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md: change bitmap_unplug and others to void functions
[mirror_ubuntu-kernels.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 "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
51 static void unplug_slaves(mddev_t *mddev);
52
53 static void allow_barrier(conf_t *conf);
54 static void lower_barrier(conf_t *conf);
55
56 static void * r1bio_pool_alloc(gfp_t gfp_flags, void *data)
57 {
58 struct pool_info *pi = data;
59 r1bio_t *r1_bio;
60 int size = offsetof(r1bio_t, bios[pi->raid_disks]);
61
62 /* allocate a r1bio with room for raid_disks entries in the bios array */
63 r1_bio = kzalloc(size, gfp_flags);
64 if (!r1_bio)
65 unplug_slaves(pi->mddev);
66
67 return r1_bio;
68 }
69
70 static void r1bio_pool_free(void *r1_bio, void *data)
71 {
72 kfree(r1_bio);
73 }
74
75 #define RESYNC_BLOCK_SIZE (64*1024)
76 //#define RESYNC_BLOCK_SIZE PAGE_SIZE
77 #define RESYNC_SECTORS (RESYNC_BLOCK_SIZE >> 9)
78 #define RESYNC_PAGES ((RESYNC_BLOCK_SIZE + PAGE_SIZE-1) / PAGE_SIZE)
79 #define RESYNC_WINDOW (2048*1024)
80
81 static void * r1buf_pool_alloc(gfp_t gfp_flags, void *data)
82 {
83 struct pool_info *pi = data;
84 struct page *page;
85 r1bio_t *r1_bio;
86 struct bio *bio;
87 int i, j;
88
89 r1_bio = r1bio_pool_alloc(gfp_flags, pi);
90 if (!r1_bio) {
91 unplug_slaves(pi->mddev);
92 return NULL;
93 }
94
95 /*
96 * Allocate bios : 1 for reading, n-1 for writing
97 */
98 for (j = pi->raid_disks ; j-- ; ) {
99 bio = bio_alloc(gfp_flags, RESYNC_PAGES);
100 if (!bio)
101 goto out_free_bio;
102 r1_bio->bios[j] = bio;
103 }
104 /*
105 * Allocate RESYNC_PAGES data pages and attach them to
106 * the first bio.
107 * If this is a user-requested check/repair, allocate
108 * RESYNC_PAGES for each bio.
109 */
110 if (test_bit(MD_RECOVERY_REQUESTED, &pi->mddev->recovery))
111 j = pi->raid_disks;
112 else
113 j = 1;
114 while(j--) {
115 bio = r1_bio->bios[j];
116 for (i = 0; i < RESYNC_PAGES; i++) {
117 page = alloc_page(gfp_flags);
118 if (unlikely(!page))
119 goto out_free_pages;
120
121 bio->bi_io_vec[i].bv_page = page;
122 }
123 }
124 /* If not user-requests, copy the page pointers to all bios */
125 if (!test_bit(MD_RECOVERY_REQUESTED, &pi->mddev->recovery)) {
126 for (i=0; i<RESYNC_PAGES ; i++)
127 for (j=1; j<pi->raid_disks; j++)
128 r1_bio->bios[j]->bi_io_vec[i].bv_page =
129 r1_bio->bios[0]->bi_io_vec[i].bv_page;
130 }
131
132 r1_bio->master_bio = NULL;
133
134 return r1_bio;
135
136 out_free_pages:
137 for (i=0; i < RESYNC_PAGES ; i++)
138 for (j=0 ; j < pi->raid_disks; j++)
139 safe_put_page(r1_bio->bios[j]->bi_io_vec[i].bv_page);
140 j = -1;
141 out_free_bio:
142 while ( ++j < pi->raid_disks )
143 bio_put(r1_bio->bios[j]);
144 r1bio_pool_free(r1_bio, data);
145 return NULL;
146 }
147
148 static void r1buf_pool_free(void *__r1_bio, void *data)
149 {
150 struct pool_info *pi = data;
151 int i,j;
152 r1bio_t *r1bio = __r1_bio;
153
154 for (i = 0; i < RESYNC_PAGES; i++)
155 for (j = pi->raid_disks; j-- ;) {
156 if (j == 0 ||
157 r1bio->bios[j]->bi_io_vec[i].bv_page !=
158 r1bio->bios[0]->bi_io_vec[i].bv_page)
159 safe_put_page(r1bio->bios[j]->bi_io_vec[i].bv_page);
160 }
161 for (i=0 ; i < pi->raid_disks; i++)
162 bio_put(r1bio->bios[i]);
163
164 r1bio_pool_free(r1bio, data);
165 }
166
167 static void put_all_bios(conf_t *conf, r1bio_t *r1_bio)
168 {
169 int i;
170
171 for (i = 0; i < conf->raid_disks; i++) {
172 struct bio **bio = r1_bio->bios + i;
173 if (*bio && *bio != IO_BLOCKED)
174 bio_put(*bio);
175 *bio = NULL;
176 }
177 }
178
179 static void free_r1bio(r1bio_t *r1_bio)
180 {
181 conf_t *conf = mddev_to_conf(r1_bio->mddev);
182
183 /*
184 * Wake up any possible resync thread that waits for the device
185 * to go idle.
186 */
187 allow_barrier(conf);
188
189 put_all_bios(conf, r1_bio);
190 mempool_free(r1_bio, conf->r1bio_pool);
191 }
192
193 static void put_buf(r1bio_t *r1_bio)
194 {
195 conf_t *conf = mddev_to_conf(r1_bio->mddev);
196 int i;
197
198 for (i=0; i<conf->raid_disks; i++) {
199 struct bio *bio = r1_bio->bios[i];
200 if (bio->bi_end_io)
201 rdev_dec_pending(conf->mirrors[i].rdev, r1_bio->mddev);
202 }
203
204 mempool_free(r1_bio, conf->r1buf_pool);
205
206 lower_barrier(conf);
207 }
208
209 static void reschedule_retry(r1bio_t *r1_bio)
210 {
211 unsigned long flags;
212 mddev_t *mddev = r1_bio->mddev;
213 conf_t *conf = mddev_to_conf(mddev);
214
215 spin_lock_irqsave(&conf->device_lock, flags);
216 list_add(&r1_bio->retry_list, &conf->retry_list);
217 conf->nr_queued ++;
218 spin_unlock_irqrestore(&conf->device_lock, flags);
219
220 wake_up(&conf->wait_barrier);
221 md_wakeup_thread(mddev->thread);
222 }
223
224 /*
225 * raid_end_bio_io() is called when we have finished servicing a mirrored
226 * operation and are ready to return a success/failure code to the buffer
227 * cache layer.
228 */
229 static void raid_end_bio_io(r1bio_t *r1_bio)
230 {
231 struct bio *bio = r1_bio->master_bio;
232
233 /* if nobody has done the final endio yet, do it now */
234 if (!test_and_set_bit(R1BIO_Returned, &r1_bio->state)) {
235 PRINTK(KERN_DEBUG "raid1: sync end %s on sectors %llu-%llu\n",
236 (bio_data_dir(bio) == WRITE) ? "write" : "read",
237 (unsigned long long) bio->bi_sector,
238 (unsigned long long) bio->bi_sector +
239 (bio->bi_size >> 9) - 1);
240
241 bio_endio(bio, bio->bi_size,
242 test_bit(R1BIO_Uptodate, &r1_bio->state) ? 0 : -EIO);
243 }
244 free_r1bio(r1_bio);
245 }
246
247 /*
248 * Update disk head position estimator based on IRQ completion info.
249 */
250 static inline void update_head_pos(int disk, r1bio_t *r1_bio)
251 {
252 conf_t *conf = mddev_to_conf(r1_bio->mddev);
253
254 conf->mirrors[disk].head_position =
255 r1_bio->sector + (r1_bio->sectors);
256 }
257
258 static int raid1_end_read_request(struct bio *bio, unsigned int bytes_done, int error)
259 {
260 int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
261 r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private);
262 int mirror;
263 conf_t *conf = mddev_to_conf(r1_bio->mddev);
264
265 if (bio->bi_size)
266 return 1;
267
268 mirror = r1_bio->read_disk;
269 /*
270 * this branch is our 'one mirror IO has finished' event handler:
271 */
272 update_head_pos(mirror, r1_bio);
273
274 if (uptodate)
275 set_bit(R1BIO_Uptodate, &r1_bio->state);
276 else {
277 /* If all other devices have failed, we want to return
278 * the error upwards rather than fail the last device.
279 * Here we redefine "uptodate" to mean "Don't want to retry"
280 */
281 unsigned long flags;
282 spin_lock_irqsave(&conf->device_lock, flags);
283 if (r1_bio->mddev->degraded == conf->raid_disks ||
284 (r1_bio->mddev->degraded == conf->raid_disks-1 &&
285 !test_bit(Faulty, &conf->mirrors[mirror].rdev->flags)))
286 uptodate = 1;
287 spin_unlock_irqrestore(&conf->device_lock, flags);
288 }
289
290 if (uptodate)
291 raid_end_bio_io(r1_bio);
292 else {
293 /*
294 * oops, read error:
295 */
296 char b[BDEVNAME_SIZE];
297 if (printk_ratelimit())
298 printk(KERN_ERR "raid1: %s: rescheduling sector %llu\n",
299 bdevname(conf->mirrors[mirror].rdev->bdev,b), (unsigned long long)r1_bio->sector);
300 reschedule_retry(r1_bio);
301 }
302
303 rdev_dec_pending(conf->mirrors[mirror].rdev, conf->mddev);
304 return 0;
305 }
306
307 static int raid1_end_write_request(struct bio *bio, unsigned int bytes_done, int error)
308 {
309 int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
310 r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private);
311 int mirror, behind = test_bit(R1BIO_BehindIO, &r1_bio->state);
312 conf_t *conf = mddev_to_conf(r1_bio->mddev);
313 struct bio *to_put = NULL;
314
315 if (bio->bi_size)
316 return 1;
317
318 for (mirror = 0; mirror < conf->raid_disks; mirror++)
319 if (r1_bio->bios[mirror] == bio)
320 break;
321
322 if (error == -EOPNOTSUPP && test_bit(R1BIO_Barrier, &r1_bio->state)) {
323 set_bit(BarriersNotsupp, &conf->mirrors[mirror].rdev->flags);
324 set_bit(R1BIO_BarrierRetry, &r1_bio->state);
325 r1_bio->mddev->barriers_work = 0;
326 /* Don't rdev_dec_pending in this branch - keep it for the retry */
327 } else {
328 /*
329 * this branch is our 'one mirror IO has finished' event handler:
330 */
331 r1_bio->bios[mirror] = NULL;
332 to_put = bio;
333 if (!uptodate) {
334 md_error(r1_bio->mddev, conf->mirrors[mirror].rdev);
335 /* an I/O failed, we can't clear the bitmap */
336 set_bit(R1BIO_Degraded, &r1_bio->state);
337 } else
338 /*
339 * Set R1BIO_Uptodate in our master bio, so that
340 * we will return a good error code for to the higher
341 * levels even if IO on some other mirrored buffer fails.
342 *
343 * The 'master' represents the composite IO operation to
344 * user-side. So if something waits for IO, then it will
345 * wait for the 'master' bio.
346 */
347 set_bit(R1BIO_Uptodate, &r1_bio->state);
348
349 update_head_pos(mirror, r1_bio);
350
351 if (behind) {
352 if (test_bit(WriteMostly, &conf->mirrors[mirror].rdev->flags))
353 atomic_dec(&r1_bio->behind_remaining);
354
355 /* In behind mode, we ACK the master bio once the I/O has safely
356 * reached all non-writemostly disks. Setting the Returned bit
357 * ensures that this gets done only once -- we don't ever want to
358 * return -EIO here, instead we'll wait */
359
360 if (atomic_read(&r1_bio->behind_remaining) >= (atomic_read(&r1_bio->remaining)-1) &&
361 test_bit(R1BIO_Uptodate, &r1_bio->state)) {
362 /* Maybe we can return now */
363 if (!test_and_set_bit(R1BIO_Returned, &r1_bio->state)) {
364 struct bio *mbio = r1_bio->master_bio;
365 PRINTK(KERN_DEBUG "raid1: behind end write sectors %llu-%llu\n",
366 (unsigned long long) mbio->bi_sector,
367 (unsigned long long) mbio->bi_sector +
368 (mbio->bi_size >> 9) - 1);
369 bio_endio(mbio, mbio->bi_size, 0);
370 }
371 }
372 }
373 rdev_dec_pending(conf->mirrors[mirror].rdev, conf->mddev);
374 }
375 /*
376 *
377 * Let's see if all mirrored write operations have finished
378 * already.
379 */
380 if (atomic_dec_and_test(&r1_bio->remaining)) {
381 if (test_bit(R1BIO_BarrierRetry, &r1_bio->state))
382 reschedule_retry(r1_bio);
383 else {
384 /* it really is the end of this request */
385 if (test_bit(R1BIO_BehindIO, &r1_bio->state)) {
386 /* free extra copy of the data pages */
387 int i = bio->bi_vcnt;
388 while (i--)
389 safe_put_page(bio->bi_io_vec[i].bv_page);
390 }
391 /* clear the bitmap if all writes complete successfully */
392 bitmap_endwrite(r1_bio->mddev->bitmap, r1_bio->sector,
393 r1_bio->sectors,
394 !test_bit(R1BIO_Degraded, &r1_bio->state),
395 behind);
396 md_write_end(r1_bio->mddev);
397 raid_end_bio_io(r1_bio);
398 }
399 }
400
401 if (to_put)
402 bio_put(to_put);
403
404 return 0;
405 }
406
407
408 /*
409 * This routine returns the disk from which the requested read should
410 * be done. There is a per-array 'next expected sequential IO' sector
411 * number - if this matches on the next IO then we use the last disk.
412 * There is also a per-disk 'last know head position' sector that is
413 * maintained from IRQ contexts, both the normal and the resync IO
414 * completion handlers update this position correctly. If there is no
415 * perfect sequential match then we pick the disk whose head is closest.
416 *
417 * If there are 2 mirrors in the same 2 devices, performance degrades
418 * because position is mirror, not device based.
419 *
420 * The rdev for the device selected will have nr_pending incremented.
421 */
422 static int read_balance(conf_t *conf, r1bio_t *r1_bio)
423 {
424 const unsigned long this_sector = r1_bio->sector;
425 int new_disk = conf->last_used, disk = new_disk;
426 int wonly_disk = -1;
427 const int sectors = r1_bio->sectors;
428 sector_t new_distance, current_distance;
429 mdk_rdev_t *rdev;
430
431 rcu_read_lock();
432 /*
433 * Check if we can balance. We can balance on the whole
434 * device if no resync is going on, or below the resync window.
435 * We take the first readable disk when above the resync window.
436 */
437 retry:
438 if (conf->mddev->recovery_cp < MaxSector &&
439 (this_sector + sectors >= conf->next_resync)) {
440 /* Choose the first operation device, for consistancy */
441 new_disk = 0;
442
443 for (rdev = rcu_dereference(conf->mirrors[new_disk].rdev);
444 r1_bio->bios[new_disk] == IO_BLOCKED ||
445 !rdev || !test_bit(In_sync, &rdev->flags)
446 || test_bit(WriteMostly, &rdev->flags);
447 rdev = rcu_dereference(conf->mirrors[++new_disk].rdev)) {
448
449 if (rdev && test_bit(In_sync, &rdev->flags) &&
450 r1_bio->bios[new_disk] != IO_BLOCKED)
451 wonly_disk = new_disk;
452
453 if (new_disk == conf->raid_disks - 1) {
454 new_disk = wonly_disk;
455 break;
456 }
457 }
458 goto rb_out;
459 }
460
461
462 /* make sure the disk is operational */
463 for (rdev = rcu_dereference(conf->mirrors[new_disk].rdev);
464 r1_bio->bios[new_disk] == IO_BLOCKED ||
465 !rdev || !test_bit(In_sync, &rdev->flags) ||
466 test_bit(WriteMostly, &rdev->flags);
467 rdev = rcu_dereference(conf->mirrors[new_disk].rdev)) {
468
469 if (rdev && test_bit(In_sync, &rdev->flags) &&
470 r1_bio->bios[new_disk] != IO_BLOCKED)
471 wonly_disk = new_disk;
472
473 if (new_disk <= 0)
474 new_disk = conf->raid_disks;
475 new_disk--;
476 if (new_disk == disk) {
477 new_disk = wonly_disk;
478 break;
479 }
480 }
481
482 if (new_disk < 0)
483 goto rb_out;
484
485 disk = new_disk;
486 /* now disk == new_disk == starting point for search */
487
488 /*
489 * Don't change to another disk for sequential reads:
490 */
491 if (conf->next_seq_sect == this_sector)
492 goto rb_out;
493 if (this_sector == conf->mirrors[new_disk].head_position)
494 goto rb_out;
495
496 current_distance = abs(this_sector - conf->mirrors[disk].head_position);
497
498 /* Find the disk whose head is closest */
499
500 do {
501 if (disk <= 0)
502 disk = conf->raid_disks;
503 disk--;
504
505 rdev = rcu_dereference(conf->mirrors[disk].rdev);
506
507 if (!rdev || r1_bio->bios[disk] == IO_BLOCKED ||
508 !test_bit(In_sync, &rdev->flags) ||
509 test_bit(WriteMostly, &rdev->flags))
510 continue;
511
512 if (!atomic_read(&rdev->nr_pending)) {
513 new_disk = disk;
514 break;
515 }
516 new_distance = abs(this_sector - conf->mirrors[disk].head_position);
517 if (new_distance < current_distance) {
518 current_distance = new_distance;
519 new_disk = disk;
520 }
521 } while (disk != conf->last_used);
522
523 rb_out:
524
525
526 if (new_disk >= 0) {
527 rdev = rcu_dereference(conf->mirrors[new_disk].rdev);
528 if (!rdev)
529 goto retry;
530 atomic_inc(&rdev->nr_pending);
531 if (!test_bit(In_sync, &rdev->flags)) {
532 /* cannot risk returning a device that failed
533 * before we inc'ed nr_pending
534 */
535 rdev_dec_pending(rdev, conf->mddev);
536 goto retry;
537 }
538 conf->next_seq_sect = this_sector + sectors;
539 conf->last_used = new_disk;
540 }
541 rcu_read_unlock();
542
543 return new_disk;
544 }
545
546 static void unplug_slaves(mddev_t *mddev)
547 {
548 conf_t *conf = mddev_to_conf(mddev);
549 int i;
550
551 rcu_read_lock();
552 for (i=0; i<mddev->raid_disks; i++) {
553 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
554 if (rdev && !test_bit(Faulty, &rdev->flags) && atomic_read(&rdev->nr_pending)) {
555 request_queue_t *r_queue = bdev_get_queue(rdev->bdev);
556
557 atomic_inc(&rdev->nr_pending);
558 rcu_read_unlock();
559
560 if (r_queue->unplug_fn)
561 r_queue->unplug_fn(r_queue);
562
563 rdev_dec_pending(rdev, mddev);
564 rcu_read_lock();
565 }
566 }
567 rcu_read_unlock();
568 }
569
570 static void raid1_unplug(request_queue_t *q)
571 {
572 mddev_t *mddev = q->queuedata;
573
574 unplug_slaves(mddev);
575 md_wakeup_thread(mddev->thread);
576 }
577
578 static int raid1_issue_flush(request_queue_t *q, struct gendisk *disk,
579 sector_t *error_sector)
580 {
581 mddev_t *mddev = q->queuedata;
582 conf_t *conf = mddev_to_conf(mddev);
583 int i, ret = 0;
584
585 rcu_read_lock();
586 for (i=0; i<mddev->raid_disks && ret == 0; i++) {
587 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
588 if (rdev && !test_bit(Faulty, &rdev->flags)) {
589 struct block_device *bdev = rdev->bdev;
590 request_queue_t *r_queue = bdev_get_queue(bdev);
591
592 if (!r_queue->issue_flush_fn)
593 ret = -EOPNOTSUPP;
594 else {
595 atomic_inc(&rdev->nr_pending);
596 rcu_read_unlock();
597 ret = r_queue->issue_flush_fn(r_queue, bdev->bd_disk,
598 error_sector);
599 rdev_dec_pending(rdev, mddev);
600 rcu_read_lock();
601 }
602 }
603 }
604 rcu_read_unlock();
605 return ret;
606 }
607
608 static int raid1_congested(void *data, int bits)
609 {
610 mddev_t *mddev = data;
611 conf_t *conf = mddev_to_conf(mddev);
612 int i, ret = 0;
613
614 rcu_read_lock();
615 for (i = 0; i < mddev->raid_disks; i++) {
616 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
617 if (rdev && !test_bit(Faulty, &rdev->flags)) {
618 request_queue_t *q = bdev_get_queue(rdev->bdev);
619
620 /* Note the '|| 1' - when read_balance prefers
621 * non-congested targets, it can be removed
622 */
623 if ((bits & (1<<BDI_write_congested)) || 1)
624 ret |= bdi_congested(&q->backing_dev_info, bits);
625 else
626 ret &= bdi_congested(&q->backing_dev_info, bits);
627 }
628 }
629 rcu_read_unlock();
630 return ret;
631 }
632
633
634 /* Barriers....
635 * Sometimes we need to suspend IO while we do something else,
636 * either some resync/recovery, or reconfigure the array.
637 * To do this we raise a 'barrier'.
638 * The 'barrier' is a counter that can be raised multiple times
639 * to count how many activities are happening which preclude
640 * normal IO.
641 * We can only raise the barrier if there is no pending IO.
642 * i.e. if nr_pending == 0.
643 * We choose only to raise the barrier if no-one is waiting for the
644 * barrier to go down. This means that as soon as an IO request
645 * is ready, no other operations which require a barrier will start
646 * until the IO request has had a chance.
647 *
648 * So: regular IO calls 'wait_barrier'. When that returns there
649 * is no backgroup IO happening, It must arrange to call
650 * allow_barrier when it has finished its IO.
651 * backgroup IO calls must call raise_barrier. Once that returns
652 * there is no normal IO happeing. It must arrange to call
653 * lower_barrier when the particular background IO completes.
654 */
655 #define RESYNC_DEPTH 32
656
657 static void raise_barrier(conf_t *conf)
658 {
659 spin_lock_irq(&conf->resync_lock);
660
661 /* Wait until no block IO is waiting */
662 wait_event_lock_irq(conf->wait_barrier, !conf->nr_waiting,
663 conf->resync_lock,
664 raid1_unplug(conf->mddev->queue));
665
666 /* block any new IO from starting */
667 conf->barrier++;
668
669 /* No wait for all pending IO to complete */
670 wait_event_lock_irq(conf->wait_barrier,
671 !conf->nr_pending && conf->barrier < RESYNC_DEPTH,
672 conf->resync_lock,
673 raid1_unplug(conf->mddev->queue));
674
675 spin_unlock_irq(&conf->resync_lock);
676 }
677
678 static void lower_barrier(conf_t *conf)
679 {
680 unsigned long flags;
681 spin_lock_irqsave(&conf->resync_lock, flags);
682 conf->barrier--;
683 spin_unlock_irqrestore(&conf->resync_lock, flags);
684 wake_up(&conf->wait_barrier);
685 }
686
687 static void wait_barrier(conf_t *conf)
688 {
689 spin_lock_irq(&conf->resync_lock);
690 if (conf->barrier) {
691 conf->nr_waiting++;
692 wait_event_lock_irq(conf->wait_barrier, !conf->barrier,
693 conf->resync_lock,
694 raid1_unplug(conf->mddev->queue));
695 conf->nr_waiting--;
696 }
697 conf->nr_pending++;
698 spin_unlock_irq(&conf->resync_lock);
699 }
700
701 static void allow_barrier(conf_t *conf)
702 {
703 unsigned long flags;
704 spin_lock_irqsave(&conf->resync_lock, flags);
705 conf->nr_pending--;
706 spin_unlock_irqrestore(&conf->resync_lock, flags);
707 wake_up(&conf->wait_barrier);
708 }
709
710 static void freeze_array(conf_t *conf)
711 {
712 /* stop syncio and normal IO and wait for everything to
713 * go quite.
714 * We increment barrier and nr_waiting, and then
715 * wait until barrier+nr_pending match nr_queued+2
716 */
717 spin_lock_irq(&conf->resync_lock);
718 conf->barrier++;
719 conf->nr_waiting++;
720 wait_event_lock_irq(conf->wait_barrier,
721 conf->barrier+conf->nr_pending == conf->nr_queued+2,
722 conf->resync_lock,
723 raid1_unplug(conf->mddev->queue));
724 spin_unlock_irq(&conf->resync_lock);
725 }
726 static void unfreeze_array(conf_t *conf)
727 {
728 /* reverse the effect of the freeze */
729 spin_lock_irq(&conf->resync_lock);
730 conf->barrier--;
731 conf->nr_waiting--;
732 wake_up(&conf->wait_barrier);
733 spin_unlock_irq(&conf->resync_lock);
734 }
735
736
737 /* duplicate the data pages for behind I/O */
738 static struct page **alloc_behind_pages(struct bio *bio)
739 {
740 int i;
741 struct bio_vec *bvec;
742 struct page **pages = kzalloc(bio->bi_vcnt * sizeof(struct page *),
743 GFP_NOIO);
744 if (unlikely(!pages))
745 goto do_sync_io;
746
747 bio_for_each_segment(bvec, bio, i) {
748 pages[i] = alloc_page(GFP_NOIO);
749 if (unlikely(!pages[i]))
750 goto do_sync_io;
751 memcpy(kmap(pages[i]) + bvec->bv_offset,
752 kmap(bvec->bv_page) + bvec->bv_offset, bvec->bv_len);
753 kunmap(pages[i]);
754 kunmap(bvec->bv_page);
755 }
756
757 return pages;
758
759 do_sync_io:
760 if (pages)
761 for (i = 0; i < bio->bi_vcnt && pages[i]; i++)
762 put_page(pages[i]);
763 kfree(pages);
764 PRINTK("%dB behind alloc failed, doing sync I/O\n", bio->bi_size);
765 return NULL;
766 }
767
768 static int make_request(request_queue_t *q, struct bio * bio)
769 {
770 mddev_t *mddev = q->queuedata;
771 conf_t *conf = mddev_to_conf(mddev);
772 mirror_info_t *mirror;
773 r1bio_t *r1_bio;
774 struct bio *read_bio;
775 int i, targets = 0, disks;
776 mdk_rdev_t *rdev;
777 struct bitmap *bitmap = mddev->bitmap;
778 unsigned long flags;
779 struct bio_list bl;
780 struct page **behind_pages = NULL;
781 const int rw = bio_data_dir(bio);
782 const int do_sync = bio_sync(bio);
783 int do_barriers;
784
785 /*
786 * Register the new request and wait if the reconstruction
787 * thread has put up a bar for new requests.
788 * Continue immediately if no resync is active currently.
789 * We test barriers_work *after* md_write_start as md_write_start
790 * may cause the first superblock write, and that will check out
791 * if barriers work.
792 */
793
794 md_write_start(mddev, bio); /* wait on superblock update early */
795
796 if (unlikely(!mddev->barriers_work && bio_barrier(bio))) {
797 if (rw == WRITE)
798 md_write_end(mddev);
799 bio_endio(bio, bio->bi_size, -EOPNOTSUPP);
800 return 0;
801 }
802
803 wait_barrier(conf);
804
805 disk_stat_inc(mddev->gendisk, ios[rw]);
806 disk_stat_add(mddev->gendisk, sectors[rw], bio_sectors(bio));
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 if (rw == READ) {
822 /*
823 * read balancing logic:
824 */
825 int rdisk = read_balance(conf, r1_bio);
826
827 if (rdisk < 0) {
828 /* couldn't find anywhere to read from */
829 raid_end_bio_io(r1_bio);
830 return 0;
831 }
832 mirror = conf->mirrors + rdisk;
833
834 r1_bio->read_disk = rdisk;
835
836 read_bio = bio_clone(bio, GFP_NOIO);
837
838 r1_bio->bios[rdisk] = read_bio;
839
840 read_bio->bi_sector = r1_bio->sector + mirror->rdev->data_offset;
841 read_bio->bi_bdev = mirror->rdev->bdev;
842 read_bio->bi_end_io = raid1_end_read_request;
843 read_bio->bi_rw = READ | do_sync;
844 read_bio->bi_private = r1_bio;
845
846 generic_make_request(read_bio);
847 return 0;
848 }
849
850 /*
851 * WRITE:
852 */
853 /* first select target devices under spinlock and
854 * inc refcount on their rdev. Record them by setting
855 * bios[x] to bio
856 */
857 disks = conf->raid_disks;
858 #if 0
859 { static int first=1;
860 if (first) printk("First Write sector %llu disks %d\n",
861 (unsigned long long)r1_bio->sector, disks);
862 first = 0;
863 }
864 #endif
865 rcu_read_lock();
866 for (i = 0; i < disks; i++) {
867 if ((rdev=rcu_dereference(conf->mirrors[i].rdev)) != NULL &&
868 !test_bit(Faulty, &rdev->flags)) {
869 atomic_inc(&rdev->nr_pending);
870 if (test_bit(Faulty, &rdev->flags)) {
871 rdev_dec_pending(rdev, mddev);
872 r1_bio->bios[i] = NULL;
873 } else
874 r1_bio->bios[i] = bio;
875 targets++;
876 } else
877 r1_bio->bios[i] = NULL;
878 }
879 rcu_read_unlock();
880
881 BUG_ON(targets == 0); /* we never fail the last device */
882
883 if (targets < conf->raid_disks) {
884 /* array is degraded, we will not clear the bitmap
885 * on I/O completion (see raid1_end_write_request) */
886 set_bit(R1BIO_Degraded, &r1_bio->state);
887 }
888
889 /* do behind I/O ? */
890 if (bitmap &&
891 atomic_read(&bitmap->behind_writes) < bitmap->max_write_behind &&
892 (behind_pages = alloc_behind_pages(bio)) != NULL)
893 set_bit(R1BIO_BehindIO, &r1_bio->state);
894
895 atomic_set(&r1_bio->remaining, 0);
896 atomic_set(&r1_bio->behind_remaining, 0);
897
898 do_barriers = bio_barrier(bio);
899 if (do_barriers)
900 set_bit(R1BIO_Barrier, &r1_bio->state);
901
902 bio_list_init(&bl);
903 for (i = 0; i < disks; i++) {
904 struct bio *mbio;
905 if (!r1_bio->bios[i])
906 continue;
907
908 mbio = bio_clone(bio, GFP_NOIO);
909 r1_bio->bios[i] = mbio;
910
911 mbio->bi_sector = r1_bio->sector + conf->mirrors[i].rdev->data_offset;
912 mbio->bi_bdev = conf->mirrors[i].rdev->bdev;
913 mbio->bi_end_io = raid1_end_write_request;
914 mbio->bi_rw = WRITE | do_barriers | do_sync;
915 mbio->bi_private = r1_bio;
916
917 if (behind_pages) {
918 struct bio_vec *bvec;
919 int j;
920
921 /* Yes, I really want the '__' version so that
922 * we clear any unused pointer in the io_vec, rather
923 * than leave them unchanged. This is important
924 * because when we come to free the pages, we won't
925 * know the originial bi_idx, so we just free
926 * them all
927 */
928 __bio_for_each_segment(bvec, mbio, j, 0)
929 bvec->bv_page = behind_pages[j];
930 if (test_bit(WriteMostly, &conf->mirrors[i].rdev->flags))
931 atomic_inc(&r1_bio->behind_remaining);
932 }
933
934 atomic_inc(&r1_bio->remaining);
935
936 bio_list_add(&bl, mbio);
937 }
938 kfree(behind_pages); /* the behind pages are attached to the bios now */
939
940 bitmap_startwrite(bitmap, bio->bi_sector, r1_bio->sectors,
941 test_bit(R1BIO_BehindIO, &r1_bio->state));
942 spin_lock_irqsave(&conf->device_lock, flags);
943 bio_list_merge(&conf->pending_bio_list, &bl);
944 bio_list_init(&bl);
945
946 blk_plug_device(mddev->queue);
947 spin_unlock_irqrestore(&conf->device_lock, flags);
948
949 if (do_sync)
950 md_wakeup_thread(mddev->thread);
951 #if 0
952 while ((bio = bio_list_pop(&bl)) != NULL)
953 generic_make_request(bio);
954 #endif
955
956 return 0;
957 }
958
959 static void status(struct seq_file *seq, mddev_t *mddev)
960 {
961 conf_t *conf = mddev_to_conf(mddev);
962 int i;
963
964 seq_printf(seq, " [%d/%d] [", conf->raid_disks,
965 conf->raid_disks - mddev->degraded);
966 rcu_read_lock();
967 for (i = 0; i < conf->raid_disks; i++) {
968 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
969 seq_printf(seq, "%s",
970 rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_");
971 }
972 rcu_read_unlock();
973 seq_printf(seq, "]");
974 }
975
976
977 static void error(mddev_t *mddev, mdk_rdev_t *rdev)
978 {
979 char b[BDEVNAME_SIZE];
980 conf_t *conf = mddev_to_conf(mddev);
981
982 /*
983 * If it is not operational, then we have already marked it as dead
984 * else if it is the last working disks, ignore the error, let the
985 * next level up know.
986 * else mark the drive as failed
987 */
988 if (test_bit(In_sync, &rdev->flags)
989 && (conf->raid_disks - mddev->degraded) == 1)
990 /*
991 * Don't fail the drive, act as though we were just a
992 * normal single drive
993 */
994 return;
995 if (test_and_clear_bit(In_sync, &rdev->flags)) {
996 unsigned long flags;
997 spin_lock_irqsave(&conf->device_lock, flags);
998 mddev->degraded++;
999 set_bit(Faulty, &rdev->flags);
1000 spin_unlock_irqrestore(&conf->device_lock, flags);
1001 /*
1002 * if recovery is running, make sure it aborts.
1003 */
1004 set_bit(MD_RECOVERY_ERR, &mddev->recovery);
1005 } else
1006 set_bit(Faulty, &rdev->flags);
1007 set_bit(MD_CHANGE_DEVS, &mddev->flags);
1008 printk(KERN_ALERT "raid1: Disk failure on %s, disabling device. \n"
1009 " Operation continuing on %d devices\n",
1010 bdevname(rdev->bdev,b), conf->raid_disks - mddev->degraded);
1011 }
1012
1013 static void print_conf(conf_t *conf)
1014 {
1015 int i;
1016
1017 printk("RAID1 conf printout:\n");
1018 if (!conf) {
1019 printk("(!conf)\n");
1020 return;
1021 }
1022 printk(" --- wd:%d rd:%d\n", conf->raid_disks - conf->mddev->degraded,
1023 conf->raid_disks);
1024
1025 rcu_read_lock();
1026 for (i = 0; i < conf->raid_disks; i++) {
1027 char b[BDEVNAME_SIZE];
1028 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
1029 if (rdev)
1030 printk(" disk %d, wo:%d, o:%d, dev:%s\n",
1031 i, !test_bit(In_sync, &rdev->flags),
1032 !test_bit(Faulty, &rdev->flags),
1033 bdevname(rdev->bdev,b));
1034 }
1035 rcu_read_unlock();
1036 }
1037
1038 static void close_sync(conf_t *conf)
1039 {
1040 wait_barrier(conf);
1041 allow_barrier(conf);
1042
1043 mempool_destroy(conf->r1buf_pool);
1044 conf->r1buf_pool = NULL;
1045 }
1046
1047 static int raid1_spare_active(mddev_t *mddev)
1048 {
1049 int i;
1050 conf_t *conf = mddev->private;
1051
1052 /*
1053 * Find all failed disks within the RAID1 configuration
1054 * and mark them readable.
1055 * Called under mddev lock, so rcu protection not needed.
1056 */
1057 for (i = 0; i < conf->raid_disks; i++) {
1058 mdk_rdev_t *rdev = conf->mirrors[i].rdev;
1059 if (rdev
1060 && !test_bit(Faulty, &rdev->flags)
1061 && !test_and_set_bit(In_sync, &rdev->flags)) {
1062 unsigned long flags;
1063 spin_lock_irqsave(&conf->device_lock, flags);
1064 mddev->degraded--;
1065 spin_unlock_irqrestore(&conf->device_lock, flags);
1066 }
1067 }
1068
1069 print_conf(conf);
1070 return 0;
1071 }
1072
1073
1074 static int raid1_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
1075 {
1076 conf_t *conf = mddev->private;
1077 int found = 0;
1078 int mirror = 0;
1079 mirror_info_t *p;
1080
1081 for (mirror=0; mirror < mddev->raid_disks; mirror++)
1082 if ( !(p=conf->mirrors+mirror)->rdev) {
1083
1084 blk_queue_stack_limits(mddev->queue,
1085 rdev->bdev->bd_disk->queue);
1086 /* as we don't honour merge_bvec_fn, we must never risk
1087 * violating it, so limit ->max_sector to one PAGE, as
1088 * a one page request is never in violation.
1089 */
1090 if (rdev->bdev->bd_disk->queue->merge_bvec_fn &&
1091 mddev->queue->max_sectors > (PAGE_SIZE>>9))
1092 blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9);
1093
1094 p->head_position = 0;
1095 rdev->raid_disk = mirror;
1096 found = 1;
1097 /* As all devices are equivalent, we don't need a full recovery
1098 * if this was recently any drive of the array
1099 */
1100 if (rdev->saved_raid_disk < 0)
1101 conf->fullsync = 1;
1102 rcu_assign_pointer(p->rdev, rdev);
1103 break;
1104 }
1105
1106 print_conf(conf);
1107 return found;
1108 }
1109
1110 static int raid1_remove_disk(mddev_t *mddev, int number)
1111 {
1112 conf_t *conf = mddev->private;
1113 int err = 0;
1114 mdk_rdev_t *rdev;
1115 mirror_info_t *p = conf->mirrors+ number;
1116
1117 print_conf(conf);
1118 rdev = p->rdev;
1119 if (rdev) {
1120 if (test_bit(In_sync, &rdev->flags) ||
1121 atomic_read(&rdev->nr_pending)) {
1122 err = -EBUSY;
1123 goto abort;
1124 }
1125 p->rdev = NULL;
1126 synchronize_rcu();
1127 if (atomic_read(&rdev->nr_pending)) {
1128 /* lost the race, try later */
1129 err = -EBUSY;
1130 p->rdev = rdev;
1131 }
1132 }
1133 abort:
1134
1135 print_conf(conf);
1136 return err;
1137 }
1138
1139
1140 static int end_sync_read(struct bio *bio, unsigned int bytes_done, int error)
1141 {
1142 r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private);
1143 int i;
1144
1145 if (bio->bi_size)
1146 return 1;
1147
1148 for (i=r1_bio->mddev->raid_disks; i--; )
1149 if (r1_bio->bios[i] == bio)
1150 break;
1151 BUG_ON(i < 0);
1152 update_head_pos(i, r1_bio);
1153 /*
1154 * we have read a block, now it needs to be re-written,
1155 * or re-read if the read failed.
1156 * We don't do much here, just schedule handling by raid1d
1157 */
1158 if (test_bit(BIO_UPTODATE, &bio->bi_flags))
1159 set_bit(R1BIO_Uptodate, &r1_bio->state);
1160
1161 if (atomic_dec_and_test(&r1_bio->remaining))
1162 reschedule_retry(r1_bio);
1163 return 0;
1164 }
1165
1166 static int end_sync_write(struct bio *bio, unsigned int bytes_done, int error)
1167 {
1168 int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
1169 r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private);
1170 mddev_t *mddev = r1_bio->mddev;
1171 conf_t *conf = mddev_to_conf(mddev);
1172 int i;
1173 int mirror=0;
1174
1175 if (bio->bi_size)
1176 return 1;
1177
1178 for (i = 0; i < conf->raid_disks; i++)
1179 if (r1_bio->bios[i] == bio) {
1180 mirror = i;
1181 break;
1182 }
1183 if (!uptodate) {
1184 int sync_blocks = 0;
1185 sector_t s = r1_bio->sector;
1186 long sectors_to_go = r1_bio->sectors;
1187 /* make sure these bits doesn't get cleared. */
1188 do {
1189 bitmap_end_sync(mddev->bitmap, s,
1190 &sync_blocks, 1);
1191 s += sync_blocks;
1192 sectors_to_go -= sync_blocks;
1193 } while (sectors_to_go > 0);
1194 md_error(mddev, conf->mirrors[mirror].rdev);
1195 }
1196
1197 update_head_pos(mirror, r1_bio);
1198
1199 if (atomic_dec_and_test(&r1_bio->remaining)) {
1200 md_done_sync(mddev, r1_bio->sectors, uptodate);
1201 put_buf(r1_bio);
1202 }
1203 return 0;
1204 }
1205
1206 static void sync_request_write(mddev_t *mddev, r1bio_t *r1_bio)
1207 {
1208 conf_t *conf = mddev_to_conf(mddev);
1209 int i;
1210 int disks = conf->raid_disks;
1211 struct bio *bio, *wbio;
1212
1213 bio = r1_bio->bios[r1_bio->read_disk];
1214
1215
1216 if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
1217 /* We have read all readable devices. If we haven't
1218 * got the block, then there is no hope left.
1219 * If we have, then we want to do a comparison
1220 * and skip the write if everything is the same.
1221 * If any blocks failed to read, then we need to
1222 * attempt an over-write
1223 */
1224 int primary;
1225 if (!test_bit(R1BIO_Uptodate, &r1_bio->state)) {
1226 for (i=0; i<mddev->raid_disks; i++)
1227 if (r1_bio->bios[i]->bi_end_io == end_sync_read)
1228 md_error(mddev, conf->mirrors[i].rdev);
1229
1230 md_done_sync(mddev, r1_bio->sectors, 1);
1231 put_buf(r1_bio);
1232 return;
1233 }
1234 for (primary=0; primary<mddev->raid_disks; primary++)
1235 if (r1_bio->bios[primary]->bi_end_io == end_sync_read &&
1236 test_bit(BIO_UPTODATE, &r1_bio->bios[primary]->bi_flags)) {
1237 r1_bio->bios[primary]->bi_end_io = NULL;
1238 rdev_dec_pending(conf->mirrors[primary].rdev, mddev);
1239 break;
1240 }
1241 r1_bio->read_disk = primary;
1242 for (i=0; i<mddev->raid_disks; i++)
1243 if (r1_bio->bios[i]->bi_end_io == end_sync_read) {
1244 int j;
1245 int vcnt = r1_bio->sectors >> (PAGE_SHIFT- 9);
1246 struct bio *pbio = r1_bio->bios[primary];
1247 struct bio *sbio = r1_bio->bios[i];
1248
1249 if (test_bit(BIO_UPTODATE, &sbio->bi_flags)) {
1250 for (j = vcnt; j-- ; ) {
1251 struct page *p, *s;
1252 p = pbio->bi_io_vec[j].bv_page;
1253 s = sbio->bi_io_vec[j].bv_page;
1254 if (memcmp(page_address(p),
1255 page_address(s),
1256 PAGE_SIZE))
1257 break;
1258 }
1259 } else
1260 j = 0;
1261 if (j >= 0)
1262 mddev->resync_mismatches += r1_bio->sectors;
1263 if (j < 0 || test_bit(MD_RECOVERY_CHECK, &mddev->recovery)) {
1264 sbio->bi_end_io = NULL;
1265 rdev_dec_pending(conf->mirrors[i].rdev, mddev);
1266 } else {
1267 /* fixup the bio for reuse */
1268 sbio->bi_vcnt = vcnt;
1269 sbio->bi_size = r1_bio->sectors << 9;
1270 sbio->bi_idx = 0;
1271 sbio->bi_phys_segments = 0;
1272 sbio->bi_hw_segments = 0;
1273 sbio->bi_hw_front_size = 0;
1274 sbio->bi_hw_back_size = 0;
1275 sbio->bi_flags &= ~(BIO_POOL_MASK - 1);
1276 sbio->bi_flags |= 1 << BIO_UPTODATE;
1277 sbio->bi_next = NULL;
1278 sbio->bi_sector = r1_bio->sector +
1279 conf->mirrors[i].rdev->data_offset;
1280 sbio->bi_bdev = conf->mirrors[i].rdev->bdev;
1281 for (j = 0; j < vcnt ; j++)
1282 memcpy(page_address(sbio->bi_io_vec[j].bv_page),
1283 page_address(pbio->bi_io_vec[j].bv_page),
1284 PAGE_SIZE);
1285
1286 }
1287 }
1288 }
1289 if (!test_bit(R1BIO_Uptodate, &r1_bio->state)) {
1290 /* ouch - failed to read all of that.
1291 * Try some synchronous reads of other devices to get
1292 * good data, much like with normal read errors. Only
1293 * read into the pages we already have so we don't
1294 * need to re-issue the read request.
1295 * We don't need to freeze the array, because being in an
1296 * active sync request, there is no normal IO, and
1297 * no overlapping syncs.
1298 */
1299 sector_t sect = r1_bio->sector;
1300 int sectors = r1_bio->sectors;
1301 int idx = 0;
1302
1303 while(sectors) {
1304 int s = sectors;
1305 int d = r1_bio->read_disk;
1306 int success = 0;
1307 mdk_rdev_t *rdev;
1308
1309 if (s > (PAGE_SIZE>>9))
1310 s = PAGE_SIZE >> 9;
1311 do {
1312 if (r1_bio->bios[d]->bi_end_io == end_sync_read) {
1313 /* No rcu protection needed here devices
1314 * can only be removed when no resync is
1315 * active, and resync is currently active
1316 */
1317 rdev = conf->mirrors[d].rdev;
1318 if (sync_page_io(rdev->bdev,
1319 sect + rdev->data_offset,
1320 s<<9,
1321 bio->bi_io_vec[idx].bv_page,
1322 READ)) {
1323 success = 1;
1324 break;
1325 }
1326 }
1327 d++;
1328 if (d == conf->raid_disks)
1329 d = 0;
1330 } while (!success && d != r1_bio->read_disk);
1331
1332 if (success) {
1333 int start = d;
1334 /* write it back and re-read */
1335 set_bit(R1BIO_Uptodate, &r1_bio->state);
1336 while (d != r1_bio->read_disk) {
1337 if (d == 0)
1338 d = conf->raid_disks;
1339 d--;
1340 if (r1_bio->bios[d]->bi_end_io != end_sync_read)
1341 continue;
1342 rdev = conf->mirrors[d].rdev;
1343 atomic_add(s, &rdev->corrected_errors);
1344 if (sync_page_io(rdev->bdev,
1345 sect + rdev->data_offset,
1346 s<<9,
1347 bio->bi_io_vec[idx].bv_page,
1348 WRITE) == 0)
1349 md_error(mddev, rdev);
1350 }
1351 d = start;
1352 while (d != r1_bio->read_disk) {
1353 if (d == 0)
1354 d = conf->raid_disks;
1355 d--;
1356 if (r1_bio->bios[d]->bi_end_io != end_sync_read)
1357 continue;
1358 rdev = conf->mirrors[d].rdev;
1359 if (sync_page_io(rdev->bdev,
1360 sect + rdev->data_offset,
1361 s<<9,
1362 bio->bi_io_vec[idx].bv_page,
1363 READ) == 0)
1364 md_error(mddev, rdev);
1365 }
1366 } else {
1367 char b[BDEVNAME_SIZE];
1368 /* Cannot read from anywhere, array is toast */
1369 md_error(mddev, conf->mirrors[r1_bio->read_disk].rdev);
1370 printk(KERN_ALERT "raid1: %s: unrecoverable I/O read error"
1371 " for block %llu\n",
1372 bdevname(bio->bi_bdev,b),
1373 (unsigned long long)r1_bio->sector);
1374 md_done_sync(mddev, r1_bio->sectors, 0);
1375 put_buf(r1_bio);
1376 return;
1377 }
1378 sectors -= s;
1379 sect += s;
1380 idx ++;
1381 }
1382 }
1383
1384 /*
1385 * schedule writes
1386 */
1387 atomic_set(&r1_bio->remaining, 1);
1388 for (i = 0; i < disks ; i++) {
1389 wbio = r1_bio->bios[i];
1390 if (wbio->bi_end_io == NULL ||
1391 (wbio->bi_end_io == end_sync_read &&
1392 (i == r1_bio->read_disk ||
1393 !test_bit(MD_RECOVERY_SYNC, &mddev->recovery))))
1394 continue;
1395
1396 wbio->bi_rw = WRITE;
1397 wbio->bi_end_io = end_sync_write;
1398 atomic_inc(&r1_bio->remaining);
1399 md_sync_acct(conf->mirrors[i].rdev->bdev, wbio->bi_size >> 9);
1400
1401 generic_make_request(wbio);
1402 }
1403
1404 if (atomic_dec_and_test(&r1_bio->remaining)) {
1405 /* if we're here, all write(s) have completed, so clean up */
1406 md_done_sync(mddev, r1_bio->sectors, 1);
1407 put_buf(r1_bio);
1408 }
1409 }
1410
1411 /*
1412 * This is a kernel thread which:
1413 *
1414 * 1. Retries failed read operations on working mirrors.
1415 * 2. Updates the raid superblock when problems encounter.
1416 * 3. Performs writes following reads for array syncronising.
1417 */
1418
1419 static void fix_read_error(conf_t *conf, int read_disk,
1420 sector_t sect, int sectors)
1421 {
1422 mddev_t *mddev = conf->mddev;
1423 while(sectors) {
1424 int s = sectors;
1425 int d = read_disk;
1426 int success = 0;
1427 int start;
1428 mdk_rdev_t *rdev;
1429
1430 if (s > (PAGE_SIZE>>9))
1431 s = PAGE_SIZE >> 9;
1432
1433 do {
1434 /* Note: no rcu protection needed here
1435 * as this is synchronous in the raid1d thread
1436 * which is the thread that might remove
1437 * a device. If raid1d ever becomes multi-threaded....
1438 */
1439 rdev = conf->mirrors[d].rdev;
1440 if (rdev &&
1441 test_bit(In_sync, &rdev->flags) &&
1442 sync_page_io(rdev->bdev,
1443 sect + rdev->data_offset,
1444 s<<9,
1445 conf->tmppage, READ))
1446 success = 1;
1447 else {
1448 d++;
1449 if (d == conf->raid_disks)
1450 d = 0;
1451 }
1452 } while (!success && d != read_disk);
1453
1454 if (!success) {
1455 /* Cannot read from anywhere -- bye bye array */
1456 md_error(mddev, conf->mirrors[read_disk].rdev);
1457 break;
1458 }
1459 /* write it back and re-read */
1460 start = d;
1461 while (d != read_disk) {
1462 if (d==0)
1463 d = conf->raid_disks;
1464 d--;
1465 rdev = conf->mirrors[d].rdev;
1466 if (rdev &&
1467 test_bit(In_sync, &rdev->flags)) {
1468 if (sync_page_io(rdev->bdev,
1469 sect + rdev->data_offset,
1470 s<<9, conf->tmppage, WRITE)
1471 == 0)
1472 /* Well, this device is dead */
1473 md_error(mddev, rdev);
1474 }
1475 }
1476 d = start;
1477 while (d != read_disk) {
1478 char b[BDEVNAME_SIZE];
1479 if (d==0)
1480 d = conf->raid_disks;
1481 d--;
1482 rdev = conf->mirrors[d].rdev;
1483 if (rdev &&
1484 test_bit(In_sync, &rdev->flags)) {
1485 if (sync_page_io(rdev->bdev,
1486 sect + rdev->data_offset,
1487 s<<9, conf->tmppage, READ)
1488 == 0)
1489 /* Well, this device is dead */
1490 md_error(mddev, rdev);
1491 else {
1492 atomic_add(s, &rdev->corrected_errors);
1493 printk(KERN_INFO
1494 "raid1:%s: read error corrected "
1495 "(%d sectors at %llu on %s)\n",
1496 mdname(mddev), s,
1497 (unsigned long long)(sect +
1498 rdev->data_offset),
1499 bdevname(rdev->bdev, b));
1500 }
1501 }
1502 }
1503 sectors -= s;
1504 sect += s;
1505 }
1506 }
1507
1508 static void raid1d(mddev_t *mddev)
1509 {
1510 r1bio_t *r1_bio;
1511 struct bio *bio;
1512 unsigned long flags;
1513 conf_t *conf = mddev_to_conf(mddev);
1514 struct list_head *head = &conf->retry_list;
1515 int unplug=0;
1516 mdk_rdev_t *rdev;
1517
1518 md_check_recovery(mddev);
1519
1520 for (;;) {
1521 char b[BDEVNAME_SIZE];
1522 spin_lock_irqsave(&conf->device_lock, flags);
1523
1524 if (conf->pending_bio_list.head) {
1525 bio = bio_list_get(&conf->pending_bio_list);
1526 blk_remove_plug(mddev->queue);
1527 spin_unlock_irqrestore(&conf->device_lock, flags);
1528 /* flush any pending bitmap writes to disk before proceeding w/ I/O */
1529 bitmap_unplug(mddev->bitmap);
1530
1531 while (bio) { /* submit pending writes */
1532 struct bio *next = bio->bi_next;
1533 bio->bi_next = NULL;
1534 generic_make_request(bio);
1535 bio = next;
1536 }
1537 unplug = 1;
1538
1539 continue;
1540 }
1541
1542 if (list_empty(head))
1543 break;
1544 r1_bio = list_entry(head->prev, r1bio_t, retry_list);
1545 list_del(head->prev);
1546 conf->nr_queued--;
1547 spin_unlock_irqrestore(&conf->device_lock, flags);
1548
1549 mddev = r1_bio->mddev;
1550 conf = mddev_to_conf(mddev);
1551 if (test_bit(R1BIO_IsSync, &r1_bio->state)) {
1552 sync_request_write(mddev, r1_bio);
1553 unplug = 1;
1554 } else if (test_bit(R1BIO_BarrierRetry, &r1_bio->state)) {
1555 /* some requests in the r1bio were BIO_RW_BARRIER
1556 * requests which failed with -EOPNOTSUPP. Hohumm..
1557 * Better resubmit without the barrier.
1558 * We know which devices to resubmit for, because
1559 * all others have had their bios[] entry cleared.
1560 * We already have a nr_pending reference on these rdevs.
1561 */
1562 int i;
1563 const int do_sync = bio_sync(r1_bio->master_bio);
1564 clear_bit(R1BIO_BarrierRetry, &r1_bio->state);
1565 clear_bit(R1BIO_Barrier, &r1_bio->state);
1566 for (i=0; i < conf->raid_disks; i++)
1567 if (r1_bio->bios[i])
1568 atomic_inc(&r1_bio->remaining);
1569 for (i=0; i < conf->raid_disks; i++)
1570 if (r1_bio->bios[i]) {
1571 struct bio_vec *bvec;
1572 int j;
1573
1574 bio = bio_clone(r1_bio->master_bio, GFP_NOIO);
1575 /* copy pages from the failed bio, as
1576 * this might be a write-behind device */
1577 __bio_for_each_segment(bvec, bio, j, 0)
1578 bvec->bv_page = bio_iovec_idx(r1_bio->bios[i], j)->bv_page;
1579 bio_put(r1_bio->bios[i]);
1580 bio->bi_sector = r1_bio->sector +
1581 conf->mirrors[i].rdev->data_offset;
1582 bio->bi_bdev = conf->mirrors[i].rdev->bdev;
1583 bio->bi_end_io = raid1_end_write_request;
1584 bio->bi_rw = WRITE | do_sync;
1585 bio->bi_private = r1_bio;
1586 r1_bio->bios[i] = bio;
1587 generic_make_request(bio);
1588 }
1589 } else {
1590 int disk;
1591
1592 /* we got a read error. Maybe the drive is bad. Maybe just
1593 * the block and we can fix it.
1594 * We freeze all other IO, and try reading the block from
1595 * other devices. When we find one, we re-write
1596 * and check it that fixes the read error.
1597 * This is all done synchronously while the array is
1598 * frozen
1599 */
1600 if (mddev->ro == 0) {
1601 freeze_array(conf);
1602 fix_read_error(conf, r1_bio->read_disk,
1603 r1_bio->sector,
1604 r1_bio->sectors);
1605 unfreeze_array(conf);
1606 }
1607
1608 bio = r1_bio->bios[r1_bio->read_disk];
1609 if ((disk=read_balance(conf, r1_bio)) == -1) {
1610 printk(KERN_ALERT "raid1: %s: unrecoverable I/O"
1611 " read error for block %llu\n",
1612 bdevname(bio->bi_bdev,b),
1613 (unsigned long long)r1_bio->sector);
1614 raid_end_bio_io(r1_bio);
1615 } else {
1616 const int do_sync = bio_sync(r1_bio->master_bio);
1617 r1_bio->bios[r1_bio->read_disk] =
1618 mddev->ro ? IO_BLOCKED : NULL;
1619 r1_bio->read_disk = disk;
1620 bio_put(bio);
1621 bio = bio_clone(r1_bio->master_bio, GFP_NOIO);
1622 r1_bio->bios[r1_bio->read_disk] = bio;
1623 rdev = conf->mirrors[disk].rdev;
1624 if (printk_ratelimit())
1625 printk(KERN_ERR "raid1: %s: redirecting sector %llu to"
1626 " another mirror\n",
1627 bdevname(rdev->bdev,b),
1628 (unsigned long long)r1_bio->sector);
1629 bio->bi_sector = r1_bio->sector + rdev->data_offset;
1630 bio->bi_bdev = rdev->bdev;
1631 bio->bi_end_io = raid1_end_read_request;
1632 bio->bi_rw = READ | do_sync;
1633 bio->bi_private = r1_bio;
1634 unplug = 1;
1635 generic_make_request(bio);
1636 }
1637 }
1638 }
1639 spin_unlock_irqrestore(&conf->device_lock, flags);
1640 if (unplug)
1641 unplug_slaves(mddev);
1642 }
1643
1644
1645 static int init_resync(conf_t *conf)
1646 {
1647 int buffs;
1648
1649 buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE;
1650 BUG_ON(conf->r1buf_pool);
1651 conf->r1buf_pool = mempool_create(buffs, r1buf_pool_alloc, r1buf_pool_free,
1652 conf->poolinfo);
1653 if (!conf->r1buf_pool)
1654 return -ENOMEM;
1655 conf->next_resync = 0;
1656 return 0;
1657 }
1658
1659 /*
1660 * perform a "sync" on one "block"
1661 *
1662 * We need to make sure that no normal I/O request - particularly write
1663 * requests - conflict with active sync requests.
1664 *
1665 * This is achieved by tracking pending requests and a 'barrier' concept
1666 * that can be installed to exclude normal IO requests.
1667 */
1668
1669 static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster)
1670 {
1671 conf_t *conf = mddev_to_conf(mddev);
1672 r1bio_t *r1_bio;
1673 struct bio *bio;
1674 sector_t max_sector, nr_sectors;
1675 int disk = -1;
1676 int i;
1677 int wonly = -1;
1678 int write_targets = 0, read_targets = 0;
1679 int sync_blocks;
1680 int still_degraded = 0;
1681
1682 if (!conf->r1buf_pool)
1683 {
1684 /*
1685 printk("sync start - bitmap %p\n", mddev->bitmap);
1686 */
1687 if (init_resync(conf))
1688 return 0;
1689 }
1690
1691 max_sector = mddev->size << 1;
1692 if (sector_nr >= max_sector) {
1693 /* If we aborted, we need to abort the
1694 * sync on the 'current' bitmap chunk (there will
1695 * only be one in raid1 resync.
1696 * We can find the current addess in mddev->curr_resync
1697 */
1698 if (mddev->curr_resync < max_sector) /* aborted */
1699 bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
1700 &sync_blocks, 1);
1701 else /* completed sync */
1702 conf->fullsync = 0;
1703
1704 bitmap_close_sync(mddev->bitmap);
1705 close_sync(conf);
1706 return 0;
1707 }
1708
1709 if (mddev->bitmap == NULL &&
1710 mddev->recovery_cp == MaxSector &&
1711 !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
1712 conf->fullsync == 0) {
1713 *skipped = 1;
1714 return max_sector - sector_nr;
1715 }
1716 /* before building a request, check if we can skip these blocks..
1717 * This call the bitmap_start_sync doesn't actually record anything
1718 */
1719 if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
1720 !conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
1721 /* We can skip this block, and probably several more */
1722 *skipped = 1;
1723 return sync_blocks;
1724 }
1725 /*
1726 * If there is non-resync activity waiting for a turn,
1727 * and resync is going fast enough,
1728 * then let it though before starting on this new sync request.
1729 */
1730 if (!go_faster && conf->nr_waiting)
1731 msleep_interruptible(1000);
1732
1733 raise_barrier(conf);
1734
1735 conf->next_resync = sector_nr;
1736
1737 r1_bio = mempool_alloc(conf->r1buf_pool, GFP_NOIO);
1738 rcu_read_lock();
1739 /*
1740 * If we get a correctably read error during resync or recovery,
1741 * we might want to read from a different device. So we
1742 * flag all drives that could conceivably be read from for READ,
1743 * and any others (which will be non-In_sync devices) for WRITE.
1744 * If a read fails, we try reading from something else for which READ
1745 * is OK.
1746 */
1747
1748 r1_bio->mddev = mddev;
1749 r1_bio->sector = sector_nr;
1750 r1_bio->state = 0;
1751 set_bit(R1BIO_IsSync, &r1_bio->state);
1752
1753 for (i=0; i < conf->raid_disks; i++) {
1754 mdk_rdev_t *rdev;
1755 bio = r1_bio->bios[i];
1756
1757 /* take from bio_init */
1758 bio->bi_next = NULL;
1759 bio->bi_flags |= 1 << BIO_UPTODATE;
1760 bio->bi_rw = READ;
1761 bio->bi_vcnt = 0;
1762 bio->bi_idx = 0;
1763 bio->bi_phys_segments = 0;
1764 bio->bi_hw_segments = 0;
1765 bio->bi_size = 0;
1766 bio->bi_end_io = NULL;
1767 bio->bi_private = NULL;
1768
1769 rdev = rcu_dereference(conf->mirrors[i].rdev);
1770 if (rdev == NULL ||
1771 test_bit(Faulty, &rdev->flags)) {
1772 still_degraded = 1;
1773 continue;
1774 } else if (!test_bit(In_sync, &rdev->flags)) {
1775 bio->bi_rw = WRITE;
1776 bio->bi_end_io = end_sync_write;
1777 write_targets ++;
1778 } else {
1779 /* may need to read from here */
1780 bio->bi_rw = READ;
1781 bio->bi_end_io = end_sync_read;
1782 if (test_bit(WriteMostly, &rdev->flags)) {
1783 if (wonly < 0)
1784 wonly = i;
1785 } else {
1786 if (disk < 0)
1787 disk = i;
1788 }
1789 read_targets++;
1790 }
1791 atomic_inc(&rdev->nr_pending);
1792 bio->bi_sector = sector_nr + rdev->data_offset;
1793 bio->bi_bdev = rdev->bdev;
1794 bio->bi_private = r1_bio;
1795 }
1796 rcu_read_unlock();
1797 if (disk < 0)
1798 disk = wonly;
1799 r1_bio->read_disk = disk;
1800
1801 if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) && read_targets > 0)
1802 /* extra read targets are also write targets */
1803 write_targets += read_targets-1;
1804
1805 if (write_targets == 0 || read_targets == 0) {
1806 /* There is nowhere to write, so all non-sync
1807 * drives must be failed - so we are finished
1808 */
1809 sector_t rv = max_sector - sector_nr;
1810 *skipped = 1;
1811 put_buf(r1_bio);
1812 return rv;
1813 }
1814
1815 nr_sectors = 0;
1816 sync_blocks = 0;
1817 do {
1818 struct page *page;
1819 int len = PAGE_SIZE;
1820 if (sector_nr + (len>>9) > max_sector)
1821 len = (max_sector - sector_nr) << 9;
1822 if (len == 0)
1823 break;
1824 if (sync_blocks == 0) {
1825 if (!bitmap_start_sync(mddev->bitmap, sector_nr,
1826 &sync_blocks, still_degraded) &&
1827 !conf->fullsync &&
1828 !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
1829 break;
1830 BUG_ON(sync_blocks < (PAGE_SIZE>>9));
1831 if (len > (sync_blocks<<9))
1832 len = sync_blocks<<9;
1833 }
1834
1835 for (i=0 ; i < conf->raid_disks; i++) {
1836 bio = r1_bio->bios[i];
1837 if (bio->bi_end_io) {
1838 page = bio->bi_io_vec[bio->bi_vcnt].bv_page;
1839 if (bio_add_page(bio, page, len, 0) == 0) {
1840 /* stop here */
1841 bio->bi_io_vec[bio->bi_vcnt].bv_page = page;
1842 while (i > 0) {
1843 i--;
1844 bio = r1_bio->bios[i];
1845 if (bio->bi_end_io==NULL)
1846 continue;
1847 /* remove last page from this bio */
1848 bio->bi_vcnt--;
1849 bio->bi_size -= len;
1850 bio->bi_flags &= ~(1<< BIO_SEG_VALID);
1851 }
1852 goto bio_full;
1853 }
1854 }
1855 }
1856 nr_sectors += len>>9;
1857 sector_nr += len>>9;
1858 sync_blocks -= (len>>9);
1859 } while (r1_bio->bios[disk]->bi_vcnt < RESYNC_PAGES);
1860 bio_full:
1861 r1_bio->sectors = nr_sectors;
1862
1863 /* For a user-requested sync, we read all readable devices and do a
1864 * compare
1865 */
1866 if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
1867 atomic_set(&r1_bio->remaining, read_targets);
1868 for (i=0; i<conf->raid_disks; i++) {
1869 bio = r1_bio->bios[i];
1870 if (bio->bi_end_io == end_sync_read) {
1871 md_sync_acct(bio->bi_bdev, nr_sectors);
1872 generic_make_request(bio);
1873 }
1874 }
1875 } else {
1876 atomic_set(&r1_bio->remaining, 1);
1877 bio = r1_bio->bios[r1_bio->read_disk];
1878 md_sync_acct(bio->bi_bdev, nr_sectors);
1879 generic_make_request(bio);
1880
1881 }
1882 return nr_sectors;
1883 }
1884
1885 static int run(mddev_t *mddev)
1886 {
1887 conf_t *conf;
1888 int i, j, disk_idx;
1889 mirror_info_t *disk;
1890 mdk_rdev_t *rdev;
1891 struct list_head *tmp;
1892
1893 if (mddev->level != 1) {
1894 printk("raid1: %s: raid level not set to mirroring (%d)\n",
1895 mdname(mddev), mddev->level);
1896 goto out;
1897 }
1898 if (mddev->reshape_position != MaxSector) {
1899 printk("raid1: %s: reshape_position set but not supported\n",
1900 mdname(mddev));
1901 goto out;
1902 }
1903 /*
1904 * copy the already verified devices into our private RAID1
1905 * bookkeeping area. [whatever we allocate in run(),
1906 * should be freed in stop()]
1907 */
1908 conf = kzalloc(sizeof(conf_t), GFP_KERNEL);
1909 mddev->private = conf;
1910 if (!conf)
1911 goto out_no_mem;
1912
1913 conf->mirrors = kzalloc(sizeof(struct mirror_info)*mddev->raid_disks,
1914 GFP_KERNEL);
1915 if (!conf->mirrors)
1916 goto out_no_mem;
1917
1918 conf->tmppage = alloc_page(GFP_KERNEL);
1919 if (!conf->tmppage)
1920 goto out_no_mem;
1921
1922 conf->poolinfo = kmalloc(sizeof(*conf->poolinfo), GFP_KERNEL);
1923 if (!conf->poolinfo)
1924 goto out_no_mem;
1925 conf->poolinfo->mddev = mddev;
1926 conf->poolinfo->raid_disks = mddev->raid_disks;
1927 conf->r1bio_pool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc,
1928 r1bio_pool_free,
1929 conf->poolinfo);
1930 if (!conf->r1bio_pool)
1931 goto out_no_mem;
1932
1933 ITERATE_RDEV(mddev, rdev, tmp) {
1934 disk_idx = rdev->raid_disk;
1935 if (disk_idx >= mddev->raid_disks
1936 || disk_idx < 0)
1937 continue;
1938 disk = conf->mirrors + disk_idx;
1939
1940 disk->rdev = rdev;
1941
1942 blk_queue_stack_limits(mddev->queue,
1943 rdev->bdev->bd_disk->queue);
1944 /* as we don't honour merge_bvec_fn, we must never risk
1945 * violating it, so limit ->max_sector to one PAGE, as
1946 * a one page request is never in violation.
1947 */
1948 if (rdev->bdev->bd_disk->queue->merge_bvec_fn &&
1949 mddev->queue->max_sectors > (PAGE_SIZE>>9))
1950 blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9);
1951
1952 disk->head_position = 0;
1953 }
1954 conf->raid_disks = mddev->raid_disks;
1955 conf->mddev = mddev;
1956 spin_lock_init(&conf->device_lock);
1957 INIT_LIST_HEAD(&conf->retry_list);
1958
1959 spin_lock_init(&conf->resync_lock);
1960 init_waitqueue_head(&conf->wait_barrier);
1961
1962 bio_list_init(&conf->pending_bio_list);
1963 bio_list_init(&conf->flushing_bio_list);
1964
1965
1966 mddev->degraded = 0;
1967 for (i = 0; i < conf->raid_disks; i++) {
1968
1969 disk = conf->mirrors + i;
1970
1971 if (!disk->rdev ||
1972 !test_bit(In_sync, &disk->rdev->flags)) {
1973 disk->head_position = 0;
1974 mddev->degraded++;
1975 conf->fullsync = 1;
1976 }
1977 }
1978 if (mddev->degraded == conf->raid_disks) {
1979 printk(KERN_ERR "raid1: no operational mirrors for %s\n",
1980 mdname(mddev));
1981 goto out_free_conf;
1982 }
1983 if (conf->raid_disks - mddev->degraded == 1)
1984 mddev->recovery_cp = MaxSector;
1985
1986 /*
1987 * find the first working one and use it as a starting point
1988 * to read balancing.
1989 */
1990 for (j = 0; j < conf->raid_disks &&
1991 (!conf->mirrors[j].rdev ||
1992 !test_bit(In_sync, &conf->mirrors[j].rdev->flags)) ; j++)
1993 /* nothing */;
1994 conf->last_used = j;
1995
1996
1997 mddev->thread = md_register_thread(raid1d, mddev, "%s_raid1");
1998 if (!mddev->thread) {
1999 printk(KERN_ERR
2000 "raid1: couldn't allocate thread for %s\n",
2001 mdname(mddev));
2002 goto out_free_conf;
2003 }
2004
2005 printk(KERN_INFO
2006 "raid1: raid set %s active with %d out of %d mirrors\n",
2007 mdname(mddev), mddev->raid_disks - mddev->degraded,
2008 mddev->raid_disks);
2009 /*
2010 * Ok, everything is just fine now
2011 */
2012 mddev->array_size = mddev->size;
2013
2014 mddev->queue->unplug_fn = raid1_unplug;
2015 mddev->queue->issue_flush_fn = raid1_issue_flush;
2016 mddev->queue->backing_dev_info.congested_fn = raid1_congested;
2017 mddev->queue->backing_dev_info.congested_data = mddev;
2018
2019 return 0;
2020
2021 out_no_mem:
2022 printk(KERN_ERR "raid1: couldn't allocate memory for %s\n",
2023 mdname(mddev));
2024
2025 out_free_conf:
2026 if (conf) {
2027 if (conf->r1bio_pool)
2028 mempool_destroy(conf->r1bio_pool);
2029 kfree(conf->mirrors);
2030 safe_put_page(conf->tmppage);
2031 kfree(conf->poolinfo);
2032 kfree(conf);
2033 mddev->private = NULL;
2034 }
2035 out:
2036 return -EIO;
2037 }
2038
2039 static int stop(mddev_t *mddev)
2040 {
2041 conf_t *conf = mddev_to_conf(mddev);
2042 struct bitmap *bitmap = mddev->bitmap;
2043 int behind_wait = 0;
2044
2045 /* wait for behind writes to complete */
2046 while (bitmap && atomic_read(&bitmap->behind_writes) > 0) {
2047 behind_wait++;
2048 printk(KERN_INFO "raid1: behind writes in progress on device %s, waiting to stop (%d)\n", mdname(mddev), behind_wait);
2049 set_current_state(TASK_UNINTERRUPTIBLE);
2050 schedule_timeout(HZ); /* wait a second */
2051 /* need to kick something here to make sure I/O goes? */
2052 }
2053
2054 md_unregister_thread(mddev->thread);
2055 mddev->thread = NULL;
2056 blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
2057 if (conf->r1bio_pool)
2058 mempool_destroy(conf->r1bio_pool);
2059 kfree(conf->mirrors);
2060 kfree(conf->poolinfo);
2061 kfree(conf);
2062 mddev->private = NULL;
2063 return 0;
2064 }
2065
2066 static int raid1_resize(mddev_t *mddev, sector_t sectors)
2067 {
2068 /* no resync is happening, and there is enough space
2069 * on all devices, so we can resize.
2070 * We need to make sure resync covers any new space.
2071 * If the array is shrinking we should possibly wait until
2072 * any io in the removed space completes, but it hardly seems
2073 * worth it.
2074 */
2075 mddev->array_size = sectors>>1;
2076 set_capacity(mddev->gendisk, mddev->array_size << 1);
2077 mddev->changed = 1;
2078 if (mddev->array_size > mddev->size && mddev->recovery_cp == MaxSector) {
2079 mddev->recovery_cp = mddev->size << 1;
2080 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
2081 }
2082 mddev->size = mddev->array_size;
2083 mddev->resync_max_sectors = sectors;
2084 return 0;
2085 }
2086
2087 static int raid1_reshape(mddev_t *mddev)
2088 {
2089 /* We need to:
2090 * 1/ resize the r1bio_pool
2091 * 2/ resize conf->mirrors
2092 *
2093 * We allocate a new r1bio_pool if we can.
2094 * Then raise a device barrier and wait until all IO stops.
2095 * Then resize conf->mirrors and swap in the new r1bio pool.
2096 *
2097 * At the same time, we "pack" the devices so that all the missing
2098 * devices have the higher raid_disk numbers.
2099 */
2100 mempool_t *newpool, *oldpool;
2101 struct pool_info *newpoolinfo;
2102 mirror_info_t *newmirrors;
2103 conf_t *conf = mddev_to_conf(mddev);
2104 int cnt, raid_disks;
2105 unsigned long flags;
2106 int d, d2;
2107
2108 /* Cannot change chunk_size, layout, or level */
2109 if (mddev->chunk_size != mddev->new_chunk ||
2110 mddev->layout != mddev->new_layout ||
2111 mddev->level != mddev->new_level) {
2112 mddev->new_chunk = mddev->chunk_size;
2113 mddev->new_layout = mddev->layout;
2114 mddev->new_level = mddev->level;
2115 return -EINVAL;
2116 }
2117
2118 md_allow_write(mddev);
2119
2120 raid_disks = mddev->raid_disks + mddev->delta_disks;
2121
2122 if (raid_disks < conf->raid_disks) {
2123 cnt=0;
2124 for (d= 0; d < conf->raid_disks; d++)
2125 if (conf->mirrors[d].rdev)
2126 cnt++;
2127 if (cnt > raid_disks)
2128 return -EBUSY;
2129 }
2130
2131 newpoolinfo = kmalloc(sizeof(*newpoolinfo), GFP_KERNEL);
2132 if (!newpoolinfo)
2133 return -ENOMEM;
2134 newpoolinfo->mddev = mddev;
2135 newpoolinfo->raid_disks = raid_disks;
2136
2137 newpool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc,
2138 r1bio_pool_free, newpoolinfo);
2139 if (!newpool) {
2140 kfree(newpoolinfo);
2141 return -ENOMEM;
2142 }
2143 newmirrors = kzalloc(sizeof(struct mirror_info) * raid_disks, GFP_KERNEL);
2144 if (!newmirrors) {
2145 kfree(newpoolinfo);
2146 mempool_destroy(newpool);
2147 return -ENOMEM;
2148 }
2149
2150 raise_barrier(conf);
2151
2152 /* ok, everything is stopped */
2153 oldpool = conf->r1bio_pool;
2154 conf->r1bio_pool = newpool;
2155
2156 for (d=d2=0; d < conf->raid_disks; d++)
2157 if (conf->mirrors[d].rdev) {
2158 conf->mirrors[d].rdev->raid_disk = d2;
2159 newmirrors[d2++].rdev = conf->mirrors[d].rdev;
2160 }
2161 kfree(conf->mirrors);
2162 conf->mirrors = newmirrors;
2163 kfree(conf->poolinfo);
2164 conf->poolinfo = newpoolinfo;
2165
2166 spin_lock_irqsave(&conf->device_lock, flags);
2167 mddev->degraded += (raid_disks - conf->raid_disks);
2168 spin_unlock_irqrestore(&conf->device_lock, flags);
2169 conf->raid_disks = mddev->raid_disks = raid_disks;
2170 mddev->delta_disks = 0;
2171
2172 conf->last_used = 0; /* just make sure it is in-range */
2173 lower_barrier(conf);
2174
2175 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
2176 md_wakeup_thread(mddev->thread);
2177
2178 mempool_destroy(oldpool);
2179 return 0;
2180 }
2181
2182 static void raid1_quiesce(mddev_t *mddev, int state)
2183 {
2184 conf_t *conf = mddev_to_conf(mddev);
2185
2186 switch(state) {
2187 case 1:
2188 raise_barrier(conf);
2189 break;
2190 case 0:
2191 lower_barrier(conf);
2192 break;
2193 }
2194 }
2195
2196
2197 static struct mdk_personality raid1_personality =
2198 {
2199 .name = "raid1",
2200 .level = 1,
2201 .owner = THIS_MODULE,
2202 .make_request = make_request,
2203 .run = run,
2204 .stop = stop,
2205 .status = status,
2206 .error_handler = error,
2207 .hot_add_disk = raid1_add_disk,
2208 .hot_remove_disk= raid1_remove_disk,
2209 .spare_active = raid1_spare_active,
2210 .sync_request = sync_request,
2211 .resize = raid1_resize,
2212 .check_reshape = raid1_reshape,
2213 .quiesce = raid1_quiesce,
2214 };
2215
2216 static int __init raid_init(void)
2217 {
2218 return register_md_personality(&raid1_personality);
2219 }
2220
2221 static void raid_exit(void)
2222 {
2223 unregister_md_personality(&raid1_personality);
2224 }
2225
2226 module_init(raid_init);
2227 module_exit(raid_exit);
2228 MODULE_LICENSE("GPL");
2229 MODULE_ALIAS("md-personality-3"); /* RAID1 */
2230 MODULE_ALIAS("md-raid1");
2231 MODULE_ALIAS("md-level-1");
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