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md: make it easier to wait for bad blocks to be acknowledged.
[mirror_ubuntu-hirsute-kernel.git] / drivers / md / raid1.c
1 /*
2 * raid1.c : Multiple Devices driver for Linux
3 *
4 * Copyright (C) 1999, 2000, 2001 Ingo Molnar, Red Hat
5 *
6 * Copyright (C) 1996, 1997, 1998 Ingo Molnar, Miguel de Icaza, Gadi Oxman
7 *
8 * RAID-1 management functions.
9 *
10 * Better read-balancing code written by Mika Kuoppala <miku@iki.fi>, 2000
11 *
12 * Fixes to reconstruction by Jakob Østergaard" <jakob@ostenfeld.dk>
13 * Various fixes by Neil Brown <neilb@cse.unsw.edu.au>
14 *
15 * Changes by Peter T. Breuer <ptb@it.uc3m.es> 31/1/2003 to support
16 * bitmapped intelligence in resync:
17 *
18 * - bitmap marked during normal i/o
19 * - bitmap used to skip nondirty blocks during sync
20 *
21 * Additions to bitmap code, (C) 2003-2004 Paul Clements, SteelEye Technology:
22 * - persistent bitmap code
23 *
24 * This program is free software; you can redistribute it and/or modify
25 * it under the terms of the GNU General Public License as published by
26 * the Free Software Foundation; either version 2, or (at your option)
27 * any later version.
28 *
29 * You should have received a copy of the GNU General Public License
30 * (for example /usr/src/linux/COPYING); if not, write to the Free
31 * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
32 */
33
34 #include <linux/slab.h>
35 #include <linux/delay.h>
36 #include <linux/blkdev.h>
37 #include <linux/seq_file.h>
38 #include <linux/ratelimit.h>
39 #include "md.h"
40 #include "raid1.h"
41 #include "bitmap.h"
42
43 #define DEBUG 0
44 #define PRINTK(x...) do { if (DEBUG) printk(x); } while (0)
45
46 /*
47 * Number of guaranteed r1bios in case of extreme VM load:
48 */
49 #define NR_RAID1_BIOS 256
50
51
52 static void allow_barrier(conf_t *conf);
53 static void lower_barrier(conf_t *conf);
54
55 static void * r1bio_pool_alloc(gfp_t gfp_flags, void *data)
56 {
57 struct pool_info *pi = data;
58 int size = offsetof(r1bio_t, bios[pi->raid_disks]);
59
60 /* allocate a r1bio with room for raid_disks entries in the bios array */
61 return kzalloc(size, gfp_flags);
62 }
63
64 static void r1bio_pool_free(void *r1_bio, void *data)
65 {
66 kfree(r1_bio);
67 }
68
69 #define RESYNC_BLOCK_SIZE (64*1024)
70 //#define RESYNC_BLOCK_SIZE PAGE_SIZE
71 #define RESYNC_SECTORS (RESYNC_BLOCK_SIZE >> 9)
72 #define RESYNC_PAGES ((RESYNC_BLOCK_SIZE + PAGE_SIZE-1) / PAGE_SIZE)
73 #define RESYNC_WINDOW (2048*1024)
74
75 static void * r1buf_pool_alloc(gfp_t gfp_flags, void *data)
76 {
77 struct pool_info *pi = data;
78 struct page *page;
79 r1bio_t *r1_bio;
80 struct bio *bio;
81 int i, j;
82
83 r1_bio = r1bio_pool_alloc(gfp_flags, pi);
84 if (!r1_bio)
85 return NULL;
86
87 /*
88 * Allocate bios : 1 for reading, n-1 for writing
89 */
90 for (j = pi->raid_disks ; j-- ; ) {
91 bio = bio_kmalloc(gfp_flags, RESYNC_PAGES);
92 if (!bio)
93 goto out_free_bio;
94 r1_bio->bios[j] = bio;
95 }
96 /*
97 * Allocate RESYNC_PAGES data pages and attach them to
98 * the first bio.
99 * If this is a user-requested check/repair, allocate
100 * RESYNC_PAGES for each bio.
101 */
102 if (test_bit(MD_RECOVERY_REQUESTED, &pi->mddev->recovery))
103 j = pi->raid_disks;
104 else
105 j = 1;
106 while(j--) {
107 bio = r1_bio->bios[j];
108 for (i = 0; i < RESYNC_PAGES; i++) {
109 page = alloc_page(gfp_flags);
110 if (unlikely(!page))
111 goto out_free_pages;
112
113 bio->bi_io_vec[i].bv_page = page;
114 bio->bi_vcnt = i+1;
115 }
116 }
117 /* If not user-requests, copy the page pointers to all bios */
118 if (!test_bit(MD_RECOVERY_REQUESTED, &pi->mddev->recovery)) {
119 for (i=0; i<RESYNC_PAGES ; i++)
120 for (j=1; j<pi->raid_disks; j++)
121 r1_bio->bios[j]->bi_io_vec[i].bv_page =
122 r1_bio->bios[0]->bi_io_vec[i].bv_page;
123 }
124
125 r1_bio->master_bio = NULL;
126
127 return r1_bio;
128
129 out_free_pages:
130 for (j=0 ; j < pi->raid_disks; j++)
131 for (i=0; i < r1_bio->bios[j]->bi_vcnt ; i++)
132 put_page(r1_bio->bios[j]->bi_io_vec[i].bv_page);
133 j = -1;
134 out_free_bio:
135 while ( ++j < pi->raid_disks )
136 bio_put(r1_bio->bios[j]);
137 r1bio_pool_free(r1_bio, data);
138 return NULL;
139 }
140
141 static void r1buf_pool_free(void *__r1_bio, void *data)
142 {
143 struct pool_info *pi = data;
144 int i,j;
145 r1bio_t *r1bio = __r1_bio;
146
147 for (i = 0; i < RESYNC_PAGES; i++)
148 for (j = pi->raid_disks; j-- ;) {
149 if (j == 0 ||
150 r1bio->bios[j]->bi_io_vec[i].bv_page !=
151 r1bio->bios[0]->bi_io_vec[i].bv_page)
152 safe_put_page(r1bio->bios[j]->bi_io_vec[i].bv_page);
153 }
154 for (i=0 ; i < pi->raid_disks; i++)
155 bio_put(r1bio->bios[i]);
156
157 r1bio_pool_free(r1bio, data);
158 }
159
160 static void put_all_bios(conf_t *conf, r1bio_t *r1_bio)
161 {
162 int i;
163
164 for (i = 0; i < conf->raid_disks; i++) {
165 struct bio **bio = r1_bio->bios + i;
166 if (*bio && *bio != IO_BLOCKED)
167 bio_put(*bio);
168 *bio = NULL;
169 }
170 }
171
172 static void free_r1bio(r1bio_t *r1_bio)
173 {
174 conf_t *conf = r1_bio->mddev->private;
175
176 put_all_bios(conf, r1_bio);
177 mempool_free(r1_bio, conf->r1bio_pool);
178 }
179
180 static void put_buf(r1bio_t *r1_bio)
181 {
182 conf_t *conf = r1_bio->mddev->private;
183 int i;
184
185 for (i=0; i<conf->raid_disks; i++) {
186 struct bio *bio = r1_bio->bios[i];
187 if (bio->bi_end_io)
188 rdev_dec_pending(conf->mirrors[i].rdev, r1_bio->mddev);
189 }
190
191 mempool_free(r1_bio, conf->r1buf_pool);
192
193 lower_barrier(conf);
194 }
195
196 static void reschedule_retry(r1bio_t *r1_bio)
197 {
198 unsigned long flags;
199 mddev_t *mddev = r1_bio->mddev;
200 conf_t *conf = mddev->private;
201
202 spin_lock_irqsave(&conf->device_lock, flags);
203 list_add(&r1_bio->retry_list, &conf->retry_list);
204 conf->nr_queued ++;
205 spin_unlock_irqrestore(&conf->device_lock, flags);
206
207 wake_up(&conf->wait_barrier);
208 md_wakeup_thread(mddev->thread);
209 }
210
211 /*
212 * raid_end_bio_io() is called when we have finished servicing a mirrored
213 * operation and are ready to return a success/failure code to the buffer
214 * cache layer.
215 */
216 static void call_bio_endio(r1bio_t *r1_bio)
217 {
218 struct bio *bio = r1_bio->master_bio;
219 int done;
220 conf_t *conf = r1_bio->mddev->private;
221
222 if (bio->bi_phys_segments) {
223 unsigned long flags;
224 spin_lock_irqsave(&conf->device_lock, flags);
225 bio->bi_phys_segments--;
226 done = (bio->bi_phys_segments == 0);
227 spin_unlock_irqrestore(&conf->device_lock, flags);
228 } else
229 done = 1;
230
231 if (!test_bit(R1BIO_Uptodate, &r1_bio->state))
232 clear_bit(BIO_UPTODATE, &bio->bi_flags);
233 if (done) {
234 bio_endio(bio, 0);
235 /*
236 * Wake up any possible resync thread that waits for the device
237 * to go idle.
238 */
239 allow_barrier(conf);
240 }
241 }
242
243 static void raid_end_bio_io(r1bio_t *r1_bio)
244 {
245 struct bio *bio = r1_bio->master_bio;
246
247 /* if nobody has done the final endio yet, do it now */
248 if (!test_and_set_bit(R1BIO_Returned, &r1_bio->state)) {
249 PRINTK(KERN_DEBUG "raid1: sync end %s on sectors %llu-%llu\n",
250 (bio_data_dir(bio) == WRITE) ? "write" : "read",
251 (unsigned long long) bio->bi_sector,
252 (unsigned long long) bio->bi_sector +
253 (bio->bi_size >> 9) - 1);
254
255 call_bio_endio(r1_bio);
256 }
257 free_r1bio(r1_bio);
258 }
259
260 /*
261 * Update disk head position estimator based on IRQ completion info.
262 */
263 static inline void update_head_pos(int disk, r1bio_t *r1_bio)
264 {
265 conf_t *conf = r1_bio->mddev->private;
266
267 conf->mirrors[disk].head_position =
268 r1_bio->sector + (r1_bio->sectors);
269 }
270
271 static void raid1_end_read_request(struct bio *bio, int error)
272 {
273 int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
274 r1bio_t *r1_bio = bio->bi_private;
275 int mirror;
276 conf_t *conf = r1_bio->mddev->private;
277
278 mirror = r1_bio->read_disk;
279 /*
280 * this branch is our 'one mirror IO has finished' event handler:
281 */
282 update_head_pos(mirror, r1_bio);
283
284 if (uptodate)
285 set_bit(R1BIO_Uptodate, &r1_bio->state);
286 else {
287 /* If all other devices have failed, we want to return
288 * the error upwards rather than fail the last device.
289 * Here we redefine "uptodate" to mean "Don't want to retry"
290 */
291 unsigned long flags;
292 spin_lock_irqsave(&conf->device_lock, flags);
293 if (r1_bio->mddev->degraded == conf->raid_disks ||
294 (r1_bio->mddev->degraded == conf->raid_disks-1 &&
295 !test_bit(Faulty, &conf->mirrors[mirror].rdev->flags)))
296 uptodate = 1;
297 spin_unlock_irqrestore(&conf->device_lock, flags);
298 }
299
300 if (uptodate)
301 raid_end_bio_io(r1_bio);
302 else {
303 /*
304 * oops, read error:
305 */
306 char b[BDEVNAME_SIZE];
307 printk_ratelimited(
308 KERN_ERR "md/raid1:%s: %s: "
309 "rescheduling sector %llu\n",
310 mdname(conf->mddev),
311 bdevname(conf->mirrors[mirror].rdev->bdev,
312 b),
313 (unsigned long long)r1_bio->sector);
314 set_bit(R1BIO_ReadError, &r1_bio->state);
315 reschedule_retry(r1_bio);
316 }
317
318 rdev_dec_pending(conf->mirrors[mirror].rdev, conf->mddev);
319 }
320
321 static void r1_bio_write_done(r1bio_t *r1_bio)
322 {
323 if (atomic_dec_and_test(&r1_bio->remaining))
324 {
325 /* it really is the end of this request */
326 if (test_bit(R1BIO_BehindIO, &r1_bio->state)) {
327 /* free extra copy of the data pages */
328 int i = r1_bio->behind_page_count;
329 while (i--)
330 safe_put_page(r1_bio->behind_pages[i]);
331 kfree(r1_bio->behind_pages);
332 r1_bio->behind_pages = NULL;
333 }
334 /* clear the bitmap if all writes complete successfully */
335 bitmap_endwrite(r1_bio->mddev->bitmap, r1_bio->sector,
336 r1_bio->sectors,
337 !test_bit(R1BIO_Degraded, &r1_bio->state),
338 test_bit(R1BIO_BehindIO, &r1_bio->state));
339 md_write_end(r1_bio->mddev);
340 raid_end_bio_io(r1_bio);
341 }
342 }
343
344 static void raid1_end_write_request(struct bio *bio, int error)
345 {
346 int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
347 r1bio_t *r1_bio = bio->bi_private;
348 int mirror, behind = test_bit(R1BIO_BehindIO, &r1_bio->state);
349 conf_t *conf = r1_bio->mddev->private;
350 struct bio *to_put = NULL;
351
352
353 for (mirror = 0; mirror < conf->raid_disks; mirror++)
354 if (r1_bio->bios[mirror] == bio)
355 break;
356
357 /*
358 * 'one mirror IO has finished' event handler:
359 */
360 r1_bio->bios[mirror] = NULL;
361 to_put = bio;
362 if (!uptodate) {
363 md_error(r1_bio->mddev, conf->mirrors[mirror].rdev);
364 /* an I/O failed, we can't clear the bitmap */
365 set_bit(R1BIO_Degraded, &r1_bio->state);
366 } else
367 /*
368 * Set R1BIO_Uptodate in our master bio, so that we
369 * will return a good error code for to the higher
370 * levels even if IO on some other mirrored buffer
371 * fails.
372 *
373 * The 'master' represents the composite IO operation
374 * to user-side. So if something waits for IO, then it
375 * will wait for the 'master' bio.
376 */
377 set_bit(R1BIO_Uptodate, &r1_bio->state);
378
379 update_head_pos(mirror, r1_bio);
380
381 if (behind) {
382 if (test_bit(WriteMostly, &conf->mirrors[mirror].rdev->flags))
383 atomic_dec(&r1_bio->behind_remaining);
384
385 /*
386 * In behind mode, we ACK the master bio once the I/O
387 * has safely reached all non-writemostly
388 * disks. Setting the Returned bit ensures that this
389 * gets done only once -- we don't ever want to return
390 * -EIO here, instead we'll wait
391 */
392 if (atomic_read(&r1_bio->behind_remaining) >= (atomic_read(&r1_bio->remaining)-1) &&
393 test_bit(R1BIO_Uptodate, &r1_bio->state)) {
394 /* Maybe we can return now */
395 if (!test_and_set_bit(R1BIO_Returned, &r1_bio->state)) {
396 struct bio *mbio = r1_bio->master_bio;
397 PRINTK(KERN_DEBUG "raid1: behind end write sectors %llu-%llu\n",
398 (unsigned long long) mbio->bi_sector,
399 (unsigned long long) mbio->bi_sector +
400 (mbio->bi_size >> 9) - 1);
401 call_bio_endio(r1_bio);
402 }
403 }
404 }
405 rdev_dec_pending(conf->mirrors[mirror].rdev, conf->mddev);
406
407 /*
408 * Let's see if all mirrored write operations have finished
409 * already.
410 */
411 r1_bio_write_done(r1_bio);
412
413 if (to_put)
414 bio_put(to_put);
415 }
416
417
418 /*
419 * This routine returns the disk from which the requested read should
420 * be done. There is a per-array 'next expected sequential IO' sector
421 * number - if this matches on the next IO then we use the last disk.
422 * There is also a per-disk 'last know head position' sector that is
423 * maintained from IRQ contexts, both the normal and the resync IO
424 * completion handlers update this position correctly. If there is no
425 * perfect sequential match then we pick the disk whose head is closest.
426 *
427 * If there are 2 mirrors in the same 2 devices, performance degrades
428 * because position is mirror, not device based.
429 *
430 * The rdev for the device selected will have nr_pending incremented.
431 */
432 static int read_balance(conf_t *conf, r1bio_t *r1_bio, int *max_sectors)
433 {
434 const sector_t this_sector = r1_bio->sector;
435 int sectors;
436 int best_good_sectors;
437 int start_disk;
438 int best_disk;
439 int i;
440 sector_t best_dist;
441 mdk_rdev_t *rdev;
442 int choose_first;
443
444 rcu_read_lock();
445 /*
446 * Check if we can balance. We can balance on the whole
447 * device if no resync is going on, or below the resync window.
448 * We take the first readable disk when above the resync window.
449 */
450 retry:
451 sectors = r1_bio->sectors;
452 best_disk = -1;
453 best_dist = MaxSector;
454 best_good_sectors = 0;
455
456 if (conf->mddev->recovery_cp < MaxSector &&
457 (this_sector + sectors >= conf->next_resync)) {
458 choose_first = 1;
459 start_disk = 0;
460 } else {
461 choose_first = 0;
462 start_disk = conf->last_used;
463 }
464
465 for (i = 0 ; i < conf->raid_disks ; i++) {
466 sector_t dist;
467 sector_t first_bad;
468 int bad_sectors;
469
470 int disk = start_disk + i;
471 if (disk >= conf->raid_disks)
472 disk -= conf->raid_disks;
473
474 rdev = rcu_dereference(conf->mirrors[disk].rdev);
475 if (r1_bio->bios[disk] == IO_BLOCKED
476 || rdev == NULL
477 || test_bit(Faulty, &rdev->flags))
478 continue;
479 if (!test_bit(In_sync, &rdev->flags) &&
480 rdev->recovery_offset < this_sector + sectors)
481 continue;
482 if (test_bit(WriteMostly, &rdev->flags)) {
483 /* Don't balance among write-mostly, just
484 * use the first as a last resort */
485 if (best_disk < 0)
486 best_disk = disk;
487 continue;
488 }
489 /* This is a reasonable device to use. It might
490 * even be best.
491 */
492 if (is_badblock(rdev, this_sector, sectors,
493 &first_bad, &bad_sectors)) {
494 if (best_dist < MaxSector)
495 /* already have a better device */
496 continue;
497 if (first_bad <= this_sector) {
498 /* cannot read here. If this is the 'primary'
499 * device, then we must not read beyond
500 * bad_sectors from another device..
501 */
502 bad_sectors -= (this_sector - first_bad);
503 if (choose_first && sectors > bad_sectors)
504 sectors = bad_sectors;
505 if (best_good_sectors > sectors)
506 best_good_sectors = sectors;
507
508 } else {
509 sector_t good_sectors = first_bad - this_sector;
510 if (good_sectors > best_good_sectors) {
511 best_good_sectors = good_sectors;
512 best_disk = disk;
513 }
514 if (choose_first)
515 break;
516 }
517 continue;
518 } else
519 best_good_sectors = sectors;
520
521 dist = abs(this_sector - conf->mirrors[disk].head_position);
522 if (choose_first
523 /* Don't change to another disk for sequential reads */
524 || conf->next_seq_sect == this_sector
525 || dist == 0
526 /* If device is idle, use it */
527 || atomic_read(&rdev->nr_pending) == 0) {
528 best_disk = disk;
529 break;
530 }
531 if (dist < best_dist) {
532 best_dist = dist;
533 best_disk = disk;
534 }
535 }
536
537 if (best_disk >= 0) {
538 rdev = rcu_dereference(conf->mirrors[best_disk].rdev);
539 if (!rdev)
540 goto retry;
541 atomic_inc(&rdev->nr_pending);
542 if (test_bit(Faulty, &rdev->flags)) {
543 /* cannot risk returning a device that failed
544 * before we inc'ed nr_pending
545 */
546 rdev_dec_pending(rdev, conf->mddev);
547 goto retry;
548 }
549 sectors = best_good_sectors;
550 conf->next_seq_sect = this_sector + sectors;
551 conf->last_used = best_disk;
552 }
553 rcu_read_unlock();
554 *max_sectors = sectors;
555
556 return best_disk;
557 }
558
559 int md_raid1_congested(mddev_t *mddev, int bits)
560 {
561 conf_t *conf = mddev->private;
562 int i, ret = 0;
563
564 rcu_read_lock();
565 for (i = 0; i < mddev->raid_disks; i++) {
566 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
567 if (rdev && !test_bit(Faulty, &rdev->flags)) {
568 struct request_queue *q = bdev_get_queue(rdev->bdev);
569
570 BUG_ON(!q);
571
572 /* Note the '|| 1' - when read_balance prefers
573 * non-congested targets, it can be removed
574 */
575 if ((bits & (1<<BDI_async_congested)) || 1)
576 ret |= bdi_congested(&q->backing_dev_info, bits);
577 else
578 ret &= bdi_congested(&q->backing_dev_info, bits);
579 }
580 }
581 rcu_read_unlock();
582 return ret;
583 }
584 EXPORT_SYMBOL_GPL(md_raid1_congested);
585
586 static int raid1_congested(void *data, int bits)
587 {
588 mddev_t *mddev = data;
589
590 return mddev_congested(mddev, bits) ||
591 md_raid1_congested(mddev, bits);
592 }
593
594 static void flush_pending_writes(conf_t *conf)
595 {
596 /* Any writes that have been queued but are awaiting
597 * bitmap updates get flushed here.
598 */
599 spin_lock_irq(&conf->device_lock);
600
601 if (conf->pending_bio_list.head) {
602 struct bio *bio;
603 bio = bio_list_get(&conf->pending_bio_list);
604 spin_unlock_irq(&conf->device_lock);
605 /* flush any pending bitmap writes to
606 * disk before proceeding w/ I/O */
607 bitmap_unplug(conf->mddev->bitmap);
608
609 while (bio) { /* submit pending writes */
610 struct bio *next = bio->bi_next;
611 bio->bi_next = NULL;
612 generic_make_request(bio);
613 bio = next;
614 }
615 } else
616 spin_unlock_irq(&conf->device_lock);
617 }
618
619 /* Barriers....
620 * Sometimes we need to suspend IO while we do something else,
621 * either some resync/recovery, or reconfigure the array.
622 * To do this we raise a 'barrier'.
623 * The 'barrier' is a counter that can be raised multiple times
624 * to count how many activities are happening which preclude
625 * normal IO.
626 * We can only raise the barrier if there is no pending IO.
627 * i.e. if nr_pending == 0.
628 * We choose only to raise the barrier if no-one is waiting for the
629 * barrier to go down. This means that as soon as an IO request
630 * is ready, no other operations which require a barrier will start
631 * until the IO request has had a chance.
632 *
633 * So: regular IO calls 'wait_barrier'. When that returns there
634 * is no backgroup IO happening, It must arrange to call
635 * allow_barrier when it has finished its IO.
636 * backgroup IO calls must call raise_barrier. Once that returns
637 * there is no normal IO happeing. It must arrange to call
638 * lower_barrier when the particular background IO completes.
639 */
640 #define RESYNC_DEPTH 32
641
642 static void raise_barrier(conf_t *conf)
643 {
644 spin_lock_irq(&conf->resync_lock);
645
646 /* Wait until no block IO is waiting */
647 wait_event_lock_irq(conf->wait_barrier, !conf->nr_waiting,
648 conf->resync_lock, );
649
650 /* block any new IO from starting */
651 conf->barrier++;
652
653 /* Now wait for all pending IO to complete */
654 wait_event_lock_irq(conf->wait_barrier,
655 !conf->nr_pending && conf->barrier < RESYNC_DEPTH,
656 conf->resync_lock, );
657
658 spin_unlock_irq(&conf->resync_lock);
659 }
660
661 static void lower_barrier(conf_t *conf)
662 {
663 unsigned long flags;
664 BUG_ON(conf->barrier <= 0);
665 spin_lock_irqsave(&conf->resync_lock, flags);
666 conf->barrier--;
667 spin_unlock_irqrestore(&conf->resync_lock, flags);
668 wake_up(&conf->wait_barrier);
669 }
670
671 static void wait_barrier(conf_t *conf)
672 {
673 spin_lock_irq(&conf->resync_lock);
674 if (conf->barrier) {
675 conf->nr_waiting++;
676 wait_event_lock_irq(conf->wait_barrier, !conf->barrier,
677 conf->resync_lock,
678 );
679 conf->nr_waiting--;
680 }
681 conf->nr_pending++;
682 spin_unlock_irq(&conf->resync_lock);
683 }
684
685 static void allow_barrier(conf_t *conf)
686 {
687 unsigned long flags;
688 spin_lock_irqsave(&conf->resync_lock, flags);
689 conf->nr_pending--;
690 spin_unlock_irqrestore(&conf->resync_lock, flags);
691 wake_up(&conf->wait_barrier);
692 }
693
694 static void freeze_array(conf_t *conf)
695 {
696 /* stop syncio and normal IO and wait for everything to
697 * go quite.
698 * We increment barrier and nr_waiting, and then
699 * wait until nr_pending match nr_queued+1
700 * This is called in the context of one normal IO request
701 * that has failed. Thus any sync request that might be pending
702 * will be blocked by nr_pending, and we need to wait for
703 * pending IO requests to complete or be queued for re-try.
704 * Thus the number queued (nr_queued) plus this request (1)
705 * must match the number of pending IOs (nr_pending) before
706 * we continue.
707 */
708 spin_lock_irq(&conf->resync_lock);
709 conf->barrier++;
710 conf->nr_waiting++;
711 wait_event_lock_irq(conf->wait_barrier,
712 conf->nr_pending == conf->nr_queued+1,
713 conf->resync_lock,
714 flush_pending_writes(conf));
715 spin_unlock_irq(&conf->resync_lock);
716 }
717 static void unfreeze_array(conf_t *conf)
718 {
719 /* reverse the effect of the freeze */
720 spin_lock_irq(&conf->resync_lock);
721 conf->barrier--;
722 conf->nr_waiting--;
723 wake_up(&conf->wait_barrier);
724 spin_unlock_irq(&conf->resync_lock);
725 }
726
727
728 /* duplicate the data pages for behind I/O
729 */
730 static void alloc_behind_pages(struct bio *bio, r1bio_t *r1_bio)
731 {
732 int i;
733 struct bio_vec *bvec;
734 struct page **pages = kzalloc(bio->bi_vcnt * sizeof(struct page*),
735 GFP_NOIO);
736 if (unlikely(!pages))
737 return;
738
739 bio_for_each_segment(bvec, bio, i) {
740 pages[i] = alloc_page(GFP_NOIO);
741 if (unlikely(!pages[i]))
742 goto do_sync_io;
743 memcpy(kmap(pages[i]) + bvec->bv_offset,
744 kmap(bvec->bv_page) + bvec->bv_offset, bvec->bv_len);
745 kunmap(pages[i]);
746 kunmap(bvec->bv_page);
747 }
748 r1_bio->behind_pages = pages;
749 r1_bio->behind_page_count = bio->bi_vcnt;
750 set_bit(R1BIO_BehindIO, &r1_bio->state);
751 return;
752
753 do_sync_io:
754 for (i = 0; i < bio->bi_vcnt; i++)
755 if (pages[i])
756 put_page(pages[i]);
757 kfree(pages);
758 PRINTK("%dB behind alloc failed, doing sync I/O\n", bio->bi_size);
759 }
760
761 static int make_request(mddev_t *mddev, struct bio * bio)
762 {
763 conf_t *conf = mddev->private;
764 mirror_info_t *mirror;
765 r1bio_t *r1_bio;
766 struct bio *read_bio;
767 int i, targets = 0, disks;
768 struct bitmap *bitmap;
769 unsigned long flags;
770 const int rw = bio_data_dir(bio);
771 const unsigned long do_sync = (bio->bi_rw & REQ_SYNC);
772 const unsigned long do_flush_fua = (bio->bi_rw & (REQ_FLUSH | REQ_FUA));
773 mdk_rdev_t *blocked_rdev;
774 int plugged;
775
776 /*
777 * Register the new request and wait if the reconstruction
778 * thread has put up a bar for new requests.
779 * Continue immediately if no resync is active currently.
780 */
781
782 md_write_start(mddev, bio); /* wait on superblock update early */
783
784 if (bio_data_dir(bio) == WRITE &&
785 bio->bi_sector + bio->bi_size/512 > mddev->suspend_lo &&
786 bio->bi_sector < mddev->suspend_hi) {
787 /* As the suspend_* range is controlled by
788 * userspace, we want an interruptible
789 * wait.
790 */
791 DEFINE_WAIT(w);
792 for (;;) {
793 flush_signals(current);
794 prepare_to_wait(&conf->wait_barrier,
795 &w, TASK_INTERRUPTIBLE);
796 if (bio->bi_sector + bio->bi_size/512 <= mddev->suspend_lo ||
797 bio->bi_sector >= mddev->suspend_hi)
798 break;
799 schedule();
800 }
801 finish_wait(&conf->wait_barrier, &w);
802 }
803
804 wait_barrier(conf);
805
806 bitmap = mddev->bitmap;
807
808 /*
809 * make_request() can abort the operation when READA is being
810 * used and no empty request is available.
811 *
812 */
813 r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
814
815 r1_bio->master_bio = bio;
816 r1_bio->sectors = bio->bi_size >> 9;
817 r1_bio->state = 0;
818 r1_bio->mddev = mddev;
819 r1_bio->sector = bio->bi_sector;
820
821 /* We might need to issue multiple reads to different
822 * devices if there are bad blocks around, so we keep
823 * track of the number of reads in bio->bi_phys_segments.
824 * If this is 0, there is only one r1_bio and no locking
825 * will be needed when requests complete. If it is
826 * non-zero, then it is the number of not-completed requests.
827 */
828 bio->bi_phys_segments = 0;
829 clear_bit(BIO_SEG_VALID, &bio->bi_flags);
830
831 if (rw == READ) {
832 /*
833 * read balancing logic:
834 */
835 int max_sectors;
836 int rdisk;
837
838 read_again:
839 rdisk = read_balance(conf, r1_bio, &max_sectors);
840
841 if (rdisk < 0) {
842 /* couldn't find anywhere to read from */
843 raid_end_bio_io(r1_bio);
844 return 0;
845 }
846 mirror = conf->mirrors + rdisk;
847
848 if (test_bit(WriteMostly, &mirror->rdev->flags) &&
849 bitmap) {
850 /* Reading from a write-mostly device must
851 * take care not to over-take any writes
852 * that are 'behind'
853 */
854 wait_event(bitmap->behind_wait,
855 atomic_read(&bitmap->behind_writes) == 0);
856 }
857 r1_bio->read_disk = rdisk;
858
859 read_bio = bio_clone_mddev(bio, GFP_NOIO, mddev);
860 md_trim_bio(read_bio, r1_bio->sector - bio->bi_sector,
861 max_sectors);
862
863 r1_bio->bios[rdisk] = read_bio;
864
865 read_bio->bi_sector = r1_bio->sector + mirror->rdev->data_offset;
866 read_bio->bi_bdev = mirror->rdev->bdev;
867 read_bio->bi_end_io = raid1_end_read_request;
868 read_bio->bi_rw = READ | do_sync;
869 read_bio->bi_private = r1_bio;
870
871 if (max_sectors < r1_bio->sectors) {
872 /* could not read all from this device, so we will
873 * need another r1_bio.
874 */
875 int sectors_handled;
876
877 sectors_handled = (r1_bio->sector + max_sectors
878 - bio->bi_sector);
879 r1_bio->sectors = max_sectors;
880 spin_lock_irq(&conf->device_lock);
881 if (bio->bi_phys_segments == 0)
882 bio->bi_phys_segments = 2;
883 else
884 bio->bi_phys_segments++;
885 spin_unlock_irq(&conf->device_lock);
886 /* Cannot call generic_make_request directly
887 * as that will be queued in __make_request
888 * and subsequent mempool_alloc might block waiting
889 * for it. So hand bio over to raid1d.
890 */
891 reschedule_retry(r1_bio);
892
893 r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
894
895 r1_bio->master_bio = bio;
896 r1_bio->sectors = (bio->bi_size >> 9) - sectors_handled;
897 r1_bio->state = 0;
898 r1_bio->mddev = mddev;
899 r1_bio->sector = bio->bi_sector + sectors_handled;
900 goto read_again;
901 } else
902 generic_make_request(read_bio);
903 return 0;
904 }
905
906 /*
907 * WRITE:
908 */
909 /* first select target devices under spinlock and
910 * inc refcount on their rdev. Record them by setting
911 * bios[x] to bio
912 */
913 plugged = mddev_check_plugged(mddev);
914
915 disks = conf->raid_disks;
916 retry_write:
917 blocked_rdev = NULL;
918 rcu_read_lock();
919 for (i = 0; i < disks; i++) {
920 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
921 if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) {
922 atomic_inc(&rdev->nr_pending);
923 blocked_rdev = rdev;
924 break;
925 }
926 if (rdev && !test_bit(Faulty, &rdev->flags)) {
927 atomic_inc(&rdev->nr_pending);
928 if (test_bit(Faulty, &rdev->flags)) {
929 rdev_dec_pending(rdev, mddev);
930 r1_bio->bios[i] = NULL;
931 } else {
932 r1_bio->bios[i] = bio;
933 targets++;
934 }
935 } else
936 r1_bio->bios[i] = NULL;
937 }
938 rcu_read_unlock();
939
940 if (unlikely(blocked_rdev)) {
941 /* Wait for this device to become unblocked */
942 int j;
943
944 for (j = 0; j < i; j++)
945 if (r1_bio->bios[j])
946 rdev_dec_pending(conf->mirrors[j].rdev, mddev);
947
948 allow_barrier(conf);
949 md_wait_for_blocked_rdev(blocked_rdev, mddev);
950 wait_barrier(conf);
951 goto retry_write;
952 }
953
954 if (targets < conf->raid_disks) {
955 /* array is degraded, we will not clear the bitmap
956 * on I/O completion (see raid1_end_write_request) */
957 set_bit(R1BIO_Degraded, &r1_bio->state);
958 }
959
960 /* do behind I/O ?
961 * Not if there are too many, or cannot allocate memory,
962 * or a reader on WriteMostly is waiting for behind writes
963 * to flush */
964 if (bitmap &&
965 (atomic_read(&bitmap->behind_writes)
966 < mddev->bitmap_info.max_write_behind) &&
967 !waitqueue_active(&bitmap->behind_wait))
968 alloc_behind_pages(bio, r1_bio);
969
970 atomic_set(&r1_bio->remaining, 1);
971 atomic_set(&r1_bio->behind_remaining, 0);
972
973 bitmap_startwrite(bitmap, bio->bi_sector, r1_bio->sectors,
974 test_bit(R1BIO_BehindIO, &r1_bio->state));
975 for (i = 0; i < disks; i++) {
976 struct bio *mbio;
977 if (!r1_bio->bios[i])
978 continue;
979
980 mbio = bio_clone_mddev(bio, GFP_NOIO, mddev);
981 r1_bio->bios[i] = mbio;
982
983 mbio->bi_sector = r1_bio->sector + conf->mirrors[i].rdev->data_offset;
984 mbio->bi_bdev = conf->mirrors[i].rdev->bdev;
985 mbio->bi_end_io = raid1_end_write_request;
986 mbio->bi_rw = WRITE | do_flush_fua | do_sync;
987 mbio->bi_private = r1_bio;
988
989 if (r1_bio->behind_pages) {
990 struct bio_vec *bvec;
991 int j;
992
993 /* Yes, I really want the '__' version so that
994 * we clear any unused pointer in the io_vec, rather
995 * than leave them unchanged. This is important
996 * because when we come to free the pages, we won't
997 * know the original bi_idx, so we just free
998 * them all
999 */
1000 __bio_for_each_segment(bvec, mbio, j, 0)
1001 bvec->bv_page = r1_bio->behind_pages[j];
1002 if (test_bit(WriteMostly, &conf->mirrors[i].rdev->flags))
1003 atomic_inc(&r1_bio->behind_remaining);
1004 }
1005
1006 atomic_inc(&r1_bio->remaining);
1007 spin_lock_irqsave(&conf->device_lock, flags);
1008 bio_list_add(&conf->pending_bio_list, mbio);
1009 spin_unlock_irqrestore(&conf->device_lock, flags);
1010 }
1011 r1_bio_write_done(r1_bio);
1012
1013 /* In case raid1d snuck in to freeze_array */
1014 wake_up(&conf->wait_barrier);
1015
1016 if (do_sync || !bitmap || !plugged)
1017 md_wakeup_thread(mddev->thread);
1018
1019 return 0;
1020 }
1021
1022 static void status(struct seq_file *seq, mddev_t *mddev)
1023 {
1024 conf_t *conf = mddev->private;
1025 int i;
1026
1027 seq_printf(seq, " [%d/%d] [", conf->raid_disks,
1028 conf->raid_disks - mddev->degraded);
1029 rcu_read_lock();
1030 for (i = 0; i < conf->raid_disks; i++) {
1031 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
1032 seq_printf(seq, "%s",
1033 rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_");
1034 }
1035 rcu_read_unlock();
1036 seq_printf(seq, "]");
1037 }
1038
1039
1040 static void error(mddev_t *mddev, mdk_rdev_t *rdev)
1041 {
1042 char b[BDEVNAME_SIZE];
1043 conf_t *conf = mddev->private;
1044
1045 /*
1046 * If it is not operational, then we have already marked it as dead
1047 * else if it is the last working disks, ignore the error, let the
1048 * next level up know.
1049 * else mark the drive as failed
1050 */
1051 if (test_bit(In_sync, &rdev->flags)
1052 && (conf->raid_disks - mddev->degraded) == 1) {
1053 /*
1054 * Don't fail the drive, act as though we were just a
1055 * normal single drive.
1056 * However don't try a recovery from this drive as
1057 * it is very likely to fail.
1058 */
1059 conf->recovery_disabled = mddev->recovery_disabled;
1060 return;
1061 }
1062 set_bit(Blocked, &rdev->flags);
1063 if (test_and_clear_bit(In_sync, &rdev->flags)) {
1064 unsigned long flags;
1065 spin_lock_irqsave(&conf->device_lock, flags);
1066 mddev->degraded++;
1067 set_bit(Faulty, &rdev->flags);
1068 spin_unlock_irqrestore(&conf->device_lock, flags);
1069 /*
1070 * if recovery is running, make sure it aborts.
1071 */
1072 set_bit(MD_RECOVERY_INTR, &mddev->recovery);
1073 } else
1074 set_bit(Faulty, &rdev->flags);
1075 set_bit(MD_CHANGE_DEVS, &mddev->flags);
1076 printk(KERN_ALERT
1077 "md/raid1:%s: Disk failure on %s, disabling device.\n"
1078 "md/raid1:%s: Operation continuing on %d devices.\n",
1079 mdname(mddev), bdevname(rdev->bdev, b),
1080 mdname(mddev), conf->raid_disks - mddev->degraded);
1081 }
1082
1083 static void print_conf(conf_t *conf)
1084 {
1085 int i;
1086
1087 printk(KERN_DEBUG "RAID1 conf printout:\n");
1088 if (!conf) {
1089 printk(KERN_DEBUG "(!conf)\n");
1090 return;
1091 }
1092 printk(KERN_DEBUG " --- wd:%d rd:%d\n", conf->raid_disks - conf->mddev->degraded,
1093 conf->raid_disks);
1094
1095 rcu_read_lock();
1096 for (i = 0; i < conf->raid_disks; i++) {
1097 char b[BDEVNAME_SIZE];
1098 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
1099 if (rdev)
1100 printk(KERN_DEBUG " disk %d, wo:%d, o:%d, dev:%s\n",
1101 i, !test_bit(In_sync, &rdev->flags),
1102 !test_bit(Faulty, &rdev->flags),
1103 bdevname(rdev->bdev,b));
1104 }
1105 rcu_read_unlock();
1106 }
1107
1108 static void close_sync(conf_t *conf)
1109 {
1110 wait_barrier(conf);
1111 allow_barrier(conf);
1112
1113 mempool_destroy(conf->r1buf_pool);
1114 conf->r1buf_pool = NULL;
1115 }
1116
1117 static int raid1_spare_active(mddev_t *mddev)
1118 {
1119 int i;
1120 conf_t *conf = mddev->private;
1121 int count = 0;
1122 unsigned long flags;
1123
1124 /*
1125 * Find all failed disks within the RAID1 configuration
1126 * and mark them readable.
1127 * Called under mddev lock, so rcu protection not needed.
1128 */
1129 for (i = 0; i < conf->raid_disks; i++) {
1130 mdk_rdev_t *rdev = conf->mirrors[i].rdev;
1131 if (rdev
1132 && !test_bit(Faulty, &rdev->flags)
1133 && !test_and_set_bit(In_sync, &rdev->flags)) {
1134 count++;
1135 sysfs_notify_dirent_safe(rdev->sysfs_state);
1136 }
1137 }
1138 spin_lock_irqsave(&conf->device_lock, flags);
1139 mddev->degraded -= count;
1140 spin_unlock_irqrestore(&conf->device_lock, flags);
1141
1142 print_conf(conf);
1143 return count;
1144 }
1145
1146
1147 static int raid1_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
1148 {
1149 conf_t *conf = mddev->private;
1150 int err = -EEXIST;
1151 int mirror = 0;
1152 mirror_info_t *p;
1153 int first = 0;
1154 int last = mddev->raid_disks - 1;
1155
1156 if (mddev->recovery_disabled == conf->recovery_disabled)
1157 return -EBUSY;
1158
1159 if (rdev->raid_disk >= 0)
1160 first = last = rdev->raid_disk;
1161
1162 for (mirror = first; mirror <= last; mirror++)
1163 if ( !(p=conf->mirrors+mirror)->rdev) {
1164
1165 disk_stack_limits(mddev->gendisk, rdev->bdev,
1166 rdev->data_offset << 9);
1167 /* as we don't honour merge_bvec_fn, we must
1168 * never risk violating it, so limit
1169 * ->max_segments to one lying with a single
1170 * page, as a one page request is never in
1171 * violation.
1172 */
1173 if (rdev->bdev->bd_disk->queue->merge_bvec_fn) {
1174 blk_queue_max_segments(mddev->queue, 1);
1175 blk_queue_segment_boundary(mddev->queue,
1176 PAGE_CACHE_SIZE - 1);
1177 }
1178
1179 p->head_position = 0;
1180 rdev->raid_disk = mirror;
1181 err = 0;
1182 /* As all devices are equivalent, we don't need a full recovery
1183 * if this was recently any drive of the array
1184 */
1185 if (rdev->saved_raid_disk < 0)
1186 conf->fullsync = 1;
1187 rcu_assign_pointer(p->rdev, rdev);
1188 break;
1189 }
1190 md_integrity_add_rdev(rdev, mddev);
1191 print_conf(conf);
1192 return err;
1193 }
1194
1195 static int raid1_remove_disk(mddev_t *mddev, int number)
1196 {
1197 conf_t *conf = mddev->private;
1198 int err = 0;
1199 mdk_rdev_t *rdev;
1200 mirror_info_t *p = conf->mirrors+ number;
1201
1202 print_conf(conf);
1203 rdev = p->rdev;
1204 if (rdev) {
1205 if (test_bit(In_sync, &rdev->flags) ||
1206 atomic_read(&rdev->nr_pending)) {
1207 err = -EBUSY;
1208 goto abort;
1209 }
1210 /* Only remove non-faulty devices if recovery
1211 * is not possible.
1212 */
1213 if (!test_bit(Faulty, &rdev->flags) &&
1214 mddev->recovery_disabled != conf->recovery_disabled &&
1215 mddev->degraded < conf->raid_disks) {
1216 err = -EBUSY;
1217 goto abort;
1218 }
1219 p->rdev = NULL;
1220 synchronize_rcu();
1221 if (atomic_read(&rdev->nr_pending)) {
1222 /* lost the race, try later */
1223 err = -EBUSY;
1224 p->rdev = rdev;
1225 goto abort;
1226 }
1227 err = md_integrity_register(mddev);
1228 }
1229 abort:
1230
1231 print_conf(conf);
1232 return err;
1233 }
1234
1235
1236 static void end_sync_read(struct bio *bio, int error)
1237 {
1238 r1bio_t *r1_bio = bio->bi_private;
1239 int i;
1240
1241 for (i=r1_bio->mddev->raid_disks; i--; )
1242 if (r1_bio->bios[i] == bio)
1243 break;
1244 BUG_ON(i < 0);
1245 update_head_pos(i, r1_bio);
1246 /*
1247 * we have read a block, now it needs to be re-written,
1248 * or re-read if the read failed.
1249 * We don't do much here, just schedule handling by raid1d
1250 */
1251 if (test_bit(BIO_UPTODATE, &bio->bi_flags))
1252 set_bit(R1BIO_Uptodate, &r1_bio->state);
1253
1254 if (atomic_dec_and_test(&r1_bio->remaining))
1255 reschedule_retry(r1_bio);
1256 }
1257
1258 static void end_sync_write(struct bio *bio, int error)
1259 {
1260 int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
1261 r1bio_t *r1_bio = bio->bi_private;
1262 mddev_t *mddev = r1_bio->mddev;
1263 conf_t *conf = mddev->private;
1264 int i;
1265 int mirror=0;
1266
1267 for (i = 0; i < conf->raid_disks; i++)
1268 if (r1_bio->bios[i] == bio) {
1269 mirror = i;
1270 break;
1271 }
1272 if (!uptodate) {
1273 sector_t sync_blocks = 0;
1274 sector_t s = r1_bio->sector;
1275 long sectors_to_go = r1_bio->sectors;
1276 /* make sure these bits doesn't get cleared. */
1277 do {
1278 bitmap_end_sync(mddev->bitmap, s,
1279 &sync_blocks, 1);
1280 s += sync_blocks;
1281 sectors_to_go -= sync_blocks;
1282 } while (sectors_to_go > 0);
1283 md_error(mddev, conf->mirrors[mirror].rdev);
1284 }
1285
1286 update_head_pos(mirror, r1_bio);
1287
1288 if (atomic_dec_and_test(&r1_bio->remaining)) {
1289 sector_t s = r1_bio->sectors;
1290 put_buf(r1_bio);
1291 md_done_sync(mddev, s, uptodate);
1292 }
1293 }
1294
1295 static int fix_sync_read_error(r1bio_t *r1_bio)
1296 {
1297 /* Try some synchronous reads of other devices to get
1298 * good data, much like with normal read errors. Only
1299 * read into the pages we already have so we don't
1300 * need to re-issue the read request.
1301 * We don't need to freeze the array, because being in an
1302 * active sync request, there is no normal IO, and
1303 * no overlapping syncs.
1304 * We don't need to check is_badblock() again as we
1305 * made sure that anything with a bad block in range
1306 * will have bi_end_io clear.
1307 */
1308 mddev_t *mddev = r1_bio->mddev;
1309 conf_t *conf = mddev->private;
1310 struct bio *bio = r1_bio->bios[r1_bio->read_disk];
1311 sector_t sect = r1_bio->sector;
1312 int sectors = r1_bio->sectors;
1313 int idx = 0;
1314
1315 while(sectors) {
1316 int s = sectors;
1317 int d = r1_bio->read_disk;
1318 int success = 0;
1319 mdk_rdev_t *rdev;
1320 int start;
1321
1322 if (s > (PAGE_SIZE>>9))
1323 s = PAGE_SIZE >> 9;
1324 do {
1325 if (r1_bio->bios[d]->bi_end_io == end_sync_read) {
1326 /* No rcu protection needed here devices
1327 * can only be removed when no resync is
1328 * active, and resync is currently active
1329 */
1330 rdev = conf->mirrors[d].rdev;
1331 if (sync_page_io(rdev, sect, s<<9,
1332 bio->bi_io_vec[idx].bv_page,
1333 READ, false)) {
1334 success = 1;
1335 break;
1336 }
1337 }
1338 d++;
1339 if (d == conf->raid_disks)
1340 d = 0;
1341 } while (!success && d != r1_bio->read_disk);
1342
1343 if (!success) {
1344 char b[BDEVNAME_SIZE];
1345 /* Cannot read from anywhere, array is toast */
1346 md_error(mddev, conf->mirrors[r1_bio->read_disk].rdev);
1347 printk(KERN_ALERT "md/raid1:%s: %s: unrecoverable I/O read error"
1348 " for block %llu\n",
1349 mdname(mddev),
1350 bdevname(bio->bi_bdev, b),
1351 (unsigned long long)r1_bio->sector);
1352 md_done_sync(mddev, r1_bio->sectors, 0);
1353 put_buf(r1_bio);
1354 return 0;
1355 }
1356
1357 start = d;
1358 /* write it back and re-read */
1359 while (d != r1_bio->read_disk) {
1360 if (d == 0)
1361 d = conf->raid_disks;
1362 d--;
1363 if (r1_bio->bios[d]->bi_end_io != end_sync_read)
1364 continue;
1365 rdev = conf->mirrors[d].rdev;
1366 if (sync_page_io(rdev, sect, s<<9,
1367 bio->bi_io_vec[idx].bv_page,
1368 WRITE, false) == 0) {
1369 r1_bio->bios[d]->bi_end_io = NULL;
1370 rdev_dec_pending(rdev, mddev);
1371 md_error(mddev, rdev);
1372 }
1373 }
1374 d = start;
1375 while (d != r1_bio->read_disk) {
1376 if (d == 0)
1377 d = conf->raid_disks;
1378 d--;
1379 if (r1_bio->bios[d]->bi_end_io != end_sync_read)
1380 continue;
1381 rdev = conf->mirrors[d].rdev;
1382 if (sync_page_io(rdev, sect, s<<9,
1383 bio->bi_io_vec[idx].bv_page,
1384 READ, false) == 0)
1385 md_error(mddev, rdev);
1386 else
1387 atomic_add(s, &rdev->corrected_errors);
1388 }
1389 sectors -= s;
1390 sect += s;
1391 idx ++;
1392 }
1393 set_bit(R1BIO_Uptodate, &r1_bio->state);
1394 set_bit(BIO_UPTODATE, &bio->bi_flags);
1395 return 1;
1396 }
1397
1398 static int process_checks(r1bio_t *r1_bio)
1399 {
1400 /* We have read all readable devices. If we haven't
1401 * got the block, then there is no hope left.
1402 * If we have, then we want to do a comparison
1403 * and skip the write if everything is the same.
1404 * If any blocks failed to read, then we need to
1405 * attempt an over-write
1406 */
1407 mddev_t *mddev = r1_bio->mddev;
1408 conf_t *conf = mddev->private;
1409 int primary;
1410 int i;
1411
1412 for (primary = 0; primary < conf->raid_disks; primary++)
1413 if (r1_bio->bios[primary]->bi_end_io == end_sync_read &&
1414 test_bit(BIO_UPTODATE, &r1_bio->bios[primary]->bi_flags)) {
1415 r1_bio->bios[primary]->bi_end_io = NULL;
1416 rdev_dec_pending(conf->mirrors[primary].rdev, mddev);
1417 break;
1418 }
1419 r1_bio->read_disk = primary;
1420 for (i = 0; i < conf->raid_disks; i++) {
1421 int j;
1422 int vcnt = r1_bio->sectors >> (PAGE_SHIFT- 9);
1423 struct bio *pbio = r1_bio->bios[primary];
1424 struct bio *sbio = r1_bio->bios[i];
1425 int size;
1426
1427 if (r1_bio->bios[i]->bi_end_io != end_sync_read)
1428 continue;
1429
1430 if (test_bit(BIO_UPTODATE, &sbio->bi_flags)) {
1431 for (j = vcnt; j-- ; ) {
1432 struct page *p, *s;
1433 p = pbio->bi_io_vec[j].bv_page;
1434 s = sbio->bi_io_vec[j].bv_page;
1435 if (memcmp(page_address(p),
1436 page_address(s),
1437 PAGE_SIZE))
1438 break;
1439 }
1440 } else
1441 j = 0;
1442 if (j >= 0)
1443 mddev->resync_mismatches += r1_bio->sectors;
1444 if (j < 0 || (test_bit(MD_RECOVERY_CHECK, &mddev->recovery)
1445 && test_bit(BIO_UPTODATE, &sbio->bi_flags))) {
1446 /* No need to write to this device. */
1447 sbio->bi_end_io = NULL;
1448 rdev_dec_pending(conf->mirrors[i].rdev, mddev);
1449 continue;
1450 }
1451 /* fixup the bio for reuse */
1452 sbio->bi_vcnt = vcnt;
1453 sbio->bi_size = r1_bio->sectors << 9;
1454 sbio->bi_idx = 0;
1455 sbio->bi_phys_segments = 0;
1456 sbio->bi_flags &= ~(BIO_POOL_MASK - 1);
1457 sbio->bi_flags |= 1 << BIO_UPTODATE;
1458 sbio->bi_next = NULL;
1459 sbio->bi_sector = r1_bio->sector +
1460 conf->mirrors[i].rdev->data_offset;
1461 sbio->bi_bdev = conf->mirrors[i].rdev->bdev;
1462 size = sbio->bi_size;
1463 for (j = 0; j < vcnt ; j++) {
1464 struct bio_vec *bi;
1465 bi = &sbio->bi_io_vec[j];
1466 bi->bv_offset = 0;
1467 if (size > PAGE_SIZE)
1468 bi->bv_len = PAGE_SIZE;
1469 else
1470 bi->bv_len = size;
1471 size -= PAGE_SIZE;
1472 memcpy(page_address(bi->bv_page),
1473 page_address(pbio->bi_io_vec[j].bv_page),
1474 PAGE_SIZE);
1475 }
1476 }
1477 return 0;
1478 }
1479
1480 static void sync_request_write(mddev_t *mddev, r1bio_t *r1_bio)
1481 {
1482 conf_t *conf = mddev->private;
1483 int i;
1484 int disks = conf->raid_disks;
1485 struct bio *bio, *wbio;
1486
1487 bio = r1_bio->bios[r1_bio->read_disk];
1488
1489 if (!test_bit(R1BIO_Uptodate, &r1_bio->state))
1490 /* ouch - failed to read all of that. */
1491 if (!fix_sync_read_error(r1_bio))
1492 return;
1493
1494 if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
1495 if (process_checks(r1_bio) < 0)
1496 return;
1497 /*
1498 * schedule writes
1499 */
1500 atomic_set(&r1_bio->remaining, 1);
1501 for (i = 0; i < disks ; i++) {
1502 wbio = r1_bio->bios[i];
1503 if (wbio->bi_end_io == NULL ||
1504 (wbio->bi_end_io == end_sync_read &&
1505 (i == r1_bio->read_disk ||
1506 !test_bit(MD_RECOVERY_SYNC, &mddev->recovery))))
1507 continue;
1508
1509 wbio->bi_rw = WRITE;
1510 wbio->bi_end_io = end_sync_write;
1511 atomic_inc(&r1_bio->remaining);
1512 md_sync_acct(conf->mirrors[i].rdev->bdev, wbio->bi_size >> 9);
1513
1514 generic_make_request(wbio);
1515 }
1516
1517 if (atomic_dec_and_test(&r1_bio->remaining)) {
1518 /* if we're here, all write(s) have completed, so clean up */
1519 md_done_sync(mddev, r1_bio->sectors, 1);
1520 put_buf(r1_bio);
1521 }
1522 }
1523
1524 /*
1525 * This is a kernel thread which:
1526 *
1527 * 1. Retries failed read operations on working mirrors.
1528 * 2. Updates the raid superblock when problems encounter.
1529 * 3. Performs writes following reads for array synchronising.
1530 */
1531
1532 static void fix_read_error(conf_t *conf, int read_disk,
1533 sector_t sect, int sectors)
1534 {
1535 mddev_t *mddev = conf->mddev;
1536 while(sectors) {
1537 int s = sectors;
1538 int d = read_disk;
1539 int success = 0;
1540 int start;
1541 mdk_rdev_t *rdev;
1542
1543 if (s > (PAGE_SIZE>>9))
1544 s = PAGE_SIZE >> 9;
1545
1546 do {
1547 /* Note: no rcu protection needed here
1548 * as this is synchronous in the raid1d thread
1549 * which is the thread that might remove
1550 * a device. If raid1d ever becomes multi-threaded....
1551 */
1552 sector_t first_bad;
1553 int bad_sectors;
1554
1555 rdev = conf->mirrors[d].rdev;
1556 if (rdev &&
1557 test_bit(In_sync, &rdev->flags) &&
1558 is_badblock(rdev, sect, s,
1559 &first_bad, &bad_sectors) == 0 &&
1560 sync_page_io(rdev, sect, s<<9,
1561 conf->tmppage, READ, false))
1562 success = 1;
1563 else {
1564 d++;
1565 if (d == conf->raid_disks)
1566 d = 0;
1567 }
1568 } while (!success && d != read_disk);
1569
1570 if (!success) {
1571 /* Cannot read from anywhere -- bye bye array */
1572 md_error(mddev, conf->mirrors[read_disk].rdev);
1573 break;
1574 }
1575 /* write it back and re-read */
1576 start = d;
1577 while (d != read_disk) {
1578 if (d==0)
1579 d = conf->raid_disks;
1580 d--;
1581 rdev = conf->mirrors[d].rdev;
1582 if (rdev &&
1583 test_bit(In_sync, &rdev->flags)) {
1584 if (sync_page_io(rdev, sect, s<<9,
1585 conf->tmppage, WRITE, false)
1586 == 0)
1587 /* Well, this device is dead */
1588 md_error(mddev, rdev);
1589 }
1590 }
1591 d = start;
1592 while (d != read_disk) {
1593 char b[BDEVNAME_SIZE];
1594 if (d==0)
1595 d = conf->raid_disks;
1596 d--;
1597 rdev = conf->mirrors[d].rdev;
1598 if (rdev &&
1599 test_bit(In_sync, &rdev->flags)) {
1600 if (sync_page_io(rdev, sect, s<<9,
1601 conf->tmppage, READ, false)
1602 == 0)
1603 /* Well, this device is dead */
1604 md_error(mddev, rdev);
1605 else {
1606 atomic_add(s, &rdev->corrected_errors);
1607 printk(KERN_INFO
1608 "md/raid1:%s: read error corrected "
1609 "(%d sectors at %llu on %s)\n",
1610 mdname(mddev), s,
1611 (unsigned long long)(sect +
1612 rdev->data_offset),
1613 bdevname(rdev->bdev, b));
1614 }
1615 }
1616 }
1617 sectors -= s;
1618 sect += s;
1619 }
1620 }
1621
1622 static void raid1d(mddev_t *mddev)
1623 {
1624 r1bio_t *r1_bio;
1625 struct bio *bio;
1626 unsigned long flags;
1627 conf_t *conf = mddev->private;
1628 struct list_head *head = &conf->retry_list;
1629 mdk_rdev_t *rdev;
1630 struct blk_plug plug;
1631
1632 md_check_recovery(mddev);
1633
1634 blk_start_plug(&plug);
1635 for (;;) {
1636 char b[BDEVNAME_SIZE];
1637
1638 if (atomic_read(&mddev->plug_cnt) == 0)
1639 flush_pending_writes(conf);
1640
1641 spin_lock_irqsave(&conf->device_lock, flags);
1642 if (list_empty(head)) {
1643 spin_unlock_irqrestore(&conf->device_lock, flags);
1644 break;
1645 }
1646 r1_bio = list_entry(head->prev, r1bio_t, retry_list);
1647 list_del(head->prev);
1648 conf->nr_queued--;
1649 spin_unlock_irqrestore(&conf->device_lock, flags);
1650
1651 mddev = r1_bio->mddev;
1652 conf = mddev->private;
1653 if (test_bit(R1BIO_IsSync, &r1_bio->state))
1654 sync_request_write(mddev, r1_bio);
1655 else if (test_bit(R1BIO_ReadError, &r1_bio->state)) {
1656 int disk;
1657 int max_sectors;
1658
1659 clear_bit(R1BIO_ReadError, &r1_bio->state);
1660 /* we got a read error. Maybe the drive is bad. Maybe just
1661 * the block and we can fix it.
1662 * We freeze all other IO, and try reading the block from
1663 * other devices. When we find one, we re-write
1664 * and check it that fixes the read error.
1665 * This is all done synchronously while the array is
1666 * frozen
1667 */
1668 if (mddev->ro == 0) {
1669 freeze_array(conf);
1670 fix_read_error(conf, r1_bio->read_disk,
1671 r1_bio->sector,
1672 r1_bio->sectors);
1673 unfreeze_array(conf);
1674 } else
1675 md_error(mddev,
1676 conf->mirrors[r1_bio->read_disk].rdev);
1677
1678 bio = r1_bio->bios[r1_bio->read_disk];
1679 bdevname(bio->bi_bdev, b);
1680 read_more:
1681 disk = read_balance(conf, r1_bio, &max_sectors);
1682 if (disk == -1) {
1683 printk(KERN_ALERT "md/raid1:%s: %s: unrecoverable I/O"
1684 " read error for block %llu\n",
1685 mdname(mddev), b,
1686 (unsigned long long)r1_bio->sector);
1687 raid_end_bio_io(r1_bio);
1688 } else {
1689 const unsigned long do_sync = r1_bio->master_bio->bi_rw & REQ_SYNC;
1690 if (bio) {
1691 r1_bio->bios[r1_bio->read_disk] =
1692 mddev->ro ? IO_BLOCKED : NULL;
1693 bio_put(bio);
1694 }
1695 r1_bio->read_disk = disk;
1696 bio = bio_clone_mddev(r1_bio->master_bio,
1697 GFP_NOIO, mddev);
1698 md_trim_bio(bio,
1699 r1_bio->sector - bio->bi_sector,
1700 max_sectors);
1701 r1_bio->bios[r1_bio->read_disk] = bio;
1702 rdev = conf->mirrors[disk].rdev;
1703 printk_ratelimited(
1704 KERN_ERR
1705 "md/raid1:%s: redirecting sector %llu"
1706 " to other mirror: %s\n",
1707 mdname(mddev),
1708 (unsigned long long)r1_bio->sector,
1709 bdevname(rdev->bdev, b));
1710 bio->bi_sector = r1_bio->sector + rdev->data_offset;
1711 bio->bi_bdev = rdev->bdev;
1712 bio->bi_end_io = raid1_end_read_request;
1713 bio->bi_rw = READ | do_sync;
1714 bio->bi_private = r1_bio;
1715 if (max_sectors < r1_bio->sectors) {
1716 /* Drat - have to split this up more */
1717 struct bio *mbio = r1_bio->master_bio;
1718 int sectors_handled =
1719 r1_bio->sector + max_sectors
1720 - mbio->bi_sector;
1721 r1_bio->sectors = max_sectors;
1722 spin_lock_irq(&conf->device_lock);
1723 if (mbio->bi_phys_segments == 0)
1724 mbio->bi_phys_segments = 2;
1725 else
1726 mbio->bi_phys_segments++;
1727 spin_unlock_irq(&conf->device_lock);
1728 generic_make_request(bio);
1729 bio = NULL;
1730
1731 r1_bio = mempool_alloc(conf->r1bio_pool,
1732 GFP_NOIO);
1733
1734 r1_bio->master_bio = mbio;
1735 r1_bio->sectors = (mbio->bi_size >> 9)
1736 - sectors_handled;
1737 r1_bio->state = 0;
1738 set_bit(R1BIO_ReadError,
1739 &r1_bio->state);
1740 r1_bio->mddev = mddev;
1741 r1_bio->sector = mbio->bi_sector
1742 + sectors_handled;
1743
1744 goto read_more;
1745 } else
1746 generic_make_request(bio);
1747 }
1748 } else {
1749 /* just a partial read to be scheduled from separate
1750 * context
1751 */
1752 generic_make_request(r1_bio->bios[r1_bio->read_disk]);
1753 }
1754 cond_resched();
1755 if (mddev->flags & ~(1<<MD_CHANGE_PENDING))
1756 md_check_recovery(mddev);
1757 }
1758 blk_finish_plug(&plug);
1759 }
1760
1761
1762 static int init_resync(conf_t *conf)
1763 {
1764 int buffs;
1765
1766 buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE;
1767 BUG_ON(conf->r1buf_pool);
1768 conf->r1buf_pool = mempool_create(buffs, r1buf_pool_alloc, r1buf_pool_free,
1769 conf->poolinfo);
1770 if (!conf->r1buf_pool)
1771 return -ENOMEM;
1772 conf->next_resync = 0;
1773 return 0;
1774 }
1775
1776 /*
1777 * perform a "sync" on one "block"
1778 *
1779 * We need to make sure that no normal I/O request - particularly write
1780 * requests - conflict with active sync requests.
1781 *
1782 * This is achieved by tracking pending requests and a 'barrier' concept
1783 * that can be installed to exclude normal IO requests.
1784 */
1785
1786 static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster)
1787 {
1788 conf_t *conf = mddev->private;
1789 r1bio_t *r1_bio;
1790 struct bio *bio;
1791 sector_t max_sector, nr_sectors;
1792 int disk = -1;
1793 int i;
1794 int wonly = -1;
1795 int write_targets = 0, read_targets = 0;
1796 sector_t sync_blocks;
1797 int still_degraded = 0;
1798 int good_sectors = RESYNC_SECTORS;
1799 int min_bad = 0; /* number of sectors that are bad in all devices */
1800
1801 if (!conf->r1buf_pool)
1802 if (init_resync(conf))
1803 return 0;
1804
1805 max_sector = mddev->dev_sectors;
1806 if (sector_nr >= max_sector) {
1807 /* If we aborted, we need to abort the
1808 * sync on the 'current' bitmap chunk (there will
1809 * only be one in raid1 resync.
1810 * We can find the current addess in mddev->curr_resync
1811 */
1812 if (mddev->curr_resync < max_sector) /* aborted */
1813 bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
1814 &sync_blocks, 1);
1815 else /* completed sync */
1816 conf->fullsync = 0;
1817
1818 bitmap_close_sync(mddev->bitmap);
1819 close_sync(conf);
1820 return 0;
1821 }
1822
1823 if (mddev->bitmap == NULL &&
1824 mddev->recovery_cp == MaxSector &&
1825 !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
1826 conf->fullsync == 0) {
1827 *skipped = 1;
1828 return max_sector - sector_nr;
1829 }
1830 /* before building a request, check if we can skip these blocks..
1831 * This call the bitmap_start_sync doesn't actually record anything
1832 */
1833 if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
1834 !conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
1835 /* We can skip this block, and probably several more */
1836 *skipped = 1;
1837 return sync_blocks;
1838 }
1839 /*
1840 * If there is non-resync activity waiting for a turn,
1841 * and resync is going fast enough,
1842 * then let it though before starting on this new sync request.
1843 */
1844 if (!go_faster && conf->nr_waiting)
1845 msleep_interruptible(1000);
1846
1847 bitmap_cond_end_sync(mddev->bitmap, sector_nr);
1848 r1_bio = mempool_alloc(conf->r1buf_pool, GFP_NOIO);
1849 raise_barrier(conf);
1850
1851 conf->next_resync = sector_nr;
1852
1853 rcu_read_lock();
1854 /*
1855 * If we get a correctably read error during resync or recovery,
1856 * we might want to read from a different device. So we
1857 * flag all drives that could conceivably be read from for READ,
1858 * and any others (which will be non-In_sync devices) for WRITE.
1859 * If a read fails, we try reading from something else for which READ
1860 * is OK.
1861 */
1862
1863 r1_bio->mddev = mddev;
1864 r1_bio->sector = sector_nr;
1865 r1_bio->state = 0;
1866 set_bit(R1BIO_IsSync, &r1_bio->state);
1867
1868 for (i=0; i < conf->raid_disks; i++) {
1869 mdk_rdev_t *rdev;
1870 bio = r1_bio->bios[i];
1871
1872 /* take from bio_init */
1873 bio->bi_next = NULL;
1874 bio->bi_flags &= ~(BIO_POOL_MASK-1);
1875 bio->bi_flags |= 1 << BIO_UPTODATE;
1876 bio->bi_comp_cpu = -1;
1877 bio->bi_rw = READ;
1878 bio->bi_vcnt = 0;
1879 bio->bi_idx = 0;
1880 bio->bi_phys_segments = 0;
1881 bio->bi_size = 0;
1882 bio->bi_end_io = NULL;
1883 bio->bi_private = NULL;
1884
1885 rdev = rcu_dereference(conf->mirrors[i].rdev);
1886 if (rdev == NULL ||
1887 test_bit(Faulty, &rdev->flags)) {
1888 still_degraded = 1;
1889 } else if (!test_bit(In_sync, &rdev->flags)) {
1890 bio->bi_rw = WRITE;
1891 bio->bi_end_io = end_sync_write;
1892 write_targets ++;
1893 } else {
1894 /* may need to read from here */
1895 sector_t first_bad = MaxSector;
1896 int bad_sectors;
1897
1898 if (is_badblock(rdev, sector_nr, good_sectors,
1899 &first_bad, &bad_sectors)) {
1900 if (first_bad > sector_nr)
1901 good_sectors = first_bad - sector_nr;
1902 else {
1903 bad_sectors -= (sector_nr - first_bad);
1904 if (min_bad == 0 ||
1905 min_bad > bad_sectors)
1906 min_bad = bad_sectors;
1907 }
1908 }
1909 if (sector_nr < first_bad) {
1910 if (test_bit(WriteMostly, &rdev->flags)) {
1911 if (wonly < 0)
1912 wonly = i;
1913 } else {
1914 if (disk < 0)
1915 disk = i;
1916 }
1917 bio->bi_rw = READ;
1918 bio->bi_end_io = end_sync_read;
1919 read_targets++;
1920 }
1921 }
1922 if (bio->bi_end_io) {
1923 atomic_inc(&rdev->nr_pending);
1924 bio->bi_sector = sector_nr + rdev->data_offset;
1925 bio->bi_bdev = rdev->bdev;
1926 bio->bi_private = r1_bio;
1927 }
1928 }
1929 rcu_read_unlock();
1930 if (disk < 0)
1931 disk = wonly;
1932 r1_bio->read_disk = disk;
1933
1934 if (read_targets == 0 && min_bad > 0) {
1935 /* These sectors are bad on all InSync devices, so we
1936 * need to mark them bad on all write targets
1937 */
1938 int ok = 1;
1939 for (i = 0 ; i < conf->raid_disks ; i++)
1940 if (r1_bio->bios[i]->bi_end_io == end_sync_write) {
1941 mdk_rdev_t *rdev =
1942 rcu_dereference(conf->mirrors[i].rdev);
1943 ok = rdev_set_badblocks(rdev, sector_nr,
1944 min_bad, 0
1945 ) && ok;
1946 }
1947 set_bit(MD_CHANGE_DEVS, &mddev->flags);
1948 *skipped = 1;
1949 put_buf(r1_bio);
1950
1951 if (!ok) {
1952 /* Cannot record the badblocks, so need to
1953 * abort the resync.
1954 * If there are multiple read targets, could just
1955 * fail the really bad ones ???
1956 */
1957 conf->recovery_disabled = mddev->recovery_disabled;
1958 set_bit(MD_RECOVERY_INTR, &mddev->recovery);
1959 return 0;
1960 } else
1961 return min_bad;
1962
1963 }
1964 if (min_bad > 0 && min_bad < good_sectors) {
1965 /* only resync enough to reach the next bad->good
1966 * transition */
1967 good_sectors = min_bad;
1968 }
1969
1970 if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) && read_targets > 0)
1971 /* extra read targets are also write targets */
1972 write_targets += read_targets-1;
1973
1974 if (write_targets == 0 || read_targets == 0) {
1975 /* There is nowhere to write, so all non-sync
1976 * drives must be failed - so we are finished
1977 */
1978 sector_t rv = max_sector - sector_nr;
1979 *skipped = 1;
1980 put_buf(r1_bio);
1981 return rv;
1982 }
1983
1984 if (max_sector > mddev->resync_max)
1985 max_sector = mddev->resync_max; /* Don't do IO beyond here */
1986 if (max_sector > sector_nr + good_sectors)
1987 max_sector = sector_nr + good_sectors;
1988 nr_sectors = 0;
1989 sync_blocks = 0;
1990 do {
1991 struct page *page;
1992 int len = PAGE_SIZE;
1993 if (sector_nr + (len>>9) > max_sector)
1994 len = (max_sector - sector_nr) << 9;
1995 if (len == 0)
1996 break;
1997 if (sync_blocks == 0) {
1998 if (!bitmap_start_sync(mddev->bitmap, sector_nr,
1999 &sync_blocks, still_degraded) &&
2000 !conf->fullsync &&
2001 !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
2002 break;
2003 BUG_ON(sync_blocks < (PAGE_SIZE>>9));
2004 if ((len >> 9) > sync_blocks)
2005 len = sync_blocks<<9;
2006 }
2007
2008 for (i=0 ; i < conf->raid_disks; i++) {
2009 bio = r1_bio->bios[i];
2010 if (bio->bi_end_io) {
2011 page = bio->bi_io_vec[bio->bi_vcnt].bv_page;
2012 if (bio_add_page(bio, page, len, 0) == 0) {
2013 /* stop here */
2014 bio->bi_io_vec[bio->bi_vcnt].bv_page = page;
2015 while (i > 0) {
2016 i--;
2017 bio = r1_bio->bios[i];
2018 if (bio->bi_end_io==NULL)
2019 continue;
2020 /* remove last page from this bio */
2021 bio->bi_vcnt--;
2022 bio->bi_size -= len;
2023 bio->bi_flags &= ~(1<< BIO_SEG_VALID);
2024 }
2025 goto bio_full;
2026 }
2027 }
2028 }
2029 nr_sectors += len>>9;
2030 sector_nr += len>>9;
2031 sync_blocks -= (len>>9);
2032 } while (r1_bio->bios[disk]->bi_vcnt < RESYNC_PAGES);
2033 bio_full:
2034 r1_bio->sectors = nr_sectors;
2035
2036 /* For a user-requested sync, we read all readable devices and do a
2037 * compare
2038 */
2039 if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
2040 atomic_set(&r1_bio->remaining, read_targets);
2041 for (i=0; i<conf->raid_disks; i++) {
2042 bio = r1_bio->bios[i];
2043 if (bio->bi_end_io == end_sync_read) {
2044 md_sync_acct(bio->bi_bdev, nr_sectors);
2045 generic_make_request(bio);
2046 }
2047 }
2048 } else {
2049 atomic_set(&r1_bio->remaining, 1);
2050 bio = r1_bio->bios[r1_bio->read_disk];
2051 md_sync_acct(bio->bi_bdev, nr_sectors);
2052 generic_make_request(bio);
2053
2054 }
2055 return nr_sectors;
2056 }
2057
2058 static sector_t raid1_size(mddev_t *mddev, sector_t sectors, int raid_disks)
2059 {
2060 if (sectors)
2061 return sectors;
2062
2063 return mddev->dev_sectors;
2064 }
2065
2066 static conf_t *setup_conf(mddev_t *mddev)
2067 {
2068 conf_t *conf;
2069 int i;
2070 mirror_info_t *disk;
2071 mdk_rdev_t *rdev;
2072 int err = -ENOMEM;
2073
2074 conf = kzalloc(sizeof(conf_t), GFP_KERNEL);
2075 if (!conf)
2076 goto abort;
2077
2078 conf->mirrors = kzalloc(sizeof(struct mirror_info)*mddev->raid_disks,
2079 GFP_KERNEL);
2080 if (!conf->mirrors)
2081 goto abort;
2082
2083 conf->tmppage = alloc_page(GFP_KERNEL);
2084 if (!conf->tmppage)
2085 goto abort;
2086
2087 conf->poolinfo = kzalloc(sizeof(*conf->poolinfo), GFP_KERNEL);
2088 if (!conf->poolinfo)
2089 goto abort;
2090 conf->poolinfo->raid_disks = mddev->raid_disks;
2091 conf->r1bio_pool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc,
2092 r1bio_pool_free,
2093 conf->poolinfo);
2094 if (!conf->r1bio_pool)
2095 goto abort;
2096
2097 conf->poolinfo->mddev = mddev;
2098
2099 spin_lock_init(&conf->device_lock);
2100 list_for_each_entry(rdev, &mddev->disks, same_set) {
2101 int disk_idx = rdev->raid_disk;
2102 if (disk_idx >= mddev->raid_disks
2103 || disk_idx < 0)
2104 continue;
2105 disk = conf->mirrors + disk_idx;
2106
2107 disk->rdev = rdev;
2108
2109 disk->head_position = 0;
2110 }
2111 conf->raid_disks = mddev->raid_disks;
2112 conf->mddev = mddev;
2113 INIT_LIST_HEAD(&conf->retry_list);
2114
2115 spin_lock_init(&conf->resync_lock);
2116 init_waitqueue_head(&conf->wait_barrier);
2117
2118 bio_list_init(&conf->pending_bio_list);
2119
2120 conf->last_used = -1;
2121 for (i = 0; i < conf->raid_disks; i++) {
2122
2123 disk = conf->mirrors + i;
2124
2125 if (!disk->rdev ||
2126 !test_bit(In_sync, &disk->rdev->flags)) {
2127 disk->head_position = 0;
2128 if (disk->rdev)
2129 conf->fullsync = 1;
2130 } else if (conf->last_used < 0)
2131 /*
2132 * The first working device is used as a
2133 * starting point to read balancing.
2134 */
2135 conf->last_used = i;
2136 }
2137
2138 err = -EIO;
2139 if (conf->last_used < 0) {
2140 printk(KERN_ERR "md/raid1:%s: no operational mirrors\n",
2141 mdname(mddev));
2142 goto abort;
2143 }
2144 err = -ENOMEM;
2145 conf->thread = md_register_thread(raid1d, mddev, NULL);
2146 if (!conf->thread) {
2147 printk(KERN_ERR
2148 "md/raid1:%s: couldn't allocate thread\n",
2149 mdname(mddev));
2150 goto abort;
2151 }
2152
2153 return conf;
2154
2155 abort:
2156 if (conf) {
2157 if (conf->r1bio_pool)
2158 mempool_destroy(conf->r1bio_pool);
2159 kfree(conf->mirrors);
2160 safe_put_page(conf->tmppage);
2161 kfree(conf->poolinfo);
2162 kfree(conf);
2163 }
2164 return ERR_PTR(err);
2165 }
2166
2167 static int run(mddev_t *mddev)
2168 {
2169 conf_t *conf;
2170 int i;
2171 mdk_rdev_t *rdev;
2172
2173 if (mddev->level != 1) {
2174 printk(KERN_ERR "md/raid1:%s: raid level not set to mirroring (%d)\n",
2175 mdname(mddev), mddev->level);
2176 return -EIO;
2177 }
2178 if (mddev->reshape_position != MaxSector) {
2179 printk(KERN_ERR "md/raid1:%s: reshape_position set but not supported\n",
2180 mdname(mddev));
2181 return -EIO;
2182 }
2183 /*
2184 * copy the already verified devices into our private RAID1
2185 * bookkeeping area. [whatever we allocate in run(),
2186 * should be freed in stop()]
2187 */
2188 if (mddev->private == NULL)
2189 conf = setup_conf(mddev);
2190 else
2191 conf = mddev->private;
2192
2193 if (IS_ERR(conf))
2194 return PTR_ERR(conf);
2195
2196 list_for_each_entry(rdev, &mddev->disks, same_set) {
2197 if (!mddev->gendisk)
2198 continue;
2199 disk_stack_limits(mddev->gendisk, rdev->bdev,
2200 rdev->data_offset << 9);
2201 /* as we don't honour merge_bvec_fn, we must never risk
2202 * violating it, so limit ->max_segments to 1 lying within
2203 * a single page, as a one page request is never in violation.
2204 */
2205 if (rdev->bdev->bd_disk->queue->merge_bvec_fn) {
2206 blk_queue_max_segments(mddev->queue, 1);
2207 blk_queue_segment_boundary(mddev->queue,
2208 PAGE_CACHE_SIZE - 1);
2209 }
2210 }
2211
2212 mddev->degraded = 0;
2213 for (i=0; i < conf->raid_disks; i++)
2214 if (conf->mirrors[i].rdev == NULL ||
2215 !test_bit(In_sync, &conf->mirrors[i].rdev->flags) ||
2216 test_bit(Faulty, &conf->mirrors[i].rdev->flags))
2217 mddev->degraded++;
2218
2219 if (conf->raid_disks - mddev->degraded == 1)
2220 mddev->recovery_cp = MaxSector;
2221
2222 if (mddev->recovery_cp != MaxSector)
2223 printk(KERN_NOTICE "md/raid1:%s: not clean"
2224 " -- starting background reconstruction\n",
2225 mdname(mddev));
2226 printk(KERN_INFO
2227 "md/raid1:%s: active with %d out of %d mirrors\n",
2228 mdname(mddev), mddev->raid_disks - mddev->degraded,
2229 mddev->raid_disks);
2230
2231 /*
2232 * Ok, everything is just fine now
2233 */
2234 mddev->thread = conf->thread;
2235 conf->thread = NULL;
2236 mddev->private = conf;
2237
2238 md_set_array_sectors(mddev, raid1_size(mddev, 0, 0));
2239
2240 if (mddev->queue) {
2241 mddev->queue->backing_dev_info.congested_fn = raid1_congested;
2242 mddev->queue->backing_dev_info.congested_data = mddev;
2243 }
2244 return md_integrity_register(mddev);
2245 }
2246
2247 static int stop(mddev_t *mddev)
2248 {
2249 conf_t *conf = mddev->private;
2250 struct bitmap *bitmap = mddev->bitmap;
2251
2252 /* wait for behind writes to complete */
2253 if (bitmap && atomic_read(&bitmap->behind_writes) > 0) {
2254 printk(KERN_INFO "md/raid1:%s: behind writes in progress - waiting to stop.\n",
2255 mdname(mddev));
2256 /* need to kick something here to make sure I/O goes? */
2257 wait_event(bitmap->behind_wait,
2258 atomic_read(&bitmap->behind_writes) == 0);
2259 }
2260
2261 raise_barrier(conf);
2262 lower_barrier(conf);
2263
2264 md_unregister_thread(mddev->thread);
2265 mddev->thread = NULL;
2266 if (conf->r1bio_pool)
2267 mempool_destroy(conf->r1bio_pool);
2268 kfree(conf->mirrors);
2269 kfree(conf->poolinfo);
2270 kfree(conf);
2271 mddev->private = NULL;
2272 return 0;
2273 }
2274
2275 static int raid1_resize(mddev_t *mddev, sector_t sectors)
2276 {
2277 /* no resync is happening, and there is enough space
2278 * on all devices, so we can resize.
2279 * We need to make sure resync covers any new space.
2280 * If the array is shrinking we should possibly wait until
2281 * any io in the removed space completes, but it hardly seems
2282 * worth it.
2283 */
2284 md_set_array_sectors(mddev, raid1_size(mddev, sectors, 0));
2285 if (mddev->array_sectors > raid1_size(mddev, sectors, 0))
2286 return -EINVAL;
2287 set_capacity(mddev->gendisk, mddev->array_sectors);
2288 revalidate_disk(mddev->gendisk);
2289 if (sectors > mddev->dev_sectors &&
2290 mddev->recovery_cp > mddev->dev_sectors) {
2291 mddev->recovery_cp = mddev->dev_sectors;
2292 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
2293 }
2294 mddev->dev_sectors = sectors;
2295 mddev->resync_max_sectors = sectors;
2296 return 0;
2297 }
2298
2299 static int raid1_reshape(mddev_t *mddev)
2300 {
2301 /* We need to:
2302 * 1/ resize the r1bio_pool
2303 * 2/ resize conf->mirrors
2304 *
2305 * We allocate a new r1bio_pool if we can.
2306 * Then raise a device barrier and wait until all IO stops.
2307 * Then resize conf->mirrors and swap in the new r1bio pool.
2308 *
2309 * At the same time, we "pack" the devices so that all the missing
2310 * devices have the higher raid_disk numbers.
2311 */
2312 mempool_t *newpool, *oldpool;
2313 struct pool_info *newpoolinfo;
2314 mirror_info_t *newmirrors;
2315 conf_t *conf = mddev->private;
2316 int cnt, raid_disks;
2317 unsigned long flags;
2318 int d, d2, err;
2319
2320 /* Cannot change chunk_size, layout, or level */
2321 if (mddev->chunk_sectors != mddev->new_chunk_sectors ||
2322 mddev->layout != mddev->new_layout ||
2323 mddev->level != mddev->new_level) {
2324 mddev->new_chunk_sectors = mddev->chunk_sectors;
2325 mddev->new_layout = mddev->layout;
2326 mddev->new_level = mddev->level;
2327 return -EINVAL;
2328 }
2329
2330 err = md_allow_write(mddev);
2331 if (err)
2332 return err;
2333
2334 raid_disks = mddev->raid_disks + mddev->delta_disks;
2335
2336 if (raid_disks < conf->raid_disks) {
2337 cnt=0;
2338 for (d= 0; d < conf->raid_disks; d++)
2339 if (conf->mirrors[d].rdev)
2340 cnt++;
2341 if (cnt > raid_disks)
2342 return -EBUSY;
2343 }
2344
2345 newpoolinfo = kmalloc(sizeof(*newpoolinfo), GFP_KERNEL);
2346 if (!newpoolinfo)
2347 return -ENOMEM;
2348 newpoolinfo->mddev = mddev;
2349 newpoolinfo->raid_disks = raid_disks;
2350
2351 newpool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc,
2352 r1bio_pool_free, newpoolinfo);
2353 if (!newpool) {
2354 kfree(newpoolinfo);
2355 return -ENOMEM;
2356 }
2357 newmirrors = kzalloc(sizeof(struct mirror_info) * raid_disks, GFP_KERNEL);
2358 if (!newmirrors) {
2359 kfree(newpoolinfo);
2360 mempool_destroy(newpool);
2361 return -ENOMEM;
2362 }
2363
2364 raise_barrier(conf);
2365
2366 /* ok, everything is stopped */
2367 oldpool = conf->r1bio_pool;
2368 conf->r1bio_pool = newpool;
2369
2370 for (d = d2 = 0; d < conf->raid_disks; d++) {
2371 mdk_rdev_t *rdev = conf->mirrors[d].rdev;
2372 if (rdev && rdev->raid_disk != d2) {
2373 sysfs_unlink_rdev(mddev, rdev);
2374 rdev->raid_disk = d2;
2375 sysfs_unlink_rdev(mddev, rdev);
2376 if (sysfs_link_rdev(mddev, rdev))
2377 printk(KERN_WARNING
2378 "md/raid1:%s: cannot register rd%d\n",
2379 mdname(mddev), rdev->raid_disk);
2380 }
2381 if (rdev)
2382 newmirrors[d2++].rdev = rdev;
2383 }
2384 kfree(conf->mirrors);
2385 conf->mirrors = newmirrors;
2386 kfree(conf->poolinfo);
2387 conf->poolinfo = newpoolinfo;
2388
2389 spin_lock_irqsave(&conf->device_lock, flags);
2390 mddev->degraded += (raid_disks - conf->raid_disks);
2391 spin_unlock_irqrestore(&conf->device_lock, flags);
2392 conf->raid_disks = mddev->raid_disks = raid_disks;
2393 mddev->delta_disks = 0;
2394
2395 conf->last_used = 0; /* just make sure it is in-range */
2396 lower_barrier(conf);
2397
2398 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
2399 md_wakeup_thread(mddev->thread);
2400
2401 mempool_destroy(oldpool);
2402 return 0;
2403 }
2404
2405 static void raid1_quiesce(mddev_t *mddev, int state)
2406 {
2407 conf_t *conf = mddev->private;
2408
2409 switch(state) {
2410 case 2: /* wake for suspend */
2411 wake_up(&conf->wait_barrier);
2412 break;
2413 case 1:
2414 raise_barrier(conf);
2415 break;
2416 case 0:
2417 lower_barrier(conf);
2418 break;
2419 }
2420 }
2421
2422 static void *raid1_takeover(mddev_t *mddev)
2423 {
2424 /* raid1 can take over:
2425 * raid5 with 2 devices, any layout or chunk size
2426 */
2427 if (mddev->level == 5 && mddev->raid_disks == 2) {
2428 conf_t *conf;
2429 mddev->new_level = 1;
2430 mddev->new_layout = 0;
2431 mddev->new_chunk_sectors = 0;
2432 conf = setup_conf(mddev);
2433 if (!IS_ERR(conf))
2434 conf->barrier = 1;
2435 return conf;
2436 }
2437 return ERR_PTR(-EINVAL);
2438 }
2439
2440 static struct mdk_personality raid1_personality =
2441 {
2442 .name = "raid1",
2443 .level = 1,
2444 .owner = THIS_MODULE,
2445 .make_request = make_request,
2446 .run = run,
2447 .stop = stop,
2448 .status = status,
2449 .error_handler = error,
2450 .hot_add_disk = raid1_add_disk,
2451 .hot_remove_disk= raid1_remove_disk,
2452 .spare_active = raid1_spare_active,
2453 .sync_request = sync_request,
2454 .resize = raid1_resize,
2455 .size = raid1_size,
2456 .check_reshape = raid1_reshape,
2457 .quiesce = raid1_quiesce,
2458 .takeover = raid1_takeover,
2459 };
2460
2461 static int __init raid_init(void)
2462 {
2463 return register_md_personality(&raid1_personality);
2464 }
2465
2466 static void raid_exit(void)
2467 {
2468 unregister_md_personality(&raid1_personality);
2469 }
2470
2471 module_init(raid_init);
2472 module_exit(raid_exit);
2473 MODULE_LICENSE("GPL");
2474 MODULE_DESCRIPTION("RAID1 (mirroring) personality for MD");
2475 MODULE_ALIAS("md-personality-3"); /* RAID1 */
2476 MODULE_ALIAS("md-raid1");
2477 MODULE_ALIAS("md-level-1");
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