xref: /linux/drivers/md/md.c (revision 26b0d14106954ae46d2f4f7eec3481828a210f7d)
1 /*
2    md.c : Multiple Devices driver for Linux
3 	  Copyright (C) 1998, 1999, 2000 Ingo Molnar
4 
5      completely rewritten, based on the MD driver code from Marc Zyngier
6 
7    Changes:
8 
9    - RAID-1/RAID-5 extensions by Miguel de Icaza, Gadi Oxman, Ingo Molnar
10    - RAID-6 extensions by H. Peter Anvin <hpa@zytor.com>
11    - boot support for linear and striped mode by Harald Hoyer <HarryH@Royal.Net>
12    - kerneld support by Boris Tobotras <boris@xtalk.msk.su>
13    - kmod support by: Cyrus Durgin
14    - RAID0 bugfixes: Mark Anthony Lisher <markal@iname.com>
15    - Devfs support by Richard Gooch <rgooch@atnf.csiro.au>
16 
17    - lots of fixes and improvements to the RAID1/RAID5 and generic
18      RAID code (such as request based resynchronization):
19 
20      Neil Brown <neilb@cse.unsw.edu.au>.
21 
22    - persistent bitmap code
23      Copyright (C) 2003-2004, Paul Clements, SteelEye Technology, Inc.
24 
25    This program is free software; you can redistribute it and/or modify
26    it under the terms of the GNU General Public License as published by
27    the Free Software Foundation; either version 2, or (at your option)
28    any later version.
29 
30    You should have received a copy of the GNU General Public License
31    (for example /usr/src/linux/COPYING); if not, write to the Free
32    Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
33 */
34 
35 #include <linux/kthread.h>
36 #include <linux/blkdev.h>
37 #include <linux/sysctl.h>
38 #include <linux/seq_file.h>
39 #include <linux/fs.h>
40 #include <linux/poll.h>
41 #include <linux/ctype.h>
42 #include <linux/string.h>
43 #include <linux/hdreg.h>
44 #include <linux/proc_fs.h>
45 #include <linux/random.h>
46 #include <linux/module.h>
47 #include <linux/reboot.h>
48 #include <linux/file.h>
49 #include <linux/compat.h>
50 #include <linux/delay.h>
51 #include <linux/raid/md_p.h>
52 #include <linux/raid/md_u.h>
53 #include <linux/slab.h>
54 #include "md.h"
55 #include "bitmap.h"
56 
57 #ifndef MODULE
58 static void autostart_arrays(int part);
59 #endif
60 
61 /* pers_list is a list of registered personalities protected
62  * by pers_lock.
63  * pers_lock does extra service to protect accesses to
64  * mddev->thread when the mutex cannot be held.
65  */
66 static LIST_HEAD(pers_list);
67 static DEFINE_SPINLOCK(pers_lock);
68 
69 static void md_print_devices(void);
70 
71 static DECLARE_WAIT_QUEUE_HEAD(resync_wait);
72 static struct workqueue_struct *md_wq;
73 static struct workqueue_struct *md_misc_wq;
74 
75 #define MD_BUG(x...) { printk("md: bug in file %s, line %d\n", __FILE__, __LINE__); md_print_devices(); }
76 
77 /*
78  * Default number of read corrections we'll attempt on an rdev
79  * before ejecting it from the array. We divide the read error
80  * count by 2 for every hour elapsed between read errors.
81  */
82 #define MD_DEFAULT_MAX_CORRECTED_READ_ERRORS 20
83 /*
84  * Current RAID-1,4,5 parallel reconstruction 'guaranteed speed limit'
85  * is 1000 KB/sec, so the extra system load does not show up that much.
86  * Increase it if you want to have more _guaranteed_ speed. Note that
87  * the RAID driver will use the maximum available bandwidth if the IO
88  * subsystem is idle. There is also an 'absolute maximum' reconstruction
89  * speed limit - in case reconstruction slows down your system despite
90  * idle IO detection.
91  *
92  * you can change it via /proc/sys/dev/raid/speed_limit_min and _max.
93  * or /sys/block/mdX/md/sync_speed_{min,max}
94  */
95 
96 static int sysctl_speed_limit_min = 1000;
97 static int sysctl_speed_limit_max = 200000;
98 static inline int speed_min(struct mddev *mddev)
99 {
100 	return mddev->sync_speed_min ?
101 		mddev->sync_speed_min : sysctl_speed_limit_min;
102 }
103 
104 static inline int speed_max(struct mddev *mddev)
105 {
106 	return mddev->sync_speed_max ?
107 		mddev->sync_speed_max : sysctl_speed_limit_max;
108 }
109 
110 static struct ctl_table_header *raid_table_header;
111 
112 static ctl_table raid_table[] = {
113 	{
114 		.procname	= "speed_limit_min",
115 		.data		= &sysctl_speed_limit_min,
116 		.maxlen		= sizeof(int),
117 		.mode		= S_IRUGO|S_IWUSR,
118 		.proc_handler	= proc_dointvec,
119 	},
120 	{
121 		.procname	= "speed_limit_max",
122 		.data		= &sysctl_speed_limit_max,
123 		.maxlen		= sizeof(int),
124 		.mode		= S_IRUGO|S_IWUSR,
125 		.proc_handler	= proc_dointvec,
126 	},
127 	{ }
128 };
129 
130 static ctl_table raid_dir_table[] = {
131 	{
132 		.procname	= "raid",
133 		.maxlen		= 0,
134 		.mode		= S_IRUGO|S_IXUGO,
135 		.child		= raid_table,
136 	},
137 	{ }
138 };
139 
140 static ctl_table raid_root_table[] = {
141 	{
142 		.procname	= "dev",
143 		.maxlen		= 0,
144 		.mode		= 0555,
145 		.child		= raid_dir_table,
146 	},
147 	{  }
148 };
149 
150 static const struct block_device_operations md_fops;
151 
152 static int start_readonly;
153 
154 /* bio_clone_mddev
155  * like bio_clone, but with a local bio set
156  */
157 
158 static void mddev_bio_destructor(struct bio *bio)
159 {
160 	struct mddev *mddev, **mddevp;
161 
162 	mddevp = (void*)bio;
163 	mddev = mddevp[-1];
164 
165 	bio_free(bio, mddev->bio_set);
166 }
167 
168 struct bio *bio_alloc_mddev(gfp_t gfp_mask, int nr_iovecs,
169 			    struct mddev *mddev)
170 {
171 	struct bio *b;
172 	struct mddev **mddevp;
173 
174 	if (!mddev || !mddev->bio_set)
175 		return bio_alloc(gfp_mask, nr_iovecs);
176 
177 	b = bio_alloc_bioset(gfp_mask, nr_iovecs,
178 			     mddev->bio_set);
179 	if (!b)
180 		return NULL;
181 	mddevp = (void*)b;
182 	mddevp[-1] = mddev;
183 	b->bi_destructor = mddev_bio_destructor;
184 	return b;
185 }
186 EXPORT_SYMBOL_GPL(bio_alloc_mddev);
187 
188 struct bio *bio_clone_mddev(struct bio *bio, gfp_t gfp_mask,
189 			    struct mddev *mddev)
190 {
191 	struct bio *b;
192 	struct mddev **mddevp;
193 
194 	if (!mddev || !mddev->bio_set)
195 		return bio_clone(bio, gfp_mask);
196 
197 	b = bio_alloc_bioset(gfp_mask, bio->bi_max_vecs,
198 			     mddev->bio_set);
199 	if (!b)
200 		return NULL;
201 	mddevp = (void*)b;
202 	mddevp[-1] = mddev;
203 	b->bi_destructor = mddev_bio_destructor;
204 	__bio_clone(b, bio);
205 	if (bio_integrity(bio)) {
206 		int ret;
207 
208 		ret = bio_integrity_clone(b, bio, gfp_mask, mddev->bio_set);
209 
210 		if (ret < 0) {
211 			bio_put(b);
212 			return NULL;
213 		}
214 	}
215 
216 	return b;
217 }
218 EXPORT_SYMBOL_GPL(bio_clone_mddev);
219 
220 void md_trim_bio(struct bio *bio, int offset, int size)
221 {
222 	/* 'bio' is a cloned bio which we need to trim to match
223 	 * the given offset and size.
224 	 * This requires adjusting bi_sector, bi_size, and bi_io_vec
225 	 */
226 	int i;
227 	struct bio_vec *bvec;
228 	int sofar = 0;
229 
230 	size <<= 9;
231 	if (offset == 0 && size == bio->bi_size)
232 		return;
233 
234 	bio->bi_sector += offset;
235 	bio->bi_size = size;
236 	offset <<= 9;
237 	clear_bit(BIO_SEG_VALID, &bio->bi_flags);
238 
239 	while (bio->bi_idx < bio->bi_vcnt &&
240 	       bio->bi_io_vec[bio->bi_idx].bv_len <= offset) {
241 		/* remove this whole bio_vec */
242 		offset -= bio->bi_io_vec[bio->bi_idx].bv_len;
243 		bio->bi_idx++;
244 	}
245 	if (bio->bi_idx < bio->bi_vcnt) {
246 		bio->bi_io_vec[bio->bi_idx].bv_offset += offset;
247 		bio->bi_io_vec[bio->bi_idx].bv_len -= offset;
248 	}
249 	/* avoid any complications with bi_idx being non-zero*/
250 	if (bio->bi_idx) {
251 		memmove(bio->bi_io_vec, bio->bi_io_vec+bio->bi_idx,
252 			(bio->bi_vcnt - bio->bi_idx) * sizeof(struct bio_vec));
253 		bio->bi_vcnt -= bio->bi_idx;
254 		bio->bi_idx = 0;
255 	}
256 	/* Make sure vcnt and last bv are not too big */
257 	bio_for_each_segment(bvec, bio, i) {
258 		if (sofar + bvec->bv_len > size)
259 			bvec->bv_len = size - sofar;
260 		if (bvec->bv_len == 0) {
261 			bio->bi_vcnt = i;
262 			break;
263 		}
264 		sofar += bvec->bv_len;
265 	}
266 }
267 EXPORT_SYMBOL_GPL(md_trim_bio);
268 
269 /*
270  * We have a system wide 'event count' that is incremented
271  * on any 'interesting' event, and readers of /proc/mdstat
272  * can use 'poll' or 'select' to find out when the event
273  * count increases.
274  *
275  * Events are:
276  *  start array, stop array, error, add device, remove device,
277  *  start build, activate spare
278  */
279 static DECLARE_WAIT_QUEUE_HEAD(md_event_waiters);
280 static atomic_t md_event_count;
281 void md_new_event(struct mddev *mddev)
282 {
283 	atomic_inc(&md_event_count);
284 	wake_up(&md_event_waiters);
285 }
286 EXPORT_SYMBOL_GPL(md_new_event);
287 
288 /* Alternate version that can be called from interrupts
289  * when calling sysfs_notify isn't needed.
290  */
291 static void md_new_event_inintr(struct mddev *mddev)
292 {
293 	atomic_inc(&md_event_count);
294 	wake_up(&md_event_waiters);
295 }
296 
297 /*
298  * Enables to iterate over all existing md arrays
299  * all_mddevs_lock protects this list.
300  */
301 static LIST_HEAD(all_mddevs);
302 static DEFINE_SPINLOCK(all_mddevs_lock);
303 
304 
305 /*
306  * iterates through all used mddevs in the system.
307  * We take care to grab the all_mddevs_lock whenever navigating
308  * the list, and to always hold a refcount when unlocked.
309  * Any code which breaks out of this loop while own
310  * a reference to the current mddev and must mddev_put it.
311  */
312 #define for_each_mddev(_mddev,_tmp)					\
313 									\
314 	for (({ spin_lock(&all_mddevs_lock); 				\
315 		_tmp = all_mddevs.next;					\
316 		_mddev = NULL;});					\
317 	     ({ if (_tmp != &all_mddevs)				\
318 			mddev_get(list_entry(_tmp, struct mddev, all_mddevs));\
319 		spin_unlock(&all_mddevs_lock);				\
320 		if (_mddev) mddev_put(_mddev);				\
321 		_mddev = list_entry(_tmp, struct mddev, all_mddevs);	\
322 		_tmp != &all_mddevs;});					\
323 	     ({ spin_lock(&all_mddevs_lock);				\
324 		_tmp = _tmp->next;})					\
325 		)
326 
327 
328 /* Rather than calling directly into the personality make_request function,
329  * IO requests come here first so that we can check if the device is
330  * being suspended pending a reconfiguration.
331  * We hold a refcount over the call to ->make_request.  By the time that
332  * call has finished, the bio has been linked into some internal structure
333  * and so is visible to ->quiesce(), so we don't need the refcount any more.
334  */
335 static void md_make_request(struct request_queue *q, struct bio *bio)
336 {
337 	const int rw = bio_data_dir(bio);
338 	struct mddev *mddev = q->queuedata;
339 	int cpu;
340 	unsigned int sectors;
341 
342 	if (mddev == NULL || mddev->pers == NULL
343 	    || !mddev->ready) {
344 		bio_io_error(bio);
345 		return;
346 	}
347 	smp_rmb(); /* Ensure implications of  'active' are visible */
348 	rcu_read_lock();
349 	if (mddev->suspended) {
350 		DEFINE_WAIT(__wait);
351 		for (;;) {
352 			prepare_to_wait(&mddev->sb_wait, &__wait,
353 					TASK_UNINTERRUPTIBLE);
354 			if (!mddev->suspended)
355 				break;
356 			rcu_read_unlock();
357 			schedule();
358 			rcu_read_lock();
359 		}
360 		finish_wait(&mddev->sb_wait, &__wait);
361 	}
362 	atomic_inc(&mddev->active_io);
363 	rcu_read_unlock();
364 
365 	/*
366 	 * save the sectors now since our bio can
367 	 * go away inside make_request
368 	 */
369 	sectors = bio_sectors(bio);
370 	mddev->pers->make_request(mddev, bio);
371 
372 	cpu = part_stat_lock();
373 	part_stat_inc(cpu, &mddev->gendisk->part0, ios[rw]);
374 	part_stat_add(cpu, &mddev->gendisk->part0, sectors[rw], sectors);
375 	part_stat_unlock();
376 
377 	if (atomic_dec_and_test(&mddev->active_io) && mddev->suspended)
378 		wake_up(&mddev->sb_wait);
379 }
380 
381 /* mddev_suspend makes sure no new requests are submitted
382  * to the device, and that any requests that have been submitted
383  * are completely handled.
384  * Once ->stop is called and completes, the module will be completely
385  * unused.
386  */
387 void mddev_suspend(struct mddev *mddev)
388 {
389 	BUG_ON(mddev->suspended);
390 	mddev->suspended = 1;
391 	synchronize_rcu();
392 	wait_event(mddev->sb_wait, atomic_read(&mddev->active_io) == 0);
393 	mddev->pers->quiesce(mddev, 1);
394 
395 	del_timer_sync(&mddev->safemode_timer);
396 }
397 EXPORT_SYMBOL_GPL(mddev_suspend);
398 
399 void mddev_resume(struct mddev *mddev)
400 {
401 	mddev->suspended = 0;
402 	wake_up(&mddev->sb_wait);
403 	mddev->pers->quiesce(mddev, 0);
404 
405 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
406 	md_wakeup_thread(mddev->thread);
407 	md_wakeup_thread(mddev->sync_thread); /* possibly kick off a reshape */
408 }
409 EXPORT_SYMBOL_GPL(mddev_resume);
410 
411 int mddev_congested(struct mddev *mddev, int bits)
412 {
413 	return mddev->suspended;
414 }
415 EXPORT_SYMBOL(mddev_congested);
416 
417 /*
418  * Generic flush handling for md
419  */
420 
421 static void md_end_flush(struct bio *bio, int err)
422 {
423 	struct md_rdev *rdev = bio->bi_private;
424 	struct mddev *mddev = rdev->mddev;
425 
426 	rdev_dec_pending(rdev, mddev);
427 
428 	if (atomic_dec_and_test(&mddev->flush_pending)) {
429 		/* The pre-request flush has finished */
430 		queue_work(md_wq, &mddev->flush_work);
431 	}
432 	bio_put(bio);
433 }
434 
435 static void md_submit_flush_data(struct work_struct *ws);
436 
437 static void submit_flushes(struct work_struct *ws)
438 {
439 	struct mddev *mddev = container_of(ws, struct mddev, flush_work);
440 	struct md_rdev *rdev;
441 
442 	INIT_WORK(&mddev->flush_work, md_submit_flush_data);
443 	atomic_set(&mddev->flush_pending, 1);
444 	rcu_read_lock();
445 	rdev_for_each_rcu(rdev, mddev)
446 		if (rdev->raid_disk >= 0 &&
447 		    !test_bit(Faulty, &rdev->flags)) {
448 			/* Take two references, one is dropped
449 			 * when request finishes, one after
450 			 * we reclaim rcu_read_lock
451 			 */
452 			struct bio *bi;
453 			atomic_inc(&rdev->nr_pending);
454 			atomic_inc(&rdev->nr_pending);
455 			rcu_read_unlock();
456 			bi = bio_alloc_mddev(GFP_NOIO, 0, mddev);
457 			bi->bi_end_io = md_end_flush;
458 			bi->bi_private = rdev;
459 			bi->bi_bdev = rdev->bdev;
460 			atomic_inc(&mddev->flush_pending);
461 			submit_bio(WRITE_FLUSH, bi);
462 			rcu_read_lock();
463 			rdev_dec_pending(rdev, mddev);
464 		}
465 	rcu_read_unlock();
466 	if (atomic_dec_and_test(&mddev->flush_pending))
467 		queue_work(md_wq, &mddev->flush_work);
468 }
469 
470 static void md_submit_flush_data(struct work_struct *ws)
471 {
472 	struct mddev *mddev = container_of(ws, struct mddev, flush_work);
473 	struct bio *bio = mddev->flush_bio;
474 
475 	if (bio->bi_size == 0)
476 		/* an empty barrier - all done */
477 		bio_endio(bio, 0);
478 	else {
479 		bio->bi_rw &= ~REQ_FLUSH;
480 		mddev->pers->make_request(mddev, bio);
481 	}
482 
483 	mddev->flush_bio = NULL;
484 	wake_up(&mddev->sb_wait);
485 }
486 
487 void md_flush_request(struct mddev *mddev, struct bio *bio)
488 {
489 	spin_lock_irq(&mddev->write_lock);
490 	wait_event_lock_irq(mddev->sb_wait,
491 			    !mddev->flush_bio,
492 			    mddev->write_lock, /*nothing*/);
493 	mddev->flush_bio = bio;
494 	spin_unlock_irq(&mddev->write_lock);
495 
496 	INIT_WORK(&mddev->flush_work, submit_flushes);
497 	queue_work(md_wq, &mddev->flush_work);
498 }
499 EXPORT_SYMBOL(md_flush_request);
500 
501 /* Support for plugging.
502  * This mirrors the plugging support in request_queue, but does not
503  * require having a whole queue or request structures.
504  * We allocate an md_plug_cb for each md device and each thread it gets
505  * plugged on.  This links tot the private plug_handle structure in the
506  * personality data where we keep a count of the number of outstanding
507  * plugs so other code can see if a plug is active.
508  */
509 struct md_plug_cb {
510 	struct blk_plug_cb cb;
511 	struct mddev *mddev;
512 };
513 
514 static void plugger_unplug(struct blk_plug_cb *cb)
515 {
516 	struct md_plug_cb *mdcb = container_of(cb, struct md_plug_cb, cb);
517 	if (atomic_dec_and_test(&mdcb->mddev->plug_cnt))
518 		md_wakeup_thread(mdcb->mddev->thread);
519 	kfree(mdcb);
520 }
521 
522 /* Check that an unplug wakeup will come shortly.
523  * If not, wakeup the md thread immediately
524  */
525 int mddev_check_plugged(struct mddev *mddev)
526 {
527 	struct blk_plug *plug = current->plug;
528 	struct md_plug_cb *mdcb;
529 
530 	if (!plug)
531 		return 0;
532 
533 	list_for_each_entry(mdcb, &plug->cb_list, cb.list) {
534 		if (mdcb->cb.callback == plugger_unplug &&
535 		    mdcb->mddev == mddev) {
536 			/* Already on the list, move to top */
537 			if (mdcb != list_first_entry(&plug->cb_list,
538 						    struct md_plug_cb,
539 						    cb.list))
540 				list_move(&mdcb->cb.list, &plug->cb_list);
541 			return 1;
542 		}
543 	}
544 	/* Not currently on the callback list */
545 	mdcb = kmalloc(sizeof(*mdcb), GFP_ATOMIC);
546 	if (!mdcb)
547 		return 0;
548 
549 	mdcb->mddev = mddev;
550 	mdcb->cb.callback = plugger_unplug;
551 	atomic_inc(&mddev->plug_cnt);
552 	list_add(&mdcb->cb.list, &plug->cb_list);
553 	return 1;
554 }
555 EXPORT_SYMBOL_GPL(mddev_check_plugged);
556 
557 static inline struct mddev *mddev_get(struct mddev *mddev)
558 {
559 	atomic_inc(&mddev->active);
560 	return mddev;
561 }
562 
563 static void mddev_delayed_delete(struct work_struct *ws);
564 
565 static void mddev_put(struct mddev *mddev)
566 {
567 	struct bio_set *bs = NULL;
568 
569 	if (!atomic_dec_and_lock(&mddev->active, &all_mddevs_lock))
570 		return;
571 	if (!mddev->raid_disks && list_empty(&mddev->disks) &&
572 	    mddev->ctime == 0 && !mddev->hold_active) {
573 		/* Array is not configured at all, and not held active,
574 		 * so destroy it */
575 		list_del_init(&mddev->all_mddevs);
576 		bs = mddev->bio_set;
577 		mddev->bio_set = NULL;
578 		if (mddev->gendisk) {
579 			/* We did a probe so need to clean up.  Call
580 			 * queue_work inside the spinlock so that
581 			 * flush_workqueue() after mddev_find will
582 			 * succeed in waiting for the work to be done.
583 			 */
584 			INIT_WORK(&mddev->del_work, mddev_delayed_delete);
585 			queue_work(md_misc_wq, &mddev->del_work);
586 		} else
587 			kfree(mddev);
588 	}
589 	spin_unlock(&all_mddevs_lock);
590 	if (bs)
591 		bioset_free(bs);
592 }
593 
594 void mddev_init(struct mddev *mddev)
595 {
596 	mutex_init(&mddev->open_mutex);
597 	mutex_init(&mddev->reconfig_mutex);
598 	mutex_init(&mddev->bitmap_info.mutex);
599 	INIT_LIST_HEAD(&mddev->disks);
600 	INIT_LIST_HEAD(&mddev->all_mddevs);
601 	init_timer(&mddev->safemode_timer);
602 	atomic_set(&mddev->active, 1);
603 	atomic_set(&mddev->openers, 0);
604 	atomic_set(&mddev->active_io, 0);
605 	atomic_set(&mddev->plug_cnt, 0);
606 	spin_lock_init(&mddev->write_lock);
607 	atomic_set(&mddev->flush_pending, 0);
608 	init_waitqueue_head(&mddev->sb_wait);
609 	init_waitqueue_head(&mddev->recovery_wait);
610 	mddev->reshape_position = MaxSector;
611 	mddev->reshape_backwards = 0;
612 	mddev->resync_min = 0;
613 	mddev->resync_max = MaxSector;
614 	mddev->level = LEVEL_NONE;
615 }
616 EXPORT_SYMBOL_GPL(mddev_init);
617 
618 static struct mddev * mddev_find(dev_t unit)
619 {
620 	struct mddev *mddev, *new = NULL;
621 
622 	if (unit && MAJOR(unit) != MD_MAJOR)
623 		unit &= ~((1<<MdpMinorShift)-1);
624 
625  retry:
626 	spin_lock(&all_mddevs_lock);
627 
628 	if (unit) {
629 		list_for_each_entry(mddev, &all_mddevs, all_mddevs)
630 			if (mddev->unit == unit) {
631 				mddev_get(mddev);
632 				spin_unlock(&all_mddevs_lock);
633 				kfree(new);
634 				return mddev;
635 			}
636 
637 		if (new) {
638 			list_add(&new->all_mddevs, &all_mddevs);
639 			spin_unlock(&all_mddevs_lock);
640 			new->hold_active = UNTIL_IOCTL;
641 			return new;
642 		}
643 	} else if (new) {
644 		/* find an unused unit number */
645 		static int next_minor = 512;
646 		int start = next_minor;
647 		int is_free = 0;
648 		int dev = 0;
649 		while (!is_free) {
650 			dev = MKDEV(MD_MAJOR, next_minor);
651 			next_minor++;
652 			if (next_minor > MINORMASK)
653 				next_minor = 0;
654 			if (next_minor == start) {
655 				/* Oh dear, all in use. */
656 				spin_unlock(&all_mddevs_lock);
657 				kfree(new);
658 				return NULL;
659 			}
660 
661 			is_free = 1;
662 			list_for_each_entry(mddev, &all_mddevs, all_mddevs)
663 				if (mddev->unit == dev) {
664 					is_free = 0;
665 					break;
666 				}
667 		}
668 		new->unit = dev;
669 		new->md_minor = MINOR(dev);
670 		new->hold_active = UNTIL_STOP;
671 		list_add(&new->all_mddevs, &all_mddevs);
672 		spin_unlock(&all_mddevs_lock);
673 		return new;
674 	}
675 	spin_unlock(&all_mddevs_lock);
676 
677 	new = kzalloc(sizeof(*new), GFP_KERNEL);
678 	if (!new)
679 		return NULL;
680 
681 	new->unit = unit;
682 	if (MAJOR(unit) == MD_MAJOR)
683 		new->md_minor = MINOR(unit);
684 	else
685 		new->md_minor = MINOR(unit) >> MdpMinorShift;
686 
687 	mddev_init(new);
688 
689 	goto retry;
690 }
691 
692 static inline int mddev_lock(struct mddev * mddev)
693 {
694 	return mutex_lock_interruptible(&mddev->reconfig_mutex);
695 }
696 
697 static inline int mddev_is_locked(struct mddev *mddev)
698 {
699 	return mutex_is_locked(&mddev->reconfig_mutex);
700 }
701 
702 static inline int mddev_trylock(struct mddev * mddev)
703 {
704 	return mutex_trylock(&mddev->reconfig_mutex);
705 }
706 
707 static struct attribute_group md_redundancy_group;
708 
709 static void mddev_unlock(struct mddev * mddev)
710 {
711 	if (mddev->to_remove) {
712 		/* These cannot be removed under reconfig_mutex as
713 		 * an access to the files will try to take reconfig_mutex
714 		 * while holding the file unremovable, which leads to
715 		 * a deadlock.
716 		 * So hold set sysfs_active while the remove in happeing,
717 		 * and anything else which might set ->to_remove or my
718 		 * otherwise change the sysfs namespace will fail with
719 		 * -EBUSY if sysfs_active is still set.
720 		 * We set sysfs_active under reconfig_mutex and elsewhere
721 		 * test it under the same mutex to ensure its correct value
722 		 * is seen.
723 		 */
724 		struct attribute_group *to_remove = mddev->to_remove;
725 		mddev->to_remove = NULL;
726 		mddev->sysfs_active = 1;
727 		mutex_unlock(&mddev->reconfig_mutex);
728 
729 		if (mddev->kobj.sd) {
730 			if (to_remove != &md_redundancy_group)
731 				sysfs_remove_group(&mddev->kobj, to_remove);
732 			if (mddev->pers == NULL ||
733 			    mddev->pers->sync_request == NULL) {
734 				sysfs_remove_group(&mddev->kobj, &md_redundancy_group);
735 				if (mddev->sysfs_action)
736 					sysfs_put(mddev->sysfs_action);
737 				mddev->sysfs_action = NULL;
738 			}
739 		}
740 		mddev->sysfs_active = 0;
741 	} else
742 		mutex_unlock(&mddev->reconfig_mutex);
743 
744 	/* As we've dropped the mutex we need a spinlock to
745 	 * make sure the thread doesn't disappear
746 	 */
747 	spin_lock(&pers_lock);
748 	md_wakeup_thread(mddev->thread);
749 	spin_unlock(&pers_lock);
750 }
751 
752 static struct md_rdev * find_rdev_nr(struct mddev *mddev, int nr)
753 {
754 	struct md_rdev *rdev;
755 
756 	rdev_for_each(rdev, mddev)
757 		if (rdev->desc_nr == nr)
758 			return rdev;
759 
760 	return NULL;
761 }
762 
763 static struct md_rdev * find_rdev(struct mddev * mddev, dev_t dev)
764 {
765 	struct md_rdev *rdev;
766 
767 	rdev_for_each(rdev, mddev)
768 		if (rdev->bdev->bd_dev == dev)
769 			return rdev;
770 
771 	return NULL;
772 }
773 
774 static struct md_personality *find_pers(int level, char *clevel)
775 {
776 	struct md_personality *pers;
777 	list_for_each_entry(pers, &pers_list, list) {
778 		if (level != LEVEL_NONE && pers->level == level)
779 			return pers;
780 		if (strcmp(pers->name, clevel)==0)
781 			return pers;
782 	}
783 	return NULL;
784 }
785 
786 /* return the offset of the super block in 512byte sectors */
787 static inline sector_t calc_dev_sboffset(struct md_rdev *rdev)
788 {
789 	sector_t num_sectors = i_size_read(rdev->bdev->bd_inode) / 512;
790 	return MD_NEW_SIZE_SECTORS(num_sectors);
791 }
792 
793 static int alloc_disk_sb(struct md_rdev * rdev)
794 {
795 	if (rdev->sb_page)
796 		MD_BUG();
797 
798 	rdev->sb_page = alloc_page(GFP_KERNEL);
799 	if (!rdev->sb_page) {
800 		printk(KERN_ALERT "md: out of memory.\n");
801 		return -ENOMEM;
802 	}
803 
804 	return 0;
805 }
806 
807 void md_rdev_clear(struct md_rdev *rdev)
808 {
809 	if (rdev->sb_page) {
810 		put_page(rdev->sb_page);
811 		rdev->sb_loaded = 0;
812 		rdev->sb_page = NULL;
813 		rdev->sb_start = 0;
814 		rdev->sectors = 0;
815 	}
816 	if (rdev->bb_page) {
817 		put_page(rdev->bb_page);
818 		rdev->bb_page = NULL;
819 	}
820 	kfree(rdev->badblocks.page);
821 	rdev->badblocks.page = NULL;
822 }
823 EXPORT_SYMBOL_GPL(md_rdev_clear);
824 
825 static void super_written(struct bio *bio, int error)
826 {
827 	struct md_rdev *rdev = bio->bi_private;
828 	struct mddev *mddev = rdev->mddev;
829 
830 	if (error || !test_bit(BIO_UPTODATE, &bio->bi_flags)) {
831 		printk("md: super_written gets error=%d, uptodate=%d\n",
832 		       error, test_bit(BIO_UPTODATE, &bio->bi_flags));
833 		WARN_ON(test_bit(BIO_UPTODATE, &bio->bi_flags));
834 		md_error(mddev, rdev);
835 	}
836 
837 	if (atomic_dec_and_test(&mddev->pending_writes))
838 		wake_up(&mddev->sb_wait);
839 	bio_put(bio);
840 }
841 
842 void md_super_write(struct mddev *mddev, struct md_rdev *rdev,
843 		   sector_t sector, int size, struct page *page)
844 {
845 	/* write first size bytes of page to sector of rdev
846 	 * Increment mddev->pending_writes before returning
847 	 * and decrement it on completion, waking up sb_wait
848 	 * if zero is reached.
849 	 * If an error occurred, call md_error
850 	 */
851 	struct bio *bio = bio_alloc_mddev(GFP_NOIO, 1, mddev);
852 
853 	bio->bi_bdev = rdev->meta_bdev ? rdev->meta_bdev : rdev->bdev;
854 	bio->bi_sector = sector;
855 	bio_add_page(bio, page, size, 0);
856 	bio->bi_private = rdev;
857 	bio->bi_end_io = super_written;
858 
859 	atomic_inc(&mddev->pending_writes);
860 	submit_bio(WRITE_FLUSH_FUA, bio);
861 }
862 
863 void md_super_wait(struct mddev *mddev)
864 {
865 	/* wait for all superblock writes that were scheduled to complete */
866 	DEFINE_WAIT(wq);
867 	for(;;) {
868 		prepare_to_wait(&mddev->sb_wait, &wq, TASK_UNINTERRUPTIBLE);
869 		if (atomic_read(&mddev->pending_writes)==0)
870 			break;
871 		schedule();
872 	}
873 	finish_wait(&mddev->sb_wait, &wq);
874 }
875 
876 static void bi_complete(struct bio *bio, int error)
877 {
878 	complete((struct completion*)bio->bi_private);
879 }
880 
881 int sync_page_io(struct md_rdev *rdev, sector_t sector, int size,
882 		 struct page *page, int rw, bool metadata_op)
883 {
884 	struct bio *bio = bio_alloc_mddev(GFP_NOIO, 1, rdev->mddev);
885 	struct completion event;
886 	int ret;
887 
888 	rw |= REQ_SYNC;
889 
890 	bio->bi_bdev = (metadata_op && rdev->meta_bdev) ?
891 		rdev->meta_bdev : rdev->bdev;
892 	if (metadata_op)
893 		bio->bi_sector = sector + rdev->sb_start;
894 	else if (rdev->mddev->reshape_position != MaxSector &&
895 		 (rdev->mddev->reshape_backwards ==
896 		  (sector >= rdev->mddev->reshape_position)))
897 		bio->bi_sector = sector + rdev->new_data_offset;
898 	else
899 		bio->bi_sector = sector + rdev->data_offset;
900 	bio_add_page(bio, page, size, 0);
901 	init_completion(&event);
902 	bio->bi_private = &event;
903 	bio->bi_end_io = bi_complete;
904 	submit_bio(rw, bio);
905 	wait_for_completion(&event);
906 
907 	ret = test_bit(BIO_UPTODATE, &bio->bi_flags);
908 	bio_put(bio);
909 	return ret;
910 }
911 EXPORT_SYMBOL_GPL(sync_page_io);
912 
913 static int read_disk_sb(struct md_rdev * rdev, int size)
914 {
915 	char b[BDEVNAME_SIZE];
916 	if (!rdev->sb_page) {
917 		MD_BUG();
918 		return -EINVAL;
919 	}
920 	if (rdev->sb_loaded)
921 		return 0;
922 
923 
924 	if (!sync_page_io(rdev, 0, size, rdev->sb_page, READ, true))
925 		goto fail;
926 	rdev->sb_loaded = 1;
927 	return 0;
928 
929 fail:
930 	printk(KERN_WARNING "md: disabled device %s, could not read superblock.\n",
931 		bdevname(rdev->bdev,b));
932 	return -EINVAL;
933 }
934 
935 static int uuid_equal(mdp_super_t *sb1, mdp_super_t *sb2)
936 {
937 	return 	sb1->set_uuid0 == sb2->set_uuid0 &&
938 		sb1->set_uuid1 == sb2->set_uuid1 &&
939 		sb1->set_uuid2 == sb2->set_uuid2 &&
940 		sb1->set_uuid3 == sb2->set_uuid3;
941 }
942 
943 static int sb_equal(mdp_super_t *sb1, mdp_super_t *sb2)
944 {
945 	int ret;
946 	mdp_super_t *tmp1, *tmp2;
947 
948 	tmp1 = kmalloc(sizeof(*tmp1),GFP_KERNEL);
949 	tmp2 = kmalloc(sizeof(*tmp2),GFP_KERNEL);
950 
951 	if (!tmp1 || !tmp2) {
952 		ret = 0;
953 		printk(KERN_INFO "md.c sb_equal(): failed to allocate memory!\n");
954 		goto abort;
955 	}
956 
957 	*tmp1 = *sb1;
958 	*tmp2 = *sb2;
959 
960 	/*
961 	 * nr_disks is not constant
962 	 */
963 	tmp1->nr_disks = 0;
964 	tmp2->nr_disks = 0;
965 
966 	ret = (memcmp(tmp1, tmp2, MD_SB_GENERIC_CONSTANT_WORDS * 4) == 0);
967 abort:
968 	kfree(tmp1);
969 	kfree(tmp2);
970 	return ret;
971 }
972 
973 
974 static u32 md_csum_fold(u32 csum)
975 {
976 	csum = (csum & 0xffff) + (csum >> 16);
977 	return (csum & 0xffff) + (csum >> 16);
978 }
979 
980 static unsigned int calc_sb_csum(mdp_super_t * sb)
981 {
982 	u64 newcsum = 0;
983 	u32 *sb32 = (u32*)sb;
984 	int i;
985 	unsigned int disk_csum, csum;
986 
987 	disk_csum = sb->sb_csum;
988 	sb->sb_csum = 0;
989 
990 	for (i = 0; i < MD_SB_BYTES/4 ; i++)
991 		newcsum += sb32[i];
992 	csum = (newcsum & 0xffffffff) + (newcsum>>32);
993 
994 
995 #ifdef CONFIG_ALPHA
996 	/* This used to use csum_partial, which was wrong for several
997 	 * reasons including that different results are returned on
998 	 * different architectures.  It isn't critical that we get exactly
999 	 * the same return value as before (we always csum_fold before
1000 	 * testing, and that removes any differences).  However as we
1001 	 * know that csum_partial always returned a 16bit value on
1002 	 * alphas, do a fold to maximise conformity to previous behaviour.
1003 	 */
1004 	sb->sb_csum = md_csum_fold(disk_csum);
1005 #else
1006 	sb->sb_csum = disk_csum;
1007 #endif
1008 	return csum;
1009 }
1010 
1011 
1012 /*
1013  * Handle superblock details.
1014  * We want to be able to handle multiple superblock formats
1015  * so we have a common interface to them all, and an array of
1016  * different handlers.
1017  * We rely on user-space to write the initial superblock, and support
1018  * reading and updating of superblocks.
1019  * Interface methods are:
1020  *   int load_super(struct md_rdev *dev, struct md_rdev *refdev, int minor_version)
1021  *      loads and validates a superblock on dev.
1022  *      if refdev != NULL, compare superblocks on both devices
1023  *    Return:
1024  *      0 - dev has a superblock that is compatible with refdev
1025  *      1 - dev has a superblock that is compatible and newer than refdev
1026  *          so dev should be used as the refdev in future
1027  *     -EINVAL superblock incompatible or invalid
1028  *     -othererror e.g. -EIO
1029  *
1030  *   int validate_super(struct mddev *mddev, struct md_rdev *dev)
1031  *      Verify that dev is acceptable into mddev.
1032  *       The first time, mddev->raid_disks will be 0, and data from
1033  *       dev should be merged in.  Subsequent calls check that dev
1034  *       is new enough.  Return 0 or -EINVAL
1035  *
1036  *   void sync_super(struct mddev *mddev, struct md_rdev *dev)
1037  *     Update the superblock for rdev with data in mddev
1038  *     This does not write to disc.
1039  *
1040  */
1041 
1042 struct super_type  {
1043 	char		    *name;
1044 	struct module	    *owner;
1045 	int		    (*load_super)(struct md_rdev *rdev,
1046 					  struct md_rdev *refdev,
1047 					  int minor_version);
1048 	int		    (*validate_super)(struct mddev *mddev,
1049 					      struct md_rdev *rdev);
1050 	void		    (*sync_super)(struct mddev *mddev,
1051 					  struct md_rdev *rdev);
1052 	unsigned long long  (*rdev_size_change)(struct md_rdev *rdev,
1053 						sector_t num_sectors);
1054 	int		    (*allow_new_offset)(struct md_rdev *rdev,
1055 						unsigned long long new_offset);
1056 };
1057 
1058 /*
1059  * Check that the given mddev has no bitmap.
1060  *
1061  * This function is called from the run method of all personalities that do not
1062  * support bitmaps. It prints an error message and returns non-zero if mddev
1063  * has a bitmap. Otherwise, it returns 0.
1064  *
1065  */
1066 int md_check_no_bitmap(struct mddev *mddev)
1067 {
1068 	if (!mddev->bitmap_info.file && !mddev->bitmap_info.offset)
1069 		return 0;
1070 	printk(KERN_ERR "%s: bitmaps are not supported for %s\n",
1071 		mdname(mddev), mddev->pers->name);
1072 	return 1;
1073 }
1074 EXPORT_SYMBOL(md_check_no_bitmap);
1075 
1076 /*
1077  * load_super for 0.90.0
1078  */
1079 static int super_90_load(struct md_rdev *rdev, struct md_rdev *refdev, int minor_version)
1080 {
1081 	char b[BDEVNAME_SIZE], b2[BDEVNAME_SIZE];
1082 	mdp_super_t *sb;
1083 	int ret;
1084 
1085 	/*
1086 	 * Calculate the position of the superblock (512byte sectors),
1087 	 * it's at the end of the disk.
1088 	 *
1089 	 * It also happens to be a multiple of 4Kb.
1090 	 */
1091 	rdev->sb_start = calc_dev_sboffset(rdev);
1092 
1093 	ret = read_disk_sb(rdev, MD_SB_BYTES);
1094 	if (ret) return ret;
1095 
1096 	ret = -EINVAL;
1097 
1098 	bdevname(rdev->bdev, b);
1099 	sb = page_address(rdev->sb_page);
1100 
1101 	if (sb->md_magic != MD_SB_MAGIC) {
1102 		printk(KERN_ERR "md: invalid raid superblock magic on %s\n",
1103 		       b);
1104 		goto abort;
1105 	}
1106 
1107 	if (sb->major_version != 0 ||
1108 	    sb->minor_version < 90 ||
1109 	    sb->minor_version > 91) {
1110 		printk(KERN_WARNING "Bad version number %d.%d on %s\n",
1111 			sb->major_version, sb->minor_version,
1112 			b);
1113 		goto abort;
1114 	}
1115 
1116 	if (sb->raid_disks <= 0)
1117 		goto abort;
1118 
1119 	if (md_csum_fold(calc_sb_csum(sb)) != md_csum_fold(sb->sb_csum)) {
1120 		printk(KERN_WARNING "md: invalid superblock checksum on %s\n",
1121 			b);
1122 		goto abort;
1123 	}
1124 
1125 	rdev->preferred_minor = sb->md_minor;
1126 	rdev->data_offset = 0;
1127 	rdev->new_data_offset = 0;
1128 	rdev->sb_size = MD_SB_BYTES;
1129 	rdev->badblocks.shift = -1;
1130 
1131 	if (sb->level == LEVEL_MULTIPATH)
1132 		rdev->desc_nr = -1;
1133 	else
1134 		rdev->desc_nr = sb->this_disk.number;
1135 
1136 	if (!refdev) {
1137 		ret = 1;
1138 	} else {
1139 		__u64 ev1, ev2;
1140 		mdp_super_t *refsb = page_address(refdev->sb_page);
1141 		if (!uuid_equal(refsb, sb)) {
1142 			printk(KERN_WARNING "md: %s has different UUID to %s\n",
1143 				b, bdevname(refdev->bdev,b2));
1144 			goto abort;
1145 		}
1146 		if (!sb_equal(refsb, sb)) {
1147 			printk(KERN_WARNING "md: %s has same UUID"
1148 			       " but different superblock to %s\n",
1149 			       b, bdevname(refdev->bdev, b2));
1150 			goto abort;
1151 		}
1152 		ev1 = md_event(sb);
1153 		ev2 = md_event(refsb);
1154 		if (ev1 > ev2)
1155 			ret = 1;
1156 		else
1157 			ret = 0;
1158 	}
1159 	rdev->sectors = rdev->sb_start;
1160 	/* Limit to 4TB as metadata cannot record more than that */
1161 	if (rdev->sectors >= (2ULL << 32))
1162 		rdev->sectors = (2ULL << 32) - 2;
1163 
1164 	if (rdev->sectors < ((sector_t)sb->size) * 2 && sb->level >= 1)
1165 		/* "this cannot possibly happen" ... */
1166 		ret = -EINVAL;
1167 
1168  abort:
1169 	return ret;
1170 }
1171 
1172 /*
1173  * validate_super for 0.90.0
1174  */
1175 static int super_90_validate(struct mddev *mddev, struct md_rdev *rdev)
1176 {
1177 	mdp_disk_t *desc;
1178 	mdp_super_t *sb = page_address(rdev->sb_page);
1179 	__u64 ev1 = md_event(sb);
1180 
1181 	rdev->raid_disk = -1;
1182 	clear_bit(Faulty, &rdev->flags);
1183 	clear_bit(In_sync, &rdev->flags);
1184 	clear_bit(WriteMostly, &rdev->flags);
1185 
1186 	if (mddev->raid_disks == 0) {
1187 		mddev->major_version = 0;
1188 		mddev->minor_version = sb->minor_version;
1189 		mddev->patch_version = sb->patch_version;
1190 		mddev->external = 0;
1191 		mddev->chunk_sectors = sb->chunk_size >> 9;
1192 		mddev->ctime = sb->ctime;
1193 		mddev->utime = sb->utime;
1194 		mddev->level = sb->level;
1195 		mddev->clevel[0] = 0;
1196 		mddev->layout = sb->layout;
1197 		mddev->raid_disks = sb->raid_disks;
1198 		mddev->dev_sectors = ((sector_t)sb->size) * 2;
1199 		mddev->events = ev1;
1200 		mddev->bitmap_info.offset = 0;
1201 		mddev->bitmap_info.space = 0;
1202 		/* bitmap can use 60 K after the 4K superblocks */
1203 		mddev->bitmap_info.default_offset = MD_SB_BYTES >> 9;
1204 		mddev->bitmap_info.default_space = 64*2 - (MD_SB_BYTES >> 9);
1205 		mddev->reshape_backwards = 0;
1206 
1207 		if (mddev->minor_version >= 91) {
1208 			mddev->reshape_position = sb->reshape_position;
1209 			mddev->delta_disks = sb->delta_disks;
1210 			mddev->new_level = sb->new_level;
1211 			mddev->new_layout = sb->new_layout;
1212 			mddev->new_chunk_sectors = sb->new_chunk >> 9;
1213 			if (mddev->delta_disks < 0)
1214 				mddev->reshape_backwards = 1;
1215 		} else {
1216 			mddev->reshape_position = MaxSector;
1217 			mddev->delta_disks = 0;
1218 			mddev->new_level = mddev->level;
1219 			mddev->new_layout = mddev->layout;
1220 			mddev->new_chunk_sectors = mddev->chunk_sectors;
1221 		}
1222 
1223 		if (sb->state & (1<<MD_SB_CLEAN))
1224 			mddev->recovery_cp = MaxSector;
1225 		else {
1226 			if (sb->events_hi == sb->cp_events_hi &&
1227 				sb->events_lo == sb->cp_events_lo) {
1228 				mddev->recovery_cp = sb->recovery_cp;
1229 			} else
1230 				mddev->recovery_cp = 0;
1231 		}
1232 
1233 		memcpy(mddev->uuid+0, &sb->set_uuid0, 4);
1234 		memcpy(mddev->uuid+4, &sb->set_uuid1, 4);
1235 		memcpy(mddev->uuid+8, &sb->set_uuid2, 4);
1236 		memcpy(mddev->uuid+12,&sb->set_uuid3, 4);
1237 
1238 		mddev->max_disks = MD_SB_DISKS;
1239 
1240 		if (sb->state & (1<<MD_SB_BITMAP_PRESENT) &&
1241 		    mddev->bitmap_info.file == NULL) {
1242 			mddev->bitmap_info.offset =
1243 				mddev->bitmap_info.default_offset;
1244 			mddev->bitmap_info.space =
1245 				mddev->bitmap_info.space;
1246 		}
1247 
1248 	} else if (mddev->pers == NULL) {
1249 		/* Insist on good event counter while assembling, except
1250 		 * for spares (which don't need an event count) */
1251 		++ev1;
1252 		if (sb->disks[rdev->desc_nr].state & (
1253 			    (1<<MD_DISK_SYNC) | (1 << MD_DISK_ACTIVE)))
1254 			if (ev1 < mddev->events)
1255 				return -EINVAL;
1256 	} else if (mddev->bitmap) {
1257 		/* if adding to array with a bitmap, then we can accept an
1258 		 * older device ... but not too old.
1259 		 */
1260 		if (ev1 < mddev->bitmap->events_cleared)
1261 			return 0;
1262 	} else {
1263 		if (ev1 < mddev->events)
1264 			/* just a hot-add of a new device, leave raid_disk at -1 */
1265 			return 0;
1266 	}
1267 
1268 	if (mddev->level != LEVEL_MULTIPATH) {
1269 		desc = sb->disks + rdev->desc_nr;
1270 
1271 		if (desc->state & (1<<MD_DISK_FAULTY))
1272 			set_bit(Faulty, &rdev->flags);
1273 		else if (desc->state & (1<<MD_DISK_SYNC) /* &&
1274 			    desc->raid_disk < mddev->raid_disks */) {
1275 			set_bit(In_sync, &rdev->flags);
1276 			rdev->raid_disk = desc->raid_disk;
1277 		} else if (desc->state & (1<<MD_DISK_ACTIVE)) {
1278 			/* active but not in sync implies recovery up to
1279 			 * reshape position.  We don't know exactly where
1280 			 * that is, so set to zero for now */
1281 			if (mddev->minor_version >= 91) {
1282 				rdev->recovery_offset = 0;
1283 				rdev->raid_disk = desc->raid_disk;
1284 			}
1285 		}
1286 		if (desc->state & (1<<MD_DISK_WRITEMOSTLY))
1287 			set_bit(WriteMostly, &rdev->flags);
1288 	} else /* MULTIPATH are always insync */
1289 		set_bit(In_sync, &rdev->flags);
1290 	return 0;
1291 }
1292 
1293 /*
1294  * sync_super for 0.90.0
1295  */
1296 static void super_90_sync(struct mddev *mddev, struct md_rdev *rdev)
1297 {
1298 	mdp_super_t *sb;
1299 	struct md_rdev *rdev2;
1300 	int next_spare = mddev->raid_disks;
1301 
1302 
1303 	/* make rdev->sb match mddev data..
1304 	 *
1305 	 * 1/ zero out disks
1306 	 * 2/ Add info for each disk, keeping track of highest desc_nr (next_spare);
1307 	 * 3/ any empty disks < next_spare become removed
1308 	 *
1309 	 * disks[0] gets initialised to REMOVED because
1310 	 * we cannot be sure from other fields if it has
1311 	 * been initialised or not.
1312 	 */
1313 	int i;
1314 	int active=0, working=0,failed=0,spare=0,nr_disks=0;
1315 
1316 	rdev->sb_size = MD_SB_BYTES;
1317 
1318 	sb = page_address(rdev->sb_page);
1319 
1320 	memset(sb, 0, sizeof(*sb));
1321 
1322 	sb->md_magic = MD_SB_MAGIC;
1323 	sb->major_version = mddev->major_version;
1324 	sb->patch_version = mddev->patch_version;
1325 	sb->gvalid_words  = 0; /* ignored */
1326 	memcpy(&sb->set_uuid0, mddev->uuid+0, 4);
1327 	memcpy(&sb->set_uuid1, mddev->uuid+4, 4);
1328 	memcpy(&sb->set_uuid2, mddev->uuid+8, 4);
1329 	memcpy(&sb->set_uuid3, mddev->uuid+12,4);
1330 
1331 	sb->ctime = mddev->ctime;
1332 	sb->level = mddev->level;
1333 	sb->size = mddev->dev_sectors / 2;
1334 	sb->raid_disks = mddev->raid_disks;
1335 	sb->md_minor = mddev->md_minor;
1336 	sb->not_persistent = 0;
1337 	sb->utime = mddev->utime;
1338 	sb->state = 0;
1339 	sb->events_hi = (mddev->events>>32);
1340 	sb->events_lo = (u32)mddev->events;
1341 
1342 	if (mddev->reshape_position == MaxSector)
1343 		sb->minor_version = 90;
1344 	else {
1345 		sb->minor_version = 91;
1346 		sb->reshape_position = mddev->reshape_position;
1347 		sb->new_level = mddev->new_level;
1348 		sb->delta_disks = mddev->delta_disks;
1349 		sb->new_layout = mddev->new_layout;
1350 		sb->new_chunk = mddev->new_chunk_sectors << 9;
1351 	}
1352 	mddev->minor_version = sb->minor_version;
1353 	if (mddev->in_sync)
1354 	{
1355 		sb->recovery_cp = mddev->recovery_cp;
1356 		sb->cp_events_hi = (mddev->events>>32);
1357 		sb->cp_events_lo = (u32)mddev->events;
1358 		if (mddev->recovery_cp == MaxSector)
1359 			sb->state = (1<< MD_SB_CLEAN);
1360 	} else
1361 		sb->recovery_cp = 0;
1362 
1363 	sb->layout = mddev->layout;
1364 	sb->chunk_size = mddev->chunk_sectors << 9;
1365 
1366 	if (mddev->bitmap && mddev->bitmap_info.file == NULL)
1367 		sb->state |= (1<<MD_SB_BITMAP_PRESENT);
1368 
1369 	sb->disks[0].state = (1<<MD_DISK_REMOVED);
1370 	rdev_for_each(rdev2, mddev) {
1371 		mdp_disk_t *d;
1372 		int desc_nr;
1373 		int is_active = test_bit(In_sync, &rdev2->flags);
1374 
1375 		if (rdev2->raid_disk >= 0 &&
1376 		    sb->minor_version >= 91)
1377 			/* we have nowhere to store the recovery_offset,
1378 			 * but if it is not below the reshape_position,
1379 			 * we can piggy-back on that.
1380 			 */
1381 			is_active = 1;
1382 		if (rdev2->raid_disk < 0 ||
1383 		    test_bit(Faulty, &rdev2->flags))
1384 			is_active = 0;
1385 		if (is_active)
1386 			desc_nr = rdev2->raid_disk;
1387 		else
1388 			desc_nr = next_spare++;
1389 		rdev2->desc_nr = desc_nr;
1390 		d = &sb->disks[rdev2->desc_nr];
1391 		nr_disks++;
1392 		d->number = rdev2->desc_nr;
1393 		d->major = MAJOR(rdev2->bdev->bd_dev);
1394 		d->minor = MINOR(rdev2->bdev->bd_dev);
1395 		if (is_active)
1396 			d->raid_disk = rdev2->raid_disk;
1397 		else
1398 			d->raid_disk = rdev2->desc_nr; /* compatibility */
1399 		if (test_bit(Faulty, &rdev2->flags))
1400 			d->state = (1<<MD_DISK_FAULTY);
1401 		else if (is_active) {
1402 			d->state = (1<<MD_DISK_ACTIVE);
1403 			if (test_bit(In_sync, &rdev2->flags))
1404 				d->state |= (1<<MD_DISK_SYNC);
1405 			active++;
1406 			working++;
1407 		} else {
1408 			d->state = 0;
1409 			spare++;
1410 			working++;
1411 		}
1412 		if (test_bit(WriteMostly, &rdev2->flags))
1413 			d->state |= (1<<MD_DISK_WRITEMOSTLY);
1414 	}
1415 	/* now set the "removed" and "faulty" bits on any missing devices */
1416 	for (i=0 ; i < mddev->raid_disks ; i++) {
1417 		mdp_disk_t *d = &sb->disks[i];
1418 		if (d->state == 0 && d->number == 0) {
1419 			d->number = i;
1420 			d->raid_disk = i;
1421 			d->state = (1<<MD_DISK_REMOVED);
1422 			d->state |= (1<<MD_DISK_FAULTY);
1423 			failed++;
1424 		}
1425 	}
1426 	sb->nr_disks = nr_disks;
1427 	sb->active_disks = active;
1428 	sb->working_disks = working;
1429 	sb->failed_disks = failed;
1430 	sb->spare_disks = spare;
1431 
1432 	sb->this_disk = sb->disks[rdev->desc_nr];
1433 	sb->sb_csum = calc_sb_csum(sb);
1434 }
1435 
1436 /*
1437  * rdev_size_change for 0.90.0
1438  */
1439 static unsigned long long
1440 super_90_rdev_size_change(struct md_rdev *rdev, sector_t num_sectors)
1441 {
1442 	if (num_sectors && num_sectors < rdev->mddev->dev_sectors)
1443 		return 0; /* component must fit device */
1444 	if (rdev->mddev->bitmap_info.offset)
1445 		return 0; /* can't move bitmap */
1446 	rdev->sb_start = calc_dev_sboffset(rdev);
1447 	if (!num_sectors || num_sectors > rdev->sb_start)
1448 		num_sectors = rdev->sb_start;
1449 	/* Limit to 4TB as metadata cannot record more than that.
1450 	 * 4TB == 2^32 KB, or 2*2^32 sectors.
1451 	 */
1452 	if (num_sectors >= (2ULL << 32))
1453 		num_sectors = (2ULL << 32) - 2;
1454 	md_super_write(rdev->mddev, rdev, rdev->sb_start, rdev->sb_size,
1455 		       rdev->sb_page);
1456 	md_super_wait(rdev->mddev);
1457 	return num_sectors;
1458 }
1459 
1460 static int
1461 super_90_allow_new_offset(struct md_rdev *rdev, unsigned long long new_offset)
1462 {
1463 	/* non-zero offset changes not possible with v0.90 */
1464 	return new_offset == 0;
1465 }
1466 
1467 /*
1468  * version 1 superblock
1469  */
1470 
1471 static __le32 calc_sb_1_csum(struct mdp_superblock_1 * sb)
1472 {
1473 	__le32 disk_csum;
1474 	u32 csum;
1475 	unsigned long long newcsum;
1476 	int size = 256 + le32_to_cpu(sb->max_dev)*2;
1477 	__le32 *isuper = (__le32*)sb;
1478 	int i;
1479 
1480 	disk_csum = sb->sb_csum;
1481 	sb->sb_csum = 0;
1482 	newcsum = 0;
1483 	for (i=0; size>=4; size -= 4 )
1484 		newcsum += le32_to_cpu(*isuper++);
1485 
1486 	if (size == 2)
1487 		newcsum += le16_to_cpu(*(__le16*) isuper);
1488 
1489 	csum = (newcsum & 0xffffffff) + (newcsum >> 32);
1490 	sb->sb_csum = disk_csum;
1491 	return cpu_to_le32(csum);
1492 }
1493 
1494 static int md_set_badblocks(struct badblocks *bb, sector_t s, int sectors,
1495 			    int acknowledged);
1496 static int super_1_load(struct md_rdev *rdev, struct md_rdev *refdev, int minor_version)
1497 {
1498 	struct mdp_superblock_1 *sb;
1499 	int ret;
1500 	sector_t sb_start;
1501 	sector_t sectors;
1502 	char b[BDEVNAME_SIZE], b2[BDEVNAME_SIZE];
1503 	int bmask;
1504 
1505 	/*
1506 	 * Calculate the position of the superblock in 512byte sectors.
1507 	 * It is always aligned to a 4K boundary and
1508 	 * depeding on minor_version, it can be:
1509 	 * 0: At least 8K, but less than 12K, from end of device
1510 	 * 1: At start of device
1511 	 * 2: 4K from start of device.
1512 	 */
1513 	switch(minor_version) {
1514 	case 0:
1515 		sb_start = i_size_read(rdev->bdev->bd_inode) >> 9;
1516 		sb_start -= 8*2;
1517 		sb_start &= ~(sector_t)(4*2-1);
1518 		break;
1519 	case 1:
1520 		sb_start = 0;
1521 		break;
1522 	case 2:
1523 		sb_start = 8;
1524 		break;
1525 	default:
1526 		return -EINVAL;
1527 	}
1528 	rdev->sb_start = sb_start;
1529 
1530 	/* superblock is rarely larger than 1K, but it can be larger,
1531 	 * and it is safe to read 4k, so we do that
1532 	 */
1533 	ret = read_disk_sb(rdev, 4096);
1534 	if (ret) return ret;
1535 
1536 
1537 	sb = page_address(rdev->sb_page);
1538 
1539 	if (sb->magic != cpu_to_le32(MD_SB_MAGIC) ||
1540 	    sb->major_version != cpu_to_le32(1) ||
1541 	    le32_to_cpu(sb->max_dev) > (4096-256)/2 ||
1542 	    le64_to_cpu(sb->super_offset) != rdev->sb_start ||
1543 	    (le32_to_cpu(sb->feature_map) & ~MD_FEATURE_ALL) != 0)
1544 		return -EINVAL;
1545 
1546 	if (calc_sb_1_csum(sb) != sb->sb_csum) {
1547 		printk("md: invalid superblock checksum on %s\n",
1548 			bdevname(rdev->bdev,b));
1549 		return -EINVAL;
1550 	}
1551 	if (le64_to_cpu(sb->data_size) < 10) {
1552 		printk("md: data_size too small on %s\n",
1553 		       bdevname(rdev->bdev,b));
1554 		return -EINVAL;
1555 	}
1556 	if (sb->pad0 ||
1557 	    sb->pad3[0] ||
1558 	    memcmp(sb->pad3, sb->pad3+1, sizeof(sb->pad3) - sizeof(sb->pad3[1])))
1559 		/* Some padding is non-zero, might be a new feature */
1560 		return -EINVAL;
1561 
1562 	rdev->preferred_minor = 0xffff;
1563 	rdev->data_offset = le64_to_cpu(sb->data_offset);
1564 	rdev->new_data_offset = rdev->data_offset;
1565 	if ((le32_to_cpu(sb->feature_map) & MD_FEATURE_RESHAPE_ACTIVE) &&
1566 	    (le32_to_cpu(sb->feature_map) & MD_FEATURE_NEW_OFFSET))
1567 		rdev->new_data_offset += (s32)le32_to_cpu(sb->new_offset);
1568 	atomic_set(&rdev->corrected_errors, le32_to_cpu(sb->cnt_corrected_read));
1569 
1570 	rdev->sb_size = le32_to_cpu(sb->max_dev) * 2 + 256;
1571 	bmask = queue_logical_block_size(rdev->bdev->bd_disk->queue)-1;
1572 	if (rdev->sb_size & bmask)
1573 		rdev->sb_size = (rdev->sb_size | bmask) + 1;
1574 
1575 	if (minor_version
1576 	    && rdev->data_offset < sb_start + (rdev->sb_size/512))
1577 		return -EINVAL;
1578 	if (minor_version
1579 	    && rdev->new_data_offset < sb_start + (rdev->sb_size/512))
1580 		return -EINVAL;
1581 
1582 	if (sb->level == cpu_to_le32(LEVEL_MULTIPATH))
1583 		rdev->desc_nr = -1;
1584 	else
1585 		rdev->desc_nr = le32_to_cpu(sb->dev_number);
1586 
1587 	if (!rdev->bb_page) {
1588 		rdev->bb_page = alloc_page(GFP_KERNEL);
1589 		if (!rdev->bb_page)
1590 			return -ENOMEM;
1591 	}
1592 	if ((le32_to_cpu(sb->feature_map) & MD_FEATURE_BAD_BLOCKS) &&
1593 	    rdev->badblocks.count == 0) {
1594 		/* need to load the bad block list.
1595 		 * Currently we limit it to one page.
1596 		 */
1597 		s32 offset;
1598 		sector_t bb_sector;
1599 		u64 *bbp;
1600 		int i;
1601 		int sectors = le16_to_cpu(sb->bblog_size);
1602 		if (sectors > (PAGE_SIZE / 512))
1603 			return -EINVAL;
1604 		offset = le32_to_cpu(sb->bblog_offset);
1605 		if (offset == 0)
1606 			return -EINVAL;
1607 		bb_sector = (long long)offset;
1608 		if (!sync_page_io(rdev, bb_sector, sectors << 9,
1609 				  rdev->bb_page, READ, true))
1610 			return -EIO;
1611 		bbp = (u64 *)page_address(rdev->bb_page);
1612 		rdev->badblocks.shift = sb->bblog_shift;
1613 		for (i = 0 ; i < (sectors << (9-3)) ; i++, bbp++) {
1614 			u64 bb = le64_to_cpu(*bbp);
1615 			int count = bb & (0x3ff);
1616 			u64 sector = bb >> 10;
1617 			sector <<= sb->bblog_shift;
1618 			count <<= sb->bblog_shift;
1619 			if (bb + 1 == 0)
1620 				break;
1621 			if (md_set_badblocks(&rdev->badblocks,
1622 					     sector, count, 1) == 0)
1623 				return -EINVAL;
1624 		}
1625 	} else if (sb->bblog_offset == 0)
1626 		rdev->badblocks.shift = -1;
1627 
1628 	if (!refdev) {
1629 		ret = 1;
1630 	} else {
1631 		__u64 ev1, ev2;
1632 		struct mdp_superblock_1 *refsb = page_address(refdev->sb_page);
1633 
1634 		if (memcmp(sb->set_uuid, refsb->set_uuid, 16) != 0 ||
1635 		    sb->level != refsb->level ||
1636 		    sb->layout != refsb->layout ||
1637 		    sb->chunksize != refsb->chunksize) {
1638 			printk(KERN_WARNING "md: %s has strangely different"
1639 				" superblock to %s\n",
1640 				bdevname(rdev->bdev,b),
1641 				bdevname(refdev->bdev,b2));
1642 			return -EINVAL;
1643 		}
1644 		ev1 = le64_to_cpu(sb->events);
1645 		ev2 = le64_to_cpu(refsb->events);
1646 
1647 		if (ev1 > ev2)
1648 			ret = 1;
1649 		else
1650 			ret = 0;
1651 	}
1652 	if (minor_version) {
1653 		sectors = (i_size_read(rdev->bdev->bd_inode) >> 9);
1654 		sectors -= rdev->data_offset;
1655 	} else
1656 		sectors = rdev->sb_start;
1657 	if (sectors < le64_to_cpu(sb->data_size))
1658 		return -EINVAL;
1659 	rdev->sectors = le64_to_cpu(sb->data_size);
1660 	return ret;
1661 }
1662 
1663 static int super_1_validate(struct mddev *mddev, struct md_rdev *rdev)
1664 {
1665 	struct mdp_superblock_1 *sb = page_address(rdev->sb_page);
1666 	__u64 ev1 = le64_to_cpu(sb->events);
1667 
1668 	rdev->raid_disk = -1;
1669 	clear_bit(Faulty, &rdev->flags);
1670 	clear_bit(In_sync, &rdev->flags);
1671 	clear_bit(WriteMostly, &rdev->flags);
1672 
1673 	if (mddev->raid_disks == 0) {
1674 		mddev->major_version = 1;
1675 		mddev->patch_version = 0;
1676 		mddev->external = 0;
1677 		mddev->chunk_sectors = le32_to_cpu(sb->chunksize);
1678 		mddev->ctime = le64_to_cpu(sb->ctime) & ((1ULL << 32)-1);
1679 		mddev->utime = le64_to_cpu(sb->utime) & ((1ULL << 32)-1);
1680 		mddev->level = le32_to_cpu(sb->level);
1681 		mddev->clevel[0] = 0;
1682 		mddev->layout = le32_to_cpu(sb->layout);
1683 		mddev->raid_disks = le32_to_cpu(sb->raid_disks);
1684 		mddev->dev_sectors = le64_to_cpu(sb->size);
1685 		mddev->events = ev1;
1686 		mddev->bitmap_info.offset = 0;
1687 		mddev->bitmap_info.space = 0;
1688 		/* Default location for bitmap is 1K after superblock
1689 		 * using 3K - total of 4K
1690 		 */
1691 		mddev->bitmap_info.default_offset = 1024 >> 9;
1692 		mddev->bitmap_info.default_space = (4096-1024) >> 9;
1693 		mddev->reshape_backwards = 0;
1694 
1695 		mddev->recovery_cp = le64_to_cpu(sb->resync_offset);
1696 		memcpy(mddev->uuid, sb->set_uuid, 16);
1697 
1698 		mddev->max_disks =  (4096-256)/2;
1699 
1700 		if ((le32_to_cpu(sb->feature_map) & MD_FEATURE_BITMAP_OFFSET) &&
1701 		    mddev->bitmap_info.file == NULL) {
1702 			mddev->bitmap_info.offset =
1703 				(__s32)le32_to_cpu(sb->bitmap_offset);
1704 			/* Metadata doesn't record how much space is available.
1705 			 * For 1.0, we assume we can use up to the superblock
1706 			 * if before, else to 4K beyond superblock.
1707 			 * For others, assume no change is possible.
1708 			 */
1709 			if (mddev->minor_version > 0)
1710 				mddev->bitmap_info.space = 0;
1711 			else if (mddev->bitmap_info.offset > 0)
1712 				mddev->bitmap_info.space =
1713 					8 - mddev->bitmap_info.offset;
1714 			else
1715 				mddev->bitmap_info.space =
1716 					-mddev->bitmap_info.offset;
1717 		}
1718 
1719 		if ((le32_to_cpu(sb->feature_map) & MD_FEATURE_RESHAPE_ACTIVE)) {
1720 			mddev->reshape_position = le64_to_cpu(sb->reshape_position);
1721 			mddev->delta_disks = le32_to_cpu(sb->delta_disks);
1722 			mddev->new_level = le32_to_cpu(sb->new_level);
1723 			mddev->new_layout = le32_to_cpu(sb->new_layout);
1724 			mddev->new_chunk_sectors = le32_to_cpu(sb->new_chunk);
1725 			if (mddev->delta_disks < 0 ||
1726 			    (mddev->delta_disks == 0 &&
1727 			     (le32_to_cpu(sb->feature_map)
1728 			      & MD_FEATURE_RESHAPE_BACKWARDS)))
1729 				mddev->reshape_backwards = 1;
1730 		} else {
1731 			mddev->reshape_position = MaxSector;
1732 			mddev->delta_disks = 0;
1733 			mddev->new_level = mddev->level;
1734 			mddev->new_layout = mddev->layout;
1735 			mddev->new_chunk_sectors = mddev->chunk_sectors;
1736 		}
1737 
1738 	} else if (mddev->pers == NULL) {
1739 		/* Insist of good event counter while assembling, except for
1740 		 * spares (which don't need an event count) */
1741 		++ev1;
1742 		if (rdev->desc_nr >= 0 &&
1743 		    rdev->desc_nr < le32_to_cpu(sb->max_dev) &&
1744 		    le16_to_cpu(sb->dev_roles[rdev->desc_nr]) < 0xfffe)
1745 			if (ev1 < mddev->events)
1746 				return -EINVAL;
1747 	} else if (mddev->bitmap) {
1748 		/* If adding to array with a bitmap, then we can accept an
1749 		 * older device, but not too old.
1750 		 */
1751 		if (ev1 < mddev->bitmap->events_cleared)
1752 			return 0;
1753 	} else {
1754 		if (ev1 < mddev->events)
1755 			/* just a hot-add of a new device, leave raid_disk at -1 */
1756 			return 0;
1757 	}
1758 	if (mddev->level != LEVEL_MULTIPATH) {
1759 		int role;
1760 		if (rdev->desc_nr < 0 ||
1761 		    rdev->desc_nr >= le32_to_cpu(sb->max_dev)) {
1762 			role = 0xffff;
1763 			rdev->desc_nr = -1;
1764 		} else
1765 			role = le16_to_cpu(sb->dev_roles[rdev->desc_nr]);
1766 		switch(role) {
1767 		case 0xffff: /* spare */
1768 			break;
1769 		case 0xfffe: /* faulty */
1770 			set_bit(Faulty, &rdev->flags);
1771 			break;
1772 		default:
1773 			if ((le32_to_cpu(sb->feature_map) &
1774 			     MD_FEATURE_RECOVERY_OFFSET))
1775 				rdev->recovery_offset = le64_to_cpu(sb->recovery_offset);
1776 			else
1777 				set_bit(In_sync, &rdev->flags);
1778 			rdev->raid_disk = role;
1779 			break;
1780 		}
1781 		if (sb->devflags & WriteMostly1)
1782 			set_bit(WriteMostly, &rdev->flags);
1783 		if (le32_to_cpu(sb->feature_map) & MD_FEATURE_REPLACEMENT)
1784 			set_bit(Replacement, &rdev->flags);
1785 	} else /* MULTIPATH are always insync */
1786 		set_bit(In_sync, &rdev->flags);
1787 
1788 	return 0;
1789 }
1790 
1791 static void super_1_sync(struct mddev *mddev, struct md_rdev *rdev)
1792 {
1793 	struct mdp_superblock_1 *sb;
1794 	struct md_rdev *rdev2;
1795 	int max_dev, i;
1796 	/* make rdev->sb match mddev and rdev data. */
1797 
1798 	sb = page_address(rdev->sb_page);
1799 
1800 	sb->feature_map = 0;
1801 	sb->pad0 = 0;
1802 	sb->recovery_offset = cpu_to_le64(0);
1803 	memset(sb->pad3, 0, sizeof(sb->pad3));
1804 
1805 	sb->utime = cpu_to_le64((__u64)mddev->utime);
1806 	sb->events = cpu_to_le64(mddev->events);
1807 	if (mddev->in_sync)
1808 		sb->resync_offset = cpu_to_le64(mddev->recovery_cp);
1809 	else
1810 		sb->resync_offset = cpu_to_le64(0);
1811 
1812 	sb->cnt_corrected_read = cpu_to_le32(atomic_read(&rdev->corrected_errors));
1813 
1814 	sb->raid_disks = cpu_to_le32(mddev->raid_disks);
1815 	sb->size = cpu_to_le64(mddev->dev_sectors);
1816 	sb->chunksize = cpu_to_le32(mddev->chunk_sectors);
1817 	sb->level = cpu_to_le32(mddev->level);
1818 	sb->layout = cpu_to_le32(mddev->layout);
1819 
1820 	if (test_bit(WriteMostly, &rdev->flags))
1821 		sb->devflags |= WriteMostly1;
1822 	else
1823 		sb->devflags &= ~WriteMostly1;
1824 	sb->data_offset = cpu_to_le64(rdev->data_offset);
1825 	sb->data_size = cpu_to_le64(rdev->sectors);
1826 
1827 	if (mddev->bitmap && mddev->bitmap_info.file == NULL) {
1828 		sb->bitmap_offset = cpu_to_le32((__u32)mddev->bitmap_info.offset);
1829 		sb->feature_map = cpu_to_le32(MD_FEATURE_BITMAP_OFFSET);
1830 	}
1831 
1832 	if (rdev->raid_disk >= 0 &&
1833 	    !test_bit(In_sync, &rdev->flags)) {
1834 		sb->feature_map |=
1835 			cpu_to_le32(MD_FEATURE_RECOVERY_OFFSET);
1836 		sb->recovery_offset =
1837 			cpu_to_le64(rdev->recovery_offset);
1838 	}
1839 	if (test_bit(Replacement, &rdev->flags))
1840 		sb->feature_map |=
1841 			cpu_to_le32(MD_FEATURE_REPLACEMENT);
1842 
1843 	if (mddev->reshape_position != MaxSector) {
1844 		sb->feature_map |= cpu_to_le32(MD_FEATURE_RESHAPE_ACTIVE);
1845 		sb->reshape_position = cpu_to_le64(mddev->reshape_position);
1846 		sb->new_layout = cpu_to_le32(mddev->new_layout);
1847 		sb->delta_disks = cpu_to_le32(mddev->delta_disks);
1848 		sb->new_level = cpu_to_le32(mddev->new_level);
1849 		sb->new_chunk = cpu_to_le32(mddev->new_chunk_sectors);
1850 		if (mddev->delta_disks == 0 &&
1851 		    mddev->reshape_backwards)
1852 			sb->feature_map
1853 				|= cpu_to_le32(MD_FEATURE_RESHAPE_BACKWARDS);
1854 		if (rdev->new_data_offset != rdev->data_offset) {
1855 			sb->feature_map
1856 				|= cpu_to_le32(MD_FEATURE_NEW_OFFSET);
1857 			sb->new_offset = cpu_to_le32((__u32)(rdev->new_data_offset
1858 							     - rdev->data_offset));
1859 		}
1860 	}
1861 
1862 	if (rdev->badblocks.count == 0)
1863 		/* Nothing to do for bad blocks*/ ;
1864 	else if (sb->bblog_offset == 0)
1865 		/* Cannot record bad blocks on this device */
1866 		md_error(mddev, rdev);
1867 	else {
1868 		struct badblocks *bb = &rdev->badblocks;
1869 		u64 *bbp = (u64 *)page_address(rdev->bb_page);
1870 		u64 *p = bb->page;
1871 		sb->feature_map |= cpu_to_le32(MD_FEATURE_BAD_BLOCKS);
1872 		if (bb->changed) {
1873 			unsigned seq;
1874 
1875 retry:
1876 			seq = read_seqbegin(&bb->lock);
1877 
1878 			memset(bbp, 0xff, PAGE_SIZE);
1879 
1880 			for (i = 0 ; i < bb->count ; i++) {
1881 				u64 internal_bb = *p++;
1882 				u64 store_bb = ((BB_OFFSET(internal_bb) << 10)
1883 						| BB_LEN(internal_bb));
1884 				*bbp++ = cpu_to_le64(store_bb);
1885 			}
1886 			bb->changed = 0;
1887 			if (read_seqretry(&bb->lock, seq))
1888 				goto retry;
1889 
1890 			bb->sector = (rdev->sb_start +
1891 				      (int)le32_to_cpu(sb->bblog_offset));
1892 			bb->size = le16_to_cpu(sb->bblog_size);
1893 		}
1894 	}
1895 
1896 	max_dev = 0;
1897 	rdev_for_each(rdev2, mddev)
1898 		if (rdev2->desc_nr+1 > max_dev)
1899 			max_dev = rdev2->desc_nr+1;
1900 
1901 	if (max_dev > le32_to_cpu(sb->max_dev)) {
1902 		int bmask;
1903 		sb->max_dev = cpu_to_le32(max_dev);
1904 		rdev->sb_size = max_dev * 2 + 256;
1905 		bmask = queue_logical_block_size(rdev->bdev->bd_disk->queue)-1;
1906 		if (rdev->sb_size & bmask)
1907 			rdev->sb_size = (rdev->sb_size | bmask) + 1;
1908 	} else
1909 		max_dev = le32_to_cpu(sb->max_dev);
1910 
1911 	for (i=0; i<max_dev;i++)
1912 		sb->dev_roles[i] = cpu_to_le16(0xfffe);
1913 
1914 	rdev_for_each(rdev2, mddev) {
1915 		i = rdev2->desc_nr;
1916 		if (test_bit(Faulty, &rdev2->flags))
1917 			sb->dev_roles[i] = cpu_to_le16(0xfffe);
1918 		else if (test_bit(In_sync, &rdev2->flags))
1919 			sb->dev_roles[i] = cpu_to_le16(rdev2->raid_disk);
1920 		else if (rdev2->raid_disk >= 0)
1921 			sb->dev_roles[i] = cpu_to_le16(rdev2->raid_disk);
1922 		else
1923 			sb->dev_roles[i] = cpu_to_le16(0xffff);
1924 	}
1925 
1926 	sb->sb_csum = calc_sb_1_csum(sb);
1927 }
1928 
1929 static unsigned long long
1930 super_1_rdev_size_change(struct md_rdev *rdev, sector_t num_sectors)
1931 {
1932 	struct mdp_superblock_1 *sb;
1933 	sector_t max_sectors;
1934 	if (num_sectors && num_sectors < rdev->mddev->dev_sectors)
1935 		return 0; /* component must fit device */
1936 	if (rdev->data_offset != rdev->new_data_offset)
1937 		return 0; /* too confusing */
1938 	if (rdev->sb_start < rdev->data_offset) {
1939 		/* minor versions 1 and 2; superblock before data */
1940 		max_sectors = i_size_read(rdev->bdev->bd_inode) >> 9;
1941 		max_sectors -= rdev->data_offset;
1942 		if (!num_sectors || num_sectors > max_sectors)
1943 			num_sectors = max_sectors;
1944 	} else if (rdev->mddev->bitmap_info.offset) {
1945 		/* minor version 0 with bitmap we can't move */
1946 		return 0;
1947 	} else {
1948 		/* minor version 0; superblock after data */
1949 		sector_t sb_start;
1950 		sb_start = (i_size_read(rdev->bdev->bd_inode) >> 9) - 8*2;
1951 		sb_start &= ~(sector_t)(4*2 - 1);
1952 		max_sectors = rdev->sectors + sb_start - rdev->sb_start;
1953 		if (!num_sectors || num_sectors > max_sectors)
1954 			num_sectors = max_sectors;
1955 		rdev->sb_start = sb_start;
1956 	}
1957 	sb = page_address(rdev->sb_page);
1958 	sb->data_size = cpu_to_le64(num_sectors);
1959 	sb->super_offset = rdev->sb_start;
1960 	sb->sb_csum = calc_sb_1_csum(sb);
1961 	md_super_write(rdev->mddev, rdev, rdev->sb_start, rdev->sb_size,
1962 		       rdev->sb_page);
1963 	md_super_wait(rdev->mddev);
1964 	return num_sectors;
1965 
1966 }
1967 
1968 static int
1969 super_1_allow_new_offset(struct md_rdev *rdev,
1970 			 unsigned long long new_offset)
1971 {
1972 	/* All necessary checks on new >= old have been done */
1973 	struct bitmap *bitmap;
1974 	if (new_offset >= rdev->data_offset)
1975 		return 1;
1976 
1977 	/* with 1.0 metadata, there is no metadata to tread on
1978 	 * so we can always move back */
1979 	if (rdev->mddev->minor_version == 0)
1980 		return 1;
1981 
1982 	/* otherwise we must be sure not to step on
1983 	 * any metadata, so stay:
1984 	 * 36K beyond start of superblock
1985 	 * beyond end of badblocks
1986 	 * beyond write-intent bitmap
1987 	 */
1988 	if (rdev->sb_start + (32+4)*2 > new_offset)
1989 		return 0;
1990 	bitmap = rdev->mddev->bitmap;
1991 	if (bitmap && !rdev->mddev->bitmap_info.file &&
1992 	    rdev->sb_start + rdev->mddev->bitmap_info.offset +
1993 	    bitmap->storage.file_pages * (PAGE_SIZE>>9) > new_offset)
1994 		return 0;
1995 	if (rdev->badblocks.sector + rdev->badblocks.size > new_offset)
1996 		return 0;
1997 
1998 	return 1;
1999 }
2000 
2001 static struct super_type super_types[] = {
2002 	[0] = {
2003 		.name	= "0.90.0",
2004 		.owner	= THIS_MODULE,
2005 		.load_super	    = super_90_load,
2006 		.validate_super	    = super_90_validate,
2007 		.sync_super	    = super_90_sync,
2008 		.rdev_size_change   = super_90_rdev_size_change,
2009 		.allow_new_offset   = super_90_allow_new_offset,
2010 	},
2011 	[1] = {
2012 		.name	= "md-1",
2013 		.owner	= THIS_MODULE,
2014 		.load_super	    = super_1_load,
2015 		.validate_super	    = super_1_validate,
2016 		.sync_super	    = super_1_sync,
2017 		.rdev_size_change   = super_1_rdev_size_change,
2018 		.allow_new_offset   = super_1_allow_new_offset,
2019 	},
2020 };
2021 
2022 static void sync_super(struct mddev *mddev, struct md_rdev *rdev)
2023 {
2024 	if (mddev->sync_super) {
2025 		mddev->sync_super(mddev, rdev);
2026 		return;
2027 	}
2028 
2029 	BUG_ON(mddev->major_version >= ARRAY_SIZE(super_types));
2030 
2031 	super_types[mddev->major_version].sync_super(mddev, rdev);
2032 }
2033 
2034 static int match_mddev_units(struct mddev *mddev1, struct mddev *mddev2)
2035 {
2036 	struct md_rdev *rdev, *rdev2;
2037 
2038 	rcu_read_lock();
2039 	rdev_for_each_rcu(rdev, mddev1)
2040 		rdev_for_each_rcu(rdev2, mddev2)
2041 			if (rdev->bdev->bd_contains ==
2042 			    rdev2->bdev->bd_contains) {
2043 				rcu_read_unlock();
2044 				return 1;
2045 			}
2046 	rcu_read_unlock();
2047 	return 0;
2048 }
2049 
2050 static LIST_HEAD(pending_raid_disks);
2051 
2052 /*
2053  * Try to register data integrity profile for an mddev
2054  *
2055  * This is called when an array is started and after a disk has been kicked
2056  * from the array. It only succeeds if all working and active component devices
2057  * are integrity capable with matching profiles.
2058  */
2059 int md_integrity_register(struct mddev *mddev)
2060 {
2061 	struct md_rdev *rdev, *reference = NULL;
2062 
2063 	if (list_empty(&mddev->disks))
2064 		return 0; /* nothing to do */
2065 	if (!mddev->gendisk || blk_get_integrity(mddev->gendisk))
2066 		return 0; /* shouldn't register, or already is */
2067 	rdev_for_each(rdev, mddev) {
2068 		/* skip spares and non-functional disks */
2069 		if (test_bit(Faulty, &rdev->flags))
2070 			continue;
2071 		if (rdev->raid_disk < 0)
2072 			continue;
2073 		if (!reference) {
2074 			/* Use the first rdev as the reference */
2075 			reference = rdev;
2076 			continue;
2077 		}
2078 		/* does this rdev's profile match the reference profile? */
2079 		if (blk_integrity_compare(reference->bdev->bd_disk,
2080 				rdev->bdev->bd_disk) < 0)
2081 			return -EINVAL;
2082 	}
2083 	if (!reference || !bdev_get_integrity(reference->bdev))
2084 		return 0;
2085 	/*
2086 	 * All component devices are integrity capable and have matching
2087 	 * profiles, register the common profile for the md device.
2088 	 */
2089 	if (blk_integrity_register(mddev->gendisk,
2090 			bdev_get_integrity(reference->bdev)) != 0) {
2091 		printk(KERN_ERR "md: failed to register integrity for %s\n",
2092 			mdname(mddev));
2093 		return -EINVAL;
2094 	}
2095 	printk(KERN_NOTICE "md: data integrity enabled on %s\n", mdname(mddev));
2096 	if (bioset_integrity_create(mddev->bio_set, BIO_POOL_SIZE)) {
2097 		printk(KERN_ERR "md: failed to create integrity pool for %s\n",
2098 		       mdname(mddev));
2099 		return -EINVAL;
2100 	}
2101 	return 0;
2102 }
2103 EXPORT_SYMBOL(md_integrity_register);
2104 
2105 /* Disable data integrity if non-capable/non-matching disk is being added */
2106 void md_integrity_add_rdev(struct md_rdev *rdev, struct mddev *mddev)
2107 {
2108 	struct blk_integrity *bi_rdev = bdev_get_integrity(rdev->bdev);
2109 	struct blk_integrity *bi_mddev = blk_get_integrity(mddev->gendisk);
2110 
2111 	if (!bi_mddev) /* nothing to do */
2112 		return;
2113 	if (rdev->raid_disk < 0) /* skip spares */
2114 		return;
2115 	if (bi_rdev && blk_integrity_compare(mddev->gendisk,
2116 					     rdev->bdev->bd_disk) >= 0)
2117 		return;
2118 	printk(KERN_NOTICE "disabling data integrity on %s\n", mdname(mddev));
2119 	blk_integrity_unregister(mddev->gendisk);
2120 }
2121 EXPORT_SYMBOL(md_integrity_add_rdev);
2122 
2123 static int bind_rdev_to_array(struct md_rdev * rdev, struct mddev * mddev)
2124 {
2125 	char b[BDEVNAME_SIZE];
2126 	struct kobject *ko;
2127 	char *s;
2128 	int err;
2129 
2130 	if (rdev->mddev) {
2131 		MD_BUG();
2132 		return -EINVAL;
2133 	}
2134 
2135 	/* prevent duplicates */
2136 	if (find_rdev(mddev, rdev->bdev->bd_dev))
2137 		return -EEXIST;
2138 
2139 	/* make sure rdev->sectors exceeds mddev->dev_sectors */
2140 	if (rdev->sectors && (mddev->dev_sectors == 0 ||
2141 			rdev->sectors < mddev->dev_sectors)) {
2142 		if (mddev->pers) {
2143 			/* Cannot change size, so fail
2144 			 * If mddev->level <= 0, then we don't care
2145 			 * about aligning sizes (e.g. linear)
2146 			 */
2147 			if (mddev->level > 0)
2148 				return -ENOSPC;
2149 		} else
2150 			mddev->dev_sectors = rdev->sectors;
2151 	}
2152 
2153 	/* Verify rdev->desc_nr is unique.
2154 	 * If it is -1, assign a free number, else
2155 	 * check number is not in use
2156 	 */
2157 	if (rdev->desc_nr < 0) {
2158 		int choice = 0;
2159 		if (mddev->pers) choice = mddev->raid_disks;
2160 		while (find_rdev_nr(mddev, choice))
2161 			choice++;
2162 		rdev->desc_nr = choice;
2163 	} else {
2164 		if (find_rdev_nr(mddev, rdev->desc_nr))
2165 			return -EBUSY;
2166 	}
2167 	if (mddev->max_disks && rdev->desc_nr >= mddev->max_disks) {
2168 		printk(KERN_WARNING "md: %s: array is limited to %d devices\n",
2169 		       mdname(mddev), mddev->max_disks);
2170 		return -EBUSY;
2171 	}
2172 	bdevname(rdev->bdev,b);
2173 	while ( (s=strchr(b, '/')) != NULL)
2174 		*s = '!';
2175 
2176 	rdev->mddev = mddev;
2177 	printk(KERN_INFO "md: bind<%s>\n", b);
2178 
2179 	if ((err = kobject_add(&rdev->kobj, &mddev->kobj, "dev-%s", b)))
2180 		goto fail;
2181 
2182 	ko = &part_to_dev(rdev->bdev->bd_part)->kobj;
2183 	if (sysfs_create_link(&rdev->kobj, ko, "block"))
2184 		/* failure here is OK */;
2185 	rdev->sysfs_state = sysfs_get_dirent_safe(rdev->kobj.sd, "state");
2186 
2187 	list_add_rcu(&rdev->same_set, &mddev->disks);
2188 	bd_link_disk_holder(rdev->bdev, mddev->gendisk);
2189 
2190 	/* May as well allow recovery to be retried once */
2191 	mddev->recovery_disabled++;
2192 
2193 	return 0;
2194 
2195  fail:
2196 	printk(KERN_WARNING "md: failed to register dev-%s for %s\n",
2197 	       b, mdname(mddev));
2198 	return err;
2199 }
2200 
2201 static void md_delayed_delete(struct work_struct *ws)
2202 {
2203 	struct md_rdev *rdev = container_of(ws, struct md_rdev, del_work);
2204 	kobject_del(&rdev->kobj);
2205 	kobject_put(&rdev->kobj);
2206 }
2207 
2208 static void unbind_rdev_from_array(struct md_rdev * rdev)
2209 {
2210 	char b[BDEVNAME_SIZE];
2211 	if (!rdev->mddev) {
2212 		MD_BUG();
2213 		return;
2214 	}
2215 	bd_unlink_disk_holder(rdev->bdev, rdev->mddev->gendisk);
2216 	list_del_rcu(&rdev->same_set);
2217 	printk(KERN_INFO "md: unbind<%s>\n", bdevname(rdev->bdev,b));
2218 	rdev->mddev = NULL;
2219 	sysfs_remove_link(&rdev->kobj, "block");
2220 	sysfs_put(rdev->sysfs_state);
2221 	rdev->sysfs_state = NULL;
2222 	rdev->badblocks.count = 0;
2223 	/* We need to delay this, otherwise we can deadlock when
2224 	 * writing to 'remove' to "dev/state".  We also need
2225 	 * to delay it due to rcu usage.
2226 	 */
2227 	synchronize_rcu();
2228 	INIT_WORK(&rdev->del_work, md_delayed_delete);
2229 	kobject_get(&rdev->kobj);
2230 	queue_work(md_misc_wq, &rdev->del_work);
2231 }
2232 
2233 /*
2234  * prevent the device from being mounted, repartitioned or
2235  * otherwise reused by a RAID array (or any other kernel
2236  * subsystem), by bd_claiming the device.
2237  */
2238 static int lock_rdev(struct md_rdev *rdev, dev_t dev, int shared)
2239 {
2240 	int err = 0;
2241 	struct block_device *bdev;
2242 	char b[BDEVNAME_SIZE];
2243 
2244 	bdev = blkdev_get_by_dev(dev, FMODE_READ|FMODE_WRITE|FMODE_EXCL,
2245 				 shared ? (struct md_rdev *)lock_rdev : rdev);
2246 	if (IS_ERR(bdev)) {
2247 		printk(KERN_ERR "md: could not open %s.\n",
2248 			__bdevname(dev, b));
2249 		return PTR_ERR(bdev);
2250 	}
2251 	rdev->bdev = bdev;
2252 	return err;
2253 }
2254 
2255 static void unlock_rdev(struct md_rdev *rdev)
2256 {
2257 	struct block_device *bdev = rdev->bdev;
2258 	rdev->bdev = NULL;
2259 	if (!bdev)
2260 		MD_BUG();
2261 	blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
2262 }
2263 
2264 void md_autodetect_dev(dev_t dev);
2265 
2266 static void export_rdev(struct md_rdev * rdev)
2267 {
2268 	char b[BDEVNAME_SIZE];
2269 	printk(KERN_INFO "md: export_rdev(%s)\n",
2270 		bdevname(rdev->bdev,b));
2271 	if (rdev->mddev)
2272 		MD_BUG();
2273 	md_rdev_clear(rdev);
2274 #ifndef MODULE
2275 	if (test_bit(AutoDetected, &rdev->flags))
2276 		md_autodetect_dev(rdev->bdev->bd_dev);
2277 #endif
2278 	unlock_rdev(rdev);
2279 	kobject_put(&rdev->kobj);
2280 }
2281 
2282 static void kick_rdev_from_array(struct md_rdev * rdev)
2283 {
2284 	unbind_rdev_from_array(rdev);
2285 	export_rdev(rdev);
2286 }
2287 
2288 static void export_array(struct mddev *mddev)
2289 {
2290 	struct md_rdev *rdev, *tmp;
2291 
2292 	rdev_for_each_safe(rdev, tmp, mddev) {
2293 		if (!rdev->mddev) {
2294 			MD_BUG();
2295 			continue;
2296 		}
2297 		kick_rdev_from_array(rdev);
2298 	}
2299 	if (!list_empty(&mddev->disks))
2300 		MD_BUG();
2301 	mddev->raid_disks = 0;
2302 	mddev->major_version = 0;
2303 }
2304 
2305 static void print_desc(mdp_disk_t *desc)
2306 {
2307 	printk(" DISK<N:%d,(%d,%d),R:%d,S:%d>\n", desc->number,
2308 		desc->major,desc->minor,desc->raid_disk,desc->state);
2309 }
2310 
2311 static void print_sb_90(mdp_super_t *sb)
2312 {
2313 	int i;
2314 
2315 	printk(KERN_INFO
2316 		"md:  SB: (V:%d.%d.%d) ID:<%08x.%08x.%08x.%08x> CT:%08x\n",
2317 		sb->major_version, sb->minor_version, sb->patch_version,
2318 		sb->set_uuid0, sb->set_uuid1, sb->set_uuid2, sb->set_uuid3,
2319 		sb->ctime);
2320 	printk(KERN_INFO "md:     L%d S%08d ND:%d RD:%d md%d LO:%d CS:%d\n",
2321 		sb->level, sb->size, sb->nr_disks, sb->raid_disks,
2322 		sb->md_minor, sb->layout, sb->chunk_size);
2323 	printk(KERN_INFO "md:     UT:%08x ST:%d AD:%d WD:%d"
2324 		" FD:%d SD:%d CSUM:%08x E:%08lx\n",
2325 		sb->utime, sb->state, sb->active_disks, sb->working_disks,
2326 		sb->failed_disks, sb->spare_disks,
2327 		sb->sb_csum, (unsigned long)sb->events_lo);
2328 
2329 	printk(KERN_INFO);
2330 	for (i = 0; i < MD_SB_DISKS; i++) {
2331 		mdp_disk_t *desc;
2332 
2333 		desc = sb->disks + i;
2334 		if (desc->number || desc->major || desc->minor ||
2335 		    desc->raid_disk || (desc->state && (desc->state != 4))) {
2336 			printk("     D %2d: ", i);
2337 			print_desc(desc);
2338 		}
2339 	}
2340 	printk(KERN_INFO "md:     THIS: ");
2341 	print_desc(&sb->this_disk);
2342 }
2343 
2344 static void print_sb_1(struct mdp_superblock_1 *sb)
2345 {
2346 	__u8 *uuid;
2347 
2348 	uuid = sb->set_uuid;
2349 	printk(KERN_INFO
2350 	       "md:  SB: (V:%u) (F:0x%08x) Array-ID:<%pU>\n"
2351 	       "md:    Name: \"%s\" CT:%llu\n",
2352 		le32_to_cpu(sb->major_version),
2353 		le32_to_cpu(sb->feature_map),
2354 		uuid,
2355 		sb->set_name,
2356 		(unsigned long long)le64_to_cpu(sb->ctime)
2357 		       & MD_SUPERBLOCK_1_TIME_SEC_MASK);
2358 
2359 	uuid = sb->device_uuid;
2360 	printk(KERN_INFO
2361 	       "md:       L%u SZ%llu RD:%u LO:%u CS:%u DO:%llu DS:%llu SO:%llu"
2362 			" RO:%llu\n"
2363 	       "md:     Dev:%08x UUID: %pU\n"
2364 	       "md:       (F:0x%08x) UT:%llu Events:%llu ResyncOffset:%llu CSUM:0x%08x\n"
2365 	       "md:         (MaxDev:%u) \n",
2366 		le32_to_cpu(sb->level),
2367 		(unsigned long long)le64_to_cpu(sb->size),
2368 		le32_to_cpu(sb->raid_disks),
2369 		le32_to_cpu(sb->layout),
2370 		le32_to_cpu(sb->chunksize),
2371 		(unsigned long long)le64_to_cpu(sb->data_offset),
2372 		(unsigned long long)le64_to_cpu(sb->data_size),
2373 		(unsigned long long)le64_to_cpu(sb->super_offset),
2374 		(unsigned long long)le64_to_cpu(sb->recovery_offset),
2375 		le32_to_cpu(sb->dev_number),
2376 		uuid,
2377 		sb->devflags,
2378 		(unsigned long long)le64_to_cpu(sb->utime) & MD_SUPERBLOCK_1_TIME_SEC_MASK,
2379 		(unsigned long long)le64_to_cpu(sb->events),
2380 		(unsigned long long)le64_to_cpu(sb->resync_offset),
2381 		le32_to_cpu(sb->sb_csum),
2382 		le32_to_cpu(sb->max_dev)
2383 		);
2384 }
2385 
2386 static void print_rdev(struct md_rdev *rdev, int major_version)
2387 {
2388 	char b[BDEVNAME_SIZE];
2389 	printk(KERN_INFO "md: rdev %s, Sect:%08llu F:%d S:%d DN:%u\n",
2390 		bdevname(rdev->bdev, b), (unsigned long long)rdev->sectors,
2391 	        test_bit(Faulty, &rdev->flags), test_bit(In_sync, &rdev->flags),
2392 	        rdev->desc_nr);
2393 	if (rdev->sb_loaded) {
2394 		printk(KERN_INFO "md: rdev superblock (MJ:%d):\n", major_version);
2395 		switch (major_version) {
2396 		case 0:
2397 			print_sb_90(page_address(rdev->sb_page));
2398 			break;
2399 		case 1:
2400 			print_sb_1(page_address(rdev->sb_page));
2401 			break;
2402 		}
2403 	} else
2404 		printk(KERN_INFO "md: no rdev superblock!\n");
2405 }
2406 
2407 static void md_print_devices(void)
2408 {
2409 	struct list_head *tmp;
2410 	struct md_rdev *rdev;
2411 	struct mddev *mddev;
2412 	char b[BDEVNAME_SIZE];
2413 
2414 	printk("\n");
2415 	printk("md:	**********************************\n");
2416 	printk("md:	* <COMPLETE RAID STATE PRINTOUT> *\n");
2417 	printk("md:	**********************************\n");
2418 	for_each_mddev(mddev, tmp) {
2419 
2420 		if (mddev->bitmap)
2421 			bitmap_print_sb(mddev->bitmap);
2422 		else
2423 			printk("%s: ", mdname(mddev));
2424 		rdev_for_each(rdev, mddev)
2425 			printk("<%s>", bdevname(rdev->bdev,b));
2426 		printk("\n");
2427 
2428 		rdev_for_each(rdev, mddev)
2429 			print_rdev(rdev, mddev->major_version);
2430 	}
2431 	printk("md:	**********************************\n");
2432 	printk("\n");
2433 }
2434 
2435 
2436 static void sync_sbs(struct mddev * mddev, int nospares)
2437 {
2438 	/* Update each superblock (in-memory image), but
2439 	 * if we are allowed to, skip spares which already
2440 	 * have the right event counter, or have one earlier
2441 	 * (which would mean they aren't being marked as dirty
2442 	 * with the rest of the array)
2443 	 */
2444 	struct md_rdev *rdev;
2445 	rdev_for_each(rdev, mddev) {
2446 		if (rdev->sb_events == mddev->events ||
2447 		    (nospares &&
2448 		     rdev->raid_disk < 0 &&
2449 		     rdev->sb_events+1 == mddev->events)) {
2450 			/* Don't update this superblock */
2451 			rdev->sb_loaded = 2;
2452 		} else {
2453 			sync_super(mddev, rdev);
2454 			rdev->sb_loaded = 1;
2455 		}
2456 	}
2457 }
2458 
2459 static void md_update_sb(struct mddev * mddev, int force_change)
2460 {
2461 	struct md_rdev *rdev;
2462 	int sync_req;
2463 	int nospares = 0;
2464 	int any_badblocks_changed = 0;
2465 
2466 repeat:
2467 	/* First make sure individual recovery_offsets are correct */
2468 	rdev_for_each(rdev, mddev) {
2469 		if (rdev->raid_disk >= 0 &&
2470 		    mddev->delta_disks >= 0 &&
2471 		    !test_bit(In_sync, &rdev->flags) &&
2472 		    mddev->curr_resync_completed > rdev->recovery_offset)
2473 				rdev->recovery_offset = mddev->curr_resync_completed;
2474 
2475 	}
2476 	if (!mddev->persistent) {
2477 		clear_bit(MD_CHANGE_CLEAN, &mddev->flags);
2478 		clear_bit(MD_CHANGE_DEVS, &mddev->flags);
2479 		if (!mddev->external) {
2480 			clear_bit(MD_CHANGE_PENDING, &mddev->flags);
2481 			rdev_for_each(rdev, mddev) {
2482 				if (rdev->badblocks.changed) {
2483 					rdev->badblocks.changed = 0;
2484 					md_ack_all_badblocks(&rdev->badblocks);
2485 					md_error(mddev, rdev);
2486 				}
2487 				clear_bit(Blocked, &rdev->flags);
2488 				clear_bit(BlockedBadBlocks, &rdev->flags);
2489 				wake_up(&rdev->blocked_wait);
2490 			}
2491 		}
2492 		wake_up(&mddev->sb_wait);
2493 		return;
2494 	}
2495 
2496 	spin_lock_irq(&mddev->write_lock);
2497 
2498 	mddev->utime = get_seconds();
2499 
2500 	if (test_and_clear_bit(MD_CHANGE_DEVS, &mddev->flags))
2501 		force_change = 1;
2502 	if (test_and_clear_bit(MD_CHANGE_CLEAN, &mddev->flags))
2503 		/* just a clean<-> dirty transition, possibly leave spares alone,
2504 		 * though if events isn't the right even/odd, we will have to do
2505 		 * spares after all
2506 		 */
2507 		nospares = 1;
2508 	if (force_change)
2509 		nospares = 0;
2510 	if (mddev->degraded)
2511 		/* If the array is degraded, then skipping spares is both
2512 		 * dangerous and fairly pointless.
2513 		 * Dangerous because a device that was removed from the array
2514 		 * might have a event_count that still looks up-to-date,
2515 		 * so it can be re-added without a resync.
2516 		 * Pointless because if there are any spares to skip,
2517 		 * then a recovery will happen and soon that array won't
2518 		 * be degraded any more and the spare can go back to sleep then.
2519 		 */
2520 		nospares = 0;
2521 
2522 	sync_req = mddev->in_sync;
2523 
2524 	/* If this is just a dirty<->clean transition, and the array is clean
2525 	 * and 'events' is odd, we can roll back to the previous clean state */
2526 	if (nospares
2527 	    && (mddev->in_sync && mddev->recovery_cp == MaxSector)
2528 	    && mddev->can_decrease_events
2529 	    && mddev->events != 1) {
2530 		mddev->events--;
2531 		mddev->can_decrease_events = 0;
2532 	} else {
2533 		/* otherwise we have to go forward and ... */
2534 		mddev->events ++;
2535 		mddev->can_decrease_events = nospares;
2536 	}
2537 
2538 	if (!mddev->events) {
2539 		/*
2540 		 * oops, this 64-bit counter should never wrap.
2541 		 * Either we are in around ~1 trillion A.C., assuming
2542 		 * 1 reboot per second, or we have a bug:
2543 		 */
2544 		MD_BUG();
2545 		mddev->events --;
2546 	}
2547 
2548 	rdev_for_each(rdev, mddev) {
2549 		if (rdev->badblocks.changed)
2550 			any_badblocks_changed++;
2551 		if (test_bit(Faulty, &rdev->flags))
2552 			set_bit(FaultRecorded, &rdev->flags);
2553 	}
2554 
2555 	sync_sbs(mddev, nospares);
2556 	spin_unlock_irq(&mddev->write_lock);
2557 
2558 	pr_debug("md: updating %s RAID superblock on device (in sync %d)\n",
2559 		 mdname(mddev), mddev->in_sync);
2560 
2561 	bitmap_update_sb(mddev->bitmap);
2562 	rdev_for_each(rdev, mddev) {
2563 		char b[BDEVNAME_SIZE];
2564 
2565 		if (rdev->sb_loaded != 1)
2566 			continue; /* no noise on spare devices */
2567 
2568 		if (!test_bit(Faulty, &rdev->flags) &&
2569 		    rdev->saved_raid_disk == -1) {
2570 			md_super_write(mddev,rdev,
2571 				       rdev->sb_start, rdev->sb_size,
2572 				       rdev->sb_page);
2573 			pr_debug("md: (write) %s's sb offset: %llu\n",
2574 				 bdevname(rdev->bdev, b),
2575 				 (unsigned long long)rdev->sb_start);
2576 			rdev->sb_events = mddev->events;
2577 			if (rdev->badblocks.size) {
2578 				md_super_write(mddev, rdev,
2579 					       rdev->badblocks.sector,
2580 					       rdev->badblocks.size << 9,
2581 					       rdev->bb_page);
2582 				rdev->badblocks.size = 0;
2583 			}
2584 
2585 		} else if (test_bit(Faulty, &rdev->flags))
2586 			pr_debug("md: %s (skipping faulty)\n",
2587 				 bdevname(rdev->bdev, b));
2588 		else
2589 			pr_debug("(skipping incremental s/r ");
2590 
2591 		if (mddev->level == LEVEL_MULTIPATH)
2592 			/* only need to write one superblock... */
2593 			break;
2594 	}
2595 	md_super_wait(mddev);
2596 	/* if there was a failure, MD_CHANGE_DEVS was set, and we re-write super */
2597 
2598 	spin_lock_irq(&mddev->write_lock);
2599 	if (mddev->in_sync != sync_req ||
2600 	    test_bit(MD_CHANGE_DEVS, &mddev->flags)) {
2601 		/* have to write it out again */
2602 		spin_unlock_irq(&mddev->write_lock);
2603 		goto repeat;
2604 	}
2605 	clear_bit(MD_CHANGE_PENDING, &mddev->flags);
2606 	spin_unlock_irq(&mddev->write_lock);
2607 	wake_up(&mddev->sb_wait);
2608 	if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
2609 		sysfs_notify(&mddev->kobj, NULL, "sync_completed");
2610 
2611 	rdev_for_each(rdev, mddev) {
2612 		if (test_and_clear_bit(FaultRecorded, &rdev->flags))
2613 			clear_bit(Blocked, &rdev->flags);
2614 
2615 		if (any_badblocks_changed)
2616 			md_ack_all_badblocks(&rdev->badblocks);
2617 		clear_bit(BlockedBadBlocks, &rdev->flags);
2618 		wake_up(&rdev->blocked_wait);
2619 	}
2620 }
2621 
2622 /* words written to sysfs files may, or may not, be \n terminated.
2623  * We want to accept with case. For this we use cmd_match.
2624  */
2625 static int cmd_match(const char *cmd, const char *str)
2626 {
2627 	/* See if cmd, written into a sysfs file, matches
2628 	 * str.  They must either be the same, or cmd can
2629 	 * have a trailing newline
2630 	 */
2631 	while (*cmd && *str && *cmd == *str) {
2632 		cmd++;
2633 		str++;
2634 	}
2635 	if (*cmd == '\n')
2636 		cmd++;
2637 	if (*str || *cmd)
2638 		return 0;
2639 	return 1;
2640 }
2641 
2642 struct rdev_sysfs_entry {
2643 	struct attribute attr;
2644 	ssize_t (*show)(struct md_rdev *, char *);
2645 	ssize_t (*store)(struct md_rdev *, const char *, size_t);
2646 };
2647 
2648 static ssize_t
2649 state_show(struct md_rdev *rdev, char *page)
2650 {
2651 	char *sep = "";
2652 	size_t len = 0;
2653 
2654 	if (test_bit(Faulty, &rdev->flags) ||
2655 	    rdev->badblocks.unacked_exist) {
2656 		len+= sprintf(page+len, "%sfaulty",sep);
2657 		sep = ",";
2658 	}
2659 	if (test_bit(In_sync, &rdev->flags)) {
2660 		len += sprintf(page+len, "%sin_sync",sep);
2661 		sep = ",";
2662 	}
2663 	if (test_bit(WriteMostly, &rdev->flags)) {
2664 		len += sprintf(page+len, "%swrite_mostly",sep);
2665 		sep = ",";
2666 	}
2667 	if (test_bit(Blocked, &rdev->flags) ||
2668 	    (rdev->badblocks.unacked_exist
2669 	     && !test_bit(Faulty, &rdev->flags))) {
2670 		len += sprintf(page+len, "%sblocked", sep);
2671 		sep = ",";
2672 	}
2673 	if (!test_bit(Faulty, &rdev->flags) &&
2674 	    !test_bit(In_sync, &rdev->flags)) {
2675 		len += sprintf(page+len, "%sspare", sep);
2676 		sep = ",";
2677 	}
2678 	if (test_bit(WriteErrorSeen, &rdev->flags)) {
2679 		len += sprintf(page+len, "%swrite_error", sep);
2680 		sep = ",";
2681 	}
2682 	if (test_bit(WantReplacement, &rdev->flags)) {
2683 		len += sprintf(page+len, "%swant_replacement", sep);
2684 		sep = ",";
2685 	}
2686 	if (test_bit(Replacement, &rdev->flags)) {
2687 		len += sprintf(page+len, "%sreplacement", sep);
2688 		sep = ",";
2689 	}
2690 
2691 	return len+sprintf(page+len, "\n");
2692 }
2693 
2694 static ssize_t
2695 state_store(struct md_rdev *rdev, const char *buf, size_t len)
2696 {
2697 	/* can write
2698 	 *  faulty  - simulates an error
2699 	 *  remove  - disconnects the device
2700 	 *  writemostly - sets write_mostly
2701 	 *  -writemostly - clears write_mostly
2702 	 *  blocked - sets the Blocked flags
2703 	 *  -blocked - clears the Blocked and possibly simulates an error
2704 	 *  insync - sets Insync providing device isn't active
2705 	 *  write_error - sets WriteErrorSeen
2706 	 *  -write_error - clears WriteErrorSeen
2707 	 */
2708 	int err = -EINVAL;
2709 	if (cmd_match(buf, "faulty") && rdev->mddev->pers) {
2710 		md_error(rdev->mddev, rdev);
2711 		if (test_bit(Faulty, &rdev->flags))
2712 			err = 0;
2713 		else
2714 			err = -EBUSY;
2715 	} else if (cmd_match(buf, "remove")) {
2716 		if (rdev->raid_disk >= 0)
2717 			err = -EBUSY;
2718 		else {
2719 			struct mddev *mddev = rdev->mddev;
2720 			kick_rdev_from_array(rdev);
2721 			if (mddev->pers)
2722 				md_update_sb(mddev, 1);
2723 			md_new_event(mddev);
2724 			err = 0;
2725 		}
2726 	} else if (cmd_match(buf, "writemostly")) {
2727 		set_bit(WriteMostly, &rdev->flags);
2728 		err = 0;
2729 	} else if (cmd_match(buf, "-writemostly")) {
2730 		clear_bit(WriteMostly, &rdev->flags);
2731 		err = 0;
2732 	} else if (cmd_match(buf, "blocked")) {
2733 		set_bit(Blocked, &rdev->flags);
2734 		err = 0;
2735 	} else if (cmd_match(buf, "-blocked")) {
2736 		if (!test_bit(Faulty, &rdev->flags) &&
2737 		    rdev->badblocks.unacked_exist) {
2738 			/* metadata handler doesn't understand badblocks,
2739 			 * so we need to fail the device
2740 			 */
2741 			md_error(rdev->mddev, rdev);
2742 		}
2743 		clear_bit(Blocked, &rdev->flags);
2744 		clear_bit(BlockedBadBlocks, &rdev->flags);
2745 		wake_up(&rdev->blocked_wait);
2746 		set_bit(MD_RECOVERY_NEEDED, &rdev->mddev->recovery);
2747 		md_wakeup_thread(rdev->mddev->thread);
2748 
2749 		err = 0;
2750 	} else if (cmd_match(buf, "insync") && rdev->raid_disk == -1) {
2751 		set_bit(In_sync, &rdev->flags);
2752 		err = 0;
2753 	} else if (cmd_match(buf, "write_error")) {
2754 		set_bit(WriteErrorSeen, &rdev->flags);
2755 		err = 0;
2756 	} else if (cmd_match(buf, "-write_error")) {
2757 		clear_bit(WriteErrorSeen, &rdev->flags);
2758 		err = 0;
2759 	} else if (cmd_match(buf, "want_replacement")) {
2760 		/* Any non-spare device that is not a replacement can
2761 		 * become want_replacement at any time, but we then need to
2762 		 * check if recovery is needed.
2763 		 */
2764 		if (rdev->raid_disk >= 0 &&
2765 		    !test_bit(Replacement, &rdev->flags))
2766 			set_bit(WantReplacement, &rdev->flags);
2767 		set_bit(MD_RECOVERY_NEEDED, &rdev->mddev->recovery);
2768 		md_wakeup_thread(rdev->mddev->thread);
2769 		err = 0;
2770 	} else if (cmd_match(buf, "-want_replacement")) {
2771 		/* Clearing 'want_replacement' is always allowed.
2772 		 * Once replacements starts it is too late though.
2773 		 */
2774 		err = 0;
2775 		clear_bit(WantReplacement, &rdev->flags);
2776 	} else if (cmd_match(buf, "replacement")) {
2777 		/* Can only set a device as a replacement when array has not
2778 		 * yet been started.  Once running, replacement is automatic
2779 		 * from spares, or by assigning 'slot'.
2780 		 */
2781 		if (rdev->mddev->pers)
2782 			err = -EBUSY;
2783 		else {
2784 			set_bit(Replacement, &rdev->flags);
2785 			err = 0;
2786 		}
2787 	} else if (cmd_match(buf, "-replacement")) {
2788 		/* Similarly, can only clear Replacement before start */
2789 		if (rdev->mddev->pers)
2790 			err = -EBUSY;
2791 		else {
2792 			clear_bit(Replacement, &rdev->flags);
2793 			err = 0;
2794 		}
2795 	}
2796 	if (!err)
2797 		sysfs_notify_dirent_safe(rdev->sysfs_state);
2798 	return err ? err : len;
2799 }
2800 static struct rdev_sysfs_entry rdev_state =
2801 __ATTR(state, S_IRUGO|S_IWUSR, state_show, state_store);
2802 
2803 static ssize_t
2804 errors_show(struct md_rdev *rdev, char *page)
2805 {
2806 	return sprintf(page, "%d\n", atomic_read(&rdev->corrected_errors));
2807 }
2808 
2809 static ssize_t
2810 errors_store(struct md_rdev *rdev, const char *buf, size_t len)
2811 {
2812 	char *e;
2813 	unsigned long n = simple_strtoul(buf, &e, 10);
2814 	if (*buf && (*e == 0 || *e == '\n')) {
2815 		atomic_set(&rdev->corrected_errors, n);
2816 		return len;
2817 	}
2818 	return -EINVAL;
2819 }
2820 static struct rdev_sysfs_entry rdev_errors =
2821 __ATTR(errors, S_IRUGO|S_IWUSR, errors_show, errors_store);
2822 
2823 static ssize_t
2824 slot_show(struct md_rdev *rdev, char *page)
2825 {
2826 	if (rdev->raid_disk < 0)
2827 		return sprintf(page, "none\n");
2828 	else
2829 		return sprintf(page, "%d\n", rdev->raid_disk);
2830 }
2831 
2832 static ssize_t
2833 slot_store(struct md_rdev *rdev, const char *buf, size_t len)
2834 {
2835 	char *e;
2836 	int err;
2837 	int slot = simple_strtoul(buf, &e, 10);
2838 	if (strncmp(buf, "none", 4)==0)
2839 		slot = -1;
2840 	else if (e==buf || (*e && *e!= '\n'))
2841 		return -EINVAL;
2842 	if (rdev->mddev->pers && slot == -1) {
2843 		/* Setting 'slot' on an active array requires also
2844 		 * updating the 'rd%d' link, and communicating
2845 		 * with the personality with ->hot_*_disk.
2846 		 * For now we only support removing
2847 		 * failed/spare devices.  This normally happens automatically,
2848 		 * but not when the metadata is externally managed.
2849 		 */
2850 		if (rdev->raid_disk == -1)
2851 			return -EEXIST;
2852 		/* personality does all needed checks */
2853 		if (rdev->mddev->pers->hot_remove_disk == NULL)
2854 			return -EINVAL;
2855 		err = rdev->mddev->pers->
2856 			hot_remove_disk(rdev->mddev, rdev);
2857 		if (err)
2858 			return err;
2859 		sysfs_unlink_rdev(rdev->mddev, rdev);
2860 		rdev->raid_disk = -1;
2861 		set_bit(MD_RECOVERY_NEEDED, &rdev->mddev->recovery);
2862 		md_wakeup_thread(rdev->mddev->thread);
2863 	} else if (rdev->mddev->pers) {
2864 		/* Activating a spare .. or possibly reactivating
2865 		 * if we ever get bitmaps working here.
2866 		 */
2867 
2868 		if (rdev->raid_disk != -1)
2869 			return -EBUSY;
2870 
2871 		if (test_bit(MD_RECOVERY_RUNNING, &rdev->mddev->recovery))
2872 			return -EBUSY;
2873 
2874 		if (rdev->mddev->pers->hot_add_disk == NULL)
2875 			return -EINVAL;
2876 
2877 		if (slot >= rdev->mddev->raid_disks &&
2878 		    slot >= rdev->mddev->raid_disks + rdev->mddev->delta_disks)
2879 			return -ENOSPC;
2880 
2881 		rdev->raid_disk = slot;
2882 		if (test_bit(In_sync, &rdev->flags))
2883 			rdev->saved_raid_disk = slot;
2884 		else
2885 			rdev->saved_raid_disk = -1;
2886 		clear_bit(In_sync, &rdev->flags);
2887 		err = rdev->mddev->pers->
2888 			hot_add_disk(rdev->mddev, rdev);
2889 		if (err) {
2890 			rdev->raid_disk = -1;
2891 			return err;
2892 		} else
2893 			sysfs_notify_dirent_safe(rdev->sysfs_state);
2894 		if (sysfs_link_rdev(rdev->mddev, rdev))
2895 			/* failure here is OK */;
2896 		/* don't wakeup anyone, leave that to userspace. */
2897 	} else {
2898 		if (slot >= rdev->mddev->raid_disks &&
2899 		    slot >= rdev->mddev->raid_disks + rdev->mddev->delta_disks)
2900 			return -ENOSPC;
2901 		rdev->raid_disk = slot;
2902 		/* assume it is working */
2903 		clear_bit(Faulty, &rdev->flags);
2904 		clear_bit(WriteMostly, &rdev->flags);
2905 		set_bit(In_sync, &rdev->flags);
2906 		sysfs_notify_dirent_safe(rdev->sysfs_state);
2907 	}
2908 	return len;
2909 }
2910 
2911 
2912 static struct rdev_sysfs_entry rdev_slot =
2913 __ATTR(slot, S_IRUGO|S_IWUSR, slot_show, slot_store);
2914 
2915 static ssize_t
2916 offset_show(struct md_rdev *rdev, char *page)
2917 {
2918 	return sprintf(page, "%llu\n", (unsigned long long)rdev->data_offset);
2919 }
2920 
2921 static ssize_t
2922 offset_store(struct md_rdev *rdev, const char *buf, size_t len)
2923 {
2924 	unsigned long long offset;
2925 	if (strict_strtoull(buf, 10, &offset) < 0)
2926 		return -EINVAL;
2927 	if (rdev->mddev->pers && rdev->raid_disk >= 0)
2928 		return -EBUSY;
2929 	if (rdev->sectors && rdev->mddev->external)
2930 		/* Must set offset before size, so overlap checks
2931 		 * can be sane */
2932 		return -EBUSY;
2933 	rdev->data_offset = offset;
2934 	return len;
2935 }
2936 
2937 static struct rdev_sysfs_entry rdev_offset =
2938 __ATTR(offset, S_IRUGO|S_IWUSR, offset_show, offset_store);
2939 
2940 static ssize_t new_offset_show(struct md_rdev *rdev, char *page)
2941 {
2942 	return sprintf(page, "%llu\n",
2943 		       (unsigned long long)rdev->new_data_offset);
2944 }
2945 
2946 static ssize_t new_offset_store(struct md_rdev *rdev,
2947 				const char *buf, size_t len)
2948 {
2949 	unsigned long long new_offset;
2950 	struct mddev *mddev = rdev->mddev;
2951 
2952 	if (strict_strtoull(buf, 10, &new_offset) < 0)
2953 		return -EINVAL;
2954 
2955 	if (mddev->sync_thread)
2956 		return -EBUSY;
2957 	if (new_offset == rdev->data_offset)
2958 		/* reset is always permitted */
2959 		;
2960 	else if (new_offset > rdev->data_offset) {
2961 		/* must not push array size beyond rdev_sectors */
2962 		if (new_offset - rdev->data_offset
2963 		    + mddev->dev_sectors > rdev->sectors)
2964 				return -E2BIG;
2965 	}
2966 	/* Metadata worries about other space details. */
2967 
2968 	/* decreasing the offset is inconsistent with a backwards
2969 	 * reshape.
2970 	 */
2971 	if (new_offset < rdev->data_offset &&
2972 	    mddev->reshape_backwards)
2973 		return -EINVAL;
2974 	/* Increasing offset is inconsistent with forwards
2975 	 * reshape.  reshape_direction should be set to
2976 	 * 'backwards' first.
2977 	 */
2978 	if (new_offset > rdev->data_offset &&
2979 	    !mddev->reshape_backwards)
2980 		return -EINVAL;
2981 
2982 	if (mddev->pers && mddev->persistent &&
2983 	    !super_types[mddev->major_version]
2984 	    .allow_new_offset(rdev, new_offset))
2985 		return -E2BIG;
2986 	rdev->new_data_offset = new_offset;
2987 	if (new_offset > rdev->data_offset)
2988 		mddev->reshape_backwards = 1;
2989 	else if (new_offset < rdev->data_offset)
2990 		mddev->reshape_backwards = 0;
2991 
2992 	return len;
2993 }
2994 static struct rdev_sysfs_entry rdev_new_offset =
2995 __ATTR(new_offset, S_IRUGO|S_IWUSR, new_offset_show, new_offset_store);
2996 
2997 static ssize_t
2998 rdev_size_show(struct md_rdev *rdev, char *page)
2999 {
3000 	return sprintf(page, "%llu\n", (unsigned long long)rdev->sectors / 2);
3001 }
3002 
3003 static int overlaps(sector_t s1, sector_t l1, sector_t s2, sector_t l2)
3004 {
3005 	/* check if two start/length pairs overlap */
3006 	if (s1+l1 <= s2)
3007 		return 0;
3008 	if (s2+l2 <= s1)
3009 		return 0;
3010 	return 1;
3011 }
3012 
3013 static int strict_blocks_to_sectors(const char *buf, sector_t *sectors)
3014 {
3015 	unsigned long long blocks;
3016 	sector_t new;
3017 
3018 	if (strict_strtoull(buf, 10, &blocks) < 0)
3019 		return -EINVAL;
3020 
3021 	if (blocks & 1ULL << (8 * sizeof(blocks) - 1))
3022 		return -EINVAL; /* sector conversion overflow */
3023 
3024 	new = blocks * 2;
3025 	if (new != blocks * 2)
3026 		return -EINVAL; /* unsigned long long to sector_t overflow */
3027 
3028 	*sectors = new;
3029 	return 0;
3030 }
3031 
3032 static ssize_t
3033 rdev_size_store(struct md_rdev *rdev, const char *buf, size_t len)
3034 {
3035 	struct mddev *my_mddev = rdev->mddev;
3036 	sector_t oldsectors = rdev->sectors;
3037 	sector_t sectors;
3038 
3039 	if (strict_blocks_to_sectors(buf, &sectors) < 0)
3040 		return -EINVAL;
3041 	if (rdev->data_offset != rdev->new_data_offset)
3042 		return -EINVAL; /* too confusing */
3043 	if (my_mddev->pers && rdev->raid_disk >= 0) {
3044 		if (my_mddev->persistent) {
3045 			sectors = super_types[my_mddev->major_version].
3046 				rdev_size_change(rdev, sectors);
3047 			if (!sectors)
3048 				return -EBUSY;
3049 		} else if (!sectors)
3050 			sectors = (i_size_read(rdev->bdev->bd_inode) >> 9) -
3051 				rdev->data_offset;
3052 	}
3053 	if (sectors < my_mddev->dev_sectors)
3054 		return -EINVAL; /* component must fit device */
3055 
3056 	rdev->sectors = sectors;
3057 	if (sectors > oldsectors && my_mddev->external) {
3058 		/* need to check that all other rdevs with the same ->bdev
3059 		 * do not overlap.  We need to unlock the mddev to avoid
3060 		 * a deadlock.  We have already changed rdev->sectors, and if
3061 		 * we have to change it back, we will have the lock again.
3062 		 */
3063 		struct mddev *mddev;
3064 		int overlap = 0;
3065 		struct list_head *tmp;
3066 
3067 		mddev_unlock(my_mddev);
3068 		for_each_mddev(mddev, tmp) {
3069 			struct md_rdev *rdev2;
3070 
3071 			mddev_lock(mddev);
3072 			rdev_for_each(rdev2, mddev)
3073 				if (rdev->bdev == rdev2->bdev &&
3074 				    rdev != rdev2 &&
3075 				    overlaps(rdev->data_offset, rdev->sectors,
3076 					     rdev2->data_offset,
3077 					     rdev2->sectors)) {
3078 					overlap = 1;
3079 					break;
3080 				}
3081 			mddev_unlock(mddev);
3082 			if (overlap) {
3083 				mddev_put(mddev);
3084 				break;
3085 			}
3086 		}
3087 		mddev_lock(my_mddev);
3088 		if (overlap) {
3089 			/* Someone else could have slipped in a size
3090 			 * change here, but doing so is just silly.
3091 			 * We put oldsectors back because we *know* it is
3092 			 * safe, and trust userspace not to race with
3093 			 * itself
3094 			 */
3095 			rdev->sectors = oldsectors;
3096 			return -EBUSY;
3097 		}
3098 	}
3099 	return len;
3100 }
3101 
3102 static struct rdev_sysfs_entry rdev_size =
3103 __ATTR(size, S_IRUGO|S_IWUSR, rdev_size_show, rdev_size_store);
3104 
3105 
3106 static ssize_t recovery_start_show(struct md_rdev *rdev, char *page)
3107 {
3108 	unsigned long long recovery_start = rdev->recovery_offset;
3109 
3110 	if (test_bit(In_sync, &rdev->flags) ||
3111 	    recovery_start == MaxSector)
3112 		return sprintf(page, "none\n");
3113 
3114 	return sprintf(page, "%llu\n", recovery_start);
3115 }
3116 
3117 static ssize_t recovery_start_store(struct md_rdev *rdev, const char *buf, size_t len)
3118 {
3119 	unsigned long long recovery_start;
3120 
3121 	if (cmd_match(buf, "none"))
3122 		recovery_start = MaxSector;
3123 	else if (strict_strtoull(buf, 10, &recovery_start))
3124 		return -EINVAL;
3125 
3126 	if (rdev->mddev->pers &&
3127 	    rdev->raid_disk >= 0)
3128 		return -EBUSY;
3129 
3130 	rdev->recovery_offset = recovery_start;
3131 	if (recovery_start == MaxSector)
3132 		set_bit(In_sync, &rdev->flags);
3133 	else
3134 		clear_bit(In_sync, &rdev->flags);
3135 	return len;
3136 }
3137 
3138 static struct rdev_sysfs_entry rdev_recovery_start =
3139 __ATTR(recovery_start, S_IRUGO|S_IWUSR, recovery_start_show, recovery_start_store);
3140 
3141 
3142 static ssize_t
3143 badblocks_show(struct badblocks *bb, char *page, int unack);
3144 static ssize_t
3145 badblocks_store(struct badblocks *bb, const char *page, size_t len, int unack);
3146 
3147 static ssize_t bb_show(struct md_rdev *rdev, char *page)
3148 {
3149 	return badblocks_show(&rdev->badblocks, page, 0);
3150 }
3151 static ssize_t bb_store(struct md_rdev *rdev, const char *page, size_t len)
3152 {
3153 	int rv = badblocks_store(&rdev->badblocks, page, len, 0);
3154 	/* Maybe that ack was all we needed */
3155 	if (test_and_clear_bit(BlockedBadBlocks, &rdev->flags))
3156 		wake_up(&rdev->blocked_wait);
3157 	return rv;
3158 }
3159 static struct rdev_sysfs_entry rdev_bad_blocks =
3160 __ATTR(bad_blocks, S_IRUGO|S_IWUSR, bb_show, bb_store);
3161 
3162 
3163 static ssize_t ubb_show(struct md_rdev *rdev, char *page)
3164 {
3165 	return badblocks_show(&rdev->badblocks, page, 1);
3166 }
3167 static ssize_t ubb_store(struct md_rdev *rdev, const char *page, size_t len)
3168 {
3169 	return badblocks_store(&rdev->badblocks, page, len, 1);
3170 }
3171 static struct rdev_sysfs_entry rdev_unack_bad_blocks =
3172 __ATTR(unacknowledged_bad_blocks, S_IRUGO|S_IWUSR, ubb_show, ubb_store);
3173 
3174 static struct attribute *rdev_default_attrs[] = {
3175 	&rdev_state.attr,
3176 	&rdev_errors.attr,
3177 	&rdev_slot.attr,
3178 	&rdev_offset.attr,
3179 	&rdev_new_offset.attr,
3180 	&rdev_size.attr,
3181 	&rdev_recovery_start.attr,
3182 	&rdev_bad_blocks.attr,
3183 	&rdev_unack_bad_blocks.attr,
3184 	NULL,
3185 };
3186 static ssize_t
3187 rdev_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
3188 {
3189 	struct rdev_sysfs_entry *entry = container_of(attr, struct rdev_sysfs_entry, attr);
3190 	struct md_rdev *rdev = container_of(kobj, struct md_rdev, kobj);
3191 	struct mddev *mddev = rdev->mddev;
3192 	ssize_t rv;
3193 
3194 	if (!entry->show)
3195 		return -EIO;
3196 
3197 	rv = mddev ? mddev_lock(mddev) : -EBUSY;
3198 	if (!rv) {
3199 		if (rdev->mddev == NULL)
3200 			rv = -EBUSY;
3201 		else
3202 			rv = entry->show(rdev, page);
3203 		mddev_unlock(mddev);
3204 	}
3205 	return rv;
3206 }
3207 
3208 static ssize_t
3209 rdev_attr_store(struct kobject *kobj, struct attribute *attr,
3210 	      const char *page, size_t length)
3211 {
3212 	struct rdev_sysfs_entry *entry = container_of(attr, struct rdev_sysfs_entry, attr);
3213 	struct md_rdev *rdev = container_of(kobj, struct md_rdev, kobj);
3214 	ssize_t rv;
3215 	struct mddev *mddev = rdev->mddev;
3216 
3217 	if (!entry->store)
3218 		return -EIO;
3219 	if (!capable(CAP_SYS_ADMIN))
3220 		return -EACCES;
3221 	rv = mddev ? mddev_lock(mddev): -EBUSY;
3222 	if (!rv) {
3223 		if (rdev->mddev == NULL)
3224 			rv = -EBUSY;
3225 		else
3226 			rv = entry->store(rdev, page, length);
3227 		mddev_unlock(mddev);
3228 	}
3229 	return rv;
3230 }
3231 
3232 static void rdev_free(struct kobject *ko)
3233 {
3234 	struct md_rdev *rdev = container_of(ko, struct md_rdev, kobj);
3235 	kfree(rdev);
3236 }
3237 static const struct sysfs_ops rdev_sysfs_ops = {
3238 	.show		= rdev_attr_show,
3239 	.store		= rdev_attr_store,
3240 };
3241 static struct kobj_type rdev_ktype = {
3242 	.release	= rdev_free,
3243 	.sysfs_ops	= &rdev_sysfs_ops,
3244 	.default_attrs	= rdev_default_attrs,
3245 };
3246 
3247 int md_rdev_init(struct md_rdev *rdev)
3248 {
3249 	rdev->desc_nr = -1;
3250 	rdev->saved_raid_disk = -1;
3251 	rdev->raid_disk = -1;
3252 	rdev->flags = 0;
3253 	rdev->data_offset = 0;
3254 	rdev->new_data_offset = 0;
3255 	rdev->sb_events = 0;
3256 	rdev->last_read_error.tv_sec  = 0;
3257 	rdev->last_read_error.tv_nsec = 0;
3258 	rdev->sb_loaded = 0;
3259 	rdev->bb_page = NULL;
3260 	atomic_set(&rdev->nr_pending, 0);
3261 	atomic_set(&rdev->read_errors, 0);
3262 	atomic_set(&rdev->corrected_errors, 0);
3263 
3264 	INIT_LIST_HEAD(&rdev->same_set);
3265 	init_waitqueue_head(&rdev->blocked_wait);
3266 
3267 	/* Add space to store bad block list.
3268 	 * This reserves the space even on arrays where it cannot
3269 	 * be used - I wonder if that matters
3270 	 */
3271 	rdev->badblocks.count = 0;
3272 	rdev->badblocks.shift = 0;
3273 	rdev->badblocks.page = kmalloc(PAGE_SIZE, GFP_KERNEL);
3274 	seqlock_init(&rdev->badblocks.lock);
3275 	if (rdev->badblocks.page == NULL)
3276 		return -ENOMEM;
3277 
3278 	return 0;
3279 }
3280 EXPORT_SYMBOL_GPL(md_rdev_init);
3281 /*
3282  * Import a device. If 'super_format' >= 0, then sanity check the superblock
3283  *
3284  * mark the device faulty if:
3285  *
3286  *   - the device is nonexistent (zero size)
3287  *   - the device has no valid superblock
3288  *
3289  * a faulty rdev _never_ has rdev->sb set.
3290  */
3291 static struct md_rdev *md_import_device(dev_t newdev, int super_format, int super_minor)
3292 {
3293 	char b[BDEVNAME_SIZE];
3294 	int err;
3295 	struct md_rdev *rdev;
3296 	sector_t size;
3297 
3298 	rdev = kzalloc(sizeof(*rdev), GFP_KERNEL);
3299 	if (!rdev) {
3300 		printk(KERN_ERR "md: could not alloc mem for new device!\n");
3301 		return ERR_PTR(-ENOMEM);
3302 	}
3303 
3304 	err = md_rdev_init(rdev);
3305 	if (err)
3306 		goto abort_free;
3307 	err = alloc_disk_sb(rdev);
3308 	if (err)
3309 		goto abort_free;
3310 
3311 	err = lock_rdev(rdev, newdev, super_format == -2);
3312 	if (err)
3313 		goto abort_free;
3314 
3315 	kobject_init(&rdev->kobj, &rdev_ktype);
3316 
3317 	size = i_size_read(rdev->bdev->bd_inode) >> BLOCK_SIZE_BITS;
3318 	if (!size) {
3319 		printk(KERN_WARNING
3320 			"md: %s has zero or unknown size, marking faulty!\n",
3321 			bdevname(rdev->bdev,b));
3322 		err = -EINVAL;
3323 		goto abort_free;
3324 	}
3325 
3326 	if (super_format >= 0) {
3327 		err = super_types[super_format].
3328 			load_super(rdev, NULL, super_minor);
3329 		if (err == -EINVAL) {
3330 			printk(KERN_WARNING
3331 				"md: %s does not have a valid v%d.%d "
3332 			       "superblock, not importing!\n",
3333 				bdevname(rdev->bdev,b),
3334 			       super_format, super_minor);
3335 			goto abort_free;
3336 		}
3337 		if (err < 0) {
3338 			printk(KERN_WARNING
3339 				"md: could not read %s's sb, not importing!\n",
3340 				bdevname(rdev->bdev,b));
3341 			goto abort_free;
3342 		}
3343 	}
3344 	if (super_format == -1)
3345 		/* hot-add for 0.90, or non-persistent: so no badblocks */
3346 		rdev->badblocks.shift = -1;
3347 
3348 	return rdev;
3349 
3350 abort_free:
3351 	if (rdev->bdev)
3352 		unlock_rdev(rdev);
3353 	md_rdev_clear(rdev);
3354 	kfree(rdev);
3355 	return ERR_PTR(err);
3356 }
3357 
3358 /*
3359  * Check a full RAID array for plausibility
3360  */
3361 
3362 
3363 static void analyze_sbs(struct mddev * mddev)
3364 {
3365 	int i;
3366 	struct md_rdev *rdev, *freshest, *tmp;
3367 	char b[BDEVNAME_SIZE];
3368 
3369 	freshest = NULL;
3370 	rdev_for_each_safe(rdev, tmp, mddev)
3371 		switch (super_types[mddev->major_version].
3372 			load_super(rdev, freshest, mddev->minor_version)) {
3373 		case 1:
3374 			freshest = rdev;
3375 			break;
3376 		case 0:
3377 			break;
3378 		default:
3379 			printk( KERN_ERR \
3380 				"md: fatal superblock inconsistency in %s"
3381 				" -- removing from array\n",
3382 				bdevname(rdev->bdev,b));
3383 			kick_rdev_from_array(rdev);
3384 		}
3385 
3386 
3387 	super_types[mddev->major_version].
3388 		validate_super(mddev, freshest);
3389 
3390 	i = 0;
3391 	rdev_for_each_safe(rdev, tmp, mddev) {
3392 		if (mddev->max_disks &&
3393 		    (rdev->desc_nr >= mddev->max_disks ||
3394 		     i > mddev->max_disks)) {
3395 			printk(KERN_WARNING
3396 			       "md: %s: %s: only %d devices permitted\n",
3397 			       mdname(mddev), bdevname(rdev->bdev, b),
3398 			       mddev->max_disks);
3399 			kick_rdev_from_array(rdev);
3400 			continue;
3401 		}
3402 		if (rdev != freshest)
3403 			if (super_types[mddev->major_version].
3404 			    validate_super(mddev, rdev)) {
3405 				printk(KERN_WARNING "md: kicking non-fresh %s"
3406 					" from array!\n",
3407 					bdevname(rdev->bdev,b));
3408 				kick_rdev_from_array(rdev);
3409 				continue;
3410 			}
3411 		if (mddev->level == LEVEL_MULTIPATH) {
3412 			rdev->desc_nr = i++;
3413 			rdev->raid_disk = rdev->desc_nr;
3414 			set_bit(In_sync, &rdev->flags);
3415 		} else if (rdev->raid_disk >= (mddev->raid_disks - min(0, mddev->delta_disks))) {
3416 			rdev->raid_disk = -1;
3417 			clear_bit(In_sync, &rdev->flags);
3418 		}
3419 	}
3420 }
3421 
3422 /* Read a fixed-point number.
3423  * Numbers in sysfs attributes should be in "standard" units where
3424  * possible, so time should be in seconds.
3425  * However we internally use a a much smaller unit such as
3426  * milliseconds or jiffies.
3427  * This function takes a decimal number with a possible fractional
3428  * component, and produces an integer which is the result of
3429  * multiplying that number by 10^'scale'.
3430  * all without any floating-point arithmetic.
3431  */
3432 int strict_strtoul_scaled(const char *cp, unsigned long *res, int scale)
3433 {
3434 	unsigned long result = 0;
3435 	long decimals = -1;
3436 	while (isdigit(*cp) || (*cp == '.' && decimals < 0)) {
3437 		if (*cp == '.')
3438 			decimals = 0;
3439 		else if (decimals < scale) {
3440 			unsigned int value;
3441 			value = *cp - '0';
3442 			result = result * 10 + value;
3443 			if (decimals >= 0)
3444 				decimals++;
3445 		}
3446 		cp++;
3447 	}
3448 	if (*cp == '\n')
3449 		cp++;
3450 	if (*cp)
3451 		return -EINVAL;
3452 	if (decimals < 0)
3453 		decimals = 0;
3454 	while (decimals < scale) {
3455 		result *= 10;
3456 		decimals ++;
3457 	}
3458 	*res = result;
3459 	return 0;
3460 }
3461 
3462 
3463 static void md_safemode_timeout(unsigned long data);
3464 
3465 static ssize_t
3466 safe_delay_show(struct mddev *mddev, char *page)
3467 {
3468 	int msec = (mddev->safemode_delay*1000)/HZ;
3469 	return sprintf(page, "%d.%03d\n", msec/1000, msec%1000);
3470 }
3471 static ssize_t
3472 safe_delay_store(struct mddev *mddev, const char *cbuf, size_t len)
3473 {
3474 	unsigned long msec;
3475 
3476 	if (strict_strtoul_scaled(cbuf, &msec, 3) < 0)
3477 		return -EINVAL;
3478 	if (msec == 0)
3479 		mddev->safemode_delay = 0;
3480 	else {
3481 		unsigned long old_delay = mddev->safemode_delay;
3482 		mddev->safemode_delay = (msec*HZ)/1000;
3483 		if (mddev->safemode_delay == 0)
3484 			mddev->safemode_delay = 1;
3485 		if (mddev->safemode_delay < old_delay)
3486 			md_safemode_timeout((unsigned long)mddev);
3487 	}
3488 	return len;
3489 }
3490 static struct md_sysfs_entry md_safe_delay =
3491 __ATTR(safe_mode_delay, S_IRUGO|S_IWUSR,safe_delay_show, safe_delay_store);
3492 
3493 static ssize_t
3494 level_show(struct mddev *mddev, char *page)
3495 {
3496 	struct md_personality *p = mddev->pers;
3497 	if (p)
3498 		return sprintf(page, "%s\n", p->name);
3499 	else if (mddev->clevel[0])
3500 		return sprintf(page, "%s\n", mddev->clevel);
3501 	else if (mddev->level != LEVEL_NONE)
3502 		return sprintf(page, "%d\n", mddev->level);
3503 	else
3504 		return 0;
3505 }
3506 
3507 static ssize_t
3508 level_store(struct mddev *mddev, const char *buf, size_t len)
3509 {
3510 	char clevel[16];
3511 	ssize_t rv = len;
3512 	struct md_personality *pers;
3513 	long level;
3514 	void *priv;
3515 	struct md_rdev *rdev;
3516 
3517 	if (mddev->pers == NULL) {
3518 		if (len == 0)
3519 			return 0;
3520 		if (len >= sizeof(mddev->clevel))
3521 			return -ENOSPC;
3522 		strncpy(mddev->clevel, buf, len);
3523 		if (mddev->clevel[len-1] == '\n')
3524 			len--;
3525 		mddev->clevel[len] = 0;
3526 		mddev->level = LEVEL_NONE;
3527 		return rv;
3528 	}
3529 
3530 	/* request to change the personality.  Need to ensure:
3531 	 *  - array is not engaged in resync/recovery/reshape
3532 	 *  - old personality can be suspended
3533 	 *  - new personality will access other array.
3534 	 */
3535 
3536 	if (mddev->sync_thread ||
3537 	    mddev->reshape_position != MaxSector ||
3538 	    mddev->sysfs_active)
3539 		return -EBUSY;
3540 
3541 	if (!mddev->pers->quiesce) {
3542 		printk(KERN_WARNING "md: %s: %s does not support online personality change\n",
3543 		       mdname(mddev), mddev->pers->name);
3544 		return -EINVAL;
3545 	}
3546 
3547 	/* Now find the new personality */
3548 	if (len == 0 || len >= sizeof(clevel))
3549 		return -EINVAL;
3550 	strncpy(clevel, buf, len);
3551 	if (clevel[len-1] == '\n')
3552 		len--;
3553 	clevel[len] = 0;
3554 	if (strict_strtol(clevel, 10, &level))
3555 		level = LEVEL_NONE;
3556 
3557 	if (request_module("md-%s", clevel) != 0)
3558 		request_module("md-level-%s", clevel);
3559 	spin_lock(&pers_lock);
3560 	pers = find_pers(level, clevel);
3561 	if (!pers || !try_module_get(pers->owner)) {
3562 		spin_unlock(&pers_lock);
3563 		printk(KERN_WARNING "md: personality %s not loaded\n", clevel);
3564 		return -EINVAL;
3565 	}
3566 	spin_unlock(&pers_lock);
3567 
3568 	if (pers == mddev->pers) {
3569 		/* Nothing to do! */
3570 		module_put(pers->owner);
3571 		return rv;
3572 	}
3573 	if (!pers->takeover) {
3574 		module_put(pers->owner);
3575 		printk(KERN_WARNING "md: %s: %s does not support personality takeover\n",
3576 		       mdname(mddev), clevel);
3577 		return -EINVAL;
3578 	}
3579 
3580 	rdev_for_each(rdev, mddev)
3581 		rdev->new_raid_disk = rdev->raid_disk;
3582 
3583 	/* ->takeover must set new_* and/or delta_disks
3584 	 * if it succeeds, and may set them when it fails.
3585 	 */
3586 	priv = pers->takeover(mddev);
3587 	if (IS_ERR(priv)) {
3588 		mddev->new_level = mddev->level;
3589 		mddev->new_layout = mddev->layout;
3590 		mddev->new_chunk_sectors = mddev->chunk_sectors;
3591 		mddev->raid_disks -= mddev->delta_disks;
3592 		mddev->delta_disks = 0;
3593 		mddev->reshape_backwards = 0;
3594 		module_put(pers->owner);
3595 		printk(KERN_WARNING "md: %s: %s would not accept array\n",
3596 		       mdname(mddev), clevel);
3597 		return PTR_ERR(priv);
3598 	}
3599 
3600 	/* Looks like we have a winner */
3601 	mddev_suspend(mddev);
3602 	mddev->pers->stop(mddev);
3603 
3604 	if (mddev->pers->sync_request == NULL &&
3605 	    pers->sync_request != NULL) {
3606 		/* need to add the md_redundancy_group */
3607 		if (sysfs_create_group(&mddev->kobj, &md_redundancy_group))
3608 			printk(KERN_WARNING
3609 			       "md: cannot register extra attributes for %s\n",
3610 			       mdname(mddev));
3611 		mddev->sysfs_action = sysfs_get_dirent(mddev->kobj.sd, NULL, "sync_action");
3612 	}
3613 	if (mddev->pers->sync_request != NULL &&
3614 	    pers->sync_request == NULL) {
3615 		/* need to remove the md_redundancy_group */
3616 		if (mddev->to_remove == NULL)
3617 			mddev->to_remove = &md_redundancy_group;
3618 	}
3619 
3620 	if (mddev->pers->sync_request == NULL &&
3621 	    mddev->external) {
3622 		/* We are converting from a no-redundancy array
3623 		 * to a redundancy array and metadata is managed
3624 		 * externally so we need to be sure that writes
3625 		 * won't block due to a need to transition
3626 		 *      clean->dirty
3627 		 * until external management is started.
3628 		 */
3629 		mddev->in_sync = 0;
3630 		mddev->safemode_delay = 0;
3631 		mddev->safemode = 0;
3632 	}
3633 
3634 	rdev_for_each(rdev, mddev) {
3635 		if (rdev->raid_disk < 0)
3636 			continue;
3637 		if (rdev->new_raid_disk >= mddev->raid_disks)
3638 			rdev->new_raid_disk = -1;
3639 		if (rdev->new_raid_disk == rdev->raid_disk)
3640 			continue;
3641 		sysfs_unlink_rdev(mddev, rdev);
3642 	}
3643 	rdev_for_each(rdev, mddev) {
3644 		if (rdev->raid_disk < 0)
3645 			continue;
3646 		if (rdev->new_raid_disk == rdev->raid_disk)
3647 			continue;
3648 		rdev->raid_disk = rdev->new_raid_disk;
3649 		if (rdev->raid_disk < 0)
3650 			clear_bit(In_sync, &rdev->flags);
3651 		else {
3652 			if (sysfs_link_rdev(mddev, rdev))
3653 				printk(KERN_WARNING "md: cannot register rd%d"
3654 				       " for %s after level change\n",
3655 				       rdev->raid_disk, mdname(mddev));
3656 		}
3657 	}
3658 
3659 	module_put(mddev->pers->owner);
3660 	mddev->pers = pers;
3661 	mddev->private = priv;
3662 	strlcpy(mddev->clevel, pers->name, sizeof(mddev->clevel));
3663 	mddev->level = mddev->new_level;
3664 	mddev->layout = mddev->new_layout;
3665 	mddev->chunk_sectors = mddev->new_chunk_sectors;
3666 	mddev->delta_disks = 0;
3667 	mddev->reshape_backwards = 0;
3668 	mddev->degraded = 0;
3669 	if (mddev->pers->sync_request == NULL) {
3670 		/* this is now an array without redundancy, so
3671 		 * it must always be in_sync
3672 		 */
3673 		mddev->in_sync = 1;
3674 		del_timer_sync(&mddev->safemode_timer);
3675 	}
3676 	pers->run(mddev);
3677 	set_bit(MD_CHANGE_DEVS, &mddev->flags);
3678 	mddev_resume(mddev);
3679 	sysfs_notify(&mddev->kobj, NULL, "level");
3680 	md_new_event(mddev);
3681 	return rv;
3682 }
3683 
3684 static struct md_sysfs_entry md_level =
3685 __ATTR(level, S_IRUGO|S_IWUSR, level_show, level_store);
3686 
3687 
3688 static ssize_t
3689 layout_show(struct mddev *mddev, char *page)
3690 {
3691 	/* just a number, not meaningful for all levels */
3692 	if (mddev->reshape_position != MaxSector &&
3693 	    mddev->layout != mddev->new_layout)
3694 		return sprintf(page, "%d (%d)\n",
3695 			       mddev->new_layout, mddev->layout);
3696 	return sprintf(page, "%d\n", mddev->layout);
3697 }
3698 
3699 static ssize_t
3700 layout_store(struct mddev *mddev, const char *buf, size_t len)
3701 {
3702 	char *e;
3703 	unsigned long n = simple_strtoul(buf, &e, 10);
3704 
3705 	if (!*buf || (*e && *e != '\n'))
3706 		return -EINVAL;
3707 
3708 	if (mddev->pers) {
3709 		int err;
3710 		if (mddev->pers->check_reshape == NULL)
3711 			return -EBUSY;
3712 		mddev->new_layout = n;
3713 		err = mddev->pers->check_reshape(mddev);
3714 		if (err) {
3715 			mddev->new_layout = mddev->layout;
3716 			return err;
3717 		}
3718 	} else {
3719 		mddev->new_layout = n;
3720 		if (mddev->reshape_position == MaxSector)
3721 			mddev->layout = n;
3722 	}
3723 	return len;
3724 }
3725 static struct md_sysfs_entry md_layout =
3726 __ATTR(layout, S_IRUGO|S_IWUSR, layout_show, layout_store);
3727 
3728 
3729 static ssize_t
3730 raid_disks_show(struct mddev *mddev, char *page)
3731 {
3732 	if (mddev->raid_disks == 0)
3733 		return 0;
3734 	if (mddev->reshape_position != MaxSector &&
3735 	    mddev->delta_disks != 0)
3736 		return sprintf(page, "%d (%d)\n", mddev->raid_disks,
3737 			       mddev->raid_disks - mddev->delta_disks);
3738 	return sprintf(page, "%d\n", mddev->raid_disks);
3739 }
3740 
3741 static int update_raid_disks(struct mddev *mddev, int raid_disks);
3742 
3743 static ssize_t
3744 raid_disks_store(struct mddev *mddev, const char *buf, size_t len)
3745 {
3746 	char *e;
3747 	int rv = 0;
3748 	unsigned long n = simple_strtoul(buf, &e, 10);
3749 
3750 	if (!*buf || (*e && *e != '\n'))
3751 		return -EINVAL;
3752 
3753 	if (mddev->pers)
3754 		rv = update_raid_disks(mddev, n);
3755 	else if (mddev->reshape_position != MaxSector) {
3756 		struct md_rdev *rdev;
3757 		int olddisks = mddev->raid_disks - mddev->delta_disks;
3758 
3759 		rdev_for_each(rdev, mddev) {
3760 			if (olddisks < n &&
3761 			    rdev->data_offset < rdev->new_data_offset)
3762 				return -EINVAL;
3763 			if (olddisks > n &&
3764 			    rdev->data_offset > rdev->new_data_offset)
3765 				return -EINVAL;
3766 		}
3767 		mddev->delta_disks = n - olddisks;
3768 		mddev->raid_disks = n;
3769 		mddev->reshape_backwards = (mddev->delta_disks < 0);
3770 	} else
3771 		mddev->raid_disks = n;
3772 	return rv ? rv : len;
3773 }
3774 static struct md_sysfs_entry md_raid_disks =
3775 __ATTR(raid_disks, S_IRUGO|S_IWUSR, raid_disks_show, raid_disks_store);
3776 
3777 static ssize_t
3778 chunk_size_show(struct mddev *mddev, char *page)
3779 {
3780 	if (mddev->reshape_position != MaxSector &&
3781 	    mddev->chunk_sectors != mddev->new_chunk_sectors)
3782 		return sprintf(page, "%d (%d)\n",
3783 			       mddev->new_chunk_sectors << 9,
3784 			       mddev->chunk_sectors << 9);
3785 	return sprintf(page, "%d\n", mddev->chunk_sectors << 9);
3786 }
3787 
3788 static ssize_t
3789 chunk_size_store(struct mddev *mddev, const char *buf, size_t len)
3790 {
3791 	char *e;
3792 	unsigned long n = simple_strtoul(buf, &e, 10);
3793 
3794 	if (!*buf || (*e && *e != '\n'))
3795 		return -EINVAL;
3796 
3797 	if (mddev->pers) {
3798 		int err;
3799 		if (mddev->pers->check_reshape == NULL)
3800 			return -EBUSY;
3801 		mddev->new_chunk_sectors = n >> 9;
3802 		err = mddev->pers->check_reshape(mddev);
3803 		if (err) {
3804 			mddev->new_chunk_sectors = mddev->chunk_sectors;
3805 			return err;
3806 		}
3807 	} else {
3808 		mddev->new_chunk_sectors = n >> 9;
3809 		if (mddev->reshape_position == MaxSector)
3810 			mddev->chunk_sectors = n >> 9;
3811 	}
3812 	return len;
3813 }
3814 static struct md_sysfs_entry md_chunk_size =
3815 __ATTR(chunk_size, S_IRUGO|S_IWUSR, chunk_size_show, chunk_size_store);
3816 
3817 static ssize_t
3818 resync_start_show(struct mddev *mddev, char *page)
3819 {
3820 	if (mddev->recovery_cp == MaxSector)
3821 		return sprintf(page, "none\n");
3822 	return sprintf(page, "%llu\n", (unsigned long long)mddev->recovery_cp);
3823 }
3824 
3825 static ssize_t
3826 resync_start_store(struct mddev *mddev, const char *buf, size_t len)
3827 {
3828 	char *e;
3829 	unsigned long long n = simple_strtoull(buf, &e, 10);
3830 
3831 	if (mddev->pers && !test_bit(MD_RECOVERY_FROZEN, &mddev->recovery))
3832 		return -EBUSY;
3833 	if (cmd_match(buf, "none"))
3834 		n = MaxSector;
3835 	else if (!*buf || (*e && *e != '\n'))
3836 		return -EINVAL;
3837 
3838 	mddev->recovery_cp = n;
3839 	return len;
3840 }
3841 static struct md_sysfs_entry md_resync_start =
3842 __ATTR(resync_start, S_IRUGO|S_IWUSR, resync_start_show, resync_start_store);
3843 
3844 /*
3845  * The array state can be:
3846  *
3847  * clear
3848  *     No devices, no size, no level
3849  *     Equivalent to STOP_ARRAY ioctl
3850  * inactive
3851  *     May have some settings, but array is not active
3852  *        all IO results in error
3853  *     When written, doesn't tear down array, but just stops it
3854  * suspended (not supported yet)
3855  *     All IO requests will block. The array can be reconfigured.
3856  *     Writing this, if accepted, will block until array is quiescent
3857  * readonly
3858  *     no resync can happen.  no superblocks get written.
3859  *     write requests fail
3860  * read-auto
3861  *     like readonly, but behaves like 'clean' on a write request.
3862  *
3863  * clean - no pending writes, but otherwise active.
3864  *     When written to inactive array, starts without resync
3865  *     If a write request arrives then
3866  *       if metadata is known, mark 'dirty' and switch to 'active'.
3867  *       if not known, block and switch to write-pending
3868  *     If written to an active array that has pending writes, then fails.
3869  * active
3870  *     fully active: IO and resync can be happening.
3871  *     When written to inactive array, starts with resync
3872  *
3873  * write-pending
3874  *     clean, but writes are blocked waiting for 'active' to be written.
3875  *
3876  * active-idle
3877  *     like active, but no writes have been seen for a while (100msec).
3878  *
3879  */
3880 enum array_state { clear, inactive, suspended, readonly, read_auto, clean, active,
3881 		   write_pending, active_idle, bad_word};
3882 static char *array_states[] = {
3883 	"clear", "inactive", "suspended", "readonly", "read-auto", "clean", "active",
3884 	"write-pending", "active-idle", NULL };
3885 
3886 static int match_word(const char *word, char **list)
3887 {
3888 	int n;
3889 	for (n=0; list[n]; n++)
3890 		if (cmd_match(word, list[n]))
3891 			break;
3892 	return n;
3893 }
3894 
3895 static ssize_t
3896 array_state_show(struct mddev *mddev, char *page)
3897 {
3898 	enum array_state st = inactive;
3899 
3900 	if (mddev->pers)
3901 		switch(mddev->ro) {
3902 		case 1:
3903 			st = readonly;
3904 			break;
3905 		case 2:
3906 			st = read_auto;
3907 			break;
3908 		case 0:
3909 			if (mddev->in_sync)
3910 				st = clean;
3911 			else if (test_bit(MD_CHANGE_PENDING, &mddev->flags))
3912 				st = write_pending;
3913 			else if (mddev->safemode)
3914 				st = active_idle;
3915 			else
3916 				st = active;
3917 		}
3918 	else {
3919 		if (list_empty(&mddev->disks) &&
3920 		    mddev->raid_disks == 0 &&
3921 		    mddev->dev_sectors == 0)
3922 			st = clear;
3923 		else
3924 			st = inactive;
3925 	}
3926 	return sprintf(page, "%s\n", array_states[st]);
3927 }
3928 
3929 static int do_md_stop(struct mddev * mddev, int ro, int is_open);
3930 static int md_set_readonly(struct mddev * mddev, int is_open);
3931 static int do_md_run(struct mddev * mddev);
3932 static int restart_array(struct mddev *mddev);
3933 
3934 static ssize_t
3935 array_state_store(struct mddev *mddev, const char *buf, size_t len)
3936 {
3937 	int err = -EINVAL;
3938 	enum array_state st = match_word(buf, array_states);
3939 	switch(st) {
3940 	case bad_word:
3941 		break;
3942 	case clear:
3943 		/* stopping an active array */
3944 		if (atomic_read(&mddev->openers) > 0)
3945 			return -EBUSY;
3946 		err = do_md_stop(mddev, 0, 0);
3947 		break;
3948 	case inactive:
3949 		/* stopping an active array */
3950 		if (mddev->pers) {
3951 			if (atomic_read(&mddev->openers) > 0)
3952 				return -EBUSY;
3953 			err = do_md_stop(mddev, 2, 0);
3954 		} else
3955 			err = 0; /* already inactive */
3956 		break;
3957 	case suspended:
3958 		break; /* not supported yet */
3959 	case readonly:
3960 		if (mddev->pers)
3961 			err = md_set_readonly(mddev, 0);
3962 		else {
3963 			mddev->ro = 1;
3964 			set_disk_ro(mddev->gendisk, 1);
3965 			err = do_md_run(mddev);
3966 		}
3967 		break;
3968 	case read_auto:
3969 		if (mddev->pers) {
3970 			if (mddev->ro == 0)
3971 				err = md_set_readonly(mddev, 0);
3972 			else if (mddev->ro == 1)
3973 				err = restart_array(mddev);
3974 			if (err == 0) {
3975 				mddev->ro = 2;
3976 				set_disk_ro(mddev->gendisk, 0);
3977 			}
3978 		} else {
3979 			mddev->ro = 2;
3980 			err = do_md_run(mddev);
3981 		}
3982 		break;
3983 	case clean:
3984 		if (mddev->pers) {
3985 			restart_array(mddev);
3986 			spin_lock_irq(&mddev->write_lock);
3987 			if (atomic_read(&mddev->writes_pending) == 0) {
3988 				if (mddev->in_sync == 0) {
3989 					mddev->in_sync = 1;
3990 					if (mddev->safemode == 1)
3991 						mddev->safemode = 0;
3992 					set_bit(MD_CHANGE_CLEAN, &mddev->flags);
3993 				}
3994 				err = 0;
3995 			} else
3996 				err = -EBUSY;
3997 			spin_unlock_irq(&mddev->write_lock);
3998 		} else
3999 			err = -EINVAL;
4000 		break;
4001 	case active:
4002 		if (mddev->pers) {
4003 			restart_array(mddev);
4004 			clear_bit(MD_CHANGE_PENDING, &mddev->flags);
4005 			wake_up(&mddev->sb_wait);
4006 			err = 0;
4007 		} else {
4008 			mddev->ro = 0;
4009 			set_disk_ro(mddev->gendisk, 0);
4010 			err = do_md_run(mddev);
4011 		}
4012 		break;
4013 	case write_pending:
4014 	case active_idle:
4015 		/* these cannot be set */
4016 		break;
4017 	}
4018 	if (err)
4019 		return err;
4020 	else {
4021 		if (mddev->hold_active == UNTIL_IOCTL)
4022 			mddev->hold_active = 0;
4023 		sysfs_notify_dirent_safe(mddev->sysfs_state);
4024 		return len;
4025 	}
4026 }
4027 static struct md_sysfs_entry md_array_state =
4028 __ATTR(array_state, S_IRUGO|S_IWUSR, array_state_show, array_state_store);
4029 
4030 static ssize_t
4031 max_corrected_read_errors_show(struct mddev *mddev, char *page) {
4032 	return sprintf(page, "%d\n",
4033 		       atomic_read(&mddev->max_corr_read_errors));
4034 }
4035 
4036 static ssize_t
4037 max_corrected_read_errors_store(struct mddev *mddev, const char *buf, size_t len)
4038 {
4039 	char *e;
4040 	unsigned long n = simple_strtoul(buf, &e, 10);
4041 
4042 	if (*buf && (*e == 0 || *e == '\n')) {
4043 		atomic_set(&mddev->max_corr_read_errors, n);
4044 		return len;
4045 	}
4046 	return -EINVAL;
4047 }
4048 
4049 static struct md_sysfs_entry max_corr_read_errors =
4050 __ATTR(max_read_errors, S_IRUGO|S_IWUSR, max_corrected_read_errors_show,
4051 	max_corrected_read_errors_store);
4052 
4053 static ssize_t
4054 null_show(struct mddev *mddev, char *page)
4055 {
4056 	return -EINVAL;
4057 }
4058 
4059 static ssize_t
4060 new_dev_store(struct mddev *mddev, const char *buf, size_t len)
4061 {
4062 	/* buf must be %d:%d\n? giving major and minor numbers */
4063 	/* The new device is added to the array.
4064 	 * If the array has a persistent superblock, we read the
4065 	 * superblock to initialise info and check validity.
4066 	 * Otherwise, only checking done is that in bind_rdev_to_array,
4067 	 * which mainly checks size.
4068 	 */
4069 	char *e;
4070 	int major = simple_strtoul(buf, &e, 10);
4071 	int minor;
4072 	dev_t dev;
4073 	struct md_rdev *rdev;
4074 	int err;
4075 
4076 	if (!*buf || *e != ':' || !e[1] || e[1] == '\n')
4077 		return -EINVAL;
4078 	minor = simple_strtoul(e+1, &e, 10);
4079 	if (*e && *e != '\n')
4080 		return -EINVAL;
4081 	dev = MKDEV(major, minor);
4082 	if (major != MAJOR(dev) ||
4083 	    minor != MINOR(dev))
4084 		return -EOVERFLOW;
4085 
4086 
4087 	if (mddev->persistent) {
4088 		rdev = md_import_device(dev, mddev->major_version,
4089 					mddev->minor_version);
4090 		if (!IS_ERR(rdev) && !list_empty(&mddev->disks)) {
4091 			struct md_rdev *rdev0
4092 				= list_entry(mddev->disks.next,
4093 					     struct md_rdev, same_set);
4094 			err = super_types[mddev->major_version]
4095 				.load_super(rdev, rdev0, mddev->minor_version);
4096 			if (err < 0)
4097 				goto out;
4098 		}
4099 	} else if (mddev->external)
4100 		rdev = md_import_device(dev, -2, -1);
4101 	else
4102 		rdev = md_import_device(dev, -1, -1);
4103 
4104 	if (IS_ERR(rdev))
4105 		return PTR_ERR(rdev);
4106 	err = bind_rdev_to_array(rdev, mddev);
4107  out:
4108 	if (err)
4109 		export_rdev(rdev);
4110 	return err ? err : len;
4111 }
4112 
4113 static struct md_sysfs_entry md_new_device =
4114 __ATTR(new_dev, S_IWUSR, null_show, new_dev_store);
4115 
4116 static ssize_t
4117 bitmap_store(struct mddev *mddev, const char *buf, size_t len)
4118 {
4119 	char *end;
4120 	unsigned long chunk, end_chunk;
4121 
4122 	if (!mddev->bitmap)
4123 		goto out;
4124 	/* buf should be <chunk> <chunk> ... or <chunk>-<chunk> ... (range) */
4125 	while (*buf) {
4126 		chunk = end_chunk = simple_strtoul(buf, &end, 0);
4127 		if (buf == end) break;
4128 		if (*end == '-') { /* range */
4129 			buf = end + 1;
4130 			end_chunk = simple_strtoul(buf, &end, 0);
4131 			if (buf == end) break;
4132 		}
4133 		if (*end && !isspace(*end)) break;
4134 		bitmap_dirty_bits(mddev->bitmap, chunk, end_chunk);
4135 		buf = skip_spaces(end);
4136 	}
4137 	bitmap_unplug(mddev->bitmap); /* flush the bits to disk */
4138 out:
4139 	return len;
4140 }
4141 
4142 static struct md_sysfs_entry md_bitmap =
4143 __ATTR(bitmap_set_bits, S_IWUSR, null_show, bitmap_store);
4144 
4145 static ssize_t
4146 size_show(struct mddev *mddev, char *page)
4147 {
4148 	return sprintf(page, "%llu\n",
4149 		(unsigned long long)mddev->dev_sectors / 2);
4150 }
4151 
4152 static int update_size(struct mddev *mddev, sector_t num_sectors);
4153 
4154 static ssize_t
4155 size_store(struct mddev *mddev, const char *buf, size_t len)
4156 {
4157 	/* If array is inactive, we can reduce the component size, but
4158 	 * not increase it (except from 0).
4159 	 * If array is active, we can try an on-line resize
4160 	 */
4161 	sector_t sectors;
4162 	int err = strict_blocks_to_sectors(buf, &sectors);
4163 
4164 	if (err < 0)
4165 		return err;
4166 	if (mddev->pers) {
4167 		err = update_size(mddev, sectors);
4168 		md_update_sb(mddev, 1);
4169 	} else {
4170 		if (mddev->dev_sectors == 0 ||
4171 		    mddev->dev_sectors > sectors)
4172 			mddev->dev_sectors = sectors;
4173 		else
4174 			err = -ENOSPC;
4175 	}
4176 	return err ? err : len;
4177 }
4178 
4179 static struct md_sysfs_entry md_size =
4180 __ATTR(component_size, S_IRUGO|S_IWUSR, size_show, size_store);
4181 
4182 
4183 /* Metdata version.
4184  * This is one of
4185  *   'none' for arrays with no metadata (good luck...)
4186  *   'external' for arrays with externally managed metadata,
4187  * or N.M for internally known formats
4188  */
4189 static ssize_t
4190 metadata_show(struct mddev *mddev, char *page)
4191 {
4192 	if (mddev->persistent)
4193 		return sprintf(page, "%d.%d\n",
4194 			       mddev->major_version, mddev->minor_version);
4195 	else if (mddev->external)
4196 		return sprintf(page, "external:%s\n", mddev->metadata_type);
4197 	else
4198 		return sprintf(page, "none\n");
4199 }
4200 
4201 static ssize_t
4202 metadata_store(struct mddev *mddev, const char *buf, size_t len)
4203 {
4204 	int major, minor;
4205 	char *e;
4206 	/* Changing the details of 'external' metadata is
4207 	 * always permitted.  Otherwise there must be
4208 	 * no devices attached to the array.
4209 	 */
4210 	if (mddev->external && strncmp(buf, "external:", 9) == 0)
4211 		;
4212 	else if (!list_empty(&mddev->disks))
4213 		return -EBUSY;
4214 
4215 	if (cmd_match(buf, "none")) {
4216 		mddev->persistent = 0;
4217 		mddev->external = 0;
4218 		mddev->major_version = 0;
4219 		mddev->minor_version = 90;
4220 		return len;
4221 	}
4222 	if (strncmp(buf, "external:", 9) == 0) {
4223 		size_t namelen = len-9;
4224 		if (namelen >= sizeof(mddev->metadata_type))
4225 			namelen = sizeof(mddev->metadata_type)-1;
4226 		strncpy(mddev->metadata_type, buf+9, namelen);
4227 		mddev->metadata_type[namelen] = 0;
4228 		if (namelen && mddev->metadata_type[namelen-1] == '\n')
4229 			mddev->metadata_type[--namelen] = 0;
4230 		mddev->persistent = 0;
4231 		mddev->external = 1;
4232 		mddev->major_version = 0;
4233 		mddev->minor_version = 90;
4234 		return len;
4235 	}
4236 	major = simple_strtoul(buf, &e, 10);
4237 	if (e==buf || *e != '.')
4238 		return -EINVAL;
4239 	buf = e+1;
4240 	minor = simple_strtoul(buf, &e, 10);
4241 	if (e==buf || (*e && *e != '\n') )
4242 		return -EINVAL;
4243 	if (major >= ARRAY_SIZE(super_types) || super_types[major].name == NULL)
4244 		return -ENOENT;
4245 	mddev->major_version = major;
4246 	mddev->minor_version = minor;
4247 	mddev->persistent = 1;
4248 	mddev->external = 0;
4249 	return len;
4250 }
4251 
4252 static struct md_sysfs_entry md_metadata =
4253 __ATTR(metadata_version, S_IRUGO|S_IWUSR, metadata_show, metadata_store);
4254 
4255 static ssize_t
4256 action_show(struct mddev *mddev, char *page)
4257 {
4258 	char *type = "idle";
4259 	if (test_bit(MD_RECOVERY_FROZEN, &mddev->recovery))
4260 		type = "frozen";
4261 	else if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
4262 	    (!mddev->ro && test_bit(MD_RECOVERY_NEEDED, &mddev->recovery))) {
4263 		if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
4264 			type = "reshape";
4265 		else if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
4266 			if (!test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
4267 				type = "resync";
4268 			else if (test_bit(MD_RECOVERY_CHECK, &mddev->recovery))
4269 				type = "check";
4270 			else
4271 				type = "repair";
4272 		} else if (test_bit(MD_RECOVERY_RECOVER, &mddev->recovery))
4273 			type = "recover";
4274 	}
4275 	return sprintf(page, "%s\n", type);
4276 }
4277 
4278 static void reap_sync_thread(struct mddev *mddev);
4279 
4280 static ssize_t
4281 action_store(struct mddev *mddev, const char *page, size_t len)
4282 {
4283 	if (!mddev->pers || !mddev->pers->sync_request)
4284 		return -EINVAL;
4285 
4286 	if (cmd_match(page, "frozen"))
4287 		set_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
4288 	else
4289 		clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
4290 
4291 	if (cmd_match(page, "idle") || cmd_match(page, "frozen")) {
4292 		if (mddev->sync_thread) {
4293 			set_bit(MD_RECOVERY_INTR, &mddev->recovery);
4294 			reap_sync_thread(mddev);
4295 		}
4296 	} else if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
4297 		   test_bit(MD_RECOVERY_NEEDED, &mddev->recovery))
4298 		return -EBUSY;
4299 	else if (cmd_match(page, "resync"))
4300 		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
4301 	else if (cmd_match(page, "recover")) {
4302 		set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
4303 		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
4304 	} else if (cmd_match(page, "reshape")) {
4305 		int err;
4306 		if (mddev->pers->start_reshape == NULL)
4307 			return -EINVAL;
4308 		err = mddev->pers->start_reshape(mddev);
4309 		if (err)
4310 			return err;
4311 		sysfs_notify(&mddev->kobj, NULL, "degraded");
4312 	} else {
4313 		if (cmd_match(page, "check"))
4314 			set_bit(MD_RECOVERY_CHECK, &mddev->recovery);
4315 		else if (!cmd_match(page, "repair"))
4316 			return -EINVAL;
4317 		set_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
4318 		set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
4319 	}
4320 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
4321 	md_wakeup_thread(mddev->thread);
4322 	sysfs_notify_dirent_safe(mddev->sysfs_action);
4323 	return len;
4324 }
4325 
4326 static ssize_t
4327 mismatch_cnt_show(struct mddev *mddev, char *page)
4328 {
4329 	return sprintf(page, "%llu\n",
4330 		       (unsigned long long) mddev->resync_mismatches);
4331 }
4332 
4333 static struct md_sysfs_entry md_scan_mode =
4334 __ATTR(sync_action, S_IRUGO|S_IWUSR, action_show, action_store);
4335 
4336 
4337 static struct md_sysfs_entry md_mismatches = __ATTR_RO(mismatch_cnt);
4338 
4339 static ssize_t
4340 sync_min_show(struct mddev *mddev, char *page)
4341 {
4342 	return sprintf(page, "%d (%s)\n", speed_min(mddev),
4343 		       mddev->sync_speed_min ? "local": "system");
4344 }
4345 
4346 static ssize_t
4347 sync_min_store(struct mddev *mddev, const char *buf, size_t len)
4348 {
4349 	int min;
4350 	char *e;
4351 	if (strncmp(buf, "system", 6)==0) {
4352 		mddev->sync_speed_min = 0;
4353 		return len;
4354 	}
4355 	min = simple_strtoul(buf, &e, 10);
4356 	if (buf == e || (*e && *e != '\n') || min <= 0)
4357 		return -EINVAL;
4358 	mddev->sync_speed_min = min;
4359 	return len;
4360 }
4361 
4362 static struct md_sysfs_entry md_sync_min =
4363 __ATTR(sync_speed_min, S_IRUGO|S_IWUSR, sync_min_show, sync_min_store);
4364 
4365 static ssize_t
4366 sync_max_show(struct mddev *mddev, char *page)
4367 {
4368 	return sprintf(page, "%d (%s)\n", speed_max(mddev),
4369 		       mddev->sync_speed_max ? "local": "system");
4370 }
4371 
4372 static ssize_t
4373 sync_max_store(struct mddev *mddev, const char *buf, size_t len)
4374 {
4375 	int max;
4376 	char *e;
4377 	if (strncmp(buf, "system", 6)==0) {
4378 		mddev->sync_speed_max = 0;
4379 		return len;
4380 	}
4381 	max = simple_strtoul(buf, &e, 10);
4382 	if (buf == e || (*e && *e != '\n') || max <= 0)
4383 		return -EINVAL;
4384 	mddev->sync_speed_max = max;
4385 	return len;
4386 }
4387 
4388 static struct md_sysfs_entry md_sync_max =
4389 __ATTR(sync_speed_max, S_IRUGO|S_IWUSR, sync_max_show, sync_max_store);
4390 
4391 static ssize_t
4392 degraded_show(struct mddev *mddev, char *page)
4393 {
4394 	return sprintf(page, "%d\n", mddev->degraded);
4395 }
4396 static struct md_sysfs_entry md_degraded = __ATTR_RO(degraded);
4397 
4398 static ssize_t
4399 sync_force_parallel_show(struct mddev *mddev, char *page)
4400 {
4401 	return sprintf(page, "%d\n", mddev->parallel_resync);
4402 }
4403 
4404 static ssize_t
4405 sync_force_parallel_store(struct mddev *mddev, const char *buf, size_t len)
4406 {
4407 	long n;
4408 
4409 	if (strict_strtol(buf, 10, &n))
4410 		return -EINVAL;
4411 
4412 	if (n != 0 && n != 1)
4413 		return -EINVAL;
4414 
4415 	mddev->parallel_resync = n;
4416 
4417 	if (mddev->sync_thread)
4418 		wake_up(&resync_wait);
4419 
4420 	return len;
4421 }
4422 
4423 /* force parallel resync, even with shared block devices */
4424 static struct md_sysfs_entry md_sync_force_parallel =
4425 __ATTR(sync_force_parallel, S_IRUGO|S_IWUSR,
4426        sync_force_parallel_show, sync_force_parallel_store);
4427 
4428 static ssize_t
4429 sync_speed_show(struct mddev *mddev, char *page)
4430 {
4431 	unsigned long resync, dt, db;
4432 	if (mddev->curr_resync == 0)
4433 		return sprintf(page, "none\n");
4434 	resync = mddev->curr_mark_cnt - atomic_read(&mddev->recovery_active);
4435 	dt = (jiffies - mddev->resync_mark) / HZ;
4436 	if (!dt) dt++;
4437 	db = resync - mddev->resync_mark_cnt;
4438 	return sprintf(page, "%lu\n", db/dt/2); /* K/sec */
4439 }
4440 
4441 static struct md_sysfs_entry md_sync_speed = __ATTR_RO(sync_speed);
4442 
4443 static ssize_t
4444 sync_completed_show(struct mddev *mddev, char *page)
4445 {
4446 	unsigned long long max_sectors, resync;
4447 
4448 	if (!test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
4449 		return sprintf(page, "none\n");
4450 
4451 	if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) ||
4452 	    test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
4453 		max_sectors = mddev->resync_max_sectors;
4454 	else
4455 		max_sectors = mddev->dev_sectors;
4456 
4457 	resync = mddev->curr_resync_completed;
4458 	return sprintf(page, "%llu / %llu\n", resync, max_sectors);
4459 }
4460 
4461 static struct md_sysfs_entry md_sync_completed = __ATTR_RO(sync_completed);
4462 
4463 static ssize_t
4464 min_sync_show(struct mddev *mddev, char *page)
4465 {
4466 	return sprintf(page, "%llu\n",
4467 		       (unsigned long long)mddev->resync_min);
4468 }
4469 static ssize_t
4470 min_sync_store(struct mddev *mddev, const char *buf, size_t len)
4471 {
4472 	unsigned long long min;
4473 	if (strict_strtoull(buf, 10, &min))
4474 		return -EINVAL;
4475 	if (min > mddev->resync_max)
4476 		return -EINVAL;
4477 	if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
4478 		return -EBUSY;
4479 
4480 	/* Must be a multiple of chunk_size */
4481 	if (mddev->chunk_sectors) {
4482 		sector_t temp = min;
4483 		if (sector_div(temp, mddev->chunk_sectors))
4484 			return -EINVAL;
4485 	}
4486 	mddev->resync_min = min;
4487 
4488 	return len;
4489 }
4490 
4491 static struct md_sysfs_entry md_min_sync =
4492 __ATTR(sync_min, S_IRUGO|S_IWUSR, min_sync_show, min_sync_store);
4493 
4494 static ssize_t
4495 max_sync_show(struct mddev *mddev, char *page)
4496 {
4497 	if (mddev->resync_max == MaxSector)
4498 		return sprintf(page, "max\n");
4499 	else
4500 		return sprintf(page, "%llu\n",
4501 			       (unsigned long long)mddev->resync_max);
4502 }
4503 static ssize_t
4504 max_sync_store(struct mddev *mddev, const char *buf, size_t len)
4505 {
4506 	if (strncmp(buf, "max", 3) == 0)
4507 		mddev->resync_max = MaxSector;
4508 	else {
4509 		unsigned long long max;
4510 		if (strict_strtoull(buf, 10, &max))
4511 			return -EINVAL;
4512 		if (max < mddev->resync_min)
4513 			return -EINVAL;
4514 		if (max < mddev->resync_max &&
4515 		    mddev->ro == 0 &&
4516 		    test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
4517 			return -EBUSY;
4518 
4519 		/* Must be a multiple of chunk_size */
4520 		if (mddev->chunk_sectors) {
4521 			sector_t temp = max;
4522 			if (sector_div(temp, mddev->chunk_sectors))
4523 				return -EINVAL;
4524 		}
4525 		mddev->resync_max = max;
4526 	}
4527 	wake_up(&mddev->recovery_wait);
4528 	return len;
4529 }
4530 
4531 static struct md_sysfs_entry md_max_sync =
4532 __ATTR(sync_max, S_IRUGO|S_IWUSR, max_sync_show, max_sync_store);
4533 
4534 static ssize_t
4535 suspend_lo_show(struct mddev *mddev, char *page)
4536 {
4537 	return sprintf(page, "%llu\n", (unsigned long long)mddev->suspend_lo);
4538 }
4539 
4540 static ssize_t
4541 suspend_lo_store(struct mddev *mddev, const char *buf, size_t len)
4542 {
4543 	char *e;
4544 	unsigned long long new = simple_strtoull(buf, &e, 10);
4545 	unsigned long long old = mddev->suspend_lo;
4546 
4547 	if (mddev->pers == NULL ||
4548 	    mddev->pers->quiesce == NULL)
4549 		return -EINVAL;
4550 	if (buf == e || (*e && *e != '\n'))
4551 		return -EINVAL;
4552 
4553 	mddev->suspend_lo = new;
4554 	if (new >= old)
4555 		/* Shrinking suspended region */
4556 		mddev->pers->quiesce(mddev, 2);
4557 	else {
4558 		/* Expanding suspended region - need to wait */
4559 		mddev->pers->quiesce(mddev, 1);
4560 		mddev->pers->quiesce(mddev, 0);
4561 	}
4562 	return len;
4563 }
4564 static struct md_sysfs_entry md_suspend_lo =
4565 __ATTR(suspend_lo, S_IRUGO|S_IWUSR, suspend_lo_show, suspend_lo_store);
4566 
4567 
4568 static ssize_t
4569 suspend_hi_show(struct mddev *mddev, char *page)
4570 {
4571 	return sprintf(page, "%llu\n", (unsigned long long)mddev->suspend_hi);
4572 }
4573 
4574 static ssize_t
4575 suspend_hi_store(struct mddev *mddev, const char *buf, size_t len)
4576 {
4577 	char *e;
4578 	unsigned long long new = simple_strtoull(buf, &e, 10);
4579 	unsigned long long old = mddev->suspend_hi;
4580 
4581 	if (mddev->pers == NULL ||
4582 	    mddev->pers->quiesce == NULL)
4583 		return -EINVAL;
4584 	if (buf == e || (*e && *e != '\n'))
4585 		return -EINVAL;
4586 
4587 	mddev->suspend_hi = new;
4588 	if (new <= old)
4589 		/* Shrinking suspended region */
4590 		mddev->pers->quiesce(mddev, 2);
4591 	else {
4592 		/* Expanding suspended region - need to wait */
4593 		mddev->pers->quiesce(mddev, 1);
4594 		mddev->pers->quiesce(mddev, 0);
4595 	}
4596 	return len;
4597 }
4598 static struct md_sysfs_entry md_suspend_hi =
4599 __ATTR(suspend_hi, S_IRUGO|S_IWUSR, suspend_hi_show, suspend_hi_store);
4600 
4601 static ssize_t
4602 reshape_position_show(struct mddev *mddev, char *page)
4603 {
4604 	if (mddev->reshape_position != MaxSector)
4605 		return sprintf(page, "%llu\n",
4606 			       (unsigned long long)mddev->reshape_position);
4607 	strcpy(page, "none\n");
4608 	return 5;
4609 }
4610 
4611 static ssize_t
4612 reshape_position_store(struct mddev *mddev, const char *buf, size_t len)
4613 {
4614 	struct md_rdev *rdev;
4615 	char *e;
4616 	unsigned long long new = simple_strtoull(buf, &e, 10);
4617 	if (mddev->pers)
4618 		return -EBUSY;
4619 	if (buf == e || (*e && *e != '\n'))
4620 		return -EINVAL;
4621 	mddev->reshape_position = new;
4622 	mddev->delta_disks = 0;
4623 	mddev->reshape_backwards = 0;
4624 	mddev->new_level = mddev->level;
4625 	mddev->new_layout = mddev->layout;
4626 	mddev->new_chunk_sectors = mddev->chunk_sectors;
4627 	rdev_for_each(rdev, mddev)
4628 		rdev->new_data_offset = rdev->data_offset;
4629 	return len;
4630 }
4631 
4632 static struct md_sysfs_entry md_reshape_position =
4633 __ATTR(reshape_position, S_IRUGO|S_IWUSR, reshape_position_show,
4634        reshape_position_store);
4635 
4636 static ssize_t
4637 reshape_direction_show(struct mddev *mddev, char *page)
4638 {
4639 	return sprintf(page, "%s\n",
4640 		       mddev->reshape_backwards ? "backwards" : "forwards");
4641 }
4642 
4643 static ssize_t
4644 reshape_direction_store(struct mddev *mddev, const char *buf, size_t len)
4645 {
4646 	int backwards = 0;
4647 	if (cmd_match(buf, "forwards"))
4648 		backwards = 0;
4649 	else if (cmd_match(buf, "backwards"))
4650 		backwards = 1;
4651 	else
4652 		return -EINVAL;
4653 	if (mddev->reshape_backwards == backwards)
4654 		return len;
4655 
4656 	/* check if we are allowed to change */
4657 	if (mddev->delta_disks)
4658 		return -EBUSY;
4659 
4660 	if (mddev->persistent &&
4661 	    mddev->major_version == 0)
4662 		return -EINVAL;
4663 
4664 	mddev->reshape_backwards = backwards;
4665 	return len;
4666 }
4667 
4668 static struct md_sysfs_entry md_reshape_direction =
4669 __ATTR(reshape_direction, S_IRUGO|S_IWUSR, reshape_direction_show,
4670        reshape_direction_store);
4671 
4672 static ssize_t
4673 array_size_show(struct mddev *mddev, char *page)
4674 {
4675 	if (mddev->external_size)
4676 		return sprintf(page, "%llu\n",
4677 			       (unsigned long long)mddev->array_sectors/2);
4678 	else
4679 		return sprintf(page, "default\n");
4680 }
4681 
4682 static ssize_t
4683 array_size_store(struct mddev *mddev, const char *buf, size_t len)
4684 {
4685 	sector_t sectors;
4686 
4687 	if (strncmp(buf, "default", 7) == 0) {
4688 		if (mddev->pers)
4689 			sectors = mddev->pers->size(mddev, 0, 0);
4690 		else
4691 			sectors = mddev->array_sectors;
4692 
4693 		mddev->external_size = 0;
4694 	} else {
4695 		if (strict_blocks_to_sectors(buf, &sectors) < 0)
4696 			return -EINVAL;
4697 		if (mddev->pers && mddev->pers->size(mddev, 0, 0) < sectors)
4698 			return -E2BIG;
4699 
4700 		mddev->external_size = 1;
4701 	}
4702 
4703 	mddev->array_sectors = sectors;
4704 	if (mddev->pers) {
4705 		set_capacity(mddev->gendisk, mddev->array_sectors);
4706 		revalidate_disk(mddev->gendisk);
4707 	}
4708 	return len;
4709 }
4710 
4711 static struct md_sysfs_entry md_array_size =
4712 __ATTR(array_size, S_IRUGO|S_IWUSR, array_size_show,
4713        array_size_store);
4714 
4715 static struct attribute *md_default_attrs[] = {
4716 	&md_level.attr,
4717 	&md_layout.attr,
4718 	&md_raid_disks.attr,
4719 	&md_chunk_size.attr,
4720 	&md_size.attr,
4721 	&md_resync_start.attr,
4722 	&md_metadata.attr,
4723 	&md_new_device.attr,
4724 	&md_safe_delay.attr,
4725 	&md_array_state.attr,
4726 	&md_reshape_position.attr,
4727 	&md_reshape_direction.attr,
4728 	&md_array_size.attr,
4729 	&max_corr_read_errors.attr,
4730 	NULL,
4731 };
4732 
4733 static struct attribute *md_redundancy_attrs[] = {
4734 	&md_scan_mode.attr,
4735 	&md_mismatches.attr,
4736 	&md_sync_min.attr,
4737 	&md_sync_max.attr,
4738 	&md_sync_speed.attr,
4739 	&md_sync_force_parallel.attr,
4740 	&md_sync_completed.attr,
4741 	&md_min_sync.attr,
4742 	&md_max_sync.attr,
4743 	&md_suspend_lo.attr,
4744 	&md_suspend_hi.attr,
4745 	&md_bitmap.attr,
4746 	&md_degraded.attr,
4747 	NULL,
4748 };
4749 static struct attribute_group md_redundancy_group = {
4750 	.name = NULL,
4751 	.attrs = md_redundancy_attrs,
4752 };
4753 
4754 
4755 static ssize_t
4756 md_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
4757 {
4758 	struct md_sysfs_entry *entry = container_of(attr, struct md_sysfs_entry, attr);
4759 	struct mddev *mddev = container_of(kobj, struct mddev, kobj);
4760 	ssize_t rv;
4761 
4762 	if (!entry->show)
4763 		return -EIO;
4764 	spin_lock(&all_mddevs_lock);
4765 	if (list_empty(&mddev->all_mddevs)) {
4766 		spin_unlock(&all_mddevs_lock);
4767 		return -EBUSY;
4768 	}
4769 	mddev_get(mddev);
4770 	spin_unlock(&all_mddevs_lock);
4771 
4772 	rv = mddev_lock(mddev);
4773 	if (!rv) {
4774 		rv = entry->show(mddev, page);
4775 		mddev_unlock(mddev);
4776 	}
4777 	mddev_put(mddev);
4778 	return rv;
4779 }
4780 
4781 static ssize_t
4782 md_attr_store(struct kobject *kobj, struct attribute *attr,
4783 	      const char *page, size_t length)
4784 {
4785 	struct md_sysfs_entry *entry = container_of(attr, struct md_sysfs_entry, attr);
4786 	struct mddev *mddev = container_of(kobj, struct mddev, kobj);
4787 	ssize_t rv;
4788 
4789 	if (!entry->store)
4790 		return -EIO;
4791 	if (!capable(CAP_SYS_ADMIN))
4792 		return -EACCES;
4793 	spin_lock(&all_mddevs_lock);
4794 	if (list_empty(&mddev->all_mddevs)) {
4795 		spin_unlock(&all_mddevs_lock);
4796 		return -EBUSY;
4797 	}
4798 	mddev_get(mddev);
4799 	spin_unlock(&all_mddevs_lock);
4800 	rv = mddev_lock(mddev);
4801 	if (!rv) {
4802 		rv = entry->store(mddev, page, length);
4803 		mddev_unlock(mddev);
4804 	}
4805 	mddev_put(mddev);
4806 	return rv;
4807 }
4808 
4809 static void md_free(struct kobject *ko)
4810 {
4811 	struct mddev *mddev = container_of(ko, struct mddev, kobj);
4812 
4813 	if (mddev->sysfs_state)
4814 		sysfs_put(mddev->sysfs_state);
4815 
4816 	if (mddev->gendisk) {
4817 		del_gendisk(mddev->gendisk);
4818 		put_disk(mddev->gendisk);
4819 	}
4820 	if (mddev->queue)
4821 		blk_cleanup_queue(mddev->queue);
4822 
4823 	kfree(mddev);
4824 }
4825 
4826 static const struct sysfs_ops md_sysfs_ops = {
4827 	.show	= md_attr_show,
4828 	.store	= md_attr_store,
4829 };
4830 static struct kobj_type md_ktype = {
4831 	.release	= md_free,
4832 	.sysfs_ops	= &md_sysfs_ops,
4833 	.default_attrs	= md_default_attrs,
4834 };
4835 
4836 int mdp_major = 0;
4837 
4838 static void mddev_delayed_delete(struct work_struct *ws)
4839 {
4840 	struct mddev *mddev = container_of(ws, struct mddev, del_work);
4841 
4842 	sysfs_remove_group(&mddev->kobj, &md_bitmap_group);
4843 	kobject_del(&mddev->kobj);
4844 	kobject_put(&mddev->kobj);
4845 }
4846 
4847 static int md_alloc(dev_t dev, char *name)
4848 {
4849 	static DEFINE_MUTEX(disks_mutex);
4850 	struct mddev *mddev = mddev_find(dev);
4851 	struct gendisk *disk;
4852 	int partitioned;
4853 	int shift;
4854 	int unit;
4855 	int error;
4856 
4857 	if (!mddev)
4858 		return -ENODEV;
4859 
4860 	partitioned = (MAJOR(mddev->unit) != MD_MAJOR);
4861 	shift = partitioned ? MdpMinorShift : 0;
4862 	unit = MINOR(mddev->unit) >> shift;
4863 
4864 	/* wait for any previous instance of this device to be
4865 	 * completely removed (mddev_delayed_delete).
4866 	 */
4867 	flush_workqueue(md_misc_wq);
4868 
4869 	mutex_lock(&disks_mutex);
4870 	error = -EEXIST;
4871 	if (mddev->gendisk)
4872 		goto abort;
4873 
4874 	if (name) {
4875 		/* Need to ensure that 'name' is not a duplicate.
4876 		 */
4877 		struct mddev *mddev2;
4878 		spin_lock(&all_mddevs_lock);
4879 
4880 		list_for_each_entry(mddev2, &all_mddevs, all_mddevs)
4881 			if (mddev2->gendisk &&
4882 			    strcmp(mddev2->gendisk->disk_name, name) == 0) {
4883 				spin_unlock(&all_mddevs_lock);
4884 				goto abort;
4885 			}
4886 		spin_unlock(&all_mddevs_lock);
4887 	}
4888 
4889 	error = -ENOMEM;
4890 	mddev->queue = blk_alloc_queue(GFP_KERNEL);
4891 	if (!mddev->queue)
4892 		goto abort;
4893 	mddev->queue->queuedata = mddev;
4894 
4895 	blk_queue_make_request(mddev->queue, md_make_request);
4896 	blk_set_stacking_limits(&mddev->queue->limits);
4897 
4898 	disk = alloc_disk(1 << shift);
4899 	if (!disk) {
4900 		blk_cleanup_queue(mddev->queue);
4901 		mddev->queue = NULL;
4902 		goto abort;
4903 	}
4904 	disk->major = MAJOR(mddev->unit);
4905 	disk->first_minor = unit << shift;
4906 	if (name)
4907 		strcpy(disk->disk_name, name);
4908 	else if (partitioned)
4909 		sprintf(disk->disk_name, "md_d%d", unit);
4910 	else
4911 		sprintf(disk->disk_name, "md%d", unit);
4912 	disk->fops = &md_fops;
4913 	disk->private_data = mddev;
4914 	disk->queue = mddev->queue;
4915 	blk_queue_flush(mddev->queue, REQ_FLUSH | REQ_FUA);
4916 	/* Allow extended partitions.  This makes the
4917 	 * 'mdp' device redundant, but we can't really
4918 	 * remove it now.
4919 	 */
4920 	disk->flags |= GENHD_FL_EXT_DEVT;
4921 	mddev->gendisk = disk;
4922 	/* As soon as we call add_disk(), another thread could get
4923 	 * through to md_open, so make sure it doesn't get too far
4924 	 */
4925 	mutex_lock(&mddev->open_mutex);
4926 	add_disk(disk);
4927 
4928 	error = kobject_init_and_add(&mddev->kobj, &md_ktype,
4929 				     &disk_to_dev(disk)->kobj, "%s", "md");
4930 	if (error) {
4931 		/* This isn't possible, but as kobject_init_and_add is marked
4932 		 * __must_check, we must do something with the result
4933 		 */
4934 		printk(KERN_WARNING "md: cannot register %s/md - name in use\n",
4935 		       disk->disk_name);
4936 		error = 0;
4937 	}
4938 	if (mddev->kobj.sd &&
4939 	    sysfs_create_group(&mddev->kobj, &md_bitmap_group))
4940 		printk(KERN_DEBUG "pointless warning\n");
4941 	mutex_unlock(&mddev->open_mutex);
4942  abort:
4943 	mutex_unlock(&disks_mutex);
4944 	if (!error && mddev->kobj.sd) {
4945 		kobject_uevent(&mddev->kobj, KOBJ_ADD);
4946 		mddev->sysfs_state = sysfs_get_dirent_safe(mddev->kobj.sd, "array_state");
4947 	}
4948 	mddev_put(mddev);
4949 	return error;
4950 }
4951 
4952 static struct kobject *md_probe(dev_t dev, int *part, void *data)
4953 {
4954 	md_alloc(dev, NULL);
4955 	return NULL;
4956 }
4957 
4958 static int add_named_array(const char *val, struct kernel_param *kp)
4959 {
4960 	/* val must be "md_*" where * is not all digits.
4961 	 * We allocate an array with a large free minor number, and
4962 	 * set the name to val.  val must not already be an active name.
4963 	 */
4964 	int len = strlen(val);
4965 	char buf[DISK_NAME_LEN];
4966 
4967 	while (len && val[len-1] == '\n')
4968 		len--;
4969 	if (len >= DISK_NAME_LEN)
4970 		return -E2BIG;
4971 	strlcpy(buf, val, len+1);
4972 	if (strncmp(buf, "md_", 3) != 0)
4973 		return -EINVAL;
4974 	return md_alloc(0, buf);
4975 }
4976 
4977 static void md_safemode_timeout(unsigned long data)
4978 {
4979 	struct mddev *mddev = (struct mddev *) data;
4980 
4981 	if (!atomic_read(&mddev->writes_pending)) {
4982 		mddev->safemode = 1;
4983 		if (mddev->external)
4984 			sysfs_notify_dirent_safe(mddev->sysfs_state);
4985 	}
4986 	md_wakeup_thread(mddev->thread);
4987 }
4988 
4989 static int start_dirty_degraded;
4990 
4991 int md_run(struct mddev *mddev)
4992 {
4993 	int err;
4994 	struct md_rdev *rdev;
4995 	struct md_personality *pers;
4996 
4997 	if (list_empty(&mddev->disks))
4998 		/* cannot run an array with no devices.. */
4999 		return -EINVAL;
5000 
5001 	if (mddev->pers)
5002 		return -EBUSY;
5003 	/* Cannot run until previous stop completes properly */
5004 	if (mddev->sysfs_active)
5005 		return -EBUSY;
5006 
5007 	/*
5008 	 * Analyze all RAID superblock(s)
5009 	 */
5010 	if (!mddev->raid_disks) {
5011 		if (!mddev->persistent)
5012 			return -EINVAL;
5013 		analyze_sbs(mddev);
5014 	}
5015 
5016 	if (mddev->level != LEVEL_NONE)
5017 		request_module("md-level-%d", mddev->level);
5018 	else if (mddev->clevel[0])
5019 		request_module("md-%s", mddev->clevel);
5020 
5021 	/*
5022 	 * Drop all container device buffers, from now on
5023 	 * the only valid external interface is through the md
5024 	 * device.
5025 	 */
5026 	rdev_for_each(rdev, mddev) {
5027 		if (test_bit(Faulty, &rdev->flags))
5028 			continue;
5029 		sync_blockdev(rdev->bdev);
5030 		invalidate_bdev(rdev->bdev);
5031 
5032 		/* perform some consistency tests on the device.
5033 		 * We don't want the data to overlap the metadata,
5034 		 * Internal Bitmap issues have been handled elsewhere.
5035 		 */
5036 		if (rdev->meta_bdev) {
5037 			/* Nothing to check */;
5038 		} else if (rdev->data_offset < rdev->sb_start) {
5039 			if (mddev->dev_sectors &&
5040 			    rdev->data_offset + mddev->dev_sectors
5041 			    > rdev->sb_start) {
5042 				printk("md: %s: data overlaps metadata\n",
5043 				       mdname(mddev));
5044 				return -EINVAL;
5045 			}
5046 		} else {
5047 			if (rdev->sb_start + rdev->sb_size/512
5048 			    > rdev->data_offset) {
5049 				printk("md: %s: metadata overlaps data\n",
5050 				       mdname(mddev));
5051 				return -EINVAL;
5052 			}
5053 		}
5054 		sysfs_notify_dirent_safe(rdev->sysfs_state);
5055 	}
5056 
5057 	if (mddev->bio_set == NULL)
5058 		mddev->bio_set = bioset_create(BIO_POOL_SIZE,
5059 					       sizeof(struct mddev *));
5060 
5061 	spin_lock(&pers_lock);
5062 	pers = find_pers(mddev->level, mddev->clevel);
5063 	if (!pers || !try_module_get(pers->owner)) {
5064 		spin_unlock(&pers_lock);
5065 		if (mddev->level != LEVEL_NONE)
5066 			printk(KERN_WARNING "md: personality for level %d is not loaded!\n",
5067 			       mddev->level);
5068 		else
5069 			printk(KERN_WARNING "md: personality for level %s is not loaded!\n",
5070 			       mddev->clevel);
5071 		return -EINVAL;
5072 	}
5073 	mddev->pers = pers;
5074 	spin_unlock(&pers_lock);
5075 	if (mddev->level != pers->level) {
5076 		mddev->level = pers->level;
5077 		mddev->new_level = pers->level;
5078 	}
5079 	strlcpy(mddev->clevel, pers->name, sizeof(mddev->clevel));
5080 
5081 	if (mddev->reshape_position != MaxSector &&
5082 	    pers->start_reshape == NULL) {
5083 		/* This personality cannot handle reshaping... */
5084 		mddev->pers = NULL;
5085 		module_put(pers->owner);
5086 		return -EINVAL;
5087 	}
5088 
5089 	if (pers->sync_request) {
5090 		/* Warn if this is a potentially silly
5091 		 * configuration.
5092 		 */
5093 		char b[BDEVNAME_SIZE], b2[BDEVNAME_SIZE];
5094 		struct md_rdev *rdev2;
5095 		int warned = 0;
5096 
5097 		rdev_for_each(rdev, mddev)
5098 			rdev_for_each(rdev2, mddev) {
5099 				if (rdev < rdev2 &&
5100 				    rdev->bdev->bd_contains ==
5101 				    rdev2->bdev->bd_contains) {
5102 					printk(KERN_WARNING
5103 					       "%s: WARNING: %s appears to be"
5104 					       " on the same physical disk as"
5105 					       " %s.\n",
5106 					       mdname(mddev),
5107 					       bdevname(rdev->bdev,b),
5108 					       bdevname(rdev2->bdev,b2));
5109 					warned = 1;
5110 				}
5111 			}
5112 
5113 		if (warned)
5114 			printk(KERN_WARNING
5115 			       "True protection against single-disk"
5116 			       " failure might be compromised.\n");
5117 	}
5118 
5119 	mddev->recovery = 0;
5120 	/* may be over-ridden by personality */
5121 	mddev->resync_max_sectors = mddev->dev_sectors;
5122 
5123 	mddev->ok_start_degraded = start_dirty_degraded;
5124 
5125 	if (start_readonly && mddev->ro == 0)
5126 		mddev->ro = 2; /* read-only, but switch on first write */
5127 
5128 	err = mddev->pers->run(mddev);
5129 	if (err)
5130 		printk(KERN_ERR "md: pers->run() failed ...\n");
5131 	else if (mddev->pers->size(mddev, 0, 0) < mddev->array_sectors) {
5132 		WARN_ONCE(!mddev->external_size, "%s: default size too small,"
5133 			  " but 'external_size' not in effect?\n", __func__);
5134 		printk(KERN_ERR
5135 		       "md: invalid array_size %llu > default size %llu\n",
5136 		       (unsigned long long)mddev->array_sectors / 2,
5137 		       (unsigned long long)mddev->pers->size(mddev, 0, 0) / 2);
5138 		err = -EINVAL;
5139 		mddev->pers->stop(mddev);
5140 	}
5141 	if (err == 0 && mddev->pers->sync_request &&
5142 	    (mddev->bitmap_info.file || mddev->bitmap_info.offset)) {
5143 		err = bitmap_create(mddev);
5144 		if (err) {
5145 			printk(KERN_ERR "%s: failed to create bitmap (%d)\n",
5146 			       mdname(mddev), err);
5147 			mddev->pers->stop(mddev);
5148 		}
5149 	}
5150 	if (err) {
5151 		module_put(mddev->pers->owner);
5152 		mddev->pers = NULL;
5153 		bitmap_destroy(mddev);
5154 		return err;
5155 	}
5156 	if (mddev->pers->sync_request) {
5157 		if (mddev->kobj.sd &&
5158 		    sysfs_create_group(&mddev->kobj, &md_redundancy_group))
5159 			printk(KERN_WARNING
5160 			       "md: cannot register extra attributes for %s\n",
5161 			       mdname(mddev));
5162 		mddev->sysfs_action = sysfs_get_dirent_safe(mddev->kobj.sd, "sync_action");
5163 	} else if (mddev->ro == 2) /* auto-readonly not meaningful */
5164 		mddev->ro = 0;
5165 
5166  	atomic_set(&mddev->writes_pending,0);
5167 	atomic_set(&mddev->max_corr_read_errors,
5168 		   MD_DEFAULT_MAX_CORRECTED_READ_ERRORS);
5169 	mddev->safemode = 0;
5170 	mddev->safemode_timer.function = md_safemode_timeout;
5171 	mddev->safemode_timer.data = (unsigned long) mddev;
5172 	mddev->safemode_delay = (200 * HZ)/1000 +1; /* 200 msec delay */
5173 	mddev->in_sync = 1;
5174 	smp_wmb();
5175 	mddev->ready = 1;
5176 	rdev_for_each(rdev, mddev)
5177 		if (rdev->raid_disk >= 0)
5178 			if (sysfs_link_rdev(mddev, rdev))
5179 				/* failure here is OK */;
5180 
5181 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
5182 
5183 	if (mddev->flags)
5184 		md_update_sb(mddev, 0);
5185 
5186 	md_new_event(mddev);
5187 	sysfs_notify_dirent_safe(mddev->sysfs_state);
5188 	sysfs_notify_dirent_safe(mddev->sysfs_action);
5189 	sysfs_notify(&mddev->kobj, NULL, "degraded");
5190 	return 0;
5191 }
5192 EXPORT_SYMBOL_GPL(md_run);
5193 
5194 static int do_md_run(struct mddev *mddev)
5195 {
5196 	int err;
5197 
5198 	err = md_run(mddev);
5199 	if (err)
5200 		goto out;
5201 	err = bitmap_load(mddev);
5202 	if (err) {
5203 		bitmap_destroy(mddev);
5204 		goto out;
5205 	}
5206 
5207 	md_wakeup_thread(mddev->thread);
5208 	md_wakeup_thread(mddev->sync_thread); /* possibly kick off a reshape */
5209 
5210 	set_capacity(mddev->gendisk, mddev->array_sectors);
5211 	revalidate_disk(mddev->gendisk);
5212 	mddev->changed = 1;
5213 	kobject_uevent(&disk_to_dev(mddev->gendisk)->kobj, KOBJ_CHANGE);
5214 out:
5215 	return err;
5216 }
5217 
5218 static int restart_array(struct mddev *mddev)
5219 {
5220 	struct gendisk *disk = mddev->gendisk;
5221 
5222 	/* Complain if it has no devices */
5223 	if (list_empty(&mddev->disks))
5224 		return -ENXIO;
5225 	if (!mddev->pers)
5226 		return -EINVAL;
5227 	if (!mddev->ro)
5228 		return -EBUSY;
5229 	mddev->safemode = 0;
5230 	mddev->ro = 0;
5231 	set_disk_ro(disk, 0);
5232 	printk(KERN_INFO "md: %s switched to read-write mode.\n",
5233 		mdname(mddev));
5234 	/* Kick recovery or resync if necessary */
5235 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
5236 	md_wakeup_thread(mddev->thread);
5237 	md_wakeup_thread(mddev->sync_thread);
5238 	sysfs_notify_dirent_safe(mddev->sysfs_state);
5239 	return 0;
5240 }
5241 
5242 /* similar to deny_write_access, but accounts for our holding a reference
5243  * to the file ourselves */
5244 static int deny_bitmap_write_access(struct file * file)
5245 {
5246 	struct inode *inode = file->f_mapping->host;
5247 
5248 	spin_lock(&inode->i_lock);
5249 	if (atomic_read(&inode->i_writecount) > 1) {
5250 		spin_unlock(&inode->i_lock);
5251 		return -ETXTBSY;
5252 	}
5253 	atomic_set(&inode->i_writecount, -1);
5254 	spin_unlock(&inode->i_lock);
5255 
5256 	return 0;
5257 }
5258 
5259 void restore_bitmap_write_access(struct file *file)
5260 {
5261 	struct inode *inode = file->f_mapping->host;
5262 
5263 	spin_lock(&inode->i_lock);
5264 	atomic_set(&inode->i_writecount, 1);
5265 	spin_unlock(&inode->i_lock);
5266 }
5267 
5268 static void md_clean(struct mddev *mddev)
5269 {
5270 	mddev->array_sectors = 0;
5271 	mddev->external_size = 0;
5272 	mddev->dev_sectors = 0;
5273 	mddev->raid_disks = 0;
5274 	mddev->recovery_cp = 0;
5275 	mddev->resync_min = 0;
5276 	mddev->resync_max = MaxSector;
5277 	mddev->reshape_position = MaxSector;
5278 	mddev->external = 0;
5279 	mddev->persistent = 0;
5280 	mddev->level = LEVEL_NONE;
5281 	mddev->clevel[0] = 0;
5282 	mddev->flags = 0;
5283 	mddev->ro = 0;
5284 	mddev->metadata_type[0] = 0;
5285 	mddev->chunk_sectors = 0;
5286 	mddev->ctime = mddev->utime = 0;
5287 	mddev->layout = 0;
5288 	mddev->max_disks = 0;
5289 	mddev->events = 0;
5290 	mddev->can_decrease_events = 0;
5291 	mddev->delta_disks = 0;
5292 	mddev->reshape_backwards = 0;
5293 	mddev->new_level = LEVEL_NONE;
5294 	mddev->new_layout = 0;
5295 	mddev->new_chunk_sectors = 0;
5296 	mddev->curr_resync = 0;
5297 	mddev->resync_mismatches = 0;
5298 	mddev->suspend_lo = mddev->suspend_hi = 0;
5299 	mddev->sync_speed_min = mddev->sync_speed_max = 0;
5300 	mddev->recovery = 0;
5301 	mddev->in_sync = 0;
5302 	mddev->changed = 0;
5303 	mddev->degraded = 0;
5304 	mddev->safemode = 0;
5305 	mddev->merge_check_needed = 0;
5306 	mddev->bitmap_info.offset = 0;
5307 	mddev->bitmap_info.default_offset = 0;
5308 	mddev->bitmap_info.default_space = 0;
5309 	mddev->bitmap_info.chunksize = 0;
5310 	mddev->bitmap_info.daemon_sleep = 0;
5311 	mddev->bitmap_info.max_write_behind = 0;
5312 }
5313 
5314 static void __md_stop_writes(struct mddev *mddev)
5315 {
5316 	if (mddev->sync_thread) {
5317 		set_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
5318 		set_bit(MD_RECOVERY_INTR, &mddev->recovery);
5319 		reap_sync_thread(mddev);
5320 	}
5321 
5322 	del_timer_sync(&mddev->safemode_timer);
5323 
5324 	bitmap_flush(mddev);
5325 	md_super_wait(mddev);
5326 
5327 	if (!mddev->in_sync || mddev->flags) {
5328 		/* mark array as shutdown cleanly */
5329 		mddev->in_sync = 1;
5330 		md_update_sb(mddev, 1);
5331 	}
5332 }
5333 
5334 void md_stop_writes(struct mddev *mddev)
5335 {
5336 	mddev_lock(mddev);
5337 	__md_stop_writes(mddev);
5338 	mddev_unlock(mddev);
5339 }
5340 EXPORT_SYMBOL_GPL(md_stop_writes);
5341 
5342 void md_stop(struct mddev *mddev)
5343 {
5344 	mddev->ready = 0;
5345 	mddev->pers->stop(mddev);
5346 	if (mddev->pers->sync_request && mddev->to_remove == NULL)
5347 		mddev->to_remove = &md_redundancy_group;
5348 	module_put(mddev->pers->owner);
5349 	mddev->pers = NULL;
5350 	clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
5351 }
5352 EXPORT_SYMBOL_GPL(md_stop);
5353 
5354 static int md_set_readonly(struct mddev *mddev, int is_open)
5355 {
5356 	int err = 0;
5357 	mutex_lock(&mddev->open_mutex);
5358 	if (atomic_read(&mddev->openers) > is_open) {
5359 		printk("md: %s still in use.\n",mdname(mddev));
5360 		err = -EBUSY;
5361 		goto out;
5362 	}
5363 	if (mddev->pers) {
5364 		__md_stop_writes(mddev);
5365 
5366 		err  = -ENXIO;
5367 		if (mddev->ro==1)
5368 			goto out;
5369 		mddev->ro = 1;
5370 		set_disk_ro(mddev->gendisk, 1);
5371 		clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
5372 		sysfs_notify_dirent_safe(mddev->sysfs_state);
5373 		err = 0;
5374 	}
5375 out:
5376 	mutex_unlock(&mddev->open_mutex);
5377 	return err;
5378 }
5379 
5380 /* mode:
5381  *   0 - completely stop and dis-assemble array
5382  *   2 - stop but do not disassemble array
5383  */
5384 static int do_md_stop(struct mddev * mddev, int mode, int is_open)
5385 {
5386 	struct gendisk *disk = mddev->gendisk;
5387 	struct md_rdev *rdev;
5388 
5389 	mutex_lock(&mddev->open_mutex);
5390 	if (atomic_read(&mddev->openers) > is_open ||
5391 	    mddev->sysfs_active) {
5392 		printk("md: %s still in use.\n",mdname(mddev));
5393 		mutex_unlock(&mddev->open_mutex);
5394 		return -EBUSY;
5395 	}
5396 
5397 	if (mddev->pers) {
5398 		if (mddev->ro)
5399 			set_disk_ro(disk, 0);
5400 
5401 		__md_stop_writes(mddev);
5402 		md_stop(mddev);
5403 		mddev->queue->merge_bvec_fn = NULL;
5404 		mddev->queue->backing_dev_info.congested_fn = NULL;
5405 
5406 		/* tell userspace to handle 'inactive' */
5407 		sysfs_notify_dirent_safe(mddev->sysfs_state);
5408 
5409 		rdev_for_each(rdev, mddev)
5410 			if (rdev->raid_disk >= 0)
5411 				sysfs_unlink_rdev(mddev, rdev);
5412 
5413 		set_capacity(disk, 0);
5414 		mutex_unlock(&mddev->open_mutex);
5415 		mddev->changed = 1;
5416 		revalidate_disk(disk);
5417 
5418 		if (mddev->ro)
5419 			mddev->ro = 0;
5420 	} else
5421 		mutex_unlock(&mddev->open_mutex);
5422 	/*
5423 	 * Free resources if final stop
5424 	 */
5425 	if (mode == 0) {
5426 		printk(KERN_INFO "md: %s stopped.\n", mdname(mddev));
5427 
5428 		bitmap_destroy(mddev);
5429 		if (mddev->bitmap_info.file) {
5430 			restore_bitmap_write_access(mddev->bitmap_info.file);
5431 			fput(mddev->bitmap_info.file);
5432 			mddev->bitmap_info.file = NULL;
5433 		}
5434 		mddev->bitmap_info.offset = 0;
5435 
5436 		export_array(mddev);
5437 
5438 		md_clean(mddev);
5439 		kobject_uevent(&disk_to_dev(mddev->gendisk)->kobj, KOBJ_CHANGE);
5440 		if (mddev->hold_active == UNTIL_STOP)
5441 			mddev->hold_active = 0;
5442 	}
5443 	blk_integrity_unregister(disk);
5444 	md_new_event(mddev);
5445 	sysfs_notify_dirent_safe(mddev->sysfs_state);
5446 	return 0;
5447 }
5448 
5449 #ifndef MODULE
5450 static void autorun_array(struct mddev *mddev)
5451 {
5452 	struct md_rdev *rdev;
5453 	int err;
5454 
5455 	if (list_empty(&mddev->disks))
5456 		return;
5457 
5458 	printk(KERN_INFO "md: running: ");
5459 
5460 	rdev_for_each(rdev, mddev) {
5461 		char b[BDEVNAME_SIZE];
5462 		printk("<%s>", bdevname(rdev->bdev,b));
5463 	}
5464 	printk("\n");
5465 
5466 	err = do_md_run(mddev);
5467 	if (err) {
5468 		printk(KERN_WARNING "md: do_md_run() returned %d\n", err);
5469 		do_md_stop(mddev, 0, 0);
5470 	}
5471 }
5472 
5473 /*
5474  * lets try to run arrays based on all disks that have arrived
5475  * until now. (those are in pending_raid_disks)
5476  *
5477  * the method: pick the first pending disk, collect all disks with
5478  * the same UUID, remove all from the pending list and put them into
5479  * the 'same_array' list. Then order this list based on superblock
5480  * update time (freshest comes first), kick out 'old' disks and
5481  * compare superblocks. If everything's fine then run it.
5482  *
5483  * If "unit" is allocated, then bump its reference count
5484  */
5485 static void autorun_devices(int part)
5486 {
5487 	struct md_rdev *rdev0, *rdev, *tmp;
5488 	struct mddev *mddev;
5489 	char b[BDEVNAME_SIZE];
5490 
5491 	printk(KERN_INFO "md: autorun ...\n");
5492 	while (!list_empty(&pending_raid_disks)) {
5493 		int unit;
5494 		dev_t dev;
5495 		LIST_HEAD(candidates);
5496 		rdev0 = list_entry(pending_raid_disks.next,
5497 					 struct md_rdev, same_set);
5498 
5499 		printk(KERN_INFO "md: considering %s ...\n",
5500 			bdevname(rdev0->bdev,b));
5501 		INIT_LIST_HEAD(&candidates);
5502 		rdev_for_each_list(rdev, tmp, &pending_raid_disks)
5503 			if (super_90_load(rdev, rdev0, 0) >= 0) {
5504 				printk(KERN_INFO "md:  adding %s ...\n",
5505 					bdevname(rdev->bdev,b));
5506 				list_move(&rdev->same_set, &candidates);
5507 			}
5508 		/*
5509 		 * now we have a set of devices, with all of them having
5510 		 * mostly sane superblocks. It's time to allocate the
5511 		 * mddev.
5512 		 */
5513 		if (part) {
5514 			dev = MKDEV(mdp_major,
5515 				    rdev0->preferred_minor << MdpMinorShift);
5516 			unit = MINOR(dev) >> MdpMinorShift;
5517 		} else {
5518 			dev = MKDEV(MD_MAJOR, rdev0->preferred_minor);
5519 			unit = MINOR(dev);
5520 		}
5521 		if (rdev0->preferred_minor != unit) {
5522 			printk(KERN_INFO "md: unit number in %s is bad: %d\n",
5523 			       bdevname(rdev0->bdev, b), rdev0->preferred_minor);
5524 			break;
5525 		}
5526 
5527 		md_probe(dev, NULL, NULL);
5528 		mddev = mddev_find(dev);
5529 		if (!mddev || !mddev->gendisk) {
5530 			if (mddev)
5531 				mddev_put(mddev);
5532 			printk(KERN_ERR
5533 				"md: cannot allocate memory for md drive.\n");
5534 			break;
5535 		}
5536 		if (mddev_lock(mddev))
5537 			printk(KERN_WARNING "md: %s locked, cannot run\n",
5538 			       mdname(mddev));
5539 		else if (mddev->raid_disks || mddev->major_version
5540 			 || !list_empty(&mddev->disks)) {
5541 			printk(KERN_WARNING
5542 				"md: %s already running, cannot run %s\n",
5543 				mdname(mddev), bdevname(rdev0->bdev,b));
5544 			mddev_unlock(mddev);
5545 		} else {
5546 			printk(KERN_INFO "md: created %s\n", mdname(mddev));
5547 			mddev->persistent = 1;
5548 			rdev_for_each_list(rdev, tmp, &candidates) {
5549 				list_del_init(&rdev->same_set);
5550 				if (bind_rdev_to_array(rdev, mddev))
5551 					export_rdev(rdev);
5552 			}
5553 			autorun_array(mddev);
5554 			mddev_unlock(mddev);
5555 		}
5556 		/* on success, candidates will be empty, on error
5557 		 * it won't...
5558 		 */
5559 		rdev_for_each_list(rdev, tmp, &candidates) {
5560 			list_del_init(&rdev->same_set);
5561 			export_rdev(rdev);
5562 		}
5563 		mddev_put(mddev);
5564 	}
5565 	printk(KERN_INFO "md: ... autorun DONE.\n");
5566 }
5567 #endif /* !MODULE */
5568 
5569 static int get_version(void __user * arg)
5570 {
5571 	mdu_version_t ver;
5572 
5573 	ver.major = MD_MAJOR_VERSION;
5574 	ver.minor = MD_MINOR_VERSION;
5575 	ver.patchlevel = MD_PATCHLEVEL_VERSION;
5576 
5577 	if (copy_to_user(arg, &ver, sizeof(ver)))
5578 		return -EFAULT;
5579 
5580 	return 0;
5581 }
5582 
5583 static int get_array_info(struct mddev * mddev, void __user * arg)
5584 {
5585 	mdu_array_info_t info;
5586 	int nr,working,insync,failed,spare;
5587 	struct md_rdev *rdev;
5588 
5589 	nr=working=insync=failed=spare=0;
5590 	rdev_for_each(rdev, mddev) {
5591 		nr++;
5592 		if (test_bit(Faulty, &rdev->flags))
5593 			failed++;
5594 		else {
5595 			working++;
5596 			if (test_bit(In_sync, &rdev->flags))
5597 				insync++;
5598 			else
5599 				spare++;
5600 		}
5601 	}
5602 
5603 	info.major_version = mddev->major_version;
5604 	info.minor_version = mddev->minor_version;
5605 	info.patch_version = MD_PATCHLEVEL_VERSION;
5606 	info.ctime         = mddev->ctime;
5607 	info.level         = mddev->level;
5608 	info.size          = mddev->dev_sectors / 2;
5609 	if (info.size != mddev->dev_sectors / 2) /* overflow */
5610 		info.size = -1;
5611 	info.nr_disks      = nr;
5612 	info.raid_disks    = mddev->raid_disks;
5613 	info.md_minor      = mddev->md_minor;
5614 	info.not_persistent= !mddev->persistent;
5615 
5616 	info.utime         = mddev->utime;
5617 	info.state         = 0;
5618 	if (mddev->in_sync)
5619 		info.state = (1<<MD_SB_CLEAN);
5620 	if (mddev->bitmap && mddev->bitmap_info.offset)
5621 		info.state = (1<<MD_SB_BITMAP_PRESENT);
5622 	info.active_disks  = insync;
5623 	info.working_disks = working;
5624 	info.failed_disks  = failed;
5625 	info.spare_disks   = spare;
5626 
5627 	info.layout        = mddev->layout;
5628 	info.chunk_size    = mddev->chunk_sectors << 9;
5629 
5630 	if (copy_to_user(arg, &info, sizeof(info)))
5631 		return -EFAULT;
5632 
5633 	return 0;
5634 }
5635 
5636 static int get_bitmap_file(struct mddev * mddev, void __user * arg)
5637 {
5638 	mdu_bitmap_file_t *file = NULL; /* too big for stack allocation */
5639 	char *ptr, *buf = NULL;
5640 	int err = -ENOMEM;
5641 
5642 	if (md_allow_write(mddev))
5643 		file = kmalloc(sizeof(*file), GFP_NOIO);
5644 	else
5645 		file = kmalloc(sizeof(*file), GFP_KERNEL);
5646 
5647 	if (!file)
5648 		goto out;
5649 
5650 	/* bitmap disabled, zero the first byte and copy out */
5651 	if (!mddev->bitmap || !mddev->bitmap->storage.file) {
5652 		file->pathname[0] = '\0';
5653 		goto copy_out;
5654 	}
5655 
5656 	buf = kmalloc(sizeof(file->pathname), GFP_KERNEL);
5657 	if (!buf)
5658 		goto out;
5659 
5660 	ptr = d_path(&mddev->bitmap->storage.file->f_path,
5661 		     buf, sizeof(file->pathname));
5662 	if (IS_ERR(ptr))
5663 		goto out;
5664 
5665 	strcpy(file->pathname, ptr);
5666 
5667 copy_out:
5668 	err = 0;
5669 	if (copy_to_user(arg, file, sizeof(*file)))
5670 		err = -EFAULT;
5671 out:
5672 	kfree(buf);
5673 	kfree(file);
5674 	return err;
5675 }
5676 
5677 static int get_disk_info(struct mddev * mddev, void __user * arg)
5678 {
5679 	mdu_disk_info_t info;
5680 	struct md_rdev *rdev;
5681 
5682 	if (copy_from_user(&info, arg, sizeof(info)))
5683 		return -EFAULT;
5684 
5685 	rdev = find_rdev_nr(mddev, info.number);
5686 	if (rdev) {
5687 		info.major = MAJOR(rdev->bdev->bd_dev);
5688 		info.minor = MINOR(rdev->bdev->bd_dev);
5689 		info.raid_disk = rdev->raid_disk;
5690 		info.state = 0;
5691 		if (test_bit(Faulty, &rdev->flags))
5692 			info.state |= (1<<MD_DISK_FAULTY);
5693 		else if (test_bit(In_sync, &rdev->flags)) {
5694 			info.state |= (1<<MD_DISK_ACTIVE);
5695 			info.state |= (1<<MD_DISK_SYNC);
5696 		}
5697 		if (test_bit(WriteMostly, &rdev->flags))
5698 			info.state |= (1<<MD_DISK_WRITEMOSTLY);
5699 	} else {
5700 		info.major = info.minor = 0;
5701 		info.raid_disk = -1;
5702 		info.state = (1<<MD_DISK_REMOVED);
5703 	}
5704 
5705 	if (copy_to_user(arg, &info, sizeof(info)))
5706 		return -EFAULT;
5707 
5708 	return 0;
5709 }
5710 
5711 static int add_new_disk(struct mddev * mddev, mdu_disk_info_t *info)
5712 {
5713 	char b[BDEVNAME_SIZE], b2[BDEVNAME_SIZE];
5714 	struct md_rdev *rdev;
5715 	dev_t dev = MKDEV(info->major,info->minor);
5716 
5717 	if (info->major != MAJOR(dev) || info->minor != MINOR(dev))
5718 		return -EOVERFLOW;
5719 
5720 	if (!mddev->raid_disks) {
5721 		int err;
5722 		/* expecting a device which has a superblock */
5723 		rdev = md_import_device(dev, mddev->major_version, mddev->minor_version);
5724 		if (IS_ERR(rdev)) {
5725 			printk(KERN_WARNING
5726 				"md: md_import_device returned %ld\n",
5727 				PTR_ERR(rdev));
5728 			return PTR_ERR(rdev);
5729 		}
5730 		if (!list_empty(&mddev->disks)) {
5731 			struct md_rdev *rdev0
5732 				= list_entry(mddev->disks.next,
5733 					     struct md_rdev, same_set);
5734 			err = super_types[mddev->major_version]
5735 				.load_super(rdev, rdev0, mddev->minor_version);
5736 			if (err < 0) {
5737 				printk(KERN_WARNING
5738 					"md: %s has different UUID to %s\n",
5739 					bdevname(rdev->bdev,b),
5740 					bdevname(rdev0->bdev,b2));
5741 				export_rdev(rdev);
5742 				return -EINVAL;
5743 			}
5744 		}
5745 		err = bind_rdev_to_array(rdev, mddev);
5746 		if (err)
5747 			export_rdev(rdev);
5748 		return err;
5749 	}
5750 
5751 	/*
5752 	 * add_new_disk can be used once the array is assembled
5753 	 * to add "hot spares".  They must already have a superblock
5754 	 * written
5755 	 */
5756 	if (mddev->pers) {
5757 		int err;
5758 		if (!mddev->pers->hot_add_disk) {
5759 			printk(KERN_WARNING
5760 				"%s: personality does not support diskops!\n",
5761 			       mdname(mddev));
5762 			return -EINVAL;
5763 		}
5764 		if (mddev->persistent)
5765 			rdev = md_import_device(dev, mddev->major_version,
5766 						mddev->minor_version);
5767 		else
5768 			rdev = md_import_device(dev, -1, -1);
5769 		if (IS_ERR(rdev)) {
5770 			printk(KERN_WARNING
5771 				"md: md_import_device returned %ld\n",
5772 				PTR_ERR(rdev));
5773 			return PTR_ERR(rdev);
5774 		}
5775 		/* set saved_raid_disk if appropriate */
5776 		if (!mddev->persistent) {
5777 			if (info->state & (1<<MD_DISK_SYNC)  &&
5778 			    info->raid_disk < mddev->raid_disks) {
5779 				rdev->raid_disk = info->raid_disk;
5780 				set_bit(In_sync, &rdev->flags);
5781 			} else
5782 				rdev->raid_disk = -1;
5783 		} else
5784 			super_types[mddev->major_version].
5785 				validate_super(mddev, rdev);
5786 		if ((info->state & (1<<MD_DISK_SYNC)) &&
5787 		     rdev->raid_disk != info->raid_disk) {
5788 			/* This was a hot-add request, but events doesn't
5789 			 * match, so reject it.
5790 			 */
5791 			export_rdev(rdev);
5792 			return -EINVAL;
5793 		}
5794 
5795 		if (test_bit(In_sync, &rdev->flags))
5796 			rdev->saved_raid_disk = rdev->raid_disk;
5797 		else
5798 			rdev->saved_raid_disk = -1;
5799 
5800 		clear_bit(In_sync, &rdev->flags); /* just to be sure */
5801 		if (info->state & (1<<MD_DISK_WRITEMOSTLY))
5802 			set_bit(WriteMostly, &rdev->flags);
5803 		else
5804 			clear_bit(WriteMostly, &rdev->flags);
5805 
5806 		rdev->raid_disk = -1;
5807 		err = bind_rdev_to_array(rdev, mddev);
5808 		if (!err && !mddev->pers->hot_remove_disk) {
5809 			/* If there is hot_add_disk but no hot_remove_disk
5810 			 * then added disks for geometry changes,
5811 			 * and should be added immediately.
5812 			 */
5813 			super_types[mddev->major_version].
5814 				validate_super(mddev, rdev);
5815 			err = mddev->pers->hot_add_disk(mddev, rdev);
5816 			if (err)
5817 				unbind_rdev_from_array(rdev);
5818 		}
5819 		if (err)
5820 			export_rdev(rdev);
5821 		else
5822 			sysfs_notify_dirent_safe(rdev->sysfs_state);
5823 
5824 		md_update_sb(mddev, 1);
5825 		if (mddev->degraded)
5826 			set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
5827 		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
5828 		if (!err)
5829 			md_new_event(mddev);
5830 		md_wakeup_thread(mddev->thread);
5831 		return err;
5832 	}
5833 
5834 	/* otherwise, add_new_disk is only allowed
5835 	 * for major_version==0 superblocks
5836 	 */
5837 	if (mddev->major_version != 0) {
5838 		printk(KERN_WARNING "%s: ADD_NEW_DISK not supported\n",
5839 		       mdname(mddev));
5840 		return -EINVAL;
5841 	}
5842 
5843 	if (!(info->state & (1<<MD_DISK_FAULTY))) {
5844 		int err;
5845 		rdev = md_import_device(dev, -1, 0);
5846 		if (IS_ERR(rdev)) {
5847 			printk(KERN_WARNING
5848 				"md: error, md_import_device() returned %ld\n",
5849 				PTR_ERR(rdev));
5850 			return PTR_ERR(rdev);
5851 		}
5852 		rdev->desc_nr = info->number;
5853 		if (info->raid_disk < mddev->raid_disks)
5854 			rdev->raid_disk = info->raid_disk;
5855 		else
5856 			rdev->raid_disk = -1;
5857 
5858 		if (rdev->raid_disk < mddev->raid_disks)
5859 			if (info->state & (1<<MD_DISK_SYNC))
5860 				set_bit(In_sync, &rdev->flags);
5861 
5862 		if (info->state & (1<<MD_DISK_WRITEMOSTLY))
5863 			set_bit(WriteMostly, &rdev->flags);
5864 
5865 		if (!mddev->persistent) {
5866 			printk(KERN_INFO "md: nonpersistent superblock ...\n");
5867 			rdev->sb_start = i_size_read(rdev->bdev->bd_inode) / 512;
5868 		} else
5869 			rdev->sb_start = calc_dev_sboffset(rdev);
5870 		rdev->sectors = rdev->sb_start;
5871 
5872 		err = bind_rdev_to_array(rdev, mddev);
5873 		if (err) {
5874 			export_rdev(rdev);
5875 			return err;
5876 		}
5877 	}
5878 
5879 	return 0;
5880 }
5881 
5882 static int hot_remove_disk(struct mddev * mddev, dev_t dev)
5883 {
5884 	char b[BDEVNAME_SIZE];
5885 	struct md_rdev *rdev;
5886 
5887 	rdev = find_rdev(mddev, dev);
5888 	if (!rdev)
5889 		return -ENXIO;
5890 
5891 	if (rdev->raid_disk >= 0)
5892 		goto busy;
5893 
5894 	kick_rdev_from_array(rdev);
5895 	md_update_sb(mddev, 1);
5896 	md_new_event(mddev);
5897 
5898 	return 0;
5899 busy:
5900 	printk(KERN_WARNING "md: cannot remove active disk %s from %s ...\n",
5901 		bdevname(rdev->bdev,b), mdname(mddev));
5902 	return -EBUSY;
5903 }
5904 
5905 static int hot_add_disk(struct mddev * mddev, dev_t dev)
5906 {
5907 	char b[BDEVNAME_SIZE];
5908 	int err;
5909 	struct md_rdev *rdev;
5910 
5911 	if (!mddev->pers)
5912 		return -ENODEV;
5913 
5914 	if (mddev->major_version != 0) {
5915 		printk(KERN_WARNING "%s: HOT_ADD may only be used with"
5916 			" version-0 superblocks.\n",
5917 			mdname(mddev));
5918 		return -EINVAL;
5919 	}
5920 	if (!mddev->pers->hot_add_disk) {
5921 		printk(KERN_WARNING
5922 			"%s: personality does not support diskops!\n",
5923 			mdname(mddev));
5924 		return -EINVAL;
5925 	}
5926 
5927 	rdev = md_import_device(dev, -1, 0);
5928 	if (IS_ERR(rdev)) {
5929 		printk(KERN_WARNING
5930 			"md: error, md_import_device() returned %ld\n",
5931 			PTR_ERR(rdev));
5932 		return -EINVAL;
5933 	}
5934 
5935 	if (mddev->persistent)
5936 		rdev->sb_start = calc_dev_sboffset(rdev);
5937 	else
5938 		rdev->sb_start = i_size_read(rdev->bdev->bd_inode) / 512;
5939 
5940 	rdev->sectors = rdev->sb_start;
5941 
5942 	if (test_bit(Faulty, &rdev->flags)) {
5943 		printk(KERN_WARNING
5944 			"md: can not hot-add faulty %s disk to %s!\n",
5945 			bdevname(rdev->bdev,b), mdname(mddev));
5946 		err = -EINVAL;
5947 		goto abort_export;
5948 	}
5949 	clear_bit(In_sync, &rdev->flags);
5950 	rdev->desc_nr = -1;
5951 	rdev->saved_raid_disk = -1;
5952 	err = bind_rdev_to_array(rdev, mddev);
5953 	if (err)
5954 		goto abort_export;
5955 
5956 	/*
5957 	 * The rest should better be atomic, we can have disk failures
5958 	 * noticed in interrupt contexts ...
5959 	 */
5960 
5961 	rdev->raid_disk = -1;
5962 
5963 	md_update_sb(mddev, 1);
5964 
5965 	/*
5966 	 * Kick recovery, maybe this spare has to be added to the
5967 	 * array immediately.
5968 	 */
5969 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
5970 	md_wakeup_thread(mddev->thread);
5971 	md_new_event(mddev);
5972 	return 0;
5973 
5974 abort_export:
5975 	export_rdev(rdev);
5976 	return err;
5977 }
5978 
5979 static int set_bitmap_file(struct mddev *mddev, int fd)
5980 {
5981 	int err;
5982 
5983 	if (mddev->pers) {
5984 		if (!mddev->pers->quiesce)
5985 			return -EBUSY;
5986 		if (mddev->recovery || mddev->sync_thread)
5987 			return -EBUSY;
5988 		/* we should be able to change the bitmap.. */
5989 	}
5990 
5991 
5992 	if (fd >= 0) {
5993 		if (mddev->bitmap)
5994 			return -EEXIST; /* cannot add when bitmap is present */
5995 		mddev->bitmap_info.file = fget(fd);
5996 
5997 		if (mddev->bitmap_info.file == NULL) {
5998 			printk(KERN_ERR "%s: error: failed to get bitmap file\n",
5999 			       mdname(mddev));
6000 			return -EBADF;
6001 		}
6002 
6003 		err = deny_bitmap_write_access(mddev->bitmap_info.file);
6004 		if (err) {
6005 			printk(KERN_ERR "%s: error: bitmap file is already in use\n",
6006 			       mdname(mddev));
6007 			fput(mddev->bitmap_info.file);
6008 			mddev->bitmap_info.file = NULL;
6009 			return err;
6010 		}
6011 		mddev->bitmap_info.offset = 0; /* file overrides offset */
6012 	} else if (mddev->bitmap == NULL)
6013 		return -ENOENT; /* cannot remove what isn't there */
6014 	err = 0;
6015 	if (mddev->pers) {
6016 		mddev->pers->quiesce(mddev, 1);
6017 		if (fd >= 0) {
6018 			err = bitmap_create(mddev);
6019 			if (!err)
6020 				err = bitmap_load(mddev);
6021 		}
6022 		if (fd < 0 || err) {
6023 			bitmap_destroy(mddev);
6024 			fd = -1; /* make sure to put the file */
6025 		}
6026 		mddev->pers->quiesce(mddev, 0);
6027 	}
6028 	if (fd < 0) {
6029 		if (mddev->bitmap_info.file) {
6030 			restore_bitmap_write_access(mddev->bitmap_info.file);
6031 			fput(mddev->bitmap_info.file);
6032 		}
6033 		mddev->bitmap_info.file = NULL;
6034 	}
6035 
6036 	return err;
6037 }
6038 
6039 /*
6040  * set_array_info is used two different ways
6041  * The original usage is when creating a new array.
6042  * In this usage, raid_disks is > 0 and it together with
6043  *  level, size, not_persistent,layout,chunksize determine the
6044  *  shape of the array.
6045  *  This will always create an array with a type-0.90.0 superblock.
6046  * The newer usage is when assembling an array.
6047  *  In this case raid_disks will be 0, and the major_version field is
6048  *  use to determine which style super-blocks are to be found on the devices.
6049  *  The minor and patch _version numbers are also kept incase the
6050  *  super_block handler wishes to interpret them.
6051  */
6052 static int set_array_info(struct mddev * mddev, mdu_array_info_t *info)
6053 {
6054 
6055 	if (info->raid_disks == 0) {
6056 		/* just setting version number for superblock loading */
6057 		if (info->major_version < 0 ||
6058 		    info->major_version >= ARRAY_SIZE(super_types) ||
6059 		    super_types[info->major_version].name == NULL) {
6060 			/* maybe try to auto-load a module? */
6061 			printk(KERN_INFO
6062 				"md: superblock version %d not known\n",
6063 				info->major_version);
6064 			return -EINVAL;
6065 		}
6066 		mddev->major_version = info->major_version;
6067 		mddev->minor_version = info->minor_version;
6068 		mddev->patch_version = info->patch_version;
6069 		mddev->persistent = !info->not_persistent;
6070 		/* ensure mddev_put doesn't delete this now that there
6071 		 * is some minimal configuration.
6072 		 */
6073 		mddev->ctime         = get_seconds();
6074 		return 0;
6075 	}
6076 	mddev->major_version = MD_MAJOR_VERSION;
6077 	mddev->minor_version = MD_MINOR_VERSION;
6078 	mddev->patch_version = MD_PATCHLEVEL_VERSION;
6079 	mddev->ctime         = get_seconds();
6080 
6081 	mddev->level         = info->level;
6082 	mddev->clevel[0]     = 0;
6083 	mddev->dev_sectors   = 2 * (sector_t)info->size;
6084 	mddev->raid_disks    = info->raid_disks;
6085 	/* don't set md_minor, it is determined by which /dev/md* was
6086 	 * openned
6087 	 */
6088 	if (info->state & (1<<MD_SB_CLEAN))
6089 		mddev->recovery_cp = MaxSector;
6090 	else
6091 		mddev->recovery_cp = 0;
6092 	mddev->persistent    = ! info->not_persistent;
6093 	mddev->external	     = 0;
6094 
6095 	mddev->layout        = info->layout;
6096 	mddev->chunk_sectors = info->chunk_size >> 9;
6097 
6098 	mddev->max_disks     = MD_SB_DISKS;
6099 
6100 	if (mddev->persistent)
6101 		mddev->flags         = 0;
6102 	set_bit(MD_CHANGE_DEVS, &mddev->flags);
6103 
6104 	mddev->bitmap_info.default_offset = MD_SB_BYTES >> 9;
6105 	mddev->bitmap_info.default_space = 64*2 - (MD_SB_BYTES >> 9);
6106 	mddev->bitmap_info.offset = 0;
6107 
6108 	mddev->reshape_position = MaxSector;
6109 
6110 	/*
6111 	 * Generate a 128 bit UUID
6112 	 */
6113 	get_random_bytes(mddev->uuid, 16);
6114 
6115 	mddev->new_level = mddev->level;
6116 	mddev->new_chunk_sectors = mddev->chunk_sectors;
6117 	mddev->new_layout = mddev->layout;
6118 	mddev->delta_disks = 0;
6119 	mddev->reshape_backwards = 0;
6120 
6121 	return 0;
6122 }
6123 
6124 void md_set_array_sectors(struct mddev *mddev, sector_t array_sectors)
6125 {
6126 	WARN(!mddev_is_locked(mddev), "%s: unlocked mddev!\n", __func__);
6127 
6128 	if (mddev->external_size)
6129 		return;
6130 
6131 	mddev->array_sectors = array_sectors;
6132 }
6133 EXPORT_SYMBOL(md_set_array_sectors);
6134 
6135 static int update_size(struct mddev *mddev, sector_t num_sectors)
6136 {
6137 	struct md_rdev *rdev;
6138 	int rv;
6139 	int fit = (num_sectors == 0);
6140 
6141 	if (mddev->pers->resize == NULL)
6142 		return -EINVAL;
6143 	/* The "num_sectors" is the number of sectors of each device that
6144 	 * is used.  This can only make sense for arrays with redundancy.
6145 	 * linear and raid0 always use whatever space is available. We can only
6146 	 * consider changing this number if no resync or reconstruction is
6147 	 * happening, and if the new size is acceptable. It must fit before the
6148 	 * sb_start or, if that is <data_offset, it must fit before the size
6149 	 * of each device.  If num_sectors is zero, we find the largest size
6150 	 * that fits.
6151 	 */
6152 	if (mddev->sync_thread)
6153 		return -EBUSY;
6154 
6155 	rdev_for_each(rdev, mddev) {
6156 		sector_t avail = rdev->sectors;
6157 
6158 		if (fit && (num_sectors == 0 || num_sectors > avail))
6159 			num_sectors = avail;
6160 		if (avail < num_sectors)
6161 			return -ENOSPC;
6162 	}
6163 	rv = mddev->pers->resize(mddev, num_sectors);
6164 	if (!rv)
6165 		revalidate_disk(mddev->gendisk);
6166 	return rv;
6167 }
6168 
6169 static int update_raid_disks(struct mddev *mddev, int raid_disks)
6170 {
6171 	int rv;
6172 	struct md_rdev *rdev;
6173 	/* change the number of raid disks */
6174 	if (mddev->pers->check_reshape == NULL)
6175 		return -EINVAL;
6176 	if (raid_disks <= 0 ||
6177 	    (mddev->max_disks && raid_disks >= mddev->max_disks))
6178 		return -EINVAL;
6179 	if (mddev->sync_thread || mddev->reshape_position != MaxSector)
6180 		return -EBUSY;
6181 
6182 	rdev_for_each(rdev, mddev) {
6183 		if (mddev->raid_disks < raid_disks &&
6184 		    rdev->data_offset < rdev->new_data_offset)
6185 			return -EINVAL;
6186 		if (mddev->raid_disks > raid_disks &&
6187 		    rdev->data_offset > rdev->new_data_offset)
6188 			return -EINVAL;
6189 	}
6190 
6191 	mddev->delta_disks = raid_disks - mddev->raid_disks;
6192 	if (mddev->delta_disks < 0)
6193 		mddev->reshape_backwards = 1;
6194 	else if (mddev->delta_disks > 0)
6195 		mddev->reshape_backwards = 0;
6196 
6197 	rv = mddev->pers->check_reshape(mddev);
6198 	if (rv < 0) {
6199 		mddev->delta_disks = 0;
6200 		mddev->reshape_backwards = 0;
6201 	}
6202 	return rv;
6203 }
6204 
6205 
6206 /*
6207  * update_array_info is used to change the configuration of an
6208  * on-line array.
6209  * The version, ctime,level,size,raid_disks,not_persistent, layout,chunk_size
6210  * fields in the info are checked against the array.
6211  * Any differences that cannot be handled will cause an error.
6212  * Normally, only one change can be managed at a time.
6213  */
6214 static int update_array_info(struct mddev *mddev, mdu_array_info_t *info)
6215 {
6216 	int rv = 0;
6217 	int cnt = 0;
6218 	int state = 0;
6219 
6220 	/* calculate expected state,ignoring low bits */
6221 	if (mddev->bitmap && mddev->bitmap_info.offset)
6222 		state |= (1 << MD_SB_BITMAP_PRESENT);
6223 
6224 	if (mddev->major_version != info->major_version ||
6225 	    mddev->minor_version != info->minor_version ||
6226 /*	    mddev->patch_version != info->patch_version || */
6227 	    mddev->ctime         != info->ctime         ||
6228 	    mddev->level         != info->level         ||
6229 /*	    mddev->layout        != info->layout        || */
6230 	    !mddev->persistent	 != info->not_persistent||
6231 	    mddev->chunk_sectors != info->chunk_size >> 9 ||
6232 	    /* ignore bottom 8 bits of state, and allow SB_BITMAP_PRESENT to change */
6233 	    ((state^info->state) & 0xfffffe00)
6234 		)
6235 		return -EINVAL;
6236 	/* Check there is only one change */
6237 	if (info->size >= 0 && mddev->dev_sectors / 2 != info->size)
6238 		cnt++;
6239 	if (mddev->raid_disks != info->raid_disks)
6240 		cnt++;
6241 	if (mddev->layout != info->layout)
6242 		cnt++;
6243 	if ((state ^ info->state) & (1<<MD_SB_BITMAP_PRESENT))
6244 		cnt++;
6245 	if (cnt == 0)
6246 		return 0;
6247 	if (cnt > 1)
6248 		return -EINVAL;
6249 
6250 	if (mddev->layout != info->layout) {
6251 		/* Change layout
6252 		 * we don't need to do anything at the md level, the
6253 		 * personality will take care of it all.
6254 		 */
6255 		if (mddev->pers->check_reshape == NULL)
6256 			return -EINVAL;
6257 		else {
6258 			mddev->new_layout = info->layout;
6259 			rv = mddev->pers->check_reshape(mddev);
6260 			if (rv)
6261 				mddev->new_layout = mddev->layout;
6262 			return rv;
6263 		}
6264 	}
6265 	if (info->size >= 0 && mddev->dev_sectors / 2 != info->size)
6266 		rv = update_size(mddev, (sector_t)info->size * 2);
6267 
6268 	if (mddev->raid_disks    != info->raid_disks)
6269 		rv = update_raid_disks(mddev, info->raid_disks);
6270 
6271 	if ((state ^ info->state) & (1<<MD_SB_BITMAP_PRESENT)) {
6272 		if (mddev->pers->quiesce == NULL)
6273 			return -EINVAL;
6274 		if (mddev->recovery || mddev->sync_thread)
6275 			return -EBUSY;
6276 		if (info->state & (1<<MD_SB_BITMAP_PRESENT)) {
6277 			/* add the bitmap */
6278 			if (mddev->bitmap)
6279 				return -EEXIST;
6280 			if (mddev->bitmap_info.default_offset == 0)
6281 				return -EINVAL;
6282 			mddev->bitmap_info.offset =
6283 				mddev->bitmap_info.default_offset;
6284 			mddev->bitmap_info.space =
6285 				mddev->bitmap_info.default_space;
6286 			mddev->pers->quiesce(mddev, 1);
6287 			rv = bitmap_create(mddev);
6288 			if (!rv)
6289 				rv = bitmap_load(mddev);
6290 			if (rv)
6291 				bitmap_destroy(mddev);
6292 			mddev->pers->quiesce(mddev, 0);
6293 		} else {
6294 			/* remove the bitmap */
6295 			if (!mddev->bitmap)
6296 				return -ENOENT;
6297 			if (mddev->bitmap->storage.file)
6298 				return -EINVAL;
6299 			mddev->pers->quiesce(mddev, 1);
6300 			bitmap_destroy(mddev);
6301 			mddev->pers->quiesce(mddev, 0);
6302 			mddev->bitmap_info.offset = 0;
6303 		}
6304 	}
6305 	md_update_sb(mddev, 1);
6306 	return rv;
6307 }
6308 
6309 static int set_disk_faulty(struct mddev *mddev, dev_t dev)
6310 {
6311 	struct md_rdev *rdev;
6312 
6313 	if (mddev->pers == NULL)
6314 		return -ENODEV;
6315 
6316 	rdev = find_rdev(mddev, dev);
6317 	if (!rdev)
6318 		return -ENODEV;
6319 
6320 	md_error(mddev, rdev);
6321 	if (!test_bit(Faulty, &rdev->flags))
6322 		return -EBUSY;
6323 	return 0;
6324 }
6325 
6326 /*
6327  * We have a problem here : there is no easy way to give a CHS
6328  * virtual geometry. We currently pretend that we have a 2 heads
6329  * 4 sectors (with a BIG number of cylinders...). This drives
6330  * dosfs just mad... ;-)
6331  */
6332 static int md_getgeo(struct block_device *bdev, struct hd_geometry *geo)
6333 {
6334 	struct mddev *mddev = bdev->bd_disk->private_data;
6335 
6336 	geo->heads = 2;
6337 	geo->sectors = 4;
6338 	geo->cylinders = mddev->array_sectors / 8;
6339 	return 0;
6340 }
6341 
6342 static int md_ioctl(struct block_device *bdev, fmode_t mode,
6343 			unsigned int cmd, unsigned long arg)
6344 {
6345 	int err = 0;
6346 	void __user *argp = (void __user *)arg;
6347 	struct mddev *mddev = NULL;
6348 	int ro;
6349 
6350 	switch (cmd) {
6351 	case RAID_VERSION:
6352 	case GET_ARRAY_INFO:
6353 	case GET_DISK_INFO:
6354 		break;
6355 	default:
6356 		if (!capable(CAP_SYS_ADMIN))
6357 			return -EACCES;
6358 	}
6359 
6360 	/*
6361 	 * Commands dealing with the RAID driver but not any
6362 	 * particular array:
6363 	 */
6364 	switch (cmd)
6365 	{
6366 		case RAID_VERSION:
6367 			err = get_version(argp);
6368 			goto done;
6369 
6370 		case PRINT_RAID_DEBUG:
6371 			err = 0;
6372 			md_print_devices();
6373 			goto done;
6374 
6375 #ifndef MODULE
6376 		case RAID_AUTORUN:
6377 			err = 0;
6378 			autostart_arrays(arg);
6379 			goto done;
6380 #endif
6381 		default:;
6382 	}
6383 
6384 	/*
6385 	 * Commands creating/starting a new array:
6386 	 */
6387 
6388 	mddev = bdev->bd_disk->private_data;
6389 
6390 	if (!mddev) {
6391 		BUG();
6392 		goto abort;
6393 	}
6394 
6395 	err = mddev_lock(mddev);
6396 	if (err) {
6397 		printk(KERN_INFO
6398 			"md: ioctl lock interrupted, reason %d, cmd %d\n",
6399 			err, cmd);
6400 		goto abort;
6401 	}
6402 
6403 	switch (cmd)
6404 	{
6405 		case SET_ARRAY_INFO:
6406 			{
6407 				mdu_array_info_t info;
6408 				if (!arg)
6409 					memset(&info, 0, sizeof(info));
6410 				else if (copy_from_user(&info, argp, sizeof(info))) {
6411 					err = -EFAULT;
6412 					goto abort_unlock;
6413 				}
6414 				if (mddev->pers) {
6415 					err = update_array_info(mddev, &info);
6416 					if (err) {
6417 						printk(KERN_WARNING "md: couldn't update"
6418 						       " array info. %d\n", err);
6419 						goto abort_unlock;
6420 					}
6421 					goto done_unlock;
6422 				}
6423 				if (!list_empty(&mddev->disks)) {
6424 					printk(KERN_WARNING
6425 					       "md: array %s already has disks!\n",
6426 					       mdname(mddev));
6427 					err = -EBUSY;
6428 					goto abort_unlock;
6429 				}
6430 				if (mddev->raid_disks) {
6431 					printk(KERN_WARNING
6432 					       "md: array %s already initialised!\n",
6433 					       mdname(mddev));
6434 					err = -EBUSY;
6435 					goto abort_unlock;
6436 				}
6437 				err = set_array_info(mddev, &info);
6438 				if (err) {
6439 					printk(KERN_WARNING "md: couldn't set"
6440 					       " array info. %d\n", err);
6441 					goto abort_unlock;
6442 				}
6443 			}
6444 			goto done_unlock;
6445 
6446 		default:;
6447 	}
6448 
6449 	/*
6450 	 * Commands querying/configuring an existing array:
6451 	 */
6452 	/* if we are not initialised yet, only ADD_NEW_DISK, STOP_ARRAY,
6453 	 * RUN_ARRAY, and GET_ and SET_BITMAP_FILE are allowed */
6454 	if ((!mddev->raid_disks && !mddev->external)
6455 	    && cmd != ADD_NEW_DISK && cmd != STOP_ARRAY
6456 	    && cmd != RUN_ARRAY && cmd != SET_BITMAP_FILE
6457 	    && cmd != GET_BITMAP_FILE) {
6458 		err = -ENODEV;
6459 		goto abort_unlock;
6460 	}
6461 
6462 	/*
6463 	 * Commands even a read-only array can execute:
6464 	 */
6465 	switch (cmd)
6466 	{
6467 		case GET_ARRAY_INFO:
6468 			err = get_array_info(mddev, argp);
6469 			goto done_unlock;
6470 
6471 		case GET_BITMAP_FILE:
6472 			err = get_bitmap_file(mddev, argp);
6473 			goto done_unlock;
6474 
6475 		case GET_DISK_INFO:
6476 			err = get_disk_info(mddev, argp);
6477 			goto done_unlock;
6478 
6479 		case RESTART_ARRAY_RW:
6480 			err = restart_array(mddev);
6481 			goto done_unlock;
6482 
6483 		case STOP_ARRAY:
6484 			err = do_md_stop(mddev, 0, 1);
6485 			goto done_unlock;
6486 
6487 		case STOP_ARRAY_RO:
6488 			err = md_set_readonly(mddev, 1);
6489 			goto done_unlock;
6490 
6491 		case BLKROSET:
6492 			if (get_user(ro, (int __user *)(arg))) {
6493 				err = -EFAULT;
6494 				goto done_unlock;
6495 			}
6496 			err = -EINVAL;
6497 
6498 			/* if the bdev is going readonly the value of mddev->ro
6499 			 * does not matter, no writes are coming
6500 			 */
6501 			if (ro)
6502 				goto done_unlock;
6503 
6504 			/* are we are already prepared for writes? */
6505 			if (mddev->ro != 1)
6506 				goto done_unlock;
6507 
6508 			/* transitioning to readauto need only happen for
6509 			 * arrays that call md_write_start
6510 			 */
6511 			if (mddev->pers) {
6512 				err = restart_array(mddev);
6513 				if (err == 0) {
6514 					mddev->ro = 2;
6515 					set_disk_ro(mddev->gendisk, 0);
6516 				}
6517 			}
6518 			goto done_unlock;
6519 	}
6520 
6521 	/*
6522 	 * The remaining ioctls are changing the state of the
6523 	 * superblock, so we do not allow them on read-only arrays.
6524 	 * However non-MD ioctls (e.g. get-size) will still come through
6525 	 * here and hit the 'default' below, so only disallow
6526 	 * 'md' ioctls, and switch to rw mode if started auto-readonly.
6527 	 */
6528 	if (_IOC_TYPE(cmd) == MD_MAJOR && mddev->ro && mddev->pers) {
6529 		if (mddev->ro == 2) {
6530 			mddev->ro = 0;
6531 			sysfs_notify_dirent_safe(mddev->sysfs_state);
6532 			set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
6533 			md_wakeup_thread(mddev->thread);
6534 		} else {
6535 			err = -EROFS;
6536 			goto abort_unlock;
6537 		}
6538 	}
6539 
6540 	switch (cmd)
6541 	{
6542 		case ADD_NEW_DISK:
6543 		{
6544 			mdu_disk_info_t info;
6545 			if (copy_from_user(&info, argp, sizeof(info)))
6546 				err = -EFAULT;
6547 			else
6548 				err = add_new_disk(mddev, &info);
6549 			goto done_unlock;
6550 		}
6551 
6552 		case HOT_REMOVE_DISK:
6553 			err = hot_remove_disk(mddev, new_decode_dev(arg));
6554 			goto done_unlock;
6555 
6556 		case HOT_ADD_DISK:
6557 			err = hot_add_disk(mddev, new_decode_dev(arg));
6558 			goto done_unlock;
6559 
6560 		case SET_DISK_FAULTY:
6561 			err = set_disk_faulty(mddev, new_decode_dev(arg));
6562 			goto done_unlock;
6563 
6564 		case RUN_ARRAY:
6565 			err = do_md_run(mddev);
6566 			goto done_unlock;
6567 
6568 		case SET_BITMAP_FILE:
6569 			err = set_bitmap_file(mddev, (int)arg);
6570 			goto done_unlock;
6571 
6572 		default:
6573 			err = -EINVAL;
6574 			goto abort_unlock;
6575 	}
6576 
6577 done_unlock:
6578 abort_unlock:
6579 	if (mddev->hold_active == UNTIL_IOCTL &&
6580 	    err != -EINVAL)
6581 		mddev->hold_active = 0;
6582 	mddev_unlock(mddev);
6583 
6584 	return err;
6585 done:
6586 	if (err)
6587 		MD_BUG();
6588 abort:
6589 	return err;
6590 }
6591 #ifdef CONFIG_COMPAT
6592 static int md_compat_ioctl(struct block_device *bdev, fmode_t mode,
6593 		    unsigned int cmd, unsigned long arg)
6594 {
6595 	switch (cmd) {
6596 	case HOT_REMOVE_DISK:
6597 	case HOT_ADD_DISK:
6598 	case SET_DISK_FAULTY:
6599 	case SET_BITMAP_FILE:
6600 		/* These take in integer arg, do not convert */
6601 		break;
6602 	default:
6603 		arg = (unsigned long)compat_ptr(arg);
6604 		break;
6605 	}
6606 
6607 	return md_ioctl(bdev, mode, cmd, arg);
6608 }
6609 #endif /* CONFIG_COMPAT */
6610 
6611 static int md_open(struct block_device *bdev, fmode_t mode)
6612 {
6613 	/*
6614 	 * Succeed if we can lock the mddev, which confirms that
6615 	 * it isn't being stopped right now.
6616 	 */
6617 	struct mddev *mddev = mddev_find(bdev->bd_dev);
6618 	int err;
6619 
6620 	if (!mddev)
6621 		return -ENODEV;
6622 
6623 	if (mddev->gendisk != bdev->bd_disk) {
6624 		/* we are racing with mddev_put which is discarding this
6625 		 * bd_disk.
6626 		 */
6627 		mddev_put(mddev);
6628 		/* Wait until bdev->bd_disk is definitely gone */
6629 		flush_workqueue(md_misc_wq);
6630 		/* Then retry the open from the top */
6631 		return -ERESTARTSYS;
6632 	}
6633 	BUG_ON(mddev != bdev->bd_disk->private_data);
6634 
6635 	if ((err = mutex_lock_interruptible(&mddev->open_mutex)))
6636 		goto out;
6637 
6638 	err = 0;
6639 	atomic_inc(&mddev->openers);
6640 	mutex_unlock(&mddev->open_mutex);
6641 
6642 	check_disk_change(bdev);
6643  out:
6644 	return err;
6645 }
6646 
6647 static int md_release(struct gendisk *disk, fmode_t mode)
6648 {
6649  	struct mddev *mddev = disk->private_data;
6650 
6651 	BUG_ON(!mddev);
6652 	atomic_dec(&mddev->openers);
6653 	mddev_put(mddev);
6654 
6655 	return 0;
6656 }
6657 
6658 static int md_media_changed(struct gendisk *disk)
6659 {
6660 	struct mddev *mddev = disk->private_data;
6661 
6662 	return mddev->changed;
6663 }
6664 
6665 static int md_revalidate(struct gendisk *disk)
6666 {
6667 	struct mddev *mddev = disk->private_data;
6668 
6669 	mddev->changed = 0;
6670 	return 0;
6671 }
6672 static const struct block_device_operations md_fops =
6673 {
6674 	.owner		= THIS_MODULE,
6675 	.open		= md_open,
6676 	.release	= md_release,
6677 	.ioctl		= md_ioctl,
6678 #ifdef CONFIG_COMPAT
6679 	.compat_ioctl	= md_compat_ioctl,
6680 #endif
6681 	.getgeo		= md_getgeo,
6682 	.media_changed  = md_media_changed,
6683 	.revalidate_disk= md_revalidate,
6684 };
6685 
6686 static int md_thread(void * arg)
6687 {
6688 	struct md_thread *thread = arg;
6689 
6690 	/*
6691 	 * md_thread is a 'system-thread', it's priority should be very
6692 	 * high. We avoid resource deadlocks individually in each
6693 	 * raid personality. (RAID5 does preallocation) We also use RR and
6694 	 * the very same RT priority as kswapd, thus we will never get
6695 	 * into a priority inversion deadlock.
6696 	 *
6697 	 * we definitely have to have equal or higher priority than
6698 	 * bdflush, otherwise bdflush will deadlock if there are too
6699 	 * many dirty RAID5 blocks.
6700 	 */
6701 
6702 	allow_signal(SIGKILL);
6703 	while (!kthread_should_stop()) {
6704 
6705 		/* We need to wait INTERRUPTIBLE so that
6706 		 * we don't add to the load-average.
6707 		 * That means we need to be sure no signals are
6708 		 * pending
6709 		 */
6710 		if (signal_pending(current))
6711 			flush_signals(current);
6712 
6713 		wait_event_interruptible_timeout
6714 			(thread->wqueue,
6715 			 test_bit(THREAD_WAKEUP, &thread->flags)
6716 			 || kthread_should_stop(),
6717 			 thread->timeout);
6718 
6719 		clear_bit(THREAD_WAKEUP, &thread->flags);
6720 		if (!kthread_should_stop())
6721 			thread->run(thread->mddev);
6722 	}
6723 
6724 	return 0;
6725 }
6726 
6727 void md_wakeup_thread(struct md_thread *thread)
6728 {
6729 	if (thread) {
6730 		pr_debug("md: waking up MD thread %s.\n", thread->tsk->comm);
6731 		set_bit(THREAD_WAKEUP, &thread->flags);
6732 		wake_up(&thread->wqueue);
6733 	}
6734 }
6735 
6736 struct md_thread *md_register_thread(void (*run) (struct mddev *), struct mddev *mddev,
6737 				 const char *name)
6738 {
6739 	struct md_thread *thread;
6740 
6741 	thread = kzalloc(sizeof(struct md_thread), GFP_KERNEL);
6742 	if (!thread)
6743 		return NULL;
6744 
6745 	init_waitqueue_head(&thread->wqueue);
6746 
6747 	thread->run = run;
6748 	thread->mddev = mddev;
6749 	thread->timeout = MAX_SCHEDULE_TIMEOUT;
6750 	thread->tsk = kthread_run(md_thread, thread,
6751 				  "%s_%s",
6752 				  mdname(thread->mddev),
6753 				  name);
6754 	if (IS_ERR(thread->tsk)) {
6755 		kfree(thread);
6756 		return NULL;
6757 	}
6758 	return thread;
6759 }
6760 
6761 void md_unregister_thread(struct md_thread **threadp)
6762 {
6763 	struct md_thread *thread = *threadp;
6764 	if (!thread)
6765 		return;
6766 	pr_debug("interrupting MD-thread pid %d\n", task_pid_nr(thread->tsk));
6767 	/* Locking ensures that mddev_unlock does not wake_up a
6768 	 * non-existent thread
6769 	 */
6770 	spin_lock(&pers_lock);
6771 	*threadp = NULL;
6772 	spin_unlock(&pers_lock);
6773 
6774 	kthread_stop(thread->tsk);
6775 	kfree(thread);
6776 }
6777 
6778 void md_error(struct mddev *mddev, struct md_rdev *rdev)
6779 {
6780 	if (!mddev) {
6781 		MD_BUG();
6782 		return;
6783 	}
6784 
6785 	if (!rdev || test_bit(Faulty, &rdev->flags))
6786 		return;
6787 
6788 	if (!mddev->pers || !mddev->pers->error_handler)
6789 		return;
6790 	mddev->pers->error_handler(mddev,rdev);
6791 	if (mddev->degraded)
6792 		set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
6793 	sysfs_notify_dirent_safe(rdev->sysfs_state);
6794 	set_bit(MD_RECOVERY_INTR, &mddev->recovery);
6795 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
6796 	md_wakeup_thread(mddev->thread);
6797 	if (mddev->event_work.func)
6798 		queue_work(md_misc_wq, &mddev->event_work);
6799 	md_new_event_inintr(mddev);
6800 }
6801 
6802 /* seq_file implementation /proc/mdstat */
6803 
6804 static void status_unused(struct seq_file *seq)
6805 {
6806 	int i = 0;
6807 	struct md_rdev *rdev;
6808 
6809 	seq_printf(seq, "unused devices: ");
6810 
6811 	list_for_each_entry(rdev, &pending_raid_disks, same_set) {
6812 		char b[BDEVNAME_SIZE];
6813 		i++;
6814 		seq_printf(seq, "%s ",
6815 			      bdevname(rdev->bdev,b));
6816 	}
6817 	if (!i)
6818 		seq_printf(seq, "<none>");
6819 
6820 	seq_printf(seq, "\n");
6821 }
6822 
6823 
6824 static void status_resync(struct seq_file *seq, struct mddev * mddev)
6825 {
6826 	sector_t max_sectors, resync, res;
6827 	unsigned long dt, db;
6828 	sector_t rt;
6829 	int scale;
6830 	unsigned int per_milli;
6831 
6832 	resync = mddev->curr_resync - atomic_read(&mddev->recovery_active);
6833 
6834 	if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) ||
6835 	    test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
6836 		max_sectors = mddev->resync_max_sectors;
6837 	else
6838 		max_sectors = mddev->dev_sectors;
6839 
6840 	/*
6841 	 * Should not happen.
6842 	 */
6843 	if (!max_sectors) {
6844 		MD_BUG();
6845 		return;
6846 	}
6847 	/* Pick 'scale' such that (resync>>scale)*1000 will fit
6848 	 * in a sector_t, and (max_sectors>>scale) will fit in a
6849 	 * u32, as those are the requirements for sector_div.
6850 	 * Thus 'scale' must be at least 10
6851 	 */
6852 	scale = 10;
6853 	if (sizeof(sector_t) > sizeof(unsigned long)) {
6854 		while ( max_sectors/2 > (1ULL<<(scale+32)))
6855 			scale++;
6856 	}
6857 	res = (resync>>scale)*1000;
6858 	sector_div(res, (u32)((max_sectors>>scale)+1));
6859 
6860 	per_milli = res;
6861 	{
6862 		int i, x = per_milli/50, y = 20-x;
6863 		seq_printf(seq, "[");
6864 		for (i = 0; i < x; i++)
6865 			seq_printf(seq, "=");
6866 		seq_printf(seq, ">");
6867 		for (i = 0; i < y; i++)
6868 			seq_printf(seq, ".");
6869 		seq_printf(seq, "] ");
6870 	}
6871 	seq_printf(seq, " %s =%3u.%u%% (%llu/%llu)",
6872 		   (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)?
6873 		    "reshape" :
6874 		    (test_bit(MD_RECOVERY_CHECK, &mddev->recovery)?
6875 		     "check" :
6876 		     (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) ?
6877 		      "resync" : "recovery"))),
6878 		   per_milli/10, per_milli % 10,
6879 		   (unsigned long long) resync/2,
6880 		   (unsigned long long) max_sectors/2);
6881 
6882 	/*
6883 	 * dt: time from mark until now
6884 	 * db: blocks written from mark until now
6885 	 * rt: remaining time
6886 	 *
6887 	 * rt is a sector_t, so could be 32bit or 64bit.
6888 	 * So we divide before multiply in case it is 32bit and close
6889 	 * to the limit.
6890 	 * We scale the divisor (db) by 32 to avoid losing precision
6891 	 * near the end of resync when the number of remaining sectors
6892 	 * is close to 'db'.
6893 	 * We then divide rt by 32 after multiplying by db to compensate.
6894 	 * The '+1' avoids division by zero if db is very small.
6895 	 */
6896 	dt = ((jiffies - mddev->resync_mark) / HZ);
6897 	if (!dt) dt++;
6898 	db = (mddev->curr_mark_cnt - atomic_read(&mddev->recovery_active))
6899 		- mddev->resync_mark_cnt;
6900 
6901 	rt = max_sectors - resync;    /* number of remaining sectors */
6902 	sector_div(rt, db/32+1);
6903 	rt *= dt;
6904 	rt >>= 5;
6905 
6906 	seq_printf(seq, " finish=%lu.%lumin", (unsigned long)rt / 60,
6907 		   ((unsigned long)rt % 60)/6);
6908 
6909 	seq_printf(seq, " speed=%ldK/sec", db/2/dt);
6910 }
6911 
6912 static void *md_seq_start(struct seq_file *seq, loff_t *pos)
6913 {
6914 	struct list_head *tmp;
6915 	loff_t l = *pos;
6916 	struct mddev *mddev;
6917 
6918 	if (l >= 0x10000)
6919 		return NULL;
6920 	if (!l--)
6921 		/* header */
6922 		return (void*)1;
6923 
6924 	spin_lock(&all_mddevs_lock);
6925 	list_for_each(tmp,&all_mddevs)
6926 		if (!l--) {
6927 			mddev = list_entry(tmp, struct mddev, all_mddevs);
6928 			mddev_get(mddev);
6929 			spin_unlock(&all_mddevs_lock);
6930 			return mddev;
6931 		}
6932 	spin_unlock(&all_mddevs_lock);
6933 	if (!l--)
6934 		return (void*)2;/* tail */
6935 	return NULL;
6936 }
6937 
6938 static void *md_seq_next(struct seq_file *seq, void *v, loff_t *pos)
6939 {
6940 	struct list_head *tmp;
6941 	struct mddev *next_mddev, *mddev = v;
6942 
6943 	++*pos;
6944 	if (v == (void*)2)
6945 		return NULL;
6946 
6947 	spin_lock(&all_mddevs_lock);
6948 	if (v == (void*)1)
6949 		tmp = all_mddevs.next;
6950 	else
6951 		tmp = mddev->all_mddevs.next;
6952 	if (tmp != &all_mddevs)
6953 		next_mddev = mddev_get(list_entry(tmp,struct mddev,all_mddevs));
6954 	else {
6955 		next_mddev = (void*)2;
6956 		*pos = 0x10000;
6957 	}
6958 	spin_unlock(&all_mddevs_lock);
6959 
6960 	if (v != (void*)1)
6961 		mddev_put(mddev);
6962 	return next_mddev;
6963 
6964 }
6965 
6966 static void md_seq_stop(struct seq_file *seq, void *v)
6967 {
6968 	struct mddev *mddev = v;
6969 
6970 	if (mddev && v != (void*)1 && v != (void*)2)
6971 		mddev_put(mddev);
6972 }
6973 
6974 static int md_seq_show(struct seq_file *seq, void *v)
6975 {
6976 	struct mddev *mddev = v;
6977 	sector_t sectors;
6978 	struct md_rdev *rdev;
6979 
6980 	if (v == (void*)1) {
6981 		struct md_personality *pers;
6982 		seq_printf(seq, "Personalities : ");
6983 		spin_lock(&pers_lock);
6984 		list_for_each_entry(pers, &pers_list, list)
6985 			seq_printf(seq, "[%s] ", pers->name);
6986 
6987 		spin_unlock(&pers_lock);
6988 		seq_printf(seq, "\n");
6989 		seq->poll_event = atomic_read(&md_event_count);
6990 		return 0;
6991 	}
6992 	if (v == (void*)2) {
6993 		status_unused(seq);
6994 		return 0;
6995 	}
6996 
6997 	if (mddev_lock(mddev) < 0)
6998 		return -EINTR;
6999 
7000 	if (mddev->pers || mddev->raid_disks || !list_empty(&mddev->disks)) {
7001 		seq_printf(seq, "%s : %sactive", mdname(mddev),
7002 						mddev->pers ? "" : "in");
7003 		if (mddev->pers) {
7004 			if (mddev->ro==1)
7005 				seq_printf(seq, " (read-only)");
7006 			if (mddev->ro==2)
7007 				seq_printf(seq, " (auto-read-only)");
7008 			seq_printf(seq, " %s", mddev->pers->name);
7009 		}
7010 
7011 		sectors = 0;
7012 		rdev_for_each(rdev, mddev) {
7013 			char b[BDEVNAME_SIZE];
7014 			seq_printf(seq, " %s[%d]",
7015 				bdevname(rdev->bdev,b), rdev->desc_nr);
7016 			if (test_bit(WriteMostly, &rdev->flags))
7017 				seq_printf(seq, "(W)");
7018 			if (test_bit(Faulty, &rdev->flags)) {
7019 				seq_printf(seq, "(F)");
7020 				continue;
7021 			}
7022 			if (rdev->raid_disk < 0)
7023 				seq_printf(seq, "(S)"); /* spare */
7024 			if (test_bit(Replacement, &rdev->flags))
7025 				seq_printf(seq, "(R)");
7026 			sectors += rdev->sectors;
7027 		}
7028 
7029 		if (!list_empty(&mddev->disks)) {
7030 			if (mddev->pers)
7031 				seq_printf(seq, "\n      %llu blocks",
7032 					   (unsigned long long)
7033 					   mddev->array_sectors / 2);
7034 			else
7035 				seq_printf(seq, "\n      %llu blocks",
7036 					   (unsigned long long)sectors / 2);
7037 		}
7038 		if (mddev->persistent) {
7039 			if (mddev->major_version != 0 ||
7040 			    mddev->minor_version != 90) {
7041 				seq_printf(seq," super %d.%d",
7042 					   mddev->major_version,
7043 					   mddev->minor_version);
7044 			}
7045 		} else if (mddev->external)
7046 			seq_printf(seq, " super external:%s",
7047 				   mddev->metadata_type);
7048 		else
7049 			seq_printf(seq, " super non-persistent");
7050 
7051 		if (mddev->pers) {
7052 			mddev->pers->status(seq, mddev);
7053 	 		seq_printf(seq, "\n      ");
7054 			if (mddev->pers->sync_request) {
7055 				if (mddev->curr_resync > 2) {
7056 					status_resync(seq, mddev);
7057 					seq_printf(seq, "\n      ");
7058 				} else if (mddev->curr_resync == 1 || mddev->curr_resync == 2)
7059 					seq_printf(seq, "\tresync=DELAYED\n      ");
7060 				else if (mddev->recovery_cp < MaxSector)
7061 					seq_printf(seq, "\tresync=PENDING\n      ");
7062 			}
7063 		} else
7064 			seq_printf(seq, "\n       ");
7065 
7066 		bitmap_status(seq, mddev->bitmap);
7067 
7068 		seq_printf(seq, "\n");
7069 	}
7070 	mddev_unlock(mddev);
7071 
7072 	return 0;
7073 }
7074 
7075 static const struct seq_operations md_seq_ops = {
7076 	.start  = md_seq_start,
7077 	.next   = md_seq_next,
7078 	.stop   = md_seq_stop,
7079 	.show   = md_seq_show,
7080 };
7081 
7082 static int md_seq_open(struct inode *inode, struct file *file)
7083 {
7084 	struct seq_file *seq;
7085 	int error;
7086 
7087 	error = seq_open(file, &md_seq_ops);
7088 	if (error)
7089 		return error;
7090 
7091 	seq = file->private_data;
7092 	seq->poll_event = atomic_read(&md_event_count);
7093 	return error;
7094 }
7095 
7096 static unsigned int mdstat_poll(struct file *filp, poll_table *wait)
7097 {
7098 	struct seq_file *seq = filp->private_data;
7099 	int mask;
7100 
7101 	poll_wait(filp, &md_event_waiters, wait);
7102 
7103 	/* always allow read */
7104 	mask = POLLIN | POLLRDNORM;
7105 
7106 	if (seq->poll_event != atomic_read(&md_event_count))
7107 		mask |= POLLERR | POLLPRI;
7108 	return mask;
7109 }
7110 
7111 static const struct file_operations md_seq_fops = {
7112 	.owner		= THIS_MODULE,
7113 	.open           = md_seq_open,
7114 	.read           = seq_read,
7115 	.llseek         = seq_lseek,
7116 	.release	= seq_release_private,
7117 	.poll		= mdstat_poll,
7118 };
7119 
7120 int register_md_personality(struct md_personality *p)
7121 {
7122 	spin_lock(&pers_lock);
7123 	list_add_tail(&p->list, &pers_list);
7124 	printk(KERN_INFO "md: %s personality registered for level %d\n", p->name, p->level);
7125 	spin_unlock(&pers_lock);
7126 	return 0;
7127 }
7128 
7129 int unregister_md_personality(struct md_personality *p)
7130 {
7131 	printk(KERN_INFO "md: %s personality unregistered\n", p->name);
7132 	spin_lock(&pers_lock);
7133 	list_del_init(&p->list);
7134 	spin_unlock(&pers_lock);
7135 	return 0;
7136 }
7137 
7138 static int is_mddev_idle(struct mddev *mddev, int init)
7139 {
7140 	struct md_rdev * rdev;
7141 	int idle;
7142 	int curr_events;
7143 
7144 	idle = 1;
7145 	rcu_read_lock();
7146 	rdev_for_each_rcu(rdev, mddev) {
7147 		struct gendisk *disk = rdev->bdev->bd_contains->bd_disk;
7148 		curr_events = (int)part_stat_read(&disk->part0, sectors[0]) +
7149 			      (int)part_stat_read(&disk->part0, sectors[1]) -
7150 			      atomic_read(&disk->sync_io);
7151 		/* sync IO will cause sync_io to increase before the disk_stats
7152 		 * as sync_io is counted when a request starts, and
7153 		 * disk_stats is counted when it completes.
7154 		 * So resync activity will cause curr_events to be smaller than
7155 		 * when there was no such activity.
7156 		 * non-sync IO will cause disk_stat to increase without
7157 		 * increasing sync_io so curr_events will (eventually)
7158 		 * be larger than it was before.  Once it becomes
7159 		 * substantially larger, the test below will cause
7160 		 * the array to appear non-idle, and resync will slow
7161 		 * down.
7162 		 * If there is a lot of outstanding resync activity when
7163 		 * we set last_event to curr_events, then all that activity
7164 		 * completing might cause the array to appear non-idle
7165 		 * and resync will be slowed down even though there might
7166 		 * not have been non-resync activity.  This will only
7167 		 * happen once though.  'last_events' will soon reflect
7168 		 * the state where there is little or no outstanding
7169 		 * resync requests, and further resync activity will
7170 		 * always make curr_events less than last_events.
7171 		 *
7172 		 */
7173 		if (init || curr_events - rdev->last_events > 64) {
7174 			rdev->last_events = curr_events;
7175 			idle = 0;
7176 		}
7177 	}
7178 	rcu_read_unlock();
7179 	return idle;
7180 }
7181 
7182 void md_done_sync(struct mddev *mddev, int blocks, int ok)
7183 {
7184 	/* another "blocks" (512byte) blocks have been synced */
7185 	atomic_sub(blocks, &mddev->recovery_active);
7186 	wake_up(&mddev->recovery_wait);
7187 	if (!ok) {
7188 		set_bit(MD_RECOVERY_INTR, &mddev->recovery);
7189 		md_wakeup_thread(mddev->thread);
7190 		// stop recovery, signal do_sync ....
7191 	}
7192 }
7193 
7194 
7195 /* md_write_start(mddev, bi)
7196  * If we need to update some array metadata (e.g. 'active' flag
7197  * in superblock) before writing, schedule a superblock update
7198  * and wait for it to complete.
7199  */
7200 void md_write_start(struct mddev *mddev, struct bio *bi)
7201 {
7202 	int did_change = 0;
7203 	if (bio_data_dir(bi) != WRITE)
7204 		return;
7205 
7206 	BUG_ON(mddev->ro == 1);
7207 	if (mddev->ro == 2) {
7208 		/* need to switch to read/write */
7209 		mddev->ro = 0;
7210 		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
7211 		md_wakeup_thread(mddev->thread);
7212 		md_wakeup_thread(mddev->sync_thread);
7213 		did_change = 1;
7214 	}
7215 	atomic_inc(&mddev->writes_pending);
7216 	if (mddev->safemode == 1)
7217 		mddev->safemode = 0;
7218 	if (mddev->in_sync) {
7219 		spin_lock_irq(&mddev->write_lock);
7220 		if (mddev->in_sync) {
7221 			mddev->in_sync = 0;
7222 			set_bit(MD_CHANGE_CLEAN, &mddev->flags);
7223 			set_bit(MD_CHANGE_PENDING, &mddev->flags);
7224 			md_wakeup_thread(mddev->thread);
7225 			did_change = 1;
7226 		}
7227 		spin_unlock_irq(&mddev->write_lock);
7228 	}
7229 	if (did_change)
7230 		sysfs_notify_dirent_safe(mddev->sysfs_state);
7231 	wait_event(mddev->sb_wait,
7232 		   !test_bit(MD_CHANGE_PENDING, &mddev->flags));
7233 }
7234 
7235 void md_write_end(struct mddev *mddev)
7236 {
7237 	if (atomic_dec_and_test(&mddev->writes_pending)) {
7238 		if (mddev->safemode == 2)
7239 			md_wakeup_thread(mddev->thread);
7240 		else if (mddev->safemode_delay)
7241 			mod_timer(&mddev->safemode_timer, jiffies + mddev->safemode_delay);
7242 	}
7243 }
7244 
7245 /* md_allow_write(mddev)
7246  * Calling this ensures that the array is marked 'active' so that writes
7247  * may proceed without blocking.  It is important to call this before
7248  * attempting a GFP_KERNEL allocation while holding the mddev lock.
7249  * Must be called with mddev_lock held.
7250  *
7251  * In the ->external case MD_CHANGE_CLEAN can not be cleared until mddev->lock
7252  * is dropped, so return -EAGAIN after notifying userspace.
7253  */
7254 int md_allow_write(struct mddev *mddev)
7255 {
7256 	if (!mddev->pers)
7257 		return 0;
7258 	if (mddev->ro)
7259 		return 0;
7260 	if (!mddev->pers->sync_request)
7261 		return 0;
7262 
7263 	spin_lock_irq(&mddev->write_lock);
7264 	if (mddev->in_sync) {
7265 		mddev->in_sync = 0;
7266 		set_bit(MD_CHANGE_CLEAN, &mddev->flags);
7267 		set_bit(MD_CHANGE_PENDING, &mddev->flags);
7268 		if (mddev->safemode_delay &&
7269 		    mddev->safemode == 0)
7270 			mddev->safemode = 1;
7271 		spin_unlock_irq(&mddev->write_lock);
7272 		md_update_sb(mddev, 0);
7273 		sysfs_notify_dirent_safe(mddev->sysfs_state);
7274 	} else
7275 		spin_unlock_irq(&mddev->write_lock);
7276 
7277 	if (test_bit(MD_CHANGE_PENDING, &mddev->flags))
7278 		return -EAGAIN;
7279 	else
7280 		return 0;
7281 }
7282 EXPORT_SYMBOL_GPL(md_allow_write);
7283 
7284 #define SYNC_MARKS	10
7285 #define	SYNC_MARK_STEP	(3*HZ)
7286 void md_do_sync(struct mddev *mddev)
7287 {
7288 	struct mddev *mddev2;
7289 	unsigned int currspeed = 0,
7290 		 window;
7291 	sector_t max_sectors,j, io_sectors;
7292 	unsigned long mark[SYNC_MARKS];
7293 	sector_t mark_cnt[SYNC_MARKS];
7294 	int last_mark,m;
7295 	struct list_head *tmp;
7296 	sector_t last_check;
7297 	int skipped = 0;
7298 	struct md_rdev *rdev;
7299 	char *desc;
7300 	struct blk_plug plug;
7301 
7302 	/* just incase thread restarts... */
7303 	if (test_bit(MD_RECOVERY_DONE, &mddev->recovery))
7304 		return;
7305 	if (mddev->ro) /* never try to sync a read-only array */
7306 		return;
7307 
7308 	if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
7309 		if (test_bit(MD_RECOVERY_CHECK, &mddev->recovery))
7310 			desc = "data-check";
7311 		else if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
7312 			desc = "requested-resync";
7313 		else
7314 			desc = "resync";
7315 	} else if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
7316 		desc = "reshape";
7317 	else
7318 		desc = "recovery";
7319 
7320 	/* we overload curr_resync somewhat here.
7321 	 * 0 == not engaged in resync at all
7322 	 * 2 == checking that there is no conflict with another sync
7323 	 * 1 == like 2, but have yielded to allow conflicting resync to
7324 	 *		commense
7325 	 * other == active in resync - this many blocks
7326 	 *
7327 	 * Before starting a resync we must have set curr_resync to
7328 	 * 2, and then checked that every "conflicting" array has curr_resync
7329 	 * less than ours.  When we find one that is the same or higher
7330 	 * we wait on resync_wait.  To avoid deadlock, we reduce curr_resync
7331 	 * to 1 if we choose to yield (based arbitrarily on address of mddev structure).
7332 	 * This will mean we have to start checking from the beginning again.
7333 	 *
7334 	 */
7335 
7336 	do {
7337 		mddev->curr_resync = 2;
7338 
7339 	try_again:
7340 		if (kthread_should_stop())
7341 			set_bit(MD_RECOVERY_INTR, &mddev->recovery);
7342 
7343 		if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
7344 			goto skip;
7345 		for_each_mddev(mddev2, tmp) {
7346 			if (mddev2 == mddev)
7347 				continue;
7348 			if (!mddev->parallel_resync
7349 			&&  mddev2->curr_resync
7350 			&&  match_mddev_units(mddev, mddev2)) {
7351 				DEFINE_WAIT(wq);
7352 				if (mddev < mddev2 && mddev->curr_resync == 2) {
7353 					/* arbitrarily yield */
7354 					mddev->curr_resync = 1;
7355 					wake_up(&resync_wait);
7356 				}
7357 				if (mddev > mddev2 && mddev->curr_resync == 1)
7358 					/* no need to wait here, we can wait the next
7359 					 * time 'round when curr_resync == 2
7360 					 */
7361 					continue;
7362 				/* We need to wait 'interruptible' so as not to
7363 				 * contribute to the load average, and not to
7364 				 * be caught by 'softlockup'
7365 				 */
7366 				prepare_to_wait(&resync_wait, &wq, TASK_INTERRUPTIBLE);
7367 				if (!kthread_should_stop() &&
7368 				    mddev2->curr_resync >= mddev->curr_resync) {
7369 					printk(KERN_INFO "md: delaying %s of %s"
7370 					       " until %s has finished (they"
7371 					       " share one or more physical units)\n",
7372 					       desc, mdname(mddev), mdname(mddev2));
7373 					mddev_put(mddev2);
7374 					if (signal_pending(current))
7375 						flush_signals(current);
7376 					schedule();
7377 					finish_wait(&resync_wait, &wq);
7378 					goto try_again;
7379 				}
7380 				finish_wait(&resync_wait, &wq);
7381 			}
7382 		}
7383 	} while (mddev->curr_resync < 2);
7384 
7385 	j = 0;
7386 	if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
7387 		/* resync follows the size requested by the personality,
7388 		 * which defaults to physical size, but can be virtual size
7389 		 */
7390 		max_sectors = mddev->resync_max_sectors;
7391 		mddev->resync_mismatches = 0;
7392 		/* we don't use the checkpoint if there's a bitmap */
7393 		if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
7394 			j = mddev->resync_min;
7395 		else if (!mddev->bitmap)
7396 			j = mddev->recovery_cp;
7397 
7398 	} else if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
7399 		max_sectors = mddev->resync_max_sectors;
7400 	else {
7401 		/* recovery follows the physical size of devices */
7402 		max_sectors = mddev->dev_sectors;
7403 		j = MaxSector;
7404 		rcu_read_lock();
7405 		rdev_for_each_rcu(rdev, mddev)
7406 			if (rdev->raid_disk >= 0 &&
7407 			    !test_bit(Faulty, &rdev->flags) &&
7408 			    !test_bit(In_sync, &rdev->flags) &&
7409 			    rdev->recovery_offset < j)
7410 				j = rdev->recovery_offset;
7411 		rcu_read_unlock();
7412 	}
7413 
7414 	printk(KERN_INFO "md: %s of RAID array %s\n", desc, mdname(mddev));
7415 	printk(KERN_INFO "md: minimum _guaranteed_  speed:"
7416 		" %d KB/sec/disk.\n", speed_min(mddev));
7417 	printk(KERN_INFO "md: using maximum available idle IO bandwidth "
7418 	       "(but not more than %d KB/sec) for %s.\n",
7419 	       speed_max(mddev), desc);
7420 
7421 	is_mddev_idle(mddev, 1); /* this initializes IO event counters */
7422 
7423 	io_sectors = 0;
7424 	for (m = 0; m < SYNC_MARKS; m++) {
7425 		mark[m] = jiffies;
7426 		mark_cnt[m] = io_sectors;
7427 	}
7428 	last_mark = 0;
7429 	mddev->resync_mark = mark[last_mark];
7430 	mddev->resync_mark_cnt = mark_cnt[last_mark];
7431 
7432 	/*
7433 	 * Tune reconstruction:
7434 	 */
7435 	window = 32*(PAGE_SIZE/512);
7436 	printk(KERN_INFO "md: using %dk window, over a total of %lluk.\n",
7437 		window/2, (unsigned long long)max_sectors/2);
7438 
7439 	atomic_set(&mddev->recovery_active, 0);
7440 	last_check = 0;
7441 
7442 	if (j>2) {
7443 		printk(KERN_INFO
7444 		       "md: resuming %s of %s from checkpoint.\n",
7445 		       desc, mdname(mddev));
7446 		mddev->curr_resync = j;
7447 	}
7448 	mddev->curr_resync_completed = j;
7449 
7450 	blk_start_plug(&plug);
7451 	while (j < max_sectors) {
7452 		sector_t sectors;
7453 
7454 		skipped = 0;
7455 
7456 		if (!test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
7457 		    ((mddev->curr_resync > mddev->curr_resync_completed &&
7458 		      (mddev->curr_resync - mddev->curr_resync_completed)
7459 		      > (max_sectors >> 4)) ||
7460 		     (j - mddev->curr_resync_completed)*2
7461 		     >= mddev->resync_max - mddev->curr_resync_completed
7462 			    )) {
7463 			/* time to update curr_resync_completed */
7464 			wait_event(mddev->recovery_wait,
7465 				   atomic_read(&mddev->recovery_active) == 0);
7466 			mddev->curr_resync_completed = j;
7467 			set_bit(MD_CHANGE_CLEAN, &mddev->flags);
7468 			sysfs_notify(&mddev->kobj, NULL, "sync_completed");
7469 		}
7470 
7471 		while (j >= mddev->resync_max && !kthread_should_stop()) {
7472 			/* As this condition is controlled by user-space,
7473 			 * we can block indefinitely, so use '_interruptible'
7474 			 * to avoid triggering warnings.
7475 			 */
7476 			flush_signals(current); /* just in case */
7477 			wait_event_interruptible(mddev->recovery_wait,
7478 						 mddev->resync_max > j
7479 						 || kthread_should_stop());
7480 		}
7481 
7482 		if (kthread_should_stop())
7483 			goto interrupted;
7484 
7485 		sectors = mddev->pers->sync_request(mddev, j, &skipped,
7486 						  currspeed < speed_min(mddev));
7487 		if (sectors == 0) {
7488 			set_bit(MD_RECOVERY_INTR, &mddev->recovery);
7489 			goto out;
7490 		}
7491 
7492 		if (!skipped) { /* actual IO requested */
7493 			io_sectors += sectors;
7494 			atomic_add(sectors, &mddev->recovery_active);
7495 		}
7496 
7497 		if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
7498 			break;
7499 
7500 		j += sectors;
7501 		if (j>1) mddev->curr_resync = j;
7502 		mddev->curr_mark_cnt = io_sectors;
7503 		if (last_check == 0)
7504 			/* this is the earliest that rebuild will be
7505 			 * visible in /proc/mdstat
7506 			 */
7507 			md_new_event(mddev);
7508 
7509 		if (last_check + window > io_sectors || j == max_sectors)
7510 			continue;
7511 
7512 		last_check = io_sectors;
7513 	repeat:
7514 		if (time_after_eq(jiffies, mark[last_mark] + SYNC_MARK_STEP )) {
7515 			/* step marks */
7516 			int next = (last_mark+1) % SYNC_MARKS;
7517 
7518 			mddev->resync_mark = mark[next];
7519 			mddev->resync_mark_cnt = mark_cnt[next];
7520 			mark[next] = jiffies;
7521 			mark_cnt[next] = io_sectors - atomic_read(&mddev->recovery_active);
7522 			last_mark = next;
7523 		}
7524 
7525 
7526 		if (kthread_should_stop())
7527 			goto interrupted;
7528 
7529 
7530 		/*
7531 		 * this loop exits only if either when we are slower than
7532 		 * the 'hard' speed limit, or the system was IO-idle for
7533 		 * a jiffy.
7534 		 * the system might be non-idle CPU-wise, but we only care
7535 		 * about not overloading the IO subsystem. (things like an
7536 		 * e2fsck being done on the RAID array should execute fast)
7537 		 */
7538 		cond_resched();
7539 
7540 		currspeed = ((unsigned long)(io_sectors-mddev->resync_mark_cnt))/2
7541 			/((jiffies-mddev->resync_mark)/HZ +1) +1;
7542 
7543 		if (currspeed > speed_min(mddev)) {
7544 			if ((currspeed > speed_max(mddev)) ||
7545 					!is_mddev_idle(mddev, 0)) {
7546 				msleep(500);
7547 				goto repeat;
7548 			}
7549 		}
7550 	}
7551 	printk(KERN_INFO "md: %s: %s done.\n",mdname(mddev), desc);
7552 	/*
7553 	 * this also signals 'finished resyncing' to md_stop
7554 	 */
7555  out:
7556 	blk_finish_plug(&plug);
7557 	wait_event(mddev->recovery_wait, !atomic_read(&mddev->recovery_active));
7558 
7559 	/* tell personality that we are finished */
7560 	mddev->pers->sync_request(mddev, max_sectors, &skipped, 1);
7561 
7562 	if (!test_bit(MD_RECOVERY_CHECK, &mddev->recovery) &&
7563 	    mddev->curr_resync > 2) {
7564 		if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
7565 			if (test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
7566 				if (mddev->curr_resync >= mddev->recovery_cp) {
7567 					printk(KERN_INFO
7568 					       "md: checkpointing %s of %s.\n",
7569 					       desc, mdname(mddev));
7570 					mddev->recovery_cp =
7571 						mddev->curr_resync_completed;
7572 				}
7573 			} else
7574 				mddev->recovery_cp = MaxSector;
7575 		} else {
7576 			if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery))
7577 				mddev->curr_resync = MaxSector;
7578 			rcu_read_lock();
7579 			rdev_for_each_rcu(rdev, mddev)
7580 				if (rdev->raid_disk >= 0 &&
7581 				    mddev->delta_disks >= 0 &&
7582 				    !test_bit(Faulty, &rdev->flags) &&
7583 				    !test_bit(In_sync, &rdev->flags) &&
7584 				    rdev->recovery_offset < mddev->curr_resync)
7585 					rdev->recovery_offset = mddev->curr_resync;
7586 			rcu_read_unlock();
7587 		}
7588 	}
7589  skip:
7590 	set_bit(MD_CHANGE_DEVS, &mddev->flags);
7591 
7592 	if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
7593 		/* We completed so min/max setting can be forgotten if used. */
7594 		if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
7595 			mddev->resync_min = 0;
7596 		mddev->resync_max = MaxSector;
7597 	} else if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
7598 		mddev->resync_min = mddev->curr_resync_completed;
7599 	mddev->curr_resync = 0;
7600 	wake_up(&resync_wait);
7601 	set_bit(MD_RECOVERY_DONE, &mddev->recovery);
7602 	md_wakeup_thread(mddev->thread);
7603 	return;
7604 
7605  interrupted:
7606 	/*
7607 	 * got a signal, exit.
7608 	 */
7609 	printk(KERN_INFO
7610 	       "md: md_do_sync() got signal ... exiting\n");
7611 	set_bit(MD_RECOVERY_INTR, &mddev->recovery);
7612 	goto out;
7613 
7614 }
7615 EXPORT_SYMBOL_GPL(md_do_sync);
7616 
7617 static int remove_and_add_spares(struct mddev *mddev)
7618 {
7619 	struct md_rdev *rdev;
7620 	int spares = 0;
7621 	int removed = 0;
7622 
7623 	mddev->curr_resync_completed = 0;
7624 
7625 	rdev_for_each(rdev, mddev)
7626 		if (rdev->raid_disk >= 0 &&
7627 		    !test_bit(Blocked, &rdev->flags) &&
7628 		    (test_bit(Faulty, &rdev->flags) ||
7629 		     ! test_bit(In_sync, &rdev->flags)) &&
7630 		    atomic_read(&rdev->nr_pending)==0) {
7631 			if (mddev->pers->hot_remove_disk(
7632 				    mddev, rdev) == 0) {
7633 				sysfs_unlink_rdev(mddev, rdev);
7634 				rdev->raid_disk = -1;
7635 				removed++;
7636 			}
7637 		}
7638 	if (removed)
7639 		sysfs_notify(&mddev->kobj, NULL,
7640 			     "degraded");
7641 
7642 
7643 	rdev_for_each(rdev, mddev) {
7644 		if (rdev->raid_disk >= 0 &&
7645 		    !test_bit(In_sync, &rdev->flags) &&
7646 		    !test_bit(Faulty, &rdev->flags))
7647 			spares++;
7648 		if (rdev->raid_disk < 0
7649 		    && !test_bit(Faulty, &rdev->flags)) {
7650 			rdev->recovery_offset = 0;
7651 			if (mddev->pers->
7652 			    hot_add_disk(mddev, rdev) == 0) {
7653 				if (sysfs_link_rdev(mddev, rdev))
7654 					/* failure here is OK */;
7655 				spares++;
7656 				md_new_event(mddev);
7657 				set_bit(MD_CHANGE_DEVS, &mddev->flags);
7658 			}
7659 		}
7660 	}
7661 	return spares;
7662 }
7663 
7664 static void reap_sync_thread(struct mddev *mddev)
7665 {
7666 	struct md_rdev *rdev;
7667 
7668 	/* resync has finished, collect result */
7669 	md_unregister_thread(&mddev->sync_thread);
7670 	if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery) &&
7671 	    !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
7672 		/* success...*/
7673 		/* activate any spares */
7674 		if (mddev->pers->spare_active(mddev))
7675 			sysfs_notify(&mddev->kobj, NULL,
7676 				     "degraded");
7677 	}
7678 	if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
7679 	    mddev->pers->finish_reshape)
7680 		mddev->pers->finish_reshape(mddev);
7681 
7682 	/* If array is no-longer degraded, then any saved_raid_disk
7683 	 * information must be scrapped.  Also if any device is now
7684 	 * In_sync we must scrape the saved_raid_disk for that device
7685 	 * do the superblock for an incrementally recovered device
7686 	 * written out.
7687 	 */
7688 	rdev_for_each(rdev, mddev)
7689 		if (!mddev->degraded ||
7690 		    test_bit(In_sync, &rdev->flags))
7691 			rdev->saved_raid_disk = -1;
7692 
7693 	md_update_sb(mddev, 1);
7694 	clear_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
7695 	clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
7696 	clear_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
7697 	clear_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
7698 	clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
7699 	/* flag recovery needed just to double check */
7700 	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
7701 	sysfs_notify_dirent_safe(mddev->sysfs_action);
7702 	md_new_event(mddev);
7703 	if (mddev->event_work.func)
7704 		queue_work(md_misc_wq, &mddev->event_work);
7705 }
7706 
7707 /*
7708  * This routine is regularly called by all per-raid-array threads to
7709  * deal with generic issues like resync and super-block update.
7710  * Raid personalities that don't have a thread (linear/raid0) do not
7711  * need this as they never do any recovery or update the superblock.
7712  *
7713  * It does not do any resync itself, but rather "forks" off other threads
7714  * to do that as needed.
7715  * When it is determined that resync is needed, we set MD_RECOVERY_RUNNING in
7716  * "->recovery" and create a thread at ->sync_thread.
7717  * When the thread finishes it sets MD_RECOVERY_DONE
7718  * and wakeups up this thread which will reap the thread and finish up.
7719  * This thread also removes any faulty devices (with nr_pending == 0).
7720  *
7721  * The overall approach is:
7722  *  1/ if the superblock needs updating, update it.
7723  *  2/ If a recovery thread is running, don't do anything else.
7724  *  3/ If recovery has finished, clean up, possibly marking spares active.
7725  *  4/ If there are any faulty devices, remove them.
7726  *  5/ If array is degraded, try to add spares devices
7727  *  6/ If array has spares or is not in-sync, start a resync thread.
7728  */
7729 void md_check_recovery(struct mddev *mddev)
7730 {
7731 	if (mddev->suspended)
7732 		return;
7733 
7734 	if (mddev->bitmap)
7735 		bitmap_daemon_work(mddev);
7736 
7737 	if (signal_pending(current)) {
7738 		if (mddev->pers->sync_request && !mddev->external) {
7739 			printk(KERN_INFO "md: %s in immediate safe mode\n",
7740 			       mdname(mddev));
7741 			mddev->safemode = 2;
7742 		}
7743 		flush_signals(current);
7744 	}
7745 
7746 	if (mddev->ro && !test_bit(MD_RECOVERY_NEEDED, &mddev->recovery))
7747 		return;
7748 	if ( ! (
7749 		(mddev->flags & ~ (1<<MD_CHANGE_PENDING)) ||
7750 		test_bit(MD_RECOVERY_NEEDED, &mddev->recovery) ||
7751 		test_bit(MD_RECOVERY_DONE, &mddev->recovery) ||
7752 		(mddev->external == 0 && mddev->safemode == 1) ||
7753 		(mddev->safemode == 2 && ! atomic_read(&mddev->writes_pending)
7754 		 && !mddev->in_sync && mddev->recovery_cp == MaxSector)
7755 		))
7756 		return;
7757 
7758 	if (mddev_trylock(mddev)) {
7759 		int spares = 0;
7760 
7761 		if (mddev->ro) {
7762 			/* Only thing we do on a ro array is remove
7763 			 * failed devices.
7764 			 */
7765 			struct md_rdev *rdev;
7766 			rdev_for_each(rdev, mddev)
7767 				if (rdev->raid_disk >= 0 &&
7768 				    !test_bit(Blocked, &rdev->flags) &&
7769 				    test_bit(Faulty, &rdev->flags) &&
7770 				    atomic_read(&rdev->nr_pending)==0) {
7771 					if (mddev->pers->hot_remove_disk(
7772 						    mddev, rdev) == 0) {
7773 						sysfs_unlink_rdev(mddev, rdev);
7774 						rdev->raid_disk = -1;
7775 					}
7776 				}
7777 			clear_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
7778 			goto unlock;
7779 		}
7780 
7781 		if (!mddev->external) {
7782 			int did_change = 0;
7783 			spin_lock_irq(&mddev->write_lock);
7784 			if (mddev->safemode &&
7785 			    !atomic_read(&mddev->writes_pending) &&
7786 			    !mddev->in_sync &&
7787 			    mddev->recovery_cp == MaxSector) {
7788 				mddev->in_sync = 1;
7789 				did_change = 1;
7790 				set_bit(MD_CHANGE_CLEAN, &mddev->flags);
7791 			}
7792 			if (mddev->safemode == 1)
7793 				mddev->safemode = 0;
7794 			spin_unlock_irq(&mddev->write_lock);
7795 			if (did_change)
7796 				sysfs_notify_dirent_safe(mddev->sysfs_state);
7797 		}
7798 
7799 		if (mddev->flags)
7800 			md_update_sb(mddev, 0);
7801 
7802 		if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) &&
7803 		    !test_bit(MD_RECOVERY_DONE, &mddev->recovery)) {
7804 			/* resync/recovery still happening */
7805 			clear_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
7806 			goto unlock;
7807 		}
7808 		if (mddev->sync_thread) {
7809 			reap_sync_thread(mddev);
7810 			goto unlock;
7811 		}
7812 		/* Set RUNNING before clearing NEEDED to avoid
7813 		 * any transients in the value of "sync_action".
7814 		 */
7815 		set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
7816 		/* Clear some bits that don't mean anything, but
7817 		 * might be left set
7818 		 */
7819 		clear_bit(MD_RECOVERY_INTR, &mddev->recovery);
7820 		clear_bit(MD_RECOVERY_DONE, &mddev->recovery);
7821 
7822 		if (!test_and_clear_bit(MD_RECOVERY_NEEDED, &mddev->recovery) ||
7823 		    test_bit(MD_RECOVERY_FROZEN, &mddev->recovery))
7824 			goto unlock;
7825 		/* no recovery is running.
7826 		 * remove any failed drives, then
7827 		 * add spares if possible.
7828 		 * Spare are also removed and re-added, to allow
7829 		 * the personality to fail the re-add.
7830 		 */
7831 
7832 		if (mddev->reshape_position != MaxSector) {
7833 			if (mddev->pers->check_reshape == NULL ||
7834 			    mddev->pers->check_reshape(mddev) != 0)
7835 				/* Cannot proceed */
7836 				goto unlock;
7837 			set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
7838 			clear_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
7839 		} else if ((spares = remove_and_add_spares(mddev))) {
7840 			clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
7841 			clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
7842 			clear_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
7843 			set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
7844 		} else if (mddev->recovery_cp < MaxSector) {
7845 			set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
7846 			clear_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
7847 		} else if (!test_bit(MD_RECOVERY_SYNC, &mddev->recovery))
7848 			/* nothing to be done ... */
7849 			goto unlock;
7850 
7851 		if (mddev->pers->sync_request) {
7852 			if (spares) {
7853 				/* We are adding a device or devices to an array
7854 				 * which has the bitmap stored on all devices.
7855 				 * So make sure all bitmap pages get written
7856 				 */
7857 				bitmap_write_all(mddev->bitmap);
7858 			}
7859 			mddev->sync_thread = md_register_thread(md_do_sync,
7860 								mddev,
7861 								"resync");
7862 			if (!mddev->sync_thread) {
7863 				printk(KERN_ERR "%s: could not start resync"
7864 					" thread...\n",
7865 					mdname(mddev));
7866 				/* leave the spares where they are, it shouldn't hurt */
7867 				clear_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
7868 				clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
7869 				clear_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
7870 				clear_bit(MD_RECOVERY_REQUESTED, &mddev->recovery);
7871 				clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
7872 			} else
7873 				md_wakeup_thread(mddev->sync_thread);
7874 			sysfs_notify_dirent_safe(mddev->sysfs_action);
7875 			md_new_event(mddev);
7876 		}
7877 	unlock:
7878 		if (!mddev->sync_thread) {
7879 			clear_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
7880 			if (test_and_clear_bit(MD_RECOVERY_RECOVER,
7881 					       &mddev->recovery))
7882 				if (mddev->sysfs_action)
7883 					sysfs_notify_dirent_safe(mddev->sysfs_action);
7884 		}
7885 		mddev_unlock(mddev);
7886 	}
7887 }
7888 
7889 void md_wait_for_blocked_rdev(struct md_rdev *rdev, struct mddev *mddev)
7890 {
7891 	sysfs_notify_dirent_safe(rdev->sysfs_state);
7892 	wait_event_timeout(rdev->blocked_wait,
7893 			   !test_bit(Blocked, &rdev->flags) &&
7894 			   !test_bit(BlockedBadBlocks, &rdev->flags),
7895 			   msecs_to_jiffies(5000));
7896 	rdev_dec_pending(rdev, mddev);
7897 }
7898 EXPORT_SYMBOL(md_wait_for_blocked_rdev);
7899 
7900 void md_finish_reshape(struct mddev *mddev)
7901 {
7902 	/* called be personality module when reshape completes. */
7903 	struct md_rdev *rdev;
7904 
7905 	rdev_for_each(rdev, mddev) {
7906 		if (rdev->data_offset > rdev->new_data_offset)
7907 			rdev->sectors += rdev->data_offset - rdev->new_data_offset;
7908 		else
7909 			rdev->sectors -= rdev->new_data_offset - rdev->data_offset;
7910 		rdev->data_offset = rdev->new_data_offset;
7911 	}
7912 }
7913 EXPORT_SYMBOL(md_finish_reshape);
7914 
7915 /* Bad block management.
7916  * We can record which blocks on each device are 'bad' and so just
7917  * fail those blocks, or that stripe, rather than the whole device.
7918  * Entries in the bad-block table are 64bits wide.  This comprises:
7919  * Length of bad-range, in sectors: 0-511 for lengths 1-512
7920  * Start of bad-range, sector offset, 54 bits (allows 8 exbibytes)
7921  *  A 'shift' can be set so that larger blocks are tracked and
7922  *  consequently larger devices can be covered.
7923  * 'Acknowledged' flag - 1 bit. - the most significant bit.
7924  *
7925  * Locking of the bad-block table uses a seqlock so md_is_badblock
7926  * might need to retry if it is very unlucky.
7927  * We will sometimes want to check for bad blocks in a bi_end_io function,
7928  * so we use the write_seqlock_irq variant.
7929  *
7930  * When looking for a bad block we specify a range and want to
7931  * know if any block in the range is bad.  So we binary-search
7932  * to the last range that starts at-or-before the given endpoint,
7933  * (or "before the sector after the target range")
7934  * then see if it ends after the given start.
7935  * We return
7936  *  0 if there are no known bad blocks in the range
7937  *  1 if there are known bad block which are all acknowledged
7938  * -1 if there are bad blocks which have not yet been acknowledged in metadata.
7939  * plus the start/length of the first bad section we overlap.
7940  */
7941 int md_is_badblock(struct badblocks *bb, sector_t s, int sectors,
7942 		   sector_t *first_bad, int *bad_sectors)
7943 {
7944 	int hi;
7945 	int lo = 0;
7946 	u64 *p = bb->page;
7947 	int rv = 0;
7948 	sector_t target = s + sectors;
7949 	unsigned seq;
7950 
7951 	if (bb->shift > 0) {
7952 		/* round the start down, and the end up */
7953 		s >>= bb->shift;
7954 		target += (1<<bb->shift) - 1;
7955 		target >>= bb->shift;
7956 		sectors = target - s;
7957 	}
7958 	/* 'target' is now the first block after the bad range */
7959 
7960 retry:
7961 	seq = read_seqbegin(&bb->lock);
7962 
7963 	hi = bb->count;
7964 
7965 	/* Binary search between lo and hi for 'target'
7966 	 * i.e. for the last range that starts before 'target'
7967 	 */
7968 	/* INVARIANT: ranges before 'lo' and at-or-after 'hi'
7969 	 * are known not to be the last range before target.
7970 	 * VARIANT: hi-lo is the number of possible
7971 	 * ranges, and decreases until it reaches 1
7972 	 */
7973 	while (hi - lo > 1) {
7974 		int mid = (lo + hi) / 2;
7975 		sector_t a = BB_OFFSET(p[mid]);
7976 		if (a < target)
7977 			/* This could still be the one, earlier ranges
7978 			 * could not. */
7979 			lo = mid;
7980 		else
7981 			/* This and later ranges are definitely out. */
7982 			hi = mid;
7983 	}
7984 	/* 'lo' might be the last that started before target, but 'hi' isn't */
7985 	if (hi > lo) {
7986 		/* need to check all range that end after 's' to see if
7987 		 * any are unacknowledged.
7988 		 */
7989 		while (lo >= 0 &&
7990 		       BB_OFFSET(p[lo]) + BB_LEN(p[lo]) > s) {
7991 			if (BB_OFFSET(p[lo]) < target) {
7992 				/* starts before the end, and finishes after
7993 				 * the start, so they must overlap
7994 				 */
7995 				if (rv != -1 && BB_ACK(p[lo]))
7996 					rv = 1;
7997 				else
7998 					rv = -1;
7999 				*first_bad = BB_OFFSET(p[lo]);
8000 				*bad_sectors = BB_LEN(p[lo]);
8001 			}
8002 			lo--;
8003 		}
8004 	}
8005 
8006 	if (read_seqretry(&bb->lock, seq))
8007 		goto retry;
8008 
8009 	return rv;
8010 }
8011 EXPORT_SYMBOL_GPL(md_is_badblock);
8012 
8013 /*
8014  * Add a range of bad blocks to the table.
8015  * This might extend the table, or might contract it
8016  * if two adjacent ranges can be merged.
8017  * We binary-search to find the 'insertion' point, then
8018  * decide how best to handle it.
8019  */
8020 static int md_set_badblocks(struct badblocks *bb, sector_t s, int sectors,
8021 			    int acknowledged)
8022 {
8023 	u64 *p;
8024 	int lo, hi;
8025 	int rv = 1;
8026 
8027 	if (bb->shift < 0)
8028 		/* badblocks are disabled */
8029 		return 0;
8030 
8031 	if (bb->shift) {
8032 		/* round the start down, and the end up */
8033 		sector_t next = s + sectors;
8034 		s >>= bb->shift;
8035 		next += (1<<bb->shift) - 1;
8036 		next >>= bb->shift;
8037 		sectors = next - s;
8038 	}
8039 
8040 	write_seqlock_irq(&bb->lock);
8041 
8042 	p = bb->page;
8043 	lo = 0;
8044 	hi = bb->count;
8045 	/* Find the last range that starts at-or-before 's' */
8046 	while (hi - lo > 1) {
8047 		int mid = (lo + hi) / 2;
8048 		sector_t a = BB_OFFSET(p[mid]);
8049 		if (a <= s)
8050 			lo = mid;
8051 		else
8052 			hi = mid;
8053 	}
8054 	if (hi > lo && BB_OFFSET(p[lo]) > s)
8055 		hi = lo;
8056 
8057 	if (hi > lo) {
8058 		/* we found a range that might merge with the start
8059 		 * of our new range
8060 		 */
8061 		sector_t a = BB_OFFSET(p[lo]);
8062 		sector_t e = a + BB_LEN(p[lo]);
8063 		int ack = BB_ACK(p[lo]);
8064 		if (e >= s) {
8065 			/* Yes, we can merge with a previous range */
8066 			if (s == a && s + sectors >= e)
8067 				/* new range covers old */
8068 				ack = acknowledged;
8069 			else
8070 				ack = ack && acknowledged;
8071 
8072 			if (e < s + sectors)
8073 				e = s + sectors;
8074 			if (e - a <= BB_MAX_LEN) {
8075 				p[lo] = BB_MAKE(a, e-a, ack);
8076 				s = e;
8077 			} else {
8078 				/* does not all fit in one range,
8079 				 * make p[lo] maximal
8080 				 */
8081 				if (BB_LEN(p[lo]) != BB_MAX_LEN)
8082 					p[lo] = BB_MAKE(a, BB_MAX_LEN, ack);
8083 				s = a + BB_MAX_LEN;
8084 			}
8085 			sectors = e - s;
8086 		}
8087 	}
8088 	if (sectors && hi < bb->count) {
8089 		/* 'hi' points to the first range that starts after 's'.
8090 		 * Maybe we can merge with the start of that range */
8091 		sector_t a = BB_OFFSET(p[hi]);
8092 		sector_t e = a + BB_LEN(p[hi]);
8093 		int ack = BB_ACK(p[hi]);
8094 		if (a <= s + sectors) {
8095 			/* merging is possible */
8096 			if (e <= s + sectors) {
8097 				/* full overlap */
8098 				e = s + sectors;
8099 				ack = acknowledged;
8100 			} else
8101 				ack = ack && acknowledged;
8102 
8103 			a = s;
8104 			if (e - a <= BB_MAX_LEN) {
8105 				p[hi] = BB_MAKE(a, e-a, ack);
8106 				s = e;
8107 			} else {
8108 				p[hi] = BB_MAKE(a, BB_MAX_LEN, ack);
8109 				s = a + BB_MAX_LEN;
8110 			}
8111 			sectors = e - s;
8112 			lo = hi;
8113 			hi++;
8114 		}
8115 	}
8116 	if (sectors == 0 && hi < bb->count) {
8117 		/* we might be able to combine lo and hi */
8118 		/* Note: 's' is at the end of 'lo' */
8119 		sector_t a = BB_OFFSET(p[hi]);
8120 		int lolen = BB_LEN(p[lo]);
8121 		int hilen = BB_LEN(p[hi]);
8122 		int newlen = lolen + hilen - (s - a);
8123 		if (s >= a && newlen < BB_MAX_LEN) {
8124 			/* yes, we can combine them */
8125 			int ack = BB_ACK(p[lo]) && BB_ACK(p[hi]);
8126 			p[lo] = BB_MAKE(BB_OFFSET(p[lo]), newlen, ack);
8127 			memmove(p + hi, p + hi + 1,
8128 				(bb->count - hi - 1) * 8);
8129 			bb->count--;
8130 		}
8131 	}
8132 	while (sectors) {
8133 		/* didn't merge (it all).
8134 		 * Need to add a range just before 'hi' */
8135 		if (bb->count >= MD_MAX_BADBLOCKS) {
8136 			/* No room for more */
8137 			rv = 0;
8138 			break;
8139 		} else {
8140 			int this_sectors = sectors;
8141 			memmove(p + hi + 1, p + hi,
8142 				(bb->count - hi) * 8);
8143 			bb->count++;
8144 
8145 			if (this_sectors > BB_MAX_LEN)
8146 				this_sectors = BB_MAX_LEN;
8147 			p[hi] = BB_MAKE(s, this_sectors, acknowledged);
8148 			sectors -= this_sectors;
8149 			s += this_sectors;
8150 		}
8151 	}
8152 
8153 	bb->changed = 1;
8154 	if (!acknowledged)
8155 		bb->unacked_exist = 1;
8156 	write_sequnlock_irq(&bb->lock);
8157 
8158 	return rv;
8159 }
8160 
8161 int rdev_set_badblocks(struct md_rdev *rdev, sector_t s, int sectors,
8162 		       int is_new)
8163 {
8164 	int rv;
8165 	if (is_new)
8166 		s += rdev->new_data_offset;
8167 	else
8168 		s += rdev->data_offset;
8169 	rv = md_set_badblocks(&rdev->badblocks,
8170 			      s, sectors, 0);
8171 	if (rv) {
8172 		/* Make sure they get written out promptly */
8173 		sysfs_notify_dirent_safe(rdev->sysfs_state);
8174 		set_bit(MD_CHANGE_CLEAN, &rdev->mddev->flags);
8175 		md_wakeup_thread(rdev->mddev->thread);
8176 	}
8177 	return rv;
8178 }
8179 EXPORT_SYMBOL_GPL(rdev_set_badblocks);
8180 
8181 /*
8182  * Remove a range of bad blocks from the table.
8183  * This may involve extending the table if we spilt a region,
8184  * but it must not fail.  So if the table becomes full, we just
8185  * drop the remove request.
8186  */
8187 static int md_clear_badblocks(struct badblocks *bb, sector_t s, int sectors)
8188 {
8189 	u64 *p;
8190 	int lo, hi;
8191 	sector_t target = s + sectors;
8192 	int rv = 0;
8193 
8194 	if (bb->shift > 0) {
8195 		/* When clearing we round the start up and the end down.
8196 		 * This should not matter as the shift should align with
8197 		 * the block size and no rounding should ever be needed.
8198 		 * However it is better the think a block is bad when it
8199 		 * isn't than to think a block is not bad when it is.
8200 		 */
8201 		s += (1<<bb->shift) - 1;
8202 		s >>= bb->shift;
8203 		target >>= bb->shift;
8204 		sectors = target - s;
8205 	}
8206 
8207 	write_seqlock_irq(&bb->lock);
8208 
8209 	p = bb->page;
8210 	lo = 0;
8211 	hi = bb->count;
8212 	/* Find the last range that starts before 'target' */
8213 	while (hi - lo > 1) {
8214 		int mid = (lo + hi) / 2;
8215 		sector_t a = BB_OFFSET(p[mid]);
8216 		if (a < target)
8217 			lo = mid;
8218 		else
8219 			hi = mid;
8220 	}
8221 	if (hi > lo) {
8222 		/* p[lo] is the last range that could overlap the
8223 		 * current range.  Earlier ranges could also overlap,
8224 		 * but only this one can overlap the end of the range.
8225 		 */
8226 		if (BB_OFFSET(p[lo]) + BB_LEN(p[lo]) > target) {
8227 			/* Partial overlap, leave the tail of this range */
8228 			int ack = BB_ACK(p[lo]);
8229 			sector_t a = BB_OFFSET(p[lo]);
8230 			sector_t end = a + BB_LEN(p[lo]);
8231 
8232 			if (a < s) {
8233 				/* we need to split this range */
8234 				if (bb->count >= MD_MAX_BADBLOCKS) {
8235 					rv = 0;
8236 					goto out;
8237 				}
8238 				memmove(p+lo+1, p+lo, (bb->count - lo) * 8);
8239 				bb->count++;
8240 				p[lo] = BB_MAKE(a, s-a, ack);
8241 				lo++;
8242 			}
8243 			p[lo] = BB_MAKE(target, end - target, ack);
8244 			/* there is no longer an overlap */
8245 			hi = lo;
8246 			lo--;
8247 		}
8248 		while (lo >= 0 &&
8249 		       BB_OFFSET(p[lo]) + BB_LEN(p[lo]) > s) {
8250 			/* This range does overlap */
8251 			if (BB_OFFSET(p[lo]) < s) {
8252 				/* Keep the early parts of this range. */
8253 				int ack = BB_ACK(p[lo]);
8254 				sector_t start = BB_OFFSET(p[lo]);
8255 				p[lo] = BB_MAKE(start, s - start, ack);
8256 				/* now low doesn't overlap, so.. */
8257 				break;
8258 			}
8259 			lo--;
8260 		}
8261 		/* 'lo' is strictly before, 'hi' is strictly after,
8262 		 * anything between needs to be discarded
8263 		 */
8264 		if (hi - lo > 1) {
8265 			memmove(p+lo+1, p+hi, (bb->count - hi) * 8);
8266 			bb->count -= (hi - lo - 1);
8267 		}
8268 	}
8269 
8270 	bb->changed = 1;
8271 out:
8272 	write_sequnlock_irq(&bb->lock);
8273 	return rv;
8274 }
8275 
8276 int rdev_clear_badblocks(struct md_rdev *rdev, sector_t s, int sectors,
8277 			 int is_new)
8278 {
8279 	if (is_new)
8280 		s += rdev->new_data_offset;
8281 	else
8282 		s += rdev->data_offset;
8283 	return md_clear_badblocks(&rdev->badblocks,
8284 				  s, sectors);
8285 }
8286 EXPORT_SYMBOL_GPL(rdev_clear_badblocks);
8287 
8288 /*
8289  * Acknowledge all bad blocks in a list.
8290  * This only succeeds if ->changed is clear.  It is used by
8291  * in-kernel metadata updates
8292  */
8293 void md_ack_all_badblocks(struct badblocks *bb)
8294 {
8295 	if (bb->page == NULL || bb->changed)
8296 		/* no point even trying */
8297 		return;
8298 	write_seqlock_irq(&bb->lock);
8299 
8300 	if (bb->changed == 0 && bb->unacked_exist) {
8301 		u64 *p = bb->page;
8302 		int i;
8303 		for (i = 0; i < bb->count ; i++) {
8304 			if (!BB_ACK(p[i])) {
8305 				sector_t start = BB_OFFSET(p[i]);
8306 				int len = BB_LEN(p[i]);
8307 				p[i] = BB_MAKE(start, len, 1);
8308 			}
8309 		}
8310 		bb->unacked_exist = 0;
8311 	}
8312 	write_sequnlock_irq(&bb->lock);
8313 }
8314 EXPORT_SYMBOL_GPL(md_ack_all_badblocks);
8315 
8316 /* sysfs access to bad-blocks list.
8317  * We present two files.
8318  * 'bad-blocks' lists sector numbers and lengths of ranges that
8319  *    are recorded as bad.  The list is truncated to fit within
8320  *    the one-page limit of sysfs.
8321  *    Writing "sector length" to this file adds an acknowledged
8322  *    bad block list.
8323  * 'unacknowledged-bad-blocks' lists bad blocks that have not yet
8324  *    been acknowledged.  Writing to this file adds bad blocks
8325  *    without acknowledging them.  This is largely for testing.
8326  */
8327 
8328 static ssize_t
8329 badblocks_show(struct badblocks *bb, char *page, int unack)
8330 {
8331 	size_t len;
8332 	int i;
8333 	u64 *p = bb->page;
8334 	unsigned seq;
8335 
8336 	if (bb->shift < 0)
8337 		return 0;
8338 
8339 retry:
8340 	seq = read_seqbegin(&bb->lock);
8341 
8342 	len = 0;
8343 	i = 0;
8344 
8345 	while (len < PAGE_SIZE && i < bb->count) {
8346 		sector_t s = BB_OFFSET(p[i]);
8347 		unsigned int length = BB_LEN(p[i]);
8348 		int ack = BB_ACK(p[i]);
8349 		i++;
8350 
8351 		if (unack && ack)
8352 			continue;
8353 
8354 		len += snprintf(page+len, PAGE_SIZE-len, "%llu %u\n",
8355 				(unsigned long long)s << bb->shift,
8356 				length << bb->shift);
8357 	}
8358 	if (unack && len == 0)
8359 		bb->unacked_exist = 0;
8360 
8361 	if (read_seqretry(&bb->lock, seq))
8362 		goto retry;
8363 
8364 	return len;
8365 }
8366 
8367 #define DO_DEBUG 1
8368 
8369 static ssize_t
8370 badblocks_store(struct badblocks *bb, const char *page, size_t len, int unack)
8371 {
8372 	unsigned long long sector;
8373 	int length;
8374 	char newline;
8375 #ifdef DO_DEBUG
8376 	/* Allow clearing via sysfs *only* for testing/debugging.
8377 	 * Normally only a successful write may clear a badblock
8378 	 */
8379 	int clear = 0;
8380 	if (page[0] == '-') {
8381 		clear = 1;
8382 		page++;
8383 	}
8384 #endif /* DO_DEBUG */
8385 
8386 	switch (sscanf(page, "%llu %d%c", &sector, &length, &newline)) {
8387 	case 3:
8388 		if (newline != '\n')
8389 			return -EINVAL;
8390 	case 2:
8391 		if (length <= 0)
8392 			return -EINVAL;
8393 		break;
8394 	default:
8395 		return -EINVAL;
8396 	}
8397 
8398 #ifdef DO_DEBUG
8399 	if (clear) {
8400 		md_clear_badblocks(bb, sector, length);
8401 		return len;
8402 	}
8403 #endif /* DO_DEBUG */
8404 	if (md_set_badblocks(bb, sector, length, !unack))
8405 		return len;
8406 	else
8407 		return -ENOSPC;
8408 }
8409 
8410 static int md_notify_reboot(struct notifier_block *this,
8411 			    unsigned long code, void *x)
8412 {
8413 	struct list_head *tmp;
8414 	struct mddev *mddev;
8415 	int need_delay = 0;
8416 
8417 	for_each_mddev(mddev, tmp) {
8418 		if (mddev_trylock(mddev)) {
8419 			if (mddev->pers)
8420 				__md_stop_writes(mddev);
8421 			mddev->safemode = 2;
8422 			mddev_unlock(mddev);
8423 		}
8424 		need_delay = 1;
8425 	}
8426 	/*
8427 	 * certain more exotic SCSI devices are known to be
8428 	 * volatile wrt too early system reboots. While the
8429 	 * right place to handle this issue is the given
8430 	 * driver, we do want to have a safe RAID driver ...
8431 	 */
8432 	if (need_delay)
8433 		mdelay(1000*1);
8434 
8435 	return NOTIFY_DONE;
8436 }
8437 
8438 static struct notifier_block md_notifier = {
8439 	.notifier_call	= md_notify_reboot,
8440 	.next		= NULL,
8441 	.priority	= INT_MAX, /* before any real devices */
8442 };
8443 
8444 static void md_geninit(void)
8445 {
8446 	pr_debug("md: sizeof(mdp_super_t) = %d\n", (int)sizeof(mdp_super_t));
8447 
8448 	proc_create("mdstat", S_IRUGO, NULL, &md_seq_fops);
8449 }
8450 
8451 static int __init md_init(void)
8452 {
8453 	int ret = -ENOMEM;
8454 
8455 	md_wq = alloc_workqueue("md", WQ_MEM_RECLAIM, 0);
8456 	if (!md_wq)
8457 		goto err_wq;
8458 
8459 	md_misc_wq = alloc_workqueue("md_misc", 0, 0);
8460 	if (!md_misc_wq)
8461 		goto err_misc_wq;
8462 
8463 	if ((ret = register_blkdev(MD_MAJOR, "md")) < 0)
8464 		goto err_md;
8465 
8466 	if ((ret = register_blkdev(0, "mdp")) < 0)
8467 		goto err_mdp;
8468 	mdp_major = ret;
8469 
8470 	blk_register_region(MKDEV(MD_MAJOR, 0), 1UL<<MINORBITS, THIS_MODULE,
8471 			    md_probe, NULL, NULL);
8472 	blk_register_region(MKDEV(mdp_major, 0), 1UL<<MINORBITS, THIS_MODULE,
8473 			    md_probe, NULL, NULL);
8474 
8475 	register_reboot_notifier(&md_notifier);
8476 	raid_table_header = register_sysctl_table(raid_root_table);
8477 
8478 	md_geninit();
8479 	return 0;
8480 
8481 err_mdp:
8482 	unregister_blkdev(MD_MAJOR, "md");
8483 err_md:
8484 	destroy_workqueue(md_misc_wq);
8485 err_misc_wq:
8486 	destroy_workqueue(md_wq);
8487 err_wq:
8488 	return ret;
8489 }
8490 
8491 #ifndef MODULE
8492 
8493 /*
8494  * Searches all registered partitions for autorun RAID arrays
8495  * at boot time.
8496  */
8497 
8498 static LIST_HEAD(all_detected_devices);
8499 struct detected_devices_node {
8500 	struct list_head list;
8501 	dev_t dev;
8502 };
8503 
8504 void md_autodetect_dev(dev_t dev)
8505 {
8506 	struct detected_devices_node *node_detected_dev;
8507 
8508 	node_detected_dev = kzalloc(sizeof(*node_detected_dev), GFP_KERNEL);
8509 	if (node_detected_dev) {
8510 		node_detected_dev->dev = dev;
8511 		list_add_tail(&node_detected_dev->list, &all_detected_devices);
8512 	} else {
8513 		printk(KERN_CRIT "md: md_autodetect_dev: kzalloc failed"
8514 			", skipping dev(%d,%d)\n", MAJOR(dev), MINOR(dev));
8515 	}
8516 }
8517 
8518 
8519 static void autostart_arrays(int part)
8520 {
8521 	struct md_rdev *rdev;
8522 	struct detected_devices_node *node_detected_dev;
8523 	dev_t dev;
8524 	int i_scanned, i_passed;
8525 
8526 	i_scanned = 0;
8527 	i_passed = 0;
8528 
8529 	printk(KERN_INFO "md: Autodetecting RAID arrays.\n");
8530 
8531 	while (!list_empty(&all_detected_devices) && i_scanned < INT_MAX) {
8532 		i_scanned++;
8533 		node_detected_dev = list_entry(all_detected_devices.next,
8534 					struct detected_devices_node, list);
8535 		list_del(&node_detected_dev->list);
8536 		dev = node_detected_dev->dev;
8537 		kfree(node_detected_dev);
8538 		rdev = md_import_device(dev,0, 90);
8539 		if (IS_ERR(rdev))
8540 			continue;
8541 
8542 		if (test_bit(Faulty, &rdev->flags)) {
8543 			MD_BUG();
8544 			continue;
8545 		}
8546 		set_bit(AutoDetected, &rdev->flags);
8547 		list_add(&rdev->same_set, &pending_raid_disks);
8548 		i_passed++;
8549 	}
8550 
8551 	printk(KERN_INFO "md: Scanned %d and added %d devices.\n",
8552 						i_scanned, i_passed);
8553 
8554 	autorun_devices(part);
8555 }
8556 
8557 #endif /* !MODULE */
8558 
8559 static __exit void md_exit(void)
8560 {
8561 	struct mddev *mddev;
8562 	struct list_head *tmp;
8563 
8564 	blk_unregister_region(MKDEV(MD_MAJOR,0), 1U << MINORBITS);
8565 	blk_unregister_region(MKDEV(mdp_major,0), 1U << MINORBITS);
8566 
8567 	unregister_blkdev(MD_MAJOR,"md");
8568 	unregister_blkdev(mdp_major, "mdp");
8569 	unregister_reboot_notifier(&md_notifier);
8570 	unregister_sysctl_table(raid_table_header);
8571 	remove_proc_entry("mdstat", NULL);
8572 	for_each_mddev(mddev, tmp) {
8573 		export_array(mddev);
8574 		mddev->hold_active = 0;
8575 	}
8576 	destroy_workqueue(md_misc_wq);
8577 	destroy_workqueue(md_wq);
8578 }
8579 
8580 subsys_initcall(md_init);
8581 module_exit(md_exit)
8582 
8583 static int get_ro(char *buffer, struct kernel_param *kp)
8584 {
8585 	return sprintf(buffer, "%d", start_readonly);
8586 }
8587 static int set_ro(const char *val, struct kernel_param *kp)
8588 {
8589 	char *e;
8590 	int num = simple_strtoul(val, &e, 10);
8591 	if (*val && (*e == '\0' || *e == '\n')) {
8592 		start_readonly = num;
8593 		return 0;
8594 	}
8595 	return -EINVAL;
8596 }
8597 
8598 module_param_call(start_ro, set_ro, get_ro, NULL, S_IRUSR|S_IWUSR);
8599 module_param(start_dirty_degraded, int, S_IRUGO|S_IWUSR);
8600 
8601 module_param_call(new_array, add_named_array, NULL, NULL, S_IWUSR);
8602 
8603 EXPORT_SYMBOL(register_md_personality);
8604 EXPORT_SYMBOL(unregister_md_personality);
8605 EXPORT_SYMBOL(md_error);
8606 EXPORT_SYMBOL(md_done_sync);
8607 EXPORT_SYMBOL(md_write_start);
8608 EXPORT_SYMBOL(md_write_end);
8609 EXPORT_SYMBOL(md_register_thread);
8610 EXPORT_SYMBOL(md_unregister_thread);
8611 EXPORT_SYMBOL(md_wakeup_thread);
8612 EXPORT_SYMBOL(md_check_recovery);
8613 MODULE_LICENSE("GPL");
8614 MODULE_DESCRIPTION("MD RAID framework");
8615 MODULE_ALIAS("md");
8616 MODULE_ALIAS_BLOCKDEV_MAJOR(MD_MAJOR);
8617