1 /*
2 * raid1.c : Multiple Devices driver for Linux
3 *
4 * Copyright (C) 1999, 2000, 2001 Ingo Molnar, Red Hat
5 *
6 * Copyright (C) 1996, 1997, 1998 Ingo Molnar, Miguel de Icaza, Gadi Oxman
7 *
8 * RAID-1 management functions.
9 *
10 * Better read-balancing code written by Mika Kuoppala <miku@iki.fi>, 2000
11 *
12 * Fixes to reconstruction by Jakob Østergaard" <jakob@ostenfeld.dk>
13 * Various fixes by Neil Brown <neilb@cse.unsw.edu.au>
14 *
15 * Changes by Peter T. Breuer <ptb@it.uc3m.es> 31/1/2003 to support
16 * bitmapped intelligence in resync:
17 *
18 * - bitmap marked during normal i/o
19 * - bitmap used to skip nondirty blocks during sync
20 *
21 * Additions to bitmap code, (C) 2003-2004 Paul Clements, SteelEye Technology:
22 * - persistent bitmap code
23 *
24 * This program is free software; you can redistribute it and/or modify
25 * it under the terms of the GNU General Public License as published by
26 * the Free Software Foundation; either version 2, or (at your option)
27 * any later version.
28 *
29 * You should have received a copy of the GNU General Public License
30 * (for example /usr/src/linux/COPYING); if not, write to the Free
31 * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
32 */
33
34 #include <linux/delay.h>
35 #include <linux/blkdev.h>
36 #include <linux/seq_file.h>
37 #include "md.h"
38 #include "raid1.h"
39 #include "bitmap.h"
40
41 #define DEBUG 0
42 #if DEBUG
43 #define PRINTK(x...) printk(x)
44 #else
45 #define PRINTK(x...)
46 #endif
47
48 /*
49 * Number of guaranteed r1bios in case of extreme VM load:
50 */
51 #define NR_RAID1_BIOS 256
52
53
54 static void unplug_slaves(mddev_t *mddev);
55
56 static void allow_barrier(conf_t *conf);
57 static void lower_barrier(conf_t *conf);
58
59 static void * r1bio_pool_alloc(gfp_t gfp_flags, void *data)
60 {
61 struct pool_info *pi = data;
62 r1bio_t *r1_bio;
63 int size = offsetof(r1bio_t, bios[pi->raid_disks]);
64
65 /* allocate a r1bio with room for raid_disks entries in the bios array */
66 r1_bio = kzalloc(size, gfp_flags);
67 if (!r1_bio)
68 unplug_slaves(pi->mddev);
69
70 return r1_bio;
71 }
72
73 static void r1bio_pool_free(void *r1_bio, void *data)
74 {
75 kfree(r1_bio);
76 }
77
78 #define RESYNC_BLOCK_SIZE (64*1024)
79 //#define RESYNC_BLOCK_SIZE PAGE_SIZE
80 #define RESYNC_SECTORS (RESYNC_BLOCK_SIZE >> 9)
81 #define RESYNC_PAGES ((RESYNC_BLOCK_SIZE + PAGE_SIZE-1) / PAGE_SIZE)
82 #define RESYNC_WINDOW (2048*1024)
83
84 static void * r1buf_pool_alloc(gfp_t gfp_flags, void *data)
85 {
86 struct pool_info *pi = data;
87 struct page *page;
88 r1bio_t *r1_bio;
89 struct bio *bio;
90 int i, j;
91
92 r1_bio = r1bio_pool_alloc(gfp_flags, pi);
93 if (!r1_bio) {
94 unplug_slaves(pi->mddev);
95 return NULL;
96 }
97
98 /*
99 * Allocate bios : 1 for reading, n-1 for writing
100 */
101 for (j = pi->raid_disks ; j-- ; ) {
102 bio = bio_alloc(gfp_flags, RESYNC_PAGES);
103 if (!bio)
104 goto out_free_bio;
105 r1_bio->bios[j] = bio;
106 }
107 /*
108 * Allocate RESYNC_PAGES data pages and attach them to
109 * the first bio.
110 * If this is a user-requested check/repair, allocate
111 * RESYNC_PAGES for each bio.
112 */
113 if (test_bit(MD_RECOVERY_REQUESTED, &pi->mddev->recovery))
114 j = pi->raid_disks;
115 else
116 j = 1;
117 while(j--) {
118 bio = r1_bio->bios[j];
119 for (i = 0; i < RESYNC_PAGES; i++) {
120 page = alloc_page(gfp_flags);
121 if (unlikely(!page))
122 goto out_free_pages;
123
124 bio->bi_io_vec[i].bv_page = page;
125 bio->bi_vcnt = i+1;
126 }
127 }
128 /* If not user-requests, copy the page pointers to all bios */
129 if (!test_bit(MD_RECOVERY_REQUESTED, &pi->mddev->recovery)) {
130 for (i=0; i<RESYNC_PAGES ; i++)
131 for (j=1; j<pi->raid_disks; j++)
132 r1_bio->bios[j]->bi_io_vec[i].bv_page =
133 r1_bio->bios[0]->bi_io_vec[i].bv_page;
134 }
135
136 r1_bio->master_bio = NULL;
137
138 return r1_bio;
139
140 out_free_pages:
141 for (j=0 ; j < pi->raid_disks; j++)
142 for (i=0; i < r1_bio->bios[j]->bi_vcnt ; i++)
143 put_page(r1_bio->bios[j]->bi_io_vec[i].bv_page);
144 j = -1;
145 out_free_bio:
146 while ( ++j < pi->raid_disks )
147 bio_put(r1_bio->bios[j]);
148 r1bio_pool_free(r1_bio, data);
149 return NULL;
150 }
151
152 static void r1buf_pool_free(void *__r1_bio, void *data)
153 {
154 struct pool_info *pi = data;
155 int i,j;
156 r1bio_t *r1bio = __r1_bio;
157
158 for (i = 0; i < RESYNC_PAGES; i++)
159 for (j = pi->raid_disks; j-- ;) {
160 if (j == 0 ||
161 r1bio->bios[j]->bi_io_vec[i].bv_page !=
162 r1bio->bios[0]->bi_io_vec[i].bv_page)
163 safe_put_page(r1bio->bios[j]->bi_io_vec[i].bv_page);
164 }
165 for (i=0 ; i < pi->raid_disks; i++)
166 bio_put(r1bio->bios[i]);
167
168 r1bio_pool_free(r1bio, data);
169 }
170
171 static void put_all_bios(conf_t *conf, r1bio_t *r1_bio)
172 {
173 int i;
174
175 for (i = 0; i < conf->raid_disks; i++) {
176 struct bio **bio = r1_bio->bios + i;
177 if (*bio && *bio != IO_BLOCKED)
178 bio_put(*bio);
179 *bio = NULL;
180 }
181 }
182
183 static void free_r1bio(r1bio_t *r1_bio)
184 {
185 conf_t *conf = r1_bio->mddev->private;
186
187 /*
188 * Wake up any possible resync thread that waits for the device
189 * to go idle.
190 */
191 allow_barrier(conf);
192
193 put_all_bios(conf, r1_bio);
194 mempool_free(r1_bio, conf->r1bio_pool);
195 }
196
197 static void put_buf(r1bio_t *r1_bio)
198 {
199 conf_t *conf = r1_bio->mddev->private;
200 int i;
201
202 for (i=0; i<conf->raid_disks; i++) {
203 struct bio *bio = r1_bio->bios[i];
204 if (bio->bi_end_io)
205 rdev_dec_pending(conf->mirrors[i].rdev, r1_bio->mddev);
206 }
207
208 mempool_free(r1_bio, conf->r1buf_pool);
209
210 lower_barrier(conf);
211 }
212
213 static void reschedule_retry(r1bio_t *r1_bio)
214 {
215 unsigned long flags;
216 mddev_t *mddev = r1_bio->mddev;
217 conf_t *conf = mddev->private;
218
219 spin_lock_irqsave(&conf->device_lock, flags);
220 list_add(&r1_bio->retry_list, &conf->retry_list);
221 conf->nr_queued ++;
222 spin_unlock_irqrestore(&conf->device_lock, flags);
223
224 wake_up(&conf->wait_barrier);
225 md_wakeup_thread(mddev->thread);
226 }
227
228 /*
229 * raid_end_bio_io() is called when we have finished servicing a mirrored
230 * operation and are ready to return a success/failure code to the buffer
231 * cache layer.
232 */
233 static void raid_end_bio_io(r1bio_t *r1_bio)
234 {
235 struct bio *bio = r1_bio->master_bio;
236
237 /* if nobody has done the final endio yet, do it now */
238 if (!test_and_set_bit(R1BIO_Returned, &r1_bio->state)) {
239 PRINTK(KERN_DEBUG "raid1: sync end %s on sectors %llu-%llu\n",
240 (bio_data_dir(bio) == WRITE) ? "write" : "read",
241 (unsigned long long) bio->bi_sector,
242 (unsigned long long) bio->bi_sector +
243 (bio->bi_size >> 9) - 1);
244
245 bio_endio(bio,
246 test_bit(R1BIO_Uptodate, &r1_bio->state) ? 0 : -EIO);
247 }
248 free_r1bio(r1_bio);
249 }
250
251 /*
252 * Update disk head position estimator based on IRQ completion info.
253 */
254 static inline void update_head_pos(int disk, r1bio_t *r1_bio)
255 {
256 conf_t *conf = r1_bio->mddev->private;
257
258 conf->mirrors[disk].head_position =
259 r1_bio->sector + (r1_bio->sectors);
260 }
261
262 static void raid1_end_read_request(struct bio *bio, int error)
263 {
264 int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
265 r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private);
266 int mirror;
267 conf_t *conf = r1_bio->mddev->private;
268
269 mirror = r1_bio->read_disk;
270 /*
271 * this branch is our 'one mirror IO has finished' event handler:
272 */
273 update_head_pos(mirror, r1_bio);
274
275 if (uptodate)
276 set_bit(R1BIO_Uptodate, &r1_bio->state);
277 else {
278 /* If all other devices have failed, we want to return
279 * the error upwards rather than fail the last device.
280 * Here we redefine "uptodate" to mean "Don't want to retry"
281 */
282 unsigned long flags;
283 spin_lock_irqsave(&conf->device_lock, flags);
284 if (r1_bio->mddev->degraded == conf->raid_disks ||
285 (r1_bio->mddev->degraded == conf->raid_disks-1 &&
286 !test_bit(Faulty, &conf->mirrors[mirror].rdev->flags)))
287 uptodate = 1;
288 spin_unlock_irqrestore(&conf->device_lock, flags);
289 }
290
291 if (uptodate)
292 raid_end_bio_io(r1_bio);
293 else {
294 /*
295 * oops, read error:
296 */
297 char b[BDEVNAME_SIZE];
298 if (printk_ratelimit())
299 printk(KERN_ERR "raid1: %s: rescheduling sector %llu\n",
300 bdevname(conf->mirrors[mirror].rdev->bdev,b), (unsigned long long)r1_bio->sector);
301 reschedule_retry(r1_bio);
302 }
303
304 rdev_dec_pending(conf->mirrors[mirror].rdev, conf->mddev);
305 }
306
307 static void raid1_end_write_request(struct bio *bio, 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 = r1_bio->mddev->private;
313 struct bio *to_put = NULL;
314
315
316 for (mirror = 0; mirror < conf->raid_disks; mirror++)
317 if (r1_bio->bios[mirror] == bio)
318 break;
319
320 if (error == -EOPNOTSUPP && test_bit(R1BIO_Barrier, &r1_bio->state)) {
321 set_bit(BarriersNotsupp, &conf->mirrors[mirror].rdev->flags);
322 set_bit(R1BIO_BarrierRetry, &r1_bio->state);
323 r1_bio->mddev->barriers_work = 0;
324 /* Don't rdev_dec_pending in this branch - keep it for the retry */
325 } else {
326 /*
327 * this branch is our 'one mirror IO has finished' event handler:
328 */
329 r1_bio->bios[mirror] = NULL;
330 to_put = bio;
331 if (!uptodate) {
332 md_error(r1_bio->mddev, conf->mirrors[mirror].rdev);
333 /* an I/O failed, we can't clear the bitmap */
334 set_bit(R1BIO_Degraded, &r1_bio->state);
335 } else
336 /*
337 * Set R1BIO_Uptodate in our master bio, so that
338 * we will return a good error code for to the higher
339 * levels even if IO on some other mirrored buffer fails.
340 *
341 * The 'master' represents the composite IO operation to
342 * user-side. So if something waits for IO, then it will
343 * wait for the 'master' bio.
344 */
345 set_bit(R1BIO_Uptodate, &r1_bio->state);
346
347 update_head_pos(mirror, r1_bio);
348
349 if (behind) {
350 if (test_bit(WriteMostly, &conf->mirrors[mirror].rdev->flags))
351 atomic_dec(&r1_bio->behind_remaining);
352
353 /* In behind mode, we ACK the master bio once the I/O has safely
354 * reached all non-writemostly disks. Setting the Returned bit
355 * ensures that this gets done only once -- we don't ever want to
356 * return -EIO here, instead we'll wait */
357
358 if (atomic_read(&r1_bio->behind_remaining) >= (atomic_read(&r1_bio->remaining)-1) &&
359 test_bit(R1BIO_Uptodate, &r1_bio->state)) {
360 /* Maybe we can return now */
361 if (!test_and_set_bit(R1BIO_Returned, &r1_bio->state)) {
362 struct bio *mbio = r1_bio->master_bio;
363 PRINTK(KERN_DEBUG "raid1: behind end write sectors %llu-%llu\n",
364 (unsigned long long) mbio->bi_sector,
365 (unsigned long long) mbio->bi_sector +
366 (mbio->bi_size >> 9) - 1);
367 bio_endio(mbio, 0);
368 }
369 }
370 }
371 rdev_dec_pending(conf->mirrors[mirror].rdev, conf->mddev);
372 }
373 /*
374 *
375 * Let's see if all mirrored write operations have finished
376 * already.
377 */
378 if (atomic_dec_and_test(&r1_bio->remaining)) {
379 if (test_bit(R1BIO_BarrierRetry, &r1_bio->state))
380 reschedule_retry(r1_bio);
381 else {
382 /* it really is the end of this request */
383 if (test_bit(R1BIO_BehindIO, &r1_bio->state)) {
384 /* free extra copy of the data pages */
385 int i = bio->bi_vcnt;
386 while (i--)
387 safe_put_page(bio->bi_io_vec[i].bv_page);
388 }
389 /* clear the bitmap if all writes complete successfully */
390 bitmap_endwrite(r1_bio->mddev->bitmap, r1_bio->sector,
391 r1_bio->sectors,
392 !test_bit(R1BIO_Degraded, &r1_bio->state),
393 behind);
394 md_write_end(r1_bio->mddev);
395 raid_end_bio_io(r1_bio);
396 }
397 }
398
399 if (to_put)
400 bio_put(to_put);
401 }
402
403
404 /*
405 * This routine returns the disk from which the requested read should
406 * be done. There is a per-array 'next expected sequential IO' sector
407 * number - if this matches on the next IO then we use the last disk.
408 * There is also a per-disk 'last know head position' sector that is
409 * maintained from IRQ contexts, both the normal and the resync IO
410 * completion handlers update this position correctly. If there is no
411 * perfect sequential match then we pick the disk whose head is closest.
412 *
413 * If there are 2 mirrors in the same 2 devices, performance degrades
414 * because position is mirror, not device based.
415 *
416 * The rdev for the device selected will have nr_pending incremented.
417 */
418 static int read_balance(conf_t *conf, r1bio_t *r1_bio)
419 {
420 const unsigned long this_sector = r1_bio->sector;
421 int new_disk = conf->last_used, disk = new_disk;
422 int wonly_disk = -1;
423 const int sectors = r1_bio->sectors;
424 sector_t new_distance, current_distance;
425 mdk_rdev_t *rdev;
426
427 rcu_read_lock();
428 /*
429 * Check if we can balance. We can balance on the whole
430 * device if no resync is going on, or below the resync window.
431 * We take the first readable disk when above the resync window.
432 */
433 retry:
434 if (conf->mddev->recovery_cp < MaxSector &&
435 (this_sector + sectors >= conf->next_resync)) {
436 /* Choose the first operation device, for consistancy */
437 new_disk = 0;
438
439 for (rdev = rcu_dereference(conf->mirrors[new_disk].rdev);
440 r1_bio->bios[new_disk] == IO_BLOCKED ||
441 !rdev || !test_bit(In_sync, &rdev->flags)
442 || test_bit(WriteMostly, &rdev->flags);
443 rdev = rcu_dereference(conf->mirrors[++new_disk].rdev)) {
444
445 if (rdev && test_bit(In_sync, &rdev->flags) &&
446 r1_bio->bios[new_disk] != IO_BLOCKED)
447 wonly_disk = new_disk;
448
449 if (new_disk == conf->raid_disks - 1) {
450 new_disk = wonly_disk;
451 break;
452 }
453 }
454 goto rb_out;
455 }
456
457
458 /* make sure the disk is operational */
459 for (rdev = rcu_dereference(conf->mirrors[new_disk].rdev);
460 r1_bio->bios[new_disk] == IO_BLOCKED ||
461 !rdev || !test_bit(In_sync, &rdev->flags) ||
462 test_bit(WriteMostly, &rdev->flags);
463 rdev = rcu_dereference(conf->mirrors[new_disk].rdev)) {
464
465 if (rdev && test_bit(In_sync, &rdev->flags) &&
466 r1_bio->bios[new_disk] != IO_BLOCKED)
467 wonly_disk = new_disk;
468
469 if (new_disk <= 0)
470 new_disk = conf->raid_disks;
471 new_disk--;
472 if (new_disk == disk) {
473 new_disk = wonly_disk;
474 break;
475 }
476 }
477
478 if (new_disk < 0)
479 goto rb_out;
480
481 disk = new_disk;
482 /* now disk == new_disk == starting point for search */
483
484 /*
485 * Don't change to another disk for sequential reads:
486 */
487 if (conf->next_seq_sect == this_sector)
488 goto rb_out;
489 if (this_sector == conf->mirrors[new_disk].head_position)
490 goto rb_out;
491
492 current_distance = abs(this_sector - conf->mirrors[disk].head_position);
493
494 /* Find the disk whose head is closest */
495
496 do {
497 if (disk <= 0)
498 disk = conf->raid_disks;
499 disk--;
500
501 rdev = rcu_dereference(conf->mirrors[disk].rdev);
502
503 if (!rdev || r1_bio->bios[disk] == IO_BLOCKED ||
504 !test_bit(In_sync, &rdev->flags) ||
505 test_bit(WriteMostly, &rdev->flags))
506 continue;
507
508 if (!atomic_read(&rdev->nr_pending)) {
509 new_disk = disk;
510 break;
511 }
512 new_distance = abs(this_sector - conf->mirrors[disk].head_position);
513 if (new_distance < current_distance) {
514 current_distance = new_distance;
515 new_disk = disk;
516 }
517 } while (disk != conf->last_used);
518
519 rb_out:
520
521
522 if (new_disk >= 0) {
523 rdev = rcu_dereference(conf->mirrors[new_disk].rdev);
524 if (!rdev)
525 goto retry;
526 atomic_inc(&rdev->nr_pending);
527 if (!test_bit(In_sync, &rdev->flags)) {
528 /* cannot risk returning a device that failed
529 * before we inc'ed nr_pending
530 */
531 rdev_dec_pending(rdev, conf->mddev);
532 goto retry;
533 }
534 conf->next_seq_sect = this_sector + sectors;
535 conf->last_used = new_disk;
536 }
537 rcu_read_unlock();
538
539 return new_disk;
540 }
541
542 static void unplug_slaves(mddev_t *mddev)
543 {
544 conf_t *conf = mddev->private;
545 int i;
546
547 rcu_read_lock();
548 for (i=0; i<mddev->raid_disks; i++) {
549 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
550 if (rdev && !test_bit(Faulty, &rdev->flags) && atomic_read(&rdev->nr_pending)) {
551 struct request_queue *r_queue = bdev_get_queue(rdev->bdev);
552
553 atomic_inc(&rdev->nr_pending);
554 rcu_read_unlock();
555
556 blk_unplug(r_queue);
557
558 rdev_dec_pending(rdev, mddev);
559 rcu_read_lock();
560 }
561 }
562 rcu_read_unlock();
563 }
564
565 static void raid1_unplug(struct request_queue *q)
566 {
567 mddev_t *mddev = q->queuedata;
568
569 unplug_slaves(mddev);
570 md_wakeup_thread(mddev->thread);
571 }
572
573 static int raid1_congested(void *data, int bits)
574 {
575 mddev_t *mddev = data;
576 conf_t *conf = mddev->private;
577 int i, ret = 0;
578
579 rcu_read_lock();
580 for (i = 0; i < mddev->raid_disks; i++) {
581 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
582 if (rdev && !test_bit(Faulty, &rdev->flags)) {
583 struct request_queue *q = bdev_get_queue(rdev->bdev);
584
585 /* Note the '|| 1' - when read_balance prefers
586 * non-congested targets, it can be removed
587 */
588 if ((bits & (1<<BDI_async_congested)) || 1)
589 ret |= bdi_congested(&q->backing_dev_info, bits);
590 else
591 ret &= bdi_congested(&q->backing_dev_info, bits);
592 }
593 }
594 rcu_read_unlock();
595 return ret;
596 }
597
598
599 static int flush_pending_writes(conf_t *conf)
600 {
601 /* Any writes that have been queued but are awaiting
602 * bitmap updates get flushed here.
603 * We return 1 if any requests were actually submitted.
604 */
605 int rv = 0;
606
607 spin_lock_irq(&conf->device_lock);
608
609 if (conf->pending_bio_list.head) {
610 struct bio *bio;
611 bio = bio_list_get(&conf->pending_bio_list);
612 blk_remove_plug(conf->mddev->queue);
613 spin_unlock_irq(&conf->device_lock);
614 /* flush any pending bitmap writes to
615 * disk before proceeding w/ I/O */
616 bitmap_unplug(conf->mddev->bitmap);
617
618 while (bio) { /* submit pending writes */
619 struct bio *next = bio->bi_next;
620 bio->bi_next = NULL;
621 generic_make_request(bio);
622 bio = next;
623 }
624 rv = 1;
625 } else
626 spin_unlock_irq(&conf->device_lock);
627 return rv;
628 }
629
630 /* Barriers....
631 * Sometimes we need to suspend IO while we do something else,
632 * either some resync/recovery, or reconfigure the array.
633 * To do this we raise a 'barrier'.
634 * The 'barrier' is a counter that can be raised multiple times
635 * to count how many activities are happening which preclude
636 * normal IO.
637 * We can only raise the barrier if there is no pending IO.
638 * i.e. if nr_pending == 0.
639 * We choose only to raise the barrier if no-one is waiting for the
640 * barrier to go down. This means that as soon as an IO request
641 * is ready, no other operations which require a barrier will start
642 * until the IO request has had a chance.
643 *
644 * So: regular IO calls 'wait_barrier'. When that returns there
645 * is no backgroup IO happening, It must arrange to call
646 * allow_barrier when it has finished its IO.
647 * backgroup IO calls must call raise_barrier. Once that returns
648 * there is no normal IO happeing. It must arrange to call
649 * lower_barrier when the particular background IO completes.
650 */
651 #define RESYNC_DEPTH 32
652
653 static void raise_barrier(conf_t *conf)
654 {
655 spin_lock_irq(&conf->resync_lock);
656
657 /* Wait until no block IO is waiting */
658 wait_event_lock_irq(conf->wait_barrier, !conf->nr_waiting,
659 conf->resync_lock,
660 raid1_unplug(conf->mddev->queue));
661
662 /* block any new IO from starting */
663 conf->barrier++;
664
665 /* No wait for all pending IO to complete */
666 wait_event_lock_irq(conf->wait_barrier,
667 !conf->nr_pending && conf->barrier < RESYNC_DEPTH,
668 conf->resync_lock,
669 raid1_unplug(conf->mddev->queue));
670
671 spin_unlock_irq(&conf->resync_lock);
672 }
673
674 static void lower_barrier(conf_t *conf)
675 {
676 unsigned long flags;
677 spin_lock_irqsave(&conf->resync_lock, flags);
678 conf->barrier--;
679 spin_unlock_irqrestore(&conf->resync_lock, flags);
680 wake_up(&conf->wait_barrier);
681 }
682
683 static void wait_barrier(conf_t *conf)
684 {
685 spin_lock_irq(&conf->resync_lock);
686 if (conf->barrier) {
687 conf->nr_waiting++;
688 wait_event_lock_irq(conf->wait_barrier, !conf->barrier,
689 conf->resync_lock,
690 raid1_unplug(conf->mddev->queue));
691 conf->nr_waiting--;
692 }
693 conf->nr_pending++;
694 spin_unlock_irq(&conf->resync_lock);
695 }
696
697 static void allow_barrier(conf_t *conf)
698 {
699 unsigned long flags;
700 spin_lock_irqsave(&conf->resync_lock, flags);
701 conf->nr_pending--;
702 spin_unlock_irqrestore(&conf->resync_lock, flags);
703 wake_up(&conf->wait_barrier);
704 }
705
706 static void freeze_array(conf_t *conf)
707 {
708 /* stop syncio and normal IO and wait for everything to
709 * go quite.
710 * We increment barrier and nr_waiting, and then
711 * wait until nr_pending match nr_queued+1
712 * This is called in the context of one normal IO request
713 * that has failed. Thus any sync request that might be pending
714 * will be blocked by nr_pending, and we need to wait for
715 * pending IO requests to complete or be queued for re-try.
716 * Thus the number queued (nr_queued) plus this request (1)
717 * must match the number of pending IOs (nr_pending) before
718 * we continue.
719 */
720 spin_lock_irq(&conf->resync_lock);
721 conf->barrier++;
722 conf->nr_waiting++;
723 wait_event_lock_irq(conf->wait_barrier,
724 conf->nr_pending == conf->nr_queued+1,
725 conf->resync_lock,
726 ({ flush_pending_writes(conf);
727 raid1_unplug(conf->mddev->queue); }));
728 spin_unlock_irq(&conf->resync_lock);
729 }
730 static void unfreeze_array(conf_t *conf)
731 {
732 /* reverse the effect of the freeze */
733 spin_lock_irq(&conf->resync_lock);
734 conf->barrier--;
735 conf->nr_waiting--;
736 wake_up(&conf->wait_barrier);
737 spin_unlock_irq(&conf->resync_lock);
738 }
739
740
741 /* duplicate the data pages for behind I/O */
742 static struct page **alloc_behind_pages(struct bio *bio)
743 {
744 int i;
745 struct bio_vec *bvec;
746 struct page **pages = kzalloc(bio->bi_vcnt * sizeof(struct page *),
747 GFP_NOIO);
748 if (unlikely(!pages))
749 goto do_sync_io;
750
751 bio_for_each_segment(bvec, bio, i) {
752 pages[i] = alloc_page(GFP_NOIO);
753 if (unlikely(!pages[i]))
754 goto do_sync_io;
755 memcpy(kmap(pages[i]) + bvec->bv_offset,
756 kmap(bvec->bv_page) + bvec->bv_offset, bvec->bv_len);
757 kunmap(pages[i]);
758 kunmap(bvec->bv_page);
759 }
760
761 return pages;
762
763 do_sync_io:
764 if (pages)
765 for (i = 0; i < bio->bi_vcnt && pages[i]; i++)
766 put_page(pages[i]);
767 kfree(pages);
768 PRINTK("%dB behind alloc failed, doing sync I/O\n", bio->bi_size);
769 return NULL;
770 }
771
772 static int make_request(struct request_queue *q, struct bio * bio)
773 {
774 mddev_t *mddev = q->queuedata;
775 conf_t *conf = mddev->private;
776 mirror_info_t *mirror;
777 r1bio_t *r1_bio;
778 struct bio *read_bio;
779 int i, targets = 0, disks;
780 struct bitmap *bitmap;
781 unsigned long flags;
782 struct bio_list bl;
783 struct page **behind_pages = NULL;
784 const int rw = bio_data_dir(bio);
785 const int do_sync = bio_sync(bio);
786 int cpu, do_barriers;
787 mdk_rdev_t *blocked_rdev;
788
789 /*
790 * Register the new request and wait if the reconstruction
791 * thread has put up a bar for new requests.
792 * Continue immediately if no resync is active currently.
793 * We test barriers_work *after* md_write_start as md_write_start
794 * may cause the first superblock write, and that will check out
795 * if barriers work.
796 */
797
798 md_write_start(mddev, bio); /* wait on superblock update early */
799
800 if (unlikely(!mddev->barriers_work && bio_barrier(bio))) {
801 if (rw == WRITE)
802 md_write_end(mddev);
803 bio_endio(bio, -EOPNOTSUPP);
804 return 0;
805 }
806
807 wait_barrier(conf);
808
809 bitmap = mddev->bitmap;
810
811 cpu = part_stat_lock();
812 part_stat_inc(cpu, &mddev->gendisk->part0, ios[rw]);
813 part_stat_add(cpu, &mddev->gendisk->part0, sectors[rw],
814 bio_sectors(bio));
815 part_stat_unlock();
816
817 /*
818 * make_request() can abort the operation when READA is being
819 * used and no empty request is available.
820 *
821 */
822 r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
823
824 r1_bio->master_bio = bio;
825 r1_bio->sectors = bio->bi_size >> 9;
826 r1_bio->state = 0;
827 r1_bio->mddev = mddev;
828 r1_bio->sector = bio->bi_sector;
829
830 if (rw == READ) {
831 /*
832 * read balancing logic:
833 */
834 int rdisk = read_balance(conf, r1_bio);
835
836 if (rdisk < 0) {
837 /* couldn't find anywhere to read from */
838 raid_end_bio_io(r1_bio);
839 return 0;
840 }
841 mirror = conf->mirrors + rdisk;
842
843 r1_bio->read_disk = rdisk;
844
845 read_bio = bio_clone(bio, GFP_NOIO);
846
847 r1_bio->bios[rdisk] = read_bio;
848
849 read_bio->bi_sector = r1_bio->sector + mirror->rdev->data_offset;
850 read_bio->bi_bdev = mirror->rdev->bdev;
851 read_bio->bi_end_io = raid1_end_read_request;
852 read_bio->bi_rw = READ | do_sync;
853 read_bio->bi_private = r1_bio;
854
855 generic_make_request(read_bio);
856 return 0;
857 }
858
859 /*
860 * WRITE:
861 */
862 /* first select target devices under spinlock and
863 * inc refcount on their rdev. Record them by setting
864 * bios[x] to bio
865 */
866 disks = conf->raid_disks;
867 #if 0
868 { static int first=1;
869 if (first) printk("First Write sector %llu disks %d\n",
870 (unsigned long long)r1_bio->sector, disks);
871 first = 0;
872 }
873 #endif
874 retry_write:
875 blocked_rdev = NULL;
876 rcu_read_lock();
877 for (i = 0; i < disks; i++) {
878 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
879 if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) {
880 atomic_inc(&rdev->nr_pending);
881 blocked_rdev = rdev;
882 break;
883 }
884 if (rdev && !test_bit(Faulty, &rdev->flags)) {
885 atomic_inc(&rdev->nr_pending);
886 if (test_bit(Faulty, &rdev->flags)) {
887 rdev_dec_pending(rdev, mddev);
888 r1_bio->bios[i] = NULL;
889 } else
890 r1_bio->bios[i] = bio;
891 targets++;
892 } else
893 r1_bio->bios[i] = NULL;
894 }
895 rcu_read_unlock();
896
897 if (unlikely(blocked_rdev)) {
898 /* Wait for this device to become unblocked */
899 int j;
900
901 for (j = 0; j < i; j++)
902 if (r1_bio->bios[j])
903 rdev_dec_pending(conf->mirrors[j].rdev, mddev);
904
905 allow_barrier(conf);
906 md_wait_for_blocked_rdev(blocked_rdev, mddev);
907 wait_barrier(conf);
908 goto retry_write;
909 }
910
911 BUG_ON(targets == 0); /* we never fail the last device */
912
913 if (targets < conf->raid_disks) {
914 /* array is degraded, we will not clear the bitmap
915 * on I/O completion (see raid1_end_write_request) */
916 set_bit(R1BIO_Degraded, &r1_bio->state);
917 }
918
919 /* do behind I/O ? */
920 if (bitmap &&
921 atomic_read(&bitmap->behind_writes) < bitmap->max_write_behind &&
922 (behind_pages = alloc_behind_pages(bio)) != NULL)
923 set_bit(R1BIO_BehindIO, &r1_bio->state);
924
925 atomic_set(&r1_bio->remaining, 0);
926 atomic_set(&r1_bio->behind_remaining, 0);
927
928 do_barriers = bio_barrier(bio);
929 if (do_barriers)
930 set_bit(R1BIO_Barrier, &r1_bio->state);
931
932 bio_list_init(&bl);
933 for (i = 0; i < disks; i++) {
934 struct bio *mbio;
935 if (!r1_bio->bios[i])
936 continue;
937
938 mbio = bio_clone(bio, GFP_NOIO);
939 r1_bio->bios[i] = mbio;
940
941 mbio->bi_sector = r1_bio->sector + conf->mirrors[i].rdev->data_offset;
942 mbio->bi_bdev = conf->mirrors[i].rdev->bdev;
943 mbio->bi_end_io = raid1_end_write_request;
944 mbio->bi_rw = WRITE | do_barriers | do_sync;
945 mbio->bi_private = r1_bio;
946
947 if (behind_pages) {
948 struct bio_vec *bvec;
949 int j;
950
951 /* Yes, I really want the '__' version so that
952 * we clear any unused pointer in the io_vec, rather
953 * than leave them unchanged. This is important
954 * because when we come to free the pages, we won't
955 * know the originial bi_idx, so we just free
956 * them all
957 */
958 __bio_for_each_segment(bvec, mbio, j, 0)
959 bvec->bv_page = behind_pages[j];
960 if (test_bit(WriteMostly, &conf->mirrors[i].rdev->flags))
961 atomic_inc(&r1_bio->behind_remaining);
962 }
963
964 atomic_inc(&r1_bio->remaining);
965
966 bio_list_add(&bl, mbio);
967 }
968 kfree(behind_pages); /* the behind pages are attached to the bios now */
969
970 bitmap_startwrite(bitmap, bio->bi_sector, r1_bio->sectors,
971 test_bit(R1BIO_BehindIO, &r1_bio->state));
972 spin_lock_irqsave(&conf->device_lock, flags);
973 bio_list_merge(&conf->pending_bio_list, &bl);
974 bio_list_init(&bl);
975
976 blk_plug_device(mddev->queue);
977 spin_unlock_irqrestore(&conf->device_lock, flags);
978
979 /* In case raid1d snuck into freeze_array */
980 wake_up(&conf->wait_barrier);
981
982 if (do_sync)
983 md_wakeup_thread(mddev->thread);
984 #if 0
985 while ((bio = bio_list_pop(&bl)) != NULL)
986 generic_make_request(bio);
987 #endif
988
989 return 0;
990 }
991
992 static void status(struct seq_file *seq, mddev_t *mddev)
993 {
994 conf_t *conf = mddev->private;
995 int i;
996
997 seq_printf(seq, " [%d/%d] [", conf->raid_disks,
998 conf->raid_disks - mddev->degraded);
999 rcu_read_lock();
1000 for (i = 0; i < conf->raid_disks; i++) {
1001 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
1002 seq_printf(seq, "%s",
1003 rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_");
1004 }
1005 rcu_read_unlock();
1006 seq_printf(seq, "]");
1007 }
1008
1009
1010 static void error(mddev_t *mddev, mdk_rdev_t *rdev)
1011 {
1012 char b[BDEVNAME_SIZE];
1013 conf_t *conf = mddev->private;
1014
1015 /*
1016 * If it is not operational, then we have already marked it as dead
1017 * else if it is the last working disks, ignore the error, let the
1018 * next level up know.
1019 * else mark the drive as failed
1020 */
1021 if (test_bit(In_sync, &rdev->flags)
1022 && (conf->raid_disks - mddev->degraded) == 1) {
1023 /*
1024 * Don't fail the drive, act as though we were just a
1025 * normal single drive.
1026 * However don't try a recovery from this drive as
1027 * it is very likely to fail.
1028 */
1029 mddev->recovery_disabled = 1;
1030 return;
1031 }
1032 if (test_and_clear_bit(In_sync, &rdev->flags)) {
1033 unsigned long flags;
1034 spin_lock_irqsave(&conf->device_lock, flags);
1035 mddev->degraded++;
1036 set_bit(Faulty, &rdev->flags);
1037 spin_unlock_irqrestore(&conf->device_lock, flags);
1038 /*
1039 * if recovery is running, make sure it aborts.
1040 */
1041 set_bit(MD_RECOVERY_INTR, &mddev->recovery);
1042 } else
1043 set_bit(Faulty, &rdev->flags);
1044 set_bit(MD_CHANGE_DEVS, &mddev->flags);
1045 printk(KERN_ALERT "raid1: Disk failure on %s, disabling device.\n"
1046 "raid1: Operation continuing on %d devices.\n",
1047 bdevname(rdev->bdev,b), conf->raid_disks - mddev->degraded);
1048 }
1049
1050 static void print_conf(conf_t *conf)
1051 {
1052 int i;
1053
1054 printk("RAID1 conf printout:\n");
1055 if (!conf) {
1056 printk("(!conf)\n");
1057 return;
1058 }
1059 printk(" --- wd:%d rd:%d\n", conf->raid_disks - conf->mddev->degraded,
1060 conf->raid_disks);
1061
1062 rcu_read_lock();
1063 for (i = 0; i < conf->raid_disks; i++) {
1064 char b[BDEVNAME_SIZE];
1065 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
1066 if (rdev)
1067 printk(" disk %d, wo:%d, o:%d, dev:%s\n",
1068 i, !test_bit(In_sync, &rdev->flags),
1069 !test_bit(Faulty, &rdev->flags),
1070 bdevname(rdev->bdev,b));
1071 }
1072 rcu_read_unlock();
1073 }
1074
1075 static void close_sync(conf_t *conf)
1076 {
1077 wait_barrier(conf);
1078 allow_barrier(conf);
1079
1080 mempool_destroy(conf->r1buf_pool);
1081 conf->r1buf_pool = NULL;
1082 }
1083
1084 static int raid1_spare_active(mddev_t *mddev)
1085 {
1086 int i;
1087 conf_t *conf = mddev->private;
1088
1089 /*
1090 * Find all failed disks within the RAID1 configuration
1091 * and mark them readable.
1092 * Called under mddev lock, so rcu protection not needed.
1093 */
1094 for (i = 0; i < conf->raid_disks; i++) {
1095 mdk_rdev_t *rdev = conf->mirrors[i].rdev;
1096 if (rdev
1097 && !test_bit(Faulty, &rdev->flags)
1098 && !test_and_set_bit(In_sync, &rdev->flags)) {
1099 unsigned long flags;
1100 spin_lock_irqsave(&conf->device_lock, flags);
1101 mddev->degraded--;
1102 spin_unlock_irqrestore(&conf->device_lock, flags);
1103 }
1104 }
1105
1106 print_conf(conf);
1107 return 0;
1108 }
1109
1110
1111 static int raid1_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
1112 {
1113 conf_t *conf = mddev->private;
1114 int err = -EEXIST;
1115 int mirror = 0;
1116 mirror_info_t *p;
1117 int first = 0;
1118 int last = mddev->raid_disks - 1;
1119
1120 if (rdev->raid_disk >= 0)
1121 first = last = rdev->raid_disk;
1122
1123 for (mirror = first; mirror <= last; mirror++)
1124 if ( !(p=conf->mirrors+mirror)->rdev) {
1125
1126 disk_stack_limits(mddev->gendisk, rdev->bdev,
1127 rdev->data_offset << 9);
1128 /* as we don't honour merge_bvec_fn, we must never risk
1129 * violating it, so limit ->max_sector to one PAGE, as
1130 * a one page request is never in violation.
1131 */
1132 if (rdev->bdev->bd_disk->queue->merge_bvec_fn &&
1133 queue_max_sectors(mddev->queue) > (PAGE_SIZE>>9))
1134 blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9);
1135
1136 p->head_position = 0;
1137 rdev->raid_disk = mirror;
1138 err = 0;
1139 /* As all devices are equivalent, we don't need a full recovery
1140 * if this was recently any drive of the array
1141 */
1142 if (rdev->saved_raid_disk < 0)
1143 conf->fullsync = 1;
1144 rcu_assign_pointer(p->rdev, rdev);
1145 break;
1146 }
1147 md_integrity_add_rdev(rdev, mddev);
1148 print_conf(conf);
1149 return err;
1150 }
1151
1152 static int raid1_remove_disk(mddev_t *mddev, int number)
1153 {
1154 conf_t *conf = mddev->private;
1155 int err = 0;
1156 mdk_rdev_t *rdev;
1157 mirror_info_t *p = conf->mirrors+ number;
1158
1159 print_conf(conf);
1160 rdev = p->rdev;
1161 if (rdev) {
1162 if (test_bit(In_sync, &rdev->flags) ||
1163 atomic_read(&rdev->nr_pending)) {
1164 err = -EBUSY;
1165 goto abort;
1166 }
1167 /* Only remove non-faulty devices is recovery
1168 * is not possible.
1169 */
1170 if (!test_bit(Faulty, &rdev->flags) &&
1171 mddev->degraded < conf->raid_disks) {
1172 err = -EBUSY;
1173 goto abort;
1174 }
1175 p->rdev = NULL;
1176 synchronize_rcu();
1177 if (atomic_read(&rdev->nr_pending)) {
1178 /* lost the race, try later */
1179 err = -EBUSY;
1180 p->rdev = rdev;
1181 goto abort;
1182 }
1183 md_integrity_register(mddev);
1184 }
1185 abort:
1186
1187 print_conf(conf);
1188 return err;
1189 }
1190
1191
1192 static void end_sync_read(struct bio *bio, int error)
1193 {
1194 r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private);
1195 int i;
1196
1197 for (i=r1_bio->mddev->raid_disks; i--; )
1198 if (r1_bio->bios[i] == bio)
1199 break;
1200 BUG_ON(i < 0);
1201 update_head_pos(i, r1_bio);
1202 /*
1203 * we have read a block, now it needs to be re-written,
1204 * or re-read if the read failed.
1205 * We don't do much here, just schedule handling by raid1d
1206 */
1207 if (test_bit(BIO_UPTODATE, &bio->bi_flags))
1208 set_bit(R1BIO_Uptodate, &r1_bio->state);
1209
1210 if (atomic_dec_and_test(&r1_bio->remaining))
1211 reschedule_retry(r1_bio);
1212 }
1213
1214 static void end_sync_write(struct bio *bio, int error)
1215 {
1216 int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
1217 r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private);
1218 mddev_t *mddev = r1_bio->mddev;
1219 conf_t *conf = mddev->private;
1220 int i;
1221 int mirror=0;
1222
1223 for (i = 0; i < conf->raid_disks; i++)
1224 if (r1_bio->bios[i] == bio) {
1225 mirror = i;
1226 break;
1227 }
1228 if (!uptodate) {
1229 int sync_blocks = 0;
1230 sector_t s = r1_bio->sector;
1231 long sectors_to_go = r1_bio->sectors;
1232 /* make sure these bits doesn't get cleared. */
1233 do {
1234 bitmap_end_sync(mddev->bitmap, s,
1235 &sync_blocks, 1);
1236 s += sync_blocks;
1237 sectors_to_go -= sync_blocks;
1238 } while (sectors_to_go > 0);
1239 md_error(mddev, conf->mirrors[mirror].rdev);
1240 }
1241
1242 update_head_pos(mirror, r1_bio);
1243
1244 if (atomic_dec_and_test(&r1_bio->remaining)) {
1245 sector_t s = r1_bio->sectors;
1246 put_buf(r1_bio);
1247 md_done_sync(mddev, s, uptodate);
1248 }
1249 }
1250
1251 static void sync_request_write(mddev_t *mddev, r1bio_t *r1_bio)
1252 {
1253 conf_t *conf = mddev->private;
1254 int i;
1255 int disks = conf->raid_disks;
1256 struct bio *bio, *wbio;
1257
1258 bio = r1_bio->bios[r1_bio->read_disk];
1259
1260
1261 if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
1262 /* We have read all readable devices. If we haven't
1263 * got the block, then there is no hope left.
1264 * If we have, then we want to do a comparison
1265 * and skip the write if everything is the same.
1266 * If any blocks failed to read, then we need to
1267 * attempt an over-write
1268 */
1269 int primary;
1270 if (!test_bit(R1BIO_Uptodate, &r1_bio->state)) {
1271 for (i=0; i<mddev->raid_disks; i++)
1272 if (r1_bio->bios[i]->bi_end_io == end_sync_read)
1273 md_error(mddev, conf->mirrors[i].rdev);
1274
1275 md_done_sync(mddev, r1_bio->sectors, 1);
1276 put_buf(r1_bio);
1277 return;
1278 }
1279 for (primary=0; primary<mddev->raid_disks; primary++)
1280 if (r1_bio->bios[primary]->bi_end_io == end_sync_read &&
1281 test_bit(BIO_UPTODATE, &r1_bio->bios[primary]->bi_flags)) {
1282 r1_bio->bios[primary]->bi_end_io = NULL;
1283 rdev_dec_pending(conf->mirrors[primary].rdev, mddev);
1284 break;
1285 }
1286 r1_bio->read_disk = primary;
1287 for (i=0; i<mddev->raid_disks; i++)
1288 if (r1_bio->bios[i]->bi_end_io == end_sync_read) {
1289 int j;
1290 int vcnt = r1_bio->sectors >> (PAGE_SHIFT- 9);
1291 struct bio *pbio = r1_bio->bios[primary];
1292 struct bio *sbio = r1_bio->bios[i];
1293
1294 if (test_bit(BIO_UPTODATE, &sbio->bi_flags)) {
1295 for (j = vcnt; j-- ; ) {
1296 struct page *p, *s;
1297 p = pbio->bi_io_vec[j].bv_page;
1298 s = sbio->bi_io_vec[j].bv_page;
1299 if (memcmp(page_address(p),
1300 page_address(s),
1301 PAGE_SIZE))
1302 break;
1303 }
1304 } else
1305 j = 0;
1306 if (j >= 0)
1307 mddev->resync_mismatches += r1_bio->sectors;
1308 if (j < 0 || (test_bit(MD_RECOVERY_CHECK, &mddev->recovery)
1309 && test_bit(BIO_UPTODATE, &sbio->bi_flags))) {
1310 sbio->bi_end_io = NULL;
1311 rdev_dec_pending(conf->mirrors[i].rdev, mddev);
1312 } else {
1313 /* fixup the bio for reuse */
1314 int size;
1315 sbio->bi_vcnt = vcnt;
1316 sbio->bi_size = r1_bio->sectors << 9;
1317 sbio->bi_idx = 0;
1318 sbio->bi_phys_segments = 0;
1319 sbio->bi_flags &= ~(BIO_POOL_MASK - 1);
1320 sbio->bi_flags |= 1 << BIO_UPTODATE;
1321 sbio->bi_next = NULL;
1322 sbio->bi_sector = r1_bio->sector +
1323 conf->mirrors[i].rdev->data_offset;
1324 sbio->bi_bdev = conf->mirrors[i].rdev->bdev;
1325 size = sbio->bi_size;
1326 for (j = 0; j < vcnt ; j++) {
1327 struct bio_vec *bi;
1328 bi = &sbio->bi_io_vec[j];
1329 bi->bv_offset = 0;
1330 if (size > PAGE_SIZE)
1331 bi->bv_len = PAGE_SIZE;
1332 else
1333 bi->bv_len = size;
1334 size -= PAGE_SIZE;
1335 memcpy(page_address(bi->bv_page),
1336 page_address(pbio->bi_io_vec[j].bv_page),
1337 PAGE_SIZE);
1338 }
1339
1340 }
1341 }
1342 }
1343 if (!test_bit(R1BIO_Uptodate, &r1_bio->state)) {
1344 /* ouch - failed to read all of that.
1345 * Try some synchronous reads of other devices to get
1346 * good data, much like with normal read errors. Only
1347 * read into the pages we already have so we don't
1348 * need to re-issue the read request.
1349 * We don't need to freeze the array, because being in an
1350 * active sync request, there is no normal IO, and
1351 * no overlapping syncs.
1352 */
1353 sector_t sect = r1_bio->sector;
1354 int sectors = r1_bio->sectors;
1355 int idx = 0;
1356
1357 while(sectors) {
1358 int s = sectors;
1359 int d = r1_bio->read_disk;
1360 int success = 0;
1361 mdk_rdev_t *rdev;
1362
1363 if (s > (PAGE_SIZE>>9))
1364 s = PAGE_SIZE >> 9;
1365 do {
1366 if (r1_bio->bios[d]->bi_end_io == end_sync_read) {
1367 /* No rcu protection needed here devices
1368 * can only be removed when no resync is
1369 * active, and resync is currently active
1370 */
1371 rdev = conf->mirrors[d].rdev;
1372 if (sync_page_io(rdev->bdev,
1373 sect + rdev->data_offset,
1374 s<<9,
1375 bio->bi_io_vec[idx].bv_page,
1376 READ)) {
1377 success = 1;
1378 break;
1379 }
1380 }
1381 d++;
1382 if (d == conf->raid_disks)
1383 d = 0;
1384 } while (!success && d != r1_bio->read_disk);
1385
1386 if (success) {
1387 int start = d;
1388 /* write it back and re-read */
1389 set_bit(R1BIO_Uptodate, &r1_bio->state);
1390 while (d != r1_bio->read_disk) {
1391 if (d == 0)
1392 d = conf->raid_disks;
1393 d--;
1394 if (r1_bio->bios[d]->bi_end_io != end_sync_read)
1395 continue;
1396 rdev = conf->mirrors[d].rdev;
1397 atomic_add(s, &rdev->corrected_errors);
1398 if (sync_page_io(rdev->bdev,
1399 sect + rdev->data_offset,
1400 s<<9,
1401 bio->bi_io_vec[idx].bv_page,
1402 WRITE) == 0)
1403 md_error(mddev, rdev);
1404 }
1405 d = start;
1406 while (d != r1_bio->read_disk) {
1407 if (d == 0)
1408 d = conf->raid_disks;
1409 d--;
1410 if (r1_bio->bios[d]->bi_end_io != end_sync_read)
1411 continue;
1412 rdev = conf->mirrors[d].rdev;
1413 if (sync_page_io(rdev->bdev,
1414 sect + rdev->data_offset,
1415 s<<9,
1416 bio->bi_io_vec[idx].bv_page,
1417 READ) == 0)
1418 md_error(mddev, rdev);
1419 }
1420 } else {
1421 char b[BDEVNAME_SIZE];
1422 /* Cannot read from anywhere, array is toast */
1423 md_error(mddev, conf->mirrors[r1_bio->read_disk].rdev);
1424 printk(KERN_ALERT "raid1: %s: unrecoverable I/O read error"
1425 " for block %llu\n",
1426 bdevname(bio->bi_bdev,b),
1427 (unsigned long long)r1_bio->sector);
1428 md_done_sync(mddev, r1_bio->sectors, 0);
1429 put_buf(r1_bio);
1430 return;
1431 }
1432 sectors -= s;
1433 sect += s;
1434 idx ++;
1435 }
1436 }
1437
1438 /*
1439 * schedule writes
1440 */
1441 atomic_set(&r1_bio->remaining, 1);
1442 for (i = 0; i < disks ; i++) {
1443 wbio = r1_bio->bios[i];
1444 if (wbio->bi_end_io == NULL ||
1445 (wbio->bi_end_io == end_sync_read &&
1446 (i == r1_bio->read_disk ||
1447 !test_bit(MD_RECOVERY_SYNC, &mddev->recovery))))
1448 continue;
1449
1450 wbio->bi_rw = WRITE;
1451 wbio->bi_end_io = end_sync_write;
1452 atomic_inc(&r1_bio->remaining);
1453 md_sync_acct(conf->mirrors[i].rdev->bdev, wbio->bi_size >> 9);
1454
1455 generic_make_request(wbio);
1456 }
1457
1458 if (atomic_dec_and_test(&r1_bio->remaining)) {
1459 /* if we're here, all write(s) have completed, so clean up */
1460 md_done_sync(mddev, r1_bio->sectors, 1);
1461 put_buf(r1_bio);
1462 }
1463 }
1464
1465 /*
1466 * This is a kernel thread which:
1467 *
1468 * 1. Retries failed read operations on working mirrors.
1469 * 2. Updates the raid superblock when problems encounter.
1470 * 3. Performs writes following reads for array syncronising.
1471 */
1472
1473 static void fix_read_error(conf_t *conf, int read_disk,
1474 sector_t sect, int sectors)
1475 {
1476 mddev_t *mddev = conf->mddev;
1477 while(sectors) {
1478 int s = sectors;
1479 int d = read_disk;
1480 int success = 0;
1481 int start;
1482 mdk_rdev_t *rdev;
1483
1484 if (s > (PAGE_SIZE>>9))
1485 s = PAGE_SIZE >> 9;
1486
1487 do {
1488 /* Note: no rcu protection needed here
1489 * as this is synchronous in the raid1d thread
1490 * which is the thread that might remove
1491 * a device. If raid1d ever becomes multi-threaded....
1492 */
1493 rdev = conf->mirrors[d].rdev;
1494 if (rdev &&
1495 test_bit(In_sync, &rdev->flags) &&
1496 sync_page_io(rdev->bdev,
1497 sect + rdev->data_offset,
1498 s<<9,
1499 conf->tmppage, READ))
1500 success = 1;
1501 else {
1502 d++;
1503 if (d == conf->raid_disks)
1504 d = 0;
1505 }
1506 } while (!success && d != read_disk);
1507
1508 if (!success) {
1509 /* Cannot read from anywhere -- bye bye array */
1510 md_error(mddev, conf->mirrors[read_disk].rdev);
1511 break;
1512 }
1513 /* write it back and re-read */
1514 start = d;
1515 while (d != read_disk) {
1516 if (d==0)
1517 d = conf->raid_disks;
1518 d--;
1519 rdev = conf->mirrors[d].rdev;
1520 if (rdev &&
1521 test_bit(In_sync, &rdev->flags)) {
1522 if (sync_page_io(rdev->bdev,
1523 sect + rdev->data_offset,
1524 s<<9, conf->tmppage, WRITE)
1525 == 0)
1526 /* Well, this device is dead */
1527 md_error(mddev, rdev);
1528 }
1529 }
1530 d = start;
1531 while (d != read_disk) {
1532 char b[BDEVNAME_SIZE];
1533 if (d==0)
1534 d = conf->raid_disks;
1535 d--;
1536 rdev = conf->mirrors[d].rdev;
1537 if (rdev &&
1538 test_bit(In_sync, &rdev->flags)) {
1539 if (sync_page_io(rdev->bdev,
1540 sect + rdev->data_offset,
1541 s<<9, conf->tmppage, READ)
1542 == 0)
1543 /* Well, this device is dead */
1544 md_error(mddev, rdev);
1545 else {
1546 atomic_add(s, &rdev->corrected_errors);
1547 printk(KERN_INFO
1548 "raid1:%s: read error corrected "
1549 "(%d sectors at %llu on %s)\n",
1550 mdname(mddev), s,
1551 (unsigned long long)(sect +
1552 rdev->data_offset),
1553 bdevname(rdev->bdev, b));
1554 }
1555 }
1556 }
1557 sectors -= s;
1558 sect += s;
1559 }
1560 }
1561
1562 static void raid1d(mddev_t *mddev)
1563 {
1564 r1bio_t *r1_bio;
1565 struct bio *bio;
1566 unsigned long flags;
1567 conf_t *conf = mddev->private;
1568 struct list_head *head = &conf->retry_list;
1569 int unplug=0;
1570 mdk_rdev_t *rdev;
1571
1572 md_check_recovery(mddev);
1573
1574 for (;;) {
1575 char b[BDEVNAME_SIZE];
1576
1577 unplug += flush_pending_writes(conf);
1578
1579 spin_lock_irqsave(&conf->device_lock, flags);
1580 if (list_empty(head)) {
1581 spin_unlock_irqrestore(&conf->device_lock, flags);
1582 break;
1583 }
1584 r1_bio = list_entry(head->prev, r1bio_t, retry_list);
1585 list_del(head->prev);
1586 conf->nr_queued--;
1587 spin_unlock_irqrestore(&conf->device_lock, flags);
1588
1589 mddev = r1_bio->mddev;
1590 conf = mddev->private;
1591 if (test_bit(R1BIO_IsSync, &r1_bio->state)) {
1592 sync_request_write(mddev, r1_bio);
1593 unplug = 1;
1594 } else if (test_bit(R1BIO_BarrierRetry, &r1_bio->state)) {
1595 /* some requests in the r1bio were BIO_RW_BARRIER
1596 * requests which failed with -EOPNOTSUPP. Hohumm..
1597 * Better resubmit without the barrier.
1598 * We know which devices to resubmit for, because
1599 * all others have had their bios[] entry cleared.
1600 * We already have a nr_pending reference on these rdevs.
1601 */
1602 int i;
1603 const int do_sync = bio_sync(r1_bio->master_bio);
1604 clear_bit(R1BIO_BarrierRetry, &r1_bio->state);
1605 clear_bit(R1BIO_Barrier, &r1_bio->state);
1606 for (i=0; i < conf->raid_disks; i++)
1607 if (r1_bio->bios[i])
1608 atomic_inc(&r1_bio->remaining);
1609 for (i=0; i < conf->raid_disks; i++)
1610 if (r1_bio->bios[i]) {
1611 struct bio_vec *bvec;
1612 int j;
1613
1614 bio = bio_clone(r1_bio->master_bio, GFP_NOIO);
1615 /* copy pages from the failed bio, as
1616 * this might be a write-behind device */
1617 __bio_for_each_segment(bvec, bio, j, 0)
1618 bvec->bv_page = bio_iovec_idx(r1_bio->bios[i], j)->bv_page;
1619 bio_put(r1_bio->bios[i]);
1620 bio->bi_sector = r1_bio->sector +
1621 conf->mirrors[i].rdev->data_offset;
1622 bio->bi_bdev = conf->mirrors[i].rdev->bdev;
1623 bio->bi_end_io = raid1_end_write_request;
1624 bio->bi_rw = WRITE | do_sync;
1625 bio->bi_private = r1_bio;
1626 r1_bio->bios[i] = bio;
1627 generic_make_request(bio);
1628 }
1629 } else {
1630 int disk;
1631
1632 /* we got a read error. Maybe the drive is bad. Maybe just
1633 * the block and we can fix it.
1634 * We freeze all other IO, and try reading the block from
1635 * other devices. When we find one, we re-write
1636 * and check it that fixes the read error.
1637 * This is all done synchronously while the array is
1638 * frozen
1639 */
1640 if (mddev->ro == 0) {
1641 freeze_array(conf);
1642 fix_read_error(conf, r1_bio->read_disk,
1643 r1_bio->sector,
1644 r1_bio->sectors);
1645 unfreeze_array(conf);
1646 } else
1647 md_error(mddev,
1648 conf->mirrors[r1_bio->read_disk].rdev);
1649
1650 bio = r1_bio->bios[r1_bio->read_disk];
1651 if ((disk=read_balance(conf, r1_bio)) == -1) {
1652 printk(KERN_ALERT "raid1: %s: unrecoverable I/O"
1653 " read error for block %llu\n",
1654 bdevname(bio->bi_bdev,b),
1655 (unsigned long long)r1_bio->sector);
1656 raid_end_bio_io(r1_bio);
1657 } else {
1658 const int do_sync = bio_sync(r1_bio->master_bio);
1659 r1_bio->bios[r1_bio->read_disk] =
1660 mddev->ro ? IO_BLOCKED : NULL;
1661 r1_bio->read_disk = disk;
1662 bio_put(bio);
1663 bio = bio_clone(r1_bio->master_bio, GFP_NOIO);
1664 r1_bio->bios[r1_bio->read_disk] = bio;
1665 rdev = conf->mirrors[disk].rdev;
1666 if (printk_ratelimit())
1667 printk(KERN_ERR "raid1: %s: redirecting sector %llu to"
1668 " another mirror\n",
1669 bdevname(rdev->bdev,b),
1670 (unsigned long long)r1_bio->sector);
1671 bio->bi_sector = r1_bio->sector + rdev->data_offset;
1672 bio->bi_bdev = rdev->bdev;
1673 bio->bi_end_io = raid1_end_read_request;
1674 bio->bi_rw = READ | do_sync;
1675 bio->bi_private = r1_bio;
1676 unplug = 1;
1677 generic_make_request(bio);
1678 }
1679 }
1680 cond_resched();
1681 }
1682 if (unplug)
1683 unplug_slaves(mddev);
1684 }
1685
1686
1687 static int init_resync(conf_t *conf)
1688 {
1689 int buffs;
1690
1691 buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE;
1692 BUG_ON(conf->r1buf_pool);
1693 conf->r1buf_pool = mempool_create(buffs, r1buf_pool_alloc, r1buf_pool_free,
1694 conf->poolinfo);
1695 if (!conf->r1buf_pool)
1696 return -ENOMEM;
1697 conf->next_resync = 0;
1698 return 0;
1699 }
1700
1701 /*
1702 * perform a "sync" on one "block"
1703 *
1704 * We need to make sure that no normal I/O request - particularly write
1705 * requests - conflict with active sync requests.
1706 *
1707 * This is achieved by tracking pending requests and a 'barrier' concept
1708 * that can be installed to exclude normal IO requests.
1709 */
1710
1711 static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster)
1712 {
1713 conf_t *conf = mddev->private;
1714 r1bio_t *r1_bio;
1715 struct bio *bio;
1716 sector_t max_sector, nr_sectors;
1717 int disk = -1;
1718 int i;
1719 int wonly = -1;
1720 int write_targets = 0, read_targets = 0;
1721 int sync_blocks;
1722 int still_degraded = 0;
1723
1724 if (!conf->r1buf_pool)
1725 {
1726 /*
1727 printk("sync start - bitmap %p\n", mddev->bitmap);
1728 */
1729 if (init_resync(conf))
1730 return 0;
1731 }
1732
1733 max_sector = mddev->dev_sectors;
1734 if (sector_nr >= max_sector) {
1735 /* If we aborted, we need to abort the
1736 * sync on the 'current' bitmap chunk (there will
1737 * only be one in raid1 resync.
1738 * We can find the current addess in mddev->curr_resync
1739 */
1740 if (mddev->curr_resync < max_sector) /* aborted */
1741 bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
1742 &sync_blocks, 1);
1743 else /* completed sync */
1744 conf->fullsync = 0;
1745
1746 bitmap_close_sync(mddev->bitmap);
1747 close_sync(conf);
1748 return 0;
1749 }
1750
1751 if (mddev->bitmap == NULL &&
1752 mddev->recovery_cp == MaxSector &&
1753 !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
1754 conf->fullsync == 0) {
1755 *skipped = 1;
1756 return max_sector - sector_nr;
1757 }
1758 /* before building a request, check if we can skip these blocks..
1759 * This call the bitmap_start_sync doesn't actually record anything
1760 */
1761 if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
1762 !conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
1763 /* We can skip this block, and probably several more */
1764 *skipped = 1;
1765 return sync_blocks;
1766 }
1767 /*
1768 * If there is non-resync activity waiting for a turn,
1769 * and resync is going fast enough,
1770 * then let it though before starting on this new sync request.
1771 */
1772 if (!go_faster && conf->nr_waiting)
1773 msleep_interruptible(1000);
1774
1775 bitmap_cond_end_sync(mddev->bitmap, sector_nr);
1776 raise_barrier(conf);
1777
1778 conf->next_resync = sector_nr;
1779
1780 r1_bio = mempool_alloc(conf->r1buf_pool, GFP_NOIO);
1781 rcu_read_lock();
1782 /*
1783 * If we get a correctably read error during resync or recovery,
1784 * we might want to read from a different device. So we
1785 * flag all drives that could conceivably be read from for READ,
1786 * and any others (which will be non-In_sync devices) for WRITE.
1787 * If a read fails, we try reading from something else for which READ
1788 * is OK.
1789 */
1790
1791 r1_bio->mddev = mddev;
1792 r1_bio->sector = sector_nr;
1793 r1_bio->state = 0;
1794 set_bit(R1BIO_IsSync, &r1_bio->state);
1795
1796 for (i=0; i < conf->raid_disks; i++) {
1797 mdk_rdev_t *rdev;
1798 bio = r1_bio->bios[i];
1799
1800 /* take from bio_init */
1801 bio->bi_next = NULL;
1802 bio->bi_flags |= 1 << BIO_UPTODATE;
1803 bio->bi_rw = READ;
1804 bio->bi_vcnt = 0;
1805 bio->bi_idx = 0;
1806 bio->bi_phys_segments = 0;
1807 bio->bi_size = 0;
1808 bio->bi_end_io = NULL;
1809 bio->bi_private = NULL;
1810
1811 rdev = rcu_dereference(conf->mirrors[i].rdev);
1812 if (rdev == NULL ||
1813 test_bit(Faulty, &rdev->flags)) {
1814 still_degraded = 1;
1815 continue;
1816 } else if (!test_bit(In_sync, &rdev->flags)) {
1817 bio->bi_rw = WRITE;
1818 bio->bi_end_io = end_sync_write;
1819 write_targets ++;
1820 } else {
1821 /* may need to read from here */
1822 bio->bi_rw = READ;
1823 bio->bi_end_io = end_sync_read;
1824 if (test_bit(WriteMostly, &rdev->flags)) {
1825 if (wonly < 0)
1826 wonly = i;
1827 } else {
1828 if (disk < 0)
1829 disk = i;
1830 }
1831 read_targets++;
1832 }
1833 atomic_inc(&rdev->nr_pending);
1834 bio->bi_sector = sector_nr + rdev->data_offset;
1835 bio->bi_bdev = rdev->bdev;
1836 bio->bi_private = r1_bio;
1837 }
1838 rcu_read_unlock();
1839 if (disk < 0)
1840 disk = wonly;
1841 r1_bio->read_disk = disk;
1842
1843 if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) && read_targets > 0)
1844 /* extra read targets are also write targets */
1845 write_targets += read_targets-1;
1846
1847 if (write_targets == 0 || read_targets == 0) {
1848 /* There is nowhere to write, so all non-sync
1849 * drives must be failed - so we are finished
1850 */
1851 sector_t rv = max_sector - sector_nr;
1852 *skipped = 1;
1853 put_buf(r1_bio);
1854 return rv;
1855 }
1856
1857 if (max_sector > mddev->resync_max)
1858 max_sector = mddev->resync_max; /* Don't do IO beyond here */
1859 nr_sectors = 0;
1860 sync_blocks = 0;
1861 do {
1862 struct page *page;
1863 int len = PAGE_SIZE;
1864 if (sector_nr + (len>>9) > max_sector)
1865 len = (max_sector - sector_nr) << 9;
1866 if (len == 0)
1867 break;
1868 if (sync_blocks == 0) {
1869 if (!bitmap_start_sync(mddev->bitmap, sector_nr,
1870 &sync_blocks, still_degraded) &&
1871 !conf->fullsync &&
1872 !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
1873 break;
1874 BUG_ON(sync_blocks < (PAGE_SIZE>>9));
1875 if (len > (sync_blocks<<9))
1876 len = sync_blocks<<9;
1877 }
1878
1879 for (i=0 ; i < conf->raid_disks; i++) {
1880 bio = r1_bio->bios[i];
1881 if (bio->bi_end_io) {
1882 page = bio->bi_io_vec[bio->bi_vcnt].bv_page;
1883 if (bio_add_page(bio, page, len, 0) == 0) {
1884 /* stop here */
1885 bio->bi_io_vec[bio->bi_vcnt].bv_page = page;
1886 while (i > 0) {
1887 i--;
1888 bio = r1_bio->bios[i];
1889 if (bio->bi_end_io==NULL)
1890 continue;
1891 /* remove last page from this bio */
1892 bio->bi_vcnt--;
1893 bio->bi_size -= len;
1894 bio->bi_flags &= ~(1<< BIO_SEG_VALID);
1895 }
1896 goto bio_full;
1897 }
1898 }
1899 }
1900 nr_sectors += len>>9;
1901 sector_nr += len>>9;
1902 sync_blocks -= (len>>9);
1903 } while (r1_bio->bios[disk]->bi_vcnt < RESYNC_PAGES);
1904 bio_full:
1905 r1_bio->sectors = nr_sectors;
1906
1907 /* For a user-requested sync, we read all readable devices and do a
1908 * compare
1909 */
1910 if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
1911 atomic_set(&r1_bio->remaining, read_targets);
1912 for (i=0; i<conf->raid_disks; i++) {
1913 bio = r1_bio->bios[i];
1914 if (bio->bi_end_io == end_sync_read) {
1915 md_sync_acct(bio->bi_bdev, nr_sectors);
1916 generic_make_request(bio);
1917 }
1918 }
1919 } else {
1920 atomic_set(&r1_bio->remaining, 1);
1921 bio = r1_bio->bios[r1_bio->read_disk];
1922 md_sync_acct(bio->bi_bdev, nr_sectors);
1923 generic_make_request(bio);
1924
1925 }
1926 return nr_sectors;
1927 }
1928
1929 static sector_t raid1_size(mddev_t *mddev, sector_t sectors, int raid_disks)
1930 {
1931 if (sectors)
1932 return sectors;
1933
1934 return mddev->dev_sectors;
1935 }
1936
1937 static int run(mddev_t *mddev)
1938 {
1939 conf_t *conf;
1940 int i, j, disk_idx;
1941 mirror_info_t *disk;
1942 mdk_rdev_t *rdev;
1943
1944 if (mddev->level != 1) {
1945 printk("raid1: %s: raid level not set to mirroring (%d)\n",
1946 mdname(mddev), mddev->level);
1947 goto out;
1948 }
1949 if (mddev->reshape_position != MaxSector) {
1950 printk("raid1: %s: reshape_position set but not supported\n",
1951 mdname(mddev));
1952 goto out;
1953 }
1954 /*
1955 * copy the already verified devices into our private RAID1
1956 * bookkeeping area. [whatever we allocate in run(),
1957 * should be freed in stop()]
1958 */
1959 conf = kzalloc(sizeof(conf_t), GFP_KERNEL);
1960 mddev->private = conf;
1961 if (!conf)
1962 goto out_no_mem;
1963
1964 conf->mirrors = kzalloc(sizeof(struct mirror_info)*mddev->raid_disks,
1965 GFP_KERNEL);
1966 if (!conf->mirrors)
1967 goto out_no_mem;
1968
1969 conf->tmppage = alloc_page(GFP_KERNEL);
1970 if (!conf->tmppage)
1971 goto out_no_mem;
1972
1973 conf->poolinfo = kmalloc(sizeof(*conf->poolinfo), GFP_KERNEL);
1974 if (!conf->poolinfo)
1975 goto out_no_mem;
1976 conf->poolinfo->mddev = mddev;
1977 conf->poolinfo->raid_disks = mddev->raid_disks;
1978 conf->r1bio_pool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc,
1979 r1bio_pool_free,
1980 conf->poolinfo);
1981 if (!conf->r1bio_pool)
1982 goto out_no_mem;
1983
1984 spin_lock_init(&conf->device_lock);
1985 mddev->queue->queue_lock = &conf->device_lock;
1986
1987 list_for_each_entry(rdev, &mddev->disks, same_set) {
1988 disk_idx = rdev->raid_disk;
1989 if (disk_idx >= mddev->raid_disks
1990 || disk_idx < 0)
1991 continue;
1992 disk = conf->mirrors + disk_idx;
1993
1994 disk->rdev = rdev;
1995 disk_stack_limits(mddev->gendisk, rdev->bdev,
1996 rdev->data_offset << 9);
1997 /* as we don't honour merge_bvec_fn, we must never risk
1998 * violating it, so limit ->max_sector to one PAGE, as
1999 * a one page request is never in violation.
2000 */
2001 if (rdev->bdev->bd_disk->queue->merge_bvec_fn &&
2002 queue_max_sectors(mddev->queue) > (PAGE_SIZE>>9))
2003 blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9);
2004
2005 disk->head_position = 0;
2006 }
2007 conf->raid_disks = mddev->raid_disks;
2008 conf->mddev = mddev;
2009 INIT_LIST_HEAD(&conf->retry_list);
2010
2011 spin_lock_init(&conf->resync_lock);
2012 init_waitqueue_head(&conf->wait_barrier);
2013
2014 bio_list_init(&conf->pending_bio_list);
2015 bio_list_init(&conf->flushing_bio_list);
2016
2017
2018 mddev->degraded = 0;
2019 for (i = 0; i < conf->raid_disks; i++) {
2020
2021 disk = conf->mirrors + i;
2022
2023 if (!disk->rdev ||
2024 !test_bit(In_sync, &disk->rdev->flags)) {
2025 disk->head_position = 0;
2026 mddev->degraded++;
2027 if (disk->rdev)
2028 conf->fullsync = 1;
2029 }
2030 }
2031 if (mddev->degraded == conf->raid_disks) {
2032 printk(KERN_ERR "raid1: no operational mirrors for %s\n",
2033 mdname(mddev));
2034 goto out_free_conf;
2035 }
2036 if (conf->raid_disks - mddev->degraded == 1)
2037 mddev->recovery_cp = MaxSector;
2038
2039 /*
2040 * find the first working one and use it as a starting point
2041 * to read balancing.
2042 */
2043 for (j = 0; j < conf->raid_disks &&
2044 (!conf->mirrors[j].rdev ||
2045 !test_bit(In_sync, &conf->mirrors[j].rdev->flags)) ; j++)
2046 /* nothing */;
2047 conf->last_used = j;
2048
2049
2050 mddev->thread = md_register_thread(raid1d, mddev, "%s_raid1");
2051 if (!mddev->thread) {
2052 printk(KERN_ERR
2053 "raid1: couldn't allocate thread for %s\n",
2054 mdname(mddev));
2055 goto out_free_conf;
2056 }
2057
2058 if (mddev->recovery_cp != MaxSector)
2059 printk(KERN_NOTICE "raid1: %s is not clean"
2060 " -- starting background reconstruction\n",
2061 mdname(mddev));
2062 printk(KERN_INFO
2063 "raid1: raid set %s active with %d out of %d mirrors\n",
2064 mdname(mddev), mddev->raid_disks - mddev->degraded,
2065 mddev->raid_disks);
2066 /*
2067 * Ok, everything is just fine now
2068 */
2069 md_set_array_sectors(mddev, raid1_size(mddev, 0, 0));
2070
2071 mddev->queue->unplug_fn = raid1_unplug;
2072 mddev->queue->backing_dev_info.congested_fn = raid1_congested;
2073 mddev->queue->backing_dev_info.congested_data = mddev;
2074 md_integrity_register(mddev);
2075 return 0;
2076
2077 out_no_mem:
2078 printk(KERN_ERR "raid1: couldn't allocate memory for %s\n",
2079 mdname(mddev));
2080
2081 out_free_conf:
2082 if (conf) {
2083 if (conf->r1bio_pool)
2084 mempool_destroy(conf->r1bio_pool);
2085 kfree(conf->mirrors);
2086 safe_put_page(conf->tmppage);
2087 kfree(conf->poolinfo);
2088 kfree(conf);
2089 mddev->private = NULL;
2090 }
2091 out:
2092 return -EIO;
2093 }
2094
2095 static int stop(mddev_t *mddev)
2096 {
2097 conf_t *conf = mddev->private;
2098 struct bitmap *bitmap = mddev->bitmap;
2099 int behind_wait = 0;
2100
2101 /* wait for behind writes to complete */
2102 while (bitmap && atomic_read(&bitmap->behind_writes) > 0) {
2103 behind_wait++;
2104 printk(KERN_INFO "raid1: behind writes in progress on device %s, waiting to stop (%d)\n", mdname(mddev), behind_wait);
2105 set_current_state(TASK_UNINTERRUPTIBLE);
2106 schedule_timeout(HZ); /* wait a second */
2107 /* need to kick something here to make sure I/O goes? */
2108 }
2109
2110 raise_barrier(conf);
2111 lower_barrier(conf);
2112
2113 md_unregister_thread(mddev->thread);
2114 mddev->thread = NULL;
2115 blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
2116 if (conf->r1bio_pool)
2117 mempool_destroy(conf->r1bio_pool);
2118 kfree(conf->mirrors);
2119 kfree(conf->poolinfo);
2120 kfree(conf);
2121 mddev->private = NULL;
2122 return 0;
2123 }
2124
2125 static int raid1_resize(mddev_t *mddev, sector_t sectors)
2126 {
2127 /* no resync is happening, and there is enough space
2128 * on all devices, so we can resize.
2129 * We need to make sure resync covers any new space.
2130 * If the array is shrinking we should possibly wait until
2131 * any io in the removed space completes, but it hardly seems
2132 * worth it.
2133 */
2134 md_set_array_sectors(mddev, raid1_size(mddev, sectors, 0));
2135 if (mddev->array_sectors > raid1_size(mddev, sectors, 0))
2136 return -EINVAL;
2137 set_capacity(mddev->gendisk, mddev->array_sectors);
2138 mddev->changed = 1;
2139 revalidate_disk(mddev->gendisk);
2140 if (sectors > mddev->dev_sectors &&
2141 mddev->recovery_cp == MaxSector) {
2142 mddev->recovery_cp = mddev->dev_sectors;
2143 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
2144 }
2145 mddev->dev_sectors = sectors;
2146 mddev->resync_max_sectors = sectors;
2147 return 0;
2148 }
2149
2150 static int raid1_reshape(mddev_t *mddev)
2151 {
2152 /* We need to:
2153 * 1/ resize the r1bio_pool
2154 * 2/ resize conf->mirrors
2155 *
2156 * We allocate a new r1bio_pool if we can.
2157 * Then raise a device barrier and wait until all IO stops.
2158 * Then resize conf->mirrors and swap in the new r1bio pool.
2159 *
2160 * At the same time, we "pack" the devices so that all the missing
2161 * devices have the higher raid_disk numbers.
2162 */
2163 mempool_t *newpool, *oldpool;
2164 struct pool_info *newpoolinfo;
2165 mirror_info_t *newmirrors;
2166 conf_t *conf = mddev->private;
2167 int cnt, raid_disks;
2168 unsigned long flags;
2169 int d, d2, err;
2170
2171 /* Cannot change chunk_size, layout, or level */
2172 if (mddev->chunk_sectors != mddev->new_chunk_sectors ||
2173 mddev->layout != mddev->new_layout ||
2174 mddev->level != mddev->new_level) {
2175 mddev->new_chunk_sectors = mddev->chunk_sectors;
2176 mddev->new_layout = mddev->layout;
2177 mddev->new_level = mddev->level;
2178 return -EINVAL;
2179 }
2180
2181 err = md_allow_write(mddev);
2182 if (err)
2183 return err;
2184
2185 raid_disks = mddev->raid_disks + mddev->delta_disks;
2186
2187 if (raid_disks < conf->raid_disks) {
2188 cnt=0;
2189 for (d= 0; d < conf->raid_disks; d++)
2190 if (conf->mirrors[d].rdev)
2191 cnt++;
2192 if (cnt > raid_disks)
2193 return -EBUSY;
2194 }
2195
2196 newpoolinfo = kmalloc(sizeof(*newpoolinfo), GFP_KERNEL);
2197 if (!newpoolinfo)
2198 return -ENOMEM;
2199 newpoolinfo->mddev = mddev;
2200 newpoolinfo->raid_disks = raid_disks;
2201
2202 newpool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc,
2203 r1bio_pool_free, newpoolinfo);
2204 if (!newpool) {
2205 kfree(newpoolinfo);
2206 return -ENOMEM;
2207 }
2208 newmirrors = kzalloc(sizeof(struct mirror_info) * raid_disks, GFP_KERNEL);
2209 if (!newmirrors) {
2210 kfree(newpoolinfo);
2211 mempool_destroy(newpool);
2212 return -ENOMEM;
2213 }
2214
2215 raise_barrier(conf);
2216
2217 /* ok, everything is stopped */
2218 oldpool = conf->r1bio_pool;
2219 conf->r1bio_pool = newpool;
2220
2221 for (d = d2 = 0; d < conf->raid_disks; d++) {
2222 mdk_rdev_t *rdev = conf->mirrors[d].rdev;
2223 if (rdev && rdev->raid_disk != d2) {
2224 char nm[20];
2225 sprintf(nm, "rd%d", rdev->raid_disk);
2226 sysfs_remove_link(&mddev->kobj, nm);
2227 rdev->raid_disk = d2;
2228 sprintf(nm, "rd%d", rdev->raid_disk);
2229 sysfs_remove_link(&mddev->kobj, nm);
2230 if (sysfs_create_link(&mddev->kobj,
2231 &rdev->kobj, nm))
2232 printk(KERN_WARNING
2233 "md/raid1: cannot register "
2234 "%s for %s\n",
2235 nm, mdname(mddev));
2236 }
2237 if (rdev)
2238 newmirrors[d2++].rdev = rdev;
2239 }
2240 kfree(conf->mirrors);
2241 conf->mirrors = newmirrors;
2242 kfree(conf->poolinfo);
2243 conf->poolinfo = newpoolinfo;
2244
2245 spin_lock_irqsave(&conf->device_lock, flags);
2246 mddev->degraded += (raid_disks - conf->raid_disks);
2247 spin_unlock_irqrestore(&conf->device_lock, flags);
2248 conf->raid_disks = mddev->raid_disks = raid_disks;
2249 mddev->delta_disks = 0;
2250
2251 conf->last_used = 0; /* just make sure it is in-range */
2252 lower_barrier(conf);
2253
2254 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
2255 md_wakeup_thread(mddev->thread);
2256
2257 mempool_destroy(oldpool);
2258 return 0;
2259 }
2260
2261 static void raid1_quiesce(mddev_t *mddev, int state)
2262 {
2263 conf_t *conf = mddev->private;
2264
2265 switch(state) {
2266 case 1:
2267 raise_barrier(conf);
2268 break;
2269 case 0:
2270 lower_barrier(conf);
2271 break;
2272 }
2273 }
2274
2275
2276 static struct mdk_personality raid1_personality =
2277 {
2278 .name = "raid1",
2279 .level = 1,
2280 .owner = THIS_MODULE,
2281 .make_request = make_request,
2282 .run = run,
2283 .stop = stop,
2284 .status = status,
2285 .error_handler = error,
2286 .hot_add_disk = raid1_add_disk,
2287 .hot_remove_disk= raid1_remove_disk,
2288 .spare_active = raid1_spare_active,
2289 .sync_request = sync_request,
2290 .resize = raid1_resize,
2291 .size = raid1_size,
2292 .check_reshape = raid1_reshape,
2293 .quiesce = raid1_quiesce,
2294 };
2295
2296 static int __init raid_init(void)
2297 {
2298 return register_md_personality(&raid1_personality);
2299 }
2300
2301 static void raid_exit(void)
2302 {
2303 unregister_md_personality(&raid1_personality);
2304 }
2305
2306 module_init(raid_init);
2307 module_exit(raid_exit);
2308 MODULE_LICENSE("GPL");
2309 MODULE_ALIAS("md-personality-3"); /* RAID1 */
2310 MODULE_ALIAS("md-raid1");
2311 MODULE_ALIAS("md-level-1");
2312
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