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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * raid10.c : Multiple Devices driver for Linux
3 *
4 * Copyright (C) 2000-2004 Neil Brown
5 *
6 * RAID-10 support for md.
7 *
8 * Base on code in raid1.c. See raid1.c for futher copyright information.
9 *
10 *
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License as published by
13 * the Free Software Foundation; either version 2, or (at your option)
14 * any later version.
15 *
16 * You should have received a copy of the GNU General Public License
17 * (for example /usr/src/linux/COPYING); if not, write to the Free
18 * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
19 */
20
21#include <linux/raid/raid10.h>
22
23/*
24 * RAID10 provides a combination of RAID0 and RAID1 functionality.
25 * The layout of data is defined by
26 * chunk_size
27 * raid_disks
28 * near_copies (stored in low byte of layout)
29 * far_copies (stored in second byte of layout)
30 *
31 * The data to be stored is divided into chunks using chunksize.
32 * Each device is divided into far_copies sections.
33 * In each section, chunks are laid out in a style similar to raid0, but
34 * near_copies copies of each chunk is stored (each on a different drive).
35 * The starting device for each section is offset near_copies from the starting
36 * device of the previous section.
37 * Thus there are (near_copies*far_copies) of each chunk, and each is on a different
38 * drive.
39 * near_copies and far_copies must be at least one, and their product is at most
40 * raid_disks.
41 */
42
43/*
44 * Number of guaranteed r10bios in case of extreme VM load:
45 */
46#define NR_RAID10_BIOS 256
47
48static void unplug_slaves(mddev_t *mddev);
49
Al Virodd0fc662005-10-07 07:46:04 +010050static void * r10bio_pool_alloc(gfp_t gfp_flags, void *data)
Linus Torvalds1da177e2005-04-16 15:20:36 -070051{
52 conf_t *conf = data;
53 r10bio_t *r10_bio;
54 int size = offsetof(struct r10bio_s, devs[conf->copies]);
55
56 /* allocate a r10bio with room for raid_disks entries in the bios array */
57 r10_bio = kmalloc(size, gfp_flags);
58 if (r10_bio)
59 memset(r10_bio, 0, size);
60 else
61 unplug_slaves(conf->mddev);
62
63 return r10_bio;
64}
65
66static void r10bio_pool_free(void *r10_bio, void *data)
67{
68 kfree(r10_bio);
69}
70
71#define RESYNC_BLOCK_SIZE (64*1024)
72//#define RESYNC_BLOCK_SIZE PAGE_SIZE
73#define RESYNC_SECTORS (RESYNC_BLOCK_SIZE >> 9)
74#define RESYNC_PAGES ((RESYNC_BLOCK_SIZE + PAGE_SIZE-1) / PAGE_SIZE)
75#define RESYNC_WINDOW (2048*1024)
76
77/*
78 * When performing a resync, we need to read and compare, so
79 * we need as many pages are there are copies.
80 * When performing a recovery, we need 2 bios, one for read,
81 * one for write (we recover only one drive per r10buf)
82 *
83 */
Al Virodd0fc662005-10-07 07:46:04 +010084static void * r10buf_pool_alloc(gfp_t gfp_flags, void *data)
Linus Torvalds1da177e2005-04-16 15:20:36 -070085{
86 conf_t *conf = data;
87 struct page *page;
88 r10bio_t *r10_bio;
89 struct bio *bio;
90 int i, j;
91 int nalloc;
92
93 r10_bio = r10bio_pool_alloc(gfp_flags, conf);
94 if (!r10_bio) {
95 unplug_slaves(conf->mddev);
96 return NULL;
97 }
98
99 if (test_bit(MD_RECOVERY_SYNC, &conf->mddev->recovery))
100 nalloc = conf->copies; /* resync */
101 else
102 nalloc = 2; /* recovery */
103
104 /*
105 * Allocate bios.
106 */
107 for (j = nalloc ; j-- ; ) {
108 bio = bio_alloc(gfp_flags, RESYNC_PAGES);
109 if (!bio)
110 goto out_free_bio;
111 r10_bio->devs[j].bio = bio;
112 }
113 /*
114 * Allocate RESYNC_PAGES data pages and attach them
115 * where needed.
116 */
117 for (j = 0 ; j < nalloc; j++) {
118 bio = r10_bio->devs[j].bio;
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 }
126 }
127
128 return r10_bio;
129
130out_free_pages:
131 for ( ; i > 0 ; i--)
132 __free_page(bio->bi_io_vec[i-1].bv_page);
133 while (j--)
134 for (i = 0; i < RESYNC_PAGES ; i++)
135 __free_page(r10_bio->devs[j].bio->bi_io_vec[i].bv_page);
136 j = -1;
137out_free_bio:
138 while ( ++j < nalloc )
139 bio_put(r10_bio->devs[j].bio);
140 r10bio_pool_free(r10_bio, conf);
141 return NULL;
142}
143
144static void r10buf_pool_free(void *__r10_bio, void *data)
145{
146 int i;
147 conf_t *conf = data;
148 r10bio_t *r10bio = __r10_bio;
149 int j;
150
151 for (j=0; j < conf->copies; j++) {
152 struct bio *bio = r10bio->devs[j].bio;
153 if (bio) {
154 for (i = 0; i < RESYNC_PAGES; i++) {
155 __free_page(bio->bi_io_vec[i].bv_page);
156 bio->bi_io_vec[i].bv_page = NULL;
157 }
158 bio_put(bio);
159 }
160 }
161 r10bio_pool_free(r10bio, conf);
162}
163
164static void put_all_bios(conf_t *conf, r10bio_t *r10_bio)
165{
166 int i;
167
168 for (i = 0; i < conf->copies; i++) {
169 struct bio **bio = & r10_bio->devs[i].bio;
170 if (*bio)
171 bio_put(*bio);
172 *bio = NULL;
173 }
174}
175
176static inline void free_r10bio(r10bio_t *r10_bio)
177{
178 unsigned long flags;
179
180 conf_t *conf = mddev_to_conf(r10_bio->mddev);
181
182 /*
183 * Wake up any possible resync thread that waits for the device
184 * to go idle.
185 */
186 spin_lock_irqsave(&conf->resync_lock, flags);
187 if (!--conf->nr_pending) {
188 wake_up(&conf->wait_idle);
189 wake_up(&conf->wait_resume);
190 }
191 spin_unlock_irqrestore(&conf->resync_lock, flags);
192
193 put_all_bios(conf, r10_bio);
194 mempool_free(r10_bio, conf->r10bio_pool);
195}
196
197static inline void put_buf(r10bio_t *r10_bio)
198{
199 conf_t *conf = mddev_to_conf(r10_bio->mddev);
200 unsigned long flags;
201
202 mempool_free(r10_bio, conf->r10buf_pool);
203
204 spin_lock_irqsave(&conf->resync_lock, flags);
205 if (!conf->barrier)
206 BUG();
207 --conf->barrier;
208 wake_up(&conf->wait_resume);
209 wake_up(&conf->wait_idle);
210
211 if (!--conf->nr_pending) {
212 wake_up(&conf->wait_idle);
213 wake_up(&conf->wait_resume);
214 }
215 spin_unlock_irqrestore(&conf->resync_lock, flags);
216}
217
218static void reschedule_retry(r10bio_t *r10_bio)
219{
220 unsigned long flags;
221 mddev_t *mddev = r10_bio->mddev;
222 conf_t *conf = mddev_to_conf(mddev);
223
224 spin_lock_irqsave(&conf->device_lock, flags);
225 list_add(&r10_bio->retry_list, &conf->retry_list);
226 spin_unlock_irqrestore(&conf->device_lock, flags);
227
228 md_wakeup_thread(mddev->thread);
229}
230
231/*
232 * raid_end_bio_io() is called when we have finished servicing a mirrored
233 * operation and are ready to return a success/failure code to the buffer
234 * cache layer.
235 */
236static void raid_end_bio_io(r10bio_t *r10_bio)
237{
238 struct bio *bio = r10_bio->master_bio;
239
240 bio_endio(bio, bio->bi_size,
241 test_bit(R10BIO_Uptodate, &r10_bio->state) ? 0 : -EIO);
242 free_r10bio(r10_bio);
243}
244
245/*
246 * Update disk head position estimator based on IRQ completion info.
247 */
248static inline void update_head_pos(int slot, r10bio_t *r10_bio)
249{
250 conf_t *conf = mddev_to_conf(r10_bio->mddev);
251
252 conf->mirrors[r10_bio->devs[slot].devnum].head_position =
253 r10_bio->devs[slot].addr + (r10_bio->sectors);
254}
255
256static int raid10_end_read_request(struct bio *bio, unsigned int bytes_done, int error)
257{
258 int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
259 r10bio_t * r10_bio = (r10bio_t *)(bio->bi_private);
260 int slot, dev;
261 conf_t *conf = mddev_to_conf(r10_bio->mddev);
262
263 if (bio->bi_size)
264 return 1;
265
266 slot = r10_bio->read_slot;
267 dev = r10_bio->devs[slot].devnum;
268 /*
269 * this branch is our 'one mirror IO has finished' event handler:
270 */
271 if (!uptodate)
272 md_error(r10_bio->mddev, conf->mirrors[dev].rdev);
273 else
274 /*
275 * Set R10BIO_Uptodate in our master bio, so that
276 * we will return a good error code to the higher
277 * levels even if IO on some other mirrored buffer fails.
278 *
279 * The 'master' represents the composite IO operation to
280 * user-side. So if something waits for IO, then it will
281 * wait for the 'master' bio.
282 */
283 set_bit(R10BIO_Uptodate, &r10_bio->state);
284
285 update_head_pos(slot, r10_bio);
286
287 /*
288 * we have only one bio on the read side
289 */
290 if (uptodate)
291 raid_end_bio_io(r10_bio);
292 else {
293 /*
294 * oops, read error:
295 */
296 char b[BDEVNAME_SIZE];
297 if (printk_ratelimit())
298 printk(KERN_ERR "raid10: %s: rescheduling sector %llu\n",
299 bdevname(conf->mirrors[dev].rdev->bdev,b), (unsigned long long)r10_bio->sector);
300 reschedule_retry(r10_bio);
301 }
302
303 rdev_dec_pending(conf->mirrors[dev].rdev, conf->mddev);
304 return 0;
305}
306
307static int raid10_end_write_request(struct bio *bio, unsigned int bytes_done, int error)
308{
309 int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
310 r10bio_t * r10_bio = (r10bio_t *)(bio->bi_private);
311 int slot, dev;
312 conf_t *conf = mddev_to_conf(r10_bio->mddev);
313
314 if (bio->bi_size)
315 return 1;
316
317 for (slot = 0; slot < conf->copies; slot++)
318 if (r10_bio->devs[slot].bio == bio)
319 break;
320 dev = r10_bio->devs[slot].devnum;
321
322 /*
323 * this branch is our 'one mirror IO has finished' event handler:
324 */
325 if (!uptodate)
326 md_error(r10_bio->mddev, conf->mirrors[dev].rdev);
327 else
328 /*
329 * Set R10BIO_Uptodate in our master bio, so that
330 * we will return a good error code for to the higher
331 * levels even if IO on some other mirrored buffer fails.
332 *
333 * The 'master' represents the composite IO operation to
334 * user-side. So if something waits for IO, then it will
335 * wait for the 'master' bio.
336 */
337 set_bit(R10BIO_Uptodate, &r10_bio->state);
338
339 update_head_pos(slot, r10_bio);
340
341 /*
342 *
343 * Let's see if all mirrored write operations have finished
344 * already.
345 */
346 if (atomic_dec_and_test(&r10_bio->remaining)) {
347 md_write_end(r10_bio->mddev);
348 raid_end_bio_io(r10_bio);
349 }
350
351 rdev_dec_pending(conf->mirrors[dev].rdev, conf->mddev);
352 return 0;
353}
354
355
356/*
357 * RAID10 layout manager
358 * Aswell as the chunksize and raid_disks count, there are two
359 * parameters: near_copies and far_copies.
360 * near_copies * far_copies must be <= raid_disks.
361 * Normally one of these will be 1.
362 * If both are 1, we get raid0.
363 * If near_copies == raid_disks, we get raid1.
364 *
365 * Chunks are layed out in raid0 style with near_copies copies of the
366 * first chunk, followed by near_copies copies of the next chunk and
367 * so on.
368 * If far_copies > 1, then after 1/far_copies of the array has been assigned
369 * as described above, we start again with a device offset of near_copies.
370 * So we effectively have another copy of the whole array further down all
371 * the drives, but with blocks on different drives.
372 * With this layout, and block is never stored twice on the one device.
373 *
374 * raid10_find_phys finds the sector offset of a given virtual sector
375 * on each device that it is on. If a block isn't on a device,
376 * that entry in the array is set to MaxSector.
377 *
378 * raid10_find_virt does the reverse mapping, from a device and a
379 * sector offset to a virtual address
380 */
381
382static void raid10_find_phys(conf_t *conf, r10bio_t *r10bio)
383{
384 int n,f;
385 sector_t sector;
386 sector_t chunk;
387 sector_t stripe;
388 int dev;
389
390 int slot = 0;
391
392 /* now calculate first sector/dev */
393 chunk = r10bio->sector >> conf->chunk_shift;
394 sector = r10bio->sector & conf->chunk_mask;
395
396 chunk *= conf->near_copies;
397 stripe = chunk;
398 dev = sector_div(stripe, conf->raid_disks);
399
400 sector += stripe << conf->chunk_shift;
401
402 /* and calculate all the others */
403 for (n=0; n < conf->near_copies; n++) {
404 int d = dev;
405 sector_t s = sector;
406 r10bio->devs[slot].addr = sector;
407 r10bio->devs[slot].devnum = d;
408 slot++;
409
410 for (f = 1; f < conf->far_copies; f++) {
411 d += conf->near_copies;
412 if (d >= conf->raid_disks)
413 d -= conf->raid_disks;
414 s += conf->stride;
415 r10bio->devs[slot].devnum = d;
416 r10bio->devs[slot].addr = s;
417 slot++;
418 }
419 dev++;
420 if (dev >= conf->raid_disks) {
421 dev = 0;
422 sector += (conf->chunk_mask + 1);
423 }
424 }
425 BUG_ON(slot != conf->copies);
426}
427
428static sector_t raid10_find_virt(conf_t *conf, sector_t sector, int dev)
429{
430 sector_t offset, chunk, vchunk;
431
432 while (sector > conf->stride) {
433 sector -= conf->stride;
434 if (dev < conf->near_copies)
435 dev += conf->raid_disks - conf->near_copies;
436 else
437 dev -= conf->near_copies;
438 }
439
440 offset = sector & conf->chunk_mask;
441 chunk = sector >> conf->chunk_shift;
442 vchunk = chunk * conf->raid_disks + dev;
443 sector_div(vchunk, conf->near_copies);
444 return (vchunk << conf->chunk_shift) + offset;
445}
446
447/**
448 * raid10_mergeable_bvec -- tell bio layer if a two requests can be merged
449 * @q: request queue
450 * @bio: the buffer head that's been built up so far
451 * @biovec: the request that could be merged to it.
452 *
453 * Return amount of bytes we can accept at this offset
454 * If near_copies == raid_disk, there are no striping issues,
455 * but in that case, the function isn't called at all.
456 */
457static int raid10_mergeable_bvec(request_queue_t *q, struct bio *bio,
458 struct bio_vec *bio_vec)
459{
460 mddev_t *mddev = q->queuedata;
461 sector_t sector = bio->bi_sector + get_start_sect(bio->bi_bdev);
462 int max;
463 unsigned int chunk_sectors = mddev->chunk_size >> 9;
464 unsigned int bio_sectors = bio->bi_size >> 9;
465
466 max = (chunk_sectors - ((sector & (chunk_sectors - 1)) + bio_sectors)) << 9;
467 if (max < 0) max = 0; /* bio_add cannot handle a negative return */
468 if (max <= bio_vec->bv_len && bio_sectors == 0)
469 return bio_vec->bv_len;
470 else
471 return max;
472}
473
474/*
475 * This routine returns the disk from which the requested read should
476 * be done. There is a per-array 'next expected sequential IO' sector
477 * number - if this matches on the next IO then we use the last disk.
478 * There is also a per-disk 'last know head position' sector that is
479 * maintained from IRQ contexts, both the normal and the resync IO
480 * completion handlers update this position correctly. If there is no
481 * perfect sequential match then we pick the disk whose head is closest.
482 *
483 * If there are 2 mirrors in the same 2 devices, performance degrades
484 * because position is mirror, not device based.
485 *
486 * The rdev for the device selected will have nr_pending incremented.
487 */
488
489/*
490 * FIXME: possibly should rethink readbalancing and do it differently
491 * depending on near_copies / far_copies geometry.
492 */
493static int read_balance(conf_t *conf, r10bio_t *r10_bio)
494{
495 const unsigned long this_sector = r10_bio->sector;
496 int disk, slot, nslot;
497 const int sectors = r10_bio->sectors;
498 sector_t new_distance, current_distance;
Suzanne Woodd6065f72005-11-08 21:39:27 -0800499 mdk_rdev_t *rdev;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700500
501 raid10_find_phys(conf, r10_bio);
502 rcu_read_lock();
503 /*
504 * Check if we can balance. We can balance on the whole
505 * device if no resync is going on, or below the resync window.
506 * We take the first readable disk when above the resync window.
507 */
508 if (conf->mddev->recovery_cp < MaxSector
509 && (this_sector + sectors >= conf->next_resync)) {
510 /* make sure that disk is operational */
511 slot = 0;
512 disk = r10_bio->devs[slot].devnum;
513
Suzanne Woodd6065f72005-11-08 21:39:27 -0800514 while ((rdev = rcu_dereference(conf->mirrors[disk].rdev)) == NULL ||
NeilBrownb2d444d2005-11-08 21:39:31 -0800515 !test_bit(In_sync, &rdev->flags)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700516 slot++;
517 if (slot == conf->copies) {
518 slot = 0;
519 disk = -1;
520 break;
521 }
522 disk = r10_bio->devs[slot].devnum;
523 }
524 goto rb_out;
525 }
526
527
528 /* make sure the disk is operational */
529 slot = 0;
530 disk = r10_bio->devs[slot].devnum;
Suzanne Woodd6065f72005-11-08 21:39:27 -0800531 while ((rdev=rcu_dereference(conf->mirrors[disk].rdev)) == NULL ||
NeilBrownb2d444d2005-11-08 21:39:31 -0800532 !test_bit(In_sync, &rdev->flags)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700533 slot ++;
534 if (slot == conf->copies) {
535 disk = -1;
536 goto rb_out;
537 }
538 disk = r10_bio->devs[slot].devnum;
539 }
540
541
NeilBrown3ec67ac2005-09-09 16:23:40 -0700542 current_distance = abs(r10_bio->devs[slot].addr -
543 conf->mirrors[disk].head_position);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700544
545 /* Find the disk whose head is closest */
546
547 for (nslot = slot; nslot < conf->copies; nslot++) {
548 int ndisk = r10_bio->devs[nslot].devnum;
549
550
Suzanne Woodd6065f72005-11-08 21:39:27 -0800551 if ((rdev=rcu_dereference(conf->mirrors[ndisk].rdev)) == NULL ||
NeilBrownb2d444d2005-11-08 21:39:31 -0800552 !test_bit(In_sync, &rdev->flags))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700553 continue;
554
Suzanne Woodd6065f72005-11-08 21:39:27 -0800555 if (!atomic_read(&rdev->nr_pending)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700556 disk = ndisk;
557 slot = nslot;
558 break;
559 }
560 new_distance = abs(r10_bio->devs[nslot].addr -
561 conf->mirrors[ndisk].head_position);
562 if (new_distance < current_distance) {
563 current_distance = new_distance;
564 disk = ndisk;
565 slot = nslot;
566 }
567 }
568
569rb_out:
570 r10_bio->read_slot = slot;
571/* conf->next_seq_sect = this_sector + sectors;*/
572
Suzanne Woodd6065f72005-11-08 21:39:27 -0800573 if (disk >= 0 && (rdev=rcu_dereference(conf->mirrors[disk].rdev))!= NULL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700574 atomic_inc(&conf->mirrors[disk].rdev->nr_pending);
575 rcu_read_unlock();
576
577 return disk;
578}
579
580static void unplug_slaves(mddev_t *mddev)
581{
582 conf_t *conf = mddev_to_conf(mddev);
583 int i;
584
585 rcu_read_lock();
586 for (i=0; i<mddev->raid_disks; i++) {
Suzanne Woodd6065f72005-11-08 21:39:27 -0800587 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
NeilBrownb2d444d2005-11-08 21:39:31 -0800588 if (rdev && !test_bit(Faulty, &rdev->flags) && atomic_read(&rdev->nr_pending)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700589 request_queue_t *r_queue = bdev_get_queue(rdev->bdev);
590
591 atomic_inc(&rdev->nr_pending);
592 rcu_read_unlock();
593
594 if (r_queue->unplug_fn)
595 r_queue->unplug_fn(r_queue);
596
597 rdev_dec_pending(rdev, mddev);
598 rcu_read_lock();
599 }
600 }
601 rcu_read_unlock();
602}
603
604static void raid10_unplug(request_queue_t *q)
605{
606 unplug_slaves(q->queuedata);
607}
608
609static int raid10_issue_flush(request_queue_t *q, struct gendisk *disk,
610 sector_t *error_sector)
611{
612 mddev_t *mddev = q->queuedata;
613 conf_t *conf = mddev_to_conf(mddev);
614 int i, ret = 0;
615
616 rcu_read_lock();
617 for (i=0; i<mddev->raid_disks && ret == 0; i++) {
Suzanne Woodd6065f72005-11-08 21:39:27 -0800618 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
NeilBrownb2d444d2005-11-08 21:39:31 -0800619 if (rdev && !test_bit(Faulty, &rdev->flags)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700620 struct block_device *bdev = rdev->bdev;
621 request_queue_t *r_queue = bdev_get_queue(bdev);
622
623 if (!r_queue->issue_flush_fn)
624 ret = -EOPNOTSUPP;
625 else {
626 atomic_inc(&rdev->nr_pending);
627 rcu_read_unlock();
628 ret = r_queue->issue_flush_fn(r_queue, bdev->bd_disk,
629 error_sector);
630 rdev_dec_pending(rdev, mddev);
631 rcu_read_lock();
632 }
633 }
634 }
635 rcu_read_unlock();
636 return ret;
637}
638
639/*
640 * Throttle resync depth, so that we can both get proper overlapping of
641 * requests, but are still able to handle normal requests quickly.
642 */
643#define RESYNC_DEPTH 32
644
645static void device_barrier(conf_t *conf, sector_t sect)
646{
647 spin_lock_irq(&conf->resync_lock);
648 wait_event_lock_irq(conf->wait_idle, !waitqueue_active(&conf->wait_resume),
649 conf->resync_lock, unplug_slaves(conf->mddev));
650
651 if (!conf->barrier++) {
652 wait_event_lock_irq(conf->wait_idle, !conf->nr_pending,
653 conf->resync_lock, unplug_slaves(conf->mddev));
654 if (conf->nr_pending)
655 BUG();
656 }
657 wait_event_lock_irq(conf->wait_resume, conf->barrier < RESYNC_DEPTH,
658 conf->resync_lock, unplug_slaves(conf->mddev));
659 conf->next_resync = sect;
660 spin_unlock_irq(&conf->resync_lock);
661}
662
663static int make_request(request_queue_t *q, struct bio * bio)
664{
665 mddev_t *mddev = q->queuedata;
666 conf_t *conf = mddev_to_conf(mddev);
667 mirror_info_t *mirror;
668 r10bio_t *r10_bio;
669 struct bio *read_bio;
670 int i;
671 int chunk_sects = conf->chunk_mask + 1;
Jens Axboea3623572005-11-01 09:26:16 +0100672 const int rw = bio_data_dir(bio);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700673
NeilBrowne5dcdd82005-09-09 16:23:41 -0700674 if (unlikely(bio_barrier(bio))) {
675 bio_endio(bio, bio->bi_size, -EOPNOTSUPP);
676 return 0;
677 }
678
Linus Torvalds1da177e2005-04-16 15:20:36 -0700679 /* If this request crosses a chunk boundary, we need to
680 * split it. This will only happen for 1 PAGE (or less) requests.
681 */
682 if (unlikely( (bio->bi_sector & conf->chunk_mask) + (bio->bi_size >> 9)
683 > chunk_sects &&
684 conf->near_copies < conf->raid_disks)) {
685 struct bio_pair *bp;
686 /* Sanity check -- queue functions should prevent this happening */
687 if (bio->bi_vcnt != 1 ||
688 bio->bi_idx != 0)
689 goto bad_map;
690 /* This is a one page bio that upper layers
691 * refuse to split for us, so we need to split it.
692 */
693 bp = bio_split(bio, bio_split_pool,
694 chunk_sects - (bio->bi_sector & (chunk_sects - 1)) );
695 if (make_request(q, &bp->bio1))
696 generic_make_request(&bp->bio1);
697 if (make_request(q, &bp->bio2))
698 generic_make_request(&bp->bio2);
699
700 bio_pair_release(bp);
701 return 0;
702 bad_map:
703 printk("raid10_make_request bug: can't convert block across chunks"
704 " or bigger than %dk %llu %d\n", chunk_sects/2,
705 (unsigned long long)bio->bi_sector, bio->bi_size >> 10);
706
707 bio_io_error(bio, bio->bi_size);
708 return 0;
709 }
710
NeilBrown3d310eb2005-06-21 17:17:26 -0700711 md_write_start(mddev, bio);
NeilBrown06d91a52005-06-21 17:17:12 -0700712
Linus Torvalds1da177e2005-04-16 15:20:36 -0700713 /*
714 * Register the new request and wait if the reconstruction
715 * thread has put up a bar for new requests.
716 * Continue immediately if no resync is active currently.
717 */
718 spin_lock_irq(&conf->resync_lock);
719 wait_event_lock_irq(conf->wait_resume, !conf->barrier, conf->resync_lock, );
720 conf->nr_pending++;
721 spin_unlock_irq(&conf->resync_lock);
722
Jens Axboea3623572005-11-01 09:26:16 +0100723 disk_stat_inc(mddev->gendisk, ios[rw]);
724 disk_stat_add(mddev->gendisk, sectors[rw], bio_sectors(bio));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700725
726 r10_bio = mempool_alloc(conf->r10bio_pool, GFP_NOIO);
727
728 r10_bio->master_bio = bio;
729 r10_bio->sectors = bio->bi_size >> 9;
730
731 r10_bio->mddev = mddev;
732 r10_bio->sector = bio->bi_sector;
733
Jens Axboea3623572005-11-01 09:26:16 +0100734 if (rw == READ) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700735 /*
736 * read balancing logic:
737 */
738 int disk = read_balance(conf, r10_bio);
739 int slot = r10_bio->read_slot;
740 if (disk < 0) {
741 raid_end_bio_io(r10_bio);
742 return 0;
743 }
744 mirror = conf->mirrors + disk;
745
746 read_bio = bio_clone(bio, GFP_NOIO);
747
748 r10_bio->devs[slot].bio = read_bio;
749
750 read_bio->bi_sector = r10_bio->devs[slot].addr +
751 mirror->rdev->data_offset;
752 read_bio->bi_bdev = mirror->rdev->bdev;
753 read_bio->bi_end_io = raid10_end_read_request;
754 read_bio->bi_rw = READ;
755 read_bio->bi_private = r10_bio;
756
757 generic_make_request(read_bio);
758 return 0;
759 }
760
761 /*
762 * WRITE:
763 */
764 /* first select target devices under spinlock and
765 * inc refcount on their rdev. Record them by setting
766 * bios[x] to bio
767 */
768 raid10_find_phys(conf, r10_bio);
769 rcu_read_lock();
770 for (i = 0; i < conf->copies; i++) {
771 int d = r10_bio->devs[i].devnum;
Suzanne Woodd6065f72005-11-08 21:39:27 -0800772 mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[d].rdev);
773 if (rdev &&
NeilBrownb2d444d2005-11-08 21:39:31 -0800774 !test_bit(Faulty, &rdev->flags)) {
Suzanne Woodd6065f72005-11-08 21:39:27 -0800775 atomic_inc(&rdev->nr_pending);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700776 r10_bio->devs[i].bio = bio;
777 } else
778 r10_bio->devs[i].bio = NULL;
779 }
780 rcu_read_unlock();
781
782 atomic_set(&r10_bio->remaining, 1);
NeilBrown06d91a52005-06-21 17:17:12 -0700783
Linus Torvalds1da177e2005-04-16 15:20:36 -0700784 for (i = 0; i < conf->copies; i++) {
785 struct bio *mbio;
786 int d = r10_bio->devs[i].devnum;
787 if (!r10_bio->devs[i].bio)
788 continue;
789
790 mbio = bio_clone(bio, GFP_NOIO);
791 r10_bio->devs[i].bio = mbio;
792
793 mbio->bi_sector = r10_bio->devs[i].addr+
794 conf->mirrors[d].rdev->data_offset;
795 mbio->bi_bdev = conf->mirrors[d].rdev->bdev;
796 mbio->bi_end_io = raid10_end_write_request;
797 mbio->bi_rw = WRITE;
798 mbio->bi_private = r10_bio;
799
800 atomic_inc(&r10_bio->remaining);
801 generic_make_request(mbio);
802 }
803
804 if (atomic_dec_and_test(&r10_bio->remaining)) {
805 md_write_end(mddev);
806 raid_end_bio_io(r10_bio);
807 }
808
809 return 0;
810}
811
812static void status(struct seq_file *seq, mddev_t *mddev)
813{
814 conf_t *conf = mddev_to_conf(mddev);
815 int i;
816
817 if (conf->near_copies < conf->raid_disks)
818 seq_printf(seq, " %dK chunks", mddev->chunk_size/1024);
819 if (conf->near_copies > 1)
820 seq_printf(seq, " %d near-copies", conf->near_copies);
821 if (conf->far_copies > 1)
822 seq_printf(seq, " %d far-copies", conf->far_copies);
823
824 seq_printf(seq, " [%d/%d] [", conf->raid_disks,
825 conf->working_disks);
826 for (i = 0; i < conf->raid_disks; i++)
827 seq_printf(seq, "%s",
828 conf->mirrors[i].rdev &&
NeilBrownb2d444d2005-11-08 21:39:31 -0800829 test_bit(In_sync, &conf->mirrors[i].rdev->flags) ? "U" : "_");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700830 seq_printf(seq, "]");
831}
832
833static void error(mddev_t *mddev, mdk_rdev_t *rdev)
834{
835 char b[BDEVNAME_SIZE];
836 conf_t *conf = mddev_to_conf(mddev);
837
838 /*
839 * If it is not operational, then we have already marked it as dead
840 * else if it is the last working disks, ignore the error, let the
841 * next level up know.
842 * else mark the drive as failed
843 */
NeilBrownb2d444d2005-11-08 21:39:31 -0800844 if (test_bit(In_sync, &rdev->flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700845 && conf->working_disks == 1)
846 /*
847 * Don't fail the drive, just return an IO error.
848 * The test should really be more sophisticated than
849 * "working_disks == 1", but it isn't critical, and
850 * can wait until we do more sophisticated "is the drive
851 * really dead" tests...
852 */
853 return;
NeilBrownb2d444d2005-11-08 21:39:31 -0800854 if (test_bit(In_sync, &rdev->flags)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700855 mddev->degraded++;
856 conf->working_disks--;
857 /*
858 * if recovery is running, make sure it aborts.
859 */
860 set_bit(MD_RECOVERY_ERR, &mddev->recovery);
861 }
NeilBrownb2d444d2005-11-08 21:39:31 -0800862 clear_bit(In_sync, &rdev->flags);
863 set_bit(Faulty, &rdev->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700864 mddev->sb_dirty = 1;
865 printk(KERN_ALERT "raid10: Disk failure on %s, disabling device. \n"
866 " Operation continuing on %d devices\n",
867 bdevname(rdev->bdev,b), conf->working_disks);
868}
869
870static void print_conf(conf_t *conf)
871{
872 int i;
873 mirror_info_t *tmp;
874
875 printk("RAID10 conf printout:\n");
876 if (!conf) {
877 printk("(!conf)\n");
878 return;
879 }
880 printk(" --- wd:%d rd:%d\n", conf->working_disks,
881 conf->raid_disks);
882
883 for (i = 0; i < conf->raid_disks; i++) {
884 char b[BDEVNAME_SIZE];
885 tmp = conf->mirrors + i;
886 if (tmp->rdev)
887 printk(" disk %d, wo:%d, o:%d, dev:%s\n",
NeilBrownb2d444d2005-11-08 21:39:31 -0800888 i, !test_bit(In_sync, &tmp->rdev->flags),
889 !test_bit(Faulty, &tmp->rdev->flags),
Linus Torvalds1da177e2005-04-16 15:20:36 -0700890 bdevname(tmp->rdev->bdev,b));
891 }
892}
893
894static void close_sync(conf_t *conf)
895{
896 spin_lock_irq(&conf->resync_lock);
897 wait_event_lock_irq(conf->wait_resume, !conf->barrier,
898 conf->resync_lock, unplug_slaves(conf->mddev));
899 spin_unlock_irq(&conf->resync_lock);
900
901 if (conf->barrier) BUG();
902 if (waitqueue_active(&conf->wait_idle)) BUG();
903
904 mempool_destroy(conf->r10buf_pool);
905 conf->r10buf_pool = NULL;
906}
907
NeilBrown6d508242005-09-09 16:24:03 -0700908/* check if there are enough drives for
909 * every block to appear on atleast one
910 */
911static int enough(conf_t *conf)
912{
913 int first = 0;
914
915 do {
916 int n = conf->copies;
917 int cnt = 0;
918 while (n--) {
919 if (conf->mirrors[first].rdev)
920 cnt++;
921 first = (first+1) % conf->raid_disks;
922 }
923 if (cnt == 0)
924 return 0;
925 } while (first != 0);
926 return 1;
927}
928
Linus Torvalds1da177e2005-04-16 15:20:36 -0700929static int raid10_spare_active(mddev_t *mddev)
930{
931 int i;
932 conf_t *conf = mddev->private;
933 mirror_info_t *tmp;
934
935 /*
936 * Find all non-in_sync disks within the RAID10 configuration
937 * and mark them in_sync
938 */
939 for (i = 0; i < conf->raid_disks; i++) {
940 tmp = conf->mirrors + i;
941 if (tmp->rdev
NeilBrownb2d444d2005-11-08 21:39:31 -0800942 && !test_bit(Faulty, &tmp->rdev->flags)
943 && !test_bit(In_sync, &tmp->rdev->flags)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700944 conf->working_disks++;
945 mddev->degraded--;
NeilBrownb2d444d2005-11-08 21:39:31 -0800946 set_bit(In_sync, &tmp->rdev->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700947 }
948 }
949
950 print_conf(conf);
951 return 0;
952}
953
954
955static int raid10_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
956{
957 conf_t *conf = mddev->private;
958 int found = 0;
959 int mirror;
960 mirror_info_t *p;
961
962 if (mddev->recovery_cp < MaxSector)
963 /* only hot-add to in-sync arrays, as recovery is
964 * very different from resync
965 */
966 return 0;
NeilBrown6d508242005-09-09 16:24:03 -0700967 if (!enough(conf))
968 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700969
970 for (mirror=0; mirror < mddev->raid_disks; mirror++)
971 if ( !(p=conf->mirrors+mirror)->rdev) {
972
973 blk_queue_stack_limits(mddev->queue,
974 rdev->bdev->bd_disk->queue);
975 /* as we don't honour merge_bvec_fn, we must never risk
976 * violating it, so limit ->max_sector to one PAGE, as
977 * a one page request is never in violation.
978 */
979 if (rdev->bdev->bd_disk->queue->merge_bvec_fn &&
980 mddev->queue->max_sectors > (PAGE_SIZE>>9))
981 mddev->queue->max_sectors = (PAGE_SIZE>>9);
982
983 p->head_position = 0;
984 rdev->raid_disk = mirror;
985 found = 1;
Suzanne Woodd6065f72005-11-08 21:39:27 -0800986 rcu_assign_pointer(p->rdev, rdev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700987 break;
988 }
989
990 print_conf(conf);
991 return found;
992}
993
994static int raid10_remove_disk(mddev_t *mddev, int number)
995{
996 conf_t *conf = mddev->private;
997 int err = 0;
998 mdk_rdev_t *rdev;
999 mirror_info_t *p = conf->mirrors+ number;
1000
1001 print_conf(conf);
1002 rdev = p->rdev;
1003 if (rdev) {
NeilBrownb2d444d2005-11-08 21:39:31 -08001004 if (test_bit(In_sync, &rdev->flags) ||
Linus Torvalds1da177e2005-04-16 15:20:36 -07001005 atomic_read(&rdev->nr_pending)) {
1006 err = -EBUSY;
1007 goto abort;
1008 }
1009 p->rdev = NULL;
Paul E. McKenneyfbd568a3e2005-05-01 08:59:04 -07001010 synchronize_rcu();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001011 if (atomic_read(&rdev->nr_pending)) {
1012 /* lost the race, try later */
1013 err = -EBUSY;
1014 p->rdev = rdev;
1015 }
1016 }
1017abort:
1018
1019 print_conf(conf);
1020 return err;
1021}
1022
1023
1024static int end_sync_read(struct bio *bio, unsigned int bytes_done, int error)
1025{
1026 int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
1027 r10bio_t * r10_bio = (r10bio_t *)(bio->bi_private);
1028 conf_t *conf = mddev_to_conf(r10_bio->mddev);
1029 int i,d;
1030
1031 if (bio->bi_size)
1032 return 1;
1033
1034 for (i=0; i<conf->copies; i++)
1035 if (r10_bio->devs[i].bio == bio)
1036 break;
1037 if (i == conf->copies)
1038 BUG();
1039 update_head_pos(i, r10_bio);
1040 d = r10_bio->devs[i].devnum;
1041 if (!uptodate)
1042 md_error(r10_bio->mddev,
1043 conf->mirrors[d].rdev);
1044
1045 /* for reconstruct, we always reschedule after a read.
1046 * for resync, only after all reads
1047 */
1048 if (test_bit(R10BIO_IsRecover, &r10_bio->state) ||
1049 atomic_dec_and_test(&r10_bio->remaining)) {
1050 /* we have read all the blocks,
1051 * do the comparison in process context in raid10d
1052 */
1053 reschedule_retry(r10_bio);
1054 }
1055 rdev_dec_pending(conf->mirrors[d].rdev, conf->mddev);
1056 return 0;
1057}
1058
1059static int end_sync_write(struct bio *bio, unsigned int bytes_done, int error)
1060{
1061 int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
1062 r10bio_t * r10_bio = (r10bio_t *)(bio->bi_private);
1063 mddev_t *mddev = r10_bio->mddev;
1064 conf_t *conf = mddev_to_conf(mddev);
1065 int i,d;
1066
1067 if (bio->bi_size)
1068 return 1;
1069
1070 for (i = 0; i < conf->copies; i++)
1071 if (r10_bio->devs[i].bio == bio)
1072 break;
1073 d = r10_bio->devs[i].devnum;
1074
1075 if (!uptodate)
1076 md_error(mddev, conf->mirrors[d].rdev);
1077 update_head_pos(i, r10_bio);
1078
1079 while (atomic_dec_and_test(&r10_bio->remaining)) {
1080 if (r10_bio->master_bio == NULL) {
1081 /* the primary of several recovery bios */
1082 md_done_sync(mddev, r10_bio->sectors, 1);
1083 put_buf(r10_bio);
1084 break;
1085 } else {
1086 r10bio_t *r10_bio2 = (r10bio_t *)r10_bio->master_bio;
1087 put_buf(r10_bio);
1088 r10_bio = r10_bio2;
1089 }
1090 }
1091 rdev_dec_pending(conf->mirrors[d].rdev, mddev);
1092 return 0;
1093}
1094
1095/*
1096 * Note: sync and recover and handled very differently for raid10
1097 * This code is for resync.
1098 * For resync, we read through virtual addresses and read all blocks.
1099 * If there is any error, we schedule a write. The lowest numbered
1100 * drive is authoritative.
1101 * However requests come for physical address, so we need to map.
1102 * For every physical address there are raid_disks/copies virtual addresses,
1103 * which is always are least one, but is not necessarly an integer.
1104 * This means that a physical address can span multiple chunks, so we may
1105 * have to submit multiple io requests for a single sync request.
1106 */
1107/*
1108 * We check if all blocks are in-sync and only write to blocks that
1109 * aren't in sync
1110 */
1111static void sync_request_write(mddev_t *mddev, r10bio_t *r10_bio)
1112{
1113 conf_t *conf = mddev_to_conf(mddev);
1114 int i, first;
1115 struct bio *tbio, *fbio;
1116
1117 atomic_set(&r10_bio->remaining, 1);
1118
1119 /* find the first device with a block */
1120 for (i=0; i<conf->copies; i++)
1121 if (test_bit(BIO_UPTODATE, &r10_bio->devs[i].bio->bi_flags))
1122 break;
1123
1124 if (i == conf->copies)
1125 goto done;
1126
1127 first = i;
1128 fbio = r10_bio->devs[i].bio;
1129
1130 /* now find blocks with errors */
1131 for (i=first+1 ; i < conf->copies ; i++) {
1132 int vcnt, j, d;
1133
1134 if (!test_bit(BIO_UPTODATE, &r10_bio->devs[i].bio->bi_flags))
1135 continue;
1136 /* We know that the bi_io_vec layout is the same for
1137 * both 'first' and 'i', so we just compare them.
1138 * All vec entries are PAGE_SIZE;
1139 */
1140 tbio = r10_bio->devs[i].bio;
1141 vcnt = r10_bio->sectors >> (PAGE_SHIFT-9);
1142 for (j = 0; j < vcnt; j++)
1143 if (memcmp(page_address(fbio->bi_io_vec[j].bv_page),
1144 page_address(tbio->bi_io_vec[j].bv_page),
1145 PAGE_SIZE))
1146 break;
1147 if (j == vcnt)
1148 continue;
1149 /* Ok, we need to write this bio
1150 * First we need to fixup bv_offset, bv_len and
1151 * bi_vecs, as the read request might have corrupted these
1152 */
1153 tbio->bi_vcnt = vcnt;
1154 tbio->bi_size = r10_bio->sectors << 9;
1155 tbio->bi_idx = 0;
1156 tbio->bi_phys_segments = 0;
1157 tbio->bi_hw_segments = 0;
1158 tbio->bi_hw_front_size = 0;
1159 tbio->bi_hw_back_size = 0;
1160 tbio->bi_flags &= ~(BIO_POOL_MASK - 1);
1161 tbio->bi_flags |= 1 << BIO_UPTODATE;
1162 tbio->bi_next = NULL;
1163 tbio->bi_rw = WRITE;
1164 tbio->bi_private = r10_bio;
1165 tbio->bi_sector = r10_bio->devs[i].addr;
1166
1167 for (j=0; j < vcnt ; j++) {
1168 tbio->bi_io_vec[j].bv_offset = 0;
1169 tbio->bi_io_vec[j].bv_len = PAGE_SIZE;
1170
1171 memcpy(page_address(tbio->bi_io_vec[j].bv_page),
1172 page_address(fbio->bi_io_vec[j].bv_page),
1173 PAGE_SIZE);
1174 }
1175 tbio->bi_end_io = end_sync_write;
1176
1177 d = r10_bio->devs[i].devnum;
1178 atomic_inc(&conf->mirrors[d].rdev->nr_pending);
1179 atomic_inc(&r10_bio->remaining);
1180 md_sync_acct(conf->mirrors[d].rdev->bdev, tbio->bi_size >> 9);
1181
1182 tbio->bi_sector += conf->mirrors[d].rdev->data_offset;
1183 tbio->bi_bdev = conf->mirrors[d].rdev->bdev;
1184 generic_make_request(tbio);
1185 }
1186
1187done:
1188 if (atomic_dec_and_test(&r10_bio->remaining)) {
1189 md_done_sync(mddev, r10_bio->sectors, 1);
1190 put_buf(r10_bio);
1191 }
1192}
1193
1194/*
1195 * Now for the recovery code.
1196 * Recovery happens across physical sectors.
1197 * We recover all non-is_sync drives by finding the virtual address of
1198 * each, and then choose a working drive that also has that virt address.
1199 * There is a separate r10_bio for each non-in_sync drive.
1200 * Only the first two slots are in use. The first for reading,
1201 * The second for writing.
1202 *
1203 */
1204
1205static void recovery_request_write(mddev_t *mddev, r10bio_t *r10_bio)
1206{
1207 conf_t *conf = mddev_to_conf(mddev);
1208 int i, d;
1209 struct bio *bio, *wbio;
1210
1211
1212 /* move the pages across to the second bio
1213 * and submit the write request
1214 */
1215 bio = r10_bio->devs[0].bio;
1216 wbio = r10_bio->devs[1].bio;
1217 for (i=0; i < wbio->bi_vcnt; i++) {
1218 struct page *p = bio->bi_io_vec[i].bv_page;
1219 bio->bi_io_vec[i].bv_page = wbio->bi_io_vec[i].bv_page;
1220 wbio->bi_io_vec[i].bv_page = p;
1221 }
1222 d = r10_bio->devs[1].devnum;
1223
1224 atomic_inc(&conf->mirrors[d].rdev->nr_pending);
1225 md_sync_acct(conf->mirrors[d].rdev->bdev, wbio->bi_size >> 9);
1226 generic_make_request(wbio);
1227}
1228
1229
1230/*
1231 * This is a kernel thread which:
1232 *
1233 * 1. Retries failed read operations on working mirrors.
1234 * 2. Updates the raid superblock when problems encounter.
1235 * 3. Performs writes following reads for array syncronising.
1236 */
1237
1238static void raid10d(mddev_t *mddev)
1239{
1240 r10bio_t *r10_bio;
1241 struct bio *bio;
1242 unsigned long flags;
1243 conf_t *conf = mddev_to_conf(mddev);
1244 struct list_head *head = &conf->retry_list;
1245 int unplug=0;
1246 mdk_rdev_t *rdev;
1247
1248 md_check_recovery(mddev);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001249
1250 for (;;) {
1251 char b[BDEVNAME_SIZE];
1252 spin_lock_irqsave(&conf->device_lock, flags);
1253 if (list_empty(head))
1254 break;
1255 r10_bio = list_entry(head->prev, r10bio_t, retry_list);
1256 list_del(head->prev);
1257 spin_unlock_irqrestore(&conf->device_lock, flags);
1258
1259 mddev = r10_bio->mddev;
1260 conf = mddev_to_conf(mddev);
1261 if (test_bit(R10BIO_IsSync, &r10_bio->state)) {
1262 sync_request_write(mddev, r10_bio);
1263 unplug = 1;
1264 } else if (test_bit(R10BIO_IsRecover, &r10_bio->state)) {
1265 recovery_request_write(mddev, r10_bio);
1266 unplug = 1;
1267 } else {
1268 int mirror;
1269 bio = r10_bio->devs[r10_bio->read_slot].bio;
1270 r10_bio->devs[r10_bio->read_slot].bio = NULL;
1271 bio_put(bio);
1272 mirror = read_balance(conf, r10_bio);
1273 if (mirror == -1) {
1274 printk(KERN_ALERT "raid10: %s: unrecoverable I/O"
1275 " read error for block %llu\n",
1276 bdevname(bio->bi_bdev,b),
1277 (unsigned long long)r10_bio->sector);
1278 raid_end_bio_io(r10_bio);
1279 } else {
1280 rdev = conf->mirrors[mirror].rdev;
1281 if (printk_ratelimit())
1282 printk(KERN_ERR "raid10: %s: redirecting sector %llu to"
1283 " another mirror\n",
1284 bdevname(rdev->bdev,b),
1285 (unsigned long long)r10_bio->sector);
1286 bio = bio_clone(r10_bio->master_bio, GFP_NOIO);
1287 r10_bio->devs[r10_bio->read_slot].bio = bio;
1288 bio->bi_sector = r10_bio->devs[r10_bio->read_slot].addr
1289 + rdev->data_offset;
1290 bio->bi_bdev = rdev->bdev;
1291 bio->bi_rw = READ;
1292 bio->bi_private = r10_bio;
1293 bio->bi_end_io = raid10_end_read_request;
1294 unplug = 1;
1295 generic_make_request(bio);
1296 }
1297 }
1298 }
1299 spin_unlock_irqrestore(&conf->device_lock, flags);
1300 if (unplug)
1301 unplug_slaves(mddev);
1302}
1303
1304
1305static int init_resync(conf_t *conf)
1306{
1307 int buffs;
1308
1309 buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE;
1310 if (conf->r10buf_pool)
1311 BUG();
1312 conf->r10buf_pool = mempool_create(buffs, r10buf_pool_alloc, r10buf_pool_free, conf);
1313 if (!conf->r10buf_pool)
1314 return -ENOMEM;
1315 conf->next_resync = 0;
1316 return 0;
1317}
1318
1319/*
1320 * perform a "sync" on one "block"
1321 *
1322 * We need to make sure that no normal I/O request - particularly write
1323 * requests - conflict with active sync requests.
1324 *
1325 * This is achieved by tracking pending requests and a 'barrier' concept
1326 * that can be installed to exclude normal IO requests.
1327 *
1328 * Resync and recovery are handled very differently.
1329 * We differentiate by looking at MD_RECOVERY_SYNC in mddev->recovery.
1330 *
1331 * For resync, we iterate over virtual addresses, read all copies,
1332 * and update if there are differences. If only one copy is live,
1333 * skip it.
1334 * For recovery, we iterate over physical addresses, read a good
1335 * value for each non-in_sync drive, and over-write.
1336 *
1337 * So, for recovery we may have several outstanding complex requests for a
1338 * given address, one for each out-of-sync device. We model this by allocating
1339 * a number of r10_bio structures, one for each out-of-sync device.
1340 * As we setup these structures, we collect all bio's together into a list
1341 * which we then process collectively to add pages, and then process again
1342 * to pass to generic_make_request.
1343 *
1344 * The r10_bio structures are linked using a borrowed master_bio pointer.
1345 * This link is counted in ->remaining. When the r10_bio that points to NULL
1346 * has its remaining count decremented to 0, the whole complex operation
1347 * is complete.
1348 *
1349 */
1350
NeilBrown57afd892005-06-21 17:17:13 -07001351static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001352{
1353 conf_t *conf = mddev_to_conf(mddev);
1354 r10bio_t *r10_bio;
1355 struct bio *biolist = NULL, *bio;
1356 sector_t max_sector, nr_sectors;
1357 int disk;
1358 int i;
1359
1360 sector_t sectors_skipped = 0;
1361 int chunks_skipped = 0;
1362
1363 if (!conf->r10buf_pool)
1364 if (init_resync(conf))
NeilBrown57afd892005-06-21 17:17:13 -07001365 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001366
1367 skipped:
1368 max_sector = mddev->size << 1;
1369 if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery))
1370 max_sector = mddev->resync_max_sectors;
1371 if (sector_nr >= max_sector) {
1372 close_sync(conf);
NeilBrown57afd892005-06-21 17:17:13 -07001373 *skipped = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001374 return sectors_skipped;
1375 }
1376 if (chunks_skipped >= conf->raid_disks) {
1377 /* if there has been nothing to do on any drive,
1378 * then there is nothing to do at all..
1379 */
NeilBrown57afd892005-06-21 17:17:13 -07001380 *skipped = 1;
1381 return (max_sector - sector_nr) + sectors_skipped;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001382 }
1383
1384 /* make sure whole request will fit in a chunk - if chunks
1385 * are meaningful
1386 */
1387 if (conf->near_copies < conf->raid_disks &&
1388 max_sector > (sector_nr | conf->chunk_mask))
1389 max_sector = (sector_nr | conf->chunk_mask) + 1;
1390 /*
1391 * If there is non-resync activity waiting for us then
1392 * put in a delay to throttle resync.
1393 */
1394 if (!go_faster && waitqueue_active(&conf->wait_resume))
1395 msleep_interruptible(1000);
1396 device_barrier(conf, sector_nr + RESYNC_SECTORS);
1397
1398 /* Again, very different code for resync and recovery.
1399 * Both must result in an r10bio with a list of bios that
1400 * have bi_end_io, bi_sector, bi_bdev set,
1401 * and bi_private set to the r10bio.
1402 * For recovery, we may actually create several r10bios
1403 * with 2 bios in each, that correspond to the bios in the main one.
1404 * In this case, the subordinate r10bios link back through a
1405 * borrowed master_bio pointer, and the counter in the master
1406 * includes a ref from each subordinate.
1407 */
1408 /* First, we decide what to do and set ->bi_end_io
1409 * To end_sync_read if we want to read, and
1410 * end_sync_write if we will want to write.
1411 */
1412
1413 if (!test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
1414 /* recovery... the complicated one */
1415 int i, j, k;
1416 r10_bio = NULL;
1417
1418 for (i=0 ; i<conf->raid_disks; i++)
1419 if (conf->mirrors[i].rdev &&
NeilBrownb2d444d2005-11-08 21:39:31 -08001420 !test_bit(In_sync, &conf->mirrors[i].rdev->flags)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001421 /* want to reconstruct this device */
1422 r10bio_t *rb2 = r10_bio;
1423
1424 r10_bio = mempool_alloc(conf->r10buf_pool, GFP_NOIO);
1425 spin_lock_irq(&conf->resync_lock);
1426 conf->nr_pending++;
1427 if (rb2) conf->barrier++;
1428 spin_unlock_irq(&conf->resync_lock);
1429 atomic_set(&r10_bio->remaining, 0);
1430
1431 r10_bio->master_bio = (struct bio*)rb2;
1432 if (rb2)
1433 atomic_inc(&rb2->remaining);
1434 r10_bio->mddev = mddev;
1435 set_bit(R10BIO_IsRecover, &r10_bio->state);
1436 r10_bio->sector = raid10_find_virt(conf, sector_nr, i);
1437 raid10_find_phys(conf, r10_bio);
1438 for (j=0; j<conf->copies;j++) {
1439 int d = r10_bio->devs[j].devnum;
1440 if (conf->mirrors[d].rdev &&
NeilBrownb2d444d2005-11-08 21:39:31 -08001441 test_bit(In_sync, &conf->mirrors[d].rdev->flags)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001442 /* This is where we read from */
1443 bio = r10_bio->devs[0].bio;
1444 bio->bi_next = biolist;
1445 biolist = bio;
1446 bio->bi_private = r10_bio;
1447 bio->bi_end_io = end_sync_read;
1448 bio->bi_rw = 0;
1449 bio->bi_sector = r10_bio->devs[j].addr +
1450 conf->mirrors[d].rdev->data_offset;
1451 bio->bi_bdev = conf->mirrors[d].rdev->bdev;
1452 atomic_inc(&conf->mirrors[d].rdev->nr_pending);
1453 atomic_inc(&r10_bio->remaining);
1454 /* and we write to 'i' */
1455
1456 for (k=0; k<conf->copies; k++)
1457 if (r10_bio->devs[k].devnum == i)
1458 break;
1459 bio = r10_bio->devs[1].bio;
1460 bio->bi_next = biolist;
1461 biolist = bio;
1462 bio->bi_private = r10_bio;
1463 bio->bi_end_io = end_sync_write;
1464 bio->bi_rw = 1;
1465 bio->bi_sector = r10_bio->devs[k].addr +
1466 conf->mirrors[i].rdev->data_offset;
1467 bio->bi_bdev = conf->mirrors[i].rdev->bdev;
1468
1469 r10_bio->devs[0].devnum = d;
1470 r10_bio->devs[1].devnum = i;
1471
1472 break;
1473 }
1474 }
1475 if (j == conf->copies) {
NeilBrown87fc7672005-09-09 16:24:04 -07001476 /* Cannot recover, so abort the recovery */
1477 put_buf(r10_bio);
1478 r10_bio = rb2;
1479 if (!test_and_set_bit(MD_RECOVERY_ERR, &mddev->recovery))
1480 printk(KERN_INFO "raid10: %s: insufficient working devices for recovery.\n",
1481 mdname(mddev));
1482 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001483 }
1484 }
1485 if (biolist == NULL) {
1486 while (r10_bio) {
1487 r10bio_t *rb2 = r10_bio;
1488 r10_bio = (r10bio_t*) rb2->master_bio;
1489 rb2->master_bio = NULL;
1490 put_buf(rb2);
1491 }
1492 goto giveup;
1493 }
1494 } else {
1495 /* resync. Schedule a read for every block at this virt offset */
1496 int count = 0;
1497 r10_bio = mempool_alloc(conf->r10buf_pool, GFP_NOIO);
1498
1499 spin_lock_irq(&conf->resync_lock);
1500 conf->nr_pending++;
1501 spin_unlock_irq(&conf->resync_lock);
1502
1503 r10_bio->mddev = mddev;
1504 atomic_set(&r10_bio->remaining, 0);
1505
1506 r10_bio->master_bio = NULL;
1507 r10_bio->sector = sector_nr;
1508 set_bit(R10BIO_IsSync, &r10_bio->state);
1509 raid10_find_phys(conf, r10_bio);
1510 r10_bio->sectors = (sector_nr | conf->chunk_mask) - sector_nr +1;
1511
1512 for (i=0; i<conf->copies; i++) {
1513 int d = r10_bio->devs[i].devnum;
1514 bio = r10_bio->devs[i].bio;
1515 bio->bi_end_io = NULL;
1516 if (conf->mirrors[d].rdev == NULL ||
NeilBrownb2d444d2005-11-08 21:39:31 -08001517 test_bit(Faulty, &conf->mirrors[d].rdev->flags))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001518 continue;
1519 atomic_inc(&conf->mirrors[d].rdev->nr_pending);
1520 atomic_inc(&r10_bio->remaining);
1521 bio->bi_next = biolist;
1522 biolist = bio;
1523 bio->bi_private = r10_bio;
1524 bio->bi_end_io = end_sync_read;
1525 bio->bi_rw = 0;
1526 bio->bi_sector = r10_bio->devs[i].addr +
1527 conf->mirrors[d].rdev->data_offset;
1528 bio->bi_bdev = conf->mirrors[d].rdev->bdev;
1529 count++;
1530 }
1531
1532 if (count < 2) {
1533 for (i=0; i<conf->copies; i++) {
1534 int d = r10_bio->devs[i].devnum;
1535 if (r10_bio->devs[i].bio->bi_end_io)
1536 rdev_dec_pending(conf->mirrors[d].rdev, mddev);
1537 }
1538 put_buf(r10_bio);
1539 biolist = NULL;
1540 goto giveup;
1541 }
1542 }
1543
1544 for (bio = biolist; bio ; bio=bio->bi_next) {
1545
1546 bio->bi_flags &= ~(BIO_POOL_MASK - 1);
1547 if (bio->bi_end_io)
1548 bio->bi_flags |= 1 << BIO_UPTODATE;
1549 bio->bi_vcnt = 0;
1550 bio->bi_idx = 0;
1551 bio->bi_phys_segments = 0;
1552 bio->bi_hw_segments = 0;
1553 bio->bi_size = 0;
1554 }
1555
1556 nr_sectors = 0;
1557 do {
1558 struct page *page;
1559 int len = PAGE_SIZE;
1560 disk = 0;
1561 if (sector_nr + (len>>9) > max_sector)
1562 len = (max_sector - sector_nr) << 9;
1563 if (len == 0)
1564 break;
1565 for (bio= biolist ; bio ; bio=bio->bi_next) {
1566 page = bio->bi_io_vec[bio->bi_vcnt].bv_page;
1567 if (bio_add_page(bio, page, len, 0) == 0) {
1568 /* stop here */
1569 struct bio *bio2;
1570 bio->bi_io_vec[bio->bi_vcnt].bv_page = page;
1571 for (bio2 = biolist; bio2 && bio2 != bio; bio2 = bio2->bi_next) {
1572 /* remove last page from this bio */
1573 bio2->bi_vcnt--;
1574 bio2->bi_size -= len;
1575 bio2->bi_flags &= ~(1<< BIO_SEG_VALID);
1576 }
1577 goto bio_full;
1578 }
1579 disk = i;
1580 }
1581 nr_sectors += len>>9;
1582 sector_nr += len>>9;
1583 } while (biolist->bi_vcnt < RESYNC_PAGES);
1584 bio_full:
1585 r10_bio->sectors = nr_sectors;
1586
1587 while (biolist) {
1588 bio = biolist;
1589 biolist = biolist->bi_next;
1590
1591 bio->bi_next = NULL;
1592 r10_bio = bio->bi_private;
1593 r10_bio->sectors = nr_sectors;
1594
1595 if (bio->bi_end_io == end_sync_read) {
1596 md_sync_acct(bio->bi_bdev, nr_sectors);
1597 generic_make_request(bio);
1598 }
1599 }
1600
NeilBrown57afd892005-06-21 17:17:13 -07001601 if (sectors_skipped)
1602 /* pretend they weren't skipped, it makes
1603 * no important difference in this case
1604 */
1605 md_done_sync(mddev, sectors_skipped, 1);
1606
Linus Torvalds1da177e2005-04-16 15:20:36 -07001607 return sectors_skipped + nr_sectors;
1608 giveup:
1609 /* There is nowhere to write, so all non-sync
1610 * drives must be failed, so try the next chunk...
1611 */
1612 {
NeilBrown57afd892005-06-21 17:17:13 -07001613 sector_t sec = max_sector - sector_nr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001614 sectors_skipped += sec;
1615 chunks_skipped ++;
1616 sector_nr = max_sector;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001617 goto skipped;
1618 }
1619}
1620
1621static int run(mddev_t *mddev)
1622{
1623 conf_t *conf;
1624 int i, disk_idx;
1625 mirror_info_t *disk;
1626 mdk_rdev_t *rdev;
1627 struct list_head *tmp;
1628 int nc, fc;
1629 sector_t stride, size;
1630
1631 if (mddev->level != 10) {
1632 printk(KERN_ERR "raid10: %s: raid level not set correctly... (%d)\n",
1633 mdname(mddev), mddev->level);
1634 goto out;
1635 }
1636 nc = mddev->layout & 255;
1637 fc = (mddev->layout >> 8) & 255;
1638 if ((nc*fc) <2 || (nc*fc) > mddev->raid_disks ||
1639 (mddev->layout >> 16)) {
1640 printk(KERN_ERR "raid10: %s: unsupported raid10 layout: 0x%8x\n",
1641 mdname(mddev), mddev->layout);
1642 goto out;
1643 }
1644 /*
1645 * copy the already verified devices into our private RAID10
1646 * bookkeeping area. [whatever we allocate in run(),
1647 * should be freed in stop()]
1648 */
1649 conf = kmalloc(sizeof(conf_t), GFP_KERNEL);
1650 mddev->private = conf;
1651 if (!conf) {
1652 printk(KERN_ERR "raid10: couldn't allocate memory for %s\n",
1653 mdname(mddev));
1654 goto out;
1655 }
1656 memset(conf, 0, sizeof(*conf));
1657 conf->mirrors = kmalloc(sizeof(struct mirror_info)*mddev->raid_disks,
1658 GFP_KERNEL);
1659 if (!conf->mirrors) {
1660 printk(KERN_ERR "raid10: couldn't allocate memory for %s\n",
1661 mdname(mddev));
1662 goto out_free_conf;
1663 }
1664 memset(conf->mirrors, 0, sizeof(struct mirror_info)*mddev->raid_disks);
1665
1666 conf->near_copies = nc;
1667 conf->far_copies = fc;
1668 conf->copies = nc*fc;
1669 conf->chunk_mask = (sector_t)(mddev->chunk_size>>9)-1;
1670 conf->chunk_shift = ffz(~mddev->chunk_size) - 9;
1671 stride = mddev->size >> (conf->chunk_shift-1);
1672 sector_div(stride, fc);
1673 conf->stride = stride << conf->chunk_shift;
1674
1675 conf->r10bio_pool = mempool_create(NR_RAID10_BIOS, r10bio_pool_alloc,
1676 r10bio_pool_free, conf);
1677 if (!conf->r10bio_pool) {
1678 printk(KERN_ERR "raid10: couldn't allocate memory for %s\n",
1679 mdname(mddev));
1680 goto out_free_conf;
1681 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001682
1683 ITERATE_RDEV(mddev, rdev, tmp) {
1684 disk_idx = rdev->raid_disk;
1685 if (disk_idx >= mddev->raid_disks
1686 || disk_idx < 0)
1687 continue;
1688 disk = conf->mirrors + disk_idx;
1689
1690 disk->rdev = rdev;
1691
1692 blk_queue_stack_limits(mddev->queue,
1693 rdev->bdev->bd_disk->queue);
1694 /* as we don't honour merge_bvec_fn, we must never risk
1695 * violating it, so limit ->max_sector to one PAGE, as
1696 * a one page request is never in violation.
1697 */
1698 if (rdev->bdev->bd_disk->queue->merge_bvec_fn &&
1699 mddev->queue->max_sectors > (PAGE_SIZE>>9))
1700 mddev->queue->max_sectors = (PAGE_SIZE>>9);
1701
1702 disk->head_position = 0;
NeilBrownb2d444d2005-11-08 21:39:31 -08001703 if (!test_bit(Faulty, &rdev->flags) && test_bit(In_sync, &rdev->flags))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001704 conf->working_disks++;
1705 }
1706 conf->raid_disks = mddev->raid_disks;
1707 conf->mddev = mddev;
1708 spin_lock_init(&conf->device_lock);
1709 INIT_LIST_HEAD(&conf->retry_list);
1710
1711 spin_lock_init(&conf->resync_lock);
1712 init_waitqueue_head(&conf->wait_idle);
1713 init_waitqueue_head(&conf->wait_resume);
1714
NeilBrown6d508242005-09-09 16:24:03 -07001715 /* need to check that every block has at least one working mirror */
1716 if (!enough(conf)) {
1717 printk(KERN_ERR "raid10: not enough operational mirrors for %s\n",
1718 mdname(mddev));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001719 goto out_free_conf;
1720 }
1721
1722 mddev->degraded = 0;
1723 for (i = 0; i < conf->raid_disks; i++) {
1724
1725 disk = conf->mirrors + i;
1726
1727 if (!disk->rdev) {
1728 disk->head_position = 0;
1729 mddev->degraded++;
1730 }
1731 }
1732
1733
1734 mddev->thread = md_register_thread(raid10d, mddev, "%s_raid10");
1735 if (!mddev->thread) {
1736 printk(KERN_ERR
1737 "raid10: couldn't allocate thread for %s\n",
1738 mdname(mddev));
1739 goto out_free_conf;
1740 }
1741
1742 printk(KERN_INFO
1743 "raid10: raid set %s active with %d out of %d devices\n",
1744 mdname(mddev), mddev->raid_disks - mddev->degraded,
1745 mddev->raid_disks);
1746 /*
1747 * Ok, everything is just fine now
1748 */
1749 size = conf->stride * conf->raid_disks;
1750 sector_div(size, conf->near_copies);
1751 mddev->array_size = size/2;
1752 mddev->resync_max_sectors = size;
1753
NeilBrown7a5febe2005-05-16 21:53:16 -07001754 mddev->queue->unplug_fn = raid10_unplug;
1755 mddev->queue->issue_flush_fn = raid10_issue_flush;
1756
Linus Torvalds1da177e2005-04-16 15:20:36 -07001757 /* Calculate max read-ahead size.
1758 * We need to readahead at least twice a whole stripe....
1759 * maybe...
1760 */
1761 {
1762 int stripe = conf->raid_disks * mddev->chunk_size / PAGE_CACHE_SIZE;
1763 stripe /= conf->near_copies;
1764 if (mddev->queue->backing_dev_info.ra_pages < 2* stripe)
1765 mddev->queue->backing_dev_info.ra_pages = 2* stripe;
1766 }
1767
1768 if (conf->near_copies < mddev->raid_disks)
1769 blk_queue_merge_bvec(mddev->queue, raid10_mergeable_bvec);
1770 return 0;
1771
1772out_free_conf:
1773 if (conf->r10bio_pool)
1774 mempool_destroy(conf->r10bio_pool);
Jesper Juhl990a8ba2005-06-21 17:17:30 -07001775 kfree(conf->mirrors);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001776 kfree(conf);
1777 mddev->private = NULL;
1778out:
1779 return -EIO;
1780}
1781
1782static int stop(mddev_t *mddev)
1783{
1784 conf_t *conf = mddev_to_conf(mddev);
1785
1786 md_unregister_thread(mddev->thread);
1787 mddev->thread = NULL;
1788 blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
1789 if (conf->r10bio_pool)
1790 mempool_destroy(conf->r10bio_pool);
Jesper Juhl990a8ba2005-06-21 17:17:30 -07001791 kfree(conf->mirrors);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001792 kfree(conf);
1793 mddev->private = NULL;
1794 return 0;
1795}
1796
1797
1798static mdk_personality_t raid10_personality =
1799{
1800 .name = "raid10",
1801 .owner = THIS_MODULE,
1802 .make_request = make_request,
1803 .run = run,
1804 .stop = stop,
1805 .status = status,
1806 .error_handler = error,
1807 .hot_add_disk = raid10_add_disk,
1808 .hot_remove_disk= raid10_remove_disk,
1809 .spare_active = raid10_spare_active,
1810 .sync_request = sync_request,
1811};
1812
1813static int __init raid_init(void)
1814{
1815 return register_md_personality(RAID10, &raid10_personality);
1816}
1817
1818static void raid_exit(void)
1819{
1820 unregister_md_personality(RAID10);
1821}
1822
1823module_init(raid_init);
1824module_exit(raid_exit);
1825MODULE_LICENSE("GPL");
1826MODULE_ALIAS("md-personality-9"); /* RAID10 */