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Root/drivers/md/raid10.c

1	/*
2	* raid10.c : Multiple Devices driver for Linux
3	*
4	* Copyright (C) 2000-2004 Neil Brown
5	*
6	* RAID-10 support for md.
7	*
8	* Base on code in raid1.c. See raid1.c for further copyright information.
9	*
10	*
11	* This program is free software; you can redistribute it and/or modify
12	* it under the terms of the GNU General Public License as published by
13	* the Free Software Foundation; either version 2, or (at your option)
14	* any later version.
15	*
16	* You should have received a copy of the GNU General Public License
17	* (for example /usr/src/linux/COPYING); if not, write to the Free
18	* Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
19	*/
20
21	#include <linux/slab.h>
22	#include <linux/delay.h>
23	#include <linux/blkdev.h>
24	#include <linux/module.h>
25	#include <linux/seq_file.h>
26	#include <linux/ratelimit.h>
27	#include <linux/kthread.h>
28	#include "md.h"
29	#include "raid10.h"
30	#include "raid0.h"
31	#include "bitmap.h"
32
33	/*
34	* RAID10 provides a combination of RAID0 and RAID1 functionality.
35	* The layout of data is defined by
36	* chunk_size
37	* raid_disks
38	* near_copies (stored in low byte of layout)
39	* far_copies (stored in second byte of layout)
40	* far_offset (stored in bit 16 of layout )
41	*
42	* The data to be stored is divided into chunks using chunksize.
43	* Each device is divided into far_copies sections.
44	* In each section, chunks are laid out in a style similar to raid0, but
45	* near_copies copies of each chunk is stored (each on a different drive).
46	* The starting device for each section is offset near_copies from the starting
47	* device of the previous section.
48	* Thus they are (near_copies*far_copies) of each chunk, and each is on a different
49	* drive.
50	* near_copies and far_copies must be at least one, and their product is at most
51	* raid_disks.
52	*
53	* If far_offset is true, then the far_copies are handled a bit differently.
54	* The copies are still in different stripes, but instead of be very far apart
55	* on disk, there are adjacent stripes.
56	*/
57
58	/*
59	* Number of guaranteed r10bios in case of extreme VM load:
60	*/
61	#define NR_RAID10_BIOS 256
62
63	/* when we get a read error on a read-only array, we redirect to another
64	* device without failing the first device, or trying to over-write to
65	* correct the read error. To keep track of bad blocks on a per-bio
66	* level, we store IO_BLOCKED in the appropriate 'bios' pointer
67	*/
68	#define IO_BLOCKED ((struct bio *)1)
69	/* When we successfully write to a known bad-block, we need to remove the
70	* bad-block marking which must be done from process context. So we record
71	* the success by setting devs[n].bio to IO_MADE_GOOD
72	*/
73	#define IO_MADE_GOOD ((struct bio *)2)
74
75	#define BIO_SPECIAL(bio) ((unsigned long)bio <= 2)
76
77	/* When there are this many requests queued to be written by
78	* the raid10 thread, we become 'congested' to provide back-pressure
79	* for writeback.
80	*/
81	static int max_queued_requests = 1024;
82
83	static void allow_barrier(struct r10conf *conf);
84	static void lower_barrier(struct r10conf *conf);
85	static int enough(struct r10conf *conf, int ignore);
86	static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr,
87	int *skipped);
88	static void reshape_request_write(struct mddev mddev, struct r10bio r10_bio);
89	static void end_reshape_write(struct bio *bio, int error);
90	static void end_reshape(struct r10conf *conf);
91
92	static void * r10bio_pool_alloc(gfp_t gfp_flags, void *data)
93	{
94	struct r10conf *conf = data;
95	int size = offsetof(struct r10bio, devs[conf->copies]);
96
97	/* allocate a r10bio with room for raid_disks entries in the
98	* bios array */
99	return kzalloc(size, gfp_flags);
100	}
101
102	static void r10bio_pool_free(void r10_bio, void data)
103	{
104	kfree(r10_bio);
105	}
106
107	/* Maximum size of each resync request */
108	#define RESYNC_BLOCK_SIZE (64*1024)
109	#define RESYNC_PAGES ((RESYNC_BLOCK_SIZE + PAGE_SIZE-1) / PAGE_SIZE)
110	/* amount of memory to reserve for resync requests */
111	#define RESYNC_WINDOW (1024*1024)
112	/* maximum number of concurrent requests, memory permitting */
113	#define RESYNC_DEPTH (3210241024/RESYNC_BLOCK_SIZE)
114
115	/*
116	* When performing a resync, we need to read and compare, so
117	* we need as many pages are there are copies.
118	* When performing a recovery, we need 2 bios, one for read,
119	* one for write (we recover only one drive per r10buf)
120	*
121	*/
122	static void * r10buf_pool_alloc(gfp_t gfp_flags, void *data)
123	{
124	struct r10conf *conf = data;
125	struct page *page;
126	struct r10bio *r10_bio;
127	struct bio *bio;
128	int i, j;
129	int nalloc;
130
131	r10_bio = r10bio_pool_alloc(gfp_flags, conf);
132	if (!r10_bio)
133	return NULL;
134
135	if (test_bit(MD_RECOVERY_SYNC, &conf->mddev->recovery) \|\|
136	test_bit(MD_RECOVERY_RESHAPE, &conf->mddev->recovery))
137	nalloc = conf->copies; /* resync */
138	else
139	nalloc = 2; /* recovery */
140
141	/*
142	* Allocate bios.
143	*/
144	for (j = nalloc ; j-- ; ) {
145	bio = bio_kmalloc(gfp_flags, RESYNC_PAGES);
146	if (!bio)
147	goto out_free_bio;
148	r10_bio->devs[j].bio = bio;
149	if (!conf->have_replacement)
150	continue;
151	bio = bio_kmalloc(gfp_flags, RESYNC_PAGES);
152	if (!bio)
153	goto out_free_bio;
154	r10_bio->devs[j].repl_bio = bio;
155	}
156	/*
157	* Allocate RESYNC_PAGES data pages and attach them
158	* where needed.
159	*/
160	for (j = 0 ; j < nalloc; j++) {
161	struct bio *rbio = r10_bio->devs[j].repl_bio;
162	bio = r10_bio->devs[j].bio;
163	for (i = 0; i < RESYNC_PAGES; i++) {
164	if (j > 0 && !test_bit(MD_RECOVERY_SYNC,
165	&conf->mddev->recovery)) {
166	/* we can share bv_page's during recovery
167	* and reshape */
168	struct bio *rbio = r10_bio->devs[0].bio;
169	page = rbio->bi_io_vec[i].bv_page;
170	get_page(page);
171	} else
172	page = alloc_page(gfp_flags);
173	if (unlikely(!page))
174	goto out_free_pages;
175
176	bio->bi_io_vec[i].bv_page = page;
177	if (rbio)
178	rbio->bi_io_vec[i].bv_page = page;
179	}
180	}
181
182	return r10_bio;
183
184	out_free_pages:
185	for ( ; i > 0 ; i--)
186	safe_put_page(bio->bi_io_vec[i-1].bv_page);
187	while (j--)
188	for (i = 0; i < RESYNC_PAGES ; i++)
189	safe_put_page(r10_bio->devs[j].bio->bi_io_vec[i].bv_page);
190	j = 0;
191	out_free_bio:
192	for ( ; j < nalloc; j++) {
193	if (r10_bio->devs[j].bio)
194	bio_put(r10_bio->devs[j].bio);
195	if (r10_bio->devs[j].repl_bio)
196	bio_put(r10_bio->devs[j].repl_bio);
197	}
198	r10bio_pool_free(r10_bio, conf);
199	return NULL;
200	}
201
202	static void r10buf_pool_free(void __r10_bio, void data)
203	{
204	int i;
205	struct r10conf *conf = data;
206	struct r10bio *r10bio = __r10_bio;
207	int j;
208
209	for (j=0; j < conf->copies; j++) {
210	struct bio *bio = r10bio->devs[j].bio;
211	if (bio) {
212	for (i = 0; i < RESYNC_PAGES; i++) {
213	safe_put_page(bio->bi_io_vec[i].bv_page);
214	bio->bi_io_vec[i].bv_page = NULL;
215	}
216	bio_put(bio);
217	}
218	bio = r10bio->devs[j].repl_bio;
219	if (bio)
220	bio_put(bio);
221	}
222	r10bio_pool_free(r10bio, conf);
223	}
224
225	static void put_all_bios(struct r10conf conf, struct r10bio r10_bio)
226	{
227	int i;
228
229	for (i = 0; i < conf->copies; i++) {
230	struct bio **bio = & r10_bio->devs[i].bio;
231	if (!BIO_SPECIAL(*bio))
232	bio_put(*bio);
233	*bio = NULL;
234	bio = &r10_bio->devs[i].repl_bio;
235	if (r10_bio->read_slot < 0 && !BIO_SPECIAL(*bio))
236	bio_put(*bio);
237	*bio = NULL;
238	}
239	}
240
241	static void free_r10bio(struct r10bio *r10_bio)
242	{
243	struct r10conf *conf = r10_bio->mddev->private;
244
245	put_all_bios(conf, r10_bio);
246	mempool_free(r10_bio, conf->r10bio_pool);
247	}
248
249	static void put_buf(struct r10bio *r10_bio)
250	{
251	struct r10conf *conf = r10_bio->mddev->private;
252
253	mempool_free(r10_bio, conf->r10buf_pool);
254
255	lower_barrier(conf);
256	}
257
258	static void reschedule_retry(struct r10bio *r10_bio)
259	{
260	unsigned long flags;
261	struct mddev *mddev = r10_bio->mddev;
262	struct r10conf *conf = mddev->private;
263
264	spin_lock_irqsave(&conf->device_lock, flags);
265	list_add(&r10_bio->retry_list, &conf->retry_list);
266	conf->nr_queued ++;
267	spin_unlock_irqrestore(&conf->device_lock, flags);
268
269	/* wake up frozen array... */
270	wake_up(&conf->wait_barrier);
271
272	md_wakeup_thread(mddev->thread);
273	}
274
275	/*
276	* raid_end_bio_io() is called when we have finished servicing a mirrored
277	* operation and are ready to return a success/failure code to the buffer
278	* cache layer.
279	*/
280	static void raid_end_bio_io(struct r10bio *r10_bio)
281	{
282	struct bio *bio = r10_bio->master_bio;
283	int done;
284	struct r10conf *conf = r10_bio->mddev->private;
285
286	if (bio->bi_phys_segments) {
287	unsigned long flags;
288	spin_lock_irqsave(&conf->device_lock, flags);
289	bio->bi_phys_segments--;
290	done = (bio->bi_phys_segments == 0);
291	spin_unlock_irqrestore(&conf->device_lock, flags);
292	} else
293	done = 1;
294	if (!test_bit(R10BIO_Uptodate, &r10_bio->state))
295	clear_bit(BIO_UPTODATE, &bio->bi_flags);
296	if (done) {
297	bio_endio(bio, 0);
298	/*
299	* Wake up any possible resync thread that waits for the device
300	* to go idle.
301	*/
302	allow_barrier(conf);
303	}
304	free_r10bio(r10_bio);
305	}
306
307	/*
308	* Update disk head position estimator based on IRQ completion info.
309	*/
310	static inline void update_head_pos(int slot, struct r10bio *r10_bio)
311	{
312	struct r10conf *conf = r10_bio->mddev->private;
313
314	conf->mirrors[r10_bio->devs[slot].devnum].head_position =
315	r10_bio->devs[slot].addr + (r10_bio->sectors);
316	}
317
318	/*
319	* Find the disk number which triggered given bio
320	*/
321	static int find_bio_disk(struct r10conf conf, struct r10bio r10_bio,
322	struct bio bio, int slotp, int *replp)
323	{
324	int slot;
325	int repl = 0;
326
327	for (slot = 0; slot < conf->copies; slot++) {
328	if (r10_bio->devs[slot].bio == bio)
329	break;
330	if (r10_bio->devs[slot].repl_bio == bio) {
331	repl = 1;
332	break;
333	}
334	}
335
336	BUG_ON(slot == conf->copies);
337	update_head_pos(slot, r10_bio);
338
339	if (slotp)
340	*slotp = slot;
341	if (replp)
342	*replp = repl;
343	return r10_bio->devs[slot].devnum;
344	}
345
346	static void raid10_end_read_request(struct bio *bio, int error)
347	{
348	int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
349	struct r10bio *r10_bio = bio->bi_private;
350	int slot, dev;
351	struct md_rdev *rdev;
352	struct r10conf *conf = r10_bio->mddev->private;
353
354
355	slot = r10_bio->read_slot;
356	dev = r10_bio->devs[slot].devnum;
357	rdev = r10_bio->devs[slot].rdev;
358	/*
359	* this branch is our 'one mirror IO has finished' event handler:
360	*/
361	update_head_pos(slot, r10_bio);
362
363	if (uptodate) {
364	/*
365	* Set R10BIO_Uptodate in our master bio, so that
366	* we will return a good error code to the higher
367	* levels even if IO on some other mirrored buffer fails.
368	*
369	* The 'master' represents the composite IO operation to
370	* user-side. So if something waits for IO, then it will
371	* wait for the 'master' bio.
372	*/
373	set_bit(R10BIO_Uptodate, &r10_bio->state);
374	} else {
375	/* If all other devices that store this block have
376	* failed, we want to return the error upwards rather
377	* than fail the last device. Here we redefine
378	* "uptodate" to mean "Don't want to retry"
379	*/
380	unsigned long flags;
381	spin_lock_irqsave(&conf->device_lock, flags);
382	if (!enough(conf, rdev->raid_disk))
383	uptodate = 1;
384	spin_unlock_irqrestore(&conf->device_lock, flags);
385	}
386	if (uptodate) {
387	raid_end_bio_io(r10_bio);
388	rdev_dec_pending(rdev, conf->mddev);
389	} else {
390	/*
391	* oops, read error - keep the refcount on the rdev
392	*/
393	char b[BDEVNAME_SIZE];
394	printk_ratelimited(KERN_ERR
395	"md/raid10:%s: %s: rescheduling sector %llu\n",
396	mdname(conf->mddev),
397	bdevname(rdev->bdev, b),
398	(unsigned long long)r10_bio->sector);
399	set_bit(R10BIO_ReadError, &r10_bio->state);
400	reschedule_retry(r10_bio);
401	}
402	}
403
404	static void close_write(struct r10bio *r10_bio)
405	{
406	/* clear the bitmap if all writes complete successfully */
407	bitmap_endwrite(r10_bio->mddev->bitmap, r10_bio->sector,
408	r10_bio->sectors,
409	!test_bit(R10BIO_Degraded, &r10_bio->state),
410	0);
411	md_write_end(r10_bio->mddev);
412	}
413
414	static void one_write_done(struct r10bio *r10_bio)
415	{
416	if (atomic_dec_and_test(&r10_bio->remaining)) {
417	if (test_bit(R10BIO_WriteError, &r10_bio->state))
418	reschedule_retry(r10_bio);
419	else {
420	close_write(r10_bio);
421	if (test_bit(R10BIO_MadeGood, &r10_bio->state))
422	reschedule_retry(r10_bio);
423	else
424	raid_end_bio_io(r10_bio);
425	}
426	}
427	}
428
429	static void raid10_end_write_request(struct bio *bio, int error)
430	{
431	int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
432	struct r10bio *r10_bio = bio->bi_private;
433	int dev;
434	int dec_rdev = 1;
435	struct r10conf *conf = r10_bio->mddev->private;
436	int slot, repl;
437	struct md_rdev *rdev = NULL;
438
439	dev = find_bio_disk(conf, r10_bio, bio, &slot, &repl);
440
441	if (repl)
442	rdev = conf->mirrors[dev].replacement;
443	if (!rdev) {
444	smp_rmb();
445	repl = 0;
446	rdev = conf->mirrors[dev].rdev;
447	}
448	/*
449	* this branch is our 'one mirror IO has finished' event handler:
450	*/
451	if (!uptodate) {
452	if (repl)
453	/* Never record new bad blocks to replacement,
454	* just fail it.
455	*/
456	md_error(rdev->mddev, rdev);
457	else {
458	set_bit(WriteErrorSeen, &rdev->flags);
459	if (!test_and_set_bit(WantReplacement, &rdev->flags))
460	set_bit(MD_RECOVERY_NEEDED,
461	&rdev->mddev->recovery);
462	set_bit(R10BIO_WriteError, &r10_bio->state);
463	dec_rdev = 0;
464	}
465	} else {
466	/*
467	* Set R10BIO_Uptodate in our master bio, so that
468	* we will return a good error code for to the higher
469	* levels even if IO on some other mirrored buffer fails.
470	*
471	* The 'master' represents the composite IO operation to
472	* user-side. So if something waits for IO, then it will
473	* wait for the 'master' bio.
474	*/
475	sector_t first_bad;
476	int bad_sectors;
477
478	set_bit(R10BIO_Uptodate, &r10_bio->state);
479
480	/* Maybe we can clear some bad blocks. */
481	if (is_badblock(rdev,
482	r10_bio->devs[slot].addr,
483	r10_bio->sectors,
484	&first_bad, &bad_sectors)) {
485	bio_put(bio);
486	if (repl)
487	r10_bio->devs[slot].repl_bio = IO_MADE_GOOD;
488	else
489	r10_bio->devs[slot].bio = IO_MADE_GOOD;
490	dec_rdev = 0;
491	set_bit(R10BIO_MadeGood, &r10_bio->state);
492	}
493	}
494
495	/*
496	*
497	* Let's see if all mirrored write operations have finished
498	* already.
499	*/
500	one_write_done(r10_bio);
501	if (dec_rdev)
502	rdev_dec_pending(conf->mirrors[dev].rdev, conf->mddev);
503	}
504
505	/*
506	* RAID10 layout manager
507	* As well as the chunksize and raid_disks count, there are two
508	* parameters: near_copies and far_copies.
509	* near_copies * far_copies must be <= raid_disks.
510	* Normally one of these will be 1.
511	* If both are 1, we get raid0.
512	* If near_copies == raid_disks, we get raid1.
513	*
514	* Chunks are laid out in raid0 style with near_copies copies of the
515	* first chunk, followed by near_copies copies of the next chunk and
516	* so on.
517	* If far_copies > 1, then after 1/far_copies of the array has been assigned
518	* as described above, we start again with a device offset of near_copies.
519	* So we effectively have another copy of the whole array further down all
520	* the drives, but with blocks on different drives.
521	* With this layout, and block is never stored twice on the one device.
522	*
523	* raid10_find_phys finds the sector offset of a given virtual sector
524	* on each device that it is on.
525	*
526	* raid10_find_virt does the reverse mapping, from a device and a
527	* sector offset to a virtual address
528	*/
529
530	static void __raid10_find_phys(struct geom geo, struct r10bio r10bio)
531	{
532	int n,f;
533	sector_t sector;
534	sector_t chunk;
535	sector_t stripe;
536	int dev;
537	int slot = 0;
538
539	/* now calculate first sector/dev */
540	chunk = r10bio->sector >> geo->chunk_shift;
541	sector = r10bio->sector & geo->chunk_mask;
542
543	chunk *= geo->near_copies;
544	stripe = chunk;
545	dev = sector_div(stripe, geo->raid_disks);
546	if (geo->far_offset)
547	stripe *= geo->far_copies;
548
549	sector += stripe << geo->chunk_shift;
550
551	/* and calculate all the others */
552	for (n = 0; n < geo->near_copies; n++) {
553	int d = dev;
554	sector_t s = sector;
555	r10bio->devs[slot].addr = sector;
556	r10bio->devs[slot].devnum = d;
557	slot++;
558
559	for (f = 1; f < geo->far_copies; f++) {
560	d += geo->near_copies;
561	if (d >= geo->raid_disks)
562	d -= geo->raid_disks;
563	s += geo->stride;
564	r10bio->devs[slot].devnum = d;
565	r10bio->devs[slot].addr = s;
566	slot++;
567	}
568	dev++;
569	if (dev >= geo->raid_disks) {
570	dev = 0;
571	sector += (geo->chunk_mask + 1);
572	}
573	}
574	}
575
576	static void raid10_find_phys(struct r10conf conf, struct r10bio r10bio)
577	{
578	struct geom *geo = &conf->geo;
579
580	if (conf->reshape_progress != MaxSector &&
581	((r10bio->sector >= conf->reshape_progress) !=
582	conf->mddev->reshape_backwards)) {
583	set_bit(R10BIO_Previous, &r10bio->state);
584	geo = &conf->prev;
585	} else
586	clear_bit(R10BIO_Previous, &r10bio->state);
587
588	__raid10_find_phys(geo, r10bio);
589	}
590
591	static sector_t raid10_find_virt(struct r10conf *conf, sector_t sector, int dev)
592	{
593	sector_t offset, chunk, vchunk;
594	/* Never use conf->prev as this is only called during resync
595	* or recovery, so reshape isn't happening
596	*/
597	struct geom *geo = &conf->geo;
598
599	offset = sector & geo->chunk_mask;
600	if (geo->far_offset) {
601	int fc;
602	chunk = sector >> geo->chunk_shift;
603	fc = sector_div(chunk, geo->far_copies);
604	dev -= fc * geo->near_copies;
605	if (dev < 0)
606	dev += geo->raid_disks;
607	} else {
608	while (sector >= geo->stride) {
609	sector -= geo->stride;
610	if (dev < geo->near_copies)
611	dev += geo->raid_disks - geo->near_copies;
612	else
613	dev -= geo->near_copies;
614	}
615	chunk = sector >> geo->chunk_shift;
616	}
617	vchunk = chunk * geo->raid_disks + dev;
618	sector_div(vchunk, geo->near_copies);
619	return (vchunk << geo->chunk_shift) + offset;
620	}
621
622	/**
623	* raid10_mergeable_bvec -- tell bio layer if a two requests can be merged
624	* @q: request queue
625	* @bvm: properties of new bio
626	* @biovec: the request that could be merged to it.
627	*
628	* Return amount of bytes we can accept at this offset
629	* This requires checking for end-of-chunk if near_copies != raid_disks,
630	* and for subordinate merge_bvec_fns if merge_check_needed.
631	*/
632	static int raid10_mergeable_bvec(struct request_queue *q,
633	struct bvec_merge_data *bvm,
634	struct bio_vec *biovec)
635	{
636	struct mddev *mddev = q->queuedata;
637	struct r10conf *conf = mddev->private;
638	sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev);
639	int max;
640	unsigned int chunk_sectors;
641	unsigned int bio_sectors = bvm->bi_size >> 9;
642	struct geom *geo = &conf->geo;
643
644	chunk_sectors = (conf->geo.chunk_mask & conf->prev.chunk_mask) + 1;
645	if (conf->reshape_progress != MaxSector &&
646	((sector >= conf->reshape_progress) !=
647	conf->mddev->reshape_backwards))
648	geo = &conf->prev;
649
650	if (geo->near_copies < geo->raid_disks) {
651	max = (chunk_sectors - ((sector & (chunk_sectors - 1))
652	+ bio_sectors)) << 9;
653	if (max < 0)
654	/* bio_add cannot handle a negative return */
655	max = 0;
656	if (max <= biovec->bv_len && bio_sectors == 0)
657	return biovec->bv_len;
658	} else
659	max = biovec->bv_len;
660
661	if (mddev->merge_check_needed) {
662	struct {
663	struct r10bio r10_bio;
664	struct r10dev devs[conf->copies];
665	} on_stack;
666	struct r10bio *r10_bio = &on_stack.r10_bio;
667	int s;
668	if (conf->reshape_progress != MaxSector) {
669	/* Cannot give any guidance during reshape */
670	if (max <= biovec->bv_len && bio_sectors == 0)
671	return biovec->bv_len;
672	return 0;
673	}
674	r10_bio->sector = sector;
675	raid10_find_phys(conf, r10_bio);
676	rcu_read_lock();
677	for (s = 0; s < conf->copies; s++) {
678	int disk = r10_bio->devs[s].devnum;
679	struct md_rdev *rdev = rcu_dereference(
680	conf->mirrors[disk].rdev);
681	if (rdev && !test_bit(Faulty, &rdev->flags)) {
682	struct request_queue *q =
683	bdev_get_queue(rdev->bdev);
684	if (q->merge_bvec_fn) {
685	bvm->bi_sector = r10_bio->devs[s].addr
686	+ rdev->data_offset;
687	bvm->bi_bdev = rdev->bdev;
688	max = min(max, q->merge_bvec_fn(
689	q, bvm, biovec));
690	}
691	}
692	rdev = rcu_dereference(conf->mirrors[disk].replacement);
693	if (rdev && !test_bit(Faulty, &rdev->flags)) {
694	struct request_queue *q =
695	bdev_get_queue(rdev->bdev);
696	if (q->merge_bvec_fn) {
697	bvm->bi_sector = r10_bio->devs[s].addr
698	+ rdev->data_offset;
699	bvm->bi_bdev = rdev->bdev;
700	max = min(max, q->merge_bvec_fn(
701	q, bvm, biovec));
702	}
703	}
704	}
705	rcu_read_unlock();
706	}
707	return max;
708	}
709
710	/*
711	* This routine returns the disk from which the requested read should
712	* be done. There is a per-array 'next expected sequential IO' sector
713	* number - if this matches on the next IO then we use the last disk.
714	* There is also a per-disk 'last know head position' sector that is
715	* maintained from IRQ contexts, both the normal and the resync IO
716	* completion handlers update this position correctly. If there is no
717	* perfect sequential match then we pick the disk whose head is closest.
718	*
719	* If there are 2 mirrors in the same 2 devices, performance degrades
720	* because position is mirror, not device based.
721	*
722	* The rdev for the device selected will have nr_pending incremented.
723	*/
724
725	/*
726	* FIXME: possibly should rethink readbalancing and do it differently
727	* depending on near_copies / far_copies geometry.
728	*/
729	static struct md_rdev read_balance(struct r10conf conf,
730	struct r10bio *r10_bio,
731	int *max_sectors)
732	{
733	const sector_t this_sector = r10_bio->sector;
734	int disk, slot;
735	int sectors = r10_bio->sectors;
736	int best_good_sectors;
737	sector_t new_distance, best_dist;
738	struct md_rdev best_rdev, rdev = NULL;
739	int do_balance;
740	int best_slot;
741	struct geom *geo = &conf->geo;
742
743	raid10_find_phys(conf, r10_bio);
744	rcu_read_lock();
745	retry:
746	sectors = r10_bio->sectors;
747	best_slot = -1;
748	best_rdev = NULL;
749	best_dist = MaxSector;
750	best_good_sectors = 0;
751	do_balance = 1;
752	/*
753	* Check if we can balance. We can balance on the whole
754	* device if no resync is going on (recovery is ok), or below
755	* the resync window. We take the first readable disk when
756	* above the resync window.
757	*/
758	if (conf->mddev->recovery_cp < MaxSector
759	&& (this_sector + sectors >= conf->next_resync))
760	do_balance = 0;
761
762	for (slot = 0; slot < conf->copies ; slot++) {
763	sector_t first_bad;
764	int bad_sectors;
765	sector_t dev_sector;
766
767	if (r10_bio->devs[slot].bio == IO_BLOCKED)
768	continue;
769	disk = r10_bio->devs[slot].devnum;
770	rdev = rcu_dereference(conf->mirrors[disk].replacement);
771	if (rdev == NULL \|\| test_bit(Faulty, &rdev->flags) \|\|
772	test_bit(Unmerged, &rdev->flags) \|\|
773	r10_bio->devs[slot].addr + sectors > rdev->recovery_offset)
774	rdev = rcu_dereference(conf->mirrors[disk].rdev);
775	if (rdev == NULL \|\|
776	test_bit(Faulty, &rdev->flags) \|\|
777	test_bit(Unmerged, &rdev->flags))
778	continue;
779	if (!test_bit(In_sync, &rdev->flags) &&
780	r10_bio->devs[slot].addr + sectors > rdev->recovery_offset)
781	continue;
782
783	dev_sector = r10_bio->devs[slot].addr;
784	if (is_badblock(rdev, dev_sector, sectors,
785	&first_bad, &bad_sectors)) {
786	if (best_dist < MaxSector)
787	/* Already have a better slot */
788	continue;
789	if (first_bad <= dev_sector) {
790	/* Cannot read here. If this is the
791	* 'primary' device, then we must not read
792	* beyond 'bad_sectors' from another device.
793	*/
794	bad_sectors -= (dev_sector - first_bad);
795	if (!do_balance && sectors > bad_sectors)
796	sectors = bad_sectors;
797	if (best_good_sectors > sectors)
798	best_good_sectors = sectors;
799	} else {
800	sector_t good_sectors =
801	first_bad - dev_sector;
802	if (good_sectors > best_good_sectors) {
803	best_good_sectors = good_sectors;
804	best_slot = slot;
805	best_rdev = rdev;
806	}
807	if (!do_balance)
808	/* Must read from here */
809	break;
810	}
811	continue;
812	} else
813	best_good_sectors = sectors;
814
815	if (!do_balance)
816	break;
817
818	/* This optimisation is debatable, and completely destroys
819	* sequential read speed for 'far copies' arrays. So only
820	* keep it for 'near' arrays, and review those later.
821	*/
822	if (geo->near_copies > 1 && !atomic_read(&rdev->nr_pending))
823	break;
824
825	/* for far > 1 always use the lowest address */
826	if (geo->far_copies > 1)
827	new_distance = r10_bio->devs[slot].addr;
828	else
829	new_distance = abs(r10_bio->devs[slot].addr -
830	conf->mirrors[disk].head_position);
831	if (new_distance < best_dist) {
832	best_dist = new_distance;
833	best_slot = slot;
834	best_rdev = rdev;
835	}
836	}
837	if (slot >= conf->copies) {
838	slot = best_slot;
839	rdev = best_rdev;
840	}
841
842	if (slot >= 0) {
843	atomic_inc(&rdev->nr_pending);
844	if (test_bit(Faulty, &rdev->flags)) {
845	/* Cannot risk returning a device that failed
846	* before we inc'ed nr_pending
847	*/
848	rdev_dec_pending(rdev, conf->mddev);
849	goto retry;
850	}
851	r10_bio->read_slot = slot;
852	} else
853	rdev = NULL;
854	rcu_read_unlock();
855	*max_sectors = best_good_sectors;
856
857	return rdev;
858	}
859
860	int md_raid10_congested(struct mddev *mddev, int bits)
861	{
862	struct r10conf *conf = mddev->private;
863	int i, ret = 0;
864
865	if ((bits & (1 << BDI_async_congested)) &&
866	conf->pending_count >= max_queued_requests)
867	return 1;
868
869	rcu_read_lock();
870	for (i = 0;
871	(i < conf->geo.raid_disks \|\| i < conf->prev.raid_disks)
872	&& ret == 0;
873	i++) {
874	struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
875	if (rdev && !test_bit(Faulty, &rdev->flags)) {
876	struct request_queue *q = bdev_get_queue(rdev->bdev);
877
878	ret \|= bdi_congested(&q->backing_dev_info, bits);
879	}
880	}
881	rcu_read_unlock();
882	return ret;
883	}
884	EXPORT_SYMBOL_GPL(md_raid10_congested);
885
886	static int raid10_congested(void *data, int bits)
887	{
888	struct mddev *mddev = data;
889
890	return mddev_congested(mddev, bits) \|\|
891	md_raid10_congested(mddev, bits);
892	}
893
894	static void flush_pending_writes(struct r10conf *conf)
895	{
896	/* Any writes that have been queued but are awaiting
897	* bitmap updates get flushed here.
898	*/
899	spin_lock_irq(&conf->device_lock);
900
901	if (conf->pending_bio_list.head) {
902	struct bio *bio;
903	bio = bio_list_get(&conf->pending_bio_list);
904	conf->pending_count = 0;
905	spin_unlock_irq(&conf->device_lock);
906	/* flush any pending bitmap writes to disk
907	* before proceeding w/ I/O */
908	bitmap_unplug(conf->mddev->bitmap);
909	wake_up(&conf->wait_barrier);
910
911	while (bio) { /* submit pending writes */
912	struct bio *next = bio->bi_next;
913	bio->bi_next = NULL;
914	generic_make_request(bio);
915	bio = next;
916	}
917	} else
918	spin_unlock_irq(&conf->device_lock);
919	}
920
921	/* Barriers....
922	* Sometimes we need to suspend IO while we do something else,
923	* either some resync/recovery, or reconfigure the array.
924	* To do this we raise a 'barrier'.
925	* The 'barrier' is a counter that can be raised multiple times
926	* to count how many activities are happening which preclude
927	* normal IO.
928	* We can only raise the barrier if there is no pending IO.
929	* i.e. if nr_pending == 0.
930	* We choose only to raise the barrier if no-one is waiting for the
931	* barrier to go down. This means that as soon as an IO request
932	* is ready, no other operations which require a barrier will start
933	* until the IO request has had a chance.
934	*
935	* So: regular IO calls 'wait_barrier'. When that returns there
936	* is no backgroup IO happening, It must arrange to call
937	* allow_barrier when it has finished its IO.
938	* backgroup IO calls must call raise_barrier. Once that returns
939	* there is no normal IO happeing. It must arrange to call
940	* lower_barrier when the particular background IO completes.
941	*/
942
943	static void raise_barrier(struct r10conf *conf, int force)
944	{
945	BUG_ON(force && !conf->barrier);
946	spin_lock_irq(&conf->resync_lock);
947
948	/* Wait until no block IO is waiting (unless 'force') */
949	wait_event_lock_irq(conf->wait_barrier, force \|\| !conf->nr_waiting,
950	conf->resync_lock, );
951
952	/* block any new IO from starting */
953	conf->barrier++;
954
955	/* Now wait for all pending IO to complete */
956	wait_event_lock_irq(conf->wait_barrier,
957	!conf->nr_pending && conf->barrier < RESYNC_DEPTH,
958	conf->resync_lock, );
959
960	spin_unlock_irq(&conf->resync_lock);
961	}
962
963	static void lower_barrier(struct r10conf *conf)
964	{
965	unsigned long flags;
966	spin_lock_irqsave(&conf->resync_lock, flags);
967	conf->barrier--;
968	spin_unlock_irqrestore(&conf->resync_lock, flags);
969	wake_up(&conf->wait_barrier);
970	}
971
972	static void wait_barrier(struct r10conf *conf)
973	{
974	spin_lock_irq(&conf->resync_lock);
975	if (conf->barrier) {
976	conf->nr_waiting++;
977	/* Wait for the barrier to drop.
978	* However if there are already pending
979	* requests (preventing the barrier from
980	* rising completely), and the
981	* pre-process bio queue isn't empty,
982	* then don't wait, as we need to empty
983	* that queue to get the nr_pending
984	* count down.
985	*/
986	wait_event_lock_irq(conf->wait_barrier,
987	!conf->barrier \|\|
988	(conf->nr_pending &&
989	current->bio_list &&
990	!bio_list_empty(current->bio_list)),
991	conf->resync_lock,
992	);
993	conf->nr_waiting--;
994	}
995	conf->nr_pending++;
996	spin_unlock_irq(&conf->resync_lock);
997	}
998
999	static void allow_barrier(struct r10conf *conf)
1000	{
1001	unsigned long flags;
1002	spin_lock_irqsave(&conf->resync_lock, flags);
1003	conf->nr_pending--;
1004	spin_unlock_irqrestore(&conf->resync_lock, flags);
1005	wake_up(&conf->wait_barrier);
1006	}
1007
1008	static void freeze_array(struct r10conf *conf)
1009	{
1010	/* stop syncio and normal IO and wait for everything to
1011	* go quiet.
1012	* We increment barrier and nr_waiting, and then
1013	* wait until nr_pending match nr_queued+1
1014	* This is called in the context of one normal IO request
1015	* that has failed. Thus any sync request that might be pending
1016	* will be blocked by nr_pending, and we need to wait for
1017	* pending IO requests to complete or be queued for re-try.
1018	* Thus the number queued (nr_queued) plus this request (1)
1019	* must match the number of pending IOs (nr_pending) before
1020	* we continue.
1021	*/
1022	spin_lock_irq(&conf->resync_lock);
1023	conf->barrier++;
1024	conf->nr_waiting++;
1025	wait_event_lock_irq(conf->wait_barrier,
1026	conf->nr_pending == conf->nr_queued+1,
1027	conf->resync_lock,
1028	flush_pending_writes(conf));
1029
1030	spin_unlock_irq(&conf->resync_lock);
1031	}
1032
1033	static void unfreeze_array(struct r10conf *conf)
1034	{
1035	/* reverse the effect of the freeze */
1036	spin_lock_irq(&conf->resync_lock);
1037	conf->barrier--;
1038	conf->nr_waiting--;
1039	wake_up(&conf->wait_barrier);
1040	spin_unlock_irq(&conf->resync_lock);
1041	}
1042
1043	static sector_t choose_data_offset(struct r10bio *r10_bio,
1044	struct md_rdev *rdev)
1045	{
1046	if (!test_bit(MD_RECOVERY_RESHAPE, &rdev->mddev->recovery) \|\|
1047	test_bit(R10BIO_Previous, &r10_bio->state))
1048	return rdev->data_offset;
1049	else
1050	return rdev->new_data_offset;
1051	}
1052
1053	static void make_request(struct mddev mddev, struct bio bio)
1054	{
1055	struct r10conf *conf = mddev->private;
1056	struct r10bio *r10_bio;
1057	struct bio *read_bio;
1058	int i;
1059	sector_t chunk_mask = (conf->geo.chunk_mask & conf->prev.chunk_mask);
1060	int chunk_sects = chunk_mask + 1;
1061	const int rw = bio_data_dir(bio);
1062	const unsigned long do_sync = (bio->bi_rw & REQ_SYNC);
1063	const unsigned long do_fua = (bio->bi_rw & REQ_FUA);
1064	unsigned long flags;
1065	struct md_rdev *blocked_rdev;
1066	int sectors_handled;
1067	int max_sectors;
1068	int sectors;
1069
1070	if (unlikely(bio->bi_rw & REQ_FLUSH)) {
1071	md_flush_request(mddev, bio);
1072	return;
1073	}
1074
1075	/* If this request crosses a chunk boundary, we need to
1076	* split it. This will only happen for 1 PAGE (or less) requests.
1077	*/
1078	if (unlikely((bio->bi_sector & chunk_mask) + (bio->bi_size >> 9)
1079	> chunk_sects
1080	&& (conf->geo.near_copies < conf->geo.raid_disks
1081	\|\| conf->prev.near_copies < conf->prev.raid_disks))) {
1082	struct bio_pair *bp;
1083	/* Sanity check -- queue functions should prevent this happening */
1084	if (bio->bi_vcnt != 1 \|\|
1085	bio->bi_idx != 0)
1086	goto bad_map;
1087	/* This is a one page bio that upper layers
1088	* refuse to split for us, so we need to split it.
1089	*/
1090	bp = bio_split(bio,
1091	chunk_sects - (bio->bi_sector & (chunk_sects - 1)) );
1092
1093	/* Each of these 'make_request' calls will call 'wait_barrier'.
1094	* If the first succeeds but the second blocks due to the resync
1095	* thread raising the barrier, we will deadlock because the
1096	* IO to the underlying device will be queued in generic_make_request
1097	* and will never complete, so will never reduce nr_pending.
1098	* So increment nr_waiting here so no new raise_barriers will
1099	* succeed, and so the second wait_barrier cannot block.
1100	*/
1101	spin_lock_irq(&conf->resync_lock);
1102	conf->nr_waiting++;
1103	spin_unlock_irq(&conf->resync_lock);
1104
1105	make_request(mddev, &bp->bio1);
1106	make_request(mddev, &bp->bio2);
1107
1108	spin_lock_irq(&conf->resync_lock);
1109	conf->nr_waiting--;
1110	wake_up(&conf->wait_barrier);
1111	spin_unlock_irq(&conf->resync_lock);
1112
1113	bio_pair_release(bp);
1114	return;
1115	bad_map:
1116	printk("md/raid10:%s: make_request bug: can't convert block across chunks"
1117	" or bigger than %dk %llu %d\n", mdname(mddev), chunk_sects/2,
1118	(unsigned long long)bio->bi_sector, bio->bi_size >> 10);
1119
1120	bio_io_error(bio);
1121	return;
1122	}
1123
1124	md_write_start(mddev, bio);
1125
1126	/*
1127	* Register the new request and wait if the reconstruction
1128	* thread has put up a bar for new requests.
1129	* Continue immediately if no resync is active currently.
1130	*/
1131	wait_barrier(conf);
1132
1133	sectors = bio->bi_size >> 9;
1134	while (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
1135	bio->bi_sector < conf->reshape_progress &&
1136	bio->bi_sector + sectors > conf->reshape_progress) {
1137	/* IO spans the reshape position. Need to wait for
1138	* reshape to pass
1139	*/
1140	allow_barrier(conf);
1141	wait_event(conf->wait_barrier,
1142	conf->reshape_progress <= bio->bi_sector \|\|
1143	conf->reshape_progress >= bio->bi_sector + sectors);
1144	wait_barrier(conf);
1145	}
1146	if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
1147	bio_data_dir(bio) == WRITE &&
1148	(mddev->reshape_backwards
1149	? (bio->bi_sector < conf->reshape_safe &&
1150	bio->bi_sector + sectors > conf->reshape_progress)
1151	: (bio->bi_sector + sectors > conf->reshape_safe &&
1152	bio->bi_sector < conf->reshape_progress))) {
1153	/* Need to update reshape_position in metadata */
1154	mddev->reshape_position = conf->reshape_progress;
1155	set_bit(MD_CHANGE_DEVS, &mddev->flags);
1156	set_bit(MD_CHANGE_PENDING, &mddev->flags);
1157	md_wakeup_thread(mddev->thread);
1158	wait_event(mddev->sb_wait,
1159	!test_bit(MD_CHANGE_PENDING, &mddev->flags));
1160
1161	conf->reshape_safe = mddev->reshape_position;
1162	}
1163
1164	r10_bio = mempool_alloc(conf->r10bio_pool, GFP_NOIO);
1165
1166	r10_bio->master_bio = bio;
1167	r10_bio->sectors = sectors;
1168
1169	r10_bio->mddev = mddev;
1170	r10_bio->sector = bio->bi_sector;
1171	r10_bio->state = 0;
1172
1173	/* We might need to issue multiple reads to different
1174	* devices if there are bad blocks around, so we keep
1175	* track of the number of reads in bio->bi_phys_segments.
1176	* If this is 0, there is only one r10_bio and no locking
1177	* will be needed when the request completes. If it is
1178	* non-zero, then it is the number of not-completed requests.
1179	*/
1180	bio->bi_phys_segments = 0;
1181	clear_bit(BIO_SEG_VALID, &bio->bi_flags);
1182
1183	if (rw == READ) {
1184	/*
1185	* read balancing logic:
1186	*/
1187	struct md_rdev *rdev;
1188	int slot;
1189
1190	read_again:
1191	rdev = read_balance(conf, r10_bio, &max_sectors);
1192	if (!rdev) {
1193	raid_end_bio_io(r10_bio);
1194	return;
1195	}
1196	slot = r10_bio->read_slot;
1197
1198	read_bio = bio_clone_mddev(bio, GFP_NOIO, mddev);
1199	md_trim_bio(read_bio, r10_bio->sector - bio->bi_sector,
1200	max_sectors);
1201
1202	r10_bio->devs[slot].bio = read_bio;
1203	r10_bio->devs[slot].rdev = rdev;
1204
1205	read_bio->bi_sector = r10_bio->devs[slot].addr +
1206	choose_data_offset(r10_bio, rdev);
1207	read_bio->bi_bdev = rdev->bdev;
1208	read_bio->bi_end_io = raid10_end_read_request;
1209	read_bio->bi_rw = READ \| do_sync;
1210	read_bio->bi_private = r10_bio;
1211
1212	if (max_sectors < r10_bio->sectors) {
1213	/* Could not read all from this device, so we will
1214	* need another r10_bio.
1215	*/
1216	sectors_handled = (r10_bio->sectors + max_sectors
1217	- bio->bi_sector);
1218	r10_bio->sectors = max_sectors;
1219	spin_lock_irq(&conf->device_lock);
1220	if (bio->bi_phys_segments == 0)
1221	bio->bi_phys_segments = 2;
1222	else
1223	bio->bi_phys_segments++;
1224	spin_unlock(&conf->device_lock);
1225	/* Cannot call generic_make_request directly
1226	* as that will be queued in __generic_make_request
1227	* and subsequent mempool_alloc might block
1228	* waiting for it. so hand bio over to raid10d.
1229	*/
1230	reschedule_retry(r10_bio);
1231
1232	r10_bio = mempool_alloc(conf->r10bio_pool, GFP_NOIO);
1233
1234	r10_bio->master_bio = bio;
1235	r10_bio->sectors = ((bio->bi_size >> 9)
1236	- sectors_handled);
1237	r10_bio->state = 0;
1238	r10_bio->mddev = mddev;
1239	r10_bio->sector = bio->bi_sector + sectors_handled;
1240	goto read_again;
1241	} else
1242	generic_make_request(read_bio);
1243	return;
1244	}
1245
1246	/*
1247	* WRITE:
1248	*/
1249	if (conf->pending_count >= max_queued_requests) {
1250	md_wakeup_thread(mddev->thread);
1251	wait_event(conf->wait_barrier,
1252	conf->pending_count < max_queued_requests);
1253	}
1254	/* first select target devices under rcu_lock and
1255	* inc refcount on their rdev. Record them by setting
1256	* bios[x] to bio
1257	* If there are known/acknowledged bad blocks on any device
1258	* on which we have seen a write error, we want to avoid
1259	* writing to those blocks. This potentially requires several
1260	* writes to write around the bad blocks. Each set of writes
1261	* gets its own r10_bio with a set of bios attached. The number
1262	* of r10_bios is recored in bio->bi_phys_segments just as with
1263	* the read case.
1264	*/
1265
1266	r10_bio->read_slot = -1; /* make sure repl_bio gets freed */
1267	raid10_find_phys(conf, r10_bio);
1268	retry_write:
1269	blocked_rdev = NULL;
1270	rcu_read_lock();
1271	max_sectors = r10_bio->sectors;
1272
1273	for (i = 0; i < conf->copies; i++) {
1274	int d = r10_bio->devs[i].devnum;
1275	struct md_rdev *rdev = rcu_dereference(conf->mirrors[d].rdev);
1276	struct md_rdev *rrdev = rcu_dereference(
1277	conf->mirrors[d].replacement);
1278	if (rdev == rrdev)
1279	rrdev = NULL;
1280	if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) {
1281	atomic_inc(&rdev->nr_pending);
1282	blocked_rdev = rdev;
1283	break;
1284	}
1285	if (rrdev && unlikely(test_bit(Blocked, &rrdev->flags))) {
1286	atomic_inc(&rrdev->nr_pending);
1287	blocked_rdev = rrdev;
1288	break;
1289	}
1290	if (rrdev && (test_bit(Faulty, &rrdev->flags)
1291	\|\| test_bit(Unmerged, &rrdev->flags)))
1292	rrdev = NULL;
1293
1294	r10_bio->devs[i].bio = NULL;
1295	r10_bio->devs[i].repl_bio = NULL;
1296	if (!rdev \|\| test_bit(Faulty, &rdev->flags) \|\|
1297	test_bit(Unmerged, &rdev->flags)) {
1298	set_bit(R10BIO_Degraded, &r10_bio->state);
1299	continue;
1300	}
1301	if (test_bit(WriteErrorSeen, &rdev->flags)) {
1302	sector_t first_bad;
1303	sector_t dev_sector = r10_bio->devs[i].addr;
1304	int bad_sectors;
1305	int is_bad;
1306
1307	is_bad = is_badblock(rdev, dev_sector,
1308	max_sectors,
1309	&first_bad, &bad_sectors);
1310	if (is_bad < 0) {
1311	/* Mustn't write here until the bad block
1312	* is acknowledged
1313	*/
1314	atomic_inc(&rdev->nr_pending);
1315	set_bit(BlockedBadBlocks, &rdev->flags);
1316	blocked_rdev = rdev;
1317	break;
1318	}
1319	if (is_bad && first_bad <= dev_sector) {
1320	/* Cannot write here at all */
1321	bad_sectors -= (dev_sector - first_bad);
1322	if (bad_sectors < max_sectors)
1323	/* Mustn't write more than bad_sectors
1324	* to other devices yet
1325	*/
1326	max_sectors = bad_sectors;
1327	/* We don't set R10BIO_Degraded as that
1328	* only applies if the disk is missing,
1329	* so it might be re-added, and we want to
1330	* know to recover this chunk.
1331	* In this case the device is here, and the
1332	* fact that this chunk is not in-sync is
1333	* recorded in the bad block log.
1334	*/
1335	continue;
1336	}
1337	if (is_bad) {
1338	int good_sectors = first_bad - dev_sector;
1339	if (good_sectors < max_sectors)
1340	max_sectors = good_sectors;
1341	}
1342	}
1343	r10_bio->devs[i].bio = bio;
1344	atomic_inc(&rdev->nr_pending);
1345	if (rrdev) {
1346	r10_bio->devs[i].repl_bio = bio;
1347	atomic_inc(&rrdev->nr_pending);
1348	}
1349	}
1350	rcu_read_unlock();
1351
1352	if (unlikely(blocked_rdev)) {
1353	/* Have to wait for this device to get unblocked, then retry */
1354	int j;
1355	int d;
1356
1357	for (j = 0; j < i; j++) {
1358	if (r10_bio->devs[j].bio) {
1359	d = r10_bio->devs[j].devnum;
1360	rdev_dec_pending(conf->mirrors[d].rdev, mddev);
1361	}
1362	if (r10_bio->devs[j].repl_bio) {
1363	struct md_rdev *rdev;
1364	d = r10_bio->devs[j].devnum;
1365	rdev = conf->mirrors[d].replacement;
1366	if (!rdev) {
1367	/* Race with remove_disk */
1368	smp_mb();
1369	rdev = conf->mirrors[d].rdev;
1370	}
1371	rdev_dec_pending(rdev, mddev);
1372	}
1373	}
1374	allow_barrier(conf);
1375	md_wait_for_blocked_rdev(blocked_rdev, mddev);
1376	wait_barrier(conf);
1377	goto retry_write;
1378	}
1379
1380	if (max_sectors < r10_bio->sectors) {
1381	/* We are splitting this into multiple parts, so
1382	* we need to prepare for allocating another r10_bio.
1383	*/
1384	r10_bio->sectors = max_sectors;
1385	spin_lock_irq(&conf->device_lock);
1386	if (bio->bi_phys_segments == 0)
1387	bio->bi_phys_segments = 2;
1388	else
1389	bio->bi_phys_segments++;
1390	spin_unlock_irq(&conf->device_lock);
1391	}
1392	sectors_handled = r10_bio->sector + max_sectors - bio->bi_sector;
1393
1394	atomic_set(&r10_bio->remaining, 1);
1395	bitmap_startwrite(mddev->bitmap, r10_bio->sector, r10_bio->sectors, 0);
1396
1397	for (i = 0; i < conf->copies; i++) {
1398	struct bio *mbio;
1399	int d = r10_bio->devs[i].devnum;
1400	if (!r10_bio->devs[i].bio)
1401	continue;
1402
1403	mbio = bio_clone_mddev(bio, GFP_NOIO, mddev);
1404	md_trim_bio(mbio, r10_bio->sector - bio->bi_sector,
1405	max_sectors);
1406	r10_bio->devs[i].bio = mbio;
1407
1408	mbio->bi_sector = (r10_bio->devs[i].addr+
1409	choose_data_offset(r10_bio,
1410	conf->mirrors[d].rdev));
1411	mbio->bi_bdev = conf->mirrors[d].rdev->bdev;
1412	mbio->bi_end_io = raid10_end_write_request;
1413	mbio->bi_rw = WRITE \| do_sync \| do_fua;
1414	mbio->bi_private = r10_bio;
1415
1416	atomic_inc(&r10_bio->remaining);
1417	spin_lock_irqsave(&conf->device_lock, flags);
1418	bio_list_add(&conf->pending_bio_list, mbio);
1419	conf->pending_count++;
1420	spin_unlock_irqrestore(&conf->device_lock, flags);
1421	if (!mddev_check_plugged(mddev))
1422	md_wakeup_thread(mddev->thread);
1423
1424	if (!r10_bio->devs[i].repl_bio)
1425	continue;
1426
1427	mbio = bio_clone_mddev(bio, GFP_NOIO, mddev);
1428	md_trim_bio(mbio, r10_bio->sector - bio->bi_sector,
1429	max_sectors);
1430	r10_bio->devs[i].repl_bio = mbio;
1431
1432	/* We are actively writing to the original device
1433	* so it cannot disappear, so the replacement cannot
1434	* become NULL here
1435	*/
1436	mbio->bi_sector = (r10_bio->devs[i].addr +
1437	choose_data_offset(
1438	r10_bio,
1439	conf->mirrors[d].replacement));
1440	mbio->bi_bdev = conf->mirrors[d].replacement->bdev;
1441	mbio->bi_end_io = raid10_end_write_request;
1442	mbio->bi_rw = WRITE \| do_sync \| do_fua;
1443	mbio->bi_private = r10_bio;
1444
1445	atomic_inc(&r10_bio->remaining);
1446	spin_lock_irqsave(&conf->device_lock, flags);
1447	bio_list_add(&conf->pending_bio_list, mbio);
1448	conf->pending_count++;
1449	spin_unlock_irqrestore(&conf->device_lock, flags);
1450	if (!mddev_check_plugged(mddev))
1451	md_wakeup_thread(mddev->thread);
1452	}
1453
1454	/* Don't remove the bias on 'remaining' (one_write_done) until
1455	* after checking if we need to go around again.
1456	*/
1457
1458	if (sectors_handled < (bio->bi_size >> 9)) {
1459	one_write_done(r10_bio);
1460	/* We need another r10_bio. It has already been counted
1461	* in bio->bi_phys_segments.
1462	*/
1463	r10_bio = mempool_alloc(conf->r10bio_pool, GFP_NOIO);
1464
1465	r10_bio->master_bio = bio;
1466	r10_bio->sectors = (bio->bi_size >> 9) - sectors_handled;
1467
1468	r10_bio->mddev = mddev;
1469	r10_bio->sector = bio->bi_sector + sectors_handled;
1470	r10_bio->state = 0;
1471	goto retry_write;
1472	}
1473	one_write_done(r10_bio);
1474
1475	/* In case raid10d snuck in to freeze_array */
1476	wake_up(&conf->wait_barrier);
1477	}
1478
1479	static void status(struct seq_file seq, struct mddev mddev)
1480	{
1481	struct r10conf *conf = mddev->private;
1482	int i;
1483
1484	if (conf->geo.near_copies < conf->geo.raid_disks)
1485	seq_printf(seq, " %dK chunks", mddev->chunk_sectors / 2);
1486	if (conf->geo.near_copies > 1)
1487	seq_printf(seq, " %d near-copies", conf->geo.near_copies);
1488	if (conf->geo.far_copies > 1) {
1489	if (conf->geo.far_offset)
1490	seq_printf(seq, " %d offset-copies", conf->geo.far_copies);
1491	else
1492	seq_printf(seq, " %d far-copies", conf->geo.far_copies);
1493	}
1494	seq_printf(seq, " [%d/%d] [", conf->geo.raid_disks,
1495	conf->geo.raid_disks - mddev->degraded);
1496	for (i = 0; i < conf->geo.raid_disks; i++)
1497	seq_printf(seq, "%s",
1498	conf->mirrors[i].rdev &&
1499	test_bit(In_sync, &conf->mirrors[i].rdev->flags) ? "U" : "_");
1500	seq_printf(seq, "]");
1501	}
1502
1503	/* check if there are enough drives for
1504	* every block to appear on atleast one.
1505	* Don't consider the device numbered 'ignore'
1506	* as we might be about to remove it.
1507	*/
1508	static int _enough(struct r10conf conf, struct geom geo, int ignore)
1509	{
1510	int first = 0;
1511
1512	do {
1513	int n = conf->copies;
1514	int cnt = 0;
1515	int this = first;
1516	while (n--) {
1517	if (conf->mirrors[this].rdev &&
1518	this != ignore)
1519	cnt++;
1520	this = (this+1) % geo->raid_disks;
1521	}
1522	if (cnt == 0)
1523	return 0;
1524	first = (first + geo->near_copies) % geo->raid_disks;
1525	} while (first != 0);
1526	return 1;
1527	}
1528
1529	static int enough(struct r10conf *conf, int ignore)
1530	{
1531	return _enough(conf, &conf->geo, ignore) &&
1532	_enough(conf, &conf->prev, ignore);
1533	}
1534
1535	static void error(struct mddev mddev, struct md_rdev rdev)
1536	{
1537	char b[BDEVNAME_SIZE];
1538	struct r10conf *conf = mddev->private;
1539
1540	/*
1541	* If it is not operational, then we have already marked it as dead
1542	* else if it is the last working disks, ignore the error, let the
1543	* next level up know.
1544	* else mark the drive as failed
1545	*/
1546	if (test_bit(In_sync, &rdev->flags)
1547	&& !enough(conf, rdev->raid_disk))
1548	/*
1549	* Don't fail the drive, just return an IO error.
1550	*/
1551	return;
1552	if (test_and_clear_bit(In_sync, &rdev->flags)) {
1553	unsigned long flags;
1554	spin_lock_irqsave(&conf->device_lock, flags);
1555	mddev->degraded++;
1556	spin_unlock_irqrestore(&conf->device_lock, flags);
1557	/*
1558	* if recovery is running, make sure it aborts.
1559	*/
1560	set_bit(MD_RECOVERY_INTR, &mddev->recovery);
1561	}
1562	set_bit(Blocked, &rdev->flags);
1563	set_bit(Faulty, &rdev->flags);
1564	set_bit(MD_CHANGE_DEVS, &mddev->flags);
1565	printk(KERN_ALERT
1566	"md/raid10:%s: Disk failure on %s, disabling device.\n"
1567	"md/raid10:%s: Operation continuing on %d devices.\n",
1568	mdname(mddev), bdevname(rdev->bdev, b),
1569	mdname(mddev), conf->geo.raid_disks - mddev->degraded);
1570	}
1571
1572	static void print_conf(struct r10conf *conf)
1573	{
1574	int i;
1575	struct raid10_info *tmp;
1576
1577	printk(KERN_DEBUG "RAID10 conf printout:\n");
1578	if (!conf) {
1579	printk(KERN_DEBUG "(!conf)\n");
1580	return;
1581	}
1582	printk(KERN_DEBUG " --- wd:%d rd:%d\n", conf->geo.raid_disks - conf->mddev->degraded,
1583	conf->geo.raid_disks);
1584
1585	for (i = 0; i < conf->geo.raid_disks; i++) {
1586	char b[BDEVNAME_SIZE];
1587	tmp = conf->mirrors + i;
1588	if (tmp->rdev)
1589	printk(KERN_DEBUG " disk %d, wo:%d, o:%d, dev:%s\n",
1590	i, !test_bit(In_sync, &tmp->rdev->flags),
1591	!test_bit(Faulty, &tmp->rdev->flags),
1592	bdevname(tmp->rdev->bdev,b));
1593	}
1594	}
1595
1596	static void close_sync(struct r10conf *conf)
1597	{
1598	wait_barrier(conf);
1599	allow_barrier(conf);
1600
1601	mempool_destroy(conf->r10buf_pool);
1602	conf->r10buf_pool = NULL;
1603	}
1604
1605	static int raid10_spare_active(struct mddev *mddev)
1606	{
1607	int i;
1608	struct r10conf *conf = mddev->private;
1609	struct raid10_info *tmp;
1610	int count = 0;
1611	unsigned long flags;
1612
1613	/*
1614	* Find all non-in_sync disks within the RAID10 configuration
1615	* and mark them in_sync
1616	*/
1617	for (i = 0; i < conf->geo.raid_disks; i++) {
1618	tmp = conf->mirrors + i;
1619	if (tmp->replacement
1620	&& tmp->replacement->recovery_offset == MaxSector
1621	&& !test_bit(Faulty, &tmp->replacement->flags)
1622	&& !test_and_set_bit(In_sync, &tmp->replacement->flags)) {
1623	/* Replacement has just become active */
1624	if (!tmp->rdev
1625	\|\| !test_and_clear_bit(In_sync, &tmp->rdev->flags))
1626	count++;
1627	if (tmp->rdev) {
1628	/* Replaced device not technically faulty,
1629	* but we need to be sure it gets removed
1630	* and never re-added.
1631	*/
1632	set_bit(Faulty, &tmp->rdev->flags);
1633	sysfs_notify_dirent_safe(
1634	tmp->rdev->sysfs_state);
1635	}
1636	sysfs_notify_dirent_safe(tmp->replacement->sysfs_state);
1637	} else if (tmp->rdev
1638	&& !test_bit(Faulty, &tmp->rdev->flags)
1639	&& !test_and_set_bit(In_sync, &tmp->rdev->flags)) {
1640	count++;
1641	sysfs_notify_dirent(tmp->rdev->sysfs_state);
1642	}
1643	}
1644	spin_lock_irqsave(&conf->device_lock, flags);
1645	mddev->degraded -= count;
1646	spin_unlock_irqrestore(&conf->device_lock, flags);
1647
1648	print_conf(conf);
1649	return count;
1650	}
1651
1652
1653	static int raid10_add_disk(struct mddev mddev, struct md_rdev rdev)
1654	{
1655	struct r10conf *conf = mddev->private;
1656	int err = -EEXIST;
1657	int mirror;
1658	int first = 0;
1659	int last = conf->geo.raid_disks - 1;
1660	struct request_queue *q = bdev_get_queue(rdev->bdev);
1661
1662	if (mddev->recovery_cp < MaxSector)
1663	/* only hot-add to in-sync arrays, as recovery is
1664	* very different from resync
1665	*/
1666	return -EBUSY;
1667	if (rdev->saved_raid_disk < 0 && !_enough(conf, &conf->prev, -1))
1668	return -EINVAL;
1669
1670	if (rdev->raid_disk >= 0)
1671	first = last = rdev->raid_disk;
1672
1673	if (q->merge_bvec_fn) {
1674	set_bit(Unmerged, &rdev->flags);
1675	mddev->merge_check_needed = 1;
1676	}
1677
1678	if (rdev->saved_raid_disk >= first &&
1679	conf->mirrors[rdev->saved_raid_disk].rdev == NULL)
1680	mirror = rdev->saved_raid_disk;
1681	else
1682	mirror = first;
1683	for ( ; mirror <= last ; mirror++) {
1684	struct raid10_info *p = &conf->mirrors[mirror];
1685	if (p->recovery_disabled == mddev->recovery_disabled)
1686	continue;
1687	if (p->rdev) {
1688	if (!test_bit(WantReplacement, &p->rdev->flags) \|\|
1689	p->replacement != NULL)
1690	continue;
1691	clear_bit(In_sync, &rdev->flags);
1692	set_bit(Replacement, &rdev->flags);
1693	rdev->raid_disk = mirror;
1694	err = 0;
1695	disk_stack_limits(mddev->gendisk, rdev->bdev,
1696	rdev->data_offset << 9);
1697	conf->fullsync = 1;
1698	rcu_assign_pointer(p->replacement, rdev);
1699	break;
1700	}
1701
1702	disk_stack_limits(mddev->gendisk, rdev->bdev,
1703	rdev->data_offset << 9);
1704
1705	p->head_position = 0;
1706	p->recovery_disabled = mddev->recovery_disabled - 1;
1707	rdev->raid_disk = mirror;
1708	err = 0;
1709	if (rdev->saved_raid_disk != mirror)
1710	conf->fullsync = 1;
1711	rcu_assign_pointer(p->rdev, rdev);
1712	break;
1713	}
1714	if (err == 0 && test_bit(Unmerged, &rdev->flags)) {
1715	/* Some requests might not have seen this new
1716	* merge_bvec_fn. We must wait for them to complete
1717	* before merging the device fully.
1718	* First we make sure any code which has tested
1719	* our function has submitted the request, then
1720	* we wait for all outstanding requests to complete.
1721	*/
1722	synchronize_sched();
1723	raise_barrier(conf, 0);
1724	lower_barrier(conf);
1725	clear_bit(Unmerged, &rdev->flags);
1726	}
1727	md_integrity_add_rdev(rdev, mddev);
1728	print_conf(conf);
1729	return err;
1730	}
1731
1732	static int raid10_remove_disk(struct mddev mddev, struct md_rdev rdev)
1733	{
1734	struct r10conf *conf = mddev->private;
1735	int err = 0;
1736	int number = rdev->raid_disk;
1737	struct md_rdev **rdevp;
1738	struct raid10_info *p = conf->mirrors + number;
1739
1740	print_conf(conf);
1741	if (rdev == p->rdev)
1742	rdevp = &p->rdev;
1743	else if (rdev == p->replacement)
1744	rdevp = &p->replacement;
1745	else
1746	return 0;
1747
1748	if (test_bit(In_sync, &rdev->flags) \|\|
1749	atomic_read(&rdev->nr_pending)) {
1750	err = -EBUSY;
1751	goto abort;
1752	}
1753	/* Only remove faulty devices if recovery
1754	* is not possible.
1755	*/
1756	if (!test_bit(Faulty, &rdev->flags) &&
1757	mddev->recovery_disabled != p->recovery_disabled &&
1758	(!p->replacement \|\| p->replacement == rdev) &&
1759	number < conf->geo.raid_disks &&
1760	enough(conf, -1)) {
1761	err = -EBUSY;
1762	goto abort;
1763	}
1764	*rdevp = NULL;
1765	synchronize_rcu();
1766	if (atomic_read(&rdev->nr_pending)) {
1767	/* lost the race, try later */
1768	err = -EBUSY;
1769	*rdevp = rdev;
1770	goto abort;
1771	} else if (p->replacement) {
1772	/* We must have just cleared 'rdev' */
1773	p->rdev = p->replacement;
1774	clear_bit(Replacement, &p->replacement->flags);
1775	smp_mb(); /* Make sure other CPUs may see both as identical
1776	* but will never see neither -- if they are careful.
1777	*/
1778	p->replacement = NULL;
1779	clear_bit(WantReplacement, &rdev->flags);
1780	} else
1781	/* We might have just remove the Replacement as faulty
1782	* Clear the flag just in case
1783	*/
1784	clear_bit(WantReplacement, &rdev->flags);
1785
1786	err = md_integrity_register(mddev);
1787
1788	abort:
1789
1790	print_conf(conf);
1791	return err;
1792	}
1793
1794
1795	static void end_sync_read(struct bio *bio, int error)
1796	{
1797	struct r10bio *r10_bio = bio->bi_private;
1798	struct r10conf *conf = r10_bio->mddev->private;
1799	int d;
1800
1801	if (bio == r10_bio->master_bio) {
1802	/* this is a reshape read */
1803	d = r10_bio->read_slot; /* really the read dev */
1804	} else
1805	d = find_bio_disk(conf, r10_bio, bio, NULL, NULL);
1806
1807	if (test_bit(BIO_UPTODATE, &bio->bi_flags))
1808	set_bit(R10BIO_Uptodate, &r10_bio->state);
1809	else
1810	/* The write handler will notice the lack of
1811	* R10BIO_Uptodate and record any errors etc
1812	*/
1813	atomic_add(r10_bio->sectors,
1814	&conf->mirrors[d].rdev->corrected_errors);
1815
1816	/* for reconstruct, we always reschedule after a read.
1817	* for resync, only after all reads
1818	*/
1819	rdev_dec_pending(conf->mirrors[d].rdev, conf->mddev);
1820	if (test_bit(R10BIO_IsRecover, &r10_bio->state) \|\|
1821	atomic_dec_and_test(&r10_bio->remaining)) {
1822	/* we have read all the blocks,
1823	* do the comparison in process context in raid10d
1824	*/
1825	reschedule_retry(r10_bio);
1826	}
1827	}
1828
1829	static void end_sync_request(struct r10bio *r10_bio)
1830	{
1831	struct mddev *mddev = r10_bio->mddev;
1832
1833	while (atomic_dec_and_test(&r10_bio->remaining)) {
1834	if (r10_bio->master_bio == NULL) {
1835	/* the primary of several recovery bios */
1836	sector_t s = r10_bio->sectors;
1837	if (test_bit(R10BIO_MadeGood, &r10_bio->state) \|\|
1838	test_bit(R10BIO_WriteError, &r10_bio->state))
1839	reschedule_retry(r10_bio);
1840	else
1841	put_buf(r10_bio);
1842	md_done_sync(mddev, s, 1);
1843	break;
1844	} else {
1845	struct r10bio r10_bio2 = (struct r10bio )r10_bio->master_bio;
1846	if (test_bit(R10BIO_MadeGood, &r10_bio->state) \|\|
1847	test_bit(R10BIO_WriteError, &r10_bio->state))
1848	reschedule_retry(r10_bio);
1849	else
1850	put_buf(r10_bio);
1851	r10_bio = r10_bio2;
1852	}
1853	}
1854	}
1855
1856	static void end_sync_write(struct bio *bio, int error)
1857	{
1858	int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
1859	struct r10bio *r10_bio = bio->bi_private;
1860	struct mddev *mddev = r10_bio->mddev;
1861	struct r10conf *conf = mddev->private;
1862	int d;
1863	sector_t first_bad;
1864	int bad_sectors;
1865	int slot;
1866	int repl;
1867	struct md_rdev *rdev = NULL;
1868
1869	d = find_bio_disk(conf, r10_bio, bio, &slot, &repl);
1870	if (repl)
1871	rdev = conf->mirrors[d].replacement;
1872	else
1873	rdev = conf->mirrors[d].rdev;
1874
1875	if (!uptodate) {
1876	if (repl)
1877	md_error(mddev, rdev);
1878	else {
1879	set_bit(WriteErrorSeen, &rdev->flags);
1880	if (!test_and_set_bit(WantReplacement, &rdev->flags))
1881	set_bit(MD_RECOVERY_NEEDED,
1882	&rdev->mddev->recovery);
1883	set_bit(R10BIO_WriteError, &r10_bio->state);
1884	}
1885	} else if (is_badblock(rdev,
1886	r10_bio->devs[slot].addr,
1887	r10_bio->sectors,
1888	&first_bad, &bad_sectors))
1889	set_bit(R10BIO_MadeGood, &r10_bio->state);
1890
1891	rdev_dec_pending(rdev, mddev);
1892
1893	end_sync_request(r10_bio);
1894	}
1895
1896	/*
1897	* Note: sync and recover and handled very differently for raid10
1898	* This code is for resync.
1899	* For resync, we read through virtual addresses and read all blocks.
1900	* If there is any error, we schedule a write. The lowest numbered
1901	* drive is authoritative.
1902	* However requests come for physical address, so we need to map.
1903	* For every physical address there are raid_disks/copies virtual addresses,
1904	* which is always are least one, but is not necessarly an integer.
1905	* This means that a physical address can span multiple chunks, so we may
1906	* have to submit multiple io requests for a single sync request.
1907	*/
1908	/*
1909	* We check if all blocks are in-sync and only write to blocks that
1910	* aren't in sync
1911	*/
1912	static void sync_request_write(struct mddev mddev, struct r10bio r10_bio)
1913	{
1914	struct r10conf *conf = mddev->private;
1915	int i, first;
1916	struct bio tbio, fbio;
1917	int vcnt;
1918
1919	atomic_set(&r10_bio->remaining, 1);
1920
1921	/* find the first device with a block */
1922	for (i=0; i<conf->copies; i++)
1923	if (test_bit(BIO_UPTODATE, &r10_bio->devs[i].bio->bi_flags))
1924	break;
1925
1926	if (i == conf->copies)
1927	goto done;
1928
1929	first = i;
1930	fbio = r10_bio->devs[i].bio;
1931
1932	vcnt = (r10_bio->sectors + (PAGE_SIZE >> 9) - 1) >> (PAGE_SHIFT - 9);
1933	/* now find blocks with errors */
1934	for (i=0 ; i < conf->copies ; i++) {
1935	int j, d;
1936
1937	tbio = r10_bio->devs[i].bio;
1938
1939	if (tbio->bi_end_io != end_sync_read)
1940	continue;
1941	if (i == first)
1942	continue;
1943	if (test_bit(BIO_UPTODATE, &r10_bio->devs[i].bio->bi_flags)) {
1944	/* We know that the bi_io_vec layout is the same for
1945	* both 'first' and 'i', so we just compare them.
1946	* All vec entries are PAGE_SIZE;
1947	*/
1948	for (j = 0; j < vcnt; j++)
1949	if (memcmp(page_address(fbio->bi_io_vec[j].bv_page),
1950	page_address(tbio->bi_io_vec[j].bv_page),
1951	fbio->bi_io_vec[j].bv_len))
1952	break;
1953	if (j == vcnt)
1954	continue;
1955	mddev->resync_mismatches += r10_bio->sectors;
1956	if (test_bit(MD_RECOVERY_CHECK, &mddev->recovery))
1957	/* Don't fix anything. */
1958	continue;
1959	}
1960	/* Ok, we need to write this bio, either to correct an
1961	* inconsistency or to correct an unreadable block.
1962	* First we need to fixup bv_offset, bv_len and
1963	* bi_vecs, as the read request might have corrupted these
1964	*/
1965	tbio->bi_vcnt = vcnt;
1966	tbio->bi_size = r10_bio->sectors << 9;
1967	tbio->bi_idx = 0;
1968	tbio->bi_phys_segments = 0;
1969	tbio->bi_flags &= ~(BIO_POOL_MASK - 1);
1970	tbio->bi_flags \|= 1 << BIO_UPTODATE;
1971	tbio->bi_next = NULL;
1972	tbio->bi_rw = WRITE;
1973	tbio->bi_private = r10_bio;
1974	tbio->bi_sector = r10_bio->devs[i].addr;
1975
1976	for (j=0; j < vcnt ; j++) {
1977	tbio->bi_io_vec[j].bv_offset = 0;
1978	tbio->bi_io_vec[j].bv_len = PAGE_SIZE;
1979
1980	memcpy(page_address(tbio->bi_io_vec[j].bv_page),
1981	page_address(fbio->bi_io_vec[j].bv_page),
1982	PAGE_SIZE);
1983	}
1984	tbio->bi_end_io = end_sync_write;
1985
1986	d = r10_bio->devs[i].devnum;
1987	atomic_inc(&conf->mirrors[d].rdev->nr_pending);
1988	atomic_inc(&r10_bio->remaining);
1989	md_sync_acct(conf->mirrors[d].rdev->bdev, tbio->bi_size >> 9);
1990
1991	tbio->bi_sector += conf->mirrors[d].rdev->data_offset;
1992	tbio->bi_bdev = conf->mirrors[d].rdev->bdev;
1993	generic_make_request(tbio);
1994	}
1995
1996	/* Now write out to any replacement devices
1997	* that are active
1998	*/
1999	for (i = 0; i < conf->copies; i++) {
2000	int j, d;
2001
2002	tbio = r10_bio->devs[i].repl_bio;
2003	if (!tbio \|\| !tbio->bi_end_io)
2004	continue;
2005	if (r10_bio->devs[i].bio->bi_end_io != end_sync_write
2006	&& r10_bio->devs[i].bio != fbio)
2007	for (j = 0; j < vcnt; j++)
2008	memcpy(page_address(tbio->bi_io_vec[j].bv_page),
2009	page_address(fbio->bi_io_vec[j].bv_page),
2010	PAGE_SIZE);
2011	d = r10_bio->devs[i].devnum;
2012	atomic_inc(&r10_bio->remaining);
2013	md_sync_acct(conf->mirrors[d].replacement->bdev,
2014	tbio->bi_size >> 9);
2015	generic_make_request(tbio);
2016	}
2017
2018	done:
2019	if (atomic_dec_and_test(&r10_bio->remaining)) {
2020	md_done_sync(mddev, r10_bio->sectors, 1);
2021	put_buf(r10_bio);
2022	}
2023	}
2024
2025	/*
2026	* Now for the recovery code.
2027	* Recovery happens across physical sectors.
2028	* We recover all non-is_sync drives by finding the virtual address of
2029	* each, and then choose a working drive that also has that virt address.
2030	* There is a separate r10_bio for each non-in_sync drive.
2031	* Only the first two slots are in use. The first for reading,
2032	* The second for writing.
2033	*
2034	*/
2035	static void fix_recovery_read_error(struct r10bio *r10_bio)
2036	{
2037	/* We got a read error during recovery.
2038	* We repeat the read in smaller page-sized sections.
2039	* If a read succeeds, write it to the new device or record
2040	* a bad block if we cannot.
2041	* If a read fails, record a bad block on both old and
2042	* new devices.
2043	*/
2044	struct mddev *mddev = r10_bio->mddev;
2045	struct r10conf *conf = mddev->private;
2046	struct bio *bio = r10_bio->devs[0].bio;
2047	sector_t sect = 0;
2048	int sectors = r10_bio->sectors;
2049	int idx = 0;
2050	int dr = r10_bio->devs[0].devnum;
2051	int dw = r10_bio->devs[1].devnum;
2052
2053	while (sectors) {
2054	int s = sectors;
2055	struct md_rdev *rdev;
2056	sector_t addr;
2057	int ok;
2058
2059	if (s > (PAGE_SIZE>>9))
2060	s = PAGE_SIZE >> 9;
2061
2062	rdev = conf->mirrors[dr].rdev;
2063	addr = r10_bio->devs[0].addr + sect,
2064	ok = sync_page_io(rdev,
2065	addr,
2066	s << 9,
2067	bio->bi_io_vec[idx].bv_page,
2068	READ, false);
2069	if (ok) {
2070	rdev = conf->mirrors[dw].rdev;
2071	addr = r10_bio->devs[1].addr + sect;
2072	ok = sync_page_io(rdev,
2073	addr,
2074	s << 9,
2075	bio->bi_io_vec[idx].bv_page,
2076	WRITE, false);
2077	if (!ok) {
2078	set_bit(WriteErrorSeen, &rdev->flags);
2079	if (!test_and_set_bit(WantReplacement,
2080	&rdev->flags))
2081	set_bit(MD_RECOVERY_NEEDED,
2082	&rdev->mddev->recovery);
2083	}
2084	}
2085	if (!ok) {
2086	/* We don't worry if we cannot set a bad block -
2087	* it really is bad so there is no loss in not
2088	* recording it yet
2089	*/
2090	rdev_set_badblocks(rdev, addr, s, 0);
2091
2092	if (rdev != conf->mirrors[dw].rdev) {
2093	/* need bad block on destination too */
2094	struct md_rdev *rdev2 = conf->mirrors[dw].rdev;
2095	addr = r10_bio->devs[1].addr + sect;
2096	ok = rdev_set_badblocks(rdev2, addr, s, 0);
2097	if (!ok) {
2098	/* just abort the recovery */
2099	printk(KERN_NOTICE
2100	"md/raid10:%s: recovery aborted"
2101	" due to read error\n",
2102	mdname(mddev));
2103
2104	conf->mirrors[dw].recovery_disabled
2105	= mddev->recovery_disabled;
2106	set_bit(MD_RECOVERY_INTR,
2107	&mddev->recovery);
2108	break;
2109	}
2110	}
2111	}
2112
2113	sectors -= s;
2114	sect += s;
2115	idx++;
2116	}
2117	}
2118
2119	static void recovery_request_write(struct mddev mddev, struct r10bio r10_bio)
2120	{
2121	struct r10conf *conf = mddev->private;
2122	int d;
2123	struct bio wbio, wbio2;
2124
2125	if (!test_bit(R10BIO_Uptodate, &r10_bio->state)) {
2126	fix_recovery_read_error(r10_bio);
2127	end_sync_request(r10_bio);
2128	return;
2129	}
2130
2131	/*
2132	* share the pages with the first bio
2133	* and submit the write request
2134	*/
2135	d = r10_bio->devs[1].devnum;
2136	wbio = r10_bio->devs[1].bio;
2137	wbio2 = r10_bio->devs[1].repl_bio;
2138	if (wbio->bi_end_io) {
2139	atomic_inc(&conf->mirrors[d].rdev->nr_pending);
2140	md_sync_acct(conf->mirrors[d].rdev->bdev, wbio->bi_size >> 9);
2141	generic_make_request(wbio);
2142	}
2143	if (wbio2 && wbio2->bi_end_io) {
2144	atomic_inc(&conf->mirrors[d].replacement->nr_pending);
2145	md_sync_acct(conf->mirrors[d].replacement->bdev,
2146	wbio2->bi_size >> 9);
2147	generic_make_request(wbio2);
2148	}
2149	}
2150
2151
2152	/*
2153	* Used by fix_read_error() to decay the per rdev read_errors.
2154	* We halve the read error count for every hour that has elapsed
2155	* since the last recorded read error.
2156	*
2157	*/
2158	static void check_decay_read_errors(struct mddev mddev, struct md_rdev rdev)
2159	{
2160	struct timespec cur_time_mon;
2161	unsigned long hours_since_last;
2162	unsigned int read_errors = atomic_read(&rdev->read_errors);
2163
2164	ktime_get_ts(&cur_time_mon);
2165
2166	if (rdev->last_read_error.tv_sec == 0 &&
2167	rdev->last_read_error.tv_nsec == 0) {
2168	/* first time we've seen a read error */
2169	rdev->last_read_error = cur_time_mon;
2170	return;
2171	}
2172
2173	hours_since_last = (cur_time_mon.tv_sec -
2174	rdev->last_read_error.tv_sec) / 3600;
2175
2176	rdev->last_read_error = cur_time_mon;
2177
2178	/*
2179	* if hours_since_last is > the number of bits in read_errors
2180	* just set read errors to 0. We do this to avoid
2181	* overflowing the shift of read_errors by hours_since_last.
2182	*/
2183	if (hours_since_last >= 8 * sizeof(read_errors))
2184	atomic_set(&rdev->read_errors, 0);
2185	else
2186	atomic_set(&rdev->read_errors, read_errors >> hours_since_last);
2187	}
2188
2189	static int r10_sync_page_io(struct md_rdev *rdev, sector_t sector,
2190	int sectors, struct page *page, int rw)
2191	{
2192	sector_t first_bad;
2193	int bad_sectors;
2194
2195	if (is_badblock(rdev, sector, sectors, &first_bad, &bad_sectors)
2196	&& (rw == READ \|\| test_bit(WriteErrorSeen, &rdev->flags)))
2197	return -1;
2198	if (sync_page_io(rdev, sector, sectors << 9, page, rw, false))
2199	/* success */
2200	return 1;
2201	if (rw == WRITE) {
2202	set_bit(WriteErrorSeen, &rdev->flags);
2203	if (!test_and_set_bit(WantReplacement, &rdev->flags))
2204	set_bit(MD_RECOVERY_NEEDED,
2205	&rdev->mddev->recovery);
2206	}
2207	/* need to record an error - either for the block or the device */
2208	if (!rdev_set_badblocks(rdev, sector, sectors, 0))
2209	md_error(rdev->mddev, rdev);
2210	return 0;
2211	}
2212
2213	/*
2214	* This is a kernel thread which:
2215	*
2216	* 1. Retries failed read operations on working mirrors.
2217	* 2. Updates the raid superblock when problems encounter.
2218	* 3. Performs writes following reads for array synchronising.
2219	*/
2220
2221	static void fix_read_error(struct r10conf conf, struct mddev mddev, struct r10bio *r10_bio)
2222	{
2223	int sect = 0; /* Offset from r10_bio->sector */
2224	int sectors = r10_bio->sectors;
2225	struct md_rdev*rdev;
2226	int max_read_errors = atomic_read(&mddev->max_corr_read_errors);
2227	int d = r10_bio->devs[r10_bio->read_slot].devnum;
2228
2229	/* still own a reference to this rdev, so it cannot
2230	* have been cleared recently.
2231	*/
2232	rdev = conf->mirrors[d].rdev;
2233
2234	if (test_bit(Faulty, &rdev->flags))
2235	/* drive has already been failed, just ignore any
2236	more fix_read_error() attempts */
2237	return;
2238
2239	check_decay_read_errors(mddev, rdev);
2240	atomic_inc(&rdev->read_errors);
2241	if (atomic_read(&rdev->read_errors) > max_read_errors) {
2242	char b[BDEVNAME_SIZE];
2243	bdevname(rdev->bdev, b);
2244
2245	printk(KERN_NOTICE
2246	"md/raid10:%s: %s: Raid device exceeded "
2247	"read_error threshold [cur %d:max %d]\n",
2248	mdname(mddev), b,
2249	atomic_read(&rdev->read_errors), max_read_errors);
2250	printk(KERN_NOTICE
2251	"md/raid10:%s: %s: Failing raid device\n",
2252	mdname(mddev), b);
2253	md_error(mddev, conf->mirrors[d].rdev);
2254	r10_bio->devs[r10_bio->read_slot].bio = IO_BLOCKED;
2255	return;
2256	}
2257
2258	while(sectors) {
2259	int s = sectors;
2260	int sl = r10_bio->read_slot;
2261	int success = 0;
2262	int start;
2263
2264	if (s > (PAGE_SIZE>>9))
2265	s = PAGE_SIZE >> 9;
2266
2267	rcu_read_lock();
2268	do {
2269	sector_t first_bad;
2270	int bad_sectors;
2271
2272	d = r10_bio->devs[sl].devnum;
2273	rdev = rcu_dereference(conf->mirrors[d].rdev);
2274	if (rdev &&
2275	!test_bit(Unmerged, &rdev->flags) &&
2276	test_bit(In_sync, &rdev->flags) &&
2277	is_badblock(rdev, r10_bio->devs[sl].addr + sect, s,
2278	&first_bad, &bad_sectors) == 0) {
2279	atomic_inc(&rdev->nr_pending);
2280	rcu_read_unlock();
2281	success = sync_page_io(rdev,
2282	r10_bio->devs[sl].addr +
2283	sect,
2284	s<<9,
2285	conf->tmppage, READ, false);
2286	rdev_dec_pending(rdev, mddev);
2287	rcu_read_lock();
2288	if (success)
2289	break;
2290	}
2291	sl++;
2292	if (sl == conf->copies)
2293	sl = 0;
2294	} while (!success && sl != r10_bio->read_slot);
2295	rcu_read_unlock();
2296
2297	if (!success) {
2298	/* Cannot read from anywhere, just mark the block
2299	* as bad on the first device to discourage future
2300	* reads.
2301	*/
2302	int dn = r10_bio->devs[r10_bio->read_slot].devnum;
2303	rdev = conf->mirrors[dn].rdev;
2304
2305	if (!rdev_set_badblocks(
2306	rdev,
2307	r10_bio->devs[r10_bio->read_slot].addr
2308	+ sect,
2309	s, 0)) {
2310	md_error(mddev, rdev);
2311	r10_bio->devs[r10_bio->read_slot].bio
2312	= IO_BLOCKED;
2313	}
2314	break;
2315	}
2316
2317	start = sl;
2318	/* write it back and re-read */
2319	rcu_read_lock();
2320	while (sl != r10_bio->read_slot) {
2321	char b[BDEVNAME_SIZE];
2322
2323	if (sl==0)
2324	sl = conf->copies;
2325	sl--;
2326	d = r10_bio->devs[sl].devnum;
2327	rdev = rcu_dereference(conf->mirrors[d].rdev);
2328	if (!rdev \|\|
2329	test_bit(Unmerged, &rdev->flags) \|\|
2330	!test_bit(In_sync, &rdev->flags))
2331	continue;
2332
2333	atomic_inc(&rdev->nr_pending);
2334	rcu_read_unlock();
2335	if (r10_sync_page_io(rdev,
2336	r10_bio->devs[sl].addr +
2337	sect,
2338	s, conf->tmppage, WRITE)
2339	== 0) {
2340	/* Well, this device is dead */
2341	printk(KERN_NOTICE
2342	"md/raid10:%s: read correction "
2343	"write failed"
2344	" (%d sectors at %llu on %s)\n",
2345	mdname(mddev), s,
2346	(unsigned long long)(
2347	sect +
2348	choose_data_offset(r10_bio,
2349	rdev)),
2350	bdevname(rdev->bdev, b));
2351	printk(KERN_NOTICE "md/raid10:%s: %s: failing "
2352	"drive\n",
2353	mdname(mddev),
2354	bdevname(rdev->bdev, b));
2355	}
2356	rdev_dec_pending(rdev, mddev);
2357	rcu_read_lock();
2358	}
2359	sl = start;
2360	while (sl != r10_bio->read_slot) {
2361	char b[BDEVNAME_SIZE];
2362
2363	if (sl==0)
2364	sl = conf->copies;
2365	sl--;
2366	d = r10_bio->devs[sl].devnum;
2367	rdev = rcu_dereference(conf->mirrors[d].rdev);
2368	if (!rdev \|\|
2369	!test_bit(In_sync, &rdev->flags))
2370	continue;
2371
2372	atomic_inc(&rdev->nr_pending);
2373	rcu_read_unlock();
2374	switch (r10_sync_page_io(rdev,
2375	r10_bio->devs[sl].addr +
2376	sect,
2377	s, conf->tmppage,
2378	READ)) {
2379	case 0:
2380	/* Well, this device is dead */
2381	printk(KERN_NOTICE
2382	"md/raid10:%s: unable to read back "
2383	"corrected sectors"
2384	" (%d sectors at %llu on %s)\n",
2385	mdname(mddev), s,
2386	(unsigned long long)(
2387	sect +
2388	choose_data_offset(r10_bio, rdev)),
2389	bdevname(rdev->bdev, b));
2390	printk(KERN_NOTICE "md/raid10:%s: %s: failing "
2391	"drive\n",
2392	mdname(mddev),
2393	bdevname(rdev->bdev, b));
2394	break;
2395	case 1:
2396	printk(KERN_INFO
2397	"md/raid10:%s: read error corrected"
2398	" (%d sectors at %llu on %s)\n",
2399	mdname(mddev), s,
2400	(unsigned long long)(
2401	sect +
2402	choose_data_offset(r10_bio, rdev)),
2403	bdevname(rdev->bdev, b));
2404	atomic_add(s, &rdev->corrected_errors);
2405	}
2406
2407	rdev_dec_pending(rdev, mddev);
2408	rcu_read_lock();
2409	}
2410	rcu_read_unlock();
2411
2412	sectors -= s;
2413	sect += s;
2414	}
2415	}
2416
2417	static void bi_complete(struct bio *bio, int error)
2418	{
2419	complete((struct completion *)bio->bi_private);
2420	}
2421
2422	static int submit_bio_wait(int rw, struct bio *bio)
2423	{
2424	struct completion event;
2425	rw \|= REQ_SYNC;
2426
2427	init_completion(&event);
2428	bio->bi_private = &event;
2429	bio->bi_end_io = bi_complete;
2430	submit_bio(rw, bio);
2431	wait_for_completion(&event);
2432
2433	return test_bit(BIO_UPTODATE, &bio->bi_flags);
2434	}
2435
2436	static int narrow_write_error(struct r10bio *r10_bio, int i)
2437	{
2438	struct bio *bio = r10_bio->master_bio;
2439	struct mddev *mddev = r10_bio->mddev;
2440	struct r10conf *conf = mddev->private;
2441	struct md_rdev *rdev = conf->mirrors[r10_bio->devs[i].devnum].rdev;
2442	/* bio has the data to be written to slot 'i' where
2443	* we just recently had a write error.
2444	* We repeatedly clone the bio and trim down to one block,
2445	* then try the write. Where the write fails we record
2446	* a bad block.
2447	* It is conceivable that the bio doesn't exactly align with
2448	* blocks. We must handle this.
2449	*
2450	* We currently own a reference to the rdev.
2451	*/
2452
2453	int block_sectors;
2454	sector_t sector;
2455	int sectors;
2456	int sect_to_write = r10_bio->sectors;
2457	int ok = 1;
2458
2459	if (rdev->badblocks.shift < 0)
2460	return 0;
2461
2462	block_sectors = 1 << rdev->badblocks.shift;
2463	sector = r10_bio->sector;
2464	sectors = ((r10_bio->sector + block_sectors)
2465	& ~(sector_t)(block_sectors - 1))
2466	- sector;
2467
2468	while (sect_to_write) {
2469	struct bio *wbio;
2470	if (sectors > sect_to_write)
2471	sectors = sect_to_write;
2472	/* Write at 'sector' for 'sectors' */
2473	wbio = bio_clone_mddev(bio, GFP_NOIO, mddev);
2474	md_trim_bio(wbio, sector - bio->bi_sector, sectors);
2475	wbio->bi_sector = (r10_bio->devs[i].addr+
2476	choose_data_offset(r10_bio, rdev) +
2477	(sector - r10_bio->sector));
2478	wbio->bi_bdev = rdev->bdev;
2479	if (submit_bio_wait(WRITE, wbio) == 0)
2480	/* Failure! */
2481	ok = rdev_set_badblocks(rdev, sector,
2482	sectors, 0)
2483	&& ok;
2484
2485	bio_put(wbio);
2486	sect_to_write -= sectors;
2487	sector += sectors;
2488	sectors = block_sectors;
2489	}
2490	return ok;
2491	}
2492
2493	static void handle_read_error(struct mddev mddev, struct r10bio r10_bio)
2494	{
2495	int slot = r10_bio->read_slot;
2496	struct bio *bio;
2497	struct r10conf *conf = mddev->private;
2498	struct md_rdev *rdev = r10_bio->devs[slot].rdev;
2499	char b[BDEVNAME_SIZE];
2500	unsigned long do_sync;
2501	int max_sectors;
2502
2503	/* we got a read error. Maybe the drive is bad. Maybe just
2504	* the block and we can fix it.
2505	* We freeze all other IO, and try reading the block from
2506	* other devices. When we find one, we re-write
2507	* and check it that fixes the read error.
2508	* This is all done synchronously while the array is
2509	* frozen.
2510	*/
2511	bio = r10_bio->devs[slot].bio;
2512	bdevname(bio->bi_bdev, b);
2513	bio_put(bio);
2514	r10_bio->devs[slot].bio = NULL;
2515
2516	if (mddev->ro == 0) {
2517	freeze_array(conf);
2518	fix_read_error(conf, mddev, r10_bio);
2519	unfreeze_array(conf);
2520	} else
2521	r10_bio->devs[slot].bio = IO_BLOCKED;
2522
2523	rdev_dec_pending(rdev, mddev);
2524
2525	read_more:
2526	rdev = read_balance(conf, r10_bio, &max_sectors);
2527	if (rdev == NULL) {
2528	printk(KERN_ALERT "md/raid10:%s: %s: unrecoverable I/O"
2529	" read error for block %llu\n",
2530	mdname(mddev), b,
2531	(unsigned long long)r10_bio->sector);
2532	raid_end_bio_io(r10_bio);
2533	return;
2534	}
2535
2536	do_sync = (r10_bio->master_bio->bi_rw & REQ_SYNC);
2537	slot = r10_bio->read_slot;
2538	printk_ratelimited(
2539	KERN_ERR
2540	"md/raid10:%s: %s: redirecting "
2541	"sector %llu to another mirror\n",
2542	mdname(mddev),
2543	bdevname(rdev->bdev, b),
2544	(unsigned long long)r10_bio->sector);
2545	bio = bio_clone_mddev(r10_bio->master_bio,
2546	GFP_NOIO, mddev);
2547	md_trim_bio(bio,
2548	r10_bio->sector - bio->bi_sector,
2549	max_sectors);
2550	r10_bio->devs[slot].bio = bio;
2551	r10_bio->devs[slot].rdev = rdev;
2552	bio->bi_sector = r10_bio->devs[slot].addr
2553	+ choose_data_offset(r10_bio, rdev);
2554	bio->bi_bdev = rdev->bdev;
2555	bio->bi_rw = READ \| do_sync;
2556	bio->bi_private = r10_bio;
2557	bio->bi_end_io = raid10_end_read_request;
2558	if (max_sectors < r10_bio->sectors) {
2559	/* Drat - have to split this up more */
2560	struct bio *mbio = r10_bio->master_bio;
2561	int sectors_handled =
2562	r10_bio->sector + max_sectors
2563	- mbio->bi_sector;
2564	r10_bio->sectors = max_sectors;
2565	spin_lock_irq(&conf->device_lock);
2566	if (mbio->bi_phys_segments == 0)
2567	mbio->bi_phys_segments = 2;
2568	else
2569	mbio->bi_phys_segments++;
2570	spin_unlock_irq(&conf->device_lock);
2571	generic_make_request(bio);
2572
2573	r10_bio = mempool_alloc(conf->r10bio_pool,
2574	GFP_NOIO);
2575	r10_bio->master_bio = mbio;
2576	r10_bio->sectors = (mbio->bi_size >> 9)
2577	- sectors_handled;
2578	r10_bio->state = 0;
2579	set_bit(R10BIO_ReadError,
2580	&r10_bio->state);
2581	r10_bio->mddev = mddev;
2582	r10_bio->sector = mbio->bi_sector
2583	+ sectors_handled;
2584
2585	goto read_more;
2586	} else
2587	generic_make_request(bio);
2588	}
2589
2590	static void handle_write_completed(struct r10conf conf, struct r10bio r10_bio)
2591	{
2592	/* Some sort of write request has finished and it
2593	* succeeded in writing where we thought there was a
2594	* bad block. So forget the bad block.
2595	* Or possibly if failed and we need to record
2596	* a bad block.
2597	*/
2598	int m;
2599	struct md_rdev *rdev;
2600
2601	if (test_bit(R10BIO_IsSync, &r10_bio->state) \|\|
2602	test_bit(R10BIO_IsRecover, &r10_bio->state)) {
2603	for (m = 0; m < conf->copies; m++) {
2604	int dev = r10_bio->devs[m].devnum;
2605	rdev = conf->mirrors[dev].rdev;
2606	if (r10_bio->devs[m].bio == NULL)
2607	continue;
2608	if (test_bit(BIO_UPTODATE,
2609	&r10_bio->devs[m].bio->bi_flags)) {
2610	rdev_clear_badblocks(
2611	rdev,
2612	r10_bio->devs[m].addr,
2613	r10_bio->sectors, 0);
2614	} else {
2615	if (!rdev_set_badblocks(
2616	rdev,
2617	r10_bio->devs[m].addr,
2618	r10_bio->sectors, 0))
2619	md_error(conf->mddev, rdev);
2620	}
2621	rdev = conf->mirrors[dev].replacement;
2622	if (r10_bio->devs[m].repl_bio == NULL)
2623	continue;
2624	if (test_bit(BIO_UPTODATE,
2625	&r10_bio->devs[m].repl_bio->bi_flags)) {
2626	rdev_clear_badblocks(
2627	rdev,
2628	r10_bio->devs[m].addr,
2629	r10_bio->sectors, 0);
2630	} else {
2631	if (!rdev_set_badblocks(
2632	rdev,
2633	r10_bio->devs[m].addr,
2634	r10_bio->sectors, 0))
2635	md_error(conf->mddev, rdev);
2636	}
2637	}
2638	put_buf(r10_bio);
2639	} else {
2640	for (m = 0; m < conf->copies; m++) {
2641	int dev = r10_bio->devs[m].devnum;
2642	struct bio *bio = r10_bio->devs[m].bio;
2643	rdev = conf->mirrors[dev].rdev;
2644	if (bio == IO_MADE_GOOD) {
2645	rdev_clear_badblocks(
2646	rdev,
2647	r10_bio->devs[m].addr,
2648	r10_bio->sectors, 0);
2649	rdev_dec_pending(rdev, conf->mddev);
2650	} else if (bio != NULL &&
2651	!test_bit(BIO_UPTODATE, &bio->bi_flags)) {
2652	if (!narrow_write_error(r10_bio, m)) {
2653	md_error(conf->mddev, rdev);
2654	set_bit(R10BIO_Degraded,
2655	&r10_bio->state);
2656	}
2657	rdev_dec_pending(rdev, conf->mddev);
2658	}
2659	bio = r10_bio->devs[m].repl_bio;
2660	rdev = conf->mirrors[dev].replacement;
2661	if (rdev && bio == IO_MADE_GOOD) {
2662	rdev_clear_badblocks(
2663	rdev,
2664	r10_bio->devs[m].addr,
2665	r10_bio->sectors, 0);
2666	rdev_dec_pending(rdev, conf->mddev);
2667	}
2668	}
2669	if (test_bit(R10BIO_WriteError,
2670	&r10_bio->state))
2671	close_write(r10_bio);
2672	raid_end_bio_io(r10_bio);
2673	}
2674	}
2675
2676	static void raid10d(struct mddev *mddev)
2677	{
2678	struct r10bio *r10_bio;
2679	unsigned long flags;
2680	struct r10conf *conf = mddev->private;
2681	struct list_head *head = &conf->retry_list;
2682	struct blk_plug plug;
2683
2684	md_check_recovery(mddev);
2685
2686	blk_start_plug(&plug);
2687	for (;;) {
2688
2689	flush_pending_writes(conf);
2690
2691	spin_lock_irqsave(&conf->device_lock, flags);
2692	if (list_empty(head)) {
2693	spin_unlock_irqrestore(&conf->device_lock, flags);
2694	break;
2695	}
2696	r10_bio = list_entry(head->prev, struct r10bio, retry_list);
2697	list_del(head->prev);
2698	conf->nr_queued--;
2699	spin_unlock_irqrestore(&conf->device_lock, flags);
2700
2701	mddev = r10_bio->mddev;
2702	conf = mddev->private;
2703	if (test_bit(R10BIO_MadeGood, &r10_bio->state) \|\|
2704	test_bit(R10BIO_WriteError, &r10_bio->state))
2705	handle_write_completed(conf, r10_bio);
2706	else if (test_bit(R10BIO_IsReshape, &r10_bio->state))
2707	reshape_request_write(mddev, r10_bio);
2708	else if (test_bit(R10BIO_IsSync, &r10_bio->state))
2709	sync_request_write(mddev, r10_bio);
2710	else if (test_bit(R10BIO_IsRecover, &r10_bio->state))
2711	recovery_request_write(mddev, r10_bio);
2712	else if (test_bit(R10BIO_ReadError, &r10_bio->state))
2713	handle_read_error(mddev, r10_bio);
2714	else {
2715	/* just a partial read to be scheduled from a
2716	* separate context
2717	*/
2718	int slot = r10_bio->read_slot;
2719	generic_make_request(r10_bio->devs[slot].bio);
2720	}
2721
2722	cond_resched();
2723	if (mddev->flags & ~(1<<MD_CHANGE_PENDING))
2724	md_check_recovery(mddev);
2725	}
2726	blk_finish_plug(&plug);
2727	}
2728
2729
2730	static int init_resync(struct r10conf *conf)
2731	{
2732	int buffs;
2733	int i;
2734
2735	buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE;
2736	BUG_ON(conf->r10buf_pool);
2737	conf->have_replacement = 0;
2738	for (i = 0; i < conf->geo.raid_disks; i++)
2739	if (conf->mirrors[i].replacement)
2740	conf->have_replacement = 1;
2741	conf->r10buf_pool = mempool_create(buffs, r10buf_pool_alloc, r10buf_pool_free, conf);
2742	if (!conf->r10buf_pool)
2743	return -ENOMEM;
2744	conf->next_resync = 0;
2745	return 0;
2746	}
2747
2748	/*
2749	* perform a "sync" on one "block"
2750	*
2751	* We need to make sure that no normal I/O request - particularly write
2752	* requests - conflict with active sync requests.
2753	*
2754	* This is achieved by tracking pending requests and a 'barrier' concept
2755	* that can be installed to exclude normal IO requests.
2756	*
2757	* Resync and recovery are handled very differently.
2758	* We differentiate by looking at MD_RECOVERY_SYNC in mddev->recovery.
2759	*
2760	* For resync, we iterate over virtual addresses, read all copies,
2761	* and update if there are differences. If only one copy is live,
2762	* skip it.
2763	* For recovery, we iterate over physical addresses, read a good
2764	* value for each non-in_sync drive, and over-write.
2765	*
2766	* So, for recovery we may have several outstanding complex requests for a
2767	* given address, one for each out-of-sync device. We model this by allocating
2768	* a number of r10_bio structures, one for each out-of-sync device.
2769	* As we setup these structures, we collect all bio's together into a list
2770	* which we then process collectively to add pages, and then process again
2771	* to pass to generic_make_request.
2772	*
2773	* The r10_bio structures are linked using a borrowed master_bio pointer.
2774	* This link is counted in ->remaining. When the r10_bio that points to NULL
2775	* has its remaining count decremented to 0, the whole complex operation
2776	* is complete.
2777	*
2778	*/
2779
2780	static sector_t sync_request(struct mddev *mddev, sector_t sector_nr,
2781	int *skipped, int go_faster)
2782	{
2783	struct r10conf *conf = mddev->private;
2784	struct r10bio *r10_bio;
2785	struct bio biolist = NULL, bio;
2786	sector_t max_sector, nr_sectors;
2787	int i;
2788	int max_sync;
2789	sector_t sync_blocks;
2790	sector_t sectors_skipped = 0;
2791	int chunks_skipped = 0;
2792	sector_t chunk_mask = conf->geo.chunk_mask;
2793
2794	if (!conf->r10buf_pool)
2795	if (init_resync(conf))
2796	return 0;
2797
2798	skipped:
2799	max_sector = mddev->dev_sectors;
2800	if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) \|\|
2801	test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
2802	max_sector = mddev->resync_max_sectors;
2803	if (sector_nr >= max_sector) {
2804	/* If we aborted, we need to abort the
2805	* sync on the 'current' bitmap chucks (there can
2806	* be several when recovering multiple devices).
2807	* as we may have started syncing it but not finished.
2808	* We can find the current address in
2809	* mddev->curr_resync, but for recovery,
2810	* we need to convert that to several
2811	* virtual addresses.
2812	*/
2813	if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) {
2814	end_reshape(conf);
2815	return 0;
2816	}
2817
2818	if (mddev->curr_resync < max_sector) { /* aborted */
2819	if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery))
2820	bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
2821	&sync_blocks, 1);
2822	else for (i = 0; i < conf->geo.raid_disks; i++) {
2823	sector_t sect =
2824	raid10_find_virt(conf, mddev->curr_resync, i);
2825	bitmap_end_sync(mddev->bitmap, sect,
2826	&sync_blocks, 1);
2827	}
2828	} else {
2829	/* completed sync */
2830	if ((!mddev->bitmap \|\| conf->fullsync)
2831	&& conf->have_replacement
2832	&& test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
2833	/* Completed a full sync so the replacements
2834	* are now fully recovered.
2835	*/
2836	for (i = 0; i < conf->geo.raid_disks; i++)
2837	if (conf->mirrors[i].replacement)
2838	conf->mirrors[i].replacement
2839	->recovery_offset
2840	= MaxSector;
2841	}
2842	conf->fullsync = 0;
2843	}
2844	bitmap_close_sync(mddev->bitmap);
2845	close_sync(conf);
2846	*skipped = 1;
2847	return sectors_skipped;
2848	}
2849
2850	if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
2851	return reshape_request(mddev, sector_nr, skipped);
2852
2853	if (chunks_skipped >= conf->geo.raid_disks) {
2854	/* if there has been nothing to do on any drive,
2855	* then there is nothing to do at all..
2856	*/
2857	*skipped = 1;
2858	return (max_sector - sector_nr) + sectors_skipped;
2859	}
2860
2861	if (max_sector > mddev->resync_max)
2862	max_sector = mddev->resync_max; /* Don't do IO beyond here */
2863
2864	/* make sure whole request will fit in a chunk - if chunks
2865	* are meaningful
2866	*/
2867	if (conf->geo.near_copies < conf->geo.raid_disks &&
2868	max_sector > (sector_nr \| chunk_mask))
2869	max_sector = (sector_nr \| chunk_mask) + 1;
2870	/*
2871	* If there is non-resync activity waiting for us then
2872	* put in a delay to throttle resync.
2873	*/
2874	if (!go_faster && conf->nr_waiting)
2875	msleep_interruptible(1000);
2876
2877	/* Again, very different code for resync and recovery.
2878	* Both must result in an r10bio with a list of bios that
2879	* have bi_end_io, bi_sector, bi_bdev set,
2880	* and bi_private set to the r10bio.
2881	* For recovery, we may actually create several r10bios
2882	* with 2 bios in each, that correspond to the bios in the main one.
2883	* In this case, the subordinate r10bios link back through a
2884	* borrowed master_bio pointer, and the counter in the master
2885	* includes a ref from each subordinate.
2886	*/
2887	/* First, we decide what to do and set ->bi_end_io
2888	* To end_sync_read if we want to read, and
2889	* end_sync_write if we will want to write.
2890	*/
2891
2892	max_sync = RESYNC_PAGES << (PAGE_SHIFT-9);
2893	if (!test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
2894	/* recovery... the complicated one */
2895	int j;
2896	r10_bio = NULL;
2897
2898	for (i = 0 ; i < conf->geo.raid_disks; i++) {
2899	int still_degraded;
2900	struct r10bio *rb2;
2901	sector_t sect;
2902	int must_sync;
2903	int any_working;
2904	struct raid10_info *mirror = &conf->mirrors[i];
2905
2906	if ((mirror->rdev == NULL \|\|
2907	test_bit(In_sync, &mirror->rdev->flags))
2908	&&
2909	(mirror->replacement == NULL \|\|
2910	test_bit(Faulty,
2911	&mirror->replacement->flags)))
2912	continue;
2913
2914	still_degraded = 0;
2915	/* want to reconstruct this device */
2916	rb2 = r10_bio;
2917	sect = raid10_find_virt(conf, sector_nr, i);
2918	if (sect >= mddev->resync_max_sectors) {
2919	/* last stripe is not complete - don't
2920	* try to recover this sector.
2921	*/
2922	continue;
2923	}
2924	/* Unless we are doing a full sync, or a replacement
2925	* we only need to recover the block if it is set in
2926	* the bitmap
2927	*/
2928	must_sync = bitmap_start_sync(mddev->bitmap, sect,
2929	&sync_blocks, 1);
2930	if (sync_blocks < max_sync)
2931	max_sync = sync_blocks;
2932	if (!must_sync &&
2933	mirror->replacement == NULL &&
2934	!conf->fullsync) {
2935	/* yep, skip the sync_blocks here, but don't assume
2936	* that there will never be anything to do here
2937	*/
2938	chunks_skipped = -1;
2939	continue;
2940	}
2941
2942	r10_bio = mempool_alloc(conf->r10buf_pool, GFP_NOIO);
2943	raise_barrier(conf, rb2 != NULL);
2944	atomic_set(&r10_bio->remaining, 0);
2945
2946	r10_bio->master_bio = (struct bio*)rb2;
2947	if (rb2)
2948	atomic_inc(&rb2->remaining);
2949	r10_bio->mddev = mddev;
2950	set_bit(R10BIO_IsRecover, &r10_bio->state);
2951	r10_bio->sector = sect;
2952
2953	raid10_find_phys(conf, r10_bio);
2954
2955	/* Need to check if the array will still be
2956	* degraded
2957	*/
2958	for (j = 0; j < conf->geo.raid_disks; j++)
2959	if (conf->mirrors[j].rdev == NULL \|\|
2960	test_bit(Faulty, &conf->mirrors[j].rdev->flags)) {
2961	still_degraded = 1;
2962	break;
2963	}
2964
2965	must_sync = bitmap_start_sync(mddev->bitmap, sect,
2966	&sync_blocks, still_degraded);
2967
2968	any_working = 0;
2969	for (j=0; j<conf->copies;j++) {
2970	int k;
2971	int d = r10_bio->devs[j].devnum;
2972	sector_t from_addr, to_addr;
2973	struct md_rdev *rdev;
2974	sector_t sector, first_bad;
2975	int bad_sectors;
2976	if (!conf->mirrors[d].rdev \|\|
2977	!test_bit(In_sync, &conf->mirrors[d].rdev->flags))
2978	continue;
2979	/* This is where we read from */
2980	any_working = 1;
2981	rdev = conf->mirrors[d].rdev;
2982	sector = r10_bio->devs[j].addr;
2983
2984	if (is_badblock(rdev, sector, max_sync,
2985	&first_bad, &bad_sectors)) {
2986	if (first_bad > sector)
2987	max_sync = first_bad - sector;
2988	else {
2989	bad_sectors -= (sector
2990	- first_bad);
2991	if (max_sync > bad_sectors)
2992	max_sync = bad_sectors;
2993	continue;
2994	}
2995	}
2996	bio = r10_bio->devs[0].bio;
2997	bio->bi_next = biolist;
2998	biolist = bio;
2999	bio->bi_private = r10_bio;
3000	bio->bi_end_io = end_sync_read;
3001	bio->bi_rw = READ;
3002	from_addr = r10_bio->devs[j].addr;
3003	bio->bi_sector = from_addr + rdev->data_offset;
3004	bio->bi_bdev = rdev->bdev;
3005	atomic_inc(&rdev->nr_pending);
3006	/* and we write to 'i' (if not in_sync) */
3007
3008	for (k=0; k<conf->copies; k++)
3009	if (r10_bio->devs[k].devnum == i)
3010	break;
3011	BUG_ON(k == conf->copies);
3012	to_addr = r10_bio->devs[k].addr;
3013	r10_bio->devs[0].devnum = d;
3014	r10_bio->devs[0].addr = from_addr;
3015	r10_bio->devs[1].devnum = i;
3016	r10_bio->devs[1].addr = to_addr;
3017
3018	rdev = mirror->rdev;
3019	if (!test_bit(In_sync, &rdev->flags)) {
3020	bio = r10_bio->devs[1].bio;
3021	bio->bi_next = biolist;
3022	biolist = bio;
3023	bio->bi_private = r10_bio;
3024	bio->bi_end_io = end_sync_write;
3025	bio->bi_rw = WRITE;
3026	bio->bi_sector = to_addr
3027	+ rdev->data_offset;
3028	bio->bi_bdev = rdev->bdev;
3029	atomic_inc(&r10_bio->remaining);
3030	} else
3031	r10_bio->devs[1].bio->bi_end_io = NULL;
3032
3033	/* and maybe write to replacement */
3034	bio = r10_bio->devs[1].repl_bio;
3035	if (bio)
3036	bio->bi_end_io = NULL;
3037	rdev = mirror->replacement;
3038	/* Note: if rdev != NULL, then bio
3039	* cannot be NULL as r10buf_pool_alloc will
3040	* have allocated it.
3041	* So the second test here is pointless.
3042	* But it keeps semantic-checkers happy, and
3043	* this comment keeps human reviewers
3044	* happy.
3045	*/
3046	if (rdev == NULL \|\| bio == NULL \|\|
3047	test_bit(Faulty, &rdev->flags))
3048	break;
3049	bio->bi_next = biolist;
3050	biolist = bio;
3051	bio->bi_private = r10_bio;
3052	bio->bi_end_io = end_sync_write;
3053	bio->bi_rw = WRITE;
3054	bio->bi_sector = to_addr + rdev->data_offset;
3055	bio->bi_bdev = rdev->bdev;
3056	atomic_inc(&r10_bio->remaining);
3057	break;
3058	}
3059	if (j == conf->copies) {
3060	/* Cannot recover, so abort the recovery or
3061	* record a bad block */
3062	put_buf(r10_bio);
3063	if (rb2)
3064	atomic_dec(&rb2->remaining);
3065	r10_bio = rb2;
3066	if (any_working) {
3067	/* problem is that there are bad blocks
3068	* on other device(s)
3069	*/
3070	int k;
3071	for (k = 0; k < conf->copies; k++)
3072	if (r10_bio->devs[k].devnum == i)
3073	break;
3074	if (!test_bit(In_sync,
3075	&mirror->rdev->flags)
3076	&& !rdev_set_badblocks(
3077	mirror->rdev,
3078	r10_bio->devs[k].addr,
3079	max_sync, 0))
3080	any_working = 0;
3081	if (mirror->replacement &&
3082	!rdev_set_badblocks(
3083	mirror->replacement,
3084	r10_bio->devs[k].addr,
3085	max_sync, 0))
3086	any_working = 0;
3087	}
3088	if (!any_working) {
3089	if (!test_and_set_bit(MD_RECOVERY_INTR,
3090	&mddev->recovery))
3091	printk(KERN_INFO "md/raid10:%s: insufficient "
3092	"working devices for recovery.\n",
3093	mdname(mddev));
3094	mirror->recovery_disabled
3095	= mddev->recovery_disabled;
3096	}
3097	break;
3098	}
3099	}
3100	if (biolist == NULL) {
3101	while (r10_bio) {
3102	struct r10bio *rb2 = r10_bio;
3103	r10_bio = (struct r10bio*) rb2->master_bio;
3104	rb2->master_bio = NULL;
3105	put_buf(rb2);
3106	}
3107	goto giveup;
3108	}
3109	} else {
3110	/* resync. Schedule a read for every block at this virt offset */
3111	int count = 0;
3112
3113	bitmap_cond_end_sync(mddev->bitmap, sector_nr);
3114
3115	if (!bitmap_start_sync(mddev->bitmap, sector_nr,
3116	&sync_blocks, mddev->degraded) &&
3117	!conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED,
3118	&mddev->recovery)) {
3119	/* We can skip this block */
3120	*skipped = 1;
3121	return sync_blocks + sectors_skipped;
3122	}
3123	if (sync_blocks < max_sync)
3124	max_sync = sync_blocks;
3125	r10_bio = mempool_alloc(conf->r10buf_pool, GFP_NOIO);
3126
3127	r10_bio->mddev = mddev;
3128	atomic_set(&r10_bio->remaining, 0);
3129	raise_barrier(conf, 0);
3130	conf->next_resync = sector_nr;
3131
3132	r10_bio->master_bio = NULL;
3133	r10_bio->sector = sector_nr;
3134	set_bit(R10BIO_IsSync, &r10_bio->state);
3135	raid10_find_phys(conf, r10_bio);
3136	r10_bio->sectors = (sector_nr \| chunk_mask) - sector_nr + 1;
3137
3138	for (i = 0; i < conf->copies; i++) {
3139	int d = r10_bio->devs[i].devnum;
3140	sector_t first_bad, sector;
3141	int bad_sectors;
3142
3143	if (r10_bio->devs[i].repl_bio)
3144	r10_bio->devs[i].repl_bio->bi_end_io = NULL;
3145
3146	bio = r10_bio->devs[i].bio;
3147	bio->bi_end_io = NULL;
3148	clear_bit(BIO_UPTODATE, &bio->bi_flags);
3149	if (conf->mirrors[d].rdev == NULL \|\|
3150	test_bit(Faulty, &conf->mirrors[d].rdev->flags))
3151	continue;
3152	sector = r10_bio->devs[i].addr;
3153	if (is_badblock(conf->mirrors[d].rdev,
3154	sector, max_sync,
3155	&first_bad, &bad_sectors)) {
3156	if (first_bad > sector)
3157	max_sync = first_bad - sector;
3158	else {
3159	bad_sectors -= (sector - first_bad);
3160	if (max_sync > bad_sectors)
3161	max_sync = max_sync;
3162	continue;
3163	}
3164	}
3165	atomic_inc(&conf->mirrors[d].rdev->nr_pending);
3166	atomic_inc(&r10_bio->remaining);
3167	bio->bi_next = biolist;
3168	biolist = bio;
3169	bio->bi_private = r10_bio;
3170	bio->bi_end_io = end_sync_read;
3171	bio->bi_rw = READ;
3172	bio->bi_sector = sector +
3173	conf->mirrors[d].rdev->data_offset;
3174	bio->bi_bdev = conf->mirrors[d].rdev->bdev;
3175	count++;
3176
3177	if (conf->mirrors[d].replacement == NULL \|\|
3178	test_bit(Faulty,
3179	&conf->mirrors[d].replacement->flags))
3180	continue;
3181
3182	/* Need to set up for writing to the replacement */
3183	bio = r10_bio->devs[i].repl_bio;
3184	clear_bit(BIO_UPTODATE, &bio->bi_flags);
3185
3186	sector = r10_bio->devs[i].addr;
3187	atomic_inc(&conf->mirrors[d].rdev->nr_pending);
3188	bio->bi_next = biolist;
3189	biolist = bio;
3190	bio->bi_private = r10_bio;
3191	bio->bi_end_io = end_sync_write;
3192	bio->bi_rw = WRITE;
3193	bio->bi_sector = sector +
3194	conf->mirrors[d].replacement->data_offset;
3195	bio->bi_bdev = conf->mirrors[d].replacement->bdev;
3196	count++;
3197	}
3198
3199	if (count < 2) {
3200	for (i=0; i<conf->copies; i++) {
3201	int d = r10_bio->devs[i].devnum;
3202	if (r10_bio->devs[i].bio->bi_end_io)
3203	rdev_dec_pending(conf->mirrors[d].rdev,
3204	mddev);
3205	if (r10_bio->devs[i].repl_bio &&
3206	r10_bio->devs[i].repl_bio->bi_end_io)
3207	rdev_dec_pending(
3208	conf->mirrors[d].replacement,
3209	mddev);
3210	}
3211	put_buf(r10_bio);
3212	biolist = NULL;
3213	goto giveup;
3214	}
3215	}
3216
3217	for (bio = biolist; bio ; bio=bio->bi_next) {
3218
3219	bio->bi_flags &= ~(BIO_POOL_MASK - 1);
3220	if (bio->bi_end_io)
3221	bio->bi_flags \|= 1 << BIO_UPTODATE;
3222	bio->bi_vcnt = 0;
3223	bio->bi_idx = 0;
3224	bio->bi_phys_segments = 0;
3225	bio->bi_size = 0;
3226	}
3227
3228	nr_sectors = 0;
3229	if (sector_nr + max_sync < max_sector)
3230	max_sector = sector_nr + max_sync;
3231	do {
3232	struct page *page;
3233	int len = PAGE_SIZE;
3234	if (sector_nr + (len>>9) > max_sector)
3235	len = (max_sector - sector_nr) << 9;
3236	if (len == 0)
3237	break;
3238	for (bio= biolist ; bio ; bio=bio->bi_next) {
3239	struct bio *bio2;
3240	page = bio->bi_io_vec[bio->bi_vcnt].bv_page;
3241	if (bio_add_page(bio, page, len, 0))
3242	continue;
3243
3244	/* stop here */
3245	bio->bi_io_vec[bio->bi_vcnt].bv_page = page;
3246	for (bio2 = biolist;
3247	bio2 && bio2 != bio;
3248	bio2 = bio2->bi_next) {
3249	/* remove last page from this bio */
3250	bio2->bi_vcnt--;
3251	bio2->bi_size -= len;
3252	bio2->bi_flags &= ~(1<< BIO_SEG_VALID);
3253	}
3254	goto bio_full;
3255	}
3256	nr_sectors += len>>9;
3257	sector_nr += len>>9;
3258	} while (biolist->bi_vcnt < RESYNC_PAGES);
3259	bio_full:
3260	r10_bio->sectors = nr_sectors;
3261
3262	while (biolist) {
3263	bio = biolist;
3264	biolist = biolist->bi_next;
3265
3266	bio->bi_next = NULL;
3267	r10_bio = bio->bi_private;
3268	r10_bio->sectors = nr_sectors;
3269
3270	if (bio->bi_end_io == end_sync_read) {
3271	md_sync_acct(bio->bi_bdev, nr_sectors);
3272	generic_make_request(bio);
3273	}
3274	}
3275
3276	if (sectors_skipped)
3277	/* pretend they weren't skipped, it makes
3278	* no important difference in this case
3279	*/
3280	md_done_sync(mddev, sectors_skipped, 1);
3281
3282	return sectors_skipped + nr_sectors;
3283	giveup:
3284	/* There is nowhere to write, so all non-sync
3285	* drives must be failed or in resync, all drives
3286	* have a bad block, so try the next chunk...
3287	*/
3288	if (sector_nr + max_sync < max_sector)
3289	max_sector = sector_nr + max_sync;
3290
3291	sectors_skipped += (max_sector - sector_nr);
3292	chunks_skipped ++;
3293	sector_nr = max_sector;
3294	goto skipped;
3295	}
3296
3297	static sector_t
3298	raid10_size(struct mddev *mddev, sector_t sectors, int raid_disks)
3299	{
3300	sector_t size;
3301	struct r10conf *conf = mddev->private;
3302
3303	if (!raid_disks)
3304	raid_disks = min(conf->geo.raid_disks,
3305	conf->prev.raid_disks);
3306	if (!sectors)
3307	sectors = conf->dev_sectors;
3308
3309	size = sectors >> conf->geo.chunk_shift;
3310	sector_div(size, conf->geo.far_copies);
3311	size = size * raid_disks;
3312	sector_div(size, conf->geo.near_copies);
3313
3314	return size << conf->geo.chunk_shift;
3315	}
3316
3317	static void calc_sectors(struct r10conf *conf, sector_t size)
3318	{
3319	/* Calculate the number of sectors-per-device that will
3320	* actually be used, and set conf->dev_sectors and
3321	* conf->stride
3322	*/
3323
3324	size = size >> conf->geo.chunk_shift;
3325	sector_div(size, conf->geo.far_copies);
3326	size = size * conf->geo.raid_disks;
3327	sector_div(size, conf->geo.near_copies);
3328	/* 'size' is now the number of chunks in the array */
3329	/* calculate "used chunks per device" */
3330	size = size * conf->copies;
3331
3332	/* We need to round up when dividing by raid_disks to
3333	* get the stride size.
3334	*/
3335	size = DIV_ROUND_UP_SECTOR_T(size, conf->geo.raid_disks);
3336
3337	conf->dev_sectors = size << conf->geo.chunk_shift;
3338
3339	if (conf->geo.far_offset)
3340	conf->geo.stride = 1 << conf->geo.chunk_shift;
3341	else {
3342	sector_div(size, conf->geo.far_copies);
3343	conf->geo.stride = size << conf->geo.chunk_shift;
3344	}
3345	}
3346
3347	enum geo_type {geo_new, geo_old, geo_start};
3348	static int setup_geo(struct geom geo, struct mddev mddev, enum geo_type new)
3349	{
3350	int nc, fc, fo;
3351	int layout, chunk, disks;
3352	switch (new) {
3353	case geo_old:
3354	layout = mddev->layout;
3355	chunk = mddev->chunk_sectors;
3356	disks = mddev->raid_disks - mddev->delta_disks;
3357	break;
3358	case geo_new:
3359	layout = mddev->new_layout;
3360	chunk = mddev->new_chunk_sectors;
3361	disks = mddev->raid_disks;
3362	break;
3363	default: /* avoid 'may be unused' warnings */
3364	case geo_start: /* new when starting reshape - raid_disks not
3365	* updated yet. */
3366	layout = mddev->new_layout;
3367	chunk = mddev->new_chunk_sectors;
3368	disks = mddev->raid_disks + mddev->delta_disks;
3369	break;
3370	}
3371	if (layout >> 17)
3372	return -1;
3373	if (chunk < (PAGE_SIZE >> 9) \|\|
3374	!is_power_of_2(chunk))
3375	return -2;
3376	nc = layout & 255;
3377	fc = (layout >> 8) & 255;
3378	fo = layout & (1<<16);
3379	geo->raid_disks = disks;
3380	geo->near_copies = nc;
3381	geo->far_copies = fc;
3382	geo->far_offset = fo;
3383	geo->chunk_mask = chunk - 1;
3384	geo->chunk_shift = ffz(~chunk);
3385	return nc*fc;
3386	}
3387
3388	static struct r10conf setup_conf(struct mddev mddev)
3389	{
3390	struct r10conf *conf = NULL;
3391	int err = -EINVAL;
3392	struct geom geo;
3393	int copies;
3394
3395	copies = setup_geo(&geo, mddev, geo_new);
3396
3397	if (copies == -2) {
3398	printk(KERN_ERR "md/raid10:%s: chunk size must be "
3399	"at least PAGE_SIZE(%ld) and be a power of 2.\n",
3400	mdname(mddev), PAGE_SIZE);
3401	goto out;
3402	}
3403
3404	if (copies < 2 \|\| copies > mddev->raid_disks) {
3405	printk(KERN_ERR "md/raid10:%s: unsupported raid10 layout: 0x%8x\n",
3406	mdname(mddev), mddev->new_layout);
3407	goto out;
3408	}
3409
3410	err = -ENOMEM;
3411	conf = kzalloc(sizeof(struct r10conf), GFP_KERNEL);
3412	if (!conf)
3413	goto out;
3414
3415	/* FIXME calc properly */
3416	conf->mirrors = kzalloc(sizeof(struct raid10_info)*(mddev->raid_disks +
3417	max(0,mddev->delta_disks)),
3418	GFP_KERNEL);
3419	if (!conf->mirrors)
3420	goto out;
3421
3422	conf->tmppage = alloc_page(GFP_KERNEL);
3423	if (!conf->tmppage)
3424	goto out;
3425
3426	conf->geo = geo;
3427	conf->copies = copies;
3428	conf->r10bio_pool = mempool_create(NR_RAID10_BIOS, r10bio_pool_alloc,
3429	r10bio_pool_free, conf);
3430	if (!conf->r10bio_pool)
3431	goto out;
3432
3433	calc_sectors(conf, mddev->dev_sectors);
3434	if (mddev->reshape_position == MaxSector) {
3435	conf->prev = conf->geo;
3436	conf->reshape_progress = MaxSector;
3437	} else {
3438	if (setup_geo(&conf->prev, mddev, geo_old) != conf->copies) {
3439	err = -EINVAL;
3440	goto out;
3441	}
3442	conf->reshape_progress = mddev->reshape_position;
3443	if (conf->prev.far_offset)
3444	conf->prev.stride = 1 << conf->prev.chunk_shift;
3445	else
3446	/* far_copies must be 1 */
3447	conf->prev.stride = conf->dev_sectors;
3448	}
3449	spin_lock_init(&conf->device_lock);
3450	INIT_LIST_HEAD(&conf->retry_list);
3451
3452	spin_lock_init(&conf->resync_lock);
3453	init_waitqueue_head(&conf->wait_barrier);
3454
3455	conf->thread = md_register_thread(raid10d, mddev, "raid10");
3456	if (!conf->thread)
3457	goto out;
3458
3459	conf->mddev = mddev;
3460	return conf;
3461
3462	out:
3463	if (err == -ENOMEM)
3464	printk(KERN_ERR "md/raid10:%s: couldn't allocate memory.\n",
3465	mdname(mddev));
3466	if (conf) {
3467	if (conf->r10bio_pool)
3468	mempool_destroy(conf->r10bio_pool);
3469	kfree(conf->mirrors);
3470	safe_put_page(conf->tmppage);
3471	kfree(conf);
3472	}
3473	return ERR_PTR(err);
3474	}
3475
3476	static int run(struct mddev *mddev)
3477	{
3478	struct r10conf *conf;
3479	int i, disk_idx, chunk_size;
3480	struct raid10_info *disk;
3481	struct md_rdev *rdev;
3482	sector_t size;
3483	sector_t min_offset_diff = 0;
3484	int first = 1;
3485
3486	if (mddev->private == NULL) {
3487	conf = setup_conf(mddev);
3488	if (IS_ERR(conf))
3489	return PTR_ERR(conf);
3490	mddev->private = conf;
3491	}
3492	conf = mddev->private;
3493	if (!conf)
3494	goto out;
3495
3496	mddev->thread = conf->thread;
3497	conf->thread = NULL;
3498
3499	chunk_size = mddev->chunk_sectors << 9;
3500	if (mddev->queue) {
3501	blk_queue_io_min(mddev->queue, chunk_size);
3502	if (conf->geo.raid_disks % conf->geo.near_copies)
3503	blk_queue_io_opt(mddev->queue, chunk_size * conf->geo.raid_disks);
3504	else
3505	blk_queue_io_opt(mddev->queue, chunk_size *
3506	(conf->geo.raid_disks / conf->geo.near_copies));
3507	}
3508
3509	rdev_for_each(rdev, mddev) {
3510	long long diff;
3511	struct request_queue *q;
3512
3513	disk_idx = rdev->raid_disk;
3514	if (disk_idx < 0)
3515	continue;
3516	if (disk_idx >= conf->geo.raid_disks &&
3517	disk_idx >= conf->prev.raid_disks)
3518	continue;
3519	disk = conf->mirrors + disk_idx;
3520
3521	if (test_bit(Replacement, &rdev->flags)) {
3522	if (disk->replacement)
3523	goto out_free_conf;
3524	disk->replacement = rdev;
3525	} else {
3526	if (disk->rdev)
3527	goto out_free_conf;
3528	disk->rdev = rdev;
3529	}
3530	q = bdev_get_queue(rdev->bdev);
3531	if (q->merge_bvec_fn)
3532	mddev->merge_check_needed = 1;
3533	diff = (rdev->new_data_offset - rdev->data_offset);
3534	if (!mddev->reshape_backwards)
3535	diff = -diff;
3536	if (diff < 0)
3537	diff = 0;
3538	if (first \|\| diff < min_offset_diff)
3539	min_offset_diff = diff;
3540
3541	if (mddev->gendisk)
3542	disk_stack_limits(mddev->gendisk, rdev->bdev,
3543	rdev->data_offset << 9);
3544
3545	disk->head_position = 0;
3546	}
3547
3548	/* need to check that every block has at least one working mirror */
3549	if (!enough(conf, -1)) {
3550	printk(KERN_ERR "md/raid10:%s: not enough operational mirrors.\n",
3551	mdname(mddev));
3552	goto out_free_conf;
3553	}
3554
3555	if (conf->reshape_progress != MaxSector) {
3556	/* must ensure that shape change is supported */
3557	if (conf->geo.far_copies != 1 &&
3558	conf->geo.far_offset == 0)
3559	goto out_free_conf;
3560	if (conf->prev.far_copies != 1 &&
3561	conf->geo.far_offset == 0)
3562	goto out_free_conf;
3563	}
3564
3565	mddev->degraded = 0;
3566	for (i = 0;
3567	i < conf->geo.raid_disks
3568	\|\| i < conf->prev.raid_disks;
3569	i++) {
3570
3571	disk = conf->mirrors + i;
3572
3573	if (!disk->rdev && disk->replacement) {
3574	/* The replacement is all we have - use it */
3575	disk->rdev = disk->replacement;
3576	disk->replacement = NULL;
3577	clear_bit(Replacement, &disk->rdev->flags);
3578	}
3579
3580	if (!disk->rdev \|\|
3581	!test_bit(In_sync, &disk->rdev->flags)) {
3582	disk->head_position = 0;
3583	mddev->degraded++;
3584	if (disk->rdev)
3585	conf->fullsync = 1;
3586	}
3587	disk->recovery_disabled = mddev->recovery_disabled - 1;
3588	}
3589
3590	if (mddev->recovery_cp != MaxSector)
3591	printk(KERN_NOTICE "md/raid10:%s: not clean"
3592	" -- starting background reconstruction\n",
3593	mdname(mddev));
3594	printk(KERN_INFO
3595	"md/raid10:%s: active with %d out of %d devices\n",
3596	mdname(mddev), conf->geo.raid_disks - mddev->degraded,
3597	conf->geo.raid_disks);
3598	/*
3599	* Ok, everything is just fine now
3600	*/
3601	mddev->dev_sectors = conf->dev_sectors;
3602	size = raid10_size(mddev, 0, 0);
3603	md_set_array_sectors(mddev, size);
3604	mddev->resync_max_sectors = size;
3605
3606	if (mddev->queue) {
3607	int stripe = conf->geo.raid_disks *
3608	((mddev->chunk_sectors << 9) / PAGE_SIZE);
3609	mddev->queue->backing_dev_info.congested_fn = raid10_congested;
3610	mddev->queue->backing_dev_info.congested_data = mddev;
3611
3612	/* Calculate max read-ahead size.
3613	* We need to readahead at least twice a whole stripe....
3614	* maybe...
3615	*/
3616	stripe /= conf->geo.near_copies;
3617	if (mddev->queue->backing_dev_info.ra_pages < 2 * stripe)
3618	mddev->queue->backing_dev_info.ra_pages = 2 * stripe;
3619	blk_queue_merge_bvec(mddev->queue, raid10_mergeable_bvec);
3620	}
3621
3622
3623	if (md_integrity_register(mddev))
3624	goto out_free_conf;
3625
3626	if (conf->reshape_progress != MaxSector) {
3627	unsigned long before_length, after_length;
3628
3629	before_length = ((1 << conf->prev.chunk_shift) *
3630	conf->prev.far_copies);
3631	after_length = ((1 << conf->geo.chunk_shift) *
3632	conf->geo.far_copies);
3633
3634	if (max(before_length, after_length) > min_offset_diff) {
3635	/* This cannot work */
3636	printk("md/raid10: offset difference not enough to continue reshape\n");
3637	goto out_free_conf;
3638	}
3639	conf->offset_diff = min_offset_diff;
3640
3641	conf->reshape_safe = conf->reshape_progress;
3642	clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
3643	clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
3644	set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
3645	set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
3646	mddev->sync_thread = md_register_thread(md_do_sync, mddev,
3647	"reshape");
3648	}
3649
3650	return 0;
3651
3652	out_free_conf:
3653	md_unregister_thread(&mddev->thread);
3654	if (conf->r10bio_pool)
3655	mempool_destroy(conf->r10bio_pool);
3656	safe_put_page(conf->tmppage);
3657	kfree(conf->mirrors);
3658	kfree(conf);
3659	mddev->private = NULL;
3660	out:
3661	return -EIO;
3662	}
3663
3664	static int stop(struct mddev *mddev)
3665	{
3666	struct r10conf *conf = mddev->private;
3667
3668	raise_barrier(conf, 0);
3669	lower_barrier(conf);
3670
3671	md_unregister_thread(&mddev->thread);
3672	if (mddev->queue)
3673	/* the unplug fn references 'conf'*/
3674	blk_sync_queue(mddev->queue);
3675
3676	if (conf->r10bio_pool)
3677	mempool_destroy(conf->r10bio_pool);
3678	kfree(conf->mirrors);
3679	kfree(conf);
3680	mddev->private = NULL;
3681	return 0;
3682	}
3683
3684	static void raid10_quiesce(struct mddev *mddev, int state)
3685	{
3686	struct r10conf *conf = mddev->private;
3687
3688	switch(state) {
3689	case 1:
3690	raise_barrier(conf, 0);
3691	break;
3692	case 0:
3693	lower_barrier(conf);
3694	break;
3695	}
3696	}
3697
3698	static int raid10_resize(struct mddev *mddev, sector_t sectors)
3699	{
3700	/* Resize of 'far' arrays is not supported.
3701	* For 'near' and 'offset' arrays we can set the
3702	* number of sectors used to be an appropriate multiple
3703	* of the chunk size.
3704	* For 'offset', this is far_copies*chunksize.
3705	* For 'near' the multiplier is the LCM of
3706	* near_copies and raid_disks.
3707	* So if far_copies > 1 && !far_offset, fail.
3708	* Else find LCM(raid_disks, near_copy)*far_copies and
3709	* multiply by chunk_size. Then round to this number.
3710	* This is mostly done by raid10_size()
3711	*/
3712	struct r10conf *conf = mddev->private;
3713	sector_t oldsize, size;
3714
3715	if (mddev->reshape_position != MaxSector)
3716	return -EBUSY;
3717
3718	if (conf->geo.far_copies > 1 && !conf->geo.far_offset)
3719	return -EINVAL;
3720
3721	oldsize = raid10_size(mddev, 0, 0);
3722	size = raid10_size(mddev, sectors, 0);
3723	if (mddev->external_size &&
3724	mddev->array_sectors > size)
3725	return -EINVAL;
3726	if (mddev->bitmap) {
3727	int ret = bitmap_resize(mddev->bitmap, size, 0, 0);
3728	if (ret)
3729	return ret;
3730	}
3731	md_set_array_sectors(mddev, size);
3732	set_capacity(mddev->gendisk, mddev->array_sectors);
3733	revalidate_disk(mddev->gendisk);
3734	if (sectors > mddev->dev_sectors &&
3735	mddev->recovery_cp > oldsize) {
3736	mddev->recovery_cp = oldsize;
3737	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
3738	}
3739	calc_sectors(conf, sectors);
3740	mddev->dev_sectors = conf->dev_sectors;
3741	mddev->resync_max_sectors = size;
3742	return 0;
3743	}
3744
3745	static void raid10_takeover_raid0(struct mddev mddev)
3746	{
3747	struct md_rdev *rdev;
3748	struct r10conf *conf;
3749
3750	if (mddev->degraded > 0) {
3751	printk(KERN_ERR "md/raid10:%s: Error: degraded raid0!\n",
3752	mdname(mddev));
3753	return ERR_PTR(-EINVAL);
3754	}
3755
3756	/* Set new parameters */
3757	mddev->new_level = 10;
3758	/* new layout: far_copies = 1, near_copies = 2 */
3759	mddev->new_layout = (1<<8) + 2;
3760	mddev->new_chunk_sectors = mddev->chunk_sectors;
3761	mddev->delta_disks = mddev->raid_disks;
3762	mddev->raid_disks *= 2;
3763	/* make sure it will be not marked as dirty */
3764	mddev->recovery_cp = MaxSector;
3765
3766	conf = setup_conf(mddev);
3767	if (!IS_ERR(conf)) {
3768	rdev_for_each(rdev, mddev)
3769	if (rdev->raid_disk >= 0)
3770	rdev->new_raid_disk = rdev->raid_disk * 2;
3771	conf->barrier = 1;
3772	}
3773
3774	return conf;
3775	}
3776
3777	static void raid10_takeover(struct mddev mddev)
3778	{
3779	struct r0conf *raid0_conf;
3780
3781	/* raid10 can take over:
3782	* raid0 - providing it has only two drives
3783	*/
3784	if (mddev->level == 0) {
3785	/* for raid0 takeover only one zone is supported */
3786	raid0_conf = mddev->private;
3787	if (raid0_conf->nr_strip_zones > 1) {
3788	printk(KERN_ERR "md/raid10:%s: cannot takeover raid 0"
3789	" with more than one zone.\n",
3790	mdname(mddev));
3791	return ERR_PTR(-EINVAL);
3792	}
3793	return raid10_takeover_raid0(mddev);
3794	}
3795	return ERR_PTR(-EINVAL);
3796	}
3797
3798	static int raid10_check_reshape(struct mddev *mddev)
3799	{
3800	/* Called when there is a request to change
3801	* - layout (to ->new_layout)
3802	* - chunk size (to ->new_chunk_sectors)
3803	* - raid_disks (by delta_disks)
3804	* or when trying to restart a reshape that was ongoing.
3805	*
3806	* We need to validate the request and possibly allocate
3807	* space if that might be an issue later.
3808	*
3809	* Currently we reject any reshape of a 'far' mode array,
3810	* allow chunk size to change if new is generally acceptable,
3811	* allow raid_disks to increase, and allow
3812	* a switch between 'near' mode and 'offset' mode.
3813	*/
3814	struct r10conf *conf = mddev->private;
3815	struct geom geo;
3816
3817	if (conf->geo.far_copies != 1 && !conf->geo.far_offset)
3818	return -EINVAL;
3819
3820	if (setup_geo(&geo, mddev, geo_start) != conf->copies)
3821	/* mustn't change number of copies */
3822	return -EINVAL;
3823	if (geo.far_copies > 1 && !geo.far_offset)
3824	/* Cannot switch to 'far' mode */
3825	return -EINVAL;
3826
3827	if (mddev->array_sectors & geo.chunk_mask)
3828	/* not factor of array size */
3829	return -EINVAL;
3830
3831	if (!enough(conf, -1))
3832	return -EINVAL;
3833
3834	kfree(conf->mirrors_new);
3835	conf->mirrors_new = NULL;
3836	if (mddev->delta_disks > 0) {
3837	/* allocate new 'mirrors' list */
3838	conf->mirrors_new = kzalloc(
3839	sizeof(struct raid10_info)
3840	*(mddev->raid_disks +
3841	mddev->delta_disks),
3842	GFP_KERNEL);
3843	if (!conf->mirrors_new)
3844	return -ENOMEM;
3845	}
3846	return 0;
3847	}
3848
3849	/*
3850	* Need to check if array has failed when deciding whether to:
3851	* - start an array
3852	* - remove non-faulty devices
3853	* - add a spare
3854	* - allow a reshape
3855	* This determination is simple when no reshape is happening.
3856	* However if there is a reshape, we need to carefully check
3857	* both the before and after sections.
3858	* This is because some failed devices may only affect one
3859	* of the two sections, and some non-in_sync devices may
3860	* be insync in the section most affected by failed devices.
3861	*/
3862	static int calc_degraded(struct r10conf *conf)
3863	{
3864	int degraded, degraded2;
3865	int i;
3866
3867	rcu_read_lock();
3868	degraded = 0;
3869	/* 'prev' section first */
3870	for (i = 0; i < conf->prev.raid_disks; i++) {
3871	struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
3872	if (!rdev \|\| test_bit(Faulty, &rdev->flags))
3873	degraded++;
3874	else if (!test_bit(In_sync, &rdev->flags))
3875	/* When we can reduce the number of devices in
3876	* an array, this might not contribute to
3877	* 'degraded'. It does now.
3878	*/
3879	degraded++;
3880	}
3881	rcu_read_unlock();
3882	if (conf->geo.raid_disks == conf->prev.raid_disks)
3883	return degraded;
3884	rcu_read_lock();
3885	degraded2 = 0;
3886	for (i = 0; i < conf->geo.raid_disks; i++) {
3887	struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
3888	if (!rdev \|\| test_bit(Faulty, &rdev->flags))
3889	degraded2++;
3890	else if (!test_bit(In_sync, &rdev->flags)) {
3891	/* If reshape is increasing the number of devices,
3892	* this section has already been recovered, so
3893	* it doesn't contribute to degraded.
3894	* else it does.
3895	*/
3896	if (conf->geo.raid_disks <= conf->prev.raid_disks)
3897	degraded2++;
3898	}
3899	}
3900	rcu_read_unlock();
3901	if (degraded2 > degraded)
3902	return degraded2;
3903	return degraded;
3904	}
3905
3906	static int raid10_start_reshape(struct mddev *mddev)
3907	{
3908	/* A 'reshape' has been requested. This commits
3909	* the various 'new' fields and sets MD_RECOVER_RESHAPE
3910	* This also checks if there are enough spares and adds them
3911	* to the array.
3912	* We currently require enough spares to make the final
3913	* array non-degraded. We also require that the difference
3914	* between old and new data_offset - on each device - is
3915	* enough that we never risk over-writing.
3916	*/
3917
3918	unsigned long before_length, after_length;
3919	sector_t min_offset_diff = 0;
3920	int first = 1;
3921	struct geom new;
3922	struct r10conf *conf = mddev->private;
3923	struct md_rdev *rdev;
3924	int spares = 0;
3925	int ret;
3926
3927	if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
3928	return -EBUSY;
3929
3930	if (setup_geo(&new, mddev, geo_start) != conf->copies)
3931	return -EINVAL;
3932
3933	before_length = ((1 << conf->prev.chunk_shift) *
3934	conf->prev.far_copies);
3935	after_length = ((1 << conf->geo.chunk_shift) *
3936	conf->geo.far_copies);
3937
3938	rdev_for_each(rdev, mddev) {
3939	if (!test_bit(In_sync, &rdev->flags)
3940	&& !test_bit(Faulty, &rdev->flags))
3941	spares++;
3942	if (rdev->raid_disk >= 0) {
3943	long long diff = (rdev->new_data_offset
3944	- rdev->data_offset);
3945	if (!mddev->reshape_backwards)
3946	diff = -diff;
3947	if (diff < 0)
3948	diff = 0;
3949	if (first \|\| diff < min_offset_diff)
3950	min_offset_diff = diff;
3951	}
3952	}
3953
3954	if (max(before_length, after_length) > min_offset_diff)
3955	return -EINVAL;
3956
3957	if (spares < mddev->delta_disks)
3958	return -EINVAL;
3959
3960	conf->offset_diff = min_offset_diff;
3961	spin_lock_irq(&conf->device_lock);
3962	if (conf->mirrors_new) {
3963	memcpy(conf->mirrors_new, conf->mirrors,
3964	sizeof(struct raid10_info)*conf->prev.raid_disks);
3965	smp_mb();
3966	kfree(conf->mirrors_old); /* FIXME and elsewhere */
3967	conf->mirrors_old = conf->mirrors;
3968	conf->mirrors = conf->mirrors_new;
3969	conf->mirrors_new = NULL;
3970	}
3971	setup_geo(&conf->geo, mddev, geo_start);
3972	smp_mb();
3973	if (mddev->reshape_backwards) {
3974	sector_t size = raid10_size(mddev, 0, 0);
3975	if (size < mddev->array_sectors) {
3976	spin_unlock_irq(&conf->device_lock);
3977	printk(KERN_ERR "md/raid10:%s: array size must be reduce before number of disks\n",
3978	mdname(mddev));
3979	return -EINVAL;
3980	}
3981	mddev->resync_max_sectors = size;
3982	conf->reshape_progress = size;
3983	} else
3984	conf->reshape_progress = 0;
3985	spin_unlock_irq(&conf->device_lock);
3986
3987	if (mddev->delta_disks && mddev->bitmap) {
3988	ret = bitmap_resize(mddev->bitmap,
3989	raid10_size(mddev, 0,
3990	conf->geo.raid_disks),
3991	0, 0);
3992	if (ret)
3993	goto abort;
3994	}
3995	if (mddev->delta_disks > 0) {
3996	rdev_for_each(rdev, mddev)
3997	if (rdev->raid_disk < 0 &&
3998	!test_bit(Faulty, &rdev->flags)) {
3999	if (raid10_add_disk(mddev, rdev) == 0) {
4000	if (rdev->raid_disk >=
4001	conf->prev.raid_disks)
4002	set_bit(In_sync, &rdev->flags);
4003	else
4004	rdev->recovery_offset = 0;
4005
4006	if (sysfs_link_rdev(mddev, rdev))
4007	/* Failure here is OK */;
4008	}
4009	} else if (rdev->raid_disk >= conf->prev.raid_disks
4010	&& !test_bit(Faulty, &rdev->flags)) {
4011	/* This is a spare that was manually added */
4012	set_bit(In_sync, &rdev->flags);
4013	}
4014	}
4015	/* When a reshape changes the number of devices,
4016	* ->degraded is measured against the larger of the
4017	* pre and post numbers.
4018	*/
4019	spin_lock_irq(&conf->device_lock);
4020	mddev->degraded = calc_degraded(conf);
4021	spin_unlock_irq(&conf->device_lock);
4022	mddev->raid_disks = conf->geo.raid_disks;
4023	mddev->reshape_position = conf->reshape_progress;
4024	set_bit(MD_CHANGE_DEVS, &mddev->flags);
4025
4026	clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
4027	clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
4028	set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
4029	set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
4030
4031	mddev->sync_thread = md_register_thread(md_do_sync, mddev,
4032	"reshape");
4033	if (!mddev->sync_thread) {
4034	ret = -EAGAIN;
4035	goto abort;
4036	}
4037	conf->reshape_checkpoint = jiffies;
4038	md_wakeup_thread(mddev->sync_thread);
4039	md_new_event(mddev);
4040	return 0;
4041
4042	abort:
4043	mddev->recovery = 0;
4044	spin_lock_irq(&conf->device_lock);
4045	conf->geo = conf->prev;
4046	mddev->raid_disks = conf->geo.raid_disks;
4047	rdev_for_each(rdev, mddev)
4048	rdev->new_data_offset = rdev->data_offset;
4049	smp_wmb();
4050	conf->reshape_progress = MaxSector;
4051	mddev->reshape_position = MaxSector;
4052	spin_unlock_irq(&conf->device_lock);
4053	return ret;
4054	}
4055
4056	/* Calculate the last device-address that could contain
4057	* any block from the chunk that includes the array-address 's'
4058	* and report the next address.
4059	* i.e. the address returned will be chunk-aligned and after
4060	* any data that is in the chunk containing 's'.
4061	*/
4062	static sector_t last_dev_address(sector_t s, struct geom *geo)
4063	{
4064	s = (s \| geo->chunk_mask) + 1;
4065	s >>= geo->chunk_shift;
4066	s *= geo->near_copies;
4067	s = DIV_ROUND_UP_SECTOR_T(s, geo->raid_disks);
4068	s *= geo->far_copies;
4069	s <<= geo->chunk_shift;
4070	return s;
4071	}
4072
4073	/* Calculate the first device-address that could contain
4074	* any block from the chunk that includes the array-address 's'.
4075	* This too will be the start of a chunk
4076	*/
4077	static sector_t first_dev_address(sector_t s, struct geom *geo)
4078	{
4079	s >>= geo->chunk_shift;
4080	s *= geo->near_copies;
4081	sector_div(s, geo->raid_disks);
4082	s *= geo->far_copies;
4083	s <<= geo->chunk_shift;
4084	return s;
4085	}
4086
4087	static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr,
4088	int *skipped)
4089	{
4090	/* We simply copy at most one chunk (smallest of old and new)
4091	* at a time, possibly less if that exceeds RESYNC_PAGES,
4092	* or we hit a bad block or something.
4093	* This might mean we pause for normal IO in the middle of
4094	* a chunk, but that is not a problem was mddev->reshape_position
4095	* can record any location.
4096	*
4097	* If we will want to write to a location that isn't
4098	* yet recorded as 'safe' (i.e. in metadata on disk) then
4099	* we need to flush all reshape requests and update the metadata.
4100	*
4101	* When reshaping forwards (e.g. to more devices), we interpret
4102	* 'safe' as the earliest block which might not have been copied
4103	* down yet. We divide this by previous stripe size and multiply
4104	* by previous stripe length to get lowest device offset that we
4105	* cannot write to yet.
4106	* We interpret 'sector_nr' as an address that we want to write to.
4107	* From this we use last_device_address() to find where we might
4108	* write to, and first_device_address on the 'safe' position.
4109	* If this 'next' write position is after the 'safe' position,
4110	* we must update the metadata to increase the 'safe' position.
4111	*
4112	* When reshaping backwards, we round in the opposite direction
4113	* and perform the reverse test: next write position must not be
4114	* less than current safe position.
4115	*
4116	* In all this the minimum difference in data offsets
4117	* (conf->offset_diff - always positive) allows a bit of slack,
4118	* so next can be after 'safe', but not by more than offset_disk
4119	*
4120	* We need to prepare all the bios here before we start any IO
4121	* to ensure the size we choose is acceptable to all devices.
4122	* The means one for each copy for write-out and an extra one for
4123	* read-in.
4124	* We store the read-in bio in ->master_bio and the others in
4125	* ->devs[x].bio and ->devs[x].repl_bio.
4126	*/
4127	struct r10conf *conf = mddev->private;
4128	struct r10bio *r10_bio;
4129	sector_t next, safe, last;
4130	int max_sectors;
4131	int nr_sectors;
4132	int s;
4133	struct md_rdev *rdev;
4134	int need_flush = 0;
4135	struct bio *blist;
4136	struct bio bio, read_bio;
4137	int sectors_done = 0;
4138
4139	if (sector_nr == 0) {
4140	/* If restarting in the middle, skip the initial sectors */
4141	if (mddev->reshape_backwards &&
4142	conf->reshape_progress < raid10_size(mddev, 0, 0)) {
4143	sector_nr = (raid10_size(mddev, 0, 0)
4144	- conf->reshape_progress);
4145	} else if (!mddev->reshape_backwards &&
4146	conf->reshape_progress > 0)
4147	sector_nr = conf->reshape_progress;
4148	if (sector_nr) {
4149	mddev->curr_resync_completed = sector_nr;
4150	sysfs_notify(&mddev->kobj, NULL, "sync_completed");
4151	*skipped = 1;
4152	return sector_nr;
4153	}
4154	}
4155
4156	/* We don't use sector_nr to track where we are up to
4157	* as that doesn't work well for ->reshape_backwards.
4158	* So just use ->reshape_progress.
4159	*/
4160	if (mddev->reshape_backwards) {
4161	/* 'next' is the earliest device address that we might
4162	* write to for this chunk in the new layout
4163	*/
4164	next = first_dev_address(conf->reshape_progress - 1,
4165	&conf->geo);
4166
4167	/* 'safe' is the last device address that we might read from
4168	* in the old layout after a restart
4169	*/
4170	safe = last_dev_address(conf->reshape_safe - 1,
4171	&conf->prev);
4172
4173	if (next + conf->offset_diff < safe)
4174	need_flush = 1;
4175
4176	last = conf->reshape_progress - 1;
4177	sector_nr = last & ~(sector_t)(conf->geo.chunk_mask
4178	& conf->prev.chunk_mask);
4179	if (sector_nr + RESYNC_BLOCK_SIZE/512 < last)
4180	sector_nr = last + 1 - RESYNC_BLOCK_SIZE/512;
4181	} else {
4182	/* 'next' is after the last device address that we
4183	* might write to for this chunk in the new layout
4184	*/
4185	next = last_dev_address(conf->reshape_progress, &conf->geo);
4186
4187	/* 'safe' is the earliest device address that we might
4188	* read from in the old layout after a restart
4189	*/
4190	safe = first_dev_address(conf->reshape_safe, &conf->prev);
4191
4192	/* Need to update metadata if 'next' might be beyond 'safe'
4193	* as that would possibly corrupt data
4194	*/
4195	if (next > safe + conf->offset_diff)
4196	need_flush = 1;
4197
4198	sector_nr = conf->reshape_progress;
4199	last = sector_nr \| (conf->geo.chunk_mask
4200	& conf->prev.chunk_mask);
4201
4202	if (sector_nr + RESYNC_BLOCK_SIZE/512 <= last)
4203	last = sector_nr + RESYNC_BLOCK_SIZE/512 - 1;
4204	}
4205
4206	if (need_flush \|\|
4207	time_after(jiffies, conf->reshape_checkpoint + 10*HZ)) {
4208	/* Need to update reshape_position in metadata */
4209	wait_barrier(conf);
4210	mddev->reshape_position = conf->reshape_progress;
4211	if (mddev->reshape_backwards)
4212	mddev->curr_resync_completed = raid10_size(mddev, 0, 0)
4213	- conf->reshape_progress;
4214	else
4215	mddev->curr_resync_completed = conf->reshape_progress;
4216	conf->reshape_checkpoint = jiffies;
4217	set_bit(MD_CHANGE_DEVS, &mddev->flags);
4218	md_wakeup_thread(mddev->thread);
4219	wait_event(mddev->sb_wait, mddev->flags == 0 \|\|
4220	kthread_should_stop());
4221	conf->reshape_safe = mddev->reshape_position;
4222	allow_barrier(conf);
4223	}
4224
4225	read_more:
4226	/* Now schedule reads for blocks from sector_nr to last */
4227	r10_bio = mempool_alloc(conf->r10buf_pool, GFP_NOIO);
4228	raise_barrier(conf, sectors_done != 0);
4229	atomic_set(&r10_bio->remaining, 0);
4230	r10_bio->mddev = mddev;
4231	r10_bio->sector = sector_nr;
4232	set_bit(R10BIO_IsReshape, &r10_bio->state);
4233	r10_bio->sectors = last - sector_nr + 1;
4234	rdev = read_balance(conf, r10_bio, &max_sectors);
4235	BUG_ON(!test_bit(R10BIO_Previous, &r10_bio->state));
4236
4237	if (!rdev) {
4238	/* Cannot read from here, so need to record bad blocks
4239	* on all the target devices.
4240	*/
4241	// FIXME
4242	set_bit(MD_RECOVERY_INTR, &mddev->recovery);
4243	return sectors_done;
4244	}
4245
4246	read_bio = bio_alloc_mddev(GFP_KERNEL, RESYNC_PAGES, mddev);
4247
4248	read_bio->bi_bdev = rdev->bdev;
4249	read_bio->bi_sector = (r10_bio->devs[r10_bio->read_slot].addr
4250	+ rdev->data_offset);
4251	read_bio->bi_private = r10_bio;
4252	read_bio->bi_end_io = end_sync_read;
4253	read_bio->bi_rw = READ;
4254	read_bio->bi_flags &= ~(BIO_POOL_MASK - 1);
4255	read_bio->bi_flags \|= 1 << BIO_UPTODATE;
4256	read_bio->bi_vcnt = 0;
4257	read_bio->bi_idx = 0;
4258	read_bio->bi_size = 0;
4259	r10_bio->master_bio = read_bio;
4260	r10_bio->read_slot = r10_bio->devs[r10_bio->read_slot].devnum;
4261
4262	/* Now find the locations in the new layout */
4263	__raid10_find_phys(&conf->geo, r10_bio);
4264
4265	blist = read_bio;
4266	read_bio->bi_next = NULL;
4267
4268	for (s = 0; s < conf->copies*2; s++) {
4269	struct bio *b;
4270	int d = r10_bio->devs[s/2].devnum;
4271	struct md_rdev *rdev2;
4272	if (s&1) {
4273	rdev2 = conf->mirrors[d].replacement;
4274	b = r10_bio->devs[s/2].repl_bio;
4275	} else {
4276	rdev2 = conf->mirrors[d].rdev;
4277	b = r10_bio->devs[s/2].bio;
4278	}
4279	if (!rdev2 \|\| test_bit(Faulty, &rdev2->flags))
4280	continue;
4281	b->bi_bdev = rdev2->bdev;
4282	b->bi_sector = r10_bio->devs[s/2].addr + rdev2->new_data_offset;
4283	b->bi_private = r10_bio;
4284	b->bi_end_io = end_reshape_write;
4285	b->bi_rw = WRITE;
4286	b->bi_flags &= ~(BIO_POOL_MASK - 1);
4287	b->bi_flags \|= 1 << BIO_UPTODATE;
4288	b->bi_next = blist;
4289	b->bi_vcnt = 0;
4290	b->bi_idx = 0;
4291	b->bi_size = 0;
4292	blist = b;
4293	}
4294
4295	/* Now add as many pages as possible to all of these bios. */
4296
4297	nr_sectors = 0;
4298	for (s = 0 ; s < max_sectors; s += PAGE_SIZE >> 9) {
4299	struct page *page = r10_bio->devs[0].bio->bi_io_vec[s/(PAGE_SIZE>>9)].bv_page;
4300	int len = (max_sectors - s) << 9;
4301	if (len > PAGE_SIZE)
4302	len = PAGE_SIZE;
4303	for (bio = blist; bio ; bio = bio->bi_next) {
4304	struct bio *bio2;
4305	if (bio_add_page(bio, page, len, 0))
4306	continue;
4307
4308	/* Didn't fit, must stop */
4309	for (bio2 = blist;
4310	bio2 && bio2 != bio;
4311	bio2 = bio2->bi_next) {
4312	/* Remove last page from this bio */
4313	bio2->bi_vcnt--;
4314	bio2->bi_size -= len;
4315	bio2->bi_flags &= ~(1<<BIO_SEG_VALID);
4316	}
4317	goto bio_full;
4318	}
4319	sector_nr += len >> 9;
4320	nr_sectors += len >> 9;
4321	}
4322	bio_full:
4323	r10_bio->sectors = nr_sectors;
4324
4325	/* Now submit the read */
4326	md_sync_acct(read_bio->bi_bdev, r10_bio->sectors);
4327	atomic_inc(&r10_bio->remaining);
4328	read_bio->bi_next = NULL;
4329	generic_make_request(read_bio);
4330	sector_nr += nr_sectors;
4331	sectors_done += nr_sectors;
4332	if (sector_nr <= last)
4333	goto read_more;
4334
4335	/* Now that we have done the whole section we can
4336	* update reshape_progress
4337	*/
4338	if (mddev->reshape_backwards)
4339	conf->reshape_progress -= sectors_done;
4340	else
4341	conf->reshape_progress += sectors_done;
4342
4343	return sectors_done;
4344	}
4345
4346	static void end_reshape_request(struct r10bio *r10_bio);
4347	static int handle_reshape_read_error(struct mddev *mddev,
4348	struct r10bio *r10_bio);
4349	static void reshape_request_write(struct mddev mddev, struct r10bio r10_bio)
4350	{
4351	/* Reshape read completed. Hopefully we have a block
4352	* to write out.
4353	* If we got a read error then we do sync 1-page reads from
4354	* elsewhere until we find the data - or give up.
4355	*/
4356	struct r10conf *conf = mddev->private;
4357	int s;
4358
4359	if (!test_bit(R10BIO_Uptodate, &r10_bio->state))
4360	if (handle_reshape_read_error(mddev, r10_bio) < 0) {
4361	/* Reshape has been aborted */
4362	md_done_sync(mddev, r10_bio->sectors, 0);
4363	return;
4364	}
4365
4366	/* We definitely have the data in the pages, schedule the
4367	* writes.
4368	*/
4369	atomic_set(&r10_bio->remaining, 1);
4370	for (s = 0; s < conf->copies*2; s++) {
4371	struct bio *b;
4372	int d = r10_bio->devs[s/2].devnum;
4373	struct md_rdev *rdev;
4374	if (s&1) {
4375	rdev = conf->mirrors[d].replacement;
4376	b = r10_bio->devs[s/2].repl_bio;
4377	} else {
4378	rdev = conf->mirrors[d].rdev;
4379	b = r10_bio->devs[s/2].bio;
4380	}
4381	if (!rdev \|\| test_bit(Faulty, &rdev->flags))
4382	continue;
4383	atomic_inc(&rdev->nr_pending);
4384	md_sync_acct(b->bi_bdev, r10_bio->sectors);
4385	atomic_inc(&r10_bio->remaining);
4386	b->bi_next = NULL;
4387	generic_make_request(b);
4388	}
4389	end_reshape_request(r10_bio);
4390	}
4391
4392	static void end_reshape(struct r10conf *conf)
4393	{
4394	if (test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery))
4395	return;
4396
4397	spin_lock_irq(&conf->device_lock);
4398	conf->prev = conf->geo;
4399	md_finish_reshape(conf->mddev);
4400	smp_wmb();
4401	conf->reshape_progress = MaxSector;
4402	spin_unlock_irq(&conf->device_lock);
4403
4404	/* read-ahead size must cover two whole stripes, which is
4405	* 2 * (datadisks) * chunksize where 'n' is the number of raid devices
4406	*/
4407	if (conf->mddev->queue) {
4408	int stripe = conf->geo.raid_disks *
4409	((conf->mddev->chunk_sectors << 9) / PAGE_SIZE);
4410	stripe /= conf->geo.near_copies;
4411	if (conf->mddev->queue->backing_dev_info.ra_pages < 2 * stripe)
4412	conf->mddev->queue->backing_dev_info.ra_pages = 2 * stripe;
4413	}
4414	conf->fullsync = 0;
4415	}
4416
4417
4418	static int handle_reshape_read_error(struct mddev *mddev,
4419	struct r10bio *r10_bio)
4420	{
4421	/* Use sync reads to get the blocks from somewhere else */
4422	int sectors = r10_bio->sectors;
4423	struct r10conf *conf = mddev->private;
4424	struct {
4425	struct r10bio r10_bio;
4426	struct r10dev devs[conf->copies];
4427	} on_stack;
4428	struct r10bio *r10b = &on_stack.r10_bio;
4429	int slot = 0;
4430	int idx = 0;
4431	struct bio_vec *bvec = r10_bio->master_bio->bi_io_vec;
4432
4433	r10b->sector = r10_bio->sector;
4434	__raid10_find_phys(&conf->prev, r10b);
4435
4436	while (sectors) {
4437	int s = sectors;
4438	int success = 0;
4439	int first_slot = slot;
4440
4441	if (s > (PAGE_SIZE >> 9))
4442	s = PAGE_SIZE >> 9;
4443
4444	while (!success) {
4445	int d = r10b->devs[slot].devnum;
4446	struct md_rdev *rdev = conf->mirrors[d].rdev;
4447	sector_t addr;
4448	if (rdev == NULL \|\|
4449	test_bit(Faulty, &rdev->flags) \|\|
4450	!test_bit(In_sync, &rdev->flags))
4451	goto failed;
4452
4453	addr = r10b->devs[slot].addr + idx * PAGE_SIZE;
4454	success = sync_page_io(rdev,
4455	addr,
4456	s << 9,
4457	bvec[idx].bv_page,
4458	READ, false);
4459	if (success)
4460	break;
4461	failed:
4462	slot++;
4463	if (slot >= conf->copies)
4464	slot = 0;
4465	if (slot == first_slot)
4466	break;
4467	}
4468	if (!success) {
4469	/* couldn't read this block, must give up */
4470	set_bit(MD_RECOVERY_INTR,
4471	&mddev->recovery);
4472	return -EIO;
4473	}
4474	sectors -= s;
4475	idx++;
4476	}
4477	return 0;
4478	}
4479
4480	static void end_reshape_write(struct bio *bio, int error)
4481	{
4482	int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
4483	struct r10bio *r10_bio = bio->bi_private;
4484	struct mddev *mddev = r10_bio->mddev;
4485	struct r10conf *conf = mddev->private;
4486	int d;
4487	int slot;
4488	int repl;
4489	struct md_rdev *rdev = NULL;
4490
4491	d = find_bio_disk(conf, r10_bio, bio, &slot, &repl);
4492	if (repl)
4493	rdev = conf->mirrors[d].replacement;
4494	if (!rdev) {
4495	smp_mb();
4496	rdev = conf->mirrors[d].rdev;
4497	}
4498
4499	if (!uptodate) {
4500	/* FIXME should record badblock */
4501	md_error(mddev, rdev);
4502	}
4503
4504	rdev_dec_pending(rdev, mddev);
4505	end_reshape_request(r10_bio);
4506	}
4507
4508	static void end_reshape_request(struct r10bio *r10_bio)
4509	{
4510	if (!atomic_dec_and_test(&r10_bio->remaining))
4511	return;
4512	md_done_sync(r10_bio->mddev, r10_bio->sectors, 1);
4513	bio_put(r10_bio->master_bio);
4514	put_buf(r10_bio);
4515	}
4516
4517	static void raid10_finish_reshape(struct mddev *mddev)
4518	{
4519	struct r10conf *conf = mddev->private;
4520
4521	if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
4522	return;
4523
4524	if (mddev->delta_disks > 0) {
4525	sector_t size = raid10_size(mddev, 0, 0);
4526	md_set_array_sectors(mddev, size);
4527	if (mddev->recovery_cp > mddev->resync_max_sectors) {
4528	mddev->recovery_cp = mddev->resync_max_sectors;
4529	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
4530	}
4531	mddev->resync_max_sectors = size;
4532	set_capacity(mddev->gendisk, mddev->array_sectors);
4533	revalidate_disk(mddev->gendisk);
4534	} else {
4535	int d;
4536	for (d = conf->geo.raid_disks ;
4537	d < conf->geo.raid_disks - mddev->delta_disks;
4538	d++) {
4539	struct md_rdev *rdev = conf->mirrors[d].rdev;
4540	if (rdev)
4541	clear_bit(In_sync, &rdev->flags);
4542	rdev = conf->mirrors[d].replacement;
4543	if (rdev)
4544	clear_bit(In_sync, &rdev->flags);
4545	}
4546	}
4547	mddev->layout = mddev->new_layout;
4548	mddev->chunk_sectors = 1 << conf->geo.chunk_shift;
4549	mddev->reshape_position = MaxSector;
4550	mddev->delta_disks = 0;
4551	mddev->reshape_backwards = 0;
4552	}
4553
4554	static struct md_personality raid10_personality =
4555	{
4556	.name = "raid10",
4557	.level = 10,
4558	.owner = THIS_MODULE,
4559	.make_request = make_request,
4560	.run = run,
4561	.stop = stop,
4562	.status = status,
4563	.error_handler = error,
4564	.hot_add_disk = raid10_add_disk,
4565	.hot_remove_disk= raid10_remove_disk,
4566	.spare_active = raid10_spare_active,
4567	.sync_request = sync_request,
4568	.quiesce = raid10_quiesce,
4569	.size = raid10_size,
4570	.resize = raid10_resize,
4571	.takeover = raid10_takeover,
4572	.check_reshape = raid10_check_reshape,
4573	.start_reshape = raid10_start_reshape,
4574	.finish_reshape = raid10_finish_reshape,
4575	};
4576
4577	static int __init raid_init(void)
4578	{
4579	return register_md_personality(&raid10_personality);
4580	}
4581
4582	static void raid_exit(void)
4583	{
4584	unregister_md_personality(&raid10_personality);
4585	}
4586
4587	module_init(raid_init);
4588	module_exit(raid_exit);
4589	MODULE_LICENSE("GPL");
4590	MODULE_DESCRIPTION("RAID10 (striped mirror) personality for MD");
4591	MODULE_ALIAS("md-personality-9"); /* RAID10 */
4592	MODULE_ALIAS("md-raid10");
4593	MODULE_ALIAS("md-level-10");
4594
4595	module_param(max_queued_requests, int, S_IRUGO\|S_IWUSR);
4596

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