xref: /linux/drivers/md/md.c (revision d229807f669ba3dea9f64467ee965051c4366aed)
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/mutex.h>
40 #include <linux/buffer_head.h> /* for invalidate_bdev */
41 #include <linux/poll.h>
42 #include <linux/ctype.h>
43 #include <linux/string.h>
44 #include <linux/hdreg.h>
45 #include <linux/proc_fs.h>
46 #include <linux/random.h>
47 #include <linux/module.h>
48 #include <linux/reboot.h>
49 #include <linux/file.h>
50 #include <linux/compat.h>
51 #include <linux/delay.h>
52 #include <linux/raid/md_p.h>
53 #include <linux/raid/md_u.h>
54 #include <linux/slab.h>
55 #include "md.h"
56 #include "bitmap.h"
57 
58 #ifndef MODULE
59 static void autostart_arrays(int part);
60 #endif
61 
62 /* pers_list is a list of registered personalities protected
63  * by pers_lock.
64  * pers_lock does extra service to protect accesses to
65  * mddev->thread when the mutex cannot be held.
66  */
67 static LIST_HEAD(pers_list);
68 static DEFINE_SPINLOCK(pers_lock);
69 
70 static void md_print_devices(void);
71 
72 static DECLARE_WAIT_QUEUE_HEAD(resync_wait);
73 static struct workqueue_struct *md_wq;
74 static struct workqueue_struct *md_misc_wq;
75 
76 #define MD_BUG(x...) { printk("md: bug in file %s, line %d\n", __FILE__, __LINE__); md_print_devices(); }
77 
78 /*
79  * Default number of read corrections we'll attempt on an rdev
80  * before ejecting it from the array. We divide the read error
81  * count by 2 for every hour elapsed between read errors.
82  */
83 #define MD_DEFAULT_MAX_CORRECTED_READ_ERRORS 20
84 /*
85  * Current RAID-1,4,5 parallel reconstruction 'guaranteed speed limit'
86  * is 1000 KB/sec, so the extra system load does not show up that much.
87  * Increase it if you want to have more _guaranteed_ speed. Note that
88  * the RAID driver will use the maximum available bandwidth if the IO
89  * subsystem is idle. There is also an 'absolute maximum' reconstruction
90  * speed limit - in case reconstruction slows down your system despite
91  * idle IO detection.
92  *
93  * you can change it via /proc/sys/dev/raid/speed_limit_min and _max.
94  * or /sys/block/mdX/md/sync_speed_{min,max}
95  */
96 
97 static int sysctl_speed_limit_min = 1000;
98 static int sysctl_speed_limit_max = 200000;
99 static inline int speed_min(struct mddev *mddev)
100 {
101 	return mddev->sync_speed_min ?
102 		mddev->sync_speed_min : sysctl_speed_limit_min;
103 }
104 
105 static inline int speed_max(struct mddev *mddev)
106 {
107 	return mddev->sync_speed_max ?
108 		mddev->sync_speed_max : sysctl_speed_limit_max;
109 }
110 
111 static struct ctl_table_header *raid_table_header;
112 
113 static ctl_table raid_table[] = {
114 	{
115 		.procname	= "speed_limit_min",
116 		.data		= &sysctl_speed_limit_min,
117 		.maxlen		= sizeof(int),
118 		.mode		= S_IRUGO|S_IWUSR,
119 		.proc_handler	= proc_dointvec,
120 	},
121 	{
122 		.procname	= "speed_limit_max",
123 		.data		= &sysctl_speed_limit_max,
124 		.maxlen		= sizeof(int),
125 		.mode		= S_IRUGO|S_IWUSR,
126 		.proc_handler	= proc_dointvec,
127 	},
128 	{ }
129 };
130 
131 static ctl_table raid_dir_table[] = {
132 	{
133 		.procname	= "raid",
134 		.maxlen		= 0,
135 		.mode		= S_IRUGO|S_IXUGO,
136 		.child		= raid_table,
137 	},
138 	{ }
139 };
140 
141 static ctl_table raid_root_table[] = {
142 	{
143 		.procname	= "dev",
144 		.maxlen		= 0,
145 		.mode		= 0555,
146 		.child		= raid_dir_table,
147 	},
148 	{  }
149 };
150 
151 static const struct block_device_operations md_fops;
152 
153 static int start_readonly;
154 
155 /* bio_clone_mddev
156  * like bio_clone, but with a local bio set
157  */
158 
159 static void mddev_bio_destructor(struct bio *bio)
160 {
161 	struct mddev *mddev, **mddevp;
162 
163 	mddevp = (void*)bio;
164 	mddev = mddevp[-1];
165 
166 	bio_free(bio, mddev->bio_set);
167 }
168 
169 struct bio *bio_alloc_mddev(gfp_t gfp_mask, int nr_iovecs,
170 			    struct mddev *mddev)
171 {
172 	struct bio *b;
173 	struct mddev **mddevp;
174 
175 	if (!mddev || !mddev->bio_set)
176 		return bio_alloc(gfp_mask, nr_iovecs);
177 
178 	b = bio_alloc_bioset(gfp_mask, nr_iovecs,
179 			     mddev->bio_set);
180 	if (!b)
181 		return NULL;
182 	mddevp = (void*)b;
183 	mddevp[-1] = mddev;
184 	b->bi_destructor = mddev_bio_destructor;
185 	return b;
186 }
187 EXPORT_SYMBOL_GPL(bio_alloc_mddev);
188 
189 struct bio *bio_clone_mddev(struct bio *bio, gfp_t gfp_mask,
190 			    struct mddev *mddev)
191 {
192 	struct bio *b;
193 	struct mddev **mddevp;
194 
195 	if (!mddev || !mddev->bio_set)
196 		return bio_clone(bio, gfp_mask);
197 
198 	b = bio_alloc_bioset(gfp_mask, bio->bi_max_vecs,
199 			     mddev->bio_set);
200 	if (!b)
201 		return NULL;
202 	mddevp = (void*)b;
203 	mddevp[-1] = mddev;
204 	b->bi_destructor = mddev_bio_destructor;
205 	__bio_clone(b, bio);
206 	if (bio_integrity(bio)) {
207 		int ret;
208 
209 		ret = bio_integrity_clone(b, bio, gfp_mask, mddev->bio_set);
210 
211 		if (ret < 0) {
212 			bio_put(b);
213 			return NULL;
214 		}
215 	}
216 
217 	return b;
218 }
219 EXPORT_SYMBOL_GPL(bio_clone_mddev);
220 
221 void md_trim_bio(struct bio *bio, int offset, int size)
222 {
223 	/* 'bio' is a cloned bio which we need to trim to match
224 	 * the given offset and size.
225 	 * This requires adjusting bi_sector, bi_size, and bi_io_vec
226 	 */
227 	int i;
228 	struct bio_vec *bvec;
229 	int sofar = 0;
230 
231 	size <<= 9;
232 	if (offset == 0 && size == bio->bi_size)
233 		return;
234 
235 	bio->bi_sector += offset;
236 	bio->bi_size = size;
237 	offset <<= 9;
238 	clear_bit(BIO_SEG_VALID, &bio->bi_flags);
239 
240 	while (bio->bi_idx < bio->bi_vcnt &&
241 	       bio->bi_io_vec[bio->bi_idx].bv_len <= offset) {
242 		/* remove this whole bio_vec */
243 		offset -= bio->bi_io_vec[bio->bi_idx].bv_len;
244 		bio->bi_idx++;
245 	}
246 	if (bio->bi_idx < bio->bi_vcnt) {
247 		bio->bi_io_vec[bio->bi_idx].bv_offset += offset;
248 		bio->bi_io_vec[bio->bi_idx].bv_len -= offset;
249 	}
250 	/* avoid any complications with bi_idx being non-zero*/
251 	if (bio->bi_idx) {
252 		memmove(bio->bi_io_vec, bio->bi_io_vec+bio->bi_idx,
253 			(bio->bi_vcnt - bio->bi_idx) * sizeof(struct bio_vec));
254 		bio->bi_vcnt -= bio->bi_idx;
255 		bio->bi_idx = 0;
256 	}
257 	/* Make sure vcnt and last bv are not too big */
258 	bio_for_each_segment(bvec, bio, i) {
259 		if (sofar + bvec->bv_len > size)
260 			bvec->bv_len = size - sofar;
261 		if (bvec->bv_len == 0) {
262 			bio->bi_vcnt = i;
263 			break;
264 		}
265 		sofar += bvec->bv_len;
266 	}
267 }
268 EXPORT_SYMBOL_GPL(md_trim_bio);
269 
270 /*
271  * We have a system wide 'event count' that is incremented
272  * on any 'interesting' event, and readers of /proc/mdstat
273  * can use 'poll' or 'select' to find out when the event
274  * count increases.
275  *
276  * Events are:
277  *  start array, stop array, error, add device, remove device,
278  *  start build, activate spare
279  */
280 static DECLARE_WAIT_QUEUE_HEAD(md_event_waiters);
281 static atomic_t md_event_count;
282 void md_new_event(struct mddev *mddev)
283 {
284 	atomic_inc(&md_event_count);
285 	wake_up(&md_event_waiters);
286 }
287 EXPORT_SYMBOL_GPL(md_new_event);
288 
289 /* Alternate version that can be called from interrupts
290  * when calling sysfs_notify isn't needed.
291  */
292 static void md_new_event_inintr(struct mddev *mddev)
293 {
294 	atomic_inc(&md_event_count);
295 	wake_up(&md_event_waiters);
296 }
297 
298 /*
299  * Enables to iterate over all existing md arrays
300  * all_mddevs_lock protects this list.
301  */
302 static LIST_HEAD(all_mddevs);
303 static DEFINE_SPINLOCK(all_mddevs_lock);
304 
305 
306 /*
307  * iterates through all used mddevs in the system.
308  * We take care to grab the all_mddevs_lock whenever navigating
309  * the list, and to always hold a refcount when unlocked.
310  * Any code which breaks out of this loop while own
311  * a reference to the current mddev and must mddev_put it.
312  */
313 #define for_each_mddev(_mddev,_tmp)					\
314 									\
315 	for (({ spin_lock(&all_mddevs_lock); 				\
316 		_tmp = all_mddevs.next;					\
317 		_mddev = NULL;});					\
318 	     ({ if (_tmp != &all_mddevs)				\
319 			mddev_get(list_entry(_tmp, struct mddev, all_mddevs));\
320 		spin_unlock(&all_mddevs_lock);				\
321 		if (_mddev) mddev_put(_mddev);				\
322 		_mddev = list_entry(_tmp, struct mddev, all_mddevs);	\
323 		_tmp != &all_mddevs;});					\
324 	     ({ spin_lock(&all_mddevs_lock);				\
325 		_tmp = _tmp->next;})					\
326 		)
327 
328 
329 /* Rather than calling directly into the personality make_request function,
330  * IO requests come here first so that we can check if the device is
331  * being suspended pending a reconfiguration.
332  * We hold a refcount over the call to ->make_request.  By the time that
333  * call has finished, the bio has been linked into some internal structure
334  * and so is visible to ->quiesce(), so we don't need the refcount any more.
335  */
336 static int md_make_request(struct request_queue *q, struct bio *bio)
337 {
338 	const int rw = bio_data_dir(bio);
339 	struct mddev *mddev = q->queuedata;
340 	int rv;
341 	int cpu;
342 	unsigned int sectors;
343 
344 	if (mddev == NULL || mddev->pers == NULL
345 	    || !mddev->ready) {
346 		bio_io_error(bio);
347 		return 0;
348 	}
349 	smp_rmb(); /* Ensure implications of  'active' are visible */
350 	rcu_read_lock();
351 	if (mddev->suspended) {
352 		DEFINE_WAIT(__wait);
353 		for (;;) {
354 			prepare_to_wait(&mddev->sb_wait, &__wait,
355 					TASK_UNINTERRUPTIBLE);
356 			if (!mddev->suspended)
357 				break;
358 			rcu_read_unlock();
359 			schedule();
360 			rcu_read_lock();
361 		}
362 		finish_wait(&mddev->sb_wait, &__wait);
363 	}
364 	atomic_inc(&mddev->active_io);
365 	rcu_read_unlock();
366 
367 	/*
368 	 * save the sectors now since our bio can
369 	 * go away inside make_request
370 	 */
371 	sectors = bio_sectors(bio);
372 	rv = mddev->pers->make_request(mddev, bio);
373 
374 	cpu = part_stat_lock();
375 	part_stat_inc(cpu, &mddev->gendisk->part0, ios[rw]);
376 	part_stat_add(cpu, &mddev->gendisk->part0, sectors[rw], sectors);
377 	part_stat_unlock();
378 
379 	if (atomic_dec_and_test(&mddev->active_io) && mddev->suspended)
380 		wake_up(&mddev->sb_wait);
381 
382 	return rv;
383 }
384 
385 /* mddev_suspend makes sure no new requests are submitted
386  * to the device, and that any requests that have been submitted
387  * are completely handled.
388  * Once ->stop is called and completes, the module will be completely
389  * unused.
390  */
391 void mddev_suspend(struct mddev *mddev)
392 {
393 	BUG_ON(mddev->suspended);
394 	mddev->suspended = 1;
395 	synchronize_rcu();
396 	wait_event(mddev->sb_wait, atomic_read(&mddev->active_io) == 0);
397 	mddev->pers->quiesce(mddev, 1);
398 }
399 EXPORT_SYMBOL_GPL(mddev_suspend);
400 
401 void mddev_resume(struct mddev *mddev)
402 {
403 	mddev->suspended = 0;
404 	wake_up(&mddev->sb_wait);
405 	mddev->pers->quiesce(mddev, 0);
406 
407 	md_wakeup_thread(mddev->thread);
408 	md_wakeup_thread(mddev->sync_thread); /* possibly kick off a reshape */
409 }
410 EXPORT_SYMBOL_GPL(mddev_resume);
411 
412 int mddev_congested(struct mddev *mddev, int bits)
413 {
414 	return mddev->suspended;
415 }
416 EXPORT_SYMBOL(mddev_congested);
417 
418 /*
419  * Generic flush handling for md
420  */
421 
422 static void md_end_flush(struct bio *bio, int err)
423 {
424 	struct md_rdev *rdev = bio->bi_private;
425 	struct mddev *mddev = rdev->mddev;
426 
427 	rdev_dec_pending(rdev, mddev);
428 
429 	if (atomic_dec_and_test(&mddev->flush_pending)) {
430 		/* The pre-request flush has finished */
431 		queue_work(md_wq, &mddev->flush_work);
432 	}
433 	bio_put(bio);
434 }
435 
436 static void md_submit_flush_data(struct work_struct *ws);
437 
438 static void submit_flushes(struct work_struct *ws)
439 {
440 	struct mddev *mddev = container_of(ws, struct mddev, flush_work);
441 	struct md_rdev *rdev;
442 
443 	INIT_WORK(&mddev->flush_work, md_submit_flush_data);
444 	atomic_set(&mddev->flush_pending, 1);
445 	rcu_read_lock();
446 	list_for_each_entry_rcu(rdev, &mddev->disks, same_set)
447 		if (rdev->raid_disk >= 0 &&
448 		    !test_bit(Faulty, &rdev->flags)) {
449 			/* Take two references, one is dropped
450 			 * when request finishes, one after
451 			 * we reclaim rcu_read_lock
452 			 */
453 			struct bio *bi;
454 			atomic_inc(&rdev->nr_pending);
455 			atomic_inc(&rdev->nr_pending);
456 			rcu_read_unlock();
457 			bi = bio_alloc_mddev(GFP_KERNEL, 0, mddev);
458 			bi->bi_end_io = md_end_flush;
459 			bi->bi_private = rdev;
460 			bi->bi_bdev = rdev->bdev;
461 			atomic_inc(&mddev->flush_pending);
462 			submit_bio(WRITE_FLUSH, bi);
463 			rcu_read_lock();
464 			rdev_dec_pending(rdev, mddev);
465 		}
466 	rcu_read_unlock();
467 	if (atomic_dec_and_test(&mddev->flush_pending))
468 		queue_work(md_wq, &mddev->flush_work);
469 }
470 
471 static void md_submit_flush_data(struct work_struct *ws)
472 {
473 	struct mddev *mddev = container_of(ws, struct mddev, flush_work);
474 	struct bio *bio = mddev->flush_bio;
475 
476 	if (bio->bi_size == 0)
477 		/* an empty barrier - all done */
478 		bio_endio(bio, 0);
479 	else {
480 		bio->bi_rw &= ~REQ_FLUSH;
481 		if (mddev->pers->make_request(mddev, bio))
482 			generic_make_request(bio);
483 	}
484 
485 	mddev->flush_bio = NULL;
486 	wake_up(&mddev->sb_wait);
487 }
488 
489 void md_flush_request(struct mddev *mddev, struct bio *bio)
490 {
491 	spin_lock_irq(&mddev->write_lock);
492 	wait_event_lock_irq(mddev->sb_wait,
493 			    !mddev->flush_bio,
494 			    mddev->write_lock, /*nothing*/);
495 	mddev->flush_bio = bio;
496 	spin_unlock_irq(&mddev->write_lock);
497 
498 	INIT_WORK(&mddev->flush_work, submit_flushes);
499 	queue_work(md_wq, &mddev->flush_work);
500 }
501 EXPORT_SYMBOL(md_flush_request);
502 
503 /* Support for plugging.
504  * This mirrors the plugging support in request_queue, but does not
505  * require having a whole queue or request structures.
506  * We allocate an md_plug_cb for each md device and each thread it gets
507  * plugged on.  This links tot the private plug_handle structure in the
508  * personality data where we keep a count of the number of outstanding
509  * plugs so other code can see if a plug is active.
510  */
511 struct md_plug_cb {
512 	struct blk_plug_cb cb;
513 	struct mddev *mddev;
514 };
515 
516 static void plugger_unplug(struct blk_plug_cb *cb)
517 {
518 	struct md_plug_cb *mdcb = container_of(cb, struct md_plug_cb, cb);
519 	if (atomic_dec_and_test(&mdcb->mddev->plug_cnt))
520 		md_wakeup_thread(mdcb->mddev->thread);
521 	kfree(mdcb);
522 }
523 
524 /* Check that an unplug wakeup will come shortly.
525  * If not, wakeup the md thread immediately
526  */
527 int mddev_check_plugged(struct mddev *mddev)
528 {
529 	struct blk_plug *plug = current->plug;
530 	struct md_plug_cb *mdcb;
531 
532 	if (!plug)
533 		return 0;
534 
535 	list_for_each_entry(mdcb, &plug->cb_list, cb.list) {
536 		if (mdcb->cb.callback == plugger_unplug &&
537 		    mdcb->mddev == mddev) {
538 			/* Already on the list, move to top */
539 			if (mdcb != list_first_entry(&plug->cb_list,
540 						    struct md_plug_cb,
541 						    cb.list))
542 				list_move(&mdcb->cb.list, &plug->cb_list);
543 			return 1;
544 		}
545 	}
546 	/* Not currently on the callback list */
547 	mdcb = kmalloc(sizeof(*mdcb), GFP_ATOMIC);
548 	if (!mdcb)
549 		return 0;
550 
551 	mdcb->mddev = mddev;
552 	mdcb->cb.callback = plugger_unplug;
553 	atomic_inc(&mddev->plug_cnt);
554 	list_add(&mdcb->cb.list, &plug->cb_list);
555 	return 1;
556 }
557 EXPORT_SYMBOL_GPL(mddev_check_plugged);
558 
559 static inline struct mddev *mddev_get(struct mddev *mddev)
560 {
561 	atomic_inc(&mddev->active);
562 	return mddev;
563 }
564 
565 static void mddev_delayed_delete(struct work_struct *ws);
566 
567 static void mddev_put(struct mddev *mddev)
568 {
569 	struct bio_set *bs = NULL;
570 
571 	if (!atomic_dec_and_lock(&mddev->active, &all_mddevs_lock))
572 		return;
573 	if (!mddev->raid_disks && list_empty(&mddev->disks) &&
574 	    mddev->ctime == 0 && !mddev->hold_active) {
575 		/* Array is not configured at all, and not held active,
576 		 * so destroy it */
577 		list_del(&mddev->all_mddevs);
578 		bs = mddev->bio_set;
579 		mddev->bio_set = NULL;
580 		if (mddev->gendisk) {
581 			/* We did a probe so need to clean up.  Call
582 			 * queue_work inside the spinlock so that
583 			 * flush_workqueue() after mddev_find will
584 			 * succeed in waiting for the work to be done.
585 			 */
586 			INIT_WORK(&mddev->del_work, mddev_delayed_delete);
587 			queue_work(md_misc_wq, &mddev->del_work);
588 		} else
589 			kfree(mddev);
590 	}
591 	spin_unlock(&all_mddevs_lock);
592 	if (bs)
593 		bioset_free(bs);
594 }
595 
596 void mddev_init(struct mddev *mddev)
597 {
598 	mutex_init(&mddev->open_mutex);
599 	mutex_init(&mddev->reconfig_mutex);
600 	mutex_init(&mddev->bitmap_info.mutex);
601 	INIT_LIST_HEAD(&mddev->disks);
602 	INIT_LIST_HEAD(&mddev->all_mddevs);
603 	init_timer(&mddev->safemode_timer);
604 	atomic_set(&mddev->active, 1);
605 	atomic_set(&mddev->openers, 0);
606 	atomic_set(&mddev->active_io, 0);
607 	atomic_set(&mddev->plug_cnt, 0);
608 	spin_lock_init(&mddev->write_lock);
609 	atomic_set(&mddev->flush_pending, 0);
610 	init_waitqueue_head(&mddev->sb_wait);
611 	init_waitqueue_head(&mddev->recovery_wait);
612 	mddev->reshape_position = MaxSector;
613 	mddev->resync_min = 0;
614 	mddev->resync_max = MaxSector;
615 	mddev->level = LEVEL_NONE;
616 }
617 EXPORT_SYMBOL_GPL(mddev_init);
618 
619 static struct mddev * mddev_find(dev_t unit)
620 {
621 	struct mddev *mddev, *new = NULL;
622 
623 	if (unit && MAJOR(unit) != MD_MAJOR)
624 		unit &= ~((1<<MdpMinorShift)-1);
625 
626  retry:
627 	spin_lock(&all_mddevs_lock);
628 
629 	if (unit) {
630 		list_for_each_entry(mddev, &all_mddevs, all_mddevs)
631 			if (mddev->unit == unit) {
632 				mddev_get(mddev);
633 				spin_unlock(&all_mddevs_lock);
634 				kfree(new);
635 				return mddev;
636 			}
637 
638 		if (new) {
639 			list_add(&new->all_mddevs, &all_mddevs);
640 			spin_unlock(&all_mddevs_lock);
641 			new->hold_active = UNTIL_IOCTL;
642 			return new;
643 		}
644 	} else if (new) {
645 		/* find an unused unit number */
646 		static int next_minor = 512;
647 		int start = next_minor;
648 		int is_free = 0;
649 		int dev = 0;
650 		while (!is_free) {
651 			dev = MKDEV(MD_MAJOR, next_minor);
652 			next_minor++;
653 			if (next_minor > MINORMASK)
654 				next_minor = 0;
655 			if (next_minor == start) {
656 				/* Oh dear, all in use. */
657 				spin_unlock(&all_mddevs_lock);
658 				kfree(new);
659 				return NULL;
660 			}
661 
662 			is_free = 1;
663 			list_for_each_entry(mddev, &all_mddevs, all_mddevs)
664 				if (mddev->unit == dev) {
665 					is_free = 0;
666 					break;
667 				}
668 		}
669 		new->unit = dev;
670 		new->md_minor = MINOR(dev);
671 		new->hold_active = UNTIL_STOP;
672 		list_add(&new->all_mddevs, &all_mddevs);
673 		spin_unlock(&all_mddevs_lock);
674 		return new;
675 	}
676 	spin_unlock(&all_mddevs_lock);
677 
678 	new = kzalloc(sizeof(*new), GFP_KERNEL);
679 	if (!new)
680 		return NULL;
681 
682 	new->unit = unit;
683 	if (MAJOR(unit) == MD_MAJOR)
684 		new->md_minor = MINOR(unit);
685 	else
686 		new->md_minor = MINOR(unit) >> MdpMinorShift;
687 
688 	mddev_init(new);
689 
690 	goto retry;
691 }
692 
693 static inline int mddev_lock(struct mddev * mddev)
694 {
695 	return mutex_lock_interruptible(&mddev->reconfig_mutex);
696 }
697 
698 static inline int mddev_is_locked(struct mddev *mddev)
699 {
700 	return mutex_is_locked(&mddev->reconfig_mutex);
701 }
702 
703 static inline int mddev_trylock(struct mddev * mddev)
704 {
705 	return mutex_trylock(&mddev->reconfig_mutex);
706 }
707 
708 static struct attribute_group md_redundancy_group;
709 
710 static void mddev_unlock(struct mddev * mddev)
711 {
712 	if (mddev->to_remove) {
713 		/* These cannot be removed under reconfig_mutex as
714 		 * an access to the files will try to take reconfig_mutex
715 		 * while holding the file unremovable, which leads to
716 		 * a deadlock.
717 		 * So hold set sysfs_active while the remove in happeing,
718 		 * and anything else which might set ->to_remove or my
719 		 * otherwise change the sysfs namespace will fail with
720 		 * -EBUSY if sysfs_active is still set.
721 		 * We set sysfs_active under reconfig_mutex and elsewhere
722 		 * test it under the same mutex to ensure its correct value
723 		 * is seen.
724 		 */
725 		struct attribute_group *to_remove = mddev->to_remove;
726 		mddev->to_remove = NULL;
727 		mddev->sysfs_active = 1;
728 		mutex_unlock(&mddev->reconfig_mutex);
729 
730 		if (mddev->kobj.sd) {
731 			if (to_remove != &md_redundancy_group)
732 				sysfs_remove_group(&mddev->kobj, to_remove);
733 			if (mddev->pers == NULL ||
734 			    mddev->pers->sync_request == NULL) {
735 				sysfs_remove_group(&mddev->kobj, &md_redundancy_group);
736 				if (mddev->sysfs_action)
737 					sysfs_put(mddev->sysfs_action);
738 				mddev->sysfs_action = NULL;
739 			}
740 		}
741 		mddev->sysfs_active = 0;
742 	} else
743 		mutex_unlock(&mddev->reconfig_mutex);
744 
745 	/* As we've dropped the mutex we need a spinlock to
746 	 * make sure the thread doesn't disappear
747 	 */
748 	spin_lock(&pers_lock);
749 	md_wakeup_thread(mddev->thread);
750 	spin_unlock(&pers_lock);
751 }
752 
753 static struct md_rdev * find_rdev_nr(struct mddev *mddev, int nr)
754 {
755 	struct md_rdev *rdev;
756 
757 	list_for_each_entry(rdev, &mddev->disks, same_set)
758 		if (rdev->desc_nr == nr)
759 			return rdev;
760 
761 	return NULL;
762 }
763 
764 static struct md_rdev * find_rdev(struct mddev * mddev, dev_t dev)
765 {
766 	struct md_rdev *rdev;
767 
768 	list_for_each_entry(rdev, &mddev->disks, same_set)
769 		if (rdev->bdev->bd_dev == dev)
770 			return rdev;
771 
772 	return NULL;
773 }
774 
775 static struct md_personality *find_pers(int level, char *clevel)
776 {
777 	struct md_personality *pers;
778 	list_for_each_entry(pers, &pers_list, list) {
779 		if (level != LEVEL_NONE && pers->level == level)
780 			return pers;
781 		if (strcmp(pers->name, clevel)==0)
782 			return pers;
783 	}
784 	return NULL;
785 }
786 
787 /* return the offset of the super block in 512byte sectors */
788 static inline sector_t calc_dev_sboffset(struct md_rdev *rdev)
789 {
790 	sector_t num_sectors = i_size_read(rdev->bdev->bd_inode) / 512;
791 	return MD_NEW_SIZE_SECTORS(num_sectors);
792 }
793 
794 static int alloc_disk_sb(struct md_rdev * rdev)
795 {
796 	if (rdev->sb_page)
797 		MD_BUG();
798 
799 	rdev->sb_page = alloc_page(GFP_KERNEL);
800 	if (!rdev->sb_page) {
801 		printk(KERN_ALERT "md: out of memory.\n");
802 		return -ENOMEM;
803 	}
804 
805 	return 0;
806 }
807 
808 static void free_disk_sb(struct md_rdev * rdev)
809 {
810 	if (rdev->sb_page) {
811 		put_page(rdev->sb_page);
812 		rdev->sb_loaded = 0;
813 		rdev->sb_page = NULL;
814 		rdev->sb_start = 0;
815 		rdev->sectors = 0;
816 	}
817 	if (rdev->bb_page) {
818 		put_page(rdev->bb_page);
819 		rdev->bb_page = NULL;
820 	}
821 }
822 
823 
824 static void super_written(struct bio *bio, int error)
825 {
826 	struct md_rdev *rdev = bio->bi_private;
827 	struct mddev *mddev = rdev->mddev;
828 
829 	if (error || !test_bit(BIO_UPTODATE, &bio->bi_flags)) {
830 		printk("md: super_written gets error=%d, uptodate=%d\n",
831 		       error, test_bit(BIO_UPTODATE, &bio->bi_flags));
832 		WARN_ON(test_bit(BIO_UPTODATE, &bio->bi_flags));
833 		md_error(mddev, rdev);
834 	}
835 
836 	if (atomic_dec_and_test(&mddev->pending_writes))
837 		wake_up(&mddev->sb_wait);
838 	bio_put(bio);
839 }
840 
841 void md_super_write(struct mddev *mddev, struct md_rdev *rdev,
842 		   sector_t sector, int size, struct page *page)
843 {
844 	/* write first size bytes of page to sector of rdev
845 	 * Increment mddev->pending_writes before returning
846 	 * and decrement it on completion, waking up sb_wait
847 	 * if zero is reached.
848 	 * If an error occurred, call md_error
849 	 */
850 	struct bio *bio = bio_alloc_mddev(GFP_NOIO, 1, mddev);
851 
852 	bio->bi_bdev = rdev->meta_bdev ? rdev->meta_bdev : rdev->bdev;
853 	bio->bi_sector = sector;
854 	bio_add_page(bio, page, size, 0);
855 	bio->bi_private = rdev;
856 	bio->bi_end_io = super_written;
857 
858 	atomic_inc(&mddev->pending_writes);
859 	submit_bio(WRITE_FLUSH_FUA, bio);
860 }
861 
862 void md_super_wait(struct mddev *mddev)
863 {
864 	/* wait for all superblock writes that were scheduled to complete */
865 	DEFINE_WAIT(wq);
866 	for(;;) {
867 		prepare_to_wait(&mddev->sb_wait, &wq, TASK_UNINTERRUPTIBLE);
868 		if (atomic_read(&mddev->pending_writes)==0)
869 			break;
870 		schedule();
871 	}
872 	finish_wait(&mddev->sb_wait, &wq);
873 }
874 
875 static void bi_complete(struct bio *bio, int error)
876 {
877 	complete((struct completion*)bio->bi_private);
878 }
879 
880 int sync_page_io(struct md_rdev *rdev, sector_t sector, int size,
881 		 struct page *page, int rw, bool metadata_op)
882 {
883 	struct bio *bio = bio_alloc_mddev(GFP_NOIO, 1, rdev->mddev);
884 	struct completion event;
885 	int ret;
886 
887 	rw |= REQ_SYNC;
888 
889 	bio->bi_bdev = (metadata_op && rdev->meta_bdev) ?
890 		rdev->meta_bdev : rdev->bdev;
891 	if (metadata_op)
892 		bio->bi_sector = sector + rdev->sb_start;
893 	else
894 		bio->bi_sector = sector + rdev->data_offset;
895 	bio_add_page(bio, page, size, 0);
896 	init_completion(&event);
897 	bio->bi_private = &event;
898 	bio->bi_end_io = bi_complete;
899 	submit_bio(rw, bio);
900 	wait_for_completion(&event);
901 
902 	ret = test_bit(BIO_UPTODATE, &bio->bi_flags);
903 	bio_put(bio);
904 	return ret;
905 }
906 EXPORT_SYMBOL_GPL(sync_page_io);
907 
908 static int read_disk_sb(struct md_rdev * rdev, int size)
909 {
910 	char b[BDEVNAME_SIZE];
911 	if (!rdev->sb_page) {
912 		MD_BUG();
913 		return -EINVAL;
914 	}
915 	if (rdev->sb_loaded)
916 		return 0;
917 
918 
919 	if (!sync_page_io(rdev, 0, size, rdev->sb_page, READ, true))
920 		goto fail;
921 	rdev->sb_loaded = 1;
922 	return 0;
923 
924 fail:
925 	printk(KERN_WARNING "md: disabled device %s, could not read superblock.\n",
926 		bdevname(rdev->bdev,b));
927 	return -EINVAL;
928 }
929 
930 static int uuid_equal(mdp_super_t *sb1, mdp_super_t *sb2)
931 {
932 	return 	sb1->set_uuid0 == sb2->set_uuid0 &&
933 		sb1->set_uuid1 == sb2->set_uuid1 &&
934 		sb1->set_uuid2 == sb2->set_uuid2 &&
935 		sb1->set_uuid3 == sb2->set_uuid3;
936 }
937 
938 static int sb_equal(mdp_super_t *sb1, mdp_super_t *sb2)
939 {
940 	int ret;
941 	mdp_super_t *tmp1, *tmp2;
942 
943 	tmp1 = kmalloc(sizeof(*tmp1),GFP_KERNEL);
944 	tmp2 = kmalloc(sizeof(*tmp2),GFP_KERNEL);
945 
946 	if (!tmp1 || !tmp2) {
947 		ret = 0;
948 		printk(KERN_INFO "md.c sb_equal(): failed to allocate memory!\n");
949 		goto abort;
950 	}
951 
952 	*tmp1 = *sb1;
953 	*tmp2 = *sb2;
954 
955 	/*
956 	 * nr_disks is not constant
957 	 */
958 	tmp1->nr_disks = 0;
959 	tmp2->nr_disks = 0;
960 
961 	ret = (memcmp(tmp1, tmp2, MD_SB_GENERIC_CONSTANT_WORDS * 4) == 0);
962 abort:
963 	kfree(tmp1);
964 	kfree(tmp2);
965 	return ret;
966 }
967 
968 
969 static u32 md_csum_fold(u32 csum)
970 {
971 	csum = (csum & 0xffff) + (csum >> 16);
972 	return (csum & 0xffff) + (csum >> 16);
973 }
974 
975 static unsigned int calc_sb_csum(mdp_super_t * sb)
976 {
977 	u64 newcsum = 0;
978 	u32 *sb32 = (u32*)sb;
979 	int i;
980 	unsigned int disk_csum, csum;
981 
982 	disk_csum = sb->sb_csum;
983 	sb->sb_csum = 0;
984 
985 	for (i = 0; i < MD_SB_BYTES/4 ; i++)
986 		newcsum += sb32[i];
987 	csum = (newcsum & 0xffffffff) + (newcsum>>32);
988 
989 
990 #ifdef CONFIG_ALPHA
991 	/* This used to use csum_partial, which was wrong for several
992 	 * reasons including that different results are returned on
993 	 * different architectures.  It isn't critical that we get exactly
994 	 * the same return value as before (we always csum_fold before
995 	 * testing, and that removes any differences).  However as we
996 	 * know that csum_partial always returned a 16bit value on
997 	 * alphas, do a fold to maximise conformity to previous behaviour.
998 	 */
999 	sb->sb_csum = md_csum_fold(disk_csum);
1000 #else
1001 	sb->sb_csum = disk_csum;
1002 #endif
1003 	return csum;
1004 }
1005 
1006 
1007 /*
1008  * Handle superblock details.
1009  * We want to be able to handle multiple superblock formats
1010  * so we have a common interface to them all, and an array of
1011  * different handlers.
1012  * We rely on user-space to write the initial superblock, and support
1013  * reading and updating of superblocks.
1014  * Interface methods are:
1015  *   int load_super(struct md_rdev *dev, struct md_rdev *refdev, int minor_version)
1016  *      loads and validates a superblock on dev.
1017  *      if refdev != NULL, compare superblocks on both devices
1018  *    Return:
1019  *      0 - dev has a superblock that is compatible with refdev
1020  *      1 - dev has a superblock that is compatible and newer than refdev
1021  *          so dev should be used as the refdev in future
1022  *     -EINVAL superblock incompatible or invalid
1023  *     -othererror e.g. -EIO
1024  *
1025  *   int validate_super(struct mddev *mddev, struct md_rdev *dev)
1026  *      Verify that dev is acceptable into mddev.
1027  *       The first time, mddev->raid_disks will be 0, and data from
1028  *       dev should be merged in.  Subsequent calls check that dev
1029  *       is new enough.  Return 0 or -EINVAL
1030  *
1031  *   void sync_super(struct mddev *mddev, struct md_rdev *dev)
1032  *     Update the superblock for rdev with data in mddev
1033  *     This does not write to disc.
1034  *
1035  */
1036 
1037 struct super_type  {
1038 	char		    *name;
1039 	struct module	    *owner;
1040 	int		    (*load_super)(struct md_rdev *rdev, struct md_rdev *refdev,
1041 					  int minor_version);
1042 	int		    (*validate_super)(struct mddev *mddev, struct md_rdev *rdev);
1043 	void		    (*sync_super)(struct mddev *mddev, struct md_rdev *rdev);
1044 	unsigned long long  (*rdev_size_change)(struct md_rdev *rdev,
1045 						sector_t num_sectors);
1046 };
1047 
1048 /*
1049  * Check that the given mddev has no bitmap.
1050  *
1051  * This function is called from the run method of all personalities that do not
1052  * support bitmaps. It prints an error message and returns non-zero if mddev
1053  * has a bitmap. Otherwise, it returns 0.
1054  *
1055  */
1056 int md_check_no_bitmap(struct mddev *mddev)
1057 {
1058 	if (!mddev->bitmap_info.file && !mddev->bitmap_info.offset)
1059 		return 0;
1060 	printk(KERN_ERR "%s: bitmaps are not supported for %s\n",
1061 		mdname(mddev), mddev->pers->name);
1062 	return 1;
1063 }
1064 EXPORT_SYMBOL(md_check_no_bitmap);
1065 
1066 /*
1067  * load_super for 0.90.0
1068  */
1069 static int super_90_load(struct md_rdev *rdev, struct md_rdev *refdev, int minor_version)
1070 {
1071 	char b[BDEVNAME_SIZE], b2[BDEVNAME_SIZE];
1072 	mdp_super_t *sb;
1073 	int ret;
1074 
1075 	/*
1076 	 * Calculate the position of the superblock (512byte sectors),
1077 	 * it's at the end of the disk.
1078 	 *
1079 	 * It also happens to be a multiple of 4Kb.
1080 	 */
1081 	rdev->sb_start = calc_dev_sboffset(rdev);
1082 
1083 	ret = read_disk_sb(rdev, MD_SB_BYTES);
1084 	if (ret) return ret;
1085 
1086 	ret = -EINVAL;
1087 
1088 	bdevname(rdev->bdev, b);
1089 	sb = page_address(rdev->sb_page);
1090 
1091 	if (sb->md_magic != MD_SB_MAGIC) {
1092 		printk(KERN_ERR "md: invalid raid superblock magic on %s\n",
1093 		       b);
1094 		goto abort;
1095 	}
1096 
1097 	if (sb->major_version != 0 ||
1098 	    sb->minor_version < 90 ||
1099 	    sb->minor_version > 91) {
1100 		printk(KERN_WARNING "Bad version number %d.%d on %s\n",
1101 			sb->major_version, sb->minor_version,
1102 			b);
1103 		goto abort;
1104 	}
1105 
1106 	if (sb->raid_disks <= 0)
1107 		goto abort;
1108 
1109 	if (md_csum_fold(calc_sb_csum(sb)) != md_csum_fold(sb->sb_csum)) {
1110 		printk(KERN_WARNING "md: invalid superblock checksum on %s\n",
1111 			b);
1112 		goto abort;
1113 	}
1114 
1115 	rdev->preferred_minor = sb->md_minor;
1116 	rdev->data_offset = 0;
1117 	rdev->sb_size = MD_SB_BYTES;
1118 	rdev->badblocks.shift = -1;
1119 
1120 	if (sb->level == LEVEL_MULTIPATH)
1121 		rdev->desc_nr = -1;
1122 	else
1123 		rdev->desc_nr = sb->this_disk.number;
1124 
1125 	if (!refdev) {
1126 		ret = 1;
1127 	} else {
1128 		__u64 ev1, ev2;
1129 		mdp_super_t *refsb = page_address(refdev->sb_page);
1130 		if (!uuid_equal(refsb, sb)) {
1131 			printk(KERN_WARNING "md: %s has different UUID to %s\n",
1132 				b, bdevname(refdev->bdev,b2));
1133 			goto abort;
1134 		}
1135 		if (!sb_equal(refsb, sb)) {
1136 			printk(KERN_WARNING "md: %s has same UUID"
1137 			       " but different superblock to %s\n",
1138 			       b, bdevname(refdev->bdev, b2));
1139 			goto abort;
1140 		}
1141 		ev1 = md_event(sb);
1142 		ev2 = md_event(refsb);
1143 		if (ev1 > ev2)
1144 			ret = 1;
1145 		else
1146 			ret = 0;
1147 	}
1148 	rdev->sectors = rdev->sb_start;
1149 	/* Limit to 4TB as metadata cannot record more than that */
1150 	if (rdev->sectors >= (2ULL << 32))
1151 		rdev->sectors = (2ULL << 32) - 2;
1152 
1153 	if (rdev->sectors < ((sector_t)sb->size) * 2 && sb->level >= 1)
1154 		/* "this cannot possibly happen" ... */
1155 		ret = -EINVAL;
1156 
1157  abort:
1158 	return ret;
1159 }
1160 
1161 /*
1162  * validate_super for 0.90.0
1163  */
1164 static int super_90_validate(struct mddev *mddev, struct md_rdev *rdev)
1165 {
1166 	mdp_disk_t *desc;
1167 	mdp_super_t *sb = page_address(rdev->sb_page);
1168 	__u64 ev1 = md_event(sb);
1169 
1170 	rdev->raid_disk = -1;
1171 	clear_bit(Faulty, &rdev->flags);
1172 	clear_bit(In_sync, &rdev->flags);
1173 	clear_bit(WriteMostly, &rdev->flags);
1174 
1175 	if (mddev->raid_disks == 0) {
1176 		mddev->major_version = 0;
1177 		mddev->minor_version = sb->minor_version;
1178 		mddev->patch_version = sb->patch_version;
1179 		mddev->external = 0;
1180 		mddev->chunk_sectors = sb->chunk_size >> 9;
1181 		mddev->ctime = sb->ctime;
1182 		mddev->utime = sb->utime;
1183 		mddev->level = sb->level;
1184 		mddev->clevel[0] = 0;
1185 		mddev->layout = sb->layout;
1186 		mddev->raid_disks = sb->raid_disks;
1187 		mddev->dev_sectors = ((sector_t)sb->size) * 2;
1188 		mddev->events = ev1;
1189 		mddev->bitmap_info.offset = 0;
1190 		mddev->bitmap_info.default_offset = MD_SB_BYTES >> 9;
1191 
1192 		if (mddev->minor_version >= 91) {
1193 			mddev->reshape_position = sb->reshape_position;
1194 			mddev->delta_disks = sb->delta_disks;
1195 			mddev->new_level = sb->new_level;
1196 			mddev->new_layout = sb->new_layout;
1197 			mddev->new_chunk_sectors = sb->new_chunk >> 9;
1198 		} else {
1199 			mddev->reshape_position = MaxSector;
1200 			mddev->delta_disks = 0;
1201 			mddev->new_level = mddev->level;
1202 			mddev->new_layout = mddev->layout;
1203 			mddev->new_chunk_sectors = mddev->chunk_sectors;
1204 		}
1205 
1206 		if (sb->state & (1<<MD_SB_CLEAN))
1207 			mddev->recovery_cp = MaxSector;
1208 		else {
1209 			if (sb->events_hi == sb->cp_events_hi &&
1210 				sb->events_lo == sb->cp_events_lo) {
1211 				mddev->recovery_cp = sb->recovery_cp;
1212 			} else
1213 				mddev->recovery_cp = 0;
1214 		}
1215 
1216 		memcpy(mddev->uuid+0, &sb->set_uuid0, 4);
1217 		memcpy(mddev->uuid+4, &sb->set_uuid1, 4);
1218 		memcpy(mddev->uuid+8, &sb->set_uuid2, 4);
1219 		memcpy(mddev->uuid+12,&sb->set_uuid3, 4);
1220 
1221 		mddev->max_disks = MD_SB_DISKS;
1222 
1223 		if (sb->state & (1<<MD_SB_BITMAP_PRESENT) &&
1224 		    mddev->bitmap_info.file == NULL)
1225 			mddev->bitmap_info.offset =
1226 				mddev->bitmap_info.default_offset;
1227 
1228 	} else if (mddev->pers == NULL) {
1229 		/* Insist on good event counter while assembling, except
1230 		 * for spares (which don't need an event count) */
1231 		++ev1;
1232 		if (sb->disks[rdev->desc_nr].state & (
1233 			    (1<<MD_DISK_SYNC) | (1 << MD_DISK_ACTIVE)))
1234 			if (ev1 < mddev->events)
1235 				return -EINVAL;
1236 	} else if (mddev->bitmap) {
1237 		/* if adding to array with a bitmap, then we can accept an
1238 		 * older device ... but not too old.
1239 		 */
1240 		if (ev1 < mddev->bitmap->events_cleared)
1241 			return 0;
1242 	} else {
1243 		if (ev1 < mddev->events)
1244 			/* just a hot-add of a new device, leave raid_disk at -1 */
1245 			return 0;
1246 	}
1247 
1248 	if (mddev->level != LEVEL_MULTIPATH) {
1249 		desc = sb->disks + rdev->desc_nr;
1250 
1251 		if (desc->state & (1<<MD_DISK_FAULTY))
1252 			set_bit(Faulty, &rdev->flags);
1253 		else if (desc->state & (1<<MD_DISK_SYNC) /* &&
1254 			    desc->raid_disk < mddev->raid_disks */) {
1255 			set_bit(In_sync, &rdev->flags);
1256 			rdev->raid_disk = desc->raid_disk;
1257 		} else if (desc->state & (1<<MD_DISK_ACTIVE)) {
1258 			/* active but not in sync implies recovery up to
1259 			 * reshape position.  We don't know exactly where
1260 			 * that is, so set to zero for now */
1261 			if (mddev->minor_version >= 91) {
1262 				rdev->recovery_offset = 0;
1263 				rdev->raid_disk = desc->raid_disk;
1264 			}
1265 		}
1266 		if (desc->state & (1<<MD_DISK_WRITEMOSTLY))
1267 			set_bit(WriteMostly, &rdev->flags);
1268 	} else /* MULTIPATH are always insync */
1269 		set_bit(In_sync, &rdev->flags);
1270 	return 0;
1271 }
1272 
1273 /*
1274  * sync_super for 0.90.0
1275  */
1276 static void super_90_sync(struct mddev *mddev, struct md_rdev *rdev)
1277 {
1278 	mdp_super_t *sb;
1279 	struct md_rdev *rdev2;
1280 	int next_spare = mddev->raid_disks;
1281 
1282 
1283 	/* make rdev->sb match mddev data..
1284 	 *
1285 	 * 1/ zero out disks
1286 	 * 2/ Add info for each disk, keeping track of highest desc_nr (next_spare);
1287 	 * 3/ any empty disks < next_spare become removed
1288 	 *
1289 	 * disks[0] gets initialised to REMOVED because
1290 	 * we cannot be sure from other fields if it has
1291 	 * been initialised or not.
1292 	 */
1293 	int i;
1294 	int active=0, working=0,failed=0,spare=0,nr_disks=0;
1295 
1296 	rdev->sb_size = MD_SB_BYTES;
1297 
1298 	sb = page_address(rdev->sb_page);
1299 
1300 	memset(sb, 0, sizeof(*sb));
1301 
1302 	sb->md_magic = MD_SB_MAGIC;
1303 	sb->major_version = mddev->major_version;
1304 	sb->patch_version = mddev->patch_version;
1305 	sb->gvalid_words  = 0; /* ignored */
1306 	memcpy(&sb->set_uuid0, mddev->uuid+0, 4);
1307 	memcpy(&sb->set_uuid1, mddev->uuid+4, 4);
1308 	memcpy(&sb->set_uuid2, mddev->uuid+8, 4);
1309 	memcpy(&sb->set_uuid3, mddev->uuid+12,4);
1310 
1311 	sb->ctime = mddev->ctime;
1312 	sb->level = mddev->level;
1313 	sb->size = mddev->dev_sectors / 2;
1314 	sb->raid_disks = mddev->raid_disks;
1315 	sb->md_minor = mddev->md_minor;
1316 	sb->not_persistent = 0;
1317 	sb->utime = mddev->utime;
1318 	sb->state = 0;
1319 	sb->events_hi = (mddev->events>>32);
1320 	sb->events_lo = (u32)mddev->events;
1321 
1322 	if (mddev->reshape_position == MaxSector)
1323 		sb->minor_version = 90;
1324 	else {
1325 		sb->minor_version = 91;
1326 		sb->reshape_position = mddev->reshape_position;
1327 		sb->new_level = mddev->new_level;
1328 		sb->delta_disks = mddev->delta_disks;
1329 		sb->new_layout = mddev->new_layout;
1330 		sb->new_chunk = mddev->new_chunk_sectors << 9;
1331 	}
1332 	mddev->minor_version = sb->minor_version;
1333 	if (mddev->in_sync)
1334 	{
1335 		sb->recovery_cp = mddev->recovery_cp;
1336 		sb->cp_events_hi = (mddev->events>>32);
1337 		sb->cp_events_lo = (u32)mddev->events;
1338 		if (mddev->recovery_cp == MaxSector)
1339 			sb->state = (1<< MD_SB_CLEAN);
1340 	} else
1341 		sb->recovery_cp = 0;
1342 
1343 	sb->layout = mddev->layout;
1344 	sb->chunk_size = mddev->chunk_sectors << 9;
1345 
1346 	if (mddev->bitmap && mddev->bitmap_info.file == NULL)
1347 		sb->state |= (1<<MD_SB_BITMAP_PRESENT);
1348 
1349 	sb->disks[0].state = (1<<MD_DISK_REMOVED);
1350 	list_for_each_entry(rdev2, &mddev->disks, same_set) {
1351 		mdp_disk_t *d;
1352 		int desc_nr;
1353 		int is_active = test_bit(In_sync, &rdev2->flags);
1354 
1355 		if (rdev2->raid_disk >= 0 &&
1356 		    sb->minor_version >= 91)
1357 			/* we have nowhere to store the recovery_offset,
1358 			 * but if it is not below the reshape_position,
1359 			 * we can piggy-back on that.
1360 			 */
1361 			is_active = 1;
1362 		if (rdev2->raid_disk < 0 ||
1363 		    test_bit(Faulty, &rdev2->flags))
1364 			is_active = 0;
1365 		if (is_active)
1366 			desc_nr = rdev2->raid_disk;
1367 		else
1368 			desc_nr = next_spare++;
1369 		rdev2->desc_nr = desc_nr;
1370 		d = &sb->disks[rdev2->desc_nr];
1371 		nr_disks++;
1372 		d->number = rdev2->desc_nr;
1373 		d->major = MAJOR(rdev2->bdev->bd_dev);
1374 		d->minor = MINOR(rdev2->bdev->bd_dev);
1375 		if (is_active)
1376 			d->raid_disk = rdev2->raid_disk;
1377 		else
1378 			d->raid_disk = rdev2->desc_nr; /* compatibility */
1379 		if (test_bit(Faulty, &rdev2->flags))
1380 			d->state = (1<<MD_DISK_FAULTY);
1381 		else if (is_active) {
1382 			d->state = (1<<MD_DISK_ACTIVE);
1383 			if (test_bit(In_sync, &rdev2->flags))
1384 				d->state |= (1<<MD_DISK_SYNC);
1385 			active++;
1386 			working++;
1387 		} else {
1388 			d->state = 0;
1389 			spare++;
1390 			working++;
1391 		}
1392 		if (test_bit(WriteMostly, &rdev2->flags))
1393 			d->state |= (1<<MD_DISK_WRITEMOSTLY);
1394 	}
1395 	/* now set the "removed" and "faulty" bits on any missing devices */
1396 	for (i=0 ; i < mddev->raid_disks ; i++) {
1397 		mdp_disk_t *d = &sb->disks[i];
1398 		if (d->state == 0 && d->number == 0) {
1399 			d->number = i;
1400 			d->raid_disk = i;
1401 			d->state = (1<<MD_DISK_REMOVED);
1402 			d->state |= (1<<MD_DISK_FAULTY);
1403 			failed++;
1404 		}
1405 	}
1406 	sb->nr_disks = nr_disks;
1407 	sb->active_disks = active;
1408 	sb->working_disks = working;
1409 	sb->failed_disks = failed;
1410 	sb->spare_disks = spare;
1411 
1412 	sb->this_disk = sb->disks[rdev->desc_nr];
1413 	sb->sb_csum = calc_sb_csum(sb);
1414 }
1415 
1416 /*
1417  * rdev_size_change for 0.90.0
1418  */
1419 static unsigned long long
1420 super_90_rdev_size_change(struct md_rdev *rdev, sector_t num_sectors)
1421 {
1422 	if (num_sectors && num_sectors < rdev->mddev->dev_sectors)
1423 		return 0; /* component must fit device */
1424 	if (rdev->mddev->bitmap_info.offset)
1425 		return 0; /* can't move bitmap */
1426 	rdev->sb_start = calc_dev_sboffset(rdev);
1427 	if (!num_sectors || num_sectors > rdev->sb_start)
1428 		num_sectors = rdev->sb_start;
1429 	/* Limit to 4TB as metadata cannot record more than that.
1430 	 * 4TB == 2^32 KB, or 2*2^32 sectors.
1431 	 */
1432 	if (num_sectors >= (2ULL << 32))
1433 		num_sectors = (2ULL << 32) - 2;
1434 	md_super_write(rdev->mddev, rdev, rdev->sb_start, rdev->sb_size,
1435 		       rdev->sb_page);
1436 	md_super_wait(rdev->mddev);
1437 	return num_sectors;
1438 }
1439 
1440 
1441 /*
1442  * version 1 superblock
1443  */
1444 
1445 static __le32 calc_sb_1_csum(struct mdp_superblock_1 * sb)
1446 {
1447 	__le32 disk_csum;
1448 	u32 csum;
1449 	unsigned long long newcsum;
1450 	int size = 256 + le32_to_cpu(sb->max_dev)*2;
1451 	__le32 *isuper = (__le32*)sb;
1452 	int i;
1453 
1454 	disk_csum = sb->sb_csum;
1455 	sb->sb_csum = 0;
1456 	newcsum = 0;
1457 	for (i=0; size>=4; size -= 4 )
1458 		newcsum += le32_to_cpu(*isuper++);
1459 
1460 	if (size == 2)
1461 		newcsum += le16_to_cpu(*(__le16*) isuper);
1462 
1463 	csum = (newcsum & 0xffffffff) + (newcsum >> 32);
1464 	sb->sb_csum = disk_csum;
1465 	return cpu_to_le32(csum);
1466 }
1467 
1468 static int md_set_badblocks(struct badblocks *bb, sector_t s, int sectors,
1469 			    int acknowledged);
1470 static int super_1_load(struct md_rdev *rdev, struct md_rdev *refdev, int minor_version)
1471 {
1472 	struct mdp_superblock_1 *sb;
1473 	int ret;
1474 	sector_t sb_start;
1475 	char b[BDEVNAME_SIZE], b2[BDEVNAME_SIZE];
1476 	int bmask;
1477 
1478 	/*
1479 	 * Calculate the position of the superblock in 512byte sectors.
1480 	 * It is always aligned to a 4K boundary and
1481 	 * depeding on minor_version, it can be:
1482 	 * 0: At least 8K, but less than 12K, from end of device
1483 	 * 1: At start of device
1484 	 * 2: 4K from start of device.
1485 	 */
1486 	switch(minor_version) {
1487 	case 0:
1488 		sb_start = i_size_read(rdev->bdev->bd_inode) >> 9;
1489 		sb_start -= 8*2;
1490 		sb_start &= ~(sector_t)(4*2-1);
1491 		break;
1492 	case 1:
1493 		sb_start = 0;
1494 		break;
1495 	case 2:
1496 		sb_start = 8;
1497 		break;
1498 	default:
1499 		return -EINVAL;
1500 	}
1501 	rdev->sb_start = sb_start;
1502 
1503 	/* superblock is rarely larger than 1K, but it can be larger,
1504 	 * and it is safe to read 4k, so we do that
1505 	 */
1506 	ret = read_disk_sb(rdev, 4096);
1507 	if (ret) return ret;
1508 
1509 
1510 	sb = page_address(rdev->sb_page);
1511 
1512 	if (sb->magic != cpu_to_le32(MD_SB_MAGIC) ||
1513 	    sb->major_version != cpu_to_le32(1) ||
1514 	    le32_to_cpu(sb->max_dev) > (4096-256)/2 ||
1515 	    le64_to_cpu(sb->super_offset) != rdev->sb_start ||
1516 	    (le32_to_cpu(sb->feature_map) & ~MD_FEATURE_ALL) != 0)
1517 		return -EINVAL;
1518 
1519 	if (calc_sb_1_csum(sb) != sb->sb_csum) {
1520 		printk("md: invalid superblock checksum on %s\n",
1521 			bdevname(rdev->bdev,b));
1522 		return -EINVAL;
1523 	}
1524 	if (le64_to_cpu(sb->data_size) < 10) {
1525 		printk("md: data_size too small on %s\n",
1526 		       bdevname(rdev->bdev,b));
1527 		return -EINVAL;
1528 	}
1529 
1530 	rdev->preferred_minor = 0xffff;
1531 	rdev->data_offset = le64_to_cpu(sb->data_offset);
1532 	atomic_set(&rdev->corrected_errors, le32_to_cpu(sb->cnt_corrected_read));
1533 
1534 	rdev->sb_size = le32_to_cpu(sb->max_dev) * 2 + 256;
1535 	bmask = queue_logical_block_size(rdev->bdev->bd_disk->queue)-1;
1536 	if (rdev->sb_size & bmask)
1537 		rdev->sb_size = (rdev->sb_size | bmask) + 1;
1538 
1539 	if (minor_version
1540 	    && rdev->data_offset < sb_start + (rdev->sb_size/512))
1541 		return -EINVAL;
1542 
1543 	if (sb->level == cpu_to_le32(LEVEL_MULTIPATH))
1544 		rdev->desc_nr = -1;
1545 	else
1546 		rdev->desc_nr = le32_to_cpu(sb->dev_number);
1547 
1548 	if (!rdev->bb_page) {
1549 		rdev->bb_page = alloc_page(GFP_KERNEL);
1550 		if (!rdev->bb_page)
1551 			return -ENOMEM;
1552 	}
1553 	if ((le32_to_cpu(sb->feature_map) & MD_FEATURE_BAD_BLOCKS) &&
1554 	    rdev->badblocks.count == 0) {
1555 		/* need to load the bad block list.
1556 		 * Currently we limit it to one page.
1557 		 */
1558 		s32 offset;
1559 		sector_t bb_sector;
1560 		u64 *bbp;
1561 		int i;
1562 		int sectors = le16_to_cpu(sb->bblog_size);
1563 		if (sectors > (PAGE_SIZE / 512))
1564 			return -EINVAL;
1565 		offset = le32_to_cpu(sb->bblog_offset);
1566 		if (offset == 0)
1567 			return -EINVAL;
1568 		bb_sector = (long long)offset;
1569 		if (!sync_page_io(rdev, bb_sector, sectors << 9,
1570 				  rdev->bb_page, READ, true))
1571 			return -EIO;
1572 		bbp = (u64 *)page_address(rdev->bb_page);
1573 		rdev->badblocks.shift = sb->bblog_shift;
1574 		for (i = 0 ; i < (sectors << (9-3)) ; i++, bbp++) {
1575 			u64 bb = le64_to_cpu(*bbp);
1576 			int count = bb & (0x3ff);
1577 			u64 sector = bb >> 10;
1578 			sector <<= sb->bblog_shift;
1579 			count <<= sb->bblog_shift;
1580 			if (bb + 1 == 0)
1581 				break;
1582 			if (md_set_badblocks(&rdev->badblocks,
1583 					     sector, count, 1) == 0)
1584 				return -EINVAL;
1585 		}
1586 	} else if (sb->bblog_offset == 0)
1587 		rdev->badblocks.shift = -1;
1588 
1589 	if (!refdev) {
1590 		ret = 1;
1591 	} else {
1592 		__u64 ev1, ev2;
1593 		struct mdp_superblock_1 *refsb = page_address(refdev->sb_page);
1594 
1595 		if (memcmp(sb->set_uuid, refsb->set_uuid, 16) != 0 ||
1596 		    sb->level != refsb->level ||
1597 		    sb->layout != refsb->layout ||
1598 		    sb->chunksize != refsb->chunksize) {
1599 			printk(KERN_WARNING "md: %s has strangely different"
1600 				" superblock to %s\n",
1601 				bdevname(rdev->bdev,b),
1602 				bdevname(refdev->bdev,b2));
1603 			return -EINVAL;
1604 		}
1605 		ev1 = le64_to_cpu(sb->events);
1606 		ev2 = le64_to_cpu(refsb->events);
1607 
1608 		if (ev1 > ev2)
1609 			ret = 1;
1610 		else
1611 			ret = 0;
1612 	}
1613 	if (minor_version)
1614 		rdev->sectors = (i_size_read(rdev->bdev->bd_inode) >> 9) -
1615 			le64_to_cpu(sb->data_offset);
1616 	else
1617 		rdev->sectors = rdev->sb_start;
1618 	if (rdev->sectors < le64_to_cpu(sb->data_size))
1619 		return -EINVAL;
1620 	rdev->sectors = le64_to_cpu(sb->data_size);
1621 	if (le64_to_cpu(sb->size) > rdev->sectors)
1622 		return -EINVAL;
1623 	return ret;
1624 }
1625 
1626 static int super_1_validate(struct mddev *mddev, struct md_rdev *rdev)
1627 {
1628 	struct mdp_superblock_1 *sb = page_address(rdev->sb_page);
1629 	__u64 ev1 = le64_to_cpu(sb->events);
1630 
1631 	rdev->raid_disk = -1;
1632 	clear_bit(Faulty, &rdev->flags);
1633 	clear_bit(In_sync, &rdev->flags);
1634 	clear_bit(WriteMostly, &rdev->flags);
1635 
1636 	if (mddev->raid_disks == 0) {
1637 		mddev->major_version = 1;
1638 		mddev->patch_version = 0;
1639 		mddev->external = 0;
1640 		mddev->chunk_sectors = le32_to_cpu(sb->chunksize);
1641 		mddev->ctime = le64_to_cpu(sb->ctime) & ((1ULL << 32)-1);
1642 		mddev->utime = le64_to_cpu(sb->utime) & ((1ULL << 32)-1);
1643 		mddev->level = le32_to_cpu(sb->level);
1644 		mddev->clevel[0] = 0;
1645 		mddev->layout = le32_to_cpu(sb->layout);
1646 		mddev->raid_disks = le32_to_cpu(sb->raid_disks);
1647 		mddev->dev_sectors = le64_to_cpu(sb->size);
1648 		mddev->events = ev1;
1649 		mddev->bitmap_info.offset = 0;
1650 		mddev->bitmap_info.default_offset = 1024 >> 9;
1651 
1652 		mddev->recovery_cp = le64_to_cpu(sb->resync_offset);
1653 		memcpy(mddev->uuid, sb->set_uuid, 16);
1654 
1655 		mddev->max_disks =  (4096-256)/2;
1656 
1657 		if ((le32_to_cpu(sb->feature_map) & MD_FEATURE_BITMAP_OFFSET) &&
1658 		    mddev->bitmap_info.file == NULL )
1659 			mddev->bitmap_info.offset =
1660 				(__s32)le32_to_cpu(sb->bitmap_offset);
1661 
1662 		if ((le32_to_cpu(sb->feature_map) & MD_FEATURE_RESHAPE_ACTIVE)) {
1663 			mddev->reshape_position = le64_to_cpu(sb->reshape_position);
1664 			mddev->delta_disks = le32_to_cpu(sb->delta_disks);
1665 			mddev->new_level = le32_to_cpu(sb->new_level);
1666 			mddev->new_layout = le32_to_cpu(sb->new_layout);
1667 			mddev->new_chunk_sectors = le32_to_cpu(sb->new_chunk);
1668 		} else {
1669 			mddev->reshape_position = MaxSector;
1670 			mddev->delta_disks = 0;
1671 			mddev->new_level = mddev->level;
1672 			mddev->new_layout = mddev->layout;
1673 			mddev->new_chunk_sectors = mddev->chunk_sectors;
1674 		}
1675 
1676 	} else if (mddev->pers == NULL) {
1677 		/* Insist of good event counter while assembling, except for
1678 		 * spares (which don't need an event count) */
1679 		++ev1;
1680 		if (rdev->desc_nr >= 0 &&
1681 		    rdev->desc_nr < le32_to_cpu(sb->max_dev) &&
1682 		    le16_to_cpu(sb->dev_roles[rdev->desc_nr]) < 0xfffe)
1683 			if (ev1 < mddev->events)
1684 				return -EINVAL;
1685 	} else if (mddev->bitmap) {
1686 		/* If adding to array with a bitmap, then we can accept an
1687 		 * older device, but not too old.
1688 		 */
1689 		if (ev1 < mddev->bitmap->events_cleared)
1690 			return 0;
1691 	} else {
1692 		if (ev1 < mddev->events)
1693 			/* just a hot-add of a new device, leave raid_disk at -1 */
1694 			return 0;
1695 	}
1696 	if (mddev->level != LEVEL_MULTIPATH) {
1697 		int role;
1698 		if (rdev->desc_nr < 0 ||
1699 		    rdev->desc_nr >= le32_to_cpu(sb->max_dev)) {
1700 			role = 0xffff;
1701 			rdev->desc_nr = -1;
1702 		} else
1703 			role = le16_to_cpu(sb->dev_roles[rdev->desc_nr]);
1704 		switch(role) {
1705 		case 0xffff: /* spare */
1706 			break;
1707 		case 0xfffe: /* faulty */
1708 			set_bit(Faulty, &rdev->flags);
1709 			break;
1710 		default:
1711 			if ((le32_to_cpu(sb->feature_map) &
1712 			     MD_FEATURE_RECOVERY_OFFSET))
1713 				rdev->recovery_offset = le64_to_cpu(sb->recovery_offset);
1714 			else
1715 				set_bit(In_sync, &rdev->flags);
1716 			rdev->raid_disk = role;
1717 			break;
1718 		}
1719 		if (sb->devflags & WriteMostly1)
1720 			set_bit(WriteMostly, &rdev->flags);
1721 	} else /* MULTIPATH are always insync */
1722 		set_bit(In_sync, &rdev->flags);
1723 
1724 	return 0;
1725 }
1726 
1727 static void super_1_sync(struct mddev *mddev, struct md_rdev *rdev)
1728 {
1729 	struct mdp_superblock_1 *sb;
1730 	struct md_rdev *rdev2;
1731 	int max_dev, i;
1732 	/* make rdev->sb match mddev and rdev data. */
1733 
1734 	sb = page_address(rdev->sb_page);
1735 
1736 	sb->feature_map = 0;
1737 	sb->pad0 = 0;
1738 	sb->recovery_offset = cpu_to_le64(0);
1739 	memset(sb->pad1, 0, sizeof(sb->pad1));
1740 	memset(sb->pad3, 0, sizeof(sb->pad3));
1741 
1742 	sb->utime = cpu_to_le64((__u64)mddev->utime);
1743 	sb->events = cpu_to_le64(mddev->events);
1744 	if (mddev->in_sync)
1745 		sb->resync_offset = cpu_to_le64(mddev->recovery_cp);
1746 	else
1747 		sb->resync_offset = cpu_to_le64(0);
1748 
1749 	sb->cnt_corrected_read = cpu_to_le32(atomic_read(&rdev->corrected_errors));
1750 
1751 	sb->raid_disks = cpu_to_le32(mddev->raid_disks);
1752 	sb->size = cpu_to_le64(mddev->dev_sectors);
1753 	sb->chunksize = cpu_to_le32(mddev->chunk_sectors);
1754 	sb->level = cpu_to_le32(mddev->level);
1755 	sb->layout = cpu_to_le32(mddev->layout);
1756 
1757 	if (test_bit(WriteMostly, &rdev->flags))
1758 		sb->devflags |= WriteMostly1;
1759 	else
1760 		sb->devflags &= ~WriteMostly1;
1761 
1762 	if (mddev->bitmap && mddev->bitmap_info.file == NULL) {
1763 		sb->bitmap_offset = cpu_to_le32((__u32)mddev->bitmap_info.offset);
1764 		sb->feature_map = cpu_to_le32(MD_FEATURE_BITMAP_OFFSET);
1765 	}
1766 
1767 	if (rdev->raid_disk >= 0 &&
1768 	    !test_bit(In_sync, &rdev->flags)) {
1769 		sb->feature_map |=
1770 			cpu_to_le32(MD_FEATURE_RECOVERY_OFFSET);
1771 		sb->recovery_offset =
1772 			cpu_to_le64(rdev->recovery_offset);
1773 	}
1774 
1775 	if (mddev->reshape_position != MaxSector) {
1776 		sb->feature_map |= cpu_to_le32(MD_FEATURE_RESHAPE_ACTIVE);
1777 		sb->reshape_position = cpu_to_le64(mddev->reshape_position);
1778 		sb->new_layout = cpu_to_le32(mddev->new_layout);
1779 		sb->delta_disks = cpu_to_le32(mddev->delta_disks);
1780 		sb->new_level = cpu_to_le32(mddev->new_level);
1781 		sb->new_chunk = cpu_to_le32(mddev->new_chunk_sectors);
1782 	}
1783 
1784 	if (rdev->badblocks.count == 0)
1785 		/* Nothing to do for bad blocks*/ ;
1786 	else if (sb->bblog_offset == 0)
1787 		/* Cannot record bad blocks on this device */
1788 		md_error(mddev, rdev);
1789 	else {
1790 		struct badblocks *bb = &rdev->badblocks;
1791 		u64 *bbp = (u64 *)page_address(rdev->bb_page);
1792 		u64 *p = bb->page;
1793 		sb->feature_map |= cpu_to_le32(MD_FEATURE_BAD_BLOCKS);
1794 		if (bb->changed) {
1795 			unsigned seq;
1796 
1797 retry:
1798 			seq = read_seqbegin(&bb->lock);
1799 
1800 			memset(bbp, 0xff, PAGE_SIZE);
1801 
1802 			for (i = 0 ; i < bb->count ; i++) {
1803 				u64 internal_bb = *p++;
1804 				u64 store_bb = ((BB_OFFSET(internal_bb) << 10)
1805 						| BB_LEN(internal_bb));
1806 				*bbp++ = cpu_to_le64(store_bb);
1807 			}
1808 			if (read_seqretry(&bb->lock, seq))
1809 				goto retry;
1810 
1811 			bb->sector = (rdev->sb_start +
1812 				      (int)le32_to_cpu(sb->bblog_offset));
1813 			bb->size = le16_to_cpu(sb->bblog_size);
1814 			bb->changed = 0;
1815 		}
1816 	}
1817 
1818 	max_dev = 0;
1819 	list_for_each_entry(rdev2, &mddev->disks, same_set)
1820 		if (rdev2->desc_nr+1 > max_dev)
1821 			max_dev = rdev2->desc_nr+1;
1822 
1823 	if (max_dev > le32_to_cpu(sb->max_dev)) {
1824 		int bmask;
1825 		sb->max_dev = cpu_to_le32(max_dev);
1826 		rdev->sb_size = max_dev * 2 + 256;
1827 		bmask = queue_logical_block_size(rdev->bdev->bd_disk->queue)-1;
1828 		if (rdev->sb_size & bmask)
1829 			rdev->sb_size = (rdev->sb_size | bmask) + 1;
1830 	} else
1831 		max_dev = le32_to_cpu(sb->max_dev);
1832 
1833 	for (i=0; i<max_dev;i++)
1834 		sb->dev_roles[i] = cpu_to_le16(0xfffe);
1835 
1836 	list_for_each_entry(rdev2, &mddev->disks, same_set) {
1837 		i = rdev2->desc_nr;
1838 		if (test_bit(Faulty, &rdev2->flags))
1839 			sb->dev_roles[i] = cpu_to_le16(0xfffe);
1840 		else if (test_bit(In_sync, &rdev2->flags))
1841 			sb->dev_roles[i] = cpu_to_le16(rdev2->raid_disk);
1842 		else if (rdev2->raid_disk >= 0)
1843 			sb->dev_roles[i] = cpu_to_le16(rdev2->raid_disk);
1844 		else
1845 			sb->dev_roles[i] = cpu_to_le16(0xffff);
1846 	}
1847 
1848 	sb->sb_csum = calc_sb_1_csum(sb);
1849 }
1850 
1851 static unsigned long long
1852 super_1_rdev_size_change(struct md_rdev *rdev, sector_t num_sectors)
1853 {
1854 	struct mdp_superblock_1 *sb;
1855 	sector_t max_sectors;
1856 	if (num_sectors && num_sectors < rdev->mddev->dev_sectors)
1857 		return 0; /* component must fit device */
1858 	if (rdev->sb_start < rdev->data_offset) {
1859 		/* minor versions 1 and 2; superblock before data */
1860 		max_sectors = i_size_read(rdev->bdev->bd_inode) >> 9;
1861 		max_sectors -= rdev->data_offset;
1862 		if (!num_sectors || num_sectors > max_sectors)
1863 			num_sectors = max_sectors;
1864 	} else if (rdev->mddev->bitmap_info.offset) {
1865 		/* minor version 0 with bitmap we can't move */
1866 		return 0;
1867 	} else {
1868 		/* minor version 0; superblock after data */
1869 		sector_t sb_start;
1870 		sb_start = (i_size_read(rdev->bdev->bd_inode) >> 9) - 8*2;
1871 		sb_start &= ~(sector_t)(4*2 - 1);
1872 		max_sectors = rdev->sectors + sb_start - rdev->sb_start;
1873 		if (!num_sectors || num_sectors > max_sectors)
1874 			num_sectors = max_sectors;
1875 		rdev->sb_start = sb_start;
1876 	}
1877 	sb = page_address(rdev->sb_page);
1878 	sb->data_size = cpu_to_le64(num_sectors);
1879 	sb->super_offset = rdev->sb_start;
1880 	sb->sb_csum = calc_sb_1_csum(sb);
1881 	md_super_write(rdev->mddev, rdev, rdev->sb_start, rdev->sb_size,
1882 		       rdev->sb_page);
1883 	md_super_wait(rdev->mddev);
1884 	return num_sectors;
1885 }
1886 
1887 static struct super_type super_types[] = {
1888 	[0] = {
1889 		.name	= "0.90.0",
1890 		.owner	= THIS_MODULE,
1891 		.load_super	    = super_90_load,
1892 		.validate_super	    = super_90_validate,
1893 		.sync_super	    = super_90_sync,
1894 		.rdev_size_change   = super_90_rdev_size_change,
1895 	},
1896 	[1] = {
1897 		.name	= "md-1",
1898 		.owner	= THIS_MODULE,
1899 		.load_super	    = super_1_load,
1900 		.validate_super	    = super_1_validate,
1901 		.sync_super	    = super_1_sync,
1902 		.rdev_size_change   = super_1_rdev_size_change,
1903 	},
1904 };
1905 
1906 static void sync_super(struct mddev *mddev, struct md_rdev *rdev)
1907 {
1908 	if (mddev->sync_super) {
1909 		mddev->sync_super(mddev, rdev);
1910 		return;
1911 	}
1912 
1913 	BUG_ON(mddev->major_version >= ARRAY_SIZE(super_types));
1914 
1915 	super_types[mddev->major_version].sync_super(mddev, rdev);
1916 }
1917 
1918 static int match_mddev_units(struct mddev *mddev1, struct mddev *mddev2)
1919 {
1920 	struct md_rdev *rdev, *rdev2;
1921 
1922 	rcu_read_lock();
1923 	rdev_for_each_rcu(rdev, mddev1)
1924 		rdev_for_each_rcu(rdev2, mddev2)
1925 			if (rdev->bdev->bd_contains ==
1926 			    rdev2->bdev->bd_contains) {
1927 				rcu_read_unlock();
1928 				return 1;
1929 			}
1930 	rcu_read_unlock();
1931 	return 0;
1932 }
1933 
1934 static LIST_HEAD(pending_raid_disks);
1935 
1936 /*
1937  * Try to register data integrity profile for an mddev
1938  *
1939  * This is called when an array is started and after a disk has been kicked
1940  * from the array. It only succeeds if all working and active component devices
1941  * are integrity capable with matching profiles.
1942  */
1943 int md_integrity_register(struct mddev *mddev)
1944 {
1945 	struct md_rdev *rdev, *reference = NULL;
1946 
1947 	if (list_empty(&mddev->disks))
1948 		return 0; /* nothing to do */
1949 	if (!mddev->gendisk || blk_get_integrity(mddev->gendisk))
1950 		return 0; /* shouldn't register, or already is */
1951 	list_for_each_entry(rdev, &mddev->disks, same_set) {
1952 		/* skip spares and non-functional disks */
1953 		if (test_bit(Faulty, &rdev->flags))
1954 			continue;
1955 		if (rdev->raid_disk < 0)
1956 			continue;
1957 		if (!reference) {
1958 			/* Use the first rdev as the reference */
1959 			reference = rdev;
1960 			continue;
1961 		}
1962 		/* does this rdev's profile match the reference profile? */
1963 		if (blk_integrity_compare(reference->bdev->bd_disk,
1964 				rdev->bdev->bd_disk) < 0)
1965 			return -EINVAL;
1966 	}
1967 	if (!reference || !bdev_get_integrity(reference->bdev))
1968 		return 0;
1969 	/*
1970 	 * All component devices are integrity capable and have matching
1971 	 * profiles, register the common profile for the md device.
1972 	 */
1973 	if (blk_integrity_register(mddev->gendisk,
1974 			bdev_get_integrity(reference->bdev)) != 0) {
1975 		printk(KERN_ERR "md: failed to register integrity for %s\n",
1976 			mdname(mddev));
1977 		return -EINVAL;
1978 	}
1979 	printk(KERN_NOTICE "md: data integrity enabled on %s\n", mdname(mddev));
1980 	if (bioset_integrity_create(mddev->bio_set, BIO_POOL_SIZE)) {
1981 		printk(KERN_ERR "md: failed to create integrity pool for %s\n",
1982 		       mdname(mddev));
1983 		return -EINVAL;
1984 	}
1985 	return 0;
1986 }
1987 EXPORT_SYMBOL(md_integrity_register);
1988 
1989 /* Disable data integrity if non-capable/non-matching disk is being added */
1990 void md_integrity_add_rdev(struct md_rdev *rdev, struct mddev *mddev)
1991 {
1992 	struct blk_integrity *bi_rdev = bdev_get_integrity(rdev->bdev);
1993 	struct blk_integrity *bi_mddev = blk_get_integrity(mddev->gendisk);
1994 
1995 	if (!bi_mddev) /* nothing to do */
1996 		return;
1997 	if (rdev->raid_disk < 0) /* skip spares */
1998 		return;
1999 	if (bi_rdev && blk_integrity_compare(mddev->gendisk,
2000 					     rdev->bdev->bd_disk) >= 0)
2001 		return;
2002 	printk(KERN_NOTICE "disabling data integrity on %s\n", mdname(mddev));
2003 	blk_integrity_unregister(mddev->gendisk);
2004 }
2005 EXPORT_SYMBOL(md_integrity_add_rdev);
2006 
2007 static int bind_rdev_to_array(struct md_rdev * rdev, struct mddev * mddev)
2008 {
2009 	char b[BDEVNAME_SIZE];
2010 	struct kobject *ko;
2011 	char *s;
2012 	int err;
2013 
2014 	if (rdev->mddev) {
2015 		MD_BUG();
2016 		return -EINVAL;
2017 	}
2018 
2019 	/* prevent duplicates */
2020 	if (find_rdev(mddev, rdev->bdev->bd_dev))
2021 		return -EEXIST;
2022 
2023 	/* make sure rdev->sectors exceeds mddev->dev_sectors */
2024 	if (rdev->sectors && (mddev->dev_sectors == 0 ||
2025 			rdev->sectors < mddev->dev_sectors)) {
2026 		if (mddev->pers) {
2027 			/* Cannot change size, so fail
2028 			 * If mddev->level <= 0, then we don't care
2029 			 * about aligning sizes (e.g. linear)
2030 			 */
2031 			if (mddev->level > 0)
2032 				return -ENOSPC;
2033 		} else
2034 			mddev->dev_sectors = rdev->sectors;
2035 	}
2036 
2037 	/* Verify rdev->desc_nr is unique.
2038 	 * If it is -1, assign a free number, else
2039 	 * check number is not in use
2040 	 */
2041 	if (rdev->desc_nr < 0) {
2042 		int choice = 0;
2043 		if (mddev->pers) choice = mddev->raid_disks;
2044 		while (find_rdev_nr(mddev, choice))
2045 			choice++;
2046 		rdev->desc_nr = choice;
2047 	} else {
2048 		if (find_rdev_nr(mddev, rdev->desc_nr))
2049 			return -EBUSY;
2050 	}
2051 	if (mddev->max_disks && rdev->desc_nr >= mddev->max_disks) {
2052 		printk(KERN_WARNING "md: %s: array is limited to %d devices\n",
2053 		       mdname(mddev), mddev->max_disks);
2054 		return -EBUSY;
2055 	}
2056 	bdevname(rdev->bdev,b);
2057 	while ( (s=strchr(b, '/')) != NULL)
2058 		*s = '!';
2059 
2060 	rdev->mddev = mddev;
2061 	printk(KERN_INFO "md: bind<%s>\n", b);
2062 
2063 	if ((err = kobject_add(&rdev->kobj, &mddev->kobj, "dev-%s", b)))
2064 		goto fail;
2065 
2066 	ko = &part_to_dev(rdev->bdev->bd_part)->kobj;
2067 	if (sysfs_create_link(&rdev->kobj, ko, "block"))
2068 		/* failure here is OK */;
2069 	rdev->sysfs_state = sysfs_get_dirent_safe(rdev->kobj.sd, "state");
2070 
2071 	list_add_rcu(&rdev->same_set, &mddev->disks);
2072 	bd_link_disk_holder(rdev->bdev, mddev->gendisk);
2073 
2074 	/* May as well allow recovery to be retried once */
2075 	mddev->recovery_disabled++;
2076 
2077 	return 0;
2078 
2079  fail:
2080 	printk(KERN_WARNING "md: failed to register dev-%s for %s\n",
2081 	       b, mdname(mddev));
2082 	return err;
2083 }
2084 
2085 static void md_delayed_delete(struct work_struct *ws)
2086 {
2087 	struct md_rdev *rdev = container_of(ws, struct md_rdev, del_work);
2088 	kobject_del(&rdev->kobj);
2089 	kobject_put(&rdev->kobj);
2090 }
2091 
2092 static void unbind_rdev_from_array(struct md_rdev * rdev)
2093 {
2094 	char b[BDEVNAME_SIZE];
2095 	if (!rdev->mddev) {
2096 		MD_BUG();
2097 		return;
2098 	}
2099 	bd_unlink_disk_holder(rdev->bdev, rdev->mddev->gendisk);
2100 	list_del_rcu(&rdev->same_set);
2101 	printk(KERN_INFO "md: unbind<%s>\n", bdevname(rdev->bdev,b));
2102 	rdev->mddev = NULL;
2103 	sysfs_remove_link(&rdev->kobj, "block");
2104 	sysfs_put(rdev->sysfs_state);
2105 	rdev->sysfs_state = NULL;
2106 	kfree(rdev->badblocks.page);
2107 	rdev->badblocks.count = 0;
2108 	rdev->badblocks.page = NULL;
2109 	/* We need to delay this, otherwise we can deadlock when
2110 	 * writing to 'remove' to "dev/state".  We also need
2111 	 * to delay it due to rcu usage.
2112 	 */
2113 	synchronize_rcu();
2114 	INIT_WORK(&rdev->del_work, md_delayed_delete);
2115 	kobject_get(&rdev->kobj);
2116 	queue_work(md_misc_wq, &rdev->del_work);
2117 }
2118 
2119 /*
2120  * prevent the device from being mounted, repartitioned or
2121  * otherwise reused by a RAID array (or any other kernel
2122  * subsystem), by bd_claiming the device.
2123  */
2124 static int lock_rdev(struct md_rdev *rdev, dev_t dev, int shared)
2125 {
2126 	int err = 0;
2127 	struct block_device *bdev;
2128 	char b[BDEVNAME_SIZE];
2129 
2130 	bdev = blkdev_get_by_dev(dev, FMODE_READ|FMODE_WRITE|FMODE_EXCL,
2131 				 shared ? (struct md_rdev *)lock_rdev : rdev);
2132 	if (IS_ERR(bdev)) {
2133 		printk(KERN_ERR "md: could not open %s.\n",
2134 			__bdevname(dev, b));
2135 		return PTR_ERR(bdev);
2136 	}
2137 	rdev->bdev = bdev;
2138 	return err;
2139 }
2140 
2141 static void unlock_rdev(struct md_rdev *rdev)
2142 {
2143 	struct block_device *bdev = rdev->bdev;
2144 	rdev->bdev = NULL;
2145 	if (!bdev)
2146 		MD_BUG();
2147 	blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
2148 }
2149 
2150 void md_autodetect_dev(dev_t dev);
2151 
2152 static void export_rdev(struct md_rdev * rdev)
2153 {
2154 	char b[BDEVNAME_SIZE];
2155 	printk(KERN_INFO "md: export_rdev(%s)\n",
2156 		bdevname(rdev->bdev,b));
2157 	if (rdev->mddev)
2158 		MD_BUG();
2159 	free_disk_sb(rdev);
2160 #ifndef MODULE
2161 	if (test_bit(AutoDetected, &rdev->flags))
2162 		md_autodetect_dev(rdev->bdev->bd_dev);
2163 #endif
2164 	unlock_rdev(rdev);
2165 	kobject_put(&rdev->kobj);
2166 }
2167 
2168 static void kick_rdev_from_array(struct md_rdev * rdev)
2169 {
2170 	unbind_rdev_from_array(rdev);
2171 	export_rdev(rdev);
2172 }
2173 
2174 static void export_array(struct mddev *mddev)
2175 {
2176 	struct md_rdev *rdev, *tmp;
2177 
2178 	rdev_for_each(rdev, tmp, mddev) {
2179 		if (!rdev->mddev) {
2180 			MD_BUG();
2181 			continue;
2182 		}
2183 		kick_rdev_from_array(rdev);
2184 	}
2185 	if (!list_empty(&mddev->disks))
2186 		MD_BUG();
2187 	mddev->raid_disks = 0;
2188 	mddev->major_version = 0;
2189 }
2190 
2191 static void print_desc(mdp_disk_t *desc)
2192 {
2193 	printk(" DISK<N:%d,(%d,%d),R:%d,S:%d>\n", desc->number,
2194 		desc->major,desc->minor,desc->raid_disk,desc->state);
2195 }
2196 
2197 static void print_sb_90(mdp_super_t *sb)
2198 {
2199 	int i;
2200 
2201 	printk(KERN_INFO
2202 		"md:  SB: (V:%d.%d.%d) ID:<%08x.%08x.%08x.%08x> CT:%08x\n",
2203 		sb->major_version, sb->minor_version, sb->patch_version,
2204 		sb->set_uuid0, sb->set_uuid1, sb->set_uuid2, sb->set_uuid3,
2205 		sb->ctime);
2206 	printk(KERN_INFO "md:     L%d S%08d ND:%d RD:%d md%d LO:%d CS:%d\n",
2207 		sb->level, sb->size, sb->nr_disks, sb->raid_disks,
2208 		sb->md_minor, sb->layout, sb->chunk_size);
2209 	printk(KERN_INFO "md:     UT:%08x ST:%d AD:%d WD:%d"
2210 		" FD:%d SD:%d CSUM:%08x E:%08lx\n",
2211 		sb->utime, sb->state, sb->active_disks, sb->working_disks,
2212 		sb->failed_disks, sb->spare_disks,
2213 		sb->sb_csum, (unsigned long)sb->events_lo);
2214 
2215 	printk(KERN_INFO);
2216 	for (i = 0; i < MD_SB_DISKS; i++) {
2217 		mdp_disk_t *desc;
2218 
2219 		desc = sb->disks + i;
2220 		if (desc->number || desc->major || desc->minor ||
2221 		    desc->raid_disk || (desc->state && (desc->state != 4))) {
2222 			printk("     D %2d: ", i);
2223 			print_desc(desc);
2224 		}
2225 	}
2226 	printk(KERN_INFO "md:     THIS: ");
2227 	print_desc(&sb->this_disk);
2228 }
2229 
2230 static void print_sb_1(struct mdp_superblock_1 *sb)
2231 {
2232 	__u8 *uuid;
2233 
2234 	uuid = sb->set_uuid;
2235 	printk(KERN_INFO
2236 	       "md:  SB: (V:%u) (F:0x%08x) Array-ID:<%pU>\n"
2237 	       "md:    Name: \"%s\" CT:%llu\n",
2238 		le32_to_cpu(sb->major_version),
2239 		le32_to_cpu(sb->feature_map),
2240 		uuid,
2241 		sb->set_name,
2242 		(unsigned long long)le64_to_cpu(sb->ctime)
2243 		       & MD_SUPERBLOCK_1_TIME_SEC_MASK);
2244 
2245 	uuid = sb->device_uuid;
2246 	printk(KERN_INFO
2247 	       "md:       L%u SZ%llu RD:%u LO:%u CS:%u DO:%llu DS:%llu SO:%llu"
2248 			" RO:%llu\n"
2249 	       "md:     Dev:%08x UUID: %pU\n"
2250 	       "md:       (F:0x%08x) UT:%llu Events:%llu ResyncOffset:%llu CSUM:0x%08x\n"
2251 	       "md:         (MaxDev:%u) \n",
2252 		le32_to_cpu(sb->level),
2253 		(unsigned long long)le64_to_cpu(sb->size),
2254 		le32_to_cpu(sb->raid_disks),
2255 		le32_to_cpu(sb->layout),
2256 		le32_to_cpu(sb->chunksize),
2257 		(unsigned long long)le64_to_cpu(sb->data_offset),
2258 		(unsigned long long)le64_to_cpu(sb->data_size),
2259 		(unsigned long long)le64_to_cpu(sb->super_offset),
2260 		(unsigned long long)le64_to_cpu(sb->recovery_offset),
2261 		le32_to_cpu(sb->dev_number),
2262 		uuid,
2263 		sb->devflags,
2264 		(unsigned long long)le64_to_cpu(sb->utime) & MD_SUPERBLOCK_1_TIME_SEC_MASK,
2265 		(unsigned long long)le64_to_cpu(sb->events),
2266 		(unsigned long long)le64_to_cpu(sb->resync_offset),
2267 		le32_to_cpu(sb->sb_csum),
2268 		le32_to_cpu(sb->max_dev)
2269 		);
2270 }
2271 
2272 static void print_rdev(struct md_rdev *rdev, int major_version)
2273 {
2274 	char b[BDEVNAME_SIZE];
2275 	printk(KERN_INFO "md: rdev %s, Sect:%08llu F:%d S:%d DN:%u\n",
2276 		bdevname(rdev->bdev, b), (unsigned long long)rdev->sectors,
2277 	        test_bit(Faulty, &rdev->flags), test_bit(In_sync, &rdev->flags),
2278 	        rdev->desc_nr);
2279 	if (rdev->sb_loaded) {
2280 		printk(KERN_INFO "md: rdev superblock (MJ:%d):\n", major_version);
2281 		switch (major_version) {
2282 		case 0:
2283 			print_sb_90(page_address(rdev->sb_page));
2284 			break;
2285 		case 1:
2286 			print_sb_1(page_address(rdev->sb_page));
2287 			break;
2288 		}
2289 	} else
2290 		printk(KERN_INFO "md: no rdev superblock!\n");
2291 }
2292 
2293 static void md_print_devices(void)
2294 {
2295 	struct list_head *tmp;
2296 	struct md_rdev *rdev;
2297 	struct mddev *mddev;
2298 	char b[BDEVNAME_SIZE];
2299 
2300 	printk("\n");
2301 	printk("md:	**********************************\n");
2302 	printk("md:	* <COMPLETE RAID STATE PRINTOUT> *\n");
2303 	printk("md:	**********************************\n");
2304 	for_each_mddev(mddev, tmp) {
2305 
2306 		if (mddev->bitmap)
2307 			bitmap_print_sb(mddev->bitmap);
2308 		else
2309 			printk("%s: ", mdname(mddev));
2310 		list_for_each_entry(rdev, &mddev->disks, same_set)
2311 			printk("<%s>", bdevname(rdev->bdev,b));
2312 		printk("\n");
2313 
2314 		list_for_each_entry(rdev, &mddev->disks, same_set)
2315 			print_rdev(rdev, mddev->major_version);
2316 	}
2317 	printk("md:	**********************************\n");
2318 	printk("\n");
2319 }
2320 
2321 
2322 static void sync_sbs(struct mddev * mddev, int nospares)
2323 {
2324 	/* Update each superblock (in-memory image), but
2325 	 * if we are allowed to, skip spares which already
2326 	 * have the right event counter, or have one earlier
2327 	 * (which would mean they aren't being marked as dirty
2328 	 * with the rest of the array)
2329 	 */
2330 	struct md_rdev *rdev;
2331 	list_for_each_entry(rdev, &mddev->disks, same_set) {
2332 		if (rdev->sb_events == mddev->events ||
2333 		    (nospares &&
2334 		     rdev->raid_disk < 0 &&
2335 		     rdev->sb_events+1 == mddev->events)) {
2336 			/* Don't update this superblock */
2337 			rdev->sb_loaded = 2;
2338 		} else {
2339 			sync_super(mddev, rdev);
2340 			rdev->sb_loaded = 1;
2341 		}
2342 	}
2343 }
2344 
2345 static void md_update_sb(struct mddev * mddev, int force_change)
2346 {
2347 	struct md_rdev *rdev;
2348 	int sync_req;
2349 	int nospares = 0;
2350 	int any_badblocks_changed = 0;
2351 
2352 repeat:
2353 	/* First make sure individual recovery_offsets are correct */
2354 	list_for_each_entry(rdev, &mddev->disks, same_set) {
2355 		if (rdev->raid_disk >= 0 &&
2356 		    mddev->delta_disks >= 0 &&
2357 		    !test_bit(In_sync, &rdev->flags) &&
2358 		    mddev->curr_resync_completed > rdev->recovery_offset)
2359 				rdev->recovery_offset = mddev->curr_resync_completed;
2360 
2361 	}
2362 	if (!mddev->persistent) {
2363 		clear_bit(MD_CHANGE_CLEAN, &mddev->flags);
2364 		clear_bit(MD_CHANGE_DEVS, &mddev->flags);
2365 		if (!mddev->external) {
2366 			clear_bit(MD_CHANGE_PENDING, &mddev->flags);
2367 			list_for_each_entry(rdev, &mddev->disks, same_set) {
2368 				if (rdev->badblocks.changed) {
2369 					md_ack_all_badblocks(&rdev->badblocks);
2370 					md_error(mddev, rdev);
2371 				}
2372 				clear_bit(Blocked, &rdev->flags);
2373 				clear_bit(BlockedBadBlocks, &rdev->flags);
2374 				wake_up(&rdev->blocked_wait);
2375 			}
2376 		}
2377 		wake_up(&mddev->sb_wait);
2378 		return;
2379 	}
2380 
2381 	spin_lock_irq(&mddev->write_lock);
2382 
2383 	mddev->utime = get_seconds();
2384 
2385 	if (test_and_clear_bit(MD_CHANGE_DEVS, &mddev->flags))
2386 		force_change = 1;
2387 	if (test_and_clear_bit(MD_CHANGE_CLEAN, &mddev->flags))
2388 		/* just a clean<-> dirty transition, possibly leave spares alone,
2389 		 * though if events isn't the right even/odd, we will have to do
2390 		 * spares after all
2391 		 */
2392 		nospares = 1;
2393 	if (force_change)
2394 		nospares = 0;
2395 	if (mddev->degraded)
2396 		/* If the array is degraded, then skipping spares is both
2397 		 * dangerous and fairly pointless.
2398 		 * Dangerous because a device that was removed from the array
2399 		 * might have a event_count that still looks up-to-date,
2400 		 * so it can be re-added without a resync.
2401 		 * Pointless because if there are any spares to skip,
2402 		 * then a recovery will happen and soon that array won't
2403 		 * be degraded any more and the spare can go back to sleep then.
2404 		 */
2405 		nospares = 0;
2406 
2407 	sync_req = mddev->in_sync;
2408 
2409 	/* If this is just a dirty<->clean transition, and the array is clean
2410 	 * and 'events' is odd, we can roll back to the previous clean state */
2411 	if (nospares
2412 	    && (mddev->in_sync && mddev->recovery_cp == MaxSector)
2413 	    && mddev->can_decrease_events
2414 	    && mddev->events != 1) {
2415 		mddev->events--;
2416 		mddev->can_decrease_events = 0;
2417 	} else {
2418 		/* otherwise we have to go forward and ... */
2419 		mddev->events ++;
2420 		mddev->can_decrease_events = nospares;
2421 	}
2422 
2423 	if (!mddev->events) {
2424 		/*
2425 		 * oops, this 64-bit counter should never wrap.
2426 		 * Either we are in around ~1 trillion A.C., assuming
2427 		 * 1 reboot per second, or we have a bug:
2428 		 */
2429 		MD_BUG();
2430 		mddev->events --;
2431 	}
2432 
2433 	list_for_each_entry(rdev, &mddev->disks, same_set) {
2434 		if (rdev->badblocks.changed)
2435 			any_badblocks_changed++;
2436 		if (test_bit(Faulty, &rdev->flags))
2437 			set_bit(FaultRecorded, &rdev->flags);
2438 	}
2439 
2440 	sync_sbs(mddev, nospares);
2441 	spin_unlock_irq(&mddev->write_lock);
2442 
2443 	pr_debug("md: updating %s RAID superblock on device (in sync %d)\n",
2444 		 mdname(mddev), mddev->in_sync);
2445 
2446 	bitmap_update_sb(mddev->bitmap);
2447 	list_for_each_entry(rdev, &mddev->disks, same_set) {
2448 		char b[BDEVNAME_SIZE];
2449 
2450 		if (rdev->sb_loaded != 1)
2451 			continue; /* no noise on spare devices */
2452 
2453 		if (!test_bit(Faulty, &rdev->flags) &&
2454 		    rdev->saved_raid_disk == -1) {
2455 			md_super_write(mddev,rdev,
2456 				       rdev->sb_start, rdev->sb_size,
2457 				       rdev->sb_page);
2458 			pr_debug("md: (write) %s's sb offset: %llu\n",
2459 				 bdevname(rdev->bdev, b),
2460 				 (unsigned long long)rdev->sb_start);
2461 			rdev->sb_events = mddev->events;
2462 			if (rdev->badblocks.size) {
2463 				md_super_write(mddev, rdev,
2464 					       rdev->badblocks.sector,
2465 					       rdev->badblocks.size << 9,
2466 					       rdev->bb_page);
2467 				rdev->badblocks.size = 0;
2468 			}
2469 
2470 		} else if (test_bit(Faulty, &rdev->flags))
2471 			pr_debug("md: %s (skipping faulty)\n",
2472 				 bdevname(rdev->bdev, b));
2473 		else
2474 			pr_debug("(skipping incremental s/r ");
2475 
2476 		if (mddev->level == LEVEL_MULTIPATH)
2477 			/* only need to write one superblock... */
2478 			break;
2479 	}
2480 	md_super_wait(mddev);
2481 	/* if there was a failure, MD_CHANGE_DEVS was set, and we re-write super */
2482 
2483 	spin_lock_irq(&mddev->write_lock);
2484 	if (mddev->in_sync != sync_req ||
2485 	    test_bit(MD_CHANGE_DEVS, &mddev->flags)) {
2486 		/* have to write it out again */
2487 		spin_unlock_irq(&mddev->write_lock);
2488 		goto repeat;
2489 	}
2490 	clear_bit(MD_CHANGE_PENDING, &mddev->flags);
2491 	spin_unlock_irq(&mddev->write_lock);
2492 	wake_up(&mddev->sb_wait);
2493 	if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
2494 		sysfs_notify(&mddev->kobj, NULL, "sync_completed");
2495 
2496 	list_for_each_entry(rdev, &mddev->disks, same_set) {
2497 		if (test_and_clear_bit(FaultRecorded, &rdev->flags))
2498 			clear_bit(Blocked, &rdev->flags);
2499 
2500 		if (any_badblocks_changed)
2501 			md_ack_all_badblocks(&rdev->badblocks);
2502 		clear_bit(BlockedBadBlocks, &rdev->flags);
2503 		wake_up(&rdev->blocked_wait);
2504 	}
2505 }
2506 
2507 /* words written to sysfs files may, or may not, be \n terminated.
2508  * We want to accept with case. For this we use cmd_match.
2509  */
2510 static int cmd_match(const char *cmd, const char *str)
2511 {
2512 	/* See if cmd, written into a sysfs file, matches
2513 	 * str.  They must either be the same, or cmd can
2514 	 * have a trailing newline
2515 	 */
2516 	while (*cmd && *str && *cmd == *str) {
2517 		cmd++;
2518 		str++;
2519 	}
2520 	if (*cmd == '\n')
2521 		cmd++;
2522 	if (*str || *cmd)
2523 		return 0;
2524 	return 1;
2525 }
2526 
2527 struct rdev_sysfs_entry {
2528 	struct attribute attr;
2529 	ssize_t (*show)(struct md_rdev *, char *);
2530 	ssize_t (*store)(struct md_rdev *, const char *, size_t);
2531 };
2532 
2533 static ssize_t
2534 state_show(struct md_rdev *rdev, char *page)
2535 {
2536 	char *sep = "";
2537 	size_t len = 0;
2538 
2539 	if (test_bit(Faulty, &rdev->flags) ||
2540 	    rdev->badblocks.unacked_exist) {
2541 		len+= sprintf(page+len, "%sfaulty",sep);
2542 		sep = ",";
2543 	}
2544 	if (test_bit(In_sync, &rdev->flags)) {
2545 		len += sprintf(page+len, "%sin_sync",sep);
2546 		sep = ",";
2547 	}
2548 	if (test_bit(WriteMostly, &rdev->flags)) {
2549 		len += sprintf(page+len, "%swrite_mostly",sep);
2550 		sep = ",";
2551 	}
2552 	if (test_bit(Blocked, &rdev->flags) ||
2553 	    rdev->badblocks.unacked_exist) {
2554 		len += sprintf(page+len, "%sblocked", sep);
2555 		sep = ",";
2556 	}
2557 	if (!test_bit(Faulty, &rdev->flags) &&
2558 	    !test_bit(In_sync, &rdev->flags)) {
2559 		len += sprintf(page+len, "%sspare", sep);
2560 		sep = ",";
2561 	}
2562 	if (test_bit(WriteErrorSeen, &rdev->flags)) {
2563 		len += sprintf(page+len, "%swrite_error", sep);
2564 		sep = ",";
2565 	}
2566 	return len+sprintf(page+len, "\n");
2567 }
2568 
2569 static ssize_t
2570 state_store(struct md_rdev *rdev, const char *buf, size_t len)
2571 {
2572 	/* can write
2573 	 *  faulty  - simulates an error
2574 	 *  remove  - disconnects the device
2575 	 *  writemostly - sets write_mostly
2576 	 *  -writemostly - clears write_mostly
2577 	 *  blocked - sets the Blocked flags
2578 	 *  -blocked - clears the Blocked and possibly simulates an error
2579 	 *  insync - sets Insync providing device isn't active
2580 	 *  write_error - sets WriteErrorSeen
2581 	 *  -write_error - clears WriteErrorSeen
2582 	 */
2583 	int err = -EINVAL;
2584 	if (cmd_match(buf, "faulty") && rdev->mddev->pers) {
2585 		md_error(rdev->mddev, rdev);
2586 		if (test_bit(Faulty, &rdev->flags))
2587 			err = 0;
2588 		else
2589 			err = -EBUSY;
2590 	} else if (cmd_match(buf, "remove")) {
2591 		if (rdev->raid_disk >= 0)
2592 			err = -EBUSY;
2593 		else {
2594 			struct mddev *mddev = rdev->mddev;
2595 			kick_rdev_from_array(rdev);
2596 			if (mddev->pers)
2597 				md_update_sb(mddev, 1);
2598 			md_new_event(mddev);
2599 			err = 0;
2600 		}
2601 	} else if (cmd_match(buf, "writemostly")) {
2602 		set_bit(WriteMostly, &rdev->flags);
2603 		err = 0;
2604 	} else if (cmd_match(buf, "-writemostly")) {
2605 		clear_bit(WriteMostly, &rdev->flags);
2606 		err = 0;
2607 	} else if (cmd_match(buf, "blocked")) {
2608 		set_bit(Blocked, &rdev->flags);
2609 		err = 0;
2610 	} else if (cmd_match(buf, "-blocked")) {
2611 		if (!test_bit(Faulty, &rdev->flags) &&
2612 		    rdev->badblocks.unacked_exist) {
2613 			/* metadata handler doesn't understand badblocks,
2614 			 * so we need to fail the device
2615 			 */
2616 			md_error(rdev->mddev, rdev);
2617 		}
2618 		clear_bit(Blocked, &rdev->flags);
2619 		clear_bit(BlockedBadBlocks, &rdev->flags);
2620 		wake_up(&rdev->blocked_wait);
2621 		set_bit(MD_RECOVERY_NEEDED, &rdev->mddev->recovery);
2622 		md_wakeup_thread(rdev->mddev->thread);
2623 
2624 		err = 0;
2625 	} else if (cmd_match(buf, "insync") && rdev->raid_disk == -1) {
2626 		set_bit(In_sync, &rdev->flags);
2627 		err = 0;
2628 	} else if (cmd_match(buf, "write_error")) {
2629 		set_bit(WriteErrorSeen, &rdev->flags);
2630 		err = 0;
2631 	} else if (cmd_match(buf, "-write_error")) {
2632 		clear_bit(WriteErrorSeen, &rdev->flags);
2633 		err = 0;
2634 	}
2635 	if (!err)
2636 		sysfs_notify_dirent_safe(rdev->sysfs_state);
2637 	return err ? err : len;
2638 }
2639 static struct rdev_sysfs_entry rdev_state =
2640 __ATTR(state, S_IRUGO|S_IWUSR, state_show, state_store);
2641 
2642 static ssize_t
2643 errors_show(struct md_rdev *rdev, char *page)
2644 {
2645 	return sprintf(page, "%d\n", atomic_read(&rdev->corrected_errors));
2646 }
2647 
2648 static ssize_t
2649 errors_store(struct md_rdev *rdev, const char *buf, size_t len)
2650 {
2651 	char *e;
2652 	unsigned long n = simple_strtoul(buf, &e, 10);
2653 	if (*buf && (*e == 0 || *e == '\n')) {
2654 		atomic_set(&rdev->corrected_errors, n);
2655 		return len;
2656 	}
2657 	return -EINVAL;
2658 }
2659 static struct rdev_sysfs_entry rdev_errors =
2660 __ATTR(errors, S_IRUGO|S_IWUSR, errors_show, errors_store);
2661 
2662 static ssize_t
2663 slot_show(struct md_rdev *rdev, char *page)
2664 {
2665 	if (rdev->raid_disk < 0)
2666 		return sprintf(page, "none\n");
2667 	else
2668 		return sprintf(page, "%d\n", rdev->raid_disk);
2669 }
2670 
2671 static ssize_t
2672 slot_store(struct md_rdev *rdev, const char *buf, size_t len)
2673 {
2674 	char *e;
2675 	int err;
2676 	int slot = simple_strtoul(buf, &e, 10);
2677 	if (strncmp(buf, "none", 4)==0)
2678 		slot = -1;
2679 	else if (e==buf || (*e && *e!= '\n'))
2680 		return -EINVAL;
2681 	if (rdev->mddev->pers && slot == -1) {
2682 		/* Setting 'slot' on an active array requires also
2683 		 * updating the 'rd%d' link, and communicating
2684 		 * with the personality with ->hot_*_disk.
2685 		 * For now we only support removing
2686 		 * failed/spare devices.  This normally happens automatically,
2687 		 * but not when the metadata is externally managed.
2688 		 */
2689 		if (rdev->raid_disk == -1)
2690 			return -EEXIST;
2691 		/* personality does all needed checks */
2692 		if (rdev->mddev->pers->hot_remove_disk == NULL)
2693 			return -EINVAL;
2694 		err = rdev->mddev->pers->
2695 			hot_remove_disk(rdev->mddev, rdev->raid_disk);
2696 		if (err)
2697 			return err;
2698 		sysfs_unlink_rdev(rdev->mddev, rdev);
2699 		rdev->raid_disk = -1;
2700 		set_bit(MD_RECOVERY_NEEDED, &rdev->mddev->recovery);
2701 		md_wakeup_thread(rdev->mddev->thread);
2702 	} else if (rdev->mddev->pers) {
2703 		struct md_rdev *rdev2;
2704 		/* Activating a spare .. or possibly reactivating
2705 		 * if we ever get bitmaps working here.
2706 		 */
2707 
2708 		if (rdev->raid_disk != -1)
2709 			return -EBUSY;
2710 
2711 		if (test_bit(MD_RECOVERY_RUNNING, &rdev->mddev->recovery))
2712 			return -EBUSY;
2713 
2714 		if (rdev->mddev->pers->hot_add_disk == NULL)
2715 			return -EINVAL;
2716 
2717 		list_for_each_entry(rdev2, &rdev->mddev->disks, same_set)
2718 			if (rdev2->raid_disk == slot)
2719 				return -EEXIST;
2720 
2721 		if (slot >= rdev->mddev->raid_disks &&
2722 		    slot >= rdev->mddev->raid_disks + rdev->mddev->delta_disks)
2723 			return -ENOSPC;
2724 
2725 		rdev->raid_disk = slot;
2726 		if (test_bit(In_sync, &rdev->flags))
2727 			rdev->saved_raid_disk = slot;
2728 		else
2729 			rdev->saved_raid_disk = -1;
2730 		clear_bit(In_sync, &rdev->flags);
2731 		err = rdev->mddev->pers->
2732 			hot_add_disk(rdev->mddev, rdev);
2733 		if (err) {
2734 			rdev->raid_disk = -1;
2735 			return err;
2736 		} else
2737 			sysfs_notify_dirent_safe(rdev->sysfs_state);
2738 		if (sysfs_link_rdev(rdev->mddev, rdev))
2739 			/* failure here is OK */;
2740 		/* don't wakeup anyone, leave that to userspace. */
2741 	} else {
2742 		if (slot >= rdev->mddev->raid_disks &&
2743 		    slot >= rdev->mddev->raid_disks + rdev->mddev->delta_disks)
2744 			return -ENOSPC;
2745 		rdev->raid_disk = slot;
2746 		/* assume it is working */
2747 		clear_bit(Faulty, &rdev->flags);
2748 		clear_bit(WriteMostly, &rdev->flags);
2749 		set_bit(In_sync, &rdev->flags);
2750 		sysfs_notify_dirent_safe(rdev->sysfs_state);
2751 	}
2752 	return len;
2753 }
2754 
2755 
2756 static struct rdev_sysfs_entry rdev_slot =
2757 __ATTR(slot, S_IRUGO|S_IWUSR, slot_show, slot_store);
2758 
2759 static ssize_t
2760 offset_show(struct md_rdev *rdev, char *page)
2761 {
2762 	return sprintf(page, "%llu\n", (unsigned long long)rdev->data_offset);
2763 }
2764 
2765 static ssize_t
2766 offset_store(struct md_rdev *rdev, const char *buf, size_t len)
2767 {
2768 	char *e;
2769 	unsigned long long offset = simple_strtoull(buf, &e, 10);
2770 	if (e==buf || (*e && *e != '\n'))
2771 		return -EINVAL;
2772 	if (rdev->mddev->pers && rdev->raid_disk >= 0)
2773 		return -EBUSY;
2774 	if (rdev->sectors && rdev->mddev->external)
2775 		/* Must set offset before size, so overlap checks
2776 		 * can be sane */
2777 		return -EBUSY;
2778 	rdev->data_offset = offset;
2779 	return len;
2780 }
2781 
2782 static struct rdev_sysfs_entry rdev_offset =
2783 __ATTR(offset, S_IRUGO|S_IWUSR, offset_show, offset_store);
2784 
2785 static ssize_t
2786 rdev_size_show(struct md_rdev *rdev, char *page)
2787 {
2788 	return sprintf(page, "%llu\n", (unsigned long long)rdev->sectors / 2);
2789 }
2790 
2791 static int overlaps(sector_t s1, sector_t l1, sector_t s2, sector_t l2)
2792 {
2793 	/* check if two start/length pairs overlap */
2794 	if (s1+l1 <= s2)
2795 		return 0;
2796 	if (s2+l2 <= s1)
2797 		return 0;
2798 	return 1;
2799 }
2800 
2801 static int strict_blocks_to_sectors(const char *buf, sector_t *sectors)
2802 {
2803 	unsigned long long blocks;
2804 	sector_t new;
2805 
2806 	if (strict_strtoull(buf, 10, &blocks) < 0)
2807 		return -EINVAL;
2808 
2809 	if (blocks & 1ULL << (8 * sizeof(blocks) - 1))
2810 		return -EINVAL; /* sector conversion overflow */
2811 
2812 	new = blocks * 2;
2813 	if (new != blocks * 2)
2814 		return -EINVAL; /* unsigned long long to sector_t overflow */
2815 
2816 	*sectors = new;
2817 	return 0;
2818 }
2819 
2820 static ssize_t
2821 rdev_size_store(struct md_rdev *rdev, const char *buf, size_t len)
2822 {
2823 	struct mddev *my_mddev = rdev->mddev;
2824 	sector_t oldsectors = rdev->sectors;
2825 	sector_t sectors;
2826 
2827 	if (strict_blocks_to_sectors(buf, &sectors) < 0)
2828 		return -EINVAL;
2829 	if (my_mddev->pers && rdev->raid_disk >= 0) {
2830 		if (my_mddev->persistent) {
2831 			sectors = super_types[my_mddev->major_version].
2832 				rdev_size_change(rdev, sectors);
2833 			if (!sectors)
2834 				return -EBUSY;
2835 		} else if (!sectors)
2836 			sectors = (i_size_read(rdev->bdev->bd_inode) >> 9) -
2837 				rdev->data_offset;
2838 	}
2839 	if (sectors < my_mddev->dev_sectors)
2840 		return -EINVAL; /* component must fit device */
2841 
2842 	rdev->sectors = sectors;
2843 	if (sectors > oldsectors && my_mddev->external) {
2844 		/* need to check that all other rdevs with the same ->bdev
2845 		 * do not overlap.  We need to unlock the mddev to avoid
2846 		 * a deadlock.  We have already changed rdev->sectors, and if
2847 		 * we have to change it back, we will have the lock again.
2848 		 */
2849 		struct mddev *mddev;
2850 		int overlap = 0;
2851 		struct list_head *tmp;
2852 
2853 		mddev_unlock(my_mddev);
2854 		for_each_mddev(mddev, tmp) {
2855 			struct md_rdev *rdev2;
2856 
2857 			mddev_lock(mddev);
2858 			list_for_each_entry(rdev2, &mddev->disks, same_set)
2859 				if (rdev->bdev == rdev2->bdev &&
2860 				    rdev != rdev2 &&
2861 				    overlaps(rdev->data_offset, rdev->sectors,
2862 					     rdev2->data_offset,
2863 					     rdev2->sectors)) {
2864 					overlap = 1;
2865 					break;
2866 				}
2867 			mddev_unlock(mddev);
2868 			if (overlap) {
2869 				mddev_put(mddev);
2870 				break;
2871 			}
2872 		}
2873 		mddev_lock(my_mddev);
2874 		if (overlap) {
2875 			/* Someone else could have slipped in a size
2876 			 * change here, but doing so is just silly.
2877 			 * We put oldsectors back because we *know* it is
2878 			 * safe, and trust userspace not to race with
2879 			 * itself
2880 			 */
2881 			rdev->sectors = oldsectors;
2882 			return -EBUSY;
2883 		}
2884 	}
2885 	return len;
2886 }
2887 
2888 static struct rdev_sysfs_entry rdev_size =
2889 __ATTR(size, S_IRUGO|S_IWUSR, rdev_size_show, rdev_size_store);
2890 
2891 
2892 static ssize_t recovery_start_show(struct md_rdev *rdev, char *page)
2893 {
2894 	unsigned long long recovery_start = rdev->recovery_offset;
2895 
2896 	if (test_bit(In_sync, &rdev->flags) ||
2897 	    recovery_start == MaxSector)
2898 		return sprintf(page, "none\n");
2899 
2900 	return sprintf(page, "%llu\n", recovery_start);
2901 }
2902 
2903 static ssize_t recovery_start_store(struct md_rdev *rdev, const char *buf, size_t len)
2904 {
2905 	unsigned long long recovery_start;
2906 
2907 	if (cmd_match(buf, "none"))
2908 		recovery_start = MaxSector;
2909 	else if (strict_strtoull(buf, 10, &recovery_start))
2910 		return -EINVAL;
2911 
2912 	if (rdev->mddev->pers &&
2913 	    rdev->raid_disk >= 0)
2914 		return -EBUSY;
2915 
2916 	rdev->recovery_offset = recovery_start;
2917 	if (recovery_start == MaxSector)
2918 		set_bit(In_sync, &rdev->flags);
2919 	else
2920 		clear_bit(In_sync, &rdev->flags);
2921 	return len;
2922 }
2923 
2924 static struct rdev_sysfs_entry rdev_recovery_start =
2925 __ATTR(recovery_start, S_IRUGO|S_IWUSR, recovery_start_show, recovery_start_store);
2926 
2927 
2928 static ssize_t
2929 badblocks_show(struct badblocks *bb, char *page, int unack);
2930 static ssize_t
2931 badblocks_store(struct badblocks *bb, const char *page, size_t len, int unack);
2932 
2933 static ssize_t bb_show(struct md_rdev *rdev, char *page)
2934 {
2935 	return badblocks_show(&rdev->badblocks, page, 0);
2936 }
2937 static ssize_t bb_store(struct md_rdev *rdev, const char *page, size_t len)
2938 {
2939 	int rv = badblocks_store(&rdev->badblocks, page, len, 0);
2940 	/* Maybe that ack was all we needed */
2941 	if (test_and_clear_bit(BlockedBadBlocks, &rdev->flags))
2942 		wake_up(&rdev->blocked_wait);
2943 	return rv;
2944 }
2945 static struct rdev_sysfs_entry rdev_bad_blocks =
2946 __ATTR(bad_blocks, S_IRUGO|S_IWUSR, bb_show, bb_store);
2947 
2948 
2949 static ssize_t ubb_show(struct md_rdev *rdev, char *page)
2950 {
2951 	return badblocks_show(&rdev->badblocks, page, 1);
2952 }
2953 static ssize_t ubb_store(struct md_rdev *rdev, const char *page, size_t len)
2954 {
2955 	return badblocks_store(&rdev->badblocks, page, len, 1);
2956 }
2957 static struct rdev_sysfs_entry rdev_unack_bad_blocks =
2958 __ATTR(unacknowledged_bad_blocks, S_IRUGO|S_IWUSR, ubb_show, ubb_store);
2959 
2960 static struct attribute *rdev_default_attrs[] = {
2961 	&rdev_state.attr,
2962 	&rdev_errors.attr,
2963 	&rdev_slot.attr,
2964 	&rdev_offset.attr,
2965 	&rdev_size.attr,
2966 	&rdev_recovery_start.attr,
2967 	&rdev_bad_blocks.attr,
2968 	&rdev_unack_bad_blocks.attr,
2969 	NULL,
2970 };
2971 static ssize_t
2972 rdev_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
2973 {
2974 	struct rdev_sysfs_entry *entry = container_of(attr, struct rdev_sysfs_entry, attr);
2975 	struct md_rdev *rdev = container_of(kobj, struct md_rdev, kobj);
2976 	struct mddev *mddev = rdev->mddev;
2977 	ssize_t rv;
2978 
2979 	if (!entry->show)
2980 		return -EIO;
2981 
2982 	rv = mddev ? mddev_lock(mddev) : -EBUSY;
2983 	if (!rv) {
2984 		if (rdev->mddev == NULL)
2985 			rv = -EBUSY;
2986 		else
2987 			rv = entry->show(rdev, page);
2988 		mddev_unlock(mddev);
2989 	}
2990 	return rv;
2991 }
2992 
2993 static ssize_t
2994 rdev_attr_store(struct kobject *kobj, struct attribute *attr,
2995 	      const char *page, size_t length)
2996 {
2997 	struct rdev_sysfs_entry *entry = container_of(attr, struct rdev_sysfs_entry, attr);
2998 	struct md_rdev *rdev = container_of(kobj, struct md_rdev, kobj);
2999 	ssize_t rv;
3000 	struct mddev *mddev = rdev->mddev;
3001 
3002 	if (!entry->store)
3003 		return -EIO;
3004 	if (!capable(CAP_SYS_ADMIN))
3005 		return -EACCES;
3006 	rv = mddev ? mddev_lock(mddev): -EBUSY;
3007 	if (!rv) {
3008 		if (rdev->mddev == NULL)
3009 			rv = -EBUSY;
3010 		else
3011 			rv = entry->store(rdev, page, length);
3012 		mddev_unlock(mddev);
3013 	}
3014 	return rv;
3015 }
3016 
3017 static void rdev_free(struct kobject *ko)
3018 {
3019 	struct md_rdev *rdev = container_of(ko, struct md_rdev, kobj);
3020 	kfree(rdev);
3021 }
3022 static const struct sysfs_ops rdev_sysfs_ops = {
3023 	.show		= rdev_attr_show,
3024 	.store		= rdev_attr_store,
3025 };
3026 static struct kobj_type rdev_ktype = {
3027 	.release	= rdev_free,
3028 	.sysfs_ops	= &rdev_sysfs_ops,
3029 	.default_attrs	= rdev_default_attrs,
3030 };
3031 
3032 int md_rdev_init(struct md_rdev *rdev)
3033 {
3034 	rdev->desc_nr = -1;
3035 	rdev->saved_raid_disk = -1;
3036 	rdev->raid_disk = -1;
3037 	rdev->flags = 0;
3038 	rdev->data_offset = 0;
3039 	rdev->sb_events = 0;
3040 	rdev->last_read_error.tv_sec  = 0;
3041 	rdev->last_read_error.tv_nsec = 0;
3042 	rdev->sb_loaded = 0;
3043 	rdev->bb_page = NULL;
3044 	atomic_set(&rdev->nr_pending, 0);
3045 	atomic_set(&rdev->read_errors, 0);
3046 	atomic_set(&rdev->corrected_errors, 0);
3047 
3048 	INIT_LIST_HEAD(&rdev->same_set);
3049 	init_waitqueue_head(&rdev->blocked_wait);
3050 
3051 	/* Add space to store bad block list.
3052 	 * This reserves the space even on arrays where it cannot
3053 	 * be used - I wonder if that matters
3054 	 */
3055 	rdev->badblocks.count = 0;
3056 	rdev->badblocks.shift = 0;
3057 	rdev->badblocks.page = kmalloc(PAGE_SIZE, GFP_KERNEL);
3058 	seqlock_init(&rdev->badblocks.lock);
3059 	if (rdev->badblocks.page == NULL)
3060 		return -ENOMEM;
3061 
3062 	return 0;
3063 }
3064 EXPORT_SYMBOL_GPL(md_rdev_init);
3065 /*
3066  * Import a device. If 'super_format' >= 0, then sanity check the superblock
3067  *
3068  * mark the device faulty if:
3069  *
3070  *   - the device is nonexistent (zero size)
3071  *   - the device has no valid superblock
3072  *
3073  * a faulty rdev _never_ has rdev->sb set.
3074  */
3075 static struct md_rdev *md_import_device(dev_t newdev, int super_format, int super_minor)
3076 {
3077 	char b[BDEVNAME_SIZE];
3078 	int err;
3079 	struct md_rdev *rdev;
3080 	sector_t size;
3081 
3082 	rdev = kzalloc(sizeof(*rdev), GFP_KERNEL);
3083 	if (!rdev) {
3084 		printk(KERN_ERR "md: could not alloc mem for new device!\n");
3085 		return ERR_PTR(-ENOMEM);
3086 	}
3087 
3088 	err = md_rdev_init(rdev);
3089 	if (err)
3090 		goto abort_free;
3091 	err = alloc_disk_sb(rdev);
3092 	if (err)
3093 		goto abort_free;
3094 
3095 	err = lock_rdev(rdev, newdev, super_format == -2);
3096 	if (err)
3097 		goto abort_free;
3098 
3099 	kobject_init(&rdev->kobj, &rdev_ktype);
3100 
3101 	size = i_size_read(rdev->bdev->bd_inode) >> BLOCK_SIZE_BITS;
3102 	if (!size) {
3103 		printk(KERN_WARNING
3104 			"md: %s has zero or unknown size, marking faulty!\n",
3105 			bdevname(rdev->bdev,b));
3106 		err = -EINVAL;
3107 		goto abort_free;
3108 	}
3109 
3110 	if (super_format >= 0) {
3111 		err = super_types[super_format].
3112 			load_super(rdev, NULL, super_minor);
3113 		if (err == -EINVAL) {
3114 			printk(KERN_WARNING
3115 				"md: %s does not have a valid v%d.%d "
3116 			       "superblock, not importing!\n",
3117 				bdevname(rdev->bdev,b),
3118 			       super_format, super_minor);
3119 			goto abort_free;
3120 		}
3121 		if (err < 0) {
3122 			printk(KERN_WARNING
3123 				"md: could not read %s's sb, not importing!\n",
3124 				bdevname(rdev->bdev,b));
3125 			goto abort_free;
3126 		}
3127 	}
3128 	if (super_format == -1)
3129 		/* hot-add for 0.90, or non-persistent: so no badblocks */
3130 		rdev->badblocks.shift = -1;
3131 
3132 	return rdev;
3133 
3134 abort_free:
3135 	if (rdev->bdev)
3136 		unlock_rdev(rdev);
3137 	free_disk_sb(rdev);
3138 	kfree(rdev->badblocks.page);
3139 	kfree(rdev);
3140 	return ERR_PTR(err);
3141 }
3142 
3143 /*
3144  * Check a full RAID array for plausibility
3145  */
3146 
3147 
3148 static void analyze_sbs(struct mddev * mddev)
3149 {
3150 	int i;
3151 	struct md_rdev *rdev, *freshest, *tmp;
3152 	char b[BDEVNAME_SIZE];
3153 
3154 	freshest = NULL;
3155 	rdev_for_each(rdev, tmp, mddev)
3156 		switch (super_types[mddev->major_version].
3157 			load_super(rdev, freshest, mddev->minor_version)) {
3158 		case 1:
3159 			freshest = rdev;
3160 			break;
3161 		case 0:
3162 			break;
3163 		default:
3164 			printk( KERN_ERR \
3165 				"md: fatal superblock inconsistency in %s"
3166 				" -- removing from array\n",
3167 				bdevname(rdev->bdev,b));
3168 			kick_rdev_from_array(rdev);
3169 		}
3170 
3171 
3172 	super_types[mddev->major_version].
3173 		validate_super(mddev, freshest);
3174 
3175 	i = 0;
3176 	rdev_for_each(rdev, tmp, mddev) {
3177 		if (mddev->max_disks &&
3178 		    (rdev->desc_nr >= mddev->max_disks ||
3179 		     i > mddev->max_disks)) {
3180 			printk(KERN_WARNING
3181 			       "md: %s: %s: only %d devices permitted\n",
3182 			       mdname(mddev), bdevname(rdev->bdev, b),
3183 			       mddev->max_disks);
3184 			kick_rdev_from_array(rdev);
3185 			continue;
3186 		}
3187 		if (rdev != freshest)
3188 			if (super_types[mddev->major_version].
3189 			    validate_super(mddev, rdev)) {
3190 				printk(KERN_WARNING "md: kicking non-fresh %s"
3191 					" from array!\n",
3192 					bdevname(rdev->bdev,b));
3193 				kick_rdev_from_array(rdev);
3194 				continue;
3195 			}
3196 		if (mddev->level == LEVEL_MULTIPATH) {
3197 			rdev->desc_nr = i++;
3198 			rdev->raid_disk = rdev->desc_nr;
3199 			set_bit(In_sync, &rdev->flags);
3200 		} else if (rdev->raid_disk >= (mddev->raid_disks - min(0, mddev->delta_disks))) {
3201 			rdev->raid_disk = -1;
3202 			clear_bit(In_sync, &rdev->flags);
3203 		}
3204 	}
3205 }
3206 
3207 /* Read a fixed-point number.
3208  * Numbers in sysfs attributes should be in "standard" units where
3209  * possible, so time should be in seconds.
3210  * However we internally use a a much smaller unit such as
3211  * milliseconds or jiffies.
3212  * This function takes a decimal number with a possible fractional
3213  * component, and produces an integer which is the result of
3214  * multiplying that number by 10^'scale'.
3215  * all without any floating-point arithmetic.
3216  */
3217 int strict_strtoul_scaled(const char *cp, unsigned long *res, int scale)
3218 {
3219 	unsigned long result = 0;
3220 	long decimals = -1;
3221 	while (isdigit(*cp) || (*cp == '.' && decimals < 0)) {
3222 		if (*cp == '.')
3223 			decimals = 0;
3224 		else if (decimals < scale) {
3225 			unsigned int value;
3226 			value = *cp - '0';
3227 			result = result * 10 + value;
3228 			if (decimals >= 0)
3229 				decimals++;
3230 		}
3231 		cp++;
3232 	}
3233 	if (*cp == '\n')
3234 		cp++;
3235 	if (*cp)
3236 		return -EINVAL;
3237 	if (decimals < 0)
3238 		decimals = 0;
3239 	while (decimals < scale) {
3240 		result *= 10;
3241 		decimals ++;
3242 	}
3243 	*res = result;
3244 	return 0;
3245 }
3246 
3247 
3248 static void md_safemode_timeout(unsigned long data);
3249 
3250 static ssize_t
3251 safe_delay_show(struct mddev *mddev, char *page)
3252 {
3253 	int msec = (mddev->safemode_delay*1000)/HZ;
3254 	return sprintf(page, "%d.%03d\n", msec/1000, msec%1000);
3255 }
3256 static ssize_t
3257 safe_delay_store(struct mddev *mddev, const char *cbuf, size_t len)
3258 {
3259 	unsigned long msec;
3260 
3261 	if (strict_strtoul_scaled(cbuf, &msec, 3) < 0)
3262 		return -EINVAL;
3263 	if (msec == 0)
3264 		mddev->safemode_delay = 0;
3265 	else {
3266 		unsigned long old_delay = mddev->safemode_delay;
3267 		mddev->safemode_delay = (msec*HZ)/1000;
3268 		if (mddev->safemode_delay == 0)
3269 			mddev->safemode_delay = 1;
3270 		if (mddev->safemode_delay < old_delay)
3271 			md_safemode_timeout((unsigned long)mddev);
3272 	}
3273 	return len;
3274 }
3275 static struct md_sysfs_entry md_safe_delay =
3276 __ATTR(safe_mode_delay, S_IRUGO|S_IWUSR,safe_delay_show, safe_delay_store);
3277 
3278 static ssize_t
3279 level_show(struct mddev *mddev, char *page)
3280 {
3281 	struct md_personality *p = mddev->pers;
3282 	if (p)
3283 		return sprintf(page, "%s\n", p->name);
3284 	else if (mddev->clevel[0])
3285 		return sprintf(page, "%s\n", mddev->clevel);
3286 	else if (mddev->level != LEVEL_NONE)
3287 		return sprintf(page, "%d\n", mddev->level);
3288 	else
3289 		return 0;
3290 }
3291 
3292 static ssize_t
3293 level_store(struct mddev *mddev, const char *buf, size_t len)
3294 {
3295 	char clevel[16];
3296 	ssize_t rv = len;
3297 	struct md_personality *pers;
3298 	long level;
3299 	void *priv;
3300 	struct md_rdev *rdev;
3301 
3302 	if (mddev->pers == NULL) {
3303 		if (len == 0)
3304 			return 0;
3305 		if (len >= sizeof(mddev->clevel))
3306 			return -ENOSPC;
3307 		strncpy(mddev->clevel, buf, len);
3308 		if (mddev->clevel[len-1] == '\n')
3309 			len--;
3310 		mddev->clevel[len] = 0;
3311 		mddev->level = LEVEL_NONE;
3312 		return rv;
3313 	}
3314 
3315 	/* request to change the personality.  Need to ensure:
3316 	 *  - array is not engaged in resync/recovery/reshape
3317 	 *  - old personality can be suspended
3318 	 *  - new personality will access other array.
3319 	 */
3320 
3321 	if (mddev->sync_thread ||
3322 	    mddev->reshape_position != MaxSector ||
3323 	    mddev->sysfs_active)
3324 		return -EBUSY;
3325 
3326 	if (!mddev->pers->quiesce) {
3327 		printk(KERN_WARNING "md: %s: %s does not support online personality change\n",
3328 		       mdname(mddev), mddev->pers->name);
3329 		return -EINVAL;
3330 	}
3331 
3332 	/* Now find the new personality */
3333 	if (len == 0 || len >= sizeof(clevel))
3334 		return -EINVAL;
3335 	strncpy(clevel, buf, len);
3336 	if (clevel[len-1] == '\n')
3337 		len--;
3338 	clevel[len] = 0;
3339 	if (strict_strtol(clevel, 10, &level))
3340 		level = LEVEL_NONE;
3341 
3342 	if (request_module("md-%s", clevel) != 0)
3343 		request_module("md-level-%s", clevel);
3344 	spin_lock(&pers_lock);
3345 	pers = find_pers(level, clevel);
3346 	if (!pers || !try_module_get(pers->owner)) {
3347 		spin_unlock(&pers_lock);
3348 		printk(KERN_WARNING "md: personality %s not loaded\n", clevel);
3349 		return -EINVAL;
3350 	}
3351 	spin_unlock(&pers_lock);
3352 
3353 	if (pers == mddev->pers) {
3354 		/* Nothing to do! */
3355 		module_put(pers->owner);
3356 		return rv;
3357 	}
3358 	if (!pers->takeover) {
3359 		module_put(pers->owner);
3360 		printk(KERN_WARNING "md: %s: %s does not support personality takeover\n",
3361 		       mdname(mddev), clevel);
3362 		return -EINVAL;
3363 	}
3364 
3365 	list_for_each_entry(rdev, &mddev->disks, same_set)
3366 		rdev->new_raid_disk = rdev->raid_disk;
3367 
3368 	/* ->takeover must set new_* and/or delta_disks
3369 	 * if it succeeds, and may set them when it fails.
3370 	 */
3371 	priv = pers->takeover(mddev);
3372 	if (IS_ERR(priv)) {
3373 		mddev->new_level = mddev->level;
3374 		mddev->new_layout = mddev->layout;
3375 		mddev->new_chunk_sectors = mddev->chunk_sectors;
3376 		mddev->raid_disks -= mddev->delta_disks;
3377 		mddev->delta_disks = 0;
3378 		module_put(pers->owner);
3379 		printk(KERN_WARNING "md: %s: %s would not accept array\n",
3380 		       mdname(mddev), clevel);
3381 		return PTR_ERR(priv);
3382 	}
3383 
3384 	/* Looks like we have a winner */
3385 	mddev_suspend(mddev);
3386 	mddev->pers->stop(mddev);
3387 
3388 	if (mddev->pers->sync_request == NULL &&
3389 	    pers->sync_request != NULL) {
3390 		/* need to add the md_redundancy_group */
3391 		if (sysfs_create_group(&mddev->kobj, &md_redundancy_group))
3392 			printk(KERN_WARNING
3393 			       "md: cannot register extra attributes for %s\n",
3394 			       mdname(mddev));
3395 		mddev->sysfs_action = sysfs_get_dirent(mddev->kobj.sd, NULL, "sync_action");
3396 	}
3397 	if (mddev->pers->sync_request != NULL &&
3398 	    pers->sync_request == NULL) {
3399 		/* need to remove the md_redundancy_group */
3400 		if (mddev->to_remove == NULL)
3401 			mddev->to_remove = &md_redundancy_group;
3402 	}
3403 
3404 	if (mddev->pers->sync_request == NULL &&
3405 	    mddev->external) {
3406 		/* We are converting from a no-redundancy array
3407 		 * to a redundancy array and metadata is managed
3408 		 * externally so we need to be sure that writes
3409 		 * won't block due to a need to transition
3410 		 *      clean->dirty
3411 		 * until external management is started.
3412 		 */
3413 		mddev->in_sync = 0;
3414 		mddev->safemode_delay = 0;
3415 		mddev->safemode = 0;
3416 	}
3417 
3418 	list_for_each_entry(rdev, &mddev->disks, same_set) {
3419 		if (rdev->raid_disk < 0)
3420 			continue;
3421 		if (rdev->new_raid_disk >= mddev->raid_disks)
3422 			rdev->new_raid_disk = -1;
3423 		if (rdev->new_raid_disk == rdev->raid_disk)
3424 			continue;
3425 		sysfs_unlink_rdev(mddev, rdev);
3426 	}
3427 	list_for_each_entry(rdev, &mddev->disks, same_set) {
3428 		if (rdev->raid_disk < 0)
3429 			continue;
3430 		if (rdev->new_raid_disk == rdev->raid_disk)
3431 			continue;
3432 		rdev->raid_disk = rdev->new_raid_disk;
3433 		if (rdev->raid_disk < 0)
3434 			clear_bit(In_sync, &rdev->flags);
3435 		else {
3436 			if (sysfs_link_rdev(mddev, rdev))
3437 				printk(KERN_WARNING "md: cannot register rd%d"
3438 				       " for %s after level change\n",
3439 				       rdev->raid_disk, mdname(mddev));
3440 		}
3441 	}
3442 
3443 	module_put(mddev->pers->owner);
3444 	mddev->pers = pers;
3445 	mddev->private = priv;
3446 	strlcpy(mddev->clevel, pers->name, sizeof(mddev->clevel));
3447 	mddev->level = mddev->new_level;
3448 	mddev->layout = mddev->new_layout;
3449 	mddev->chunk_sectors = mddev->new_chunk_sectors;
3450 	mddev->delta_disks = 0;
3451 	mddev->degraded = 0;
3452 	if (mddev->pers->sync_request == NULL) {
3453 		/* this is now an array without redundancy, so
3454 		 * it must always be in_sync
3455 		 */
3456 		mddev->in_sync = 1;
3457 		del_timer_sync(&mddev->safemode_timer);
3458 	}
3459 	pers->run(mddev);
3460 	mddev_resume(mddev);
3461 	set_bit(MD_CHANGE_DEVS, &mddev->flags);
3462 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
3463 	md_wakeup_thread(mddev->thread);
3464 	sysfs_notify(&mddev->kobj, NULL, "level");
3465 	md_new_event(mddev);
3466 	return rv;
3467 }
3468 
3469 static struct md_sysfs_entry md_level =
3470 __ATTR(level, S_IRUGO|S_IWUSR, level_show, level_store);
3471 
3472 
3473 static ssize_t
3474 layout_show(struct mddev *mddev, char *page)
3475 {
3476 	/* just a number, not meaningful for all levels */
3477 	if (mddev->reshape_position != MaxSector &&
3478 	    mddev->layout != mddev->new_layout)
3479 		return sprintf(page, "%d (%d)\n",
3480 			       mddev->new_layout, mddev->layout);
3481 	return sprintf(page, "%d\n", mddev->layout);
3482 }
3483 
3484 static ssize_t
3485 layout_store(struct mddev *mddev, const char *buf, size_t len)
3486 {
3487 	char *e;
3488 	unsigned long n = simple_strtoul(buf, &e, 10);
3489 
3490 	if (!*buf || (*e && *e != '\n'))
3491 		return -EINVAL;
3492 
3493 	if (mddev->pers) {
3494 		int err;
3495 		if (mddev->pers->check_reshape == NULL)
3496 			return -EBUSY;
3497 		mddev->new_layout = n;
3498 		err = mddev->pers->check_reshape(mddev);
3499 		if (err) {
3500 			mddev->new_layout = mddev->layout;
3501 			return err;
3502 		}
3503 	} else {
3504 		mddev->new_layout = n;
3505 		if (mddev->reshape_position == MaxSector)
3506 			mddev->layout = n;
3507 	}
3508 	return len;
3509 }
3510 static struct md_sysfs_entry md_layout =
3511 __ATTR(layout, S_IRUGO|S_IWUSR, layout_show, layout_store);
3512 
3513 
3514 static ssize_t
3515 raid_disks_show(struct mddev *mddev, char *page)
3516 {
3517 	if (mddev->raid_disks == 0)
3518 		return 0;
3519 	if (mddev->reshape_position != MaxSector &&
3520 	    mddev->delta_disks != 0)
3521 		return sprintf(page, "%d (%d)\n", mddev->raid_disks,
3522 			       mddev->raid_disks - mddev->delta_disks);
3523 	return sprintf(page, "%d\n", mddev->raid_disks);
3524 }
3525 
3526 static int update_raid_disks(struct mddev *mddev, int raid_disks);
3527 
3528 static ssize_t
3529 raid_disks_store(struct mddev *mddev, const char *buf, size_t len)
3530 {
3531 	char *e;
3532 	int rv = 0;
3533 	unsigned long n = simple_strtoul(buf, &e, 10);
3534 
3535 	if (!*buf || (*e && *e != '\n'))
3536 		return -EINVAL;
3537 
3538 	if (mddev->pers)
3539 		rv = update_raid_disks(mddev, n);
3540 	else if (mddev->reshape_position != MaxSector) {
3541 		int olddisks = mddev->raid_disks - mddev->delta_disks;
3542 		mddev->delta_disks = n - olddisks;
3543 		mddev->raid_disks = n;
3544 	} else
3545 		mddev->raid_disks = n;
3546 	return rv ? rv : len;
3547 }
3548 static struct md_sysfs_entry md_raid_disks =
3549 __ATTR(raid_disks, S_IRUGO|S_IWUSR, raid_disks_show, raid_disks_store);
3550 
3551 static ssize_t
3552 chunk_size_show(struct mddev *mddev, char *page)
3553 {
3554 	if (mddev->reshape_position != MaxSector &&
3555 	    mddev->chunk_sectors != mddev->new_chunk_sectors)
3556 		return sprintf(page, "%d (%d)\n",
3557 			       mddev->new_chunk_sectors << 9,
3558 			       mddev->chunk_sectors << 9);
3559 	return sprintf(page, "%d\n", mddev->chunk_sectors << 9);
3560 }
3561 
3562 static ssize_t
3563 chunk_size_store(struct mddev *mddev, const char *buf, size_t len)
3564 {
3565 	char *e;
3566 	unsigned long n = simple_strtoul(buf, &e, 10);
3567 
3568 	if (!*buf || (*e && *e != '\n'))
3569 		return -EINVAL;
3570 
3571 	if (mddev->pers) {
3572 		int err;
3573 		if (mddev->pers->check_reshape == NULL)
3574 			return -EBUSY;
3575 		mddev->new_chunk_sectors = n >> 9;
3576 		err = mddev->pers->check_reshape(mddev);
3577 		if (err) {
3578 			mddev->new_chunk_sectors = mddev->chunk_sectors;
3579 			return err;
3580 		}
3581 	} else {
3582 		mddev->new_chunk_sectors = n >> 9;
3583 		if (mddev->reshape_position == MaxSector)
3584 			mddev->chunk_sectors = n >> 9;
3585 	}
3586 	return len;
3587 }
3588 static struct md_sysfs_entry md_chunk_size =
3589 __ATTR(chunk_size, S_IRUGO|S_IWUSR, chunk_size_show, chunk_size_store);
3590 
3591 static ssize_t
3592 resync_start_show(struct mddev *mddev, char *page)
3593 {
3594 	if (mddev->recovery_cp == MaxSector)
3595 		return sprintf(page, "none\n");
3596 	return sprintf(page, "%llu\n", (unsigned long long)mddev->recovery_cp);
3597 }
3598 
3599 static ssize_t
3600 resync_start_store(struct mddev *mddev, const char *buf, size_t len)
3601 {
3602 	char *e;
3603 	unsigned long long n = simple_strtoull(buf, &e, 10);
3604 
3605 	if (mddev->pers && !test_bit(MD_RECOVERY_FROZEN, &mddev->recovery))
3606 		return -EBUSY;
3607 	if (cmd_match(buf, "none"))
3608 		n = MaxSector;
3609 	else if (!*buf || (*e && *e != '\n'))
3610 		return -EINVAL;
3611 
3612 	mddev->recovery_cp = n;
3613 	return len;
3614 }
3615 static struct md_sysfs_entry md_resync_start =
3616 __ATTR(resync_start, S_IRUGO|S_IWUSR, resync_start_show, resync_start_store);
3617 
3618 /*
3619  * The array state can be:
3620  *
3621  * clear
3622  *     No devices, no size, no level
3623  *     Equivalent to STOP_ARRAY ioctl
3624  * inactive
3625  *     May have some settings, but array is not active
3626  *        all IO results in error
3627  *     When written, doesn't tear down array, but just stops it
3628  * suspended (not supported yet)
3629  *     All IO requests will block. The array can be reconfigured.
3630  *     Writing this, if accepted, will block until array is quiescent
3631  * readonly
3632  *     no resync can happen.  no superblocks get written.
3633  *     write requests fail
3634  * read-auto
3635  *     like readonly, but behaves like 'clean' on a write request.
3636  *
3637  * clean - no pending writes, but otherwise active.
3638  *     When written to inactive array, starts without resync
3639  *     If a write request arrives then
3640  *       if metadata is known, mark 'dirty' and switch to 'active'.
3641  *       if not known, block and switch to write-pending
3642  *     If written to an active array that has pending writes, then fails.
3643  * active
3644  *     fully active: IO and resync can be happening.
3645  *     When written to inactive array, starts with resync
3646  *
3647  * write-pending
3648  *     clean, but writes are blocked waiting for 'active' to be written.
3649  *
3650  * active-idle
3651  *     like active, but no writes have been seen for a while (100msec).
3652  *
3653  */
3654 enum array_state { clear, inactive, suspended, readonly, read_auto, clean, active,
3655 		   write_pending, active_idle, bad_word};
3656 static char *array_states[] = {
3657 	"clear", "inactive", "suspended", "readonly", "read-auto", "clean", "active",
3658 	"write-pending", "active-idle", NULL };
3659 
3660 static int match_word(const char *word, char **list)
3661 {
3662 	int n;
3663 	for (n=0; list[n]; n++)
3664 		if (cmd_match(word, list[n]))
3665 			break;
3666 	return n;
3667 }
3668 
3669 static ssize_t
3670 array_state_show(struct mddev *mddev, char *page)
3671 {
3672 	enum array_state st = inactive;
3673 
3674 	if (mddev->pers)
3675 		switch(mddev->ro) {
3676 		case 1:
3677 			st = readonly;
3678 			break;
3679 		case 2:
3680 			st = read_auto;
3681 			break;
3682 		case 0:
3683 			if (mddev->in_sync)
3684 				st = clean;
3685 			else if (test_bit(MD_CHANGE_PENDING, &mddev->flags))
3686 				st = write_pending;
3687 			else if (mddev->safemode)
3688 				st = active_idle;
3689 			else
3690 				st = active;
3691 		}
3692 	else {
3693 		if (list_empty(&mddev->disks) &&
3694 		    mddev->raid_disks == 0 &&
3695 		    mddev->dev_sectors == 0)
3696 			st = clear;
3697 		else
3698 			st = inactive;
3699 	}
3700 	return sprintf(page, "%s\n", array_states[st]);
3701 }
3702 
3703 static int do_md_stop(struct mddev * mddev, int ro, int is_open);
3704 static int md_set_readonly(struct mddev * mddev, int is_open);
3705 static int do_md_run(struct mddev * mddev);
3706 static int restart_array(struct mddev *mddev);
3707 
3708 static ssize_t
3709 array_state_store(struct mddev *mddev, const char *buf, size_t len)
3710 {
3711 	int err = -EINVAL;
3712 	enum array_state st = match_word(buf, array_states);
3713 	switch(st) {
3714 	case bad_word:
3715 		break;
3716 	case clear:
3717 		/* stopping an active array */
3718 		if (atomic_read(&mddev->openers) > 0)
3719 			return -EBUSY;
3720 		err = do_md_stop(mddev, 0, 0);
3721 		break;
3722 	case inactive:
3723 		/* stopping an active array */
3724 		if (mddev->pers) {
3725 			if (atomic_read(&mddev->openers) > 0)
3726 				return -EBUSY;
3727 			err = do_md_stop(mddev, 2, 0);
3728 		} else
3729 			err = 0; /* already inactive */
3730 		break;
3731 	case suspended:
3732 		break; /* not supported yet */
3733 	case readonly:
3734 		if (mddev->pers)
3735 			err = md_set_readonly(mddev, 0);
3736 		else {
3737 			mddev->ro = 1;
3738 			set_disk_ro(mddev->gendisk, 1);
3739 			err = do_md_run(mddev);
3740 		}
3741 		break;
3742 	case read_auto:
3743 		if (mddev->pers) {
3744 			if (mddev->ro == 0)
3745 				err = md_set_readonly(mddev, 0);
3746 			else if (mddev->ro == 1)
3747 				err = restart_array(mddev);
3748 			if (err == 0) {
3749 				mddev->ro = 2;
3750 				set_disk_ro(mddev->gendisk, 0);
3751 			}
3752 		} else {
3753 			mddev->ro = 2;
3754 			err = do_md_run(mddev);
3755 		}
3756 		break;
3757 	case clean:
3758 		if (mddev->pers) {
3759 			restart_array(mddev);
3760 			spin_lock_irq(&mddev->write_lock);
3761 			if (atomic_read(&mddev->writes_pending) == 0) {
3762 				if (mddev->in_sync == 0) {
3763 					mddev->in_sync = 1;
3764 					if (mddev->safemode == 1)
3765 						mddev->safemode = 0;
3766 					set_bit(MD_CHANGE_CLEAN, &mddev->flags);
3767 				}
3768 				err = 0;
3769 			} else
3770 				err = -EBUSY;
3771 			spin_unlock_irq(&mddev->write_lock);
3772 		} else
3773 			err = -EINVAL;
3774 		break;
3775 	case active:
3776 		if (mddev->pers) {
3777 			restart_array(mddev);
3778 			clear_bit(MD_CHANGE_PENDING, &mddev->flags);
3779 			wake_up(&mddev->sb_wait);
3780 			err = 0;
3781 		} else {
3782 			mddev->ro = 0;
3783 			set_disk_ro(mddev->gendisk, 0);
3784 			err = do_md_run(mddev);
3785 		}
3786 		break;
3787 	case write_pending:
3788 	case active_idle:
3789 		/* these cannot be set */
3790 		break;
3791 	}
3792 	if (err)
3793 		return err;
3794 	else {
3795 		sysfs_notify_dirent_safe(mddev->sysfs_state);
3796 		return len;
3797 	}
3798 }
3799 static struct md_sysfs_entry md_array_state =
3800 __ATTR(array_state, S_IRUGO|S_IWUSR, array_state_show, array_state_store);
3801 
3802 static ssize_t
3803 max_corrected_read_errors_show(struct mddev *mddev, char *page) {
3804 	return sprintf(page, "%d\n",
3805 		       atomic_read(&mddev->max_corr_read_errors));
3806 }
3807 
3808 static ssize_t
3809 max_corrected_read_errors_store(struct mddev *mddev, const char *buf, size_t len)
3810 {
3811 	char *e;
3812 	unsigned long n = simple_strtoul(buf, &e, 10);
3813 
3814 	if (*buf && (*e == 0 || *e == '\n')) {
3815 		atomic_set(&mddev->max_corr_read_errors, n);
3816 		return len;
3817 	}
3818 	return -EINVAL;
3819 }
3820 
3821 static struct md_sysfs_entry max_corr_read_errors =
3822 __ATTR(max_read_errors, S_IRUGO|S_IWUSR, max_corrected_read_errors_show,
3823 	max_corrected_read_errors_store);
3824 
3825 static ssize_t
3826 null_show(struct mddev *mddev, char *page)
3827 {
3828 	return -EINVAL;
3829 }
3830 
3831 static ssize_t
3832 new_dev_store(struct mddev *mddev, const char *buf, size_t len)
3833 {
3834 	/* buf must be %d:%d\n? giving major and minor numbers */
3835 	/* The new device is added to the array.
3836 	 * If the array has a persistent superblock, we read the
3837 	 * superblock to initialise info and check validity.
3838 	 * Otherwise, only checking done is that in bind_rdev_to_array,
3839 	 * which mainly checks size.
3840 	 */
3841 	char *e;
3842 	int major = simple_strtoul(buf, &e, 10);
3843 	int minor;
3844 	dev_t dev;
3845 	struct md_rdev *rdev;
3846 	int err;
3847 
3848 	if (!*buf || *e != ':' || !e[1] || e[1] == '\n')
3849 		return -EINVAL;
3850 	minor = simple_strtoul(e+1, &e, 10);
3851 	if (*e && *e != '\n')
3852 		return -EINVAL;
3853 	dev = MKDEV(major, minor);
3854 	if (major != MAJOR(dev) ||
3855 	    minor != MINOR(dev))
3856 		return -EOVERFLOW;
3857 
3858 
3859 	if (mddev->persistent) {
3860 		rdev = md_import_device(dev, mddev->major_version,
3861 					mddev->minor_version);
3862 		if (!IS_ERR(rdev) && !list_empty(&mddev->disks)) {
3863 			struct md_rdev *rdev0
3864 				= list_entry(mddev->disks.next,
3865 					     struct md_rdev, same_set);
3866 			err = super_types[mddev->major_version]
3867 				.load_super(rdev, rdev0, mddev->minor_version);
3868 			if (err < 0)
3869 				goto out;
3870 		}
3871 	} else if (mddev->external)
3872 		rdev = md_import_device(dev, -2, -1);
3873 	else
3874 		rdev = md_import_device(dev, -1, -1);
3875 
3876 	if (IS_ERR(rdev))
3877 		return PTR_ERR(rdev);
3878 	err = bind_rdev_to_array(rdev, mddev);
3879  out:
3880 	if (err)
3881 		export_rdev(rdev);
3882 	return err ? err : len;
3883 }
3884 
3885 static struct md_sysfs_entry md_new_device =
3886 __ATTR(new_dev, S_IWUSR, null_show, new_dev_store);
3887 
3888 static ssize_t
3889 bitmap_store(struct mddev *mddev, const char *buf, size_t len)
3890 {
3891 	char *end;
3892 	unsigned long chunk, end_chunk;
3893 
3894 	if (!mddev->bitmap)
3895 		goto out;
3896 	/* buf should be <chunk> <chunk> ... or <chunk>-<chunk> ... (range) */
3897 	while (*buf) {
3898 		chunk = end_chunk = simple_strtoul(buf, &end, 0);
3899 		if (buf == end) break;
3900 		if (*end == '-') { /* range */
3901 			buf = end + 1;
3902 			end_chunk = simple_strtoul(buf, &end, 0);
3903 			if (buf == end) break;
3904 		}
3905 		if (*end && !isspace(*end)) break;
3906 		bitmap_dirty_bits(mddev->bitmap, chunk, end_chunk);
3907 		buf = skip_spaces(end);
3908 	}
3909 	bitmap_unplug(mddev->bitmap); /* flush the bits to disk */
3910 out:
3911 	return len;
3912 }
3913 
3914 static struct md_sysfs_entry md_bitmap =
3915 __ATTR(bitmap_set_bits, S_IWUSR, null_show, bitmap_store);
3916 
3917 static ssize_t
3918 size_show(struct mddev *mddev, char *page)
3919 {
3920 	return sprintf(page, "%llu\n",
3921 		(unsigned long long)mddev->dev_sectors / 2);
3922 }
3923 
3924 static int update_size(struct mddev *mddev, sector_t num_sectors);
3925 
3926 static ssize_t
3927 size_store(struct mddev *mddev, const char *buf, size_t len)
3928 {
3929 	/* If array is inactive, we can reduce the component size, but
3930 	 * not increase it (except from 0).
3931 	 * If array is active, we can try an on-line resize
3932 	 */
3933 	sector_t sectors;
3934 	int err = strict_blocks_to_sectors(buf, &sectors);
3935 
3936 	if (err < 0)
3937 		return err;
3938 	if (mddev->pers) {
3939 		err = update_size(mddev, sectors);
3940 		md_update_sb(mddev, 1);
3941 	} else {
3942 		if (mddev->dev_sectors == 0 ||
3943 		    mddev->dev_sectors > sectors)
3944 			mddev->dev_sectors = sectors;
3945 		else
3946 			err = -ENOSPC;
3947 	}
3948 	return err ? err : len;
3949 }
3950 
3951 static struct md_sysfs_entry md_size =
3952 __ATTR(component_size, S_IRUGO|S_IWUSR, size_show, size_store);
3953 
3954 
3955 /* Metdata version.
3956  * This is one of
3957  *   'none' for arrays with no metadata (good luck...)
3958  *   'external' for arrays with externally managed metadata,
3959  * or N.M for internally known formats
3960  */
3961 static ssize_t
3962 metadata_show(struct mddev *mddev, char *page)
3963 {
3964 	if (mddev->persistent)
3965 		return sprintf(page, "%d.%d\n",
3966 			       mddev->major_version, mddev->minor_version);
3967 	else if (mddev->external)
3968 		return sprintf(page, "external:%s\n", mddev->metadata_type);
3969 	else
3970 		return sprintf(page, "none\n");
3971 }
3972 
3973 static ssize_t
3974 metadata_store(struct mddev *mddev, const char *buf, size_t len)
3975 {
3976 	int major, minor;
3977 	char *e;
3978 	/* Changing the details of 'external' metadata is
3979 	 * always permitted.  Otherwise there must be
3980 	 * no devices attached to the array.
3981 	 */
3982 	if (mddev->external && strncmp(buf, "external:", 9) == 0)
3983 		;
3984 	else if (!list_empty(&mddev->disks))
3985 		return -EBUSY;
3986 
3987 	if (cmd_match(buf, "none")) {
3988 		mddev->persistent = 0;
3989 		mddev->external = 0;
3990 		mddev->major_version = 0;
3991 		mddev->minor_version = 90;
3992 		return len;
3993 	}
3994 	if (strncmp(buf, "external:", 9) == 0) {
3995 		size_t namelen = len-9;
3996 		if (namelen >= sizeof(mddev->metadata_type))
3997 			namelen = sizeof(mddev->metadata_type)-1;
3998 		strncpy(mddev->metadata_type, buf+9, namelen);
3999 		mddev->metadata_type[namelen] = 0;
4000 		if (namelen && mddev->metadata_type[namelen-1] == '\n')
4001 			mddev->metadata_type[--namelen] = 0;
4002 		mddev->persistent = 0;
4003 		mddev->external = 1;
4004 		mddev->major_version = 0;
4005 		mddev->minor_version = 90;
4006 		return len;
4007 	}
4008 	major = simple_strtoul(buf, &e, 10);
4009 	if (e==buf || *e != '.')
4010 		return -EINVAL;
4011 	buf = e+1;
4012 	minor = simple_strtoul(buf, &e, 10);
4013 	if (e==buf || (*e && *e != '\n') )
4014 		return -EINVAL;
4015 	if (major >= ARRAY_SIZE(super_types) || super_types[major].name == NULL)
4016 		return -ENOENT;
4017 	mddev->major_version = major;
4018 	mddev->minor_version = minor;
4019 	mddev->persistent = 1;
4020 	mddev->external = 0;
4021 	return len;
4022 }
4023 
4024 static struct md_sysfs_entry md_metadata =
4025 __ATTR(metadata_version, S_IRUGO|S_IWUSR, metadata_show, metadata_store);
4026 
4027 static ssize_t
4028 action_show(struct mddev *mddev, char *page)
4029 {
4030 	char *type = "idle";
4031 	if (test_bit(MD_RECOVERY_FROZEN, &mddev->recovery))
4032 		type = "frozen";
4033 	else if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
4034 	    (!mddev->ro && test_bit(MD_RECOVERY_NEEDED, &mddev->recovery))) {
4035 		if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
4036 			type = "reshape";
4037 		else if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
4038 			if (!test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
4039 				type = "resync";
4040 			else if (test_bit(MD_RECOVERY_CHECK, &mddev->recovery))
4041 				type = "check";
4042 			else
4043 				type = "repair";
4044 		} else if (test_bit(MD_RECOVERY_RECOVER, &mddev->recovery))
4045 			type = "recover";
4046 	}
4047 	return sprintf(page, "%s\n", type);
4048 }
4049 
4050 static void reap_sync_thread(struct mddev *mddev);
4051 
4052 static ssize_t
4053 action_store(struct mddev *mddev, const char *page, size_t len)
4054 {
4055 	if (!mddev->pers || !mddev->pers->sync_request)
4056 		return -EINVAL;
4057 
4058 	if (cmd_match(page, "frozen"))
4059 		set_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
4060 	else
4061 		clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
4062 
4063 	if (cmd_match(page, "idle") || cmd_match(page, "frozen")) {
4064 		if (mddev->sync_thread) {
4065 			set_bit(MD_RECOVERY_INTR, &mddev->recovery);
4066 			reap_sync_thread(mddev);
4067 		}
4068 	} else if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
4069 		   test_bit(MD_RECOVERY_NEEDED, &mddev->recovery))
4070 		return -EBUSY;
4071 	else if (cmd_match(page, "resync"))
4072 		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
4073 	else if (cmd_match(page, "recover")) {
4074 		set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
4075 		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
4076 	} else if (cmd_match(page, "reshape")) {
4077 		int err;
4078 		if (mddev->pers->start_reshape == NULL)
4079 			return -EINVAL;
4080 		err = mddev->pers->start_reshape(mddev);
4081 		if (err)
4082 			return err;
4083 		sysfs_notify(&mddev->kobj, NULL, "degraded");
4084 	} else {
4085 		if (cmd_match(page, "check"))
4086 			set_bit(MD_RECOVERY_CHECK, &mddev->recovery);
4087 		else if (!cmd_match(page, "repair"))
4088 			return -EINVAL;
4089 		set_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
4090 		set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
4091 	}
4092 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
4093 	md_wakeup_thread(mddev->thread);
4094 	sysfs_notify_dirent_safe(mddev->sysfs_action);
4095 	return len;
4096 }
4097 
4098 static ssize_t
4099 mismatch_cnt_show(struct mddev *mddev, char *page)
4100 {
4101 	return sprintf(page, "%llu\n",
4102 		       (unsigned long long) mddev->resync_mismatches);
4103 }
4104 
4105 static struct md_sysfs_entry md_scan_mode =
4106 __ATTR(sync_action, S_IRUGO|S_IWUSR, action_show, action_store);
4107 
4108 
4109 static struct md_sysfs_entry md_mismatches = __ATTR_RO(mismatch_cnt);
4110 
4111 static ssize_t
4112 sync_min_show(struct mddev *mddev, char *page)
4113 {
4114 	return sprintf(page, "%d (%s)\n", speed_min(mddev),
4115 		       mddev->sync_speed_min ? "local": "system");
4116 }
4117 
4118 static ssize_t
4119 sync_min_store(struct mddev *mddev, const char *buf, size_t len)
4120 {
4121 	int min;
4122 	char *e;
4123 	if (strncmp(buf, "system", 6)==0) {
4124 		mddev->sync_speed_min = 0;
4125 		return len;
4126 	}
4127 	min = simple_strtoul(buf, &e, 10);
4128 	if (buf == e || (*e && *e != '\n') || min <= 0)
4129 		return -EINVAL;
4130 	mddev->sync_speed_min = min;
4131 	return len;
4132 }
4133 
4134 static struct md_sysfs_entry md_sync_min =
4135 __ATTR(sync_speed_min, S_IRUGO|S_IWUSR, sync_min_show, sync_min_store);
4136 
4137 static ssize_t
4138 sync_max_show(struct mddev *mddev, char *page)
4139 {
4140 	return sprintf(page, "%d (%s)\n", speed_max(mddev),
4141 		       mddev->sync_speed_max ? "local": "system");
4142 }
4143 
4144 static ssize_t
4145 sync_max_store(struct mddev *mddev, const char *buf, size_t len)
4146 {
4147 	int max;
4148 	char *e;
4149 	if (strncmp(buf, "system", 6)==0) {
4150 		mddev->sync_speed_max = 0;
4151 		return len;
4152 	}
4153 	max = simple_strtoul(buf, &e, 10);
4154 	if (buf == e || (*e && *e != '\n') || max <= 0)
4155 		return -EINVAL;
4156 	mddev->sync_speed_max = max;
4157 	return len;
4158 }
4159 
4160 static struct md_sysfs_entry md_sync_max =
4161 __ATTR(sync_speed_max, S_IRUGO|S_IWUSR, sync_max_show, sync_max_store);
4162 
4163 static ssize_t
4164 degraded_show(struct mddev *mddev, char *page)
4165 {
4166 	return sprintf(page, "%d\n", mddev->degraded);
4167 }
4168 static struct md_sysfs_entry md_degraded = __ATTR_RO(degraded);
4169 
4170 static ssize_t
4171 sync_force_parallel_show(struct mddev *mddev, char *page)
4172 {
4173 	return sprintf(page, "%d\n", mddev->parallel_resync);
4174 }
4175 
4176 static ssize_t
4177 sync_force_parallel_store(struct mddev *mddev, const char *buf, size_t len)
4178 {
4179 	long n;
4180 
4181 	if (strict_strtol(buf, 10, &n))
4182 		return -EINVAL;
4183 
4184 	if (n != 0 && n != 1)
4185 		return -EINVAL;
4186 
4187 	mddev->parallel_resync = n;
4188 
4189 	if (mddev->sync_thread)
4190 		wake_up(&resync_wait);
4191 
4192 	return len;
4193 }
4194 
4195 /* force parallel resync, even with shared block devices */
4196 static struct md_sysfs_entry md_sync_force_parallel =
4197 __ATTR(sync_force_parallel, S_IRUGO|S_IWUSR,
4198        sync_force_parallel_show, sync_force_parallel_store);
4199 
4200 static ssize_t
4201 sync_speed_show(struct mddev *mddev, char *page)
4202 {
4203 	unsigned long resync, dt, db;
4204 	if (mddev->curr_resync == 0)
4205 		return sprintf(page, "none\n");
4206 	resync = mddev->curr_mark_cnt - atomic_read(&mddev->recovery_active);
4207 	dt = (jiffies - mddev->resync_mark) / HZ;
4208 	if (!dt) dt++;
4209 	db = resync - mddev->resync_mark_cnt;
4210 	return sprintf(page, "%lu\n", db/dt/2); /* K/sec */
4211 }
4212 
4213 static struct md_sysfs_entry md_sync_speed = __ATTR_RO(sync_speed);
4214 
4215 static ssize_t
4216 sync_completed_show(struct mddev *mddev, char *page)
4217 {
4218 	unsigned long long max_sectors, resync;
4219 
4220 	if (!test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
4221 		return sprintf(page, "none\n");
4222 
4223 	if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery))
4224 		max_sectors = mddev->resync_max_sectors;
4225 	else
4226 		max_sectors = mddev->dev_sectors;
4227 
4228 	resync = mddev->curr_resync_completed;
4229 	return sprintf(page, "%llu / %llu\n", resync, max_sectors);
4230 }
4231 
4232 static struct md_sysfs_entry md_sync_completed = __ATTR_RO(sync_completed);
4233 
4234 static ssize_t
4235 min_sync_show(struct mddev *mddev, char *page)
4236 {
4237 	return sprintf(page, "%llu\n",
4238 		       (unsigned long long)mddev->resync_min);
4239 }
4240 static ssize_t
4241 min_sync_store(struct mddev *mddev, const char *buf, size_t len)
4242 {
4243 	unsigned long long min;
4244 	if (strict_strtoull(buf, 10, &min))
4245 		return -EINVAL;
4246 	if (min > mddev->resync_max)
4247 		return -EINVAL;
4248 	if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
4249 		return -EBUSY;
4250 
4251 	/* Must be a multiple of chunk_size */
4252 	if (mddev->chunk_sectors) {
4253 		sector_t temp = min;
4254 		if (sector_div(temp, mddev->chunk_sectors))
4255 			return -EINVAL;
4256 	}
4257 	mddev->resync_min = min;
4258 
4259 	return len;
4260 }
4261 
4262 static struct md_sysfs_entry md_min_sync =
4263 __ATTR(sync_min, S_IRUGO|S_IWUSR, min_sync_show, min_sync_store);
4264 
4265 static ssize_t
4266 max_sync_show(struct mddev *mddev, char *page)
4267 {
4268 	if (mddev->resync_max == MaxSector)
4269 		return sprintf(page, "max\n");
4270 	else
4271 		return sprintf(page, "%llu\n",
4272 			       (unsigned long long)mddev->resync_max);
4273 }
4274 static ssize_t
4275 max_sync_store(struct mddev *mddev, const char *buf, size_t len)
4276 {
4277 	if (strncmp(buf, "max", 3) == 0)
4278 		mddev->resync_max = MaxSector;
4279 	else {
4280 		unsigned long long max;
4281 		if (strict_strtoull(buf, 10, &max))
4282 			return -EINVAL;
4283 		if (max < mddev->resync_min)
4284 			return -EINVAL;
4285 		if (max < mddev->resync_max &&
4286 		    mddev->ro == 0 &&
4287 		    test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
4288 			return -EBUSY;
4289 
4290 		/* Must be a multiple of chunk_size */
4291 		if (mddev->chunk_sectors) {
4292 			sector_t temp = max;
4293 			if (sector_div(temp, mddev->chunk_sectors))
4294 				return -EINVAL;
4295 		}
4296 		mddev->resync_max = max;
4297 	}
4298 	wake_up(&mddev->recovery_wait);
4299 	return len;
4300 }
4301 
4302 static struct md_sysfs_entry md_max_sync =
4303 __ATTR(sync_max, S_IRUGO|S_IWUSR, max_sync_show, max_sync_store);
4304 
4305 static ssize_t
4306 suspend_lo_show(struct mddev *mddev, char *page)
4307 {
4308 	return sprintf(page, "%llu\n", (unsigned long long)mddev->suspend_lo);
4309 }
4310 
4311 static ssize_t
4312 suspend_lo_store(struct mddev *mddev, const char *buf, size_t len)
4313 {
4314 	char *e;
4315 	unsigned long long new = simple_strtoull(buf, &e, 10);
4316 	unsigned long long old = mddev->suspend_lo;
4317 
4318 	if (mddev->pers == NULL ||
4319 	    mddev->pers->quiesce == NULL)
4320 		return -EINVAL;
4321 	if (buf == e || (*e && *e != '\n'))
4322 		return -EINVAL;
4323 
4324 	mddev->suspend_lo = new;
4325 	if (new >= old)
4326 		/* Shrinking suspended region */
4327 		mddev->pers->quiesce(mddev, 2);
4328 	else {
4329 		/* Expanding suspended region - need to wait */
4330 		mddev->pers->quiesce(mddev, 1);
4331 		mddev->pers->quiesce(mddev, 0);
4332 	}
4333 	return len;
4334 }
4335 static struct md_sysfs_entry md_suspend_lo =
4336 __ATTR(suspend_lo, S_IRUGO|S_IWUSR, suspend_lo_show, suspend_lo_store);
4337 
4338 
4339 static ssize_t
4340 suspend_hi_show(struct mddev *mddev, char *page)
4341 {
4342 	return sprintf(page, "%llu\n", (unsigned long long)mddev->suspend_hi);
4343 }
4344 
4345 static ssize_t
4346 suspend_hi_store(struct mddev *mddev, const char *buf, size_t len)
4347 {
4348 	char *e;
4349 	unsigned long long new = simple_strtoull(buf, &e, 10);
4350 	unsigned long long old = mddev->suspend_hi;
4351 
4352 	if (mddev->pers == NULL ||
4353 	    mddev->pers->quiesce == NULL)
4354 		return -EINVAL;
4355 	if (buf == e || (*e && *e != '\n'))
4356 		return -EINVAL;
4357 
4358 	mddev->suspend_hi = new;
4359 	if (new <= old)
4360 		/* Shrinking suspended region */
4361 		mddev->pers->quiesce(mddev, 2);
4362 	else {
4363 		/* Expanding suspended region - need to wait */
4364 		mddev->pers->quiesce(mddev, 1);
4365 		mddev->pers->quiesce(mddev, 0);
4366 	}
4367 	return len;
4368 }
4369 static struct md_sysfs_entry md_suspend_hi =
4370 __ATTR(suspend_hi, S_IRUGO|S_IWUSR, suspend_hi_show, suspend_hi_store);
4371 
4372 static ssize_t
4373 reshape_position_show(struct mddev *mddev, char *page)
4374 {
4375 	if (mddev->reshape_position != MaxSector)
4376 		return sprintf(page, "%llu\n",
4377 			       (unsigned long long)mddev->reshape_position);
4378 	strcpy(page, "none\n");
4379 	return 5;
4380 }
4381 
4382 static ssize_t
4383 reshape_position_store(struct mddev *mddev, const char *buf, size_t len)
4384 {
4385 	char *e;
4386 	unsigned long long new = simple_strtoull(buf, &e, 10);
4387 	if (mddev->pers)
4388 		return -EBUSY;
4389 	if (buf == e || (*e && *e != '\n'))
4390 		return -EINVAL;
4391 	mddev->reshape_position = new;
4392 	mddev->delta_disks = 0;
4393 	mddev->new_level = mddev->level;
4394 	mddev->new_layout = mddev->layout;
4395 	mddev->new_chunk_sectors = mddev->chunk_sectors;
4396 	return len;
4397 }
4398 
4399 static struct md_sysfs_entry md_reshape_position =
4400 __ATTR(reshape_position, S_IRUGO|S_IWUSR, reshape_position_show,
4401        reshape_position_store);
4402 
4403 static ssize_t
4404 array_size_show(struct mddev *mddev, char *page)
4405 {
4406 	if (mddev->external_size)
4407 		return sprintf(page, "%llu\n",
4408 			       (unsigned long long)mddev->array_sectors/2);
4409 	else
4410 		return sprintf(page, "default\n");
4411 }
4412 
4413 static ssize_t
4414 array_size_store(struct mddev *mddev, const char *buf, size_t len)
4415 {
4416 	sector_t sectors;
4417 
4418 	if (strncmp(buf, "default", 7) == 0) {
4419 		if (mddev->pers)
4420 			sectors = mddev->pers->size(mddev, 0, 0);
4421 		else
4422 			sectors = mddev->array_sectors;
4423 
4424 		mddev->external_size = 0;
4425 	} else {
4426 		if (strict_blocks_to_sectors(buf, &sectors) < 0)
4427 			return -EINVAL;
4428 		if (mddev->pers && mddev->pers->size(mddev, 0, 0) < sectors)
4429 			return -E2BIG;
4430 
4431 		mddev->external_size = 1;
4432 	}
4433 
4434 	mddev->array_sectors = sectors;
4435 	if (mddev->pers) {
4436 		set_capacity(mddev->gendisk, mddev->array_sectors);
4437 		revalidate_disk(mddev->gendisk);
4438 	}
4439 	return len;
4440 }
4441 
4442 static struct md_sysfs_entry md_array_size =
4443 __ATTR(array_size, S_IRUGO|S_IWUSR, array_size_show,
4444        array_size_store);
4445 
4446 static struct attribute *md_default_attrs[] = {
4447 	&md_level.attr,
4448 	&md_layout.attr,
4449 	&md_raid_disks.attr,
4450 	&md_chunk_size.attr,
4451 	&md_size.attr,
4452 	&md_resync_start.attr,
4453 	&md_metadata.attr,
4454 	&md_new_device.attr,
4455 	&md_safe_delay.attr,
4456 	&md_array_state.attr,
4457 	&md_reshape_position.attr,
4458 	&md_array_size.attr,
4459 	&max_corr_read_errors.attr,
4460 	NULL,
4461 };
4462 
4463 static struct attribute *md_redundancy_attrs[] = {
4464 	&md_scan_mode.attr,
4465 	&md_mismatches.attr,
4466 	&md_sync_min.attr,
4467 	&md_sync_max.attr,
4468 	&md_sync_speed.attr,
4469 	&md_sync_force_parallel.attr,
4470 	&md_sync_completed.attr,
4471 	&md_min_sync.attr,
4472 	&md_max_sync.attr,
4473 	&md_suspend_lo.attr,
4474 	&md_suspend_hi.attr,
4475 	&md_bitmap.attr,
4476 	&md_degraded.attr,
4477 	NULL,
4478 };
4479 static struct attribute_group md_redundancy_group = {
4480 	.name = NULL,
4481 	.attrs = md_redundancy_attrs,
4482 };
4483 
4484 
4485 static ssize_t
4486 md_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
4487 {
4488 	struct md_sysfs_entry *entry = container_of(attr, struct md_sysfs_entry, attr);
4489 	struct mddev *mddev = container_of(kobj, struct mddev, kobj);
4490 	ssize_t rv;
4491 
4492 	if (!entry->show)
4493 		return -EIO;
4494 	rv = mddev_lock(mddev);
4495 	if (!rv) {
4496 		rv = entry->show(mddev, page);
4497 		mddev_unlock(mddev);
4498 	}
4499 	return rv;
4500 }
4501 
4502 static ssize_t
4503 md_attr_store(struct kobject *kobj, struct attribute *attr,
4504 	      const char *page, size_t length)
4505 {
4506 	struct md_sysfs_entry *entry = container_of(attr, struct md_sysfs_entry, attr);
4507 	struct mddev *mddev = container_of(kobj, struct mddev, kobj);
4508 	ssize_t rv;
4509 
4510 	if (!entry->store)
4511 		return -EIO;
4512 	if (!capable(CAP_SYS_ADMIN))
4513 		return -EACCES;
4514 	rv = mddev_lock(mddev);
4515 	if (mddev->hold_active == UNTIL_IOCTL)
4516 		mddev->hold_active = 0;
4517 	if (!rv) {
4518 		rv = entry->store(mddev, page, length);
4519 		mddev_unlock(mddev);
4520 	}
4521 	return rv;
4522 }
4523 
4524 static void md_free(struct kobject *ko)
4525 {
4526 	struct mddev *mddev = container_of(ko, struct mddev, kobj);
4527 
4528 	if (mddev->sysfs_state)
4529 		sysfs_put(mddev->sysfs_state);
4530 
4531 	if (mddev->gendisk) {
4532 		del_gendisk(mddev->gendisk);
4533 		put_disk(mddev->gendisk);
4534 	}
4535 	if (mddev->queue)
4536 		blk_cleanup_queue(mddev->queue);
4537 
4538 	kfree(mddev);
4539 }
4540 
4541 static const struct sysfs_ops md_sysfs_ops = {
4542 	.show	= md_attr_show,
4543 	.store	= md_attr_store,
4544 };
4545 static struct kobj_type md_ktype = {
4546 	.release	= md_free,
4547 	.sysfs_ops	= &md_sysfs_ops,
4548 	.default_attrs	= md_default_attrs,
4549 };
4550 
4551 int mdp_major = 0;
4552 
4553 static void mddev_delayed_delete(struct work_struct *ws)
4554 {
4555 	struct mddev *mddev = container_of(ws, struct mddev, del_work);
4556 
4557 	sysfs_remove_group(&mddev->kobj, &md_bitmap_group);
4558 	kobject_del(&mddev->kobj);
4559 	kobject_put(&mddev->kobj);
4560 }
4561 
4562 static int md_alloc(dev_t dev, char *name)
4563 {
4564 	static DEFINE_MUTEX(disks_mutex);
4565 	struct mddev *mddev = mddev_find(dev);
4566 	struct gendisk *disk;
4567 	int partitioned;
4568 	int shift;
4569 	int unit;
4570 	int error;
4571 
4572 	if (!mddev)
4573 		return -ENODEV;
4574 
4575 	partitioned = (MAJOR(mddev->unit) != MD_MAJOR);
4576 	shift = partitioned ? MdpMinorShift : 0;
4577 	unit = MINOR(mddev->unit) >> shift;
4578 
4579 	/* wait for any previous instance of this device to be
4580 	 * completely removed (mddev_delayed_delete).
4581 	 */
4582 	flush_workqueue(md_misc_wq);
4583 
4584 	mutex_lock(&disks_mutex);
4585 	error = -EEXIST;
4586 	if (mddev->gendisk)
4587 		goto abort;
4588 
4589 	if (name) {
4590 		/* Need to ensure that 'name' is not a duplicate.
4591 		 */
4592 		struct mddev *mddev2;
4593 		spin_lock(&all_mddevs_lock);
4594 
4595 		list_for_each_entry(mddev2, &all_mddevs, all_mddevs)
4596 			if (mddev2->gendisk &&
4597 			    strcmp(mddev2->gendisk->disk_name, name) == 0) {
4598 				spin_unlock(&all_mddevs_lock);
4599 				goto abort;
4600 			}
4601 		spin_unlock(&all_mddevs_lock);
4602 	}
4603 
4604 	error = -ENOMEM;
4605 	mddev->queue = blk_alloc_queue(GFP_KERNEL);
4606 	if (!mddev->queue)
4607 		goto abort;
4608 	mddev->queue->queuedata = mddev;
4609 
4610 	blk_queue_make_request(mddev->queue, md_make_request);
4611 
4612 	disk = alloc_disk(1 << shift);
4613 	if (!disk) {
4614 		blk_cleanup_queue(mddev->queue);
4615 		mddev->queue = NULL;
4616 		goto abort;
4617 	}
4618 	disk->major = MAJOR(mddev->unit);
4619 	disk->first_minor = unit << shift;
4620 	if (name)
4621 		strcpy(disk->disk_name, name);
4622 	else if (partitioned)
4623 		sprintf(disk->disk_name, "md_d%d", unit);
4624 	else
4625 		sprintf(disk->disk_name, "md%d", unit);
4626 	disk->fops = &md_fops;
4627 	disk->private_data = mddev;
4628 	disk->queue = mddev->queue;
4629 	blk_queue_flush(mddev->queue, REQ_FLUSH | REQ_FUA);
4630 	/* Allow extended partitions.  This makes the
4631 	 * 'mdp' device redundant, but we can't really
4632 	 * remove it now.
4633 	 */
4634 	disk->flags |= GENHD_FL_EXT_DEVT;
4635 	mddev->gendisk = disk;
4636 	/* As soon as we call add_disk(), another thread could get
4637 	 * through to md_open, so make sure it doesn't get too far
4638 	 */
4639 	mutex_lock(&mddev->open_mutex);
4640 	add_disk(disk);
4641 
4642 	error = kobject_init_and_add(&mddev->kobj, &md_ktype,
4643 				     &disk_to_dev(disk)->kobj, "%s", "md");
4644 	if (error) {
4645 		/* This isn't possible, but as kobject_init_and_add is marked
4646 		 * __must_check, we must do something with the result
4647 		 */
4648 		printk(KERN_WARNING "md: cannot register %s/md - name in use\n",
4649 		       disk->disk_name);
4650 		error = 0;
4651 	}
4652 	if (mddev->kobj.sd &&
4653 	    sysfs_create_group(&mddev->kobj, &md_bitmap_group))
4654 		printk(KERN_DEBUG "pointless warning\n");
4655 	mutex_unlock(&mddev->open_mutex);
4656  abort:
4657 	mutex_unlock(&disks_mutex);
4658 	if (!error && mddev->kobj.sd) {
4659 		kobject_uevent(&mddev->kobj, KOBJ_ADD);
4660 		mddev->sysfs_state = sysfs_get_dirent_safe(mddev->kobj.sd, "array_state");
4661 	}
4662 	mddev_put(mddev);
4663 	return error;
4664 }
4665 
4666 static struct kobject *md_probe(dev_t dev, int *part, void *data)
4667 {
4668 	md_alloc(dev, NULL);
4669 	return NULL;
4670 }
4671 
4672 static int add_named_array(const char *val, struct kernel_param *kp)
4673 {
4674 	/* val must be "md_*" where * is not all digits.
4675 	 * We allocate an array with a large free minor number, and
4676 	 * set the name to val.  val must not already be an active name.
4677 	 */
4678 	int len = strlen(val);
4679 	char buf[DISK_NAME_LEN];
4680 
4681 	while (len && val[len-1] == '\n')
4682 		len--;
4683 	if (len >= DISK_NAME_LEN)
4684 		return -E2BIG;
4685 	strlcpy(buf, val, len+1);
4686 	if (strncmp(buf, "md_", 3) != 0)
4687 		return -EINVAL;
4688 	return md_alloc(0, buf);
4689 }
4690 
4691 static void md_safemode_timeout(unsigned long data)
4692 {
4693 	struct mddev *mddev = (struct mddev *) data;
4694 
4695 	if (!atomic_read(&mddev->writes_pending)) {
4696 		mddev->safemode = 1;
4697 		if (mddev->external)
4698 			sysfs_notify_dirent_safe(mddev->sysfs_state);
4699 	}
4700 	md_wakeup_thread(mddev->thread);
4701 }
4702 
4703 static int start_dirty_degraded;
4704 
4705 int md_run(struct mddev *mddev)
4706 {
4707 	int err;
4708 	struct md_rdev *rdev;
4709 	struct md_personality *pers;
4710 
4711 	if (list_empty(&mddev->disks))
4712 		/* cannot run an array with no devices.. */
4713 		return -EINVAL;
4714 
4715 	if (mddev->pers)
4716 		return -EBUSY;
4717 	/* Cannot run until previous stop completes properly */
4718 	if (mddev->sysfs_active)
4719 		return -EBUSY;
4720 
4721 	/*
4722 	 * Analyze all RAID superblock(s)
4723 	 */
4724 	if (!mddev->raid_disks) {
4725 		if (!mddev->persistent)
4726 			return -EINVAL;
4727 		analyze_sbs(mddev);
4728 	}
4729 
4730 	if (mddev->level != LEVEL_NONE)
4731 		request_module("md-level-%d", mddev->level);
4732 	else if (mddev->clevel[0])
4733 		request_module("md-%s", mddev->clevel);
4734 
4735 	/*
4736 	 * Drop all container device buffers, from now on
4737 	 * the only valid external interface is through the md
4738 	 * device.
4739 	 */
4740 	list_for_each_entry(rdev, &mddev->disks, same_set) {
4741 		if (test_bit(Faulty, &rdev->flags))
4742 			continue;
4743 		sync_blockdev(rdev->bdev);
4744 		invalidate_bdev(rdev->bdev);
4745 
4746 		/* perform some consistency tests on the device.
4747 		 * We don't want the data to overlap the metadata,
4748 		 * Internal Bitmap issues have been handled elsewhere.
4749 		 */
4750 		if (rdev->meta_bdev) {
4751 			/* Nothing to check */;
4752 		} else if (rdev->data_offset < rdev->sb_start) {
4753 			if (mddev->dev_sectors &&
4754 			    rdev->data_offset + mddev->dev_sectors
4755 			    > rdev->sb_start) {
4756 				printk("md: %s: data overlaps metadata\n",
4757 				       mdname(mddev));
4758 				return -EINVAL;
4759 			}
4760 		} else {
4761 			if (rdev->sb_start + rdev->sb_size/512
4762 			    > rdev->data_offset) {
4763 				printk("md: %s: metadata overlaps data\n",
4764 				       mdname(mddev));
4765 				return -EINVAL;
4766 			}
4767 		}
4768 		sysfs_notify_dirent_safe(rdev->sysfs_state);
4769 	}
4770 
4771 	if (mddev->bio_set == NULL)
4772 		mddev->bio_set = bioset_create(BIO_POOL_SIZE,
4773 					       sizeof(struct mddev *));
4774 
4775 	spin_lock(&pers_lock);
4776 	pers = find_pers(mddev->level, mddev->clevel);
4777 	if (!pers || !try_module_get(pers->owner)) {
4778 		spin_unlock(&pers_lock);
4779 		if (mddev->level != LEVEL_NONE)
4780 			printk(KERN_WARNING "md: personality for level %d is not loaded!\n",
4781 			       mddev->level);
4782 		else
4783 			printk(KERN_WARNING "md: personality for level %s is not loaded!\n",
4784 			       mddev->clevel);
4785 		return -EINVAL;
4786 	}
4787 	mddev->pers = pers;
4788 	spin_unlock(&pers_lock);
4789 	if (mddev->level != pers->level) {
4790 		mddev->level = pers->level;
4791 		mddev->new_level = pers->level;
4792 	}
4793 	strlcpy(mddev->clevel, pers->name, sizeof(mddev->clevel));
4794 
4795 	if (mddev->reshape_position != MaxSector &&
4796 	    pers->start_reshape == NULL) {
4797 		/* This personality cannot handle reshaping... */
4798 		mddev->pers = NULL;
4799 		module_put(pers->owner);
4800 		return -EINVAL;
4801 	}
4802 
4803 	if (pers->sync_request) {
4804 		/* Warn if this is a potentially silly
4805 		 * configuration.
4806 		 */
4807 		char b[BDEVNAME_SIZE], b2[BDEVNAME_SIZE];
4808 		struct md_rdev *rdev2;
4809 		int warned = 0;
4810 
4811 		list_for_each_entry(rdev, &mddev->disks, same_set)
4812 			list_for_each_entry(rdev2, &mddev->disks, same_set) {
4813 				if (rdev < rdev2 &&
4814 				    rdev->bdev->bd_contains ==
4815 				    rdev2->bdev->bd_contains) {
4816 					printk(KERN_WARNING
4817 					       "%s: WARNING: %s appears to be"
4818 					       " on the same physical disk as"
4819 					       " %s.\n",
4820 					       mdname(mddev),
4821 					       bdevname(rdev->bdev,b),
4822 					       bdevname(rdev2->bdev,b2));
4823 					warned = 1;
4824 				}
4825 			}
4826 
4827 		if (warned)
4828 			printk(KERN_WARNING
4829 			       "True protection against single-disk"
4830 			       " failure might be compromised.\n");
4831 	}
4832 
4833 	mddev->recovery = 0;
4834 	/* may be over-ridden by personality */
4835 	mddev->resync_max_sectors = mddev->dev_sectors;
4836 
4837 	mddev->ok_start_degraded = start_dirty_degraded;
4838 
4839 	if (start_readonly && mddev->ro == 0)
4840 		mddev->ro = 2; /* read-only, but switch on first write */
4841 
4842 	err = mddev->pers->run(mddev);
4843 	if (err)
4844 		printk(KERN_ERR "md: pers->run() failed ...\n");
4845 	else if (mddev->pers->size(mddev, 0, 0) < mddev->array_sectors) {
4846 		WARN_ONCE(!mddev->external_size, "%s: default size too small,"
4847 			  " but 'external_size' not in effect?\n", __func__);
4848 		printk(KERN_ERR
4849 		       "md: invalid array_size %llu > default size %llu\n",
4850 		       (unsigned long long)mddev->array_sectors / 2,
4851 		       (unsigned long long)mddev->pers->size(mddev, 0, 0) / 2);
4852 		err = -EINVAL;
4853 		mddev->pers->stop(mddev);
4854 	}
4855 	if (err == 0 && mddev->pers->sync_request) {
4856 		err = bitmap_create(mddev);
4857 		if (err) {
4858 			printk(KERN_ERR "%s: failed to create bitmap (%d)\n",
4859 			       mdname(mddev), err);
4860 			mddev->pers->stop(mddev);
4861 		}
4862 	}
4863 	if (err) {
4864 		module_put(mddev->pers->owner);
4865 		mddev->pers = NULL;
4866 		bitmap_destroy(mddev);
4867 		return err;
4868 	}
4869 	if (mddev->pers->sync_request) {
4870 		if (mddev->kobj.sd &&
4871 		    sysfs_create_group(&mddev->kobj, &md_redundancy_group))
4872 			printk(KERN_WARNING
4873 			       "md: cannot register extra attributes for %s\n",
4874 			       mdname(mddev));
4875 		mddev->sysfs_action = sysfs_get_dirent_safe(mddev->kobj.sd, "sync_action");
4876 	} else if (mddev->ro == 2) /* auto-readonly not meaningful */
4877 		mddev->ro = 0;
4878 
4879  	atomic_set(&mddev->writes_pending,0);
4880 	atomic_set(&mddev->max_corr_read_errors,
4881 		   MD_DEFAULT_MAX_CORRECTED_READ_ERRORS);
4882 	mddev->safemode = 0;
4883 	mddev->safemode_timer.function = md_safemode_timeout;
4884 	mddev->safemode_timer.data = (unsigned long) mddev;
4885 	mddev->safemode_delay = (200 * HZ)/1000 +1; /* 200 msec delay */
4886 	mddev->in_sync = 1;
4887 	smp_wmb();
4888 	mddev->ready = 1;
4889 	list_for_each_entry(rdev, &mddev->disks, same_set)
4890 		if (rdev->raid_disk >= 0)
4891 			if (sysfs_link_rdev(mddev, rdev))
4892 				/* failure here is OK */;
4893 
4894 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
4895 
4896 	if (mddev->flags)
4897 		md_update_sb(mddev, 0);
4898 
4899 	md_new_event(mddev);
4900 	sysfs_notify_dirent_safe(mddev->sysfs_state);
4901 	sysfs_notify_dirent_safe(mddev->sysfs_action);
4902 	sysfs_notify(&mddev->kobj, NULL, "degraded");
4903 	return 0;
4904 }
4905 EXPORT_SYMBOL_GPL(md_run);
4906 
4907 static int do_md_run(struct mddev *mddev)
4908 {
4909 	int err;
4910 
4911 	err = md_run(mddev);
4912 	if (err)
4913 		goto out;
4914 	err = bitmap_load(mddev);
4915 	if (err) {
4916 		bitmap_destroy(mddev);
4917 		goto out;
4918 	}
4919 
4920 	md_wakeup_thread(mddev->thread);
4921 	md_wakeup_thread(mddev->sync_thread); /* possibly kick off a reshape */
4922 
4923 	set_capacity(mddev->gendisk, mddev->array_sectors);
4924 	revalidate_disk(mddev->gendisk);
4925 	mddev->changed = 1;
4926 	kobject_uevent(&disk_to_dev(mddev->gendisk)->kobj, KOBJ_CHANGE);
4927 out:
4928 	return err;
4929 }
4930 
4931 static int restart_array(struct mddev *mddev)
4932 {
4933 	struct gendisk *disk = mddev->gendisk;
4934 
4935 	/* Complain if it has no devices */
4936 	if (list_empty(&mddev->disks))
4937 		return -ENXIO;
4938 	if (!mddev->pers)
4939 		return -EINVAL;
4940 	if (!mddev->ro)
4941 		return -EBUSY;
4942 	mddev->safemode = 0;
4943 	mddev->ro = 0;
4944 	set_disk_ro(disk, 0);
4945 	printk(KERN_INFO "md: %s switched to read-write mode.\n",
4946 		mdname(mddev));
4947 	/* Kick recovery or resync if necessary */
4948 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
4949 	md_wakeup_thread(mddev->thread);
4950 	md_wakeup_thread(mddev->sync_thread);
4951 	sysfs_notify_dirent_safe(mddev->sysfs_state);
4952 	return 0;
4953 }
4954 
4955 /* similar to deny_write_access, but accounts for our holding a reference
4956  * to the file ourselves */
4957 static int deny_bitmap_write_access(struct file * file)
4958 {
4959 	struct inode *inode = file->f_mapping->host;
4960 
4961 	spin_lock(&inode->i_lock);
4962 	if (atomic_read(&inode->i_writecount) > 1) {
4963 		spin_unlock(&inode->i_lock);
4964 		return -ETXTBSY;
4965 	}
4966 	atomic_set(&inode->i_writecount, -1);
4967 	spin_unlock(&inode->i_lock);
4968 
4969 	return 0;
4970 }
4971 
4972 void restore_bitmap_write_access(struct file *file)
4973 {
4974 	struct inode *inode = file->f_mapping->host;
4975 
4976 	spin_lock(&inode->i_lock);
4977 	atomic_set(&inode->i_writecount, 1);
4978 	spin_unlock(&inode->i_lock);
4979 }
4980 
4981 static void md_clean(struct mddev *mddev)
4982 {
4983 	mddev->array_sectors = 0;
4984 	mddev->external_size = 0;
4985 	mddev->dev_sectors = 0;
4986 	mddev->raid_disks = 0;
4987 	mddev->recovery_cp = 0;
4988 	mddev->resync_min = 0;
4989 	mddev->resync_max = MaxSector;
4990 	mddev->reshape_position = MaxSector;
4991 	mddev->external = 0;
4992 	mddev->persistent = 0;
4993 	mddev->level = LEVEL_NONE;
4994 	mddev->clevel[0] = 0;
4995 	mddev->flags = 0;
4996 	mddev->ro = 0;
4997 	mddev->metadata_type[0] = 0;
4998 	mddev->chunk_sectors = 0;
4999 	mddev->ctime = mddev->utime = 0;
5000 	mddev->layout = 0;
5001 	mddev->max_disks = 0;
5002 	mddev->events = 0;
5003 	mddev->can_decrease_events = 0;
5004 	mddev->delta_disks = 0;
5005 	mddev->new_level = LEVEL_NONE;
5006 	mddev->new_layout = 0;
5007 	mddev->new_chunk_sectors = 0;
5008 	mddev->curr_resync = 0;
5009 	mddev->resync_mismatches = 0;
5010 	mddev->suspend_lo = mddev->suspend_hi = 0;
5011 	mddev->sync_speed_min = mddev->sync_speed_max = 0;
5012 	mddev->recovery = 0;
5013 	mddev->in_sync = 0;
5014 	mddev->changed = 0;
5015 	mddev->degraded = 0;
5016 	mddev->safemode = 0;
5017 	mddev->bitmap_info.offset = 0;
5018 	mddev->bitmap_info.default_offset = 0;
5019 	mddev->bitmap_info.chunksize = 0;
5020 	mddev->bitmap_info.daemon_sleep = 0;
5021 	mddev->bitmap_info.max_write_behind = 0;
5022 }
5023 
5024 static void __md_stop_writes(struct mddev *mddev)
5025 {
5026 	if (mddev->sync_thread) {
5027 		set_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
5028 		set_bit(MD_RECOVERY_INTR, &mddev->recovery);
5029 		reap_sync_thread(mddev);
5030 	}
5031 
5032 	del_timer_sync(&mddev->safemode_timer);
5033 
5034 	bitmap_flush(mddev);
5035 	md_super_wait(mddev);
5036 
5037 	if (!mddev->in_sync || mddev->flags) {
5038 		/* mark array as shutdown cleanly */
5039 		mddev->in_sync = 1;
5040 		md_update_sb(mddev, 1);
5041 	}
5042 }
5043 
5044 void md_stop_writes(struct mddev *mddev)
5045 {
5046 	mddev_lock(mddev);
5047 	__md_stop_writes(mddev);
5048 	mddev_unlock(mddev);
5049 }
5050 EXPORT_SYMBOL_GPL(md_stop_writes);
5051 
5052 void md_stop(struct mddev *mddev)
5053 {
5054 	mddev->ready = 0;
5055 	mddev->pers->stop(mddev);
5056 	if (mddev->pers->sync_request && mddev->to_remove == NULL)
5057 		mddev->to_remove = &md_redundancy_group;
5058 	module_put(mddev->pers->owner);
5059 	mddev->pers = NULL;
5060 	clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
5061 }
5062 EXPORT_SYMBOL_GPL(md_stop);
5063 
5064 static int md_set_readonly(struct mddev *mddev, int is_open)
5065 {
5066 	int err = 0;
5067 	mutex_lock(&mddev->open_mutex);
5068 	if (atomic_read(&mddev->openers) > is_open) {
5069 		printk("md: %s still in use.\n",mdname(mddev));
5070 		err = -EBUSY;
5071 		goto out;
5072 	}
5073 	if (mddev->pers) {
5074 		__md_stop_writes(mddev);
5075 
5076 		err  = -ENXIO;
5077 		if (mddev->ro==1)
5078 			goto out;
5079 		mddev->ro = 1;
5080 		set_disk_ro(mddev->gendisk, 1);
5081 		clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
5082 		sysfs_notify_dirent_safe(mddev->sysfs_state);
5083 		err = 0;
5084 	}
5085 out:
5086 	mutex_unlock(&mddev->open_mutex);
5087 	return err;
5088 }
5089 
5090 /* mode:
5091  *   0 - completely stop and dis-assemble array
5092  *   2 - stop but do not disassemble array
5093  */
5094 static int do_md_stop(struct mddev * mddev, int mode, int is_open)
5095 {
5096 	struct gendisk *disk = mddev->gendisk;
5097 	struct md_rdev *rdev;
5098 
5099 	mutex_lock(&mddev->open_mutex);
5100 	if (atomic_read(&mddev->openers) > is_open ||
5101 	    mddev->sysfs_active) {
5102 		printk("md: %s still in use.\n",mdname(mddev));
5103 		mutex_unlock(&mddev->open_mutex);
5104 		return -EBUSY;
5105 	}
5106 
5107 	if (mddev->pers) {
5108 		if (mddev->ro)
5109 			set_disk_ro(disk, 0);
5110 
5111 		__md_stop_writes(mddev);
5112 		md_stop(mddev);
5113 		mddev->queue->merge_bvec_fn = NULL;
5114 		mddev->queue->backing_dev_info.congested_fn = NULL;
5115 
5116 		/* tell userspace to handle 'inactive' */
5117 		sysfs_notify_dirent_safe(mddev->sysfs_state);
5118 
5119 		list_for_each_entry(rdev, &mddev->disks, same_set)
5120 			if (rdev->raid_disk >= 0)
5121 				sysfs_unlink_rdev(mddev, rdev);
5122 
5123 		set_capacity(disk, 0);
5124 		mutex_unlock(&mddev->open_mutex);
5125 		mddev->changed = 1;
5126 		revalidate_disk(disk);
5127 
5128 		if (mddev->ro)
5129 			mddev->ro = 0;
5130 	} else
5131 		mutex_unlock(&mddev->open_mutex);
5132 	/*
5133 	 * Free resources if final stop
5134 	 */
5135 	if (mode == 0) {
5136 		printk(KERN_INFO "md: %s stopped.\n", mdname(mddev));
5137 
5138 		bitmap_destroy(mddev);
5139 		if (mddev->bitmap_info.file) {
5140 			restore_bitmap_write_access(mddev->bitmap_info.file);
5141 			fput(mddev->bitmap_info.file);
5142 			mddev->bitmap_info.file = NULL;
5143 		}
5144 		mddev->bitmap_info.offset = 0;
5145 
5146 		export_array(mddev);
5147 
5148 		md_clean(mddev);
5149 		kobject_uevent(&disk_to_dev(mddev->gendisk)->kobj, KOBJ_CHANGE);
5150 		if (mddev->hold_active == UNTIL_STOP)
5151 			mddev->hold_active = 0;
5152 	}
5153 	blk_integrity_unregister(disk);
5154 	md_new_event(mddev);
5155 	sysfs_notify_dirent_safe(mddev->sysfs_state);
5156 	return 0;
5157 }
5158 
5159 #ifndef MODULE
5160 static void autorun_array(struct mddev *mddev)
5161 {
5162 	struct md_rdev *rdev;
5163 	int err;
5164 
5165 	if (list_empty(&mddev->disks))
5166 		return;
5167 
5168 	printk(KERN_INFO "md: running: ");
5169 
5170 	list_for_each_entry(rdev, &mddev->disks, same_set) {
5171 		char b[BDEVNAME_SIZE];
5172 		printk("<%s>", bdevname(rdev->bdev,b));
5173 	}
5174 	printk("\n");
5175 
5176 	err = do_md_run(mddev);
5177 	if (err) {
5178 		printk(KERN_WARNING "md: do_md_run() returned %d\n", err);
5179 		do_md_stop(mddev, 0, 0);
5180 	}
5181 }
5182 
5183 /*
5184  * lets try to run arrays based on all disks that have arrived
5185  * until now. (those are in pending_raid_disks)
5186  *
5187  * the method: pick the first pending disk, collect all disks with
5188  * the same UUID, remove all from the pending list and put them into
5189  * the 'same_array' list. Then order this list based on superblock
5190  * update time (freshest comes first), kick out 'old' disks and
5191  * compare superblocks. If everything's fine then run it.
5192  *
5193  * If "unit" is allocated, then bump its reference count
5194  */
5195 static void autorun_devices(int part)
5196 {
5197 	struct md_rdev *rdev0, *rdev, *tmp;
5198 	struct mddev *mddev;
5199 	char b[BDEVNAME_SIZE];
5200 
5201 	printk(KERN_INFO "md: autorun ...\n");
5202 	while (!list_empty(&pending_raid_disks)) {
5203 		int unit;
5204 		dev_t dev;
5205 		LIST_HEAD(candidates);
5206 		rdev0 = list_entry(pending_raid_disks.next,
5207 					 struct md_rdev, same_set);
5208 
5209 		printk(KERN_INFO "md: considering %s ...\n",
5210 			bdevname(rdev0->bdev,b));
5211 		INIT_LIST_HEAD(&candidates);
5212 		rdev_for_each_list(rdev, tmp, &pending_raid_disks)
5213 			if (super_90_load(rdev, rdev0, 0) >= 0) {
5214 				printk(KERN_INFO "md:  adding %s ...\n",
5215 					bdevname(rdev->bdev,b));
5216 				list_move(&rdev->same_set, &candidates);
5217 			}
5218 		/*
5219 		 * now we have a set of devices, with all of them having
5220 		 * mostly sane superblocks. It's time to allocate the
5221 		 * mddev.
5222 		 */
5223 		if (part) {
5224 			dev = MKDEV(mdp_major,
5225 				    rdev0->preferred_minor << MdpMinorShift);
5226 			unit = MINOR(dev) >> MdpMinorShift;
5227 		} else {
5228 			dev = MKDEV(MD_MAJOR, rdev0->preferred_minor);
5229 			unit = MINOR(dev);
5230 		}
5231 		if (rdev0->preferred_minor != unit) {
5232 			printk(KERN_INFO "md: unit number in %s is bad: %d\n",
5233 			       bdevname(rdev0->bdev, b), rdev0->preferred_minor);
5234 			break;
5235 		}
5236 
5237 		md_probe(dev, NULL, NULL);
5238 		mddev = mddev_find(dev);
5239 		if (!mddev || !mddev->gendisk) {
5240 			if (mddev)
5241 				mddev_put(mddev);
5242 			printk(KERN_ERR
5243 				"md: cannot allocate memory for md drive.\n");
5244 			break;
5245 		}
5246 		if (mddev_lock(mddev))
5247 			printk(KERN_WARNING "md: %s locked, cannot run\n",
5248 			       mdname(mddev));
5249 		else if (mddev->raid_disks || mddev->major_version
5250 			 || !list_empty(&mddev->disks)) {
5251 			printk(KERN_WARNING
5252 				"md: %s already running, cannot run %s\n",
5253 				mdname(mddev), bdevname(rdev0->bdev,b));
5254 			mddev_unlock(mddev);
5255 		} else {
5256 			printk(KERN_INFO "md: created %s\n", mdname(mddev));
5257 			mddev->persistent = 1;
5258 			rdev_for_each_list(rdev, tmp, &candidates) {
5259 				list_del_init(&rdev->same_set);
5260 				if (bind_rdev_to_array(rdev, mddev))
5261 					export_rdev(rdev);
5262 			}
5263 			autorun_array(mddev);
5264 			mddev_unlock(mddev);
5265 		}
5266 		/* on success, candidates will be empty, on error
5267 		 * it won't...
5268 		 */
5269 		rdev_for_each_list(rdev, tmp, &candidates) {
5270 			list_del_init(&rdev->same_set);
5271 			export_rdev(rdev);
5272 		}
5273 		mddev_put(mddev);
5274 	}
5275 	printk(KERN_INFO "md: ... autorun DONE.\n");
5276 }
5277 #endif /* !MODULE */
5278 
5279 static int get_version(void __user * arg)
5280 {
5281 	mdu_version_t ver;
5282 
5283 	ver.major = MD_MAJOR_VERSION;
5284 	ver.minor = MD_MINOR_VERSION;
5285 	ver.patchlevel = MD_PATCHLEVEL_VERSION;
5286 
5287 	if (copy_to_user(arg, &ver, sizeof(ver)))
5288 		return -EFAULT;
5289 
5290 	return 0;
5291 }
5292 
5293 static int get_array_info(struct mddev * mddev, void __user * arg)
5294 {
5295 	mdu_array_info_t info;
5296 	int nr,working,insync,failed,spare;
5297 	struct md_rdev *rdev;
5298 
5299 	nr=working=insync=failed=spare=0;
5300 	list_for_each_entry(rdev, &mddev->disks, same_set) {
5301 		nr++;
5302 		if (test_bit(Faulty, &rdev->flags))
5303 			failed++;
5304 		else {
5305 			working++;
5306 			if (test_bit(In_sync, &rdev->flags))
5307 				insync++;
5308 			else
5309 				spare++;
5310 		}
5311 	}
5312 
5313 	info.major_version = mddev->major_version;
5314 	info.minor_version = mddev->minor_version;
5315 	info.patch_version = MD_PATCHLEVEL_VERSION;
5316 	info.ctime         = mddev->ctime;
5317 	info.level         = mddev->level;
5318 	info.size          = mddev->dev_sectors / 2;
5319 	if (info.size != mddev->dev_sectors / 2) /* overflow */
5320 		info.size = -1;
5321 	info.nr_disks      = nr;
5322 	info.raid_disks    = mddev->raid_disks;
5323 	info.md_minor      = mddev->md_minor;
5324 	info.not_persistent= !mddev->persistent;
5325 
5326 	info.utime         = mddev->utime;
5327 	info.state         = 0;
5328 	if (mddev->in_sync)
5329 		info.state = (1<<MD_SB_CLEAN);
5330 	if (mddev->bitmap && mddev->bitmap_info.offset)
5331 		info.state = (1<<MD_SB_BITMAP_PRESENT);
5332 	info.active_disks  = insync;
5333 	info.working_disks = working;
5334 	info.failed_disks  = failed;
5335 	info.spare_disks   = spare;
5336 
5337 	info.layout        = mddev->layout;
5338 	info.chunk_size    = mddev->chunk_sectors << 9;
5339 
5340 	if (copy_to_user(arg, &info, sizeof(info)))
5341 		return -EFAULT;
5342 
5343 	return 0;
5344 }
5345 
5346 static int get_bitmap_file(struct mddev * mddev, void __user * arg)
5347 {
5348 	mdu_bitmap_file_t *file = NULL; /* too big for stack allocation */
5349 	char *ptr, *buf = NULL;
5350 	int err = -ENOMEM;
5351 
5352 	if (md_allow_write(mddev))
5353 		file = kmalloc(sizeof(*file), GFP_NOIO);
5354 	else
5355 		file = kmalloc(sizeof(*file), GFP_KERNEL);
5356 
5357 	if (!file)
5358 		goto out;
5359 
5360 	/* bitmap disabled, zero the first byte and copy out */
5361 	if (!mddev->bitmap || !mddev->bitmap->file) {
5362 		file->pathname[0] = '\0';
5363 		goto copy_out;
5364 	}
5365 
5366 	buf = kmalloc(sizeof(file->pathname), GFP_KERNEL);
5367 	if (!buf)
5368 		goto out;
5369 
5370 	ptr = d_path(&mddev->bitmap->file->f_path, buf, sizeof(file->pathname));
5371 	if (IS_ERR(ptr))
5372 		goto out;
5373 
5374 	strcpy(file->pathname, ptr);
5375 
5376 copy_out:
5377 	err = 0;
5378 	if (copy_to_user(arg, file, sizeof(*file)))
5379 		err = -EFAULT;
5380 out:
5381 	kfree(buf);
5382 	kfree(file);
5383 	return err;
5384 }
5385 
5386 static int get_disk_info(struct mddev * mddev, void __user * arg)
5387 {
5388 	mdu_disk_info_t info;
5389 	struct md_rdev *rdev;
5390 
5391 	if (copy_from_user(&info, arg, sizeof(info)))
5392 		return -EFAULT;
5393 
5394 	rdev = find_rdev_nr(mddev, info.number);
5395 	if (rdev) {
5396 		info.major = MAJOR(rdev->bdev->bd_dev);
5397 		info.minor = MINOR(rdev->bdev->bd_dev);
5398 		info.raid_disk = rdev->raid_disk;
5399 		info.state = 0;
5400 		if (test_bit(Faulty, &rdev->flags))
5401 			info.state |= (1<<MD_DISK_FAULTY);
5402 		else if (test_bit(In_sync, &rdev->flags)) {
5403 			info.state |= (1<<MD_DISK_ACTIVE);
5404 			info.state |= (1<<MD_DISK_SYNC);
5405 		}
5406 		if (test_bit(WriteMostly, &rdev->flags))
5407 			info.state |= (1<<MD_DISK_WRITEMOSTLY);
5408 	} else {
5409 		info.major = info.minor = 0;
5410 		info.raid_disk = -1;
5411 		info.state = (1<<MD_DISK_REMOVED);
5412 	}
5413 
5414 	if (copy_to_user(arg, &info, sizeof(info)))
5415 		return -EFAULT;
5416 
5417 	return 0;
5418 }
5419 
5420 static int add_new_disk(struct mddev * mddev, mdu_disk_info_t *info)
5421 {
5422 	char b[BDEVNAME_SIZE], b2[BDEVNAME_SIZE];
5423 	struct md_rdev *rdev;
5424 	dev_t dev = MKDEV(info->major,info->minor);
5425 
5426 	if (info->major != MAJOR(dev) || info->minor != MINOR(dev))
5427 		return -EOVERFLOW;
5428 
5429 	if (!mddev->raid_disks) {
5430 		int err;
5431 		/* expecting a device which has a superblock */
5432 		rdev = md_import_device(dev, mddev->major_version, mddev->minor_version);
5433 		if (IS_ERR(rdev)) {
5434 			printk(KERN_WARNING
5435 				"md: md_import_device returned %ld\n",
5436 				PTR_ERR(rdev));
5437 			return PTR_ERR(rdev);
5438 		}
5439 		if (!list_empty(&mddev->disks)) {
5440 			struct md_rdev *rdev0
5441 				= list_entry(mddev->disks.next,
5442 					     struct md_rdev, same_set);
5443 			err = super_types[mddev->major_version]
5444 				.load_super(rdev, rdev0, mddev->minor_version);
5445 			if (err < 0) {
5446 				printk(KERN_WARNING
5447 					"md: %s has different UUID to %s\n",
5448 					bdevname(rdev->bdev,b),
5449 					bdevname(rdev0->bdev,b2));
5450 				export_rdev(rdev);
5451 				return -EINVAL;
5452 			}
5453 		}
5454 		err = bind_rdev_to_array(rdev, mddev);
5455 		if (err)
5456 			export_rdev(rdev);
5457 		return err;
5458 	}
5459 
5460 	/*
5461 	 * add_new_disk can be used once the array is assembled
5462 	 * to add "hot spares".  They must already have a superblock
5463 	 * written
5464 	 */
5465 	if (mddev->pers) {
5466 		int err;
5467 		if (!mddev->pers->hot_add_disk) {
5468 			printk(KERN_WARNING
5469 				"%s: personality does not support diskops!\n",
5470 			       mdname(mddev));
5471 			return -EINVAL;
5472 		}
5473 		if (mddev->persistent)
5474 			rdev = md_import_device(dev, mddev->major_version,
5475 						mddev->minor_version);
5476 		else
5477 			rdev = md_import_device(dev, -1, -1);
5478 		if (IS_ERR(rdev)) {
5479 			printk(KERN_WARNING
5480 				"md: md_import_device returned %ld\n",
5481 				PTR_ERR(rdev));
5482 			return PTR_ERR(rdev);
5483 		}
5484 		/* set saved_raid_disk if appropriate */
5485 		if (!mddev->persistent) {
5486 			if (info->state & (1<<MD_DISK_SYNC)  &&
5487 			    info->raid_disk < mddev->raid_disks) {
5488 				rdev->raid_disk = info->raid_disk;
5489 				set_bit(In_sync, &rdev->flags);
5490 			} else
5491 				rdev->raid_disk = -1;
5492 		} else
5493 			super_types[mddev->major_version].
5494 				validate_super(mddev, rdev);
5495 		if ((info->state & (1<<MD_DISK_SYNC)) &&
5496 		    (!test_bit(In_sync, &rdev->flags) ||
5497 		     rdev->raid_disk != info->raid_disk)) {
5498 			/* This was a hot-add request, but events doesn't
5499 			 * match, so reject it.
5500 			 */
5501 			export_rdev(rdev);
5502 			return -EINVAL;
5503 		}
5504 
5505 		if (test_bit(In_sync, &rdev->flags))
5506 			rdev->saved_raid_disk = rdev->raid_disk;
5507 		else
5508 			rdev->saved_raid_disk = -1;
5509 
5510 		clear_bit(In_sync, &rdev->flags); /* just to be sure */
5511 		if (info->state & (1<<MD_DISK_WRITEMOSTLY))
5512 			set_bit(WriteMostly, &rdev->flags);
5513 		else
5514 			clear_bit(WriteMostly, &rdev->flags);
5515 
5516 		rdev->raid_disk = -1;
5517 		err = bind_rdev_to_array(rdev, mddev);
5518 		if (!err && !mddev->pers->hot_remove_disk) {
5519 			/* If there is hot_add_disk but no hot_remove_disk
5520 			 * then added disks for geometry changes,
5521 			 * and should be added immediately.
5522 			 */
5523 			super_types[mddev->major_version].
5524 				validate_super(mddev, rdev);
5525 			err = mddev->pers->hot_add_disk(mddev, rdev);
5526 			if (err)
5527 				unbind_rdev_from_array(rdev);
5528 		}
5529 		if (err)
5530 			export_rdev(rdev);
5531 		else
5532 			sysfs_notify_dirent_safe(rdev->sysfs_state);
5533 
5534 		md_update_sb(mddev, 1);
5535 		if (mddev->degraded)
5536 			set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
5537 		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
5538 		if (!err)
5539 			md_new_event(mddev);
5540 		md_wakeup_thread(mddev->thread);
5541 		return err;
5542 	}
5543 
5544 	/* otherwise, add_new_disk is only allowed
5545 	 * for major_version==0 superblocks
5546 	 */
5547 	if (mddev->major_version != 0) {
5548 		printk(KERN_WARNING "%s: ADD_NEW_DISK not supported\n",
5549 		       mdname(mddev));
5550 		return -EINVAL;
5551 	}
5552 
5553 	if (!(info->state & (1<<MD_DISK_FAULTY))) {
5554 		int err;
5555 		rdev = md_import_device(dev, -1, 0);
5556 		if (IS_ERR(rdev)) {
5557 			printk(KERN_WARNING
5558 				"md: error, md_import_device() returned %ld\n",
5559 				PTR_ERR(rdev));
5560 			return PTR_ERR(rdev);
5561 		}
5562 		rdev->desc_nr = info->number;
5563 		if (info->raid_disk < mddev->raid_disks)
5564 			rdev->raid_disk = info->raid_disk;
5565 		else
5566 			rdev->raid_disk = -1;
5567 
5568 		if (rdev->raid_disk < mddev->raid_disks)
5569 			if (info->state & (1<<MD_DISK_SYNC))
5570 				set_bit(In_sync, &rdev->flags);
5571 
5572 		if (info->state & (1<<MD_DISK_WRITEMOSTLY))
5573 			set_bit(WriteMostly, &rdev->flags);
5574 
5575 		if (!mddev->persistent) {
5576 			printk(KERN_INFO "md: nonpersistent superblock ...\n");
5577 			rdev->sb_start = i_size_read(rdev->bdev->bd_inode) / 512;
5578 		} else
5579 			rdev->sb_start = calc_dev_sboffset(rdev);
5580 		rdev->sectors = rdev->sb_start;
5581 
5582 		err = bind_rdev_to_array(rdev, mddev);
5583 		if (err) {
5584 			export_rdev(rdev);
5585 			return err;
5586 		}
5587 	}
5588 
5589 	return 0;
5590 }
5591 
5592 static int hot_remove_disk(struct mddev * mddev, dev_t dev)
5593 {
5594 	char b[BDEVNAME_SIZE];
5595 	struct md_rdev *rdev;
5596 
5597 	rdev = find_rdev(mddev, dev);
5598 	if (!rdev)
5599 		return -ENXIO;
5600 
5601 	if (rdev->raid_disk >= 0)
5602 		goto busy;
5603 
5604 	kick_rdev_from_array(rdev);
5605 	md_update_sb(mddev, 1);
5606 	md_new_event(mddev);
5607 
5608 	return 0;
5609 busy:
5610 	printk(KERN_WARNING "md: cannot remove active disk %s from %s ...\n",
5611 		bdevname(rdev->bdev,b), mdname(mddev));
5612 	return -EBUSY;
5613 }
5614 
5615 static int hot_add_disk(struct mddev * mddev, dev_t dev)
5616 {
5617 	char b[BDEVNAME_SIZE];
5618 	int err;
5619 	struct md_rdev *rdev;
5620 
5621 	if (!mddev->pers)
5622 		return -ENODEV;
5623 
5624 	if (mddev->major_version != 0) {
5625 		printk(KERN_WARNING "%s: HOT_ADD may only be used with"
5626 			" version-0 superblocks.\n",
5627 			mdname(mddev));
5628 		return -EINVAL;
5629 	}
5630 	if (!mddev->pers->hot_add_disk) {
5631 		printk(KERN_WARNING
5632 			"%s: personality does not support diskops!\n",
5633 			mdname(mddev));
5634 		return -EINVAL;
5635 	}
5636 
5637 	rdev = md_import_device(dev, -1, 0);
5638 	if (IS_ERR(rdev)) {
5639 		printk(KERN_WARNING
5640 			"md: error, md_import_device() returned %ld\n",
5641 			PTR_ERR(rdev));
5642 		return -EINVAL;
5643 	}
5644 
5645 	if (mddev->persistent)
5646 		rdev->sb_start = calc_dev_sboffset(rdev);
5647 	else
5648 		rdev->sb_start = i_size_read(rdev->bdev->bd_inode) / 512;
5649 
5650 	rdev->sectors = rdev->sb_start;
5651 
5652 	if (test_bit(Faulty, &rdev->flags)) {
5653 		printk(KERN_WARNING
5654 			"md: can not hot-add faulty %s disk to %s!\n",
5655 			bdevname(rdev->bdev,b), mdname(mddev));
5656 		err = -EINVAL;
5657 		goto abort_export;
5658 	}
5659 	clear_bit(In_sync, &rdev->flags);
5660 	rdev->desc_nr = -1;
5661 	rdev->saved_raid_disk = -1;
5662 	err = bind_rdev_to_array(rdev, mddev);
5663 	if (err)
5664 		goto abort_export;
5665 
5666 	/*
5667 	 * The rest should better be atomic, we can have disk failures
5668 	 * noticed in interrupt contexts ...
5669 	 */
5670 
5671 	rdev->raid_disk = -1;
5672 
5673 	md_update_sb(mddev, 1);
5674 
5675 	/*
5676 	 * Kick recovery, maybe this spare has to be added to the
5677 	 * array immediately.
5678 	 */
5679 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
5680 	md_wakeup_thread(mddev->thread);
5681 	md_new_event(mddev);
5682 	return 0;
5683 
5684 abort_export:
5685 	export_rdev(rdev);
5686 	return err;
5687 }
5688 
5689 static int set_bitmap_file(struct mddev *mddev, int fd)
5690 {
5691 	int err;
5692 
5693 	if (mddev->pers) {
5694 		if (!mddev->pers->quiesce)
5695 			return -EBUSY;
5696 		if (mddev->recovery || mddev->sync_thread)
5697 			return -EBUSY;
5698 		/* we should be able to change the bitmap.. */
5699 	}
5700 
5701 
5702 	if (fd >= 0) {
5703 		if (mddev->bitmap)
5704 			return -EEXIST; /* cannot add when bitmap is present */
5705 		mddev->bitmap_info.file = fget(fd);
5706 
5707 		if (mddev->bitmap_info.file == NULL) {
5708 			printk(KERN_ERR "%s: error: failed to get bitmap file\n",
5709 			       mdname(mddev));
5710 			return -EBADF;
5711 		}
5712 
5713 		err = deny_bitmap_write_access(mddev->bitmap_info.file);
5714 		if (err) {
5715 			printk(KERN_ERR "%s: error: bitmap file is already in use\n",
5716 			       mdname(mddev));
5717 			fput(mddev->bitmap_info.file);
5718 			mddev->bitmap_info.file = NULL;
5719 			return err;
5720 		}
5721 		mddev->bitmap_info.offset = 0; /* file overrides offset */
5722 	} else if (mddev->bitmap == NULL)
5723 		return -ENOENT; /* cannot remove what isn't there */
5724 	err = 0;
5725 	if (mddev->pers) {
5726 		mddev->pers->quiesce(mddev, 1);
5727 		if (fd >= 0) {
5728 			err = bitmap_create(mddev);
5729 			if (!err)
5730 				err = bitmap_load(mddev);
5731 		}
5732 		if (fd < 0 || err) {
5733 			bitmap_destroy(mddev);
5734 			fd = -1; /* make sure to put the file */
5735 		}
5736 		mddev->pers->quiesce(mddev, 0);
5737 	}
5738 	if (fd < 0) {
5739 		if (mddev->bitmap_info.file) {
5740 			restore_bitmap_write_access(mddev->bitmap_info.file);
5741 			fput(mddev->bitmap_info.file);
5742 		}
5743 		mddev->bitmap_info.file = NULL;
5744 	}
5745 
5746 	return err;
5747 }
5748 
5749 /*
5750  * set_array_info is used two different ways
5751  * The original usage is when creating a new array.
5752  * In this usage, raid_disks is > 0 and it together with
5753  *  level, size, not_persistent,layout,chunksize determine the
5754  *  shape of the array.
5755  *  This will always create an array with a type-0.90.0 superblock.
5756  * The newer usage is when assembling an array.
5757  *  In this case raid_disks will be 0, and the major_version field is
5758  *  use to determine which style super-blocks are to be found on the devices.
5759  *  The minor and patch _version numbers are also kept incase the
5760  *  super_block handler wishes to interpret them.
5761  */
5762 static int set_array_info(struct mddev * mddev, mdu_array_info_t *info)
5763 {
5764 
5765 	if (info->raid_disks == 0) {
5766 		/* just setting version number for superblock loading */
5767 		if (info->major_version < 0 ||
5768 		    info->major_version >= ARRAY_SIZE(super_types) ||
5769 		    super_types[info->major_version].name == NULL) {
5770 			/* maybe try to auto-load a module? */
5771 			printk(KERN_INFO
5772 				"md: superblock version %d not known\n",
5773 				info->major_version);
5774 			return -EINVAL;
5775 		}
5776 		mddev->major_version = info->major_version;
5777 		mddev->minor_version = info->minor_version;
5778 		mddev->patch_version = info->patch_version;
5779 		mddev->persistent = !info->not_persistent;
5780 		/* ensure mddev_put doesn't delete this now that there
5781 		 * is some minimal configuration.
5782 		 */
5783 		mddev->ctime         = get_seconds();
5784 		return 0;
5785 	}
5786 	mddev->major_version = MD_MAJOR_VERSION;
5787 	mddev->minor_version = MD_MINOR_VERSION;
5788 	mddev->patch_version = MD_PATCHLEVEL_VERSION;
5789 	mddev->ctime         = get_seconds();
5790 
5791 	mddev->level         = info->level;
5792 	mddev->clevel[0]     = 0;
5793 	mddev->dev_sectors   = 2 * (sector_t)info->size;
5794 	mddev->raid_disks    = info->raid_disks;
5795 	/* don't set md_minor, it is determined by which /dev/md* was
5796 	 * openned
5797 	 */
5798 	if (info->state & (1<<MD_SB_CLEAN))
5799 		mddev->recovery_cp = MaxSector;
5800 	else
5801 		mddev->recovery_cp = 0;
5802 	mddev->persistent    = ! info->not_persistent;
5803 	mddev->external	     = 0;
5804 
5805 	mddev->layout        = info->layout;
5806 	mddev->chunk_sectors = info->chunk_size >> 9;
5807 
5808 	mddev->max_disks     = MD_SB_DISKS;
5809 
5810 	if (mddev->persistent)
5811 		mddev->flags         = 0;
5812 	set_bit(MD_CHANGE_DEVS, &mddev->flags);
5813 
5814 	mddev->bitmap_info.default_offset = MD_SB_BYTES >> 9;
5815 	mddev->bitmap_info.offset = 0;
5816 
5817 	mddev->reshape_position = MaxSector;
5818 
5819 	/*
5820 	 * Generate a 128 bit UUID
5821 	 */
5822 	get_random_bytes(mddev->uuid, 16);
5823 
5824 	mddev->new_level = mddev->level;
5825 	mddev->new_chunk_sectors = mddev->chunk_sectors;
5826 	mddev->new_layout = mddev->layout;
5827 	mddev->delta_disks = 0;
5828 
5829 	return 0;
5830 }
5831 
5832 void md_set_array_sectors(struct mddev *mddev, sector_t array_sectors)
5833 {
5834 	WARN(!mddev_is_locked(mddev), "%s: unlocked mddev!\n", __func__);
5835 
5836 	if (mddev->external_size)
5837 		return;
5838 
5839 	mddev->array_sectors = array_sectors;
5840 }
5841 EXPORT_SYMBOL(md_set_array_sectors);
5842 
5843 static int update_size(struct mddev *mddev, sector_t num_sectors)
5844 {
5845 	struct md_rdev *rdev;
5846 	int rv;
5847 	int fit = (num_sectors == 0);
5848 
5849 	if (mddev->pers->resize == NULL)
5850 		return -EINVAL;
5851 	/* The "num_sectors" is the number of sectors of each device that
5852 	 * is used.  This can only make sense for arrays with redundancy.
5853 	 * linear and raid0 always use whatever space is available. We can only
5854 	 * consider changing this number if no resync or reconstruction is
5855 	 * happening, and if the new size is acceptable. It must fit before the
5856 	 * sb_start or, if that is <data_offset, it must fit before the size
5857 	 * of each device.  If num_sectors is zero, we find the largest size
5858 	 * that fits.
5859 	 */
5860 	if (mddev->sync_thread)
5861 		return -EBUSY;
5862 	if (mddev->bitmap)
5863 		/* Sorry, cannot grow a bitmap yet, just remove it,
5864 		 * grow, and re-add.
5865 		 */
5866 		return -EBUSY;
5867 	list_for_each_entry(rdev, &mddev->disks, same_set) {
5868 		sector_t avail = rdev->sectors;
5869 
5870 		if (fit && (num_sectors == 0 || num_sectors > avail))
5871 			num_sectors = avail;
5872 		if (avail < num_sectors)
5873 			return -ENOSPC;
5874 	}
5875 	rv = mddev->pers->resize(mddev, num_sectors);
5876 	if (!rv)
5877 		revalidate_disk(mddev->gendisk);
5878 	return rv;
5879 }
5880 
5881 static int update_raid_disks(struct mddev *mddev, int raid_disks)
5882 {
5883 	int rv;
5884 	/* change the number of raid disks */
5885 	if (mddev->pers->check_reshape == NULL)
5886 		return -EINVAL;
5887 	if (raid_disks <= 0 ||
5888 	    (mddev->max_disks && raid_disks >= mddev->max_disks))
5889 		return -EINVAL;
5890 	if (mddev->sync_thread || mddev->reshape_position != MaxSector)
5891 		return -EBUSY;
5892 	mddev->delta_disks = raid_disks - mddev->raid_disks;
5893 
5894 	rv = mddev->pers->check_reshape(mddev);
5895 	if (rv < 0)
5896 		mddev->delta_disks = 0;
5897 	return rv;
5898 }
5899 
5900 
5901 /*
5902  * update_array_info is used to change the configuration of an
5903  * on-line array.
5904  * The version, ctime,level,size,raid_disks,not_persistent, layout,chunk_size
5905  * fields in the info are checked against the array.
5906  * Any differences that cannot be handled will cause an error.
5907  * Normally, only one change can be managed at a time.
5908  */
5909 static int update_array_info(struct mddev *mddev, mdu_array_info_t *info)
5910 {
5911 	int rv = 0;
5912 	int cnt = 0;
5913 	int state = 0;
5914 
5915 	/* calculate expected state,ignoring low bits */
5916 	if (mddev->bitmap && mddev->bitmap_info.offset)
5917 		state |= (1 << MD_SB_BITMAP_PRESENT);
5918 
5919 	if (mddev->major_version != info->major_version ||
5920 	    mddev->minor_version != info->minor_version ||
5921 /*	    mddev->patch_version != info->patch_version || */
5922 	    mddev->ctime         != info->ctime         ||
5923 	    mddev->level         != info->level         ||
5924 /*	    mddev->layout        != info->layout        || */
5925 	    !mddev->persistent	 != info->not_persistent||
5926 	    mddev->chunk_sectors != info->chunk_size >> 9 ||
5927 	    /* ignore bottom 8 bits of state, and allow SB_BITMAP_PRESENT to change */
5928 	    ((state^info->state) & 0xfffffe00)
5929 		)
5930 		return -EINVAL;
5931 	/* Check there is only one change */
5932 	if (info->size >= 0 && mddev->dev_sectors / 2 != info->size)
5933 		cnt++;
5934 	if (mddev->raid_disks != info->raid_disks)
5935 		cnt++;
5936 	if (mddev->layout != info->layout)
5937 		cnt++;
5938 	if ((state ^ info->state) & (1<<MD_SB_BITMAP_PRESENT))
5939 		cnt++;
5940 	if (cnt == 0)
5941 		return 0;
5942 	if (cnt > 1)
5943 		return -EINVAL;
5944 
5945 	if (mddev->layout != info->layout) {
5946 		/* Change layout
5947 		 * we don't need to do anything at the md level, the
5948 		 * personality will take care of it all.
5949 		 */
5950 		if (mddev->pers->check_reshape == NULL)
5951 			return -EINVAL;
5952 		else {
5953 			mddev->new_layout = info->layout;
5954 			rv = mddev->pers->check_reshape(mddev);
5955 			if (rv)
5956 				mddev->new_layout = mddev->layout;
5957 			return rv;
5958 		}
5959 	}
5960 	if (info->size >= 0 && mddev->dev_sectors / 2 != info->size)
5961 		rv = update_size(mddev, (sector_t)info->size * 2);
5962 
5963 	if (mddev->raid_disks    != info->raid_disks)
5964 		rv = update_raid_disks(mddev, info->raid_disks);
5965 
5966 	if ((state ^ info->state) & (1<<MD_SB_BITMAP_PRESENT)) {
5967 		if (mddev->pers->quiesce == NULL)
5968 			return -EINVAL;
5969 		if (mddev->recovery || mddev->sync_thread)
5970 			return -EBUSY;
5971 		if (info->state & (1<<MD_SB_BITMAP_PRESENT)) {
5972 			/* add the bitmap */
5973 			if (mddev->bitmap)
5974 				return -EEXIST;
5975 			if (mddev->bitmap_info.default_offset == 0)
5976 				return -EINVAL;
5977 			mddev->bitmap_info.offset =
5978 				mddev->bitmap_info.default_offset;
5979 			mddev->pers->quiesce(mddev, 1);
5980 			rv = bitmap_create(mddev);
5981 			if (!rv)
5982 				rv = bitmap_load(mddev);
5983 			if (rv)
5984 				bitmap_destroy(mddev);
5985 			mddev->pers->quiesce(mddev, 0);
5986 		} else {
5987 			/* remove the bitmap */
5988 			if (!mddev->bitmap)
5989 				return -ENOENT;
5990 			if (mddev->bitmap->file)
5991 				return -EINVAL;
5992 			mddev->pers->quiesce(mddev, 1);
5993 			bitmap_destroy(mddev);
5994 			mddev->pers->quiesce(mddev, 0);
5995 			mddev->bitmap_info.offset = 0;
5996 		}
5997 	}
5998 	md_update_sb(mddev, 1);
5999 	return rv;
6000 }
6001 
6002 static int set_disk_faulty(struct mddev *mddev, dev_t dev)
6003 {
6004 	struct md_rdev *rdev;
6005 
6006 	if (mddev->pers == NULL)
6007 		return -ENODEV;
6008 
6009 	rdev = find_rdev(mddev, dev);
6010 	if (!rdev)
6011 		return -ENODEV;
6012 
6013 	md_error(mddev, rdev);
6014 	if (!test_bit(Faulty, &rdev->flags))
6015 		return -EBUSY;
6016 	return 0;
6017 }
6018 
6019 /*
6020  * We have a problem here : there is no easy way to give a CHS
6021  * virtual geometry. We currently pretend that we have a 2 heads
6022  * 4 sectors (with a BIG number of cylinders...). This drives
6023  * dosfs just mad... ;-)
6024  */
6025 static int md_getgeo(struct block_device *bdev, struct hd_geometry *geo)
6026 {
6027 	struct mddev *mddev = bdev->bd_disk->private_data;
6028 
6029 	geo->heads = 2;
6030 	geo->sectors = 4;
6031 	geo->cylinders = mddev->array_sectors / 8;
6032 	return 0;
6033 }
6034 
6035 static int md_ioctl(struct block_device *bdev, fmode_t mode,
6036 			unsigned int cmd, unsigned long arg)
6037 {
6038 	int err = 0;
6039 	void __user *argp = (void __user *)arg;
6040 	struct mddev *mddev = NULL;
6041 	int ro;
6042 
6043 	if (!capable(CAP_SYS_ADMIN))
6044 		return -EACCES;
6045 
6046 	/*
6047 	 * Commands dealing with the RAID driver but not any
6048 	 * particular array:
6049 	 */
6050 	switch (cmd)
6051 	{
6052 		case RAID_VERSION:
6053 			err = get_version(argp);
6054 			goto done;
6055 
6056 		case PRINT_RAID_DEBUG:
6057 			err = 0;
6058 			md_print_devices();
6059 			goto done;
6060 
6061 #ifndef MODULE
6062 		case RAID_AUTORUN:
6063 			err = 0;
6064 			autostart_arrays(arg);
6065 			goto done;
6066 #endif
6067 		default:;
6068 	}
6069 
6070 	/*
6071 	 * Commands creating/starting a new array:
6072 	 */
6073 
6074 	mddev = bdev->bd_disk->private_data;
6075 
6076 	if (!mddev) {
6077 		BUG();
6078 		goto abort;
6079 	}
6080 
6081 	err = mddev_lock(mddev);
6082 	if (err) {
6083 		printk(KERN_INFO
6084 			"md: ioctl lock interrupted, reason %d, cmd %d\n",
6085 			err, cmd);
6086 		goto abort;
6087 	}
6088 
6089 	switch (cmd)
6090 	{
6091 		case SET_ARRAY_INFO:
6092 			{
6093 				mdu_array_info_t info;
6094 				if (!arg)
6095 					memset(&info, 0, sizeof(info));
6096 				else if (copy_from_user(&info, argp, sizeof(info))) {
6097 					err = -EFAULT;
6098 					goto abort_unlock;
6099 				}
6100 				if (mddev->pers) {
6101 					err = update_array_info(mddev, &info);
6102 					if (err) {
6103 						printk(KERN_WARNING "md: couldn't update"
6104 						       " array info. %d\n", err);
6105 						goto abort_unlock;
6106 					}
6107 					goto done_unlock;
6108 				}
6109 				if (!list_empty(&mddev->disks)) {
6110 					printk(KERN_WARNING
6111 					       "md: array %s already has disks!\n",
6112 					       mdname(mddev));
6113 					err = -EBUSY;
6114 					goto abort_unlock;
6115 				}
6116 				if (mddev->raid_disks) {
6117 					printk(KERN_WARNING
6118 					       "md: array %s already initialised!\n",
6119 					       mdname(mddev));
6120 					err = -EBUSY;
6121 					goto abort_unlock;
6122 				}
6123 				err = set_array_info(mddev, &info);
6124 				if (err) {
6125 					printk(KERN_WARNING "md: couldn't set"
6126 					       " array info. %d\n", err);
6127 					goto abort_unlock;
6128 				}
6129 			}
6130 			goto done_unlock;
6131 
6132 		default:;
6133 	}
6134 
6135 	/*
6136 	 * Commands querying/configuring an existing array:
6137 	 */
6138 	/* if we are not initialised yet, only ADD_NEW_DISK, STOP_ARRAY,
6139 	 * RUN_ARRAY, and GET_ and SET_BITMAP_FILE are allowed */
6140 	if ((!mddev->raid_disks && !mddev->external)
6141 	    && cmd != ADD_NEW_DISK && cmd != STOP_ARRAY
6142 	    && cmd != RUN_ARRAY && cmd != SET_BITMAP_FILE
6143 	    && cmd != GET_BITMAP_FILE) {
6144 		err = -ENODEV;
6145 		goto abort_unlock;
6146 	}
6147 
6148 	/*
6149 	 * Commands even a read-only array can execute:
6150 	 */
6151 	switch (cmd)
6152 	{
6153 		case GET_ARRAY_INFO:
6154 			err = get_array_info(mddev, argp);
6155 			goto done_unlock;
6156 
6157 		case GET_BITMAP_FILE:
6158 			err = get_bitmap_file(mddev, argp);
6159 			goto done_unlock;
6160 
6161 		case GET_DISK_INFO:
6162 			err = get_disk_info(mddev, argp);
6163 			goto done_unlock;
6164 
6165 		case RESTART_ARRAY_RW:
6166 			err = restart_array(mddev);
6167 			goto done_unlock;
6168 
6169 		case STOP_ARRAY:
6170 			err = do_md_stop(mddev, 0, 1);
6171 			goto done_unlock;
6172 
6173 		case STOP_ARRAY_RO:
6174 			err = md_set_readonly(mddev, 1);
6175 			goto done_unlock;
6176 
6177 		case BLKROSET:
6178 			if (get_user(ro, (int __user *)(arg))) {
6179 				err = -EFAULT;
6180 				goto done_unlock;
6181 			}
6182 			err = -EINVAL;
6183 
6184 			/* if the bdev is going readonly the value of mddev->ro
6185 			 * does not matter, no writes are coming
6186 			 */
6187 			if (ro)
6188 				goto done_unlock;
6189 
6190 			/* are we are already prepared for writes? */
6191 			if (mddev->ro != 1)
6192 				goto done_unlock;
6193 
6194 			/* transitioning to readauto need only happen for
6195 			 * arrays that call md_write_start
6196 			 */
6197 			if (mddev->pers) {
6198 				err = restart_array(mddev);
6199 				if (err == 0) {
6200 					mddev->ro = 2;
6201 					set_disk_ro(mddev->gendisk, 0);
6202 				}
6203 			}
6204 			goto done_unlock;
6205 	}
6206 
6207 	/*
6208 	 * The remaining ioctls are changing the state of the
6209 	 * superblock, so we do not allow them on read-only arrays.
6210 	 * However non-MD ioctls (e.g. get-size) will still come through
6211 	 * here and hit the 'default' below, so only disallow
6212 	 * 'md' ioctls, and switch to rw mode if started auto-readonly.
6213 	 */
6214 	if (_IOC_TYPE(cmd) == MD_MAJOR && mddev->ro && mddev->pers) {
6215 		if (mddev->ro == 2) {
6216 			mddev->ro = 0;
6217 			sysfs_notify_dirent_safe(mddev->sysfs_state);
6218 			set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
6219 			md_wakeup_thread(mddev->thread);
6220 		} else {
6221 			err = -EROFS;
6222 			goto abort_unlock;
6223 		}
6224 	}
6225 
6226 	switch (cmd)
6227 	{
6228 		case ADD_NEW_DISK:
6229 		{
6230 			mdu_disk_info_t info;
6231 			if (copy_from_user(&info, argp, sizeof(info)))
6232 				err = -EFAULT;
6233 			else
6234 				err = add_new_disk(mddev, &info);
6235 			goto done_unlock;
6236 		}
6237 
6238 		case HOT_REMOVE_DISK:
6239 			err = hot_remove_disk(mddev, new_decode_dev(arg));
6240 			goto done_unlock;
6241 
6242 		case HOT_ADD_DISK:
6243 			err = hot_add_disk(mddev, new_decode_dev(arg));
6244 			goto done_unlock;
6245 
6246 		case SET_DISK_FAULTY:
6247 			err = set_disk_faulty(mddev, new_decode_dev(arg));
6248 			goto done_unlock;
6249 
6250 		case RUN_ARRAY:
6251 			err = do_md_run(mddev);
6252 			goto done_unlock;
6253 
6254 		case SET_BITMAP_FILE:
6255 			err = set_bitmap_file(mddev, (int)arg);
6256 			goto done_unlock;
6257 
6258 		default:
6259 			err = -EINVAL;
6260 			goto abort_unlock;
6261 	}
6262 
6263 done_unlock:
6264 abort_unlock:
6265 	if (mddev->hold_active == UNTIL_IOCTL &&
6266 	    err != -EINVAL)
6267 		mddev->hold_active = 0;
6268 	mddev_unlock(mddev);
6269 
6270 	return err;
6271 done:
6272 	if (err)
6273 		MD_BUG();
6274 abort:
6275 	return err;
6276 }
6277 #ifdef CONFIG_COMPAT
6278 static int md_compat_ioctl(struct block_device *bdev, fmode_t mode,
6279 		    unsigned int cmd, unsigned long arg)
6280 {
6281 	switch (cmd) {
6282 	case HOT_REMOVE_DISK:
6283 	case HOT_ADD_DISK:
6284 	case SET_DISK_FAULTY:
6285 	case SET_BITMAP_FILE:
6286 		/* These take in integer arg, do not convert */
6287 		break;
6288 	default:
6289 		arg = (unsigned long)compat_ptr(arg);
6290 		break;
6291 	}
6292 
6293 	return md_ioctl(bdev, mode, cmd, arg);
6294 }
6295 #endif /* CONFIG_COMPAT */
6296 
6297 static int md_open(struct block_device *bdev, fmode_t mode)
6298 {
6299 	/*
6300 	 * Succeed if we can lock the mddev, which confirms that
6301 	 * it isn't being stopped right now.
6302 	 */
6303 	struct mddev *mddev = mddev_find(bdev->bd_dev);
6304 	int err;
6305 
6306 	if (mddev->gendisk != bdev->bd_disk) {
6307 		/* we are racing with mddev_put which is discarding this
6308 		 * bd_disk.
6309 		 */
6310 		mddev_put(mddev);
6311 		/* Wait until bdev->bd_disk is definitely gone */
6312 		flush_workqueue(md_misc_wq);
6313 		/* Then retry the open from the top */
6314 		return -ERESTARTSYS;
6315 	}
6316 	BUG_ON(mddev != bdev->bd_disk->private_data);
6317 
6318 	if ((err = mutex_lock_interruptible(&mddev->open_mutex)))
6319 		goto out;
6320 
6321 	err = 0;
6322 	atomic_inc(&mddev->openers);
6323 	mutex_unlock(&mddev->open_mutex);
6324 
6325 	check_disk_change(bdev);
6326  out:
6327 	return err;
6328 }
6329 
6330 static int md_release(struct gendisk *disk, fmode_t mode)
6331 {
6332  	struct mddev *mddev = disk->private_data;
6333 
6334 	BUG_ON(!mddev);
6335 	atomic_dec(&mddev->openers);
6336 	mddev_put(mddev);
6337 
6338 	return 0;
6339 }
6340 
6341 static int md_media_changed(struct gendisk *disk)
6342 {
6343 	struct mddev *mddev = disk->private_data;
6344 
6345 	return mddev->changed;
6346 }
6347 
6348 static int md_revalidate(struct gendisk *disk)
6349 {
6350 	struct mddev *mddev = disk->private_data;
6351 
6352 	mddev->changed = 0;
6353 	return 0;
6354 }
6355 static const struct block_device_operations md_fops =
6356 {
6357 	.owner		= THIS_MODULE,
6358 	.open		= md_open,
6359 	.release	= md_release,
6360 	.ioctl		= md_ioctl,
6361 #ifdef CONFIG_COMPAT
6362 	.compat_ioctl	= md_compat_ioctl,
6363 #endif
6364 	.getgeo		= md_getgeo,
6365 	.media_changed  = md_media_changed,
6366 	.revalidate_disk= md_revalidate,
6367 };
6368 
6369 static int md_thread(void * arg)
6370 {
6371 	struct md_thread *thread = arg;
6372 
6373 	/*
6374 	 * md_thread is a 'system-thread', it's priority should be very
6375 	 * high. We avoid resource deadlocks individually in each
6376 	 * raid personality. (RAID5 does preallocation) We also use RR and
6377 	 * the very same RT priority as kswapd, thus we will never get
6378 	 * into a priority inversion deadlock.
6379 	 *
6380 	 * we definitely have to have equal or higher priority than
6381 	 * bdflush, otherwise bdflush will deadlock if there are too
6382 	 * many dirty RAID5 blocks.
6383 	 */
6384 
6385 	allow_signal(SIGKILL);
6386 	while (!kthread_should_stop()) {
6387 
6388 		/* We need to wait INTERRUPTIBLE so that
6389 		 * we don't add to the load-average.
6390 		 * That means we need to be sure no signals are
6391 		 * pending
6392 		 */
6393 		if (signal_pending(current))
6394 			flush_signals(current);
6395 
6396 		wait_event_interruptible_timeout
6397 			(thread->wqueue,
6398 			 test_bit(THREAD_WAKEUP, &thread->flags)
6399 			 || kthread_should_stop(),
6400 			 thread->timeout);
6401 
6402 		clear_bit(THREAD_WAKEUP, &thread->flags);
6403 		if (!kthread_should_stop())
6404 			thread->run(thread->mddev);
6405 	}
6406 
6407 	return 0;
6408 }
6409 
6410 void md_wakeup_thread(struct md_thread *thread)
6411 {
6412 	if (thread) {
6413 		pr_debug("md: waking up MD thread %s.\n", thread->tsk->comm);
6414 		set_bit(THREAD_WAKEUP, &thread->flags);
6415 		wake_up(&thread->wqueue);
6416 	}
6417 }
6418 
6419 struct md_thread *md_register_thread(void (*run) (struct mddev *), struct mddev *mddev,
6420 				 const char *name)
6421 {
6422 	struct md_thread *thread;
6423 
6424 	thread = kzalloc(sizeof(struct md_thread), GFP_KERNEL);
6425 	if (!thread)
6426 		return NULL;
6427 
6428 	init_waitqueue_head(&thread->wqueue);
6429 
6430 	thread->run = run;
6431 	thread->mddev = mddev;
6432 	thread->timeout = MAX_SCHEDULE_TIMEOUT;
6433 	thread->tsk = kthread_run(md_thread, thread,
6434 				  "%s_%s",
6435 				  mdname(thread->mddev),
6436 				  name ?: mddev->pers->name);
6437 	if (IS_ERR(thread->tsk)) {
6438 		kfree(thread);
6439 		return NULL;
6440 	}
6441 	return thread;
6442 }
6443 
6444 void md_unregister_thread(struct md_thread **threadp)
6445 {
6446 	struct md_thread *thread = *threadp;
6447 	if (!thread)
6448 		return;
6449 	pr_debug("interrupting MD-thread pid %d\n", task_pid_nr(thread->tsk));
6450 	/* Locking ensures that mddev_unlock does not wake_up a
6451 	 * non-existent thread
6452 	 */
6453 	spin_lock(&pers_lock);
6454 	*threadp = NULL;
6455 	spin_unlock(&pers_lock);
6456 
6457 	kthread_stop(thread->tsk);
6458 	kfree(thread);
6459 }
6460 
6461 void md_error(struct mddev *mddev, struct md_rdev *rdev)
6462 {
6463 	if (!mddev) {
6464 		MD_BUG();
6465 		return;
6466 	}
6467 
6468 	if (!rdev || test_bit(Faulty, &rdev->flags))
6469 		return;
6470 
6471 	if (!mddev->pers || !mddev->pers->error_handler)
6472 		return;
6473 	mddev->pers->error_handler(mddev,rdev);
6474 	if (mddev->degraded)
6475 		set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
6476 	sysfs_notify_dirent_safe(rdev->sysfs_state);
6477 	set_bit(MD_RECOVERY_INTR, &mddev->recovery);
6478 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
6479 	md_wakeup_thread(mddev->thread);
6480 	if (mddev->event_work.func)
6481 		queue_work(md_misc_wq, &mddev->event_work);
6482 	md_new_event_inintr(mddev);
6483 }
6484 
6485 /* seq_file implementation /proc/mdstat */
6486 
6487 static void status_unused(struct seq_file *seq)
6488 {
6489 	int i = 0;
6490 	struct md_rdev *rdev;
6491 
6492 	seq_printf(seq, "unused devices: ");
6493 
6494 	list_for_each_entry(rdev, &pending_raid_disks, same_set) {
6495 		char b[BDEVNAME_SIZE];
6496 		i++;
6497 		seq_printf(seq, "%s ",
6498 			      bdevname(rdev->bdev,b));
6499 	}
6500 	if (!i)
6501 		seq_printf(seq, "<none>");
6502 
6503 	seq_printf(seq, "\n");
6504 }
6505 
6506 
6507 static void status_resync(struct seq_file *seq, struct mddev * mddev)
6508 {
6509 	sector_t max_sectors, resync, res;
6510 	unsigned long dt, db;
6511 	sector_t rt;
6512 	int scale;
6513 	unsigned int per_milli;
6514 
6515 	resync = mddev->curr_resync - atomic_read(&mddev->recovery_active);
6516 
6517 	if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery))
6518 		max_sectors = mddev->resync_max_sectors;
6519 	else
6520 		max_sectors = mddev->dev_sectors;
6521 
6522 	/*
6523 	 * Should not happen.
6524 	 */
6525 	if (!max_sectors) {
6526 		MD_BUG();
6527 		return;
6528 	}
6529 	/* Pick 'scale' such that (resync>>scale)*1000 will fit
6530 	 * in a sector_t, and (max_sectors>>scale) will fit in a
6531 	 * u32, as those are the requirements for sector_div.
6532 	 * Thus 'scale' must be at least 10
6533 	 */
6534 	scale = 10;
6535 	if (sizeof(sector_t) > sizeof(unsigned long)) {
6536 		while ( max_sectors/2 > (1ULL<<(scale+32)))
6537 			scale++;
6538 	}
6539 	res = (resync>>scale)*1000;
6540 	sector_div(res, (u32)((max_sectors>>scale)+1));
6541 
6542 	per_milli = res;
6543 	{
6544 		int i, x = per_milli/50, y = 20-x;
6545 		seq_printf(seq, "[");
6546 		for (i = 0; i < x; i++)
6547 			seq_printf(seq, "=");
6548 		seq_printf(seq, ">");
6549 		for (i = 0; i < y; i++)
6550 			seq_printf(seq, ".");
6551 		seq_printf(seq, "] ");
6552 	}
6553 	seq_printf(seq, " %s =%3u.%u%% (%llu/%llu)",
6554 		   (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)?
6555 		    "reshape" :
6556 		    (test_bit(MD_RECOVERY_CHECK, &mddev->recovery)?
6557 		     "check" :
6558 		     (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) ?
6559 		      "resync" : "recovery"))),
6560 		   per_milli/10, per_milli % 10,
6561 		   (unsigned long long) resync/2,
6562 		   (unsigned long long) max_sectors/2);
6563 
6564 	/*
6565 	 * dt: time from mark until now
6566 	 * db: blocks written from mark until now
6567 	 * rt: remaining time
6568 	 *
6569 	 * rt is a sector_t, so could be 32bit or 64bit.
6570 	 * So we divide before multiply in case it is 32bit and close
6571 	 * to the limit.
6572 	 * We scale the divisor (db) by 32 to avoid losing precision
6573 	 * near the end of resync when the number of remaining sectors
6574 	 * is close to 'db'.
6575 	 * We then divide rt by 32 after multiplying by db to compensate.
6576 	 * The '+1' avoids division by zero if db is very small.
6577 	 */
6578 	dt = ((jiffies - mddev->resync_mark) / HZ);
6579 	if (!dt) dt++;
6580 	db = (mddev->curr_mark_cnt - atomic_read(&mddev->recovery_active))
6581 		- mddev->resync_mark_cnt;
6582 
6583 	rt = max_sectors - resync;    /* number of remaining sectors */
6584 	sector_div(rt, db/32+1);
6585 	rt *= dt;
6586 	rt >>= 5;
6587 
6588 	seq_printf(seq, " finish=%lu.%lumin", (unsigned long)rt / 60,
6589 		   ((unsigned long)rt % 60)/6);
6590 
6591 	seq_printf(seq, " speed=%ldK/sec", db/2/dt);
6592 }
6593 
6594 static void *md_seq_start(struct seq_file *seq, loff_t *pos)
6595 {
6596 	struct list_head *tmp;
6597 	loff_t l = *pos;
6598 	struct mddev *mddev;
6599 
6600 	if (l >= 0x10000)
6601 		return NULL;
6602 	if (!l--)
6603 		/* header */
6604 		return (void*)1;
6605 
6606 	spin_lock(&all_mddevs_lock);
6607 	list_for_each(tmp,&all_mddevs)
6608 		if (!l--) {
6609 			mddev = list_entry(tmp, struct mddev, all_mddevs);
6610 			mddev_get(mddev);
6611 			spin_unlock(&all_mddevs_lock);
6612 			return mddev;
6613 		}
6614 	spin_unlock(&all_mddevs_lock);
6615 	if (!l--)
6616 		return (void*)2;/* tail */
6617 	return NULL;
6618 }
6619 
6620 static void *md_seq_next(struct seq_file *seq, void *v, loff_t *pos)
6621 {
6622 	struct list_head *tmp;
6623 	struct mddev *next_mddev, *mddev = v;
6624 
6625 	++*pos;
6626 	if (v == (void*)2)
6627 		return NULL;
6628 
6629 	spin_lock(&all_mddevs_lock);
6630 	if (v == (void*)1)
6631 		tmp = all_mddevs.next;
6632 	else
6633 		tmp = mddev->all_mddevs.next;
6634 	if (tmp != &all_mddevs)
6635 		next_mddev = mddev_get(list_entry(tmp,struct mddev,all_mddevs));
6636 	else {
6637 		next_mddev = (void*)2;
6638 		*pos = 0x10000;
6639 	}
6640 	spin_unlock(&all_mddevs_lock);
6641 
6642 	if (v != (void*)1)
6643 		mddev_put(mddev);
6644 	return next_mddev;
6645 
6646 }
6647 
6648 static void md_seq_stop(struct seq_file *seq, void *v)
6649 {
6650 	struct mddev *mddev = v;
6651 
6652 	if (mddev && v != (void*)1 && v != (void*)2)
6653 		mddev_put(mddev);
6654 }
6655 
6656 static int md_seq_show(struct seq_file *seq, void *v)
6657 {
6658 	struct mddev *mddev = v;
6659 	sector_t sectors;
6660 	struct md_rdev *rdev;
6661 	struct bitmap *bitmap;
6662 
6663 	if (v == (void*)1) {
6664 		struct md_personality *pers;
6665 		seq_printf(seq, "Personalities : ");
6666 		spin_lock(&pers_lock);
6667 		list_for_each_entry(pers, &pers_list, list)
6668 			seq_printf(seq, "[%s] ", pers->name);
6669 
6670 		spin_unlock(&pers_lock);
6671 		seq_printf(seq, "\n");
6672 		seq->poll_event = atomic_read(&md_event_count);
6673 		return 0;
6674 	}
6675 	if (v == (void*)2) {
6676 		status_unused(seq);
6677 		return 0;
6678 	}
6679 
6680 	if (mddev_lock(mddev) < 0)
6681 		return -EINTR;
6682 
6683 	if (mddev->pers || mddev->raid_disks || !list_empty(&mddev->disks)) {
6684 		seq_printf(seq, "%s : %sactive", mdname(mddev),
6685 						mddev->pers ? "" : "in");
6686 		if (mddev->pers) {
6687 			if (mddev->ro==1)
6688 				seq_printf(seq, " (read-only)");
6689 			if (mddev->ro==2)
6690 				seq_printf(seq, " (auto-read-only)");
6691 			seq_printf(seq, " %s", mddev->pers->name);
6692 		}
6693 
6694 		sectors = 0;
6695 		list_for_each_entry(rdev, &mddev->disks, same_set) {
6696 			char b[BDEVNAME_SIZE];
6697 			seq_printf(seq, " %s[%d]",
6698 				bdevname(rdev->bdev,b), rdev->desc_nr);
6699 			if (test_bit(WriteMostly, &rdev->flags))
6700 				seq_printf(seq, "(W)");
6701 			if (test_bit(Faulty, &rdev->flags)) {
6702 				seq_printf(seq, "(F)");
6703 				continue;
6704 			} else if (rdev->raid_disk < 0)
6705 				seq_printf(seq, "(S)"); /* spare */
6706 			sectors += rdev->sectors;
6707 		}
6708 
6709 		if (!list_empty(&mddev->disks)) {
6710 			if (mddev->pers)
6711 				seq_printf(seq, "\n      %llu blocks",
6712 					   (unsigned long long)
6713 					   mddev->array_sectors / 2);
6714 			else
6715 				seq_printf(seq, "\n      %llu blocks",
6716 					   (unsigned long long)sectors / 2);
6717 		}
6718 		if (mddev->persistent) {
6719 			if (mddev->major_version != 0 ||
6720 			    mddev->minor_version != 90) {
6721 				seq_printf(seq," super %d.%d",
6722 					   mddev->major_version,
6723 					   mddev->minor_version);
6724 			}
6725 		} else if (mddev->external)
6726 			seq_printf(seq, " super external:%s",
6727 				   mddev->metadata_type);
6728 		else
6729 			seq_printf(seq, " super non-persistent");
6730 
6731 		if (mddev->pers) {
6732 			mddev->pers->status(seq, mddev);
6733 	 		seq_printf(seq, "\n      ");
6734 			if (mddev->pers->sync_request) {
6735 				if (mddev->curr_resync > 2) {
6736 					status_resync(seq, mddev);
6737 					seq_printf(seq, "\n      ");
6738 				} else if (mddev->curr_resync == 1 || mddev->curr_resync == 2)
6739 					seq_printf(seq, "\tresync=DELAYED\n      ");
6740 				else if (mddev->recovery_cp < MaxSector)
6741 					seq_printf(seq, "\tresync=PENDING\n      ");
6742 			}
6743 		} else
6744 			seq_printf(seq, "\n       ");
6745 
6746 		if ((bitmap = mddev->bitmap)) {
6747 			unsigned long chunk_kb;
6748 			unsigned long flags;
6749 			spin_lock_irqsave(&bitmap->lock, flags);
6750 			chunk_kb = mddev->bitmap_info.chunksize >> 10;
6751 			seq_printf(seq, "bitmap: %lu/%lu pages [%luKB], "
6752 				"%lu%s chunk",
6753 				bitmap->pages - bitmap->missing_pages,
6754 				bitmap->pages,
6755 				(bitmap->pages - bitmap->missing_pages)
6756 					<< (PAGE_SHIFT - 10),
6757 				chunk_kb ? chunk_kb : mddev->bitmap_info.chunksize,
6758 				chunk_kb ? "KB" : "B");
6759 			if (bitmap->file) {
6760 				seq_printf(seq, ", file: ");
6761 				seq_path(seq, &bitmap->file->f_path, " \t\n");
6762 			}
6763 
6764 			seq_printf(seq, "\n");
6765 			spin_unlock_irqrestore(&bitmap->lock, flags);
6766 		}
6767 
6768 		seq_printf(seq, "\n");
6769 	}
6770 	mddev_unlock(mddev);
6771 
6772 	return 0;
6773 }
6774 
6775 static const struct seq_operations md_seq_ops = {
6776 	.start  = md_seq_start,
6777 	.next   = md_seq_next,
6778 	.stop   = md_seq_stop,
6779 	.show   = md_seq_show,
6780 };
6781 
6782 static int md_seq_open(struct inode *inode, struct file *file)
6783 {
6784 	struct seq_file *seq;
6785 	int error;
6786 
6787 	error = seq_open(file, &md_seq_ops);
6788 	if (error)
6789 		return error;
6790 
6791 	seq = file->private_data;
6792 	seq->poll_event = atomic_read(&md_event_count);
6793 	return error;
6794 }
6795 
6796 static unsigned int mdstat_poll(struct file *filp, poll_table *wait)
6797 {
6798 	struct seq_file *seq = filp->private_data;
6799 	int mask;
6800 
6801 	poll_wait(filp, &md_event_waiters, wait);
6802 
6803 	/* always allow read */
6804 	mask = POLLIN | POLLRDNORM;
6805 
6806 	if (seq->poll_event != atomic_read(&md_event_count))
6807 		mask |= POLLERR | POLLPRI;
6808 	return mask;
6809 }
6810 
6811 static const struct file_operations md_seq_fops = {
6812 	.owner		= THIS_MODULE,
6813 	.open           = md_seq_open,
6814 	.read           = seq_read,
6815 	.llseek         = seq_lseek,
6816 	.release	= seq_release_private,
6817 	.poll		= mdstat_poll,
6818 };
6819 
6820 int register_md_personality(struct md_personality *p)
6821 {
6822 	spin_lock(&pers_lock);
6823 	list_add_tail(&p->list, &pers_list);
6824 	printk(KERN_INFO "md: %s personality registered for level %d\n", p->name, p->level);
6825 	spin_unlock(&pers_lock);
6826 	return 0;
6827 }
6828 
6829 int unregister_md_personality(struct md_personality *p)
6830 {
6831 	printk(KERN_INFO "md: %s personality unregistered\n", p->name);
6832 	spin_lock(&pers_lock);
6833 	list_del_init(&p->list);
6834 	spin_unlock(&pers_lock);
6835 	return 0;
6836 }
6837 
6838 static int is_mddev_idle(struct mddev *mddev, int init)
6839 {
6840 	struct md_rdev * rdev;
6841 	int idle;
6842 	int curr_events;
6843 
6844 	idle = 1;
6845 	rcu_read_lock();
6846 	rdev_for_each_rcu(rdev, mddev) {
6847 		struct gendisk *disk = rdev->bdev->bd_contains->bd_disk;
6848 		curr_events = (int)part_stat_read(&disk->part0, sectors[0]) +
6849 			      (int)part_stat_read(&disk->part0, sectors[1]) -
6850 			      atomic_read(&disk->sync_io);
6851 		/* sync IO will cause sync_io to increase before the disk_stats
6852 		 * as sync_io is counted when a request starts, and
6853 		 * disk_stats is counted when it completes.
6854 		 * So resync activity will cause curr_events to be smaller than
6855 		 * when there was no such activity.
6856 		 * non-sync IO will cause disk_stat to increase without
6857 		 * increasing sync_io so curr_events will (eventually)
6858 		 * be larger than it was before.  Once it becomes
6859 		 * substantially larger, the test below will cause
6860 		 * the array to appear non-idle, and resync will slow
6861 		 * down.
6862 		 * If there is a lot of outstanding resync activity when
6863 		 * we set last_event to curr_events, then all that activity
6864 		 * completing might cause the array to appear non-idle
6865 		 * and resync will be slowed down even though there might
6866 		 * not have been non-resync activity.  This will only
6867 		 * happen once though.  'last_events' will soon reflect
6868 		 * the state where there is little or no outstanding
6869 		 * resync requests, and further resync activity will
6870 		 * always make curr_events less than last_events.
6871 		 *
6872 		 */
6873 		if (init || curr_events - rdev->last_events > 64) {
6874 			rdev->last_events = curr_events;
6875 			idle = 0;
6876 		}
6877 	}
6878 	rcu_read_unlock();
6879 	return idle;
6880 }
6881 
6882 void md_done_sync(struct mddev *mddev, int blocks, int ok)
6883 {
6884 	/* another "blocks" (512byte) blocks have been synced */
6885 	atomic_sub(blocks, &mddev->recovery_active);
6886 	wake_up(&mddev->recovery_wait);
6887 	if (!ok) {
6888 		set_bit(MD_RECOVERY_INTR, &mddev->recovery);
6889 		md_wakeup_thread(mddev->thread);
6890 		// stop recovery, signal do_sync ....
6891 	}
6892 }
6893 
6894 
6895 /* md_write_start(mddev, bi)
6896  * If we need to update some array metadata (e.g. 'active' flag
6897  * in superblock) before writing, schedule a superblock update
6898  * and wait for it to complete.
6899  */
6900 void md_write_start(struct mddev *mddev, struct bio *bi)
6901 {
6902 	int did_change = 0;
6903 	if (bio_data_dir(bi) != WRITE)
6904 		return;
6905 
6906 	BUG_ON(mddev->ro == 1);
6907 	if (mddev->ro == 2) {
6908 		/* need to switch to read/write */
6909 		mddev->ro = 0;
6910 		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
6911 		md_wakeup_thread(mddev->thread);
6912 		md_wakeup_thread(mddev->sync_thread);
6913 		did_change = 1;
6914 	}
6915 	atomic_inc(&mddev->writes_pending);
6916 	if (mddev->safemode == 1)
6917 		mddev->safemode = 0;
6918 	if (mddev->in_sync) {
6919 		spin_lock_irq(&mddev->write_lock);
6920 		if (mddev->in_sync) {
6921 			mddev->in_sync = 0;
6922 			set_bit(MD_CHANGE_CLEAN, &mddev->flags);
6923 			set_bit(MD_CHANGE_PENDING, &mddev->flags);
6924 			md_wakeup_thread(mddev->thread);
6925 			did_change = 1;
6926 		}
6927 		spin_unlock_irq(&mddev->write_lock);
6928 	}
6929 	if (did_change)
6930 		sysfs_notify_dirent_safe(mddev->sysfs_state);
6931 	wait_event(mddev->sb_wait,
6932 		   !test_bit(MD_CHANGE_PENDING, &mddev->flags));
6933 }
6934 
6935 void md_write_end(struct mddev *mddev)
6936 {
6937 	if (atomic_dec_and_test(&mddev->writes_pending)) {
6938 		if (mddev->safemode == 2)
6939 			md_wakeup_thread(mddev->thread);
6940 		else if (mddev->safemode_delay)
6941 			mod_timer(&mddev->safemode_timer, jiffies + mddev->safemode_delay);
6942 	}
6943 }
6944 
6945 /* md_allow_write(mddev)
6946  * Calling this ensures that the array is marked 'active' so that writes
6947  * may proceed without blocking.  It is important to call this before
6948  * attempting a GFP_KERNEL allocation while holding the mddev lock.
6949  * Must be called with mddev_lock held.
6950  *
6951  * In the ->external case MD_CHANGE_CLEAN can not be cleared until mddev->lock
6952  * is dropped, so return -EAGAIN after notifying userspace.
6953  */
6954 int md_allow_write(struct mddev *mddev)
6955 {
6956 	if (!mddev->pers)
6957 		return 0;
6958 	if (mddev->ro)
6959 		return 0;
6960 	if (!mddev->pers->sync_request)
6961 		return 0;
6962 
6963 	spin_lock_irq(&mddev->write_lock);
6964 	if (mddev->in_sync) {
6965 		mddev->in_sync = 0;
6966 		set_bit(MD_CHANGE_CLEAN, &mddev->flags);
6967 		set_bit(MD_CHANGE_PENDING, &mddev->flags);
6968 		if (mddev->safemode_delay &&
6969 		    mddev->safemode == 0)
6970 			mddev->safemode = 1;
6971 		spin_unlock_irq(&mddev->write_lock);
6972 		md_update_sb(mddev, 0);
6973 		sysfs_notify_dirent_safe(mddev->sysfs_state);
6974 	} else
6975 		spin_unlock_irq(&mddev->write_lock);
6976 
6977 	if (test_bit(MD_CHANGE_PENDING, &mddev->flags))
6978 		return -EAGAIN;
6979 	else
6980 		return 0;
6981 }
6982 EXPORT_SYMBOL_GPL(md_allow_write);
6983 
6984 #define SYNC_MARKS	10
6985 #define	SYNC_MARK_STEP	(3*HZ)
6986 void md_do_sync(struct mddev *mddev)
6987 {
6988 	struct mddev *mddev2;
6989 	unsigned int currspeed = 0,
6990 		 window;
6991 	sector_t max_sectors,j, io_sectors;
6992 	unsigned long mark[SYNC_MARKS];
6993 	sector_t mark_cnt[SYNC_MARKS];
6994 	int last_mark,m;
6995 	struct list_head *tmp;
6996 	sector_t last_check;
6997 	int skipped = 0;
6998 	struct md_rdev *rdev;
6999 	char *desc;
7000 
7001 	/* just incase thread restarts... */
7002 	if (test_bit(MD_RECOVERY_DONE, &mddev->recovery))
7003 		return;
7004 	if (mddev->ro) /* never try to sync a read-only array */
7005 		return;
7006 
7007 	if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
7008 		if (test_bit(MD_RECOVERY_CHECK, &mddev->recovery))
7009 			desc = "data-check";
7010 		else if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
7011 			desc = "requested-resync";
7012 		else
7013 			desc = "resync";
7014 	} else if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
7015 		desc = "reshape";
7016 	else
7017 		desc = "recovery";
7018 
7019 	/* we overload curr_resync somewhat here.
7020 	 * 0 == not engaged in resync at all
7021 	 * 2 == checking that there is no conflict with another sync
7022 	 * 1 == like 2, but have yielded to allow conflicting resync to
7023 	 *		commense
7024 	 * other == active in resync - this many blocks
7025 	 *
7026 	 * Before starting a resync we must have set curr_resync to
7027 	 * 2, and then checked that every "conflicting" array has curr_resync
7028 	 * less than ours.  When we find one that is the same or higher
7029 	 * we wait on resync_wait.  To avoid deadlock, we reduce curr_resync
7030 	 * to 1 if we choose to yield (based arbitrarily on address of mddev structure).
7031 	 * This will mean we have to start checking from the beginning again.
7032 	 *
7033 	 */
7034 
7035 	do {
7036 		mddev->curr_resync = 2;
7037 
7038 	try_again:
7039 		if (kthread_should_stop())
7040 			set_bit(MD_RECOVERY_INTR, &mddev->recovery);
7041 
7042 		if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
7043 			goto skip;
7044 		for_each_mddev(mddev2, tmp) {
7045 			if (mddev2 == mddev)
7046 				continue;
7047 			if (!mddev->parallel_resync
7048 			&&  mddev2->curr_resync
7049 			&&  match_mddev_units(mddev, mddev2)) {
7050 				DEFINE_WAIT(wq);
7051 				if (mddev < mddev2 && mddev->curr_resync == 2) {
7052 					/* arbitrarily yield */
7053 					mddev->curr_resync = 1;
7054 					wake_up(&resync_wait);
7055 				}
7056 				if (mddev > mddev2 && mddev->curr_resync == 1)
7057 					/* no need to wait here, we can wait the next
7058 					 * time 'round when curr_resync == 2
7059 					 */
7060 					continue;
7061 				/* We need to wait 'interruptible' so as not to
7062 				 * contribute to the load average, and not to
7063 				 * be caught by 'softlockup'
7064 				 */
7065 				prepare_to_wait(&resync_wait, &wq, TASK_INTERRUPTIBLE);
7066 				if (!kthread_should_stop() &&
7067 				    mddev2->curr_resync >= mddev->curr_resync) {
7068 					printk(KERN_INFO "md: delaying %s of %s"
7069 					       " until %s has finished (they"
7070 					       " share one or more physical units)\n",
7071 					       desc, mdname(mddev), mdname(mddev2));
7072 					mddev_put(mddev2);
7073 					if (signal_pending(current))
7074 						flush_signals(current);
7075 					schedule();
7076 					finish_wait(&resync_wait, &wq);
7077 					goto try_again;
7078 				}
7079 				finish_wait(&resync_wait, &wq);
7080 			}
7081 		}
7082 	} while (mddev->curr_resync < 2);
7083 
7084 	j = 0;
7085 	if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
7086 		/* resync follows the size requested by the personality,
7087 		 * which defaults to physical size, but can be virtual size
7088 		 */
7089 		max_sectors = mddev->resync_max_sectors;
7090 		mddev->resync_mismatches = 0;
7091 		/* we don't use the checkpoint if there's a bitmap */
7092 		if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
7093 			j = mddev->resync_min;
7094 		else if (!mddev->bitmap)
7095 			j = mddev->recovery_cp;
7096 
7097 	} else if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
7098 		max_sectors = mddev->dev_sectors;
7099 	else {
7100 		/* recovery follows the physical size of devices */
7101 		max_sectors = mddev->dev_sectors;
7102 		j = MaxSector;
7103 		rcu_read_lock();
7104 		list_for_each_entry_rcu(rdev, &mddev->disks, same_set)
7105 			if (rdev->raid_disk >= 0 &&
7106 			    !test_bit(Faulty, &rdev->flags) &&
7107 			    !test_bit(In_sync, &rdev->flags) &&
7108 			    rdev->recovery_offset < j)
7109 				j = rdev->recovery_offset;
7110 		rcu_read_unlock();
7111 	}
7112 
7113 	printk(KERN_INFO "md: %s of RAID array %s\n", desc, mdname(mddev));
7114 	printk(KERN_INFO "md: minimum _guaranteed_  speed:"
7115 		" %d KB/sec/disk.\n", speed_min(mddev));
7116 	printk(KERN_INFO "md: using maximum available idle IO bandwidth "
7117 	       "(but not more than %d KB/sec) for %s.\n",
7118 	       speed_max(mddev), desc);
7119 
7120 	is_mddev_idle(mddev, 1); /* this initializes IO event counters */
7121 
7122 	io_sectors = 0;
7123 	for (m = 0; m < SYNC_MARKS; m++) {
7124 		mark[m] = jiffies;
7125 		mark_cnt[m] = io_sectors;
7126 	}
7127 	last_mark = 0;
7128 	mddev->resync_mark = mark[last_mark];
7129 	mddev->resync_mark_cnt = mark_cnt[last_mark];
7130 
7131 	/*
7132 	 * Tune reconstruction:
7133 	 */
7134 	window = 32*(PAGE_SIZE/512);
7135 	printk(KERN_INFO "md: using %dk window, over a total of %lluk.\n",
7136 		window/2, (unsigned long long)max_sectors/2);
7137 
7138 	atomic_set(&mddev->recovery_active, 0);
7139 	last_check = 0;
7140 
7141 	if (j>2) {
7142 		printk(KERN_INFO
7143 		       "md: resuming %s of %s from checkpoint.\n",
7144 		       desc, mdname(mddev));
7145 		mddev->curr_resync = j;
7146 	}
7147 	mddev->curr_resync_completed = j;
7148 
7149 	while (j < max_sectors) {
7150 		sector_t sectors;
7151 
7152 		skipped = 0;
7153 
7154 		if (!test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
7155 		    ((mddev->curr_resync > mddev->curr_resync_completed &&
7156 		      (mddev->curr_resync - mddev->curr_resync_completed)
7157 		      > (max_sectors >> 4)) ||
7158 		     (j - mddev->curr_resync_completed)*2
7159 		     >= mddev->resync_max - mddev->curr_resync_completed
7160 			    )) {
7161 			/* time to update curr_resync_completed */
7162 			wait_event(mddev->recovery_wait,
7163 				   atomic_read(&mddev->recovery_active) == 0);
7164 			mddev->curr_resync_completed = j;
7165 			set_bit(MD_CHANGE_CLEAN, &mddev->flags);
7166 			sysfs_notify(&mddev->kobj, NULL, "sync_completed");
7167 		}
7168 
7169 		while (j >= mddev->resync_max && !kthread_should_stop()) {
7170 			/* As this condition is controlled by user-space,
7171 			 * we can block indefinitely, so use '_interruptible'
7172 			 * to avoid triggering warnings.
7173 			 */
7174 			flush_signals(current); /* just in case */
7175 			wait_event_interruptible(mddev->recovery_wait,
7176 						 mddev->resync_max > j
7177 						 || kthread_should_stop());
7178 		}
7179 
7180 		if (kthread_should_stop())
7181 			goto interrupted;
7182 
7183 		sectors = mddev->pers->sync_request(mddev, j, &skipped,
7184 						  currspeed < speed_min(mddev));
7185 		if (sectors == 0) {
7186 			set_bit(MD_RECOVERY_INTR, &mddev->recovery);
7187 			goto out;
7188 		}
7189 
7190 		if (!skipped) { /* actual IO requested */
7191 			io_sectors += sectors;
7192 			atomic_add(sectors, &mddev->recovery_active);
7193 		}
7194 
7195 		if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
7196 			break;
7197 
7198 		j += sectors;
7199 		if (j>1) mddev->curr_resync = j;
7200 		mddev->curr_mark_cnt = io_sectors;
7201 		if (last_check == 0)
7202 			/* this is the earliest that rebuild will be
7203 			 * visible in /proc/mdstat
7204 			 */
7205 			md_new_event(mddev);
7206 
7207 		if (last_check + window > io_sectors || j == max_sectors)
7208 			continue;
7209 
7210 		last_check = io_sectors;
7211 	repeat:
7212 		if (time_after_eq(jiffies, mark[last_mark] + SYNC_MARK_STEP )) {
7213 			/* step marks */
7214 			int next = (last_mark+1) % SYNC_MARKS;
7215 
7216 			mddev->resync_mark = mark[next];
7217 			mddev->resync_mark_cnt = mark_cnt[next];
7218 			mark[next] = jiffies;
7219 			mark_cnt[next] = io_sectors - atomic_read(&mddev->recovery_active);
7220 			last_mark = next;
7221 		}
7222 
7223 
7224 		if (kthread_should_stop())
7225 			goto interrupted;
7226 
7227 
7228 		/*
7229 		 * this loop exits only if either when we are slower than
7230 		 * the 'hard' speed limit, or the system was IO-idle for
7231 		 * a jiffy.
7232 		 * the system might be non-idle CPU-wise, but we only care
7233 		 * about not overloading the IO subsystem. (things like an
7234 		 * e2fsck being done on the RAID array should execute fast)
7235 		 */
7236 		cond_resched();
7237 
7238 		currspeed = ((unsigned long)(io_sectors-mddev->resync_mark_cnt))/2
7239 			/((jiffies-mddev->resync_mark)/HZ +1) +1;
7240 
7241 		if (currspeed > speed_min(mddev)) {
7242 			if ((currspeed > speed_max(mddev)) ||
7243 					!is_mddev_idle(mddev, 0)) {
7244 				msleep(500);
7245 				goto repeat;
7246 			}
7247 		}
7248 	}
7249 	printk(KERN_INFO "md: %s: %s done.\n",mdname(mddev), desc);
7250 	/*
7251 	 * this also signals 'finished resyncing' to md_stop
7252 	 */
7253  out:
7254 	wait_event(mddev->recovery_wait, !atomic_read(&mddev->recovery_active));
7255 
7256 	/* tell personality that we are finished */
7257 	mddev->pers->sync_request(mddev, max_sectors, &skipped, 1);
7258 
7259 	if (!test_bit(MD_RECOVERY_CHECK, &mddev->recovery) &&
7260 	    mddev->curr_resync > 2) {
7261 		if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
7262 			if (test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
7263 				if (mddev->curr_resync >= mddev->recovery_cp) {
7264 					printk(KERN_INFO
7265 					       "md: checkpointing %s of %s.\n",
7266 					       desc, mdname(mddev));
7267 					mddev->recovery_cp = mddev->curr_resync;
7268 				}
7269 			} else
7270 				mddev->recovery_cp = MaxSector;
7271 		} else {
7272 			if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery))
7273 				mddev->curr_resync = MaxSector;
7274 			rcu_read_lock();
7275 			list_for_each_entry_rcu(rdev, &mddev->disks, same_set)
7276 				if (rdev->raid_disk >= 0 &&
7277 				    mddev->delta_disks >= 0 &&
7278 				    !test_bit(Faulty, &rdev->flags) &&
7279 				    !test_bit(In_sync, &rdev->flags) &&
7280 				    rdev->recovery_offset < mddev->curr_resync)
7281 					rdev->recovery_offset = mddev->curr_resync;
7282 			rcu_read_unlock();
7283 		}
7284 	}
7285 	set_bit(MD_CHANGE_DEVS, &mddev->flags);
7286 
7287  skip:
7288 	if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
7289 		/* We completed so min/max setting can be forgotten if used. */
7290 		if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
7291 			mddev->resync_min = 0;
7292 		mddev->resync_max = MaxSector;
7293 	} else if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
7294 		mddev->resync_min = mddev->curr_resync_completed;
7295 	mddev->curr_resync = 0;
7296 	wake_up(&resync_wait);
7297 	set_bit(MD_RECOVERY_DONE, &mddev->recovery);
7298 	md_wakeup_thread(mddev->thread);
7299 	return;
7300 
7301  interrupted:
7302 	/*
7303 	 * got a signal, exit.
7304 	 */
7305 	printk(KERN_INFO
7306 	       "md: md_do_sync() got signal ... exiting\n");
7307 	set_bit(MD_RECOVERY_INTR, &mddev->recovery);
7308 	goto out;
7309 
7310 }
7311 EXPORT_SYMBOL_GPL(md_do_sync);
7312 
7313 static int remove_and_add_spares(struct mddev *mddev)
7314 {
7315 	struct md_rdev *rdev;
7316 	int spares = 0;
7317 
7318 	mddev->curr_resync_completed = 0;
7319 
7320 	list_for_each_entry(rdev, &mddev->disks, same_set)
7321 		if (rdev->raid_disk >= 0 &&
7322 		    !test_bit(Blocked, &rdev->flags) &&
7323 		    (test_bit(Faulty, &rdev->flags) ||
7324 		     ! test_bit(In_sync, &rdev->flags)) &&
7325 		    atomic_read(&rdev->nr_pending)==0) {
7326 			if (mddev->pers->hot_remove_disk(
7327 				    mddev, rdev->raid_disk)==0) {
7328 				sysfs_unlink_rdev(mddev, rdev);
7329 				rdev->raid_disk = -1;
7330 			}
7331 		}
7332 
7333 	if (mddev->degraded) {
7334 		list_for_each_entry(rdev, &mddev->disks, same_set) {
7335 			if (rdev->raid_disk >= 0 &&
7336 			    !test_bit(In_sync, &rdev->flags) &&
7337 			    !test_bit(Faulty, &rdev->flags))
7338 				spares++;
7339 			if (rdev->raid_disk < 0
7340 			    && !test_bit(Faulty, &rdev->flags)) {
7341 				rdev->recovery_offset = 0;
7342 				if (mddev->pers->
7343 				    hot_add_disk(mddev, rdev) == 0) {
7344 					if (sysfs_link_rdev(mddev, rdev))
7345 						/* failure here is OK */;
7346 					spares++;
7347 					md_new_event(mddev);
7348 					set_bit(MD_CHANGE_DEVS, &mddev->flags);
7349 				} else
7350 					break;
7351 			}
7352 		}
7353 	}
7354 	return spares;
7355 }
7356 
7357 static void reap_sync_thread(struct mddev *mddev)
7358 {
7359 	struct md_rdev *rdev;
7360 
7361 	/* resync has finished, collect result */
7362 	md_unregister_thread(&mddev->sync_thread);
7363 	if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery) &&
7364 	    !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
7365 		/* success...*/
7366 		/* activate any spares */
7367 		if (mddev->pers->spare_active(mddev))
7368 			sysfs_notify(&mddev->kobj, NULL,
7369 				     "degraded");
7370 	}
7371 	if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
7372 	    mddev->pers->finish_reshape)
7373 		mddev->pers->finish_reshape(mddev);
7374 
7375 	/* If array is no-longer degraded, then any saved_raid_disk
7376 	 * information must be scrapped.  Also if any device is now
7377 	 * In_sync we must scrape the saved_raid_disk for that device
7378 	 * do the superblock for an incrementally recovered device
7379 	 * written out.
7380 	 */
7381 	list_for_each_entry(rdev, &mddev->disks, same_set)
7382 		if (!mddev->degraded ||
7383 		    test_bit(In_sync, &rdev->flags))
7384 			rdev->saved_raid_disk = -1;
7385 
7386 	md_update_sb(mddev, 1);
7387 	clear_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
7388 	clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
7389 	clear_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
7390 	clear_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
7391 	clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
7392 	/* flag recovery needed just to double check */
7393 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
7394 	sysfs_notify_dirent_safe(mddev->sysfs_action);
7395 	md_new_event(mddev);
7396 	if (mddev->event_work.func)
7397 		queue_work(md_misc_wq, &mddev->event_work);
7398 }
7399 
7400 /*
7401  * This routine is regularly called by all per-raid-array threads to
7402  * deal with generic issues like resync and super-block update.
7403  * Raid personalities that don't have a thread (linear/raid0) do not
7404  * need this as they never do any recovery or update the superblock.
7405  *
7406  * It does not do any resync itself, but rather "forks" off other threads
7407  * to do that as needed.
7408  * When it is determined that resync is needed, we set MD_RECOVERY_RUNNING in
7409  * "->recovery" and create a thread at ->sync_thread.
7410  * When the thread finishes it sets MD_RECOVERY_DONE
7411  * and wakeups up this thread which will reap the thread and finish up.
7412  * This thread also removes any faulty devices (with nr_pending == 0).
7413  *
7414  * The overall approach is:
7415  *  1/ if the superblock needs updating, update it.
7416  *  2/ If a recovery thread is running, don't do anything else.
7417  *  3/ If recovery has finished, clean up, possibly marking spares active.
7418  *  4/ If there are any faulty devices, remove them.
7419  *  5/ If array is degraded, try to add spares devices
7420  *  6/ If array has spares or is not in-sync, start a resync thread.
7421  */
7422 void md_check_recovery(struct mddev *mddev)
7423 {
7424 	if (mddev->suspended)
7425 		return;
7426 
7427 	if (mddev->bitmap)
7428 		bitmap_daemon_work(mddev);
7429 
7430 	if (signal_pending(current)) {
7431 		if (mddev->pers->sync_request && !mddev->external) {
7432 			printk(KERN_INFO "md: %s in immediate safe mode\n",
7433 			       mdname(mddev));
7434 			mddev->safemode = 2;
7435 		}
7436 		flush_signals(current);
7437 	}
7438 
7439 	if (mddev->ro && !test_bit(MD_RECOVERY_NEEDED, &mddev->recovery))
7440 		return;
7441 	if ( ! (
7442 		(mddev->flags & ~ (1<<MD_CHANGE_PENDING)) ||
7443 		test_bit(MD_RECOVERY_NEEDED, &mddev->recovery) ||
7444 		test_bit(MD_RECOVERY_DONE, &mddev->recovery) ||
7445 		(mddev->external == 0 && mddev->safemode == 1) ||
7446 		(mddev->safemode == 2 && ! atomic_read(&mddev->writes_pending)
7447 		 && !mddev->in_sync && mddev->recovery_cp == MaxSector)
7448 		))
7449 		return;
7450 
7451 	if (mddev_trylock(mddev)) {
7452 		int spares = 0;
7453 
7454 		if (mddev->ro) {
7455 			/* Only thing we do on a ro array is remove
7456 			 * failed devices.
7457 			 */
7458 			struct md_rdev *rdev;
7459 			list_for_each_entry(rdev, &mddev->disks, same_set)
7460 				if (rdev->raid_disk >= 0 &&
7461 				    !test_bit(Blocked, &rdev->flags) &&
7462 				    test_bit(Faulty, &rdev->flags) &&
7463 				    atomic_read(&rdev->nr_pending)==0) {
7464 					if (mddev->pers->hot_remove_disk(
7465 						    mddev, rdev->raid_disk)==0) {
7466 						sysfs_unlink_rdev(mddev, rdev);
7467 						rdev->raid_disk = -1;
7468 					}
7469 				}
7470 			clear_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
7471 			goto unlock;
7472 		}
7473 
7474 		if (!mddev->external) {
7475 			int did_change = 0;
7476 			spin_lock_irq(&mddev->write_lock);
7477 			if (mddev->safemode &&
7478 			    !atomic_read(&mddev->writes_pending) &&
7479 			    !mddev->in_sync &&
7480 			    mddev->recovery_cp == MaxSector) {
7481 				mddev->in_sync = 1;
7482 				did_change = 1;
7483 				set_bit(MD_CHANGE_CLEAN, &mddev->flags);
7484 			}
7485 			if (mddev->safemode == 1)
7486 				mddev->safemode = 0;
7487 			spin_unlock_irq(&mddev->write_lock);
7488 			if (did_change)
7489 				sysfs_notify_dirent_safe(mddev->sysfs_state);
7490 		}
7491 
7492 		if (mddev->flags)
7493 			md_update_sb(mddev, 0);
7494 
7495 		if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) &&
7496 		    !test_bit(MD_RECOVERY_DONE, &mddev->recovery)) {
7497 			/* resync/recovery still happening */
7498 			clear_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
7499 			goto unlock;
7500 		}
7501 		if (mddev->sync_thread) {
7502 			reap_sync_thread(mddev);
7503 			goto unlock;
7504 		}
7505 		/* Set RUNNING before clearing NEEDED to avoid
7506 		 * any transients in the value of "sync_action".
7507 		 */
7508 		set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
7509 		clear_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
7510 		/* Clear some bits that don't mean anything, but
7511 		 * might be left set
7512 		 */
7513 		clear_bit(MD_RECOVERY_INTR, &mddev->recovery);
7514 		clear_bit(MD_RECOVERY_DONE, &mddev->recovery);
7515 
7516 		if (test_bit(MD_RECOVERY_FROZEN, &mddev->recovery))
7517 			goto unlock;
7518 		/* no recovery is running.
7519 		 * remove any failed drives, then
7520 		 * add spares if possible.
7521 		 * Spare are also removed and re-added, to allow
7522 		 * the personality to fail the re-add.
7523 		 */
7524 
7525 		if (mddev->reshape_position != MaxSector) {
7526 			if (mddev->pers->check_reshape == NULL ||
7527 			    mddev->pers->check_reshape(mddev) != 0)
7528 				/* Cannot proceed */
7529 				goto unlock;
7530 			set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
7531 			clear_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
7532 		} else if ((spares = remove_and_add_spares(mddev))) {
7533 			clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
7534 			clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
7535 			clear_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
7536 			set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
7537 		} else if (mddev->recovery_cp < MaxSector) {
7538 			set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
7539 			clear_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
7540 		} else if (!test_bit(MD_RECOVERY_SYNC, &mddev->recovery))
7541 			/* nothing to be done ... */
7542 			goto unlock;
7543 
7544 		if (mddev->pers->sync_request) {
7545 			if (spares && mddev->bitmap && ! mddev->bitmap->file) {
7546 				/* We are adding a device or devices to an array
7547 				 * which has the bitmap stored on all devices.
7548 				 * So make sure all bitmap pages get written
7549 				 */
7550 				bitmap_write_all(mddev->bitmap);
7551 			}
7552 			mddev->sync_thread = md_register_thread(md_do_sync,
7553 								mddev,
7554 								"resync");
7555 			if (!mddev->sync_thread) {
7556 				printk(KERN_ERR "%s: could not start resync"
7557 					" thread...\n",
7558 					mdname(mddev));
7559 				/* leave the spares where they are, it shouldn't hurt */
7560 				clear_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
7561 				clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
7562 				clear_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
7563 				clear_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
7564 				clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
7565 			} else
7566 				md_wakeup_thread(mddev->sync_thread);
7567 			sysfs_notify_dirent_safe(mddev->sysfs_action);
7568 			md_new_event(mddev);
7569 		}
7570 	unlock:
7571 		if (!mddev->sync_thread) {
7572 			clear_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
7573 			if (test_and_clear_bit(MD_RECOVERY_RECOVER,
7574 					       &mddev->recovery))
7575 				if (mddev->sysfs_action)
7576 					sysfs_notify_dirent_safe(mddev->sysfs_action);
7577 		}
7578 		mddev_unlock(mddev);
7579 	}
7580 }
7581 
7582 void md_wait_for_blocked_rdev(struct md_rdev *rdev, struct mddev *mddev)
7583 {
7584 	sysfs_notify_dirent_safe(rdev->sysfs_state);
7585 	wait_event_timeout(rdev->blocked_wait,
7586 			   !test_bit(Blocked, &rdev->flags) &&
7587 			   !test_bit(BlockedBadBlocks, &rdev->flags),
7588 			   msecs_to_jiffies(5000));
7589 	rdev_dec_pending(rdev, mddev);
7590 }
7591 EXPORT_SYMBOL(md_wait_for_blocked_rdev);
7592 
7593 
7594 /* Bad block management.
7595  * We can record which blocks on each device are 'bad' and so just
7596  * fail those blocks, or that stripe, rather than the whole device.
7597  * Entries in the bad-block table are 64bits wide.  This comprises:
7598  * Length of bad-range, in sectors: 0-511 for lengths 1-512
7599  * Start of bad-range, sector offset, 54 bits (allows 8 exbibytes)
7600  *  A 'shift' can be set so that larger blocks are tracked and
7601  *  consequently larger devices can be covered.
7602  * 'Acknowledged' flag - 1 bit. - the most significant bit.
7603  *
7604  * Locking of the bad-block table uses a seqlock so md_is_badblock
7605  * might need to retry if it is very unlucky.
7606  * We will sometimes want to check for bad blocks in a bi_end_io function,
7607  * so we use the write_seqlock_irq variant.
7608  *
7609  * When looking for a bad block we specify a range and want to
7610  * know if any block in the range is bad.  So we binary-search
7611  * to the last range that starts at-or-before the given endpoint,
7612  * (or "before the sector after the target range")
7613  * then see if it ends after the given start.
7614  * We return
7615  *  0 if there are no known bad blocks in the range
7616  *  1 if there are known bad block which are all acknowledged
7617  * -1 if there are bad blocks which have not yet been acknowledged in metadata.
7618  * plus the start/length of the first bad section we overlap.
7619  */
7620 int md_is_badblock(struct badblocks *bb, sector_t s, int sectors,
7621 		   sector_t *first_bad, int *bad_sectors)
7622 {
7623 	int hi;
7624 	int lo = 0;
7625 	u64 *p = bb->page;
7626 	int rv = 0;
7627 	sector_t target = s + sectors;
7628 	unsigned seq;
7629 
7630 	if (bb->shift > 0) {
7631 		/* round the start down, and the end up */
7632 		s >>= bb->shift;
7633 		target += (1<<bb->shift) - 1;
7634 		target >>= bb->shift;
7635 		sectors = target - s;
7636 	}
7637 	/* 'target' is now the first block after the bad range */
7638 
7639 retry:
7640 	seq = read_seqbegin(&bb->lock);
7641 
7642 	hi = bb->count;
7643 
7644 	/* Binary search between lo and hi for 'target'
7645 	 * i.e. for the last range that starts before 'target'
7646 	 */
7647 	/* INVARIANT: ranges before 'lo' and at-or-after 'hi'
7648 	 * are known not to be the last range before target.
7649 	 * VARIANT: hi-lo is the number of possible
7650 	 * ranges, and decreases until it reaches 1
7651 	 */
7652 	while (hi - lo > 1) {
7653 		int mid = (lo + hi) / 2;
7654 		sector_t a = BB_OFFSET(p[mid]);
7655 		if (a < target)
7656 			/* This could still be the one, earlier ranges
7657 			 * could not. */
7658 			lo = mid;
7659 		else
7660 			/* This and later ranges are definitely out. */
7661 			hi = mid;
7662 	}
7663 	/* 'lo' might be the last that started before target, but 'hi' isn't */
7664 	if (hi > lo) {
7665 		/* need to check all range that end after 's' to see if
7666 		 * any are unacknowledged.
7667 		 */
7668 		while (lo >= 0 &&
7669 		       BB_OFFSET(p[lo]) + BB_LEN(p[lo]) > s) {
7670 			if (BB_OFFSET(p[lo]) < target) {
7671 				/* starts before the end, and finishes after
7672 				 * the start, so they must overlap
7673 				 */
7674 				if (rv != -1 && BB_ACK(p[lo]))
7675 					rv = 1;
7676 				else
7677 					rv = -1;
7678 				*first_bad = BB_OFFSET(p[lo]);
7679 				*bad_sectors = BB_LEN(p[lo]);
7680 			}
7681 			lo--;
7682 		}
7683 	}
7684 
7685 	if (read_seqretry(&bb->lock, seq))
7686 		goto retry;
7687 
7688 	return rv;
7689 }
7690 EXPORT_SYMBOL_GPL(md_is_badblock);
7691 
7692 /*
7693  * Add a range of bad blocks to the table.
7694  * This might extend the table, or might contract it
7695  * if two adjacent ranges can be merged.
7696  * We binary-search to find the 'insertion' point, then
7697  * decide how best to handle it.
7698  */
7699 static int md_set_badblocks(struct badblocks *bb, sector_t s, int sectors,
7700 			    int acknowledged)
7701 {
7702 	u64 *p;
7703 	int lo, hi;
7704 	int rv = 1;
7705 
7706 	if (bb->shift < 0)
7707 		/* badblocks are disabled */
7708 		return 0;
7709 
7710 	if (bb->shift) {
7711 		/* round the start down, and the end up */
7712 		sector_t next = s + sectors;
7713 		s >>= bb->shift;
7714 		next += (1<<bb->shift) - 1;
7715 		next >>= bb->shift;
7716 		sectors = next - s;
7717 	}
7718 
7719 	write_seqlock_irq(&bb->lock);
7720 
7721 	p = bb->page;
7722 	lo = 0;
7723 	hi = bb->count;
7724 	/* Find the last range that starts at-or-before 's' */
7725 	while (hi - lo > 1) {
7726 		int mid = (lo + hi) / 2;
7727 		sector_t a = BB_OFFSET(p[mid]);
7728 		if (a <= s)
7729 			lo = mid;
7730 		else
7731 			hi = mid;
7732 	}
7733 	if (hi > lo && BB_OFFSET(p[lo]) > s)
7734 		hi = lo;
7735 
7736 	if (hi > lo) {
7737 		/* we found a range that might merge with the start
7738 		 * of our new range
7739 		 */
7740 		sector_t a = BB_OFFSET(p[lo]);
7741 		sector_t e = a + BB_LEN(p[lo]);
7742 		int ack = BB_ACK(p[lo]);
7743 		if (e >= s) {
7744 			/* Yes, we can merge with a previous range */
7745 			if (s == a && s + sectors >= e)
7746 				/* new range covers old */
7747 				ack = acknowledged;
7748 			else
7749 				ack = ack && acknowledged;
7750 
7751 			if (e < s + sectors)
7752 				e = s + sectors;
7753 			if (e - a <= BB_MAX_LEN) {
7754 				p[lo] = BB_MAKE(a, e-a, ack);
7755 				s = e;
7756 			} else {
7757 				/* does not all fit in one range,
7758 				 * make p[lo] maximal
7759 				 */
7760 				if (BB_LEN(p[lo]) != BB_MAX_LEN)
7761 					p[lo] = BB_MAKE(a, BB_MAX_LEN, ack);
7762 				s = a + BB_MAX_LEN;
7763 			}
7764 			sectors = e - s;
7765 		}
7766 	}
7767 	if (sectors && hi < bb->count) {
7768 		/* 'hi' points to the first range that starts after 's'.
7769 		 * Maybe we can merge with the start of that range */
7770 		sector_t a = BB_OFFSET(p[hi]);
7771 		sector_t e = a + BB_LEN(p[hi]);
7772 		int ack = BB_ACK(p[hi]);
7773 		if (a <= s + sectors) {
7774 			/* merging is possible */
7775 			if (e <= s + sectors) {
7776 				/* full overlap */
7777 				e = s + sectors;
7778 				ack = acknowledged;
7779 			} else
7780 				ack = ack && acknowledged;
7781 
7782 			a = s;
7783 			if (e - a <= BB_MAX_LEN) {
7784 				p[hi] = BB_MAKE(a, e-a, ack);
7785 				s = e;
7786 			} else {
7787 				p[hi] = BB_MAKE(a, BB_MAX_LEN, ack);
7788 				s = a + BB_MAX_LEN;
7789 			}
7790 			sectors = e - s;
7791 			lo = hi;
7792 			hi++;
7793 		}
7794 	}
7795 	if (sectors == 0 && hi < bb->count) {
7796 		/* we might be able to combine lo and hi */
7797 		/* Note: 's' is at the end of 'lo' */
7798 		sector_t a = BB_OFFSET(p[hi]);
7799 		int lolen = BB_LEN(p[lo]);
7800 		int hilen = BB_LEN(p[hi]);
7801 		int newlen = lolen + hilen - (s - a);
7802 		if (s >= a && newlen < BB_MAX_LEN) {
7803 			/* yes, we can combine them */
7804 			int ack = BB_ACK(p[lo]) && BB_ACK(p[hi]);
7805 			p[lo] = BB_MAKE(BB_OFFSET(p[lo]), newlen, ack);
7806 			memmove(p + hi, p + hi + 1,
7807 				(bb->count - hi - 1) * 8);
7808 			bb->count--;
7809 		}
7810 	}
7811 	while (sectors) {
7812 		/* didn't merge (it all).
7813 		 * Need to add a range just before 'hi' */
7814 		if (bb->count >= MD_MAX_BADBLOCKS) {
7815 			/* No room for more */
7816 			rv = 0;
7817 			break;
7818 		} else {
7819 			int this_sectors = sectors;
7820 			memmove(p + hi + 1, p + hi,
7821 				(bb->count - hi) * 8);
7822 			bb->count++;
7823 
7824 			if (this_sectors > BB_MAX_LEN)
7825 				this_sectors = BB_MAX_LEN;
7826 			p[hi] = BB_MAKE(s, this_sectors, acknowledged);
7827 			sectors -= this_sectors;
7828 			s += this_sectors;
7829 		}
7830 	}
7831 
7832 	bb->changed = 1;
7833 	if (!acknowledged)
7834 		bb->unacked_exist = 1;
7835 	write_sequnlock_irq(&bb->lock);
7836 
7837 	return rv;
7838 }
7839 
7840 int rdev_set_badblocks(struct md_rdev *rdev, sector_t s, int sectors,
7841 		       int acknowledged)
7842 {
7843 	int rv = md_set_badblocks(&rdev->badblocks,
7844 				  s + rdev->data_offset, sectors, acknowledged);
7845 	if (rv) {
7846 		/* Make sure they get written out promptly */
7847 		set_bit(MD_CHANGE_CLEAN, &rdev->mddev->flags);
7848 		md_wakeup_thread(rdev->mddev->thread);
7849 	}
7850 	return rv;
7851 }
7852 EXPORT_SYMBOL_GPL(rdev_set_badblocks);
7853 
7854 /*
7855  * Remove a range of bad blocks from the table.
7856  * This may involve extending the table if we spilt a region,
7857  * but it must not fail.  So if the table becomes full, we just
7858  * drop the remove request.
7859  */
7860 static int md_clear_badblocks(struct badblocks *bb, sector_t s, int sectors)
7861 {
7862 	u64 *p;
7863 	int lo, hi;
7864 	sector_t target = s + sectors;
7865 	int rv = 0;
7866 
7867 	if (bb->shift > 0) {
7868 		/* When clearing we round the start up and the end down.
7869 		 * This should not matter as the shift should align with
7870 		 * the block size and no rounding should ever be needed.
7871 		 * However it is better the think a block is bad when it
7872 		 * isn't than to think a block is not bad when it is.
7873 		 */
7874 		s += (1<<bb->shift) - 1;
7875 		s >>= bb->shift;
7876 		target >>= bb->shift;
7877 		sectors = target - s;
7878 	}
7879 
7880 	write_seqlock_irq(&bb->lock);
7881 
7882 	p = bb->page;
7883 	lo = 0;
7884 	hi = bb->count;
7885 	/* Find the last range that starts before 'target' */
7886 	while (hi - lo > 1) {
7887 		int mid = (lo + hi) / 2;
7888 		sector_t a = BB_OFFSET(p[mid]);
7889 		if (a < target)
7890 			lo = mid;
7891 		else
7892 			hi = mid;
7893 	}
7894 	if (hi > lo) {
7895 		/* p[lo] is the last range that could overlap the
7896 		 * current range.  Earlier ranges could also overlap,
7897 		 * but only this one can overlap the end of the range.
7898 		 */
7899 		if (BB_OFFSET(p[lo]) + BB_LEN(p[lo]) > target) {
7900 			/* Partial overlap, leave the tail of this range */
7901 			int ack = BB_ACK(p[lo]);
7902 			sector_t a = BB_OFFSET(p[lo]);
7903 			sector_t end = a + BB_LEN(p[lo]);
7904 
7905 			if (a < s) {
7906 				/* we need to split this range */
7907 				if (bb->count >= MD_MAX_BADBLOCKS) {
7908 					rv = 0;
7909 					goto out;
7910 				}
7911 				memmove(p+lo+1, p+lo, (bb->count - lo) * 8);
7912 				bb->count++;
7913 				p[lo] = BB_MAKE(a, s-a, ack);
7914 				lo++;
7915 			}
7916 			p[lo] = BB_MAKE(target, end - target, ack);
7917 			/* there is no longer an overlap */
7918 			hi = lo;
7919 			lo--;
7920 		}
7921 		while (lo >= 0 &&
7922 		       BB_OFFSET(p[lo]) + BB_LEN(p[lo]) > s) {
7923 			/* This range does overlap */
7924 			if (BB_OFFSET(p[lo]) < s) {
7925 				/* Keep the early parts of this range. */
7926 				int ack = BB_ACK(p[lo]);
7927 				sector_t start = BB_OFFSET(p[lo]);
7928 				p[lo] = BB_MAKE(start, s - start, ack);
7929 				/* now low doesn't overlap, so.. */
7930 				break;
7931 			}
7932 			lo--;
7933 		}
7934 		/* 'lo' is strictly before, 'hi' is strictly after,
7935 		 * anything between needs to be discarded
7936 		 */
7937 		if (hi - lo > 1) {
7938 			memmove(p+lo+1, p+hi, (bb->count - hi) * 8);
7939 			bb->count -= (hi - lo - 1);
7940 		}
7941 	}
7942 
7943 	bb->changed = 1;
7944 out:
7945 	write_sequnlock_irq(&bb->lock);
7946 	return rv;
7947 }
7948 
7949 int rdev_clear_badblocks(struct md_rdev *rdev, sector_t s, int sectors)
7950 {
7951 	return md_clear_badblocks(&rdev->badblocks,
7952 				  s + rdev->data_offset,
7953 				  sectors);
7954 }
7955 EXPORT_SYMBOL_GPL(rdev_clear_badblocks);
7956 
7957 /*
7958  * Acknowledge all bad blocks in a list.
7959  * This only succeeds if ->changed is clear.  It is used by
7960  * in-kernel metadata updates
7961  */
7962 void md_ack_all_badblocks(struct badblocks *bb)
7963 {
7964 	if (bb->page == NULL || bb->changed)
7965 		/* no point even trying */
7966 		return;
7967 	write_seqlock_irq(&bb->lock);
7968 
7969 	if (bb->changed == 0) {
7970 		u64 *p = bb->page;
7971 		int i;
7972 		for (i = 0; i < bb->count ; i++) {
7973 			if (!BB_ACK(p[i])) {
7974 				sector_t start = BB_OFFSET(p[i]);
7975 				int len = BB_LEN(p[i]);
7976 				p[i] = BB_MAKE(start, len, 1);
7977 			}
7978 		}
7979 		bb->unacked_exist = 0;
7980 	}
7981 	write_sequnlock_irq(&bb->lock);
7982 }
7983 EXPORT_SYMBOL_GPL(md_ack_all_badblocks);
7984 
7985 /* sysfs access to bad-blocks list.
7986  * We present two files.
7987  * 'bad-blocks' lists sector numbers and lengths of ranges that
7988  *    are recorded as bad.  The list is truncated to fit within
7989  *    the one-page limit of sysfs.
7990  *    Writing "sector length" to this file adds an acknowledged
7991  *    bad block list.
7992  * 'unacknowledged-bad-blocks' lists bad blocks that have not yet
7993  *    been acknowledged.  Writing to this file adds bad blocks
7994  *    without acknowledging them.  This is largely for testing.
7995  */
7996 
7997 static ssize_t
7998 badblocks_show(struct badblocks *bb, char *page, int unack)
7999 {
8000 	size_t len;
8001 	int i;
8002 	u64 *p = bb->page;
8003 	unsigned seq;
8004 
8005 	if (bb->shift < 0)
8006 		return 0;
8007 
8008 retry:
8009 	seq = read_seqbegin(&bb->lock);
8010 
8011 	len = 0;
8012 	i = 0;
8013 
8014 	while (len < PAGE_SIZE && i < bb->count) {
8015 		sector_t s = BB_OFFSET(p[i]);
8016 		unsigned int length = BB_LEN(p[i]);
8017 		int ack = BB_ACK(p[i]);
8018 		i++;
8019 
8020 		if (unack && ack)
8021 			continue;
8022 
8023 		len += snprintf(page+len, PAGE_SIZE-len, "%llu %u\n",
8024 				(unsigned long long)s << bb->shift,
8025 				length << bb->shift);
8026 	}
8027 	if (unack && len == 0)
8028 		bb->unacked_exist = 0;
8029 
8030 	if (read_seqretry(&bb->lock, seq))
8031 		goto retry;
8032 
8033 	return len;
8034 }
8035 
8036 #define DO_DEBUG 1
8037 
8038 static ssize_t
8039 badblocks_store(struct badblocks *bb, const char *page, size_t len, int unack)
8040 {
8041 	unsigned long long sector;
8042 	int length;
8043 	char newline;
8044 #ifdef DO_DEBUG
8045 	/* Allow clearing via sysfs *only* for testing/debugging.
8046 	 * Normally only a successful write may clear a badblock
8047 	 */
8048 	int clear = 0;
8049 	if (page[0] == '-') {
8050 		clear = 1;
8051 		page++;
8052 	}
8053 #endif /* DO_DEBUG */
8054 
8055 	switch (sscanf(page, "%llu %d%c", &sector, &length, &newline)) {
8056 	case 3:
8057 		if (newline != '\n')
8058 			return -EINVAL;
8059 	case 2:
8060 		if (length <= 0)
8061 			return -EINVAL;
8062 		break;
8063 	default:
8064 		return -EINVAL;
8065 	}
8066 
8067 #ifdef DO_DEBUG
8068 	if (clear) {
8069 		md_clear_badblocks(bb, sector, length);
8070 		return len;
8071 	}
8072 #endif /* DO_DEBUG */
8073 	if (md_set_badblocks(bb, sector, length, !unack))
8074 		return len;
8075 	else
8076 		return -ENOSPC;
8077 }
8078 
8079 static int md_notify_reboot(struct notifier_block *this,
8080 			    unsigned long code, void *x)
8081 {
8082 	struct list_head *tmp;
8083 	struct mddev *mddev;
8084 	int need_delay = 0;
8085 
8086 	if ((code == SYS_DOWN) || (code == SYS_HALT) || (code == SYS_POWER_OFF)) {
8087 
8088 		printk(KERN_INFO "md: stopping all md devices.\n");
8089 
8090 		for_each_mddev(mddev, tmp) {
8091 			if (mddev_trylock(mddev)) {
8092 				/* Force a switch to readonly even array
8093 				 * appears to still be in use.  Hence
8094 				 * the '100'.
8095 				 */
8096 				md_set_readonly(mddev, 100);
8097 				mddev_unlock(mddev);
8098 			}
8099 			need_delay = 1;
8100 		}
8101 		/*
8102 		 * certain more exotic SCSI devices are known to be
8103 		 * volatile wrt too early system reboots. While the
8104 		 * right place to handle this issue is the given
8105 		 * driver, we do want to have a safe RAID driver ...
8106 		 */
8107 		if (need_delay)
8108 			mdelay(1000*1);
8109 	}
8110 	return NOTIFY_DONE;
8111 }
8112 
8113 static struct notifier_block md_notifier = {
8114 	.notifier_call	= md_notify_reboot,
8115 	.next		= NULL,
8116 	.priority	= INT_MAX, /* before any real devices */
8117 };
8118 
8119 static void md_geninit(void)
8120 {
8121 	pr_debug("md: sizeof(mdp_super_t) = %d\n", (int)sizeof(mdp_super_t));
8122 
8123 	proc_create("mdstat", S_IRUGO, NULL, &md_seq_fops);
8124 }
8125 
8126 static int __init md_init(void)
8127 {
8128 	int ret = -ENOMEM;
8129 
8130 	md_wq = alloc_workqueue("md", WQ_MEM_RECLAIM, 0);
8131 	if (!md_wq)
8132 		goto err_wq;
8133 
8134 	md_misc_wq = alloc_workqueue("md_misc", 0, 0);
8135 	if (!md_misc_wq)
8136 		goto err_misc_wq;
8137 
8138 	if ((ret = register_blkdev(MD_MAJOR, "md")) < 0)
8139 		goto err_md;
8140 
8141 	if ((ret = register_blkdev(0, "mdp")) < 0)
8142 		goto err_mdp;
8143 	mdp_major = ret;
8144 
8145 	blk_register_region(MKDEV(MD_MAJOR, 0), 1UL<<MINORBITS, THIS_MODULE,
8146 			    md_probe, NULL, NULL);
8147 	blk_register_region(MKDEV(mdp_major, 0), 1UL<<MINORBITS, THIS_MODULE,
8148 			    md_probe, NULL, NULL);
8149 
8150 	register_reboot_notifier(&md_notifier);
8151 	raid_table_header = register_sysctl_table(raid_root_table);
8152 
8153 	md_geninit();
8154 	return 0;
8155 
8156 err_mdp:
8157 	unregister_blkdev(MD_MAJOR, "md");
8158 err_md:
8159 	destroy_workqueue(md_misc_wq);
8160 err_misc_wq:
8161 	destroy_workqueue(md_wq);
8162 err_wq:
8163 	return ret;
8164 }
8165 
8166 #ifndef MODULE
8167 
8168 /*
8169  * Searches all registered partitions for autorun RAID arrays
8170  * at boot time.
8171  */
8172 
8173 static LIST_HEAD(all_detected_devices);
8174 struct detected_devices_node {
8175 	struct list_head list;
8176 	dev_t dev;
8177 };
8178 
8179 void md_autodetect_dev(dev_t dev)
8180 {
8181 	struct detected_devices_node *node_detected_dev;
8182 
8183 	node_detected_dev = kzalloc(sizeof(*node_detected_dev), GFP_KERNEL);
8184 	if (node_detected_dev) {
8185 		node_detected_dev->dev = dev;
8186 		list_add_tail(&node_detected_dev->list, &all_detected_devices);
8187 	} else {
8188 		printk(KERN_CRIT "md: md_autodetect_dev: kzalloc failed"
8189 			", skipping dev(%d,%d)\n", MAJOR(dev), MINOR(dev));
8190 	}
8191 }
8192 
8193 
8194 static void autostart_arrays(int part)
8195 {
8196 	struct md_rdev *rdev;
8197 	struct detected_devices_node *node_detected_dev;
8198 	dev_t dev;
8199 	int i_scanned, i_passed;
8200 
8201 	i_scanned = 0;
8202 	i_passed = 0;
8203 
8204 	printk(KERN_INFO "md: Autodetecting RAID arrays.\n");
8205 
8206 	while (!list_empty(&all_detected_devices) && i_scanned < INT_MAX) {
8207 		i_scanned++;
8208 		node_detected_dev = list_entry(all_detected_devices.next,
8209 					struct detected_devices_node, list);
8210 		list_del(&node_detected_dev->list);
8211 		dev = node_detected_dev->dev;
8212 		kfree(node_detected_dev);
8213 		rdev = md_import_device(dev,0, 90);
8214 		if (IS_ERR(rdev))
8215 			continue;
8216 
8217 		if (test_bit(Faulty, &rdev->flags)) {
8218 			MD_BUG();
8219 			continue;
8220 		}
8221 		set_bit(AutoDetected, &rdev->flags);
8222 		list_add(&rdev->same_set, &pending_raid_disks);
8223 		i_passed++;
8224 	}
8225 
8226 	printk(KERN_INFO "md: Scanned %d and added %d devices.\n",
8227 						i_scanned, i_passed);
8228 
8229 	autorun_devices(part);
8230 }
8231 
8232 #endif /* !MODULE */
8233 
8234 static __exit void md_exit(void)
8235 {
8236 	struct mddev *mddev;
8237 	struct list_head *tmp;
8238 
8239 	blk_unregister_region(MKDEV(MD_MAJOR,0), 1U << MINORBITS);
8240 	blk_unregister_region(MKDEV(mdp_major,0), 1U << MINORBITS);
8241 
8242 	unregister_blkdev(MD_MAJOR,"md");
8243 	unregister_blkdev(mdp_major, "mdp");
8244 	unregister_reboot_notifier(&md_notifier);
8245 	unregister_sysctl_table(raid_table_header);
8246 	remove_proc_entry("mdstat", NULL);
8247 	for_each_mddev(mddev, tmp) {
8248 		export_array(mddev);
8249 		mddev->hold_active = 0;
8250 	}
8251 	destroy_workqueue(md_misc_wq);
8252 	destroy_workqueue(md_wq);
8253 }
8254 
8255 subsys_initcall(md_init);
8256 module_exit(md_exit)
8257 
8258 static int get_ro(char *buffer, struct kernel_param *kp)
8259 {
8260 	return sprintf(buffer, "%d", start_readonly);
8261 }
8262 static int set_ro(const char *val, struct kernel_param *kp)
8263 {
8264 	char *e;
8265 	int num = simple_strtoul(val, &e, 10);
8266 	if (*val && (*e == '\0' || *e == '\n')) {
8267 		start_readonly = num;
8268 		return 0;
8269 	}
8270 	return -EINVAL;
8271 }
8272 
8273 module_param_call(start_ro, set_ro, get_ro, NULL, S_IRUSR|S_IWUSR);
8274 module_param(start_dirty_degraded, int, S_IRUGO|S_IWUSR);
8275 
8276 module_param_call(new_array, add_named_array, NULL, NULL, S_IWUSR);
8277 
8278 EXPORT_SYMBOL(register_md_personality);
8279 EXPORT_SYMBOL(unregister_md_personality);
8280 EXPORT_SYMBOL(md_error);
8281 EXPORT_SYMBOL(md_done_sync);
8282 EXPORT_SYMBOL(md_write_start);
8283 EXPORT_SYMBOL(md_write_end);
8284 EXPORT_SYMBOL(md_register_thread);
8285 EXPORT_SYMBOL(md_unregister_thread);
8286 EXPORT_SYMBOL(md_wakeup_thread);
8287 EXPORT_SYMBOL(md_check_recovery);
8288 MODULE_LICENSE("GPL");
8289 MODULE_DESCRIPTION("MD RAID framework");
8290 MODULE_ALIAS("md");
8291 MODULE_ALIAS_BLOCKDEV_MAJOR(MD_MAJOR);
8292