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kbuild: document howto build external modules using several directories
[linux-2.6/verdex.git] / drivers / md / raid1.c
blob229d7b20429721f0939fd84d207bff5441127d4b
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 "dm-bio-list.h"
35 #include <linux/raid/raid1.h>
36 #include <linux/raid/bitmap.h>
37
38 #define DEBUG 0
39 #if DEBUG
40 #define PRINTK(x...) printk(x)
41 #else
42 #define PRINTK(x...)
43 #endif
44
45 /*
46 * Number of guaranteed r1bios in case of extreme VM load:
47 */
48 #define NR_RAID1_BIOS 256
49
50 static mdk_personality_t raid1_personality;
51
52 static void unplug_slaves(mddev_t *mddev);
53
54
55 static void * r1bio_pool_alloc(gfp_t gfp_flags, void *data)
56 {
57 struct pool_info *pi = data;
58 r1bio_t *r1_bio;
59 int size = offsetof(r1bio_t, bios[pi->raid_disks]);
60
61 /* allocate a r1bio with room for raid_disks entries in the bios array */
62 r1_bio = kmalloc(size, gfp_flags);
63 if (r1_bio)
64 memset(r1_bio, 0, size);
65 else
66 unplug_slaves(pi->mddev);
67
68 return r1_bio;
69 }
70
71 static void r1bio_pool_free(void *r1_bio, void *data)
72 {
73 kfree(r1_bio);
74 }
75
76 #define RESYNC_BLOCK_SIZE (64*1024)
77 //#define RESYNC_BLOCK_SIZE PAGE_SIZE
78 #define RESYNC_SECTORS (RESYNC_BLOCK_SIZE >> 9)
79 #define RESYNC_PAGES ((RESYNC_BLOCK_SIZE + PAGE_SIZE-1) / PAGE_SIZE)
80 #define RESYNC_WINDOW (2048*1024)
81
82 static void * r1buf_pool_alloc(gfp_t gfp_flags, void *data)
83 {
84 struct pool_info *pi = data;
85 struct page *page;
86 r1bio_t *r1_bio;
87 struct bio *bio;
88 int i, j;
89
90 r1_bio = r1bio_pool_alloc(gfp_flags, pi);
91 if (!r1_bio) {
92 unplug_slaves(pi->mddev);
93 return NULL;
94 }
95
96 /*
97 * Allocate bios : 1 for reading, n-1 for writing
98 */
99 for (j = pi->raid_disks ; j-- ; ) {
100 bio = bio_alloc(gfp_flags, RESYNC_PAGES);
101 if (!bio)
102 goto out_free_bio;
103 r1_bio->bios[j] = bio;
104 }
105 /*
106 * Allocate RESYNC_PAGES data pages and attach them to
107 * the first bio;
108 */
109 bio = r1_bio->bios[0];
110 for (i = 0; i < RESYNC_PAGES; i++) {
111 page = alloc_page(gfp_flags);
112 if (unlikely(!page))
113 goto out_free_pages;
114
115 bio->bi_io_vec[i].bv_page = page;
116 }
117
118 r1_bio->master_bio = NULL;
119
120 return r1_bio;
121
122 out_free_pages:
123 for ( ; i > 0 ; i--)
124 __free_page(bio->bi_io_vec[i-1].bv_page);
125 out_free_bio:
126 while ( ++j < pi->raid_disks )
127 bio_put(r1_bio->bios[j]);
128 r1bio_pool_free(r1_bio, data);
129 return NULL;
130 }
131
132 static void r1buf_pool_free(void *__r1_bio, void *data)
133 {
134 struct pool_info *pi = data;
135 int i;
136 r1bio_t *r1bio = __r1_bio;
137 struct bio *bio = r1bio->bios[0];
138
139 for (i = 0; i < RESYNC_PAGES; i++) {
140 __free_page(bio->bi_io_vec[i].bv_page);
141 bio->bi_io_vec[i].bv_page = NULL;
142 }
143 for (i=0 ; i < pi->raid_disks; i++)
144 bio_put(r1bio->bios[i]);
145
146 r1bio_pool_free(r1bio, data);
147 }
148
149 static void put_all_bios(conf_t *conf, r1bio_t *r1_bio)
150 {
151 int i;
152
153 for (i = 0; i < conf->raid_disks; i++) {
154 struct bio **bio = r1_bio->bios + i;
155 if (*bio)
156 bio_put(*bio);
157 *bio = NULL;
158 }
159 }
160
161 static inline void free_r1bio(r1bio_t *r1_bio)
162 {
163 unsigned long flags;
164
165 conf_t *conf = mddev_to_conf(r1_bio->mddev);
166
167 /*
168 * Wake up any possible resync thread that waits for the device
169 * to go idle.
170 */
171 spin_lock_irqsave(&conf->resync_lock, flags);
172 if (!--conf->nr_pending) {
173 wake_up(&conf->wait_idle);
174 wake_up(&conf->wait_resume);
175 }
176 spin_unlock_irqrestore(&conf->resync_lock, flags);
177
178 put_all_bios(conf, r1_bio);
179 mempool_free(r1_bio, conf->r1bio_pool);
180 }
181
182 static inline void put_buf(r1bio_t *r1_bio)
183 {
184 conf_t *conf = mddev_to_conf(r1_bio->mddev);
185 unsigned long flags;
186
187 mempool_free(r1_bio, conf->r1buf_pool);
188
189 spin_lock_irqsave(&conf->resync_lock, flags);
190 if (!conf->barrier)
191 BUG();
192 --conf->barrier;
193 wake_up(&conf->wait_resume);
194 wake_up(&conf->wait_idle);
195
196 if (!--conf->nr_pending) {
197 wake_up(&conf->wait_idle);
198 wake_up(&conf->wait_resume);
199 }
200 spin_unlock_irqrestore(&conf->resync_lock, flags);
201 }
202
203 static void reschedule_retry(r1bio_t *r1_bio)
204 {
205 unsigned long flags;
206 mddev_t *mddev = r1_bio->mddev;
207 conf_t *conf = mddev_to_conf(mddev);
208
209 spin_lock_irqsave(&conf->device_lock, flags);
210 list_add(&r1_bio->retry_list, &conf->retry_list);
211 spin_unlock_irqrestore(&conf->device_lock, flags);
212
213 md_wakeup_thread(mddev->thread);
214 }
215
216 /*
217 * raid_end_bio_io() is called when we have finished servicing a mirrored
218 * operation and are ready to return a success/failure code to the buffer
219 * cache layer.
220 */
221 static void raid_end_bio_io(r1bio_t *r1_bio)
222 {
223 struct bio *bio = r1_bio->master_bio;
224
225 /* if nobody has done the final endio yet, do it now */
226 if (!test_and_set_bit(R1BIO_Returned, &r1_bio->state)) {
227 PRINTK(KERN_DEBUG "raid1: sync end %s on sectors %llu-%llu\n",
228 (bio_data_dir(bio) == WRITE) ? "write" : "read",
229 (unsigned long long) bio->bi_sector,
230 (unsigned long long) bio->bi_sector +
231 (bio->bi_size >> 9) - 1);
232
233 bio_endio(bio, bio->bi_size,
234 test_bit(R1BIO_Uptodate, &r1_bio->state) ? 0 : -EIO);
235 }
236 free_r1bio(r1_bio);
237 }
238
239 /*
240 * Update disk head position estimator based on IRQ completion info.
241 */
242 static inline void update_head_pos(int disk, r1bio_t *r1_bio)
243 {
244 conf_t *conf = mddev_to_conf(r1_bio->mddev);
245
246 conf->mirrors[disk].head_position =
247 r1_bio->sector + (r1_bio->sectors);
248 }
249
250 static int raid1_end_read_request(struct bio *bio, unsigned int bytes_done, int error)
251 {
252 int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
253 r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private);
254 int mirror;
255 conf_t *conf = mddev_to_conf(r1_bio->mddev);
256
257 if (bio->bi_size)
258 return 1;
259
260 mirror = r1_bio->read_disk;
261 /*
262 * this branch is our 'one mirror IO has finished' event handler:
263 */
264 if (!uptodate)
265 md_error(r1_bio->mddev, conf->mirrors[mirror].rdev);
266 else
267 /*
268 * Set R1BIO_Uptodate in our master bio, so that
269 * we will return a good error code for to the higher
270 * levels even if IO on some other mirrored buffer fails.
271 *
272 * The 'master' represents the composite IO operation to
273 * user-side. So if something waits for IO, then it will
274 * wait for the 'master' bio.
275 */
276 set_bit(R1BIO_Uptodate, &r1_bio->state);
277
278 update_head_pos(mirror, r1_bio);
279
280 /*
281 * we have only one bio on the read side
282 */
283 if (uptodate)
284 raid_end_bio_io(r1_bio);
285 else {
286 /*
287 * oops, read error:
288 */
289 char b[BDEVNAME_SIZE];
290 if (printk_ratelimit())
291 printk(KERN_ERR "raid1: %s: rescheduling sector %llu\n",
292 bdevname(conf->mirrors[mirror].rdev->bdev,b), (unsigned long long)r1_bio->sector);
293 reschedule_retry(r1_bio);
294 }
295
296 rdev_dec_pending(conf->mirrors[mirror].rdev, conf->mddev);
297 return 0;
298 }
299
300 static int raid1_end_write_request(struct bio *bio, unsigned int bytes_done, int error)
301 {
302 int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
303 r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private);
304 int mirror, behind = test_bit(R1BIO_BehindIO, &r1_bio->state);
305 conf_t *conf = mddev_to_conf(r1_bio->mddev);
306
307 if (bio->bi_size)
308 return 1;
309
310 for (mirror = 0; mirror < conf->raid_disks; mirror++)
311 if (r1_bio->bios[mirror] == bio)
312 break;
313
314 if (error == -ENOTSUPP && test_bit(R1BIO_Barrier, &r1_bio->state)) {
315 set_bit(BarriersNotsupp, &conf->mirrors[mirror].rdev->flags);
316 set_bit(R1BIO_BarrierRetry, &r1_bio->state);
317 r1_bio->mddev->barriers_work = 0;
318 } else {
319 /*
320 * this branch is our 'one mirror IO has finished' event handler:
321 */
322 r1_bio->bios[mirror] = NULL;
323 if (!uptodate) {
324 md_error(r1_bio->mddev, conf->mirrors[mirror].rdev);
325 /* an I/O failed, we can't clear the bitmap */
326 set_bit(R1BIO_Degraded, &r1_bio->state);
327 } else
328 /*
329 * Set R1BIO_Uptodate in our master bio, so that
330 * we will return a good error code for to the higher
331 * levels even if IO on some other mirrored buffer fails.
332 *
333 * The 'master' represents the composite IO operation to
334 * user-side. So if something waits for IO, then it will
335 * wait for the 'master' bio.
336 */
337 set_bit(R1BIO_Uptodate, &r1_bio->state);
338
339 update_head_pos(mirror, r1_bio);
340
341 if (behind) {
342 if (test_bit(WriteMostly, &conf->mirrors[mirror].rdev->flags))
343 atomic_dec(&r1_bio->behind_remaining);
344
345 /* In behind mode, we ACK the master bio once the I/O has safely
346 * reached all non-writemostly disks. Setting the Returned bit
347 * ensures that this gets done only once -- we don't ever want to
348 * return -EIO here, instead we'll wait */
349
350 if (atomic_read(&r1_bio->behind_remaining) >= (atomic_read(&r1_bio->remaining)-1) &&
351 test_bit(R1BIO_Uptodate, &r1_bio->state)) {
352 /* Maybe we can return now */
353 if (!test_and_set_bit(R1BIO_Returned, &r1_bio->state)) {
354 struct bio *mbio = r1_bio->master_bio;
355 PRINTK(KERN_DEBUG "raid1: behind end write sectors %llu-%llu\n",
356 (unsigned long long) mbio->bi_sector,
357 (unsigned long long) mbio->bi_sector +
358 (mbio->bi_size >> 9) - 1);
359 bio_endio(mbio, mbio->bi_size, 0);
360 }
361 }
362 }
363 }
364 /*
365 *
366 * Let's see if all mirrored write operations have finished
367 * already.
368 */
369 if (atomic_dec_and_test(&r1_bio->remaining)) {
370 if (test_bit(R1BIO_BarrierRetry, &r1_bio->state)) {
371 reschedule_retry(r1_bio);
372 /* Don't dec_pending yet, we want to hold
373 * the reference over the retry
374 */
375 return 0;
376 }
377 if (test_bit(R1BIO_BehindIO, &r1_bio->state)) {
378 /* free extra copy of the data pages */
379 int i = bio->bi_vcnt;
380 while (i--)
381 __free_page(bio->bi_io_vec[i].bv_page);
382 }
383 /* clear the bitmap if all writes complete successfully */
384 bitmap_endwrite(r1_bio->mddev->bitmap, r1_bio->sector,
385 r1_bio->sectors,
386 !test_bit(R1BIO_Degraded, &r1_bio->state),
387 behind);
388 md_write_end(r1_bio->mddev);
389 raid_end_bio_io(r1_bio);
390 }
391
392 if (r1_bio->bios[mirror]==NULL)
393 bio_put(bio);
394
395 rdev_dec_pending(conf->mirrors[mirror].rdev, conf->mddev);
396 return 0;
397 }
398
399
400 /*
401 * This routine returns the disk from which the requested read should
402 * be done. There is a per-array 'next expected sequential IO' sector
403 * number - if this matches on the next IO then we use the last disk.
404 * There is also a per-disk 'last know head position' sector that is
405 * maintained from IRQ contexts, both the normal and the resync IO
406 * completion handlers update this position correctly. If there is no
407 * perfect sequential match then we pick the disk whose head is closest.
408 *
409 * If there are 2 mirrors in the same 2 devices, performance degrades
410 * because position is mirror, not device based.
411 *
412 * The rdev for the device selected will have nr_pending incremented.
413 */
414 static int read_balance(conf_t *conf, r1bio_t *r1_bio)
415 {
416 const unsigned long this_sector = r1_bio->sector;
417 int new_disk = conf->last_used, disk = new_disk;
418 int wonly_disk = -1;
419 const int sectors = r1_bio->sectors;
420 sector_t new_distance, current_distance;
421 mdk_rdev_t *rdev;
422
423 rcu_read_lock();
424 /*
425 * Check if we can balance. We can balance on the whole
426 * device if no resync is going on, or below the resync window.
427 * We take the first readable disk when above the resync window.
428 */
429 retry:
430 if (conf->mddev->recovery_cp < MaxSector &&
431 (this_sector + sectors >= conf->next_resync)) {
432 /* Choose the first operation device, for consistancy */
433 new_disk = 0;
434
435 for (rdev = rcu_dereference(conf->mirrors[new_disk].rdev);
436 !rdev || !test_bit(In_sync, &rdev->flags)
437 || test_bit(WriteMostly, &rdev->flags);
438 rdev = rcu_dereference(conf->mirrors[++new_disk].rdev)) {
439
440 if (rdev && test_bit(In_sync, &rdev->flags))
441 wonly_disk = new_disk;
442
443 if (new_disk == conf->raid_disks - 1) {
444 new_disk = wonly_disk;
445 break;
446 }
447 }
448 goto rb_out;
449 }
450
451
452 /* make sure the disk is operational */
453 for (rdev = rcu_dereference(conf->mirrors[new_disk].rdev);
454 !rdev || !test_bit(In_sync, &rdev->flags) ||
455 test_bit(WriteMostly, &rdev->flags);
456 rdev = rcu_dereference(conf->mirrors[new_disk].rdev)) {
457
458 if (rdev && test_bit(In_sync, &rdev->flags))
459 wonly_disk = new_disk;
460
461 if (new_disk <= 0)
462 new_disk = conf->raid_disks;
463 new_disk--;
464 if (new_disk == disk) {
465 new_disk = wonly_disk;
466 break;
467 }
468 }
469
470 if (new_disk < 0)
471 goto rb_out;
472
473 disk = new_disk;
474 /* now disk == new_disk == starting point for search */
475
476 /*
477 * Don't change to another disk for sequential reads:
478 */
479 if (conf->next_seq_sect == this_sector)
480 goto rb_out;
481 if (this_sector == conf->mirrors[new_disk].head_position)
482 goto rb_out;
483
484 current_distance = abs(this_sector - conf->mirrors[disk].head_position);
485
486 /* Find the disk whose head is closest */
487
488 do {
489 if (disk <= 0)
490 disk = conf->raid_disks;
491 disk--;
492
493 rdev = rcu_dereference(conf->mirrors[disk].rdev);
494
495 if (!rdev ||
496 !test_bit(In_sync, &rdev->flags) ||
497 test_bit(WriteMostly, &rdev->flags))
498 continue;
499
500 if (!atomic_read(&rdev->nr_pending)) {
501 new_disk = disk;
502 break;
503 }
504 new_distance = abs(this_sector - conf->mirrors[disk].head_position);
505 if (new_distance < current_distance) {
506 current_distance = new_distance;
507 new_disk = disk;
508 }
509 } while (disk != conf->last_used);
510
511 rb_out:
512
513
514 if (new_disk >= 0) {
515 rdev = rcu_dereference(conf->mirrors[new_disk].rdev);
516 if (!rdev)
517 goto retry;
518 atomic_inc(&rdev->nr_pending);
519 if (!test_bit(In_sync, &rdev->flags)) {
520 /* cannot risk returning a device that failed
521 * before we inc'ed nr_pending
522 */
523 atomic_dec(&rdev->nr_pending);
524 goto retry;
525 }
526 conf->next_seq_sect = this_sector + sectors;
527 conf->last_used = new_disk;
528 }
529 rcu_read_unlock();
530
531 return new_disk;
532 }
533
534 static void unplug_slaves(mddev_t *mddev)
535 {
536 conf_t *conf = mddev_to_conf(mddev);
537 int i;
538
539 rcu_read_lock();
540 for (i=0; i<mddev->raid_disks; i++) {
541 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
542 if (rdev && !test_bit(Faulty, &rdev->flags) && atomic_read(&rdev->nr_pending)) {
543 request_queue_t *r_queue = bdev_get_queue(rdev->bdev);
544
545 atomic_inc(&rdev->nr_pending);
546 rcu_read_unlock();
547
548 if (r_queue->unplug_fn)
549 r_queue->unplug_fn(r_queue);
550
551 rdev_dec_pending(rdev, mddev);
552 rcu_read_lock();
553 }
554 }
555 rcu_read_unlock();
556 }
557
558 static void raid1_unplug(request_queue_t *q)
559 {
560 mddev_t *mddev = q->queuedata;
561
562 unplug_slaves(mddev);
563 md_wakeup_thread(mddev->thread);
564 }
565
566 static int raid1_issue_flush(request_queue_t *q, struct gendisk *disk,
567 sector_t *error_sector)
568 {
569 mddev_t *mddev = q->queuedata;
570 conf_t *conf = mddev_to_conf(mddev);
571 int i, ret = 0;
572
573 rcu_read_lock();
574 for (i=0; i<mddev->raid_disks && ret == 0; i++) {
575 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
576 if (rdev && !test_bit(Faulty, &rdev->flags)) {
577 struct block_device *bdev = rdev->bdev;
578 request_queue_t *r_queue = bdev_get_queue(bdev);
579
580 if (!r_queue->issue_flush_fn)
581 ret = -EOPNOTSUPP;
582 else {
583 atomic_inc(&rdev->nr_pending);
584 rcu_read_unlock();
585 ret = r_queue->issue_flush_fn(r_queue, bdev->bd_disk,
586 error_sector);
587 rdev_dec_pending(rdev, mddev);
588 rcu_read_lock();
589 }
590 }
591 }
592 rcu_read_unlock();
593 return ret;
594 }
595
596 /*
597 * Throttle resync depth, so that we can both get proper overlapping of
598 * requests, but are still able to handle normal requests quickly.
599 */
600 #define RESYNC_DEPTH 32
601
602 static void device_barrier(conf_t *conf, sector_t sect)
603 {
604 spin_lock_irq(&conf->resync_lock);
605 wait_event_lock_irq(conf->wait_idle, !waitqueue_active(&conf->wait_resume),
606 conf->resync_lock, raid1_unplug(conf->mddev->queue));
607
608 if (!conf->barrier++) {
609 wait_event_lock_irq(conf->wait_idle, !conf->nr_pending,
610 conf->resync_lock, raid1_unplug(conf->mddev->queue));
611 if (conf->nr_pending)
612 BUG();
613 }
614 wait_event_lock_irq(conf->wait_resume, conf->barrier < RESYNC_DEPTH,
615 conf->resync_lock, raid1_unplug(conf->mddev->queue));
616 conf->next_resync = sect;
617 spin_unlock_irq(&conf->resync_lock);
618 }
619
620 /* duplicate the data pages for behind I/O */
621 static struct page **alloc_behind_pages(struct bio *bio)
622 {
623 int i;
624 struct bio_vec *bvec;
625 struct page **pages = kmalloc(bio->bi_vcnt * sizeof(struct page *),
626 GFP_NOIO);
627 if (unlikely(!pages))
628 goto do_sync_io;
629
630 memset(pages, 0, bio->bi_vcnt * sizeof(struct page *));
631
632 bio_for_each_segment(bvec, bio, i) {
633 pages[i] = alloc_page(GFP_NOIO);
634 if (unlikely(!pages[i]))
635 goto do_sync_io;
636 memcpy(kmap(pages[i]) + bvec->bv_offset,
637 kmap(bvec->bv_page) + bvec->bv_offset, bvec->bv_len);
638 kunmap(pages[i]);
639 kunmap(bvec->bv_page);
640 }
641
642 return pages;
643
644 do_sync_io:
645 if (pages)
646 for (i = 0; i < bio->bi_vcnt && pages[i]; i++)
647 __free_page(pages[i]);
648 kfree(pages);
649 PRINTK("%dB behind alloc failed, doing sync I/O\n", bio->bi_size);
650 return NULL;
651 }
652
653 static int make_request(request_queue_t *q, struct bio * bio)
654 {
655 mddev_t *mddev = q->queuedata;
656 conf_t *conf = mddev_to_conf(mddev);
657 mirror_info_t *mirror;
658 r1bio_t *r1_bio;
659 struct bio *read_bio;
660 int i, targets = 0, disks;
661 mdk_rdev_t *rdev;
662 struct bitmap *bitmap = mddev->bitmap;
663 unsigned long flags;
664 struct bio_list bl;
665 struct page **behind_pages = NULL;
666 const int rw = bio_data_dir(bio);
667 int do_barriers;
668
669 if (unlikely(!mddev->barriers_work && bio_barrier(bio))) {
670 bio_endio(bio, bio->bi_size, -EOPNOTSUPP);
671 return 0;
672 }
673
674 /*
675 * Register the new request and wait if the reconstruction
676 * thread has put up a bar for new requests.
677 * Continue immediately if no resync is active currently.
678 */
679 md_write_start(mddev, bio); /* wait on superblock update early */
680
681 spin_lock_irq(&conf->resync_lock);
682 wait_event_lock_irq(conf->wait_resume, !conf->barrier, conf->resync_lock, );
683 conf->nr_pending++;
684 spin_unlock_irq(&conf->resync_lock);
685
686 disk_stat_inc(mddev->gendisk, ios[rw]);
687 disk_stat_add(mddev->gendisk, sectors[rw], bio_sectors(bio));
688
689 /*
690 * make_request() can abort the operation when READA is being
691 * used and no empty request is available.
692 *
693 */
694 r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
695
696 r1_bio->master_bio = bio;
697 r1_bio->sectors = bio->bi_size >> 9;
698 r1_bio->state = 0;
699 r1_bio->mddev = mddev;
700 r1_bio->sector = bio->bi_sector;
701
702 if (rw == READ) {
703 /*
704 * read balancing logic:
705 */
706 int rdisk = read_balance(conf, r1_bio);
707
708 if (rdisk < 0) {
709 /* couldn't find anywhere to read from */
710 raid_end_bio_io(r1_bio);
711 return 0;
712 }
713 mirror = conf->mirrors + rdisk;
714
715 r1_bio->read_disk = rdisk;
716
717 read_bio = bio_clone(bio, GFP_NOIO);
718
719 r1_bio->bios[rdisk] = read_bio;
720
721 read_bio->bi_sector = r1_bio->sector + mirror->rdev->data_offset;
722 read_bio->bi_bdev = mirror->rdev->bdev;
723 read_bio->bi_end_io = raid1_end_read_request;
724 read_bio->bi_rw = READ;
725 read_bio->bi_private = r1_bio;
726
727 generic_make_request(read_bio);
728 return 0;
729 }
730
731 /*
732 * WRITE:
733 */
734 /* first select target devices under spinlock and
735 * inc refcount on their rdev. Record them by setting
736 * bios[x] to bio
737 */
738 disks = conf->raid_disks;
739 #if 0
740 { static int first=1;
741 if (first) printk("First Write sector %llu disks %d\n",
742 (unsigned long long)r1_bio->sector, disks);
743 first = 0;
744 }
745 #endif
746 rcu_read_lock();
747 for (i = 0; i < disks; i++) {
748 if ((rdev=rcu_dereference(conf->mirrors[i].rdev)) != NULL &&
749 !test_bit(Faulty, &rdev->flags)) {
750 atomic_inc(&rdev->nr_pending);
751 if (test_bit(Faulty, &rdev->flags)) {
752 atomic_dec(&rdev->nr_pending);
753 r1_bio->bios[i] = NULL;
754 } else
755 r1_bio->bios[i] = bio;
756 targets++;
757 } else
758 r1_bio->bios[i] = NULL;
759 }
760 rcu_read_unlock();
761
762 BUG_ON(targets == 0); /* we never fail the last device */
763
764 if (targets < conf->raid_disks) {
765 /* array is degraded, we will not clear the bitmap
766 * on I/O completion (see raid1_end_write_request) */
767 set_bit(R1BIO_Degraded, &r1_bio->state);
768 }
769
770 /* do behind I/O ? */
771 if (bitmap &&
772 atomic_read(&bitmap->behind_writes) < bitmap->max_write_behind &&
773 (behind_pages = alloc_behind_pages(bio)) != NULL)
774 set_bit(R1BIO_BehindIO, &r1_bio->state);
775
776 atomic_set(&r1_bio->remaining, 0);
777 atomic_set(&r1_bio->behind_remaining, 0);
778
779 do_barriers = bio->bi_rw & BIO_RW_BARRIER;
780 if (do_barriers)
781 set_bit(R1BIO_Barrier, &r1_bio->state);
782
783 bio_list_init(&bl);
784 for (i = 0; i < disks; i++) {
785 struct bio *mbio;
786 if (!r1_bio->bios[i])
787 continue;
788
789 mbio = bio_clone(bio, GFP_NOIO);
790 r1_bio->bios[i] = mbio;
791
792 mbio->bi_sector = r1_bio->sector + conf->mirrors[i].rdev->data_offset;
793 mbio->bi_bdev = conf->mirrors[i].rdev->bdev;
794 mbio->bi_end_io = raid1_end_write_request;
795 mbio->bi_rw = WRITE | do_barriers;
796 mbio->bi_private = r1_bio;
797
798 if (behind_pages) {
799 struct bio_vec *bvec;
800 int j;
801
802 /* Yes, I really want the '__' version so that
803 * we clear any unused pointer in the io_vec, rather
804 * than leave them unchanged. This is important
805 * because when we come to free the pages, we won't
806 * know the originial bi_idx, so we just free
807 * them all
808 */
809 __bio_for_each_segment(bvec, mbio, j, 0)
810 bvec->bv_page = behind_pages[j];
811 if (test_bit(WriteMostly, &conf->mirrors[i].rdev->flags))
812 atomic_inc(&r1_bio->behind_remaining);
813 }
814
815 atomic_inc(&r1_bio->remaining);
816
817 bio_list_add(&bl, mbio);
818 }
819 kfree(behind_pages); /* the behind pages are attached to the bios now */
820
821 bitmap_startwrite(bitmap, bio->bi_sector, r1_bio->sectors,
822 test_bit(R1BIO_BehindIO, &r1_bio->state));
823 spin_lock_irqsave(&conf->device_lock, flags);
824 bio_list_merge(&conf->pending_bio_list, &bl);
825 bio_list_init(&bl);
826
827 blk_plug_device(mddev->queue);
828 spin_unlock_irqrestore(&conf->device_lock, flags);
829
830 #if 0
831 while ((bio = bio_list_pop(&bl)) != NULL)
832 generic_make_request(bio);
833 #endif
834
835 return 0;
836 }
837
838 static void status(struct seq_file *seq, mddev_t *mddev)
839 {
840 conf_t *conf = mddev_to_conf(mddev);
841 int i;
842
843 seq_printf(seq, " [%d/%d] [", conf->raid_disks,
844 conf->working_disks);
845 for (i = 0; i < conf->raid_disks; i++)
846 seq_printf(seq, "%s",
847 conf->mirrors[i].rdev &&
848 test_bit(In_sync, &conf->mirrors[i].rdev->flags) ? "U" : "_");
849 seq_printf(seq, "]");
850 }
851
852
853 static void error(mddev_t *mddev, mdk_rdev_t *rdev)
854 {
855 char b[BDEVNAME_SIZE];
856 conf_t *conf = mddev_to_conf(mddev);
857
858 /*
859 * If it is not operational, then we have already marked it as dead
860 * else if it is the last working disks, ignore the error, let the
861 * next level up know.
862 * else mark the drive as failed
863 */
864 if (test_bit(In_sync, &rdev->flags)
865 && conf->working_disks == 1)
866 /*
867 * Don't fail the drive, act as though we were just a
868 * normal single drive
869 */
870 return;
871 if (test_bit(In_sync, &rdev->flags)) {
872 mddev->degraded++;
873 conf->working_disks--;
874 /*
875 * if recovery is running, make sure it aborts.
876 */
877 set_bit(MD_RECOVERY_ERR, &mddev->recovery);
878 }
879 clear_bit(In_sync, &rdev->flags);
880 set_bit(Faulty, &rdev->flags);
881 mddev->sb_dirty = 1;
882 printk(KERN_ALERT "raid1: Disk failure on %s, disabling device. \n"
883 " Operation continuing on %d devices\n",
884 bdevname(rdev->bdev,b), conf->working_disks);
885 }
886
887 static void print_conf(conf_t *conf)
888 {
889 int i;
890 mirror_info_t *tmp;
891
892 printk("RAID1 conf printout:\n");
893 if (!conf) {
894 printk("(!conf)\n");
895 return;
896 }
897 printk(" --- wd:%d rd:%d\n", conf->working_disks,
898 conf->raid_disks);
899
900 for (i = 0; i < conf->raid_disks; i++) {
901 char b[BDEVNAME_SIZE];
902 tmp = conf->mirrors + i;
903 if (tmp->rdev)
904 printk(" disk %d, wo:%d, o:%d, dev:%s\n",
905 i, !test_bit(In_sync, &tmp->rdev->flags), !test_bit(Faulty, &tmp->rdev->flags),
906 bdevname(tmp->rdev->bdev,b));
907 }
908 }
909
910 static void close_sync(conf_t *conf)
911 {
912 spin_lock_irq(&conf->resync_lock);
913 wait_event_lock_irq(conf->wait_resume, !conf->barrier,
914 conf->resync_lock, raid1_unplug(conf->mddev->queue));
915 spin_unlock_irq(&conf->resync_lock);
916
917 if (conf->barrier) BUG();
918 if (waitqueue_active(&conf->wait_idle)) BUG();
919
920 mempool_destroy(conf->r1buf_pool);
921 conf->r1buf_pool = NULL;
922 }
923
924 static int raid1_spare_active(mddev_t *mddev)
925 {
926 int i;
927 conf_t *conf = mddev->private;
928 mirror_info_t *tmp;
929
930 /*
931 * Find all failed disks within the RAID1 configuration
932 * and mark them readable
933 */
934 for (i = 0; i < conf->raid_disks; i++) {
935 tmp = conf->mirrors + i;
936 if (tmp->rdev
937 && !test_bit(Faulty, &tmp->rdev->flags)
938 && !test_bit(In_sync, &tmp->rdev->flags)) {
939 conf->working_disks++;
940 mddev->degraded--;
941 set_bit(In_sync, &tmp->rdev->flags);
942 }
943 }
944
945 print_conf(conf);
946 return 0;
947 }
948
949
950 static int raid1_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
951 {
952 conf_t *conf = mddev->private;
953 int found = 0;
954 int mirror = 0;
955 mirror_info_t *p;
956
957 for (mirror=0; mirror < mddev->raid_disks; mirror++)
958 if ( !(p=conf->mirrors+mirror)->rdev) {
959
960 blk_queue_stack_limits(mddev->queue,
961 rdev->bdev->bd_disk->queue);
962 /* as we don't honour merge_bvec_fn, we must never risk
963 * violating it, so limit ->max_sector to one PAGE, as
964 * a one page request is never in violation.
965 */
966 if (rdev->bdev->bd_disk->queue->merge_bvec_fn &&
967 mddev->queue->max_sectors > (PAGE_SIZE>>9))
968 blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9);
969
970 p->head_position = 0;
971 rdev->raid_disk = mirror;
972 found = 1;
973 /* As all devices are equivalent, we don't need a full recovery
974 * if this was recently any drive of the array
975 */
976 if (rdev->saved_raid_disk < 0)
977 conf->fullsync = 1;
978 rcu_assign_pointer(p->rdev, rdev);
979 break;
980 }
981
982 print_conf(conf);
983 return found;
984 }
985
986 static int raid1_remove_disk(mddev_t *mddev, int number)
987 {
988 conf_t *conf = mddev->private;
989 int err = 0;
990 mdk_rdev_t *rdev;
991 mirror_info_t *p = conf->mirrors+ number;
992
993 print_conf(conf);
994 rdev = p->rdev;
995 if (rdev) {
996 if (test_bit(In_sync, &rdev->flags) ||
997 atomic_read(&rdev->nr_pending)) {
998 err = -EBUSY;
999 goto abort;
1000 }
1001 p->rdev = NULL;
1002 synchronize_rcu();
1003 if (atomic_read(&rdev->nr_pending)) {
1004 /* lost the race, try later */
1005 err = -EBUSY;
1006 p->rdev = rdev;
1007 }
1008 }
1009 abort:
1010
1011 print_conf(conf);
1012 return err;
1013 }
1014
1015
1016 static int end_sync_read(struct bio *bio, unsigned int bytes_done, int error)
1017 {
1018 int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
1019 r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private);
1020 conf_t *conf = mddev_to_conf(r1_bio->mddev);
1021
1022 if (bio->bi_size)
1023 return 1;
1024
1025 if (r1_bio->bios[r1_bio->read_disk] != bio)
1026 BUG();
1027 update_head_pos(r1_bio->read_disk, r1_bio);
1028 /*
1029 * we have read a block, now it needs to be re-written,
1030 * or re-read if the read failed.
1031 * We don't do much here, just schedule handling by raid1d
1032 */
1033 if (!uptodate) {
1034 md_error(r1_bio->mddev,
1035 conf->mirrors[r1_bio->read_disk].rdev);
1036 } else
1037 set_bit(R1BIO_Uptodate, &r1_bio->state);
1038 rdev_dec_pending(conf->mirrors[r1_bio->read_disk].rdev, conf->mddev);
1039 reschedule_retry(r1_bio);
1040 return 0;
1041 }
1042
1043 static int end_sync_write(struct bio *bio, unsigned int bytes_done, int error)
1044 {
1045 int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
1046 r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private);
1047 mddev_t *mddev = r1_bio->mddev;
1048 conf_t *conf = mddev_to_conf(mddev);
1049 int i;
1050 int mirror=0;
1051
1052 if (bio->bi_size)
1053 return 1;
1054
1055 for (i = 0; i < conf->raid_disks; i++)
1056 if (r1_bio->bios[i] == bio) {
1057 mirror = i;
1058 break;
1059 }
1060 if (!uptodate)
1061 md_error(mddev, conf->mirrors[mirror].rdev);
1062
1063 update_head_pos(mirror, r1_bio);
1064
1065 if (atomic_dec_and_test(&r1_bio->remaining)) {
1066 md_done_sync(mddev, r1_bio->sectors, uptodate);
1067 put_buf(r1_bio);
1068 }
1069 rdev_dec_pending(conf->mirrors[mirror].rdev, mddev);
1070 return 0;
1071 }
1072
1073 static void sync_request_write(mddev_t *mddev, r1bio_t *r1_bio)
1074 {
1075 conf_t *conf = mddev_to_conf(mddev);
1076 int i;
1077 int disks = conf->raid_disks;
1078 struct bio *bio, *wbio;
1079
1080 bio = r1_bio->bios[r1_bio->read_disk];
1081
1082 /*
1083 if (r1_bio->sector == 0) printk("First sync write startss\n");
1084 */
1085 /*
1086 * schedule writes
1087 */
1088 if (!test_bit(R1BIO_Uptodate, &r1_bio->state)) {
1089 /*
1090 * There is no point trying a read-for-reconstruct as
1091 * reconstruct is about to be aborted
1092 */
1093 char b[BDEVNAME_SIZE];
1094 printk(KERN_ALERT "raid1: %s: unrecoverable I/O read error"
1095 " for block %llu\n",
1096 bdevname(bio->bi_bdev,b),
1097 (unsigned long long)r1_bio->sector);
1098 md_done_sync(mddev, r1_bio->sectors, 0);
1099 put_buf(r1_bio);
1100 return;
1101 }
1102
1103 atomic_set(&r1_bio->remaining, 1);
1104 for (i = 0; i < disks ; i++) {
1105 wbio = r1_bio->bios[i];
1106 if (wbio->bi_end_io != end_sync_write)
1107 continue;
1108
1109 atomic_inc(&conf->mirrors[i].rdev->nr_pending);
1110 atomic_inc(&r1_bio->remaining);
1111 md_sync_acct(conf->mirrors[i].rdev->bdev, wbio->bi_size >> 9);
1112
1113 generic_make_request(wbio);
1114 }
1115
1116 if (atomic_dec_and_test(&r1_bio->remaining)) {
1117 /* if we're here, all write(s) have completed, so clean up */
1118 md_done_sync(mddev, r1_bio->sectors, 1);
1119 put_buf(r1_bio);
1120 }
1121 }
1122
1123 /*
1124 * This is a kernel thread which:
1125 *
1126 * 1. Retries failed read operations on working mirrors.
1127 * 2. Updates the raid superblock when problems encounter.
1128 * 3. Performs writes following reads for array syncronising.
1129 */
1130
1131 static void raid1d(mddev_t *mddev)
1132 {
1133 r1bio_t *r1_bio;
1134 struct bio *bio;
1135 unsigned long flags;
1136 conf_t *conf = mddev_to_conf(mddev);
1137 struct list_head *head = &conf->retry_list;
1138 int unplug=0;
1139 mdk_rdev_t *rdev;
1140
1141 md_check_recovery(mddev);
1142
1143 for (;;) {
1144 char b[BDEVNAME_SIZE];
1145 spin_lock_irqsave(&conf->device_lock, flags);
1146
1147 if (conf->pending_bio_list.head) {
1148 bio = bio_list_get(&conf->pending_bio_list);
1149 blk_remove_plug(mddev->queue);
1150 spin_unlock_irqrestore(&conf->device_lock, flags);
1151 /* flush any pending bitmap writes to disk before proceeding w/ I/O */
1152 if (bitmap_unplug(mddev->bitmap) != 0)
1153 printk("%s: bitmap file write failed!\n", mdname(mddev));
1154
1155 while (bio) { /* submit pending writes */
1156 struct bio *next = bio->bi_next;
1157 bio->bi_next = NULL;
1158 generic_make_request(bio);
1159 bio = next;
1160 }
1161 unplug = 1;
1162
1163 continue;
1164 }
1165
1166 if (list_empty(head))
1167 break;
1168 r1_bio = list_entry(head->prev, r1bio_t, retry_list);
1169 list_del(head->prev);
1170 spin_unlock_irqrestore(&conf->device_lock, flags);
1171
1172 mddev = r1_bio->mddev;
1173 conf = mddev_to_conf(mddev);
1174 if (test_bit(R1BIO_IsSync, &r1_bio->state)) {
1175 sync_request_write(mddev, r1_bio);
1176 unplug = 1;
1177 } else if (test_bit(R1BIO_BarrierRetry, &r1_bio->state)) {
1178 /* some requests in the r1bio were BIO_RW_BARRIER
1179 * requests which failed with -ENOTSUPP. Hohumm..
1180 * Better resubmit without the barrier.
1181 * We know which devices to resubmit for, because
1182 * all others have had their bios[] entry cleared.
1183 */
1184 int i;
1185 clear_bit(R1BIO_BarrierRetry, &r1_bio->state);
1186 clear_bit(R1BIO_Barrier, &r1_bio->state);
1187 for (i=0; i < conf->raid_disks; i++)
1188 if (r1_bio->bios[i]) {
1189 struct bio_vec *bvec;
1190 int j;
1191
1192 bio = bio_clone(r1_bio->master_bio, GFP_NOIO);
1193 /* copy pages from the failed bio, as
1194 * this might be a write-behind device */
1195 __bio_for_each_segment(bvec, bio, j, 0)
1196 bvec->bv_page = bio_iovec_idx(r1_bio->bios[i], j)->bv_page;
1197 bio_put(r1_bio->bios[i]);
1198 bio->bi_sector = r1_bio->sector +
1199 conf->mirrors[i].rdev->data_offset;
1200 bio->bi_bdev = conf->mirrors[i].rdev->bdev;
1201 bio->bi_end_io = raid1_end_write_request;
1202 bio->bi_rw = WRITE;
1203 bio->bi_private = r1_bio;
1204 r1_bio->bios[i] = bio;
1205 generic_make_request(bio);
1206 }
1207 } else {
1208 int disk;
1209 bio = r1_bio->bios[r1_bio->read_disk];
1210 if ((disk=read_balance(conf, r1_bio)) == -1) {
1211 printk(KERN_ALERT "raid1: %s: unrecoverable I/O"
1212 " read error for block %llu\n",
1213 bdevname(bio->bi_bdev,b),
1214 (unsigned long long)r1_bio->sector);
1215 raid_end_bio_io(r1_bio);
1216 } else {
1217 r1_bio->bios[r1_bio->read_disk] = NULL;
1218 r1_bio->read_disk = disk;
1219 bio_put(bio);
1220 bio = bio_clone(r1_bio->master_bio, GFP_NOIO);
1221 r1_bio->bios[r1_bio->read_disk] = bio;
1222 rdev = conf->mirrors[disk].rdev;
1223 if (printk_ratelimit())
1224 printk(KERN_ERR "raid1: %s: redirecting sector %llu to"
1225 " another mirror\n",
1226 bdevname(rdev->bdev,b),
1227 (unsigned long long)r1_bio->sector);
1228 bio->bi_sector = r1_bio->sector + rdev->data_offset;
1229 bio->bi_bdev = rdev->bdev;
1230 bio->bi_end_io = raid1_end_read_request;
1231 bio->bi_rw = READ;
1232 bio->bi_private = r1_bio;
1233 unplug = 1;
1234 generic_make_request(bio);
1235 }
1236 }
1237 }
1238 spin_unlock_irqrestore(&conf->device_lock, flags);
1239 if (unplug)
1240 unplug_slaves(mddev);
1241 }
1242
1243
1244 static int init_resync(conf_t *conf)
1245 {
1246 int buffs;
1247
1248 buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE;
1249 if (conf->r1buf_pool)
1250 BUG();
1251 conf->r1buf_pool = mempool_create(buffs, r1buf_pool_alloc, r1buf_pool_free,
1252 conf->poolinfo);
1253 if (!conf->r1buf_pool)
1254 return -ENOMEM;
1255 conf->next_resync = 0;
1256 return 0;
1257 }
1258
1259 /*
1260 * perform a "sync" on one "block"
1261 *
1262 * We need to make sure that no normal I/O request - particularly write
1263 * requests - conflict with active sync requests.
1264 *
1265 * This is achieved by tracking pending requests and a 'barrier' concept
1266 * that can be installed to exclude normal IO requests.
1267 */
1268
1269 static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster)
1270 {
1271 conf_t *conf = mddev_to_conf(mddev);
1272 mirror_info_t *mirror;
1273 r1bio_t *r1_bio;
1274 struct bio *bio;
1275 sector_t max_sector, nr_sectors;
1276 int disk;
1277 int i;
1278 int wonly;
1279 int write_targets = 0;
1280 int sync_blocks;
1281 int still_degraded = 0;
1282
1283 if (!conf->r1buf_pool)
1284 {
1285 /*
1286 printk("sync start - bitmap %p\n", mddev->bitmap);
1287 */
1288 if (init_resync(conf))
1289 return 0;
1290 }
1291
1292 max_sector = mddev->size << 1;
1293 if (sector_nr >= max_sector) {
1294 /* If we aborted, we need to abort the
1295 * sync on the 'current' bitmap chunk (there will
1296 * only be one in raid1 resync.
1297 * We can find the current addess in mddev->curr_resync
1298 */
1299 if (mddev->curr_resync < max_sector) /* aborted */
1300 bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
1301 &sync_blocks, 1);
1302 else /* completed sync */
1303 conf->fullsync = 0;
1304
1305 bitmap_close_sync(mddev->bitmap);
1306 close_sync(conf);
1307 return 0;
1308 }
1309
1310 /* before building a request, check if we can skip these blocks..
1311 * This call the bitmap_start_sync doesn't actually record anything
1312 */
1313 if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
1314 !conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
1315 /* We can skip this block, and probably several more */
1316 *skipped = 1;
1317 return sync_blocks;
1318 }
1319 /*
1320 * If there is non-resync activity waiting for us then
1321 * put in a delay to throttle resync.
1322 */
1323 if (!go_faster && waitqueue_active(&conf->wait_resume))
1324 msleep_interruptible(1000);
1325 device_barrier(conf, sector_nr + RESYNC_SECTORS);
1326
1327 /*
1328 * If reconstructing, and >1 working disc,
1329 * could dedicate one to rebuild and others to
1330 * service read requests ..
1331 */
1332 disk = conf->last_used;
1333 /* make sure disk is operational */
1334 wonly = disk;
1335 while (conf->mirrors[disk].rdev == NULL ||
1336 !test_bit(In_sync, &conf->mirrors[disk].rdev->flags) ||
1337 test_bit(WriteMostly, &conf->mirrors[disk].rdev->flags)
1338 ) {
1339 if (conf->mirrors[disk].rdev &&
1340 test_bit(In_sync, &conf->mirrors[disk].rdev->flags))
1341 wonly = disk;
1342 if (disk <= 0)
1343 disk = conf->raid_disks;
1344 disk--;
1345 if (disk == conf->last_used) {
1346 disk = wonly;
1347 break;
1348 }
1349 }
1350 conf->last_used = disk;
1351 atomic_inc(&conf->mirrors[disk].rdev->nr_pending);
1352
1353
1354 mirror = conf->mirrors + disk;
1355
1356 r1_bio = mempool_alloc(conf->r1buf_pool, GFP_NOIO);
1357
1358 spin_lock_irq(&conf->resync_lock);
1359 conf->nr_pending++;
1360 spin_unlock_irq(&conf->resync_lock);
1361
1362 r1_bio->mddev = mddev;
1363 r1_bio->sector = sector_nr;
1364 r1_bio->state = 0;
1365 set_bit(R1BIO_IsSync, &r1_bio->state);
1366 r1_bio->read_disk = disk;
1367
1368 for (i=0; i < conf->raid_disks; i++) {
1369 bio = r1_bio->bios[i];
1370
1371 /* take from bio_init */
1372 bio->bi_next = NULL;
1373 bio->bi_flags |= 1 << BIO_UPTODATE;
1374 bio->bi_rw = 0;
1375 bio->bi_vcnt = 0;
1376 bio->bi_idx = 0;
1377 bio->bi_phys_segments = 0;
1378 bio->bi_hw_segments = 0;
1379 bio->bi_size = 0;
1380 bio->bi_end_io = NULL;
1381 bio->bi_private = NULL;
1382
1383 if (i == disk) {
1384 bio->bi_rw = READ;
1385 bio->bi_end_io = end_sync_read;
1386 } else if (conf->mirrors[i].rdev == NULL ||
1387 test_bit(Faulty, &conf->mirrors[i].rdev->flags)) {
1388 still_degraded = 1;
1389 continue;
1390 } else if (!test_bit(In_sync, &conf->mirrors[i].rdev->flags) ||
1391 sector_nr + RESYNC_SECTORS > mddev->recovery_cp ||
1392 test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
1393 bio->bi_rw = WRITE;
1394 bio->bi_end_io = end_sync_write;
1395 write_targets ++;
1396 } else
1397 /* no need to read or write here */
1398 continue;
1399 bio->bi_sector = sector_nr + conf->mirrors[i].rdev->data_offset;
1400 bio->bi_bdev = conf->mirrors[i].rdev->bdev;
1401 bio->bi_private = r1_bio;
1402 }
1403
1404 if (write_targets == 0) {
1405 /* There is nowhere to write, so all non-sync
1406 * drives must be failed - so we are finished
1407 */
1408 sector_t rv = max_sector - sector_nr;
1409 *skipped = 1;
1410 put_buf(r1_bio);
1411 rdev_dec_pending(conf->mirrors[disk].rdev, mddev);
1412 return rv;
1413 }
1414
1415 nr_sectors = 0;
1416 sync_blocks = 0;
1417 do {
1418 struct page *page;
1419 int len = PAGE_SIZE;
1420 if (sector_nr + (len>>9) > max_sector)
1421 len = (max_sector - sector_nr) << 9;
1422 if (len == 0)
1423 break;
1424 if (sync_blocks == 0) {
1425 if (!bitmap_start_sync(mddev->bitmap, sector_nr,
1426 &sync_blocks, still_degraded) &&
1427 !conf->fullsync &&
1428 !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
1429 break;
1430 if (sync_blocks < (PAGE_SIZE>>9))
1431 BUG();
1432 if (len > (sync_blocks<<9))
1433 len = sync_blocks<<9;
1434 }
1435
1436 for (i=0 ; i < conf->raid_disks; i++) {
1437 bio = r1_bio->bios[i];
1438 if (bio->bi_end_io) {
1439 page = r1_bio->bios[0]->bi_io_vec[bio->bi_vcnt].bv_page;
1440 if (bio_add_page(bio, page, len, 0) == 0) {
1441 /* stop here */
1442 r1_bio->bios[0]->bi_io_vec[bio->bi_vcnt].bv_page = page;
1443 while (i > 0) {
1444 i--;
1445 bio = r1_bio->bios[i];
1446 if (bio->bi_end_io==NULL)
1447 continue;
1448 /* remove last page from this bio */
1449 bio->bi_vcnt--;
1450 bio->bi_size -= len;
1451 bio->bi_flags &= ~(1<< BIO_SEG_VALID);
1452 }
1453 goto bio_full;
1454 }
1455 }
1456 }
1457 nr_sectors += len>>9;
1458 sector_nr += len>>9;
1459 sync_blocks -= (len>>9);
1460 } while (r1_bio->bios[disk]->bi_vcnt < RESYNC_PAGES);
1461 bio_full:
1462 bio = r1_bio->bios[disk];
1463 r1_bio->sectors = nr_sectors;
1464
1465 md_sync_acct(mirror->rdev->bdev, nr_sectors);
1466
1467 generic_make_request(bio);
1468
1469 return nr_sectors;
1470 }
1471
1472 static int run(mddev_t *mddev)
1473 {
1474 conf_t *conf;
1475 int i, j, disk_idx;
1476 mirror_info_t *disk;
1477 mdk_rdev_t *rdev;
1478 struct list_head *tmp;
1479
1480 if (mddev->level != 1) {
1481 printk("raid1: %s: raid level not set to mirroring (%d)\n",
1482 mdname(mddev), mddev->level);
1483 goto out;
1484 }
1485 /*
1486 * copy the already verified devices into our private RAID1
1487 * bookkeeping area. [whatever we allocate in run(),
1488 * should be freed in stop()]
1489 */
1490 conf = kmalloc(sizeof(conf_t), GFP_KERNEL);
1491 mddev->private = conf;
1492 if (!conf)
1493 goto out_no_mem;
1494
1495 memset(conf, 0, sizeof(*conf));
1496 conf->mirrors = kmalloc(sizeof(struct mirror_info)*mddev->raid_disks,
1497 GFP_KERNEL);
1498 if (!conf->mirrors)
1499 goto out_no_mem;
1500
1501 memset(conf->mirrors, 0, sizeof(struct mirror_info)*mddev->raid_disks);
1502
1503 conf->poolinfo = kmalloc(sizeof(*conf->poolinfo), GFP_KERNEL);
1504 if (!conf->poolinfo)
1505 goto out_no_mem;
1506 conf->poolinfo->mddev = mddev;
1507 conf->poolinfo->raid_disks = mddev->raid_disks;
1508 conf->r1bio_pool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc,
1509 r1bio_pool_free,
1510 conf->poolinfo);
1511 if (!conf->r1bio_pool)
1512 goto out_no_mem;
1513
1514 ITERATE_RDEV(mddev, rdev, tmp) {
1515 disk_idx = rdev->raid_disk;
1516 if (disk_idx >= mddev->raid_disks
1517 || disk_idx < 0)
1518 continue;
1519 disk = conf->mirrors + disk_idx;
1520
1521 disk->rdev = rdev;
1522
1523 blk_queue_stack_limits(mddev->queue,
1524 rdev->bdev->bd_disk->queue);
1525 /* as we don't honour merge_bvec_fn, we must never risk
1526 * violating it, so limit ->max_sector to one PAGE, as
1527 * a one page request is never in violation.
1528 */
1529 if (rdev->bdev->bd_disk->queue->merge_bvec_fn &&
1530 mddev->queue->max_sectors > (PAGE_SIZE>>9))
1531 blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9);
1532
1533 disk->head_position = 0;
1534 if (!test_bit(Faulty, &rdev->flags) && test_bit(In_sync, &rdev->flags))
1535 conf->working_disks++;
1536 }
1537 conf->raid_disks = mddev->raid_disks;
1538 conf->mddev = mddev;
1539 spin_lock_init(&conf->device_lock);
1540 INIT_LIST_HEAD(&conf->retry_list);
1541 if (conf->working_disks == 1)
1542 mddev->recovery_cp = MaxSector;
1543
1544 spin_lock_init(&conf->resync_lock);
1545 init_waitqueue_head(&conf->wait_idle);
1546 init_waitqueue_head(&conf->wait_resume);
1547
1548 bio_list_init(&conf->pending_bio_list);
1549 bio_list_init(&conf->flushing_bio_list);
1550
1551 if (!conf->working_disks) {
1552 printk(KERN_ERR "raid1: no operational mirrors for %s\n",
1553 mdname(mddev));
1554 goto out_free_conf;
1555 }
1556
1557 mddev->degraded = 0;
1558 for (i = 0; i < conf->raid_disks; i++) {
1559
1560 disk = conf->mirrors + i;
1561
1562 if (!disk->rdev) {
1563 disk->head_position = 0;
1564 mddev->degraded++;
1565 }
1566 }
1567
1568 /*
1569 * find the first working one and use it as a starting point
1570 * to read balancing.
1571 */
1572 for (j = 0; j < conf->raid_disks &&
1573 (!conf->mirrors[j].rdev ||
1574 !test_bit(In_sync, &conf->mirrors[j].rdev->flags)) ; j++)
1575 /* nothing */;
1576 conf->last_used = j;
1577
1578
1579 mddev->thread = md_register_thread(raid1d, mddev, "%s_raid1");
1580 if (!mddev->thread) {
1581 printk(KERN_ERR
1582 "raid1: couldn't allocate thread for %s\n",
1583 mdname(mddev));
1584 goto out_free_conf;
1585 }
1586 if (mddev->bitmap) mddev->thread->timeout = mddev->bitmap->daemon_sleep * HZ;
1587
1588 printk(KERN_INFO
1589 "raid1: raid set %s active with %d out of %d mirrors\n",
1590 mdname(mddev), mddev->raid_disks - mddev->degraded,
1591 mddev->raid_disks);
1592 /*
1593 * Ok, everything is just fine now
1594 */
1595 mddev->array_size = mddev->size;
1596
1597 mddev->queue->unplug_fn = raid1_unplug;
1598 mddev->queue->issue_flush_fn = raid1_issue_flush;
1599
1600 return 0;
1601
1602 out_no_mem:
1603 printk(KERN_ERR "raid1: couldn't allocate memory for %s\n",
1604 mdname(mddev));
1605
1606 out_free_conf:
1607 if (conf) {
1608 if (conf->r1bio_pool)
1609 mempool_destroy(conf->r1bio_pool);
1610 kfree(conf->mirrors);
1611 kfree(conf->poolinfo);
1612 kfree(conf);
1613 mddev->private = NULL;
1614 }
1615 out:
1616 return -EIO;
1617 }
1618
1619 static int stop(mddev_t *mddev)
1620 {
1621 conf_t *conf = mddev_to_conf(mddev);
1622 struct bitmap *bitmap = mddev->bitmap;
1623 int behind_wait = 0;
1624
1625 /* wait for behind writes to complete */
1626 while (bitmap && atomic_read(&bitmap->behind_writes) > 0) {
1627 behind_wait++;
1628 printk(KERN_INFO "raid1: behind writes in progress on device %s, waiting to stop (%d)\n", mdname(mddev), behind_wait);
1629 set_current_state(TASK_UNINTERRUPTIBLE);
1630 schedule_timeout(HZ); /* wait a second */
1631 /* need to kick something here to make sure I/O goes? */
1632 }
1633
1634 md_unregister_thread(mddev->thread);
1635 mddev->thread = NULL;
1636 blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
1637 if (conf->r1bio_pool)
1638 mempool_destroy(conf->r1bio_pool);
1639 kfree(conf->mirrors);
1640 kfree(conf->poolinfo);
1641 kfree(conf);
1642 mddev->private = NULL;
1643 return 0;
1644 }
1645
1646 static int raid1_resize(mddev_t *mddev, sector_t sectors)
1647 {
1648 /* no resync is happening, and there is enough space
1649 * on all devices, so we can resize.
1650 * We need to make sure resync covers any new space.
1651 * If the array is shrinking we should possibly wait until
1652 * any io in the removed space completes, but it hardly seems
1653 * worth it.
1654 */
1655 mddev->array_size = sectors>>1;
1656 set_capacity(mddev->gendisk, mddev->array_size << 1);
1657 mddev->changed = 1;
1658 if (mddev->array_size > mddev->size && mddev->recovery_cp == MaxSector) {
1659 mddev->recovery_cp = mddev->size << 1;
1660 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
1661 }
1662 mddev->size = mddev->array_size;
1663 mddev->resync_max_sectors = sectors;
1664 return 0;
1665 }
1666
1667 static int raid1_reshape(mddev_t *mddev, int raid_disks)
1668 {
1669 /* We need to:
1670 * 1/ resize the r1bio_pool
1671 * 2/ resize conf->mirrors
1672 *
1673 * We allocate a new r1bio_pool if we can.
1674 * Then raise a device barrier and wait until all IO stops.
1675 * Then resize conf->mirrors and swap in the new r1bio pool.
1676 *
1677 * At the same time, we "pack" the devices so that all the missing
1678 * devices have the higher raid_disk numbers.
1679 */
1680 mempool_t *newpool, *oldpool;
1681 struct pool_info *newpoolinfo;
1682 mirror_info_t *newmirrors;
1683 conf_t *conf = mddev_to_conf(mddev);
1684 int cnt;
1685
1686 int d, d2;
1687
1688 if (raid_disks < conf->raid_disks) {
1689 cnt=0;
1690 for (d= 0; d < conf->raid_disks; d++)
1691 if (conf->mirrors[d].rdev)
1692 cnt++;
1693 if (cnt > raid_disks)
1694 return -EBUSY;
1695 }
1696
1697 newpoolinfo = kmalloc(sizeof(*newpoolinfo), GFP_KERNEL);
1698 if (!newpoolinfo)
1699 return -ENOMEM;
1700 newpoolinfo->mddev = mddev;
1701 newpoolinfo->raid_disks = raid_disks;
1702
1703 newpool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc,
1704 r1bio_pool_free, newpoolinfo);
1705 if (!newpool) {
1706 kfree(newpoolinfo);
1707 return -ENOMEM;
1708 }
1709 newmirrors = kmalloc(sizeof(struct mirror_info) * raid_disks, GFP_KERNEL);
1710 if (!newmirrors) {
1711 kfree(newpoolinfo);
1712 mempool_destroy(newpool);
1713 return -ENOMEM;
1714 }
1715 memset(newmirrors, 0, sizeof(struct mirror_info)*raid_disks);
1716
1717 spin_lock_irq(&conf->resync_lock);
1718 conf->barrier++;
1719 wait_event_lock_irq(conf->wait_idle, !conf->nr_pending,
1720 conf->resync_lock, raid1_unplug(mddev->queue));
1721 spin_unlock_irq(&conf->resync_lock);
1722
1723 /* ok, everything is stopped */
1724 oldpool = conf->r1bio_pool;
1725 conf->r1bio_pool = newpool;
1726
1727 for (d=d2=0; d < conf->raid_disks; d++)
1728 if (conf->mirrors[d].rdev) {
1729 conf->mirrors[d].rdev->raid_disk = d2;
1730 newmirrors[d2++].rdev = conf->mirrors[d].rdev;
1731 }
1732 kfree(conf->mirrors);
1733 conf->mirrors = newmirrors;
1734 kfree(conf->poolinfo);
1735 conf->poolinfo = newpoolinfo;
1736
1737 mddev->degraded += (raid_disks - conf->raid_disks);
1738 conf->raid_disks = mddev->raid_disks = raid_disks;
1739
1740 conf->last_used = 0; /* just make sure it is in-range */
1741 spin_lock_irq(&conf->resync_lock);
1742 conf->barrier--;
1743 spin_unlock_irq(&conf->resync_lock);
1744 wake_up(&conf->wait_resume);
1745 wake_up(&conf->wait_idle);
1746
1747
1748 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
1749 md_wakeup_thread(mddev->thread);
1750
1751 mempool_destroy(oldpool);
1752 return 0;
1753 }
1754
1755 static void raid1_quiesce(mddev_t *mddev, int state)
1756 {
1757 conf_t *conf = mddev_to_conf(mddev);
1758
1759 switch(state) {
1760 case 1:
1761 spin_lock_irq(&conf->resync_lock);
1762 conf->barrier++;
1763 wait_event_lock_irq(conf->wait_idle, !conf->nr_pending,
1764 conf->resync_lock, raid1_unplug(mddev->queue));
1765 spin_unlock_irq(&conf->resync_lock);
1766 break;
1767 case 0:
1768 spin_lock_irq(&conf->resync_lock);
1769 conf->barrier--;
1770 spin_unlock_irq(&conf->resync_lock);
1771 wake_up(&conf->wait_resume);
1772 wake_up(&conf->wait_idle);
1773 break;
1774 }
1775 if (mddev->thread) {
1776 if (mddev->bitmap)
1777 mddev->thread->timeout = mddev->bitmap->daemon_sleep * HZ;
1778 else
1779 mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1780 md_wakeup_thread(mddev->thread);
1781 }
1782 }
1783
1784
1785 static mdk_personality_t raid1_personality =
1786 {
1787 .name = "raid1",
1788 .owner = THIS_MODULE,
1789 .make_request = make_request,
1790 .run = run,
1791 .stop = stop,
1792 .status = status,
1793 .error_handler = error,
1794 .hot_add_disk = raid1_add_disk,
1795 .hot_remove_disk= raid1_remove_disk,
1796 .spare_active = raid1_spare_active,
1797 .sync_request = sync_request,
1798 .resize = raid1_resize,
1799 .reshape = raid1_reshape,
1800 .quiesce = raid1_quiesce,
1801 };
1802
1803 static int __init raid_init(void)
1804 {
1805 return register_md_personality(RAID1, &raid1_personality);
1806 }
1807
1808 static void raid_exit(void)
1809 {
1810 unregister_md_personality(RAID1);
1811 }
1812
1813 module_init(raid_init);
1814 module_exit(raid_exit);
1815 MODULE_LICENSE("GPL");
1816 MODULE_ALIAS("md-personality-3"); /* RAID1 */
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