xref: /linux/drivers/md/md.c (revision eecb20720f1b29019725515051e41bc7c079f91f)
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 void 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 cpu;
341 	unsigned int sectors;
342 
343 	if (mddev == NULL || mddev->pers == NULL
344 	    || !mddev->ready) {
345 		bio_io_error(bio);
346 		return;
347 	}
348 	smp_rmb(); /* Ensure implications of  'active' are visible */
349 	rcu_read_lock();
350 	if (mddev->suspended) {
351 		DEFINE_WAIT(__wait);
352 		for (;;) {
353 			prepare_to_wait(&mddev->sb_wait, &__wait,
354 					TASK_UNINTERRUPTIBLE);
355 			if (!mddev->suspended)
356 				break;
357 			rcu_read_unlock();
358 			schedule();
359 			rcu_read_lock();
360 		}
361 		finish_wait(&mddev->sb_wait, &__wait);
362 	}
363 	atomic_inc(&mddev->active_io);
364 	rcu_read_unlock();
365 
366 	/*
367 	 * save the sectors now since our bio can
368 	 * go away inside make_request
369 	 */
370 	sectors = bio_sectors(bio);
371 	mddev->pers->make_request(mddev, bio);
372 
373 	cpu = part_stat_lock();
374 	part_stat_inc(cpu, &mddev->gendisk->part0, ios[rw]);
375 	part_stat_add(cpu, &mddev->gendisk->part0, sectors[rw], sectors);
376 	part_stat_unlock();
377 
378 	if (atomic_dec_and_test(&mddev->active_io) && mddev->suspended)
379 		wake_up(&mddev->sb_wait);
380 }
381 
382 /* mddev_suspend makes sure no new requests are submitted
383  * to the device, and that any requests that have been submitted
384  * are completely handled.
385  * Once ->stop is called and completes, the module will be completely
386  * unused.
387  */
388 void mddev_suspend(struct mddev *mddev)
389 {
390 	BUG_ON(mddev->suspended);
391 	mddev->suspended = 1;
392 	synchronize_rcu();
393 	wait_event(mddev->sb_wait, atomic_read(&mddev->active_io) == 0);
394 	mddev->pers->quiesce(mddev, 1);
395 }
396 EXPORT_SYMBOL_GPL(mddev_suspend);
397 
398 void mddev_resume(struct mddev *mddev)
399 {
400 	mddev->suspended = 0;
401 	wake_up(&mddev->sb_wait);
402 	mddev->pers->quiesce(mddev, 0);
403 
404 	md_wakeup_thread(mddev->thread);
405 	md_wakeup_thread(mddev->sync_thread); /* possibly kick off a reshape */
406 }
407 EXPORT_SYMBOL_GPL(mddev_resume);
408 
409 int mddev_congested(struct mddev *mddev, int bits)
410 {
411 	return mddev->suspended;
412 }
413 EXPORT_SYMBOL(mddev_congested);
414 
415 /*
416  * Generic flush handling for md
417  */
418 
419 static void md_end_flush(struct bio *bio, int err)
420 {
421 	struct md_rdev *rdev = bio->bi_private;
422 	struct mddev *mddev = rdev->mddev;
423 
424 	rdev_dec_pending(rdev, mddev);
425 
426 	if (atomic_dec_and_test(&mddev->flush_pending)) {
427 		/* The pre-request flush has finished */
428 		queue_work(md_wq, &mddev->flush_work);
429 	}
430 	bio_put(bio);
431 }
432 
433 static void md_submit_flush_data(struct work_struct *ws);
434 
435 static void submit_flushes(struct work_struct *ws)
436 {
437 	struct mddev *mddev = container_of(ws, struct mddev, flush_work);
438 	struct md_rdev *rdev;
439 
440 	INIT_WORK(&mddev->flush_work, md_submit_flush_data);
441 	atomic_set(&mddev->flush_pending, 1);
442 	rcu_read_lock();
443 	list_for_each_entry_rcu(rdev, &mddev->disks, same_set)
444 		if (rdev->raid_disk >= 0 &&
445 		    !test_bit(Faulty, &rdev->flags)) {
446 			/* Take two references, one is dropped
447 			 * when request finishes, one after
448 			 * we reclaim rcu_read_lock
449 			 */
450 			struct bio *bi;
451 			atomic_inc(&rdev->nr_pending);
452 			atomic_inc(&rdev->nr_pending);
453 			rcu_read_unlock();
454 			bi = bio_alloc_mddev(GFP_KERNEL, 0, mddev);
455 			bi->bi_end_io = md_end_flush;
456 			bi->bi_private = rdev;
457 			bi->bi_bdev = rdev->bdev;
458 			atomic_inc(&mddev->flush_pending);
459 			submit_bio(WRITE_FLUSH, bi);
460 			rcu_read_lock();
461 			rdev_dec_pending(rdev, mddev);
462 		}
463 	rcu_read_unlock();
464 	if (atomic_dec_and_test(&mddev->flush_pending))
465 		queue_work(md_wq, &mddev->flush_work);
466 }
467 
468 static void md_submit_flush_data(struct work_struct *ws)
469 {
470 	struct mddev *mddev = container_of(ws, struct mddev, flush_work);
471 	struct bio *bio = mddev->flush_bio;
472 
473 	if (bio->bi_size == 0)
474 		/* an empty barrier - all done */
475 		bio_endio(bio, 0);
476 	else {
477 		bio->bi_rw &= ~REQ_FLUSH;
478 		mddev->pers->make_request(mddev, bio);
479 	}
480 
481 	mddev->flush_bio = NULL;
482 	wake_up(&mddev->sb_wait);
483 }
484 
485 void md_flush_request(struct mddev *mddev, struct bio *bio)
486 {
487 	spin_lock_irq(&mddev->write_lock);
488 	wait_event_lock_irq(mddev->sb_wait,
489 			    !mddev->flush_bio,
490 			    mddev->write_lock, /*nothing*/);
491 	mddev->flush_bio = bio;
492 	spin_unlock_irq(&mddev->write_lock);
493 
494 	INIT_WORK(&mddev->flush_work, submit_flushes);
495 	queue_work(md_wq, &mddev->flush_work);
496 }
497 EXPORT_SYMBOL(md_flush_request);
498 
499 /* Support for plugging.
500  * This mirrors the plugging support in request_queue, but does not
501  * require having a whole queue or request structures.
502  * We allocate an md_plug_cb for each md device and each thread it gets
503  * plugged on.  This links tot the private plug_handle structure in the
504  * personality data where we keep a count of the number of outstanding
505  * plugs so other code can see if a plug is active.
506  */
507 struct md_plug_cb {
508 	struct blk_plug_cb cb;
509 	struct mddev *mddev;
510 };
511 
512 static void plugger_unplug(struct blk_plug_cb *cb)
513 {
514 	struct md_plug_cb *mdcb = container_of(cb, struct md_plug_cb, cb);
515 	if (atomic_dec_and_test(&mdcb->mddev->plug_cnt))
516 		md_wakeup_thread(mdcb->mddev->thread);
517 	kfree(mdcb);
518 }
519 
520 /* Check that an unplug wakeup will come shortly.
521  * If not, wakeup the md thread immediately
522  */
523 int mddev_check_plugged(struct mddev *mddev)
524 {
525 	struct blk_plug *plug = current->plug;
526 	struct md_plug_cb *mdcb;
527 
528 	if (!plug)
529 		return 0;
530 
531 	list_for_each_entry(mdcb, &plug->cb_list, cb.list) {
532 		if (mdcb->cb.callback == plugger_unplug &&
533 		    mdcb->mddev == mddev) {
534 			/* Already on the list, move to top */
535 			if (mdcb != list_first_entry(&plug->cb_list,
536 						    struct md_plug_cb,
537 						    cb.list))
538 				list_move(&mdcb->cb.list, &plug->cb_list);
539 			return 1;
540 		}
541 	}
542 	/* Not currently on the callback list */
543 	mdcb = kmalloc(sizeof(*mdcb), GFP_ATOMIC);
544 	if (!mdcb)
545 		return 0;
546 
547 	mdcb->mddev = mddev;
548 	mdcb->cb.callback = plugger_unplug;
549 	atomic_inc(&mddev->plug_cnt);
550 	list_add(&mdcb->cb.list, &plug->cb_list);
551 	return 1;
552 }
553 EXPORT_SYMBOL_GPL(mddev_check_plugged);
554 
555 static inline struct mddev *mddev_get(struct mddev *mddev)
556 {
557 	atomic_inc(&mddev->active);
558 	return mddev;
559 }
560 
561 static void mddev_delayed_delete(struct work_struct *ws);
562 
563 static void mddev_put(struct mddev *mddev)
564 {
565 	struct bio_set *bs = NULL;
566 
567 	if (!atomic_dec_and_lock(&mddev->active, &all_mddevs_lock))
568 		return;
569 	if (!mddev->raid_disks && list_empty(&mddev->disks) &&
570 	    mddev->ctime == 0 && !mddev->hold_active) {
571 		/* Array is not configured at all, and not held active,
572 		 * so destroy it */
573 		list_del_init(&mddev->all_mddevs);
574 		bs = mddev->bio_set;
575 		mddev->bio_set = NULL;
576 		if (mddev->gendisk) {
577 			/* We did a probe so need to clean up.  Call
578 			 * queue_work inside the spinlock so that
579 			 * flush_workqueue() after mddev_find will
580 			 * succeed in waiting for the work to be done.
581 			 */
582 			INIT_WORK(&mddev->del_work, mddev_delayed_delete);
583 			queue_work(md_misc_wq, &mddev->del_work);
584 		} else
585 			kfree(mddev);
586 	}
587 	spin_unlock(&all_mddevs_lock);
588 	if (bs)
589 		bioset_free(bs);
590 }
591 
592 void mddev_init(struct mddev *mddev)
593 {
594 	mutex_init(&mddev->open_mutex);
595 	mutex_init(&mddev->reconfig_mutex);
596 	mutex_init(&mddev->bitmap_info.mutex);
597 	INIT_LIST_HEAD(&mddev->disks);
598 	INIT_LIST_HEAD(&mddev->all_mddevs);
599 	init_timer(&mddev->safemode_timer);
600 	atomic_set(&mddev->active, 1);
601 	atomic_set(&mddev->openers, 0);
602 	atomic_set(&mddev->active_io, 0);
603 	atomic_set(&mddev->plug_cnt, 0);
604 	spin_lock_init(&mddev->write_lock);
605 	atomic_set(&mddev->flush_pending, 0);
606 	init_waitqueue_head(&mddev->sb_wait);
607 	init_waitqueue_head(&mddev->recovery_wait);
608 	mddev->reshape_position = MaxSector;
609 	mddev->resync_min = 0;
610 	mddev->resync_max = MaxSector;
611 	mddev->level = LEVEL_NONE;
612 }
613 EXPORT_SYMBOL_GPL(mddev_init);
614 
615 static struct mddev * mddev_find(dev_t unit)
616 {
617 	struct mddev *mddev, *new = NULL;
618 
619 	if (unit && MAJOR(unit) != MD_MAJOR)
620 		unit &= ~((1<<MdpMinorShift)-1);
621 
622  retry:
623 	spin_lock(&all_mddevs_lock);
624 
625 	if (unit) {
626 		list_for_each_entry(mddev, &all_mddevs, all_mddevs)
627 			if (mddev->unit == unit) {
628 				mddev_get(mddev);
629 				spin_unlock(&all_mddevs_lock);
630 				kfree(new);
631 				return mddev;
632 			}
633 
634 		if (new) {
635 			list_add(&new->all_mddevs, &all_mddevs);
636 			spin_unlock(&all_mddevs_lock);
637 			new->hold_active = UNTIL_IOCTL;
638 			return new;
639 		}
640 	} else if (new) {
641 		/* find an unused unit number */
642 		static int next_minor = 512;
643 		int start = next_minor;
644 		int is_free = 0;
645 		int dev = 0;
646 		while (!is_free) {
647 			dev = MKDEV(MD_MAJOR, next_minor);
648 			next_minor++;
649 			if (next_minor > MINORMASK)
650 				next_minor = 0;
651 			if (next_minor == start) {
652 				/* Oh dear, all in use. */
653 				spin_unlock(&all_mddevs_lock);
654 				kfree(new);
655 				return NULL;
656 			}
657 
658 			is_free = 1;
659 			list_for_each_entry(mddev, &all_mddevs, all_mddevs)
660 				if (mddev->unit == dev) {
661 					is_free = 0;
662 					break;
663 				}
664 		}
665 		new->unit = dev;
666 		new->md_minor = MINOR(dev);
667 		new->hold_active = UNTIL_STOP;
668 		list_add(&new->all_mddevs, &all_mddevs);
669 		spin_unlock(&all_mddevs_lock);
670 		return new;
671 	}
672 	spin_unlock(&all_mddevs_lock);
673 
674 	new = kzalloc(sizeof(*new), GFP_KERNEL);
675 	if (!new)
676 		return NULL;
677 
678 	new->unit = unit;
679 	if (MAJOR(unit) == MD_MAJOR)
680 		new->md_minor = MINOR(unit);
681 	else
682 		new->md_minor = MINOR(unit) >> MdpMinorShift;
683 
684 	mddev_init(new);
685 
686 	goto retry;
687 }
688 
689 static inline int mddev_lock(struct mddev * mddev)
690 {
691 	return mutex_lock_interruptible(&mddev->reconfig_mutex);
692 }
693 
694 static inline int mddev_is_locked(struct mddev *mddev)
695 {
696 	return mutex_is_locked(&mddev->reconfig_mutex);
697 }
698 
699 static inline int mddev_trylock(struct mddev * mddev)
700 {
701 	return mutex_trylock(&mddev->reconfig_mutex);
702 }
703 
704 static struct attribute_group md_redundancy_group;
705 
706 static void mddev_unlock(struct mddev * mddev)
707 {
708 	if (mddev->to_remove) {
709 		/* These cannot be removed under reconfig_mutex as
710 		 * an access to the files will try to take reconfig_mutex
711 		 * while holding the file unremovable, which leads to
712 		 * a deadlock.
713 		 * So hold set sysfs_active while the remove in happeing,
714 		 * and anything else which might set ->to_remove or my
715 		 * otherwise change the sysfs namespace will fail with
716 		 * -EBUSY if sysfs_active is still set.
717 		 * We set sysfs_active under reconfig_mutex and elsewhere
718 		 * test it under the same mutex to ensure its correct value
719 		 * is seen.
720 		 */
721 		struct attribute_group *to_remove = mddev->to_remove;
722 		mddev->to_remove = NULL;
723 		mddev->sysfs_active = 1;
724 		mutex_unlock(&mddev->reconfig_mutex);
725 
726 		if (mddev->kobj.sd) {
727 			if (to_remove != &md_redundancy_group)
728 				sysfs_remove_group(&mddev->kobj, to_remove);
729 			if (mddev->pers == NULL ||
730 			    mddev->pers->sync_request == NULL) {
731 				sysfs_remove_group(&mddev->kobj, &md_redundancy_group);
732 				if (mddev->sysfs_action)
733 					sysfs_put(mddev->sysfs_action);
734 				mddev->sysfs_action = NULL;
735 			}
736 		}
737 		mddev->sysfs_active = 0;
738 	} else
739 		mutex_unlock(&mddev->reconfig_mutex);
740 
741 	/* As we've dropped the mutex we need a spinlock to
742 	 * make sure the thread doesn't disappear
743 	 */
744 	spin_lock(&pers_lock);
745 	md_wakeup_thread(mddev->thread);
746 	spin_unlock(&pers_lock);
747 }
748 
749 static struct md_rdev * find_rdev_nr(struct mddev *mddev, int nr)
750 {
751 	struct md_rdev *rdev;
752 
753 	list_for_each_entry(rdev, &mddev->disks, same_set)
754 		if (rdev->desc_nr == nr)
755 			return rdev;
756 
757 	return NULL;
758 }
759 
760 static struct md_rdev * find_rdev(struct mddev * mddev, dev_t dev)
761 {
762 	struct md_rdev *rdev;
763 
764 	list_for_each_entry(rdev, &mddev->disks, same_set)
765 		if (rdev->bdev->bd_dev == dev)
766 			return rdev;
767 
768 	return NULL;
769 }
770 
771 static struct md_personality *find_pers(int level, char *clevel)
772 {
773 	struct md_personality *pers;
774 	list_for_each_entry(pers, &pers_list, list) {
775 		if (level != LEVEL_NONE && pers->level == level)
776 			return pers;
777 		if (strcmp(pers->name, clevel)==0)
778 			return pers;
779 	}
780 	return NULL;
781 }
782 
783 /* return the offset of the super block in 512byte sectors */
784 static inline sector_t calc_dev_sboffset(struct md_rdev *rdev)
785 {
786 	sector_t num_sectors = i_size_read(rdev->bdev->bd_inode) / 512;
787 	return MD_NEW_SIZE_SECTORS(num_sectors);
788 }
789 
790 static int alloc_disk_sb(struct md_rdev * rdev)
791 {
792 	if (rdev->sb_page)
793 		MD_BUG();
794 
795 	rdev->sb_page = alloc_page(GFP_KERNEL);
796 	if (!rdev->sb_page) {
797 		printk(KERN_ALERT "md: out of memory.\n");
798 		return -ENOMEM;
799 	}
800 
801 	return 0;
802 }
803 
804 static void free_disk_sb(struct md_rdev * rdev)
805 {
806 	if (rdev->sb_page) {
807 		put_page(rdev->sb_page);
808 		rdev->sb_loaded = 0;
809 		rdev->sb_page = NULL;
810 		rdev->sb_start = 0;
811 		rdev->sectors = 0;
812 	}
813 	if (rdev->bb_page) {
814 		put_page(rdev->bb_page);
815 		rdev->bb_page = NULL;
816 	}
817 }
818 
819 
820 static void super_written(struct bio *bio, int error)
821 {
822 	struct md_rdev *rdev = bio->bi_private;
823 	struct mddev *mddev = rdev->mddev;
824 
825 	if (error || !test_bit(BIO_UPTODATE, &bio->bi_flags)) {
826 		printk("md: super_written gets error=%d, uptodate=%d\n",
827 		       error, test_bit(BIO_UPTODATE, &bio->bi_flags));
828 		WARN_ON(test_bit(BIO_UPTODATE, &bio->bi_flags));
829 		md_error(mddev, rdev);
830 	}
831 
832 	if (atomic_dec_and_test(&mddev->pending_writes))
833 		wake_up(&mddev->sb_wait);
834 	bio_put(bio);
835 }
836 
837 void md_super_write(struct mddev *mddev, struct md_rdev *rdev,
838 		   sector_t sector, int size, struct page *page)
839 {
840 	/* write first size bytes of page to sector of rdev
841 	 * Increment mddev->pending_writes before returning
842 	 * and decrement it on completion, waking up sb_wait
843 	 * if zero is reached.
844 	 * If an error occurred, call md_error
845 	 */
846 	struct bio *bio = bio_alloc_mddev(GFP_NOIO, 1, mddev);
847 
848 	bio->bi_bdev = rdev->meta_bdev ? rdev->meta_bdev : rdev->bdev;
849 	bio->bi_sector = sector;
850 	bio_add_page(bio, page, size, 0);
851 	bio->bi_private = rdev;
852 	bio->bi_end_io = super_written;
853 
854 	atomic_inc(&mddev->pending_writes);
855 	submit_bio(WRITE_FLUSH_FUA, bio);
856 }
857 
858 void md_super_wait(struct mddev *mddev)
859 {
860 	/* wait for all superblock writes that were scheduled to complete */
861 	DEFINE_WAIT(wq);
862 	for(;;) {
863 		prepare_to_wait(&mddev->sb_wait, &wq, TASK_UNINTERRUPTIBLE);
864 		if (atomic_read(&mddev->pending_writes)==0)
865 			break;
866 		schedule();
867 	}
868 	finish_wait(&mddev->sb_wait, &wq);
869 }
870 
871 static void bi_complete(struct bio *bio, int error)
872 {
873 	complete((struct completion*)bio->bi_private);
874 }
875 
876 int sync_page_io(struct md_rdev *rdev, sector_t sector, int size,
877 		 struct page *page, int rw, bool metadata_op)
878 {
879 	struct bio *bio = bio_alloc_mddev(GFP_NOIO, 1, rdev->mddev);
880 	struct completion event;
881 	int ret;
882 
883 	rw |= REQ_SYNC;
884 
885 	bio->bi_bdev = (metadata_op && rdev->meta_bdev) ?
886 		rdev->meta_bdev : rdev->bdev;
887 	if (metadata_op)
888 		bio->bi_sector = sector + rdev->sb_start;
889 	else
890 		bio->bi_sector = sector + rdev->data_offset;
891 	bio_add_page(bio, page, size, 0);
892 	init_completion(&event);
893 	bio->bi_private = &event;
894 	bio->bi_end_io = bi_complete;
895 	submit_bio(rw, bio);
896 	wait_for_completion(&event);
897 
898 	ret = test_bit(BIO_UPTODATE, &bio->bi_flags);
899 	bio_put(bio);
900 	return ret;
901 }
902 EXPORT_SYMBOL_GPL(sync_page_io);
903 
904 static int read_disk_sb(struct md_rdev * rdev, int size)
905 {
906 	char b[BDEVNAME_SIZE];
907 	if (!rdev->sb_page) {
908 		MD_BUG();
909 		return -EINVAL;
910 	}
911 	if (rdev->sb_loaded)
912 		return 0;
913 
914 
915 	if (!sync_page_io(rdev, 0, size, rdev->sb_page, READ, true))
916 		goto fail;
917 	rdev->sb_loaded = 1;
918 	return 0;
919 
920 fail:
921 	printk(KERN_WARNING "md: disabled device %s, could not read superblock.\n",
922 		bdevname(rdev->bdev,b));
923 	return -EINVAL;
924 }
925 
926 static int uuid_equal(mdp_super_t *sb1, mdp_super_t *sb2)
927 {
928 	return 	sb1->set_uuid0 == sb2->set_uuid0 &&
929 		sb1->set_uuid1 == sb2->set_uuid1 &&
930 		sb1->set_uuid2 == sb2->set_uuid2 &&
931 		sb1->set_uuid3 == sb2->set_uuid3;
932 }
933 
934 static int sb_equal(mdp_super_t *sb1, mdp_super_t *sb2)
935 {
936 	int ret;
937 	mdp_super_t *tmp1, *tmp2;
938 
939 	tmp1 = kmalloc(sizeof(*tmp1),GFP_KERNEL);
940 	tmp2 = kmalloc(sizeof(*tmp2),GFP_KERNEL);
941 
942 	if (!tmp1 || !tmp2) {
943 		ret = 0;
944 		printk(KERN_INFO "md.c sb_equal(): failed to allocate memory!\n");
945 		goto abort;
946 	}
947 
948 	*tmp1 = *sb1;
949 	*tmp2 = *sb2;
950 
951 	/*
952 	 * nr_disks is not constant
953 	 */
954 	tmp1->nr_disks = 0;
955 	tmp2->nr_disks = 0;
956 
957 	ret = (memcmp(tmp1, tmp2, MD_SB_GENERIC_CONSTANT_WORDS * 4) == 0);
958 abort:
959 	kfree(tmp1);
960 	kfree(tmp2);
961 	return ret;
962 }
963 
964 
965 static u32 md_csum_fold(u32 csum)
966 {
967 	csum = (csum & 0xffff) + (csum >> 16);
968 	return (csum & 0xffff) + (csum >> 16);
969 }
970 
971 static unsigned int calc_sb_csum(mdp_super_t * sb)
972 {
973 	u64 newcsum = 0;
974 	u32 *sb32 = (u32*)sb;
975 	int i;
976 	unsigned int disk_csum, csum;
977 
978 	disk_csum = sb->sb_csum;
979 	sb->sb_csum = 0;
980 
981 	for (i = 0; i < MD_SB_BYTES/4 ; i++)
982 		newcsum += sb32[i];
983 	csum = (newcsum & 0xffffffff) + (newcsum>>32);
984 
985 
986 #ifdef CONFIG_ALPHA
987 	/* This used to use csum_partial, which was wrong for several
988 	 * reasons including that different results are returned on
989 	 * different architectures.  It isn't critical that we get exactly
990 	 * the same return value as before (we always csum_fold before
991 	 * testing, and that removes any differences).  However as we
992 	 * know that csum_partial always returned a 16bit value on
993 	 * alphas, do a fold to maximise conformity to previous behaviour.
994 	 */
995 	sb->sb_csum = md_csum_fold(disk_csum);
996 #else
997 	sb->sb_csum = disk_csum;
998 #endif
999 	return csum;
1000 }
1001 
1002 
1003 /*
1004  * Handle superblock details.
1005  * We want to be able to handle multiple superblock formats
1006  * so we have a common interface to them all, and an array of
1007  * different handlers.
1008  * We rely on user-space to write the initial superblock, and support
1009  * reading and updating of superblocks.
1010  * Interface methods are:
1011  *   int load_super(struct md_rdev *dev, struct md_rdev *refdev, int minor_version)
1012  *      loads and validates a superblock on dev.
1013  *      if refdev != NULL, compare superblocks on both devices
1014  *    Return:
1015  *      0 - dev has a superblock that is compatible with refdev
1016  *      1 - dev has a superblock that is compatible and newer than refdev
1017  *          so dev should be used as the refdev in future
1018  *     -EINVAL superblock incompatible or invalid
1019  *     -othererror e.g. -EIO
1020  *
1021  *   int validate_super(struct mddev *mddev, struct md_rdev *dev)
1022  *      Verify that dev is acceptable into mddev.
1023  *       The first time, mddev->raid_disks will be 0, and data from
1024  *       dev should be merged in.  Subsequent calls check that dev
1025  *       is new enough.  Return 0 or -EINVAL
1026  *
1027  *   void sync_super(struct mddev *mddev, struct md_rdev *dev)
1028  *     Update the superblock for rdev with data in mddev
1029  *     This does not write to disc.
1030  *
1031  */
1032 
1033 struct super_type  {
1034 	char		    *name;
1035 	struct module	    *owner;
1036 	int		    (*load_super)(struct md_rdev *rdev, struct md_rdev *refdev,
1037 					  int minor_version);
1038 	int		    (*validate_super)(struct mddev *mddev, struct md_rdev *rdev);
1039 	void		    (*sync_super)(struct mddev *mddev, struct md_rdev *rdev);
1040 	unsigned long long  (*rdev_size_change)(struct md_rdev *rdev,
1041 						sector_t num_sectors);
1042 };
1043 
1044 /*
1045  * Check that the given mddev has no bitmap.
1046  *
1047  * This function is called from the run method of all personalities that do not
1048  * support bitmaps. It prints an error message and returns non-zero if mddev
1049  * has a bitmap. Otherwise, it returns 0.
1050  *
1051  */
1052 int md_check_no_bitmap(struct mddev *mddev)
1053 {
1054 	if (!mddev->bitmap_info.file && !mddev->bitmap_info.offset)
1055 		return 0;
1056 	printk(KERN_ERR "%s: bitmaps are not supported for %s\n",
1057 		mdname(mddev), mddev->pers->name);
1058 	return 1;
1059 }
1060 EXPORT_SYMBOL(md_check_no_bitmap);
1061 
1062 /*
1063  * load_super for 0.90.0
1064  */
1065 static int super_90_load(struct md_rdev *rdev, struct md_rdev *refdev, int minor_version)
1066 {
1067 	char b[BDEVNAME_SIZE], b2[BDEVNAME_SIZE];
1068 	mdp_super_t *sb;
1069 	int ret;
1070 
1071 	/*
1072 	 * Calculate the position of the superblock (512byte sectors),
1073 	 * it's at the end of the disk.
1074 	 *
1075 	 * It also happens to be a multiple of 4Kb.
1076 	 */
1077 	rdev->sb_start = calc_dev_sboffset(rdev);
1078 
1079 	ret = read_disk_sb(rdev, MD_SB_BYTES);
1080 	if (ret) return ret;
1081 
1082 	ret = -EINVAL;
1083 
1084 	bdevname(rdev->bdev, b);
1085 	sb = page_address(rdev->sb_page);
1086 
1087 	if (sb->md_magic != MD_SB_MAGIC) {
1088 		printk(KERN_ERR "md: invalid raid superblock magic on %s\n",
1089 		       b);
1090 		goto abort;
1091 	}
1092 
1093 	if (sb->major_version != 0 ||
1094 	    sb->minor_version < 90 ||
1095 	    sb->minor_version > 91) {
1096 		printk(KERN_WARNING "Bad version number %d.%d on %s\n",
1097 			sb->major_version, sb->minor_version,
1098 			b);
1099 		goto abort;
1100 	}
1101 
1102 	if (sb->raid_disks <= 0)
1103 		goto abort;
1104 
1105 	if (md_csum_fold(calc_sb_csum(sb)) != md_csum_fold(sb->sb_csum)) {
1106 		printk(KERN_WARNING "md: invalid superblock checksum on %s\n",
1107 			b);
1108 		goto abort;
1109 	}
1110 
1111 	rdev->preferred_minor = sb->md_minor;
1112 	rdev->data_offset = 0;
1113 	rdev->sb_size = MD_SB_BYTES;
1114 	rdev->badblocks.shift = -1;
1115 
1116 	if (sb->level == LEVEL_MULTIPATH)
1117 		rdev->desc_nr = -1;
1118 	else
1119 		rdev->desc_nr = sb->this_disk.number;
1120 
1121 	if (!refdev) {
1122 		ret = 1;
1123 	} else {
1124 		__u64 ev1, ev2;
1125 		mdp_super_t *refsb = page_address(refdev->sb_page);
1126 		if (!uuid_equal(refsb, sb)) {
1127 			printk(KERN_WARNING "md: %s has different UUID to %s\n",
1128 				b, bdevname(refdev->bdev,b2));
1129 			goto abort;
1130 		}
1131 		if (!sb_equal(refsb, sb)) {
1132 			printk(KERN_WARNING "md: %s has same UUID"
1133 			       " but different superblock to %s\n",
1134 			       b, bdevname(refdev->bdev, b2));
1135 			goto abort;
1136 		}
1137 		ev1 = md_event(sb);
1138 		ev2 = md_event(refsb);
1139 		if (ev1 > ev2)
1140 			ret = 1;
1141 		else
1142 			ret = 0;
1143 	}
1144 	rdev->sectors = rdev->sb_start;
1145 	/* Limit to 4TB as metadata cannot record more than that */
1146 	if (rdev->sectors >= (2ULL << 32))
1147 		rdev->sectors = (2ULL << 32) - 2;
1148 
1149 	if (rdev->sectors < ((sector_t)sb->size) * 2 && sb->level >= 1)
1150 		/* "this cannot possibly happen" ... */
1151 		ret = -EINVAL;
1152 
1153  abort:
1154 	return ret;
1155 }
1156 
1157 /*
1158  * validate_super for 0.90.0
1159  */
1160 static int super_90_validate(struct mddev *mddev, struct md_rdev *rdev)
1161 {
1162 	mdp_disk_t *desc;
1163 	mdp_super_t *sb = page_address(rdev->sb_page);
1164 	__u64 ev1 = md_event(sb);
1165 
1166 	rdev->raid_disk = -1;
1167 	clear_bit(Faulty, &rdev->flags);
1168 	clear_bit(In_sync, &rdev->flags);
1169 	clear_bit(WriteMostly, &rdev->flags);
1170 
1171 	if (mddev->raid_disks == 0) {
1172 		mddev->major_version = 0;
1173 		mddev->minor_version = sb->minor_version;
1174 		mddev->patch_version = sb->patch_version;
1175 		mddev->external = 0;
1176 		mddev->chunk_sectors = sb->chunk_size >> 9;
1177 		mddev->ctime = sb->ctime;
1178 		mddev->utime = sb->utime;
1179 		mddev->level = sb->level;
1180 		mddev->clevel[0] = 0;
1181 		mddev->layout = sb->layout;
1182 		mddev->raid_disks = sb->raid_disks;
1183 		mddev->dev_sectors = ((sector_t)sb->size) * 2;
1184 		mddev->events = ev1;
1185 		mddev->bitmap_info.offset = 0;
1186 		mddev->bitmap_info.default_offset = MD_SB_BYTES >> 9;
1187 
1188 		if (mddev->minor_version >= 91) {
1189 			mddev->reshape_position = sb->reshape_position;
1190 			mddev->delta_disks = sb->delta_disks;
1191 			mddev->new_level = sb->new_level;
1192 			mddev->new_layout = sb->new_layout;
1193 			mddev->new_chunk_sectors = sb->new_chunk >> 9;
1194 		} else {
1195 			mddev->reshape_position = MaxSector;
1196 			mddev->delta_disks = 0;
1197 			mddev->new_level = mddev->level;
1198 			mddev->new_layout = mddev->layout;
1199 			mddev->new_chunk_sectors = mddev->chunk_sectors;
1200 		}
1201 
1202 		if (sb->state & (1<<MD_SB_CLEAN))
1203 			mddev->recovery_cp = MaxSector;
1204 		else {
1205 			if (sb->events_hi == sb->cp_events_hi &&
1206 				sb->events_lo == sb->cp_events_lo) {
1207 				mddev->recovery_cp = sb->recovery_cp;
1208 			} else
1209 				mddev->recovery_cp = 0;
1210 		}
1211 
1212 		memcpy(mddev->uuid+0, &sb->set_uuid0, 4);
1213 		memcpy(mddev->uuid+4, &sb->set_uuid1, 4);
1214 		memcpy(mddev->uuid+8, &sb->set_uuid2, 4);
1215 		memcpy(mddev->uuid+12,&sb->set_uuid3, 4);
1216 
1217 		mddev->max_disks = MD_SB_DISKS;
1218 
1219 		if (sb->state & (1<<MD_SB_BITMAP_PRESENT) &&
1220 		    mddev->bitmap_info.file == NULL)
1221 			mddev->bitmap_info.offset =
1222 				mddev->bitmap_info.default_offset;
1223 
1224 	} else if (mddev->pers == NULL) {
1225 		/* Insist on good event counter while assembling, except
1226 		 * for spares (which don't need an event count) */
1227 		++ev1;
1228 		if (sb->disks[rdev->desc_nr].state & (
1229 			    (1<<MD_DISK_SYNC) | (1 << MD_DISK_ACTIVE)))
1230 			if (ev1 < mddev->events)
1231 				return -EINVAL;
1232 	} else if (mddev->bitmap) {
1233 		/* if adding to array with a bitmap, then we can accept an
1234 		 * older device ... but not too old.
1235 		 */
1236 		if (ev1 < mddev->bitmap->events_cleared)
1237 			return 0;
1238 	} else {
1239 		if (ev1 < mddev->events)
1240 			/* just a hot-add of a new device, leave raid_disk at -1 */
1241 			return 0;
1242 	}
1243 
1244 	if (mddev->level != LEVEL_MULTIPATH) {
1245 		desc = sb->disks + rdev->desc_nr;
1246 
1247 		if (desc->state & (1<<MD_DISK_FAULTY))
1248 			set_bit(Faulty, &rdev->flags);
1249 		else if (desc->state & (1<<MD_DISK_SYNC) /* &&
1250 			    desc->raid_disk < mddev->raid_disks */) {
1251 			set_bit(In_sync, &rdev->flags);
1252 			rdev->raid_disk = desc->raid_disk;
1253 		} else if (desc->state & (1<<MD_DISK_ACTIVE)) {
1254 			/* active but not in sync implies recovery up to
1255 			 * reshape position.  We don't know exactly where
1256 			 * that is, so set to zero for now */
1257 			if (mddev->minor_version >= 91) {
1258 				rdev->recovery_offset = 0;
1259 				rdev->raid_disk = desc->raid_disk;
1260 			}
1261 		}
1262 		if (desc->state & (1<<MD_DISK_WRITEMOSTLY))
1263 			set_bit(WriteMostly, &rdev->flags);
1264 	} else /* MULTIPATH are always insync */
1265 		set_bit(In_sync, &rdev->flags);
1266 	return 0;
1267 }
1268 
1269 /*
1270  * sync_super for 0.90.0
1271  */
1272 static void super_90_sync(struct mddev *mddev, struct md_rdev *rdev)
1273 {
1274 	mdp_super_t *sb;
1275 	struct md_rdev *rdev2;
1276 	int next_spare = mddev->raid_disks;
1277 
1278 
1279 	/* make rdev->sb match mddev data..
1280 	 *
1281 	 * 1/ zero out disks
1282 	 * 2/ Add info for each disk, keeping track of highest desc_nr (next_spare);
1283 	 * 3/ any empty disks < next_spare become removed
1284 	 *
1285 	 * disks[0] gets initialised to REMOVED because
1286 	 * we cannot be sure from other fields if it has
1287 	 * been initialised or not.
1288 	 */
1289 	int i;
1290 	int active=0, working=0,failed=0,spare=0,nr_disks=0;
1291 
1292 	rdev->sb_size = MD_SB_BYTES;
1293 
1294 	sb = page_address(rdev->sb_page);
1295 
1296 	memset(sb, 0, sizeof(*sb));
1297 
1298 	sb->md_magic = MD_SB_MAGIC;
1299 	sb->major_version = mddev->major_version;
1300 	sb->patch_version = mddev->patch_version;
1301 	sb->gvalid_words  = 0; /* ignored */
1302 	memcpy(&sb->set_uuid0, mddev->uuid+0, 4);
1303 	memcpy(&sb->set_uuid1, mddev->uuid+4, 4);
1304 	memcpy(&sb->set_uuid2, mddev->uuid+8, 4);
1305 	memcpy(&sb->set_uuid3, mddev->uuid+12,4);
1306 
1307 	sb->ctime = mddev->ctime;
1308 	sb->level = mddev->level;
1309 	sb->size = mddev->dev_sectors / 2;
1310 	sb->raid_disks = mddev->raid_disks;
1311 	sb->md_minor = mddev->md_minor;
1312 	sb->not_persistent = 0;
1313 	sb->utime = mddev->utime;
1314 	sb->state = 0;
1315 	sb->events_hi = (mddev->events>>32);
1316 	sb->events_lo = (u32)mddev->events;
1317 
1318 	if (mddev->reshape_position == MaxSector)
1319 		sb->minor_version = 90;
1320 	else {
1321 		sb->minor_version = 91;
1322 		sb->reshape_position = mddev->reshape_position;
1323 		sb->new_level = mddev->new_level;
1324 		sb->delta_disks = mddev->delta_disks;
1325 		sb->new_layout = mddev->new_layout;
1326 		sb->new_chunk = mddev->new_chunk_sectors << 9;
1327 	}
1328 	mddev->minor_version = sb->minor_version;
1329 	if (mddev->in_sync)
1330 	{
1331 		sb->recovery_cp = mddev->recovery_cp;
1332 		sb->cp_events_hi = (mddev->events>>32);
1333 		sb->cp_events_lo = (u32)mddev->events;
1334 		if (mddev->recovery_cp == MaxSector)
1335 			sb->state = (1<< MD_SB_CLEAN);
1336 	} else
1337 		sb->recovery_cp = 0;
1338 
1339 	sb->layout = mddev->layout;
1340 	sb->chunk_size = mddev->chunk_sectors << 9;
1341 
1342 	if (mddev->bitmap && mddev->bitmap_info.file == NULL)
1343 		sb->state |= (1<<MD_SB_BITMAP_PRESENT);
1344 
1345 	sb->disks[0].state = (1<<MD_DISK_REMOVED);
1346 	list_for_each_entry(rdev2, &mddev->disks, same_set) {
1347 		mdp_disk_t *d;
1348 		int desc_nr;
1349 		int is_active = test_bit(In_sync, &rdev2->flags);
1350 
1351 		if (rdev2->raid_disk >= 0 &&
1352 		    sb->minor_version >= 91)
1353 			/* we have nowhere to store the recovery_offset,
1354 			 * but if it is not below the reshape_position,
1355 			 * we can piggy-back on that.
1356 			 */
1357 			is_active = 1;
1358 		if (rdev2->raid_disk < 0 ||
1359 		    test_bit(Faulty, &rdev2->flags))
1360 			is_active = 0;
1361 		if (is_active)
1362 			desc_nr = rdev2->raid_disk;
1363 		else
1364 			desc_nr = next_spare++;
1365 		rdev2->desc_nr = desc_nr;
1366 		d = &sb->disks[rdev2->desc_nr];
1367 		nr_disks++;
1368 		d->number = rdev2->desc_nr;
1369 		d->major = MAJOR(rdev2->bdev->bd_dev);
1370 		d->minor = MINOR(rdev2->bdev->bd_dev);
1371 		if (is_active)
1372 			d->raid_disk = rdev2->raid_disk;
1373 		else
1374 			d->raid_disk = rdev2->desc_nr; /* compatibility */
1375 		if (test_bit(Faulty, &rdev2->flags))
1376 			d->state = (1<<MD_DISK_FAULTY);
1377 		else if (is_active) {
1378 			d->state = (1<<MD_DISK_ACTIVE);
1379 			if (test_bit(In_sync, &rdev2->flags))
1380 				d->state |= (1<<MD_DISK_SYNC);
1381 			active++;
1382 			working++;
1383 		} else {
1384 			d->state = 0;
1385 			spare++;
1386 			working++;
1387 		}
1388 		if (test_bit(WriteMostly, &rdev2->flags))
1389 			d->state |= (1<<MD_DISK_WRITEMOSTLY);
1390 	}
1391 	/* now set the "removed" and "faulty" bits on any missing devices */
1392 	for (i=0 ; i < mddev->raid_disks ; i++) {
1393 		mdp_disk_t *d = &sb->disks[i];
1394 		if (d->state == 0 && d->number == 0) {
1395 			d->number = i;
1396 			d->raid_disk = i;
1397 			d->state = (1<<MD_DISK_REMOVED);
1398 			d->state |= (1<<MD_DISK_FAULTY);
1399 			failed++;
1400 		}
1401 	}
1402 	sb->nr_disks = nr_disks;
1403 	sb->active_disks = active;
1404 	sb->working_disks = working;
1405 	sb->failed_disks = failed;
1406 	sb->spare_disks = spare;
1407 
1408 	sb->this_disk = sb->disks[rdev->desc_nr];
1409 	sb->sb_csum = calc_sb_csum(sb);
1410 }
1411 
1412 /*
1413  * rdev_size_change for 0.90.0
1414  */
1415 static unsigned long long
1416 super_90_rdev_size_change(struct md_rdev *rdev, sector_t num_sectors)
1417 {
1418 	if (num_sectors && num_sectors < rdev->mddev->dev_sectors)
1419 		return 0; /* component must fit device */
1420 	if (rdev->mddev->bitmap_info.offset)
1421 		return 0; /* can't move bitmap */
1422 	rdev->sb_start = calc_dev_sboffset(rdev);
1423 	if (!num_sectors || num_sectors > rdev->sb_start)
1424 		num_sectors = rdev->sb_start;
1425 	/* Limit to 4TB as metadata cannot record more than that.
1426 	 * 4TB == 2^32 KB, or 2*2^32 sectors.
1427 	 */
1428 	if (num_sectors >= (2ULL << 32))
1429 		num_sectors = (2ULL << 32) - 2;
1430 	md_super_write(rdev->mddev, rdev, rdev->sb_start, rdev->sb_size,
1431 		       rdev->sb_page);
1432 	md_super_wait(rdev->mddev);
1433 	return num_sectors;
1434 }
1435 
1436 
1437 /*
1438  * version 1 superblock
1439  */
1440 
1441 static __le32 calc_sb_1_csum(struct mdp_superblock_1 * sb)
1442 {
1443 	__le32 disk_csum;
1444 	u32 csum;
1445 	unsigned long long newcsum;
1446 	int size = 256 + le32_to_cpu(sb->max_dev)*2;
1447 	__le32 *isuper = (__le32*)sb;
1448 	int i;
1449 
1450 	disk_csum = sb->sb_csum;
1451 	sb->sb_csum = 0;
1452 	newcsum = 0;
1453 	for (i=0; size>=4; size -= 4 )
1454 		newcsum += le32_to_cpu(*isuper++);
1455 
1456 	if (size == 2)
1457 		newcsum += le16_to_cpu(*(__le16*) isuper);
1458 
1459 	csum = (newcsum & 0xffffffff) + (newcsum >> 32);
1460 	sb->sb_csum = disk_csum;
1461 	return cpu_to_le32(csum);
1462 }
1463 
1464 static int md_set_badblocks(struct badblocks *bb, sector_t s, int sectors,
1465 			    int acknowledged);
1466 static int super_1_load(struct md_rdev *rdev, struct md_rdev *refdev, int minor_version)
1467 {
1468 	struct mdp_superblock_1 *sb;
1469 	int ret;
1470 	sector_t sb_start;
1471 	char b[BDEVNAME_SIZE], b2[BDEVNAME_SIZE];
1472 	int bmask;
1473 
1474 	/*
1475 	 * Calculate the position of the superblock in 512byte sectors.
1476 	 * It is always aligned to a 4K boundary and
1477 	 * depeding on minor_version, it can be:
1478 	 * 0: At least 8K, but less than 12K, from end of device
1479 	 * 1: At start of device
1480 	 * 2: 4K from start of device.
1481 	 */
1482 	switch(minor_version) {
1483 	case 0:
1484 		sb_start = i_size_read(rdev->bdev->bd_inode) >> 9;
1485 		sb_start -= 8*2;
1486 		sb_start &= ~(sector_t)(4*2-1);
1487 		break;
1488 	case 1:
1489 		sb_start = 0;
1490 		break;
1491 	case 2:
1492 		sb_start = 8;
1493 		break;
1494 	default:
1495 		return -EINVAL;
1496 	}
1497 	rdev->sb_start = sb_start;
1498 
1499 	/* superblock is rarely larger than 1K, but it can be larger,
1500 	 * and it is safe to read 4k, so we do that
1501 	 */
1502 	ret = read_disk_sb(rdev, 4096);
1503 	if (ret) return ret;
1504 
1505 
1506 	sb = page_address(rdev->sb_page);
1507 
1508 	if (sb->magic != cpu_to_le32(MD_SB_MAGIC) ||
1509 	    sb->major_version != cpu_to_le32(1) ||
1510 	    le32_to_cpu(sb->max_dev) > (4096-256)/2 ||
1511 	    le64_to_cpu(sb->super_offset) != rdev->sb_start ||
1512 	    (le32_to_cpu(sb->feature_map) & ~MD_FEATURE_ALL) != 0)
1513 		return -EINVAL;
1514 
1515 	if (calc_sb_1_csum(sb) != sb->sb_csum) {
1516 		printk("md: invalid superblock checksum on %s\n",
1517 			bdevname(rdev->bdev,b));
1518 		return -EINVAL;
1519 	}
1520 	if (le64_to_cpu(sb->data_size) < 10) {
1521 		printk("md: data_size too small on %s\n",
1522 		       bdevname(rdev->bdev,b));
1523 		return -EINVAL;
1524 	}
1525 
1526 	rdev->preferred_minor = 0xffff;
1527 	rdev->data_offset = le64_to_cpu(sb->data_offset);
1528 	atomic_set(&rdev->corrected_errors, le32_to_cpu(sb->cnt_corrected_read));
1529 
1530 	rdev->sb_size = le32_to_cpu(sb->max_dev) * 2 + 256;
1531 	bmask = queue_logical_block_size(rdev->bdev->bd_disk->queue)-1;
1532 	if (rdev->sb_size & bmask)
1533 		rdev->sb_size = (rdev->sb_size | bmask) + 1;
1534 
1535 	if (minor_version
1536 	    && rdev->data_offset < sb_start + (rdev->sb_size/512))
1537 		return -EINVAL;
1538 
1539 	if (sb->level == cpu_to_le32(LEVEL_MULTIPATH))
1540 		rdev->desc_nr = -1;
1541 	else
1542 		rdev->desc_nr = le32_to_cpu(sb->dev_number);
1543 
1544 	if (!rdev->bb_page) {
1545 		rdev->bb_page = alloc_page(GFP_KERNEL);
1546 		if (!rdev->bb_page)
1547 			return -ENOMEM;
1548 	}
1549 	if ((le32_to_cpu(sb->feature_map) & MD_FEATURE_BAD_BLOCKS) &&
1550 	    rdev->badblocks.count == 0) {
1551 		/* need to load the bad block list.
1552 		 * Currently we limit it to one page.
1553 		 */
1554 		s32 offset;
1555 		sector_t bb_sector;
1556 		u64 *bbp;
1557 		int i;
1558 		int sectors = le16_to_cpu(sb->bblog_size);
1559 		if (sectors > (PAGE_SIZE / 512))
1560 			return -EINVAL;
1561 		offset = le32_to_cpu(sb->bblog_offset);
1562 		if (offset == 0)
1563 			return -EINVAL;
1564 		bb_sector = (long long)offset;
1565 		if (!sync_page_io(rdev, bb_sector, sectors << 9,
1566 				  rdev->bb_page, READ, true))
1567 			return -EIO;
1568 		bbp = (u64 *)page_address(rdev->bb_page);
1569 		rdev->badblocks.shift = sb->bblog_shift;
1570 		for (i = 0 ; i < (sectors << (9-3)) ; i++, bbp++) {
1571 			u64 bb = le64_to_cpu(*bbp);
1572 			int count = bb & (0x3ff);
1573 			u64 sector = bb >> 10;
1574 			sector <<= sb->bblog_shift;
1575 			count <<= sb->bblog_shift;
1576 			if (bb + 1 == 0)
1577 				break;
1578 			if (md_set_badblocks(&rdev->badblocks,
1579 					     sector, count, 1) == 0)
1580 				return -EINVAL;
1581 		}
1582 	} else if (sb->bblog_offset == 0)
1583 		rdev->badblocks.shift = -1;
1584 
1585 	if (!refdev) {
1586 		ret = 1;
1587 	} else {
1588 		__u64 ev1, ev2;
1589 		struct mdp_superblock_1 *refsb = page_address(refdev->sb_page);
1590 
1591 		if (memcmp(sb->set_uuid, refsb->set_uuid, 16) != 0 ||
1592 		    sb->level != refsb->level ||
1593 		    sb->layout != refsb->layout ||
1594 		    sb->chunksize != refsb->chunksize) {
1595 			printk(KERN_WARNING "md: %s has strangely different"
1596 				" superblock to %s\n",
1597 				bdevname(rdev->bdev,b),
1598 				bdevname(refdev->bdev,b2));
1599 			return -EINVAL;
1600 		}
1601 		ev1 = le64_to_cpu(sb->events);
1602 		ev2 = le64_to_cpu(refsb->events);
1603 
1604 		if (ev1 > ev2)
1605 			ret = 1;
1606 		else
1607 			ret = 0;
1608 	}
1609 	if (minor_version)
1610 		rdev->sectors = (i_size_read(rdev->bdev->bd_inode) >> 9) -
1611 			le64_to_cpu(sb->data_offset);
1612 	else
1613 		rdev->sectors = rdev->sb_start;
1614 	if (rdev->sectors < le64_to_cpu(sb->data_size))
1615 		return -EINVAL;
1616 	rdev->sectors = le64_to_cpu(sb->data_size);
1617 	if (le64_to_cpu(sb->size) > rdev->sectors)
1618 		return -EINVAL;
1619 	return ret;
1620 }
1621 
1622 static int super_1_validate(struct mddev *mddev, struct md_rdev *rdev)
1623 {
1624 	struct mdp_superblock_1 *sb = page_address(rdev->sb_page);
1625 	__u64 ev1 = le64_to_cpu(sb->events);
1626 
1627 	rdev->raid_disk = -1;
1628 	clear_bit(Faulty, &rdev->flags);
1629 	clear_bit(In_sync, &rdev->flags);
1630 	clear_bit(WriteMostly, &rdev->flags);
1631 
1632 	if (mddev->raid_disks == 0) {
1633 		mddev->major_version = 1;
1634 		mddev->patch_version = 0;
1635 		mddev->external = 0;
1636 		mddev->chunk_sectors = le32_to_cpu(sb->chunksize);
1637 		mddev->ctime = le64_to_cpu(sb->ctime) & ((1ULL << 32)-1);
1638 		mddev->utime = le64_to_cpu(sb->utime) & ((1ULL << 32)-1);
1639 		mddev->level = le32_to_cpu(sb->level);
1640 		mddev->clevel[0] = 0;
1641 		mddev->layout = le32_to_cpu(sb->layout);
1642 		mddev->raid_disks = le32_to_cpu(sb->raid_disks);
1643 		mddev->dev_sectors = le64_to_cpu(sb->size);
1644 		mddev->events = ev1;
1645 		mddev->bitmap_info.offset = 0;
1646 		mddev->bitmap_info.default_offset = 1024 >> 9;
1647 
1648 		mddev->recovery_cp = le64_to_cpu(sb->resync_offset);
1649 		memcpy(mddev->uuid, sb->set_uuid, 16);
1650 
1651 		mddev->max_disks =  (4096-256)/2;
1652 
1653 		if ((le32_to_cpu(sb->feature_map) & MD_FEATURE_BITMAP_OFFSET) &&
1654 		    mddev->bitmap_info.file == NULL )
1655 			mddev->bitmap_info.offset =
1656 				(__s32)le32_to_cpu(sb->bitmap_offset);
1657 
1658 		if ((le32_to_cpu(sb->feature_map) & MD_FEATURE_RESHAPE_ACTIVE)) {
1659 			mddev->reshape_position = le64_to_cpu(sb->reshape_position);
1660 			mddev->delta_disks = le32_to_cpu(sb->delta_disks);
1661 			mddev->new_level = le32_to_cpu(sb->new_level);
1662 			mddev->new_layout = le32_to_cpu(sb->new_layout);
1663 			mddev->new_chunk_sectors = le32_to_cpu(sb->new_chunk);
1664 		} else {
1665 			mddev->reshape_position = MaxSector;
1666 			mddev->delta_disks = 0;
1667 			mddev->new_level = mddev->level;
1668 			mddev->new_layout = mddev->layout;
1669 			mddev->new_chunk_sectors = mddev->chunk_sectors;
1670 		}
1671 
1672 	} else if (mddev->pers == NULL) {
1673 		/* Insist of good event counter while assembling, except for
1674 		 * spares (which don't need an event count) */
1675 		++ev1;
1676 		if (rdev->desc_nr >= 0 &&
1677 		    rdev->desc_nr < le32_to_cpu(sb->max_dev) &&
1678 		    le16_to_cpu(sb->dev_roles[rdev->desc_nr]) < 0xfffe)
1679 			if (ev1 < mddev->events)
1680 				return -EINVAL;
1681 	} else if (mddev->bitmap) {
1682 		/* If adding to array with a bitmap, then we can accept an
1683 		 * older device, but not too old.
1684 		 */
1685 		if (ev1 < mddev->bitmap->events_cleared)
1686 			return 0;
1687 	} else {
1688 		if (ev1 < mddev->events)
1689 			/* just a hot-add of a new device, leave raid_disk at -1 */
1690 			return 0;
1691 	}
1692 	if (mddev->level != LEVEL_MULTIPATH) {
1693 		int role;
1694 		if (rdev->desc_nr < 0 ||
1695 		    rdev->desc_nr >= le32_to_cpu(sb->max_dev)) {
1696 			role = 0xffff;
1697 			rdev->desc_nr = -1;
1698 		} else
1699 			role = le16_to_cpu(sb->dev_roles[rdev->desc_nr]);
1700 		switch(role) {
1701 		case 0xffff: /* spare */
1702 			break;
1703 		case 0xfffe: /* faulty */
1704 			set_bit(Faulty, &rdev->flags);
1705 			break;
1706 		default:
1707 			if ((le32_to_cpu(sb->feature_map) &
1708 			     MD_FEATURE_RECOVERY_OFFSET))
1709 				rdev->recovery_offset = le64_to_cpu(sb->recovery_offset);
1710 			else
1711 				set_bit(In_sync, &rdev->flags);
1712 			rdev->raid_disk = role;
1713 			break;
1714 		}
1715 		if (sb->devflags & WriteMostly1)
1716 			set_bit(WriteMostly, &rdev->flags);
1717 	} else /* MULTIPATH are always insync */
1718 		set_bit(In_sync, &rdev->flags);
1719 
1720 	return 0;
1721 }
1722 
1723 static void super_1_sync(struct mddev *mddev, struct md_rdev *rdev)
1724 {
1725 	struct mdp_superblock_1 *sb;
1726 	struct md_rdev *rdev2;
1727 	int max_dev, i;
1728 	/* make rdev->sb match mddev and rdev data. */
1729 
1730 	sb = page_address(rdev->sb_page);
1731 
1732 	sb->feature_map = 0;
1733 	sb->pad0 = 0;
1734 	sb->recovery_offset = cpu_to_le64(0);
1735 	memset(sb->pad1, 0, sizeof(sb->pad1));
1736 	memset(sb->pad3, 0, sizeof(sb->pad3));
1737 
1738 	sb->utime = cpu_to_le64((__u64)mddev->utime);
1739 	sb->events = cpu_to_le64(mddev->events);
1740 	if (mddev->in_sync)
1741 		sb->resync_offset = cpu_to_le64(mddev->recovery_cp);
1742 	else
1743 		sb->resync_offset = cpu_to_le64(0);
1744 
1745 	sb->cnt_corrected_read = cpu_to_le32(atomic_read(&rdev->corrected_errors));
1746 
1747 	sb->raid_disks = cpu_to_le32(mddev->raid_disks);
1748 	sb->size = cpu_to_le64(mddev->dev_sectors);
1749 	sb->chunksize = cpu_to_le32(mddev->chunk_sectors);
1750 	sb->level = cpu_to_le32(mddev->level);
1751 	sb->layout = cpu_to_le32(mddev->layout);
1752 
1753 	if (test_bit(WriteMostly, &rdev->flags))
1754 		sb->devflags |= WriteMostly1;
1755 	else
1756 		sb->devflags &= ~WriteMostly1;
1757 
1758 	if (mddev->bitmap && mddev->bitmap_info.file == NULL) {
1759 		sb->bitmap_offset = cpu_to_le32((__u32)mddev->bitmap_info.offset);
1760 		sb->feature_map = cpu_to_le32(MD_FEATURE_BITMAP_OFFSET);
1761 	}
1762 
1763 	if (rdev->raid_disk >= 0 &&
1764 	    !test_bit(In_sync, &rdev->flags)) {
1765 		sb->feature_map |=
1766 			cpu_to_le32(MD_FEATURE_RECOVERY_OFFSET);
1767 		sb->recovery_offset =
1768 			cpu_to_le64(rdev->recovery_offset);
1769 	}
1770 
1771 	if (mddev->reshape_position != MaxSector) {
1772 		sb->feature_map |= cpu_to_le32(MD_FEATURE_RESHAPE_ACTIVE);
1773 		sb->reshape_position = cpu_to_le64(mddev->reshape_position);
1774 		sb->new_layout = cpu_to_le32(mddev->new_layout);
1775 		sb->delta_disks = cpu_to_le32(mddev->delta_disks);
1776 		sb->new_level = cpu_to_le32(mddev->new_level);
1777 		sb->new_chunk = cpu_to_le32(mddev->new_chunk_sectors);
1778 	}
1779 
1780 	if (rdev->badblocks.count == 0)
1781 		/* Nothing to do for bad blocks*/ ;
1782 	else if (sb->bblog_offset == 0)
1783 		/* Cannot record bad blocks on this device */
1784 		md_error(mddev, rdev);
1785 	else {
1786 		struct badblocks *bb = &rdev->badblocks;
1787 		u64 *bbp = (u64 *)page_address(rdev->bb_page);
1788 		u64 *p = bb->page;
1789 		sb->feature_map |= cpu_to_le32(MD_FEATURE_BAD_BLOCKS);
1790 		if (bb->changed) {
1791 			unsigned seq;
1792 
1793 retry:
1794 			seq = read_seqbegin(&bb->lock);
1795 
1796 			memset(bbp, 0xff, PAGE_SIZE);
1797 
1798 			for (i = 0 ; i < bb->count ; i++) {
1799 				u64 internal_bb = *p++;
1800 				u64 store_bb = ((BB_OFFSET(internal_bb) << 10)
1801 						| BB_LEN(internal_bb));
1802 				*bbp++ = cpu_to_le64(store_bb);
1803 			}
1804 			if (read_seqretry(&bb->lock, seq))
1805 				goto retry;
1806 
1807 			bb->sector = (rdev->sb_start +
1808 				      (int)le32_to_cpu(sb->bblog_offset));
1809 			bb->size = le16_to_cpu(sb->bblog_size);
1810 			bb->changed = 0;
1811 		}
1812 	}
1813 
1814 	max_dev = 0;
1815 	list_for_each_entry(rdev2, &mddev->disks, same_set)
1816 		if (rdev2->desc_nr+1 > max_dev)
1817 			max_dev = rdev2->desc_nr+1;
1818 
1819 	if (max_dev > le32_to_cpu(sb->max_dev)) {
1820 		int bmask;
1821 		sb->max_dev = cpu_to_le32(max_dev);
1822 		rdev->sb_size = max_dev * 2 + 256;
1823 		bmask = queue_logical_block_size(rdev->bdev->bd_disk->queue)-1;
1824 		if (rdev->sb_size & bmask)
1825 			rdev->sb_size = (rdev->sb_size | bmask) + 1;
1826 	} else
1827 		max_dev = le32_to_cpu(sb->max_dev);
1828 
1829 	for (i=0; i<max_dev;i++)
1830 		sb->dev_roles[i] = cpu_to_le16(0xfffe);
1831 
1832 	list_for_each_entry(rdev2, &mddev->disks, same_set) {
1833 		i = rdev2->desc_nr;
1834 		if (test_bit(Faulty, &rdev2->flags))
1835 			sb->dev_roles[i] = cpu_to_le16(0xfffe);
1836 		else if (test_bit(In_sync, &rdev2->flags))
1837 			sb->dev_roles[i] = cpu_to_le16(rdev2->raid_disk);
1838 		else if (rdev2->raid_disk >= 0)
1839 			sb->dev_roles[i] = cpu_to_le16(rdev2->raid_disk);
1840 		else
1841 			sb->dev_roles[i] = cpu_to_le16(0xffff);
1842 	}
1843 
1844 	sb->sb_csum = calc_sb_1_csum(sb);
1845 }
1846 
1847 static unsigned long long
1848 super_1_rdev_size_change(struct md_rdev *rdev, sector_t num_sectors)
1849 {
1850 	struct mdp_superblock_1 *sb;
1851 	sector_t max_sectors;
1852 	if (num_sectors && num_sectors < rdev->mddev->dev_sectors)
1853 		return 0; /* component must fit device */
1854 	if (rdev->sb_start < rdev->data_offset) {
1855 		/* minor versions 1 and 2; superblock before data */
1856 		max_sectors = i_size_read(rdev->bdev->bd_inode) >> 9;
1857 		max_sectors -= rdev->data_offset;
1858 		if (!num_sectors || num_sectors > max_sectors)
1859 			num_sectors = max_sectors;
1860 	} else if (rdev->mddev->bitmap_info.offset) {
1861 		/* minor version 0 with bitmap we can't move */
1862 		return 0;
1863 	} else {
1864 		/* minor version 0; superblock after data */
1865 		sector_t sb_start;
1866 		sb_start = (i_size_read(rdev->bdev->bd_inode) >> 9) - 8*2;
1867 		sb_start &= ~(sector_t)(4*2 - 1);
1868 		max_sectors = rdev->sectors + sb_start - rdev->sb_start;
1869 		if (!num_sectors || num_sectors > max_sectors)
1870 			num_sectors = max_sectors;
1871 		rdev->sb_start = sb_start;
1872 	}
1873 	sb = page_address(rdev->sb_page);
1874 	sb->data_size = cpu_to_le64(num_sectors);
1875 	sb->super_offset = rdev->sb_start;
1876 	sb->sb_csum = calc_sb_1_csum(sb);
1877 	md_super_write(rdev->mddev, rdev, rdev->sb_start, rdev->sb_size,
1878 		       rdev->sb_page);
1879 	md_super_wait(rdev->mddev);
1880 	return num_sectors;
1881 }
1882 
1883 static struct super_type super_types[] = {
1884 	[0] = {
1885 		.name	= "0.90.0",
1886 		.owner	= THIS_MODULE,
1887 		.load_super	    = super_90_load,
1888 		.validate_super	    = super_90_validate,
1889 		.sync_super	    = super_90_sync,
1890 		.rdev_size_change   = super_90_rdev_size_change,
1891 	},
1892 	[1] = {
1893 		.name	= "md-1",
1894 		.owner	= THIS_MODULE,
1895 		.load_super	    = super_1_load,
1896 		.validate_super	    = super_1_validate,
1897 		.sync_super	    = super_1_sync,
1898 		.rdev_size_change   = super_1_rdev_size_change,
1899 	},
1900 };
1901 
1902 static void sync_super(struct mddev *mddev, struct md_rdev *rdev)
1903 {
1904 	if (mddev->sync_super) {
1905 		mddev->sync_super(mddev, rdev);
1906 		return;
1907 	}
1908 
1909 	BUG_ON(mddev->major_version >= ARRAY_SIZE(super_types));
1910 
1911 	super_types[mddev->major_version].sync_super(mddev, rdev);
1912 }
1913 
1914 static int match_mddev_units(struct mddev *mddev1, struct mddev *mddev2)
1915 {
1916 	struct md_rdev *rdev, *rdev2;
1917 
1918 	rcu_read_lock();
1919 	rdev_for_each_rcu(rdev, mddev1)
1920 		rdev_for_each_rcu(rdev2, mddev2)
1921 			if (rdev->bdev->bd_contains ==
1922 			    rdev2->bdev->bd_contains) {
1923 				rcu_read_unlock();
1924 				return 1;
1925 			}
1926 	rcu_read_unlock();
1927 	return 0;
1928 }
1929 
1930 static LIST_HEAD(pending_raid_disks);
1931 
1932 /*
1933  * Try to register data integrity profile for an mddev
1934  *
1935  * This is called when an array is started and after a disk has been kicked
1936  * from the array. It only succeeds if all working and active component devices
1937  * are integrity capable with matching profiles.
1938  */
1939 int md_integrity_register(struct mddev *mddev)
1940 {
1941 	struct md_rdev *rdev, *reference = NULL;
1942 
1943 	if (list_empty(&mddev->disks))
1944 		return 0; /* nothing to do */
1945 	if (!mddev->gendisk || blk_get_integrity(mddev->gendisk))
1946 		return 0; /* shouldn't register, or already is */
1947 	list_for_each_entry(rdev, &mddev->disks, same_set) {
1948 		/* skip spares and non-functional disks */
1949 		if (test_bit(Faulty, &rdev->flags))
1950 			continue;
1951 		if (rdev->raid_disk < 0)
1952 			continue;
1953 		if (!reference) {
1954 			/* Use the first rdev as the reference */
1955 			reference = rdev;
1956 			continue;
1957 		}
1958 		/* does this rdev's profile match the reference profile? */
1959 		if (blk_integrity_compare(reference->bdev->bd_disk,
1960 				rdev->bdev->bd_disk) < 0)
1961 			return -EINVAL;
1962 	}
1963 	if (!reference || !bdev_get_integrity(reference->bdev))
1964 		return 0;
1965 	/*
1966 	 * All component devices are integrity capable and have matching
1967 	 * profiles, register the common profile for the md device.
1968 	 */
1969 	if (blk_integrity_register(mddev->gendisk,
1970 			bdev_get_integrity(reference->bdev)) != 0) {
1971 		printk(KERN_ERR "md: failed to register integrity for %s\n",
1972 			mdname(mddev));
1973 		return -EINVAL;
1974 	}
1975 	printk(KERN_NOTICE "md: data integrity enabled on %s\n", mdname(mddev));
1976 	if (bioset_integrity_create(mddev->bio_set, BIO_POOL_SIZE)) {
1977 		printk(KERN_ERR "md: failed to create integrity pool for %s\n",
1978 		       mdname(mddev));
1979 		return -EINVAL;
1980 	}
1981 	return 0;
1982 }
1983 EXPORT_SYMBOL(md_integrity_register);
1984 
1985 /* Disable data integrity if non-capable/non-matching disk is being added */
1986 void md_integrity_add_rdev(struct md_rdev *rdev, struct mddev *mddev)
1987 {
1988 	struct blk_integrity *bi_rdev = bdev_get_integrity(rdev->bdev);
1989 	struct blk_integrity *bi_mddev = blk_get_integrity(mddev->gendisk);
1990 
1991 	if (!bi_mddev) /* nothing to do */
1992 		return;
1993 	if (rdev->raid_disk < 0) /* skip spares */
1994 		return;
1995 	if (bi_rdev && blk_integrity_compare(mddev->gendisk,
1996 					     rdev->bdev->bd_disk) >= 0)
1997 		return;
1998 	printk(KERN_NOTICE "disabling data integrity on %s\n", mdname(mddev));
1999 	blk_integrity_unregister(mddev->gendisk);
2000 }
2001 EXPORT_SYMBOL(md_integrity_add_rdev);
2002 
2003 static int bind_rdev_to_array(struct md_rdev * rdev, struct mddev * mddev)
2004 {
2005 	char b[BDEVNAME_SIZE];
2006 	struct kobject *ko;
2007 	char *s;
2008 	int err;
2009 
2010 	if (rdev->mddev) {
2011 		MD_BUG();
2012 		return -EINVAL;
2013 	}
2014 
2015 	/* prevent duplicates */
2016 	if (find_rdev(mddev, rdev->bdev->bd_dev))
2017 		return -EEXIST;
2018 
2019 	/* make sure rdev->sectors exceeds mddev->dev_sectors */
2020 	if (rdev->sectors && (mddev->dev_sectors == 0 ||
2021 			rdev->sectors < mddev->dev_sectors)) {
2022 		if (mddev->pers) {
2023 			/* Cannot change size, so fail
2024 			 * If mddev->level <= 0, then we don't care
2025 			 * about aligning sizes (e.g. linear)
2026 			 */
2027 			if (mddev->level > 0)
2028 				return -ENOSPC;
2029 		} else
2030 			mddev->dev_sectors = rdev->sectors;
2031 	}
2032 
2033 	/* Verify rdev->desc_nr is unique.
2034 	 * If it is -1, assign a free number, else
2035 	 * check number is not in use
2036 	 */
2037 	if (rdev->desc_nr < 0) {
2038 		int choice = 0;
2039 		if (mddev->pers) choice = mddev->raid_disks;
2040 		while (find_rdev_nr(mddev, choice))
2041 			choice++;
2042 		rdev->desc_nr = choice;
2043 	} else {
2044 		if (find_rdev_nr(mddev, rdev->desc_nr))
2045 			return -EBUSY;
2046 	}
2047 	if (mddev->max_disks && rdev->desc_nr >= mddev->max_disks) {
2048 		printk(KERN_WARNING "md: %s: array is limited to %d devices\n",
2049 		       mdname(mddev), mddev->max_disks);
2050 		return -EBUSY;
2051 	}
2052 	bdevname(rdev->bdev,b);
2053 	while ( (s=strchr(b, '/')) != NULL)
2054 		*s = '!';
2055 
2056 	rdev->mddev = mddev;
2057 	printk(KERN_INFO "md: bind<%s>\n", b);
2058 
2059 	if ((err = kobject_add(&rdev->kobj, &mddev->kobj, "dev-%s", b)))
2060 		goto fail;
2061 
2062 	ko = &part_to_dev(rdev->bdev->bd_part)->kobj;
2063 	if (sysfs_create_link(&rdev->kobj, ko, "block"))
2064 		/* failure here is OK */;
2065 	rdev->sysfs_state = sysfs_get_dirent_safe(rdev->kobj.sd, "state");
2066 
2067 	list_add_rcu(&rdev->same_set, &mddev->disks);
2068 	bd_link_disk_holder(rdev->bdev, mddev->gendisk);
2069 
2070 	/* May as well allow recovery to be retried once */
2071 	mddev->recovery_disabled++;
2072 
2073 	return 0;
2074 
2075  fail:
2076 	printk(KERN_WARNING "md: failed to register dev-%s for %s\n",
2077 	       b, mdname(mddev));
2078 	return err;
2079 }
2080 
2081 static void md_delayed_delete(struct work_struct *ws)
2082 {
2083 	struct md_rdev *rdev = container_of(ws, struct md_rdev, del_work);
2084 	kobject_del(&rdev->kobj);
2085 	kobject_put(&rdev->kobj);
2086 }
2087 
2088 static void unbind_rdev_from_array(struct md_rdev * rdev)
2089 {
2090 	char b[BDEVNAME_SIZE];
2091 	if (!rdev->mddev) {
2092 		MD_BUG();
2093 		return;
2094 	}
2095 	bd_unlink_disk_holder(rdev->bdev, rdev->mddev->gendisk);
2096 	list_del_rcu(&rdev->same_set);
2097 	printk(KERN_INFO "md: unbind<%s>\n", bdevname(rdev->bdev,b));
2098 	rdev->mddev = NULL;
2099 	sysfs_remove_link(&rdev->kobj, "block");
2100 	sysfs_put(rdev->sysfs_state);
2101 	rdev->sysfs_state = NULL;
2102 	kfree(rdev->badblocks.page);
2103 	rdev->badblocks.count = 0;
2104 	rdev->badblocks.page = NULL;
2105 	/* We need to delay this, otherwise we can deadlock when
2106 	 * writing to 'remove' to "dev/state".  We also need
2107 	 * to delay it due to rcu usage.
2108 	 */
2109 	synchronize_rcu();
2110 	INIT_WORK(&rdev->del_work, md_delayed_delete);
2111 	kobject_get(&rdev->kobj);
2112 	queue_work(md_misc_wq, &rdev->del_work);
2113 }
2114 
2115 /*
2116  * prevent the device from being mounted, repartitioned or
2117  * otherwise reused by a RAID array (or any other kernel
2118  * subsystem), by bd_claiming the device.
2119  */
2120 static int lock_rdev(struct md_rdev *rdev, dev_t dev, int shared)
2121 {
2122 	int err = 0;
2123 	struct block_device *bdev;
2124 	char b[BDEVNAME_SIZE];
2125 
2126 	bdev = blkdev_get_by_dev(dev, FMODE_READ|FMODE_WRITE|FMODE_EXCL,
2127 				 shared ? (struct md_rdev *)lock_rdev : rdev);
2128 	if (IS_ERR(bdev)) {
2129 		printk(KERN_ERR "md: could not open %s.\n",
2130 			__bdevname(dev, b));
2131 		return PTR_ERR(bdev);
2132 	}
2133 	rdev->bdev = bdev;
2134 	return err;
2135 }
2136 
2137 static void unlock_rdev(struct md_rdev *rdev)
2138 {
2139 	struct block_device *bdev = rdev->bdev;
2140 	rdev->bdev = NULL;
2141 	if (!bdev)
2142 		MD_BUG();
2143 	blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
2144 }
2145 
2146 void md_autodetect_dev(dev_t dev);
2147 
2148 static void export_rdev(struct md_rdev * rdev)
2149 {
2150 	char b[BDEVNAME_SIZE];
2151 	printk(KERN_INFO "md: export_rdev(%s)\n",
2152 		bdevname(rdev->bdev,b));
2153 	if (rdev->mddev)
2154 		MD_BUG();
2155 	free_disk_sb(rdev);
2156 #ifndef MODULE
2157 	if (test_bit(AutoDetected, &rdev->flags))
2158 		md_autodetect_dev(rdev->bdev->bd_dev);
2159 #endif
2160 	unlock_rdev(rdev);
2161 	kobject_put(&rdev->kobj);
2162 }
2163 
2164 static void kick_rdev_from_array(struct md_rdev * rdev)
2165 {
2166 	unbind_rdev_from_array(rdev);
2167 	export_rdev(rdev);
2168 }
2169 
2170 static void export_array(struct mddev *mddev)
2171 {
2172 	struct md_rdev *rdev, *tmp;
2173 
2174 	rdev_for_each(rdev, tmp, mddev) {
2175 		if (!rdev->mddev) {
2176 			MD_BUG();
2177 			continue;
2178 		}
2179 		kick_rdev_from_array(rdev);
2180 	}
2181 	if (!list_empty(&mddev->disks))
2182 		MD_BUG();
2183 	mddev->raid_disks = 0;
2184 	mddev->major_version = 0;
2185 }
2186 
2187 static void print_desc(mdp_disk_t *desc)
2188 {
2189 	printk(" DISK<N:%d,(%d,%d),R:%d,S:%d>\n", desc->number,
2190 		desc->major,desc->minor,desc->raid_disk,desc->state);
2191 }
2192 
2193 static void print_sb_90(mdp_super_t *sb)
2194 {
2195 	int i;
2196 
2197 	printk(KERN_INFO
2198 		"md:  SB: (V:%d.%d.%d) ID:<%08x.%08x.%08x.%08x> CT:%08x\n",
2199 		sb->major_version, sb->minor_version, sb->patch_version,
2200 		sb->set_uuid0, sb->set_uuid1, sb->set_uuid2, sb->set_uuid3,
2201 		sb->ctime);
2202 	printk(KERN_INFO "md:     L%d S%08d ND:%d RD:%d md%d LO:%d CS:%d\n",
2203 		sb->level, sb->size, sb->nr_disks, sb->raid_disks,
2204 		sb->md_minor, sb->layout, sb->chunk_size);
2205 	printk(KERN_INFO "md:     UT:%08x ST:%d AD:%d WD:%d"
2206 		" FD:%d SD:%d CSUM:%08x E:%08lx\n",
2207 		sb->utime, sb->state, sb->active_disks, sb->working_disks,
2208 		sb->failed_disks, sb->spare_disks,
2209 		sb->sb_csum, (unsigned long)sb->events_lo);
2210 
2211 	printk(KERN_INFO);
2212 	for (i = 0; i < MD_SB_DISKS; i++) {
2213 		mdp_disk_t *desc;
2214 
2215 		desc = sb->disks + i;
2216 		if (desc->number || desc->major || desc->minor ||
2217 		    desc->raid_disk || (desc->state && (desc->state != 4))) {
2218 			printk("     D %2d: ", i);
2219 			print_desc(desc);
2220 		}
2221 	}
2222 	printk(KERN_INFO "md:     THIS: ");
2223 	print_desc(&sb->this_disk);
2224 }
2225 
2226 static void print_sb_1(struct mdp_superblock_1 *sb)
2227 {
2228 	__u8 *uuid;
2229 
2230 	uuid = sb->set_uuid;
2231 	printk(KERN_INFO
2232 	       "md:  SB: (V:%u) (F:0x%08x) Array-ID:<%pU>\n"
2233 	       "md:    Name: \"%s\" CT:%llu\n",
2234 		le32_to_cpu(sb->major_version),
2235 		le32_to_cpu(sb->feature_map),
2236 		uuid,
2237 		sb->set_name,
2238 		(unsigned long long)le64_to_cpu(sb->ctime)
2239 		       & MD_SUPERBLOCK_1_TIME_SEC_MASK);
2240 
2241 	uuid = sb->device_uuid;
2242 	printk(KERN_INFO
2243 	       "md:       L%u SZ%llu RD:%u LO:%u CS:%u DO:%llu DS:%llu SO:%llu"
2244 			" RO:%llu\n"
2245 	       "md:     Dev:%08x UUID: %pU\n"
2246 	       "md:       (F:0x%08x) UT:%llu Events:%llu ResyncOffset:%llu CSUM:0x%08x\n"
2247 	       "md:         (MaxDev:%u) \n",
2248 		le32_to_cpu(sb->level),
2249 		(unsigned long long)le64_to_cpu(sb->size),
2250 		le32_to_cpu(sb->raid_disks),
2251 		le32_to_cpu(sb->layout),
2252 		le32_to_cpu(sb->chunksize),
2253 		(unsigned long long)le64_to_cpu(sb->data_offset),
2254 		(unsigned long long)le64_to_cpu(sb->data_size),
2255 		(unsigned long long)le64_to_cpu(sb->super_offset),
2256 		(unsigned long long)le64_to_cpu(sb->recovery_offset),
2257 		le32_to_cpu(sb->dev_number),
2258 		uuid,
2259 		sb->devflags,
2260 		(unsigned long long)le64_to_cpu(sb->utime) & MD_SUPERBLOCK_1_TIME_SEC_MASK,
2261 		(unsigned long long)le64_to_cpu(sb->events),
2262 		(unsigned long long)le64_to_cpu(sb->resync_offset),
2263 		le32_to_cpu(sb->sb_csum),
2264 		le32_to_cpu(sb->max_dev)
2265 		);
2266 }
2267 
2268 static void print_rdev(struct md_rdev *rdev, int major_version)
2269 {
2270 	char b[BDEVNAME_SIZE];
2271 	printk(KERN_INFO "md: rdev %s, Sect:%08llu F:%d S:%d DN:%u\n",
2272 		bdevname(rdev->bdev, b), (unsigned long long)rdev->sectors,
2273 	        test_bit(Faulty, &rdev->flags), test_bit(In_sync, &rdev->flags),
2274 	        rdev->desc_nr);
2275 	if (rdev->sb_loaded) {
2276 		printk(KERN_INFO "md: rdev superblock (MJ:%d):\n", major_version);
2277 		switch (major_version) {
2278 		case 0:
2279 			print_sb_90(page_address(rdev->sb_page));
2280 			break;
2281 		case 1:
2282 			print_sb_1(page_address(rdev->sb_page));
2283 			break;
2284 		}
2285 	} else
2286 		printk(KERN_INFO "md: no rdev superblock!\n");
2287 }
2288 
2289 static void md_print_devices(void)
2290 {
2291 	struct list_head *tmp;
2292 	struct md_rdev *rdev;
2293 	struct mddev *mddev;
2294 	char b[BDEVNAME_SIZE];
2295 
2296 	printk("\n");
2297 	printk("md:	**********************************\n");
2298 	printk("md:	* <COMPLETE RAID STATE PRINTOUT> *\n");
2299 	printk("md:	**********************************\n");
2300 	for_each_mddev(mddev, tmp) {
2301 
2302 		if (mddev->bitmap)
2303 			bitmap_print_sb(mddev->bitmap);
2304 		else
2305 			printk("%s: ", mdname(mddev));
2306 		list_for_each_entry(rdev, &mddev->disks, same_set)
2307 			printk("<%s>", bdevname(rdev->bdev,b));
2308 		printk("\n");
2309 
2310 		list_for_each_entry(rdev, &mddev->disks, same_set)
2311 			print_rdev(rdev, mddev->major_version);
2312 	}
2313 	printk("md:	**********************************\n");
2314 	printk("\n");
2315 }
2316 
2317 
2318 static void sync_sbs(struct mddev * mddev, int nospares)
2319 {
2320 	/* Update each superblock (in-memory image), but
2321 	 * if we are allowed to, skip spares which already
2322 	 * have the right event counter, or have one earlier
2323 	 * (which would mean they aren't being marked as dirty
2324 	 * with the rest of the array)
2325 	 */
2326 	struct md_rdev *rdev;
2327 	list_for_each_entry(rdev, &mddev->disks, same_set) {
2328 		if (rdev->sb_events == mddev->events ||
2329 		    (nospares &&
2330 		     rdev->raid_disk < 0 &&
2331 		     rdev->sb_events+1 == mddev->events)) {
2332 			/* Don't update this superblock */
2333 			rdev->sb_loaded = 2;
2334 		} else {
2335 			sync_super(mddev, rdev);
2336 			rdev->sb_loaded = 1;
2337 		}
2338 	}
2339 }
2340 
2341 static void md_update_sb(struct mddev * mddev, int force_change)
2342 {
2343 	struct md_rdev *rdev;
2344 	int sync_req;
2345 	int nospares = 0;
2346 	int any_badblocks_changed = 0;
2347 
2348 repeat:
2349 	/* First make sure individual recovery_offsets are correct */
2350 	list_for_each_entry(rdev, &mddev->disks, same_set) {
2351 		if (rdev->raid_disk >= 0 &&
2352 		    mddev->delta_disks >= 0 &&
2353 		    !test_bit(In_sync, &rdev->flags) &&
2354 		    mddev->curr_resync_completed > rdev->recovery_offset)
2355 				rdev->recovery_offset = mddev->curr_resync_completed;
2356 
2357 	}
2358 	if (!mddev->persistent) {
2359 		clear_bit(MD_CHANGE_CLEAN, &mddev->flags);
2360 		clear_bit(MD_CHANGE_DEVS, &mddev->flags);
2361 		if (!mddev->external) {
2362 			clear_bit(MD_CHANGE_PENDING, &mddev->flags);
2363 			list_for_each_entry(rdev, &mddev->disks, same_set) {
2364 				if (rdev->badblocks.changed) {
2365 					md_ack_all_badblocks(&rdev->badblocks);
2366 					md_error(mddev, rdev);
2367 				}
2368 				clear_bit(Blocked, &rdev->flags);
2369 				clear_bit(BlockedBadBlocks, &rdev->flags);
2370 				wake_up(&rdev->blocked_wait);
2371 			}
2372 		}
2373 		wake_up(&mddev->sb_wait);
2374 		return;
2375 	}
2376 
2377 	spin_lock_irq(&mddev->write_lock);
2378 
2379 	mddev->utime = get_seconds();
2380 
2381 	if (test_and_clear_bit(MD_CHANGE_DEVS, &mddev->flags))
2382 		force_change = 1;
2383 	if (test_and_clear_bit(MD_CHANGE_CLEAN, &mddev->flags))
2384 		/* just a clean<-> dirty transition, possibly leave spares alone,
2385 		 * though if events isn't the right even/odd, we will have to do
2386 		 * spares after all
2387 		 */
2388 		nospares = 1;
2389 	if (force_change)
2390 		nospares = 0;
2391 	if (mddev->degraded)
2392 		/* If the array is degraded, then skipping spares is both
2393 		 * dangerous and fairly pointless.
2394 		 * Dangerous because a device that was removed from the array
2395 		 * might have a event_count that still looks up-to-date,
2396 		 * so it can be re-added without a resync.
2397 		 * Pointless because if there are any spares to skip,
2398 		 * then a recovery will happen and soon that array won't
2399 		 * be degraded any more and the spare can go back to sleep then.
2400 		 */
2401 		nospares = 0;
2402 
2403 	sync_req = mddev->in_sync;
2404 
2405 	/* If this is just a dirty<->clean transition, and the array is clean
2406 	 * and 'events' is odd, we can roll back to the previous clean state */
2407 	if (nospares
2408 	    && (mddev->in_sync && mddev->recovery_cp == MaxSector)
2409 	    && mddev->can_decrease_events
2410 	    && mddev->events != 1) {
2411 		mddev->events--;
2412 		mddev->can_decrease_events = 0;
2413 	} else {
2414 		/* otherwise we have to go forward and ... */
2415 		mddev->events ++;
2416 		mddev->can_decrease_events = nospares;
2417 	}
2418 
2419 	if (!mddev->events) {
2420 		/*
2421 		 * oops, this 64-bit counter should never wrap.
2422 		 * Either we are in around ~1 trillion A.C., assuming
2423 		 * 1 reboot per second, or we have a bug:
2424 		 */
2425 		MD_BUG();
2426 		mddev->events --;
2427 	}
2428 
2429 	list_for_each_entry(rdev, &mddev->disks, same_set) {
2430 		if (rdev->badblocks.changed)
2431 			any_badblocks_changed++;
2432 		if (test_bit(Faulty, &rdev->flags))
2433 			set_bit(FaultRecorded, &rdev->flags);
2434 	}
2435 
2436 	sync_sbs(mddev, nospares);
2437 	spin_unlock_irq(&mddev->write_lock);
2438 
2439 	pr_debug("md: updating %s RAID superblock on device (in sync %d)\n",
2440 		 mdname(mddev), mddev->in_sync);
2441 
2442 	bitmap_update_sb(mddev->bitmap);
2443 	list_for_each_entry(rdev, &mddev->disks, same_set) {
2444 		char b[BDEVNAME_SIZE];
2445 
2446 		if (rdev->sb_loaded != 1)
2447 			continue; /* no noise on spare devices */
2448 
2449 		if (!test_bit(Faulty, &rdev->flags) &&
2450 		    rdev->saved_raid_disk == -1) {
2451 			md_super_write(mddev,rdev,
2452 				       rdev->sb_start, rdev->sb_size,
2453 				       rdev->sb_page);
2454 			pr_debug("md: (write) %s's sb offset: %llu\n",
2455 				 bdevname(rdev->bdev, b),
2456 				 (unsigned long long)rdev->sb_start);
2457 			rdev->sb_events = mddev->events;
2458 			if (rdev->badblocks.size) {
2459 				md_super_write(mddev, rdev,
2460 					       rdev->badblocks.sector,
2461 					       rdev->badblocks.size << 9,
2462 					       rdev->bb_page);
2463 				rdev->badblocks.size = 0;
2464 			}
2465 
2466 		} else if (test_bit(Faulty, &rdev->flags))
2467 			pr_debug("md: %s (skipping faulty)\n",
2468 				 bdevname(rdev->bdev, b));
2469 		else
2470 			pr_debug("(skipping incremental s/r ");
2471 
2472 		if (mddev->level == LEVEL_MULTIPATH)
2473 			/* only need to write one superblock... */
2474 			break;
2475 	}
2476 	md_super_wait(mddev);
2477 	/* if there was a failure, MD_CHANGE_DEVS was set, and we re-write super */
2478 
2479 	spin_lock_irq(&mddev->write_lock);
2480 	if (mddev->in_sync != sync_req ||
2481 	    test_bit(MD_CHANGE_DEVS, &mddev->flags)) {
2482 		/* have to write it out again */
2483 		spin_unlock_irq(&mddev->write_lock);
2484 		goto repeat;
2485 	}
2486 	clear_bit(MD_CHANGE_PENDING, &mddev->flags);
2487 	spin_unlock_irq(&mddev->write_lock);
2488 	wake_up(&mddev->sb_wait);
2489 	if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
2490 		sysfs_notify(&mddev->kobj, NULL, "sync_completed");
2491 
2492 	list_for_each_entry(rdev, &mddev->disks, same_set) {
2493 		if (test_and_clear_bit(FaultRecorded, &rdev->flags))
2494 			clear_bit(Blocked, &rdev->flags);
2495 
2496 		if (any_badblocks_changed)
2497 			md_ack_all_badblocks(&rdev->badblocks);
2498 		clear_bit(BlockedBadBlocks, &rdev->flags);
2499 		wake_up(&rdev->blocked_wait);
2500 	}
2501 }
2502 
2503 /* words written to sysfs files may, or may not, be \n terminated.
2504  * We want to accept with case. For this we use cmd_match.
2505  */
2506 static int cmd_match(const char *cmd, const char *str)
2507 {
2508 	/* See if cmd, written into a sysfs file, matches
2509 	 * str.  They must either be the same, or cmd can
2510 	 * have a trailing newline
2511 	 */
2512 	while (*cmd && *str && *cmd == *str) {
2513 		cmd++;
2514 		str++;
2515 	}
2516 	if (*cmd == '\n')
2517 		cmd++;
2518 	if (*str || *cmd)
2519 		return 0;
2520 	return 1;
2521 }
2522 
2523 struct rdev_sysfs_entry {
2524 	struct attribute attr;
2525 	ssize_t (*show)(struct md_rdev *, char *);
2526 	ssize_t (*store)(struct md_rdev *, const char *, size_t);
2527 };
2528 
2529 static ssize_t
2530 state_show(struct md_rdev *rdev, char *page)
2531 {
2532 	char *sep = "";
2533 	size_t len = 0;
2534 
2535 	if (test_bit(Faulty, &rdev->flags) ||
2536 	    rdev->badblocks.unacked_exist) {
2537 		len+= sprintf(page+len, "%sfaulty",sep);
2538 		sep = ",";
2539 	}
2540 	if (test_bit(In_sync, &rdev->flags)) {
2541 		len += sprintf(page+len, "%sin_sync",sep);
2542 		sep = ",";
2543 	}
2544 	if (test_bit(WriteMostly, &rdev->flags)) {
2545 		len += sprintf(page+len, "%swrite_mostly",sep);
2546 		sep = ",";
2547 	}
2548 	if (test_bit(Blocked, &rdev->flags) ||
2549 	    (rdev->badblocks.unacked_exist
2550 	     && !test_bit(Faulty, &rdev->flags))) {
2551 		len += sprintf(page+len, "%sblocked", sep);
2552 		sep = ",";
2553 	}
2554 	if (!test_bit(Faulty, &rdev->flags) &&
2555 	    !test_bit(In_sync, &rdev->flags)) {
2556 		len += sprintf(page+len, "%sspare", sep);
2557 		sep = ",";
2558 	}
2559 	if (test_bit(WriteErrorSeen, &rdev->flags)) {
2560 		len += sprintf(page+len, "%swrite_error", sep);
2561 		sep = ",";
2562 	}
2563 	return len+sprintf(page+len, "\n");
2564 }
2565 
2566 static ssize_t
2567 state_store(struct md_rdev *rdev, const char *buf, size_t len)
2568 {
2569 	/* can write
2570 	 *  faulty  - simulates an error
2571 	 *  remove  - disconnects the device
2572 	 *  writemostly - sets write_mostly
2573 	 *  -writemostly - clears write_mostly
2574 	 *  blocked - sets the Blocked flags
2575 	 *  -blocked - clears the Blocked and possibly simulates an error
2576 	 *  insync - sets Insync providing device isn't active
2577 	 *  write_error - sets WriteErrorSeen
2578 	 *  -write_error - clears WriteErrorSeen
2579 	 */
2580 	int err = -EINVAL;
2581 	if (cmd_match(buf, "faulty") && rdev->mddev->pers) {
2582 		md_error(rdev->mddev, rdev);
2583 		if (test_bit(Faulty, &rdev->flags))
2584 			err = 0;
2585 		else
2586 			err = -EBUSY;
2587 	} else if (cmd_match(buf, "remove")) {
2588 		if (rdev->raid_disk >= 0)
2589 			err = -EBUSY;
2590 		else {
2591 			struct mddev *mddev = rdev->mddev;
2592 			kick_rdev_from_array(rdev);
2593 			if (mddev->pers)
2594 				md_update_sb(mddev, 1);
2595 			md_new_event(mddev);
2596 			err = 0;
2597 		}
2598 	} else if (cmd_match(buf, "writemostly")) {
2599 		set_bit(WriteMostly, &rdev->flags);
2600 		err = 0;
2601 	} else if (cmd_match(buf, "-writemostly")) {
2602 		clear_bit(WriteMostly, &rdev->flags);
2603 		err = 0;
2604 	} else if (cmd_match(buf, "blocked")) {
2605 		set_bit(Blocked, &rdev->flags);
2606 		err = 0;
2607 	} else if (cmd_match(buf, "-blocked")) {
2608 		if (!test_bit(Faulty, &rdev->flags) &&
2609 		    rdev->badblocks.unacked_exist) {
2610 			/* metadata handler doesn't understand badblocks,
2611 			 * so we need to fail the device
2612 			 */
2613 			md_error(rdev->mddev, rdev);
2614 		}
2615 		clear_bit(Blocked, &rdev->flags);
2616 		clear_bit(BlockedBadBlocks, &rdev->flags);
2617 		wake_up(&rdev->blocked_wait);
2618 		set_bit(MD_RECOVERY_NEEDED, &rdev->mddev->recovery);
2619 		md_wakeup_thread(rdev->mddev->thread);
2620 
2621 		err = 0;
2622 	} else if (cmd_match(buf, "insync") && rdev->raid_disk == -1) {
2623 		set_bit(In_sync, &rdev->flags);
2624 		err = 0;
2625 	} else if (cmd_match(buf, "write_error")) {
2626 		set_bit(WriteErrorSeen, &rdev->flags);
2627 		err = 0;
2628 	} else if (cmd_match(buf, "-write_error")) {
2629 		clear_bit(WriteErrorSeen, &rdev->flags);
2630 		err = 0;
2631 	}
2632 	if (!err)
2633 		sysfs_notify_dirent_safe(rdev->sysfs_state);
2634 	return err ? err : len;
2635 }
2636 static struct rdev_sysfs_entry rdev_state =
2637 __ATTR(state, S_IRUGO|S_IWUSR, state_show, state_store);
2638 
2639 static ssize_t
2640 errors_show(struct md_rdev *rdev, char *page)
2641 {
2642 	return sprintf(page, "%d\n", atomic_read(&rdev->corrected_errors));
2643 }
2644 
2645 static ssize_t
2646 errors_store(struct md_rdev *rdev, const char *buf, size_t len)
2647 {
2648 	char *e;
2649 	unsigned long n = simple_strtoul(buf, &e, 10);
2650 	if (*buf && (*e == 0 || *e == '\n')) {
2651 		atomic_set(&rdev->corrected_errors, n);
2652 		return len;
2653 	}
2654 	return -EINVAL;
2655 }
2656 static struct rdev_sysfs_entry rdev_errors =
2657 __ATTR(errors, S_IRUGO|S_IWUSR, errors_show, errors_store);
2658 
2659 static ssize_t
2660 slot_show(struct md_rdev *rdev, char *page)
2661 {
2662 	if (rdev->raid_disk < 0)
2663 		return sprintf(page, "none\n");
2664 	else
2665 		return sprintf(page, "%d\n", rdev->raid_disk);
2666 }
2667 
2668 static ssize_t
2669 slot_store(struct md_rdev *rdev, const char *buf, size_t len)
2670 {
2671 	char *e;
2672 	int err;
2673 	int slot = simple_strtoul(buf, &e, 10);
2674 	if (strncmp(buf, "none", 4)==0)
2675 		slot = -1;
2676 	else if (e==buf || (*e && *e!= '\n'))
2677 		return -EINVAL;
2678 	if (rdev->mddev->pers && slot == -1) {
2679 		/* Setting 'slot' on an active array requires also
2680 		 * updating the 'rd%d' link, and communicating
2681 		 * with the personality with ->hot_*_disk.
2682 		 * For now we only support removing
2683 		 * failed/spare devices.  This normally happens automatically,
2684 		 * but not when the metadata is externally managed.
2685 		 */
2686 		if (rdev->raid_disk == -1)
2687 			return -EEXIST;
2688 		/* personality does all needed checks */
2689 		if (rdev->mddev->pers->hot_remove_disk == NULL)
2690 			return -EINVAL;
2691 		err = rdev->mddev->pers->
2692 			hot_remove_disk(rdev->mddev, rdev->raid_disk);
2693 		if (err)
2694 			return err;
2695 		sysfs_unlink_rdev(rdev->mddev, rdev);
2696 		rdev->raid_disk = -1;
2697 		set_bit(MD_RECOVERY_NEEDED, &rdev->mddev->recovery);
2698 		md_wakeup_thread(rdev->mddev->thread);
2699 	} else if (rdev->mddev->pers) {
2700 		struct md_rdev *rdev2;
2701 		/* Activating a spare .. or possibly reactivating
2702 		 * if we ever get bitmaps working here.
2703 		 */
2704 
2705 		if (rdev->raid_disk != -1)
2706 			return -EBUSY;
2707 
2708 		if (test_bit(MD_RECOVERY_RUNNING, &rdev->mddev->recovery))
2709 			return -EBUSY;
2710 
2711 		if (rdev->mddev->pers->hot_add_disk == NULL)
2712 			return -EINVAL;
2713 
2714 		list_for_each_entry(rdev2, &rdev->mddev->disks, same_set)
2715 			if (rdev2->raid_disk == slot)
2716 				return -EEXIST;
2717 
2718 		if (slot >= rdev->mddev->raid_disks &&
2719 		    slot >= rdev->mddev->raid_disks + rdev->mddev->delta_disks)
2720 			return -ENOSPC;
2721 
2722 		rdev->raid_disk = slot;
2723 		if (test_bit(In_sync, &rdev->flags))
2724 			rdev->saved_raid_disk = slot;
2725 		else
2726 			rdev->saved_raid_disk = -1;
2727 		clear_bit(In_sync, &rdev->flags);
2728 		err = rdev->mddev->pers->
2729 			hot_add_disk(rdev->mddev, rdev);
2730 		if (err) {
2731 			rdev->raid_disk = -1;
2732 			return err;
2733 		} else
2734 			sysfs_notify_dirent_safe(rdev->sysfs_state);
2735 		if (sysfs_link_rdev(rdev->mddev, rdev))
2736 			/* failure here is OK */;
2737 		/* don't wakeup anyone, leave that to userspace. */
2738 	} else {
2739 		if (slot >= rdev->mddev->raid_disks &&
2740 		    slot >= rdev->mddev->raid_disks + rdev->mddev->delta_disks)
2741 			return -ENOSPC;
2742 		rdev->raid_disk = slot;
2743 		/* assume it is working */
2744 		clear_bit(Faulty, &rdev->flags);
2745 		clear_bit(WriteMostly, &rdev->flags);
2746 		set_bit(In_sync, &rdev->flags);
2747 		sysfs_notify_dirent_safe(rdev->sysfs_state);
2748 	}
2749 	return len;
2750 }
2751 
2752 
2753 static struct rdev_sysfs_entry rdev_slot =
2754 __ATTR(slot, S_IRUGO|S_IWUSR, slot_show, slot_store);
2755 
2756 static ssize_t
2757 offset_show(struct md_rdev *rdev, char *page)
2758 {
2759 	return sprintf(page, "%llu\n", (unsigned long long)rdev->data_offset);
2760 }
2761 
2762 static ssize_t
2763 offset_store(struct md_rdev *rdev, const char *buf, size_t len)
2764 {
2765 	char *e;
2766 	unsigned long long offset = simple_strtoull(buf, &e, 10);
2767 	if (e==buf || (*e && *e != '\n'))
2768 		return -EINVAL;
2769 	if (rdev->mddev->pers && rdev->raid_disk >= 0)
2770 		return -EBUSY;
2771 	if (rdev->sectors && rdev->mddev->external)
2772 		/* Must set offset before size, so overlap checks
2773 		 * can be sane */
2774 		return -EBUSY;
2775 	rdev->data_offset = offset;
2776 	return len;
2777 }
2778 
2779 static struct rdev_sysfs_entry rdev_offset =
2780 __ATTR(offset, S_IRUGO|S_IWUSR, offset_show, offset_store);
2781 
2782 static ssize_t
2783 rdev_size_show(struct md_rdev *rdev, char *page)
2784 {
2785 	return sprintf(page, "%llu\n", (unsigned long long)rdev->sectors / 2);
2786 }
2787 
2788 static int overlaps(sector_t s1, sector_t l1, sector_t s2, sector_t l2)
2789 {
2790 	/* check if two start/length pairs overlap */
2791 	if (s1+l1 <= s2)
2792 		return 0;
2793 	if (s2+l2 <= s1)
2794 		return 0;
2795 	return 1;
2796 }
2797 
2798 static int strict_blocks_to_sectors(const char *buf, sector_t *sectors)
2799 {
2800 	unsigned long long blocks;
2801 	sector_t new;
2802 
2803 	if (strict_strtoull(buf, 10, &blocks) < 0)
2804 		return -EINVAL;
2805 
2806 	if (blocks & 1ULL << (8 * sizeof(blocks) - 1))
2807 		return -EINVAL; /* sector conversion overflow */
2808 
2809 	new = blocks * 2;
2810 	if (new != blocks * 2)
2811 		return -EINVAL; /* unsigned long long to sector_t overflow */
2812 
2813 	*sectors = new;
2814 	return 0;
2815 }
2816 
2817 static ssize_t
2818 rdev_size_store(struct md_rdev *rdev, const char *buf, size_t len)
2819 {
2820 	struct mddev *my_mddev = rdev->mddev;
2821 	sector_t oldsectors = rdev->sectors;
2822 	sector_t sectors;
2823 
2824 	if (strict_blocks_to_sectors(buf, &sectors) < 0)
2825 		return -EINVAL;
2826 	if (my_mddev->pers && rdev->raid_disk >= 0) {
2827 		if (my_mddev->persistent) {
2828 			sectors = super_types[my_mddev->major_version].
2829 				rdev_size_change(rdev, sectors);
2830 			if (!sectors)
2831 				return -EBUSY;
2832 		} else if (!sectors)
2833 			sectors = (i_size_read(rdev->bdev->bd_inode) >> 9) -
2834 				rdev->data_offset;
2835 	}
2836 	if (sectors < my_mddev->dev_sectors)
2837 		return -EINVAL; /* component must fit device */
2838 
2839 	rdev->sectors = sectors;
2840 	if (sectors > oldsectors && my_mddev->external) {
2841 		/* need to check that all other rdevs with the same ->bdev
2842 		 * do not overlap.  We need to unlock the mddev to avoid
2843 		 * a deadlock.  We have already changed rdev->sectors, and if
2844 		 * we have to change it back, we will have the lock again.
2845 		 */
2846 		struct mddev *mddev;
2847 		int overlap = 0;
2848 		struct list_head *tmp;
2849 
2850 		mddev_unlock(my_mddev);
2851 		for_each_mddev(mddev, tmp) {
2852 			struct md_rdev *rdev2;
2853 
2854 			mddev_lock(mddev);
2855 			list_for_each_entry(rdev2, &mddev->disks, same_set)
2856 				if (rdev->bdev == rdev2->bdev &&
2857 				    rdev != rdev2 &&
2858 				    overlaps(rdev->data_offset, rdev->sectors,
2859 					     rdev2->data_offset,
2860 					     rdev2->sectors)) {
2861 					overlap = 1;
2862 					break;
2863 				}
2864 			mddev_unlock(mddev);
2865 			if (overlap) {
2866 				mddev_put(mddev);
2867 				break;
2868 			}
2869 		}
2870 		mddev_lock(my_mddev);
2871 		if (overlap) {
2872 			/* Someone else could have slipped in a size
2873 			 * change here, but doing so is just silly.
2874 			 * We put oldsectors back because we *know* it is
2875 			 * safe, and trust userspace not to race with
2876 			 * itself
2877 			 */
2878 			rdev->sectors = oldsectors;
2879 			return -EBUSY;
2880 		}
2881 	}
2882 	return len;
2883 }
2884 
2885 static struct rdev_sysfs_entry rdev_size =
2886 __ATTR(size, S_IRUGO|S_IWUSR, rdev_size_show, rdev_size_store);
2887 
2888 
2889 static ssize_t recovery_start_show(struct md_rdev *rdev, char *page)
2890 {
2891 	unsigned long long recovery_start = rdev->recovery_offset;
2892 
2893 	if (test_bit(In_sync, &rdev->flags) ||
2894 	    recovery_start == MaxSector)
2895 		return sprintf(page, "none\n");
2896 
2897 	return sprintf(page, "%llu\n", recovery_start);
2898 }
2899 
2900 static ssize_t recovery_start_store(struct md_rdev *rdev, const char *buf, size_t len)
2901 {
2902 	unsigned long long recovery_start;
2903 
2904 	if (cmd_match(buf, "none"))
2905 		recovery_start = MaxSector;
2906 	else if (strict_strtoull(buf, 10, &recovery_start))
2907 		return -EINVAL;
2908 
2909 	if (rdev->mddev->pers &&
2910 	    rdev->raid_disk >= 0)
2911 		return -EBUSY;
2912 
2913 	rdev->recovery_offset = recovery_start;
2914 	if (recovery_start == MaxSector)
2915 		set_bit(In_sync, &rdev->flags);
2916 	else
2917 		clear_bit(In_sync, &rdev->flags);
2918 	return len;
2919 }
2920 
2921 static struct rdev_sysfs_entry rdev_recovery_start =
2922 __ATTR(recovery_start, S_IRUGO|S_IWUSR, recovery_start_show, recovery_start_store);
2923 
2924 
2925 static ssize_t
2926 badblocks_show(struct badblocks *bb, char *page, int unack);
2927 static ssize_t
2928 badblocks_store(struct badblocks *bb, const char *page, size_t len, int unack);
2929 
2930 static ssize_t bb_show(struct md_rdev *rdev, char *page)
2931 {
2932 	return badblocks_show(&rdev->badblocks, page, 0);
2933 }
2934 static ssize_t bb_store(struct md_rdev *rdev, const char *page, size_t len)
2935 {
2936 	int rv = badblocks_store(&rdev->badblocks, page, len, 0);
2937 	/* Maybe that ack was all we needed */
2938 	if (test_and_clear_bit(BlockedBadBlocks, &rdev->flags))
2939 		wake_up(&rdev->blocked_wait);
2940 	return rv;
2941 }
2942 static struct rdev_sysfs_entry rdev_bad_blocks =
2943 __ATTR(bad_blocks, S_IRUGO|S_IWUSR, bb_show, bb_store);
2944 
2945 
2946 static ssize_t ubb_show(struct md_rdev *rdev, char *page)
2947 {
2948 	return badblocks_show(&rdev->badblocks, page, 1);
2949 }
2950 static ssize_t ubb_store(struct md_rdev *rdev, const char *page, size_t len)
2951 {
2952 	return badblocks_store(&rdev->badblocks, page, len, 1);
2953 }
2954 static struct rdev_sysfs_entry rdev_unack_bad_blocks =
2955 __ATTR(unacknowledged_bad_blocks, S_IRUGO|S_IWUSR, ubb_show, ubb_store);
2956 
2957 static struct attribute *rdev_default_attrs[] = {
2958 	&rdev_state.attr,
2959 	&rdev_errors.attr,
2960 	&rdev_slot.attr,
2961 	&rdev_offset.attr,
2962 	&rdev_size.attr,
2963 	&rdev_recovery_start.attr,
2964 	&rdev_bad_blocks.attr,
2965 	&rdev_unack_bad_blocks.attr,
2966 	NULL,
2967 };
2968 static ssize_t
2969 rdev_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
2970 {
2971 	struct rdev_sysfs_entry *entry = container_of(attr, struct rdev_sysfs_entry, attr);
2972 	struct md_rdev *rdev = container_of(kobj, struct md_rdev, kobj);
2973 	struct mddev *mddev = rdev->mddev;
2974 	ssize_t rv;
2975 
2976 	if (!entry->show)
2977 		return -EIO;
2978 
2979 	rv = mddev ? mddev_lock(mddev) : -EBUSY;
2980 	if (!rv) {
2981 		if (rdev->mddev == NULL)
2982 			rv = -EBUSY;
2983 		else
2984 			rv = entry->show(rdev, page);
2985 		mddev_unlock(mddev);
2986 	}
2987 	return rv;
2988 }
2989 
2990 static ssize_t
2991 rdev_attr_store(struct kobject *kobj, struct attribute *attr,
2992 	      const char *page, size_t length)
2993 {
2994 	struct rdev_sysfs_entry *entry = container_of(attr, struct rdev_sysfs_entry, attr);
2995 	struct md_rdev *rdev = container_of(kobj, struct md_rdev, kobj);
2996 	ssize_t rv;
2997 	struct mddev *mddev = rdev->mddev;
2998 
2999 	if (!entry->store)
3000 		return -EIO;
3001 	if (!capable(CAP_SYS_ADMIN))
3002 		return -EACCES;
3003 	rv = mddev ? mddev_lock(mddev): -EBUSY;
3004 	if (!rv) {
3005 		if (rdev->mddev == NULL)
3006 			rv = -EBUSY;
3007 		else
3008 			rv = entry->store(rdev, page, length);
3009 		mddev_unlock(mddev);
3010 	}
3011 	return rv;
3012 }
3013 
3014 static void rdev_free(struct kobject *ko)
3015 {
3016 	struct md_rdev *rdev = container_of(ko, struct md_rdev, kobj);
3017 	kfree(rdev);
3018 }
3019 static const struct sysfs_ops rdev_sysfs_ops = {
3020 	.show		= rdev_attr_show,
3021 	.store		= rdev_attr_store,
3022 };
3023 static struct kobj_type rdev_ktype = {
3024 	.release	= rdev_free,
3025 	.sysfs_ops	= &rdev_sysfs_ops,
3026 	.default_attrs	= rdev_default_attrs,
3027 };
3028 
3029 int md_rdev_init(struct md_rdev *rdev)
3030 {
3031 	rdev->desc_nr = -1;
3032 	rdev->saved_raid_disk = -1;
3033 	rdev->raid_disk = -1;
3034 	rdev->flags = 0;
3035 	rdev->data_offset = 0;
3036 	rdev->sb_events = 0;
3037 	rdev->last_read_error.tv_sec  = 0;
3038 	rdev->last_read_error.tv_nsec = 0;
3039 	rdev->sb_loaded = 0;
3040 	rdev->bb_page = NULL;
3041 	atomic_set(&rdev->nr_pending, 0);
3042 	atomic_set(&rdev->read_errors, 0);
3043 	atomic_set(&rdev->corrected_errors, 0);
3044 
3045 	INIT_LIST_HEAD(&rdev->same_set);
3046 	init_waitqueue_head(&rdev->blocked_wait);
3047 
3048 	/* Add space to store bad block list.
3049 	 * This reserves the space even on arrays where it cannot
3050 	 * be used - I wonder if that matters
3051 	 */
3052 	rdev->badblocks.count = 0;
3053 	rdev->badblocks.shift = 0;
3054 	rdev->badblocks.page = kmalloc(PAGE_SIZE, GFP_KERNEL);
3055 	seqlock_init(&rdev->badblocks.lock);
3056 	if (rdev->badblocks.page == NULL)
3057 		return -ENOMEM;
3058 
3059 	return 0;
3060 }
3061 EXPORT_SYMBOL_GPL(md_rdev_init);
3062 /*
3063  * Import a device. If 'super_format' >= 0, then sanity check the superblock
3064  *
3065  * mark the device faulty if:
3066  *
3067  *   - the device is nonexistent (zero size)
3068  *   - the device has no valid superblock
3069  *
3070  * a faulty rdev _never_ has rdev->sb set.
3071  */
3072 static struct md_rdev *md_import_device(dev_t newdev, int super_format, int super_minor)
3073 {
3074 	char b[BDEVNAME_SIZE];
3075 	int err;
3076 	struct md_rdev *rdev;
3077 	sector_t size;
3078 
3079 	rdev = kzalloc(sizeof(*rdev), GFP_KERNEL);
3080 	if (!rdev) {
3081 		printk(KERN_ERR "md: could not alloc mem for new device!\n");
3082 		return ERR_PTR(-ENOMEM);
3083 	}
3084 
3085 	err = md_rdev_init(rdev);
3086 	if (err)
3087 		goto abort_free;
3088 	err = alloc_disk_sb(rdev);
3089 	if (err)
3090 		goto abort_free;
3091 
3092 	err = lock_rdev(rdev, newdev, super_format == -2);
3093 	if (err)
3094 		goto abort_free;
3095 
3096 	kobject_init(&rdev->kobj, &rdev_ktype);
3097 
3098 	size = i_size_read(rdev->bdev->bd_inode) >> BLOCK_SIZE_BITS;
3099 	if (!size) {
3100 		printk(KERN_WARNING
3101 			"md: %s has zero or unknown size, marking faulty!\n",
3102 			bdevname(rdev->bdev,b));
3103 		err = -EINVAL;
3104 		goto abort_free;
3105 	}
3106 
3107 	if (super_format >= 0) {
3108 		err = super_types[super_format].
3109 			load_super(rdev, NULL, super_minor);
3110 		if (err == -EINVAL) {
3111 			printk(KERN_WARNING
3112 				"md: %s does not have a valid v%d.%d "
3113 			       "superblock, not importing!\n",
3114 				bdevname(rdev->bdev,b),
3115 			       super_format, super_minor);
3116 			goto abort_free;
3117 		}
3118 		if (err < 0) {
3119 			printk(KERN_WARNING
3120 				"md: could not read %s's sb, not importing!\n",
3121 				bdevname(rdev->bdev,b));
3122 			goto abort_free;
3123 		}
3124 	}
3125 	if (super_format == -1)
3126 		/* hot-add for 0.90, or non-persistent: so no badblocks */
3127 		rdev->badblocks.shift = -1;
3128 
3129 	return rdev;
3130 
3131 abort_free:
3132 	if (rdev->bdev)
3133 		unlock_rdev(rdev);
3134 	free_disk_sb(rdev);
3135 	kfree(rdev->badblocks.page);
3136 	kfree(rdev);
3137 	return ERR_PTR(err);
3138 }
3139 
3140 /*
3141  * Check a full RAID array for plausibility
3142  */
3143 
3144 
3145 static void analyze_sbs(struct mddev * mddev)
3146 {
3147 	int i;
3148 	struct md_rdev *rdev, *freshest, *tmp;
3149 	char b[BDEVNAME_SIZE];
3150 
3151 	freshest = NULL;
3152 	rdev_for_each(rdev, tmp, mddev)
3153 		switch (super_types[mddev->major_version].
3154 			load_super(rdev, freshest, mddev->minor_version)) {
3155 		case 1:
3156 			freshest = rdev;
3157 			break;
3158 		case 0:
3159 			break;
3160 		default:
3161 			printk( KERN_ERR \
3162 				"md: fatal superblock inconsistency in %s"
3163 				" -- removing from array\n",
3164 				bdevname(rdev->bdev,b));
3165 			kick_rdev_from_array(rdev);
3166 		}
3167 
3168 
3169 	super_types[mddev->major_version].
3170 		validate_super(mddev, freshest);
3171 
3172 	i = 0;
3173 	rdev_for_each(rdev, tmp, mddev) {
3174 		if (mddev->max_disks &&
3175 		    (rdev->desc_nr >= mddev->max_disks ||
3176 		     i > mddev->max_disks)) {
3177 			printk(KERN_WARNING
3178 			       "md: %s: %s: only %d devices permitted\n",
3179 			       mdname(mddev), bdevname(rdev->bdev, b),
3180 			       mddev->max_disks);
3181 			kick_rdev_from_array(rdev);
3182 			continue;
3183 		}
3184 		if (rdev != freshest)
3185 			if (super_types[mddev->major_version].
3186 			    validate_super(mddev, rdev)) {
3187 				printk(KERN_WARNING "md: kicking non-fresh %s"
3188 					" from array!\n",
3189 					bdevname(rdev->bdev,b));
3190 				kick_rdev_from_array(rdev);
3191 				continue;
3192 			}
3193 		if (mddev->level == LEVEL_MULTIPATH) {
3194 			rdev->desc_nr = i++;
3195 			rdev->raid_disk = rdev->desc_nr;
3196 			set_bit(In_sync, &rdev->flags);
3197 		} else if (rdev->raid_disk >= (mddev->raid_disks - min(0, mddev->delta_disks))) {
3198 			rdev->raid_disk = -1;
3199 			clear_bit(In_sync, &rdev->flags);
3200 		}
3201 	}
3202 }
3203 
3204 /* Read a fixed-point number.
3205  * Numbers in sysfs attributes should be in "standard" units where
3206  * possible, so time should be in seconds.
3207  * However we internally use a a much smaller unit such as
3208  * milliseconds or jiffies.
3209  * This function takes a decimal number with a possible fractional
3210  * component, and produces an integer which is the result of
3211  * multiplying that number by 10^'scale'.
3212  * all without any floating-point arithmetic.
3213  */
3214 int strict_strtoul_scaled(const char *cp, unsigned long *res, int scale)
3215 {
3216 	unsigned long result = 0;
3217 	long decimals = -1;
3218 	while (isdigit(*cp) || (*cp == '.' && decimals < 0)) {
3219 		if (*cp == '.')
3220 			decimals = 0;
3221 		else if (decimals < scale) {
3222 			unsigned int value;
3223 			value = *cp - '0';
3224 			result = result * 10 + value;
3225 			if (decimals >= 0)
3226 				decimals++;
3227 		}
3228 		cp++;
3229 	}
3230 	if (*cp == '\n')
3231 		cp++;
3232 	if (*cp)
3233 		return -EINVAL;
3234 	if (decimals < 0)
3235 		decimals = 0;
3236 	while (decimals < scale) {
3237 		result *= 10;
3238 		decimals ++;
3239 	}
3240 	*res = result;
3241 	return 0;
3242 }
3243 
3244 
3245 static void md_safemode_timeout(unsigned long data);
3246 
3247 static ssize_t
3248 safe_delay_show(struct mddev *mddev, char *page)
3249 {
3250 	int msec = (mddev->safemode_delay*1000)/HZ;
3251 	return sprintf(page, "%d.%03d\n", msec/1000, msec%1000);
3252 }
3253 static ssize_t
3254 safe_delay_store(struct mddev *mddev, const char *cbuf, size_t len)
3255 {
3256 	unsigned long msec;
3257 
3258 	if (strict_strtoul_scaled(cbuf, &msec, 3) < 0)
3259 		return -EINVAL;
3260 	if (msec == 0)
3261 		mddev->safemode_delay = 0;
3262 	else {
3263 		unsigned long old_delay = mddev->safemode_delay;
3264 		mddev->safemode_delay = (msec*HZ)/1000;
3265 		if (mddev->safemode_delay == 0)
3266 			mddev->safemode_delay = 1;
3267 		if (mddev->safemode_delay < old_delay)
3268 			md_safemode_timeout((unsigned long)mddev);
3269 	}
3270 	return len;
3271 }
3272 static struct md_sysfs_entry md_safe_delay =
3273 __ATTR(safe_mode_delay, S_IRUGO|S_IWUSR,safe_delay_show, safe_delay_store);
3274 
3275 static ssize_t
3276 level_show(struct mddev *mddev, char *page)
3277 {
3278 	struct md_personality *p = mddev->pers;
3279 	if (p)
3280 		return sprintf(page, "%s\n", p->name);
3281 	else if (mddev->clevel[0])
3282 		return sprintf(page, "%s\n", mddev->clevel);
3283 	else if (mddev->level != LEVEL_NONE)
3284 		return sprintf(page, "%d\n", mddev->level);
3285 	else
3286 		return 0;
3287 }
3288 
3289 static ssize_t
3290 level_store(struct mddev *mddev, const char *buf, size_t len)
3291 {
3292 	char clevel[16];
3293 	ssize_t rv = len;
3294 	struct md_personality *pers;
3295 	long level;
3296 	void *priv;
3297 	struct md_rdev *rdev;
3298 
3299 	if (mddev->pers == NULL) {
3300 		if (len == 0)
3301 			return 0;
3302 		if (len >= sizeof(mddev->clevel))
3303 			return -ENOSPC;
3304 		strncpy(mddev->clevel, buf, len);
3305 		if (mddev->clevel[len-1] == '\n')
3306 			len--;
3307 		mddev->clevel[len] = 0;
3308 		mddev->level = LEVEL_NONE;
3309 		return rv;
3310 	}
3311 
3312 	/* request to change the personality.  Need to ensure:
3313 	 *  - array is not engaged in resync/recovery/reshape
3314 	 *  - old personality can be suspended
3315 	 *  - new personality will access other array.
3316 	 */
3317 
3318 	if (mddev->sync_thread ||
3319 	    mddev->reshape_position != MaxSector ||
3320 	    mddev->sysfs_active)
3321 		return -EBUSY;
3322 
3323 	if (!mddev->pers->quiesce) {
3324 		printk(KERN_WARNING "md: %s: %s does not support online personality change\n",
3325 		       mdname(mddev), mddev->pers->name);
3326 		return -EINVAL;
3327 	}
3328 
3329 	/* Now find the new personality */
3330 	if (len == 0 || len >= sizeof(clevel))
3331 		return -EINVAL;
3332 	strncpy(clevel, buf, len);
3333 	if (clevel[len-1] == '\n')
3334 		len--;
3335 	clevel[len] = 0;
3336 	if (strict_strtol(clevel, 10, &level))
3337 		level = LEVEL_NONE;
3338 
3339 	if (request_module("md-%s", clevel) != 0)
3340 		request_module("md-level-%s", clevel);
3341 	spin_lock(&pers_lock);
3342 	pers = find_pers(level, clevel);
3343 	if (!pers || !try_module_get(pers->owner)) {
3344 		spin_unlock(&pers_lock);
3345 		printk(KERN_WARNING "md: personality %s not loaded\n", clevel);
3346 		return -EINVAL;
3347 	}
3348 	spin_unlock(&pers_lock);
3349 
3350 	if (pers == mddev->pers) {
3351 		/* Nothing to do! */
3352 		module_put(pers->owner);
3353 		return rv;
3354 	}
3355 	if (!pers->takeover) {
3356 		module_put(pers->owner);
3357 		printk(KERN_WARNING "md: %s: %s does not support personality takeover\n",
3358 		       mdname(mddev), clevel);
3359 		return -EINVAL;
3360 	}
3361 
3362 	list_for_each_entry(rdev, &mddev->disks, same_set)
3363 		rdev->new_raid_disk = rdev->raid_disk;
3364 
3365 	/* ->takeover must set new_* and/or delta_disks
3366 	 * if it succeeds, and may set them when it fails.
3367 	 */
3368 	priv = pers->takeover(mddev);
3369 	if (IS_ERR(priv)) {
3370 		mddev->new_level = mddev->level;
3371 		mddev->new_layout = mddev->layout;
3372 		mddev->new_chunk_sectors = mddev->chunk_sectors;
3373 		mddev->raid_disks -= mddev->delta_disks;
3374 		mddev->delta_disks = 0;
3375 		module_put(pers->owner);
3376 		printk(KERN_WARNING "md: %s: %s would not accept array\n",
3377 		       mdname(mddev), clevel);
3378 		return PTR_ERR(priv);
3379 	}
3380 
3381 	/* Looks like we have a winner */
3382 	mddev_suspend(mddev);
3383 	mddev->pers->stop(mddev);
3384 
3385 	if (mddev->pers->sync_request == NULL &&
3386 	    pers->sync_request != NULL) {
3387 		/* need to add the md_redundancy_group */
3388 		if (sysfs_create_group(&mddev->kobj, &md_redundancy_group))
3389 			printk(KERN_WARNING
3390 			       "md: cannot register extra attributes for %s\n",
3391 			       mdname(mddev));
3392 		mddev->sysfs_action = sysfs_get_dirent(mddev->kobj.sd, NULL, "sync_action");
3393 	}
3394 	if (mddev->pers->sync_request != NULL &&
3395 	    pers->sync_request == NULL) {
3396 		/* need to remove the md_redundancy_group */
3397 		if (mddev->to_remove == NULL)
3398 			mddev->to_remove = &md_redundancy_group;
3399 	}
3400 
3401 	if (mddev->pers->sync_request == NULL &&
3402 	    mddev->external) {
3403 		/* We are converting from a no-redundancy array
3404 		 * to a redundancy array and metadata is managed
3405 		 * externally so we need to be sure that writes
3406 		 * won't block due to a need to transition
3407 		 *      clean->dirty
3408 		 * until external management is started.
3409 		 */
3410 		mddev->in_sync = 0;
3411 		mddev->safemode_delay = 0;
3412 		mddev->safemode = 0;
3413 	}
3414 
3415 	list_for_each_entry(rdev, &mddev->disks, same_set) {
3416 		if (rdev->raid_disk < 0)
3417 			continue;
3418 		if (rdev->new_raid_disk >= mddev->raid_disks)
3419 			rdev->new_raid_disk = -1;
3420 		if (rdev->new_raid_disk == rdev->raid_disk)
3421 			continue;
3422 		sysfs_unlink_rdev(mddev, rdev);
3423 	}
3424 	list_for_each_entry(rdev, &mddev->disks, same_set) {
3425 		if (rdev->raid_disk < 0)
3426 			continue;
3427 		if (rdev->new_raid_disk == rdev->raid_disk)
3428 			continue;
3429 		rdev->raid_disk = rdev->new_raid_disk;
3430 		if (rdev->raid_disk < 0)
3431 			clear_bit(In_sync, &rdev->flags);
3432 		else {
3433 			if (sysfs_link_rdev(mddev, rdev))
3434 				printk(KERN_WARNING "md: cannot register rd%d"
3435 				       " for %s after level change\n",
3436 				       rdev->raid_disk, mdname(mddev));
3437 		}
3438 	}
3439 
3440 	module_put(mddev->pers->owner);
3441 	mddev->pers = pers;
3442 	mddev->private = priv;
3443 	strlcpy(mddev->clevel, pers->name, sizeof(mddev->clevel));
3444 	mddev->level = mddev->new_level;
3445 	mddev->layout = mddev->new_layout;
3446 	mddev->chunk_sectors = mddev->new_chunk_sectors;
3447 	mddev->delta_disks = 0;
3448 	mddev->degraded = 0;
3449 	if (mddev->pers->sync_request == NULL) {
3450 		/* this is now an array without redundancy, so
3451 		 * it must always be in_sync
3452 		 */
3453 		mddev->in_sync = 1;
3454 		del_timer_sync(&mddev->safemode_timer);
3455 	}
3456 	pers->run(mddev);
3457 	mddev_resume(mddev);
3458 	set_bit(MD_CHANGE_DEVS, &mddev->flags);
3459 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
3460 	md_wakeup_thread(mddev->thread);
3461 	sysfs_notify(&mddev->kobj, NULL, "level");
3462 	md_new_event(mddev);
3463 	return rv;
3464 }
3465 
3466 static struct md_sysfs_entry md_level =
3467 __ATTR(level, S_IRUGO|S_IWUSR, level_show, level_store);
3468 
3469 
3470 static ssize_t
3471 layout_show(struct mddev *mddev, char *page)
3472 {
3473 	/* just a number, not meaningful for all levels */
3474 	if (mddev->reshape_position != MaxSector &&
3475 	    mddev->layout != mddev->new_layout)
3476 		return sprintf(page, "%d (%d)\n",
3477 			       mddev->new_layout, mddev->layout);
3478 	return sprintf(page, "%d\n", mddev->layout);
3479 }
3480 
3481 static ssize_t
3482 layout_store(struct mddev *mddev, const char *buf, size_t len)
3483 {
3484 	char *e;
3485 	unsigned long n = simple_strtoul(buf, &e, 10);
3486 
3487 	if (!*buf || (*e && *e != '\n'))
3488 		return -EINVAL;
3489 
3490 	if (mddev->pers) {
3491 		int err;
3492 		if (mddev->pers->check_reshape == NULL)
3493 			return -EBUSY;
3494 		mddev->new_layout = n;
3495 		err = mddev->pers->check_reshape(mddev);
3496 		if (err) {
3497 			mddev->new_layout = mddev->layout;
3498 			return err;
3499 		}
3500 	} else {
3501 		mddev->new_layout = n;
3502 		if (mddev->reshape_position == MaxSector)
3503 			mddev->layout = n;
3504 	}
3505 	return len;
3506 }
3507 static struct md_sysfs_entry md_layout =
3508 __ATTR(layout, S_IRUGO|S_IWUSR, layout_show, layout_store);
3509 
3510 
3511 static ssize_t
3512 raid_disks_show(struct mddev *mddev, char *page)
3513 {
3514 	if (mddev->raid_disks == 0)
3515 		return 0;
3516 	if (mddev->reshape_position != MaxSector &&
3517 	    mddev->delta_disks != 0)
3518 		return sprintf(page, "%d (%d)\n", mddev->raid_disks,
3519 			       mddev->raid_disks - mddev->delta_disks);
3520 	return sprintf(page, "%d\n", mddev->raid_disks);
3521 }
3522 
3523 static int update_raid_disks(struct mddev *mddev, int raid_disks);
3524 
3525 static ssize_t
3526 raid_disks_store(struct mddev *mddev, const char *buf, size_t len)
3527 {
3528 	char *e;
3529 	int rv = 0;
3530 	unsigned long n = simple_strtoul(buf, &e, 10);
3531 
3532 	if (!*buf || (*e && *e != '\n'))
3533 		return -EINVAL;
3534 
3535 	if (mddev->pers)
3536 		rv = update_raid_disks(mddev, n);
3537 	else if (mddev->reshape_position != MaxSector) {
3538 		int olddisks = mddev->raid_disks - mddev->delta_disks;
3539 		mddev->delta_disks = n - olddisks;
3540 		mddev->raid_disks = n;
3541 	} else
3542 		mddev->raid_disks = n;
3543 	return rv ? rv : len;
3544 }
3545 static struct md_sysfs_entry md_raid_disks =
3546 __ATTR(raid_disks, S_IRUGO|S_IWUSR, raid_disks_show, raid_disks_store);
3547 
3548 static ssize_t
3549 chunk_size_show(struct mddev *mddev, char *page)
3550 {
3551 	if (mddev->reshape_position != MaxSector &&
3552 	    mddev->chunk_sectors != mddev->new_chunk_sectors)
3553 		return sprintf(page, "%d (%d)\n",
3554 			       mddev->new_chunk_sectors << 9,
3555 			       mddev->chunk_sectors << 9);
3556 	return sprintf(page, "%d\n", mddev->chunk_sectors << 9);
3557 }
3558 
3559 static ssize_t
3560 chunk_size_store(struct mddev *mddev, const char *buf, size_t len)
3561 {
3562 	char *e;
3563 	unsigned long n = simple_strtoul(buf, &e, 10);
3564 
3565 	if (!*buf || (*e && *e != '\n'))
3566 		return -EINVAL;
3567 
3568 	if (mddev->pers) {
3569 		int err;
3570 		if (mddev->pers->check_reshape == NULL)
3571 			return -EBUSY;
3572 		mddev->new_chunk_sectors = n >> 9;
3573 		err = mddev->pers->check_reshape(mddev);
3574 		if (err) {
3575 			mddev->new_chunk_sectors = mddev->chunk_sectors;
3576 			return err;
3577 		}
3578 	} else {
3579 		mddev->new_chunk_sectors = n >> 9;
3580 		if (mddev->reshape_position == MaxSector)
3581 			mddev->chunk_sectors = n >> 9;
3582 	}
3583 	return len;
3584 }
3585 static struct md_sysfs_entry md_chunk_size =
3586 __ATTR(chunk_size, S_IRUGO|S_IWUSR, chunk_size_show, chunk_size_store);
3587 
3588 static ssize_t
3589 resync_start_show(struct mddev *mddev, char *page)
3590 {
3591 	if (mddev->recovery_cp == MaxSector)
3592 		return sprintf(page, "none\n");
3593 	return sprintf(page, "%llu\n", (unsigned long long)mddev->recovery_cp);
3594 }
3595 
3596 static ssize_t
3597 resync_start_store(struct mddev *mddev, const char *buf, size_t len)
3598 {
3599 	char *e;
3600 	unsigned long long n = simple_strtoull(buf, &e, 10);
3601 
3602 	if (mddev->pers && !test_bit(MD_RECOVERY_FROZEN, &mddev->recovery))
3603 		return -EBUSY;
3604 	if (cmd_match(buf, "none"))
3605 		n = MaxSector;
3606 	else if (!*buf || (*e && *e != '\n'))
3607 		return -EINVAL;
3608 
3609 	mddev->recovery_cp = n;
3610 	return len;
3611 }
3612 static struct md_sysfs_entry md_resync_start =
3613 __ATTR(resync_start, S_IRUGO|S_IWUSR, resync_start_show, resync_start_store);
3614 
3615 /*
3616  * The array state can be:
3617  *
3618  * clear
3619  *     No devices, no size, no level
3620  *     Equivalent to STOP_ARRAY ioctl
3621  * inactive
3622  *     May have some settings, but array is not active
3623  *        all IO results in error
3624  *     When written, doesn't tear down array, but just stops it
3625  * suspended (not supported yet)
3626  *     All IO requests will block. The array can be reconfigured.
3627  *     Writing this, if accepted, will block until array is quiescent
3628  * readonly
3629  *     no resync can happen.  no superblocks get written.
3630  *     write requests fail
3631  * read-auto
3632  *     like readonly, but behaves like 'clean' on a write request.
3633  *
3634  * clean - no pending writes, but otherwise active.
3635  *     When written to inactive array, starts without resync
3636  *     If a write request arrives then
3637  *       if metadata is known, mark 'dirty' and switch to 'active'.
3638  *       if not known, block and switch to write-pending
3639  *     If written to an active array that has pending writes, then fails.
3640  * active
3641  *     fully active: IO and resync can be happening.
3642  *     When written to inactive array, starts with resync
3643  *
3644  * write-pending
3645  *     clean, but writes are blocked waiting for 'active' to be written.
3646  *
3647  * active-idle
3648  *     like active, but no writes have been seen for a while (100msec).
3649  *
3650  */
3651 enum array_state { clear, inactive, suspended, readonly, read_auto, clean, active,
3652 		   write_pending, active_idle, bad_word};
3653 static char *array_states[] = {
3654 	"clear", "inactive", "suspended", "readonly", "read-auto", "clean", "active",
3655 	"write-pending", "active-idle", NULL };
3656 
3657 static int match_word(const char *word, char **list)
3658 {
3659 	int n;
3660 	for (n=0; list[n]; n++)
3661 		if (cmd_match(word, list[n]))
3662 			break;
3663 	return n;
3664 }
3665 
3666 static ssize_t
3667 array_state_show(struct mddev *mddev, char *page)
3668 {
3669 	enum array_state st = inactive;
3670 
3671 	if (mddev->pers)
3672 		switch(mddev->ro) {
3673 		case 1:
3674 			st = readonly;
3675 			break;
3676 		case 2:
3677 			st = read_auto;
3678 			break;
3679 		case 0:
3680 			if (mddev->in_sync)
3681 				st = clean;
3682 			else if (test_bit(MD_CHANGE_PENDING, &mddev->flags))
3683 				st = write_pending;
3684 			else if (mddev->safemode)
3685 				st = active_idle;
3686 			else
3687 				st = active;
3688 		}
3689 	else {
3690 		if (list_empty(&mddev->disks) &&
3691 		    mddev->raid_disks == 0 &&
3692 		    mddev->dev_sectors == 0)
3693 			st = clear;
3694 		else
3695 			st = inactive;
3696 	}
3697 	return sprintf(page, "%s\n", array_states[st]);
3698 }
3699 
3700 static int do_md_stop(struct mddev * mddev, int ro, int is_open);
3701 static int md_set_readonly(struct mddev * mddev, int is_open);
3702 static int do_md_run(struct mddev * mddev);
3703 static int restart_array(struct mddev *mddev);
3704 
3705 static ssize_t
3706 array_state_store(struct mddev *mddev, const char *buf, size_t len)
3707 {
3708 	int err = -EINVAL;
3709 	enum array_state st = match_word(buf, array_states);
3710 	switch(st) {
3711 	case bad_word:
3712 		break;
3713 	case clear:
3714 		/* stopping an active array */
3715 		if (atomic_read(&mddev->openers) > 0)
3716 			return -EBUSY;
3717 		err = do_md_stop(mddev, 0, 0);
3718 		break;
3719 	case inactive:
3720 		/* stopping an active array */
3721 		if (mddev->pers) {
3722 			if (atomic_read(&mddev->openers) > 0)
3723 				return -EBUSY;
3724 			err = do_md_stop(mddev, 2, 0);
3725 		} else
3726 			err = 0; /* already inactive */
3727 		break;
3728 	case suspended:
3729 		break; /* not supported yet */
3730 	case readonly:
3731 		if (mddev->pers)
3732 			err = md_set_readonly(mddev, 0);
3733 		else {
3734 			mddev->ro = 1;
3735 			set_disk_ro(mddev->gendisk, 1);
3736 			err = do_md_run(mddev);
3737 		}
3738 		break;
3739 	case read_auto:
3740 		if (mddev->pers) {
3741 			if (mddev->ro == 0)
3742 				err = md_set_readonly(mddev, 0);
3743 			else if (mddev->ro == 1)
3744 				err = restart_array(mddev);
3745 			if (err == 0) {
3746 				mddev->ro = 2;
3747 				set_disk_ro(mddev->gendisk, 0);
3748 			}
3749 		} else {
3750 			mddev->ro = 2;
3751 			err = do_md_run(mddev);
3752 		}
3753 		break;
3754 	case clean:
3755 		if (mddev->pers) {
3756 			restart_array(mddev);
3757 			spin_lock_irq(&mddev->write_lock);
3758 			if (atomic_read(&mddev->writes_pending) == 0) {
3759 				if (mddev->in_sync == 0) {
3760 					mddev->in_sync = 1;
3761 					if (mddev->safemode == 1)
3762 						mddev->safemode = 0;
3763 					set_bit(MD_CHANGE_CLEAN, &mddev->flags);
3764 				}
3765 				err = 0;
3766 			} else
3767 				err = -EBUSY;
3768 			spin_unlock_irq(&mddev->write_lock);
3769 		} else
3770 			err = -EINVAL;
3771 		break;
3772 	case active:
3773 		if (mddev->pers) {
3774 			restart_array(mddev);
3775 			clear_bit(MD_CHANGE_PENDING, &mddev->flags);
3776 			wake_up(&mddev->sb_wait);
3777 			err = 0;
3778 		} else {
3779 			mddev->ro = 0;
3780 			set_disk_ro(mddev->gendisk, 0);
3781 			err = do_md_run(mddev);
3782 		}
3783 		break;
3784 	case write_pending:
3785 	case active_idle:
3786 		/* these cannot be set */
3787 		break;
3788 	}
3789 	if (err)
3790 		return err;
3791 	else {
3792 		if (mddev->hold_active == UNTIL_IOCTL)
3793 			mddev->hold_active = 0;
3794 		sysfs_notify_dirent_safe(mddev->sysfs_state);
3795 		return len;
3796 	}
3797 }
3798 static struct md_sysfs_entry md_array_state =
3799 __ATTR(array_state, S_IRUGO|S_IWUSR, array_state_show, array_state_store);
3800 
3801 static ssize_t
3802 max_corrected_read_errors_show(struct mddev *mddev, char *page) {
3803 	return sprintf(page, "%d\n",
3804 		       atomic_read(&mddev->max_corr_read_errors));
3805 }
3806 
3807 static ssize_t
3808 max_corrected_read_errors_store(struct mddev *mddev, const char *buf, size_t len)
3809 {
3810 	char *e;
3811 	unsigned long n = simple_strtoul(buf, &e, 10);
3812 
3813 	if (*buf && (*e == 0 || *e == '\n')) {
3814 		atomic_set(&mddev->max_corr_read_errors, n);
3815 		return len;
3816 	}
3817 	return -EINVAL;
3818 }
3819 
3820 static struct md_sysfs_entry max_corr_read_errors =
3821 __ATTR(max_read_errors, S_IRUGO|S_IWUSR, max_corrected_read_errors_show,
3822 	max_corrected_read_errors_store);
3823 
3824 static ssize_t
3825 null_show(struct mddev *mddev, char *page)
3826 {
3827 	return -EINVAL;
3828 }
3829 
3830 static ssize_t
3831 new_dev_store(struct mddev *mddev, const char *buf, size_t len)
3832 {
3833 	/* buf must be %d:%d\n? giving major and minor numbers */
3834 	/* The new device is added to the array.
3835 	 * If the array has a persistent superblock, we read the
3836 	 * superblock to initialise info and check validity.
3837 	 * Otherwise, only checking done is that in bind_rdev_to_array,
3838 	 * which mainly checks size.
3839 	 */
3840 	char *e;
3841 	int major = simple_strtoul(buf, &e, 10);
3842 	int minor;
3843 	dev_t dev;
3844 	struct md_rdev *rdev;
3845 	int err;
3846 
3847 	if (!*buf || *e != ':' || !e[1] || e[1] == '\n')
3848 		return -EINVAL;
3849 	minor = simple_strtoul(e+1, &e, 10);
3850 	if (*e && *e != '\n')
3851 		return -EINVAL;
3852 	dev = MKDEV(major, minor);
3853 	if (major != MAJOR(dev) ||
3854 	    minor != MINOR(dev))
3855 		return -EOVERFLOW;
3856 
3857 
3858 	if (mddev->persistent) {
3859 		rdev = md_import_device(dev, mddev->major_version,
3860 					mddev->minor_version);
3861 		if (!IS_ERR(rdev) && !list_empty(&mddev->disks)) {
3862 			struct md_rdev *rdev0
3863 				= list_entry(mddev->disks.next,
3864 					     struct md_rdev, same_set);
3865 			err = super_types[mddev->major_version]
3866 				.load_super(rdev, rdev0, mddev->minor_version);
3867 			if (err < 0)
3868 				goto out;
3869 		}
3870 	} else if (mddev->external)
3871 		rdev = md_import_device(dev, -2, -1);
3872 	else
3873 		rdev = md_import_device(dev, -1, -1);
3874 
3875 	if (IS_ERR(rdev))
3876 		return PTR_ERR(rdev);
3877 	err = bind_rdev_to_array(rdev, mddev);
3878  out:
3879 	if (err)
3880 		export_rdev(rdev);
3881 	return err ? err : len;
3882 }
3883 
3884 static struct md_sysfs_entry md_new_device =
3885 __ATTR(new_dev, S_IWUSR, null_show, new_dev_store);
3886 
3887 static ssize_t
3888 bitmap_store(struct mddev *mddev, const char *buf, size_t len)
3889 {
3890 	char *end;
3891 	unsigned long chunk, end_chunk;
3892 
3893 	if (!mddev->bitmap)
3894 		goto out;
3895 	/* buf should be <chunk> <chunk> ... or <chunk>-<chunk> ... (range) */
3896 	while (*buf) {
3897 		chunk = end_chunk = simple_strtoul(buf, &end, 0);
3898 		if (buf == end) break;
3899 		if (*end == '-') { /* range */
3900 			buf = end + 1;
3901 			end_chunk = simple_strtoul(buf, &end, 0);
3902 			if (buf == end) break;
3903 		}
3904 		if (*end && !isspace(*end)) break;
3905 		bitmap_dirty_bits(mddev->bitmap, chunk, end_chunk);
3906 		buf = skip_spaces(end);
3907 	}
3908 	bitmap_unplug(mddev->bitmap); /* flush the bits to disk */
3909 out:
3910 	return len;
3911 }
3912 
3913 static struct md_sysfs_entry md_bitmap =
3914 __ATTR(bitmap_set_bits, S_IWUSR, null_show, bitmap_store);
3915 
3916 static ssize_t
3917 size_show(struct mddev *mddev, char *page)
3918 {
3919 	return sprintf(page, "%llu\n",
3920 		(unsigned long long)mddev->dev_sectors / 2);
3921 }
3922 
3923 static int update_size(struct mddev *mddev, sector_t num_sectors);
3924 
3925 static ssize_t
3926 size_store(struct mddev *mddev, const char *buf, size_t len)
3927 {
3928 	/* If array is inactive, we can reduce the component size, but
3929 	 * not increase it (except from 0).
3930 	 * If array is active, we can try an on-line resize
3931 	 */
3932 	sector_t sectors;
3933 	int err = strict_blocks_to_sectors(buf, &sectors);
3934 
3935 	if (err < 0)
3936 		return err;
3937 	if (mddev->pers) {
3938 		err = update_size(mddev, sectors);
3939 		md_update_sb(mddev, 1);
3940 	} else {
3941 		if (mddev->dev_sectors == 0 ||
3942 		    mddev->dev_sectors > sectors)
3943 			mddev->dev_sectors = sectors;
3944 		else
3945 			err = -ENOSPC;
3946 	}
3947 	return err ? err : len;
3948 }
3949 
3950 static struct md_sysfs_entry md_size =
3951 __ATTR(component_size, S_IRUGO|S_IWUSR, size_show, size_store);
3952 
3953 
3954 /* Metdata version.
3955  * This is one of
3956  *   'none' for arrays with no metadata (good luck...)
3957  *   'external' for arrays with externally managed metadata,
3958  * or N.M for internally known formats
3959  */
3960 static ssize_t
3961 metadata_show(struct mddev *mddev, char *page)
3962 {
3963 	if (mddev->persistent)
3964 		return sprintf(page, "%d.%d\n",
3965 			       mddev->major_version, mddev->minor_version);
3966 	else if (mddev->external)
3967 		return sprintf(page, "external:%s\n", mddev->metadata_type);
3968 	else
3969 		return sprintf(page, "none\n");
3970 }
3971 
3972 static ssize_t
3973 metadata_store(struct mddev *mddev, const char *buf, size_t len)
3974 {
3975 	int major, minor;
3976 	char *e;
3977 	/* Changing the details of 'external' metadata is
3978 	 * always permitted.  Otherwise there must be
3979 	 * no devices attached to the array.
3980 	 */
3981 	if (mddev->external && strncmp(buf, "external:", 9) == 0)
3982 		;
3983 	else if (!list_empty(&mddev->disks))
3984 		return -EBUSY;
3985 
3986 	if (cmd_match(buf, "none")) {
3987 		mddev->persistent = 0;
3988 		mddev->external = 0;
3989 		mddev->major_version = 0;
3990 		mddev->minor_version = 90;
3991 		return len;
3992 	}
3993 	if (strncmp(buf, "external:", 9) == 0) {
3994 		size_t namelen = len-9;
3995 		if (namelen >= sizeof(mddev->metadata_type))
3996 			namelen = sizeof(mddev->metadata_type)-1;
3997 		strncpy(mddev->metadata_type, buf+9, namelen);
3998 		mddev->metadata_type[namelen] = 0;
3999 		if (namelen && mddev->metadata_type[namelen-1] == '\n')
4000 			mddev->metadata_type[--namelen] = 0;
4001 		mddev->persistent = 0;
4002 		mddev->external = 1;
4003 		mddev->major_version = 0;
4004 		mddev->minor_version = 90;
4005 		return len;
4006 	}
4007 	major = simple_strtoul(buf, &e, 10);
4008 	if (e==buf || *e != '.')
4009 		return -EINVAL;
4010 	buf = e+1;
4011 	minor = simple_strtoul(buf, &e, 10);
4012 	if (e==buf || (*e && *e != '\n') )
4013 		return -EINVAL;
4014 	if (major >= ARRAY_SIZE(super_types) || super_types[major].name == NULL)
4015 		return -ENOENT;
4016 	mddev->major_version = major;
4017 	mddev->minor_version = minor;
4018 	mddev->persistent = 1;
4019 	mddev->external = 0;
4020 	return len;
4021 }
4022 
4023 static struct md_sysfs_entry md_metadata =
4024 __ATTR(metadata_version, S_IRUGO|S_IWUSR, metadata_show, metadata_store);
4025 
4026 static ssize_t
4027 action_show(struct mddev *mddev, char *page)
4028 {
4029 	char *type = "idle";
4030 	if (test_bit(MD_RECOVERY_FROZEN, &mddev->recovery))
4031 		type = "frozen";
4032 	else if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
4033 	    (!mddev->ro && test_bit(MD_RECOVERY_NEEDED, &mddev->recovery))) {
4034 		if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
4035 			type = "reshape";
4036 		else if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
4037 			if (!test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
4038 				type = "resync";
4039 			else if (test_bit(MD_RECOVERY_CHECK, &mddev->recovery))
4040 				type = "check";
4041 			else
4042 				type = "repair";
4043 		} else if (test_bit(MD_RECOVERY_RECOVER, &mddev->recovery))
4044 			type = "recover";
4045 	}
4046 	return sprintf(page, "%s\n", type);
4047 }
4048 
4049 static void reap_sync_thread(struct mddev *mddev);
4050 
4051 static ssize_t
4052 action_store(struct mddev *mddev, const char *page, size_t len)
4053 {
4054 	if (!mddev->pers || !mddev->pers->sync_request)
4055 		return -EINVAL;
4056 
4057 	if (cmd_match(page, "frozen"))
4058 		set_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
4059 	else
4060 		clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
4061 
4062 	if (cmd_match(page, "idle") || cmd_match(page, "frozen")) {
4063 		if (mddev->sync_thread) {
4064 			set_bit(MD_RECOVERY_INTR, &mddev->recovery);
4065 			reap_sync_thread(mddev);
4066 		}
4067 	} else if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
4068 		   test_bit(MD_RECOVERY_NEEDED, &mddev->recovery))
4069 		return -EBUSY;
4070 	else if (cmd_match(page, "resync"))
4071 		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
4072 	else if (cmd_match(page, "recover")) {
4073 		set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
4074 		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
4075 	} else if (cmd_match(page, "reshape")) {
4076 		int err;
4077 		if (mddev->pers->start_reshape == NULL)
4078 			return -EINVAL;
4079 		err = mddev->pers->start_reshape(mddev);
4080 		if (err)
4081 			return err;
4082 		sysfs_notify(&mddev->kobj, NULL, "degraded");
4083 	} else {
4084 		if (cmd_match(page, "check"))
4085 			set_bit(MD_RECOVERY_CHECK, &mddev->recovery);
4086 		else if (!cmd_match(page, "repair"))
4087 			return -EINVAL;
4088 		set_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
4089 		set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
4090 	}
4091 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
4092 	md_wakeup_thread(mddev->thread);
4093 	sysfs_notify_dirent_safe(mddev->sysfs_action);
4094 	return len;
4095 }
4096 
4097 static ssize_t
4098 mismatch_cnt_show(struct mddev *mddev, char *page)
4099 {
4100 	return sprintf(page, "%llu\n",
4101 		       (unsigned long long) mddev->resync_mismatches);
4102 }
4103 
4104 static struct md_sysfs_entry md_scan_mode =
4105 __ATTR(sync_action, S_IRUGO|S_IWUSR, action_show, action_store);
4106 
4107 
4108 static struct md_sysfs_entry md_mismatches = __ATTR_RO(mismatch_cnt);
4109 
4110 static ssize_t
4111 sync_min_show(struct mddev *mddev, char *page)
4112 {
4113 	return sprintf(page, "%d (%s)\n", speed_min(mddev),
4114 		       mddev->sync_speed_min ? "local": "system");
4115 }
4116 
4117 static ssize_t
4118 sync_min_store(struct mddev *mddev, const char *buf, size_t len)
4119 {
4120 	int min;
4121 	char *e;
4122 	if (strncmp(buf, "system", 6)==0) {
4123 		mddev->sync_speed_min = 0;
4124 		return len;
4125 	}
4126 	min = simple_strtoul(buf, &e, 10);
4127 	if (buf == e || (*e && *e != '\n') || min <= 0)
4128 		return -EINVAL;
4129 	mddev->sync_speed_min = min;
4130 	return len;
4131 }
4132 
4133 static struct md_sysfs_entry md_sync_min =
4134 __ATTR(sync_speed_min, S_IRUGO|S_IWUSR, sync_min_show, sync_min_store);
4135 
4136 static ssize_t
4137 sync_max_show(struct mddev *mddev, char *page)
4138 {
4139 	return sprintf(page, "%d (%s)\n", speed_max(mddev),
4140 		       mddev->sync_speed_max ? "local": "system");
4141 }
4142 
4143 static ssize_t
4144 sync_max_store(struct mddev *mddev, const char *buf, size_t len)
4145 {
4146 	int max;
4147 	char *e;
4148 	if (strncmp(buf, "system", 6)==0) {
4149 		mddev->sync_speed_max = 0;
4150 		return len;
4151 	}
4152 	max = simple_strtoul(buf, &e, 10);
4153 	if (buf == e || (*e && *e != '\n') || max <= 0)
4154 		return -EINVAL;
4155 	mddev->sync_speed_max = max;
4156 	return len;
4157 }
4158 
4159 static struct md_sysfs_entry md_sync_max =
4160 __ATTR(sync_speed_max, S_IRUGO|S_IWUSR, sync_max_show, sync_max_store);
4161 
4162 static ssize_t
4163 degraded_show(struct mddev *mddev, char *page)
4164 {
4165 	return sprintf(page, "%d\n", mddev->degraded);
4166 }
4167 static struct md_sysfs_entry md_degraded = __ATTR_RO(degraded);
4168 
4169 static ssize_t
4170 sync_force_parallel_show(struct mddev *mddev, char *page)
4171 {
4172 	return sprintf(page, "%d\n", mddev->parallel_resync);
4173 }
4174 
4175 static ssize_t
4176 sync_force_parallel_store(struct mddev *mddev, const char *buf, size_t len)
4177 {
4178 	long n;
4179 
4180 	if (strict_strtol(buf, 10, &n))
4181 		return -EINVAL;
4182 
4183 	if (n != 0 && n != 1)
4184 		return -EINVAL;
4185 
4186 	mddev->parallel_resync = n;
4187 
4188 	if (mddev->sync_thread)
4189 		wake_up(&resync_wait);
4190 
4191 	return len;
4192 }
4193 
4194 /* force parallel resync, even with shared block devices */
4195 static struct md_sysfs_entry md_sync_force_parallel =
4196 __ATTR(sync_force_parallel, S_IRUGO|S_IWUSR,
4197        sync_force_parallel_show, sync_force_parallel_store);
4198 
4199 static ssize_t
4200 sync_speed_show(struct mddev *mddev, char *page)
4201 {
4202 	unsigned long resync, dt, db;
4203 	if (mddev->curr_resync == 0)
4204 		return sprintf(page, "none\n");
4205 	resync = mddev->curr_mark_cnt - atomic_read(&mddev->recovery_active);
4206 	dt = (jiffies - mddev->resync_mark) / HZ;
4207 	if (!dt) dt++;
4208 	db = resync - mddev->resync_mark_cnt;
4209 	return sprintf(page, "%lu\n", db/dt/2); /* K/sec */
4210 }
4211 
4212 static struct md_sysfs_entry md_sync_speed = __ATTR_RO(sync_speed);
4213 
4214 static ssize_t
4215 sync_completed_show(struct mddev *mddev, char *page)
4216 {
4217 	unsigned long long max_sectors, resync;
4218 
4219 	if (!test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
4220 		return sprintf(page, "none\n");
4221 
4222 	if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery))
4223 		max_sectors = mddev->resync_max_sectors;
4224 	else
4225 		max_sectors = mddev->dev_sectors;
4226 
4227 	resync = mddev->curr_resync_completed;
4228 	return sprintf(page, "%llu / %llu\n", resync, max_sectors);
4229 }
4230 
4231 static struct md_sysfs_entry md_sync_completed = __ATTR_RO(sync_completed);
4232 
4233 static ssize_t
4234 min_sync_show(struct mddev *mddev, char *page)
4235 {
4236 	return sprintf(page, "%llu\n",
4237 		       (unsigned long long)mddev->resync_min);
4238 }
4239 static ssize_t
4240 min_sync_store(struct mddev *mddev, const char *buf, size_t len)
4241 {
4242 	unsigned long long min;
4243 	if (strict_strtoull(buf, 10, &min))
4244 		return -EINVAL;
4245 	if (min > mddev->resync_max)
4246 		return -EINVAL;
4247 	if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
4248 		return -EBUSY;
4249 
4250 	/* Must be a multiple of chunk_size */
4251 	if (mddev->chunk_sectors) {
4252 		sector_t temp = min;
4253 		if (sector_div(temp, mddev->chunk_sectors))
4254 			return -EINVAL;
4255 	}
4256 	mddev->resync_min = min;
4257 
4258 	return len;
4259 }
4260 
4261 static struct md_sysfs_entry md_min_sync =
4262 __ATTR(sync_min, S_IRUGO|S_IWUSR, min_sync_show, min_sync_store);
4263 
4264 static ssize_t
4265 max_sync_show(struct mddev *mddev, char *page)
4266 {
4267 	if (mddev->resync_max == MaxSector)
4268 		return sprintf(page, "max\n");
4269 	else
4270 		return sprintf(page, "%llu\n",
4271 			       (unsigned long long)mddev->resync_max);
4272 }
4273 static ssize_t
4274 max_sync_store(struct mddev *mddev, const char *buf, size_t len)
4275 {
4276 	if (strncmp(buf, "max", 3) == 0)
4277 		mddev->resync_max = MaxSector;
4278 	else {
4279 		unsigned long long max;
4280 		if (strict_strtoull(buf, 10, &max))
4281 			return -EINVAL;
4282 		if (max < mddev->resync_min)
4283 			return -EINVAL;
4284 		if (max < mddev->resync_max &&
4285 		    mddev->ro == 0 &&
4286 		    test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
4287 			return -EBUSY;
4288 
4289 		/* Must be a multiple of chunk_size */
4290 		if (mddev->chunk_sectors) {
4291 			sector_t temp = max;
4292 			if (sector_div(temp, mddev->chunk_sectors))
4293 				return -EINVAL;
4294 		}
4295 		mddev->resync_max = max;
4296 	}
4297 	wake_up(&mddev->recovery_wait);
4298 	return len;
4299 }
4300 
4301 static struct md_sysfs_entry md_max_sync =
4302 __ATTR(sync_max, S_IRUGO|S_IWUSR, max_sync_show, max_sync_store);
4303 
4304 static ssize_t
4305 suspend_lo_show(struct mddev *mddev, char *page)
4306 {
4307 	return sprintf(page, "%llu\n", (unsigned long long)mddev->suspend_lo);
4308 }
4309 
4310 static ssize_t
4311 suspend_lo_store(struct mddev *mddev, const char *buf, size_t len)
4312 {
4313 	char *e;
4314 	unsigned long long new = simple_strtoull(buf, &e, 10);
4315 	unsigned long long old = mddev->suspend_lo;
4316 
4317 	if (mddev->pers == NULL ||
4318 	    mddev->pers->quiesce == NULL)
4319 		return -EINVAL;
4320 	if (buf == e || (*e && *e != '\n'))
4321 		return -EINVAL;
4322 
4323 	mddev->suspend_lo = new;
4324 	if (new >= old)
4325 		/* Shrinking suspended region */
4326 		mddev->pers->quiesce(mddev, 2);
4327 	else {
4328 		/* Expanding suspended region - need to wait */
4329 		mddev->pers->quiesce(mddev, 1);
4330 		mddev->pers->quiesce(mddev, 0);
4331 	}
4332 	return len;
4333 }
4334 static struct md_sysfs_entry md_suspend_lo =
4335 __ATTR(suspend_lo, S_IRUGO|S_IWUSR, suspend_lo_show, suspend_lo_store);
4336 
4337 
4338 static ssize_t
4339 suspend_hi_show(struct mddev *mddev, char *page)
4340 {
4341 	return sprintf(page, "%llu\n", (unsigned long long)mddev->suspend_hi);
4342 }
4343 
4344 static ssize_t
4345 suspend_hi_store(struct mddev *mddev, const char *buf, size_t len)
4346 {
4347 	char *e;
4348 	unsigned long long new = simple_strtoull(buf, &e, 10);
4349 	unsigned long long old = mddev->suspend_hi;
4350 
4351 	if (mddev->pers == NULL ||
4352 	    mddev->pers->quiesce == NULL)
4353 		return -EINVAL;
4354 	if (buf == e || (*e && *e != '\n'))
4355 		return -EINVAL;
4356 
4357 	mddev->suspend_hi = new;
4358 	if (new <= old)
4359 		/* Shrinking suspended region */
4360 		mddev->pers->quiesce(mddev, 2);
4361 	else {
4362 		/* Expanding suspended region - need to wait */
4363 		mddev->pers->quiesce(mddev, 1);
4364 		mddev->pers->quiesce(mddev, 0);
4365 	}
4366 	return len;
4367 }
4368 static struct md_sysfs_entry md_suspend_hi =
4369 __ATTR(suspend_hi, S_IRUGO|S_IWUSR, suspend_hi_show, suspend_hi_store);
4370 
4371 static ssize_t
4372 reshape_position_show(struct mddev *mddev, char *page)
4373 {
4374 	if (mddev->reshape_position != MaxSector)
4375 		return sprintf(page, "%llu\n",
4376 			       (unsigned long long)mddev->reshape_position);
4377 	strcpy(page, "none\n");
4378 	return 5;
4379 }
4380 
4381 static ssize_t
4382 reshape_position_store(struct mddev *mddev, const char *buf, size_t len)
4383 {
4384 	char *e;
4385 	unsigned long long new = simple_strtoull(buf, &e, 10);
4386 	if (mddev->pers)
4387 		return -EBUSY;
4388 	if (buf == e || (*e && *e != '\n'))
4389 		return -EINVAL;
4390 	mddev->reshape_position = new;
4391 	mddev->delta_disks = 0;
4392 	mddev->new_level = mddev->level;
4393 	mddev->new_layout = mddev->layout;
4394 	mddev->new_chunk_sectors = mddev->chunk_sectors;
4395 	return len;
4396 }
4397 
4398 static struct md_sysfs_entry md_reshape_position =
4399 __ATTR(reshape_position, S_IRUGO|S_IWUSR, reshape_position_show,
4400        reshape_position_store);
4401 
4402 static ssize_t
4403 array_size_show(struct mddev *mddev, char *page)
4404 {
4405 	if (mddev->external_size)
4406 		return sprintf(page, "%llu\n",
4407 			       (unsigned long long)mddev->array_sectors/2);
4408 	else
4409 		return sprintf(page, "default\n");
4410 }
4411 
4412 static ssize_t
4413 array_size_store(struct mddev *mddev, const char *buf, size_t len)
4414 {
4415 	sector_t sectors;
4416 
4417 	if (strncmp(buf, "default", 7) == 0) {
4418 		if (mddev->pers)
4419 			sectors = mddev->pers->size(mddev, 0, 0);
4420 		else
4421 			sectors = mddev->array_sectors;
4422 
4423 		mddev->external_size = 0;
4424 	} else {
4425 		if (strict_blocks_to_sectors(buf, &sectors) < 0)
4426 			return -EINVAL;
4427 		if (mddev->pers && mddev->pers->size(mddev, 0, 0) < sectors)
4428 			return -E2BIG;
4429 
4430 		mddev->external_size = 1;
4431 	}
4432 
4433 	mddev->array_sectors = sectors;
4434 	if (mddev->pers) {
4435 		set_capacity(mddev->gendisk, mddev->array_sectors);
4436 		revalidate_disk(mddev->gendisk);
4437 	}
4438 	return len;
4439 }
4440 
4441 static struct md_sysfs_entry md_array_size =
4442 __ATTR(array_size, S_IRUGO|S_IWUSR, array_size_show,
4443        array_size_store);
4444 
4445 static struct attribute *md_default_attrs[] = {
4446 	&md_level.attr,
4447 	&md_layout.attr,
4448 	&md_raid_disks.attr,
4449 	&md_chunk_size.attr,
4450 	&md_size.attr,
4451 	&md_resync_start.attr,
4452 	&md_metadata.attr,
4453 	&md_new_device.attr,
4454 	&md_safe_delay.attr,
4455 	&md_array_state.attr,
4456 	&md_reshape_position.attr,
4457 	&md_array_size.attr,
4458 	&max_corr_read_errors.attr,
4459 	NULL,
4460 };
4461 
4462 static struct attribute *md_redundancy_attrs[] = {
4463 	&md_scan_mode.attr,
4464 	&md_mismatches.attr,
4465 	&md_sync_min.attr,
4466 	&md_sync_max.attr,
4467 	&md_sync_speed.attr,
4468 	&md_sync_force_parallel.attr,
4469 	&md_sync_completed.attr,
4470 	&md_min_sync.attr,
4471 	&md_max_sync.attr,
4472 	&md_suspend_lo.attr,
4473 	&md_suspend_hi.attr,
4474 	&md_bitmap.attr,
4475 	&md_degraded.attr,
4476 	NULL,
4477 };
4478 static struct attribute_group md_redundancy_group = {
4479 	.name = NULL,
4480 	.attrs = md_redundancy_attrs,
4481 };
4482 
4483 
4484 static ssize_t
4485 md_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
4486 {
4487 	struct md_sysfs_entry *entry = container_of(attr, struct md_sysfs_entry, attr);
4488 	struct mddev *mddev = container_of(kobj, struct mddev, kobj);
4489 	ssize_t rv;
4490 
4491 	if (!entry->show)
4492 		return -EIO;
4493 	spin_lock(&all_mddevs_lock);
4494 	if (list_empty(&mddev->all_mddevs)) {
4495 		spin_unlock(&all_mddevs_lock);
4496 		return -EBUSY;
4497 	}
4498 	mddev_get(mddev);
4499 	spin_unlock(&all_mddevs_lock);
4500 
4501 	rv = mddev_lock(mddev);
4502 	if (!rv) {
4503 		rv = entry->show(mddev, page);
4504 		mddev_unlock(mddev);
4505 	}
4506 	mddev_put(mddev);
4507 	return rv;
4508 }
4509 
4510 static ssize_t
4511 md_attr_store(struct kobject *kobj, struct attribute *attr,
4512 	      const char *page, size_t length)
4513 {
4514 	struct md_sysfs_entry *entry = container_of(attr, struct md_sysfs_entry, attr);
4515 	struct mddev *mddev = container_of(kobj, struct mddev, kobj);
4516 	ssize_t rv;
4517 
4518 	if (!entry->store)
4519 		return -EIO;
4520 	if (!capable(CAP_SYS_ADMIN))
4521 		return -EACCES;
4522 	spin_lock(&all_mddevs_lock);
4523 	if (list_empty(&mddev->all_mddevs)) {
4524 		spin_unlock(&all_mddevs_lock);
4525 		return -EBUSY;
4526 	}
4527 	mddev_get(mddev);
4528 	spin_unlock(&all_mddevs_lock);
4529 	rv = mddev_lock(mddev);
4530 	if (!rv) {
4531 		rv = entry->store(mddev, page, length);
4532 		mddev_unlock(mddev);
4533 	}
4534 	mddev_put(mddev);
4535 	return rv;
4536 }
4537 
4538 static void md_free(struct kobject *ko)
4539 {
4540 	struct mddev *mddev = container_of(ko, struct mddev, kobj);
4541 
4542 	if (mddev->sysfs_state)
4543 		sysfs_put(mddev->sysfs_state);
4544 
4545 	if (mddev->gendisk) {
4546 		del_gendisk(mddev->gendisk);
4547 		put_disk(mddev->gendisk);
4548 	}
4549 	if (mddev->queue)
4550 		blk_cleanup_queue(mddev->queue);
4551 
4552 	kfree(mddev);
4553 }
4554 
4555 static const struct sysfs_ops md_sysfs_ops = {
4556 	.show	= md_attr_show,
4557 	.store	= md_attr_store,
4558 };
4559 static struct kobj_type md_ktype = {
4560 	.release	= md_free,
4561 	.sysfs_ops	= &md_sysfs_ops,
4562 	.default_attrs	= md_default_attrs,
4563 };
4564 
4565 int mdp_major = 0;
4566 
4567 static void mddev_delayed_delete(struct work_struct *ws)
4568 {
4569 	struct mddev *mddev = container_of(ws, struct mddev, del_work);
4570 
4571 	sysfs_remove_group(&mddev->kobj, &md_bitmap_group);
4572 	kobject_del(&mddev->kobj);
4573 	kobject_put(&mddev->kobj);
4574 }
4575 
4576 static int md_alloc(dev_t dev, char *name)
4577 {
4578 	static DEFINE_MUTEX(disks_mutex);
4579 	struct mddev *mddev = mddev_find(dev);
4580 	struct gendisk *disk;
4581 	int partitioned;
4582 	int shift;
4583 	int unit;
4584 	int error;
4585 
4586 	if (!mddev)
4587 		return -ENODEV;
4588 
4589 	partitioned = (MAJOR(mddev->unit) != MD_MAJOR);
4590 	shift = partitioned ? MdpMinorShift : 0;
4591 	unit = MINOR(mddev->unit) >> shift;
4592 
4593 	/* wait for any previous instance of this device to be
4594 	 * completely removed (mddev_delayed_delete).
4595 	 */
4596 	flush_workqueue(md_misc_wq);
4597 
4598 	mutex_lock(&disks_mutex);
4599 	error = -EEXIST;
4600 	if (mddev->gendisk)
4601 		goto abort;
4602 
4603 	if (name) {
4604 		/* Need to ensure that 'name' is not a duplicate.
4605 		 */
4606 		struct mddev *mddev2;
4607 		spin_lock(&all_mddevs_lock);
4608 
4609 		list_for_each_entry(mddev2, &all_mddevs, all_mddevs)
4610 			if (mddev2->gendisk &&
4611 			    strcmp(mddev2->gendisk->disk_name, name) == 0) {
4612 				spin_unlock(&all_mddevs_lock);
4613 				goto abort;
4614 			}
4615 		spin_unlock(&all_mddevs_lock);
4616 	}
4617 
4618 	error = -ENOMEM;
4619 	mddev->queue = blk_alloc_queue(GFP_KERNEL);
4620 	if (!mddev->queue)
4621 		goto abort;
4622 	mddev->queue->queuedata = mddev;
4623 
4624 	blk_queue_make_request(mddev->queue, md_make_request);
4625 
4626 	disk = alloc_disk(1 << shift);
4627 	if (!disk) {
4628 		blk_cleanup_queue(mddev->queue);
4629 		mddev->queue = NULL;
4630 		goto abort;
4631 	}
4632 	disk->major = MAJOR(mddev->unit);
4633 	disk->first_minor = unit << shift;
4634 	if (name)
4635 		strcpy(disk->disk_name, name);
4636 	else if (partitioned)
4637 		sprintf(disk->disk_name, "md_d%d", unit);
4638 	else
4639 		sprintf(disk->disk_name, "md%d", unit);
4640 	disk->fops = &md_fops;
4641 	disk->private_data = mddev;
4642 	disk->queue = mddev->queue;
4643 	blk_queue_flush(mddev->queue, REQ_FLUSH | REQ_FUA);
4644 	/* Allow extended partitions.  This makes the
4645 	 * 'mdp' device redundant, but we can't really
4646 	 * remove it now.
4647 	 */
4648 	disk->flags |= GENHD_FL_EXT_DEVT;
4649 	mddev->gendisk = disk;
4650 	/* As soon as we call add_disk(), another thread could get
4651 	 * through to md_open, so make sure it doesn't get too far
4652 	 */
4653 	mutex_lock(&mddev->open_mutex);
4654 	add_disk(disk);
4655 
4656 	error = kobject_init_and_add(&mddev->kobj, &md_ktype,
4657 				     &disk_to_dev(disk)->kobj, "%s", "md");
4658 	if (error) {
4659 		/* This isn't possible, but as kobject_init_and_add is marked
4660 		 * __must_check, we must do something with the result
4661 		 */
4662 		printk(KERN_WARNING "md: cannot register %s/md - name in use\n",
4663 		       disk->disk_name);
4664 		error = 0;
4665 	}
4666 	if (mddev->kobj.sd &&
4667 	    sysfs_create_group(&mddev->kobj, &md_bitmap_group))
4668 		printk(KERN_DEBUG "pointless warning\n");
4669 	mutex_unlock(&mddev->open_mutex);
4670  abort:
4671 	mutex_unlock(&disks_mutex);
4672 	if (!error && mddev->kobj.sd) {
4673 		kobject_uevent(&mddev->kobj, KOBJ_ADD);
4674 		mddev->sysfs_state = sysfs_get_dirent_safe(mddev->kobj.sd, "array_state");
4675 	}
4676 	mddev_put(mddev);
4677 	return error;
4678 }
4679 
4680 static struct kobject *md_probe(dev_t dev, int *part, void *data)
4681 {
4682 	md_alloc(dev, NULL);
4683 	return NULL;
4684 }
4685 
4686 static int add_named_array(const char *val, struct kernel_param *kp)
4687 {
4688 	/* val must be "md_*" where * is not all digits.
4689 	 * We allocate an array with a large free minor number, and
4690 	 * set the name to val.  val must not already be an active name.
4691 	 */
4692 	int len = strlen(val);
4693 	char buf[DISK_NAME_LEN];
4694 
4695 	while (len && val[len-1] == '\n')
4696 		len--;
4697 	if (len >= DISK_NAME_LEN)
4698 		return -E2BIG;
4699 	strlcpy(buf, val, len+1);
4700 	if (strncmp(buf, "md_", 3) != 0)
4701 		return -EINVAL;
4702 	return md_alloc(0, buf);
4703 }
4704 
4705 static void md_safemode_timeout(unsigned long data)
4706 {
4707 	struct mddev *mddev = (struct mddev *) data;
4708 
4709 	if (!atomic_read(&mddev->writes_pending)) {
4710 		mddev->safemode = 1;
4711 		if (mddev->external)
4712 			sysfs_notify_dirent_safe(mddev->sysfs_state);
4713 	}
4714 	md_wakeup_thread(mddev->thread);
4715 }
4716 
4717 static int start_dirty_degraded;
4718 
4719 int md_run(struct mddev *mddev)
4720 {
4721 	int err;
4722 	struct md_rdev *rdev;
4723 	struct md_personality *pers;
4724 
4725 	if (list_empty(&mddev->disks))
4726 		/* cannot run an array with no devices.. */
4727 		return -EINVAL;
4728 
4729 	if (mddev->pers)
4730 		return -EBUSY;
4731 	/* Cannot run until previous stop completes properly */
4732 	if (mddev->sysfs_active)
4733 		return -EBUSY;
4734 
4735 	/*
4736 	 * Analyze all RAID superblock(s)
4737 	 */
4738 	if (!mddev->raid_disks) {
4739 		if (!mddev->persistent)
4740 			return -EINVAL;
4741 		analyze_sbs(mddev);
4742 	}
4743 
4744 	if (mddev->level != LEVEL_NONE)
4745 		request_module("md-level-%d", mddev->level);
4746 	else if (mddev->clevel[0])
4747 		request_module("md-%s", mddev->clevel);
4748 
4749 	/*
4750 	 * Drop all container device buffers, from now on
4751 	 * the only valid external interface is through the md
4752 	 * device.
4753 	 */
4754 	list_for_each_entry(rdev, &mddev->disks, same_set) {
4755 		if (test_bit(Faulty, &rdev->flags))
4756 			continue;
4757 		sync_blockdev(rdev->bdev);
4758 		invalidate_bdev(rdev->bdev);
4759 
4760 		/* perform some consistency tests on the device.
4761 		 * We don't want the data to overlap the metadata,
4762 		 * Internal Bitmap issues have been handled elsewhere.
4763 		 */
4764 		if (rdev->meta_bdev) {
4765 			/* Nothing to check */;
4766 		} else if (rdev->data_offset < rdev->sb_start) {
4767 			if (mddev->dev_sectors &&
4768 			    rdev->data_offset + mddev->dev_sectors
4769 			    > rdev->sb_start) {
4770 				printk("md: %s: data overlaps metadata\n",
4771 				       mdname(mddev));
4772 				return -EINVAL;
4773 			}
4774 		} else {
4775 			if (rdev->sb_start + rdev->sb_size/512
4776 			    > rdev->data_offset) {
4777 				printk("md: %s: metadata overlaps data\n",
4778 				       mdname(mddev));
4779 				return -EINVAL;
4780 			}
4781 		}
4782 		sysfs_notify_dirent_safe(rdev->sysfs_state);
4783 	}
4784 
4785 	if (mddev->bio_set == NULL)
4786 		mddev->bio_set = bioset_create(BIO_POOL_SIZE,
4787 					       sizeof(struct mddev *));
4788 
4789 	spin_lock(&pers_lock);
4790 	pers = find_pers(mddev->level, mddev->clevel);
4791 	if (!pers || !try_module_get(pers->owner)) {
4792 		spin_unlock(&pers_lock);
4793 		if (mddev->level != LEVEL_NONE)
4794 			printk(KERN_WARNING "md: personality for level %d is not loaded!\n",
4795 			       mddev->level);
4796 		else
4797 			printk(KERN_WARNING "md: personality for level %s is not loaded!\n",
4798 			       mddev->clevel);
4799 		return -EINVAL;
4800 	}
4801 	mddev->pers = pers;
4802 	spin_unlock(&pers_lock);
4803 	if (mddev->level != pers->level) {
4804 		mddev->level = pers->level;
4805 		mddev->new_level = pers->level;
4806 	}
4807 	strlcpy(mddev->clevel, pers->name, sizeof(mddev->clevel));
4808 
4809 	if (mddev->reshape_position != MaxSector &&
4810 	    pers->start_reshape == NULL) {
4811 		/* This personality cannot handle reshaping... */
4812 		mddev->pers = NULL;
4813 		module_put(pers->owner);
4814 		return -EINVAL;
4815 	}
4816 
4817 	if (pers->sync_request) {
4818 		/* Warn if this is a potentially silly
4819 		 * configuration.
4820 		 */
4821 		char b[BDEVNAME_SIZE], b2[BDEVNAME_SIZE];
4822 		struct md_rdev *rdev2;
4823 		int warned = 0;
4824 
4825 		list_for_each_entry(rdev, &mddev->disks, same_set)
4826 			list_for_each_entry(rdev2, &mddev->disks, same_set) {
4827 				if (rdev < rdev2 &&
4828 				    rdev->bdev->bd_contains ==
4829 				    rdev2->bdev->bd_contains) {
4830 					printk(KERN_WARNING
4831 					       "%s: WARNING: %s appears to be"
4832 					       " on the same physical disk as"
4833 					       " %s.\n",
4834 					       mdname(mddev),
4835 					       bdevname(rdev->bdev,b),
4836 					       bdevname(rdev2->bdev,b2));
4837 					warned = 1;
4838 				}
4839 			}
4840 
4841 		if (warned)
4842 			printk(KERN_WARNING
4843 			       "True protection against single-disk"
4844 			       " failure might be compromised.\n");
4845 	}
4846 
4847 	mddev->recovery = 0;
4848 	/* may be over-ridden by personality */
4849 	mddev->resync_max_sectors = mddev->dev_sectors;
4850 
4851 	mddev->ok_start_degraded = start_dirty_degraded;
4852 
4853 	if (start_readonly && mddev->ro == 0)
4854 		mddev->ro = 2; /* read-only, but switch on first write */
4855 
4856 	err = mddev->pers->run(mddev);
4857 	if (err)
4858 		printk(KERN_ERR "md: pers->run() failed ...\n");
4859 	else if (mddev->pers->size(mddev, 0, 0) < mddev->array_sectors) {
4860 		WARN_ONCE(!mddev->external_size, "%s: default size too small,"
4861 			  " but 'external_size' not in effect?\n", __func__);
4862 		printk(KERN_ERR
4863 		       "md: invalid array_size %llu > default size %llu\n",
4864 		       (unsigned long long)mddev->array_sectors / 2,
4865 		       (unsigned long long)mddev->pers->size(mddev, 0, 0) / 2);
4866 		err = -EINVAL;
4867 		mddev->pers->stop(mddev);
4868 	}
4869 	if (err == 0 && mddev->pers->sync_request) {
4870 		err = bitmap_create(mddev);
4871 		if (err) {
4872 			printk(KERN_ERR "%s: failed to create bitmap (%d)\n",
4873 			       mdname(mddev), err);
4874 			mddev->pers->stop(mddev);
4875 		}
4876 	}
4877 	if (err) {
4878 		module_put(mddev->pers->owner);
4879 		mddev->pers = NULL;
4880 		bitmap_destroy(mddev);
4881 		return err;
4882 	}
4883 	if (mddev->pers->sync_request) {
4884 		if (mddev->kobj.sd &&
4885 		    sysfs_create_group(&mddev->kobj, &md_redundancy_group))
4886 			printk(KERN_WARNING
4887 			       "md: cannot register extra attributes for %s\n",
4888 			       mdname(mddev));
4889 		mddev->sysfs_action = sysfs_get_dirent_safe(mddev->kobj.sd, "sync_action");
4890 	} else if (mddev->ro == 2) /* auto-readonly not meaningful */
4891 		mddev->ro = 0;
4892 
4893  	atomic_set(&mddev->writes_pending,0);
4894 	atomic_set(&mddev->max_corr_read_errors,
4895 		   MD_DEFAULT_MAX_CORRECTED_READ_ERRORS);
4896 	mddev->safemode = 0;
4897 	mddev->safemode_timer.function = md_safemode_timeout;
4898 	mddev->safemode_timer.data = (unsigned long) mddev;
4899 	mddev->safemode_delay = (200 * HZ)/1000 +1; /* 200 msec delay */
4900 	mddev->in_sync = 1;
4901 	smp_wmb();
4902 	mddev->ready = 1;
4903 	list_for_each_entry(rdev, &mddev->disks, same_set)
4904 		if (rdev->raid_disk >= 0)
4905 			if (sysfs_link_rdev(mddev, rdev))
4906 				/* failure here is OK */;
4907 
4908 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
4909 
4910 	if (mddev->flags)
4911 		md_update_sb(mddev, 0);
4912 
4913 	md_new_event(mddev);
4914 	sysfs_notify_dirent_safe(mddev->sysfs_state);
4915 	sysfs_notify_dirent_safe(mddev->sysfs_action);
4916 	sysfs_notify(&mddev->kobj, NULL, "degraded");
4917 	return 0;
4918 }
4919 EXPORT_SYMBOL_GPL(md_run);
4920 
4921 static int do_md_run(struct mddev *mddev)
4922 {
4923 	int err;
4924 
4925 	err = md_run(mddev);
4926 	if (err)
4927 		goto out;
4928 	err = bitmap_load(mddev);
4929 	if (err) {
4930 		bitmap_destroy(mddev);
4931 		goto out;
4932 	}
4933 
4934 	md_wakeup_thread(mddev->thread);
4935 	md_wakeup_thread(mddev->sync_thread); /* possibly kick off a reshape */
4936 
4937 	set_capacity(mddev->gendisk, mddev->array_sectors);
4938 	revalidate_disk(mddev->gendisk);
4939 	mddev->changed = 1;
4940 	kobject_uevent(&disk_to_dev(mddev->gendisk)->kobj, KOBJ_CHANGE);
4941 out:
4942 	return err;
4943 }
4944 
4945 static int restart_array(struct mddev *mddev)
4946 {
4947 	struct gendisk *disk = mddev->gendisk;
4948 
4949 	/* Complain if it has no devices */
4950 	if (list_empty(&mddev->disks))
4951 		return -ENXIO;
4952 	if (!mddev->pers)
4953 		return -EINVAL;
4954 	if (!mddev->ro)
4955 		return -EBUSY;
4956 	mddev->safemode = 0;
4957 	mddev->ro = 0;
4958 	set_disk_ro(disk, 0);
4959 	printk(KERN_INFO "md: %s switched to read-write mode.\n",
4960 		mdname(mddev));
4961 	/* Kick recovery or resync if necessary */
4962 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
4963 	md_wakeup_thread(mddev->thread);
4964 	md_wakeup_thread(mddev->sync_thread);
4965 	sysfs_notify_dirent_safe(mddev->sysfs_state);
4966 	return 0;
4967 }
4968 
4969 /* similar to deny_write_access, but accounts for our holding a reference
4970  * to the file ourselves */
4971 static int deny_bitmap_write_access(struct file * file)
4972 {
4973 	struct inode *inode = file->f_mapping->host;
4974 
4975 	spin_lock(&inode->i_lock);
4976 	if (atomic_read(&inode->i_writecount) > 1) {
4977 		spin_unlock(&inode->i_lock);
4978 		return -ETXTBSY;
4979 	}
4980 	atomic_set(&inode->i_writecount, -1);
4981 	spin_unlock(&inode->i_lock);
4982 
4983 	return 0;
4984 }
4985 
4986 void restore_bitmap_write_access(struct file *file)
4987 {
4988 	struct inode *inode = file->f_mapping->host;
4989 
4990 	spin_lock(&inode->i_lock);
4991 	atomic_set(&inode->i_writecount, 1);
4992 	spin_unlock(&inode->i_lock);
4993 }
4994 
4995 static void md_clean(struct mddev *mddev)
4996 {
4997 	mddev->array_sectors = 0;
4998 	mddev->external_size = 0;
4999 	mddev->dev_sectors = 0;
5000 	mddev->raid_disks = 0;
5001 	mddev->recovery_cp = 0;
5002 	mddev->resync_min = 0;
5003 	mddev->resync_max = MaxSector;
5004 	mddev->reshape_position = MaxSector;
5005 	mddev->external = 0;
5006 	mddev->persistent = 0;
5007 	mddev->level = LEVEL_NONE;
5008 	mddev->clevel[0] = 0;
5009 	mddev->flags = 0;
5010 	mddev->ro = 0;
5011 	mddev->metadata_type[0] = 0;
5012 	mddev->chunk_sectors = 0;
5013 	mddev->ctime = mddev->utime = 0;
5014 	mddev->layout = 0;
5015 	mddev->max_disks = 0;
5016 	mddev->events = 0;
5017 	mddev->can_decrease_events = 0;
5018 	mddev->delta_disks = 0;
5019 	mddev->new_level = LEVEL_NONE;
5020 	mddev->new_layout = 0;
5021 	mddev->new_chunk_sectors = 0;
5022 	mddev->curr_resync = 0;
5023 	mddev->resync_mismatches = 0;
5024 	mddev->suspend_lo = mddev->suspend_hi = 0;
5025 	mddev->sync_speed_min = mddev->sync_speed_max = 0;
5026 	mddev->recovery = 0;
5027 	mddev->in_sync = 0;
5028 	mddev->changed = 0;
5029 	mddev->degraded = 0;
5030 	mddev->safemode = 0;
5031 	mddev->bitmap_info.offset = 0;
5032 	mddev->bitmap_info.default_offset = 0;
5033 	mddev->bitmap_info.chunksize = 0;
5034 	mddev->bitmap_info.daemon_sleep = 0;
5035 	mddev->bitmap_info.max_write_behind = 0;
5036 }
5037 
5038 static void __md_stop_writes(struct mddev *mddev)
5039 {
5040 	if (mddev->sync_thread) {
5041 		set_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
5042 		set_bit(MD_RECOVERY_INTR, &mddev->recovery);
5043 		reap_sync_thread(mddev);
5044 	}
5045 
5046 	del_timer_sync(&mddev->safemode_timer);
5047 
5048 	bitmap_flush(mddev);
5049 	md_super_wait(mddev);
5050 
5051 	if (!mddev->in_sync || mddev->flags) {
5052 		/* mark array as shutdown cleanly */
5053 		mddev->in_sync = 1;
5054 		md_update_sb(mddev, 1);
5055 	}
5056 }
5057 
5058 void md_stop_writes(struct mddev *mddev)
5059 {
5060 	mddev_lock(mddev);
5061 	__md_stop_writes(mddev);
5062 	mddev_unlock(mddev);
5063 }
5064 EXPORT_SYMBOL_GPL(md_stop_writes);
5065 
5066 void md_stop(struct mddev *mddev)
5067 {
5068 	mddev->ready = 0;
5069 	mddev->pers->stop(mddev);
5070 	if (mddev->pers->sync_request && mddev->to_remove == NULL)
5071 		mddev->to_remove = &md_redundancy_group;
5072 	module_put(mddev->pers->owner);
5073 	mddev->pers = NULL;
5074 	clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
5075 }
5076 EXPORT_SYMBOL_GPL(md_stop);
5077 
5078 static int md_set_readonly(struct mddev *mddev, int is_open)
5079 {
5080 	int err = 0;
5081 	mutex_lock(&mddev->open_mutex);
5082 	if (atomic_read(&mddev->openers) > is_open) {
5083 		printk("md: %s still in use.\n",mdname(mddev));
5084 		err = -EBUSY;
5085 		goto out;
5086 	}
5087 	if (mddev->pers) {
5088 		__md_stop_writes(mddev);
5089 
5090 		err  = -ENXIO;
5091 		if (mddev->ro==1)
5092 			goto out;
5093 		mddev->ro = 1;
5094 		set_disk_ro(mddev->gendisk, 1);
5095 		clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
5096 		sysfs_notify_dirent_safe(mddev->sysfs_state);
5097 		err = 0;
5098 	}
5099 out:
5100 	mutex_unlock(&mddev->open_mutex);
5101 	return err;
5102 }
5103 
5104 /* mode:
5105  *   0 - completely stop and dis-assemble array
5106  *   2 - stop but do not disassemble array
5107  */
5108 static int do_md_stop(struct mddev * mddev, int mode, int is_open)
5109 {
5110 	struct gendisk *disk = mddev->gendisk;
5111 	struct md_rdev *rdev;
5112 
5113 	mutex_lock(&mddev->open_mutex);
5114 	if (atomic_read(&mddev->openers) > is_open ||
5115 	    mddev->sysfs_active) {
5116 		printk("md: %s still in use.\n",mdname(mddev));
5117 		mutex_unlock(&mddev->open_mutex);
5118 		return -EBUSY;
5119 	}
5120 
5121 	if (mddev->pers) {
5122 		if (mddev->ro)
5123 			set_disk_ro(disk, 0);
5124 
5125 		__md_stop_writes(mddev);
5126 		md_stop(mddev);
5127 		mddev->queue->merge_bvec_fn = NULL;
5128 		mddev->queue->backing_dev_info.congested_fn = NULL;
5129 
5130 		/* tell userspace to handle 'inactive' */
5131 		sysfs_notify_dirent_safe(mddev->sysfs_state);
5132 
5133 		list_for_each_entry(rdev, &mddev->disks, same_set)
5134 			if (rdev->raid_disk >= 0)
5135 				sysfs_unlink_rdev(mddev, rdev);
5136 
5137 		set_capacity(disk, 0);
5138 		mutex_unlock(&mddev->open_mutex);
5139 		mddev->changed = 1;
5140 		revalidate_disk(disk);
5141 
5142 		if (mddev->ro)
5143 			mddev->ro = 0;
5144 	} else
5145 		mutex_unlock(&mddev->open_mutex);
5146 	/*
5147 	 * Free resources if final stop
5148 	 */
5149 	if (mode == 0) {
5150 		printk(KERN_INFO "md: %s stopped.\n", mdname(mddev));
5151 
5152 		bitmap_destroy(mddev);
5153 		if (mddev->bitmap_info.file) {
5154 			restore_bitmap_write_access(mddev->bitmap_info.file);
5155 			fput(mddev->bitmap_info.file);
5156 			mddev->bitmap_info.file = NULL;
5157 		}
5158 		mddev->bitmap_info.offset = 0;
5159 
5160 		export_array(mddev);
5161 
5162 		md_clean(mddev);
5163 		kobject_uevent(&disk_to_dev(mddev->gendisk)->kobj, KOBJ_CHANGE);
5164 		if (mddev->hold_active == UNTIL_STOP)
5165 			mddev->hold_active = 0;
5166 	}
5167 	blk_integrity_unregister(disk);
5168 	md_new_event(mddev);
5169 	sysfs_notify_dirent_safe(mddev->sysfs_state);
5170 	return 0;
5171 }
5172 
5173 #ifndef MODULE
5174 static void autorun_array(struct mddev *mddev)
5175 {
5176 	struct md_rdev *rdev;
5177 	int err;
5178 
5179 	if (list_empty(&mddev->disks))
5180 		return;
5181 
5182 	printk(KERN_INFO "md: running: ");
5183 
5184 	list_for_each_entry(rdev, &mddev->disks, same_set) {
5185 		char b[BDEVNAME_SIZE];
5186 		printk("<%s>", bdevname(rdev->bdev,b));
5187 	}
5188 	printk("\n");
5189 
5190 	err = do_md_run(mddev);
5191 	if (err) {
5192 		printk(KERN_WARNING "md: do_md_run() returned %d\n", err);
5193 		do_md_stop(mddev, 0, 0);
5194 	}
5195 }
5196 
5197 /*
5198  * lets try to run arrays based on all disks that have arrived
5199  * until now. (those are in pending_raid_disks)
5200  *
5201  * the method: pick the first pending disk, collect all disks with
5202  * the same UUID, remove all from the pending list and put them into
5203  * the 'same_array' list. Then order this list based on superblock
5204  * update time (freshest comes first), kick out 'old' disks and
5205  * compare superblocks. If everything's fine then run it.
5206  *
5207  * If "unit" is allocated, then bump its reference count
5208  */
5209 static void autorun_devices(int part)
5210 {
5211 	struct md_rdev *rdev0, *rdev, *tmp;
5212 	struct mddev *mddev;
5213 	char b[BDEVNAME_SIZE];
5214 
5215 	printk(KERN_INFO "md: autorun ...\n");
5216 	while (!list_empty(&pending_raid_disks)) {
5217 		int unit;
5218 		dev_t dev;
5219 		LIST_HEAD(candidates);
5220 		rdev0 = list_entry(pending_raid_disks.next,
5221 					 struct md_rdev, same_set);
5222 
5223 		printk(KERN_INFO "md: considering %s ...\n",
5224 			bdevname(rdev0->bdev,b));
5225 		INIT_LIST_HEAD(&candidates);
5226 		rdev_for_each_list(rdev, tmp, &pending_raid_disks)
5227 			if (super_90_load(rdev, rdev0, 0) >= 0) {
5228 				printk(KERN_INFO "md:  adding %s ...\n",
5229 					bdevname(rdev->bdev,b));
5230 				list_move(&rdev->same_set, &candidates);
5231 			}
5232 		/*
5233 		 * now we have a set of devices, with all of them having
5234 		 * mostly sane superblocks. It's time to allocate the
5235 		 * mddev.
5236 		 */
5237 		if (part) {
5238 			dev = MKDEV(mdp_major,
5239 				    rdev0->preferred_minor << MdpMinorShift);
5240 			unit = MINOR(dev) >> MdpMinorShift;
5241 		} else {
5242 			dev = MKDEV(MD_MAJOR, rdev0->preferred_minor);
5243 			unit = MINOR(dev);
5244 		}
5245 		if (rdev0->preferred_minor != unit) {
5246 			printk(KERN_INFO "md: unit number in %s is bad: %d\n",
5247 			       bdevname(rdev0->bdev, b), rdev0->preferred_minor);
5248 			break;
5249 		}
5250 
5251 		md_probe(dev, NULL, NULL);
5252 		mddev = mddev_find(dev);
5253 		if (!mddev || !mddev->gendisk) {
5254 			if (mddev)
5255 				mddev_put(mddev);
5256 			printk(KERN_ERR
5257 				"md: cannot allocate memory for md drive.\n");
5258 			break;
5259 		}
5260 		if (mddev_lock(mddev))
5261 			printk(KERN_WARNING "md: %s locked, cannot run\n",
5262 			       mdname(mddev));
5263 		else if (mddev->raid_disks || mddev->major_version
5264 			 || !list_empty(&mddev->disks)) {
5265 			printk(KERN_WARNING
5266 				"md: %s already running, cannot run %s\n",
5267 				mdname(mddev), bdevname(rdev0->bdev,b));
5268 			mddev_unlock(mddev);
5269 		} else {
5270 			printk(KERN_INFO "md: created %s\n", mdname(mddev));
5271 			mddev->persistent = 1;
5272 			rdev_for_each_list(rdev, tmp, &candidates) {
5273 				list_del_init(&rdev->same_set);
5274 				if (bind_rdev_to_array(rdev, mddev))
5275 					export_rdev(rdev);
5276 			}
5277 			autorun_array(mddev);
5278 			mddev_unlock(mddev);
5279 		}
5280 		/* on success, candidates will be empty, on error
5281 		 * it won't...
5282 		 */
5283 		rdev_for_each_list(rdev, tmp, &candidates) {
5284 			list_del_init(&rdev->same_set);
5285 			export_rdev(rdev);
5286 		}
5287 		mddev_put(mddev);
5288 	}
5289 	printk(KERN_INFO "md: ... autorun DONE.\n");
5290 }
5291 #endif /* !MODULE */
5292 
5293 static int get_version(void __user * arg)
5294 {
5295 	mdu_version_t ver;
5296 
5297 	ver.major = MD_MAJOR_VERSION;
5298 	ver.minor = MD_MINOR_VERSION;
5299 	ver.patchlevel = MD_PATCHLEVEL_VERSION;
5300 
5301 	if (copy_to_user(arg, &ver, sizeof(ver)))
5302 		return -EFAULT;
5303 
5304 	return 0;
5305 }
5306 
5307 static int get_array_info(struct mddev * mddev, void __user * arg)
5308 {
5309 	mdu_array_info_t info;
5310 	int nr,working,insync,failed,spare;
5311 	struct md_rdev *rdev;
5312 
5313 	nr=working=insync=failed=spare=0;
5314 	list_for_each_entry(rdev, &mddev->disks, same_set) {
5315 		nr++;
5316 		if (test_bit(Faulty, &rdev->flags))
5317 			failed++;
5318 		else {
5319 			working++;
5320 			if (test_bit(In_sync, &rdev->flags))
5321 				insync++;
5322 			else
5323 				spare++;
5324 		}
5325 	}
5326 
5327 	info.major_version = mddev->major_version;
5328 	info.minor_version = mddev->minor_version;
5329 	info.patch_version = MD_PATCHLEVEL_VERSION;
5330 	info.ctime         = mddev->ctime;
5331 	info.level         = mddev->level;
5332 	info.size          = mddev->dev_sectors / 2;
5333 	if (info.size != mddev->dev_sectors / 2) /* overflow */
5334 		info.size = -1;
5335 	info.nr_disks      = nr;
5336 	info.raid_disks    = mddev->raid_disks;
5337 	info.md_minor      = mddev->md_minor;
5338 	info.not_persistent= !mddev->persistent;
5339 
5340 	info.utime         = mddev->utime;
5341 	info.state         = 0;
5342 	if (mddev->in_sync)
5343 		info.state = (1<<MD_SB_CLEAN);
5344 	if (mddev->bitmap && mddev->bitmap_info.offset)
5345 		info.state = (1<<MD_SB_BITMAP_PRESENT);
5346 	info.active_disks  = insync;
5347 	info.working_disks = working;
5348 	info.failed_disks  = failed;
5349 	info.spare_disks   = spare;
5350 
5351 	info.layout        = mddev->layout;
5352 	info.chunk_size    = mddev->chunk_sectors << 9;
5353 
5354 	if (copy_to_user(arg, &info, sizeof(info)))
5355 		return -EFAULT;
5356 
5357 	return 0;
5358 }
5359 
5360 static int get_bitmap_file(struct mddev * mddev, void __user * arg)
5361 {
5362 	mdu_bitmap_file_t *file = NULL; /* too big for stack allocation */
5363 	char *ptr, *buf = NULL;
5364 	int err = -ENOMEM;
5365 
5366 	if (md_allow_write(mddev))
5367 		file = kmalloc(sizeof(*file), GFP_NOIO);
5368 	else
5369 		file = kmalloc(sizeof(*file), GFP_KERNEL);
5370 
5371 	if (!file)
5372 		goto out;
5373 
5374 	/* bitmap disabled, zero the first byte and copy out */
5375 	if (!mddev->bitmap || !mddev->bitmap->file) {
5376 		file->pathname[0] = '\0';
5377 		goto copy_out;
5378 	}
5379 
5380 	buf = kmalloc(sizeof(file->pathname), GFP_KERNEL);
5381 	if (!buf)
5382 		goto out;
5383 
5384 	ptr = d_path(&mddev->bitmap->file->f_path, buf, sizeof(file->pathname));
5385 	if (IS_ERR(ptr))
5386 		goto out;
5387 
5388 	strcpy(file->pathname, ptr);
5389 
5390 copy_out:
5391 	err = 0;
5392 	if (copy_to_user(arg, file, sizeof(*file)))
5393 		err = -EFAULT;
5394 out:
5395 	kfree(buf);
5396 	kfree(file);
5397 	return err;
5398 }
5399 
5400 static int get_disk_info(struct mddev * mddev, void __user * arg)
5401 {
5402 	mdu_disk_info_t info;
5403 	struct md_rdev *rdev;
5404 
5405 	if (copy_from_user(&info, arg, sizeof(info)))
5406 		return -EFAULT;
5407 
5408 	rdev = find_rdev_nr(mddev, info.number);
5409 	if (rdev) {
5410 		info.major = MAJOR(rdev->bdev->bd_dev);
5411 		info.minor = MINOR(rdev->bdev->bd_dev);
5412 		info.raid_disk = rdev->raid_disk;
5413 		info.state = 0;
5414 		if (test_bit(Faulty, &rdev->flags))
5415 			info.state |= (1<<MD_DISK_FAULTY);
5416 		else if (test_bit(In_sync, &rdev->flags)) {
5417 			info.state |= (1<<MD_DISK_ACTIVE);
5418 			info.state |= (1<<MD_DISK_SYNC);
5419 		}
5420 		if (test_bit(WriteMostly, &rdev->flags))
5421 			info.state |= (1<<MD_DISK_WRITEMOSTLY);
5422 	} else {
5423 		info.major = info.minor = 0;
5424 		info.raid_disk = -1;
5425 		info.state = (1<<MD_DISK_REMOVED);
5426 	}
5427 
5428 	if (copy_to_user(arg, &info, sizeof(info)))
5429 		return -EFAULT;
5430 
5431 	return 0;
5432 }
5433 
5434 static int add_new_disk(struct mddev * mddev, mdu_disk_info_t *info)
5435 {
5436 	char b[BDEVNAME_SIZE], b2[BDEVNAME_SIZE];
5437 	struct md_rdev *rdev;
5438 	dev_t dev = MKDEV(info->major,info->minor);
5439 
5440 	if (info->major != MAJOR(dev) || info->minor != MINOR(dev))
5441 		return -EOVERFLOW;
5442 
5443 	if (!mddev->raid_disks) {
5444 		int err;
5445 		/* expecting a device which has a superblock */
5446 		rdev = md_import_device(dev, mddev->major_version, mddev->minor_version);
5447 		if (IS_ERR(rdev)) {
5448 			printk(KERN_WARNING
5449 				"md: md_import_device returned %ld\n",
5450 				PTR_ERR(rdev));
5451 			return PTR_ERR(rdev);
5452 		}
5453 		if (!list_empty(&mddev->disks)) {
5454 			struct md_rdev *rdev0
5455 				= list_entry(mddev->disks.next,
5456 					     struct md_rdev, same_set);
5457 			err = super_types[mddev->major_version]
5458 				.load_super(rdev, rdev0, mddev->minor_version);
5459 			if (err < 0) {
5460 				printk(KERN_WARNING
5461 					"md: %s has different UUID to %s\n",
5462 					bdevname(rdev->bdev,b),
5463 					bdevname(rdev0->bdev,b2));
5464 				export_rdev(rdev);
5465 				return -EINVAL;
5466 			}
5467 		}
5468 		err = bind_rdev_to_array(rdev, mddev);
5469 		if (err)
5470 			export_rdev(rdev);
5471 		return err;
5472 	}
5473 
5474 	/*
5475 	 * add_new_disk can be used once the array is assembled
5476 	 * to add "hot spares".  They must already have a superblock
5477 	 * written
5478 	 */
5479 	if (mddev->pers) {
5480 		int err;
5481 		if (!mddev->pers->hot_add_disk) {
5482 			printk(KERN_WARNING
5483 				"%s: personality does not support diskops!\n",
5484 			       mdname(mddev));
5485 			return -EINVAL;
5486 		}
5487 		if (mddev->persistent)
5488 			rdev = md_import_device(dev, mddev->major_version,
5489 						mddev->minor_version);
5490 		else
5491 			rdev = md_import_device(dev, -1, -1);
5492 		if (IS_ERR(rdev)) {
5493 			printk(KERN_WARNING
5494 				"md: md_import_device returned %ld\n",
5495 				PTR_ERR(rdev));
5496 			return PTR_ERR(rdev);
5497 		}
5498 		/* set saved_raid_disk if appropriate */
5499 		if (!mddev->persistent) {
5500 			if (info->state & (1<<MD_DISK_SYNC)  &&
5501 			    info->raid_disk < mddev->raid_disks) {
5502 				rdev->raid_disk = info->raid_disk;
5503 				set_bit(In_sync, &rdev->flags);
5504 			} else
5505 				rdev->raid_disk = -1;
5506 		} else
5507 			super_types[mddev->major_version].
5508 				validate_super(mddev, rdev);
5509 		if ((info->state & (1<<MD_DISK_SYNC)) &&
5510 		    (!test_bit(In_sync, &rdev->flags) ||
5511 		     rdev->raid_disk != info->raid_disk)) {
5512 			/* This was a hot-add request, but events doesn't
5513 			 * match, so reject it.
5514 			 */
5515 			export_rdev(rdev);
5516 			return -EINVAL;
5517 		}
5518 
5519 		if (test_bit(In_sync, &rdev->flags))
5520 			rdev->saved_raid_disk = rdev->raid_disk;
5521 		else
5522 			rdev->saved_raid_disk = -1;
5523 
5524 		clear_bit(In_sync, &rdev->flags); /* just to be sure */
5525 		if (info->state & (1<<MD_DISK_WRITEMOSTLY))
5526 			set_bit(WriteMostly, &rdev->flags);
5527 		else
5528 			clear_bit(WriteMostly, &rdev->flags);
5529 
5530 		rdev->raid_disk = -1;
5531 		err = bind_rdev_to_array(rdev, mddev);
5532 		if (!err && !mddev->pers->hot_remove_disk) {
5533 			/* If there is hot_add_disk but no hot_remove_disk
5534 			 * then added disks for geometry changes,
5535 			 * and should be added immediately.
5536 			 */
5537 			super_types[mddev->major_version].
5538 				validate_super(mddev, rdev);
5539 			err = mddev->pers->hot_add_disk(mddev, rdev);
5540 			if (err)
5541 				unbind_rdev_from_array(rdev);
5542 		}
5543 		if (err)
5544 			export_rdev(rdev);
5545 		else
5546 			sysfs_notify_dirent_safe(rdev->sysfs_state);
5547 
5548 		md_update_sb(mddev, 1);
5549 		if (mddev->degraded)
5550 			set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
5551 		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
5552 		if (!err)
5553 			md_new_event(mddev);
5554 		md_wakeup_thread(mddev->thread);
5555 		return err;
5556 	}
5557 
5558 	/* otherwise, add_new_disk is only allowed
5559 	 * for major_version==0 superblocks
5560 	 */
5561 	if (mddev->major_version != 0) {
5562 		printk(KERN_WARNING "%s: ADD_NEW_DISK not supported\n",
5563 		       mdname(mddev));
5564 		return -EINVAL;
5565 	}
5566 
5567 	if (!(info->state & (1<<MD_DISK_FAULTY))) {
5568 		int err;
5569 		rdev = md_import_device(dev, -1, 0);
5570 		if (IS_ERR(rdev)) {
5571 			printk(KERN_WARNING
5572 				"md: error, md_import_device() returned %ld\n",
5573 				PTR_ERR(rdev));
5574 			return PTR_ERR(rdev);
5575 		}
5576 		rdev->desc_nr = info->number;
5577 		if (info->raid_disk < mddev->raid_disks)
5578 			rdev->raid_disk = info->raid_disk;
5579 		else
5580 			rdev->raid_disk = -1;
5581 
5582 		if (rdev->raid_disk < mddev->raid_disks)
5583 			if (info->state & (1<<MD_DISK_SYNC))
5584 				set_bit(In_sync, &rdev->flags);
5585 
5586 		if (info->state & (1<<MD_DISK_WRITEMOSTLY))
5587 			set_bit(WriteMostly, &rdev->flags);
5588 
5589 		if (!mddev->persistent) {
5590 			printk(KERN_INFO "md: nonpersistent superblock ...\n");
5591 			rdev->sb_start = i_size_read(rdev->bdev->bd_inode) / 512;
5592 		} else
5593 			rdev->sb_start = calc_dev_sboffset(rdev);
5594 		rdev->sectors = rdev->sb_start;
5595 
5596 		err = bind_rdev_to_array(rdev, mddev);
5597 		if (err) {
5598 			export_rdev(rdev);
5599 			return err;
5600 		}
5601 	}
5602 
5603 	return 0;
5604 }
5605 
5606 static int hot_remove_disk(struct mddev * mddev, dev_t dev)
5607 {
5608 	char b[BDEVNAME_SIZE];
5609 	struct md_rdev *rdev;
5610 
5611 	rdev = find_rdev(mddev, dev);
5612 	if (!rdev)
5613 		return -ENXIO;
5614 
5615 	if (rdev->raid_disk >= 0)
5616 		goto busy;
5617 
5618 	kick_rdev_from_array(rdev);
5619 	md_update_sb(mddev, 1);
5620 	md_new_event(mddev);
5621 
5622 	return 0;
5623 busy:
5624 	printk(KERN_WARNING "md: cannot remove active disk %s from %s ...\n",
5625 		bdevname(rdev->bdev,b), mdname(mddev));
5626 	return -EBUSY;
5627 }
5628 
5629 static int hot_add_disk(struct mddev * mddev, dev_t dev)
5630 {
5631 	char b[BDEVNAME_SIZE];
5632 	int err;
5633 	struct md_rdev *rdev;
5634 
5635 	if (!mddev->pers)
5636 		return -ENODEV;
5637 
5638 	if (mddev->major_version != 0) {
5639 		printk(KERN_WARNING "%s: HOT_ADD may only be used with"
5640 			" version-0 superblocks.\n",
5641 			mdname(mddev));
5642 		return -EINVAL;
5643 	}
5644 	if (!mddev->pers->hot_add_disk) {
5645 		printk(KERN_WARNING
5646 			"%s: personality does not support diskops!\n",
5647 			mdname(mddev));
5648 		return -EINVAL;
5649 	}
5650 
5651 	rdev = md_import_device(dev, -1, 0);
5652 	if (IS_ERR(rdev)) {
5653 		printk(KERN_WARNING
5654 			"md: error, md_import_device() returned %ld\n",
5655 			PTR_ERR(rdev));
5656 		return -EINVAL;
5657 	}
5658 
5659 	if (mddev->persistent)
5660 		rdev->sb_start = calc_dev_sboffset(rdev);
5661 	else
5662 		rdev->sb_start = i_size_read(rdev->bdev->bd_inode) / 512;
5663 
5664 	rdev->sectors = rdev->sb_start;
5665 
5666 	if (test_bit(Faulty, &rdev->flags)) {
5667 		printk(KERN_WARNING
5668 			"md: can not hot-add faulty %s disk to %s!\n",
5669 			bdevname(rdev->bdev,b), mdname(mddev));
5670 		err = -EINVAL;
5671 		goto abort_export;
5672 	}
5673 	clear_bit(In_sync, &rdev->flags);
5674 	rdev->desc_nr = -1;
5675 	rdev->saved_raid_disk = -1;
5676 	err = bind_rdev_to_array(rdev, mddev);
5677 	if (err)
5678 		goto abort_export;
5679 
5680 	/*
5681 	 * The rest should better be atomic, we can have disk failures
5682 	 * noticed in interrupt contexts ...
5683 	 */
5684 
5685 	rdev->raid_disk = -1;
5686 
5687 	md_update_sb(mddev, 1);
5688 
5689 	/*
5690 	 * Kick recovery, maybe this spare has to be added to the
5691 	 * array immediately.
5692 	 */
5693 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
5694 	md_wakeup_thread(mddev->thread);
5695 	md_new_event(mddev);
5696 	return 0;
5697 
5698 abort_export:
5699 	export_rdev(rdev);
5700 	return err;
5701 }
5702 
5703 static int set_bitmap_file(struct mddev *mddev, int fd)
5704 {
5705 	int err;
5706 
5707 	if (mddev->pers) {
5708 		if (!mddev->pers->quiesce)
5709 			return -EBUSY;
5710 		if (mddev->recovery || mddev->sync_thread)
5711 			return -EBUSY;
5712 		/* we should be able to change the bitmap.. */
5713 	}
5714 
5715 
5716 	if (fd >= 0) {
5717 		if (mddev->bitmap)
5718 			return -EEXIST; /* cannot add when bitmap is present */
5719 		mddev->bitmap_info.file = fget(fd);
5720 
5721 		if (mddev->bitmap_info.file == NULL) {
5722 			printk(KERN_ERR "%s: error: failed to get bitmap file\n",
5723 			       mdname(mddev));
5724 			return -EBADF;
5725 		}
5726 
5727 		err = deny_bitmap_write_access(mddev->bitmap_info.file);
5728 		if (err) {
5729 			printk(KERN_ERR "%s: error: bitmap file is already in use\n",
5730 			       mdname(mddev));
5731 			fput(mddev->bitmap_info.file);
5732 			mddev->bitmap_info.file = NULL;
5733 			return err;
5734 		}
5735 		mddev->bitmap_info.offset = 0; /* file overrides offset */
5736 	} else if (mddev->bitmap == NULL)
5737 		return -ENOENT; /* cannot remove what isn't there */
5738 	err = 0;
5739 	if (mddev->pers) {
5740 		mddev->pers->quiesce(mddev, 1);
5741 		if (fd >= 0) {
5742 			err = bitmap_create(mddev);
5743 			if (!err)
5744 				err = bitmap_load(mddev);
5745 		}
5746 		if (fd < 0 || err) {
5747 			bitmap_destroy(mddev);
5748 			fd = -1; /* make sure to put the file */
5749 		}
5750 		mddev->pers->quiesce(mddev, 0);
5751 	}
5752 	if (fd < 0) {
5753 		if (mddev->bitmap_info.file) {
5754 			restore_bitmap_write_access(mddev->bitmap_info.file);
5755 			fput(mddev->bitmap_info.file);
5756 		}
5757 		mddev->bitmap_info.file = NULL;
5758 	}
5759 
5760 	return err;
5761 }
5762 
5763 /*
5764  * set_array_info is used two different ways
5765  * The original usage is when creating a new array.
5766  * In this usage, raid_disks is > 0 and it together with
5767  *  level, size, not_persistent,layout,chunksize determine the
5768  *  shape of the array.
5769  *  This will always create an array with a type-0.90.0 superblock.
5770  * The newer usage is when assembling an array.
5771  *  In this case raid_disks will be 0, and the major_version field is
5772  *  use to determine which style super-blocks are to be found on the devices.
5773  *  The minor and patch _version numbers are also kept incase the
5774  *  super_block handler wishes to interpret them.
5775  */
5776 static int set_array_info(struct mddev * mddev, mdu_array_info_t *info)
5777 {
5778 
5779 	if (info->raid_disks == 0) {
5780 		/* just setting version number for superblock loading */
5781 		if (info->major_version < 0 ||
5782 		    info->major_version >= ARRAY_SIZE(super_types) ||
5783 		    super_types[info->major_version].name == NULL) {
5784 			/* maybe try to auto-load a module? */
5785 			printk(KERN_INFO
5786 				"md: superblock version %d not known\n",
5787 				info->major_version);
5788 			return -EINVAL;
5789 		}
5790 		mddev->major_version = info->major_version;
5791 		mddev->minor_version = info->minor_version;
5792 		mddev->patch_version = info->patch_version;
5793 		mddev->persistent = !info->not_persistent;
5794 		/* ensure mddev_put doesn't delete this now that there
5795 		 * is some minimal configuration.
5796 		 */
5797 		mddev->ctime         = get_seconds();
5798 		return 0;
5799 	}
5800 	mddev->major_version = MD_MAJOR_VERSION;
5801 	mddev->minor_version = MD_MINOR_VERSION;
5802 	mddev->patch_version = MD_PATCHLEVEL_VERSION;
5803 	mddev->ctime         = get_seconds();
5804 
5805 	mddev->level         = info->level;
5806 	mddev->clevel[0]     = 0;
5807 	mddev->dev_sectors   = 2 * (sector_t)info->size;
5808 	mddev->raid_disks    = info->raid_disks;
5809 	/* don't set md_minor, it is determined by which /dev/md* was
5810 	 * openned
5811 	 */
5812 	if (info->state & (1<<MD_SB_CLEAN))
5813 		mddev->recovery_cp = MaxSector;
5814 	else
5815 		mddev->recovery_cp = 0;
5816 	mddev->persistent    = ! info->not_persistent;
5817 	mddev->external	     = 0;
5818 
5819 	mddev->layout        = info->layout;
5820 	mddev->chunk_sectors = info->chunk_size >> 9;
5821 
5822 	mddev->max_disks     = MD_SB_DISKS;
5823 
5824 	if (mddev->persistent)
5825 		mddev->flags         = 0;
5826 	set_bit(MD_CHANGE_DEVS, &mddev->flags);
5827 
5828 	mddev->bitmap_info.default_offset = MD_SB_BYTES >> 9;
5829 	mddev->bitmap_info.offset = 0;
5830 
5831 	mddev->reshape_position = MaxSector;
5832 
5833 	/*
5834 	 * Generate a 128 bit UUID
5835 	 */
5836 	get_random_bytes(mddev->uuid, 16);
5837 
5838 	mddev->new_level = mddev->level;
5839 	mddev->new_chunk_sectors = mddev->chunk_sectors;
5840 	mddev->new_layout = mddev->layout;
5841 	mddev->delta_disks = 0;
5842 
5843 	return 0;
5844 }
5845 
5846 void md_set_array_sectors(struct mddev *mddev, sector_t array_sectors)
5847 {
5848 	WARN(!mddev_is_locked(mddev), "%s: unlocked mddev!\n", __func__);
5849 
5850 	if (mddev->external_size)
5851 		return;
5852 
5853 	mddev->array_sectors = array_sectors;
5854 }
5855 EXPORT_SYMBOL(md_set_array_sectors);
5856 
5857 static int update_size(struct mddev *mddev, sector_t num_sectors)
5858 {
5859 	struct md_rdev *rdev;
5860 	int rv;
5861 	int fit = (num_sectors == 0);
5862 
5863 	if (mddev->pers->resize == NULL)
5864 		return -EINVAL;
5865 	/* The "num_sectors" is the number of sectors of each device that
5866 	 * is used.  This can only make sense for arrays with redundancy.
5867 	 * linear and raid0 always use whatever space is available. We can only
5868 	 * consider changing this number if no resync or reconstruction is
5869 	 * happening, and if the new size is acceptable. It must fit before the
5870 	 * sb_start or, if that is <data_offset, it must fit before the size
5871 	 * of each device.  If num_sectors is zero, we find the largest size
5872 	 * that fits.
5873 	 */
5874 	if (mddev->sync_thread)
5875 		return -EBUSY;
5876 	if (mddev->bitmap)
5877 		/* Sorry, cannot grow a bitmap yet, just remove it,
5878 		 * grow, and re-add.
5879 		 */
5880 		return -EBUSY;
5881 	list_for_each_entry(rdev, &mddev->disks, same_set) {
5882 		sector_t avail = rdev->sectors;
5883 
5884 		if (fit && (num_sectors == 0 || num_sectors > avail))
5885 			num_sectors = avail;
5886 		if (avail < num_sectors)
5887 			return -ENOSPC;
5888 	}
5889 	rv = mddev->pers->resize(mddev, num_sectors);
5890 	if (!rv)
5891 		revalidate_disk(mddev->gendisk);
5892 	return rv;
5893 }
5894 
5895 static int update_raid_disks(struct mddev *mddev, int raid_disks)
5896 {
5897 	int rv;
5898 	/* change the number of raid disks */
5899 	if (mddev->pers->check_reshape == NULL)
5900 		return -EINVAL;
5901 	if (raid_disks <= 0 ||
5902 	    (mddev->max_disks && raid_disks >= mddev->max_disks))
5903 		return -EINVAL;
5904 	if (mddev->sync_thread || mddev->reshape_position != MaxSector)
5905 		return -EBUSY;
5906 	mddev->delta_disks = raid_disks - mddev->raid_disks;
5907 
5908 	rv = mddev->pers->check_reshape(mddev);
5909 	if (rv < 0)
5910 		mddev->delta_disks = 0;
5911 	return rv;
5912 }
5913 
5914 
5915 /*
5916  * update_array_info is used to change the configuration of an
5917  * on-line array.
5918  * The version, ctime,level,size,raid_disks,not_persistent, layout,chunk_size
5919  * fields in the info are checked against the array.
5920  * Any differences that cannot be handled will cause an error.
5921  * Normally, only one change can be managed at a time.
5922  */
5923 static int update_array_info(struct mddev *mddev, mdu_array_info_t *info)
5924 {
5925 	int rv = 0;
5926 	int cnt = 0;
5927 	int state = 0;
5928 
5929 	/* calculate expected state,ignoring low bits */
5930 	if (mddev->bitmap && mddev->bitmap_info.offset)
5931 		state |= (1 << MD_SB_BITMAP_PRESENT);
5932 
5933 	if (mddev->major_version != info->major_version ||
5934 	    mddev->minor_version != info->minor_version ||
5935 /*	    mddev->patch_version != info->patch_version || */
5936 	    mddev->ctime         != info->ctime         ||
5937 	    mddev->level         != info->level         ||
5938 /*	    mddev->layout        != info->layout        || */
5939 	    !mddev->persistent	 != info->not_persistent||
5940 	    mddev->chunk_sectors != info->chunk_size >> 9 ||
5941 	    /* ignore bottom 8 bits of state, and allow SB_BITMAP_PRESENT to change */
5942 	    ((state^info->state) & 0xfffffe00)
5943 		)
5944 		return -EINVAL;
5945 	/* Check there is only one change */
5946 	if (info->size >= 0 && mddev->dev_sectors / 2 != info->size)
5947 		cnt++;
5948 	if (mddev->raid_disks != info->raid_disks)
5949 		cnt++;
5950 	if (mddev->layout != info->layout)
5951 		cnt++;
5952 	if ((state ^ info->state) & (1<<MD_SB_BITMAP_PRESENT))
5953 		cnt++;
5954 	if (cnt == 0)
5955 		return 0;
5956 	if (cnt > 1)
5957 		return -EINVAL;
5958 
5959 	if (mddev->layout != info->layout) {
5960 		/* Change layout
5961 		 * we don't need to do anything at the md level, the
5962 		 * personality will take care of it all.
5963 		 */
5964 		if (mddev->pers->check_reshape == NULL)
5965 			return -EINVAL;
5966 		else {
5967 			mddev->new_layout = info->layout;
5968 			rv = mddev->pers->check_reshape(mddev);
5969 			if (rv)
5970 				mddev->new_layout = mddev->layout;
5971 			return rv;
5972 		}
5973 	}
5974 	if (info->size >= 0 && mddev->dev_sectors / 2 != info->size)
5975 		rv = update_size(mddev, (sector_t)info->size * 2);
5976 
5977 	if (mddev->raid_disks    != info->raid_disks)
5978 		rv = update_raid_disks(mddev, info->raid_disks);
5979 
5980 	if ((state ^ info->state) & (1<<MD_SB_BITMAP_PRESENT)) {
5981 		if (mddev->pers->quiesce == NULL)
5982 			return -EINVAL;
5983 		if (mddev->recovery || mddev->sync_thread)
5984 			return -EBUSY;
5985 		if (info->state & (1<<MD_SB_BITMAP_PRESENT)) {
5986 			/* add the bitmap */
5987 			if (mddev->bitmap)
5988 				return -EEXIST;
5989 			if (mddev->bitmap_info.default_offset == 0)
5990 				return -EINVAL;
5991 			mddev->bitmap_info.offset =
5992 				mddev->bitmap_info.default_offset;
5993 			mddev->pers->quiesce(mddev, 1);
5994 			rv = bitmap_create(mddev);
5995 			if (!rv)
5996 				rv = bitmap_load(mddev);
5997 			if (rv)
5998 				bitmap_destroy(mddev);
5999 			mddev->pers->quiesce(mddev, 0);
6000 		} else {
6001 			/* remove the bitmap */
6002 			if (!mddev->bitmap)
6003 				return -ENOENT;
6004 			if (mddev->bitmap->file)
6005 				return -EINVAL;
6006 			mddev->pers->quiesce(mddev, 1);
6007 			bitmap_destroy(mddev);
6008 			mddev->pers->quiesce(mddev, 0);
6009 			mddev->bitmap_info.offset = 0;
6010 		}
6011 	}
6012 	md_update_sb(mddev, 1);
6013 	return rv;
6014 }
6015 
6016 static int set_disk_faulty(struct mddev *mddev, dev_t dev)
6017 {
6018 	struct md_rdev *rdev;
6019 
6020 	if (mddev->pers == NULL)
6021 		return -ENODEV;
6022 
6023 	rdev = find_rdev(mddev, dev);
6024 	if (!rdev)
6025 		return -ENODEV;
6026 
6027 	md_error(mddev, rdev);
6028 	if (!test_bit(Faulty, &rdev->flags))
6029 		return -EBUSY;
6030 	return 0;
6031 }
6032 
6033 /*
6034  * We have a problem here : there is no easy way to give a CHS
6035  * virtual geometry. We currently pretend that we have a 2 heads
6036  * 4 sectors (with a BIG number of cylinders...). This drives
6037  * dosfs just mad... ;-)
6038  */
6039 static int md_getgeo(struct block_device *bdev, struct hd_geometry *geo)
6040 {
6041 	struct mddev *mddev = bdev->bd_disk->private_data;
6042 
6043 	geo->heads = 2;
6044 	geo->sectors = 4;
6045 	geo->cylinders = mddev->array_sectors / 8;
6046 	return 0;
6047 }
6048 
6049 static int md_ioctl(struct block_device *bdev, fmode_t mode,
6050 			unsigned int cmd, unsigned long arg)
6051 {
6052 	int err = 0;
6053 	void __user *argp = (void __user *)arg;
6054 	struct mddev *mddev = NULL;
6055 	int ro;
6056 
6057 	if (!capable(CAP_SYS_ADMIN))
6058 		return -EACCES;
6059 
6060 	/*
6061 	 * Commands dealing with the RAID driver but not any
6062 	 * particular array:
6063 	 */
6064 	switch (cmd)
6065 	{
6066 		case RAID_VERSION:
6067 			err = get_version(argp);
6068 			goto done;
6069 
6070 		case PRINT_RAID_DEBUG:
6071 			err = 0;
6072 			md_print_devices();
6073 			goto done;
6074 
6075 #ifndef MODULE
6076 		case RAID_AUTORUN:
6077 			err = 0;
6078 			autostart_arrays(arg);
6079 			goto done;
6080 #endif
6081 		default:;
6082 	}
6083 
6084 	/*
6085 	 * Commands creating/starting a new array:
6086 	 */
6087 
6088 	mddev = bdev->bd_disk->private_data;
6089 
6090 	if (!mddev) {
6091 		BUG();
6092 		goto abort;
6093 	}
6094 
6095 	err = mddev_lock(mddev);
6096 	if (err) {
6097 		printk(KERN_INFO
6098 			"md: ioctl lock interrupted, reason %d, cmd %d\n",
6099 			err, cmd);
6100 		goto abort;
6101 	}
6102 
6103 	switch (cmd)
6104 	{
6105 		case SET_ARRAY_INFO:
6106 			{
6107 				mdu_array_info_t info;
6108 				if (!arg)
6109 					memset(&info, 0, sizeof(info));
6110 				else if (copy_from_user(&info, argp, sizeof(info))) {
6111 					err = -EFAULT;
6112 					goto abort_unlock;
6113 				}
6114 				if (mddev->pers) {
6115 					err = update_array_info(mddev, &info);
6116 					if (err) {
6117 						printk(KERN_WARNING "md: couldn't update"
6118 						       " array info. %d\n", err);
6119 						goto abort_unlock;
6120 					}
6121 					goto done_unlock;
6122 				}
6123 				if (!list_empty(&mddev->disks)) {
6124 					printk(KERN_WARNING
6125 					       "md: array %s already has disks!\n",
6126 					       mdname(mddev));
6127 					err = -EBUSY;
6128 					goto abort_unlock;
6129 				}
6130 				if (mddev->raid_disks) {
6131 					printk(KERN_WARNING
6132 					       "md: array %s already initialised!\n",
6133 					       mdname(mddev));
6134 					err = -EBUSY;
6135 					goto abort_unlock;
6136 				}
6137 				err = set_array_info(mddev, &info);
6138 				if (err) {
6139 					printk(KERN_WARNING "md: couldn't set"
6140 					       " array info. %d\n", err);
6141 					goto abort_unlock;
6142 				}
6143 			}
6144 			goto done_unlock;
6145 
6146 		default:;
6147 	}
6148 
6149 	/*
6150 	 * Commands querying/configuring an existing array:
6151 	 */
6152 	/* if we are not initialised yet, only ADD_NEW_DISK, STOP_ARRAY,
6153 	 * RUN_ARRAY, and GET_ and SET_BITMAP_FILE are allowed */
6154 	if ((!mddev->raid_disks && !mddev->external)
6155 	    && cmd != ADD_NEW_DISK && cmd != STOP_ARRAY
6156 	    && cmd != RUN_ARRAY && cmd != SET_BITMAP_FILE
6157 	    && cmd != GET_BITMAP_FILE) {
6158 		err = -ENODEV;
6159 		goto abort_unlock;
6160 	}
6161 
6162 	/*
6163 	 * Commands even a read-only array can execute:
6164 	 */
6165 	switch (cmd)
6166 	{
6167 		case GET_ARRAY_INFO:
6168 			err = get_array_info(mddev, argp);
6169 			goto done_unlock;
6170 
6171 		case GET_BITMAP_FILE:
6172 			err = get_bitmap_file(mddev, argp);
6173 			goto done_unlock;
6174 
6175 		case GET_DISK_INFO:
6176 			err = get_disk_info(mddev, argp);
6177 			goto done_unlock;
6178 
6179 		case RESTART_ARRAY_RW:
6180 			err = restart_array(mddev);
6181 			goto done_unlock;
6182 
6183 		case STOP_ARRAY:
6184 			err = do_md_stop(mddev, 0, 1);
6185 			goto done_unlock;
6186 
6187 		case STOP_ARRAY_RO:
6188 			err = md_set_readonly(mddev, 1);
6189 			goto done_unlock;
6190 
6191 		case BLKROSET:
6192 			if (get_user(ro, (int __user *)(arg))) {
6193 				err = -EFAULT;
6194 				goto done_unlock;
6195 			}
6196 			err = -EINVAL;
6197 
6198 			/* if the bdev is going readonly the value of mddev->ro
6199 			 * does not matter, no writes are coming
6200 			 */
6201 			if (ro)
6202 				goto done_unlock;
6203 
6204 			/* are we are already prepared for writes? */
6205 			if (mddev->ro != 1)
6206 				goto done_unlock;
6207 
6208 			/* transitioning to readauto need only happen for
6209 			 * arrays that call md_write_start
6210 			 */
6211 			if (mddev->pers) {
6212 				err = restart_array(mddev);
6213 				if (err == 0) {
6214 					mddev->ro = 2;
6215 					set_disk_ro(mddev->gendisk, 0);
6216 				}
6217 			}
6218 			goto done_unlock;
6219 	}
6220 
6221 	/*
6222 	 * The remaining ioctls are changing the state of the
6223 	 * superblock, so we do not allow them on read-only arrays.
6224 	 * However non-MD ioctls (e.g. get-size) will still come through
6225 	 * here and hit the 'default' below, so only disallow
6226 	 * 'md' ioctls, and switch to rw mode if started auto-readonly.
6227 	 */
6228 	if (_IOC_TYPE(cmd) == MD_MAJOR && mddev->ro && mddev->pers) {
6229 		if (mddev->ro == 2) {
6230 			mddev->ro = 0;
6231 			sysfs_notify_dirent_safe(mddev->sysfs_state);
6232 			set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
6233 			md_wakeup_thread(mddev->thread);
6234 		} else {
6235 			err = -EROFS;
6236 			goto abort_unlock;
6237 		}
6238 	}
6239 
6240 	switch (cmd)
6241 	{
6242 		case ADD_NEW_DISK:
6243 		{
6244 			mdu_disk_info_t info;
6245 			if (copy_from_user(&info, argp, sizeof(info)))
6246 				err = -EFAULT;
6247 			else
6248 				err = add_new_disk(mddev, &info);
6249 			goto done_unlock;
6250 		}
6251 
6252 		case HOT_REMOVE_DISK:
6253 			err = hot_remove_disk(mddev, new_decode_dev(arg));
6254 			goto done_unlock;
6255 
6256 		case HOT_ADD_DISK:
6257 			err = hot_add_disk(mddev, new_decode_dev(arg));
6258 			goto done_unlock;
6259 
6260 		case SET_DISK_FAULTY:
6261 			err = set_disk_faulty(mddev, new_decode_dev(arg));
6262 			goto done_unlock;
6263 
6264 		case RUN_ARRAY:
6265 			err = do_md_run(mddev);
6266 			goto done_unlock;
6267 
6268 		case SET_BITMAP_FILE:
6269 			err = set_bitmap_file(mddev, (int)arg);
6270 			goto done_unlock;
6271 
6272 		default:
6273 			err = -EINVAL;
6274 			goto abort_unlock;
6275 	}
6276 
6277 done_unlock:
6278 abort_unlock:
6279 	if (mddev->hold_active == UNTIL_IOCTL &&
6280 	    err != -EINVAL)
6281 		mddev->hold_active = 0;
6282 	mddev_unlock(mddev);
6283 
6284 	return err;
6285 done:
6286 	if (err)
6287 		MD_BUG();
6288 abort:
6289 	return err;
6290 }
6291 #ifdef CONFIG_COMPAT
6292 static int md_compat_ioctl(struct block_device *bdev, fmode_t mode,
6293 		    unsigned int cmd, unsigned long arg)
6294 {
6295 	switch (cmd) {
6296 	case HOT_REMOVE_DISK:
6297 	case HOT_ADD_DISK:
6298 	case SET_DISK_FAULTY:
6299 	case SET_BITMAP_FILE:
6300 		/* These take in integer arg, do not convert */
6301 		break;
6302 	default:
6303 		arg = (unsigned long)compat_ptr(arg);
6304 		break;
6305 	}
6306 
6307 	return md_ioctl(bdev, mode, cmd, arg);
6308 }
6309 #endif /* CONFIG_COMPAT */
6310 
6311 static int md_open(struct block_device *bdev, fmode_t mode)
6312 {
6313 	/*
6314 	 * Succeed if we can lock the mddev, which confirms that
6315 	 * it isn't being stopped right now.
6316 	 */
6317 	struct mddev *mddev = mddev_find(bdev->bd_dev);
6318 	int err;
6319 
6320 	if (mddev->gendisk != bdev->bd_disk) {
6321 		/* we are racing with mddev_put which is discarding this
6322 		 * bd_disk.
6323 		 */
6324 		mddev_put(mddev);
6325 		/* Wait until bdev->bd_disk is definitely gone */
6326 		flush_workqueue(md_misc_wq);
6327 		/* Then retry the open from the top */
6328 		return -ERESTARTSYS;
6329 	}
6330 	BUG_ON(mddev != bdev->bd_disk->private_data);
6331 
6332 	if ((err = mutex_lock_interruptible(&mddev->open_mutex)))
6333 		goto out;
6334 
6335 	err = 0;
6336 	atomic_inc(&mddev->openers);
6337 	mutex_unlock(&mddev->open_mutex);
6338 
6339 	check_disk_change(bdev);
6340  out:
6341 	return err;
6342 }
6343 
6344 static int md_release(struct gendisk *disk, fmode_t mode)
6345 {
6346  	struct mddev *mddev = disk->private_data;
6347 
6348 	BUG_ON(!mddev);
6349 	atomic_dec(&mddev->openers);
6350 	mddev_put(mddev);
6351 
6352 	return 0;
6353 }
6354 
6355 static int md_media_changed(struct gendisk *disk)
6356 {
6357 	struct mddev *mddev = disk->private_data;
6358 
6359 	return mddev->changed;
6360 }
6361 
6362 static int md_revalidate(struct gendisk *disk)
6363 {
6364 	struct mddev *mddev = disk->private_data;
6365 
6366 	mddev->changed = 0;
6367 	return 0;
6368 }
6369 static const struct block_device_operations md_fops =
6370 {
6371 	.owner		= THIS_MODULE,
6372 	.open		= md_open,
6373 	.release	= md_release,
6374 	.ioctl		= md_ioctl,
6375 #ifdef CONFIG_COMPAT
6376 	.compat_ioctl	= md_compat_ioctl,
6377 #endif
6378 	.getgeo		= md_getgeo,
6379 	.media_changed  = md_media_changed,
6380 	.revalidate_disk= md_revalidate,
6381 };
6382 
6383 static int md_thread(void * arg)
6384 {
6385 	struct md_thread *thread = arg;
6386 
6387 	/*
6388 	 * md_thread is a 'system-thread', it's priority should be very
6389 	 * high. We avoid resource deadlocks individually in each
6390 	 * raid personality. (RAID5 does preallocation) We also use RR and
6391 	 * the very same RT priority as kswapd, thus we will never get
6392 	 * into a priority inversion deadlock.
6393 	 *
6394 	 * we definitely have to have equal or higher priority than
6395 	 * bdflush, otherwise bdflush will deadlock if there are too
6396 	 * many dirty RAID5 blocks.
6397 	 */
6398 
6399 	allow_signal(SIGKILL);
6400 	while (!kthread_should_stop()) {
6401 
6402 		/* We need to wait INTERRUPTIBLE so that
6403 		 * we don't add to the load-average.
6404 		 * That means we need to be sure no signals are
6405 		 * pending
6406 		 */
6407 		if (signal_pending(current))
6408 			flush_signals(current);
6409 
6410 		wait_event_interruptible_timeout
6411 			(thread->wqueue,
6412 			 test_bit(THREAD_WAKEUP, &thread->flags)
6413 			 || kthread_should_stop(),
6414 			 thread->timeout);
6415 
6416 		clear_bit(THREAD_WAKEUP, &thread->flags);
6417 		if (!kthread_should_stop())
6418 			thread->run(thread->mddev);
6419 	}
6420 
6421 	return 0;
6422 }
6423 
6424 void md_wakeup_thread(struct md_thread *thread)
6425 {
6426 	if (thread) {
6427 		pr_debug("md: waking up MD thread %s.\n", thread->tsk->comm);
6428 		set_bit(THREAD_WAKEUP, &thread->flags);
6429 		wake_up(&thread->wqueue);
6430 	}
6431 }
6432 
6433 struct md_thread *md_register_thread(void (*run) (struct mddev *), struct mddev *mddev,
6434 				 const char *name)
6435 {
6436 	struct md_thread *thread;
6437 
6438 	thread = kzalloc(sizeof(struct md_thread), GFP_KERNEL);
6439 	if (!thread)
6440 		return NULL;
6441 
6442 	init_waitqueue_head(&thread->wqueue);
6443 
6444 	thread->run = run;
6445 	thread->mddev = mddev;
6446 	thread->timeout = MAX_SCHEDULE_TIMEOUT;
6447 	thread->tsk = kthread_run(md_thread, thread,
6448 				  "%s_%s",
6449 				  mdname(thread->mddev),
6450 				  name ?: mddev->pers->name);
6451 	if (IS_ERR(thread->tsk)) {
6452 		kfree(thread);
6453 		return NULL;
6454 	}
6455 	return thread;
6456 }
6457 
6458 void md_unregister_thread(struct md_thread **threadp)
6459 {
6460 	struct md_thread *thread = *threadp;
6461 	if (!thread)
6462 		return;
6463 	pr_debug("interrupting MD-thread pid %d\n", task_pid_nr(thread->tsk));
6464 	/* Locking ensures that mddev_unlock does not wake_up a
6465 	 * non-existent thread
6466 	 */
6467 	spin_lock(&pers_lock);
6468 	*threadp = NULL;
6469 	spin_unlock(&pers_lock);
6470 
6471 	kthread_stop(thread->tsk);
6472 	kfree(thread);
6473 }
6474 
6475 void md_error(struct mddev *mddev, struct md_rdev *rdev)
6476 {
6477 	if (!mddev) {
6478 		MD_BUG();
6479 		return;
6480 	}
6481 
6482 	if (!rdev || test_bit(Faulty, &rdev->flags))
6483 		return;
6484 
6485 	if (!mddev->pers || !mddev->pers->error_handler)
6486 		return;
6487 	mddev->pers->error_handler(mddev,rdev);
6488 	if (mddev->degraded)
6489 		set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
6490 	sysfs_notify_dirent_safe(rdev->sysfs_state);
6491 	set_bit(MD_RECOVERY_INTR, &mddev->recovery);
6492 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
6493 	md_wakeup_thread(mddev->thread);
6494 	if (mddev->event_work.func)
6495 		queue_work(md_misc_wq, &mddev->event_work);
6496 	md_new_event_inintr(mddev);
6497 }
6498 
6499 /* seq_file implementation /proc/mdstat */
6500 
6501 static void status_unused(struct seq_file *seq)
6502 {
6503 	int i = 0;
6504 	struct md_rdev *rdev;
6505 
6506 	seq_printf(seq, "unused devices: ");
6507 
6508 	list_for_each_entry(rdev, &pending_raid_disks, same_set) {
6509 		char b[BDEVNAME_SIZE];
6510 		i++;
6511 		seq_printf(seq, "%s ",
6512 			      bdevname(rdev->bdev,b));
6513 	}
6514 	if (!i)
6515 		seq_printf(seq, "<none>");
6516 
6517 	seq_printf(seq, "\n");
6518 }
6519 
6520 
6521 static void status_resync(struct seq_file *seq, struct mddev * mddev)
6522 {
6523 	sector_t max_sectors, resync, res;
6524 	unsigned long dt, db;
6525 	sector_t rt;
6526 	int scale;
6527 	unsigned int per_milli;
6528 
6529 	resync = mddev->curr_resync - atomic_read(&mddev->recovery_active);
6530 
6531 	if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery))
6532 		max_sectors = mddev->resync_max_sectors;
6533 	else
6534 		max_sectors = mddev->dev_sectors;
6535 
6536 	/*
6537 	 * Should not happen.
6538 	 */
6539 	if (!max_sectors) {
6540 		MD_BUG();
6541 		return;
6542 	}
6543 	/* Pick 'scale' such that (resync>>scale)*1000 will fit
6544 	 * in a sector_t, and (max_sectors>>scale) will fit in a
6545 	 * u32, as those are the requirements for sector_div.
6546 	 * Thus 'scale' must be at least 10
6547 	 */
6548 	scale = 10;
6549 	if (sizeof(sector_t) > sizeof(unsigned long)) {
6550 		while ( max_sectors/2 > (1ULL<<(scale+32)))
6551 			scale++;
6552 	}
6553 	res = (resync>>scale)*1000;
6554 	sector_div(res, (u32)((max_sectors>>scale)+1));
6555 
6556 	per_milli = res;
6557 	{
6558 		int i, x = per_milli/50, y = 20-x;
6559 		seq_printf(seq, "[");
6560 		for (i = 0; i < x; i++)
6561 			seq_printf(seq, "=");
6562 		seq_printf(seq, ">");
6563 		for (i = 0; i < y; i++)
6564 			seq_printf(seq, ".");
6565 		seq_printf(seq, "] ");
6566 	}
6567 	seq_printf(seq, " %s =%3u.%u%% (%llu/%llu)",
6568 		   (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)?
6569 		    "reshape" :
6570 		    (test_bit(MD_RECOVERY_CHECK, &mddev->recovery)?
6571 		     "check" :
6572 		     (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) ?
6573 		      "resync" : "recovery"))),
6574 		   per_milli/10, per_milli % 10,
6575 		   (unsigned long long) resync/2,
6576 		   (unsigned long long) max_sectors/2);
6577 
6578 	/*
6579 	 * dt: time from mark until now
6580 	 * db: blocks written from mark until now
6581 	 * rt: remaining time
6582 	 *
6583 	 * rt is a sector_t, so could be 32bit or 64bit.
6584 	 * So we divide before multiply in case it is 32bit and close
6585 	 * to the limit.
6586 	 * We scale the divisor (db) by 32 to avoid losing precision
6587 	 * near the end of resync when the number of remaining sectors
6588 	 * is close to 'db'.
6589 	 * We then divide rt by 32 after multiplying by db to compensate.
6590 	 * The '+1' avoids division by zero if db is very small.
6591 	 */
6592 	dt = ((jiffies - mddev->resync_mark) / HZ);
6593 	if (!dt) dt++;
6594 	db = (mddev->curr_mark_cnt - atomic_read(&mddev->recovery_active))
6595 		- mddev->resync_mark_cnt;
6596 
6597 	rt = max_sectors - resync;    /* number of remaining sectors */
6598 	sector_div(rt, db/32+1);
6599 	rt *= dt;
6600 	rt >>= 5;
6601 
6602 	seq_printf(seq, " finish=%lu.%lumin", (unsigned long)rt / 60,
6603 		   ((unsigned long)rt % 60)/6);
6604 
6605 	seq_printf(seq, " speed=%ldK/sec", db/2/dt);
6606 }
6607 
6608 static void *md_seq_start(struct seq_file *seq, loff_t *pos)
6609 {
6610 	struct list_head *tmp;
6611 	loff_t l = *pos;
6612 	struct mddev *mddev;
6613 
6614 	if (l >= 0x10000)
6615 		return NULL;
6616 	if (!l--)
6617 		/* header */
6618 		return (void*)1;
6619 
6620 	spin_lock(&all_mddevs_lock);
6621 	list_for_each(tmp,&all_mddevs)
6622 		if (!l--) {
6623 			mddev = list_entry(tmp, struct mddev, all_mddevs);
6624 			mddev_get(mddev);
6625 			spin_unlock(&all_mddevs_lock);
6626 			return mddev;
6627 		}
6628 	spin_unlock(&all_mddevs_lock);
6629 	if (!l--)
6630 		return (void*)2;/* tail */
6631 	return NULL;
6632 }
6633 
6634 static void *md_seq_next(struct seq_file *seq, void *v, loff_t *pos)
6635 {
6636 	struct list_head *tmp;
6637 	struct mddev *next_mddev, *mddev = v;
6638 
6639 	++*pos;
6640 	if (v == (void*)2)
6641 		return NULL;
6642 
6643 	spin_lock(&all_mddevs_lock);
6644 	if (v == (void*)1)
6645 		tmp = all_mddevs.next;
6646 	else
6647 		tmp = mddev->all_mddevs.next;
6648 	if (tmp != &all_mddevs)
6649 		next_mddev = mddev_get(list_entry(tmp,struct mddev,all_mddevs));
6650 	else {
6651 		next_mddev = (void*)2;
6652 		*pos = 0x10000;
6653 	}
6654 	spin_unlock(&all_mddevs_lock);
6655 
6656 	if (v != (void*)1)
6657 		mddev_put(mddev);
6658 	return next_mddev;
6659 
6660 }
6661 
6662 static void md_seq_stop(struct seq_file *seq, void *v)
6663 {
6664 	struct mddev *mddev = v;
6665 
6666 	if (mddev && v != (void*)1 && v != (void*)2)
6667 		mddev_put(mddev);
6668 }
6669 
6670 static int md_seq_show(struct seq_file *seq, void *v)
6671 {
6672 	struct mddev *mddev = v;
6673 	sector_t sectors;
6674 	struct md_rdev *rdev;
6675 	struct bitmap *bitmap;
6676 
6677 	if (v == (void*)1) {
6678 		struct md_personality *pers;
6679 		seq_printf(seq, "Personalities : ");
6680 		spin_lock(&pers_lock);
6681 		list_for_each_entry(pers, &pers_list, list)
6682 			seq_printf(seq, "[%s] ", pers->name);
6683 
6684 		spin_unlock(&pers_lock);
6685 		seq_printf(seq, "\n");
6686 		seq->poll_event = atomic_read(&md_event_count);
6687 		return 0;
6688 	}
6689 	if (v == (void*)2) {
6690 		status_unused(seq);
6691 		return 0;
6692 	}
6693 
6694 	if (mddev_lock(mddev) < 0)
6695 		return -EINTR;
6696 
6697 	if (mddev->pers || mddev->raid_disks || !list_empty(&mddev->disks)) {
6698 		seq_printf(seq, "%s : %sactive", mdname(mddev),
6699 						mddev->pers ? "" : "in");
6700 		if (mddev->pers) {
6701 			if (mddev->ro==1)
6702 				seq_printf(seq, " (read-only)");
6703 			if (mddev->ro==2)
6704 				seq_printf(seq, " (auto-read-only)");
6705 			seq_printf(seq, " %s", mddev->pers->name);
6706 		}
6707 
6708 		sectors = 0;
6709 		list_for_each_entry(rdev, &mddev->disks, same_set) {
6710 			char b[BDEVNAME_SIZE];
6711 			seq_printf(seq, " %s[%d]",
6712 				bdevname(rdev->bdev,b), rdev->desc_nr);
6713 			if (test_bit(WriteMostly, &rdev->flags))
6714 				seq_printf(seq, "(W)");
6715 			if (test_bit(Faulty, &rdev->flags)) {
6716 				seq_printf(seq, "(F)");
6717 				continue;
6718 			} else if (rdev->raid_disk < 0)
6719 				seq_printf(seq, "(S)"); /* spare */
6720 			sectors += rdev->sectors;
6721 		}
6722 
6723 		if (!list_empty(&mddev->disks)) {
6724 			if (mddev->pers)
6725 				seq_printf(seq, "\n      %llu blocks",
6726 					   (unsigned long long)
6727 					   mddev->array_sectors / 2);
6728 			else
6729 				seq_printf(seq, "\n      %llu blocks",
6730 					   (unsigned long long)sectors / 2);
6731 		}
6732 		if (mddev->persistent) {
6733 			if (mddev->major_version != 0 ||
6734 			    mddev->minor_version != 90) {
6735 				seq_printf(seq," super %d.%d",
6736 					   mddev->major_version,
6737 					   mddev->minor_version);
6738 			}
6739 		} else if (mddev->external)
6740 			seq_printf(seq, " super external:%s",
6741 				   mddev->metadata_type);
6742 		else
6743 			seq_printf(seq, " super non-persistent");
6744 
6745 		if (mddev->pers) {
6746 			mddev->pers->status(seq, mddev);
6747 	 		seq_printf(seq, "\n      ");
6748 			if (mddev->pers->sync_request) {
6749 				if (mddev->curr_resync > 2) {
6750 					status_resync(seq, mddev);
6751 					seq_printf(seq, "\n      ");
6752 				} else if (mddev->curr_resync == 1 || mddev->curr_resync == 2)
6753 					seq_printf(seq, "\tresync=DELAYED\n      ");
6754 				else if (mddev->recovery_cp < MaxSector)
6755 					seq_printf(seq, "\tresync=PENDING\n      ");
6756 			}
6757 		} else
6758 			seq_printf(seq, "\n       ");
6759 
6760 		if ((bitmap = mddev->bitmap)) {
6761 			unsigned long chunk_kb;
6762 			unsigned long flags;
6763 			spin_lock_irqsave(&bitmap->lock, flags);
6764 			chunk_kb = mddev->bitmap_info.chunksize >> 10;
6765 			seq_printf(seq, "bitmap: %lu/%lu pages [%luKB], "
6766 				"%lu%s chunk",
6767 				bitmap->pages - bitmap->missing_pages,
6768 				bitmap->pages,
6769 				(bitmap->pages - bitmap->missing_pages)
6770 					<< (PAGE_SHIFT - 10),
6771 				chunk_kb ? chunk_kb : mddev->bitmap_info.chunksize,
6772 				chunk_kb ? "KB" : "B");
6773 			if (bitmap->file) {
6774 				seq_printf(seq, ", file: ");
6775 				seq_path(seq, &bitmap->file->f_path, " \t\n");
6776 			}
6777 
6778 			seq_printf(seq, "\n");
6779 			spin_unlock_irqrestore(&bitmap->lock, flags);
6780 		}
6781 
6782 		seq_printf(seq, "\n");
6783 	}
6784 	mddev_unlock(mddev);
6785 
6786 	return 0;
6787 }
6788 
6789 static const struct seq_operations md_seq_ops = {
6790 	.start  = md_seq_start,
6791 	.next   = md_seq_next,
6792 	.stop   = md_seq_stop,
6793 	.show   = md_seq_show,
6794 };
6795 
6796 static int md_seq_open(struct inode *inode, struct file *file)
6797 {
6798 	struct seq_file *seq;
6799 	int error;
6800 
6801 	error = seq_open(file, &md_seq_ops);
6802 	if (error)
6803 		return error;
6804 
6805 	seq = file->private_data;
6806 	seq->poll_event = atomic_read(&md_event_count);
6807 	return error;
6808 }
6809 
6810 static unsigned int mdstat_poll(struct file *filp, poll_table *wait)
6811 {
6812 	struct seq_file *seq = filp->private_data;
6813 	int mask;
6814 
6815 	poll_wait(filp, &md_event_waiters, wait);
6816 
6817 	/* always allow read */
6818 	mask = POLLIN | POLLRDNORM;
6819 
6820 	if (seq->poll_event != atomic_read(&md_event_count))
6821 		mask |= POLLERR | POLLPRI;
6822 	return mask;
6823 }
6824 
6825 static const struct file_operations md_seq_fops = {
6826 	.owner		= THIS_MODULE,
6827 	.open           = md_seq_open,
6828 	.read           = seq_read,
6829 	.llseek         = seq_lseek,
6830 	.release	= seq_release_private,
6831 	.poll		= mdstat_poll,
6832 };
6833 
6834 int register_md_personality(struct md_personality *p)
6835 {
6836 	spin_lock(&pers_lock);
6837 	list_add_tail(&p->list, &pers_list);
6838 	printk(KERN_INFO "md: %s personality registered for level %d\n", p->name, p->level);
6839 	spin_unlock(&pers_lock);
6840 	return 0;
6841 }
6842 
6843 int unregister_md_personality(struct md_personality *p)
6844 {
6845 	printk(KERN_INFO "md: %s personality unregistered\n", p->name);
6846 	spin_lock(&pers_lock);
6847 	list_del_init(&p->list);
6848 	spin_unlock(&pers_lock);
6849 	return 0;
6850 }
6851 
6852 static int is_mddev_idle(struct mddev *mddev, int init)
6853 {
6854 	struct md_rdev * rdev;
6855 	int idle;
6856 	int curr_events;
6857 
6858 	idle = 1;
6859 	rcu_read_lock();
6860 	rdev_for_each_rcu(rdev, mddev) {
6861 		struct gendisk *disk = rdev->bdev->bd_contains->bd_disk;
6862 		curr_events = (int)part_stat_read(&disk->part0, sectors[0]) +
6863 			      (int)part_stat_read(&disk->part0, sectors[1]) -
6864 			      atomic_read(&disk->sync_io);
6865 		/* sync IO will cause sync_io to increase before the disk_stats
6866 		 * as sync_io is counted when a request starts, and
6867 		 * disk_stats is counted when it completes.
6868 		 * So resync activity will cause curr_events to be smaller than
6869 		 * when there was no such activity.
6870 		 * non-sync IO will cause disk_stat to increase without
6871 		 * increasing sync_io so curr_events will (eventually)
6872 		 * be larger than it was before.  Once it becomes
6873 		 * substantially larger, the test below will cause
6874 		 * the array to appear non-idle, and resync will slow
6875 		 * down.
6876 		 * If there is a lot of outstanding resync activity when
6877 		 * we set last_event to curr_events, then all that activity
6878 		 * completing might cause the array to appear non-idle
6879 		 * and resync will be slowed down even though there might
6880 		 * not have been non-resync activity.  This will only
6881 		 * happen once though.  'last_events' will soon reflect
6882 		 * the state where there is little or no outstanding
6883 		 * resync requests, and further resync activity will
6884 		 * always make curr_events less than last_events.
6885 		 *
6886 		 */
6887 		if (init || curr_events - rdev->last_events > 64) {
6888 			rdev->last_events = curr_events;
6889 			idle = 0;
6890 		}
6891 	}
6892 	rcu_read_unlock();
6893 	return idle;
6894 }
6895 
6896 void md_done_sync(struct mddev *mddev, int blocks, int ok)
6897 {
6898 	/* another "blocks" (512byte) blocks have been synced */
6899 	atomic_sub(blocks, &mddev->recovery_active);
6900 	wake_up(&mddev->recovery_wait);
6901 	if (!ok) {
6902 		set_bit(MD_RECOVERY_INTR, &mddev->recovery);
6903 		md_wakeup_thread(mddev->thread);
6904 		// stop recovery, signal do_sync ....
6905 	}
6906 }
6907 
6908 
6909 /* md_write_start(mddev, bi)
6910  * If we need to update some array metadata (e.g. 'active' flag
6911  * in superblock) before writing, schedule a superblock update
6912  * and wait for it to complete.
6913  */
6914 void md_write_start(struct mddev *mddev, struct bio *bi)
6915 {
6916 	int did_change = 0;
6917 	if (bio_data_dir(bi) != WRITE)
6918 		return;
6919 
6920 	BUG_ON(mddev->ro == 1);
6921 	if (mddev->ro == 2) {
6922 		/* need to switch to read/write */
6923 		mddev->ro = 0;
6924 		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
6925 		md_wakeup_thread(mddev->thread);
6926 		md_wakeup_thread(mddev->sync_thread);
6927 		did_change = 1;
6928 	}
6929 	atomic_inc(&mddev->writes_pending);
6930 	if (mddev->safemode == 1)
6931 		mddev->safemode = 0;
6932 	if (mddev->in_sync) {
6933 		spin_lock_irq(&mddev->write_lock);
6934 		if (mddev->in_sync) {
6935 			mddev->in_sync = 0;
6936 			set_bit(MD_CHANGE_CLEAN, &mddev->flags);
6937 			set_bit(MD_CHANGE_PENDING, &mddev->flags);
6938 			md_wakeup_thread(mddev->thread);
6939 			did_change = 1;
6940 		}
6941 		spin_unlock_irq(&mddev->write_lock);
6942 	}
6943 	if (did_change)
6944 		sysfs_notify_dirent_safe(mddev->sysfs_state);
6945 	wait_event(mddev->sb_wait,
6946 		   !test_bit(MD_CHANGE_PENDING, &mddev->flags));
6947 }
6948 
6949 void md_write_end(struct mddev *mddev)
6950 {
6951 	if (atomic_dec_and_test(&mddev->writes_pending)) {
6952 		if (mddev->safemode == 2)
6953 			md_wakeup_thread(mddev->thread);
6954 		else if (mddev->safemode_delay)
6955 			mod_timer(&mddev->safemode_timer, jiffies + mddev->safemode_delay);
6956 	}
6957 }
6958 
6959 /* md_allow_write(mddev)
6960  * Calling this ensures that the array is marked 'active' so that writes
6961  * may proceed without blocking.  It is important to call this before
6962  * attempting a GFP_KERNEL allocation while holding the mddev lock.
6963  * Must be called with mddev_lock held.
6964  *
6965  * In the ->external case MD_CHANGE_CLEAN can not be cleared until mddev->lock
6966  * is dropped, so return -EAGAIN after notifying userspace.
6967  */
6968 int md_allow_write(struct mddev *mddev)
6969 {
6970 	if (!mddev->pers)
6971 		return 0;
6972 	if (mddev->ro)
6973 		return 0;
6974 	if (!mddev->pers->sync_request)
6975 		return 0;
6976 
6977 	spin_lock_irq(&mddev->write_lock);
6978 	if (mddev->in_sync) {
6979 		mddev->in_sync = 0;
6980 		set_bit(MD_CHANGE_CLEAN, &mddev->flags);
6981 		set_bit(MD_CHANGE_PENDING, &mddev->flags);
6982 		if (mddev->safemode_delay &&
6983 		    mddev->safemode == 0)
6984 			mddev->safemode = 1;
6985 		spin_unlock_irq(&mddev->write_lock);
6986 		md_update_sb(mddev, 0);
6987 		sysfs_notify_dirent_safe(mddev->sysfs_state);
6988 	} else
6989 		spin_unlock_irq(&mddev->write_lock);
6990 
6991 	if (test_bit(MD_CHANGE_PENDING, &mddev->flags))
6992 		return -EAGAIN;
6993 	else
6994 		return 0;
6995 }
6996 EXPORT_SYMBOL_GPL(md_allow_write);
6997 
6998 #define SYNC_MARKS	10
6999 #define	SYNC_MARK_STEP	(3*HZ)
7000 void md_do_sync(struct mddev *mddev)
7001 {
7002 	struct mddev *mddev2;
7003 	unsigned int currspeed = 0,
7004 		 window;
7005 	sector_t max_sectors,j, io_sectors;
7006 	unsigned long mark[SYNC_MARKS];
7007 	sector_t mark_cnt[SYNC_MARKS];
7008 	int last_mark,m;
7009 	struct list_head *tmp;
7010 	sector_t last_check;
7011 	int skipped = 0;
7012 	struct md_rdev *rdev;
7013 	char *desc;
7014 
7015 	/* just incase thread restarts... */
7016 	if (test_bit(MD_RECOVERY_DONE, &mddev->recovery))
7017 		return;
7018 	if (mddev->ro) /* never try to sync a read-only array */
7019 		return;
7020 
7021 	if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
7022 		if (test_bit(MD_RECOVERY_CHECK, &mddev->recovery))
7023 			desc = "data-check";
7024 		else if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
7025 			desc = "requested-resync";
7026 		else
7027 			desc = "resync";
7028 	} else if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
7029 		desc = "reshape";
7030 	else
7031 		desc = "recovery";
7032 
7033 	/* we overload curr_resync somewhat here.
7034 	 * 0 == not engaged in resync at all
7035 	 * 2 == checking that there is no conflict with another sync
7036 	 * 1 == like 2, but have yielded to allow conflicting resync to
7037 	 *		commense
7038 	 * other == active in resync - this many blocks
7039 	 *
7040 	 * Before starting a resync we must have set curr_resync to
7041 	 * 2, and then checked that every "conflicting" array has curr_resync
7042 	 * less than ours.  When we find one that is the same or higher
7043 	 * we wait on resync_wait.  To avoid deadlock, we reduce curr_resync
7044 	 * to 1 if we choose to yield (based arbitrarily on address of mddev structure).
7045 	 * This will mean we have to start checking from the beginning again.
7046 	 *
7047 	 */
7048 
7049 	do {
7050 		mddev->curr_resync = 2;
7051 
7052 	try_again:
7053 		if (kthread_should_stop())
7054 			set_bit(MD_RECOVERY_INTR, &mddev->recovery);
7055 
7056 		if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
7057 			goto skip;
7058 		for_each_mddev(mddev2, tmp) {
7059 			if (mddev2 == mddev)
7060 				continue;
7061 			if (!mddev->parallel_resync
7062 			&&  mddev2->curr_resync
7063 			&&  match_mddev_units(mddev, mddev2)) {
7064 				DEFINE_WAIT(wq);
7065 				if (mddev < mddev2 && mddev->curr_resync == 2) {
7066 					/* arbitrarily yield */
7067 					mddev->curr_resync = 1;
7068 					wake_up(&resync_wait);
7069 				}
7070 				if (mddev > mddev2 && mddev->curr_resync == 1)
7071 					/* no need to wait here, we can wait the next
7072 					 * time 'round when curr_resync == 2
7073 					 */
7074 					continue;
7075 				/* We need to wait 'interruptible' so as not to
7076 				 * contribute to the load average, and not to
7077 				 * be caught by 'softlockup'
7078 				 */
7079 				prepare_to_wait(&resync_wait, &wq, TASK_INTERRUPTIBLE);
7080 				if (!kthread_should_stop() &&
7081 				    mddev2->curr_resync >= mddev->curr_resync) {
7082 					printk(KERN_INFO "md: delaying %s of %s"
7083 					       " until %s has finished (they"
7084 					       " share one or more physical units)\n",
7085 					       desc, mdname(mddev), mdname(mddev2));
7086 					mddev_put(mddev2);
7087 					if (signal_pending(current))
7088 						flush_signals(current);
7089 					schedule();
7090 					finish_wait(&resync_wait, &wq);
7091 					goto try_again;
7092 				}
7093 				finish_wait(&resync_wait, &wq);
7094 			}
7095 		}
7096 	} while (mddev->curr_resync < 2);
7097 
7098 	j = 0;
7099 	if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
7100 		/* resync follows the size requested by the personality,
7101 		 * which defaults to physical size, but can be virtual size
7102 		 */
7103 		max_sectors = mddev->resync_max_sectors;
7104 		mddev->resync_mismatches = 0;
7105 		/* we don't use the checkpoint if there's a bitmap */
7106 		if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
7107 			j = mddev->resync_min;
7108 		else if (!mddev->bitmap)
7109 			j = mddev->recovery_cp;
7110 
7111 	} else if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
7112 		max_sectors = mddev->dev_sectors;
7113 	else {
7114 		/* recovery follows the physical size of devices */
7115 		max_sectors = mddev->dev_sectors;
7116 		j = MaxSector;
7117 		rcu_read_lock();
7118 		list_for_each_entry_rcu(rdev, &mddev->disks, same_set)
7119 			if (rdev->raid_disk >= 0 &&
7120 			    !test_bit(Faulty, &rdev->flags) &&
7121 			    !test_bit(In_sync, &rdev->flags) &&
7122 			    rdev->recovery_offset < j)
7123 				j = rdev->recovery_offset;
7124 		rcu_read_unlock();
7125 	}
7126 
7127 	printk(KERN_INFO "md: %s of RAID array %s\n", desc, mdname(mddev));
7128 	printk(KERN_INFO "md: minimum _guaranteed_  speed:"
7129 		" %d KB/sec/disk.\n", speed_min(mddev));
7130 	printk(KERN_INFO "md: using maximum available idle IO bandwidth "
7131 	       "(but not more than %d KB/sec) for %s.\n",
7132 	       speed_max(mddev), desc);
7133 
7134 	is_mddev_idle(mddev, 1); /* this initializes IO event counters */
7135 
7136 	io_sectors = 0;
7137 	for (m = 0; m < SYNC_MARKS; m++) {
7138 		mark[m] = jiffies;
7139 		mark_cnt[m] = io_sectors;
7140 	}
7141 	last_mark = 0;
7142 	mddev->resync_mark = mark[last_mark];
7143 	mddev->resync_mark_cnt = mark_cnt[last_mark];
7144 
7145 	/*
7146 	 * Tune reconstruction:
7147 	 */
7148 	window = 32*(PAGE_SIZE/512);
7149 	printk(KERN_INFO "md: using %dk window, over a total of %lluk.\n",
7150 		window/2, (unsigned long long)max_sectors/2);
7151 
7152 	atomic_set(&mddev->recovery_active, 0);
7153 	last_check = 0;
7154 
7155 	if (j>2) {
7156 		printk(KERN_INFO
7157 		       "md: resuming %s of %s from checkpoint.\n",
7158 		       desc, mdname(mddev));
7159 		mddev->curr_resync = j;
7160 	}
7161 	mddev->curr_resync_completed = j;
7162 
7163 	while (j < max_sectors) {
7164 		sector_t sectors;
7165 
7166 		skipped = 0;
7167 
7168 		if (!test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
7169 		    ((mddev->curr_resync > mddev->curr_resync_completed &&
7170 		      (mddev->curr_resync - mddev->curr_resync_completed)
7171 		      > (max_sectors >> 4)) ||
7172 		     (j - mddev->curr_resync_completed)*2
7173 		     >= mddev->resync_max - mddev->curr_resync_completed
7174 			    )) {
7175 			/* time to update curr_resync_completed */
7176 			wait_event(mddev->recovery_wait,
7177 				   atomic_read(&mddev->recovery_active) == 0);
7178 			mddev->curr_resync_completed = j;
7179 			set_bit(MD_CHANGE_CLEAN, &mddev->flags);
7180 			sysfs_notify(&mddev->kobj, NULL, "sync_completed");
7181 		}
7182 
7183 		while (j >= mddev->resync_max && !kthread_should_stop()) {
7184 			/* As this condition is controlled by user-space,
7185 			 * we can block indefinitely, so use '_interruptible'
7186 			 * to avoid triggering warnings.
7187 			 */
7188 			flush_signals(current); /* just in case */
7189 			wait_event_interruptible(mddev->recovery_wait,
7190 						 mddev->resync_max > j
7191 						 || kthread_should_stop());
7192 		}
7193 
7194 		if (kthread_should_stop())
7195 			goto interrupted;
7196 
7197 		sectors = mddev->pers->sync_request(mddev, j, &skipped,
7198 						  currspeed < speed_min(mddev));
7199 		if (sectors == 0) {
7200 			set_bit(MD_RECOVERY_INTR, &mddev->recovery);
7201 			goto out;
7202 		}
7203 
7204 		if (!skipped) { /* actual IO requested */
7205 			io_sectors += sectors;
7206 			atomic_add(sectors, &mddev->recovery_active);
7207 		}
7208 
7209 		if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
7210 			break;
7211 
7212 		j += sectors;
7213 		if (j>1) mddev->curr_resync = j;
7214 		mddev->curr_mark_cnt = io_sectors;
7215 		if (last_check == 0)
7216 			/* this is the earliest that rebuild will be
7217 			 * visible in /proc/mdstat
7218 			 */
7219 			md_new_event(mddev);
7220 
7221 		if (last_check + window > io_sectors || j == max_sectors)
7222 			continue;
7223 
7224 		last_check = io_sectors;
7225 	repeat:
7226 		if (time_after_eq(jiffies, mark[last_mark] + SYNC_MARK_STEP )) {
7227 			/* step marks */
7228 			int next = (last_mark+1) % SYNC_MARKS;
7229 
7230 			mddev->resync_mark = mark[next];
7231 			mddev->resync_mark_cnt = mark_cnt[next];
7232 			mark[next] = jiffies;
7233 			mark_cnt[next] = io_sectors - atomic_read(&mddev->recovery_active);
7234 			last_mark = next;
7235 		}
7236 
7237 
7238 		if (kthread_should_stop())
7239 			goto interrupted;
7240 
7241 
7242 		/*
7243 		 * this loop exits only if either when we are slower than
7244 		 * the 'hard' speed limit, or the system was IO-idle for
7245 		 * a jiffy.
7246 		 * the system might be non-idle CPU-wise, but we only care
7247 		 * about not overloading the IO subsystem. (things like an
7248 		 * e2fsck being done on the RAID array should execute fast)
7249 		 */
7250 		cond_resched();
7251 
7252 		currspeed = ((unsigned long)(io_sectors-mddev->resync_mark_cnt))/2
7253 			/((jiffies-mddev->resync_mark)/HZ +1) +1;
7254 
7255 		if (currspeed > speed_min(mddev)) {
7256 			if ((currspeed > speed_max(mddev)) ||
7257 					!is_mddev_idle(mddev, 0)) {
7258 				msleep(500);
7259 				goto repeat;
7260 			}
7261 		}
7262 	}
7263 	printk(KERN_INFO "md: %s: %s done.\n",mdname(mddev), desc);
7264 	/*
7265 	 * this also signals 'finished resyncing' to md_stop
7266 	 */
7267  out:
7268 	wait_event(mddev->recovery_wait, !atomic_read(&mddev->recovery_active));
7269 
7270 	/* tell personality that we are finished */
7271 	mddev->pers->sync_request(mddev, max_sectors, &skipped, 1);
7272 
7273 	if (!test_bit(MD_RECOVERY_CHECK, &mddev->recovery) &&
7274 	    mddev->curr_resync > 2) {
7275 		if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
7276 			if (test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
7277 				if (mddev->curr_resync >= mddev->recovery_cp) {
7278 					printk(KERN_INFO
7279 					       "md: checkpointing %s of %s.\n",
7280 					       desc, mdname(mddev));
7281 					mddev->recovery_cp = mddev->curr_resync;
7282 				}
7283 			} else
7284 				mddev->recovery_cp = MaxSector;
7285 		} else {
7286 			if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery))
7287 				mddev->curr_resync = MaxSector;
7288 			rcu_read_lock();
7289 			list_for_each_entry_rcu(rdev, &mddev->disks, same_set)
7290 				if (rdev->raid_disk >= 0 &&
7291 				    mddev->delta_disks >= 0 &&
7292 				    !test_bit(Faulty, &rdev->flags) &&
7293 				    !test_bit(In_sync, &rdev->flags) &&
7294 				    rdev->recovery_offset < mddev->curr_resync)
7295 					rdev->recovery_offset = mddev->curr_resync;
7296 			rcu_read_unlock();
7297 		}
7298 	}
7299 	set_bit(MD_CHANGE_DEVS, &mddev->flags);
7300 
7301  skip:
7302 	if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
7303 		/* We completed so min/max setting can be forgotten if used. */
7304 		if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
7305 			mddev->resync_min = 0;
7306 		mddev->resync_max = MaxSector;
7307 	} else if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
7308 		mddev->resync_min = mddev->curr_resync_completed;
7309 	mddev->curr_resync = 0;
7310 	wake_up(&resync_wait);
7311 	set_bit(MD_RECOVERY_DONE, &mddev->recovery);
7312 	md_wakeup_thread(mddev->thread);
7313 	return;
7314 
7315  interrupted:
7316 	/*
7317 	 * got a signal, exit.
7318 	 */
7319 	printk(KERN_INFO
7320 	       "md: md_do_sync() got signal ... exiting\n");
7321 	set_bit(MD_RECOVERY_INTR, &mddev->recovery);
7322 	goto out;
7323 
7324 }
7325 EXPORT_SYMBOL_GPL(md_do_sync);
7326 
7327 static int remove_and_add_spares(struct mddev *mddev)
7328 {
7329 	struct md_rdev *rdev;
7330 	int spares = 0;
7331 
7332 	mddev->curr_resync_completed = 0;
7333 
7334 	list_for_each_entry(rdev, &mddev->disks, same_set)
7335 		if (rdev->raid_disk >= 0 &&
7336 		    !test_bit(Blocked, &rdev->flags) &&
7337 		    (test_bit(Faulty, &rdev->flags) ||
7338 		     ! test_bit(In_sync, &rdev->flags)) &&
7339 		    atomic_read(&rdev->nr_pending)==0) {
7340 			if (mddev->pers->hot_remove_disk(
7341 				    mddev, rdev->raid_disk)==0) {
7342 				sysfs_unlink_rdev(mddev, rdev);
7343 				rdev->raid_disk = -1;
7344 			}
7345 		}
7346 
7347 	if (mddev->degraded) {
7348 		list_for_each_entry(rdev, &mddev->disks, same_set) {
7349 			if (rdev->raid_disk >= 0 &&
7350 			    !test_bit(In_sync, &rdev->flags) &&
7351 			    !test_bit(Faulty, &rdev->flags))
7352 				spares++;
7353 			if (rdev->raid_disk < 0
7354 			    && !test_bit(Faulty, &rdev->flags)) {
7355 				rdev->recovery_offset = 0;
7356 				if (mddev->pers->
7357 				    hot_add_disk(mddev, rdev) == 0) {
7358 					if (sysfs_link_rdev(mddev, rdev))
7359 						/* failure here is OK */;
7360 					spares++;
7361 					md_new_event(mddev);
7362 					set_bit(MD_CHANGE_DEVS, &mddev->flags);
7363 				}
7364 			}
7365 		}
7366 	}
7367 	return spares;
7368 }
7369 
7370 static void reap_sync_thread(struct mddev *mddev)
7371 {
7372 	struct md_rdev *rdev;
7373 
7374 	/* resync has finished, collect result */
7375 	md_unregister_thread(&mddev->sync_thread);
7376 	if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery) &&
7377 	    !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
7378 		/* success...*/
7379 		/* activate any spares */
7380 		if (mddev->pers->spare_active(mddev))
7381 			sysfs_notify(&mddev->kobj, NULL,
7382 				     "degraded");
7383 	}
7384 	if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
7385 	    mddev->pers->finish_reshape)
7386 		mddev->pers->finish_reshape(mddev);
7387 
7388 	/* If array is no-longer degraded, then any saved_raid_disk
7389 	 * information must be scrapped.  Also if any device is now
7390 	 * In_sync we must scrape the saved_raid_disk for that device
7391 	 * do the superblock for an incrementally recovered device
7392 	 * written out.
7393 	 */
7394 	list_for_each_entry(rdev, &mddev->disks, same_set)
7395 		if (!mddev->degraded ||
7396 		    test_bit(In_sync, &rdev->flags))
7397 			rdev->saved_raid_disk = -1;
7398 
7399 	md_update_sb(mddev, 1);
7400 	clear_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
7401 	clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
7402 	clear_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
7403 	clear_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
7404 	clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
7405 	/* flag recovery needed just to double check */
7406 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
7407 	sysfs_notify_dirent_safe(mddev->sysfs_action);
7408 	md_new_event(mddev);
7409 	if (mddev->event_work.func)
7410 		queue_work(md_misc_wq, &mddev->event_work);
7411 }
7412 
7413 /*
7414  * This routine is regularly called by all per-raid-array threads to
7415  * deal with generic issues like resync and super-block update.
7416  * Raid personalities that don't have a thread (linear/raid0) do not
7417  * need this as they never do any recovery or update the superblock.
7418  *
7419  * It does not do any resync itself, but rather "forks" off other threads
7420  * to do that as needed.
7421  * When it is determined that resync is needed, we set MD_RECOVERY_RUNNING in
7422  * "->recovery" and create a thread at ->sync_thread.
7423  * When the thread finishes it sets MD_RECOVERY_DONE
7424  * and wakeups up this thread which will reap the thread and finish up.
7425  * This thread also removes any faulty devices (with nr_pending == 0).
7426  *
7427  * The overall approach is:
7428  *  1/ if the superblock needs updating, update it.
7429  *  2/ If a recovery thread is running, don't do anything else.
7430  *  3/ If recovery has finished, clean up, possibly marking spares active.
7431  *  4/ If there are any faulty devices, remove them.
7432  *  5/ If array is degraded, try to add spares devices
7433  *  6/ If array has spares or is not in-sync, start a resync thread.
7434  */
7435 void md_check_recovery(struct mddev *mddev)
7436 {
7437 	if (mddev->suspended)
7438 		return;
7439 
7440 	if (mddev->bitmap)
7441 		bitmap_daemon_work(mddev);
7442 
7443 	if (signal_pending(current)) {
7444 		if (mddev->pers->sync_request && !mddev->external) {
7445 			printk(KERN_INFO "md: %s in immediate safe mode\n",
7446 			       mdname(mddev));
7447 			mddev->safemode = 2;
7448 		}
7449 		flush_signals(current);
7450 	}
7451 
7452 	if (mddev->ro && !test_bit(MD_RECOVERY_NEEDED, &mddev->recovery))
7453 		return;
7454 	if ( ! (
7455 		(mddev->flags & ~ (1<<MD_CHANGE_PENDING)) ||
7456 		test_bit(MD_RECOVERY_NEEDED, &mddev->recovery) ||
7457 		test_bit(MD_RECOVERY_DONE, &mddev->recovery) ||
7458 		(mddev->external == 0 && mddev->safemode == 1) ||
7459 		(mddev->safemode == 2 && ! atomic_read(&mddev->writes_pending)
7460 		 && !mddev->in_sync && mddev->recovery_cp == MaxSector)
7461 		))
7462 		return;
7463 
7464 	if (mddev_trylock(mddev)) {
7465 		int spares = 0;
7466 
7467 		if (mddev->ro) {
7468 			/* Only thing we do on a ro array is remove
7469 			 * failed devices.
7470 			 */
7471 			struct md_rdev *rdev;
7472 			list_for_each_entry(rdev, &mddev->disks, same_set)
7473 				if (rdev->raid_disk >= 0 &&
7474 				    !test_bit(Blocked, &rdev->flags) &&
7475 				    test_bit(Faulty, &rdev->flags) &&
7476 				    atomic_read(&rdev->nr_pending)==0) {
7477 					if (mddev->pers->hot_remove_disk(
7478 						    mddev, rdev->raid_disk)==0) {
7479 						sysfs_unlink_rdev(mddev, rdev);
7480 						rdev->raid_disk = -1;
7481 					}
7482 				}
7483 			clear_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
7484 			goto unlock;
7485 		}
7486 
7487 		if (!mddev->external) {
7488 			int did_change = 0;
7489 			spin_lock_irq(&mddev->write_lock);
7490 			if (mddev->safemode &&
7491 			    !atomic_read(&mddev->writes_pending) &&
7492 			    !mddev->in_sync &&
7493 			    mddev->recovery_cp == MaxSector) {
7494 				mddev->in_sync = 1;
7495 				did_change = 1;
7496 				set_bit(MD_CHANGE_CLEAN, &mddev->flags);
7497 			}
7498 			if (mddev->safemode == 1)
7499 				mddev->safemode = 0;
7500 			spin_unlock_irq(&mddev->write_lock);
7501 			if (did_change)
7502 				sysfs_notify_dirent_safe(mddev->sysfs_state);
7503 		}
7504 
7505 		if (mddev->flags)
7506 			md_update_sb(mddev, 0);
7507 
7508 		if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) &&
7509 		    !test_bit(MD_RECOVERY_DONE, &mddev->recovery)) {
7510 			/* resync/recovery still happening */
7511 			clear_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
7512 			goto unlock;
7513 		}
7514 		if (mddev->sync_thread) {
7515 			reap_sync_thread(mddev);
7516 			goto unlock;
7517 		}
7518 		/* Set RUNNING before clearing NEEDED to avoid
7519 		 * any transients in the value of "sync_action".
7520 		 */
7521 		set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
7522 		clear_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
7523 		/* Clear some bits that don't mean anything, but
7524 		 * might be left set
7525 		 */
7526 		clear_bit(MD_RECOVERY_INTR, &mddev->recovery);
7527 		clear_bit(MD_RECOVERY_DONE, &mddev->recovery);
7528 
7529 		if (test_bit(MD_RECOVERY_FROZEN, &mddev->recovery))
7530 			goto unlock;
7531 		/* no recovery is running.
7532 		 * remove any failed drives, then
7533 		 * add spares if possible.
7534 		 * Spare are also removed and re-added, to allow
7535 		 * the personality to fail the re-add.
7536 		 */
7537 
7538 		if (mddev->reshape_position != MaxSector) {
7539 			if (mddev->pers->check_reshape == NULL ||
7540 			    mddev->pers->check_reshape(mddev) != 0)
7541 				/* Cannot proceed */
7542 				goto unlock;
7543 			set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
7544 			clear_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
7545 		} else if ((spares = remove_and_add_spares(mddev))) {
7546 			clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
7547 			clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
7548 			clear_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
7549 			set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
7550 		} else if (mddev->recovery_cp < MaxSector) {
7551 			set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
7552 			clear_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
7553 		} else if (!test_bit(MD_RECOVERY_SYNC, &mddev->recovery))
7554 			/* nothing to be done ... */
7555 			goto unlock;
7556 
7557 		if (mddev->pers->sync_request) {
7558 			if (spares && mddev->bitmap && ! mddev->bitmap->file) {
7559 				/* We are adding a device or devices to an array
7560 				 * which has the bitmap stored on all devices.
7561 				 * So make sure all bitmap pages get written
7562 				 */
7563 				bitmap_write_all(mddev->bitmap);
7564 			}
7565 			mddev->sync_thread = md_register_thread(md_do_sync,
7566 								mddev,
7567 								"resync");
7568 			if (!mddev->sync_thread) {
7569 				printk(KERN_ERR "%s: could not start resync"
7570 					" thread...\n",
7571 					mdname(mddev));
7572 				/* leave the spares where they are, it shouldn't hurt */
7573 				clear_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
7574 				clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
7575 				clear_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
7576 				clear_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
7577 				clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
7578 			} else
7579 				md_wakeup_thread(mddev->sync_thread);
7580 			sysfs_notify_dirent_safe(mddev->sysfs_action);
7581 			md_new_event(mddev);
7582 		}
7583 	unlock:
7584 		if (!mddev->sync_thread) {
7585 			clear_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
7586 			if (test_and_clear_bit(MD_RECOVERY_RECOVER,
7587 					       &mddev->recovery))
7588 				if (mddev->sysfs_action)
7589 					sysfs_notify_dirent_safe(mddev->sysfs_action);
7590 		}
7591 		mddev_unlock(mddev);
7592 	}
7593 }
7594 
7595 void md_wait_for_blocked_rdev(struct md_rdev *rdev, struct mddev *mddev)
7596 {
7597 	sysfs_notify_dirent_safe(rdev->sysfs_state);
7598 	wait_event_timeout(rdev->blocked_wait,
7599 			   !test_bit(Blocked, &rdev->flags) &&
7600 			   !test_bit(BlockedBadBlocks, &rdev->flags),
7601 			   msecs_to_jiffies(5000));
7602 	rdev_dec_pending(rdev, mddev);
7603 }
7604 EXPORT_SYMBOL(md_wait_for_blocked_rdev);
7605 
7606 
7607 /* Bad block management.
7608  * We can record which blocks on each device are 'bad' and so just
7609  * fail those blocks, or that stripe, rather than the whole device.
7610  * Entries in the bad-block table are 64bits wide.  This comprises:
7611  * Length of bad-range, in sectors: 0-511 for lengths 1-512
7612  * Start of bad-range, sector offset, 54 bits (allows 8 exbibytes)
7613  *  A 'shift' can be set so that larger blocks are tracked and
7614  *  consequently larger devices can be covered.
7615  * 'Acknowledged' flag - 1 bit. - the most significant bit.
7616  *
7617  * Locking of the bad-block table uses a seqlock so md_is_badblock
7618  * might need to retry if it is very unlucky.
7619  * We will sometimes want to check for bad blocks in a bi_end_io function,
7620  * so we use the write_seqlock_irq variant.
7621  *
7622  * When looking for a bad block we specify a range and want to
7623  * know if any block in the range is bad.  So we binary-search
7624  * to the last range that starts at-or-before the given endpoint,
7625  * (or "before the sector after the target range")
7626  * then see if it ends after the given start.
7627  * We return
7628  *  0 if there are no known bad blocks in the range
7629  *  1 if there are known bad block which are all acknowledged
7630  * -1 if there are bad blocks which have not yet been acknowledged in metadata.
7631  * plus the start/length of the first bad section we overlap.
7632  */
7633 int md_is_badblock(struct badblocks *bb, sector_t s, int sectors,
7634 		   sector_t *first_bad, int *bad_sectors)
7635 {
7636 	int hi;
7637 	int lo = 0;
7638 	u64 *p = bb->page;
7639 	int rv = 0;
7640 	sector_t target = s + sectors;
7641 	unsigned seq;
7642 
7643 	if (bb->shift > 0) {
7644 		/* round the start down, and the end up */
7645 		s >>= bb->shift;
7646 		target += (1<<bb->shift) - 1;
7647 		target >>= bb->shift;
7648 		sectors = target - s;
7649 	}
7650 	/* 'target' is now the first block after the bad range */
7651 
7652 retry:
7653 	seq = read_seqbegin(&bb->lock);
7654 
7655 	hi = bb->count;
7656 
7657 	/* Binary search between lo and hi for 'target'
7658 	 * i.e. for the last range that starts before 'target'
7659 	 */
7660 	/* INVARIANT: ranges before 'lo' and at-or-after 'hi'
7661 	 * are known not to be the last range before target.
7662 	 * VARIANT: hi-lo is the number of possible
7663 	 * ranges, and decreases until it reaches 1
7664 	 */
7665 	while (hi - lo > 1) {
7666 		int mid = (lo + hi) / 2;
7667 		sector_t a = BB_OFFSET(p[mid]);
7668 		if (a < target)
7669 			/* This could still be the one, earlier ranges
7670 			 * could not. */
7671 			lo = mid;
7672 		else
7673 			/* This and later ranges are definitely out. */
7674 			hi = mid;
7675 	}
7676 	/* 'lo' might be the last that started before target, but 'hi' isn't */
7677 	if (hi > lo) {
7678 		/* need to check all range that end after 's' to see if
7679 		 * any are unacknowledged.
7680 		 */
7681 		while (lo >= 0 &&
7682 		       BB_OFFSET(p[lo]) + BB_LEN(p[lo]) > s) {
7683 			if (BB_OFFSET(p[lo]) < target) {
7684 				/* starts before the end, and finishes after
7685 				 * the start, so they must overlap
7686 				 */
7687 				if (rv != -1 && BB_ACK(p[lo]))
7688 					rv = 1;
7689 				else
7690 					rv = -1;
7691 				*first_bad = BB_OFFSET(p[lo]);
7692 				*bad_sectors = BB_LEN(p[lo]);
7693 			}
7694 			lo--;
7695 		}
7696 	}
7697 
7698 	if (read_seqretry(&bb->lock, seq))
7699 		goto retry;
7700 
7701 	return rv;
7702 }
7703 EXPORT_SYMBOL_GPL(md_is_badblock);
7704 
7705 /*
7706  * Add a range of bad blocks to the table.
7707  * This might extend the table, or might contract it
7708  * if two adjacent ranges can be merged.
7709  * We binary-search to find the 'insertion' point, then
7710  * decide how best to handle it.
7711  */
7712 static int md_set_badblocks(struct badblocks *bb, sector_t s, int sectors,
7713 			    int acknowledged)
7714 {
7715 	u64 *p;
7716 	int lo, hi;
7717 	int rv = 1;
7718 
7719 	if (bb->shift < 0)
7720 		/* badblocks are disabled */
7721 		return 0;
7722 
7723 	if (bb->shift) {
7724 		/* round the start down, and the end up */
7725 		sector_t next = s + sectors;
7726 		s >>= bb->shift;
7727 		next += (1<<bb->shift) - 1;
7728 		next >>= bb->shift;
7729 		sectors = next - s;
7730 	}
7731 
7732 	write_seqlock_irq(&bb->lock);
7733 
7734 	p = bb->page;
7735 	lo = 0;
7736 	hi = bb->count;
7737 	/* Find the last range that starts at-or-before 's' */
7738 	while (hi - lo > 1) {
7739 		int mid = (lo + hi) / 2;
7740 		sector_t a = BB_OFFSET(p[mid]);
7741 		if (a <= s)
7742 			lo = mid;
7743 		else
7744 			hi = mid;
7745 	}
7746 	if (hi > lo && BB_OFFSET(p[lo]) > s)
7747 		hi = lo;
7748 
7749 	if (hi > lo) {
7750 		/* we found a range that might merge with the start
7751 		 * of our new range
7752 		 */
7753 		sector_t a = BB_OFFSET(p[lo]);
7754 		sector_t e = a + BB_LEN(p[lo]);
7755 		int ack = BB_ACK(p[lo]);
7756 		if (e >= s) {
7757 			/* Yes, we can merge with a previous range */
7758 			if (s == a && s + sectors >= e)
7759 				/* new range covers old */
7760 				ack = acknowledged;
7761 			else
7762 				ack = ack && acknowledged;
7763 
7764 			if (e < s + sectors)
7765 				e = s + sectors;
7766 			if (e - a <= BB_MAX_LEN) {
7767 				p[lo] = BB_MAKE(a, e-a, ack);
7768 				s = e;
7769 			} else {
7770 				/* does not all fit in one range,
7771 				 * make p[lo] maximal
7772 				 */
7773 				if (BB_LEN(p[lo]) != BB_MAX_LEN)
7774 					p[lo] = BB_MAKE(a, BB_MAX_LEN, ack);
7775 				s = a + BB_MAX_LEN;
7776 			}
7777 			sectors = e - s;
7778 		}
7779 	}
7780 	if (sectors && hi < bb->count) {
7781 		/* 'hi' points to the first range that starts after 's'.
7782 		 * Maybe we can merge with the start of that range */
7783 		sector_t a = BB_OFFSET(p[hi]);
7784 		sector_t e = a + BB_LEN(p[hi]);
7785 		int ack = BB_ACK(p[hi]);
7786 		if (a <= s + sectors) {
7787 			/* merging is possible */
7788 			if (e <= s + sectors) {
7789 				/* full overlap */
7790 				e = s + sectors;
7791 				ack = acknowledged;
7792 			} else
7793 				ack = ack && acknowledged;
7794 
7795 			a = s;
7796 			if (e - a <= BB_MAX_LEN) {
7797 				p[hi] = BB_MAKE(a, e-a, ack);
7798 				s = e;
7799 			} else {
7800 				p[hi] = BB_MAKE(a, BB_MAX_LEN, ack);
7801 				s = a + BB_MAX_LEN;
7802 			}
7803 			sectors = e - s;
7804 			lo = hi;
7805 			hi++;
7806 		}
7807 	}
7808 	if (sectors == 0 && hi < bb->count) {
7809 		/* we might be able to combine lo and hi */
7810 		/* Note: 's' is at the end of 'lo' */
7811 		sector_t a = BB_OFFSET(p[hi]);
7812 		int lolen = BB_LEN(p[lo]);
7813 		int hilen = BB_LEN(p[hi]);
7814 		int newlen = lolen + hilen - (s - a);
7815 		if (s >= a && newlen < BB_MAX_LEN) {
7816 			/* yes, we can combine them */
7817 			int ack = BB_ACK(p[lo]) && BB_ACK(p[hi]);
7818 			p[lo] = BB_MAKE(BB_OFFSET(p[lo]), newlen, ack);
7819 			memmove(p + hi, p + hi + 1,
7820 				(bb->count - hi - 1) * 8);
7821 			bb->count--;
7822 		}
7823 	}
7824 	while (sectors) {
7825 		/* didn't merge (it all).
7826 		 * Need to add a range just before 'hi' */
7827 		if (bb->count >= MD_MAX_BADBLOCKS) {
7828 			/* No room for more */
7829 			rv = 0;
7830 			break;
7831 		} else {
7832 			int this_sectors = sectors;
7833 			memmove(p + hi + 1, p + hi,
7834 				(bb->count - hi) * 8);
7835 			bb->count++;
7836 
7837 			if (this_sectors > BB_MAX_LEN)
7838 				this_sectors = BB_MAX_LEN;
7839 			p[hi] = BB_MAKE(s, this_sectors, acknowledged);
7840 			sectors -= this_sectors;
7841 			s += this_sectors;
7842 		}
7843 	}
7844 
7845 	bb->changed = 1;
7846 	if (!acknowledged)
7847 		bb->unacked_exist = 1;
7848 	write_sequnlock_irq(&bb->lock);
7849 
7850 	return rv;
7851 }
7852 
7853 int rdev_set_badblocks(struct md_rdev *rdev, sector_t s, int sectors,
7854 		       int acknowledged)
7855 {
7856 	int rv = md_set_badblocks(&rdev->badblocks,
7857 				  s + rdev->data_offset, sectors, acknowledged);
7858 	if (rv) {
7859 		/* Make sure they get written out promptly */
7860 		sysfs_notify_dirent_safe(rdev->sysfs_state);
7861 		set_bit(MD_CHANGE_CLEAN, &rdev->mddev->flags);
7862 		md_wakeup_thread(rdev->mddev->thread);
7863 	}
7864 	return rv;
7865 }
7866 EXPORT_SYMBOL_GPL(rdev_set_badblocks);
7867 
7868 /*
7869  * Remove a range of bad blocks from the table.
7870  * This may involve extending the table if we spilt a region,
7871  * but it must not fail.  So if the table becomes full, we just
7872  * drop the remove request.
7873  */
7874 static int md_clear_badblocks(struct badblocks *bb, sector_t s, int sectors)
7875 {
7876 	u64 *p;
7877 	int lo, hi;
7878 	sector_t target = s + sectors;
7879 	int rv = 0;
7880 
7881 	if (bb->shift > 0) {
7882 		/* When clearing we round the start up and the end down.
7883 		 * This should not matter as the shift should align with
7884 		 * the block size and no rounding should ever be needed.
7885 		 * However it is better the think a block is bad when it
7886 		 * isn't than to think a block is not bad when it is.
7887 		 */
7888 		s += (1<<bb->shift) - 1;
7889 		s >>= bb->shift;
7890 		target >>= bb->shift;
7891 		sectors = target - s;
7892 	}
7893 
7894 	write_seqlock_irq(&bb->lock);
7895 
7896 	p = bb->page;
7897 	lo = 0;
7898 	hi = bb->count;
7899 	/* Find the last range that starts before 'target' */
7900 	while (hi - lo > 1) {
7901 		int mid = (lo + hi) / 2;
7902 		sector_t a = BB_OFFSET(p[mid]);
7903 		if (a < target)
7904 			lo = mid;
7905 		else
7906 			hi = mid;
7907 	}
7908 	if (hi > lo) {
7909 		/* p[lo] is the last range that could overlap the
7910 		 * current range.  Earlier ranges could also overlap,
7911 		 * but only this one can overlap the end of the range.
7912 		 */
7913 		if (BB_OFFSET(p[lo]) + BB_LEN(p[lo]) > target) {
7914 			/* Partial overlap, leave the tail of this range */
7915 			int ack = BB_ACK(p[lo]);
7916 			sector_t a = BB_OFFSET(p[lo]);
7917 			sector_t end = a + BB_LEN(p[lo]);
7918 
7919 			if (a < s) {
7920 				/* we need to split this range */
7921 				if (bb->count >= MD_MAX_BADBLOCKS) {
7922 					rv = 0;
7923 					goto out;
7924 				}
7925 				memmove(p+lo+1, p+lo, (bb->count - lo) * 8);
7926 				bb->count++;
7927 				p[lo] = BB_MAKE(a, s-a, ack);
7928 				lo++;
7929 			}
7930 			p[lo] = BB_MAKE(target, end - target, ack);
7931 			/* there is no longer an overlap */
7932 			hi = lo;
7933 			lo--;
7934 		}
7935 		while (lo >= 0 &&
7936 		       BB_OFFSET(p[lo]) + BB_LEN(p[lo]) > s) {
7937 			/* This range does overlap */
7938 			if (BB_OFFSET(p[lo]) < s) {
7939 				/* Keep the early parts of this range. */
7940 				int ack = BB_ACK(p[lo]);
7941 				sector_t start = BB_OFFSET(p[lo]);
7942 				p[lo] = BB_MAKE(start, s - start, ack);
7943 				/* now low doesn't overlap, so.. */
7944 				break;
7945 			}
7946 			lo--;
7947 		}
7948 		/* 'lo' is strictly before, 'hi' is strictly after,
7949 		 * anything between needs to be discarded
7950 		 */
7951 		if (hi - lo > 1) {
7952 			memmove(p+lo+1, p+hi, (bb->count - hi) * 8);
7953 			bb->count -= (hi - lo - 1);
7954 		}
7955 	}
7956 
7957 	bb->changed = 1;
7958 out:
7959 	write_sequnlock_irq(&bb->lock);
7960 	return rv;
7961 }
7962 
7963 int rdev_clear_badblocks(struct md_rdev *rdev, sector_t s, int sectors)
7964 {
7965 	return md_clear_badblocks(&rdev->badblocks,
7966 				  s + rdev->data_offset,
7967 				  sectors);
7968 }
7969 EXPORT_SYMBOL_GPL(rdev_clear_badblocks);
7970 
7971 /*
7972  * Acknowledge all bad blocks in a list.
7973  * This only succeeds if ->changed is clear.  It is used by
7974  * in-kernel metadata updates
7975  */
7976 void md_ack_all_badblocks(struct badblocks *bb)
7977 {
7978 	if (bb->page == NULL || bb->changed)
7979 		/* no point even trying */
7980 		return;
7981 	write_seqlock_irq(&bb->lock);
7982 
7983 	if (bb->changed == 0) {
7984 		u64 *p = bb->page;
7985 		int i;
7986 		for (i = 0; i < bb->count ; i++) {
7987 			if (!BB_ACK(p[i])) {
7988 				sector_t start = BB_OFFSET(p[i]);
7989 				int len = BB_LEN(p[i]);
7990 				p[i] = BB_MAKE(start, len, 1);
7991 			}
7992 		}
7993 		bb->unacked_exist = 0;
7994 	}
7995 	write_sequnlock_irq(&bb->lock);
7996 }
7997 EXPORT_SYMBOL_GPL(md_ack_all_badblocks);
7998 
7999 /* sysfs access to bad-blocks list.
8000  * We present two files.
8001  * 'bad-blocks' lists sector numbers and lengths of ranges that
8002  *    are recorded as bad.  The list is truncated to fit within
8003  *    the one-page limit of sysfs.
8004  *    Writing "sector length" to this file adds an acknowledged
8005  *    bad block list.
8006  * 'unacknowledged-bad-blocks' lists bad blocks that have not yet
8007  *    been acknowledged.  Writing to this file adds bad blocks
8008  *    without acknowledging them.  This is largely for testing.
8009  */
8010 
8011 static ssize_t
8012 badblocks_show(struct badblocks *bb, char *page, int unack)
8013 {
8014 	size_t len;
8015 	int i;
8016 	u64 *p = bb->page;
8017 	unsigned seq;
8018 
8019 	if (bb->shift < 0)
8020 		return 0;
8021 
8022 retry:
8023 	seq = read_seqbegin(&bb->lock);
8024 
8025 	len = 0;
8026 	i = 0;
8027 
8028 	while (len < PAGE_SIZE && i < bb->count) {
8029 		sector_t s = BB_OFFSET(p[i]);
8030 		unsigned int length = BB_LEN(p[i]);
8031 		int ack = BB_ACK(p[i]);
8032 		i++;
8033 
8034 		if (unack && ack)
8035 			continue;
8036 
8037 		len += snprintf(page+len, PAGE_SIZE-len, "%llu %u\n",
8038 				(unsigned long long)s << bb->shift,
8039 				length << bb->shift);
8040 	}
8041 	if (unack && len == 0)
8042 		bb->unacked_exist = 0;
8043 
8044 	if (read_seqretry(&bb->lock, seq))
8045 		goto retry;
8046 
8047 	return len;
8048 }
8049 
8050 #define DO_DEBUG 1
8051 
8052 static ssize_t
8053 badblocks_store(struct badblocks *bb, const char *page, size_t len, int unack)
8054 {
8055 	unsigned long long sector;
8056 	int length;
8057 	char newline;
8058 #ifdef DO_DEBUG
8059 	/* Allow clearing via sysfs *only* for testing/debugging.
8060 	 * Normally only a successful write may clear a badblock
8061 	 */
8062 	int clear = 0;
8063 	if (page[0] == '-') {
8064 		clear = 1;
8065 		page++;
8066 	}
8067 #endif /* DO_DEBUG */
8068 
8069 	switch (sscanf(page, "%llu %d%c", &sector, &length, &newline)) {
8070 	case 3:
8071 		if (newline != '\n')
8072 			return -EINVAL;
8073 	case 2:
8074 		if (length <= 0)
8075 			return -EINVAL;
8076 		break;
8077 	default:
8078 		return -EINVAL;
8079 	}
8080 
8081 #ifdef DO_DEBUG
8082 	if (clear) {
8083 		md_clear_badblocks(bb, sector, length);
8084 		return len;
8085 	}
8086 #endif /* DO_DEBUG */
8087 	if (md_set_badblocks(bb, sector, length, !unack))
8088 		return len;
8089 	else
8090 		return -ENOSPC;
8091 }
8092 
8093 static int md_notify_reboot(struct notifier_block *this,
8094 			    unsigned long code, void *x)
8095 {
8096 	struct list_head *tmp;
8097 	struct mddev *mddev;
8098 	int need_delay = 0;
8099 
8100 	if ((code == SYS_DOWN) || (code == SYS_HALT) || (code == SYS_POWER_OFF)) {
8101 
8102 		printk(KERN_INFO "md: stopping all md devices.\n");
8103 
8104 		for_each_mddev(mddev, tmp) {
8105 			if (mddev_trylock(mddev)) {
8106 				/* Force a switch to readonly even array
8107 				 * appears to still be in use.  Hence
8108 				 * the '100'.
8109 				 */
8110 				md_set_readonly(mddev, 100);
8111 				mddev_unlock(mddev);
8112 			}
8113 			need_delay = 1;
8114 		}
8115 		/*
8116 		 * certain more exotic SCSI devices are known to be
8117 		 * volatile wrt too early system reboots. While the
8118 		 * right place to handle this issue is the given
8119 		 * driver, we do want to have a safe RAID driver ...
8120 		 */
8121 		if (need_delay)
8122 			mdelay(1000*1);
8123 	}
8124 	return NOTIFY_DONE;
8125 }
8126 
8127 static struct notifier_block md_notifier = {
8128 	.notifier_call	= md_notify_reboot,
8129 	.next		= NULL,
8130 	.priority	= INT_MAX, /* before any real devices */
8131 };
8132 
8133 static void md_geninit(void)
8134 {
8135 	pr_debug("md: sizeof(mdp_super_t) = %d\n", (int)sizeof(mdp_super_t));
8136 
8137 	proc_create("mdstat", S_IRUGO, NULL, &md_seq_fops);
8138 }
8139 
8140 static int __init md_init(void)
8141 {
8142 	int ret = -ENOMEM;
8143 
8144 	md_wq = alloc_workqueue("md", WQ_MEM_RECLAIM, 0);
8145 	if (!md_wq)
8146 		goto err_wq;
8147 
8148 	md_misc_wq = alloc_workqueue("md_misc", 0, 0);
8149 	if (!md_misc_wq)
8150 		goto err_misc_wq;
8151 
8152 	if ((ret = register_blkdev(MD_MAJOR, "md")) < 0)
8153 		goto err_md;
8154 
8155 	if ((ret = register_blkdev(0, "mdp")) < 0)
8156 		goto err_mdp;
8157 	mdp_major = ret;
8158 
8159 	blk_register_region(MKDEV(MD_MAJOR, 0), 1UL<<MINORBITS, THIS_MODULE,
8160 			    md_probe, NULL, NULL);
8161 	blk_register_region(MKDEV(mdp_major, 0), 1UL<<MINORBITS, THIS_MODULE,
8162 			    md_probe, NULL, NULL);
8163 
8164 	register_reboot_notifier(&md_notifier);
8165 	raid_table_header = register_sysctl_table(raid_root_table);
8166 
8167 	md_geninit();
8168 	return 0;
8169 
8170 err_mdp:
8171 	unregister_blkdev(MD_MAJOR, "md");
8172 err_md:
8173 	destroy_workqueue(md_misc_wq);
8174 err_misc_wq:
8175 	destroy_workqueue(md_wq);
8176 err_wq:
8177 	return ret;
8178 }
8179 
8180 #ifndef MODULE
8181 
8182 /*
8183  * Searches all registered partitions for autorun RAID arrays
8184  * at boot time.
8185  */
8186 
8187 static LIST_HEAD(all_detected_devices);
8188 struct detected_devices_node {
8189 	struct list_head list;
8190 	dev_t dev;
8191 };
8192 
8193 void md_autodetect_dev(dev_t dev)
8194 {
8195 	struct detected_devices_node *node_detected_dev;
8196 
8197 	node_detected_dev = kzalloc(sizeof(*node_detected_dev), GFP_KERNEL);
8198 	if (node_detected_dev) {
8199 		node_detected_dev->dev = dev;
8200 		list_add_tail(&node_detected_dev->list, &all_detected_devices);
8201 	} else {
8202 		printk(KERN_CRIT "md: md_autodetect_dev: kzalloc failed"
8203 			", skipping dev(%d,%d)\n", MAJOR(dev), MINOR(dev));
8204 	}
8205 }
8206 
8207 
8208 static void autostart_arrays(int part)
8209 {
8210 	struct md_rdev *rdev;
8211 	struct detected_devices_node *node_detected_dev;
8212 	dev_t dev;
8213 	int i_scanned, i_passed;
8214 
8215 	i_scanned = 0;
8216 	i_passed = 0;
8217 
8218 	printk(KERN_INFO "md: Autodetecting RAID arrays.\n");
8219 
8220 	while (!list_empty(&all_detected_devices) && i_scanned < INT_MAX) {
8221 		i_scanned++;
8222 		node_detected_dev = list_entry(all_detected_devices.next,
8223 					struct detected_devices_node, list);
8224 		list_del(&node_detected_dev->list);
8225 		dev = node_detected_dev->dev;
8226 		kfree(node_detected_dev);
8227 		rdev = md_import_device(dev,0, 90);
8228 		if (IS_ERR(rdev))
8229 			continue;
8230 
8231 		if (test_bit(Faulty, &rdev->flags)) {
8232 			MD_BUG();
8233 			continue;
8234 		}
8235 		set_bit(AutoDetected, &rdev->flags);
8236 		list_add(&rdev->same_set, &pending_raid_disks);
8237 		i_passed++;
8238 	}
8239 
8240 	printk(KERN_INFO "md: Scanned %d and added %d devices.\n",
8241 						i_scanned, i_passed);
8242 
8243 	autorun_devices(part);
8244 }
8245 
8246 #endif /* !MODULE */
8247 
8248 static __exit void md_exit(void)
8249 {
8250 	struct mddev *mddev;
8251 	struct list_head *tmp;
8252 
8253 	blk_unregister_region(MKDEV(MD_MAJOR,0), 1U << MINORBITS);
8254 	blk_unregister_region(MKDEV(mdp_major,0), 1U << MINORBITS);
8255 
8256 	unregister_blkdev(MD_MAJOR,"md");
8257 	unregister_blkdev(mdp_major, "mdp");
8258 	unregister_reboot_notifier(&md_notifier);
8259 	unregister_sysctl_table(raid_table_header);
8260 	remove_proc_entry("mdstat", NULL);
8261 	for_each_mddev(mddev, tmp) {
8262 		export_array(mddev);
8263 		mddev->hold_active = 0;
8264 	}
8265 	destroy_workqueue(md_misc_wq);
8266 	destroy_workqueue(md_wq);
8267 }
8268 
8269 subsys_initcall(md_init);
8270 module_exit(md_exit)
8271 
8272 static int get_ro(char *buffer, struct kernel_param *kp)
8273 {
8274 	return sprintf(buffer, "%d", start_readonly);
8275 }
8276 static int set_ro(const char *val, struct kernel_param *kp)
8277 {
8278 	char *e;
8279 	int num = simple_strtoul(val, &e, 10);
8280 	if (*val && (*e == '\0' || *e == '\n')) {
8281 		start_readonly = num;
8282 		return 0;
8283 	}
8284 	return -EINVAL;
8285 }
8286 
8287 module_param_call(start_ro, set_ro, get_ro, NULL, S_IRUSR|S_IWUSR);
8288 module_param(start_dirty_degraded, int, S_IRUGO|S_IWUSR);
8289 
8290 module_param_call(new_array, add_named_array, NULL, NULL, S_IWUSR);
8291 
8292 EXPORT_SYMBOL(register_md_personality);
8293 EXPORT_SYMBOL(unregister_md_personality);
8294 EXPORT_SYMBOL(md_error);
8295 EXPORT_SYMBOL(md_done_sync);
8296 EXPORT_SYMBOL(md_write_start);
8297 EXPORT_SYMBOL(md_write_end);
8298 EXPORT_SYMBOL(md_register_thread);
8299 EXPORT_SYMBOL(md_unregister_thread);
8300 EXPORT_SYMBOL(md_wakeup_thread);
8301 EXPORT_SYMBOL(md_check_recovery);
8302 MODULE_LICENSE("GPL");
8303 MODULE_DESCRIPTION("MD RAID framework");
8304 MODULE_ALIAS("md");
8305 MODULE_ALIAS_BLOCKDEV_MAJOR(MD_MAJOR);
8306