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md: implment REQ_FLUSH/FUA support
[deliverable/linux.git] / drivers / md / raid1.c
1 /*
2 * raid1.c : Multiple Devices driver for Linux
3 *
4 * Copyright (C) 1999, 2000, 2001 Ingo Molnar, Red Hat
5 *
6 * Copyright (C) 1996, 1997, 1998 Ingo Molnar, Miguel de Icaza, Gadi Oxman
7 *
8 * RAID-1 management functions.
9 *
10 * Better read-balancing code written by Mika Kuoppala <miku@iki.fi>, 2000
11 *
12 * Fixes to reconstruction by Jakob Østergaard" <jakob@ostenfeld.dk>
13 * Various fixes by Neil Brown <neilb@cse.unsw.edu.au>
14 *
15 * Changes by Peter T. Breuer <ptb@it.uc3m.es> 31/1/2003 to support
16 * bitmapped intelligence in resync:
17 *
18 * - bitmap marked during normal i/o
19 * - bitmap used to skip nondirty blocks during sync
20 *
21 * Additions to bitmap code, (C) 2003-2004 Paul Clements, SteelEye Technology:
22 * - persistent bitmap code
23 *
24 * This program is free software; you can redistribute it and/or modify
25 * it under the terms of the GNU General Public License as published by
26 * the Free Software Foundation; either version 2, or (at your option)
27 * any later version.
28 *
29 * You should have received a copy of the GNU General Public License
30 * (for example /usr/src/linux/COPYING); if not, write to the Free
31 * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
32 */
33
34 #include <linux/slab.h>
35 #include <linux/delay.h>
36 #include <linux/blkdev.h>
37 #include <linux/seq_file.h>
38 #include "md.h"
39 #include "raid1.h"
40 #include "bitmap.h"
41
42 #define DEBUG 0
43 #if DEBUG
44 #define PRINTK(x...) printk(x)
45 #else
46 #define PRINTK(x...)
47 #endif
48
49 /*
50 * Number of guaranteed r1bios in case of extreme VM load:
51 */
52 #define NR_RAID1_BIOS 256
53
54
55 static void unplug_slaves(mddev_t *mddev);
56
57 static void allow_barrier(conf_t *conf);
58 static void lower_barrier(conf_t *conf);
59
60 static void * r1bio_pool_alloc(gfp_t gfp_flags, void *data)
61 {
62 struct pool_info *pi = data;
63 r1bio_t *r1_bio;
64 int size = offsetof(r1bio_t, bios[pi->raid_disks]);
65
66 /* allocate a r1bio with room for raid_disks entries in the bios array */
67 r1_bio = kzalloc(size, gfp_flags);
68 if (!r1_bio && pi->mddev)
69 unplug_slaves(pi->mddev);
70
71 return r1_bio;
72 }
73
74 static void r1bio_pool_free(void *r1_bio, void *data)
75 {
76 kfree(r1_bio);
77 }
78
79 #define RESYNC_BLOCK_SIZE (64*1024)
80 //#define RESYNC_BLOCK_SIZE PAGE_SIZE
81 #define RESYNC_SECTORS (RESYNC_BLOCK_SIZE >> 9)
82 #define RESYNC_PAGES ((RESYNC_BLOCK_SIZE + PAGE_SIZE-1) / PAGE_SIZE)
83 #define RESYNC_WINDOW (2048*1024)
84
85 static void * r1buf_pool_alloc(gfp_t gfp_flags, void *data)
86 {
87 struct pool_info *pi = data;
88 struct page *page;
89 r1bio_t *r1_bio;
90 struct bio *bio;
91 int i, j;
92
93 r1_bio = r1bio_pool_alloc(gfp_flags, pi);
94 if (!r1_bio) {
95 unplug_slaves(pi->mddev);
96 return NULL;
97 }
98
99 /*
100 * Allocate bios : 1 for reading, n-1 for writing
101 */
102 for (j = pi->raid_disks ; j-- ; ) {
103 bio = bio_alloc(gfp_flags, RESYNC_PAGES);
104 if (!bio)
105 goto out_free_bio;
106 r1_bio->bios[j] = bio;
107 }
108 /*
109 * Allocate RESYNC_PAGES data pages and attach them to
110 * the first bio.
111 * If this is a user-requested check/repair, allocate
112 * RESYNC_PAGES for each bio.
113 */
114 if (test_bit(MD_RECOVERY_REQUESTED, &pi->mddev->recovery))
115 j = pi->raid_disks;
116 else
117 j = 1;
118 while(j--) {
119 bio = r1_bio->bios[j];
120 for (i = 0; i < RESYNC_PAGES; i++) {
121 page = alloc_page(gfp_flags);
122 if (unlikely(!page))
123 goto out_free_pages;
124
125 bio->bi_io_vec[i].bv_page = page;
126 bio->bi_vcnt = i+1;
127 }
128 }
129 /* If not user-requests, copy the page pointers to all bios */
130 if (!test_bit(MD_RECOVERY_REQUESTED, &pi->mddev->recovery)) {
131 for (i=0; i<RESYNC_PAGES ; i++)
132 for (j=1; j<pi->raid_disks; j++)
133 r1_bio->bios[j]->bi_io_vec[i].bv_page =
134 r1_bio->bios[0]->bi_io_vec[i].bv_page;
135 }
136
137 r1_bio->master_bio = NULL;
138
139 return r1_bio;
140
141 out_free_pages:
142 for (j=0 ; j < pi->raid_disks; j++)
143 for (i=0; i < r1_bio->bios[j]->bi_vcnt ; i++)
144 put_page(r1_bio->bios[j]->bi_io_vec[i].bv_page);
145 j = -1;
146 out_free_bio:
147 while ( ++j < pi->raid_disks )
148 bio_put(r1_bio->bios[j]);
149 r1bio_pool_free(r1_bio, data);
150 return NULL;
151 }
152
153 static void r1buf_pool_free(void *__r1_bio, void *data)
154 {
155 struct pool_info *pi = data;
156 int i,j;
157 r1bio_t *r1bio = __r1_bio;
158
159 for (i = 0; i < RESYNC_PAGES; i++)
160 for (j = pi->raid_disks; j-- ;) {
161 if (j == 0 ||
162 r1bio->bios[j]->bi_io_vec[i].bv_page !=
163 r1bio->bios[0]->bi_io_vec[i].bv_page)
164 safe_put_page(r1bio->bios[j]->bi_io_vec[i].bv_page);
165 }
166 for (i=0 ; i < pi->raid_disks; i++)
167 bio_put(r1bio->bios[i]);
168
169 r1bio_pool_free(r1bio, data);
170 }
171
172 static void put_all_bios(conf_t *conf, r1bio_t *r1_bio)
173 {
174 int i;
175
176 for (i = 0; i < conf->raid_disks; i++) {
177 struct bio **bio = r1_bio->bios + i;
178 if (*bio && *bio != IO_BLOCKED)
179 bio_put(*bio);
180 *bio = NULL;
181 }
182 }
183
184 static void free_r1bio(r1bio_t *r1_bio)
185 {
186 conf_t *conf = r1_bio->mddev->private;
187
188 /*
189 * Wake up any possible resync thread that waits for the device
190 * to go idle.
191 */
192 allow_barrier(conf);
193
194 put_all_bios(conf, r1_bio);
195 mempool_free(r1_bio, conf->r1bio_pool);
196 }
197
198 static void put_buf(r1bio_t *r1_bio)
199 {
200 conf_t *conf = r1_bio->mddev->private;
201 int i;
202
203 for (i=0; i<conf->raid_disks; i++) {
204 struct bio *bio = r1_bio->bios[i];
205 if (bio->bi_end_io)
206 rdev_dec_pending(conf->mirrors[i].rdev, r1_bio->mddev);
207 }
208
209 mempool_free(r1_bio, conf->r1buf_pool);
210
211 lower_barrier(conf);
212 }
213
214 static void reschedule_retry(r1bio_t *r1_bio)
215 {
216 unsigned long flags;
217 mddev_t *mddev = r1_bio->mddev;
218 conf_t *conf = mddev->private;
219
220 spin_lock_irqsave(&conf->device_lock, flags);
221 list_add(&r1_bio->retry_list, &conf->retry_list);
222 conf->nr_queued ++;
223 spin_unlock_irqrestore(&conf->device_lock, flags);
224
225 wake_up(&conf->wait_barrier);
226 md_wakeup_thread(mddev->thread);
227 }
228
229 /*
230 * raid_end_bio_io() is called when we have finished servicing a mirrored
231 * operation and are ready to return a success/failure code to the buffer
232 * cache layer.
233 */
234 static void raid_end_bio_io(r1bio_t *r1_bio)
235 {
236 struct bio *bio = r1_bio->master_bio;
237
238 /* if nobody has done the final endio yet, do it now */
239 if (!test_and_set_bit(R1BIO_Returned, &r1_bio->state)) {
240 PRINTK(KERN_DEBUG "raid1: sync end %s on sectors %llu-%llu\n",
241 (bio_data_dir(bio) == WRITE) ? "write" : "read",
242 (unsigned long long) bio->bi_sector,
243 (unsigned long long) bio->bi_sector +
244 (bio->bi_size >> 9) - 1);
245
246 bio_endio(bio,
247 test_bit(R1BIO_Uptodate, &r1_bio->state) ? 0 : -EIO);
248 }
249 free_r1bio(r1_bio);
250 }
251
252 /*
253 * Update disk head position estimator based on IRQ completion info.
254 */
255 static inline void update_head_pos(int disk, r1bio_t *r1_bio)
256 {
257 conf_t *conf = r1_bio->mddev->private;
258
259 conf->mirrors[disk].head_position =
260 r1_bio->sector + (r1_bio->sectors);
261 }
262
263 static void raid1_end_read_request(struct bio *bio, int error)
264 {
265 int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
266 r1bio_t *r1_bio = bio->bi_private;
267 int mirror;
268 conf_t *conf = r1_bio->mddev->private;
269
270 mirror = r1_bio->read_disk;
271 /*
272 * this branch is our 'one mirror IO has finished' event handler:
273 */
274 update_head_pos(mirror, r1_bio);
275
276 if (uptodate)
277 set_bit(R1BIO_Uptodate, &r1_bio->state);
278 else {
279 /* If all other devices have failed, we want to return
280 * the error upwards rather than fail the last device.
281 * Here we redefine "uptodate" to mean "Don't want to retry"
282 */
283 unsigned long flags;
284 spin_lock_irqsave(&conf->device_lock, flags);
285 if (r1_bio->mddev->degraded == conf->raid_disks ||
286 (r1_bio->mddev->degraded == conf->raid_disks-1 &&
287 !test_bit(Faulty, &conf->mirrors[mirror].rdev->flags)))
288 uptodate = 1;
289 spin_unlock_irqrestore(&conf->device_lock, flags);
290 }
291
292 if (uptodate)
293 raid_end_bio_io(r1_bio);
294 else {
295 /*
296 * oops, read error:
297 */
298 char b[BDEVNAME_SIZE];
299 if (printk_ratelimit())
300 printk(KERN_ERR "md/raid1:%s: %s: rescheduling sector %llu\n",
301 mdname(conf->mddev),
302 bdevname(conf->mirrors[mirror].rdev->bdev,b), (unsigned long long)r1_bio->sector);
303 reschedule_retry(r1_bio);
304 }
305
306 rdev_dec_pending(conf->mirrors[mirror].rdev, conf->mddev);
307 }
308
309 static void raid1_end_write_request(struct bio *bio, int error)
310 {
311 int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
312 r1bio_t *r1_bio = bio->bi_private;
313 int mirror, behind = test_bit(R1BIO_BehindIO, &r1_bio->state);
314 conf_t *conf = r1_bio->mddev->private;
315 struct bio *to_put = NULL;
316
317
318 for (mirror = 0; mirror < conf->raid_disks; mirror++)
319 if (r1_bio->bios[mirror] == bio)
320 break;
321
322 /*
323 * 'one mirror IO has finished' event handler:
324 */
325 r1_bio->bios[mirror] = NULL;
326 to_put = bio;
327 if (!uptodate) {
328 md_error(r1_bio->mddev, conf->mirrors[mirror].rdev);
329 /* an I/O failed, we can't clear the bitmap */
330 set_bit(R1BIO_Degraded, &r1_bio->state);
331 } else
332 /*
333 * Set R1BIO_Uptodate in our master bio, so that we
334 * will return a good error code for to the higher
335 * levels even if IO on some other mirrored buffer
336 * fails.
337 *
338 * The 'master' represents the composite IO operation
339 * to user-side. So if something waits for IO, then it
340 * will wait for the 'master' bio.
341 */
342 set_bit(R1BIO_Uptodate, &r1_bio->state);
343
344 update_head_pos(mirror, r1_bio);
345
346 if (behind) {
347 if (test_bit(WriteMostly, &conf->mirrors[mirror].rdev->flags))
348 atomic_dec(&r1_bio->behind_remaining);
349
350 /*
351 * In behind mode, we ACK the master bio once the I/O
352 * has safely reached all non-writemostly
353 * disks. Setting the Returned bit ensures that this
354 * gets done only once -- we don't ever want to return
355 * -EIO here, instead we'll wait
356 */
357 if (atomic_read(&r1_bio->behind_remaining) >= (atomic_read(&r1_bio->remaining)-1) &&
358 test_bit(R1BIO_Uptodate, &r1_bio->state)) {
359 /* Maybe we can return now */
360 if (!test_and_set_bit(R1BIO_Returned, &r1_bio->state)) {
361 struct bio *mbio = r1_bio->master_bio;
362 PRINTK(KERN_DEBUG "raid1: behind end write sectors %llu-%llu\n",
363 (unsigned long long) mbio->bi_sector,
364 (unsigned long long) mbio->bi_sector +
365 (mbio->bi_size >> 9) - 1);
366 bio_endio(mbio, 0);
367 }
368 }
369 }
370 rdev_dec_pending(conf->mirrors[mirror].rdev, conf->mddev);
371
372 /*
373 * Let's see if all mirrored write operations have finished
374 * already.
375 */
376 if (atomic_dec_and_test(&r1_bio->remaining)) {
377 if (test_bit(R1BIO_BehindIO, &r1_bio->state)) {
378 /* free extra copy of the data pages */
379 int i = bio->bi_vcnt;
380 while (i--)
381 safe_put_page(bio->bi_io_vec[i].bv_page);
382 }
383 /* clear the bitmap if all writes complete successfully */
384 bitmap_endwrite(r1_bio->mddev->bitmap, r1_bio->sector,
385 r1_bio->sectors,
386 !test_bit(R1BIO_Degraded, &r1_bio->state),
387 behind);
388 md_write_end(r1_bio->mddev);
389 raid_end_bio_io(r1_bio);
390 }
391
392 if (to_put)
393 bio_put(to_put);
394 }
395
396
397 /*
398 * This routine returns the disk from which the requested read should
399 * be done. There is a per-array 'next expected sequential IO' sector
400 * number - if this matches on the next IO then we use the last disk.
401 * There is also a per-disk 'last know head position' sector that is
402 * maintained from IRQ contexts, both the normal and the resync IO
403 * completion handlers update this position correctly. If there is no
404 * perfect sequential match then we pick the disk whose head is closest.
405 *
406 * If there are 2 mirrors in the same 2 devices, performance degrades
407 * because position is mirror, not device based.
408 *
409 * The rdev for the device selected will have nr_pending incremented.
410 */
411 static int read_balance(conf_t *conf, r1bio_t *r1_bio)
412 {
413 const sector_t this_sector = r1_bio->sector;
414 int new_disk = conf->last_used, disk = new_disk;
415 int wonly_disk = -1;
416 const int sectors = r1_bio->sectors;
417 sector_t new_distance, current_distance;
418 mdk_rdev_t *rdev;
419
420 rcu_read_lock();
421 /*
422 * Check if we can balance. We can balance on the whole
423 * device if no resync is going on, or below the resync window.
424 * We take the first readable disk when above the resync window.
425 */
426 retry:
427 if (conf->mddev->recovery_cp < MaxSector &&
428 (this_sector + sectors >= conf->next_resync)) {
429 /* Choose the first operational device, for consistancy */
430 new_disk = 0;
431
432 for (rdev = rcu_dereference(conf->mirrors[new_disk].rdev);
433 r1_bio->bios[new_disk] == IO_BLOCKED ||
434 !rdev || !test_bit(In_sync, &rdev->flags)
435 || test_bit(WriteMostly, &rdev->flags);
436 rdev = rcu_dereference(conf->mirrors[++new_disk].rdev)) {
437
438 if (rdev && test_bit(In_sync, &rdev->flags) &&
439 r1_bio->bios[new_disk] != IO_BLOCKED)
440 wonly_disk = new_disk;
441
442 if (new_disk == conf->raid_disks - 1) {
443 new_disk = wonly_disk;
444 break;
445 }
446 }
447 goto rb_out;
448 }
449
450
451 /* make sure the disk is operational */
452 for (rdev = rcu_dereference(conf->mirrors[new_disk].rdev);
453 r1_bio->bios[new_disk] == IO_BLOCKED ||
454 !rdev || !test_bit(In_sync, &rdev->flags) ||
455 test_bit(WriteMostly, &rdev->flags);
456 rdev = rcu_dereference(conf->mirrors[new_disk].rdev)) {
457
458 if (rdev && test_bit(In_sync, &rdev->flags) &&
459 r1_bio->bios[new_disk] != IO_BLOCKED)
460 wonly_disk = new_disk;
461
462 if (new_disk <= 0)
463 new_disk = conf->raid_disks;
464 new_disk--;
465 if (new_disk == disk) {
466 new_disk = wonly_disk;
467 break;
468 }
469 }
470
471 if (new_disk < 0)
472 goto rb_out;
473
474 disk = new_disk;
475 /* now disk == new_disk == starting point for search */
476
477 /*
478 * Don't change to another disk for sequential reads:
479 */
480 if (conf->next_seq_sect == this_sector)
481 goto rb_out;
482 if (this_sector == conf->mirrors[new_disk].head_position)
483 goto rb_out;
484
485 current_distance = abs(this_sector - conf->mirrors[disk].head_position);
486
487 /* Find the disk whose head is closest */
488
489 do {
490 if (disk <= 0)
491 disk = conf->raid_disks;
492 disk--;
493
494 rdev = rcu_dereference(conf->mirrors[disk].rdev);
495
496 if (!rdev || r1_bio->bios[disk] == IO_BLOCKED ||
497 !test_bit(In_sync, &rdev->flags) ||
498 test_bit(WriteMostly, &rdev->flags))
499 continue;
500
501 if (!atomic_read(&rdev->nr_pending)) {
502 new_disk = disk;
503 break;
504 }
505 new_distance = abs(this_sector - conf->mirrors[disk].head_position);
506 if (new_distance < current_distance) {
507 current_distance = new_distance;
508 new_disk = disk;
509 }
510 } while (disk != conf->last_used);
511
512 rb_out:
513
514
515 if (new_disk >= 0) {
516 rdev = rcu_dereference(conf->mirrors[new_disk].rdev);
517 if (!rdev)
518 goto retry;
519 atomic_inc(&rdev->nr_pending);
520 if (!test_bit(In_sync, &rdev->flags)) {
521 /* cannot risk returning a device that failed
522 * before we inc'ed nr_pending
523 */
524 rdev_dec_pending(rdev, conf->mddev);
525 goto retry;
526 }
527 conf->next_seq_sect = this_sector + sectors;
528 conf->last_used = new_disk;
529 }
530 rcu_read_unlock();
531
532 return new_disk;
533 }
534
535 static void unplug_slaves(mddev_t *mddev)
536 {
537 conf_t *conf = mddev->private;
538 int i;
539
540 rcu_read_lock();
541 for (i=0; i<mddev->raid_disks; i++) {
542 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
543 if (rdev && !test_bit(Faulty, &rdev->flags) && atomic_read(&rdev->nr_pending)) {
544 struct request_queue *r_queue = bdev_get_queue(rdev->bdev);
545
546 atomic_inc(&rdev->nr_pending);
547 rcu_read_unlock();
548
549 blk_unplug(r_queue);
550
551 rdev_dec_pending(rdev, mddev);
552 rcu_read_lock();
553 }
554 }
555 rcu_read_unlock();
556 }
557
558 static void raid1_unplug(struct request_queue *q)
559 {
560 mddev_t *mddev = q->queuedata;
561
562 unplug_slaves(mddev);
563 md_wakeup_thread(mddev->thread);
564 }
565
566 static int raid1_congested(void *data, int bits)
567 {
568 mddev_t *mddev = data;
569 conf_t *conf = mddev->private;
570 int i, ret = 0;
571
572 if (mddev_congested(mddev, bits))
573 return 1;
574
575 rcu_read_lock();
576 for (i = 0; i < mddev->raid_disks; i++) {
577 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
578 if (rdev && !test_bit(Faulty, &rdev->flags)) {
579 struct request_queue *q = bdev_get_queue(rdev->bdev);
580
581 /* Note the '|| 1' - when read_balance prefers
582 * non-congested targets, it can be removed
583 */
584 if ((bits & (1<<BDI_async_congested)) || 1)
585 ret |= bdi_congested(&q->backing_dev_info, bits);
586 else
587 ret &= bdi_congested(&q->backing_dev_info, bits);
588 }
589 }
590 rcu_read_unlock();
591 return ret;
592 }
593
594
595 static int flush_pending_writes(conf_t *conf)
596 {
597 /* Any writes that have been queued but are awaiting
598 * bitmap updates get flushed here.
599 * We return 1 if any requests were actually submitted.
600 */
601 int rv = 0;
602
603 spin_lock_irq(&conf->device_lock);
604
605 if (conf->pending_bio_list.head) {
606 struct bio *bio;
607 bio = bio_list_get(&conf->pending_bio_list);
608 blk_remove_plug(conf->mddev->queue);
609 spin_unlock_irq(&conf->device_lock);
610 /* flush any pending bitmap writes to
611 * disk before proceeding w/ I/O */
612 bitmap_unplug(conf->mddev->bitmap);
613
614 while (bio) { /* submit pending writes */
615 struct bio *next = bio->bi_next;
616 bio->bi_next = NULL;
617 generic_make_request(bio);
618 bio = next;
619 }
620 rv = 1;
621 } else
622 spin_unlock_irq(&conf->device_lock);
623 return rv;
624 }
625
626 /* Barriers....
627 * Sometimes we need to suspend IO while we do something else,
628 * either some resync/recovery, or reconfigure the array.
629 * To do this we raise a 'barrier'.
630 * The 'barrier' is a counter that can be raised multiple times
631 * to count how many activities are happening which preclude
632 * normal IO.
633 * We can only raise the barrier if there is no pending IO.
634 * i.e. if nr_pending == 0.
635 * We choose only to raise the barrier if no-one is waiting for the
636 * barrier to go down. This means that as soon as an IO request
637 * is ready, no other operations which require a barrier will start
638 * until the IO request has had a chance.
639 *
640 * So: regular IO calls 'wait_barrier'. When that returns there
641 * is no backgroup IO happening, It must arrange to call
642 * allow_barrier when it has finished its IO.
643 * backgroup IO calls must call raise_barrier. Once that returns
644 * there is no normal IO happeing. It must arrange to call
645 * lower_barrier when the particular background IO completes.
646 */
647 #define RESYNC_DEPTH 32
648
649 static void raise_barrier(conf_t *conf)
650 {
651 spin_lock_irq(&conf->resync_lock);
652
653 /* Wait until no block IO is waiting */
654 wait_event_lock_irq(conf->wait_barrier, !conf->nr_waiting,
655 conf->resync_lock,
656 raid1_unplug(conf->mddev->queue));
657
658 /* block any new IO from starting */
659 conf->barrier++;
660
661 /* No wait for all pending IO to complete */
662 wait_event_lock_irq(conf->wait_barrier,
663 !conf->nr_pending && conf->barrier < RESYNC_DEPTH,
664 conf->resync_lock,
665 raid1_unplug(conf->mddev->queue));
666
667 spin_unlock_irq(&conf->resync_lock);
668 }
669
670 static void lower_barrier(conf_t *conf)
671 {
672 unsigned long flags;
673 BUG_ON(conf->barrier <= 0);
674 spin_lock_irqsave(&conf->resync_lock, flags);
675 conf->barrier--;
676 spin_unlock_irqrestore(&conf->resync_lock, flags);
677 wake_up(&conf->wait_barrier);
678 }
679
680 static void wait_barrier(conf_t *conf)
681 {
682 spin_lock_irq(&conf->resync_lock);
683 if (conf->barrier) {
684 conf->nr_waiting++;
685 wait_event_lock_irq(conf->wait_barrier, !conf->barrier,
686 conf->resync_lock,
687 raid1_unplug(conf->mddev->queue));
688 conf->nr_waiting--;
689 }
690 conf->nr_pending++;
691 spin_unlock_irq(&conf->resync_lock);
692 }
693
694 static void allow_barrier(conf_t *conf)
695 {
696 unsigned long flags;
697 spin_lock_irqsave(&conf->resync_lock, flags);
698 conf->nr_pending--;
699 spin_unlock_irqrestore(&conf->resync_lock, flags);
700 wake_up(&conf->wait_barrier);
701 }
702
703 static void freeze_array(conf_t *conf)
704 {
705 /* stop syncio and normal IO and wait for everything to
706 * go quite.
707 * We increment barrier and nr_waiting, and then
708 * wait until nr_pending match nr_queued+1
709 * This is called in the context of one normal IO request
710 * that has failed. Thus any sync request that might be pending
711 * will be blocked by nr_pending, and we need to wait for
712 * pending IO requests to complete or be queued for re-try.
713 * Thus the number queued (nr_queued) plus this request (1)
714 * must match the number of pending IOs (nr_pending) before
715 * we continue.
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->nr_pending == conf->nr_queued+1,
722 conf->resync_lock,
723 ({ flush_pending_writes(conf);
724 raid1_unplug(conf->mddev->queue); }));
725 spin_unlock_irq(&conf->resync_lock);
726 }
727 static void unfreeze_array(conf_t *conf)
728 {
729 /* reverse the effect of the freeze */
730 spin_lock_irq(&conf->resync_lock);
731 conf->barrier--;
732 conf->nr_waiting--;
733 wake_up(&conf->wait_barrier);
734 spin_unlock_irq(&conf->resync_lock);
735 }
736
737
738 /* duplicate the data pages for behind I/O */
739 static struct page **alloc_behind_pages(struct bio *bio)
740 {
741 int i;
742 struct bio_vec *bvec;
743 struct page **pages = kzalloc(bio->bi_vcnt * sizeof(struct page *),
744 GFP_NOIO);
745 if (unlikely(!pages))
746 goto do_sync_io;
747
748 bio_for_each_segment(bvec, bio, i) {
749 pages[i] = alloc_page(GFP_NOIO);
750 if (unlikely(!pages[i]))
751 goto do_sync_io;
752 memcpy(kmap(pages[i]) + bvec->bv_offset,
753 kmap(bvec->bv_page) + bvec->bv_offset, bvec->bv_len);
754 kunmap(pages[i]);
755 kunmap(bvec->bv_page);
756 }
757
758 return pages;
759
760 do_sync_io:
761 if (pages)
762 for (i = 0; i < bio->bi_vcnt && pages[i]; i++)
763 put_page(pages[i]);
764 kfree(pages);
765 PRINTK("%dB behind alloc failed, doing sync I/O\n", bio->bi_size);
766 return NULL;
767 }
768
769 static int make_request(mddev_t *mddev, struct bio * bio)
770 {
771 conf_t *conf = mddev->private;
772 mirror_info_t *mirror;
773 r1bio_t *r1_bio;
774 struct bio *read_bio;
775 int i, targets = 0, disks;
776 struct bitmap *bitmap;
777 unsigned long flags;
778 struct bio_list bl;
779 struct page **behind_pages = NULL;
780 const int rw = bio_data_dir(bio);
781 const unsigned long do_sync = (bio->bi_rw & REQ_SYNC);
782 const unsigned long do_flush_fua = (bio->bi_rw & (REQ_FLUSH | REQ_FUA));
783 mdk_rdev_t *blocked_rdev;
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 */
790
791 md_write_start(mddev, bio); /* wait on superblock update early */
792
793 if (bio_data_dir(bio) == WRITE &&
794 bio->bi_sector + bio->bi_size/512 > mddev->suspend_lo &&
795 bio->bi_sector < mddev->suspend_hi) {
796 /* As the suspend_* range is controlled by
797 * userspace, we want an interruptible
798 * wait.
799 */
800 DEFINE_WAIT(w);
801 for (;;) {
802 flush_signals(current);
803 prepare_to_wait(&conf->wait_barrier,
804 &w, TASK_INTERRUPTIBLE);
805 if (bio->bi_sector + bio->bi_size/512 <= mddev->suspend_lo ||
806 bio->bi_sector >= mddev->suspend_hi)
807 break;
808 schedule();
809 }
810 finish_wait(&conf->wait_barrier, &w);
811 }
812
813 wait_barrier(conf);
814
815 bitmap = mddev->bitmap;
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 if (test_bit(WriteMostly, &mirror->rdev->flags) &&
844 bitmap) {
845 /* Reading from a write-mostly device must
846 * take care not to over-take any writes
847 * that are 'behind'
848 */
849 wait_event(bitmap->behind_wait,
850 atomic_read(&bitmap->behind_writes) == 0);
851 }
852 r1_bio->read_disk = rdisk;
853
854 read_bio = bio_clone(bio, GFP_NOIO);
855
856 r1_bio->bios[rdisk] = read_bio;
857
858 read_bio->bi_sector = r1_bio->sector + mirror->rdev->data_offset;
859 read_bio->bi_bdev = mirror->rdev->bdev;
860 read_bio->bi_end_io = raid1_end_read_request;
861 read_bio->bi_rw = READ | do_sync;
862 read_bio->bi_private = r1_bio;
863
864 generic_make_request(read_bio);
865 return 0;
866 }
867
868 /*
869 * WRITE:
870 */
871 /* first select target devices under spinlock and
872 * inc refcount on their rdev. Record them by setting
873 * bios[x] to bio
874 */
875 disks = conf->raid_disks;
876 #if 0
877 { static int first=1;
878 if (first) printk("First Write sector %llu disks %d\n",
879 (unsigned long long)r1_bio->sector, disks);
880 first = 0;
881 }
882 #endif
883 retry_write:
884 blocked_rdev = NULL;
885 rcu_read_lock();
886 for (i = 0; i < disks; i++) {
887 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
888 if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) {
889 atomic_inc(&rdev->nr_pending);
890 blocked_rdev = rdev;
891 break;
892 }
893 if (rdev && !test_bit(Faulty, &rdev->flags)) {
894 atomic_inc(&rdev->nr_pending);
895 if (test_bit(Faulty, &rdev->flags)) {
896 rdev_dec_pending(rdev, mddev);
897 r1_bio->bios[i] = NULL;
898 } else {
899 r1_bio->bios[i] = bio;
900 targets++;
901 }
902 } else
903 r1_bio->bios[i] = NULL;
904 }
905 rcu_read_unlock();
906
907 if (unlikely(blocked_rdev)) {
908 /* Wait for this device to become unblocked */
909 int j;
910
911 for (j = 0; j < i; j++)
912 if (r1_bio->bios[j])
913 rdev_dec_pending(conf->mirrors[j].rdev, mddev);
914
915 allow_barrier(conf);
916 md_wait_for_blocked_rdev(blocked_rdev, mddev);
917 wait_barrier(conf);
918 goto retry_write;
919 }
920
921 BUG_ON(targets == 0); /* we never fail the last device */
922
923 if (targets < conf->raid_disks) {
924 /* array is degraded, we will not clear the bitmap
925 * on I/O completion (see raid1_end_write_request) */
926 set_bit(R1BIO_Degraded, &r1_bio->state);
927 }
928
929 /* do behind I/O ?
930 * Not if there are too many, or cannot allocate memory,
931 * or a reader on WriteMostly is waiting for behind writes
932 * to flush */
933 if (bitmap &&
934 (atomic_read(&bitmap->behind_writes)
935 < mddev->bitmap_info.max_write_behind) &&
936 !waitqueue_active(&bitmap->behind_wait) &&
937 (behind_pages = alloc_behind_pages(bio)) != NULL)
938 set_bit(R1BIO_BehindIO, &r1_bio->state);
939
940 atomic_set(&r1_bio->remaining, 0);
941 atomic_set(&r1_bio->behind_remaining, 0);
942
943 bio_list_init(&bl);
944 for (i = 0; i < disks; i++) {
945 struct bio *mbio;
946 if (!r1_bio->bios[i])
947 continue;
948
949 mbio = bio_clone(bio, GFP_NOIO);
950 r1_bio->bios[i] = mbio;
951
952 mbio->bi_sector = r1_bio->sector + conf->mirrors[i].rdev->data_offset;
953 mbio->bi_bdev = conf->mirrors[i].rdev->bdev;
954 mbio->bi_end_io = raid1_end_write_request;
955 mbio->bi_rw = WRITE | do_flush_fua | do_sync;
956 mbio->bi_private = r1_bio;
957
958 if (behind_pages) {
959 struct bio_vec *bvec;
960 int j;
961
962 /* Yes, I really want the '__' version so that
963 * we clear any unused pointer in the io_vec, rather
964 * than leave them unchanged. This is important
965 * because when we come to free the pages, we won't
966 * know the originial bi_idx, so we just free
967 * them all
968 */
969 __bio_for_each_segment(bvec, mbio, j, 0)
970 bvec->bv_page = behind_pages[j];
971 if (test_bit(WriteMostly, &conf->mirrors[i].rdev->flags))
972 atomic_inc(&r1_bio->behind_remaining);
973 }
974
975 atomic_inc(&r1_bio->remaining);
976
977 bio_list_add(&bl, mbio);
978 }
979 kfree(behind_pages); /* the behind pages are attached to the bios now */
980
981 bitmap_startwrite(bitmap, bio->bi_sector, r1_bio->sectors,
982 test_bit(R1BIO_BehindIO, &r1_bio->state));
983 spin_lock_irqsave(&conf->device_lock, flags);
984 bio_list_merge(&conf->pending_bio_list, &bl);
985 bio_list_init(&bl);
986
987 blk_plug_device(mddev->queue);
988 spin_unlock_irqrestore(&conf->device_lock, flags);
989
990 /* In case raid1d snuck into freeze_array */
991 wake_up(&conf->wait_barrier);
992
993 if (do_sync)
994 md_wakeup_thread(mddev->thread);
995 #if 0
996 while ((bio = bio_list_pop(&bl)) != NULL)
997 generic_make_request(bio);
998 #endif
999
1000 return 0;
1001 }
1002
1003 static void status(struct seq_file *seq, mddev_t *mddev)
1004 {
1005 conf_t *conf = mddev->private;
1006 int i;
1007
1008 seq_printf(seq, " [%d/%d] [", conf->raid_disks,
1009 conf->raid_disks - mddev->degraded);
1010 rcu_read_lock();
1011 for (i = 0; i < conf->raid_disks; i++) {
1012 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
1013 seq_printf(seq, "%s",
1014 rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_");
1015 }
1016 rcu_read_unlock();
1017 seq_printf(seq, "]");
1018 }
1019
1020
1021 static void error(mddev_t *mddev, mdk_rdev_t *rdev)
1022 {
1023 char b[BDEVNAME_SIZE];
1024 conf_t *conf = mddev->private;
1025
1026 /*
1027 * If it is not operational, then we have already marked it as dead
1028 * else if it is the last working disks, ignore the error, let the
1029 * next level up know.
1030 * else mark the drive as failed
1031 */
1032 if (test_bit(In_sync, &rdev->flags)
1033 && (conf->raid_disks - mddev->degraded) == 1) {
1034 /*
1035 * Don't fail the drive, act as though we were just a
1036 * normal single drive.
1037 * However don't try a recovery from this drive as
1038 * it is very likely to fail.
1039 */
1040 mddev->recovery_disabled = 1;
1041 return;
1042 }
1043 if (test_and_clear_bit(In_sync, &rdev->flags)) {
1044 unsigned long flags;
1045 spin_lock_irqsave(&conf->device_lock, flags);
1046 mddev->degraded++;
1047 set_bit(Faulty, &rdev->flags);
1048 spin_unlock_irqrestore(&conf->device_lock, flags);
1049 /*
1050 * if recovery is running, make sure it aborts.
1051 */
1052 set_bit(MD_RECOVERY_INTR, &mddev->recovery);
1053 } else
1054 set_bit(Faulty, &rdev->flags);
1055 set_bit(MD_CHANGE_DEVS, &mddev->flags);
1056 printk(KERN_ALERT "md/raid1:%s: Disk failure on %s, disabling device.\n"
1057 KERN_ALERT "md/raid1:%s: Operation continuing on %d devices.\n",
1058 mdname(mddev), bdevname(rdev->bdev, b),
1059 mdname(mddev), conf->raid_disks - mddev->degraded);
1060 }
1061
1062 static void print_conf(conf_t *conf)
1063 {
1064 int i;
1065
1066 printk(KERN_DEBUG "RAID1 conf printout:\n");
1067 if (!conf) {
1068 printk(KERN_DEBUG "(!conf)\n");
1069 return;
1070 }
1071 printk(KERN_DEBUG " --- wd:%d rd:%d\n", conf->raid_disks - conf->mddev->degraded,
1072 conf->raid_disks);
1073
1074 rcu_read_lock();
1075 for (i = 0; i < conf->raid_disks; i++) {
1076 char b[BDEVNAME_SIZE];
1077 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
1078 if (rdev)
1079 printk(KERN_DEBUG " disk %d, wo:%d, o:%d, dev:%s\n",
1080 i, !test_bit(In_sync, &rdev->flags),
1081 !test_bit(Faulty, &rdev->flags),
1082 bdevname(rdev->bdev,b));
1083 }
1084 rcu_read_unlock();
1085 }
1086
1087 static void close_sync(conf_t *conf)
1088 {
1089 wait_barrier(conf);
1090 allow_barrier(conf);
1091
1092 mempool_destroy(conf->r1buf_pool);
1093 conf->r1buf_pool = NULL;
1094 }
1095
1096 static int raid1_spare_active(mddev_t *mddev)
1097 {
1098 int i;
1099 conf_t *conf = mddev->private;
1100 int count = 0;
1101 unsigned long flags;
1102
1103 /*
1104 * Find all failed disks within the RAID1 configuration
1105 * and mark them readable.
1106 * Called under mddev lock, so rcu protection not needed.
1107 */
1108 for (i = 0; i < conf->raid_disks; i++) {
1109 mdk_rdev_t *rdev = conf->mirrors[i].rdev;
1110 if (rdev
1111 && !test_bit(Faulty, &rdev->flags)
1112 && !test_and_set_bit(In_sync, &rdev->flags)) {
1113 count++;
1114 sysfs_notify_dirent(rdev->sysfs_state);
1115 }
1116 }
1117 spin_lock_irqsave(&conf->device_lock, flags);
1118 mddev->degraded -= count;
1119 spin_unlock_irqrestore(&conf->device_lock, flags);
1120
1121 print_conf(conf);
1122 return count;
1123 }
1124
1125
1126 static int raid1_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
1127 {
1128 conf_t *conf = mddev->private;
1129 int err = -EEXIST;
1130 int mirror = 0;
1131 mirror_info_t *p;
1132 int first = 0;
1133 int last = mddev->raid_disks - 1;
1134
1135 if (rdev->raid_disk >= 0)
1136 first = last = rdev->raid_disk;
1137
1138 for (mirror = first; mirror <= last; mirror++)
1139 if ( !(p=conf->mirrors+mirror)->rdev) {
1140
1141 disk_stack_limits(mddev->gendisk, rdev->bdev,
1142 rdev->data_offset << 9);
1143 /* as we don't honour merge_bvec_fn, we must
1144 * never risk violating it, so limit
1145 * ->max_segments to one lying with a single
1146 * page, as a one page request is never in
1147 * violation.
1148 */
1149 if (rdev->bdev->bd_disk->queue->merge_bvec_fn) {
1150 blk_queue_max_segments(mddev->queue, 1);
1151 blk_queue_segment_boundary(mddev->queue,
1152 PAGE_CACHE_SIZE - 1);
1153 }
1154
1155 p->head_position = 0;
1156 rdev->raid_disk = mirror;
1157 err = 0;
1158 /* As all devices are equivalent, we don't need a full recovery
1159 * if this was recently any drive of the array
1160 */
1161 if (rdev->saved_raid_disk < 0)
1162 conf->fullsync = 1;
1163 rcu_assign_pointer(p->rdev, rdev);
1164 break;
1165 }
1166 md_integrity_add_rdev(rdev, mddev);
1167 print_conf(conf);
1168 return err;
1169 }
1170
1171 static int raid1_remove_disk(mddev_t *mddev, int number)
1172 {
1173 conf_t *conf = mddev->private;
1174 int err = 0;
1175 mdk_rdev_t *rdev;
1176 mirror_info_t *p = conf->mirrors+ number;
1177
1178 print_conf(conf);
1179 rdev = p->rdev;
1180 if (rdev) {
1181 if (test_bit(In_sync, &rdev->flags) ||
1182 atomic_read(&rdev->nr_pending)) {
1183 err = -EBUSY;
1184 goto abort;
1185 }
1186 /* Only remove non-faulty devices is recovery
1187 * is not possible.
1188 */
1189 if (!test_bit(Faulty, &rdev->flags) &&
1190 mddev->degraded < conf->raid_disks) {
1191 err = -EBUSY;
1192 goto abort;
1193 }
1194 p->rdev = NULL;
1195 synchronize_rcu();
1196 if (atomic_read(&rdev->nr_pending)) {
1197 /* lost the race, try later */
1198 err = -EBUSY;
1199 p->rdev = rdev;
1200 goto abort;
1201 }
1202 md_integrity_register(mddev);
1203 }
1204 abort:
1205
1206 print_conf(conf);
1207 return err;
1208 }
1209
1210
1211 static void end_sync_read(struct bio *bio, int error)
1212 {
1213 r1bio_t *r1_bio = bio->bi_private;
1214 int i;
1215
1216 for (i=r1_bio->mddev->raid_disks; i--; )
1217 if (r1_bio->bios[i] == bio)
1218 break;
1219 BUG_ON(i < 0);
1220 update_head_pos(i, r1_bio);
1221 /*
1222 * we have read a block, now it needs to be re-written,
1223 * or re-read if the read failed.
1224 * We don't do much here, just schedule handling by raid1d
1225 */
1226 if (test_bit(BIO_UPTODATE, &bio->bi_flags))
1227 set_bit(R1BIO_Uptodate, &r1_bio->state);
1228
1229 if (atomic_dec_and_test(&r1_bio->remaining))
1230 reschedule_retry(r1_bio);
1231 }
1232
1233 static void end_sync_write(struct bio *bio, int error)
1234 {
1235 int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
1236 r1bio_t *r1_bio = bio->bi_private;
1237 mddev_t *mddev = r1_bio->mddev;
1238 conf_t *conf = mddev->private;
1239 int i;
1240 int mirror=0;
1241
1242 for (i = 0; i < conf->raid_disks; i++)
1243 if (r1_bio->bios[i] == bio) {
1244 mirror = i;
1245 break;
1246 }
1247 if (!uptodate) {
1248 int sync_blocks = 0;
1249 sector_t s = r1_bio->sector;
1250 long sectors_to_go = r1_bio->sectors;
1251 /* make sure these bits doesn't get cleared. */
1252 do {
1253 bitmap_end_sync(mddev->bitmap, s,
1254 &sync_blocks, 1);
1255 s += sync_blocks;
1256 sectors_to_go -= sync_blocks;
1257 } while (sectors_to_go > 0);
1258 md_error(mddev, conf->mirrors[mirror].rdev);
1259 }
1260
1261 update_head_pos(mirror, r1_bio);
1262
1263 if (atomic_dec_and_test(&r1_bio->remaining)) {
1264 sector_t s = r1_bio->sectors;
1265 put_buf(r1_bio);
1266 md_done_sync(mddev, s, uptodate);
1267 }
1268 }
1269
1270 static void sync_request_write(mddev_t *mddev, r1bio_t *r1_bio)
1271 {
1272 conf_t *conf = mddev->private;
1273 int i;
1274 int disks = conf->raid_disks;
1275 struct bio *bio, *wbio;
1276
1277 bio = r1_bio->bios[r1_bio->read_disk];
1278
1279
1280 if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
1281 /* We have read all readable devices. If we haven't
1282 * got the block, then there is no hope left.
1283 * If we have, then we want to do a comparison
1284 * and skip the write if everything is the same.
1285 * If any blocks failed to read, then we need to
1286 * attempt an over-write
1287 */
1288 int primary;
1289 if (!test_bit(R1BIO_Uptodate, &r1_bio->state)) {
1290 for (i=0; i<mddev->raid_disks; i++)
1291 if (r1_bio->bios[i]->bi_end_io == end_sync_read)
1292 md_error(mddev, conf->mirrors[i].rdev);
1293
1294 md_done_sync(mddev, r1_bio->sectors, 1);
1295 put_buf(r1_bio);
1296 return;
1297 }
1298 for (primary=0; primary<mddev->raid_disks; primary++)
1299 if (r1_bio->bios[primary]->bi_end_io == end_sync_read &&
1300 test_bit(BIO_UPTODATE, &r1_bio->bios[primary]->bi_flags)) {
1301 r1_bio->bios[primary]->bi_end_io = NULL;
1302 rdev_dec_pending(conf->mirrors[primary].rdev, mddev);
1303 break;
1304 }
1305 r1_bio->read_disk = primary;
1306 for (i=0; i<mddev->raid_disks; i++)
1307 if (r1_bio->bios[i]->bi_end_io == end_sync_read) {
1308 int j;
1309 int vcnt = r1_bio->sectors >> (PAGE_SHIFT- 9);
1310 struct bio *pbio = r1_bio->bios[primary];
1311 struct bio *sbio = r1_bio->bios[i];
1312
1313 if (test_bit(BIO_UPTODATE, &sbio->bi_flags)) {
1314 for (j = vcnt; j-- ; ) {
1315 struct page *p, *s;
1316 p = pbio->bi_io_vec[j].bv_page;
1317 s = sbio->bi_io_vec[j].bv_page;
1318 if (memcmp(page_address(p),
1319 page_address(s),
1320 PAGE_SIZE))
1321 break;
1322 }
1323 } else
1324 j = 0;
1325 if (j >= 0)
1326 mddev->resync_mismatches += r1_bio->sectors;
1327 if (j < 0 || (test_bit(MD_RECOVERY_CHECK, &mddev->recovery)
1328 && test_bit(BIO_UPTODATE, &sbio->bi_flags))) {
1329 sbio->bi_end_io = NULL;
1330 rdev_dec_pending(conf->mirrors[i].rdev, mddev);
1331 } else {
1332 /* fixup the bio for reuse */
1333 int size;
1334 sbio->bi_vcnt = vcnt;
1335 sbio->bi_size = r1_bio->sectors << 9;
1336 sbio->bi_idx = 0;
1337 sbio->bi_phys_segments = 0;
1338 sbio->bi_flags &= ~(BIO_POOL_MASK - 1);
1339 sbio->bi_flags |= 1 << BIO_UPTODATE;
1340 sbio->bi_next = NULL;
1341 sbio->bi_sector = r1_bio->sector +
1342 conf->mirrors[i].rdev->data_offset;
1343 sbio->bi_bdev = conf->mirrors[i].rdev->bdev;
1344 size = sbio->bi_size;
1345 for (j = 0; j < vcnt ; j++) {
1346 struct bio_vec *bi;
1347 bi = &sbio->bi_io_vec[j];
1348 bi->bv_offset = 0;
1349 if (size > PAGE_SIZE)
1350 bi->bv_len = PAGE_SIZE;
1351 else
1352 bi->bv_len = size;
1353 size -= PAGE_SIZE;
1354 memcpy(page_address(bi->bv_page),
1355 page_address(pbio->bi_io_vec[j].bv_page),
1356 PAGE_SIZE);
1357 }
1358
1359 }
1360 }
1361 }
1362 if (!test_bit(R1BIO_Uptodate, &r1_bio->state)) {
1363 /* ouch - failed to read all of that.
1364 * Try some synchronous reads of other devices to get
1365 * good data, much like with normal read errors. Only
1366 * read into the pages we already have so we don't
1367 * need to re-issue the read request.
1368 * We don't need to freeze the array, because being in an
1369 * active sync request, there is no normal IO, and
1370 * no overlapping syncs.
1371 */
1372 sector_t sect = r1_bio->sector;
1373 int sectors = r1_bio->sectors;
1374 int idx = 0;
1375
1376 while(sectors) {
1377 int s = sectors;
1378 int d = r1_bio->read_disk;
1379 int success = 0;
1380 mdk_rdev_t *rdev;
1381
1382 if (s > (PAGE_SIZE>>9))
1383 s = PAGE_SIZE >> 9;
1384 do {
1385 if (r1_bio->bios[d]->bi_end_io == end_sync_read) {
1386 /* No rcu protection needed here devices
1387 * can only be removed when no resync is
1388 * active, and resync is currently active
1389 */
1390 rdev = conf->mirrors[d].rdev;
1391 if (sync_page_io(rdev->bdev,
1392 sect + rdev->data_offset,
1393 s<<9,
1394 bio->bi_io_vec[idx].bv_page,
1395 READ)) {
1396 success = 1;
1397 break;
1398 }
1399 }
1400 d++;
1401 if (d == conf->raid_disks)
1402 d = 0;
1403 } while (!success && d != r1_bio->read_disk);
1404
1405 if (success) {
1406 int start = d;
1407 /* write it back and re-read */
1408 set_bit(R1BIO_Uptodate, &r1_bio->state);
1409 while (d != r1_bio->read_disk) {
1410 if (d == 0)
1411 d = conf->raid_disks;
1412 d--;
1413 if (r1_bio->bios[d]->bi_end_io != end_sync_read)
1414 continue;
1415 rdev = conf->mirrors[d].rdev;
1416 atomic_add(s, &rdev->corrected_errors);
1417 if (sync_page_io(rdev->bdev,
1418 sect + rdev->data_offset,
1419 s<<9,
1420 bio->bi_io_vec[idx].bv_page,
1421 WRITE) == 0)
1422 md_error(mddev, rdev);
1423 }
1424 d = start;
1425 while (d != r1_bio->read_disk) {
1426 if (d == 0)
1427 d = conf->raid_disks;
1428 d--;
1429 if (r1_bio->bios[d]->bi_end_io != end_sync_read)
1430 continue;
1431 rdev = conf->mirrors[d].rdev;
1432 if (sync_page_io(rdev->bdev,
1433 sect + rdev->data_offset,
1434 s<<9,
1435 bio->bi_io_vec[idx].bv_page,
1436 READ) == 0)
1437 md_error(mddev, rdev);
1438 }
1439 } else {
1440 char b[BDEVNAME_SIZE];
1441 /* Cannot read from anywhere, array is toast */
1442 md_error(mddev, conf->mirrors[r1_bio->read_disk].rdev);
1443 printk(KERN_ALERT "md/raid1:%s: %s: unrecoverable I/O read error"
1444 " for block %llu\n",
1445 mdname(mddev),
1446 bdevname(bio->bi_bdev, b),
1447 (unsigned long long)r1_bio->sector);
1448 md_done_sync(mddev, r1_bio->sectors, 0);
1449 put_buf(r1_bio);
1450 return;
1451 }
1452 sectors -= s;
1453 sect += s;
1454 idx ++;
1455 }
1456 }
1457
1458 /*
1459 * schedule writes
1460 */
1461 atomic_set(&r1_bio->remaining, 1);
1462 for (i = 0; i < disks ; i++) {
1463 wbio = r1_bio->bios[i];
1464 if (wbio->bi_end_io == NULL ||
1465 (wbio->bi_end_io == end_sync_read &&
1466 (i == r1_bio->read_disk ||
1467 !test_bit(MD_RECOVERY_SYNC, &mddev->recovery))))
1468 continue;
1469
1470 wbio->bi_rw = WRITE;
1471 wbio->bi_end_io = end_sync_write;
1472 atomic_inc(&r1_bio->remaining);
1473 md_sync_acct(conf->mirrors[i].rdev->bdev, wbio->bi_size >> 9);
1474
1475 generic_make_request(wbio);
1476 }
1477
1478 if (atomic_dec_and_test(&r1_bio->remaining)) {
1479 /* if we're here, all write(s) have completed, so clean up */
1480 md_done_sync(mddev, r1_bio->sectors, 1);
1481 put_buf(r1_bio);
1482 }
1483 }
1484
1485 /*
1486 * This is a kernel thread which:
1487 *
1488 * 1. Retries failed read operations on working mirrors.
1489 * 2. Updates the raid superblock when problems encounter.
1490 * 3. Performs writes following reads for array syncronising.
1491 */
1492
1493 static void fix_read_error(conf_t *conf, int read_disk,
1494 sector_t sect, int sectors)
1495 {
1496 mddev_t *mddev = conf->mddev;
1497 while(sectors) {
1498 int s = sectors;
1499 int d = read_disk;
1500 int success = 0;
1501 int start;
1502 mdk_rdev_t *rdev;
1503
1504 if (s > (PAGE_SIZE>>9))
1505 s = PAGE_SIZE >> 9;
1506
1507 do {
1508 /* Note: no rcu protection needed here
1509 * as this is synchronous in the raid1d thread
1510 * which is the thread that might remove
1511 * a device. If raid1d ever becomes multi-threaded....
1512 */
1513 rdev = conf->mirrors[d].rdev;
1514 if (rdev &&
1515 test_bit(In_sync, &rdev->flags) &&
1516 sync_page_io(rdev->bdev,
1517 sect + rdev->data_offset,
1518 s<<9,
1519 conf->tmppage, READ))
1520 success = 1;
1521 else {
1522 d++;
1523 if (d == conf->raid_disks)
1524 d = 0;
1525 }
1526 } while (!success && d != read_disk);
1527
1528 if (!success) {
1529 /* Cannot read from anywhere -- bye bye array */
1530 md_error(mddev, conf->mirrors[read_disk].rdev);
1531 break;
1532 }
1533 /* write it back and re-read */
1534 start = d;
1535 while (d != read_disk) {
1536 if (d==0)
1537 d = conf->raid_disks;
1538 d--;
1539 rdev = conf->mirrors[d].rdev;
1540 if (rdev &&
1541 test_bit(In_sync, &rdev->flags)) {
1542 if (sync_page_io(rdev->bdev,
1543 sect + rdev->data_offset,
1544 s<<9, conf->tmppage, WRITE)
1545 == 0)
1546 /* Well, this device is dead */
1547 md_error(mddev, rdev);
1548 }
1549 }
1550 d = start;
1551 while (d != read_disk) {
1552 char b[BDEVNAME_SIZE];
1553 if (d==0)
1554 d = conf->raid_disks;
1555 d--;
1556 rdev = conf->mirrors[d].rdev;
1557 if (rdev &&
1558 test_bit(In_sync, &rdev->flags)) {
1559 if (sync_page_io(rdev->bdev,
1560 sect + rdev->data_offset,
1561 s<<9, conf->tmppage, READ)
1562 == 0)
1563 /* Well, this device is dead */
1564 md_error(mddev, rdev);
1565 else {
1566 atomic_add(s, &rdev->corrected_errors);
1567 printk(KERN_INFO
1568 "md/raid1:%s: read error corrected "
1569 "(%d sectors at %llu on %s)\n",
1570 mdname(mddev), s,
1571 (unsigned long long)(sect +
1572 rdev->data_offset),
1573 bdevname(rdev->bdev, b));
1574 }
1575 }
1576 }
1577 sectors -= s;
1578 sect += s;
1579 }
1580 }
1581
1582 static void raid1d(mddev_t *mddev)
1583 {
1584 r1bio_t *r1_bio;
1585 struct bio *bio;
1586 unsigned long flags;
1587 conf_t *conf = mddev->private;
1588 struct list_head *head = &conf->retry_list;
1589 int unplug=0;
1590 mdk_rdev_t *rdev;
1591
1592 md_check_recovery(mddev);
1593
1594 for (;;) {
1595 char b[BDEVNAME_SIZE];
1596
1597 unplug += flush_pending_writes(conf);
1598
1599 spin_lock_irqsave(&conf->device_lock, flags);
1600 if (list_empty(head)) {
1601 spin_unlock_irqrestore(&conf->device_lock, flags);
1602 break;
1603 }
1604 r1_bio = list_entry(head->prev, r1bio_t, retry_list);
1605 list_del(head->prev);
1606 conf->nr_queued--;
1607 spin_unlock_irqrestore(&conf->device_lock, flags);
1608
1609 mddev = r1_bio->mddev;
1610 conf = mddev->private;
1611 if (test_bit(R1BIO_IsSync, &r1_bio->state)) {
1612 sync_request_write(mddev, r1_bio);
1613 unplug = 1;
1614 } else {
1615 int disk;
1616
1617 /* we got a read error. Maybe the drive is bad. Maybe just
1618 * the block and we can fix it.
1619 * We freeze all other IO, and try reading the block from
1620 * other devices. When we find one, we re-write
1621 * and check it that fixes the read error.
1622 * This is all done synchronously while the array is
1623 * frozen
1624 */
1625 if (mddev->ro == 0) {
1626 freeze_array(conf);
1627 fix_read_error(conf, r1_bio->read_disk,
1628 r1_bio->sector,
1629 r1_bio->sectors);
1630 unfreeze_array(conf);
1631 } else
1632 md_error(mddev,
1633 conf->mirrors[r1_bio->read_disk].rdev);
1634
1635 bio = r1_bio->bios[r1_bio->read_disk];
1636 if ((disk=read_balance(conf, r1_bio)) == -1) {
1637 printk(KERN_ALERT "md/raid1:%s: %s: unrecoverable I/O"
1638 " read error for block %llu\n",
1639 mdname(mddev),
1640 bdevname(bio->bi_bdev,b),
1641 (unsigned long long)r1_bio->sector);
1642 raid_end_bio_io(r1_bio);
1643 } else {
1644 const unsigned long do_sync = r1_bio->master_bio->bi_rw & REQ_SYNC;
1645 r1_bio->bios[r1_bio->read_disk] =
1646 mddev->ro ? IO_BLOCKED : NULL;
1647 r1_bio->read_disk = disk;
1648 bio_put(bio);
1649 bio = bio_clone(r1_bio->master_bio, GFP_NOIO);
1650 r1_bio->bios[r1_bio->read_disk] = bio;
1651 rdev = conf->mirrors[disk].rdev;
1652 if (printk_ratelimit())
1653 printk(KERN_ERR "md/raid1:%s: redirecting sector %llu to"
1654 " other mirror: %s\n",
1655 mdname(mddev),
1656 (unsigned long long)r1_bio->sector,
1657 bdevname(rdev->bdev,b));
1658 bio->bi_sector = r1_bio->sector + rdev->data_offset;
1659 bio->bi_bdev = rdev->bdev;
1660 bio->bi_end_io = raid1_end_read_request;
1661 bio->bi_rw = READ | do_sync;
1662 bio->bi_private = r1_bio;
1663 unplug = 1;
1664 generic_make_request(bio);
1665 }
1666 }
1667 cond_resched();
1668 }
1669 if (unplug)
1670 unplug_slaves(mddev);
1671 }
1672
1673
1674 static int init_resync(conf_t *conf)
1675 {
1676 int buffs;
1677
1678 buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE;
1679 BUG_ON(conf->r1buf_pool);
1680 conf->r1buf_pool = mempool_create(buffs, r1buf_pool_alloc, r1buf_pool_free,
1681 conf->poolinfo);
1682 if (!conf->r1buf_pool)
1683 return -ENOMEM;
1684 conf->next_resync = 0;
1685 return 0;
1686 }
1687
1688 /*
1689 * perform a "sync" on one "block"
1690 *
1691 * We need to make sure that no normal I/O request - particularly write
1692 * requests - conflict with active sync requests.
1693 *
1694 * This is achieved by tracking pending requests and a 'barrier' concept
1695 * that can be installed to exclude normal IO requests.
1696 */
1697
1698 static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster)
1699 {
1700 conf_t *conf = mddev->private;
1701 r1bio_t *r1_bio;
1702 struct bio *bio;
1703 sector_t max_sector, nr_sectors;
1704 int disk = -1;
1705 int i;
1706 int wonly = -1;
1707 int write_targets = 0, read_targets = 0;
1708 int sync_blocks;
1709 int still_degraded = 0;
1710
1711 if (!conf->r1buf_pool)
1712 if (init_resync(conf))
1713 return 0;
1714
1715 max_sector = mddev->dev_sectors;
1716 if (sector_nr >= max_sector) {
1717 /* If we aborted, we need to abort the
1718 * sync on the 'current' bitmap chunk (there will
1719 * only be one in raid1 resync.
1720 * We can find the current addess in mddev->curr_resync
1721 */
1722 if (mddev->curr_resync < max_sector) /* aborted */
1723 bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
1724 &sync_blocks, 1);
1725 else /* completed sync */
1726 conf->fullsync = 0;
1727
1728 bitmap_close_sync(mddev->bitmap);
1729 close_sync(conf);
1730 return 0;
1731 }
1732
1733 if (mddev->bitmap == NULL &&
1734 mddev->recovery_cp == MaxSector &&
1735 !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
1736 conf->fullsync == 0) {
1737 *skipped = 1;
1738 return max_sector - sector_nr;
1739 }
1740 /* before building a request, check if we can skip these blocks..
1741 * This call the bitmap_start_sync doesn't actually record anything
1742 */
1743 if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
1744 !conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
1745 /* We can skip this block, and probably several more */
1746 *skipped = 1;
1747 return sync_blocks;
1748 }
1749 /*
1750 * If there is non-resync activity waiting for a turn,
1751 * and resync is going fast enough,
1752 * then let it though before starting on this new sync request.
1753 */
1754 if (!go_faster && conf->nr_waiting)
1755 msleep_interruptible(1000);
1756
1757 bitmap_cond_end_sync(mddev->bitmap, sector_nr);
1758 raise_barrier(conf);
1759
1760 conf->next_resync = sector_nr;
1761
1762 r1_bio = mempool_alloc(conf->r1buf_pool, GFP_NOIO);
1763 rcu_read_lock();
1764 /*
1765 * If we get a correctably read error during resync or recovery,
1766 * we might want to read from a different device. So we
1767 * flag all drives that could conceivably be read from for READ,
1768 * and any others (which will be non-In_sync devices) for WRITE.
1769 * If a read fails, we try reading from something else for which READ
1770 * is OK.
1771 */
1772
1773 r1_bio->mddev = mddev;
1774 r1_bio->sector = sector_nr;
1775 r1_bio->state = 0;
1776 set_bit(R1BIO_IsSync, &r1_bio->state);
1777
1778 for (i=0; i < conf->raid_disks; i++) {
1779 mdk_rdev_t *rdev;
1780 bio = r1_bio->bios[i];
1781
1782 /* take from bio_init */
1783 bio->bi_next = NULL;
1784 bio->bi_flags |= 1 << BIO_UPTODATE;
1785 bio->bi_rw = READ;
1786 bio->bi_vcnt = 0;
1787 bio->bi_idx = 0;
1788 bio->bi_phys_segments = 0;
1789 bio->bi_size = 0;
1790 bio->bi_end_io = NULL;
1791 bio->bi_private = NULL;
1792
1793 rdev = rcu_dereference(conf->mirrors[i].rdev);
1794 if (rdev == NULL ||
1795 test_bit(Faulty, &rdev->flags)) {
1796 still_degraded = 1;
1797 continue;
1798 } else if (!test_bit(In_sync, &rdev->flags)) {
1799 bio->bi_rw = WRITE;
1800 bio->bi_end_io = end_sync_write;
1801 write_targets ++;
1802 } else {
1803 /* may need to read from here */
1804 bio->bi_rw = READ;
1805 bio->bi_end_io = end_sync_read;
1806 if (test_bit(WriteMostly, &rdev->flags)) {
1807 if (wonly < 0)
1808 wonly = i;
1809 } else {
1810 if (disk < 0)
1811 disk = i;
1812 }
1813 read_targets++;
1814 }
1815 atomic_inc(&rdev->nr_pending);
1816 bio->bi_sector = sector_nr + rdev->data_offset;
1817 bio->bi_bdev = rdev->bdev;
1818 bio->bi_private = r1_bio;
1819 }
1820 rcu_read_unlock();
1821 if (disk < 0)
1822 disk = wonly;
1823 r1_bio->read_disk = disk;
1824
1825 if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) && read_targets > 0)
1826 /* extra read targets are also write targets */
1827 write_targets += read_targets-1;
1828
1829 if (write_targets == 0 || read_targets == 0) {
1830 /* There is nowhere to write, so all non-sync
1831 * drives must be failed - so we are finished
1832 */
1833 sector_t rv = max_sector - sector_nr;
1834 *skipped = 1;
1835 put_buf(r1_bio);
1836 return rv;
1837 }
1838
1839 if (max_sector > mddev->resync_max)
1840 max_sector = mddev->resync_max; /* Don't do IO beyond here */
1841 nr_sectors = 0;
1842 sync_blocks = 0;
1843 do {
1844 struct page *page;
1845 int len = PAGE_SIZE;
1846 if (sector_nr + (len>>9) > max_sector)
1847 len = (max_sector - sector_nr) << 9;
1848 if (len == 0)
1849 break;
1850 if (sync_blocks == 0) {
1851 if (!bitmap_start_sync(mddev->bitmap, sector_nr,
1852 &sync_blocks, still_degraded) &&
1853 !conf->fullsync &&
1854 !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
1855 break;
1856 BUG_ON(sync_blocks < (PAGE_SIZE>>9));
1857 if (len > (sync_blocks<<9))
1858 len = sync_blocks<<9;
1859 }
1860
1861 for (i=0 ; i < conf->raid_disks; i++) {
1862 bio = r1_bio->bios[i];
1863 if (bio->bi_end_io) {
1864 page = bio->bi_io_vec[bio->bi_vcnt].bv_page;
1865 if (bio_add_page(bio, page, len, 0) == 0) {
1866 /* stop here */
1867 bio->bi_io_vec[bio->bi_vcnt].bv_page = page;
1868 while (i > 0) {
1869 i--;
1870 bio = r1_bio->bios[i];
1871 if (bio->bi_end_io==NULL)
1872 continue;
1873 /* remove last page from this bio */
1874 bio->bi_vcnt--;
1875 bio->bi_size -= len;
1876 bio->bi_flags &= ~(1<< BIO_SEG_VALID);
1877 }
1878 goto bio_full;
1879 }
1880 }
1881 }
1882 nr_sectors += len>>9;
1883 sector_nr += len>>9;
1884 sync_blocks -= (len>>9);
1885 } while (r1_bio->bios[disk]->bi_vcnt < RESYNC_PAGES);
1886 bio_full:
1887 r1_bio->sectors = nr_sectors;
1888
1889 /* For a user-requested sync, we read all readable devices and do a
1890 * compare
1891 */
1892 if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
1893 atomic_set(&r1_bio->remaining, read_targets);
1894 for (i=0; i<conf->raid_disks; i++) {
1895 bio = r1_bio->bios[i];
1896 if (bio->bi_end_io == end_sync_read) {
1897 md_sync_acct(bio->bi_bdev, nr_sectors);
1898 generic_make_request(bio);
1899 }
1900 }
1901 } else {
1902 atomic_set(&r1_bio->remaining, 1);
1903 bio = r1_bio->bios[r1_bio->read_disk];
1904 md_sync_acct(bio->bi_bdev, nr_sectors);
1905 generic_make_request(bio);
1906
1907 }
1908 return nr_sectors;
1909 }
1910
1911 static sector_t raid1_size(mddev_t *mddev, sector_t sectors, int raid_disks)
1912 {
1913 if (sectors)
1914 return sectors;
1915
1916 return mddev->dev_sectors;
1917 }
1918
1919 static conf_t *setup_conf(mddev_t *mddev)
1920 {
1921 conf_t *conf;
1922 int i;
1923 mirror_info_t *disk;
1924 mdk_rdev_t *rdev;
1925 int err = -ENOMEM;
1926
1927 conf = kzalloc(sizeof(conf_t), GFP_KERNEL);
1928 if (!conf)
1929 goto abort;
1930
1931 conf->mirrors = kzalloc(sizeof(struct mirror_info)*mddev->raid_disks,
1932 GFP_KERNEL);
1933 if (!conf->mirrors)
1934 goto abort;
1935
1936 conf->tmppage = alloc_page(GFP_KERNEL);
1937 if (!conf->tmppage)
1938 goto abort;
1939
1940 conf->poolinfo = kzalloc(sizeof(*conf->poolinfo), GFP_KERNEL);
1941 if (!conf->poolinfo)
1942 goto abort;
1943 conf->poolinfo->raid_disks = mddev->raid_disks;
1944 conf->r1bio_pool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc,
1945 r1bio_pool_free,
1946 conf->poolinfo);
1947 if (!conf->r1bio_pool)
1948 goto abort;
1949
1950 conf->poolinfo->mddev = mddev;
1951
1952 spin_lock_init(&conf->device_lock);
1953 list_for_each_entry(rdev, &mddev->disks, same_set) {
1954 int disk_idx = rdev->raid_disk;
1955 if (disk_idx >= mddev->raid_disks
1956 || disk_idx < 0)
1957 continue;
1958 disk = conf->mirrors + disk_idx;
1959
1960 disk->rdev = rdev;
1961
1962 disk->head_position = 0;
1963 }
1964 conf->raid_disks = mddev->raid_disks;
1965 conf->mddev = mddev;
1966 INIT_LIST_HEAD(&conf->retry_list);
1967
1968 spin_lock_init(&conf->resync_lock);
1969 init_waitqueue_head(&conf->wait_barrier);
1970
1971 bio_list_init(&conf->pending_bio_list);
1972 bio_list_init(&conf->flushing_bio_list);
1973
1974 conf->last_used = -1;
1975 for (i = 0; i < conf->raid_disks; i++) {
1976
1977 disk = conf->mirrors + i;
1978
1979 if (!disk->rdev ||
1980 !test_bit(In_sync, &disk->rdev->flags)) {
1981 disk->head_position = 0;
1982 if (disk->rdev)
1983 conf->fullsync = 1;
1984 } else if (conf->last_used < 0)
1985 /*
1986 * The first working device is used as a
1987 * starting point to read balancing.
1988 */
1989 conf->last_used = i;
1990 }
1991
1992 err = -EIO;
1993 if (conf->last_used < 0) {
1994 printk(KERN_ERR "md/raid1:%s: no operational mirrors\n",
1995 mdname(mddev));
1996 goto abort;
1997 }
1998 err = -ENOMEM;
1999 conf->thread = md_register_thread(raid1d, mddev, NULL);
2000 if (!conf->thread) {
2001 printk(KERN_ERR
2002 "md/raid1:%s: couldn't allocate thread\n",
2003 mdname(mddev));
2004 goto abort;
2005 }
2006
2007 return conf;
2008
2009 abort:
2010 if (conf) {
2011 if (conf->r1bio_pool)
2012 mempool_destroy(conf->r1bio_pool);
2013 kfree(conf->mirrors);
2014 safe_put_page(conf->tmppage);
2015 kfree(conf->poolinfo);
2016 kfree(conf);
2017 }
2018 return ERR_PTR(err);
2019 }
2020
2021 static int run(mddev_t *mddev)
2022 {
2023 conf_t *conf;
2024 int i;
2025 mdk_rdev_t *rdev;
2026
2027 if (mddev->level != 1) {
2028 printk(KERN_ERR "md/raid1:%s: raid level not set to mirroring (%d)\n",
2029 mdname(mddev), mddev->level);
2030 return -EIO;
2031 }
2032 if (mddev->reshape_position != MaxSector) {
2033 printk(KERN_ERR "md/raid1:%s: reshape_position set but not supported\n",
2034 mdname(mddev));
2035 return -EIO;
2036 }
2037 /*
2038 * copy the already verified devices into our private RAID1
2039 * bookkeeping area. [whatever we allocate in run(),
2040 * should be freed in stop()]
2041 */
2042 if (mddev->private == NULL)
2043 conf = setup_conf(mddev);
2044 else
2045 conf = mddev->private;
2046
2047 if (IS_ERR(conf))
2048 return PTR_ERR(conf);
2049
2050 mddev->queue->queue_lock = &conf->device_lock;
2051 list_for_each_entry(rdev, &mddev->disks, same_set) {
2052 disk_stack_limits(mddev->gendisk, rdev->bdev,
2053 rdev->data_offset << 9);
2054 /* as we don't honour merge_bvec_fn, we must never risk
2055 * violating it, so limit ->max_segments to 1 lying within
2056 * a single page, as a one page request is never in violation.
2057 */
2058 if (rdev->bdev->bd_disk->queue->merge_bvec_fn) {
2059 blk_queue_max_segments(mddev->queue, 1);
2060 blk_queue_segment_boundary(mddev->queue,
2061 PAGE_CACHE_SIZE - 1);
2062 }
2063 }
2064
2065 mddev->degraded = 0;
2066 for (i=0; i < conf->raid_disks; i++)
2067 if (conf->mirrors[i].rdev == NULL ||
2068 !test_bit(In_sync, &conf->mirrors[i].rdev->flags) ||
2069 test_bit(Faulty, &conf->mirrors[i].rdev->flags))
2070 mddev->degraded++;
2071
2072 if (conf->raid_disks - mddev->degraded == 1)
2073 mddev->recovery_cp = MaxSector;
2074
2075 if (mddev->recovery_cp != MaxSector)
2076 printk(KERN_NOTICE "md/raid1:%s: not clean"
2077 " -- starting background reconstruction\n",
2078 mdname(mddev));
2079 printk(KERN_INFO
2080 "md/raid1:%s: active with %d out of %d mirrors\n",
2081 mdname(mddev), mddev->raid_disks - mddev->degraded,
2082 mddev->raid_disks);
2083
2084 /*
2085 * Ok, everything is just fine now
2086 */
2087 mddev->thread = conf->thread;
2088 conf->thread = NULL;
2089 mddev->private = conf;
2090
2091 md_set_array_sectors(mddev, raid1_size(mddev, 0, 0));
2092
2093 mddev->queue->unplug_fn = raid1_unplug;
2094 mddev->queue->backing_dev_info.congested_fn = raid1_congested;
2095 mddev->queue->backing_dev_info.congested_data = mddev;
2096 md_integrity_register(mddev);
2097 return 0;
2098 }
2099
2100 static int stop(mddev_t *mddev)
2101 {
2102 conf_t *conf = mddev->private;
2103 struct bitmap *bitmap = mddev->bitmap;
2104
2105 /* wait for behind writes to complete */
2106 if (bitmap && atomic_read(&bitmap->behind_writes) > 0) {
2107 printk(KERN_INFO "md/raid1:%s: behind writes in progress - waiting to stop.\n",
2108 mdname(mddev));
2109 /* need to kick something here to make sure I/O goes? */
2110 wait_event(bitmap->behind_wait,
2111 atomic_read(&bitmap->behind_writes) == 0);
2112 }
2113
2114 raise_barrier(conf);
2115 lower_barrier(conf);
2116
2117 md_unregister_thread(mddev->thread);
2118 mddev->thread = NULL;
2119 blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
2120 if (conf->r1bio_pool)
2121 mempool_destroy(conf->r1bio_pool);
2122 kfree(conf->mirrors);
2123 kfree(conf->poolinfo);
2124 kfree(conf);
2125 mddev->private = NULL;
2126 return 0;
2127 }
2128
2129 static int raid1_resize(mddev_t *mddev, sector_t sectors)
2130 {
2131 /* no resync is happening, and there is enough space
2132 * on all devices, so we can resize.
2133 * We need to make sure resync covers any new space.
2134 * If the array is shrinking we should possibly wait until
2135 * any io in the removed space completes, but it hardly seems
2136 * worth it.
2137 */
2138 md_set_array_sectors(mddev, raid1_size(mddev, sectors, 0));
2139 if (mddev->array_sectors > raid1_size(mddev, sectors, 0))
2140 return -EINVAL;
2141 set_capacity(mddev->gendisk, mddev->array_sectors);
2142 revalidate_disk(mddev->gendisk);
2143 if (sectors > mddev->dev_sectors &&
2144 mddev->recovery_cp == MaxSector) {
2145 mddev->recovery_cp = mddev->dev_sectors;
2146 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
2147 }
2148 mddev->dev_sectors = sectors;
2149 mddev->resync_max_sectors = sectors;
2150 return 0;
2151 }
2152
2153 static int raid1_reshape(mddev_t *mddev)
2154 {
2155 /* We need to:
2156 * 1/ resize the r1bio_pool
2157 * 2/ resize conf->mirrors
2158 *
2159 * We allocate a new r1bio_pool if we can.
2160 * Then raise a device barrier and wait until all IO stops.
2161 * Then resize conf->mirrors and swap in the new r1bio pool.
2162 *
2163 * At the same time, we "pack" the devices so that all the missing
2164 * devices have the higher raid_disk numbers.
2165 */
2166 mempool_t *newpool, *oldpool;
2167 struct pool_info *newpoolinfo;
2168 mirror_info_t *newmirrors;
2169 conf_t *conf = mddev->private;
2170 int cnt, raid_disks;
2171 unsigned long flags;
2172 int d, d2, err;
2173
2174 /* Cannot change chunk_size, layout, or level */
2175 if (mddev->chunk_sectors != mddev->new_chunk_sectors ||
2176 mddev->layout != mddev->new_layout ||
2177 mddev->level != mddev->new_level) {
2178 mddev->new_chunk_sectors = mddev->chunk_sectors;
2179 mddev->new_layout = mddev->layout;
2180 mddev->new_level = mddev->level;
2181 return -EINVAL;
2182 }
2183
2184 err = md_allow_write(mddev);
2185 if (err)
2186 return err;
2187
2188 raid_disks = mddev->raid_disks + mddev->delta_disks;
2189
2190 if (raid_disks < conf->raid_disks) {
2191 cnt=0;
2192 for (d= 0; d < conf->raid_disks; d++)
2193 if (conf->mirrors[d].rdev)
2194 cnt++;
2195 if (cnt > raid_disks)
2196 return -EBUSY;
2197 }
2198
2199 newpoolinfo = kmalloc(sizeof(*newpoolinfo), GFP_KERNEL);
2200 if (!newpoolinfo)
2201 return -ENOMEM;
2202 newpoolinfo->mddev = mddev;
2203 newpoolinfo->raid_disks = raid_disks;
2204
2205 newpool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc,
2206 r1bio_pool_free, newpoolinfo);
2207 if (!newpool) {
2208 kfree(newpoolinfo);
2209 return -ENOMEM;
2210 }
2211 newmirrors = kzalloc(sizeof(struct mirror_info) * raid_disks, GFP_KERNEL);
2212 if (!newmirrors) {
2213 kfree(newpoolinfo);
2214 mempool_destroy(newpool);
2215 return -ENOMEM;
2216 }
2217
2218 raise_barrier(conf);
2219
2220 /* ok, everything is stopped */
2221 oldpool = conf->r1bio_pool;
2222 conf->r1bio_pool = newpool;
2223
2224 for (d = d2 = 0; d < conf->raid_disks; d++) {
2225 mdk_rdev_t *rdev = conf->mirrors[d].rdev;
2226 if (rdev && rdev->raid_disk != d2) {
2227 char nm[20];
2228 sprintf(nm, "rd%d", rdev->raid_disk);
2229 sysfs_remove_link(&mddev->kobj, nm);
2230 rdev->raid_disk = d2;
2231 sprintf(nm, "rd%d", rdev->raid_disk);
2232 sysfs_remove_link(&mddev->kobj, nm);
2233 if (sysfs_create_link(&mddev->kobj,
2234 &rdev->kobj, nm))
2235 printk(KERN_WARNING
2236 "md/raid1:%s: cannot register "
2237 "%s\n",
2238 mdname(mddev), nm);
2239 }
2240 if (rdev)
2241 newmirrors[d2++].rdev = rdev;
2242 }
2243 kfree(conf->mirrors);
2244 conf->mirrors = newmirrors;
2245 kfree(conf->poolinfo);
2246 conf->poolinfo = newpoolinfo;
2247
2248 spin_lock_irqsave(&conf->device_lock, flags);
2249 mddev->degraded += (raid_disks - conf->raid_disks);
2250 spin_unlock_irqrestore(&conf->device_lock, flags);
2251 conf->raid_disks = mddev->raid_disks = raid_disks;
2252 mddev->delta_disks = 0;
2253
2254 conf->last_used = 0; /* just make sure it is in-range */
2255 lower_barrier(conf);
2256
2257 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
2258 md_wakeup_thread(mddev->thread);
2259
2260 mempool_destroy(oldpool);
2261 return 0;
2262 }
2263
2264 static void raid1_quiesce(mddev_t *mddev, int state)
2265 {
2266 conf_t *conf = mddev->private;
2267
2268 switch(state) {
2269 case 2: /* wake for suspend */
2270 wake_up(&conf->wait_barrier);
2271 break;
2272 case 1:
2273 raise_barrier(conf);
2274 break;
2275 case 0:
2276 lower_barrier(conf);
2277 break;
2278 }
2279 }
2280
2281 static void *raid1_takeover(mddev_t *mddev)
2282 {
2283 /* raid1 can take over:
2284 * raid5 with 2 devices, any layout or chunk size
2285 */
2286 if (mddev->level == 5 && mddev->raid_disks == 2) {
2287 conf_t *conf;
2288 mddev->new_level = 1;
2289 mddev->new_layout = 0;
2290 mddev->new_chunk_sectors = 0;
2291 conf = setup_conf(mddev);
2292 if (!IS_ERR(conf))
2293 conf->barrier = 1;
2294 return conf;
2295 }
2296 return ERR_PTR(-EINVAL);
2297 }
2298
2299 static struct mdk_personality raid1_personality =
2300 {
2301 .name = "raid1",
2302 .level = 1,
2303 .owner = THIS_MODULE,
2304 .make_request = make_request,
2305 .run = run,
2306 .stop = stop,
2307 .status = status,
2308 .error_handler = error,
2309 .hot_add_disk = raid1_add_disk,
2310 .hot_remove_disk= raid1_remove_disk,
2311 .spare_active = raid1_spare_active,
2312 .sync_request = sync_request,
2313 .resize = raid1_resize,
2314 .size = raid1_size,
2315 .check_reshape = raid1_reshape,
2316 .quiesce = raid1_quiesce,
2317 .takeover = raid1_takeover,
2318 };
2319
2320 static int __init raid_init(void)
2321 {
2322 return register_md_personality(&raid1_personality);
2323 }
2324
2325 static void raid_exit(void)
2326 {
2327 unregister_md_personality(&raid1_personality);
2328 }
2329
2330 module_init(raid_init);
2331 module_exit(raid_exit);
2332 MODULE_LICENSE("GPL");
2333 MODULE_DESCRIPTION("RAID1 (mirroring) personality for MD");
2334 MODULE_ALIAS("md-personality-3"); /* RAID1 */
2335 MODULE_ALIAS("md-raid1");
2336 MODULE_ALIAS("md-level-1");
Linux kernel - Deliverables
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