Merge tag 'kvmgt-vfio-mdev-for-v4.10-rc1' of git://github.com/01org/gvt-linux
[linux-2.6-microblaze.git] / 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 <trace/events/block.h>
29 #include "md.h"
30 #include "raid10.h"
31 #include "raid0.h"
32 #include "bitmap.h"
33
34 /*
35  * RAID10 provides a combination of RAID0 and RAID1 functionality.
36  * The layout of data is defined by
37  *    chunk_size
38  *    raid_disks
39  *    near_copies (stored in low byte of layout)
40  *    far_copies (stored in second byte of layout)
41  *    far_offset (stored in bit 16 of layout )
42  *    use_far_sets (stored in bit 17 of layout )
43  *    use_far_sets_bugfixed (stored in bit 18 of layout )
44  *
45  * The data to be stored is divided into chunks using chunksize.  Each device
46  * is divided into far_copies sections.   In each section, chunks are laid out
47  * in a style similar to raid0, but near_copies copies of each chunk is stored
48  * (each on a different drive).  The starting device for each section is offset
49  * near_copies from the starting device of the previous section.  Thus there
50  * are (near_copies * far_copies) of each chunk, and each is on a different
51  * drive.  near_copies and far_copies must be at least one, and their product
52  * is at most raid_disks.
53  *
54  * If far_offset is true, then the far_copies are handled a bit differently.
55  * The copies are still in different stripes, but instead of being very far
56  * apart on disk, there are adjacent stripes.
57  *
58  * The far and offset algorithms are handled slightly differently if
59  * 'use_far_sets' is true.  In this case, the array's devices are grouped into
60  * sets that are (near_copies * far_copies) in size.  The far copied stripes
61  * are still shifted by 'near_copies' devices, but this shifting stays confined
62  * to the set rather than the entire array.  This is done to improve the number
63  * of device combinations that can fail without causing the array to fail.
64  * Example 'far' algorithm w/o 'use_far_sets' (each letter represents a chunk
65  * on a device):
66  *    A B C D    A B C D E
67  *      ...         ...
68  *    D A B C    E A B C D
69  * Example 'far' algorithm w/ 'use_far_sets' enabled (sets illustrated w/ []'s):
70  *    [A B] [C D]    [A B] [C D E]
71  *    |...| |...|    |...| | ... |
72  *    [B A] [D C]    [B A] [E C D]
73  */
74
75 /*
76  * Number of guaranteed r10bios in case of extreme VM load:
77  */
78 #define NR_RAID10_BIOS 256
79
80 /* when we get a read error on a read-only array, we redirect to another
81  * device without failing the first device, or trying to over-write to
82  * correct the read error.  To keep track of bad blocks on a per-bio
83  * level, we store IO_BLOCKED in the appropriate 'bios' pointer
84  */
85 #define IO_BLOCKED ((struct bio *)1)
86 /* When we successfully write to a known bad-block, we need to remove the
87  * bad-block marking which must be done from process context.  So we record
88  * the success by setting devs[n].bio to IO_MADE_GOOD
89  */
90 #define IO_MADE_GOOD ((struct bio *)2)
91
92 #define BIO_SPECIAL(bio) ((unsigned long)bio <= 2)
93
94 /* When there are this many requests queued to be written by
95  * the raid10 thread, we become 'congested' to provide back-pressure
96  * for writeback.
97  */
98 static int max_queued_requests = 1024;
99
100 static void allow_barrier(struct r10conf *conf);
101 static void lower_barrier(struct r10conf *conf);
102 static int _enough(struct r10conf *conf, int previous, int ignore);
103 static int enough(struct r10conf *conf, int ignore);
104 static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr,
105                                 int *skipped);
106 static void reshape_request_write(struct mddev *mddev, struct r10bio *r10_bio);
107 static void end_reshape_write(struct bio *bio);
108 static void end_reshape(struct r10conf *conf);
109
110 #define raid10_log(md, fmt, args...)                            \
111         do { if ((md)->queue) blk_add_trace_msg((md)->queue, "raid10 " fmt, ##args); } while (0)
112
113 static void * r10bio_pool_alloc(gfp_t gfp_flags, void *data)
114 {
115         struct r10conf *conf = data;
116         int size = offsetof(struct r10bio, devs[conf->copies]);
117
118         /* allocate a r10bio with room for raid_disks entries in the
119          * bios array */
120         return kzalloc(size, gfp_flags);
121 }
122
123 static void r10bio_pool_free(void *r10_bio, void *data)
124 {
125         kfree(r10_bio);
126 }
127
128 /* Maximum size of each resync request */
129 #define RESYNC_BLOCK_SIZE (64*1024)
130 #define RESYNC_PAGES ((RESYNC_BLOCK_SIZE + PAGE_SIZE-1) / PAGE_SIZE)
131 /* amount of memory to reserve for resync requests */
132 #define RESYNC_WINDOW (1024*1024)
133 /* maximum number of concurrent requests, memory permitting */
134 #define RESYNC_DEPTH (32*1024*1024/RESYNC_BLOCK_SIZE)
135
136 /*
137  * When performing a resync, we need to read and compare, so
138  * we need as many pages are there are copies.
139  * When performing a recovery, we need 2 bios, one for read,
140  * one for write (we recover only one drive per r10buf)
141  *
142  */
143 static void * r10buf_pool_alloc(gfp_t gfp_flags, void *data)
144 {
145         struct r10conf *conf = data;
146         struct page *page;
147         struct r10bio *r10_bio;
148         struct bio *bio;
149         int i, j;
150         int nalloc;
151
152         r10_bio = r10bio_pool_alloc(gfp_flags, conf);
153         if (!r10_bio)
154                 return NULL;
155
156         if (test_bit(MD_RECOVERY_SYNC, &conf->mddev->recovery) ||
157             test_bit(MD_RECOVERY_RESHAPE, &conf->mddev->recovery))
158                 nalloc = conf->copies; /* resync */
159         else
160                 nalloc = 2; /* recovery */
161
162         /*
163          * Allocate bios.
164          */
165         for (j = nalloc ; j-- ; ) {
166                 bio = bio_kmalloc(gfp_flags, RESYNC_PAGES);
167                 if (!bio)
168                         goto out_free_bio;
169                 r10_bio->devs[j].bio = bio;
170                 if (!conf->have_replacement)
171                         continue;
172                 bio = bio_kmalloc(gfp_flags, RESYNC_PAGES);
173                 if (!bio)
174                         goto out_free_bio;
175                 r10_bio->devs[j].repl_bio = bio;
176         }
177         /*
178          * Allocate RESYNC_PAGES data pages and attach them
179          * where needed.
180          */
181         for (j = 0 ; j < nalloc; j++) {
182                 struct bio *rbio = r10_bio->devs[j].repl_bio;
183                 bio = r10_bio->devs[j].bio;
184                 for (i = 0; i < RESYNC_PAGES; i++) {
185                         if (j > 0 && !test_bit(MD_RECOVERY_SYNC,
186                                                &conf->mddev->recovery)) {
187                                 /* we can share bv_page's during recovery
188                                  * and reshape */
189                                 struct bio *rbio = r10_bio->devs[0].bio;
190                                 page = rbio->bi_io_vec[i].bv_page;
191                                 get_page(page);
192                         } else
193                                 page = alloc_page(gfp_flags);
194                         if (unlikely(!page))
195                                 goto out_free_pages;
196
197                         bio->bi_io_vec[i].bv_page = page;
198                         if (rbio)
199                                 rbio->bi_io_vec[i].bv_page = page;
200                 }
201         }
202
203         return r10_bio;
204
205 out_free_pages:
206         for ( ; i > 0 ; i--)
207                 safe_put_page(bio->bi_io_vec[i-1].bv_page);
208         while (j--)
209                 for (i = 0; i < RESYNC_PAGES ; i++)
210                         safe_put_page(r10_bio->devs[j].bio->bi_io_vec[i].bv_page);
211         j = 0;
212 out_free_bio:
213         for ( ; j < nalloc; j++) {
214                 if (r10_bio->devs[j].bio)
215                         bio_put(r10_bio->devs[j].bio);
216                 if (r10_bio->devs[j].repl_bio)
217                         bio_put(r10_bio->devs[j].repl_bio);
218         }
219         r10bio_pool_free(r10_bio, conf);
220         return NULL;
221 }
222
223 static void r10buf_pool_free(void *__r10_bio, void *data)
224 {
225         int i;
226         struct r10conf *conf = data;
227         struct r10bio *r10bio = __r10_bio;
228         int j;
229
230         for (j=0; j < conf->copies; j++) {
231                 struct bio *bio = r10bio->devs[j].bio;
232                 if (bio) {
233                         for (i = 0; i < RESYNC_PAGES; i++) {
234                                 safe_put_page(bio->bi_io_vec[i].bv_page);
235                                 bio->bi_io_vec[i].bv_page = NULL;
236                         }
237                         bio_put(bio);
238                 }
239                 bio = r10bio->devs[j].repl_bio;
240                 if (bio)
241                         bio_put(bio);
242         }
243         r10bio_pool_free(r10bio, conf);
244 }
245
246 static void put_all_bios(struct r10conf *conf, struct r10bio *r10_bio)
247 {
248         int i;
249
250         for (i = 0; i < conf->copies; i++) {
251                 struct bio **bio = & r10_bio->devs[i].bio;
252                 if (!BIO_SPECIAL(*bio))
253                         bio_put(*bio);
254                 *bio = NULL;
255                 bio = &r10_bio->devs[i].repl_bio;
256                 if (r10_bio->read_slot < 0 && !BIO_SPECIAL(*bio))
257                         bio_put(*bio);
258                 *bio = NULL;
259         }
260 }
261
262 static void free_r10bio(struct r10bio *r10_bio)
263 {
264         struct r10conf *conf = r10_bio->mddev->private;
265
266         put_all_bios(conf, r10_bio);
267         mempool_free(r10_bio, conf->r10bio_pool);
268 }
269
270 static void put_buf(struct r10bio *r10_bio)
271 {
272         struct r10conf *conf = r10_bio->mddev->private;
273
274         mempool_free(r10_bio, conf->r10buf_pool);
275
276         lower_barrier(conf);
277 }
278
279 static void reschedule_retry(struct r10bio *r10_bio)
280 {
281         unsigned long flags;
282         struct mddev *mddev = r10_bio->mddev;
283         struct r10conf *conf = mddev->private;
284
285         spin_lock_irqsave(&conf->device_lock, flags);
286         list_add(&r10_bio->retry_list, &conf->retry_list);
287         conf->nr_queued ++;
288         spin_unlock_irqrestore(&conf->device_lock, flags);
289
290         /* wake up frozen array... */
291         wake_up(&conf->wait_barrier);
292
293         md_wakeup_thread(mddev->thread);
294 }
295
296 /*
297  * raid_end_bio_io() is called when we have finished servicing a mirrored
298  * operation and are ready to return a success/failure code to the buffer
299  * cache layer.
300  */
301 static void raid_end_bio_io(struct r10bio *r10_bio)
302 {
303         struct bio *bio = r10_bio->master_bio;
304         int done;
305         struct r10conf *conf = r10_bio->mddev->private;
306
307         if (bio->bi_phys_segments) {
308                 unsigned long flags;
309                 spin_lock_irqsave(&conf->device_lock, flags);
310                 bio->bi_phys_segments--;
311                 done = (bio->bi_phys_segments == 0);
312                 spin_unlock_irqrestore(&conf->device_lock, flags);
313         } else
314                 done = 1;
315         if (!test_bit(R10BIO_Uptodate, &r10_bio->state))
316                 bio->bi_error = -EIO;
317         if (done) {
318                 bio_endio(bio);
319                 /*
320                  * Wake up any possible resync thread that waits for the device
321                  * to go idle.
322                  */
323                 allow_barrier(conf);
324         }
325         free_r10bio(r10_bio);
326 }
327
328 /*
329  * Update disk head position estimator based on IRQ completion info.
330  */
331 static inline void update_head_pos(int slot, struct r10bio *r10_bio)
332 {
333         struct r10conf *conf = r10_bio->mddev->private;
334
335         conf->mirrors[r10_bio->devs[slot].devnum].head_position =
336                 r10_bio->devs[slot].addr + (r10_bio->sectors);
337 }
338
339 /*
340  * Find the disk number which triggered given bio
341  */
342 static int find_bio_disk(struct r10conf *conf, struct r10bio *r10_bio,
343                          struct bio *bio, int *slotp, int *replp)
344 {
345         int slot;
346         int repl = 0;
347
348         for (slot = 0; slot < conf->copies; slot++) {
349                 if (r10_bio->devs[slot].bio == bio)
350                         break;
351                 if (r10_bio->devs[slot].repl_bio == bio) {
352                         repl = 1;
353                         break;
354                 }
355         }
356
357         BUG_ON(slot == conf->copies);
358         update_head_pos(slot, r10_bio);
359
360         if (slotp)
361                 *slotp = slot;
362         if (replp)
363                 *replp = repl;
364         return r10_bio->devs[slot].devnum;
365 }
366
367 static void raid10_end_read_request(struct bio *bio)
368 {
369         int uptodate = !bio->bi_error;
370         struct r10bio *r10_bio = bio->bi_private;
371         int slot, dev;
372         struct md_rdev *rdev;
373         struct r10conf *conf = r10_bio->mddev->private;
374
375         slot = r10_bio->read_slot;
376         dev = r10_bio->devs[slot].devnum;
377         rdev = r10_bio->devs[slot].rdev;
378         /*
379          * this branch is our 'one mirror IO has finished' event handler:
380          */
381         update_head_pos(slot, r10_bio);
382
383         if (uptodate) {
384                 /*
385                  * Set R10BIO_Uptodate in our master bio, so that
386                  * we will return a good error code to the higher
387                  * levels even if IO on some other mirrored buffer fails.
388                  *
389                  * The 'master' represents the composite IO operation to
390                  * user-side. So if something waits for IO, then it will
391                  * wait for the 'master' bio.
392                  */
393                 set_bit(R10BIO_Uptodate, &r10_bio->state);
394         } else {
395                 /* If all other devices that store this block have
396                  * failed, we want to return the error upwards rather
397                  * than fail the last device.  Here we redefine
398                  * "uptodate" to mean "Don't want to retry"
399                  */
400                 if (!_enough(conf, test_bit(R10BIO_Previous, &r10_bio->state),
401                              rdev->raid_disk))
402                         uptodate = 1;
403         }
404         if (uptodate) {
405                 raid_end_bio_io(r10_bio);
406                 rdev_dec_pending(rdev, conf->mddev);
407         } else {
408                 /*
409                  * oops, read error - keep the refcount on the rdev
410                  */
411                 char b[BDEVNAME_SIZE];
412                 pr_err_ratelimited("md/raid10:%s: %s: rescheduling sector %llu\n",
413                                    mdname(conf->mddev),
414                                    bdevname(rdev->bdev, b),
415                                    (unsigned long long)r10_bio->sector);
416                 set_bit(R10BIO_ReadError, &r10_bio->state);
417                 reschedule_retry(r10_bio);
418         }
419 }
420
421 static void close_write(struct r10bio *r10_bio)
422 {
423         /* clear the bitmap if all writes complete successfully */
424         bitmap_endwrite(r10_bio->mddev->bitmap, r10_bio->sector,
425                         r10_bio->sectors,
426                         !test_bit(R10BIO_Degraded, &r10_bio->state),
427                         0);
428         md_write_end(r10_bio->mddev);
429 }
430
431 static void one_write_done(struct r10bio *r10_bio)
432 {
433         if (atomic_dec_and_test(&r10_bio->remaining)) {
434                 if (test_bit(R10BIO_WriteError, &r10_bio->state))
435                         reschedule_retry(r10_bio);
436                 else {
437                         close_write(r10_bio);
438                         if (test_bit(R10BIO_MadeGood, &r10_bio->state))
439                                 reschedule_retry(r10_bio);
440                         else
441                                 raid_end_bio_io(r10_bio);
442                 }
443         }
444 }
445
446 static void raid10_end_write_request(struct bio *bio)
447 {
448         struct r10bio *r10_bio = bio->bi_private;
449         int dev;
450         int dec_rdev = 1;
451         struct r10conf *conf = r10_bio->mddev->private;
452         int slot, repl;
453         struct md_rdev *rdev = NULL;
454         struct bio *to_put = NULL;
455         bool discard_error;
456
457         discard_error = bio->bi_error && bio_op(bio) == REQ_OP_DISCARD;
458
459         dev = find_bio_disk(conf, r10_bio, bio, &slot, &repl);
460
461         if (repl)
462                 rdev = conf->mirrors[dev].replacement;
463         if (!rdev) {
464                 smp_rmb();
465                 repl = 0;
466                 rdev = conf->mirrors[dev].rdev;
467         }
468         /*
469          * this branch is our 'one mirror IO has finished' event handler:
470          */
471         if (bio->bi_error && !discard_error) {
472                 if (repl)
473                         /* Never record new bad blocks to replacement,
474                          * just fail it.
475                          */
476                         md_error(rdev->mddev, rdev);
477                 else {
478                         set_bit(WriteErrorSeen, &rdev->flags);
479                         if (!test_and_set_bit(WantReplacement, &rdev->flags))
480                                 set_bit(MD_RECOVERY_NEEDED,
481                                         &rdev->mddev->recovery);
482
483                         dec_rdev = 0;
484                         if (test_bit(FailFast, &rdev->flags) &&
485                             (bio->bi_opf & MD_FAILFAST)) {
486                                 md_error(rdev->mddev, rdev);
487                                 if (!test_bit(Faulty, &rdev->flags))
488                                         /* This is the only remaining device,
489                                          * We need to retry the write without
490                                          * FailFast
491                                          */
492                                         set_bit(R10BIO_WriteError, &r10_bio->state);
493                                 else {
494                                         r10_bio->devs[slot].bio = NULL;
495                                         to_put = bio;
496                                         dec_rdev = 1;
497                                 }
498                         } else
499                                 set_bit(R10BIO_WriteError, &r10_bio->state);
500                 }
501         } else {
502                 /*
503                  * Set R10BIO_Uptodate in our master bio, so that
504                  * we will return a good error code for to the higher
505                  * levels even if IO on some other mirrored buffer fails.
506                  *
507                  * The 'master' represents the composite IO operation to
508                  * user-side. So if something waits for IO, then it will
509                  * wait for the 'master' bio.
510                  */
511                 sector_t first_bad;
512                 int bad_sectors;
513
514                 /*
515                  * Do not set R10BIO_Uptodate if the current device is
516                  * rebuilding or Faulty. This is because we cannot use
517                  * such device for properly reading the data back (we could
518                  * potentially use it, if the current write would have felt
519                  * before rdev->recovery_offset, but for simplicity we don't
520                  * check this here.
521                  */
522                 if (test_bit(In_sync, &rdev->flags) &&
523                     !test_bit(Faulty, &rdev->flags))
524                         set_bit(R10BIO_Uptodate, &r10_bio->state);
525
526                 /* Maybe we can clear some bad blocks. */
527                 if (is_badblock(rdev,
528                                 r10_bio->devs[slot].addr,
529                                 r10_bio->sectors,
530                                 &first_bad, &bad_sectors) && !discard_error) {
531                         bio_put(bio);
532                         if (repl)
533                                 r10_bio->devs[slot].repl_bio = IO_MADE_GOOD;
534                         else
535                                 r10_bio->devs[slot].bio = IO_MADE_GOOD;
536                         dec_rdev = 0;
537                         set_bit(R10BIO_MadeGood, &r10_bio->state);
538                 }
539         }
540
541         /*
542          *
543          * Let's see if all mirrored write operations have finished
544          * already.
545          */
546         one_write_done(r10_bio);
547         if (dec_rdev)
548                 rdev_dec_pending(rdev, conf->mddev);
549         if (to_put)
550                 bio_put(to_put);
551 }
552
553 /*
554  * RAID10 layout manager
555  * As well as the chunksize and raid_disks count, there are two
556  * parameters: near_copies and far_copies.
557  * near_copies * far_copies must be <= raid_disks.
558  * Normally one of these will be 1.
559  * If both are 1, we get raid0.
560  * If near_copies == raid_disks, we get raid1.
561  *
562  * Chunks are laid out in raid0 style with near_copies copies of the
563  * first chunk, followed by near_copies copies of the next chunk and
564  * so on.
565  * If far_copies > 1, then after 1/far_copies of the array has been assigned
566  * as described above, we start again with a device offset of near_copies.
567  * So we effectively have another copy of the whole array further down all
568  * the drives, but with blocks on different drives.
569  * With this layout, and block is never stored twice on the one device.
570  *
571  * raid10_find_phys finds the sector offset of a given virtual sector
572  * on each device that it is on.
573  *
574  * raid10_find_virt does the reverse mapping, from a device and a
575  * sector offset to a virtual address
576  */
577
578 static void __raid10_find_phys(struct geom *geo, struct r10bio *r10bio)
579 {
580         int n,f;
581         sector_t sector;
582         sector_t chunk;
583         sector_t stripe;
584         int dev;
585         int slot = 0;
586         int last_far_set_start, last_far_set_size;
587
588         last_far_set_start = (geo->raid_disks / geo->far_set_size) - 1;
589         last_far_set_start *= geo->far_set_size;
590
591         last_far_set_size = geo->far_set_size;
592         last_far_set_size += (geo->raid_disks % geo->far_set_size);
593
594         /* now calculate first sector/dev */
595         chunk = r10bio->sector >> geo->chunk_shift;
596         sector = r10bio->sector & geo->chunk_mask;
597
598         chunk *= geo->near_copies;
599         stripe = chunk;
600         dev = sector_div(stripe, geo->raid_disks);
601         if (geo->far_offset)
602                 stripe *= geo->far_copies;
603
604         sector += stripe << geo->chunk_shift;
605
606         /* and calculate all the others */
607         for (n = 0; n < geo->near_copies; n++) {
608                 int d = dev;
609                 int set;
610                 sector_t s = sector;
611                 r10bio->devs[slot].devnum = d;
612                 r10bio->devs[slot].addr = s;
613                 slot++;
614
615                 for (f = 1; f < geo->far_copies; f++) {
616                         set = d / geo->far_set_size;
617                         d += geo->near_copies;
618
619                         if ((geo->raid_disks % geo->far_set_size) &&
620                             (d > last_far_set_start)) {
621                                 d -= last_far_set_start;
622                                 d %= last_far_set_size;
623                                 d += last_far_set_start;
624                         } else {
625                                 d %= geo->far_set_size;
626                                 d += geo->far_set_size * set;
627                         }
628                         s += geo->stride;
629                         r10bio->devs[slot].devnum = d;
630                         r10bio->devs[slot].addr = s;
631                         slot++;
632                 }
633                 dev++;
634                 if (dev >= geo->raid_disks) {
635                         dev = 0;
636                         sector += (geo->chunk_mask + 1);
637                 }
638         }
639 }
640
641 static void raid10_find_phys(struct r10conf *conf, struct r10bio *r10bio)
642 {
643         struct geom *geo = &conf->geo;
644
645         if (conf->reshape_progress != MaxSector &&
646             ((r10bio->sector >= conf->reshape_progress) !=
647              conf->mddev->reshape_backwards)) {
648                 set_bit(R10BIO_Previous, &r10bio->state);
649                 geo = &conf->prev;
650         } else
651                 clear_bit(R10BIO_Previous, &r10bio->state);
652
653         __raid10_find_phys(geo, r10bio);
654 }
655
656 static sector_t raid10_find_virt(struct r10conf *conf, sector_t sector, int dev)
657 {
658         sector_t offset, chunk, vchunk;
659         /* Never use conf->prev as this is only called during resync
660          * or recovery, so reshape isn't happening
661          */
662         struct geom *geo = &conf->geo;
663         int far_set_start = (dev / geo->far_set_size) * geo->far_set_size;
664         int far_set_size = geo->far_set_size;
665         int last_far_set_start;
666
667         if (geo->raid_disks % geo->far_set_size) {
668                 last_far_set_start = (geo->raid_disks / geo->far_set_size) - 1;
669                 last_far_set_start *= geo->far_set_size;
670
671                 if (dev >= last_far_set_start) {
672                         far_set_size = geo->far_set_size;
673                         far_set_size += (geo->raid_disks % geo->far_set_size);
674                         far_set_start = last_far_set_start;
675                 }
676         }
677
678         offset = sector & geo->chunk_mask;
679         if (geo->far_offset) {
680                 int fc;
681                 chunk = sector >> geo->chunk_shift;
682                 fc = sector_div(chunk, geo->far_copies);
683                 dev -= fc * geo->near_copies;
684                 if (dev < far_set_start)
685                         dev += far_set_size;
686         } else {
687                 while (sector >= geo->stride) {
688                         sector -= geo->stride;
689                         if (dev < (geo->near_copies + far_set_start))
690                                 dev += far_set_size - geo->near_copies;
691                         else
692                                 dev -= geo->near_copies;
693                 }
694                 chunk = sector >> geo->chunk_shift;
695         }
696         vchunk = chunk * geo->raid_disks + dev;
697         sector_div(vchunk, geo->near_copies);
698         return (vchunk << geo->chunk_shift) + offset;
699 }
700
701 /*
702  * This routine returns the disk from which the requested read should
703  * be done. There is a per-array 'next expected sequential IO' sector
704  * number - if this matches on the next IO then we use the last disk.
705  * There is also a per-disk 'last know head position' sector that is
706  * maintained from IRQ contexts, both the normal and the resync IO
707  * completion handlers update this position correctly. If there is no
708  * perfect sequential match then we pick the disk whose head is closest.
709  *
710  * If there are 2 mirrors in the same 2 devices, performance degrades
711  * because position is mirror, not device based.
712  *
713  * The rdev for the device selected will have nr_pending incremented.
714  */
715
716 /*
717  * FIXME: possibly should rethink readbalancing and do it differently
718  * depending on near_copies / far_copies geometry.
719  */
720 static struct md_rdev *read_balance(struct r10conf *conf,
721                                     struct r10bio *r10_bio,
722                                     int *max_sectors)
723 {
724         const sector_t this_sector = r10_bio->sector;
725         int disk, slot;
726         int sectors = r10_bio->sectors;
727         int best_good_sectors;
728         sector_t new_distance, best_dist;
729         struct md_rdev *best_rdev, *rdev = NULL;
730         int do_balance;
731         int best_slot;
732         struct geom *geo = &conf->geo;
733
734         raid10_find_phys(conf, r10_bio);
735         rcu_read_lock();
736         sectors = r10_bio->sectors;
737         best_slot = -1;
738         best_rdev = NULL;
739         best_dist = MaxSector;
740         best_good_sectors = 0;
741         do_balance = 1;
742         clear_bit(R10BIO_FailFast, &r10_bio->state);
743         /*
744          * Check if we can balance. We can balance on the whole
745          * device if no resync is going on (recovery is ok), or below
746          * the resync window. We take the first readable disk when
747          * above the resync window.
748          */
749         if (conf->mddev->recovery_cp < MaxSector
750             && (this_sector + sectors >= conf->next_resync))
751                 do_balance = 0;
752
753         for (slot = 0; slot < conf->copies ; slot++) {
754                 sector_t first_bad;
755                 int bad_sectors;
756                 sector_t dev_sector;
757
758                 if (r10_bio->devs[slot].bio == IO_BLOCKED)
759                         continue;
760                 disk = r10_bio->devs[slot].devnum;
761                 rdev = rcu_dereference(conf->mirrors[disk].replacement);
762                 if (rdev == NULL || test_bit(Faulty, &rdev->flags) ||
763                     r10_bio->devs[slot].addr + sectors > rdev->recovery_offset)
764                         rdev = rcu_dereference(conf->mirrors[disk].rdev);
765                 if (rdev == NULL ||
766                     test_bit(Faulty, &rdev->flags))
767                         continue;
768                 if (!test_bit(In_sync, &rdev->flags) &&
769                     r10_bio->devs[slot].addr + sectors > rdev->recovery_offset)
770                         continue;
771
772                 dev_sector = r10_bio->devs[slot].addr;
773                 if (is_badblock(rdev, dev_sector, sectors,
774                                 &first_bad, &bad_sectors)) {
775                         if (best_dist < MaxSector)
776                                 /* Already have a better slot */
777                                 continue;
778                         if (first_bad <= dev_sector) {
779                                 /* Cannot read here.  If this is the
780                                  * 'primary' device, then we must not read
781                                  * beyond 'bad_sectors' from another device.
782                                  */
783                                 bad_sectors -= (dev_sector - first_bad);
784                                 if (!do_balance && sectors > bad_sectors)
785                                         sectors = bad_sectors;
786                                 if (best_good_sectors > sectors)
787                                         best_good_sectors = sectors;
788                         } else {
789                                 sector_t good_sectors =
790                                         first_bad - dev_sector;
791                                 if (good_sectors > best_good_sectors) {
792                                         best_good_sectors = good_sectors;
793                                         best_slot = slot;
794                                         best_rdev = rdev;
795                                 }
796                                 if (!do_balance)
797                                         /* Must read from here */
798                                         break;
799                         }
800                         continue;
801                 } else
802                         best_good_sectors = sectors;
803
804                 if (!do_balance)
805                         break;
806
807                 if (best_slot >= 0)
808                         /* At least 2 disks to choose from so failfast is OK */
809                         set_bit(R10BIO_FailFast, &r10_bio->state);
810                 /* This optimisation is debatable, and completely destroys
811                  * sequential read speed for 'far copies' arrays.  So only
812                  * keep it for 'near' arrays, and review those later.
813                  */
814                 if (geo->near_copies > 1 && !atomic_read(&rdev->nr_pending))
815                         new_distance = 0;
816
817                 /* for far > 1 always use the lowest address */
818                 else if (geo->far_copies > 1)
819                         new_distance = r10_bio->devs[slot].addr;
820                 else
821                         new_distance = abs(r10_bio->devs[slot].addr -
822                                            conf->mirrors[disk].head_position);
823                 if (new_distance < best_dist) {
824                         best_dist = new_distance;
825                         best_slot = slot;
826                         best_rdev = rdev;
827                 }
828         }
829         if (slot >= conf->copies) {
830                 slot = best_slot;
831                 rdev = best_rdev;
832         }
833
834         if (slot >= 0) {
835                 atomic_inc(&rdev->nr_pending);
836                 r10_bio->read_slot = slot;
837         } else
838                 rdev = NULL;
839         rcu_read_unlock();
840         *max_sectors = best_good_sectors;
841
842         return rdev;
843 }
844
845 static int raid10_congested(struct mddev *mddev, int bits)
846 {
847         struct r10conf *conf = mddev->private;
848         int i, ret = 0;
849
850         if ((bits & (1 << WB_async_congested)) &&
851             conf->pending_count >= max_queued_requests)
852                 return 1;
853
854         rcu_read_lock();
855         for (i = 0;
856              (i < conf->geo.raid_disks || i < conf->prev.raid_disks)
857                      && ret == 0;
858              i++) {
859                 struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
860                 if (rdev && !test_bit(Faulty, &rdev->flags)) {
861                         struct request_queue *q = bdev_get_queue(rdev->bdev);
862
863                         ret |= bdi_congested(&q->backing_dev_info, bits);
864                 }
865         }
866         rcu_read_unlock();
867         return ret;
868 }
869
870 static void flush_pending_writes(struct r10conf *conf)
871 {
872         /* Any writes that have been queued but are awaiting
873          * bitmap updates get flushed here.
874          */
875         spin_lock_irq(&conf->device_lock);
876
877         if (conf->pending_bio_list.head) {
878                 struct bio *bio;
879                 bio = bio_list_get(&conf->pending_bio_list);
880                 conf->pending_count = 0;
881                 spin_unlock_irq(&conf->device_lock);
882                 /* flush any pending bitmap writes to disk
883                  * before proceeding w/ I/O */
884                 bitmap_unplug(conf->mddev->bitmap);
885                 wake_up(&conf->wait_barrier);
886
887                 while (bio) { /* submit pending writes */
888                         struct bio *next = bio->bi_next;
889                         struct md_rdev *rdev = (void*)bio->bi_bdev;
890                         bio->bi_next = NULL;
891                         bio->bi_bdev = rdev->bdev;
892                         if (test_bit(Faulty, &rdev->flags)) {
893                                 bio->bi_error = -EIO;
894                                 bio_endio(bio);
895                         } else if (unlikely((bio_op(bio) ==  REQ_OP_DISCARD) &&
896                                             !blk_queue_discard(bdev_get_queue(bio->bi_bdev))))
897                                 /* Just ignore it */
898                                 bio_endio(bio);
899                         else
900                                 generic_make_request(bio);
901                         bio = next;
902                 }
903         } else
904                 spin_unlock_irq(&conf->device_lock);
905 }
906
907 /* Barriers....
908  * Sometimes we need to suspend IO while we do something else,
909  * either some resync/recovery, or reconfigure the array.
910  * To do this we raise a 'barrier'.
911  * The 'barrier' is a counter that can be raised multiple times
912  * to count how many activities are happening which preclude
913  * normal IO.
914  * We can only raise the barrier if there is no pending IO.
915  * i.e. if nr_pending == 0.
916  * We choose only to raise the barrier if no-one is waiting for the
917  * barrier to go down.  This means that as soon as an IO request
918  * is ready, no other operations which require a barrier will start
919  * until the IO request has had a chance.
920  *
921  * So: regular IO calls 'wait_barrier'.  When that returns there
922  *    is no backgroup IO happening,  It must arrange to call
923  *    allow_barrier when it has finished its IO.
924  * backgroup IO calls must call raise_barrier.  Once that returns
925  *    there is no normal IO happeing.  It must arrange to call
926  *    lower_barrier when the particular background IO completes.
927  */
928
929 static void raise_barrier(struct r10conf *conf, int force)
930 {
931         BUG_ON(force && !conf->barrier);
932         spin_lock_irq(&conf->resync_lock);
933
934         /* Wait until no block IO is waiting (unless 'force') */
935         wait_event_lock_irq(conf->wait_barrier, force || !conf->nr_waiting,
936                             conf->resync_lock);
937
938         /* block any new IO from starting */
939         conf->barrier++;
940
941         /* Now wait for all pending IO to complete */
942         wait_event_lock_irq(conf->wait_barrier,
943                             !atomic_read(&conf->nr_pending) && conf->barrier < RESYNC_DEPTH,
944                             conf->resync_lock);
945
946         spin_unlock_irq(&conf->resync_lock);
947 }
948
949 static void lower_barrier(struct r10conf *conf)
950 {
951         unsigned long flags;
952         spin_lock_irqsave(&conf->resync_lock, flags);
953         conf->barrier--;
954         spin_unlock_irqrestore(&conf->resync_lock, flags);
955         wake_up(&conf->wait_barrier);
956 }
957
958 static void wait_barrier(struct r10conf *conf)
959 {
960         spin_lock_irq(&conf->resync_lock);
961         if (conf->barrier) {
962                 conf->nr_waiting++;
963                 /* Wait for the barrier to drop.
964                  * However if there are already pending
965                  * requests (preventing the barrier from
966                  * rising completely), and the
967                  * pre-process bio queue isn't empty,
968                  * then don't wait, as we need to empty
969                  * that queue to get the nr_pending
970                  * count down.
971                  */
972                 raid10_log(conf->mddev, "wait barrier");
973                 wait_event_lock_irq(conf->wait_barrier,
974                                     !conf->barrier ||
975                                     (atomic_read(&conf->nr_pending) &&
976                                      current->bio_list &&
977                                      !bio_list_empty(current->bio_list)),
978                                     conf->resync_lock);
979                 conf->nr_waiting--;
980                 if (!conf->nr_waiting)
981                         wake_up(&conf->wait_barrier);
982         }
983         atomic_inc(&conf->nr_pending);
984         spin_unlock_irq(&conf->resync_lock);
985 }
986
987 static void allow_barrier(struct r10conf *conf)
988 {
989         if ((atomic_dec_and_test(&conf->nr_pending)) ||
990                         (conf->array_freeze_pending))
991                 wake_up(&conf->wait_barrier);
992 }
993
994 static void freeze_array(struct r10conf *conf, int extra)
995 {
996         /* stop syncio and normal IO and wait for everything to
997          * go quiet.
998          * We increment barrier and nr_waiting, and then
999          * wait until nr_pending match nr_queued+extra
1000          * This is called in the context of one normal IO request
1001          * that has failed. Thus any sync request that might be pending
1002          * will be blocked by nr_pending, and we need to wait for
1003          * pending IO requests to complete or be queued for re-try.
1004          * Thus the number queued (nr_queued) plus this request (extra)
1005          * must match the number of pending IOs (nr_pending) before
1006          * we continue.
1007          */
1008         spin_lock_irq(&conf->resync_lock);
1009         conf->array_freeze_pending++;
1010         conf->barrier++;
1011         conf->nr_waiting++;
1012         wait_event_lock_irq_cmd(conf->wait_barrier,
1013                                 atomic_read(&conf->nr_pending) == conf->nr_queued+extra,
1014                                 conf->resync_lock,
1015                                 flush_pending_writes(conf));
1016
1017         conf->array_freeze_pending--;
1018         spin_unlock_irq(&conf->resync_lock);
1019 }
1020
1021 static void unfreeze_array(struct r10conf *conf)
1022 {
1023         /* reverse the effect of the freeze */
1024         spin_lock_irq(&conf->resync_lock);
1025         conf->barrier--;
1026         conf->nr_waiting--;
1027         wake_up(&conf->wait_barrier);
1028         spin_unlock_irq(&conf->resync_lock);
1029 }
1030
1031 static sector_t choose_data_offset(struct r10bio *r10_bio,
1032                                    struct md_rdev *rdev)
1033 {
1034         if (!test_bit(MD_RECOVERY_RESHAPE, &rdev->mddev->recovery) ||
1035             test_bit(R10BIO_Previous, &r10_bio->state))
1036                 return rdev->data_offset;
1037         else
1038                 return rdev->new_data_offset;
1039 }
1040
1041 struct raid10_plug_cb {
1042         struct blk_plug_cb      cb;
1043         struct bio_list         pending;
1044         int                     pending_cnt;
1045 };
1046
1047 static void raid10_unplug(struct blk_plug_cb *cb, bool from_schedule)
1048 {
1049         struct raid10_plug_cb *plug = container_of(cb, struct raid10_plug_cb,
1050                                                    cb);
1051         struct mddev *mddev = plug->cb.data;
1052         struct r10conf *conf = mddev->private;
1053         struct bio *bio;
1054
1055         if (from_schedule || current->bio_list) {
1056                 spin_lock_irq(&conf->device_lock);
1057                 bio_list_merge(&conf->pending_bio_list, &plug->pending);
1058                 conf->pending_count += plug->pending_cnt;
1059                 spin_unlock_irq(&conf->device_lock);
1060                 wake_up(&conf->wait_barrier);
1061                 md_wakeup_thread(mddev->thread);
1062                 kfree(plug);
1063                 return;
1064         }
1065
1066         /* we aren't scheduling, so we can do the write-out directly. */
1067         bio = bio_list_get(&plug->pending);
1068         bitmap_unplug(mddev->bitmap);
1069         wake_up(&conf->wait_barrier);
1070
1071         while (bio) { /* submit pending writes */
1072                 struct bio *next = bio->bi_next;
1073                 struct md_rdev *rdev = (void*)bio->bi_bdev;
1074                 bio->bi_next = NULL;
1075                 bio->bi_bdev = rdev->bdev;
1076                 if (test_bit(Faulty, &rdev->flags)) {
1077                         bio->bi_error = -EIO;
1078                         bio_endio(bio);
1079                 } else if (unlikely((bio_op(bio) ==  REQ_OP_DISCARD) &&
1080                                     !blk_queue_discard(bdev_get_queue(bio->bi_bdev))))
1081                         /* Just ignore it */
1082                         bio_endio(bio);
1083                 else
1084                         generic_make_request(bio);
1085                 bio = next;
1086         }
1087         kfree(plug);
1088 }
1089
1090 static void __make_request(struct mddev *mddev, struct bio *bio)
1091 {
1092         struct r10conf *conf = mddev->private;
1093         struct r10bio *r10_bio;
1094         struct bio *read_bio;
1095         int i;
1096         const int op = bio_op(bio);
1097         const int rw = bio_data_dir(bio);
1098         const unsigned long do_sync = (bio->bi_opf & REQ_SYNC);
1099         const unsigned long do_fua = (bio->bi_opf & REQ_FUA);
1100         unsigned long flags;
1101         struct md_rdev *blocked_rdev;
1102         struct blk_plug_cb *cb;
1103         struct raid10_plug_cb *plug = NULL;
1104         int sectors_handled;
1105         int max_sectors;
1106         int sectors;
1107
1108         md_write_start(mddev, bio);
1109
1110         /*
1111          * Register the new request and wait if the reconstruction
1112          * thread has put up a bar for new requests.
1113          * Continue immediately if no resync is active currently.
1114          */
1115         wait_barrier(conf);
1116
1117         sectors = bio_sectors(bio);
1118         while (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
1119             bio->bi_iter.bi_sector < conf->reshape_progress &&
1120             bio->bi_iter.bi_sector + sectors > conf->reshape_progress) {
1121                 /* IO spans the reshape position.  Need to wait for
1122                  * reshape to pass
1123                  */
1124                 raid10_log(conf->mddev, "wait reshape");
1125                 allow_barrier(conf);
1126                 wait_event(conf->wait_barrier,
1127                            conf->reshape_progress <= bio->bi_iter.bi_sector ||
1128                            conf->reshape_progress >= bio->bi_iter.bi_sector +
1129                            sectors);
1130                 wait_barrier(conf);
1131         }
1132         if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
1133             bio_data_dir(bio) == WRITE &&
1134             (mddev->reshape_backwards
1135              ? (bio->bi_iter.bi_sector < conf->reshape_safe &&
1136                 bio->bi_iter.bi_sector + sectors > conf->reshape_progress)
1137              : (bio->bi_iter.bi_sector + sectors > conf->reshape_safe &&
1138                 bio->bi_iter.bi_sector < conf->reshape_progress))) {
1139                 /* Need to update reshape_position in metadata */
1140                 mddev->reshape_position = conf->reshape_progress;
1141                 set_mask_bits(&mddev->sb_flags, 0,
1142                               BIT(MD_SB_CHANGE_DEVS) | BIT(MD_SB_CHANGE_PENDING));
1143                 md_wakeup_thread(mddev->thread);
1144                 raid10_log(conf->mddev, "wait reshape metadata");
1145                 wait_event(mddev->sb_wait,
1146                            !test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags));
1147
1148                 conf->reshape_safe = mddev->reshape_position;
1149         }
1150
1151         r10_bio = mempool_alloc(conf->r10bio_pool, GFP_NOIO);
1152
1153         r10_bio->master_bio = bio;
1154         r10_bio->sectors = sectors;
1155
1156         r10_bio->mddev = mddev;
1157         r10_bio->sector = bio->bi_iter.bi_sector;
1158         r10_bio->state = 0;
1159
1160         /* We might need to issue multiple reads to different
1161          * devices if there are bad blocks around, so we keep
1162          * track of the number of reads in bio->bi_phys_segments.
1163          * If this is 0, there is only one r10_bio and no locking
1164          * will be needed when the request completes.  If it is
1165          * non-zero, then it is the number of not-completed requests.
1166          */
1167         bio->bi_phys_segments = 0;
1168         bio_clear_flag(bio, BIO_SEG_VALID);
1169
1170         if (rw == READ) {
1171                 /*
1172                  * read balancing logic:
1173                  */
1174                 struct md_rdev *rdev;
1175                 int slot;
1176
1177 read_again:
1178                 rdev = read_balance(conf, r10_bio, &max_sectors);
1179                 if (!rdev) {
1180                         raid_end_bio_io(r10_bio);
1181                         return;
1182                 }
1183                 slot = r10_bio->read_slot;
1184
1185                 read_bio = bio_clone_mddev(bio, GFP_NOIO, mddev);
1186                 bio_trim(read_bio, r10_bio->sector - bio->bi_iter.bi_sector,
1187                          max_sectors);
1188
1189                 r10_bio->devs[slot].bio = read_bio;
1190                 r10_bio->devs[slot].rdev = rdev;
1191
1192                 read_bio->bi_iter.bi_sector = r10_bio->devs[slot].addr +
1193                         choose_data_offset(r10_bio, rdev);
1194                 read_bio->bi_bdev = rdev->bdev;
1195                 read_bio->bi_end_io = raid10_end_read_request;
1196                 bio_set_op_attrs(read_bio, op, do_sync);
1197                 if (test_bit(FailFast, &rdev->flags) &&
1198                     test_bit(R10BIO_FailFast, &r10_bio->state))
1199                         read_bio->bi_opf |= MD_FAILFAST;
1200                 read_bio->bi_private = r10_bio;
1201
1202                 if (mddev->gendisk)
1203                         trace_block_bio_remap(bdev_get_queue(read_bio->bi_bdev),
1204                                               read_bio, disk_devt(mddev->gendisk),
1205                                               r10_bio->sector);
1206                 if (max_sectors < r10_bio->sectors) {
1207                         /* Could not read all from this device, so we will
1208                          * need another r10_bio.
1209                          */
1210                         sectors_handled = (r10_bio->sector + max_sectors
1211                                            - bio->bi_iter.bi_sector);
1212                         r10_bio->sectors = max_sectors;
1213                         spin_lock_irq(&conf->device_lock);
1214                         if (bio->bi_phys_segments == 0)
1215                                 bio->bi_phys_segments = 2;
1216                         else
1217                                 bio->bi_phys_segments++;
1218                         spin_unlock_irq(&conf->device_lock);
1219                         /* Cannot call generic_make_request directly
1220                          * as that will be queued in __generic_make_request
1221                          * and subsequent mempool_alloc might block
1222                          * waiting for it.  so hand bio over to raid10d.
1223                          */
1224                         reschedule_retry(r10_bio);
1225
1226                         r10_bio = mempool_alloc(conf->r10bio_pool, GFP_NOIO);
1227
1228                         r10_bio->master_bio = bio;
1229                         r10_bio->sectors = bio_sectors(bio) - sectors_handled;
1230                         r10_bio->state = 0;
1231                         r10_bio->mddev = mddev;
1232                         r10_bio->sector = bio->bi_iter.bi_sector +
1233                                 sectors_handled;
1234                         goto read_again;
1235                 } else
1236                         generic_make_request(read_bio);
1237                 return;
1238         }
1239
1240         /*
1241          * WRITE:
1242          */
1243         if (conf->pending_count >= max_queued_requests) {
1244                 md_wakeup_thread(mddev->thread);
1245                 raid10_log(mddev, "wait queued");
1246                 wait_event(conf->wait_barrier,
1247                            conf->pending_count < max_queued_requests);
1248         }
1249         /* first select target devices under rcu_lock and
1250          * inc refcount on their rdev.  Record them by setting
1251          * bios[x] to bio
1252          * If there are known/acknowledged bad blocks on any device
1253          * on which we have seen a write error, we want to avoid
1254          * writing to those blocks.  This potentially requires several
1255          * writes to write around the bad blocks.  Each set of writes
1256          * gets its own r10_bio with a set of bios attached.  The number
1257          * of r10_bios is recored in bio->bi_phys_segments just as with
1258          * the read case.
1259          */
1260
1261         r10_bio->read_slot = -1; /* make sure repl_bio gets freed */
1262         raid10_find_phys(conf, r10_bio);
1263 retry_write:
1264         blocked_rdev = NULL;
1265         rcu_read_lock();
1266         max_sectors = r10_bio->sectors;
1267
1268         for (i = 0;  i < conf->copies; i++) {
1269                 int d = r10_bio->devs[i].devnum;
1270                 struct md_rdev *rdev = rcu_dereference(conf->mirrors[d].rdev);
1271                 struct md_rdev *rrdev = rcu_dereference(
1272                         conf->mirrors[d].replacement);
1273                 if (rdev == rrdev)
1274                         rrdev = NULL;
1275                 if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) {
1276                         atomic_inc(&rdev->nr_pending);
1277                         blocked_rdev = rdev;
1278                         break;
1279                 }
1280                 if (rrdev && unlikely(test_bit(Blocked, &rrdev->flags))) {
1281                         atomic_inc(&rrdev->nr_pending);
1282                         blocked_rdev = rrdev;
1283                         break;
1284                 }
1285                 if (rdev && (test_bit(Faulty, &rdev->flags)))
1286                         rdev = NULL;
1287                 if (rrdev && (test_bit(Faulty, &rrdev->flags)))
1288                         rrdev = NULL;
1289
1290                 r10_bio->devs[i].bio = NULL;
1291                 r10_bio->devs[i].repl_bio = NULL;
1292
1293                 if (!rdev && !rrdev) {
1294                         set_bit(R10BIO_Degraded, &r10_bio->state);
1295                         continue;
1296                 }
1297                 if (rdev && test_bit(WriteErrorSeen, &rdev->flags)) {
1298                         sector_t first_bad;
1299                         sector_t dev_sector = r10_bio->devs[i].addr;
1300                         int bad_sectors;
1301                         int is_bad;
1302
1303                         is_bad = is_badblock(rdev, dev_sector,
1304                                              max_sectors,
1305                                              &first_bad, &bad_sectors);
1306                         if (is_bad < 0) {
1307                                 /* Mustn't write here until the bad block
1308                                  * is acknowledged
1309                                  */
1310                                 atomic_inc(&rdev->nr_pending);
1311                                 set_bit(BlockedBadBlocks, &rdev->flags);
1312                                 blocked_rdev = rdev;
1313                                 break;
1314                         }
1315                         if (is_bad && first_bad <= dev_sector) {
1316                                 /* Cannot write here at all */
1317                                 bad_sectors -= (dev_sector - first_bad);
1318                                 if (bad_sectors < max_sectors)
1319                                         /* Mustn't write more than bad_sectors
1320                                          * to other devices yet
1321                                          */
1322                                         max_sectors = bad_sectors;
1323                                 /* We don't set R10BIO_Degraded as that
1324                                  * only applies if the disk is missing,
1325                                  * so it might be re-added, and we want to
1326                                  * know to recover this chunk.
1327                                  * In this case the device is here, and the
1328                                  * fact that this chunk is not in-sync is
1329                                  * recorded in the bad block log.
1330                                  */
1331                                 continue;
1332                         }
1333                         if (is_bad) {
1334                                 int good_sectors = first_bad - dev_sector;
1335                                 if (good_sectors < max_sectors)
1336                                         max_sectors = good_sectors;
1337                         }
1338                 }
1339                 if (rdev) {
1340                         r10_bio->devs[i].bio = bio;
1341                         atomic_inc(&rdev->nr_pending);
1342                 }
1343                 if (rrdev) {
1344                         r10_bio->devs[i].repl_bio = bio;
1345                         atomic_inc(&rrdev->nr_pending);
1346                 }
1347         }
1348         rcu_read_unlock();
1349
1350         if (unlikely(blocked_rdev)) {
1351                 /* Have to wait for this device to get unblocked, then retry */
1352                 int j;
1353                 int d;
1354
1355                 for (j = 0; j < i; j++) {
1356                         if (r10_bio->devs[j].bio) {
1357                                 d = r10_bio->devs[j].devnum;
1358                                 rdev_dec_pending(conf->mirrors[d].rdev, mddev);
1359                         }
1360                         if (r10_bio->devs[j].repl_bio) {
1361                                 struct md_rdev *rdev;
1362                                 d = r10_bio->devs[j].devnum;
1363                                 rdev = conf->mirrors[d].replacement;
1364                                 if (!rdev) {
1365                                         /* Race with remove_disk */
1366                                         smp_mb();
1367                                         rdev = conf->mirrors[d].rdev;
1368                                 }
1369                                 rdev_dec_pending(rdev, mddev);
1370                         }
1371                 }
1372                 allow_barrier(conf);
1373                 raid10_log(conf->mddev, "wait rdev %d blocked", blocked_rdev->raid_disk);
1374                 md_wait_for_blocked_rdev(blocked_rdev, mddev);
1375                 wait_barrier(conf);
1376                 goto retry_write;
1377         }
1378
1379         if (max_sectors < r10_bio->sectors) {
1380                 /* We are splitting this into multiple parts, so
1381                  * we need to prepare for allocating another r10_bio.
1382                  */
1383                 r10_bio->sectors = max_sectors;
1384                 spin_lock_irq(&conf->device_lock);
1385                 if (bio->bi_phys_segments == 0)
1386                         bio->bi_phys_segments = 2;
1387                 else
1388                         bio->bi_phys_segments++;
1389                 spin_unlock_irq(&conf->device_lock);
1390         }
1391         sectors_handled = r10_bio->sector + max_sectors -
1392                 bio->bi_iter.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                         struct md_rdev *rdev = conf->mirrors[d].rdev;
1402                         mbio = bio_clone_mddev(bio, GFP_NOIO, mddev);
1403                         bio_trim(mbio, r10_bio->sector - bio->bi_iter.bi_sector,
1404                                  max_sectors);
1405                         r10_bio->devs[i].bio = mbio;
1406
1407                         mbio->bi_iter.bi_sector = (r10_bio->devs[i].addr+
1408                                            choose_data_offset(r10_bio,
1409                                                               rdev));
1410                         mbio->bi_bdev = rdev->bdev;
1411                         mbio->bi_end_io = raid10_end_write_request;
1412                         bio_set_op_attrs(mbio, op, do_sync | do_fua);
1413                         if (test_bit(FailFast, &conf->mirrors[d].rdev->flags) &&
1414                             enough(conf, d))
1415                                 mbio->bi_opf |= MD_FAILFAST;
1416                         mbio->bi_private = r10_bio;
1417
1418                         if (conf->mddev->gendisk)
1419                                 trace_block_bio_remap(bdev_get_queue(mbio->bi_bdev),
1420                                                       mbio, disk_devt(conf->mddev->gendisk),
1421                                                       r10_bio->sector);
1422                         /* flush_pending_writes() needs access to the rdev so...*/
1423                         mbio->bi_bdev = (void*)rdev;
1424
1425                         atomic_inc(&r10_bio->remaining);
1426
1427                         cb = blk_check_plugged(raid10_unplug, mddev,
1428                                                sizeof(*plug));
1429                         if (cb)
1430                                 plug = container_of(cb, struct raid10_plug_cb,
1431                                                     cb);
1432                         else
1433                                 plug = NULL;
1434                         spin_lock_irqsave(&conf->device_lock, flags);
1435                         if (plug) {
1436                                 bio_list_add(&plug->pending, mbio);
1437                                 plug->pending_cnt++;
1438                         } else {
1439                                 bio_list_add(&conf->pending_bio_list, mbio);
1440                                 conf->pending_count++;
1441                         }
1442                         spin_unlock_irqrestore(&conf->device_lock, flags);
1443                         if (!plug)
1444                                 md_wakeup_thread(mddev->thread);
1445                 }
1446
1447                 if (r10_bio->devs[i].repl_bio) {
1448                         struct md_rdev *rdev = conf->mirrors[d].replacement;
1449                         if (rdev == NULL) {
1450                                 /* Replacement just got moved to main 'rdev' */
1451                                 smp_mb();
1452                                 rdev = conf->mirrors[d].rdev;
1453                         }
1454                         mbio = bio_clone_mddev(bio, GFP_NOIO, mddev);
1455                         bio_trim(mbio, r10_bio->sector - bio->bi_iter.bi_sector,
1456                                  max_sectors);
1457                         r10_bio->devs[i].repl_bio = mbio;
1458
1459                         mbio->bi_iter.bi_sector = (r10_bio->devs[i].addr +
1460                                            choose_data_offset(
1461                                                    r10_bio, rdev));
1462                         mbio->bi_bdev = rdev->bdev;
1463                         mbio->bi_end_io = raid10_end_write_request;
1464                         bio_set_op_attrs(mbio, op, do_sync | do_fua);
1465                         mbio->bi_private = r10_bio;
1466
1467                         if (conf->mddev->gendisk)
1468                                 trace_block_bio_remap(bdev_get_queue(mbio->bi_bdev),
1469                                                       mbio, disk_devt(conf->mddev->gendisk),
1470                                                       r10_bio->sector);
1471                         /* flush_pending_writes() needs access to the rdev so...*/
1472                         mbio->bi_bdev = (void*)rdev;
1473
1474                         atomic_inc(&r10_bio->remaining);
1475                         spin_lock_irqsave(&conf->device_lock, flags);
1476                         bio_list_add(&conf->pending_bio_list, mbio);
1477                         conf->pending_count++;
1478                         spin_unlock_irqrestore(&conf->device_lock, flags);
1479                         if (!mddev_check_plugged(mddev))
1480                                 md_wakeup_thread(mddev->thread);
1481                 }
1482         }
1483
1484         /* Don't remove the bias on 'remaining' (one_write_done) until
1485          * after checking if we need to go around again.
1486          */
1487
1488         if (sectors_handled < bio_sectors(bio)) {
1489                 one_write_done(r10_bio);
1490                 /* We need another r10_bio.  It has already been counted
1491                  * in bio->bi_phys_segments.
1492                  */
1493                 r10_bio = mempool_alloc(conf->r10bio_pool, GFP_NOIO);
1494
1495                 r10_bio->master_bio = bio;
1496                 r10_bio->sectors = bio_sectors(bio) - sectors_handled;
1497
1498                 r10_bio->mddev = mddev;
1499                 r10_bio->sector = bio->bi_iter.bi_sector + sectors_handled;
1500                 r10_bio->state = 0;
1501                 goto retry_write;
1502         }
1503         one_write_done(r10_bio);
1504 }
1505
1506 static void raid10_make_request(struct mddev *mddev, struct bio *bio)
1507 {
1508         struct r10conf *conf = mddev->private;
1509         sector_t chunk_mask = (conf->geo.chunk_mask & conf->prev.chunk_mask);
1510         int chunk_sects = chunk_mask + 1;
1511
1512         struct bio *split;
1513
1514         if (unlikely(bio->bi_opf & REQ_PREFLUSH)) {
1515                 md_flush_request(mddev, bio);
1516                 return;
1517         }
1518
1519         do {
1520
1521                 /*
1522                  * If this request crosses a chunk boundary, we need to split
1523                  * it.
1524                  */
1525                 if (unlikely((bio->bi_iter.bi_sector & chunk_mask) +
1526                              bio_sectors(bio) > chunk_sects
1527                              && (conf->geo.near_copies < conf->geo.raid_disks
1528                                  || conf->prev.near_copies <
1529                                  conf->prev.raid_disks))) {
1530                         split = bio_split(bio, chunk_sects -
1531                                           (bio->bi_iter.bi_sector &
1532                                            (chunk_sects - 1)),
1533                                           GFP_NOIO, fs_bio_set);
1534                         bio_chain(split, bio);
1535                 } else {
1536                         split = bio;
1537                 }
1538
1539                 __make_request(mddev, split);
1540         } while (split != bio);
1541
1542         /* In case raid10d snuck in to freeze_array */
1543         wake_up(&conf->wait_barrier);
1544 }
1545
1546 static void raid10_status(struct seq_file *seq, struct mddev *mddev)
1547 {
1548         struct r10conf *conf = mddev->private;
1549         int i;
1550
1551         if (conf->geo.near_copies < conf->geo.raid_disks)
1552                 seq_printf(seq, " %dK chunks", mddev->chunk_sectors / 2);
1553         if (conf->geo.near_copies > 1)
1554                 seq_printf(seq, " %d near-copies", conf->geo.near_copies);
1555         if (conf->geo.far_copies > 1) {
1556                 if (conf->geo.far_offset)
1557                         seq_printf(seq, " %d offset-copies", conf->geo.far_copies);
1558                 else
1559                         seq_printf(seq, " %d far-copies", conf->geo.far_copies);
1560                 if (conf->geo.far_set_size != conf->geo.raid_disks)
1561                         seq_printf(seq, " %d devices per set", conf->geo.far_set_size);
1562         }
1563         seq_printf(seq, " [%d/%d] [", conf->geo.raid_disks,
1564                                         conf->geo.raid_disks - mddev->degraded);
1565         rcu_read_lock();
1566         for (i = 0; i < conf->geo.raid_disks; i++) {
1567                 struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
1568                 seq_printf(seq, "%s", rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_");
1569         }
1570         rcu_read_unlock();
1571         seq_printf(seq, "]");
1572 }
1573
1574 /* check if there are enough drives for
1575  * every block to appear on atleast one.
1576  * Don't consider the device numbered 'ignore'
1577  * as we might be about to remove it.
1578  */
1579 static int _enough(struct r10conf *conf, int previous, int ignore)
1580 {
1581         int first = 0;
1582         int has_enough = 0;
1583         int disks, ncopies;
1584         if (previous) {
1585                 disks = conf->prev.raid_disks;
1586                 ncopies = conf->prev.near_copies;
1587         } else {
1588                 disks = conf->geo.raid_disks;
1589                 ncopies = conf->geo.near_copies;
1590         }
1591
1592         rcu_read_lock();
1593         do {
1594                 int n = conf->copies;
1595                 int cnt = 0;
1596                 int this = first;
1597                 while (n--) {
1598                         struct md_rdev *rdev;
1599                         if (this != ignore &&
1600                             (rdev = rcu_dereference(conf->mirrors[this].rdev)) &&
1601                             test_bit(In_sync, &rdev->flags))
1602                                 cnt++;
1603                         this = (this+1) % disks;
1604                 }
1605                 if (cnt == 0)
1606                         goto out;
1607                 first = (first + ncopies) % disks;
1608         } while (first != 0);
1609         has_enough = 1;
1610 out:
1611         rcu_read_unlock();
1612         return has_enough;
1613 }
1614
1615 static int enough(struct r10conf *conf, int ignore)
1616 {
1617         /* when calling 'enough', both 'prev' and 'geo' must
1618          * be stable.
1619          * This is ensured if ->reconfig_mutex or ->device_lock
1620          * is held.
1621          */
1622         return _enough(conf, 0, ignore) &&
1623                 _enough(conf, 1, ignore);
1624 }
1625
1626 static void raid10_error(struct mddev *mddev, struct md_rdev *rdev)
1627 {
1628         char b[BDEVNAME_SIZE];
1629         struct r10conf *conf = mddev->private;
1630         unsigned long flags;
1631
1632         /*
1633          * If it is not operational, then we have already marked it as dead
1634          * else if it is the last working disks, ignore the error, let the
1635          * next level up know.
1636          * else mark the drive as failed
1637          */
1638         spin_lock_irqsave(&conf->device_lock, flags);
1639         if (test_bit(In_sync, &rdev->flags)
1640             && !enough(conf, rdev->raid_disk)) {
1641                 /*
1642                  * Don't fail the drive, just return an IO error.
1643                  */
1644                 spin_unlock_irqrestore(&conf->device_lock, flags);
1645                 return;
1646         }
1647         if (test_and_clear_bit(In_sync, &rdev->flags))
1648                 mddev->degraded++;
1649         /*
1650          * If recovery is running, make sure it aborts.
1651          */
1652         set_bit(MD_RECOVERY_INTR, &mddev->recovery);
1653         set_bit(Blocked, &rdev->flags);
1654         set_bit(Faulty, &rdev->flags);
1655         set_mask_bits(&mddev->sb_flags, 0,
1656                       BIT(MD_SB_CHANGE_DEVS) | BIT(MD_SB_CHANGE_PENDING));
1657         spin_unlock_irqrestore(&conf->device_lock, flags);
1658         pr_crit("md/raid10:%s: Disk failure on %s, disabling device.\n"
1659                 "md/raid10:%s: Operation continuing on %d devices.\n",
1660                 mdname(mddev), bdevname(rdev->bdev, b),
1661                 mdname(mddev), conf->geo.raid_disks - mddev->degraded);
1662 }
1663
1664 static void print_conf(struct r10conf *conf)
1665 {
1666         int i;
1667         struct md_rdev *rdev;
1668
1669         pr_debug("RAID10 conf printout:\n");
1670         if (!conf) {
1671                 pr_debug("(!conf)\n");
1672                 return;
1673         }
1674         pr_debug(" --- wd:%d rd:%d\n", conf->geo.raid_disks - conf->mddev->degraded,
1675                  conf->geo.raid_disks);
1676
1677         /* This is only called with ->reconfix_mutex held, so
1678          * rcu protection of rdev is not needed */
1679         for (i = 0; i < conf->geo.raid_disks; i++) {
1680                 char b[BDEVNAME_SIZE];
1681                 rdev = conf->mirrors[i].rdev;
1682                 if (rdev)
1683                         pr_debug(" disk %d, wo:%d, o:%d, dev:%s\n",
1684                                  i, !test_bit(In_sync, &rdev->flags),
1685                                  !test_bit(Faulty, &rdev->flags),
1686                                  bdevname(rdev->bdev,b));
1687         }
1688 }
1689
1690 static void close_sync(struct r10conf *conf)
1691 {
1692         wait_barrier(conf);
1693         allow_barrier(conf);
1694
1695         mempool_destroy(conf->r10buf_pool);
1696         conf->r10buf_pool = NULL;
1697 }
1698
1699 static int raid10_spare_active(struct mddev *mddev)
1700 {
1701         int i;
1702         struct r10conf *conf = mddev->private;
1703         struct raid10_info *tmp;
1704         int count = 0;
1705         unsigned long flags;
1706
1707         /*
1708          * Find all non-in_sync disks within the RAID10 configuration
1709          * and mark them in_sync
1710          */
1711         for (i = 0; i < conf->geo.raid_disks; i++) {
1712                 tmp = conf->mirrors + i;
1713                 if (tmp->replacement
1714                     && tmp->replacement->recovery_offset == MaxSector
1715                     && !test_bit(Faulty, &tmp->replacement->flags)
1716                     && !test_and_set_bit(In_sync, &tmp->replacement->flags)) {
1717                         /* Replacement has just become active */
1718                         if (!tmp->rdev
1719                             || !test_and_clear_bit(In_sync, &tmp->rdev->flags))
1720                                 count++;
1721                         if (tmp->rdev) {
1722                                 /* Replaced device not technically faulty,
1723                                  * but we need to be sure it gets removed
1724                                  * and never re-added.
1725                                  */
1726                                 set_bit(Faulty, &tmp->rdev->flags);
1727                                 sysfs_notify_dirent_safe(
1728                                         tmp->rdev->sysfs_state);
1729                         }
1730                         sysfs_notify_dirent_safe(tmp->replacement->sysfs_state);
1731                 } else if (tmp->rdev
1732                            && tmp->rdev->recovery_offset == MaxSector
1733                            && !test_bit(Faulty, &tmp->rdev->flags)
1734                            && !test_and_set_bit(In_sync, &tmp->rdev->flags)) {
1735                         count++;
1736                         sysfs_notify_dirent_safe(tmp->rdev->sysfs_state);
1737                 }
1738         }
1739         spin_lock_irqsave(&conf->device_lock, flags);
1740         mddev->degraded -= count;
1741         spin_unlock_irqrestore(&conf->device_lock, flags);
1742
1743         print_conf(conf);
1744         return count;
1745 }
1746
1747 static int raid10_add_disk(struct mddev *mddev, struct md_rdev *rdev)
1748 {
1749         struct r10conf *conf = mddev->private;
1750         int err = -EEXIST;
1751         int mirror;
1752         int first = 0;
1753         int last = conf->geo.raid_disks - 1;
1754
1755         if (mddev->recovery_cp < MaxSector)
1756                 /* only hot-add to in-sync arrays, as recovery is
1757                  * very different from resync
1758                  */
1759                 return -EBUSY;
1760         if (rdev->saved_raid_disk < 0 && !_enough(conf, 1, -1))
1761                 return -EINVAL;
1762
1763         if (md_integrity_add_rdev(rdev, mddev))
1764                 return -ENXIO;
1765
1766         if (rdev->raid_disk >= 0)
1767                 first = last = rdev->raid_disk;
1768
1769         if (rdev->saved_raid_disk >= first &&
1770             conf->mirrors[rdev->saved_raid_disk].rdev == NULL)
1771                 mirror = rdev->saved_raid_disk;
1772         else
1773                 mirror = first;
1774         for ( ; mirror <= last ; mirror++) {
1775                 struct raid10_info *p = &conf->mirrors[mirror];
1776                 if (p->recovery_disabled == mddev->recovery_disabled)
1777                         continue;
1778                 if (p->rdev) {
1779                         if (!test_bit(WantReplacement, &p->rdev->flags) ||
1780                             p->replacement != NULL)
1781                                 continue;
1782                         clear_bit(In_sync, &rdev->flags);
1783                         set_bit(Replacement, &rdev->flags);
1784                         rdev->raid_disk = mirror;
1785                         err = 0;
1786                         if (mddev->gendisk)
1787                                 disk_stack_limits(mddev->gendisk, rdev->bdev,
1788                                                   rdev->data_offset << 9);
1789                         conf->fullsync = 1;
1790                         rcu_assign_pointer(p->replacement, rdev);
1791                         break;
1792                 }
1793
1794                 if (mddev->gendisk)
1795                         disk_stack_limits(mddev->gendisk, rdev->bdev,
1796                                           rdev->data_offset << 9);
1797
1798                 p->head_position = 0;
1799                 p->recovery_disabled = mddev->recovery_disabled - 1;
1800                 rdev->raid_disk = mirror;
1801                 err = 0;
1802                 if (rdev->saved_raid_disk != mirror)
1803                         conf->fullsync = 1;
1804                 rcu_assign_pointer(p->rdev, rdev);
1805                 break;
1806         }
1807         if (mddev->queue && blk_queue_discard(bdev_get_queue(rdev->bdev)))
1808                 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, mddev->queue);
1809
1810         print_conf(conf);
1811         return err;
1812 }
1813
1814 static int raid10_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
1815 {
1816         struct r10conf *conf = mddev->private;
1817         int err = 0;
1818         int number = rdev->raid_disk;
1819         struct md_rdev **rdevp;
1820         struct raid10_info *p = conf->mirrors + number;
1821
1822         print_conf(conf);
1823         if (rdev == p->rdev)
1824                 rdevp = &p->rdev;
1825         else if (rdev == p->replacement)
1826                 rdevp = &p->replacement;
1827         else
1828                 return 0;
1829
1830         if (test_bit(In_sync, &rdev->flags) ||
1831             atomic_read(&rdev->nr_pending)) {
1832                 err = -EBUSY;
1833                 goto abort;
1834         }
1835         /* Only remove non-faulty devices if recovery
1836          * is not possible.
1837          */
1838         if (!test_bit(Faulty, &rdev->flags) &&
1839             mddev->recovery_disabled != p->recovery_disabled &&
1840             (!p->replacement || p->replacement == rdev) &&
1841             number < conf->geo.raid_disks &&
1842             enough(conf, -1)) {
1843                 err = -EBUSY;
1844                 goto abort;
1845         }
1846         *rdevp = NULL;
1847         if (!test_bit(RemoveSynchronized, &rdev->flags)) {
1848                 synchronize_rcu();
1849                 if (atomic_read(&rdev->nr_pending)) {
1850                         /* lost the race, try later */
1851                         err = -EBUSY;
1852                         *rdevp = rdev;
1853                         goto abort;
1854                 }
1855         }
1856         if (p->replacement) {
1857                 /* We must have just cleared 'rdev' */
1858                 p->rdev = p->replacement;
1859                 clear_bit(Replacement, &p->replacement->flags);
1860                 smp_mb(); /* Make sure other CPUs may see both as identical
1861                            * but will never see neither -- if they are careful.
1862                            */
1863                 p->replacement = NULL;
1864                 clear_bit(WantReplacement, &rdev->flags);
1865         } else
1866                 /* We might have just remove the Replacement as faulty
1867                  * Clear the flag just in case
1868                  */
1869                 clear_bit(WantReplacement, &rdev->flags);
1870
1871         err = md_integrity_register(mddev);
1872
1873 abort:
1874
1875         print_conf(conf);
1876         return err;
1877 }
1878
1879 static void end_sync_read(struct bio *bio)
1880 {
1881         struct r10bio *r10_bio = bio->bi_private;
1882         struct r10conf *conf = r10_bio->mddev->private;
1883         int d;
1884
1885         if (bio == r10_bio->master_bio) {
1886                 /* this is a reshape read */
1887                 d = r10_bio->read_slot; /* really the read dev */
1888         } else
1889                 d = find_bio_disk(conf, r10_bio, bio, NULL, NULL);
1890
1891         if (!bio->bi_error)
1892                 set_bit(R10BIO_Uptodate, &r10_bio->state);
1893         else
1894                 /* The write handler will notice the lack of
1895                  * R10BIO_Uptodate and record any errors etc
1896                  */
1897                 atomic_add(r10_bio->sectors,
1898                            &conf->mirrors[d].rdev->corrected_errors);
1899
1900         /* for reconstruct, we always reschedule after a read.
1901          * for resync, only after all reads
1902          */
1903         rdev_dec_pending(conf->mirrors[d].rdev, conf->mddev);
1904         if (test_bit(R10BIO_IsRecover, &r10_bio->state) ||
1905             atomic_dec_and_test(&r10_bio->remaining)) {
1906                 /* we have read all the blocks,
1907                  * do the comparison in process context in raid10d
1908                  */
1909                 reschedule_retry(r10_bio);
1910         }
1911 }
1912
1913 static void end_sync_request(struct r10bio *r10_bio)
1914 {
1915         struct mddev *mddev = r10_bio->mddev;
1916
1917         while (atomic_dec_and_test(&r10_bio->remaining)) {
1918                 if (r10_bio->master_bio == NULL) {
1919                         /* the primary of several recovery bios */
1920                         sector_t s = r10_bio->sectors;
1921                         if (test_bit(R10BIO_MadeGood, &r10_bio->state) ||
1922                             test_bit(R10BIO_WriteError, &r10_bio->state))
1923                                 reschedule_retry(r10_bio);
1924                         else
1925                                 put_buf(r10_bio);
1926                         md_done_sync(mddev, s, 1);
1927                         break;
1928                 } else {
1929                         struct r10bio *r10_bio2 = (struct r10bio *)r10_bio->master_bio;
1930                         if (test_bit(R10BIO_MadeGood, &r10_bio->state) ||
1931                             test_bit(R10BIO_WriteError, &r10_bio->state))
1932                                 reschedule_retry(r10_bio);
1933                         else
1934                                 put_buf(r10_bio);
1935                         r10_bio = r10_bio2;
1936                 }
1937         }
1938 }
1939
1940 static void end_sync_write(struct bio *bio)
1941 {
1942         struct r10bio *r10_bio = bio->bi_private;
1943         struct mddev *mddev = r10_bio->mddev;
1944         struct r10conf *conf = mddev->private;
1945         int d;
1946         sector_t first_bad;
1947         int bad_sectors;
1948         int slot;
1949         int repl;
1950         struct md_rdev *rdev = NULL;
1951
1952         d = find_bio_disk(conf, r10_bio, bio, &slot, &repl);
1953         if (repl)
1954                 rdev = conf->mirrors[d].replacement;
1955         else
1956                 rdev = conf->mirrors[d].rdev;
1957
1958         if (bio->bi_error) {
1959                 if (repl)
1960                         md_error(mddev, rdev);
1961                 else {
1962                         set_bit(WriteErrorSeen, &rdev->flags);
1963                         if (!test_and_set_bit(WantReplacement, &rdev->flags))
1964                                 set_bit(MD_RECOVERY_NEEDED,
1965                                         &rdev->mddev->recovery);
1966                         set_bit(R10BIO_WriteError, &r10_bio->state);
1967                 }
1968         } else if (is_badblock(rdev,
1969                              r10_bio->devs[slot].addr,
1970                              r10_bio->sectors,
1971                              &first_bad, &bad_sectors))
1972                 set_bit(R10BIO_MadeGood, &r10_bio->state);
1973
1974         rdev_dec_pending(rdev, mddev);
1975
1976         end_sync_request(r10_bio);
1977 }
1978
1979 /*
1980  * Note: sync and recover and handled very differently for raid10
1981  * This code is for resync.
1982  * For resync, we read through virtual addresses and read all blocks.
1983  * If there is any error, we schedule a write.  The lowest numbered
1984  * drive is authoritative.
1985  * However requests come for physical address, so we need to map.
1986  * For every physical address there are raid_disks/copies virtual addresses,
1987  * which is always are least one, but is not necessarly an integer.
1988  * This means that a physical address can span multiple chunks, so we may
1989  * have to submit multiple io requests for a single sync request.
1990  */
1991 /*
1992  * We check if all blocks are in-sync and only write to blocks that
1993  * aren't in sync
1994  */
1995 static void sync_request_write(struct mddev *mddev, struct r10bio *r10_bio)
1996 {
1997         struct r10conf *conf = mddev->private;
1998         int i, first;
1999         struct bio *tbio, *fbio;
2000         int vcnt;
2001
2002         atomic_set(&r10_bio->remaining, 1);
2003
2004         /* find the first device with a block */
2005         for (i=0; i<conf->copies; i++)
2006                 if (!r10_bio->devs[i].bio->bi_error)
2007                         break;
2008
2009         if (i == conf->copies)
2010                 goto done;
2011
2012         first = i;
2013         fbio = r10_bio->devs[i].bio;
2014         fbio->bi_iter.bi_size = r10_bio->sectors << 9;
2015         fbio->bi_iter.bi_idx = 0;
2016
2017         vcnt = (r10_bio->sectors + (PAGE_SIZE >> 9) - 1) >> (PAGE_SHIFT - 9);
2018         /* now find blocks with errors */
2019         for (i=0 ; i < conf->copies ; i++) {
2020                 int  j, d;
2021                 struct md_rdev *rdev;
2022
2023                 tbio = r10_bio->devs[i].bio;
2024
2025                 if (tbio->bi_end_io != end_sync_read)
2026                         continue;
2027                 if (i == first)
2028                         continue;
2029                 d = r10_bio->devs[i].devnum;
2030                 rdev = conf->mirrors[d].rdev;
2031                 if (!r10_bio->devs[i].bio->bi_error) {
2032                         /* We know that the bi_io_vec layout is the same for
2033                          * both 'first' and 'i', so we just compare them.
2034                          * All vec entries are PAGE_SIZE;
2035                          */
2036                         int sectors = r10_bio->sectors;
2037                         for (j = 0; j < vcnt; j++) {
2038                                 int len = PAGE_SIZE;
2039                                 if (sectors < (len / 512))
2040                                         len = sectors * 512;
2041                                 if (memcmp(page_address(fbio->bi_io_vec[j].bv_page),
2042                                            page_address(tbio->bi_io_vec[j].bv_page),
2043                                            len))
2044                                         break;
2045                                 sectors -= len/512;
2046                         }
2047                         if (j == vcnt)
2048                                 continue;
2049                         atomic64_add(r10_bio->sectors, &mddev->resync_mismatches);
2050                         if (test_bit(MD_RECOVERY_CHECK, &mddev->recovery))
2051                                 /* Don't fix anything. */
2052                                 continue;
2053                 } else if (test_bit(FailFast, &rdev->flags)) {
2054                         /* Just give up on this device */
2055                         md_error(rdev->mddev, rdev);
2056                         continue;
2057                 }
2058                 /* Ok, we need to write this bio, either to correct an
2059                  * inconsistency or to correct an unreadable block.
2060                  * First we need to fixup bv_offset, bv_len and
2061                  * bi_vecs, as the read request might have corrupted these
2062                  */
2063                 bio_reset(tbio);
2064
2065                 tbio->bi_vcnt = vcnt;
2066                 tbio->bi_iter.bi_size = fbio->bi_iter.bi_size;
2067                 tbio->bi_private = r10_bio;
2068                 tbio->bi_iter.bi_sector = r10_bio->devs[i].addr;
2069                 tbio->bi_end_io = end_sync_write;
2070                 bio_set_op_attrs(tbio, REQ_OP_WRITE, 0);
2071
2072                 bio_copy_data(tbio, fbio);
2073
2074                 atomic_inc(&conf->mirrors[d].rdev->nr_pending);
2075                 atomic_inc(&r10_bio->remaining);
2076                 md_sync_acct(conf->mirrors[d].rdev->bdev, bio_sectors(tbio));
2077
2078                 if (test_bit(FailFast, &conf->mirrors[d].rdev->flags))
2079                         tbio->bi_opf |= MD_FAILFAST;
2080                 tbio->bi_iter.bi_sector += conf->mirrors[d].rdev->data_offset;
2081                 tbio->bi_bdev = conf->mirrors[d].rdev->bdev;
2082                 generic_make_request(tbio);
2083         }
2084
2085         /* Now write out to any replacement devices
2086          * that are active
2087          */
2088         for (i = 0; i < conf->copies; i++) {
2089                 int d;
2090
2091                 tbio = r10_bio->devs[i].repl_bio;
2092                 if (!tbio || !tbio->bi_end_io)
2093                         continue;
2094                 if (r10_bio->devs[i].bio->bi_end_io != end_sync_write
2095                     && r10_bio->devs[i].bio != fbio)
2096                         bio_copy_data(tbio, fbio);
2097                 d = r10_bio->devs[i].devnum;
2098                 atomic_inc(&r10_bio->remaining);
2099                 md_sync_acct(conf->mirrors[d].replacement->bdev,
2100                              bio_sectors(tbio));
2101                 generic_make_request(tbio);
2102         }
2103
2104 done:
2105         if (atomic_dec_and_test(&r10_bio->remaining)) {
2106                 md_done_sync(mddev, r10_bio->sectors, 1);
2107                 put_buf(r10_bio);
2108         }
2109 }
2110
2111 /*
2112  * Now for the recovery code.
2113  * Recovery happens across physical sectors.
2114  * We recover all non-is_sync drives by finding the virtual address of
2115  * each, and then choose a working drive that also has that virt address.
2116  * There is a separate r10_bio for each non-in_sync drive.
2117  * Only the first two slots are in use. The first for reading,
2118  * The second for writing.
2119  *
2120  */
2121 static void fix_recovery_read_error(struct r10bio *r10_bio)
2122 {
2123         /* We got a read error during recovery.
2124          * We repeat the read in smaller page-sized sections.
2125          * If a read succeeds, write it to the new device or record
2126          * a bad block if we cannot.
2127          * If a read fails, record a bad block on both old and
2128          * new devices.
2129          */
2130         struct mddev *mddev = r10_bio->mddev;
2131         struct r10conf *conf = mddev->private;
2132         struct bio *bio = r10_bio->devs[0].bio;
2133         sector_t sect = 0;
2134         int sectors = r10_bio->sectors;
2135         int idx = 0;
2136         int dr = r10_bio->devs[0].devnum;
2137         int dw = r10_bio->devs[1].devnum;
2138
2139         while (sectors) {
2140                 int s = sectors;
2141                 struct md_rdev *rdev;
2142                 sector_t addr;
2143                 int ok;
2144
2145                 if (s > (PAGE_SIZE>>9))
2146                         s = PAGE_SIZE >> 9;
2147
2148                 rdev = conf->mirrors[dr].rdev;
2149                 addr = r10_bio->devs[0].addr + sect,
2150                 ok = sync_page_io(rdev,
2151                                   addr,
2152                                   s << 9,
2153                                   bio->bi_io_vec[idx].bv_page,
2154                                   REQ_OP_READ, 0, false);
2155                 if (ok) {
2156                         rdev = conf->mirrors[dw].rdev;
2157                         addr = r10_bio->devs[1].addr + sect;
2158                         ok = sync_page_io(rdev,
2159                                           addr,
2160                                           s << 9,
2161                                           bio->bi_io_vec[idx].bv_page,
2162                                           REQ_OP_WRITE, 0, false);
2163                         if (!ok) {
2164                                 set_bit(WriteErrorSeen, &rdev->flags);
2165                                 if (!test_and_set_bit(WantReplacement,
2166                                                       &rdev->flags))
2167                                         set_bit(MD_RECOVERY_NEEDED,
2168                                                 &rdev->mddev->recovery);
2169                         }
2170                 }
2171                 if (!ok) {
2172                         /* We don't worry if we cannot set a bad block -
2173                          * it really is bad so there is no loss in not
2174                          * recording it yet
2175                          */
2176                         rdev_set_badblocks(rdev, addr, s, 0);
2177
2178                         if (rdev != conf->mirrors[dw].rdev) {
2179                                 /* need bad block on destination too */
2180                                 struct md_rdev *rdev2 = conf->mirrors[dw].rdev;
2181                                 addr = r10_bio->devs[1].addr + sect;
2182                                 ok = rdev_set_badblocks(rdev2, addr, s, 0);
2183                                 if (!ok) {
2184                                         /* just abort the recovery */
2185                                         pr_notice("md/raid10:%s: recovery aborted due to read error\n",
2186                                                   mdname(mddev));
2187
2188                                         conf->mirrors[dw].recovery_disabled
2189                                                 = mddev->recovery_disabled;
2190                                         set_bit(MD_RECOVERY_INTR,
2191                                                 &mddev->recovery);
2192                                         break;
2193                                 }
2194                         }
2195                 }
2196
2197                 sectors -= s;
2198                 sect += s;
2199                 idx++;
2200         }
2201 }
2202
2203 static void recovery_request_write(struct mddev *mddev, struct r10bio *r10_bio)
2204 {
2205         struct r10conf *conf = mddev->private;
2206         int d;
2207         struct bio *wbio, *wbio2;
2208
2209         if (!test_bit(R10BIO_Uptodate, &r10_bio->state)) {
2210                 fix_recovery_read_error(r10_bio);
2211                 end_sync_request(r10_bio);
2212                 return;
2213         }
2214
2215         /*
2216          * share the pages with the first bio
2217          * and submit the write request
2218          */
2219         d = r10_bio->devs[1].devnum;
2220         wbio = r10_bio->devs[1].bio;
2221         wbio2 = r10_bio->devs[1].repl_bio;
2222         /* Need to test wbio2->bi_end_io before we call
2223          * generic_make_request as if the former is NULL,
2224          * the latter is free to free wbio2.
2225          */
2226         if (wbio2 && !wbio2->bi_end_io)
2227                 wbio2 = NULL;
2228         if (wbio->bi_end_io) {
2229                 atomic_inc(&conf->mirrors[d].rdev->nr_pending);
2230                 md_sync_acct(conf->mirrors[d].rdev->bdev, bio_sectors(wbio));
2231                 generic_make_request(wbio);
2232         }
2233         if (wbio2) {
2234                 atomic_inc(&conf->mirrors[d].replacement->nr_pending);
2235                 md_sync_acct(conf->mirrors[d].replacement->bdev,
2236                              bio_sectors(wbio2));
2237                 generic_make_request(wbio2);
2238         }
2239 }
2240
2241 /*
2242  * Used by fix_read_error() to decay the per rdev read_errors.
2243  * We halve the read error count for every hour that has elapsed
2244  * since the last recorded read error.
2245  *
2246  */
2247 static void check_decay_read_errors(struct mddev *mddev, struct md_rdev *rdev)
2248 {
2249         long cur_time_mon;
2250         unsigned long hours_since_last;
2251         unsigned int read_errors = atomic_read(&rdev->read_errors);
2252
2253         cur_time_mon = ktime_get_seconds();
2254
2255         if (rdev->last_read_error == 0) {
2256                 /* first time we've seen a read error */
2257                 rdev->last_read_error = cur_time_mon;
2258                 return;
2259         }
2260
2261         hours_since_last = (long)(cur_time_mon -
2262                             rdev->last_read_error) / 3600;
2263
2264         rdev->last_read_error = cur_time_mon;
2265
2266         /*
2267          * if hours_since_last is > the number of bits in read_errors
2268          * just set read errors to 0. We do this to avoid
2269          * overflowing the shift of read_errors by hours_since_last.
2270          */
2271         if (hours_since_last >= 8 * sizeof(read_errors))
2272                 atomic_set(&rdev->read_errors, 0);
2273         else
2274                 atomic_set(&rdev->read_errors, read_errors >> hours_since_last);
2275 }
2276
2277 static int r10_sync_page_io(struct md_rdev *rdev, sector_t sector,
2278                             int sectors, struct page *page, int rw)
2279 {
2280         sector_t first_bad;
2281         int bad_sectors;
2282
2283         if (is_badblock(rdev, sector, sectors, &first_bad, &bad_sectors)
2284             && (rw == READ || test_bit(WriteErrorSeen, &rdev->flags)))
2285                 return -1;
2286         if (sync_page_io(rdev, sector, sectors << 9, page, rw, 0, false))
2287                 /* success */
2288                 return 1;
2289         if (rw == WRITE) {
2290                 set_bit(WriteErrorSeen, &rdev->flags);
2291                 if (!test_and_set_bit(WantReplacement, &rdev->flags))
2292                         set_bit(MD_RECOVERY_NEEDED,
2293                                 &rdev->mddev->recovery);
2294         }
2295         /* need to record an error - either for the block or the device */
2296         if (!rdev_set_badblocks(rdev, sector, sectors, 0))
2297                 md_error(rdev->mddev, rdev);
2298         return 0;
2299 }
2300
2301 /*
2302  * This is a kernel thread which:
2303  *
2304  *      1.      Retries failed read operations on working mirrors.
2305  *      2.      Updates the raid superblock when problems encounter.
2306  *      3.      Performs writes following reads for array synchronising.
2307  */
2308
2309 static void fix_read_error(struct r10conf *conf, struct mddev *mddev, struct r10bio *r10_bio)
2310 {
2311         int sect = 0; /* Offset from r10_bio->sector */
2312         int sectors = r10_bio->sectors;
2313         struct md_rdev*rdev;
2314         int max_read_errors = atomic_read(&mddev->max_corr_read_errors);
2315         int d = r10_bio->devs[r10_bio->read_slot].devnum;
2316
2317         /* still own a reference to this rdev, so it cannot
2318          * have been cleared recently.
2319          */
2320         rdev = conf->mirrors[d].rdev;
2321
2322         if (test_bit(Faulty, &rdev->flags))
2323                 /* drive has already been failed, just ignore any
2324                    more fix_read_error() attempts */
2325                 return;
2326
2327         check_decay_read_errors(mddev, rdev);
2328         atomic_inc(&rdev->read_errors);
2329         if (atomic_read(&rdev->read_errors) > max_read_errors) {
2330                 char b[BDEVNAME_SIZE];
2331                 bdevname(rdev->bdev, b);
2332
2333                 pr_notice("md/raid10:%s: %s: Raid device exceeded read_error threshold [cur %d:max %d]\n",
2334                           mdname(mddev), b,
2335                           atomic_read(&rdev->read_errors), max_read_errors);
2336                 pr_notice("md/raid10:%s: %s: Failing raid device\n",
2337                           mdname(mddev), b);
2338                 md_error(mddev, rdev);
2339                 r10_bio->devs[r10_bio->read_slot].bio = IO_BLOCKED;
2340                 return;
2341         }
2342
2343         while(sectors) {
2344                 int s = sectors;
2345                 int sl = r10_bio->read_slot;
2346                 int success = 0;
2347                 int start;
2348
2349                 if (s > (PAGE_SIZE>>9))
2350                         s = PAGE_SIZE >> 9;
2351
2352                 rcu_read_lock();
2353                 do {
2354                         sector_t first_bad;
2355                         int bad_sectors;
2356
2357                         d = r10_bio->devs[sl].devnum;
2358                         rdev = rcu_dereference(conf->mirrors[d].rdev);
2359                         if (rdev &&
2360                             test_bit(In_sync, &rdev->flags) &&
2361                             !test_bit(Faulty, &rdev->flags) &&
2362                             is_badblock(rdev, r10_bio->devs[sl].addr + sect, s,
2363                                         &first_bad, &bad_sectors) == 0) {
2364                                 atomic_inc(&rdev->nr_pending);
2365                                 rcu_read_unlock();
2366                                 success = sync_page_io(rdev,
2367                                                        r10_bio->devs[sl].addr +
2368                                                        sect,
2369                                                        s<<9,
2370                                                        conf->tmppage,
2371                                                        REQ_OP_READ, 0, false);
2372                                 rdev_dec_pending(rdev, mddev);
2373                                 rcu_read_lock();
2374                                 if (success)
2375                                         break;
2376                         }
2377                         sl++;
2378                         if (sl == conf->copies)
2379                                 sl = 0;
2380                 } while (!success && sl != r10_bio->read_slot);
2381                 rcu_read_unlock();
2382
2383                 if (!success) {
2384                         /* Cannot read from anywhere, just mark the block
2385                          * as bad on the first device to discourage future
2386                          * reads.
2387                          */
2388                         int dn = r10_bio->devs[r10_bio->read_slot].devnum;
2389                         rdev = conf->mirrors[dn].rdev;
2390
2391                         if (!rdev_set_badblocks(
2392                                     rdev,
2393                                     r10_bio->devs[r10_bio->read_slot].addr
2394                                     + sect,
2395                                     s, 0)) {
2396                                 md_error(mddev, rdev);
2397                                 r10_bio->devs[r10_bio->read_slot].bio
2398                                         = IO_BLOCKED;
2399                         }
2400                         break;
2401                 }
2402
2403                 start = sl;
2404                 /* write it back and re-read */
2405                 rcu_read_lock();
2406                 while (sl != r10_bio->read_slot) {
2407                         char b[BDEVNAME_SIZE];
2408
2409                         if (sl==0)
2410                                 sl = conf->copies;
2411                         sl--;
2412                         d = r10_bio->devs[sl].devnum;
2413                         rdev = rcu_dereference(conf->mirrors[d].rdev);
2414                         if (!rdev ||
2415                             test_bit(Faulty, &rdev->flags) ||
2416                             !test_bit(In_sync, &rdev->flags))
2417                                 continue;
2418
2419                         atomic_inc(&rdev->nr_pending);
2420                         rcu_read_unlock();
2421                         if (r10_sync_page_io(rdev,
2422                                              r10_bio->devs[sl].addr +
2423                                              sect,
2424                                              s, conf->tmppage, WRITE)
2425                             == 0) {
2426                                 /* Well, this device is dead */
2427                                 pr_notice("md/raid10:%s: read correction write failed (%d sectors at %llu on %s)\n",
2428                                           mdname(mddev), s,
2429                                           (unsigned long long)(
2430                                                   sect +
2431                                                   choose_data_offset(r10_bio,
2432                                                                      rdev)),
2433                                           bdevname(rdev->bdev, b));
2434                                 pr_notice("md/raid10:%s: %s: failing drive\n",
2435                                           mdname(mddev),
2436                                           bdevname(rdev->bdev, b));
2437                         }
2438                         rdev_dec_pending(rdev, mddev);
2439                         rcu_read_lock();
2440                 }
2441                 sl = start;
2442                 while (sl != r10_bio->read_slot) {
2443                         char b[BDEVNAME_SIZE];
2444
2445                         if (sl==0)
2446                                 sl = conf->copies;
2447                         sl--;
2448                         d = r10_bio->devs[sl].devnum;
2449                         rdev = rcu_dereference(conf->mirrors[d].rdev);
2450                         if (!rdev ||
2451                             test_bit(Faulty, &rdev->flags) ||
2452                             !test_bit(In_sync, &rdev->flags))
2453                                 continue;
2454
2455                         atomic_inc(&rdev->nr_pending);
2456                         rcu_read_unlock();
2457                         switch (r10_sync_page_io(rdev,
2458                                              r10_bio->devs[sl].addr +
2459                                              sect,
2460                                              s, conf->tmppage,
2461                                                  READ)) {
2462                         case 0:
2463                                 /* Well, this device is dead */
2464                                 pr_notice("md/raid10:%s: unable to read back corrected sectors (%d sectors at %llu on %s)\n",
2465                                        mdname(mddev), s,
2466                                        (unsigned long long)(
2467                                                sect +
2468                                                choose_data_offset(r10_bio, rdev)),
2469                                        bdevname(rdev->bdev, b));
2470                                 pr_notice("md/raid10:%s: %s: failing drive\n",
2471                                        mdname(mddev),
2472                                        bdevname(rdev->bdev, b));
2473                                 break;
2474                         case 1:
2475                                 pr_info("md/raid10:%s: read error corrected (%d sectors at %llu on %s)\n",
2476                                        mdname(mddev), s,
2477                                        (unsigned long long)(
2478                                                sect +
2479                                                choose_data_offset(r10_bio, rdev)),
2480                                        bdevname(rdev->bdev, b));
2481                                 atomic_add(s, &rdev->corrected_errors);
2482                         }
2483
2484                         rdev_dec_pending(rdev, mddev);
2485                         rcu_read_lock();
2486                 }
2487                 rcu_read_unlock();
2488
2489                 sectors -= s;
2490                 sect += s;
2491         }
2492 }
2493
2494 static int narrow_write_error(struct r10bio *r10_bio, int i)
2495 {
2496         struct bio *bio = r10_bio->master_bio;
2497         struct mddev *mddev = r10_bio->mddev;
2498         struct r10conf *conf = mddev->private;
2499         struct md_rdev *rdev = conf->mirrors[r10_bio->devs[i].devnum].rdev;
2500         /* bio has the data to be written to slot 'i' where
2501          * we just recently had a write error.
2502          * We repeatedly clone the bio and trim down to one block,
2503          * then try the write.  Where the write fails we record
2504          * a bad block.
2505          * It is conceivable that the bio doesn't exactly align with
2506          * blocks.  We must handle this.
2507          *
2508          * We currently own a reference to the rdev.
2509          */
2510
2511         int block_sectors;
2512         sector_t sector;
2513         int sectors;
2514         int sect_to_write = r10_bio->sectors;
2515         int ok = 1;
2516
2517         if (rdev->badblocks.shift < 0)
2518                 return 0;
2519
2520         block_sectors = roundup(1 << rdev->badblocks.shift,
2521                                 bdev_logical_block_size(rdev->bdev) >> 9);
2522         sector = r10_bio->sector;
2523         sectors = ((r10_bio->sector + block_sectors)
2524                    & ~(sector_t)(block_sectors - 1))
2525                 - sector;
2526
2527         while (sect_to_write) {
2528                 struct bio *wbio;
2529                 sector_t wsector;
2530                 if (sectors > sect_to_write)
2531                         sectors = sect_to_write;
2532                 /* Write at 'sector' for 'sectors' */
2533                 wbio = bio_clone_mddev(bio, GFP_NOIO, mddev);
2534                 bio_trim(wbio, sector - bio->bi_iter.bi_sector, sectors);
2535                 wsector = r10_bio->devs[i].addr + (sector - r10_bio->sector);
2536                 wbio->bi_iter.bi_sector = wsector +
2537                                    choose_data_offset(r10_bio, rdev);
2538                 wbio->bi_bdev = rdev->bdev;
2539                 bio_set_op_attrs(wbio, REQ_OP_WRITE, 0);
2540
2541                 if (submit_bio_wait(wbio) < 0)
2542                         /* Failure! */
2543                         ok = rdev_set_badblocks(rdev, wsector,
2544                                                 sectors, 0)
2545                                 && ok;
2546
2547                 bio_put(wbio);
2548                 sect_to_write -= sectors;
2549                 sector += sectors;
2550                 sectors = block_sectors;
2551         }
2552         return ok;
2553 }
2554
2555 static void handle_read_error(struct mddev *mddev, struct r10bio *r10_bio)
2556 {
2557         int slot = r10_bio->read_slot;
2558         struct bio *bio;
2559         struct r10conf *conf = mddev->private;
2560         struct md_rdev *rdev = r10_bio->devs[slot].rdev;
2561         char b[BDEVNAME_SIZE];
2562         unsigned long do_sync;
2563         int max_sectors;
2564         dev_t bio_dev;
2565         sector_t bio_last_sector;
2566
2567         /* we got a read error. Maybe the drive is bad.  Maybe just
2568          * the block and we can fix it.
2569          * We freeze all other IO, and try reading the block from
2570          * other devices.  When we find one, we re-write
2571          * and check it that fixes the read error.
2572          * This is all done synchronously while the array is
2573          * frozen.
2574          */
2575         bio = r10_bio->devs[slot].bio;
2576         bdevname(bio->bi_bdev, b);
2577         bio_dev = bio->bi_bdev->bd_dev;
2578         bio_last_sector = r10_bio->devs[slot].addr + rdev->data_offset + r10_bio->sectors;
2579         bio_put(bio);
2580         r10_bio->devs[slot].bio = NULL;
2581
2582         if (mddev->ro)
2583                 r10_bio->devs[slot].bio = IO_BLOCKED;
2584         else if (!test_bit(FailFast, &rdev->flags)) {
2585                 freeze_array(conf, 1);
2586                 fix_read_error(conf, mddev, r10_bio);
2587                 unfreeze_array(conf);
2588         } else
2589                 md_error(mddev, rdev);
2590
2591         rdev_dec_pending(rdev, mddev);
2592
2593 read_more:
2594         rdev = read_balance(conf, r10_bio, &max_sectors);
2595         if (rdev == NULL) {
2596                 pr_crit_ratelimited("md/raid10:%s: %s: unrecoverable I/O read error for block %llu\n",
2597                                     mdname(mddev), b,
2598                                     (unsigned long long)r10_bio->sector);
2599                 raid_end_bio_io(r10_bio);
2600                 return;
2601         }
2602
2603         do_sync = (r10_bio->master_bio->bi_opf & REQ_SYNC);
2604         slot = r10_bio->read_slot;
2605         pr_err_ratelimited("md/raid10:%s: %s: redirecting sector %llu to another mirror\n",
2606                            mdname(mddev),
2607                            bdevname(rdev->bdev, b),
2608                            (unsigned long long)r10_bio->sector);
2609         bio = bio_clone_mddev(r10_bio->master_bio,
2610                               GFP_NOIO, mddev);
2611         bio_trim(bio, r10_bio->sector - bio->bi_iter.bi_sector, max_sectors);
2612         r10_bio->devs[slot].bio = bio;
2613         r10_bio->devs[slot].rdev = rdev;
2614         bio->bi_iter.bi_sector = r10_bio->devs[slot].addr
2615                 + choose_data_offset(r10_bio, rdev);
2616         bio->bi_bdev = rdev->bdev;
2617         bio_set_op_attrs(bio, REQ_OP_READ, do_sync);
2618         if (test_bit(FailFast, &rdev->flags) &&
2619             test_bit(R10BIO_FailFast, &r10_bio->state))
2620                 bio->bi_opf |= MD_FAILFAST;
2621         bio->bi_private = r10_bio;
2622         bio->bi_end_io = raid10_end_read_request;
2623         trace_block_bio_remap(bdev_get_queue(bio->bi_bdev),
2624                               bio, bio_dev,
2625                               bio_last_sector - r10_bio->sectors);
2626
2627         if (max_sectors < r10_bio->sectors) {
2628                 /* Drat - have to split this up more */
2629                 struct bio *mbio = r10_bio->master_bio;
2630                 int sectors_handled =
2631                         r10_bio->sector + max_sectors
2632                         - mbio->bi_iter.bi_sector;
2633                 r10_bio->sectors = max_sectors;
2634                 spin_lock_irq(&conf->device_lock);
2635                 if (mbio->bi_phys_segments == 0)
2636                         mbio->bi_phys_segments = 2;
2637                 else
2638                         mbio->bi_phys_segments++;
2639                 spin_unlock_irq(&conf->device_lock);
2640                 generic_make_request(bio);
2641
2642                 r10_bio = mempool_alloc(conf->r10bio_pool,
2643                                         GFP_NOIO);
2644                 r10_bio->master_bio = mbio;
2645                 r10_bio->sectors = bio_sectors(mbio) - sectors_handled;
2646                 r10_bio->state = 0;
2647                 set_bit(R10BIO_ReadError,
2648                         &r10_bio->state);
2649                 r10_bio->mddev = mddev;
2650                 r10_bio->sector = mbio->bi_iter.bi_sector
2651                         + sectors_handled;
2652
2653                 goto read_more;
2654         } else
2655                 generic_make_request(bio);
2656 }
2657
2658 static void handle_write_completed(struct r10conf *conf, struct r10bio *r10_bio)
2659 {
2660         /* Some sort of write request has finished and it
2661          * succeeded in writing where we thought there was a
2662          * bad block.  So forget the bad block.
2663          * Or possibly if failed and we need to record
2664          * a bad block.
2665          */
2666         int m;
2667         struct md_rdev *rdev;
2668
2669         if (test_bit(R10BIO_IsSync, &r10_bio->state) ||
2670             test_bit(R10BIO_IsRecover, &r10_bio->state)) {
2671                 for (m = 0; m < conf->copies; m++) {
2672                         int dev = r10_bio->devs[m].devnum;
2673                         rdev = conf->mirrors[dev].rdev;
2674                         if (r10_bio->devs[m].bio == NULL)
2675                                 continue;
2676                         if (!r10_bio->devs[m].bio->bi_error) {
2677                                 rdev_clear_badblocks(
2678                                         rdev,
2679                                         r10_bio->devs[m].addr,
2680                                         r10_bio->sectors, 0);
2681                         } else {
2682                                 if (!rdev_set_badblocks(
2683                                             rdev,
2684                                             r10_bio->devs[m].addr,
2685                                             r10_bio->sectors, 0))
2686                                         md_error(conf->mddev, rdev);
2687                         }
2688                         rdev = conf->mirrors[dev].replacement;
2689                         if (r10_bio->devs[m].repl_bio == NULL)
2690                                 continue;
2691
2692                         if (!r10_bio->devs[m].repl_bio->bi_error) {
2693                                 rdev_clear_badblocks(
2694                                         rdev,
2695                                         r10_bio->devs[m].addr,
2696                                         r10_bio->sectors, 0);
2697                         } else {
2698                                 if (!rdev_set_badblocks(
2699                                             rdev,
2700                                             r10_bio->devs[m].addr,
2701                                             r10_bio->sectors, 0))
2702                                         md_error(conf->mddev, rdev);
2703                         }
2704                 }
2705                 put_buf(r10_bio);
2706         } else {
2707                 bool fail = false;
2708                 for (m = 0; m < conf->copies; m++) {
2709                         int dev = r10_bio->devs[m].devnum;
2710                         struct bio *bio = r10_bio->devs[m].bio;
2711                         rdev = conf->mirrors[dev].rdev;
2712                         if (bio == IO_MADE_GOOD) {
2713                                 rdev_clear_badblocks(
2714                                         rdev,
2715                                         r10_bio->devs[m].addr,
2716                                         r10_bio->sectors, 0);
2717                                 rdev_dec_pending(rdev, conf->mddev);
2718                         } else if (bio != NULL && bio->bi_error) {
2719                                 fail = true;
2720                                 if (!narrow_write_error(r10_bio, m)) {
2721                                         md_error(conf->mddev, rdev);
2722                                         set_bit(R10BIO_Degraded,
2723                                                 &r10_bio->state);
2724                                 }
2725                                 rdev_dec_pending(rdev, conf->mddev);
2726                         }
2727                         bio = r10_bio->devs[m].repl_bio;
2728                         rdev = conf->mirrors[dev].replacement;
2729                         if (rdev && bio == IO_MADE_GOOD) {
2730                                 rdev_clear_badblocks(
2731                                         rdev,
2732                                         r10_bio->devs[m].addr,
2733                                         r10_bio->sectors, 0);
2734                                 rdev_dec_pending(rdev, conf->mddev);
2735                         }
2736                 }
2737                 if (fail) {
2738                         spin_lock_irq(&conf->device_lock);
2739                         list_add(&r10_bio->retry_list, &conf->bio_end_io_list);
2740                         conf->nr_queued++;
2741                         spin_unlock_irq(&conf->device_lock);
2742                         md_wakeup_thread(conf->mddev->thread);
2743                 } else {
2744                         if (test_bit(R10BIO_WriteError,
2745                                      &r10_bio->state))
2746                                 close_write(r10_bio);
2747                         raid_end_bio_io(r10_bio);
2748                 }
2749         }
2750 }
2751
2752 static void raid10d(struct md_thread *thread)
2753 {
2754         struct mddev *mddev = thread->mddev;
2755         struct r10bio *r10_bio;
2756         unsigned long flags;
2757         struct r10conf *conf = mddev->private;
2758         struct list_head *head = &conf->retry_list;
2759         struct blk_plug plug;
2760
2761         md_check_recovery(mddev);
2762
2763         if (!list_empty_careful(&conf->bio_end_io_list) &&
2764             !test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags)) {
2765                 LIST_HEAD(tmp);
2766                 spin_lock_irqsave(&conf->device_lock, flags);
2767                 if (!test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags)) {
2768                         while (!list_empty(&conf->bio_end_io_list)) {
2769                                 list_move(conf->bio_end_io_list.prev, &tmp);
2770                                 conf->nr_queued--;
2771                         }
2772                 }
2773                 spin_unlock_irqrestore(&conf->device_lock, flags);
2774                 while (!list_empty(&tmp)) {
2775                         r10_bio = list_first_entry(&tmp, struct r10bio,
2776                                                    retry_list);
2777                         list_del(&r10_bio->retry_list);
2778                         if (mddev->degraded)
2779                                 set_bit(R10BIO_Degraded, &r10_bio->state);
2780
2781                         if (test_bit(R10BIO_WriteError,
2782                                      &r10_bio->state))
2783                                 close_write(r10_bio);
2784                         raid_end_bio_io(r10_bio);
2785                 }
2786         }
2787
2788         blk_start_plug(&plug);
2789         for (;;) {
2790
2791                 flush_pending_writes(conf);
2792
2793                 spin_lock_irqsave(&conf->device_lock, flags);
2794                 if (list_empty(head)) {
2795                         spin_unlock_irqrestore(&conf->device_lock, flags);
2796                         break;
2797                 }
2798                 r10_bio = list_entry(head->prev, struct r10bio, retry_list);
2799                 list_del(head->prev);
2800                 conf->nr_queued--;
2801                 spin_unlock_irqrestore(&conf->device_lock, flags);
2802
2803                 mddev = r10_bio->mddev;
2804                 conf = mddev->private;
2805                 if (test_bit(R10BIO_MadeGood, &r10_bio->state) ||
2806                     test_bit(R10BIO_WriteError, &r10_bio->state))
2807                         handle_write_completed(conf, r10_bio);
2808                 else if (test_bit(R10BIO_IsReshape, &r10_bio->state))
2809                         reshape_request_write(mddev, r10_bio);
2810                 else if (test_bit(R10BIO_IsSync, &r10_bio->state))
2811                         sync_request_write(mddev, r10_bio);
2812                 else if (test_bit(R10BIO_IsRecover, &r10_bio->state))
2813                         recovery_request_write(mddev, r10_bio);
2814                 else if (test_bit(R10BIO_ReadError, &r10_bio->state))
2815                         handle_read_error(mddev, r10_bio);
2816                 else {
2817                         /* just a partial read to be scheduled from a
2818                          * separate context
2819                          */
2820                         int slot = r10_bio->read_slot;
2821                         generic_make_request(r10_bio->devs[slot].bio);
2822                 }
2823
2824                 cond_resched();
2825                 if (mddev->sb_flags & ~(1<<MD_SB_CHANGE_PENDING))
2826                         md_check_recovery(mddev);
2827         }
2828         blk_finish_plug(&plug);
2829 }
2830
2831 static int init_resync(struct r10conf *conf)
2832 {
2833         int buffs;
2834         int i;
2835
2836         buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE;
2837         BUG_ON(conf->r10buf_pool);
2838         conf->have_replacement = 0;
2839         for (i = 0; i < conf->geo.raid_disks; i++)
2840                 if (conf->mirrors[i].replacement)
2841                         conf->have_replacement = 1;
2842         conf->r10buf_pool = mempool_create(buffs, r10buf_pool_alloc, r10buf_pool_free, conf);
2843         if (!conf->r10buf_pool)
2844                 return -ENOMEM;
2845         conf->next_resync = 0;
2846         return 0;
2847 }
2848
2849 /*
2850  * perform a "sync" on one "block"
2851  *
2852  * We need to make sure that no normal I/O request - particularly write
2853  * requests - conflict with active sync requests.
2854  *
2855  * This is achieved by tracking pending requests and a 'barrier' concept
2856  * that can be installed to exclude normal IO requests.
2857  *
2858  * Resync and recovery are handled very differently.
2859  * We differentiate by looking at MD_RECOVERY_SYNC in mddev->recovery.
2860  *
2861  * For resync, we iterate over virtual addresses, read all copies,
2862  * and update if there are differences.  If only one copy is live,
2863  * skip it.
2864  * For recovery, we iterate over physical addresses, read a good
2865  * value for each non-in_sync drive, and over-write.
2866  *
2867  * So, for recovery we may have several outstanding complex requests for a
2868  * given address, one for each out-of-sync device.  We model this by allocating
2869  * a number of r10_bio structures, one for each out-of-sync device.
2870  * As we setup these structures, we collect all bio's together into a list
2871  * which we then process collectively to add pages, and then process again
2872  * to pass to generic_make_request.
2873  *
2874  * The r10_bio structures are linked using a borrowed master_bio pointer.
2875  * This link is counted in ->remaining.  When the r10_bio that points to NULL
2876  * has its remaining count decremented to 0, the whole complex operation
2877  * is complete.
2878  *
2879  */
2880
2881 static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
2882                              int *skipped)
2883 {
2884         struct r10conf *conf = mddev->private;
2885         struct r10bio *r10_bio;
2886         struct bio *biolist = NULL, *bio;
2887         sector_t max_sector, nr_sectors;
2888         int i;
2889         int max_sync;
2890         sector_t sync_blocks;
2891         sector_t sectors_skipped = 0;
2892         int chunks_skipped = 0;
2893         sector_t chunk_mask = conf->geo.chunk_mask;
2894
2895         if (!conf->r10buf_pool)
2896                 if (init_resync(conf))
2897                         return 0;
2898
2899         /*
2900          * Allow skipping a full rebuild for incremental assembly
2901          * of a clean array, like RAID1 does.
2902          */
2903         if (mddev->bitmap == NULL &&
2904             mddev->recovery_cp == MaxSector &&
2905             mddev->reshape_position == MaxSector &&
2906             !test_bit(MD_RECOVERY_SYNC, &mddev->recovery) &&
2907             !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
2908             !test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
2909             conf->fullsync == 0) {
2910                 *skipped = 1;
2911                 return mddev->dev_sectors - sector_nr;
2912         }
2913
2914  skipped:
2915         max_sector = mddev->dev_sectors;
2916         if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) ||
2917             test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
2918                 max_sector = mddev->resync_max_sectors;
2919         if (sector_nr >= max_sector) {
2920                 /* If we aborted, we need to abort the
2921                  * sync on the 'current' bitmap chucks (there can
2922                  * be several when recovering multiple devices).
2923                  * as we may have started syncing it but not finished.
2924                  * We can find the current address in
2925                  * mddev->curr_resync, but for recovery,
2926                  * we need to convert that to several
2927                  * virtual addresses.
2928                  */
2929                 if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) {
2930                         end_reshape(conf);
2931                         close_sync(conf);
2932                         return 0;
2933                 }
2934
2935                 if (mddev->curr_resync < max_sector) { /* aborted */
2936                         if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery))
2937                                 bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
2938                                                 &sync_blocks, 1);
2939                         else for (i = 0; i < conf->geo.raid_disks; i++) {
2940                                 sector_t sect =
2941                                         raid10_find_virt(conf, mddev->curr_resync, i);
2942                                 bitmap_end_sync(mddev->bitmap, sect,
2943                                                 &sync_blocks, 1);
2944                         }
2945                 } else {
2946                         /* completed sync */
2947                         if ((!mddev->bitmap || conf->fullsync)
2948                             && conf->have_replacement
2949                             && test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
2950                                 /* Completed a full sync so the replacements
2951                                  * are now fully recovered.
2952                                  */
2953                                 rcu_read_lock();
2954                                 for (i = 0; i < conf->geo.raid_disks; i++) {
2955                                         struct md_rdev *rdev =
2956                                                 rcu_dereference(conf->mirrors[i].replacement);
2957                                         if (rdev)
2958                                                 rdev->recovery_offset = MaxSector;
2959                                 }
2960                                 rcu_read_unlock();
2961                         }
2962                         conf->fullsync = 0;
2963                 }
2964                 bitmap_close_sync(mddev->bitmap);
2965                 close_sync(conf);
2966                 *skipped = 1;
2967                 return sectors_skipped;
2968         }
2969
2970         if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
2971                 return reshape_request(mddev, sector_nr, skipped);
2972
2973         if (chunks_skipped >= conf->geo.raid_disks) {
2974                 /* if there has been nothing to do on any drive,
2975                  * then there is nothing to do at all..
2976                  */
2977                 *skipped = 1;
2978                 return (max_sector - sector_nr) + sectors_skipped;
2979         }
2980
2981         if (max_sector > mddev->resync_max)
2982                 max_sector = mddev->resync_max; /* Don't do IO beyond here */
2983
2984         /* make sure whole request will fit in a chunk - if chunks
2985          * are meaningful
2986          */
2987         if (conf->geo.near_copies < conf->geo.raid_disks &&
2988             max_sector > (sector_nr | chunk_mask))
2989                 max_sector = (sector_nr | chunk_mask) + 1;
2990
2991         /*
2992          * If there is non-resync activity waiting for a turn, then let it
2993          * though before starting on this new sync request.
2994          */
2995         if (conf->nr_waiting)
2996                 schedule_timeout_uninterruptible(1);
2997
2998         /* Again, very different code for resync and recovery.
2999          * Both must result in an r10bio with a list of bios that
3000          * have bi_end_io, bi_sector, bi_bdev set,
3001          * and bi_private set to the r10bio.
3002          * For recovery, we may actually create several r10bios
3003          * with 2 bios in each, that correspond to the bios in the main one.
3004          * In this case, the subordinate r10bios link back through a
3005          * borrowed master_bio pointer, and the counter in the master
3006          * includes a ref from each subordinate.
3007          */
3008         /* First, we decide what to do and set ->bi_end_io
3009          * To end_sync_read if we want to read, and
3010          * end_sync_write if we will want to write.
3011          */
3012
3013         max_sync = RESYNC_PAGES << (PAGE_SHIFT-9);
3014         if (!test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
3015                 /* recovery... the complicated one */
3016                 int j;
3017                 r10_bio = NULL;
3018
3019                 for (i = 0 ; i < conf->geo.raid_disks; i++) {
3020                         int still_degraded;
3021                         struct r10bio *rb2;
3022                         sector_t sect;
3023                         int must_sync;
3024                         int any_working;
3025                         struct raid10_info *mirror = &conf->mirrors[i];
3026                         struct md_rdev *mrdev, *mreplace;
3027
3028                         rcu_read_lock();
3029                         mrdev = rcu_dereference(mirror->rdev);
3030                         mreplace = rcu_dereference(mirror->replacement);
3031
3032                         if ((mrdev == NULL ||
3033                              test_bit(Faulty, &mrdev->flags) ||
3034                              test_bit(In_sync, &mrdev->flags)) &&
3035                             (mreplace == NULL ||
3036                              test_bit(Faulty, &mreplace->flags))) {
3037                                 rcu_read_unlock();
3038                                 continue;
3039                         }
3040
3041                         still_degraded = 0;
3042                         /* want to reconstruct this device */
3043                         rb2 = r10_bio;
3044                         sect = raid10_find_virt(conf, sector_nr, i);
3045                         if (sect >= mddev->resync_max_sectors) {
3046                                 /* last stripe is not complete - don't
3047                                  * try to recover this sector.
3048                                  */
3049                                 rcu_read_unlock();
3050                                 continue;
3051                         }
3052                         if (mreplace && test_bit(Faulty, &mreplace->flags))
3053                                 mreplace = NULL;
3054                         /* Unless we are doing a full sync, or a replacement
3055                          * we only need to recover the block if it is set in
3056                          * the bitmap
3057                          */
3058                         must_sync = bitmap_start_sync(mddev->bitmap, sect,
3059                                                       &sync_blocks, 1);
3060                         if (sync_blocks < max_sync)
3061                                 max_sync = sync_blocks;
3062                         if (!must_sync &&
3063                             mreplace == NULL &&
3064                             !conf->fullsync) {
3065                                 /* yep, skip the sync_blocks here, but don't assume
3066                                  * that there will never be anything to do here
3067                                  */
3068                                 chunks_skipped = -1;
3069                                 rcu_read_unlock();
3070                                 continue;
3071                         }
3072                         atomic_inc(&mrdev->nr_pending);
3073                         if (mreplace)
3074                                 atomic_inc(&mreplace->nr_pending);
3075                         rcu_read_unlock();
3076
3077                         r10_bio = mempool_alloc(conf->r10buf_pool, GFP_NOIO);
3078                         r10_bio->state = 0;
3079                         raise_barrier(conf, rb2 != NULL);
3080                         atomic_set(&r10_bio->remaining, 0);
3081
3082                         r10_bio->master_bio = (struct bio*)rb2;
3083                         if (rb2)
3084                                 atomic_inc(&rb2->remaining);
3085                         r10_bio->mddev = mddev;
3086                         set_bit(R10BIO_IsRecover, &r10_bio->state);
3087                         r10_bio->sector = sect;
3088
3089                         raid10_find_phys(conf, r10_bio);
3090
3091                         /* Need to check if the array will still be
3092                          * degraded
3093                          */
3094                         rcu_read_lock();
3095                         for (j = 0; j < conf->geo.raid_disks; j++) {
3096                                 struct md_rdev *rdev = rcu_dereference(
3097                                         conf->mirrors[j].rdev);
3098                                 if (rdev == NULL || test_bit(Faulty, &rdev->flags)) {
3099                                         still_degraded = 1;
3100                                         break;
3101                                 }
3102                         }
3103
3104                         must_sync = bitmap_start_sync(mddev->bitmap, sect,
3105                                                       &sync_blocks, still_degraded);
3106
3107                         any_working = 0;
3108                         for (j=0; j<conf->copies;j++) {
3109                                 int k;
3110                                 int d = r10_bio->devs[j].devnum;
3111                                 sector_t from_addr, to_addr;
3112                                 struct md_rdev *rdev =
3113                                         rcu_dereference(conf->mirrors[d].rdev);
3114                                 sector_t sector, first_bad;
3115                                 int bad_sectors;
3116                                 if (!rdev ||
3117                                     !test_bit(In_sync, &rdev->flags))
3118                                         continue;
3119                                 /* This is where we read from */
3120                                 any_working = 1;
3121                                 sector = r10_bio->devs[j].addr;
3122
3123                                 if (is_badblock(rdev, sector, max_sync,
3124                                                 &first_bad, &bad_sectors)) {
3125                                         if (first_bad > sector)
3126                                                 max_sync = first_bad - sector;
3127                                         else {
3128                                                 bad_sectors -= (sector
3129                                                                 - first_bad);
3130                                                 if (max_sync > bad_sectors)
3131                                                         max_sync = bad_sectors;
3132                                                 continue;
3133                                         }
3134                                 }
3135                                 bio = r10_bio->devs[0].bio;
3136                                 bio_reset(bio);
3137                                 bio->bi_next = biolist;
3138                                 biolist = bio;
3139                                 bio->bi_private = r10_bio;
3140                                 bio->bi_end_io = end_sync_read;
3141                                 bio_set_op_attrs(bio, REQ_OP_READ, 0);
3142                                 if (test_bit(FailFast, &rdev->flags))
3143                                         bio->bi_opf |= MD_FAILFAST;
3144                                 from_addr = r10_bio->devs[j].addr;
3145                                 bio->bi_iter.bi_sector = from_addr +
3146                                         rdev->data_offset;
3147                                 bio->bi_bdev = rdev->bdev;
3148                                 atomic_inc(&rdev->nr_pending);
3149                                 /* and we write to 'i' (if not in_sync) */
3150
3151                                 for (k=0; k<conf->copies; k++)
3152                                         if (r10_bio->devs[k].devnum == i)
3153                                                 break;
3154                                 BUG_ON(k == conf->copies);
3155                                 to_addr = r10_bio->devs[k].addr;
3156                                 r10_bio->devs[0].devnum = d;
3157                                 r10_bio->devs[0].addr = from_addr;
3158                                 r10_bio->devs[1].devnum = i;
3159                                 r10_bio->devs[1].addr = to_addr;
3160
3161                                 if (!test_bit(In_sync, &mrdev->flags)) {
3162                                         bio = r10_bio->devs[1].bio;
3163                                         bio_reset(bio);
3164                                         bio->bi_next = biolist;
3165                                         biolist = bio;
3166                                         bio->bi_private = r10_bio;
3167                                         bio->bi_end_io = end_sync_write;
3168                                         bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
3169                                         bio->bi_iter.bi_sector = to_addr
3170                                                 + mrdev->data_offset;
3171                                         bio->bi_bdev = mrdev->bdev;
3172                                         atomic_inc(&r10_bio->remaining);
3173                                 } else
3174                                         r10_bio->devs[1].bio->bi_end_io = NULL;
3175
3176                                 /* and maybe write to replacement */
3177                                 bio = r10_bio->devs[1].repl_bio;
3178                                 if (bio)
3179                                         bio->bi_end_io = NULL;
3180                                 /* Note: if mreplace != NULL, then bio
3181                                  * cannot be NULL as r10buf_pool_alloc will
3182                                  * have allocated it.
3183                                  * So the second test here is pointless.
3184                                  * But it keeps semantic-checkers happy, and
3185                                  * this comment keeps human reviewers
3186                                  * happy.
3187                                  */
3188                                 if (mreplace == NULL || bio == NULL ||
3189                                     test_bit(Faulty, &mreplace->flags))
3190                                         break;
3191                                 bio_reset(bio);
3192                                 bio->bi_next = biolist;
3193                                 biolist = bio;
3194                                 bio->bi_private = r10_bio;
3195                                 bio->bi_end_io = end_sync_write;
3196                                 bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
3197                                 bio->bi_iter.bi_sector = to_addr +
3198                                         mreplace->data_offset;
3199                                 bio->bi_bdev = mreplace->bdev;
3200                                 atomic_inc(&r10_bio->remaining);
3201                                 break;
3202                         }
3203                         rcu_read_unlock();
3204                         if (j == conf->copies) {
3205                                 /* Cannot recover, so abort the recovery or
3206                                  * record a bad block */
3207                                 if (any_working) {
3208                                         /* problem is that there are bad blocks
3209                                          * on other device(s)
3210                                          */
3211                                         int k;
3212                                         for (k = 0; k < conf->copies; k++)
3213                                                 if (r10_bio->devs[k].devnum == i)
3214                                                         break;
3215                                         if (!test_bit(In_sync,
3216                                                       &mrdev->flags)
3217                                             && !rdev_set_badblocks(
3218                                                     mrdev,
3219                                                     r10_bio->devs[k].addr,
3220                                                     max_sync, 0))
3221                                                 any_working = 0;
3222                                         if (mreplace &&
3223                                             !rdev_set_badblocks(
3224                                                     mreplace,
3225                                                     r10_bio->devs[k].addr,
3226                                                     max_sync, 0))
3227                                                 any_working = 0;
3228                                 }
3229                                 if (!any_working)  {
3230                                         if (!test_and_set_bit(MD_RECOVERY_INTR,
3231                                                               &mddev->recovery))
3232                                                 pr_warn("md/raid10:%s: insufficient working devices for recovery.\n",
3233                                                        mdname(mddev));
3234                                         mirror->recovery_disabled
3235                                                 = mddev->recovery_disabled;
3236                                 }
3237                                 put_buf(r10_bio);
3238                                 if (rb2)
3239                                         atomic_dec(&rb2->remaining);
3240                                 r10_bio = rb2;
3241                                 rdev_dec_pending(mrdev, mddev);
3242                                 if (mreplace)
3243                                         rdev_dec_pending(mreplace, mddev);
3244                                 break;
3245                         }
3246                         rdev_dec_pending(mrdev, mddev);
3247                         if (mreplace)
3248                                 rdev_dec_pending(mreplace, mddev);
3249                         if (r10_bio->devs[0].bio->bi_opf & MD_FAILFAST) {
3250                                 /* Only want this if there is elsewhere to
3251                                  * read from. 'j' is currently the first
3252                                  * readable copy.
3253                                  */
3254                                 int targets = 1;
3255                                 for (; j < conf->copies; j++) {
3256                                         int d = r10_bio->devs[j].devnum;
3257                                         if (conf->mirrors[d].rdev &&
3258                                             test_bit(In_sync,
3259                                                       &conf->mirrors[d].rdev->flags))
3260                                                 targets++;
3261                                 }
3262                                 if (targets == 1)
3263                                         r10_bio->devs[0].bio->bi_opf
3264                                                 &= ~MD_FAILFAST;
3265                         }
3266                 }
3267                 if (biolist == NULL) {
3268                         while (r10_bio) {
3269                                 struct r10bio *rb2 = r10_bio;
3270                                 r10_bio = (struct r10bio*) rb2->master_bio;
3271                                 rb2->master_bio = NULL;
3272                                 put_buf(rb2);
3273                         }
3274                         goto giveup;
3275                 }
3276         } else {
3277                 /* resync. Schedule a read for every block at this virt offset */
3278                 int count = 0;
3279
3280                 bitmap_cond_end_sync(mddev->bitmap, sector_nr, 0);
3281
3282                 if (!bitmap_start_sync(mddev->bitmap, sector_nr,
3283                                        &sync_blocks, mddev->degraded) &&
3284                     !conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED,
3285                                                  &mddev->recovery)) {
3286                         /* We can skip this block */
3287                         *skipped = 1;
3288                         return sync_blocks + sectors_skipped;
3289                 }
3290                 if (sync_blocks < max_sync)
3291                         max_sync = sync_blocks;
3292                 r10_bio = mempool_alloc(conf->r10buf_pool, GFP_NOIO);
3293                 r10_bio->state = 0;
3294
3295                 r10_bio->mddev = mddev;
3296                 atomic_set(&r10_bio->remaining, 0);
3297                 raise_barrier(conf, 0);
3298                 conf->next_resync = sector_nr;
3299
3300                 r10_bio->master_bio = NULL;
3301                 r10_bio->sector = sector_nr;
3302                 set_bit(R10BIO_IsSync, &r10_bio->state);
3303                 raid10_find_phys(conf, r10_bio);
3304                 r10_bio->sectors = (sector_nr | chunk_mask) - sector_nr + 1;
3305
3306                 for (i = 0; i < conf->copies; i++) {
3307                         int d = r10_bio->devs[i].devnum;
3308                         sector_t first_bad, sector;
3309                         int bad_sectors;
3310                         struct md_rdev *rdev;
3311
3312                         if (r10_bio->devs[i].repl_bio)
3313                                 r10_bio->devs[i].repl_bio->bi_end_io = NULL;
3314
3315                         bio = r10_bio->devs[i].bio;
3316                         bio_reset(bio);
3317                         bio->bi_error = -EIO;
3318                         rcu_read_lock();
3319                         rdev = rcu_dereference(conf->mirrors[d].rdev);
3320                         if (rdev == NULL || test_bit(Faulty, &rdev->flags)) {
3321                                 rcu_read_unlock();
3322                                 continue;
3323                         }
3324                         sector = r10_bio->devs[i].addr;
3325                         if (is_badblock(rdev, sector, max_sync,
3326                                         &first_bad, &bad_sectors)) {
3327                                 if (first_bad > sector)
3328                                         max_sync = first_bad - sector;
3329                                 else {
3330                                         bad_sectors -= (sector - first_bad);
3331                                         if (max_sync > bad_sectors)
3332                                                 max_sync = bad_sectors;
3333                                         rcu_read_unlock();
3334                                         continue;
3335                                 }
3336                         }
3337                         atomic_inc(&rdev->nr_pending);
3338                         atomic_inc(&r10_bio->remaining);
3339                         bio->bi_next = biolist;
3340                         biolist = bio;
3341                         bio->bi_private = r10_bio;
3342                         bio->bi_end_io = end_sync_read;
3343                         bio_set_op_attrs(bio, REQ_OP_READ, 0);
3344                         if (test_bit(FailFast, &conf->mirrors[d].rdev->flags))
3345                                 bio->bi_opf |= MD_FAILFAST;
3346                         bio->bi_iter.bi_sector = sector + rdev->data_offset;
3347                         bio->bi_bdev = rdev->bdev;
3348                         count++;
3349
3350                         rdev = rcu_dereference(conf->mirrors[d].replacement);
3351                         if (rdev == NULL || test_bit(Faulty, &rdev->flags)) {
3352                                 rcu_read_unlock();
3353                                 continue;
3354                         }
3355                         atomic_inc(&rdev->nr_pending);
3356                         rcu_read_unlock();
3357
3358                         /* Need to set up for writing to the replacement */
3359                         bio = r10_bio->devs[i].repl_bio;
3360                         bio_reset(bio);
3361                         bio->bi_error = -EIO;
3362
3363                         sector = r10_bio->devs[i].addr;
3364                         bio->bi_next = biolist;
3365                         biolist = bio;
3366                         bio->bi_private = r10_bio;
3367                         bio->bi_end_io = end_sync_write;
3368                         bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
3369                         if (test_bit(FailFast, &conf->mirrors[d].rdev->flags))
3370                                 bio->bi_opf |= MD_FAILFAST;
3371                         bio->bi_iter.bi_sector = sector + rdev->data_offset;
3372                         bio->bi_bdev = rdev->bdev;
3373                         count++;
3374                 }
3375
3376                 if (count < 2) {
3377                         for (i=0; i<conf->copies; i++) {
3378                                 int d = r10_bio->devs[i].devnum;
3379                                 if (r10_bio->devs[i].bio->bi_end_io)
3380                                         rdev_dec_pending(conf->mirrors[d].rdev,
3381                                                          mddev);
3382                                 if (r10_bio->devs[i].repl_bio &&
3383                                     r10_bio->devs[i].repl_bio->bi_end_io)
3384                                         rdev_dec_pending(
3385                                                 conf->mirrors[d].replacement,
3386                                                 mddev);
3387                         }
3388                         put_buf(r10_bio);
3389                         biolist = NULL;
3390                         goto giveup;
3391                 }
3392         }
3393
3394         nr_sectors = 0;
3395         if (sector_nr + max_sync < max_sector)
3396                 max_sector = sector_nr + max_sync;
3397         do {
3398                 struct page *page;
3399                 int len = PAGE_SIZE;
3400                 if (sector_nr + (len>>9) > max_sector)
3401                         len = (max_sector - sector_nr) << 9;
3402                 if (len == 0)
3403                         break;
3404                 for (bio= biolist ; bio ; bio=bio->bi_next) {
3405                         struct bio *bio2;
3406                         page = bio->bi_io_vec[bio->bi_vcnt].bv_page;
3407                         if (bio_add_page(bio, page, len, 0))
3408                                 continue;
3409
3410                         /* stop here */
3411                         bio->bi_io_vec[bio->bi_vcnt].bv_page = page;
3412                         for (bio2 = biolist;
3413                              bio2 && bio2 != bio;
3414                              bio2 = bio2->bi_next) {
3415                                 /* remove last page from this bio */
3416                                 bio2->bi_vcnt--;
3417                                 bio2->bi_iter.bi_size -= len;
3418                                 bio_clear_flag(bio2, BIO_SEG_VALID);
3419                         }
3420                         goto bio_full;
3421                 }
3422                 nr_sectors += len>>9;
3423                 sector_nr += len>>9;
3424         } while (biolist->bi_vcnt < RESYNC_PAGES);
3425  bio_full:
3426         r10_bio->sectors = nr_sectors;
3427
3428         while (biolist) {
3429                 bio = biolist;
3430                 biolist = biolist->bi_next;
3431
3432                 bio->bi_next = NULL;
3433                 r10_bio = bio->bi_private;
3434                 r10_bio->sectors = nr_sectors;
3435
3436                 if (bio->bi_end_io == end_sync_read) {
3437                         md_sync_acct(bio->bi_bdev, nr_sectors);
3438                         bio->bi_error = 0;
3439                         generic_make_request(bio);
3440                 }
3441         }
3442
3443         if (sectors_skipped)
3444                 /* pretend they weren't skipped, it makes
3445                  * no important difference in this case
3446                  */
3447                 md_done_sync(mddev, sectors_skipped, 1);
3448
3449         return sectors_skipped + nr_sectors;
3450  giveup:
3451         /* There is nowhere to write, so all non-sync
3452          * drives must be failed or in resync, all drives
3453          * have a bad block, so try the next chunk...
3454          */
3455         if (sector_nr + max_sync < max_sector)
3456                 max_sector = sector_nr + max_sync;
3457
3458         sectors_skipped += (max_sector - sector_nr);
3459         chunks_skipped ++;
3460         sector_nr = max_sector;
3461         goto skipped;
3462 }
3463
3464 static sector_t
3465 raid10_size(struct mddev *mddev, sector_t sectors, int raid_disks)
3466 {
3467         sector_t size;
3468         struct r10conf *conf = mddev->private;
3469
3470         if (!raid_disks)
3471                 raid_disks = min(conf->geo.raid_disks,
3472                                  conf->prev.raid_disks);
3473         if (!sectors)
3474                 sectors = conf->dev_sectors;
3475
3476         size = sectors >> conf->geo.chunk_shift;
3477         sector_div(size, conf->geo.far_copies);
3478         size = size * raid_disks;
3479         sector_div(size, conf->geo.near_copies);
3480
3481         return size << conf->geo.chunk_shift;
3482 }
3483
3484 static void calc_sectors(struct r10conf *conf, sector_t size)
3485 {
3486         /* Calculate the number of sectors-per-device that will
3487          * actually be used, and set conf->dev_sectors and
3488          * conf->stride
3489          */
3490
3491         size = size >> conf->geo.chunk_shift;
3492         sector_div(size, conf->geo.far_copies);
3493         size = size * conf->geo.raid_disks;
3494         sector_div(size, conf->geo.near_copies);
3495         /* 'size' is now the number of chunks in the array */
3496         /* calculate "used chunks per device" */
3497         size = size * conf->copies;
3498
3499         /* We need to round up when dividing by raid_disks to
3500          * get the stride size.
3501          */
3502         size = DIV_ROUND_UP_SECTOR_T(size, conf->geo.raid_disks);
3503
3504         conf->dev_sectors = size << conf->geo.chunk_shift;
3505
3506         if (conf->geo.far_offset)
3507                 conf->geo.stride = 1 << conf->geo.chunk_shift;
3508         else {
3509                 sector_div(size, conf->geo.far_copies);
3510                 conf->geo.stride = size << conf->geo.chunk_shift;
3511         }
3512 }
3513
3514 enum geo_type {geo_new, geo_old, geo_start};
3515 static int setup_geo(struct geom *geo, struct mddev *mddev, enum geo_type new)
3516 {
3517         int nc, fc, fo;
3518         int layout, chunk, disks;
3519         switch (new) {
3520         case geo_old:
3521                 layout = mddev->layout;
3522                 chunk = mddev->chunk_sectors;
3523                 disks = mddev->raid_disks - mddev->delta_disks;
3524                 break;
3525         case geo_new:
3526                 layout = mddev->new_layout;
3527                 chunk = mddev->new_chunk_sectors;
3528                 disks = mddev->raid_disks;
3529                 break;
3530         default: /* avoid 'may be unused' warnings */
3531         case geo_start: /* new when starting reshape - raid_disks not
3532                          * updated yet. */
3533                 layout = mddev->new_layout;
3534                 chunk = mddev->new_chunk_sectors;
3535                 disks = mddev->raid_disks + mddev->delta_disks;
3536                 break;
3537         }
3538         if (layout >> 19)
3539                 return -1;
3540         if (chunk < (PAGE_SIZE >> 9) ||
3541             !is_power_of_2(chunk))
3542                 return -2;
3543         nc = layout & 255;
3544         fc = (layout >> 8) & 255;
3545         fo = layout & (1<<16);
3546         geo->raid_disks = disks;
3547         geo->near_copies = nc;
3548         geo->far_copies = fc;
3549         geo->far_offset = fo;
3550         switch (layout >> 17) {
3551         case 0: /* original layout.  simple but not always optimal */
3552                 geo->far_set_size = disks;
3553                 break;
3554         case 1: /* "improved" layout which was buggy.  Hopefully no-one is
3555                  * actually using this, but leave code here just in case.*/
3556                 geo->far_set_size = disks/fc;
3557                 WARN(geo->far_set_size < fc,
3558                      "This RAID10 layout does not provide data safety - please backup and create new array\n");
3559                 break;
3560         case 2: /* "improved" layout fixed to match documentation */
3561                 geo->far_set_size = fc * nc;
3562                 break;
3563         default: /* Not a valid layout */
3564                 return -1;
3565         }
3566         geo->chunk_mask = chunk - 1;
3567         geo->chunk_shift = ffz(~chunk);
3568         return nc*fc;
3569 }
3570
3571 static struct r10conf *setup_conf(struct mddev *mddev)
3572 {
3573         struct r10conf *conf = NULL;
3574         int err = -EINVAL;
3575         struct geom geo;
3576         int copies;
3577
3578         copies = setup_geo(&geo, mddev, geo_new);
3579
3580         if (copies == -2) {
3581                 pr_warn("md/raid10:%s: chunk size must be at least PAGE_SIZE(%ld) and be a power of 2.\n",
3582                         mdname(mddev), PAGE_SIZE);
3583                 goto out;
3584         }
3585
3586         if (copies < 2 || copies > mddev->raid_disks) {
3587                 pr_warn("md/raid10:%s: unsupported raid10 layout: 0x%8x\n",
3588                         mdname(mddev), mddev->new_layout);
3589                 goto out;
3590         }
3591
3592         err = -ENOMEM;
3593         conf = kzalloc(sizeof(struct r10conf), GFP_KERNEL);
3594         if (!conf)
3595                 goto out;
3596
3597         /* FIXME calc properly */
3598         conf->mirrors = kzalloc(sizeof(struct raid10_info)*(mddev->raid_disks +
3599                                                             max(0,-mddev->delta_disks)),
3600                                 GFP_KERNEL);
3601         if (!conf->mirrors)
3602                 goto out;
3603
3604         conf->tmppage = alloc_page(GFP_KERNEL);
3605         if (!conf->tmppage)
3606                 goto out;
3607
3608         conf->geo = geo;
3609         conf->copies = copies;
3610         conf->r10bio_pool = mempool_create(NR_RAID10_BIOS, r10bio_pool_alloc,
3611                                            r10bio_pool_free, conf);
3612         if (!conf->r10bio_pool)
3613                 goto out;
3614
3615         calc_sectors(conf, mddev->dev_sectors);
3616         if (mddev->reshape_position == MaxSector) {
3617                 conf->prev = conf->geo;
3618                 conf->reshape_progress = MaxSector;
3619         } else {
3620                 if (setup_geo(&conf->prev, mddev, geo_old) != conf->copies) {
3621                         err = -EINVAL;
3622                         goto out;
3623                 }
3624                 conf->reshape_progress = mddev->reshape_position;
3625                 if (conf->prev.far_offset)
3626                         conf->prev.stride = 1 << conf->prev.chunk_shift;
3627                 else
3628                         /* far_copies must be 1 */
3629                         conf->prev.stride = conf->dev_sectors;
3630         }
3631         conf->reshape_safe = conf->reshape_progress;
3632         spin_lock_init(&conf->device_lock);
3633         INIT_LIST_HEAD(&conf->retry_list);
3634         INIT_LIST_HEAD(&conf->bio_end_io_list);
3635
3636         spin_lock_init(&conf->resync_lock);
3637         init_waitqueue_head(&conf->wait_barrier);
3638         atomic_set(&conf->nr_pending, 0);
3639
3640         conf->thread = md_register_thread(raid10d, mddev, "raid10");
3641         if (!conf->thread)
3642                 goto out;
3643
3644         conf->mddev = mddev;
3645         return conf;
3646
3647  out:
3648         if (conf) {
3649                 mempool_destroy(conf->r10bio_pool);
3650                 kfree(conf->mirrors);
3651                 safe_put_page(conf->tmppage);
3652                 kfree(conf);
3653         }
3654         return ERR_PTR(err);
3655 }
3656
3657 static int raid10_run(struct mddev *mddev)
3658 {
3659         struct r10conf *conf;
3660         int i, disk_idx, chunk_size;
3661         struct raid10_info *disk;
3662         struct md_rdev *rdev;
3663         sector_t size;
3664         sector_t min_offset_diff = 0;
3665         int first = 1;
3666         bool discard_supported = false;
3667
3668         if (mddev->private == NULL) {
3669                 conf = setup_conf(mddev);
3670                 if (IS_ERR(conf))
3671                         return PTR_ERR(conf);
3672                 mddev->private = conf;
3673         }
3674         conf = mddev->private;
3675         if (!conf)
3676                 goto out;
3677
3678         mddev->thread = conf->thread;
3679         conf->thread = NULL;
3680
3681         chunk_size = mddev->chunk_sectors << 9;
3682         if (mddev->queue) {
3683                 blk_queue_max_discard_sectors(mddev->queue,
3684                                               mddev->chunk_sectors);
3685                 blk_queue_max_write_same_sectors(mddev->queue, 0);
3686                 blk_queue_io_min(mddev->queue, chunk_size);
3687                 if (conf->geo.raid_disks % conf->geo.near_copies)
3688                         blk_queue_io_opt(mddev->queue, chunk_size * conf->geo.raid_disks);
3689                 else
3690                         blk_queue_io_opt(mddev->queue, chunk_size *
3691                                          (conf->geo.raid_disks / conf->geo.near_copies));
3692         }
3693
3694         rdev_for_each(rdev, mddev) {
3695                 long long diff;
3696                 struct request_queue *q;
3697
3698                 disk_idx = rdev->raid_disk;
3699                 if (disk_idx < 0)
3700                         continue;
3701                 if (disk_idx >= conf->geo.raid_disks &&
3702                     disk_idx >= conf->prev.raid_disks)
3703                         continue;
3704                 disk = conf->mirrors + disk_idx;
3705
3706                 if (test_bit(Replacement, &rdev->flags)) {
3707                         if (disk->replacement)
3708                                 goto out_free_conf;
3709                         disk->replacement = rdev;
3710                 } else {
3711                         if (disk->rdev)
3712                                 goto out_free_conf;
3713                         disk->rdev = rdev;
3714                 }
3715                 q = bdev_get_queue(rdev->bdev);
3716                 diff = (rdev->new_data_offset - rdev->data_offset);
3717                 if (!mddev->reshape_backwards)
3718                         diff = -diff;
3719                 if (diff < 0)
3720                         diff = 0;
3721                 if (first || diff < min_offset_diff)
3722                         min_offset_diff = diff;
3723
3724                 if (mddev->gendisk)
3725                         disk_stack_limits(mddev->gendisk, rdev->bdev,
3726                                           rdev->data_offset << 9);
3727
3728                 disk->head_position = 0;
3729
3730                 if (blk_queue_discard(bdev_get_queue(rdev->bdev)))
3731                         discard_supported = true;
3732         }
3733
3734         if (mddev->queue) {
3735                 if (discard_supported)
3736                         queue_flag_set_unlocked(QUEUE_FLAG_DISCARD,
3737                                                 mddev->queue);
3738                 else
3739                         queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD,
3740                                                   mddev->queue);
3741         }
3742         /* need to check that every block has at least one working mirror */
3743         if (!enough(conf, -1)) {
3744                 pr_err("md/raid10:%s: not enough operational mirrors.\n",
3745                        mdname(mddev));
3746                 goto out_free_conf;
3747         }
3748
3749         if (conf->reshape_progress != MaxSector) {
3750                 /* must ensure that shape change is supported */
3751                 if (conf->geo.far_copies != 1 &&
3752                     conf->geo.far_offset == 0)
3753                         goto out_free_conf;
3754                 if (conf->prev.far_copies != 1 &&
3755                     conf->prev.far_offset == 0)
3756                         goto out_free_conf;
3757         }
3758
3759         mddev->degraded = 0;
3760         for (i = 0;
3761              i < conf->geo.raid_disks
3762                      || i < conf->prev.raid_disks;
3763              i++) {
3764
3765                 disk = conf->mirrors + i;
3766
3767                 if (!disk->rdev && disk->replacement) {
3768                         /* The replacement is all we have - use it */
3769                         disk->rdev = disk->replacement;
3770                         disk->replacement = NULL;
3771                         clear_bit(Replacement, &disk->rdev->flags);
3772                 }
3773
3774                 if (!disk->rdev ||
3775                     !test_bit(In_sync, &disk->rdev->flags)) {
3776                         disk->head_position = 0;
3777                         mddev->degraded++;
3778                         if (disk->rdev &&
3779                             disk->rdev->saved_raid_disk < 0)
3780                                 conf->fullsync = 1;
3781                 }
3782                 disk->recovery_disabled = mddev->recovery_disabled - 1;
3783         }
3784
3785         if (mddev->recovery_cp != MaxSector)
3786                 pr_notice("md/raid10:%s: not clean -- starting background reconstruction\n",
3787                           mdname(mddev));
3788         pr_info("md/raid10:%s: active with %d out of %d devices\n",
3789                 mdname(mddev), conf->geo.raid_disks - mddev->degraded,
3790                 conf->geo.raid_disks);
3791         /*
3792          * Ok, everything is just fine now
3793          */
3794         mddev->dev_sectors = conf->dev_sectors;
3795         size = raid10_size(mddev, 0, 0);
3796         md_set_array_sectors(mddev, size);
3797         mddev->resync_max_sectors = size;
3798         set_bit(MD_FAILFAST_SUPPORTED, &mddev->flags);
3799
3800         if (mddev->queue) {
3801                 int stripe = conf->geo.raid_disks *
3802                         ((mddev->chunk_sectors << 9) / PAGE_SIZE);
3803
3804                 /* Calculate max read-ahead size.
3805                  * We need to readahead at least twice a whole stripe....
3806                  * maybe...
3807                  */
3808                 stripe /= conf->geo.near_copies;
3809                 if (mddev->queue->backing_dev_info.ra_pages < 2 * stripe)
3810                         mddev->queue->backing_dev_info.ra_pages = 2 * stripe;
3811         }
3812
3813         if (md_integrity_register(mddev))
3814                 goto out_free_conf;
3815
3816         if (conf->reshape_progress != MaxSector) {
3817                 unsigned long before_length, after_length;
3818
3819                 before_length = ((1 << conf->prev.chunk_shift) *
3820                                  conf->prev.far_copies);
3821                 after_length = ((1 << conf->geo.chunk_shift) *
3822                                 conf->geo.far_copies);
3823
3824                 if (max(before_length, after_length) > min_offset_diff) {
3825                         /* This cannot work */
3826                         pr_warn("md/raid10: offset difference not enough to continue reshape\n");
3827                         goto out_free_conf;
3828                 }
3829                 conf->offset_diff = min_offset_diff;
3830
3831                 clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
3832                 clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
3833                 set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
3834                 set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
3835                 mddev->sync_thread = md_register_thread(md_do_sync, mddev,
3836                                                         "reshape");
3837         }
3838
3839         return 0;
3840
3841 out_free_conf:
3842         md_unregister_thread(&mddev->thread);
3843         mempool_destroy(conf->r10bio_pool);
3844         safe_put_page(conf->tmppage);
3845         kfree(conf->mirrors);
3846         kfree(conf);
3847         mddev->private = NULL;
3848 out:
3849         return -EIO;
3850 }
3851
3852 static void raid10_free(struct mddev *mddev, void *priv)
3853 {
3854         struct r10conf *conf = priv;
3855
3856         mempool_destroy(conf->r10bio_pool);
3857         safe_put_page(conf->tmppage);
3858         kfree(conf->mirrors);
3859         kfree(conf->mirrors_old);
3860         kfree(conf->mirrors_new);
3861         kfree(conf);
3862 }
3863
3864 static void raid10_quiesce(struct mddev *mddev, int state)
3865 {
3866         struct r10conf *conf = mddev->private;
3867
3868         switch(state) {
3869         case 1:
3870                 raise_barrier(conf, 0);
3871                 break;
3872         case 0:
3873                 lower_barrier(conf);
3874                 break;
3875         }
3876 }
3877
3878 static int raid10_resize(struct mddev *mddev, sector_t sectors)
3879 {
3880         /* Resize of 'far' arrays is not supported.
3881          * For 'near' and 'offset' arrays we can set the
3882          * number of sectors used to be an appropriate multiple
3883          * of the chunk size.
3884          * For 'offset', this is far_copies*chunksize.
3885          * For 'near' the multiplier is the LCM of
3886          * near_copies and raid_disks.
3887          * So if far_copies > 1 && !far_offset, fail.
3888          * Else find LCM(raid_disks, near_copy)*far_copies and
3889          * multiply by chunk_size.  Then round to this number.
3890          * This is mostly done by raid10_size()
3891          */
3892         struct r10conf *conf = mddev->private;
3893         sector_t oldsize, size;
3894
3895         if (mddev->reshape_position != MaxSector)
3896                 return -EBUSY;
3897
3898         if (conf->geo.far_copies > 1 && !conf->geo.far_offset)
3899                 return -EINVAL;
3900
3901         oldsize = raid10_size(mddev, 0, 0);
3902         size = raid10_size(mddev, sectors, 0);
3903         if (mddev->external_size &&
3904             mddev->array_sectors > size)
3905                 return -EINVAL;
3906         if (mddev->bitmap) {
3907                 int ret = bitmap_resize(mddev->bitmap, size, 0, 0);
3908                 if (ret)
3909                         return ret;
3910         }
3911         md_set_array_sectors(mddev, size);
3912         if (mddev->queue) {
3913                 set_capacity(mddev->gendisk, mddev->array_sectors);
3914                 revalidate_disk(mddev->gendisk);
3915         }
3916         if (sectors > mddev->dev_sectors &&
3917             mddev->recovery_cp > oldsize) {
3918                 mddev->recovery_cp = oldsize;
3919                 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
3920         }
3921         calc_sectors(conf, sectors);
3922         mddev->dev_sectors = conf->dev_sectors;
3923         mddev->resync_max_sectors = size;
3924         return 0;
3925 }
3926
3927 static void *raid10_takeover_raid0(struct mddev *mddev, sector_t size, int devs)
3928 {
3929         struct md_rdev *rdev;
3930         struct r10conf *conf;
3931
3932         if (mddev->degraded > 0) {
3933                 pr_warn("md/raid10:%s: Error: degraded raid0!\n",
3934                         mdname(mddev));
3935                 return ERR_PTR(-EINVAL);
3936         }
3937         sector_div(size, devs);
3938
3939         /* Set new parameters */
3940         mddev->new_level = 10;
3941         /* new layout: far_copies = 1, near_copies = 2 */
3942         mddev->new_layout = (1<<8) + 2;
3943         mddev->new_chunk_sectors = mddev->chunk_sectors;
3944         mddev->delta_disks = mddev->raid_disks;
3945         mddev->raid_disks *= 2;
3946         /* make sure it will be not marked as dirty */
3947         mddev->recovery_cp = MaxSector;
3948         mddev->dev_sectors = size;
3949
3950         conf = setup_conf(mddev);
3951         if (!IS_ERR(conf)) {
3952                 rdev_for_each(rdev, mddev)
3953                         if (rdev->raid_disk >= 0) {
3954                                 rdev->new_raid_disk = rdev->raid_disk * 2;
3955                                 rdev->sectors = size;
3956                         }
3957                 conf->barrier = 1;
3958         }
3959
3960         return conf;
3961 }
3962
3963 static void *raid10_takeover(struct mddev *mddev)
3964 {
3965         struct r0conf *raid0_conf;
3966
3967         /* raid10 can take over:
3968          *  raid0 - providing it has only two drives
3969          */
3970         if (mddev->level == 0) {
3971                 /* for raid0 takeover only one zone is supported */
3972                 raid0_conf = mddev->private;
3973                 if (raid0_conf->nr_strip_zones > 1) {
3974                         pr_warn("md/raid10:%s: cannot takeover raid 0 with more than one zone.\n",
3975                                 mdname(mddev));
3976                         return ERR_PTR(-EINVAL);
3977                 }
3978                 return raid10_takeover_raid0(mddev,
3979                         raid0_conf->strip_zone->zone_end,
3980                         raid0_conf->strip_zone->nb_dev);
3981         }
3982         return ERR_PTR(-EINVAL);
3983 }
3984
3985 static int raid10_check_reshape(struct mddev *mddev)
3986 {
3987         /* Called when there is a request to change
3988          * - layout (to ->new_layout)
3989          * - chunk size (to ->new_chunk_sectors)
3990          * - raid_disks (by delta_disks)
3991          * or when trying to restart a reshape that was ongoing.
3992          *
3993          * We need to validate the request and possibly allocate
3994          * space if that might be an issue later.
3995          *
3996          * Currently we reject any reshape of a 'far' mode array,
3997          * allow chunk size to change if new is generally acceptable,
3998          * allow raid_disks to increase, and allow
3999          * a switch between 'near' mode and 'offset' mode.
4000          */
4001         struct r10conf *conf = mddev->private;
4002         struct geom geo;
4003
4004         if (conf->geo.far_copies != 1 && !conf->geo.far_offset)
4005                 return -EINVAL;
4006
4007         if (setup_geo(&geo, mddev, geo_start) != conf->copies)
4008                 /* mustn't change number of copies */
4009                 return -EINVAL;
4010         if (geo.far_copies > 1 && !geo.far_offset)
4011                 /* Cannot switch to 'far' mode */
4012                 return -EINVAL;
4013
4014         if (mddev->array_sectors & geo.chunk_mask)
4015                         /* not factor of array size */
4016                         return -EINVAL;
4017
4018         if (!enough(conf, -1))
4019                 return -EINVAL;
4020
4021         kfree(conf->mirrors_new);
4022         conf->mirrors_new = NULL;
4023         if (mddev->delta_disks > 0) {
4024                 /* allocate new 'mirrors' list */
4025                 conf->mirrors_new = kzalloc(
4026                         sizeof(struct raid10_info)
4027                         *(mddev->raid_disks +
4028                           mddev->delta_disks),
4029                         GFP_KERNEL);
4030                 if (!conf->mirrors_new)
4031                         return -ENOMEM;
4032         }
4033         return 0;
4034 }
4035
4036 /*
4037  * Need to check if array has failed when deciding whether to:
4038  *  - start an array
4039  *  - remove non-faulty devices
4040  *  - add a spare
4041  *  - allow a reshape
4042  * This determination is simple when no reshape is happening.
4043  * However if there is a reshape, we need to carefully check
4044  * both the before and after sections.
4045  * This is because some failed devices may only affect one
4046  * of the two sections, and some non-in_sync devices may
4047  * be insync in the section most affected by failed devices.
4048  */
4049 static int calc_degraded(struct r10conf *conf)
4050 {
4051         int degraded, degraded2;
4052         int i;
4053
4054         rcu_read_lock();
4055         degraded = 0;
4056         /* 'prev' section first */
4057         for (i = 0; i < conf->prev.raid_disks; i++) {
4058                 struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
4059                 if (!rdev || test_bit(Faulty, &rdev->flags))
4060                         degraded++;
4061                 else if (!test_bit(In_sync, &rdev->flags))
4062                         /* When we can reduce the number of devices in
4063                          * an array, this might not contribute to
4064                          * 'degraded'.  It does now.
4065                          */
4066                         degraded++;
4067         }
4068         rcu_read_unlock();
4069         if (conf->geo.raid_disks == conf->prev.raid_disks)
4070                 return degraded;
4071         rcu_read_lock();
4072         degraded2 = 0;
4073         for (i = 0; i < conf->geo.raid_disks; i++) {
4074                 struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
4075                 if (!rdev || test_bit(Faulty, &rdev->flags))
4076                         degraded2++;
4077                 else if (!test_bit(In_sync, &rdev->flags)) {
4078                         /* If reshape is increasing the number of devices,
4079                          * this section has already been recovered, so
4080                          * it doesn't contribute to degraded.
4081                          * else it does.
4082                          */
4083                         if (conf->geo.raid_disks <= conf->prev.raid_disks)
4084                                 degraded2++;
4085                 }
4086         }
4087         rcu_read_unlock();
4088         if (degraded2 > degraded)
4089                 return degraded2;
4090         return degraded;
4091 }
4092
4093 static int raid10_start_reshape(struct mddev *mddev)
4094 {
4095         /* A 'reshape' has been requested. This commits
4096          * the various 'new' fields and sets MD_RECOVER_RESHAPE
4097          * This also checks if there are enough spares and adds them
4098          * to the array.
4099          * We currently require enough spares to make the final
4100          * array non-degraded.  We also require that the difference
4101          * between old and new data_offset - on each device - is
4102          * enough that we never risk over-writing.
4103          */
4104
4105         unsigned long before_length, after_length;
4106         sector_t min_offset_diff = 0;
4107         int first = 1;
4108         struct geom new;
4109         struct r10conf *conf = mddev->private;
4110         struct md_rdev *rdev;
4111         int spares = 0;
4112         int ret;
4113
4114         if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
4115                 return -EBUSY;
4116
4117         if (setup_geo(&new, mddev, geo_start) != conf->copies)
4118                 return -EINVAL;
4119
4120         before_length = ((1 << conf->prev.chunk_shift) *
4121                          conf->prev.far_copies);
4122         after_length = ((1 << conf->geo.chunk_shift) *
4123                         conf->geo.far_copies);
4124
4125         rdev_for_each(rdev, mddev) {
4126                 if (!test_bit(In_sync, &rdev->flags)
4127                     && !test_bit(Faulty, &rdev->flags))
4128                         spares++;
4129                 if (rdev->raid_disk >= 0) {
4130                         long long diff = (rdev->new_data_offset
4131                                           - rdev->data_offset);
4132                         if (!mddev->reshape_backwards)
4133                                 diff = -diff;
4134                         if (diff < 0)
4135                                 diff = 0;
4136                         if (first || diff < min_offset_diff)
4137                                 min_offset_diff = diff;
4138                 }
4139         }
4140
4141         if (max(before_length, after_length) > min_offset_diff)
4142                 return -EINVAL;
4143
4144         if (spares < mddev->delta_disks)
4145                 return -EINVAL;
4146
4147         conf->offset_diff = min_offset_diff;
4148         spin_lock_irq(&conf->device_lock);
4149         if (conf->mirrors_new) {
4150                 memcpy(conf->mirrors_new, conf->mirrors,
4151                        sizeof(struct raid10_info)*conf->prev.raid_disks);
4152                 smp_mb();
4153                 kfree(conf->mirrors_old);
4154                 conf->mirrors_old = conf->mirrors;
4155                 conf->mirrors = conf->mirrors_new;
4156                 conf->mirrors_new = NULL;
4157         }
4158         setup_geo(&conf->geo, mddev, geo_start);
4159         smp_mb();
4160         if (mddev->reshape_backwards) {
4161                 sector_t size = raid10_size(mddev, 0, 0);
4162                 if (size < mddev->array_sectors) {
4163                         spin_unlock_irq(&conf->device_lock);
4164                         pr_warn("md/raid10:%s: array size must be reduce before number of disks\n",
4165                                 mdname(mddev));
4166                         return -EINVAL;
4167                 }
4168                 mddev->resync_max_sectors = size;
4169                 conf->reshape_progress = size;
4170         } else
4171                 conf->reshape_progress = 0;
4172         conf->reshape_safe = conf->reshape_progress;
4173         spin_unlock_irq(&conf->device_lock);
4174
4175         if (mddev->delta_disks && mddev->bitmap) {
4176                 ret = bitmap_resize(mddev->bitmap,
4177                                     raid10_size(mddev, 0,
4178                                                 conf->geo.raid_disks),
4179                                     0, 0);
4180                 if (ret)
4181                         goto abort;
4182         }
4183         if (mddev->delta_disks > 0) {
4184                 rdev_for_each(rdev, mddev)
4185                         if (rdev->raid_disk < 0 &&
4186                             !test_bit(Faulty, &rdev->flags)) {
4187                                 if (raid10_add_disk(mddev, rdev) == 0) {
4188                                         if (rdev->raid_disk >=
4189                                             conf->prev.raid_disks)
4190                                                 set_bit(In_sync, &rdev->flags);
4191                                         else
4192                                                 rdev->recovery_offset = 0;
4193
4194                                         if (sysfs_link_rdev(mddev, rdev))
4195                                                 /* Failure here  is OK */;
4196                                 }
4197                         } else if (rdev->raid_disk >= conf->prev.raid_disks
4198                                    && !test_bit(Faulty, &rdev->flags)) {
4199                                 /* This is a spare that was manually added */
4200                                 set_bit(In_sync, &rdev->flags);
4201                         }
4202         }
4203         /* When a reshape changes the number of devices,
4204          * ->degraded is measured against the larger of the
4205          * pre and  post numbers.
4206          */
4207         spin_lock_irq(&conf->device_lock);
4208         mddev->degraded = calc_degraded(conf);
4209         spin_unlock_irq(&conf->device_lock);
4210         mddev->raid_disks = conf->geo.raid_disks;
4211         mddev->reshape_position = conf->reshape_progress;
4212         set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
4213
4214         clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
4215         clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
4216         clear_bit(MD_RECOVERY_DONE, &mddev->recovery);
4217         set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
4218         set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
4219
4220         mddev->sync_thread = md_register_thread(md_do_sync, mddev,
4221                                                 "reshape");
4222         if (!mddev->sync_thread) {
4223                 ret = -EAGAIN;
4224                 goto abort;
4225         }
4226         conf->reshape_checkpoint = jiffies;
4227         md_wakeup_thread(mddev->sync_thread);
4228         md_new_event(mddev);
4229         return 0;
4230
4231 abort:
4232         mddev->recovery = 0;
4233         spin_lock_irq(&conf->device_lock);
4234         conf->geo = conf->prev;
4235         mddev->raid_disks = conf->geo.raid_disks;
4236         rdev_for_each(rdev, mddev)
4237                 rdev->new_data_offset = rdev->data_offset;
4238         smp_wmb();
4239         conf->reshape_progress = MaxSector;
4240         conf->reshape_safe = MaxSector;
4241         mddev->reshape_position = MaxSector;
4242         spin_unlock_irq(&conf->device_lock);
4243         return ret;
4244 }
4245
4246 /* Calculate the last device-address that could contain
4247  * any block from the chunk that includes the array-address 's'
4248  * and report the next address.
4249  * i.e. the address returned will be chunk-aligned and after
4250  * any data that is in the chunk containing 's'.
4251  */
4252 static sector_t last_dev_address(sector_t s, struct geom *geo)
4253 {
4254         s = (s | geo->chunk_mask) + 1;
4255         s >>= geo->chunk_shift;
4256         s *= geo->near_copies;
4257         s = DIV_ROUND_UP_SECTOR_T(s, geo->raid_disks);
4258         s *= geo->far_copies;
4259         s <<= geo->chunk_shift;
4260         return s;
4261 }
4262
4263 /* Calculate the first device-address that could contain
4264  * any block from the chunk that includes the array-address 's'.
4265  * This too will be the start of a chunk
4266  */
4267 static sector_t first_dev_address(sector_t s, struct geom *geo)
4268 {
4269         s >>= geo->chunk_shift;
4270         s *= geo->near_copies;
4271         sector_div(s, geo->raid_disks);
4272         s *= geo->far_copies;
4273         s <<= geo->chunk_shift;
4274         return s;
4275 }
4276
4277 static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr,
4278                                 int *skipped)
4279 {
4280         /* We simply copy at most one chunk (smallest of old and new)
4281          * at a time, possibly less if that exceeds RESYNC_PAGES,
4282          * or we hit a bad block or something.
4283          * This might mean we pause for normal IO in the middle of
4284          * a chunk, but that is not a problem as mddev->reshape_position
4285          * can record any location.
4286          *
4287          * If we will want to write to a location that isn't
4288          * yet recorded as 'safe' (i.e. in metadata on disk) then
4289          * we need to flush all reshape requests and update the metadata.
4290          *
4291          * When reshaping forwards (e.g. to more devices), we interpret
4292          * 'safe' as the earliest block which might not have been copied
4293          * down yet.  We divide this by previous stripe size and multiply
4294          * by previous stripe length to get lowest device offset that we
4295          * cannot write to yet.
4296          * We interpret 'sector_nr' as an address that we want to write to.
4297          * From this we use last_device_address() to find where we might
4298          * write to, and first_device_address on the  'safe' position.
4299          * If this 'next' write position is after the 'safe' position,
4300          * we must update the metadata to increase the 'safe' position.
4301          *
4302          * When reshaping backwards, we round in the opposite direction
4303          * and perform the reverse test:  next write position must not be
4304          * less than current safe position.
4305          *
4306          * In all this the minimum difference in data offsets
4307          * (conf->offset_diff - always positive) allows a bit of slack,
4308          * so next can be after 'safe', but not by more than offset_diff
4309          *
4310          * We need to prepare all the bios here before we start any IO
4311          * to ensure the size we choose is acceptable to all devices.
4312          * The means one for each copy for write-out and an extra one for
4313          * read-in.
4314          * We store the read-in bio in ->master_bio and the others in
4315          * ->devs[x].bio and ->devs[x].repl_bio.
4316          */
4317         struct r10conf *conf = mddev->private;
4318         struct r10bio *r10_bio;
4319         sector_t next, safe, last;
4320         int max_sectors;
4321         int nr_sectors;
4322         int s;
4323         struct md_rdev *rdev;
4324         int need_flush = 0;
4325         struct bio *blist;
4326         struct bio *bio, *read_bio;
4327         int sectors_done = 0;
4328
4329         if (sector_nr == 0) {
4330                 /* If restarting in the middle, skip the initial sectors */
4331                 if (mddev->reshape_backwards &&
4332                     conf->reshape_progress < raid10_size(mddev, 0, 0)) {
4333                         sector_nr = (raid10_size(mddev, 0, 0)
4334                                      - conf->reshape_progress);
4335                 } else if (!mddev->reshape_backwards &&
4336                            conf->reshape_progress > 0)
4337                         sector_nr = conf->reshape_progress;
4338                 if (sector_nr) {
4339                         mddev->curr_resync_completed = sector_nr;
4340                         sysfs_notify(&mddev->kobj, NULL, "sync_completed");
4341                         *skipped = 1;
4342                         return sector_nr;
4343                 }
4344         }
4345
4346         /* We don't use sector_nr to track where we are up to
4347          * as that doesn't work well for ->reshape_backwards.
4348          * So just use ->reshape_progress.
4349          */
4350         if (mddev->reshape_backwards) {
4351                 /* 'next' is the earliest device address that we might
4352                  * write to for this chunk in the new layout
4353                  */
4354                 next = first_dev_address(conf->reshape_progress - 1,
4355                                          &conf->geo);
4356
4357                 /* 'safe' is the last device address that we might read from
4358                  * in the old layout after a restart
4359                  */
4360                 safe = last_dev_address(conf->reshape_safe - 1,
4361                                         &conf->prev);
4362
4363                 if (next + conf->offset_diff < safe)
4364                         need_flush = 1;
4365
4366                 last = conf->reshape_progress - 1;
4367                 sector_nr = last & ~(sector_t)(conf->geo.chunk_mask
4368                                                & conf->prev.chunk_mask);
4369                 if (sector_nr + RESYNC_BLOCK_SIZE/512 < last)
4370                         sector_nr = last + 1 - RESYNC_BLOCK_SIZE/512;
4371         } else {
4372                 /* 'next' is after the last device address that we
4373                  * might write to for this chunk in the new layout
4374                  */
4375                 next = last_dev_address(conf->reshape_progress, &conf->geo);
4376
4377                 /* 'safe' is the earliest device address that we might
4378                  * read from in the old layout after a restart
4379                  */
4380                 safe = first_dev_address(conf->reshape_safe, &conf->prev);
4381
4382                 /* Need to update metadata if 'next' might be beyond 'safe'
4383                  * as that would possibly corrupt data
4384                  */
4385                 if (next > safe + conf->offset_diff)
4386                         need_flush = 1;
4387
4388                 sector_nr = conf->reshape_progress;
4389                 last  = sector_nr | (conf->geo.chunk_mask
4390                                      & conf->prev.chunk_mask);
4391
4392                 if (sector_nr + RESYNC_BLOCK_SIZE/512 <= last)
4393                         last = sector_nr + RESYNC_BLOCK_SIZE/512 - 1;
4394         }
4395
4396         if (need_flush ||
4397             time_after(jiffies, conf->reshape_checkpoint + 10*HZ)) {
4398                 /* Need to update reshape_position in metadata */
4399                 wait_barrier(conf);
4400                 mddev->reshape_position = conf->reshape_progress;
4401                 if (mddev->reshape_backwards)
4402                         mddev->curr_resync_completed = raid10_size(mddev, 0, 0)
4403                                 - conf->reshape_progress;
4404                 else
4405                         mddev->curr_resync_completed = conf->reshape_progress;
4406                 conf->reshape_checkpoint = jiffies;
4407                 set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
4408                 md_wakeup_thread(mddev->thread);
4409                 wait_event(mddev->sb_wait, mddev->sb_flags == 0 ||
4410                            test_bit(MD_RECOVERY_INTR, &mddev->recovery));
4411                 if (test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
4412                         allow_barrier(conf);
4413                         return sectors_done;
4414                 }
4415                 conf->reshape_safe = mddev->reshape_position;
4416                 allow_barrier(conf);
4417         }
4418
4419 read_more:
4420         /* Now schedule reads for blocks from sector_nr to last */
4421         r10_bio = mempool_alloc(conf->r10buf_pool, GFP_NOIO);
4422         r10_bio->state = 0;
4423         raise_barrier(conf, sectors_done != 0);
4424         atomic_set(&r10_bio->remaining, 0);
4425         r10_bio->mddev = mddev;
4426         r10_bio->sector = sector_nr;
4427         set_bit(R10BIO_IsReshape, &r10_bio->state);
4428         r10_bio->sectors = last - sector_nr + 1;
4429         rdev = read_balance(conf, r10_bio, &max_sectors);
4430         BUG_ON(!test_bit(R10BIO_Previous, &r10_bio->state));
4431
4432         if (!rdev) {
4433                 /* Cannot read from here, so need to record bad blocks
4434                  * on all the target devices.
4435                  */
4436                 // FIXME
4437                 mempool_free(r10_bio, conf->r10buf_pool);
4438                 set_bit(MD_RECOVERY_INTR, &mddev->recovery);
4439                 return sectors_done;
4440         }
4441
4442         read_bio = bio_alloc_mddev(GFP_KERNEL, RESYNC_PAGES, mddev);
4443
4444         read_bio->bi_bdev = rdev->bdev;
4445         read_bio->bi_iter.bi_sector = (r10_bio->devs[r10_bio->read_slot].addr
4446                                + rdev->data_offset);
4447         read_bio->bi_private = r10_bio;
4448         read_bio->bi_end_io = end_sync_read;
4449         bio_set_op_attrs(read_bio, REQ_OP_READ, 0);
4450         read_bio->bi_flags &= (~0UL << BIO_RESET_BITS);
4451         read_bio->bi_error = 0;
4452         read_bio->bi_vcnt = 0;
4453         read_bio->bi_iter.bi_size = 0;
4454         r10_bio->master_bio = read_bio;
4455         r10_bio->read_slot = r10_bio->devs[r10_bio->read_slot].devnum;
4456
4457         /* Now find the locations in the new layout */
4458         __raid10_find_phys(&conf->geo, r10_bio);
4459
4460         blist = read_bio;
4461         read_bio->bi_next = NULL;
4462
4463         rcu_read_lock();
4464         for (s = 0; s < conf->copies*2; s++) {
4465                 struct bio *b;
4466                 int d = r10_bio->devs[s/2].devnum;
4467                 struct md_rdev *rdev2;
4468                 if (s&1) {
4469                         rdev2 = rcu_dereference(conf->mirrors[d].replacement);
4470                         b = r10_bio->devs[s/2].repl_bio;
4471                 } else {
4472                         rdev2 = rcu_dereference(conf->mirrors[d].rdev);
4473                         b = r10_bio->devs[s/2].bio;
4474                 }
4475                 if (!rdev2 || test_bit(Faulty, &rdev2->flags))
4476                         continue;
4477
4478                 bio_reset(b);
4479                 b->bi_bdev = rdev2->bdev;
4480                 b->bi_iter.bi_sector = r10_bio->devs[s/2].addr +
4481                         rdev2->new_data_offset;
4482                 b->bi_private = r10_bio;
4483                 b->bi_end_io = end_reshape_write;
4484                 bio_set_op_attrs(b, REQ_OP_WRITE, 0);
4485                 b->bi_next = blist;
4486                 blist = b;
4487         }
4488
4489         /* Now add as many pages as possible to all of these bios. */
4490
4491         nr_sectors = 0;
4492         for (s = 0 ; s < max_sectors; s += PAGE_SIZE >> 9) {
4493                 struct page *page = r10_bio->devs[0].bio->bi_io_vec[s/(PAGE_SIZE>>9)].bv_page;
4494                 int len = (max_sectors - s) << 9;
4495                 if (len > PAGE_SIZE)
4496                         len = PAGE_SIZE;
4497                 for (bio = blist; bio ; bio = bio->bi_next) {
4498                         struct bio *bio2;
4499                         if (bio_add_page(bio, page, len, 0))
4500                                 continue;
4501
4502                         /* Didn't fit, must stop */
4503                         for (bio2 = blist;
4504                              bio2 && bio2 != bio;
4505                              bio2 = bio2->bi_next) {
4506                                 /* Remove last page from this bio */
4507                                 bio2->bi_vcnt--;
4508                                 bio2->bi_iter.bi_size -= len;
4509                                 bio_clear_flag(bio2, BIO_SEG_VALID);
4510                         }
4511                         goto bio_full;
4512                 }
4513                 sector_nr += len >> 9;
4514                 nr_sectors += len >> 9;
4515         }
4516 bio_full:
4517         rcu_read_unlock();
4518         r10_bio->sectors = nr_sectors;
4519
4520         /* Now submit the read */
4521         md_sync_acct(read_bio->bi_bdev, r10_bio->sectors);
4522         atomic_inc(&r10_bio->remaining);
4523         read_bio->bi_next = NULL;
4524         generic_make_request(read_bio);
4525         sector_nr += nr_sectors;
4526         sectors_done += nr_sectors;
4527         if (sector_nr <= last)
4528                 goto read_more;
4529
4530         /* Now that we have done the whole section we can
4531          * update reshape_progress
4532          */
4533         if (mddev->reshape_backwards)
4534                 conf->reshape_progress -= sectors_done;
4535         else
4536                 conf->reshape_progress += sectors_done;
4537
4538         return sectors_done;
4539 }
4540
4541 static void end_reshape_request(struct r10bio *r10_bio);
4542 static int handle_reshape_read_error(struct mddev *mddev,
4543                                      struct r10bio *r10_bio);
4544 static void reshape_request_write(struct mddev *mddev, struct r10bio *r10_bio)
4545 {
4546         /* Reshape read completed.  Hopefully we have a block
4547          * to write out.
4548          * If we got a read error then we do sync 1-page reads from
4549          * elsewhere until we find the data - or give up.
4550          */
4551         struct r10conf *conf = mddev->private;
4552         int s;
4553
4554         if (!test_bit(R10BIO_Uptodate, &r10_bio->state))
4555                 if (handle_reshape_read_error(mddev, r10_bio) < 0) {
4556                         /* Reshape has been aborted */
4557                         md_done_sync(mddev, r10_bio->sectors, 0);
4558                         return;
4559                 }
4560
4561         /* We definitely have the data in the pages, schedule the
4562          * writes.
4563          */
4564         atomic_set(&r10_bio->remaining, 1);
4565         for (s = 0; s < conf->copies*2; s++) {
4566                 struct bio *b;
4567                 int d = r10_bio->devs[s/2].devnum;
4568                 struct md_rdev *rdev;
4569                 rcu_read_lock();
4570                 if (s&1) {
4571                         rdev = rcu_dereference(conf->mirrors[d].replacement);
4572                         b = r10_bio->devs[s/2].repl_bio;
4573                 } else {
4574                         rdev = rcu_dereference(conf->mirrors[d].rdev);
4575                         b = r10_bio->devs[s/2].bio;
4576                 }
4577                 if (!rdev || test_bit(Faulty, &rdev->flags)) {
4578                         rcu_read_unlock();
4579                         continue;
4580                 }
4581                 atomic_inc(&rdev->nr_pending);
4582                 rcu_read_unlock();
4583                 md_sync_acct(b->bi_bdev, r10_bio->sectors);
4584                 atomic_inc(&r10_bio->remaining);
4585                 b->bi_next = NULL;
4586                 generic_make_request(b);
4587         }
4588         end_reshape_request(r10_bio);
4589 }
4590
4591 static void end_reshape(struct r10conf *conf)
4592 {
4593         if (test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery))
4594                 return;
4595
4596         spin_lock_irq(&conf->device_lock);
4597         conf->prev = conf->geo;
4598         md_finish_reshape(conf->mddev);
4599         smp_wmb();
4600         conf->reshape_progress = MaxSector;
4601         conf->reshape_safe = MaxSector;
4602         spin_unlock_irq(&conf->device_lock);
4603
4604         /* read-ahead size must cover two whole stripes, which is
4605          * 2 * (datadisks) * chunksize where 'n' is the number of raid devices
4606          */
4607         if (conf->mddev->queue) {
4608                 int stripe = conf->geo.raid_disks *
4609                         ((conf->mddev->chunk_sectors << 9) / PAGE_SIZE);
4610                 stripe /= conf->geo.near_copies;
4611                 if (conf->mddev->queue->backing_dev_info.ra_pages < 2 * stripe)
4612                         conf->mddev->queue->backing_dev_info.ra_pages = 2 * stripe;
4613         }
4614         conf->fullsync = 0;
4615 }
4616
4617 static int handle_reshape_read_error(struct mddev *mddev,
4618                                      struct r10bio *r10_bio)
4619 {
4620         /* Use sync reads to get the blocks from somewhere else */
4621         int sectors = r10_bio->sectors;
4622         struct r10conf *conf = mddev->private;
4623         struct {
4624                 struct r10bio r10_bio;
4625                 struct r10dev devs[conf->copies];
4626         } on_stack;
4627         struct r10bio *r10b = &on_stack.r10_bio;
4628         int slot = 0;
4629         int idx = 0;
4630         struct bio_vec *bvec = r10_bio->master_bio->bi_io_vec;
4631
4632         r10b->sector = r10_bio->sector;
4633         __raid10_find_phys(&conf->prev, r10b);
4634
4635         while (sectors) {
4636                 int s = sectors;
4637                 int success = 0;
4638                 int first_slot = slot;
4639
4640                 if (s > (PAGE_SIZE >> 9))
4641                         s = PAGE_SIZE >> 9;
4642
4643                 rcu_read_lock();
4644                 while (!success) {
4645                         int d = r10b->devs[slot].devnum;
4646                         struct md_rdev *rdev = rcu_dereference(conf->mirrors[d].rdev);
4647                         sector_t addr;
4648                         if (rdev == NULL ||
4649                             test_bit(Faulty, &rdev->flags) ||
4650                             !test_bit(In_sync, &rdev->flags))
4651                                 goto failed;
4652
4653                         addr = r10b->devs[slot].addr + idx * PAGE_SIZE;
4654                         atomic_inc(&rdev->nr_pending);
4655                         rcu_read_unlock();
4656                         success = sync_page_io(rdev,
4657                                                addr,
4658                                                s << 9,
4659                                                bvec[idx].bv_page,
4660                                                REQ_OP_READ, 0, false);
4661                         rdev_dec_pending(rdev, mddev);
4662                         rcu_read_lock();
4663                         if (success)
4664                                 break;
4665                 failed:
4666                         slot++;
4667                         if (slot >= conf->copies)
4668                                 slot = 0;
4669                         if (slot == first_slot)
4670                                 break;
4671                 }
4672                 rcu_read_unlock();
4673                 if (!success) {
4674                         /* couldn't read this block, must give up */
4675                         set_bit(MD_RECOVERY_INTR,
4676                                 &mddev->recovery);
4677                         return -EIO;
4678                 }
4679                 sectors -= s;
4680                 idx++;
4681         }
4682         return 0;
4683 }
4684
4685 static void end_reshape_write(struct bio *bio)
4686 {
4687         struct r10bio *r10_bio = bio->bi_private;
4688         struct mddev *mddev = r10_bio->mddev;
4689         struct r10conf *conf = mddev->private;
4690         int d;
4691         int slot;
4692         int repl;
4693         struct md_rdev *rdev = NULL;
4694
4695         d = find_bio_disk(conf, r10_bio, bio, &slot, &repl);
4696         if (repl)
4697                 rdev = conf->mirrors[d].replacement;
4698         if (!rdev) {
4699                 smp_mb();
4700                 rdev = conf->mirrors[d].rdev;
4701         }
4702
4703         if (bio->bi_error) {
4704                 /* FIXME should record badblock */
4705                 md_error(mddev, rdev);
4706         }
4707
4708         rdev_dec_pending(rdev, mddev);
4709         end_reshape_request(r10_bio);
4710 }
4711
4712 static void end_reshape_request(struct r10bio *r10_bio)
4713 {
4714         if (!atomic_dec_and_test(&r10_bio->remaining))
4715                 return;
4716         md_done_sync(r10_bio->mddev, r10_bio->sectors, 1);
4717         bio_put(r10_bio->master_bio);
4718         put_buf(r10_bio);
4719 }
4720
4721 static void raid10_finish_reshape(struct mddev *mddev)
4722 {
4723         struct r10conf *conf = mddev->private;
4724
4725         if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
4726                 return;
4727
4728         if (mddev->delta_disks > 0) {
4729                 sector_t size = raid10_size(mddev, 0, 0);
4730                 md_set_array_sectors(mddev, size);
4731                 if (mddev->recovery_cp > mddev->resync_max_sectors) {
4732                         mddev->recovery_cp = mddev->resync_max_sectors;
4733                         set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
4734                 }
4735                 mddev->resync_max_sectors = size;
4736                 if (mddev->queue) {
4737                         set_capacity(mddev->gendisk, mddev->array_sectors);
4738                         revalidate_disk(mddev->gendisk);
4739                 }
4740         } else {
4741                 int d;
4742                 rcu_read_lock();
4743                 for (d = conf->geo.raid_disks ;
4744                      d < conf->geo.raid_disks - mddev->delta_disks;
4745                      d++) {
4746                         struct md_rdev *rdev = rcu_dereference(conf->mirrors[d].rdev);
4747                         if (rdev)
4748                                 clear_bit(In_sync, &rdev->flags);
4749                         rdev = rcu_dereference(conf->mirrors[d].replacement);
4750                         if (rdev)
4751                                 clear_bit(In_sync, &rdev->flags);
4752                 }
4753                 rcu_read_unlock();
4754         }
4755         mddev->layout = mddev->new_layout;
4756         mddev->chunk_sectors = 1 << conf->geo.chunk_shift;
4757         mddev->reshape_position = MaxSector;
4758         mddev->delta_disks = 0;
4759         mddev->reshape_backwards = 0;
4760 }
4761
4762 static struct md_personality raid10_personality =
4763 {
4764         .name           = "raid10",
4765         .level          = 10,
4766         .owner          = THIS_MODULE,
4767         .make_request   = raid10_make_request,
4768         .run            = raid10_run,
4769         .free           = raid10_free,
4770         .status         = raid10_status,
4771         .error_handler  = raid10_error,
4772         .hot_add_disk   = raid10_add_disk,
4773         .hot_remove_disk= raid10_remove_disk,
4774         .spare_active   = raid10_spare_active,
4775         .sync_request   = raid10_sync_request,
4776         .quiesce        = raid10_quiesce,
4777         .size           = raid10_size,
4778         .resize         = raid10_resize,
4779         .takeover       = raid10_takeover,
4780         .check_reshape  = raid10_check_reshape,
4781         .start_reshape  = raid10_start_reshape,
4782         .finish_reshape = raid10_finish_reshape,
4783         .congested      = raid10_congested,
4784 };
4785
4786 static int __init raid_init(void)
4787 {
4788         return register_md_personality(&raid10_personality);
4789 }
4790
4791 static void raid_exit(void)
4792 {
4793         unregister_md_personality(&raid10_personality);
4794 }
4795
4796 module_init(raid_init);
4797 module_exit(raid_exit);
4798 MODULE_LICENSE("GPL");
4799 MODULE_DESCRIPTION("RAID10 (striped mirror) personality for MD");
4800 MODULE_ALIAS("md-personality-9"); /* RAID10 */
4801 MODULE_ALIAS("md-raid10");
4802 MODULE_ALIAS("md-level-10");
4803
4804 module_param(max_queued_requests, int, S_IRUGO|S_IWUSR);