5692 
5693 	if (copy_from_user(&info, arg, sizeof(info)))
5694 		return -EFAULT;
5695 
5696 	rdev = find_rdev_nr(mddev, info.number);
5697 	if (rdev) {
5698 		info.major = MAJOR(rdev->bdev->bd_dev);
5699 		info.minor = MINOR(rdev->bdev->bd_dev);
5700 		info.raid_disk = rdev->raid_disk;
5701 		info.state = 0;
5702 		if (test_bit(Faulty, &rdev->flags))
5703 			info.state |= (1<<MD_DISK_FAULTY);
5704 		else if (test_bit(In_sync, &rdev->flags)) {
5705 			info.state |= (1<<MD_DISK_ACTIVE);
5706 			info.state |= (1<<MD_DISK_SYNC);
5707 		}
5708 		if (test_bit(WriteMostly, &rdev->flags))
5709 			info.state |= (1<<MD_DISK_WRITEMOSTLY);
5710 	} else {
5711 		info.major = info.minor = 0;
5712 		info.raid_disk = -1;
5713 		info.state = (1<<MD_DISK_REMOVED);
5714 	}
5715 
5716 	if (copy_to_user(arg, &info, sizeof(info)))
5717 		return -EFAULT;
5718 
5719 	return 0;
5720 }
5721 
5722 static int add_new_disk(struct mddev * mddev, mdu_disk_info_t *info)
5723 {
5724 	char b[BDEVNAME_SIZE], b2[BDEVNAME_SIZE];
5725 	struct md_rdev *rdev;
5726 	dev_t dev = MKDEV(info->major,info->minor);
5727 
5728 	if (info->major != MAJOR(dev) || info->minor != MINOR(dev))
5729 		return -EOVERFLOW;
5730 
5731 	if (!mddev->raid_disks) {
5732 		int err;
5733 		/* expecting a device which has a superblock */
5734 		rdev = md_import_device(dev, mddev->major_version, mddev->minor_version);
5735 		if (IS_ERR(rdev)) {
5736 			printk(KERN_WARNING
5737 				"md: md_import_device returned %ld\n",
5738 				PTR_ERR(rdev));
5739 			return PTR_ERR(rdev);
5740 		}
5741 		if (!list_empty(&mddev->disks)) {
5742 			struct md_rdev *rdev0
5743 				= list_entry(mddev->disks.next,
5744 					     struct md_rdev, same_set);
5745 			err = super_types[mddev->major_version]
5746 				.load_super(rdev, rdev0, mddev->minor_version);
5747 			if (err < 0) {
5748 				printk(KERN_WARNING
5749 					"md: %s has different UUID to %s\n",
5750 					bdevname(rdev->bdev,b),
5751 					bdevname(rdev0->bdev,b2));
5752 				export_rdev(rdev);
5753 				return -EINVAL;
5754 			}
5755 		}
5756 		err = bind_rdev_to_array(rdev, mddev);
5757 		if (err)
5758 			export_rdev(rdev);
5759 		return err;
5760 	}
5761 
5762 	/*
5763 	 * add_new_disk can be used once the array is assembled
5764 	 * to add "hot spares".  They must already have a superblock
5765 	 * written
5766 	 */
5767 	if (mddev->pers) {
5768 		int err;
5769 		if (!mddev->pers->hot_add_disk) {
5770 			printk(KERN_WARNING
5771 				"%s: personality does not support diskops!\n",
5772 			       mdname(mddev));
5773 			return -EINVAL;
5774 		}
5775 		if (mddev->persistent)
5776 			rdev = md_import_device(dev, mddev->major_version,
5777 						mddev->minor_version);
5778 		else
5779 			rdev = md_import_device(dev, -1, -1);
5780 		if (IS_ERR(rdev)) {
5781 			printk(KERN_WARNING
5782 				"md: md_import_device returned %ld\n",
5783 				PTR_ERR(rdev));
5784 			return PTR_ERR(rdev);
5785 		}
5786 		/* set saved_raid_disk if appropriate */
5787 		if (!mddev->persistent) {
5788 			if (info->state & (1<<MD_DISK_SYNC)  &&
5789 			    info->raid_disk < mddev->raid_disks) {
5790 				rdev->raid_disk = info->raid_disk;
5791 				set_bit(In_sync, &rdev->flags);
5792 			} else
5793 				rdev->raid_disk = -1;
5794 		} else
5795 			super_types[mddev->major_version].
5796 				validate_super(mddev, rdev);
5797 		if ((info->state & (1<<MD_DISK_SYNC)) &&
5798 		     rdev->raid_disk != info->raid_disk) {
5799 			/* This was a hot-add request, but events doesn't
5800 			 * match, so reject it.
5801 			 */
5802 			export_rdev(rdev);
5803 			return -EINVAL;
5804 		}
5805 
5806 		if (test_bit(In_sync, &rdev->flags))
5807 			rdev->saved_raid_disk = rdev->raid_disk;
5808 		else
5809 			rdev->saved_raid_disk = -1;
5810 
5811 		clear_bit(In_sync, &rdev->flags); /* just to be sure */
5812 		if (info->state & (1<<MD_DISK_WRITEMOSTLY))
5813 			set_bit(WriteMostly, &rdev->flags);
5814 		else
5815 			clear_bit(WriteMostly, &rdev->flags);
5816 
5817 		rdev->raid_disk = -1;
5818 		err = bind_rdev_to_array(rdev, mddev);
5819 		if (!err && !mddev->pers->hot_remove_disk) {
5820 			/* If there is hot_add_disk but no hot_remove_disk
5821 			 * then added disks for geometry changes,
5822 			 * and should be added immediately.
5823 			 */
5824 			super_types[mddev->major_version].
5825 				validate_super(mddev, rdev);
5826 			err = mddev->pers->hot_add_disk(mddev, rdev);
5827 			if (err)
5828 				unbind_rdev_from_array(rdev);
5829 		}
5830 		if (err)
5831 			export_rdev(rdev);
5832 		else
5833 			sysfs_notify_dirent_safe(rdev->sysfs_state);
5834 
5835 		md_update_sb(mddev, 1);
5836 		if (mddev->degraded)
5837 			set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
5838 		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
5839 		if (!err)
5840 			md_new_event(mddev);
5841 		md_wakeup_thread(mddev->thread);
5842 		return err;
5843 	}
5844 
5845 	/* otherwise, add_new_disk is only allowed
5846 	 * for major_version==0 superblocks
5847 	 */
5848 	if (mddev->major_version != 0) {
5849 		printk(KERN_WARNING "%s: ADD_NEW_DISK not supported\n",
5850 		       mdname(mddev));
5851 		return -EINVAL;
5852 	}
5853 
5854 	if (!(info->state & (1<<MD_DISK_FAULTY))) {
5855 		int err;
5856 		rdev = md_import_device(dev, -1, 0);
5857 		if (IS_ERR(rdev)) {
5858 			printk(KERN_WARNING
5859 				"md: error, md_import_device() returned %ld\n",
5860 				PTR_ERR(rdev));
5861 			return PTR_ERR(rdev);
5862 		}
5863 		rdev->desc_nr = info->number;
5864 		if (info->raid_disk < mddev->raid_disks)
5865 			rdev->raid_disk = info->raid_disk;
5866 		else
5867 			rdev->raid_disk = -1;
5868 
5869 		if (rdev->raid_disk < mddev->raid_disks)
5870 			if (info->state & (1<<MD_DISK_SYNC))
5871 				set_bit(In_sync, &rdev->flags);
5872 
5873 		if (info->state & (1<<MD_DISK_WRITEMOSTLY))
5874 			set_bit(WriteMostly, &rdev->flags);
5875 
5876 		if (!mddev->persistent) {
5877 			printk(KERN_INFO "md: nonpersistent superblock ...\n");
5878 			rdev->sb_start = i_size_read(rdev->bdev->bd_inode) / 512;
5879 		} else
5880 			rdev->sb_start = calc_dev_sboffset(rdev);
5881 		rdev->sectors = rdev->sb_start;
5882 
5883 		err = bind_rdev_to_array(rdev, mddev);
5884 		if (err) {
5885 			export_rdev(rdev);
5886 			return err;
5887 		}
5888 	}
5889 
5890 	return 0;
5891 }
5892 
5893 static int hot_remove_disk(struct mddev * mddev, dev_t dev)
5894 {
5895 	char b[BDEVNAME_SIZE];
5896 	struct md_rdev *rdev;
5897 
5898 	rdev = find_rdev(mddev, dev);
5899 	if (!rdev)
5900 		return -ENXIO;
5901 
5902 	if (rdev->raid_disk >= 0)
5903 		goto busy;
5904 
5905 	kick_rdev_from_array(rdev);
5906 	md_update_sb(mddev, 1);
5907 	md_new_event(mddev);
5908 
5909 	return 0;
5910 busy:
5911 	printk(KERN_WARNING "md: cannot remove active disk %s from %s ...\n",
5912 		bdevname(rdev->bdev,b), mdname(mddev));
5913 	return -EBUSY;
5914 }
5915 
5916 static int hot_add_disk(struct mddev * mddev, dev_t dev)
5917 {
5918 	char b[BDEVNAME_SIZE];
5919 	int err;
5920 	struct md_rdev *rdev;
5921 
5922 	if (!mddev->pers)
5923 		return -ENODEV;
5924 
5925 	if (mddev->major_version != 0) {
5926 		printk(KERN_WARNING "%s: HOT_ADD may only be used with"
5927 			" version-0 superblocks.\n",
5928 			mdname(mddev));
5929 		return -EINVAL;
5930 	}
5931 	if (!mddev->pers->hot_add_disk) {
5932 		printk(KERN_WARNING
5933 			"%s: personality does not support diskops!\n",
5934 			mdname(mddev));
5935 		return -EINVAL;
5936 	}
5937 
5938 	rdev = md_import_device(dev, -1, 0);
5939 	if (IS_ERR(rdev)) {
5940 		printk(KERN_WARNING
5941 			"md: error, md_import_device() returned %ld\n",
5942 			PTR_ERR(rdev));
5943 		return -EINVAL;
5944 	}
5945 
5946 	if (mddev->persistent)
5947 		rdev->sb_start = calc_dev_sboffset(rdev);
5948 	else
5949 		rdev->sb_start = i_size_read(rdev->bdev->bd_inode) / 512;
5950 
5951 	rdev->sectors = rdev->sb_start;
5952 
5953 	if (test_bit(Faulty, &rdev->flags)) {
5954 		printk(KERN_WARNING
5955 			"md: can not hot-add faulty %s disk to %s!\n",
5956 			bdevname(rdev->bdev,b), mdname(mddev));
5957 		err = -EINVAL;
5958 		goto abort_export;
5959 	}
5960 	clear_bit(In_sync, &rdev->flags);
5961 	rdev->desc_nr = -1;
5962 	rdev->saved_raid_disk = -1;
5963 	err = bind_rdev_to_array(rdev, mddev);
5964 	if (err)
5965 		goto abort_export;
5966 
5967 	/*
5968 	 * The rest should better be atomic, we can have disk failures
5969 	 * noticed in interrupt contexts ...
5970 	 */
5971 
5972 	rdev->raid_disk = -1;
5973 
5974 	md_update_sb(mddev, 1);
5975 
5976 	/*
5977 	 * Kick recovery, maybe this spare has to be added to the
5978 	 * array immediately.
5979 	 */
5980 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
5981 	md_wakeup_thread(mddev->thread);
5982 	md_new_event(mddev);
5983 	return 0;
5984 
5985 abort_export:
5986 	export_rdev(rdev);
5987 	return err;
5988 }
5989 
5990 static int set_bitmap_file(struct mddev *mddev, int fd)
5991 {
5992 	int err;
5993 
5994 	if (mddev->pers) {
5995 		if (!mddev->pers->quiesce)
5996 			return -EBUSY;
5997 		if (mddev->recovery || mddev->sync_thread)
5998 			return -EBUSY;
5999 		/* we should be able to change the bitmap.. */
6000 	}
6001 
6002 
6003 	if (fd >= 0) {
6004 		if (mddev->bitmap)
6005 			return -EEXIST; /* cannot add when bitmap is present */
6006 		mddev->bitmap_info.file = fget(fd);
6007 
6008 		if (mddev->bitmap_info.file == NULL) {
6009 			printk(KERN_ERR "%s: error: failed to get bitmap file\n",
6010 			       mdname(mddev));
6011 			return -EBADF;
6012 		}
6013 
6014 		err = deny_bitmap_write_access(mddev->bitmap_info.file);
6015 		if (err) {
6016 			printk(KERN_ERR "%s: error: bitmap file is already in use\n",
6017 			       mdname(mddev));
6018 			fput(mddev->bitmap_info.file);
6019 			mddev->bitmap_info.file = NULL;
6020 			return err;
6021 		}
6022 		mddev->bitmap_info.offset = 0; /* file overrides offset */
6023 	} else if (mddev->bitmap == NULL)
6024 		return -ENOENT; /* cannot remove what isn't there */
6025 	err = 0;
6026 	if (mddev->pers) {
6027 		mddev->pers->quiesce(mddev, 1);
6028 		if (fd >= 0) {
6029 			err = bitmap_create(mddev);
6030 			if (!err)
6031 				err = bitmap_load(mddev);
6032 		}
6033 		if (fd < 0 || err) {
6034 			bitmap_destroy(mddev);
6035 			fd = -1; /* make sure to put the file */
6036 		}
6037 		mddev->pers->quiesce(mddev, 0);
6038 	}
6039 	if (fd < 0) {
6040 		if (mddev->bitmap_info.file) {
6041 			restore_bitmap_write_access(mddev->bitmap_info.file);
6042 			fput(mddev->bitmap_info.file);
6043 		}
6044 		mddev->bitmap_info.file = NULL;
6045 	}
6046 
6047 	return err;
6048 }
6049 
6050 /*
6051  * set_array_info is used two different ways
6052  * The original usage is when creating a new array.
6053  * In this usage, raid_disks is > 0 and it together with
6054  *  level, size, not_persistent,layout,chunksize determine the
6055  *  shape of the array.
6056  *  This will always create an array with a type-0.90.0 superblock.
6057  * The newer usage is when assembling an array.
6058  *  In this case raid_disks will be 0, and the major_version field is
6059  *  use to determine which style super-blocks are to be found on the devices.
6060  *  The minor and patch _version numbers are also kept incase the
6061  *  super_block handler wishes to interpret them.
6062  */
6063 static int set_array_info(struct mddev * mddev, mdu_array_info_t *info)
6064 {
6065 
6066 	if (info->raid_disks == 0) {
6067 		/* just setting version number for superblock loading */
6068 		if (info->major_version < 0 ||
6069 		    info->major_version >= ARRAY_SIZE(super_types) ||
6070 		    super_types[info->major_version].name == NULL) {
6071 			/* maybe try to auto-load a module? */
6072 			printk(KERN_INFO
6073 				"md: superblock version %d not known\n",
6074 				info->major_version);
6075 			return -EINVAL;
6076 		}
6077 		mddev->major_version = info->major_version;
6078 		mddev->minor_version = info->minor_version;
6079 		mddev->patch_version = info->patch_version;
6080 		mddev->persistent = !info->not_persistent;
6081 		/* ensure mddev_put doesn't delete this now that there
6082 		 * is some minimal configuration.
6083 		 */
6084 		mddev->ctime         = get_seconds();
6085 		return 0;
6086 	}
6087 	mddev->major_version = MD_MAJOR_VERSION;
6088 	mddev->minor_version = MD_MINOR_VERSION;
6089 	mddev->patch_version = MD_PATCHLEVEL_VERSION;
6090 	mddev->ctime         = get_seconds();
6091 
6092 	mddev->level         = info->level;
6093 	mddev->clevel[0]     = 0;
6094 	mddev->dev_sectors   = 2 * (sector_t)info->size;
6095 	mddev->raid_disks    = info->raid_disks;
6096 	/* don't set md_minor, it is determined by which /dev/md* was
6097 	 * openned
6098 	 */
6099 	if (info->state & (1<<MD_SB_CLEAN))
6100 		mddev->recovery_cp = MaxSector;
6101 	else
6102 		mddev->recovery_cp = 0;
6103 	mddev->persistent    = ! info->not_persistent;
6104 	mddev->external	     = 0;
6105 
6106 	mddev->layout        = info->layout;
6107 	mddev->chunk_sectors = info->chunk_size >> 9;
6108 
6109 	mddev->max_disks     = MD_SB_DISKS;
6110 
6111 	if (mddev->persistent)
6112 		mddev->flags         = 0;
6113 	set_bit(MD_CHANGE_DEVS, &mddev->flags);
6114 
6115 	mddev->bitmap_info.default_offset = MD_SB_BYTES >> 9;
6116 	mddev->bitmap_info.default_space = 64*2 - (MD_SB_BYTES >> 9);
6117 	mddev->bitmap_info.offset = 0;
6118 
6119 	mddev->reshape_position = MaxSector;
6120 
6121 	/*
6122 	 * Generate a 128 bit UUID
6123 	 */
6124 	get_random_bytes(mddev->uuid, 16);
6125 
6126 	mddev->new_level = mddev->level;
6127 	mddev->new_chunk_sectors = mddev->chunk_sectors;
6128 	mddev->new_layout = mddev->layout;
6129 	mddev->delta_disks = 0;
6130 	mddev->reshape_backwards = 0;
6131 
6132 	return 0;
6133 }
6134 
6135 void md_set_array_sectors(struct mddev *mddev, sector_t array_sectors)
6136 {
6137 	WARN(!mddev_is_locked(mddev), "%s: unlocked mddev!\n", __func__);
6138 
6139 	if (mddev->external_size)
6140 		return;
6141 
6142 	mddev->array_sectors = array_sectors;
6143 }
6144 EXPORT_SYMBOL(md_set_array_sectors);
6145 
6146 static int update_size(struct mddev *mddev, sector_t num_sectors)
6147 {
6148 	struct md_rdev *rdev;
6149 	int rv;
6150 	int fit = (num_sectors == 0);
6151 
6152 	if (mddev->pers->resize == NULL)
6153 		return -EINVAL;
6154 	/* The "num_sectors" is the number of sectors of each device that
6155 	 * is used.  This can only make sense for arrays with redundancy.
6156 	 * linear and raid0 always use whatever space is available. We can only
6157 	 * consider changing this number if no resync or reconstruction is
6158 	 * happening, and if the new size is acceptable. It must fit before the
6159 	 * sb_start or, if that is <data_offset, it must fit before the size
6160 	 * of each device.  If num_sectors is zero, we find the largest size
6161 	 * that fits.
6162 	 */
6163 	if (mddev->sync_thread)
6164 		return -EBUSY;
6165 
6166 	rdev_for_each(rdev, mddev) {
6167 		sector_t avail = rdev->sectors;
6168 
6169 		if (fit && (num_sectors == 0 || num_sectors > avail))
6170 			num_sectors = avail;
6171 		if (avail < num_sectors)
6172 			return -ENOSPC;
6173 	}
6174 	rv = mddev->pers->resize(mddev, num_sectors);
6175 	if (!rv)
6176 		revalidate_disk(mddev->gendisk);
6177 	return rv;
6178 }
6179 
6180 static int update_raid_disks(struct mddev *mddev, int raid_disks)
6181 {
6182 	int rv;
6183 	struct md_rdev *rdev;
6184 	/* change the number of raid disks */
6185 	if (mddev->pers->check_reshape == NULL)
6186 		return -EINVAL;
6187 	if (raid_disks <= 0 ||
6188 	    (mddev->max_disks && raid_disks >= mddev->max_disks))
6189 		return -EINVAL;
6190 	if (mddev->sync_thread || mddev->reshape_position != MaxSector)
6191 		return -EBUSY;
6192 
6193 	rdev_for_each(rdev, mddev) {
6194 		if (mddev->raid_disks < raid_disks &&
6195 		    rdev->data_offset < rdev->new_data_offset)
6196 			return -EINVAL;
6197 		if (mddev->raid_disks > raid_disks &&
6198 		    rdev->data_offset > rdev->new_data_offset)
6199 			return -EINVAL;
6200 	}
6201 
6202 	mddev->delta_disks = raid_disks - mddev->raid_disks;
6203 	if (mddev->delta_disks < 0)
6204 		mddev->reshape_backwards = 1;
6205 	else if (mddev->delta_disks > 0)
6206 		mddev->reshape_backwards = 0;
6207 
6208 	rv = mddev->pers->check_reshape(mddev);
6209 	if (rv < 0) {
6210 		mddev->delta_disks = 0;
6211 		mddev->reshape_backwards = 0;
6212 	}
6213 	return rv;
6214 }
6215 
6216 
6217 /*
6218  * update_array_info is used to change the configuration of an
6219  * on-line array.
6220  * The version, ctime,level,size,raid_disks,not_persistent, layout,chunk_size
6221  * fields in the info are checked against the array.
6222  * Any differences that cannot be handled will cause an error.
6223  * Normally, only one change can be managed at a time.
6224  */
6225 static int update_array_info(struct mddev *mddev, mdu_array_info_t *info)
6226 {
6227 	int rv = 0;
6228 	int cnt = 0;
6229 	int state = 0;
6230 
6231 	/* calculate expected state,ignoring low bits */
6232 	if (mddev->bitmap && mddev->bitmap_info.offset)
6233 		state |= (1 << MD_SB_BITMAP_PRESENT);
6234 
6235 	if (mddev->major_version != info->major_version ||
6236 	    mddev->minor_version != info->minor_version ||
6237 /*	    mddev->patch_version != info->patch_version || */
6238 	    mddev->ctime         != info->ctime         ||
6239 	    mddev->level         != info->level         ||
6240 /*	    mddev->layout        != info->layout        || */
6241 	    !mddev->persistent	 != info->not_persistent||
6242 	    mddev->chunk_sectors != info->chunk_size >> 9 ||
6243 	    /* ignore bottom 8 bits of state, and allow SB_BITMAP_PRESENT to change */
6244 	    ((state^info->state) & 0xfffffe00)
6245 		)
6246 		return -EINVAL;
6247 	/* Check there is only one change */
6248 	if (info->size >= 0 && mddev->dev_sectors / 2 != info->size)
6249 		cnt++;
6250 	if (mddev->raid_disks != info->raid_disks)
6251 		cnt++;
6252 	if (mddev->layout != info->layout)
6253 		cnt++;
6254 	if ((state ^ info->state) & (1<<MD_SB_BITMAP_PRESENT))
6255 		cnt++;
6256 	if (cnt == 0)
6257 		return 0;
6258 	if (cnt > 1)
6259 		return -EINVAL;
6260 
6261 	if (mddev->layout != info->layout) {
6262 		/* Change layout
6263 		 * we don't need to do anything at the md level, the
6264 		 * personality will take care of it all.
6265 		 */
6266 		if (mddev->pers->check_reshape == NULL)
6267 			return -EINVAL;
6268 		else {
6269 			mddev->new_layout = info->layout;
6270 			rv = mddev->pers->check_reshape(mddev);
6271 			if (rv)
6272 				mddev->new_layout = mddev->layout;
6273 			return rv;
6274 		}
6275 	}
6276 	if (info->size >= 0 && mddev->dev_sectors / 2 != info->size)
6277 		rv = update_size(mddev, (sector_t)info->size * 2);
6278 
6279 	if (mddev->raid_disks    != info->raid_disks)
6280 		rv = update_raid_disks(mddev, info->raid_disks);
6281 
6282 	if ((state ^ info->state) & (1<<MD_SB_BITMAP_PRESENT)) {
6283 		if (mddev->pers->quiesce == NULL)
6284 			return -EINVAL;
6285 		if (mddev->recovery || mddev->sync_thread)
6286 			return -EBUSY;
6287 		if (info->state & (1<<MD_SB_BITMAP_PRESENT)) {
6288 			/* add the bitmap */
6289 			if (mddev->bitmap)
6290 				return -EEXIST;
6291 			if (mddev->bitmap_info.default_offset == 0)
6292 				return -EINVAL;
6293 			mddev->bitmap_info.offset =
6294 				mddev->bitmap_info.default_offset;
6295 			mddev->bitmap_info.space =
6296 				mddev->bitmap_info.default_space;
6297 			mddev->pers->quiesce(mddev, 1);
6298 			rv = bitmap_create(mddev);
6299 			if (!rv)
6300 				rv = bitmap_load(mddev);
6301 			if (rv)
6302 				bitmap_destroy(mddev);
6303 			mddev->pers->quiesce(mddev, 0);
6304 		} else {
6305 			/* remove the bitmap */
6306 			if (!mddev->bitmap)
6307 				return -ENOENT;
6308 			if (mddev->bitmap->storage.file)
6309 				return -EINVAL;
6310 			mddev->pers->quiesce(mddev, 1);
6311 			bitmap_destroy(mddev);
6312 			mddev->pers->quiesce(mddev, 0);
6313 			mddev->bitmap_info.offset = 0;
6314 		}
6315 	}
6316 	md_update_sb(mddev, 1);
6317 	return rv;
6318 }
6319 
6320 static int set_disk_faulty(struct mddev *mddev, dev_t dev)
6321 {
6322 	struct md_rdev *rdev;
6323 
6324 	if (mddev->pers == NULL)
6325 		return -ENODEV;
6326 
6327 	rdev = find_rdev(mddev, dev);
6328 	if (!rdev)
6329 		return -ENODEV;
6330 
6331 	md_error(mddev, rdev);
6332 	if (!test_bit(Faulty, &rdev->flags))
6333 		return -EBUSY;
6334 	return 0;
6335 }
6336 
6337 /*
6338  * We have a problem here : there is no easy way to give a CHS
6339  * virtual geometry. We currently pretend that we have a 2 heads
6340  * 4 sectors (with a BIG number of cylinders...). This drives
6341  * dosfs just mad... ;-)
6342  */
6343 static int md_getgeo(struct block_device *bdev, struct hd_geometry *geo)
6344 {
6345 	struct mddev *mddev = bdev->bd_disk->private_data;
6346 
6347 	geo->heads = 2;
6348 	geo->sectors = 4;
6349 	geo->cylinders = mddev->array_sectors / 8;
6350 	return 0;
6351 }
6352 
6353 static int md_ioctl(struct block_device *bdev, fmode_t mode,
6354 			unsigned int cmd, unsigned long arg)
6355 {
6356 	int err = 0;
6357 	void __user *argp = (void __user *)arg;
6358 	struct mddev *mddev = NULL;
6359 	int ro;
6360 
6361 	switch (cmd) {
6362 	case RAID_VERSION:
6363 	case GET_ARRAY_INFO:
6364 	case GET_DISK_INFO:
6365 		break;
6366 	default:
6367 		if (!capable(CAP_SYS_ADMIN))
6368 			return -EACCES;
6369 	}
6370 
6371 	/*
6372 	 * Commands dealing with the RAID driver but not any
6373 	 * particular array:
6374 	 */
6375 	switch (cmd)
6376 	{
6377 		case RAID_VERSION:
6378 			err = get_version(argp);
6379 			goto done;
6380 
6381 		case PRINT_RAID_DEBUG:
6382 			err = 0;
6383 			md_print_devices();
6384 			goto done;
6385 
6386 #ifndef MODULE
6387 		case RAID_AUTORUN:
6388 			err = 0;
6389 			autostart_arrays(arg);
6390 			goto done;
6391 #endif
6392 		default:;
6393 	}
6394 
6395 	/*
6396 	 * Commands creating/starting a new array:
6397 	 */
6398 
6399 	mddev = bdev->bd_disk->private_data;
6400 
6401 	if (!mddev) {
6402 		BUG();
6403 		goto abort;
6404 	}
6405 
6406 	err = mddev_lock(mddev);
6407 	if (err) {
6408 		printk(KERN_INFO
6409 			"md: ioctl lock interrupted, reason %d, cmd %d\n",
6410 			err, cmd);
6411 		goto abort;
6412 	}
6413 
6414 	switch (cmd)
6415 	{
6416 		case SET_ARRAY_INFO:
6417 			{
6418 				mdu_array_info_t info;
6419 				if (!arg)
6420 					memset(&info, 0, sizeof(info));
6421 				else if (copy_from_user(&info, argp, sizeof(info))) {
6422 					err = -EFAULT;
6423 					goto abort_unlock;
6424 				}
6425 				if (mddev->pers) {
6426 					err = update_array_info(mddev, &info);
6427 					if (err) {
6428 						printk(KERN_WARNING "md: couldn't update"
6429 						       " array info. %d\n", err);
6430 						goto abort_unlock;
6431 					}
6432 					goto done_unlock;
6433 				}
6434 				if (!list_empty(&mddev->disks)) {
6435 					printk(KERN_WARNING
6436 					       "md: array %s already has disks!\n",
6437 					       mdname(mddev));
6438 					err = -EBUSY;
6439 					goto abort_unlock;
6440 				}
6441 				if (mddev->raid_disks) {
6442 					printk(KERN_WARNING
6443 					       "md: array %s already initialised!\n",
6444 					       mdname(mddev));
6445 					err = -EBUSY;
6446 					goto abort_unlock;
6447 				}
6448 				err = set_array_info(mddev, &info);
6449 				if (err) {
6450 					printk(KERN_WARNING "md: couldn't set"
6451 					       " array info. %d\n", err);
6452 					goto abort_unlock;
6453 				}
6454 			}
6455 			goto done_unlock;
6456 
6457 		default:;
6458 	}
6459 
6460 	/*
6461 	 * Commands querying/configuring an existing array:
6462 	 */
6463 	/* if we are not initialised yet, only ADD_NEW_DISK, STOP_ARRAY,
6464 	 * RUN_ARRAY, and GET_ and SET_BITMAP_FILE are allowed */
6465 	if ((!mddev->raid_disks && !mddev->external)
6466 	    && cmd != ADD_NEW_DISK && cmd != STOP_ARRAY
6467 	    && cmd != RUN_ARRAY && cmd != SET_BITMAP_FILE
6468 	    && cmd != GET_BITMAP_FILE) {
6469 		err = -ENODEV;
6470 		goto abort_unlock;
6471 	}
6472 
6473 	/*
6474 	 * Commands even a read-only array can execute:
6475 	 */
6476 	switch (cmd)
6477 	{
6478 		case GET_ARRAY_INFO:
6479 			err = get_array_info(mddev, argp);
6480 			goto done_unlock;
6481 
6482 		case GET_BITMAP_FILE:
6483 			err = get_bitmap_file(mddev, argp);
6484 			goto done_unlock;
6485 
6486 		case GET_DISK_INFO:
6487 			err = get_disk_info(mddev, argp);
6488 			goto done_unlock;
6489 
6490 		case RESTART_ARRAY_RW:
6491 			err = restart_array(mddev);
6492 			goto done_unlock;
6493 
6494 		case STOP_ARRAY:
6495 			err = do_md_stop(mddev, 0, bdev);
6496 			goto done_unlock;
6497 
6498 		case STOP_ARRAY_RO:
6499 			err = md_set_readonly(mddev, bdev);
6500 			goto done_unlock;
6501 
6502 		case BLKROSET:
6503 			if (get_user(ro, (int __user *)(arg))) {
6504 				err = -EFAULT;
6505 				goto done_unlock;
6506 			}
6507 			err = -EINVAL;
6508 
6509 			/* if the bdev is going readonly the value of mddev->ro
6510 			 * does not matter, no writes are coming
6511 			 */
6512 			if (ro)
6513 				goto done_unlock;
6514 
6515 			/* are we are already prepared for writes? */
6516 			if (mddev->ro != 1)
6517 				goto done_unlock;
6518 
6519 			/* transitioning to readauto need only happen for
6520 			 * arrays that call md_write_start
6521 			 */
6522 			if (mddev->pers) {
6523 				err = restart_array(mddev);
6524 				if (err == 0) {
6525 					mddev->ro = 2;
6526 					set_disk_ro(mddev->gendisk, 0);
6527 				}
6528 			}
6529 			goto done_unlock;
6530 	}
6531 
6532 	/*
6533 	 * The remaining ioctls are changing the state of the
6534 	 * superblock, so we do not allow them on read-only arrays.
6535 	 * However non-MD ioctls (e.g. get-size) will still come through
6536 	 * here and hit the 'default' below, so only disallow
6537 	 * 'md' ioctls, and switch to rw mode if started auto-readonly.
6538 	 */
6539 	if (_IOC_TYPE(cmd) == MD_MAJOR && mddev->ro && mddev->pers) {
6540 		if (mddev->ro == 2) {
6541 			mddev->ro = 0;
6542 			sysfs_notify_dirent_safe(mddev->sysfs_state);
6543 			set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
6544 			md_wakeup_thread(mddev->thread);
6545 		} else {
6546 			err = -EROFS;
6547 			goto abort_unlock;
6548 		}
6549 	}
6550 
6551 	switch (cmd)
6552 	{
6553 		case ADD_NEW_DISK:
6554 		{
6555 			mdu_disk_info_t info;
6556 			if (copy_from_user(&info, argp, sizeof(info)))
6557 				err = -EFAULT;
6558 			else
6559 				err = add_new_disk(mddev, &info);
6560 			goto done_unlock;
6561 		}
6562 
6563 		case HOT_REMOVE_DISK:
6564 			err = hot_remove_disk(mddev, new_decode_dev(arg));
6565 			goto done_unlock;
6566 
6567 		case HOT_ADD_DISK:
6568 			err = hot_add_disk(mddev, new_decode_dev(arg));
6569 			goto done_unlock;
6570 
6571 		case SET_DISK_FAULTY:
6572 			err = set_disk_faulty(mddev, new_decode_dev(arg));
6573 			goto done_unlock;
6574 
6575 		case RUN_ARRAY:
6576 			err = do_md_run(mddev);
6577 			goto done_unlock;
6578 
6579 		case SET_BITMAP_FILE:
6580 			err = set_bitmap_file(mddev, (int)arg);
6581 			goto done_unlock;
6582 
6583 		default:
6584 			err = -EINVAL;
6585 			goto abort_unlock;
6586 	}
6587 
6588 done_unlock:
6589 abort_unlock:
6590 	if (mddev->hold_active == UNTIL_IOCTL &&
6591 	    err != -EINVAL)
6592 		mddev->hold_active = 0;
6593 	mddev_unlock(mddev);
6594 
6595 	return err;
6596 done:
6597 	if (err)
6598 		MD_BUG();
6599 abort:
6600 	return err;
6601 }
6602 #ifdef CONFIG_COMPAT
6603 static int md_compat_ioctl(struct block_device *bdev, fmode_t mode,
6604 		    unsigned int cmd, unsigned long arg)
6605 {
6606 	switch (cmd) {
6607 	case HOT_REMOVE_DISK:
6608 	case HOT_ADD_DISK:
6609 	case SET_DISK_FAULTY:
6610 	case SET_BITMAP_FILE:
6611 		/* These take in integer arg, do not convert */
6612 		break;
6613 	default:
6614 		arg = (unsigned long)compat_ptr(arg);
6615 		break;
6616 	}
6617 
6618 	return md_ioctl(bdev, mode, cmd, arg);
6619 }
6620 #endif /* CONFIG_COMPAT */
6621 
6622 static int md_open(struct block_device *bdev, fmode_t mode)
6623 {
6624 	/*
6625 	 * Succeed if we can lock the mddev, which confirms that
6626 	 * it isn't being stopped right now.
6627 	 */
6628 	struct mddev *mddev = mddev_find(bdev->bd_dev);
6629 	int err;
6630 
6631 	if (!mddev)
6632 		return -ENODEV;
6633 
6634 	if (mddev->gendisk != bdev->bd_disk) {
6635 		/* we are racing with mddev_put which is discarding this
6636 		 * bd_disk.
6637 		 */
6638 		mddev_put(mddev);
6639 		/* Wait until bdev->bd_disk is definitely gone */
6640 		flush_workqueue(md_misc_wq);
6641 		/* Then retry the open from the top */
6642 		return -ERESTARTSYS;
6643 	}
6644 	BUG_ON(mddev != bdev->bd_disk->private_data);
6645 
6646 	if ((err = mutex_lock_interruptible(&mddev->open_mutex)))
6647 		goto out;
6648 
6649 	err = 0;
6650 	atomic_inc(&mddev->openers);
6651 	mutex_unlock(&mddev->open_mutex);
6652 
6653 	check_disk_change(bdev);
6654  out:
6655 	return err;
6656 }
6657 
6658 static int md_release(struct gendisk *disk, fmode_t mode)
6659 {
6660  	struct mddev *mddev = disk->private_data;
6661 
6662 	BUG_ON(!mddev);
6663 	atomic_dec(&mddev->openers);
6664 	mddev_put(mddev);
6665 
6666 	return 0;
6667 }
6668 
6669 static int md_media_changed(struct gendisk *disk)
6670 {
6671 	struct mddev *mddev = disk->private_data;
6672 
6673 	return mddev->changed;
6674 }
6675 
6676 static int md_revalidate(struct gendisk *disk)
6677 {
6678 	struct mddev *mddev = disk->private_data;
6679 
6680 	mddev->changed = 0;
6681 	return 0;
6682 }
6683 static const struct block_device_operations md_fops =
6684 {
6685 	.owner		= THIS_MODULE,
6686 	.open		= md_open,
6687 	.release	= md_release,
6688 	.ioctl		= md_ioctl,
6689 #ifdef CONFIG_COMPAT
6690 	.compat_ioctl	= md_compat_ioctl,
6691 #endif
6692 	.getgeo		= md_getgeo,
6693 	.media_changed  = md_media_changed,
6694 	.revalidate_disk= md_revalidate,
6695 };
6696 
6697 static int md_thread(void * arg)
6698 {
6699 	struct md_thread *thread = arg;
6700 
6701 	/*
6702 	 * md_thread is a 'system-thread', it's priority should be very
6703 	 * high. We avoid resource deadlocks individually in each
6704 	 * raid personality. (RAID5 does preallocation) We also use RR and
6705 	 * the very same RT priority as kswapd, thus we will never get
6706 	 * into a priority inversion deadlock.
6707 	 *
6708 	 * we definitely have to have equal or higher priority than
6709 	 * bdflush, otherwise bdflush will deadlock if there are too
6710 	 * many dirty RAID5 blocks.
6711 	 */
6712 
6713 	allow_signal(SIGKILL);
6714 	while (!kthread_should_stop()) {
6715 
6716 		/* We need to wait INTERRUPTIBLE so that
6717 		 * we don't add to the load-average.
6718 		 * That means we need to be sure no signals are
6719 		 * pending
6720 		 */
6721 		if (signal_pending(current))
6722 			flush_signals(current);
6723 
6724 		wait_event_interruptible_timeout
6725 			(thread->wqueue,
6726 			 test_bit(THREAD_WAKEUP, &thread->flags)
6727 			 || kthread_should_stop(),
6728 			 thread->timeout);
6729 
6730 		clear_bit(THREAD_WAKEUP, &thread->flags);
6731 		if (!kthread_should_stop())
6732 			thread->run(thread->mddev);
6733 	}
6734 
6735 	return 0;
6736 }
6737 
6738 void md_wakeup_thread(struct md_thread *thread)
6739 {
6740 	if (thread) {
6741 		pr_debug("md: waking up MD thread %s.\n", thread->tsk->comm);
6742 		set_bit(THREAD_WAKEUP, &thread->flags);
6743 		wake_up(&thread->wqueue);
6744 	}
6745 }
6746 
6747 struct md_thread *md_register_thread(void (*run) (struct mddev *), struct mddev *mddev,
6748 				 const char *name)
6749 {
6750 	struct md_thread *thread;
6751 
6752 	thread = kzalloc(sizeof(struct md_thread), GFP_KERNEL);
6753 	if (!thread)
6754 		return NULL;
6755 
6756 	init_waitqueue_head(&thread->wqueue);
6757 
6758 	thread->run = run;
6759 	thread->mddev = mddev;
6760 	thread->timeout = MAX_SCHEDULE_TIMEOUT;
6761 	thread->tsk = kthread_run(md_thread, thread,
6762 				  "%s_%s",
6763 				  mdname(thread->mddev),
6764 				  name);
6765 	if (IS_ERR(thread->tsk)) {
6766 		kfree(thread);
6767 		return NULL;
6768 	}
6769 	return thread;
6770 }
6771 
6772 void md_unregister_thread(struct md_thread **threadp)
6773 {
6774 	struct md_thread *thread = *threadp;
6775 	if (!thread)
6776 		return;
6777 	pr_debug("interrupting MD-thread pid %d\n", task_pid_nr(thread->tsk));
6778 	/* Locking ensures that mddev_unlock does not wake_up a
6779 	 * non-existent thread
6780 	 */
6781 	spin_lock(&pers_lock);
6782 	*threadp = NULL;
6783 	spin_unlock(&pers_lock);
6784 
6785 	kthread_stop(thread->tsk);
6786 	kfree(thread);
6787 }
6788 
6789 void md_error(struct mddev *mddev, struct md_rdev *rdev)
6790 {
6791 	if (!mddev) {
6792 		MD_BUG();
6793 		return;
6794 	}
6795 
6796 	if (!rdev || test_bit(Faulty, &rdev->flags))
6797 		return;
6798 
6799 	if (!mddev->pers || !mddev->pers->error_handler)
6800 		return;
6801 	mddev->pers->error_handler(mddev,rdev);
6802 	if (mddev->degraded)
6803 		set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
6804 	sysfs_notify_dirent_safe(rdev->sysfs_state);
6805 	set_bit(MD_RECOVERY_INTR, &mddev->recovery);
6806 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
6807 	md_wakeup_thread(mddev->thread);
6808 	if (mddev->event_work.func)
6809 		queue_work(md_misc_wq, &mddev->event_work);
6810 	md_new_event_inintr(mddev);
6811 }
6812 
6813 /* seq_file implementation /proc/mdstat */
6814 
6815 static void status_unused(struct seq_file *seq)
6816 {
6817 	int i = 0;
6818 	struct md_rdev *rdev;
6819 
6820 	seq_printf(seq, "unused devices: ");
6821 
6822 	list_for_each_entry(rdev, &pending_raid_disks, same_set) {
6823 		char b[BDEVNAME_SIZE];
6824 		i++;
6825 		seq_printf(seq, "%s ",
6826 			      bdevname(rdev->bdev,b));
6827 	}
6828 	if (!i)
6829 		seq_printf(seq, "<none>");
6830 
6831 	seq_printf(seq, "\n");
6832 }
6833 
6834 
6835 static void status_resync(struct seq_file *seq, struct mddev * mddev)
6836 {
6837 	sector_t max_sectors, resync, res;
6838 	unsigned long dt, db;
6839 	sector_t rt;
6840 	int scale;
6841 	unsigned int per_milli;
6842 
6843 	resync = mddev->curr_resync - atomic_read(&mddev->recovery_active);
6844 
6845 	if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) ||
6846 	    test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
6847 		max_sectors = mddev->resync_max_sectors;
6848 	else
6849 		max_sectors = mddev->dev_sectors;
6850 
6851 	/*
6852 	 * Should not happen.
6853 	 */
6854 	if (!max_sectors) {
6855 		MD_BUG();
6856 		return;
6857 	}
6858 	/* Pick 'scale' such that (resync>>scale)*1000 will fit
6859 	 * in a sector_t, and (max_sectors>>scale) will fit in a
6860 	 * u32, as those are the requirements for sector_div.
6861 	 * Thus 'scale' must be at least 10
6862 	 */
6863 	scale = 10;
6864 	if (sizeof(sector_t) > sizeof(unsigned long)) {
6865 		while ( max_sectors/2 > (1ULL<<(scale+32)))
6866 			scale++;
6867 	}
6868 	res = (resync>>scale)*1000;
6869 	sector_div(res, (u32)((max_sectors>>scale)+1));
6870 
6871 	per_milli = res;
6872 	{
6873 		int i, x = per_milli/50, y = 20-x;
6874 		seq_printf(seq, "[");
6875 		for (i = 0; i < x; i++)
6876 			seq_printf(seq, "=");
6877 		seq_printf(seq, ">");
6878 		for (i = 0; i < y; i++)
6879 			seq_printf(seq, ".");
6880 		seq_printf(seq, "] ");
6881 	}
6882 	seq_printf(seq, " %s =%3u.%u%% (%llu/%llu)",
6883 		   (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)?
6884 		    "reshape" :
6885 		    (test_bit(MD_RECOVERY_CHECK, &mddev->recovery)?
6886 		     "check" :
6887 		     (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) ?
6888 		      "resync" : "recovery"))),
6889 		   per_milli/10, per_milli % 10,
6890 		   (unsigned long long) resync/2,
6891 		   (unsigned long long) max_sectors/2);
6892 
6893 	/*
6894 	 * dt: time from mark until now
6895 	 * db: blocks written from mark until now
6896 	 * rt: remaining time
6897 	 *
6898 	 * rt is a sector_t, so could be 32bit or 64bit.
6899 	 * So we divide before multiply in case it is 32bit and close
6900 	 * to the limit.
6901 	 * We scale the divisor (db) by 32 to avoid losing precision
6902 	 * near the end of resync when the number of remaining sectors
6903 	 * is close to 'db'.
6904 	 * We then divide rt by 32 after multiplying by db to compensate.
6905 	 * The '+1' avoids division by zero if db is very small.
6906 	 */
6907 	dt = ((jiffies - mddev->resync_mark) / HZ);
6908 	if (!dt) dt++;
6909 	db = (mddev->curr_mark_cnt - atomic_read(&mddev->recovery_active))
6910 		- mddev->resync_mark_cnt;
6911 
6912 	rt = max_sectors - resync;    /* number of remaining sectors */
6913 	sector_div(rt, db/32+1);
6914 	rt *= dt;
6915 	rt >>= 5;
6916 
6917 	seq_printf(seq, " finish=%lu.%lumin", (unsigned long)rt / 60,
6918 		   ((unsigned long)rt % 60)/6);
6919 
6920 	seq_printf(seq, " speed=%ldK/sec", db/2/dt);
6921 }
6922 
6923 static void *md_seq_start(struct seq_file *seq, loff_t *pos)
6924 {
6925 	struct list_head *tmp;
6926 	loff_t l = *pos;
6927 	struct mddev *mddev;
6928 
6929 	if (l >= 0x10000)
6930 		return NULL;
6931 	if (!l--)
6932 		/* header */
6933 		return (void*)1;
6934 
6935 	spin_lock(&all_mddevs_lock);
6936 	list_for_each(tmp,&all_mddevs)
6937 		if (!l--) {
6938 			mddev = list_entry(tmp, struct mddev, all_mddevs);
6939 			mddev_get(mddev);
6940 			spin_unlock(&all_mddevs_lock);
6941 			return mddev;
6942 		}
6943 	spin_unlock(&all_mddevs_lock);
6944 	if (!l--)
6945 		return (void*)2;/* tail */
6946 	return NULL;
6947 }
6948 
6949 static void *md_seq_next(struct seq_file *seq, void *v, loff_t *pos)
6950 {
6951 	struct list_head *tmp;
6952 	struct mddev *next_mddev, *mddev = v;
6953 
6954 	++*pos;
6955 	if (v == (void*)2)
6956 		return NULL;
6957 
6958 	spin_lock(&all_mddevs_lock);
6959 	if (v == (void*)1)
6960 		tmp = all_mddevs.next;
6961 	else
6962 		tmp = mddev->all_mddevs.next;
6963 	if (tmp != &all_mddevs)
6964 		next_mddev = mddev_get(list_entry(tmp,struct mddev,all_mddevs));
6965 	else {
6966 		next_mddev = (void*)2;
6967 		*pos = 0x10000;
6968 	}
6969 	spin_unlock(&all_mddevs_lock);
6970 
6971 	if (v != (void*)1)
6972 		mddev_put(mddev);
6973 	return next_mddev;
6974 
6975 }
6976 
6977 static void md_seq_stop(struct seq_file *seq, void *v)
6978 {
6979 	struct mddev *mddev = v;
6980 
6981 	if (mddev && v != (void*)1 && v != (void*)2)
6982 		mddev_put(mddev);
6983 }
6984 
6985 static int md_seq_show(struct seq_file *seq, void *v)
6986 {
6987 	struct mddev *mddev = v;
6988 	sector_t sectors;
6989 	struct md_rdev *rdev;
6990 
6991 	if (v == (void*)1) {
6992 		struct md_personality *pers;
6993 		seq_printf(seq, "Personalities : ");
6994 		spin_lock(&pers_lock);
6995 		list_for_each_entry(pers, &pers_list, list)
6996 			seq_printf(seq, "[%s] ", pers->name);
6997 
6998 		spin_unlock(&pers_lock);
6999 		seq_printf(seq, "\n");
7000 		seq->poll_event = atomic_read(&md_event_count);
7001 		return 0;
7002 	}
7003 	if (v == (void*)2) {
7004 		status_unused(seq);
7005 		return 0;
7006 	}
7007 
7008 	if (mddev_lock(mddev) < 0)
7009 		return -EINTR;
7010 
7011 	if (mddev->pers || mddev->raid_disks || !list_empty(&mddev->disks)) {
7012 		seq_printf(seq, "%s : %sactive", mdname(mddev),
7013 						mddev->pers ? "" : "in");
7014 		if (mddev->pers) {
7015 			if (mddev->ro==1)
7016 				seq_printf(seq, " (read-only)");
7017 			if (mddev->ro==2)
7018 				seq_printf(seq, " (auto-read-only)");
7019 			seq_printf(seq, " %s", mddev->pers->name);
7020 		}
7021 
7022 		sectors = 0;
7023 		rdev_for_each(rdev, mddev) {
7024 			char b[BDEVNAME_SIZE];
7025 			seq_printf(seq, " %s[%d]",
7026 				bdevname(rdev->bdev,b), rdev->desc_nr);
7027 			if (test_bit(WriteMostly, &rdev->flags))
7028 				seq_printf(seq, "(W)");
7029 			if (test_bit(Faulty, &rdev->flags)) {
7030 				seq_printf(seq, "(F)");
7031 				continue;
7032 			}
7033 			if (rdev->raid_disk < 0)
7034 				seq_printf(seq, "(S)"); /* spare */
7035 			if (test_bit(Replacement, &rdev->flags))
7036 				seq_printf(seq, "(R)");
7037 			sectors += rdev->sectors;
7038 		}
7039 
7040 		if (!list_empty(&mddev->disks)) {
7041 			if (mddev->pers)
7042 				seq_printf(seq, "\n      %llu blocks",
7043 					   (unsigned long long)
7044 					   mddev->array_sectors / 2);
7045 			else
7046 				seq_printf(seq, "\n      %llu blocks",
7047 					   (unsigned long long)sectors / 2);
7048 		}
7049 		if (mddev->persistent) {
7050 			if (mddev->major_version != 0 ||
7051 			    mddev->minor_version != 90) {
7052 				seq_printf(seq," super %d.%d",
7053 					   mddev->major_version,
7054 					   mddev->minor_version);
7055 			}
7056 		} else if (mddev->external)
7057 			seq_printf(seq, " super external:%s",
7058 				   mddev->metadata_type);
7059 		else
7060 			seq_printf(seq, " super non-persistent");
7061 
7062 		if (mddev->pers) {
7063 			mddev->pers->status(seq, mddev);
7064 	 		seq_printf(seq, "\n      ");
7065 			if (mddev->pers->sync_request) {
7066 				if (mddev->curr_resync > 2) {
7067 					status_resync(seq, mddev);
7068 					seq_printf(seq, "\n      ");
7069 				} else if (mddev->curr_resync == 1 || mddev->curr_resync == 2)
7070 					seq_printf(seq, "\tresync=DELAYED\n      ");
7071 				else if (mddev->recovery_cp < MaxSector)
7072 					seq_printf(seq, "\tresync=PENDING\n      ");
7073 			}
7074 		} else
7075 			seq_printf(seq, "\n       ");
7076 
7077 		bitmap_status(seq, mddev->bitmap);
7078 
7079 		seq_printf(seq, "\n");
7080 	}
7081 	mddev_unlock(mddev);
7082 
7083 	return 0;
7084 }
7085 
7086 static const struct seq_operations md_seq_ops = {
7087 	.start  = md_seq_start,
7088 	.next   = md_seq_next,
7089 	.stop   = md_seq_stop,
7090 	.show   = md_seq_show,
7091 };
7092 
7093 static int md_seq_open(struct inode *inode, struct file *file)
7094 {
7095 	struct seq_file *seq;
7096 	int error;
7097 
7098 	error = seq_open(file, &md_seq_ops);
7099 	if (error)
7100 		return error;
7101 
7102 	seq = file->private_data;
7103 	seq->poll_event = atomic_read(&md_event_count);
7104 	return error;
7105 }
7106 
7107 static unsigned int mdstat_poll(struct file *filp, poll_table *wait)
7108 {
7109 	struct seq_file *seq = filp->private_data;
7110 	int mask;
7111 
7112 	poll_wait(filp, &md_event_waiters, wait);
7113 
7114 	/* always allow read */
7115 	mask = POLLIN | POLLRDNORM;
7116 
7117 	if (seq->poll_event != atomic_read(&md_event_count))
7118 		mask |= POLLERR | POLLPRI;
7119 	return mask;
7120 }
7121 
7122 static const struct file_operations md_seq_fops = {
7123 	.owner		= THIS_MODULE,
7124 	.open           = md_seq_open,
7125 	.read           = seq_read,
7126 	.llseek         = seq_lseek,
7127 	.release	= seq_release_private,
7128 	.poll		= mdstat_poll,
7129 };
7130 
7131 int register_md_personality(struct md_personality *p)
7132 {
7133 	spin_lock(&pers_lock);
7134 	list_add_tail(&p->list, &pers_list);
7135 	printk(KERN_INFO "md: %s personality registered for level %d\n", p->name, p->level);
7136 	spin_unlock(&pers_lock);
7137 	return 0;
7138 }
7139 
7140 int unregister_md_personality(struct md_personality *p)
7141 {
7142 	printk(KERN_INFO "md: %s personality unregistered\n", p->name);
7143 	spin_lock(&pers_lock);
7144 	list_del_init(&p->list);
7145 	spin_unlock(&pers_lock);
7146 	return 0;
7147 }
7148 
7149 static int is_mddev_idle(struct mddev *mddev, int init)
7150 {
7151 	struct md_rdev * rdev;
7152 	int idle;
7153 	int curr_events;
7154 
7155 	idle = 1;
7156 	rcu_read_lock();
7157 	rdev_for_each_rcu(rdev, mddev) {
7158 		struct gendisk *disk = rdev->bdev->bd_contains->bd_disk;
7159 		curr_events = (int)part_stat_read(&disk->part0, sectors[0]) +
7160 			      (int)part_stat_read(&disk->part0, sectors[1]) -
7161 			      atomic_read(&disk->sync_io);
7162 		/* sync IO will cause sync_io to increase before the disk_stats
7163 		 * as sync_io is counted when a request starts, and
7164 		 * disk_stats is counted when it completes.
7165 		 * So resync activity will cause curr_events to be smaller than
7166 		 * when there was no such activity.
7167 		 * non-sync IO will cause disk_stat to increase without
7168 		 * increasing sync_io so curr_events will (eventually)
7169 		 * be larger than it was before.  Once it becomes
7170 		 * substantially larger, the test below will cause
7171 		 * the array to appear non-idle, and resync will slow
7172 		 * down.
7173 		 * If there is a lot of outstanding resync activity when
7174 		 * we set last_event to curr_events, then all that activity
7175 		 * completing might cause the array to appear non-idle
7176 		 * and resync will be slowed down even though there might
7177 		 * not have been non-resync activity.  This will only
7178 		 * happen once though.  'last_events' will soon reflect
7179 		 * the state where there is little or no outstanding
7180 		 * resync requests, and further resync activity will
7181 		 * always make curr_events less than last_events.
7182 		 *
7183 		 */
7184 		if (init || curr_events - rdev->last_events > 64) {
7185 			rdev->last_events = curr_events;
7186 			idle = 0;
7187 		}
7188 	}
7189 	rcu_read_unlock();
7190 	return idle;
7191 }
7192 
7193 void md_done_sync(struct mddev *mddev, int blocks, int ok)
7194 {
7195 	/* another "blocks" (512byte) blocks have been synced */
7196 	atomic_sub(blocks, &mddev->recovery_active);
7197 	wake_up(&mddev->recovery_wait);
7198 	if (!ok) {
7199 		set_bit(MD_RECOVERY_INTR, &mddev->recovery);
7200 		md_wakeup_thread(mddev->thread);
7201 		// stop recovery, signal do_sync ....
7202 	}
7203 }
7204 
7205 
7206 /* md_write_start(mddev, bi)
7207  * If we need to update some array metadata (e.g. 'active' flag
7208  * in superblock) before writing, schedule a superblock update
7209  * and wait for it to complete.
7210  */
7211 void md_write_start(struct mddev *mddev, struct bio *bi)
7212 {
7213 	int did_change = 0;
7214 	if (bio_data_dir(bi) != WRITE)
7215 		return;
7216 
7217 	BUG_ON(mddev->ro == 1);
7218 	if (mddev->ro == 2) {
7219 		/* need to switch to read/write */
7220 		mddev->ro = 0;
7221 		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
7222 		md_wakeup_thread(mddev->thread);
7223 		md_wakeup_thread(mddev->sync_thread);
7224 		did_change = 1;
7225 	}
7226 	atomic_inc(&mddev->writes_pending);
7227 	if (mddev->safemode == 1)
7228 		mddev->safemode = 0;
7229 	if (mddev->in_sync) {
7230 		spin_lock_irq(&mddev->write_lock);
7231 		if (mddev->in_sync) {
7232 			mddev->in_sync = 0;
7233 			set_bit(MD_CHANGE_CLEAN, &mddev->flags);
7234 			set_bit(MD_CHANGE_PENDING, &mddev->flags);
7235 			md_wakeup_thread(mddev->thread);
7236 			did_change = 1;
7237 		}
7238 		spin_unlock_irq(&mddev->write_lock);
7239 	}
7240 	if (did_change)
7241 		sysfs_notify_dirent_safe(mddev->sysfs_state);
7242 	wait_event(mddev->sb_wait,
7243 		   !test_bit(MD_CHANGE_PENDING, &mddev->flags));
7244 }
7245 
7246 void md_write_end(struct mddev *mddev)
7247 {
7248 	if (atomic_dec_and_test(&mddev->writes_pending)) {
7249 		if (mddev->safemode == 2)
7250 			md_wakeup_thread(mddev->thread);
7251 		else if (mddev->safemode_delay)
7252 			mod_timer(&mddev->safemode_timer, jiffies + mddev->safemode_delay);
7253 	}
7254 }
7255 
7256 /* md_allow_write(mddev)
7257  * Calling this ensures that the array is marked 'active' so that writes
7258  * may proceed without blocking.  It is important to call this before
7259  * attempting a GFP_KERNEL allocation while holding the mddev lock.
7260  * Must be called with mddev_lock held.
7261  *
7262  * In the ->external case MD_CHANGE_CLEAN can not be cleared until mddev->lock
7263  * is dropped, so return -EAGAIN after notifying userspace.
7264  */
7265 int md_allow_write(struct mddev *mddev)
7266 {
7267 	if (!mddev->pers)
7268 		return 0;
7269 	if (mddev->ro)
7270 		return 0;
7271 	if (!mddev->pers->sync_request)
7272 		return 0;
7273 
7274 	spin_lock_irq(&mddev->write_lock);
7275 	if (mddev->in_sync) {
7276 		mddev->in_sync = 0;
7277 		set_bit(MD_CHANGE_CLEAN, &mddev->flags);
7278 		set_bit(MD_CHANGE_PENDING, &mddev->flags);
7279 		if (mddev->safemode_delay &&
7280 		    mddev->safemode == 0)
7281 			mddev->safemode = 1;
7282 		spin_unlock_irq(&mddev->write_lock);
7283 		md_update_sb(mddev, 0);
7284 		sysfs_notify_dirent_safe(mddev->sysfs_state);
7285 	} else
7286 		spin_unlock_irq(&mddev->write_lock);
7287 
7288 	if (test_bit(MD_CHANGE_PENDING, &mddev->flags))
7289 		return -EAGAIN;
7290 	else
7291 		return 0;
7292 }
7293 EXPORT_SYMBOL_GPL(md_allow_write);
7294 
7295 #define SYNC_MARKS	10
7296 #define	SYNC_MARK_STEP	(3*HZ)
7297 void md_do_sync(struct mddev *mddev)
7298 {
7299 	struct mddev *mddev2;
7300 	unsigned int currspeed = 0,
7301 		 window;
7302 	sector_t max_sectors,j, io_sectors;
7303 	unsigned long mark[SYNC_MARKS];
7304 	sector_t mark_cnt[SYNC_MARKS];
7305 	int last_mark,m;
7306 	struct list_head *tmp;
7307 	sector_t last_check;
7308 	int skipped = 0;
7309 	struct md_rdev *rdev;
7310 	char *desc;
7311 	struct blk_plug plug;
7312 
7313 	/* just incase thread restarts... */
7314 	if (test_bit(MD_RECOVERY_DONE, &mddev->recovery))
7315 		return;
7316 	if (mddev->ro) /* never try to sync a read-only array */
7317 		return;
7318 
7319 	if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
7320 		if (test_bit(MD_RECOVERY_CHECK, &mddev->recovery))
7321 			desc = "data-check";
7322 		else if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
7323 			desc = "requested-resync";
7324 		else
7325 			desc = "resync";
7326 	} else if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
7327 		desc = "reshape";
7328 	else
7329 		desc = "recovery";
7330 
7331 	/* we overload curr_resync somewhat here.
7332 	 * 0 == not engaged in resync at all
7333 	 * 2 == checking that there is no conflict with another sync
7334 	 * 1 == like 2, but have yielded to allow conflicting resync to
7335 	 *		commense
7336 	 * other == active in resync - this many blocks
7337 	 *
7338 	 * Before starting a resync we must have set curr_resync to
7339 	 * 2, and then checked that every "conflicting" array has curr_resync
7340 	 * less than ours.  When we find one that is the same or higher
7341 	 * we wait on resync_wait.  To avoid deadlock, we reduce curr_resync
7342 	 * to 1 if we choose to yield (based arbitrarily on address of mddev structure).
7343 	 * This will mean we have to start checking from the beginning again.
7344 	 *
7345 	 */
7346 
7347 	do {
7348 		mddev->curr_resync = 2;
7349 
7350 	try_again:
7351 		if (kthread_should_stop())
7352 			set_bit(MD_RECOVERY_INTR, &mddev->recovery);
7353 
7354 		if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
7355 			goto skip;
7356 		for_each_mddev(mddev2, tmp) {
7357 			if (mddev2 == mddev)
7358 				continue;
7359 			if (!mddev->parallel_resync
7360 			&&  mddev2->curr_resync
7361 			&&  match_mddev_units(mddev, mddev2)) {
7362 				DEFINE_WAIT(wq);
7363 				if (mddev < mddev2 && mddev->curr_resync == 2) {
7364 					/* arbitrarily yield */
7365 					mddev->curr_resync = 1;
7366 					wake_up(&resync_wait);
7367 				}
7368 				if (mddev > mddev2 && mddev->curr_resync == 1)
7369 					/* no need to wait here, we can wait the next
7370 					 * time 'round when curr_resync == 2
7371 					 */
7372 					continue;
7373 				/* We need to wait 'interruptible' so as not to
7374 				 * contribute to the load average, and not to
7375 				 * be caught by 'softlockup'
7376 				 */
7377 				prepare_to_wait(&resync_wait, &wq, TASK_INTERRUPTIBLE);
7378 				if (!kthread_should_stop() &&
7379 				    mddev2->curr_resync >= mddev->curr_resync) {
7380 					printk(KERN_INFO "md: delaying %s of %s"
7381 					       " until %s has finished (they"
7382 					       " share one or more physical units)\n",
7383 					       desc, mdname(mddev), mdname(mddev2));
7384 					mddev_put(mddev2);
7385 					if (signal_pending(current))
7386 						flush_signals(current);
7387 					schedule();
7388 					finish_wait(&resync_wait, &wq);
7389 					goto try_again;
7390 				}
7391 				finish_wait(&resync_wait, &wq);
7392 			}
7393 		}
7394 	} while (mddev->curr_resync < 2);
7395 
7396 	j = 0;
7397 	if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
7398 		/* resync follows the size requested by the personality,
7399 		 * which defaults to physical size, but can be virtual size
7400 		 */
7401 		max_sectors = mddev->resync_max_sectors;
7402 		mddev->resync_mismatches = 0;
7403 		/* we don't use the checkpoint if there's a bitmap */
7404 		if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
7405 			j = mddev->resync_min;
7406 		else if (!mddev->bitmap)
7407 			j = mddev->recovery_cp;
7408 
7409 	} else if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
7410 		max_sectors = mddev->resync_max_sectors;
7411 	else {
7412 		/* recovery follows the physical size of devices */
7413 		max_sectors = mddev->dev_sectors;
7414 		j = MaxSector;
7415 		rcu_read_lock();
7416 		rdev_for_each_rcu(rdev, mddev)
7417 			if (rdev->raid_disk >= 0 &&
7418 			    !test_bit(Faulty, &rdev->flags) &&
7419 			    !test_bit(In_sync, &rdev->flags) &&
7420 			    rdev->recovery_offset < j)
7421 				j = rdev->recovery_offset;
7422 		rcu_read_unlock();
7423 	}
7424 
7425 	printk(KERN_INFO "md: %s of RAID array %s\n", desc, mdname(mddev));
7426 	printk(KERN_INFO "md: minimum _guaranteed_  speed:"
7427 		" %d KB/sec/disk.\n", speed_min(mddev));
7428 	printk(KERN_INFO "md: using maximum available idle IO bandwidth "
7429 	       "(but not more than %d KB/sec) for %s.\n",
7430 	       speed_max(mddev), desc);
7431 
7432 	is_mddev_idle(mddev, 1); /* this initializes IO event counters */
7433 
7434 	io_sectors = 0;
7435 	for (m = 0; m < SYNC_MARKS; m++) {
7436 		mark[m] = jiffies;
7437 		mark_cnt[m] = io_sectors;
7438 	}
7439 	last_mark = 0;
7440 	mddev->resync_mark = mark[last_mark];
7441 	mddev->resync_mark_cnt = mark_cnt[last_mark];
7442 
7443 	/*
7444 	 * Tune reconstruction:
7445 	 */
7446 	window = 32*(PAGE_SIZE/512);
7447 	printk(KERN_INFO "md: using %dk window, over a total of %lluk.\n",
7448 		window/2, (unsigned long long)max_sectors/2);
7449 
7450 	atomic_set(&mddev->recovery_active, 0);
7451 	last_check = 0;
7452 
7453 	if (j>2) {
7454 		printk(KERN_INFO
7455 		       "md: resuming %s of %s from checkpoint.\n",
7456 		       desc, mdname(mddev));
7457 		mddev->curr_resync = j;
7458 	}
7459 	mddev->curr_resync_completed = j;
7460 
7461 	blk_start_plug(&plug);
7462 	while (j < max_sectors) {
7463 		sector_t sectors;
7464 
7465 		skipped = 0;
7466 
7467 		if (!test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
7468 		    ((mddev->curr_resync > mddev->curr_resync_completed &&
7469 		      (mddev->curr_resync - mddev->curr_resync_completed)
7470 		      > (max_sectors >> 4)) ||
7471 		     (j - mddev->curr_resync_completed)*2
7472 		     >= mddev->resync_max - mddev->curr_resync_completed
7473 			    )) {
7474 			/* time to update curr_resync_completed */
7475 			wait_event(mddev->recovery_wait,
7476 				   atomic_read(&mddev->recovery_active) == 0);
7477 			mddev->curr_resync_completed = j;
7478 			set_bit(MD_CHANGE_CLEAN, &mddev->flags);
7479 			sysfs_notify(&mddev->kobj, NULL, "sync_completed");
7480 		}
7481 
7482 		while (j >= mddev->resync_max && !kthread_should_stop()) {
7483 			/* As this condition is controlled by user-space,
7484 			 * we can block indefinitely, so use '_interruptible'
7485 			 * to avoid triggering warnings.
7486 			 */
7487 			flush_signals(current); /* just in case */
7488 			wait_event_interruptible(mddev->recovery_wait,
7489 						 mddev->resync_max > j
7490 						 || kthread_should_stop());
7491 		}
7492 
7493 		if (kthread_should_stop())
7494 			goto interrupted;
7495 
7496 		sectors = mddev->pers->sync_request(mddev, j, &skipped,
7497 						  currspeed < speed_min(mddev));
7498 		if (sectors == 0) {
7499 			set_bit(MD_RECOVERY_INTR, &mddev->recovery);
7500 			goto out;
7501 		}
7502 
7503 		if (!skipped) { /* actual IO requested */
7504 			io_sectors += sectors;
7505 			atomic_add(sectors, &mddev->recovery_active);
7506 		}
7507 
7508 		if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
7509 			break;
7510 
7511 		j += sectors;
7512 		if (j>1) mddev->curr_resync = j;
7513 		mddev->curr_mark_cnt = io_sectors;
7514 		if (last_check == 0)
7515 			/* this is the earliest that rebuild will be
7516 			 * visible in /proc/mdstat
7517 			 */
7518 			md_new_event(mddev);
7519 
7520 		if (last_check + window > io_sectors || j == max_sectors)
7521 			continue;
7522 
7523 		last_check = io_sectors;
7524 	repeat:
7525 		if (time_after_eq(jiffies, mark[last_mark] + SYNC_MARK_STEP )) {
7526 			/* step marks */
7527 			int next = (last_mark+1) % SYNC_MARKS;
7528 
7529 			mddev->resync_mark = mark[next];
7530 			mddev->resync_mark_cnt = mark_cnt[next];
7531 			mark[next] = jiffies;
7532 			mark_cnt[next] = io_sectors - atomic_read(&mddev->recovery_active);
7533 			last_mark = next;
7534 		}
7535 
7536 
7537 		if (kthread_should_stop())
7538 			goto interrupted;
7539 
7540 
7541 		/*
7542 		 * this loop exits only if either when we are slower than
7543 		 * the 'hard' speed limit, or the system was IO-idle for
7544 		 * a jiffy.
7545 		 * the system might be non-idle CPU-wise, but we only care
7546 		 * about not overloading the IO subsystem. (things like an
7547 		 * e2fsck being done on the RAID array should execute fast)
7548 		 */
7549 		cond_resched();
7550 
7551 		currspeed = ((unsigned long)(io_sectors-mddev->resync_mark_cnt))/2
7552 			/((jiffies-mddev->resync_mark)/HZ +1) +1;
7553 
7554 		if (currspeed > speed_min(mddev)) {
7555 			if ((currspeed > speed_max(mddev)) ||
7556 					!is_mddev_idle(mddev, 0)) {
7557 				msleep(500);
7558 				goto repeat;
7559 			}
7560 		}
7561 	}
7562 	printk(KERN_INFO "md: %s: %s done.\n",mdname(mddev), desc);
7563 	/*
7564 	 * this also signals 'finished resyncing' to md_stop
7565 	 */
7566  out:
7567 	blk_finish_plug(&plug);
7568 	wait_event(mddev->recovery_wait, !atomic_read(&mddev->recovery_active));
7569 
7570 	/* tell personality that we are finished */
7571 	mddev->pers->sync_request(mddev, max_sectors, &skipped, 1);
7572 
7573 	if (!test_bit(MD_RECOVERY_CHECK, &mddev->recovery) &&
7574 	    mddev->curr_resync > 2) {
7575 		if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
7576 			if (test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
7577 				if (mddev->curr_resync >= mddev->recovery_cp) {
7578 					printk(KERN_INFO
7579 					       "md: checkpointing %s of %s.\n",
7580 					       desc, mdname(mddev));
7581 					mddev->recovery_cp =
7582 						mddev->curr_resync_completed;
7583 				}
7584 			} else
7585 				mddev->recovery_cp = MaxSector;
7586 		} else {
7587 			if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery))
7588 				mddev->curr_resync = MaxSector;
7589 			rcu_read_lock();
7590 			rdev_for_each_rcu(rdev, mddev)
7591 				if (rdev->raid_disk >= 0 &&
7592 				    mddev->delta_disks >= 0 &&
7593 				    !test_bit(Faulty, &rdev->flags) &&
7594 				    !test_bit(In_sync, &rdev->flags) &&
7595 				    rdev->recovery_offset < mddev->curr_resync)
7596 					rdev->recovery_offset = mddev->curr_resync;
7597 			rcu_read_unlock();
7598 		}
7599 	}
7600  skip:
7601 	set_bit(MD_CHANGE_DEVS, &mddev->flags);
7602 
7603 	if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
7604 		/* We completed so min/max setting can be forgotten if used. */
7605 		if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
7606 			mddev->resync_min = 0;
7607 		mddev->resync_max = MaxSector;
7608 	} else if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
7609 		mddev->resync_min = mddev->curr_resync_completed;
7610 	mddev->curr_resync = 0;
7611 	wake_up(&resync_wait);
7612 	set_bit(MD_RECOVERY_DONE, &mddev->recovery);
7613 	md_wakeup_thread(mddev->thread);
7614 	return;
7615 
7616  interrupted:
7617 	/*
7618 	 * got a signal, exit.
7619 	 */
7620 	printk(KERN_INFO
7621 	       "md: md_do_sync() got signal ... exiting\n");
7622 	set_bit(MD_RECOVERY_INTR, &mddev->recovery);
7623 	goto out;
7624 
7625 }
7626 EXPORT_SYMBOL_GPL(md_do_sync);
7627 
7628 static int remove_and_add_spares(struct mddev *mddev)
7629 {
7630 	struct md_rdev *rdev;
7631 	int spares = 0;
7632 	int removed = 0;
7633 
7634 	mddev->curr_resync_completed = 0;
7635 
7636 	rdev_for_each(rdev, mddev)
7637 		if (rdev->raid_disk >= 0 &&
7638 		    !test_bit(Blocked, &rdev->flags) &&
7639 		    (test_bit(Faulty, &rdev->flags) ||
7640 		     ! test_bit(In_sync, &rdev->flags)) &&
7641 		    atomic_read(&rdev->nr_pending)==0) {
7642 			if (mddev->pers->hot_remove_disk(
7643 				    mddev, rdev) == 0) {
7644 				sysfs_unlink_rdev(mddev, rdev);
7645 				rdev->raid_disk = -1;
7646 				removed++;
7647 			}
7648 		}
7649 	if (removed)
7650 		sysfs_notify(&mddev->kobj, NULL,
7651 			     "degraded");
7652 
7653 
7654 	rdev_for_each(rdev, mddev) {
7655 		if (rdev->raid_disk >= 0 &&
7656 		    !test_bit(In_sync, &rdev->flags) &&
7657 		    !test_bit(Faulty, &rdev->flags))
7658 			spares++;
7659 		if (rdev->raid_disk < 0
7660 		    && !test_bit(Faulty, &rdev->flags)) {
7661 			rdev->recovery_offset = 0;
7662 			if (mddev->pers->
7663 			    hot_add_disk(mddev, rdev) == 0) {
7664 				if (sysfs_link_rdev(mddev, rdev))
7665 					/* failure here is OK */;
7666 				spares++;
7667 				md_new_event(mddev);
7668 				set_bit(MD_CHANGE_DEVS, &mddev->flags);
7669 			}
7670 		}
7671 	}
7672 	return spares;
7673 }
7674 
7675 static void reap_sync_thread(struct mddev *mddev)
7676 {
7677 	struct md_rdev *rdev;
7678 
7679 	/* resync has finished, collect result */
7680 	md_unregister_thread(&mddev->sync_thread);
7681 	if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery) &&
7682 	    !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
7683 		/* success...*/
7684 		/* activate any spares */
7685 		if (mddev->pers->spare_active(mddev))
7686 			sysfs_notify(&mddev->kobj, NULL,
7687 				     "degraded");
7688 	}
7689 	if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
7690 	    mddev->pers->finish_reshape)
7691 		mddev->pers->finish_reshape(mddev);
7692 
7693 	/* If array is no-longer degraded, then any saved_raid_disk
7694 	 * information must be scrapped.  Also if any device is now
7695 	 * In_sync we must scrape the saved_raid_disk for that device
7696 	 * do the superblock for an incrementally recovered device
7697 	 * written out.
7698 	 */
7699 	rdev_for_each(rdev, mddev)
7700 		if (!mddev->degraded ||
7701 		    test_bit(In_sync, &rdev->flags))
7702 			rdev->saved_raid_disk = -1;
7703 
7704 	md_update_sb(mddev, 1);
7705 	clear_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
7706 	clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
7707 	clear_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
7708 	clear_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
7709 	clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
7710 	/* flag recovery needed just to double check */
7711 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
7712 	sysfs_notify_dirent_safe(mddev->sysfs_action);
7713 	md_new_event(mddev);
7714 	if (mddev->event_work.func)
7715 		queue_work(md_misc_wq, &mddev->event_work);
7716 }
7717 
7718 /*
7719  * This routine is regularly called by all per-raid-array threads to
7720  * deal with generic issues like resync and super-block update.
7721  * Raid personalities that don't have a thread (linear/raid0) do not
7722  * need this as they never do any recovery or update the superblock.
7723  *
7724  * It does not do any resync itself, but rather "forks" off other threads
7725  * to do that as needed.
7726  * When it is determined that resync is needed, we set MD_RECOVERY_RUNNING in
7727  * "->recovery" and create a thread at ->sync_thread.
7728  * When the thread finishes it sets MD_RECOVERY_DONE
7729  * and wakeups up this thread which will reap the thread and finish up.
7730  * This thread also removes any faulty devices (with nr_pending == 0).
7731  *
7732  * The overall approach is:
7733  *  1/ if the superblock needs updating, update it.
7734  *  2/ If a recovery thread is running, don't do anything else.
7735  *  3/ If recovery has finished, clean up, possibly marking spares active.
7736  *  4/ If there are any faulty devices, remove them.
7737  *  5/ If array is degraded, try to add spares devices
7738  *  6/ If array has spares or is not in-sync, start a resync thread.
7739  */
7740 void md_check_recovery(struct mddev *mddev)
7741 {
7742 	if (mddev->suspended)
7743 		return;
7744 
7745 	if (mddev->bitmap)
7746 		bitmap_daemon_work(mddev);
7747 
7748 	if (signal_pending(current)) {
7749 		if (mddev->pers->sync_request && !mddev->external) {
7750 			printk(KERN_INFO "md: %s in immediate safe mode\n",
7751 			       mdname(mddev));
7752 			mddev->safemode = 2;
7753 		}
7754 		flush_signals(current);
7755 	}
7756 
7757 	if (mddev->ro && !test_bit(MD_RECOVERY_NEEDED, &mddev->recovery))
7758 		return;
7759 	if ( ! (
7760 		(mddev->flags & ~ (1<<MD_CHANGE_PENDING)) ||
7761 		test_bit(MD_RECOVERY_NEEDED, &mddev->recovery) ||
7762 		test_bit(MD_RECOVERY_DONE, &mddev->recovery) ||
7763 		(mddev->external == 0 && mddev->safemode == 1) ||
7764 		(mddev->safemode == 2 && ! atomic_read(&mddev->writes_pending)
7765 		 && !mddev->in_sync && mddev->recovery_cp == MaxSector)
7766 		))
7767 		return;
7768 
7769 	if (mddev_trylock(mddev)) {
7770 		int spares = 0;
7771 
7772 		if (mddev->ro) {
7773 			/* Only thing we do on a ro array is remove
7774 			 * failed devices.
7775 			 */
7776 			struct md_rdev *rdev;
7777 			rdev_for_each(rdev, mddev)
7778 				if (rdev->raid_disk >= 0 &&
7779 				    !test_bit(Blocked, &rdev->flags) &&
7780 				    test_bit(Faulty, &rdev->flags) &&
7781 				    atomic_read(&rdev->nr_pending)==0) {
7782 					if (mddev->pers->hot_remove_disk(
7783 						    mddev, rdev) == 0) {
7784 						sysfs_unlink_rdev(mddev, rdev);
7785 						rdev->raid_disk = -1;
7786 					}
7787 				}
7788 			clear_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
7789 			goto unlock;
7790 		}
7791 
7792 		if (!mddev->external) {
7793 			int did_change = 0;
7794 			spin_lock_irq(&mddev->write_lock);
7795 			if (mddev->safemode &&
7796 			    !atomic_read(&mddev->writes_pending) &&
7797 			    !mddev->in_sync &&
7798 			    mddev->recovery_cp == MaxSector) {
7799 				mddev->in_sync = 1;
7800 				did_change = 1;
7801 				set_bit(MD_CHANGE_CLEAN, &mddev->flags);
7802 			}
7803 			if (mddev->safemode == 1)
7804 				mddev->safemode = 0;
7805 			spin_unlock_irq(&mddev->write_lock);
7806 			if (did_change)
7807 				sysfs_notify_dirent_safe(mddev->sysfs_state);
7808 		}
7809 
7810 		if (mddev->flags)
7811 			md_update_sb(mddev, 0);
7812 
7813 		if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) &&
7814 		    !test_bit(MD_RECOVERY_DONE, &mddev->recovery)) {
7815 			/* resync/recovery still happening */
7816 			clear_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
7817 			goto unlock;
7818 		}
7819 		if (mddev->sync_thread) {
7820 			reap_sync_thread(mddev);
7821 			goto unlock;
7822 		}
7823 		/* Set RUNNING before clearing NEEDED to avoid
7824 		 * any transients in the value of "sync_action".
7825 		 */
7826 		set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
7827 		/* Clear some bits that don't mean anything, but
7828 		 * might be left set
7829 		 */
7830 		clear_bit(MD_RECOVERY_INTR, &mddev->recovery);
7831 		clear_bit(MD_RECOVERY_DONE, &mddev->recovery);
7832 
7833 		if (!test_and_clear_bit(MD_RECOVERY_NEEDED, &mddev->recovery) ||
7834 		    test_bit(MD_RECOVERY_FROZEN, &mddev->recovery))
7835 			goto unlock;
7836 		/* no recovery is running.
7837 		 * remove any failed drives, then
7838 		 * add spares if possible.
7839 		 * Spare are also removed and re-added, to allow
7840 		 * the personality to fail the re-add.
7841 		 */
7842 
7843 		if (mddev->reshape_position != MaxSector) {
7844 			if (mddev->pers->check_reshape == NULL ||
7845 			    mddev->pers->check_reshape(mddev) != 0)
7846 				/* Cannot proceed */
7847 				goto unlock;
7848 			set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
7849 			clear_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
7850 		} else if ((spares = remove_and_add_spares(mddev))) {
7851 			clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
7852 			clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
7853 			clear_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
7854 			set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
7855 		} else if (mddev->recovery_cp < MaxSector) {
7856 			set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
7857 			clear_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
7858 		} else if (!test_bit(MD_RECOVERY_SYNC, &mddev->recovery))
7859 			/* nothing to be done ... */
7860 			goto unlock;
7861 
7862 		if (mddev->pers->sync_request) {
7863 			if (spares) {
7864 				/* We are adding a device or devices to an array
7865 				 * which has the bitmap stored on all devices.
7866 				 * So make sure all bitmap pages get written
7867 				 */
7868 				bitmap_write_all(mddev->bitmap);
7869 			}
7870 			mddev->sync_thread = md_register_thread(md_do_sync,
7871 								mddev,
7872 								"resync");
7873 			if (!mddev->sync_thread) {
7874 				printk(KERN_ERR "%s: could not start resync"
7875 					" thread...\n",
7876 					mdname(mddev));
7877 				/* leave the spares where they are, it shouldn't hurt */
7878 				clear_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
7879 				clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
7880 				clear_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
7881 				clear_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
7882 				clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
7883 			} else
7884 				md_wakeup_thread(mddev->sync_thread);
7885 			sysfs_notify_dirent_safe(mddev->sysfs_action);
7886 			md_new_event(mddev);
7887 		}
7888 	unlock:
7889 		if (!mddev->sync_thread) {
7890 			clear_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
7891 			if (test_and_clear_bit(MD_RECOVERY_RECOVER,
7892 					       &mddev->recovery))
7893 				if (mddev->sysfs_action)
7894 					sysfs_notify_dirent_safe(mddev->sysfs_action);
7895 		}
7896 		mddev_unlock(mddev);
7897 	}
7898 }
7899 
7900 void md_wait_for_blocked_rdev(struct md_rdev *rdev, struct mddev *mddev)
7901 {
7902 	sysfs_notify_dirent_safe(rdev->sysfs_state);
7903 	wait_event_timeout(rdev->blocked_wait,
7904 			   !test_bit(Blocked, &rdev->flags) &&
7905 			   !test_bit(BlockedBadBlocks, &rdev->flags),
7906 			   msecs_to_jiffies(5000));
7907 	rdev_dec_pending(rdev, mddev);
7908 }
7909 EXPORT_SYMBOL(md_wait_for_blocked_rdev);
7910 
7911 void md_finish_reshape(struct mddev *mddev)
7912 {
7913 	/* called be personality module when reshape completes. */
7914 	struct md_rdev *rdev;
7915 
7916 	rdev_for_each(rdev, mddev) {
7917 		if (rdev->data_offset > rdev->new_data_offset)
7918 			rdev->sectors += rdev->data_offset - rdev->new_data_offset;
7919 		else
7920 			rdev->sectors -= rdev->new_data_offset - rdev->data_offset;
7921 		rdev->data_offset = rdev->new_data_offset;
7922 	}
7923 }
7924 EXPORT_SYMBOL(md_finish_reshape);
7925 
7926 /* Bad block management.
7927  * We can record which blocks on each device are 'bad' and so just
7928  * fail those blocks, or that stripe, rather than the whole device.
7929  * Entries in the bad-block table are 64bits wide.  This comprises:
7930  * Length of bad-range, in sectors: 0-511 for lengths 1-512
7931  * Start of bad-range, sector offset, 54 bits (allows 8 exbibytes)
7932  *  A 'shift' can be set so that larger blocks are tracked and
7933  *  consequently larger devices can be covered.
7934  * 'Acknowledged' flag - 1 bit. - the most significant bit.
7935  *
7936  * Locking of the bad-block table uses a seqlock so md_is_badblock
7937  * might need to retry if it is very unlucky.
7938  * We will sometimes want to check for bad blocks in a bi_end_io function,
7939  * so we use the write_seqlock_irq variant.
7940  *
7941  * When looking for a bad block we specify a range and want to
7942  * know if any block in the range is bad.  So we binary-search
7943  * to the last range that starts at-or-before the given endpoint,
7944  * (or "before the sector after the target range")
7945  * then see if it ends after the given start.
7946  * We return
7947  *  0 if there are no known bad blocks in the range
7948  *  1 if there are known bad block which are all acknowledged
7949  * -1 if there are bad blocks which have not yet been acknowledged in metadata.
7950  * plus the start/length of the first bad section we overlap.
7951  */
7952 int md_is_badblock(struct badblocks *bb, sector_t s, int sectors,
7953 		   sector_t *first_bad, int *bad_sectors)
7954 {
7955 	int hi;
7956 	int lo = 0;
7957 	u64 *p = bb->page;
7958 	int rv = 0;
7959 	sector_t target = s + sectors;
7960 	unsigned seq;
7961 
7962 	if (bb->shift > 0) {
7963 		/* round the start down, and the end up */
7964 		s >>= bb->shift;
7965 		target += (1<<bb->shift) - 1;
7966 		target >>= bb->shift;
7967 		sectors = target - s;
7968 	}
7969 	/* 'target' is now the first block after the bad range */
7970 
7971 retry:
7972 	seq = read_seqbegin(&bb->lock);
7973 
7974 	hi = bb->count;
7975 
7976 	/* Binary search between lo and hi for 'target'
7977 	 * i.e. for the last range that starts before 'target'
7978 	 */
7979 	/* INVARIANT: ranges before 'lo' and at-or-after 'hi'
7980 	 * are known not to be the last range before target.
7981 	 * VARIANT: hi-lo is the number of possible
7982 	 * ranges, and decreases until it reaches 1
7983 	 */
7984 	while (hi - lo > 1) {
7985 		int mid = (lo + hi) / 2;
7986 		sector_t a = BB_OFFSET(p[mid]);
7987 		if (a < target)
7988 			/* This could still be the one, earlier ranges
7989 			 * could not. */
7990 			lo = mid;
7991 		else
7992 			/* This and later ranges are definitely out. */
7993 			hi = mid;
7994 	}
7995 	/* 'lo' might be the last that started before target, but 'hi' isn't */
7996 	if (hi > lo) {
7997 		/* need to check all range that end after 's' to see if
7998 		 * any are unacknowledged.
7999 		 */
8000 		while (lo >= 0 &&
8001 		       BB_OFFSET(p[lo]) + BB_LEN(p[lo]) > s) {
8002 			if (BB_OFFSET(p[lo]) < target) {
8003 				/* starts before the end, and finishes after
8004 				 * the start, so they must overlap
8005 				 */
8006 				if (rv != -1 && BB_ACK(p[lo]))
8007 					rv = 1;
8008 				else
8009 					rv = -1;
8010 				*first_bad = BB_OFFSET(p[lo]);
8011 				*bad_sectors = BB_LEN(p[lo]);
8012 			}
8013 			lo--;
8014 		}
8015 	}
8016 
8017 	if (read_seqretry(&bb->lock, seq))
8018 		goto retry;
8019 
8020 	return rv;
8021 }
8022 EXPORT_SYMBOL_GPL(md_is_badblock);
8023 
8024 /*
8025  * Add a range of bad blocks to the table.
8026  * This might extend the table, or might contract it
8027  * if two adjacent ranges can be merged.
8028  * We binary-search to find the 'insertion' point, then
8029  * decide how best to handle it.
8030  */
8031 static int md_set_badblocks(struct badblocks *bb, sector_t s, int sectors,
8032 			    int acknowledged)
8033 {
8034 	u64 *p;
8035 	int lo, hi;
8036 	int rv = 1;
8037 
8038 	if (bb->shift < 0)
8039 		/* badblocks are disabled */
8040 		return 0;
8041 
8042 	if (bb->shift) {
8043 		/* round the start down, and the end up */
8044 		sector_t next = s + sectors;
8045 		s >>= bb->shift;
8046 		next += (1<<bb->shift) - 1;
8047 		next >>= bb->shift;
8048 		sectors = next - s;
8049 	}
8050 
8051 	write_seqlock_irq(&bb->lock);
8052 
8053 	p = bb->page;
8054 	lo = 0;
8055 	hi = bb->count;
8056 	/* Find the last range that starts at-or-before 's' */
8057 	while (hi - lo > 1) {
8058 		int mid = (lo + hi) / 2;
8059 		sector_t a = BB_OFFSET(p[mid]);
8060 		if (a <= s)
8061 			lo = mid;
8062 		else
8063 			hi = mid;
8064 	}
8065 	if (hi > lo && BB_OFFSET(p[lo]) > s)
8066 		hi = lo;
8067 
8068 	if (hi > lo) {
8069 		/* we found a range that might merge with the start
8070 		 * of our new range
8071 		 */
8072 		sector_t a = BB_OFFSET(p[lo]);
8073 		sector_t e = a + BB_LEN(p[lo]);
8074 		int ack = BB_ACK(p[lo]);
8075 		if (e >= s) {
8076 			/* Yes, we can merge with a previous range */
8077 			if (s == a && s + sectors >= e)
8078 				/* new range covers old */
8079 				ack = acknowledged;
8080 			else
8081 				ack = ack && acknowledged;
8082 
8083 			if (e < s + sectors)
8084 				e = s + sectors;
8085 			if (e - a <= BB_MAX_LEN) {
8086 				p[lo] = BB_MAKE(a, e-a, ack);
8087 				s = e;
8088 			} else {
8089 				/* does not all fit in one range,
8090 				 * make p[lo] maximal
8091 				 */
8092 				if (BB_LEN(p[lo]) != BB_MAX_LEN)
8093 					p[lo] = BB_MAKE(a, BB_MAX_LEN, ack);
8094 				s = a + BB_MAX_LEN;
8095 			}
8096 			sectors = e - s;
8097 		}
8098 	}
8099 	if (sectors && hi < bb->count) {
8100 		/* 'hi' points to the first range that starts after 's'.
8101 		 * Maybe we can merge with the start of that range */
8102 		sector_t a = BB_OFFSET(p[hi]);
8103 		sector_t e = a + BB_LEN(p[hi]);
8104 		int ack = BB_ACK(p[hi]);
8105 		if (a <= s + sectors) {
8106 			/* merging is possible */
8107 			if (e <= s + sectors) {
8108 				/* full overlap */
8109 				e = s + sectors;
8110 				ack = acknowledged;
8111 			} else
8112 				ack = ack && acknowledged;
8113 
8114 			a = s;
8115 			if (e - a <= BB_MAX_LEN) {
8116 				p[hi] = BB_MAKE(a, e-a, ack);
8117 				s = e;
8118 			} else {
8119 				p[hi] = BB_MAKE(a, BB_MAX_LEN, ack);
8120 				s = a + BB_MAX_LEN;
8121 			}
8122 			sectors = e - s;
8123 			lo = hi;
8124 			hi++;
8125 		}
8126 	}
8127 	if (sectors == 0 && hi < bb->count) {
8128 		/* we might be able to combine lo and hi */
8129 		/* Note: 's' is at the end of 'lo' */
8130 		sector_t a = BB_OFFSET(p[hi]);
8131 		int lolen = BB_LEN(p[lo]);
8132 		int hilen = BB_LEN(p[hi]);
8133 		int newlen = lolen + hilen - (s - a);
8134 		if (s >= a && newlen < BB_MAX_LEN) {
8135 			/* yes, we can combine them */
8136 			int ack = BB_ACK(p[lo]) && BB_ACK(p[hi]);
8137 			p[lo] = BB_MAKE(BB_OFFSET(p[lo]), newlen, ack);
8138 			memmove(p + hi, p + hi + 1,
8139 				(bb->count - hi - 1) * 8);
8140 			bb->count--;
8141 		}
8142 	}
8143 	while (sectors) {
8144 		/* didn't merge (it all).
8145 		 * Need to add a range just before 'hi' */
8146 		if (bb->count >= MD_MAX_BADBLOCKS) {
8147 			/* No room for more */
8148 			rv = 0;
8149 			break;
8150 		} else {
8151 			int this_sectors = sectors;
8152 			memmove(p + hi + 1, p + hi,
8153 				(bb->count - hi) * 8);
8154 			bb->count++;
8155 
8156 			if (this_sectors > BB_MAX_LEN)
8157 				this_sectors = BB_MAX_LEN;
8158 			p[hi] = BB_MAKE(s, this_sectors, acknowledged);
8159 			sectors -= this_sectors;
8160 			s += this_sectors;
8161 		}
8162 	}
8163 
8164 	bb->changed = 1;
8165 	if (!acknowledged)
8166 		bb->unacked_exist = 1;
8167 	write_sequnlock_irq(&bb->lock);
8168 
8169 	return rv;
8170 }
8171 
8172 int rdev_set_badblocks(struct md_rdev *rdev, sector_t s, int sectors,
8173 		       int is_new)
8174 {
8175 	int rv;
8176 	if (is_new)
8177 		s += rdev->new_data_offset;
8178 	else
8179 		s += rdev->data_offset;
8180 	rv = md_set_badblocks(&rdev->badblocks,
8181 			      s, sectors, 0);
8182 	if (rv) {
8183 		/* Make sure they get written out promptly */
8184 		sysfs_notify_dirent_safe(rdev->sysfs_state);
8185 		set_bit(MD_CHANGE_CLEAN, &rdev->mddev->flags);
8186 		md_wakeup_thread(rdev->mddev->thread);
8187 	}
8188 	return rv;
8189 }
8190 EXPORT_SYMBOL_GPL(rdev_set_badblocks);
8191 
8192 /*
8193  * Remove a range of bad blocks from the table.
8194  * This may involve extending the table if we spilt a region,
8195  * but it must not fail.  So if the table becomes full, we just
8196  * drop the remove request.
8197  */
8198 static int md_clear_badblocks(struct badblocks *bb, sector_t s, int sectors)
8199 {
8200 	u64 *p;
8201 	int lo, hi;
8202 	sector_t target = s + sectors;
8203 	int rv = 0;
8204 
8205 	if (bb->shift > 0) {
8206 		/* When clearing we round the start up and the end down.
8207 		 * This should not matter as the shift should align with
8208 		 * the block size and no rounding should ever be needed.
8209 		 * However it is better the think a block is bad when it
8210 		 * isn't than to think a block is not bad when it is.
8211 		 */
8212 		s += (1<<bb->shift) - 1;
8213 		s >>= bb->shift;
8214 		target >>= bb->shift;
8215 		sectors = target - s;
8216 	}
8217 
8218 	write_seqlock_irq(&bb->lock);
8219 
8220 	p = bb->page;
8221 	lo = 0;
8222 	hi = bb->count;
8223 	/* Find the last range that starts before 'target' */
8224 	while (hi - lo > 1) {
8225 		int mid = (lo + hi) / 2;
8226 		sector_t a = BB_OFFSET(p[mid]);
8227 		if (a < target)
8228 			lo = mid;
8229 		else
8230 			hi = mid;
8231 	}
8232 	if (hi > lo) {
8233 		/* p[lo] is the last range that could overlap the
8234 		 * current range.  Earlier ranges could also overlap,
8235 		 * but only this one can overlap the end of the range.
8236 		 */
8237 		if (BB_OFFSET(p[lo]) + BB_LEN(p[lo]) > target) {
8238 			/* Partial overlap, leave the tail of this range */
8239 			int ack = BB_ACK(p[lo]);
8240 			sector_t a = BB_OFFSET(p[lo]);
8241 			sector_t end = a + BB_LEN(p[lo]);
8242 
8243 			if (a < s) {
8244 				/* we need to split this range */
8245 				if (bb->count >= MD_MAX_BADBLOCKS) {
8246 					rv = 0;
8247 					goto out;
8248 				}
8249 				memmove(p+lo+1, p+lo, (bb->count - lo) * 8);
8250 				bb->count++;
8251 				p[lo] = BB_MAKE(a, s-a, ack);
8252 				lo++;
8253 			}
8254 			p[lo] = BB_MAKE(target, end - target, ack);
8255 			/* there is no longer an overlap */
8256 			hi = lo;
8257 			lo--;
8258 		}
8259 		while (lo >= 0 &&
8260 		       BB_OFFSET(p[lo]) + BB_LEN(p[lo]) > s) {
8261 			/* This range does overlap */
8262 			if (BB_OFFSET(p[lo]) < s) {
8263 				/* Keep the early parts of this range. */
8264 				int ack = BB_ACK(p[lo]);
8265 				sector_t start = BB_OFFSET(p[lo]);
8266 				p[lo] = BB_MAKE(start, s - start, ack);
8267 				/* now low doesn't overlap, so.. */
8268 				break;
8269 			}
8270 			lo--;
8271 		}
8272 		/* 'lo' is strictly before, 'hi' is strictly after,
8273 		 * anything between needs to be discarded
8274 		 */
8275 		if (hi - lo > 1) {
8276 			memmove(p+lo+1, p+hi, (bb->count - hi) * 8);
8277 			bb->count -= (hi - lo - 1);
8278 		}
8279 	}
8280 
8281 	bb->changed = 1;
8282 out:
8283 	write_sequnlock_irq(&bb->lock);
8284 	return rv;
8285 }
8286 
8287 int rdev_clear_badblocks(struct md_rdev *rdev, sector_t s, int sectors,
8288 			 int is_new)
8289 {
8290 	if (is_new)
8291 		s += rdev->new_data_offset;
8292 	else
8293 		s += rdev->data_offset;
8294 	return md_clear_badblocks(&rdev->badblocks,
8295 				  s, sectors);
8296 }
8297 EXPORT_SYMBOL_GPL(rdev_clear_badblocks);
8298 
8299 /*
8300  * Acknowledge all bad blocks in a list.
8301  * This only succeeds if ->changed is clear.  It is used by
8302  * in-kernel metadata updates
8303  */
8304 void md_ack_all_badblocks(struct badblocks *bb)
8305 {
8306 	if (bb->page == NULL || bb->changed)
8307 		/* no point even trying */
8308 		return;
8309 	write_seqlock_irq(&bb->lock);
8310 
8311 	if (bb->changed == 0 && bb->unacked_exist) {
8312 		u64 *p = bb->page;
8313 		int i;
8314 		for (i = 0; i < bb->count ; i++) {
8315 			if (!BB_ACK(p[i])) {
8316 				sector_t start = BB_OFFSET(p[i]);
8317 				int len = BB_LEN(p[i]);
8318 				p[i] = BB_MAKE(start, len, 1);
8319 			}
8320 		}
8321 		bb->unacked_exist = 0;
8322 	}
8323 	write_sequnlock_irq(&bb->lock);
8324 }
8325 EXPORT_SYMBOL_GPL(md_ack_all_badblocks);
8326 
8327 /* sysfs access to bad-blocks list.
8328  * We present two files.
8329  * 'bad-blocks' lists sector numbers and lengths of ranges that
8330  *    are recorded as bad.  The list is truncated to fit within
8331  *    the one-page limit of sysfs.
8332  *    Writing "sector length" to this file adds an acknowledged
8333  *    bad block list.
8334  * 'unacknowledged-bad-blocks' lists bad blocks that have not yet
8335  *    been acknowledged.  Writing to this file adds bad blocks
8336  *    without acknowledging them.  This is largely for testing.
8337  */
8338 
8339 static ssize_t
8340 badblocks_show(struct badblocks *bb, char *page, int unack)
8341 {
8342 	size_t len;
8343 	int i;
8344 	u64 *p = bb->page;
8345 	unsigned seq;
8346 
8347 	if (bb->shift < 0)
8348 		return 0;
8349 
8350 retry:
8351 	seq = read_seqbegin(&bb->lock);
8352 
8353 	len = 0;
8354 	i = 0;
8355 
8356 	while (len < PAGE_SIZE && i < bb->count) {
8357 		sector_t s = BB_OFFSET(p[i]);
8358 		unsigned int length = BB_LEN(p[i]);
8359 		int ack = BB_ACK(p[i]);
8360 		i++;
8361 
8362 		if (unack && ack)
8363 			continue;
8364 
8365 		len += snprintf(page+len, PAGE_SIZE-len, "%llu %u\n",
8366 				(unsigned long long)s << bb->shift,
8367 				length << bb->shift);
8368 	}
8369 	if (unack && len == 0)
8370 		bb->unacked_exist = 0;
8371 
8372 	if (read_seqretry(&bb->lock, seq))
8373 		goto retry;
8374 
8375 	return len;
8376 }
8377 
8378 #define DO_DEBUG 1
8379 
8380 static ssize_t
8381 badblocks_store(struct badblocks *bb, const char *page, size_t len, int unack)
8382 {
8383 	unsigned long long sector;
8384 	int length;
8385 	char newline;
8386 #ifdef DO_DEBUG
8387 	/* Allow clearing via sysfs *only* for testing/debugging.
8388 	 * Normally only a successful write may clear a badblock
8389 	 */
8390 	int clear = 0;
8391 	if (page[0] == '-') {
8392 		clear = 1;
8393 		page++;
8394 	}
8395 #endif /* DO_DEBUG */
8396 
8397 	switch (sscanf(page, "%llu %d%c", &sector, &length, &newline)) {
8398 	case 3:
8399 		if (newline != '\n')
8400 			return -EINVAL;
8401 	case 2:
8402 		if (length <= 0)
8403 			return -EINVAL;
8404 		break;
8405 	default:
8406 		return -EINVAL;
8407 	}
8408 
8409 #ifdef DO_DEBUG
8410 	if (clear) {
8411 		md_clear_badblocks(bb, sector, length);
8412 		return len;
8413 	}
8414 #endif /* DO_DEBUG */
8415 	if (md_set_badblocks(bb, sector, length, !unack))
8416 		return len;
8417 	else
8418 		return -ENOSPC;
8419 }
8420 
8421 static int md_notify_reboot(struct notifier_block *this,
8422 			    unsigned long code, void *x)
8423 {
8424 	struct list_head *tmp;
8425 	struct mddev *mddev;
8426 	int need_delay = 0;
8427 
8428 	for_each_mddev(mddev, tmp) {
8429 		if (mddev_trylock(mddev)) {
8430 			if (mddev->pers)
8431 				__md_stop_writes(mddev);
8432 			mddev->safemode = 2;
8433 			mddev_unlock(mddev);
8434 		}
8435 		need_delay = 1;
8436 	}
8437 	/*
8438 	 * certain more exotic SCSI devices are known to be
8439 	 * volatile wrt too early system reboots. While the
8440 	 * right place to handle this issue is the given
8441 	 * driver, we do want to have a safe RAID driver ...
8442 	 */
8443 	if (need_delay)
8444 		mdelay(1000*1);
8445 
8446 	return NOTIFY_DONE;
8447 }
8448 
8449 static struct notifier_block md_notifier = {
8450 	.notifier_call	= md_notify_reboot,
8451 	.next		= NULL,
8452 	.priority	= INT_MAX, /* before any real devices */
8453 };
8454 
8455 static void md_geninit(void)
8456 {
8457 	pr_debug("md: sizeof(mdp_super_t) = %d\n", (int)sizeof(mdp_super_t));
8458 
8459 	proc_create("mdstat", S_IRUGO, NULL, &md_seq_fops);
8460 }
8461 
8462 static int __init md_init(void)
8463 {
8464 	int ret = -ENOMEM;
8465 
8466 	md_wq = alloc_workqueue("md", WQ_MEM_RECLAIM, 0);
8467 	if (!md_wq)
8468 		goto err_wq;
8469 
8470 	md_misc_wq = alloc_workqueue("md_misc", 0, 0);
8471 	if (!md_misc_wq)
8472 		goto err_misc_wq;
8473 
8474 	if ((ret = register_blkdev(MD_MAJOR, "md")) < 0)
8475 		goto err_md;
8476 
8477 	if ((ret = register_blkdev(0, "mdp")) < 0)
8478 		goto err_mdp;
8479 	mdp_major = ret;
8480 
8481 	blk_register_region(MKDEV(MD_MAJOR, 0), 1UL<<MINORBITS, THIS_MODULE,
8482 			    md_probe, NULL, NULL);
8483 	blk_register_region(MKDEV(mdp_major, 0), 1UL<<MINORBITS, THIS_MODULE,
8484 			    md_probe, NULL, NULL);
8485 
8486 	register_reboot_notifier(&md_notifier);
8487 	raid_table_header = register_sysctl_table(raid_root_table);
8488 
8489 	md_geninit();
8490 	return 0;
8491 
8492 err_mdp:
8493 	unregister_blkdev(MD_MAJOR, "md");
8494 err_md:
8495 	destroy_workqueue(md_misc_wq);
8496 err_misc_wq:
8497 	destroy_workqueue(md_wq);
8498 err_wq:
8499 	return ret;
8500 }
8501 
8502 #ifndef MODULE
8503 
8504 /*
8505  * Searches all registered partitions for autorun RAID arrays
8506  * at boot time.
8507  */
8508 
8509 static LIST_HEAD(all_detected_devices);
8510 struct detected_devices_node {
8511 	struct list_head list;
8512 	dev_t dev;
8513 };
8514 
8515 void md_autodetect_dev(dev_t dev)
8516 {
8517 	struct detected_devices_node *node_detected_dev;
8518 
8519 	node_detected_dev = kzalloc(sizeof(*node_detected_dev), GFP_KERNEL);
8520 	if (node_detected_dev) {
8521 		node_detected_dev->dev = dev;
8522 		list_add_tail(&node_detected_dev->list, &all_detected_devices);
8523 	} else {
8524 		printk(KERN_CRIT "md: md_autodetect_dev: kzalloc failed"
8525 			", skipping dev(%d,%d)\n", MAJOR(dev), MINOR(dev));
8526 	}
8527 }
8528 
8529 
8530 static void autostart_arrays(int part)
8531 {
8532 	struct md_rdev *rdev;
8533 	struct detected_devices_node *node_detected_dev;
8534 	dev_t dev;
8535 	int i_scanned, i_passed;
8536 
8537 	i_scanned = 0;
8538 	i_passed = 0;
8539 
8540 	printk(KERN_INFO "md: Autodetecting RAID arrays.\n");
8541 
8542 	while (!list_empty(&all_detected_devices) && i_scanned < INT_MAX) {
8543 		i_scanned++;
8544 		node_detected_dev = list_entry(all_detected_devices.next,
8545 					struct detected_devices_node, list);
8546 		list_del(&node_detected_dev->list);
8547 		dev = node_detected_dev->dev;
8548 		kfree(node_detected_dev);
8549 		rdev = md_import_device(dev,0, 90);
8550 		if (IS_ERR(rdev))
8551 			continue;
8552 
8553 		if (test_bit(Faulty, &rdev->flags)) {
8554 			MD_BUG();
8555 			continue;
8556 		}
8557 		set_bit(AutoDetected, &rdev->flags);
8558 		list_add(&rdev->same_set, &pending_raid_disks);
8559 		i_passed++;
8560 	}
8561 
8562 	printk(KERN_INFO "md: Scanned %d and added %d devices.\n",
8563 						i_scanned, i_passed);
8564 
8565 	autorun_devices(part);
8566 }
8567 
8568 #endif /* !MODULE */
8569 
8570 static __exit void md_exit(void)
8571 {
8572 	struct mddev *mddev;
8573 	struct list_head *tmp;
8574 
8575 	blk_unregister_region(MKDEV(MD_MAJOR,0), 1U << MINORBITS);
8576 	blk_unregister_region(MKDEV(mdp_major,0), 1U << MINORBITS);
8577 
8578 	unregister_blkdev(MD_MAJOR,"md");
8579 	unregister_blkdev(mdp_major, "mdp");
8580 	unregister_reboot_notifier(&md_notifier);
8581 	unregister_sysctl_table(raid_table_header);
8582 	remove_proc_entry("mdstat", NULL);
8583 	for_each_mddev(mddev, tmp) {
8584 		export_array(mddev);
8585 		mddev->hold_active = 0;
8586 	}
8587 	destroy_workqueue(md_misc_wq);
8588 	destroy_workqueue(md_wq);
8589 }
8590 
8591 subsys_initcall(md_init);
8592 module_exit(md_exit)
8593 
8594 static int get_ro(char *buffer, struct kernel_param *kp)
8595 {
8596 	return sprintf(buffer, "%d", start_readonly);
8597 }
8598 static int set_ro(const char *val, struct kernel_param *kp)
8599 {
8600 	char *e;
8601 	int num = simple_strtoul(val, &e, 10);
8602 	if (*val && (*e == '\0' || *e == '\n')) {
8603 		start_readonly = num;
8604 		return 0;
8605 	}
8606 	return -EINVAL;
8607 }
8608 
8609 module_param_call(start_ro, set_ro, get_ro, NULL, S_IRUSR|S_IWUSR);
8610 module_param(start_dirty_degraded, int, S_IRUGO|S_IWUSR);
8611 
8612 module_param_call(new_array, add_named_array, NULL, NULL, S_IWUSR);
8613 
8614 EXPORT_SYMBOL(register_md_personality);
8615 EXPORT_SYMBOL(unregister_md_personality);
8616 EXPORT_SYMBOL(md_error);
8617 EXPORT_SYMBOL(md_done_sync);
8618 EXPORT_SYMBOL(md_write_start);
8619 EXPORT_SYMBOL(md_write_end);
8620 EXPORT_SYMBOL(md_register_thread);
8621 EXPORT_SYMBOL(md_unregister_thread);
8622 EXPORT_SYMBOL(md_wakeup_thread);
8623 EXPORT_SYMBOL(md_check_recovery);
8624 MODULE_LICENSE("GPL");
8625 MODULE_DESCRIPTION("MD RAID framework");
8626 MODULE_ALIAS("md");
8627 MODULE_ALIAS_BLOCKDEV_MAJOR(MD_MAJOR);
8628